Upload
others
View
2
Download
0
Embed Size (px)
Citation preview
Research ArticleBlow-Up Phenomena for Nonlinear Reaction-DiffusionEquations under Nonlinear Boundary Conditions
Juntang Ding
School of Mathematical Sciences Shanxi University Taiyuan 030006 China
Correspondence should be addressed to Juntang Ding djuntangsxueducn
Received 20 November 2015 Accepted 6 March 2016
Academic Editor Leszek Olszowy
Copyright copy 2016 Juntang DingThis is an open access article distributed under the Creative Commons Attribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
This paper deals with blow-up and global solutions of the following nonlinear reaction-diffusion equations under nonlinearboundary conditions (119892(119906))
119905= nabla sdot (119886(119906)nabla119906) + 119891(119906) in Ω times (0 119879) 120597119906120597119899 = 119887(119909 119906 119905) on 120597Ω times (0 119879) 119906(119909 0) = 119906
0(119909) gt 0 in Ω
where Ω sub R119873 (119873 ge 2) is a bounded domain with smooth boundary 120597Ω We obtain the conditions under which the solutionseither exist globally or blow up in a finite time by constructing auxiliary functions and using maximum principles Moreover theupper estimates of the ldquoblow-up timerdquo the ldquoblow-up raterdquo and the global solutions are also given
1 Introduction
During the past few decades the blow-up phenomena forthe nonlinear reaction-diffusion equations have been studiedby a large number of authors and the reader is referred to[1ndash8] and the references therein In this paper we considerthe following nonlinear reaction-diffusion problem undernonlinear conditions
(119892 (119906))119905= nabla sdot (119886 (119906) nabla119906) + 119891 (119906) in Ω times (0 119879)
120597119906
120597119899= 119887 (119909 119906 119905) on 120597Ω times (0 119879)
119906 (119909 0) = 1199060(119909) gt 0 in Ω
(1)
where Ω sub R119873 (119873 ge 2) is a bounded domain withsmooth boundary 120597Ω 120597119906120597119899 represents the outward normalderivative on 120597Ω and 119879 is the maximal existence time of119906 Set R
+fl (0 +infin) We assume throughout the paper
that 119886(119904) is a positive 1198622(R+) function 119892(119904) is a 1198622(R
+)
function 1198921015840(119904) gt 0 for any 119904 isin R+ 119891(119904) is a nonnegative
1198621(R+) function 119887(119909 119904 119905) is a nonnegative1198621(120597ΩtimesR
+timesR+)
function and 1199060(119909) is a positive1198622(R
+) function and satisfies
the compatibility conditions Under the above assumptionsthe local existence and uniqueness of classical solution ofproblem (1) were established by Amann [9] Furthermore itfollows frommaximum principle [10] and regularity theorem
[11] that the solution 119906(119909 119905) is positive and 119906(119909 119905) isin 1198623(Ω times
(0 119879)) cap 1198622(Ω times (0 119879))Many authors have investigated blow-up and global
solutions of nonlinear reaction-diffusion equations undernonlinear boundary conditions and have obtained a lot ofinteresting results (see eg [12ndash20]) Tomy knowledge somespecial cases of (1) have been studied Zhang [21] consideredthe following problem
(119892 (119906))119905= Δ119906 + 119891 (119906) in Ω times (0 119879)
120597119906
120597119899= 119887 (119906) on 120597Ω times (0 119879)
119906 (119909 0) = 1199060(119909) gt 0 in Ω
(2)
where Ω sub R119873 (119873 ge 2) is a bounded domain with smoothboundary 120597Ω By constructing auxiliary functions and usingmaximum principles the existence of blow-up and globalsolutions were obtained under appropriate assumptions onthe functions 119887 119891 119892 and 119906
0 Zhang et al [22] dealt with the
following problem
(119892 (119906))119905= nabla sdot (119886 (119906) nabla119906) + 119891 (119906) in Ω times (0 119879)
120597119906
120597119899= 119887 (119906) on 120597Ω times (0 119879)
119906 (119909 0) = 1199060(119909) gt 0 in Ω
(3)
Hindawi Publishing CorporationJournal of Function SpacesVolume 2016 Article ID 8107657 7 pageshttpdxdoiorg10115520168107657
2 Journal of Function Spaces
where Ω sub R119873 (119873 ge 2) is a bounded domain with smoothboundary 120597Ω Some conditions on nonlinearities and theinitial data were given to ensure that 119906(119909 119905) exists globallyor blows up at some finite time 119879 In addition the upperestimates of the global solution the ldquoblow-up timerdquo and theldquoblow-up raterdquo were also established
In this paper we study reaction-diffusion problem (1) It iswell known that 119891(119906) 119892(119906) 119886(119906) and 119887(119909 119906 119905) are nonlinearreaction nonlinear diffusion nonlinear convection and non-linear boundary flux respectively What interactions amongthe four nonlinear mechanisms result in the blow-up andglobal solutions of (1) is investigated in this work We notethat the boundary flux function 119887(119909 119906 119905) depends not onlyon the concentration variable 119906 but also on the space variable119909 and the time variable 119905 Hence it seems that the methodsof [21 22] are not applicable for problem (1) In this paperby constructing completely different auxiliary functions fromthose in [21 22] and technically using maximum principleswe obtain the existence theorems of the blow-up and globalsolution Moreover the upper estimates of ldquoblow-up timerdquoldquoblow-up raterdquo and global solution are also given Ourresults can be seen as the extension and supplement of thoseobtained in [21 22]
The present work is organized as follows In Section 2 wedeal with the blow-up solution of (1) Section 3 is devotedto the global solution of (1) As applications of the obtainedresults some examples are presented in Section 4
2 Blow-Up Solution
In this section we discuss what interactions among the fournonlinear mechanisms of (1) result in the blow-up solutionOur main result in this section is the following theorem
Theorem 1 Let 119906(119909 119905) be a solution of problem (1) Assumethat the following conditions (i)ndash(iv) are satisfied
(i) For 119904 isin R+
119886 (119904) minus 1198861015840(119904) ge 0
1198911015840(119904) minus 119891 (119904) ge 0
(119886 (119904)
1198921015840 (119904))
1015840
ge 0
(4)
(ii) For (119909 119904 119905) isin 120597Ω times R+times R+
119887119904(119909 119904 119905) minus 119887 (119909 119904 119905) le 0
119886 (119904) 119887 (119909 119904 119905) minus (119886 (119904) 119887 (119909 119904 119905))119904le 0
119887119905(119909 119904 119905) ge 0
(5)
(iii) Consider the following
120572 fl min119863
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
e11990601198921015840 (1199060)
gt 0 (6)
(iv) Consider the following
int+infin
1198720
119886 (119904)
e119904d119904 lt +infin 119872
0fl max119863
1199060(119909) (7)
Then 119906(119909 119905) blows up in a finite time 119879 and
119879 le1
120572int+infin
1198720
119886 (119904)
e119904d119904
119906 (119909 119905) le 119867minus1
(120572 (119879 minus 119905))
(8)
where
119867(119910) fl int+infin
119910
119886 (119904)
e119904d119904 119910 gt 0 (9)
and 119867minus1 is the inverse function of 119867
Proof Introduce an auxiliary function
119875 (119909 119905) fl minuseminus119906119906119905+ 120572
1
119886 (119906) (10)
and then we have
nabla119875 = eminus119906119906119905nabla119906 minus eminus119906nabla119906
119905minus 120572
1198861015840
1198862nabla119906 (11)
Δ119875 = minuseminus119906119906119905|nabla119906|2+ 2eminus119906nabla119906 sdot nabla119906
119905+ eminus119906119906
119905Δ119906
minus eminus119906Δ119906119905+ (2120572
(1198861015840)2
1198863minus 120572
11988610158401015840
1198862)|nabla119906|
2
minus 1205721198861015840
1198862Δ119906
(12)
119875119905= eminus119906 (119906
119905)2
minus eminus119906 (119906119905)119905minus 120572
1198861015840
1198862119906119905
= eminus119906 (119906119905)2
minus eminus119906 ( 119886
1198921015840Δ119906 +
1198861015840
1198921015840|nabla119906|2+
119891
1198921015840)119905
minus 1205721198861015840
1198862119906119905
= eminus119906 (119906119905)2
+ (11988611989210158401015840
(1198921015840)2minus
1198861015840
1198921015840) eminus119906119906
119905Δ119906
minus119886
1198921015840eminus119906Δ119906
119905+ (
119886101584011989210158401015840
(1198921015840)2minus
11988610158401015840
1198921015840) eminus119906119906
119905|nabla119906|2
minus 21198861015840
1198921015840eminus119906 (nabla119906 sdot nabla119906
119905) + (
11989111989210158401015840
(1198921015840)2minus
1198911015840
1198921015840) eminus119906119906
119905
minus 1205721198861015840
1198862119906119905
(13)
Journal of Function Spaces 3
It follows from (12) and (13) that
119886
1198921015840Δ119875 minus 119875
119905= (
11988610158401015840
1198921015840minus
119886
1198921015840minus
119886101584011989210158401015840
(1198921015840)2) eminus119906119906
119905|nabla119906|2
+ (2119886
1198921015840+ 2
1198861015840
1198921015840) eminus119906 (nabla119906 sdot nabla119906
119905)
+ (1198861015840
1198921015840+
119886
1198921015840minus
11988611989210158401015840
(1198921015840)2) eminus119906119906
119905Δ119906
+ (2120572(1198861015840)2
11988621198921015840minus 120572
11988610158401015840
1198861198921015840) |nabla119906|
2
minus 1205721198861015840
1198861198921015840Δ119906 minus eminus119906 (119906
119905)2
+ (1198911015840
1198921015840minus
11989111989210158401015840
(1198921015840)2) eminus119906119906
119905+ 120572
1198861015840
1198862119906119905
(14)
The first equation of (1) implies
Δ119906 =1198921015840
119886119906119905minus
1198861015840
119886|nabla119906|2minus
119891
119886 (15)
Inserting (15) into (14) we obtain
119886
1198921015840Δ119875 minus 119875
119905= (
11988610158401015840
1198921015840minus
119886
1198921015840minus
(1198861015840)2
1198861198921015840minus
1198861015840
1198921015840) eminus119906119906
119905|nabla119906|2
+ (2119886
1198921015840+ 2
1198861015840
1198921015840) eminus119906 (nabla119906 sdot nabla119906
119905)
+1198921015840
119886(
119886
1198921015840)
1015840
eminus119906 (119906119905)2
+ (1198911015840
1198921015840minus
1198861015840119891
1198861198921015840minus
119891
1198921015840) eminus119906119906
119905
+ (3120572(1198861015840)2
11988621198921015840minus 120572
11988610158401015840
1198861198921015840) |nabla119906|
2+ 120572
1198861015840119891
11988621198921015840
(16)
It follows from (11) that
nabla119906119905= minuse119906nabla119875 + 119906
119905nabla119906 minus 120572
1198861015840
1198862e119906nabla119906 (17)
Substituting (17) into (16) we get
119886
1198921015840Δ119875 + 2
119886 + 1198861015840
1198921015840nabla119906 sdot nabla119875 minus 119875
119905
= (11988610158401015840
1198921015840+
119886
1198921015840minus
(1198861015840)2
1198861198921015840+
1198861015840
1198921015840) eminus119906119906
119905|nabla119906|2
+ (120572(1198861015840)2
11988621198921015840minus 2120572
1198861015840
1198861198921015840minus 120572
11988610158401015840
1198861198921015840) |nabla119906|
2
+1198921015840
119886(
119886
1198921015840)
1015840
eminus119906 (119906119905)2
+ (1198911015840
1198921015840minus
1198861015840119891
1198861198921015840minus
119891
1198921015840) eminus119906119906
119905+ 120572
1198861015840119891
11988621198921015840
(18)
By (10) we have
119906119905= minuse119906119875 + 120572e119906 1
119886 (19)
Now we insert (19) into (18) to deduce
119886
1198921015840Δ119875 + 2
1198861015840 + 119886
1198921015840nabla119906 sdot nabla119875
+119886
1198921015840[1 +
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
minus119891
119886119875
minus 119875119905
= 1205721
1198861198921015840(119886 minus 119886
1015840) |nabla119906|
2+
1198921015840
119886(
119886
1198921015840)
1015840
eminus119906 (119906119905)2
+ 1205721
1198861198921015840(1198911015840minus 119891)
(20)
Assumptions (4) ensure that the right side in equality (20) isnonnegative that is
119886
1198921015840Δ119875 + 2
1198861015840 + 119886
1198921015840nabla119906 sdot nabla119875
+119886
1198921015840[1 +
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
minus119891
119886119875
minus 119875119905ge 0 in Ω times (0 119879)
(21)
4 Journal of Function Spaces
Next it follows from (1) and (10) that
120597119875
120597119899= eminus119906119906
119905
120597119906
120597119899minus eminus119906
120597119906119905
120597119899minus 120572
1198861015840
1198862120597119906
120597119899
= eminus119906119906119905119887 minus eminus119906 (120597119906
120597119899)119905
minus 1205721198861015840
1198862119887
= eminus119906119906119905119887 minus eminus119906 (119887 (119909 119906 119905))
119905minus 120572
1198861015840
1198862119887
= (119887 minus 119887119906) eminus119906119906
119905minus eminus119906119887
119905minus 120572
1198861015840
1198862119887
= (119887 minus 119887119906) (minus119875 + 120572
1
119886) minus eminus119906119887
119905minus 120572
1198861015840
1198862119887
= (119887119906minus 119887) 119875 + 120572
119886119887 minus (119886119887)119906
1198862minus eminus119906119887
119905
on 120597Ω times (0 119879)
(22)
We note that (6) implies
maxΩ
119875 (119909 0) = maxΩ
minuseminus1199060 (1199060)119905+ 120572
1
119886 (1199060)
= maxΩ
minusnabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)
e11990601198921015840 (1199060)
+ 1205721
119886 (1199060)
= maxΩ
1
119886 (1199060)(120572
minus119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
e11990601198921015840 (1199060)
) = 0
(23)
There (21)ndash(23) assumption (5) and the maximum principle[10] imply that the maximum of the function 119875 in Ω times [0T)
is zero In fact if the function 119875 takes a positive maximum atpoint (119909
0 1199050) isin 120597Ω times (0 119879) then we have
119875 (1199090 1199050) gt 0
120597119875
120597119899
10038161003816100381610038161003816100381610038161003816(1199090 1199050)gt 0 (24)
Using assumption (5) and the fact that119875(1199090 1199050) gt 0 it follows
from (22) that
120597119875
120597119899
10038161003816100381610038161003816100381610038161003816(1199090 1199050)le 0 (25)
which contradicts the second inequality in (24) Hence themaximum of the function 119875 in Ω times [0 119879) is zero Now wehave
119875 le 0 in Ω times [0 119879) (26)
that is
119886 (119906)
e119906119906119905ge 120572 (27)
At the point 1199090
isin Ω where 1199060(1199090) = 119872
0 integrating
inequality (27) from 0 to 119905 we arrive at
int119905
0
119886 (119906)
e119906119906119905d119905 = int
119906(1199090119905)
1198720
119886 (119904)
e119904d119904 ge 120572119905 (28)
Inequality (28) and assumption (7) imply that 119906(119909 119905) blowsup in finite time 119905 = 119879 Now we let 119905 rarr 119879 in (28) to deduce
119879 le1
120572int+infin
1198720
119886 (119904)
e119904d119904 (29)
For each fixed 119909 isin Ω integrating inequality (27) from 119905 to119904 (0 lt 119905 lt 119904 lt 119879) we get
119867(119906 (119909 119905)) ge 119867 (119906 (119909 119905)) minus 119867 (119906 (119909 119904))
= int+infin
119906(119909119905)
119886 (119904)
e119904d119904 minus int
+infin
119906(119909119904)
119886 (119904)
e119904d119904
= int119906(119909119904)
119906(119909119905)
119886 (119904)
e119904d119904 = int
119904
119905
119886 (119906)
e119906119906119905d119905
ge 120572 (119904 minus 119905)
(30)
In the above inequality letting 119904 rarr 119879 we obtain
119867(119906 (119909 119905)) ge 120572 (119879 minus 119905) (31)
We note that 119867 is a strictly decreasing function Hence
119906 (119909 119905) le 119867minus1
(120572 (119879 minus 119905)) (32)
The proof is complete
3 Global Solution
In this section we study what interactions among the fournonlinear mechanisms of (1) result in the global solution of(1) The main results of this section are formulated in thefollowing theorem
Theorem 2 Let 119906(119909 119905) be a solution of problem (1) Assumethat the following conditions (i)ndash(iv) are fulfilled
(i) For 119904 isin R+
119886 (119904) + 1198861015840(119904) le 0
119891 (119904) + 1198911015840(119904) le 0
(119886 (119904)
1198921015840 (119904))
1015840
le 0
(33)
(ii) For (119909 119904 119905) isin 120597Ω times R+times R+
119887 (119909 119904 119905) + 119887119904(119909 119904 119905) le 0
119886 (119904) 119887 (119909 119904 119905) + (119886 (119904) 119887 (119909 119904 119905))119904le 0
119887119905(119909 119904 119905) le 0
(34)
Journal of Function Spaces 5
(iii) Consider the following
120573 fl maxΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
gt 0 (35)
(iv) Consider the following
int+infin
1198980
119886 (119904)
eminus119904d119904 = +infin 119898
0fl minΩ
1199060(119909) (36)
Then 119906(119909 119905) must be a global solution and
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) (37)
where
119870(119910) fl int119910
1198980
119886 (119904)
eminus119904d119904 119910 ge 119898
0 (38)
and 119870 is the inverse function of 119870
Proof We consider an auxiliary function
119876 (119909 119905) fl minuse119906119906119905+ 120573
1
119886 (119906) (39)
Using the same reasoning process as that of (11)ndash(20) weobtain
119886
1198921015840Δ119876 + 2
1198861015840 minus 119886
1198921015840nabla119906 sdot nabla119876
+119886
1198921015840[1 minus
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
+119891
119886119876
minus 119876119905
= 1205731
1198861198921015840(119886 + 119886
1015840) |nabla119906|
2+
1198921015840
119886(
119886
1198921015840)
1015840
e119906 (119906119905)2
+ 1205731
1198861198921015840(1198911015840+ 119891)
(40)
Assumptions (33) imply that the right side of (40) is nonpos-itive that is
119886
1198921015840Δ119876 + 2
1198861015840 minus 119886
1198921015840nabla119906 sdot nabla119876
+119886
1198921015840[1 minus
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
+119891
119886119876
minus 119876119905le 0 in Ω times (0 119879)
(41)
By (1) and (39) we get
120597119876
120597119899= minuse119906119906
119905
120597119906
120597119899minus e119906
120597119906119905
120597119899minus 120573
1198861015840
1198862120597119906
120597119899
= minuse119906119906119905119887 minus e119906 (120597119906
120597119899)119905
minus 1205731198861015840
1198862119887
= minuse119906119906119905119887 minus e119906 (119887 (119909 119906 119905))
119905minus 120573
1198861015840
1198862119887
= minus (119887 + 119887119906) e119906119906119905minus e119906119887119905minus 120573
1198861015840
1198862119887
= (119887 + 119887119906) (119876 minus 120573
1
119886) minus e119906119887
119905minus 120573
1198861015840
1198862119887
= (119887 + 119887119906) 119876 minus 120573
119886119887 + (119886119887)119906
1198862minus e119906119887119905
on 120597Ω times (0 119879)
(42)
Assumption (35) implies
minΩ
119876 (119909 0) = minΩ
minuse1199060 (1199060)119905+ 120573
1
119886 (1199060)
= minΩ
minusnabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)
eminus11990601198921015840 (1199060)
+ 1205731
119886 (1199060)
= minΩ
1
119886 (1199060)(120573
minus119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
) = 0
(43)
It follows from (41)ndash(43) (34) and the maximum principlethat the minimum of 119876 in Ω times [0 119879) is zero Hence we havethe following inequality
119876 ge 0 in Ω times [0 119879) (44)
that is
119886 (119906)
eminus119906119906119905le 120573 (45)
For each fixed 119909 isin Ω we integrate (45) from 0 to 119905 to deduce
1
120573int119905
0
119886 (119906)
eminus119906119906119905d119905 =
1
120573int119906(119909119905)
1199060(119909)
119886 (119904)
eminus119904d119904 le 119905 (46)
Inequality (46) and assumption (36) imply that 119906 must be aglobal solution Furthermore it follows from (45) that
119870 (119906 (119909 119905)) minus 119870 (1199060(119909))
= int119906(119909119905)
1198980
119886 (119904)
eminus119904d119904 minus int
1199060(119909)
1198980
119886 (119904)
eminus119904d119904 = int
119906(119909119905)
1199060(119909)
119886 (119904)
eminus119904d119904
= int119905
0
119886 (119906)
eminus119906119906119905d119905 le 120573119905
(47)
6 Journal of Function Spaces
Since 119870 is a strictly increasing function we obtain
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) (48)
The proof is complete
4 Applications
When 119886(119906) = 1 and 119887(119909 119906 119905) = 119887(119906) the results ofTheorems 1ndash2 still hold In this sense our results extend andsupplement those obtained in [21 22]
In the following we give a few examples to demonstratethe applications of Theorems 1ndash2
Example 3 Let 119906 be a solution of the following problem
(119906
2+ e1199062)
119905
= nabla sdot (e1199062nabla119906) + e119906 in Ω times (0 119879)
120597119906
120597119899= e(34)(119906minus2) + e119906minus2+119905|119909|
2
on 120597Ω times (0 119879)
119906 (119909 0) = 1 + |119909|2 in Ω
(49)
where Ω = 119909 = (1199091 1199092 1199093) | |119909|2 = 1199092
1+ 11990922+ 11990923
lt 1 Wenote
119886 (119906) = e2119906
119892 (119906) =119906
2+ e1199062
119891 (119906) = e119906
119887 (119909 119906 119905) = e(34)(119906minus2) + e119906minus2+119905|119909|2
(50)
In order to calculate the constant 120572 we set
120596 = |119909|2 (51)
and then 0 le 120596 le 1 and
120572 = minΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
e11990601198921015840 (1199060)
= minΩ
2 [6 + 2 |119909|2+ e(12)(1+|119909|
2)]
e(12)(1+|119909|2) + 1
= min0le120596le1
2 [6 + 2120596 + e(12)(1+120596)]
e(12)(1+120596) + 1 =
2 (8 + e)1 + e
(52)
We can check that (4) (5) and (7) hold It follows fromTheorem 1 that 119906(119909 119905) blows up in a finite time 119879 and
119879 le1
120572int+infin
1198720
119886 (119904)
e119904d119904 =
1 + e2 (8 + e)
int+infin
2
eminus1199042d119904
=1 + e
e (8 + e)
119906 (119909 119905) le 119867minus1
(120572 (119879 minus 119905)) = 2 ln 1 + e(8 + e) (119879 minus 119905)
(53)
Example 4 Let 119906 be a solution of the following problem
(119906e119906)119905= nabla sdot (
eminus119906
1 + 119906nabla119906) + eminus119906 in Ω times (0 119879)
120597119906
120597119899= eminus2119906 + eminus119906minus119905|119909|
2
on 120597Ω times (0 119879)
119906 (119909 0) = 1 + |119909|2 in Ω
(54)
where Ω = 119909 = (1199091 1199092 1199093) | |119909|2 = 1199092
1+ 11990922+ 11990923lt 1 Now
we have
119886 (119906) =eminus119906
1 + 119906
119892 (119906) = 119906e119906
119891 (119906) = eminus119906
119887 (119909 119906 119905) = eminus2119906 + eminus119906minus119905|119909|2
(55)
Setting
120596 = |119909|2 (56)
we get 0 le 120596 le 1 and
120573 = maxΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
= maxΩ
16 minus 2 |119909|2minus 3 |119909|
4
e2(1+|119909|2) (2 + |119909|2)4
= max0le120596le1
16 minus 2120596 minus 31205962
e2(1+120596) (2 + 120596)4 = eminus2
(57)
We can also check that (33) (34) and (36) hold HenceTheorem 2 implies 119906 must be a global solution and
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) = (2 + |119909|
2) e119905eminus2
minus 1 (58)
Remark 5 When the functions 119886 119887 119891 and 119892 are all exponen-tial functions Theorems 1 and 2 can be used When not all ofthem are exponential functionsTheorems 1 and 2 can be usedin some special cases
Competing Interests
The author declares that there are no competing interestsregarding the publication of this paper
Acknowledgments
This work was supported by the National Natural ScienceFoundation of China (no 61473180)
References
[1] PQuittner andP Souplet Superlinear Parabolic Problems Blow-Up Global Existence and Steady States Birkhauser AdvancedTexts Birkhauser Basel Switzerland 2007
Journal of Function Spaces 7
[2] MMarras and S Vernier Piro ldquoOn global existence and boundsfor blow-up time in nonlinear parabolic problems with timedependent coefficientsrdquo Discrete and Continuous DynamicalSystems vol 2013 pp 535ndash544 2013
[3] L E Payne G A Philippin and P W Schaefer ldquoBlow-upphenomena for some nonlinear parabolic problemsrdquoNonlinearAnalysis Theory Methods amp Applications vol 69 no 10 pp3495ndash3502 2008
[4] S H Chen ldquoGlobal existence and nonexistence for some degen-erate and quasilinear parabolic systemsrdquo Journal of DifferentialEquations vol 245 no 4 pp 1112ndash1136 2008
[5] S H Chen and K MacDonald ldquoGlobal and blowup solutionsfor general quasilinear parabolic systemsrdquo Nonlinear AnalysisReal World Applications vol 14 no 1 pp 423ndash433 2013
[6] J T Ding and H J Hu ldquoBlow-up and global solutions for aclass of nonlinear reaction diffusion equations under Dirichletboundary conditionsrdquo Journal of Mathematical Analysis andApplications vol 433 no 2 Article ID 19743 pp 1718ndash17352016
[7] J T Ding and M Wang ldquoBlow-up solutions global existenceand exponential decay estimates for second order parabolicproblemsrdquo Boundary Value Problems vol 2015 no 168 16pages 2015
[8] L L Zhang ldquoBlow-up of solutions for a class of nonlinearparabolic equationsrdquo Zeitschrift fur Analysis und Ihre Anwen-dungen vol 25 no 4 pp 479ndash486 2006
[9] H Amann ldquoQuasilinear parabolic systems under nonlinearboundary conditionsrdquo Archive for Rational Mechanics andAnalysis vol 92 no 2 pp 153ndash192 1986
[10] R SperbMaximumPrinciples andTheirApplications AcademicPress New York NY USA 1981
[11] A Friedman Partial Differential Equation of Parabolic TypePrentice-Hall Englewood Cliffs NJ USA 1964
[12] J Harada ldquoNon self-similar blow-up solutions to the heat equa-tion with nonlinear boundary conditionsrdquo Nonlinear AnalysisTheory Methods amp Applications vol 102 no 2 pp 36ndash83 2014
[13] J Harada and K Mihara ldquoBlow-up rate for radially symmetricsolutions of some parabolic equations with nonlinear boundaryconditionsrdquo Journal of Differential Equations vol 253 no 5 pp1647ndash1663 2012
[14] Y Liu ldquoLower bounds for the blow-up time in a non-local reac-tion diffusion problem under nonlinear boundary conditionsrdquoMathematical and ComputerModelling vol 57 no 3-4 pp 926ndash931 2013
[15] Y Liu S G Luo and Y H Ye ldquoBlow-up phenomena for aparabolic problemwith a gradient nonlinearity under nonlinearboundary conditionsrdquo Computers ampMathematics with Applica-tions vol 65 no 8 pp 1194ndash1199 2013
[16] F S Li and J L Li ldquoGlobal existence and blow-up phenom-ena for nonlinear divergence form parabolic equations withinhomogeneous Neumann boundary conditionsrdquo Journal ofMathematical Analysis and Applications vol 385 no 2 pp1005ndash1014 2012
[17] F Liang ldquoBlow-up and global solutions for nonlinear reaction-diffusion equations with nonlinear boundary conditionrdquoApplied Mathematics and Computation vol 218 no 8 pp3993ndash3999 2011
[18] L E Payne G A Philippin and S Vernier Piro ldquoBlow-up phenomena for a semilinear heat equation with nonlinearboundary condition IIrdquoNonlinear Analysis Theory Methods ampApplications vol 73 no 4 pp 971ndash978 2010
[19] J Ding X Gao and S Li ldquoGlobal existence and blow-up prob-lems for reaction diffusion model with multiple nonlinearitiesrdquoJournal of Mathematical Analysis and Applications vol 343 no1 pp 159ndash169 2008
[20] Y W Qi M X Wang and Z J Wang ldquoExistence and non-existence of global solutions of diffusion systems with nonlin-ear boundary conditionsrdquo Proceedings of the Royal Society ofEdinburghmdashSection A Mathematics vol 134 no 6 pp 1199ndash1217 2004
[21] H L Zhang ldquoBlow-up solutions and global solutions for non-linear parabolic problemsrdquoNonlinear AnalysisTheory Methodsamp Applications vol 69 no 12 pp 4567ndash4574 2008
[22] L L Zhang N Zhang and L X Li ldquoBlow-up solutions andglobal existence for a kind of quasilinear reaction-diffusionequationsrdquo Zeitschrift fur Analysis und ihre Anwendungen vol33 no 3 pp 247ndash258 2014
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
2 Journal of Function Spaces
where Ω sub R119873 (119873 ge 2) is a bounded domain with smoothboundary 120597Ω Some conditions on nonlinearities and theinitial data were given to ensure that 119906(119909 119905) exists globallyor blows up at some finite time 119879 In addition the upperestimates of the global solution the ldquoblow-up timerdquo and theldquoblow-up raterdquo were also established
In this paper we study reaction-diffusion problem (1) It iswell known that 119891(119906) 119892(119906) 119886(119906) and 119887(119909 119906 119905) are nonlinearreaction nonlinear diffusion nonlinear convection and non-linear boundary flux respectively What interactions amongthe four nonlinear mechanisms result in the blow-up andglobal solutions of (1) is investigated in this work We notethat the boundary flux function 119887(119909 119906 119905) depends not onlyon the concentration variable 119906 but also on the space variable119909 and the time variable 119905 Hence it seems that the methodsof [21 22] are not applicable for problem (1) In this paperby constructing completely different auxiliary functions fromthose in [21 22] and technically using maximum principleswe obtain the existence theorems of the blow-up and globalsolution Moreover the upper estimates of ldquoblow-up timerdquoldquoblow-up raterdquo and global solution are also given Ourresults can be seen as the extension and supplement of thoseobtained in [21 22]
The present work is organized as follows In Section 2 wedeal with the blow-up solution of (1) Section 3 is devotedto the global solution of (1) As applications of the obtainedresults some examples are presented in Section 4
2 Blow-Up Solution
In this section we discuss what interactions among the fournonlinear mechanisms of (1) result in the blow-up solutionOur main result in this section is the following theorem
Theorem 1 Let 119906(119909 119905) be a solution of problem (1) Assumethat the following conditions (i)ndash(iv) are satisfied
(i) For 119904 isin R+
119886 (119904) minus 1198861015840(119904) ge 0
1198911015840(119904) minus 119891 (119904) ge 0
(119886 (119904)
1198921015840 (119904))
1015840
ge 0
(4)
(ii) For (119909 119904 119905) isin 120597Ω times R+times R+
119887119904(119909 119904 119905) minus 119887 (119909 119904 119905) le 0
119886 (119904) 119887 (119909 119904 119905) minus (119886 (119904) 119887 (119909 119904 119905))119904le 0
119887119905(119909 119904 119905) ge 0
(5)
(iii) Consider the following
120572 fl min119863
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
e11990601198921015840 (1199060)
gt 0 (6)
(iv) Consider the following
int+infin
1198720
119886 (119904)
e119904d119904 lt +infin 119872
0fl max119863
1199060(119909) (7)
Then 119906(119909 119905) blows up in a finite time 119879 and
119879 le1
120572int+infin
1198720
119886 (119904)
e119904d119904
119906 (119909 119905) le 119867minus1
(120572 (119879 minus 119905))
(8)
where
119867(119910) fl int+infin
119910
119886 (119904)
e119904d119904 119910 gt 0 (9)
and 119867minus1 is the inverse function of 119867
Proof Introduce an auxiliary function
119875 (119909 119905) fl minuseminus119906119906119905+ 120572
1
119886 (119906) (10)
and then we have
nabla119875 = eminus119906119906119905nabla119906 minus eminus119906nabla119906
119905minus 120572
1198861015840
1198862nabla119906 (11)
Δ119875 = minuseminus119906119906119905|nabla119906|2+ 2eminus119906nabla119906 sdot nabla119906
119905+ eminus119906119906
119905Δ119906
minus eminus119906Δ119906119905+ (2120572
(1198861015840)2
1198863minus 120572
11988610158401015840
1198862)|nabla119906|
2
minus 1205721198861015840
1198862Δ119906
(12)
119875119905= eminus119906 (119906
119905)2
minus eminus119906 (119906119905)119905minus 120572
1198861015840
1198862119906119905
= eminus119906 (119906119905)2
minus eminus119906 ( 119886
1198921015840Δ119906 +
1198861015840
1198921015840|nabla119906|2+
119891
1198921015840)119905
minus 1205721198861015840
1198862119906119905
= eminus119906 (119906119905)2
+ (11988611989210158401015840
(1198921015840)2minus
1198861015840
1198921015840) eminus119906119906
119905Δ119906
minus119886
1198921015840eminus119906Δ119906
119905+ (
119886101584011989210158401015840
(1198921015840)2minus
11988610158401015840
1198921015840) eminus119906119906
119905|nabla119906|2
minus 21198861015840
1198921015840eminus119906 (nabla119906 sdot nabla119906
119905) + (
11989111989210158401015840
(1198921015840)2minus
1198911015840
1198921015840) eminus119906119906
119905
minus 1205721198861015840
1198862119906119905
(13)
Journal of Function Spaces 3
It follows from (12) and (13) that
119886
1198921015840Δ119875 minus 119875
119905= (
11988610158401015840
1198921015840minus
119886
1198921015840minus
119886101584011989210158401015840
(1198921015840)2) eminus119906119906
119905|nabla119906|2
+ (2119886
1198921015840+ 2
1198861015840
1198921015840) eminus119906 (nabla119906 sdot nabla119906
119905)
+ (1198861015840
1198921015840+
119886
1198921015840minus
11988611989210158401015840
(1198921015840)2) eminus119906119906
119905Δ119906
+ (2120572(1198861015840)2
11988621198921015840minus 120572
11988610158401015840
1198861198921015840) |nabla119906|
2
minus 1205721198861015840
1198861198921015840Δ119906 minus eminus119906 (119906
119905)2
+ (1198911015840
1198921015840minus
11989111989210158401015840
(1198921015840)2) eminus119906119906
119905+ 120572
1198861015840
1198862119906119905
(14)
The first equation of (1) implies
Δ119906 =1198921015840
119886119906119905minus
1198861015840
119886|nabla119906|2minus
119891
119886 (15)
Inserting (15) into (14) we obtain
119886
1198921015840Δ119875 minus 119875
119905= (
11988610158401015840
1198921015840minus
119886
1198921015840minus
(1198861015840)2
1198861198921015840minus
1198861015840
1198921015840) eminus119906119906
119905|nabla119906|2
+ (2119886
1198921015840+ 2
1198861015840
1198921015840) eminus119906 (nabla119906 sdot nabla119906
119905)
+1198921015840
119886(
119886
1198921015840)
1015840
eminus119906 (119906119905)2
+ (1198911015840
1198921015840minus
1198861015840119891
1198861198921015840minus
119891
1198921015840) eminus119906119906
119905
+ (3120572(1198861015840)2
11988621198921015840minus 120572
11988610158401015840
1198861198921015840) |nabla119906|
2+ 120572
1198861015840119891
11988621198921015840
(16)
It follows from (11) that
nabla119906119905= minuse119906nabla119875 + 119906
119905nabla119906 minus 120572
1198861015840
1198862e119906nabla119906 (17)
Substituting (17) into (16) we get
119886
1198921015840Δ119875 + 2
119886 + 1198861015840
1198921015840nabla119906 sdot nabla119875 minus 119875
119905
= (11988610158401015840
1198921015840+
119886
1198921015840minus
(1198861015840)2
1198861198921015840+
1198861015840
1198921015840) eminus119906119906
119905|nabla119906|2
+ (120572(1198861015840)2
11988621198921015840minus 2120572
1198861015840
1198861198921015840minus 120572
11988610158401015840
1198861198921015840) |nabla119906|
2
+1198921015840
119886(
119886
1198921015840)
1015840
eminus119906 (119906119905)2
+ (1198911015840
1198921015840minus
1198861015840119891
1198861198921015840minus
119891
1198921015840) eminus119906119906
119905+ 120572
1198861015840119891
11988621198921015840
(18)
By (10) we have
119906119905= minuse119906119875 + 120572e119906 1
119886 (19)
Now we insert (19) into (18) to deduce
119886
1198921015840Δ119875 + 2
1198861015840 + 119886
1198921015840nabla119906 sdot nabla119875
+119886
1198921015840[1 +
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
minus119891
119886119875
minus 119875119905
= 1205721
1198861198921015840(119886 minus 119886
1015840) |nabla119906|
2+
1198921015840
119886(
119886
1198921015840)
1015840
eminus119906 (119906119905)2
+ 1205721
1198861198921015840(1198911015840minus 119891)
(20)
Assumptions (4) ensure that the right side in equality (20) isnonnegative that is
119886
1198921015840Δ119875 + 2
1198861015840 + 119886
1198921015840nabla119906 sdot nabla119875
+119886
1198921015840[1 +
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
minus119891
119886119875
minus 119875119905ge 0 in Ω times (0 119879)
(21)
4 Journal of Function Spaces
Next it follows from (1) and (10) that
120597119875
120597119899= eminus119906119906
119905
120597119906
120597119899minus eminus119906
120597119906119905
120597119899minus 120572
1198861015840
1198862120597119906
120597119899
= eminus119906119906119905119887 minus eminus119906 (120597119906
120597119899)119905
minus 1205721198861015840
1198862119887
= eminus119906119906119905119887 minus eminus119906 (119887 (119909 119906 119905))
119905minus 120572
1198861015840
1198862119887
= (119887 minus 119887119906) eminus119906119906
119905minus eminus119906119887
119905minus 120572
1198861015840
1198862119887
= (119887 minus 119887119906) (minus119875 + 120572
1
119886) minus eminus119906119887
119905minus 120572
1198861015840
1198862119887
= (119887119906minus 119887) 119875 + 120572
119886119887 minus (119886119887)119906
1198862minus eminus119906119887
119905
on 120597Ω times (0 119879)
(22)
We note that (6) implies
maxΩ
119875 (119909 0) = maxΩ
minuseminus1199060 (1199060)119905+ 120572
1
119886 (1199060)
= maxΩ
minusnabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)
e11990601198921015840 (1199060)
+ 1205721
119886 (1199060)
= maxΩ
1
119886 (1199060)(120572
minus119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
e11990601198921015840 (1199060)
) = 0
(23)
There (21)ndash(23) assumption (5) and the maximum principle[10] imply that the maximum of the function 119875 in Ω times [0T)
is zero In fact if the function 119875 takes a positive maximum atpoint (119909
0 1199050) isin 120597Ω times (0 119879) then we have
119875 (1199090 1199050) gt 0
120597119875
120597119899
10038161003816100381610038161003816100381610038161003816(1199090 1199050)gt 0 (24)
Using assumption (5) and the fact that119875(1199090 1199050) gt 0 it follows
from (22) that
120597119875
120597119899
10038161003816100381610038161003816100381610038161003816(1199090 1199050)le 0 (25)
which contradicts the second inequality in (24) Hence themaximum of the function 119875 in Ω times [0 119879) is zero Now wehave
119875 le 0 in Ω times [0 119879) (26)
that is
119886 (119906)
e119906119906119905ge 120572 (27)
At the point 1199090
isin Ω where 1199060(1199090) = 119872
0 integrating
inequality (27) from 0 to 119905 we arrive at
int119905
0
119886 (119906)
e119906119906119905d119905 = int
119906(1199090119905)
1198720
119886 (119904)
e119904d119904 ge 120572119905 (28)
Inequality (28) and assumption (7) imply that 119906(119909 119905) blowsup in finite time 119905 = 119879 Now we let 119905 rarr 119879 in (28) to deduce
119879 le1
120572int+infin
1198720
119886 (119904)
e119904d119904 (29)
For each fixed 119909 isin Ω integrating inequality (27) from 119905 to119904 (0 lt 119905 lt 119904 lt 119879) we get
119867(119906 (119909 119905)) ge 119867 (119906 (119909 119905)) minus 119867 (119906 (119909 119904))
= int+infin
119906(119909119905)
119886 (119904)
e119904d119904 minus int
+infin
119906(119909119904)
119886 (119904)
e119904d119904
= int119906(119909119904)
119906(119909119905)
119886 (119904)
e119904d119904 = int
119904
119905
119886 (119906)
e119906119906119905d119905
ge 120572 (119904 minus 119905)
(30)
In the above inequality letting 119904 rarr 119879 we obtain
119867(119906 (119909 119905)) ge 120572 (119879 minus 119905) (31)
We note that 119867 is a strictly decreasing function Hence
119906 (119909 119905) le 119867minus1
(120572 (119879 minus 119905)) (32)
The proof is complete
3 Global Solution
In this section we study what interactions among the fournonlinear mechanisms of (1) result in the global solution of(1) The main results of this section are formulated in thefollowing theorem
Theorem 2 Let 119906(119909 119905) be a solution of problem (1) Assumethat the following conditions (i)ndash(iv) are fulfilled
(i) For 119904 isin R+
119886 (119904) + 1198861015840(119904) le 0
119891 (119904) + 1198911015840(119904) le 0
(119886 (119904)
1198921015840 (119904))
1015840
le 0
(33)
(ii) For (119909 119904 119905) isin 120597Ω times R+times R+
119887 (119909 119904 119905) + 119887119904(119909 119904 119905) le 0
119886 (119904) 119887 (119909 119904 119905) + (119886 (119904) 119887 (119909 119904 119905))119904le 0
119887119905(119909 119904 119905) le 0
(34)
Journal of Function Spaces 5
(iii) Consider the following
120573 fl maxΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
gt 0 (35)
(iv) Consider the following
int+infin
1198980
119886 (119904)
eminus119904d119904 = +infin 119898
0fl minΩ
1199060(119909) (36)
Then 119906(119909 119905) must be a global solution and
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) (37)
where
119870(119910) fl int119910
1198980
119886 (119904)
eminus119904d119904 119910 ge 119898
0 (38)
and 119870 is the inverse function of 119870
Proof We consider an auxiliary function
119876 (119909 119905) fl minuse119906119906119905+ 120573
1
119886 (119906) (39)
Using the same reasoning process as that of (11)ndash(20) weobtain
119886
1198921015840Δ119876 + 2
1198861015840 minus 119886
1198921015840nabla119906 sdot nabla119876
+119886
1198921015840[1 minus
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
+119891
119886119876
minus 119876119905
= 1205731
1198861198921015840(119886 + 119886
1015840) |nabla119906|
2+
1198921015840
119886(
119886
1198921015840)
1015840
e119906 (119906119905)2
+ 1205731
1198861198921015840(1198911015840+ 119891)
(40)
Assumptions (33) imply that the right side of (40) is nonpos-itive that is
119886
1198921015840Δ119876 + 2
1198861015840 minus 119886
1198921015840nabla119906 sdot nabla119876
+119886
1198921015840[1 minus
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
+119891
119886119876
minus 119876119905le 0 in Ω times (0 119879)
(41)
By (1) and (39) we get
120597119876
120597119899= minuse119906119906
119905
120597119906
120597119899minus e119906
120597119906119905
120597119899minus 120573
1198861015840
1198862120597119906
120597119899
= minuse119906119906119905119887 minus e119906 (120597119906
120597119899)119905
minus 1205731198861015840
1198862119887
= minuse119906119906119905119887 minus e119906 (119887 (119909 119906 119905))
119905minus 120573
1198861015840
1198862119887
= minus (119887 + 119887119906) e119906119906119905minus e119906119887119905minus 120573
1198861015840
1198862119887
= (119887 + 119887119906) (119876 minus 120573
1
119886) minus e119906119887
119905minus 120573
1198861015840
1198862119887
= (119887 + 119887119906) 119876 minus 120573
119886119887 + (119886119887)119906
1198862minus e119906119887119905
on 120597Ω times (0 119879)
(42)
Assumption (35) implies
minΩ
119876 (119909 0) = minΩ
minuse1199060 (1199060)119905+ 120573
1
119886 (1199060)
= minΩ
minusnabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)
eminus11990601198921015840 (1199060)
+ 1205731
119886 (1199060)
= minΩ
1
119886 (1199060)(120573
minus119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
) = 0
(43)
It follows from (41)ndash(43) (34) and the maximum principlethat the minimum of 119876 in Ω times [0 119879) is zero Hence we havethe following inequality
119876 ge 0 in Ω times [0 119879) (44)
that is
119886 (119906)
eminus119906119906119905le 120573 (45)
For each fixed 119909 isin Ω we integrate (45) from 0 to 119905 to deduce
1
120573int119905
0
119886 (119906)
eminus119906119906119905d119905 =
1
120573int119906(119909119905)
1199060(119909)
119886 (119904)
eminus119904d119904 le 119905 (46)
Inequality (46) and assumption (36) imply that 119906 must be aglobal solution Furthermore it follows from (45) that
119870 (119906 (119909 119905)) minus 119870 (1199060(119909))
= int119906(119909119905)
1198980
119886 (119904)
eminus119904d119904 minus int
1199060(119909)
1198980
119886 (119904)
eminus119904d119904 = int
119906(119909119905)
1199060(119909)
119886 (119904)
eminus119904d119904
= int119905
0
119886 (119906)
eminus119906119906119905d119905 le 120573119905
(47)
6 Journal of Function Spaces
Since 119870 is a strictly increasing function we obtain
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) (48)
The proof is complete
4 Applications
When 119886(119906) = 1 and 119887(119909 119906 119905) = 119887(119906) the results ofTheorems 1ndash2 still hold In this sense our results extend andsupplement those obtained in [21 22]
In the following we give a few examples to demonstratethe applications of Theorems 1ndash2
Example 3 Let 119906 be a solution of the following problem
(119906
2+ e1199062)
119905
= nabla sdot (e1199062nabla119906) + e119906 in Ω times (0 119879)
120597119906
120597119899= e(34)(119906minus2) + e119906minus2+119905|119909|
2
on 120597Ω times (0 119879)
119906 (119909 0) = 1 + |119909|2 in Ω
(49)
where Ω = 119909 = (1199091 1199092 1199093) | |119909|2 = 1199092
1+ 11990922+ 11990923
lt 1 Wenote
119886 (119906) = e2119906
119892 (119906) =119906
2+ e1199062
119891 (119906) = e119906
119887 (119909 119906 119905) = e(34)(119906minus2) + e119906minus2+119905|119909|2
(50)
In order to calculate the constant 120572 we set
120596 = |119909|2 (51)
and then 0 le 120596 le 1 and
120572 = minΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
e11990601198921015840 (1199060)
= minΩ
2 [6 + 2 |119909|2+ e(12)(1+|119909|
2)]
e(12)(1+|119909|2) + 1
= min0le120596le1
2 [6 + 2120596 + e(12)(1+120596)]
e(12)(1+120596) + 1 =
2 (8 + e)1 + e
(52)
We can check that (4) (5) and (7) hold It follows fromTheorem 1 that 119906(119909 119905) blows up in a finite time 119879 and
119879 le1
120572int+infin
1198720
119886 (119904)
e119904d119904 =
1 + e2 (8 + e)
int+infin
2
eminus1199042d119904
=1 + e
e (8 + e)
119906 (119909 119905) le 119867minus1
(120572 (119879 minus 119905)) = 2 ln 1 + e(8 + e) (119879 minus 119905)
(53)
Example 4 Let 119906 be a solution of the following problem
(119906e119906)119905= nabla sdot (
eminus119906
1 + 119906nabla119906) + eminus119906 in Ω times (0 119879)
120597119906
120597119899= eminus2119906 + eminus119906minus119905|119909|
2
on 120597Ω times (0 119879)
119906 (119909 0) = 1 + |119909|2 in Ω
(54)
where Ω = 119909 = (1199091 1199092 1199093) | |119909|2 = 1199092
1+ 11990922+ 11990923lt 1 Now
we have
119886 (119906) =eminus119906
1 + 119906
119892 (119906) = 119906e119906
119891 (119906) = eminus119906
119887 (119909 119906 119905) = eminus2119906 + eminus119906minus119905|119909|2
(55)
Setting
120596 = |119909|2 (56)
we get 0 le 120596 le 1 and
120573 = maxΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
= maxΩ
16 minus 2 |119909|2minus 3 |119909|
4
e2(1+|119909|2) (2 + |119909|2)4
= max0le120596le1
16 minus 2120596 minus 31205962
e2(1+120596) (2 + 120596)4 = eminus2
(57)
We can also check that (33) (34) and (36) hold HenceTheorem 2 implies 119906 must be a global solution and
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) = (2 + |119909|
2) e119905eminus2
minus 1 (58)
Remark 5 When the functions 119886 119887 119891 and 119892 are all exponen-tial functions Theorems 1 and 2 can be used When not all ofthem are exponential functionsTheorems 1 and 2 can be usedin some special cases
Competing Interests
The author declares that there are no competing interestsregarding the publication of this paper
Acknowledgments
This work was supported by the National Natural ScienceFoundation of China (no 61473180)
References
[1] PQuittner andP Souplet Superlinear Parabolic Problems Blow-Up Global Existence and Steady States Birkhauser AdvancedTexts Birkhauser Basel Switzerland 2007
Journal of Function Spaces 7
[2] MMarras and S Vernier Piro ldquoOn global existence and boundsfor blow-up time in nonlinear parabolic problems with timedependent coefficientsrdquo Discrete and Continuous DynamicalSystems vol 2013 pp 535ndash544 2013
[3] L E Payne G A Philippin and P W Schaefer ldquoBlow-upphenomena for some nonlinear parabolic problemsrdquoNonlinearAnalysis Theory Methods amp Applications vol 69 no 10 pp3495ndash3502 2008
[4] S H Chen ldquoGlobal existence and nonexistence for some degen-erate and quasilinear parabolic systemsrdquo Journal of DifferentialEquations vol 245 no 4 pp 1112ndash1136 2008
[5] S H Chen and K MacDonald ldquoGlobal and blowup solutionsfor general quasilinear parabolic systemsrdquo Nonlinear AnalysisReal World Applications vol 14 no 1 pp 423ndash433 2013
[6] J T Ding and H J Hu ldquoBlow-up and global solutions for aclass of nonlinear reaction diffusion equations under Dirichletboundary conditionsrdquo Journal of Mathematical Analysis andApplications vol 433 no 2 Article ID 19743 pp 1718ndash17352016
[7] J T Ding and M Wang ldquoBlow-up solutions global existenceand exponential decay estimates for second order parabolicproblemsrdquo Boundary Value Problems vol 2015 no 168 16pages 2015
[8] L L Zhang ldquoBlow-up of solutions for a class of nonlinearparabolic equationsrdquo Zeitschrift fur Analysis und Ihre Anwen-dungen vol 25 no 4 pp 479ndash486 2006
[9] H Amann ldquoQuasilinear parabolic systems under nonlinearboundary conditionsrdquo Archive for Rational Mechanics andAnalysis vol 92 no 2 pp 153ndash192 1986
[10] R SperbMaximumPrinciples andTheirApplications AcademicPress New York NY USA 1981
[11] A Friedman Partial Differential Equation of Parabolic TypePrentice-Hall Englewood Cliffs NJ USA 1964
[12] J Harada ldquoNon self-similar blow-up solutions to the heat equa-tion with nonlinear boundary conditionsrdquo Nonlinear AnalysisTheory Methods amp Applications vol 102 no 2 pp 36ndash83 2014
[13] J Harada and K Mihara ldquoBlow-up rate for radially symmetricsolutions of some parabolic equations with nonlinear boundaryconditionsrdquo Journal of Differential Equations vol 253 no 5 pp1647ndash1663 2012
[14] Y Liu ldquoLower bounds for the blow-up time in a non-local reac-tion diffusion problem under nonlinear boundary conditionsrdquoMathematical and ComputerModelling vol 57 no 3-4 pp 926ndash931 2013
[15] Y Liu S G Luo and Y H Ye ldquoBlow-up phenomena for aparabolic problemwith a gradient nonlinearity under nonlinearboundary conditionsrdquo Computers ampMathematics with Applica-tions vol 65 no 8 pp 1194ndash1199 2013
[16] F S Li and J L Li ldquoGlobal existence and blow-up phenom-ena for nonlinear divergence form parabolic equations withinhomogeneous Neumann boundary conditionsrdquo Journal ofMathematical Analysis and Applications vol 385 no 2 pp1005ndash1014 2012
[17] F Liang ldquoBlow-up and global solutions for nonlinear reaction-diffusion equations with nonlinear boundary conditionrdquoApplied Mathematics and Computation vol 218 no 8 pp3993ndash3999 2011
[18] L E Payne G A Philippin and S Vernier Piro ldquoBlow-up phenomena for a semilinear heat equation with nonlinearboundary condition IIrdquoNonlinear Analysis Theory Methods ampApplications vol 73 no 4 pp 971ndash978 2010
[19] J Ding X Gao and S Li ldquoGlobal existence and blow-up prob-lems for reaction diffusion model with multiple nonlinearitiesrdquoJournal of Mathematical Analysis and Applications vol 343 no1 pp 159ndash169 2008
[20] Y W Qi M X Wang and Z J Wang ldquoExistence and non-existence of global solutions of diffusion systems with nonlin-ear boundary conditionsrdquo Proceedings of the Royal Society ofEdinburghmdashSection A Mathematics vol 134 no 6 pp 1199ndash1217 2004
[21] H L Zhang ldquoBlow-up solutions and global solutions for non-linear parabolic problemsrdquoNonlinear AnalysisTheory Methodsamp Applications vol 69 no 12 pp 4567ndash4574 2008
[22] L L Zhang N Zhang and L X Li ldquoBlow-up solutions andglobal existence for a kind of quasilinear reaction-diffusionequationsrdquo Zeitschrift fur Analysis und ihre Anwendungen vol33 no 3 pp 247ndash258 2014
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
Journal of Function Spaces 3
It follows from (12) and (13) that
119886
1198921015840Δ119875 minus 119875
119905= (
11988610158401015840
1198921015840minus
119886
1198921015840minus
119886101584011989210158401015840
(1198921015840)2) eminus119906119906
119905|nabla119906|2
+ (2119886
1198921015840+ 2
1198861015840
1198921015840) eminus119906 (nabla119906 sdot nabla119906
119905)
+ (1198861015840
1198921015840+
119886
1198921015840minus
11988611989210158401015840
(1198921015840)2) eminus119906119906
119905Δ119906
+ (2120572(1198861015840)2
11988621198921015840minus 120572
11988610158401015840
1198861198921015840) |nabla119906|
2
minus 1205721198861015840
1198861198921015840Δ119906 minus eminus119906 (119906
119905)2
+ (1198911015840
1198921015840minus
11989111989210158401015840
(1198921015840)2) eminus119906119906
119905+ 120572
1198861015840
1198862119906119905
(14)
The first equation of (1) implies
Δ119906 =1198921015840
119886119906119905minus
1198861015840
119886|nabla119906|2minus
119891
119886 (15)
Inserting (15) into (14) we obtain
119886
1198921015840Δ119875 minus 119875
119905= (
11988610158401015840
1198921015840minus
119886
1198921015840minus
(1198861015840)2
1198861198921015840minus
1198861015840
1198921015840) eminus119906119906
119905|nabla119906|2
+ (2119886
1198921015840+ 2
1198861015840
1198921015840) eminus119906 (nabla119906 sdot nabla119906
119905)
+1198921015840
119886(
119886
1198921015840)
1015840
eminus119906 (119906119905)2
+ (1198911015840
1198921015840minus
1198861015840119891
1198861198921015840minus
119891
1198921015840) eminus119906119906
119905
+ (3120572(1198861015840)2
11988621198921015840minus 120572
11988610158401015840
1198861198921015840) |nabla119906|
2+ 120572
1198861015840119891
11988621198921015840
(16)
It follows from (11) that
nabla119906119905= minuse119906nabla119875 + 119906
119905nabla119906 minus 120572
1198861015840
1198862e119906nabla119906 (17)
Substituting (17) into (16) we get
119886
1198921015840Δ119875 + 2
119886 + 1198861015840
1198921015840nabla119906 sdot nabla119875 minus 119875
119905
= (11988610158401015840
1198921015840+
119886
1198921015840minus
(1198861015840)2
1198861198921015840+
1198861015840
1198921015840) eminus119906119906
119905|nabla119906|2
+ (120572(1198861015840)2
11988621198921015840minus 2120572
1198861015840
1198861198921015840minus 120572
11988610158401015840
1198861198921015840) |nabla119906|
2
+1198921015840
119886(
119886
1198921015840)
1015840
eminus119906 (119906119905)2
+ (1198911015840
1198921015840minus
1198861015840119891
1198861198921015840minus
119891
1198921015840) eminus119906119906
119905+ 120572
1198861015840119891
11988621198921015840
(18)
By (10) we have
119906119905= minuse119906119875 + 120572e119906 1
119886 (19)
Now we insert (19) into (18) to deduce
119886
1198921015840Δ119875 + 2
1198861015840 + 119886
1198921015840nabla119906 sdot nabla119875
+119886
1198921015840[1 +
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
minus119891
119886119875
minus 119875119905
= 1205721
1198861198921015840(119886 minus 119886
1015840) |nabla119906|
2+
1198921015840
119886(
119886
1198921015840)
1015840
eminus119906 (119906119905)2
+ 1205721
1198861198921015840(1198911015840minus 119891)
(20)
Assumptions (4) ensure that the right side in equality (20) isnonnegative that is
119886
1198921015840Δ119875 + 2
1198861015840 + 119886
1198921015840nabla119906 sdot nabla119875
+119886
1198921015840[1 +
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
minus119891
119886119875
minus 119875119905ge 0 in Ω times (0 119879)
(21)
4 Journal of Function Spaces
Next it follows from (1) and (10) that
120597119875
120597119899= eminus119906119906
119905
120597119906
120597119899minus eminus119906
120597119906119905
120597119899minus 120572
1198861015840
1198862120597119906
120597119899
= eminus119906119906119905119887 minus eminus119906 (120597119906
120597119899)119905
minus 1205721198861015840
1198862119887
= eminus119906119906119905119887 minus eminus119906 (119887 (119909 119906 119905))
119905minus 120572
1198861015840
1198862119887
= (119887 minus 119887119906) eminus119906119906
119905minus eminus119906119887
119905minus 120572
1198861015840
1198862119887
= (119887 minus 119887119906) (minus119875 + 120572
1
119886) minus eminus119906119887
119905minus 120572
1198861015840
1198862119887
= (119887119906minus 119887) 119875 + 120572
119886119887 minus (119886119887)119906
1198862minus eminus119906119887
119905
on 120597Ω times (0 119879)
(22)
We note that (6) implies
maxΩ
119875 (119909 0) = maxΩ
minuseminus1199060 (1199060)119905+ 120572
1
119886 (1199060)
= maxΩ
minusnabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)
e11990601198921015840 (1199060)
+ 1205721
119886 (1199060)
= maxΩ
1
119886 (1199060)(120572
minus119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
e11990601198921015840 (1199060)
) = 0
(23)
There (21)ndash(23) assumption (5) and the maximum principle[10] imply that the maximum of the function 119875 in Ω times [0T)
is zero In fact if the function 119875 takes a positive maximum atpoint (119909
0 1199050) isin 120597Ω times (0 119879) then we have
119875 (1199090 1199050) gt 0
120597119875
120597119899
10038161003816100381610038161003816100381610038161003816(1199090 1199050)gt 0 (24)
Using assumption (5) and the fact that119875(1199090 1199050) gt 0 it follows
from (22) that
120597119875
120597119899
10038161003816100381610038161003816100381610038161003816(1199090 1199050)le 0 (25)
which contradicts the second inequality in (24) Hence themaximum of the function 119875 in Ω times [0 119879) is zero Now wehave
119875 le 0 in Ω times [0 119879) (26)
that is
119886 (119906)
e119906119906119905ge 120572 (27)
At the point 1199090
isin Ω where 1199060(1199090) = 119872
0 integrating
inequality (27) from 0 to 119905 we arrive at
int119905
0
119886 (119906)
e119906119906119905d119905 = int
119906(1199090119905)
1198720
119886 (119904)
e119904d119904 ge 120572119905 (28)
Inequality (28) and assumption (7) imply that 119906(119909 119905) blowsup in finite time 119905 = 119879 Now we let 119905 rarr 119879 in (28) to deduce
119879 le1
120572int+infin
1198720
119886 (119904)
e119904d119904 (29)
For each fixed 119909 isin Ω integrating inequality (27) from 119905 to119904 (0 lt 119905 lt 119904 lt 119879) we get
119867(119906 (119909 119905)) ge 119867 (119906 (119909 119905)) minus 119867 (119906 (119909 119904))
= int+infin
119906(119909119905)
119886 (119904)
e119904d119904 minus int
+infin
119906(119909119904)
119886 (119904)
e119904d119904
= int119906(119909119904)
119906(119909119905)
119886 (119904)
e119904d119904 = int
119904
119905
119886 (119906)
e119906119906119905d119905
ge 120572 (119904 minus 119905)
(30)
In the above inequality letting 119904 rarr 119879 we obtain
119867(119906 (119909 119905)) ge 120572 (119879 minus 119905) (31)
We note that 119867 is a strictly decreasing function Hence
119906 (119909 119905) le 119867minus1
(120572 (119879 minus 119905)) (32)
The proof is complete
3 Global Solution
In this section we study what interactions among the fournonlinear mechanisms of (1) result in the global solution of(1) The main results of this section are formulated in thefollowing theorem
Theorem 2 Let 119906(119909 119905) be a solution of problem (1) Assumethat the following conditions (i)ndash(iv) are fulfilled
(i) For 119904 isin R+
119886 (119904) + 1198861015840(119904) le 0
119891 (119904) + 1198911015840(119904) le 0
(119886 (119904)
1198921015840 (119904))
1015840
le 0
(33)
(ii) For (119909 119904 119905) isin 120597Ω times R+times R+
119887 (119909 119904 119905) + 119887119904(119909 119904 119905) le 0
119886 (119904) 119887 (119909 119904 119905) + (119886 (119904) 119887 (119909 119904 119905))119904le 0
119887119905(119909 119904 119905) le 0
(34)
Journal of Function Spaces 5
(iii) Consider the following
120573 fl maxΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
gt 0 (35)
(iv) Consider the following
int+infin
1198980
119886 (119904)
eminus119904d119904 = +infin 119898
0fl minΩ
1199060(119909) (36)
Then 119906(119909 119905) must be a global solution and
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) (37)
where
119870(119910) fl int119910
1198980
119886 (119904)
eminus119904d119904 119910 ge 119898
0 (38)
and 119870 is the inverse function of 119870
Proof We consider an auxiliary function
119876 (119909 119905) fl minuse119906119906119905+ 120573
1
119886 (119906) (39)
Using the same reasoning process as that of (11)ndash(20) weobtain
119886
1198921015840Δ119876 + 2
1198861015840 minus 119886
1198921015840nabla119906 sdot nabla119876
+119886
1198921015840[1 minus
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
+119891
119886119876
minus 119876119905
= 1205731
1198861198921015840(119886 + 119886
1015840) |nabla119906|
2+
1198921015840
119886(
119886
1198921015840)
1015840
e119906 (119906119905)2
+ 1205731
1198861198921015840(1198911015840+ 119891)
(40)
Assumptions (33) imply that the right side of (40) is nonpos-itive that is
119886
1198921015840Δ119876 + 2
1198861015840 minus 119886
1198921015840nabla119906 sdot nabla119876
+119886
1198921015840[1 minus
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
+119891
119886119876
minus 119876119905le 0 in Ω times (0 119879)
(41)
By (1) and (39) we get
120597119876
120597119899= minuse119906119906
119905
120597119906
120597119899minus e119906
120597119906119905
120597119899minus 120573
1198861015840
1198862120597119906
120597119899
= minuse119906119906119905119887 minus e119906 (120597119906
120597119899)119905
minus 1205731198861015840
1198862119887
= minuse119906119906119905119887 minus e119906 (119887 (119909 119906 119905))
119905minus 120573
1198861015840
1198862119887
= minus (119887 + 119887119906) e119906119906119905minus e119906119887119905minus 120573
1198861015840
1198862119887
= (119887 + 119887119906) (119876 minus 120573
1
119886) minus e119906119887
119905minus 120573
1198861015840
1198862119887
= (119887 + 119887119906) 119876 minus 120573
119886119887 + (119886119887)119906
1198862minus e119906119887119905
on 120597Ω times (0 119879)
(42)
Assumption (35) implies
minΩ
119876 (119909 0) = minΩ
minuse1199060 (1199060)119905+ 120573
1
119886 (1199060)
= minΩ
minusnabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)
eminus11990601198921015840 (1199060)
+ 1205731
119886 (1199060)
= minΩ
1
119886 (1199060)(120573
minus119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
) = 0
(43)
It follows from (41)ndash(43) (34) and the maximum principlethat the minimum of 119876 in Ω times [0 119879) is zero Hence we havethe following inequality
119876 ge 0 in Ω times [0 119879) (44)
that is
119886 (119906)
eminus119906119906119905le 120573 (45)
For each fixed 119909 isin Ω we integrate (45) from 0 to 119905 to deduce
1
120573int119905
0
119886 (119906)
eminus119906119906119905d119905 =
1
120573int119906(119909119905)
1199060(119909)
119886 (119904)
eminus119904d119904 le 119905 (46)
Inequality (46) and assumption (36) imply that 119906 must be aglobal solution Furthermore it follows from (45) that
119870 (119906 (119909 119905)) minus 119870 (1199060(119909))
= int119906(119909119905)
1198980
119886 (119904)
eminus119904d119904 minus int
1199060(119909)
1198980
119886 (119904)
eminus119904d119904 = int
119906(119909119905)
1199060(119909)
119886 (119904)
eminus119904d119904
= int119905
0
119886 (119906)
eminus119906119906119905d119905 le 120573119905
(47)
6 Journal of Function Spaces
Since 119870 is a strictly increasing function we obtain
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) (48)
The proof is complete
4 Applications
When 119886(119906) = 1 and 119887(119909 119906 119905) = 119887(119906) the results ofTheorems 1ndash2 still hold In this sense our results extend andsupplement those obtained in [21 22]
In the following we give a few examples to demonstratethe applications of Theorems 1ndash2
Example 3 Let 119906 be a solution of the following problem
(119906
2+ e1199062)
119905
= nabla sdot (e1199062nabla119906) + e119906 in Ω times (0 119879)
120597119906
120597119899= e(34)(119906minus2) + e119906minus2+119905|119909|
2
on 120597Ω times (0 119879)
119906 (119909 0) = 1 + |119909|2 in Ω
(49)
where Ω = 119909 = (1199091 1199092 1199093) | |119909|2 = 1199092
1+ 11990922+ 11990923
lt 1 Wenote
119886 (119906) = e2119906
119892 (119906) =119906
2+ e1199062
119891 (119906) = e119906
119887 (119909 119906 119905) = e(34)(119906minus2) + e119906minus2+119905|119909|2
(50)
In order to calculate the constant 120572 we set
120596 = |119909|2 (51)
and then 0 le 120596 le 1 and
120572 = minΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
e11990601198921015840 (1199060)
= minΩ
2 [6 + 2 |119909|2+ e(12)(1+|119909|
2)]
e(12)(1+|119909|2) + 1
= min0le120596le1
2 [6 + 2120596 + e(12)(1+120596)]
e(12)(1+120596) + 1 =
2 (8 + e)1 + e
(52)
We can check that (4) (5) and (7) hold It follows fromTheorem 1 that 119906(119909 119905) blows up in a finite time 119879 and
119879 le1
120572int+infin
1198720
119886 (119904)
e119904d119904 =
1 + e2 (8 + e)
int+infin
2
eminus1199042d119904
=1 + e
e (8 + e)
119906 (119909 119905) le 119867minus1
(120572 (119879 minus 119905)) = 2 ln 1 + e(8 + e) (119879 minus 119905)
(53)
Example 4 Let 119906 be a solution of the following problem
(119906e119906)119905= nabla sdot (
eminus119906
1 + 119906nabla119906) + eminus119906 in Ω times (0 119879)
120597119906
120597119899= eminus2119906 + eminus119906minus119905|119909|
2
on 120597Ω times (0 119879)
119906 (119909 0) = 1 + |119909|2 in Ω
(54)
where Ω = 119909 = (1199091 1199092 1199093) | |119909|2 = 1199092
1+ 11990922+ 11990923lt 1 Now
we have
119886 (119906) =eminus119906
1 + 119906
119892 (119906) = 119906e119906
119891 (119906) = eminus119906
119887 (119909 119906 119905) = eminus2119906 + eminus119906minus119905|119909|2
(55)
Setting
120596 = |119909|2 (56)
we get 0 le 120596 le 1 and
120573 = maxΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
= maxΩ
16 minus 2 |119909|2minus 3 |119909|
4
e2(1+|119909|2) (2 + |119909|2)4
= max0le120596le1
16 minus 2120596 minus 31205962
e2(1+120596) (2 + 120596)4 = eminus2
(57)
We can also check that (33) (34) and (36) hold HenceTheorem 2 implies 119906 must be a global solution and
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) = (2 + |119909|
2) e119905eminus2
minus 1 (58)
Remark 5 When the functions 119886 119887 119891 and 119892 are all exponen-tial functions Theorems 1 and 2 can be used When not all ofthem are exponential functionsTheorems 1 and 2 can be usedin some special cases
Competing Interests
The author declares that there are no competing interestsregarding the publication of this paper
Acknowledgments
This work was supported by the National Natural ScienceFoundation of China (no 61473180)
References
[1] PQuittner andP Souplet Superlinear Parabolic Problems Blow-Up Global Existence and Steady States Birkhauser AdvancedTexts Birkhauser Basel Switzerland 2007
Journal of Function Spaces 7
[2] MMarras and S Vernier Piro ldquoOn global existence and boundsfor blow-up time in nonlinear parabolic problems with timedependent coefficientsrdquo Discrete and Continuous DynamicalSystems vol 2013 pp 535ndash544 2013
[3] L E Payne G A Philippin and P W Schaefer ldquoBlow-upphenomena for some nonlinear parabolic problemsrdquoNonlinearAnalysis Theory Methods amp Applications vol 69 no 10 pp3495ndash3502 2008
[4] S H Chen ldquoGlobal existence and nonexistence for some degen-erate and quasilinear parabolic systemsrdquo Journal of DifferentialEquations vol 245 no 4 pp 1112ndash1136 2008
[5] S H Chen and K MacDonald ldquoGlobal and blowup solutionsfor general quasilinear parabolic systemsrdquo Nonlinear AnalysisReal World Applications vol 14 no 1 pp 423ndash433 2013
[6] J T Ding and H J Hu ldquoBlow-up and global solutions for aclass of nonlinear reaction diffusion equations under Dirichletboundary conditionsrdquo Journal of Mathematical Analysis andApplications vol 433 no 2 Article ID 19743 pp 1718ndash17352016
[7] J T Ding and M Wang ldquoBlow-up solutions global existenceand exponential decay estimates for second order parabolicproblemsrdquo Boundary Value Problems vol 2015 no 168 16pages 2015
[8] L L Zhang ldquoBlow-up of solutions for a class of nonlinearparabolic equationsrdquo Zeitschrift fur Analysis und Ihre Anwen-dungen vol 25 no 4 pp 479ndash486 2006
[9] H Amann ldquoQuasilinear parabolic systems under nonlinearboundary conditionsrdquo Archive for Rational Mechanics andAnalysis vol 92 no 2 pp 153ndash192 1986
[10] R SperbMaximumPrinciples andTheirApplications AcademicPress New York NY USA 1981
[11] A Friedman Partial Differential Equation of Parabolic TypePrentice-Hall Englewood Cliffs NJ USA 1964
[12] J Harada ldquoNon self-similar blow-up solutions to the heat equa-tion with nonlinear boundary conditionsrdquo Nonlinear AnalysisTheory Methods amp Applications vol 102 no 2 pp 36ndash83 2014
[13] J Harada and K Mihara ldquoBlow-up rate for radially symmetricsolutions of some parabolic equations with nonlinear boundaryconditionsrdquo Journal of Differential Equations vol 253 no 5 pp1647ndash1663 2012
[14] Y Liu ldquoLower bounds for the blow-up time in a non-local reac-tion diffusion problem under nonlinear boundary conditionsrdquoMathematical and ComputerModelling vol 57 no 3-4 pp 926ndash931 2013
[15] Y Liu S G Luo and Y H Ye ldquoBlow-up phenomena for aparabolic problemwith a gradient nonlinearity under nonlinearboundary conditionsrdquo Computers ampMathematics with Applica-tions vol 65 no 8 pp 1194ndash1199 2013
[16] F S Li and J L Li ldquoGlobal existence and blow-up phenom-ena for nonlinear divergence form parabolic equations withinhomogeneous Neumann boundary conditionsrdquo Journal ofMathematical Analysis and Applications vol 385 no 2 pp1005ndash1014 2012
[17] F Liang ldquoBlow-up and global solutions for nonlinear reaction-diffusion equations with nonlinear boundary conditionrdquoApplied Mathematics and Computation vol 218 no 8 pp3993ndash3999 2011
[18] L E Payne G A Philippin and S Vernier Piro ldquoBlow-up phenomena for a semilinear heat equation with nonlinearboundary condition IIrdquoNonlinear Analysis Theory Methods ampApplications vol 73 no 4 pp 971ndash978 2010
[19] J Ding X Gao and S Li ldquoGlobal existence and blow-up prob-lems for reaction diffusion model with multiple nonlinearitiesrdquoJournal of Mathematical Analysis and Applications vol 343 no1 pp 159ndash169 2008
[20] Y W Qi M X Wang and Z J Wang ldquoExistence and non-existence of global solutions of diffusion systems with nonlin-ear boundary conditionsrdquo Proceedings of the Royal Society ofEdinburghmdashSection A Mathematics vol 134 no 6 pp 1199ndash1217 2004
[21] H L Zhang ldquoBlow-up solutions and global solutions for non-linear parabolic problemsrdquoNonlinear AnalysisTheory Methodsamp Applications vol 69 no 12 pp 4567ndash4574 2008
[22] L L Zhang N Zhang and L X Li ldquoBlow-up solutions andglobal existence for a kind of quasilinear reaction-diffusionequationsrdquo Zeitschrift fur Analysis und ihre Anwendungen vol33 no 3 pp 247ndash258 2014
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
4 Journal of Function Spaces
Next it follows from (1) and (10) that
120597119875
120597119899= eminus119906119906
119905
120597119906
120597119899minus eminus119906
120597119906119905
120597119899minus 120572
1198861015840
1198862120597119906
120597119899
= eminus119906119906119905119887 minus eminus119906 (120597119906
120597119899)119905
minus 1205721198861015840
1198862119887
= eminus119906119906119905119887 minus eminus119906 (119887 (119909 119906 119905))
119905minus 120572
1198861015840
1198862119887
= (119887 minus 119887119906) eminus119906119906
119905minus eminus119906119887
119905minus 120572
1198861015840
1198862119887
= (119887 minus 119887119906) (minus119875 + 120572
1
119886) minus eminus119906119887
119905minus 120572
1198861015840
1198862119887
= (119887119906minus 119887) 119875 + 120572
119886119887 minus (119886119887)119906
1198862minus eminus119906119887
119905
on 120597Ω times (0 119879)
(22)
We note that (6) implies
maxΩ
119875 (119909 0) = maxΩ
minuseminus1199060 (1199060)119905+ 120572
1
119886 (1199060)
= maxΩ
minusnabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)
e11990601198921015840 (1199060)
+ 1205721
119886 (1199060)
= maxΩ
1
119886 (1199060)(120572
minus119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
e11990601198921015840 (1199060)
) = 0
(23)
There (21)ndash(23) assumption (5) and the maximum principle[10] imply that the maximum of the function 119875 in Ω times [0T)
is zero In fact if the function 119875 takes a positive maximum atpoint (119909
0 1199050) isin 120597Ω times (0 119879) then we have
119875 (1199090 1199050) gt 0
120597119875
120597119899
10038161003816100381610038161003816100381610038161003816(1199090 1199050)gt 0 (24)
Using assumption (5) and the fact that119875(1199090 1199050) gt 0 it follows
from (22) that
120597119875
120597119899
10038161003816100381610038161003816100381610038161003816(1199090 1199050)le 0 (25)
which contradicts the second inequality in (24) Hence themaximum of the function 119875 in Ω times [0 119879) is zero Now wehave
119875 le 0 in Ω times [0 119879) (26)
that is
119886 (119906)
e119906119906119905ge 120572 (27)
At the point 1199090
isin Ω where 1199060(1199090) = 119872
0 integrating
inequality (27) from 0 to 119905 we arrive at
int119905
0
119886 (119906)
e119906119906119905d119905 = int
119906(1199090119905)
1198720
119886 (119904)
e119904d119904 ge 120572119905 (28)
Inequality (28) and assumption (7) imply that 119906(119909 119905) blowsup in finite time 119905 = 119879 Now we let 119905 rarr 119879 in (28) to deduce
119879 le1
120572int+infin
1198720
119886 (119904)
e119904d119904 (29)
For each fixed 119909 isin Ω integrating inequality (27) from 119905 to119904 (0 lt 119905 lt 119904 lt 119879) we get
119867(119906 (119909 119905)) ge 119867 (119906 (119909 119905)) minus 119867 (119906 (119909 119904))
= int+infin
119906(119909119905)
119886 (119904)
e119904d119904 minus int
+infin
119906(119909119904)
119886 (119904)
e119904d119904
= int119906(119909119904)
119906(119909119905)
119886 (119904)
e119904d119904 = int
119904
119905
119886 (119906)
e119906119906119905d119905
ge 120572 (119904 minus 119905)
(30)
In the above inequality letting 119904 rarr 119879 we obtain
119867(119906 (119909 119905)) ge 120572 (119879 minus 119905) (31)
We note that 119867 is a strictly decreasing function Hence
119906 (119909 119905) le 119867minus1
(120572 (119879 minus 119905)) (32)
The proof is complete
3 Global Solution
In this section we study what interactions among the fournonlinear mechanisms of (1) result in the global solution of(1) The main results of this section are formulated in thefollowing theorem
Theorem 2 Let 119906(119909 119905) be a solution of problem (1) Assumethat the following conditions (i)ndash(iv) are fulfilled
(i) For 119904 isin R+
119886 (119904) + 1198861015840(119904) le 0
119891 (119904) + 1198911015840(119904) le 0
(119886 (119904)
1198921015840 (119904))
1015840
le 0
(33)
(ii) For (119909 119904 119905) isin 120597Ω times R+times R+
119887 (119909 119904 119905) + 119887119904(119909 119904 119905) le 0
119886 (119904) 119887 (119909 119904 119905) + (119886 (119904) 119887 (119909 119904 119905))119904le 0
119887119905(119909 119904 119905) le 0
(34)
Journal of Function Spaces 5
(iii) Consider the following
120573 fl maxΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
gt 0 (35)
(iv) Consider the following
int+infin
1198980
119886 (119904)
eminus119904d119904 = +infin 119898
0fl minΩ
1199060(119909) (36)
Then 119906(119909 119905) must be a global solution and
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) (37)
where
119870(119910) fl int119910
1198980
119886 (119904)
eminus119904d119904 119910 ge 119898
0 (38)
and 119870 is the inverse function of 119870
Proof We consider an auxiliary function
119876 (119909 119905) fl minuse119906119906119905+ 120573
1
119886 (119906) (39)
Using the same reasoning process as that of (11)ndash(20) weobtain
119886
1198921015840Δ119876 + 2
1198861015840 minus 119886
1198921015840nabla119906 sdot nabla119876
+119886
1198921015840[1 minus
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
+119891
119886119876
minus 119876119905
= 1205731
1198861198921015840(119886 + 119886
1015840) |nabla119906|
2+
1198921015840
119886(
119886
1198921015840)
1015840
e119906 (119906119905)2
+ 1205731
1198861198921015840(1198911015840+ 119891)
(40)
Assumptions (33) imply that the right side of (40) is nonpos-itive that is
119886
1198921015840Δ119876 + 2
1198861015840 minus 119886
1198921015840nabla119906 sdot nabla119876
+119886
1198921015840[1 minus
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
+119891
119886119876
minus 119876119905le 0 in Ω times (0 119879)
(41)
By (1) and (39) we get
120597119876
120597119899= minuse119906119906
119905
120597119906
120597119899minus e119906
120597119906119905
120597119899minus 120573
1198861015840
1198862120597119906
120597119899
= minuse119906119906119905119887 minus e119906 (120597119906
120597119899)119905
minus 1205731198861015840
1198862119887
= minuse119906119906119905119887 minus e119906 (119887 (119909 119906 119905))
119905minus 120573
1198861015840
1198862119887
= minus (119887 + 119887119906) e119906119906119905minus e119906119887119905minus 120573
1198861015840
1198862119887
= (119887 + 119887119906) (119876 minus 120573
1
119886) minus e119906119887
119905minus 120573
1198861015840
1198862119887
= (119887 + 119887119906) 119876 minus 120573
119886119887 + (119886119887)119906
1198862minus e119906119887119905
on 120597Ω times (0 119879)
(42)
Assumption (35) implies
minΩ
119876 (119909 0) = minΩ
minuse1199060 (1199060)119905+ 120573
1
119886 (1199060)
= minΩ
minusnabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)
eminus11990601198921015840 (1199060)
+ 1205731
119886 (1199060)
= minΩ
1
119886 (1199060)(120573
minus119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
) = 0
(43)
It follows from (41)ndash(43) (34) and the maximum principlethat the minimum of 119876 in Ω times [0 119879) is zero Hence we havethe following inequality
119876 ge 0 in Ω times [0 119879) (44)
that is
119886 (119906)
eminus119906119906119905le 120573 (45)
For each fixed 119909 isin Ω we integrate (45) from 0 to 119905 to deduce
1
120573int119905
0
119886 (119906)
eminus119906119906119905d119905 =
1
120573int119906(119909119905)
1199060(119909)
119886 (119904)
eminus119904d119904 le 119905 (46)
Inequality (46) and assumption (36) imply that 119906 must be aglobal solution Furthermore it follows from (45) that
119870 (119906 (119909 119905)) minus 119870 (1199060(119909))
= int119906(119909119905)
1198980
119886 (119904)
eminus119904d119904 minus int
1199060(119909)
1198980
119886 (119904)
eminus119904d119904 = int
119906(119909119905)
1199060(119909)
119886 (119904)
eminus119904d119904
= int119905
0
119886 (119906)
eminus119906119906119905d119905 le 120573119905
(47)
6 Journal of Function Spaces
Since 119870 is a strictly increasing function we obtain
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) (48)
The proof is complete
4 Applications
When 119886(119906) = 1 and 119887(119909 119906 119905) = 119887(119906) the results ofTheorems 1ndash2 still hold In this sense our results extend andsupplement those obtained in [21 22]
In the following we give a few examples to demonstratethe applications of Theorems 1ndash2
Example 3 Let 119906 be a solution of the following problem
(119906
2+ e1199062)
119905
= nabla sdot (e1199062nabla119906) + e119906 in Ω times (0 119879)
120597119906
120597119899= e(34)(119906minus2) + e119906minus2+119905|119909|
2
on 120597Ω times (0 119879)
119906 (119909 0) = 1 + |119909|2 in Ω
(49)
where Ω = 119909 = (1199091 1199092 1199093) | |119909|2 = 1199092
1+ 11990922+ 11990923
lt 1 Wenote
119886 (119906) = e2119906
119892 (119906) =119906
2+ e1199062
119891 (119906) = e119906
119887 (119909 119906 119905) = e(34)(119906minus2) + e119906minus2+119905|119909|2
(50)
In order to calculate the constant 120572 we set
120596 = |119909|2 (51)
and then 0 le 120596 le 1 and
120572 = minΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
e11990601198921015840 (1199060)
= minΩ
2 [6 + 2 |119909|2+ e(12)(1+|119909|
2)]
e(12)(1+|119909|2) + 1
= min0le120596le1
2 [6 + 2120596 + e(12)(1+120596)]
e(12)(1+120596) + 1 =
2 (8 + e)1 + e
(52)
We can check that (4) (5) and (7) hold It follows fromTheorem 1 that 119906(119909 119905) blows up in a finite time 119879 and
119879 le1
120572int+infin
1198720
119886 (119904)
e119904d119904 =
1 + e2 (8 + e)
int+infin
2
eminus1199042d119904
=1 + e
e (8 + e)
119906 (119909 119905) le 119867minus1
(120572 (119879 minus 119905)) = 2 ln 1 + e(8 + e) (119879 minus 119905)
(53)
Example 4 Let 119906 be a solution of the following problem
(119906e119906)119905= nabla sdot (
eminus119906
1 + 119906nabla119906) + eminus119906 in Ω times (0 119879)
120597119906
120597119899= eminus2119906 + eminus119906minus119905|119909|
2
on 120597Ω times (0 119879)
119906 (119909 0) = 1 + |119909|2 in Ω
(54)
where Ω = 119909 = (1199091 1199092 1199093) | |119909|2 = 1199092
1+ 11990922+ 11990923lt 1 Now
we have
119886 (119906) =eminus119906
1 + 119906
119892 (119906) = 119906e119906
119891 (119906) = eminus119906
119887 (119909 119906 119905) = eminus2119906 + eminus119906minus119905|119909|2
(55)
Setting
120596 = |119909|2 (56)
we get 0 le 120596 le 1 and
120573 = maxΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
= maxΩ
16 minus 2 |119909|2minus 3 |119909|
4
e2(1+|119909|2) (2 + |119909|2)4
= max0le120596le1
16 minus 2120596 minus 31205962
e2(1+120596) (2 + 120596)4 = eminus2
(57)
We can also check that (33) (34) and (36) hold HenceTheorem 2 implies 119906 must be a global solution and
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) = (2 + |119909|
2) e119905eminus2
minus 1 (58)
Remark 5 When the functions 119886 119887 119891 and 119892 are all exponen-tial functions Theorems 1 and 2 can be used When not all ofthem are exponential functionsTheorems 1 and 2 can be usedin some special cases
Competing Interests
The author declares that there are no competing interestsregarding the publication of this paper
Acknowledgments
This work was supported by the National Natural ScienceFoundation of China (no 61473180)
References
[1] PQuittner andP Souplet Superlinear Parabolic Problems Blow-Up Global Existence and Steady States Birkhauser AdvancedTexts Birkhauser Basel Switzerland 2007
Journal of Function Spaces 7
[2] MMarras and S Vernier Piro ldquoOn global existence and boundsfor blow-up time in nonlinear parabolic problems with timedependent coefficientsrdquo Discrete and Continuous DynamicalSystems vol 2013 pp 535ndash544 2013
[3] L E Payne G A Philippin and P W Schaefer ldquoBlow-upphenomena for some nonlinear parabolic problemsrdquoNonlinearAnalysis Theory Methods amp Applications vol 69 no 10 pp3495ndash3502 2008
[4] S H Chen ldquoGlobal existence and nonexistence for some degen-erate and quasilinear parabolic systemsrdquo Journal of DifferentialEquations vol 245 no 4 pp 1112ndash1136 2008
[5] S H Chen and K MacDonald ldquoGlobal and blowup solutionsfor general quasilinear parabolic systemsrdquo Nonlinear AnalysisReal World Applications vol 14 no 1 pp 423ndash433 2013
[6] J T Ding and H J Hu ldquoBlow-up and global solutions for aclass of nonlinear reaction diffusion equations under Dirichletboundary conditionsrdquo Journal of Mathematical Analysis andApplications vol 433 no 2 Article ID 19743 pp 1718ndash17352016
[7] J T Ding and M Wang ldquoBlow-up solutions global existenceand exponential decay estimates for second order parabolicproblemsrdquo Boundary Value Problems vol 2015 no 168 16pages 2015
[8] L L Zhang ldquoBlow-up of solutions for a class of nonlinearparabolic equationsrdquo Zeitschrift fur Analysis und Ihre Anwen-dungen vol 25 no 4 pp 479ndash486 2006
[9] H Amann ldquoQuasilinear parabolic systems under nonlinearboundary conditionsrdquo Archive for Rational Mechanics andAnalysis vol 92 no 2 pp 153ndash192 1986
[10] R SperbMaximumPrinciples andTheirApplications AcademicPress New York NY USA 1981
[11] A Friedman Partial Differential Equation of Parabolic TypePrentice-Hall Englewood Cliffs NJ USA 1964
[12] J Harada ldquoNon self-similar blow-up solutions to the heat equa-tion with nonlinear boundary conditionsrdquo Nonlinear AnalysisTheory Methods amp Applications vol 102 no 2 pp 36ndash83 2014
[13] J Harada and K Mihara ldquoBlow-up rate for radially symmetricsolutions of some parabolic equations with nonlinear boundaryconditionsrdquo Journal of Differential Equations vol 253 no 5 pp1647ndash1663 2012
[14] Y Liu ldquoLower bounds for the blow-up time in a non-local reac-tion diffusion problem under nonlinear boundary conditionsrdquoMathematical and ComputerModelling vol 57 no 3-4 pp 926ndash931 2013
[15] Y Liu S G Luo and Y H Ye ldquoBlow-up phenomena for aparabolic problemwith a gradient nonlinearity under nonlinearboundary conditionsrdquo Computers ampMathematics with Applica-tions vol 65 no 8 pp 1194ndash1199 2013
[16] F S Li and J L Li ldquoGlobal existence and blow-up phenom-ena for nonlinear divergence form parabolic equations withinhomogeneous Neumann boundary conditionsrdquo Journal ofMathematical Analysis and Applications vol 385 no 2 pp1005ndash1014 2012
[17] F Liang ldquoBlow-up and global solutions for nonlinear reaction-diffusion equations with nonlinear boundary conditionrdquoApplied Mathematics and Computation vol 218 no 8 pp3993ndash3999 2011
[18] L E Payne G A Philippin and S Vernier Piro ldquoBlow-up phenomena for a semilinear heat equation with nonlinearboundary condition IIrdquoNonlinear Analysis Theory Methods ampApplications vol 73 no 4 pp 971ndash978 2010
[19] J Ding X Gao and S Li ldquoGlobal existence and blow-up prob-lems for reaction diffusion model with multiple nonlinearitiesrdquoJournal of Mathematical Analysis and Applications vol 343 no1 pp 159ndash169 2008
[20] Y W Qi M X Wang and Z J Wang ldquoExistence and non-existence of global solutions of diffusion systems with nonlin-ear boundary conditionsrdquo Proceedings of the Royal Society ofEdinburghmdashSection A Mathematics vol 134 no 6 pp 1199ndash1217 2004
[21] H L Zhang ldquoBlow-up solutions and global solutions for non-linear parabolic problemsrdquoNonlinear AnalysisTheory Methodsamp Applications vol 69 no 12 pp 4567ndash4574 2008
[22] L L Zhang N Zhang and L X Li ldquoBlow-up solutions andglobal existence for a kind of quasilinear reaction-diffusionequationsrdquo Zeitschrift fur Analysis und ihre Anwendungen vol33 no 3 pp 247ndash258 2014
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
Journal of Function Spaces 5
(iii) Consider the following
120573 fl maxΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
gt 0 (35)
(iv) Consider the following
int+infin
1198980
119886 (119904)
eminus119904d119904 = +infin 119898
0fl minΩ
1199060(119909) (36)
Then 119906(119909 119905) must be a global solution and
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) (37)
where
119870(119910) fl int119910
1198980
119886 (119904)
eminus119904d119904 119910 ge 119898
0 (38)
and 119870 is the inverse function of 119870
Proof We consider an auxiliary function
119876 (119909 119905) fl minuse119906119906119905+ 120573
1
119886 (119906) (39)
Using the same reasoning process as that of (11)ndash(20) weobtain
119886
1198921015840Δ119876 + 2
1198861015840 minus 119886
1198921015840nabla119906 sdot nabla119876
+119886
1198921015840[1 minus
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
+119891
119886119876
minus 119876119905
= 1205731
1198861198921015840(119886 + 119886
1015840) |nabla119906|
2+
1198921015840
119886(
119886
1198921015840)
1015840
e119906 (119906119905)2
+ 1205731
1198861198921015840(1198911015840+ 119891)
(40)
Assumptions (33) imply that the right side of (40) is nonpos-itive that is
119886
1198921015840Δ119876 + 2
1198861015840 minus 119886
1198921015840nabla119906 sdot nabla119876
+119886
1198921015840[1 minus
1198861015840
119886+ (
1198861015840
119886)
1015840
] |nabla119906|2+ (
119891
119886)
1015840
+119891
119886119876
minus 119876119905le 0 in Ω times (0 119879)
(41)
By (1) and (39) we get
120597119876
120597119899= minuse119906119906
119905
120597119906
120597119899minus e119906
120597119906119905
120597119899minus 120573
1198861015840
1198862120597119906
120597119899
= minuse119906119906119905119887 minus e119906 (120597119906
120597119899)119905
minus 1205731198861015840
1198862119887
= minuse119906119906119905119887 minus e119906 (119887 (119909 119906 119905))
119905minus 120573
1198861015840
1198862119887
= minus (119887 + 119887119906) e119906119906119905minus e119906119887119905minus 120573
1198861015840
1198862119887
= (119887 + 119887119906) (119876 minus 120573
1
119886) minus e119906119887
119905minus 120573
1198861015840
1198862119887
= (119887 + 119887119906) 119876 minus 120573
119886119887 + (119886119887)119906
1198862minus e119906119887119905
on 120597Ω times (0 119879)
(42)
Assumption (35) implies
minΩ
119876 (119909 0) = minΩ
minuse1199060 (1199060)119905+ 120573
1
119886 (1199060)
= minΩ
minusnabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)
eminus11990601198921015840 (1199060)
+ 1205731
119886 (1199060)
= minΩ
1
119886 (1199060)(120573
minus119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
) = 0
(43)
It follows from (41)ndash(43) (34) and the maximum principlethat the minimum of 119876 in Ω times [0 119879) is zero Hence we havethe following inequality
119876 ge 0 in Ω times [0 119879) (44)
that is
119886 (119906)
eminus119906119906119905le 120573 (45)
For each fixed 119909 isin Ω we integrate (45) from 0 to 119905 to deduce
1
120573int119905
0
119886 (119906)
eminus119906119906119905d119905 =
1
120573int119906(119909119905)
1199060(119909)
119886 (119904)
eminus119904d119904 le 119905 (46)
Inequality (46) and assumption (36) imply that 119906 must be aglobal solution Furthermore it follows from (45) that
119870 (119906 (119909 119905)) minus 119870 (1199060(119909))
= int119906(119909119905)
1198980
119886 (119904)
eminus119904d119904 minus int
1199060(119909)
1198980
119886 (119904)
eminus119904d119904 = int
119906(119909119905)
1199060(119909)
119886 (119904)
eminus119904d119904
= int119905
0
119886 (119906)
eminus119906119906119905d119905 le 120573119905
(47)
6 Journal of Function Spaces
Since 119870 is a strictly increasing function we obtain
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) (48)
The proof is complete
4 Applications
When 119886(119906) = 1 and 119887(119909 119906 119905) = 119887(119906) the results ofTheorems 1ndash2 still hold In this sense our results extend andsupplement those obtained in [21 22]
In the following we give a few examples to demonstratethe applications of Theorems 1ndash2
Example 3 Let 119906 be a solution of the following problem
(119906
2+ e1199062)
119905
= nabla sdot (e1199062nabla119906) + e119906 in Ω times (0 119879)
120597119906
120597119899= e(34)(119906minus2) + e119906minus2+119905|119909|
2
on 120597Ω times (0 119879)
119906 (119909 0) = 1 + |119909|2 in Ω
(49)
where Ω = 119909 = (1199091 1199092 1199093) | |119909|2 = 1199092
1+ 11990922+ 11990923
lt 1 Wenote
119886 (119906) = e2119906
119892 (119906) =119906
2+ e1199062
119891 (119906) = e119906
119887 (119909 119906 119905) = e(34)(119906minus2) + e119906minus2+119905|119909|2
(50)
In order to calculate the constant 120572 we set
120596 = |119909|2 (51)
and then 0 le 120596 le 1 and
120572 = minΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
e11990601198921015840 (1199060)
= minΩ
2 [6 + 2 |119909|2+ e(12)(1+|119909|
2)]
e(12)(1+|119909|2) + 1
= min0le120596le1
2 [6 + 2120596 + e(12)(1+120596)]
e(12)(1+120596) + 1 =
2 (8 + e)1 + e
(52)
We can check that (4) (5) and (7) hold It follows fromTheorem 1 that 119906(119909 119905) blows up in a finite time 119879 and
119879 le1
120572int+infin
1198720
119886 (119904)
e119904d119904 =
1 + e2 (8 + e)
int+infin
2
eminus1199042d119904
=1 + e
e (8 + e)
119906 (119909 119905) le 119867minus1
(120572 (119879 minus 119905)) = 2 ln 1 + e(8 + e) (119879 minus 119905)
(53)
Example 4 Let 119906 be a solution of the following problem
(119906e119906)119905= nabla sdot (
eminus119906
1 + 119906nabla119906) + eminus119906 in Ω times (0 119879)
120597119906
120597119899= eminus2119906 + eminus119906minus119905|119909|
2
on 120597Ω times (0 119879)
119906 (119909 0) = 1 + |119909|2 in Ω
(54)
where Ω = 119909 = (1199091 1199092 1199093) | |119909|2 = 1199092
1+ 11990922+ 11990923lt 1 Now
we have
119886 (119906) =eminus119906
1 + 119906
119892 (119906) = 119906e119906
119891 (119906) = eminus119906
119887 (119909 119906 119905) = eminus2119906 + eminus119906minus119905|119909|2
(55)
Setting
120596 = |119909|2 (56)
we get 0 le 120596 le 1 and
120573 = maxΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
= maxΩ
16 minus 2 |119909|2minus 3 |119909|
4
e2(1+|119909|2) (2 + |119909|2)4
= max0le120596le1
16 minus 2120596 minus 31205962
e2(1+120596) (2 + 120596)4 = eminus2
(57)
We can also check that (33) (34) and (36) hold HenceTheorem 2 implies 119906 must be a global solution and
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) = (2 + |119909|
2) e119905eminus2
minus 1 (58)
Remark 5 When the functions 119886 119887 119891 and 119892 are all exponen-tial functions Theorems 1 and 2 can be used When not all ofthem are exponential functionsTheorems 1 and 2 can be usedin some special cases
Competing Interests
The author declares that there are no competing interestsregarding the publication of this paper
Acknowledgments
This work was supported by the National Natural ScienceFoundation of China (no 61473180)
References
[1] PQuittner andP Souplet Superlinear Parabolic Problems Blow-Up Global Existence and Steady States Birkhauser AdvancedTexts Birkhauser Basel Switzerland 2007
Journal of Function Spaces 7
[2] MMarras and S Vernier Piro ldquoOn global existence and boundsfor blow-up time in nonlinear parabolic problems with timedependent coefficientsrdquo Discrete and Continuous DynamicalSystems vol 2013 pp 535ndash544 2013
[3] L E Payne G A Philippin and P W Schaefer ldquoBlow-upphenomena for some nonlinear parabolic problemsrdquoNonlinearAnalysis Theory Methods amp Applications vol 69 no 10 pp3495ndash3502 2008
[4] S H Chen ldquoGlobal existence and nonexistence for some degen-erate and quasilinear parabolic systemsrdquo Journal of DifferentialEquations vol 245 no 4 pp 1112ndash1136 2008
[5] S H Chen and K MacDonald ldquoGlobal and blowup solutionsfor general quasilinear parabolic systemsrdquo Nonlinear AnalysisReal World Applications vol 14 no 1 pp 423ndash433 2013
[6] J T Ding and H J Hu ldquoBlow-up and global solutions for aclass of nonlinear reaction diffusion equations under Dirichletboundary conditionsrdquo Journal of Mathematical Analysis andApplications vol 433 no 2 Article ID 19743 pp 1718ndash17352016
[7] J T Ding and M Wang ldquoBlow-up solutions global existenceand exponential decay estimates for second order parabolicproblemsrdquo Boundary Value Problems vol 2015 no 168 16pages 2015
[8] L L Zhang ldquoBlow-up of solutions for a class of nonlinearparabolic equationsrdquo Zeitschrift fur Analysis und Ihre Anwen-dungen vol 25 no 4 pp 479ndash486 2006
[9] H Amann ldquoQuasilinear parabolic systems under nonlinearboundary conditionsrdquo Archive for Rational Mechanics andAnalysis vol 92 no 2 pp 153ndash192 1986
[10] R SperbMaximumPrinciples andTheirApplications AcademicPress New York NY USA 1981
[11] A Friedman Partial Differential Equation of Parabolic TypePrentice-Hall Englewood Cliffs NJ USA 1964
[12] J Harada ldquoNon self-similar blow-up solutions to the heat equa-tion with nonlinear boundary conditionsrdquo Nonlinear AnalysisTheory Methods amp Applications vol 102 no 2 pp 36ndash83 2014
[13] J Harada and K Mihara ldquoBlow-up rate for radially symmetricsolutions of some parabolic equations with nonlinear boundaryconditionsrdquo Journal of Differential Equations vol 253 no 5 pp1647ndash1663 2012
[14] Y Liu ldquoLower bounds for the blow-up time in a non-local reac-tion diffusion problem under nonlinear boundary conditionsrdquoMathematical and ComputerModelling vol 57 no 3-4 pp 926ndash931 2013
[15] Y Liu S G Luo and Y H Ye ldquoBlow-up phenomena for aparabolic problemwith a gradient nonlinearity under nonlinearboundary conditionsrdquo Computers ampMathematics with Applica-tions vol 65 no 8 pp 1194ndash1199 2013
[16] F S Li and J L Li ldquoGlobal existence and blow-up phenom-ena for nonlinear divergence form parabolic equations withinhomogeneous Neumann boundary conditionsrdquo Journal ofMathematical Analysis and Applications vol 385 no 2 pp1005ndash1014 2012
[17] F Liang ldquoBlow-up and global solutions for nonlinear reaction-diffusion equations with nonlinear boundary conditionrdquoApplied Mathematics and Computation vol 218 no 8 pp3993ndash3999 2011
[18] L E Payne G A Philippin and S Vernier Piro ldquoBlow-up phenomena for a semilinear heat equation with nonlinearboundary condition IIrdquoNonlinear Analysis Theory Methods ampApplications vol 73 no 4 pp 971ndash978 2010
[19] J Ding X Gao and S Li ldquoGlobal existence and blow-up prob-lems for reaction diffusion model with multiple nonlinearitiesrdquoJournal of Mathematical Analysis and Applications vol 343 no1 pp 159ndash169 2008
[20] Y W Qi M X Wang and Z J Wang ldquoExistence and non-existence of global solutions of diffusion systems with nonlin-ear boundary conditionsrdquo Proceedings of the Royal Society ofEdinburghmdashSection A Mathematics vol 134 no 6 pp 1199ndash1217 2004
[21] H L Zhang ldquoBlow-up solutions and global solutions for non-linear parabolic problemsrdquoNonlinear AnalysisTheory Methodsamp Applications vol 69 no 12 pp 4567ndash4574 2008
[22] L L Zhang N Zhang and L X Li ldquoBlow-up solutions andglobal existence for a kind of quasilinear reaction-diffusionequationsrdquo Zeitschrift fur Analysis und ihre Anwendungen vol33 no 3 pp 247ndash258 2014
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
6 Journal of Function Spaces
Since 119870 is a strictly increasing function we obtain
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) (48)
The proof is complete
4 Applications
When 119886(119906) = 1 and 119887(119909 119906 119905) = 119887(119906) the results ofTheorems 1ndash2 still hold In this sense our results extend andsupplement those obtained in [21 22]
In the following we give a few examples to demonstratethe applications of Theorems 1ndash2
Example 3 Let 119906 be a solution of the following problem
(119906
2+ e1199062)
119905
= nabla sdot (e1199062nabla119906) + e119906 in Ω times (0 119879)
120597119906
120597119899= e(34)(119906minus2) + e119906minus2+119905|119909|
2
on 120597Ω times (0 119879)
119906 (119909 0) = 1 + |119909|2 in Ω
(49)
where Ω = 119909 = (1199091 1199092 1199093) | |119909|2 = 1199092
1+ 11990922+ 11990923
lt 1 Wenote
119886 (119906) = e2119906
119892 (119906) =119906
2+ e1199062
119891 (119906) = e119906
119887 (119909 119906 119905) = e(34)(119906minus2) + e119906minus2+119905|119909|2
(50)
In order to calculate the constant 120572 we set
120596 = |119909|2 (51)
and then 0 le 120596 le 1 and
120572 = minΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
e11990601198921015840 (1199060)
= minΩ
2 [6 + 2 |119909|2+ e(12)(1+|119909|
2)]
e(12)(1+|119909|2) + 1
= min0le120596le1
2 [6 + 2120596 + e(12)(1+120596)]
e(12)(1+120596) + 1 =
2 (8 + e)1 + e
(52)
We can check that (4) (5) and (7) hold It follows fromTheorem 1 that 119906(119909 119905) blows up in a finite time 119879 and
119879 le1
120572int+infin
1198720
119886 (119904)
e119904d119904 =
1 + e2 (8 + e)
int+infin
2
eminus1199042d119904
=1 + e
e (8 + e)
119906 (119909 119905) le 119867minus1
(120572 (119879 minus 119905)) = 2 ln 1 + e(8 + e) (119879 minus 119905)
(53)
Example 4 Let 119906 be a solution of the following problem
(119906e119906)119905= nabla sdot (
eminus119906
1 + 119906nabla119906) + eminus119906 in Ω times (0 119879)
120597119906
120597119899= eminus2119906 + eminus119906minus119905|119909|
2
on 120597Ω times (0 119879)
119906 (119909 0) = 1 + |119909|2 in Ω
(54)
where Ω = 119909 = (1199091 1199092 1199093) | |119909|2 = 1199092
1+ 11990922+ 11990923lt 1 Now
we have
119886 (119906) =eminus119906
1 + 119906
119892 (119906) = 119906e119906
119891 (119906) = eminus119906
119887 (119909 119906 119905) = eminus2119906 + eminus119906minus119905|119909|2
(55)
Setting
120596 = |119909|2 (56)
we get 0 le 120596 le 1 and
120573 = maxΩ
119886 (1199060) [nabla sdot (119886 (119906
0) nabla1199060) + 119891 (119906
0)]
eminus11990601198921015840 (1199060)
= maxΩ
16 minus 2 |119909|2minus 3 |119909|
4
e2(1+|119909|2) (2 + |119909|2)4
= max0le120596le1
16 minus 2120596 minus 31205962
e2(1+120596) (2 + 120596)4 = eminus2
(57)
We can also check that (33) (34) and (36) hold HenceTheorem 2 implies 119906 must be a global solution and
119906 (119909 119905) le 119870minus1
(120573119905 + 119870 (1199060(119909))) = (2 + |119909|
2) e119905eminus2
minus 1 (58)
Remark 5 When the functions 119886 119887 119891 and 119892 are all exponen-tial functions Theorems 1 and 2 can be used When not all ofthem are exponential functionsTheorems 1 and 2 can be usedin some special cases
Competing Interests
The author declares that there are no competing interestsregarding the publication of this paper
Acknowledgments
This work was supported by the National Natural ScienceFoundation of China (no 61473180)
References
[1] PQuittner andP Souplet Superlinear Parabolic Problems Blow-Up Global Existence and Steady States Birkhauser AdvancedTexts Birkhauser Basel Switzerland 2007
Journal of Function Spaces 7
[2] MMarras and S Vernier Piro ldquoOn global existence and boundsfor blow-up time in nonlinear parabolic problems with timedependent coefficientsrdquo Discrete and Continuous DynamicalSystems vol 2013 pp 535ndash544 2013
[3] L E Payne G A Philippin and P W Schaefer ldquoBlow-upphenomena for some nonlinear parabolic problemsrdquoNonlinearAnalysis Theory Methods amp Applications vol 69 no 10 pp3495ndash3502 2008
[4] S H Chen ldquoGlobal existence and nonexistence for some degen-erate and quasilinear parabolic systemsrdquo Journal of DifferentialEquations vol 245 no 4 pp 1112ndash1136 2008
[5] S H Chen and K MacDonald ldquoGlobal and blowup solutionsfor general quasilinear parabolic systemsrdquo Nonlinear AnalysisReal World Applications vol 14 no 1 pp 423ndash433 2013
[6] J T Ding and H J Hu ldquoBlow-up and global solutions for aclass of nonlinear reaction diffusion equations under Dirichletboundary conditionsrdquo Journal of Mathematical Analysis andApplications vol 433 no 2 Article ID 19743 pp 1718ndash17352016
[7] J T Ding and M Wang ldquoBlow-up solutions global existenceand exponential decay estimates for second order parabolicproblemsrdquo Boundary Value Problems vol 2015 no 168 16pages 2015
[8] L L Zhang ldquoBlow-up of solutions for a class of nonlinearparabolic equationsrdquo Zeitschrift fur Analysis und Ihre Anwen-dungen vol 25 no 4 pp 479ndash486 2006
[9] H Amann ldquoQuasilinear parabolic systems under nonlinearboundary conditionsrdquo Archive for Rational Mechanics andAnalysis vol 92 no 2 pp 153ndash192 1986
[10] R SperbMaximumPrinciples andTheirApplications AcademicPress New York NY USA 1981
[11] A Friedman Partial Differential Equation of Parabolic TypePrentice-Hall Englewood Cliffs NJ USA 1964
[12] J Harada ldquoNon self-similar blow-up solutions to the heat equa-tion with nonlinear boundary conditionsrdquo Nonlinear AnalysisTheory Methods amp Applications vol 102 no 2 pp 36ndash83 2014
[13] J Harada and K Mihara ldquoBlow-up rate for radially symmetricsolutions of some parabolic equations with nonlinear boundaryconditionsrdquo Journal of Differential Equations vol 253 no 5 pp1647ndash1663 2012
[14] Y Liu ldquoLower bounds for the blow-up time in a non-local reac-tion diffusion problem under nonlinear boundary conditionsrdquoMathematical and ComputerModelling vol 57 no 3-4 pp 926ndash931 2013
[15] Y Liu S G Luo and Y H Ye ldquoBlow-up phenomena for aparabolic problemwith a gradient nonlinearity under nonlinearboundary conditionsrdquo Computers ampMathematics with Applica-tions vol 65 no 8 pp 1194ndash1199 2013
[16] F S Li and J L Li ldquoGlobal existence and blow-up phenom-ena for nonlinear divergence form parabolic equations withinhomogeneous Neumann boundary conditionsrdquo Journal ofMathematical Analysis and Applications vol 385 no 2 pp1005ndash1014 2012
[17] F Liang ldquoBlow-up and global solutions for nonlinear reaction-diffusion equations with nonlinear boundary conditionrdquoApplied Mathematics and Computation vol 218 no 8 pp3993ndash3999 2011
[18] L E Payne G A Philippin and S Vernier Piro ldquoBlow-up phenomena for a semilinear heat equation with nonlinearboundary condition IIrdquoNonlinear Analysis Theory Methods ampApplications vol 73 no 4 pp 971ndash978 2010
[19] J Ding X Gao and S Li ldquoGlobal existence and blow-up prob-lems for reaction diffusion model with multiple nonlinearitiesrdquoJournal of Mathematical Analysis and Applications vol 343 no1 pp 159ndash169 2008
[20] Y W Qi M X Wang and Z J Wang ldquoExistence and non-existence of global solutions of diffusion systems with nonlin-ear boundary conditionsrdquo Proceedings of the Royal Society ofEdinburghmdashSection A Mathematics vol 134 no 6 pp 1199ndash1217 2004
[21] H L Zhang ldquoBlow-up solutions and global solutions for non-linear parabolic problemsrdquoNonlinear AnalysisTheory Methodsamp Applications vol 69 no 12 pp 4567ndash4574 2008
[22] L L Zhang N Zhang and L X Li ldquoBlow-up solutions andglobal existence for a kind of quasilinear reaction-diffusionequationsrdquo Zeitschrift fur Analysis und ihre Anwendungen vol33 no 3 pp 247ndash258 2014
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
Journal of Function Spaces 7
[2] MMarras and S Vernier Piro ldquoOn global existence and boundsfor blow-up time in nonlinear parabolic problems with timedependent coefficientsrdquo Discrete and Continuous DynamicalSystems vol 2013 pp 535ndash544 2013
[3] L E Payne G A Philippin and P W Schaefer ldquoBlow-upphenomena for some nonlinear parabolic problemsrdquoNonlinearAnalysis Theory Methods amp Applications vol 69 no 10 pp3495ndash3502 2008
[4] S H Chen ldquoGlobal existence and nonexistence for some degen-erate and quasilinear parabolic systemsrdquo Journal of DifferentialEquations vol 245 no 4 pp 1112ndash1136 2008
[5] S H Chen and K MacDonald ldquoGlobal and blowup solutionsfor general quasilinear parabolic systemsrdquo Nonlinear AnalysisReal World Applications vol 14 no 1 pp 423ndash433 2013
[6] J T Ding and H J Hu ldquoBlow-up and global solutions for aclass of nonlinear reaction diffusion equations under Dirichletboundary conditionsrdquo Journal of Mathematical Analysis andApplications vol 433 no 2 Article ID 19743 pp 1718ndash17352016
[7] J T Ding and M Wang ldquoBlow-up solutions global existenceand exponential decay estimates for second order parabolicproblemsrdquo Boundary Value Problems vol 2015 no 168 16pages 2015
[8] L L Zhang ldquoBlow-up of solutions for a class of nonlinearparabolic equationsrdquo Zeitschrift fur Analysis und Ihre Anwen-dungen vol 25 no 4 pp 479ndash486 2006
[9] H Amann ldquoQuasilinear parabolic systems under nonlinearboundary conditionsrdquo Archive for Rational Mechanics andAnalysis vol 92 no 2 pp 153ndash192 1986
[10] R SperbMaximumPrinciples andTheirApplications AcademicPress New York NY USA 1981
[11] A Friedman Partial Differential Equation of Parabolic TypePrentice-Hall Englewood Cliffs NJ USA 1964
[12] J Harada ldquoNon self-similar blow-up solutions to the heat equa-tion with nonlinear boundary conditionsrdquo Nonlinear AnalysisTheory Methods amp Applications vol 102 no 2 pp 36ndash83 2014
[13] J Harada and K Mihara ldquoBlow-up rate for radially symmetricsolutions of some parabolic equations with nonlinear boundaryconditionsrdquo Journal of Differential Equations vol 253 no 5 pp1647ndash1663 2012
[14] Y Liu ldquoLower bounds for the blow-up time in a non-local reac-tion diffusion problem under nonlinear boundary conditionsrdquoMathematical and ComputerModelling vol 57 no 3-4 pp 926ndash931 2013
[15] Y Liu S G Luo and Y H Ye ldquoBlow-up phenomena for aparabolic problemwith a gradient nonlinearity under nonlinearboundary conditionsrdquo Computers ampMathematics with Applica-tions vol 65 no 8 pp 1194ndash1199 2013
[16] F S Li and J L Li ldquoGlobal existence and blow-up phenom-ena for nonlinear divergence form parabolic equations withinhomogeneous Neumann boundary conditionsrdquo Journal ofMathematical Analysis and Applications vol 385 no 2 pp1005ndash1014 2012
[17] F Liang ldquoBlow-up and global solutions for nonlinear reaction-diffusion equations with nonlinear boundary conditionrdquoApplied Mathematics and Computation vol 218 no 8 pp3993ndash3999 2011
[18] L E Payne G A Philippin and S Vernier Piro ldquoBlow-up phenomena for a semilinear heat equation with nonlinearboundary condition IIrdquoNonlinear Analysis Theory Methods ampApplications vol 73 no 4 pp 971ndash978 2010
[19] J Ding X Gao and S Li ldquoGlobal existence and blow-up prob-lems for reaction diffusion model with multiple nonlinearitiesrdquoJournal of Mathematical Analysis and Applications vol 343 no1 pp 159ndash169 2008
[20] Y W Qi M X Wang and Z J Wang ldquoExistence and non-existence of global solutions of diffusion systems with nonlin-ear boundary conditionsrdquo Proceedings of the Royal Society ofEdinburghmdashSection A Mathematics vol 134 no 6 pp 1199ndash1217 2004
[21] H L Zhang ldquoBlow-up solutions and global solutions for non-linear parabolic problemsrdquoNonlinear AnalysisTheory Methodsamp Applications vol 69 no 12 pp 4567ndash4574 2008
[22] L L Zhang N Zhang and L X Li ldquoBlow-up solutions andglobal existence for a kind of quasilinear reaction-diffusionequationsrdquo Zeitschrift fur Analysis und ihre Anwendungen vol33 no 3 pp 247ndash258 2014
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of