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Existence of Positive Solutions for a Class of Degenerate and Nondegenerate Stable Diffusion Models
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作者 张彦肖 《Chinese Quarterly Journal of Mathematics》 CSCD 2000年第3期50-56,共7页
This paper is concerned with a class of degenerate and nondegenerate stable diffusion models.By using the upper and lower solution method and Schauder fixed point principle,the author studies the existence of positive... This paper is concerned with a class of degenerate and nondegenerate stable diffusion models.By using the upper and lower solution method and Schauder fixed point principle,the author studies the existence of positive solutions for these stable_diffusion models under some conditions. 展开更多
关键词 weak upper and lower solutions elliptic system positive solution
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The Estimation for Lower Bounds of the Solutions of Fermat's Equation
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作者 乐茂华 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第2期52-55,共4页
Let p be a prime with p≡3(mod 4). In this paper,by using some results relate the representation of integers by primitive binary quadratic forms,we prove that if x,y,z are positive integers satisfying x^p+y^p=z^p, p|x... Let p be a prime with p≡3(mod 4). In this paper,by using some results relate the representation of integers by primitive binary quadratic forms,we prove that if x,y,z are positive integers satisfying x^p+y^p=z^p, p|xyz, x<y<z, then y>p^(6p-2)/2. 展开更多
关键词 Fermat's last theorem integer solution lower bound
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SOME NECESSARY AND SUFFICIENT CONDITIONS FOR EXISTENCE OF POSITIVE SOLUTIONS FOR THIRD ORDER SINGULAR SUBLINEAR MULTI-POINT BOUNDARY VALUE PROBLEMS 被引量:5
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作者 韦忠礼 《Acta Mathematica Scientia》 SCIE CSCD 2014年第6期1795-1810,共16页
We mainly study the existence of positive solutions for the following third order singular multi-point boundary value problem{x^(3)(t) + f(t, x(t), x′(t)) = 0, 0 〈 t 〈 1,x(0)-∑i=1^m1 αi x(ξi) = 0... We mainly study the existence of positive solutions for the following third order singular multi-point boundary value problem{x^(3)(t) + f(t, x(t), x′(t)) = 0, 0 〈 t 〈 1,x(0)-∑i=1^m1 αi x(ξi) = 0, x′(0)-∑i=1^m2 βi x′(ηi) = 0, x′(1)=0,where 0 ≤ ai≤∑i=1^m1 αi 〈 1, i = 1, 2, ···, m1, 0 〈 ξ1〈 ξ2〈 ··· 〈 ξm1〈 1, 0 ≤βj≤∑i^m2=1βi〈1,J=1,2, ···, m2, 0 〈 η1〈 η2〈 ··· 〈 ηm2〈 1. And we obtain some necessa βi 〈=11, j = 1,ry and sufficient conditions for the existence of C^1[0, 1] and C^2[0, 1] positive solutions by constructing lower and upper solutions and by using the comparison theorem. Our nonlinearity f(t, x, y)may be singular at x, y, t = 0 and/or t = 1. 展开更多
关键词 boundary value problems positive solutions lower and upper solutions comparison theorem
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A Generalized Upper and Lower Solution Method for Singular Discrete Boundary Value Problems 被引量:1
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作者 胡卫敏 韦俊 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2007年第2期212-219,共8页
This paper presents new existence results for singular discrete boundary value problems. In particular our nonlinearity may be singular in its dependent variable and is allowed to change sign.
关键词 upper and lower solutions discrete boundary value problem EXISTENCE SINGULAR
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Existence of Solutions for S-L Singular Boundary Value Problems with p-Laplacian Operators
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作者 郭彦平 葛渭高 单文锐 《Journal of Beijing Institute of Technology》 EI CAS 2002年第2期220-224,共5页
The existence of solutions for singular nonlinear two point boundary value problems subject to Sturm Liouville boundary conditions with p Laplacian operators is studied by the method of upper and lower solution... The existence of solutions for singular nonlinear two point boundary value problems subject to Sturm Liouville boundary conditions with p Laplacian operators is studied by the method of upper and lower solutions. The proof is based on an application of Schauder’s fixed point theorem to a modified problem whose solutions are that of the original one. At the same time, Arzela Ascoli theorem is used to prove that the defined operator N is a compact map. 展开更多
关键词 nonlinear boundary value problems p Laplacian operators fixed point upper solution lower solution
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POSITIVE SOLUTIONS FOR SINGULAR BVPs ON THE POSITIVE HALF-LINE ARISING FROM EPIDEMIOLOGY AND COMBUSTION THEORY 被引量:2
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作者 Smaïl Djebali Ouiza Saïfi 闫宝强 《Acta Mathematica Scientia》 SCIE CSCD 2012年第2期672-694,共23页
In this work, we are concerned with the existence and multiplicity of positive solutions for singular boundary value problems on the half-line. Two problems from epi- demiology and combustion theory set on the positiv... In this work, we are concerned with the existence and multiplicity of positive solutions for singular boundary value problems on the half-line. Two problems from epi- demiology and combustion theory set on the positive half-line are investigated upper and lower solution techniques combined with fixed point index on cones in priate Banach spaces. The results complement recent ones in the literature. We use appropriate Banach spaces. The results complement recent ones in the literature. 展开更多
关键词 Fixed points index positive solution singular problem CONE lower andupper solution HALF-LINE
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ASYMPTOTIC BEHAVIOR OF SOLUTIONS TO THE HEAT EQUATIONS WITH NONLINEAR BOUNDARY CONDITIONS 被引量:1
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作者 汤燕斌 周笠 Omer Ali 《Acta Mathematica Scientia》 SCIE CSCD 2004年第2期307-312,共6页
The purpose of this paper is to investigate the stability and asymptotic behavior of the time-dependent solutions to a linear parabolic equation with nonlinear boundary condition in relation to their corresponding ste... The purpose of this paper is to investigate the stability and asymptotic behavior of the time-dependent solutions to a linear parabolic equation with nonlinear boundary condition in relation to their corresponding steady state solutions. Then, the above results are extended to a semilinear parabolic equation with nonlinear boundary condition by analyzing the corresponding eigenvalue problem and using the method of upper and lower solutions. 展开更多
关键词 Asymptotic behavior heat equation nonlinear boundary condition upper and lower solutions
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Existence of Multiple Positive Solutions of Discrete Boundary Value Problem
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作者 周桂云 《Chinese Quarterly Journal of Mathematics》 CSCD 2002年第4期99-104,共6页
In this paper, we consider the existence of multiple positive solutions of discrete boundary value problem. The theory of fixed point index is used here to derive the existence theorem.
关键词 nonlinear difference equation upper and lower solutions the fixed point index
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Existence of Positive Solutions for A Fourth-order Boundary Value Problems with p-Laplacian Operators
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作者 WANG Wan-peng 《Chinese Quarterly Journal of Mathematics》 2018年第4期377-385,共9页
This paper investigates the existence of positive solutions for a fourth-order p-Laplacian nonlinear equation. We show that, under suitable conditions, there exists a positive number λ~*such that the above problem ha... This paper investigates the existence of positive solutions for a fourth-order p-Laplacian nonlinear equation. We show that, under suitable conditions, there exists a positive number λ~*such that the above problem has at least two positive solutions for 0 < λ < λ~* , at least one positive solution for λ = λ~* and no solution forλ > λ~* by using the upper and lower solutions method and fixed point theory. 展开更多
关键词 FOURTH-ORDER P-LAPLACIAN POSITIVE solutions upper and lower solutions method Fixed point theory
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Existence of Solutions to the Higher Order Nonlinear Differential Equations
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作者 TANG Lin-shan JIANG Cheng-shun 《Chinese Quarterly Journal of Mathematics》 CSCD 2012年第1期1-10,共10页
This paper is concerned with the following n-th ordinary differential equation:{u~(n)(t)=f(t,u(t),u~(1)(t),···,u~(n-1) (t)),for t∈(0,1),u~(i) (0)=0,0 ≤i≤n3,au~(n-2)(0)du~(n-1)(0)=0,cu~(n-2)(1)... This paper is concerned with the following n-th ordinary differential equation:{u~(n)(t)=f(t,u(t),u~(1)(t),···,u~(n-1) (t)),for t∈(0,1),u~(i) (0)=0,0 ≤i≤n3,au~(n-2)(0)du~(n-1)(0)=0,cu~(n-2)(1)+du~(n-1)(1)=0,where a,c ∈ R,,≥,such that a~2 + b~2 >0 and c~2+d~2>0,n ≥ 2,f:[0,1] × R → R is a continuous function.Assume that f satisfies one-sided Nagumo condition,the existence theorems of solutions of the boundary value problem for the n-th-order nonlinear differential equations above are established by using Leray-Schauder degree theory,lower and upper solutions,a priori estimate technique. 展开更多
关键词 n-th order boundary value problems one-sided Nagumo condition lower and upper solutions a priori estimates Leray-Schauder degree
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The Existence of Positive Solutions for Volterra-Lotka Cooperating Model with Diffusion
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作者 WANG Li-zhou MEI Li-quan 《Chinese Quarterly Journal of Mathematics》 CSCD 2010年第4期522-529,共8页
In this paper,using the existence and comparison result for the quasi-monotone increasing system developed by C V Pao,the upper and lower solutions principle and an iterative method,we investigate the existence of the... In this paper,using the existence and comparison result for the quasi-monotone increasing system developed by C V Pao,the upper and lower solutions principle and an iterative method,we investigate the existence of the positive solutions of the Volterra-Lotka cooperating model. 展开更多
关键词 positive solution Volterra-Lotka model upper and lower solutions
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GLOBAL EXISTENCE OF SOLUTIONS FOR A STRONGLY COUPLED REACTION-DIFFUSION SYSTEM
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作者 江成顺 李海峰 《Acta Mathematica Scientia》 SCIE CSCD 1998年第1期1-10,共10页
This paper is concerned with an Initial Boundary Value Problem (IBVP) for a strongly coupled semilinear reaction-diffusion system. By using the upper and lower solutions method and Leray-Schauder fixed point theorem a... This paper is concerned with an Initial Boundary Value Problem (IBVP) for a strongly coupled semilinear reaction-diffusion system. By using the upper and lower solutions method and Leray-Schauder fixed point theorem and so on, the authors prove the global existence and uniqueness of a. smooth. solution for this IBVP under some appropriate conditions. 展开更多
关键词 strongly coupled reaction-diffusion system global smooth solution upper and lower solutions Leray-Schauder fixed point theorem
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NEW EXISTENCE RESULTS OF POSITIVE SOLUTION FOR A CLASS OF NONLINEAR FRACTIONAL DIFFERENTIAL EQUATIONS 被引量:4
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作者 李楠 王长有 《Acta Mathematica Scientia》 SCIE CSCD 2013年第3期847-854,共8页
In this article, the existence and uniqueness of positive solution for a class of nonlinear fractional differential equations is proved by constructing the upper and lower control functions of the nonlinear term witho... In this article, the existence and uniqueness of positive solution for a class of nonlinear fractional differential equations is proved by constructing the upper and lower control functions of the nonlinear term without any monotone requirement. Our main method to the problem is the method of upper and lower solutions and Schauder fixed point theorem. Finally, we give an example to illuminate our results. 展开更多
关键词 Fractional differential equations positive solution upper and lower solutions existence and uniqueness fixed point theorem
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THE EXISTENCE OF POSITIVE SOLUTION FOR THE NONLINEARSINGULAR BOUNDARY VALUE PROBLEMS
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作者 刘文斌 《Journal of China University of Mining and Technology》 1994年第2期122-128,共7页
Making use of upper and lower solutions and analytical method, the author studies theexistence of positive solution for the singular equation x + f(t, z) = 0 satisfying nonlinear boundary conditions: x (0) = 0, h(x (1... Making use of upper and lower solutions and analytical method, the author studies theexistence of positive solution for the singular equation x + f(t, z) = 0 satisfying nonlinear boundary conditions: x (0) = 0, h(x (1), x’ (1)) = 0, g (z (0), x’(0)) = 0, and x (1) = 0,which extends the result of J. V. Baxley. 展开更多
关键词 singular boundary value problem nonlinear boundary condition upper and lower solutions
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基于下限模型的临界滑动面理论与数值解法
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作者 郑颖人 张金良 +4 位作者 尹德文 邵颖 苏凯 吴昊 张智沛 《岩土工程学报》 北大核心 2025年第2期438-442,共5页
临界滑动面对岩土工程的加固处理有着重要意义。目前对于临界滑动面的研究多采用上限法,基于下限定理或下限模型的临界滑动面理论与数值解法目前尚未见到。在下限模型的基础上,提出了基于下限模型的临界滑动面理论,给出了相应的数值解法... 临界滑动面对岩土工程的加固处理有着重要意义。目前对于临界滑动面的研究多采用上限法,基于下限定理或下限模型的临界滑动面理论与数值解法目前尚未见到。在下限模型的基础上,提出了基于下限模型的临界滑动面理论,给出了相应的数值解法;并以黏性土体直立边坡的临界高度问题为例,验证了临界滑动面理论与数值解法的适用性。 展开更多
关键词 下限模型 临界滑动面 数值解法
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Reversible phase transition poly(benzyl methacrylate)/ionic liquid electrolytes for effective overheating protection in lithium batteries
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作者 Qian Yu Wei Sun +10 位作者 Jialing Zhu Haoxiang Li Shuai Wang Longqing Huang Qian Qiu Haoran Tian He Miao Fu Wang Chunfei Zhang Jinliang Yuan Lan Xia 《Journal of Energy Chemistry》 2025年第2期76-86,I0003,共12页
Battery safety is influenced by various factors,with thermal runaway being one of the most significant concerns.While most studies have concentrated on developing one-time,self-activating mechanism for thermal protect... Battery safety is influenced by various factors,with thermal runaway being one of the most significant concerns.While most studies have concentrated on developing one-time,self-activating mechanism for thermal protection,such as temperature-responsive electrodes,and thermal-shutdown separators,these methods only provide irreversible protection.Recently,reversible temperature-sensitive electrolytes have emerged as promising alternatives,offering both thermo-reversibility and self-protective properties.However,further research is crucial to fully understand these thermal-shutdown electrolytes.In this study,we propose lower critical solution temperature(LCST)phase behavior poly(benzyl methacrylate)/imidazolium-based ionic liquid mixtures to prepare temperature-sensitive electrolytes that provide reversible thermal shutdown protection of batteries.This electrolyte features an appropriate protection temperature(~105℃)and responds quickly within a 1 min at 105℃,causing cells to hardly discharge as the voltage suddenly drops to 3.38 V,and providing efficient thermal shutdown protection within 30 min.Upon cooling back to room temperature,the battery regains its original performance.Additionally,the electrolyte exhibits excellent cycling stability with the capacity retention of the battery is 91.6%after 500 cycles.This work provides a viable solution for preventing batteries from thermal runaway triggered by overheating. 展开更多
关键词 Lithium-ion battery Safety OVERHEATING Thermal runaway lonic liquid lower critical solution temperature
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抽水蓄能电站库盆防渗方案比选方法研究
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作者 徐汇 曾理 王杨 《中国水能及电气化》 2025年第1期3-7,15,共6页
文章以宁波北仑梅山港抽水蓄能电站工程为研究对象,采用层次分析法构建了抽水蓄能电站库盆防渗方案比选方法,并对该工程展开了分析计算工作。结合层次分析法计算要点和抽水蓄能电站防渗工作关键技术构建了5决策+16指标的评价指标体系;... 文章以宁波北仑梅山港抽水蓄能电站工程为研究对象,采用层次分析法构建了抽水蓄能电站库盆防渗方案比选方法,并对该工程展开了分析计算工作。结合层次分析法计算要点和抽水蓄能电站防渗工作关键技术构建了5决策+16指标的评价指标体系;通过计算,其结果与传统防渗方案比选结果一致。该研究内容可为后续工作的开展提供理论支撑。 展开更多
关键词 抽水蓄能电站 上水库 库盆防渗工程 防渗方案比选 层次分析法
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Existence of Travelling Wave Fronts to a Delayed Lattice Model for Population 被引量:1
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作者 孙风兰 汤燕斌 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2008年第1期96-102,共7页
This paper considers the travelling wave fronts to a delayed lattice differential equation. The existence of the travelling wave solutions is proved by making use of the technique of the upper and lower solutions deve... This paper considers the travelling wave fronts to a delayed lattice differential equation. The existence of the travelling wave solutions is proved by making use of the technique of the upper and lower solutions developed by J Wu and X Zou in [6]. This work extends that of [4] in a general class of nonlinear terms. 展开更多
关键词 travelling wave front lattice differential equation delay upper and lower solutions
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Asympototic Behavior of Semilinear Periodic-Parbolic Boundary Value Problem
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作者 冯秀芳 杨万利 《Chinese Quarterly Journal of Mathematics》 CSCD 1997年第1期18-24, ,共7页
We study a class of semilinear periodic-parabolic boundary value problem with small diffusion coefficients,give its asymptotic behavior when the diffusion cofficients go to limit zero.
关键词 periodic solution upper lower solution
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Traveling Waves for an Epidemic Model with Vaccination and Nonlocal Diffusion
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作者 WANG Zhi-ping XU Rui ZHANG Shi-hua 《Chinese Quarterly Journal of Mathematics》 2015年第2期287-299,共13页
An epidemic model with vaccination and nonlocal diffusion is proposed, and the existence of traveling wave solutions of this model is studied. By the cross-iteration scheme companied with a pair of upper and lower sol... An epidemic model with vaccination and nonlocal diffusion is proposed, and the existence of traveling wave solutions of this model is studied. By the cross-iteration scheme companied with a pair of upper and lower solutions and Schauder's fixed point theorem,sufficient conditions are obtained for the existence of a traveling wave solution connecting the disease-free steady state and the endemic steady state. 展开更多
关键词 VACCINATION traveling wave solution nonlocal diffusion upper-lower solutions
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