Existence of Positive Solutions for A Fourth-order Boundary Value Problems with p-Laplacian Operators

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.

Existence of Positive Solutions to a Fractional-Kirchhoff System

LetΩbe a bounded smooth domain in RN(N≥3).Assuming that 0<s<1,1<p,q≤N+2s/N-2s with(p,q)≠(N+2s/N-2s,N+2s/N-2s),and a,b>0 are constants,we consider the existence results for positive solutions of a class of fractional elliptic system below,{(a+b[u]^(2)_(s))(-Δ)^(s)u=vp+h_(1)(x,u,v,▽u,▽v),x∈Ω,(-Δ)^(s)v=u^(q)+h_(2)(x,u,▽,▽u,▽v),x∈Q,u,v>0,x∈Ω,u=v=0,x∈RN\Ω.Under some assumptions of hi(x,u,v,▽u,▽v)(i=1,2),we get a priori bounds of the positive solutions to the problem(1.1)by the blow-up methods and rescaling argument.Based on these estimates and degree theory,we establish the existence of positive solutions to problem(1.1).

Positive solutions for a Lotka-Volterra prey-predator model with cross-diffusion and Holling type-Ⅱ functional response

We consider a Lotka-Volterra prey-predator model with cross-diffusion and Holling type-II functional response.The main concern is the existence of positive solutions under the combined effect of cross-diffusion and Holling type-II functional response.Here,a positive solution corresponds to a coexistence state of the model.Firstly,we study the sufficient conditions to ensure the existence of positive solutions by using degree theory and analyze the coexistence region in parameter plane.In addition,we present the uniqueness of positive solutions in one dimension case.Secondly,we study the stability of the trivial and semi-trivial solutions by analyzing the principal eigenvalue of the corresponding linearized system,and then we characterize the stable/unstable regions of semi-trivial solutions in parameter plane.

EXISTENCE OF POSITIVE SOLUTIONS TO SUBLINEAR SECOND-ORDER PERIODIC BOUNDARY VALUE PROBLEM

In this paper, we consider a second-order periodic boundary value problem. By the topological degree theory and fixed point index theory, we prove the existence of positive solutions which gives the relationship between the first positive eigenvalue of the associated eigenvalue problem and the behavior of the nonlinear term of the system.

POSITIVE SOLUTIONS OF HIGHER DIMENSIONAL DISCRETE BOUNDARY VALUE PROBLEM

By means of the critical point theory, we prove the existence of positive solutions for a higher dimensional discrete boundary value problem. Our results generalize one of Agarwal in [2].

EXISTENCE OF POSITIVE SOLUTIONS TO BOUNDARY VALUE PROBLEM OF NONLINEAR FRACTIONAL DIFFERENTIAL EQUATION

In this paper, using the property of the corresponding Green’s function and fixed point index theory, some sufficient conditions for the multiplicity and nonexistence of positive solutions to a class of nonlinear fractional boundary value problem are obtained. Three examples are given to show the effectiveness of our results.

THREE POSITIVE SOLUTIONS TO BVP FOR p-LAPLACIAN IMPULSIVE FUNCTIONAL DYNAMIC EQUATIONS ON A TIME SCALE

In this paper, we axe interested in the existence of three positive solutions to a BVP for p-Laplacian impulsive functional dynamic equations on a time scale. Using the five-functional fixed theory, we establish a Banach space and an appropriate operator. In this paper, we combine the delta-nabla p-Laplacian BVP with impulsive functional dynamic equations, and obtain some new sufficient conditions for the existence of three positive solutions to the BVP, and our result here generalizes the previous related results.

ON THE EXISTENCE OF POSITIVE SOLUTIONS FOR SINGULAR NEUMANN BOUNDARY VALUE PROBLEMS

By using fixed point index theory, we consider the existence of positive solutions for singular nonlinear Neumann boundary value problems. Our main results extend and improve many known results even for non-singular cases.

POSITIVE SOLUTIONS TO A CLASS OF SECOND-ORDER SINGULAR SEMIPOSITIVE NEUMANN BOUNDARY VALUE PROBLEM WITH GENERAL FORM

By constructing an explicit Green function and using the fixed point index theory on a cone, we present some existence results of positive solutions to a class of second-order singular semipositive Neumann boundary value problem, where the nonlinear term is allowed to be nonnegative and unbounded.

EXISTENCE OF POSITIVE SOLUTIONS TO SINGULAR SUBLINEAR SEMIPOSITONE NEUMANN BOUNDARY VALUE PROBLEM

The existence of positive solutions to a singular sublinear semipositone Neumann boundary value problem is considered. In this paper,the nonlinearity term is not necessary to be bounded from below and the function q(t) is allowed to be singular at t = 0 and t = 1.

Multiple positive periodic solutions for a generalized delayed population model with an exploited term

In this paper, the existence of two positive periodic solutions for a generalized delayed population model with an exploited term is established by using the continuation theorem of the coincidence degree theory.

一种新型3-RRPU并联机构的运动学及鲁棒控制研究

针对现有的三平移并联机构大多正解不唯一、较难实现精确稳定运动控制的问题,提出了一种新的3-RRPU型三平移并联机构,同时研究了机构的运动学、动力学及轨迹跟踪控制方法。首先,运用螺旋理论分析了该机构三平移的原理,进行了驱动输入的选取与论证,对机构平台奇异性、驱动奇异性和支链奇异性进行了分析;其次,运用运动学理论建立了运动学模型,推导了位置正、逆解析解;再次,运用拉格朗日动力学理论建立了机构操作空间的刚体动力学模型;最后,提出了一种基于非线性反馈解耦的自适应滑模轨迹跟踪控制方法,以证明其控制稳定性,并基于动力学模型对空间轨迹跟踪精度和控制力矩进行了仿真分析。研究结果表明:3-RRPU并联机构的位置正解在一般位形下具有唯一性,机构的平台奇异位形和驱动奇异位形少且无支链奇异。该轨迹控制方法可使机构在载荷20 kg、速度0.18 m/s、加速度0.12 m/s 2下,实现0.002 m以内的高精度复杂轨迹跟踪;基于Sigmoid函数的轨迹控制方法还能有效削弱控制力矩的抖振,为实现工业领域高速、高精度、高性能的三平移运动提供了新方法。

关于丢番图方程(1023n)^(x)+(64n)^(y)=(1025n)^(z)

设a,b,c是两两互素的正整数且满足商高数条件,即当a,b,c为本原商高数时,方程(an)^(x)+(bn)^(y)=(cn)^(z)仅有正整数解(x,y,z)=(2,2,2).而现有的丢番图方程形式并没有将b的具体形式与初等数论紧密结合,利用奇偶分析法、简单同余理论、将b取为26并与初等数论相结合,还运用了分类讨论、反证法的思想,具体为先采用反证法进行假设,根据所化简的等式选取合适的模数进行推算得出与假设相悖的结论,即证明了:若n为正整数,当(a,b,c)=(1023,64,1025)时,丢番图方程(1023n)x+(64n)y=(1025n)z仅有正整数解(x,y,z)=(2,2,2),以此验证Jesmanowicz猜想成立,这个证明结果使Jesmanowicz猜想更加充实.

基于比率的两种群捕食者-食饵系统的周期解

对于捕食者 食饵系统已有大量的研究工作,主要集中于解的稳定性、持久性等,关于周期性结论很少。本文研究了一类非自治的具有时滞和基于比率且有Machaelis Menten型功能性反应的两种群捕食者 食饵周期系统 x1=x1(t)(a(t)-b(t)x1(t)-c(t)x1(t)x2(t)m(t)x22(t)+x21(t)), x2=x2(t)(-d(t)+e(t)x21(t-τ)m(t)x22(t-τ)+x21(t-τ)),利用Mawhin的重合度理论和不等式技巧,找到了系统的1个先验界,并建立了这类系统正周期解的存在性判据。

带交叉扩散项的捕食模型非常数正解的存在性

讨论了一类具有交叉扩散项的捕食食饵模型正解的存在性。利用最大值原理和Harnack不等式给出了模型正解的先验估计,运用积分性质证明了非常数正解的不存在性,再利用度理论得到了非常数正解存在的充分条件。

一种空间非对称2自由度并联机构设计与应用研究

以一种空间非对称2自由度并联机构为研究对象,通过机构方位特征集理论进行了自由度计算,运用矢量代数法进行正向运动学分析,由雅克比矩阵得到了机构全部奇异位置。基于空间模型理论,综合考虑机构几何尺寸及不同类型输入量取值范围等参数,将上述参数无量纲化处理后作为坐标系,建立了此机构的空间模型。在模型中绘制了此机构奇异曲面,直观分析机构参数与机构奇异性之间的关系,并依据奇异曲面在空间模型中的分布状况,进行机构参数优化,实现减少机构奇异的目的,最后进行了机构工程应用举例。

带非线性边界条件的一阶微分方程多个正解的存在性

研究带非线性边界条件的一阶微分方程边值问题{u'(t)-a(t)u(t)+λb(t)f(u(t))=0,t∈[0,1],u(1)-u(0)=λg(u(1))正解的存在性及多解性,其中λ>0为参数,a,b∈C([0,+∞),(0,+∞)),f∈C([0,+∞),(0,+∞))且f_∞=(f(u))/u=∞,g∈C([0,∞),(0,+∞))且非增,主要结果的证明基于上下解方法和拓扑度理论.

被捕食者带有第三边值的捕食模型的正稳态解的存在性

该文研究了一类被捕食者带有第三边值的捕食模型．首先获得了它存在正稳态解的充要条件是a>mb+d1λ1;然后研究了它的正稳态解的局部稳定性和唯一性;最后讨论了充分大的扩散参数对它的正稳态解的存在性的影响．

周期捕食被捕食系统正周期解存在的充要条件

研究周期环境下的Lotka-Volterra捕食被捕食系统。采用分歧理论和微分不等式方法,建立了关于正周期解存在的一个充分必要判别准则,总结和推广了文[1—4]中的主要结果。

一类三种群离散型捕食系统的周期解

本文研究了一类三种群离散型捕食者 食饵系统 .利用重合度理论建立了这类系统正周期解的存在性判据 .