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Existence of Positive Solutions to Second Order Neumann Boundary Value Problems 被引量:31
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作者 蒋达清 刘辉昭 《Journal of Mathematical Research and Exposition》 CSCD 2000年第3期360-364,共5页
The existence of positive solutions to second-order Neumann BVPs -u' + Mu = f(t, u), u'(0) = u'(1) = 0 and u' + Mu = f(t, u), u'(0) =u'(1) is proved by a simple application of a Fixed Poin... The existence of positive solutions to second-order Neumann BVPs -u' + Mu = f(t, u), u'(0) = u'(1) = 0 and u' + Mu = f(t, u), u'(0) =u'(1) is proved by a simple application of a Fixed Point Theorem in cones due to Krasnoselskii[1,6]. 展开更多
关键词 Neumann bvp positive solutions the fixed point theorem.
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ON THE EXISTENCE OF POSITIVE SOLUTIONS TO SECOND ORDER PERIODIC BVPS 被引量:28
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作者 蒋达清 《Acta Mathematica Scientia》 SCIE CSCD 1998年第S1期31-35,共5页
The existence of positive solutions to second-order periodic BVPs-u'+Mu =j(t, u),t(0) = u(2π),u'(0) = '(2π) and u'+ Mu = I(t, u), u(0) = u(2π), u'(0) = u'(2π)is proved by a simple appliCati... The existence of positive solutions to second-order periodic BVPs-u'+Mu =j(t, u),t(0) = u(2π),u'(0) = '(2π) and u'+ Mu = I(t, u), u(0) = u(2π), u'(0) = u'(2π)is proved by a simple appliCation of a Fixed point Theorem in cones due to Krasnoselskii. 展开更多
关键词 Periodic bvp. positive solutions. the fixed point theorem
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GPS在物理大地测量中的应用及GPS边值问题 被引量:15
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作者 李斐 陈武 岳建利 《测绘学报》 EI CSCD 北大核心 2003年第3期198-203,共6页
针对GPS技术逐步用于物理大地测量的现状,从物理大地测量的基本原理及方法入手,分析了GPS对传统物理大地测量理论及方法所产生的影响、GPS在解决物理大地测量中的一些难题所发挥的作用以及对物理大地测量的一些功能所造成的变化。重点... 针对GPS技术逐步用于物理大地测量的现状,从物理大地测量的基本原理及方法入手,分析了GPS对传统物理大地测量理论及方法所产生的影响、GPS在解决物理大地测量中的一些难题所发挥的作用以及对物理大地测量的一些功能所造成的变化。重点讨论了物理大地测量边值问题的基本属性的改变、第二边值问题的应用、高程系统的确定、GPS边值问题的定义、特征及求解。最后,对GPS与物理大地测量进一步结合所面临的有关问题进行了简要论述。 展开更多
关键词 GPS 物理大地测量 边值问题 扰动重力 高程系统
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竹酢粉对育肥猪肉品质和风味的影响 被引量:11
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作者 董丽 仲召鑫 +4 位作者 王淑楠 彭众 刘子娟 唐慧娟 喻礼怀 《动物营养学报》 CAS CSCD 北大核心 2017年第3期916-922,共7页
本试验旨在研究竹酢粉对育肥猪肉品质和风味的影响。试验选择40头体重相近育肥猪,随机分成5组(每组4个重复,每个重复2头)。对照组(CON)饲喂基础饲粮,抗生素组(ANT)饲喂基础饲粮+0.12%复合抗生素,竹酢粉组分别饲喂基础饲粮+0.5%(BV5)、1.... 本试验旨在研究竹酢粉对育肥猪肉品质和风味的影响。试验选择40头体重相近育肥猪,随机分成5组(每组4个重复,每个重复2头)。对照组(CON)饲喂基础饲粮,抗生素组(ANT)饲喂基础饲粮+0.12%复合抗生素,竹酢粉组分别饲喂基础饲粮+0.5%(BV5)、1.0%(BV10)和1.5%(BV15)的竹酢粉,试验期60 d。结果表明:1)BV5和BV10猪肉红度值显著高于CON和ANT(P<0.05),BV10和BV15猪肉剪切力显著低于CON(P<0.05),各竹酢粉组猪肉剪切力均显著低于ANT(P<0.05);2)BV10和BV15猪肉中天冬氨酸和风味氨基酸含量显著高于CON和ANT(P<0.05),各竹酢粉组猪肉中谷氨酸含量均显著高于CON和ANT(P<0.05);3)BV5和BV10猪肉中肌苷酸含量显著高于CON和ANT(P<0.05),BV15猪肉中肌苷酸含量显著高于ANT(P<0.05);4)BV10猪肉中棕榈酸和BV5猪肉中棕榈油酸含量显著高于其他各组(P<0.05),BV10和BV15猪肉中十八烷烯酸含量显著高于CON(P<0.05)。综上,竹酢粉可改善育肥猪肉品质,提高猪肉风味和营养价值,效果优于抗生素,建议添加量为1.0%。 展开更多
关键词 竹酢粉 抗生素 肉品质 风味氨基酸 脂肪酸
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天然气水合物抑制剂BVP性能研究 被引量:6
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作者 全红平 李强 +2 位作者 鲁红升 黄志宇 蔡馨 《科学技术与工程》 北大核心 2013年第6期1442-1445,1452,共5页
随着国内天然气开采规模的日益扩大和深海开采的进行,由天然气水合物所引起的问题,日益受到了石油天然气研究人员的重视。为抑制天然气水合物的生成,急需研究开发出加量少、效率高的水合物抑制剂。为此,自主合成了新型动力学水合物抑制... 随着国内天然气开采规模的日益扩大和深海开采的进行,由天然气水合物所引起的问题,日益受到了石油天然气研究人员的重视。为抑制天然气水合物的生成,急需研究开发出加量少、效率高的水合物抑制剂。为此,自主合成了新型动力学水合物抑制剂BVP。采用自制评价设备,以四氢呋喃法[THF]对其性能进行了评价。评价结果:BVP加量为0.5%~0.75%时,水合物结冰温度为-8℃,过冷度为-10℃。结合天然气水合物抑制剂PVP做性能对比,BVP的性能明显优于PVP;BVP浊点较PVP浊点提高了27.2℃,相同加量条件下BVP承受过冷度较PVP承受过冷度低2~3℃。结合热力学抑制剂复配,最优复配方案:5%~10%NaCl+0.5%BVP,该复配方案下溶液能够承受过冷度达-12℃~-16℃。 展开更多
关键词 天然气水合物 动力学抑制剂 过冷度THF bvp PVP
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Galerkin-Bernstein Approximations for the System of Third-Order Nonlinear Boundary Value Problems
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作者 Snigdha Dhar Md. Shafiqul Islam 《Journal of Applied Mathematics and Physics》 2024年第6期2083-2101,共19页
This paper is devoted to find the numerical solutions of one dimensional general nonlinear system of third-order boundary value problems (BVPs) for the pair of functions using Galerkin weighted residual method. We der... This paper is devoted to find the numerical solutions of one dimensional general nonlinear system of third-order boundary value problems (BVPs) for the pair of functions using Galerkin weighted residual method. We derive mathematical formulations in matrix form, in detail, by exploiting Bernstein polynomials as basis functions. A reasonable accuracy is found when the proposed method is used on few examples. At the end of the study, a comparison is made between the approximate and exact solutions, and also with the solutions of the existing methods. Our results converge monotonically to the exact solutions. In addition, we show that the derived formulations may be applicable by reducing higher order complicated BVP into a lower order system of BVPs, and the performance of the numerical solutions is satisfactory. . 展开更多
关键词 System of Third-Order bvp Galerkin Method Bernstein Polynomials Nonlinear bvp Higher-Order bvp
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Existence of Positive Solutions for a Third-Order Three-Point Boundary Value Problem with Semipositone Nonlinearity * 被引量:5
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作者 姚庆六 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2003年第4期591-596,共6页
The existence of positive solutions is investigated for following semipositone nonlinear third-order three-point BVP ω''(t) - λf(t,w(t)) = 0, 0 ≤ t ≤ 1, ω(0) = ω'(n) = ω'(1) = 0.
关键词 third-order semipositone ODE three-point bvp existence ot positive solution fixed point theorem on cone.
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驾驶人公路驾车过程中主要生理参数变化规律研究 被引量:7
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作者 胡立伟 林玉珍 《交通运输系统工程与信息》 EI CSCD 北大核心 2014年第1期41-46,共6页
为了探究驾驶人在不同等级公路上驾车过程中生理心理指标变化情况,本文利用Nexus-10多通道生物生理记录仪,对驾驶人在4类等级公路上进行了实车动态测试实验.通过对实验采集的生理特性指标(脑电图、心率、血容量、呼吸等)数据深入分析,... 为了探究驾驶人在不同等级公路上驾车过程中生理心理指标变化情况,本文利用Nexus-10多通道生物生理记录仪,对驾驶人在4类等级公路上进行了实车动态测试实验.通过对实验采集的生理特性指标(脑电图、心率、血容量、呼吸等)数据深入分析,得到不同类驾驶人在不同等级公路上驾车过程中的主要生理特性指标动态变化规律,并对规律的差异性及其中的峰值产生原因进行了深入分析.本文实验过程与方法及其分析结论可为公路线形设计、交通设施设计设置、交通环境治理等提供实验依据,为公路交通管理与控制等提供实验与理论参考. 展开更多
关键词 公路运输 生理指标 驾驶人 脑电图 心率 血容量 呼吸
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Several Existence Theorems for Positive Radial Solutions to a Semilinear Elliptic BVP 被引量:3
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作者 姚庆六 《Northeastern Mathematical Journal》 CSCD 2001年第2期169-174,共6页
The existence of positive radial solutions to the second order semilinear elliptic BVPΔu(X)+g(|X|)f(u(X))=0, R 1<|X|<R 2, u(X)=0, |X|=R 1 or |X|=R 2is considered. A general existence criterion and se... The existence of positive radial solutions to the second order semilinear elliptic BVPΔu(X)+g(|X|)f(u(X))=0, R 1<|X|<R 2, u(X)=0, |X|=R 1 or |X|=R 2is considered. A general existence criterion and several existence theorems of positive radial solution are established. Here it is not required that lim l→0f(l)/l and lim l→∞f(l)/l exist. 展开更多
关键词 second order elliptic equation Dirichlet bvp in annulus positive radial solution existence theorem
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Positive Solutions of Fourth Order Singular Boundary Value Problems 被引量:1
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作者 孙彦 徐本龙 《Northeastern Mathematical Journal》 CSCD 2004年第3期355-362,共8页
Using fixed point index theory, we study the existence of positive solutionsof the fourth order differential equation with some general boundary conditions, where g(t) is allowed to be singular at t=0 and/or 1. Our re... Using fixed point index theory, we study the existence of positive solutionsof the fourth order differential equation with some general boundary conditions, where g(t) is allowed to be singular at t=0 and/or 1. Our results significantly extend and improve many known results even for non-singular cases. An example is given to show how to apply our theorems. 展开更多
关键词 positive solution fixed point index bvp
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含参数常微分方程边值问题的改进COLSYS算法 被引量:1
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作者 袁驷 方亚非 《计算力学学报》 CAS CSCD 1999年第2期162-168,共7页
对常微分方程求解器COLSYS的算法进行了分析、研究和改进,使其能够对参数方程和常微分方程的联立体系直接求解,一方面,免除了目前不得不采用的平凡常微分方程技巧所带来的大量不必要的计算,提高了效率;另一方面,由于减小了... 对常微分方程求解器COLSYS的算法进行了分析、研究和改进,使其能够对参数方程和常微分方程的联立体系直接求解,一方面,免除了目前不得不采用的平凡常微分方程技巧所带来的大量不必要的计算,提高了效率;另一方面,由于减小了问题的规模,使条件数降低,从而改进了数值稳定性和精度。 展开更多
关键词 含参数 常微分方程 边值问题 COLSYS 求解器
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关于奇摄动拟线性系统 被引量:4
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作者 刘光旭 《应用数学和力学》 EI 1987年第11期967-976,共10页
本文目的在于对非线性两点边值问题(1.1)证明其解存在的充分条件。并利用这一结果研究拟线性弱耦合奇摄动系统(DP)_q的边界层现象。
关键词 奇摄动系统 边界层 定义 附面层 流体层 bvp 边值问题 数学问题 拟线性 退化解 定理 分量 右导数 左导数
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Positive Solutions to a Singular Third-Order Three-Point Boundary Value Problem 被引量:2
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作者 Hong Ping WU 《Journal of Mathematical Research and Exposition》 CSCD 2011年第2期287-294,共8页
In this paper,we study the existence of positive solutions for the nonlinear singular third-order three-point boundary value problemu (t) = λa(t)f(t,u(t)),u(0) = u (1) = u (η) = 0,where λ is a positiv... In this paper,we study the existence of positive solutions for the nonlinear singular third-order three-point boundary value problemu (t) = λa(t)f(t,u(t)),u(0) = u (1) = u (η) = 0,where λ is a positive parameter and 0 ≤ η 1 2 .By using the classical Krasnosel’skii’s fixed point theorem in cone,we obtain various new results on the existence of positive solution,and the solution is strictly increasing.Finally we give an example. 展开更多
关键词 positive solutions SINGULAR third-order three-point bvp fixed point theorem
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The Fine Spectra of the Difference Operator △ Over the Sequence Space bv_p,(1≤p<∞) 被引量:2
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作者 Ali M.AKHMEDOV Feyzi BASAR 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2007年第10期1757-1768,共12页
The sequence space bvp consisting of all sequences (xk) such that (xk -xk-1) belongs to the space gp has recently been introduced by Basar and Altay [Ukrainian Math. J., 55(1), 136-147(2003)]; where 1 ≤ p ≤ ... The sequence space bvp consisting of all sequences (xk) such that (xk -xk-1) belongs to the space gp has recently been introduced by Basar and Altay [Ukrainian Math. J., 55(1), 136-147(2003)]; where 1 ≤ p ≤ ∞. In the present paper, some results concerning with the continuous dual and f-dual, and the AD-property of the sequence space bvp have been given and the norm of the difference operator A acting on the sequence space bvp has been found. The fine spectrum with respect to the Goldberg's classification of the difference operator △ over the sequence space bvp has been determined, where 1≤p〈∞. 展开更多
关键词 spectrum of an operator difference operator the continuous dual and f-dual of a sequence space the AD-property and the sequence space bvp
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Bursting phenomena as well as the bifurcation mechanism in a coupled BVP oscillator with periodic excitation 被引量:2
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作者 张晓芳 吴磊 毕勤胜 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第7期151-157,共7页
We explore the complicated bursting oscillations as well as the mechanism in a high-dimensional dynamical system.By introducing a periodically changed electrical power source in a coupled BVP oscillator, a fifth-order... We explore the complicated bursting oscillations as well as the mechanism in a high-dimensional dynamical system.By introducing a periodically changed electrical power source in a coupled BVP oscillator, a fifth-order vector field with two scales in frequency domain is established when an order gap exists between the natural frequency and the exciting frequency.Upon the analysis of the generalized autonomous system, bifurcation sets are derived, which divide the parameter space into several regions associated with different types of dynamical behaviors. Two typical cases are focused on as examples,in which different types of bursting oscillations such as sub Hopf/sub Hopf burster, sub Hopf/fold-cycle burster, and doublefold/fold burster can be observed. By employing the transformed phase portraits, the bifurcation mechanism of the bursting oscillations is presented, which reveals that different bifurcations occurring at the transition between the quiescent states(QSs) and the repetitive spiking states(SPs) may result in different forms of bursting oscillations. Furthermore, because of the inertia of the movement, delay may exist between the locations of the bifurcation points on the trajectory and the bifurcation points obtained theoretically. 展开更多
关键词 coupled bvp oscillator two timescales bursting oscillations bifurcation mechanism
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MULTIPLE POSITIVE SOLUTIONS TO A SINGULAR THIRD-ORDER THREE-POINT BOUNDARY VALUE PROBLEM 被引量:2
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作者 Hongping Wu(College of Math. and Information Science,Northwest Normal University,Lanzhou 730070) 《Annals of Differential Equations》 2011年第3期379-383,共5页
In this paper,we study a singular third-order three-point boundary value problem. By a fixed point theorem of cone expansion-compression type due to Krasnosel’skii,we obtain various new results on the existence of tw... In this paper,we study a singular third-order three-point boundary value problem. By a fixed point theorem of cone expansion-compression type due to Krasnosel’skii,we obtain various new results on the existence of two positive solutions to the problem,whose coefficient is allowed to have suitable singularities. Finally,we give an example to verify our results. 展开更多
关键词 third-order three-point bvp positive solutions SINGULAR fixed point theorem
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POSITIVE SOLUTIONS OF FOURTH-ORDER ORDINARY DIFFERENTIAL EQUATIONS 被引量:2
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作者 马如云 张凤然 《Acta Mathematica Scientia》 SCIE CSCD 1998年第S1期124-128,共5页
Under suitable conditions on h(x) and f(u), the authors show that the following boundary value problem has at least one positive solution. Moreover, the authors also establish several existence theorems of multiple po... Under suitable conditions on h(x) and f(u), the authors show that the following boundary value problem has at least one positive solution. Moreover, the authors also establish several existence theorems of multiple positive solutions. 展开更多
关键词 fourth-order bvp positive solution CONE fixed point
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双侧前庭病诊断与治疗研究进展
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作者 陈晓烨 刘波 肖红俊 《中华耳鼻咽喉头颈外科杂志》 CSCD 北大核心 2024年第8期890-896,856,共8页
双侧前庭病(bilateral vestibulopathy,BVP)是指双侧前庭终器、神经或两者功能的严重降低或缺失的一种慢性前庭综合征,是一种基于前庭功能的诊断,而非疾病实体。其临床表现为不稳感,且有跌倒风险,极大降低了患者生活质量。BVP病因复杂... 双侧前庭病(bilateral vestibulopathy,BVP)是指双侧前庭终器、神经或两者功能的严重降低或缺失的一种慢性前庭综合征,是一种基于前庭功能的诊断,而非疾病实体。其临床表现为不稳感,且有跌倒风险,极大降低了患者生活质量。BVP病因复杂、起病隐匿,易被漏诊或误诊。BVP的诊断需综合临床表现和多项前庭检查结果,然而Barany协会近年发布的共识仅能明确部分极重度患者的诊断。本文综述了BVP的临床新进展,包括症状、病因、分型、前庭功能检查和治疗策略等。 展开更多
关键词 前庭功能 bvp 治疗策略
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SOLVABILITY OF M-POINT BOUNDARY VALUE PROBLEMS FOR SECOND ORDER ORDINARY DIFFERENTIAL EQUATIONS 被引量:1
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作者 张福保 《Acta Mathematica Scientia》 SCIE CSCD 1998年第2期221-226,共6页
In this paper, mainly by means of the coincidence degree method, the existence of solutions for m-point boundary value problems at resonance of second order ordinary differential equations is discussed.
关键词 coincidence degree m-point bvp RESONANCE Caratheodory's conditions
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Existence and Uniqueness Results for a Fully Third-Order Boundary Value Problem
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作者 Xiaoming Liu Yongxiang Li 《Advances in Pure Mathematics》 2023年第8期495-503,共14页
The boundary value problems of the third-order ordinary differential equation have many practical application backgrounds and their some special cases have been studied by many authors. However, few scholars have stud... The boundary value problems of the third-order ordinary differential equation have many practical application backgrounds and their some special cases have been studied by many authors. However, few scholars have studied the boundary value problems of the complete third-order differential equations u′′′(t) = f (t,u(t),u′(t),u′′(t)). In this paper, we discuss the existence and uniqueness of solutions and positive solutions of the fully third-order ordinary differential equation on [0,1] with the boundary condition u(0) = u′(1) = u′′(1) = 0. Under some inequality conditions on nonlinearity f some new existence and uniqueness results of solutions and positive solutions are obtained. 展开更多
关键词 Fully Third-Order bvp SOLUTION Positive Solution Existence and Uniqueness Inequality Conditions
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