A Dual Phase Lag Model on Thermoelastic Interaction in an Infinite Fiber-Reinforced Anisotropic Medium with a Circular Hole

The model of generalized thermoelasticity proposed by dual phase lag (DPL), is applied to study the thermoelastic interactions in an infinite fiber-reinforced anisotropic medium with a circular hole. A decaying with time thermal field on the boundary of the hole, which is stress free, causes the thermoelastic interactions. The solutions for displacement, temperature, and stresses are obtained with the help of the finite element procedure. The effects of the reinforcement on temperature, stress, and displacement are studied. The exact solution in the case of isotropic medium is discussed explicitly. The accuracy of the finite element method validated by comparing between the finite element and exact solutions for absence the reinforcement.     

考虑资本闲置的多年时滞人力资本投入占用产出模型

人力资本理论强调的是由教育所新增的人力资本对经济增长的决定作用.为了规划与中国经济持续增长相适应的人力资本需求,建立了一个新颖的考虑资本闲置的多年时滞投入占用产出模型.为了考虑人力资本时滞长的特点以及人力资本占用的损耗补偿,在斯通人口投入产出模型和Leontief动态投入产出模型基础上,提出了多年时滞人力资本投入占用产出模型.将LDS模型推广为考虑资本闲置的多年时滞人力资本投入占用产出模型,以便考虑影响教育产出的外生因素,并推导出既适于产出增加也适于产出减少的正解.应用上,预测至2015年的各种教育水平人力资本的总量和部门需求,发现高级人力资本短缺和人才行业结构不合理是经济发展需要解决的重要问题.     

DYNAMIC CHARACTERISTICS OF LAG VIBRATION OF A WIND TURBINE BLADE

Lagwise dynamic characteristics of a wind turbine blade subjected to unsteady aero- dynamic loads are studied in this paper. The partial differential equations governing the coupled longitudinal-transverse vibration of the blade with large bending deflection are obtained by ap- plying Hamilton＇s principle. The modal problem of the coupled vibration is handled by using the method of numerical integration of Green＇s function. Influences of the rotating speed, the pitch angle, the setting angle, and the aerodynamic loads on natural frequencies are discussed. Results show that： （I） Lagwise natural frequencies ascend with the increase of rotating speed; effects of the rotating speed on low-frequencies are dramatic while these effects on high-frequencies become less. （2） Influences of the pitch angle on natural frequencies are little; in the range of the normal rotating speed, the first frequency ascends with the increase of the absolute value of the pitch angle, while it is contrary to the second and third frequencies. （3） Effects of the setting angle on natural frequencies depend on the rotating speed; influences are not significant at low speed, while they are dramatic on the first frequency at high speed. （4） Effects of the aerodynamic loads on natural frequencies are very little; frequencies derived from the model considering aerodynamic loads are smaller than those from the model neglecting aerodynamic loads; relative errors of the results corresponding to two models ascend with the increase of the absolute value of the setting angle.     

钢筋混凝土箱梁非线性及剪滞效应的试验研究

制作了钢筋混凝土简支箱梁模型,试验包括模型梁开裂范围内的加载及开裂后的加载。在开裂范围内,对该试验梁分别进行了顶板满布均布荷载、均布荷载作用于肋板上方、集中力作用于跨中以及对称集中力作用下的加载;对开裂后的试验梁,进行了对称集中力作用下的加载。用应变采集仪与电脑连接,并用半桥测量,温度自补偿方法测取应变值,采用百分表测试梁体挠度,采用读数显微镜观测裂缝。测量得到应力、应变的分布规律,验证了钢筋混凝土箱梁中存在剪滞效应。试验结果与考虑混凝土非线性的有限段法的计算结果吻合较好,验证了有限段法在混凝土箱梁剪滞效应分析中的适用性。     

Adaptive lag synchronization and parameter identification of fractional order chaotic systems

This paper proposes a simple scheme for the lag synchronization and the parameter identification of fractional order chaotic systems based on the new stability theory. The lag synchronization is achieved and the unknown parameters are identified by using the adaptive lag laws. Moreover, the scheme is analytical and is simple to implement in practice. The well-known fractional order chaotic Lü system is used to illustrate the validity of this theoretic method.     

基于改进DEA——以复相关系数为基准的滞后期的我国产业结构演化效率评价

为了评价我国的产业结构演化效率,本文构建了我国产业结构演化评价指标体系。针对传统DEA方法的局限性,文中引入以复相关系数为基准的滞后期,解决了产业结构演化评价中投入和产出之间的滞后性问题,建立更加有效的DEA改进模型,对我国产业结构演化效率进行评价。结论表明,各产业技术效率大部分时间大于规模效率,而且投入要素出现不同程度的冗余情况,近年来,第一、二产业固定资产投资和就业人员冗余程度有减轻的趋势,第二产业能源和水资源消耗较大,同时第三产业各要素冗余程度均有所加深。针对这一现象,本文提出了相关对策建议。     

带未知扰动的多涡卷混沌系统修正函数时滞投影同步

研究了带有未知外部扰动的不同多涡卷混沌系统修正函数时滞投影同步问题. 基于Lyapunov稳定性理论, 采用模糊自适应控制的方法设计自适应同步控制器及参数的更新规则. 该控制器在实现混沌系统修正函数时滞投影同步的同时对外界扰动的变化能保持较好的稳定性. 数值仿真的结果进一步验证了该方法的有效性.     

Adaptive generalized matrix projective lag synchronization between two different complex networks with non-identical nodes and different dimensions

<正>The adaptive generalized matrix projective lag synchronization between two different complex networks with non-identical nodes and different dimensions is investigated in this paper.Based on Lyapunov stability theory and Barbalat’s lemma,generalized matrix projective lag synchronization criteria are derived by using the adaptive control method.Furthermore,each network can be undirected or directed,connected or disconnected,and nodes in either network may have identical or different dynamics.The proposed strategy is applicable to almost all kinds of complex networks.In addition,numerical simulation results are presented to illustrate the effectiveness of this method,showing that the synchronization speed is sensitively influenced by the adaptive law strength,the network size,and the network topological structure.     

Two exact solutions of the DPL non-Fourier heat conduction equation with special conditions

This paper presents two exact explicit solutions for the three dimensional dual-phase lag （DLP） heat conduction equation, during the derivation of which the method of trial and error and the authors＇ previous experiences are utilized. To the authors＇ knowledge, most solutions of 2D or 3D DPL models available in the literature are obtained by numerical methods, and there are few exact solutions up to now. The exact solutions in this paper can be used as benchmarks to validate numerical solutions and to develop numerical schemes, grid generation methods and so forth. In addition, they are of theoretical significance since they correspond to physically possible situations. The main goal of this paper is to obtain some possible exact explicit solutions of the dual-phase lag heat conduction equation as the benchmark solutions for computational heat transfer, rather than specific solutions for some given initial and boundary conditions. Therefore, the initial and boundary conditions are indeterminate before derivation and can be deduced from the solutions afterwards. Actually, all solutions given in this paper can be easily proven by substituting them into the governing equation.     

箱梁剪滞翘曲位移函数的定义及其应用

提出了箱梁剪力滞效应计算中翘曲位移函数定义的新方法。由竖向弯曲荷载下箱梁截面的剪力流分布规律,定义符合箱梁各翼板剪切变形规律的剪力滞翘曲位移函数,该定义方法与箱梁剪力滞效应的力学定义完全吻合。通过对顶、底板具有不同厚度和内、外顶板具有不同宽度两种情况下的算例筒支粱在跨中集中力作用下的剪力滞效应对比分析,验证了基于剪切变形规律的剪滞翘曲位移函数对于箱梁剪力滞效应分析的精度和适用性。