结构阻尼模型及系统时域动响应

振动界对经典的非频变结构阻尼模型一直有种种争议,本文检查了它的前提并指出将该模型推广到系统时域动响应分析时导致的悖论.为了提供结构阻尼系统的时域动响应实用分析方法,文中分别提出了基于响应优势谱成份的粘性阻尼近似模型和基于粘弹性理论的三参数频变结构阻尼模型;它们既可逼近结构阻尼缓频变的特性,又可保证系统的时域动响应具有因果性.     

Piecewise analysis of oblique vibro-impacting systems

A great number of studies have shown the complex nonlinear dynamics of mechanical systems with repeated normal impacts. An oblique frictional impact introduces even more complicated dynamics such as stick-slip motions to those systems. Hence, the dynamics of oblique vibro-impacting systems with possible sliding motion is an open problem. Based on a hybrid analysis of vibro-impact dynamics, kinematics and complementary conditions, a piecewise analysis method is developed in the paper to describe the sliding motion during an oblique impact. Thereby, a parametrically excited planar pendulum between two parallel rigid walls is studied as an illustrative example. The example, together with the corresponding numerical results, shows that the sliding impacts occur in such a system with a set of properly selected parameters. The project supported by the National Natural Science Foundation of China (59905010) and by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Education, China     

动力学,振动与控制学科未来的发展趋势

对近年来动力学，振动与控制的研究进展作了简要回顾，概述了非线性动力学与振动主动控制这两个研究热点的现状，提出了世纪之初应关注的若干研究前沿，即高维非线性系统的全局摄动法，全局分岔和混沌动力学，高维强非线性系统分岔与混沌动力学的实验研究，非线性时滞系统的动力学，流体－弹性体－刚体耦合系统动力学与控制，碰撞与变结构系统动力学，微机电系统动力学。最后，对我国动力学，振动与控制的发展提出了一些建议。     

非半单分叉的Normal Form计算

在文［１］基础上，提出一种仅知道派生线性系统零实部特征值时求解非线性系统非半单分叉ＮｏｒｍａｌＦｏｒｍ的方法．通过适当的分类，将要求解的线性代数方程组分为若干相互独立的方程组．将所求系数向量按字典序列排列后，各独立方程组的系数矩阵是上三角矩阵．在非共振情形，各系数向量可按反字典序列递推求出．在共振情形，根据文中的二个定理，巧妙地由一简单的常数矩阵的最大秩子矩阵，定位其系数矩阵的满秩子矩阵，解决了这类方程组的降维简化．通过消元法，把简化后的方程化成类似于半单分叉ＮｏｒｍａｌＦｏｒｍ求解过程中方程的形式，其解法也类似．该方法非常易于在计算机代数软件平台上程序化．     

Principal parametric and three-to-one internal resonances of flexible beams undergoing a large linear motion

A set of nonlinear differential equations is established by using Kane‘s method for the planar oscillation of flexible beams undergoing a large linear motion. In the case of a simply supported slender beam under certain average acceleration of base, the second natural frequency of the beam may approximate the tripled first one so that the condition of 3 : 1 internal resonance of the beam holds true. The method of multiple scales is used to solve directly the nonlinear differential equations and to derive a set of nonlinear modulation equations for the principal parametric resonance of the first mode combined with 3 : 1 internal resonance between the first two modes. Then, the modulation equations are numerically solved to obtain the steady-state response and the stability condition of the beam. The abundant nonlinear dynamic behaviors, such as various types of local bifurcations and chaos that do not appear for linear models, can be observed in the case studies. For a Hopf bifurcation,the 4-dimensional modulation equations are reduced onto the central manifold and the type of Hopf bifurcation is determined. As usual, a limit cycle may undergo a series of period-doubling bifurcations and become a chaotic oscillation at last.     

电化学免疫传感器在食品安全检测中的应用进展

介绍了3种电化学免疫传感器的组装、构建,着重评论了近十年来其在食品安全检测中的应用研究,并对其前景进行了展望(引用文献30篇)。     

新中国航空事业的先驱者——张阿舟

张阿舟先生是我国著名的航空工程专家、固体力学家、教育家. 在20世纪后半叶,尤其是在新中国工业化初期的艰苦条件下,他面向我国航空工业发展需求,攻坚克难、培养后学,取得了突出成就. 本文全面回顾张阿舟先生的学术生涯, 介绍他在飞机结构强度、结构动力学、工程动力学反问题三个领域的主要学术贡献, 归纳他的治学特点. 文中介绍了张阿舟先生的航空报国情怀,以丰富的事例说明:他在主持新中国第一架飞机静力试验研究中发挥了核心作用, 在开拓我国飞机结构静/动强度等研究领域中发挥了引领作用, 在培养航空、力学领域的优秀人才中发挥了重要指导作用.      

液晶相位可变延迟器对自旋极化电子束极化方向的调制

讨论了液晶相位可变延迟器（liquid crystal variable retarder, LCVR）在自旋极化电子产生方面的应用.LCVR控制入射光子的偏振度，从而实现对自旋极化电子束极化方向的调制.采用LCVR代替1/4波片和Pockels盒的优点在于其对入射光方向不敏感，传输直径大，不需要机械转动即可大波长范围的延迟，且易于校准.另外，还研制了旋转检偏器，通过示波器读出，对光子偏振性进行检测并对LCVR进行校准. 关键词： 自旋极化电子源 液晶相位可变延迟器 极化方向     

uv-理论在一类半无限最小化问题的应用

Lemarechal,Oustry和Sagastizabal(2000)提出的uv分解理论为解决非光滑函数的高阶展开提供了一种新的途径，并将此理论应用于研究具有有限个约束的非线性规划的精确罚函数．本文将这一研究推广到具有无限约束的一类半无限规划的问题上，并给出了与这类最小化问题的精确罚函数的U-Lagrange函数有关的某些结果．