Buckling of Columns with Intermediate Elastic Restraint

This paper presents a comprehensive set of exact stability criteria for Euler columns with an intermediate elastic restraint. A subset of this class of problem is the buckling problem of columns with an intermediate rigid support where the elastic restraint takes on an infinite stiffness. Also, this study reiterates the existence of a critical elastic restraint stiffness in which the buckled mode switches to a higher-buckling mode of the corresponding column without an intermediate support. It is clear that this critical stiffness value exists only when the restraint is placed at the node of the higher-buckling mode and the buckling load associated with this critical stiffness value is the maximum achievable value that can be attained with an intermediate elastic restraint.     

电子应用产品的防电击试验浅析

本文依据国家有关标准对电子应用产品的防电击试验进行了简介和分析，指出了试验中应注意的问题。     

Artificial added mass instabilities in sequential staggered coupling of nonlinear structures and incompressible viscous flows

Within this paper the so-called artificial added mass effect is investigated which is responsible for devastating instabilities within sequentially staggered Fluid-structure Interaction (FSI) simulations where incompressible fluids are considered.A discrete representation of the added mass operator M_A is given and ‘instability conditions’ are evaluated for different temporal discretisation schemes. It is proven that for every sequentially staggered scheme and given spatial discretisation of a problem, a mass ratio between fluid and structural mass density can be found at which the coupled system becomes unstable. The analysis is quite general and does not depend upon the particular spatial discretisation schemes used. However here special attention is given to stabilised finite elements employed on the fluid partition. Numerical investigations further highlight the results.     

Author's reply to “Comments on ‘Performance evaluation of UKF-based nonlinear filtering”’

It is stated in the above-mentioned comment that the main result of the paper Xiong, Zhang, et al. [(2006). Performance evaluation of UKF-based nonlinear filtering. Automatica 42(2), 261-270] can be extended to a class of filters, such as the extended Kalman filter (EKF). As we show here, this belief can be justified in a rigorous way, even for the nonlinear stochastic system with a nonlinear measurement equation.     

On stability of second-order quasi-polynomials with a single delay

In this note the stability of a second-order quasi-polynomial with a single delay is studied. Although there is a vast literature on this problem, most available solutions are limited to some particular cases. Moreover, some published results on this subject appear to contain imprecise, or even wrong, conditions. The purpose of this note is to show that by accurate application of known theories, a complete explicit characterization of stability regions can be derived in a most general case. As a byproduct of the proposed analysis, we show that in the high-order case the quasi-polynomial is delay-independent unstable whenever its delay-free version has an odd number of unstable roots (or, equivalently, a negative static gain).     

The Stability of Runge－Kutta Methods for Systems of Delay Differential Equations

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塔式起重机载重滑轮组的稳定性研究

对塔式起重机载重滑轮组的稳定性进行了深入讨论并推出了各参数之间的关系式以及My对稳定性的影响。另外,还提供了具体的实验数据。     

三峡永久船闸中隔墩卸荷松弛特征研究

本选取三峡水利枢纽永久船闸二闸室桩号15 583代表性断面，通过地表测绘与地质编录、钻孔勘探、压水试验、全孔壁数字成像，物探测试，弹性模测试等综合勘察手段，并结合岩体变形监测成果等，查清了中隔墩岩体的工程地质特征，岩体卸荷松驰范围、物理力学性质及其稳定性。     

掺镉纳米SnO2的热稳定性,电导及气敏性能

本文研究了ＣｄＯ掺杂对纳米ＳｎＯ２粉料的热稳定性，电导及气敏特性的影响。结果表明，以非晶状态均匀分散在ＳｎＯ２颗粒表面的ＣｄＯ能阻止ＳｎＯ２之间的相互扩散，提高了纳米ＳｎＯ２的热稳定性；固溶于ＳｎＯ２昌粒中的ＣｄＯ量（Ｃｄ／Ｓｎ〈０．０５）很小，但对元件的电导影响显著；纳米级的晶粒尺寸（〈６ｎｍ）及ＣｄＯ的掺杂大大改善了ＳｎＯ２的气敏特性。     

一种新型无突变自动高压电源

本文介绍一种新型高压直流电源，它的输出高压的提升、下降均自动、无级、缓慢地变化，无突变现象，尤其在电网供电突然中断时，也能使用高压自动、缓慢地下降到０。它用于半导体放射性射线探测器，可以避免由于操作的粗心或电网供电突然中继引起高压快速变化或而产生的对该类昂贵探测器及其附件的损害，使探测器的优良性能得以保持。