高效液相色谱法研究铝形态的可靠性

高效液相色谱法在铝形态的研究中发挥着举足轻重的作用,而铝形态的易变性和复杂性要求色谱条件无侵入性和检测手段具有形态选择性。文中列举了若干实例说明高效液相色谱法在铝形态分析中的常用方法和注意事项。     

The Analysis of Network Scale and Reliability in Ring-and-Tree-Based Metro-Access Network with LAN Service

In this article, a (ring-and-tree)-based metro-access network architecture is proposed. By using some conventional optical components, the network can realize passivity in both a remote node and optical network unit (ONU). By employing ring-and-tree topology, the network cannot only provide protection for feeder fibers, but also realize large-scale access. By connecting the ONUs into a ring, the network cannot only carry out mutual protections between ONUs, but also support LAN-service transmission. The analysis of system performance demonstrates the effectiveness of the architecture.     

含时耦合谐振子体系的动力学演化

利用含时量子变换理论,给出含时双模耦合谐振子的严格解.并根据这一结果,对于给定的初态为Fock态和相干态情形,讨论了其动力学演化.     

RESEARCH ON AMSAA-BISE MODEL—AN ANSWER TO MEI MEN-HUA

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎＭＥＩＷｅｎ＿ｈｕａ’ｓｐａｐｅｒ [1 ] ,ａｃｏｍｍｅｎｔｏｎＡＭＳＡＡ＿ＢＩＳＥｍｏｄｅｌｐｒｏｐｏｓｅｄｂｙａｕｔｈｏｒｅｔａｌ.(ｃｆ[2 ] )ｉｓｇｉｖｅｎ ,ａｎｄａｎａｐｐｒｏｘｉｍａｔｅｍｏｄｅｌａｔｔｅｍｐｔｉｎｇｔｏｓｏｌｖｅｔｈｉｓｐｒｏｂｌｅｍｉｓｐｒｅｓｅｎｔｅｄ .ＴｈｅＡＭＳＡＡ＿ＢＩＳＥｍｏｄｅｌｉｓｄｅｒｉｖｅｄｄｉｒｅｃｔｌｙｆｒｏｍａｎｏｔｈｅｒａｐｐｒｏａｃｈｔｈａｔｉｓｄｉｆｆｅｒｅｎｔｆｒｏｍｔｈｅａｐｐｒｏａｃｈｅｓｏｆ[2 ]ａｎｄ [3 ]…     

Mathematical Modeling of Time-Dependent Aerodynamic Loads on an Airfoil with Dynamic Deflection of a Control on the Trailing Edge

The linear problem of the time-dependent inviscid flow past a thin symmetric airfoil with a control on its trailing edge deflected in accordance with an arbitrary law is considered. The aerodynamic loads on the airfoil are calculated. The intensity of the vortex wake shed from the airfoil is determined by numerically solving a Volterra integral equation of the first kind. Questions of the mathematical modeling of the time-dependent aerodynamic loads in a form convenient for the joint solution of the problems of aerodynamics and flight dynamics are also considered. The results of the modeling are compared with the numerical solutions obtained.__________Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, 2005, pp. 157–169.Original Russian Text Copyright © 2005 by Khrabrov.     

捷联式惯性部件冗余设计

一本文以航天领域中卫星上惯性敏感部件的应用为背景，对捷联式陀螺和加速度计的冗余设计进行了分析和研究，得出在待测三维姿态量的平均方差最小意义上的陀螺和加速度计的几何最优安装结构；并对这几种配置方案的非故障模式和故障模式（包含临界故障模式）所能达到的精度指标进行了分析和推导，并同常规的非冗余正交安装方案进行了对比；此外，对这几种配置方案在温备份和热备份工作状态下的可靠性指标的计算公式进行了推导，并给出了相应的应用条件。     

A computational method for first-excursion reliability

An efficient computational method is suggested for the first-excursion reliability assessment of nonstationary process. In the proposed method, the nonlinear performance function is linearized at the Hasofer-Lind point obtained by an iterative algorithm. The problem of the nonstationary processes is solved by the discrete-time method, in which the precision can be controlled by choosing the steps of discretization. The derived formulae can be conveniently degraded to calculate both the first-excursion reliability with linear performance function of stationary processes and the time-independent reliability. The suggested method is useful for the analysis of components and systems with nonstationary responses in structural design where some uncertainties are represented by a vector of nonstationary processes. Examples are given to demonstrate the fast convergency and effectiveness of the presented method. The project supported by the National Natural Science Foundation of China     

Extrusion of a compressible Newtonian fluid with periodic inflow and slip at the wall

We explore a mechanism of extrusion instability, based on the combination of nonlinear slip and compressibility. We consider the time-dependent compressible Newtonian extrudate swell problem with slip at the wall. Steady-state solutions are unstable in regimes where the shear stress is a decreasing function of the velocity at the wall. Compressibility provides the means for the alternate storage and release of elastic energy, and, consequently, gives rise to periodic solutions. The added novelty in the present work is the assumption of periodic volumetric flow rate at the inlet of the die. This leads to more involved periodic responses and to free surface oscillations similar to those observed experimentally with the stick-slip instability. To numerically simulate the flow, we use finite elements in space and a fully-implicit scheme in time.Dedicated to the memory of Prof. Tasos Papanastasiou     

基于线抽样的可靠性灵敏度分析方法

提出了一种基于线抽样的可靠性灵敏度分析方法.线抽样可靠性分析中,结构失效概率Pf是由每个抽样样本对应的失效概率Pfj的算术平均值来计算的,由此可知Pf对基本变量分布参数θ的灵敏度(э)Pf/(э)θ可以表示为Pfj对θ的偏导数(э)Pfj/(э)θ的算术平均值,而(э)Pfj/(э)θ则可以很容易地由Pfj与基本变量分布参数θ的解析关系求得. (э)Pfj/(э)θ和(э)Pf/(э)θ的计算公式被详细推导.可靠性灵敏度分析的线抽样方法继承了线抽样法的优点,诸如精度高,收敛快且适用于高维及多模式情况等.这些优点由算例证实.