椭球反射镜膜厚均匀性

本文分析了椭球反射镜膜层厚度均匀性对反射率的影响,从理论上得到膜厚计算公式。根据计算的膜厚分布设计了遮蔽板,获得较好的反射特性。     

底敞口充气浮箱研究和试验

提出底敞口充气浮箱的结构和概念。经模型模拟试验研究分析，经典浮力定律可用于这种浮箱的浮力计算；其动充气状况还具有一定的允许伤损面积。它的研究将为水陆两用车辆增大浮力，缩小外形，提高水上自下而上能力和潜驶潜伏提供具有诱惑力的工程应用前景。     

准分子激光器异步感应密封传动技术

一种新型准分子激光器循环系统中的密封传动技术，具有可耐高气压，不失耦，不使用昂贵强磁材料，结构简单等优点，虽有涡流损失过大之不足，但能很好地适用于小功率下运行。     

二烷基硫代磷酸铵的捕收性能

本文研究了二烷基硫代磷酸铵（ＲＯ）２ＰＳＯＮＨ４（Ｒ＝乙基、丁基、己基、烯丙烯）系列捕收剂对非硫化矿孔雀石、锡石、赤铁矿、白铅矿、方解石和菱锌矿的浮选性能，并就药剂结构与性能关系进行了分析讨论．     

Structure and damping properties of polydimethylsiloxane and polymethacrylate sequential interpenetrating polymer networks

By using the technology of the sequential interpenetrating polymer network, a series of novel damping materials based on a polydimethylsiloxane (PDMS)/polyacrylate (PAC) matrix with polymethacrylate (PMAC) were synthesized. They have a controllable broad transition peak spanning the temperature range of 150–220°C and the medial value of loss factor with maximum of 0.35–0.60. Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and atomic force microscopy (AFM) were applied to analyze and characterize the transition behavior and the microphase structure of the materials. It was found that the size and height of a transition peak at both the low‐ and the high‐temperature zones change as a function not only of the concentration of PMAC and PDMS but also of the kind of PMAC; simultaneously, the low‐ temperature behavior was also governed by the crystallization of PDMS. The content of the crosslinking agent exerts a significant influence on the configuration of the curves of the transition peaks. AFM shows a characteristic phase morphology of double‐phase continuity containing a transition layer and domain less than 1 μm, indicating that the interwoven multilayer networks are the key to incorporation of the immiscible components and form a broad damping functional region. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 545–551, 2002     

Quantum-mechanical reaction rate constants from centroid molecular dynamics simulations: Barrier crossing in an asymmetrical double-well

Quantum-mechanical reaction rate constants were calculated from centroid molecular dynamics (CMD) simulations, for the case of barrier crossing in an asymmetrical double-well potential bilinearly coupled to a harmonic bath. The calculation is based on a recently proposed formulation of the reaction rate constant in terms of the position—flux correlation function, which can be approximated via CMD in a well-defined manner. The predictions of CMD and various simplified versions of it are compared to exact results, which were obtained via the quasi-adiabatic propagator path integral (QUAPI) method, and/or path integral quantum transition state theory (PI-QTST). The predictions based on CMD are found to be in good agreement with both.     

基于小波基优化和动态比特分配的数字音频压缩编码方案

提出了一种新颖的基于自适应小波基优化选择和心理声学模型相结合的数字音频信号的透明质量编码方法，保证固定失真水平上使每帧信号的变换系数的动态分配的比特数最少，并且利用动态码本的方法来消除音频信号的统计冗余，进一步压缩比特率，对于抽样率为４４．１ｋＨｚ每样值用１６比特线性码表示的光盘单声道音乐信号可以压缩到６４ｋＢＰＳ左右。     

Hydrothermal Synthesis of Acicular Lead Titanate Fine Powders

A pure, acicular lead titanate (PbTiO₃) fine powder with a white color has been prepared by hydrothermal synthesis. It is a new phase of PbTiO₃ with I 4 symmetry, cell parameters of a = 12.358 Å and b = 14.541 Å, and a density of 6.80 g.cm⁻³. The influences of pH (12.5 to 14.4), Pb/Ti ratio (1.0 to 1.6) in the feedstock, reaction temperature (130° to 230°C), time (0.25 to 4 h), starting materials, and additives on the formation of acicular PbTiO₃ under hydrothermal conditions have been investigated. The acicular PbTiO₃ with I 4 symmetry, referred to as the PX phase, can be converted to the perovskite-type (PE phase) of PbTiO₃ at about 605°C while its acicular morphology is essentially unchanged. The preferable conditions for preparing pure acicular PX-phase PbTiO₃ are that the pH is 13.0 to 14.0, Pb/Ti ratio is >1.3, reaction temperature is 170° to 200°C, time is 0.5 to 1.0 h, titanium butoxide (Ti[O(CH₂)₃CH₃]₄) is the starting material, and poly(vinyl alcohol) is an additive. The acicular grain of the PX phase is usually less than 100 nm in diameter and more than 1000 nm in length.     

界牌水电厂1号发电机定子改造铁损试验

针对界牌水电厂1号发电机多次出现的定转子轻微扫膛现象,对其进行检修,详细介绍了改造后的定子铁损试验前的准备、试验方案的确定、试验过程以及试验结果。图2幅,表2个。