路易斯·康的几何学

该文通过对路易斯·康的设计手法的分析,认为其几何学构成中加法重于减法。路易斯·康在其空间单元概念形成之后,几乎所有的建筑设计手法均围绕着如何丰富这种空间单元的表现。路易斯·康对艺术与自然的区分,使得地形要素在其建筑构成中多半是辅助性的。     

公共性住宅,洛杉矶

文章简要介绍了马宅的加建设计。与惯常做法不同的是,住宅的加建部分以一种积极的姿态重新定义了原有建筑。     

A comparison of several reanalysis methods for structural layout modifications with added degrees of freedom

The goal of this paper is to compare several reanalysis methods for structural layout modifications with added degrees of freedom. These methods include the modified initial analysis methods, the modified initial analyses method with a scalar multiplier, and the preconditioned conjugate gradient method. These reanalysis methods are compared in terms of condition numbers of the preconditioned system and their computational accuracy. It is concluded in this paper that the preconditioner of the first method is not positive definite in general, while for the second method a positive definite preconditioner for a small scalar multiplier can be obtained, but the condition number of the preconditioned system is still large. For the third method, the condition numbers of the preconditioned system are significantly reduced, and highly accurate approximate solutions can be obtained in a few iterations.     

N-氨丙基吗啉合成研究

以吗啉和丙烯腈为原料,经加成、催化加氢和精制过程生产N-氨丙基吗啉,考察了催化剂种类及用量、原料配比、反应温度、压力、时间等因素对反应的影响,确定了最佳工艺条件为n(丙烯腈)∶n(吗啉)=1.0∶1.05,反应温度40℃,反应时间5~5.5h,加成收率99%以上,精制后中间产物质量分数99%;采用粉末金属钴为催化剂,w(催化剂)=2%,质量分数25%氨水为助催化剂,w(助催化剂)=50%,反应温度150℃,反应压力4.0 MPa,反应5h,加氢收率88%以上,精制后产品质量分数99.7%。     

超厚铜(343μm)PCB的制作工艺探讨

随着电子技术的不断发展,PCB上集成的功能元件数越来越多,对线路的电流导通能力和承载能力的要求越来越高,线路板的铜厚会越来越厚,而能够提供大电流和将电源集成的超厚铜(343μm及以上)印制电路板将逐渐成为今后线路板行业发展的一个趋势,在未来的电子领域中前景广阔。本文主要针对343μm超厚铜箔PCB的制作工艺进行研究,采用逐层叠加的方法,以铜厚137.2μm的底铜板料制成了成品铜厚达到μm的印制电路板,文章分析和讨论了几种制作工艺的可行性,同时对影响超厚铜箔印制板质量的关键工艺控制点进行了研究,通过改进和优化,进而找出了理想的工艺路线和工艺条件。     

偏心介质棒加载圆波导模式分析

本文基于柱谐基函数展开,对偏心介质棒加载的圆波导模式进行分析.利用Bessel函数的加法定理,在边界上进行场匹配,获得关于诸传播常数K_z的方程.对方程进行级数截断后,可以方便地解出该波导的各种传播模式,具有收敛性可靠,结果精确、计算量小的特点,比PMM和LSBRM更为可靠易行.     

Aqueous Ozonation Of Fatty Acids

The reactivity of a series of fatty acids toward ozone was examined in aqueous solution at low substrate concentration (μg.L^?1 range). Saturated fatty acids were unreactive, unsaturated fatty acids were readily consumed. A number of reaction products or their methylated derivatives were identified by gas chromatography and gas chromatography-mass spectrometry. The products identified are consistent with a 1,3-dipolar cyclo-addotion reaction.     

应用精细积分法的结构MBC状态方程求解

基于市场机制控制(Market-Based Control,MBC)属于分散控制,以往求解状态方程都采用差分类的近似,有时由于计算存在较大误差,不能得到结构真实状态的精确响应。精细积分法以其高精度、无条件稳定等优点被广泛的应用。文中引入两种精细积分方法,将精细积分的思想运用到基于市场机制(MBC)控制算法的求解中,推导了两种基于MBC控制状态方程的精细递推格式,大大提高了计算的精度及算法的稳定性,并且比较了两种精细积分方法的优缺点。最后通过算例,说明了采用精细积分方法计算MBC控制的必要性及有效性。     

Size reduction of PtRu catalyst particle deposited on carbon support by addition of non-metallic elements

Addition of non-metallic elements such as N, P and S was examined to reduce the catalyst particle size of PtRu deposited on a carbon support and to improve the catalytic performance. It was found that the addition of N, P and S reduced the size of PtRu catalyst particle and that P was the most effective additive on the size reduction. A well dispersed PtRu catalyst particle 2 nm in size was obtained by the addition of P. The maximum power density was observed to be 64 mW/cm² in a passive state of direct methanol fuel cell (DMFC) at room temperature by using the PtRuP anode catalyst. The PtRuP catalyst retained the size independently with surface area of the carbon support. This made it possible to use a carbon support with low surface area (lower porosity), resulting in better accessibility by molecules on the noble metal particles which were deposited prior to the external surface in compared to the micropore walls. The maximum power density was improved from 44 to 64 mW/cm² by using a less porous carbon support (140 m²/g).     

一种加锑减锡的铜基减摩材料的研制

在6－6－3青铜基含油轴承的基础上，进行了减锡加锑的试验，研制出了符合ZBW90002—88要求性能以锑部分代替锡的新合金，为节约锡资源、开辟锑的应用领域指出了一条新途径。