Mesopore development in PAN-ACF resulting from non-metal additives

The narrow pore-size distribution of activated carbon fibres (ACF) limits their application in the fields concerning larger molecules, such as liquid adsorption and catalyst support. On the addition of carbon particles and organic materials to polyacrylonitrile fibres, and after stabilizing and activating, the mesoporosity in the resultant ACF has been obviously increased. Among these additives, carbon black gives the best effect. With 1 wt% carbon black I in precursor and on activating at 880°C for 30 min, a mesoporosity of 48.2% (total pore volume 0.704 ml g-1, mesopore volume 0.340 ml g-1) has been obtained. The mechanism of mesopore formation is also discussed. This revised version was published online in November 2006 with corrections to the Cover Date.     

无线电引信多普勒信号增速器的研究

论述了无线电引信多普勒信号增速器的实现原理及意义，介绍了采用ＴＭＳ３２０Ｃ３０作为ＣＰＵ、多片大容量静态ＲＡＭ芯片构成海量存储体的信号增速器硬件结构和软件设计，并提出了今后的研究方向。     

开关DC—DC变换器并联运行问题的研究

开关直流电源并联运行在许多场合应用。每一路电源输出阻抗的不一致性使每一路输出电流难以均衡，影响了系统的可靠性。本文提出了一种双回路ＤＣ—ＤＣ变换器的控制方案。由于采用电压环（外环）和电流环（内环）两环结构的双回路控制模式，变换器输出电流得到了有效控制，便于多个ＤＣ—ＤＣ变换器输出直接并联，从而实现了模块化，具有一定的实用性     

论冶金企业节能管理员的技术要求

本文围绕冶金企业节能管理的工作内容和要求，论述了企业节能员应掌握的技术和提高技术途径。     

抓紧有利时机 搞好更新换代

本文简要回顾了１５０发动机发展历史，阐述了世界坦克动力发展现状，列举了几种对１５０ 继续发展的看法，认为从综合约束条件和高紧凑性考虑，仍以保持或适当减少缸径较优．指出当 前是追赶世界先进水平的极好时机，要牢牢把握住这个稍纵即逝的机遇．     

Memory-related changes of nitric oxide synthase activity and nitrite level in rat brain

The changes of nitric oxide synthase (NOS) activity and nitrite level in rat brain regions after spatial learning were investigated. NOS activity was assayed by conversion of [3H]L-arginine to [3H]L-citrulline, and a sensitive fluorometric assay for quantification of nitrite was used. Compared with sham-trained rats, NOS activity and nitrite level in hippocampus and cortex, and also the nitrite level in cerebellum, was elevated significantly one day after rats had learnt a water-rewarded spatial alteration task. These results suggest a spatial memory-related changes of endogenous NO in rat brain, and support the idea that NO participates in learning and memory processes.     

A genetic algorithm for multiple molecular sequence alignment

MOTIVATION: Multiple molecular sequence alignment is among the most important and most challenging tasks in computational biology. The currently used alignment techniques are characterized by great computational complexity, which prevents their wider use. This research is aimed at developing a new technique for efficient multiple sequence alignment. APPROACH: The new method is based on genetic algorithms. Genetic algorithms are stochastic approaches for efficient and robust searching. By converting biomolecular sequence alignment into a problem of searching for optimal or near-optimal points in an 'alignment space', a genetic algorithm can be used to find good alignments very efficiently. RESULTS: Experiments on real data sets have shown that the average computing time of this technique may be two or three orders lower than that of a technique based on pairwise dynamic programming, while the alignment qualities are very similar. AVAILABILITY: A C program on UNIX has been written to implement the technique. It is available on request from the authors.     

基于曙光1000A的并行查询核心系统的设计与实现

根据曙光１０００Ａ的特点，提出了查询核心系统的设计方案；经过分析比较，选定了数据划分方法，确定了ＳＱＬ子集。在此基础上，研究了物理库设计、并行事务管理、查询优化器的设计和事务的调度方法，旨在为在曙光１０００Ａ上建造并行数据库系统奠定基础。     

用于非均匀介质重建的选代算法收敛性的研究

研究轴对称二维非均匀介质重建迭代算法的收敛性问题。首先借助于玻恩近似将非线性积分方程线性化，然后，利用玻恩迭代法和变形玻恩迭代法，由散射场数据对轴对称二维非均匀介质进行重建。通过几个例子研究了影响迭代算法收敛性的几种因素，如送代算法本身、积分离散化后的网格划分、正则化方法中的正则化参数选取等。     

新型无灰分散剂的结构分析研究

通过薄膜渗析、红外光谱、凝胶渗透色谱、皂化反应等一系列手段建立了一套对无灰分散剂的系统分析方法，并利用该方法得到了一种新型无灰分散剂及其衍生物的平均结构、相对分子质量分布、分散度等重要结构信息，得出该新型无灰分散剂的结构与传统无灰分散剂的结构不同。