硫酸铈和磷酸处理对铌酸表面酸度及催化活性的影响

用硫酸铈和磷酸对固体铌酸进行了表面处理。表面酸度和TG DTA测定结果表明 ,与未处理的固体铌酸相比 ,处理后表面强酸量提高 3～ 5倍 ,耐受温度由 30 0℃提高到 5 0 0～ 6 0 0℃。用于催化酯化合成二甘醇二苯甲酸酯增塑剂 ,处理后固体铌酸的催化活性和重复使用寿命有明显提高。     

我国内螺纹铜管的生产技术与发展方向

本文论述了我国内螺纹铜管业生产、工艺、产品技术条件、齿型及市场现状 ,提出了内螺纹铜管的研发方向。     

一类关于鲁棒性和敏感性的泛函的优化

本文给出了一类泛函的优化方法.这类泛函包括反映系统鲁棒性和敏感性的目标函数. 其优化是通过-Rm×n→Rm×n的映射来实现的.该映射将所有配置系统极点的反馈矩阵参数 化为一自由矩阵变量的函数.     

Novel Hyperbranched predominantly Alternating Copolymers Made From A Charge Transfer Complex monomer pair of p-(chloromethyl)styrene and Acrylonitrile via Controlled Living Radical Copolymerization

Summary Novel hyperbranched copolymers were successfully synthesized by the controlled charge transfer complex inimer and living radical copolymerization of p-(chloromethyl)styrene (PCMS) and acrylonitrile (AN). The resulting copolymers were characterized by SEC, NMR, FTIR, DSC and elemental analysis etc.. The influences of reaction conditions, such as the polymerization temperature, the catalyst (CuBr) concentration and the monomer ratio, on the resulting copolymers were investigated in detail. The monomer reactivity ratios were evaluated to be r_PCMS=0.937 and r_AN=0.088 respectively by the Fineman-Ross method. The higher are the polymerization temperature and the ratio of catalyst to monomer, the higher is the branching degree of the resulting copolymer. When the amount of monomer AN was used in excess than that of the monomer PCMS in the raw feed, the hyperbranched predominantly alternating copolymers HP[PCMS-co-AN] could be obtained. These hyperbranched copolymers were successfully used as functional macroinitiators to synthesize the star-shaped poly(PCMS-co-AN)/poly(MMA) block copolymers.     

Simulating Experiment for Temperature Field of Frozen Subgrade Using Regulation Tubes

The main factors that influence the temperature field of frozen subgrade were analyzed.The experimental equipment for simulating frozen subgrade was built up,and the declining regulating tubes were placed at the foot of the embankment. By means of this equipment two simulating experiments of controlling temperature filed of frozen subgrade were carried out in the laboratory. One method is to collect natural cold energy, and the other one is to collect natural cold energy ccompanied by artificial refrigeration simultaneously. The result indicates that the latter is an effective method for maintaining the stability of the frozen subgrade.     

多级网络多处理机系统的性能评估

本文建立了多级网络(δ-网)多处理机系统的马尔柯夫模型,为系统结构参数和任务粒度的选择提供了依据。文中分析了处理机数目、网络结构参数和任务粒度对系统性能的影响,并对模型计算结果和仿真结果作了比较。     

Ozonation of CI Reactive Black 5 using rotating packed bed and stirred tank reactor

This study investigates the ozonation of CI Reactive Black 5 (RB5) by using the rotating packed bed (RPB) and completely stirred tank reactor (CSTR) as ozone contactors. The RPB, which provides high gravitational force by adjusting the rotational speed, was employed as a novel ozone contactor. The same ozone dosage was separately introduced into either the RPB or the CSTR for the investigation, while the experimental solution was continuously circulated within the apparatus consisting of the RPB and CSTR. The decolorization and mineralization efficiencies of RB5 in the course of ozonation are compared for these two methods. Moreover, the dissolved and off‐gas ozone concentrations were simultaneously monitored for the further analysis. As a result, the ozone mass transfer rate per unit volume of the RPB was significantly higher because of its higher mass transfer coefficient and gas–liquid concentration driving force. Furthermore, ozonation kinetics was found to be independent of the gravitational magnitude of an ozone gas–liquid contactor. Therefore, the results suggest employing RPBs as ozone‐contacting devices with the advantage of volume reduction. The experimental results, which can be used for further modeling of the ozonation process in the RPB, also show the requirement of correct design for the RPB. Consequently, the present study is useful for the understanding of practical application of RPBs. Copyright © 2004 Society of Chemical Industry     

Nucleation of solidification in liquid droplets

Analytical and numerical methods have been developed to analyze the solidification kinetics of a mass of liquid droplets dispersed in a fluid or solid matrix using classical nucleation theory. The resulting analytical expressions and numerical calculations can be compared directly with calorimetric measurements of the droplet solidification exotherms to obtain information about the nucleation mechanism. With increasing contact angle at the solid-liquid-matrix triple point, the solidification onset, peak, and end temperatures and exothermic peak height all decrease sharply and the droplet solidification exotherms become broader. Decreasing either the droplet radius or the number of potential catalytic nucleation sites produces a similar but smaller effect. Distributions in droplet radius, contact angle, and nucleation sites have no effect on the solidification peak temperature, but the droplet solidification exotherms become broader and more symmetric. The solidification onset temperature is independent of cooling rate in the calorimeter, but the solidification peak and end temperatures decrease and the exothermic peak height increases with increasing cooling rate. Predicted droplet solidification exotherms are in excellent agreement with detailed experimental measurements on 10-nm-radius Cd droplets embedded in a solid Al matrix. Analytical predictions give best-fit values of 43 deg and 430 for the contact angle and the number of potential catalytic nucleation sites per droplet, respectively; numerical predictions give best-fit values of 43 deg and 750 for the contact angle and the number of potential catalytic nucleation sites per droplet, respectively.     

文件静态特性评估下的木马检测机制

本文提出了一种针对木马的静态信息进行分析的新的检测机制,建立了基于BP神经网络的数据处理模型。PE文件是Windows平台下的可执行文件,也是木马等后门程序的主要载体, 由于PE文件的结构复杂、灵活,而BP神经网络摸型的自身要求,导致数据的建摸过程遇到两个难点,本文首先引入了变化粒度的概念,解决了输入端非线性数据的问题。同时,也解决了将PE文件中大量的字符串归一化(0,1)区间)的问题,最终建立了一套较为理想的解决方案,取得了较为理想的测试数据。