Effect of molecular weight on two smectic polyesters

The liquid crystalline transitions of two kinds of smectic polyesters with different molecular weights were investigated by DSC, polarized microscopy and X-ray diffraction. The molecular weight affects the transitions significantly for these two kinds of polyesters. With a high enough molecular weight, both poly (pentamethylenep,p-bibenzoate) and poly(hexamethylenep,p-bibenzoate) exhibit an enantiotropic smectic phase, but the two endothermic transition peaks of the DSC heating curve seem to overlap. The polyesters tend to exhibit a monotropic smectic phase as the molecular weight decreases. From the DSC cooling curve, the isotropic-smectic transition can be seen more clearly. As the molecular weight decreases, the smectic order decrease significantly. The molecular weight affects the transitions in a different way for these two different kinds of polyesters.     

浸渍增重率和反渗率研究

对浸溃过程中浸渍剂沥青的浸入率和反渗率进行了分析与探讨。提出了理想增重率、理论增重率与实际增重率的概念和计算方法。并比较了实际增重率与操作增重率的差别。同时分析了抽真空的绝对压力与施压的绝对压力对各项增重率和反渗率的影响。     

硫化机网络群控系统

对硫化机群采用分散控制-集中管理式中央监控系统.系统分底层网络和上层网络两部分.底层网络分二级控制,采集现场硫化机温度、压力等参数.上层网络用于对生产数据进行处理显示、打印报表等.各层控制系统实现相对独立,该系统运行多年,未发生异常现象.     

Preparation and characterization of high-surface-area titanium dioxide by sol-gel process

One of the important ways to improve photocatalytic efficiency is to prepare catalyst with enhanced surface area. In this work, titanium dioxide (TiO₂) nanoparticles having enhanced surface area were synthesized under the interference of SiO₂. The mixed oxide, SiO₂-TiO₂ (10% mol% Si), was prepared by a sol-gel procedure using titanium tetra-n-butoxide as Ti-precursor. The commercial SiO₂ nanoparticles were added into the TiO₂ sols after hydrolysis. After condensation and calcination heat treatment, the SiO₂-TiO₂ nanoparticles were obtained. To achieve the purpose of obtaining the high-surface-area TiO₂, the SiO₂ was removed subsequently by aqueous NaOH solution. The TiO₂ products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), electron spectroscopy for chemical analysis (ESCA), and by N₂ adsorption-desorption isotherm. A fine mesoporous structure was formed for as-prepared TiO₂ after calcination at 400^∘C and the average pore diameter was about 7 nm. The porous TiO₂ products possess mixing phases of anatase and rutile. Phase transformation from anatase to rutile occurred when the samples were calcined. The phase transition temperature is sensitive to the silicon content. The particle size of ∼43 nm remained constant upon calcinations from 500 to 700^∘C. The specific surface area was increased up to 66% compared to regular TiO₂ samples that were prepared by the similar sol-gel procedure. The porous TiO₂ nanostructures exhibited enhanced photocatalytic performance to decompose methylene blue under UV irradiation.     

Effect of Cr3C2 on Valence-Electron Structure and Plasticity of Rim Phase in Ti(C,N)-Based Cermets

Based on the empirical electron theory of solids and molecules, the valence-electron structure (VES) of the rim phase in Ti(C,N)-based cermets was calculated, and the relationship between the VES and plasticity was determined. The results indicated that the plasticity of the rim phase in a Ti(C,N)-based cermet could be defined using the sum of the n _a values for the covalent bonds, and that chromium dissolution in the rim phase improved the plasticity of the rim phase. Moreover, a series of experiments showed that adding Cr₂C₃ to a typical Ti(C,N)-based cermet strengthened the interface. Based on those results, a Ti(C,N)-based cermet with added Cr₃C₂ was manufactured; the new cermet had more than twice the transverse rupture strength of a typical cermet.     

力化学法制备金属－NR硫化粘合用CSM－NR接枝聚合物

用开炼机，通过力化学方法，将ＮＲ／ＣＳＭ（质量比为１０／９０）制成４５￣＃钢－ＮＲ硫化粘合剂用接枝聚合物。当橡胶本体１００％破坏时，１８０°剥离强度为２３．６～２４．６ｋＮ／ｍ。     

废水处理中的复极性固定床电解槽技术

复极性固定床电解槽（bipolar packed bed cell,BPBC)是在三维电极原理基础上发展起来的新型电化学工程技术，其在治理含氰及重金属废水、有机废水和印染废水方面具有良好的处理效果。介绍了BPBC的电化学特性，综述了国内外BPBC废水处理技术应用现状及其机理研究的概况。同时，提出了该技术目前存在的问题，并对其进一步的深入研究作了展望。     

泥磷回收制磷危险性分析与防治

泥磷回收制磷属于化学危险品生产,由于黄磷本身的易燃特性和生产中其他因素的诱导,极容易发生泄漏引发火灾和灼伤。介绍了泥磷的产生和泥磷回收制磷的工艺特点。应用系统安全工程的原理和方法,辨识了泥磷回收制磷生产的潜在危险性;辨识了泥磷回收制磷生产过程中的物质危险性、装置危险性和工艺危险性。运用预先危险性分析法（PHA）对泥磷回收制磷的主要危险、有害因素进行分类和分级。根据对主要危险、有害因素分类和分级的结果,提出技术措施和管理措施来提高企业安全生产管理水平和预防生产性事故的发生。     

我国明矾石的物化性质及其在水泥中的水化硬化

本文系统地介绍了我国明矾石的地质成因、化学成份和矿物组成及其在水泥中的水化硬化,提出了明矾石在碱-硫酸盐激发下形成钙矾石的水化机理,综述了我国利用明矾石作为特种水泥、外加剂的原料及作为普通水泥的混合材所取得的应用成果。     

炭黑气力输送系统改造

介绍了炭黑气力输送系统的结构与工作原理。通过技术改造,解决了炭黑输送系统频繁堵塞,造成炭黑泄漏,污染环境的问题,降低了设备故障率,提高了产品质量,取得较好的直接、间接经济效益。