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。     

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。     

混合电解质NaBr+NaAc十H_2O体系的活度系数的测定

用电势法测定了298.15K以及I为0.1、0.5、1.0、1.5、2.0、2.5和3.0 mol/kg时,NaBr在混合电解质溶液NaBr+NaAc+H_2O中的活度系数.实验结果用Harned、SRJ和Pitzer方程拟合,得到各种方程的相互作用参数,由拟合的标准偏差得知,Pitzer方程的拟合精度略好于前2个方程.用Pitzer混合参数θ_(Br-Ac)和ψ_(Br-Na-Ac)计算了NaAc在该混合体系中的活度系数和体系的过量Gibbs自由能.     

水性涂料漆膜防霉效力测试若干问题的探讨

介绍了防霉剂防霉效力不同的测试方法以及国内外漆膜防霉性能测试的相关标准，提出了水性涂料漆膜防霉效力测试应采用人工环境长霉试验方法，探讨了国内外水性涂料防霉标准及测试方法中有待解决的问题。     

Measurement and modeling solubility of bioactive coumarin and its derivatives in supercritical carbon dioxide

To design a supercritical fluid extraction process for the separation of bioactive substances from natural products, a quantitative knowledge of phase equilibria between target biosolutes and solvent is necessary. How-ever, mostly no such information is available in literature to date. Thus in the present study, illustratively the solubility of bioactive coumarin and its various derivatives (i.e., hydroxy-, methyl-, and methoxy-derivatives) in supercritical CO₂ were measured at 308.15–328.15 K and 10–30 MPa. Also, the pure physical properties such as normal boiling point, critical constants, acentric factor, molar volume and standard vapor pressure for coumarin and its derivatives were estimated. By these estimated information, the measured solubilities were quantitatively correlated by an approximate lattice equation of state proposed recently by the present authors.     

可伸缩铰支管接头简介

本文指出了埋入地下的刚性管接头连接的管道易出现的问题及为解决这些问题而发明的可伸缩铰支管接头的特点及结构。