化工原理课程案例教学方法的初探

化工案例教学将化工生产过程中存在的实际问题经过提炼应用于课堂,使学生能够熟练地掌握化工原理的基本原理和典型设备,培养其实践能力和创新意识,可在一定程度上提高《化工原理》教学质量。基于作者几年的教学经验,文章主要就化工案例教学的实用性以及实施方法进行了探讨。     

XKAr-6-1型提氩装置产量质量影响因素分析

分析影响提氩装置产量质量的主要因素为：主塔工况稳定性、粗氩纯度、吸附器使用周期等,针对这些因素提出优化操作要点,使氩气产量质量超过设计水平。     

饲料级磷酸氢钙生产方法综述

综合评述了目前国内外饲料级磷酸氢钙生产和正在开发的各种工艺流程及生产方法。     

插层法制备硅酸盐层柱材料研究进展

本文概述了近年来以层状硅酸盐为前驱体采用插层法制备层柱材料的研究状况,分析了其热力学原理,介绍了硅酸盐层柱材料的主要用途,并对其今后的发展趋势做出了展望.     

Modeling of coupled mass and heat transfer through venting membranes for automotive applications

Experimental and theoretical approaches based on a mathematical model, have been developed to study the evolution of environmental parameters (temperature, total pressure, relative humidity, and water vapor partial pressure) inside a housing of an electronic device with a window containing a macroporous membrane. The model was based on the coupling of mass and heat transfer taking into account the effects of polarization of concentration in boundary layers. Membranes have been characterized by mercury porosimetry, liquid entry pressure measurements, scanning electron microscopy, and gas permeation. Once the model was experimentally validated, it was applied to investigate the influence of membranes on heat and mass transfer and to study the impact of the boundary layers on the global mass transport. The results demonstrated the importance of the membrane choice and dimensions to get the best temperature regulation and avoid water condensation inside an automotive electronic control unit (ECU). © 2008 American Institute of Chemical Engineers AIChE J, 2009     

Effect of propellant on the combustion synthesized Sr-doped LaMnO3 powders

Lanthanum strontium manganite (LSM) powders of composition La_0.7Sr_0.3MnO₃ are good candidates for cathode application in solid oxide fuel cells. This paper reports the synthesis of LSM powders from nitrate precursors by the combustion method, using two different propellants (urea and glycine) and varying the propellant/nitrate ratio. Thermogravimetric analysis (TGA) revealed two or three decomposition stages of the as-synthesized samples, with complete burn out of organics at about 850–900 °C. X-ray diffraction (XRD) patterns showed formation of only LSM phase for the sample synthesized with excess of urea, whereas SrCO₃ and MnCO₃ phases were also found for the samples prepared from glycine. The powder is better crystallized when a homogeneous gel is formed before burning. The crystallite size calculated using the Scherrer equation is in the range of 15–20 nm. Scanning electron microscopy (SEM) revealed the presence of agglomerates, formed by fine particles of different shapes.     

温和表面活性剂(英文)

尽管目前表面活性剂的品种有数千种之多 ,但已通过试验证实可用于个人保护用品配方中的表面活性剂却寥寥可数。主要原因是去污好的表面活性剂并非都温和 ,反之亦然。综述了目前已用于个人保护用品中的主要表面活性剂 ,并按a -SAA、n -SAA、z -SAA和c -SAA分类说明了这些表面活性剂在配方中的功能及其温和程度。同时阐述了影响表面活性剂刺激性 /温和程度的因素 ,以及如何改善a -SAA的温和性。还简述了表面活性剂温和性的试验方法     

煤气厂废水处理试验及分析研究

煤气厂发生炉煤气洗涤水循环使用,每天外排约２４０ｔ,废水污染物多、含量高。采用最新的ＳＢＲ新工艺活性污泥生物法后,废水处理实现达标排放与回用。     

A model for determination of residual stresses in plasma coatings

The main reasons for the formation of residual (internal tensile) stresses in thermal spraying methods are the large differences in the temperatures of particles of deposited material on the surface of the substrate, the specific volumes of these particles at the moment of contact with the substrate and in the cooled condition, and also the non-uniformity of the distribution of temperature over the cross-section of the coating. The theory of hereditary elasticity is used to develop a mathematical model of theoretical justification of the process of formation and redistribution of the residual stresses which takes into account the relationship between the stresses and strains in the contact – substrate zone in heating and also the changes of their strength properties. Analytical dependences of controlling the technological parameters, such as the time and heating temperature, are proposed.     

UV, Raman and XRD study of polymorphism of poly(methyl-n-propylsilane)

Raman, UV and XRD studies have been performed to characterize the structures of differently prepared samples of poly(methyl-n-propylsilane). The results demonstrate polymorphism of this polymer between T_c and T_g. At room temperature the polymer can exist in up to four modifications which comprise one amorphous disordered phase and three more ordered modifications, differing in the interchain organization and in the silicon backbone conformations. The latter are considered to be deviant, transoid and all-anti, respectively. The number of the modifications present and relative amount of each strongly depends on the preparation method and thermal history of the sample as well as on the molecular weight.