激光法合成SiC超细粉末物理化学过程的研究——Ⅰ.实验规律及粉末特性

用50W连续波CO_2激光器为热源,诱发SiH_4和C_2H_4反应,合成SiC超细粉末。实验确定了反应腔体内压力p、气源中的C/Si原子比、喷嘴内径2r以及激光功率密度与粉末特性之间的关系,并对合成的产物进行物理、化学表征。     

The growth and characterization of AlGaAs double heterostructures for the evaluation of reactor and source quality

AlGaAs double heterostructures are grown by low-pressure metalorganic chemical vapor deposition to evaluate the level of oxygen contamination in different trimethylaluminum sources. Effects of arsine purifiers, misoriented substrates, atmospheric exposure of the growth chamber, and possible phosphorus contamination are also studied. Extensive characterization is performed on these films by a variety of methods, including high-resolution x-ray diffraction, photoluminescence (PL), time-resolved photoluminescence, and secondary-ion mass spectrometry. The PL intensities for structures grown with the low-alkoxide grade are reproducibly much greater than those grown with the regular-grade TMA1. The use of AsH₃ purification improves the PL intensity.     

化工工艺计算机辅助设计

本文根据化工工艺设计的特点，阐述了化工工艺设计与ＣＡＤ的关系和开发研制计算机辅助化工工艺设计软件的思想，即将工艺设计、工艺图绘制与相关数据处理融为一体，并遵循这一构思，提出了软件开发研制的方法。     

A storage heat pump using an ‘ozone-friendly’ refrigerant

The paper describes the integration of a chemical and a vapour-compression heat pump for energy storage applications. The vapour-compression system is designed to operate using the UK cheap rate ‘Economy 7’ electricity tariff. The system is characterized thermodynamically using various refrigerant/absorbent pairs in the chemical storage circuit and an ozone-friendly refrigerant, R134a, in the vapour-compression circuit. Results indicate that the H₂O/Na₂S pair provides a high energy storage density and is the most suitable for use in this system. The paper also describes the design features of a domestic-sized version of this heat pump system. Air in the sunspace (conservatory) of a house was used as a heat source for the heat pump.     

Microstructural Effects of Ion Implantation on Molybdenum

The effects of ion implantation and subsequent annealing on the microstructure of molybdenum have been investigated by transmission electron microscopy. The ions investigated were carbon, nitrogen, and tellurium. The ion-induced damage was found to give rise to grain boundary migration phenomena both during implantation and during subsequent annealing. Precipitation or ordering was found to occur for each ion on annealing.     

Chemical States of Lanthanum in Carbonized La2O3-Mo Thermionic Cathode Materials

The chemical reaction between lanthanum oxide and molybdenum carbide was studied by thermodynamic calcu-lation, thermal analysis and in-situ X-ray Photoelectron Spectroscopy. The theoretical results show that at the environment allowing for the evaporation of lanthanum, such as in high vacuum, La2O3 in the La2O3-Mo materials can be reduced to metallic lanthanum by molybdenum carbide (Mo2C). To confirm the conclusion, many analysis methods such as XRD, SPS, and TG-DTA were taken. The experimental results show that the chemical state of lanthanum changes during heat-ing. It was proved, for the first time, that reacted metallic lanthanum appears at the surface of this kind of material at high temperature.     

化工企业环境因素的评价

化工企业环境因素评价是建立环境管理体系的核心任务，化工企业生产过程的特点决定了其环境因素数量多、环境影响大、识别评价难、控制难度大。本文介绍了化工企业环境因素评价的技术方法和过程，可以为提高环境因素评价的科学性、客观性和充分性提供参考。     

SISAK快速化学分离装置的建立

SISAK(Short-lived Isotopes Studies by the AKUFVE technique)技术是目前使用最广泛的快速化学分离方法之一,主要应用在短寿命核素的分离和鉴别、超重元素的人工合成以及化学性质研究等方面的工作中.本文简单地叙述了SISAK技术的流程、原理和发展现状,介绍了自行建立的国内第一套基于SISAK技术的快速化学分离装置,并通过从裂变产物中分离短寿命核素这一实例验证了SISAK技术在快速化学分离中的优越性.     

山药

山药是一种常用的中药，营养丰富，具有较高的药疗价值，现对山药的化学成分、药理作用、临床应用的研究进展作一介绍。