La_2Ti_2O_7的合成与结构分析

本文用四氯化钛、三氧化二镧为原料,以氨水为碱性物质,用共沉淀法,在pH为8.5—10范围内,得到了镧和钛的氢氧化物共沉淀,经过滤、洗涤、干噪、并在1100℃灼烧1小时,得到La_2Ti_2O_7晶体。产品属单斜晶系,P_(21m)空间群。晶体具有类钙钛矿结构,其中钛以四面体同氧原子配位。扫描电镜观察,产品呈椭球形、粒度均匀,大小为0.2—0.5μm。差热结合X—射线分析表明、产品首先以非晶态出现,在850℃左右结晶。本文还就pH、灼烧温度、灼烧时间等对产品的影响作了详尽的研究。     

新型稀土Te-Cu合金的抗氧化性能

将纯铜、Te-Cu合金、新型稀土Te-Cu合金放入马弗炉中加热氧化,通过绘制氧化动力学曲线、氧化皮金相组织观察、断面金相观察、X-ray分析,研究新型合金的抗氧化性能.结果表明,合金的氧化动力学曲线大致遵循抛物线规律;新型合金在600、800 ℃时具有比纯铜和Te-Cu合金更好的抗氧化性能;新型合金氧化膜的黏附性能优于Te-Cu合金;氧化膜中出现了除Cu2O、CuO外的新相;新型合金抗氧化性能的提高是元素Te和Ce共同作用的结果.     

散装水泥贮运集装箱研制报告

针对传统的水泥包装、贮运方法存在水泥损耗量大，水泥质量下降，污染环境等问题，研究用水泥贮运集装箱贮运水泥。实际应用表明，这种贮运集装箱的贮运效果远优于传统的水泥包装、贮运方法。     

197例广东教育学院学生性心理初步调查

通过对广东教育学院学生性心理进行问卷调查，根据调查的数据进行了分析和讨论，提示各类大、中学校进行性知识、性道德教育是非常必要的。     

Non-LTE恒星大气模型完全线性化原理

通过对Ｎｏｎ－ＬＴＥ的平面平行状恒星大气结构的数值模型完全线性化方法工作原理的介绍，阐述了恒星大气理论的工作原理和一般方法，重点说明了恒星大气数值方法的工作特点。     

高效快速多种燃气组分色谱分析法

采用热导检测器，通过几种柱的组合．采用多维柱切换系统，并自动完成阀的驱动和信号切换，实现性质不同的人工煤气和液化石油气主要成分一次进样全自动分析，该方法操作简便、分离效果好、灵敏度高、结果准确可靠．     

双周期Riemann边值问题解法的一个注记

解析函数的边值问题是复变函数的重要分支。许多工程技术、力学物理问题可转化为此类问题或奇异积分方程，而后者的求解又与这类问题有着密切的联系，因此它有广泛的应用价值。本文讨论了当G*∈L时双周期Riemann边值问题的求解方法与可解条件。     

Elementary Investigation of Increasing Polarization Performance of Air Electrode for CO2 Transfer

Air electrodes are the key components of Electrochemical carbon dioxide concentrating(EDC) cells. Therefore, the improvement of the polarization performance is beneficial to the increasing of CO2 transfer and cell stability .The preparing process of air electrode is improved by means of the pretreatment of active carbon(AC) and the selection of preparing method of platinum/carbon(Pt/C) powders. Besides, based on the analysis of orthogonal test results, the optimum preparing conditions of Pt/C powders in air electrode are achieved, that is, hydrazine hydrate concentration is 5%～10%, platinum capacity is 8mg/cm2, chloroplatinic acid concentration is 10.0mg/ml and water both temperature is 40℃.     

Value of Access to Jobs and Amenities: Evidence from New Residential Properties in Beijing

<正>Introduction When households are faced with the choice of where to live in a city, one of the foremost concerns is the loca-tion’s accessibility to jobs and various other amenities, such as schools, hospitals, and parks[1]. A home in a city is a gateway to urban opportunities, and obviously     

Electrooxidation of Mn(Ⅱ) on Pb-Sb-As Electrode in Sulfuric Acid

The electrooxidation of Mn(Ⅱ) on Pb-Sb-As alloy electrode in sulfuric acid has been investigated.In order to make the two steps of indirect electrosynthesis of benzaldehyde carried out in the same sulfuric acid concentration and also obtain high current efficiency of Mn(Ⅱ) to Mn(Ⅲ) and high yield of Mn(Ⅲ) oxidizing toluene to benzaldehyde in the mean time,the electrooxidation of Mn(Ⅱ) in 60% H2SO4 has been studied.Experimental results show that high current efficiency of Mn(Ⅲ) (about 75%) is obtained in 60%H2SO4 at 60℃.The reason affecting the current efficiency of Mn(Ⅲ) is discussed,and it is the coordination of sulfuric acid concentration and electrolytic temperature.The law is found that it is suitable for electrolysis at low temperature when sulfuric acid concentration is low and at high temperature when sulfuric acid concentration is high.