浅谈钢结构工程监理工作的要素

本文较详细地叙述了钢结构工程监理工作的主要过程及要素，分析了开工准备、工件制作、现场吊装和工程结尾等各阶段的重点工作和注意事项，对该项工作有一定的启示。     

渤西油田群供热方案的选择

本文对常用于油气田开发工程中的几种供热系统和供热介质作了系统、全面地分析与比较,旨在找出适合于渤西油气田群使用的供热系统与设备。     

CeO2∶Eu3+纳米晶的发光特性与Gd3+离子掺杂影响研究

以尿素为燃烧剂,采用低温燃烧法制备了Eu3+单掺杂和Eu3+、Gd3+共掺杂CeO2纳米晶粉末,用X射线衍射(XRD)和透射电镜(TEM)对样品进行了结构分析和形貌表征.对掺杂Gd3+离子的CeO2∶1％ Eu3+纳米晶的光谱研究发现,随着Gd3+离子掺杂浓度的增加,5D0→7F2跃迁与5D0→7F1跃迁的强度比随之增加,这表明Eu3++离子的格位对称性有所下降,且有利于提高红橙光的比例.鉴于CeO2基质在300～390nm有强吸收,Eu3+掺杂CeQ2纳米晶在近紫外激发LED荧光粉方面有潜在应用前景.     

电机械制动技术研究现状及其在轨道交通领域中的应用展望

目前,在轨道交通领域的制动系统主要以空气制动、液压制动、风阻制动和电磁制动等为主,电机械制动作为轨道交通领域发展的新方向,备受瞩目。该文从电机械制动技术的特征着手,结合国内外研究现状,着重对目前各领域、单位对电机械制动的研究方向及优缺点等方面进行介绍,并对电机械制动技术在轨道交通领域的发展前景进行展望。     

基于二阶差分的加权最小费用流相位展开算法

相位展开是光学干涉相位测量技术中的重要步骤,由于噪声、欠采样等因素的影响,精确的相位展开变得非常困难。将相位的二阶差分和最小费用流算法结合,提出一种以相位的二阶差分作为最小费用流权重的相位展开算法。模拟计算表明,该算法既可有效地避免枝切法由于连接的枝切形成闭合区域导致局部相位不能展开的问题,又可减小最小二乘法近似逼近带来的较大误差,相对于未设置权值的最小费用流算法,提高了其相位展开的精度。对三维形貌测量中的实验数据相位展开结果,证明了该算法的有效性。     

冶金系统首批工程硕士招生实践透析

经国务院学位办批准，冶金系统于1997年开展在职人员攻读工程硕士学位试点工作。此次试点工作集中在东北大学和北京科技大学进行。目前首批工程硕士招生工作已经结束，招收的297名学员开始课程学习。现对招生实际情况进行总结分析，以期对今后工作有所补益。     

渤西油田群电站方案研究对比

本文根据渤西油气田群的实际情况,就几种供电方式和几种发电机组进行了深入的分析与比较,选用了一种既经济又可靠的供电方式。     

Study on Spectral Overlap Model for Energy Transfer between J-Multiplets in Rare Earth-Doped Crystals

Based on the experimental data of KY3F10：Tm3^ reported by Dial, Kushida‘s spectral overlap model (SOM) of energy transfer between J-multiplets was studied. Firstly, with the help of the Inokuti-Hirayama and Yokota-Tanimoto models, the luminescence decay curve of ^3H4 of Tm^3 ion was fitted, and the fitted values of corresponding interaction parameters CDA of energy transfer and CDD of energy migration were obtained. Secondly, by compared with Kushida‘‘s SOM in which the relevant Judd-Ofelt approximative transition rates are known, the average overlap integrals of SOD and SDA were obtained. For S DD, how to treat the contribution of the electronic-dipole (ED) crystal field transition forbidden by C4v site symmetry in the calculation of SDD was discussed. For SDA we suggested that, by including the contribution of the phonon sidebands in the analysis of oscillator strength of transition, Kushida‘‘s SOM of ED-ED resonant energy transfer rate can be extended to non-resonant phonon-assisted D-A energy transfer. The strengths and widths of phonon sidebands in this example were discussed, and the results were reasonably good.     

Green,orange, and red upconversion luminescence in Nd^3＋/Yb^3＋： Cs2NaGdCl6 powders under 785 nm laser excitation

Nd^3＋：Cs2NaGdCl6 and Nd^3＋, Yb^3＋：Cs2NaGdCl6 polycrystalline powder samples were prepared by Morss method E. Under 785 nm semiconductor laser pumping, the upconversion luminescence of Nd^3＋ ions in Cs2NaGdCl6 was investigated at room temperature, and three upconversion emissions near 538 nm （Green）, 603 nm （Orange）, and 675 nm （Red） were observed and assigned to ^4G7/2→^4I9/2, （^4G7/2→^4I11/2; ^4G5/2→^4I9/2）, and （^4G7/2→^4I13/2; ^4G5/2→^4I11/2 ）, respectively. The dependences of these upconverted emissions on laser power and Nd^3＋ ion concentration were investigated, to explore the upconversion mechanism. The effect of doping Yb^3＋ ions on the upconversion luminescence of Nd^3＋ in Cs2NaGdCl6 was also studied under 785 nm laser excitation. The energy transfer processes were discussed as the possible mechanism for the above upconversion emissions.     

O'Z-EL型交流传动电力机车制动控制系统简介

O'Z-EL型交流传动电力机车装用的E.331型制动控制系统符合GSOST标准,文章介绍了E.331型制动控制系统的框架组成及主要部件,并针对制动系统各部件的功能、操作进行了说明,最后从部件组成、工作原理及具体性能参数方面阐述了自动制动、单独制动的制动性能。