催化裂化干气回收乙烯用于制备环氧乙烷的研究

叙述了在YS型银催化剂作用下，利用催化裂化干气回收的乙烯制备环氧乙烷的实验研究。结果表明：在银催化剂上催化氧化生成环氧乙烷的过程中，使用回收的乙烯，催化剂的初选择性可达80％；在保持环氧乙烷时空产率不变，经过2000h催化剂稳定性试验后，选择性下降了3—4个百分点，反应温度上升约10℃，与用聚合级乙烯为原料进行比较，催化剂初选择性低2—3个百分点、稳定性略差。该结果为用回收乙烯生产环氧乙烷提供了试验依据。     

Preparation and gas-sensing characteristics of nanocrystalline spinel zinc ferrite thin films

Zinc ferrite is a promising sensor material. In this paper, thin films of nanocrystalline zinc ferrite were deposited on alumina substrates by nebulization of a 0.01-M solution of a mixture of ZnCl/sub 2/ and FeCl/sub 3/ in ethanol (Zn:Fe=1:2) followed by pyrolysis and annealing in flowing air. The resulting films were characterized by X-ray diffraction and scanning electron microscopy, and the gas-sensing properties of as-deposited films were also investigated.     

A practical SPICE model based on the physics and characteristics of realistic single-electron transistors

A practical model for a single-electron transistor (SET) was developed based on the physical phenomena in realistic Si SETs, and implemented into a conventional circuit simulator. In the proposed model, the SET current calculated by the analytic model is combined with the parasitic MOSFET characteristics, which have been observed in many recently reported SETs formed on Si nanostructures. The SPICE simulation results were compared with the measured characteristics of the Si SETs. In terms of the bias, temperature, and size dependence of the realistic SET characteristics, an extensive comparison leads to good agreement within a reasonable level of accuracy. This result is noticeable in that a single set of model parameters was used, while considering divergent physical phenomena such as the parasitic MOSFET, the Coulomb oscillation phase shift, and the tunneling resistance modulated by the gate bias. When compared to the measured data, the accuracy of the voltage transfer characteristics of a single-electron inverter obtained from the SPICE simulation was within 15%. This new SPICE model can be applied to estimating the realistic performance of a CMOS/SET hybrid circuit or various SET logic architectures.     

北京火车站抗震鉴定与加固技术

北京火车站是首都重要的标志性建筑之一 ,195 9年建成 ,当时按 7度设防考虑 ,存在着许多不符合抗震要求的问题 ,一些设施也明显不能满足现代使用功能要求。北京火车站抗震加固与改造设计项目组 ,运用多种先进的加固手段 ,在保持原建筑外貌不变的前提下 ,实现了抗震能力和改善使用功能的协调 ,取得了大型公共建筑加固改造的新经验     

粘土作为高放废物处置回填材料的可行性研究

本文以西北粘土为对象,对其压实行为、热传导、膨胀特性,以及吸附和渗透性能进行了初步研究,借以探讨西北粘土在高放废物处置中用作回填材料的可行性。试验表明,以西北粘土为基材,经过适当的热改性和吸附改性,在初始含水量约为9%,于70MPa 下成型,用作高放废物处置中的回填材料是可行的。     

反井钻及其在我国水电工程的应用

本文介绍了反井钻这一新型的竖井和斜井开挖施工设备，以及该设备在国内水电工程中的应用。实践证明，在适当的地质地形条件下，反井钻比人工正井法、吊罐、阿里马克爬罐法都具有明显的优越性，值得在国内其它水电工程中推广应用。     

多功能超高速计数器

脉冲信号计数是最简单的数据获取工作和最基本的测量方法。在许许多多高科技领域中,对计数器(Counter)计数分辩率提出很高要求。当前,核物理上应用的计数器都有计数率较高(最高为200MHz),结构复杂,价格昂贵的缺点。本文报导我们最新研制的一种计数率为500MHz的超高速计数器,后级采用Intersil公司生产的通用计数器电路ICM7216B,只需外接少量元件就可构成最简单多功能超高速计数系统。     

Synthesis, characteristics and oxygen-sensitive properties of SrMgxTi 1 − xO3 nanocrystals

SrMg_xTi_{1 - x}O₃ nanocrystals (x = 0.1–0.6) were synthesized by the stearic acid gel method. Powder samples were characterized by X-ray diffraction and X-ray photoelectron (XP) spectroscopy. The results showed that the lattice parameter a and the O 1s XP spectrum changed not only with the Mg content x but also with the grain size d of the samples. The conductivity of a thick film specimen fabricated on an aluminium oxide wafer was investigated in a nitrogen—oxygen atmosphere.     

循环流液相等电聚焦方法及应用研究

利用循环流液相等电聚焦技术，对Ｈｂ、Ｃｙｔ．Ｃ和ＢＳＡ混合物进行分离，对ＲＮａｓｅＡ粗制品进行精制。该方法上样量大，活性回收好。对聚焦过程中扩散、对流和电渗的影响进行了讨论。