Threaded Joints of Slewing Bearings

A method is proposed for the analysis of slewing bearings.     

Damping Steels for Sheet Stacker Components During Sheet Rolling

Metallurgist - Steels alloyed with chromium are used for the first time for manufacturing sheet stacker components. Steel with a high chromium content (45X), exhibiting good damping properties,...     

Mathematical modelling of perorally induced immunological tolerance

A mathematical model of the mechanism of development of orally induced immunologic tolerance has been suggested. The model presents a system of differential non-linear equations, and it is realized as a program in FORTRAN. The model describes primary and secondary immune responses, reflects the main features of the immune system response to antigen intake with food. The immune system model response to varying doses and frequency of the antigen intake with food has been studied. It has been established that repeated administration of small doses of the food antigen leads to a deeper tolerance due to lower stimulation of the immune system. The existence of optimal tolerogenic doses of the food antigen has been proved. Qualitative changes in the immune system response to the food antigen have been recorded in case of increased permeability of the intestinal wall.     

复杂环境下砖砌烟囱的爆破拆除

本文介绍了采用定向爆破拆除一座砖砌烟囱的施工设计方法,包括爆破方案选择、爆破切口设计和爆破安全验算等内容,对类似工程有一定的参考意义。     

基于激光多普勒技术的微悬臂梁机械特性的测量

介绍了一种微悬臂梁离面运动测试系统。结合显微激光多普勒技术,分析了用于间接测量微悬臂梁机械特性的方法,采用虚拟仪器技术建立控制系统,编辑器件激励和数据采集、处理软件,实现了对微悬臂梁的动态特性和杨氏模量、弹性系数等机械特性的测量。最后利用该测试系统对矩形、三角形微悬臂梁杨氏模量进行了实验研究,并计算了两种微悬臂梁的弹性系数。经实验证明,用该方法测量悬臂梁机械特性得到的弹性系数和杨氏模量误差小于7．5％。     

Mathematical modelling of two-phase flow in a vertical well considering paraffin deposits and external heat exchange

Processes, occurring during exploration of gas-oil wells in frozen rock are simulated. A system of differential equations, describing hydro and thermal dynamics of an ascending two-phase flow of a hydrocarbon system in a vertical channel taking into account phase transitions and structure of a flow is developed. Kinetics of paraffin deposits on internal walls of an elevating column of a well are considered. The effect of the heat exchange of a well within frozen rock is developed using differential equations that describe the evolution of the radius of thermal influence of the well and the radius of the melting zone. We conclude with numerical research of some preventive ways of dealing with paraffin deposits.     

Effect of ZnO layer thickness upon optoelectrical properties of NiO/ ZnO heterojunction prepared at room temperature

In this work, p-NiO/n-ZnO heterostructures were successfully prepared at room temperature using RF sputtering technique. The influence of ZnO layer thickness on the performance of the heterojunction was investigated. The deposited ZnO layers have a hexagonal Wurtzite structure with preferable growth orientations along (002) and (103) for thinner films. Increasing the thickness results in more crystallographic orientation randomness. The current–voltage measurements of the realized heterojunctions showed a clear rectifying behavior. The measured ideality factor varies from 2.5 to 1.6 according to the thickness of ZnO layer. The series resistance of the device is enlarged with increasing ZnO thickness. The deduced parameters from the I–V characteristics suggest that 200 nm is the optimal thickness of the ZnO layer according to our experimental conditions. We attribute the relatively better performance of this thickness to achieving reasonable compensation between serial resistance and ideality factor. The best heterojunction was tested and successfully used as a UV detector.