电梯导轨调扭机液压系统调长部分建模和动态分析

电梯导轨调扭机是根据生产的实际需要而研制的,用来矫正电梯导轨毛坯。在该设备中采用了机械、液压、电气技术,是机电一体化的自主研发的电梯导轨专用加工设备,填补了国内空白。电梯导轨调扭机液压系统为多缸控制回路,它简单实用,安全性能好。结合电气控制系统共同完成电梯导轨的调扭工作,自动控制水平较高。笔者对电梯导轨调扭机液压系统调长部分作了基于MATLAB的Simulink建模和动态分析,为进一步设计提供了理论依据。     

土壤的发射率随含水量变化规律的探讨

对常温地物的波谱测量是遥感技术的重要方面。土壤是地表最常见的地物之一,除裸露的外,它的特性对其上面的植物等有着重要的影响。本文着重研究土壤的发射率和其含水量的关系。典型土壤样品是来自黑龙江省的“三江平原”,有草甸土、泥炭土、棕壤和沙土。在实验室条件制备了各种土壤的不同含水量样品,用辐射方法测量了各样品的表面发射率。对测量结果进行分析处理得到土壤的发射率和表面含水量的关系:ε=a+b(ω-k)^1/3式中ε为发射率ω是绝对含水量,a、b、k 是由不同类型土壤确定的常数.     

山区铁路钢轨磨损情况调查与防治技术试验研究

介绍了对实际线路钢轨现状调查的结果:随着我国五次铁路提速,铁路的超负荷运行,加上路线等原因导致铁路钢轨磨损严重．通过制定相应的抗磨损措施并进行实践操作,在对比分析基础上,得出机车合理轮缘喷脂间距能有效减缓钢轨鱼鳞伤损的发生和发展,提高钢轨防断能力,在此基础上提出适合我国山区铁路的抗磨损方法和保养措施．结论对我国铁路钢轨的养护具有参考价值．     

当前企业文化建设与思想政治工作的几点思考

分析了新时期企业思想政治工作面临的新情况,探讨了企业文化与思想政治工作的统一性,提出将企业文化建设作为一种新载体,以弥补传统思想政治工作的不足。     

水电联动技术在转载降尘中的应用与改造

通过对煤炭运输转载过程中产尘规律的研究,设计改造一种新型适合转载点的喷雾降尘控制系统,实现水电联动功能,较好地控制了转载点粉尘的产生,保证了矿井煤炭的运输和生产。     

Measurements of the diameters of the great arteries and semi-lunar valves of chick and mouse embryos

The great arteries of embryos are small channels of a complex three-dimensional arrangement. Measurements of their diameters, as required for understanding cardiovascular morphogenesis and the genesis of malformations, cannot be performed in two-dimensional histological sections. We present and evaluate a quick and simple method for performing highly significant and objective measurements of the diameters of blood vessels in vertebrate embryos and used this method for providing statistics of the diameter of the semi-lunar valves and the lumina of the great arteries of early chick and mouse foetus. We employed the high-resolution episcopic microscopy technique for generating volume data and three-dimensional computer models of the arterial trees of 30 chick embryos (Hamburger Hamilton stage 34), 30 mouse embryos of the OF1 strain harvested on 14.5 dpc, 30 embryos of the OF1 strain harvested on 15.5 dpc and 28 mouse embryos of the PARKES strain harvested on 14.5 dpc. The three-dimensional models (voxel size 2 μm × 2 μm × 2 μm and 3 μm × 3 μm × 3 μm) were used for defining virtual resection planes perpendicular to the longitudinal axis of the blood vessels at comparable positions. In these planes, we measured the lumen areas and the lumen perimeters. We also calculated the lumen diameter and the true lumen area from the perimeter and present statistical analysis. Finally, we evaluate and discuss the reliability and reproducibility of our method and present all measurements in a form that minimizes the influence of specimen size variation, specimen processing and data generation methods.     

柱形杜瓦容器圆端板的结构设计与分析

杜瓦瓶是射电望远镜上接收机系统的前端。文中针对一种柱形杜瓦容器的结构特点，应用经典板壳力学理论，分析计算了在两种实验工况下．即大气压力单独作用、及大气压力与横向外力同时作用时，圆端板的结构尺寸。推导出了均布载荷及横向载荷共同作用下的中心开孔圆板挠度公式。并在ANSYS上，建立了模拟真实载荷条件下杜瓦容器的有限元模型．计算了变形场，逆向检验了结构的可靠性。     

有机化合物分子式的组合方式和分布规律的研究及其应用

多年的观察和研究初步证实，自然界有机人合物可能存在的合理分子式在种类和数量上是有限和可知的，对分子量１０００以下的式范围了符合实际的界定方法和计算式。据此已经人工书写或计算机打印出分子量１６－８００、只Ｃ、Ｈ、Ｏ、Ｎ分子式２０３４７０个，初步估算分子量到１０００时共有分子式４７４０００个。若以分子量为横坐标，分子式中的碳原子数为纵坐标作图，除个别外，这些分子式均分布在坐系的一个三角形区域内，因而称     

Calculation of the geometric position and the sizes of the static friction and sliding friction zones at the point of contact between an elastic wheel and a firm surface

A method for mathematically determining the geometric position and sizes of static friction and sliding friction zones at the point of contact between an elastic wheel and a firm support surface has been proposed. Schemes for the initiation and growth of the sliding friction zone at the point of contact upon an increase in the braking torque have been developed. The technique is based on the results of theoretical and experimental research.     

Mapping of the morphological and the material characteristics on the glenoid and estimation of predominant loading condition on the glenoid through the mapping

The aim of this study was to predict and map the regional distribution of the trabecular architecture and the material properties of the glenoid and to estimate the predominant loading condition on the glenoid through the mapping. The morphological and material characteristics of the glenoid were investigated by analyzing digitized trabecular bone images obtained from twelve cadaver scapula specimens. The morphological and material characteristics computed from the cadaver specimens show that the predominant loading on the glenoid generally occurs during shoulder movement, which produces forces directed toward the posterior aspect of the bare region. This study is innovative in its detailed mapping of the morphological and material characteristics of the glenoid and its pioneering approach used to estimate the loading pattern acting on the glenoid through the mapping. This paper was recommended for publication in revised form by Associate Editor Young Eun Kim Dohyung Lim received B.S. and M.S. degrees in Biomedical Engineering from Inje University, Kimhae, Korea, in 1998 and 2000, respectively. He then went on to receive his Ph.D. degree from School of Biomedical Engineering, Science, & Health Systems, Drexel University, Philadelphia, PA, USA, in 2004. Dr. Lim completed a postdoctoral fellowship in Department of Physical Therapy and Human Movement Science, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA and a Research Professor of Biomedical Engineering, Yonsei University, Wonju, Gangwon, Korea. Dr. Lim is currently a Senior Researcher at the Korea Institute of Industrial Technology in Cheonan, Chungnam, Korea. Han-Sung Kim received B.S. and M.S. degrees in Machine Design and Production Engineering from Hanyang University, Seoul, Korea, in 1989 and 1991, respectively. Dr. Kim received Ph.D. degree in Mechanical Engineering from University of Manchester Institute of Science and Technology, Manchester, UK, in 1999. Dr. Kim is currently an Associated Professor at the Biomedical Engineering at Yonsei University in Wonju, Korea. Jung-Sung Kim received B.S. and M.S. degrees in Biomedical Engineering from Inje University, Kimhae, Korea, in 1996 and 1998, respectively. He is currently in the doctor’s course in Department of Medical Engineering and BK 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea. Rami Seliktar has a BS and MS degree in Mechanical Engineering, from The Technion, IIT, and Ph.D. (BME) from Strathclyde University, Scotland. He has held academic appointments in several institutions worldwide: Strathclyde University (2yrs.); associate professor at the Technion (9yrs.); Texas A&M (on sabbatical leave from the Technion), and twenty seven years as professor of BME and ME at Drexel University in Philadelphia. Concurrently he founded and directed a Biomechanics laboratory at the Loewenstein Rehab. in Israel and consulted to governments, public agencies and industries. Prof. Seliktar has done research on limb prosthetics, human performance, orthopedic and occupational biomechanics, assistive technology for automomobil dynamics. His research has been funded by: The NSF, NIH, the RWJ Foundation, the Easter Seal Foundation, NIDRR, AIduPont, the United Cerebral Palsy and some hospitals. He has published numerous articles in scientific journals, book chapters and conference proceedings. At the present, Rami Seliktar is Professor and Vice Director of the School of Biomedical Engineering, Science and Health Systems of Drexel University. Sung-Jae Lee received B.S. and M.Eng. degrees in Mechanical Engineering from Cornell University, Ithaca, NY, USA, in 1984 and 1985, respectively. He re-ceived Ph.D. degree in Biomedical Engineering from University of Iowa, Iowa City, IA, USA, in 1993 Dr. Lee is currently a Professor at Department of Biomedical Engineering, Inje University, Gimhae, Gyongnam, Korea. He is currently serving as a board member for the Division for Health Care Technology Assessment of International Federation of Medical and Biological Engineering (IFMBE), a executive member of Korean Orthopedic Research Society, director of international relations for the Korean Society for Biomaterials and also for the Korean Society of Biomechanics.     

Analysis and Application of the Singularity Locus of the Stewart Platform

The direct use of the determinant of Jacobian matrix being equal to zero for the singularity analysis is generally difficult which is due to complexity of the Jacobian matrix of 6-DOF parallel manipulators,especially for Stewart platform.Recently,several scholars make their great contribution to the effective solution of this problem,but neither of them find the right answer.This paper gives a brief analysis of the kinematics of the Stewart platform and derives the Jacobian matrices of the system through the velocity equation.On the basis of the traditional classification of singularities,the second type of singularity is investigated.An assumption of any three of the six variables of the Stewart platform as constant is made,then the analytical expression of singularity locus equation of the second type singularity which contains another three pose variables is obtained.The singularity locus is represented in the three-dimensional space through the derived equation.The correctness and validity of the proposed method are verified through examples.Finally,the singularity analysis of an electric Stewart platform in its desired workspace and reachable workspace is implemented.Thus,one can easily identify whether singularity exists in a given workspace of a Stewart platform and determine whether the existed singularity can be avoided through the proposed method.The proposed method also provides theoretical principle for the design and application of the Stewart platform and has great significance for the trajectory planning and control.     

截齿的可转性和可靠性

分析了工程机械工作装置上截齿(锥形刀头)的可转性和可靠性,并论述了可靠性的影响因素以及提高可靠性的措施.理论和实践表明,截齿在截割工作中能够旋转,确保截齿旋转是提高可靠性的极为重要的因素之一.     

转盘大小及转速与料堆深度对掘进机装载效率的影响

针对影响掘进机装载机构装载效率的设计参数——转盘大小、转速、插入料堆深度等进行研究、优化,确定最佳设计参数,为掘进机装载机构效率的提高提供了一定的依据。     

浅释蜗轮蜗杆传动中齿形的影响与改善

指出在蜗轮蜗杆减速装置中,齿形是否准确,是影响蜗轮蜗杆传动质量的主要原因之一。文章先对蜗杆的齿形进行了分析,又指出如何提高蜗轮蜗杆齿形的准确性问题,其他是有效提高蜗轮蜗杆的传动效率、降低传动噪声和温升的重要手段。并针对ZA型蜗轮蜗杆齿形的加工工艺及齿形的成形加以分析和探讨,总结出了ZA型蜗轮蜗杆齿形传动中的问题,提出了改善的方案,即在ZA型蜗轮蜗杆传动中,采用磨削蜗杆的齿形,克服由于齿形不准所造成的不良影响,来改善传动质量,提高产品品质。     

一种模糊控制系统算法模型及查询表的设计

本文建立了一种双输入单输出控制系统的模糊控制的模型 ,设计了离线求模糊控制器的查询表的方法 ,实时控制过程可直接查询使用     

Image-based measurement of the dimensions and of the axis straightness of hot forgings

Non-contact measurement of shapes and dimensions is currently quite a common issue. A lot of systems with different speeds and accuracies are in the market. Measurement of high temperature objects is, however, a very special task which ensures a specific solution. This paper presents a measurement system composed of two high resolution single-lens reflex cameras and a software application, which is designed for the fast measurement of shapes and dimensions of rotationally symmetric forgings. The software computes the length, diameter, and straightness of the axis, based on a 3D model constructed from four boundary curves of the forging captured in two images. Experimental measurements have shown an error of up to 2% for the length measurement and 1% for the diameter measurement. Results are available in a few seconds. The proposed measurement approach based on boundary curves shows a great potential for practical use in forging plants.     

液压系统的振动与噪声分析

分析液压系统振动与噪音产生原因及危害性。提出减小和消除液压系统振动的措施,为液压系统的设计提供依据。     

Spatial Nonuniformity of the Sensitivity and the Errors of Induction Magnetometers

Errors arising in the process of studying the magnetic and resistive properties of materials with the use of pulsed induction magnetometers as a result of a local nonuniformity of the magnetometer sensitivity are considered. It is shown that significant nonuniformity leads to distorted current–voltage characteristics of conducting samples and to errors in determining the critical currents of superconductors, which are not eliminated by the standard calibration procedure of magnetometers. Various designs of pickup probes for magnetometers are analyzed from the point of view of the spatial uniformity of their sensitivity, and some recommendations are given for their improvement.     

海洋资源的开发利用和环境保护问题的探讨

我国是世界上人口最多的沿海国家，可持续发展必然越来越多地依赖海洋。近几十年来，由于对海洋资源的过度开发，大陆污染物入海、石油污染、突发性污染事件逐年增多。重开发利用而忽视环境保护，造成了沿岸区海洋环境质量逐年退化。因此，合理开发利用海洋资源和加强海洋环境保护尤为重要。本文对我国海洋资源的开发利用和环境保护问题进行初步的探讨。     

The Influence of the Silicone Carbide Content and Type on the Microstructure and the Flaw Level of Silica Ceramics

Comprehensive studies of the flaw level and some structural characteristics of a composite ceramic material based on Karakeche clay (Kyrgyzstan) are carried out for a range of thermoactivation regimes and impurity contents of silicone carbides of various types.