大型齿轮减速器的跑合

概述大型齿轮减速器齿轮跑合的目的和作用 ,着重研究跑合的过程及机理 ,分析影响跑合的主要因素 ,提出跑合的控制方法。     

双圆弧齿轮跑合的计算机仿真

建立了双圆弧齿轮跑合仿真的数学模型。该模型可以描述不同工况的圆弧齿轮跑合过程，得到双圆弧齿轮的理想跑合规范。分析了理想啮合状态和有中心距误差情况下双圆弧齿轮的跑合磨损规律，得到了跑合前后双圆弧齿轮接触区形状以及跑合磨损量变化曲线，计算结余与试验结果非常吻合。     

齿轮电火花跑合工艺

我公司为解决减速机跑合问题,引进DZ42型四闸流管双回路齿轮电火花跑合电源,该电火花跑合电源主要用于齿轮减速器跑合工艺,代替金刚砂研齿、空载跑合、人工刮齿、砂轮修磨等老工艺方法,减轻了劳动强度,提高了工效。     

跑合脂在钢—钢蜗杆传动中的应用

本文提出了一种新的跑合方法,利用新研制的跑合脂在极压条件下的腐蚀作用,通过化学抛光,降低表面粗糙度。这种跑合脂在钢一钢蜗杆减速机的实验中表明,跑合后的蜗轮蜗杆齿面精度可提高近三个等级。逼过对这种跑合脂作用机理的分析和跑合工艺方法的研究表明,本文提出的跑合方法对钢—钢接触高副传动具有重要意义。     

MoS_2固体润滑轴承跑合技术实践

介绍了航天用MoS_2固体润滑轴承润滑膜的结构和磨损机理,分析了跑合对该类轴承应用的重要性以及对润滑膜形貌和性能的影响。结合固体润滑轴承的跑合实践,总结并剖析了MoS_2固体润滑轴承跑合过程中常见的问题及解决措施。采用变载荷跑合,用绸布擦拭清洗沟道,合理设定跑合参数,通过跑合带宽度均匀性评估跑合效果等能够有效改善固体润滑膜的润滑效果。     

极压剂的含量对化学跑合效果的研究

采用BJ58A试验机考察了多烷基苄硫化物和氯化石蜡极压抗磨添加剂在铝基脂中对跑合性能的影响,探讨了多烷基苄硫化物和氯化石蜡极压抗磨添加剂的协同跑合性能;详细记录了跑合后试件的磨损量的变化,用表面轮廓仪观察了各种条件下的表面形貌。试验结果表明,极压添加剂的含量对跑合过程影响很大;选用活性强的极压添加剂来配制跑合剂,可以显著提高跑合速度,降低表面粗糙度,缩短跑合时间。     

圆弧齿轮跑合分析

从润滑、磨损和接触力学3方面对圆弧齿轮的跑合机理进行探讨,推导了跑合后油膜厚度计算公式,分析了不同齿面的跑合磨损量,确定了齿面法向磨损量的影响因素,最后指出圆弧齿轮的初始接触区对跑合有重要影响。     

CRH2型动车组齿轮箱跑合试验工艺研究

本文对CRH2型动车组齿轮箱跑合试验流程进行了介绍，同时根据动车组检修规程的要求，对齿轮箱跑合试验的试验标准及作业方法进行了说明。本文重点对齿轮箱的跑合试验工艺进行了分析，制定了合理的工艺流程，为CRH2型动车组齿轮箱的跑合试验作业提供参考。     

齿轮跑合的磨损机制研究

通过齿轮副跑合的模拟试验,得出齿轮副在跑合过程中磨损形式的转化规律。     

基于PLC和伺服电机的某星载滑环跑合台控制系统设计

滑环是卫星太阳电池阵驱动机构中的关键部件,为保证某星载滑环长时间工作稳定性,需要通过跑合台对滑环进行仿真跑合试验。已有跑合台工作方式不灵活、无法自动报警停机,亟需研制一种新型星载滑环跑合台。利用FX2N作为中央控制处理器集中控制整个系统的启动、运行,配合使用低速、高精度、低成本的交流伺服电机,完成跑合台控制系统设计。运用组态软件INSPEC设计监控系统,显示实时参数,存储跑合数据,实现故障自动停机。经现场运行,系统工作稳定可靠,满足设计要求。文中对该控制系统的硬件组成、系统功能、实时监控的实现均做了具体分析。     

Mice embryology: A microscopic overview

In this work, we studied the embryology of mice of 12, 14, and 18 days of gestation by gross observation, light microscopy, and scanning electron microscopy. Grossly, the embryos of 12 days were observed in C‐shaped region of the brain, eye pigmentation of the retina, first, second, and third pharyngeal arches gill pit nasal region on the fourth ventricle brain, cervical curvature, heart, liver, limb bud thoracic, spinal cord, tail, umbilical cord, and place of the mesonephric ridge. Microscopically, the liver, cardiovascular system and spinal cord were observed. In the embryo of 14 days, we observed structures that make up the liver and heart. At 18 days of gestation fetuses, it was noted the presence of eyes, mouth, and nose in the cephalic region, chest and pelvic region with the presence of well‐developed limbs, umbilical cord, and placenta. Scanning electron microscopy in 18 days of gestation fetuses evidenced head, eyes closed eyelids, nose, vibrissae, forelimb, heart, lung, kidney, liver, small bowel, diaphragm, and part of the spine. The results obtained in this work describe the internal and external morphology of mice, provided by an integration of techniques and review of the morphological knowledge of the embryonic development of this species, as this animal is of great importance to scientific studies. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

The actuality and progress of whole sky infrared cloud remote sensing techniques

Clouds are crucial regulators of both weather and climate. Properties such as the amount,type,height,distribution and movement of them have an impact on the earth's radiation budget and the hydrological cycle,thus cloud observation is very important. The disadvantages of zenith pointing measuring instruments and whole sky visible imagers limit the application of them.A summary of the actuality and application of ground-based whole sky infrared cloud measuring instruments and analyses of the techniques of radiometric calibrations,removal of atmospheric emission and calculation of cloud cover,amount,type are conducted to promote the automatically observation of the whole sky. Fully considering whole sky infrared cloud sounding theories,techniques and applications,there are still a lot of studies on improving the properties of instruments,enhancing the techniques of cloud base height measurements and establishing instrumental cloud classification criterion before actual operations.     

Estimation of surface area and length with the orientator

The orientator is a new technique for the estimation of length and surface density and other stereological parameters using isotropic sections. It is an unbiased, design-based approach to the quantitative study of anisotropic structures such as muscle, myocardium, bone and cartilage. A simple method for the practical generation of such isotropic planes in biological specimens is described. No special technical equipment is necessary. Knowledge of an axis of anisotropy can be exploited to optimize the efficiency. To randomize directions in space, points are selected with uniform probability in a square using various combinations of simple random, stratified random, and systematic random sampling. The point patterns thus produced are mapped onto the surface of a hemisphere. The mapped points define directions of sectional planes in space. The mapping algorithm ensures that these planes arc isotropic, hence unbiased estimates of surface and length density can be obtained via the classical stereological formulae. Various implementations of the orientator are outlined: the prototype version, the orientator-gencrated ortrip, two systematic versions, and the smooth version. Orientator sections can be generated without difficulty in large specimens; we investigated human skeletal muscle, myocardium, placenta, and gut tissue. Slight practical modifications extend the applicability of the method to smaller organs like rat hearts. At the ultrastructural level, a correction procedure for the loss of anisotropic mitochondrial membranes due to oblique orientation relative to the electron beam is suggested. Other potential applications of the orientator in anisotropic structures include the estimation of individual particle surface area with isotropic nucleators, the determination of the connectivity of branching networks with isotropic disectors, and generation of isotropic sections for second-order stereology (three-dimensional pattern analysis).     

Diverse roles for the Eph family of receptor tyrosine kinases in carcinogenesis

The Eph family of receptor tyrosine kinases and their cell-presented ligands, the ephrins, are frequently overexpressed in a wide variety of cancers, including breast, small-cell lung and gastrointestinal cancers, melanomas, and neuroblastomas. In particular, one Eph family member, EphA2, is overexpressed in many cancers, including 40% of breast cancers. EphA2 can also transform breast epithelial cells in vitro to display properties commonly associated with the development of metastasis. Remarkably, the oncogenic properties of EphA2 contravene traditional dogma with regard to the oncogenic properties of a growth factor and its receptor tyrosine kinase: while stimulation of EphA2 by its ligand (ephrin-A1) results in EphA2 autophosphorylation, the stimulation reverses the oncogenic transformation. As will be discussed in this review, the apparent dependence of oncogenicity on the dephosphorylated state of EphA2 most probably reflects the unique nature of Eph signaling. In particular, oncogenecity may depend on the capacity of unactivated EphA2 to interact with a variety of signaling molecules. As well as acting in oncogenic transformation, a growing body of evidence supports the importance of the concerted actions of ephrins and Eph molecules in tumor angiogenesis. Genetic studies, using targeted mutagenesis in mice, reveal that ephrin-B1, ephrin-B2, and EphB4 are essential for the normal morphogenesis of the embryonic vasculature into a sophisticated network of arteries, veins, and capillaries. Initial studies indicate that these molecules are also angiogenic in tumors, and as such represent important new targets for the development of chemotherapeutic treatments.     

XPN-FMS: A CAD tool for FMS modeling, analysis, animation, and simulation using Petri nets and X window

We propose a CAD tool, XPN-FMS, which is primarily based on a unique Petri net (PN) synthesis method, called the knitting technique, developed by the authors. Petri net theory has been applied to specification, validation, performance analysis, control code generation, and simulation for manufacturing systems. The analysis of flexible manufacturing systems (FMSs) based on PNs suffers from the complexity problem of reachability analysis (Peterson, 1981). CAD tools are urgently needed. There is no existing CAD tool for FMSs as comprehensive as XPN-FMS, in the sense that the latter integrates the functions of drawing, analysis, reduction (Chao and Wang, 1992; Murata and Koh, 1980), synthesis, property queries, and animation of FMS operations in one software package. Using the X window graphical interface and animation, XPN-FMS makes the modeling and analysis of an FMS visualizable and easy to understand and manipulate. It lets a user draw the factory layout of an FMS on the screen of a monitor using the supplied tools. A corresponding PN model can also be drawn on the monitor screen. XPN-FMS can animate and simulate the overall operating process of the FMS. It is useful for FMS specification, validation, and exploration of different design alternatives, status monitoring, and control. Using XPN-FMS with various inputs and comparing the resulting outputs, the user can determine how to improve efficiency, reduce cost, and pinpoint bottlenecks. For the PN models of FMSs that are decision free, we extend the theory and algorithm of a unique matrix-based method (Chao and Wang, 1993b) to search for subcritical loops (including types A and B) and to support scheduling and dealing with transition periods. XPN-FMS implements this extended method to find the minimum cycle time, critical loop, subcritical loops, next critical loop, and scheduling ranges to avoid the transient period for static scheduling. This is implemented in XPN-FMS for the input sequence control.This project is partially funded by NJIT's Separately Budgeted Research Program. Portions of this article were presented in Chao, Chen, Wang, and Zhou (1992),Proceedings of the 1992 IEEE International Conference on Systems, Man, and Cybernetics, Chicago, Illinois, October 1992. The former name of the first author, which has appeared in some of his earlier publications, was Yuh Yaw.     

Lubricant components from vegetable oils of indian origin

A number of transesterified and alkarylated derivatives have been synthesised from available vegetable oils of Indian origin. The viscosity, viscosity index, freezing points, load-carrying characteristics, friction coefficient, and thermo-oxidative stability of these derivatives as compared to highly refined hydrorefined hydrocarbon oils have been studied. It has been found that several esters of fatty acids of these vegetable oils have a high natural viscosity index, low pour points, and high thermooxidative stability, and can meet the requirements as base fluid components for energy-efficient, eco-friendly, long-drain interval, multigrade oils. These oils have markedly lower viscosities at 40°C, higher load-carrying characteristics, and lower friction coefficients than the base fluids of currently marketed multigrade oils. A 50% blend with hydrorefined hydrocarbon oils could prove highly viable. The above results clearly establish the potential for utilising these esters, either alone, or in combination with mineral oils, for formulating cost-effective high-performance, energy-efficient, and environmentally friendly lubricants. Performance characteristics of these oils as engine oils, automotive gear oils, and 2 stroke oil with conventional additives and with alternative additives are under investigation in comparison to the most advanced hydrocarbon based multigrade oil formulations of long-drain interval.     

Research on the calibration method of precipitation micro- physical characteristics sensor

In order to diminish the effect of the ambient light and CCD pixel non-uniformity to the Precipitation Micro-physical Characteristics Sensor,a modified calibration scheme was designed and calibration experiments in sunny,cloudy,night,different location of sample space were carried out. Firstly,the characteristics of particle images which affected by ambient light and different location of sample space were analyzed. Secondly,the relevance betw een particle image features and parameters of image processing were discussed. Finally,the parameter setting scheme were determined,the radium of median filtering algorithm is 3 pixels,the defocusing radius of point spread function( PSF) is 7 pixels,the radium of erosion is 3 pixels,and the binary threshold is obtained from the Area-thresh relationship. The results show that the new scheme could deal with the image calibration well,the average errors of equivolumetric diameter was 0. 041 mm with standard deviation of 0. 115 mm,and the average errors of the axis ratio was 0. 011 with standard deviation of 0. 085. The new scheme works well in the field observation too,the observed axis ratio is consistent with the empirical relationship that proposed by Beard. The relative error of accumulation precipitation is-3. 06% after calibration,w hich is improved 1. 94% low er than the initial one without calibration.     

机床夹具使用寿命的影响及对策

对机床夹具使用寿命的影响因素进行分析,特别对延长使用寿命的对策作了探讨,具体措施有:合理设计夹具结构;合理调整夹具相关尺寸;合理制定制造精度;合理选择材料;提高夹具易损件的表面硬度;有效润滑;以及正确地进行夹具的安装、调整、使用和维修等.     

Preparation of magnesium borate succinimide and its characteristics as a lubricating oil additive

Succinimide has for a long time been widely used for ashless dispersants in engine lubricating oils. However, this kind of dis‐persant does not have particularly good antioxidant, antifriction, antiwear or acid neutralisation properties. In this paper, a method is suggested for modifying succinimide so as to obtain improved antioxidant, acid neutralisation, antifriction, and antiwear properties. Magnesium borate cannot be dissolved in mineral lubricating oil. In the presence of succinimide, however, it will exist in a lubricating oil in the form of a colloid or complex. Therefore, in the present work, magnesium oxide, boric acid, and water were mixed together with succinimide. In the reaction process, some of the magnesium borate formed in situ will be surrounded by succinimide, forming stable colloids; the remainder will react with the succinimide, forming well distributed complexes in the lubricating oil. The presence of water is very important for this process. At least four moles of water are needed for one mole of magnesium borate. The resulting material has been evaluated as a lubricating oil additive. The experiments have shown that this kind of material possesses good antioxidant, acid neutralisation, antifriction, and antiwear properties, apparently due to the introduction of magnesium borate. The introduction of the magnesium borate does not influence the good dispersant properties of the succinimide.     

Total vegetable oil greases

A grease has two major constituents, namely, a lubricant, that performs the function of lubrication; and a gellant, that provides a solid continuous phase, occludes the lubricant, and gives apparent physical structure to the grease. Generally, the gellant is 5–30% and the lubricant 65–90%, additives and fillers making up the rest. In conventional greases, the gellant is a vegetable oil soap, and the lubricant is a liquid oil of petroleum origin or is a synthetic. Such greases have limited biodegradability, because the major constituent, i.e., the lubricant, is normally not biodegradable. In total vegetable oil grease, both the gellant and the lubricant are derived from vegetable oils, giving a grease of potentially high eco‐compatibility. Esters, dibasic acid esters, and alkylated esters of vegetable oil are known to be high‐quality lubricants. These can be used with soap stocks prepared from vegetable oils to give a grease of total vegetable oil origin. The vegetable‐oil based lubricants and soaps are prepared separately and combined in appropriate proportions to give a grease of the required specifications. Alternatively, esterification and saponification can be carried out simultaneously to give a grease of the desired specifications, where an alkali will be the catalyst for esterification, and reactant for saponification. In this paper, the process parameters, and kinetics of these simultaneous reactions are discussed. The results of experimental evaluation of some of these greases are also presented.