珠江三角洲数控机床市场演绎“壮观”

在荔红稻熟，赛龙夺锦的端午时节，走进广东珠江三角洲地区名优荟萃的数控机床市场，琳琅满目，供求络绛，交易火热，生产旺威。无论是生产厂家推出的，经销商场陈列的，还是展览场所展示的数控机床，技术精益求精，外形色彩缤纷，功能不断优化，价格竞争激烈。国内外厂家纷至沓来，各显神通，抢滩登场，新产品上市象赶集，以争占市场的“话语权”。     

车加工薄壁管内孔的专用夹具

在车加工薄壁管内孔时，由于管壁较薄，刚度差，采用三爪自动定心卡盘装夹时，若夹持较紧，则变形大，若较松，则不能夹牢，即使松紧适当，也难以克服内孔圆度的误差，尤其是加工软材料，无法达到技术要求。在生产如图１所示的零件时，按传统方法，用三爪卡盘装夹，圆度很难达到要求，废品率达９０％以上，采用如图２所示的车加工薄壁管内孔的专用夹具后，废品率不到１％。车加工时，利用三爪卡盘夹紧管套，将长度已加工好的工件放入管套内，然后把旋压盖旋入管套将工件进行轴向压紧，再车内圆进行正常加工，完工后退出旋压盖，将工件换头，…     

ICP—AES法测定镍基合金中合金元素含量

本文采用电感耦合等离子体发射光谱（简称ＩＣＰ）对镍基合金中锰，铬，铜，钴，钛，钼，铁，铌，钽的分析方法进行了试验，研究了载气流量，输入功率，观测高度等对测量镍基合金中各元素的影响，并对镍基合金试样进行了准确分析，本方法灵敏度高，操作简便，快速，适用于日常分析检测工作。     

一种超声检测机械手的设计

借助于超声检测技术，机器人技术，数字控制技术，计算机技术等，研制了一种用于超声检测机械手，该机械手由机械系统，伺服系统，检测系统等组成，通过PC机控制，能够实现自动控制并实时获取坐标信息，有利于缺陷的定位，定量和定性分析，其结构简单，性能价格比高，不仅能够用于超声检测，而且也可以用于其他场合，具有广泛的适应性。     

西红柿中糖酸等含量的非破坏分析

本文探讨了用近红外光谱法非破坏检测西红柿中糖，酸等上种成分的可行性，采用二阶导数来处理光学数据，分别筛选出８３２ｎｍ，９１６ｎｍ，１０００ｎｍ，１００４ｎｍ代表西红柿中可溶性固形物，有机酸，维生素Ｃ，还原糖的第一特征波长，经多元线性回归分析，与国际法相比，其相关系数分别为０．９９４，０．９８３，０．９９０．０．９８７。对４０个预测样品的检验误差为０．０５７，０．００７，０．４４０，０．０３７，结果     

“九五”湖北省机械产业技术发展对策探讨

提出“九五”期间湖北省机械产业技术发展的对策设想，通过技术创新，造就一批以创新产品为龙头，以资产为纽带的技术开发能力强，在国内外有较竞争力知名度的企业和企业集团，集中开发汽车（轿车，农用车，轻型车），大型发电，输变电设备，通用机械，机电一体化设备，环保设备。     

一种新颖手摇液压升降车的研制

为了解决某产品集装箱空运时装，卸机问题，研制了剪叉式手摇液压升降车。该车采用剪叉式机械结构，手摇泵液压驱动，结构简单，设计新颖，升降平稳，操作方便，载重量大，升降范围宽，外形小，质量轻，运行方便，转弯灵活，是一种理想实用的空运地面设备。     

二阶变参数流通伺服系统的滑模控制器参数选择与性能分析

采用本文介绍的方法，由于滑模存在的边界曲线Г＾＋１，Г＾－１，Г＾＋２，Г＾－２，Г＾＋２和Г＾－３有明确数学表达式，而只要选择σ１，σ２，σ３在边界曲线所包围的区域内，滑模方式便存在，故开关线σ１，σ２，σ３，的选择避免了盲目性；又由于滑模控制器的参数αｉ，βｉ，γｉ，ρｉ和Ｃｉ的选择也有明确的数学表达式。     

数控刀具管理系统的设计原理与方法

在数控机床的使用中，数控刀具的管理无疑是影响其效率发挥的重要因素之一，亟待开发适合我国现阶段数控制造系统模式的刀具管理系统。本文介绍的刀具管理模式和方法是指数控刀具、辅具的供给，库存，刀具与辅具的选配，预调，分派，传格，上线，下线以及其后的拆卸，回库，检测和修磨等一系列的管理方法。为进行这些处理，刀具管理应具有一些硬件，诸如刀库，预调仪，管理计算机．刀具传输装置等；同时，还有管理刀具，辅具信息的编码系统，数据库及其管理软件。作为具体的实例，本文以具有典型代表意义的四川自贡长征机床厂数控制造车间刀…     

高分子材料的摩擦学特性及其应用

大多数高分子材料，特别是聚四氟乙烯，尼龙，聚甲醛，超高分子量聚乙烯等工程塑料，具有优良的减摩，耐磨，自润滑性能，可以用作轴承，导轨，齿轮，磨耗板等。本文阐述了高分子材料的磨擦学特性，并列举了一些应用。     

磁流变液密封机制及结构设计

根据磁性液体的磁流变效应,推导出磁性液体密封压力的计算公式,通过测试磁性液体的屈服应力,验证了该公式。并将磁性液体密封结构用于磁流变液的密封,实验表明磁流变液具有较好的静密封性能。     

机器油液诊断与预报工程的可视化

概述了机器油液诊断与预报工程的范畴、目的以及技术现状和发展趋势．基于可视化概念分析了机器油液诊断与预报工程可视化的主要方面，包括机器油液状态可视化及其层次性．机器状态和油液状态参数，机器油液诊断与预报工程的虚拟可视化和真实可视化模式，以及获取机器油液状态可视化参数的基本仪器配置方案。     

Thermal Shaft Effects on Load-Carrying Capacity of a Fully Coupled,Variable-Properties Cryogenic Journal Bearing

The purpose of this work was to perform a rather complete analysis for a cryogenic (oxygen) journal bearing. The Reynolds equation required coupling and simultaneous solution with the fluid energy equation. To correctly account for the changes in the fluid viscosity, the fluid energy equation was coupled with the shaft and bearing heat conduction energy equations. The effects of pressure and temperature on the density, viscosity, and load-carrying capacity were further discussed as analysis parameters, with respect to relative eccentricity and the angular velocity. The isothermal fluid case and the adiabatic fluid case represented the limiting boundaries. The discussion was further extrapolated to study the Sommerfeld number dependency on the fluid Nusselt number and its consequence on possible total loss of load-carrying capacity and/or seizure (catastrophic failure). Finally, an attempt was made to discuss the change in entropy in the bearing during one given cycle as a function of the fluid pressure and temperature changes.     

Modeling and simulation of useful fluid flow rate in grinding

This research established a mathematical model of the useful grinding fluid flow rate of a rough grinding wheel. The abrasive distribution matrix of the grinding wheel surface topography was programmed on the MATLAB software platform to obtain the grinding wheel porosity φ at different particle sizes. The grinding fluid flow field was simulated and studied by using the volume of fluid multiphase flow model of FLUENT. Results showed that given a certain circular velocity of the grinding wheel, a larger grinding fluid jet velocity resulted in greater useful grinding fluid flow. When the grinding fluid jet velocity was set, the useful grinding fluid flow increased with increasing circular velocity of the grinding wheel. With the increasing velocity of the grinding wheel, as affected by the airbond layer, the increasing rate of the useful grinding fluid flow decreased, and the flow likewise showed a tendency to decrease. With a certain grinding fluid jet velocity, the useful flow rate of the grinding fluid was positively proportional to the useful flow. When the grinding fluid jet velocity changed and grinding wheel velocity was set, the grinding fluid jet velocity increased as the useful flow rate decreased. When the grinding fluid jet velocity was equivalent to the grinding wheel velocity, the useful flow rate of the grinding fluid was positively proportional to the useful flow. When the minimum clearance of grinding zone h increased, the useful grinding fluid flow and useful flow rate likewise increased. When the grinding fluid jet velocity was equivalent to the grinding wheel velocity, a larger nozzle gap width increased the flow supply for the grinding fluid and the useful grinding fluid flow. However, the increase in the useful flow rate of the grinding fluid was significantly smaller than that of the nozzle flow. This condition decreased the useful flow rate of the grinding fluid.     

Influence of cutting fluids on surface finish of holes drilled into aluminium 390

The primary objective of this research was to compare the surface finish resulting when using a semi-synthetic cutting fluid to that of a premium soluble oil. The secondary objective was to determine the effects of drill diameter, cutting speed, and fluid concentration on surface finish. The surface measurements were made on the walls of 6.350 and 9.525 mm lind holes drilled 25.4 mm into aluminium 390. Each cutting fluid was introduced using a flood application. Additional factors in the experimental design for each cutting fluid included two levels of cutting speed and two levels of fluid concentration. Variations in drill diameter, cutting speed, and the interaction between these factors were significant with respect to surface finish for both the semi-synthetic fluid and the soluble oil. Fluid concentration for the semi-synthetic fluid also had a significant effect on the surface finish. The surface finish produced while using the semi-synthetic fluid was approximately the same as that with the soluble oil.     

Properties of Dispersion of Multiwalled Carbon Nanotubes as Cutting Fluid

This article presents the results of experiments performed to evaluate properties of dispersion of multiwalled carbon nanotubes (MWCNT) in water with sodium dodecyl sulfate (SDS) as a dispersant. Different samples of varying concentrations of MWCNTs were prepared for the analysis and properties including thermal conductivity, pH value, viscosity, wettability, etc., were evaluated. These properties were compared with the properties of conventional cutting fluid, which was taken as a mix of water and mineral oil. It was found that the thermal conductivity of the MWCNT dispersion was higher than the conventional cutting fluid by about 42%. There was a decrease in contact angle by about 70%. Thus, dispersing MWCNTs in water with SDS increases the thermal conductivity and wettability of fluid. The pH value of fluid with 0.2 vol% MWCNTs was found to be 8.4. It thus reduced the corrosive nature of water. Nanoparticles of MWCNTs did not have much influence on the viscosity of the base fluid. Thus, the use of MWCNTs in water with SDS appeared to result in a better cutting fluid for machining than conventional cutting fluid.     

An empirical approach to modelling fluid dispensing for electronic packaging

Fluid dispensing is a popular process in semiconductor manufacturing industry which is commonly used in die-bonding as well as microchip encapsulation for electronic packaging. Modelling the fluid dispensing process is important to understand the process behaviour as well as determine optimum operating conditions of the process for a high-yield, low cost and robust operation. Previous studies of fluid dispensing mainly focus on the development of analytical models. However, an analytical model for fluid dispensing, which can provide accurate results, is very difficult to develop because of the complex behaviour of fluid dispensing and high degree of uncertainties of the process in a real world environment. In this project, an empirical approach to modelling fluid dispensing was attempted. Two common empirical modelling techniques, statistical regression and neural networks, were introduced to model fluid dispensing process for electronic packaging. Development of neural network based process models using genetic algorithm (GA) and Levenberg−Marquardt algorithm are presented. Validation tests were performed to evaluate the effectiveness of the developed process models from which a multiple regression model and a GA trained neural network with the architecture of 3-15-1 were identified to be the process models of the fluid dispensing respectively for the encapsulation weight and encapsulation thickness.     

磁流变液与电热形状记忆合金联合传动性能研究

针对磁流变液装置所产生的转矩偏小的问题,提出了一种磁流变液与电热形状记忆合金(SMA)联合传动的方法,并介绍了传动装置的工作原理。基于电热SMA弹簧力学特性,推导了温度与摩擦转矩的关系;通过有限元软件对装置进行了磁场分析,得到了环形磁流变液工作间隙磁场强度与磁流变液剪切屈服应力之间的关系,并计算得出磁流变液传递的转矩。实验结果表明：由8个SMA弹簧产生的摩擦转矩最大为1.798 N·m,励磁线圈的电流为1 A、匝数为380时,磁流变液传递的转矩为1.41 N·m。相较于单一的磁流变液传动装置产生的转矩,磁流变液与电热SMA联合传动产生的转矩为3.15 N·m,传动性能提高了1.2倍。     

Coriolis meter density errors induced by ambient air and fluid temperature differentials

Coriolis metering technology is widely applied throughout industry. In addition to the mass flow rate, a Coriolis meter can measure fluid density based on the resonant frequency of the flow tube vibration. There is currently increasing interest in utilising this density measurement capability as the primary process value in applications such as precision control for fluid property conditioning, and fluid contamination monitoring.However, within these applications, ambient temperature variation can be significant.This paper details research data obtained using NEL's ‘Very Low Flow’ single-phase facility. The rig was modified to include a programmable temperature enclosure in which a Coriolis meter was installed. Two commercial meter models from the same manufacturer were tested. Both meters showed fluid density errors when subjected to fluctuations in the surrounding ambient air temperature. The fluid properties of the test medium were confirmed to be stable using NEL's UKAS standard reference instrumentation.Previous temperature effects research for Coriolis meters have focussed on the process fluid temperature and there is little published data on the effects of ambient temperature.     

Magnetic-fluid microelectromechanical light modulator

1Introduction Duringthelastfewdecades,avarietyof techniquestoimplementmicroelectromechanical systems(MEMS)basedopticalmodulatorshas beenexplored[13].Themicromirrortechnologies arethemostprominentexamplesofthesuccess storiesintheopticalMEMSarea.Themi cromirrordeviceshavedemonstratedgreatper formanceparticularlyintheprojectiondisplay areas[23].Despitethegreatpotentialforcom mercialapplications,themicromirrordevices haveacleardrawbackintheflat paneldisplay(FPD)applications.IfanFPDisthebestf…