智能化外圆磨削主动测量仪的研究

作者以十六位单片机８０９８为核心开发了一种智能型外圆磨削主动测量仪。该仪器功能齐全、结构紧凑、调整方便,同时可方便地实现标准尺寸、下偏差及上偏差的输出,绝缘尺寸显示,相对尺寸显示,最终尺寸打印输出等,并可人为选择最终控制点在公差带中的位置。本文介绍该仪器的机械结构及电路原理。     

试验仪器户外专用可调节型遮光防晒装置的研制

研制了一种试验仪器户外专用可调节型遮光防晒装置,适用于绝大多数试验仪器操作面板及显示屏,该装置大小尺寸及高度均可调节,收纳方便、操作简单,能随时随地保护仪器不受阳光直接照射而发热损坏,延长仪器使用寿命,解决试验人员在强光下作业时阅读和记录显示屏上数据、图像困难的问题,节省人力、物力,提高安全生产水平与工作效率。     

关节轴承球面尺寸检测仪的误差修正方法

针对关节轴承球面尺寸检测仪专用于测量不同尺寸系列工件的特点,提出了关节轴承球面尺寸检测仪误差在线辨识与修正法。该方法通过在线测量系列工件和分析实测结果,可以准确地辨识并修正仪器系统误差,具有无须借助标准件、可低成本大幅度提高测量精度的优点。实验结果表明,使用该方法,仪器的测量值与高精度仪器测量值的偏差在10μm以内,最大测量误差由修正前的0.110mm减小到0.004mm,仪器测量精度明显提高,满足了企业提出的测量精度要求。     

轿车翼子板装配偏差建模与定位工艺优化

轿车翼子板装配质量对整车尺寸质量有很大影响。造成翼子板装配偏差的因素有:翼子板本身尺寸偏差、白车身尺寸偏差、装配工艺工装偏差。在实际生产中,通过对翼子板的定位优化来减小输入偏差对最终装配偏差的影响,是减小翼子板装配偏差、提高装配质量的首选途径。结合基于欧拉变换的空间零件偏差传递模型和MPS优化算法,建立了一套针对翼子板的建模与定位工艺优化方法。此方法在某自主品牌轿车生产中的应用取得了明显的效果,并且显示出比传统优化方法更高的效率。     

QXP——410型气动偏差指示调节仪

西安仪表厂从70年8月份开始,在短暂的几个月中研制成功了一台新型的气动调节仪表——QXP—410型气动偏差指示调节仪。该仪器的优点:①进一步小型化:正面尺寸为80×160毫米。②显示刻度清础、易于读数;有效刻度     

行业信息与动态

<正> 61W小型分光光度计由上海光学仪器厂研制的61W小型分光光度计,于最近通过了技术鉴定。该仪器主要用于农业、环保、地质、医疗、生物化学等部门作现场可见光范围内的吸收光谱分析,也可作为各院校分析专业的教学仪器。该仪器重量轻、体积小、操作方便,各项指标可满足常规可见吸收光谱分析、特别是满足现场及野外检测的需要。仪器采用微机数据处理,数字显示测量数据,具有较高的技术水平。     

SZd-923内径自动测量仪简介

SZd-923内径自动测量仪(样机见本期封面),用于轴承内圈内径的尺寸精度、形状误差等多项参数的自动分选.仪器由先进的意大利MARPOSS电子塞规、MIC-80B微型计算机及紧凑的机械机构组成,数据显示直观,可记录打印,测量方法符合国际标准(ISO标准).SZd-923 内径自动测量仪可测量单一内径偏差(?)d_s、单一平面平均内经偏差(?)d_(mp)、单一内径平面内的内径变动量V_(dp)、平均内径变动量V_(dmpo)     

虚公差及其在装配尺寸链中的应用

一、虚公差问题的提出及概念在公差中规定上偏差是尺寸允许的最大值,下偏差是尺寸允许的最小值,只要能保证尺寸不大于上偏差,同时又可保证尺寸不小于下偏差,那么这样的尺寸就可满足公差要求。根据上下偏差的大小,公差可分以下三种情况: 1.上偏差大于下偏差上差减下差即公差。根据定义,在上下偏差之间的任意一个尺寸都能满     

一种长短轴半径无级可调的椭圆规研制

目前的椭圆规结构复杂,长短轴长度调整及携带很不方便。基于一椭圆参数方程,研制了基于锥齿轮传动的长短轴半径无级可调的椭圆规。实际应用表明,该仪器结构简单,便于携带,操作方便,长短轴半径无级可调,可绘制不同尺寸的椭圆。     

AutoCAD环境下公差与配合自动标注二次开发

利用AutoCAD内嵌的AutoLISP语言设计开发了公差与配合标注应用程序。应用该程序 ,用户不必再通过查手册获得偏差数值 ,只需调用相应的命令并输入公差等级和基本偏差 ,即可标注出符合国标的各种尺寸公差或配合 ,并且可以方便地调整标注位置和修改参数 ,实现了尺寸公差的自动查询和公差及配合的快速自动标注     

Application of the leak before break (LBB) concept to a heat exchanger in a nuclear power plant

The leak before break (LBB) concept is difficult to apply to a structure with a thin tube that is immersed in a water environment. A heat exchanger in a nuclear power plant is such a structure. The present paper addresses an application of the LBB concept to a heat exchanger in a nuclear power plant. The minimum leaked coolant amount (approximately 37.9liters) containing the radioactive material which can activate the radiation detector device installed in near the heat exchanger is assumed. A postulated initial flaw size that can not grow to a critical flaw size within the time period to activate the radiation detector is justified. In this case, the radiation detector can activate the warning signal caused by coolant leakage from initially postulated flaws of the heat exchanger. The nuclear plant can safely shutdown when this occurs. Since the postulated initial flaw size can not grow to the critical flaw size, the structural integrity of the heat exchanger is not impeded. Particularly the informational scenario presented in this paper discusses an actual nuclear plant.     

Feasibility of the 248 nm Excimer laser in the laser structuring of fine circuit lines on printed circuit board

Excimer laser (KrF) is used as a new laser source to determine its feasibility in the laser structuring process. Compared with frequency-tripled Nd:YAG lasers, the Excimer laser can conveniently change the spot size of a laser beam to get a smaller sized circuit line/space by inserting a mask. Some frequently used laser parameters of the Excimer laser are discussed in this paper, such as laser energy, number of repetition, repetition rate, bite size and laser beam size. The differences between the Nd:YAG laser and the Excimer laser in laser structuring are also explored in this paper.     

Flow Field Characteristics for Parachute-projectile System

In the current research for parachute flow field nowadays,the size of parachutes in previous research are so large compared with their carriers that the effects of the carriers wake flow to parachute are always neglected.Different from such large parachutes,the parachute size in this paper is on the same magnitude with the carrier,thus,the carrier can obviously affect the parachute flow field.In this paper,flow field characteristics of small parachute for projectile decelerating are researched through two approaches,namely,computational fluid dynamics(CFD) simulation and wind tunnel tests.Three parachutes with various sizes are chosen for study.Firstly,the CFD simulation of flow field around these parachutes is carried out,and then the CFD simulation of parachute-projectile systems is executed.According to the simulation results,the phenomenon is observed that in the simulations of parachutes there are two vortex-rings at the wind shadow of parachutes,however,in the second simulations of parachute-projectile systems,two additional vortex-rings emerge inside the parachutes.Due to these two inner vortex-rings,the pressure inside parachutes decreases.As a result,the drag of parachute in simulation of parachute-projectile systems is about 20% smaller compared with the prior one.In order to verify the numerical results of CFD simulations,wind tunnel tests are employed.In terms of the data of the wind tunnel tests,the CFD simulation for flow field characteristics is reasonable and feasible.The results of both CFD simulation and wind tunnel tests demonstrated the influence of projectile wake flow to parachute drag can not be neglected if the parachute size is on the same magnitude with projectile.The influence to parachute drag from the ratio of projectile diameter to parachute diameter is also analyzed both in CFD simulations and wind tunnel tests.The approach combined CFD simulation and wind tunnel tests proposed can be used to guide the design of such parachute whose size is on the same magnitude with carrier.     

一种改进变步长LMS算法及其在系统辨识中的应用

在分析传统LMS算法及变步长LMS的基础上，本文提出了一种改进的变步长LMS算法并应用于系统辨识。新算法利用瞬时误差的四次方和遗忘因子共同来调整步长，进一步解决了收敛时间和稳态误差的矛盾。将新算法应用到系统辨识中时，与传统LMS算法和变步长LMS算法相比，仿真表明新算法有更快的收敛速率。     

PCS纳米颗粒粒度测试装置的研究

介绍了光子相关谱技术（PCS）测量纳米颗粒粒度的基本原理和PCS纳米测量装置的基本组成。因为纳米颗粒散射光所呈现的光谱是由颗粒粒径决定的，所以在纳米颗粒粒度测量中，单一角度测量只能观测到样品的部分情况。为了充分保证检测样品的真实表征及提高信噪比，文中提出了一个将步进电机和光纤联合应用于纳米颗粒粒度测量的设计方案。采用这个方案可以准确和方便地在不同角度上进行纳米颗粒粒度测量，而且有效地提高了信噪比和减小了装置的体积。     

Airborne particles detection and sizing at single particle level by a novel electrical current pulse sensor

A novel method for detecting and sizing airborne particles at single particle level is presented in this paper. When a particle hits a metal electrode which is grounded, electrostatic charges will be transferred between the particle and the electrode. As a result, an electrical current pulse will be generated in the measurement system. The number of the signal pulse represents the number of particles in the sample. To determine the effect of the particle size on the magnitude of the signal, the correlation between the magnitude of the signal and the size of particle was experimentally investigated. The results show that the magnitude of the measured signal is linearly proportional to the square of particle’s diameter. Such a correlation can be used to evaluate particle size from the measured signal. The airborne particle detection method presented in this paper can be used for counting and sizing airborne particles at single particle level.     

车用大功率两相Boost变换器耦合电感设计

大功率DC／DC变换器中交错并联技术被广泛使用。为了减小变换器的体积,将耦合电感引入大功率DC／DC变换器。首先介绍了相关理论,其次给出了耦合电感的设计步骤和公式,最后给出了有限元分析（finiteelementanalysis,FEA）仿真数据。将耦合电感和传统的单路分立电感进行了比较。仿真结果表明,给出的设计方法可行,可以大大减小变换器的体积。     

颗粒粒度在线测量的多对波长消光法

本文提出一种新的能实现颗粒粒度在线监测的多对波长消光法。理论分析及实验研究证实了这种方法的有效性。     

一种两坐标自动跟随式测量装置

论文就机械零件的相关尺寸的自动测量问题，提出了一种能实现两坐标自动跟随的测量装置。该装置由两层电动工作台和相应的传感器及测控电路组成，运动灵活，能快速跟随被测零件的尺寸变化，可广泛应用于工厂现场零件尺寸特别是相关尺寸的自动测量。该装置两个坐标方向的测量范围达到80mm(并可根据要求加长电动工作台的导轨，使测量范围进一步扩展），测量精度优于0．1％。当测量传感器离工件被测表面的距离为80mm时（最大），传感器跟踪到被测表面所需的时间为5秒。     

Modifications of stereological correction methods for precipitate parameters using transmission microscopy

Energy filtered transmission electron microscopy (EFTEM), dark field imaging and light microscopy are well established methods to evaluate size, volume fraction and number density of precipitates on different size scales. The stereological problems are well known and analogous for all methods. Many evaluation methods can be found in literature, each of them valid for special sample geometries or special size distributions. Despite this variety, serious errors can occur if the assumptions do not exactly represent the real situation. In this paper, available and newly developed correction methods are tested for evaluating these parameters for different precipitate size distributions in a sample of arbitrary topography. It is shown that the newly proposed methods produce significantly lower deviations and are more assessable regarding their systematic errors.