双踪示波器故障与维修实例

介绍CA8020型双踪示波器的常见故障现象及其产生的原因,给出了关键点测量数据和故障处理方法.     

基于三角形内心的数据拼接方法

分析了多视数据产生的原因及其不同的数据采集方法.并根据三基准点对齐的原理,采用合适的对齐方法,通过变换坐标从而达到数据时齐定位的目的.本文主要介绍了一种新的基于三角形内心的数据对齐方法.     

逆向工程中的多视数据对齐方法

在分析了多视数据产生的原因及其不同的数据采集方法,给出了解决多视数据对齐问题的方法。并根据三基准点对齐的原理,采用合适的对齐方法,通过变换坐标从而达到数据对齐定位的目的。本文介绍了目前在逆向工程中常用的几种数据对齐方法。     

三坐标测量机在反求工程中的研究

零件原型数字化就是通过特定的数字化测量工具来获得零件几何数据的过程。以某汽轮机叶片为基础,介绍了利用接触式三坐标测量机获取零件三维数据的步骤和方法,即通过装夹零件、标定测头测杆、工件坐标系的建立、测量打点、数据输出等步骤得到零件的几何三维数据。最后通过实例的操作,得到了叶片的点云数据,并分析了在手动打点过程中产生测量误差的原因及其改善措施。实例表明,确定合理的测量路径、建立合适的零件坐标系、确定合适的测点个数、均匀的测力及其操作经验,可以提高点云的精度。     

寻找用户潜在需求的新方法

为研究消费者的潜在需求,探讨了消费者的个性与产品特性之间的关系,建立了一种能够解释消费者基本行为原因的方法.对特性记录评估及诊断理论体系进行了阐述,以可视电话为例,分析了制造方、供应方和接受方3类用户之间的有效评估偏差及其产生的原因,得出了对可视电话感性评价的数据,验证了特性记录评估及诊断理论体系的有效性.     

单试样JR阻力曲线测试技术及其应用

介绍卸载柔度单试样法测定金属材料JR阻力曲线的基本原理和运用微机采集与处理数据的方法，详细分析裂纹负增长产生的原因，提出修正裂纹负增长的方法。测试了Mn-Ni-Mo高强度低合金钢及其焊接接头在－20℃的JR阻力曲线，试验结果表明卸载柔度单试样法测定JR阻力曲线有很高的精度。     

聚四氟乙烯(PTFE)制品的成型工艺及质量分析

本文介绍了聚四氟乙烯的成型工艺特性、成型方法及其模具设计的特点 ,对冷压烧结成型聚四氟乙烯制品的缺陷及其所产生的原因进行了分析 ,并提出处理方法     

车用电线接头温升超标原因分析和研究

通过对车用电线接头温升超标原因的分析和研究,系统地阐述了温升产生的原因及其影响因素,并明确了降低温升的方法。     

龙门起重机车轮啃轨故障分析与处理方法

通过分析龙门起重机车轮啃轨故障的危害性及其产生原因，并针对其主要原因提出了相应的改进措施与处理方法。     

鼓风机噪声的综合控制

鼓风机噪声产生的原因及其控制方法。     

Promoting contact strength of steel by rolling

The article deals with findings of experimental research on the running-in process of steel pieces with rollers that harden the contact strength. The hardening effectiveness of steel pieces physically simulates the bearing strain process, the physical and mechanical properties of the surface layer and its microstructure, and the diffusion of chemical elements by surface deformation using the chemical microanalyzer. The method and technology of running-in steel pieces of complex profile with the wedge roller and the device for the process implementation are developed. The findings are demonstrated for the adaptation of novel technology to production.     

螺杆制冷压缩机特性研究与优化设计

对螺杆制冷压缩机特性进行了全面、系统的研究,如工作过程p—V指示图的录取和研究、螺杆压缩机喷油可视化及其特性研究、螺杆压缩机排气压力脉动研究等,并利用试验和理论研究成果,对新系列螺杆制冷压缩机进行了理论型线、型线参数、啮合间隙、整机结构等多方面的优化设计。     

Externally Pressurized Spherical Gas Bearings

Spherical gas-lubricated bearings are of considerable interest in applications requiring a pivoting or rotating support with three degrees of freedom, for instance hi attitude control simulators of space vehicles. An analytical and experimental study of externally pressurized spherical gas bearings with orifice regulation is presented along with the experimental findings, which are in good agreement with the predictions of the viscous flow theory.     

Experimental analysis of factors influencing the cage slip in cylindrical roller bearing

This paper deals with the effect of operating parameters on cage slip in cylindrical roller bearing. A cylindrical roller bearing test rig is developed to measure the running speed of bearing elements at various operating conditions. The effect of operating parameters namely shaft speed, radial load, viscosity of lubricating oil, number of rollers, and bearing temperature on cage slip are experimentally obtained. The critical load and magnitude of cage slip for various operating conditions are obtained. The non-dimensional number is derived based on the operating parameters. The region where cage slip occurs is developed from the derived non-dimensional number and the experimental data. The temperature raise is experimentally obtained during slip condition and its effect on viscosity is included for calculations. The frictional forces are experimentally obtained and are compared with the theoretical findings. The significant effect of operating parameters on cage slip of cylindrical roller bearing is discussed based on the experimental findings.     

The influence of operating condition on acoustic emission (AE) generation during meshing of helical and spur gear

The application of high-frequency acoustic emission (AE) technology to condition monitoring of gears is still in its infancy. Understanding the influence of gear operating parameters on the generation of AE is essential in applying the AE technology to gear condition monitoring. This paper presents experimental findings on the influence of speed and load in generating AE for operating helical and spur gears. The experimental findings suggest that any percentage reduction in specific film thickness (λ), a direct consequence of a change in load condition, results in a nine- and four-fold percentage change in AE rms for the spur and helical gear sets, respectively. A numerical model representing changes in AE rms with variation in load and speed under near isothermal conditions for spur and helical gears was also established. In conclusion, it is postulated that the AE technology could offer a means of measuring in situ the effectiveness of a lubricant for operational spur and helical gears thereby establishing if the correct lubricating conditions are present to ensure optimal life usage.     

Investigations on the dust distribution characteristics of dry milling using inserts with various groove profiles

Dry milling experiments were conducted using five types of milling inserts with various groove profiles in order to investigate the dust distribution characteristics during the dry milling process. Firstly, the experimental scheme and testing system were designed. Secondly, dry milling experiments were carried out based upon orthogonal and single factor experimental methods, and the experimental data was collected. Next, the experimental results were analyzed, and the influence rule and action mechanism of insert geometrical parameters and milling factors on the dust concentration during the dry milling process were studied with the goal of targeting the profiles of inserts that produced less dust. MATLAB was used to interpolate and simulate the experimental data so as to further investigate the spatial distribution characteristics of dust particles around the machine tool. Finally, a dust capacity prediction model was established and validated. Our research findings will aid in improving the environmental quality of dry milling using inserts with complex groove profiles as well as provide theoretical and experimental basis for an in-depth study on the development technology of groove profiles.     

Theoretical and experimental study of vibrational behaviour of laminated stators of electrical machines

An accurate determination of the resonant frequencies and vibrational characteristics of a stator is essential in the design of quiet electrical machines. This paper presents both a fundamental theoretical and an experimental study of the vibrational behaviour of long and short laminated stators of electrical machines. The paper describes briefly the method of analysis, based on the three-dimensional theory of elasticity, for free vibrations of stators with encased construction. To prove the general validity of the analysis and to study the effect of windings, frame, and impregnation upon the resonant frequencies and vibrational behaviour of the stators of electrical machines, extensive experimental investigations were conducted on a number of stator models which include a solid model, long laminated, and short laminated models with and without windings, frame and impregnation. The paper compares the experimental and analytical results for some of these models which prove the general validity of the analysis. Finally, the paper also includes the important findings of these extensive investigations.     

Analysis of antiscoring properties of hydraulic oils

The paper discusses findings of the experimental study of the tribological characteristics of hydraulic oils HVLP-46, MGE-46d, MGE-46l, VO, ZF-46, and HLP-46. A technique is developed for studying the antiscoring properties of hydraulic oils based on measurements of contact resistance for the shaft-partial insert geometry (multiple contact). It is shown that contact resistance is a more sensitive parameter compared to the coefficient of friction.     

Computer simulation of Lorentz electron micrographs of thin magnetic particles

Lorentz electron microscopy is a powerful tool for high-resolution studies of magnetic structures, not only in continuous thin films, but also in spatially limited, i.e. individual particles. In addition to the experimental studies of magnetic particulate media it is interesting to simulate images in order to compare them with experimental results, as it is practiced in high-resolution electron microscopy. This paper introduces a software package which simulates the Lorentz microscopical image of magnetic structures in thin particles. While other simulation programs deal with infinite magnetic films with homogeneous thickness, the major difference in our calculation is that we take into account the finite dimensions of the particle for specimens of various sizes and shapes. That means the phase shift due to the inner potential depending on the geometrical shape of a magnetic particle is added to the phase shift depending on its magnetic microstructure. The following article presents the computation methods and its results and compares it with experimental findings.     

Effect of roughness and poisson's ratio on deformation conditions in the surface layers of contacting bodies

The effect of surface roughness and the Poisson ratio on the deformation of the surface layers of contacting bodies was investigated. The results from the model derived confirm experimental findings regarding the wear mechanism.