现代设计与"中国制造"

世界制造中心正向中国转移,但是,在繁荣的"中国制造"背后却有一个不争的事实中国自有品牌较少,产品技术含量不高,自主创新能力较弱.通过分析我国企业现状阐述了开展现代设计的必要性,论述了进行现代设计首先要解放思想,以创新设计为例讲述了现代设计方法,并简述了现代设计方法的综合运用.     

船载"动中通"圆锥扫描系统结构设计

文中阐述了“动中通”圆锥扫描自动跟踪系统的原理、结构组成以及实现方案,分析了圆锥扫描系统的振动源,并采取了相应的减振措施,在设计过程中采用了CAD与Matlab相结合的二次开发方法对副面进行了优化设计,并提出了进一步提高系统性能的方法。实验测试表明,该系统能够获得较高的跟踪精度和跟踪实时性,能够使天线稳定地对准卫星。     

"火花状"直线度图的处理方法

在龙门刨床或龙门导轨磨床窄长工作台运动直线度检测中,采用了“火花状”直线度图的处理方法。文中介绍了采用火花状直线度图的计算方法以及测量中应注意的相关问题,并指出在此时用通常的直线度处理方法是不合适的。     

激光雕版机加工"扫描"图形的方法

阐述了一种以"CAXA电子图板2005"作为"中介"软件,使激光雕版机能够间接接受"扫描"图形进行加工的方法,并以实例介绍了该方法的操作过程.     

关于"三要素"的重新认识

求解一阶电路的三要素法似乎是很熟悉的课题。但是对它的认识是否到位、文字的表达是否严谨还需要进一步探讨,对三要素求解方法进行了分析和证明。     

用"表格法"评定平面度误差

提出评定平面度的一种新方法──表格法,并在理论上论证了这种方法的正确性和可靠性。这种方法的优点是数据处理比较简单、直观,应用比较方便。     

柴油机"飞车"与"游车"故障分析与诊断维修

以“飞车”与“游车”的形成机理为切入点，着重分析了柴油机“飞车”及“游车”的故障症状、原因，提出了对疑难故障的诊断检修方法。     

如何制定县市"十二五"农机规划

针对有些县市无成熟农机规划的现状,提出了制定和完善农机规划的科学思路及有效方法.     

打造平安企业"三部曲"

本文阐述2004年度公司实施“完善安全生产管理制度、推行‘一法三卡’安全现代管理方法和开展班组安全生产竞赛”二三部曲的主要做法,从而全面落实“安全第一、预防为主”的方针,杜绝了事故灾害,取得建企以来安全生产管理最佳业绩。     

铸铁平板"像素检测法"的应用

对“像素检测法”在铸铁平板接触点面积检测中的应用进行了研究,指出在实际应用中,保证检测结果准确与可靠的关键是保证“信息采集”与“信息处理”的可信度,并提出了具体解决方法。     

Influence of measured objects parameters on CMM touch trigger probe accuracy of probing

Influence of the measured objects parameters on coordinate measuring machine (CMM) touch trigger probe inaccuracy of probing is investigated. Factors such as material stiffness of measured workpiece, its surface shape and roughness are taken into consideration. The measuring method out off CMM, based on a rotary table and a reference axis is applied for tests. The concept is based on measurements of the distance between reference and triggering points in various directions. The reference points are established by the rotation of a precise rotary table. The statistical analysis of variance and regression is applied for data analysis.     

An innovative algorithm for statistic sampling of measured points and simplifying measuring probe orientation for sculpture surfaces

As living standards have improved, the requirements of appearance modeling variables have also increased. Although several CAD systems can design and modeling needed products with complicated geometric, but the questions of measuring methods and workpiece error-detection are also growing. For the contact measuring method, besides measuring collision and probe orientation, the sampling points and their distributed locations are the important factors that influence measuring time as well as precision. In this paper, the sampling statistics technique was used to calculate the minimum number of sampling points, which will tally the contour tolerance requirements of the measured surface. Next, the suitable locations for sampling points will be carried out using the one-half sampling distribution method. Finally, the 2D space picture of measuring characteristic of five-axis CMM (CMM-space) was developed for measuring probe’s orientation in the measuring process. As a result, an algorithm of measuring characteristic matrix of five-axis CMM (CMM-matrix) and the minimum times of the measuring probe’s placement was derived to reduce the measuring time and improve the measuring efficiency.     

Elastic constants of langasite and alpha quartz at high temperatures measured by antenna transmission acoustic resonance

A method for measuring elastic constants of piezoelectric materials at high temperature up to 1224 K is proposed. It determines all independent elastic constants by measuring resonance frequencies of a rectangular parallelepiped piezoelectric specimen contactlessly using its own piezoelectricity with an antenna. Without using conventional contacting piezoelectric transducers, vibrational sources are excited directly in the specimen by the oscillating electric field. Capability of the method is demonstrated by measuring the elastic constants of langasite at high temperature up to 1224 K, and temperature coefficients of the elastic constants are determined. In addition, elastic constants of alpha quartz are measured at high temperature up to just below the alpha-beta phase transition temperature. Considering the local deformation with temperature increment, an interpretation based on the strain energy reduction is proposed for the unusual temperature dependence of C(66). Furthermore, the internal-friction tensor is measured, and the relationship between the observed anisotropy in internal friction and the structural evolution with temperature increment is discussed.     

Noise and interference in measured NMR images

This article describes the measurement and evaluation of noise and interference in experiments with nuclear magnetic resonance (NMR). Their presence in experimental results causes irreversible artefacts in measured images or errors in the calculated values of investigated quantities. Noise in the signal also reduces the sensitivity of the measuring instrument. From the point of view of results, there is no significant difference between noise and interference. Both signals are multi-frequency or have a changing frequency, meaning that they must be characterised using their power or root mean square (RMS) values of voltage or current. The RMS voltage at the output of the NMR receiver with a receive coil in its input was measured using an NMR console and compared to thermal noise voltages of known sources, e.g. resistors with known resistivity in the input of their receiver. The comparison indicates the possible inherence of interference. The noise measurement using the console was performed in two ways: using an acquisition only and using a complete measuring NMR sequence, which resulted in an image. The results served to test the quality of the hardware used for NMR experiments. It has been proven that the presented method is suitable for testing and improving the signal-to-noise ratio of NMR scanners without the need for the accumulation of seldom-used expensive instrumentation.     

基于单片机的发动机转速测量系统的分析研究

本文介绍了基于霍尔脉冲发生器与单片机的转速测量装置的组成及转速的测量方法,分析了该种测量方法的测量精度以及测量精度与转速的关系。并讨论了转速测量数据的滤波方法。     

The effect of tip size on the measured Ra of surface roughness specimens with rectangular profiles

When measuring rectangular and trapezoidal profile roughness specimens, the stylus tip increases the measured profile peak width and decreases the measured valley width. This can cause either an increase or a decrease in the apparent roughness average Ra, depending on the tip size and the ratio of peak width to valley width. Sometimes the change is larger than the combined measurement uncertainty from other sources. This raises the question as to whether measured surface parameters should be corrected for the effect of tip size.     

热双金属片挠度值测量精度分析

热双金属片挠度值测量是检测其热弯曲一致性及稳定性的重要指标。介绍了热双金属片工作原理,分析悬臂梁法热双金属片热弯曲变形过程中产生的水平位移对各点挠度值测量精度的影响。利用CCD激光位移传感器非接触测量热双金属片被测面各点挠度值,通过补偿水平位移误差提高热双金属片各点挠度值测量精度,并实验验证各点挠度测量值的准确性。     

用于弧齿锥齿轮铣刀盘调整的非接触式测量方法

采用接触方式对弧齿锥齿轮装配式铣刀盘刀刃径向跳动测量时存在接触力的影响,由于接触力大小不定,增加了测量系统误差.采用激光位移传感器对弧齿锥齿轮装配式铣刀盘刀刃径向跳动进行非接触式测量.通过对测量数据分析,数据自动提取,实现对切削刃径向跳动的测量.该方法有效地避免了传统的接触式测量的不利因素,提高了测量的重复精度及测量效...     

实验数据的自动拟合方法

本文提出了一种应用神经网络对实验数据进行自动拟合的方法。文章给出了数据拟合的求解过程,利用神经网络自适应性的特点进行拟合的方法,并给出数值仿真的实例。     

解析GBT3177-1997《光滑工件尺寸的检验》

分析并解释GBT31T7—1997《光滑工件尺寸的检验》,提出工件车间检验测量方法和选用量具应注意的问题。