坐标测量机上圆度误差包容评定的算法

本文把最小外接圆、最大内接圆和最小区域圆度误差的评定问题都表述为minimax 问题,并建立线性数学模型,采用统一的方法求解。实践表明本文方法通用、有效、稳定,适用于坐标测量机。     

复杂线轮廓度误差坐标测量的数据处理方法

本文把平面上复杂轮廓的设计曲线能一地表示为参数矢函数描述，运用微分几何理论，导出被测工件上测点到设计曲线的距离函数，建立复杂发线轮廓度误差坐标测量的数据处理模型。文章对算法进行了精度分析，并且设计加工了一个凸轮试件，通过坐标测量，用本文方法精确、快速地计算出凸轮的轮廓度误差。     

三坐标测量机测量形位误差应注意的问题

本文对三坐标测量机测量形位误差应注意的几个问题进行探讨。     

坐标测量机测量齿轮形位偏差不确定度评估方法和实验

介绍了坐标测量机测量齿轮形位偏差不确定度的评估思路及计算方法，通过试验找出了坐标测量机测量齿轮参数的主要不确定度来源，并阐述了提高测量准确度的途径及如何确定被测齿轮的精度级别。     

PSD在形位误差测量中应用

直线度的测量，是形位误差测量中的重要项目，工件表面或机器运动导轨的直线度，往往又是机械设备或精密仪器的精度保证，直线度的测量有许多传统的方法，如自准直仪法，电子水平仪法，打表法，激光干涉法等，在这些方法中，要么测量安装困难，要么测量精度不高，限制了这些测量方法的应用范围，本文提出了一种基于ＰＳＤ（ＰｏｓｉｔｉｏｎＳｅｎｓｉｎｇＤｅｔｅｃｔｏｒ）接收器的简易，快速的测量方法。     

坐标测量机上建立测量坐标系的理论与方法

本文研究了在三坐标测量上测量零件时，建立测量坐标系产生的测量误差，指出了用测量坐标系体现基准时。基准要符合最小条件，并论述了三种建立测量坐标系的方法，其中多点法中盾线拟合法还可以对直线度，平行度，垂直度等形位误差进行测量与评定，收到了满意的效果。     

在坐标测量机上测量圆度误差

本文提出应用四坐标齿轮测量机进行工件圆度误差测量,利用线性规划的最优解进行圆度误差评定的方法。实际应用表明这种测量技术行之有效,测量准确度可达±2.5μm,满足实际生产要求,对提高测量设备的利用率具有一定的意义。     

在坐标测量机上检测复杂曲面形状误差的理论与方法研究

 介绍了在三坐标测量机上测量和评定面轮廓度误差的数学模型,和应用最优化方法用Ｔｕｒｂｏ  Ｃ语言编制的计算机程序,经校核验证,该算法符合形位公差国家标准的有关规定.     

Analysis of Temperature Measurement Errors Due to the Inaccuracy of the Model of a Computer-Aided Measuring Transducer

The series of models of temperature sensors described are based on the concept of measuring computer-aided transducers, according to which measuring and computer-aided transducers are considered as a single device.     

基金最佳使用研究

研究了一类决策问题——基金最佳使用:利用线性规划的知识,建立了三种不同情形下的最优基金使用问题的数学模型,并通过编程计算出最高奖金的数额,得出了最高年奖金的基金使用方法;引入数学期望,成功解决了国库券发行时间不定的问题.     

利用阿贝误差的对称性消除阿贝误差

本文论述了阿贝原则及误差的补偿方法，提出了利用阿贝误差的对称性来消除阿贝误差这一简单实用的方法。     

Geometrical design of thermoelectric generators based on topology optimization

This paper discusses an application of the topology optimization method for the design of thermoelectric generators. The proposed methodology provides the optimized geometry in accordance with various arbitrary conditions such as the types of materials, the volume of materials, and the temperature and shape of the installation position. By considering the coupled equations of state for the thermoelectric problem, we introduce an analytical model subject to these equations, which mimics the closed circuit composed of thermoelectric materials, electrodes, and a resistor. The total electric power applied to the resistor and the conversion efficiency are formulated as objective functions to be optimized. The proposed optimization method for thermoelectric generators is implemented as a geometrical optimization method using the solid isotropic material with penalization method used in topology optimizations. Simple relationships are formulated between the density function of the solid isotropic material with penalization method and the physical properties of the thermoelectric material. A sensitivity analysis for the objective functions is formulated with respect to the density function and the adjoint equations required for calculating it. Depending on the sensitivity, the density function is updated using the method of moving asymptotes. Finally, numerical examples are provided to demonstrate the validity of the proposed method. Copyright © 2012 John Wiley & Sons, Ltd.     

波纹形典型土壤动物非光滑体表的演化建模及其计算机实现

本文根据典型土壤动物具有很强的减粘脱土功能的几何非光滑体表特征,在地面机械仿生学的研究成果的基础上,建立了三种波纹形土壤动物非光滑体表的数学描述式,利用演化计算给出了波纹形土壤动物非光滑体表的数学模型。并开发出波纹形土壤动物非光滑体表的演化建模软件。     

The greatly misunderstood erythropoietin resistance index and the case for a new responsiveness measure

Introduction The optimal use of erythropoiesis stimulating agents (ESAs) to treat anemia in end stage renal disease remains controversial due to reported associations with adverse events. In analyzing these associations, studies often utilize ESA resistance indices (ERIs), to characterize a patient's response to ESA. In this study, we examine whether ERI is an adequate measure of ESA resistance. Methods We used retrospective data from a nonconcurrent cohort study of incident hemodialysis patients in the United States (n = 9386). ERI is defined as average weekly erythropoietin (EPO) dose per kg body weight (wt) per average hemoglobin (Hgb), over a 3‐month period (ERI = (EPO/wt)/Hgb). Linear regression was used to demonstrate the relationship between ERI and weight‐adjusted EPO. The coefficient of variation was used to compare the variability of Hgb with that of weight‐adjusted EPO to explain this relationship. This analysis was done for each quarter during the first year of dialysis. Findings ERI is strongly linearly related with weight‐adjusted EPO dose in each of the four quarters by the equation ERI = 0.0899*(EPO/wt) (range of R² = 0.97–0.98) and weakly linearly related to 1/Hgb (range of R² = 0.06–0.16). These correlations hold independent of age, sex, hgb level, ERI level, and epo‐naïve stratifications. Discussion ERI is strongly linearly related to weight‐adjusted (and nonweight‐adjusted) EPO dose by a “universal,” not patient‐specific formula, and thus is a surrogate of EPO dose. Therefore, associations between ERI and clinical outcomes are associations between a confounded EPO dose and those outcomes.     

超精密齿轮齿距累积总偏差测量装置的改进及其自动测量系统的设计

在明确齿轮齿距累积总偏差的相关概念的基础上,对相对测量法和绝对测量法进行进一步分类,并对各自的应用范围和特点进行分析.同时,遵循测量原理并采用高精度的元器件搭建了绝对测量法检测超精密齿轮齿距偏差的测量平台.通过Visual Basic 6.0语言设计合理的测量操作、图表处理及误差分析界面的过程,使操作简单,图表显示准确清晰,实现对1～2级超精密齿轮齿距累积总偏差测量装置的改进及其自动测量系统的设计.     

板材中甲醛释放量测定方法探讨

在乙酰丙酮和乙酸铵混合液中,甲醛与乙酰丙酮反应生成二乙酰基二氢卢剔啶,在波长为412nm时,测其吸光度,然后计算其含量。干燥器法采用蒸馏水为吸收液,而穿孔萃取法用甲苯为萃取液,甲苯溶液为有机溶液,又有很强的毒性,所以干燥器法测定板材中的甲醛更有利于环境保护。