基于单稳频激光的端面距离微尺寸测量方法

搭建了一种用于端面距离微尺寸测量的干涉光路,分别以频率高度稳定的532nm波长激光和波长不确定度水平相对较差的633nm波长激光作为光源进行照射以获取干涉图样。使用电荷耦合器件(CCD)传感器获取干涉图样,采用数字图像处理手段清晰化干涉图样,并利用条纹的像素距离计算干涉条纹级次差的小数部分,用多波长的小数重合法计算端面间距。通过系统的软件部分,利用数字图像处理的手段对干涉图像的质量进行优化,在较为简单的实验条件下实现精度较高的端面距离微尺寸测量。     

基于CORDIC算法的单频激光干涉信号处理系统半波长误差分析与消除

为了满足纳米级分辨率和高速处理,设计了基于CORDIC算法的激光干涉信号处理系统.研究发现信号处理系统存在半波长大小的粗大误差.对该半波长误差的特点与形成机理进行了研究,研究表明该半波长误差的根源为小数相位测量存在一定的误差区间,在干涉信号相位零点附近,该误差区间导致小数相位处于[2π-,0+],具有不确定性;与整数相...     

红外拍频锁定型绝对距离干涉仪的研究

利用3.39μm波段双线氦氖激光器作光源实现了作者提出的拍波锁定绝对距离干涉仪新方案。在阐述绝对距离干涉计量的逐级精化理论和上述氦氖激光两级合成波测长方案的基础上,着重分析了双波长拍波锁定干涉测长原理,给出了实验原理图和部分测量结果。分析表明,拍波锁定绝对距离干涉仪的干涉条纹尾数测量精度已达5×10~(-4)。     

一种正弦相位调制光纤干涉条纹相位稳定方法

为了消除环境因素(尤其是振动和温度波动)在物体表面三维形貌测量中的影响,基于正弦相位调制(SPM)发展了一种光纤干涉条纹相位稳定技术。利用马赫-泽德光纤干涉仪结构和杨氏双孔干涉原理实现高密度的余弦分布干涉条纹投射。利用两光纤干涉臂端面的菲涅尔反射生成迈克尔逊干涉信号,由光电探测器(PD)检测后送入相位控制系统。采用相位生成载波的方法提取干涉信号的相位,并将生成的补偿信号闭环反馈给压电陶瓷驱动器,与正弦相位调制信号相加后共同驱动压电陶瓷,补偿环境因素带来的相位漂移,实现干涉条纹相位的稳定。环境因素对条纹相位的影响低于57 mrad,实验结果验证了该方法可行性。     

干涉条纹小数的测量

对高精度干涉条纹小数测量的方法进行了系统的介绍.就干涉条纹小数的定义、暗条纹中心的确定、量块中心长度测量的起始和终了位置进行了较全面的分析,实现了不确定度为2 nm的干涉条纹小数的测量.引用实验与国际比对结果理论分析予以验证.     

基于条纹图的微结构离面运动特性测量

为了测量微结构离面（Out—of—plane）运动特性,利用频闪显微干涉技术设计研制了微结构离面运动测试系统,首先采集微结构运动周期内不同时刻的一系列干涉条纹图,并通过SUSAN滤波算法对各干涉条纹图进行降噪处理,再利用5步相移算法从干涉条纹图中提取被测微结构的相位信息得到包裹相位的锯齿型条纹图,并采用质量导向图法进行去包裹处理,最后根据相位高度关系式可得到被测微结构运动周期内不同时刻的形貌图及其离面运动曲线。通过实验对正弦基础激励下硅微悬臂梁的离面振动响应进行了有效测量,且测量重复性小于10nm。     

用散斑干涉光谱分布检测瞬态温度

为了提高对瞬态温度检测的灵敏度,提出了基于散斑干涉条纹光谱分析的瞬态温度反演算法.系统利用散斑干涉形成干涉条纹,由于瞬态温度的变化会使材料应变,从而使散斑干涉条纹改变.被测表面形变前后获得的干涉条纹由面阵 CCD 采集,其对应的光谱密度分布函数也会发生相应的改变,即由散斑干涉条纹反演得到的中心波长振幅发生改变.通过对两次中心波长幅值的比值的检测和计算,即可获得被测的瞬态温度.在分析计算了瞬态温度变化与材料应变、材料应变与干涉条纹变化的函数关系的基础上,推导了瞬态温度变化与干涉条纹振幅及相位函数关系.实验采用660 nm 半导体激光器,SI6600型面阵 CCD 探测器,从获得的光谱分布函数中提取中心波长处幅值比值,通过计算和标定,最终温度检测精度可达到±2℃.相比传统的直接检测干涉条纹的变化量,由被测面形变量推导温度的方法精度提高了近一个数量级,其精度更高、检测均匀性更好、稳定性更好.     

调频激光干涉绝对距离测量技术及其信号处理

最最的绝对距离测量方法是非相干飞行时间测量法。随后，在小数重合法的基础上，产生了多波长干波绝对距离测量技术。随着半导体激光器的发展，８０年代又出现了调频干涉绝对距离测量方法，并很快成为一种新的测长技术。本文在综述绝对距离技术及方法的基础上，着重介绍了调频激光干涉绝对距离测量技术的一些新发展及其几种不同的信号处理。     

一种新的正弦相位调制干涉条纹相位稳定方法

在基于条纹投射的物体表面形貌测量中,温度漂移和振动是造成条纹相位漂移的主要因素。为了稳定条纹相位,在相位补偿系统(PCS)中运用峰值检测简化相位提取过程,发展了一种基于正弦相位调制的干涉条纹相位稳定技术。将光纤缠绕在柱形压电陶瓷(PZT)上,向PZT注入正弦驱动电压实现对干涉条纹相位的正弦相位调制。运用2×2光纤耦合器分光,结合马赫-泽德干涉与杨氏干涉结构实现条纹投射。光电探测器检测两端面反射信号形成的迈克尔逊干涉信号,从中提取环境因素引起的相位漂移,运用旋转坐标数字机进行快速反正弦计算,生成的补偿信号与调制信号叠加后共同驱动PZT,实现条纹相位稳定。实验结果表明,条纹相位稳定精度为5.5 mrad,较好地消除环境因素引起的相位漂移。     

单片机控制的高精度Michelson干涉型波长计

设计了Ⅻehelson干涉型激光波长计干涉条纹的单片微机计数硬件电路,编写了8254计数和KeilC51波长运算程序．为提高仪器的测量精度,在硬件和软件上提出了新的设计方案．两个8254计数器可以在单片微机的控制下自动从参考光脉冲信号的下降沿开始对参考信号和被测信号同时计数;参考激光干涉条纹计数满1500000后。参考信号和被测信号的计数器可以同时被自动锁定;单片微机得到锁定信号后,完成两个计数值的读取、波长运算、10次移位平均和7位波长显示．对633nm和532nm两种稳频激光波长进行了实际测量,测量数据表明该计数系统使波长的测量精度达到2×10^-7．     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...