光栅纳米测量中的系统误差修正技术研究

详细研究了光栅纳米测量系统的误差特性 ,以及利用激光干涉仪对高精度光栅测量系统的系统误差进行检测、并在信号处理中予以补偿和修正的方法。实验表明 ,通过这种系统误差修正方法对周期累计误差和细分误差同时进行修正 ,能够大幅度地将计量光栅系统的测量准确度从微米或亚微米量级提高到纳米级水平 ,以实现光栅纳米测量。     

炫耀光栅位移测量系统的精度试验

炫耀光栅位移测量系统采用尤学倍增与电子细分相結合的方法,使系统的分辨率达到0.4微米。与金属线纹尺比较测量,系统在300毫米内的极限误差为1.5微米。试验证明炫耀光栅位移测量系统具有较高的精度,如能进一步提高标尺光栅的刻划精度,并相应地提高分辨率,系统的实际精度还可以提高。     

浅谈超精密加工机床的新技术及发展

1引言 随着现代科技的发展应用,对零件的加工E精度要求从微米级提升到亚微米级、纳米级。超精密加工技术是实现这一目标的重要途径,其发展程度体现了一个国家制造技术的发展水平。     

电子束曝光机工件台系统结构设计误差分析

本文首先扼要地阐述了作为电子束曝光机主要组成部分的工件台系统的功能要求,分析了影响工件台位移测量精度的各种因素并进行了粗略比较。指出了降低测量误差的具体措施,对能制作微米、亚微米线条的精密工件台的直线运动精度和反射镜的精度提出了具体的设计参数。     

基于X光光刻的亚波长光栅

描述了一种新的亚波长光栅的微细加工技术，即X光光刻得到相应的亚微米级的线宽图形，再利用显影技术获得了高深宽比的立体亚波长光栅．用此纳米加工技术获得了栅距为500nm、250nm、150nm，光栅高度为1900nm的特殊纳米光栅模具，开发了纳米无反射结构，并研制成功了亚波长光栅．该亚微米线宽微细加工技术可用于布拉格光栅、DVD读写头、无反射表面等需要亚微米结构的器件中．     

高精度衍射光栅干涉仪的研制

提出了一种新型的激光衍射光栅干涉仪测量系统,以光栅衍射原理和偏振光学为理论基础,配合正交信号的解相位细分原理,使得该系统可以达到纳米级分辨率.由于光栅干涉测量系统以光栅栅距作为测量基准,相对于传统干涉仪,光栅尺系统受环境因素造成的测量误差影响较小.通过实验校正,得到不同行程范围内光栅干涉测量系统的纳米级重复性误差,新型的激光衍射光栅干涉仪测量系统适合于较长行程的高精度位移测量.     

长度光栅测量系统的误差修正技术

长度测量技术是近几年工程建设、工业生产等领域研究最多的问题,其测量系统分辨率早已经达到微米、亚微米乃至纳米等级。本文就长度光栅测量工作中出现的误差来源分析,简单的阐述了有关误差修正技术,仅供同行工作参考。     

大量程触针杠杆式轮廓仪的非线性误差分析和补偿

介绍了一种基于光栅干涉测量原理的大量程、高精度触针杠杆式表面形貌传感器,并对传感器在大量程测量时的非线性误差进行了分析。测量时轮廓仪在水平和垂直方向上都会由于测杆绕固定支点的转动而产生非线性误差,为此提出了一种对水平和垂直方向上非线性误差进行校正的新方法。通过使用大量程、高精度的一维垂直微位移工作台和标准楔形斜块进行误差校正。最后分别给出校正前后误差曲线,并进行对比。通过分析可知,此方法可以有效减小测量时的非线性误差,大大提高轮廓仪在进行大量程测量时的精度,从而实现大量程、高精度测量。     

CCD精密测角系统

本文提出了一个由线阵ＣＣＤ，８０３１单片机和多面镜构成的可在３６０°内实现高精度角位移测量的系统，对其构成原理，可达精度及影响精度的因素进行了理论分析。解决了常见ＣＣＤ位移测量系统中量程和精度成反比的限制，实现了整个圆周上０．０１ｍｒａｄ的高精度测量。     

基于图像配准技术的二维平台位置参数视觉测量

提出一种基于图像配准技术测量移动平台二维平移、旋转等参数的视觉测量方法．固定基准图和镜头,使CCD随平台在基准图的像平面内移动或旋转,再由图像配准技术对当前CCD接收到的图像在整个像平面内的位置进行定位,从而可实现微位移平台位置参数的测量．对基准图进行分块设计,并且对每一分块进行二进制编码．如果保证至少有一分块落到CCD成像区域内．实验结果表明系统的位移测量精度可达到亚微米级．     

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.     

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...     

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.     

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.……     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

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.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

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.……     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.