快速反射镜系统用光栅测微仪

为了精确控制FSM系统中平面反射镜的偏转角度,研制了专用型光栅测微仪对其进行位置测量,以实现系统的闭环控制.在明确了FSM系统对测微仪应用需求的基础上,根据其技术原理,对光栅测微仪的小型滑轨、标尺光栅图案、指示光栅图案、绝对零位编码、指示光栅移相以及接触探头分别进行了设计与选择.经精密加工、装配、调试后,所得光栅测微仪...     

Talyrond300型圆度仪中测角圆光栅的更换与调试

介绍了Talyrond300型圆度仪中测角圆光栅故障的检测和维修方案。在充分了解该型号网度仪上圆光栅测角系统性能参数的基础上,重新制作标尺光栅,保留原指示光栅和光栅信号处理电路不变,通过对标尺光栅和主轴的同轴度、光栅副的间隙以及高质量莫尔条纹的调试实现了对圆度仪光栅系统的修复。     

成像式光栅自准直测角方法研究

针对目前光电自准直仪难以做到既有高分辨力同时又有大的测量范围的不足,提出一种成像式光栅自准直测角方法。该方法将成像式光栅方法、自准直测角技术相结合,利用标尺光栅像和指示光栅形成的光栅副反映被测物体的角度变化。试验结果表明,该系统接收到的光栅信号稳定,满足光栅计数的要求,成像式光栅自准直测角方法原理可行。该方法避免了光栅副间隙带来的误差,具有大量程及较高的分辨力。     

一种新的二元条码设计与绝对式光电位置编码方法

提出一种新的二元条码设计方法,可用于绝对式光电位置编码.传统的光电编码器主要基于莫尔光栅条纹技术,把位移量变为电脉冲,结构简单,但由于增量式相对测量方式,从而使得光电编码器的应用受到了限制.本文提出的二元条码设计方法,在单码道上设计了包含三种频率信息的光栅,采用二元脉冲编码调制和误差扩散的方法形成二元条码标尺.在光电位置编码器中,标尺上某一段的条码就成像在线阵CCD上.对CCD获取的该段条码信息进行傅里叶变换,滤波和逆傅里叶变换,得到三种频率光栅的相位信息,采用小数重合法得到该段条码的绝对相位分布,从而得到绝对位置信息.新的方法保留了单码道光栅莫尔技术结构简单的优点,同时又能像多码道光栅编码器一样实现绝对位置测量.文中给出了编码方法的详细描述,条码信息处理方法,计算机仿真实验结果,最后给出了绝对式光电位置测量的实验结果.本文提出的方法在绝对式光电位置编码器和数字水准仪等领域具有一定的应用前景.     

反射光学式位移检测系统

系统由半导体激光器、聚焦镜头、反射式标尺光栅、四裂相指示光栅和光电接收元件组成。该系统具有光学两倍频作用和大光栅副间隙下使用及间隙对莫尔条纹信号调制度不敏感等特点,并且整体结构分离式、小型化和轻型化,在各类精密测量装置和精密加工仪器中将得到越来越广泛的应用。本文介绍这种反射光学式位移检测系统的结构原理,系统特点和应用。     

结构光深度获取系统校准方法

针对基于相位调制的结构光用于深度获取时,投影系统、图像采集系统光瞳中心不等高而引入测量误差,提出一种测量系统校准方法。该方法以N帧正交光栅像与一立方体物体为辅助,根据光场中立方体边缘的阴影位置及其表面光栅栅线变形情况实现系统的粗校准;通过计算立方体深度在光场水平方向引起的相位变化量,指导系统的精校准。该方法可为基于结构光的深度获取装置校准提供理论指导,为非经验装调工作者提供技术支持,实验数据论证了该方法的有效性。     

扩束光纤与宽波导光栅的光耦合特性

为了研究光纤与宽波导光栅的有效耦合,基于高斯光束与波导光栅的光耦合理论,以30μm宽波导光栅为研究对象,利用矩阵光学和高斯光束理论分析和设计了一种扩束光纤,并通过分析其耦合损耗,建立了扩束光纤与波导光栅耦合模型.优化所设计扩束光纤的结构参数后,得到束腰半径为10.8μm的输出光束.最后分析了扩束光纤的结构容差,并讨论了所设计扩束光纤的输出光束、单模光纤的输出光束以及束腰半径为16 μm的自由空间高斯光束各自在光栅表面的位置变化对光栅耦合效率的影响.可知扩束光纤输出的光束与单模光纤输出的光束相比具有较大的位置容差,与束腰半径为16 μm的自由空间高斯光束相比,光耦合效率基本相同.     

应用两点法对EDG器件的优化设计

应用两点法对EDG器件进行了优化设计,将器件中凹面光栅对中心波长的无像差点由一个 增加到两个,并由此确定各光栅槽面的位置及输出点的位置。利用标量波动衍射理论进行了数值模拟,结果表明,该设计能明显降低系统像差,改变了传统设计方法在大通道数情况下像差过大、边缘通道性能劣化等问题。     

激光线位移传感器基本误差测得值的不确定度评定

本文介绍了用光栅式指示表检定仪测量输出为电流信号的线位移传感器的不确定度评定方法,为以后测量输出为电信号的线位移传感器的不确定度评定提供参考.     

圆光栅四象限式裂相刻划指示光栅的调整特性

圆光栅四象限式裂相刻划指示光栅的调整特性戚亮新（第一军医大学，５１０５１５）戴兴庆（上海机械学院，２０００９３）一、引言本文作者在研制一种增量式光电角度编码器的过程中，涉及到如何选择和设计指示光栅以求得到最好的效果。本文讨论了几种圆光栅指示光栅的布局...     

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 ...