二级角度块角度偏差测量结果不确定度评定

一、测量原理使用最大允许示值误差为±2″的测角仪,依据JJG70-2004《角度块》检定规程规定的方法对工作角为50°的二等角度块角度偏差进行连续测量,得到测量结果分别为-21″、-24″、-19″、-18″、-17″、-23″、-19″、-20″、-21″、-18″。取该组数据的平均值为输入测量的最佳估计值-20″,测量结果为49°59′40″。     

光学分度头示值误差检修中的一些问题

一、示值误差的检定光学分度头是目前工厂计量室常用的测角仪器。其规格有刻度值为:2″、3″、6″,10″等不同型号。示值误差的检定有两种方法,对刻度值i=10″或低精度的分度头采用四方形铁(±5″)和测微表(0.001±0.5微米)组合检定;对刻度值为2″、3″、6″的分度头采用1″自准直仪和正多面棱体组合检定。     

基于小波神经网络和PSO的动态误差溯源方法研究

针对动态测试系统在测试过程中出现的精度损失问题,提出一种基于小波神经网络和粒子群优化算法相结合的动态误差溯源方法。该方法基于全系统动态精度理论,通过设计小波神经网络对动态测试系统的输出总误差进行分解,并采用粒子群优化算法对分解结果进行分析,追溯到误差产生的模块。仿真结果表明:该方法能够快速有效地完成误差溯源,并且溯源准确度达到10-2,具有可行性和应用性。     

铁路车辆偏载自动检测系统的研制

本文介绍了一种对铁路列车车辆进行自动偏载检测的测试系统。系统通过采用嵌入式控制模块实现了现场数据采集、远距离控制。使得用户在洁净的工作室就能实现对恶劣工业现场的控制。在工控机发生故障或死机时，测试系统其它环节依然能正常工作。在对测试系统的软硬件部分作了必要的说明的同时，对测试系统存在的误差进行了分析。     

激光跟踪仪角度采集系统设计及误差修正研究

高精度的角度采集和测量是激光跟踪仪实现跟踪和精密测量的关键。针对激光跟踪仪中采用的圆光栅编码器,本文介绍了一种基于FPGA的数据采集系统的设计与实现方法。该采集系统分为滤波、计数、通信三大模块。数字滤波模块用于消除跟踪控制过程中跟踪头振动、抖动产生的信号干扰;计数模块实现方波脉冲的倍频、辨向及计数;通信模块实现跨时钟域的数据传输。系统通过Modelsim仿真及实验测试验证了方法的可行性与可靠性。采用谐波分析方法对角度误差进行了修正,测量误差由3.5″降低到1.5″。本文设计的角度采集系统及谐波分析误差修正方法具有一定的通用性,可广泛应用于相关领域。     

基于模糊PID控制的汽车座椅测试系统的设计

汽车座椅静载强度的测试直接关系到乘员的人身安全,其测试系统要求控制精度高,超调量小以及稳态误差小。传统的PID控制由于参数整定差,不能满足汽车座椅测试系统高精度的要求。本文将模糊控制与PID控制结合起来,设计了模糊PID控制器。通过MATLAB/Simulink对控制器的仿真分,比较传统控制和模糊PID控制的性能,验证模糊PID控制器的优越性。最终试验结果表明:模糊PID控制系统的超调量在3%以内,稳态误差在0.7%以内,具有较高的控制精度,符合测试要求。     

二维工作台角度误差实时补偿研究

为减小二维工作台在运动过程中俯仰角、偏摆角对其定位、测量及加工精度的影响,提出一种实时补偿二维工作台角度误差的方法。将激光测量系统作为角度反馈装置,基于压电陶瓷致动器和柔性铰链设计出的六自由度微动工作台作为补偿机构,通过软件控制微动台中压电陶瓷的输入电压,达到补偿工作台角度误差的目的。实验结果表明:二维工作台在50 mm的运动范围内,角度误差实时补偿后,向X方向运动的角度基本可以控制在±3″内,向Y方向运动的角度基本可以控制在±2″内。该方法能够实现对二维工作台角度误差的实时补偿,对提高工作台的定位精度有参考价值。     

光斑质心亚像素定位误差的实验研究

根据误差的来源将光斑质心亚像素定位误差归类为随机误差和系统误差,提出一种简单有效的实验方法对光斑质心定位误差进行定量测试.利用高精度一维电动平移台、POINT GREY Flea2-14S3 CCD相机和LED光源构建了测试系统,对测试结果进行研究和讨论,发现了测试系统LED光斑质心定位系统误差的周期性变化规律,计算得到了基于Flea2-14S3 CCD相机的光斑质心定位随机误差为0.018 pixels,系统误差为0.06 pixels,总体误差为0.063 pixels(约1/15 pixels),能够应用于以光斑质心检测为手段的测量系统中.实验表明,该测试系统可以作为估算光斑质心定位误差大小的一种有效的手段.     

离子束刻蚀机工作台的改造

合肥国家同步辐射实验室光学元件组现承担 863 -4 16-2子项目“用于激光驱动靶面均匀照明位相片的制造”。在位相片的制造过程中所遇到的关键问题之一是如何使基片上的掩模板中心和基片中心精确对准 ,要求对准台套准误差小于 10μm,重复套准误差小于 2 0μm,刻蚀基片的综合误差小于 30μm,静态真空度小于 1× 10 - 4Pa。为此我们对 L KJ-1C-D-150离子束刻蚀机进行了改造 ,设计了一套三维可调的掩模工作台 ,并对其进行了测试 ,给出了测试后的刻蚀结果     

强化冷凝管外侧制冷剂冷凝换热试验分析与新计算方法研究

对外径分别为1″和0.75″的强化冷凝管进行管外冷凝换热性能测试,引入冷凝管管外传热强化因子(h_(o-multiplier)),将其在常用热流密度范围内的平均值作为不同管型冷凝管管外换热系数的评价指标,并对该评价指标进行理论和试验对比分析。结果表明,该评价指标在常规工况条件下与测试值的偏差在±10%以内,满足工程设计要求。     

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.……     

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.     

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 ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.