一种新型大尺寸长度校准装置的研制

介绍了一种新型的大尺寸长度校准装置,该装置解决了激光干涉仪等高精度大尺寸长度测量仪器的实验室校准与溯源问题.通过采用三路相干光进行测长,根据两辅助光路与主光路的测长偏差计算阿贝角,实现了阿贝误差的实时补偿.利用标准双频激光干涉仪测试了阿贝误差的补偿精度,35 m测量范围内的比对误差小于±3μm.测量精度达到了单光路同轴测量的水平.     

一米测长机改造研究

采用上海光学仪器厂JDS-1型接触式干涉仪关键部件对卡尔·蔡司·耶拿[Carl Zeiss Jena]一米测长机进行改造将其原有测量精度提高一个数量级,改造后可用于3等量块100mm以上到1000mm的高精度比较测量。本方法优点成本低,易于实现,读数直观可靠稳定,干涉管可根据需要定相应分辨率,光路全程均为光学器件,方法可逆,经济实用。     

正压漏孔校准装置优化设计

针对目前正压漏孔校准工作中存在的测量下限指标低、测量不确定度大等问题,提出了正压漏孔校准装置的优化设计方法.采用特殊设计,将定容室的容积减小到10 mL以下,降低了气体累计时间,延伸了测量下限.采用主、被动相结合的恒温方法提高恒温精度,使得测量系统温度变化在校准时间内小于0.02 K,减小了温度漂移引入的虚流量及测量不确定度.在恒压法正压漏孔校准方法中,提出采用直径小于1 mm的精密细活塞及适用的动密封结构.可以将测量下限延伸到10-7Pa·m3/s 量级.通过以上方法,可使正压漏孔校准装置的测量下限优于5×10-7 Pa·m3/s,不确定度小于5%,同时具有较高的工作效率.     

新Moser—Poltz压缩计中的激光干涉测量技术

本文介绍了在新结构的 Moser—Poltz 压缩真空计中,采用了激光干涉测量技术,使小室下缘汞平面的平面度可控制在1.6×10~(-4)mm 以内,测量粗管内汞柱高度变化的不确定度小于1.7×10~(-2)mm(以3δ计算)。从而有效地提高了该计的压力测量精度,成为10~(-6)～10~(-2)Pa 压力测量范围内的一项实用真空标准。     

基于单目立体视觉的机床几何误差辨识方法

针对视觉测量手段中成本与精度不能兼顾的问题,提出基于单目立体视觉的机床回转轴几何误差辨识方法。为实现回转轴全量程运动精确描述,基于误差放大思想,设计了基于周向均布精密哑光靶球的高匀、高精、高信噪比成像靶标。提出了单目立体成像光路参数仿真分析方法,定量分析并选取系统结构参数。基于单目立体标定结果,根据序列图像重建得到回转轴三维轨迹。精度验证及误差辨识实验表明:系统的RMSE为0. 049mm,小于平均偏差的1/3,满足测试需求。     

基于同心圆现场标定的实时畸变校正方法

为了提高光电测量系统对火炮重要静态参数——弯曲度的测量精度,提出了一种基于同心圆现场定标的实时畸变校正方法,并设计了一套自定中测量装置.首先调整测量装置中靶标的水平和竖直定位,消除偏心畸变;然后采用曲率估计的方法实时提取现场标定同心圆,对光学系统的畸变变化情况进行检测;最后根据检测对弯曲度的测量结果进行校正,进而实现弯曲的高精度测量.对焦距为6.00mm的弯曲度测量系统进行多点测试,实验结果表明:该方法具有较强的稳定性,校正精度高且实时性好,与传统的校正方法相比,校正后的测量偏差由士0.15mm提高到±0.05 mm,且单点校正时间小于0.49 s,有效地提高了系统的测量精度.     

基于激光三角法反射式光路设计的小角度测量

介绍了激光三角法反射式光路设计的基本原理、光路结构和成像系统;给出了在不同实验参数下的测量范围、测量精度和测量误差,并对测量范围和测量精度与各主要参数间的变化关系进行了分析。实验表明,该方法可以实现小角度的高精度测量,且其测量范围和测量精度可以进行动态调节。     

采用单片式探测器实现辐射通量定标

在基于双单色仪的辐射通量定标中,为了克服陷阱探测器视场小、孔径小的缺点,提出了采用单片式探测器替代陷阱探测器进行辐射通量定标的方法。采用只与光路垂直的一片硅探测器,使其光敏面与孔径光阑几乎重合,以增大探测器的孔径角。同时为了保证测量精度,采用偏置电流极低的运算放大器OPA128,并且增大了反馈电阻,以增强对弱信号的响应。采用单片式探测器对400—1000nm波长范围内进行辐射通量定标,系统不确定度包括：探测器响应拟合不确定度7‰,从陷阱探测器到单片探测器的传递不确定度3．14‰,光源波动小于1‰,系统重复性的不确定度3‰,最终合成不确定度为8．3‰,测量结果满足要求。     

导弹飞行低转速测量方法研究

目的：解决导弹初始段低转速的测量问题，方法：采用单台狭缝相机对地面平射导弹低转速进行测量处理的方法，并给出了该方法在导弹低转速测量中的测量精度和适用范围。结果与结论：表明测量精度优于0．3r/s，最后得出了转动速度大于2．5r/s时完全单可以利用单台设备进行转速测量，在转动速度小于2．5r/s应该采用两站联测的结论，其测量模型适用两种测量方案。     

精密离心机动态失准角测试系统的设计研究

分析了惯性导航用精密离心机动态失准角测量中存在的问题,提出以双轴光电自准直仪为核心测量仪器的失准角测量系统,在测量系统中采用真空光路进行光路气流屏蔽,减少了由于空气扰动带来的误差。对构成测量系统的各环节进行了误差分析与设计,理论分析与台面实验表明系统测量精度可达到0．2″。     

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.