二维并联跨尺度压电精密位移驱动平台研制

多自由度跨尺度精密位移驱动平台在光学计量检测、半导体制造、生物医学工程等诸多领域具有广泛的应用需求。针对串联多自由度压电驱动平台结构厚重的问题,结合压电柔性铰链机构和冲击驱动原理,研制了一款结构紧凑的二维并联跨尺度压电精密位移驱动平台。通过有限元仿真和实验测试验证其性能,结果表明：压电柔性铰链定子的静态位移为7.95μm,固有频率为11.80 kHz。低频步进位移和高频平滑运动测试表明：原理样机的步进位移分辨力为100 nm,平滑运动速度为4.96 mm/s,负载力达到100 mN以上。原理样机基本满足多自由度跨尺度精密位移驱动的技术要求,在微纳光学检测等系统中具有良好的应用价值。     

纳米级电容测微系统的研究

本文首先介绍了非接触式高精度电容测微仪的基本工作原理,进而详细论述了纳米级电容测微技术中所涉及到的非线性误差、环境噪声等关键技术问题,对典型驱动电缆方案作了比较。根据原理模型,给出了仪器的主要结构。对仪器自身产生的各种误差进行了详细的分析,并提出了相应的消除或修正方法。换用不同有效直径的传感器可以使仪器分辨力达到0.1nm,测量范围±2~±50μm,满量程非线性优于0.5%。该仪器可广泛应用于通过串口、USB口通信的高精度动、静态微位移测量及纳米定位。     

计量文摘精粹

1·纳米级电容测微系统的研究作者:于永新周涛郑义忠摘要:本文首先介绍了非接触式高精度电容测微仪的基本工作原理,进而详细论述了纳米级电容测微技术中所涉及到的非线性误差、环境噪声等关键技术问题,对典型驱动电缆方案作了比较。根据原理模型,给出了仪器的主要结构。对仪器自身产生的各种误差进行了详细的分析,并提出了相应的消除或修正方法。换用不同有效直径的传感器可以使仪器分辨力达到0·1nm,测量范围±2~±50μm,满量程非线性优于0·5%。该仪器可广泛应用于通过串口、USB口通信的高精度动、静态微位移测量及纳米定位。关键词:纳…     

临界角法探焦静态特性实验研究

临界角法探焦分辨力高、动态范围适中、结构简单、系统调试容易。采用临界角棱镜、光电探测器等器件组成光路得到离焦信号便可计算出离焦量。实验采用单光路临界角法 ,用四象限探测器探测输出信号 ,物面微位移采用压电陶瓷作为驱动元件。通过对离焦误差信号FES的分析 ,得出临界角法探焦静态分辨力优于0 0 2 μm、线性范围可达± 4 5 μm。     

角位移传感器校准方法的探讨

介绍了角位移传感器的分类及技术指标,提出了角位移传感器静态技术指标灵敏度、线性度、回程误差、重复性、零位电压和相位移等参数的校准方法和计算公式,通过对角位移传感器的校准保障了角位移传感器的各项技术参数满足预期的技术要求.     

机械天平的计量性能分析及故障处理

正一、天平灵敏性分析及相关处理措施1.灵敏性天平对不同物品重量所做出的反应就是灵敏度量值,这种量值的测定根据平衡原理进行。首先在天平的一端放上砝码,另一端放上物品,当天平处于平衡状态时,则所计量的物体重量就会清晰地表示出来,也就是将天平砝码的质量作为该物品的实际重量。另外,天平在空载和全载环境下所呈现的灵敏度是完全不同的。这是由于天平的线位移和角位移发生     

天平的灵敏度及其調整

天平的灵敏度是指天平指针在标牌上的线位移或角位移与在某一盘中所加的小重物的质量之比。即E=n/g 式中E——天平的灵敏度;n——指针尖端沿着标牌移动的分度数     

调焦光路中超精密双等位环平板电容位移传感器研究

在应用共焦显微镜原理实现对超精加工表面的几何量测量中,设计了一种环状的电容位移传感器,对物镜的调焦位移进行测量,使测量光轴从极板的中心孔穿过,测量位移方向与光路的光轴重合,与阿贝原理相符;采用微机电系统(MEMS)工艺加工双等位环电容极板,电容器极板很薄,间隙小于2μm,减小边缘效应附加电容,从而极大地提高了测量的线性和测量精度.设计了处理电路,对该传感器进行了标定,在0～30μm内,其线性度为0.05%,分辨力优于0.01μm.     

基于自抗扰控制算法的麦克斯韦快刀伺服控制系统

使用麦克斯韦力驱动的快速伺服刀具加工自由曲面,可以获得表面质量更优的加工效果.在快刀控制系统中引入适当的控制方式能够改善快刀的频响性能.本文针对麦克斯韦快刀,搭建包括软硬件在内的控制系统,硬件控制结构采用FPGA+DSP嵌入式控制架构,并加入自抗扰先进控制算法实现系统良好的抗干扰性能.为验证闭环控制系统性能,在自主搭建的精密位移测试平台进行系统位移分辨力和闭环带宽的测试,测试结果表明系统位移分辨力为5 nm,对频率108 Hz、峰峰值16μm正弦信号的跟踪误差为0.136μm,对频率540 Hz、峰峰值16μm正弦信号的跟踪误差为0.094μm.快刀系统行程50μm,闭环带宽4 kHz.线下仿真加工实验验证了快刀系统对常规面型的加工能力.     

用于微纳米几何量尺寸测量的三维微接触式测头

为实现微纳尺度器件三维几何形貌测量及表征,基于电容和压阻原理,开发了两种三维微接触式测头。其中电容测头测量范围4.5μm,轴向分辨力和横向分辨力分别为10 nm和25 nm;压阻测头测量范围4.6μm,轴向分辨力和横向分辨力分别为5 nm和10 nm。两种测头均可集成到纳米测量机,实现微结构几何参数的测量。     

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.