虚拟仪器在液压动力系统压力测试中的应用

利用基于图形化的编程语言LabVIEW搭建了液压系统压力测试平台,使用多种压力传感器对溢流阀启动和延时关闭过程中系统压力进行测量.结果表明,LabVIEW在信号测试中能够快速的建立起测试平台,使用起来简单方便并能准确的对信号进行采集和分析;压电式压力传感器的动特性好,适于对瞬时变化的信号测量,电阻应变式压力传感器适于稳态信号的测量,但从安装方式和测试成本来看,电阻应变计更适合液压设备动态压力信号现场监测.     

采用光纤传感器的电子塞规的设计

针对内孔零件批量快捷测量的问题，提出了基于反射式光强调制型光纤位移传感器的电子塞规测试系统。介绍了系统的测量原理与机械结构，设计了光纤位移传感器的结构和补偿算法。     

轨道车辆动态限界测试系统设计

针对传统轨道车辆限界测试不能实时、连续、快速获得车辆限界的不足,提出一种车辆限界自动化测试系统。该系统根据车辆限界标准及测试要求,结合车辆结构和车辆相对于轨道位置变化的特点,通过在车体及转向架上布置测量传感器,测量车辆相对于轨道的位移和偏转角度,然后提出一种算法对传感器输出数据进行处理,完成轨道车辆的动态轮廓线的实时计算,并在车辆行驶过程中叠加生成车辆最大动态轮廓边界。同时测试过程中通过车辆的动态轮廓与标准限界的实时比较,实现对车辆限界的监测与校核。实车对比试验表明,传统方法测试的车辆轮廓与该测试系统测试结果误差范围在1%以内,该测试系统能够准确测量车辆轮廓线,并在车辆运行过程中实现车辆限界的在线、实时、连续测试。     

感应式微小位移传感器测量方法研究——标准载波信号和标准量块的结合测量

一、前言在当今测试领域,跨项目交互测量、综合测量已成为计量行业中的发展方向。本文阐述的就是利用电子测试中的载波信号和长度测试中的标准量块所搭建的测试平台,对感应式微小位移传感器进行的位移量标定。整个测试系统包括了两个方面:(1)正弦波载波信号通过标准信号发生器输入至传感器电桥的输入引线上,通过电桥电路把信号再传输至电桥的输出引线上,继而再传输至高精度数字多用表上进行电     

4H-SiC MEMS高温电容式压力敏感元件设计

为了研制Si C高温电容式MEMS压力敏感元件以满足高温环境下压力参数测量,设计了一种基于P型4H-Si C减薄抛光工艺制备高温变间隙电容式压力传感器敏感元件结构方法;通过数值仿真,研究了敏感元件的性能,得到敏感元件输出电容随压力、温度的变化曲线;通过微机械加工工艺制备出了Si C电容式高温压力传感器敏感元件,研制出Si C电容式高温压力传感器原理样机,通过模拟高温压力传感器样机工作环境,搭建了高温微压测试平台并对原理样机进行性能测试;结果显示,样机在873.15 K下能够正常工作,灵敏度为18.7 f F/k Pa,非线性为12.60%,迟滞为0.47%,能够满足解调电路拾取压力信号.     

非规则物体位移的测量

在测量非规则物体位移时，研制了一种新型位移传感器──滚动光栅位移传感器。它能在线测量一些特殊的长度量（如线位移、非圆物体的周长、眼镜镜片的当量直径等）。文章较为详细地对该传感器结构作了介绍，并通过测试和检验证明该传感器能达到较高的测量精度。     

非规则物体位移的测量

在测量非规则物体位移时，研制了一种新型位移传感器－滚动光栅位移传感器。它能在线测量一些特殊的长度量。文章较为详细地对该传感器结构作了介绍，并通过测试和检验证明该传感器能达到较高的测量精度。     

压捆机压缩特性测试方法的分析

为研究牧草、秸杆等物料的压缩特性，以9KG350型高密度压捆机为试验装置，根据该机的结构特点和压缩特性的基本参数选用了压力传感器和位移传感器，着重介绍了其测试原理和方法，并通过试验结果表明了该测试系统的性能和可靠性。     

电阻应变式传感器及其在多个力传感器测试技术中的运用

电阻应变式传感器由弹性敏感元件和电阻应变片组成。将电阻应变片安装在弹性敏感元件上 ,当弹性敏感元件在感受被测量时会导致其表面出现变形 ,即应变 ,致使其表面所附的电阻应变片随着产生应变 ,通过测量此时电阻应变片的电阻值的变化 ,可以测量位移、加速度、力、力矩、压力等各种参数。在此 ,为读者介绍一种电阻应变式传感器在多个力传感器测试技术中的应用例子。在实际测试过程中 ,常常会出现多个力传感器共同实现对一个力负荷进行测试的情况 ,每一个力传感器将会产生一个测试输出信号 ,因此 ,需要将各个力传感器的输出信号相加 ,得到总…     

微波叶尖间隙测量传感器的计算分析

介绍了利用微波相位法测量短距离位移的工作原理,建立了一种基于此原理的谐振腔结构微波传感器模型,并完成了模拟计算。分析了微波传感器测量发动机叶尖间隙的能力,和高温环境对传感器性能的影响。结果显示此传感器能够在高温环境下完成0~6 mm范围内的高精度位移测量,可以很好的应用于航空发动机叶尖间隙的测试。     

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 ...