钒酸锶(Sr2V2O7)氧敏电阻特性的研究

通过钒酸锶电阻特性的研究，评估其作为电阻型氧敏传感器的可能性．实验中测量了不同温度下钒酸锶陶瓷片的体电阻和不同温度、不同氧压下的表面电阻，对实验数据进行数学处理后，得到钒酸锶材料的一些性质：相变对其电阻特性的影响很小；体电阻和面电阻的激活能分别为1．31eV和191eV；表面电阻的氧敏因子m＝6；温度系数相对较大．所以钒酸锶要作为尾气传感器材料，需考虑进行表面改性．     

电阻应变式传感器线损补偿电路设计

当二次测量仪表与传感器有一定距离时，由于桥路供电导线自身电阻的存在，且导线的阻值随环境温度而变，这将不可避免地引入测量误差。文中提出了供桥电压直接补偿法和比率补偿法。前者是将采样线反送回的实际桥压信号与供桥电压源的基准电压进行比较，通过误差放大器控制调整管，使加到传感器测量桥路上的电压保持稳定；后者是通过电路进行比率运算，消除桥压对测量结果的影响。在采用A/D变换技术的测量电路中，应用比率法不仅能有效的消除桥压变化对测量结果的影响，而且在电路上也非常简单。     

燃油流量高精度计量的研究

分析了涡轮流量传感器的工作原理。研究了由于燃油的温度变化引起的传感器本身尺寸变化、燃油密度变化给计量精度带来的影响。在温度、压力可调整的燃油实验装置上对传感器进行了实验研究。发现可以用线性公式来描述质量仪表系数随温度变化的规律；质量仪表系数的绝对变化量、相对变化量可近似为恒定值。提出了两种温度补偿方法，可分别得到优于0．2％和优于0．25％的质量流量计量精度。     

接地导通电阻测试仪电阻示值误差分析

JJG984—2004《接地导通电阻测试仪》国家检定规程和JJF1059-1999《测量不确定度评定与表示》国家技术规范的要求，以MG11D接地导通电阻测试仪为例，通过采用不确定度A类和B类评定方法，对接地导通电阻测试仪电阻示值误差的测量结果不确定度进行了定性分析和定量分析。得出符合检定规程的要求的结论。     

光纤布拉格光栅应变传感器的低温特性

研制了一种新颖的菱形光纤布拉格光栅（FBG）低温传感器。采用有限元方法分析了这种结构的力学性能和温度特性。将该装置置于低温（液氮）拉伸设备中，实验研究了这种封装形式的低温应变特性。采用光纤布拉格光栅网络分析仪和低温应变仪，分别测量了液氮温度下菱形应变传感器的波长变化量和应变变化值，测得其应变系数为-0．7185μe／pm，线性度达到0．9998。     

青岛艾诺电子仪器有限公司

艾诺仪器公司成立于1993年，专业研发生产仪器仪表、设备，提供各类行业测试和供电解决方案。主要产品有数字安规、智能电源、LCR电桥、电性能测量、行业专用测试等多个系列。智能安规系列，包含耐压、接地导通电阻、绝缘电阻、泄漏电流测试仪、安规综合测试仪和耐电压测试仪校验；智能电源系列，包含工业变频电源、军用航空中频电源、EPS应急电源、28V直流电源、特种测试电源、工业不问断电源；     

新型多孔介质局部含湿量测试仪的研究

采用针型电容测湿传感器和单片微处理机技术研制成一种新型多孔介质局部含湿量测试仪。本文论述该测试仪的组成、工作原理和硬、软件结构及其特点。实验结果表明，可望满足多孔介质局部含湿量测量的实用要求。     

关于请作者提供身份证号码及其他个人基础信息的启事

一、工作原理 PTB220感应元件采用VISALA研制的硅电容绝对压力传感器BAROCAP，是通过硅微加工而成。PTB220的工作原理是基于一个先进的RC振荡电路和三个参考电容，并且电容压力传感器及电容温度传感器连续测量，微处理器自动进行压力线性补偿及温度补偿。当得到压力变化时．硅薄膜弯曲使传感器真空室高度发生变化，导致传感器电容值发生变化。通过测量转换，可以得到压力值。     

电主轴偏摆测试仪校准装置的研制

电主轴偏摆测试仪是用来测量主轴高速旋转状态下偏摆量的测量仪器,研究如何计量校准高速电主轴偏摆测试仪,从而保障电主轴偏摆测试仪的量值溯源非常有意义。文章提出采用非接触式测量模式对高速电主轴某一运动状态进行偏摆量的测量标定,利用高精度激光位移传感器高频率响应对高速运行的电主轴采样测量主轴偏摆量,标定电主轴偏摆量值,再对主轴偏摆测试仪进行校准,达到量值溯源目的。     

低温用简便温度程序控制器

DP-J型低温膨胀仪和电阻测试仪是连续自动记录温度—膨胀量曲线和温度—电阻变化量曲线的仪器,它的炉温要求程序控制,实现线性地升降温或阶梯形升降温程序。为此,我们研制了低温简便温度程序控制器。该控制器用于DP-J型低温热膨胀仪(4.2K-300K)和电阻测试仪(77K-600K),实现恒速升降温和阶梯形的升降温。升降温的速率可在0.5℃～50℃/分范围内任意选择,恒温控制精度不低     

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.……     

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.     

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 ...