对向靶溅射制备NiCr—NiSi薄膜热电偶的动态特性研究

用对向靶溅射制备了ＮｉＣｒ－ＮｉＳｉ薄膜热电偶，实现了薄膜民分与靶材基本一致。对热电偶进行动态特性测试表明，薄膜热电偶的时间常数τ随膜厚变薄而减小，并对此进行讨论。     

基于多项式插值的薄膜热电偶热电特性曲线拟合方法

针对薄膜热电偶热电特性曲线拟合大多采用基于最小二乘法的多项式拟合，这种方法单一，精度低的问题，文章设计了一种基于更高阶多项式插值的薄膜热电偶热电特性曲线拟合方法，并与拉格朗日插值进行了比较，解决了拟合方法单一且拟合精度低的问题。首先，对薄膜热电偶检定校准关键结构进行了介绍，搭建了薄膜热电偶检定校准平台；其次，对薄膜热电偶检定校准平台工作原理进行阐述，测取了薄膜热电偶固定点的热电势；最后，设计了一种阶数更高的使用三次样条插值的薄膜热电偶曲线拟合方法，并分别使用文章设计的插值方法与拉格朗日插值获得了热电曲线和一些非检定的热电势，计算出实测值与模拟值的残差平方和，得出了三次样条插值及拉格朗日插值的残差平方和分别为0.003 919 61和0.003 929 17,发现采用三次样条插值的拟合精度更高。     

薄膜热电偶热电特性分析与试验

薄膜热电偶具有体积小、操作简便、准确度高等优点,在精确测温领域显出了极大优势。采用磁控溅射法生产的热电偶在材料组合上几乎是无限的。本文对Ni CrNi Si薄膜热电偶、Ni Cr SiNi Si Mg薄膜热电偶静态下的重复性、使用寿命、温度上限等进行对比、分析,以便在使用中可以更好地"因地制宜"。与大连某高校制作的薄膜热电偶进行对比试验,验证制作工艺对薄膜热电偶性能的重要影响。薄膜热电偶作为一种新型热电偶,在发动机叶片等特殊部件表面测温领域具有广泛的应用前景。     

薄膜热电偶热电特性研究

薄膜热电偶厚度不超过15μm,能有效地保证不会对附着流的流谱或热流轨迹及壁厚产生扰动,可以显著地提高局部温度测量的精度。本文以镍基高温合金片为基底的薄膜热电偶为对象,简要介绍了薄膜热电偶的制备工艺;描述了薄膜热电偶的引线连接方法、不同引线方式的考核方法及结果;重点阐述其热电特性以及影响热电特性的关键因素;并对优化工艺条件下的薄膜热电偶的热电特性进行了验证。     

利用原位集成热电偶技术精准测量涡轮叶片表面高温温度的方法探究及误差分析

为实现航空发动机涡轮叶片表面高温温度的精准测量,首先需要对涡轮叶片表面薄膜热电偶进行精确校准,而校准误差主要起源于被校准热电偶与标准热电偶之间存在的温度迟豫。为此,该文在测试样品表面成功原位集成薄膜热电偶和铂点热电偶,进行高温重复循环试验,以铂点热电偶为校准基准,对多次重复循环的实验数据进行整体拟合,形成热电压与温度的校准曲线。并且对每一个测量数据进行误差分析,对校准误差范围形成有效的预估。结果表明:采用上述方法可以减少标准热电偶和被校准热电偶之间的温度迟豫,使涡轮叶片表面集成的薄膜热电偶校准相对误差可以有效地控制在±3%之内。     

T型柔性薄膜热电偶响应速度测试及其应用

比较分析T型柔性薄膜热电偶与传统热电偶丝在响应速度动态性能方面的差异,研究其对恒温金属浴温度偏差的校准方法。结果表明,T型柔性薄膜热电偶采用二维结构,相比传统一维结构的热电偶丝具有更高的稳定性和更快的响应速度,能够更好地对瞬变温度进行测量。在恒温金属浴温度校准测试中,T型柔性薄膜热电偶能更好地贴合于测试孔内,适应柔性曲面的测温需求,具有更高的测量准确度。     

薄膜热电偶的动态特性及动态补偿研究

针对用于瞬态高温测量薄膜热电偶的动态特性研究问题,本提出了为展宽其工作频带,以此来减小动态误差的方法。采用了一种脉冲激光法对薄膜热电偶进行了动态校准实验;利用基于沃尔什函数的建模方法建立了较好的薄膜热电偶动态模型;比一般的最小二乘法具有更高的拟合程度;通过地模型的极点和工作频带的分析,设计了动态补偿数字滤波器,改善薄膜热电偶的动态特性。     

薄膜热电偶的发展及其应用

重点介绍了采用阴极溅射法制取的铂－铂铑１０薄膜热电偶的最新高湿应用，包括制造工艺、高温绝缘以及试验和应用结果。同时还讨论了目前正在研制过程中的薄膜透明热电偶和耐蚀薄膜热电偶的有关问题。     

一种用于低温下瞬态测温的薄膜热偶技术

薄膜热电偶是采用高真空下离子溅射法制成的。从理论上对它的响应时间常数及动态测温误差进行了分析,并附有初步实验结果。从理论分析和实验结果看来,薄膜热电偶在低温下的响应要快于一般结点型热电偶。     

薄膜热电偶的分度方法和特性

为了试验并测定用真空蒸镀方法制取的集成电路基片温场的均匀性,用各种不同的材料制作了薄膜热电偶并对其进行了试验。用薄膜热电偶可以在不妨碍工艺过程进行的情况下局部测量表面任意一个需测点的温度。为了做到这一点,在被测物的表面需附着一个“热电偶网”。热电势值可用自动     

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 ...