一种采用热电器件的实用化双波长高精度光纤测温仪

介绍了一种利用钽酸锂热释电探测器的光纤比色测温仪。该仪器由光学接收系统、信号放大与处理系、统及显示系统三部分组成。从单个探测器的温度分辨率与波长的关系、仪器的测温灵敏度、相对测温灵敏度与波长和被测温度的关系以及大气对红外辐射的光谱透射特性等出发,优化设计了系统的工作波长;从光学器件的制作、温度的测量过程、温度的测量方法和电路的噪声分析等出发,分析了影响仪器测温精度的多种因素。     

手持式红外测温仪的研究设计

智能红外线测温仪是采用STC89C52RC新型单片机作为处理器。通过逐点分析的方式,即把物体一个局部区域的热辐射聚焦在单个探测器上,并通过已知物体的发射率,将辐射功率转化为温度。光学系统的任务是汇聚辐射体发出的红外辐射,使能量更加集中,经调制器把红外辐射调制成交变辐射,交变辐射输入到光电探测器中,光电探测器的关键部件是红外传感器,它的任务是把光信号转化为电信号,从光电探测器输出的电信号被送进信号放大器由电子线路进行处理,并按照仪器内的算法和目标发射率校正后转变为被测目标的温度值,最后由显示器给出被测物体的温度,可方便的对测量结果进行实时监控,从而实现远红外测温仪的自动化和智能化。     

基于比色原理的瞬态温度测试系统

针对传统瞬态温度测试中存在的破坏被测温度场分布、使用寿命短、响应速度低等问题,设计一种基于比色原理的瞬态温度测试系统。介绍系统的结构以及测温原理,为提高整个系统的易用性,对系统进行小型化设计。其中,对滤光片与两象限探测器进行一体化设计,利用单片机完成实验数据的处理以及结果的实时显示,最后对整个系统进行封装。由高温黑体炉对系统进行静态标定来获得系统的静态系数K。在实验室环境中,利用氢氧焰机加热靶体的方式模拟瞬态温度场。同时利用已标定过的比色测温系统以及红外测温仪Modline5测量瞬态温度,在600~1 200℃的测温范围内,两者的误差1%,可以满足瞬态温度测试的要求。     

辐射测温在钢铁工业中的应用及发射率对测量的影响

采用辅助吹气、侧面瞄准和底部瞄准3种辅助方法,并利用热电偶校正红外测温仪发射率的方法改进了测量钢板温度的辐射测温技术.研究结果表明:带氧化皮的钢板在1 μm附近的光谱发射率约为0.84,全波发射率约为0.85;若将工作波长为1 μm的红外测温仪的发射率设置在0.81～0.87之间,全辐射红外测温仪的发射率设置在0.83～0.87之间,则钢板在1 000 ℃时,单波长和全辐射红外测温仪因发射率波动而导致的测温偏差分别小于4 ℃和7.5 ℃.     

采用三段温度控制的高精度中温黑体炉

我们研制了一台高精度红外测温仪定标用黑体炉。实验表明,该炉黑体腔底测温不确定度为±0.8℃。除可用于定标红外测温仪外,还可用于工业黑体辐射源有效发射率及红外探测器灵敏度的标定。     

一种可同时测量发射率及温度的被动式测温系统

介绍了一种实用化实时测温系统.该系统采用了PIN硅光电二极管作光接收器件,由光学接收系统、信号放大与处理系统及显示系统三部分组成.从系统的相对测温灵敏度及探测器的温度分辨率与波长间的关系出发,结合大气对红外辐射的透射特性,确定了系统的工作波长;从系统的抗反射辐射能力出发,并结合探测器的最小可探测光功率要求,确定了系统的波长带宽.从辐射能P1、P2的测量不确定度出发,讨论了待测目标的发射率及温度的测量精度.结果表明,当λ=0.80 μm、△λ=20 nm时,在测温范围600～2 500℃内,系统的测温不确定度优于0.3%,满足设计要求.     

红外测温系统在航空发动机轮盘试验中的应用

该文论述了红外测温基本理论和红外测温仪工作原理,设计开发了适用于航空发动机轮盘试验的非接触红外测温系统,分析影响红外测温系统测量准确度的主要因素,研究发射率的确定方法,在轮盘静止和旋转状态下进行了试验验证。其结果表明:影响红外测温系统测量准确度最重要的因素是发射率;用热电偶对发射率进行确定的方法是可行的;轮盘在静止和旋转状态下的发射率相同,静止状态下确定的发射率可用于旋转状态下的温度测量。     

影响红外测温的主要因素分析研究

红外测温在钢铁企业应用越来越广泛，成为钢企温度在线测量的关键设备。但在实际工作中，红外测温受到诸多因素影响，导致测温不准，影响产品质量控制。文章通过自主实验研究影响红外测温准确度最重要的发射率参数以及使用中安装距离等问题，综合确定几种钢材最佳发射率约为0.96(测温仪型号C316),使实验的几种钢种测量精度均能达到测量值的0.25%+1 K,并通过距离实验表明，即使在测试距离符合距离系数(D:S)的前提下，不同距离测量误差可能不同。本实验装置和方法可以为三钢不同的钢种或其它材料提供发射率测试，对测温仪发射率进行标定。     

比色式光纤温度测量仪的研究

文章介绍了一种基于比色测温原理研制的光纤测温仪，分析了比色测温原理，推导了其数学模型。该测温仪以硅和铟镓砷(InGaAs)光电二极管作为温度敏感元件，通过使用单片机与DSP的主从模式对两路互为参考的信号进行比值运算处理和控制，使仪器具有响应快，灵敏度高，重复性好等特点。文中论述实现上述特点的关键技术，通过样机实验给出性能指标和测量结果。     

红外测温仪测量准确度的影响因素分析及修正方法

从红外测温原理出发,介绍了红外测温仪的构成与特点,分析了环境、发射率以及距离等因素对其测量准确度的影响。通过采用实验数据拟合曲线对测温结果进行修正的方法,重点分析了距离因素对红外测温仪测量准确度的影响。其中以有效测温距离作为分界点,分段得到了拟合曲线与修正公式。实验结果表明,此方法能够有效提高红外测温仪测量结果的准确度,具有较高的实际使用价值。     

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.     

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...     

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.     

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.……     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

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.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

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.……     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.