低成本简易型紫外成像装置设计

受限于进口紫外成像设备的知识产权和昂贵的价格,高压电器绝缘故障检测设备缺乏。为解决该问题,设计一种基于STM32的低成本简易型紫外成像装置。该文基于紫外光谱特性和电晕放电检测机理,完成简易嵌入式紫外成像装置的总体硬件设计和软件设计。重点介绍紫外传感器的选型和高压驱动电路设计,并建立仿真模型对紫外采集电路进行验证。采用GPS/北斗双模定位系统,准确定位电晕放电位置。通过不同光源及距离下对表征紫外强度脉冲宽度进行测试,验证该装置测量紫外强度的有效性。     

"日盲"紫外电晕探测系统定标

"日盲"紫外电晕探测是电力设备检修与维护的主要手段之一.为了提供更为准确和客观的评价依据,需要对"日盲"紫外电晕探测系统进行辐亮度定标,从而确定目标辐亮度与增益控制电压、系统输出灰度值之间的关系.为此构建了由高稳定氘灯光源、积分球、光纤光谱仪等组成的定标装置.采用可溯源美国NIST的紫外标准氘灯对光纤光谱仪进行光谱辐照度标定,并以光纤光谱仪作为标准探测器对电晕探测系统进行定标.通过实验拟合出ICCD增益控制电压与系统增益之间的关系曲线,并给出了系统的标定方程.随后进行了三组不同增益的验证实验,实验结果表明在线性区内辐亮度推算值与测量值之间的最大相对误差为6.11%,均方根为3.22%.经分析,文中所采用的系统定标方案的不确定度为9.1%,基本可以满足了"日盲"紫外电晕探测系统的需求.此外,不同增益条件下的系统响应特性可以为"电晕"探测过程中进行自动增益调整算法的设计提供参考依据.     

日盲型紫外探测系统的探测距离模型及实验研究

日盲区的存在,给近地探测240～280 nm范围的紫外辐射提供了良好的背景.本文设计了一套成像型日盲紫外探测实验系统.从辐射能量传递的角度出发,借鉴凝视型红外搜索跟踪系统的分析方法,推导了紫外探测系统的探测距离模型.以氘灯为探测目标,在三种典型天气条件下对实验系统进行了探测距离实验.结果表明,采用探测距离模型的计算值和实验测量值有较好的吻合,为紫外探测系统的设计和性能评估提供了重要的理论和实验基础.     

新型高分辨率紫外-可见成像光谱仪波长定标系统设计

限于常规波长定标的局限性,构建了高分辨率紫外-可见成像光谱仪波长定标装置.该系统主要由具有高稳定性的300W氙灯系统、前置施瓦兹型聚光镜、高光谱分辨力的中阶梯光栅单色仪以及后置光学系统组成.利用ZEMAX光学设计软件,对该中阶梯光栅单色仪光学系统进行了优化设计.对设计结果进行了分析,设计结果表明,所设计的高分辨率紫外-可见成像光谱仪波长定标装置满足设计指标要求,扫描光谱范围270～500 nm,光谱分辨力小于0.05 nm,波长精度小于0.05 nm.     

紫外序列图像中目标的提取

分析了"日盲"紫外ICCD(增强型电荷耦合装置)探测系统所采集紫外图像中噪声和目标的特点,基于紫外图像的特点,提出了一种紫外序列图像中目标提取的方法.该方法首先采用时域递归低通滤波算法对紫外图像进行降噪处理,有效抑制了图像中的随机噪声,提高了图像的对比度.然后运用自适应阈值分割算法对目标进行了提取.实验结果表明,该方法能较好地检测出紫外序列图像中的目标,具有较强的噪声抑制能力.     

CsI/Ni/LiF半透明真空紫外光阴极“日盲”效应的验证

CSI／Ni／LiF半透明真空紫外光阴极，由于CSI的长波阈值为200nm，即有很好的“日盲”效应。通过对照测试，得到验证。用氢真空紫外辐射源作检测光源，在专用的真空紫外光电发射特性测试系统中，测得CSI／Ni／LiF半透明真空紫外光阴极在105～165nm波长范围内平均量子产额为0．16～0．21电子／入射光子，而在200～365nm紫外辐射下，其量子产额仅为10－6～10－5电子／入射光子。可见对200nm以上波长的紫外光不灵敏，即具有良好的“日盲”效应。     

基于紫外检测技术电晕笼中的导线起晕电压研究

电晕笼是研究特高压交直流输电线路导线电晕的一种经济有效的手段,被广泛应用于特高压导线电晕特性的研究中。本文采用紫外检测技术对起晕电压进行判断,电晕放电会产生紫外线,会被紫外仪检测到,不会受到太阳光中紫外线的干扰,因此可用于输电线路和变电站设备局部放电的检测。实验中使用以色列产的DayCorII型紫外成像仪。采用紫外光子数,作为电晕放电的强度表示,从光子数量的变化上,来判断导线的起晕电压,同时配以图象辅助判断。     

248 nm紫外显微镜微纳线宽校准方法的研究

248 nm波长照明的紫外显微镜能够获得高达80 nm的光学分辨率,可以实现对掩模板的线宽和一维/二维栅格参数的测量。作为测量仪器的248 nm紫外显微镜需要对其进行校准。该显微镜测量范围在nm量级,校准使用400 nm一维栅格标准物质,通过对仪器不确定度和标准物质自身不确定度的评估,得到采集图像每个像素的扩展不确定度为0.178 nm,并给出了实际测量时的不确定度评价公式。     

基于阵列探测方式的时域光声成像系统

将阵列超声探头和超声相控技术与光声成像相结合的成像系统，与采用水听器的单探头旋转扫描光声成像系统相比，避免了机械旋转机构给光声信号采集所带来的不稳定性，提高了数据采集速度．时域光声信号由64阵元线阵超声探头以电子相控聚焦的方式进行线性扫描采集，然后通过时域后向投影算法进行光声图像的重建．采用波长532nm、重复频率10Hz的脉冲激光，系统可快速重建样品内部光学吸收分部的二维图像，单帧图像数据采集时间小于200s，成像横向分辨率小于2mm．实验结果表明，采用此方法可显著提高系统对光声信号的扫描稳定性和成像效率，该系统是一种有潜在临床应用价值的光声成像系统．     

电晕探测中的紫外对焦控制系统

本文简要介绍了电晕探测的原理,采用可见光与紫外双光谱探测方法来检测电晕信号的存在并对其进行定位.文中介绍了电晕探测系统紫外对焦控制模块,并阐述了对焦的双闭环控制过程及其软硬件实现方法.分析了对焦控制过程中误差产生的原因,主要包括传动机构的空回及系统的过冲量.通过实验测量得到传动机构的空回和过冲量,将其加入紫外对焦过程的总对焦量.采用上述方法可以减小紫外对焦系统的对焦误差,使紫外相机像面始终处于焦深之内.最后,利用电晕探测系统对高压电厂中的电晕信号进行检测并定位.     

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.     

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.     

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.……     

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.     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.