提高不锈钢超高真空系统极限真空的一种方法

为提高超高真空系统的极限真空，在加热烘烤期间用干燥气体冲洗法进行了各种试验。结果表明：冲洗的比不冲洗的极限真空要好；间断冲洗的比连续冲洗的极限真空要好。这对如何提高真空系统的极限真空提供了一定实验依据。     

30管弹丸发射系统真空负荷及多级扩散

HL - 2A装置 30管弹丸发射系统选用了多级真空扩散室和 2种导管相集合的方式 ,以限制发射弹丸时推进剂进入放电真空室。这一设计主要取决于弹丸发射过程中推进剂的用量 ,并满足HL - 2A从装置外侧(低磁场侧 )及内侧 (高磁场侧 )加料时物理实验的需要。最后介绍了根据推进剂用量确定的真空负荷、导管结构和抽气机组     

真空太阳能集热管烘烤排气高真空系统设计

试验证明X50烘烤排气台的抽真空性能明显优于X35烘烤排气台的抽真空性能。在装载集热管加热烘烤结束时,X35排气台和X50排气台的高阀处的真空度接近相等,为2×10-3Pa;在真空管道端部处的真空度,X50排气台的真空度为5×10-3Pa,X35排气台的真空度为1.7×10-2Pa,明显差于高阀处。根据流导计算和试验结果分析,设计的真空太阳能集热管烘烤排气台的高真空系统,提高了装集热管真空管道边缘处的真空度,缩短了装集热管真空管道边缘处的空恢时间,提高了装集热管真空管道边缘处的极限真空度,并能应急处理抽气时集热管炸裂的情况,最终提高真空太阳能集热管的使用寿命。     

HL-2A托卡马克真空烘烤除气性能研究

120℃过热水循环系统对HL-2A主机真空室进行烘烤除气,温升梯度为±1.5℃,持续时间302 h。烘烤过程包含两个恒温阶段,90℃热平衡后真空度达到4.8×10-4Pa,120℃热平衡后真空度达到2.3×10-4Pa。真空室经过烘烤除气后真空度为2.2×10-5Pa。结合实验数据,通过拟合函数建立数学模型对真空度变化规律进行趋势分析,验证了过热水烘烤除气在HL-2A装置真空系统运行中的合理性和重要性,为300℃以上高温烘烤除气方案的制定提供依据。     

光阴极直流高压电子枪的极高真空系统

设计了一套用于光阴极直流高压电子枪的极高真空系统。首先对电子枪真空腔室的钛阳极、阴极和高压陶瓷分别进行表面处理及烘烤除气后确定材料表面放气率,然后对真空室压强进行模拟计算并确定配泵方案,最后在现场组装、检漏后对真空系统进行调试。调试过程中为了保证不能被直接加热的内部阴极杆在烘烤时充分除气,使用ANSYS-Fluent软件的S2S辐射模型对烘烤过程进行模拟并确定烘烤温度与时间。经过真空调试,电子枪腔内真空度为5.6×10~(-10)Pa,满足其极高真空设计要求。     

利用材料发射率来确定玻璃高真空系统的烘烤温度

在高真空系统中，真空室的烘烤温度对获得要求的真空氛围有着重要的影响，对于玻璃制作的真空系统，目前对于该温度的确定缺少一种较为简单易行的方法，本文基于辐射换热分析提出了具有通用性的利用材料表面辐射率来计算玻璃表面烘烤温度的近似方法，将这难以直接测量的温度通过附设热电偶的示值和本文推荐的关系式来确定，于实际情况相比较为吻合．     

有油排气系统的改进

以普通油扩散泵一机械泵组成的有油排气系统是当前电真空器件生产中获得高真空的重要手段。由于目前电真空器件在该有油排气系统上排气封离时极限真空都限制在１０－７～１０－６乇，且存在油蒸汽对被抽器件的污染，使许多要求耐高压、高放射率和长寿命的器件的性能不能稳定和提高。 本文试验了由钛升华阱──冷阱──普通扩散泵──活性氧化铝吸附阱－机械泵组成的真空系统的抽气性能。结果表明系统极限真空度用液氮冷却在五～八小时内达到 （５～８） × １０－１０乇，自然冷却达到（３～４） × １０－９乇。并用该试验系统试排了数只 ＴＭ－８５电子管，在基本上不改变原排气工艺规范和不延长排气时间的条件下封离时真空度为 （１～２） × １０－８乇比原系统提高了二个数量级，参数全部合格，试验结果说明，系统的操作步骤对极限真空有很大影响，如在管内采用锆铝吸气剂并适当改变排气工艺规范以适应系统的超高真空性能可能获得更高的极限真空度。     

论不锈钢容器中烘烤对出气率与抽速关系的影响

为了研究真空系统中烘烤时对出气率与抽速关系的影响，在室温条件下未经烘烤和在室温条件下经过温度为１００℃和２５０℃烘烤的情况下，对出气率与抽速的关系进行了测量。测量所得出气率ｑ（Ｔｏｒｒ，ｌ／ｓ，ｃｍ＾２）遵循指数规律：ｑ＝（Ｃｓ／Ａ）＾ｍ，其中，ｃ和ｍ（０〈ｍ〈１）为常数：Ｓ／Ａ为抽气参数，其定义为抽速Ｓ（ｌ／ｓ）与真空容器表面积Ａ（ｃｍ＾２）之比，Ｓ／Ａ的变化范围从２．４６×１０＾－５到１．２６     

充入气体含水量对超高真空系统排气特性的影响

在未烘烤的超高真空系统中，真空室表面所吸附的水蒸汽是影响排气时间及极限真空度的关键因素。通过实验，对充气气体中水蒸汽含量及操作方式与真空系统排气特性的关系进行了测试，为超高真空系统操作工艺的确定提供了依据。     

HL-2A装置器壁处理质谱分析

为了对HL-2A装置升级改造后的器壁处理效果展开分析，使用四极质谱计对HL-2A装置壁处理过程中或壁处理前后的残余气体进行了质谱测量。利用粒子平衡方程和质谱图变化分析了直流辉光放电清洗过程中的气体成分变化。研究了HL-2A装置壁处理的性能并优化了He+D₂-GDC的氦氘比例参数。结果表明：HL-2A装置真空室烘烤除气后，残余气体中H₂O所占百分比由烘烤前的92%降至56%，真空室真空度达到2.2×10^-5Pa；在不同阶段利用H₂-GDC、He-GDC、He+D₂-GDC进行壁处理消除了真空室内部件升级改造对壁处理造成的不利影响，保障了HL-2A装置等离子体放电实验的开展。     

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.     

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.     

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.     

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.     

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