反应磁控溅射制备的SiO2防护涂层抗原子氧侵蚀性能研究

在原子氧侵蚀地面模拟设备中对Kapton和利用反应磁控溅射制备的SiO2涂层进行了原子氧暴露实验，并采用XPS和SEM等分析手段对暴露前后试样表面的物理和化学变化进行了研究．结果表明，Kapton试样遭受了严重的侵蚀，质量损失较大；SiO2涂层质量变化很小，对基体提供了良好的保护作用．XPS分析结果表明，反应溅射的SiO2涂层是富Si的，初始暴露时由于氧化反应而质量有少许增加，随时间延长，涂层变得完全符合化学计量．SiO2涂层在原子氧暴露后涂层的太阳吸收率、辐射率和反射系数均没有发生明显的变化．SiO2涂层较脆，易产生裂纹，原子氧会通过缺陷位侵蚀下面的基体材料，严重影响飞行任务的正常进行。     

金属基表面Al2O3-SiO2涂层耐冲蚀性能的研究

结合炼钢转炉用风机因炉气而导致叶片磨蚀较快的实际情况，从改善叶片材料的角度出发，采用溶胶-凝胶法制备Al2O3-SiO2涂层用在金属基体上进行试验。结果表明在含3％（质量分数）Si02磨粒的水介质中，单一三层的SiO2涂层、SiO2-Al2O3-SiO2涂层及混合溶胶制备的复合涂层的耐冲蚀性相近，均比单一三层的Al2O3涂层及A12O3-Sio2-Al2O3涂层好。混合溶胶制备的复合涂层在3％（质量分数）SiO2磨粒的酸性介质中表现出了良好的耐冲蚀性。     

聚丙烯酸酯/纳米SiO2织物涂层整理剂的性能

采用溶胶-凝胶法制备SiO2溶胶,将其与聚丙烯酸酯乳液进行复合制备聚丙烯酸酯/纳米SiO2复合乳液,并将其用于织物的涂层整理。采用动态激光光散射(DLS)和透射电镜(TEM)对乳液进行了表征,考察了SiO2溶胶对复合乳液性能以及应用后织物防水透湿性能的影响。结果表明,乳胶粒与SiO2溶胶粒径在100 nm～120 nm,溶胶在乳液中分布均匀;SiO2的引入及均匀分散使成膜的断裂强力提高2倍,断裂伸长率提高6.3%,吸水率基本不变;当上胶量为71g/m2左右时,SiO2溶胶的加入会使涂层的防水性能提高,且透湿量基本不变。     

Ba_(0.5)Sr_(0.5)Al_2Si_2O_8-Y_2Si2_O_7体系环境屏障涂层的制备与抗水氧腐蚀性能表征

采用溶胶-凝胶法合成了Ba0.5Sr0.5Al2Si2O8(BSAS)-Y2Si2O7粉体,并以2DCf/SiC为基体,采用浆料涂覆工艺在其表面制备了BSAS-Y2Si2O7环境屏障涂层,表征了涂覆与未涂覆BSAS-Y2Si2O7涂层Cf/SiC复合材料的抗水氧腐蚀性能。结果表明:在高纯氩气保护下,经1450℃高温烧结3h,可在Cf/SiC试样表面制备致密的BSASY2Si2O7涂层;在1250℃、50%H2O-50%O2、常压静态气氛下腐蚀200h后,涂覆BSAS-Y2Si2O7涂层的Cf/SiC试样的质量基本不变,基体中的纤维得到了很好的保护,所制备的BSAS-Y2Si2O7涂层具有较好的抗水氧腐蚀性能;同时,BSAS-Y2Si2O7涂层也表现出裂纹自愈合能力;与之相比,未涂覆BSAS-Y2Si2O7涂层的Cf/SiC试样的失重较为明显,基体中的纤维已经完全被水氧环境所侵蚀。     

空间级硅橡胶涂层抗原子氧性能及评价机制

文中针对硅橡胶与原子氧的反应机理尚未完全掌握,其防护效果未完全明确的现状,开展原子氧效应地面模拟试验,进行硅橡胶涂层的抗原子氧性能的评价分析。经对试验前后的样品进行外观、质量损失、表观形貌、表面成分及光学性能的测试,系统评价了空间级硅橡胶的原子氧防护效果。在分别接受累积通量为4.9×10~(18) cm~(-2)和1.2×10~(21) cm~(-2)的原子氧暴露试验后,空间级硅橡胶涂层的质量损失并未随原子氧暴露时间延长和累计通量的增加而变大,但涂层表面的外观和光学性能发生了显著变化,经扫描电镜检测,涂层表面出现不同程度的开裂,经X射线光电子能谱仪分析,涂层表面生成了一层类似SiO_2的薄膜,该薄膜层能阻止原子氧与硅橡胶涂层的反应从而对基底材料形成保护,但为了进一步提高其抗原子氧侵蚀能力,需对涂层进行补强改性,并且采用测量质量损失的手段来评判硅橡胶类材料受原子氧侵蚀程度的方法不甚科学。     

含TiO_2/SiO_2的复合涂层光活性和抗老化性能

以钛酸四丁酯、正硅酸乙酯为前驱体,用溶胶-凝胶法制备了纳米TiO2/SiO2复合物。并将其分散到醇酸树脂中制成含TiO2/SiO2的有机涂层。实验结果表明,TiO2/SiO2复合粒子比纯TiO2粒子拥有更强的光催化性能,含TiO2/SiO2的有机涂层比只含有TiO2的有机涂层具有更好的抗老化性能。     

溶胶-凝胶法制备无机纳米/聚酰亚胺杂化膜及其表征

采用溶胶-凝胶法制备了SiO2及A12O3溶胶,并将其掺入到聚酰胺酸基体中,得到无机纳米SiO2-Al2O3/聚酰亚胺杂化膜,并对其结构性能进行了研究.实验表明,薄膜材料中无机纳米SiO2和Al2O3粒子分散均匀,与有机相存在键合;材料热分解温度有所提高.     

用溶胶-凝胶法制备保护涂层的研究进展

溶胶-凝胶(Sol-gel)法用于金属及合金表面制备保护涂层可明显提高材料在各种环境下的耐蚀性、抗高温氧化性、耐磨性等性能,从而扩大金属及其合金的应用范围.介绍了Sol-gel涂层的制备技术、涂覆工艺以及涂层热处理的一般原理及特点,总结了该技术制备保护涂层的应用现状及最新研究进展,讨论了制备单组分氧化物涂层如ZrO2涂层、SiO2涂层、CeO2涂层、Al2O3涂层、TiO2涂层,双组分氧化物涂层如ZrO2-CeO2涂层、SiO2-ZrO2涂层以及多组分氧化物涂层的制备方法及涂层对基体材料的保护作用,并对其保护机理进行了初步探讨.     

Al3+-SiO2共掺杂TiO2光催化膜的制备及超亲水改性

为了提高TiO2光催化薄膜的利用效率,实验采用金属离子Al3+和氧化物SiO2共掺杂的方法,制备以TiO2为基体的复合光催化薄膜.利用简单易行的溶胶-凝胶法结合超声分散技术以两种不同的方式,一种是同步将Al3+和SiO2共掺杂于TiO2溶胶中,制备多元素共掺杂混合溶胶,采用浸渍提拉的方法以玻璃片为载体涂膜,然后运用马弗...     

聚酰亚胺/SiO_2纳米复合抗原子氧气凝胶的合成与性能

以3,3′,4,4′-联苯四酸二酐(sBPDA)和2,2′-二甲基-4,4′-二氨基联苯胺(DMBZ)为聚合单体,八(氨基苯基)聚倍半硅氧烷(OAPS)为交联剂,SiO2纳米粒子为填料,采用超临界二氧化碳干燥工艺制备了一系列聚酰亚胺(PI)/SiO2纳米复合气凝胶(CPIA-SiO2-0~CPIA-SiO2-7)。研究表明:SiO2纳米粒子的引入对PI气凝胶的耐热性能未产生显著的影响。然而,随着SiO2纳米粒子含量的增加,PI气凝胶的孔隙率从89.6%逐渐降低至79.4%,BET表面积也随之从425.5m2/g降低至380.2m2/g,纳米泡孔孔径分布呈现出变宽的趋势。SiO2的引入显著提高了PI气凝胶的抗原子氧侵蚀能力,含量为7%(质量分数,下同)的PI/SiO2复合气凝胶CPIA-SiO2-7的原子氧侵蚀率(2.6%)仅为不含SiO2气凝胶CPIA-SiO2-0的原子氧侵蚀率(12.3%)的1/5左右。     

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.……     

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.     

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...     

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.……     

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.     

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.     

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 ...