热循环、真空紫外辐照对Al/Kapton薄膜的损伤效应

在空间环境地面模拟设备中模拟热循环、真空紫外辐照等低地球轨道空间环境对Al/Kapton薄膜的损伤效应.利用原子力显微镜、紫外可见分光光度计对试验前后试样的表面形貌、光学参数等性能进行了分析.结果表明,热循环、真空紫外辐照使Al/Kapton薄膜试样产生质量损失,表面形貌发生不同程度的改变,在紫外可见波段的反射率下降明显.     

原子氧与紫外综合辐照对Kapton/Al性能的影响

Kapton/Al薄膜二次表面镜是一种广泛应用的热控涂层,用于维持航天器表面正常的工作温度。本文利用激光源原子氧设备对Kapton/Al薄膜二次表面镜进行了原子氧与紫外综合辐照试验,试验前后通过高精度微量天平、扫描电镜、紫外-可见-近红外分光光度计及X射线光电子能谱仪等测试分析手段观察了材料质量损失、表面形貌、光学性能随辐照时间的演化规律,分析了试验前后Kapton/Al薄膜二次表面镜表面成份的变化。结果表明:Kapton/Al薄膜二次表面镜的质量损失随辐照时间的增加呈线性增大,原子氧与紫外综合辐照造成的质量损失明显高于单独原子氧作用产生的质量损失;试验后试样表面呈"地毯"状形貌,且随辐照时间的增加表面粗糙度变大;Kapton/Al薄膜二次表面镜的光谱反射系数随综合辐照时间的增加而降低,致使太阳吸收比的变化不断增大;试验后试样表面成份变化明显,说明原子氧和紫外环境与Kapton/Al薄膜二次表面镜表面发生了复杂的物理化学作用。     

典型低轨辐照环境对MoS2-Ti薄膜真空摩擦学性能的影响

采用非平衡磁控溅射方法在9Cr18基底上制备了MoS₂-Ti薄膜，并对4组样品分别进行了电子辐照、电子/质子辐照、电子/质子/紫外辐照、电子/质子/紫外/原子氧辐照。采用SEM、XRD、XPS分析了辐照前后薄膜的结构和化学组成变化，通过摩擦试验考察了辐照前后薄膜的摩擦学性能，探讨了其损伤机制。研究结果表明，电子辐照、质子辐照、紫外辐照对MoS₂-Ti薄膜的显微组织结构、表面形貌及摩擦学性能没有明显影响。动能5 eV的原子氧对MoS₂-Ti薄膜表面有显著的损伤，主要表现在表面出现“绒毯”状形态，Mo、S和Ti元素被氧化成高价氧化物。原子氧辐照导致MoS₂-Ti薄膜摩擦起始和中段摩擦因数升高、中段摩擦因数不稳定，比磨损率增大。     

质子辐照对聚酰亚胺薄膜摩擦学性能的影响

采用流延法制备了聚酰亚胺(PI)薄膜，利用空间环境地面模拟设备，研究了空间环境中质子辐照对PI薄膜表面结构、化学组成和摩擦学性能的影响，探讨了质子辐照对材料的影响机理。结果表明：质子辐照导致PI分子链的结构发生了变化，PI薄膜表面发生了碳化反应，硬度与弹性模量显著提高，平均粗糙度降低。质子辐照改善了PI薄膜的摩擦磨损性能。     

空间电子作用对ZnO-有机硅热控涂层光学性能影响研究

研究了空间电子辐照作用下ZnO-有机硅热控涂层光学性能的变化规律.通过扫描电镜、原子力显微镜和电子能谱分析了电子辐照前后试样表面形貌和元素组成变化,探讨了电子辐照的损伤机理.试验结果表明,在相同能量情况下,随电子的辐照剂量的增加,有机硅热控涂层的表面硅树脂发生了降解,产生了碳化,因而导致了ZnO-有机硅热控涂层的光学性能下降.     

激光源原子氧对Kapton薄膜和Kapton／Al薄膜二次表面镜性能的影响

在模拟空间环境原子氧暴露条件下,采用激光源原子氧对热控涂层材料Kapton薄膜、Kapton/Al薄膜二次表面镜进行了不同剂量的暴露试验。研究了这两种材料的质量损失、表面形貌随原子氧暴露剂量的变化关系,以及Kapton薄膜的光谱透过率、Kapton/Al薄膜二次表面镜的光谱反射率和太阳吸收比Δαs随原子氧暴露剂量的演化规律。结果表明:两种材料的质量损失随原子氧暴露剂量的增加呈线性增大;原子氧暴露后,试样表面呈"地毯"状形貌,且随暴露剂量的增加粗糙度变大;Kapton薄膜的光谱透过率、Kapton/Al薄膜二次表面镜的光谱反射率随原子氧暴露剂量的增加而降低,Kapton/Al薄膜二次表面镜的太阳吸收比Δαs随暴露剂量的增加而增大。最后对Kapton薄膜的存在寿命和Kapton/Al薄膜二次表面镜绝热平面的平衡温度进行了预测。     

高能电子辐照对黑色聚酰亚胺薄膜结构的影响

借助双束加速器对黑色聚酰亚胺薄膜进行了高能电子辐照实验。分别通过SEM、ATR-FTIR及XPS考察了辐照前后黑色聚酰亚胺薄膜表面的形貌变化、表面化学结构与成分变化。结果表明,通过SEM观察发现,电子辐照后,黑色聚酰亚胺薄膜的表面变得更加粗糙。这可能是由于高能电子使PI/C表面上的弱键分解,从而改变了材料表面的结构,导致材料表面粗糙度增大。通过红外光谱分析发现,电子辐照后,PI/C表面大部分基团的吸收峰强度有所降低。这表明电子辐照使PI/C表面发生了复杂而显著的化学反应。其中黑色聚酰亚胺薄膜的吸收峰强度显著降低,表明材料在电子辐照过程中发生了开环反应。通过XPS分析发现,PI/C中的含氮量及含氧量显著降低,样品表层发生了脱氮及脱氧反应,也佐证了红外光谱表征中电子辐照可使黑色聚酰亚胺薄膜发生开环反应的结论。     

纳秒激光辐照对类金刚石薄膜的损伤及改性

利用Nd:YAG纳秒激光(波长分别为355、532和1 064 nm)辐照由电子束蒸发技术制备的类金刚石(DLC)薄膜,通过光学显微镜、光学轮廓仪和拉曼光谱仪等分析了辐照后的薄膜样品,结果表明:不同波长的单脉冲激光辐照时,DLC膜的激光损伤阈值不同;同一波长的多脉冲激光辐照时,损伤阈值低于单脉冲辐照阈值;脉冲激光辐照对DLC膜具有改性作用,受辐照薄膜区域表层发生了石墨化、剥落和气化效应,致使DLC膜表面出现了隆起和弹坑,隆起高度和弹坑深度与激光能量密度大小和脉冲个数有关.     

电子对F46镀银二次表面镜光学性能影响研究

空间电子辐照是对航天器用热控材料性能产生影响的重要因素.研究了F46镀银二次表面镜在电子辐照作用下的光学性能和质量损失的变化规律,并应用扫描电镜和电子能谱对电子辐照前后试样表面形貌和元素组成变化进行了分析.研究表明,在相同能量的电子辐照下,随电子辐照通量的增加,该二次表面镜的表面铟和氧含量减少,碳含量和质量损失增加,其表面导电层被破坏,聚全氟乙丙烯的表面碳化,致使F46镀银二次表面镜光学性能下降.     

在线紫外辐照辅助沉积柔性ITO薄膜的研究

显示技术正朝着柔性化、超薄化方向发展,低温制备柔性ITO薄膜已经成为一大趋势.本文在射频磁控溅射过程中,引入在线紫外辐照,室温条件下在有机衬底上制备柔性ITO薄膜的工艺,其最低方块电阻为5Ω,电阻率为2.5×10 -4Ω·cm,透光率为92%,远远优于未采用紫外辐照制备的柔性ITO薄膜.我们用四探针测试仪、分光光度计、原子力显微镜、X射线衍射仪等测试仪器,对未采用和采用在线紫外辐照制备的薄膜进行测试,分析探讨了紫外线辐照对薄膜的光电性能、表面形貌和生长取向的影响.研究结果表明:在紫外线的照射下,ITO薄膜表面形貌得到改善,晶界缺陷减少,生长更均匀,致密度更好,在降低薄膜电阻率的同时,提高了薄膜在可见光区的透射率,在紫外辐照下,ITO薄膜更趋于〈222〉的择优取向,且平均晶粒尺寸变大,结晶度提高,宏观表现为薄膜的电阻率降低.     

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...     

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.     

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.……     

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.     

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.