一种硅表面化学清洗方法

本文介绍了一种温和简洁的硅表面化学清洗方法，它主要包括H2SO4：H2O2溶液清洗和HF：C2H5OH刻蚀两个过程。清洗前后的硅表面用原子力显微镜（AFM）、X射线光电子能谱（XPS）和反射高能电子衍射（RHEED）等技术进行表征。结果表明，运用此方法能得到平整清洁的Si表面。为了延缓H-Si表面在空气中被氧化的速率和防止杂质污染，我们提出用无水乙醇（C2nsOH）来保护H-Si表面。300℃除气前后XPS的对比结果表明，清洗后的Si表面不存在B，但吸附少量F，以及化学吸附和物理吸附都存在的C和O。根据Si2p芯能级的同步辐射光电子能谱（SRPES），可以确定Si氧化物薄膜的厚度只有一个单层，经1000℃退火25min后，XPS和SRPES的结果表明Si表面已经非常清洁，并且出现了两个Si的表面态。     

Ti/AlN陶瓷界面反应的热力学研究

对AlN陶瓷在室温和超高真空条件下蒸镀金属钛过程的界面反应进行了热力学研究，并用X光电子能谱（XPS）进行了验证，表明在金属钛沉积以前AlN陶瓷在空气中表面部分被氧化，当样品沉积了金属钛后，刚沉积上的钛是氧化状态，随着钛沉积厚度的增加，表面TiN和Al2O3的成分都增加。     

PbTe薄膜表面氧化机理研究

用分子束外延方法在BaF2（111）衬底上生长了PbTe单晶薄膜,原子力显微镜（AFM）的表面形貌表征显示PbTe表面具有单原子层的平整性,并观察到由螺位错形成的螺旋台阶面。高分辨X射线衍射（HRXRD）测量得到PbTe（111）衍射峰的线宽〈100afc sec,表明薄膜具有优良的晶体结构特性。然后将样品暴露于大气环境中3个月后,用X射线光电子谱（XPS）分析了PbTe表面的氧化机理,发现PbTe表面氧化形成了PbO和TeO2,接着将样品在超高真空中加温,同时测量样品表面的Pb、Te、O元素价态、束缚能、含量等参量随温度的变化,发现在温度达到475℃时PbTe样品表面的氧化层已除去,获得了较干净的PbTe表面,为PbTe光电器件工艺提供了实验依据。     

GaAs和（Cs，O）／GaAs热处理工艺的XPS研究

用X射线光电子能谱(XPS)研究了GaAs(100)面基片的化学清洗、热净化、(Cs，O)激活后加热的处理效果。GaAs的氧化过程是：首先，As氧化为低价态，然后Ga被氧化，再就是As氧化为高价。确保样品从刻蚀清洗到超高真空环境中，表面Ga没有被氧化，就可在较低的温度热净化，获得As稳定的且原子级清洁的GaAs表面。净化后GaAs表面Ga含量越高，则(Cs，O)激活后形成氧化物越多，从而形成了界面势垒，使电子逸出概率降低。     

GaAs和(Cs,O)/GaAs热处理工艺的XPS研究

用X射线光电子能谱(XPS)研究了GaAs(100)面基片的化学清洗、热净化、(Cs,O)激活后加热的处理效果。GaAs的氧化过程是:首先,As氧化为低价态,然后Ga被氧化,再就是As氧化为高价。确保样品从刻蚀清洗到超高真空环境中,表面Ga没有被氧化,就可在较低的温度热净化,获得As稳定的且原子级清洁的GaAs表面。净化后GaAs表面Ga含量越高,则(Cs,O)激活后形成氧化物越多,从而形成了界面势垒,使电子逸出概率降低。     

超高分子量聚乙烯微孔膜的亲水改性研究——（I）臭氧活化接枝反应及其表征

利用O3处理超高分子量聚乙烯（UHMWPE）微孔膜，使其表面产生活性点，然后将甲基丙烯酸（MAA），甲基丙烯酸羟乙酯（胍MA）接枝在膜表面上．用ATR—FTIR、XPS等对O3活化及接枝前后的UHMWPE微孔膜结构进行了表征，接触角测试表明接枝后微孔膜具有较好的亲水性．     

真空容器的制造与清洗技术

一、前言在超高真空条件下进行实验时,需要具备能够获得超高真空的设备。这类设备既可以订购,也可以自己加工制作。无论如何,最重要的是要熟悉制造过程,掌握超高真空技术这种尖端科学技术知识。真空容器的制造技术已不神秘,问题在于如何对容器表面进行加工以及减少出气量。即必须在容器的表面加工和表面清洗上狠下功夫。     

铬及铍表面辉光放电清洗的研究

本文对He辉光放电清洗后的铬（Cr）表面杂质去除情况和铍（Be）样品真空出气量变化进行了实验研究。使用场发射扫描电镜和表面质量测量仪对比观察了不同放电参数处理后的Cr样品表面，结果显示在放电功率为200～300W、放电室压强为1～10Pa、清洗时间为10-20min时可较好地清除表面杂质和降低表面粗糙度；对辉光放电处理前后Be样品出气情况的实验对比结果显示，清洗后1h内总出气量约降为清洗前的1／6。     

PLD生长的ZnO薄膜的微结构及其发光特性研究

在不同的衬底温度下，通过脉冲激光淀积（PLD）方法在Si衬底上生长出c轴高度取向的ZnO薄膜。ZnO薄膜的结构分别通过X射线衍射（XRD）和广延X射线吸收精细结构（EXAFS）来表征，而表面成份和化学态则通过X射线光电子能谱来研究。利用光致发光（PL）来研究样品的发光特性。XRD结果和EXAFS结果都表明了500℃时生长的ZnO薄膜的结晶性比300℃时生长的要好。EXAFS结果和XPS结果显示，300℃时生长的ZnO薄膜处于富氧状态，而500℃时生长的则处于缺氧状态。结合XRD谱、EXAFS谱、XPS谱和PL谱的结果可以看到：随着ZnO薄膜的结晶性变好，它的紫外发光增强；另一方面，随着ZnO薄膜中O的含量减少，绿光发射变强。我们的结果表明绿光发射与ZnO中氧空位（V0）有关。     

透射式p型GaN(0001)光电阴极的表面洁净度及表征研究

在p型GaN(0001)光电阴极的化学腐蚀和高温热清洗的处理过程中,为了评价化学处理和热清洗的效果,利用X射线光电子谱分析了不同阶段的光电阴极表面状况。结果表明,开始处理前,表面存在严重的C、O污染,C的表面覆盖率接近2个单原子层,而O稍小于1个单原子层,并且表面生成Ga_2O_3氧化层。经2:2:1的H_2SO_4:H_2O_2:H_2O混合溶液化学腐蚀处理后,C的表面覆盖率为0.36个单原子层,O的覆盖率为0.21个单原子层,化学腐蚀去除了大部分的C、O污染,露出了体材料。700℃高温热处理后,表面的C覆盖率低于百分之一个单原子层,而O的覆盖率也仅为0.07个单原子层,基本去除了C、O污染,并且表面Ga:N比为1.01:1,达到体材料的理想配比。GaN光电阴极在H_2SO_4/H_2O_2混合溶液中腐蚀15 min并在700℃下真空热清洗30min后,可以有效去除C、O污染和氧化物,获得洁净表面,进行Cs-O激活后可以获得负电子亲和势。     

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.