退火处理对TiNi合金钽镀层微观组织结构的影响

采用多弧离子镀的方法在TiNi形状记忆合金表面镀覆了厚度为3μm的钽镀层,并对其进行了不同温度的真空退火处理.通过X射线衍射(XRD)研究发现,未经退火的镀层是由不稳定的β-Ta组成,分别经过700, 800, 900℃,1h退火后转变为α-Ta.透射电子显微镜(TEM)的观察发现,采用多弧离子镀的方法可以在TiNi合金表面得到纳米尺寸的β-Ta镀层.在700℃退火时可以得到由40 nm左右的微晶和150 nm左右的较大晶粒混合而成的α-Ta.当退火温度为900℃时,镀层主要由尺寸较大而且均匀的α-Ta组成.     

Fe/C复合纳米材料的制备研究

以强酸为絮凝剂，将碱性溶液中的水性中间相沥青絮凝，从而使水性中间相沥青在酸性介质中形成炭基溶胶和凝胶。将此炭基溶胶和硝酸铁溶液混合形成复合溶胶、凝胶，进而采用醇水交换和超临界干燥制备出粒度为5nm-20nm的Fe/C复合纳米材料。考察了硝酸铁和水性中间相沥青的比例，以及热处理条件对Fe/C复合纳米材料织构和结构的影响。利用透射电镜、物理吸附、ICP－AES、X－射线衍射、热重等表征手段对Fe/C复合纳米材料特性和热处理的变化规律进行了研究。结果表明：通过改变炭基溶胶中硝酸铁的加入量可以制备不同铁含量的Fe/C复合纳米材料；在惰性气氛下，于较低温度热处理时，Fe/C复合纳米粉中铁是以Fe2O3的形式存在，热处理温度升高（900℃）后Fe2O3被还原为单质铁，且金属颗粒团聚长大，在高温（1300℃）时，铁以Fe3C的形式存在，颗粒进一步长大且有部分炭石墨化。在还原性气氛下，在300℃－500℃热处理范围内，随温度的升高铁被还原为单质铁。     

纳米氧化铋基材料高温相变的研究

以分析纯Bi(NO3)3·5H2O和Y(NO3)·6H2O为原料制备纳米β-Bi2O3和Bi2O3-Y2O3(75%(摩尔分数)Bi2O3 25%(摩尔分数)Y2O3)粉体,平均粒度分别为40和30nm.经TG-DTA、高温XRD以及高温拉曼的研究结果表明,亚稳态的纳米β-Bi2O3粉体在升温过程中于420℃先向低温稳定的α-Bi2O3转变,在720℃时向δ-Bi2O3相转变,降温过程则是由δ→β→α.由于纳米Bi2O3具有很高的活性,使得相变温度比微米Bi2O3有所降低.纳米Bi2O3-Y2O3复合粉体升温过程中,Y2O3的固溶反应在较低温度(400℃)开始,500℃时β-Bi2O3完全转变为δ相,同时Y2O3完全固溶到δ-Bi2O3晶体中.Y2O3的掺杂使得Bi2O3的β→δ相转变温度大幅降低.     

含钽树脂先驱体转变生成TaC的过程研究

液相先驱体浸渍法制备的C/C-TaC复合材料可望提高C/C复合材料的烧蚀性能.本研究借助XRD、SEM对含钽树脂先驱体不同温度热处理后物质的成分与形貌进行分析,并结合钽液的DSC-TG曲线揭示了含钽树脂转变生成TaC过程的反应机理.研究表明：含钽树脂中钽液是作为呋喃树脂的固化剂起作用,显著降低了呋喃树脂的固化温度,100℃低温热处理树脂便固化,同时钽液中的TaF5水解生成TaO2F.在真空保护气氛下,温度升高到800℃以上,含钽树脂中的部分TaO2F会分解成Ta2O5和气体TaF5.随后,Ta2O5在1000℃时开始被树脂炭还原化合生成颗粒尺寸〈1μm的TaC颗粒.要控制钽的损失可通过长时间低温处理（室温～100℃）和通无水氨（150～500℃）来实现.     

富硼渣钠化法制备硼砂的实验研究

采用X射线衍射分析(XRD)方法分析表明,富硼渣中的硼组分主要以Mg2B2O5形式存在,而钠化渣中的硼组分以Na4B2O5和NaBO2晶相形式析出.为提取富硼渣中的硼,考察了热处理温度、碳酸钠加入量、热处理时间、水浸温度等因素对钠化渣中硼浸出率的影响.同时考察了富硼渣中w(Al2O3)、w(CaO)、w(B2O3)、m...     

Si片上PbTiO3薄膜的XPS研究

用溶胶 凝胶方法在Si上成功地制备了钙钛矿型的PbTiO3薄膜。X射线衍射结果显示 ,在热处理温度为 750～ 90 0℃范围内 ,随温度升高 ,薄膜由多晶结构转变为定向结晶。X射线光电子能谱分析发现 ,薄膜表面存在SiO2 薄层 ,其厚度大约为 0 6nm ,该薄层是在制膜过程中衬底Si通过PbTiO3薄膜扩散到表面与大气中的O2 反应而形成的。在 750℃热处理的薄膜 ,膜层中不含SiO2 ,但温度升高 ,膜层中存在SiO2 成分 ,这可能是Si在向表面扩散过程中与膜中的O反应生成的。表面SiO2 可通过Ar离子的轻微溅射而消除 ,而膜内SiO2 成分只能通过调节工艺参数来消除     

(1-x)TiO_2-xTa_2O_5薄膜的光学性能研究

TiO2-Ta2O5薄膜是较新颖的光学薄膜,由均匀混合的两种化合物薄膜材料作为膜料研制而成,本文采用离子辅助蒸发的方法,以不同配比的Ta2O5和TiO2混合物为初始膜料在K9玻璃上制备了TiO2-Ta2O5混合薄膜,并对其光学性能进行研究.实验结果表明,TiO2-Ta2O5薄膜在可见光范围内有较高的透射率,消光系数在10-3～10-4数量级,折射率在1.80～2.07范围内变化(550nm),是理想的光学镀膜材料.随着Ta2O5含量从0增加到20%,光学带隙从3.266eV单调增加到3.417eV,并用Kayanuma提出的模型解释了透射谱中吸收边的漂移现象.     

退火对镀钽TiNi合金微观组织结构和血液相容性的影响

采用原子力显微镜(AFM)和X射线衍射分析(XRD)研究了退火处理对TiNi合金钽镀层微观组织结构的影响,研究表明采用多弧离子镀在TiNi合金表面沉积得到了β-Ta镀层,经退火处理后,钽镀层的表面粗糙度增加,亚稳定的β-Ta相完全转变为稳定的α-Ta相.采用血小板粘附试验研究了退火对镀钽TiNi合金血液相容性的影响.发现经过退火处理后血小板粘附数量明显降低,血小板没有发生聚集和变形,只有少数长出了伪足,即血小板基本未被激活,说明退火改善了镀钽TiNi合金的血液相容性.     

X射线反射法和椭圆偏振法结合测量热处理溶胶-凝胶ZrO2薄膜的结构和光学参数

采用溶胶-凝胶法在硅片基底上制备ZrO2薄膜,在150℃～750℃范围内不同温度下进行热处理,研究了热处理对膜层结构和光学性能的影响。X射线反射用于膜层厚度和界面粗糙度分析,结果表明热处理温度由150℃升至750℃,膜层厚度由常温状态下的112.3nm减小到34.0nm,表面和界面粗糙度均小于2nm。以X射线反射法测得的膜层厚度为初始值,对椭圆偏振仪的测量结果进行拟合,得到不同温度的膜层折射率,结果表明热处理温度为550℃时膜层折射率达到最大值。X射线反射作为直接的膜层厚度测试手段,所得结果为准确分析椭偏光谱提供了参考。     

不同碳源对纳米锌铝尖晶石合成及颗粒粒径的影响

以硝酸铝、硝酸锌和柠檬酸为原料,以炭黑和酚醛树脂为碳源,采用溶胶-凝胶法制备了纳米锌铝尖晶石粉体,研究了高温还原气氛下不同碳源对纳米锌铝尖晶石合成及颗粒粒径的影响,并以高温氧化气氛热处理、无碳引入的试样作对比。研究表明:在还原气氛下,引入碳源的试样在600℃热处理后,锌铝尖晶石峰不明显,主要是因为碳起空间位阻作用,阻碍了离子传质;800℃热处理后可合成锌铝尖晶石,且纳米颗粒尺寸较小(20~30nm);热处理温度升高至1 000℃时,纳米锌铝尖晶石颗粒尺寸变化不大,碳的空间位阻作用抑制了颗粒长大和烧结。与炭黑相比,酚醛树脂抑制锌铝尖晶石颗粒长大的效果更好,可能因为树脂碳化后呈玻璃态,空间阻隔作用更强。但热处理温度不低于1 200℃时,纳米锌铝尖晶石易被CO或C还原,锌以Zn(g)的形式逸出,只有α-Al2O3相。然而,在空气气氛下,600℃热处理后即可合成纳米锌铝尖晶石,但热处理温度从600℃升至800℃时,锌铝尖晶石颗粒长大较明显,颗粒尺寸从27.5nm增至54.6nm,并呈烧结状。     

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.