磁性蓄冷材料HoCu2的雾化成形研究

采用旋转盘离心雾化设备制备了磁性蓄冷材料HoCu2粉末，并对雾化粉末进行了分析。结果表明，粒径＜154μm雾化粉末的比例较高，接近30％，粉末形态主要以球形颗粒为主，仅有极少量的形状不规则颗粒；粒径在矽φ154～300μm粉末的比例最大，收得率在60％以上，与粒径＜φ154μm粉末相比，残缺颗粒的比例有所增加；大尺寸粉末（＞φ300μm）的比例很低，仅为9％左右，除了少量带有缺陷的球形颗粒外，绝大多数为薄片状颗粒．雾化粉末的Cu含量为43．59％（质量分数），氧含量为0．055％（质量分数），为单一HoCu2相结构，无其它杂相存在。     

Mo-Cu高能球磨过程实验研究及固溶度数值模拟

采用高能球磨方法对Mo-3%(质量分数)Cu、Mo-10%(质量分数)Cu复合粉末进行机械合金化加工,球磨时间为0～50h。通过扫描电镜及X射线衍射等对复合粉末的形貌、X射线衍射特征进行了分析,并对Cu在Mo中的固溶度用热力学方法进行了研究。结果表明,通过机械合金化方法可以得到超细小且均匀的纳米晶复合粉末,平均晶粒尺寸在60nm左右;从热力学平衡角度出发,通过细化晶粒来提高Cu在Mo中的固溶度极限可以用数值模拟来表达。     

我国纳米碳酸钙的研究和生产情况简述

碳酸钙按平均粒径可分为5个粒度等级：微粒（〉5μm）、微粉（1～5μm）、微细（0．1～1μm）、超细（0．02～0．1μm）、超微细（≤0．02μm）。纳米碳酸钙材料是指颗粒尺寸大小在1-100nm的超细粉末碳酸钙。     

渗铜对QT500-7组织及性能影响的研究

为提高QT500-7的表面力学性能，采用固体渗金属方法在其表面制备渗铜层，利用金相显微镜、扫描电镜、硬度计研究了铜在其中的扩散行为及其对组织和硬度的影响。根据计算结果可知，随着处理温度的升高，球铁基体相中的Cu固溶度随之提高，在1 173 K温度下固溶度可达0.56%(质量分数),铜在球铁中的扩散距离随扩散温度的升高、扩散时间的延长而增大，在1 173 K保温8 h的条件下其理论扩散深度为23μm。试验结果表明：Cu在QT500-7中的扩散抑制了珠光体转变阶段铁素体晶粒的长大，使珠光体的含量增多，铜向球铁中的扩散使得制备的渗铜层处石墨数量增加，缩小了与其心部石墨数量的差距。观察到的扩散层深度为40μm,较铜向铁的完整晶体的理论扩散距离有所增大。而球铁表面制备的渗铜层硬度较原始试样的略有提高。     

直流等离子体法制备Cu纳米粉

本实验利用直流等离子体法制备了Cu纳米粉末,并系统研究了工艺参数对Cu纳米粉末粒子产率、粒径和粒径分布规律的影响。正交实验、扫描电子显微镜、产率及粒径分析结果表明:Cu纳米粉末粒子最佳制备工艺参数为电流(380±5) A、制粉室内N₂气体比例为(15±2)%、风机转速为2 400～2 500 r/min。在此工艺条件下获得的Cu纳米粉末粒子呈球形,Cu纳米粉末粒子粒径分布均匀,分布范围较窄,粒径约为100 nm。随着N₂气体比例增加,电流强度增大,Cu纳米粉末产率提高,但同时会导致Cu纳米粉末粒子平均直径增大、粒径分布变宽。然而,随着轴流风机转速的提高,Cu纳米粉末产率提高,并且Cu纳米粉末粒子平均直径减小、粒径分布变窄,这与较快的转速引起Cu棒表面原子蒸气浓度下降有关。     

B4C超细粉末的制备及烧结

采用气流粉碎对B4C粗粉（比表面积0.52m^2/g，中位粒径20.4μm)进行了一系列粉碎实验，研究了气流粉碎次数，成形压力和烧结温度对烧结密度的影响。结果表明，当粉碎次数达到3次后，可获得＜1μm的B4C超细粉末。经过4次气流粉碎的B4C超细粉末的比表面积为2.53m^2/g，中位粒径为0.56μm；该粉末分别于2200和2250℃无压烧结1h，其烧结密度分别达到理论密度的78．6％ 82．5％，平均晶粒尺寸分别为28和50μm，抗压强度分别为390和555MPa。     

机械合金化制备Cu-Fe过饱和固溶体及其时效分解

采用机械合金化工艺制备Cu-xFe(x=1,2,4,质量分数/%)过饱和固溶体,研究时效对其硬度和导电性能的影响.X-ray衍射分析结果表明:机械合金化显著提高了Fe在Cu中的固溶度,Cu-4Fe复合粉末经32h球磨.Fe完全固溶于Cu基体中,此时Cu晶粒尺寸为20nm,点阵常数降低到0.3621nm.硬度和导电率测试结果表明:时效处理能促进过饱和固溶体发生分解,Cu-4Fe过饱和固溶体冷压成型压坯在400℃保温8h后显微硬度HV由时效前的175降低到96,电导率由35%IACS(国际退火铜标准)提高到60%IACS.     

激光衍射法中光学模型对B4 C粉末粒度分布测量结果的影响

选了四种不同平均粒径的B4C粉末分别用激光衍射法仪中Fraunhofer（夫朗和费）衍射和Mie（米氏）散射光学模型测量其粒度分布和平均粒度，结果表明，对于粒径界于10－15μm之间的粉末，无需知道材料对光的折射率和吸收率，其应用Fraunhofer衍射理论测理的结果与应用Mie散射理论测得的结果近似，但分布线有一定的区别，对于＞15μm粉末，在两种模型下分布曲线与平均粒径皆接近；而对于＜10μm的粉末，必须采用Mie散射光学模型，并需预先知道材料的光学特性。     

BaCeO3：Eu^3＋的合成及发光性能研究

采用高温固相反应法制备了Eu^3＋掺杂BaCeO3发光粉。分别用X射线粉末衍射、荧光光谱分析等手段研究了发光粉的晶体结构以及光致发光性能。XRD结果表明，Eu^3＋掺杂浓度达到6％（原子分数）时，仍然能够形成纯相的固溶体BaCe1-xEuxO3。荧光光谱检测结果表明，BaCe1-xEuxO3发光粉的激发光谱由强度很大的宽激发带（230-370nm）和锐线谱（峰值位于397和466nm）组成，其中宽激发带源于O2^-—Ce^4＋电荷转移，锐线谱属于Eu^3＋的f-f跃迁吸收。BaCe1-xEuxO3的发射谱除了常见的^5D0→^7Fj（J=0-4）跃迁发射外，还有来自较高能级激发态^5D1的跃迁^5D1^7→Fj（J=1，2）；随着Eu^3＋掺杂浓度的提高，其发光强度也逐渐增强，当掺杂浓度达到15％时，出现浓度猝灭现象。     

非晶铁合金汞基磁流体的制备和性质

以乙醇为反应介质用NaBH4还原铁金属离子,得到用于制备汞基磁流体的非晶纳米铁合金粒子．用原子吸收光谱、透射电子显微镜、X射线粉末衍射和磁天平等对合金粒子和相应的汞基磁流体的性质进行了表征．铁合金粒子中氧化物的含量（质量分数）为1．2％,粒径12nm,饱和磁化强度16400kA／m．这种磁粒子的氧化物含量低,表面金属性强,能够充分分散于汞中,得到饱和磁化强度为210kA／m、稳定的汞基磁流体（性能保持18个月不变）．     

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.