非晶稀土——过渡金属磁光薄膜热稳定性研究

采用射频磁控溅射方法制备非晶ＤｙＦｅＣｏ磁光薄膜。样品的克尔回线、转矩曲线的测试显示，薄膜具有优良的磁和磁光性能。退火研究表明，随着退火时间的增加，矫顽力下降，垂直磁各向异性能减少，但克尔角变化不明显，其内在机制与薄膜中的微缺陷和应力的弛豫过程有关。     

不同工艺条件对FePt-AlN纳米薄膜磁性影响的研究

利用磁控溅射方法,在加热的单晶MgO(100)基片上制备了以AlN为母体的FePt薄膜,再经过真空热处理后,得到了具有垂直磁各向异性且无磁交换耦合作用的FePt薄膜;同时,研究了掺杂AlN含量、薄膜的厚度及退火温度对薄膜的磁性能的影响.结果表明,非磁性相AlN的添加能够降低磁交换耦合作用,但同时也会破坏薄膜的垂直磁各向异性.降低薄膜厚度,有利于改善薄膜的垂直磁各向异性,FePt-AlN薄膜的厚度为6nm且掺杂AlN含量达到40%时,经650℃热处理1h后薄膜具有良好垂直磁各向异性、适中矫顽力且无磁交换耦合作用.     

不同退火时间对[Ag/FePt]_(10)多层膜磁性能和微结构的影响

采用射频磁控溅射的方法,在玻璃基片上制备了不同Ag层厚度的[Ag/FePt 2nm]10多层薄膜,经550℃真空热处理后,得到L10有序结构的FePt薄膜.实验结果显示,FePt单层薄膜经550℃退火30min后其易磁化轴处于垂直方向和面内方向之间,而550℃退火60min后其易磁化轴处于垂直于膜面方向,垂直矫顽力和面内矫顽力分别为634和302kA/m;真空退火后[Ag/FePt]10多层膜表现为面内磁晶各向异性,550℃退火60min后[Ag 2.8nm/FePt 2nm]10多层薄膜垂直矫顽力和面内矫顽力分别为309和778kA/m,并且随着Ag层的加入,部分FePt颗粒已经被Ag原子隔开了,颗粒之间的交换耦合作用变弱了.     

热处理对Tb0.27Dy0.73Fe2巨磁致伸缩薄膜性能的影响

本文研究了热处理对Tb0.27Dy0.73Fe2薄膜磁性及巨磁致伸缩性能的影响。XRD分析表明制备态的Tb0.27Dy0.73Fe薄膜为非晶态,并且在450℃退火仍然保持非晶态,制备态的Tb0.27Dy0.73Fe2薄膜显示垂直磁各向异性,在退火后向平行磁各向异性变化。热处理提高了Tb0.27Dy0.73Fe2薄膜在低磁场下的磁致伸缩特性。     

热处理对Tb0.27Dy0.73Fe2巨磁致伸缩薄膜性能的影响

本文研究了热处理对Tb0.27Dy 0.73Fe2薄膜磁性及巨磁致伸缩性能的影响.XRD分析表明制备态的Tb0.27Dy 0.73Fe2薄膜为非晶态,并且在450℃退火仍然保持非晶态,制备态的Tb0.27 Dy0.73Fe2薄膜显示垂直磁各向异性,在退火后向平行磁各向异性变化.热处理提高了Tb0.27Dy0.73Fe2薄膜在低磁场下的磁致伸缩特性.     

钡铁氧体垂直磁化膜磁各向异性研究

钡铁氧体垂直磁化膜可用作高密度磁记录介质。本文研究用低温ＲＦ磁控溅射法制备非晶薄膜，经晶化处理所得到的垂直磁化膜的饱和磁化强度Ｍｓ、矫顽力Ｈｃ及垂直磁各向异性常数Ｋｕｌ、Ｋｕ２与退火温度Ｔ的关系，并对所呈现出的变化规律作了简单解释。介绍了依据转矩曲线的形状来判断薄膜垂直性优劣的方法，从转矩曲线出发，探讨了影响薄膜磁各向异性的因素。     

Cu覆盖层对CoCrPt颗粒膜的微结构和磁特性的影响

在室温下,应用对靶磁控溅射设备制备了系列Cu(x nm)/CoCrPt(40nm)/Cu(20nm)三明治结构的纳米颗粒膜,随后进行了原位退火.实验发现Cu覆盖层的厚度(x)对颗粒膜的微结构和磁特性有很大影响.样品垂直方向的矫顽力在x=11nm时达到最大,为138kA/m,平行于膜面方向的矫顽力基本上与x的变化无关,且所有的样品都显示出很强的垂直各向异性.退火后的CoCrPt薄膜呈六角密堆积(HCP)结构,AFM和MFM测量显示在x=11nm时,颗粒的平均粒径和磁畴尺寸均为最小.开关场分布(SFD)的测量表明,退火有效地减弱了颗粒间的交换耦合作用.     

退火工艺对Finemet纳米合金磁性能的影响

为改善Finemet合金的磁性能,通过氩气退火和横、纵磁应力退火对合金进行热处理,研究退火工艺对合金磁性能及微观结构、形貌的影响.使用LCR数字电桥法、共地三电压法及冲击法测试磁性能,利用场发射扫描电镜观察Finemet合金的非晶、纳米晶形貌,采用X射线仪分析Finemet合金的结构.研究表明,540℃氩气退火使合金的初始导磁率μi达最高值且矫顽力H c最低,非晶基体出现bccα-Fe(Si)纳米晶颗粒,580℃氩气退火使纳米晶数量和尺寸增加,磁性能下降;540℃横磁退火可获得狭长扁平的磁滞回线、低剩磁比Br/Bs和铁损P c,540℃纵磁退火可获得矩形磁滞回线、高Br/Bs和P c,横、纵磁退火均使μi和H c降低.因此,合理的退火工艺可优化Finemet合金磁性能,以适应不同的应用领域.     

感生各向异性对溅射Ni80Co20合金膜的磁及磁电阻性能的影响

采用磁控溅射方法,在诱导磁场下制备了一系列不同厚度的Ni80Co20合金薄膜。并研究了外磁场诱导的面内感生各向异性随膜厚度及退火工艺的依赖关系,以及各向异性对样品的磁电阻回线和矫顽力的影响。实验发现,外磁场诱导的面内感生各向异性随薄膜厚度的增加而逐渐减弱,沿面内易轴方向测得的磁电阻回线在矫顽力处具有很尖锐的磁电阻变化峰,因而具有很高的磁电阻灵敏度,沿易轴方向的矫顽力比在难轴方向测得的矫顽力大,两者都随膜厚的增加而增大,其差别随膜厚的增加而减小,样品经400℃真空退火后,面内感生各向 异性基本消失,矫顽力也显著降低,实验还发现,当薄膜厚度小于Ni80Co20合金的电子平均自由程（－15ns）时,各向异性磁电阻、△ρ和△ρ/ρ都陡然下降,当D＞20ns时,△ρ已基本趋于饱和,△ρ/ρ而仍继续增大,以上实验结果对Ni80Co20合金膜在磁记录和磁传感技术方面的应用具有实际意义。     

退火对低温射频磁控溅射Ba铁氧体薄膜结构及磁特性的影响

用RF磁控溅射法，在纯Ar气中，硅基片不加热的情况下，制备了Ba铁氧体薄膜，研究了退火温度对薄膜c轴垂直取向、结构及磁特性的影响，结果表明薄膜在700℃氧气中退火可获得良好c轴垂直膜面的择优取向，该薄膜的饱和磁化强度和矫顽力分别为Ms=296emu／cm3，Hc=308761A／m。退火温度过低或过高，都不利于形成c轴垂直膜面的择优取向。     

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...     

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.     

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.     

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.     

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.……     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.