纳米晶PCT薄膜的合成与表征

纳米材料的制备技术结合Ｓｏｌ－Ｇｅｌ工艺在（１００）单晶硅上制备了粒径在２０￣８０ｎｍ的多晶ＰＬＴ（Ｐｂ１－ｘＬａｘＴｉＯ３）纳米晶膜，并用ＩＲ、ＴＧＡ、ＸＲＤ、ＳＥＭ等对膜的制备过程及结果进行了研究。结果表明，所制备的ＰＬＴ纳米晶膜属多晶钙钛矿结构，薄膜表面平整致密，厚度均匀，约为１ｕ，颗粒为球形或椭球形，粒度呈对称分布。     

溶胶－凝胶工艺参数对（Pb，La）TiO_3薄膜结构的影响

系统地研究了溶胶－凝胶（Ｓｏｌ－Ｇｅｌ）方法制备（Ｐｂ_（１－Ｘ）Ｌａ_ｘ）Ｔｉ_（１－ｘ／４）Ｏ_３（简称ＰＬＴ）薄膜时催化剂（或ｐＨ值）、溶液浓度在室温下对形成溶胶和凝胶的影响规律，用Ｘ射线结构分析和ＳＥＭ研究了热处理工艺对薄膜结构及晶粒尺寸的影响。实验表明，浓度、醋酸含量都存在一个最佳的范围，且随铜（Ｌａ）含量的增加，该范围减小；实验还发现，随着Ｌａ含量的增加，薄膜的晶化温度降低。在单晶（１００）Ｓｉ衬底上成功地制备出了具有钙钛矿型结构、厚度约为２００ｎｍ、均匀、致密、无裂纹的ＰＬＴ晶态薄膜。     

超微晶Fe_（73．5）Cu_1Nb_3Si_（13．5）B_9形成过程的等温

利用热重法（ＴＧ）研究了超微晶Ｆｅ＿（７３．５）Ｃｕ＿１Ｎｂ＿３Ｓｉ＿（１３．５）Ｂ＿９形成的等温晶化动力学过程，由Ｊ－Ｍ－Ａ方程求出了晶化动力学常数ｎ（ｘ）和Ｅ＿ｃ（ｘ）对ｘ的曲线。晶化形核过程中这些曲线的变化关系可以很好的由Ｃｕ的作用来说明。同时与等温ＤＳＣ的结果比较表明ＴＧ更能给出晶化初期的形核信息。     

溶胶—凝胶工艺参数对（Pb,La）TiO3薄膜结构的影响

系统地研究了溶胶－凝胶（Ｓｏｌ－Ｇｅｌ）方法制备（Ｐｂ１－ｘＬａｘ）Ｔｉ（１－ｘ／４）Ｏ３（简称ＰＬＴ）薄膜时催化剂（或ｐＨ值）、溶液浓度在室温下对形成溶胶和凝胶的影响规律，用Ｘ射线结构分析和ＳＥＭ研究了热处理工艺对薄膜结构及晶粒尺寸的影响。实验表明，浓度、醋酸含量都存在一个最佳的范围，且随镧（Ｌａ）含量的增加，该范围减小；实验还发现，随着Ｌａ含量的增加，薄膜的晶化温度降低。在单晶（１００）Ｓｉ衬     

Li_2SO_4－Li_2O－P_2O_5体系非晶态Li~＋离子导体的研究

本文给出了非晶态Ｌｉ￣＋离子导体Ｌｉ＿２ＳＯ＿４－Ｌｉ＿ｂＯ－Ｐ＿２Ｏ＿５体系的制备条件、导电性以及差热分析（ＤＴＡ）结果，同时还对其晶化过程进行了研究。结果表明，首先成功地制备出了以Ｌｉ＿２ＳＯ＿４为基质的非晶态离子导电材料，并且在３５０℃时组成为Ｌｉ＿２ＳＯ＿４－０．３０Ｌｉ＿２Ｏ－０．７０Ｐ＿２Ｏ＿５样品的电导率最大（σ＝６．７８×１０￣（－３）Ω￣（－１）ｃｍ￣（－１）），这一结果与ＤＴＡ测量结果取得一致，ＳＥＭ证明是由于非晶母体部分晶化造成的。采用液氮温区急冷技术已成功的将该状态稳定到了室温，稳定后的态再重测其电导率随温度变化关系，相应的电导率提高３０％左右，如果找到某种合适的稳定剂使其一直处于微晶态，将为高电导率离子导体的制备提供一条新路。     

用Sol─Gel法制备PZT铁电陶瓷及薄膜

用Ｓｏｌ－Ｇｅｌ法制备了Ｐｂ（Ｚｒ＿（０．５）Ｔｉ＿（０．５））Ｏ＿３（ＰＺＴ）铁电陶瓷与薄膜，观察了它们的结晶情况并测定了它们的电学性能。利用Ｓｏｌ－Ｇｅｌ法，可降低ＰＺＴ陶瓷粉料的预烧温度约２００℃，所得陶瓷致密，晶粒均匀；具有较好的介电性能。ＰＺＴ陶瓷显示弥散相变特征。ＰＺＴ薄膜的晶化受基底影响很大。基底晶格越完整，与ＰＺＴ薄膜的晶格失配率越小，ＰＺＴ薄膜的晶化就越好。采用ＰｂＴｉＯ＿３过渡层促进ＰＺＴ薄膜在镀铂硅片上晶化。ＰｂＴｉＯ＿３过渡层与ＰＺＴ薄膜构成串联电路。其表现电学性能与相应的ＰＺＴ体材料相近。     

ZrO_2－Y_2O_3纳米晶的制备及其湿敏性能

以化学共沉淀法为基础，配合高速剪切均质并添加表面活性剂制备了粒径为２０～４０ｎｍ的ＺｒＯ＿２－Ｙ＿２Ｏ＿３纳米晶，经ＸＲＤ分析为稳定立方相结构。用ＺｒＯ＿２－Ｙ＿２Ｏ＿３纳米晶为感湿材料制作了厚膜型湿敏元件，测试结果表明：（１）元件电阻随相对湿度上升而下降。（２）在总电导中．离子电导占主要成分。（３）元件有较快的感湿响应速度。     

超负磁致伸缩晶体Sm－Fe、Sm－Dy－Fe和Sm－Dy－Fe－Al的研究

本文研究了轻稀土负磁致伸缩ＳｍＦｅ＿ｘ（１．４０＜ｘ＜１．９４），Ｓｍ＿ｘＤｙ＿（１－ｘ）Ｆｅ＿ｙ（０．８４＜ｘ＜０．９２．１．８０＜ｙ＜１．９０），Ｓｍ＿（０．９０）Ｄｙ＿（０．１０）（Ｆｅ＿（０．９５）Ａｌ＿（０．０５））＿（１．８０）晶体的制备、热处理及磁学性能，发现ＳｍＦｅ＿ｘ合金的λ－ｘ曲线存在两个峰值，峰值的ｘ点随热处理发生的变化有一定的规律性，还比较了热处理前后，Ｓｍ－Ｆｅ、Ｓｍ－Ｄｙ－Ｆｅ和Ｓｍ－Ｄｙ－Ｆｅ－Ａｌ的相组成对性能的影响。热处理用于改善磁致伸缩性能，并且制得了高磁致伸缩性能的ＳｍＦｅ＿２和（Ｓｍ，Ｄｙ）Ｆｅ＿２合金。     

薄层光电晶体的研究

本文报导了在３００～４１０℃下采用ＭＯＣＶＤ技术制备多晶（非晶和微晶）薄层氧化物ＴｉＯ＿２（Ｆｅ＿２Ｏ＿３、ＳｎＯ＿２和Ｉｎ＿２Ｏ＿３·Ｓｎ）膜的结果，这些薄层氧化物的结构、表面形态和光电化学性质采用ｘ－射线衍射、电于显微镜和三电极方法进行描述。实验指出，这些薄层从化物适宜于作为光电极的透明导电涂层和分解水的光催化。     

Al_xGa_（1－x）As外延层中Si平面掺杂的SIMS研究

利用二次离子质谱（ＳＩＭＳ）系统地研究了生长温度，Ａｌ组份ｘ值和Ａｓ＿４压强对Ｓｉδ掺杂Ａｌ＿ｘＧａ＿（１－ｘ）Ａｓ的ＳＩＭＳ深度剖面，Ｓｉ原子表面分凝和向衬底扩散的影响。实验发现，在外延生长Ｓｉδ掺杂Ａｌ＿ｘＧａ＿（１－ｘ）Ａｓ时，随着生长温度的提高或Ａｌ组份Ｘ值增加，Ｓｉ掺杂分布ＳＩＭＳ峰都非对称展宽，表面分凝作用加强，但不影响Ｓｉ原子的扩散，因此ＳＩＭＳ剖面的展宽与扩散无关。另外，我们还发现Ａｓ＿４压强高于１．５×１０￣（－５）ｍｂａｒ时，Ａｓ＿４压强对δ掺杂空间分布影响不大，而Ａｓ＿４压强低于此压强时，Ｓｉ掺杂分布峰宽度增加很快，这主要由杂质扩散作用引起。生长温度对掺杂分布峰影响最大，其次是Ａｌ组份影响，而较小Ａｓ＿４压强的影响不可忽视。这些研究结果对外延生长Ｓｉδ掺杂Ａｌ＿ｘＧａ＿（１－ｘ）Ａｓ材料是有价值的。     

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.     

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.     

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...     

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.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

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.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...