磁控溅射制备(Pb1-xSrx)TiO3系铁电薄膜的实验研究

钛酸锶铅((Pb1-xSrx)TiO3,PST)固溶体材料是一种性能优良的钙钛矿型铁电材料,其形成铁电相的温度较低,且易于和半导体工艺结合,应用潜力较大.本文采用磁控溅射法制备了PST薄膜,并初步研究了其介电和铁电特性.结果表明,磁控溅射得到的PST薄膜必须进行一定的热处理,才能使之转变为具有铁电性的钙钛矿结构的铁电薄膜.其介电特性与测试频率有关,试样的饱和极化强度可达19μC/cm2,剩余极化强度可达6.6μC/cm2,矫顽场强达16kV/cm,热释电系数达10-4C/m2*K量级,表明所制备的PST薄膜具有良好的铁电性.     

磁控溅射制备(Pb_(1-x)Sr_x)TiO_3系铁电薄膜的实验研究

钛酸锶铅 ((Pb1 -xSrx)TiO3,PST)固溶体材料是一种性能优良的钙钛矿型铁电材料 ,其形成铁电相的温度较低 ,且易于和半导体工艺结合 ,应用潜力较大。本文采用磁控溅射法制备了PST薄膜 ,并初步研究了其介电和铁电特性。结果表明 ,磁控溅射得到的PST薄膜必须进行一定的热处理 ,才能使之转变为具有铁电性的钙钛矿结构的铁电薄膜。其介电特性与测试频率有关 ,试样的饱和极化强度可达 19μC cm2 ,剩余极化强度可达 6 6 μC cm2 ,矫顽场强达 16kV cm ,热释电系数达10 - 4 C m2 ·K量级 ,表明所制备的PST薄膜具有良好的铁电性。     

磁控溅射制备（Pb1—xSrx）TiO3）系铁电薄膜的实验研究

钛酸锶铅（Pb1-xSrx)TiO3,PST)固溶体材料是一种性能优良的钙钛矿型铁电材料,其形成铁电相的温度较低,且易于和半导体工艺结合,应用潜力较大,本采用磁控溅射法制备了PST薄膜,并初步研究了其介电和铁电特性,结果表明,磁控溅射得到的PST薄膜必须进行一定的热处理,才能使之转谈具有铁电性的钙钛矿结构的铁电薄膜,其介电特性与测试频率有关,试样的饱和极化强度可达19uC/cm2,剩余极化强度可达6．6uC/cm2,矫顽场强达16kV/cm,热释电系数达10^-4C/m2.K量级,表明所制备的PST薄膜具有良好的铁电性。     

溅射气氛对所制备PST/Si薄膜性能的影响

采用高频磁控溅射法制备了Si基(Pb1-xSrx)TiO3系铁电薄膜(以下简称PST/Si)。实验表明,合适的Ar、O2分压比,能保证溅射时挥发出的Pb及时与补充的O离子得以充分化合,确保制备所需成份的PST薄膜。O2分压过高,Au电极中将有大量的O离子严重渗透,从而使PST薄膜介电损耗增加并降低其极化能力。实验中Ar、O2比为5∶1的PST/Si样品性能较好,其介电损耗约在0.12~0.21之间,热释电系数约为2.35×10-2μC/cm2K。     

硅基三元系PMnN-PZT铁电薄膜制备与研究

利用磁控溅射方法在单晶Si基底上沉积三元系铁电薄膜6%PMnN-94%PZT(6%Pb(Mn1/3,Nb2/3)O3-94%Pb(Zr0.52,Ti0.48)O3),采用淬火方法对薄膜进行处理,以促进薄膜钙钛矿结构形成。同时,在相同条件下制备非掺杂PZT(52/48)薄膜以对比薄膜掺杂效果。运用X射线衍射(XRD)技术分析薄膜晶向及晶体结构,运用Sawyer Tower电路测试薄膜铁电性能,运用激光测振仪测试薄膜的压电系数。实验结果表明,所沉积薄膜为多晶钙钛矿结构铁电薄膜,薄膜铁电剩余极化Pr=23.7μC/cm2,饱和极化Ps=40μC/cm2,矫顽场电压2Ec=139kV/cm,横向压电系数e11=-13.2C/m2,薄膜的铁电及压电性能优良。     

紫光对多晶掺锰铁酸铋薄膜铁电和电输运性质的影响

采用溶胶-凝胶的方法在Pt(111)/Ti/SiO2/Si(001)基片上制备了5％Mn掺杂的BiFeO3(BFMO)薄膜,并构建了Pt/BFMO/Pt对称型电容器,研究了紫光对多晶BFMO薄膜铁电性及J-V特性的影响.实验发现,在紫光的照射下,薄膜的电导增大,这是由于紫光入射在BFMO薄膜上,产生了光生我流子.当外加电压为5V时,漏电流密度由9.1mA/cm2增大到16.3mA/cm2.Pt和BFMO的接触满足金属-半导体理论中的欧姆接触,并且光的存在并没有改变Pt/BFMO/Pt电容器的漏电流机制.当光入射到薄膜表面,样品的剩余极化强度增大,由无光时的91.7μC/cm2增大到光照时的99.9μC/cm2.     

Sol-gel方法制备BiFeO_3/Bi_4Ti_3O_(12)多层薄膜及其电性能

采用溶胶-凝胶方法在FTO/glass底电极上制备了BiFeO3/Bi4Ti3O12和Bi4Ti3O12/BiFeO3多层薄膜。研究了室温下薄膜的结构,铁电性质和介电性质,并将其与纯的BiFeO3薄膜的性质进行了比较。从薄膜的XRD模式中可以观察到共存的BiFeO3相和Bi4Ti3O12相。通过电滞回线测量可以看出,相对于纯的BiFeO3薄膜,BiFeO3/Bi4Ti3O12和Bi4Ti3O12/BiFeO3多层薄膜能够承受更高的测试电场而获得充分极化,从而表现出较强的铁电性,在450kV/cm测试电场下,薄膜的剩余极化强度分别为37μC/cm2和23μC/cm2。     

磁控溅射制备PST薄膜的介电与铁电性能

（Pb1-xSrx）TiO3系铁电材料是一种互溶性较好的钙钛矿材料，本文采用磁控溅射法，在Si基底上成功地制备了结构致密、性能优良的PST铁电薄膜，其制备工艺可与Si微电子技术兼容。性能测试表明，其介电常数可达900，接近10^3量级，介电损耗较低，约在0．12-0．21之间（-10℃至60℃）。铁电性能也较好，其饱和极化强度可接近10μC／cm^2，矫顽场强约21kV／cm。     

退火温度对Sol-gel法制备的BiFeO3薄膜结构及电性能的影响

采用溶胶-凝胶法在ITO/glass衬底上制备了BiFeO3薄膜,退火温度分别为500℃和550℃.实验结果表明,550℃退火的薄膜晶粒较大且不均匀,并有杂相产生,薄膜的漏电流较大,没有得到饱和的电滞回线;而在500℃退火的薄膜晶粒较小且均匀,没有杂相产生,相对于550℃退火的薄膜,其漏电流密度降低了约2个数量级,铁电性得到明显增强,剩余极化强度约为40μC/cm2,矫顽场约为75kV/cm,最大的测试电场为130kV/cm.     

Pb(Hf_(0.3)Ti_(0.7))O_3铁电薄膜的制备与性能研究

采用脉冲激光沉积方法在不同温度下生长Pb(Hf0.3Ti0.7)O3(PHT)铁电薄膜,利用各种表征手段测试并分析薄膜的微观结构和电性能。研究表明,生长温度为400℃沉积的PHT薄膜具有良好的(111)择优取向;PHT薄膜矫顽场(2Ec)为390 kV/cm,剩余极化强度(2Pr)为53.1μC/cm2,经1.5×109次翻转后剩余极化强度保持85%;PHT薄膜绝缘性能良好,相对介电常数约为540。PHT薄膜有望应用于铁电随机存储器。     

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 ...