BST类铁电薄膜低温外延层状生长研究

利用激光分子束外延技术(LMBE)在SrTiO₃(100)单晶基片上外延生长SrTiO₃(STO)、BaTiO₃(BTO)、Ba_0.6Sr_0.4TiO₃(BST)铁电薄膜.通过反射高能电子衍射(RHEED)实时监测薄膜生长,并结合原子力显微镜(AFM)分析薄膜的生长模式,根据RHEED衍射强度振荡曲线及衍射图样的变化确定动态和静态控制最低晶化温度,发现STO、BTO、BST三种铁电薄膜可以分别在280、330、340℃的低温下实现外延层状生长.     

超高真空中SrTiO3薄膜同质外延生长的过程研究

在超高真空下利用激光分子束外延(LMBE)方法基于SrTiO3(100)单晶基片同质外延SrTiO3薄膜.通过反射式高能电子衍射(RHEED)对生长过程进行原位监测,发现对基片的预热处理明显有利于改善其晶面结构,当在其上同质外延SrTiO3薄膜时,容易实现单晶层状生长模式,并得到原子级平整度的铁电薄膜.     

脉冲激光沉积制备外延Ni_(0.8)Zn_(0.2)Fe_2O_4薄膜的应变与磁性能研究

用脉冲激光沉积设备,分别在SrTiO3(001)(STO)和MgO(001)基片上外延生长了单层Ni0.8Zn0.2Fe2O4(NZF)薄膜。经X射线衍射分析,在STO和MgO基片上制备的NZF薄膜均为单一c取向的外延薄膜,由PHI扫描可知薄膜均为四重对称结构。由NZF薄膜的倒易空间图可以计算得到在STO和MgO基片上应变分别为0.0704和-0.0124。分别对不同基片上的NZF薄膜进行磁强计测量可得,在STO基片上沉积的NZF薄膜的面内和面外饱和磁化强度分别为269.6和224.78 emu/cm3,面内和面外的矫顽场分别为2.68×104和4.78×104A/m,在MgO基片上沉积的NZF薄膜的面内和面外饱和磁化强度分别为219.11和180.75 emu/cm3,面内和面外的矫顽场分别为3.46×104和5.32×104A/m。     

外延薄膜生长的实时监测分析研究

利用反射式高能电子衍射(RHEED)在超高真空中对SrTiO3(100)、LaAlO3(100)、Si(100)单晶基片进行分析,讨论了衍射花样与晶体表面结构的对应关系,计算出表面的晶体学参数,同时采用激光分子束外延技术同质外延生长SrTiO3薄膜，根据RHEED衍射图样及强度振荡曲线实时监控薄膜的生长。     

PLZT（28／0／100）薄膜的溶胶—凝胶制备技术及显微结构

用溶胶—凝胶技术及回旋法,在石英玻璃和单晶si基片上制备PLZT(28/0/100)多晶薄膜;在SrTiO3和α-A12O3单晶基片上外延生长择优取向薄膜.其外延关系分别为(100)PLZT(28/0/100)//(100)SrTiO3和(100)PLZT(28/0/100)//(0001)Al2O3.用IR,XRD.RHEED,SEM和SIMS分析凝胶中杂质、凝胶的分子结构和薄膜的显微结构.结果表明,用溶胶—凝胶技术能制备出显微结构良好的多组份陶瓷薄膜.     

BST类铁电薄膜的最低晶化温度和自装生长研究

利用激光分子束外延技术(LMBE)在Si(111)、SrTiO3(100)单晶基片上在(10-5pa)高真空环境中外延生长SrTiO3(STO)、BaTiO3(BTO)、Ba0.6Sr0.4TiO3(BST)铁电薄膜.通过反射高能电子衍射(RHEED)实时监测薄膜生长,并结合原子力显微镜(AFM)分析薄膜的生长模式.根据RHEED衍射强度振荡曲线及衍射图样的变化确定动态和静态最低晶化温度,发现STO、BTO、BST三种铁电薄膜可以分别在280℃、330℃、340℃的低温下实现外延层状生长.当保持BTO(110)/Si(111)层状生长,逐渐降低沉积速率时,发现这种层状模式中每层高度是由整数倍单胞堆积而成,并且随着沉积速率从0.017nm/s降低到0.005nm/s时,每层高度由9降低到1个BTO单胞构成,这对由ABO3钙钛矿材料自组装形成纳米结构具有重要意义.     

纳米晶粒受控生长抑制PZNT铁电薄膜中异相形成

在LaAlO3（001）、MgO（001）、SrTiO3（001）衬底以及SrTiO3（001）／PZT（001）种膜上用液相外延方法生长了PZNT薄膜。生长结果表明：在LaAlO3（001）基片PZNT晶粒以三维岛状自发生长。薄膜中有大量的焦绿石异相；在MgO（001）和SrlriO3（001）衬底上，为三维岛状异质外延生长。薄膜中焦绿石异相几乎消失；引入[001]取向的PZT种膜后，岛状三维生长变为二维生长，显著改善了外延膜的质量，获得了完整的PZNT膜。分析了衬底取向对紧邻层纳米尺寸范围的晶粒形成、薄膜晶粒的发育、克服薄膜中异相形成等的影响，总结了获得完整PZNT薄膜的生长条件。     

激光分子束外延BaTiO3/SrTiO3超晶格的晶格应变研究

采用脉冲激光分子束外延(PLMBE)方法,通过优化的工艺参数,在SrTiO3(100)单晶基片上外延结构为(8/8)的BaTiO3/SrTiO3超晶格薄膜.综合利用反射式高能电子衍射系统(RHEED)、高分辨率X射线衍射(HRXRD)以及高分辨率透射电镜选区电子衍射(SAED)技术,研究超晶格薄膜的晶格应变现象和规律.研究结果表明,在制备的BaTiO3/SrTiO3超晶格薄膜中,BaTiO3晶胞面外晶格增大,面内晶格减小;而SrTiO3晶胞面内及面外方向晶格都被拉伸,但面外晶格拉伸程度较大,SrTiO3晶胞产生了与BaTiO3晶胞方向一致的四方相转变.     

PLD方法制备CaCu3Ti4O12薄膜结构研究

采用脉冲激光沉积法(PLD)分别在LaAlO3(100)以及MgO(100)基片上,在不同的沉积温度下,制备具有体心立方类钙钛矿结构的CaCu3Ti4O12(CCTO)薄膜.在LAO基片上生长的CCTO薄膜,X射线衍射(XRD)分析表明沉积温度在680℃以上可以实现 (400)取向生长,740℃薄膜可以实现cubic-on-cubic的方式外延生长.原子力显微镜(AFM)和扫描电子显微镜(SEM)分析分别显示CCTO薄膜的表面平整,界面清晰.后位的反射高能电子衍射(RHEED)观察到CCTO薄膜的电子衍射图谱,为点状.在MgO基片上,由于薄膜与基片较大的晶格失配,通过生长具有(100)和(110)取向的LaNiO3(LNO)缓冲层,诱导后续生长的CCTO薄膜随着温度的提高,由(220)取向生长转变成(220),(400)取向生长.     

氧化物异质外延薄膜生长的计算机模拟

利用Monte Carlo方法分别模拟了在SrTiO3基底上沉积MgO薄膜和在MgO基底上沉积SrTiO3薄膜.模拟中,选取与实验中薄膜生长相近的参数条件,引入了新的参数扩散势垒,得到了在晶格正失配(张应力)和负失配(压应力)下薄膜生长的形貌图以及薄膜粗糙度的变化曲线图,分析了张应力和压应力对薄膜生长形貌的影响.模拟结果与文献报道的外延薄膜生长模式的实验观察结果一致.     

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.……     

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...     

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.     

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.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from