在GaAs(100)衬底上离化团束外延ZnSe单晶薄膜

ZnSe是一种理想的蓝紫色发光材料，用于制作发光器件有较大的应用前景，采用单源喷发、离化原子团束（ICB）技术在GaAs（100）上外延ZnSe单晶薄膜，并用电子能谱分析了外延薄膜的成分。用X射线衍射和RHEED研究了外延ZnSe单晶薄膜结构和外延质量。研究了淀积能量和衬底温度对薄膜质量的影响。得到了摆动曲线半高宽为133rad·s，并具有原子水平平整程度的ZnSe（100）单晶薄膜。外延薄膜存在0．2～0．4μm的应变过渡层，过渡层随淀积能量的增大而变薄。     

利用UHV／CVD技术在双层多孔硅上外延硅研究

利用ＵＨＶ／ＣＶＤ技术，在较低的温度下，在阳极氧化形成的双层多孔硅上，成功地生长了单晶性好、厚度均匀、电阻率分布合适的硅单晶外延层。这为进一步研制了ＳＯＩ材料与器件提供了所需的薄硅外延层。     

异质外延MgO/SrTiO3薄膜中界面应力研究

本文利用激光分子束外延(LMBE)技术在SrTiO3(100)单晶基片上外延生长MgO薄膜，同时又在MgO(100)单晶基片上外延生长SiO3(STO)薄膜。通过反射高能电子衍射(RHEED)仪原位实时监测薄膜生长，研究薄膜的生长过程。并结合X射线衍射(XRD)仪来分析在不同的生长条件下，不同应力对薄膜外延生长的影响。在压应力情况下，MgO薄膜在STO基片上以单个晶胞叠层的方式生长，即以“Cubicon Cubic”方式进行外延；在张应力情况下，由于膜内位错较多，STO薄膜在MgO基片上以晶胞镶嵌的方式进行生长，即以“Mosaic”结构进行外延；提高生长温度，可以减少膜内位错，提高外延质量，使STO薄膜在MgO基片上以较好的层状方式外延生长。     

单晶Tm2O3高k栅介质漏电流输运机制研究

利用分子束外延技术在p型Si(001)衬底上外延生长了单晶Tm2O3高k栅介质薄膜,分别在不同温度下测量了薄膜的电流-电压特性。基于变温电流-电压特性数据的漏电流输运机制分析表明,单晶Tm2O3栅介质薄膜在正偏压下的主要漏电流输运机制为肖特基发射,而在负偏压下的主要漏电流输运机制为Frenkel-Poole发射。     

α—Al2O3衬底上生长的GaN膜的光学性质

采用金属有机化学气相淀积方法生长了α－Ａｌ２Ｏ３衬底上外延的高质量的单晶ＧａＮ薄膜。Ｘ射线衍射光谱与喇曼散射光谱表征了ＧａＮ外延薄膜的单晶结构和单晶质量。透射光谱和光调制反射光谱定出了六角单晶ＧａＮ薄膜的直接带隙宽度和光学参数。     

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.     

α－Al_2O_3衬底上生长的GaN膜的光学性质

采用金属有机化学气相淀积（ＭＯＣＶＤ）方法生长了α－Ａｌ２Ｏ３衬底上外延的高质量的单晶ＧａＮ薄膜。Ｘ射线衍射光谱与喇曼散射光谱表征了ＧａＮ外延薄膜的单晶结构和单晶质量。透射光谱和光调制反射光谱定出了六角单晶ＧａＮ薄膜的直接带隙宽度和光学参数。     

c轴取向PbTiO3外延生长的研究

本文研究了ＭＯＣＶＤ法淀积过程中工艺条件对ＰｂＴｉＯ３膜ｃ轴取向度的影响，探讨了ＰｂＴｉＯ３膜的生长过程，通过调节氧气流量首次在ＭｇＯ（１００）单晶衬底上淀积出ｃ轴取向的ＰｂＴｉＯ３外延膜。ＰｂＴｉＯ３外延膜的介电常数为９０，折射率为２．６４，均和单晶性能一致。     

多孔硅外延层转移制备SOI材料的研究

用多孔硅外延层转移的方法成功地制备出了SOI材料，卢瑟福背散射／沟道谱（RBS／C）和扩展电阻（SPR）的结果表明获得的SOI材料上层硅具有很好的单晶质量，电阻率分布均匀，上层硅与氧化硅埋层界面陡直。对制备多孔硅的衬底材料也作了研究，结果表明P型重掺杂的硅衬底在暗场下阳极氧化后仍保持很好的单晶性能，用超高真空电子束蒸发方法能外延出质量很好的单晶硅，并且，在一定浓度的HF／H2O2溶液中具有较高的腐蚀选择率，保证了上层硅厚度的均匀性。     

PbTe单晶薄膜的热壁外延

介绍了一种简单的HWE装置和利用这一装置在BaF_2(111)面上生长PbTe单晶外延层的工艺。扫描电镜、X-光衍射和霍尔测量表明,PbTe单晶外延层是完美的。     

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.     

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.     

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 ...     

Effect of Oxide Assisted Metal Nanoparticles on Microstructure and Morphology of Gallium oxide Nanowires

Several researches have been reported about the characteristic of β-Ga2O3 nanowires which was synthesized on nickel oxide particle. But indeed, recent researches about synthesis of β-Ga2O3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst. In this work, Gallium oxide (β-Ga2O3 ) nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700 - 1000℃ using the iron, nickel, copper, cobalt and zinc oxide as a catalyst, respectively. The β-Ga2O3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850, 900 and 950℃ in all the catalysts. But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst. As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods, and its diameter increased. From these results, we could be proposed that the growth mechanism of β-Ga2O3 nanowires was changed with synthesis temperature of nanowires. Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM, FE-SEM, EDX and XRD.     

The Influence of Nitrogen and Boron Implant into Silicon Substrate on the Phase and Internal Stress of c-BN Films

Cubic boron nitride(c-BN) film was deposited on a Si (100) substrate by the RF-magnetron sputtering.The mainly problems for fabrication of c-BN films are the low purity and high intrinsic compressive stress. In order to solve the two problems, the c-BN film with the buffer interlayer was deposited on the substrate which had been implanted with nitrogen and/or boron ions. The results show: the implantation of nitrogen ions can obviously increase c-BN content and reduce the internal stress slightly; while the implantation of boron shows no obvious improvement to the content of c-BN, which can reduce the internal stress in the film obviously. In addition, it is suggested that the implantation of nitrogen and boron shows the best result, which not only can increase the content of c-BN, but also reduce the internal stress in the c-BN film obviously.