国产金属有机化合物TMGa,TMAl,TMIn和TMSb的MOVPE鉴定

利用我们研制的常压ＭＯＶＰＥ设备对国产ＴＭＧａ、ＴＭＡｌ、ＴＭＩｎ和ＴＭＳｂ进行了鉴定，为此分别生长了ＧａＡｓ、ＡｌＧａＡｓ、ＩｎＰ、ＧａＳｂ外延层和ＧａＡｓ／ＡｌＡｓ、ＧａＳｂ／ＩｎＧａＳｂ超晶格和ＧａＡｓ／ＡｌＧａＡｓ量子阱结构。表征材料纯度的７７Ｋ载流予迁移率分别达到ＧａＡｓ：μ＿ｎ＝５６６００ｃｍ￣２／Ｖ·ｓ，Ａｌ＿（０．２５）Ｇａ＿（０．７５）Ａｓ：μ＿ｎ＝５１６０ｃｍ￣２／Ｖ·ｓ，ＩｎＰ：μ＿ｎ＝６５３００ｃｍ￣２／Ｖ·ｓ，ＧａＳｂ：μ＿ｐ＝５０７６ｃｍ￣２／Ｖ·ｓ。由１０个周期的ＧａＡｓ／ＡｌＡｓ超晶格结构组成的可见光区布拉格反射器已观测到很好的反射光谱和双晶Ｘ射线回摆曲线上高达±２０级的卫星峰。ＧａＡｓ／Ａｌ＿（０．３５）Ｇａ＿（０．６５）Ａｓ量子阱最小阱宽为１０，在ｌｉＫ下由量子尺寸效应导致的光致发光峰能量移动为３９０ｍｅＶ，其线宽为１２ｍｅＶ。这些结果表明上述金属有机化合物已达到较高质量。     

δ－掺杂GaAs／AlxGa_（1－x）As二维电子气结构材料的GSMBE生长与特性

本文用ＧＳＭＢＥ技术生长纯度ＧａＡｓ和δ－掺杂ＧａＡｓ／Ａｌ_ｘＧａ_（１－ｘ）Ａｓ结构二维电子气材料并对其电学性能进行了研究。对于纯度ＧａＡｓ的ＧＳＭＢＥ生长和研究，在低掺Ｓｉ时，载流子浓度为２×１０~（１４）ｃｍ~（－３），７７Ｋ时的迁移率可达８４，０００ｃｍ~２／Ｖ．ｓ。对于用ＧＳＭＢＥ技术生长的δ－掺杂ＧａＡｓ／Ａｌ_ｘＧａ_（１－ｘ）Ａｓ二维电子气材料，在优化了材料结构和生长工艺后，得到了液氮温度和６Ｋ迁移率分别为１７３，５８３ｃｍ~２／Ｖ．５和７．６７×１０~５ｃｍ~２／Ｖ．ｓ的高质量ＧａＡｓ／Ａｌ_ｘＧａ_（１－ｘ）Ａｓ二维电子气材料。     

预非晶化离子注入对硅p^＋n结构性能的影响

用Ｓｉ＾＋／Ｂ、Ａｒ＾＋／Ｂ＾＋双注入结合快速退火技术制备出了较浅的ｐ＾＋ｎ结,用四探针法、扩展电阻法、背散射沟道谱、二次离子质谱等测试分析手段研究了Ｓｉ＾＋或Ａｒ＾＋预蜚 晶人离子注入的作用。结果表明,适当条件的Ｓｉ＾＋／Ｂ＾＋双注入制备 高硼原子电激活率的Ｐ＾＋薄层且电性能优良,残留二次缺陷少,ｐ＾＋ｎ结二极管反忖电流仅２．０ｎＡ／ｃｍ＾２（－１．４Ｖ）;而Ａｒ＾＋主虽然也能抑制硼原子注入沟道     

预非晶化离子注入对硅p~+n结性能的影响

用Ｓｉ＋／Ｂ＋、Ａｒ＋／Ｂ＋双注入结合快速热退火技术制备出了较浅的ｐ＋ｎ结,用四探针法、扩展电阻法、背散射沟道谱、二次离子质谱等测试分析手段研究了Ｓｉ＋或Ａｒ＋预非晶化离子注入的作用。结果表明,适当条件的Ｓｉ＋预非晶化注入能有效地抑制硼原子的沟道效应,用Ｓｉ＋／Ｂ＋双注入制备出了高硼原子电激活率的Ｐ＋薄层,且电性能优良,残留二次缺陷少,ｐ＋ｎ结二极管反偏漏电流仅２．０ｎＡ／ｃｍ２（－１．４Ｖ）;而Ａｒ＋注入虽然也能抑制硼原子注入沟道效应,但它使注入硼原子电激活率低,制得的Ｐ＋薄层性能差,残留二次缺陷较多     

n型GaSb,InGaAsSb的MBE生长和特性研究

本文报导了非故意掺杂ＩｎＧａＡｓＳｂ本底浓度的降低和掺Ｔｅｎ型ＧａＳｂ和ＩｎＧａＡｓＳｂ的ＭＢＥ生长与特性的研究结果。结果表明，通过生长工艺的优化，ＧａＳｂ和ＩｎＧａＡｓＳｂ的背景空穴浓度可分别降至１．１×１０~（１６）ｃｍ~（－３）和４×１０~（１６）ｃｍ~（－３），室温空穴迁移率分别为９４０ｃｍ２／ｖ．ｓ和２６０ｃｍ~２／ｖ．ｓ。用Ｔｅ作ｎ型掺杂剂，可获得载流子浓度在１０~（１６）～１０~（１８）ｃｍ~（－３）的优质ＧａＳｂ和ＩｎＧａＡｓＳｂ外延层，所研制的材料已成功地制备出Ｄ_λ~＊＝４×１０~（１０）ｃｍＨｚ~（１／２）／Ｗ的室温ＩｎＧａＡｓＳｂ红外探测器和室温脉冲ＡｌＧａＡｓＳｂ／ＩｎＧａＡｓＳｂ双异质结激光器。     

原位生长陶瓷相增强Al基复合材料的界面、微观结构及性能

本文对原位生长Ａｌ_４Ｃ_３与外加ＳｉＣ颗粒混杂增强Ａｌ（Ａｌ_４Ｃ_３·ＳｉＣ／Ａｌ）和原位生长Ａｌ_２Ｏ_３、ＴｉＢ_２颗粒混杂增强Ａｌ（Ａｌ_２Ｏ_３·ＴｉＢ_２／Ａｌ）两种复合材料的界面、微观结构和性能进行了研究。原位生长陶瓷相在基体中呈均匀分布。Ａｌ_２Ｏ_３和ＴＩＢ_２为尺寸１０ｎｍ～２μｍ的颗粒，Ａｌ_４Ｃ_３为长度０．２μｍ，直径０．０２μｍ的棒状单晶体。原位陶瓷相和Ａｌ基体之间的界面是清洁的，不存在中间过渡层。Ａｌ_４Ｃ_３和Ａｌ之间可存在的取向关系．Ａｌ_２Ｏ_３和ＴｉＢ_２粒子与Ａｌ之间不存在取向关系。两种复合材料都表现出优于ＳｉＣ_ｗ／Ａｌ复合材料的强度。     

GaInAsSb共振腔增强光电探测器设计

本文用一插值和介电常数的计算模型,得到了ＧａＩｎＡｓＳｂ四元系２．４μｍ探测器材料的 份及其折射率。将传统的Ｐ－ｉ－ｎ－ＧａＩｎＡｓＳｂ探测器结构置于两组ＡｌＡｓＳｂ／ＧａＳＢ Ｂｒａｇｇ反射镜之间,可以得到接近１的量子效率。本文用传递矩阵方法（ＴＭＭ）计算了ＡｌＡｓＳｂ／ＧａＳｂ Ｂｒａｇｇ反射镜的反射率与波长及反射镜个数的关系,并对探测器的结构进行了设计,讨论了吸收系数与波长的函数对探测器量子     

聚酰亚胺LB膜MIS结构C—V特性

本文报道了Ａｌ／ＬＢ聚酰亚胺膜／Ｐ－Ｓｉ（１００）ＭＩＳ结构的Ｃ－Ｖ特性研究结果。６７层ＬＢ膜样品Ｃ－Ｖ特性近乎理想，具有负的固定电荷密度约１０＾１＾１ｃｍ＾－＾２量级，平带时滞后小于０．３Ｖ，对于ＭＩＳ隧道结，除了在－０．５－１．５Ｖ间具有反型层箝位产生的电容峰外，在－１．５－４Ｖ间还出现了另一电容峰值，假设在强电场下隧穿能力剧增，从而结构由隧穿限制区重新进入半导体限制区，可以解释这一峰值的出现     

PECVD法淀积氮化硼薄膜场发射特性研究

用 Ｂ２Ｈ６和 ＳｉＨ４作反应气体,通过射频等离子体增强化学气相淀积（ＲＦ－ＰＥＣＶＤ）方法,在 Ｓｉ（１００）面上沉积生长ＢＮ薄膜,用Ｓ－５２０扫描电子显微镜对所得薄膜进行观测,并用红外透射光谱测试分析了膜的成分。在室温、压力为 ８ × １０－４ Ｐａ条件下,对 ＢＮ薄膜的电流一电压特性进行测量,并得到了 Ｆｏｗｌｅｒ－Ｎｏｒｄｈｅｉｍ特性曲线,ＢＮ膜的场发射开启电场为９ Ｖ／μｍ,在电场３７．５ Ｖ／μｍ时,电流密度达到２４．８ ｍＡ／ｃｍ２。     

以Ba云母为主晶相的可切削玻璃陶瓷

基于Ｂａ０．５Ｍｇ３（Ｓｉ３ＡｌＯ１０）Ｆ２－Ｍｇ２Ａ１４Ｓｉ５Ｏ１８－Ｃａ３（ＰＯ４）２系统，制备出了以含Ｂａ碱士云母为主晶相的可切削玻璃陶瓷，弯曲强度σｂ＝２２９ＭＰａ，断裂韧性Ｋｌｃ＝２．４８ＭＰ·ｍ１／２；钻孔速度大于７ｍｍ／ｍｉｎ．优良性能的获得借助于Ｂａ云母玻璃陶瓷可控的显微组织，即相互交错的云母体和“卷心菜”的组织特征．观察到了两类类型的断口形貌：云母晶体层内断的层状花样和沿（００１）晶面层间断的小刻面花样．     

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.     

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     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to