实用化GaInP—AlGaInP半导体量子阱可见光激光器

用低压ＭＯＶＰＥ方法研制出了波长为６５５ｎｍ与６７０ｎｍ的ＧａＩｎＰ－ＡｌＧａＩｎＰ半导体量子阱可见激光器，并已形成一定的批量生产能力。器件的阈值电流典型值为４５ｍＡ，输出光功率不小于５ｍＷ，最高工作温度不低于５０℃，预计２０℃时寿命接近１００，０００小时，主要技术指标与目前进口的同类产品水平相当，完全可以满足实用要求。     

氧在GaAs／GaInP／AlGaInP中的SIMS分析

用ＳＩＭＳ对用于可见光激光器研制的ＧａＡｓ／ＧａＩｎＰ／ＡｌＧａＩｎＰ材料系统进行了测试分析。适当选择质量特征峰，不仅清晰地展示出这种材料系统的结构，而且对非有意掺入的有害杂质氧进行监测，及时发现了工艺系统中的气和源的质量问题。对在不同实验条件下制备的多批样品的ＳＩＭＳ分析表明，氧含量的判别在一个数量级以上，氧含量的高低直接影响激光器的性能指标和寿命。为改进工艺和源的质量提供了可靠的依据。     

用于掺铒光纤放大器泵浦源的高性能980nm InGaAs应变量子阱激光器

利用分子束外延方法研制出了高质量的ＩｎＧａＡｓ／ＡｌＧａＡｓ庆变量子阱激光器外延材料，其最低的阈值电流密度可达到１２０Ａ／ｃｍ＾２，激光波长在９８０ｎｍ左右。获得了高性能的适合于掺铒光纤放大器用的９８０ｎｍ量子阱激光器泵浦源，其典型的阈值电流为１５ｍＡ，外微分量子效率的典型值和最好值分别为０．８ｍＷ／ｍＡ和１．０ｍＷ／ｍＡ，线性输出功率大于１２０ｍＷ，在２０℃－５０℃的特征温度Ｔ０为１２５Ｋ。器件     

Al,Ga取代Bi：DyIG薄膜的磁和磁光特性的研究

本文报道用热分解法在玻璃衬底上制备了Ａｌ和Ｇａ取代的Ｂｉ：ＤＹＩＧ薄膜，对其磁和磁光特性做了详细研究．Ａｌ和Ｇａ取代的薄膜均可获得好的矩形比和高的矫顽力．对于Ｂｉ１．２Ｄｙ１．８Ｆｅ５－ｘＭＸＯ１２（Ｍ＝Ａ１，ＧＺ）薄膜，Ａ１和Ｇ２的最佳替代成份分别为１．０和Ｇ．７；最佳晶化温度分别为７００ｏ℃和６７５℃．在波长５１０ｎｍ附近，法拉第旋转角可达８°／ｕｍ左右．光学吸收和品质因子的研究结果表明，Ａｌ和Ｇａ取代能够影响光学吸收和品质因子，其中Ｇａ取代对光学吸收和品质因子的影响较大．     

GaN光导型紫外探测器

研究了以金属有机物化学气相沉积方法生长在６Ｈ－ＳｉＣ衬底上的ＧａＮ光导型紫外探测器的光电流性质。通过光电流谱的测量，获得了ＧａＮ探测器在波长２５０ｎｍ－３６０ｎｍ范围近于平坦的光电流响应，并且观察到在３６５ｎｍ（￣３．４ｅＶ）带边附近陡峭的截止边。测得ＧａＮ探测器在５Ｖ偏压下在３６０ｎｍ波长处的光电流响应度为１３３Ａ／Ｗ，并得到了其响应度与外加偏压的关系。通过拟合光电信号强度与入射光调制频率的实验     

连续输出20WAlGaAs／GaAs量子阱激光二极管线列阵

采用ＭＯＣＶＤ实现了ＡｌＧａＡｓ／ＧａＡｓ量子阱结构，获得了连续输出２０Ｗ激光二极管线列阵，线列阵长度１．０ｃｍ，激射波长８０８±４ｎｍ。     

共沉淀法制备YAG-Al2O3纳米复合粉体

本文采用共沉淀法制备了ＹＡＧ－Ａｌ_２Ｏ_３纳米复合粉体．并通过ＸＲＤ、ＴＥＭ详细研究了粉体组成、形貌随煅烧温度的变化．研究表明,在１３００℃下煅烧可获得ＹＡＧ粒径约１００ｎｍ、分散均匀、无杂相的ＹＡＧ－Ａｌ_２Ｏ_３纳米复合粉体．粉体在１４５０℃可热压烧结致密,远低于文献报道的热压烧结温度１６００℃．用共沉淀法制备ＹＡＧ－Ａｌ_２Ｏ_３纳米复合粉体具有成本低、产量高和工艺简单的优点．     

IBAD薄膜与基体界面的显微结构

采用中能离子束辅助沉积（ＩＢＡＤ）技术，在单晶Ａｌ２Ｏ３（０００１）基片上沉积Ｍｏ膜，在ＧＡＡｓ（００１）基片上合成Ｆｅ１６Ｎ２薄膜，用ＨＲＥＭ等研究了Ｍｏｅａｊｄ－Ａｌ２Ｏ３（０００１），Ｆｅ１６ｎ２膜－ＧａＡｓ（００１）界面的显微结构，结果表明：Ｍｏ膜的晶粒呈细小柱状或纤维状，晶粒平均尺寸约８ｎｍ，Ｆｅ１６Ｎ２薄膜为等轴晶，晶粒平均尺寸约为１０ｎｍ，在Ｍｏ膜－Ａｌ２Ｏ３（０００１）界面及Ｆｅ１     

Ge/GaAs中APD及薄膜性能研究

研究了一种光纤通讯用光电探测器。在ＧａＡｓ上蒸镀８００ｎｍ的Ｇｅ,并在此材料基础上提出了一种吸收倍增分离的雪崩二极管（ＳＡＭ－ＡＰＤ）的结构设计,采用ＧａＡｓ作为倍增区,Ｇｅ作为吸收区。在此结构上初步制作的二极管正向开启电压为０．２￣０．３Ｖ,反向击穿电压为２．５Ｖ,漏电不明显,ｐ－ｎ结特性良好。     

纳米GaAs—SiO2镶嵌复合薄膜的制备

利用射频磁控共溅法制备了纳米ＧａＡｓ－ＳｉＯ２镶嵌复合薄膜，通过Ｘ射线衍射，透射电镜和Ｘ射线光电子能谱等手段研究了薄膜的结构及其与沉积时基片温度间的关系，结果表明，薄膜由晶态的ＧａＡｓ及非晶ＳｉＯ２组成，ＧａＡｓ在沉积过程中未明显氧化，且以纳米颗粒形成的均匀地弥散在ＳｉＯ２中；ＧａＡｓ的平均粒径依赖于沉积时的基片温度，获得了ＧａＡｓ的平均粒径在３～１０ｎｍ的ＧａＡｓ→ＳｉＯ２镶嵌复合薄膜。     

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.……     

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.     

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 ...