高性能2.5Gb／s用的DFB—LD／EA单片集成器件

报导了采用全ＭＯＣＶＤ生长的１．５５μｍ的单片集成ＤＦＢ＝ＬＤ／ＥＡ组件的 在ＤＷＤＭ系统上的传输测试结果，出纤功率Ｐｆ≥２．５ｍＷ＠Ｉｆ＝７５ｍＡ，边模抑制比ＳＭＳＲ〉３５ｄＢ，调制器反向偏压为２．５Ｖ时的消光比为１４ｄＢ，该发射模块在２．５Ｇｂ／ｓＤＷＤＭ系统上进行了传输试验，传输２４０Ｋｍ后无误码，其通道代价≤１ｄＢ＠ＢＥＲ＝１０＾－１２。     

8频道151公里全光波分复用准工程化光纤通信系统

拥有８个频道、传输距离为１５１公里、使用二个光纤放大器和工程化端机的全光波分复用光纤通信系统在北京大学研制成功。该系统在长期工作状态下各频道的误码率在１．６×１０（－１２）至０×１０（－１５）（即单频道连续测量１５天无误码）之间。该系统使用计算机对波长进行智能控制并监视该系统的工作状态。各频道波长分别是１５３１ｎｍ，１５３３ｎｍ，１５３５ｎｍ，１５３７ｎｍ，１５３９ｎｍ，１５４３ｎｍ，１５４５ｎｍ和１５４９ｎｍ。每频道传输码率为１４０Ｍｂ／ｓ，传输码型为１Ｂ１ＨＣＭ１ＰＲＢＳ。因此该系统总传输码率可以达到２．２Ｇｂ／ｓ（即２８０Ｍｂ／ｓ×８）。经过长时间开机检测，该系统已经接近于工程使用要求。     

4×155Mb／s频分复用（FDM）光纤通信系统的研究

报道了一个无故障工作时间大于２４小时的四路１５５Ｍｂ／ｓ频分复用（ＦＤＭ）光纤通信系统，实测系统误码率优于０×１０（－１４）。系统接收机包括解复用光滤波器，接收机灵敏度优于－３０ｄＢｍ（ＢＥＲ＝１×１０（－９），频道间距为０．１ｎｍ，四路ＦＤＭ信号－２０ｄＢ的总谱宽为０．７ｎｍ。系统采用国产ＤＦＢ激光器为光源，实际光纤传输距离１８ｋｍ。系统全部实现了脱离光学平台的模块化结构，在长期的系统实验中显示了优良的稳定性。这一成果为ＦＤＭ在光纤传输接入网中的进一步实用化开发铺平了道路。     

调顶技术及其在波分复用光纤通信系统中的应用

给出了调顶技术对光纤通信系统误码特性影响的简单理论估计和实测结果：调顶深度小于５％时,调顶对系统接收机灵敏度的影响小于０．５ｄＢ。将专门研制的实用化调顶盘和解调顶盘用于实际的８信道ＷＤＭ光纤通信系统中,能准确判断各信道的有无及其光功率的相对变化,并据此实现了ＥＤＦＡ的增益箝制。     

HL—1M装置硼化壁的出气特性

借助ＱＭＳ诊断技术，完成了ＨＬ－１Ｍ装置Ｂ／Ｃ壁和Ｓ壁的出气特的对比实验研究。Ｂ／Ｃ壁的最大出气率是２．６０×１０＾２０ｍｏｌ／ｓ其中Ｈ２占９９．６％杂质组分３．８×１０＾－３。与ＳＳ壁相比，Ｂ／Ｃ壁的Ｈ２出气率增加了１．３倍，杂质组分出气率小一个量级，且气体的动力学滞留时间得到增强。     

磷酸盐陶瓷Ca_(1-x)Ba_xZr_4(PO_4)_6的制备及其零膨胀组成的耐热冲击性研究

Ｃａ１－ｘＢａｘＺｒ４（ＰＯ４）６（０≤ｘ ≤１,简称ＣＢＺＰ）是由具有相反热膨胀异向性的 ＣａＺｒ４（ＰＯ４）６和ＢａＺｒ４（ＰＯ４）６互溶形成的二元固溶体型ＮＺＰ族陶瓷,其热膨胀系数具有可裁剪性．本研究的主要目的是通过调整组成,制备具有较好耐热冲击性的零膨胀材料．为此,首次用共沉淀法合成了单相的 ＣＢＺＰ系列粉体。分别添加 ３％ＺｎＯ和 ４％ＭｇＯ为烧结助剂,制成Ｔ ＣＢＺＰ系列陶瓷材料,用热机械分析（ＴＭＡ）压缩法测定了试样在２０～１０００℃的平均线膨胀系数ａ２０／１０００,以及加热（２０～１０００℃）和冷却（１０００～４００℃）过程的热膨胀曲线．实验结果表明,添加 ＺｎＯ和 ＭｇＯ时的近零膨胀材料分别为Ｃａ０．８５Ｂａ０．１５Ｚｒ４（ＰＯ４）６（ｘ＝０．１５）和ＣａＺｒ４（ＰＯ４）６（ｘ＝０）,α２０／１０００依次为 ０．６×１０－６／°Ｃ和一０．８×１０－６／°Ｃ,但热膨胀曲线上却由于微裂纹的产生而呈现出较大的滞后环,耐热冲击性不理想．可见,对ＣＢＺＰ系列而言,调整组成虽然能实现零膨胀,但很难消除热膨胀异向性,提高其耐热冲击性的有效途径可能是适当抑制晶粒生长以避免产生过多的微裂纹．     

抑制等信道间距陆上干线光纤通信系统中光纤色散和四波混频效应的新方案

提出了一种用以克服等信道间距划分、波分复用（ＷＤＭ）＋掺饵光纤放大器（ＥＤＦＡ）陆上光纤通信系统中光纤色散和四波混频（ＦＷＭ）效应的新方案。采用１５５０ｎｍ处色散为－２．８９ｐｓ／ｋｍ／ｎｍ的小色散单模光纤（ｓｍａｌｌ－ｄｉｓｐｅｒｓｉｏｎｓｉｎｇｌｅ－ｍｏｄｅ－ｆｉｂｅｒ，ＳＤＳＭＦ）可避免严重的ＦＷＭ效应，同时利用ＩＴＵ－ＴＧ．６５２非色散位移光纤（ｎｏｎ－ｄｉｓｐｅｒｓｉｏｎ－ｓｈｉｆｔｅｄｆｉｂｅｒ，ＮＤＳＦ），在ＥＤＦＡ整个带宽范围内（１５３０～１５７０ｎｍ）补偿ＳＤＳＭＦ引入的负色散。采用此方案，一个１０路×１０Ｇｂ／ｓ、１０级ＥＤＦＡ级联的等信道间距（１ｎｍ）光纤通信系统，经近千公里的光纤传输后，ＦＷＭ和色散引入的恶化量将分别小于１ｄＢ。     

10频道“波分复用＋光纤放大器”全光通信实验系统

在国内首次研制了使用１个光纤放大器的１０频道１０２ｋｍ无再生中继“ＷＤＭ＋ＥＤＦＡ”全光光纤传输实验系统。每频道传输码率为１４０Ｍｂ／ｓ或２８０Ｍｂ／ｓＮＲＺ。所用光纤放大器为增益平坦型，小信号增益为３５ｄＢ。系统全部采用国产ＤＦＢ激光器，各频道波长分别为１５３１、１５３５、１５３７、１５４５、１５４７、１５４９、１５５１、１５５９、１５６１ｎｍ，在波长为１５５１ｎｍ的频道内布置了２路频分复用（ＦＤＭ）系统。波长分布遍及整个光纤放大器的通带。经无再生中继传输１０２ｋｍ后，在误码率为１×１０￣（－９）条件下，实测了尚有数ｄＢ以上（最大为１２ｄ８）的功率裕量。系统使用光栅合、分波器作为波分复用和解复用器，频道间隔为２ｎｍ及其整数倍，系统具有１８个频道的能力。     

FeCuNbVSiB纳米晶软磁合金及其在电力电子技术领域中的应用

报道了新开发的Ｆｅ７３．２Ｃｕ０．８Ｎｂ２Ｖ１．５Ｓｉ１．５Ｂ１１纳米晶合金的主要磁性能：μ０≥８×１０＾４,ＢＳ＝１．４０Ｔ,Ｐ０．５／２０ｋ≤１９Ｗ／ｋｇ,Ｐ０．５／５０ｋ≤９０Ｗ／ｋｇ。以μ（ｋ）ｔ Ｐ０．５／２０ｋ为参数,研究了合金的温度稳定性。研究表明,与２５℃时全金性能相比,在－５０℃和＋５０℃时合金性能的相对变化率不超过５％。介绍了合金在中、高频功率变压器、传感器、电感器等电力电子技     

MB26合金超塑性的研究

研究了新型高强度镁合金ＭＢ２６超塑性拉伸、压缩的变形行为。结果表明，热挤压态ＭＢ２６合金不经过任何预处理即具有很好的超塑性。超塑性拉抻时，在４００℃、ε０＝１．１７×１０＾－２ｓ＾－１的变形条件下δ＝１４５０％，σ＝８．７ＭＰａ，ｍ值为０．６；超塑性压缩时，在４００℃、ε０＝８．３×１０＾３ｓ＾－１变形条件下，压缩真应变ε高达２．１８以上，σ＝１８ＭＰａ，ｍ值在０．４以上。     

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