掺硼金刚石膜的热敏特性

用微波ＰＣＶＤ法将掺硼金刚石膜淀积在Ｓｉ３Ｎ４基片上，用Ｔｉ薄膜作为欧姆接触电极蒸发在金刚石表面上，为防止Ｔｉ在高温下氧化，上面镀上了Ａｕ薄膜，从室温到６００℃范围内测试了这些金刚石膜样的电阻（Ｒ），发现Ｔ＾－１和Ｒ之间呈线性关系，若改变掺硼浓度以及热处理条件可以控制掺硼金刚石膜的热敏特性，结果表明掺硼金刚石膜显示了高的敏感性和好的稳定性，是一咱优良的热敏电阻材料。     

掺硼金刚石薄膜的电化学性能

利用循环伏安法,通过对比掺硼金刚石薄膜电极和铂／金刚石电极分别作为工作电极时的循环伏安曲线,分析了两种电极表现出的电化学性能差别,并利用能级理论进行了机理探讨。结果表明掺硼金刚石薄膜电极具有宽的电化学窗口（宽度约为3V）、良好的化学稳定性和极低的背景电流（接近0）,是一种较有潜力的电化学电极材料。     

金刚石膜电极的电化学研究

概述了电化学水处理方法、高硼掺杂金刚石膜电极的电化学研究.介绍了高硼掺杂金刚石膜电极的制备、金刚石膜电极在无机和有机废水处理方面的应用.实验表明金刚石膜电极对有代表性的污水具有明显的降解作用,可与其它处理方式结合.     

硼掺杂金刚石薄膜电极在酸碱盐中的电化学性质研究

通过热丝化学气相沉积技术,在P型单晶衬底上制备了掺硼金刚石薄膜电极。采用扫描电子显微镜和X射线衍射分析了丙酮流量对硼掺杂金刚石薄膜电极的表面形貌的影响,采用循环伏安法分析硼掺杂金刚石薄膜电极在不同浓度的酸碱盐电解液中的电化学特性。结果表明,硼掺杂金刚石薄膜质量随着丙酮流量的增加而先提高后下降的趋势,并且硼掺杂金刚石薄膜电极在不同电解质中存在不同的电化学窗口,中性溶液中的电化学窗口最宽在3.2 V以上,具有极强的电化学氧化性能。     

掺硼金刚石/硬质合金膜基结合和摩擦磨损性能的研究

金刚石刀具涂层在碳纤维复合材料等难加工材料高效加工方面有着广阔的应用前景。在热丝化学气相沉积系统通过气体掺硼,在硬质合金表面制备了掺硼金刚石涂层。通过SEM、Raman以及压痕测试对涂层的表面形貌、成分和膜基结合性能进行了测试和分析;对涂层进行了摩擦磨损实验,研究了涂层不同环境温度下的摩擦系数及磨损率。结果表明,适量的硼掺杂可以细化金刚石晶粒,提高膜基结合力,降低摩擦系数并提高耐磨性,掺硼金刚石磨损率随温度的升高而增大,本文合适的掺硼浓度为3×10-3。     

掺硼金刚石膜的制备及其应用

金刚石虽然具有极为优异的性能,如具有很大的能隙,高的电子迁移率、空穴迁移率和高热导率,以及负的电子亲和势,但要将它用于半导体材料时还不能直接使用,必须要先进行金刚石的P型和n型掺杂。因此,研究金刚石的P型和n型掺杂具有很重要的现实意义。在金刚石薄膜中掺杂时,一般是掺入硼原子以实现P型掺杂,掺入氮原子或磷原子以实现n型掺杂。然而,由于N和P在金刚石中的施主能级太深,现在n型掺杂金刚石薄膜制备尚不成功,这是金刚石实用化的障碍。本文介绍了金刚石膜掺硼目的、方法和制备,总结了掺硼金刚石膜在微电子、电化学、光电子、工具等领域应用状况以及存在问题。     

Ⅱb型宝石级金刚石的表征及半导体特性研究

利用温度梯度法在高温高压国产六面顶压机上成功合成出尺寸达4mm的优质Ⅱb型宝石级金刚石。利用显微红外吸收光谱对所合成的黄色、无色及蓝色宝石级金刚石的氮、硼杂质进行了测试。通过对比分析认为所合成的除氮、掺硼蓝色宝石级金刚石为Ⅱb型。利用四探针法和霍尔效应法对不同掺硼量所合成的Ⅱb型宝石级金刚石半导体性质进行了测试;总结了掺硼量与金刚石半导体性质之间的变化关系;分析认为硼的添加对Ⅱb型宝石级金刚石的半导体特性的变化起到了决定性作用。     

直流热阴极CVD法中硼酸三甲酯流量对掺硼金刚石膜制备的影响

采用直流热阴极CVD方法,以液态硼酸三甲酯为硼源,在P型(100)硅基片上制备了掺硼金刚石(BDD)膜.利用扫描电子显微镜(SEM)、激光拉曼光谱仪、X射线衍射仪(XRD)等方法对样品进行了表征,研究了其生长特性,并利用电榆运特性测试系统对其电阻率进行了测试.结果表明,随着硼酸三甲酯流量的增加,晶体的表面逐渐光滑平整、棱角清晰;掺硼金刚石膜的品质呈先上升后下降的趋势;电阻率呈先下降后达到平稳的趋势,最终达到约8.0×10-3Ω·cm.硼掺杂明显改变了金刚石晶体的组成结构.     

新型掺氮金刚石薄膜结构及CO2电化学还原性能研究

掺氮金刚石薄膜不仅同已被广泛研究的掺硼金刚石(BDD)薄膜一样拥有优异的电化学性能,而且具有更加丰富的的结构和物相组成,是一种十分有潜力的CO_2电化学还原电极材料。本文采用微波等离子体化学沉积技术通过改变沉积温度(750和850℃)制备获得两种形态结构及组成特点显著不同的新型掺氮金刚石薄膜,SEM、XRD分析表明750℃下生长的薄膜仅含金刚石相且晶粒尺寸在30 nm以下,晶界占比极大,结合Raman光谱图中宽化的D峰和G峰,表明所得膜材为典型的掺氮超纳米金刚石膜(UNCD);而850℃制备的薄膜由金刚石和石墨相组成,极薄的石墨片垂直交叉排列呈"蜂窝"状,尺寸极小金刚石晶粒分布于蜂孔内,为典型的掺氮超纳米金刚石/多层石墨烯复合薄膜(UNCD/MLG)。电化学测试结果显示,两种新型掺氮金刚石薄膜均具有宽的电势窗(～3 V),可以有效地抑制CO_2还原的析氢竞争反应;同时两种电极都可以有效电催化还原CO_2,生成甲酸和CO,甲酸和CO最大法拉第效率分别为38.37%和15.32%。其中850℃生长的UNCD/MLG薄膜具有更好的电化学活性,更高的CO法拉第效率并可产生多电子转移产物甲烷。这得益于其本身"蜂巢"状结构不仅使表面积极大地增加,同时适中的sp~3-C/sp~2-C比例可以有效结合CO_2还原的中间体,增加了产物的多样性。对于掺氮金刚石薄膜材料而言,这种由掺氮超纳米金刚石和多层石墨烯组成的具有丰富孔洞结构的复合膜是一种更有潜力的电催化CO_2还原电极材料。     

气压和偏流对高掺硼金刚石晶体性质的影响(英文)

采用热丝化学气相沉积法,改变工作气压和偏流,在硅基片上沉积了高掺硼金刚石膜。利用扫描电镜(SEM)、拉曼光谱和X射线衍射仪对沉积的金刚石膜表面形貌和结构进行表征。结果显示:当气体压强从3kPa降低到1.5kPa时,金刚石膜有较平的表面形貌和和较好的晶形,薄膜的晶体性质得到良好的改善。但是继续降气体压强,从1.5kPa到0.5kPa时,却呈现出相反的趋势。固定气体压强(1.5kPa),改变偏流,结果表明:适当的偏流(3A)可以改善掺硼金刚石的质量,偏流较高会导致薄膜中非金刚石相增多。     

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 ...     

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.