材料表面改性脉冲高能量密度等离子体研究

采用热敏纸和量热计作为诊断手段，研究了同轴等离子体枪产生的脉冲高能量密度等离子体的空间分布及其对材料表面改性的影响。结果表明，在一定的轴向距离内，等离子体束呈现轴对称截面分布，其沉积能量密度在（1．3～5）×104J／m2之间。为获得较好的表面改性结果，要求等离子体束的沉积能量密度在（2～2．5）×104J／m2范围内，并在束截面内均匀分布。同轴枪电极结构及放电电压等均对等离子体束的能量密度及其分布具有明显影响，因此可通过改变同轴枪参数，以获得所需的等离子体条件。     

比对法漏率校准装置

比对法漏率校准装置是计量气体漏率的一种装置 ,可绝对法和相对法对真空漏孔进行校准。绝对法的校准范围为 10 - 4～ 10 - 9Pa· m3/s;相对合成标淮不确定度为小于 10 %。相对比对法的校准范围为 10 - 6～10 - 1 0 Pa· m3/s,相对合成标准不确定度为小于 2 5 %。     

镁及镁合金微观侵蚀剂

侵蚀剂名称及成分使　用　方　法适用范围草酸溶液 :草酸水2 m L10 0 m L　擦拭 3～ 5 s,用热水或冷水冲洗　显示铸造镁合金及锻造镁合金硝酸溶液 :A 硝酸水B硝酸乙基乙二醇水0 .5～ 2 .0 m L10 0 m L1m L75 m L10 0 m L　擦拭 3～ 10 s,用热水冲洗　擦试 3～ 10 s,用热水冲洗　用硝酸 5 m L 时显示镁及镁合金 ,用0 .5 m L时可显示变晶组织。 B试剂显示一般组织 ,适用于时效处理后的镁合金 ,显示晶界及组织酒石酸溶液 :酒石酸水2 g10 0 m L　擦拭 10～ 2 0 s 　显示含铝、锌、锰的镁合金柠檬酸溶液 :柠檬酸水5～ 10 m L10 0 m L　擦拭…     

脉冲电沉积CeO2-SiO2／Ni—W-P纳米复合镀层性能研究

为了探讨脉冲参数对CeO2-SiO2/Ni-W-P四元纳米复合镀层性能的影响,采用脉冲沉积的方法,在普通碳钢表面制备了CeO2-SiO2/Ni-W-P纳米复合镀层.在脉冲关断时间1 000μs和脉冲峰值电流密度30 A/dm2下,研究了脉冲导通时间对纳米复合镀层组织及性能的影响,采用能谱分析、硬度测试、扫描电镜(SEM)等技术对镀层化学组成、沉积速率、显微硬度和表面形貌进行了表征.结果表明,纳米复合镀层中CeO2和SiO2颗粒的质量分数随着脉冲导通时间的延长而增加,当脉冲导通时间为400～600μs时,沉积速率为32.33～38.22μm/h,显微硬度为609～674 HV;脉冲导通时间由100μs增加到400μs时,纳米复合镀层晶粒尺寸降低,但当脉冲导通时间再由400μs增加到1000μs时,纳米复合镀层晶粒尺寸又有所增加.     

用于油田抽油泵滑动密封的磁性液体研究

采用直流电弧等离子体法制备了铁、镍、钴及其合金的磁性超微粒子 (UFP) ,平均粒度小于 10 0nm。利用金属或合金超微粒子 ,选择适当的表面活性剂和载液 ,制备了高粘度磁性液体密封材料 (MF) ,常温 (2 5℃ )粘度为 (2 .6～ 3.8)× 10 5mPa·s,高温 (70℃ )粘度为 (1.5～ 2 .2 )× 10 5mPa·s ,室温下饱和磁化强度为FeMF 40 3～ 6 41G/g ,NiMF15 1～ 188G/ g ,Fe-NiFM 44 2～ 6 91G/g。使用高粘度磁性液体密封材料和具有补偿磁流体功能的密封器件 ,实现了对抽油泵的防泄漏密封 ,提高泵效 2 0 %左右 ,延长了泵的运行周期     

碳纳米管薄膜的低温制备及其场发射性能的研究

利用电镀方法在覆盖有金属Ti的玻璃衬底上制备了Ni催化剂,采用微波等离子体化学气相沉积技术,以CH4和H2为反应气体,在450℃的低温下制备了CNTs薄膜.利用扫描电子显微镜和Raman光谱对其表面形貌和结构进行了分析,在真空度小于2×10-4 Pa的环境中测试了CNTs薄膜的场致电子发射特性,开启电场2.7 V/μm.研究表明微波等离子体化学气相沉积技术低温制备CNTs薄膜是可行的,且该薄膜具有良好的场发射性能.     

微波等离子体化学气相沉积的 a-Si∶H 性能研究

本文着重对微波等离子体化学气相沉积法高速沉积的 a-Si∶H 膜的物理性能进行评价研究.测量了沉积膜的光电性能、暗电导激活能、光禁带宽度、光吸收特性、沉积膜中悬键态密度以及氢含量等,并讨论沉积条件对膜性能的影响.结果表明,在沉积速率高达30～90(?)/s 情况下,膜的光电导(光照强度10~5Lux)与暗电导比值可达10~3～10~5,暗电导率从10~(-3)到10~(-11)((?)cm)~(-1),其激活能在0.23～0.88eV 之间(0～200℃温度范围内),光禁带宽度为1.40～2.20eV,氢含量约为2～20%.     

脉冲阴极弧金属等离子体源的调试及其应用

对脉冲阴极弧金属等离子体源的工作参数进行了测量,研究了离子流与磁导管偏压以及磁场电流与离子流之间的关系,确定了其最佳工作参数.并应用该脉冲阴极弧金属等离子体源和等离子体浸没离子注入与沉积技术制备了TiC薄膜.对改性层的显微硬度、摩擦磨损性能和膜基结合力进行了测试分析.结果表明:合成TiC薄膜后,试样的显微硬度、摩擦磨损性能得到了明显的改善,并且膜层与基体之间的临界载荷为36.03 N.     

脉冲放电工艺参数对TiC涂层形成的影响

采用液相脉冲放电技术对机械切削加工工具材料表面进行改性,具有很大的经济效益.将高熔点金属Ti电极置入含碳的液相介质中,利用脉冲放电所产生的低温高能等离子体在45钢基体上沉积TiC陶瓷涂层.讨论了脉冲放电工艺参数对涂层形成与涂层硬度的影响.结果表明:脉冲宽度和峰值电流是影响涂层沉积的主要因素,脉冲间隔和放电沉积时间对涂层厚度有影响,而对涂层的硬度几乎没有影响;在小峰值电流(8 A)和窄脉宽(12 μs)的条件下,可以获得高硬度的TiC涂层.     

高准确度脉冲时间间隔的产生

本文介绍一种数字式高准确度脉冲时间间隔的产生原理和技术特征 ,延迟时间范围 0～ 1s,1s以内时延的不确定度小于1ns。     

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.