多能碳离子注入纯铁研究

利用离子注入表面优化技术,在不同温度下,采用多能量叠加方式将碳离子注入纯铁表面;利用XRD和AES等技术分析了表面改性层的相结构以及元素的分布;利用电化学极化法测试了注入样品的抗腐蚀性能.结果表明,573 K时注入的碳离子比373 K时注入的碳离子深;纯铁表面改性层有Fe2C、Fe3C新相生成;离子注入碳提高了纯铁表面抗电化学腐蚀的能力.     

离子束辅助沉积氧化钛对改善热解碳抗凝血性能作用的初步研究

用离子束辅助沉积的方法在人工心脏瓣膜热解碳材料表面制备氧化钛薄膜，研究其对抗凝血性能的改善情况，以探索新型的人工瓣膜材料．对样本分别进行体外血小板黏附试验和动物体内试验以观察血栓形成的情况．结果表明，相比较传统的热解碳材料而言，氧化钛薄膜处理过的材料上黏附的血小板数目和聚集的血小板团数均明显减少，且血小板伪足数目亦明显减少．动物体内试验亦表明有氧化钛薄膜的样本表面形成的血栓较传统的热解碳材料要少，且没有热解碳材料表面有大量的血小板聚集和纤维蛋白形成．研究结果显示用离子束辅助沉积技术制备的氧化钛薄膜，其抗凝血性能优于目前临床应用的热解碳材料，很可能成为新一代的人工瓣膜材料。     

P掺杂类金刚石薄膜的制备及生物学行为研究

应用等离子体浸没离子注入与沉积方法合成了磷掺杂的类金刚石(diamond like carbon,DLC)薄膜.结构分析表明磷以微米级岛状结构分散于DLC薄膜表层,P的掺杂增加了DLC薄膜的无序性,俄歇能谱表明岛型区域是由P、C、O三种元素形成的化合物.掺杂表面表现出强烈的亲水性(水接触角为16.9°),体外血小板粘附实验结果显示,P掺杂DLC薄膜表面粘附的血小板少且变形小,表现出的血液相容性优于热解碳和未改性DLC.     

退火温度对P离子注入TiO2薄膜材料物理与生物学性能的影响

利用离子注入技术在TiO2薄膜中注入P元素,然后分别在不同温度进行退火处理,得到一系列钛氧化物掺杂材料.随着退火温度的上升,P注入的TiO2薄膜材料电阻降低,与水的接触角在70度左右波动.通过LDH及血小板粘附实验,发现高温退火样品的血液相容性得到改善.     

单壁碳纳米管无纺膜的抗凝血性能研究及其对血液系统中植入性假体的意义

以血液接触环境下的应用为目标，研究了单壁碳纳米管无纺膜的抗凝血性能。通过扫描电镜(SEM)观察和表面元素分析，研究了与凝血过程密切相关的纤维蛋白原、白蛋白以及新鲜血浆在单壁碳纳米管无纺膜表面的吸附行为，并利用SEM和荧光标记流式细胞分析技术(FCM)，从血小板活化形态和血小板膜糖蛋白的构型变化两个方面分析了单壁碳纳米管无纺膜对血小板的作用。实验结果显示，单壁碳纳米管无纺膜对血液中的纤维蛋白分子原具有明显的倾向性吸附，但是并没有像已有的大部分生物材料一样引起明显的后续血小板粘附和活化，材料与血浆接触后，表面上没有观察到可辨识的血小板粘附与活化，富血小板血浆(PRP)中活化血小板在5％左右，表明该材料具有独特的抑制血小板粘附、活化和聚集的抗凝血性能。这种优异的抗凝血性能在血液接触环境中的人工器官、组织替代物、以及可植入器件等方面具有巨大的潜在应用价值。     

PLGA携载紫杉醇涂层包被TiNi合金的表面特性与生物性能

系统研究了PLGA携载紫杉醇包被TiNi合金的表面特性与生物性能。采用原子力显微镜(AFM)和X射线光电子能谱(XPS)研究了药物涂层的表面形貌及化学成分;采用高效液相色谱(HPLC)研究了在pH为7.4的PBS溶液中紫杉醇从TiNi合金表面涂层中释放特性,并通过血小板粘附试验研究了药物涂层的血液相容性。试验结果表明经涂覆后TiNi合金表面化学组成及结构随着载药量的增加而改变。紫杉醇在涂层降解初期释放较快,随着时间的延长,累积释放量增加缓慢。血小板粘附试验表明载药量为0%、10%、20%和30%时涂膜样品表面血小板粘附数量均小于未涂膜样品表面。而随着载药量的增加,涂膜样品表面粘附的血小板数量增加,血小板变形严重,当载药量为30%时,血小板出现明显的聚集现象。     

用离子注入改善铍表面性能

本文研究了离子注入对铍表面硬度及磨损性能的影响,用x射线分析了注入后的表面结构。结果表明,离子注入对铍表面的磨损性能有很大改善,硬度得到提高,耐磨层深度是注入离子射程的10倍。并讨论了离子注入改善表面磨损性能及硬度提高的机理。     

银离子注入ABS树脂抗菌性能研究

用MEVVA源将银离子注入ABS(Acrylonitrile Butadiene Styrene)树脂表面,研究在注入剂量为1.0×1016ions/cm2、注入能量由5 keV到30 keV材料的抗菌性。通过X射线光电子能谱(XPS)及拉曼(Raman)光谱对样品表面进行了表征,并测试样品的疏水性和抗菌性。结果表明:载能离子导致ABS树脂表面部分化学键断裂,并出现失氢、富碳,而银以离子形式存在其氧化物中;材料表面的接触角变大,由亲水性材料变为疏水性材料;银离子注入后材料具有良好的抗菌性能,抗菌效果随着离子注入能量的增加呈现降低趋势。     

纯铜表面纳米化对Ti离子注入的影响

为了改善金属材料表面的综合性能,将表面改性技术和纳米技术相结合逐渐得到了人们的重视.用金属蒸气孤(MEVVA)源离子注入机,将能量为40keV,剂量为2×1017iONS/cm2的Ti离子注入纳米纯铜中.利用透射电子显微镜(TEM)、X射线衍射仪(XRD)、俄歇电子能谱(AES)对表层组织及注入浓度分布等进行了分析.研究结果表明,纯铜表面经过SMAT纳米化处理后,注入元素的浓度呈现高斯分布,与未处理的样品相比,峰值浓度提高了30%,注入深度达到160nm.     

生物质热解条件对生物焦吸附性能的影响

研究了热解终温、生物质粒径和升温速率对热解所得生物焦吸附亚甲基蓝性能的影响,并结合扫描电镜(SEM)图进行了详细分析。实验表明,热解终温为800℃时得到的生物焦吸附性能较好,孔隙材料和生物焦表面的结构烧蚀较少;生物质粒径为30～60目时热解所得生物焦表面存在的坍塌区较60～100目的少;热解时升温速率的提高使得可燃气产率增加,20℃/min时所得的生物焦吸附性能较好。     

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.