RADA16-I纳米短肽水凝胶力学强度的调控

研究了RADA16-I纳米短肽的二级结构和微观形态及其在不同溶液触发下形成的水凝胶的力学强度.试验结果表明,该短肽在水溶液中形成典型的β-sheet结构,这对其形成纳米纤维十分重要.此外,研究发现采用不同的溶液触发得到的水凝胶的力学强度可在一定范围内变化,符合DLVO理论.这可为组织工程提供强度可调控的纳米纤维支架材料.     

自组装短肽系统及其材料学应用

模仿天然蛋白质的氨基酸序列设计自组装短肽作为纳米材料近年来引起了人们极大的兴趣。本文介绍了几个发展较为成熟的自组装短肽材料以及它们在纳米医学和纳米生物技术等领域的应用,阐述了自组装短肽作为新型纳米材料的巨大潜力。     

树枝状与球状PbS纳米结构的组装合成及其形成机理研究

以醋酸铅为铅源,硫代乙酰胺为硫源,在表面活性剂SDS单独作用和表面活性剂SDS和CTAB共同作用下可选择性地组装合成出颗粒以相同晶面粘连组装成的单晶树枝状PbS纳米结构和颗粒以不相同晶面粘连组装成的多晶球状PbS纳米结构,而且提高反应物浓度能起到调节树枝状和球状PbS纳米结构尺寸的作用.对树枝状和球状PbS纳米结构的形成机理进行了初探,发现SDS单独作用时其烷基链起到的软模板作用有利于PbS小颗粒组装成树枝状的PbS纳米结构.当反应溶液中再加入适量的CTAB时,它在溶液中形成微胶束起到了软模板作用,迫使颗粒粘连组装成球状PbS纳米结构,有效地限制树枝状结构的生长.     

手性超分子凝胶材料的研究进展

超分子凝胶作为一类新型的智能自组装软材料,从分子水平到微纳米水平的组装过程中,手性发挥了重要的作用.一般情况下,手性信号都是直接从分子转换到纳米纤维中,但也有一些有趣的现象,即混合两种对映体可以调控得到不同手性形态的纤维结构,甚至一些本身不具备手性的构筑块同样可以通过外界诱导得到具有手性结构的组装体.对纤维手性自组装机理的研究不仅揭示了分子手性到纤维微纳米手性转换这一重要过程,而且对新型的手性材料和微纳米器件的开发也有启发作用.有关微纳米水平的手性材料在手性识别、不对称催化、生物大分子结晶和无机材料的手性模板剂、生物医用等领域的应用研究也逐渐得到重视.主要综述了近二十年来有关手性超分子凝胶的研究,主要从凝胶因子的手性自组装、手性在分子水平和微纳米水平上的形貌调控和表征方法、超分子凝胶的手性应用几个方面进行概述,并对手性超分子凝胶的应用和研究前景进行了展望.     

碳纳米管/导电聚苯胺纳米复合纤维的合成与表征

为实现碳纳米管在树脂内形成一体化导电网络，从而制备出透明导电性能最优的有机透明导电涂层，必须把导电性的碳纳米管纤维在树脂内有效地组装成一体化导电结构网络。本文报道运用在树脂内可以自组装的导电苯胺来实现碳纳米管纤维自组装的方法．合成出了导电聚苯胺纳米薄膜均匀包覆的碳纳米管/导电聚苯胺纳米复合纤维．并运用透射电镜、傅立叶红外光谱以及四探针法表面电阻测试仪对合成出的具有精细微观结构的纳米复合纤维进行了表征．发现合成出了理想的碳纳米管/导电聚苯胺纳米复合纤维，并且其导电性较碳纳米管和导电聚苯胺自身都有大幅度的提高。这种特殊结构的纳米复合纤维的制备为组装高性能的聚合物基透明导电涂层奠定了坚实基础，而且这种自组装方法为各种纳米纤维的组装提供了可能。     

中国研究亮点：新纳米生物材料

来自四川大学华西医院纳米生物医学技术与膜生物学研究所的研究人员首次设计一种“智能化”的半程电荷匹配短肽，通过调节浓度和施加超声等外部作用，能人为地控制短肽形成“渔网式”或“席状”的纳米生物材料。这一研究成果公布在《美国国家科学院院刊}（PNAS）杂志上。以往自组装纳米生物材料的形成多是自发形成，很难人为控制纳米材料的形成过程和材料特性。     

花状ZnO超细结构的水热自组装

通过简单的水热合成路线,合成出由ZnO纳米棒束组装的花状结构.其组成结构单元ZnO纳米棒沿［001］晶向生长,呈很好的单晶结构.大部分纳米棒直径约为500nm,长约6.0μm.研究结果表明,在无水乙二胺存在的条件下,氨水（28%, v/v）在ZnO花状结构的形成过程中起到了至关重要的作用.调节氨水的含量,组成结构单元ZnO纳米棒可以组装成不同的花状结构.当加入氨水的量使得溶液的pH值达到10时,即可得到由ZnO纳米棒束组装成的花状结构,并简单讨论了这种花状结构的形状结构的形成机理.      

SF/PEI自组装纳米纤维膜用于Cu2+过滤的研究

采用静电层层自组装技术将丝素(SF)与聚乙烯亚胺(PEI)复合制备的SF/PEI纳米纤维,随着自组装层数的增多,纤维直径变粗,表面变得不规整,且在一定的自组装层数内,复合纳米纤维膜对Cu2+的过滤效率不断增大.杂化Fe后,纤维表面变得更加凹凸不平,但对Cu2+的过滤效果显著改善.这对于制备新型、高效、无二次污染、低治理成本的替代或改进的重金属过滤材料提供了理论意义.     

小分子硼酸肽的自组装

利用FMOC化学固相多肽合成法合成了3种含精氨酸的小分子硼酸肽(标记为BPs(1-3))。在生理pH下,含阳离子的硼酸肽可自组装形成有序超分子纳米组装体。二羟基酚染料茜素红与硼酸肽可特异性结合形成五元环硼酸酯,伴随荧光和颜色的显著变化,可进一步调控硼酸肽的自组装行为。通过扫描电镜研究茜素红调控前后硼酸肽的自组装形态,并用红外光谱和圆二色谱研究其自组装机理。结果表明,3种含精氨酸硼酸肽在生理pH下可自组装形成不同的超分子纳米组装体。通过茜素红的调控,茜素红/硼酸肽化合物,可自组装形成更有序,更精致的超分子聚集体。     

基于β-聚苹果酸衍生物的两种聚合物胶束的制备

合成聚苹果酸苄基酯（PMLABz）和聚苹果酸（PMLA）,在此基础上构建两种不同类型的聚合物胶柬,通过合成PMLABz、PMLA、聚乙二醇-聚苹果酸-喜树碱-I（P1）和聚乙二醇-聚苹果酸-喜树碱-II（P2）,利用动态透析法制备P1、P2胶柬,并进行表征、筛选。为了进一步增强胶束细胞的内摄作用和特定肿瘤细胞的靶向性,用靶向分子叶酸修饰胶柬,结果显示,该方法能成功制备药物载体PMLABz、PMLA及共聚物P1、P2,其中,P1是接枝共聚物,能够自组装成平均直径100nm星型胶束（载药量：11．2％,粒径：97.2±4．6nm,zeta电位：-18．5mV）;P2是嵌段共聚物,能够自组装成平均直径75nm的平头型胶束（载药量：20．5％,粒径：76．4±3．8nm,zeta电位：-16．4mv）;P1、P2胶柬形态圆整,粒径均匀,因此,P1、P2胶柬是一种潜在的自组装给药体系。     

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.     

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.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to