PS/SiO2纳米杂化材料的制备及作为菜籽油添加剂的摩擦学性能

用无皂乳液聚合法一步制备了聚苯乙烯/表面有机化二氧化硅（PS/SiO2）纳米杂化材料，采用红外光谱（FF-IR）、透射电子显微镜（TEM）以及热分析（TGA-DSC）等对材料的核-壳结构进行了表征，表明PS/SiO2纳米杂化材料为平均粒径在60nm左右的良好分散圆球。利用四球机考察了添加剂在菜籽油中的摩擦学性能。结果表明，合成的PS/SiO2纳米杂化材料能提高菜籽油的抗磨性能及承载能力，并能降低摩擦系数，其最佳用量为1.0％。     

PES／纳米SiO2杂化膜的成膜机理及性能研究

利用湿法相转化方法，通过在聚醚砜（PES）铸膜液中添加适量的纳米粒径的SiO2，制得了具有不同含量纳米SiO2的PES／SiO2杂化膜。对分相过程中的成膜动力学、膜的微观结构以及性能进行了分析测试，结果表明与纯PES相比，铸膜液中添加了4wt％纳米SiO2后，PES体系的成膜速度有所提高。膜断面的SEM照片表明，PES／SiO2杂化膜有更大的指状孔。膜性能测试结果表明，体系中SiO2含量对PES杂化膜的纯水通量和截留率有影响，在添加的纳米SiO2的含量较少时，所得PES杂化膜的截留率明显升高，水通量则相反而有所降低；随着体系中SiO2含量的进一步增加，PES／SiO2杂化膜的水通量明显增大，同时增强的截留率也得到了保持。     

PPESK／SiO2杂化材料的制备及动态力学性能研究

以含二氮杂萘酮结构聚芳醚砜酮（PPESK）为基体，正硅酸乙酯（TEOS）为原料，N-甲基吡咯烷酮（NMP）为共溶剂，采用溶胶-凝胶方法制备出不同二氧化硅质量百分含量的PPESK／SiO2杂化材料。利用动态热机械分析仪（DMA）对PPESK／SiO2杂化均质薄膜进行动态力学性能测试和表征。结果表明，杂化材料中SiO2组分含量及扫描频率对PPESK／SiO2杂化材料的动态力学性能及玻璃化转变过程都有一定程度影响。SiO2含量的增加，杂化材料的力学损耗峰温度移向高温区，并且峰值升高；随着扫描频率的增加，杂化材料的损耗因子峰移向高温。同时采用Arrhenius方程计算PPESK／SiO2杂化材料在α转变时分子运动活化能。另外，还考察了SiO2粒子含量对PPESK／SiO2杂化材料的力学性能的影响。     

聚醋酸乙烯酯／二氧化硅杂化纳米纤维膜的制备与性能

采用溶胶一凝胶法将二氧化硅（SiO2）溶胶加入到聚醋酸乙烯酯（PVAc）的丙酮溶液中形成杂化纺丝液，测试了纺丝液的表面张力、粘度、电导率，再采用高压静电纺丝法制备了PVAC／SiO2杂化纳米纤维膜。结果表明，SiO2的加入改善了纳米纤维膜的形貌特征，膜的断裂强力增大，但断裂伸长率却有所降低，而膜的热稳定性也得到了提高。     

纳米纯丙胶乳制备TiO2-SiO2杂化材料的研究

用溶胶-凝胶法制得的纳米TiO2-SiO2溶胶，与纳米级的纯丙微胶乳直接共混，制备了聚丙烯酸酯／TiO2—SiO2纳米复合胶乳。用红外光谱（FT—IR）、热重分析仪（TGA）和紫外-可见光谱仪（UV—Vis）分别表征了纳米复合胶膜的化学结构及形态、热学和光学性能。实验证实，该纳米杂化材料具有优异的紫外线屏蔽作用和热稳定性。     

MSU-J及有机化修饰对PMMA杂化材料力学性能和热性能的影响

采用蠕虫状介孔SiO2(MSU-J)和γ-(甲基丙烯酰氧)丙基三甲氧基硅烷后嫁接法有机化修饰的MSU-J-G,与MMA原位聚合制备具有三维纳米网络结构的MSU-J/PMMA和MSU-J-G/PMMA杂化材料。研究了杂化材料的微观结构、力学性能和热性能。结果表明:杂化材料中MSU-J及MSU-J-G保持原有的蠕虫状介孔结构,且近90%孔道被PMMA填充。MSU-J或MSU-J-G质量分数为7%时,两类杂化材料的性能最优,相对于纯PMMA,其拉伸强度和模量分别提高了38.9%和40.2%(MSU-J)以及46.7%和39.5%(MSU-J-G),断裂伸长率及冲击强度略有下降。杂化材料的热分解温度(Td)及玻璃化转变温度(Tg)也得到了改善。相对于MSU-J,MSU-J-G在PMMA中分散更均匀,对于杂化材料的力学和热性能改善效果更佳。     

PMMA／SiO2杂化纤维的制备及表征

以正硅酸乙酯(TEOS)和PMMA低聚体为原料,乙烯基三乙氧基硅烷(VTEOS)为偶联剂,采用溶胶-凝胶法制备了PMMA/SiO2杂化溶胶,陈化后用提拉法制得PMMA/SiO2杂化纤维。研究了溶胶的杂化反应机理、成纤性能;使用IR、SEM、TGA及DSC分析了杂化纤维的结构与性能。结果表明,该杂化溶胶具有很好的拉丝性能,黏度为180 Pa.s~300 Pa.s时的成纤性能好,所制得的杂化纤维,其中PMMA与SiO2之间通过化学键连接,在纤维内部有机无机相间形成均一的连续相;其耐热性能优于纯PMMA。     

纳米SiO_2的表面改性及作为润滑油添加剂的研究进展

纳米SiO2用作润滑油添加剂的研究尚处于起步阶段,但从研究结果看出,它具有优良的摩擦学性能。本文中简单介绍了纳米SiO2表面改性方法,总结了它作为润滑油添加剂的研究现状;并对作用机理进行了探讨;最后提出其作为润滑油添加剂的发展趋势,即纳米SiO2粒子的制备和表面修饰的“一体化”,制备高聚物-纳米SiO2杂化粒子以及对其摩擦学机理进行研究。     

低介电常数的介孔SiO2/PMMA杂化材料的研究

为降低PMMA的介电常数,同时提高其力学性能和热性能,利用原位分散聚合法以二维六方孔结构SiO2(SBA-15)和蠕虫状孔结构SiO2(MSU-J)为填料制备了PMMA杂化材料.采用XRD、FT-IR、SEM、TEM和DSC等方法研究了杂化材料的微观形貌特征、介电常数、力学性能和热性能.结果表明:含质量分数7%有机化修饰的SBA-15或MSU-J的PMMA杂化材料介电常数由2.91分别降至2.68和2.56;且在较宽范围频率下杂化材料的介电常数稳定.这主要是由于介孔孔道储存空气(κ=1)、界面间隙及大的粒径带来的自由体积的引入降低了杂化材料的介电常数,同时也使杂化材料的力学性能和热性能得到显著提高.     

改性甲基丙烯酸酯/SiO2-TiO2纳米复合材料的制备与表征

用原住复舍、溶胶-凝胶法制备了有机聚合物链段与无机相间有共价键存在的改性甲基丙烯酸酯类共聚物／SiO2-TiO2杂化纳米复合材料。通过红外光谱，透射电镜，扫描电镜对材料的结构和形态进行了表征，并对纳米分散相的形态、分布和界面状况对杂化材料的物理化学性能及氧阻透性能进行了测试．对结构与性能的关系进行了探讨．     

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.