氯丁橡胶／蛭石纳米复合材料的研究

以蛭石和氯丁橡胶为原料，采用溶液插层法将氯丁橡胶插入蛭石层间，制备聚合物层状硅酸盐纳米复合材料，用X射线衍射仪对样品进行分析测试，结果表明，得到了剥离型氯丁橡胶／蛭石纳米复合材料。     

碳/蒙脱石复合材料的制备和表征

以蔗糖、蒙脱石为原料,在超声分散条件下,采用溶液插层、碳化方法制备插层型碳/蒙脱石纳米复合材料,通过X射线衍射(XRD)和红外光谱(FTIR)等分析表征方法对插层型蔗糖/蒙脱石纳米复合材料、碳/蒙脱石纳米复合材料进行表征,XRD结果表明,在400W的超声及70℃下,按蒙脱石:蔗糖:蒸馏水=1:2:20的比例超声反应2h,静置2h后能够得到d001=1.80nm的蔗糖/蒙脱石复合材料;将其在400℃氮气氛中碳化3h能够得到d001=1.34nm的复合材料。FTIR谱图表明,蔗糖/蒙脱石复合材料碳化完全,最终获得了具有三明治结构的碳/蒙脱石纳米复合材料。     

非剥离型聚苯胺/蒙脱土碳纳米复合吸附材料的研究

采用原位插层聚合法制备非剥离型聚苯胺/蒙脱土纳米复合吸附材料,研究了过氧化环己酮、异辛酸钴的用量和反应时间,以及碳化温度对复合材料性能的影响。结果表明:引发剂的用量为3%,促进剂的用量为5%,聚合反应时间为1.5h,所得的聚苯胺/蒙脱土复合材料的层间距最大,达21.54;碳化温度为500℃,所得的碳纳米复合材料的比表面积最大,达52.39m2/g。利用XRD、FT-IR、TG和BET等手段对该条件下制备的纳米复合材料进行了表征。     

超声波对硅树脂/蒙脱土纳米复合材料热性能的影响

采用超声波技术,原位插层聚合法制备了甲基苯基硅树脂/有机蒙脱土(OMMT)纳米复合材料。X射线衍射(XRD),透射电镜(TEM)研究了复合材料内部结构以及超声波时间对蒙脱土分散性和复合材料热性能的影响。简单控制超声波时间15和30min,分别制备了不同OMMT质量分数的插层型和剥离型聚合物/蒙脱土纳米复合材料。加入OMMT,无论是插层型还是剥离型,复合材料的起始分解温度都有所下降,但热失重速率较平缓。插层型纳米复合材料耐热性能明显优于剥离型,温度500℃时,插层型热失重均小于纯硅树脂。当OMMT含量8%时,插层型PLS复合材料500℃的热失重均10%;而剥离型PLS复合材料500℃的热失重较大,超过15%。     

环氧树脂/粘土纳米复合材料的制备与性能研究

研究了有机蒙脱土在环氧树脂中的插层和剥离行为,制备了两种环氧树脂/蒙脱土纳米复合材料并测试了其力学性能。实验结果表明,环氧树脂与有机土的相容性好,二者混合时环氧树脂很容易插入到粘土层间。使用经不同有机阳离子处理的两种有机蒙脱土,分别制得插层型和剥离型环氧/粘土纳米复合材料,力学性能结果表明,剥离型纳米复合材料的性能优于同组成的插层型纳米复合材料。     

聚合物/粘土纳米复合材料的插层制备方法

介绍了插层制备聚合物/粘土纳米复合材料的主要方法:剥离-吸附法、原位聚合插层法、熔融插层法和模板合成法;对插层法制备聚合物今后的研究方向提出一些建议.     

原位乳液插层法制备PBA/OMMT纳米复合母料及其在ABS中的应用

通过原位乳液插层法制备高有机蒙脱土(OMMT)含量的聚丙烯酸丁酯/有机蒙脱土(PBA/0MMT)纳米复合物,将其作为母料与ABS进一步熔融插层制得力学性能良好的ABS/OMMT纳米复合材料,并通过XRD、TGA和TEM等对材料进行了表征.结果表明:制得的PBA/OMMT母料为插层型纳米复合物,OMMT片层间距从2.38nm增大到3.85nm;采用母料法制备ABS/OMMT纳米复合材料,ABS链段易插层进入OMMT层间,使OMMT片层在ABS基体中达到剥离并以纳米尺度均匀分散,较好地保持了ABS的缺口冲击强度.     

胺类固化剂-插层剂体系对粘土在环氧树脂中剥离的影响

在对胺类固化剂-插层剂体系分析的基础上,选定叔胺类固化剂(BDMA)-Bronsted酸类插层剂(CH3(CH2)11NH3Cl)体系,制得了环氧树脂/粘土纳米复合材料,复合材料的XRD分析表明粘土在环氧树脂中已经剥离.结合有关研究成果,得出以下结论:在其他条件合适的情况下,只要插层剂为Bronsted酸类或者固化剂为叔胺类,就能得到剥离型的环氧树脂/粘土纳米复合材料.     

添加剂对聚吡咯/氧化石墨纳米复合材料结构和性能的影响

采用单体原位聚合法制备了三种聚吡咯/氧化石墨纳米复合材料。通过XRD、FT-IR和TEM对产物进行结构表征,探讨了未加添加剂及分别以N aOH和十二烷基苯磺酸钠为添加剂制得的聚吡咯/氧化石墨纳米复合材料的结构与性能的差别。结果表明,未加添加剂和以N aOH为添加剂时产物为非晶态的剥离型聚吡咯/氧化石墨纳米复合材料;而以十二烷基苯磺酸钠为添加剂时可得到具有层状有序结构的插层型聚吡咯/氧化石墨纳米复合材料。插层型聚吡咯/氧化石墨纳米复合材料的导电和电化学性能优于剥离型聚吡咯/氧化石墨纳米复合材料,它们的提高归因于聚吡咯分子链共轭程度的增加。     

聚乳酸/蒙脱石纳米复合材料的制备与表征

对纳基蒙脱石(MMT)有机改性后,采用溶液插层薄膜塑造工艺制备蒙脱石/聚乳酸(PLA)纳米复合物,采用X-Ray粉晶衍射(XRD)、综合热分析(TGA&DSC)、红外吸收光谱(IR)等方法对复合材料进行表征,讨论了蒙脱石对插层结果的影响.结果表明,PLA能够插入MMT层间;MMT的层间距由1.40nm增大到2.16nm;复合材料的热稳定性能得到改善.     

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.