阳离子表面活性剂为乳化剂原位乳液聚合制备PS/MMT纳米复合材料

针对原位乳液聚合法制备聚合物/蒙脱土(MM T)纳米复合材料,为了实现蒙脱土片层的有机化处理和纳米复合材料的形成一步完成,以十六烷基三甲基溴化铵为乳化剂原位乳液聚合制备了PS/MM T纳米复合材料。XRD、FT-IR、TEM等分析表明,聚苯乙烯已插层进入蒙脱土的层间。在制备过程中,CTAB既充当了乳化剂,又充当了蒙脱土的插层处理剂,促进了苯乙烯在蒙脱土层间的聚合,同时也造成了蒙脱土片层一定程度的聚并。DSC分析表明,复合物的玻璃化转变温度有一定程度的提高。另外,还对蒙脱土存在下乳液聚合的特点进行了研究,发现MM T片层对乳液聚合的影响仅在聚合反应的初始阶段,使聚合速率有所下降,而对反应的后期阶段和反应产物的分子量影响不大。     

MC尼龙蒙脱土纳米复合材料的制备与表征

在超声条件下以KH550硅烷偶联剂插层蒙脱土,采用阴离子聚合反应制备MC尼龙蒙脱土纳米复合材料(MMT/PA),并对改性蒙脱土和纳米复合材料的结构进行表征与性能测试。结果表明,在超声分散条件下KH-550硅烷偶联剂进入蒙脱土的片层间,增大层间距;聚合过程中己内酰胺进入蒙脱土的片层间,实现蒙脱土与己内酰胺的键性结合,并使得最终尼龙分子插层进入蒙脱土的片层间形成纳米复合材料。蒙脱土以部分剥离的多片层聚集体均匀地分散在尼龙基体中,起到增强增韧作用,当蒙脱土含量在3%左右时纳米复合材料的力学性能达到最优。     

共插层剂改性蒙脱土制备尼龙1010/蒙脱土纳米复合材料

以间甲酚(MC)、尼龙66盐(NS)分别与十六烷基三甲基溴化铵(CTAB)共插层改性蒙脱土，制备了尼龙1010／蒙脱土纳米复合材料。TG和WAXD实验结果表明，采用共插层剂改性的蒙脱土的片层间距显著增大，且热分解温度较高；蒙脱土的引入改善了尼龙1010的拉伸性能、弯曲性能和热变形温度，冲击韧性基本保持；蒙脱土的加入可能改变了尼龙1010的结晶结构，且使尼龙1010的结晶温度升高。共插层剂两组分所起的作用不同，CTAB的插入有利于蒙脱土片层间距的扩开，MC和NS则起到了界面相容剂的作用．有利于基体树脂与蒙脱土片层的复合。     

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.     

聚氨酯/蒙脱土纳米复合弹性体材料--(Ⅱ)结构及性能的表征

借助锥体磨的研磨剪切外力，将聚醚多元醇插层进入蒙脱土片层中，使其片层间距扩大并发生部分剥离，从而利用本体插层聚合法制备了综合性能优异的聚氨酯／蒙脱土纳米复合弹性体材料。当有机蒙脱土添加量仅为1％时，其拉伸强度比纯聚氨酯弹性体高30％．达到30．2MPa，断裂伸长率也略有增加。TGA及吸水实验分析表明聚氨酯／蒙脱土纳米复合材料有更高的热失重温度和更低的吸水率．研究了蒙脱土含量对聚氨酯／蒙脱土纳米复合材料各项性能的影响。     

EVOH/蒙脱土插层型纳米复合材料的研究

将蒙脱土有机化处理,然后将有机化蒙脱土与乙烯-乙烯醇嵌段共聚物(EVOH)通过Brabender流变仪熔融共混,制得纳米复合材料.通过电子透射显微镜、傅里叶变换红外光谱分析,X射线衍射分析等手段对该复合材料进行了结构测试.结果表明:EVOH可以插入有机化蒙脱土片层间;聚乙烯吡咯烷酮改性蒙脱土被EVOH插开的片层距离比季铵盐改性蒙脱土被EVOH插开的片层距离大;有机化蒙脱土在复合材料中比例越小,复合体系中蒙脱土被插开的片层间距越大;当有机化蒙脱土含量为8%时,形成剥离型纳米复合材料;当有机化蒙脱土含量为15%时,形成插层型纳米复合材料.     

PMAA／MMT纳米复合材料的制备

采用原位插层聚合法制备聚甲基丙烯酸/蒙脱土(PMAA/MMT)纳米复合材料,探讨了引发剂用量对复合材料结构的影响。通过X射线衍射、红外光谱、固体核磁共振表征了改性蒙脱土及复合材料的结构。研究结果表明,甲基丙烯酸钠与蒙脱土具有一定的相互作用,甲基丙烯酸或甲基丙烯酸钠在蒙脱土层间聚合形成的PMAA/MMT纳米复合材料属于插层型纳米复合材料,引发剂用量对蒙脱土的层间距影响较小。     

蒙脱土/PE/PVC三元纳米复合材料的制备与结构性能研究

钠基蒙脱土（Na-Mont）预先负载小分子单体丙烯酰胺和引发剂过氧化二异丙苯，发现经处理的蒙脱土（AM-Mont）层间距增大.将负载有丙烯酰胺和过氧化二异丙苯的蒙脱土与PE/PVC在双辊上混合，通过双辊的剪切作用进行插层复合.用FT-IR、XRD等测试方法对复合材料进行表征，表明蒙脱土/PE/PVC三元纳米复合材料是插层型纳米复合材料。     

醋酸纤维素/蒙脱土生物纳米复合材料的结构与力学性能

采用熔融插层法在聚乙二醇的增塑作用下制备了醋酸纤维素/蒙脱土(CA/MMT)生物纳米复合材料。利用X射线衍射和透射电镜表征了CA/MMT纳米复合材料的插层结构。X射线衍射结果表明,复合后蒙脱土的层间距增大;透射电镜照片显示,蒙脱土在CA基体中达到纳米级分散,且分散均匀。CA/MMT纳米复合材料的力学性能得到较大提高,加入5 phr有机蒙脱土时,复合材料的拉伸强度从纯增塑CA的38.8 MPa增到48.2 MPa。动态力学测试表明复合材料的储能模量增大,玻璃化转变温度提高。     

溶液剥离-吸附法制备高分子纳米复合材料

采用溶液剥离-吸附法制备了乙烯基聚合物/改性蒙脱土(VP/C-MM T)高分子纳米复合材料。X射线衍射检测结果表明,十六烷基三甲基溴化铵(CTAB)改性蒙脱土的层间距由1.2916 nm增加到1.9620 nm,与乙烯基聚合物(VP)复合后,蒙脱土的d(001)峰消失;透射电镜对纳米复合材料成膜物的检测结果表明,蒙脱土在VP基体中以片层形式分散,说明VP/C-MM T为剥离型纳米复合材料。示差扫描量热检测结果表明,蒙脱土的存在可以较好地提高聚合物的热稳定性。通过建立CTAB与蒙脱土插层的理论模型,解释了VP与C-MM T未发生相分离的原因。     

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.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

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