一种碳硼烷改性有机硅树脂的制备及其耐热性能

碳硼烷改性有机硅树脂是一种耐热性能优异的高分子材料,具有广阔的应用前景.然而由于聚合单体碳硼烷改性硅氧烷的合成条件苛刻,严重影响碳硼烷改性有机硅树脂的制备和应用.本研究利用羟基与异氰酸酯基间的加成反应,在温和的条件下合成了一种新型结构的碳硼烷改性硅氧烷-碳硼烷改性氨酯桥接丙基三乙氧基硅烷(CBR-Si),在此基础上经水...     

原子转移自由基聚合在生物材料中的应用

生物材料表面改性以及具有特定结构与功能的先进生物材料的合成始终是生物材料研究的核心课题.原子转移自由基聚合( ATRP)是一种新型自由基聚合,在生物材料表面改性以及新型生物材料合成方面具有巨大的应用前景.利用ATRP技术可以提高生物材料表面生物相容性、生物适应性以及生物功能性,如提高材料表面的抗生物污染性、血液相容性、细胞相容性以及抗菌性能等;同时,ATRP也可用于合成新型生物医用高分子材料,如两亲性高分子、纳米胶束、智能水凝胶以及一些具有特殊结构的高分子(包括星型、超支化、梳型高分子等).ATRP技术与点击化学结合,可形成新的生物活性表面或者合成新的生物材料,可望产生更多的功能化的材料表面与生物材料.     

新型含偶氮苯生色团聚合物的制备和性能

合成了含手性碳原子的新型偶氮苯生色团,通过酰氯化反应制备出含偶氮苯生色团的单体,将所合成的单体与丙烯酸酯类单体进行自由基共聚得到以偶氮苯生色团为侧基的高分子.利用1H NMR、FTIR、UV-Vis吸收光谱,对所合成的单体及聚合物进行了结构表征.研究了所制备的聚合物的全光开关效应.结果表明,在激发光的照射下,通过聚合物中偶氮苯基团的顺-反-顺异构循环在聚合物材料中可形成光致各向异性;在较低驱动光功率(28.1 mW)下这种聚合物具有良好的全光开关效应.     

缩聚法制备热固性聚乳酸及其力学性能和热稳定性研究

以L-乳酸为单体、季戊四醇为引发剂,采用缩聚法合成了短链四臂星形聚乳酸(4sPLA),随后经不饱和酸酐对其端基改性,合成了含不饱和端基的四臂星形聚乳酸预聚物(M4sPLA),最后通过自由基引发M4sPLA的固化反应制备热固性聚乳酸,重点研究了缩聚时间对预聚物和热固性聚乳酸产物的影响。结果表明:延长缩聚时间可明显提高羟基引发效率和星形聚乳酸的分子量,降低杂质含量,使其分子量分布更窄;随直接缩聚时间的延长,固化产物具有更高的交联密度,经20 h直接缩聚的固化产物具有最好的力学性能、热稳定性以及完善的微观结构。     

聚(衣康酸丁二醇酯癸二酸丁二醇酯)的合成与表征

以衣康酸(IA)、癸二酸(SA)和1,4-丁二醇(BDO)为反应单体,采用熔融酯化缩聚法合成了一系列新型可生物降解脂肪族聚(衣康酸丁二醇酯癸二酸丁二醇酯)(PBIS)。采用核磁共振、凝胶渗透色谱、差示扫描量热、热失重分析和酶降解测试等方法对共聚酯的结构和性能进行了表征。凝胶渗透色谱测试结果表明,随着共聚酯中衣康酸含量的增加,其数均相对分子质量先减小后增大;差示扫描量热分析得出,产物的熔点和结晶温度随衣康酸含量的增加而下降;热失重分析表明,共聚酯拥有较好的热稳定性;酶降解测试得出共聚酯具有良好的生物降解性,且降解速率随衣康酸含量的增加而加快。     

侧链高分子液晶的合成与应用

侧链高分子液晶是近年来出现的新型液晶材料，可以用加聚、聚合物改性、缩聚、开环聚合等方法合成，是优良的信息材料和气相色谱固定液。本文对侧链高分子液晶研究的历史、国际与国内的发展现状作了综合评述。     

含杯芳烃单体及其聚合方法的研究进展

杯芳烃作为继冠醚和环糊精之后的第三代主体分子具有独特的分子离子识别能力和结构易修饰性.利用聚合物稳定性好、易于加工的特性将杯芳烃键合到聚合物上,有望制备出新型功能高分子材料.共聚法是一种制备含杯芳烃聚合物的重要方法,通过在杯芳烃上沿或下沿接上可聚合基团制备含杯芳烃单体,然后均聚或与其它单体共聚形成聚合物.主要阐述了含杯芳烃单体及其聚合方法的研究进展.     

高性能高分子材料新领域——I.重油聚合复合材料

文中提出了以重质油尤其是渣油分离的芳香分直接聚合成热固性(c-COPNA)或热塑性高聚物材料(t-COPNA)的方法,由此创建了高性能高分子材料原料的新来源与新领域,衍生出新一代耐高温、耐磨损、耐环境及多功能性专用料体系。与从原油裂化制备单体,再聚合成高聚物材料的传统路线相比,重油缩聚高分子材料技术路线具有综合效益高、环保性强而资源更加丰富的突出优点,对于应对能源危机、高分子原料不足的现状,有重大经济社会意义。     

高性能高分子材料新领域——I.重油聚合复合材料EI北大核心CSCD

文中提出了以重质油尤其是渣油分离的芳香分直接聚合成热固性(c-COPNA)或热塑性高聚物材料(t-COPNA)的方法,由此创建了高性能高分子材料原料的新来源与新领域,衍生出新一代耐高温、耐磨损、耐环境及多功能性专用料体系。与从原油裂化制备单体,再聚合成高聚物材料的传统路线相比,重油缩聚高分子材料技术路线具有综合效益高、环保性强而资源更加丰富的突出优点,对于应对能源危机、高分子原料不足的现状,有重大经济社会意义。     

磷酸基功能化二氧化硅材料的制备、性能和应用

近些年来,二氧化硅材料因低密度、低毒性、良好的生物相容性、优良的化学与热稳定性以及优异的形貌与结构的可控性而具有巨大的应用价值.对其进行改性,引入有机功能基,从而制备功能化二氧化硅材料有助于进一步提高其性能并扩展其应用范围.因优异的性能与潜在的应用价值功能化二氧化硅材料引起了众多研究者们的关注,而磷酸基功能化二氧化硅材料是其中的一个研究热点.本文归纳了磷酸基功能化二氧化硅材料的研究进展,对其制备及应用作了相关介绍.磷酸基功能化二氧化硅的制备方法主要包括磷酸硅烷偶联法和后磷酸化法.在磷酸硅烷偶联法中,基于磷酸硅烷的引入,分为后嫁接法与共缩聚法,其中后嫁接法主要是采用磷酸硅烷对二氧化硅材料进行改性,在材料表面形成硅氧硅键以引入磷酸基团;共缩聚法主要是磷酸硅烷与其他硅烷共同水解缩合,形成硅氧硅网络以引入磷酸基团.后磷酸化法中,基于反应中所形成的化学键,主要分为硅氧磷键法、碳磷键法、碳氧磷键法,其中硅氧磷键法是通过磷酸或磷酸衍生物对二氧化硅材料表面的硅羟基进行改性,通过形成硅氧磷键引入磷酸基团.碳磷键法主要是对功能化的二氧化硅进行Arbuzov反应或Mannich反应形成碳磷键以引入磷酸基团.碳氧磷键法主要是磷化试剂对环氧基功能化的二氧化硅进行改性,通过环氧开环反应,以形成碳氧磷键的方式引入磷酸基团.凭借磷酸基团优异的络合能力、充足的酸性位点、优异的质子自脱离能力、良好的生物活性以及二氧化硅本身优异的性能,磷酸基功能化二氧化硅材料在吸附、催化、电导、生物医学等方面具有优异的性能与广阔的应用价值.最后本文对磷酸基功能化二氧化硅材料未来的发展进行了展望.     

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