苯乙烯／马来酸酐共聚物的氢键诱导液晶体

制备了以苯乙烯／马来酸－４－羧基酚酯共聚物为质子供体,苯乙烯基吡啶为质子受体的氢键诱导液晶复合物。用ＤＳＣ和ＰＯＭ研究二者复合并后的液晶行为。结果表明,４ＳＺ含量在３０－７０％的复合物表现为向列相液晶态,其中等摩尔比的复合物的热稳定性提高。     

苯乙烯-马来酸酐接枝预聚物对PS版光敏涂层性能的影响

讨论了３ 种苯乙烯马来酸酐预聚物的结构和用量对 Ｐ Ｓ 版光敏涂层性能的影响。结果得出, 在相同用量情况下,苯乙烯马来酸酐接枝 Ｐ Ｅ Ｔ Ａ 预聚物（ Ｓ Ｍ Ｐ） 对涂层感度、显影性等性能的影响最显著。     

AAS/PA-6合金的相容性

用反应挤出法制备了一系列的尼龙６／苯乙烯丙烯酸丁酯丙烯腈共聚物（ＰＡ６／ＡＡＳ）合金的相容剂,采用透射电子显微镜（ＴＥＭ）观察了所得合金的微观形态,结合合金的力学性能,对所选用及所制备相容剂进行了筛选。结果表明,以ＳＥＢＳ与ＭＡＨ的接枝物作为相容剂（ＳＥＢＳ是苯乙烯,丁二烯的三嵌段共聚物）,或以ＳＥＢＳ的ＭＡＨ接枝物与ＳＭＡ（苯乙烯马来酸酐聚合物）作为复合相容剂,既可得到以粘度较高的ＡＡＳ为连续相且冲击强度很高的ＡＡＳ／ＰＡ６合金,也可以得到以ＰＡ６为连续相高冲击强度的ＰＡ６／ＡＡＳ合金。     

羧酸吡啶类氢键液晶分子的合成及表征

以4-己氧基苯甲酸为质子给体,4-硝基苯乙烯基吡啶为受体,四氢呋喃为溶剂,制备了一种液晶超分子复合物—羧酸吡啶类氢键自主装型液晶复合物,用DSC和热台偏光显微镜对所合成化合物进行了相态和液晶性研究,并用IR1、H-NMR对所合成化合物进行了结构表征。结果表明:合成了目标化合物;IR结果证明了羧基和吡啶环间分子间氢键代替了羧基间的分子间氢键;相态及液晶行为研究证明了氢键复合物具有典型的热致液晶性能且呈现明显的向列型液晶态。     

新型4-羟基苯乙烯基吡啶类氢键液晶的合成及表征

以4-羟基苯乙烯基吡啶为质子受体,以对烷氧基苯甲酸为质子供体,制备了几种苯乙烯基吡啶类氢键型液晶。利用IR和1H-NMR检测了各中间体。POM和DSC的结果表明,两种该氢键复合物呈现明显的向列相液晶态,IR结果证明了羧基和吡啶环间分子间氢键代替了羧基间的分子间氢键。     

含溴双官能团引发剂引发原子转移自由基嵌段共聚

合成了对二溴甲基苯作为原子转移自由基聚合的双官能团引发剂,以对二溴甲基苯／溴化亚铜／联吡啶（摩尔比１／２／４）为引发体系,进行极性单体甲基丙烯酸酯和非极性单体苯乙烯及不同的甲基丙烯酸酯之间的原子转移自由基段共聚,得到了实测分子量与设计分子量相近,分子量分布小于１．８的ＰＥＭＡ－ＰＳ－ＰＥＭＡ,ＰＢＭＡ－ＰＳ－ＰＢＭＡ,ＰＭＭＡ－ＰＢＭ－ＰＭＭＡ等多种三嵌段共聚物。     

三元无规全芳聚酯酰胺的热致液晶行为

由对苯二甲酰氯（ＴＰＣ）和二甲基联苯胺（ＤＭＢＤ）和双酚Ａ（ＢＰＡ）合成了三元无规全芳聚酯酰胺（ＰＥＡ）。用ＤＳＣ、Ｘ光衍射分析和偏光显微镜等手段表征了该类聚合物的热致液晶性质,确认了不同单体的比例的ＰＥＡ均为热致向列型液晶聚合物,且不出现液晶相转变温度直至聚合物分解。由于ＰＥＡ中聚酰胺链段之间的氢键作用,ＰＥＡ为熔融温度随ＤＭＢＤ的比例增加而升高,即使ＤＭＢＤ链单元为２０％（ｍｏｌ）的ＰＥＡ,其     

佳能EF28─105mmf／3．5─4．5USM变焦镜头使用体会

佳能ＥＦ２８─１０５ｍｍｆ／３．５─４．５ＵＳＭ变焦镜头使用体会蒋宁佳能（Ｃａｎｏｎ）ＥＦ２８－１０５ｍｍｆ／３，５－４．５ＵＳＭ变焦镜头是佳能公司配合３５ｍｍ自动聚焦单反相机ＥＯＳＳ（在欧美市场上该机型号为眼控聚焦的ＥＯＳＡＺＥ和非眼控聚焦的ＥＯＳ...     

PES与热致液晶高分子共混物的流变性能

研究了ＰＥＳ与热致液晶聚合物（ＬＣＰ）ＨＢＡ／ＰＥＴ（６０／４０）共混物的转矩流变和剪切流变性能。加入２％～５％ＨＢＡ／ＰＥＴ（６０／４０）可使ＰＥＳ熔体在低剪切速率下的表观粘度下降２～４倍。共混物的粘流活化能也低于纯ＰＥＳ的活化能。加入少量ＬＣＰ（５％以下）可望大大改善ＰＥＳ的加工性能。     

两种新型氢键诱导液晶材料的合成及表征

以对氨基苯甲酸、对硝基苯甲醛和吡啶衍生物为原料合成了两种新型氢键诱导液晶。用IR、1H-NMR和元素分析对所合成的化合物进行了结构表征,并用DSC和带热台的偏光显微镜分别对质子供体和超分子复合物复合前后的液晶行为进行了研究。结果表明:合成了目标化合物;IR结果证明了羧基和吡啶环间分子间氢键代替了羧基间的分子间氢键,复合物表现出分子的热力学行为;液晶行为研究证明了氢键复合物是典型的热致液晶且呈现明显的向列型液晶态,超分子液晶复合物较质子供体的液晶相范围宽且其相转变温度低于质子供体,说明分子间氢键起到了稳定液晶相态的作用。     

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.