MCM-41 填加量与偶联修饰对复合材料拉伸性能的影响

通过溶液共混法制备出MCM-41/ 环氧树脂、偶联修饰MCM-41/ 环氧树脂纳米复合材料。研究了填充MCM-41 介孔分子筛颗粒的偶联修饰以及不同的填充颗粒含量对分散性和复合材料拉伸性能的影响。结果表明: 在MCM-41/ 环氧树脂纳米复合材料中, MCM-41 仍保持着长程有序的孔道结构。修饰后的MCM-41 变成亲油性, 有利于增强颗粒与环氧树脂间的界面结合和纳米网络结构的形成, 使MCM-41 颗粒更能均匀分散在聚合物基体中, 提高复合材料的拉伸性能。修饰后的MCM-41 填加量为2.5 %(质量分数) 时, 拉伸强度达到最大值,比基体树脂提高99.2 % , 杨氏模量提高了110 %。      

钼改性酚醛树脂的制备与表征

采用钼改性酚醛树脂（PF），结果表明，钼改性PF的耐热性比纯PF有明显提高，当钼含量为5％时，合成的PF耐热性最好，初始分解温度约为362℃，比纯PF提高112℃；切线法得到的外延分解温度约为410℃，比纯PF升高了117℃；500℃时失重约38％，比纯PF有明显提高；红外光谱表明钼元素以钼氧键的形式引入到PF结构中。     

不同结构的颗粒填充对环氧树脂纳米复合材料性能的影响

通过溶液共混法制备了环氧树脂/纳米介孔MCM-41和环氧树脂/纳米SiO2复合材料,研究了结构不同的填充颗粒、不同的填充颗粒含量及其复合材料的分散性与力学性能.结果表明,由于这种具有双重纳米结构(纳米级颗粒尺寸和纳米级的介孔结构)的介孔分子筛MCM-41能与基体形成新型网络复合结构,因此在纳米介孔MCM-41的含量适当(小于10%,质量分数,下同)时,纳米介孔MCM-41能均匀地分散在环氧树脂基体中,有效地提高复合材料的拉伸强度.而含量较高(不低于5%)的实心纳米SiO2将在环氧树脂基体中产生大量团聚体,使复合材料的拉伸强度降低.     

超临界CO2方法制备环氧树脂/纳米介孔MCM-41复合材料

采用超临界方法先将环氧树脂低聚物引入介孔MCM-41的一维孔道内,再与基体溶液共混,制备出环氧树脂／MCM-41纳米复合材料．研究了复合材料的拉伸性能与填充复合颗粒含量的关系．结果表明,超临界的方法确实可将环氧树脂低聚物分子链引入到MCM-41的孔道,并占据孔道的绝大多数空间．环氧基团进入介孔的孔道中并使孔口处的环氧基团与基体环氧产生了较强的界面相互作用,增加了两者的相容性．填充含量较低的复合颗粒就能提高复合材料的拉伸性能．     

钼改性酚醛树脂的制备与表征

采用钼改性酚醛树脂(PF),结果表明,钼改性PF的耐热性比纯PF有明显提高,当钼含量为5%时,合成的PF耐热性最好,初始分解温度约为362℃,比纯PF提高112℃;切线法得到的外延分解温度约为410℃,比纯PF升高了117℃;500℃时失重约38%,比纯PF有明显提高;红外光谱表明钼元素以钼氧键的形式引入到PF结构中。     

硅烷修饰对环氧树脂/纳米介孔MCM-41复合材料性能的影响

用偶联剂将纳米介孔MCM-41粉体修饰后与环氧树脂溶液共混,制备出环氧树脂/MCM-41纳米复合材料.研究了偶联剂的含量和不同溶剂的修饰对纳米介孔MCM-41粉体分散性和复合材料力学性能的影响.结果表明,加入适量的偶联剂和在极性较小的介质中修饰,可制备出单分散的纳米介孔MCM-41颗粒增强的新型网络复合材料.偶联剂中的有机基团-(CH2)3-NH2不仅进入孔道、修饰了MCM-41的孔壁,而且使介孔分子筛保持了有序的孔道结构.环氧树脂高分子链与偶联修饰后的MCM-41颗粒的内、外表面以强烈的化学键结合,使MCM-41颗粒均匀分散在聚合物基体中,提高了材料的力学性能,其拉伸强度比基体树脂提高了69%,杨氏模量提高了90%.     

UP/Na-MMT纳米复合材料的制备与性能

研究了UP／Na-MMT纳米复合材料的制备与性能，并考察了插层剂种类、有机蒙脱土加入量及离子交换量对复合材料性能的影响。结果表明，UP／Na-MMT纳米复合材料的XRD曲线中蒙脱土晶体结构的布拉格衍射峰已经消失，说明其晶层已被树脂撑开，达到纳米级分散；复合材料的耐热性能得到明显改善，其冲击强度和拉伸强度均有较大提高。     

石墨烯/酚醛树脂纳米复合材料的热解行为

将氧化石墨烯与自制酚醛树脂乳液(PF)共混,经水合肼还原和热固化制备石墨烯/酚醛树脂(GNS/PF)纳米复合材料。利用AFM、SEM、FTIR和TG-DTG技术考察石墨烯对GNS/PF复合材料的形貌、结构、热稳定性和残炭率的影响。结果表明,石墨烯片均匀分布在PF中,没有发生团聚,且石墨烯片与PF间具有良好的界面结合。石墨烯薄片对PF基体强烈的吸附作用增加了PF分子链的活性和有序性,显著提高了GNS/PF纳米复合材料内PF基体的固化交联密度,进而提高了PF基体的耐热性和高温残炭率。在300~450℃条件下,纯酚醛树脂的热分解峰值温度为382.7℃,添加质量分数0.65%的GNS后,热分解峰值温度提高到408℃。在隔绝空气下900℃热处理,纯酚醛树脂的残炭率为46.2%,添加0.65%氧化石墨烯后残炭率增至59.4%,提高了13.2%。     

桐油改性酚醛树脂的耐热性研究

本文对桐油改性酚醛树脂的一些性能进行了研究，并着重利用ＤＴＡ、ＴＧ热分析技术研究了这类改性树脂的耐热性能及其热分解动力学。实验结果表明，桐油改性酚醛树脂的热分解分为两个阶段：第一个分解峰为４５０～４９０℃，约分解３０～４５％；第二个分解峰为５７０～６７０℃，约分解３５～５５％。随着甲醛／苯酚摩尔比的增加，初始分解温度逐渐升高。这种经桐油改性的酚醛树脂耐热性能可达：初始分解温度３５９．４～３８３．７     

一种适用于树脂传递模塑工艺的双马来酰亚胺改性酚醛树脂

合成了一种双马来酰亚胺改性酚醛树脂，研究了加工性能，固化树脂的力学性能和耐热性。应用一种高温固化剂于该树脂体系中，并探讨了它对树脂性能的影响。制备了这类树脂与玻璃布的复合材料，评价了不同温度下的力学性能。结果表明，改性树脂具有适用于RTM工艺的良好加工性能，高温固化剂的使用能较大幅度地提高树脂的耐热性。在300℃下，复合材料的弯曲强度和保持率分别为73％和83％。     

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.     

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.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to