LP—15聚酰亚胺复合材料工艺特性研究

本文介绍了ＬＰ－１５聚酰亚胺树脂的贮存性能以及在不同压力下树脂的流动性，讨论了树脂流动性和复合材料成型工艺性之间的关系。     

PMR—15聚酰亚胺及其复合材料的研究进展

本文综述了ＰＭＲ－１５聚酰亚胺的发展历史，树脂及复合材料的性能和应用，树脂及复合材料尚待改进和研究的问题等。     

高韧性PMR聚酰亚胺复合材料树脂基体的研究

本工作以ＯＤＰＡ取代ＰＭＲ－１５中的ＢＴＤＥ即以ＯＤＰＡ，ＭＤＡ，ＮＥ作为复合材料对脂基体，对纤维存在下的该树脂基体的的反应性及复合材料的制备和性能测试进行了研究。实验结果表明，同ＰＭＲ－１５相比，该树脂基体具有更优的反应性，该树脂基体复合材料具有更优的层间断裂韧性。     

PMR—1及其复合材料的发展与应用

综述了耐高温聚酰亚胺ＰＭＲ－１５的组成及化学性能，预浸料及复合材料的制造、性能及应用，并对ＰＭＲ－１５的发展情况作了介绍。     

PMR－15及其复合材料的发展与应用

综述了耐高温聚酰亚胺ＰＭＲ－１５的组成及化学性能、预浸料及复合材料的制造、性能及应用，并对ＰＭＲ－１５的发展情况作了介绍。     

阳极氧化对高聚物基碳纤维复合材料界面性能的影响

采用阳极氧化法对Ｔ－３００高强度碳纤维和Ｍ－４０高模量碳纤维进行了表面处理。发现该方法能剥除Ｔ－３００碳纤维表面的高涂层，涂覆耐热涂层后可提高Ｔ－３００／聚酰亚胺复合材料界面的抗热氧化性能，并且可使基体改性的珠Ｍ－４０／酚醛环氧复合材料界面强度和冲击强度同时获得提高。     

聚酰亚胺纤维增强树脂基复合材料的研究

以聚酰亚胺纤维为增强体,环氧树脂、双马来酰亚胺树脂、氰酸酯和聚酰亚胺树脂为基体,通过模压成型法制备了4种聚酰亚胺纤维增强的树脂基复合材料。研究了4种基体树脂低聚物的固化行为和流变性能,并表征了4种相应树脂基复合材料的热学、力学、介电性能以及纤维与树脂之间的界面性能。结果表明:4种基体树脂低聚物最低黏度都低于15Pa·s,显示了良好的成型工艺性,环氧树脂基复合材料的力学性能最好,弯曲强度、弯曲模量和层间剪切强度分别达到716MPa、54.9GPa和56.5MPa;聚酰亚胺树脂基复合材料的耐热等级最高,玻璃化转变温度大于300℃;氰酸酯树脂基复合材料的介电性能最优,介电常数在低频段低于3.3。     

LP-15 聚酰亚胺复合材料研究

LP-15 聚酰亚胺是新一代不含MDA 的PMR 聚酰亚胺树脂体系。作为复合材料树脂基体,LP-15 聚酰亚胺具有优异的成型工艺性, 较好的抗热氧化稳定性, 优良的综合力学性能及耐冷热疲劳性能, 可在280℃下替代PMR-15 复合材料长期使用。     

苯炔基封端的联苯型聚酰亚胺复合材料

采用改性单体原位反应聚合法(MPMR) 制备了苯炔基封端的聚酰亚胺树脂, 采用模压方法研究了聚酰亚胺复合材料的成型工艺。所制备的树脂和复合材料均具有很高的热稳定性; 复合材料在371 ℃的力学性能保持率高于室温力学性能的50 %; 其玻璃化转变温度为449 ℃; 纯树脂和复合材料在371 ℃空气中100 h 的热失重小于3 %。所研制的聚酰亚胺复合材料基本满足了371 ℃高温树脂的性能。      

RTM聚酰亚胺复合材料力学性能研究

研究RTM聚酰亚胺树脂的流变学和凝胶行为,确定该树脂的复合材料成型工艺参数,测试其复合材料的室温和高温力学性能.结果表明:RTM聚酰亚胺树脂在高温下具有良好的流变性能,在260～280℃之间有较长的开放期,可以实现RTM工艺.RTM聚酰亚胺复合材料具有较高的玻璃化转变温度、良好的室温力学性能和优异的高温(288℃)力学性能保持率,可以低成本(RTM)地制造耐高温的聚酰亚胺复合材料.     

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.