共查询到20条相似文献,搜索用时 726 毫秒
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已发现三苯胺基和苯并(噁)唑是优良的有机共轭发光材料电荷传输基团.将三苯胺基作为空穴传输基团和苯并(噁)唑作为电子传输基团引入均二苯乙烯分子中,设计并合成了四个新双极小分子发光物质4-二苯氨基-4‘-(2-苯并(噁)唑)均二苯乙烯.通过光谱分析和元素分析等方法确认了其化学结构.所合成化合物的相关分析结果表明化学结构、取代基效应、溶剂环境等因素对其UV-Vis光谱、荧光光谱、荧光量子产率、电致发光谱和启亮电压都产生一定的影响. 相似文献
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设计并合成了一系列含有苯并噁唑环和不同CH2链长的刚、柔间隔聚亚甲基苯并二噁唑(PBOCx)聚合物,并对它们进行了结构表征,同时对聚合物的溶解性能和热性能进行了探讨.研究表明,在主链上引入亚甲基结构可以在一定程度上提高聚合物的溶解性,其中PBOC4显示了良好的溶解性能,但随着亚甲基数目的增加,聚合物的溶解性能有下降趋势;虽然有柔性链段的引入,分解温度降低,但是PBOCx仍具有很高的热分解温度,在450℃以下表现出良好的热稳定性. 相似文献
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RTM改性苯并噁嗪树脂及复合材料性能研究 总被引:1,自引:0,他引:1
研究了RTM改性苯并噁嗪树脂及复合材料性能.用DMA研究RTM改性苯并噁嗪树脂体系的储能模量、损耗模量和玻璃化转变温度;用流变仪研究黏度特性;用TGA和TGA微分曲线研究热分解性能;并研究了RTM改性苯并噁嗪树脂及复合材料的力学性能.结果表明:RTM改性苯并噁嗪树脂体系的玻璃化转变温度是206℃;至少有400min的低黏度(η≤0.5Pa.s)时间作为工艺开放期;在氮气气氛下,RTM苯并噁嗪树脂体系热失重分两个主要阶段,在375℃时发生5%热失重,800℃残碳率是45.2%;RTM苯并噁嗪树脂基体拉伸强度72.4MPa,拉伸模量5.07GPa,弯曲强度173MPa,弯曲模量4.6GPa;碳纤维增强RTM苯并噁嗪树脂基复合材料的常规力学性能优异. 相似文献
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氧化石墨烯(GO)具有良好的耐热性和力学性能,可用于制备树脂基纳米复合材料,对树脂具有独特的改性效果,但分散性差却限制了GO对树脂基复合材料更好的改性效果。采用超支化聚硼酸酯(HBPB)与GO接枝得到氧化石墨烯-超支化聚硼酸酯(GO-HBPB),并将其用于双环苯并噁嗪树脂(B-BOZ)改性,不仅可解决GO分散性差的问题,还可利用GO-HBPB优异的耐热性,超支化结构,以及大量酚羟基端基对B-BOZ树脂噁嗪环的催化开环作用,使得GO-HBPB改性B-BOZ树脂(BOZ-GO-HBPB)具有比B-BOZ树脂更低的固化温度,在800℃(N2)下高达58.7%的残碳率,以及粗糙而柔韧的树脂浇注体断面形貌。 相似文献
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《International journal for numerical methods in engineering》2018,113(9):1488-1506
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. 相似文献
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Standards are the basis for production enterprises to organize production ex-factory inspection trade 《中国标准化(英文版)》2008,25(1):24-25
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.…… 相似文献
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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. 相似文献
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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.…… 相似文献
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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. 相似文献
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C. Qihong W. Zhan‐Wen J. Yi J. Yehua L. Fei F. Hanguang 《Materialwissenschaft und Werkstofftechnik》2014,45(7):582-590
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. 相似文献
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《中国标准化(英文版)》2014,(4)
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 相似文献
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《中国标准化(英文版)》2014,(5)
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. 相似文献
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《中国标准化(英文版)》2014,(4)
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 相似文献