共查询到20条相似文献,搜索用时 625 毫秒
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为了进一步提高环氧树脂的阻燃性能,采用微流控技术制备了以乙氧基化三羟甲基丙烷三丙烯酸酯(ETPTA)为壳,高效磷-氮阻燃剂(FR-PN)为芯材的FR-PN@ETPTA阻燃微胶囊,并将其运用于环氧树脂(EP)中;对比了FR-PN/EP、FR-PN@ETPTA/EP的热稳定性、阻燃性能和力学性能;探讨了FR-PN@ETPTA阻燃微胶囊对EP的燃烧性能和热降解行为的影响,揭示了FR-PN@ETPTA阻燃微胶囊的阻燃机制。试验结果表明:FR-PN@ETPTA阻燃微胶囊能够改善EP的阻燃性能,当阻燃微胶囊添加量为10wt%时,树脂的极限氧指数(LOI)值增加至37.3%,UL-94等级达到V-0级。环氧树脂中添加FR-PN阻燃剂或FR-PN@ETPTA阻燃微胶囊会降低树脂的拉伸性能和弯曲性能,但加入阻燃微胶囊试件的拉伸性能和弯曲性能优于加入阻燃剂的试件,且添加10wt%阻燃微胶囊后,树脂的冲击强度比纯EP增加了39%。研究表明,阻燃微胶囊改性环氧树脂的阻燃机制是气相阻燃与凝聚相阻燃相结合。 相似文献
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多层织物系统综合热防护性能 总被引:2,自引:0,他引:2
研究了消防服用多层织物系统的综合热防护性能.将耐高温阻燃织物Nomex、Kermel和芳砜纶织物与PTFE、TPU和三维阻燃间隔织物组合,模拟消防服的层次构成,通过垂直燃烧实验测试分析了外层织物的阻燃性能,通过TPP(热辐射和热对流综合热防护性能)实验测试分析了多层织物系统的综合热防护性能.研究得出:热防护性最大的织物组合是芳砜纶、三维阻燃间隔织物和阻燃棉布;最适宜用于消防服的织物组合是NomexⅢ A、三维阻燃间隔织物和阻燃棉布;可将三维阻燃间隔织物用于消防服结构组成中,有助于减轻消防员的热负荷. 相似文献
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本文研究了SY928系列无机复合阻燃消烟剂改性PVC的性质,报道了其阻燃性能,讨论了无机复合阻燃消烟剂的用量、聚氯乙烯制品中增塑剂的含量以及表面改性对阻燃性能测试结果的影响。检测结果表明,阻燃性能已严格于相应国家标准,达到难燃材料B1级。 相似文献
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温拌阻燃OGFC沥青混合料功能研究 总被引:1,自引:1,他引:0
针对隧道沥青路面应用特性,分别制备了新型温拌改性剂及阻燃改性剂.以关键孔径2.36 mm通过率为特征点,确定了OGFC沥青混合料配合比,并进行路用性能检验,全面研究了温拌阻燃OGFC沥青混合料的抗滑功能、降噪功能、低温施工功能以及阻燃功能.基于红外光谱和热重试验,深入研究温拌阻燃OGFC低温施工机理及阻燃机理.同时从OGFC级配特性出发,揭示OGFC沥青混合料抗滑降噪机理.结果表明:温拌阻燃剂可改善沥青混合料高温性能以及水稳定性能,对低温性能影响较小,且温拌阻燃OGFC沥青混合料路用性能均满足规范要求,其抗滑、降噪功能以及阻燃功能显著.温拌改性沥青混合料可用于低温环境下的施工. 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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Steffen Müller-Probandt 《材料科学与工程:中英文B版...》2018,(4):161-177
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... 相似文献
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A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils. 相似文献
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Janet Lang 《Materials and Manufacturing Processes》2017,32(7-8):857-866
ABSTRACTThe 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. 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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S. K. Malhotra Paramanand Singh A. Thirunavukkarasu 《Materials and Manufacturing Processes》2006,21(7):652-657
Al2O3-ZrO2 nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness. 相似文献
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The end of over unit products of more than Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits beer wine yellow wine fruit syrup wine others cover over % of the national top-branded liquor products.…… 《中国标准化(英文版)》2008,25(1):30
The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.…… 相似文献
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Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster. 相似文献