共查询到20条相似文献,搜索用时 62 毫秒
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为研究包覆硝酸铵(AN)发射药的吸湿问题,用硝化棉(NC)对不同AN含量的AN发射药进行了不同层数的包覆,然后对未包覆和包覆试样进行了平衡干燥器法吸湿测试和真空安定性试验。结果表明:在温度为30℃、相对湿度为90%的条件下,AN发射药的吸湿量随着AN含量的增加而增加;包覆层有效抑制了吸湿性,提高了AN发射药的安定性。 相似文献
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EI发射药的燃烧特性 总被引:1,自引:0,他引:1
为研究EI发射药的燃烧性能,基于EI发射药的制备过程及药形结构特征,对EI发射药的浸渍层分布、燃烧过程中药型尺寸及能量特性的变化进行了理论分析和实验验证.建立了EI发射药的燃速计算数学模型.制备了NG浸渍量分别为10%和15%的EI-1和EI-2样品.进行了密闭爆发器试验、显微切片照相.结果表明,NG浸渍量为15%时,火药力提高了10.14%,浸渍深度为0.168 mm;根据实验数据计算EI发射药的u-p曲线,150 MPa前EI发射药的燃速高于单基发射药,在150 MPa后两者重合;由L-B曲线知EI-2发射药的燃烧渐增性较好.只要NG浸渍量和聚酯浸渍量配比合适,EI发射药的火药力和燃烧渐增性在一定范围内可以同步增加. 相似文献
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窄通道杆状发射药内孔燃气流动数值模拟 总被引:1,自引:0,他引:1
运用合理的简化假设,建立杆状发射药内孔通道燃气流动模型,利用Fluent软件求解器对长径比为40的某一特定单孔杆状发射药燃气在内孔的流动过程进行了数值模拟,在给定初始压力和温度的条件下模拟内孔燃气的速度分布及压力分布,并进行分析。结果表明,径向由孔中心到孔壁,燃气流速逐渐减小,压力逐渐增大;轴向燃气流速先逐渐减小,压力先逐渐增大,在10mm处突然形成速度和压力的震荡波,并随时间沿轴向传递,5ms后速度趋于平稳波动,压力整体保持波动并持续上升,但各点压力最终都保持稳定。 相似文献
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Silicon - The aim of this research work is to study the effects of non-uniform emitter sheet resistance on the performance of PERC solar cells. For this purpose, we used different simulation... 相似文献
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利用TCAD半导体器件仿真软件对N型插指背接触(Interdigitated Back Contact,IBC)单晶硅太阳电池发射区半宽度进行研究,全面系统地分析了在不同背表面复合速率的情况下,发射区半宽度对IBC太阳电池短路电流密度(JsC)、开路电压(VOC)、填充因子(FF)及转换效率(Eff)的影响.结果表明:随着背表面复合速率的增大,对于不同发射区半宽度的情况,IBC太阳电池JSC、VOC、FF及Eff均显著降低.当背表面复合速率一定时,发射区半宽度越大,JSC、VOC越高,而FF越低.随着发射区半宽度的增大,IBC太阳电池Eff呈现先增大后减小的变化特点.当背表面复合速率较小(50~500 cm/s)时,最优的发射区半宽度为800 μm.当背表面复合速率较高(≥5000 cm/s)时,最优的发射区半宽度为1200 μm. 相似文献
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A symmetrical approach is suggested (Chang DE et al. Nat Phys 3:807, 2007) to realize a single-photon transistor, where the
presence (or absence) of a single incident photon in a ‘gate’ field is sufficient to allow (prevent) the propagation of a
subsequent ‘signal’ photon along the nanowire, on condition that the ‘gate’ field is symmetrically incident from both sides
of an emitter simultaneously. We present a scheme for single-photon transistors based on the strong emitter-surface-plasmon
interaction. In this scheme, coherent absorption of an incoming ‘gate’ photon incident along a nanotip by an emitter located
near the tip of the nanotip results in a state flip in the emitter, which controls the subsequent propagation of a ‘signal’
photon in a nanowire perpendicular to the axis of the nanotip. 相似文献
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设计了一种新的梯度组分分布数学模型,采用梯度因子和梯度层数控制梯度组分的分布,并采用逐层浇铸的方法制备了不同层数的EP/PU梯度互穿网络聚合物(IPN)材料;测试了材料的拉伸性能、弯曲性能以及冲击性能;研究了梯度层数变化对这些性能的影响,并同普通IPN的性能进行了对比。研究结果表明,在相同质量比和梯度因子情况下,梯度层数越多,拉伸强度和冲击强度越高,弯曲强度越低。梯度IPN的拉伸强度和冲击强度均高于普通IPN,弯曲强度低于普通IPN。 相似文献
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Gradient polymers are multicomponent polymers whose structures or compositions are not macroscopically homogeneous, but vary as a function of position in the sample. One method to prepare such polymers is by diffusing a guest monomer into a host polymer and then polymerizing the monomer in position to retain the concentration gradient created by the diffusion. One series of such type of materials was prepared by diffusing acrylonitrile into polystyrene. The gradient profile was determined by analyzing the nitrogen content in succeeding layers of the sample. These gradient polymers exhibit improved resistance to hydrocarbon solvents. The second series of gradient polymers was made by diffusion of methyl acrylate into poly(methyl methacrylate). These materials are shown to possess substantially increased fracture strain. Eyring's stress-biased activated rate theory of yielding was used to rationalize the observed toughening effect in gradient polymers. 相似文献
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Jan Genzer 《The Journal of Adhesion》2013,89(3-4):417-435
One of the most versatile and widely used methods of forming surfaces with position-dependent wettability is that conceived by Chaudhury and Whitesides more than a decade ago [Science 256, 1539 (1992)]. In this paper we review several projects that utilize this gradient-forming methodology for: controlled of deposition of self-assembled monolayers on surfaces, generating arrays of nanoparticles with number density gradients, probing the mushroom-to-brush transition in surface-anchored polymers, and controlling the speed of moving liquid droplets on surfaces. 相似文献