排序方式: 共有52条查询结果,搜索用时 15 毫秒
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硝基甲烷在离子液体BMImBF4中的电还原特性 总被引:1,自引:0,他引:1
采用循环伏安等测试方法, 以铂微盘电极为工作电极, 研究了硝基甲烷在离子液体1-正丁基-3-甲基咪唑四氟硼酸盐(BMImBF4)中的电化学行为, 并探讨了温度和扫描速率等因素对硝基甲烷电化学特性的影响. 实验结果表明, 硝基甲烷在离子液体BMImBF4中的还原反应是受扩散控制的不可逆过程. 估算了不同温度下硝基甲烷在离子液体BMImBF4中的扩散系数D, 进而求得它的扩散活化能Ea约为39.5 kJ·mol-1. 相似文献
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Human coagulation Factor V(FV), together with Factor Xa, assembles to prothrombinase complex on activated cell surface, which converts prothrombin into thrombin, leading to fibrin deposition. The C2 domain of FV is believed to be a primary anchor for the assembly of pro- thrombinase on the cell surface, and was proposed as a target to intervene with pathological thrombotic events. We report here the crystal structure of the C2 domain of FV fused to maltose-binding protein(MBP). The fusion tag of MBP is critical to generate the crystal for this study. There is no strong interaction between MBP and FVC2. The overall structure of FVC2 is similar to the previous FVC2 structures, suggesting the MBP fusion does not perturb the molecular structure of FVC2. This crystal form of FVC2 can be used for future study of molecular interaction between FVC2 and its inhibitors. 相似文献
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如何确定精确的原子间作用势一直是模拟计算的重要基础问题. 以面心立方金属金和银为对象, 采用第一性原理方法, 分别得到金和银的晶格内聚能-原子距离曲线及基态原子能曲线. 根据陈-莫比乌斯(Chen-Möbius)晶格反演理论和自编程序, 得到了精确的反演对势曲线. 对该曲线进行拟合, 通过比较不同势函数的拟合结果, 提出了双指数型的势函数解析式, 并得到具有全局性且高精度的拟合效果. 为了验证反演势的有效性, 利用反演势结果计算了金和银的声子谱并与Sutton-Chen提出的嵌入原子势和第一性原理计算得到的声子谱做比较. 分析表明, 反演势能够合理反映原子间的相互作用. 最后, 利用得到的结果, 计算了金和银的热膨胀系数和弹性模量等物理量, 计算结果与实验数据基本符合, 表明构建的金和银的反演势是准确有效的. 相似文献
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Estimation of the proton energy spectrum in knee region by analog read-out of ARGO-YBJ experiment 总被引:1,自引:0,他引:1
Based on the six months data set of ARGO-YBJ experiment with analog read-out and its Monte Carlo simulation, we study the difference between different primaries induced showers by using the space-time information of the charged particles in Extensive Air Showers. With five parameters which can efficiently pick out primary proton induced showers as inputs of an artificial neural network, the proton spectrum from 100 TeV to 10 PeV can be obtained. 相似文献
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The Large High Altitude Air Shower Observatory (LHAASO) project is proposed to study high energy gamma ray astronomy (40 GeV--1 PeV) and cosmic ray physics (20 TeV--1 EeV). The wide field of view Cherenkov telescope array, as a component of the LHAASO project, will be used to study the energy spectrum and composition of cosmic rays by measuring the total Cherenkov light generated by air showers and the shower maximum depth. Two prototype telescopes have been in operation since 2008. The pointing accuracy of each telescope is crucial for the direction reconstruction of the primary particles. On the other hand, the primary energy reconstruction relies on the shape of the Cherenkov image on the camera and the unrecorded photons due to the imperfect connections between the photomultiplier tubes. UV bright stars are used as point-like objects to calibrate the pointing and to study the optical properties of the camera, the spot size and the fractions of unrecorded photons in the insensitive areas of the camera. 相似文献
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为了探索具有优异吸能性能的软基体混合胞孔材料的力学性能,研究该类材料在多次冲击下的冲击响应和材料的可恢复性,对一种软基体混合胞孔材料—人工软骨仿生超材料(artificial cartilage foam,ACF)进行了不同速度下的单轴拉伸和压缩实验,得到了ACF材料在不同应变率条件下的应力-应变曲线。并利用落锤冲击实验机对ACF材料和另一种软基体混合胞孔材料—发泡聚丙烯材料(expanded polypropylene,EPP)进行了多次冲击下的对比测试,得到了2种材料在单次和多次冲击下的动力学响应。实验结果表明:ACF材料是一种应变率敏感的材料,随着应变率的提升,材料的弹性模量、抗拉强度和抗压强度均逐渐提高;在50 J 冲击能量作用下,ACF材料能够吸收96%以上的冲击能量,远高于EPP材料的70%,ACF材料具有更加优异的吸能性能;5次冲击后ACF材料的最大峰值力、最大变形量和吸能能力几乎不变。相比于EPP材料,ACF材料有良好的可恢复性,且具有稳定的多次抗冲击能力。这些研究为软基体混合胞孔材料在多次冲击防护中的应用提供了实验依据。 相似文献
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MGRO J2019+37,within the Cygnus region,is a bright extended source revealed by Milagro at 12-35 TeV.This source is almost as bright as the Crab Nebula in the northern sky,but is not confirmed by ARGO-YBJ around the TeV scale.Up to now,no obvious counterpart at low energy wavelengths has been found.Hence,MGRO J2019+37 is a rather mysterious object and its VHEγ-ray emission mechanism is worth investigating.In this paper,a brief summary of the multi-wavelength observations from radio toγ-rays is presented.All the available data from XMM-Newton and INTEGRAL at X-ray,and Fermi-LAT atγ-ray bands,are used to get constraints on its emission flux at low energy wavelengths.Then,its possible counterparts and the VHE emission mechanism are discussed. 相似文献