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二维等离子体模拟粒子云网格方法的并行计算与性能分析 总被引:5,自引:0,他引:5
在共享和分布式存储两种并行计算环境下,组织了二维等离子体模拟粒子云网格法程序(2DCIC)的并行计算。首先,通过分析串行算法和2DCIC程序的单机执行特征,设计了并行算法和实现策略;然后,基于共享存储和消息传递现任中并行程序设计方式,在四种共享和颁式存储并行机上,组织了具体的并行计算,对性能结果进行了的比较分析,获得也若干重要的结论。 相似文献
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为了更加便捷地对电动汽车进行程序更新和故障诊断,开发了符合ISO15765的底层刷写协议栈。参考BOSCH ECU在线刷写流程拟定XC2000刷写流程,包括初始化、密钥认证、Flash分区擦除、Flash分区写入等过程。开发XC2000 Flash驱动,实现Flash按地址进行块擦除和写入,开发Bootloader,实现硬件资源初始化以及ISO15765协议栈的装载。开发了符合ISO15765的底层刷写协议栈,实现故障码读取、故障码清除、数据流读取、执行器测试等故障诊断功能。开发了电动汽车诊断上位机系统,并通过硬件在环仿真测试平台进行测试。测试结果表明,设计的电动汽车诊断系统利用CAN总线能够实现ECU在线刷写及故障诊断功能。 相似文献
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石墨烯力学性能的研究对其在半导体技术中的应用是十分重要的,本文基于半连续体模型并结合石墨烯纳米结构特性,通过对原子的描述构建了石墨烯形变分量和位移分量的新关系,从而给出了单层石墨烯结构形变能,并计算了不同尺寸单层石墨烯的杨氏模量值.通过对不同方向杨氏模量的分析,讨论了单层石墨烯的手性行为.结果表明:随着尺寸的增加,单层石墨烯两个方向的杨氏模量分别趋于0.746 TPa和0.743 TPa,当尺寸相同时,两方向杨氏模量的最大差值不超过0.003 TPa,此结果与文献报道结果相符.在小应变情况下,单层石墨烯薄膜呈各向同性,且薄膜尺寸变化对该特性影响不大.该计算结果对研究石墨烯的其它力学特性提供一定的参考价值. 相似文献
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本文利用基于GW方法和Bethe-Salpeter方程的第一性原理计算,研究了两种二维共价有机骨架材料(COF)的激发态性质. 单层COF是直接带隙材料,而体相COF呈现间接带隙. 根据直接激子计算的体相COF的光学带隙和吸收光谱与实验一致,而由位于导带底的光生电子和位于价带顶的空穴形成的间接激子能量的理论计算值远低于实验荧光光谱的测量值. 研究表明,可以排除间接带隙COF材料的发光由声子主导的可能性. 研究认为体相COF的发光可能源于缺陷处直接激子的复合. 体相COF的AA堆叠结构导致其带隙是间接的. 如果将堆叠方式由AA变成AB,体相COF将转变成直接带隙材料,它的发光效率可能会增强. 相似文献
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利用密度泛函理论结合非平衡格林函数方法,研究了不同拓扑能带结构的石墨烯电极分子器件输运特性.结果表明器件导通电压与电极禁带宽度正相关,同时器件在输运过程中表现出负微分电阻特性,峰谷电流比可达2697.分析认为器件导通源自于偏压升高过程中两电极能带匹配.器件负微分电阻特性源自于偏压升高过程中两电极能带交错.散射态分析表明,能带匹配后散射态分布较为离域,有利于电子通过器件.能带交错后散射态局域于电极处,表明电子输运受到抑制. 相似文献
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We present the behaviors of both dynamical and static charge susceptibilities of undoped armchair graphene nanoribbon using the Green's function approach in the context of tight binding model Hamiltonian.Specifically,the effects of magnetic field on the the plasmon modes of armchair graphene nanoribbon are investigated via calculating the correlation function of charge density operators.Our results show that the increase of magnetic field makes the high-frequency plasmon mode for both metallic and insulating cases disappear.We also show that low-frequency plasmon mode for metallic nanoribbon appears due to increase of magnetic field.Furthermore,the number of collective excitation modes increases with ribbon width at zero magnetic field.Finally,the temperature dependence of the static charge structure factor of armchair graphene nanoribbon is studied.The effects of both magnetic field and ribbon width on the static charge structure factor are discussed in detail. 相似文献
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R. S. Neman I. D. Schmitman J. C. Hadler N P. J. Iunes S. R. Paulo S. Guedes 《Radiation measurements》2001,34(1-6):145-148
In this work an assembly for indoor 222Rn measurement is presented. This assembly is made up of two acrylic plates (14 cm×14 cm) separated by a distance of 4 mm. To prevent radon daughters from outside entering the assembly (and produce alpha particle tracks striking the CR-39 detector placed in the central region of one of these plates), the borders of these plates were progressively closed, leaving open only a rectangular aperture of 5 mm×4 mm. The size of this opening was determined experimentally, by exposing in two indoor environments assemblies with different apertures as follows: (i) all borders open; (ii) two borders closed; (iii) three borders closed; (iv) four borders closed but one containing a 6 cm×4 mm opening; (v) four borders closed but one containing a 2.5 cm×4 mm opening and (vi) four borders closed but one containing a 0.5 cm×4 mm opening. Track density shows a noticeable decrease between assembly (i) and assembly (iii), remaining constant for smaller openings. Only 222Rn, a noble gas, should enter the assembly independently of the opening size. 相似文献
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Arnaud METSUE Taku TSUCHIYA 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2013,89(1):51-58
We investigate the shear response of possible slip systems activated in pure and Fe-bearing MgSiO3 post-perovskite (PPv) through ab initio generalized stacking fault (GSF) energy calculations. Here we show that the [100](001) slip system has the easiest response to plastic shear among ten possible slip systems investigated. Incorporation of Fe2+ decreases the strength of all slip systems but does not change the plastic anisotropy style. Therefore, pure and Fe-bearing MgSiO3 PPv should demonstrate similar LPO patterns with a strong signature of the [100](001) slip system. An aggregate with this deformation texture is expected to produce a VSH > VSV type polarization anisotropy, being consistent with seismological observations. 相似文献
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Application of real space Kerker method in simulating gate-all-around nanowire transistors with realistic discrete dopants 下载免费PDF全文
We adopt a self-consistent real space Kerker method to prevent the divergence from charge sloshing in the simulating transistors with realistic discrete dopants in the source and drain regions. The method achieves efficient convergence by avoiding unrealistic long range charge sloshing but keeping effects from short range charge sloshing. Numerical results show that discrete dopants in the source and drain regions could have a bigger influence on the electrical variability than the usual continuous doping without considering charge sloshing. Few discrete dopants and the narrow geometry create a situation with short range Coulomb screening and oscillations of charge density in real space. The dopants induced quasilocalized defect modes in the source region experience short range oscillations in order to reach the drain end of the device.The charging of the defect modes and the oscillations of the charge density are identified by the simulation of the electron density. 相似文献
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S Ramezani Akbarabadi H Rahimpour Soleimani M Bagheri Tagani Z Golsanamlou 《中国物理 B》2017,26(2):27303-027303
Thermal and electron transport through organic molecules attached to three-dimensional gold electrodes in two different configurations, namely para and meta with thiol-terminated junctions is studied theoretically in the linear response regime using Green's function formalism. We used thiol-terminated(–SH bond) benzene units and found a positive thermopower because the highest occupied molecular orbital(HOMO) is near the Fermi energy level. We investigated the influence of molecular length and molecular junction geometry on the thermoelectric properties. Our results show that the thermoelectric properties are highly sensitive to the coupling geometry and the molecular length. In addition, we observed that the interference effects and increasing molecular length can increase the thermoelectric efficiency of device in a specific configuration. 相似文献
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A Ahmadi Fouladi 《中国物理 B》2017,26(4):47304-047304
In this work,the electronic transport properties of Z-shaped silicene nanoribbon(ZsSiNR) structure are investigated.The calculations are based on the tight-binding model and Green's function method in Landauer-Biittiker formalism,in which the electronic density of states(DOS),transmission probability,and current-voltage characteristics of the system are calculated,numerically.It is shown that the geometry of the ZsSiNR structure can play an important role to control the electron transport through the system.It is observed that the intensity of electron localization at the edges of the ZsSiNR decreases with the increase of the spin-orbit interaction(SOI) strength.Also,the semiconductor to metallic transition occurs by increasing the SOI strength.The present theoretical results may be useful to design silicene-based devices in nanoelectronics. 相似文献
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In this paper, we present the fractional Hamilton's canonical equations and the fractional non-Noether symmetry of Hamilton systems by the conformable fractional derivative. Firstly, the exchanging relationship between isochronous variation and fractional derivatives, and the fractional Hamilton principle of the system under this fractional derivative are proposed. Secondly, the fractional Hamilton's canonical equations of Hamilton systems based on the Hamilton principle are established. Thirdly, the fractional non-Noether symmetries, non-Noether theorem and non-Noether conserved quantities for the Hamilton systems with the conformable fractional derivatives are obtained. Finally, an example is given to illustrate the results. 相似文献