排序方式: 共有101条查询结果,搜索用时 31 毫秒
91.
磁性斯格明子是拓扑稳定的自旋结构,它的尺寸小,驱动电流阈值小,被广泛认为是下一代磁性存储的基本单元.斯格明子的主要优势在于它奇特的动力学性质,特别是它能够与传导电子相互作用,在低电流密度驱动下可以在赛道上稳定地运动.本文结合磁性斯格明子赛道存储的最新研究成果,对斯格明子在赛道上的写入、驱动和读出三个方面进行了较为详细的综述.重点介绍了注入自旋极化电流这一最常见的驱动方法,分析了斯格明子在赛道上的堵塞和湮没现象,探讨了斯格明子霍尔效应及其可能造成信号丢失的危害和相关的解决方法,并在此基础上详细介绍了几种斯格明子塞道存储的优化设计方案.最后总结了磁性斯格明子赛道存储面临的一些挑战. 相似文献
92.
用密度调制的方法研究了等离子体中粒子输运问题。采用了注入脉冲式补充送气和超声分子束两种不同的密度调制方法。在HL-2A装置常规欧姆放电的情况下,运用有限差分法和Nagashima矩阵技术,求解了粒子平衡方程。计算出了粒子的输运系数(对流速度v和扩散系数D)。研究了粒子输运系数与等离子体线平均密度之间的关系。实验结果表明,在欧姆放电的情况下,等离子体芯部的粒子对流速度方向始终是向内的,并且密度低时,粒子输运系数(粒子扩散系数D和对流速度v)较大;密度高时,粒子输运系数较小。 相似文献
93.
Study of runaway electron behaviour during electron cyclotron resonance heating in the HL-2A Tokamak
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During the current flat-top phase of electron cyclotron
resonance heating discharges in the HL-2A Tokamak, the behaviour of
runaway electrons has been studied by means of hard x-ray detectors
and neutron diagnostics. During electron cyclotron resonance
heating, it can be found that both hard x-ray radiation intensity
and neutron emission flux fall rapidly to a very low level, which
suggests that runaway electrons have been suppressed by electron
cyclotron resonance heating. From the set of discharges studied in
the present experiments, it has also been observed that the
efficiency of runaway suppression by electron cyclotron resonance
heating was apparently affected by two factors: electron cyclotron
resonance heating power and duration. These results have been
analysed by using a test particle model. The decrease of the
toroidal electric field due to electron cyclotron resonance heating
results in a rapid fall in the runaway electron energy that may lead
to a suppression of runaway electrons. During electron cyclotron
resonance heating with different powers and durations, the runaway
electrons will experience different slowing down processes. These
different decay processes are the major cause for influencing the
efficiency of runaway suppression. This result is related to the
safe operation of the Tokamak and may bring an effective control of
runaway electrons. 相似文献
94.
Density fluctuations were first measured in the core region of HL-2A tokamak plasma using a newly developed multi-channel FIR interferometer system. In divertor ohmic discharges, we measured the radial density fluctuation levels of 5%, which increase to 10-20% during the appearance of MHD activity. Most of the power density in the density fluctuation spectrum is directly associated with m = 2 tearing modes. The fluctuation levels reduce to 1/3 and plasma confinement is improved during off-axis electron-cyclotron-resonance heating (ECRH). 相似文献
95.
描述了钕玻璃激光汤姆逊散射系统在HL 1M装置上的光路总体布局与调试 ,及HL 1M装置上电子温度的测量。散射光源为带有一级放大并可产生 1或 8个激光脉冲的钕玻璃激光器 ,用非线性KDP晶体倍频后 ,能够产生波长为 5 30nm、输出功率约为 10 0MW的脉冲。采用大孔径接收光路和D f =1 2 .8光栅光电谱仪 ,能够实现对等离子体五个空间点电子温度的测量。线色散约为 4 2nm·mm- 1 ,温度的测量范围为 10 0eV~ 2keV。 相似文献
96.
97.
A chiral 3D metal-organic framework [CdL]·DMSO·H2O(1) was constructed by an N-methyl substituted salan ligand(H2L), and characterized by elemental analyses, IR, TGA, powder XRD and single-crystal X-ray crystallography. 1 crystallizes in the chiral hexagonal space group P6522 with a = b = 12.2175(3), c = 51.450(3) , V = 6650.9(4) 3, Z = 6, Mr = 883.45, Dc = 1.323 g·cm–3, F(000) = 2760, λ(CuKα) = 1.54178 , μ = 4.771 mm–1, GOOF = 1.041, R = 0.0313 for 3901 observed reflections with I 2σ(I) and wR = 0.0773. 1 consists of three identical sets of independent 3D frameworks interpenetrated with each other. In each set of such 3D frameworks, one half of the monomer(CdL)1/2 as the building unit forms double antiparrel helical chains which are further bridged together by other(CdL)1/2 units from adjacent helical chains. All CdL units in 1 adopt Δ geometry. DMSO and water guest molecules are found in the gap of the interpenetrated frameworks. 相似文献
98.
决策者用语言变量评价目标权系数和定性目标,对定量目标进行无量纲化处理,并统一表示成不规则四边形模糊数的形式.经集结确定各决策对各方案的模糊评价指标,然后用乐观系数准则确定各决策对各方案的排序指标.最后用平均值法集结所有决策者对各方案的排序指标,并确定出群体对各方案的排序. 相似文献
99.
研究了具有常规故障的四个部件冗余可修复系统模型.将一组微分-积分方程描述的模型转化为六维空间的积分方程形式.运用算子理论,证明了此系统非负解的存在唯一性.并且研究了以范数为指标衡量控制标量为标准的最优控制问题. 相似文献
100.