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21.
聚变等离子体中的快离子压强 总被引:2,自引:2,他引:0
本文运用Fokker-Planck方程的慢化近似,考虑存在多种离子成份(包括杂质),假定它们具有共同的温度,我们得到了聚变产生的快离子压强的简单封闭形式表示式。表明在典型的工作温度下(~60keV),D-~3He等离子体中聚变产生的快离子压强约为本底热压强的20%,这与D-T等离子体工作在20keV时的比值几乎相同。因此,D-~3He和D-T在它们相应的预期工作温度下,它们各自的快离子压强对总压强的影响是类似的,然而在更高的温度下,这个比值将变得更大。 相似文献
22.
设{u_k}_k≥0为一个线性递归序列.序列{u_k(mod q)}_(k≥0)是周期的,很多人都对其周期有过研究.本文应用二次数域中理想的理论,较完全地刻面了二次线性递归序列模q的周期长度,所获结果加强并推广了Engstrom及Wall的结论. 相似文献
23.
Crystal-Orientation Dependent Evolution of Edge Dislocations from a Void in Single Crystal Cu 下载免费PDF全文
The micro-void growth by dislocation emission under tensile loading is explored with focus on the influence of crystal orientations. Based on the elastic theory, a dislocation emission criterion is formulated. It is predicted that the preferential location of dislocation nucleation and its threshold stress are dependent on the crystal orientation. Large-scale molecular dynamics (MD) simulations are also performed for single crystal copper to illustrate the dislocation evolution pattern associated with a nano-void growth. The results are in line with those given by the theoretical prediction. As revealed by MD simulations, the characteristics of void growth at micro-scale depend greatly on the crystal-orientation. 相似文献
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25.
Flat-top interleavers with chromatic dispersion compensator based on phase dispersive free space Mach-Zehnder interferometer 总被引:2,自引:0,他引:2
In this paper, novel interleavers using circular cavities (CC) in a Mach-Zehnder interferometer (MZI) has been presented and demonstrated for the first time, in which CCs act as phase dispersive mirrors which exhibit a periodic dependence on the frequency of light. Three implementation schemes have been proposed and investigated. Theoretical analysis shows the spectral characteristics of each scheme in a 50-GHz channel spacing application. Furthermore, the chromatic dispersion (CD) of each output comb can be flattened within passband by appending an additional CC. The result shows that the proposed designs with novel interferometer technique can simultaneously provide flat top passbands, high isolation stopband and low CD value as well. 相似文献
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27.
We propose a new lens scheme to focus cold atoms by using a controllable inhomogeneous magnetic field from a square current-carrying wire fabricated on a chip. The spatial distributions of the magnetic field are calculated, and the results show that the generated magnetic field is a two-dimensional (2D) quadrupole one and can be used to focus cold atoms or a cold atomic beam. The dynamic processes of cold atoms passing through our square wire layout and its focusing properties are studied by using Monte Carlo simulations. Our study shows that the atomic clouds can be focused effectively by our magnetic lens scheme, and the focal length of the atomic lens and its radius of focused spot can be continuously changed by adjusting the current in the wires. 相似文献
28.
利用现代教育理论,结合物理实验的教学实际,探讨和研究了探索性物理实验的双重教育功能.通过具体的探索性物理实验案例,验证了探索性物理实验具有激发学生的兴趣、发展学生的探索精神和唤起教师创造性的双重教育功能. 相似文献
29.
Qi Sheng Liu Lian Dong Liu Jing Min Shi 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(1):m58-m60
In the title centrosymmetric binuclear complex, [Cd2(C17H11N3O)4(H2O)2](ClO4)4, the CdII ion assumes a distorted octahedral geometry. There are π–π stacking interactions between the pyridine and 1,10‐phenanthroline ring systems of adjacent ligands at the same CdII centre. Intermolecular hydrogen bonds between the coordinated aqua ligand and the O atom of a keto group connect adjacent complex cations into extended chains. Hydrogen bonds also exist between the complex cations and the perchlorate anions. Compared with the fluorescence spectrum of the organic ligand, the complex displays strong fluorescent emission and an ipsochromic shift of the emission peaks, which may be attributed to the structural character. 相似文献
30.
Three mechanisms to reduce threading dislocations(TDs) in GaN films as the epitaxial films grow thicker are suggested by SEM and TEM 相似文献