Several parameters of generalized Mycielskians

The generalized Mycielskians (also known as cones over graphs) are the natural generalization of the Mycielski graphs (which were first introduced by Mycielski in 1955). Given a graph G and any integer m?0, one can transform G into a new graph μ_m(G), the generalized Mycielskian of G. This paper investigates circular clique number, total domination number, open packing number, fractional open packing number, vertex cover number, determinant, spectrum, and biclique partition number of μ_m(G).     

A side-coupled photonic crystal filter with sidelobe suppression

This paper presents the theoretical model and the optimization method to suppress the sidelobes of side-coupled photonic crystal filters. Numerical verification shows a good agreement between the theoretical method and the finite-difference time-domain simulation, but the theoretic method does not involve the time-consuming computation. The theoretical method also presents a better physical image for choosing the critical parameters, such as the quality factor, phase shift and the number of resonators. Based on the theoretical model, two optimization methods (chirp and cascading) are proposed to deeply suppress the sidelobes. They also show more flexibility in controlling the bandwidth and steepness of the roll-off in the filter. PACS 42.70.Qs     

复杂像散椭圆光束的轨道角动量的实验研究

提出一种直接测量光束的轨道角动量的方法，其原理是把具有轨道角动量的光束照射到一个金属靶上，使其在光束的角动量作用下发生转动. 通过测量靶转动的角度来计算光束的角动量值. 对几种不同参数的光束的轨道角动量进行了测量，获得了轨道角动量与光束参数之间的关系，实验结果与理论分析较好地符合. 关键词： 复杂像散椭圆光束 轨道角动量 测量     

KNSBN晶体猫式互抽动相位共轭光特性

在KNSBN：Ce晶体中，利用二波耦合作用，在单一光束无法获得相位共轭光的条件下，实现了“猫”式互抽运相位共轭光输出，获得较高的共轭光发射率，实验结果表明，晶体的二波耦合作用可以使晶体的自抽运相位共轭光的阈值光强降低。入射光的入射角范围增大，响应时间缩短。     

哈密顿算符的对角化与能量本征值问题的代数解法

提出了将哈密顿算符对角化的一种方法.围绕一维谐振子讨论了如何将哈密顿算符对角化、引进的是玻色算符还是费米算符的问题,并分析了能量量子化的原因及能量子与声子的区别.     

脉冲磁场处理对碳纳米管掺杂MgB2线材临界电流密度的影响

对碳纳米管(CNT)掺杂MgB₂超导体磁场处理后的行为进行了研究. 结果表明，CNT掺杂MgB₂超导体经5T脉冲磁场处理后临界电流密度J_c(H)在低磁场下提高了2—3倍，高场下提高一个数量级以上，扫描电镜结果显示CNT沿着处理磁场方向规则排列并且成为MgB₂基体的形核中心和高效的磁通钉扎中心. 关键词： 2')" href="#">MgB₂ 碳纳米管 脉冲磁场处理     

High longitudinal selectivity of shifting multiplexing in volume holograms

High longitudinal selectivity of the shifting multiplexing with spherical reference wave is proposed and demonstrated. A simplified method based on wave optics is used for calculating the selectivity, and the result fits well the experimental measurement. Under the paraxial condition, a simple formula for the longitudinal selectivity is introduced. With use of an object lens with effective NA=0.817, we obtain that an FWHM of selectivity is as small as 1 μm.     

晶体学与准晶体学点群的母子群关系

依据群论，得出了准晶体学点群的直积或半直积推导算式；依据结晶学理论，绘出了五角、八角、十角和十二角晶系各点群的极赤投影图.据此推导出了每一个准晶体学点群的全部最大子群，从而推导并绘制出了三维晶体学和准晶体学点群之间的母子群关系(60个点群的“家谱”).该“家谱”以最大子群链的图解形式直观地给出了每个点群的最小母群和最大子群. 关键词： 准晶体 晶体 点群 最大子群 最小母群 群链