电磁感应双光子带隙的产生和控制

基于电磁感应透明技术, 通过求解原子的密度矩阵方程和电磁场的传输矩阵方程, 研究了被行波场和驻波场共同耦合的一个四能级冷原子介质的稳态光学特性, 发现在特定参数下能够产生一个几乎完美的双光子带隙结构, 在这两个光子带隙对应的频率区域内反射率都均匀地超过95%. 通过改变耦合场的强度和频率, 可以方便地调节这两个光子带隙的位置和宽度. 这一双光子带隙结构可用来实现全光路由和全光开关, 有望在全光信息网络中获得应用.     

6Li费米原子气中的配对能隙

在超导体中，为了拆散一个库珀对，必须提供某种激发能，这一能量的下限即所谓能隙．超导能隙可以通过光电子能谱实验进行测量．^6Li原子其质子、中子和电子的总数是奇数q，因此属于费米原子．除非^6Li原子两两结成库珀对，它们不可能共同占据量子力学的基态，实现玻色一爱因斯坦凝聚(BEC)．     

Origin of the 420 nm Absorption Band and Effect of Doping Fluorine in PbWO4 Crystals

The electronic structures for three types of PbW04 (PWO) crystals, the perfect PWO, the PWO containing lead vacancy (PWO-Vpb) and fluorine doped PWO crystal (F^-：PWO), are systematically studied within the framework of density functional theory. The computational results show that the Pb 6s state situates below the valence band so that Pb^2 ions are unable to trap holes forming Pb^3 or Pb^4 to compensate for VPb^2-. The hole-trappers in PWO-Vpb are O^2- ions. Two of the longer-bond O^2- ions share a hole forming O2^3-, and four of the longer-bond oxygen ions trap two holes forming an associated color centre [O2^3--Vpb-O2^3-], which may be the origin of the 42Onto absorption band. It is also concluded that the doping of F^- would reduce the band gap and F^- ions substituting for O^2- can effectively restrict the formation of [O2^3--Vpb-O2^3-] and weaken the 42Onm absorption band and hence enhance the scintillation property of PWO.     

Theoretical Study on the Rotational Bands and Shape Coexistence of^179，181，183Au in the Particle-Triaxial-Rotor Model

We perform a series of theoretical calculations and investigation for nuclei 179，181，183Au in the particle-triaxialrotor model with variable moment of inertia. The calculated energy spectra in^179,181,183Au agree well with the experimental data globally. The obtained results indicate that the nuclei^179,181,183Au have prolate deformation and involve shape coexistence with different deformation parameters in different bands. The main configuration of bands 1, 2, 3 and 5 in these nuclei are identified as [541]1/2^- (πh9/2, α = 1/2), [541]1/2- (πh9/2, α= -1/2),[530] 1/2- (πf7/2) and [660] 1/2^ (πi13/2), respectively.     

A Photonic Bandgap Filter Using Metallic Hilbert Curves

We theoretically suggest that a metallic plate with Hilbert curves can possesses multiple resonances in a linear scale, leading to multiple stop bands and pass bands for electromagnetic waves over a wide frequency range.The forward transmission from a line source nearby a small plate covered by four cells with Hilbert curves is checked by a probe at the far field, the results agree well with the multiple resonance frequencies calculated by the plane wave incidence under a periodic boundary condition, the return loss spectra show that radiations of a line antenna working at 4.5 GHz can be greatly enhanced, which results from the interaction of the antenna and the subwavelength metallic plate. This kind of metallic pattern is very practical in multi-frequency functioned wave devices with sub-wavelength sizes.     

光子晶体压力传感器的基本原理

通过研究一维光子晶体受压力后其光带隙性能的变化，提出了光子晶体压力传感器的原理.计算表明，压力的大小与禁带起始波长、截止波长和禁带宽之间呈简单的线性对应关系.这就提供了通过测量光带隙性能而感知外载荷或者通过施加载荷而调制光带隙性能的可能.由于光子晶体的结构周期和光波波长为一个数量级，也就有可能制造出一系列精巧的压力、温度传感器或者其他精密仪器. 关键词： 压力传感器 光子晶体 光带隙性能     

A≈80区奇–奇核80,82Rb的晕带能谱计算

在A≈80区奇-奇核旋称反转问题上已提出几种机制,但没有一种理论推断是结论性的.在本工作中将角动量投影壳模型应用到^80,82Rb核,对组态为πg_9/2⊙νg_9/2的正宇称晕带和组态为π(p_1/2,p_3/2,f_5/2)⊙νg_9/2 的负宇称晕带理论计算和实验结果进行了比较,特别是对正宇称晕带中的signature反转机制进行了探讨.角动量投影壳模型计算显示正宇称晕带中的signature反转是原子核随自旋增加形状发生变化的信号,其间原子核从低自旋的长椭球变到高自旋的扁椭球.此外,还确定了此两带的原子核形状     

126Cs的高自旋态能级结构

利用融合蒸发反应¹¹⁶Cd(¹⁴N,4n)¹²⁶Cs布居了¹²⁶Cs的高自旋态.观测到了100多条新的γ跃迁和相应的能级,建立了双奇核¹²⁶Cs由9个转动带构成的能级纲图.尝试性地指定了大部分能级的自旋和宇称以及各转动带的Nilsson单粒子组态.极大地丰富了已有的实验结果.     

氧气分压对反应溅射制备TiO2薄膜带隙的影响

在不同的氧气分压下 ,用直流反应磁控溅射法制备了玻璃基TiO2 薄膜试样 ,测试了试样的荧光发射光谱。结果表明 ,氧气分压为 0 35和 0 6 5Pa时 ,荧光光谱在 370 ,4 72和 5 14nm处出现发射峰 ;氧气分压为 0 10和 0 15Pa时 ,发射光谱峰出现在 370和 4 90nm处。试样带隙为 3 35eV。0 35和 0 6 5Pa氧气分压下溅射的试样在带隙中有两个分别低于导带底 0 72和 0 94eV的缺陷能级 ,0 10和 0 15Pa氧气分压下溅射的试样在带隙中有一个位于导带底 0 2 3和 1 2 9eV之间的缺陷能带 ;增加氧气分压 ,缺陷能带转变成两个缺陷能级 ,在 0 6 5Pa氧气分压下 ,缺陷能级几乎消失。     

关于185Pt核多带结构的回弯机制

最近报道的¹⁸⁵Pt核多带结构的实验结果,又一次提出了其中五条带回弯现象究竟是由于h_9/2质子对转动排列所致,还是来自于i_13/2中子对转动排列结果的尖锐问题.基于阻塞效应的实验事实支持前者,而总罗斯量(转动坐标系中的总能量)而的理论计算则支持后者,本文在分析上述两种解释的前提条件的基础上,给出考虑了带交叉过程动力学效应的理论计算结果.说明了h_9/2质子对转动排列应是这五条带出现回弯的根源.