二价离子掺杂钨酸铅晶体的计算机模拟

应用GULP软件计算了PbWO4(PWO)晶体中分别掺杂Zn、Ca二价离子的相关缺陷生成能,并对计算结果进行了讨论.结果表明,Zn离子进入PWO晶体中只能占据铅空位附近的填隙位置,而Ca离子进入PWO晶体中可以占据铅空位,也可以占据铅空位附近的填隙位置,这两种情况出现几率近似;对于相同的掺杂浓度,在掺Zn的PWO晶体中的孤立铅空位数量比掺Ca的PWO晶体中少,从而掺Zn可以更好地抑制与铅空位有关的短波段吸收,增加晶体的光产额.     

层状大地视真频参数测深曲线的反演

在Cole-Cole模型假设的基础上,用一种新的递推反演算法对无电磁偶合影响时的水平层状大地对称四极装王复电阻率测深曲线进行反演,得出了层状大地上视电阻率、视时间常数、视频率相关系数、视充电率的视真频参数测深曲线.与需要复电阻率频谱的反演方法不同,该递推算法只需要4个不同频率的复电阻率数据,大大减少了野外工作量.通过对几种层状介质模型反演计算,结果表明:视真频参数测深曲线能够反映出各地层介质的真频参数随深度的变化规律;综合利用视真频参数能确定层状介质的频谱特性,从而达到区分岩石性质的目的.     

Detection of the translational oscillations of the Earth''''s solid inner core based on the international superconducting gravimeter observations

Before about 100 years, the layered structures of the Earths body and the existence of the liquid core had been found, then the solid inner core and detailed structures in the interior of the Earth are demonstrated, it proves that the satisfied achievements had been obtained in recogni-tion of the Earths interior structures. In recent years, with the increasing requirements of the basic sciences and space techniques to geodynamics of the Earths interior, the theoretical study and practical de…     

钙离子体系中显式阵发振荡随机共振

采用介观的化学朗之万方程研究了内噪音对于钙离子阵发振荡行为的影响.模拟结果显示,体系的信噪比值在某一内噪音强度下,即某一细胞体积下达到最大.这一行为与随机共振现象相似,称之为显式阵发振荡随机共振.若采用相关时间度量阵发振荡的相关性,则阵发振荡的相关时间也会在某一细胞体积下达到最大.     

泛函微分方程解的渐近性态

研究下面一类高阶非线性泛函微分方程解的渐近性态[q(t)x(2n-1)(t)]′ p(t)f[x(σ(t))]=e(t).建立了方程解强迫振动的充分条件.这些结果扩展了文献[1]f(x)的范围.     

基于Hilbert-Huang变换理论的非线性系统分析

介绍了Hilbert-Huang变换(HHT)这一全新的处理非线性、非平稳信号数据的方法,将其用于分析典型的非线性系统-Duffing方程,通过对使用三阶Runge-Kutta法求解而得到的Duffing方程数值解分解后,得到了4个固有模态函数分量和1个残余量,给出了相应的能量-频率-时间分布图-Hilbert谱,并将其边际谱与Fourier谱作了比较。结果表明,此方法具有更好的局部特性分辨以及瞬时频率分解效果,经HHT变换得到的主要固有模态函数分量具有明确的物理意义,体现在Hilbert谱上的系统固有频率存在明显的波内调制机制,分析结果充分保留了系统的非线性特征。     

Intrinsic abnormal electromagnetic medium based on polar lattice vibration

A new class of media with abnormal electromagnetic parameters has been attracting increasing attention because of its exotic properties and potential application. Currently, typical metamaterials are mainly composed of artificially designed metallic periodic structures. However, due to the limitations of available fabrication technologies, physical size and material effects, it is difficult to realize these abnormal properties by these artificial structures in the high-frequency regime. Therefore, it is important to find materials with intrinsic abnormal electromagnetic responses. In this field, a new mechanism based on the interaction between polar lattice vibrations and electromagnetic waves has been proposed. In this paper, we review progress in this field.     

一类多种天敌种群和害虫种群相互作用的稳定性

本文论述两种天敌种群和两种害虫种群的数学模型的正平衡点的稳定性,并把结果推广到n种天敌种群和n种害虫种群的情形。     

—阶中立型时滞微分方程的振动性──祝贺肖伊莘教授八十寿辰

本文给出一类中立型微分方程振动的新的充分条件。     

Kolmogorov生态系统的浑沌现象

本文在Kolmogorov生态系统的基础上,研究当b_(12)≠0,c_(12)≠1,且内禀增长率为r_1=f+ε(λ_1+λ_2cosωt)r_2=f+ε(λ_1+λ_2cosωt)受到ελ_3cosωt的强迫激励时所产生的浑沌现象。