相对论性非磁化等离激元色散关系的数值解

对处于相对论性振荡的无磁化等离子体中的纵、横等离激元色散方程进行数值求解,得到比较全面的色散关系图像.在极端相对论情况下,我们的数值计算结果与解吸结果吻合.同时,将我们的计算范围扩展到适中相对论温度以及弱相对论温度,得到完全相对论性无磁化等离子体色散关系图像.最后,根据等离子体的色散特性,对不同温度下的色散曲线进行数值拟合,得到了色散关系数值解.     

新型微带环慢波结构的研究

提出了一种新型微带慢波结构:微带环结构,对其高频特性进行了研究,采用微米量级的结构尺寸,将带宽拓展到毫米波段。通过利用电磁场仿真软件HFSS对该结构进行模拟计算,得到了各个结构参数下慢波电路的色散特性和耦合阻抗,分析了结构参数对其高频特性的影响。对微带环加杆结构的情况也进行了分析。得到对高频特性影响较大的结构参数,能够为器件的进一步研究提供指导参考。     

Influence of water saturation on propagation of elastic waves in transversely isotropic nearly saturated soil

Biot's two-phase theory for fluid-saturated porous media was applied in a study carried out to investigate the influence of water saturation on propagation of elastic wave in transversely isotropic nearly saturated soil. The characteristic equations for wave propagation were derived and solved analytically. The results showed that there are four waves: the first and second quasi-longitudinal waves (QP1 and QP2), the quasi-transverse wave (QSV) and the anti-plane transverse wave (SH). Numerical results are given to illustrate the influence of saturation on the velocity, dispersion and attenuation of the four body waves. Some typical numerical results are discussed and plotted. The results can be meaningful for soil dynamics and earthquake engineering.     

偏振模色散对光孤子传输系统的影响

从考虑偏振模色散的光孤子的非线性薛定谔方程角度出发,用分步傅立叶方法对非线性耦合薛定谔方程进行求解。研究了偏振模色散效应对于光孤子传输系统的影响:首先在单个孤子脉冲的情况下,讨论了光孤子的自俘获效应对于偏振模色散的自适应能力,进而考虑更有意义的脉冲序列的情况,即因PMD引起的两个光孤子之间的相互作用以及能量损失而带来的系统损耗的问题。     

Use of probabilistic and deterministic measures to identify unfavorable earthquake records

This study introduces measures to identify resonant （concentration of energy in a single or a few frequencies） or unfavorable earthquake ground motions. Probabilistic measures based on the entropy rate and the geometric properties of the power spectral density function （PSDF） of the ground acceleration are developed first. Subsequently, deterministic measures for the frequency content of the ground acceleration are also developed. These measures are then used for identifying resonance and criticality in stochastic earthquake models and 110 acceleration records measured at rock, stiff, medium and soft soil sites. The unfavorable earthquake record for a given structure is defined as the record having a narrow frequency content and dominant frequency close to the structure fundamental natural frequency. Accordingly, the measures developed in this study may provide a basis for selecting records that are capable of producing the highest structural response. Numerical verifications are provided on damage caused to structures by identified resonant records.     

双频雷达高度计电离层色散效应误差分析

由于现代星载雷达高度计采用了脉冲压缩技术,引入了电离层色散误差,在双频高度计的低频段该误差更明显。本文基于全去斜技术的理论模型,推导了这项误差的机理,提出可以把该误差等效为二次相位误差,并结合具体参数给出了分析的结果。本文还讨论了Chirp信号的多普勒误差对测高的影响。最后,作者通过计算机仿真得到了电离层色散效应对系统点目标响应的影响,对前面的结论进行了验证。     

Pr^3＋：LaF3晶体中的电磁感应透明及其色散特性

运用密度矩阵方程,从理论上研究了Pr^3＋：LaF3晶体中λ-型三能级系统,对探测光的电磁感应透明吸收和色散特性．讨论了探测光吸收及色散与光学耦合场拉比频率强度,探测光吸收与光学耦合场失谐量之间的依赖关系．理论研究结果表明,电磁感应透明（EIT）受光学耦合场的调制,并且其中心透过效率随光学耦合场拉比频率强度的增强而增大;电磁感应透明窗口位置受光学耦合场失谐量的影响．同时,也讨论了色散随耦合光场拉比频率强度的变化规律．     

浅析GPS精密单点定位误差改正模型

本文利用误差改正模型方法,得到精密单点定位总模型,利用这个模型对多个历元数据进行解算,并与非改正结果进行了比较、分析。分析结果表明模型能够显著提高单点定位的精度。     

Application of the ISCST3 model for predicting PCDD/F concentrations in agricultural soil in the vicinity of a MSWI plant in China

Based on the Industrial Source Complex Short-Term Version 3 （ISCST3） model, a simplified modeling approach was developed to predict concentrations of congeners of polychlorinated-p-dioxins and dibenzofurans （PCDD/Fs） of agricultural soil, within a radius of 3 kin from a municipal solid waste incinerator （MSWI） plant after its 4-year operation in Hangzhou, China. Comparisons were made between the measured and estimated congener-specific concentrations and the international-toxic equivalent （I-TEQ） values of soil samples with respect to distance from the stack. The results indicate that the predictions of soil PCDD/F concentrations and K-TEQ values were generally lower than their observations, and that the higher the degree of underestimation seems, the greater the further downwind one gets. Nevertheless, most of the predictions were in good agreement with the trend of measured ones and were within a factor of ten for samples located within 1 kin of the plant. Besides, analysis of contributions of various deposition pathways confirms that in addition to wet particle deposition, the dry gaseous deposition is essential for realistic prediction of PCDD/F depositions to soil, especially for tetra- and penta-chlorinated dioxins.