INITIALIZATION METHODS FOR GROUP TRACKING

ＩＮＩＴＩＡＬＩＺＡＴＩＯＮＭＥＴＨＯＤＳＦＯＲＧＲＯＵＰＴＲＡＣＫＩＮＧＹａｎｇＣｈｅｕｇｙａｎｇ；ＱｕＪｉａｎｍｉｎｇ；ＭａｏＳｈｉｙｉ（ＢｅｉｊｉｎｇＵｎｉｖｅｒｓｉｔｙｏｆＡｅｒｏｎａｕｔｉｃｓａｎｄＡｓｔｒｏｎａｕｔｉｃｓ，Ｂｅｉｊｎｇ，Ｃ...     

有限局部环上酉群的Sylow子群

设K=Fq2,其特征为p,q=pα,K有对合自同构:ωa|→aq,G是一个p-群,其阶为p,β群代数R=KG为一局部环。本文给出了R=KG上酉群U2nR的Sylow子群,若charK=p,U2nR的Sylow p-子群同构于某些特殊形式的矩阵生成的子群;若charK=p≠l,U2nR的Sylow l-子群同构于一循环群或半二面体群与若干Zl型循环群的圈积。     

由Ω子群所决定的格序群的结构

设Ｇ是一个格序群，П（Ｇ），П（ｍ（Ｇ），Ｐ（Ｇ），Ｃ（Ｇ）分别是Ｇ的素子群，极小素子群，极子群，凸１－子群集合，Ω（Ｇ）是Ｐ（Ｇ）在Ｃ（Ｇ）中生成的闭子格。Ω（Ｇ）的元素称为Ｇ的Ω－子群。     

对双基地雷达的间歇采样转发干扰效果分析

针对采用线性调频信号的双基地雷达,推导了间歇采样转发干扰数学模型.详细分析了干扰过程中雷达距离分辨力变化的影响,以及对干扰机的功率需求.仿真结果表明,间歇采样转发干扰可以产生前移的假目标,其前移距离远大于双基地雷达接收视线上的距离分辨力;通过选择合适的干扰功率,可以使得假目标幅度不小于真实目标幅度,达到有效的前移假目标...     

关于Grothendieck代数的特征标

本文用群表示理论和复向量理论证明了Grothendieck代数的一些性质,特别是关于Grothendieck代数基的描述,即设B为K_G(X)的基,Θ={(θ,ρ)|θ是G在X上的轨道,ρ是G_x的一个不可约表示,x∈θ},其中G_x={g∈G|gx=x},则存在1—1对应f:B→Θ使得对于任意V∈B,f(v)=(θ,ρ):V_y≠0<==>y∈θ,且ρ是G_x在V_x上的一个不可约表示,x∈θ,利用这一性质,本文给出了一个求Grothendieck代数的特征标的方法,从而改进了由Luszrig,G.在文[1]中提出的方法,并且给出二面体群D_n关于其一些子群H的Grotheodieck代数的特征标表。     

Tilts and polarity separation in the sunspot groups and active regions at the ascending and descending phases of the cycle 23

The Solar Feature Catalogues for sunspots and active regions measured with SOHO/MDI instrument and Ca II K3 spectroheliograph of the Paris-Meudon Observatory are analyzed with the automated classification technique for sunspot groups and active region polarities. We report the first classification results for daily variations of tilt angles (normal and trigonometric ones) in sunspot groups (SG) and active (AR) regions in the cycle 23. The average normal tilts are presented for every year at the ascending and descending phases of the cycle 23 which are similar to those deduced by other authors for the cycles 19–22. The normal tilts of both the sunspot groups and active regions are shown to increase in the ascending phase and a decrease in the descending phase. Similar to SG and AR areas, the trigonometric tilts are shown to have the noticeable North–South asymmetry with the Southern hemisphere dominant in the selected ascending and descending periods. The normal tilt variations with latitude follow Joy’s law revealing a periodicity along the meridian of about 10° and reaching the maximum of 14° at the latitude of about 32° corresponding to the top of the ‘royal zone’ where the sunspots appear. The variations of polarity separation with a latitude are in an anti-phase with those of the tilts reaching a maximum at the latitude of 35° and showing a small positive separation for the groups/active regions in a vicinity of the average tilts ±40°. The ratio R of the polarity separation to the trigonometric tilt fits the linear function of a latitude φ as R = −0.0213φ − 0.1245 confirming positive separation for the polarities of active regions with the average tilts, or the dominance of activity in the Southern hemisphere activity, for the selected period of observations.     

磁空间群PC 63/mmc的C-G系数计算

在晶体拉曼散射的张量计算中，晶体磁空间群的C-G系数具有重要的作用。利用本征函数法计算了Pc63／mmc磁空间群第一布里渊区中的对称点A之间的C-G系数。     

企业集团系统模式研究

采用系统理论和系统分析的方法,对企业集团系统的基本概念、基本特征和基本类型进行了系统综述与分析。     

－类非线性微分方程解空间显易结构的唯一性

对所有形如的方程的集合Ｅ（Ｄ），引入线性变换群Ｇ（Ｄ），从而将Ｅ（Ｄ）进行等价分类，并由此提出解空间显易结构唯一性概念，指出Ｂｅｒｎｏｕｌｌｉ类方程具第一显易结构，但其显易结构不唯一，而任何非Ｂｅｒｎｏｕｌｌｉ类方程着具显易结构，则其显易结构必唯一．     

Dark matter in very poor galaxy groups

We have analyzed a sample of 7000 galaxies in the Local Supercluster (LS) (V < 3100 km/s) selected from the LEDA database [Makarov, D.I., Karachentsev, I.D. A new catalogue of multiple galaxies in the local supercluster small galaxy groups. Small Galaxy Groups ASP Confer. Ser. 209, 40–46, 2000]. We have derived physical properties of poor LS groups selected by dynamical and 3D-Voronoi tessellation methods. Median values of mass-to-luminosity ratios for poor LS groups selected by these methods are 50 M_⊙/L_⊙ and 34 M_⊙/L_⊙, respectively. Physical parameters of LS galaxy triplets in comparison with other samples were evaluated. We suggest that the Dressler effect is present even in such poor groups as galaxy triplets. The data suggest that dark matter haloes are associated with the individual galaxies for LS triplets, which we find are dynamically younger systems. This contrasts with the properties of the Interacting and Northern & Southern triplet samples. For these two samples, the data suggest that the dark matter resides in a common halo. The median values of the mass-to-luminosity ratios for LS triplets, Northern & Southern triplets, and Interacting triplets are 35 M_⊙/L_⊙, 47 M_⊙/L_⊙, and 13 M_⊙/L_⊙, respectively.