Anisotropic Inhomogeneous Riemann S-Ellipsoids in Spheroidal Halos. I.

The classical Riemann S-ellipsoids are generalized to account for a Ferrers inhomogeneity in the mass distribution, a three-dimensional anisotropy of the velocity dispersions, and the gravitation of a spheroidal halo. The Ferrers inhomogeneity does not affect the equilibrium and stability conditions for the ellipsoids, but only changes the numerical coefficients in the equilibrium parameters. The anisotropy of the velocity dispersions changes both the equilibrium conditions and the criterion for stability of the ellipsoids, either extending or limiting the region in which the ellipsoids exist. A halo extends this region in all cases and stabilizes the ellipsoids. The observed of the velocity dispersions of stars in the neighborhood of the sun are obtained using the inhomgeneous model. __________ Translated from Astrofizika, Vol. 48, No. 4, pp. 613–632 (November 2005).     

电力系统元件非线性微分-代数子系统模型的逆系统控制:一种新算法

针对电力系统元件非线性微分-代数子系统模型,本文提出一种新算法研究其逆系统控制问题.所提出的新算法不需要对控制输出及其高阶导数做复杂的变换,具有更好的应用性.本文的逆系统控制方法主要分为两步：第1步,利用所提出的新算法来判断被控元件的可逆性,若可逆,则基于状态反馈与动态补偿,构造出元件的α阶积分右逆系统,实现复合系统的线性化和解耦;第2步,利用线性控制的理论和方法设计闭环控制器,使得元件被控对象满足期望的性能指标.最后按照本文所提出的方法,研究了多机电力系统的分散非线性汽门控制问题.仿真结果验证了本文所提方法的有效性.     

亚洲夏季风各子系统主要变率相互关系初析

使用NCEP/NCAR再分析资料和CMAP月平均降水资料分析了亚洲夏季风各个子系统的相互关系。结果表明亚洲夏季风子系统之间存在显著相关。从同期强度变化可知,当东亚季风偏强时,大尺度亚洲季风、东南亚季风、南亚季风均偏弱,相关区域降水偏少;而同时大尺度亚洲季风偏强时,东南亚和南亚季风偏强,相关区域降水偏多;东南亚季风偏强时,南亚季风偏弱,南亚地区降水偏少;反之亦然。从不同周期强度变化可知各个子系统相关仍然显著。      

Differentiating Between Subsystems and Typologies in the Analysis of Migration Regions: A U.S. Example*

Studies of migration regions are characterized by two separate conceptual approaches. The first views migration regions as clusters of highly interconnected spatial units (subsystems) while the other defines them as groups of spatial units with a similar geographic structure of flows (typologies). This paper highlights the theoretical and methodological distinctions between migration subsystems and typologies. An empirical analysis using U.S. migration data for 1940, 1960, and 1980 shows that although migration subsystems and typologies have both changed over time, each reveals a different dynamic of regional change and has different morphological characteristics.     

铜陵Cu-Au(Ag)成矿区岩浆-流体-成矿系统和亚系统的识别

文章讨论了铜陵Cu-Au(Ag）成矿区岩浆-流体-成矿系统和亚系统的识别标志，划分出9个亚系统，其中的5个为已知的中型以上矿床的分布地段，4个为该文预测的可能找到中型以上矿床的亚系统。在此基础上概略地识别出8个长江中下游铜陵铁成矿带的岩浆-流体-成矿系统，提出火成岩构造组合的类型和性质制约矿床（田）内优势矿种的发育，壳镀岩浆房和壳内岩浆房分别控制系统和亚系统的形成及其分布，提出对系统、亚系统进一步研究的建议：识别、结构、成因、定位、预测。     

THE ANALYSIS OF THE RELATIONSHIP BETWEEN THE SUBSYSTEMS OF THE ASIAN SUMMER MONSOON

In this study, the relationship between the subsystems of Asian summer monsoon is analyzed using U.S. National Centers for Environmental Protection/National Center for Atmospheric Research reanalysis and Climate Prediction Center Merged Analysis of Precipitation monthly mean precipitation data. The results showed that there is significant correlation between the subsystems of Asian summer monsoon. The changes of intensity over the same period show that weak large-scale Asian monsoon, Southeast Asia monsoon and South Asian monsoon are associated with strong East Asian monsoon and decreasing rainfall in related areas. And when the large-scale Asian monsoon is strong, Southeast Asia and South Asia monsoons will be strong and precipitation will increase. While the Southeast Asia monsoon is strong, the South Asia monsoon is weak and the rainfall of South Asia is decreasing, and vice versa. The various subsystems are significantly correlated for all periods of intensity changes.     

河南省地域旅游系统分析

文章以地域旅游系统理论为基础,对河南省地域旅游系统进行初步的分析研究,旨在为以后河南省旅游产业可持续发展提供基本背景认识;同时,也为分析其它不同地域旅游产业发展提供一种研究途径。     

Stars of extragalactic origin in the solar neighborhood

For 77 main-sequence F–G stars in the solar neighborhood with published iron, magnesium, and europium abundances determined from high-dispersion spectra and with the ages estimated from theoretical isochrones, we calculated the spatial velocities using Hipparcos data and the Galactic orbital elements. A comparison with the orbital elements of the globular clusters that are known to have been accreted by our Galaxy in the past reveals stars of extragalactic origin. We show that the abundance ratios of r-and α-elements in all the accreted stars differ sharply from those in the stars that are genetically associated with the Galaxy. According to current theoretical models, europium is produced mainly in low-mass type-II supernovae (SNe II), while magnesium is synthesized in large quantities in high-mass SN II progenitors. Since all the old accreted stars of our sample exhibit a significant Eu overabundance relative to Mg, we conclude that the maximum masses of the SN II progenitors outside the Galaxy were much lower than those inside it. On the other hand, only a small number of young accreted stars exhibit low negative ratios [Eu/Mg]<0. This can be explained by the delay of primordial star formation and the explosions of high-mass SNe II in a relatively small part of extragalactic space. We provide evidence that the interstellar medium was weakly mixed at the early evolutionary stages of the Galaxy formed from a single protogalactic cloud, and that the maximum mass of the SN II progenitors increased in it with time simultaneously with the increase in mean metallicity.     

基于神经网络方法的不确定非线性微分-代数子系统的鲁棒反推镇定控制

对于指数1且关联可测的不确定非线性微分-代数子系统,将反推方法和神经网络相结合,研究了其鲁棒渐近镇定控制问题.基于反推方法来构造镇定控制器,利用3层的神经网络来逼近每一步控制器构造过程中的不确定项.提出一种新的自适应算法对神经网络权值进行在线调节,并适当选取每一步虚拟控制器的参数,最终得到的控制器使得闭环系统是渐近稳定的.     

He,C, N,and O abundances in an ensemble of galactic planetary nebulae

The He, C, N, and O abundances in more than 120 planetary nebulae (PNe) of our Galaxy and the Magellanic Clouds have been redetermined by analyzing new PNe observations. The characteristics of PNe obtained by modeling their spectra have been used to compile a new catalog of parameters for Galactic and extragalactic PNe, which is accessible at http://www.astro.spbu.ru/staff/afk/GalChemEvol.html. The errors in the parameters of PNe and their elemental abundances related to inaccuracies in the observational data have been analyzed. The He abundance is determined with an accuracy of 0.06 dex, while the errors in the C, N, and O abundances are 0.1–0.2 dex. Taking into account the inaccuracies in the corrections for the ionization stages of the elements whose lines are absent in the PNe spectra increases the errors in the He abundance to 0.1 dex and in the C, N, and O abundances to 0.2–0.3 dex. The elemental abundances in PNe of various Galactic subsystems and the Magellanic Clouds have been analyzed. This analysis suggests that the Galactic bulge objects are similar to type II PNe in Peimbert’s classification, whose progenitor stars belong to the thin-disk population with ages of at least 4–6 Gyr. A similarity between the elemental abundances in PNe of the Magellanic Clouds and the Galactic halo has been established.