Models for highly flattened, rapidly rotating cool stars in a Newtonian approximation

We investigate the physical characteristics of single, rapidly rotating white dwarfs, which could form as a result of a merger of two white dwarfs with different masses and filled Roche lobes, due to the radiation of gravitational waves. When the merging of the binary components occurs without loss of mass and angular momentum, the merger products are subject to secular instability, and the density in their cores does not exceed ～10⁸ g/cm³. Models are constructed for rapidly rotating neutron stars, which could form after the collapse of rotating iron cores of evolved massive stars. Dynamically unstable neutron-star models are characterized by a shift of the maximum density from the rotational axis. The total momentum of such neutron stars is about half the maximum possible momentum for the evolved cores of massive stars.     

Axially symmetrical models of the products of a conservative merger of a binary white dwarf with similar-mass components

The possibility of a conservative merger of a binary white dwarf whose components have similar masses is studied. Axially symmetrical models for single, rapidly rotating white dwarfs that are possible products of such mergers are constructed and their physical characteristics investigated. The merger products must be turbulent, and the viscosity of the electron gas is not sufficient to support the observed luminosities of massive, bright white dwarfs. The amount of dissipative energy and the timescale for its release are estimated.     

Edge tectonics (trench rollback, terrane export) of Gondwanaland-Pangea synchronized by supercontinental heat

From 650–500 Ma assembly, 320 Ma merger in Pangea, to 185 Ma breakup, Gondwanaland developed by the accretion of lithosphere along the convergent edge on the south and by the export of terranes from the divergent edges on the west and northeast. The interior underwent epeirogenic movement except in areas affected during the merger by farfield shortening. Synchronous or near-synchronous events on the edges and interior are linked hypothetically by convection currents in the asthenosphere driven by supercontinent-induced heat. On the convergent edge, currents countered the sinking slab to roll back the trench and generate a backarc basin. On the divergent edge, currents initiated an ocean that prised off continental rims in the form of terranes. In the interior, currents extended the lithosphere in basins and rifts.     

The Simulation of Orbit Decay of Double Neutron Star System PSR J1906+0746 by the Gravitational Wave Radiation

With the discovery of the double neutron star (DNS) merger event GW170817 by LIGO, DNS systems have become one of the important candidates for gravitational wave (GW) observation. There are 19 DNS systems that have been discovered, and PSR J1906+0746 is the youngest DNS system with the age of about 0.1 Myrs. We simulate its orbital decay over its entire life by the GW radiation from the initial stage to the coalescence. For the DNS PSR J1906+0746, we obtain its initial orbital period of 3.99 hrs (3.98 hrs at present) with the nearly circular orbit, and the merger age of 3.18 × 10⁸ yr. At the last minute of coalescence, corresponding to the orbital radius change from 335 to 30 km, we present the GW frequency to be 30 and 1122 Hz, respectively. As a comparison, with the GW frequency from 45 to 450 Hz, the orbital radii of the source GW170817 correspond to 163 and 57 km, respectively.

     

Edge tectonics (trench rollback,terrane export) of Gondwanaland-Pangea synchronized by supercontinental heat

From 650–500 Ma assembly, 320 Ma merger in Pangea, to 185 Ma breakup, Gondwanaland developed by the accretion of lithosphere along the convergent edge on the south and by the export of terranes from the divergent edges on the west and northeast. The interior underwent epeirogenic movement except in areas affected during the merger by farfield shortening. Synchronous or near-synchronous events on the edges and interior are linked hypothetically by convection currents in the asthenosphere driven by supercontinent-induced heat. On the convergent edge, currents countered the sinking slab to roll back the trench and generate a backarc basin. On the divergent edge, currents initiated an ocean that prised off continental rims in the form of terranes. In the interior, currents extended the lithosphere in basins and rifts.     

Possible scenarios for the formation of Ap/Bp stars

Possible paths for the formation of Ap/Bp stars—massive main-sequence stars with strong magnetic fields—are analyzed based on modern theories for the evolution of single and binary stars. Assuming that the strong magnetic fields of these stars are the main reason for their comparatively slow axial rotation and the observed anomalies in the chemical compositions of their atmospheres, possible origins for these high magnetic fields are considered. Analysis of several possible scenarios for the formation of these stars leads to the conclusion that their surface magnetic fields are probably generated in the convective envelopes of the precursor stars. These precursors may be young, single stars with masses 1.5–3 M _⊙ that formed at the peripheries of forming star clusters and ended their accretion at the Hayashi boundary, or alternatively close binaries whose components have convective envelopes, whose merger leads to the formation of an Ap/Bp star. Arguments are presented supporting the view that the merger of close binaries is the main channel for the formation of Ap/Bp stars, and a detailed analysis of this scenario is presented. The initial major axes of the merging binary systems must be in the range 6–12 R _⊙, and the masses of their components in the range 0.7–1.5 M _⊙. When the merging components possess developed convective envelopes and fairly strong initial magnetic fields, these can generate powerful magnetic fields “inherited” by the products of the merger—Ap/Bp stars. The reason the components of the close binaries merge is a loss of angular momentum via the magnetic stellar winds of the components.     

Spatial rationalisation in multi-plant enterprisesRäumliche rationalisierung in mehrwerk-unternehmenRationalisation spatiale dans les entreprises à usines multiples

In an old established industrial area spatial rationalisation stratégies of multi-plant enterprises play an important role in modifying the location of industry. The special characteristics of the multiplant enterprise are set out, and the effects of organisational structure, socio-political environment, enterprise inter-action, and merger activity on industrial location is considered. Quantitative techniques available to management are reviewed, but it is shown there is little evidence to indicate they have been used. Three spatial rationalisation strategies are identified, each producing a different location pattern, although most multi-plant enterprises will adopt some form of strategy mix.     

Possible Electromagnetic Manifestations of Merging Black Holes

Astronomy Reports - The scenario of a merger of two black holes surrounded by an accretion disk is considered. As a result of the emission of gravitational waves, the mass of the central object...     

The Role of Gravitational Radiation in the Evolution of Stars and Galaxies

The conditions for the formation of close binaries containing main-sequence stars, degenerate dwarfs of various types, neutron stars, and black holes of various masses are considered. The paper investigates the evolution of the closest binary systems under the influence of their gravitational-wave radiation. The conditions under which the binary components can merge on a time scale shorter than the Hubble time as a result of their emission of gravitational waves are estimated. A self-consistent scenario model is used to estimate the frequency of such events in the Galaxy, their observable manifestations, the nature of the merger products, and the role of these events in the evolution of stars and galaxies. The conditions for the formation and evolution of supermassive binary black holes during collisions andmergers of galaxies in their dense clusters are studied.

     

黑龙江省两次温带气旋暴雪过程对比分析

利用多种资料对黑龙江省两次由江淮气旋和蒙古气旋合并引发的暴雪过程的水汽、热动力条件和中尺度特征进行了对比分析。结果表明：（1）两次暴雪过程都发生在北支槽和短波槽合并、北支槽北部有冷涡的背景下,850 hPa上低涡合并促使江淮气旋和蒙古气旋合并;气旋合并后,低空急流为降雪提供了充足水汽,强暖平流使气旋爆发性发展,导致降雪加强。（2）两次降雪过程都表现出逗点云系的合并发展,"1211 "暴雪过程中高层形成涡旋偏西,700 hPa低涡东部偏南风引导气旋北上西折,低空急流和地形共同作用使暖湿空气强烈辐合上升,产生对流云,暴雪发生在A类逗点云系的头部,降雪强度大,范围广;"1412"暴雪过程高空槽低涡位置偏东,700 hPa低涡东部西南风始终引导气旋向东北方向移动,近地面层具有冷垫,暴雪主要发生在B类气旋逗点云系头部西侧中低云团中,降雪范围和强度较"1211"过程小。（3）低层（0.3 km）冷空气侵入和中高层（5.5 km）转为偏北风对判断降雪开始和结束有很好的表征意义。（4）冷涡前部强高压脊使冷涡移动缓慢,从而延长了降水的持续时间,气旋移动路径与高压脊伸展方向密切相关。     

The origin of intergalactic stars in galaxy clusters

The paper analyzes possible origins of stars located in intergalactic space that are not bound to specific galaxies, which comprise 15–50% of all stars in galaxy clusters. Some such stars can form in streams of intergalactic gas flowing around gas-rich disk galaxies moving in the cluster. Others may be the products of the decay of young, low-mass, spheroidal galaxies after the loss of their gaseous components during an initial burst of star formation. The decay of low-mass disk galaxies moving at high speeds after they have lost their gaseous components due to the pressure of the incident flow of dense intergalactic gas is possible in the cluster core. The largest fraction of intergalactic stars are probably produced by the partial disruption of galaxies as a result of close passages, collisions, or mergers. Collisions of low-mass, gas-rich galaxies are especially good suppliers of intergalactic stars. Both stars from decaying stellar components of galaxies and stars arising in the gaseous components of colliding galaxies can be supplied to the intergalactic medium. The merger of galaxies harboring supermassive black holes in their nuclei could lead to the partial or total disruption of these galaxies during the deceleration of the binary black hole that is formed during the merger. An enhanced density of intergalactic stars is observed in the cores of galaxy clusters, underscoring the role of galaxy collisions in the formation of the intergalactic stellar population, since the frequency of galaxy collisions grows with their density.     

The magnetic-field structures of chemically peculiar stars

Measurements of the longitudinal magnetic field of the CP star HD 62140 with high accuracy (σ ～ 50 G) are used to construct a magnetic-dipole model for this star. The model describes the observed phase dependence of the field very well, supporting the idea that CP stars have dipolar magnetic fields. Based on an analysis of the CP stars HD 32633 and HD 142301, which were earlier suggested to have dipoles shifted perpendicular to the dipole axis, it is concluded that the only possible models in this case have one or two shifted dipoles, with the distance between the monopoles being comparable to the stellar radius. Such configurations may occur as a consequence of deformations of the field in early stages of the star’s evolution, due to the accretion of higher-mass objects or a merger with another component, as well as the influence of a convective core.     

安徽省地质灾害气象预报预警模型研究

通过对基于地质环境信息平台的地质灾害气象预报预警模型构建进行了探讨。拟在先期已具备的地质灾害预警分区、地质灾害易发分区基础上,以地质灾害"易发度"、预报降雨量、有效降雨量为因子,采用logistic回归模型确定各个评价单元的预警等级,经插值计算、图斑合并,实现地质灾害气象风险预警。     

基于GIS的DRASTIC下辽河平原地区地下水防污性评价

在运用基于GIS的DRASTIC评价方法,对下辽河平原潜水的防污性进行评价的过程中,分析了影响下辽河平原固有防污性的最主要的7个水文地质参数,分别评价各个因子.利用GIS的空间分析功能中区对区的合并分析功能,依次对各单指标分级图进行区合并操作,合并后生成区文件,绘制出防污性分布图.结果表明,防污性能较差区主要分布在下辽河平原河谷地带,面积2 993.51 km²,占全区总面积的12.78%.评价结果有利于合理利用土地,有效保护地下水资源和防止地下水污染.     

浅议国有地勘单位分类改革

国有地勘单位是我国地质找矿的主力军,深入分析国有地勘单位面临的形势、现状和问题,将有利于我国地勘行业的可持续健康发展。当前,国有地勘单位改革发展面临新的机遇,全国正积极推进事业单位分类改革,但国有地勘单位依然面临众多的历史遗留问题和分类改革过程中产生的新问题。因此建议:进一步做好国有地勘单位分类改革指导工作,建立地勘单位分类改革的激励引导与规范约束机制,研究细化地勘单位分类改革的支持政策,统筹考虑中央与属地化管理地勘单位分类改革,引导区域地勘队伍的合并重组,同时地勘单位自身要积极应对分类改革。     

Resistance to the deinstitutionalization of a region: Borders,identity and activism in a municipality merger

Regions are contested processes in which various layers of borders become articulated, deconstructed and reconstructed by both activists and advocates. While many scholars currently tend to highlight the relational character of spaces, this study – acknowledging that seeing regions as relational or territorial is a highly contextual matter – emphasizes the territorial approach by stressing the multiple layers of borders and how they help to constitute and nurture regional identity. Focusing on deinstitutionalization of a region, it is argued here that regional restructuring can trigger activism, as proved by the activist movement at issue in the case study. This case study of a merger between two municipalities in Finland illustrates that when threatened with integration, (old) regions seem to be of especial importance as bordered territories of identification.     

Mass exchange in close binaries on the dynamical time scale during the stage of contracting onto the main sequence

We consider mass exchange in close binaries containing low-mass, fully convective components on the dynamical time scale. We present the results of three-dimensional hydrodynamical simulations of this process in close binaries contracting onto the main sequence (binary pre-MS stars). Our results suggest that some systems with superplanets could be formed by this process, which could be considered a special type of binary star. We have determined the ranges of the relative donor masses that allow the merger of the binary components and the formation of systems with superplanets or the survival of the binary during the mass exchange. These process should result in a deficit of binaries with similar component masses.     

利用DEM提取流域水系时洼地与平地的处理方法

在利用数字高程模型(DEM)模拟坡面流提取流域水系特征过程中,对洼地和平地的处理是首先需要解决的关键问题。针对现有方法对复杂地形DEM中平地、洼地及其复合情形处理效率和效果的不佳,提出了洼地的分类与归并、有效填洼、平地的分类、基于出流代价的河谷平地排水流向构建等新的处理方法,并在开发的软件系统中得到实现。实验结果表明:采用该方法可对复杂洼地进行有效处理,构建的河谷平地水流流向在顾及周边地形的同时向可能形成的河道收敛,避免了平行河道、伪河道等奇异河道的产生,由此提取的流域水系与实际自然水系基本一致。     

Necessary restructuring or globalization failure? Shifts in regional supplier relations after the merger of the former German Hoechst and French Rhône-Poulenc groups

A large part of the work in economic geography and other social sciences surrounding globalization processes has focused on the prospects of economic growth due to the establishment of global production chains and the rise of new clusters of industrial activity. In recent years, much less attention has been paid to former growth industries and regions that have suffered from the negative consequences of internationalization processes. This paper will explore the cases of two chemical regions, i.e. southern Hessen, Germany and Rhône-Alpes, France. Both regions were forced to undergo drastic restructuring since the mid 1990s due to the merger of the chemical groups Hoechst and Rhône-Poulenc into Aventis. The paper argues that it is beneficial to develop a relational perspective of economic action and interaction in order to better understand these regional transformations and restructuring processes and their consequences. Instead of investigating the development of activities, which became the core operations at Aventis, we will focus on other activities that were considered less important and, consequently, split off. In analyzing the logic of restructuring and the associated changes in regional supplier relations, this paper aims to contribute to a relational understanding of economic globalization and its associated threats to regional development by focusing on agents who are subject to negative restructuring consequences.     

Sudden surface collapse disasters caused by shallow partial mining in Datong coalfield,China

Numerous sudden surface collapses induced by shallow partial mining in the Datong Jurassic coal seam have caused fatalities, significant property losses and brought about harmful results to the environment. By introducing efficient pillar widths and using the Voronoi diagram, irregular pillar stability can be estimated rationally. Theoretical analysis and numerical simulation demonstrate that the failure of a single pillar increases the load on surrounding pillars. If the magnitude of the transferred load is sufficiently high, the adjoining pillars will also fail in a chain reaction. This can be interpreted by the merger of inner stress arches combined with the external stress arch. In this paper, the evolution mode of sudden surface collapse caused by shallow partial mining is proposed and has been verified by ‘similar material simulation.’ Finally, the potential of sudden surface collapse is determined and an example of collapse prediction and prevention of surface building damage with relocation is given.