Exploring the dynamics of the disaggregated intercity corporate network in the Yangtze River Delta,China: a relational event approach

Journal of Geographical Systems - There has been a proliferation of studies trying to explain the driving forces behind the formation and evolution of intercity corporate networks. Previous...     

Characteristics of gas disaster in the Huaibei coalfield and its control and development technologies

The Huaibei coalfield is in the East China Economic Area, which is rich in coal and gas resources. However, hundreds of coal and gas outburst accidents have occurred because of the complex geological structures of the coalfield. Based on theoretical analysis and field statistics, the characteristics of regional geological structures and the coal measure strata evolution in the Huaibei coalfield were researched, and gas resource distribution and gas parameters were statistically analyzed to determine the dominant controlling factors of gas occurrence and gas dynamic disaster. The results indicated that the Huaibei coalfield has undergone complex tectonic evolution, causing obvious differences in gas storage in different blocks of different mining areas, which exhibits a pattern of high amounts of gas in the south and east, and low amounts of gas in the north and west. The coal seam and gas occurrence have a bipolar distribution in the coalfield caused by multiple tectonic movements, and they are deeply buried. Horizontal tectonic stress plays a dominant role in gas outburst, and the thermal evolution and trap effects of magma intrusion increase the possibility and extent of gas outburst. Considering coal seam and gas occurrence characteristics in the coalfield, we propose a new technology for deep coal reservoir reconstruction which combined present underground regional gas control methods and surface well extraction methods. The technology has three effects: developing gas resources, improving coal mining safety level and reducing greenhouse gas emissions, which has been practiced to be effective in coal mines in the Huaibei coalfield.     

Disaster Risk Science Development and Disaster Risk Reduction Using Science and Technology

Based on a series of international conferences for establishing HFA2 framework, this paper analyzed key issues of frontier of disaster risk science, integrated disaster prevention and mitigation strategies and integrated disaster risk governance. The future direction of disaster risk science was comprehensively discussed according to the widely discussed Post 2015 Hyogo Framework for Action (HFA2). It was proposed to deepen the cognition of the complexity of disaster system in terms of recognizing the complexity of disaster system from the interaction among various elements of the system, recognizing the complexity of climate change risk from the regional characteristics and formation mechanism of the global climate change and recognizing the complexity of the catastrophe risk from the regional development levels and patterns. Furthermore, it was suggested to make integrated disaster risk reduction strategies and countermeasures from the perspective of the complexity of the disaster system, including the establishment of regional integrated disaster risk governance framework to face climate change, the establishment of integrated disaster risk governance system in multi-spatial scale, the establishment of disaster risk governance financial system integrating the insurance, bonds and lottery, the establishment of consilience mode in integrated risk governance considering multi-stakeholder and the establishment of modeling and simulation platform integrated disaster risk information services and disaster risk reduction strategies. Finally, it was pointed out that the assessment of disaster risk levels for different regions in multi spatial scale can provide robust scientific support for integrated disaster risk governance of the world and regions, industries and enterprises so as to improve response to global change and guarantee a global and regional sustainable development.     

An approach to determining the thicknesses of shear bands with an echelon‐crack structure

In this paper, the internal structure of shear band is investigated, and a model of the shear band with an echelon crack structure is developed. The model assumes the shear band to be composed of two conjugate sets of echelon cracks, such that the smaller echelon cracks are embedded in the space of the larger ones. The additional strain induced by the echelon cracks and the anisotropic development of the compliance tensor in the shear band zone are analyzed. The critical crack density at the onset of shear band is obtained by applying the bifurcation condition. Deviating from previous approaches, the new procedure evaluates the thickness of shear band based on the geometrical characteristics of echelon crack arrays and the failure probability of grain boundaries in the longitudinal direction at the onset of shear band. Parametric analysis shows that grain size, internal friction angle, dilation angle, and failure probability of grain boundaries are the dominant factors that account for the shear band thickness. The calculated results are consistent with the experimental data available in the literature. The model soundly explains that the measurements of the shear band thickness are generally scattered, ranging from 4 to 30 (or even more) times the grain size. Copyright © 2011 John Wiley & Sons, Ltd.     

中国地理信息系统(GIS)发展状况的初步调查——由一组统计数据引起的思考

本文整理和统计了一组与中国GIS研究、教育、产业和市场相关的数据, 用于理解和评估中国的GIS产业状况和应用前景。     

Influences of Oyster Shell Soil Conditioner on Soil and Plant Rhizospheric Microorganisms

Oyster shell soil conditioner had significant influence on soil and rhizospheric microorganisms in their biomass, respiratory intensity and nutritional requirement. It could stimulate growth of soil and rhizospheric microorganisms, especially nitrogen-fixers, and intensify soil respiration in proportion to the dose and fertilizing time of the conditioner, leading to the increase in the number of nitrogen fixing bacteria and the decrease in the number of bacteria with special nutrition demands.     

磁场中p模/s模的转换及黑子对声波的吸收

在柱坐标下将黑子周围的环形区域（黑子除外）内的振荡分解为朝向黑子传播的（入射的）波和离开黑子传播的（出射的）波。对无黑子的环形区域内的振荡也进行了同样的分解。将黑子周围的入射波看成是被黑子磁流管磁化了的介质（介质内的磁场基本是水平的）中的波。而无黑子区的入射波看成是非磁化介质中的波。比较这两种波在固定波数下功率随频率的分布发现，在磁化介质中不同径向除ｎ的声波（ｐ模）频率系统降低，同时功率也降低，降低的功率最高达非磁化介质中波的功率的３０％。而比较在固定频率下功率随波数的分布发现，磁场中ｆ模及ｎ＝１，２，３的ｐ模的脊向高波数方向位移，功率的降低受频率调制，即声波在某些有限的频带中被吸收。这些观测表明，在磁场中ｐ模与磁声重力波（ＭＡＧ）产生了模式混合或耦合。模式混合的存在支持了模式转换作为ｐ模式被黑子吸收的机制的解释。此外，本文还分析了转换的ＭＡＧ波进入黑子磁流管（其中的磁场基本上是垂直的）后进一步被吸收，吸收的功率最高达ＭＡＧ波的２０％。在磁流管内没有进一步观测到模式的转换     

卸荷-增孔压条件下花岗岩残积土的力学特性

建（构）筑物因土中孔隙水压力升高而失稳破坏的情形屡见不鲜,常剪应力增孔压试验是相关研究的常用手段,但迄今鲜见考虑施工期开挖卸荷影响的试验研究。为探究初始卸荷对花岗岩残积土增孔压过程力学行为的影响,在常规增孔压试验中增加了初始卸荷阶段,开展了一系列考虑初始卸荷程度和卸荷滞时影响的卸荷-增孔压试验,分析土体变形、屈服和强度特性的初始卸荷效应与卸荷滞时效应,并与常规增孔压试验结果对比以揭示初始应力路径的影响。试验结果表明：增孔压过程的变形发展具有明显的阶段性,土体屈服后因其剪胀潜势和变形迅速而产生负超静孔压增量,有效平均应力转而增大;初始卸荷对增孔压过程土体力学性能具有明显的劣化作用,表现为刚度与屈服强度均随初始卸荷程度的增大而衰减;与被动压缩这种“加荷”式应力路径相比,初始卸荷的不利影响更为显著;土体力学性能的劣化随卸荷滞时的增长而加剧;屈服摩擦角随初始卸荷程度的增大逐渐减小,但始终大于临界状态摩擦角。     

Determination of Early Paleozoic metamorphic event in the Longshan Complex and its geological implicationSCIEI北大核心CSCD

长期以来,陇山杂岩的归属问题一直存在争议。本文对出露于秦岭-祁连山结合部位的陇山杂岩中石榴黑云斜长片麻岩和石榴斜长角闪岩进行了详细的岩石学、P-T温压计算、独居石和榍石U-Pb年代学研究。通过详细的岩相学观察,石榴黑云斜长片麻岩的变质峰期矿物组合为石榴子石+黑云母+斜长石+石英;石榴斜长角闪岩中则识别出了以石榴子石+单斜辉石+角闪石+斜长石+石英为峰期的变质矿物组合。通过传统温压计计算,石榴黑云斜长片麻岩(样品21LS40)和石榴斜长角闪岩样品(样品21LS42-1)的峰期变质P-T条件分别为700℃、0.72GPa和710℃、0.74GPa。激光剥蚀电感耦合等离子体质谱(LA-ICP-MS) U-Pb数据表明,石榴黑云斜长片麻岩中独居石的206Pb/238U的加权平均年龄为407~435Ma。石榴斜长角闪岩中榍石的下交点年龄分别为410±7Ma、409±5Ma和426±10Ma,榍石中Zr含量温度计的计算结果分别为750℃、751℃和748℃(假定压力为0.7GPa)。本文从变质作用的角度出发,将陇山杂岩与秦岭杂岩进行温压条件和变质时代对比研究,认为陇山杂岩与东秦岭杂岩高压-超高压岩石的最后一期退变质作用和西秦岭天水地区的秦岭杂岩麻粒岩相变质作用类似,可能为北秦岭造山带的西延。     

年轻造山带洋板块地层*

重点分析和总结了由显生宙增生复合体和造山带混杂岩重建的年轻造山带洋板块地层--太平洋洋板块地层,也简要介绍了东古印度洋(东新特提斯洋)和古亚洲洋洋板块地层的重建情况。通过对阿拉斯加南部中生代增生地体、俄罗斯远东和中国东北侏罗纪-早白垩世增生复合体、日本二叠纪-侏罗纪-白垩纪等不同时期的增生复合体、菲律宾侏罗纪增生复合体和美国加州海岸山脉中侏罗世-古新世弗朗西斯卡杂岩体等不同单元的岩石学特征、古生物地层学、年代地层学、因逆冲导致的构造叠置和混杂失序特征及演化阶段的分析,重建了太平洋洋板块地层。其中加州海岸山脉中侏罗世-古新世弗朗西斯卡杂岩体的研究比较深入,对该区俯冲带上叠蛇绿岩(大峡谷群弧前盆地蛇绿岩)和弗朗西斯卡北部马林海岬杂岩体(原岩为洋中脊玄武岩)进行了有效区分,不仅还原了太平洋板块的俯冲碰撞过程,还厘清了与之伴生的弧前盆地裂陷和扩张过程。另外,板块俯冲的滞留和幕式增生在活动时间较短的板块俯冲体系中可能不容易识别。