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591.
本文利用地震资料并结合地质资料,讨论了印度板块与欧亚板块在中国周边的相互作用及其对中国应力场的影响,指出两板块在喜马拉雅山前断裂地区碰撞,碰撞边界向西延续到35°N,74°E附近,其主要挤压方向为NNE,并形成SE方向的物质流动.帕米尔地区有强烈的构造运动,并存在俯冲带形态的构造.在26.5°N,97°E附近,板块边界的走向发生突变,并形成东倾的缅甸山弧俯冲带,但印度板块挤压造成的主压应力方向为NNE向.在安达曼-尼科巴-苏门答腊-爪哇岛弧,印度板块俯冲于欧亚板块之下,在中国南海一带形成NNW向或近Ns向的主压应力. 相似文献
592.
作者根据Ag2S-PbS,Ag2S-PbS-Sb2S3及各体系相平衡资科以及內蒙白音诺等矿床中各种矿物共生组合中方铅矿的成分,论证了银的赋存状态及其与伴生元素锑、铋的关系。在含银及低温条件下,银在方铅矿中形成独立的银锑硫盐矿物,这有利于银的回收。在含铋低温条件下,银在方铅矿中不可避免地有相当一部分呈固溶体的状态分散在晶格中,它不利于银的回收。因此,只需研究银的赋存状态及矿石或方铅矿中伴生元素锑、铋含量及其比例,即可对铅精矿中银的存在形式及回收率作出初步的评价。 相似文献
593.
用大量弹簧滑块组成的模型可以模拟地震的复杂性,本文以细胞自动机(CA)为数学工具,结合地震学和岩石力学的结果,考虑了能量的输入和损耗,进行了地震事件的数字模拟。对模型中输出的"地震"事件进行了时间和空间的多分形分析,并对自组织临界(SOC)状态进行了讨论,进而得到事件至少在时间域里的分布呈现出层次结构,符合自相似特征。本文的CA模型属于确定性的混沌系统,而对于处在SOC状态下的大量事件的频度和大小的统计与G-R指数律很好地吻合。结果表明,虽然自组织(SO)可能是更准确的地震表征,但SOC仍然是研究地震现象的很好的模式。 相似文献
594.
595.
An equation of state (EOS) explicit in Helmholtz free energy has been improved to calculate the PVTx and vapor–liquid phase equilibrium properties of CH4–CO2 fluid mixture. This EOS, where four mixing parameters are used, is based on highly accurate EOSs recommended by NIST for pure components (CH4 and CO2) and contains a simple generalized departure function presented by Lemmon and Jacobsen (1999). Comparison with experimental data available indicates that the EOS can calculate both vapor–liquid phase equilibrium and volumetric properties of this binary fluid system with accuracy close to that of experimental data up to high temperature and pressure within full range of composition. The EOS of CH4–CO2 fluid, together with the updated Gibbs free energy model of solid CO2 (dry ice), is applied to calculate the CH4 content (xCH4) and molar volume (Vm) of the CH4–CO2 fluid inclusion based on the assumption that the volume of an inclusion keeps constant during heating and cooling. diagrams are presented, which describe phase transitions involving vapor, liquid and CO2 solid phases of CH4–CO2 fluid inclusions. Isochores of CH4–CO2 inclusions at given and Vm can be easily calculated from the improved EOS. 相似文献
596.
The Southern Ocean is a strong sink for atmospheric CO2, making it especially vulnerable to ocean acidification (OA). The aragonite saturation state (Ωarg) of seawater has been used as an index for the estimation of OA, which plays a critical role in evaluating the living environment of marine calcified organisms. However, it is very difficult to perform the studies of OA and Ωarg in the Southern Ocean due to its harsh climate. Therefore, in order to better understand the OA and its further influences, the advances of Ωarg studies were summarized in the oceans surrounding the Antarctica. Significant spatial and temporal variations of surface seawater Ωarg are demonstrated in the Southern Ocean. In general, the surface seawater Ωarg shows a lower value in the off-shore areas than in the open oceans. And, Ωarg also exhibits a strong seasonal cycle with a higher value in summer than in winter. The distributions of Ωarg in vertical water column generally present a declining tendency from surface to bottom. In addition, the shoaling of Ωarg horizon at high latitude could be attributed to the ventilation and upwelling of deep waters in the Southern Ocean. There are many factors that could impact the Ωarg in the Southern Ocean, including sea ice melting, sea-air CO2 exchange, biological activities and hydrological processes, etc. Finally, the future changes and key scientific problems of OA in the Southern Ocean are proposed. 相似文献
597.
Knowledge of the full present-day stress tensor and pore pressure has significant applications in the exploration and production of conventional and unconventional hydrocarbon reservoirs. The Darling Basin of New South Wales, Australia, is an old sedimentary basin (Late Cambrian/Silurian to Early Carboniferous) in which there was limited information about the present-day stress field prior to this study. In this paper we evaluate the contemporary stress field of the Darling Basin using a dataset from recent exploration wells and perform a geomechanical risk assessment with respect to borehole stability, fracture/fault generation and reactivation. Our interpretations of borehole failures in borehole image logs reveal a prevailing east-west orientation of the maximum horizontal stress throughout the Darling Basin. The estimates of the magnitudes for the vertical, minimum and maximum horizontal stress in the studied wells indicate a transition between thrust and strike-slip faulting stress regime at 600–700 m depths, where the magnitude of vertical stress and minimum horizontal stress are close to each other. However, the presence of borehole breakouts and drilling-induced tensile fractures, that we observe in the image logs at greater depths (900–2100 m) indicate a transition into a strike-slip tectonic stress regime below a depth range of approximately 700–900 m. These findings are in agreement with overcoring stress measurements east and west of the investigated wells. Furthermore, there are several Neogene-to-Recent geological structures in the study area that indicate thrust faulting with an east-west oriented maximum horizontal stress orientation around this old sedimentary basin. The consistency between the orientation of maximum horizontal stress determined from wellbore data and neotectonic structures is significant, and implies that horizontal stress orientations derived from very recent geological features may be valuable inputs to geomechanical models in the absence of wellbore or other data. However, the recent surface geological structures suggest a thrust faulting stress regime that is in slight contrast to the transition between thrust and strike-slip stress regime (SH > Sh ∼ Sv) indicated by petroleum data, and highlights a potential pitfall of using neotectonic structures in geomechanical models. In particular, careful attention and verification should be made when using neotectonic structures for input, calibration or confirmation of geomechanical models, especially in intraplate tectonic settings such as Australia. 相似文献
598.
固态毫米波雷达探测模式的对比评估与分析 总被引:1,自引:1,他引:0
利用2014年广东阳江和青藏高原外场观测中多种探测仪器的观测资料,对比了灾害天气国家重点实验室与航天科工23所联合研制的固态毫米波雷达三种探测模式最小可测回波强度、可测液态水(冰水)含量、观测同一目标时回波强度的差异以及与K波段微降水雷达回波强度的差异等。结果表明:(1)毫米波雷达不同模式最小可测回波强度差异与理论差异一致,边界层模式和降水模式能观测近地面全部层云和积云,卷云能观测5km高度冰水含量在0.0007 g·m~(-3)以上的卷云,随着高度上升探测能力有所下降;(2)毫米波雷达使用不同模式观测同一目标时,不同观测模式宏观回波强度一致,大部分差异不超过3.5 dB;(3)K波段微降水雷达和Pasivel2激光雨滴谱仪的近地面回波强度一致,毫米波雷达与K波段微降水雷达存在系统差异。 相似文献
599.
Simone Scarpa 《Urban geography》2016,37(7):963-984
In recent years, residential segregation has become a major issue in the Swedish policy debate. The prevailing view is that residential segregation is a crucial contributing factor to the development of income inequality, since individual income prospects are thought to be influenced by the population characteristics of their neighbourhoods. This study takes the opposite approach and analyses the extent to which, in the period 1991–2010, rising income inequality contributed to the development of residential segregation by income in Swedish metropolitan areas. The period was characterized by unprecedented growth in income inequality, which was associated with a decline in the redistributive power of the welfare state. Residential segregation by income mirrored locally the general trend in income inequality. Another factor was the change in income dispersion in neighbourhoods, relative to the metropolitan areas as a whole, which indicates a tendency towards increased population homogeneity in neighbourhoods with respect to income. 相似文献
600.
海洋酸化是全球变化的一个关注点,南大洋CO2吸收量占海洋对人为CO2的吸收量的30%—40%,同时,南大洋是缓冲能力较低、生态系统脆弱的高纬海域,所以,理解南大洋海水酸化过程及其控制因素就显得尤为重要。海水酸化引起海水中碳酸根离子(CO2-3)的浓度、碳酸钙饱和度(Ω)降低,这对成钙类生物碳酸钙(包括文石和方解石)的形成有害,最终可能对生态系统造成危害。了解海洋酸化的影响、预测酸化对海水碳酸盐体系和生态系统的影响具有重要意义。因此,本文对目前南大洋的开阔大洋区以及两个具有代表性的边缘海和海湾的酸化研究概况进行了梳理,试图对南大洋表层海水酸化的研究进行概述、展望未来南大洋海洋酸化研究趋势并提出一些亟须解决的问题。 相似文献