检索结果-南通市图书馆

A Preliminary Study of Holocene Climate Change and Human Adaptation in the Horqin Region

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2014年第6期88卷 1784-1791页

作者： MU Yan QIN Xiaoguang ZHANG Lei XU Bing Key laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of Sciences

Human activity during the Holocene in the Horqin region, northeastern China, has been widely documented. As an important proxy record of human activity, black carbon（BC） in sediments has been linked to climate change and human adaptation. A loess-paleosol section located in south Horqin was chosen for this study. Holocene climate change and human adaptation to the environment were discussed by analyzing BC, organic carbon（OC） and other proxies. The conclusions included：（1） before 3900 cal BP, human activity was closely related to the natural environment and cultural development was dominated by climate change. For example, the rapid decline of the agrarian Hongshan culture was caused by a slight decrease in temperature at ~5000 cal BP;（2） during 3900-3200 cal BP, the heavy dependence of human societies on nature gradually lessened and the ability of those human societies to adapt to the environment was enhanced. However, the farming-dominated Lower Xiajiadian culture was nonetheless replaced by the pastoralist Upper Xiajiadian culture due to an extremely cooling event at ~3200 cal BP;（3） during the late Holocene period, the marked influence of climate change on human activity might have lessened as a result of a clear improvement in human labor skills. After this, human living styles were influenced by cultural developments rather than climate change because humans had mastered more powerful means of productivity.

关键词： black carbon climate change human adaptation archeological culture the Holocene Horqin Sandy Land

Mesozoic and Cenozoic tectonic evolution of the Longmenshan fault belt

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2009年第5期52卷 579-592页

作者： WANG ErChie Institute of Geology and geophysics State Key Laboratory of Lithospheric Evolution Chinese Academy of Sciences

The giant earthquake (M s=8.0) in Wenchuan on May 12, 2008 was triggered by oblique convergence between the Tibetan Plateau and the South China along the Longmenshan fault belt. The Longmenshan fault belt marks an imp... 详细信息

关键词： Wenchuan earthquake Longmenshan landslide flooding Chengdu Plain

Dynamics of a Rotating Sphere on Free Surface of Vibrated Granular Materials

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2018年第8期35卷 44-48页

作者： Adones B.Dengal Joel T.Maquiling geophysics research laboratory Department of Physics School of Science and EngineeringAteneo de Manila University Department of Physics College of Natural Sciences and Mathematics Mindanao State University

We investigate the rotational dynamics of a low-density sphere on the free surface of a vertically vibrated granular material（VGM）. The dynamical behavior of the sphere is influenced by the external energy input from an electromagnetic shaker which is proportional to ε,where ε is equal to the ratio between the square of the dimensionless acceleration Γ and the square of the vibration frequency f of the container. Empirical results reveal that as the VGM transits from local-to-global convection,an increase in ε generally corresponds to an increase in the magnitudes of the rotational ω（RS） and translational v（CM） velocities of the sphere, an increase in the observed tilting angle θ（bed） of the VGM bed, and a decrease in the time t（wall） it takes the sphere to roll down the tilted VGM bed and hit the container wall. During unstable convection, an increase in ε results in a sharp decrease in the sphere＇s peak and mean ω（RS）,and a slight increase in t（wall）.For the range of ε values covered in this study, the sphere may execute persistent rotation, wobbling or jamming, depending on the vibration parameters and the resulting convective flow in the system.

关键词： Dynamics of a Rotating Sphere on Free Surface of Vibrated Granular Materials

High pressure equation of state for molten CaCO_3 from first principles simulations

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2015年第1期34卷 13-20页

作者： Zhigang Zhang Zairong Liu Key laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences

Carbonate melts are important active metasomatic agents and efficient transport agents; their thermodynamic properties at high temperatures and pressures are therefore of considerable interest for various geochemica applications. However, due to the extreme challenges in relevant experiments, current knowledge of even the density of carbonate melts is limited. In this study, we provide high quality volumetric data of Ca CO3-melt from firs principles at high temperatures and pressures(up to3,500 K and 60 GPa). The accuracy of these data is demonstrated through comprehensive comparison with available experimental data and a thorough discussion of the predictability of the re-scaling method proposed in this study. Based on the simulations, an equation of state has been established that is critical to relevant highly disputed questions such as the decomposition and solidification boundaries of Ca CO3 melts, the latter of which is briefly discussed in this study with a newly derived ab initio melting curve to high pressures.

关键词：熔融曲线第一原理碳酸钙高压力模拟实验数据热力学性质 CaCO3

Innovation of experimental methodology for adsorbed gases on hydrocarbon-source rocks

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2013年第1期32卷 35-40页

作者： SHI Baoguang WANG Xiaofeng XU Yongchang ZHEN Jianjing The Key laboratory of Oil and Gas Resources Institute of Geology and Geophysics Chinese Academy of Sciences

As compared to the device developed by our predecessors, the newly developed adsorbed gas degasification-collection device has a series of advantages such as wide sample application range, large sample inlet, high vacuum, short-time sample smashing, low crushing temperature and water-free gas collection, which ensure the geochemical characteristics of acquired adsorbed gas samples to be the same as those of the adsorbed gases on corresponding hydrocarbon-source rocks. The results showed that the acquired adsorbed gases are composed mainly of hydrocarbon gas and carbon dioxide gas, with the hydrocarbon gas accounting for more than 80%, and can be measured reliably for their δ13C1-δ13C3 data, even δ13C4-δ13C5 data. The results of carbon isotope test and analysis satisfy the needs for the geochemical study and application of adsorbed gases. The above new techniques of experimental geochemistry are helpful for establishing the new direct natural gas-source correlation method, proving that the previous usual method of indirect natural gas-source correlation is scientific and authentic, thus providing the experimental basis for the study and application of adsorbed gases on hydrocarbon-source rocks.

关键词：气体收集烃源岩吸附地球化学特征实验地球化学创新验方应用程序

Renewed profile of the Mesozoic magmatism in Korean Peninsula: Regional correlation and broader implication for cratonic destruction in the North China Craton

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2016年第12期59卷 2355-2388页

作者： ZHAI MingGuo ZHANG YanBin ZHANG XiaoHui WU Fu Yuan PENG Peng LI Qiu Li HOU QuanLin LI TieSheng ZHAO Lei Key laboratory of Mineral Resources Institute of Geology and Geophysics Chinese Academy of Sciences State Key laboratory of Continental Geodynamics Northwest University State Key laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Key laboratory of Computational Earth Dynamics College of Earth Science University of Chinese Academy of Sciences

Widespread Mesozoic magmatism occurs in the Korean Peninsula(KP). The status quo is poles apart between the northern and southern parts in characterizing its distribution and nature, with the nearly absence of any related information in North Korea. We have the opportunity to have conducted geological investigations in North Korea and South Korea during the past ten years through international cooperation programs. This led to the revelation of a number of granitoids and related volcanic rocks and thus facilitates the comparison with those in East China and Japan. Mesozoic granitoids in the KP can be divisible into three age groups: the Triassic group with a peak age of ~220 Ma, the Jurassic one of ~190–170 Ma and the late Early Cretaceous one of ~110 Ma. The Triassic intrusions include syenite, calc-alkaline to alkaline granite and minor kimberlite in the Pyeongnam Basin of North Korea. They have been considered to form in post-orogenic settings related to the Central Asian Orogenic Belt(CAOB) or the Dabie-Sulu Orogenic Belt(DSOB). The Jurassic granitoids constitute extensive occurrence in the KP and are termed as the Daebo-period magmatism. They correlate well with coeval counterparts in NE China encompassing the northeastern part of the North China Craton(NCC) and the eastern segment of the CAOB. They commonly consist of biotite or two-mica granites and granodiorites, with some containing small dark diorite enclaves. On one hand, Early Jurassic to early Middle Jurassic magmatic rocks are rare in most areas of the NCC, whilst Middle-Late Jurassic ones are not developed in the KP. On the other hand, both NCC and KP host abundant Cretaceous granites. However, the present data revealed contrasting age peaks, with ~130–125 Ma in the NCC and ~110–105 Ma in the KP. Cretaceous granites in the KP comprise the dominant biotite granites and a few amphibole granites. The former exhibit mildly fractionated REE patterns and zircon εHf(t) values from ?15 to ?25, whereas the lat

关键词： Mesozoic granitoids Korean Peninsula Eastern China Japan Cratonic destruction

TRAJECTORY DIAGNOSIS OF AIR PARCELS IN HIGH-AND LOW-LEVEL JETS FOR A HEAVY RAINFALL CASE DURING MEIYU SEASON OF 1991

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta meteorologica Sinica 1993年第4期7卷 486-494页

作者：陶祖钰黄伟 National laboratory for Rainstorm research Chinese Academy of Meteorological Sciences Department of geophysics Peking University

Trajectory diagnostic methods were used to analyze air parcels of high- and low-level jets during the heavy rainfall of 4-6 July *** is found that air parcels above rainfall area travelled from the entrance of the high-level jet,passing through the jet center and reached the exit *** tropospheric divergence over rainfall area resulted from decelerative motion of the jet *** and moist southwest flow converged and ascended ahead of the low-level jet. The decreasing of low-level pressure as a result of high-level divergence that caused the low-level jet became unexpectedly strong.

关键词： heavy rainfall trajectory jet

Upper mantle seismic anisotropy beneath a convergent boundary:SKS waveform modeling in central Tibet

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2014年第4期57卷 759-776页

作者： ZHAO Liang ZHAO Ming LU Gang State Key laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences

This study used SKS waveforms from the International Deep Profiling of Tibet and the Himalayas(INDEPTH) III dataset and a new 2D method for modeling seismic waves in anisotropic media to construct an image of anisotropic structures beneath central Tibet.A preferred model revealed three-segment anisotropic structures in the upper mantle beneath the study *** modeling demonstrated that the anisotropy was mainly generated by the lithosphere but not the asthenosphere,and that an anisotropic model with a flatter axis of symmetry provides a more consistent interpretation of the observations than models having steeply dipping symmetry axes.A relatively low velocity zone may underlie or intermingle with the anisotropic structures in the northern portion of the *** tests also indicate that variations in the elastic constants and depth extent of the anisotropy assumed by the calculations do not affect the general conclusions,although trade-offs exist among certain model *** modeling results suggest that the complex seismic structures in central Tibet were associated with underthrusting of the Indian lithosphere beneath the Asian lithosphere;the inferred flat symmetry axis of the anisotropy was likely generated during this collision *** this were not the case,the inherited anisotropy would exhibit a steeply dipping axis of symmetry,parallel to the direction of underthrusting.

关键词： waveform modeling spectral element method upper mantle anisotropy central Tibet

Comparing the diurnal variations in the SuperMAG auroral electrojet indices SML and SMU

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2014年第29期59卷 3877-3883页

作者： Yuan Wang Aimin Du Gengxiong Chen Xin Cao Ying Zhang Min Li Xiaocan Liu Jianpeng Guo Key laboratory of Ionospheric Environment Institute of Geology and GeophysicsChinese Academy of Sciences Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of Sciences University of Chinese Academy of Sciences Institute of geophysics China Earthquake Administration State Key laboratory of Space Weather Center for Space Science and Applied ResearchChinese Academy of Sciences

Diurnal variations of the SuperMAG auroral electrojet indices(SML and SMU)were examined for the period of 1980–2010,and the differences between SML and SMU were especially *** diurnal variation of SML with a maximum at around 1100 UT has a prenoonpostnoon *** solstices,the diurnal variation of SML is much stronger than that at *** the SMU,two maxima are recorded in the diurnal variation with the bigger one at 1700 UT and the smaller one at 0400 *** seasonal variations are not obvious in the UT variation characteristics of SMU although the intensity of SMU is changed remarkably season by *** both SML and SMU,the contributing stations are located at higher geomagnetic latitude around 1600 UT and at lower geomagnetic latitude around 0400 *** results indicate that:(1)the SML is mostly controlled by the convection electric *** diurnal variation is mainly correlated with the equinoctial and R-M hypothesis;(2)the SMU is largely controlled by the ionospheric *** diurnal variation is tightly correlated with the solar radiation.

关键词： SMU SML 日变化电喷极光昼夜变化 UT变化季节变化