检索结果-南通市图书馆

Science China Earth Sciences 2023年第2期66卷 393-407页

作者： Ting HUANG huai zhang Yaolin SHI Key Laboratory of Computational Geodynamics College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing100049China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai519080China Beijing Yanshan Earth Critical Zone National Research Station Beijing101408China

China has planned and built several world-class cascade high dams in Jinsha River,Dadu River,Lancang River,and Yarlung Zangbo *** complex geological conditions in the reservoir area and numerous large-scale landslide bodies make the potential disaster risk of overflowing and cascade dam failure caused by landslide-generated tsunami under increasing severe ***,the study on describing and predicting the complex dynamic processes of generation,propagation,overflowing,wave setup,and the interaction between tsunami and lakeshore has not been systematically carried *** on the high-order Boussinesq-type equations,the development of the dynamic system of tsunamis in lakes coupled with the landslide process is realized using the finite volume method in this *** verify the accuracy and reliability of the study,the Xiluodu Reservoir is selected as the object to simulate the potential landslide-generated *** factors such as the generation and propagation of tsunamis,dam overflowing,and wave setup in the downstream river are quantitatively evaluated and *** constructed landslide with a total volume of 24×10^(6)m^(3)generates a near-field wave amplitude of about 28 *** maximum wave run-up height is about 95 m,the volume of the dam overflowing water up to 2.13×10^(6)m^(3),and the maximum wave height above the dam crest presents an M-shaped *** LGWs event raises the downstream water level by nearly 40 *** results show that the risk of landslide-generated tsunamis in the reservoir area in China cannot be *** developed Boussinesq-type equations coupled with the landslide dynamics can simulate the whole process of generation,propagation,runup,and estimating the overflowing water volume of the tsunamis in the lake,laying a foundation for the quantitative risk assessment of tsunamis in lakes of high cascade dams in China.

关键词： Tsunamis in lakes Landslide-generated tsunamis Boussinesq-type equations Numerical modeling The Xiluodu Reservoir

Seismicity changes and numerical simulation of coseismic deformation following the 2022 M_(s)6.8 Luding earthquake in Sichuan,China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第8期67卷 2507-2521页

作者： Qiu MENG Zitao WANG huai zhang Key Laboratory of Computational Geodynamics of Chinese Academy of Sciences College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China Institute of Earthquake Forecasting China Earthquake AdministrationBeijing 100036China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China Beijing Yanshan Earth Critical Zone National Research Station Beijing 101408China

The Xianshuihe fault is a major tectonic boundary between the Sichuan-Yunnan rhombic and Bayanhar blocks in Southwest *** an average left-lateral strike-slip movement of 10–15 mm/yr,it is a fast-moving strike-slip continental *** September 5,2022,the Ms6.8 Luding earthquake occurred along the Moxi segment of the Xianshuihe fault,reaching a maximum intensity of IX and resulting in a significant number of casualties and severe property *** earthquake broke the long-standing seismic quiescence of the Xianshuihe fault,which lasted for more than 40 years,and was followed by a significant number of *** outstanding question is how the behavior of the Xianshuihe fault and major earthquakes changed following this *** this study,we examined the changes in regional seismicity following the Luding earthquake and identified the potential for future strong earthquakes along the Xianshuihe *** used a finite element numerical method to simulate the environment of the seismogenic fault and its adjacent *** addition,we used the coseismic slip model of the Luding earthquake with the split-node method to calculate how the stress and strain fields in the surrounding area were affected by the2022 *** stress changes were resolved in the main faults,and the seismicity of adjacent faults was analyzed in conjunction with the observed seismic *** results indicate that regional tectonic movement primarily occurred to the southeast along the Moxi *** stress field is approximately north-south in tension and east-west in *** in the stress field in the epicentral region of the Luding earthquake exceeded 1 *** maximum displacement of the coseismic deformation field was concentrated between Moxi town and Tuanjie village,and the Coulomb stress of the fault zone in this region experienced the largest ***,the b-value of the Gutenberg-Richter magnitude-frequency relationship at the epicenter a

关键词： Luding earthquake Seismicity Coulomb failure stress change Finite element numerical simulation

Concentrated Trading and the Survival of Overconfident Traders

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2019年第4期35卷 753-760页

作者： huai-nian zhang De-qing ZHOU Mathematics School & Institute Jilin University Changchun 130012 China Department of Mathematics and Physics Beijing Institute of Petrochemical Technology Beijing 102617 China School of Finance Central University of Finance and Economics Beijing 100081 China

We build a strategic trading model where the overconfident trader earns more than the rational trader and the mechanism for this result differs from that of Kyle and Wang(1997). In this paper, discretionary and nondiscretionary liquidity traders coexist. The overconfident insider is less worried by the market maker and thus induces a lower liquidity cost. In this way, he attracts all the trading from the discretionary liquidity traders, which enables the survival of the overconfident trader.

关键词： strategic trading concentrated trading overconfidence

Preprocessing photospheric vector magnetograms for nonlinear force-free field extrapolation of the global corona

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2018年第7期18卷 113-124页

作者： Ai-Ying Duan huai zhang Key Laboratory of Computational Geodynamics University of Chinese Academy of Sciences SIGMA Weather Group State Key Laboratory for Space Weather National Space Science Center Chinese Academy of Sciences Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and Technology

Nonlinear force-free magnetic field （NLFFF） extrapolation based on the observed photo- spheric magnetic field is the most important method to obtain the coronal magnetic field nowadays. However, raw photospheric magnetograms contain magnetic forces and small-scale noises, and fail to be consistent with the force-free assumption of NLFFF models. The procedure for removing the forces and noises in observed data is called preprocessing. In this paper, we extend the preprocessing code of Jiang ＆ Feng to spherical coordinates for a full sphere. We first smooth the observed data with Gaussian smoothing, and then split the smoothed magnetic field into a potential field and a non-potential field. The potential part is computed by a numerical potential field model, and the non-potential part is prepro- cessed using an optimization method to minimize the magnetic forces and magnetic torques. Applying the code to synoptic charts of the vector magnetic field from SDO/HMI, we find it can effectively reduce the noises and forces, and improve the quality of data for a better input which will be used for NLFFF extrapolations applied to the global corona.

关键词： magnetic fields - magnetohydrodynamics (MHD) - methods numerical - Sun corona

3D MHD simulation of the double-gradient instability of the magnetotail current sheet

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2018年第9期61卷 1364-1371页

作者： DUAN AiYing zhang huai LU Hao Yu Key Laboratory of Computational Geodynamics University of Chinese Academy of Sciences State Key Laboratory of Space Weather Chinese Academy of Sciences School of Space and Environment Beihang University

Flapping motion of the current sheet(CS) is an important physical process in the Earth's magnetotail. The magnetic doublegradient model, which includes both the instability and wave modes, offers a reasonable explanation for the exciting and propagation of the flapping wave. In this paper, we apply an advanced numerical magnetohydrodynamic(MHD) scheme(conservation element and solution element(CESE)-MHD) to simulate the magnetic double-gradient instability in an idealized current sheet that mimics the magnetotail configuration. We initialize the simulations with a numerically relaxed magnetotail equilibrium, in which the normal component of the magnetic field has a tailward gradient. It is confirmed in our simulation that the instability develops in the current layer. The growth rate of the instability yielded from the simulation is very close to the prediction of theory, with a relative deviation of only ten percent. The results demonstrate that the CESE-MHD scheme is very powerful in numerical study of the double-gradient mechanism of the CS flapping mode, and can be used for further investigations of the flapping motion in more realistic CS configurations.

关键词： Earth's magnetotail current sheet flapping magnetohydrodynamic numerical simulation

Finite element simulation of deformation and stress changes of Kalpin-Kemin fault system in the Southwest Tianshan Orogenic Belt

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2022年第5期65卷 863-873页

作者： Zitao WANG huai zhang Qiu MENG Yaolin SHI Key Laboratory of Computational Geodynamics University of Chinese Academy of SciencesBeijing 100049China

Under the shadow of the far-field effect of the India-Eurasia collision,the Tianshan orogenic belt underwent tectonic re-activation in the Cenozoic,accompanied by strong tectonic deformation and frequent large *** by two rigid cratonic blocks located in its north and south,a series of marginal foreland fold-and-thrust belts are developed within the Tianshan orogenic belt and continue to develop to the bilateral pull-apart ***,the faults in the orogenic belt are *** deformation caused by thrust-related structure accounts for larger than 50%of the total convergence of the Tianshan Mountains,which results in the most active structure with large earthquakes in the Tianshan ***,it is of great significance to study the dynamic process of the newly generated and reactivated thrust-nappe structures in Tianshan orogen via numerical *** paper selects a classical cross-section profile in the western segment of the Southwest Tianshan Mountains,which contains the Kalpin-Maidan-Nalati-Kemin fault system from the south to the *** attempt to establish a two-dimensional plane strain,viscoelastic finite element model,by treating the regional faults as a whole fault system and considering the topography,fault geometry,and GPS *** displacement and stress fields of the model are retrieved,the short-term cumulative deformation field of the overall fault system is analyzed,and the rate of Coulomb failure stress change of each fault is also *** results show that the deformation is concentrated in the middle and southern parts of the Southwest Tianshan *** contrast,the deformation of the Kemin fault in the north is relatively *** to the Coulomb failure stress changes of these four faults and the historical earthquake catalog,the potential seismicity of each fault is qualitatively *** preliminary results suggest that the possibility of large earthquake occurrence is higher in the

关键词： Tianshan orogenic belt Viscoelastic finite element Coulomb failure stress change Seismicity

Numerical investigation on the geodynamical mechanism of the first major shock of 2006 Pingtung M_w7.0 earthquake

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2011年第5期54卷 631-639页

作者： SUN YuJun zhang huai SHI YaoLin Laboratory of Computational Geodynamics Graduate University of Chinese Academy of Sciences Beijing 100049 China

A strong Mw7.0 earthquake struck Pingtung offshore of Talwan on December 26, 2006. It consisted of two major events with an 8-minute interval. The first major shock occurred at 12：26 UTC. Focal mechanism results from Harvard, USGS, and BATS all indicated that the first major shock was a normal fault earthquake and the second one was dominated by strike-slip offsets. The location of the epicenter varied greatly in depth in different analyses. The latest results showed that the focal depth of the first shock was most probably around 40-44 km, placing the epicenter in the lithospheric mantle. However, this is not a location where earthquakes usually occur. To explore the geodynamical mechanism of this event, we carded out 2D finite element method （FEM） numerical experiments. Our primary results indicate that the geodynamical background, as well as the formation of Pingtung earthquake, is a consequence of the collision between Luzon arc and Chinese continental margin. Although Taiwan Island is in the shadow of NW-SE trending compressive collision zone, the existence of ductile lower crust leads to the decoupling between upper crust and lithospheric mantle. As lithospheric mantle subducts to the depth of around 250 km, the upper part of the bending subduction slab puts itself in an extensional state. The extensional stress from bending induced the occurrence of this normal fault earthquake at the critical point.

关键词： Pingtung earthquake geodynamical mechanism FEM simulation hierarchical rheology geodynamics

Asymptotic properties and expectation-maximization algorithm for maximum likelihood estimates of the parameters from Weibull-Logarithmic model

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2016年第4期31卷 425-438页

作者： GUI Wen-hao zhang huai-nian Department of Mathematics Beijing Jiaotong University Department of Mathematics and Physics Beijing Institute of Petro-chemical Technology

In this article, we consider a lifetime distribution, the Weibull-Logarithmic distri- bution introduced by [6]. We investigate some new statistical characterizations and properties. We develop the maximum likelihood inference using EM algorithm. Asymptotic properties of the MLEs are obtained and extensive simulations are conducted to assess the performance of parameter estimation. A numerical example is used to illustrate the application.

关键词： Maximum likelihood estimate EM algorithm Fisher information Order statistics Asymptoticproperties.

Asymmetric Information, Heterogeneous Prior Beliefs and Market Regulation

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2021年第3期37卷 459-476页

作者： Hong LIU Ying JIANG huai-nian zhang KLAS and School of Mathematics and Statistics Northeast Normal UniversityChangchun 130024China Department of Mathematics and Physics Beijing Institute of Petrochemical TechnologyBeijing 102617China

This paper studies the trading behavior of an irrational insider and its influence on the market equilibrium in the presence of market *** find that the market with only one insider with private information is almost close to a strong efficient market,under the condition of market *** the equilibrium,the probability of the insider being caught trading with private information is zero,which shows that the reasonable behavior of the regulator is to essentially give up *** the market efficiency and the irrational trader’s trading intensity all greatly improve because of the existence of the market regulation.

关键词： insider trading market regulation heterogeneous prior beliefs asymmetric information