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Layering of subcontinental lithospheric mantle

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Science Bulletin 2017年第14期62卷 1030-1034页

作者： ling chen State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences CAS Center for Excellence in Tibetan Plateau Earth Sciences University of Chinese Academy of Sciences

Recent seismic studies reveal a sharp velocity drop mostly at^70–100 km depth within the thick mantle keel beneath cratons, termed the mid-lithosphere discontinuity(MLD). The common presence of the MLD in cratonic regions indicates structural and property layering of the subcontinental lithospheric mantle(SCLM). The nature and origin of the MLD, and many issues associated with the layering of the SCLM are essential to understand the formation and evolution of continents, and have become frontier subjects in the Earth sciences.

关键词： Mid-lithosphere discontinuity Lithosphere-asthenosphere boundary Subcontinental lithospheric mantle Formation and evolution of continents

Twisted Hamiltonian Lie Algebras and Their Multiplicity-Free Representations

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Acta Mathematica Sinica,English Series 2011年第1期27卷 45-72页

作者： ling chen Institute of Applied Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 P. R. China

We construct a class of new Lie algebras by generalizing the one-variable Lie algebras generated by the quadratic conformal algebras （or corresponding Hamiltonian operators） associated with Poisson algebras and a quasi-derivation found by Xu. These algebras can be viewed as certain twists of Xu＇s generalized Hamiltonian Lie algebras. The simplicity of these algebras is completely determined. Moreover, we construct a family of multiplicity-free representations of these Lie algebras and prove their irreducibility.

关键词： Hamiltonian Lie algebras representation simplicity irreducibility

Upper crustal P-wave velocity structure beneath two volcanic areas in northern Iran

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Science China Earth Sciences 2017年第4期60卷 786-795页

作者： LU Yan chen ling Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China State Key Laboratory of Lithospherie Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Chinese Academy of Sciences Center for Excellence in Tibetan Plateau Earth Sciences Beijing 100101 China

Detailed information about the crustal structure is essential for better understanding the occurrence and mechanisms of earthquakes and *** we present a study of the upper crustal P-wave velocity structure of two seismically and volcanically active areas in northern Iran using the two-dimensional Pg travel time tomography *** imaging results suggest low velocities in the upper crust beneath the Damavand and Sahand-Sabalan volcanic areas in the central and western parts of northern Iran,*** upper crustal low velocities in these two areas roughly coincide with previously imaged low Pn velocity anomalies,suggesting that the Late Cenozoic volcanic activity was probably caused by the upwelling of hot materials from the *** image feature of the Pg velocity structure beneath the Sahand-Sabalan volcanic area further indicates that the hot materials stored in the upper crust beneath Sahand may be larger in size than those stored beneath *** of the Pg velocity images with the earthquake distribution in north Iran suggests that earthquakes mainly occur at moderately low velocity or low to high velocity boundary areas instead of significantly low or high velocity *** anisotropy results show that the Pg wave fast direction is consistent with the GPS direction at high Pg velocity areas and the fast direction is inconsistent with the GPS direction but consistent with the strike direction of faults at low velocity *** new upper crustal structural images provide the basic observation for better understanding of the regional seismicity and volcanism,and link the surface geological phenomena to deep crustal and mantle processes associated with the active tectonics in northern Iran.

关键词： Equatorial ionization anomaly Sudden stratospheric warming Ionosphere

Personal continuous route pattern mining

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第2期10卷 221-231页

作者： Qian YE ling chen Gen-cai chen School of Computer Science and Technologym Zhejiang University Hangzhou 310027 China

In the daily life,people often repeat regular routes in certain periods. In this paper,a mining system is developed to find the continuous route patterns of personal past trips. In order to count the diversity of personal moving status,the mining system employs the adaptive GPS data recording and five data filters to guarantee the clean trips data. The mining system uses a client/server architecture to protect personal privacy and to reduce the computational load. The server conducts the main mining procedure but with insufficient information to recover real personal routes. In order to improve the scalability of sequential pattern mining,a novel pattern mining algorithm,continuous route pattern mining(CRPM),is proposed. This algorithm can tolerate the different disturbances in real routes and extract the frequent patterns. Experimental results based on nine persons' trips show that CRPM can extract more than two times longer route patterns than the traditional route pattern mining algorithms.

关键词： Data mining Route pattern GPS Mobile phone

Evaluation of 3D crustal seismic velocity models in southwest China:Model performance,limitation,and prospects

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Science China Earth Sciences 2024年第2期67卷 604-619页

作者： Xin WANG ling chen Qi-Fu chen Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing100049China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China

Southwest China is a tectonically and seismically active region,witnessing strong deformation due to the collision between the Indian and Eurasian *** the subsurface velocity structure of this region is thus important in understanding the tectonics and geodynamic processes of continental collision and in mitigating seismic *** studies have provided various 3D seismic velocity models in southwest ***,discrepancies exist among these models,and less effort has been made to quantify the reliability and accuracy of these existing velocity *** this study,we use regional 3D waveform simulation to evaluate the performance of various regional crustal 3D velocity models in reproducing observed *** particularly focus on two recent earthquake sequence in the region,the 2021 Yunnan Yangbi MS_(6.4) earthquake sequence and the 2022 Sichuan Luding MS_(6.8) earthquake *** tested 3D velocity models include the Southwest China Community Velocity model V1.0,the Unified Seismic Tomography Models for Continental China Lithosphere V2.0,the adjoint full waveform tomography model of the crustal and upper mantle beneath Eastern Tibetan Plateau,and the shallow seismic structure model beneath continental *** results show that the tested 3D velocity models generally capture well long-period(<0.2 Hz)waveforms,indicating that the 3D models adequately resolve overall large-scale subsurface ***,the 3D synthetics show discrepancies in higher frequencies(0.05–0.3 Hz)and the performance of the 3D velocity models varies from region to region,suggesting that smaller scale heterogeneities are not well *** shallow velocity structures(<10 km)can improve the waveform fitting,emphasizing the importance of incorporating shallow structures in waveform *** full-waveform tomography model shows a slighter better performance than the other models,especially for the body-waves,highlighting the advantages

关键词： Southwest China Seismic tomography models Shallow Structures Waveform simulation Model evaluation

Hardware Materials in Molten Carbonate Fuel Cell:A Review

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Acta Metallurgica Sinica(English Letters) 2017年第4期30卷 289-295页

作者： ling chen Chao-Yi Yuh FuelCell Energy Inc.DanburyCT 06813USA

The high-temperature molten carbonate fuel cell is an ultra-clean and highly efficient power generator. It is operated at - 550-650 ℃, which is considered optimal in facilitating fast fuel cell reaction kinetics, utilizing waste heat efficiently, and allowing use of commercial construction materials. Commercial MW-size （mega watt） power plants of FuelCell Energy products have already been deployed worldwide. Metallic hardware materials are extensively utilized and may experience high-temperature reducing and oxidizing atmospheres in the presence of molten alkali carbonate electrolyte. Material selections are founded on many decades of focused research and development and field experience. Results to date show that the baseline stack module materials meet 5-year life goal and BOP （balance of plant） construction materials meet 20-year life goal. Material durability is well understood, and solutions are available to further extend the durability. This paper will review hardware materials experience and development approaches that would further reduce cost and extend life.

关键词： Molten carbonate fuel cell High-temperature materials Corrosion

Char Plant:A De Novo Open Chromatin Region Prediction Tool for Plant Genomes

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Genomics, Proteomics & Bioinformatics 2021年第5期19卷 860-871页

作者： Yin Shen ling-ling chen Junxiang Gao Hubei Key Laboratory of Agricultural Bioinformatics College of InformaticsHuazhong Agricultural UniversityWuhan 430070China National Key Laboratory of Crop Genetic Improvement Huazhong Agricultural UniversityWuhan 430070China

Chromatin accessibility is a highly informative structural feature for understanding gene transcription regulation,because it indicates the degree to which nuclear macromolecules such as proteins and RNAs can access chromosomal *** have shown that chromatin accessibility is highly dynamic during stress response,stimulus response,and developmental ***,physical access to chromosomal DNA in eukaryotes is highly ***,current technologies such as DNase-seq,ATAC-seq,and FAIRE-seq reveal only a portion of the open chromatin regions(OCRs)present in a given ***,the genome-wide distribution of OCRs remains *** this study,we developed a bioinformatics tool called Char Plant for the de novo prediction of OCRs in plant *** develop this tool,we constructed a three-layer convolutional neural network(CNN)and subsequently trained the CNN using DNase-seq and ATACseq datasets of four plant *** model simultaneously learns the sequence motifs and regulatory logics,which are jointly used to determine DNA *** of these steps are integrated into Char Plant,which can be run using a simple command *** results of data analysis using Char Plant in this study demonstrate its prediction power and computational *** our knowledge,Char Plant is the first de novo prediction tool that can identify potential OCRs in the whole *** source code of Char Plant and supporting files are freely available from https://***/Yin-Shen/Char Plant.

关键词： Open chromatin region Chromatin accessibility Convolutional neural network De novo prediction Plant genome

Hydrodynamic scaling and wave force estimation of offshore structures

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Acta Mechanica Sinica 2020年第6期36卷 1228-1237,I0002页

作者： Jifu Zho ling chen Xu Wang CAS Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing100049China

Offshore structures are generally classified as small-scale structures or large-scale *** wave forces are then estimated by Morison equation and diffraction/radiation theories,***,the classification criterion is not well *** the present paper,a numerical wave flume is established to simulate the wave forces acting on a fixed and vertical surface-piercing circular cylinder under linear *** solving Navier–Stokes equation and Euler equation with free surface involved,respectively,the viscous force and inertia force are separated *** variation of viscous force and inertia force with the cylinder diameter to wave length ratio is discussed in *** scale intervals for significant viscous and diffraction effects are *** error caused by neglecting viscous and diffraction forces is quantitatively *** on these analysis,the concept of medium-scale structure is proposed and the classification criteria for small-,medium-and large-scale structures are *** the meantime,the estimation methods of wave forces for different scales of structures are suggested.

关键词： Wave force Viscous effect Diffraction effect Medium-scale structure Numerical wave flume

Shear-wave velocity structures of the shallow crust beneath the Ordos and Sichuan Basins from multi-frequency direct P-wave amplitudes in receiver functions

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Science China Earth Sciences 2022年第5期65卷 810-823页

作者： chenxiao TANG ling chen Xu WANG State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Deep Earth Science Excellence and Innovation Center Chinese Academy of SciencesGuangzhou 510640China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

As the two largest cratonic basins in China,the Ordos Basin and the Sichuan Basin are of key importance for understanding the evolutionary history of the Chinese *** this study,the shear-wave velocity(V_(S))structures of the shallow crust(depth up to 10 km)beneath the two basins are imaged based on the frequency-dependence of direct P-wave amplitudes in receiver *** teleseismic data used in the study came from 160 broadband seismic stations,including permanent and temporary *** results show that the V_(S) and the thickness of the sediments in the Ordos Basin and the Sichuan Basin are respectively lower and thicker in the west than in the *** the Ordos Basin,the shallow crustal V_(S) increases gradually from 2.10 km s^(−1)in the northwest to 2.65 km s^(−1)in the southeast and the thickest sediments are 7–8 km in the northwest and 5 km in the *** the Sichuan Basin,the shallow crustal V_(S) increases from 2.4 km s^(−1) in the west to 2.7 km s^(−1)in the east and the thickness of the sediments decreases from>7 km in the west to 6 km in the *** east-west difference of the shallow crustal structures of the two basins may have been controlled by the Cenozoic India-Eurasia *** western parts of the basins near the collision have a higher deposition rate,while in the parts inside the basins far from the collision,the V_(S) slowly increases with depth,indicating that these areas have experienced a more uniform deposition *** addition,both basins are characterized by velocity structures that are higher along the edges and lower inside of the *** edges of the basins suffered strong denudation due to the uplifting and deformation influenced by tectonic *** downward gradient of the shear-wave velocity beneath the Ordos Basin is twice that of the Sichuan Basin,which may be caused by the different deposition and denudation rates of the two basins resulting from differences in structural evolution and thermal

关键词： Shallow crustal velocity structures Receiver function Frequency dependence Ordos Basin Sichuan Basin Tectonic evolution