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Application of low-temperature thermochronology on ore deposits preservation framework in South China:a review

Acta Geochimica 2022年第2期41卷 165-184页

作者： Kang min Jian-feng Gao State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China University of Chinese Academy of Sciences Beijing 100049China

South China can be divided into four metallogenic belts:The Middle-Lower Yangtze Metallogenic Belt(MLYB),Qinzhou-Hangzhou Metallogenic Belt(QHMB),Nanling Metallogenic Belt(NLMB),and Wuyi Metallogenic Belt(WYMB).The major mineralization in the four metallogenic belts is granite-related Cu–Au–Mo and porphyrite Fe-apatite,porphyry Cu(Au),and epithermal Pb–Zn–Ag,hydrothermal Cu–Au–Pb–Zn–Ag,and granite-related skarn-type and quartz-veins W–Sn,respectively.Low-temperature thermochronology,including fissiontrack and U-Th/He dating,has been widely used to constrain tectonic thermal evolution and ore deposits preservation.Understanding fission-track annealing and He diffusion kinetics in accessory minerals,such as zircon and apatite,is essential for dating and applications.In this study,previous zircon fission-track(ZFT)and apatite fission-track(AFT)ages in South China were collected.The result shows that the ZFT ages are mainly concentrated at140–90 Ma,and the AFT ages are mainly distributed at70–40 Ma.The age distribution and inversion temperature–time paths reveal heterogeneous exhumation histories in South China.The MLYB experienced Late CretaceousCenozoic extremely slow exhumation after rapid cooling in the Early Cretaceous.The northern QHMB(i.***.from southern Anhui province to the Hangzhou Bay)had a relatively faster rate of uplifting and denudation than the southern QHMB in the Cretaceous.Subsequently,the northern QHMB rapidly exhumed,while the continuously slow exhumation operated the southern QHMB in the Cenozoic.The southern NLMB had a more rapid cooling rate than the northern NLMB during the Cretaceous time,and the whole NLMB experienced rapid cooling in the Cenozoic,except that the southern Hunan province had the most rapid cooling rate.The WYMB possibly had experienced slow exhumation since the Late Cretaceous.The exhumation thickness of the four metallogenic belts since90 Ma is approximately calculated as follows:the MLYB≤3.5 km,the northern QHMB concentrated at3.5–5.5 km,and the southern QHMB usually less th

关键词： Low-temperature thermochronology Fissiontrack annealing and He diffusion kinetics South China Exhumation history Deposits preservation

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Lyapunov-Based Output Containment Control of Heterogeneous Multi-Agent Systems With Markovian Switching Topologies and Distributed Delays

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IEEE/CAA Journal of Automatica Sinica 2023年第6期10卷 1421-1433页

作者： Haihua Guo min Meng Gang feng the Department of Biomedical Engineering City University of Hong KongHong KongChina the Department of Control Science and Engineering College of Electronics and Information Engineeringand Shanghai Research Institute of Intelligent Autonomous SystemsTongji UniversityShanghai 200092China

This paper considers the mean square output containment control problem for heterogeneous multi-agent systems(MASs)with randomly switching topologies and nonuniform distributed delays.By modeling the switching topologies as a continuous-time Markov process and taking the distributed delays into consideration,a novel distributed containment observer is proposed to estimate the convex hull spanned by the leaders'states.A novel distributed output feedback containment controller is then designed without using the prior knowledge of distributed delays.By constructing a novel switching Lyapunov functional,the output containment control problem is then solved in the sense of mean square under an easily-verifiable sufficient condition.Finally,two numerical examples are given to show the effectiveness of the proposed controller.

关键词： Heterogeneous multi-agent systems Lyapunov method Markovian switching topologies output containment control time delays

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Insight into the photoexcitation effect on the catalytic activation of H_(2) and C-H bonds on TiO_(2)(110)surface

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Chinese Chemical Letters 2022年第10期33卷 4705-4709页

作者： min Zhou Hai-feng Wang Key Laboratory for Advanced Materials Centre for Computational Chemistry and Research Institute of Industrial CatalysisEast China University of Science and TechnologyShanghai 200237China

Semiconductor photocatalysis holds great promise for breaking the inert chemical bonds under mild condition;however,the photoexcitation-induced modulation mechanism has not been well understood at the atomic level.Herein,by performing the DFT+U calculations,we quantitatively compare H_(2) activation on rutile TiO_(2)(110)under thermo-versus photo-catalytic condition.It is found that H2 dissociation prefers to occur via the heterolytic cleavage mode in thermocatalysis,but changes to the homolytic cleavage mode and gets evidently promoted in the presence of photoexcited hole(h^(+)).The origin can be ascribed to the generation of highly oxidative lattice O-radical(O_(br)^(·−))with a localized unoccupied O-2p state.More importantly,we identify that this photo-induced promotion effect can be practicable to another kind of important chemical bond,i.e.,C-H bond in light hydrocarbons including alkane,alkene and aromatics;an exception is the C(sp^(1))-H in alkyne(HC≡CH),which encounters inhibition effect from photoexcitation.By quantitative analysis,the origins behind these results are attributed to the interplay between two factors:C-H bond energy(E_(bond))and the acidity.Owing to the relatively high E_(bond) and acidity,it favors the C(sp^(1))-H bond to proceed with the heterolytic cleavage mode in both thermo-and photo-catalysis,and the photoexcited O_(br)^(·−)is adverse to receiving the transferred proton.By contrast,for the other hydrocarbons with moderate/low E_(bond),the O_(br)^(·−)would enable to change their activation mode to a more favored homolytic one and evidently decrease the C-H activation barrier.This work may provide a general picture for understanding the photocatalytic R-H(R=H,C)bond activation over the semiconductor catalyst.

关键词： Density functional theory calculation Photocatalysis H_(2)activation C-H bond activation TiO_(2)

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Applicability of discrete element method with spherical and clumped particles for constitutive study of granular materials

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第1期14卷 240-251页

作者： Tongming Qu min Wang Yuntian feng Zienkiewicz Centre for Computational Engineering College of EngineeringSwansea UniversitySwanseaWales SA18EPUK T-3 Fluid Dynamics and Solid Mechanics Group Theoretical DivisionLos Alamos National LaboratoryLos AlamosNM87545USA

Discrete element method(DEM)has been intensively used to study the constitutive behaviour of granular materials.However,to what extent a real granular material can be reproduced by virtual DEM simulations remains unclear.This study attempts to answer this question by comparing DEM simulations with typical features of experimental granular materials.Three groups of models with spherical and clumped particles are investigated from four perspectives:(i)deviatoric stress and volumetric behaviour;(ii)critical state behaviour;(iii)stress-dilatancy relationship;and(iv)the evolution of principal stress ratio against axial strain.The results demonstrate that DEM with spherical or clumped particles is capable of qualitatively describing macroscopic deviatoric stress responses,volumetric behaviour,and critical state behaviour observed in experiments for granular materials.On the other hand,some qualitative deviations between experiments and the investigated DEM simulations are also observed,in terms of the stress-dilatancy behaviour and principal stress ratio against axial strain,which are proven to be critical for constitutive modelling.The results demonstrate that DEM with spherical or clumped particles may not necessarily fully capture experimental features of granular materials even from a qualitative perspective.It is thus encouraged to thoroughly validate DEM with experiments when developing constitutive models based on DEM observations.

关键词： Discrete element method(DEM) Granular materials Constitutive behaviour Deviatoric hardening model Rolling resistance model Irregular particles

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The composite X-ray spectra of radio-loud and radio-quiet SDSS quasars

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Research in Astronomy and Astrophysics 2021年第1期21卷 33-44页

作者： min-Hua Zhou min-feng Gu Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy ofSciences80 Nandan RoadShanghai 200030China University of Chinese Academy of Sciences 19A Yuquan RoadBeijing 100049China

We present a study of the X-ray emission for a sample of radio-detected quasars constructed from the cross-matches between SDSS,FIRST catalogs and XMM-Newton archives.A sample of radio-quiet SDSS quasars without FIRST radio detection is also assembled for comparison.We construct the optical and X-ray composite spectra normalized at rest frame 4215 A(or 2200 A)for both radio-loud quasars(RLQs)and radio-quiet quasars(RQQs)at z≤3.2,with matched X-ray completeness of 19%,redshift and optical luminosity.While the optical composite spectrum of RLQs is similar to that of RQQs,we find that RLQs have a higher X-ray composite spectrum than RQQs,consistent with previous studies in the literature.By dividing the radio-detected quasars into radio loudness bins,we find the X-ray composite spectra are generally higher with increasing radio loudness.Moreover,a significant correlation is found between the optical-to-X-ray spectral index and radio loudness,and there is a unified multi-correlation between the radio and X-ray luminosities and radio loudness in radio-detected quasars.These results could be possibly explained with the corona-jet model,in which the corona and jet are directly related.

关键词： methods:statistical catalogs quasars:general X-rays:general

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What decarbonized the residential building operation worldwide since the 2000s

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Petroleum Science 2022年第6期19卷 3194-3208页

作者： min-Da Ma min-Xia Chen Wei feng Jing-Wen Huo Building Technology&Urban Systems Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720United States School of Management Science and Real Estate Chongqing UniversityChongqing400045PR China Department of Earth System Science Tsinghua UniversityBeijing100084PR China

Decarbonization in operational residential buildings worldwide has become critical in achieving the carbon neutral target due to the growing household energy demand.To accelerate the pace of global carbon neutrality,this study explores the operational carbon change in global residential buildings through the generalized Divisia index method and decoupling analysis,considering the decarbonization levels of residential buildings at different scales.The results show that(1)most of the samples showed a decrease in the total emissions from 2000 to 2019.Except for China and the United States(US),the carbon emissions in global residential building operations decreased by 7.95 million tons of carbon dioxide(MtCO_(2))per year over the study period.Emissions per gross domestic product(GDP)was the most positive driver causing the decarbonization of residential buildings,while GDP was the most negative driver.(2)Carbon intensity was essential to achieving a strong decoupling of economic development and carbon emissions.The US almost consistently presented strong decoupling,while China showed weak decoupling over the last two decades.(3)The pace of decarbonization in global residential building operations is gradually slowing down.From 2000 to 2019,decarbonization from residential buildings across 30 countries was 2094.3 MtCO_(2),with a decarbonization efficiency of 3.4%.Overall,this study addresses gaps in evaluating global decarbonization from operational residential buildings and provides a reference for evaluating building decarbonization by other emitters.

关键词： Global residential building Operational decarbonization Generalized divisia index method Decoupling elasticity Building decarbonization strategies

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Effect of morphological gene mutation and decay on energy dissipation behaviour of granular soils

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第4期24卷 303-318页

作者： Wei XIONG Qi-min ZHANG Jian-feng WANG Department of Architecture and Civil Engineering City University of Hong KongHong KongChina Shenzhen Research Institute of City University of Hong Kong Shenzhen 518057China

In this paper,the X-ray micro-computed tomography(X-rayμCT),spherical harmonical-based principal component analysis(SH-PCA),and discrete element method(DEM)were incorporated to generate virtual samples with morphological gene mutation at different length scales.All samples were subjected to axial compression and constant confining stress.The effects of multiscale particle morphology on the stress-strain and energy storage/dissipation responses of granular soils were investigated.It is found that:(a)the effects of particle morphology on the initial stiffness,stress-strain,volumetric strain,and frictional energy dissipation behaviours are more pronounced for looser samples than for denser ones;(b)among different length scales,the particle morphology at the local roundness-level outperforms the one at the general form-level in dictating the macro-scale responses of granular soils;(c)the energy dissipation of a granular assemblage is a result of competition between particle morphology and initial void ratio.

关键词： X-ray micro-computed tomography(X-rayμCT) Spherical harmonic analysis(SHA) Discrete element method(DEM) Morphological gene mutation Energy dissipation

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Toward a “Green Revolution” for Soybean

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Molecular Plant 2020年第5期13卷 688-697页

作者： Shulin Liu min Zhang feng feng Zhixi Tian State Key Laboratory of Plant Cell and Chromosome Engineering Institute of Genetics and Developmental BiologyInnovative Academy of Seed DesignChinese Academy of SciencesBeijing 100101China College of Advanced Agricultural Sciences University of Chinese Academy of SciencesBeijing 100049China

Soybean(Glycine max),as an economically important food and oilseedcrop,is a major source of plant proteins and oils.Although considerable progress has been made in increasing the yields of rice,wheat,and maize through the“Green Revolution”,little improvements have been made for soybean.With the increasing demand of soybean production and the rapid development of crop breeding technologies,time has come for this important crop to undergo a Green Revolution.Here,we briefly summarize the history of crop breeding and Green Revolution in other crops.We then discuss the possible directions and potential approaches toward achieving a Green Revolution for soybean.We provide our views and perspectives on how to breed new soybean varieties with improved yield.

关键词： soybean yield Green Revolution

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Generating diverse clothed 3D human animations via a generative model

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Computational Visual Media 2024年第2期10卷 261-277页

作者： min Shi Wenke feng Lin Gao Dengming Zhu School of Control and Computer Engineering North China Electric Power UniversityBeijing 102206China Institute of Computing Technology Chinese Academy of SciencesBeijing 100190China

Data-driven garment animation is a current topic of interest in the computer graphics industry.Existing approaches generally establish the mapping between a single human pose or a temporal pose sequence,and garment deformation,but it is difficult to quickly generate diverse clothed human animations.We address this problem with a method to automatically synthesize dressed human animations with temporal consistency from a specified human motion label.At the heart of our method is a twostage strategy.Specifically,we first learn a latent space encoding the sequence-level distribution of human motions utilizing a transformer-based conditional variational autoencoder(Transformer-CVAE).Then a garment simulator synthesizes dynamic garment shapes using a transformer encoder-decoder architecture.Since the learned latent space comes from varied human motions,our method can generate a variety of styles of motions given a specific motion label.By means of a novel beginning of sequence(BOS)learning strategy and a self-supervised refinement procedure,our garment simulator is capable of efficiently synthesizing garment deformation sequences corresponding to the generated human motions while maintaining temporal and spatial consistency.We verify our ideas experimentally.This is the first generative model that directly dresses human animation.

关键词： Transformer garment animation conditional variational autoencoder(CVAE) computer graphics

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Towards Interpretable Defense Against Adversarial Attacks via Causal Inference

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Machine Intelligence Research 2022年第3期19卷 209-226页

作者： min Ren Yun-Long Wang Zhao-feng He University of Chinese Academy of Sciences Beijing 100190China Center for Research on Intelligent Perception and Computing National Laboratory of Pattern RecognitionInstitute of AutomationChinese Academy of SciencesBeijing 100190China Laboratory of Visual Computing and Intelligent System Beijing University of Posts and TelecommunicationsBeijing 100876China

Deep learning-based models are vulnerable to adversarial attacks. Defense against adversarial attacks is essential for sensitive and safety-critical scenarios. However, deep learning methods still lack effective and efficient defense mechanisms against adversarial attacks. Most of the existing methods are just stopgaps for specific adversarial samples. The main obstacle is that how adversarial samples fool the deep learning models is still unclear. The underlying working mechanism of adversarial samples has not been well explored, and it is the bottleneck of adversarial attack defense. In this paper, we build a causal model to interpret the generation and performance of adversarial samples. The self-attention/transformer is adopted as a powerful tool in this causal model. Compared to existing methods, causality enables us to analyze adversarial samples more naturally and intrinsically. Based on this causal model, the working mechanism of adversarial samples is revealed, and instructive analysis is provided. Then, we propose simple and effective adversarial sample detection and recognition methods according to the revealed working mechanism. The causal insights enable us to detect and recognize adversarial samples without any extra model or training. Extensive experiments are conducted to demonstrate the effectiveness of the proposed methods. Our methods outperform the state-of-the-art defense methods under various adversarial attacks.

关键词： Adversarial sample adversarial defense causal inference interpretable machine learning transformers

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