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A new approach for inversion of receiver function for crustal structure in the depth domain

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Earth and Planetary Physics 2022年第1期6卷 83-95页

作者： TianYu zheng YuMei he Yue Zhu Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of Sciences(CAS)Beijing 100029China University of Chinese Academy of Sciences Beijing 100049China

A method for reconstructing crustal velocity structure using the optimization of stacking receiver function amplitude in the depth domain,named common conversion amplitude(CCA)inversion,is *** conversion amplitude in the depth domain,which represents the impedance change in the medium,is obtained by assigning the receiver function amplitude to the corresponding conversion position where the P-to-S conversion *** the conversion amplitude variation with depth as an optimization objective,imposing reliable prior constraints on the structural model frame and velocity range,and adopting a stepwise search inversion technique,this method efficiently weakens the tendency of easily falling into the local extremum in conventional receiver function *** tests show that the CCA inversion can reconstruct complex crustal velocity structures well and is especially suitable for revealing crustal evolution by estimating diverse velocity *** performance in reconstructing crustal structure is superior to that of the conventional receiver function imaging method.

关键词： crustal imaging receiver function depth domain inversion

Prodrugs of hydrogen sulfide and related sulfur species: recent development

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Chinese Journal of Natural Medicines 2020年第4期18卷 296-307页

作者： YUAN zheng-Nan zheng Yue-Qin WANG Bing-he Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State UniversityAtlantaGeorgia 30303USA

Hydrogen sulfide(H2S) is commonly referred to as the third gasotransmitter with firmly established physiological roles. Prodrug approaches have been broadly applied to deliver H2S for various applications and mechanistic studies. Since S-persulfidation and glutathionylation are known to be important in cellular signaling by sulfur species, there have been interests in developing donors of persulfide and glutathione persulfide as well. In this review, we discuss the recent development in area of prodrugs for various sulfur species.

关键词： H2S S-persulfidation Light-sensitive H2S prodrugs

An overview of emissions of SO2 and NOx and the long-range transport of oxidized sulfur and nitrogen pollutants in East Asia

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Journal of Environmental Sciences 2016年第6期28卷 13-25页

作者： Yu Qu Junling An Youjiang he Jun zheng State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Chinese Research Academy of Environmental Sciences Beijing 100012 China China-ASEAN Environmental Cooperation Center Ministry of Environmental Protection of the People's Republic of ChinaBeijing 100035 China

The long-range transport of oxidized sulfur（sulfur dioxide（SO2） and sulfate） and oxidized nitrogen（nitrogen oxides（NOx ） and nitrate） in East Asia is an area of increasing scientific interest and political concern. This paper reviews various published papers, including ground- and satellite-based observations and numerical simulations. The aim is to assess the status of the anthropogenic emissions of SO2 and NOx and the long-range transport of oxidized S and N pollutants over source and downwind region. China has dominated the emissions of SO2 and NOx in East Asia and urgently needs to strengthen the control of their emissions, especially NOx emissions. Oxidized S and N pollutants emitted from China are transported to Korea and Japan, due to persistent westerly winds, in winter and ***, the total contributions of China to S and N pollutants across Korea and Japan were not found to be dominant over longer time scales（e.g., a year）. The source–receptor relationships for oxidized S and N pollutants in East Asia varied widely among the different studies. This is because：（1） the nonlinear effects of atmospheric chemistry and deposition processes were not well considered, when calculating the source–receptor relationships;（2） different meteorological and emission data inputs and solution schemes for key physical and chemical processes were used; and（3） different temporal and spatial scales were employed. Therefore, simulations using the same input fields and similar model configurations would be of benefit, to further evaluate the source–receptor relationships of the oxidized S and N pollutants.

关键词： Long-range transport Sulfate Nitrate East Asia Source–receptor relationships

Reduction potential of the energy penalty for CO_(2) capture in CCS

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Frontiers in Energy 2023年第3期17卷 390-399页

作者： Yawen zheng Lin GAO Song he Hongguang JIN Laboratory of Integrated Energy System and Renewable Energy Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

CO_(2) capture and storage(CCS)has been acknowledged as an essential part of a portfolio of technologies that are required to achieve cost-effective long-term CO_(2) ***,the development progress of CCS technologies is far behind the targets set by roadmaps,and engineering practices do not lead to commercial *** of the crucial reasons for this delay lies in the unaffordable penalty caused by CO_(2) capture,even though the technology has been commonly recognized as *** the aspects of separation and capture technology innovation,the potential and promising direction for solving this problem were analyzed,and correspondingly,the possible path for deployment of CCS in China was *** the carbon neutral target recently proposed by the Chinese government,the role of CCS and the key milestones for deployment were indicated.

关键词： CO_(2)capture and storage(CCS) CO_(2)separation energy penalty

EFFECTS AND MECHANISMS OF EXTRINSIC STRENGTheNING DURING AGING FOR AL ALLOY 2090+Ce

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Transactions of Nonferrous Metals Society of China 1992年第2期2卷 76-81页

作者： Chen zheng he Ming Northwestern Polytechnical University XianShanxi 710072China

The influence of aging temperature and time on fracture feature of monotonic tensile samples of alumi-num-Iithium alloy 2090+Ce was *** effects and mechanisms of extrinsic strengthening during aging for this alloy with a flat unrecrystallized structure were *** mechanisms were analysed from four *** theory of extrinsic strengthening from the delamination strengthening was *** results in this research show that the strength and ductility of aluminum-lithium alloy with a flat unrecrystallized structure are superior to those with recrystallized *** reasons have been advanced for the ductility improvement effect of flat uncrystallized structure,including wedging action between flat grain,action of short-transverse delamination on impeding the growth of main crack,action on the reduction in the detrimental influence of weak grain boundaries and action on impeding the intergranular fracture on main fracture *** strengthening effect of flat uncrystallized structure is attributed to the extrinsic strengthening derived from delamination *** underage to peakage,the fracture mode of this alloy is transgranular fracture plus short-transverse *** tendency of short-transverse delamination in creases with aging,thereby enhancing the delamination strengtheniag *** overaging condition,the fracture mode is predominately intersubgranular,which results in the loss of delamination strengthening.

关键词： Aluminum-lithium Alloy Aging Extrinsic Strengthening Delamination Strengthening Grain Structure

Traffic flow cellular automaton model with bi-directional information in an open boundary condition

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Transportation Safety and Environment 2021年第1期3卷 1-9页

作者： Liang zheng zhengpeng he School of Traffic&Transportation Engineering Central South UniversityChangshaChina

With Connected Vehicle Technologies being popular,drivers not only perceive downstream traffic information but also get upstream information by routinely checking backward traffic conditions,and the backward-looking frequency or probability is usually affected by prevailing traffic ***,the bi-directional perception range of drivers is expected to significantly increase,which results in more informed and coordinated driving ***,we propose a traffic flow bi-directional CA model with two perception ranges,and perform the numerical simulations with the field data collected from a one-lane highway in Richmond,California,USA as the benchmark *** results show that the CA model can effectively reproduce the oscillation of relatively congested traffic and the traffic hysteresis *** adjusting the backward-looking probability and the perception range,the CA model can well simulate the travel times of all vehicles,and the generation and dissolution of traffic jams under various scenarios.

关键词： traffic flow cellular automaton backward-looking perception range hysteresis phenomenon

A three-stage model for the perforation of finite metallic plates by long rods at high velocities

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Defence Technology（防务技术） 2019年第3期15卷 409-418页

作者： Yu he Liu-yun Xu he-ming Wen zheng-cao Lu National Key Laboratory of Shock Wave and Detonation Physics Institute of Fluid Physics CAEP Mianyang 621900 China CAS Key Laboratory for Mechanical Behavior and Design of Materials University of Science and Technology of China Hefei Anhui 230027 China

A three-stage theoretical model is presented herein to predict the perforation of a thick metallic plate struck normally by a long rod at high velocities. The model is suggested on the basis of the assumption that the perforation of a thick metallic plate by a long rod can be divided into three stages:(1) initial penetration;(2) plug formation and (3) plug slipping and separation. Various analytical equations are derived which can be employed to predict the ballistic limit, residual velocity and residual length of the long rod. It is demonstrated that the present model predictions are in good agreement with available experimental results for the perforation of finite steel targets struck normally by steel as well as tungsten alloy long rods at high velocities. It is also demonstrated that the dynamic maximum shear stress of a plate material has strong effect on plug formation and plug thickness which, in turn, exerts considerable influence on the residual velocities and lengths of a long rod at impact velocities just above the ballistic limit.

关键词： Perforation Long rod Finite metallic plate Ballistic limit Residual velocity Residual length

DP-UserPro:differentially private user profile construction and publication

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Frontiers of Computer Science 2021年第5期15卷 197-206页

作者： zheng HUO Ping he Lisha HU Huanyu ZHAO Information Technology School Hebei University of Economics and BusinessShijiazhuang 050061China The Institute of Applied Mathematics Hebei Academy of SciencesShijiazhuang 050051China hebei Authentication Technology Engineering Research Center Shijiazhuang 050051China

User profiles are widely used in the age of big ***,generating and releasing user profiles may cause serious privacy leakage,since a large number of personal data are collected and *** this paper,we propose a differentially private user profile construction method DP-UserPro,which is composed of DP-CLIQUE and privately top-κtags ***-CLIQUE is a differentially private high dimensional data cluster algorithm based on *** multidimensional tag space is divided into cells,Laplace noises are added into the count value of each *** on the breadth-first-search,the largest connected dense cells are clustered into a *** a privately top-κtags selection approach is proposed based on the score function of each tag,to select the most importantκtags which can represent the characteristics of the *** and utility of DP-UserPro are theoretically analyzed and experimentally evaluated in the *** experiments are carried out with Tag Suppression algorithm on two real datasets,to measure the False Negative Rate(FNR)and *** results show that DP-UserPro outperforms Tag Suppression by 62.5%in the best case and 14.25%in the worst case on FNR,and DP-UserPro is about 21.1%better on precision than that of Tag Suppression,in average.

关键词： user profile DP-CLIQUE clustering differential privacy recommender system

Oscillating friction of nanoscale capillary bridge

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Friction 2022年第2期10卷 200-208页

作者： Shuai WU Yuqing he Quanshui zheng Ming MA Department of Engineering Mechanics.Tsinghua University Beijing 100084China Center for Nano and Micro Mechanics Tsinghua University.Beijing 100084China State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084.China Department of Mechanical Engineering.Tsinghua University Beijing 100084China

The presence of a capillary bridge between solid surfaces is ubiquitous under ambient ***,it leads to a continuous decrease of friction as a function of bridge ***,using molecular dynamics we show that for a capillary bridge with a small radius confined between two hydrophilic elastic solid surfaces,the friction oscillates greatly when decreasing the bridge *** underlying mechanism is revealed to be a periodic ordered-disordered transition at the liquid–solid *** transition is caused by the balance between the surface tension of the liquid–vapor interface and the elasticity of the *** balance introduces a critical size below which the friction *** on the mechanism revealed,a parameter-free analytical model for the oscillating friction was derived and found to be in excellent agreement with the simulation *** results describe an interesting frictional phenomenon at the nanoscale,which is most prominent for layered materials.

关键词： capillary bridge nano-confinement elasticity atomically smooth surface