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Electric-field-induced microstructure modulation of carbon nanotubes for high-performance supercapacitors

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Frontiers of Materials Science 2019年第3期13卷 270-276页

作者： Chengzhi LUO Guanghui LIU min zhang School of Electronic and Computer Engineering Peking UniversityShenzhen 518055China Shenzhen China Star Optoelectronics Technology Co. Ltd.Shenzhen 518132China

The growth direction,morphology and microstructure of carbon nano-tubes(CNTs)play key roles for their potential applications in electronic and energy storage ***,effective synthesis of CNTs in high crystallinity and desired microstructure still remains a tremendous *** we introduce an electric field for controlling the microstructure formation of *** reveals that the electric field not only make CNTs aligned parallel but also improve the density of ***,the microstructures of CNTs gradually change under electrical *** is,graphite sheets are transformed from the"herringbone"structure to a highly crystalline structure,facilitating the transportation of *** to the improved aligned growth direction,high density and highly crystalline microstructure,the electrochemical performance of CNTs is greatly *** the CNTs are applied in supercapacitors,they present a high specific capacitance of 237 F/g,three times higher than that of the CNTs prepared without electrical *** microstructure modulation of CNTs by electric field would help to construct high performance electronic and energy storage devices.

关键词： carbon nanotube electric field microstructure control supercapacitor electrochemical performance

Oil geochemistry derived from the Qinjiatun–Qikeshu oilfields:insight from light hydrocarbons

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Acta Geochimica 2018年第3期37卷 433-440页

作者： Jin Li Ting Kong min zhang Key Laboratory of Exploration Technology for Oil and Gas Research (Yangtze University) Ministry of Education College of Resources and Environment Yangtze University Research Institute of Petroleum Exploration and Development (Langfang Branch) PetroChina The Key Laboratory of Gas Formation and Development Petrochina

A suite of 27 oils from the Qinjiatun–Qikeshu oilfields in the Lishu Fault Depression of the Songliao Basin was analyzed using whole oil gas *** combination with the relative distribution of C27, C28,and C29 regular steranes, detailed geochemical analyses of light hydrocarbons in oil samples revealed crude oils characterized by the dual input of lower aquatic organisms and higher terrestrial plants. Several light hydrocarbon indicators suggest that the liquid hydrocarbons have maturities equivalent to vitrinite reflectances of around0.78%–0.93%. This is consistent with the maturity determination of steranes C2920 S/(20 S ? 20 R) and C29 aab/(aaa ? abb). Crude oils derived from the two distinct oilfields likely both have source rocks deposited in a lacustrine environment based on light hydrocarbon parameters and on higher molecular weight hydrocarbon parameters. The results show that light hydrocarbon data in crude oils can provide important information for understanding the geochemical characteristics of the Qinjiatun–Qikeshu oils during geologic evolution.

关键词： Light hydrocarbons Crude oil Lishu FaultDepression Geochemistry characteristic

Evaluation of gas wettability and its effects on fluid distribution and fluid flow in porous media

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Petroleum Science 2013年第4期10卷 515-527页

作者： Jiang Guancheng Li Yingying zhang min State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum MOE Key Laboratory of Petroleum Engineering China University of Petroleum

The special gas wettability phenomenon of reservoir rocks has been recognized by more and more *** has a significant effect on efficient development of unconventional ***,based on the preferentially gas-covered ability and surface free energy changes,definition and evaluation methods have been ***,a method for altering rock wettability and its mechanisms have been studied,surface oriented phenomena of functional groups with low surface energy are the fundamental reason for gas wettability alteration of ***,the effect of gas wettability on the surface energy,electrical properties and dilatability are ***,the effects of gas wettability on capillary pressure,oil/gas/water distribution and flow are investigated with capillary tubes and etchedglass network *** gas wettability theory of reservoir rocks has been initially established,which provides theoretical support for the efficient production of unconventional reservoirs and has great significance.

关键词： Gas-wetting fluorocarbon copolymer contact angle capillary pressure surface free energy surface property fluid flow in porous media

Genesis study of high abundant 17α(H)-diahopanes in Lower Cretaceous lacustrine source rocks of the Lishu Fault Depression, Songliao Basin, Northeast China

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Chinese Journal Of Geochemistry 2014年第2期33卷 201-206页

作者： LIU Haiyu zhang min LI Xing School of Earth Environment and Water Resources Yangtze University Key Laboratory of Exploration Technologies for Oil and Gas Resources Yangtze University Zhanjiang Branch of CNOOC Ltd.

Relatively abundant 17α(H)-diahopanes have been detected in the lower cretaceous lacustrine source rocks from the Lishu Fault Depression in the Songliao Basin Northeast China. Rich long chain tricyclic terpanes(carbon number up to C35) and gammacerane have been observed in those source rocks with relatively abundant 17α(H)-diahopanes, which is rarely seen in previous reports. In this paper, the formation of 17α(H)-diahopanes has been discussed from three aspects including maturity, oxidation-reduction nature of depositional environment and parent material composition by the GC/MS analyses. The results reveal that maturity and oxidation-reduction nature of depositional environment have little effect on the formation of 17α(H)-diahopanes in the investigated area. However, the positive correlation between long-chain tricyclic terpanes and 17α(H)-diahopanes argues strongly for a common origin, and the origin is related to the algaes in saline water environment. The algaes in saline water environment may be a kind of origin of 17α(H)-diahopanes.

关键词：中国东北地区湖相烃源岩重排藿烷梨树断陷松辽盆地下白垩统 A(H) 成因

ANALYSIS ON AGRICULTRUAL INFORMATION DEMAND——Case of Jilin Province

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Chinese Geographical Science 2005年第3期15卷 281-287页

作者： zhang Hui-min JIANG Hui-ming Northeast Institute of Geography and Agricultural Ecology Chinese Academy of Sciences Changchun 130012 P. R. China Managerial College Jilin Agricultural University Changchun 130118 P. R. China

With the rapid development of agricultural informalization in the world, the demand of agricultural information has been a focus in the international agriculture and information fields. Based on the investigation, this paper presented the four characteristics of the demand of agricultural information in China, includingregionality, seasonality, great potential demand and variation in kind and level. The factors infuencing the demand of agricultural information were analyzed by the Optimized Less Square （OLS） method. The result shows that, of all factors influcing agricultural information demand, the most important one is economy, the second is facility of information pass, and knowledge and education of user, credit of agricultural information service system and production situation follow. Taking Jilin Province as an example, this article also elaborated the agricultural information demand status, and deduced the regression model of agricultural information demand and verified it by the survey in rural Jilin.

关键词： agricultural information demand agricultural information service system Jilin Province

Chemical compositions of precipitation and scavenging of particles in Beijing

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Science China Chemistry 2005年第3期48卷 265-272页

作者： HU min zhang Jing WU Zhijun State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences Peking University Beijing 100871 China State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences Peking University Beijing 100871 China State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences Peking University Beijing 100871 China

Totally 23 precipitation samples were collected in Beijing from May to November in 2003. In order to investigate the chemical composition of precipitation samples, pH, conductivity, concentrations of water-soluble ions and organic acids were analyzed. The average pH of pre-cipitations is 6.18, belonging to the neutral range; the average conductivity is 52.23 μS/cm, which indicates that precipitations in Beijing are obviously polluted; SO 24? , NO3 ? are the most abundant anions with the average concentrations of 521 and 174 μeq·L?1, respectively; the average 2SO 4? /NO3? equivalent ratio is 3.1, which decreases by about 15% compared with the result of 1994; NH+ 4 and Ca2+ are the most abundant cations with the average concentrations of 376 and 397 μeq·L?1, respectively; formic acid, acetic acid and oxalic acid are the main organic acids with the average concentrations of 4.62, 4.60 and 1.17 μeq·L?1, respectively, accounting for 2% of the overall anions. Obvious differences between concentrations before and after precipitation are also observed by SJAC (Steam Jet Aerosol Collector), which shows the removal of particles from the atmosphere by precipitation.

关键词： precipitation, particles, ions, organic acids, scavenging.

A Study on CFL Conditions for the DG Solution of Conservation Laws on Adaptive Moving Meshes

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Numerical Mathematics(Theory,Methods and Applications) 2023年第1期16卷 111-139页

作者： min zhang Weizhang Huang Jianxian Qiu School of Mathematical Sciences Peking UniversityBeijing 100871China Department of Mathematics University of KansasLawrenceKansas 66045USA School of Mathematical Sciences Fujian Provincial Key Laboratory of Mathematical ModelingHigh-Performance Scientific ComputingXiamen UniversityXiamenFujian 361005China

The selection of time step plays a crucial role in improving stability and efficiency in the Discontinuous Galerkin(DG)solution of hyperbolic conservation laws on adaptive moving meshes that typically employs explicit stepping.A commonly used selection of time step is a direct extension based on Courant-Friedrichs-Levy(CFL)conditions established for fixed and uniform *** this work,we provide a mathematical justification for those time step selection strategies used in practical adaptive DG computations.A stability analysis is presented for a moving mesh DG method for linear scalar conservation *** on the analysis,a new selection strategy of the time step is proposed,which takes into consideration the coupling of theα-function(that is related to the eigenvalues of the Jacobian matrix of the flux and the mesh movement velocity)and the heights of the mesh *** analysis also suggests several stable combinations of the choices of theα-function in the numerical scheme and in the time step *** results obtained with a moving mesh DG method for Burgers’and Euler equations are *** comparison purpose,numerical results obtained with an error-based time step-size selection strategy are also given。

关键词： Discontinuous Galerkin method adaptive mesh moving mesh CFL condition stability

Molecular geochemical characteristics of source rock in faulted lacustrine basin:A case study of the Lishu Fault Depression in southern Songliao Basin,China

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Chinese Journal Of Geochemistry 2013年第4期32卷 413-419页

作者： LI Hongbo zhang min CHEN Xiaohui Department of Geochemistry Yangtze University Key Laboratory of Exploration Technologies for Oil and Gas Resources Ministry of EducationYangtze University

Terrestrial faulted lacustrine basin is considered as a favorable place for the development of source rocks,especially the fault basins in eastern *** on molecular composition study of saturated and aromatic hydrocarbons in the extracts of source rocks of the Yingcheng and Shahezi formations in the Lishu Fault Depression,it is revealed that the extracts of source rocks are provided with low ratio of Pr/Ph,low content of C24 tetracyclic terpanes,high content of tricyclic terpanes and gammacerane,relatively high content of C27 steranes in the sag belt and its periphery;relatively high ratio of Pr/Ph,relatively high content of tetracyclic terpanes and gammacerane,low content of C27 steranes and obvious advantages of C29 steranes in its gentle slope belt;with high ratio of Pr/Ph,high content of C19,C20 tricyclic and C24 tetracyclic terpanes,very low content of gammacerane and C27 steranes,and high content of C29 steranes in the edge of fault *** to the organic matter input and sedimentary environment,three types of source rocks have been established,which,respectively,are the mode of mixing organic matter input in deep and semi-deep lake,the advantage of terrigenous input in shallow lake and terrigenous input in shore-shallow *** first mode is supposed to generate oil and gas,while the second one tends to generate *** distribution characteristics of oil and gas in the Lishu Fault Depression are very likely to be controlled by hydrocarbon generating characteristic of different source rock types.

关键词：梨树断陷断陷湖盆中国东部分子组成烃源岩松辽盆地南部地球化学特征伽马蜡烷

Master equation approach to transient quantum transport in nanostructures

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Frontiers of physics 2017年第4期12卷 43-78页

作者： Pei-Yun Yang Wei-min zhang Department of Physics and Centre for Quantum Information Science Cheng Kung University Tainan 70101

In this review article, we present a non-equilibrium quantum transport theory for transient electron dynamics in nanodevices based on exact Master equation derived with the path integral method in the fermion coherent-state representation. Applying the exact Master equation to nanodevices, we also establish the connection of the reduced density matrix and the transient quantum transport current with the Keldysh nonequilibrium Green functions. The theory enables us to study transient quantum transport in nanostructures with back-reaction effects from the contacts, with non-Markovian dissipa- tion and decoherence being fully taken into account. In applications, we utilize the theory to specific quantum transport systems, a variety of quantum decoherence and quantum transport phenomena involving the non-Markovian memory effect are investigated in both transient and stationary scenarios at arbitrary initial temperatures of the contacts.

关键词： quantum transport Master equation open systems nanostructures