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Cluster and characteristic analysis of Shanghai metro stations based on metro card and land-use data

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Geo-Spatial Information Science 2020年第4期23卷 352-361页

作者： ping shen Linxin Ouyang Chong Wang Yin Shi Yiheng Su Guangzhou Urban Planning&Design Survey Research Institute GuangzhouChina Shanghai Tongji Urban Planning&Design Institute Co. Ltd.ShanghaiChina Tongji Architectural Design(Group)Co. Ltd.ShanghaiChina Shanghai Urban Planning and Design Research Institute ShanghaiChina

Metro is an important form of public transport in *** on the metro card data,we conduct the cluster analysis of Shanghai metro stations according to the pattern of passenger flow changing with *** the characteristics of travel time and surrounding land use are investigated for different types of stations to explore the relationship between urban land-use characteristics and travel activities reflected by passenger flow at metro *** is found that the passenger flow pattern of metro stations is closely related to the location conditions of stations and its surrounding land-use *** on various characteristics,285 metro stations are classified into four types,including residential-oriented stations,employmentoriented stations,employment-residence-oriented stations,and integrated functionaloriented stations,reflecting the interaction between spontaneous travel behavior and urban land-use characteristics and providing a reference for optimizing the urban functional structure and the spatial allocation of facilities.

关键词： Metro stations travel behavior pattern metro card data land use

Fully Distributed AC State Estimation Method for Power System Based on Information Propagation Algorithm

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Journal of Modern Power Systems and Clean Energy 2023年第4期11卷 1201-1211页

作者： Qiao Li Yu shen Lin cheng David Wenzhong Gao University of Denver 2155 E Wesley AveDenverCO 80210USA Tsinghua University BeijingChina

This paper proposes a new distributed AC state estimation *** from the popular distributed state estimation(DSE)methods based on area partitioning method,the proposed method is a truly distributed method in which the power system is not required to be divided into smaller areas and a centralized state estimator in each area is not *** order to achieve fully DSE,the information propagation algorithm is introduced in this paper to help the distributed local state estimators share the measurement *** information propagation algorithm is developed based on consensus *** proof of the convergence of the information propagation algorithm is provided in this ***,the AC state estimation method is integrated with the information propagation algorithm to realize the proposed *** proposed method is tested in different standard power system *** results show that the proposed method reaches the similar accuracy as the traditional centralized state estimation methods and performs faster and more accurate than the existing DSE methods.

关键词： State estimation consensus protocol distributed network graph theory

Improved oxidation of hydrogen off-gas by hydrophobic surface modification: A multiscale density functional theory study

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Particuology 2019年第3期17卷 28-35页

作者： cheng Lian cheng Cai Xiangjian shen Shuangliang Zhao Xinhai Yu Honglai Liu State Key Laboratory of Chemical Engineering and School of Chemical Engineering East China University of Science and Technology Shanghai 200237 China School of Chemistry and Molecular Engineering East China University of Science and Technology Shanghai 220237 China Research Center of Heterogeneous Catalysis and Engineering Science School of Chemical Engineering and Energy Zhengzhou University Zhengzhou 450001 China Key Laboratory of Safety Science of Pressurized System (MOE) School of Mechanical Engineering East China University of Science and Technology Shanghai 200237 China

A catalytic micro-reactor for converting hydrogen off-gas into water was recently developed, through which the conversion efficiency of hydrogen gas was greatly improved by hydrophobic modification of the catalytic substrate. Herein, a hybrid theoretical method is reported that combines density functional theory (DFT) on both the quantum and molecular scales. This method allows the microscopic study of the mechanism by which the surface catalytic reaction can be manipulated. Specifically, quantum DFT calculations are performed to quantify the molecular interaction between the catalytic substrate and reagent or product. Classical DFT investigations are subsequently carried out to determine the local concentrations of reagents near catalytic sites subject to different surface coating conditions. Finally, the reaction efficiency is determined from the local concentrations based on collision theory. This multiscale method provides molecular insight for quantifying the effect of catalytic surface modification on the reaction efficiency. The method reveals that an optimal surface hydrophobic modification can promote the densities of reagents near the substrate, while depleting the produced water. These two factors promote the conversion efficiency. The exclusion of produced water from the catalytic substrate is affected more by the degree of polymer grafting than by the chain length of hydrophobic polymer moieties.

关键词： Surface reaction Hydrophobic modification Density functional theory Multiscale

INTEGRATIVE CAD/ CAE/ CAM FOR COMPLICATED PANEL METAL STAMping OF OIL PAN USED IN THE CAR ENGINE

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Acta Mechanica Solida Sinica 2001年第3期14卷 259-267页

作者： Hu ping shen Guozhe Liu Yuai Jilin Univ Inst Automobile Panel Forming Tech Changchun 130025 Peoples R China

The oil pan used in car engine is one of the important structureparts in the car, which is, in general, deep drawn and difficult toform. The deep-drawing processes of the oil pan used in the enginefor 'Small Flag' Car of the First Automobile Manufactory is analyzedby using the integrative CAD/CAE/CAM technique of stamping die,including the CAD software CATIA and the sheet-metal stamping CAEsoftware KMAS developed independently.

关键词： oil pan CATIA sheet-metal stamping

Effect of Si/Si_(1-y)C_(y)/Si Barriers on the Characteristics of Sil-xGex/Si Resonant Tunneling Structures

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Chinese Physics Letters 2000年第11期17卷 844-846页

作者： HAN ping cheng Xue-Mei Department of Physics Nanjing UniversityNanjing 210093 Masao SakurabaYoung-Cheon JeongTakashi MatsuuraJunichi Murota Research Institute of Electrical CommunicationTohoku University 2-1-1 KatahiraAoba-kuSendai 980-8577Japan

P-type double barrier resonant tunneling diodes (RTD) with the single Si0.6Ge0.4 quantum well and double Si0.6Ge0.4spacer have been realized by using an ultra clean low-pressure chemical vapor deposition system. The effect of Si_(1-y)C_(y) layer on the characteristics of the devices was shown by comparing the current-voltage (I-V) characteristics of RTD’s of the barriers of Si layers with that of Si/ Si_(1-y)C_(y)/Si structures. The peak voltage was gradually increased and the resonant current decreased obviously with increasing C content in the Si/ Si_(1-y)C_(y)/Si barriers. The origin of the phenomena above can be attributed to the C related deep acceptor levels in the Si/ Si_(1-y)C_(y)/Si barriers. The possible mechanism for the observed I- V characteristics was shown more clearly by increasing C content to 3% and changing the thicknesses of Si and Si_(1-y)C_(y) layers in the Si/Si_(1-y)C_(y)/Si barriers.

关键词： Si/Si resonant Tunnel

Investigating the neutron star physics through observations of several young pulsars in the dipole-field re-emergence scenario

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Science China(Physics,Mechanics & Astronomy) 2024年第12期67卷 197-208页

作者： Yu-Long Yan Quan cheng Xiao-ping Zheng Institute of Astrophysics Central China Normal UniversityWuhan430079China Department of Astronomy Huazhong University of Science and TechnologyWuhan430074China

The observed timing data,magnetic tilt angle χ,and age of young pulsars could be used to probe some important issues about neutron star(NS) physics,e.g.,the NS internal magnetic field configuration,and the number of precession cycles ξ.Both quantities are critical in studying the continuous gravitational wave emission from pulsars,and the latter generally characterizes the mutual interactions between superfluid neutrons and other particles in the NS *** timing behavior of pulsars can be influenced by the dipole field evolution,which instead of decaying,may increase with *** increase in the dipole field may result from the re-emergence of the initial dipole field B_(d,i)that was buried into the NS interior shortly after the birth of the *** this work,the field re-emergence scenario ξ and the internal field configuration of several young pulsars,as well as their B_(d,i) are investigated by assuming typical accreted masses ?***,since the Crab pulsar has an exactly known age and its tilt angle change rate can be inferred from observations,we can set stringent constraints on its ξ,B_(d,i),and ?*** for other young pulsars without exactly known ages and tilt angle change rates,these quantities cannot be accurately determined,we find that their ξ are generally within ~10~4-10~6,and some of them probably have magnetar-strength B_(d,i).Our work could be important for investigating the transient emissions associated with NSs,the origin of strong magnetic fields of NSs,pulsar population,continuous gravitational wave emission from pulsars,and accretion under extreme conditions in principle.

关键词： pulsar neutron star magnetic field

In vivo label-free measurement of blood flow velocity symmetry based on dual line scanning third-harmonic generation microscopy excited at the 1700 nm window

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Journal of Innovative Optical Health Sciences 2024年第1期17卷 61-68页

作者： Hui cheng Jincheng Zhong ping Qiu Ke Wang Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic Engineering shenzhen University Shenzhen 518060 P.R.China

Measurement of bloodflow velocity is key to understanding physiology and pathology in *** most measurements are performed at the middle of the blood vessel,little research has been done on characterizing the instantaneous bloodflow velocity *** is mainly due to the lack of measurement technology with high spatial and temporal ***,we tackle this problem with our recently developed dual-wavelength line-scan third-harmonic generation(THG)imaging *** acquisition of dual-wavelength THG line-scanning signals enables measurement of bloodflow velocities at two radially symmetric positions in both venules and arterioles in mouse brain in *** results clearly show that the instantaneous bloodflow velocity is not symmetric under general conditions.

关键词： 1700 nm-Window third-harmonic generation imaging blood flow velocity

General explicit solutions of most economic sections and applications for trapezoidal and parabolic channels

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Journal of Hydrodynamics 2019年第5期31卷 1034-1042页

作者： Yan-cheng Han Said MEasa Xue-ping Gao School of Water Conservancy and Environment University of JinanJinan 250022China Department of Civil Engineering Ryerson UniversityTorontoOntarioCanada State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

A channel section that has minimum construction cost is known as the most economic *** a section has important implications for economic ***,the most economic section is a complex optimization model with nonlinear objective function and constraints that is difficult to use by ordinary engineers.A general simple formula for the most economic section has not been *** this paper,the general differential equation for the most economic section is derived using Lagrange multiplier optimization method.A simple method to solve the most economic section is proposed that converted the optimization model into a general equation for the most economic section of any *** solving this equation,the dimensions of the most economic section are directly *** illustrate,the direct formula for trapezoidal section is *** aid application in practice,a simple explicit iterative formula for trapezoidal sections is *** direct and explicit iterative formulas were *** proposed method is superior to the classical optimization method and as such represent a valuable tool for open channel *** illustrate the versatility of the presented method,a direct formula for the parabolic section was also derived.

关键词： Most economic section channel parabolic explicit hydraulic section

Microstructure of Electrodeposited Cu Micro-cylinders in High-Aspect-Ratio Blind Holes and Crystallographic Texture of the Cu Overburden Film

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Journal of Materials Science & Technology 2016年第4期32卷 355-361页

作者： Yazhou Zhang Guifu Ding Hong Wang ping cheng National Key Laboratory of Science and Technology on Micro/Nano Fabrication Department of Micro/Nano Electronics School of Electronic Informationand Electrical Engineering Shanghai Jiao Tong University Shanghai 200240 China

Microstructure and texture of electrodeposited Cu micro-cylinders in the blind hole play a vitally im- portant role in the electrical and mechanical properties of the three-dimensional （3-D） IC （integrated circuit）/Si integrations. In this paper, a new commercial additive system, which is specifically devel- oped for the high-aspect-ratio through-silicon-via （TSV） filling, was used to electrodeposit Cu in the blind holes. The microstructure of electrodeposited Cu micro-cylinder in the blind hole with a diameter of 40 μm and a depth of 140 μm was investigated by electron back-scattered diffraction （EBSD） technique. Grain size distribution of the Cu micro-cylinder in the blind hole differed from the bottom to the top. The grain boundaries contained a high fraction of Z3 CSL （coincident site lattice） boundaries. It has been reported that the Cu overburden film on the surface of the blind hole influenced the crystallographic orientation of Cu grains inside the damascene trench. So the effects of the current density and additive concentra- tion on the crystal structure of the overburden Cu film were also studied in this study. The experimental results indicated that the preferred orientation of the Cu overburden film changed from {111} to {220} when the current density increased from 2 to 80 mA cm-2. However, the effect of additives on the crystal structure of the Cu overburden film was dependent on the crystal structure of the seed layer.

关键词： Cu micro-cylinder electrodepositionElectron back-scattered diffraction (EBSD)Crystallographic orientationCu overburden film