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Evaluating spatial accessibility to healthcare services from the lens of emergency hospital visits based on floating car data

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International Journal of Digital Earth 2022年第1期15卷 108-133页

作者： wei jiao wei Huang Hongchao Fan School of Remote Sensing and Information Engineering Wuhan UniversityWuhanPeople’s Republic of China College of Surveying and Geo-Informatics Tongji UniversityShanghaiPeople’s Republic of China Department of Civil Engineering Ryerson UniversityTorontoCanada Department of Civil and Environmental Engineering Norwegian University of Science and TechnologyTrondheimNorway

Public medical facilities that are closely related to the health of residents have been recognised as one of the most crucial elements in sustainable urban *** the sake of social equality of medical services(especially for emergency medical conditions),the spatial distributions of medical resources need to be accurately measured and continuously *** study presents an effective method to examine night emergency hospital visit and analyse its spatiotemporal characteristics using float car data(FCD).By extracting the hospital service areas,the two-step floating catchment area(2SFCA)methodology was improved to calculate hospital ***,the balance between hospital accessibility and population density was *** addition,we investigated the relationship between individual hospital choice preferences and hospital level and analysed several factors that affect individual *** results help us understand the special requirements and need of emergency hospital travel in cities and identify areas where medical resources are *** can be used as guidance for urban hospital planning and *** the approach of hospital access behaviour investigation and the improved 2SFCA method can also provide insights for other activity-based travel behaviour research.

关键词： Floating car data hospital emergency travels hospital service areas hospital accessibility

Multi-bright-dark soliton solutions to the AB system in nonlinear optics

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Communications in Theoretical Physics 2022年第4期74卷 23-30页

作者： Yunyun Zhai Lifei wei Xianguo Geng jiao wei School of Mathematics and Statistics Zhengzhou University100 Kexue RoadZhengzhouHenan 450001China

The AB system is the basic integrable model to describe unstable baroclinic wave packets in geophysical fluids and the propagation of mesoscale gravity flows in nonlinear optics. On the basis of the spectral analysis of a Lax pair and the inverse scattering method, we establish the Riemann–Hilbert problem of the AB system. Then, the inverse problems are formulated and solved with the aid of the Riemann–Hilbert problem, from which the potentials can be reconstructed according to the asymptotic expansion of the sectional analytic function and the related symmetry relations. As an application, we obtain the multi-bright-dark soliton solutions to the AB system in the reflectionless case and discuss the dynamic behavior of elastic soliton collisions by choosing appropriate free parameters.

关键词： AB system multi-soliton structures Riemann-Hilbert problem

Two-Level Linear Relaxation Method for Generalized Linear Fractional Programming

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Journal of the Operations Research Society of China 2023年第3期11卷 569-594页

作者： Hong-wei jiao You-Lin Shang Postdoctoral Research Base Henan Institute of Science and TechnologyXinxiang453003HenanChina Postdoctoral Research Station of Control Science and Engineering Henan University of Science and TechnologyLuoyang471023HenanChina

This paper presents an efficient algorithm for globally solving a generalized linear fractional programming *** establishing this algorithm,we firstly construct a two-level linear relaxation method,and by utilizing the method,we can convert the initial generalized linear fractional programming problem and its subproblems into a series of linear programming relaxation *** on the branch-and-bound framework and linear programming relaxation problems,a branch-and-bound algorithm is presented for globally solving the generalized linear fractional programming problem,and the computational complexity of the algorithm is ***,numerical experimental results demonstrate the feasibility and efficiency of the proposed algorithm.

关键词： Generalized linear fractional programming Global optimization Two-level linear relaxation method Branch-and-bound

Constitutive modeling and analysis on high-temperature flow behavior of 25 steel

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Journal of Iron and Steel Research International 2021年第1期28卷 76-85页

作者： wei wei Chao-long Yuan Ren-dong Wu wei jiao Ding-chuan Liang Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China

The constitutive relationship is the basis for studying the material processing technology and controlling the quality of *** and models of the plastic flow behavior of materials are often required during the manufacturing ***,establishing constitutive models with high precision and generalization and enriching material database is of great significance for optimizing processing technology and product quality of the *** on the Gleeble thermal compression test results,the essential relationship of 25 steel between the flow stress and thermal–mechanical state variables,such as temperature,strain rate,and strain,is quantitatively discussed for the first *** with the Zener–Hollomon parameter and considering the influence of strain compensation,the constitutive model of 25 steel is built by the hyperbolic-sine equation over the full strain *** the modeling process,the influence of strain on material constants is characterized by polynomial *** selection basis of polynomial order is discussed in-depth,and the inconsistency between calculation accuracy and fitting effect is ***,the accuracy of the model is analyzed,and the generalization and applicability are *** is proved that the developed model can accurately predict the flow behavior of materials in the full strain range.

关键词： Constitutive relationship Flow behavior Plastic deformation Polynomial fitting Generalization

An optimal rigidity theorem for complete submanifolds in a sphere

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Applied Mathematics(A Journal of Chinese Universities) 2008年第2期23卷 219-226页

作者： XU Hong-wei ZHU jiao-feng Center of Math. Sci. Zhejiang Univ. Hangzhou 310027 China

It is proved that if M^n is an n-dimensional complete submanifold with parallel mean curvature vector and flat normal bundle in S^n＋p（1）, and if supM S 〈 α（n, H）, where α（n,H）=n＋n^3/2（n-1）H^2-n（n-2）/n（n-1）√n^2H^4＋4（n-1）H^2,then M^n must be the totally urnbilical sphere S^n（1/√1＋H^2）.An example to show that the pinching constant α（n, H） appears optimal is given.

关键词： submanifold rigidity flat normal bundle mean curvature.

On Permutation Polynomials in Two Variables over ■/p^2■

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Acta Mathematica Sinica,English Series 2009年第7期25卷 1191-1200页

作者： Qi jiao wei Qi Fan ZHANG College of Mathematics Sichuan University Chengdu 610064 P. R. China Chengdu University of Information Technology Chengdu 610059 P. R. China

We give a good characterization of the permutation polynomials in two variables over Z/p2Z.

关键词： permutation polynomial Witt polynomial Witt vector ring

Parameter-driven Level of Detail Derivation Method for Semantic Building Facade Model

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Journal of Geodesy and Geoinformation Science 2024年第3期7卷 57-75页

作者： WANG Yuefeng jiao wei Guangxi Key Laboratory of Spatial Information and Geomatics Guilin University of TechnologyGuilin 541004China College of Geomatics and Geoinformation Guilin University of TechnologyGuilin 541004China College of Environment and Resources Guangxi Normal UniversityGuilin 541006China

The relentless progress in the research of geographic spatial data models and their application scenarios is propelling an unprecedented rich Level of Detail(LoD)in realistic 3D representation and smart *** pursuit of rich details not only adds complexity to entity models but also poses significant computational challenges for model visualization and 3D *** paper introduces a novel method for deriving multi-LOD models,which can enhance the efficiency of spatial computing in complex 3D building ***,we extract multiple facades from a 3D building model(LoD3)and convert them into individual semantic facade *** the utilization of the developed facade layout graph,each semantic facade model is then transformed into a parametric ***,we explore the specification of geometric and semantic details in building facades and define three different LODs for facades,offering a unique ***,an innovative heuristic method is introduced to simplify the parameterized *** rigorous experimentation and evaluation,the effectiveness of the proposed parameterization methodology in capturing complex geometric details,semantic richness,and topological relationships of 3D building models is demonstrated.

关键词： 3D building model multi-Level of Detail(LoD) semantic facade model CityGML 3D GIS

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A method for evaluating paleo hydrocarbon pools and predicting secondary reservoirs:a case study of the Sangonghe Formation in the Mosuowan area,Junggar Basin

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Petroleum Science 2018年第2期15卷 252-269页

作者： wei-jiao Ma Yan-Zhao wei Shi-Zhen Tao School of Earth and Space Sciences Peking UniversityBeijing 100871China Research Institute of Petroleum Exploration and Development Beijing 100083China

Taking the Jurassic Sangonghe Formation in the Mosuowan-Mobei area of the Junggar Basin as an example, this paper provides a method that evaluates paleo hydrocarbon pools and predicts secondary reservoirs. Through Quantitative Grain Fluorescence （QGF） experiments, well-tie seismic correlation, and paleo structure analysis, the scale and distribution of paleo hydrocarbon pools in the study area are outlined. Combining current structural features and fault characteristics, the re-migration pathways of paleo oil and gas are depicted. Based on barrier conditions on the oil re-migration pathways and current reservoir distribution, we recognize three types of secondary reservoirs. By analyzing structural evolution and sand body-fault distribution, the major control factors of secondary reservoirs are specified and, consequently, favorable zones for secondary reservoirs are predicted. The results are mainly as follows. （1） In the primary accumulation period in the Cretaceous, paleo hydrocarbon pools were formed in the Sangonghe Formation of the Mosuowan uplift and their size and distribution were extensive and the exploration potential for secondary reservoirs should not be ignored. Besides, paleo reservoirs were also formed in the Mobei uplift, but just small scale. （2） In the adjustment period in the Neogene, traps were reshaped or destroyed and so were the paleo reservoirs, resulting in oil release. The released oil migrated linearly northward along the structural highs of the Mobei uplift and the Qianshao low-relief uplift and then formed secondary reservoirs when it met new traps. In this process, a structural ridge cooperated with sand bodies and faults, applying unobstructed pathways for oil and gas re-migration. （3） The secondary hydrocarbon pools are classified into three types： low-relief anticlinal type, lithologic pinch-out type and fault block type. The distribution of the first type is controlled by a residual low uplift in the north flank of the paleo-anticl

关键词： Junggar Basin Paleo hydrocarbon pools Hydrocarbon re-migration pathways Secondary reservoirs .Favorable zones

The hydraulic performance of twin-screw pump

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Journal of Hydrodynamics 2020年第3期32卷 605-615页

作者： Di Zhang Li Cheng Ying-yuan Li wei-xuan jiao School of Hydraulic Energy and Power EngineeringYangzhou UniversityYangzhou 225009China

Based on the computational fluid dynamics (CFD) and the experiment technology, this paper presents a new type of the twin-screw pump for the water-supply and studies its hydraulic performance with the hydraulic performance test. The internal flow characteristics and the hydraulic performance of the twin-screw pump are numerically simulated. The CFD results show that at different heads, the screw pressure gradually increases from the inlet end face along the axial direction of the screw to the outlet end face. The pressure distribution in the screw groove is relatively uniform, the screw clearance and the meshing area pressure are different from the screw groove pressure distribution. Under the same working condition of the head, the pressure distributions in the screw below and above the design speed are the same as the pressure distribution at the design speed, and with the range of the pressure value quite close. As the rotating speed increases furthermore, the flow rate and the volume efficiency of the pump both increase. At different rotating speeds, the velocity distributions along the axial direction of the screw are similar. A test rig is built, which consists of a closed-loop circuit, and the test results are found in good agreement with the CFD predictions. The experimental results show that the flow rate-head curves of the twin-screw pumps are similar at different rotating speeds. The research shows that the designed twin-screw pump enjoys a higher volumetric efficiency and a lower shaft power when the axial clearance is 0.08 mm-0.12 mm. When the clearance is 0.1 mm, the volumetric efficiency is the highest.

关键词： Twin-screw pump screw-rotor profile hydraulic characteristics screw clearances