期刊文献+
共找到1,730篇文章
< 1 2 87 >
每页显示 20 50 100
Spatial Morphology Evolution Characteristics Analysis of the Resident Population Distribution in Henan, China
1
作者 Kaiguang Zhang Hongling Meng +1 位作者 Mingting Ba Danhuan Wen 《Journal of Geoscience and Environment Protection》 2024年第3期163-180,共18页
The population spatial distribution pattern and its evolving pattern play an important role in regional allocation of social resources and production factors, formulation of regional development plans, construction of... The population spatial distribution pattern and its evolving pattern play an important role in regional allocation of social resources and production factors, formulation of regional development plans, construction of a better life society, and promotion of regional economic development. Based on the resident population statistics data of Henan province from 2006 to 2021, with county as the basic study unit, the paper studies the spatial morphology characteristics and its evolution patterns of resident population distribution, by using spatial analysis methods such as population distribution center, standard deviation ellipse, and spatial auto correlation analysis. The results show that: the resident population spatial distribution shows unbalanced state, the population agglomeration areas mainly distribute in the northeast part and north part, where the resident population growth rate is significantly higher than other regions, over time, this trend is gradually becoming significant. The resident population distribution has a trend of centripetal concentration, with the degree and trend of centripetal gradually strengthening. The resident population distribution has obvious directional characteristics, but the significance is not high, the weighted resident population average center is approximately located at (4.13740˚N, 113.8935˚E), and the azimuth of the distribution axis is approximately 11.19˚. The population distribution has obvious agglomeration characteristics, with the built-up areas of Zhengzhou and Luoyang as their centers, where have a significant siphon effect on the surrounding population. The southern and southwestern regions in the province form a relatively stable belt area of Low-Low agglomeration areas. 展开更多
关键词 Resident Population Spatial distribution Spatial Morphology Temporal and Spatial evolution Center Migration Standard Deviation Ellipse Spatial Autocorrelation
下载PDF
Probability Distribution of China Aviation Network Average Degree of Edge Vertices and Its Evolutionary Trace Based on Complex Network
2
作者 Cheng Xiangjun Zhang Chunyue Liang Yanping 《Journal of Traffic and Transportation Engineering》 2024年第2期51-62,共12页
In order to reveal the complex network characteristics and evolution principle of China aviation network, the probability distribution and evolution trace of average degree of edge vertices of China aviation network w... In order to reveal the complex network characteristics and evolution principle of China aviation network, the probability distribution and evolution trace of average degree of edge vertices of China aviation network were studied based on the statistics data of China civil aviation network in 1988, 1994, 2001, 2008 and 2015. According to the theory and method of complex network, the network system was constructed with the city where the airport was located as the network node and the route between cities as the edge of the network. Based on the statistical data, the average degrees of edge vertices in China aviation network in 1988, 1994, 2001, 2008 and 2015 were calculated. Using the probability statistical analysis method and regression analysis approach, it was found that the average degree of edge vertices had the probability distribution of normal function and the position parameters and scale parameters of the probability distribution had linear evolution trace. 展开更多
关键词 Complex network China aviation network average degree of edge vertices normal distribution linear evolution trace
下载PDF
Probability Distribution of Ratio of China Aviation Network Edge Vertices Degree and Its Evolutionary Trace Based on Complex Network
3
作者 Cheng Xiangjun Yang Fang Wei Liying 《Journal of Traffic and Transportation Engineering》 2024年第3期119-129,共11页
In order to reveal the complex network characteristics and evolution principle of China aviation network, the probability distribution and evolution trace of ratio of China aviation network edge vertices degree were s... In order to reveal the complex network characteristics and evolution principle of China aviation network, the probability distribution and evolution trace of ratio of China aviation network edge vertices degree were studied based on the statistics data of China civil aviation network in 1988, 1994, 2001, 2008 and 2015. According to the theory and method of complex network, the network system was constructed with the city where the airport was located as the network node and the route between cities as the edge of the network. Based on the statistical data, the ratio of edge vertices degree in China aviation network in 1988, 1994, 2001, 2008 and 2015 were calculated. Using the probability statistical analysis method and regression analysis approach, it was found that the ratio of edge vertices degree had linear probability distribution and the two parameters of the probability distribution had linear evolution trace. 展开更多
关键词 Complex network China aviation network ratio of edge vertices degree linear probability distribution linear evolution trace.
下载PDF
Probability Distribution of China Aviation Network Nearest Neighbor Average Degree and Its Evolutionary Trace Based on Complex Network
4
作者 Cheng Xiangjun Zhang Chunyue Guo Jianyuan 《Journal of Traffic and Transportation Engineering》 2023年第3期95-106,共12页
In order to reveal the complex network characteristics and evolution principle of China aviation network,the probability distribution and evolution trace of node nearest neighbor average degree of China aviation netwo... In order to reveal the complex network characteristics and evolution principle of China aviation network,the probability distribution and evolution trace of node nearest neighbor average degree of China aviation network were studied based on the statistics data of China civil aviation network in 1988,1994,2001,2008 and 2015.According to the theory and method of complex network,the network system was constructed with the city where the airport was located as the network node and the route between cities as the edge of the network.Based on the statistical data,the nearest neighbor average degrees of nodes in China aviation network in 1988,1994,2001,2008 and 2015 were calculated.Using the probability statistical analysis method,it was found that the nearest neighbor average degree had the probability distribution of normal function and the position parameters and scale parameters of the probability distribution had linear evolution trace. 展开更多
关键词 Complex network China aviation network nearest neighbor average degree normal probability distribution linear evolution trace
下载PDF
Improved Hybrid Differential Evolution-Estimation of Distribution Algorithm with Feasibility Rules for NLP/MINLP Engineering Optimization Problems 被引量:4
5
作者 摆亮 王钧炎 +1 位作者 江永亨 黄德先 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2012年第6期1074-1080,共7页
In this paper, an improved hybrid differential evolution-estimation of distribution algorithm (IHDE-EDA) is proposed for nonlinear programming (NLP) and mixed integer nonlinear programming (MINLP) models in engineerin... In this paper, an improved hybrid differential evolution-estimation of distribution algorithm (IHDE-EDA) is proposed for nonlinear programming (NLP) and mixed integer nonlinear programming (MINLP) models in engineering optimization fields. In order to improve the global searching ability and convergence speed, IHDE-EDA takes full advantage of differential information and global statistical information extracted respectively from differential evolution algorithm and annealing mechanism-embedded estimation of distribution algorithm. Moreover, the feasibility rules are used to handle constraints, which do not require additional parameters and can guide the population to the feasible region quickly. The effectiveness of hybridization mechanism of IHDE-EDA is first discussed, and then simulation and comparison based on three benchmark problems demonstrate the efficiency, accuracy and robustness of IHDE-EDA. Finally, optimization on an industrial-size scheduling of two-pipeline crude oil blending problem shows the practical applicability of IHDE-EDA. 展开更多
关键词 differential evolution estimation of distribution hybrid evolution mixed-coding feasibility rules
下载PDF
City Size Distribution and Its Spatiotemporal Evolution in China 被引量:4
6
作者 SHI Lifeng ZHANG Zengxiang +8 位作者 LIU Fang ZHAO Xiaoli WANG Xiao LIU Bin HU Shunguang WEN Qingke ZUO Lijun YI Ling XU Jinyong 《Chinese Geographical Science》 SCIE CSCD 2016年第6期703-714,共12页
Based on the National Land Use/Cover Database of China(NLUD-C) in the end of the 1980s(the 1980s,hereafter), 1995, 2000, 2005, and 2010, 665 cities were selected to study the size distribution and its changes of urban... Based on the National Land Use/Cover Database of China(NLUD-C) in the end of the 1980s(the 1980s,hereafter), 1995, 2000, 2005, and 2010, 665 cities were selected to study the size distribution and its changes of urban lands in China. In this study, the spatiotemporal evolutions of urban land size distribution as well as the influence of administrative-level on these cities were explored by combining urban spatial positions and administrative-levels. Results indicate that: 1) City size distribution using urban lands was more practical and reasonable than using non-agricultural population. 2) In the 1980s, cities with ascending urban land rank were centralized in Eastern China, specially the Changjiang(Yangtze) River Delta, the Zhujiang(Pearl) River Delta, and Beijing-Tianjin-Hebei region. Cities in Central, Western, and Northeast China mainly indicated descending urban land rank. 3) The transfer of national development focus resulted in cities with ascending urban land rank becoming evenly distributed nationwide; however, this trend was slightly centralized around Chengdu, Chongqing, and Wuhan in different periods. 4) During the 1980s to 2010, the proportion of cities with ascending urban land rank in provincial capitals, municipalities, and special administrative regions(high-level cities, hereafter) was consistently higher than those in prefecture- and county-level cities except for 2005–2010. The ranks of the majority of the prefecture- and county-level cities were mainly descending, supported by ascending; the proportion of cities with unchanged rank is small. This study breaks through the bottleneck of traditional research in the area of city size distribution by examining urban land replacing the non-agricultural population. The current study also provides scientific explanation for the healthy and reasonable development of urban land as well as the coordinated development of population urbanization and land urbanization. 展开更多
关键词 Chinese city urban land size distribution spatiotemporal evolution remote sensing
下载PDF
An Improved Differential Evolution Whale Algorithm for Economic Load Distribution
7
作者 Haiming Li Chunning Fu 《Journal of Computer and Communications》 2022年第10期88-103,共16页
An improved optimization algorithm combining the differential evolution algorithm and the whale algorithm is proposed for the problem of not being able to get rid of the local optimum in the economic load distribution... An improved optimization algorithm combining the differential evolution algorithm and the whale algorithm is proposed for the problem of not being able to get rid of the local optimum in the economic load distribution algorithm. The algorithm adopts a nonlinear convergence strategy, a crossover strategy of differential evolution and the introduction of an elimination mechanism, which balances the global search and local exploitation ability of the algorithm and improves the accuracy of the solved optimal solution. The 13-unit and 40-unit systems are selected for economic load distribution calculation, and the experimental results show that the proposed improved algorithm is superior in distributing the economic load of the power system and can effectively reduce the economic cost. 展开更多
关键词 Whale Optimization Algorithm Differential evolution Algorithm Elimination Mechanism Economic Load distribution
下载PDF
Spatial Distribution and Tectonic Evolution of Ultrahigh-P(UHP) and High-P(HP) Metamorphic Belts in Central and Eastern China
8
作者 J.G.Liou W.G.Ernst +7 位作者 Xiaomin WANG Ruyuan ZHANG E.Eide Jun LIU S.Maruyama Leslie Ames Gaozhi ZHOU Yuanjun LIU 《资源环境与工程》 2016年第B04期76-88,共13页
关键词 UHP Spatial distribution and Tectonic evolution of Ultrahigh-P and High-P HP Metamorphic Belts in Central and Eastern China
下载PDF
Sediment distribution characteristics and environment evolution within 100 years in western Laizhou Bay,Bohai Sea,China 被引量:4
9
作者 Mao-sheng Gao Guo-hua Hou +1 位作者 Xian-zhang Dang Xue-yong Huang 《China Geology》 2020年第3期445-454,共10页
This study is about the reconstruction of fluvial origins based on the grain size distribution of sediment deposits in the western Laizhou Bay,Bohai Sea,China.Thirteen sediment cores were selected to research sediment... This study is about the reconstruction of fluvial origins based on the grain size distribution of sediment deposits in the western Laizhou Bay,Bohai Sea,China.Thirteen sediment cores were selected to research sediment characteristics using the Sahu discriminant formula,C-M diagram,and Folk method.The results showed:(1)Bounded by the Guangli River estuary,the north sediment was affected by the water and sand flowing from the Yellow River during different periods.The south sediment came from multi-source rivers under the influence of the Xiaoqing River,Mihe River,and other coastal rivers;(2)the deposited sediments were dated by a clear historical record of the branched channel oscillation combined with the characteristics of the diversion channel,erosion,and regression.The subaqueous delta overlapped during several Yellow River channel runs(1897–1904,1929–1934,1938–1947,1947–1953,1976–1996)and the deposited sediment facies changed(the north tidal flat-abandoned subaqueous delta-lateral delta-delta front);(3)the deposited sediment characteristics can be revealed by studying the branched diversions of the Yellow River and coastal multi-rivers of the past one hundred years. 展开更多
关键词 SEDIMENT Grain size SILT Environment evolution distribution characteristic Hydrogeological engineering Laizhou Bay Qingdao City China
下载PDF
Probability Distribution of Average Length of Node Path and Its Evolution Trace of Aviation Network of China Based on Complex Network
10
作者 Cheng Xiangjun Yang Fang Li Tao 《Journal of Traffic and Transportation Engineering》 2021年第2期41-52,共12页
In order to reveal the complex network feature and its evolution principle of aviation network of China,probability distribution and its evolution trace of average length of node path of aviation network of China were... In order to reveal the complex network feature and its evolution principle of aviation network of China,probability distribution and its evolution trace of average length of node path of aviation network of China were researched according to statistics data in years 1988,1994,2001,2008 and 2015 of civil aviation of China.Floyd algorithm to calculate the path length between any two nodes of network was applied and average length of node path of aviation network was obtained according to this algorithm.It was discovered that average length of node path to other nodes had normal distribution function in each year.At meantime,the location parameter and scale parameter of normal distribution function had linear evolution trace.Airline rate was an index to describe the density of airline.It was found that average length of node path of aviation network of China evolved synchronously with airline rate and they had linear relationship. 展开更多
关键词 Aviation network of China average length of node path probability distribution evolution trace airline rate
下载PDF
Grain Boundary Distribution Evolution of 00Cr12Ti FSS during Annealing 被引量:2
11
作者 YIN Anmin WANG Yufan +2 位作者 SHU Xuedao ZHU Zhenge PENG Hao 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2019年第4期932-939,共8页
The texture and grain boundary of 00Cr12 Ti FSS have a close correlation with properties and should be controlled to optimize the performance of steel sheets. In this paper, the macrotexture evolution during recrystal... The texture and grain boundary of 00Cr12 Ti FSS have a close correlation with properties and should be controlled to optimize the performance of steel sheets. In this paper, the macrotexture evolution during recrystallization annealing was investigated by XRD, the microtexture and grain boundary distribution evolution during recrystallization annealing were investigated by EBSD. The results showed that the γ fiber texture were mainly generated by replacing α fiber texture in recrystallization process. But with the holding time extending,γ fiber texture transferred to other texture after the holding time got to a certain degree. The major CSLs in 00Cr12 Ti FSS after recrystallization are Σ3 and the frequency of Σ3 climb up and then decline with the holding time extending.Σ11 plays an important role in the process of recrystallized γ fiber texture formation. 展开更多
关键词 ferritic STAINLESS texture evolution grain boundary distribution recrystallization
下载PDF
Optimization of the Water Distribution Networks with Differential Evolution (DE) and Mixed Integer Linear Programming (MILP) 被引量:2
12
作者 Ramin Mansouri Hasan Torabi +1 位作者 Mohammd Hoseini Hosein Morshedzadeh 《Journal of Water Resource and Protection》 2015年第9期715-729,共15页
Nowadays, due to increasing population and water shortage and competition for its consumption, especially in the agriculture, which is the largest consumer of water, proper and suitable utilization and optimal use of ... Nowadays, due to increasing population and water shortage and competition for its consumption, especially in the agriculture, which is the largest consumer of water, proper and suitable utilization and optimal use of water resources is essential. One of the important parameters in agriculture field is water distribution network. In this research, differential evolution algorithm (DE) was used to optimize Ismail Abad water supply network. This network is pressurized network and includes 19 pipes and 18 nodes. Optimization of the network has been evaluated by developing an optimization model based on DE algorithm in MATLAB and the dynamic connection with EPANET software for network hydraulic calculation. The developing model was run for the scale factor (F), the crossover constant (Cr), initial population (N) and the number of generations (G) and was identified best adeptness for DE algorithm is 0.6, 0.5, 100 and 200 for F and Cr, N and G, respectively. The optimal solution was compared with the classical empirical method and results showed that implementation cost of the network by DE algorithm was 10.66% lower than the classical empirical method. 展开更多
关键词 DIFFERENTIAL evolution Algorithm OPTIMIZATION distribution Systems CROSSOVER CONSTANT Scale FACTOR
下载PDF
Impact of Sheath Boundary Conditions and Magnetic Flutter on Evolution and Distribution of Transient Particle and Heat Fluxes in the Edge-Localized Mode Burst by Experimental Advanced Superconducting Tokamak Simulation
13
作者 Yan-Bin Wu Tian-Yang Xia +2 位作者 Fang-Chuan Zhong Bin Gui EAST Team 《Chinese Physics Letters》 SCIE CAS CSCD 2019年第4期51-55,共5页
To study the evolution and distribution of the transient particle and heat fluxes during the edge-localized modes(ELMs) burst on the experimental advanced superconducting tokamak(EAST), the BOUT++six-field two-fluid m... To study the evolution and distribution of the transient particle and heat fluxes during the edge-localized modes(ELMs) burst on the experimental advanced superconducting tokamak(EAST), the BOUT++six-field two-fluid model with sheath boundary conditions(SBCs) and magnetic flutter terms in the parallel thermal conduction is used to simulate the evolution of the profiles and growing process of the fluxes at divertor targets. Although SBCs hardly play a role in the linear phase, in the nonlinear phase both SBCs and magnetic flutter can change the dominant toroidal mode. SBCs are able to broaden the frequency distribution of the turbulence. The magnetic flutter increases the ELM size from 2.8% to 8.4%, and it doubles the amplitudes of the radial heat and particle transport coefficients at outer midplane(OMP), at around 1.0 m^2 s^(-1). It is then able to increase the particle and heat flux at the divertor targets and to broaden the radial distribution of the parallel heat flux towards the targets. 展开更多
关键词 evolution distribution conditions
下载PDF
Population Distribution Evolution Characteristics and Shift Growth Analysis in Shiyang River Basin
14
作者 Minzhi Chen Peizhen Wang Li Chen 《International Journal of Geosciences》 2014年第11期1395-1403,共9页
In recent years, the population size and scale of the Shiyang River Basin unceasingly expanding lead to a series of ecological environment: surface water reducing, land desertification and Ground water levels fall, et... In recent years, the population size and scale of the Shiyang River Basin unceasingly expanding lead to a series of ecological environment: surface water reducing, land desertification and Ground water levels fall, etc. Research evolution characteristics of population distribution and migration growth of Shiyang River Basin contribute to river water resources and the industrial development of the comprehensive management. The article using the distribution of population structure index, population distribution center of gravity model and the population migration growth analysis model analyzes the distribution of the population evolution characteristics and population migration growth characteristics of Shiyang River Basin in 2000 to 2010. The results show that: 1) Considering Shiyang River Basin, population density is generally low, population distribution difference is bigger and concentration distribution in the middle corridor plain and three big population distribution center of Minqin oasis area, presenting a “point-areas-ribbon” structure characteristics. 2) The population distribution trend of Shiyang River Basin is constantly concentration, but the change is slow;the population distribution of Minqin is in the highest concentration degree, but the trend has been declining. 3) The focus of population density in river basin locates in Liangzhou district of Daliu country;in ten years, it migrates about 1209 m to southwest Wuwei City direction, but migration along the direction things is bigger than the north and south direction. The focus of population density and the basin geometry center is far away. 4) For ten years, at the township for basic statistics unit, each level population migration change within the overall is not significant: township level > prefecture-level cities level > counties level. 5) For ten years, there are significant changes in population migration between watershed township units, Wuwei City and Gulang Town are the two main concentrations of population centers. 展开更多
关键词 Shiyang RIVER BASIN POPULATION distribution evolution Characteristics SHIFT GROWTH Analysis
下载PDF
Transforming Digital Experiences: The Evolution of Digital Experience Platforms (DXPs) from Monoliths to Microservices: A Practical Guide
15
作者 Sourabh Sethi Sarah Panda 《Journal of Computer and Communications》 2024年第2期142-155,共14页
The research aims to explore the transition from monolithic Digital Experience Platforms (DXPs) to Microservices-based DXPs, addressing scalability challenges. The study systematically decomposes monolithic structures... The research aims to explore the transition from monolithic Digital Experience Platforms (DXPs) to Microservices-based DXPs, addressing scalability challenges. The study systematically decomposes monolithic structures into Microservices, emphasizing business capability and subdomain decomposition. Concrete insights, challenges, and solutions encountered during this transformation process are presented. The research contributes valuable insights into the challenges and benefits of adopting Microservices in DXPs. Results highlight the importance of architectural patterns and strategic scaling dimensions for improved performance and scalability. The case study on Backbase’s Engagement Banking Platform showcases successful implementation, providing flexibility, integration, and efficient development in the evolving DXP landscape. 展开更多
关键词 Digital Experience Platforms (DXPs) Microservices Software evolution Distributed Systems Architectural Patterns
下载PDF
The Limit Distribution of Stochastic Evolution Equations Driven by-Stable Non-Gaussian Noise
16
作者 ZHAI Likai FU Hongbo 《应用数学》 2024年第4期1180-1194,共15页
We study the distribution limit of a class of stochastic evolution equation driven by an additive-stable Non-Gaussian process in the case of α∈(1,2).We prove that,under suitable conditions,the law of the solution co... We study the distribution limit of a class of stochastic evolution equation driven by an additive-stable Non-Gaussian process in the case of α∈(1,2).We prove that,under suitable conditions,the law of the solution converges weakly to the law of a stochastic evolution equation with an additive Gaussian process. 展开更多
关键词 Stochastic evolution equation α-stable Non-Gaussian process distribution
下载PDF
Diploid species phylogeny and evolutionary reticulation indicate early radiation of Ephedra in the Tethys coast
17
作者 Qiong Yu Fu-Sheng Yang +3 位作者 Ya-Xing Chen Hui Wu Stefanie M.Ickert-Bond Xiao-Quan Wang 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2023年第12期2619-2630,共12页
Reconstructing a robust species phylogeny and disentangling the evolutionary and biogeographic history of the gymnosperm genus Ephedra,which has a large genome and rich polyploids,remain a big challenge.Here we recons... Reconstructing a robust species phylogeny and disentangling the evolutionary and biogeographic history of the gymnosperm genus Ephedra,which has a large genome and rich polyploids,remain a big challenge.Here we reconstructed a transcriptome-based phylogeny of 19 diploid Ephedra species,and explored evolutionary reticulations in this genus represented by 50 diploid and polyploid species,using four low-copy nuclear and nine plastid genes.The diploid species phylogeny indicates that the Mediterranean species diverged first,and the remaining species split into three clades,including the American species(Clade A),E.rhytidosperma,and all other Asian species(Clade B).The single-gene trees placed E.rhytidosperma sister to Clade A,Clade B,or Clades A+B in similar proportions,suggesting that radiation and gene flow likely occurred in the early evolution of Ephedra.In addition,reticulate evolution occurred not only among the deep nodes,but also in the recently evolved South American species,which further caused difficulty in phylogenetic reconstruction.Moreover,we found that allopolyploid speciation was pervasive in Ephedra.Our study also suggests that Ephedra very likely originated in the Tethys coast during the late Cretaceous,and the South American Ephedra species have a single origin by dispersal from Mexico or North America. 展开更多
关键词 ALLOPOLYPLOIDY biogeography ephedra PHYLOGENOMICS phylogeny reticulate evolution
原文传递
Molecular evolution,virology and spatial distribution of HCV genotypes in Pakistan:A meta-analysis
18
作者 Arslan Habib Nadiya Habib +10 位作者 Khalid Mahmood Anjum Riffat Iqbal Zeeshan Ashraf Muhammad Usman Taj Muhammad Asim Kanwal Javid Faezeh Idoon Saeid Dashti Cassio Rocha Medeiros Ana Pavla Almeida Diniz Gurgel Henrique Douglas Melo Coutinho 《Infectious Medicine》 2023年第4期324-333,共10页
Background:Hepatitis C,caused by the Hepatitis C Virus(HCV),is the second most common form of viral hepatitis.The geographical distribution of HCV genotypes can be quite complex,making it challenging to ascertain the ... Background:Hepatitis C,caused by the Hepatitis C Virus(HCV),is the second most common form of viral hepatitis.The geographical distribution of HCV genotypes can be quite complex,making it challenging to ascertain the most prevalent genotype in a specific area.Methods:To address this,a review was conducted to determine the prevalence of HCV genotypes across various provinces and as a whole in Pakistan.The scientific literature regarding the prevalence,distribution,genotyping,and epidemiology of HCV was gathered from published articles spanning the years 1996-2020.Results:Genotype 1 accounted for 5.1%of the patients,with its predominant subtype being 1a at 4.38%.The frequencies of its other subtypes,1b and 1c,were observed to be 1.0%and 0.31%respectively.Genotype 2 had a frequency of 2.66%,with the most widely distributed subtype being 2a at 2.11%of the patients.Its other subtypes,2b and 2c,had frequencies of 0.17%and 0.36%respectively.The most prevalent genotype among all isolates was 3(65.35%),with the most frequent subtype being 3a(55.15%),followed by 3b(7.18%).The prevalence of genotypes 4,5,and 6 were scarce in Pakistan,with frequencies of 0.97%,0.08%,and 0.32%respectively.The prevalence of untypeable and mixed genotypes was 21.34%and 3.53%respectively.Estimating genotypes proves to be a productive method in assisting with the duration and selection of antiviral treatment.Different HCV genotypes can exhibit variations in their response to specific antiviral treatments.Different genotypes may have distinct natural histories,including variations in disease progression and severity.Some genotypes may lead to more rapid liver damage,while others progress more slowly.Conclusions:This information can guide screening and testing strategies,helping to identify individuals at higher risk of developing severe complications.Studying the distribution of HCV genotypes in a population can provide valuable insights into the transmission dynamics of the virus. 展开更多
关键词 GENOTYPES HCV Molecular evolution Pakistan Spatial distribution
原文传递
Evolution and Frontogenesis of an Imbalanced Flow- the Influence of Vapor Distribution and Orographic Forcing 被引量:6
19
作者 王云峰 伍荣生 潘益农 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2000年第2期256-274,共19页
If the initial fields are not in geostrophic balance, the adjustment and evolution will occur in the stratified fluid. and the frontogenesis will occur under suitable conditions. The evolution is studied here with a n... If the initial fields are not in geostrophic balance, the adjustment and evolution will occur in the stratified fluid. and the frontogenesis will occur under suitable conditions. The evolution is studied here with a nonhydrostatic fully compressible meso-scale model (Advanced Regional Prediction System, ARPS). Four cases are designed and compared: (i) control experiment: (ii) with different initial temperature gradient; (iii) with vapor distribution; (iv) with orographic forcing. The results show that: (1) there is an inertial oscillation in the evolution of the imbalanced flow with the frequency of the local Coriolis f, and with its amplitude decreasing with time. The stationary balanced state can only be approached as it cannot be reached in the limit duration of time. The energy conversion ratio varies in the range of [0, 1; 3]; (2) the stronger initial temperature gradient can make the final energy conversion ratio higher. and vice versa; (3) suitable vapor distribution is favorable for the frontogenesis. It will bring forward the time of the frontogenesis, strengthen the intensity of the cold front, and influence the final energy conversion ratio; (4) the orographic forcing has an evidently strengthening effect on the frontogenesis. The strengthening effect on the frontogenesis and the influence on the final energy conversion ratio depend on the relative location of the mountain to the cold front. 展开更多
关键词 evolution FRONTOGENESIS inertial oscillation vapor distribution and orographic forcing
下载PDF
Distribution Network Reactive Power Optimization Based on Ant Colony Optimization and Differential Evolution Algorithm 被引量:1
20
作者 Y.L. Zhao Q. Yu C.G. Zhao 《Journal of Energy and Power Engineering》 2011年第6期548-553,共6页
Due to the inherent complexity, traditional ant colony optimization (ACO) algorithm is inadequate and insufficient to the reactive power optimization for distribution network. Therefore, firstly the ACO algorithm is... Due to the inherent complexity, traditional ant colony optimization (ACO) algorithm is inadequate and insufficient to the reactive power optimization for distribution network. Therefore, firstly the ACO algorithm is improved in two aspects: pheromone mutation and re-initialization strategy. Then the thought of differential evolution (DE) algorithm is proposed to be merged into ACO, and by producing new individuals with random deviation disturbance of DE, pheromone quantity left by ants is disturbed appropriately, to search the optimal path, by which the ability of search having been improved. The proposed algorithm is tested on IEEE30-hus system and actual distribution network, and the reactive power optimization results are calculated to verify the feasibility and effectiveness of the improved algorithm. 展开更多
关键词 Ant colony optimization distribution network differential evolution reactive power optimization.
下载PDF
上一页 1 2 87 下一页 到第
使用帮助 返回顶部