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State-Resolved Ar II Population Distributions under Femtosecond Strong-Field Excitation 认领 引用
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作者 Di Wang Yuxuan Zhang +7 位作者 Zhigang Zheng Mingyue Wang Zhihui Lv Li Wang Xiaowei Wang Dongwen Zhang Jing Zhao Zengxiu Zhao 《Chinese Physics Letters》 SCIE EI CAS CSCD 2026年第6期22-26,共5页
We measure spontaneous emission from Ar II ions produced by femtosecond strong-field excitation of argon and reconstruct state-resolved excited-state populations from selected emission lines spanning upper-level energ... We measure spontaneous emission from Ar II ions produced by femtosecond strong-field excitation of argon and reconstruct state-resolved excited-state populations from selected emission lines spanning upper-level energies of~19-23 eV above the Ar II ground state.The ionic-line intensities follow a power-law dependence on pulse energy and a non-monotonic dependence on gas pressure,and the extracted populations deviate significantly from a Boltzmann distribution.The deviation grows with increasing pulse energy,reflecting a stronger nonequilibrium character of the initial population prepared by the strong field,and weakens with increasing gas pressure,consistent with collisional redistribution driving the system toward thermal equilibrium.These results establish ionic fluorescence as a practical state-resolved probe of nonequilibrium population distributions in strong-field-ionized argon. 展开更多
关键词 femtosecond strong field excitation AR II ions emission lines boltzmann distributionthe spontaneous emission ionic line intensities population distributions state resolved
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Population distribution and urbanization on both sides of the Hu Huanyong Line:Answering the Premier's question 认领 引用 被引量：24
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作者 陈明星 龚颖华 +2 位作者 李扬 陆大道 张华 《Journal of Geographical Sciences》 SCIE CSCD 2016年第11期1593-1610,共18页
In late November 2014, while attending a science exhibition on human settlement at the National Museum, Premier Li Keqiang posed a question to society and scientists regard- ing the Hu Huanyong Line, which the media s... In late November 2014, while attending a science exhibition on human settlement at the National Museum, Premier Li Keqiang posed a question to society and scientists regard- ing the Hu Huanyong Line, which the media subsequently dubbed ＂the Premier＇s question＂. This increased awareness and interest in the Hu Huanyong Line and launched a lively debate which provoked a variety of views. In an attempt to address the Premier＇s question, this paper firstly reviews the origins of the Hu Huanyong Line, named after the famous population ge- ographer who proposed it in 1935 as part of a wider debate on domestic overpopulation. Using demographic data from ChJna＇s first, fifth and sixth censuses, as well as the ArcGIS platform, we analyze the size, proportion and density of populations in the areas southeast and northwest of the Hu Huanyong Line, showing that urbanization and migration have not changed the pattern of population distribution observed by Hu Huanyong. Based on this, we suggest that the pattern of a dense population southeast of the line and sparse population northwest of the line will not fundamentally change for a relatively long time, nor will the situation of urban agglomerations being mainly found in the southeastern region. We also argue that climate and other physical geographic conditions determine that the Hu Huanyong Line shall remain in place. We believe that the question posed by Premier Li Keqiang is solvable, and that with positive policy guidance and rational spatial organization, the north- western region can achieve more modernization and better quality urbanization, while the same is true for the central region. 展开更多
关键词 Hu Huanyong Line Premier＇s question population distribution urbanization patterns trends
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Relief degree of land surface and its influence on population distribution in China 认领 引用 被引量：49
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作者 FENG Zhiming TANG Yan +1 位作者 YANG Yanzhao ZHANG Dan 《Journal of Geographical Sciences》 SCIE 2008年第2期237-246,共10页
The relief degree of land surface （RDLS） is an important factor for describing the landform at macro-scales. This study defines a concept for RDLS and applies the concept for population distribution study of the ent... The relief degree of land surface （RDLS） is an important factor for describing the landform at macro-scales. This study defines a concept for RDLS and applies the concept for population distribution study of the entire country. Based on the concept and macro-scale digital elevation model datum and ARC/INFO software, the RDLS at a 10 km×10 km grid size of China is extracted. This paper depicts systemically the spatial distributions of RDLS through analyzing the ratio structure and altitudinal characters of RDLS in China. The conclusions are drawn as follows： the RDLS in more than 63% of the area is less than one （1） （relative altitude is less than 500 m）, reflecting the fact that most of RDLS in China is low. In general, the RDLS in the west is larger than that in the east and so is the south than that of the north in China. The RDLS decreases with the increase of longitude and latitude and the change of RDLS at the latitudes of 28°N, 35°N, 42°N, as well as at the longitudes of 85°E, 102°E, 115°E could reflect the three major ladders of China. In the vertical direction, the RDLS increases with the increase of altitude. Analysis of the correlation between RDLS and population distribution in China and its regional difference shows that the R2 value between RDLS and population density is 0.91 and RDLS is an important factor influencing the spatial distribution of population. More than 85% of the people in China live in areas where the RDLS is less than one （1）, while the population in areas with RDLS greater than 3 accounts only for 0.57% of the total. The regional difference of correlation between RDLS and population within China is significant and such correlation is significant in Central China and South China and weak in Inner Mongolia and Tibet. 展开更多
关键词 relief degree of land surface （RDLS） population distribution GIS China
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Relief Degree of Land Surface and Population Distribution of Mountainous Areas in China 认领 引用 被引量：14
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作者 LIU Ying DENG Wei SONG Xue-qian 《Journal of Mountain Science》 SCIE CSCD 2015年第2期518-532,共15页
Evaluation on the population pressure in the mountainous areas is a necessary condition for the protection and good governance. The evaluation depends on accurate population density assessment. Traditional methods use... Evaluation on the population pressure in the mountainous areas is a necessary condition for the protection and good governance. The evaluation depends on accurate population density assessment. Traditional methods used to calculate population density often adopt the administrative region as a scale for statistical analysis. These methods did not consider the effects of the relief degree of land surface(RDLS) on the population distribution. Therefore they cannot accurately reflect the degree of population aggregation, especially in mountainous areas. To explore this issue further, we took the mountainous areas of China as the research area. China has A total area of 666 km2 can be classified as mountainous area,accounting for 69.4% of the country's total landmass. The data used in this research included the digital elevation model(DEM) of China at a scale of 1:1,000,000, National population density raster data, the DEM and the national population density raster data. First, we determined the relief degree of land surface(RDLS). Next, we conducted a correlation analysis between the population distribution and the RDLS using the Statistical Package for Social Science(SPSS). Based on the correlation analysis results and population distribution, this new method was used to revise the provincial population density of themountainous areas. The revised results were used to determine the population pressure of different mountainous areas. Overall, the following results were obtained:(1) The RDLS was low in most mountainous areas(with a value between 0 and 3.5) and exhibited a spatial pattern that followed the physiognomy of China;(2) The relationship between the RDLS and population density were logarithmic, with an R2 value up to 0.798(p<0.05), and the correlation decreased from east to west;(3) The difference between the revised population density(RPD) and the traditional population density(PD) was larger in the southeastern region of China than in the northwestern region;(4) In addition, compared with traditional results, the revised result indicated that the population pressure was larger. Based on these results, the following conclusions were made:(1) the revised method for estimating population density that incorporates the RDLS is reasonable and practical,(2) the potential population pressure in the southeastern mountainous areas is substantial,(3) the characteristics of the terrain in the high mountainous areas are important for the scattered distribution of the population, and(4) the population distribution of mountainous areas in China should be guided by local conditions, such as social, economic, and topographic conditions. 展开更多
关键词 Land surface Relief degree Population density Population pressure Population distribution Mountain China
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Character and Causes of Population Distribution in Shenyang City,China 认领 引用 被引量：12
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作者 DU Guoming ZHANG Shuwen ZHANG Youquan 《Chinese Geographical Science》 SCIE 2006年第3期217-222,共6页
Character of population distribution is one of the focuses studied by urban geography. Using the fifth national census data as basic data and using areal interpolation method, this paper analyzes character of urban po... Character of population distribution is one of the focuses studied by urban geography. Using the fifth national census data as basic data and using areal interpolation method, this paper analyzes character of urban population dis- tribution of Shenyang City, Northeast China, in terms of three aspects of statistical character, spatial auto-correlation and spatial structure. Furthermore, this research analyzes the factors affecting the population distribution of the city. The main conclusions include: 1) There is an obvious structure character of population distribution in the grid with a grain of 300m, which is appropriate scale when researching population distribution in Shenyang City. 2) Urban population dis- tribution has the character of assembling while population density distribution takes on variability in Shenyang City. 3) Population density distribution shows spatial auto-correlation within 7.36km. Spatial heterogeneity of population density is low. 4) Urban center, population distribution barycenter and population density maximum points separate each other. Population density distribution has multi-cores character. 5) Layout of governments, primary schools, middle schools, colleges, hospitals and marketplaces affects population distribution directly. With the increase of distance to these factors, population density decreases as logarithm. 展开更多
关键词 population density model population distribution scale Shenyang City
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Dual-environment feature fusion-based method for estimating building-scale population distributions 认领 引用 被引量：1
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作者 Guangyu Liu Rui Li +4 位作者 Jing Xia Zhaohui Liu Jing Cai Huayi Wu Mingjun Peng 《Geo-Spatial Information Science》 SCIE EI CSCD 2024年第6期1943-1958,共16页
Information on the population distribution at the building scale can help governments make supplemental decisions to address complex urban management issues.However,the discontinuity and strong spatial heterogeneity o... Information on the population distribution at the building scale can help governments make supplemental decisions to address complex urban management issues.However,the discontinuity and strong spatial heterogeneity of research units at the building scale make it challenging to fuse multi-source geographic data,which causes significant errors in population estimation.To address this problem,this study proposes a method for population estimation at the building scale based on Dual-Environment Feature Fusion(DEFF).The dual environments of buildings were constructed by splitting the physical boundaries and extracting features suitable for the dual-environment scale from multi-source geographic data to describe the complex environmental features of buildings.Meanwhile,Data Quality Weighting based Technique for Order of Preference by Similarity to Ideal Solution(DQW-TOPSIS)method was proposed to assign appropriate weights to the features of the external environment for better feature fusion.Finally,a regression model was established using dual-environment features for building-scale population estimation.The experimental areas chosen for this study were Jianghan and Wuchang Districts,both located in Wuhan City,China.The estimated results of the DEFF were compared with those of the ablation experiments,as well as three publicly accessible population datasets,specifically LandScan,WorldPop,and GHS-POP,at the community scale.The evaluation results showed that DEFF had an R2 of approximately 0.8,Mean Absolute Error(MAE)of approximately 1200,Root Mean Square Error(RMSE)of approximately 1700,and both Mean Absolute Percentage Error(MAPE)and Symmetric Mean Absolute Percentage Error(SMAPE)of approximately 26%,indicating an improved performance and verifying the validity of the proposed method for fine-scale population estimation. 展开更多
关键词 Building scale multi-source data fusion estimation of population distribution dual environment Data Quality Weighting based Technique for Order of Preference by Similarity to Ideal Solution(DQW-TOPSIS)
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Population distribution, structure and growth condition of Antarctic krill(Euphausia superba Dana) during the austral summer in the Southern Ocean 认领 引用 被引量：3
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作者 SHI Yongqiang SUN Song +1 位作者 LI Chaolun TAO Zhencheng 《Advances in Polar Science》 2014年第3期183-191,共9页
Antarctic krill （Euphausia superba Dana） was collected using a High Speed Collector and an Isaac-Kidd midwater trawl （IKMT） net during the austral summer of 2007/2008 and 2008/2009 in the circumpolar and Prydz Bay... Antarctic krill （Euphausia superba Dana） was collected using a High Speed Collector and an Isaac-Kidd midwater trawl （IKMT） net during the austral summer of 2007/2008 and 2008/2009 in the circumpolar and Prydz Bay regions of the Southern Ocean, respectively. Combined with the simultaneous recording of environmental factors, spatial distribution, population structure and growth condition of E. superba were studied. The abundance of E. superba in the Weddell Sea was higher than in Prydz Bay. However, the abundance of E. superba in both the Weddell Sea and Prydz Bay was lower than figures reported in previous krill surveys for the same time period. With respect to the total study area, E. superba displayed a normal growing state during the two expeditions. E. superba grew relatively poorly in some stations, which may be due to the late retreat of sea ice or lower chlorophyll a concentrations. The number of juvenile E. superba collected using the High Speed Collector was proportionally greater in stations located at the edge of the sea ice, while adults dominated in long-term non-ice regions. This phenomenon reflects the different distribution pattern between juvenile and adult krill. The population structure of E. superba differed between sea regions, which may affect recruitment. 展开更多
关键词 Euphausia superba population distribution growing state sea ice WeddeH Sea Prydz Bay
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Population Distribution of Excited States in Cs Electrodeless Discharge Lamp 认领 引用
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作者 祝传文 陶智明 +4 位作者 陈默 刘忠征 张晓刚 张盛楠 陈景标 《Chinese Physics Letters》 SCIE EI CAS CSCD 2015年第6期40-42,共3页
We measure the intensity of fluorescence spectral lines of Cs atoms in an electrodeless discharge lamp from visible light to the near-infrared region of 400-100Ohm. To build an excited state Faraday anomalous dispersi... We measure the intensity of fluorescence spectral lines of Cs atoms in an electrodeless discharge lamp from visible light to the near-infrared region of 400-100Ohm. To build an excited state Faraday anomalous dispersion optical filter, the population ratios between the excited states are calculated by rate equations and the spontaneous transition probabilities. The electrodeless discharge lamp with populations in the excited states can be used to realize the frequency stabilization reference for lasers at multiwavelength and the excited state Faraday anomalous dispersion optical filter for submarine communication applications in blue-green wavelengths to simplify the system. 展开更多
关键词 Population Distribution of Excited States in Cs Electrodeless Discharge Lamp Cs
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Population Distribution and Influencing Factors Based on ESDA 认领 引用 被引量：4
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作者 Lv Chen Fan Jie Sun Wei 《Chinese Journal of Population,Resources and Environment》 2012年第3期47-53,共7页
Based on the exploratory spatial data analysis （ESDA） technique and geographic information system （GIS） platform, with statistic data of counties in 2005, this paper confirms that there is a large population densi... Based on the exploratory spatial data analysis （ESDA） technique and geographic information system （GIS） platform, with statistic data of counties in 2005, this paper confirms that there is a large population density gap between counties in 2005 because the Gini coefficient is 0.55. Population distribution does not change a lot during the past decades, and the southeast China is still much more densely populated than the northwest China. The global spa- tial autoeorrelation of population distribution is obvious because Moran＇s I scores 0.42 and local spatial autocorrelation is partly significant. Climate and elevation are still the main natural influ- encing factors. Meanwhile industrial structure and transportation significantly influence population distribution. Different combinations of natural factors have different effects on population distribution. For a long term, climate and terrain factor stability affect population distribution. But its influence will be weakened by progress of technology. Economic development is the main factor that changes population distribution for a short term. 展开更多
关键词 population distribution geographic information system （GIS） spatial autocorrelation influencing factors
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Heterogeneous population distribution enhances resistance to wheat lodging by optimizing the light environment 认领 引用
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作者 Yibo Hu Feng Qin +6 位作者 Zhen Wu Xiaoqin Wang Xiaolong Ren Zhikuan Jia Zhenlin Wang Xiaoguang Chen Tie Cai 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第7期2211-2226,共16页
Lodging is still the key factor that limits continuous increases in wheat yields today,because the mechanical strength of culms is reduced due to low-light stress in populations under high-yield cultivation.The mechan... Lodging is still the key factor that limits continuous increases in wheat yields today,because the mechanical strength of culms is reduced due to low-light stress in populations under high-yield cultivation.The mechanical properties of the culm are mainly determined by lignin,which is affected by the light environment.However,little is known about whether the light environment can be sufficiently improved by changing the population distribution to inhibit culm lodging.Therefore,in this study,we used the wheat cultivar“Xinong 979”to establish a low-density homogeneous distribution treatment(LD),high-density homogeneous distribution treatment(HD),and high-density heterogeneous distribution treatment(HD-h)to study the regulatory effects and mechanism responsible for differences in the lodging resistance of wheat culms under different population distributions.Compared with LD,HD significantly reduced the light transmittance in the middle and basal layers of the canopy,the net photosynthetic rate in the middle and lower leaves of plants,the accumulation of lignin in the culm,and the breaking resistance of the culm,and thus the lodging index values increased significantly,with lodging rates of 67.5%in 2020–2021 and 59.3%in 2021–2022.Under HD-h,the light transmittance and other indicators in the middle and basal canopy layers were significantly higher than those under HD,and the lodging index decreased to the point that no lodging occurred.Compared with LD,the activities of phenylalanine ammonia-Lyase(PAL),4-coumarate:coenzyme A ligase(4CL),catechol-O-methyltransferase(COMT),and cinnamyl-alcohol dehydrogenase(CAD)in the lignin synthesis pathway were significantly reduced in the culms under HD during the critical period for culm formation,and the relative expression levels of TaPAL,Ta4CL,TaCOMT,and TaCAD were significantly downregulated.However,the activities of lignin synthesis-related enzymes and their gene expression levels were significantly increased under HD-h compared with HD.A partial least squares path modeling analysis found significant positive effects between the canopy light environment,the photosynthetic capacity of the middle and lower leaves of plants,lignin synthesis and accumulation,and lodging resistance in the culms.Thus,under conventional high-density planting,the risk of wheat lodging was significantly higher.Accordingly,the canopy light environment can be optimized by changing the heterogeneity of the population distribution to improve the photosynthetic capacity of the middle and lower leaves of plants,promote lignin accumulation in the culm,and enhance lodging resistance in wheat.These findings provide a basis for understanding the mechanism responsible for the lower mechanical strength of the culm under high-yield wheat cultivation,and a theoretical basis and for developing technical measures to enhance lodging resistance. 展开更多
关键词 canopy light environment lignin lodging population distribution wheat
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Relationship between Physico-Chemical Parameters and the Population Distribution of Fresh Water Snails in Amassoma Community and Niger Delta University Campuses,Bayelsa State,Nigeria 认领 引用
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作者 Amawulu Ebenezer Akpoebiere O.Mercy Ekwuribe 《Research in Ecology》 CAS 2022年第1期1-6,共6页
Evaluating the presence of fresh water snails in a location is germane in establishing a snail-borne disease control program.The purpose of the study was to see how physicochemical parameters influenced the population... Evaluating the presence of fresh water snails in a location is germane in establishing a snail-borne disease control program.The purpose of the study was to see how physicochemical parameters influenced the population distribution of four fresh water snails(Lymnaea natalensis,Bulinus globosus,Biomphalaria pfeiffer,and Melanoides spp.)in the Amassoma community and Niger Delta University between March,2021 and May 2021.Snails were gathered by plucking and scooping them by hand.Snail was identified using standard pictorial keys.Physicochemical of the water of the snail habitat were measured using standard in-situ apparatus across eight sites Physico chemical measured were temperature,pH,conductivity,BOD,turbidity,salinity,and alkalinity.A total of 258 snails were gathered from the eight(8)different sites.In all sites,Lymnaea natalensis was more abundant.Bulinus globosus,Biomphalaria pfeiffer,and Melanoides spp.were among the other snails discovered.Lymnaea had negative correlation with pH,conductivity,BOD,and alkalinity and a positive correlation with salinity and temperature.Bulinus had a positive relationship with pH,salinity,and conductivity and a negative correlation with temperature,turbidity,BOD,and alkalinity.Biomphalaria had a positive correlation with temperature,pH,salinity,turbidity,and alkalinity Melanoides had positive correlations with Temperature,pH,salinity,BOD,and alkalinity and a negative correlation with turbidity and concentration.The was correlation between snails and snails.The presence of these snails suggests that the Amassoma village and Niger Delta University campuses are potential hotspots for a variety of snail-borne diseases. 展开更多
关键词 Physico-chemical parameters Population distribution Fresh-water snail Amassoma community Niger Delta University
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Spatial Morphology Evolution Characteristics Analysis of the Resident Population Distribution in Henan, China 认领 引用 被引量：1
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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
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Research on the Variation of Population Distribution and Its Characteristics Based on Spatial Autocorrelation Method: A Case Study of Poyang Lake Region in Jiangxi Province 认领 引用
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作者 Luo Hui Yang Weichun 《Chinese Journal of Population,Resources and Environment》 2010年第4期76-78,共3页
According to Statistical Yearbook of Jiangxi Province(2001～2006),We analyze the time-space variation of population distribution of Poyang Lake region from the two points of view.The former is quality of population,wh... According to Statistical Yearbook of Jiangxi Province(2001～2006),We analyze the time-space variation of population distribution of Poyang Lake region from the two points of view.The former is quality of population,which involves culture structure,occupational structure,age structure and sex structure of population.The latter is quantity of population,which only involves the amount of population.Furthermore,we can reveal the internal relations and action mechanism of variation of population distribution by analyzing the regional economic development,population urbanization,land use and ecological landscape of Poyang Lake region.It is important to provide help for region planning,ecological landscape planning and environmental protection by correct understanding the man-land relationship of natural-human ecosystem in Poyang Lake region. 展开更多
关键词 population distribution spatial autocorrelation changing characteristics Poyang Lake region
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Quantitative Analysis on the Relationship between Population Distribution and Environment Factors in Mountain Area 认领 引用
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作者 SUN Yu-lian ZHAO Yong-tao +2 位作者 CAO Wei-chao YU Hui MA Yue-wei 《Meteorological and Environmental Research》 2011年第3期77-80,共4页
[Objective]The aim was to analyze the relationship between population distribution and environment factors in mountain area quantitatively.[Method]Taking the contiguous area of Sichuan,Yunnan and Guizhou Province as s... [Objective]The aim was to analyze the relationship between population distribution and environment factors in mountain area quantitatively.[Method]Taking the contiguous area of Sichuan,Yunnan and Guizhou Province as study object,population density and residential point density were chosen as the indices of population distribution,and the quantitative relationship between population distribution and environment factors(including altitude,topography relief amplitude,land use,road network and river network)in mountain area was analyzed.[Result]Altitude and topography relief amplitude in mountain area had obvious negative correlation with population density and residential point density,and the correlation coefficients with population density were-0.731 and-0.743.In addition,residential points were fewer in the region far from rivers,but there was no obvious correlation between population density and river network density.Residential point density was higher in cultivated land and construction land,and population density had obvious positive correlation with the area proportions of cultivated land and construction land,with the correlation coefficients of 0.895 and 0.726,respectively.Besides,the more distant from road,the smaller residential point density,and there was obvious positive correlation between population density and road network density,with the correlation coefficient of 0.823.[Conclusion]The study could lay a foundation for the further development of spatiality of population data in study region. 展开更多
关键词 Population distribution Environmental factors Quantitative analysis Mountain area China
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Population distribution, urban construction and urban management in the process of China urbanization 认领 引用 被引量：1
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作者 ZHANG Shu-jie 《Chinese Business Review》 2009年第9期54-57,共4页
Along with China＇s urbanization, a series of problems came, such as the rapidly expanding urban population, large-scale urban construction and investment, the financing gap of government＇s investment in construction... Along with China＇s urbanization, a series of problems came, such as the rapidly expanding urban population, large-scale urban construction and investment, the financing gap of government＇s investment in construction, and urban management, etc. This article first describes the growth of urban population, the scale and the input of urban construction, and then analyzes the financial revenue and expenditure, and at last argues for the necessity of urban management, and puts forward the research content of urban management. 展开更多
关键词 urban management urbanization financial revenue population distribution and growth
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Population Distribution and Agglomeration Patterns in Nepal 认领 引用
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作者 YOU Zhen TAN Huaxin +2 位作者 YANG Yanzhao CHEN Yijie DONG Kuanwei 《Journal of Resources and Ecology》 CAS CSCD 2026年第1期257-264,共8页
Population distribution and agglomeration patterns are critical indicators of regional economic and social development.Analyzing Nepal’s population distribution and agglomeration patterns can provide valuable insight... Population distribution and agglomeration patterns are critical indicators of regional economic and social development.Analyzing Nepal’s population distribution and agglomeration patterns can provide valuable insights into the underlying spatial distribution,while offering data support and theoretical foundations for formulating effective regional development strategies.This study uses population and land data from Nepal’s counties for the years 1981,2001,and 2021,and employs quantitative analysis methods,including the Gini coefficient,population growth rate,and population concentration index to systematically examine the spatiotemporal evolution and agglomeration patterns.The results show three key insights.(1)The degree of population distribution imbalance has increased,with the Gini coefficient rising from 0.424 in 1981 to 0.531 in 2021.(2)Population growth follows a regional pattern of“rapid growth in the south and slower growth in the north,”with the Terai Plain experiencing rapid expansion,the central mountainous region growing steadily,and the northern highland areas experiencing slow growth.(3)The population concentration displays a tiered distribution pattern of“high concentration in the plains,significant differentiation in the mountainous areas,and extreme sparsity in the high mountain regions”. 展开更多
关键词 population distribution agglomeration patterns population concentration index Nepal
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Runtime Analysis in Non-Elitist Evolutionary Algorithms via Population Distribution 认领 引用
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作者 NI Xuanming ZHAO Qiaochu +1 位作者 HUANG Song YU Lian 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2025年第3期1092-1108,共17页
In recent decades,significant advancements have been made in the rigorous runtime analysis of evolutionary algorithms(EAs).However,in the context of non-elitist EAs and the use of crossover,it is challenging to engage... In recent decades,significant advancements have been made in the rigorous runtime analysis of evolutionary algorithms(EAs).However,in the context of non-elitist EAs and the use of crossover,it is challenging to engage in any meaningful theoretical discussion due to the increasing complexity of the EA's population distribution as the EA runs.This paper aims to gain insight into the rigorous runtime analysis of the(μ,λ)EA with crossover,focusing on its optimization of the Jump test function,by investigating the population distribution during the optimization process.It is proposed that,under typical circumstances,the population distribution will first reach a stable and fully-diverged state before attaining the global optimum.Consequently,the optimization process is divided into two parts,based on whether the population distribution has reached this state.By investigating this state,the authors are able to provide a better upper bound on the runtime of the EA.Furthermore,a series of experiments were conducted to validate our theoretical results,which also offered insights into the impact of different parameters on this state. 展开更多
关键词 Crossover evolutionary algorithms(EAs) population distribution runtime analysis
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Population distribution modelling at fine spatio-temporal scale based on mobile phone data 认领 引用 被引量：7
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作者 Petr Kubicek Milan Konecny +6 位作者 Zdenek Stachon Jie Shen Lukas Herman Tomas Reznik Karel Stanek Radim Stampach Simon Leitgeb 《International Journal of Digital Earth》 SCIE EI 2019年第11期1319-1340,共22页
Population distribution modelling can benefit many different domains,for example,transportation,urban planning,ecology or emergency management.Information about the location and number of people in an affected area is... Population distribution modelling can benefit many different domains,for example,transportation,urban planning,ecology or emergency management.Information about the location and number of people in an affected area is crucial for decision-makers during emergencies and crises.Mobile phone data represents relatively reliable and time accurate information on real-time population distribution,movement and behaviour.In this study,we evaluate the spatio-temporal distribution of population derived from phone data of the selected pilot area(City of Brno,Czech Republic).Analysis is based on the dataset describing the estimated human presence(EHP)with two values-visitors and transiting persons.The temporal change of data is first analysed and further processed using two methodological approaches.First,the dasymetric method is used where the building geometry and technical attributes served as a target layer.Second,the results of building level analysis are transformed into a regular grid zone of both visitors and the general EHP.Resulting spatio-temporal patterns are compared to the census data.Results demonstrate how the proposed building level dasymetric approach can improve the spatial granularity of EHP.Potential use of proposed methodology within selected emergency situations is further discussed. 展开更多
关键词 Population distribution modelling mobile phone data estimated human presence emergency management
Underground space use of urban built-up areas in the central city of Nanjing:Insight based on a dynamic population distribution 认领 引用 被引量：5
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作者 Yulu Chen Zhilong Chen +3 位作者 Dongjun Guo Ziwei Zhao Tong Lin Chenhao Zhang 《Underground Space》 SCIE CSCD 2022年第5期748-766,共19页
With the expansion of cities and the emergence of various urban problems,urban underground space has been developed as a solution.In China’s urban transition context,there is a need for the development of underground... With the expansion of cities and the emergence of various urban problems,urban underground space has been developed as a solution.In China’s urban transition context,there is a need for the development of underground space in urban built-up areas.In this casestudy of the central city of Nanjing,we used spatial analysis and statistical methods to characterize the underground space use of urban built-up areas from a dynamic spatiotemporal perspective.We first analyzed the relationship between the population distribution and the underground space use of the central city of Nanjing based on a Baidu heat map,which can reflect the real-time population distribution,and then,we explored the spatiotemporal characteristics and spatial structure of the underground space use in urban built-up areas.The analysis results provide a reference for planning to improve and optimize the layout of underground space in the central city of Nanjing and,more generally,for the stock-type planning of underground space in urban built-up areas. 展开更多
关键词 Underground space use Dynamic population distribution Urban built-up area Spatiotemporal characteristics
Atomic population distribution of excited states in He electrodeless discharge lamp 认领 引用 被引量：1
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作者 陶智明 王彦飞 +4 位作者 张盛楠 王东颖 洪叶龙 庄伟 陈景标 《Chinese Optics Letters》 SCIE EI CAS CSCD 2013年第10期11-14,共4页
Population ratios between excited states are measured to build the excited state Faraday anomalous dispersion optical filter(ESFADOF). We calculate these values between the excited states according to the spontaneous ... Population ratios between excited states are measured to build the excited state Faraday anomalous dispersion optical filter(ESFADOF). We calculate these values between the excited states according to the spontaneous transition probabilities using rate equations and the measured intensities of fluorescence spectral lines of He atoms in an electrodeless discharge lamp in the visible spectral region from 350 to 730 nm. The electrodeless discharge lamp with populations in excited states can be used to realize the frequency stabilization reference of the laser frequency standard. This lamp can also build ESFADOFs for submarine communication application in the blue-green wavelength to simplify the system without the use of a pump laser. 展开更多
关键词 rate Atomic population distribution of excited states in He electrodeless discharge lamp
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