Papers by Keyword: Spatial Distribution

Abstract: To meet the growing demand for everyday leisure and improve land use efficiency, high-density mixed-use development and compact, spatially efficient planning strategies are increasingly being adopted in small and medium-sized cities. This study investigates how the spatial distribution of public leisure and cultural facilities affects residents' perceived accessibility in this context. Key indicators include spatial concentration, spatial equity, and diversity, analyzed using a multilevel ordinal logistic regression model—an extension of the Hierarchical Linear Model (HLM). The findings reveal that higher spatial concentration is significantly associated with greater perceived accessibility. Notably, several cities in Jeollanam-do demonstrate high accessibility perceptions despite a limited number of facilities, due to their strategic placement within core neighborhood zones. Conversely, spatial equity and diversity showed no significant effect. These results suggest that high-density development strategies can be effective even in smaller cities and highlight the importance of neighborhood-level planning that achieves a balance between concentration and equity.

Abstract: Underground mining has caused drastic disturbances to regional ecosystems and soil nutrients. Understanding the 3D spatial distribution of soil organic matter in coal arable land is crucial for agricultural production and environmental management. However, little research has been done on the three-dimensional modeling of soil organic matter. In this study, 3D kriging interpolation method and 3D stochastic simulation method were used to develop the 3D model of soil organic matter , and the root-mean-square error (RMSE) and mean error (ME) were used as evaluation indexes to compare the simulation accuracy of the two methods. Results showed that the spatial distribution of soil organic matter obtained by using 3D kriging interpolation method is relatively smooth, which reduce the difference of spatial data; while the spatial distribution of soil organic matter obtained by using 3D stochastic simulation method is relatively discrete and highlights the volatility of spatial distribution of raw data, the RMSE obtained by 3D kriging interpolation method and 3D stochastic simulation method respectively is 2.7711 g/kg and 1.8369 g/kg. The prediction accuracy of organic matter interpolation obtained by 3D stochastic simulation method is higher than that by 3D kriging interpolation method; so the 3D stochastic simulation method can reflect the spatial distribution characteristics of soil organic matter more realistically, and more suitable for 3D modeling of soil organic matter. According to the 3D modeling of soil organic matter, the content of soil organic matter has obvious spatial difference in different soil depth（0-20 cm、20-40 cm、40-60 cm） and decreases with the increase of soil depth; The result also showed that the content of soil organic matter decreased rapidly from the upper slope to the middle slope, and gradually increased from the middle slope to the bottom, so the soil organic matter content was obviously lost in the middle slope. This result may provide useful data for land reclamation and ecological reconstruction in coal mining subsidence area.

Abstract: Two 6xxx alloys with different Mn-content have been homogenised in a furnace at 575 ^oC for 2 hours and 15 minutes. Three different heating rates to the homogenisation holding temperature were chosen, as this was expected to affect the precipitation behaviour of the dispersoids. The study focused on developing a reliable procedure for the characterization of the density and spatial distribution of dispersoids in aluminium alloys; both in terms of sample preparation, microscopic techniques and quantitative analyses of results. Scanning electron microscopy (SEM) has been used to evaluate the dispersoid characteristics for the different alloys and heating rates. The results indicate an increase in dispersoid number density and a more uniform distribution of dispersoids for the lowest heating rate, as compared to the more rapid heating rates, for the alloy with 0.05 wt% Mn. For the alloy with 0.15 wt% Mn the number density increased with the heating rate. This is suggested to be due to particle coarsening as an effect of the low heating rate where the samples spend longer time in the furnace.

Abstract: Contrast experiment was developed on the semi-aerobic and anaerobic landfill treatment. Leachate nitrate nitrogen concentrations in different landfill layers spatially were monitored regularly in two landfill equipments, and variations and differences of leachate nitrate nitrogen concentration of different landfills were discussed. The results showed that differences on the variation characteristics of nitrate nitrogen concentration in space and time were obvious in the landfill treatments with different structures. In 73 weeks of monitoring period, nitrate nitrogen concentration in the middle and the lower layer of semi-aerobic landfill treatment was in turn stable within 55.40 mg/L and 40.80 mg/L; The concentration fluctuations in both layers were small in general. Nitrate nitrogen concentration decreased respectively to 9.26 mg/L, 6.82 mg/L and 4.69 mg/L at the 73th week from 28.51 mg/L, 4.44 mg/L and 5.85 mg/L at the initial landfill stage in the lower , middle and the upper layer of anaerobic landfill treatment. When degradation of the landfill treatments went into relatively stable stage, nitrate nitrogen concentration in the upper, middle and the lower layer of semi-aerobic landfill treatment was located respectively in 30-240 mg/L, 2.5-11.0 mg/L and 5.5-13.5 mg/L respectively, and the spatial distribution difference of nitrate nitrogen concentration in the upper layer of semi-aerobic landfill treatment was relatively big, but those of the middle and the lower layer were relatively small, and they were both lower than the upper layer. Nitrate nitrogen concentration in the upper, middle and the lower layer of anaerobic landfill treatment was located in 1.6-7.4 mg/L, 3.8-7.2 mg/L and 7.5-15 mg/L respectively, and showing a performance of spatial nitrate nitrogen concentration that was the lower layer> the middle layer >the upper layer. Under the experimental conditions, seim-aerobic landfill treatment was favorable to the nitrification and denitrification of leachate in contrast with the anaerobic landfill treatment.

Abstract: The concentrations of heavy metals (Cr, Cu, Ni, Pb and Mn) were determined using flame atomic absorption spectrophotometer after digested with four acids. The samples were collected from seven kinds of different functional areas in Taiyuan, China. The concentration of the heavy metals were found in Taiyuan is higher than the soil background values in Shanxi Province, which appeared different levels of accumulation. High concentrations of Cr, Ni, Mn were found in the samples from industrial area and Cu was noted from economic development area. The correlational analysis and principle component analysis showed that the heavy metals of surface dust in Taiyuan were mainly influenced by industrial activities.

Abstract: Soil samples from 6 sampling sites along 5 depths (0, 10, 20, 30, 40cm) were collected from an rural dumpsite in Hebei Province. The heavy metal (As, Cr, Cd, Pb, Cu, Zn) concentration were measured by inductively coupled plasma atomic absorption spectrometry (ICP/AES) in order to study the spatial distribution and assess their risk by the geoaccumulation index and potential ecological risk index. It was found that the mean concentrations of Cd, Pb, Cu were higher than the elemental background values in Hebei Province. The spatial distribution show that the longer stacking area had heavier heavy metal pollution in deeper soil due to long-term penetration of leachate and new stacking area had heavier pollution in surface soil. However, the geoaccumulation index and potential ecological risk index values show that most sites of the studied soils is in uncontaminated or low contaminated level. The potential ecological risk index values in the dumpsite were, in descending order, Cd > Cu > Pb > As > Cr > Zn, respectively, implying that Cd, Cu, Pb posed a higher hazard to human and ecosystem health. It was recommended that some measures were required to reduce heavy metal contents in soils caused by garbage dump.

Abstract: It take 4010 samples which have intercity travel between Guangzhou and Foshan under the background of urban integration as studying object and acquire travel information from internet investigation. It cross analyze the intercity travel characteristics which contain travel purpose, mode, frequency and cost and the travelers social attributes which include the career, age and revenue through the methods of Social Statistics and GIS spatial analysis. It also studies the changing of Guang-Fo intercity travel and the distributing characteristics of travel origins.

Abstract: ArcGIS analysis was applied to study the concentrations and spatial distribution characteristics of Cr and Ni in surface soil (0~20cm) of corn belt in Dehui—the typical area of black soil in Jilin province. The average concentrations of Cr and Ni were 49.85 mg·kg^-1 and 20.85 mg·kg^-1, which were both lower than the corresponding background value and thus in no pollution level. The trends for soil Cr and Ni were similar with higher concentrations trending N-S across the centre of the study area, while the other hotspots were located in the southwest of Dehui. There was prominent correlation between Cr and Ni in 0.01 level, indicating the close relationship of them. The method based on the geostatistical analysis in ArcGIS can exactly reflect the character of spatial distribution of heavy metals.

Abstract: By collecting the data of FDI on China seaport construction from 1991 to 2011, and using the nearest point coefficient and Gini coefficient, this paper quantitatively analyzed the spatial and temporal distribution of FDI on China Seaport Construction in three following periods: 1991-1997, 1991-2003 and 1991-2011. Statistics showed that temporal distribution of FDI on China seaport construction was relatively concentrated, and had very strong cyclical quality. Calculation results of the nearest point coefficient and Gini coefficient showed that respectively, the distribution of seaports invested by foreign was aggregated and the distribution of FDI in port groups was unbalanced in each period. But the aggregated and unbalanced degree experienced the same process that first got bigger and then became smaller.

Abstract: The main objectives were to investigate the concentrations of heavy metal in Guilin vegetable topsoils by conducting geostatistical analyses, including Kriging method assisted with GIS tool. These results will contribute to the management of regional environment. A total of one hundred and eighty-six samples of topsoils (0~20cm) were collected from all over Guilin, China. Concentrations of topsoil Cu, As, Ni, Zn, Pb and Cd in Guilin area were measured and contour maps were constructed to describe the metals’ spatial distribution. The concentrations of heavy metals in vegetable soil are in log-normal distribution, so the Geometric means of Cu, As, Ni, Zn, Pb and Cd are 28.30, 20.00, 23.97, 91.01, 36.76 and 0.62 mg/kg, respectively. Concentration of 6 heavy metals were comparable with background values of Guilin except Cd, but all of them were much lower than the second level of environmental quality standard for soil of China.