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| 1 | Topographical relief characteristics and its impact on population and economy:A case study of the mountainous area in western Henan,China显示文摘Topographical relief is a key factor that limits population distribution and economic development in mountainous areas.The limitation is especially apparent in the mountain?plain t「ansition zone.Taking the transition zone between the Qinling Mountains and the North China Plain(i.e.the mountainous area in western Henan Province)as an example and based on the 200-m resolution DEM data,we used the mean change-point analysis to determine the optimal statistical unit for topographical relief,and thereafter extracted the relief degree.Taking the 1:100,000 land use data,township population and county-level industrial data,population and economic spatial models were constructed,and 200?m resolution grid population and economic density maps were gen erated.Afterwards,statistical analysis was carried out to quantitatively reveal the impact of topographical relief on population and economy.In addition,the impacts of other topographical factors were discussed.The results showed the following.(1)The relief degree in western Henan is generally low,where 58.6%of the regional topography does not exceed half the height of a reference mountain(relative elevation W250 m).Spatially,the relief degree is high in the west while low in the east,and high in the middle while low in the north and south.There is a positive correlation between relief degree and elevation,and a much stronger correlation between relief degree and slope.(2)The linear fitting degree between the population and economic validation data and the corresponding simulation data are 0.943 and 0.909,respectively,indicating that the spatialized results can reflect the actual population and economic distribution.(3)The impact of topographical relief on population and economy was stronger than that of other topographical factors.The relief degree showed a good logarithmic fit relati on ship with population density(0.911)and economic density(0.874).Specifically,88.65%of the population lives in areas where the topographical relief is W0.5 and 88.03%of the gross regional product was from areas where the relief is W0.3.Compared with the population distribution,the economic development showed an obvious agglomeration trend towards low relief areas. | ZHANG Jingjing ZHU Wenbo ZHU Lianqi CUI Yaoping HE Shasha REN Han | 2019 | Journal of Geographical Sciences2019,29,4: | 8 |
| 2 | Determining the spatial distribution of soil properties using the environmental covariates and multivariate statistical analysis: a case study in semi-arid regions of Iran显示文摘Natural soil-forming factors such as landforms, parent materials or biota lead to high variability in soil properties. However, there is not enough research quantifying which environmental factor(s) can be the most relevant to predicting soil properties at the catchment scale in semi-arid areas. Thus, this research aims to investigate the ability of multivariate statistical analyses to distinguish which soil properties follow a clear spatial pattern conditioned by specific environmental characteristics in a semi-arid region of Iran. To achieve this goal, we digitized parent materials and landforms by recent orthophotography. Also, we extracted ten topographical attributes and five remote sensing variables from a digital elevation model(DEM) and the Landsat Enhanced Thematic Mapper(ETM), respectively. These factors were contrasted for 334 soil samples(depth of 0–30 cm). Cluster analysis and soil maps reveal that Cluster 1 comprises of limestones, massive limestones and mixed deposits of conglomerates with low soil organic carbon(SOC) and clay contents, and Cluster 2 is composed of soils that originated from quaternary and early quaternary parent materials such as terraces, alluvial fans, lake deposits, and marls or conglomerates that register the highest SOC content and the lowest sand and silt contents. Further, it is confirmed that soils with the highest SOC and clay contents are located in wetlands, lagoons, alluvial fans and piedmonts, while soils with the lowest SOC and clay contents are located in dissected alluvial fans, eroded hills, rock outcrops and steep hills. The results of principal component analysis using the remote sensing data and topographical attributes identify five main components, which explain 73.3% of the total variability of soil properties. Environmental factors such as hillslope morphology and all of the remote sensing variables can largely explain SOC variability, but no significant correlation is found for soil texture and calcium carbonate equivalent contents. Therefore, we conclude that SOC can be considered as the best-predicted soil property in semi-arid regions. | Mojtaba ZERAATPISHEH Shamsollah AYOUBI Magboul SULIEMAN JesusRODRIGO-COMINO | 2019 | Journal of Arid Land2019,11,4: | 5 |
| 3 | Evaluating the suitability of different terrains for sustaining human settlements according to the local elevation range in China using the ASTER GDEM显示文摘The topographical suitability assessment of human settlements(SAHS) creates a solid foundation for regional population distribution and socio-economic development. Local elevation range(LER) is an important factor that can be used to assess the suitability of different terrains for sustaining human settlements. However, current digital elevation model(DEM)-based LER products suffer from some challenges typically because of their subjectively selected neighborhood scales and coarser spatial resolution. In this study, we initially determined the optimal statistical window and then calculated the appropriate LER with the finer resolution data of the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global DEM(ASTER GDEM) products for China. Then, the appropriate LER was used to evaluate the topographical SAHS and its correlations with the national gridded population distribution(1 km × 1 km) in 2010. The results show that the optimal statistical window for calculating a 1 arc-second(about 30 m) resolution GDEM LER for China can be determined using a 51 × 51 grid unit(width × height) within a rectangular neighborhood, corresponding to an area of about 2.34 km^2. Secondly, the LER values in the southern and western China were greater than those of the north and east, showing a trend which consistently reflects the general spatial features of landforms. Finally, the relationship between GDEM LER and population density was highly correlated with the R^2 value of 0.81. It showed that 85.22% of the Chinese population was located in areas where the LER is lower than 500 m. The topographically suitable area within China decreased from the southeastern coastal zone towards the northwestern inland areas due to transition from plains and basins to plateaus and mountains. The total area of moderate to high suitable level was 423.84 × 10~4 km^2, or 44.15% of the total land area, with 88.17% of the national population. Our study demonstrates the usefulness of appropriate LER in evaluating the topographical SAHS as well as its significant impact on population distribution. | XIAO Chi-wei FENG Zhi-ming LI Peng YOU Zhen TENG Jia-kun | 2018 | Journal of Mountain Science2018,15,12: | 5 |
| 4 | A stage-specific cell-manipulation platform for inducing endothelialization on demand显示文摘Endothelialization is of great significance for vascular remodeling,as well as for the success of implanted vascular grafts/stents in cardiovascular disease treatment.However,desirable endothelialization on synthetic biomaterials remains greatly challenging owing to extreme difficulty in offering dynamic guidance on endothelial cell(EC)functions resembling the native extracellular matrix-mediated effects.Here,we demonstrate a bilayer platform with near-infrared-triggered transformable topographies,which can alter the geometries and functions of human ECs by tunable topographical cues in a remote-controlled manner,yet cause no damage to the cell viability.The migration and the adhesion/spreading of human ECs are respectively promoted by the temporary anisotropic and permanent isotropic topographies of the platform in turn,which appropriately meet the requirements of stage-specific EC manipulation for endothelialization.In addition to the potential of promoting the development of a new generation of vascular grafts/stents enabling rapid endothelialization,this stage-specific cell-manipulation platform also holds promise in various biomedical fields,since the needs for stepwise control over different cell functions are common in wound healing and various tissue-regeneration processes. | Qilong Zhao Juan Wang Yunlong Wang Huanqing Cui Xuemin Du | 2020 | National Science Review2020,7,3: | 3 |
| 5 | A STUDY ON TYPHOON MOVEMENT PARTⅡ: DYNAMICAL ROLE OF SMALL TOPOGRAPHY AND THE PLANETARY BOUNDARY LAYER显示文摘ASTUDYONTYPHOONMOVEMENTPARTⅡ:DYNAMICALROLEOFSMALLTOPOGRAPHYANDTHEPLANETARYBOUNDARYLAYER¥HeHaiyanandYangPingzhang(Departmentof... | 贺海晏 杨平章 | 1996 | Journal of Tropical Meteorology1996,2,2: | 1 |
| 6 | AUTOMATIC EXTRACTION OF VALLEY BOUNDARY FROM DEMS IN THE HILLY LOESS PLATEAU显示文摘As an important geomorphological divide in the hilly Loess Plateau, valley boundary plays a pivotal role in the construction of distributed models for studying the processes and mechanism of soil erosion, sediment transfer and runoffs within a watershed. In the past, this boundary manually interpreted from large scale maps and aerial photographs. In this paper, the authors first present a simple and practical definition for topographic structures unique to the highly dissected topography in the hilly Loess Plateau in DEMs; then define the valley boundary cells in a DEM with the following features: 1) they are most likely located on a concave slope, 2) these cells have the sharpest transition in slope, 3) those cells on the downward side of the valley boundary should have a slope gradient larger than 20° ,4) as the boundary of the entire valley in a basin valley boundary must be continuous; then devise an algorithm to automatically delineate valley boundary from DEMs and implement it in a computer. This algorithm was applied to detect drainage networks and the valley boundary in the Wangjiagou basin in the hilly loess area of Lishi County, Shanxi Province, China from a 10 m DEM. The extracted results are highly comparable to those manually interpreted from aerial photographs. | Ya-dong Qian Guo-nian Lu Zhong-ming Chen | 2000 | Chinese Geographical Science2000,10,3: | 0 |
| 7 | Diagnosis of the surface morphology of laser-ablated materials using the weightedDCT approach in laser speckle interferometry for application to plasma facing materials显示文摘To implement on-line, real-time monitoring for the surface morphology of Plasma-Facing Materials(PFMs) in tokamak, we developed a Laser Speckle Interferometry measurement approach. A laser ablation method was used to simulate the erosion process during Plasma-Wall Interactions in a tokamak. In the present investigation, we evaluated the results of laser ablation morphology changes on the surface of Mo material reconstructed by four different approaches(Flood-fill, Quality-guided, Discrete Cosine Transform(DCT) and Weighted-DCT). The morphology results measured by the weighted-DCT approach are very close to the measurement results from confocal microscopy with an average error rate within 7%. It is verified that the weighted-DCT algorithm has high accuracy and can efficiently reduce the influence of noise pollution coming from laser ablation, which is used as a proxy for erosion from plasma wall interaction. Additionally, the CPU computer time has been shortened. This is of great significance for the real-time monitoring of PFMs’ morphology in the Experimental Advanced Superconducting Tokamak(EAST) in the future. | 李元博 王宏北 崔晓倩 李树华 赵栋烨 丁洪斌 | 2019 | Plasma Science and Technology2019,21,9: | 0 |