Under the influence of anthropogenic and climate change,the problems caused by urban heat island(UHI)has become increasingly prominent.In order to promote urban sustainable development and improve the quality of human...Under the influence of anthropogenic and climate change,the problems caused by urban heat island(UHI)has become increasingly prominent.In order to promote urban sustainable development and improve the quality of human settlements,it is significant for exploring the evolution characteristics of urban thermal environment and analyzing its driving forces.Taking the Landsat series images as the basic data sources,the winter land surface temperature(LST)of the rapid urbanization area of Fuzhou City in China was quantitatively retrieved from 2001 to 2021.Combing comprehensively the standard deviation ellipse model,profile analysis and GeoDetector model,the spatio-temporal evolution characteristics and influencing factors of the winter urban thermal environment were systematically analyzed.The results showed that the winter LST presented an increasing trend in the study area during 2001–2021,and the winter LST of the central urban regions was significantly higher than the suburbs.There was a strong UHI effect from 2001 to 2021with an expansion trend from the central urban regions to the suburbs and coastal areas in space scale.The LST of green lands and wetlands are significantly lower than croplands,artificial surface and unvegetated lands.Vegetation and water bodies had a significant mitigation effect on UHI,especially in the micro-scale.The winter UHI had been jointly driven by the underlying surface and socio-economic factors in a nonlinear or two-factor interactive enhancement mode,and socio-economic factors had played a leading role.This research could provide data support and decision-making references for rationally planning urban layout and promoting sustainable urban development.展开更多
It is crucial to investigate the urban agglomerations spatio-temporal evolution patterns and driving factors for analyzing the urban spatial structure-functional division and promoting the coordinated development of u...It is crucial to investigate the urban agglomerations spatio-temporal evolution patterns and driving factors for analyzing the urban spatial structure-functional division and promoting the coordinated development of urban agglomerations.In this study,a novel vegetation-building-nighttime light-adjusted index(VBNAI)was established for rapid and effective mapping of urban construction land(UCL)in Central Plains Urban Agglomeration(CPUA),China during 2000–2020 based on Google Earth Engine(GEE)platform.Compared with traditional indices,VBNAI can significantly decrease the blooming effect,Normalized Difference Vegetation Index(NDVI)saturation,and soil background of nighttime light data.In addition,the urban expansion indices and standard deviation ellipse model were synthetically adopted to analyze the spatio-temporal evolution pattern of urban expansion.The gravity model and the geographically weighted regression model were employed to determine the spatial interaction forces and drivers of urban expansion,respectively.The results showed that the VBNAI index has obvious advantages in efficiency and accuracy to extract UCL with the overall accuracy of more than 91%.The UCL of CPUA had increased by 4489.84 km2 during 2000–2020 with the gravity center moving towards southeast continuously.From 2000 to 2010,the urban expansion was in a‘center-hinterland’pattern which had benefit from the favorable effect of the traffic shaft belt.During 2010–2020,the urban network structure had basically established.Urban expansion had been influenced by a variety of socio-economic and demographic factors,and the impact degree varied from region to region.This study could provide scientific references for facilitating the intensive utilization of urban resources and optimizing the spatial development pattern of urban agglomeration.展开更多
目的探讨超声引导下经外周置入中心静脉导管(peripherally inserted central catheter,PICC)在新生儿穿刺困难中的临床应用。方法选取2019年1月至2021年4月于昆明市儿童医院新生儿科同一组专业的PICC管理团队小组评估为穿刺困难的104例...目的探讨超声引导下经外周置入中心静脉导管(peripherally inserted central catheter,PICC)在新生儿穿刺困难中的临床应用。方法选取2019年1月至2021年4月于昆明市儿童医院新生儿科同一组专业的PICC管理团队小组评估为穿刺困难的104例新生儿为研究对象,将其随机分为观察组和对照组,每组各52例。对照组采取传统盲穿置管,观察组采取超声引导下置管,比较2组患儿在穿刺次数、留置时间、一次性穿刺成功率、一次性置管成功率、留置时间等方面的差异。结果观察组的平均穿刺次数以及置管时间均少于对照组;观察组一次性穿刺成功率、一次性置管成功率均高于对照组;观察组留置时间长于对照组;差异均有统计学意义(P<0.05)。观察组穿刺时周围组织损伤、经皮氧饱和度下降的发生率均低于对照组;观察组穿刺后维护期并发症的总发生率低于对照组;差异有统计学意义(P<0.05)。结论穿刺困难新生儿行PICC时,经超声引导,在穿刺过程中可有效减少穿刺次数及置管时间,提高一次性穿刺成功率及一次性置管成功率,并且增加了留置时间,值得临床推广。展开更多
城市群时空演变过程研究对优化城市群空间结构及促进城市间协调发展均具有重要意义。以1992—2013年DMSP/OLS夜间灯光数据为数据源,综合利用地理信息系统(geographic information system,GIS)空间分析技术、城市位序-规模法则、城市空...城市群时空演变过程研究对优化城市群空间结构及促进城市间协调发展均具有重要意义。以1992—2013年DMSP/OLS夜间灯光数据为数据源,综合利用地理信息系统(geographic information system,GIS)空间分析技术、城市位序-规模法则、城市空间扩展速率指数及标准差椭圆等方法对环渤海城市群时空演变过程进行研究,结果表明:①1992—2013年间,该城市群各城市夜间灯光总量均呈显著增长,整体增长率为135.89%;②随时间推移,该城市群中心城市对周边地区的辐射带动作用逐步增强,城市规模分布由不均衡状态向均衡状态转变;③该城市群空间扩展呈中心城市圈层化特征,演变格局表现为由西向东,由北向南的趋势,重心向西南方向偏移,空间范围呈扩张态势。研究可为环渤海及我国其他城市群时空演变研究提供方法借鉴与数据支持。展开更多
基金Under the auspices of the Social Science and Humanity on Young Fund of the Ministry of Education of China(No.21YJCZH100)the Scientific Research Project on Outstanding Young of the Fujian Agriculture and Forestry University(No.XJQ201920)+1 种基金the Science and Technology Innovation Special Fund Project of Fujian Agriculture and Forestry University(No.CXZX2021032)the Forestry Peak Discipline Construction Project of Fujian Agriculture and Forestry University(No.72202200205)。
文摘Under the influence of anthropogenic and climate change,the problems caused by urban heat island(UHI)has become increasingly prominent.In order to promote urban sustainable development and improve the quality of human settlements,it is significant for exploring the evolution characteristics of urban thermal environment and analyzing its driving forces.Taking the Landsat series images as the basic data sources,the winter land surface temperature(LST)of the rapid urbanization area of Fuzhou City in China was quantitatively retrieved from 2001 to 2021.Combing comprehensively the standard deviation ellipse model,profile analysis and GeoDetector model,the spatio-temporal evolution characteristics and influencing factors of the winter urban thermal environment were systematically analyzed.The results showed that the winter LST presented an increasing trend in the study area during 2001–2021,and the winter LST of the central urban regions was significantly higher than the suburbs.There was a strong UHI effect from 2001 to 2021with an expansion trend from the central urban regions to the suburbs and coastal areas in space scale.The LST of green lands and wetlands are significantly lower than croplands,artificial surface and unvegetated lands.Vegetation and water bodies had a significant mitigation effect on UHI,especially in the micro-scale.The winter UHI had been jointly driven by the underlying surface and socio-economic factors in a nonlinear or two-factor interactive enhancement mode,and socio-economic factors had played a leading role.This research could provide data support and decision-making references for rationally planning urban layout and promoting sustainable urban development.
基金Under the auspices of Social Science and Humanity on Young Fund of the Ministry of Education of China(No.21YJCZH100)the Scientific Research Project on Outstanding Young of the Fujian Agriculture and Forestry University(No.XJQ201920)+1 种基金the Science and Technology Innovation Special Fund Project of Fujian Agriculture and Forestry University(No.CXZX2021032)the Forestry Peak Discipline Construction Project of Fujian Agriculture and Forestry University(No.72202200205)。
文摘It is crucial to investigate the urban agglomerations spatio-temporal evolution patterns and driving factors for analyzing the urban spatial structure-functional division and promoting the coordinated development of urban agglomerations.In this study,a novel vegetation-building-nighttime light-adjusted index(VBNAI)was established for rapid and effective mapping of urban construction land(UCL)in Central Plains Urban Agglomeration(CPUA),China during 2000–2020 based on Google Earth Engine(GEE)platform.Compared with traditional indices,VBNAI can significantly decrease the blooming effect,Normalized Difference Vegetation Index(NDVI)saturation,and soil background of nighttime light data.In addition,the urban expansion indices and standard deviation ellipse model were synthetically adopted to analyze the spatio-temporal evolution pattern of urban expansion.The gravity model and the geographically weighted regression model were employed to determine the spatial interaction forces and drivers of urban expansion,respectively.The results showed that the VBNAI index has obvious advantages in efficiency and accuracy to extract UCL with the overall accuracy of more than 91%.The UCL of CPUA had increased by 4489.84 km2 during 2000–2020 with the gravity center moving towards southeast continuously.From 2000 to 2010,the urban expansion was in a‘center-hinterland’pattern which had benefit from the favorable effect of the traffic shaft belt.During 2010–2020,the urban network structure had basically established.Urban expansion had been influenced by a variety of socio-economic and demographic factors,and the impact degree varied from region to region.This study could provide scientific references for facilitating the intensive utilization of urban resources and optimizing the spatial development pattern of urban agglomeration.
文摘目的探讨超声引导下经外周置入中心静脉导管(peripherally inserted central catheter,PICC)在新生儿穿刺困难中的临床应用。方法选取2019年1月至2021年4月于昆明市儿童医院新生儿科同一组专业的PICC管理团队小组评估为穿刺困难的104例新生儿为研究对象,将其随机分为观察组和对照组,每组各52例。对照组采取传统盲穿置管,观察组采取超声引导下置管,比较2组患儿在穿刺次数、留置时间、一次性穿刺成功率、一次性置管成功率、留置时间等方面的差异。结果观察组的平均穿刺次数以及置管时间均少于对照组;观察组一次性穿刺成功率、一次性置管成功率均高于对照组;观察组留置时间长于对照组;差异均有统计学意义(P<0.05)。观察组穿刺时周围组织损伤、经皮氧饱和度下降的发生率均低于对照组;观察组穿刺后维护期并发症的总发生率低于对照组;差异有统计学意义(P<0.05)。结论穿刺困难新生儿行PICC时,经超声引导,在穿刺过程中可有效减少穿刺次数及置管时间,提高一次性穿刺成功率及一次性置管成功率,并且增加了留置时间,值得临床推广。
文摘城市群时空演变过程研究对优化城市群空间结构及促进城市间协调发展均具有重要意义。以1992—2013年DMSP/OLS夜间灯光数据为数据源,综合利用地理信息系统(geographic information system,GIS)空间分析技术、城市位序-规模法则、城市空间扩展速率指数及标准差椭圆等方法对环渤海城市群时空演变过程进行研究,结果表明:①1992—2013年间,该城市群各城市夜间灯光总量均呈显著增长,整体增长率为135.89%;②随时间推移,该城市群中心城市对周边地区的辐射带动作用逐步增强,城市规模分布由不均衡状态向均衡状态转变;③该城市群空间扩展呈中心城市圈层化特征,演变格局表现为由西向东,由北向南的趋势,重心向西南方向偏移,空间范围呈扩张态势。研究可为环渤海及我国其他城市群时空演变研究提供方法借鉴与数据支持。
