排序方式： 共有144条查询结果，搜索用时 15 毫秒
81.
山东省绿色发展水平绩效评价与驱动机制——基于17地市面板数据 总被引：6，自引：3，他引：3
构建绿色发展评价指标体系,并利用熵值法、全局莫兰指数、GWR模型等多种计量方法对2005~2016年山东省17地级市绿色发展水平时空分异特征与驱动机制进行了综合研究,结果表明：① 山东省绿色发展“自上而下”指令性特征比较突出,且依赖于物质消耗型规模增长,势必忽视经济要素横向转移反馈作用与产业集群效应;② 山东省绿色发展水平逐年递增,俱乐部收敛特征较为突出,但其年均增长率仅为1.77%反映了产业轻型化与清型化进程缓慢,绿色发展质量提升之路漫长而艰巨;③ 山东省绿色发展经历了空间依存关系不明显到明显的过程,且绿色发展水平存在明显的空间分异态势,两极化发展特征较为明显;④ 加入空间效应的空间加权回归模型更具有解释力,人均GDP、万人R&D人员数、人均固定资产投资等对于绿色发展水平的优化提升起到正向促进作用,第二产业增加值/第三产业增加值对于绿色发展回归系数呈现负相关,实际利用外资对于绿色发展回归系数有正有负。 相似文献
82.
Lili Huo Yuanchun Zou Xianguo Lyu Zhongsheng Zhang Xuehong Wang Yi An 《中国地理科学(英文版)》2018,28(2):325-336
Content and density of soil organic carbon(SOC) and labile and stable SOC fractions in peat mire soil in wetland, soybean field and rice paddy field reclaimed from the wetland around Xingkai Lake in Northeast China were studied. Studies were designed to investigate the impact of reclamation of wetland for soybean and rice farming on stability of SOC. After reclamation, SOC content and density in the top 0–30 cm soil layer decreased, and SOC content and density in soybean field were higher than that in paddy field. Content and density of labile SOC fractions also decreased, and density of labile SOC fractions and their ratios with SOC in soybean field were lower than that observed in paddy field. In the 0–30 cm soil layer, densities of labile SOC fractions, namely, dissolved organic carbon(DOC), microbial biomass carbon(MBC), readily oxidized carbon(ROC) and readily mineralized carbon(RMC), in both soybean field and paddy field were all found to be lower than those in wetland by 34.00% and 13.83%, 51.74% and 35.13%, 62.24% and 59.00%, and 64.24% and 17.86%, respectively. After reclamation, SOC density of micro-aggregates( 0.25 mm) as a stable SOC fraction and its ratio with SOC in 0–5, 5–10, 10–20 and 20–30 cm soil layers increased. SOC density of micro-aggregates in the 0–30 cm soil layer in soybean field was 50.83% higher than that in paddy field. Due to reclamation, SOC density and labile SOC fraction density decreased, but after reclamation, most SOC was stored in a more complex and stable form. Soybean farming is more friendly for sustainable SOC residence in the soils than rice farming. 相似文献
83.
Weiji Wang Ding Lyu Mosang Wang Kefeng Liu Jie Kong Xiujuan Shan Xianshi Jin 《海洋学报(英文版)》2020,39(12):76-81
This study provides new insights for the hatchery released Chinese shrimp (Fenneropenaeus chinensis), including proportion, dynamic migration route, after they were released into nature for stock enhancement using a new strategy quite different than ever. Chinese shrimp were sampled at 22 survey stations during two investigation voyages acrossing 74 survey stations in the Bohai Sea from July 16 to August 9 in 2015. Among 289 sampled individuals during the second voyage, totally 155 shrimps were identified as hatchery shrimp released into the Laizhou Bay at mid-May in 2015 based on finger-print of eight SSR (simple sequence repeats) markers, and the proportion of hatchery released shrimp in recapture samples were from 41.30%–85.71% in each station with an average value 53.63%, which verified a previous view point that up to 90% of autumn season Chinese shrimp landing in the Bohai Sea were composed of hatchery released. Meanwhile, the dynamic migration route of hatchery released shrimp revealed that part of released shrimp migrated heading northwest along the west coast of the Bohai Sea up to the Bohai Bay but just remained at the Laizhou Bay until over-wintering migration at mid-October when they initiate over-wintering migration. Present unnatural spring season shrimp fishing model cut the throat of spawner shrimp chance to swim back to their respective spawning plants at each spring, it still no chance to clarify whether the hatchery released shrimp could replenish to the reproduce population and complete a whole life cycle as same as their natural relatives. 相似文献
84.
基于GIS的雪灾风险区划 总被引：2，自引：0，他引：2
依据巴彦淖尔地区冬春季节降水少、年变率大的气候特点和易形成雪灾的量级指标进行雪灾风险区划。选取1971—2010年11月到次年3月,日降雪量大于等于3mm,并出现积雪和结冰现象为研究对象,分析了降雪量大于等于3mm的降雪日数和积雪深度大于等于5cm的积雪日数年代际变化,结合民政部门历史灾情记载、实地调查、农牧业现状以及各种基础资料数据与GIS技术,从致灾因子、脆弱性评估分析方面,在NOAA卫星遥感雪覆盖监测图像上,利用加权综合与层次分析法,构建雪灾判别模型,得出巴彦淖尔地区雪灾风险区划:雪灾最严重的地区为五原县大部、乌前旗南部和东北部部分区域、乌中旗东南和西南两区域、乌后旗的海力素附近大片区域。 相似文献
85.
气象服务满意度分析在公众气象服务满意度评价业务上起着非常关键的作用。针对我国31个省市的气象服务满意度现状,采用2010年全国公众气象服务评估调查数据,分别运用主成分分析法和熵值法进行分析,得到两种关于城市气象服务满意度的排序结果。但主成分分析法侧重考虑变量的相关性以及熵值法侧重考虑变量的不确定性,故将两种排序结果在通过一致性检验的基础上,运用集成综合评价法得到另外一种新的排序结果,介于以上两种结果之间。因此得到一个关于城市气象服务满意度的新认识,并给出提高气象服务满意度的建议。 相似文献
86.
中国主要城市技术创新影响环境污染的空间分异与机理 总被引：2，自引：0，他引：2
基于中国285个地级及以上城市的数据,利用空间自相关模型,在全域和局域尺度分析技术创新与环境污染的空间关联,在此基础上,使用地理加权回归模型分析技术创新对环境污染影响程度的地区差异,并借助地理探测器分析其影响机理.研究结果表明:①技术创新与环境污染均存在显著的空间集聚性,二者在全域尺度上存在正向的空间关联,在局域尺度上... 相似文献
87.
When pumping is conducted in confined aquifer inside excavation pit(waterproof curtain),the direction of the groundwater seepage outside the excavation changes from horizontal to vertical owing to the existence of the curtain barrier.There is no analytical calculation method for the groundwater head distribution induced by dewatering inside excavation.This paper first analyses the mechanism of the blocking effects from a close barrier in confined aquifer.Then,a simple equation based on analytical solution is proposed to calculate groundwater heads inside and outside of the excavation pit with waterproof curtain(hereafter refer to close barrier)in a confined aquifer.The distribution of groundwater head is derived according to two conditions:(i)pumping with a constant water head,and(ii)pumping with a constant flow rate.The proposed calculation equation is verified by both numerical simulation and experimental results.The comparisons demonstrate that the proposed model can be applied in engineering practice of excavation. 相似文献
88.
根据我国海洋综合气象监测装备建设网点不继扩大和加密的现状,依靠现有的卫星通信网络,利用其覆盖范围广、通信稳定、实时在线和维持经费等优势,设计一种基于卫星通信网络的海洋气象数据采集系统.介绍该系统的数据采集结构和功能,智能处理终端的硬件组成,硬件电路芯片选型与使用;介绍系统软件的控制和编制方法,简述在可视化编程语言Microsoft Visual Studi0 6.0集成包环境下开发海洋气象数据采集系统软件的步骤;讨论基于我国北斗卫星通信网络的海洋气象数据采集系统的实际应用情况. 相似文献
89.
利用NCEP1°×1°再分析资料,对2015年7月西太平洋洋面上台风"莲花""灿鸿""浪卡"三者共存期间的路径特征、强度变化及相互作用进行了分析。结果表明:1)台风"莲花"与"灿鸿"发生互旋,导致强度较弱的"莲花"路径发生逆时针转向;"灿鸿"与"浪卡"发生明显的相互作用。2)"莲花"的低层水汽通道在互旋过程中被"灿鸿"夺走,后者产生反馈气流补充前者;"浪卡"与"灿鸿"在对流层高层通过水汽"连体"通道进行水汽交换。3)与"莲花"互旋过程中"灿鸿"产生的反馈气流远比相互作用过程中"浪卡"对"灿鸿"的补充气流强,因此相互作用过程结束后"莲花"暖心与涡度继续维持,而"灿鸿"迅速衰弱。4)两个台风相互作用过程的水汽"连体"通道高度不同,台风"莲花"与"灿鸿"相互作用位于对流层低层,而台风"灿鸿"与"浪卡"相互作用发生在对流层高层。 相似文献
90.
基于标准化降水蒸散指数（SPEI）,利用淮北地区108个气象站逐月气温、降水观测资料,采用线性趋势、M K突变检验等方法,从不同时间尺度（年、季）和干旱程度（轻旱、中旱、重旱和特旱）分析了淮北地区1961—2015年干旱频率和时空变化特征。结果表明：淮北地区1961—2015年总体呈干旱略加强趋势,其中1998—2001年干旱发生最频繁,干旱强度、极端干旱及中等干旱的频次均呈增加趋势。2011年淮北地区干旱程度发生了突变性增强;20世纪90年代起淮北地区夏季经历了先湿后干的转变,2013年是夏季转向干旱化的突变点。秋冬两季是淮北地区发生干旱频率较高的季节。秋季干旱分布广、旱情最为严重,淮北地区北部是秋季干旱的高发区;冬季发生中旱以上干旱的地区分布较广,主要位于淮北地区内的安徽片西部和江苏片中部。春夏季发生高频率干旱的区域相对较小。 相似文献