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81.
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   
82.
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   
83.
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   
84.
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   
85.
The Xinqiao deposit is one of several polymetallic deposits in the Tongling ore district. There are two types of mineralization in the Xinqiao: skarn-type and stratiform-type. The skarn-type mineralization is characterized by iron oxides such as magnetite and hematite, whereas stratiform-type mineralization is characterized by massive sulfides with small amounts of magnetite and hematite. We defined three types of ores within the stratiform-type mineralization by the mineral assemblages and ore structures. Type I ore is represented by magnetite crosscut by minor calcite veins. Type II is a network ore composed of magnetite and crosscutting pyrite. Type III is a massive ore containing calcite and hematite. Type I magnetite is characterized by highly variable trace element content, whereas Type II magnetite has consistently higher Si, Ti, V, and Nb. Type III magnetite contains more In, Sn, and As than the other two types. Fluid–rock interaction, oxygen fugacity (fO2), and temperature (T) are the main factors controlling element variation between the different magnetite types. Type I magnetite was formed by more extensive fluid–rock interaction than the other two types at moderate fO2 and T conditions. Type II magnetite is thought to have formed in relatively low fO2 and high-T environments, and Type III in relatively high fO2 and moderate-T environments. Ca?+?Al?+?Mn and Ti?+?V discrimination diagrams show that magnetite in the Xinqiao deposit is hydrothermal in origin and is possibly linked with skarn.  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  
辛晓华  吕拉昌 《地理科学》2021,41(1):129-139
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.
马艳军  吕爽  刘一谦  杨涛 《气象科技》2013,41(6):1057-1060
在深入剖析SMS (Supervisor Monitor Scheduler)技术架构的基础上,分析了GRAPES (Global and Regional Assimilation and Prediction Systesm)数值预报的特点,并对GRAPES传统运行技术和基于SMS技术的运行流程做了对比。运用SMS技术构建了客户端/服务器结构的GRAPES数值预报作业自动化系统,对GRAPES数值预报模式运行的流程做了详尽的划分,将功能类似GRAPES模式的模块组合在一起,在实施过程中将复杂的单一模块拆分成多个任务,把单个任务的功能简单化,以图形化界面直观的显示模式运行流程,实现了GRAPES预报模式作业流程的自动化,极大的提高GRAPES模式业务运行能力,保证模式运行的可靠性和时效性。  相似文献   
88.
以子长矿区内分布的300余组钻孔数据为基础,研究了陕北三叠纪煤田煤炭资源的物理化学性质,按照《煤中焦油含量分级》(MT/T1179—2019),划分了中油产率煤(7.0%<ω(Tard)<12.0%)和高油产率煤(12.0%<ω(Tard)<15.0%)的分布范围,预测了中—特高油产率煤的资源量。研究了矿区主采煤层3号煤层和5号煤层的煤质、沉积环境、变质程度等,认为矿区内中—特高油产率煤具一低两高的特征:镜质体反射率高(0.61%~0.83%)、变质程度低、挥发分高(35.78%~45.64%),认为成煤环境及变质程度是影响煤层富油的关键因素,研究区内5号煤层的焦油产率略高于3号煤层。  相似文献   
89.
吕承超  邵长花 《地理科学》2021,41(5):768-776
基于2003-2017年中国30个省份的数据,探究城市生活垃圾处理能力的时空格局,并构建动态面板数据模型实证检验中国城市生活垃圾处理能力的影响因素.研究结果表明,考察期内城市生活垃圾处理能力存在空间发展不平衡问题;进一步利用Dagum基尼系数测算城市生活垃圾处理能力的空间差距并将其进行分解,其中,东部地区的地区内差距最...  相似文献   
90.
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 i...  相似文献   
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