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611.
通过对高原地区一次强对流天气过程的天气形势、物理量、雷达回波强度等资料的综合分析得出,高海拔地区雹云演变有初生、发展、成熟、减弱四个阶段,回波由弱、零散、豆点状、无组织的对流单体变为强、组织有序的飑线,回波中心强度达到60dbz以上,回波顶高度超过12.0km,50dbz强回波上界超过8km. 相似文献
612.
Several cryptotephra layers that originate from Icelandic volcanic eruptions with a volcanic explosivity index (VEI) of ≤ 4 and tephra volumes of < 1 km3 have previously been identified in Northern Europe, albeit within a restricted geographical area. One of these is the Hekla 1947 tephra that formed a visible fall-out in southern Finland. We searched for the Hekla 1947 tephra from peat archives within the previously inferred fall-out zone but found no evidence of its presence. Instead, we report the first identification of Hekla 1845 and Hekla 1510 cryptotephra layers outside of Iceland, the Faroe Islands, Ireland and the UK. Additionally, Hekla 1158 tephra was found in Finland for the first time. Our results confirm that Icelandic eruptions of moderate size can form cryptotephra deposits that are extensive enough to be used in inter-regional correlations of environmental archives and carry a great potential for refining regional tephrochronological frameworks. Our results also reveal that Icelandic tephra has been dispersed into Finnish airspace at least seven times during the past millennium and in addition to a direct eastward route the ash clouds can travel either via a northerly or a southerly transport pathway. 相似文献
613.
Natural Hazards - The past few years have seen the raise of unmanned aerial vehicles (UAV) in geosciences for generating highly accurate digital elevation models (DEM) at low costs, which promises... 相似文献
614.
615.
东北三省流动人口居留意愿的空间差异及影响因素 总被引:2,自引:2,他引:0
基于2015年流动人口动态监测数据,综合运用空间自相关分析,趋势面分析等技术,结合二元Logistic回归模型,对东北三省流动人口居留意愿的空间分布和影响因素特征展开研究。主要发现:① 东北三省流动人口居留意愿呈现出“北高南低,东高西低”的空间格局特征,南北方向上的分异比东西方向大;② 流动人口居留意愿在空间上属于随机分布,齐齐哈尔市和黑河市位于高-高集聚区,哈尔滨市位于低-高集聚区。随着城市规模的增加,流动人口居留意愿呈现出先升后降的特征;③ 个体因素方面,农业户口流动人口、在婚流动人口、高学历流动人口、“80后”流动人口的居留意愿更强;④ 经济特征方面,收入与住房支出分别对居留意愿产生正向和负向影响;⑤ 社会因素方面,流入时间越长、职业类别为“专业技术及办事人员”与“商业服务人员”、就业身份为雇主、参加城镇职工医疗保险的流动人口居留意愿更强。 相似文献
616.
Relationship between economic growth and water environmental quality of Anshan city in Northeast China 总被引:1,自引:0,他引:1
Based on the decomposition model of environmental quality and univariate regression model, the relationships of industrial wastewater drainage with economic scale, economic structure, and technological level in Anshan, a mining city in Northeast China, were studied. The results showed that, due to scale effect, the drainage of three important industrial wastewater pollutants (COD, NH3-N and petroleum) increased 8505t, 671t and 384t, respectively, and due to structure effect, those pollutants drainage increased 3996t, 174t and 120t from 2001 to 2006. While due to technological effect, the drainage of COD, NH3-N and petroleum reduced 4452t, 458t and 331t, and due to cross effect, those pollutants drainage reduced 7270t, 575t and 476t simultaneously. Meantime, the relationships between household consumption structure and domestic sewage discharge were analyzed, and domestic sewage discharges in different income levels were also compared. The results showed that, the domestic sewage discharges would increase 376t with 1000 yuan (RMB) increased in the traffic and communication consumption, and they would be 344t, 219t, 428t, 1873t, respectively, in housing consumption, food consumption, medical consumption, miscellaneous commodity consumption. The proportion of domestic sewage discharge increased for high income residents significantly, but reduced for lower income residents. The industrial wastewater pollutants drainage tends to be reduced by technical progress, while domestic sewage discharge will be a more important factor for urban water environment quality. 相似文献
617.
��ά����ɨ�����ֱ���Զ���ȡ�㷨�о� 总被引:1,自引:1,他引:0
???????????????д???????????????????????????????????н??????????????????Щ?????????????????????????д?????????????????????Ч????????????????????????е??????????????RANSAC????????????н???????????????????Ч???????????????н????????????????????????????????????????????????????????????????????????????????????? 相似文献
618.
An energy conversion system based on deep-sea pressure 总被引:1,自引:0,他引:1
A novel seawater pressure energy conversion system that utilizes seawater pressure to generate electricity has been studied in this paper. The energy conversion system utilizes the pressure difference between the pressurized seawater and the empty pressure container to drive hydraulic motor and the coaxially coupled generator to generate electric power. The output electric energy is recorded by the data logger throughout the process. In the current study, technical analysis is performed with the emphasis on conversion efficiency between seawater pressure energy and output electric energy. The analysis is conducted at various pressure differences through the throttle valve so as to obtain maximum conversion efficiency. Research shows that the optimum pressure difference through the throttle valve and the maximum conversion efficiency can be theoretically calculated when the properties of the conversion system are given. Simulation results have demonstrated the influence of pressure difference on conversion efficiency. The test apparatus has been designed, built and tested in 2004. It successfully generated electric energy of approximately 0.85 kW h at the depth of 2400 m with empty pressure container's holding capacity of 200 L in the voyage “DY105-16” in South China Sea on June 12, 2004. The actual conversion efficiency from seawater pressure energy to electric energy reaches as high as 63.8% which is attractive for underwater equipments. The success of the experiment has tested the feasibility of utilizing seawater pressure energy and brings a new power supply way for long-term in-situ underwater equipments. 相似文献
619.
???GMDH??????????????????????????????????????????????????ɡ??м???????????????????????и??????????Matlab?????????????????????GMDH????????????????????????????У????????????????????????BP?????????GMDH??????????????????б????ó?????:?????GMDH???????н???????????????????н?????? 相似文献
620.
简要介绍了江苏省矿产资源形势、开发现状和存在的主要地质环境问题.介绍了<江苏省矿产资源管理条例>的立法背景、主要内容和重要意义.提出在当前形势下,认真学习、贯彻实施<条例>,应抓好5个方面的工作. 相似文献