地浸采铀工艺钻孔施工与成建井技术现状及改进建议     

李博  刘晓阳  胡柏石  秦昊 《铀矿地质》2017,(4):252-256

地浸法采铀是铀矿开采的重要方法,地浸工艺钻孔作为溶浸液进入与抽出矿层的通道,在地浸采铀工艺过程中发挥着重要作用。文章介绍了国内地浸采铀工艺钻孔施工与成建井技术现状,针对存在问题,对钻探设备、钻进工艺和成井工艺提出了改进建议。  相似文献   

中国地质大数据研究现状   总被引：4，自引：0，他引：4  

陈建平  李靖  谢帅 《江苏地质》2017,41(3):353-366

地质大数据应用研究是国家大数据战略的组成部分。地质学属于数据密集型学科,与地球科学面临的问题息息相关。已经收集的和将要收集的大量数字国土相关数据,由于科学研究的需要,正在不断加以检验和扩充,并已更好地应用与服务于人类活动。重点介绍了国内外大数据研究现状及国家大数据战略,并从地质大数据的定义、特点、产生途径、技术架构等方面剖析国内外地质大数据的研究现状。将目前及未来地质大数据的发展研究方向分为地质大数据发现、地质大数据梳理、地质大数据存储、地质大数据分析、地质大数据应用5个方面。  相似文献   

Role of environmental factors in affecting macrophyte dominance in transitional environments: The Italian Lagoons as a study case          下载免费PDF全文

Adriano Sfriso  Alessandro Buosi  Chiara Facca  Andrea A. Sfriso 《Marine Ecology》2017,38(2)

One of the main challenges to facilitate the classification of water bodies is to identify direct relationships between anthropogenic pressures and the behavior of biological organisms such as macrophytes in different environments including transitional areas. The investigation of many lagoons and ponds described here shows that macrophyte variables and the community composition have strong and univocal relationships with ecological parameters that are a measure of anthropogenic pressure on the ecological status of water bodies. The areas surveyed represent about 78% of the Italian transitional waters (169 sites sampled both in spring and fall). Anthropogenic impacts affect the availability of nutrients in the water column and surface sediments, causing changes in water transparency and phytoplankton concentration (as chlorophyll‐a [Chl‐a]) that act as the main drivers of variation for macrophyte assemblages, changing species dominance and the conditions that govern their presence or absence. The response of macrophytes to anthropogenic pressure is quite similar in all the examined transitional environments, even when the basin morphology, species richness and composition are different. Some taxa and species assemblages are so sensitive to environmental changes that monitoring them can be considered the most suitable and rapid method for assessing the quality of the environment they inhabit.  相似文献   

Recommendations for developing and applying genetic tools to assess and manage biological invasions in marine ecosystems     

《Marine Policy》2017

The European Union’s Marine Strategy Framework Directive (MSFD) aims to adopt integrated ecosystem management approaches to achieve or maintain “Good Environmental Status” for marine waters, habitats and resources, including mitigation of the negative effects of non-indigenous species (NIS). The Directive further seeks to promote broadly standardized monitoring efforts and assessment of temporal trends in marine ecosystem condition, incorporating metrics describing the distribution and impacts of NIS. Accomplishing these goals will require application of advanced tools for NIS surveillance and risk assessment, particularly given known challenges associated with surveying and monitoring with traditional methods. In the past decade, a host of methods based on nucleic acids (DNA and RNA) analysis have been developed or advanced that promise to dramatically enhance capacity in assessing and managing NIS. However, ensuring that these rapidly evolving approaches remain accessible and responsive to the needs of resource managers remains a challenge. This paper provides recommendations for future development of these genetic tools for assessment and management of NIS in marine systems, within the context of the explicit requirements of the MSFD. Issues considered include technological innovation, methodological standardization, data sharing and collaboration, and the critical importance of shared foundational resources, particularly integrated taxonomic expertise. Though the recommendations offered here are not exhaustive, they provide a basis for future intentional (and international) collaborative development of a genetic toolkit for NIS research, capable of fulfilling the immediate and long term goals of marine ecosystem and resource conservation.  相似文献   

The best catch data that can possibly be? Rejoinder to Ye et al. “FAO's statistic data and sustainability of fisheries and aquaculture”     

《Marine Policy》2017

Here we reply to a commentary by Ye et al. (Mar. Policy 2017; Ye et al.) on our article (Pauly and Zeller, 2017 [2]) commenting on FAO's interpretation of current fisheries trends in SOFIA 2016 (The State of World Fisheries and Aquaculture). We show how arguments such as FAO's catch statistics being “the best they can possibly be”, and other manifestations of FAO's difficulties in constructively engaging with comments compromises FAO's stated goal to engage with academia and civil society. This is particularly serious in an age where the value of an open scientific discourse is increasingly under threat, as is the food security of many poor countries in which fish supplied by domestic fisheries constitutes a strong component of local diets.  相似文献   

Reassessing the invasion of South African waters by the European shore-crab Carcinus maenas     

CA Mabin  JRU Wilson  JJ Le Roux 《African Journal of Marine Science》2017,39(3):259-267

The European shore-crab Carcinus maenas has been present in South Africa since 1983. Despite this species’ international reputation as a biological invader, its distribution in this region has only been considered by three outdated ‘snapshot surveys.’ The present study is the most comprehensive to date, providing an update on the species’ range and the first temporal assessment of its abundance and demographics. Along South Africa's Cape Peninsula and surrounding areas, C. maenas was absent from 12 intertidal sites surveyed, except for Sea Point, and no crabs were found during subtidal surveys along the open coastline. Subtidal harbour populations were recorded in the Cape Town harbours of Table Bay and Hout Bay (previously estimated as comprising approximately 164 200 and 6 500 individuals, respectively). Table Bay was surveyed monthly for one year, using baited traps, crab condos and postlarvae settlement collectors, to assess size distributions and reproductive seasonality of the crab. Reproductive females were recorded throughout most of the year. These results suggest that the harbour populations could be targeted by control programmes, but provide no strong evidence to support the initiation of management action during a particular season. The lack of detection of postlarval settlement, even among well-established populations, suggests this will not be a useful monitoring tool for detecting incursions.  相似文献   

苍南沿浦湾浅海养殖区水质质量评价          下载免费PDF全文

柯爱英  黄振华  蔡景波  曾国权  吴越  陈坚  范正利 《应用海洋学学报》2017,36(3):365-371

根据2013~2015年对沿浦湾浅海养殖区的水质进行的监测与分析资料,采用富营养化指数法和有机污染指数法对该海域海水营养状况和有机污染状况进行了评价.结果表明,该养殖区海水的溶解氧(DO)和化学需氧量(COD)含量符合国家二类海水水质标准,超过二类标准的指标为无机氮(DIN)、活性磷酸盐(PO_4~(3-)-P)和石油类.该养殖区春、冬两季水质指标超标情况较为明显,春季超标指标为无机氮和石油类,冬季超标指标为无机氮和活性磷酸盐.该养殖区的富营养化程度日趋严重,而有机污染程度总体不高.  相似文献   

钍射气（~（220）Rn）及其子体的研究现状与展望     

邱国华 《国外铀金地质》2010,(2):111-119

对钍射气220Rn及其子体的来源、影响因素、测量方法、剂量评价和防治措施作了概括性的介绍与展望。环境中220Rn的来源主要有建材和地质。220Rn的影响因素包括土壤中232Th的含量、建筑材料类别与性状、建筑物的通风条件、离墙和地面距离、季节、地表γ辐射水平等。根据测量原理的不同,220Rn测量可以分为滤膜法、闪烁室法、固体核径迹法、活性炭吸附法、半导体探测法和化学方法等。220Rn子体比220Rn对剂量的贡献更加重要。220Rn防治措施包括：建材选择、增加室内空气的流动、加强通风和阻断地基中的钍射气220Rn来源等。  相似文献   

地下水数值计算与应用研究进展综述   总被引：4，自引：0，他引：4       下载免费PDF全文

王浩  陆垂裕  秦大庸  桑学锋  李扬  肖伟华 《地学前缘》2010,17(6):1-12

地下水数值计算是研究分析地下水各种问题的重要手段。文中对近年来地下水数值模拟计算相关方法研究进展、地下水数值模拟工作程序的方法论、地下水数值模拟的参数反演方法、国际流行的地下水数值模型及软件平台、目前国内地下水数值模型的相关应用等几个方面进行了综述,力图从相对全面的角度认识当前地下水计算技术的发展。在回顾地下水以上研究进展的基础上,对现代信息技术在地下水数值计算技术中的积极促进作用、地下水更深入和复杂规律的研究、地下水研究与其他学科之间的综合集成和协同互补等发展趋势进行了探讨,为相关研究人员提供一定的参考。  相似文献   

世界页岩气勘探开发现状及对中国的启示     

李世臻  乔德武  冯志刚 《地质通报》2010,29(5):918-924

页岩气是一种潜在资源量巨大的非常规天然气资源,具有开采技术要求高、开采寿命长、稳产周期长的特点。近些年来,严峻的能源紧张形势和能源价格的快速增长,使页岩气资源在全世界受到了广泛的重视。回顾了美国页岩气勘探开发的历史,总结了美国的页岩气发育情况,跟踪了世界其他地区(加拿大、欧洲)包括中国页岩气研究的最新进展情况。根据前人的资料,认为中国南方海相页岩和北方盆地的湖相页岩具有巨大的页岩气资源潜力。鉴于页岩气是一种非常规能源,对其研究具有重大的现实意义,建议中国相关部门加大研究投入力度,尽快开展页岩气资源战略调查和选区研究工作,加强技术攻关创新、引进和国际合作,探讨中国现实国情下的页岩气相关政策,以早日实现页岩气在中国的商业性开发,促进经济快速发展。  相似文献