维普中文期刊产品整合服务
2篇 您的检索式:关键字=Structure variations
    题名 作者 年代 出处 被引量
1Regional Scale Seismological Investigation on the Continent Crust Using Airgun Sources——A Perspective Review显示文摘The investigations on the structure and temporal variations of the continent crust have been the long-lasting topics of seismology. The artificial sources play the most important role in these studies for their well-known locations and occur times among all the sources producing elastic waves,so that precise results are obtained. In past decades,we have successfully excited the airgun sources in on-land water bodies such as reservoirs,expanding their applications in marine seismology. Large volume airguns have been used to produce low frequency signals which can travel hundreds of kilometers after stacking,providing a source connecting the exploration seismology and traditional seismology at regional scale. In this review,we introduce the changes through which we turn the airgun into scientific instruments by experiments. We also present the advances on imaging the continental crust structure and monitoring the velocity variations using the highly repeatable signals emitted by airgun sources. The potential applications such as imaging the subsurface of urban areas and high resolution illuminating of mines are proposed and the challenges for further investigations are also discussed.Wang Weitao Wang Baoshan Jiang Shengmiao Hu Jiupeng Zhang Yuansheng 2018Earthquake Research in China2018,32,3:5
2Decadal variations in the community status of economically important invertebrates in the Bohai Sea显示文摘With the decline of fish stocks,the proportions of economically important invertebrates like crustaceans and cephalopods have increased in the Bohai Sea.The community structure and trophic level of economically important invertebrates were analyzed using the bottom trawl survey data collected by the Yellow Sea Fisheries Research Institute in the Bohai Sea in May and August of 1958–1959,1982,1992–1993,2004,2009 and 2015.A total of 37 species of economically important invertebrates,belonging to 5 orders,24 families,were captured.The biomass densities of economically important invertebrates in the Bohai Sea displayed an overall downward trend from 1982 to 2015.Oratosquilla oratoria and Loligo spp.were the most dominant species in the past 30 years,the biomass proportion of O.oratoria increased gradually in both May and August from 1982 to 2015.Moreover,biodiversity indices of economically important invertebrates in the Bohai Sea appeared to decline from 1982 to 2004 and then increased in 2015.Similarly,the mean trophic level of economically important invertebrates declined from 1982 to 2004 and increased slightly in 2015.Overall,although the proportions of invertebrates have increased,the biomass densities in the Bohai Sea have displayed an overall downward trend from 1982 to 2015.The increases in the biodiversity and trophic level of economically important invertebrates after the 2000s,possibly benefit from stock enhancement projects implemented by governments at different levels and national fishery management measures such as the“double-control”of the total number and engine power of fishing vessels and summer moratorium of fishing.Qiang Wu Lisha Guan Zhongyi Li Xiujuan Shan Xianshi Jin 2019Acta Oceanologica Sinica2019,38,10:3
返回顶部 每页显示:
共1页 首页 上一页 第1页 下一页 末页 /1 跳转

网站首页 | 关于我们 | 联系我们 | 产品服务 | 客服中心 | 广告服务 | 版权声明 | 网站联盟 | 友情链接 | 售卡网点

版权所有© 渝B2-20050021-1 渝公网安备 50019002500403号 违法和不良信息举报中心

互联网出版许可证 新出网证(渝)字10号 全国400电话 - 免长途话费