Seamount accretion is one of the most significant accretionary orogenic processes in the Central Asian Orogenic Belt,but there are few paleo-seamounts reported from and debate on the tectonic evolution of the Junggar ...Seamount accretion is one of the most significant accretionary orogenic processes in the Central Asian Orogenic Belt,but there are few paleo-seamounts reported from and debate on the tectonic evolution of the Junggar Ocean still exists.In this study,we present geochronological,mineralogical,geochemical and isotopic data for basalts from the Chagantaolegai ophiolitic mélanges in Junggar.Zircon U-Pb dating on one basalt yielded a weighted mean^(206)Pb/^(238)U age of 469±7 Ma,which suggests that it formed in the Middle Ordovician.All rock samples belong to alkaline basalt and show similar geochemical characteristics,displaying high TiO_(2)(~3 wt%),(La/Yb)N(17.6–19.0),ΣREE(232–289 ppm)and enrichment in Nb and Ta,which implies an ocean island basalt(OIB)affinity.Based upon positiveεN d(t)(+4.16 to+4.23),ΔNb(0.20–0.22)and low initial^(87)Sr/^(86)Sr(0.70425 to 0.70452)and Zr/Nb(3.35–3.57),we suggest that the Chagantaolegai OIB samples were likely derived from a fertile mantle source related to plume.The OIB rock assemblage,chert and marble in the southern part of the Chagantaolegai ophiolitic mélange indicates that a Middle Ordovician seamount was accreted to the Boshchekul-Chingiz arc due to the northward subduction of the Junggar-Balkhash Ocean.展开更多
This paper proposed a method for blind estimation of underwater channels in shallow water environment by using received data at a single hydrophone or from single beam. First, the received signal is used for source si...This paper proposed a method for blind estimation of underwater channels in shallow water environment by using received data at a single hydrophone or from single beam. First, the received signal is used for source signal reconstruction by means of signal-dependent TF （Time-Frequency） distribution, in association with instantaneous frequency estimation and TF inversion. Then the shallow-water channel estimation is achieved via WRELAX technique by use of the received signal and the estimated source signal. Finally, the results of numerical simulation and experimental test from real data taken in South China Sea trial have proved satisfactory. It is shown that the proposed method is useful for underwater channel estimation.展开更多
目的:了解脓毒症的研究现状和发展趋势,为该领域后续研究提供参考依据。方法:在Web of Science数据库检索脓毒症相关文献,使用科学引文索引扩展版(Science Citation Index Expanded,SCI-E)提取并分析数据,纳入文献类型为论著。对文献概...目的:了解脓毒症的研究现状和发展趋势,为该领域后续研究提供参考依据。方法:在Web of Science数据库检索脓毒症相关文献,使用科学引文索引扩展版(Science Citation Index Expanded,SCI-E)提取并分析数据,纳入文献类型为论著。对文献概况、国家和地区、机构、作者、文献来源出版物、文献研究方向、被引频次、影响因子、H指数和关键词等进行分析。结果:共纳入Web of Science数据库2010—2020年发表的脓毒症相关文献10965篇,美国发文量居首位(3318篇,30.260%),中国发文量居第2位(2404篇,21.924%);发文量最多的机构为匹兹堡大学(222篇,2.025%);发文量居首位的作者为荷兰阿姆斯特丹大学的Tom van der Poll(89篇,0.812%);脓毒症相关文献涉及的主要学科为普通内科学(2872篇,26.192%)、免疫学(1171篇,10.679%)、实验医学(963篇,8.782%)、外科学(887篇,8.089%)和儿科学(819篇,7.469%)等。脓毒症相关文献刊发数量居前10位的期刊2019年影响因子平均为5.252,刊发数量占此研究检索结果的21.61%(2369/10965)。此研究检索结果中,美国的H指数为124,文献总被引用114594次,平均每项被引33.78次,H指数和被引频次明显高于其他国家。VOSviewer软件分析结果表明,脓毒症相关文献的关键词主要集中于"疾病相关""发病机制相关""诊治相关""实验研究相关""预后相关"等。结论:2010—2020年脓毒症相关文献发文量以美国、中国和德国最多,其中中国发文量增速最快。近十余年,中国脓毒症相关文献总量位居世界第2位,且中国2020年单年发文量已超过美国跃居全球首位,但文献质量与西方国家文献仍存在较大差距。展开更多
基金supported by the National Science Foundation of China(Grant No.41672217)the Fundamental Research Funds for the Central Universities(Grant No.N170104022)the State Scholarship Fund(Grant No.201806085034)。
文摘Seamount accretion is one of the most significant accretionary orogenic processes in the Central Asian Orogenic Belt,but there are few paleo-seamounts reported from and debate on the tectonic evolution of the Junggar Ocean still exists.In this study,we present geochronological,mineralogical,geochemical and isotopic data for basalts from the Chagantaolegai ophiolitic mélanges in Junggar.Zircon U-Pb dating on one basalt yielded a weighted mean^(206)Pb/^(238)U age of 469±7 Ma,which suggests that it formed in the Middle Ordovician.All rock samples belong to alkaline basalt and show similar geochemical characteristics,displaying high TiO_(2)(~3 wt%),(La/Yb)N(17.6–19.0),ΣREE(232–289 ppm)and enrichment in Nb and Ta,which implies an ocean island basalt(OIB)affinity.Based upon positiveεN d(t)(+4.16 to+4.23),ΔNb(0.20–0.22)and low initial^(87)Sr/^(86)Sr(0.70425 to 0.70452)and Zr/Nb(3.35–3.57),we suggest that the Chagantaolegai OIB samples were likely derived from a fertile mantle source related to plume.The OIB rock assemblage,chert and marble in the southern part of the Chagantaolegai ophiolitic mélange indicates that a Middle Ordovician seamount was accreted to the Boshchekul-Chingiz arc due to the northward subduction of the Junggar-Balkhash Ocean.
基金This work was supported by the National Natural Science Foundation of China(60472073)(10304015)and by the Doctor Research Foundation of Ministry of Education of China(20020699010)by the Natural Science Fundamental Research Foundation of Shaanxi province(2005F40).
文摘This paper proposed a method for blind estimation of underwater channels in shallow water environment by using received data at a single hydrophone or from single beam. First, the received signal is used for source signal reconstruction by means of signal-dependent TF （Time-Frequency） distribution, in association with instantaneous frequency estimation and TF inversion. Then the shallow-water channel estimation is achieved via WRELAX technique by use of the received signal and the estimated source signal. Finally, the results of numerical simulation and experimental test from real data taken in South China Sea trial have proved satisfactory. It is shown that the proposed method is useful for underwater channel estimation.
文摘目的:了解脓毒症的研究现状和发展趋势,为该领域后续研究提供参考依据。方法:在Web of Science数据库检索脓毒症相关文献,使用科学引文索引扩展版(Science Citation Index Expanded,SCI-E)提取并分析数据,纳入文献类型为论著。对文献概况、国家和地区、机构、作者、文献来源出版物、文献研究方向、被引频次、影响因子、H指数和关键词等进行分析。结果:共纳入Web of Science数据库2010—2020年发表的脓毒症相关文献10965篇,美国发文量居首位(3318篇,30.260%),中国发文量居第2位(2404篇,21.924%);发文量最多的机构为匹兹堡大学(222篇,2.025%);发文量居首位的作者为荷兰阿姆斯特丹大学的Tom van der Poll(89篇,0.812%);脓毒症相关文献涉及的主要学科为普通内科学(2872篇,26.192%)、免疫学(1171篇,10.679%)、实验医学(963篇,8.782%)、外科学(887篇,8.089%)和儿科学(819篇,7.469%)等。脓毒症相关文献刊发数量居前10位的期刊2019年影响因子平均为5.252,刊发数量占此研究检索结果的21.61%(2369/10965)。此研究检索结果中,美国的H指数为124,文献总被引用114594次,平均每项被引33.78次,H指数和被引频次明显高于其他国家。VOSviewer软件分析结果表明,脓毒症相关文献的关键词主要集中于"疾病相关""发病机制相关""诊治相关""实验研究相关""预后相关"等。结论:2010—2020年脓毒症相关文献发文量以美国、中国和德国最多,其中中国发文量增速最快。近十余年,中国脓毒症相关文献总量位居世界第2位,且中国2020年单年发文量已超过美国跃居全球首位,但文献质量与西方国家文献仍存在较大差距。
