Recent advances on study of hadrosaurid dinosaurs in Heilongjiang(Amur) River area between China and Russia          下载免费PDF全文

Pascal Godefroit  Pascaline Lauters  Jimmy Van Itterbeeck  Yuri L. Bolotsky  Ivan Y. Bolotsky 《世界地质(英文版)》2011,(3):160-191

Four main dinosaur-bearing sites have been investigated in latest Cretaceous deposits from the Amur/Heilongjiang Region: Jiayin and Wulaga in China (Yuliangze Formation) ,Blagoveschensk and Kundur in Rus- sia (Udurchukan Formation) . More than 90% of the bones discovered in these localities belong to hollowcrested lambeosaurine hadrosaurids: Charonosaurus jiayinensis at Jiayin,Amurosaurus riabinini at Blagoveschensk, Olorotitan arharensis at Kundur,and Sahaliyania elunchunorum at Wulaga. Flat-headed hadrosaurine hadrosau- rids are much less numerous,but appear well diversified as well: Kerberosaurus manakini at Blagoveschensk, Wulagasaurus dongi at Wulaga,and a new genus at Kundur. Theropods are represented by shed teeth and isolated bones; isolated scutes and teeth discovered at Kundur are tentatively attributed to nodosaurids. Palynologi- cal studies suggest that these sites are probably synchronous with the Lancian’ vertebrate localities of western North America,which represent the youngest dinosaur faunas in this area. However,the latest Cretaceous dinosaur assemblages are completely different in the Amur/Heilongjiang region (lambeosaurines abundant,ceratopsids absent) and in western North America (ceratopsids abundant,lambeosaurines extremely rare or absent) . This probably reflects some kind of geographical barrier between both areas by Maastrichtian time rather than strong differences in palaeoecological conditions.  相似文献   

摄影测量模型重叠区信息匹配     

Doyts.  Y 吴志忠 《四川测绘》1992,15(4):161-165

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用有限元法进行三维电阻率反演     

Sasaki  Y 李惠民 《物探化探译丛》1995,(2):34-42

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日本东北部北上地区磁铁矿系列花岗质侵入体...     

Kuroda  Y 干国梁 《国外花岗岩类地质与矿产》1990,(2):7-12

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Probing the Deepest Limits of the Earth’s Biosphere     

Thomas L. Kieft  T.C. Onstott  Maggie C. Y. Lau  Barbara Sherwood Lollar 《《地质学报》英文版》2018,92(Z1):195-195

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In-depth improvement of soil at the base of roads on taliks     

Alexey Y. Burukin  Svyatoslav Ya. Lutskiy  Konstantin N. Khripkov 《寒旱区科学》2015,7(5):475-481

The article presents a new technological solution to improve the safety of embankment bases on taliks during construction periods. The use of geotextile-sleeved sand columns and geogrids on low-temperature permafrost is investigated. The correlations between mechanical and temperature processes under this in-depth base improvement method are calculated.  相似文献   

A Review on the Taxonomic, Evolutionary and Phytogeographic Studies of the Lotus Plant (Nelumbonaceae: Nelumbo)   总被引：1，自引：0，他引：1  

LI Y  Popova SVETLANA  YAO Jianxin  and LI Chengsen 《《地质学报》英文版》2014,88(4):1252-1261

Nelumbo Adans. （Nelumbonaceae） is an important member of the early-diverging eudicots. It contains two extant species： N. nucifera Gaertn. （the Sacred lotus）, distributed in Asia and Australia and N. lutea Willd. （the American lotus）, occurring in North America. This paper reviews the taxonomic, evolutionary and phytogeographic studies of the genus Nelumbo, and also raises scientific questions about it in further paleobotanic research. There are about 30 fossil species of Nelumbo established since the Early Cretaceous. Based on fossil studies, the ancestors of the extant N. nucifera and N. lutea are respectively considered to be N. protospeciosa from the Eocene to Miocene of Eurasia, and N. protolutea from the Eocene of North American. However, molecular systematic studies indicate that N. nucifera and N. lutea are probably split from a common ancestor during the Late Miocene to Early Pliocene, or even the Pleistocene, rather than separate relicts from extinct species on different continents. The characters of lotus stomatal development, seedling morphology as well as its flowering, pollination and fertilization in air reveal that it evolves from the land plants. Fossil data of Nelumbo indicates that the genus first occurs in mid-latitude area of Laurasia in the Early Cretaceous, then becomes widespread in North America and Eurasia and expands into Africa and South America during the Late Cretaceous; the genus probably colonizes the Indian Subcontinent from Asia during the Early Eocene after the collision of India and the Asian plates; the genus becomes extinct in Europe, but survives in Asia and North America during the Quaternary Ice Age, and later forms the present East Asia and North Australia-North America disjunctive distribution.  相似文献   

Chlorinated organic contaminants in surface sediments from the Yangtze Estuary and nearby coastal areas,China   总被引：12，自引：0，他引：12  

Liu M  Yang Y  Hou L  Xu S  Ou D  Zhang B  Liu Q 《Marine pollution bulletin》2003,46(5):672-676

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基于同步辐射X射线CT的无烟煤样孔隙分布表征          下载免费PDF全文

王润花  王海鹏  李建莉  王晋庥  李琨杰  Y. S. Yang 《CT理论与应用研究》2021,30(6):691-700

本文利用同步辐射X射线对一沁水盆地无烟煤样在24 keV的能量下进行了成像,并重构得到其CT切片。分别采用数字地形模型（DTM）和数据约束模型（DCM）对样品的CT切片进行分析。研究结果表明,对本文所用煤样,DTM计算得到的煤样孔隙率与真密度和视相对密度实验法测得孔隙率较为接近,但利用DTM确定的阈值进行阈值分割提取到的样品孔隙率与DTM计算所得孔隙率之间偏差较大。DCM计算得到的孔隙率与DTM计算得到的孔隙率及实验测试结果均较为接近。DCM模型考虑了样品CT成像过程中的部分体积效应,得到小于CT体元的孔隙分布信息,在一定程度上拓展了CT成像技术的表征尺度。DCM计算结果显示,煤样中孔隙更多与煤基质和矿物组分以部分占据CT体元的形式存在。   相似文献   

Pushover analysis of reinforced concrete frames considering shear failure at beam-column joints     

Y.C.Sung  T.K.Lin  C.C.Hsiao  M.C.Lai 《地震工程与工程振动(英文版)》2013,12(3):373-383

Since most current seismic capacity evaluations of reinforced concrete(RC) frame structures are implemented by either static pushover analysis(PA) or dynamic time history analysis,with diverse settings of the plastic hinges(PHs) on such main structural components as columns,beams and walls,the complex behavior of shear failure at beam-column joints(BCJs) during major earthquakes is commonly neglected.This study proposes new nonlinear PA procedures that consider shear failure at BCJs and seek to assess the actual damage to RC structures.Based on the specifications of FEMA-356,a simplified joint model composed of two nonlinear cross struts placed diagonally over the location of the plastic hinge is established,allowing a sophisticated PA to be performed.To verify the validity of this method,the analytical results for the capacity curves and the failure mechanism derived from three different full-size RC frames are compared with the experimental measurements.By considering shear failure at BCJs,the proposed nonlinear analytical procedures can be used to estimate the structural behavior of RC frames,including seismic capacity and the progressive failure sequence of joints,in a precise and effective manner.  相似文献