Abundant dinosaur remains have been discovered from the Heilongjiang/Amur area for over one hundred years.Among these discoveries,an isolated small theropod tooth recently found from the lower part of the Yuliangzi Fo...Abundant dinosaur remains have been discovered from the Heilongjiang/Amur area for over one hundred years.Among these discoveries,an isolated small theropod tooth recently found from the lower part of the Yuliangzi Formation of Jiayin displays highly distinctive morphological features.It can be identified as a Troodon-morphotype tooth based on mesiodistal constriction at the base of the crown and large,hook-like denticles extending the entire length of both carinae.Previously,Troodon remains were mainly found in North America.Some isolated Troodon teeth were also discovered in Blagoveschensk and Kundur localities on the left bank of the Heilongjiang river.This specimen represents the first occurrence of Troodon-morphotype tooth in Jiayin,Heilongjiang,Northeast China.The presence of this taxon in Jiayin,Blagoveschensk and Kundur localities in the Heilongjiang area provides new evidence for faunal exchange between North America and Asia through Cretaceous Beringia.展开更多
Fossil lizards are scarce in Jinlin Province,with only two jaws of Middle Eocene Acrodonta.Here the authors report the first scincomorph lizard materials from the early Campanian Nenjiang Formation in Nong’an,Changch...Fossil lizards are scarce in Jinlin Province,with only two jaws of Middle Eocene Acrodonta.Here the authors report the first scincomorph lizard materials from the early Campanian Nenjiang Formation in Nong’an,Changchun,Jilin Province.Three tooth morphologies of scincomorph lizards represented by fragmentary dentaries are tentatively identified as Scincomorpha.The morphology of the crowns indicates probably the insectivorous and omnivorous diets of these small lizards.It is the first lizard fossils discovered in the Late Cretaceous of Northeast China,extends the known paleogeographic distribution of scincomorph lizards,and provides new information about the terrestrial vertebrate fauna of the Cretaceous Songliao Basin.展开更多
The Last Glacial Maximum (LGM, c. 26-16 ka) and the Holocene Optimum (HO, c. 9-5 ka) were characterized by cold-dry and warm-wet climates respectively in the recently geological Earth. How Chinese deserts and sand fie...The Last Glacial Maximum (LGM, c. 26-16 ka) and the Holocene Optimum (HO, c. 9-5 ka) were characterized by cold-dry and warm-wet climates respectively in the recently geological Earth. How Chinese deserts and sand fields responded to these distinctive climatic changes is still not clear, however. To reconstruct environments of the deserts and sand fields during the LGM and HO is helpful to understand the forcing mechanisms of environment change in this arid region, and to test paleoclimatic modeling results. Through our long-term field and laboratory investigations, 400 optically stimulated luminescence (OSL) ages and more than 100 depositional records in the Chinese deserts and sand fields were obtained; on the basis of these data, we reconstruct spatial distributions of the deserts and sand fields during the LGM and HO. Our results show that the sand fields of Mu Us, Hunshandake, Horqin and Hulun Buir in northern and northeastern China had expanded 25%, 37%, 38% and 270%, respectively, during the LGM; the sand fields of Gonghe in the northeastern Qinghai-Tibetan Plateau had expanded 20%, and the deserts of Badain Jaran, Tengger in central northern China had expanded 39% and 29% separately during the LGM; the deserts of Taklimakan, Gurbantünggüt and Kumtag in northwestern China had expanded 10%-20% respectively, compared to their modern areas. On the other hand, all of the sand fields were nearly completely covered by vegetation during the HO; the deserts in northwestern and central northern China were reduced by around 5%-20% in area during this time. Lakes in this arid region were probably expanded during the HO but this conclusion needs more investigation. Compared with the geological distributions of deserts and sand fields, human activity has clearly changed (expanded) the area of active sand dunes at the present time. Our observations show that environmental conditions of Chinese deserts and sand fields are controlled by regional climate together with human activity.展开更多
We present the first quantitative estimation of monsoon precipitation during the late glaciaI-Holocene in the sandy land of northern China, based on organic carbon isotopic composition data from a loess-sand sequence ...We present the first quantitative estimation of monsoon precipitation during the late glaciaI-Holocene in the sandy land of northern China, based on organic carbon isotopic composition data from a loess-sand sequence at margin of the Mu Us sandy land. We use the relationship between monsoon precipitation and the carbon isotopic composition of modern soils as an analogue, with a minor modification, to reconstruct precipitation back to c. 47 ka ago. The preliminary results indicate that annual monsoon precipitation was high after 8 ka, with an average of 435 mm; and it decreased during 18 and 8 ka with a mean value of 194 mm. The precipitation value of 47-18 ka varied between the two. We compare the recon- structed precipitation with other records and paleoclimatic modeling results, showing that our record agrees with reconstructions of the monsoon precipitation from other sources, even capturing short climatic events such as the Younger Dryas. We suggest that solar irradiance, high-latitude temperature/ice volume and local evaporation have together modified moistures in the sandy land.展开更多
TiO2 nanoflakes were prepared by hydrothermal precipitation method using Ti（SO4）2 as titanium source and NaOH solution as alkaline medium. Their surface morphology, grain size measured after high temperature calci- ...TiO2 nanoflakes were prepared by hydrothermal precipitation method using Ti（SO4）2 as titanium source and NaOH solution as alkaline medium. Their surface morphology, grain size measured after high temperature calci- nation and effect on the electrochemical performance of Li ion battery were discussed. TiO2 nanoflakes were charac- terizated by means of transmission electron microscopy（TEM）, X-ray powder diffraction（XRD）, N2 adsorp- tion-desorption isothermal assay, cyclic voltammetry（CV） and cycle performance test. The result of electrochemical performance test shows that the prepared TiO2 nanoflakes have high discharge specific capacity and good cycle per- formance. Discharge specific capacity for the first circle at the discharge rate of 0.1 C is 261.5 mA·h·g-1. After 90 cycles, the discharge capacity reduces to 172.2 mA·h·g-1.展开更多
文摘通过熔融共混制备玄武岩纤维(BF)/尼龙6(PA6)复合材料,研究化学处理BF对复合材料界面结合性能的影响,并对BF与复合材料进行微观表征。结果表明,H_(2)SO_(4)与KOH处理后的纤维表面均发生变化,与PA6基体之间的界面结合强度有所提高,1 mol/L的H_(2)SO_(4)处理的复合材料的力学性能最佳,拉伸强度为102.44 MPa,冲击强度为15.38 k J/m^(2)。
基金Supported by National Nature Science Foundation of China(No.41202012).
文摘Abundant dinosaur remains have been discovered from the Heilongjiang/Amur area for over one hundred years.Among these discoveries,an isolated small theropod tooth recently found from the lower part of the Yuliangzi Formation of Jiayin displays highly distinctive morphological features.It can be identified as a Troodon-morphotype tooth based on mesiodistal constriction at the base of the crown and large,hook-like denticles extending the entire length of both carinae.Previously,Troodon remains were mainly found in North America.Some isolated Troodon teeth were also discovered in Blagoveschensk and Kundur localities on the left bank of the Heilongjiang river.This specimen represents the first occurrence of Troodon-morphotype tooth in Jiayin,Heilongjiang,Northeast China.The presence of this taxon in Jiayin,Blagoveschensk and Kundur localities in the Heilongjiang area provides new evidence for faunal exchange between North America and Asia through Cretaceous Beringia.
文摘Fossil lizards are scarce in Jinlin Province,with only two jaws of Middle Eocene Acrodonta.Here the authors report the first scincomorph lizard materials from the early Campanian Nenjiang Formation in Nong’an,Changchun,Jilin Province.Three tooth morphologies of scincomorph lizards represented by fragmentary dentaries are tentatively identified as Scincomorpha.The morphology of the crowns indicates probably the insectivorous and omnivorous diets of these small lizards.It is the first lizard fossils discovered in the Late Cretaceous of Northeast China,extends the known paleogeographic distribution of scincomorph lizards,and provides new information about the terrestrial vertebrate fauna of the Cretaceous Songliao Basin.
基金supported by the Global Changes Program of Ministry of Science and Technology of China(2010CB950203)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA05120704)+1 种基金the National Natural Science Foundation of China(40930103 and 41021002)China National Science and Technology Basic Work Program(2006FY110800 and 2012FY111700)
文摘The Last Glacial Maximum (LGM, c. 26-16 ka) and the Holocene Optimum (HO, c. 9-5 ka) were characterized by cold-dry and warm-wet climates respectively in the recently geological Earth. How Chinese deserts and sand fields responded to these distinctive climatic changes is still not clear, however. To reconstruct environments of the deserts and sand fields during the LGM and HO is helpful to understand the forcing mechanisms of environment change in this arid region, and to test paleoclimatic modeling results. Through our long-term field and laboratory investigations, 400 optically stimulated luminescence (OSL) ages and more than 100 depositional records in the Chinese deserts and sand fields were obtained; on the basis of these data, we reconstruct spatial distributions of the deserts and sand fields during the LGM and HO. Our results show that the sand fields of Mu Us, Hunshandake, Horqin and Hulun Buir in northern and northeastern China had expanded 25%, 37%, 38% and 270%, respectively, during the LGM; the sand fields of Gonghe in the northeastern Qinghai-Tibetan Plateau had expanded 20%, and the deserts of Badain Jaran, Tengger in central northern China had expanded 39% and 29% separately during the LGM; the deserts of Taklimakan, Gurbantünggüt and Kumtag in northwestern China had expanded 10%-20% respectively, compared to their modern areas. On the other hand, all of the sand fields were nearly completely covered by vegetation during the HO; the deserts in northwestern and central northern China were reduced by around 5%-20% in area during this time. Lakes in this arid region were probably expanded during the HO but this conclusion needs more investigation. Compared with the geological distributions of deserts and sand fields, human activity has clearly changed (expanded) the area of active sand dunes at the present time. Our observations show that environmental conditions of Chinese deserts and sand fields are controlled by regional climate together with human activity.
基金National Natural Science Foundation of China, No.41321062 No.41371203+1 种基金 The Global Changes Program of China, 2010CB950203 The Priority Academic Program Development of Jiangsu Higher Education Institu tions, The Fundamental Research Funds for the Central Universities, No. 1082020904
文摘We present the first quantitative estimation of monsoon precipitation during the late glaciaI-Holocene in the sandy land of northern China, based on organic carbon isotopic composition data from a loess-sand sequence at margin of the Mu Us sandy land. We use the relationship between monsoon precipitation and the carbon isotopic composition of modern soils as an analogue, with a minor modification, to reconstruct precipitation back to c. 47 ka ago. The preliminary results indicate that annual monsoon precipitation was high after 8 ka, with an average of 435 mm; and it decreased during 18 and 8 ka with a mean value of 194 mm. The precipitation value of 47-18 ka varied between the two. We compare the recon- structed precipitation with other records and paleoclimatic modeling results, showing that our record agrees with reconstructions of the monsoon precipitation from other sources, even capturing short climatic events such as the Younger Dryas. We suggest that solar irradiance, high-latitude temperature/ice volume and local evaporation have together modified moistures in the sandy land.
文摘TiO2 nanoflakes were prepared by hydrothermal precipitation method using Ti（SO4）2 as titanium source and NaOH solution as alkaline medium. Their surface morphology, grain size measured after high temperature calci- nation and effect on the electrochemical performance of Li ion battery were discussed. TiO2 nanoflakes were charac- terizated by means of transmission electron microscopy（TEM）, X-ray powder diffraction（XRD）, N2 adsorp- tion-desorption isothermal assay, cyclic voltammetry（CV） and cycle performance test. The result of electrochemical performance test shows that the prepared TiO2 nanoflakes have high discharge specific capacity and good cycle per- formance. Discharge specific capacity for the first circle at the discharge rate of 0.1 C is 261.5 mA·h·g-1. After 90 cycles, the discharge capacity reduces to 172.2 mA·h·g-1.
