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Search Results: 1 - 10 of 104186 matches for " QuanChao Zhang "
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The size variation and related implications of mandibles in northern China in the past 7000 years
HaiJun Li,QuanChao Zhang,Hong Zhu
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-011-4808-1
Abstract: To better understand variation of Holocene Chinese mandiblular morphology, a study was conducted on 23 metric traits of Neolithic (n=54), Bronze-Iron Ages (n=184) and modern (n=92) adult male mandibles from northern China. Results indicate that the linear characters of these Chinese mandibles evolved in the past 7000 years. From the Neolithic to Bronze-Iron Ages to present day, the overall size of mandibles decreased. The linear characters of the mandiblular features varied between different time periods. The decrease of thickness and height of the mandibular corpus primarily occurred during the Neolithic to Bronze-Iron Ages. The decrease in main size was during the Bronze-Iron Ages to present day. It is possible that mandibles became thinner before the overall size decreased. Comparisons also indicate that the bottom part of the face may have decreased more greatly in breadth than the upper portion. The decrease in mandible size may be associated with changes in climate and diet, and with changes in the craniums size.
Craniofacial morphological microevolution of Holocene populations in northern China
WU XiuJie LIU Wu ZHANG QuanChao,ZHU Hong J NORTON Christopher,
WU
,XiuJie,LIU,Wu,ZHANG,QuanChao,ZHU,Hong,Christopher,J.,NORTON

科学通报(英文版) , 2007,
Abstract: In order to better understand microevolutionary processes in Holocene Chinese craniofacial mor- phology, an analysis has been done on 21 metric traits on Neolithic (n=161), Bronze Age (n=423) and modern (n=134) adult male skulls from northern China. The results indicate that the physical characters of these Chinese populations evolved throughout the Holocene. From the Neolithic to Bronze Age to present day, general trends include: cranial and facial sizes decrease; the nose gets narrower and longer; the orbits become narrower and higher; the head is more globular. The expression of the cranial features varies between the different time periods. The decrease in cranial size primarily occurred from the Bronze Age to present day. However, the decrease in facial size, the narrowing of the nose, and the elevation of the orbits took place throughout the Holocene. These traits are likely still evolving. This evolving pattern of the cranial features for the Holocene Chinese populations is similar to that found elsewhere in the world. The decrease in overall craniofacial size is associated with changes in climate and diet. In addition, it is possible that the craniofacial morphological microevolution is controlled by human evolutionary mechanisms.
Analysis of the matrilineal genetic structure of population in the early Iron Age from Tarim Basin, Xinjiang, China
YinQiu Cui,ShiZhu Gao,ChengZhi Xie,QuanChao Zhang,HaiJing Wang,Hong Zhu,Hui Zhou
Chinese Science Bulletin , 2009, DOI: 10.1007/s11434-009-0647-8
Abstract: Ancient mtDNA data of human remains were analyzed from four early Iron Age Tarim Basin sites (Yuansha, Zaghunluq, Sampula and Niya) in the southern Silk Road region. Haplogroup distributions show that ancient Tarim Basin population was comprised of well-differentiated Western and Eastern matrilineal lineages. Some West lineage of Tarim Basin population originated from Near East and Iran region. Of the East lineages, North and Northeast Asia originated lineages were the main components, and a few Southeast Asian lineages also existed, which indicated a more extensive origin and a more complex admixture. The genetic structure of ancient Tarim Basin population is relatively close to the modern populations of Xinjiang, which implied that the early Iron Age is an important period during the formation of the modern Xinjiang population.
Craniofacial morphological microevolution of Holocene populations in northern China
XiuJie Wu,Wu Liu,QuanChao Zhang,Hong Zhu,Christopher J. Norton
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0227-8
Abstract: In order to better understand microevolutionary processes in Holocene Chinese craniofacial mor-phology, an analysis has been done on 21 metric traits on Neolithic (n=161), Bronze Age (n=423) and modern (n=134) adult male skulls from northern China. The results indicate that the physical characters of these Chinese populations evolved throughout the Holocene. From the Neolithic to Bronze Age to present day, general trends include: cranial and facial sizes decrease; the nose gets narrower and longer; the orbits become narrower and higher; the head is more globular. The expression of the cranial features varies between the different time periods. The decrease in cranial size primarily occurred from the Bronze Age to present day. However, the decrease in facial size, the narrowing of the nose, and the elevation of the orbits took place throughout the Holocene. These traits are likely still evolving. This evolving pattern of the cranial features for the Holocene Chinese populations is similar to that found elsewhere in the world. The decrease in overall craniofacial size is associated with changes in climate and diet. In addition, it is possible that the craniofacial morphological microevolution is controlled by human evolutionary mechanisms.
Evidence that a West-East admixed population lived in the Tarim Basin as early as the early Bronze Age
Chunxiang Li, Hongjie Li, Yinqiu Cui, Chengzhi Xie, Dawei Cai, Wenying Li, Victor H Mair, Zhi Xu, Quanchao Zhang, Idelisi Abuduresule, Li Jin, Hong Zhu, Hui Zhou
BMC Biology , 2010, DOI: 10.1186/1741-7007-8-15
Abstract: Mitochondrial DNA analysis showed that the Xiaohe people carried both the East Eurasian haplogroup (C) and the West Eurasian haplogroups (H and K), whereas Y chromosomal DNA analysis revealed only the West Eurasian haplogroup R1a1a in the male individuals.Our results demonstrated that the Xiaohe people were an admixture from populations originating from both the West and the East, implying that the Tarim Basin had been occupied by an admixed population since the early Bronze Age. To our knowledge, this is the earliest genetic evidence of an admixed population settled in the Tarim Basin.The Tarim Basin in western China, positioned at a critical site on the ancient Silk Road, has played a significant role in the history of human migration, cultural developments and communications between the East and the West. It became famous due to the discovery of many well-preserved mummies within the area. These mummies, especially the prehistoric Bronze Age 'Caucasoid' mummies, such as the 'Beauty of Loulan', have attracted extensive interest among scientists regarding who were these people and where did they come from.Based on analyses of human remains and other archaeological materials from the ancient cemeteries (dated from approximately the Bronze Age to the Iron Age), there is now widespread acceptance that the first residents of the Tarim Basin came from the West. This was followed, in stages, by the arrival of Eastern people following the Han Dynasty [1,2]. However, the exact time when the admixture of the East and the West occurred in this area is still obscure [3]. In 2000, the Xinjiang Archaeological Institute rediscovered a very important Bronze Age site, the Xiaohe cemetery, by utilizing a device employing the global positioning system. The rediscovery of this cemetery provided an invaluable opportunity to further investigate the migrations of ancient populations in the region.The Xiaohe cemetery (40°20'11"N, 88°40'20.3"E) is located in the Taklamakan Desert of north
Two-and three-electrode impedance spectroscopic studies of graphite electrode in the first lithiation
QuanChao Zhuang,LeiLei Tian,GuoZhen Wei,QuanFeng Dong,ShiGang Sun
Chinese Science Bulletin , 2009, DOI: 10.1007/s11434-009-0356-3
Abstract: The first lithiation of graphite electrode was investigated by electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM) in a two-electrode button cell and a three-electrode glass cell. The results demonstrate that the study of the variation of EIS feature of the graphite electrode in the two-electrode button cell with electrode polarization potential decreasing in the first lithiation cannot be used to investigate the formation mechanism of the solid electrolyte interphase (SEI) film. However, the formation and growth process of the SEI film can be acquired by investigating the variation of EIS features of the graphite electrode in the three-electrode glass cell with the decrease of electrode polarization potential in the first lithiation. Moreover, the results also point out that the SEI film on graphite electrode is mainly formed between 1.0 and 0.6 V in the first lithiation.
Studies of the first lithiation of graphite materials by electrochemical impedance spectroscopy
Quanchao Zhuang,Zuofeng Chen,Quanfeng Dong,Yanxia Jiang,Ling Huang,Shigang Sun,
ZHUANG
,Quanchao,CHEN,Zuofeng,DONG,Quanfeng,JIANG,Yanxia,HUANG,Ling,SUN,Shigang

科学通报(英文版) , 2006,
Abstract: First lithiation of graphite electrode in 1 mol/L LiPF6-EC:DEC:DMC electrolyte was investi- gated by electrochemical impedance spectroscopy (EIS). The results illustrated that the first arc in the high-frequency range observed in the Nyquist dia- gram appears near 0.9 V in the initial lithiation of graphite electrode, and its diameter increases with the decrease of polarization potential. These EIS features were attributed to the formation and growth of SEI film. Appropriate equivalent circuit was pro- posed to fit the experimental EIS data. The fitting results revealed the process of the formation and growth of SEI film, and evaluated quantitatively the resistance of charge transfer, as well as the capaci- tance of double layer along with the increase of po- larization potentials.
Mechanism of intercalation and deintercalation of lithium ions in graphene nanosheets
LeiLei Tian,QuanChao Zhuang,Jia Li,YueLi Shi,JianPeng Chen,Feng Lu,ShiGang Sun
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4609-6
Abstract: Graphene nanosheets (GNSs) were synthesized by reducing exfoliated graphite oxides. Their structure, surface morphology and lithium storage mechanism were characterized and investigated systematically using X-ray diffraction, atomic force microscopy, scanning electron microscopy, charge-discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. It was found that the GNSs, which were obtained via chemical synthesis, were primarily less than 10 graphene layers. The GNS electrodes, which were fabricated from the reduced GNSs, exhibited an enhanced reversible lithium storage capacity and good cyclic stability when serving as anodes in lithium-ion batteries. Also, the first-cycle irreversible capacities of the system were relatively high, because of the formation of a solid electrolyte interphase film on the surface of the GNS electrode and the spontaneous stacking of GNSs during the first lithiation. The electrochemical impedance spectroscopy results suggest that the solid electrolyte interphase film on the GNS electrode during first lithiation were primarily formed at potentials between 0.95 and 0.7 V. Also, the symmetry factor of the charge transfer was measured to be 0.446.
An electrochemical impedance spectroscopic study of the electronic and ionic transport properties of LiCoO2 cathode
QuanChao Zhuang,JinMei Xu,XiaoYong Fan,QuanFeng Dong,YanXia Jiang,Ling Huang,ShiGang Sun
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0169-1
Abstract: The storage behavior and process of the first delithiation-lithiation of LiCoO2 cathode were investigated by electrochemical impedance spectroscopy (EIS). The electronic and ionic transport properties of LiCoO2 cathode along with variation of electrode potential were obtained in 1 mol·L 1 LiPF6-EC:DMC: DEC electrolyte solution. It was found that after 9 h storage of the LiCoO2 cathode in electrolyte solutions, a new arc appears in the medium frequency range in Nyquist plots of EIS, which increases with increasing the storage time. In the charge/discharge processes, the diameter of the new arc is reversibly changed with electrode potential. Such variation coincides well with the electrode potential dependence of electronic conductivity of the LiCoO2. Thus this new EIS feature is attributed to the change of electronic conductivity of Li x CoO2 during storage of the LiCoO2 cathode in electrolyte solutions, as well as in processes of intercalation-deintercalationtion of lithium ions. It has been revealed that the reversible increase and decrease of the resistance of SEI film in charge-discharge processes can be also ascribed to the variation of electronic conductance of active materials of the LiCoO2 cathode
Preparation and characterization of a novel composite microporous polymer electrolyte for Li-ion batteries
Zuofeng Chen,Yanxia Jiang,Quanchao Zhuang,Quanfeng Dong,Ye Wang,Shigang Sun
Chinese Science Bulletin , 2005, DOI: 10.1360/982004-394
Abstract: A novel composite microporous polymer electrolyte composed of poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) and mesoporous SBA-15 was prepared. The composite solid polymer electrolyte (CSPE) exhibits ionic conductivity as high as 0.30 mS·cm 1 with a composition of SBA-15 : PVdF-HFP=3 : 8 at room temperature. Infrared transmission spectroscopic results suggested that the mechanism of micropore formation is similar to that of the phase inversion. X-ray diffraction (XRD) results demonstrated that the addition of SBA-15 inhibits the crystallization of PVdF-HFP, while the SBA-15 preserves well its ordered mesoporous structure during the course of preparation. The Li/CSPE/MCF of half-cell was assembled, and it showed a good electrochemical and cyclability performance during charge-discharge cycles.
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