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821.
HULina&BIANXiufang 《科学通报(英文版)》2004,49(1):1-9
“Liquid fragility“ is a concept that has been widely used in the investigation on the glass community,though it was presented less than two decades ago. The concept enables the comparison between the glass-forming liquids with different dynamic characters by using a general criterion, in which the temperature scale is reduced by the glass transition temperature. In order to illuminate the significance of the concept in the fields of the glass transition,structural relaxation process and the structure of supercooled liquids, the accomplished progress and the faced challenges are summarized from different aspects such as on the correlation between dynamics and thermodynamic characters of condensed matters, on the energy landscape, on the nonexponential relaxation and on the theoretical model of microstructure and medium-range order. The tendency of investigation in “liquid fragility“ is also evaluated. 相似文献
822.
First SHRIMP zircon U-Pb ages for Hutuo Group in Wutaishan: Further evidence for Palaeoproterozoic amalgamation of North China Craton 总被引:10,自引:0,他引:10
S. A. Wilde ZHAO Guochun WANG Kaiyi & SUN MinDepartment of Applied Geology Curtin University of Technology PO Box U Perth Australia Department of Earth Science University of Hong Kong Pokfulam Road Hong Kong China Institute of Geology Geophysics Chinese Academy of Sciences Beijing ChinaCorrespondence should be addressed to S. A. Wilde 《科学通报(英文版)》2004,49(1):83-90
A felsic tuffaceous rock, obtained from a metamorphosed sequence of volcanics and sediments of the Hutuo Group, 8 km south of Taihuai in Wutaishan, contains two zircon populations. These record SHRIMP 207Pb/206Pb weighted mean ages of 2180±5 Ma and 2087±9 Ma, respectively. The older date is within error of the age of the Dawaliang Granite in Wutaishan and is considered to be 相似文献
823.
YANGJuxiang FANGYu BAIChaoliang HUDaodao ZHANGYing 《科学通报(英文版)》2004,49(19):2026-2032
N-isopropylacrylamide (NIPAM) and acrylic acid (AA) copolymer microspheres with various compositions were prepared by reverse suspension polymerization technique. The microspheres thus prepared were employed as micro-reactors for the deposition of CuS. In this way, several CuS-P(NIPAM-co-AA) composite microspheres with different surface morphologies were prepared. It was demonstrated that the surface structures of the composite microspheres can be tailored to a certain extent by varying the ratio of the two monomer units in the template (microgels) and/or the amount of CuS deposited. It is in prospect that the inherent advantages of microgel templates (the size, composition, charge nature and density, and crosslinking density could be easily controlled) would make the microgel template method extremely useful in the preparation of composite microspheres with different patterned surface structures. 相似文献
824.
SUHui LUJunxia WANGYunhua RENYi XIEYi HUANGZhongxian 《科学通报(英文版)》2004,49(18):1914-1919
Phenylalanine-58 is one of the conservative residues in the hydrophobic pocket of Cyt bs, which forms aromatic stacking with the heme b. Previous study showed that both the stacking and the property of the aromatic residue affect hydrophobicity of the heme pocket, leading to change of protein‘s property. In order to further reveal the essence we esterify the heme propionate of Cyt bs, F58Y and F58W, and eliminate the hydrogen bond between heme propionate and Ser64 in examining the effect of hydrogen net on the π-π interaction. In this paper thermal denaturation of DME-Cyt b5 and its F58Y and F58W mutants has been studied by UV-visible and CD spectra. The heme transfer reactions between these proteins and apo-myoglobin have been studied as well. The results demonstrate that esterification did not destroy the aromatic stacking; however, it affects the stability of the proteins due to different volumes, hydropho-bicities and hydrogen bonds forming ability of these substituents. 相似文献
825.
Continuum models for freeways with two lanes and numerical tests 总被引:4,自引:0,他引:4
TANGTieqiao HUANGHaijun 《科学通报(英文版)》2004,49(19):2097-2104
This paper deals with the continuum modeling of traffic dynamics for freeways with two lanes where the faster vehicles are allowed to travel on both lanes while the slower vehicles are allowed to travel on one lane only. The speed gradient-based momentum equation is used to develop the traffic models for each lane. Using the proposed models,some nonequilibrium phenomena such as small disturbance instability and stop-and-go waves, together with results from numerical tests are investigated. The conditions for keeping the models‘ linear stability are presented. 相似文献
826.
U-Pb ages of Kude and Sajia leucogranites in Sajia dome from North Himalaya and their geological implications 总被引:13,自引:0,他引:13
ZHANG Hongfei Nigel Harris Randy Parrish ZHANG Li & ZHAO Zidan .Faculty of Earth Sciences China University of Geosciences Wuhan China .Department of Earth Sciences The Open University Milton Keynes MK AA UK .NERC Isotope Geosciences Laboratory British Geological Survery Nottingham NG GG UK .School of Earth Science Land Resources China University of Geosciences Beijing China 《科学通报(英文版)》2004,49(19):2087-2092
~~U-Pb ages of Kude and Sajia leucogranites in Sajia dome from North Himalaya and their geological implications~~ FallMeetingSuppl.Abstr.,2001,0830h.
10.Lee,J.,Hacker,B.R.,Dinklage,W.S. et al.,Evolution of theKangmarDome, southernTibet:Structural, petrologic, and ther- mochronologic constraints,Tectonics,2000,19:872—895.
11.Parrish,R.R.,Roddick,J.C.,Loveridge,W.D. et al.,Ura- nium-lead analytical techniques at the geochronology laboratory,GeologicalSurvey ofCanada,Geol.Sur… 相似文献
827.
XUWenzhong WANGXin FENGQi ZHANGLei LIUYaoguang HANBin CHONGKang XUZhihong TANKehui 《科学通报(英文版)》2004,49(4):355-362
Previously, we isolated a vernalization-related gene, VER2, from winter wheat (Triticum aestivum L.) and its expression was restricted in the immature leaves of vernalized wheat seedlings. To further investigate the regulation of VER2 expression and the function of its promoter, we isolated a 41.7 kb genomic clone containing VER2 gene from atransformation-competent artificial chromosome (TAC) library of wheat (Triticum aestivum-Haynaldia villosa). The sequence analysis showed that there were eleven predicted genes in the TAC. The exons of gene 3 corresponded to the cDNA sequence of VER2 gene. Analysis of VER2 promoter structure showed that there were three small repeat sequences divided by two large repeat sequences. The putative response elements, such as abscisic acid response elements (ABRE), MeJA-response elements (Me-JARE), low-temperature response elements (LTR), endosperm expression elements, MYB binding sites and similar elements to GA response elements (GARE), were involved in the VER2 promoter region. Construct containing the VER2 promoter (-5895 to 73) driving GFP reporter gene was bombarded into vernalized or non-verualized immature leaves in wheat. The vernalized immature leaves showed bright green fluorescence after incubation for 24 h, however, the green fluorescence was not observed in the non-vernalization leaves under the same condition. These results suggested that vernalization was essential for the function of VER2 promoter in the immature leaves of winter wheat. 相似文献
828.
Issues and prospects of belowground ecology with special reference to global climate change 总被引:9,自引:0,他引:9
HEJinsheng WANGZhengquan FANGJingyun 《科学通报(英文版)》2004,49(18):1891-1899
The theory of ecology is based on over 100 a of research and investigation, all centered on aboveground patterns and processes. However, as contemporary ecologists are increasingly acknowledging, belowground structures, functions, and processes are some of the most poorly understood areas in ecology. This lack of understanding of belowground ecological processes seriously restricts the advance of global change research. The interdisciplinary field of belowground ecology began to flourish in the 1990s, along with the expansion of global change research, and quickly gained momentum. Belowground ecology aims to investigate belowground structures, functions, and processes, as well as their relationships with corresponding aboveground features, emphasizing the responses of belowground systems under global change conditions. Key research areas include root ecology, belowground animals, and soil microorganisms. This review summarizes and analyzes the relationships between aboveand belowground ecosystems, root ecology, root biogeography, belowground biodiversity, as well as research areas with particular challenges and progress. This commentary emphasizes certain theoretical issues concerning the responses of belowground processes to global change, and concludes that belowground ecology is a critical research priority in the 21st century. 相似文献
829.
LUOKunli ZHANGXinmin CHENChanghe LUYilun 《科学通报(英文版)》2004,49(20):2183-2189
Arsenicisoneofthemostpopularandharmele-mentsintheenvironment[13].ThearsenicpollutionintheatmosphereisveryheavyinFushun,Shenyang,Lanzhou,Guiyang,ChengduandChongqing,etc.IntheSouthwestChinathereare3000eventsofarsenictoxicosisbecauseofhigharseniccoalscombustionandabout10000peopleareeffected[4,5].Therefore,thesourcesofarsenicintheenvironmentanditstreatmentarepaidmoreattentionto.CoalisthebasicpowersourceinChinaandabout1000milliontonsperyearisconsumeddirectlyasfuel[6,7].Steamcoalburntinpowerstat… 相似文献
830.
Lu Jia |hua Wang Yan . Wuhan University Journals Press Wuhan Hubei China . School of Computer Wuhan University Wuhan Hubei China . School of Mathematics Statistics Wuhan University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2003,8(3):775-778
0 IntroductionHTisimportanttothedevelopmentofanycountryallovertheworld .InChina ,HTbasedonuniversitiesandre searchinstitutesisdevelopingrapidly .DuringtheprocessofR&DofHT ,howdotheresearchersmakedecisionsinconcretecases?Responsibleinstitutionmustdecidehowtomacro controlthein dustry .Thesealldependontheprize,theprobabilityofsuccess,investmentcostofR&Dandthenumberoffirmengagingintheproject.ThetimeofsuccessofR&Dplaysacrucialroleinthemarketplacebecauseafirmthatisthefirsttodiscoveranewtech n… 相似文献