Qamdo block in the east Tibet lay in front of southwestern margin of the Yangtze landmass and was one of many micro\|blocks between the Gondwana and the Eurasia continents .It played an important role in the developme...Qamdo block in the east Tibet lay in front of southwestern margin of the Yangtze landmass and was one of many micro\|blocks between the Gondwana and the Eurasia continents .It played an important role in the development of the multi\|arc\|basin system of the north sector of the Jinsha\|lancang\|nujiang rivers . Space\|time texture of the block reflected the tectonic evolution of the east Tibet and neighbouring areas directly, providing important information for evolutionary history of the east Tethys.1\ Crustal structure of the Qamdo block\;Crustal structure of the Qamdo block is characterized by “double basement and double cover”.By double basement is meant the Middle—Upper Proterozoic crystalline basement and the Lower Paleozoic folded basement. The Middle—Upper Proterozoic crystalline basement is composed of medium\|high\|grade metamorphic biotite\|plagiogneiss, plagioclase\|amphibole schist, nacritid intercalated with (intermediate\|) basic metavolcanite. These rocks are characteristic of strong ductile deformed metamorphic core complex. The zircon of gneiss yields an U\|Pb age of 1680～2200Ma while the basic metavolcanite give a Sm\|Nd age of 1594Ma.The Lower Paleozoic folded basement consists of the Lower Ordovician and Silurian. Basement of the Qamdo block is similar to that of the Yangtze landmass. By double cover we mean two covers consisting of the Upper Paleozoic and Mesozoic, respectively. The Upper Paleozoic is composed of carbonate and clastic rock which were formed from epicontinental to back\|arc basins. The Mesozoic consists of the Upper Triassic—Cretaceous concordant formations which were formed in a back\|arc foreland basin.Sequences of the formations are molasse, neritic carbonate, paralic coal\|bearing rock and terrigenous red clastic rock from the bottom to the top.展开更多
China's urban agricultural development takes on stage evolution,and functional structure,customer structure,industrial organization,innovation activity,spatial form and industrial value of each stage has significa...China's urban agricultural development takes on stage evolution,and functional structure,customer structure,industrial organization,innovation activity,spatial form and industrial value of each stage has significant difference. Using the system variable analysis method,this paper established the urban agricultural development system including six types of functional variables. On the basis of summarizing stage characteristics,it analyzed reasons for stage characteristics focusing on four key variables,i. e. cost,efficiency,connection,and risk. Finally,it came up with recommendations for promoting China's urban agricultural development with the aid of stage development rules.展开更多
We study the global star formation law, the relation between the gas and star formation rate （SFR） in a sample of 130 local galaxies with infrared （IR） luminosities spanning over three orders of magnitude （109-10...We study the global star formation law, the relation between the gas and star formation rate （SFR） in a sample of 130 local galaxies with infrared （IR） luminosities spanning over three orders of magnitude （109-1012 Lo）, which includes 91 normal spiral galaxies and 39 （ultra）luminous IR galaxies [（U）LIRGs]. We derive their total （atomic and molecular） gas and dense molecular gas masses using newly available HI, CO and HCN data from the literature. The SFR of galaxies is determined from total IR （8-1000 μm） and 1.4 GHz radio continuum （RC） luminosities. The galaxy disk sizes are defined by the de-convolved elliptical Gaussian FWHM of the RC maps. We derive the galaxy disk-averaged SFRs and various gas surface densities, and investigate their relationships. We find that the galaxy disk-averaged surface density of dense molecular gas mass has the tightest correlation with that of SFR （scatter -0.26 dex）, and is linear in log-log space （power-law slope of N=1.03±0.02） across the full galaxy sample. The correlation between the total gas and SFR surface densities for the full sample has a somewhat larger scatter （-0.48 dex）, and is best fit by a power-law with slope 1.45±0.02. However, the slope changes from -1 when only normal spirals are considered, to -1.5 when more and more （U）LIRGs are included in the fitting. When different CO-to-H2 conversion factors are used to infer molecular gas masses for normal galaxies and （U）LIRGs, the bi-modal relations claimed recently in CO observations of high-redshift galaxies appear to also exist in local populations of star-forming galaxies.展开更多
文摘Qamdo block in the east Tibet lay in front of southwestern margin of the Yangtze landmass and was one of many micro\|blocks between the Gondwana and the Eurasia continents .It played an important role in the development of the multi\|arc\|basin system of the north sector of the Jinsha\|lancang\|nujiang rivers . Space\|time texture of the block reflected the tectonic evolution of the east Tibet and neighbouring areas directly, providing important information for evolutionary history of the east Tethys.1\ Crustal structure of the Qamdo block\;Crustal structure of the Qamdo block is characterized by “double basement and double cover”.By double basement is meant the Middle—Upper Proterozoic crystalline basement and the Lower Paleozoic folded basement. The Middle—Upper Proterozoic crystalline basement is composed of medium\|high\|grade metamorphic biotite\|plagiogneiss, plagioclase\|amphibole schist, nacritid intercalated with (intermediate\|) basic metavolcanite. These rocks are characteristic of strong ductile deformed metamorphic core complex. The zircon of gneiss yields an U\|Pb age of 1680～2200Ma while the basic metavolcanite give a Sm\|Nd age of 1594Ma.The Lower Paleozoic folded basement consists of the Lower Ordovician and Silurian. Basement of the Qamdo block is similar to that of the Yangtze landmass. By double cover we mean two covers consisting of the Upper Paleozoic and Mesozoic, respectively. The Upper Paleozoic is composed of carbonate and clastic rock which were formed from epicontinental to back\|arc basins. The Mesozoic consists of the Upper Triassic—Cretaceous concordant formations which were formed in a back\|arc foreland basin.Sequences of the formations are molasse, neritic carbonate, paralic coal\|bearing rock and terrigenous red clastic rock from the bottom to the top.
基金Supported by Philosophy and Social Science Planning Project of Beijing(12JGC105)Key Project of National Soft Science Research Plan(2013GXS4D097)Self-supporting Project of Beijing Institute of Scienceand technology Information
文摘China's urban agricultural development takes on stage evolution,and functional structure,customer structure,industrial organization,innovation activity,spatial form and industrial value of each stage has significant difference. Using the system variable analysis method,this paper established the urban agricultural development system including six types of functional variables. On the basis of summarizing stage characteristics,it analyzed reasons for stage characteristics focusing on four key variables,i. e. cost,efficiency,connection,and risk. Finally,it came up with recommendations for promoting China's urban agricultural development with the aid of stage development rules.
基金supported by the National Natural Science Foundation of China (Grant Nos.10833006 and 10621303)the National Basic Research Program of China (Grant No.2007CB815406)
文摘We study the global star formation law, the relation between the gas and star formation rate （SFR） in a sample of 130 local galaxies with infrared （IR） luminosities spanning over three orders of magnitude （109-1012 Lo）, which includes 91 normal spiral galaxies and 39 （ultra）luminous IR galaxies [（U）LIRGs]. We derive their total （atomic and molecular） gas and dense molecular gas masses using newly available HI, CO and HCN data from the literature. The SFR of galaxies is determined from total IR （8-1000 μm） and 1.4 GHz radio continuum （RC） luminosities. The galaxy disk sizes are defined by the de-convolved elliptical Gaussian FWHM of the RC maps. We derive the galaxy disk-averaged SFRs and various gas surface densities, and investigate their relationships. We find that the galaxy disk-averaged surface density of dense molecular gas mass has the tightest correlation with that of SFR （scatter -0.26 dex）, and is linear in log-log space （power-law slope of N=1.03±0.02） across the full galaxy sample. The correlation between the total gas and SFR surface densities for the full sample has a somewhat larger scatter （-0.48 dex）, and is best fit by a power-law with slope 1.45±0.02. However, the slope changes from -1 when only normal spirals are considered, to -1.5 when more and more （U）LIRGs are included in the fitting. When different CO-to-H2 conversion factors are used to infer molecular gas masses for normal galaxies and （U）LIRGs, the bi-modal relations claimed recently in CO observations of high-redshift galaxies appear to also exist in local populations of star-forming galaxies.
