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Search Results: 1 - 10 of 127278 matches for " Li Shuguang "
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Efficient Pr-Skyline Query Processing and Optimization in Wireless Sensor Networks  [PDF]
Jianzhong Li, Shuguang Xiong
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.211101
Abstract: As one of the commonly used queries in modern databases, skyline query has received extensive attention from database research community. The uncertainty of the data in wireless sensor networks makes the corresponding skyline uncertain and not unique. This paper investigates the Pr-Skyline problem, i.e., how to compute the skyline with the highest existence probability in a computational and energy-efficient way. We formulate the problem and prove that it is NP-Complete and cannot be approximated in a given expression. However, the proposed algorithm SKY-SEARCH with pruning techniques can guarantee the computational efficiency given relatively large input size, while the filter-based distributed optimization strategy significantly reduces the transmission cost and the required storage space of the sensor nodes. Extensive experiments verify the efficiency and scalability of SKY-SEARCH and the distributed optimizing strategy.
Decoupling of surface and subsurface sutures in the Dabie orogen and a continent-collisional lithospheric-wedging model: Sr-Nd-Pb isotopic evidences of Mesozoic igneous rocks in eastern China
Shuguang Li,Wei Yang
Chinese Science Bulletin , 2003, DOI: 10.1007/BF03187062
Abstract: There are significant differences of Nd and Pb isotopic compositions between Mesozoic mafic igneous rocks from the North China Block (NCB) and the South China Block (SCB). Mesozoic mantle-derived igneous rocks from the North China Block have very low Nd values ( 15 to 21), and206Pb/204Pb ratios (< 17.9), while those in the SCB are characterized by Nd > 10 and206Pb/204Pb > 18.3. The very low Nd values ( 16 to 20) and206Pb/204Pb ratios (< 17.3) of the early Cretaceous mafic-ultramafic intrusions developed in the north part of the Dabie orogen (NDZ) suggest that the deep lithosphere underneath the NDZ belongs to the NCB but not the SCB. Therefore, although the surface suture between the NCB and SCB is located on the north side of the NDZ, the subsurface suture between the NCB and SCB should be located to the south side of the NDZ. This is consistent with the previous suggestion that the subsurface suture in the Sulu terrane east of the Tanlu fault was the south displacement, but contradictory to northward continental subduction of the SCB. A. continent-collisional lithospheric-wedging model can interpret the decoupling of the surface and subsurface sutures in the Dabie-Sulu orogen. After slab break-off, the continuing convergence of two continental blocks must increase the compression force acting on the suture zone, which might induce the lithosphere splitting of SCB. Thus, the lower crust and lithospheric mantle on the south margin of the NCB can wedge into the north margin of the lithosphere of the SCB along the Dabie-Sulu collision zone. This process caused the overthrust of the mid-upper continental crust with exhumed ultrahigh pressure meta-morphic (UHPM) rocks and underthrust of the deep litho-sphere of the SCB. It could be an important mechanism responsible for the second rapid cooling and uplifting of the UHPM rocks and lithospheric delamination as well as the corresponding magmatism in Jurassic in the Dabie orogen. The southward movement of subsurface suture in the Dabie-Sulu orogen may also provide a tectonic setting in depth for the large-scale Mesozoic magmatic-metallogenesis along the middle-lower reaches of the Yangtse River in eastern China.
Rb-Sr chronology and cooling history of the Renjiawan pyroxenite intrusion in North Dabie Terrane
Yonghong Nie,Shuguang Li
Chinese Science Bulletin , 1999, DOI: 10.1007/BF02896294
Abstract: A group of Rb-Sr ages, i.e. plagioclase-whole rock (WR) isochron age of (205 ±7) Ma, hornblende-WR isochron age of (164 ±10) Ma and biotite-WR isochron age of (123.4 ±1.2) Ma, for one pyroxenite sample from Renjiawan in North Dabie Terrane (NDT) are reported. According to the closure temperature of 600°C for plageoclase and 300°C for biotite, the Renjiawan pyroxenite should intrude into the NDT before 205 Ma, and the younger Rb-Sr ages may reflect the cooling history of the intrusion or reset by the very strong Cretaceous thermal event in NDT.
Sm-Nd age of syncollisional mafic-ultramafic intrusions in the Dabie Mountains
Yonghong Nie,Shuguang Li
Chinese Science Bulletin , 1998, DOI: 10.1007/BF02883934
Abstract: A Sm-Nd age of (228±42) Ma with initial εNd= 16.4 for the Renjiawan pyroxenite intrusion in the North Dabie terrane is reported. This age with another Sm-Nd age of (230 ±44) Ma for the Zhujiapu pyroxenite in the same terrane documents that the pyroxenite in the North Dabie terrane are formed during continental subduction time of the Yangtze craton in the Triassic.
Detachment within subducted continental crust and multi-slice successive exhumation of ultrahigh-pressure metamorphic rocks: Evidence from the Dabie-Sulu orogenic belt
YiCan Liu,ShuGuang Li
Chinese Science Bulletin , 2008, DOI: 10.1007/s11434-008-0387-1
Abstract: Although tectonic models were presented for exhumation of ultrahigh-pressure (UHP) metamorphic rocks during the continental collision, there is increasing evidence for the decoupling between crustal slices at various depths within deeply subducted continental crust. This lends support to the multi-slice successive exhumation model of the UHP metamorphic rocks in the Dabie-Sulu orogen. The available evidence is summarized as follows: (1) the low-grade metamorphic slices, which have geotectonic affinity to the South China Block and part of them records the Triassic metamorphism, occur in the northern margin of the Dabie-Sulu UHP metamorphic zone, suggesting decoupling of the upper crust from the underlying basement during the initial stages of continental subduction; (2) the Dabie and Sulu HP to UHP metamorphic zones comprise several HP to UHP slices, which have an increased trend of metamorphic grade from south to north but a decreased trend of peak metamorphic ages correspondingly; and (3) the Chinese Continental Science Drilling (CCSD) project at Donghai in the Sulu orogen reveals that the UHP metamorphic zone is composed of several stacked slices, which display distinctive high and low radiogenic Pb from upper to lower parts in the profile, suggesting that these UHP crustal slices were derived from the subducted upper and middle crusts, respectively. Detachment surfaces within the deeply subducted crust may occur either along an ancient fault as a channel of fluid flow, which resulted in weakening of mechanic strength of the rocks adjacent to the fault due to fluid-rock interaction, or along the low-viscosity zones which resulted from variations of geotherms and lithospheric compositions at different depths. The multi-slice successive exhumation model is different from the traditional exhumation model of the UHP metamorphic rocks in that the latter assumes the detachment of the entire subducted continental crust from the underlying mantle lithosphere and its subsequent exhumation as a whole. This also reveals the difference between the continental subduction and oceanic subduction. In addition, several important proposals concerning the multi-slice successive exhumation model are made for further studies.
Petrochemical characteristics of leucogranite and a case study of Bengbu leucogranites
SuShu Guo,ShuGuang Li
Chinese Science Bulletin , 2009, DOI: 10.1007/s11434-009-0355-4
Abstract: Leucogranites have a relatively narrow variation in SiO2 content (70.5%–75.5%). Giving similar SiO2 content, leucogranites have relatively higher Al2O3 (>13.5%) and lower TFeO + MgO (<2.5%) contents than those of normal granites. These petrochemical characteristics suggest that leucogranites are derived from partial melting at relatively low temperature and are not significantly affected by fractional crystallization. In the present study, we propose that the Al2O3 vs SiO2 and TFeO + MgO vs SiO2 diagrams can be used to distinguish leucogranites from normal granites. In addition, we report the major element compositions of the Jurassic granitic intrusions from Jingshan-Tushan-Mayishan in the Bengbu area, east-central China. Using the Al2O3 vs SiO2 and TFeO + MgO vs SiO2 diagrams and the comparison with the High Himalayan leucogranites in mineralogical and petrochemical characteristics, we suggest that the Jingshan-Tushan-Mayishan intrusions belong to a leucogranite belt. Similar to those of the High Himalayan leucogranites, the Bengbu leucogranites have low Mg# values, indicating that they resulted from low temperature dehydration partial melting of the subducted continental crust of the South China Block at the crustal depth.
Ba-Nb-Th-La DIAGRAMS USED TO IDENTIFY TECTONIC ENVIRONMENTS OF OPHIOLITE
蛇绿岩生成构造环境的Ba-Th-Nb-La判别图

Li Shuguang,
李曙光

岩石学报 , 1993,
Abstract: Ti-Zr-Y diagrams proposed by J. A. Pearce have widely been used to identify tectonic settings of ophiolite. However, because of considerable overlap in fields for island arc versus mid-oceanic environments and sensibility of Ti to fractional crystallization in basaltic magma, misidentification of tectonic setting is common using these geochemical diagrams. In this paper, the author proposes a group of new geochemical tecotnic discriminant using 4 very incompatible elements (Ba, Nb, Th, La) with similar partition coefficients. Island arc basalts, Mid-ocean ridge basalts and oceanic island basalts can be separated well by Ba/Nb-Ba, Nb/Th-Nb, La/Nb-La and Ba/Nb-Th/Nb diagrams. Back arc basin basalts distribute in both MORB and IAB fields of these diagrams. These diagrams are also successful to identify tectonic settings of ophiolite which include lava and isotropic babbro, because of inmobility of Nb, La, Th, Ba in sea water alteration and insensibility of their ratios to magma process.
Petrochemical characteristics of leucogranite and a case study of Bengbu leucogranites

SuShu Guo,ShuGuang Li,

科学通报(英文版) , 2009,
Abstract: Leucogranites have a relatively narrow variation in SiO2 content (70.5%–75.5%). Giving similar SiO2 content, leucogranites have relatively higher Al2O3 (>13.5%) and lower TFeO + MgO (<2.5%) contents than those of normal granites. These petrochemical characteristics suggest that leucogranites are derived from partial melting at relatively low temperature and are not significantly affected by fractional crystallization. In the present study, we propose that the Al2O3 vs SiO2 and TFeO + MgO vs SiO2 diagrams can be used to distinguish leucogranites from normal granites. In addition, we report the major element compositions of the Jurassic granitic intrusions from Jingshan-Tushan-Mayishan in the Bengbu area, east-central China. Using the Al2O3 vs SiO2 and TFeO + MgO vs SiO2 diagrams and the comparison with the High Himalayan leucogranites in mineralogical and petrochemical characteristics, we suggest that the Jingshan-Tushan-Mayishan intrusions belong to a leucogranite belt. Similar to those of the High Himalayan leucogranites, the Bengbu leucogranites have low Mg# values, indicating that they resulted from low temperature dehydration partial melting of the subducted continental crust of the South China Block at the crustal depth. Supported by National Natural Science Foundation of China (Grant No. 40634023)
Rb-Sr chronology and cooling history of the Renjiawan pyroxenite intrusion in North Dabie Terrane

Yonghong Nie,Shuguang Li,

科学通报(英文版) , 1999,
Abstract: A group of Rb-Sr ages, i.e. plagioclase-whole rock (WR) isochron age of (205 ±7) Ma, hornblende-WR isochron age of (164 ±10) Ma and biotite-WR isochron age of (123.4 ±1.2) Ma, for one pyroxenite sample from Renjiawan in North Dabie Terrane (NDT) are reported. According to the closure temperature of 600°C for plageoclase and 300°C for biotite, the Renjiawan pyroxenite should intrude into the NDT before 205 Ma, and the younger Rb-Sr ages may reflect the cooling history of the intrusion or reset by the very strong Cretaceous thermal event in NDT.
Post-collisional lithosphere delamination of the Dabie-Sulu orogen
Shuguang Li,Fang Huang,Hui Li
Chinese Science Bulletin , 2002, DOI: 10.1360/02tb9063
Abstract: The consistence between the first rapid cooling time (226–219 Ma) of the untrahigh pressure metamorphic (UHPM) rocks in the Dabie Mountains and the formation time (205–220 Ma) of the syncollisional granites in the Qinling and Sulu areas suggests that the first rapid cooling and uplift of the UHPM rocks may be related to breakoff of subducted plate. Therefore the second rapid cooling and uplift (180–170 Ma) of the UHPM racks needs a post-collisional lithosphere delamination which resulted in the granitic magmatism with an age of about 170 Ma. In addition, the rapid rising of the Dabie dome in the early Cretaceous (130–110 Ma) and the corresponding large-scale magmatism in the Dabie Mountains need another lithosphere delamination. The geochronology of the post-collisional mafic-ultramafic intrusions and geological relationship between the mafic-ultramafic intrusions and granites suggest that partial melting was initiated in the mantle, and then progressively developed in the crust, suggesting a mantle upwelling underneath the Dabie Mountains. The unusual fractional trend of the gabbros characterized by lower SiO2 content (46.24%) corresponding to lower MgO content (4.53%) and their typical geochemistry features of the lower crust suggest underplating of the mantle derived magma and interaction between the magma and lower crust before their intrusion. Lithosphere delamination could be the dynamic cause of the mantle upwelling and underplating. The seismic tomography results of the Dabie Mountains and adjacent areas clearly show lithosphere thinning below the north and south sides of the Dabie Mountains. Because there is no Cenozoic magma event in the Dabie Mountains, the lithosphere thinning may result from delamination of thickened lithosphere mantle after collision. In addition, both the lower velocity zone in the 40 km depth and the basin + dome + basin coupling relationship in the Dabie Mountains also suggest the lithosphere delamination and underplating on the two sides of the orogen.
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