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A Kinematic Thermal Model for Descending Slabs with Velocity Boundary Layers

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地学前缘 2009年第S1期16卷 195-196页

作者： Keliang Zhang graduate university of the chinese academy of sciences,College of Earth science,beijing 100049,china.

Kinematic models compute the temperature distribution by prescribing a constant convergent velocity for the subducting slab,resulting in an artificial velocity discontinuity,which may accelerate the heating of subducting *** the purpose to moderate the influence of such artificial discontinuity, we construct a 2D thermal model for subduction zones with a velocity boundary layer,within which the velocities decrease linearly with the distance from the interfaces of *** are calculated

关键词： kinematic model thermal structure subduction zone velocity boundary layer finite element method

Simulations for terrestrial planets formation

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science china(Physics,Mechanics & Astronomy) 2009年第5期52卷 794-803页

作者： ZHANG Niu 1,2 &JI JiangHui 2,3 1graduate university of chinese academy of sciences,beijing 100049,china 2Purple Mountain Observatory,chinese academy of sciences,Nanjing 210008,china 3 National Astronomical Observatories,chinese academy of sciences,beijing 100012,china graduate university of chinese academy of sciences Beijing China Purple Mountain Observatory Chinese Academy of Sciences Nanjing China National Astronomical Observatories Chinese Academy of Sciences Beijing China

In this paper,the formation of terrestrial planets in the late stage of planetary formation is investigated using the two-planet *** that time,the protostar formed for about 3 Ma and the gas disk *** the model,the perturbations from Jupiter and Saturn are *** of the mass of outer planet,and the initial eccentricities and inclinations of embryos and planetesimals are also *** results show that,terrestrial planets are formed in 50 Ma,and the accretion rate is about 60%-80%.In each simulation,3-4 terrestrial planets are formed inside"Jupiter"with masses of 0.15 -3.6M⊕.In the 0.5-4 AU,when the eccentricities of planetesimals are excited,planetesimals are able to accrete material from wide radial *** plenty of water material of the terrestrial planet in the Habitable Zone may be transferred from the farther places by this *** could also happen a few times between two major planets only if the outer planet has a moderate mass and the small terrestrial planet could survive at some resonances over time scale of 10 8 *** one of our simulations,commensurability of the orbital periods of planets is very ***,a librating-circulating 3:2 configuration of mean motion resonance is found.

关键词： astrophysics exoplanet planetary formation n-body simulation

Constraints of authigenic carbonates on trace elements (Sr,Mg) of lacustrine ostracod shells in paleoenviron-ment reconstruction and its mechanism

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science china Earth sciences 2008年第5期51卷 654-664页

作者： HU Guang1,2, JIN ZhangDong1 & ZHANG Fei3 1 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, chinese academy of sciences, Xi’an 710075, china 2 graduate university of the chinese academy of sciences, beijing 100049, china 3 College of Resources and Environmental science, Nanjing Agricultural university, Nanjing 210095, china State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China graduate university of the chinese academy of sciences Beijing China College of Resources and Environmental science Nanjing Agricultural University Nanjing China

Molar ratios of Mg/Ca and Sr/Ca were measured in two species of ostracod shells preserved in the upper core (15–55 m) of the Hequing Basin in Yunnan Province, southwest china. By correlating the molar ratios between Mg/Ca and Sr/Ca and comparing them with Sr concentrations of the sediments, we suggested that: (1) the molar Mg/Ca and Sr/Ca ratio variations in respective ostracod primo reflected the changes in its ambient water composition and ecology; (2) the molar Sr/Ca ratios responded better to the salinity change linearly than Mg/Ca without aragonite precipitation in the system, and otherwise there was no linear relation between them; and (3) the molar Sr/Ca ratios were mainly controlled by salinity and authigenic carbonate precipitation, whereas the molar Mg/Ca ratios were related to both salinity and temperature. In fact, the rate of ostracod growth owing to temperature controls the fluctuation of Mg/Ca in shells. Here, more attentions should be paid to the constraint of authigenic mineral precipitation processes on the trace elements in ostracod shells and to the correlation between these trace elements in biogenic carbonates and compositions of the sediments in systems and in future in vitro experiments.

关键词： ostracod shell molar Sr/Ca ratio molar Mg/Ca ratio environmental response Heqing Basin

Interannual variability of Antarctic Oscillation and its influence on East Asian climate during boreal winter and spring

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science china Earth sciences 2006年第5期49卷 554-560页

作者： FAN Ke1,2,3 & WANG Huijun2 1. Nansen-Zhu International Research Center, Institute of Atmospheric Physics, chinese academy of sciences, beijing 100029, china 2. Department of Atmospheric science, Yunnan university, Kunming 650091, china 3. graduate university of the chinese academy of sciences, beijing 100049, china Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Department of Atmospheric science Yunnan University Kunming China graduate university of the chinese academy of sciences Beijing China

The interannual variability of Antarctic Oscillation (AAO) and its influence on East Asian climate during both boreal winter and spring are addressed. The results show that the positive AAO anomaly decreases the cold activity over East Asia during both boreal winter and spring. AAO-related barotropic meridional teleconnection from Antarctic to Arctic is found through analysis of mean me- ridional circulations. This meridional teleconnection is remarkable over Eurasia during boreal winter and over the Pacific Ocean during boreal spring. The results also show that zonal mean zonal wind at high latitudes in Southern Hemisphere has well positive correlation with that of Eurasia during boreal winter and has negative correlation with Pacific North American teleconnection (PNA) during boreal spring, which again display the meridional teleconnection. Thus, local meridional teleconnection is a possible linkage for interaction of circulations at mid-high latitudes between both hemispheres.

关键词： Antarctic Oscillation, Eurasian west wind, meridional teleconnection, mean meridional circulation.

Quasi-secure quantum dialogue using single photons

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science china(Physics,Mechanics & Astronomy) 2007年第5期50卷 558-562页

作者： YANG YuGuang1,2 & WEN QiaoYan31 College of Computer science and Technology, beijing university of Technology, beijing 100022, china 2 State Key Laboratory of Information Security, graduate university of the chinese academy of sciences, beijing 100049, china 3 School of science, beijing university of Posts and Telecommunications, beijing 100876, china College of Computer science and Technology Beijing University of Technology Beijing China State Key Laboratory of Information Security Graduate University of the Chinese Academy of Sciences Beijing China School of science Beijing University of Posts and Telecommunications Beijing China

A quasi-secure quantum dialogue protocol using single photons was proposed. Different from the previous entanglement-based protocols, the present protocol uses batches of single photons which run back and forth between the two parties. A round run for each photon makes the two parties each obtain a classical bit of information. So the efficiency of information transmission can be increased. The present scheme is practical and well within the present-day technology.

关键词： quantum dialogue, single photon, quantum secure direct communication

Valuations on arithmetic surfaces

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science china Mathematics 2009年第1期52卷 66-76页

作者： XU Ning Department of Mathematics, graduate School of chinese academy of sciences, beijing 100049, china Department of Mathematics Graduate School of Chinese Academy of Sciences Beijing China

In this paper, we give the definition of the height of a valuation and the definition of the big field ? p,G , where p is a prime and G ? ? is an additive subgroup containing 1. We conclude that ? p,G is a field and ? p,G is algebraically closed. Based on this the author obtains the complete classification of valuations on arithmetic surfaces. Furthermore, for any m ? p,G n ∈ ?, let V m,n be an ∝-vector space of dimension n - m + 1, whose coordinates are indexed from m to n. We generalize the definition of ? p,G , where p is a prime and G ? V m,n is an additive subgroup containing 1. We also conclude that ? p,G is a field if m ? 0 ? n.

关键词： valuation height rank totally ordered group big field transcendental number 14J10

Threshold quantum secure direct communication without entanglement

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science china(Physics,Mechanics & Astronomy) 2008年第2期51卷 176-183页

作者： YANG YuGuang1,3 & WEN QiaoYan2 1 College of Computer science and Technology, beijing university of Technology, beijing 100022, china 2 School of science, beijing university of Posts and Telecommunications, beijing 100876, china 3 State Key Laboratory of Information Security (graduate School of chinese academy of sciences), beijing 100049, china College of Computer science and Technology Beijing University of Technology Beijing China State Key Laboratory of Information Security (graduate School of chinese academy of sciences) Beijing China School of science Beijing University of Posts and Telecommunications Beijing China

For the first time, a threshold quantum secure direct communication (TQSDC) scheme is presented. Similar to the classical Shamir's secret sharing scheme, the sender makes n shares, S1, …, Sn of secret key K and each receiver keeps a share secretly. If the sender wants to send a secret message M to the receivers, he en-codes the information of K and M on a single photon sequence and sends it to one of the receivers. According to the secret shares, the t receivers sequentially per-form the corresponding unitary operations on the single photon sequence and ob-tain the secret message M. The shared shares may be reusable if it can be judged that there is no eavesdropper in line. We discuss that our protocol is feasible with current technology.

关键词： quantum secure direct communication threshold secure direct communication quantum secret sharing

Research on the method for retrieving soil moisture using thermal inertia model

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science china Earth sciences 2006年第5期49卷 539-545页

作者： LIU Zhenhua1 & ZHAO Yingshi2 1. Information College, South china Agricultural university, Guangzhou 510642, china 2. graduate university of chinese academy of sciences, beijing 100049, china Information College South China Agricultural University Guangzhou China graduate university of chinese academy of sciences Beijing China

In order to improve accuracy of soil moisture inversion using remote sensing, a new thermal inertia model is proposed in this paper. The improved model needs only surface maximum temperature as the temperature parameter input instead of input of the surface temperature difference, as well as the surface sensible and latent fluxes are introduced into boundary conditions of thermal conductivity equation. Furthermore, surface soil conductive heat transfer equation of two-layer model is used to solve the soil thermal inertia so that the remote sensing thermal inertia method can be ap- plied to regions with better-covered vegetation, but usually only for the bare areas or worse vegetation covered areas. The model has been tested at several locations in the area of west Inner Mongolia. Comparing the simulation of the new model with the measurements obtained by apparent thermal inertia and by field test, the result shows that the inertia thermal model can be used to estimate soil moisture in more reasonable accuracy.

关键词： thermal model, thermal conductivity equation, soil initial, sensible flux, latent flux, two-layer model.

Narrow line Seyfert 1 galaxies: where are the broad line regions?

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science china(Physics,Mechanics & Astronomy) 2010年第12期53卷 2307-2311,2339-2343页

作者： MAO WeiMing 1,2,3 , HU Chen 2 , WANG JianMin 2 , BIAN WeiHao 4 , ZHANG Shu 2 & ZHAO Gang 1 1 Key Laboratory of Optical Astronomy, National Astronomical Observatories, chinese academy of sciences, beijing 100012, china 2 Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, chinese academy of sciences, beijing 100049, china 3 graduate university of the chinese academy of sciences, beijing 100049, china 4 Department of Physics, Nanjing Normal university, Nanjing 210011, china chinese academy of sciences Key Laboratory of Optical Astronomy National Astronomical Observatories Beijing China (GRID:grid.9227.e) (ISNI:***) chinese academy of sciences Key Laboratory for Particle Astrophysics Institute of High Energy Physics Beijing China (GRID:grid.9227.e) (ISNI:***) graduate university of the chinese academy of sciences Beijing China (GRID:grid.458514.9) chinese academy of sciences Key Laboratory for Particle Astrophysics Institute of High Energy Physics Beijing China (GRID:grid.9227.e) (ISNI:***) Nanjing Normal university Department of Physics Nanjing China (GRID:grid.260474.3) (ISNI:***) chinese academy of sciences Key Laboratory of Optical Astronomy National Astronomical Observatories Beijing China (GRID:grid.9227.e) (ISNI:***)

A sample consisting of 211 narrow line Seyfert 1 galaxies (NLS1s) with high quality spectra from the Sloan Digital Sky Survey (SDSS) is selected to explore where broad line regions are in these objects. We find that the Hβ profile can be fitted well by three (narrow, intermediate and broad) Gaussian components, and the FWHM ratios of the broad to the intermediate components hold a constant of 3.0 roughly for the entire sample. If the broad components originate from the region scaled by the well-determined Hβ reverberation mapping relation, we find that the intermediate components originate from the inner edge of the torus, which is scaled by dust K-band reverberation. We find that the IC and the BC are strongly linked dynamically, but the relation of their covering factors is much more relaxed, implying that both regions are clumpy.

关键词： black hole physics galaxies: evolution quasars: general