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Genetic structure and phylogeography of a relict tree fern,Sphaeropteris brunoniana (Cyatheaceae) from china and Laos inferred from cpDNA sequence variations:Implications for conservation

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Journal of Systematics and Evolution 2011年第1期49卷 72-79页

作者： 1,2.Zi-Juan WANG 1 Kai-Yun GUAN 1 (Kunming Institute of Botany, chinese academy of Sciences, Kunming 6502.4,{2.) 2.({3. university of chinese academy of Sciences, beijing 100049,{2.) (Kunming Institute of Botany Chinese Academy of Sciences Kunming 650204 China) (graduate university of {2. {3. of Sciences Beijing 100049 China)

In this study, we analyzed the genetic structure and phylogeography of Sphaeropteris brunoniana from china and Laos. Combining cpDNA trnL-trnF and atpB-rbcL sequence variations, five haplotypes were identi- fied from the 10 investigated populations. Moderate haplotype diversity (h = 0.66580) and low nucleotide diver- sity (π = 0.2.1}× 10 ?3.) were detected. The S. brunoniana in Yunnan region had much higher genetic diversity (h = 0.60195, π = 0.3. × 10 ?3.) than that of Hainan–Laos (h = 0.00000, π = 0.00). A high level of genetic differentiation (94.74%) between the two regions was revealed by AMOVA. Nested clade analysis identified two major clusters of the five haplotypes, one clade in the Yunnan region and the other in Hainan–Laos. The analysis indicated that restricted gene flow with isolation by distance and allopatric fragmentation were likely the major processes that shaped the spatial distribution of the haplotypes. The isolated distribution of clades implied the emergence of independent refugia of this species in each region during Quaternary glaciations. The Yunnan populations frequently contained an ancestral haplotype, and most of them harbored other descendent haplotypes. Based on the distribution pattern of haplotypes and the nested clade analysis results, the Yunnan region potentially had several refugia of this species during glacial periods, whereas the Hainan populations were probable new colonizations.

关键词： atpB-rbcL Hainan–Laos phylogeography Sphaeropteris brunoniana trnL-trnF Yunnan.

A formal model of fair exchange protocols

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Science in china(Series F) 2005年第4期48卷 499-512页

作者： QING Sihan1,2.3.& LI Gaicheng1,2.3.1. Engineering Research Center for Information Security Technology, Institute of Software, {2. Aca- demy of Sciences, beijing 100080, china 2. beijing Zhongke Ansheng Corporation of Information Technology, beijing 100080, china 3. graduate School of the {2. academy of Sciences,{12., china Engineering Research Center for Information Security Technology Institute of Software Chinese Academy of Sciences Beijing China beijing Zhongke Ansheng Corporation of Information Technology Beijing China graduate School of the chinese {2. of Sciences Beijing China

Based on the study of existing fair exchange protocols, this paper sets up an accurate formal model by stepwise refinement. In the process of refinement an unreliable channel is employed to simulate an attack behavior. The model provides a novel formal definition of exchanged items, and presents the formal goals for fairness, accountability, etc., reflecting the inherent requirements for fair exchange protocols across-the-board. In order to check, prove, and design fair exchange protocols effectively and efficiently, the model puts forward a novel property of abuse-freeness which applies to all fair exchange protocols, gives a formal definition for trust strand of the third party, and presents general criteria of designing a secure and effective fair exchange protocol. Taking a typical fair exchange protocol as an example, this paper presents the analysis steps of fair exchange protocols appealing to our model. An unknown attack is uncovered. The analysis reveals the process of a complete attack, discovering deeper reasons for causing an attack. Finally, we modify the flawed protocol and the revised protocol ensures the desirable properties.

关键词： events local causal relation local temporal relation global relation exchanged item security goals.

Some properties on multivariate filter banks with a matrix factorization

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Progress in Natural Science:Materials International 2005年第2期15卷 20-30页

作者： LIAN Qiaofang1, XIAO Hongying2. and CHEN Qiuhui3.1. Department of Mathematics, beijing Jiaotong {2., beijing 100044,{3. 2. Institute of Mathematics, academy of Mathematics and System Sciences, chinese academy of Sciences, beijing 100080,{3. 3. Department of Scientific Computing and Computer Applications, Zhongshan {2., Guangzhou 5102.5,{3.) Dept. of Mathematics Beijing Jiaotong Univ. Beijing 100044 China Inst. of Mathematics Acad. of Math. and System Sci. Chinese Acad. of Sciences Beijing 100080 China Dept. of Scientific Computing Zhongshan Univ. Guangzhou 510275 China

A class of multivariate filter banks with a matrix factorization has been developed by Chen et al. The main purpose of this paper is to discuss some further properties of this kind of filter bank, such as the completeness, accuracy of the corresponding scaling functions and the relationships with Daubechies' wavelets and the multi-wavelets provided by Chui and Lian. Moreover, some examples are given to show that this kind of filter bank has a higher accuracy for the scaling functions.

关键词： filter banks completeness accuracy matrix factorization

CO observations of massive star forming regions at different evolutionary phases

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Science china(Physics,Mechanics & Astronomy) 2006年第5期49卷 626-640页

作者： CHEN Xi1,2. XU Ye1,3. SHEN Zhiqiang1,3.& LI Jingjing1,2.1. Shanghai Astronomical Observatory, {2. academy of Sciences, Shanghai 2.003., china 2. {3. School of the {2. academy of Sciences, beijing 10003., china 3. Joint Institute for Galaxy and Cosmology, Shanghai Astronomical Observatory and the {12. of Science and Technology of china, Shanghai 2.003., china Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai China graduate School of the chinese {2. of Sciences Beijing China Joint Institute for Galaxy and Cosmology Shanghai Astronomical Observatory and the University of Science and Technology of China Shanghai China

The 12.O (J=1-0), 13.O (J=1-0) and C18O (J=1-0) emissions in 9 massive star forming regions, which are believed to be at different stages of massive star formation, were mapped with the 13.7 m millimeter wave telescope at Qinghai Station of Purple Mountain Observatory. Of the observed 9 sources, 13.O cores were detected in seven of them, and C18O cores in five of them. And only two sources associated with C18O cores and H2. masers showed the extended structures and strong outflows. This is the first detection of outflow associated with IRAS 2.566+582. in the observing field of S152.S153. The physical parameters of cores and outflows for these sources, derived from Local Thermal Equilibrium (LTE) analysis, are presented. These observing results suggest that the C18O cores will only appear when the gas density is high enough and the probability to have an outflow is very high when the clumps show the C18O and H2. maser simulta- neously.

关键词： star formation cloud core outflow H2. maser

Estimating surface evapotranspiration using combined MODIS and CBERS-02.data

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Science china(Technological Sciences) 2005年第S2期48卷 145-160页

作者： XIN Xiaozhou1,2. LIU Qinhuo1, TANG Yong1,3. TIAN Guoliang1, GU Xingfa1, LI Xiaowen1,2. ZHENG Hongsheng4 & CHEN Jiayi4 1. State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing Applications, chinese {2. of Sciences, beijing 100101,{3. 2. Research Center for Remote Sensing and GIS, Department of Geography, beijing Normal university, beijing 100875,{3. 3. graduate university of chinese {2. of Sciences, beijing 10003.,{3. 4. Department of Atmospheric Physics, Peking university, beijing 100871,{3. State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing 100101 China Research Center for Remote Sensing and GIS Department of Geography Beijing Normal University Beijing 100875 China graduate university Chinese Academy of Sciences Beijing 100039 China Department of Atmospheric Physics Peking University Beijing 100871 China

Spatial scale error is one of the most serious problems in the estimates of land surface heat fluxes of sensible and latent from satellite-borne data such as MODIS 1km resolution reflectance and emissive data. One of the feasible and economic ways to decrease the spatial scale error is to use high resolution land use class data together with the MODIS data. CBERS-02.data were used to produce land use class of Baiyangdian area, Hebei Province, china in the autumn of 2.04. The area ratio of each class in MODIS pixel was calculated, and used to derive the heat fluxes of the mixed pixel. The results showed that the estimated heat fluxes of soil, sensible and latent have been changed remarkably after using the high resolution land class data. It could be concluded from the comparison between simulated and ground-measured fluxes as well as the theoretical analysis that high resolution land class data are useful to diminishing the scale error of heat fluxes estimated from low resolution satellite data.

关键词： surface evapotranspiration spatial scale error MODIS CBERS land class.

Prediction method for October 2.03.solar storm

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Science china(Technological Sciences) 2006年第5期49卷 629-640页

作者： XIE Yanqiong1, 2. 3. WEI Fengsi1, FENG Xueshang1 & ZHONG Dingkun1, 2.1. State Key Laboratory of Space Weather, Center for Space Science and Applied Research, chinese {2. of Sciences, beijing 100080,{3. 2. graduate School, chinese {2. of Sciences, beijing 10003.,{3. 3. Institute of Meteorology, PLA university of Science and Technology, Nanjing 2.1101,{3. State Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China graduate School Chinese Academy of Sciences Beijing China Institute of Meteorology PLA University of Science and Technology Nanjing China

Aiming at two intense shock events on October 2. and 2., 2.03. this paper presents a two-step method, which combines synoptic analysis of space weather ——“observing” and quantitative prediction ——“palpating”, and then uses it to test predictions. In the first step of “observing”, on the basis of observations of the solar source surface magnetic field, interplanetary scintillation (IPS) and ACE spacecraft, we find that the propagation of the shocks is asymmetric relative to the normal direction of their solar sources, and the Earth is located near the direction of the fastest speed and the greatest energy of the shocks. As the two fast ejection shock events, the fast explosion of coronal mass of the extremely high temperature, the strong magnetic field, and the high speed background solar wind are also helpful to their rapid propagation. In the second step of “palpating”, we adopt a new membership function of the fast shock events for the ISF method. The predicted results show that for the onset time of the geomagnetic disturbance, the relative errors between the observational and the predicted results are 1.8% and 6.7%; and for the magnetic disturbance magnitude, the relative errors are 4.1% and 3.1%, re- spectively. Furthermore, the comparison among the predicted results of our two-step method with those of five other prevailing methods shows that the two-step method is advantageous. The results tell us that understanding the physical features of shock propagation thoroughly is of great importance in improving the prediction precision.

关键词： solar storm, interplanetary shock, interplanetary scintillation, two-step method, ISF method.

Applications of URANS on predicting unsteady turbulent separated flows

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Acta Mechanica Sinica 2009年第3期25卷 319-324页

作者： Jinglei Xu Huiyang Ma Department of Physics, graduate university of the {2. {3. of Sciences, 100049 beijing, china Department of Physics Graduate University of the Chinese Academy of Sciences Beijing China

Accurate prediction of unsteady separated turbulent flows remains one of the toughest tasks and a practi cal challenge for turbulence modeling. In this paper, a 2. flow past a circular cylinder at Reynolds number 3.900 is numerically investigated by using the technique of unsteady RANS （URANS）. Some typical linear and nonlinear eddy viscosity turbulence models （LEVM and NLEVM） and a quadratic explicit algebraic stress model （EASM） are evaluated. Numerical results have shown that a high-performance cubic NLEVM, such as CLS, are superior to the others in simulating turbulent separated flows with unsteady vortex shedding.

关键词： URANS Nonlinear eddy viscosity turbulencemodel ,Separated flows Circular cylinder

Experimental and discrete element numerical analysis of side slope instability induced by fissure water underlying impervious bed

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Science china(Technological Sciences) 2005年第Z1期48卷 65-80页

作者： LIU Bingshan1, LI Shihai1, ZHANG Lei1,2.& WANG Jianguo3.. Institute of Mechanics, chinese {2. of Sciences, beijing 100080,{3. 2. graduate School, chinese {2. of Sciences, beijing 100060,{3. 3. Tropical Marine Science Institute, National university of Singapore, 10 Kent Ridge Crescent, Singapore 1192.0 Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China graduate School Chinese Academy of Sciences Beijing 100060 China Tropical Marine Science Institute National University of Singapore 10 Kent Ridge Crescent Singapore 119260 Singapore

When the sliding mass contains impervious bed, rainfall can infiltrate into mountain via crevices and form higher artesian aquifer at impervious bed inferior. This will decrease slip resistance and increase sliding forces of the sliding mass, thus lowering the safety factor, and inducing landslide disasters. In this paper, a landslide experimental apparatus is designed for experimental studies on the mechanism of this type of landslides. Meanwhile, the non-dimensional parameters in the model experiment are taken into account using dimensional analysis. The experimental results show that (1) the ratio of the cleft water pressure to the overlying pressure is a crucial parameter affecting the stability of the slope; (2. when the shut-in pressure reaches 80% of the normal component of the pressure on the slip surface made up of rock and soil, landslide will occur; (3. the whole slope will start to slide when the shut-in pressure is equal to the normal component of the pressure formed by the overlying rock and soil on the upper 3.% area. In this article, a discrete element method simulation is used to investigate the influence of cleft water pressure and shearing strength on the landslide stability. It can be concluded that the critical value of Ccr, ?cr, which determines the slide mass stability, increases with the increase of the water pressure; if the water pressure reaches a high level, the stability of the slide mass depends mainly on C, while the influence of ? becomes smaller than C.

关键词： impervious bed, rainfall infiltration, pore water pressure, landslide experiment, displacement monitor, discrete element method.

Simulation of aerodynamic performance affected by vortex generators on blunt trailing-edge airfoils

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Science china(Technological Sciences) 2010年第1期53卷 1-7页

作者： YANG Ke1,2.ZHANG Lei1,3.& XU JianZhong1,2.1 Institute of Engineering Thermophysics,chinese {2. of Sciences,beijing 100190,{3. 2.Key Laboratory of Wind Energy Utilization,chinese {2. of Sciences,beijing 100190,{3. 3.graduate School of chinese {2. of Sciences,beijing 100190,{3. Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China Key Laboratory of Wind Energy Utilization Chinese Academy of Sciences Beijing China graduate School of chinese {2. of Sciences Beijing China

An investigation was carried out by numerical simulation on a wind turbine airfoil and a blunt trailing-edge airfoil with and without vortex generators (VGs), and the performance of the airfoils was analyzed. By the simulation of airfoil DU 91-W2.2.0 it was verified that the numerical method and model were credible. Based on this airfoil, a new one with a blunt trailing edge of 6% chord was blended by symmetrically adding thickness, and its characteristics curves were obtained through computing at key angles of attack. Additionally, the pressure distribution on blended airfoil was analyzed by comparing to the airfoil without blend. The interaction of streamwise vortices induced by VGs with trailing vortex or separation vortex was considered, followed by the uncovery of how VGs can suppress the boundary layer separation.

关键词： vortex generators airfoil blunt trailing-edge