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Two possible mechanisms for vortex self-organization

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science China Earth sciences 2006年第2期49卷 202-211页

作者： LUO Zhexian2, ZHOU Xiuji1 & GAO Shouting3.1. chinese academy of Meteorological sciences,{3. 100081, China 2. Department of.space Information science, Nanjing University of Information science.and Technology, Nanjing 210044, China 3. Institute of Atmospheric Physics, chinese academy of.science.,{3. 100029, China 2. Department of Environmental science Nanjing University of Information Science and Technology Nanjing 210044 China 1. chinese academy of Meteorological sciences Beijing 100081 China 3. Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The vortex self-organization is investigated in this paper by four groups of numerical experiments within the framework of quasi-geostrophic model, and based on the experimental results two types of possible mechanisms for vortex self-organization are suggested. The meso-scale to-pography may enable separated vortices to merge into a larger scale vortex; and the interaction of meso-γ and meso-β scale systems may make separated vortices to self organize a typhoon-like vor-tex circulation.

关键词： vortex, self-organization, meso-scale topography, interaction of different scales.

A tentative study for the prediction of the CME related geomagnetic storm intensity and its transit time

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science China(Technological sciences) 2005年第6期48卷 648-668页

作者： ZHAO Xinhua1,2 & FENG Xueshang1,3.1. SIGMA Weather Group, Key Laboratory of.space Weather, Center for space science.and {3.ied Re-search, chinese academy of.science., beijing 100080, China 2. Graduate School of the chinese academy of.science., beijing 10003., China 3. School of Geophysics and Geoinformation Systems, China University of Geosciences, beijing 100083. China 1. SIGMA Weather Group Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences 100080 Beijing China 2. Graduate School of the chinese academy of.science. 100039 Beijing China 3. School of Geophysics and Geoinformation Systems China University of Geosciences 100083 Beijing China

Using 80 CME-ICME events during 1997.1―2002.9, based on the eruptive source locations of CMEs and solar magnetic field observation at the photosphere, a current sheet magnetic coordinate (CMC) system is established in order to study the propagation of CME and its geoeffectiveness. In context of this coordinate system, the effect of the eruptive source location and the form of heliospheric current sheet (HCS) at the eruptive time of CME on the geomagnetic storm intensity caused by CME and the CME’s transit time at the Earth is investigated in detail. Our preliminary conclusions are: 1) The geomagnetic disturbances caused by CMEs tend to have the so-called “same side-opposite side effect”, i.e. CMEs erupt from the same side of the HCS as the earth would be more likely to arrive at the earth and the geomagnetic disturbances associated with them tend to be of larger magnitude, while CMEs erupting from the opposite side would arrive at the earth with less probability and the corresponding geomagnetic disturbance magnitudes would be relatively weaker. 2) The angular separation between the earth and the HCS affect the corresponding disturbance intensity. That is, when our earth is located near the HCS, adverse{3. weather events occur most probably. 3. The erupting location of the CME and its nearby form of HCS will also affect its arrival time at the earth. According to these conclusions, in this context of CMC coordinate we arrive at new prediction method for estimating the geomagnetic storm intensity (Dstmin) caused by CMEs and their transit times. The appl.cation of the empirical model for 80 CME-ICME events shows that the relative error of Dst is within 3.% for 59% events with Dstmin≤?50 nT, while the averaged absolute error of transit time is lower than 10 h for all events.

关键词： coronal mass ejections, current sheet magnetic coordinate system, geomagnetic storm intensity, transit time, prediction method.

Wavelet Analysis of the Schwabe Cycle Properties in Solar Activity

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chinese Journal of Astronomy and Astrophysics 2004年第6期4卷 578-582页

作者： Gui-Ming LeNational Astronomical Observatories, chinese academy of.science., beijing 100012 Center for space{3. applied Research Center, chinese academy of.science., beijing 100080 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 []Center for Space Science and Applied Research Center Chinese Academy of Sciences Beijing 100080

Properties of the Schwabe cycles in solar activity are investigated by using wavelet transform. We study the main range of the Schwabe cycles of the solar activity recorded by relative sunspot numbers, and find that the main range of the Schwabe cycles is the periodic span from 8-year to 14-year. We make the comparison of 11-year’s phase between relative sunspot numbers and sunspot group numbers. The results show that there is some difference between two phases for the interval from 1710 to 1810, while the two phases are almost the same for the interval from 1810 to 1990.

关键词： sun sunspot sun activity method data analysis

Prediction method for October 2003.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 {3.ied Research, chinese academy of.science., beijing 100080, China 2. Graduate School, chinese academy of.science., beijing 10003., China 3. Institute of Meteorology, PLA University of science.and Technology, Nanjing 211101, China State Key Laboratory of.space Weather Center for Space Science applied Research Chinese Academy of Sciences Beijing 100080 China Graduate School Chinese Academy of Sciences Beijing 100039 China Institute of Meteorology PLA University of Science Technology Nanjing 211101 China

Aiming at two intense shock events on October 28 and 29, 2003. 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.

Modeling and verifying Web services driven by requirements:An ontology-based approach

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science in China(Series F) 2006年第6期49卷 792-820页

作者： HOU Lishan1,3.JIN ZHi1,2 & WU Budan1,4 1. academy of Mathematics and Systems science, chinese academy of.science.,{3., China 2. Institute of Computing Technology, chinese academy of.science.,{3., China 3. Institute of Software, chinese academy of.science.,{3., China 4. Graduate University of chinese academy of.science., beijing 100049, China 1. academy of Mathematics and Systems science Chinese Academy of Sciences Beijing 100080 China 3. Institute of Software Chinese Academy of Sciences Beijing 100080 China 2. Institute of Computing Technology Chinese Academy of Sciences Bejing 100080 China 4. Graduate University of chinese academy of.science. Beijing 100049 China

Automatic discovery and composition of Web services is an important research area in Web service technology, in which the specification of Web services is a key issue. This paper presents a Web service capability description framework based on the environment ontology. This framework depicts Web services capability in two aspects： the operable environment and the environment changes resulting from behaviors of the Web service. On the basis of the framework, a requirement-driven Web service composition model has been constructed. This paper brings forward the formalization of Web service interactions with π calculus. And an automatic mechanism converting conceptual capability description to the formal process expression has been built. This kind of formal specification assists in verifying whether the composite Web service model matches the requirement.

关键词： Web service environment ontology automatic composition π calculus formal verification.

Effect of rock mass structure and block size on the slope stability——Physical modeling and discrete element simulation

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science China(Technological sciences) 2005年第z1期48卷 1-17页

作者： LI Shihai1, LIAN Zhenzhong1,2 & J. G. Wang3.1. Institute of Mechanics, chinese academy of.science., beijing 100080, China 2. Graduate School, chinese academy of.science.,{3. 100060, China 3. Tropical Marine science Institute, National University of Singapore, Singapore 119260 chinese Acad Sci Inst Mech Beijing 100080 Peoples R China chinese Acad Sci Grad Sch Beijing 100060 Peoples R China Natl Univ Singapore Trop Marine Sci Inst Singapore 119260 Singapore

This paper studies the stability of jointed rock slopes by using our improved three-dimensional discrete element methods (DEM) and physical modeling. Results show that the DEM can simulate all failure modes of rock slopes with different joint configurations. The stress in each rock block is not homogeneous and blocks rotate in failure development. Failure modes depend on the configuration of joints. Toppling failure is observed for the slope with straight joints and sliding failure is observed for the slope with staged joints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considering the joints in rock masses, the LEM predicts much higher factor of safety than physical modeling and DEM. The failure mode and factor of safety predicted by the DEM are in good agreement with laboratory tests for any jointed rock slope.

关键词： rock masses, slope stability, DEM simulation, block size effect, joints configuration effect, limit equilibrium method.

Review on the study of entanglement in quantum computation speedup

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chinese science Bulletin 2007年第16期52卷 2161-2166页

作者： DING ShengChao1,3.& JIN Zhi1,2,1 Institute of Computing Technology,chinese academy of.science.,{3. 100080,China 2 academy of Mathematics and Systems science,chinese academy of.science.,{3. 100080,China 3.Graduate University of chinese academy of.science.,{3. 100080,China Institute of Computing Technology Chinese Academy of Sciences Beijing 100080 China

The role the quantum entanglement plays in quantum computation speedup has been widely disputed. Some believe that quantum computation's speedup over classical computation is impossible if entan-glement is absent,while others claim that the presence of entanglement is not a necessary condition for some quantum algorithms. This paper discusses this problem systematically. Simulating quantum computation with classical resources is analyzed and entanglement in known algorithms is reviewed. It is concluded that the presence of entanglement is a necessary but not sufficient condition in the pure state or pseudo-pure state quantum computation speedup. The case with the mixed state remains open. Further work on quantum computation will benefit from the presented results.

关键词：量子论量子纠缠量子计算加速模拟

Quasi-likelihood estimation of average treatment effects based on model information

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science China Mathematics 2007年第1期50卷 1-12页

作者： Zhi-hua SUN academy of Mathematics and Systems science, chinese academy of.science.{3., China 1. academy of Mathematics and Systems science Chinese Academy of Science Beijing 100080 China

In this paper, the estimation of average treatment effects is considered when we have the model information of the conditional mean and conditional variance for the responses given the covariates. The quasi-likelihood method adapted to treatment effects data is developed to estimate the parameters in the conditional mean and conditional variance models. Based on the model information, we define three estimators by imputation, regression and inverse probability weighted methods. All the estimators are shown asymptotically normal. Our simulation results show that by using the model information, the substantial efficiency gains are obtained which are comparable with the existing estimators.

关键词： average treatment effects inverse probability weighted quasi-likelihood unconfounded assignment treatment model information 62G18

The gravity wave instability induced by photochemistry in summer polar mesopause region

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chinese science Bulletin 2000年第3期45卷 267-272页

作者： Center for space science.and applied Research,{3., beijing 100080, China Laboratory of Numeric Study of Heliospheric Physics,{3., beijing 100080, China Center for space science.and applied Research Chinese Academy of Sciences Beijing China Laboratory of Numeric Study of Heliospheric Physics Chinese Academy of Sciences Beijing China

The effect of diabatic process due to the photochemical heating and cooling on the gravity wave propagation in middle atmosphere is studied. A linear gravity wave model which considers the diabatic process is established. The unstable region and the growth rate of the gravity wave caused by photochemistry are calculated. And the comparison between the model and the adiabatic gravity wave theory of pure dynamics is made. The results indicate that the photochemical heating process can induce the instability of gravity wave at mesopause. The intensity of the instability becomes stronger as the temperature decreases. The temperature feature and the altitude characteristics of the instability are consistent with the observation. Therefore, the instability of the gravity wave induced by photochemistry may be an important mechanism in polar mesopause region in summer.

关键词： photochemistry instability gravity wave growth rate.