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

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 Applied Re-search, Chinese Academy of Sciences, beijing 100080, China 2. Graduate school of the Chinese Academy of Sciences, 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 Sciences 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 space 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 application 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.

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A heuristic path-estimating algorithm for large-scale real-time traffic information calculating

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Science China(Technological Sciences) 2008年第S1期51卷 165-174页

作者： L WeiFeng1,ZHU TongYu1,WU DongDong2,DAI Hong3.& HUANG Jian1 1 State Key Laboratory for Software Development Environment,beihang university,beijing 100083.China 2 beijing Transportation Information Center,beijing 100055,China 3.College of Arts & Science,beijing Union university,beijing 100083.China 1. State Key Laboratory for Software Development Environment Beihang University Beijing 100083 China 2. beijing Transportation Information Center Beijing 100055 China 3. College of Arts & Science Beijing Union University Beijing 100083 China

As the original Global Position System (GPS) data in Floating Car Data have the accuracy problem,this paper proposes a heuristic path-estimating algorithm for large-scale real-time traffic information calculating. It uses the heuristic search method,imports the restriction with geometric operation,and makes comparison between the vectors composed of the vehicular GPS points and the special road network model to search the set of vehicular traveling route candidates. Finally,it chooses the most optimal one according to weight. Experimental results indicate that the algorithm has considerable efficiency in accuracy (over 92.7%) and com-putational speed (max 8000 GPS records per second) when handling the GPS tracking data whose sampling rate is larger than 1 min even under complex road network conditions.

关键词： path-estimating floating car data (FCD) road network vector GPS

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Quasi-equality constrained risk-sensitive filtering for nonlinear discrete-time systems

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控制理论与应用（英文版） 2012年第2期10卷 229-235页

作者： Linfeng SHEN, Yan LIN school of Automation Science and Electrical Engineering, beijing university of Aeronautics and Astronautics, {3., China school of Automation Science and Electrical Engineering Beijing University of Aeronautics and Astronautics Beijing China

More and more data fusion models contain state constraints with valuable information in the filtering process. In this study, an optimal filter of risk sensitive with quasi-equality constraints is formulated using the reference probability method. Through recursion processes of probability density acquired from the probability measure change, the derived algorithm is optimal in the sense of the risk sensitive parameter. The system and constraint models are Consistent in statistics. Simulation results show that it is more robust and efficient than projection filters for the worst-case of noises and model uncertainty.

关键词： Optimal estimation Risk-sensitive filtering Constraints

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Petrogenesis of Songshugou dunite body in the Qinling orogenic belt, Central China: Constraints from geochemistry and melt inclusions

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Science China Earth Sciences 2005年第8期48卷 1146-1157页

作者： SU Li1,2, SONG Shuguang3.& ZHOU Dingwu1 1. Key Laboratory of Continental Dynamics of the Ministry of Education, Department of Geology, Northwestern university, Xi’an 710069, China 2. The Geological Lab Center, China university of Geosciences (beijing), beijing 100083. China 3. Key Laboratory of Orogenic Belts of the Ministry of Education, Department of Geology, Peking university, beijing 100871, China 1. Key Laboratory of Continental Dynamics of the Ministry of Education Department of Geology Northwestern University 710069 Xi’an China 2. The Geological Lab Center China University of Geosciences 100083 (Beijing)Beijing China 3. Key Laboratory of Orogenic Belts of the Ministry of Education Department of Geology Peking University 100871 Beijing China

The Songshugou dunite body, which occupies an area of about 20 km2, is the largest ultramafic massif in the eastern Qinling orogenic belt, Central China. The major compo-nent of this body is dunitic rocks including mylonitic dunite and coarse-grained dunite; they oc-cupy about 95 vol% of the total body. Petrography, mineral composition, major and trace ele-ments and primitive melt inclusions have been investigated in this paper; all revealed that this dunite body is the product of melt-rock interaction by porous percolation flow. In comparison with dunite sills or veins in harzburgite from the basal part of Oman ophiolite, this dunite body is characterized by lower contents of Al2O3. CaO and HREE but higher content of highly incom-patible elements and Zr and Hf. The LREE enriched patterns and primitive mantle normalized spidergrams of trace elements are also different from the Oman dunite. Combining with melt in-clusions observed in olivines, we conclude that this dunite body is the product of large- scale porous percolation flow of high-MgO melts within depleted mantle peridotites. The high-MgO magma, in essence, was most probably produced at the hot head of an upwelling mantle plume. The occurrence of the Songshugou dunite body is closely associated with the activity of mantle super-plume in Neo-Proterozoic era in the Yangtze Craton.

关键词： Songshugou dunite body, geochemistry, melt inclusion, mantle plume, Qinling orogenic belt.

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Development and application of ergodicity model with FRCM and FLAR for hydrological process

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Science China(Technological Sciences) 2009年第2期52卷 379-386页

作者： WANG HongRui1, FENG QiLei2, LIN Xin3.& ZENG WenYi4 1 College of Water Science, Key Laboratory for Water and Sediment Sciences of the Ministry of Education, beijing Normal university, beijing 100875, China 2 {3. of Science, beijing Institute of Education, beijing 100011, China 3.school of Mathematical Sciences, beijing Normal university, beijing 100875, China 4 College of Information Science and Technology, beijing Normal university, beijing 100875, China 1. College of Water Science Key Laboratory for Water and Sediment Sciences of the Ministry of Education Beijing Normal University Beijing 100875 China 2. school of Science Beijing Institute of Education Beijing 100011 China 3. school of Mathematical Sciences Beijing Normal University Beijing 100875 China 4. College of Information Science and Technology Beijing Normal University Beijing 100875 China

In this paper, a new ergodic property analysis model of hydrological process is proposed based on fuzzy-rough c-means clustering (FRCM), autocorrelogram, and fuzzy least absolute regression (FLAR). A precipitation time series (1951―2004) from Shanghai Hydrology Station is then analyzed with the model. The results show that the precipitation time series of April, May, June, and September has er-godic property. We conclude that in the long run, the precipitation of April, May, June, and September will not keep decreasing; it will converge to its mean value in some period.

关键词： hydrological process ergodic autocorrelogram fuzzy-rough c-means clustering fuzzy least absolute regression

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A novel endorectal RF coil for high resolution MRI and spectroscopy of the prostate

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Progress in Natural Science:Materials International 2005年第5期15卷 472-476页

作者： ZHANG Hongjie 1,2, SONG Xiaoyu1, WANG Xiaoying3. XU Pingfang1 and BAO Shanglian1*(1. beijing Key Laboratory of Medical Physics & Engineering, Peking university, beijing 100871, China 2. Navy General Hospital, beijing 10003., China 3. Peking university First Hospital, beijing 10003., China) beijing Key Laboratory of Medical Physics & Engineering Peking University Beijing 100871 China Navy General Hospital Beijing 100037 China Peking university First Hospital Beijing 100034 China

The diagnosis of prostate diseases by magnetic resonance imaging (MRI) in vivo is sometimes difficult for the lower signal to noise ratio (SNR). To increase the SNR of the prostate image, we designed a RF coil that can be inserted into rectum and was named endorectal coil. The properties of RF coil were evaluated using a network analyzer. Moreover the images and spectroscopy of a special phantom were acquired and the results were compared to those of the commercial TORSO coil (G.E. Medical Systems, USA). Our coil gave a significantly higher SNR at the region of interest (ROI). The achieved high local SNR and resulting high spatial resolution would add more anatomic and biochemical information to the diagnosis of prostate diseases.

关键词： MRI RF coil endorectal coil.

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Effect of dendrite arm spacing and the γ' phase size on stress rupture properties of Ni_3.l-base single crystal superalloy IC6SX

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Science China(Technological Sciences) 2010年第6期53卷 1460-1465页

作者： JIANG LiWu1,LI ShuSuo1,WU MeiLing1 & HAN YaFang1,2 1 school of Materials Science and Engineering,beihang university,beijing 100191,China 2 {3. Institute of Aeronautical Materials,{3. 100095,China 1. school of Materials Science and Engineering Beihang University Beijing 100191 China2. Beijing Institute of Aeronautical Materials Beijing 100095 China

The effect of dendrite arm spacing and the size of γ' phase on stress rupture properties of as-cast Ni3.l-based single crystal superalloy IC6SX was *** has been found that the stress rupture properties were affected by dendrite arm spacing and the size of γ' phase significantly,i.e.,the stress rupture lives of as-cast specimens under the test condition of 1100°C/120 MPa were significantly increased from about 10 h to 3. h with decreasing dendrite arm spacing and the size of γ' phase from 3.0 μm and 1.6 μm to 1.3.μm and 0.8 μm,*** creep cracks generated easily in the brittle Y-NiMo *** the cracks gradually mergered and grew up during creep,and finally led to specimens *** orientated coarsening of γ' phase has been found in the stress ruptured specimens,due to the elements ***,the γ' phase did not form the integrated structure during the short periods of 10-3. h as the creep tests lasted.

关键词： dendrite arm spacing size of γ’ phase Ni3.l-based single crystal stress rupture property

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Zhang-Xuan thermal uplift and its genesis

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Progress in Natural Science:Materials International 2005年第8期15卷 725-732页

作者： SHAO Ji'an1*, NIU Shuyin2, ZHANG Lüqiao3.and LI Hongyang2(1. school of Earth and Space Sciences, Peking university, beijing 100871, China 2. Shijiazhuang university of Economics, Shijiazhuang 05003., China 3. Geological Bureau of Inner Mongolia, Huhhot 010020, China) school of Earth and Space Sciences Peking University Beijing 100871 China. Shijiazhuang university of Economics Shijiazhuang 050031 China. Geological Bureau of Inner Mongolia Huhhot 010020 China

Based on the researches of the Mesozoic thermal evolution history, the deformed structures, and fission track analysis of the Zhangjiakou-Xuanhua area, we obtained the following knowledge: the area experienced in 140 Ma an underplating which is marked by emplacement of mantle derived magma; during 13.—110 Ma a series of eruptions and intrusions happened, and during 80—10 Ma a rising process occurred which is synchronous with the adjacent Taihang and Yanshan Mountains and was accompanied by a series of structures down slipping from the just formed Zhang-Xuan uplift toward its periphery. Combining the Zhang-Xuan thermal lift with the large detachment structure in Baoding depression of the North China Basin in the Late Mesozoic confirms that an even larger extensional tectonic background existed in North China during this period.

关键词： Zhang-Xuan area underplating thermal uplift fission track extensional structure.

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Indian Ocean-MORB-type isotopic signature of Yushigou ophiolite in North Qilian Mountains and its implications

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Science China Earth Sciences 2006年第6期49卷 561-572页

作者： HOU Qingye1,2, ZHAO Zhidan1,2, ZHANG Hongfei3. ZHANG Benren3.& CHEN Yuelong2 1. State Key Laboratory of Geological Processes and Mineral Resources, China university of Geosciences, beijing 100083. China 2. school of Earth Science and Mineral Resources, China university of Geosciences, beijing 100083. China 3. Faculty of Earth Sciences, China university of Geosciences, Wuhan 43.074, China 1. State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083 China 2. school of Earth Science and Mineral Resources China University of Geosciences Beijing 100083 China 3. Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China

In order to explore the disputed issue concerning the tectonic affinity ofthe ancient ocean mantle of North Qilian Mountains (NQM), geochemical and Sr, Nd, Pb isotopiccompositions of pillow basalts of the Yushigou Ophiolite (YSGO) suite from NQM have been analyzedsystematically. The pillow basalts exhibit tholeiitic characteristics, with flatchondrite-normalized REE patterns ((La/Yb)_N = 0.98—1.27). They display no Nb, Ta, Zr, Hf negativeanomalies, and show MORB features in 2Nb-Zr/4-Y and Ti/100-Zr-YX3.tectonic discrimination *** results indicate that the Yushigou ophiolite is most likely to be formed in a mid-ocean ridgeor mature back-arc basin. Their isotopic data show a relatively broad and enriched ^(87)Sr/^(86)Sr(0.70509 — 0.70700), restricted ^(143.Nd/^(144)Nd (0.512955-0.512978). Pb isotopes are in the rangeof ^(206)Pb/^(204)Pb (18.054-20.562), ^(207)Pb/^(204)Pb (15.53.-15.743. and ^(208)Pb/^(204)Pb(3..068-3..53.). These isotopic data imply that the basalts originated from the depleted mantle(DMM), with the involvement of enriched mantle components (mainly EMII). Geochemical comparisonsbetween the basalts in YSGO and the MORB-type basalts of ophiolite suites occurring in the knownancient Tethyan tectonic domain indicate that the ancient oceanic mantle represented by YSGO suiteforming in early Paleozoic in the North Qilian Moutains is very similar to the Tethyan mantle inboth trace elements and isotopic compositions. The North Qilian Mountains should be a part of theTethyan tectonic domain in early Paleozoic. This further implies that the Tethyan tectonic domaincan be deduced to early Paleozoic in the study area, which will be helpful to discussing thetectonic affinity and evolution of the North Qilian Mountains.

关键词： geochemistry, Indian Ocean-MORB-type isotopic signatures, Tethyan tectonic domain, Yushigou ophiolite, North Qilian Mountains.

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Application of output feedback sliding mode control to active flutter suppression of two-dimensional airfoil

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Science China(Technological Sciences) 2010年第5期53卷 1338-1348页

作者： YANG Chao,SONG Chen,WU ZhiGang & XIE ChangChuan school of Aeronautic Science and Engineering,beijing university of Aeronautics & Astronautics,{3.,China 1. school of Aeronautic Science and Engineering Beijing University of Aeronautics & Astronautics Beijing 100191 China

The effectiveness of the sliding mode control(SMC) method for active flutter suppression(AFS) and the issues concerning control system discretization and control input constraints were studied using a typical two-dimensional *** airfoil has a trailing-edge flap for flutter *** aeroelastic system involves a two-degrees-of-freedom motion(pitch and plunge),and the equations were constructed by utilizing quasi-steady aerodynamic *** control system,designed by the output feedback SMC method,was incorporated to suppress the pitch-plunge ***,the system discretization and the flap deflection constraints were ***,a classical Runge-Kutta(RK) algorithm was utilized for numerical *** results indicated that the close-loop system with the SMC system could be stable at a speed above the flutter ***,when the flap deflection limits are reached,the close-loop system with the simple discretized control system loses ***,control compensation developed by theoretical analysis was proposed to make the system stable *** parameter perturbations and the time delay effects were also discussed in this paper.

关键词： aeroelasticity flutter airfoil sliding mode control output feedback control

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