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Experimental measurement of growth patterns on fossil corals:Secular variation in ancient Earth-Sun distances

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Chinese science Bulletin 2010年第35期55卷 4010-4017页

作者： ZHANG WeiJia1,3,4,LI ZhengBin2,3 & LEI Yang1 1 Department of Physics,peking university,beijing 100871,china 2 Department of Electrical Engineering and Computer science,peking university,beijing 100871,china 3 State Key Laboratory of Advanced Optical Communication Systems & Networks,peking university,beijing 100871,china 4 Committee of Yuanpei Honors Program,peking university,beijing 100871,china Department of Physics Peking University Beijing 100871 China State Key Laboratory of Advanced Optical Communication Systems & Networks Peking University Beijing 100871 China Committee of Yuanpei Honors Program Peking University Beijing 100871 China Department of Electrical Engineering and Computer science Peking University Beijing 100871 China

In recent years,much attention has been given to the increase in the Earth-Sun distance,with the modern rate reported as 5-15 m/cy on the basis of astronomical ***,traditional methods cannot measure the ancient leaving rates,so a myriad of research attempting to provide explanations were met with unmatched *** this paper we consider that the growth patterns on fossils could reflect the ancient Earth-Sun *** mechanical analysis of both the Earth-Sun and Earth-Moon systems,these patterns confirmed an increase in the Earth-Sun *** a large number of well-preserved specimens and new technology available,both the modern and ancient leaving rates could be measured with high precision,and it was found that the Earth has been leaving the Sun over the past 0.53 billion *** Earth's semi-major axis was 146 million kilometers at the beginning of the Phanerozoic Eon,equating to 97.6% of its current *** modern leaving rates are 5-14 m/cy,whereas the ancient rates were much *** results indicate a special expansion with an average expansion coefficient of 0.57H0 and deceleration in the form of Hubble *** the basis of experimental results,the Earth's semi-major axis could be represented by a simple formula that matches fossil measurements.

关键词：地球太阳古代距离生长模式实验石珊瑚量化

Unsteady aerodynamic modeling based on POD-observer method

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science china(Technological sciences) 2010年第8期53卷 2032-2037页

作者： YANG Chao,LIU XiaoYan &WU ZhiGang beijing university of Aeronautics and Astronautics,beijing 100191,china 1. beijing university of Aeronautics and Astronautics Beijing 100191 China

A new hybrid approach to constructing reduced-order models(ROM)of unsteady aerodynamics applicable to aeroelastic analysis is presented by using proper orthogonal decomposition(POD)in combination with observer *** modes are generated through POD by sampling observations of solutions derived from the full-order *** response in the POD training is projected onto the fluid modes to determine the time history of the modal *** resulting data are used to extract the Markov parameters of the low-dimensional model for modal amplitudes using a related deadbeat *** state-space realization is synthesized from the system's Markov parameters that are processed with the eigensystem realization *** POD-observer method is applied to a two-dimensional airfoil system in subsonic flow *** results predicted by the ROM are in general agreement with those from the full-order *** ROM obtained by the hybrid approach captures the essence of a fluid system and produces vast reduction in both degrees of freedom and computational time relative to the full-order model.

关键词： aeroelasticity aerodynamic modeling proper orthogonal decomposition observer eigensystem realization algorithm

BRILL-NOETHER MATRIX FOR RANK TWO VECTOR BUNDLES

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Chinese Annals of Mathematics,Series B 2002年第4期23卷 531-538页

作者： TAN XIAOJIANGSchool of Mathematical sciences, peking university, beijing 100871, china School of Mathematical sciences Peking University Beijing 100871 China

Let X be an arbitrary smooth irreducible complex projective curve, E (?)X a rank two vector bundle generated by its sections. The author first represents ?as a triple {D1,D2,f}, where D1 , D2 are two effective divisors with d = deg(D1) + deg(D2), and f ∈ H?X, [D1] |D2) is a. collection of polynomials. E is the extension of [D2] by [D1] which is determined by f. By using / and the Brill-Noether matrix of D1+D2, the author constructs a 2g × d matrix WE whose zero space gives Im{H0(X,[D1]) (?) H0(X, [D1] |D1)}(?) Im{H?X, E) (?) H0(X,[D2]) (?) H0(X, [D2]|D2)} From this and H0(X,E) = H0(X,[D1]) (?)Im{H0(X,E) (?) H0(X, [D2])}, it is got in particular that dimH0(X, E) = deg(E) - rank(WE) + 2.

关键词： Brill-Noether matrix Vector bundle Effective divisor

Electrical Properties of Expanded Graphite Intercalation Compounds

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Journal of Materials science & Technology 2001年第3期17卷 371-374页

作者： Xiuyun CHUAN Department of Geology, peking university, beijing 100871, china Daizhang CHEN and Xunruo ZHOU Department of Materials science, china university of Geosciences, beijing 100083, china E-mail: cxyljhcj@*** peking Univ Dept Geol Beijing 100871 Peoples R China china Univ Geosci Dept Mat Sci Beijing 100083 Peoples R China

The intercalation compounds of CuCl2 were synthesized with expanded graphite, whose magnitude of the electrical conductivity is about 10(3)S(.)cm(-1). Their electrical conductivity is 3 similar to6 times as high as that of the expanded graphite, and about 10 times as high as that of GIC made of the non-expanded graphite. The microanalysis results of chemical compounds by X-ray energy spectrum scanning of TEM testified that the atomic ratio of chloride and cupric is nonstoichoimetric. The multivalence and exchange of electrovalence of the cupric ion was confirmed by the XPS-ESCA. Vacancy of chlorine anion increases the concentration of charge carrier. The special stage structure, made of graphite and chloride, produces a weak chemical bond belt and provides a carrier space in the direction of GIC layer. These factors develop the electrical properties.

关键词： In Ph Electrical Properties of Expanded Graphite Intercalation Compounds Graphite ESCA

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 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 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

Theoretical analysis of alloy multiplying factor by the empirical electron theory of solids and molecules

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science china(Technological sciences) 2007年第6期50卷 807-814页

作者： SONG YuePeng1,2, LIU GuoQuan2, LI ZhiLin3, FENG ChengMing1 1 Mechanical and Electronic Engineering College, Shandong Agricultural university, Tai’an 271018, china 2 College of Materials science and Engineering, university of science and Technology, beijing 100083, china 3 College of Material science and Engineering, beijing university of Chemical Technology, beijing 100029, china Mechanical Electronic Engineering College Shandong Agricultural University Tai’an 271018 China College of Materials science Engineering University of Science Technology Beijing 100083 China College of Material science Engineering Beijing University of Chemical Technology Beijing 100029 China

By introducing the distribution probability of structural units in austenite contain- ing alloying elements and considering its effects on phase transformation, this paper establishes a calculation model of distribution probability of structural units. A new valence electron structure (VES) parameter-transformation effect coefficient of alloying elements (HL), is defined and then studied both theoretically and ex- perimentally. The relationship between the parameter HL and the multiplying factor (the quenching capability factor) of alloying elements is studied. The results indi- cate that the two parameters (HL and the quenching capability factor) have the same variation characteristic and substance feature. Therefore, the multiplying factor virtually expresses the relative quantity of structural units in the alloying elements-containing austenite.

关键词： multiplying factor (the quenching capability factor), empirical electron theory of solids and molecules, transformation effect coefficient of alloying elements, structural units in austenite containing alloying elements

Implications of micro-compositions of garnet and biotite from high-grade meta-pelites

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Progress in Natural science:Materials International 2006年第2期16卷 209-214页

作者： ZHOU Xiwen, WEI Chunjing, and ZHANG Shangkun ( institute of Geology, CAGS, beijing 100037, china School of Earth and Space sciences, peking university, beijing 100871, china china university of Geo-sciences, beijing 100083, china) institute of Geology CAGS Beijing 100037 China School of Earth and Space sciences Peking University Beijing 100871 China china university of Geo-sciences Beijing 100083 China

Based on detailed studies on the compositional zoning of garnet and biotite in pelitic rocks from the Jingshan group of granulite facies in north Jiaodong, P-T pseudosections with isopleths of Fe/(Fe + Mg) in garnet and biotite were calculated in the KF-MASH system for two representative rocks of sillimanite-garnet-cordierite-biotite gneiss ( Vbi/ Vg>1 ) and sillimanite-garnet gneiss (Vbi/ Vg2) using the software THERMOCALC and the internally consistent thermodynamic dataset. With a comparison of the calculated Fe/(Fe+ Mg) values in garnet and biotite in the peak P-T fields constrained by peak mineral assemblages with the measured ones, it is concluded that the coarse garnet crystals with diffusion zoning from high grade meta-pelites can preserve their peak compositions even when they have experienced a cooling event, and that biotite crystals surrounded by fetsic minerals in biotite-rich rocks with Vbi/Vg> 1 can nearly preserve their peak compositions, and biotites in garnet-rich rocks with Vbi/Vg2 cannot preserve their peak compositions due to the influence of grain-boundary fluid.

关键词： high-grade meta-pelites THERMOCALC P-T pseudosection peak compositions of garnet and biotite.

Categories and characteristics of urban villages by GIS-based analysis:A case study of the Shenzhen Special Economic Zone

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science china(Technological sciences) 2010年第S1期53卷 150-157页

作者： TONG De1,FENG ChangChun2,LI GuiCai1 & CHEN Peng1,2 1S henzhen Graduate School,peking university,Shenzhen 518055,china 2College of Urban and Environmental science,peking university,beijing 100871,china 1. Shenzhen Graduate School Peking University Shenzhen 518055 China 2. College of Urban and Environmental science Peking University Beijing 100871 China

Studies on the characteristics of urban villages have attracted much interest in urban ***,how to advance the development of further theoretical analysis and quantitative methodologies,especially in the era that GIS and digital-urban technologies develop rapidly and provide precious resources on spatial issues,has always been a heated debate and *** this paper,a mathematical model based on spatial analysis is introduced to deal with the categorization and characterization of urban villages.A total of 89 urban villages in the Shenzhen Special Economic Zone(SEZ)are used in this case *** ArcGIS tools on buffer analysis,distance and density calculation,and socio-economic and spatial attributes conjunction,urban villages’31 spatial variables in 4 aspects—social,economic,locational,and physical—are extracted,and 6 principal factors are concluded by principal components analysis to indicate the spatial characteristic of urban *** on the 6 principal factors,6 types of urban villages,including rapidly sprawling,large,rapidly industrializing periphery,overcrowded,intensively mobile and economically backward,are divided through the Hierarchical Clustering ***,the spatial features and formation mechanisms of each type of urban villages are ***,the advantages and the shortcomings of the methodology for this specific application are also ***,several guidelines on urban village management and renewal are provided based on the result of type *** outcome of the paper depends on the informational and technological support from the development of digital-city management,and is able to in turn provide basis on monitoring and improving urban villages which can further digital urban framework.

关键词： urban villages GIS-based analysis principal component hierarchical cluster the Shenzhen Special Economic Zone (SEZ)

Effects of heat treatment on magnetic properties of Co-Fe-plated hollow ceramic microspheres

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Progress in Natural science:Materials International 2011年第5期21卷 392-400页

作者： Xiang LI,Yue-xin DUAN,Yan ZHAO,Lei ZHU School of Materials science and Engineering,beijing university of Aeronautics and Astronautics, beijing 100191,china School of Materials science and Engineering Beijing University of Aeronautics and Astronautics Beijing 100191 China

Functional hollow ceramic microspheres plated with Co-Fe were obtained through electroless plating technique for the application of lightweight microwave *** were treated at different temperatures by vacuum annealing *** surface-coated hollow microspheres were characterized by scanning electron microscopy(SEM) and X-ray diffraction analysis (XRD).The microwave electromagnetic loss and absorbing properties of hollow microspheres plated with Co-Fe were tested by network vector *** magnetic properties were tested by vibrating sample magnetometer(VSM).The results show that the annealing treatment changed the crystal phase of Co from HCP to FCC,simultaneously increased the crystallinity and crystal size of Co and Fe in coating ***,after annealing at 800℃or 1 000℃,the microwave absorbing properties and soft magnetic properties of hollow microspheres plated with Co-Fe were further improved.

关键词： electroless plating hollow ceramic microspheres magnetic properties heat treatment Co-Fe