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Constructions of Some Exact VortexSuperposition Solutions

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Communications in Nonlinear science and Numerical Simulation 1999年第4期4卷 3-5页

作者： Xin HU Yonghan HUANG(department of Mechanics and Engineering science, state Key Laboratory for TurbulenceResearch, Peking university, Beijing 100871, China) department of Mechanics and Engineering science State Key Laboratory for Turbulence Research Peking University Beijing 100871 China

IntroductionOneofthemostusefulmethodstosolvetheN-Sequationistodecomposethevelocity（l）(z)where.（'）--acNow,***3=w3（t）,wewillthengetco3=coear(jb（t）dt).Ifwetakeg=--M（axl+fixs）+ac,T=--M（Axf+Bx;）+cohere,goandcos... 详细信息

关键词： exact solution Stokes-Helmholtz decomposition vorticity equation

Eigenvalue approximation from below using non-conforming finite elements

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science China Mathematics 2010年第1期53卷 137-150页

作者： YANG YiDu 1 ,ZHANG ZhiMin 2 & LIN FuBiao 11 School of Mathematics and Computer science,Guizhou Normal university,Guiyang 550001,China 2 department of Mathematics,Wayne state university,Detroit,MI 4.202,usa 1. School of Mathematics and Computer science Guizhou Normal University Guiyang 550001 China2. Department of Mathematics Wayne State University Detroit MI 48202 USA

This is a survey article about using non-conforming finite elements in solving eigenvalue problems of elliptic operators,with emphasis on obtaining lower bounds. In addition,this article also contains some new materials for eigenvalue approximations of the Laplace operator,which include:1) the proof of the fact that the non-conforming Crouzeix-Raviart element approximates eigenvalues associated with smooth eigenfunctions from below;2) the proof of the fact that the non-conforming EQ rot1 element approximates eigenvalues from below on polygonal domains that can be decomposed into rectangular elements;3) the explanation of the phenomena that numerical eigenvalues λ 1,h and λ 3,h of the non-conforming Q rot1 element approximate the true eigenvalues from below for the L-shaped domain. Finally,we list several unsolved problems.

关键词： non-conforming element eigenvalue lower bound

A Spectral Index for Estimating Soil Salinity in the Yellow River Delta Region of China Using EO-1 Hyperion Data

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Pedosphere 2010年第3期20卷 378-388页

作者： WENG Yong-Ling GONG Peng ZHU Zhi-Liang department of Surveying and Mapping Engineering College of Transportation Southeast University Nanjing 210096(China) state Key Laboratory of Remote Sensing science Institute of Remote Sensing Applications of the Chinese Academy ofSciences and Beijing Normal University Beijing 100101 (China) department of Environment science Policy and Management University of California Berkeley CA 94720 (USA) EROS Data Center U.S. Geological Survey Sioux Falls SD 57198 (USA)

Soil salinization is one of the most common land degradation processes. In this study, spectral measurements of saline soil samples collected from the Yellow River Delta region of China were conducted in laboratory and hyperspectral data were acquired from an EO-1 Hyperion sensor to quantitatively map soil salinity in the region. A soil salinity spectral index (SSI) was constructed from continuum-removed reflectance (CR-reflectance) at 2052 and 2203 nm, to analyze the spectral absorption features of the salt-affected soils. There existed a strong correlation (r = 0.91) between the SSI and soil salt content (SSC). Then, a model for estimation of SSC with SSI was established using univariate regression and validation of the model yielded a root mean square error (RMSE) of 0.986 and an R2 of 0.873. The model was applied to a Hyperion reflectance image on a pixel-by-pixel basis and the resulting quantitative salinity map was validated successfully with RMSE = 1.921 and R2 = 0.627. These suggested that the satellite hyperspectral data had the potential for predicting SSC in a large area.

关键词： hyperspectral reflectance soil salt content spectral absorption features

Carbon isotope composition of the Lower Triassic marine carbonates, Lower Yangtze Region, South China

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science China Earth sciences 2006年第3期49卷 225-241页

作者： ZUO Jingxun1,2, TONG Jinnan3, QIU Haiou4.& ZHAO Laishi3 1. Nanjing Institute of Geology and Palaeontology, Chinese Academy of sciences, Nanjing 210008, China 2. Henan Institute of geological Survey, Zhengzhou 4.0007, China 3. state Key Laboratory of geological Processes and Mineral Resources at China {4. of Geosciences, Wuhan 4.0074. China 4. Faculty of Material sciences and Chemical Engineering, China {4. of Geosciences, Wuhan 4.0074. China 1. Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China 2. Henan Institute of geological Survey Zhengzhou 450007 China 3. state Key Laboratory of geological Processes and Mineral Resources at China university of Geosciences Wuhan 430074 China 4. Faculty of Material sciences and Chemical Engineering China University of Geosciences Wuhan 430074 China

Studies on three Lower Triassic sections located on the shallow water platform, the deep water slope and in the deep water basin in the Lower Yangtze Region, South China, show the similar trend of carbon isotope evolution. Biostratigraphic correlations among the Lower Triassic sections on the basis of standard conodont zones indicate that three negative shifts occurred in the Griesbachian, the Smithian and the late Spathian stages respectively, and one distinctly positive shift occurred in the early Spathian stage. Trend of carbon isotope evolution of the Lower Triassic reflects some significant changes in the global carbon cycle. Moreover, δ 13C background values are intensively controlled by palaeogeographic environment. In general, δ 13C values from deep-water slope carbonates are lighter than those from carbonate platform and heavier than those from deep-water basin carbonates. The positive carbon isotope excursion may be induced by a significant amount of organic carbon burial in marine sediments and increase in primary productivity. The large negative carbon isotope excursions during the Early Triassic in Lower Yangtze Region are interpreted to relate to volcano eruptions based on tuffaceous claystone interlayers observed near the Permian-Triassic boundary, the Induan- Olenekian boundary and the Lower Triassic-Middle Triassic boundary.

关键词： Lower Triassic, carbon isotope compositions, palaeogeography, volcanic eruptions, Lower Yangtze Region.

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 Academy of sciences, Beijing 100101, China 2. Research Center for Remote Sensing and GIS, department of Geography, Beijing Normal {4., Beijing 100875, China 3. Graduate {4. of Chinese Academy of sciences, Beijing 100039, China 4. department of Atmospheric Physics, Peking {4., Beijing 100871, China 1. state Key Laboratory of Remote Sensing science Institute of Remote Sensing Applications Chinese Academy of Sciences 100101 Beijing China2. Research Center for Remote Sensing and GIS Department of Geography Beijing Normal University 100875 Beijing China3. Graduate University of Chinese Academy of Sciences 100039 Beijing China4. Department of Atmospheric Physics Peking University 100871 Beijing 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 2004. 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.

Monitoring of rice crop using ENVISAT ASAR data

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science China Earth sciences 2006年第7期49卷 755-763页

作者： DONG Yanfang1, 2, SUN Guoqing1,3 & PANG Yong4.1. state Key Laboratory of Remote Sensing science, Institute of Remote Sensing Applications, Chinese Academy of sciences, Beijing 100101, China 2. Graduate university of Chinese Academy of sciences, Beijing 100039, China 3. department of Geography, university of Maryland, College Park, MD 2074., usa 4. Forest Remote Sensing Lab, Research Institute of Forest Resource and Information Technology, Chinese Academy of For-estry, Beijing 100091, China 1. state Key Laboratory of Remote Sensing science Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing 100101 China 2. Graduate university of Chinese Academy of sciences Beijing 100039 China 3. department of Geography University of Maryland College Park MD 20742 USA 4. Forest Remote Sensing Lab Research Institute of Forest Resource and Information Technology Chinese Academy of Forestry Beijing 100091 China

Because of the cloudy conditions during the rice growth period, rice is one of the agri-cultural crops most suited to monitoring with the SAR instruments. Backscatter response measured by SAR is correlated with rice conditions, including height, density, biomass and structure, which are variable at different growing stages. In this paper, multi-date ENVISAT ASAR Alternating Polarization Mode (APMode) imageries were acquired during the rice crop growing cycle. At the same time, the rice parameters were measured in field. A continuous canopy model was used to compute the back-scattering from rice fields during the growth cycle, and the relationship between rice parameters and radar backscattering coefficients from both ASAR and modeling was analyzed. The effects of polari-zation, incidence angle and polarization on radar backscattering coefficients were analyzed. It was found that simulated radar backscatter has similar trends as ASAR data. This will be meaningful for the further research of rice parameters estimation from ASAR data. Different features show signifi-cantly different signatures in ASAR images and they follow some certain laws, so rice area can be accurately mapped by using multi-temporal SAR images, then rice yield can be estimated.

关键词： rice, ASAR, radar backscattering, model.

Geochemistry of high-Mg andesites from the early Cretaceous Yixian Formation, western Liaoning: Implications for lower crustal delamination and Sr/Y variations

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science China Earth sciences 2006年第9期49卷 904-914页

作者： WANG Xiaorui1, GAO Shan1,2, LIU Xiaoming1, YUAN Honglin1, HU Zhaochu1, ZHANG Hong1,3 & WANG Xuance4.1. state Key Laboratory of Continental Dynamics, department of Geology, Northwest university, Xi`an 710069, China 2. state Key Laboratory of {4. Processes and Mineral Resources, China university of Geosciences, Wuhan 4.0074. China 3. Shenyang Institute of Geology and Mineral Resources, Shenyang 110032, China 4. Guangzhou Institute of Geochemistry, Chinese Academy of sciences, Guangzhou 51064., China 1. state Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi’an 710069 China 2. state Key Laboratory of geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China 3. Shenyang Institute of Geology and Mineral Resources Shenyang 110032 China 4. Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China

85 volcanic rocks of the Yixian Formation from the Sihetun type section werecollected and analyzed for geochemical and isotopic compositions. Major element compositionsindicate that the Sihetun volcanic rocks are high magnesium andesites with some basalts occurring atthe bottom of section. The Sihetun high magnesium andesites (SiO_2 = 52.82-59.31 wt%, Al_2O_3=14.15-16.35wt%) show many characteristics of adakites such as depletion in heavy rare-earth elements(HREE; Yb = 1.03-1.88 μg/g) and Y(12-20 μg/g) and high Sr (620-1323 μg/g) and Sr/Y(32-88), withhigh La_N/Yb_N ratio (10-25). They share similar major and trace element characteristics to volcanicrocks from the Xinglonggou Formation except their lower Nd isotope ratios (^(14.)Nd/^(14.)Nd(130Ma) = 0.5118-0.5119, ε_(Nd) (130Ma) = -11.6-13.8, ^(87)Sr/^(86)Sr (130 Ma) = *** were interpreted in a way that eclogite that formed at the base of thickened Archean lowercrust of the North China craton foundered into the convecting mantle and subsequently melted andinteracted with peridotite. However, compared to the Xinglonggou volcanic rocks, the source of theSihetun magma contained more ancient continental crustal material in order to explain its evolved Ndisotopes. The age of the Sihetun Formation was 120 to 130 Ma, and this indicates that delaminationlasted to the early Cretaceous period. The Sr contents and Sr/Y ratios of the Sihetun high-Mgandesites show significant negative correlations with SiO_2 for samples with SiO_2 > 56%. Thesesuggest that the Sr and Sr/Y values were reduced due to fractional crystallization of ***, the effect of crystallization on volcanic Sr and Sr/Y ratio has to be taken intoaccount.

关键词： High-Mg andesite, Adakite, Yixian Formation, North China Craton, delamination.

One Kind of nth Beltrami Spherical VortexTensor Denotation and its Classification

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Communications in Nonlinear science and Numerical Simulation 1999年第4期4卷 3-5页

作者： Yongnian HUANG Xin HU(department of Mechanics and Engineering science & state Key Laboratory forTurbulence Research, Peking university, Beliing 100871, China) department of Mechanics and Engineering science & state Key Laboratory for Turbulence Research Peking University Beijing 100871 China

1OneKindofnibBSVTensorDenotationInaxticle[1],wehadgiventhesolutionsofthebosymmetricnibBeltramiSphericalVortex(BSV)asfollows:Inarticle[21,wegavethegeneralformofthenibBSV(expressedbythetensordenotation)couldbewrittenas:... 详细信息

关键词： spherical vortex tensor denotation symmetry

Large second-order optical nonlinearities of s-triazine derivatives: View from micro molecules to macro crystals

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science China Chemistry 2005年第3期48卷 203-209页

作者： FANG Qi1, LEI Hong2, CUI Yuezhi3, HUANG Zhenli4. XUE Gang1 & YU Wentao1 1. state Key Laboratory of Crystal Materials, Shandong university, Jinan 250100, China 2. School of Information science and Engineering, Shandong university, Jinan 250100, China 3. {4. of Chemical Engineering, Light Industry College of Shandong, Jinan 250100, China 4. Key Laboratory of Biomedical Photonics, Ministry of Education, Huazhong university of science and Technology, Wuhan 4.0074. China 1. state Key Laboratory of Crystal Materials Shandong University 250100 Jinan China 2. School of Information science and Engineering Shandong University 250100 Jinan China 3. department of Chemical Engineering Light Industry College of Shandong 250100 Jinan China 4. Key Laboratory of Biomedical Photonics Ministry of Education Huazhong University of Science and Technology 430074 Wuhan China

Three s-triazine derivatives have been synthesized and their structures been de-termined. These are Compound I: 2,4.dimethyl-6-(p-N,N-dimethylaminostyryl)-s-triazine (abbre-viated to NMe-1), Compound II: 2,4.dimethyl-6-(p-N,N-diethylaminostyryl)-s-triazine (to NEt-1), and Compound III: 2-methyl-4.6-bis(p-N,N-dimethylaminostyryl)-s-triazine (NMe-2). NMe-1 and NEt-1 molecules belong to the D-π-A type with a one-dimensional charge-transfer character. NMe-1 crystallizes to centrosymmetric P1 space group, while NEt-1 to non-centrosymmetric polar Cc space group with all of the molecular charge-transfer axes taking the same orientation. Under the irradiation of 1064.nm fundamental laser, NEt-1 powder crystals radiate a 2-order harmonic light with an intensity 4..8 times that of urea. The Λ typed NMe-2 molecule, which has a two-dimensional charge-transfer character, crystallizes to polar P21 space group. Its powder crystals exhibit a 2-order harmonic intensity 4..2 times that of urea. The quantum chemical cal-culations and tensor analyses have been carried out to reveal the dependence of the macro 2-order nonlinear optical (NLO) efficiency on the micro 2-order NLO coefficients (β) and on the crystalline packing styles.

关键词： s-triazine derivatives, synthesis, structure, SHG intensities of crystals, βvalues of molecules.