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CONVERGENCE AND SUPERCONVERGENCE OF heRMITE BICUBIC ELEMENT FOR EIGENVALUE PROBLEM OF The BIHARMONIC EQUATION

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Journal of Computational Mathematics 2001年第2期19卷 139-142页

作者： Dong-sheng Wu (institute of Systems Science, academy of Mathematics and Systems sciences, chinese academy of sciences, Beijing 100080, China ) 中科院系统科学所北京 100080

Provides information on a study which discussed the convergence and superconvergence for eigenvalue problem of the biharmonic equation using the hermite bicubic element. Discussion on eigenvalue problem for biharmonic equation; Background on asymptotic error expansions and interpolation postprocessing; Superconvergence approximations to the eigenvalue and eigenfunction.

关键词： hermite bicubic element biharmonic equation interpolation postprocessing eigenvalue problem

Effect of water stress on ecosystem photosynthesis and respiration of a Leymus chinensis steppe in Inner Mongolia

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Science China Earth sciences 2006年第S2期49卷 196-206页

作者： FU yuling , yu Guirui , WANG Yanfen, LI Zhengquan & HAO Yanbin institute of Geographic sciences and Natural Resources Research, chinese academy of sciences, Beijing 100101, China The Graduate University of chinese academy of sciences, Beijing 100049, China institute of Botany, chinese academy of sciences, Beijing 100093, China institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing China The Graduate University of chinese academy of sciences Beijing China institute of Botany Chinese Academy of Sciences Beijing China

Many studies on global climate have forecast major changes in the amounts and spatial patterns of precipitation that may significantly affect temperate grasslands in arid and semi-arid regions. As a part of ChinaFLUX, eddy covariance flux measurements were made at a semi-arid Leymus chinensis steppe in Inner Mongolia, China during 2003-2004 to quantify the response of carbon exchange to environmental changes. Results showed that gross ecosystem production (FGEP) and ecosystem respiration (Reco) of the steppe were significantly depressed by water stress due to lack of precipitation during the growing season. Temperature was the dominant factor affecting FGEP and Reco in 2003, whereas soil moisture imposed a significant influence on both Reco and FGEP in 2004. Under wet conditions, Reco showed an exponentially increasing trend with temperature (Q10 = 2.0), but an apparent reduction in the value of Reco and its temperature sensitivity were observed during the periods of water stress (Q10=1.6). Both heat and water stress can cause decrease in FGEP. The sea-sonality of ecosystem carbon exchange was strongly correlated with the variation of precipitation. With less precipitation in 2003, the steppe sequestrated carbon in June and July, and went into a senescence in early August due to water stress. As compared to 2003, the severe drought during the spring of 2004 delayed the growth of the steppe until late June, and the steppe became a CO2 sink from early July until mid-September, with ample precipitation in August. The semi-arid steppe released a total of 9.7 g C·m-2 from May 16 to the end of September 2003, whereas the net carbon budget during the same period in 2004 was close to zero. Long-term measurements over various grasslands are needed to quantify carbon balance in temperate grasslands.

关键词： Leymus chinensis steppe water stress ecosystem respiration gross ecosystem production net ecosystem CO2 exchange.

PREPARATION AND PROPERTIES OF ETHYL-CYANOETHYL CELLULOSE/POLYACRYLIC ACID COMPOSITE FILMS WITH REFLECTION COLORS

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chinese Journal of Polymer Science 2001年第3期19卷 277-282页

作者： Yong Huang institute of Chemistry, chinese academy of sciences, Beijing 100080 China Laboratory of Cellulose and Lignocellulosics Chemistry Guangzhou institute of Chemistry chinese academy of sciences, Guangzhou 510650, China 中科院化学所北京

Ethyl-cyanoethyl cellulose [(E-CE)C]/acrylic acid (AA) becomes a cholesteric liquid crystalline solution withvivid colors when the (E-CE)C concentration is 42 wt%～52 wt%. (E-CE)C/polyacrylic acid (PAA) composites withcholesteric structure were prepared by polymerzing AA in (E-CE)C/AA liquid crystalline solutions. The layers of orderedpolymer chains in the cholesteric phase were inclined during polymerization and the degree of the inclination depended onthe polymerization temperature and the concentration of the solution before polymerization. The cholesteric structure in thecomposites could not be changed when temperature was lower than 100℃. Cross-linking of the PAA in compositesimproved their water-resistance. The cholesteric order of the composites without cross-linking was destroyed when theywhere immersed in water. The color derived from the selective reflection of the cholesteric phase of the cross-linkedcomposites turned from blue to red after the composites absorbed water. The color of the composites could be returned to theoriginal one when the absorbed water was removed from the swollen composites.

关键词： Cholesteric structure Composites Selective reflection Liquid crystalline solutions

The relationship between MRP1 activities and its NBD conformational changes

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Science China(Life sciences) 2004年第5期47卷 425-433页

作者： HUANG Zhenhua & HUANG Youguo National Laboratory of Biomacromolecules, Center for Structural and Molecular Biology, institute of biophysics, chinese academy of sciences, Beijing 100101, China National Laboratory of Biomacromolecules Center for Structural and Molecular Biology Institute of Biophysics Chinese Academy of Sciences Beijing China

MIANS, a sulfhydryl-reactive fluorescence, was used to label the cysteines of MRP1 (multidrug resistance protein), and the results indicated that an increase in fluorescence intensity and a large emission blue shift took place after two Cys residues of MRP1 reacted with MIANS, which demonstrated that labeled Cys residues in MRP1 reside in a relatively hydrophobic envi-ronment. The experimental results obtained from fluorescence resonance energy transfer further uncover that two Cys residues of MRP1 modified by MIANS located in the vicinity of its NBDs, of which one lies close to NBD1, and the other near NBD2. ATP, ADP and anticancer drugs can all reduce the rate of reaction of MRP1 with MIANS. The collisional quenchers, acrylamide, I-, and Cs+ were used to assess local environments of MIANS bound to MRP1 and the results showed that the region around the MIANS-labeled cysteine is positively charged. Both MIANS and NEM, which are sulfhydryl-reactive reagents, inhibited MRP1 ATPase activity, whereas anticancer drugs activated it. These results demonstrated that all nucleotides and drugs could induce changes in conformation of the NBDs in MRP1. Nucleotides can bind directly to NBDs, but drugs may react first with TMDs, which in turn alters the accessibility of the two Cys residues bound by MIANS and affects MRP1 ATPase activity, which is coupled with the transport of its substrates. Taken together, the above experimental results provide direct evidence for further study on the coupling of translocation of the transported species to hydrolysis of ATP in MRP1.

关键词： MRP1,multidrug resistance,conformation,coupling.

Cloning and Analyzing of Xenopus Mespo Promoter in Retinoic Acid Regulated Mespo Expression

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Acta Biochimica et Biophysica Sinica 2006年第11期38卷 759-764页

作者： Jin-Hu WANG Xiao-Yan DING* institute of Biochemistry and Cell Biology,Shanghai institutes for Biological sciences,chinese academy of sciences,Graduate School of the chinese academy of sciences,Shanghai 200031,China institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Graduate School of the Chinese Academy of SciencesShanghai 200031 China

During vertebrate embryogenesis,presomitic mesoderm cells enter a segmental program togenerate somite,a process termed ***,a member of the bHLH transcription factor family,plays important roles in this ***,how Mespo expression is regulated remains *** this question,we isolated a genomic DNA sequence containing 4317 bp of Mespo 5’ flanking regionin *** assays show that this upstream sequence has transcription *** assayshows that this genomic contig is sufficient to recapitulate the dynamic stage-and tissue-specific expressionpattern of endogenous Mespo from the gastrula to the tailbud *** further mapped a 326 bp DNAsequence responding to retinoic acid *** results shed light on how Mespo expression is regulated,and suggest that retinoic acid signaling pathways play roles in somitogenesis through regulating Mespo.

关键词： bHLH paraxial presomitic segmental tailbud Xenopus laevis

Transformations and non-degenerate maps

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Science China Mathematics 2005年第Z1期48卷 195-205页

作者： LI Baokui & WANG yuefei institute of Mathematics, academy of Mathematics and System sciences, chinese academy of sciences, Beijing 100080, China Graduate School, chinese academy of sciences, Beijing 100080, China institute of Mathematics Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing China Graduate School Chinese Academy of Sciences Beijing China

We shall prove the equivalences of a non-degenerate circle-preserving map and a M(o)bius transformation in ^Rn, of a non-degenerate geodesic-preserving map and an isometry in Hn of a non-degenerate line-preserving map and an affine transformation in Rn. That a map is non-degenerate means that the image of the whole space under the map is not a circle, or geodesic or line respectively. These results hold without either injective or surjective, or even continuous assumptions, which are new and of a fundamental nature in geometry.

关键词： M(o)bius transformation, circle-preserving map, non-degenerate map.

XPS Study on Water-Soluble Polymer Surfactant Film

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chinese Chemical Letters 1997年第12期8卷 0-0页

作者： Jian XU Liang he shi Mei Ling YE (Polymer Physics Laboratory, institute of Chemistry, chinese academy of sciences, Beijing 100080) Chemistry Department Fudan University Shanghai 200433 China

By means of changing the detection angle, the molecular conformation of a new type of polymer surfactant, acrylamide-poly(oxyethykene alkyl ether)acrylate-anionic monomer random copolymer, was studied by x-ray photoel... 详细信息

关键词： XPS Study on Water-Soluble Polymer Surfactant Film

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Seasonal and annual variation of CO_2 flux above a broad-leaved Korean pine mixed forest

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Science China Earth sciences 2006年第S2期49卷 63-73页

作者： ZHANG Junhui, yu Guirui, HAN shijie, GUAN Dexin & SUN Xiaomin institute of Applied Ecology, chinese academy of sciences, Shenyang 110016, China institute of Geographic sciences and Natural Resources Research, chinese academy of sciences, Beijing 100101, China institute of Applied Ecology Chinese Academy of Sciences Shenyang China institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing China

Long-term measurement of carbon metabolism of old-growth forests is critical to predict their behaviors and to reduce the uncertainties of carbon accounting under changing climate. Eddy covariance technology was applied to investigate the long-term carbon exchange over a 200 year-old chinese broad-leaved Korean pine mixed forest in the Changbai Mountains (128°28’E and 42°24’N, Jilin Province, P. R. China) since August 2002. On the data obtained with open-path eddy covariance system and CO2 profile measurement system from Jan. 2003 to Dec. 2004, this paper reports (i) annual and seasonal variation of FNEE, FGPP and Re; (ii) regulation of environmental factors on phase and amplitude of ecosystem CO2 uptake and release Corrections due to storage and friction velocity were applied to the eddy carbon flux. Lal and soil temperature determined the seasonal and annual dynamics of FGPP and RE separately. VPD and air temperature regulated ecosystem photosynthesis at finer scales in growing seasons. Water condition at the root zone exerted a significant influence on ecosystem maintenance carbon metabolism of this forest in winter. The forest was a net sink of atmospheric CO2 and sequestered -449 g C·m-2 during the study period; -278 and -171 gC·m-2 for 2003 and 2004 respectively. FGPP and FRE over 2003 and 2004 were -1332, -1294 g C·m-2. and 1054, 1124 g C·m-2 respectively. This study shows that old-growth forest can be a strong net carbon sink of atmospheric CO2. There was significant seasonal and annual variation in carbon metabolism. In winter, there was weak photosynthesis while the ecosystem emitted CO2. Carbon exchanges were active in spring and fall but contributed little to carbon sequestration on an annual scale. The summer is the most significant season as far as ecosystem carbon balance is concerned. The 90 days of summer contributed 66.9, 68.9% of FGPp, and 60.4, 62.1% of RE of the entire year.

关键词： old-growth forest eddy-covariance carbon metabolism seasonal and annual dynamics

Geometry of Broad Line Regions of Active Galactic Nuclei

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chinese Journal of Astronomy and Astrophysics 2008年第1期8卷 50-62页

作者： Xiao-rong Lü1 Key Laboratory for Particle Astrophysics, institute of High Energy Physics, chinese academy of sciences, Beijing 100049 2 Graduate School of chinese academy of sciences, Beijing 100049 Key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 Graduate School of chinese academy of sciences Beijing 100049

It has long remained an open question as to the geometry of the broad line region （BLR） in active galactic nuclei （AGNs）. The reverberation mapping technique which measures the response of the broad emission lines to the ionizing continuum, when combined with multiwavelength continuum fitted by sophisticated accretion disks, provides a way of probing the BLR geometry. We analyze a sample of 35 AGNs, which have been monitored by the reverberation mapping campaign. In view of energy budget, the reverberation-based BH masses are found to be in agreement with those obtained by accretion disk models in two thirds of the present sample while the reverberation mapping methods underestimate the BH masses in about one third of objects, as also suggested by CoUin et al. in a recent work. We point out that there are obviously two kinds of BLR geometry, which are strongly dependent on the Eddington ratio, and separated by the value LBol/LEdd - 0.1. These results prefer a scenario of the disk and wind configuration of the BLR and identify the Eddington ratio as the physical driver regulating the wind in the BLR.

关键词： accretion, accretion disks - galaxies active - galaxies Seyfert - quasars general