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Photosynthetically active radiation retrieval based on HJ-1A/B satellite data

Science China Earth Sciences 2010年第S1期53卷 81-91页

作者： LI Li1,XIN XiaoZhou1,SU GaoLi1,2 & LIU QinHuo1 1 State Key Laboratory of Remote Sensing Science,Institute of Remote Sensing Applications,Chinese Academy of Sciences,Beijing 100101,China 2 zhejiang climate center,hangzhou 310017,China 1. State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing 100101 China2. Zhejiang Climate Center Hangzhou 310017 China

Photosynthetically active radiation(PAR) is essential for plant photosynthesis and carbon cycle,and is also important for meteorological and environmental *** advance China's disaster and environmental monitoring capabilities,the HJ-1A/B satellites have been placed in Earth *** of their environmental monitoring objectives is the study of *** simulated direct solar,scattered and environment radiation between 400 and 700 nm under different atmospheric parameters(solar zenith angle,atmospheric water vapor,atmospheric ozone,aerosol optical thickness,surface elevation and surface albedo),and then established a look-up table between these input parameters and *** on the look-up table,we used HJ-1A/B aerosol and surface albedo outputs to derive the corresponding *** of inversed instantaneous and observed PAR values using HJ-1 Heihe experimental data had a root mean square error of 25.2 W m-2,with a relative error of 5.9%.The root mean square error for accumulated daily PAR and observed values was 0.49 MJ m-2,with a relative error of 3.5%.Our approach improved significantly the computational efficiency,compared with using directly radiation transfer *** also studied the sensitivity of various input parameters to photosynthetically active radiation,and found that solar zenith angle and atmospheric aerosols were sensitive PAR *** albedo had some effect on PAR,but water vapor and ozone had minimal impact on PAR.

关键词： Photosynthetically active radiation 6S HJ-1A/B satellites

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Lipschitz continuity of best approximations and Chebyshev centers

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Chinese Science Bulletin 1998年第3期43卷 185-188页

作者： LI Chong 1 and WANG Xinghua 2 1. center for Mathematical Sciences, zhejiang University, hangzhou 310027, China 2. Department of Mathematics, hangzhou University, hangzhou 310028, China center for Mathematical Sciences Zhejiang University Hangzhou China Department of Mathematics Hangzhou University Hangzhou China

The Lipschitz continuity results are given for best approximations and Chebyshev centers. Consequently, the open problem presented by Septycki and Vleck is solved completely.

关键词： best approximation Chebyshev center uniform convexity.

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Complete hypersurfaces in a 4-dimensional hyperbolic space

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Applied Mathematics(A Journal of Chinese Universities) 2009年第3期24卷 370-378页

作者： XU Hong-wei1 ZHAO En-tao2 center of Mathematical Sciences,zhejiang University,hangzhou 310027,China center of Mathematical Sciences Zhejiang University Hangzhou 310027 China

This paper gives a classification of complete hypersurfaces with nonzero constant mean curvature and constant quasi-Gauss-Kronecker curvature in the hyperbolic space H4（-1）,whose scalar curvature is bounded from below.

关键词： complete hypersurface mean curvature quasi-Gauss-Kronecker curvature

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^7Be content and its seasonal variation in the ground air around hangzhou area

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Nuclear Science and Techniques 1999年第4期10卷 230-234页

作者： JIANG Rangrong(zhejiang Province Environmental Radiation Monitoring center, hangzhou 310012) zhejiang Province Environmental Radiation Monitoring center Hangzhou 310012 China

Twice investigations around hangzhou area show that ^7Be content average in the ground air is 5.9mBq.m^-*** content of ^7Be is the highest in autumn-winter period reaching about 7.7mBq.m^-3,the next is in spring about 6.2mBq.m^-*** is in the early summer about 5.7mBq.m^-3,close to the annual average level;and the lowest in a year is in summer-autumm period with a value about 3.8mBq.m^-*** is a decreasing trend from autumn-winter period to summer-autumn of the next year,which is negatively correlated with the variation of the seasonal rainfall in hangzhou *** this trend is different from that reported by UNSCEAR:it is the highest in spring and the lowest in the late autumn,which is based only on ^7Be falling down from the ***,the present investigation shows that the seasonal rainfall is the main factor influencing the variation tend of ^7Be content in the air.

关键词： ^7Be hangzhou域浓度

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The first eigenvalue of Laplace operator under powers of mean curvature flow

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Science China Mathematics 2010年第7期53卷 1702-1709页

作者： ZHAO Liang center of Mathematical Sciences, zhejiang University, hangzhou 310027, China 1. center of Mathematical Sciences Zhejiang University Hangzhou 310027 China

In this paper, we derive the evolution equation for the first eigenvalue of Laplace operator along powers of mean curvature flow. Considering a compact, strictly convex n-dimensional surface M without boundary, which is smoothly immersed in R n+1 , we prove that if the initial 2-dimensional surface M is totally umbilical, then the first eigenvalue is nondecreasing along the unnormalized H k -flow. Moreover, as applications of the evolution equation, we construct some monotonic quantities along this kind of flow.

关键词： Laplace operator H k -flow eigenvalue monotonicity

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Quasi-static Analysis of Thrust-loaded Angular Contact Ball Bearings Part Ⅱ:Results and Discussion

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Chinese Journal of Mechanical Engineering 2012年第1期25卷 81-87页

作者： CHEN Wenhua1,2,MA Zikui1,GAO Liang1,LI Xinglin3,and PAN Jun2 1 Institute of Mechanical Design,zhejiang University,hangzhou 310027,China 2 Institute of Mechanical Design and Manufacturing,zhejiang Sci-Tech University,hangzhou 310018,China 3 State Testing Laboratory of hangzhou Bearing Test & Research center,hangzhou 310022,China 1. Institute of Mechanical Design Zhejiang University Hangzhou 310027 China 2. Institute of Mechanical Design and Manufacturing Zhejiang Sci-Tech University Hangzhou 310018 China 3. State Testing Laboratory of hangzhou Bearing Test & Research center Hangzhou 310022 China

Ball bearings are widely employed mechanical components characterized by high precision and quality,and usually play important roles in various rotary machines and *** advanced applications require a deep understanding of their various kinematic and tribological characteristics that are essential to predict the fatigue endurance,relieve the vibration and minimize the power dissipation of ball bearings in particular *** angular contact ball bearing under a specified operating condition is simulated with the quasi-static/creepage analytical model proposed in the preceding *** results demonstrate that the ball bearing is a statically determinate *** the balls spin on both inner and outer races means the ball is controlled by neither the inner nor the outer *** friction between the ball and raceway renders the inner and outer contact angles *** larger the coefficient of friction is,the larger the angle *** tangential traction perpendicular to the rolling direction due to the spin induces a gyro-like rotation of the ball with respect to the raceway even if no inertial effects are *** tangential elastic compliance of contacting surfaces gives rise to locked areas within the contact patch and transforms the sliding lines from circles into *** differential slip due to the close conformity of the ball and raceway makes the sliding and traction distributions asymmetric,which will influence the location of the spinning center of the ball with respect to the *** quasi-static/creepage model can be used to reveal the operating behaviors of ball bearings running under steady conditions and to optimize the design of ball bearings for specific applications.

关键词： ball bearing quasi-static creepage differential slip tangential elastic compliance

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General expansion for period maps of Riemann surfaces

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Science China Mathematics 2010年第8期53卷 2021-2030页

作者： YIN FangLiang center of Mathematical Sciences,zhejiang University,hangzhou 310027,China 1. center of Mathematical Sciences Zhejiang University Hangzhou 310027 China

In this paper,we get the full expansion for period map from the moduli space Mg of curves to the coarse moduli space Ag of g-dimensional principally polarized abelian varieties in Bers *** generalizes fully the famous Rauch's variational *** applications,we compute the curvature of Siegel metric at point [X] with Π([X]) =√ -1 Ig and the Christoffel symbols of L2-induced Bergman metric on Mg.

关键词： period map moduli space Siegel metric Bergman metric

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Surface electromagnetic modes contribution to the anomalous terahertz transmission through double-layered metal hole array

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Science China(Information Sciences) 2012年第1期55卷 90-97页

作者： RAO Lei1&YANG DongXiao1,2 1Department of Information Science and Electronic Engineering,zhejiang University,hangzhou 310027,China 2Research center for Terahertz Technology,zhejiang University,hangzhou 310027,China 1. Department of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China2. Research Center for Terahertz Technology Zhejiang University Hangzhou 310027 China

Terahertz transmission spectra through both single-layered and double-layered sub-wavelength metal hole arrays were calculated using rigorous mode-matching *** dispersion relations of the single-layered and double-layered metal hole arrays were obtained by FDTD *** are three anomalous peaks in the spectrum of the double-layered metal hole array,which arise from the three surface electromagnetic modes appearing in the dispersion *** comparing the transmission spectra and the dispersion relations of the single-layered and double-layered metal hole arrays,it was found that the two surface electromagnetic modes at higher frequencies are introduced by the single-layered metal hole array,while the one at lower frequencies is introduced by the double-layered metal hole *** validity of the analysis was qualitatively verified by the experimental *** structure can be finely designed for potential applications,such as wideband filtering.

关键词： surface electromagnetic modes double-layered metal hole array terahertz

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TRIPLE　INTERACTIONS　OF　CONORMAL　WAVES　FOR　HIGHER　ORDER　SEMILINEAR　HYPERBOLIC　EQUMIONS

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Chinese Annals of Mathematics,Series B 1995年第1期16卷 23-32页

作者： FANG DAOYUAN (center for Mathematical Sciences, zhejiang University, hangzhou 310027, China.) 浙江大学数学科学中心浙江杭州

The interaction of three conormal waves for semi-linear strictly hyperbolic equations of third order is considered. Let Σi, i = 1, 2, 3, be smooth characteristic surfaces for P= Da(D_t￣2 -△) intersecting transversally at the origin. Suppose that the solution u to Pu = f(t, x ,y)D u), ≤2 is conormal to Σi, i = 1, 2, 3, for t 2, 3.

关键词： Hyperbolic equation Conormal wave Interaction Characteristic surface.

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Influence of viscosity on the phase transformation of amorphous calcium carbonate in fluids:An understanding of the medium effect in biomimetic mineralization

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Science China Chemistry 2010年第10期53卷 2208-2214页

作者： XIE YiDong, XU XuRong & TANG RuiKang center for Biomaterials and Biopathways and Department of Chemistry, zhejiang University, hangzhou 310027, China 1. center for Biomaterials and Biopathways and Department of Chemistry Zhejiang University Hangzhou 310027 China

Biological mineral generation via an amorphous precursor is a topic of great current interest. Various factors such as the temperature, solution composition and presence of organic molecules can influence this important inorganic process. Here we demonstrate that this mineral transformation can actually readily be regulated by solution viscosity, a fundamental but often overlooked property. In our experiment, amorphous calcium carbonate (ACC), a key model compound in biomimetic mineralization studies, is synthesized and dispersed into inert dispersants with different viscosities and the crystallization process is examined by using FT-IR spectroscopy and XRD. It is found that the inhibition of the transformation of ACC becomes more significant with increasing fluid viscosity. This phenomenon can be explained by the differences in ion diffusion in different media. Furthermore, the resulting crystals always have different morphologies and size distributions although they all have the calcite structure. This study implies that the importance of the fluid medium cannot be ignored in building a complete understanding of biological control of biomimetic crystallizations.

关键词： mineralization amorphous calcium carbonate transformation viscosity

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