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Estimation of forest volumes by integrating Landsat TM imagery and forest inventory data

Science china(Technological Sciences) 2006年第z1期49卷 54-62页

作者： GU Huiyan, DAI Limin, WU Gang, XU Dong, WANG Shunzhong &WANG Hui Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, china School of Forestry, Northeast Forestry University, Harbin 150040, china state key lab.of Systems Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, beijing 100085, china Graduate University of Chinese Academy of Sciences, beijing 100039, china 1. Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China 2. School of Forestry Northeast Forestry University Harbin 150040 China 3. state key lab.of Systems Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China 4. Graduate University of Chinese Academy of Sciences Beijing 100039 China

Accurate information about forest volumes is essential for forest management planning. The survey interval of the Forest Resource Inventory of china (FRIC) is too long to meet the demand for timely decision-making required for forest protection, management, and utilization. Analysis of satellite imagery provides good potential for more frequent reporting of forest parameters. In this study, we describe an application of the k-nearest neighbors (kNN) method to Landsat TM imagery for improving estimation of forest volumes. Several spectral features were tested and compared in forest volume estimations, including normalized difference vegetation index, environmental vegetation index, and the combination of the spectral features. The combined index resulted in the most accurate volume estimations. The kNN estimator and the combined index were then used in forest volume estimation. The estimation error (RMSE) of the total volume was44.2%, much lower than those for Larix forest (the RMSE was 51.7%) and those for the Korean pine and broadleaved forests (the estimation errors were over 71.7% and 88.19%,respectively). This preliminary study demonstrates the potential of forest volume estimations with remote sensing data to provide useful information for forest management if only limited ground information is available.

关键词： forest inventory, landsat TM, k-nearest neighbors, spectral extraction.

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MULTI-AGENT TRACKING OF A HIGH-DIMENSIONAL ACTIVE LEADER WITH SWITCHING TOPOLOGY

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Journal of Systems Science & Complexity 2009年第4期22卷 722-731页

作者： Yiguang HONG Xiaoli WANG key lab.of Systems and Control,Institute of Systems Science,Academy of Mathematics and Systems Science,Chinese Academy of Sciences,beijing 100190,china. key lab.of Systems and Control Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

This paper considers a multi-agent tracking problem for a high-dimensional active leaderand variable interconnection topology. The state of the leader not only keeps changing but also maynot be measured. To estimate the state such a leader individually, a neighbor-based local controllertogether with a neighbor-based state-estimation rule is given for each autonomous agent. Then, theauthors prove that, with the help of a constructed common Lyapunov function (CLF), each agent cantrack the active leader with unmeasurable states. Finally, the authors explicitly construct a CLF foran active leader with unknown periodic input for illustration.

关键词： Active leader distributed algorithms multi-agent systems switching topology.

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Strategies for managing reservoir sedimentation

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International Journal of Sediment Research 2009年第4期24卷 369-384页

作者： Zhao-yin WANG 1 and Chunhong HU 21 Prof., state key lab.of Hydroscience and Engineering, Tsinghua University, beijing 100084, china. 2 Prof., Secretary General of International Research and Training Center on Erosion and Sedimentation, beijing 100048, china and Vice President of china Institute of Water Resources and Hydropower Research, No. A-1, Fuxing Rd, beijing 100038, china. [a] Prof. state key lab.of Hydroscience and Engineering Tsinghua University beijing 100084 china [b] Prof. Secretary General of International Research and Training Center on Erosion and Sedimentation beijing 100048 china and Vice President of china Institute of Water Resources and Hydropower Research No. A-1 Fuxing Rd beijing 100038 china

Sediment deposition in reservoirs has caused the loss of 66% of the reservoir capacity in china. The main sedimentation control strategies are: 1) storing the clear water and releasing the turbid water; 2) releasing turbidity currents; 3) Draw-down flushing and empty flushing; and 4) dredging. The paper summarizes these strategies with examples. Sediment transport in many Chinese rivers occurs mostly during the 2-4 month flood season, that is, 80-90% of the annual sediment load is transported with 50-60% of the annual runoff. By storing the clear water after the flood season and releasing the turbid water during the flood season, less sediment deposits in the reservoir while the reservoir is still able to store enough water for power generation in the low flow season. The Three Gorges and Sanmenxia reservoirs apply this strategy and control sedimentation effectively. Turbidity currents have become the main sedimentation control strategy for the Xiaolangdi Reservoir. Empty flushing involves reservoir draw-down to temporarily establish riverine flow along the impound reach, flushing the eroded sediment through the outlets. Case studies with the Hengshan Reservoir and Zhuwo Reservoir are presented. Jet dredgers have been used to agitate the reservoir deposit so that the deposit is released from the reservoir with currents. The sediment releasing efficiency is 30-100% for storing the clear and releasing the turbid; 6-40 % for turbidity current; and 2,400-5,500% for empty flushing. Empty flushing causes high ecological stress on the ecosystem to the downstream reaches. Storing the clear and releasing the turbid is the best strategy to control reservoir sedimentation while achieving hydro-power benefit and maintain ecological stability.

关键词： Reservoir sedimentation Storing clear and releasing turbid Flushing Turbidity current Three Gorges Reservoir

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RHEOLOGICAL BEHAVIOR OF EPOXY RESIN WATERBORNE DISPERSIONS

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Chinese Journal of Polymer Science 2001年第5期19卷 471-476页

作者： Zhen-zhong Yang Yuan-ze Xu De-lu Zhao state key laboratory of Polymer Physics & Chemistry, Center for Molecular Science Institute of Chemistry, Chinese Academy of Sciences, beijing 100080 china Chinese Acad Sci Inst Chem State Key Lab Polymer Phys & Chem Ctr Mol Sci Beijing 100080 Peoples R China

The waterborne dispersions of epoxy resin were prepared by the phase inversion emulsification technique. Rheological behavior and its relationship with the structural change of the systems were studied. It was shown that the concentrated dispersions were highly viscoelastic and pseudoplastic, which was attributed to the formation of a physical network among the waterborne particles via hydrogen bond. The dilute dispersions were Newtonian fluids. The discrete clusters composed of small waterborne particles were found in diluted dispersions. With increasing solid content, there existed a structural transition via percolation through a cluster-cluster aggregation mode to form the physical network, which was qualitatively evidenced by the TEM morphologies.

关键词： epoxy resin waterborne dispersion rheological behavior cluster-cluster aggregation percolation transition

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Controllable highly regular triangulation

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Science china(Information Sciences) 2011年第6期54卷 1172-1183页

作者： HUANG Jin, ZHANG MuYang, PEI WenJie, HUA Wei & BAO HuJun CAD&CG state key lab.of Zhejiang University, Hangzhou 310058, china 1. CAD&CG state key lab.of Zhejiang University Hangzhou 310058 China

This paper presents a novel algorithm for generating a highly regular triangle mesh under various user requirements. Three scalar fields are first computed on the input mesh. Then, the intersections of their isocontours with one another are used to construct the highly regular mesh result. The proposed algorithm uses the N-symmetry direction field to guide the edge orientation. Size control is achieved by using a density function on the surface. All user requirements are incorporated into an energy optimization framework of the scalar fields, and then the isocontours of the generated scalar fields are used to construct a high quality result that satisfies all requirements. The experimental results show that the proposed method can successfully handle various user requirements and complex shapes.

关键词： surface remeshing triangulation semi-regular mesh highly regular mesh N-symmetry direction field

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REACTION MECHANISM OF BENZOPHENONE-PHOTOINITIATED CROSSLINKING OF POLYETHYLENE

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Chinese Journal of Polymer Science 2002年第4期20卷 291-307页

作者： Bao-jun Qu state key laboratory of Fire Science and Department of Polymer Science and Engineering University of Science and Technology of china Hefei 230026 china Univ Sci & Technol china State Key Lab Fire Sci Hefei 230026 Peoples R China Univ Sci & Technol china Dept Polymer Sci & Engn Hefei 230026 Peoples R China

The radical intermediates, the crosslink microstructures, and the reaction mechanism of benzophenone (BP)-photoinitiated crosslinking of low-density polyethylene (LDPE) and model compounds (MD) have been reviewed in detail. The spin-trapping electron spin resonance (ESR) spectra obtained from the LDPE/BP systems with spin-trap agents show that two kinds of polymer radical intermediates are mainly formed: tertiary carbon and secondary carbon radicals. The spin-trapping ESR studies of MD/BP systems give further evidence that photocrosslinking reactions of PE predominantly take place a sites of tertiary carbon, secondary carbon, and especially allylic carbon when available. The high resolution C-13-NMR spectra obtained from LDPE and MD systems show that the crosslink microstructures have H- and Y-type links and that their concentrations are of the same order. The fluorescence, ESR, C-13 and H-1-NMR spectra from the PE and MD systems demonstrate that the main photoreduction product of BP (PPB) is benzpinacol formed by the recombination of two diphenylhydroxymethyl (K-.) radical intermediates. Two new PPB products: an isomer of benzpinacol with quinoid structure, 1-phenylhydroxymethylene-4-diphenylhydroxymethyl-2,5-cyclobexadiene and three kinds of alpha-alkyl-benzhydrols have been detected and identified. These results provide new experimental evidence for elucidating the reaction mechanism in the BP-photoinitiated crosslinking of polyethylene.

关键词： photocrosslinking mechanism polymer radical intermediates crosslink microstructures photolytic products of benzophenone polyethylene model compound

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Properties of Novel Antisense Oligonucleotides Containing Isoadenosine （isoA）

Properties of Novel Antisense Oligonucleotides Containing Is...

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第五届全国化学生物学学术会议

作者： Ren-Ping Qiao Jun Zhang Zhen-Jun Yang~* Liang-Ren Zhang Li-He Zhang state key laboratory of natural and biomimetic drugs,School of Pharmaceutical Science,Peking University,beijing 100083

＜正＞Antisense oligonucleotides have been applied extensively for the regulation of cellular and viral gene *** order to improve their binding affinity,RNA specificity and the nuclease stability,we designed and synthesized 3-（S）-（Adenin-9-yl）-4-（R）-hydoxy-5-（S）-（3-hydroxypropyl）-tetrahydronfuran—isoadenosine（isoA）,and

关键词： Isonucleoside Antisense oligonucleotide

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TRANSIENT EFFECT OF A BOGER FLUID FLOWING AROUND A CONFINED CYLINDER

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Chinese Journal of Polymer Science 2001年第4期19卷 377-384页

作者： Xian-feng Li Huai-tian Bu De-lu Zhao state key laboratory of Polymer Physics and Chemistry Center for Molecular Science,Institute of Chemistry, Chinese Academy of Sciences, beijing 100080, china Chinese Acad Sci Inst Chem Ctr Mol Sci State Key Lab Polymer Phys & Chem Beijing 100080 Peoples R China

This paper is concerned with the numerical simulation of the transient effect of an inertialess Boger flow past a confined circular cylinder and the comparison of predictions with particle image velocimetry (PIV) measurements given by Shiang et al.. Dynamic simulation based on the Oldroyd-B constitutive model was carried out using a Lagrangian-Eulerian algorithm. The evolution of velocity field was obtained for the flow at two Deborah (De) numbers, i.e. De = 1.2 and 3.0. At low De, the flow reached steady state rapidly, and showed a symmetric flow regime. However, at high De, the time required to reach steady flow behind the cylinder increased significantly, and the distribution of the velocity field appears to be asymmetric with respect to the stagnation line. Fairly good agreement between the numerical results and the experimental observations is reported. It can be concluded that both the experimental measurements and the present simulations indicate that the elasticity of the polymeric flow strongly affect the flow regime of viscoelastic flow around a confined cylinder.

关键词： transient effect flow around a cylinder Lagrangian-Eulerian algorithm Oldroyd-B model

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NUMERICAL SIMULATION OF FLOW FOLD OF A RIVER WITH COMPLICATED BOUNDARIES

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Journal of Hydrodynamics 1996年第3期8卷 75-80页

作者： Xu Wei-lin Liao Hua-sheng (state key Hydraulics lab. of High Speed Flows, Sichuan Union University, Chengdu 610065, P. R. china) Sichuan Union Univ Chengdu China

The flow field of a river with complicated boundaries is simulated by dividing the calculation domain into several subdomains and using the depth-averaged k-ε turbulence model. The complicated topographic conditions in this paper include bar, confluence, narrow, bay and bend, etc. The lands emerging from the water surface are treated as blocked-off regions. The calculation is achieved at both the low and the high water levels. The velocity profiles along cross-sections are measured at the high water level in physical model. The calculated and measured velocity profiles are in agreement.

关键词： numerical simulation natural river complicated boundary

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Preparation and Characterization of Palladium Colloidal Nanoparticles by Thermal Decomposition of Palladium Acetate with Microwave Irradiation

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Journal of Materials Science & Technology 2005年第2期21卷 187-190页

作者： Yixian CHEN, Baolin HE and Hanfan LIU Hubei key laboratory for Catalysis and Material Science, University of South-Central for Nationalities, Wuhan 430074, china PCLCC, state key laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, beijing 100080, china lab. for Catalysis and Mat. Sci. Univ. of South-Central for Natl. Wuhan 430074 China lab. of Polymer Phys. and Chem. Inst. of Chem. Chinese Acad. of Sci. Beijing 100080 China

A series of solvent-stabilized palladium colloidal nanoparticles were prepared via thermal decomposition of palladium acetate methylisobutylketone (MIBK) solution in the presence of alkali and alcohol with microwave irradiation. The colloidal nanoparticles were characterized with TEM, XPS and XRD. The average diameters of nanoparticles increase from 30 to 40 nm with the increase in concentration of palladium acetate. TEM and XRD observation demonstrated that the palladium colloidal nanoparticles were clusters agglomerated from hundreds of smaller palladium crystallines with size of 3-4 nm. The influence of the concentrations of alkali and alcohol to the particle size was also discussed.

关键词： Thermal decomposition Microwave Palladium acetate Methylisobutylketone

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