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Analysis of forest backscattering characteristics based on polarization coherence tomography

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Science china(Technological Sciences) 2010年第S1期53卷 166-175页

作者： LUO HuanMin 1,LI XiaoWen 1,2.CHEN ErXue 3,CHENG Jian 4 & CAO ChunXiang 2. Institute of Geo-Spatial Information Science and Technology,University of Electronic Science and Technology of china,Chengdu 610054,china 2.{2. Key Laboratory of Remote Sensing Science,Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and beijing Normal University,beijing 100101,china 3Institute of Forest Resources Information Technique of Chinese Academy of Forestry,beijing 100091,china 4 School of Electronic Engineering,University of Electronic Science and Technology of china,Chengdu 610054,china state Key Lab Remote Sensing Sci Beijing 100101 Peoples R China beijing Normal Univ Beijing 100101 Peoples R China Univ Elect Sci & Technol china Inst Geospatial Informat Sci & Technol Chengdu 610054 Peoples R China Chinese Acad Forestry Inst Forest Resources Informat Tech Beijing 100091 Peoples R China Univ Elect Sci & Technol china Sch Elect Engn Chengdu 610054 Peoples R China

It is difficult to make an inventory of vertical profiles of forest structure parameters in field ***,analysis and understanding of forest backscattering characteristics contribute to estimation and detection of forest vertical structure because of the close relationships between backscattering characteristics and structure *** vertical structure function in the complex interferometric coherence definition,which represents the vertical variation of microwave scattering with the penetration depth at a point in the 2.D radar image and can be used to analyze the forest backscattering characteristics,can be reconstructed from polarization coherence tomography(PCT).Based on PCT,the paper analyzes the forest backscattering characteristics and explores the inherent relationship between the result of PCT and the forest structure parameters from numerical simulation of Random Volume over Ground model(RVoG),Polarimetric SAR interferometry(PolInSAR)simulation of forest scene and PolInSAR data at L-band of the test site ***,the effects of the extinction coefficient and surface-to-volume scattering ratio in RVoG model on vertical backscattering characteristics are analyzed by means of numerical ***,by applying PCT to L-band POLInSAR simulations of forest scene,different variations of vertical backscattering due to different extinction coefficients and the ratios of surface-to-volume scattering resulting from different polarizations,forest types and densities are displayed and *** a concept of relative average backscattering intensity is presented,and the factors which affect its vertical distribution are also *** results show that there is high sensitivity of the vertical distribution of forest relative average backscattering intensity to the polarization,forest type and ***,based on repeat pass DLR E-SAR L-band airborne POLInSAR data,the capability of PCT technology for detection

关键词： backscattering characteristic POLInSAR PCT vertical structure function

Numerical modeling of DPSK pressure signals and their transmission characteristics in mud channels

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Petroleum Science 2009年第3期6卷 266-270页

作者： Shen Yue Su Yinao Li Gensheng Li Lin Tian Shouceng College of Physics Science and Technology China University of Petroleum Dongying Shandong 257061 China CNPC Drilling Research Institute Beijing 100083 China state Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum Beijing 102249 China

A numerical model and transmission characteristic analysis of DPSK （differential phase shift keying） pressure signals in mud channels is introduced. With the control logic analysis of the rotary valve mud telemetry, a logical control signal is built from a Gate function sequence according to the binary symbols of transmitted data and a phase-shift function is obtained by integrating the logical control signal. A mathematical model of the DPSK pressure signal is built based on principles of communications by modulating carrier phase with the phase-shift function and a numerical simulation of the pressure wave is implemented with the mathematical model by MATLAB programming. Considering drillpipe pressure and drilling fluid temperature profile along drillpipes, the drillpipe of a vertical well is divided into a number of sections. With water-based drilling fluids, the impacts of travel distance, carrier frequency, drillpipe size, and drilling fluids on the signal transmission were studied by signal transmission characteristic analysis for all the sections. Numerical calculation results indicate that the influences of the viscosity of drilling fluids and volume fraction of gas in drilling fluids on the DPSK signal transmission are more notable than the others and the signal will distort in waveform with differential attenuations of the signal frequent component.

关键词： Measurement while drilling (MWD) modulation binary symbol mathematical model numerical simulation differential phase shift keying (DPSK) signal transmission characteristics

A Physical Simulation Test for the RockBurst in Tunnels

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Journal of Mountain Science 2011年第2期8卷 278-285页

作者： LI Tianbin WANG Xiangfeng MENG Lubo state Key Laboratory of Geohazard Prevention & Geoenvironment {2. Chengdu University of Technology Chengdu 610059 China Sichuan Communication Surveying &Design Institute Chengdu 610017China

According to the test results of the physical and mechanical properties of similar materials in various quality mixture, a type of material with obvious tendency of rockburst was selected to produce a large-size model to simulate rockburst phenomena in tunnels. The prototype model comes from a typical section of diversion tunnels in Jinping Hydropower Station in china. The simulation of excavating tunnels is carried out by opening a hole in the model after loading. The modeling results indicated that under the condition of normal stresses in the model boundaries the arch top, spandrel and side walls of the tunnel produced an obvious jump reaction of stress and strain and the acoustic emission counts of the surrounding rock also increased rapidly in a different time period after the "tunnel" excavation, showing the clear features of rockburst. The spalling, buckling and breaking occurred in the surrounding rock of model in conditions of over loading. It is concluded that the modeling tunnel segment in Jinping Hydropower Station is expected to form the tensile rockburst with the pattern of spalling, buckling and breaking.

关键词： Rockburst Physical simulation Similar materials (Gypsum Cement Sand Water) Strain jump Spalling Buckling Breaking

function of the iron-binding chelator produced by Coriolus versicolor in lignin biodegradation

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Science china(Life Sciences) 2008年第3期51卷 214-221页

作者： WANG Lu1, YAN WenChao1, CHEN JiaChuan2. HUANG Feng1,2.& GAO PeiJi1 1 state Key Laboratory of Microbial Technology, Shandong University, Jinan 2.0100, china 2.Shandong Key Lab of Pulp and Paper Engineering, Shandong Institute of Light Industry, Jinan 2.0100, china state Key Laboratory of Microbial Technology Shandong University Jinan 250100 China Shandong Key Lab of Pulp Paper Engineering Shandong Institute of Light Industry Jinan 250100 China

An ultrafiltered low-molecular-weight preparation of chelating compounds was isolated from a wood-containing culture of the white-rot basidiomycete Coriolus versicolor. This preparation could chelate Fe3+ and reduce Fe3+ to Fe2., demonstrating that the substance may serve as a ferric chelator, oxygen-reducing agent, and redox-cycling molecule, which would include functioning as the electron transport carrier in Fenton reaction. Lignin was treated with the iron-binding chelator and the changes in structure were investigated by 1H-NMR, 13C-NMR, difference spectrum caused by ionization under alkaline conditions and nitrobenzene oxidation. The results indicated that the iron-binding chelator could destroy the β-O-4 bonds in etherified lignin units and insert phenolic hydroxyl groups. The low-molecular-weight chelator secreted by C. versicolor resulted in new phenolic substructures in the lignin polymer, making it susceptible to attack by laccase or manganese peroxidase. Thus, the synergic action of the iron-binding chelator and the lignocellulolytic enzymes made the substrate more acces- sible to degradation.

关键词： Coriolus versicolor lignin degradation iron binding chelator

Temporal and spatial distribution of dam failure events in china

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International Journal of Sediment Research 2008年第4期23卷 398-405页

作者： X.Y.HE 1,Z.Y.WANG 2.and J.C.HUANG 31 Senior Engineer,Department of Water Hazard Research,china Institute of Water Resources and Hydropower Research,beijing 100038,china2.Prof.,state Key Laboratory of Hydroscience and Engineering,Tsinghua University,beijing 100084,china 3 Prof.,Department of Water Hazard Research,china Institute of Water Resources and Hydropower Research,beijing 100038,china [a]Senior Engineer Department of Water Hazard Research china Institute of Water Resources and Hydropower Research beijing 100038 china [b]Prof. state Key Laboratory of Hydroscience and Engineering Tsinghua University beijing 100084 china [c]Prof. Department of Water Hazard Research china Institute of Water Resources and Hydropower Research beijing 100038 china

Reservoirs play a vital role in economic development and flood control. Nevertheless, both human and natural factors may lead to dam failures with catastrophic consequences. Analyzing the data of dam failure events from 1954 to 2.03 and using the method of energy spectrum analysis, this paper studies the periodicity of dam failures. The rate of failure of different dam ages is analyzed. The climate is the main factor affecting the rate of dam failure. Climate diagrams are used to analyze the spatial distribution of dam failure events in china. High rate of dam failure occurs with 2.-year and 12.5-year periods. The distribution of the percentage of dam failure shows an L-shape as a {2. of service age. The first 5 years of operation is known as the "infant period", during which, the probability of dam failure is much higher than during any other periods. The failure rate in areas near or north to the 400 mm annual isopluvial line is notably higher than other areas. In areas with high temperature difference among seasons have a high annual average dam failure rate.

关键词： Dam failure Temporal and spatial distribution Service age Climate diagram

The force of oblique incident wave on the breakwater with a partially perforated wall

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Acta Oceanologica Sinica 2005年第4期24卷 125-134页

作者： LI Yucheng1*, LIU Hongjie2. DONG Guohai11. state Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 11602., china2. Zhejiang Provincial Plan Design & Research Institute of Communications, Hangzhou 310006, china state Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023 China Zhejiang Provincial Plan Design Research Institute of Communications Hangzhou 310006 China

Wave forces induced by the interaction between the oblique incident wave and the breakwater with a partially perforated front wall isinvestigated. The fluid domain is divided into two sub-domains and the eigen-function expansion method is applied to expanding ve-locity potentials in each domain. In the eigen-expansion of the velocity potential, evanescent waves are included. Numerical results ofthe present model are compared with other theories and a good agreement can be found between them. Experimental data have beencompared with the present theoretical results. The effect of the traverse wall on wave forces has been discussed in detail. On the basisof the linear wave theory, it is shown that in the range of engineering practice, the incident angle of wave has small influence on waveforces on the unit length of perforated caisson.

关键词： partially perforated oblique incident wave wave force

Annual integral changes of time serial NDVI in mining subsidence area

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中国有色金属学会会刊：英文版 2011年第S3期21卷 583-588页

作者： MA Chao1, GUO Zeng-zhang1, ZHANG Xiao-ke2. HAN Rui-mei1 1. Key Laboratory of Mine Spatial Information Technologies of state Bureau of Surveying & Mapping, Henan Polytechnic University, Jiaozuo 454000, china 2. School of Coal Mining Engineering, Taiyuan University of Technology, Taiyuan 03002., china [a] Key Laboratory of Mine Spatial Information Technologies of state Bureau of Surveying & Mapping Henan Polytechnic University Jiaozuo 454000 China [b] School of Coal Mining Engineering Taiyuan University of Technology Taiyuan 030024 China

By means of MORTRAN4 model of FLASSH module, an atmospheric correction of the SPOT II/IV data of four-year period for eight experimental coal faces of Lu'an mine area was done. The mining-affected zones were obtained with probability integral method. The normalized difference vegetation index (NDVI) and its mean were obtained by band ratio calculation at the mining subsidence area. Using FOURIER4 model of the fast Fourier transform (FFT) of discrete Fourier analysis theory, the mean NDVI time series data set was reconstructed. With the mean of NDVI transformed into amplitude and the phonological information transformed into phase, the law of NDVI variation by monthly, quarterly, annual were obtained. The annual integral of the time series of NDVI Fourier function (ANDVI) was obtained. The results show that an experience formula of ANDVI variation accompanies with mining time; A fast estimation formula of NPP by means of a coefficient of mining disturbance such as γ.

关键词： Lu’an mine area annual integral of NDVI net primary productivity coefficient of mining disturbance

Numerical investigation of the effect of sub-grid scale eddies on the dispersed particles by LES/FDF model

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Science china(Technological Sciences) 2010年第5期53卷 1304-1308页

作者： JIN HanHui1,CHEN SuTao1,CHEN LiHua1 & FAN JianRen2.1 School of Aeronautics and Astronautics,Zhejiang University,Hangzhou 31002.,china 2.state Key Lab of Clean Energy Utilization,Zhejiang University,Hangzhou 31002.,china 1. School of Aeronautics and Astronautics Zhejiang University Hangzhou 310027 China2. State Key Lab of Clean Energy Utilization Zhejiang University Hangzhou 310027 China

An LES/FDF model was developed by the authors to investigate the SGS effect on the particle motion in the gas-particle two-phase plane wake *** simulation results of dispersion rate for different particles were compared with the results without using the FDF *** was shown that the large eddy structure is the dominant factor influencing the particle diffu-sion in space for small particles(small Stokes-number particles),but for intermediate or large diameter particles,the influence of the sub-grid scale eddies on the dispersion rate is in the same order as that of the large *** sub-grid scale eddies increase the particle dispersion rate in most time,but sometimes they decrease the dispersion *** sub-grid scale particle dispersion rate is decided not only by the intensity of sub-grid scale eddies and the Stokes number of the particles,but also by the large eddy structure of the flow *** the particles in isotropic turbulence,the dispersion rate decreases as the particle diameter increases.

关键词： multiphase flow large eddy simulation filtered density function turbulence sub-grid

Polycyclic Aromatic Hydrocarbons in Agricultural Soils of the Southern Subtropics,china

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Pedosphere 2007年第5期17卷 673-680页

作者： HAO Rong WAN Hong-Fu SONG Yan-Tun JIANG Hong PENG Shao-Lin South china Botanical Garden Chinese Academy of Sciences Guangzhou 510650 （China） Guangdong Key Laboratory of Agricultural environment Pollution Integrated Control Guangdong Institute of Eco- Environment and Soil Sciences Guangzhou 510650 （China） School of Life Science Sun Yat-Sen University Guangzhou 510275 （China） Conservation Biology Institute 260 SW Madison Ave. Suite 106 Corvallis OR 97333 （USA）

The contributions of persistent organic pollutants （POPs） from the subtropical regions of china to pollution of the global environment have been paid great attention; however, little is known about the {2. of POPs in agricultural ecosystems within these regions of china. This study primarily revealed the {2. of the contamination and distribution of polycyclic aromatic hydrocarbons （PAH） in agricultural soils in the subtropical regions. 115 surface soils （0-2. cm） were sampled in the breadbaskets of these regions. The concentrations and types of PAH were determined using gas chromatography linked to mass spectrometry （GC-MS）. The total PAH concentrations ranged from 2..1 to 1 2.6.9 ng g^-1 with a mean of 318.2.± 148.2.ng g^-1. In general terms, the current PAH concentrations were lower than most PAH levels reported in a number of investigations from different countries and regions. PAH isomer ratios indicated that pyrolytic origins, such as fossil fuel combustion related to vehicle tail gas and industrial emissions, were the dominant sources of PAH in the southern subtropical areas of china. Although PAH concentrations decreased with decreasing pollution, population, and traffic density, to a great extent PAH compositions were similar throughout subtropical soils, with naphthalene, phenanthrene, fluoranthene, and benzo（b）fluoranthene being dominant.

关键词： agricultural soils polycyclic aromatic hydrocarbons subtropical region