检索结果-南通市图书馆

Analysis of forest backscattering characteristics based on polarization coherence tomography

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 21 Institute of Geo-Spatial Information science and technology,university of electronic science and technology of china,chengdu 610054,china 2 State 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 Institute of Geo-Spatial Information science and technology University of Electronic Science and Technology of China Chengdu China State 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 China Institute of Forest Resources Information Technique of Chinese Academy of Forestry Beijing China school of electronic engineering University of Electronic Science and Technology of China Chengdu 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

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A New Kind of Millimeter Wave Dual-Circular Polarized Array

A New Kind of Millimeter Wave Dual-Circular Polarized Array

引用

The 8th International Symposium on Antennas,Propagation and EM Theory（ISAPE2008）

作者： DaKui Wu 1,Yong Fan 2,Minghua Zhao 3,Zongrui He 4 school of electronic engineering university of electronic science and technology of china,chengdu,Sichuan 610054,china

A new kind of compact planar dual-circular polarized microstrip array for millimeter wave module was proposed in this *** antenna can radiate left/right hand polarized wave depending on different feeding port which was *** simple modelling of this antenna and design method has been *** different 3D simulation tools were employed to validate the design method of the *** results acquired from both 3D simulation tools exhibit good performance of the return loss and axial *** gain of the array is about 8dBi.

关键词： A New Kind of Millimeter Wave Dual-Circular Polarized Array

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

A regularization method in the electromagnetic inverse scattering problem

引用

Progress in Natural science:Materials International 2007年第3期17卷 346-351页

作者： XIONG Xiaoyun, ZHAO Yanwen and NIE Zaiping (school of electronic engineering, university of electronic science and technology of china, chengdu 610054, china) school of electronic engineering University of Electronic Science and Technology of China Chengdu 610054 China

Based on the normalization of measurement data equations of the inverse scattering problem, a new regularization matrix is proposed. It can eliminate the unfavorable effects caused by difference of distances between field-point or source-point and target region, reduce the loss of useful information in regularization procedure, and decrease condition numbers of the ill-posed problems. Inversion for conductivity distribution of two-dimensional axisymmetric inhomogeneous media is carried out by combing this new regularization method with distorted Born iterative method. Simulation results show that compared with the conventional method, the new regularization method is of better stability, quicker convergence, higher accuracy of inversion and higher resolution.

关键词： inverse scattering regularization distorted Born iterative method.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Adaptive detection for distributed targets in Gaussian noise with Rao and Wald tests

引用

science china(Information sciences) 2012年第6期55卷 1290-1300页

作者： SHUAI XiaoFei,KONG LingJiang & YANG JianYu school of electronic engineering,university of electronic science and technology of china,chengdu 610054,china school of electronic engineering University of Electronic Science and Technology of China Chengdu China

The problem of adaptively detecting a range distributed target or targets in Gaussian interference is considered in this *** is assumed that a set of secondary data is ***,we derive the adaptive Rao and Wald tests with one-step detection algorithm,and find that both of them are of the same asymptotic performance as the GLRT ***,the Rao and Wald tests are derived by resorting to the two-step design *** our surprise,our derivations show that all the Rao,Wald and GLR tests in the two-step design strategy are ***,the property assessments are *** is shown that these new detectors guarantee CFAR property with respect to the Gaussian ***,simulation results show that these results are accurate.

关键词： Rao and Wald tests adaptive detection distributed targets maximum likelihood estimator

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The analyticity of solutions to a class of degenerate elliptic equations

引用

science china Mathematics 2010年第8期53卷 2061-2068页

作者： LI ChunHe school of Mathematical science,university of electronic science and technology of china,chengdu 610054,china school of Mathematical science University of Electronic Science and Technology of China Chengdu China

In the present paper,the analyticity of solutions to a class of degenerate elliptic equations is obtained.A kind of weighted norms are introduced and under such norms some degenerate elliptic operators are of weak coe... 详细信息

关键词： analyticity degenerate elliptic equations weighted norm weak coerciveness

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An improved model of Robinson equivalent circuit analytical model

引用

science china(Technological sciences) 2010年第7期53卷 1993-1999页

作者： MAO XiangYu & DU PingAn school of Mechatronics engineering, university of electronic science and technology of china, chengdu 611731, china school of Mechatronics engineering University of Electronic Science and Technology of China Chengdu China

The Robinson equivalent circuit analytical model can be used only in calculating shielding effectiveness of enclosure with the same multi-holes in one wall, but cannot be used in different multi-holes in two walls. According to the practical requirement, this article uses Konefal's and Farhana's characteristic impedance of apertures to improve the equivalent circuit analytical model in different multi-holes in two walls. The improved equivalent circuit analytical model is more useful than Robinson equivalent circuit analytical model. In the article, all kinds of enclosures are simulated by TLM (Transmission-Line Matrix method) to prove that this improved model is feasible in multimode.

关键词： equivalent circuit improved model apertures shielding effectiveness TLM (Transmission-Line Matrix method)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Single-channel blind separation of overlapped multicomponents based on energy operator

引用

science china(Information sciences) 2010年第1期53卷 147-157页

作者： CAI QuanWei, WEI Ping & XIAO XianCi College of electronic engineering, university of electronic science and technology of china, chengdu 610054, china College of electronic engineering University of Electronic Science and Technology of China Chengdu China

A method utilizing single channel recordings to blind separate the multicomponents overlapped in both time and frequency domains is proposed in this paper. The main idea of the method is based on using the energy operator and differential energy operator to estimate instantaneous frequencies and amplitudes of each component and then to reconstruct these components. This method, due to the good time resolution of the energy operator and differential energy operator, as well as the very low computational complexity, is very useful in real time processing and practical applications. Simulation results demonstrated the effciency of this method.

关键词： single channel time frequency overlap multicomponents separation energy operator differential energy operator

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Effect of Asymmetry in a Bistable System Subject to Multiplicative Colored Noise

引用

Communications in Theoretical Physics 2007年第12期48卷 1059-1062页

作者： ZHOU Yu-Rong~(1,2)GUO Feng~3 and PANG Xiao-Feng~1~1 school of Life science and technology,university of electronic science and technology of china,chengdu 610054,china~2 school of Information and Electric engineering,Panzhihua university,Panzhihua 617000,china~3 school of Automation engineering,university of electronic science and technology of china,chengdu 610054,china school of Life science and technology University of Electronic Science and Technology of China Chengdu 610054 China school of Information and Electric engineering Panzhihua University Panzhihua 617000 China school of Automation engineering University of Electronic Science and Technology of China Chengdu 610054 China

By the method of the stochastic energetics,we investigate the stochastic resonance (SR) phenomenon of anoverdamped Brown particle in an asymmetric bistable potential,driven by external periodical signal and *** expressions have been obtained for the quasi-steady-state probability distribution *** is found thatthe input energy (IE) pumped into the system by the external driving shows an SR-like behavior as a function of thenoise strength,whereas the IE turns to be a monotonic function of the correlation time of the *** effect ofpotential asymmetry is also studied on SR and IE.

关键词： asymmetric bistable system stochastic resonance stochastic energetics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of pH on the peripheral light-harvesting antenna complex for Rhodopseudomonas palustris

引用

science china(Life sciences) 2008年第8期51卷 760-766页

作者： FENG Juan, LI XueFeng & LIU Yan school of Life science and technology, university of electronic science and technology of china, chengdu 610054, china school of Life science and technology University of Electronic Science and Technology of China Chengdu China

In this work steady-state absorption spectroscopy, circular dichroism spectroscopy and sub-micro-second time-resolved absorption spectroscopy were used to investigate the effect of pH on the struc-tures and functions of LH2 complex for Rhodopseudomonas palustris. The results revealed that: (1) B800 Bchla was gradually transformed to free pigments absorbing around 760 nm on the minutes timescale upon the induction of strong acidic pH, and subsequently there disappeared the CD signal for Qy band of B800 in the absence of B800. In addition, Carotenoids changed with the similar tendency to B850 BChl. (2) The introduction of strong basic pH gave rise to no significant changes for B800 Bchla, while B850 BChla experienced remarkable spectral blue-shift from 852 to 837 nm. Similar phe-nomenon was seen for the CD signal for Qy band of B850. Carotenoids displayed strong and pH-independent CD signals in the visible range. (3) In the case of both physiological and basic pH, broad and asymmetrical positive Tn←T1 transient absorption appeared following the pulsed photo-excitation of Car at 532 nm. By contrast, the featureless and weak positive signal was observed on the sub-microsecond timescale in the acidic pH environment. The aforementioned experimental results indicated that acidic pH-induced removal of B800 Bchla prevented the generation of the caro-tenoid triplet state (3Car*), which is known to be essential for the photo-protection function. Neverthe-less, carotenoids can still perform this important physiological role under the basic pH condition, where the spectral blue shift of B850 exerts little effect on the overall structure of the cyclic aggregate, therefore favoring the formation of carotenoid triplet state.

关键词： pH-induced B800-removal triplet state photo-protection function

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On the maximum likelihood method for target localization using MIMO radars

引用

science china(Information sciences) 2010年第10期53卷 2127-2137页

作者： XIA Wei , HE ZiShu & LIAO YuYu school of electronic engineering, university of electronic science and technology of china, chengdu 611731, china school of electronic engineering University of Electronic Science and Technology of China Chengdu China

A multiple-input multiple-output (MIMO) radar uses multiple antennas to simultaneously transmit multiple independent probing signals, and uses multiple antennas to receive the backscattered signals. The modeling of MIMO radar with transmit spatial diversity and coherent reception is addressed herein. The maximum likelihood (ML) method for parameter estimation using MIMO radars is considered, and two approximate ML algorithms are proposed. In the uniform noise scenario, one of the proposed algorithms performs similarly to the delay-and-sum beamformer which is optimal in the ML sense in single target case, while it outperforms the other proposed approximate ML algorithm at the cost of more computational load. In the non-uniform noise scenario, the proposed approximate ML algorithms both outperform the delay-and-sum beamformer. The efficiency of the proposed methods is validated by the simulation results.

关键词： maximum-likelihood multiple-input multiple-output (MIMO) radars parameter estimation

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：