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Pollution characteristics of atmospheric fine particles and their secondary components in the atmosphere of shenzhen in summer and in winter

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Science china Chemistry 2006年第5期49卷 466-474页

作者： NIU Yuwen1,2.HE Lingyan1,2.HU Min2.ZHANG Jing2.& ZHAO Yunliang2.1. shenzhen Graduate School of Peking university,shenzhen 518055,china 2. State Joint Key Laboratory of Environmental Simulation and Pollution Control,College of Environmental Sciences,Peking university,Beijing 100871,china 1. shenzhen Graduate School of Peking university Shenzhen 518055 China 2. State Joint Key Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences Peking University Beijing 100871 China

Two field measurements for atmospheric fine particles were conducted in Baoan district of shenzhen during the summer and winter in 2.04. Totally 30 sets of 2. h samples were collected, and then the mass concentrations and chemical compositions were determined. The seasonal varia- tions and secondary pollution characteristics of fine particles during the sampling periods were dis-cussed with meteorological factors. The results show that seasonal variations of atmospheric particles are significant in shenzhen. The average mass concentrations of PM2.5 and PM10 in summer were 35 μg·m-3 and 57 μg·m-3, respectively, and those in winter were 99 μg·m-3 and 135 μg·m-3, respec-tively. The concentrations of both PM2.5 and PM10 in winter increased 184% and 137%, respectively, compared to those in summer. PM2.5 accounted for 61% and 75% of PM10 in summer and in winter, respectively, indicating severe fine particle pollution in shenzhen. During the summer and winter sampling periods, the mean OC/EC ratios were 3.4 and 1.6, respectively. The estimated secondary organic carbon (SOC) averagely accounted for 56% and 6% of the total OC in summer and in winter, respectively, which implies a major contribution of SOC to OC in summer. During the continuous high temperature period in summer, both the concentrations and fractions of secondary aerosol compo-nents in PM2.5 were highly elevated, suggesting severe secondary pollution again. The prevailing wind was from South china Sea in summer, and the air quality was good. The prevailing wind in winter was from china's Mainland to the north, and the polluted air mass led to poor air quality.

关键词： PM2.5, mass concentration, secondary pollution, seasonal variation, shenzhen.

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Advances in theory and applications of fuzzy clustering

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Chinese Science Bulletin 2000年第11期45卷 961-970页

作者： GAO Xinbo & XIE Weixin1. institute of Electronic Engineering, Xidian university, Xi’an 710071, {2. 2. President office, shenzhen university, shenzhen 518060, {2.. institute of Electronic Engineering Xidian University Xi’an China President office Shenzhen University Shenzhen China

The summarization and evaluation of the advances in fuzzy clustering theory are made in the aspects including the criterion functions, algorithm implementations, validity measurements and applications. Several importa... 详细信息

关键词： cluster analysis fuzzy clustering cluster validity pattern recognition image processing.

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Multispectral image edge detection via Clifford gradient

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Science china(Information Sciences) 2012年第2期55卷 260-269页

作者： XU Chen2.LIU Hui1,CAO WenMing1 & FENG JiQiang2.1College of Information Engineering,shenzhen university,shenzhen 518060,{2. 2.3} of Intelligent Computing Science,shenzhen university,shenzhen 518060,{2. 2. institute of Intelligent Computing Science Shenzhen University Shenzhen 518060 China1. College of Information Engineering Shenzhen University Shenzhen 518060 China

The edge detection of a multispectral image with a mass of image information is theoretically expected to give a more accurate *** algebra is more suitable for processing multidimensional data and expressing the data association than general ***,the basic properties of Clifford algebra are ***,the Clifford algebra description of a multispectral image is ***,a novel multispectral image edge detection algorithm is proposed in terms of the Clifford *** the first two experiments,comparison of the detail achieved by the new algorithm with that from the maximal entropy edge detection algorithm reveals that the edge detection based on Clifford gradient is better at retaining and identifying edge information of the multispectral image than the maximal entropy edge detection *** experiments using tuberculosis CT image show that the new algorithm has clinical value in reducing risk of misdiagnosis.

关键词： multispectral image edge detection Clifford gradient

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ON THE GENERALIZED INVERSE NEVILLE-TYPE MATRIX-VALUED RATIONAL INTERPOLANTS

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Journal of Computational Mathematics 2003年第2期21卷 157-166页

作者： Zhibing Chen9+(Department of Mathematics, Normal College, shenzhen university, shenzhen 518060, {2.) Department of Mathematics Normal College Shenzhen University Shenzhen 518060

A new kind of matrix-valued rational interpolants is recursively established by means of generalized Samelson inverse for matrices, with scalar numerator and matrix-valued denominator. In this respect, it is essentially different from that of the previous works [7, 9], where the matrix-valued rational interpolants is in Thiele-type continued fraction form with matrix-valued numerator and scalar denominator. For both univariate and bivariate cases, sufficient conditions for existence, characterisation and uniqueness in some sense are proved respectively, and an error formula for the univariate interpolating function is also given. The results obtained in this paper are illustrated with some numerical examples.

关键词： Generalized inverse for matrices Neville-type Rational interpolants.

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Categories and characteristics of urban villages by GIS-based analysis:A case study of the shenzhen Special Economic Zone

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Science china(Technological Sciences) 2010年第S1期53卷 150-157页

作者： TONG De1,FENG ChangChun2.LI GuiCai1 & CHEN Peng1,2.1S henzhen Graduate School,Peking university,shenzhen 518055,{2. 2.ollege of Urban and Environmental Science,Peking university,Beijing 100871,{2. 1. shenzhen Graduate School Peking University Shenzhen 518055 China 2. College of Urban and Environmental Science Peking University Beijing 100871 China

Studies on the characteristics of urban villages have attracted much interest in urban ***,how to advance the development of further theoretical analysis and quantitative methodologies,especially in the era that GIS and digital-urban technologies develop rapidly and provide precious resources on spatial issues,has always been a heated debate and *** this paper,a mathematical model based on spatial analysis is introduced to deal with the categorization and characterization of urban villages.A total of 89 urban villages in the shenzhen Special Economic Zone(SEZ)are used in this case *** ArcGIS tools on buffer analysis,distance and density calculation,and socio-economic and spatial attributes conjunction,urban villages’31 spatial variables in 4 aspects—social,economic,locational,and physical—are extracted,and 6 principal factors are concluded by principal components analysis to indicate the spatial characteristic of urban *** on the 6 principal factors,6 types of urban villages,including rapidly sprawling,large,rapidly industrializing periphery,overcrowded,intensively mobile and economically backward,are divided through the Hierarchical Clustering ***,the spatial features and formation mechanisms of each type of urban villages are ***,the advantages and the shortcomings of the methodology for this specific application are also ***,several guidelines on urban village management and renewal are provided based on the result of type *** outcome of the paper depends on the informational and technological support from the development of digital-city management,and is able to in turn provide basis on monitoring and improving urban villages which can further digital urban framework.

关键词： urban villages GIS-based analysis principal component hierarchical cluster the shenzhen Special Economic Zone (SEZ)

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Approximation algorithm for minimizing relay node placement in wireless sensor networks

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Science china(Information Sciences) 2010年第11期53卷 2332-2342页

作者： LU KeZhong1,2. CHEN GuoLiang1,2. FENG YuHong1,2. LIU Gang1,2.& MAO Rui1,2.1College of Computer Science and Software Engineering, shenzhen university, shenzhen 518060, {2. 2.ational High Performance Computing Center at shenzhen, shenzhen 518060, {2. 1. College of Computer Science and Software Engineering Shenzhen University Shenzhen 518060 China2. National High Performance Computing Center at Shenzhen Shenzhen 518060 China

To eliminate the routing load unbalance among sensor nodes, one approach is to deploy a small number of powerful relay nodes acting as routing nodes in wireless sensor networks, the major optimization objective of which is to minimize the number of relay nodes required. In this paper, we prove that the relay node placement problem in a bounded plane is a P problem, but its computational complexity in general case is quite great. From the geometric cover feature of the relay node placement problem, an O(n2.log n) time greedy approximation algorithm is proposed, where n is the number of sensor nodes. Particularly, at each stage of this algorithm's iterative process, we first select a critical node from uncovered sensor nodes, and then determine the location of relay node based on the principle of preferring to cover the sensor node closer to the critical node, so as to prevent the emergence of isolated node. Experiment results indicate that our proposed algorithm can generate a near optimum feasible relay node deployment in a very short time, and it outperforms existing algorithms in terms of both the size of relay node deployment and the execution time.

关键词： wireless sensor network relay node placement geometrical cover approximation algorithm greedy algorithm

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THz-TDS signal analysis and substance identification via the conformal split

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Science china(Information Sciences) 2012年第1期55卷 49-63页

作者： XIE WeiXin1,2.LI Jing1,2.PEI JiHong2.1School of Electronic Engineering,Xidian university,Xi'an 710071,china {2. Information institute,shenzhen university,shenzhen 518060,china 1. School of Electronic Engineering Xidian University Xi’an 710071 China2. Intelligent Information Institute Shenzhen University Shenzhen 518060 China

A terahertz time-domain spectroscopy(THz-TDS)imaging system can obtain high-dimensional signals with substance fingerprint *** introducing geometric algebra,a novel signal analysis approach to THz-TDS signals is developed based on an optical physical *** this approach,signals are represented with vectors in the high-dimensional real vector *** distribution properties and algebraic relationships of THz-TDS signals are *** is proved that every complex refractive index of substances relates to a unique 2.blade,the vectors corresponding to the samples of the same substance are collinear and belong to the intrinsic 2.blade of the *** decomposed through the conformal split with respect to a 2.blade,THz-TDS signals of high dimensionality can be related to vectors in a 2.dimensional *** on the conformal split properties we deduced,two criteria for substance identification on the basis of THz-TDS signals are ***,a novel substance identification method via the conformal split is *** the method,the 2.blade related to each "known" substance is calculated with two vectors corresponding to THz-TDS signals measured from samples of the substance but with dierent *** the conformal split with respect to those 2.blades,an identified vector corresponding to a THz-TDS signal is linearly related to the vector in a 2.dimensional *** substance of a sample can be identified using criteria on the projected vectors in the *** method can contribute to accurate classification and ***,two experiments are presented that show the feasibility and accuracy of this method.

关键词： terahertz time-domain spectroscopy substance identification geometric algebra conformal split

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Ground state properties of La isotopes in reflection asymmetric relativistic mean field theory

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Science china(Physics,Mechanics & Astronomy) 2009年第10期52卷 1574-1578页

作者： WANG Nan1 & GUO Lu2.1 College of Physics,shenzhen university,shenzhen 518060,{2. 2.Department of Physics,Faculty of Science,university of Tokyo,Tokyo 113-0033,Japan College of Physics Shenzhen University Shenzhen 518060 China Department of Physics Faculty of Science University of Tokyo Tokyo 113-0033 Japan

The ground state properties of La isotopes are investigated with the reflection asymmetric relativistic mean field(RAS-RMF) *** calculation results of binding energies and the quadrupole moments are in good agreements with the *** calculation results indicate the change of the quadrupole deformation with the nuclear mass *** "kink" on the isotope shifts is observed at A = 139 where the neutron number is the magic number N = *** is also found that the octupole deformations may exist in the La isotopes with mass number A ～ 145-155.

关键词： reflection asymmetric relativistic mean field(RAS-RMF) theory nuclear deformation binding energy

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Power minimization with derivative constraints for high dynamic GPS interference suppression

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Science china(Information Sciences) 2012年第4期55卷 857-866页

作者： WU RenBiao 1,2.LI Chan 1 & LU Dan 1 1 Tianjin Key Laboratory for Advanced Signal Processing,Civil Aviation university of china,Tianjin 300300,china 2.Intelligent Information institute of ATR Lab,shenzhen university,shenzhen,518060,china 1. Tianjin Key Laboratory for Advanced Signal Processing Civil Aviation University of China Tianjin 300300 China2. Intelligent Information Institute of ATR Lab Shenzhen University Shenzhen 518060 China

In this paper,a novel adaptive interference suppression algorithm is proposed for high dynamic GPS (global positioning system) *** new method incorporates derivative constraints on the inter-ference DOA (direction of arrival) into power minimization approach,which could broaden the width of nulls in the interferences directions and adapt to the rapid change of the interference *** with the traditional wide nulling algorithm based on the derivative constraints,the new method does not have to know or estimate the DOAs of the desired signal and the *** new method is firstly discussed in the context of spatial processing,and then extended to space-time adaptive processing to mitigate wideband diffusive multipath *** of the new method is verified via simulation examples.

关键词： GPS interference cancellation adaptive arrays space-time adaptive processing high dynamic GPS receiver

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A novel STAP method for the detection of fast air moving targets from high speed platform

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Science china(Information Sciences) 2012年第6期55卷 1259-1269页

作者： WU RenBiao 1,2.JIA QiongQiong 1 & LI Hai 1 1 Tianjin Key Laboratory for Advanced Signal Processing,Civil Aviation university of china,Tianjin 300300,china 2.Intelligent Information institute of ATR Lab,shenzhen university,shenzhen 518060,china 1. Tianjin Key Laboratory for Advanced Signal Processing Civil Aviation University of China Tianjin 300300 China2. Intelligent Information Institute of ATR Lab Shenzhen University Shenzhen 518060 China

Space-time adaptive processing (STAP) is an effective method for detecting moving target in airborne/spaceborne ***,the detection of fast air moving targets from high speed platform is challenged by the range walk of both the clutter and moving *** is well known that keystone formatting can be used to compensate for the range walk of multiple moving targets simultaneously without using the knowledge of the motion ***,in the presence of serious Doppler ambiguity of fast air moving targets,distribution of the clutter will be affected by the keystone formatting matched to the ambiguity number of targets,and as a result the STAP performance will *** this paper,a novel STAP method is proposed for the detection of fast air moving targets from high speed platform,which can deal with the range walk of both clutter and *** of the new method is verified via simulation examples.

关键词： airborne/spaceborne radar keystone formatting space-time adaptive processing (STAP) moving target detection

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