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Present Status and Future Development of Mobile Internet

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china Communications 2009年第1期6卷 113-118页

作者： Wang Jian1, bi houjie2 1nanjing university, nanjing 210093. china 2nanjing university of posts and telecommunications, nanjing 210003, china nanjing university Nanjing 210093 China nanjing university of posts and telecommunications Nanjing 210003 China

With the integration of telecommunications network and Internet, mobile Internet is bound to rise. Mobile Internet brings not only high-quality business experience; but also enormous challenges to telecommunications. The current status and hierarchical structure of the mobile Internet are presented. Technological advances and market demand are promoting development of mobile Internet, and terminals, networks and businesses are three elements of the development of the mobile Internet. Mobile IP technique and related protocols are described systematically, which are designed to allow mobile terminal and the mobile sub-network to roam within the Internet. Then the IP Multimedia Subsystem (IMS) and its architectural framework are expounded, which are designed by (3GPP). The credible and reliable IP network architecture with Quality of Service (QoS) based on IMS is discussed to meet the needs of the next generation of mobile Internet. Finally, the hotspots such as P2P/ Multicast/ Security are pointed out within the mobile Internet.

关键词： Mobile Internet mobile IP IMS network convergence

A class of fascinating optoelectronic materials: Triarylboron compounds

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Science china Chemistry 2010年第6期53卷 1235-1245页

作者： MOU Xin1,LIU ShuJuan1,DAI ChunLei1,ma TingChun1,ZHAO Qiang1,2,LING QiDan1 & HUANG Wei1 1Key Laboratory for Organic Electronics & Information Displays (KLOEID) and Institute of Advanced materials (IAM),nanjing university of posts and telecommunications,nanjing 210046,china 2State Key Laboratory of Coordination Chemistry,nanjing university,nanjing 210093.china Key Laboratory for Organic Electronics & Information Displays (KLOEID) and Institute of Advanced materials (IAM) Nanjing University of Posts and Telecommunications Nanjing China State Key Laboratory of Coordination Chemistry Nanjing University Nanjing China

Triarylboron compounds are significant optoelectronic materials due to their excellent emissive and electron-transport properties,and could be applied in organic light-emitting diodes as emissive and/or electron-transport *** compounds have vacant pπ orbital and have received increasing interest as fluoride ion and cyanide ion sensors utilizing specific Lewis acid-base *** review summarizes their structural characteristics,optical properties and applications in chemosensors for anions and optoelectronic devices developed in recent years and discusses the problems and prospects.

关键词： OLEDs optical properties sensors structure-property relationships triarylboron compounds

A relative local variational principle for topological pressure

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Science china mathematics 2010年第6期53卷 1491-1506页

作者： ma XianFeng1,CHEN ErCai2,3,& ZHANG AiHua2,4 1Department of mathematics,East china university of Science and Technology,Shanghai 200237,china 2School of mathematics and Computer Science,nanjing Normal university,nanjing 210097,china 3Center of Nonlinear Science,nanjing university,nanjing 210093.china 4College of mathematics and Physics,nanjing university of posts and telecommunications,nanjing 210046,china Department of mathematics East China University of Science and Technology Shanghai China School of mathematics and Computer Science Nanjing Normal University Nanjing China Center of Nonlinear Science Nanjing University Nanjing China College of mathematics and Physics Nanjing University of Posts and Telecommunications Nanjing China

We define the relative local topological pressure for any given factor map and open cover,and prove the relative local variational principle of this *** precisely,for a given factor map π:(X,T)→(Y,S) between two topological dynamical systems,an open cover U of X,a continuous,real-valued function f on X and an S-invariant measure ν on Y,we show that the corresponding relative local pressure P(T,f,U,y) satisfies sup μ∈M(X,T){ hμ(T,U|Y)+∫X f(x)dμ(x) :πμ=ν}=∫Y P(T,f,U,y)dν(y),where M(X,T) denotes the family of all T-invariant measures on ***,the supremum can be attained by a T-invariant measure.

关键词： pressure conditional entropy relative local variational principle

A new measure to characterize multifractality of sleep electroencephalogram

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Science Bulletin 2006年第24期51卷 3059-3064页

作者： ma Qianli1,2,NING Xinbao1,WANG Jun2 & biAN Chunhua1 1. State Key Laboratory of Modern Acoustics,Department of Electronics Science and Engineering,Institute for biomedical Electronic Engi-neering,nanjing university,nanjing 210093.china 2. Province Key Laboratory of Image Processing & Image Communica-tion,College of telecommunications and Information Engineering,nanjing university of posts & telecommunications,nanjing 210003,china State Key Laboratory of Modern Acoustics Department of Electronics Science and Engineering Institute for Biomedical Electronic Engineering Nanjing University Nanjing China Province Key Laboratory of Image Processing & Image Communication College of Telecommunications and Information Engineering Nanjing University of Posts & Telecommunications Nanjing China

Traditional methods for nonlinear dy-namic analysis,such as correlation dimension,Lyapunov exponent,approximate entropy,detrended fluctuation analysis,using a single parameter,cannot fully describe the extremely sophisticated behavior of electroencephalogram (EEG). The multifractal for-malism reveals more “hidden” information of EEG by using singularity spectrum to characterize its nonlin-ear dynamics. In this paper,the zero-crossing time intervals of sleep EEG were studied using multifractal analysis. A new multifractal measure Δasα was pro-posed to describe the asymmetry of singularity spec-trum,and compared with the singularity strength range Δα that was normally used as a degree indi-cator of multifractality. One-way analysis of variance and multiple comparison tests showed that the new measure we proposed gave better discrimination of sleep stages,especially in the discrimination be-tween sleep and awake,and between sleep stages 3 and 4.

关键词： sleep electroencephalogram multifractality.

Research on heart sound identification technology

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Science china(Information Sciences) 2012年第2期55卷 281-292页

作者： CHENG XieFeng1,3,ma Yong2,LIU Chen1,ZHANG XueJun1 & GUO YuFeng11School of Electronic Science and Engineering,nanjing university of posts and telecommunications,nanjing 210003,china 2School of Computer Science and Technology,nanjing university of Science and Technology,nanjing 210094,china 3Key Lab of Broudbard Wireless Communication and Sensor Network Technology(nanjing university of posts and telecommunications),Ministry of Education,nanjing 210094,china School of Electronic Science and Engineering Nanjing University of Posts and Telecommunications Nanjing China Ministry of Education Key Lab of Broudbard Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Nanjing China School of Computer Science and Technology Nanjing University of Science and Technology Nanjing China

In this article,both the basic principles and the experimental methods of identity recognition technology based on heart sounds are ***,the characteristics of heart sounds and the feasibility of heart sounds as a biometric were analyzed.A synthetic model of heart sounds was then developed based on a family of wavelets;Finally,the characteristic parameters of heart sounds were extracted by using the heart sounds linear band frequency cepstra(HS-LBFC)with a specified configuration,and the similarity distance was adopted for heart sound *** highlight the difference in two heart sound signals between the time and frequency domains,a construction method of the heart sound wavelet,a calculation method of the parameters of a synthetic model,selection of the characteristic parameters of heart sounds and the corresponding data processing technology were *** experimental results showed that the proposed method exhibited excellent performance and practicability.

关键词： biometric wavelet family of heart sounds synthetic model of heart sounds heart sounds linear band frequency cepstra(HS-LBFC)

Numerical simulations of the bi-level and branched structure of intracloud lightning flashes

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Science china Earth Sciences 2006年第6期49卷 661-672页

作者： TAN Yongbo1, TAO Shanchang1, ZHU Baoyou1, ma Ming2 & LU Weitao2 1. School of Earth and Space Sciences, university of Science and Technology of china, Hefei 230026, china 2. Chinese Academy of Meteorological Sciences, Beijing 100081, china School of Earth and Space Sciences University of Science and Technology of China Hefei China Chinese Academy of Meteorological Sciences Beijing China

Intracloud (IC) lightning flashes have been simulated in fine resolution (12.5 m) by using a bidirectional stochastic lightning parameterization scheme within 2-dimensional domain. The simu-lated results show that the IC flashes have a bilevel channel structure and the altitudes of the hori-zontal channels are at the same heights of potential wells, which are supported by the previous VHF source observations and balloon soundings of electric field profile in the thundercloud. Further con-clusions are: (1) After an IC flash is initiated near the boundary between positve and nagetive charge zone, the negative (or positive) leader tends to propagate into the positive (or negative) charge zone. Both types of positive and negative IC flashes have been reproduced and their polarity depends on the up and down disposition of the positive and negative charge regions. (2) The extension range of leaders is correlative with the cloud charge distribution. The leader is possible to extend through the inverted charge region all over where it is extending, but keeps away from the isolated charge area of the same polarity. (3) The channel structures also depend on the electric potential distributions in the thundercloud. Before propagating into the central area of potential wells, the leader tends to extend along the direction with the maximum of potential gradient. Once extending away from the center of potential wells, the leader tends to extend along the direction with the slowest potential change. (4) The IC flash channels have the fractal feature with fractal dimension 1.45 before leaders pass through the central area of charge regions. The exponent decreases rapidly once leaders extend into the low-density charge regions. (5) The induced charges of opposite polarity are deposited in the leader channels within preexisting positive and negative charge regions during IC flash discharges. This causes a new and complicated charge distribution in the thundercloud, and the potential

关键词： IC, lightning parameterization, branched bilevel structure, fractal feature, propagation tendency.

N-way blending problem of circular quadrics

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Science china(Information Sciences) 2010年第8期53卷 1546-1554页

作者： FANG MeiE 1,3 , Wang GuoZhao 2 & ma WeiYin 3 1 School of Computer Science, Hangzhou Dianzi university, Hangzhou 310081, china 2 Department of mathematics, Zhejiang university, Hangzhou 310018, china 3 Department of MEEM, City university of Hong Kong, Hong Kong, china School of Computer Science Hangzhou Dianzi University Hangzhou China Department of MEEM City University of Hong Kong Hong Kong China Department of mathematics Zhejiang University Hangzhou China

A method of blending circular quadrics with parametric patches is proposed in this paper. It needs n rational bi-cubic B′ezier patches and two S-patches to blend n (n > 2) quadrics. bi-cubic rational B′ezier patches are used to G 1 -continuously blend each pair of adjacent base surfaces. These patches enclose two n-sided holes. And an S-patch is used to fill each hole, which keeps nearly G 1-continuity. Explicit formulas of control points for both B′ezier patches and S-patches are derived from their constraint conditions, which make modeling by blending quadrics very simple and convenient. In addition, the shapes of the blending surfaces can be intuitively adjusted by free parameters.

关键词： circular quadrics blending n-way S-patch

[[2n ,n]] ADDITIVE QUANTUM ERROR CORRECTING CODES

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Journal of Electronics(china) 2008年第4期25卷 519-522页

作者： Du Yongjun ma Yuefei Department of Applied mathematics Lanzhou University of Technology Lanzhou 730050 China nanjing Research Institute of Electronics Technology Nanjing 210013 China

The self-orthogonal condition is analyzed with respect to symplectic inner product for the binary code that generated by [B1 I B2 B3],where bi are the binary n ×n matrices,I is an identity *** the use of the binary c... 详细信息

关键词： Additive quantum codes binary codes Symplectic inner product Asymptotic good codes

Effects of cooling rate on the microstructure and electrical properties of Dy_2O_3-doped ZnO-based varistor ceramics

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Rare Metals 2007年第1期26卷 39-44页

作者： LIU Hongyu KONG Hui JIANG Dongmei SHI Wangzhou ma Xueming ZHANG Huining Department of Physics East China Normal University Shanghai 200062 China College of Science Wuhan University of Science and Technology Wuhan 430081 China Shanghai Research Institute of Petrochemical Technology Shanghai 201208 China

The microstructure, electrical properties, and density of Dy2O3-doped ZnO-based varistor ceramics, prepared using high-energy ball milling （HEBM） and sintered at 800℃, were investigated by increasing the cooling rate in the order of H （slow cooling in furnace） → L （cooling in furnace） → K （cooling in air）. With the increase in cooling rate, the grain size and density decreased, the breakdown voltage （VIma/mm） increased, and the nonlinear coefficient （α） and leakage current （IL） exhibited extremum. The sample with the cooling type L showed the best properties with the breakdown voltage of 2650 V/ram, o：of 20.3, IL of 5.2 laA, and density of 5.42 g/cm^3. The barrier height （ФB）, donor concentration （Nd）, density of the interface states （Nd）, and barrier width （ω） all exhibited extremum during the alteration in cooling rate. The different relative amount of bi-rich phase and its distribution as well as the characteristic parameters of grain boundary, resulting from the alteration of cooling rate, led to the changes in the properties of varistor ceramics.

关键词： varistor ZnO Dy2O3 microstructure electrical properties high-energy ball milling low-temperature sintering