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Science china(Information Sciences) 2011年第7期54卷 1456-1470页

作者： ZHANG Han 1,DAI XianHua 2.& Pan DaRu 1 1 School of physics and Telecommunication Engineering,South china {2. university,Guangzhou 510006,china 2.department of Information Science and Technology,SUN Yat-sen university,Guangzhou 51002.,china School of physics and Telecommunication Engineering South China Normal University Guangzhou China department of Information Science and Technology SUN Yat-sen University Guangzhou China

We address the problem of estimating the linearly time-varying (LTV) channel of orthogonal frequency division multiplexing (OFDM)/multiple-input multiple-output (MIMO) systems using superimposed training (ST).The LTV channel is modeled by truncated discrete Fourier *** on this model,a two-step approach is adopted to estimate the LTV channel over multiple OFDM *** also present performance analysis of the channel estimation and derive a closed-form expression for the channel estimation *** is shown that the estimation variances,unlike that of the conventional ST-based schemes,approach to a fixed lower-bound as the training length increases,which is directly proportional to information-pilot power *** wireless communication systems with a limited transmission power,we optimize the ST power allocation by maximizing the lower bound of the average channel *** results show that the proposed approach outperforms the frequency-division multiplexed training schemes.

关键词： OFDM/MIMO systems linearly time-varying channel estimation superimposed training training power allocation

An accurate three-dimensional potential energy surface for the He-Na_2.complex

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Science china Chemistry 2008年第6期51卷 539-544页

作者： WANG Yue,HUANG WuYing,FENG ErYin& CUI ZhiFeng department of physics,Anhui {2. university,Wuhu 2.1000,china department of physics Anhui Normal University Wuhu China

An accurate three-dimensional potential energy surface(PES) for the He-Na2.van der Waals comple was calculated at the coupled cluster singles-and-doubles with noniterative inclusion of connecte triple(CCSD(T)) level of theory.A mixed basis set,aug-cc-pVQZ for the He atom and cc-pCVQZ for th sodium atom,and an additional(3s3p2.1f) set of midbond functions were *** computed inte action energies in 819 configurations were fitted to a 96-parameter analytic potential model by leas squares *** PES has two shallow wells corresponding to the T-shaped structure and the linea configuration,which are located at 12.5a0 and 14 a0 with depths of 1.769 and 1.684 cm-1,respectivel The whole potential energy surface exhibits weak *** on the fitted PES,state-to-stat differential cross sections were calculated.

关键词： van der Waals complex potential energy surface ab initio calculation

The dynamical properties of Rydberg hydrogen atom near a metal surface

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Science china(physics,Mechanics & Astronomy) 2005年第6期48卷 667-675页

作者： GE Meihua1, ZHANG Yanhui1, WANG Dehua2. DU Mengli3 & LIN Shenglu1 1. College of physics and Electronics, Shandong normal {2., Jinan 2.0014, china 2. department of Mathematics and physics, Shandong Institute of Architecture and Engineering, Jinan 2.0014, china 3. Institute of Theoretical physics, Chinese Academy of Sciences, Beijing 100080, china College of physics and Electronics Shandong Normal University Jinan China department of Mathematics and physics Shandong Institute of Architecture and Engineering Jinan China Institute of Theoretical physics Chinese Academy of Sciences Beijing China

The dynamical properties of Rydberg hydrogen atom near a metal surface are presented by using the methods of phase space analysis and closed orbit theory. Transforming the coordinates of the Hamiltonian, we find that the phase space of the system is divided into vibrational and rotational region. Both the Poincaré surface of section and the closed orbit theory verify the same conclusion clearly. In this paper we choose the atomic principal quantum number as n = 2.. The dynamical character of the exited hydrogen atom depends sensitively on the atom-surface distance d. When d is sufficiently large, the atom-surface potential can be expressed by the traditional van der Waals force and the system is integrable. When d becomes smaller, there exists a critical value dc. For d > dc, the system is near-integrable and the motion is regular. While chaotic motion appears for d < dc, and the system tends to be non-integrable. The trajectories become unstable and the electron might be captured onto the metal surface.

关键词： Rydberg hydrogen atom, van der Waals interaction, Poincaré surface of section, closed orbit theory, chaos.

Dispersion of Soluble Matters in Newton-dipolar Stratified Fluid and Effects of Peripheral Layer

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Communications in Nonlinear Science and Numerical Simulation 1998年第4期3卷 236-241页

作者： Zhangji LU, Shousheng DONG, Yu SHEN and Guangping ZHENG (department of Mechanics and Engineering Science, Fudan university, Shanghai 2.0433,{2.)(department of physics, East china normal university, Shanghai 2.0062. china) Dept. of Mechanics and Eng. Science Fudan University Shanghai 200433 China department of physics East China Normal University Shanghai 200062 China

In the paper, the dispersion law and the concentration distributions of soluble matters in Newton-dipolar fluids flowing through a circular tube have been investigated. Main results are: (1) for the dependence of M on A (or H), the completely opposite trends are obtained in the cases with and without the peripheral layer. (2. effects of δ on　M have the minimum values near 8=0.85-0.9. (3) various models such as couple stress,micropolar, dipolar, Newton-newtonian, Newton-couple stress and Newton-micropolar　model etc. are all special cases of Newton-dipolar fluid (where Mz=0). WhenMz≠ 0,however, there are evident differences between the Newton-dipolar fluid and the Newtoncouple stress fluid, the Newton-micropolar fluid.

关键词： dipolar fluid dispersion effects of a peripheral layer tube flow of complex fluid

Luminosity function of optically-selected type II QSOs

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Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 191-195页

作者： BIAN WeiHao & ZHANG ShiYan department of physics,Nanjing {2. university,Nanjing 2.0097,china department of physics Nanjing Normal University Nanjing China

For a sample of 411 type II QSOs with redshifts less then 0.3,we use the Balmer decrements to do the reddening correction of the [O III] luminosities and then derive the intrinsic [O III] luminosity *** find that the host reddening correction of the [O III] 5007 luminosity for type II QSOs cannot be *** median Balmer decrement of Hα/Hβ=4.0 corresponds to an extinction of 0.94 mag for the [O III] 5007 line,which is consistent with the result derived from the median Hβ/Hγ.Comparing the intrinsic luminosity function of type II QSOs with that of type I QSOs,we find that the upper limit of the type II QSO’s fraction in the total QSOs is 80% for type II QSOs with z < 0.3 and 8.6≤log(L[O III]/L)≤9.4.

关键词： type II QSOs luminosity function emission lines Balmer decrements

Modelling Accelerating Growth with Intermittent Processes in Evolving Networks

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Communications in Theoretical physics 2007年第12期48卷 1119-1122页

作者： YUAN Wu-Jie~(1,2.and LUO Xiao-Shu~1~1 College of physics and Electronic Engineering,Guangxi normal {2.,Guilin 541004,china~2.department of physics,Huaibei Coal Industry Teachers College,Huaibei 2.5000,china College of physics and Electronic Engineering Guangxi Normal University Guilin 541004 China department of physics Huaibei Coal Industry Teachers College Huaibei 235000 China

In this paper,the acceleratingly growing network model with intermittent processes is *** thegrowing network,there exist both accelerating and intermittent *** network is grown from the number ofnodes mo and the number of links added with each new node is a nonlinearly increasing function m+aNβ（t）f（t）,whereN（t） is the number of nodes present at time t.f（t） is the periodic and bistable function with period T,whose values are1 and 0 indicating accelerating and intermittent processes,*** we denote the ratio r of acceleration timeto whole *** study the degree distribution p（k） of the model,focusing on the dependence of p（k） on the networkparameters τ,T,m,α,N,and β.It is found that there exists a phase transition point,kc such that if kc,then p（k）obeys a power-law distribution with exponent -γ1,while if k>kc,then p（k） exhibits a power-law distribution withexponent-γ2./sub>.Moreover,the exponents γ1 and γ2./sub> are independent of τ,T,m,a,and N,while they depend only onthe parameter β.More interesting,the phase transition point is described by kc=aNβ,which is equal to the value atwhich p（k） is maximum in GM model.

关键词： acceleratingly growing network intermittent process power-law distribution

The littlest Higgs model with T-parity and some lepton flavor violation decay processes

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Science china(physics,Mechanics & Astronomy) 2010年第11期53卷 1968-1974页

作者： YUE ChongXing,MA Wei,ZHANG TingTing,LIU Wei & LIU JinYan department of physics,Liaoning {2. university,Dalian 11602.,china department of physics Liaoning Normal University Dalian China

The new particles predicted by the littlest Higgs model with T-parity (called LHT model) can induce the lepton flavor violation (LFV) couplings at the one-loop level,which can add contributions to some LFV *** into account the constraints of the experimental data on the relevant free parameters,we calculate the branching ratios of the LFV decay processes Z → l ˉl and τ-→μ-P 1 P 2.with P 1 P 2.= π + π-,K + K-,and K0 ˉK 0 in the context of this new physics *** find that the LHT model can indeed make significant contributions to some of these LFV decay *** Z factory option for the future high energy e + e-collider experiments will give severe constraints on the LHT model.

关键词： littlest Higgs model lepton flavor violation branching ratios

Synthesis of vertically aligned carbon nanotube arrays on silicon substrates

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Science china(Technological Sciences) 2004年第5期47卷 616-624页

作者： ZHENG Ruiting1, CHENG Guoan1, PENG Yibin1, 2. ZHAO Yong1, 3, LIU Huaping1 & LIANG Changlin1 1. Key Laboratory of Radiation Beam Technology and Materials Modification of Ministry of Education, department of Materials Science and Engineering, Beijing normal {2., Beijing 100875, china 2. School of Science, Civil Aviation {2. of china, Tianjin 300300, china 3. department of physics, Nanchang {2., Nanchang 330047, china Correspondence should be addressed to Zheng Ruiting Key Laboratory of Radiation Beam Technology and Materials Modification of Ministry of Education Department of Materials Science and Engineering Beijing Normal University Beijing China School of Science Civil Aviation University of China Tianjin China department of physics Nanchang University Nanchang China

The growth of well-aligned carbon nanotube (CNT) arrays using a heat chemical vapor deposition system on silicon substrates is reported. The growth properties of CNT arrays are studied as a function of synthesis conditions. It is found that 750°C and 10 nm Fe film are suitable conditions for the growth of well-aligned CNT arrays. CNT arrays with a uniform diameter, thick tube wall and firm cohesion to the Si substrate can be grown for C2.2.concentration of 2.%. Based on the experiment, the processes of improving the alignment of CNT arrays and cohesion between CNT arrays and Si substrates are discussed.

关键词： carbon nanotubes, vertically aligned, silicon substrate, chemical vapor deposition.

Bloch constant of holomorphic mappings on the unit polydisk of C^n

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Science china Mathematics 2008年第4期51卷 652-659页

作者： WANG JianFei~(1+) LIU TaiShun~2.1 College of Mathematics and physics Information Engineering Zhejiang normal {2. Jinhua 32.004,china 2.department of Mathematics Huzhou Teachers College Huzhou 313000 china College of Mathematics and physics Information Engineering Zhejiang Normal University Jinhua China department of Mathematics Huzhou Teachers College Huzhou China

In this paper,we give a definition of Bloch mappings defined in the unit polydisk D^n, which generalizes the concept of Bloch functions defined in the unit disk *** is known that Bloch theorem fails unless we have some restrictive assumption on holomorphic mappings in several complex *** shall establish the corresponding distortion theorems for subfamiliesβ(K)andβ_(loc)(K) of Bloch mappings defined in the polydisk D^n,which extend the distortion theorems of Liu and Minda to higher *** an application,we obtain lower and upper bounds of Bloch constants for various subfamilies of Bloeh mappings defined in D^*** particular,our results reduce to the classical results of Ahlfors and Landau when n=1.

关键词： Bloch constant Bloch mapping univalent ball critical point Julia lemma locally biholomorphic mapping Landau constant

CODIMENSION 3 BIFURCATIONS OFHOMOCLINIC ORBITS WITH ORBITFLIPS AND INCLINATION FLIPS

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Chinese Annals of Mathematics,Series B 2004年第4期25卷 555-566页

作者： SHUISHULIANG ZHUDEMING CollegeofMathematicsandphysics ZhejiangNormalUniversityJinhua321004ZhejiangChina. departmentofMathematics EastChinaNormalUniversityShanghai200062China.

The homoclinic bifurcations in four dimensional vector fields are investigated by setting up a local coordinates near the homoclinic orbit. This homoclinic orbit is nonprincipal in the meanings that its positive semi-orbit takes orbit flip and its unstable foliation takes inclination flip. The existence, nonexistence, uniqueness and coexistence of the 1-homoclinic orbit and the 1-periodic orbit are studied. The existence of the twofold periodic orbit and three-fold periodic orbit are also obtained.

关键词： Bifurcation Homoclinic orbit Orbit flip Inclination flip Periodic orbit