期刊文献+
共找到13篇文章
< 1 >
每页显示 20 50 100
两类微分方程组的特解表达式 被引量:4
1
作者 陈友朋 钱明忠 陈滨 《高等数学研究》 2011年第3期3-5,共3页
利用线性代数工具和复数性质给出两类常系数非齐次线性微分方程组的特解表达式,以简化计算.
关键词 常微分方程组 特解表达式 比较系数法
下载PDF
含两个未知元的微分方程组的特解
2
作者 陈友朋 王作雷 黄娟娟 《高等数学研究》 2014年第3期1-3,共3页
为了简化计算,利用积分因子法和消元法给出含两个未知元的常系数非齐线性微分方程组的特解表达式.
关键词 常微分方程组 特解表达式 积分因子法
下载PDF
一类二阶时变系数线性微分方程的积分解 被引量:1
3
作者 张学元 《湖南工程学院学报(自然科学版)》 2003年第4期88-94,共7页
对一类二阶时变系数线性齐次微分方程和非齐次微分方程引入了特征方程的概念,给出了由其特征根确定通解和特解的积分表达式,推广了经典的二阶常系数线性微分方程和Euler方程的解法.
关键词 二阶时变系数线性微分方程 特征方程 通解和特解的积分表达式
下载PDF
Physical Layer Security in MIMO Wiretap Channels with Antenna Correlation 被引量:4
4
作者 Gangcan Sun Zhuo Han +2 位作者 Jingbo Jiao Zhongyong Wang Dagang Wang 《China Communications》 SCIE CSCD 2017年第8期149-156,共8页
To investigate the impact of antenna correlation on secrecy performance in MIMO wiretap channels with Nakagami-m fading, the expressions of secrecy outage probability and positive secrecy probability were derived. Div... To investigate the impact of antenna correlation on secrecy performance in MIMO wiretap channels with Nakagami-m fading, the expressions of secrecy outage probability and positive secrecy probability were derived. Diversity order and array gain were also achieved for further insight. The study was based on the information theory that physical layer security can be guaranteed when the quality of the main channel is higher than that of the eavesdropper's channel. Monte Carlo simulations well validated the numerical results of analytic expressions. It was shown that antenna correlation is detrimental to secrecy performance when average SNR of the main channel is at medium and high level. Interestingly, when average SNR of the main channel reduces to low level, the effect of antenna correlation becomes benefi cial to secrecy performance. 展开更多
关键词 physical layer security antenna correlation wiretap channels outage probability Nakagami-m fading
下载PDF
A special solution to transmission capacity of ad hoc networks
5
作者 陈昌海 Yin Changchuan +1 位作者 Li Nana Yue Guangxin 《High Technology Letters》 EI CAS 2011年第1期64-68,共5页
This paper presents an approximate expression to transmission capacity of ad hoc networks by using stochastic geometry. For there is no general close-form expression to the transmission capacity of ad hoc networks, by... This paper presents an approximate expression to transmission capacity of ad hoc networks by using stochastic geometry. For there is no general close-form expression to the transmission capacity of ad hoc networks, by using Taylor series, we obtain the exact series expression to transmission capacity first, then we take partial summation to yield an n-th order approximate expression. Further- more, compared with the exact expression under a special case, the accuracy of the n-th order ap- proximation has been studied. The numerical results show that the accuracy of the approximation is mainly determined by the order n, and a high accuracy can be obtained when the node density or the outage constraint is close to zero . 展开更多
关键词 ad hoc transmission capacity outage constraint APPROXIMATION normalized interference
下载PDF
Generalised Closed-Form Symbol Error Rate Analysis for Orthogonal Space-Time Block Coded OFDM System
6
作者 王旭东 吴楠 高春丽 《China Communications》 SCIE CSCD 2013年第9期155-164,共10页
In this paper,the Symbol Error Rate(SER)performance for Orthogonal Space-Time Block Coded(OSTBC)Orthogonal Frequency Division Multiplexing(OFDM)systems over Nakagami-m fading channels is analysed.A novel closed-form S... In this paper,the Symbol Error Rate(SER)performance for Orthogonal Space-Time Block Coded(OSTBC)Orthogonal Frequency Division Multiplexing(OFDM)systems over Nakagami-m fading channels is analysed.A novel closed-form SER expression is proposed,which incorporates the Gauss hypergeometric function and Appell hypergeometric function into the conventional Probability Density Function(PDF)approach.The proposed exact closed-form SER expression is a generalised solution since it perfectly captures OSTBCOFDM systems’performances when having different antenna configurations that employ various modulation schemes and which experience various fading conditions.Finally,Monte Carlo simulation results are provided to demonstrate the exact match between the simulation results and the proposed analytical expressions. 展开更多
关键词 OSTBC-OFDM closed-form SER Nakagami-m fading channel
下载PDF
Three Semi-empirical Analytic Expressions for the Radial Distribution Function of Hard Spheres
7
作者 SUNJiu-Xun CAILing-Gang +1 位作者 WUQiang JINGFu-Qian 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第3期400-404,共5页
Three simple analytic expressions satisfying the limitation condition at low densities for the radial distribution function of hard spheres are developed in terms of a polynomial expansion of nonlinear base functions ... Three simple analytic expressions satisfying the limitation condition at low densities for the radial distribution function of hard spheres are developed in terms of a polynomial expansion of nonlinear base functions and the Carnahan-Starling equation of state. The simplicity and precision for these expressions are superior to the well-known Percus Yevick expression. The coefficients contained in these expressions have been determined by fitting the Monte Carlo data for the first coordination shell, and by fitting both the Monte Carlo data and the numerical results of PercusYevick expression for the second coordination shell. One of the expressions has been applied to develop an analytic equation of state for the square-well fluid, and the numerical results are in good agreement with the computer simulation data. 展开更多
关键词 radial distribution function hard spheres equation of state square-well fluids
下载PDF
Nonlocality of Two-Qubit and Three-Qubit Schmidt-Correlated States
8
作者 赵明镜 李宗国 +3 位作者 李波 费少明 王志玺 李先清 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第8期253-257,共5页
We investigate the nonlocality of Schmidt-correlated (SC) states, and present analytical expressions of the maximum violation value of Bell inequalities. It is shown that the violation of Clauser-Horne-Shimony-Holt ... We investigate the nonlocality of Schmidt-correlated (SC) states, and present analytical expressions of the maximum violation value of Bell inequalities. It is shown that the violation of Clauser-Horne-Shimony-Holt (CHSH) inequality is necessary and sufficient for the nonlocality of two-qubit SC states, whereas the violation of the Svetlichny inequaJity is only a sumcient condition for the genuine nonlocality of three-qubit SC states. Furthermore, the relations among the maximum violation values, concurrence, and relative entropy entanglement are discussed. 展开更多
关键词 SEPARABILITY entanglement Bell inequality
下载PDF
Solutions of the Schrdinger Equation for PT-Symmetric Coupled Quintic Potentials in Two Dimensions
9
作者 Savita Fakir Chand 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第9期419-422,共4页
This paper deals with the solutions of time independent Schrodinger wave equation for a two-dimensional PT-symmetric coupled quintic potential in its most general form. Employing wavefunction ansatz method, general an... This paper deals with the solutions of time independent Schrodinger wave equation for a two-dimensional PT-symmetric coupled quintic potential in its most general form. Employing wavefunction ansatz method, general analytic expressions for eigenvalues and eigenfunctions for first four states are obtained. Solutions of a particular case are also presented. 展开更多
关键词 Schrodinger equation quintic potential PT-syrametry EIGENVALUE EIGENFUNCTION
下载PDF
A relaxation scheme for a multi-class Lighthill-Whitham-Richards traffic flow model 被引量:6
10
作者 Jian-zhong CHEN Zhong-ke SHI Yan-mei HU 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2009年第12期1835-1844,共10页
We present a high-resolution relaxation scheme for a multi-class Lighthill-Whitham-Richards (MCLWR) traffic flow model. This scheme is based on high-order reconstruction for spatial discretization and an implicit-expl... We present a high-resolution relaxation scheme for a multi-class Lighthill-Whitham-Richards (MCLWR) traffic flow model. This scheme is based on high-order reconstruction for spatial discretization and an implicit-explicit Runge-Kutta method for time integration. The resulting method retains the simplicity of the relaxation schemes. There is no need to involve Riemann solvers and characteristic decomposition. Even the computation of the eigenvalues is not required. This makes the scheme particularly well suited for the MCLWR model in which the analytical expressions of the eigenvalues are difficult to obtain for more than four classes of road users. The numerical results illustrate the effectiveness of the presented method. 展开更多
关键词 Relaxation scheme Multi-class LWR model Traffic flow CWENO reconstruction Implicit-explicit Runge-Kutta
原文传递
Theoretical analysis of the harmonic characteristics of modular multilevel converters 被引量:10
11
作者 XIAO HuangQing XU Zheng +1 位作者 XUE YingLin TANG Geng 《Science China(Technological Sciences)》 SCIE EI CAS 2013年第11期2762-2770,共9页
To understand the operation principle of the modular multilevel converter(MMC)deeply,it is necessary to study the harmonic characteristics of the MMC theoretically.Besides,the analytical harmonic formulas of the MMC a... To understand the operation principle of the modular multilevel converter(MMC)deeply,it is necessary to study the harmonic characteristics of the MMC theoretically.Besides,the analytical harmonic formulas of the MMC are useful in designing the main circuit,reducing the losses and improving the waveform quality.Based on the average switching function and the Fourier series harmonic analysis,this paper deduces the analytical expressions for such electrical quantities as the arm voltage,the arm current,the capacitor voltage,the capacitor current and the circulating current of the MMC.Finally,a digital model of a 21-level MMC-HVDC system is realized in PSCAD/EMTDC.The results of the analytical expressions coincide with the simulation results,which verify the effectiveness and feasibility of the proposed analytical expressions. 展开更多
关键词 modular multilevel converter harmonic characteristics average switching function Fourier series analysis PSCAD/EMTDC
原文传递
Fidelity and fidelity susceptibility based on Hilbert-Schmidt inner product
12
作者 LIU Jing LU XiaoMing +1 位作者 MA Jian WANG XlaoGuang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第9期1529-1534,共6页
We reinvestigate the fidelity based on Hilbert-Schmidt inner product and give a simplified form.The geometric meaning of the fidelity is clarified.We then give the analytic expression of the fidelity susceptibility in... We reinvestigate the fidelity based on Hilbert-Schmidt inner product and give a simplified form.The geometric meaning of the fidelity is clarified.We then give the analytic expression of the fidelity susceptibility in both Hilbert and Liouville space.By using the reconstruction of symmetric logarithmic derivative in Liouville space,we present the time derivative of fidelity susceptibility with the normalized density vector representation. 展开更多
关键词 FIDELITY fidelity susceptibility Liouville space
原文传递
Analytic Expression of Geometric Discord in Arbitrary Mixture of any Two Bi-qubit Product Pure States
13
作者 谢传梅 刘益民 +1 位作者 邢航 张战军 《Communications in Theoretical Physics》 SCIE CAS CSCD 2015年第4期439-444,共6页
Quantum correlations in a family of states comprising any mixture of a pair of arbitrary bi-qubit product pure states are studied by employing geometric discord [Phys. Rev. Lett. 105(2010) 190502] as the quantifier. F... Quantum correlations in a family of states comprising any mixture of a pair of arbitrary bi-qubit product pure states are studied by employing geometric discord [Phys. Rev. Lett. 105(2010) 190502] as the quantifier. First, the inherent symmetry in the family of states about local unitary transformations is revealed. Then, the analytic expression of geometric discords in the states is worked out. Some concrete discussions and analyses on the captured geometric discords are made so that their distinct features are exposed. It is found that, the more averagely the two bi-qubit product states are mixed, the bigger geometric discord the mixed state owns. Moreover, the monotonic relationships of geometric discord with different parameters are revealed. 展开更多
关键词 mixture of a pair of arbitrary bi-qubit product pure state geometric discord inherent symmetry of local unitary transformation m
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部