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一种基于偶数格的格型矢量量化方法
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作者 谢昭 胡瑞敏 《计算机工程与应用》 CSCD 北大核心 2008年第31期153-155,163,共4页
提出一种适用于音频信号的格型矢量量化方法,该方法利用偶数格的特点实现快速的索引分配以及基础码本的压缩存储;将基础码本与球型扩展方法相结合,减小感知重要频带的量化误差。经实验验证,此方法与ITU-T的G729.EV标准中矢量量化效果相当。
关键词 型矢量量化 偶数格 索引分配 球型扩展
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First-Principles Study on Switching Performance and Spin Filtering Efficiency of Dimethyldihydropyrene/Cyclophanediene Single-Molecule Devices with Zigzag Graphene Nanoribbon Electrodes
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作者 Chang-Feng Zheng Yan-Qi Mu +1 位作者 Zong-Liang Li Guang-Ping Zhang 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2024年第5期644-652,I0066-I0072,I0100,共17页
Moleculardeviceswith highswitchingperformance and/or the perfect spin filtering effect have always been the pursuit with the development of molecular electronics.Hereb,yusingthe 2001.0V nonequilibrium.Green's func... Moleculardeviceswith highswitchingperformance and/or the perfect spin filtering effect have always been the pursuit with the development of molecular electronics.Hereb,yusingthe 2001.0V nonequilibrium.Green's function method in combination with the density functionaltheory,the switching performance and spin filtering properties of dimethyldihydropyrene(DHP)/cyclophanediene(CPD)photoswitchable molecule connected by carbon atomic chains(CACs)to two zigzag graphene nanoribbon electrodes have been theoretically investigated.The results show that DHP is more conductive than CPD and therefore an evident switching effect is demonstrated,and the switching ratio(RON/OFF)can reach 4.5×103.It is further revealed that the RoON/OF of DHP/CPD closely depends on the length of CACs.More specifically,the RoN/OFF values of DHP/CPD with odd-numbered CACs are larger than those with even-numbered CACs.More interestingly,a high or even perfect spin filtering effect can be obtained in these investigated DHP/CPD single-molecule devices.Our study is helpful for future design of single-molecule switches and spin filters and provides a way to optimize their performance by means of varying the length of bridging CACs. 展开更多
关键词 Single-molecule switch Spin filtering effect Odd-even effect Nonequilibrium Green's function method Density functional theory
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Application of Exp-Function Method to Discrete Nonlinear Schrdinger Lattice Equation with Symbolic Computation 被引量:2
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作者 JI Jie 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第12期1279-1282,共4页
In this paper, we present an extended Exp-function method to differential-difference equation(s). With the help of symbolic computation, we solve discrete nonlinear Schrodinger lattice as an example, and obtain a se... In this paper, we present an extended Exp-function method to differential-difference equation(s). With the help of symbolic computation, we solve discrete nonlinear Schrodinger lattice as an example, and obtain a series of general solutions in forms of Exp-function. 展开更多
关键词 Exp-function solutions discrete nonlinear SchrSdinger lattice equation
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A New Integrable Lattice Hierarchy and Its Two Discrete Integrable Couplings 被引量:1
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作者 DONG Huan-He SONG Ming +1 位作者 WANG Xue-Lei LI Jian-Jun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第5期1114-1118,共5页
A new and efficient way is presented for discrete integrable couplings with the help of two semi-direct sum Lie algebras. As its applications, two discrete integrable couplings associated with the lattice equation are... A new and efficient way is presented for discrete integrable couplings with the help of two semi-direct sum Lie algebras. As its applications, two discrete integrable couplings associated with the lattice equation are worked out. The approach can be used to study other discrete integrable couplings of the discrete hierarchies of solition equations. 展开更多
关键词 integrable lattice Lie algebra integrable couplings
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A predual of a predual of B_σ and its applications to commutators
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作者 Yoshihiro Sawano Hiroko Yoshida 《Science China Mathematics》 SCIE CSCD 2018年第8期1437-1472,共36页
A predual of B_σ-spaces is investigated. A predual of a predual of B_σ-spaces is also investigated,which can be used to investigate the boundedness property of the commutators. The relation between Herz spaces and l... A predual of B_σ-spaces is investigated. A predual of a predual of B_σ-spaces is also investigated,which can be used to investigate the boundedness property of the commutators. The relation between Herz spaces and local Morrey spaces is discussed. As an application of the duality results, one obtains the boundedness of the singular integral operators, the Hardy-Littlewood maximal operators and the fractional integral operators, as well as the commutators generated by the bounded mean oscillation(BMO) and the singular integral operators.What is new in this paper is that we do not have to depend on the specific structure of the operators. The results on the boundedness of operators are formulated in terms of B_σ-spaces and B_σ-spaces together with the detailed comparison of the ones in Herz spaces and local Morrey spaces. Another application is the nonsmooth atomic decomposition adapted to B_σ-spaces. 展开更多
关键词 B_σ-spaces DUALITY DECOMPOSITION Herz spaces local Morrey spaces
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