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斐波那契类LiNbO_3超晶格的二次谐波光双折射输出特性研究 被引量:1
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作者 杨湘波 邢达 刘有延 《量子电子学报》 CAS CSCD 北大核心 2002年第2期119-124,共6页
本文在简介了 FC(n)和按 FC(n)序列排列的 LiNbO3超晶格系统的结构特征之后,解析地推导了在小信号、平面波近似条件下,按 FC(n)序列排列的 LiNbO3超晶格系统二次谐波光的输出功率和转化效率公式,得出了 ... 本文在简介了 FC(n)和按 FC(n)序列排列的 LiNbO3超晶格系统的结构特征之后,解析地推导了在小信号、平面波近似条件下,按 FC(n)序列排列的 LiNbO3超晶格系统二次谐波光的输出功率和转化效率公式,得出了 LiNbO3晶体材料的上述系统寻常光的二次谐波输出光每单位面积的输出功率 S(2ω)对于基频光波长的关系,发现对于 LiNbO3晶体材料而言,一定的铁电畴序列系统存在相应稳定调谐的寻常倍频光输出功率,在红外光区域存在四条转换效率很大的调谐谱线;非寻常倍频光也具有相似的结论,但调谐谱线的波长向可见光区域发生偏移而且转化效率较高的谱线有六条.另外,还讨论了上述铁电畴系统的二次谐波输出光谱线的两种有趣的缺级效应. 展开更多
关键词 二次谐波 双折射 斐波那契类 LINBO3 输出特性 晶格系统
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BaFBr:Eu^(2+)的F心研究及一种能量最小优化方法的应用
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作者 赵兴华 吕玉鹏 陈凌孚 《南京师大学报(自然科学版)》 CAS CSCD 2002年第4期49-52,56,共5页
 根据Hartree Fork近似基础上的扩展离子处理方法研究BaFX:Eu2+中的缺陷问题,并且对晶格系统总能量进行能量最小优化,模拟PSL现象,得到了与实验值符合的结果,从而导出F心的吸收谱的产生机制.因此,此种能量最小优化方法可用于类似问题.
关键词 磷光体材料 BAFBR:EU^2+ F心 缺陷 能量最小优化方法 晶格系统 吸收谱 基态 激发态
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A.W.内希和他的“场论”建筑
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作者 胡戎叡 《新建筑》 1989年第3期56-61,79,共7页
SOM事务所是大家很熟悉的事务所,在该事务所中,有一位非常活跃的成员,他以其出色的成就,将其名字与SOM紧密联系在一起。他就是安德烈·沃尔特·内希(Andrew Walter Netsch)。内希是美国人,1920年2月23日出生于芝加哥。1939~194... SOM事务所是大家很熟悉的事务所,在该事务所中,有一位非常活跃的成员,他以其出色的成就,将其名字与SOM紧密联系在一起。他就是安德烈·沃尔特·内希(Andrew Walter Netsch)。内希是美国人,1920年2月23日出生于芝加哥。1939~1943年就读于麻省理工学院,获建筑学学士学位。战时曾参加美国军队工程部的工作,直到战后的1946年才离开。 展开更多
关键词 A.W 学士学位 安德烈 美国军队 晶格系统 美国海军 WALTER 设计过程 鱼眼镜头 诺州
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Superlattice Patterns in Coupled Turing Systems 被引量:1
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作者 刘富成 贺亚峰 潘宇扬 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第5期971-976,共6页
In this paper, superlattice patterns have been investigated by using a two linearly coupled Brusselator model. It is found that superlattice patterns can only be induced in the sub-system with the short wavelength. Th... In this paper, superlattice patterns have been investigated by using a two linearly coupled Brusselator model. It is found that superlattice patterns can only be induced in the sub-system with the short wavelength. Three different coupling methods have been used in order to investigate the mode interaction between the two Turing modes. It is proved in the simulations that interaction between activators in the two sub-systems leads to spontaneous formation of black eye pattern and/or white eye patterns while interaction between inhibitors leads to spontaneous formation of super-hexagonal pattern. It is also demonstrated that the same symmetries of the two modes and suitable wavelength ratio of the two modes should also be satisfied to form superlattice patterns. 展开更多
关键词 superlattice pattern turing instability mode interaction
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Magnetic Properties of a Mixed Spin-2 and Spin-5/2 Heisenberg Ferrimagnetic System on a Two-Dimensional Honeycomb Lattice: Green's Function Approach 被引量:3
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作者 YAO Kai-Lun LI Jian-Wen +2 位作者 LIU Zu-Li FU Hua-Hua ZU Lin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第4期741-746,共6页
The multisublattice Green's function technique is applied to study the magnetic properties of a mixed spin-2 and spin-5/2 Heisenberg ferrimagnetic system on a two-dimensional honeycomb lattice. The role of the differ... The multisublattice Green's function technique is applied to study the magnetic properties of a mixed spin-2 and spin-5/2 Heisenberg ferrimagnetic system on a two-dimensional honeycomb lattice. The role of the different interactions in the Hamiltonian is explored. When only the nearest-neighbor interaction and the single-ion anisotropy are included, our results indicate that there are compensation points at finite temperatures. When the next-nearest-neighbor interaction exceeds a minimum value that depends on the other parameters in the Hamiltonian, the compensation point disappears. The next-nearest-neighbor interaction has the effect of changing the compensation temperature. 展开更多
关键词 Heisenberg ferrimagnetic Green function spin-wave spectra MAGNETIZATION critical temperature compensation temperature
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First-principles lattice stability of Fe, Ru and Os 被引量:1
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作者 陶辉锦 尹健 《Journal of Central South University》 SCIE EI CAS 2009年第2期177-183,共7页
Lattice constants, total energies and densities of states of transition metals Fe, Ru and Os with BCC, FCC and HCP structures were calculated by the GGA+PBE functional and the ultrasoft pseudo-potential plane wave met... Lattice constants, total energies and densities of states of transition metals Fe, Ru and Os with BCC, FCC and HCP structures were calculated by the GGA+PBE functional and the ultrasoft pseudo-potential plane wave method, and compared with those of the first-principles projector augmented wave (PAW) method, CALPHAD method and experimental data. The results show that the lattice stability of this work is △GBCC-HCP>△GFCC-HCP>0, agreeing well with those of PAW method in the first-principles and CALPHAD method except for BCC-Fe. And the densities of state of HCP-Ru and Os have an obvious character of stable phase, agreeing completely with the results of the total energy calculations. Further analyses of atomic population show that the transition rate of electrons from s to p state for HCP, FCC and BCC crystals increases from Fe to Os, and a stronger cohesion, a higher cohesive energy or a more stable lattice between atoms of heavier metals are formed. 展开更多
关键词 FE RU OS lattice stability FIRST-PRINCIPLES
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Hierarchy of Combined TL-RTL Equations and an Associated (2+l)-Dimensional Lattice Equation 被引量:1
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作者 JIANG Qiao-Yun ZHOU Ru-Guang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第5X期773-778,共6页
A new (29-1)-dimensional lattice equation is presented based upon the first two members in the hierarchy of the combined Toda lattice and relativistic Toda lattice (TL-RTL) equations in (19991) dimensions. A Dar... A new (29-1)-dimensional lattice equation is presented based upon the first two members in the hierarchy of the combined Toda lattice and relativistic Toda lattice (TL-RTL) equations in (19991) dimensions. A Darboux transformation for the hierarchy of the combined TL-RTL equations is constructed. Solutions of the first two members in the hierarchy of the combined TL-RTL equations, as well as the new (29-1)-dimensional lattice equation are explicitly obtained by the Darboux transformation. 展开更多
关键词 combined TL-RTL equation integrable system Darboux transformation Toda lattice equation relativistic Toda lattice equation
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(2+2)-Dimensional Discrete Soliton Equations and Integrable Coupling System
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作者 于发军 李丽 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第5期793-798,共6页
In this paper, we extend a (2+2)-dimensional continuous zero curvature equation to (2+2)-dimensional discrete zero curvature equation, then a new (2+2)-dimensional cubic Volterra lattice hierarchy is obtained... In this paper, we extend a (2+2)-dimensional continuous zero curvature equation to (2+2)-dimensional discrete zero curvature equation, then a new (2+2)-dimensional cubic Volterra lattice hierarchy is obtained. Fhrthermore, the integrable coupling systems of the (2+2)-dimensional cubic Volterra lattice hierarchy and the generalized Toda lattice soliton equations are presented by using a Lie algebraic system sl(4). 展开更多
关键词 discrete soliton hierarchy integrable couplings generalized Toda equation cubic Volterra lattice equation
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(GaAs)_1(AlAs)_1(001)超晶格电子结构的从头计算 被引量:5
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作者 王仁智 黄美纯 《物理学报》 SCIE EI CAS CSCD 北大核心 1990年第7期1135-1142,共8页
本文用密度泛函线性丸盒轨道原子球近似方法(DFT-LMTO-ASA)对(GaAs)_1(AlAs)_1(001)超晶格的电子结构进行了第一原理性计算。利用Lowdin微扰法在矩阵元中计入d态的影响,可使本文方法仅用阶数很小(32×32)的久期方程便可较满意地处... 本文用密度泛函线性丸盒轨道原子球近似方法(DFT-LMTO-ASA)对(GaAs)_1(AlAs)_1(001)超晶格的电子结构进行了第一原理性计算。利用Lowdin微扰法在矩阵元中计入d态的影响,可使本文方法仅用阶数很小(32×32)的久期方程便可较满意地处理这个超晶格系统。计算并讨论了该超晶格的带隙,导带极小值处各本征态的分波特性以及GaAs和AlAs层间的价电子转移。我们的结果同最近用计算量大得多的从头算赝势法和完整势线性缀加平面波(FLAPW)法所得的结果进行了比较。结果表明,本文方法不仅具有合理的精度,而且有快速高效率的特点,更适于研究层数较多或结构更复杂的半导体超晶格,如(GaAs)m(AlAs)n等系统的电子结构性质。 展开更多
关键词 晶格系统 电子结构 从头计算
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Application of Homotopy Analysis Method to Solve Relativistic Toda Lattice System
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作者 王琪 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第6期1111-1116,共6页
In this letter, the homotopy analysis method is successfully applied to solve the Relativistic Toda lattice system. Comparisons are made between the results of the proposed method and exact solutions. Analysis results... In this letter, the homotopy analysis method is successfully applied to solve the Relativistic Toda lattice system. Comparisons are made between the results of the proposed method and exact solutions. Analysis results show that homotopy analysis method is a powerful and easy-to-use analytic tool to solve systems of differential-difference equations. 展开更多
关键词 Jhomotopy analysis method relativistic Toda lattice system
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Magnetic Properties of Transverse Ising Model under a Time Oscillating Longitudinal Field
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作者 石晓玲 王莉 魏国柱 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第4期715-718,共4页
A transverse Ising spin system, in the presence of time-dependent longitudinal field, is studied by the effective-field theory (EFT). The effective-field equations of motion of the average magnetization are given fo... A transverse Ising spin system, in the presence of time-dependent longitudinal field, is studied by the effective-field theory (EFT). The effective-field equations of motion of the average magnetization are given for the simple cubic lattice (Z ---- 6) and the honeycomb lattice (Z = 3). The Liapunov exponent A is calculated for discussing the stability of the magnetization and it is used to determine the phase boundary. The dynamic phase transition diagrams in ho/ZJ - F/ZJ plane and in ho/ZJ - T/ZJ plane have been drawn, and there is no dynamical tricritical point on the dynamic phase transition boundary. The effect of the thermal fluctuations upon the dynamic phase boundary has been discussed. 展开更多
关键词 effective-field theory transverse Ising model dynamic phase transition
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光电、光敏与发光材料
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《电子科技文摘》 2003年第5期10-11,共2页
0309292BaFBr:Eu<sup>2+</sup>的 F 心研究及一种能量最小优化方法的应用[刊]/赵兴华//南京师大学报(自然科学版).— 2002,25(4).—49~52,56(K)根据 Hartree-Fork 近似基础上的扩展离子处理方法研究BaFX:Eu<sup&g... 0309292BaFBr:Eu<sup>2+</sup>的 F 心研究及一种能量最小优化方法的应用[刊]/赵兴华//南京师大学报(自然科学版).— 2002,25(4).—49~52,56(K)根据 Hartree-Fork 近似基础上的扩展离子处理方法研究BaFX:Eu<sup>2+</sup>中的缺陷问题,并且对晶格系统总能量进行能量最小优化,模拟 PSL 现象,得到了与实验值符合的结果.从而导出 F 心的吸收谱的产生机制。因此,此种能量最小优化方法可用于类似问题。 展开更多
关键词 发光材料 晶格系统 处理方法研究 HARTREE 南京师大学报 吸收谱 发光学报 长余辉材料 缺陷问题 粉末粒度
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A systematic analysis of good matching sites between two lattices 被引量:1
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作者 YANG XiaoPeng ZHANG WenZheng 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第5期1343-1352,共10页
The geometrical matching/mismatching of lattices overlapped in 1, 2 and 3 dimensions have been analyzed systematically by variation of lattice misfit in a large range, far beyond the limits for semicoherent interfaces... The geometrical matching/mismatching of lattices overlapped in 1, 2 and 3 dimensions have been analyzed systematically by variation of lattice misfit in a large range, far beyond the limits for semicoherent interfaces. In order to evaluate the degree of matching, the density of good matching site (GMS) between two lattices is calculated. The analysis shows that the GMS density remains approximately constant, irrespectively to the degree of lattice misfit. This constant, defined as the average GMS density, decreases exponentially with the increasing dimension of misfit. Typically, for 6 = 15%, the average GMS densities are approximately 30%, 7%, and 1.4% for 1D, 2D, and 3D lattice misfits, respectively. The GMS density deviates significantly if a CSL of small X can be defined. The relationship between the GMS distribution and O-lattice is investigated. It indicates that an abrupt increase in the GMS density in an interface parallel to a principal O-lattice plane is equivalent to a reduction of dimension of misfit. This shows the agreement between the selections of principal O-lattice planes as candidates of the preferred interfaces and the condition that interfaces with high GMS density are preferred. 展开更多
关键词 good matching sites (GMS) O-lattice near-coincidence sites (NCS) structure ledge coincidence site lattice (CSL)
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A New Generalized System on the Two-Dimensional Toda Lattice and Its Reduction
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作者 朱国庆 王红艳 《Communications in Theoretical Physics》 SCIE CAS CSCD 2013年第2期137-140,共4页
In this paper, we apply the source generation procedure to the coupled 2D Toda lattice equation (also called Pfaffianized 2D Toda lattice), then we get a more generalized system which is the coupled 2D Toda lattice ... In this paper, we apply the source generation procedure to the coupled 2D Toda lattice equation (also called Pfaffianized 2D Toda lattice), then we get a more generalized system which is the coupled 2D Toda lattice with self-consistent sources (p-2D TodaESCS), and a pfaman type solution of the new system is given. Consequently, by using the reduction of the pfaffian solution to the determinant form, this new system can not only be reduced to the 2D TodaESCS, but be reduced to the coupled 2D Toda lattice equation. This result indicates that the p-2D TodaESCS is also a pfafilan version of the 2D TodaESCS, which implies the commutativity between the source generation procedure and Pfaffianization is valid to the semi-discrete soliton equation. 展开更多
关键词 2D Toda lattice equation source generation procedure PFAFFIANIZATION
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Bose-Einstein Condensates in Optical Lattices with Higher-Order Interactions
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作者 张爱霞 薛具奎 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第4期595-602,共8页
The higher-order interactions of Bose-Einstein condensate in multi-dimensional optical lattices are discussed both analytically and numerically.It is demonstrated that the effects of the higher-order atomic interactio... The higher-order interactions of Bose-Einstein condensate in multi-dimensional optical lattices are discussed both analytically and numerically.It is demonstrated that the effects of the higher-order atomic interactions on the sound speed and the stabilities of Bloch waves strongly depend on the lattice strength.In the presence of higher-order effects,tighter and high-dimensional lattices are confirmed to be two positive factors for maintaining the system's energetic stability,and the dynamical instability of Bloch waves can take place simultaneously with the energetic instability.In addition,we find that the higher-order interactions exhibit a long-range behavior and the long-lived coherent Bloch oscillations in a tilted optical lattice exist.Our results provide an effective way to probe the higher-order interactions in optical lattices. 展开更多
关键词 Bose-Einstein condensates optical lattices higher-order interactions
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