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Diffraction of plane P waves by a canyon of arbitrary shape in poroelastic half-space (Ⅰ): Formulation 被引量:10
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作者 Jianwen Liang Zhongxian Liu 《Earthquake Science》 CSCD 2009年第3期215-222,共8页
This paper presents an indirect boundary integration equation method for diffraction of plane P waves by a two-dimensional canyon of arbitrary shape in poroelastic half-space. The Green's functions of compressional a... This paper presents an indirect boundary integration equation method for diffraction of plane P waves by a two-dimensional canyon of arbitrary shape in poroelastic half-space. The Green's functions of compressional and shear wave sources in poroelastic half-space are derived based on Biot's theory. The scattered waves are constructed using the fictitious wave sources close to the boundary of the canyon, and magnitude of the fictitious wave sources are determined by the boundary conditions. The precision of the method is verified by the satisfaction extent of boundary conditions, the comparison between the degenerated solutions of single-phased half-space and the well-known solutions, and the numerical stability of the method. 展开更多
关键词 poroelastic half-space CANYON DIFFRACTION plane P wave compressional wave source shear wave source Green's function
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Diffraction of plane SV waves by a cavity in poroelastic half-space 被引量:15
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作者 Liang Jianwen and Liu Zhongxian Department of Civil Engineering, Tianjin University, Tianjin 300072, China Professor PhD Candidate 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2009年第1期29-46,共18页
This paper presents an indirect boundary integration equation method for diffraction of plane SV waves by a 2-D cavity in a poroelastic half-space.The Green's functions of compressive and shear wave sources are deriv... This paper presents an indirect boundary integration equation method for diffraction of plane SV waves by a 2-D cavity in a poroelastic half-space.The Green's functions of compressive and shear wave sources are derived based on Biot's theory. The scattered waves are constructed using fictitious wave sources close to the boundary of the cavity, and their magnitudes are determined by the boundary conditions. Verification of the accuracy is performed by: (1) checking the satisfaction extent of the boundary conditions, (2) comparing the degenerated solutions of a single-phased case with well- known solutions, and (3) examining the numerical stability of the solutions. The nature of diffraction of plane SV waves around a cavity in a poroelastic half-space is investigated by numerical examples. 展开更多
关键词 poroelastic half-space CAVITY DIFFRACTION plane SV waves compressive wave source shear wave source Green's function pore pressure
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Surface motion of a semi-elliptical hill for incident plane SH waves 被引量:9
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作者 Jianwen Liang Jia Fu 《Earthquake Science》 CSCD 2011年第5期447-462,共16页
A closed-form analytical solution of surface motion of a semi-elliptical cylindrical hill for incident plane SH waves is presented. Although some previous analytical work had already dealt with hill topography of semi... A closed-form analytical solution of surface motion of a semi-elliptical cylindrical hill for incident plane SH waves is presented. Although some previous analytical work had already dealt with hill topography of semi-circular and shallow circular, our work aims at calculating surface motion of very prolate hill for high incident frequency, and explaining the special vibrating is checked by boundary conditions, numerical results for and some conclusions are obtained. properties of very prolate hill. Accuracy of the solution surface motion of oblate and prolate hills are calculated, 展开更多
关键词 semi-elliptical hill analytical solution plane SH wave surface motion oblate hill prolate hill Mathieu function high frequency
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Assignment of terahertz vibrational modes of L-glutamine using density functional theory within generalized-gradient approximation 被引量:7
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作者 张寒 张朝晖 +3 位作者 赵小燕 张天尧 燕芳 申江 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第7期211-218,共8页
The crystal structure of L-glutamine is stabilized by a three-dimensional network of intermolecular hydrogen bonds.We utilize plane-wave density functional theory lattice-dynamics calculations within the generalized-g... The crystal structure of L-glutamine is stabilized by a three-dimensional network of intermolecular hydrogen bonds.We utilize plane-wave density functional theory lattice-dynamics calculations within the generalized-gradient approximation(GGA), Perdew–Burke–Ernzerhof(PBE), PBE for solids(PBEsol), PBE with Wu–Cohen exchange(WC), and dispersion-corrected PBE, to investigate the effect of these intermolecular contacts on the absorption spectra of glutamine in the terahertz frequency range. Among these calculations, the solid-state simulated results obtained using the WC method exhibit a good agreement with the measured absorption spectra, and the absorption features are assigned with the help of WC. This indicates that the vibrational modes of glutamine were related to the combination of intramolecular and intermolecular motions, the intramolecular modes were dominated by rocking or torsion involving functional groups; the intermolecular modes mainly result from the translational motions of individual molecules, and the rocking of the hydrogenbonded functional groups. 展开更多
关键词 terahertz vibrational modes amino acid plane-wave density functional theory generalized-gradient approximation
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The features of band structures for woodpile three-dimensional photonic crystals with plasma and function dielectric constituents
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作者 Haifeng ZHANG Hao ZHANG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2018年第10期51-61,共11页
The features of the band structures of woodpile three-dimensional (3D) photonic crystals composed of plasma and function dielectric constituents, referred to as function plasma photonic crystals (FPPCs), are theor... The features of the band structures of woodpile three-dimensional (3D) photonic crystals composed of plasma and function dielectric constituents, referred to as function plasma photonic crystals (FPPCs), are theoretically studied by a modified plane wave expansion method, and the formulas for computing the band structures are derived. The arrangement for the proposed FPPCs is that the function dielectric columns are surrounded by plasma, and the embedded dielectric columns are stacked according to the woodpile lattices, which are arrayed with facecentered-tetragonal symmetry. The relative permittivity of function dielectric rods depends on the function coefficient and space coordinates. The relationships between the parameters for inserted function dielectric rods and plasma and the band structures are also investigated. The computed results illustrate that the obtained PBG can be tuned by those parameters as mentioned above. Compared to dielectric-air PCs, function dielectric PCs and plasma dielectric PCs with the same topology, a wider bandwidth of the photonic band gap can be observed in the proposed FPPCs. The calculated results also show us another alternative way to realize reconfigurable applications with 3D FPPCs. 展开更多
关键词 plasma photonic crystals function dielectric photonic band gaps plane wave expansion method
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Comment on “Band gaps structure and semi-Dirac point of two-dimensional function photonic crystals” by Si-Qi Zhang et al.
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作者 章海锋 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第1期618-622,共5页
Recently, Zhang et al. (Chin. Phys. B 26 024208 (2017)) investigated the band gap structures and semi-Dirac point of two-dimensional function photonic crystals, and the equations for the plane wave expansion metho... Recently, Zhang et al. (Chin. Phys. B 26 024208 (2017)) investigated the band gap structures and semi-Dirac point of two-dimensional function photonic crystals, and the equations for the plane wave expansion method were induced to obtain the band structures. That report shows the band diagrams with the effects of function coefficient k and medium column ra under TE and TM waves. The proposed results look correct at first glance, but the authors made some mistakes in their report. Thus, the calculated results in their paper are incorrect. According to our calculations, the errors in their report are corrected, and the correct band structures also are presented in this paper. 展开更多
关键词 two-dimensional function photonic crystals photonic band gaps plane wave expansion method Monte Carlo method
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Reduction of Superconducting Wave Packets in Dispersion Dynamics
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作者 Antony J. Bourdillon 《Journal of Modern Physics》 2020年第3期365-377,共13页
Two problems in solid state physics and superconductivity are addressed by applications of dispersion dynamics. The first is the Hall effect. The dynamics of charges that yield positive Hall coefficients in material h... Two problems in solid state physics and superconductivity are addressed by applications of dispersion dynamics. The first is the Hall effect. The dynamics of charges that yield positive Hall coefficients in material having no mobile positive charges have always been problematic The effect requires both electric and magnetic response, but magnetic deflection is only possible in mobile charges. In high temperature superconductors, these charges must be electrons. Contrary to Newton’s second law, their acceleration is reversed in crystal fields that dictate negative dispersion. This is evident in room temperature measurements, but a second problem arises in supercurrents at low temperatures. The charge dynamics in material having zero internal electric field because of zero resistivity;and zero magnetic field because of the Meissner-Ochsenfeld diamagnetism;while the supercurrents themselves have properties of zero net momentum;zero spin;and sometimes, zero charge;are so far from having been resolved that they may never have been addressed. Again, dispersion dynamics are developed to provide solutions given by reduction of the superconducting wave packet. The reduction is here physically analyzed, though it is usually treated as a quantized unobservable. 展开更多
关键词 REDUCTION wave Packet Dispersion Dynamics Special RELATIVITY Propagation TRANSVERSE plane functions of RELATIVISTIC Free Particles QUANTUM Physics QUANTUM Mechanics
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Dispersion Dynamical Magnetic Radius in Intrinsic Spin Equals the Compton Wavelength
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作者 Antony J. Bourdillon 《Journal of Modern Physics》 2018年第13期2295-2307,共13页
Because magnetic moment is spatial in classical magnetostatics, we progress beyond the axiomatic concept of the point particle electron in physics. Orbital magnetic moment is well grounded in spherical harmonics in a ... Because magnetic moment is spatial in classical magnetostatics, we progress beyond the axiomatic concept of the point particle electron in physics. Orbital magnetic moment is well grounded in spherical harmonics in a central field. There, quantum numbers are integral. The half-integral spinor moment appears to be due to cylindrical motion in an external applied magnetic field;when this is zero , the spin states are degenerate. Consider lifting the degeneracy by diamagnetism in the cylindrical magnetic field: a uniquely derived electronic magnetic radius shares the identical value to the Compton wavelength. 展开更多
关键词 Magnetic RADIUS INTRINSIC SPIN COMPTON waveLENGTH DISPERSION Dynamics Stable wave Packet Special Relativity Propagation Transverse plane functions of Relativistic Free Particles Quantum Physics Quantum Mechanics
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反平面线源荷载作用下浅埋圆形非完全粘结隧道动力响应研究
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作者 李志文 李潜 +2 位作者 徐斌 李晓锋 李海波 《爆炸与冲击》 EI CAS CSCD 北大核心 2024年第8期60-71,共12页
为加深理解波源距离和非完全粘结对地震波散射的影响规律,结合位移不连续模型、波函数展开法、Graf公式和镜像方法推导了反平面线源荷载下浅埋圆形非完全粘结隧道动力响应的级数解,并通过衬砌内外边界条件残余量与级数解截断项数的关系... 为加深理解波源距离和非完全粘结对地震波散射的影响规律,结合位移不连续模型、波函数展开法、Graf公式和镜像方法推导了反平面线源荷载下浅埋圆形非完全粘结隧道动力响应的级数解,并通过衬砌内外边界条件残余量与级数解截断项数的关系校验了该解的精度。通过对该级数解进行参数分析,系统地探讨了衬砌与围岩的接触刚度、衬砌模量、衬砌厚度、隧道埋深和波源距离等因素对衬砌内表面位移和周向剪应力的影响。结果表明:衬砌与围岩的接触刚度对隧道的动力响应具有显著的影响,尤其在某些较小接触刚度情况下隧道动力响应幅值可能非常大;增大衬砌模量会减小位移,但同时会导致周向剪应力增加;增大衬砌厚度能同时减小位移和周向剪应力;增大隧道埋深会使最大位移和周向剪应力向隧道拱顶附近移动;增大线源与隧道的水平距离会使隧道背波侧相对幅值增大。 展开更多
关键词 浅埋隧道 地震波散射 反平面线源 波函数展开法
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水平界面上方球体的电磁散射
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作者 张华永 陈珍珍 《电波科学学报》 CSCD 北大核心 2024年第6期1120-1124,共5页
研究水平界面上方球体的电磁散射可以为诸多应用提供一个合适的理论模型,为此本文提出了一种精确求解此电磁散射问题的半解析方法。该方法应用适当的球矢量波函数来展开球体的散射场和内场,并且考虑到球体与水平界面之间的耦合散射,应... 研究水平界面上方球体的电磁散射可以为诸多应用提供一个合适的理论模型,为此本文提出了一种精确求解此电磁散射问题的半解析方法。该方法应用适当的球矢量波函数来展开球体的散射场和内场,并且考虑到球体与水平界面之间的耦合散射,应用了球和圆柱矢量波函数之间的转换关系。水平界面对入射电磁波的反射场和球体的散射场均采用投影法计算。以平面波、高斯波束和拉盖尔-高斯波束照射硅基底上方的聚苯乙烯球为例,计算了归一化的微分散射截面。数值结果表明对于入射的平面波和高斯波束在反射波方向附近散射最强,另外随着球体离水平界面距离的增加而前向散射变大。 展开更多
关键词 水平界面上方球体 电磁散射 矢量波函数 投影法 微分散射截面
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含裂纹声子晶体能带分析的改进局部径向基函数配点法
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作者 徐杰 郑辉 +2 位作者 石承志 闫雪豹 文丕华 《力学学报》 EI CAS CSCD 北大核心 2024年第7期2063-2076,共14页
基于直接法局部径向基函数配点法(local radial basis function collocation method,LRBFCM)提出了含裂纹声子晶体反平面弹性波的能带结构计算方法,分析了其能带结构特性,并通过有限元法计算对比验证该数值结果的准确性和有效性.在边界... 基于直接法局部径向基函数配点法(local radial basis function collocation method,LRBFCM)提出了含裂纹声子晶体反平面弹性波的能带结构计算方法,分析了其能带结构特性,并通过有限元法计算对比验证该数值结果的准确性和有效性.在边界上采用直接法沿方向取局部节点,解决了边界求解不稳定问题,讨论了数值方法的处理技巧对结果的影响.并通过考虑不同声阻抗比、散射体形状(方形、圆形)和裂纹情况,验证了该方法计算含裂纹声子晶体能带结构的适用性.研究了形状参数、配点数对计算结果的影响.最后深入分析了不同长度和位置的裂纹对声子晶体能带结构的影响特性,并进行了对比分析.文章的创新性在于用直接法局部径向基函数配点法解决了含裂纹声子晶体能带结构计算的问题,极大增加了声子晶体的应用价值.研究结果显示:随着裂纹的扩展,能带结构带隙逐渐变窄;当裂纹扩展到一定程度时,金散射体的声子晶体带隙数量会增加,且新增带隙会随着裂纹扩展而变宽,但铝散射体的声子晶体带隙数量会减少;直接法局部径向基函数配点法可以大大提高含裂纹声子晶体能带结构的计算效率和计算精度. 展开更多
关键词 径向基函数 反平面弹性波 应力强度因子 裂纹 有限元法
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混响室内模拟多径衰落场环境的概率统计模型
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作者 陈佳豪 赵翔 +1 位作者 闫丽萍 刘长军 《安全与电磁兼容》 2024年第1期66-71,共6页
已有混响室概率统计模型不能同时模拟多种多径衰落场环境。通过扩展经典混响室平面波叠加模型,建立了更具普适性的混响室内模拟多径衰落场环境的概率统计模型。推导了电场直角分量模值的概率密度函数(PDF),在理论上验证了新模型能同时... 已有混响室概率统计模型不能同时模拟多种多径衰落场环境。通过扩展经典混响室平面波叠加模型,建立了更具普适性的混响室内模拟多径衰落场环境的概率统计模型。推导了电场直角分量模值的概率密度函数(PDF),在理论上验证了新模型能同时模拟瑞利分布、莱斯分布及更多多径衰落场环境。通过蒙特卡洛模拟仿真了电场直角分量模值的PDF,并与理论PDF对比,进一步验证了新模型同时模拟多种多径衰落场环境的能力。 展开更多
关键词 混响室 平面波叠加 多径衰落 概率密度函数 蒙特卡洛模拟
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求解近场散射问题的最小二乘方法 被引量:8
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作者 栾天 王玉洁 郑恩希 《吉林大学学报(理学版)》 CAS CSCD 北大核心 2013年第5期811-814,共4页
应用最小二乘方法数值求解全内反射显微镜模型对应的时谐散射问题.先利用平面波函数和倏逝波函数构造试探函数空间,再利用解及其法向导数在单元内边界处的跃度和外边界条件定义目标泛函.结果表明,该方法简单易行,所需剖分单元少,算法精... 应用最小二乘方法数值求解全内反射显微镜模型对应的时谐散射问题.先利用平面波函数和倏逝波函数构造试探函数空间,再利用解及其法向导数在单元内边界处的跃度和外边界条件定义目标泛函.结果表明,该方法简单易行,所需剖分单元少,算法精度高.数值实验验证了算法的有效性. 展开更多
关键词 HELMHOLTZ方程 最小二乘方法 平面波函数
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Fourier变换重建超声图像的研究 被引量:8
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作者 彭虎 陆建宇 +1 位作者 冯焕清 张作生 《中国科学技术大学学报》 CAS CSCD 北大核心 2003年第5期619-624,共6页
基于有限衍射波理论的高帧率 (highframerate,HFR)超声成像系统是通过发射平面波成像的 .由于采用平面波 ,故成像区域为矩形 .为了得到扇形成像 ,提出了一种更一般化的Fourier重建图像的方法 ,它同样基于一次发射就可重建超声图像 .与原... 基于有限衍射波理论的高帧率 (highframerate,HFR)超声成像系统是通过发射平面波成像的 .由于采用平面波 ,故成像区域为矩形 .为了得到扇形成像 ,提出了一种更一般化的Fourier重建图像的方法 ,它同样基于一次发射就可重建超声图像 .与原HFR方法不同的是发射声场可以是非平面波 .在非平面波声场中进行了计算机仿真 .由于采用了由零阶汉克尔函数所定义的圆柱场 ,获得了具有扇形形状的超声图像 ,仿真结果显示了新方法的有效和更具有一般性的特点 . 展开更多
关键词 高帧率 平面波 汉克尔函数
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光栅衍射问题数值计算的最小二乘方法 被引量:6
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作者 栾天 王玉洁 郑恩希 《吉林大学学报(理学版)》 CAS CSCD 北大核心 2013年第6期1037-1040,共4页
针对光栅衍射问题提出一种最小二乘算法.在计算区域简单剖分的基础上,选取平面波函数近似解的局部性态,并利用Rayleigh展开的有限项截断近似解在无穷远处的性态.结果表明,该方法适用于一般形状的衍射光栅和大波数情形,应用过程简单,所... 针对光栅衍射问题提出一种最小二乘算法.在计算区域简单剖分的基础上,选取平面波函数近似解的局部性态,并利用Rayleigh展开的有限项截断近似解在无穷远处的性态.结果表明,该方法适用于一般形状的衍射光栅和大波数情形,应用过程简单,所需剖分单元少,收敛速度快.数值实验验证了算法的有效性. 展开更多
关键词 光栅衍射 Rayleigh展开 平面波函数
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如何“写”出平面简谐波的波函数 被引量:8
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作者 杨百愚 冯大毅 +2 位作者 张崇辉 冯明德 马华 《物理与工程》 2008年第5期9-12,共4页
介绍了大学物理课堂中讲授平面简谐波波函数的一种教学设计,其核心是在课堂教学中归纳总结出平面简谐波波函数的一般形式,为学生提供处理波函数问题的简单方法,该方法只要给定任意点的振动方程及波的传播方向,就可依据一般形式"写&... 介绍了大学物理课堂中讲授平面简谐波波函数的一种教学设计,其核心是在课堂教学中归纳总结出平面简谐波波函数的一般形式,为学生提供处理波函数问题的简单方法,该方法只要给定任意点的振动方程及波的传播方向,就可依据一般形式"写"出平面简谐波的波函数. 展开更多
关键词 平面简谐波 波函数 振动方程
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LaNi_(4.75)Al_(0.25)储氢材料的密度泛函理论研究 被引量:3
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作者 陈东 高涛 +1 位作者 齐新华 朱正和 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2006年第9期1383-1387,共5页
在全电子水平上,基于广义梯度近似(GGA)密度泛函和全势能线性缀加平面波方法(FLAPW),研究了LaNi4.75Al0.25的晶体结构。采用GGAPerdew96交换相关泛函,计算给出了LaNi4.75Al0.25的晶胞参数为a=b=0.5033nm、c=0.4018nm、a/c=1.252,Al原子... 在全电子水平上,基于广义梯度近似(GGA)密度泛函和全势能线性缀加平面波方法(FLAPW),研究了LaNi4.75Al0.25的晶体结构。采用GGAPerdew96交换相关泛函,计算给出了LaNi4.75Al0.25的晶胞参数为a=b=0.5033nm、c=0.4018nm、a/c=1.252,Al原子最可能占据的3g格位的等效位置(0.75,0,0.5),计算还给出了合金的能带结构、态密度(DOS)和电荷密度图,计算结果与实验值符合得相当好。 展开更多
关键词 LaNi4.75Al0.25 全势能线性缀加平面波方法(FLAPW) 密度泛函
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求解开腔体时谐散射问题的数值算法 被引量:6
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作者 栾天 谭希丽 李庆春 《吉林大学学报(理学版)》 CAS CSCD 北大核心 2015年第1期37-40,共4页
针对一类开腔体时谐散射问题提出一种有效的数值算法.该算法先对计算区域进行简单剖分,再利用Fourier-Bessel函数和平面波函数去近似解的局部性态,并利用散射场的多极展开式逼近解在无穷远处的性态;然后借助最小二乘算法迫使数值解在子... 针对一类开腔体时谐散射问题提出一种有效的数值算法.该算法先对计算区域进行简单剖分,再利用Fourier-Bessel函数和平面波函数去近似解的局部性态,并利用散射场的多极展开式逼近解在无穷远处的性态;然后借助最小二乘算法迫使数值解在子区域内边界处近似满足连续性条件.数值模拟验证了算法的有效性. 展开更多
关键词 HELMHOLTZ方程 Fourier-Bessel函数 平面波 多极展开式
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近场散射问题数值计算的超弱变分方法 被引量:2
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作者 栾天 刘明辉 《吉林大学学报(理学版)》 CAS CSCD 北大核心 2014年第1期39-44,共6页
针对以全内反射显微镜为模型的近场散射问题提出一种超弱变分方法.在计算区域网格剖分的基础上,利用Green公式将问题转化到网格边界上求解,并利用平面波函数和倏逝波函数逼近解的局部性态.结果表明,算法能有效数值模拟近场散射问题,适... 针对以全内反射显微镜为模型的近场散射问题提出一种超弱变分方法.在计算区域网格剖分的基础上,利用Green公式将问题转化到网格边界上求解,并利用平面波函数和倏逝波函数逼近解的局部性态.结果表明,算法能有效数值模拟近场散射问题,适用于大波数情形,收敛速度快. 展开更多
关键词 超弱变分方法 平面波函数 倏逝波函数
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带罩导弹远场方向图数值仿真中积分域的确定 被引量:2
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作者 戎华 王晓明 +2 位作者 郭东明 宣兆成 王伟 《电子与信息学报》 EI CSCD 北大核心 2002年第9期1245-1250,共6页
导弹天线罩是用来保护位于高速飞行的导弹前端的天线系统免受外界影响的一种装置,为研究导弹天线罩对天线性能所造成的影响,该文在运用平面波谱-表面积分法分析天线罩综合电性能基础上,详细讨论了为获取带罩导弹远场辐射方向图所采用的... 导弹天线罩是用来保护位于高速飞行的导弹前端的天线系统免受外界影响的一种装置,为研究导弹天线罩对天线性能所造成的影响,该文在运用平面波谱-表面积分法分析天线罩综合电性能基础上,详细讨论了为获取带罩导弹远场辐射方向图所采用的数值算法中的积分区域的确定。 展开更多
关键词 导弹 远场方向图 数值仿真 积分域 天线罩 样条函数 平面波谱
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