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Slowly moving matter-wave gap soliton propagation in weak random nonlinear potential
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作者 张铭锐 张永亮 +1 位作者 蒋寻涯 资剑 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第6期2160-2169,共10页
We systematically investigate the motion of slowly moving matter wave gap solitons in a nonlinear potential, produced by the weak random spatial variation of the atomic scattering length. With the weak randomness, we ... We systematically investigate the motion of slowly moving matter wave gap solitons in a nonlinear potential, produced by the weak random spatial variation of the atomic scattering length. With the weak randomness, we construct an effective-particle theory to study the motion of gap solitons. Based on the effective-particle theory, the effect of the randomness on gap solitons is obtained, and the motion of gap solitons is finally solved. Moreover, the analytic results for the general behaviours of gap soliton motion, such as the ensemble-average speed and the reflection probability depending on the weak randomness are obtained. We find that with the increase of the random strength the ensemble-average speed of gap solitons decreases slowly where the reduction is proportional to the variance of the weak randomness, and the reflection probability becomes larger. The theoretical results are in good agreement with the numerical simulations based on the Cross-Pitaevskii equation. 展开更多
关键词 gap soliton weak random nonlinear potentials effective particle picture
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Discrete gap breathers in a diatomic K2-K3-K4 chain with cubic nonlinearity
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作者 田强 李宓善 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第1期228-235,共8页
The discrete gap breathers (DGBs) in a one-dimensional diatomic chain with K2-K3-K4 potential are analysed. Using the local anharmonicity approximation, the analytical investigation has been implemented. The depende... The discrete gap breathers (DGBs) in a one-dimensional diatomic chain with K2-K3-K4 potential are analysed. Using the local anharmonicity approximation, the analytical investigation has been implemented. The dependence of the central amplitude of the discrete gap breathers on the breather frequency and the localization parameter are calculated. With increasing breather frequency, the DGB amplitudes decrease. As a function of the localization parameter, the central amplitude exhibits bistability, corresponding to the two branches of the curve ω = ω(ζ). With a nonzero cubic term, the HS mode of DGB profiles becomes weaker. With increasing K3, the HS mode of DGB profiles becomes weaker and a bit narrower. For the LS mode, with increasing K3, the central particle amplitude becomes larger, and the DGB profile becomes much sharper. But, as k3 increases further, the central particle amplitude of the LS mode becomes smaller. 展开更多
关键词 discrete gap breather diatomic chain cubic nonlinearity
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Vortex solitons in the semi-infinite gap of optically induced periodic lattices 被引量:4
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作者 王建东 纪红 刘普生 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第4期286-291,共6页
Vortex solitons with a ring vortex core residing in a single lattice site in the semi-infinite gap of square optical lattices are reported. These solitons are no longer bound states of the Bloch-wave unit (Bloch-wave... Vortex solitons with a ring vortex core residing in a single lattice site in the semi-infinite gap of square optical lattices are reported. These solitons are no longer bound states of the Bloch-wave unit (Bloch-wave distribution in one lattice site) at the band edge of the periodic lattice, and consequently they do not bifurcate from the corresponding band edge. For saturable nonlinearity, one family of such solitons is found, and its existing curve forms a closed loop, which is very surprising. For Kerr nonlinearity, two families of such vortex solitons are found. 展开更多
关键词 vortex soliton Bloch band gap nonlinear periodic lattice
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Numerical study of resonance induced by wave action on multiple rectangular boxes with narrow gaps 被引量:5
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作者 NING Dezhi SU Xiaojie +1 位作者 ZHAO Ming TENG Bin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2015年第5期92-102,共11页
By introducing a source term into the Laplace equation, a two-dimensional fully nonlinear time-domain numerical wave flume (NWF) is developed to investigate the resonance induced by the interaction between waves and... By introducing a source term into the Laplace equation, a two-dimensional fully nonlinear time-domain numerical wave flume (NWF) is developed to investigate the resonance induced by the interaction between waves and multiple objects with narrow gaps. In the numerical model, the fully nonlinear kinematic and dynamic boundary conditions are satisfied on the instantaneous free surface and the constant artificial damping is employed in the gaps to approximate the viscous dissipation due to vortex motion and flow separation. The computational domain is discretized using a higher-order boundary element method (HOBEM). The proposed model is firstly validated against the published experimental data and numerical results of the wave height in the narrow gap between two boxes, the wave heights in the two gaps of three boxes, and wave loads on the boxes. Then, the extensive numerical experiments are performed to study the influences of the number of the boxes and the gap spacing on the resonant frequency, reflected and transmitted wave heights and wave loads on the boxes. 展开更多
关键词 narrow gap RESONANCE higher-order boundary element nonlinear numerical wave flume
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Linear and nonlinear optical properties of Sb-doped GeSe_2 thin films
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作者 张振营 陈芬 +4 位作者 陆顺斌 王永辉 沈祥 戴世勋 聂秋华 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第6期483-487,共5页
Sb-doped GeSe2 chalcogenide thin films are prepared by the magnetron co-sputtering method. The linear optical properties of as-deposited films are derived by analyzing transmission spectra. The refractive index rises ... Sb-doped GeSe2 chalcogenide thin films are prepared by the magnetron co-sputtering method. The linear optical properties of as-deposited films are derived by analyzing transmission spectra. The refractive index rises and the optical band gap decreases from 2.08 eV to 1.41 eV with increasing the Sb content. X-ray photoelectron spectra further confirm the formation of a covalent Sb--Se bond. The third-order nonlinear optical properties of thin films are investigated under femtosecond laser excitation at 800 nm. The results show that the third-order nonlinear optical properties are enhanced with increasing the concentration of Sb. The nonlinear refraction indices of these thin films are measured to be on the order of 10-18 m2/W with a positive sign and the nonlinear absorption coefficients are obtained to be on the order of 10-10 m/W. These excellent properties indicate that Sb-doped Ge-Se films have a good prospect in the applications of nonlinear optical devices. 展开更多
关键词 chalcogenides films refractive index optical band gap nonlinear optical properties
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Nonlinear Optical Properties in Bi_2O_3-B_2O_3-SiO_2 Glasses
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作者 聂秋华 陈燕飞 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2007年第B12期806-808,共3页
A series of bismuth borate silica glasses were prepared and their densities, linear refractive indices and transmission spectra were measured. The optical gaps Eopt were obtained from the extrapolation of the linear p... A series of bismuth borate silica glasses were prepared and their densities, linear refractive indices and transmission spectra were measured. The optical gaps Eopt were obtained from the extrapolation of the linear portions to zero absorption. A decrease in the value of Eopt with increasing bismuth content may be explained by suggesting that the non-bridging oxygen ion content increases .It was found that high refractive index and narrow bandgap could lead into high third-order optical nonlinearity. 展开更多
关键词 optical band gap optical nonlinearity bismuth oxide
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Nonlinear Optical Properties in Bismuth-based Glasses
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作者 章健良 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2011年第1期61-64,共4页
A series of glasses with high Bi2O3 content of Bi2O3-B2O3-WO3 ternary system were chosen and prepared .Their densities and linear refractive indices increase with increasing WO3 content. The optical band gaps Eopt of ... A series of glasses with high Bi2O3 content of Bi2O3-B2O3-WO3 ternary system were chosen and prepared .Their densities and linear refractive indices increase with increasing WO3 content. The optical band gaps Eopt of glasses obtained from ultraviolet absorption edges decreases with increase of WO3 content. Z-scan technique was carried out to investigate the third-order nonlinear optical properties of the glasses. It is found that the nonlinear refraction γ increases with decreasing the optical band gap Eopt, since an increase of WO3 content can promote the non-bridging oxygen ion content, and the highest γ value of samples is 1.173×10-14 cm2/W. The results show that these glasses are potential materials in the application of third-order nonlinear optics field. 展开更多
关键词 bismuth glasses optical band gap third-order nonlinear Z-SCAN
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Surface defect gap solitons in two-dimensional optical lattices
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作者 孟云吉 刘友文 唐宇煌 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第7期314-319,共6页
We investigate the existence and stability of surface defect gap solitons at an interface between a defect in a two-dimensional optical lattice and a uniform saturable Kerr nonlinear medium. The surface defect embedde... We investigate the existence and stability of surface defect gap solitons at an interface between a defect in a two-dimensional optical lattice and a uniform saturable Kerr nonlinear medium. The surface defect embedded in the two-dimensional optical lattice gives rise to some unique properties. It is interestingly found that for the negative defect, stable surface defect gap solitons can exist both in the semi-infinite gap and in the first gap. The deeper the negative defect, the narrower the stable region in the semi-infinite gap will be. For a positive defect, the surface defect gap solitons exist only in the semi-infinite gap and the stable region localizes in a low power region. 展开更多
关键词 surface defect gap soliton optical lattice saturable Kerr nonlinear media
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Synthesis of Poly (3-acetylpyrrolyl methine) with Azobenzene Side Groups and Study on Its Third-order Nonlinear Optical Property 被引量:4
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作者 Zhigang ZHANG Hongcai WU +1 位作者 Lingjie MENG Wenhui YI 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第5期715-718,共4页
A novel soluble π-conjugated polymer, poly [(3-acetylpyrrole-2, 5-diyl) p-(N, N-dimethylamino) azobenzylidene] (PAPDMAABE), was synthesized by condensation of 3-acetylpyrrole with 4-aldehyde-4'-dimethylaminoaz... A novel soluble π-conjugated polymer, poly [(3-acetylpyrrole-2, 5-diyl) p-(N, N-dimethylamino) azobenzylidene] (PAPDMAABE), was synthesized by condensation of 3-acetylpyrrole with 4-aldehyde-4'-dimethylaminoazobenzene (ADMAA). The chemical structure of PAPDMAABE was characterized by Fourier transform infrared spectroscopy (FTIR), ^1H-NMR, and UV-Vis-NIR spectra. Transmission electron microscope (TEM) analysis for PAPDMAABE indicates that part of PAPDMAABE is in crystal state, due to the short-range order of the polymer. Thermogravimetric analysis (TGA) curve shows that the polymer has good thermal stability and its decomposition temperature is 248℃. The optical band gap of PAPDMAABE obtained from the optical absorption spectrum is about 1.73 eV. The resonant third-order nonlinear optical property of PAPDMAABE at 532 nm was studied using degenerate four-wave mixing (DFWM) technique. The resonant third-order nonlinear optical susceptibility of the polymer is about 7.48×10^-8 esu. 展开更多
关键词 Poly [(3-acetylpyrrole-2 5-diyl) p-(N N-dimethylamino) azobenzylidene] Small optical band gap Degenerate four-wave mixing Third-order nonlinear property
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Air Gap Prediction for Floating Bodies Using a 3D Numerical Wave Tank Approach 被引量:1
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作者 Shivaji Ganesan T. Debabrata Sen 《Journal of Marine Science and Application》 CSCD 2018年第4期531-549,共19页
Computations for air gap response of a semisubmersible platform based on a 3D numerical wave tank approach are presented.The developed method is in time domain and can consider nonlinearities associated with incident ... Computations for air gap response of a semisubmersible platform based on a 3D numerical wave tank approach are presented.The developed method is in time domain and can consider nonlinearities associated with incident wave and hydrostatic forces exactly in determining the body response, but the interaction hydrodynamics of radiation and diffraction are based on simplified linearization assumptions. The incident wave can be defined by any suitable wave theory and here defined by a fully nonlinear numerical wave model. After verifying the present computations results in its degenerated linearized version against the usual linear 3D Green function–based frequency-domain results for air gap predictions, systematic comparative studies are undertaken between linear and the approximate nonlinear solutions. It is found that nonlinear computations can yield considerably conservative predictions as compared to fully linear calculations, amounting to a difference of up to 30%–40% in the minimum air gap in steep ambient incident waves at high and moderate frequencies. 展开更多
关键词 3D NUMERICAL WAVE TANK Air gap responses TIME-DOMAIN APPROACH NUMERICAL WAVE F–Knonlinear
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First-principles study of structure and nonlinear optical properties of CdHg(SCN)_4 crystal
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作者 张鹏 孔垂岗 +5 位作者 郑超 王新强 马跃 冯金波 矫玉秋 卢贵武 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第2期248-252,共5页
The geometric structure,electronic structure,and optical properties of CdHg(SCN)4 crystal are calculated by using the density functional perturbation theory and Green function screening Coulomb interaction approxima... The geometric structure,electronic structure,and optical properties of CdHg(SCN)4 crystal are calculated by using the density functional perturbation theory and Green function screening Coulomb interaction approximation.The band gap of CdHg(SCN)4 crystal is calculated to be 3.198 eV,which is in good agreement with the experimental value 3.265 eV.The calculated second-order nonlinear optical coefficients are d14 = 1.2906 pm/V and d15 = 5.0928 pm/V,which are in agreement with the experimental results(d14=(1.4 ±0.6) pm/V and d15=(6.0 ±0.9) pm/V).Moreover,it is found that the contribution to the valence band mainly comes from Cd-4d,Hg-5d states,and the contributions to the valence band top and the conduction band bottom predominantly come from C-2p,N-2p,and S-3p states.The second-order nonlinear optical effect of CdHg(SCN)_4 crystal results mainly from the internal electronic transition of(SCN)^-. 展开更多
关键词 CdHg(SCN)4 crystal nonlinear optical properties band gap Green function screening Coulombinteraction approximation density functional perturbation theory
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数字经济发展、人力资本水平与城乡收入差距 被引量:11
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作者 徐伟祁 李大胜 闫玉科 《技术经济与管理研究》 北大核心 2023年第8期33-38,共6页
选取2013一2020年省域面板数据,考察数字经济发展、人力资本水平与城乡收入差距之间的相互作用关系。研究发现:数字经济发展对城乡收入差距存在先缩小后扩大的“U”型影响,而农村人力资本水平的提高能够显著强化数字经济发展初期缩小城... 选取2013一2020年省域面板数据,考察数字经济发展、人力资本水平与城乡收入差距之间的相互作用关系。研究发现:数字经济发展对城乡收入差距存在先缩小后扩大的“U”型影响,而农村人力资本水平的提高能够显著强化数字经济发展初期缩小城乡收入差距的积极作用,抑制数字经济发展后期扩大城乡收入差距的消极作用。机制检验表明,非农就业和农业生产率是数字经济影响城乡收入差距的两大路径。进一步分析发现,目前中国东部地区数字经济发展水平正快速逼近“U”型拐点,其他地区离拐点仍有一定距离且逼近速度缓慢。研究结论有利于深刻把握数字经济发展影响城乡收入差距的作用规律。 展开更多
关键词 数字经济 人力资本水平 城乡收入差距 非线性影响
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不同温度下直流电缆气隙缺陷周围空间电荷的分布 被引量:1
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作者 许瑶 方春华 +4 位作者 高广德 李亚莎 侯正宇 崔岩 周国锐 《陕西科技大学学报》 北大核心 2023年第1期151-158,共8页
直流电缆气隙等缺陷的引入会导致空间电荷聚集,且由于导体散发热量绝缘层由内至外形成温度梯度会进一步影响电荷的分布,引起绝缘内部电场畸变.通过COMSOL建立高压电缆本体非线性电导模型,研究温度梯度和电场共同作用下气隙周围空间电荷... 直流电缆气隙等缺陷的引入会导致空间电荷聚集,且由于导体散发热量绝缘层由内至外形成温度梯度会进一步影响电荷的分布,引起绝缘内部电场畸变.通过COMSOL建立高压电缆本体非线性电导模型,研究温度梯度和电场共同作用下气隙周围空间电荷及电场的瞬态分布规律,分析温度梯度、外加电场和气隙的位置与大小对空间电荷分布的影响.结果表明:气隙周围会聚集大量空间电荷,且温度越高,电荷聚集越严重,迁移速率越快;温度梯度为60℃时,气隙低温侧电荷密度为0.78 C/m^(3),场强畸变为1.21倍;气隙周围空间电荷密度随半径的减小而增大,且气隙越靠近高温侧空间电荷密度越大,场强畸变越明显.研究结果为解决直流电缆缺陷造成空间电荷的聚集问题提供理论依据. 展开更多
关键词 高压直流电缆 气隙 电导非线性 温度梯度 空间电荷 电场
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全动舵系统柔性多体动力学建模方法
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作者 杨执钧 张忠 +2 位作者 李芮 高博 郭静 《航天器环境工程》 CSCD 北大核心 2023年第5期447-454,共8页
全动舵系统作为航天飞行器控制飞行姿态、调整飞行方向的部件,其动态特性对飞行器的正常工作起重要作用。为了开展带有电机伺服系统和舵轴间隙的全动舵系统动力学特性分析,提出基于柔性多体动力学方法的全动舵系统建模方法:采用Craig-Ba... 全动舵系统作为航天飞行器控制飞行姿态、调整飞行方向的部件,其动态特性对飞行器的正常工作起重要作用。为了开展带有电机伺服系统和舵轴间隙的全动舵系统动力学特性分析,提出基于柔性多体动力学方法的全动舵系统建模方法:采用Craig-Bampton方法建立典型舵面刚柔耦合降阶模型,采用多体动力学方法建立电动舵机连接机构与全动舵面连接,采用偶极子网格法建立基于模态的广义气动力模型。仿真结果表明,自建的模型预测颤振速度为1270 m/s,与商用软件预测对比的偏差小于2%,验证了该建模方法的正确、可行。研究表明,伺服系统的存在会令典型舵面响应存在较大跳跃现象,而舵轴间隙的存在则极大降低了舵面产生极限环振荡的临界速度。 展开更多
关键词 伺服舵系统 柔性多体动力学 机电耦合 间隙非线性 颤振 极限环振荡
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Synthesis of Poly[(3-octanoylpyrrole-2,5-diyl)-p-nitrobenzylidene] and Its Third-order Nonlinear Optical Property
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作者 ZHANGZhi-gang WUHong-cai YIWen-hui 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2005年第2期220-223,共4页
A novel soluble π-conjugated polymer, poly[(3-octanoylpyrrole-2,5-diyl)-p-nitrobenzylidene] (POPNBE), was synthesized by a five-step reaction. As a result of introducing a long acyl to pyrrole at 3-position, the poly... A novel soluble π-conjugated polymer, poly[(3-octanoylpyrrole-2,5-diyl)-p-nitrobenzylidene] (POPNBE), was synthesized by a five-step reaction. As a result of introducing a long acyl to pyrrole at 3-position, the polymer can be easily solved in polar solvents and be processed into films. The chemical structures of the intermediates and POPNBE were characterized by FTIR, 1H NMR, and UV-Vis-NIR spectrometries. The absorption band in the range of 400-600 nm in the UV-Vis-NIR spectrum is due to the π-π * band gap transition. The optical band gap of POPNBE obtained from the optical absorption is about 1.72 eV. The resonant third-order nonlinear optical property of POPNBE at 532 nm was studied by using the degenerate four-wave mixing(DFWM) technique. The resonant third-order nonlinear optical susceptibility of POPNBE is about 3.42×10 -8 esu. 展开更多
关键词 Poly[(3-octanoylpyrrole-2 5-diyl)-p-nitrobenzylidene] Small optical band gap Degenerate four wave-mixing technique Third-order nonlinear optical property
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基于多元非线性回归模型的220kV电缆油终端缺陷场强预测 被引量:3
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作者 纪晓妍 方春华 游海鑫 《智慧电力》 北大核心 2023年第8期96-103,共8页
电缆油终端在施工时留下的主绝缘划伤缺陷将引起场强畸变,进而导致局部放电,引发绝缘故障。建立220 kV电缆终端主绝缘划伤模型,进行网格划分提高计算精度,利用COMSOL Multiphysics仿真软件研究不同缺陷长度、深度以及位置的电场分布,提... 电缆油终端在施工时留下的主绝缘划伤缺陷将引起场强畸变,进而导致局部放电,引发绝缘故障。建立220 kV电缆终端主绝缘划伤模型,进行网格划分提高计算精度,利用COMSOL Multiphysics仿真软件研究不同缺陷长度、深度以及位置的电场分布,提出一种基于多元非线性回归模型的终端缺陷场强预测方法。结果表明:缺陷处场强最大值随长度增大而增大、随深度增大而减小,缺陷位于应力锥根部时场强最大。距应力锥根部20 mm,缺陷长度和深度各为2 mm和1 mm时,缺陷处场强最大值为14.5 MV/m。经回归分析预测,所提方法误差均在5%以内,为故障分析提供一种新的思路。 展开更多
关键词 电缆油终端 气隙缺陷 电场 多元非线性回归
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不同横缝初始间隙的拱形重力坝-地基体系地震响应分析研究
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作者 林易澍 梁辉 +1 位作者 郭胜山 钟红 《三峡大学学报(自然科学版)》 CAS 2023年第5期66-70,共5页
本文构建了某拱形重力坝三维全坝段-地基体系有限元分析模型,综合考虑了坝体横缝和坝基交界面接触非线性,采用基于拉格朗日乘子法的动接触力模型模拟接触非线性问题,采用黏弹性人工边界考虑无限地基辐射阻尼效应,分别开展横缝初始间隙0... 本文构建了某拱形重力坝三维全坝段-地基体系有限元分析模型,综合考虑了坝体横缝和坝基交界面接触非线性,采用基于拉格朗日乘子法的动接触力模型模拟接触非线性问题,采用黏弹性人工边界考虑无限地基辐射阻尼效应,分别开展横缝初始间隙0、2和20 mm下的重力坝-地基体系非线性有限元动力时程分析,揭示不同横缝初始间隙对大坝动力响应的影响,为工程抗震设计提供科学依据. 展开更多
关键词 拱形重力坝三维全坝段 动接触力模型 接触非线性 横缝初始间隙 动力时程分析
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带间隙伸展机构力学仿真研究 被引量:10
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作者 黄铁球 吴德隆 +1 位作者 阎绍泽 张永 《中国空间科学技术》 EI CSCD 北大核心 1999年第3期16-22,共7页
针对带铰接间隙大型桁架式伸展机构的动力学方程,分析了方程的非线性特性,研究了其数值求解方法。以梁和典型伸展机构平面模型为例进行了仿真分析,得到结构的非线性动响应情况,与实验比较,证实了仿真的有效性。最后给出结论。
关键词 展开机构 间隙 非线性 结构力学 仿真 动态响应
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移动载荷作用下非线性连接浮桥的动力响应 被引量:11
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作者 付世晓 崔维成 +1 位作者 陈徐均 林铸明 《上海交通大学学报》 EI CAS CSCD 北大核心 2006年第6期1004-1009,共6页
以非线性有限元方法为基础,考虑桥节间非线性连接的影响,建立了浮桥三维动力响应分析控制方程,并采用超单元方法对系统的运动方程进行缩减;然后用Newmark直接积分和New-ton-Raphson迭代方法求解系统的非线性运动方程,研究了移动载荷作... 以非线性有限元方法为基础,考虑桥节间非线性连接的影响,建立了浮桥三维动力响应分析控制方程,并采用超单元方法对系统的运动方程进行缩减;然后用Newmark直接积分和New-ton-Raphson迭代方法求解系统的非线性运动方程,研究了移动载荷作用下非线性连接浮桥的三维非线性动力响应特性.研究表明,桥节之间连接的非线性特性和间隙的大小对于浮桥的动力响应影响很大,必须加以考虑. 展开更多
关键词 浮桥 移动载荷 动力响应 间隙 非线性
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带间隙空间结构的动力学特性分析 被引量:9
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作者 文荣 吴德隆 《中国空间科学技术》 EI CSCD 北大核心 1998年第1期7-12,共6页
研究带间隙空间结构的动力学问题。着重讨论间隙引起的结构非线性特性,从理论上探讨了一维间隙系统的定量及定性求解方法,并通过伸展机构的试验研究,验证了间隙对结构动力学特性的影响。
关键词 可延展结构 非线性系统 动力学分析 航天结构
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