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粘弹性材料的微振子模型研究 被引量:9
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作者 石银明 华宏星 傅志方 《振动工程学报》 EI CSCD 北大核心 2001年第1期100-104,共5页
针对利用粘弹性材料进行结构主被动控制的需要 ,建立了一套确定微振子模型各参数的方法 ,并且与标准流变模型、分数导数模型以及试验结果进行比较 ,算例表明确定微振子模型各参数的方法有效 ,同时也表明微振子模型不但能准确描述粘弹性... 针对利用粘弹性材料进行结构主被动控制的需要 ,建立了一套确定微振子模型各参数的方法 ,并且与标准流变模型、分数导数模型以及试验结果进行比较 ,算例表明确定微振子模型各参数的方法有效 ,同时也表明微振子模型不但能准确描述粘弹性材料的本构关系 ,而且能与有限元方法相融合 ,建立二阶线性系统 ,能很方便地利用线性系统控制理论进行控制设计。 展开更多
关键词 粘弹性材料 复合结构 微振子模型 振动控制 减振材料 线性系统控制理论
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线性粘弹结构有限元模型的鲁棒降阶方法 被引量:4
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作者 石银明 华宏星 +1 位作者 李中付 傅志方 《振动与冲击》 EI CSCD 北大核心 2001年第1期16-19,共4页
为了对粘弹性材料复合结构进行静动力分析及主被动控制 ,采用微振子模型描述线性粘弹材料的本构关系 ,先用有限元方法对结构进行离散 ,然后引入耗散自由度 ,将非线性的有限元方程转化为普通的二阶系统 ,最后从系统的可控性、可观性出发... 为了对粘弹性材料复合结构进行静动力分析及主被动控制 ,采用微振子模型描述线性粘弹材料的本构关系 ,先用有限元方法对结构进行离散 ,然后引入耗散自由度 ,将非线性的有限元方程转化为普通的二阶系统 ,最后从系统的可控性、可观性出发提出了一种模型的鲁棒降阶方法。算例表明微振子模型与有限元相结合 ,能很方便地求出固有频率、阻尼等模态参数及响应。鲁棒降阶算法稳定 ,能为下一步进行主动控制做好准备。 展开更多
关键词 粘弹性材料 微振子模型 有限元方法 鲁棒降价 振动控制 线性粘弹结构
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主动约束层阻尼悬臂梁的有限元分析及实验研究 被引量:3
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作者 华宏星 石银明 +2 位作者 刘天雄 傅志方 史习智 《振动工程学报》 EI CSCD 北大核心 2002年第4期383-388,共6页
针对具体实物模型 ,采用微振子模型描述粘弹性材料的剪切模量随频率变化的特性 ,采用有限元方法进行分析 ,提出了一种全新的降阶方法 ,使得最后的降阶模型不仅维数远小于初始有限元模型 ,而且可观、可控 ,能直接用于控制器设计。采用模... 针对具体实物模型 ,采用微振子模型描述粘弹性材料的剪切模量随频率变化的特性 ,采用有限元方法进行分析 ,提出了一种全新的降阶方法 ,使得最后的降阶模型不仅维数远小于初始有限元模型 ,而且可观、可控 ,能直接用于控制器设计。采用模态实验验证有限元模型 ,在此基础上 ,设计出合适的控制器 ,进行实时控制实验研究 ,结果表明 。 展开更多
关键词 悬臂梁 实验研究 振动控制 主动约束层阻尼 有限元分析 微振子模型
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Cavity-Enhanced Third Harmonic Generation
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作者 YANGXiao-Xue WUYing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2期318-320,共3页
We derive the analytical expression of microcavity-enhanced factor for third harmonic generation in terms of detunings, linewidths, and the Purcell factors of the relevant microcavity modes. It is suitable for microca... We derive the analytical expression of microcavity-enhanced factor for third harmonic generation in terms of detunings, linewidths, and the Purcell factors of the relevant microcavity modes. It is suitable for microcavities with any dimensions and arbitrary geometric shapes. 展开更多
关键词 MICROCAVITIES third harmonic generation quantum optics multi-wave mixing
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Description of N=7~9 Isotones with a Modified Single-Particle Potential
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作者 GUO Yan-Qing REN Zhong-Zhou CHEN Yu-Qing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第12期1396-1400,共5页
We study the level structures of N = 7 - 9 isotones and their mirror nuclei in the framework of the single-particle potential model. Considering the limitation of the conventional potential-model calculation, the isos... We study the level structures of N = 7 - 9 isotones and their mirror nuclei in the framework of the single-particle potential model. Considering the limitation of the conventional potential-model calculation, the isospindependent 12 coupling is newly introduced in the average potential. The modified model gives a unified description for the structures of all studied nuclei. Galculations self-consistently produce the s-d level inversion in N = 9 isotones and their mirror nuclei. Meanwhile, the s-p level inversion in the mirror nuclei ^11Be and ^11N is reproduced. The study confirms the neutron halo structures in ^11Be(2s1/2), ^11Be(1p1/2), ^12B(2s1/2), ^14B(2s1/2), ^13C(2sl/2), ^15C(2s1/2) and the proton halo structure in ^17F(2s1/2). The agreement between theory and experiment indicates that the inclusion of the i2 coupling is a feasible way to explain the abnormal structures of exotic light nuclei. 展开更多
关键词 modified single-particle potential level inversion l^2 coupling
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Weighing neutrinos in dynamical dark energy models 被引量:1
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作者 Xin Zhang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2017年第6期86-88,共3页
The discovery of neutrino oscillation indicates that neutrinos have masses and each flavor state is actually a superposition of three mass states with masses m1,m2,and m3.However,the neutrino oscillation experiments a... The discovery of neutrino oscillation indicates that neutrinos have masses and each flavor state is actually a superposition of three mass states with masses m1,m2,and m3.However,the neutrino oscillation experiments are not able to measure the absolute masses of neutrinos,but can only measure the squared mass differences between the neutrino mass eigenstates—The solar and reactor experiments gave 展开更多
关键词 dynamical superposition accelerator flavor inverted absolute hierarchy actually oscillation constraint
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Matter Effects on Neutrino Oscillations in Different Supernova Models
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作者 徐晶 胡立军 +2 位作者 李瑞成 郭新恒 杨炳麟 《Communications in Theoretical Physics》 SCIE CAS CSCD 2016年第4期506-516,共11页
In recent years,with the development of simulations about supernova explosion,we have a better understanding about the density profiles and the shock waves in supernovae than before.There might be a reverse shock wave... In recent years,with the development of simulations about supernova explosion,we have a better understanding about the density profiles and the shock waves in supernovae than before.There might be a reverse shock wave,another sudden change of density except the forward shock wave,or even no shock wave,emerging in the supernova.Instead of using the expression of the crossing probability at the high resonance,PH,we have studied the matter effects on neutrino oscillations in different supernova models.In detail,we have calculated the survival probability of νe(P_s)and the conversion probability of ν_x(P_c) in the Schrodinger equation within a simplified two-flavor framework for a certain case,in which the neutrino transfers through the supernova matter from an initial flavor eigenstate located at the core of the supernova.Our calculations was based on the data of density in three different supernova models obtained from simulations.In our work,we do not steepen the density gradient around the border of the shock wave,which differs to what was done in most of the other simulations.It is found that the mass and the density distribution of the supernova do make a difference on the behavior of P_s and P_c.With the results of P_s and P_c,we can estimate the number of νe(and ν_x) remained in the beam after they go through the matter in the supernova. 展开更多
关键词 neutrino oscillations matter effects shock wave effects supernova models
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