This work focuses on how to maintain a high-energy orbit motion of a bistable oscillator when subjected to a low level excitation. An elastic magnifier （EM） positioned between the base and the bistable oscillator is...This work focuses on how to maintain a high-energy orbit motion of a bistable oscillator when subjected to a low level excitation. An elastic magnifier （EM） positioned between the base and the bistable oscillator is used to magnify the base vibration displacement to significantly enhance the output characteristics of the bistable oscillator. The dimensionless electromechanical equations of the bistable oscillator with an EM are derived, and the effects of the mass and stiffness ratios between the EM and the bistable oscillator on the output displacement are studied. It is shown that the jump phenomenon occurs at a lower excitation level with increasing the mass and stiffness ratios. With the comparison of the displacement trajectories and the phase portraits obtained from experiments, it is vMidated that the bistable oscillator with an EM can effectively oscillate in a high-energy orbit and can generate a superior output vibration at a low excitation level as compared with the bistable oscillator without an EM.展开更多
The important role of high-energy intramolecular vibrational modes for excitation energy transfer in the detuned photosynthetic systems is studied. Based on a basic dimer model which consists of two two-level systems ...The important role of high-energy intramolecular vibrational modes for excitation energy transfer in the detuned photosynthetic systems is studied. Based on a basic dimer model which consists of two two-level systems （pigments） coupled to high-energy vibrational modes, we find that the high-energy intramolecular vibrational modes can enhance the energy transfer with new coherent transfer channels being opened when the phonon energy matches the detuning between the two pigments. As a result, the energy can be effectively transferred into the acceptor. The effective Hamiltonian is obtained to reveal the strong coherent energy exchange among the donor, the acceptor, and the high-energy intramolecular. A semi-classical explanation of the phonon-assisted mechanism is also shown.展开更多
Configuration-constrained potential-energy-surface calculations have been performed to investigate the K isomerism in the proton-rich A～ 80 mass region. An abundance of high-K states are predicted. These high-K state...Configuration-constrained potential-energy-surface calculations have been performed to investigate the K isomerism in the proton-rich A～ 80 mass region. An abundance of high-K states are predicted. These high-K states arise from two and four-quasi-particle excitations, with K^π= 8^＋ and K^π= 16^＋, respectively. Their excitation energies are comparatively low, making them good candidates for long-lived isomers. Since most nuclei under study are prolate spheroids in their ground states, the oblate shapes of the predicted high-K states may indicate a combination of K isomerism and shape isomerism.展开更多
提出了统计声学能量流（statistical acoustic energy flow,SAEF）方法,将不同物理场的激励耦合后加载到高铁SAEF模型上,计算车外激励与车内声场及车内声腔之间的声能流动,可分析车内全频噪声.首先,采用刚性多体动力学、快速多极边界元...提出了统计声学能量流（statistical acoustic energy flow,SAEF）方法,将不同物理场的激励耦合后加载到高铁SAEF模型上,计算车外激励与车内声场及车内声腔之间的声能流动,可分析车内全频噪声.首先,采用刚性多体动力学、快速多极边界元和大涡模拟提取了350,km/h下的轮轨力/二系悬挂力、轮轨噪声和空气动力噪声,并且这些激励通过了参考文献试验的验证.其次,搭建了车厢有限元模型,基于多点激励-多点响应技术验证了车厢仿真模态,证明了整体的车厢及区域的铝型材-内饰组合板的精度,间接保证了基于模态特性的组合板隔声量的准确度.最后,搭建了SAEF模型,加载耦合激励并定义组合板隔声性能后,计算了350,km/h下、0~4,000,Hz内的车内噪声.对比车内中心声腔的仿真与试验声压级,结果显示两者的变化趋势基本一致,声压级总值相差2.6,d B（A）,符合工程要求,验证了SAEF方法应用于高铁车内全频噪声研究的可行性.展开更多
High spin states in the odd-odd nucleus 124Cs have been investigated through the fusion-evaporation reaction 116Sn（11B, 3n）l24 Cs with a beam energy of 45 MeV. A new rotational band is established and assigned as th...High spin states in the odd-odd nucleus 124Cs have been investigated through the fusion-evaporation reaction 116Sn（11B, 3n）l24 Cs with a beam energy of 45 MeV. A new rotational band is established and assigned as the high-k configuration of πg9/2140419/2＋ ⊙vh 11/2[523]7/2-. Some structures linking to this band have also been observed. According to the results of the excitation energy systematics, the lowest level of this band is assigned as 9-, and the 8- isomer bandhead has not been observed. Another isomer with a half life of 6.3 s has also been observed with its new decay paths established, Its excitation energy is raised by 79 keV, but its Iπ is not changed.展开更多
The phonon-assisted process of energy transfer aiming at exploring the newly emerging frontier between biology and physics is an issue of central interest.This article shows the important role of the intramolecular vi...The phonon-assisted process of energy transfer aiming at exploring the newly emerging frontier between biology and physics is an issue of central interest.This article shows the important role of the intramolecular vibrational modes for excitation energy transfer in the photosynthetic systems.Based on a dimer system consisting of a donor and an acceptor modeled by two two-level systems,in which one of them is coupled to a high-energy vibrational mode,we derive an effective Hamiltonian describing the vibration-assisted coherent energy transfer process in the polaron frame.The effective Hamiltonian reveals in the case that the vibrational mode dynamically matches the energy detuning between the donor and the acceptor,the original detuned energy transfer becomes resonant energy transfer.In addition,the population dynamics and coherence dynamics of the dimer system with and without vibration-assistance are investigated numerically.It is found that,the energy transfer efficiency and the transfer time depend heavily on the interaction strength of the donor and the high-energy vibrational mode,as well as the vibrational frequency.The numerical results also indicate that the initial state and dissipation rate of the vibrational mode have little influence on the dynamics of the dimer system.Results obtained in this article are not only helpful to understand the natural photosynthesis,but also offer an optimal design principle for artificial photosynthesis.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 51277165the Natural Science Foundation of Zhejiang Province under Grant No LY15F10001
文摘This work focuses on how to maintain a high-energy orbit motion of a bistable oscillator when subjected to a low level excitation. An elastic magnifier （EM） positioned between the base and the bistable oscillator is used to magnify the base vibration displacement to significantly enhance the output characteristics of the bistable oscillator. The dimensionless electromechanical equations of the bistable oscillator with an EM are derived, and the effects of the mass and stiffness ratios between the EM and the bistable oscillator on the output displacement are studied. It is shown that the jump phenomenon occurs at a lower excitation level with increasing the mass and stiffness ratios. With the comparison of the displacement trajectories and the phase portraits obtained from experiments, it is vMidated that the bistable oscillator with an EM can effectively oscillate in a high-energy orbit and can generate a superior output vibration at a low excitation level as compared with the bistable oscillator without an EM.
基金Project supported by the National Natural Science Foundation of China(Grant No.11174233)
文摘The important role of high-energy intramolecular vibrational modes for excitation energy transfer in the detuned photosynthetic systems is studied. Based on a basic dimer model which consists of two two-level systems （pigments） coupled to high-energy vibrational modes, we find that the high-energy intramolecular vibrational modes can enhance the energy transfer with new coherent transfer channels being opened when the phonon energy matches the detuning between the two pigments. As a result, the energy can be effectively transferred into the acceptor. The effective Hamiltonian is obtained to reveal the strong coherent energy exchange among the donor, the acceptor, and the high-energy intramolecular. A semi-classical explanation of the phonon-assisted mechanism is also shown.
基金Supported by National Key Basic Research Program of China(2013CB834402)National Natural Science Foundation of China(11235001,11320101004 and 11575007)
文摘Configuration-constrained potential-energy-surface calculations have been performed to investigate the K isomerism in the proton-rich A～ 80 mass region. An abundance of high-K states are predicted. These high-K states arise from two and four-quasi-particle excitations, with K^π= 8^＋ and K^π= 16^＋, respectively. Their excitation energies are comparatively low, making them good candidates for long-lived isomers. Since most nuclei under study are prolate spheroids in their ground states, the oblate shapes of the predicted high-K states may indicate a combination of K isomerism and shape isomerism.
文摘提出了统计声学能量流（statistical acoustic energy flow,SAEF）方法,将不同物理场的激励耦合后加载到高铁SAEF模型上,计算车外激励与车内声场及车内声腔之间的声能流动,可分析车内全频噪声.首先,采用刚性多体动力学、快速多极边界元和大涡模拟提取了350,km/h下的轮轨力/二系悬挂力、轮轨噪声和空气动力噪声,并且这些激励通过了参考文献试验的验证.其次,搭建了车厢有限元模型,基于多点激励-多点响应技术验证了车厢仿真模态,证明了整体的车厢及区域的铝型材-内饰组合板的精度,间接保证了基于模态特性的组合板隔声量的准确度.最后,搭建了SAEF模型,加载耦合激励并定义组合板隔声性能后,计算了350,km/h下、0~4,000,Hz内的车内噪声.对比车内中心声腔的仿真与试验声压级,结果显示两者的变化趋势基本一致,声压级总值相差2.6,d B（A）,符合工程要求,验证了SAEF方法应用于高铁车内全频噪声研究的可行性.
基金supported by National Natural Science Foundation of China(Nos.10105003,11075064,11075214 and 10927507)the Specialized Research Fund for the Doctoral Programme of Higher Education of China(No.20050183008)the National Basic Research Programme of China(No.2007CB815005)
文摘High spin states in the odd-odd nucleus 124Cs have been investigated through the fusion-evaporation reaction 116Sn（11B, 3n）l24 Cs with a beam energy of 45 MeV. A new rotational band is established and assigned as the high-k configuration of πg9/2140419/2＋ ⊙vh 11/2[523]7/2-. Some structures linking to this band have also been observed. According to the results of the excitation energy systematics, the lowest level of this band is assigned as 9-, and the 8- isomer bandhead has not been observed. Another isomer with a half life of 6.3 s has also been observed with its new decay paths established, Its excitation energy is raised by 79 keV, but its Iπ is not changed.
基金Project supported by the National Natural Science Foundation of China(Grant No.11174233)
文摘The phonon-assisted process of energy transfer aiming at exploring the newly emerging frontier between biology and physics is an issue of central interest.This article shows the important role of the intramolecular vibrational modes for excitation energy transfer in the photosynthetic systems.Based on a dimer system consisting of a donor and an acceptor modeled by two two-level systems,in which one of them is coupled to a high-energy vibrational mode,we derive an effective Hamiltonian describing the vibration-assisted coherent energy transfer process in the polaron frame.The effective Hamiltonian reveals in the case that the vibrational mode dynamically matches the energy detuning between the donor and the acceptor,the original detuned energy transfer becomes resonant energy transfer.In addition,the population dynamics and coherence dynamics of the dimer system with and without vibration-assistance are investigated numerically.It is found that,the energy transfer efficiency and the transfer time depend heavily on the interaction strength of the donor and the high-energy vibrational mode,as well as the vibrational frequency.The numerical results also indicate that the initial state and dissipation rate of the vibrational mode have little influence on the dynamics of the dimer system.Results obtained in this article are not only helpful to understand the natural photosynthesis,but also offer an optimal design principle for artificial photosynthesis.
