多振子声子晶体的低频特性研究

本文设计了一种由硅橡胶包覆层包裹4个钨振子的新型声子晶体结构,通过有限元法计算该结构的色散曲线、振动模态和传输损失谱。结果表明,该结构的带隙范围为18.85~225.28 Hz,与传输损失谱频率衰减范围相吻合,能够有效抑制20~200 Hz的弹性波在声子晶体中传播。通过分析色散曲线上点的振动模态,说明带隙产生的原因。本文讨论了声子晶体板的缺口角度和振子之间的纵向和横向间距对带隙的影响,结果表明:当缺口角度减小时,带隙下边界几乎保持不变,带隙上边界升高从而增加了带隙的宽度;振子之间横向或纵向间距增大时,带隙下边界和上边界均上升,带隙变宽,进而优化了声子晶体模型的带隙。同时声子晶体板的缺口设计能够节省材料,从而减轻结构的质量。     

De-excitation Energy of Superdeformed Secondary Minima of Odd-Odd Au Isotopes and Its Sensitivity to the Density Dependence of Symmetry Energy

The de-excitation energy of superdeformed secondary minima of odd-odd Au isotopes is investigated using the relativistic mean field model with the inclusion of the isoscalar-isovector coupling. It is shown that the de-excitation energies of superdeformed secondary minima relative to the ground states can serve as a significant probe to the density dependence of the symmetry energy.     

优化MGM(1,n)模型及其应用研究

从最小二乘估计的适用条件出发,在建立MGM(1,n)模型前,先采用BoxCox变换对原始数据进行变换,以解决或缓解误差项的正态性偏离问题.首先,以模型拟合平均误差最小化为目标,建立非线性优化模型,在参数的置信区间内,应用PSO(Particle Swarm Optimization)算法求最优解.然后,应用求解得到的参数,建立优化MGM(1,n)模型.在实例分析中,将优化MGM(1,n)模型应用于深基坑围护结构变形预测,实验结果表明通过对原始数据做合适的Box-Cox变换,能够有效提高模型的拟合及预测精度,拓广多变量灰色预测模型的适用范围.     

Janus二维双层MoSSe/WSSe异质结光电性质的第一性原理研究

通过第一性原理计算研究了四种二维双层MoSSe/WSSe范德瓦耳斯异质结的光电性质。声子谱表明四种结构具有可靠的热力学稳定性。根据堆垛方式的不同，双层MoSSe/WSSe异质结可以是间接或直接半导体。而且，两种Janus型MoSSe/WSSe异质结具有1.22和1.88 eV的适中带隙、显著的可见光吸收系数、跨越了水氧化还原电位的带边位置。因此，Janus型的MoSSe/WSSe异质结构在光催化水分解领域具有一定的应用前景。     

做有思想的教师，培养有理想的学生——上海市延安中学数学组简介

上海市延安中学数学组是上海市“工人先锋号”，曾被评为全国先进班组，荣获全国“五一劳动”奖章：自1987年以来，曾连续8届荣获“上海市劳模集体”称号：从2002年至今，已连续3届获上海市共青团号称号。数学组有一支思想过硬、技术过硬的教师队伍。组内有4名特级教师、1名区专业技术拔尖人才、7名区学科带头人、5名中国数学奥林匹克高级教练员。数学组现任组长吕志勇连续两届成为长宁区专业技术拔尖人才，是上海市第一届名师培训基地学员。     

Isospin violating mechanisms in quarkonium hadronic decays

We analyze the φ meson production in e^＋e^- →ωπ^0 as a probe for studying the isospin violation mechanisms. By clarifying the dynamic sources causing the isospin violation, we succeed in quantifying those mechanisms with the help of the recent KLOE data. Hence, the φ→ωπ^0 branching ratio is extracted. We find that apart from the electromagnetic （EM） transitions, the strong transition via intermediate kaon loops plays an important role in understanding the cross section and its lineshape.     

Rayleigh Scattering for An Electromagnetic Anisotropic Medium Sphere

Based on the scales theory of electromagnetic waves, the analytical expression of electrical fields inside an anisotropic medium sphere is studied. Differential scattering cross section and radar cross section （RCS） for an anisotropic spherical target are presented. The correctness of the obtained results is tested. The simulation results show that the scattering of an anisotropic sphere has the property of a dipole radiation under the condition of Rayleigh scattering. The larger the dielectric constant is, the stronger the dipole scattering is. Anisotropy in magnetism only has an effect on differential RCS. These results provide a theoretical base for the identification of anisotropic targets.     

第十五届全国原子与分子物理学术会议投稿论文:粒子在 Hénon-Heiles势中的逃逸动力学模拟

利用庞加莱截面和相空间轨迹方法对粒子在Hénon-Heiles势中的逃逸动力学进行了模拟。粒子的动力学性质敏感地依赖于粒子的能量。数值计算表明当能量很小时，粒子的运动是规则的；随着能量的增加，粒子的运动开始出现混沌。当能量增加到鞍点能 时,几乎所有的相空间轨迹都是混沌的。当粒子的能量 , 粒子可以越过势阱发生逃逸。对于给定的大于 的能量, 我们画出了粒子的逃逸－时间曲线和逃逸轨迹。我们的研究对于研究混沌传输和逃逸动力学具有一定的参考价值。     

Microwave Magnetic Properties and Natural Resonance of e-Co Nanoparticles

Owing to the novel crystal structure, ε-Co nanoparticles with an average diameter of 12 nm are synthesized and the microwave magnetic properties of the epoxy resin composite with 50voi% ε-Co particles are measured in the frequency range 0.1-7 GHz. The experimental resonance frequency （4.7 GHz） matches well with the values obtained by the theoretical calculation with the Kittel equation and fitting the experimental permeability dispersion curve via the Landan-Lifshitz equation. Hence the resonance peak is attributed to natural resonance mode. This work is believed to be beneficial for further understanding microwave applications of the novel ε-Co nanoparticles.