Switching and Self-trapping Dynamics of Dark Solitons in a Two-Component Bose-Einstein Condensate

Two coupled dark solitons are considered in a two-component Bose-Einstein condensate, and their dynamics are investigated by the variational approach based the renormalized integrals of motion. The stationary states as physical solutions to the describing equations are obtained, and the dynamic mechanism is demonstrated by performing a coordinate of a classical particle moving in an effective potential field. The switching and selftrapping dynamics of the coupled dark vector solitons are discussed by the evolution of the atom population transferring ratio.     

低功耗互补传输门绝热逻辑和时序电路的设计

研究了采用二相非交叠功率时钟的绝热触发器及时序电路的设计，介绍了采用二相无交叠功率时钟的互补传输门绝热逻辑（CPAL）电路，并分析了其工作原理．该电路利用nMOS管自举原理对负载进行全绝热驱动，从而减小了电路整体功耗，且CPAL能耗几乎与工作频率无关．提出了性能良好的低功耗绝热D、T和JK触发器，并与其他几种绝热触发器进行功耗比较．给出了绝热时序电路的一般设计方法，并作为实例采用应用绝热D触发器设计了十进制计数器．SPICE程序模拟表明：设计的电路具有正确的逻辑功能及低功耗的优点．     

非线性抛物方程的时空有限元方法的 估计

The space time adaptive finite element method,continuous in space but discontinuous in time for nonlinear parabolic problems is discussed.The approach is based on a combination of finite element and finite difference techniques using the properties of Lagrange interpolating polynomials on the Radau points.We ignored the restrictions of the space-time meshes which is needed in other conventional methods.Basic error estimates in L^∞(L^2) norm are obtained.     

基态非简并聚合物中的极化子和双极化子的动力学(Ⅰ)--弱电场下研究

文中模拟了在基态非简并聚合物中的极化子和双极化子在弱电场中的运动,研究了在不同简并参数的系统中极化子和双极化子的动力学稳定性,发现在同一个系统中,双极化子比极化子的运动速度慢,晶格振荡小; 在简并参数大的系统中,极化子和双极化子的运动速度都变慢.极化子和双极化子在弱电场下都存在饱和速度,达到饱和速度后, 电场的能量发生了转换.     

Effects of spacing on dynamics of two coupled Bose-Einstein condensates in two finite traps

Interaction between two coupled Bose-Einstein condensates (BECs) is investigated by the variational approach in two finite traps, and the effects of the spacing between the two traps on dynamics of the two BECs are analyzed. The spacing determines the stable condition of stationary states, affects the existence condition of each BEC, and changes the switching and self-trapping effects on the two BECs. The dynamic mechanism is demonstrated by performing a coordinate of classical particle moving in an effective potential field, and confirmed by the evolution of the atom population transferring ratio.     

粘弹性波动方程的H1-Galerkin时空混合有限元分裂格式

构造一维粘弹性波动方程的H¹-Galerkin时空有限元分裂格式.这种新的分裂格式在时空两个方向同时利用有限元离散,具有H¹-Galerkin混合有限元方法和时空有限元方法的优点,如在不受LBB相容性条件限制的同时能够高精度逼近流体的压力和达西速度,有限元空间可以利用不同次数的多项式空间,能同时得到时间和空间两个变量的形式高阶精度等.通过构造时空投影算子并讨论其相关逼近性质,证明了解的存在唯一性和稳定性,给出混合时空有限元解的误差估计,给出数值算例验证了理论推导结果的合理性和算法的有效性,并和传统H¹-Galerkin方法做比较,得到了更小的误差和超收敛阶.     

坚硬岩层下煤柱岩爆前兆规律的探讨

将坚硬岩层下煤柱岩爆视为具有约束的弹性嵌固梁失稳问题，研究其非稳定机制、前兆与过程阐明了在亚临界失稳阶段煤壁前方顶板下沉速率趋于无穷是岩爆临近的便于监测的前兆     

Sobolev方程的时间间断Galerkin有限元方法

引入Sobolev方程的等价积分方程,构造Sobolev方程的新的时间间断Galerkin有限元格式.该格式不仅保持有限元解在时间剖分点处的间断特性,而且避免了传统时空有限元格式中跳跃项的出现,从而降低了格式理论分析和数值模拟的复杂性.证明了Sobolev方程的时间间断而空间连续的时空有限元解的稳定性、存在唯一性、L2...     

粘弹性波动方程的H~1-Galerkin混合有限元方法误差估计(英文)

H1-Galerkin mixed methods are proposed for viscoelasticity wave equation.Depending on the physical quantities of interest,two methods are discussed.The optimal error estimates and the proof of the existence and uniqueness of semidiscrete solutions are derived for problems in one space dimension.And the methods don＇t require the LBB condition.     

正则长波方程的三次配点法

本文讨论了正则长波方程(RLW方程)的三次配点法,得到半离散格式的最优阶误差估计,同时给出基于向后Euler法的全离散格式,并证明了相应的误差估计.