Test of Determination of (p,γ) Astrophysical S-Factors Using the Asymptotic Normalization Coefficients from Neutron Transfer Reactions

The asymptotic normalization coefficients （ANCs） for the virtual decay ^17 O→^16 O＋n are derived from the angular distributions of the 16 O（d, p）^17O reaction leading to the ground and first excited states of ^17O, respectively, using the distorted wave Born approximation and the adiabatic wave approximation. The ANCs of ^17F are then extracted according to charge symmetry of mirror nuclei and used to calculate the astrophysical S-factors of ^16 O（p, γ）^17 F leading to the first two states of ^17 F. The present results are in good agreement with those from the direct measurement. This provides a test of this indirect method to determine direct astrophysical S-factors of （P, γ） reaction. In addition, the S-factors at zero energy for the direct captures to the ground and first excited states of ^17 F are presented, without the uncertainty associated with the extrapolation from higher energies in direct measurement.     

Asymptotic Quasinormal Modes of the Garfinkle-Horowitz-Strominger Dilaton Black Hole

Using the monodromy technique proposed by Motl and Neitzke (.Adv. Theor. Math. Phys. 7(2003)307), we investigate the analytic forms of the asymptotic quasinormal frequencies for the massless scalar perturbation in the Garfinkle-Horowitz-Strominger dilaton spacetime. We find that the real parts of the quasinormal frequencies are TH ln 3. This agrees with that of the quasinormal modes in the Schwarzschild spacetime. Our result implies that Hod‘s conjecture about In 3 is still valid for the black hole spacetime in the string theory.     

Evolution of local ideal helical perturbations in cylindrical plasma

The evolution of a local helical perturbation and its stability property for arbitrary magnetic shear configurations are investigated for the case of in cylindrical geometry. An analytic stability criterion has been obtained which predicts that a strong magnetic shear will enhance the instability in the positive shear region but enhance the stability in the negative shear region. The perturbations with the poloidal and toroidal perturbation mode numbers m/n=1/1 is most unstable due to the stabilizing terms increasing with m. For m/n=1/1 local perturbations in the conventional positive magnetic shear (PMS) configurations, a larger q_{min} exhibits a weaker shear in the core and is favourable to the stability, while in the reversed magnetic shear (RMS) configurations, a larger q_0 corresponds to a stronger positive shear in the middle region, which enhances the instability. No instabilities are found for m≥2 local perturbations. The stability for RMS configuration is not better than that for PMS configuration.     

Exact Travelling Wave Solutions to a Coupled Nonlinear Evolution Equation

By using an improved hyperbola function method, several types of exact travelling wave solutions to a coupled nonlinear evolution equation are obtained, which include kink-shaped soliton solutions, bell-shaped soliton solutions, envelop solitary wave solutions, and new solitary waves. The method can be applied to other nonlinear evolution equations in mathematical physics.     

变系数非线性发展方程的G＇/G展开解

用近年来提出的（G＇/G）展开法首次尝试了对变系数非线性发展方程的求解,并以两类变系数非线性KdV方程为例,且成功得到了新的精确解.实践证明：（G＇/G）展开法不仅适用于常系数非线性发展方程,而且还很好地适用于变系数非线性方程,具有广泛的应用前景.     

一类非线性波动方程的精确行波解

利用改进的G’/G展开方法,借助于计算机代数系统Mathematica成功获得了一大类非线性波动方程一系列新的含有多个参数的精确行波解.这些解包括孤立波解、双曲函数解、三角函数解.     

光子晶体的能态密度及带隙特性

基于平面波展开法数值模拟了硅、锗、磷化铝和氮化镓三代半导体材料构成三角晶格光子晶体的带隙特性,并且验证了文献[3]中这几种材料构成光子晶体能态密度的分布,两者数据吻合较好,研究结果为光子晶体器件的构造提供理论依据。     

六角格子光子晶体带隙特性

应用平面波展开法研究光子晶体的带隙特性,数值模拟空气圆柱半径与晶格常数的比值变化时,TE模和TM模禁带特性,得出六角晶格光子晶体具有较大的TE模和TM模光子禁带带隙,并且具有较高的带隙宽度重合范围。结果为光子晶体器件的制作提供理论依据。     

(2+1)-维Wick类型随机广义KP方程的类孤子解

利用埃尔米特变换和特殊的截断展开法求出(2+1)-维Wick类型随机广义KP方程的类孤子解. 这种方法的基本思想是通过埃尔米特变换把(2+1)-维Wick类型随机广义KP方程变成的(2+1)-维广义变系数KP方程,利用特殊的截断展开方法求出方程的解,然后通过埃尔米特的逆变换求出方程的随机解.     

在二维原子自洽场计算中的Gaussian函数展开方法

报告了在二维原子结构的自洽场计算中,单电子波函数向笛卡尔Gaussian函数展开的基本方法.推导了由s,p和d电子组成的闭壳层和开壳层电子组态的能量表达式,和二维的Hartree-Fock-Roothaan HFR方程,最后给出了二维原子自洽场计算的主要结果精度的讨论.