I-fuzzy拓扑中的杨忠道定理

用L-ukasiewicz逻辑语义的方法在I-fuzzy拓扑中引入了I-fuzzy导集的概念,且研究了它的一些性质,进一步在I-fuzzy拓扑空间框架下证明了关于所提出导集的杨忠道定理。     

粘弹性方程全离散化有限体积元格式及数值模拟

 本文利用有限体积元方法研究二维粘弹性方程, 给出一种时间二阶精度的全离散化有限体积元格式, 并给出这种全离散化有限体积元解的误差估计, 最后用数值例子验证数值结果与理论结果是相吻合的. 通过与有限元方法和有限差分方法相比较, 进一步说明了全离散化有限体积元格式是求解二维粘弹性方程数值解的最有效方法之一.     

关于ω-强凸空间的一点注记

本文研究了关于ω-强凸空间和ω-强光滑空间的问题.利用Banach理论的方法,证明了ω-强凸空间和ω-强光滑空间是一对对偶概念,并讨论了ω-强光滑性与其它光滑性之间的关系,用切片统一刻画了ω-强凸空间与ω-强光滑空间的特征,完善了ω-强凸空间及其对偶空间的研究.     

若干近凸空间和近光滑空间的注记

指出了关于近-强凸(近-非常凸、局部近-一致光滑)的两种不同形式的定义实质上是等价的,从而统一了有关文献中的一些结果.     

非常极凸空间的推广及其对偶概念

本文研究了k非常极凸和k非常极光滑空间的问题.利用Banach空间理论的方法,证明了k非常极凸空间和k非常极光滑空间是一对对偶概念,并且k非常极凸空间(k非常极光滑空间)是严格介于k一致极凸空间和k非常凸空间(k一致极光滑空间和k非常光滑空间)之间的一类新的Banach空间,得到了k非常极凸空间和k非常极光滑空间的若干等价刻画以及k非常极凸(k非常极光滑性)与其它凸性(光滑性)之间的蕴涵关系,推广了非常极凸空间和非常极光滑空间,完善了k非常极凸空间及其对偶空间的研究.     

散射体排列方式对二维磁振子晶体带隙结构的影响

本文采用平面波展开法数值计算了由铁圆柱分别按正方排列、三角排列以及六角排列在氧化铕基底材料中构成的二维磁振子晶体带结构,讨论了散射体的不同排列方式对磁振子晶体带隙结构的影响.计算结果表明,三角排列散射体的磁振子晶体能够获得最大的自旋波带隙结构. 关键词： 磁振子晶体 带隙 排列方式     

Magnetic and transport properties of bilayered manganites La1.2Sr1.8Mn2-xGaxO7（x=0,0.08）

The magnetic and electrical properties of nonmagnetic Ga +3 ion substitution for Mn site are investigated in the bilayer manganite La 1.2 Sr 1.8 Mn 2 O 7.When the Mn is substituted by Ga,the ferromagnetic property obviously weakens,the magnetic transition temperature decreases and a spin-glass behaviour occurs at low temperature.Meanwhile,doping causes the resistivity to dramatically increase,the metal-insulator transition temperature to disappear,and a greater magneto-resistance effect to occur at low temperature.These effects result from the fact that Ga substitution dilutes the magnetic active Mn-O-Mn network and weakens the double exchange interaction,and further suppresses ferromagnetic ordering and metallic conduction.     

Exciton states and interband optical transitions in wurtzite InGaN/GaN quantum dot nanowire heterostructures

Within the framework of the effective-mass approximation, the exciton states and interband optical transitions in In_xGa_1−xN/GaN strained quantum dot (QD) nanowire heterostructures are investigated using a variational method, in which the important built-in electric field (BEF) effects, dielectric-constant mismatch and three-dimensional confinement of the electron and hole in In_xGa_1−xN QDs are considered. We find that the strong BEF gives rise to an obvious reduction of the effective band gap of QDs and leads to a remarkable electron-hole spatial separation. The BEF, QD height and radius, and dielectric mismatch effects have a significant influence on exciton binding energy, electron interband optical transitions, and the exciton oscillator strength.     

LO-phonon effect on the exciton binding energy in polar rectangular quantum wires

Longitudinal optical phonon effect on Wannier excitons in polar rectangular quantum wires is studied by a variational approach. The binding energy is calculated and the numerical results for several II-VI and III-V compound semiconductor rectangular quantum wires are given. The results show that the phonon effect reduces the binding energy and cannot be neglected. The phonon contribution to the binding energy is sensitive to the size of the rectangular quantum wire section, and increases with decreasing section area. The results for the GaAs rectangular quantum wires coincide with the experimental results. The calculated binding energy and the phonon effect in II-VI QWWs are both stronger than those in III-V compound systems, and the results for ZnSe QWW are qualitatively in agreement with the experiments.     

第二种椭圆方程构造变系数非线性发展方程的无穷序列新精确解

本文为了获得非线性发展方程的无穷序列新精确解,进一步研究获得了第二种椭圆方程的几类新型解和Bäcklund变换.在此基础上,借助符号计算系统Mathematica,用带强迫项变系数组合KdV方程、(2+1)维和(3+1)维变系数Zakharov-Kuznetsov 方程为应用实例,构造了无穷序列新精确解.这里包括无穷序列Jacobi 椭圆函数光滑孤立子解、无穷序列Jacobi椭圆函数紧孤立子解、无穷序列三角函数紧孤立子解和无穷序列尖峰孤立子解. 关键词： 第二种椭圆方程 Bä cklund 变换 变系数非线性发展方程 无穷序列新精确解