NEW METHOD FOR LOW ORDER SPECTRAL MODEL AND ITS APPLICATION

In order to overcome the deficiency in classical method of low order spectral model, a new method for low order spectral model was advanced. Through calculating the multiple correlation coefficients between combinations of different functions and the recorded data under the least square criterion, the truncated functions which can mostly reflect the studied physical phenomenon were objectively distilled from these data. The new method overcomes the deficiency of artificially selecting the truncated functions in the classical low order spectral model. The new method being applied to study the inter-annual variation of summer atmospheric circulation over Northern Hemisphere, the truncated functions were obtained with the atmospheric circulation data of June 1994 and June 1998. The mechanisms for the two-summer atmospheric circulation variations over Northern Hemisphere were obtained with two-layer quasi-geostrophic baroclinic equation.     

部分均匀荷载作用下圆板塑性极限统一解

本文采用俞茂宏双剪统一屈服准则求解部分均匀荷载下简支圆板的塑性极限，已有的最大主应力准则、Ｔｒｅｓｃａ准则，Ｍｉｓｅｓ准则的解答均是该解答的特例或线性逼近。该解答可以适合于多种工程材料，具有普遍性和适用性，从得出的解析解和图示中可得出一些新的有益的认识     

裂纹尖端大范围屈服时的能量耗散率研究

裂纹尖端大范围屈服时的能量耗散率研究李肇飞（青岛建筑工程学院基础部，青岛２６６０３３）随着弹塑性断裂理论研究的不断深入，近年来不少文献采用了能量耗散率的概念．本文对此从理论上进行了论证并结合文献［１，２］中给出的数据，对其物理意义进行了讨论．１理论分...     

强不可约算子的K0群及其近似相似不变量

令 $\mathcal H$ 表示复可分的Hilbert空间, ${\mathcal L}({\mathcal H})$ 表示 $\mathcal H$上全体有界线性算子的集合. 算子 $T \in{\mathcal L}{(\mathcal H)}$称为是强不可约的, 如果不存在非平凡的幂等元与 T 可交换. 对强不可约算子的近似不变量给出比以往文献更精细的刻画. 主要结果如下: 对任意具有连通谱的有界线性算子 T 及 ε>0, 存在强不可约算子A, 使得 $\|A-T\|<\varepsilon$, $V({\mathcal A}^{\prime}(A))\cong{\mathbb{N}}$, $K_{0}({\mathcal A}^{\prime}(A))\cong{\mathbb{Z}}$, 且 ${{\mathcal A}^{\prime}(A)}/{\rm rad}{{\mathcal A}^{\prime}(A)}$ 可交换, 这里${\mathcal A}^{\prime}(A)$ 表示A 的换位代数, 且 ${\rm rad}{\mathcal A}^{\prime}(A)$ 表示${\mathcal A}^{\prime}(A)$的Jacobson根.     

高阶非线性Schrdinger方程的自相似解

研究非线性项的形式为|u|~pu,p>0的2m阶非线性Schrdinger方程的自相似解.利用scaling和压缩映象原理证明了当初值满足一定条件时Cauchy问题解的整体存在性,据此给出了当初值的形式为U(x/(|x|))|x|~(-(2m)/p)时,自相似解的存在性.     

带有区间型三角模糊数的多目标规划模型算法

给出了模糊多目标线性规划模型的一种有效算法,其中目标函数和约束条件中的系数都是区间型三角模糊数.首先,通过引入区间型三角模糊数的截集,将模糊多目标函数转化成单目标函数.其次,引入用于比较两个三角模糊数的强占优可能性准则,将模型中的模糊约束条件转化为经典不等式组.然后,利用Matlab软件编程求解转化的经典单目标线性规划...     

基于特征结构相似度的遥感影像融合质量评价指标

在分析现有影像融合评价指标的基础上,根据人眼视觉特性,提出一种基于特征结构相似度的遥感影像融合评价指标.首先从原始影像和融合影像中提取空间特征和光谱特征,然后综合计算空间特征和光谱特征的结构相似度作为评价指标,达到评价影像质量的目的.通过对多种传感器获取的遥感影像进行融合实验,结果表明该客观评价方法与主观评价结果一致,...     

Study of the excitation properties of the Si3O2 cluster under an external electric field

The structure of the Si₃O_x (x=2, 3) cluster is investigated; we find that the geometry of Si₃O₂ is similar to that of Si₃O₃ except for the oxygen-deficient defect structure (Si-Si band) which exists only in the Si₃O₂ cluster. It is known that oxygen-deficient defects are used to explain visible luminescence (especially blue, purple and ultraviolet light) from silicon-based materials, which are directly bound up with the excited states of the molecules. Therefore the excitation properties of the two clusters are also studied. Our results show that the absorption spectrum of Si₃O₂ is concentrated in the visible light region. In contrast, the absorption spectrum of Si₃O₃ is mainly located in the ultraviolet light region. The calculations are perfectly consistent with experimental data and also support the theory of oxygen-deficient defects.     

一种基于多特征融合的新型光谱相似性测度

光谱相似性测度是高光谱遥感影像定量化分析和精细地物直接识别的基础,光谱特征的选择和刻画方式是光谱相似性测度的关键.研究表明,利用光谱的单一特征无法全面反应地物光谱间的相似性,光谱识别时需要综合考虑光谱的多种特征.本文在几何距离、相关系数和相对熵的基础上提出了一种结合多种光谱特征的新型光谱相似性测度,即光谱泛相似测度(s...