Correlation function of an optical bistable system with cross-correlated additive white noise and multiplicative colored noise

Considering an optical bistable system with cross-correlated additive white noise and multiplicative colored noise, we study the effects of correlation between the noises on the correlation function C（s） using the unified colored noise approximation and the Stratonovich deeoupling ansatz formalism. The effects of the self-correlation time τ of the multiplicative colored noise and the correlation intensity λ between the two noises are studied with numerical calculation. It is found that C（s） increases with the increase of the self-correlation timeτ, but decreases with the increase of the correlation intensity λ. At large value of τ, there is almost no change for C（s） when τ changes.     

海水入浸数值模拟的特征差分方法和最佳阶l^2误差估计

滨海含水层中的海水入浸数值模拟和理论分析，是环境科学中十分重要的理论和实际问题，其数学模型是一类三维非线性抛物型偏微分方程组的初、边值问题。一个是关于压力的流动方程，另一个是关于含盐浓度的对流扩散方程．在考虑三维有界区域的一般情况，提出一类特征有限差分格式，利用粗细网块结合，变分形式，先验估计理论和技巧，得到最佳阶ｌ２误差估计结果．     

(∈,∈∨q(λ,μ))-模糊子格

给出(∈,∈∨q(λ,μ))-模糊子格的概念,得到了它的一些等价刻画,另外,还研究(∈,∈∨q(λ,μ))-模糊子格的同态像与同态原像的基本性质。其中值得指出的是,当λ=0,μ=1时可以得到R osen feld定义下的模糊子格的相应结果;当λ=0,μ=0.5时可以得到(∈,∈∨q(λ,μ))-模糊子格的相应结果;当λ=0.5,μ=1时则得到(∨,q-)-模糊子格的相应结果。     

一类带扰动项的拟线性抛物型方程解的存在性

主要利用算子的性质证明了一类带扰动项的拟线性方程的L~2(Ω)初值和狄立克莱边值问题解的存在性和唯一性.     

区域发展战略规划群体决策支持系统(Ⅱ)

本文介绍了一个用于区域发展战略规划设计与管理控制支持的群体决策支持系统中的群体决策支持模型部分,内容包括群体支持模型的功能、结构及其相应算法。     

云居山秋季鸟类群落结构

2012年10月,通过对江西省九江市永修县云居山鸟类群落结构进行了调查,总共观察到41种鸟类,隶属于5目、21科。其中雀形目鸟类在个体数量和种类上都占据了绝对优势地位,白头鹎是其中的绝对优势种。在居留型组成上,留鸟无论在个体数量还是种数上都占最高比例,分别占据全部鸟类的94.4%和88.0%。云居山地区鸟类群落多样性指数为2.93,均匀性指数为0.79。在调查的四种鸟类生境中,针叶林群落鸟类多样性最高,为2.63,而灌丛群落的均匀性指数最高,达到0.87。分析结果表明栖息地生产力的高低在很大程度上决定了不同生境鸟类分布的多样性,而栖息地的相似性则决定了鸟类群落组成的相似程度。     

发酵虫草菌粉对免疫抑制小鼠的免疫调节和抗氧化作用

构建免疫抑制小鼠模型,将小鼠随机分为6组,即正常组、模型组、阳性组及发酵虫草菌粉高、中、低剂量组。小鼠以灌胃的方式给予不同剂量发酵虫草菌粉后,CCK-8法测T淋巴细胞和B淋巴细胞增殖,ELISA法测脾淋巴细胞上清IgM、IL-6、IL-10和TNF-α含量,ELISA法测血清IgM,测定肝脏组织中超氧化物歧化酶(SOD)、丙二醛(MDA)水平。发现与模型组相比,发酵虫草菌粉各剂量组均能提高小鼠脾脏T淋巴细胞和B淋巴细胞增殖。随着菌粉剂量的升高,IgM、IL-6、IL-10和TNF-α的含量均升高,SOD活性增强,MDA含量降低。结果表明,发酵虫草菌粉能有效拮抗环磷酰胺的免疫抑制作用,并能提高免疫抑制小鼠的抗氧化能力。 更多还原     

Compound line-of-sight nonlinear path following control of underactuated marine vehicles exposed to wind,waves, and ocean currents

This paper investigates the problem of nonlinear path following control of underactuated marine vehicles in the horizontal plane. Firstly, appropriate kinematic and dynamic models are established, where the kinematic model is developed in terms of the relative velocity with respect to the ocean current disturbances, and the dynamic model is developed to include the effects of wind and wave disturbances. Based on the time delay control method and the reduced-order linear extended state observer (LESOs) technique, an improved compound line-of-sight (CLOS) guidance law is first proposed which can estimate the unknown sideslip angle and can compensate for the effects of time-varying ocean currents. Secondly, the control law is decomposed into the kinematic and dynamic controllers by the back-stepping technique. The high-order tracking differentiator is applied to construct derivatives of desired yaw angle, which are calculated by the CLOS guidance law. This approach resolves the problem of computational complexity inherent in the traditional back-stepping method and simplifies the overall controller. The lumped disturbances caused by waves and wind are estimated and compensated by the reduced-order LESOs. Finally, stability analysis of the closed-loop system is performed. The simulation results and comparative analysis validate the effectiveness and robustness of the proposed control approach.     

On Quadratic Forms Between Spheres

For a quadratic form f: S^m Sⁿ, we first estimate the dimensions of its preimages and determine the cases when the upper bound is achieved. Combining results of Wood and Yiu, we then derive a complete classification of f when m 2n-2. By using orthogonal multiplication, we also introduce a new construction of quadratic forms between spheres, generalizing the classical Hopf construction.     

广义Drinfeld-Sokolov方程的行波解的分支

用Ansatz方法和动力系统理论研究了广义Drinfeld-Sokolov方程的行波解．在给定的两组参数条件下,得到了广义Drinfeld-Sokolov方程更多的孤立波解,扭子和反扭子波解及周期波解,并给出这些行波解精确的参数表示．