Van der Waals superlatticesOA

<正>Semiconductor technology has enabled many essential devices,including transistors for computing and communication,diodes for solid-state lighting and photovoltaics.Behind all these devices,the material foundation is a series of highly elaborated heterostructures and superlattices[1].To this end,integrating different materials into heterostructures or superlattices with well-defined spatial modulation of chemical compositions and electronic structures is central for generating designed e...     

Improved van der Pol Oscillators

This paper brings together and discusses some useful oscillator models. A unified approach is used to present different models in an evolutionary succession of ascending complexity. The presentation applies a rather informal physical viewpoint without stressing mathematical rigorosity. Applications of the models are also mentioned.     

强迫Duffing—Van der Pol振子的混沌行为

用Melnikov-Holmes方法对如下强迫Duffing-Van der Pol振子进行了分析:给出其同宿轨道的Melnikov函数及系统产生混沌的阈值.通过数值计算,运用运动轨线的直接观察,相图分析和FFT功率谱分析方法,考察系统的周期和混沌行为.并着重研究了反馈周期驱动对系统混沌行为的影响.在小参数范围内,数值结果与理论结果符合较好.本文的研究结果将为解决非线性系统的噪声干扰问题以及获得在统计分析和Monte Carlo方法中极为有用的具有给定分布的随机信号等提供途径.     

Biological applications of the “Filtered” Van der Pol oscillator

The present article deals with the development of an oscillatory model, which generates waveforms corresponding to ECG patterns. The present oscillatory system relies on coupling of oscillators derived from the famous VDP oscillator. We demonstrate that inducing a relaxation type of dynamics in the models contributes to their successful generation of ECG like signals. Furthermore, an interesting affinity is found, which associates the present models with a version of the well-known practical Wien Bridge oscillator. The presently discussed system relies on coupled elementary oscillator units. The present coupling is due to merely two units. The model, however, is likely to become even more realistic by coupling in the same manner an assembly of relatively many oscillators.     

新形势下中学生心理健康教育发展趋势

心理健康教育应伴随在学生学习的每一个阶段,而学生的心理问题在中学时期表现得尤为明显,所以应当更加重视对学生健康心理的培养。然而,目前心理健康教育的课程与真正达到促进学生心理的健康发展,还存在一定的距离,本文简要介绍了心理健康教育的概念,通过综合心理健康教育发展趋势的相关研究总结了心理健康教育的不足,对其今后的发展趋势提出了一些思考。     

新形势下民办高校文化建设探析

文化建设是民办高校一项重要而紧迫的任务。新形势下,面对“90后”群体特征,民办高校应紧紧围绕精神文明建设的核心,结合实际进一步提升物质文化、制度文化、行为文化建设,提炼和塑造有特色的民办高校文化。     

The 2001 Benjamin Franklin Medal in Earth Science presented to Rob Van der Voo

The Franklin Institute, Philadelphia, Pennsylvania, awarded the 2001 Benjamin Franklin Medal in Earth Science to Rob Van der Voo for his outstanding contributions to the field of paleomagnetism and his reconstruction of ancient continental positions that have lead to a better understanding of plate tectonic processes for the past billion years of Earth history.     

Van der Waals力场中束缚态粒子能级的数值方法和波函数

利用近似情况下Van der Waals力场中束缚态粒子的定态Schrodinger方程,研究束缚态粒子能级的数值方法和波函数,并讨论不同能量状态粒子的概率密度分布情况,计算经典禁区粒子出现的概率,产生了隧道效应。