Voltage distribution in growing conducting networks

We investigate by random-walk simulations and a mean-field theory how growth by biased addition of nodes affects flow of the current through the emergent conducting graph, representing a digital circuit. In the interior of a large network the voltage varies with the addition time s < t of the node as V(s) ∼ ln(s)/s ^θ when constant current enters the network at last added node t and leaves at the root of the graph which is grounded. The topological closeness of the conduction path and shortest path through a node suggests that the charged random walk determines these global graph properties by using only local search algorithms. The results agree with mean-field theory on tree structures, while the numerical method is applicable to graphs of any complexity. Received 26 August 2002 Published online 29 November 2002     

束晕-混沌的复杂性理论与控制方法及其应用前景

本文系统论述涉及强流加速器等强流离子束装置中产生的束晕-混沌的复杂性理论与控制方法及其应用前景。强流离子束在核材料生产与增殖、洁净核能、放射性废物嬗变、放射性药物生产、重离子聚变、高能物理、核科学与工程、国防与民用工业和医疗等许多方面都有极其重要的应用潜力和诱人的发展前景。尤其是，近年来强流加速器驱动的放射性洁净核能系统是国内外关注的热门课题，因为它比常规核电更安全、更干净、更便宜。但是，强流离子束形成的束晕-混沌的复杂性现象已引起了国内外广泛关注，需要加以抑制、控制和消除这类现象，解决这一难题已经成为强流离子束应用中的关键问题之一。目前不仅必须深入研究这类束晕-混沌的复杂特性及其产生的物理机制，而且需要研究如何实现对束晕-混沌的有效控制，并寻求和发展其新理论、新方法和新技术。这就向强流离子束物理和非线性-复杂性科学及其技术提出了一系列极富挑战性的新课题。本文结合国内外的研究概况，根据我们多年来的研究成果，特别是我们首创性地提出了一些束晕-混沌的有效控制方法，它们包括：非线性反馈控制法，小波反馈控制法，变结构控制法，延迟反馈控制法，参数自适应控制法等，进行重点的介绍。对上述课题当前的主要进展及相关问题进行系统的总结和比较全面综述的评论。最后，指出该领域今后的研究方向，以推动这个崭新领域的深入研究和应用发展。     

两部美国大学物理教材对我们教学改革的启示

介绍了美国两部大学物理教材的特点，分析了美国教材在教学内容、教学方法、教学手段现代化方面的特色，为我们的教学改革提供一些可供借鉴的经验。     

数量级在物理实验中的应用

介绍了数量级在物理实验设计、实验失败原因分析、误差分析及实验结果判断方面的应用．     

普通物理实验教学在重建认知结构中的特殊作用

运用教育学和心理学知识，通过典型的普通物理实验，分析了普通物理实验教学在重建认知结构中的特殊作用。     

Numerical study of chaotic oscillations in the electron beam with virtual cathode in the external non-uniform magnetic fields

In this Letter the results of theoretical investigations of the chaotic microwave oscillator based on the electron beam with a virtual cathode are presented. Nonlinear non-stationary processes in these electron systems are studied by means of numerical analysis of 2.5D model. It was discovered that the non-uniform external magnetic field value controls the dynamical regime of oscillations in the virtual cathode oscillator. The processes of the chaotization of output microwave radiation are described and interpreted from the point of view of the formation and interaction of electron structures (bunches) in the electron beams. The numerical results have shown that the investigated electron system with virtual cathode could be considered as a promising controlled source of wideband chaotic oscillations in the microwave range.     

用Auto CAD微机演示物理教学

本文介绍了利用AutoCAD软件演示物理教学的方法，可促进教学改革，提高教学质量。     

高校创新型科研团队行为模式研究——以生命科学部高校国家重点实验室为例

国家重点实验室作为高校创新型科研团队的"国家队",是我国基础研究的核心力量和重大创新成果的摇篮,更是培养高层次科技人才的基地.研究高校创新型科研团队组织分布、管理结构、团队成员组成、科研、学术交流等具体行为模式特征,将是进一步发展和完善高校创新型科研团队的有力切入点,也将为相关科研政策的改进和完善提供参考依据.     

多功能物理演示实验室的构建

本文结合东华理工大学物理演示实验室的建设实践,分析了物理演示实验室的教学辅助、科普教育和创新实践等教育功能,并提出了建设多功能物理演示实验室的思路。     

Photoionization of some closed shell atoms and ions

Dipole-allowed single photoionization of some closed shell atoms and ions has been investigated in the relativistic random-phase approximation (RRPA). Application of relativisticmultichannel quantum defect theory (RMQDT) is made together with RRPA to analyse autoionizing resonances. Analysis points to the importance of interchannel coupling in high energy photoionization and reveals various degeneracies in relativistic atomic spectra to influence the low energy dynamics. Interesting threshold behavior in photoelectron spin polarization has been seen. Prospective future studies have been indicated.