外控弱周期电流约束下电极B-Z反应体系中的时间自组织

The coupled dynamical model consisting of the electrode B-Z system, and its related bulk phase B-Z system externally controlled by a periodical current is proposed on the basis of the Oregonator model. Dynamical behaviors of the electrode B-Z system, when subjected to external current constraint have been investigated systematically under the condition that the bulk phase is at a steady state. Furthermore, by means of the analytic method of slow manifold the regimes favorable to the appearance of limit-cycle oscillation have been determined on both the current~concentration of BrO3- and the current~model parameter plane respectively. The results are similar to those of experiments controlled externally by weak-periodical potential constraint, as reported in former works. It turns out that a limited cycle oscillatory regime degenerates under external periodical current constraint. Meanwhile, a kind of forced oscillations emerges in the regime where limit-cycle oscillations can t appear under constant current constraint.     

Self-Organization and Phase Transition in Two-Dimensional Traffic-Flow Model

An analytical investigation is made on two-dimensional traffic-flow model with alternative movement and exclude-volume effect between right and up arrows. Several exact results are obtained, including the upper critical density above which there are only jamming configurations, and the lower critical density below which there are only moving configurations. The observed jamming transition takes place at another critical density p_c(N), which is in the intermediate region between the lower and upper critical densities. This transition is suggested to be a second-order phase transition, the order parameter is found. The nature of self-organization, ergodicity breaking and synchronization are discussed. Comparison with the sandpile model is made.     

Light-Driven Flipping of Azobenzene Assemblies—Sparse Crystal Structures and Responsive Behaviour to Polarised Light

For creation of autonomous microrobots, which are able to move under conditions of a constant environment and a constant energy supply, a mechanism for maintenance of mechanical motion with a capacity for self-control is required. This requirement, known as self-organisation, represents the ability of a system to evade equilibrium through formation of a spatio-temporal pattern. Following our previous finding of a self-oscillatory flipping motion of an azobenzene-containing co-crystal, we present here regulation of the flipping motion by a light-receiving sensor molecule in relation to the alignment and role of azobenzene molecules in crystals. In the anisotropic structure, a specific azobenzene molecule acts as a reaction centre for the conversion of light to a mechanical function process, whereas the other molecules act as modulators for spatio-pattern regulation. The present results demonstrate that autonomously drivable molecular materials can exhibit information-responsive, self-sustainable motion by incorporating stimulus-responsive sensors.     

Density behaviors of Ge nanodots self-assembled by ion beam sputtering deposition

Self-assembled Ge nanodots with areal number density up to 2.33×1010 cm-2 and aspect ratio larger than 0.12 are prepared by ion beam sputtering deposition. The dot density, a function of deposition rate and Ge coverage, is observed to be limited mainly by the transformation from two-dimensional precursors to three-dimensional islands, and to be associated with the adatom behaviors of attachment and detachment from the islands. An unusual increasing temperature dependence of nanodot density is also revealed when a high ion energy is employed in sputtering deposition, and is shown to be related to the breaking down of the superstrained wetting layer. This result is attributed to the interaction between energetic atoms and the growth surface, which mediates the island nucleation.     

多个体系统的自组织行为

考虑了一类具有简单吸引排斥函数的多个体系统的离散模型,研究了多个体系统的群体聚集.特别地,我们证明了个体均集聚并在有限时间内形成一个团簇,这个团簇的大小仅取决于模型参数.     

Complexity and information: Measuring emergence,self-organization,and homeostasis at multiple scales

Concepts used in the scientific study of complex systems have become so widespread that their use and abuse has led to ambiguity and confusion in their meaning. In this article, we use information theory to provide abstract and concise measures of complexity, emergence, self-organization, and homeostasis. The purpose is to clarify the meaning of these concepts with the aid of the proposed formal measures. In a simplified version of the measures (focusing on the information produced by a system), emergence becomes the opposite of self-organization, while complexity represents their balance. Homeostasis can be seen as a measure of the stability of the system. We use computational experiments on random Boolean networks and elementary cellular automata to illustrate our measures at multiple scales. © 2012 Wiley Periodicals, Inc. Complexity, 2012     

基于动态结构模型的两轮机器人平衡控制研究

针对无监督学习网络模型对于特定的映射空间,期望产生特定的影响具有一定的局限性,提出了有监督的可生长结构的动态结构模型;该模型将动态结构模型与径向基函数网络结构有机结合,采用的是需要时生长的自组织生长算法,通过插入新的神经元、改变竞争层神经元间的连接以及调整层与层的连接权值,达到模型输出的精度要求,有效地解决了在输入特定的网络数据时,能产生期望的输出;该模型应用于两轮平衡机器人的平衡控制,经过仿真实验表明,该动态结构模型能够实现对两轮平衡机器人的平衡控制,且有一定的抗干扰性和实用价值。     

非链式化学HF(DF)激光器工作气体中电子分离的非稳定性和气体放电等离子体的自组织现象(英文)

报道了放电引发的非链式HF(DF)激光器中的激活介质由电子碰撞负离子分离引起的电离非稳定性。这种非稳性出现在电极空间分离、脉冲CO2激光加热的基于SF6的混合气体的大体积放电中。实验研究了自引发体放电过程中由激光加热引起的放电等离子体的自组织现象以及由此在放电间隙的大部分区域形成的准周期等离子体结构。重点分析了等离子体结构随气体温度和注入能量的变化,讨论了等离子体自组织对电子碰撞分离不稳定性所产生的影响,解释了混合气体中由于电子碰撞使负离子消失导致的单等离子体通道移动的产生机理。