偏振态的高速实时测量方法的研究

偏振态的测量在光通信领域有着重要的作用,因此越来越受到人们的关注。在分析现有方案的基础上,推导出了新的斯托克斯计算公式,以此公式为依据提出了一种能对高速变化的偏振态进行实时测量的新方案,并对可能产生的误差因素进行了分析。给出了制作实用化测量模块所要达到的器件要求和制作工艺。     

Noise-induced bistable switching dynamics through a potential energy landscape

Interlinked positive feedback loops,an important building block of biochemical systems,can induce bistable switching,leading to long-lasting state changes by brief stimuli.In this work,prevalent mutual activation between two species as another positive feedback is added to a generic interlinked positive-feedback-loop model originating from many realistic biological circuits.A stochastic fluctuation of the positive feedback strength is introduced in a bistable interval of the feedback strength,and bistability appears for the moderate feedback strength at a certain noise level.Stability analysis based on the potential energy landscape is further utilized to explore the noise-induced switching behavior of two stable steady states.     

Bifurcations and excitability in the temperature-sensitive Morris–Lecar neuron

Nonlinear Dynamics - The neuronal excitability related to the transition between firing and resting states is a basic and important dynamic behavior which has different bifurcation characteristics...     

Synthesis and Anti‐tumor Evaluation of B‐ring Modified Caged Xanthone Analogues of Gambogic Acid

Gambogic acid (GA, 1 ), the most prominent member of Garcinia natural products, has been reported to be a promising anti‐tumor agent. Previous studies have suggested that the planar B ring and the unique 4‐oxa‐tricyclo[4.3.1.0^3,7]dec‐2‐one caged motif were essential for anti‐tumor activity. To further explore the structure‐activity relationship (SAR) of caged Garcinia xanthones, two new series of B‐ring modified caged GA analogues 13a – 13e and 15a – 15e were synthesized utilizing a Claisen/Diel‐Alder cascade reaction. Subsequently, these compounds were evaluated for their in vitro anti‐tumor activities against A549, MCF‐7, SMMC‐7721 and BGC‐823 cancer cell lines by MTT assay. Among them, 13b – 13e exhibited micromolar inhibition against several cancer cell lines, being approximately 2–4 fold less potent in comparison to GA. SAR analysis revealed that the peripheral gem‐dimethyl groups are essential for maintaining anti‐tumor activity and substituent group on C1 position of B‐ring has a significant effect on potency, while modifications at C‐2, C‐3 and C‐4 positions are relatively tolerated. These findings will enhance our understanding of the SAR of Garcinia xanthones and lead to the development of simplified analogues as potential anti‐tumor agents.     

有限覆盖定理的教学研究与实践

介绍有限覆盖定理的教学方法,强调如何将无穷问题转化为有限问题的思想方法在一些理论问题中的应用.     

Memristive magnetic coupling feedback induces wave-pattern transition

Nonlinear Dynamics - In this paper, we design a memristive system involving magnetic coupling with time-delayed feedback. In a way of autaptic connection, the memristive magnetic coupling feedback...     

The effect of diffusion on the permanence of Smith population model in a polluted patch

IntroductionThe effect of diffusion on the permanence of population has been studied in some refer-ences. LevinI1] set up the followiIlg model to study the effect of diffusion on the permanence ofpopulation:: f \' \ =.tvhere ur(t) defines the number of population i in patch p, uu = (ut,'. u:). f,u(uu) isthe int!.i11sic growth rate fOr population t, and D:' is the (1iffosive rate of population l frompatch 7 to patch U. Hastingsi2J proved that the positive equilibrium state is stab1e for suf…     

Complex dynamics of compound bursting with burst episode composed of different bursts

Episodic or compound bursting arises from a transition between a burst episode composed of a long burst and several short bursts and a relatively long subthreshold oscillation in this work. The minimal and generic phantom bursting model proposed by Bertram et al. is employed to produce compound bursting of a single pancreatic ??-cell and compound bursting synchronization with antiphase spikes of two electrical coupling pancreatic ??-cells. Two different fast/slow analysis for the moderate and the slower slow variables in three-dimensional spaces are combined to highlight better how these two slow variables with different time scales commonly or separately result in complex dynamic of the compound bursting of both the single ??-cell and the two electrical coupling ??-cells. For the compound bursting synchronization with antiphase spikes, we reveal how varying coupling strength leads to a change of the number of short bursts within the burst episode for different types of compound bursting.