自催化三分子模型内噪声随机共振

The stochastic resonance in chemical reaction systems has recently attracted growing attentions. Using chemical Langevin equation,the effect of internal noise has been studied on the dynamical behavior of a single and a one-way coupled cubic autocatalator. For the single system,it is found that the internal noise can induce sustained oscillations,and the signal-to-noise ratio（SNR）undergoes a maximum with the variation of the system size. For the coupled system,the SNR passes through a maximum with changing coupling strengths as well as with changing system sizes,which demonstrates the occurrence of the internal noise stochastic resonance（INSR）and optimal size effect. In the presence or absence of influx into the system,the coupling enhanced or suppressed INSR is found in the coupled system. All cells of the coupled system appear to exhibit INSR at an approximately equal size at a suitable coupling strength,implying that the optimal system size and coupling strength can make the system reach an optimal chemical reaction state.     

阳极溶解电化学振荡体系中白噪声诱导随机共振的模拟

通过对电化学阳极溶解振荡模型加白噪声后引发的随机共振现象的模拟研究发现,在该体系的周期二振荡态时呈现显性内信号随机共振现象。当白噪声加在该电化学体系的周期二振荡态时,内信号的信噪比随着噪声的增大达到了最大值。同样噪声强度情况下,强信号的信噪比增加比弱信号的增加更加迅速。如果同时改变噪声强度,体系的信号频率也维持不变。研究表明,噪声对内信号的优化具有选择性,而体系的内信号也具有抵抗噪声和维持内在机制不变的性质。     

纳米尺度钯粒子表面一氧化碳氧化反应内噪声随机共振

在随机模型的基础上, 运用化学Langevin 方程、Poisson近似和精确随机模拟方法, 研究了内噪声对纳米(nm)尺度钯(Pd)粒子表面上一氧化碳(CO)催化氧化反应的影响. 在这类介观体系中, 由于显著内噪声的存在, 化学反应速率振荡具有随机性. 研究发现, 对于给定的CO偏压, 随着内噪声强度的改变, 随机振荡强度经过一个极大值, 从而证明了内噪声随机共振的存在. 这一现象表明, 合适的内噪声有利于反应速率振荡. 这种内噪声随机共振行为对外界参数(如CO偏压)具有稳定性(robust).     

细胞内钙离子体系中的双参数内信号随机共振

自从Benzi等于1981年提出随机共振(SR)现象以来,它已经受到物理、化学和生物学等领域的关注．SR是非线性体系中弱外信号和环境扰动之间的协同作用．后来胡岗等发现外信号可以由体系的内信号所代替,此时出现的SR被称为内随机共振(ISR)．通常对SR的研究都集中在外信号和噪音扰动参数上,如电压、电流和压力等．     

钙离子体系中隐式和显式内随机共振

近年来, 细胞内钙离子信号及其产生机理已成为研究热点之一, 这是因为钙离子信号能控制细胞的生死、 传递细胞间的信息、 提高基因表达的有效性和特殊性[^1~3]. 在钙离子信号传递过程中, 受环境扰动是不可避免的. Shuai等^[4]发现噪音能够控制钙离子通道中钙离子的释放. 在过去的十年中, 无论是物理、 化学还是生物体系^[5~10]的噪音效应已被广泛研究, 其中包括对随机共振(SR)的研究^[5], 经典SR是环境噪音能够放大弱的外加信号. 但随着研究的深入, 发现有无噪音SR^[11]和内SR(ISR) ^[6]. ISR的内信号来自噪音诱导的内信号, 这种SR现象叫隐式内SR(IISR). 而我们则发现了另外一种内SR, 即显式内SR(EISR) ^[12], 它的内信号是体系固有的内信号, 而不是由噪音诱导的. 本文主要研究加入外信号将对IISR和EISR产生的影响.     

噪声性质对B-Z流动反应体系随机共振影响的模拟

用一个三变量的B-Z流动反应模型研究当流速参数kf在Hopf分岔点附近被色噪声和白噪声调制后系统动力学的行为. 通过计算机模拟观察到噪声诱导的振荡以及随机共振(stochastic resonance)现象, 以及色噪声的相关时间和白噪声的持续时间对随机共振行为的影响.     

化学体系随机共振现象的理论研究

化学体系中随机共振现象的特性、机理、本质和应用的研究是非常重要的前沿课题。综述中国科学技术大学非线性化学实验室,在化学体系随机共振现象的理论研究中,所取得的主要成果,并阐述化学体系随机共振现象研究中所提出来的若干重要问题：非均相化学体系中随机共振;化学体系中内信号随机共振;化学体系中多重随机共振;化学体系中随机共振的调制;化学体系中色噪声作用下的随机共振;化学体系中时空随机共振;耦合化学体系中随机共振;化学体系中双参量随机共振。     

IO3--AsO33-化学反应中的随机共振

通过计算机模拟,在IO3--AsO33-化学双稳体系中,对反应控制参量加入周期信号和高斯噪声,体系由于信号和噪声的作用发生上下态之间相互跃迁.计算输出时间序列的功率谱,发现信号在噪声的作用下被放大,在某一最佳噪声强度下,存在一个最大的信噪比输出,表现出随机共振的特征.     

内噪声作用下的随机共振算法对弱信号的检测

基于随机共振理论提出了一种简便、有效地检测弱信号的方法。在内噪声协同作用下，通过调节输入噪声信号的大小能较好地提高系统输出信号的信噪比，从而实现检测背景噪声很强的弱信号的目的。应用于模拟信号和实验信号的结果证明了方法是可行的。     

耦合生物细胞体系中内噪声对检测弱刺激的积极作用

By constructing a mesoscopic stochastic model for intracellular calcium oscillations in coupled cell system, we investigated the influence of internal noise on the detection of weak stimulation using the chemical Langevin equation (CLE). We found that an optimal cell size V existed for a coupled cell chain length N and an optimal value of N existed for a given cell size V. At these values, the collective calcium oscillations showed the best performance, indicating the occurrence of“system size resonance (SSR)”or“internal noise stochastic resonance (INSR)”. And such a phenomenon was robust to the coupling strength. Living cells may have learned to exploit the internal noise to detect weak stimulation via the mechanism of INSR, and then encode information to specifically regulate distinct cellular functions. It is interesting to note that the optimal cell size is always present at V抑103 μm3, which is close to the real living cell size in vivo. Since the internal noise in living systems can not be ignored and the systems may often encounter weak stimulations, our findings might have significance for stimulation detecting processes in living systems.     

海洛因对别洛索夫-扎鲍京斯基振荡化学反应的影响及其分析应用

研究了海洛因对Belousov Zhabotinsky(B Z)振荡反应的影响 ,结果表明 :海洛因的加入明显地改变了振荡体系的周期和振幅 ,即对振荡体系产生扰动 ,扰动的浓度范围为 1.8× 10 -8～ 2 .1× 10 -3 mol/L ,且海洛因的浓度分别在 3.8× 10 -6～ 2 .8× 10 -5mol/L和 0 .9× 10 -6～ 2 .9× 10 -5mol/L范围内与振荡周期改变值ΔT和振幅改变值ΔA均呈现良好的线性关系 ,相关系数分别为 0 .9931和 0 .974 6。据此 ,建立了测定海洛因的新方法。     

Entropy Production along Dominant Pathway of Nonequilibrium Phase Transition in Mesoscopic Chemical System

We consider a bistable mesoscopic chemical reaction system and calculate entropy produc- tion along the dominant pathway during nonequilibrium phase transition. Using probability generating function method and eikonal approximation, we first convert the chemical master equation into the classical Hamilton-Jacobi equation, and then find the dominant pathways between two steady states in the phase space by calculating zero-energy trajectories. We find that entropy productions are related to the actions of the forward and backward dominant pathways. At the coexistence point where the stabilities of the two steady states are equiv alent, both the system entropy change and the medium entropy change are zero; whereas at non-coexistence point both of them are nonzero.     

A Novel Oscillating Chemical Reaction Using Ninhydrin as Single Organic Substrate

Nonlinear chemistry has been a focus in recent years1. Many chemical oscillating reactions have been found and studied intensively, such as Belousov-Zhabotinskii (BZ) reaction2, Briggs-Rauscher reaction3, peroxidase-oxidase4, Bray-Liebhafsky reaction5 and…     

苯酚的敞开体系化学振荡反应动力学法测定

利用KBrO3-Ce(SO4)2-Ch2(COOH)2-H2SO4敞开体系研究测定黄河水中苯酚污染物的新方法,在连续搅拌反应器（CSTR）中,当[KBrO3]=0.0625mol/L,[CH2(COOH)2]=0.187mol/,[Ce(SO4)2]=0.002mol/,[H2SO4]=0.8mol/L,蠕动泵单路流速为1.2mL/min时,苯酚的质量浓度在0.10-25mg/L范围内与振幅的改变、周期的改变呈线性关系,检出限为0.05mg/L;苯酚的加标回收率为95%-102%。