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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Temporal and Spatial Organization of Chemical and Hydrodynamic Processes.The System Pb~(2+)-Chlorite-Thiourea
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Temporal and Spatial Organization of Chemical and Hydrodynamic Processes.The System Pb~(2+)-Chlorite-Thiourea

机译：化学和水动力过程的时空组织Pb〜（2 +）-亚氯酸盐-硫脲体系

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Precise spatio-temporal organization of chemical,hydrodynamic,and mechanical processes is typical for biological systems where particular chemical reactions have to accrue in precisely assignment place and time.It is rarely studied and observed in chemical systems.We report unusual precipitation pattern formation of PbSO4 in chemical media(Pb~(2+)-Chlorite-Thiourea System).We have found that there is a region in a plane of initial concentrations of chlorite ions and thiourea where precipitation of lead sulfate appears in a form of ring if a pellet of lead nitrate is placed into the system.The whole process may be divided into three stages:movement of first circular front of lead containing solution,formation of a ringlike pattern of lead sulfate,and finally,propagation of this pattern resulting in a formation of ring with final inside diameter.Our experiments indicate that the following values are reproducible and quantify the PbSO4 ring evolution:induction time,radius of the ring birth,speed of ring propagation toward the center,and final inside radius of the ring.Numerical solution of kinetic equations allowed us to give a qualitative explanation for the phenomenon observed.Formation and evolution of the PbSO4 rings are caused by interplay of concentration gradients in the system and chemical reactions that occur in excitable chlorite-thiourea system.Chemical reactions and hydrodynamic processes form a complex causal network that made morphogenesis of this unusual pattern possible.
机译：在生物系统中，化学，流体动力学和机械过程的精确时空组织是典型的生物系统，其中特定的化学反应必须在精确的分配位置和时间进行。在化学系统中很少进行研究和观察。在化学介质（Pb〜（2 +）-亚氯酸盐-硫脲系统）中，我们发现在亚氯酸根离子和硫脲的初始浓度平面中存在一个区域，如果沉淀为小球，则硫酸铅沉淀会以环的形式出现整个过程可分为三个阶段：含铅溶液的第一个圆形前沿的移动，硫酸铅的环状图案的形成，最后该图案的传播导致形成铅。实验表明，以下数值是可重现的，并量化了PbSO4环的演化：诱导时间，环比半径h，环向中心传播的速度以及环的最终内半径。动力学方程的数值解使我们能够对观察到的现象进行定性解释。PbSO4环的形成和演化是由浓度梯度的相互作用引起的。在可激发的亚氯酸盐-硫脲系统中发生的系统和化学反应。化学反应和流体动力学过程形成了复杂的因果网络，这使得这种异常模式的形态发生成为可能。

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