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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Intermittencies and Related Phenomena in the Oxidation of Formaldehyde at a Constant Current
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Intermittencies and Related Phenomena in the Oxidation of Formaldehyde at a Constant Current

机译：恒电流下甲醛氧化的间歇性及相关现象

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In the galvanostatic oxidation of formaldehyde on Pt at 43℃, we have found type III intermittency (in the Pomeau-Manneville classification) as well as type I intermittency. Potential oscillation patterns change with time, and type I intermittency is usually observed after a periodic oscillation in a sequence of periodic oscillations, which appear in decreasing order of their periods and are interposed between chaotic states. At a comparatively low current density (e.g., 0.23 mA cm↑(-2) or less for a 1 mol dm↑(-3) formaldehyde solution) in a solution with a formaldehyde concentration of 1 mol dm↑(-3) or more, we observe type III intermittency before a periodic oscillation in the sequence. Under other conditions we observe a type-III-like intermittent pattern followed by a reverse period-doubling cascade. We confirm the characteristics of type III intermittency with a period-k laminar flow by the shape of kth and (2k)th return maps, by the relation between a laminar duration and the time from the period-k pattern, and by the relation between a maximal Lyapunov exponent and that same time. Here we regard time as a parameter related to some surface states. We also observe that type I and type III intermittencies coexist. We sometimes observe a randomly alternating sequence of period(n+l) and period-n patterns without any intermittencies. When the sequence of periodic oscillations appear in increasing order of their periods, the order in which type I and type III intermittencies appear is also reversed.
机译：在43℃下Pt甲醛的恒电流氧化中，我们发现了III型间歇性（在Pomeau-Manneville分类中）和I型间歇性。潜在的振荡模式会随时间而变化，通常会在一系列周期性振荡的周期性振荡之后观察到I型间歇性，这些周期性振荡以其周期的降序出现并且介于混沌状态之间。在甲醛浓度为1 mol dm↑（-3）或更高的溶液中以相对较低的电流密度（例如，对于1 mol dm↑（-3）甲醛溶液为0.23 mA cm↑（-2）或更低） ，我们在序列中的周期性振荡之前观察到III型间歇性。在其他条件下，我们观察到类似III型的间歇模式，然后是反向周期加倍的级联。我们通过第k个和第（2k）个返回图的形状，层流持续时间与从周期k模式开始的时间之间的关系以及之间的关系来确定周期为k的层流的III型间歇性的特征一个最大的Lyapunov指数，并且同时。在这里，我们将时间视为与某些表面状态相关的参数。我们还观察到I型和III型间歇性并存。我们有时会观察到周期（n + 1）和周期n模式的随机交替序列，没有任何间歇性。当周期性振荡的序列按其周期的递增顺序出现时，I型和III型间歇性出现的顺序也将颠倒。

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