采用H2SO4-CH2(COOH)2-Ce2(SO4)3-KBrO3化学振荡体系,研究了中药赤芍的化学指纹图谱,并对温度、赤芍用量进行了考察,确定体系的最佳实验条件为12 mL 3.0 mol/L H2SO4溶液、6 mL 0.4 mol/LCH2(COOH)2溶液、3 mL 0.005 mol/L Ce2(SO4)3和3...采用H2SO4-CH2(COOH)2-Ce2(SO4)3-KBrO3化学振荡体系,研究了中药赤芍的化学指纹图谱,并对温度、赤芍用量进行了考察,确定体系的最佳实验条件为12 mL 3.0 mol/L H2SO4溶液、6 mL 0.4 mol/LCH2(COOH)2溶液、3 mL 0.005 mol/L Ce2(SO4)3和3 mL 0.2 mol/L KBrO3溶液,温度35℃、加入0.4 g的中药材粉末。通过对不同产地中药材赤芍(安徽亳州、山东菏泽、内蒙古赤峰、海拉尔)化学指纹图谱的研究,发现不同产地的中药材赤芍不仅具有明显不同的化学指纹图谱形状,而且主要参数也有很大区别。其中亳州赤芍的最高诱导时间较小(133.76 s),但振荡寿命最长(554.89 s);而海拉尔赤芍的诱导时间最长(214.17 s),但振荡寿命最短(237.11 s)。该化学指纹图谱可方便地用于不同产地中药材赤芍的区别和鉴定。展开更多
It is proved experimentally that the relaxation and complex electrochemical oscillations could be induced by inserting external resistors in the electrochemical systems in which bistability could be found.FeH2SO4 syst...It is proved experimentally that the relaxation and complex electrochemical oscillations could be induced by inserting external resistors in the electrochemical systems in which bistability could be found.FeH2SO4 system,in which the Fe electrode exhibited bistability within the potential range of 0.309 V～0.406V(vs.SCE),was chosen in our experiments.When the applied potential was 0.340 V and no external resistor was inserted,no oscillations could be observed.While the applied potential was kept at 0.340 V and an appropriate external resistor was connected in series to the electrochemical system,relaxation or complex oscillations appeared.Upon the external resistance increased,the amplitude of the oscillations decreased gradually.The inducement of electrochemical oscillations is helpful to understand the mechanism of the metals dissolution and passive,and to control the dynamic behavior of some electrochemical systems.展开更多
Dynamical model of coupled electrode BZ reaction system is established based on FKN mechanism and Oregonator model.Under certain conditions,the effect of electrode current on BZ electrochemical reaction system is disc...Dynamical model of coupled electrode BZ reaction system is established based on FKN mechanism and Oregonator model.Under certain conditions,the effect of electrode current on BZ electrochemical reaction system is discussed.By means of stability analysis of three-variable system,limit cycle oscillatory regime of the electrode reaction phase is calculated numerically.It turns out that limit cycle oscillation can appear in electrode phase under a fixed current when the bulk phase is at a steady state.Meanwhile,external electrode current can lead to non-synchronization of bulk phase and electrode reaction phase.展开更多
文摘It is proved experimentally that the relaxation and complex electrochemical oscillations could be induced by inserting external resistors in the electrochemical systems in which bistability could be found.FeH2SO4 system,in which the Fe electrode exhibited bistability within the potential range of 0.309 V～0.406V(vs.SCE),was chosen in our experiments.When the applied potential was 0.340 V and no external resistor was inserted,no oscillations could be observed.While the applied potential was kept at 0.340 V and an appropriate external resistor was connected in series to the electrochemical system,relaxation or complex oscillations appeared.Upon the external resistance increased,the amplitude of the oscillations decreased gradually.The inducement of electrochemical oscillations is helpful to understand the mechanism of the metals dissolution and passive,and to control the dynamic behavior of some electrochemical systems.
文摘Dynamical model of coupled electrode BZ reaction system is established based on FKN mechanism and Oregonator model.Under certain conditions,the effect of electrode current on BZ electrochemical reaction system is discussed.By means of stability analysis of three-variable system,limit cycle oscillatory regime of the electrode reaction phase is calculated numerically.It turns out that limit cycle oscillation can appear in electrode phase under a fixed current when the bulk phase is at a steady state.Meanwhile,external electrode current can lead to non-synchronization of bulk phase and electrode reaction phase.
