在线小波变换用于伏安分析仪的研制

将在线小波变换应用于伏安信号的在线处理,研制了具有小波变换功能的伏安分析仪。该系统利用在线小波变换对采集到所数据进行实时处理,具有控制灵活,分辨率高,数据处理方便等特点。通过对低浓度Ｃｙ＾２＋和Ｆｅ＾３＋混合样品的阶梯斜坡扫描伏安珠滤噪及定性,定量分析,结果表明可获得满意的分析结果。     

小波变换在差分脉冲伏安法数据处理中的应用

本文根据小波变换不改变信号线性关系的性质，用ＤＯＧ小波函数处理了Ｃｕ－ＫＮＯ３中Ｃｕ＾２＋的差分脉冲伏安法实验数据，结果延长了测定的线性范围。     

阶跃伏安法信号的样条小波分析

采用样条小波基处理低信噪比的阶跃伏安法离散数据。仿真实验和化学实验结果表明,样条小波分析含强白噪声的信号时,能保真地提取出有用信号,信噪比(S/N)降低至0.1～0.2.这种方法具有不需设置目标函数、窗口函数、初值估计等优点,同时运算简单、节省储存空间。因此,样条小波运用于信号分析较现行方法优越,并具有广阔的应用前景。     

小波变换用于示波信号中有用信息提取的研究

示波分析是近年来在我国发展起来的一个新的电化学分析研究领域［１～４］．它根据阴极射线示波器荧光屏上示波图及其变化进行分析测试,从原理上可以将其分为示波电位法和示波计时电位法;从测定方式上可以将其分为示波滴定和示波测定．关于示波电位法的一些理论问题（如...     

连续小波变换用于滴定终点的确定

针对基于二进小波变换奇异性检测方法的不足,提出基于连续小波变换奇异性检测方法,该方法具有较细致的局部奇异性刻画能力,能够对滴定曲线的滴定终点进行精确的定位。将这种方法应用于NaOH对HCl和H3PO4滴定曲线滴定终点的确定,取得了理想的结果。     

去卷积伏安法中离散数据处理的方法研究(Ⅰ)──正交小波变换平滑

一系列的离散数据处理方法已成为化学计量学的重要组成部分[1],去卷和伏安法就是结合计算机技术的新一代电分析方法,其激励信号与输出信号均为计算机发生和采集的数字信号,对采集到的信号一般采用移动平均法[2]和Fourier变换处理法[3]进行平滑处理．但是,Fourier变换在电分析化学领域的难度较大,运算复杂,为此,Aubarel等[4]提出了不用FFT的Fourier变换平滑算法,但是该法要先对信号进行预处理,并且对Fourier的和式要反复进行折叠,计算量较大．80年代末发展起来的小波变换引起了人们广泛的关注[5],被称为数学“显微镜”,具有…     

表面等离子体共振技术与循环伏安法联用检测甲苯胺蓝

将表面等离子体共振技术(SPR) 与循环伏安法(CV) 联用, 并用小波变换提取实验数据, 实现了甲苯胺蓝的定量检测. 以传感片上的金膜为SPR测量基底, 并作为电化学的工作电极, 以Ag/AgCl电极(饱和KCl) 为参比电极, 以铂丝为对电极, 同时进行SPR扫描和循环伏安法扫描, 发现电化学聚合导致甲苯胺蓝氧化峰峰电位正移, 还原峰峰电位不变, 而SPR响应也整体下降; 将SPR响应对电位求导后进而对电位作图, 经小波变换处理后, 发现波谱峰电位接近循环伏安法氧化还原法电位. 利用该方法检测甲苯胺蓝的检出限与采用循环伏安法检测甲苯胺蓝的检出限在一个数量级上.     

小波变换用于不同晶型聚丙烯红外特征峰的鉴别

本文运用小波变换研究了α晶相和β晶相聚丙烯的很相似的傅里叶变换红外特征光谱。经过小波变换后，这两种晶相聚丙烯的吸收光谱有显著的差别。结果表明聚丙烯的晶相可通过对其红外光谱进行小波变换而鉴别。     

一种基于小波变换的近红外化学指纹图谱分析方法

提出了一种快速无损的化学指纹图谱分析新方法. 根据小波变换多分辨分析的特点, 对近红外(NIR)光谱进行小波分解, 从中提取被测样品的化学特征信息, 并作数字信息可视化处理, 构建形成可直观识别样品模式特征的NIR指纹图谱. 将该方法用于中药材丹参的质量检测, 检测结果与色谱指纹图谱检测结果相符, 能快速有效地识别丹参质量模式间的差异, 有望发展成为一种快速分析检测天然产物质量的方法.     

快扫循环伏安曲线的单纯形优化-数值模拟拟合方法

采用Gl算法改进了快扫伏安曲线的数值模拟,提高了模拟计算的速度.使用单纯形优化-数值模拟方法,以电流、峰电位误差的加权值作为拟合参数的评价函数,对二茂铁在0,3mm直径铂盘电极上,不同扫速下的循环伏安图进行了拟合.在拟合过程中自动进行伏安图基线的校正,同时拟合出标准非均相速度常数k~0,未补偿溶液电阻R_u以及双电层电容C_(dl)等重要的参数值,所得k~0值与文献报道结果一致.     

用研磨电极研究Bi2O3的循环伏安行为

用研磨电极研究Bi2O3的循环伏安行为;微电极;氧化铋;循环伏安     

苯醌在银-汞(膜)微环电极上的循环扫描伏安波

首次报道采用化学镀法制作银－汞（膜）微环电极,并用于探讨苯醌的循环伏安曲线。还对伏安曲线的性质进行了详细的论述。结果表明：苯醌在Ｍｃｌｌｖａｉｎｅ缓冲液中的还原过程属地单电子可逆反应。根据不同扫描速度时还原波的峰电流值可以计算得到苯醌的扩散系数值。     

Signal Processing in Normal Pulse Voltammetry by Means of Dedicated Mother Wavelet

In the work, a new signal processing algorithm is presented and applied for the transformation of the sigmoidal shaped curves, registered in normal pulse voltammetry (NPV), to the peak shaped curves. The method is based on the continuous wavelet transform (CWT) and specially constructed mother wavelet defined using the ideal wave‐shaped curve. Transformation of the signal, elimination of noises and separation of overlapping data can be achieved in one step by means of proposed procedure. The operation and effectiveness of the algorithm is presented using ideal, noised and overlapping simulated curves. The process of simultaneous determination of lead and indium as well as transformation of curves registered for elements' ions: lead, indium, thallium and cadmium is described. The obtained results show substantial improvement of the performance of NPV.     

Analysis of Spontaneous Electrochemical Oscillations by the Wavelet Transformation Method

A new way of analyzing current oscillations that accompany anodic metal dissolution is presented. A wavelet transformation is used for separation and spectral analysis of singular courses—elementary components of electrochemical oscillation recordings. A method of obtaining oscillation energy distribution analogous to the spectral power density function is presented. It is shown that the chaotic component (Shil'nikov chaos) can be separated from the deterministic component of the described process.     

Development a New Method for the Determination of Chloropromazine in Trace Amounts by Fast Fourier Continuous Cyclic Voltammetry at an Au Microelectrode in a Flowing System

In this study a new technique has been developed for the determination of chloropromazine in flow‐injection systems. The technique, named fast Fourier transformation continuous cyclic voltammetry (FFTCV), basically illustrates the benefits of sensitivity, selectivity, simplicity and low detection limit. It is also important to refer to the positive points, presented only by the use of this technique. Firstly, it is no longer necessary to remove the oxygen from the test solution. Furthermore, the quick determination of any such compound in many chromatographic methods is possible. Thirdly, the corresponding detection limit is of sub‐nanomolar level. Additionally, a special computer based numerical method is also introduced for the calculation of the analyte signal and noise reduction. The electrode response was calculated in accordance with the partial and total charge exchanges on the electrode surface, after the background current subtraction from that of noise. The integration range of currents was set for all the potential scan ranges, including oxidation and reduction of Au surface electrode, to obtain a sensitive determination. The performed experiments aimed at measuring the effects of different parameters on the method sensitivity. In the end of these measurements, it was concluded that the method was linear for the concentration range of 0.32–31900 pg/mL (r = 0.996) with a limit of detection and quantitation 0.1 and 0.32 pg/mL, respectively. For the achievement of these optimum results, the parameter values were set to 100 V/s for the scan rate, 0.4 s for accumulation time, 800 mV for accumulation potential and 2 for the pH.     

多孔电极电池的循环伏安法模拟

锂离子电池的全电池建模模拟对现代新能源领域的发展至关重要。伪二维（P2D）电化学模型是最常使用的全电池模拟模型,但一直被用于输入为电流,输出为电压的模拟中。本文基于P2D模型,通过对内电位、电极电位以及电池端电压的详细讨论,首次采用电压边界条件,利用COMSOL仿真软件完成了实验中常用的两电极体系和三电极体系的循环伏安法建模和模拟。并对比分析了两/三电极体系中扫描速率、颗粒半径、电极锂扩散速率以及最大嵌锂浓度这四个参数对循环伏安曲线形状的影响。结果表明,循环伏安测试时扫描速率越大,循环伏安曲线的峰值电流越大;固相锂扩散速率越大、电活性颗粒半径越小、最大嵌锂浓度越大,峰值电流越大。在相同的测试条件下,三电极体系比两电极体系的循环伏安图对称性更好,电流响应更大,并且颗粒半径、锂扩散速率及最大嵌锂浓度这三个参数对峰值电流的影响也更为明显。     

Fast Fourier Continuous Cyclic Voltammetry at Gold Ultramicroelectrode in Flowing Solution for Determination of Ultra Trace Amounts of Penicillin G

In this work, for the first time a fast continuous cyclic voltammetry was used as a highly sensitive detection method for Penicillin G in a flow‐injection system. A special computer‐based numerical calculation method (using Fast Fourier Transformation) is introduced here for enhancing the analyte signal and noise reduction. During the measurements, the potential waveform (consists of potential steps for cleaning, stripping and potential ramp) was continuously applied on an Au disk microelectrode (with a radius 12.5 μm in radius). The stripping time was less than 200 ms. Effects of rest potential, sweep rate, and delay time on the sensitivity of the method were investigated. The limit of detection of the method was 1.0 × 10^?11 M. The detection limit of the method is 660 times lower than the most sensitive reported method. The relative standard deviation of the method at 1.0×10^?7 M of Penicillin G was 2.7% for 10 runs.     

聚对硝基苯偶氮间苯二酚修饰电极伏安法测定多巴胺

采用循环伏安法研究了多巴胺(DA)在聚对硝基苯偶氮间苯二酚(p-nitrobenzenazo resorcinol,简称NBAR)膜修饰电极上的电化学行为,用差示脉冲伏安法对多巴胺的含量进行测定.结果表明,聚NBAR膜修饰电极对DA有明显的电催化作用.在pH4.0的磷酸盐缓冲液中,氧化峰电流与DA浓度在5.0×10-6~8.0×10-4mol/L范围内呈良好的线性关系,检测限为6.0×10-7mol/L.修饰电极可有效消除针剂中其它组分对DA测定的干扰,已用于实际样品DA含量的测定,结果令人满意.     

基于迭代小波变换的光谱信号本底扣除方法研究

本底会对光谱分析结果产生很大的干扰作用,为获取特征峰的有效信息,必须首先去除本底。该文提出了一种基于小波变换的本底扣除算法,通过对光谱及后续光谱迭代进行小波变换,利用逼近系数估计本底,直到本底收敛。提出了判断多次估计的本底最大误差是否足够小的收敛准则。利用该算法去除本底后,即可进行特征峰信息的提取。分别利用仿真光谱和实验能量色散X射线荧光光谱对算法进行了验证,并与传统小波变换和多项式拟合法进行了对比。结果表明,该算法能够更准确扣除光谱本底,对其他光谱的本底扣除也具有借鉴意义。