A Novel Method of Spectral Analysis of Oscillatory Belousov–Zhabotinsky Reaction

This paper is a preliminary study of time–frequency behavior of homogenous Belousov–Zhabotinsky reaction in a batch reactor. A series of measurements performed for a variable concentration of the reaction substrates led to the conclusion that there exists time-dependency of an instantaneous frequency of fundamental frequency and harmonics and of electrode potential fluctuations generated during the process discussed. The Short Time Fourier Transformation (STFT) was proposed for analyzing electrode potential registers. On the basis of STFT analysis a decrease in frequency of oscillations of exponential character has been postulated.     

基于提升格式的小波变换用于处理化学信号

将提升haar小波变换应用于对不同类型含高噪声化学信号的处理,提出1种用于高噪声化学信号中滤除噪声的快速新方法——提升小波滤噪法,并使之与重叠峰分辨技术联用;以优选的小波分解层数对低信噪比的分析化学信号进行基于提升格式的小波变换处理,取得满意的结果;方法简单、快捷、准确、易行．运算速度是传统小波变换的一半,对高噪声化学信号的处理结果信噪比提高几百倍,峰位置相对误差小于1．5％;应用于氨基酸体系毛细管电泳检测信号的处理,有效降低了实验噪声的影响,分辨提取了难以察觉的信号．结果峰形变窄,峰高增加．大大提高了峰的分辨率．验证和显示了方法的可行性和优越性。     

Fusion of 2-D SIMS Images Using the Wavelet Transform

 Secondary ion mass spectroscopy (SIMS) is a powerful method for element distribution examination of conducting and semi-conducting surfaces at high spatial resolution and with a high sensitivity. Routine surface analysis produces about 8 to 15 images in a short time, each of which displays the intensity distribution of one mass, thus generating a multispectral SIMS image. Formation of occlusions, segregations, and the overall location of the elements relative to each other, are difficult to recognise when looking at n separate 2-D images. Image fusion is a process whereby images obtained from various sensors, or at different moments of time, or under different conditions, are combined together to provide a more complete picture of the object under investigation. The process of combining SIMS images may be viewed as an attempt to compensate for the inherent effect of SIMS to channel the information obtained from the sample into different images, corresponding to different element phases. The wavelet transform is a powerful method for fusion of images. This work covers the use of wavelet based fusion algorithms on multispectral SIMS images, evaluating the performance of different wavelet based fusion rules on different type of image systems and comparing the results to conventional fusion techniques. An aim of this study is to increase the information, i.e. the number of masses, which can be merged into one image in order to enhance the perception and interpretation of the SIMS surface images.     

利用小波变换检测电化学噪声信号波形

简述了应用小波变换检测点蚀电化学噪声信号的基本原理,对在3.5％ NaCl溶液中工业纯铝发生点蚀的电化学噪声信号检测分析表明：小波变换能够提取发生点蚀的电化学噪声信号和测量系统噪声在多惊讶分辨空间中的波形特征,根据表征该特征的小波系数模极大值在不同尺度下的传播特性,可实现对点蚀电化学噪声信号波形的检测。     

Periodic Perturbation of Chemical Oscillators: Entrainment and Induced Synchronization

It is well known that a large number of catalyst‐carrying beads immersed in an oscillatory chemical medium (Belousov–Zhabotinsky reaction) display collective oscillatory behavior. Using a light sensitive version of BZ, we show that this collective behavior can be entrained to an external light source with an oscillatory intensity. Thus, the emerging collective behavior can be controlled by an external perturbation.     

利用二进样条小波模极大方法消除毛细管电泳信号噪声的研究

根据毛细管电泳信号中噪声与真实信号的模极大值特性之间存在较大差异的特点,提出了一种利用二进样条小波模极大值法去噪的方法研究了信号的半峰宽、不同信噪比以及阈值的选取对去噪结果的影响,并对模拟含噪信号和含噪毛经电泳信号去噪前后的结果进行了比较,实验结果表明,该法能效地消除谱带较宽的毛细管电泳等信号中存在的噪声。     

连续样条小波变换用于分解重叠峰的研究

以B-样条小波为分析小波,提出了用于分析化学重叠信号解析的新方法——连续样条小波变换,结果表明：连续样条小波变换应用于分析化学信号的处理,能使峰变窄同时还能提高信号的信噪比,是一种新型有效的重叠信号解析方法,能从含噪声重叠信号中直接得到重叠峰的峰数目及其相应的峰位置。     

二维小波变换与子窗口因子分析法结合用于含噪声HPLC-DAD数据的解析

将二维小波变换与子窗口因子分析法相结合,用于模拟的高噪声HPLC-DAD数据的解析.首先应用二维小波变换滤除噪声,然后采用子窗口因子分析法解析重叠峰.结果表明,信噪比为10的高噪声基本被滤除掉.     

一种基于二进小波变换的自适应滤波方法

根据信号和噪声经小波变换后在不同尺度上有不同的特征,将相邻尺度二进小波变换值的相关量进行归一化处理并与小波变换值比较来判断信号与噪声,以噪声在各尺度的方差作为终止迭代的标准,提出了一种基于二进小波变换小波域选择噪声的自适应滤波方法。研究了模拟信号的去噪过程、半峰宽和信噪比对去噪结果的影响,并对模拟含噪信号和含噪毛细管电泳信号去噪前后的结果进行了比较。实验结果表明：由于该方法具有良好的自适应性和显著的滤波效果,必将得到广泛的应用。     

基于离散小波变换的蛋白质结构、功能与进化关系延时交叉相关分析

基于氨基酸的疏水特性, 将离散小波变换与延时交叉相关分析相结合, 提出了一种分析蛋白质结构、功能和进化关系的新方法——序列小波层次相关法. 以丝氨酸蛋白酶超家族中Trypsin种属为研究对象, 描述了该方法在揭示不同物种的Trypsin蛋白质进化关系中的应用; 以蛋白质酪氨酸磷酸酶、血红蛋白和溶菌酶为例, 采用该方法揭示了蛋白质之间功能与序列的内在关系. 该方法为非参数方法, 具有简单、直观、可视和可操作性强等特点, 且不需要事先知道蛋白质的结构, 仅从蛋白质的氨基酸序列出发即可比较和揭示蛋白质之间的关系.     

小波变换与分析化学信号处理

介绍了小波变换的基本理论并对小波变换的常用算法和应用进行了评述。由于小波变换的时2频局部化性质, 使其成为信号处理的强有力工具。在分析化学领域中, 小波变换在流动注射分析、伏安分析、高效液相色谱、红外光谱、质谱、核磁共振谱、可见-紫外光谱、光声光谱、扩展X-射线吸收精细结构(EXAFS) 谱等分析化学信号的平滑滤噪、数据压缩、重叠信号解析等方面都有成功的应用。     

应用连续小波变换预测蛋白质的二级结构

将代码为lgca蛋白质的氨基酸序列映射为疏水值序列,在合适的尺度下,通过 连续小波变换法分别对其α螺旋,α螺旋和β折叠之间的连接多肽(即部分规则和无 规则二级结构)进行预测,准确率分别为76．5％和85．7％．从PDBsum数据库中随 机抽取100个蛋白质作为测试对象,其中全α螺旋、全β折叠、α／β以及α+β蛋 白质各25个．在100个蛋白质中共有1618个连接多肽和747个α螺旋.本法预测到的 连接多肽共有1536个,其中1308个与实际结构一致,平均预测准确率为85.2％;预 测到的α螺旋有770个,其中581个与实际结构一致,平均预测准确率为75．5％． 结果表明：该法可较好地预测蛋白质的α螺旋、连接多肽,具有极大的发展前景．     

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。     

小波变换与神经网络结合用于示波计时电位测定

小波变换与神经网络的结合是化学计量学中一个十分活跃的研究领域。作者介绍了小波变换与神经网络的两种结合方式——辅助式结合和嵌套式结合,并将二者用于单组分示波计时电位信号定量计算的比较。结果表明：辅助式结合训练次数少,预测误差小;小波神经网络计算的自动化程度高,计算结果明显优于传统的人工神经网络。     

Application of Embedded Zerotree Wavelet to the Compression of Infrared Spectra

In this paper the embedded zerotree wavelet (EZW) method and Huffinan coding are proposed to compress infrared (IR) spectra. We found that this technique is much better than others in terms of efficiently coding wavelet coefficients because the zerotree quantization is an effective way of exploiting the self-similarities of wavelet coefficients at various resolutions.     

小波变换法在X射线能谱去噪声中的应用

阐述了二进小波变换法的去噪声原理和方法,并将其应用于X射线能谱分析中噪声的去除。实验结果表明,该去噪方法能够解决传统平滑方法的滑方法的不足,改善X射线能谱的定性、定量分析结果。     

小波变换用于近红外光谱数据压缩

近红外光潜数据量大,需要较大数据存储空间和较长的建模时间、本文以成品柴油性质分析为例．将小波变换用于近红外光谱数据压缩处理,详细考察了小波压缩参数,比较了压缩前后潜图差异以及性质分析偏差的变化。研究结果表明．采用Daubechies小波函数(N=2)为母函数．进行3次分解,直接采用其逼近系数(Ca3)作为谱图压缩数据,其重构光谱与原始光谱基本一致直接利用逼近系数进行性质分析,其分析精度与原始光谱数据基本相当,存储空间减少至原来的1／8,且能够明显缩短其建模时间和分析时间。     

Chaos Synchronization in the Belousov—Zhabotinsky Chemical Reaction by Adaptive Control Scheme

The adaptive synchronization sc heme proposed by John and Amritkar was employed into the Belousov-Zhabotinsky（BZ)4-varibale-Montanator model system.By the parameter adjustment,chaos synchroniztion has been obtained ,Through calculating the transient time,the optimal combination of the stiffness constant and damping constant was obtained .Furthermore,the relationships among the transient time,conditional Lyapunov exponents,the stiffiness constant and damping constant were discussed ,Also ,the BZ system with the adaptive synchronization scheme might be used for the communication purposes.     

Discrete Fourier Transform Analysis of Chronoamperometric Currents Obtained Under Ultrasound

A discrete Fourier transform (DFT) technique was used to analyze chronoamperometric currents at a Pt microdisk electrode (Ø=15 μm) in an electrolyte containing [Fe(CN)₆]^3?/[Fe(CN)₆]^4? under ultrasound at a frequency of 26.3 kHz and the powers of 0–50 W. The currents were measured by a high‐speed data acquisition card. Considering the effects of acoustic vibrations and cavitations on the limiting currents, a microdisk electrode and a high frequency sampling (10 MHz) were used to collect the current signals to restrain the deviation of average from sampling period in other methods. The results show that the amplitudes at 0 Hz and 26.3 kHz are related to the decay of ultrasound at constant power output when the separation between sono‐horn and electrode increases, and also related to the reactant concentration at the same ultrasonic conditions. The frequency signals are always shown in frequency spectrum despite different ultrasonic conditions. The amplitudes reflect the intensity of ultrasound and the concentration of reactant in solution, so they can be called specific frequencies. This method can be used to analyze quantitatively the effects of ultrasound on electrochemical reaction, determine the reactant concentration and measure the distribution of ultrasonic intensity in a solution.