Computer-aided analysis of infrared, circular dichroism and absorption spectra

Marquardt and Powell optimization methods without constraints on the optimized spectral parameters were employed for decomposition of complex i.r., c.d. and absorption spectra into component bands. The procedure resolved experimental spectra into eight component bands and it can be easily adjusted for a larger set of component bands. The CPU time required for achievement of satisfactory convergence of parameters for eight component bands is rather large even when using mainframe computers and therefore division of spectra into a few non-overlapped parts is advisable. The program also can be used for calculation of absorption, c.d. and difference spectra from formatted raw spectral data.     

天然糖甙类化合物^13C—NMR位移范围规律的计算机解析方法

本文从糖甙类化合物的数据特点出发,用较严格的数学推导总结出原则上适用于任何类型的~(13)C-NMR 图谱化学位移范围规律计算机自动解析的方法,并从多方面说明了该方法的研究及实现对实际的~(13)C-NMR 图谱解析工作的意义和重要作用。     

Simultaneous determination of thorium and uranyl ions by optode spectra and chemometric techniques

A sensitive optode was fabricated from a recently synthesized ligand (triazene-1,3-di(2-methoxyphenyl)). Simultaneous determination of thorium and uranium in aqueous samples were performed by this optode in conjunction with partial least squares (PLS) and artificial neural network (ANN) techniques. The measured absorbances at 27 selected wavelengths were used for training. A PLS1 model with 4 and 3 latent variables for thorium and uranium respectively, a PLS2 model with 4 latent variables and a principal component ANN model (4-2-2) with linear transfer function after hidden and output layers were created. Relative error of prediction for PLS1, PLS2 and ANN models in synthetic mixtures were 7.40%, 7.12% and 5.04% respectively.     

Concentration determination of gas by organic thin film sensor and back propagation network

In this work, vacuum deposited thin films of PbPc, NiPc, VOPc, TiOPc and CoPc were employed as gas sensor to detect NO₂ and NO. Data collected from sensor responses were used to train a back-propagation network (BPN) for identifying the gas species and quantifying its concentration. The results show that among the metallophthalocyanines tested, PbPc and NiPc have better sensing characteristics towards NO₂ and NO. In BPN training, maximum error occurs for data collected by the TiOPc sensor, and minimum error occurs for array of PbPc and NiPc sensors. In the concentration prediction of NO or NO₂, the maximum predicted error is 6.94%. When Two-Stage BPN or Single-Stage BPN was use to identify and quantify a single gas (NO₂ or NO), the accuracy of recognition approaches 100% and the maximum error for concentration prediction is 7.45%.     

偏最小二乘法同时测定食醋的有效成分和防腐剂的含量

偏最小二乘方法建立近红外光谱与组分浓度的多元校正模型,用于同时快速测定食醋的有效成分(总酸)和防腐剂(苯甲酸)含量。采用透射模式,样品不经任何处理测定近红外光谱。用17个食醋样品建立偏最小二乘法(PLS)模型,用3个样品作为预测样品以评估PLS模型。结果:食醋中的总酸和苯甲酸在2 125～2 325 nm区域之间,与光谱有良好的线性关系,总酸的PLS模型中,隐变量为3时,预测均方根误差0.038 7 g·L~(-1),总酸含量与光谱的线性相关系数达到0.999 7,相对预测误差5.89%;苯甲酸的PLS模型中,隐变量为6时,预测均方根误差降至0.013 8 g·L~(-1),苯甲酸含量与光谱的线性相关系数达到0.999 8,相对预测误差降至4.29%。     

α-唑基-α-芳氧烷基频哪酮(芳乙酮)及其醇式衍生物抗真菌活性的分子筛选

研究了最佳投影识别法（Optimal Projection Recognition Method）在α－唑基－α－芳氧烷基频哪酮（芳乙酮）及其醇式衍生物抗真菌活性筛选中的应用，解决了由计算机自动搜索该类化合物活性分类的最佳模式识别分类图的问题，且得到了识别该类化合物高抗真菌活性的判据，据以筛选出了可望具有较高抗真菌活性的该类新化合物。     

Rapid determination of soil organic matter content based on soil colour obtained by a digital camera

ABSTRACT

Soil organic matter (SOM) is an important component of soil and a significant criterion in determining the dynamics of soil quality. A rapid, low-cost method to measure SOM content is needed to support the development of precision agriculture. This article studied the quantitative relationship between SOM and soil colour using a digital camera, which is relatively inexpensive and easy to operate, as a portable tool for obtaining colour information of the soil surface. The results show that mixed samples with different soil particle sizes reduce the noise of the image and are more suitable than uniform soil samples for predicting the SOM. Among the three bands of red, green, and blue (RGB), the red band had the best correlation with SOM, and its reciprocal correlation coefficient (r) reached 0.75. The reciprocal regression model of the RGB colour model provided good prediction results for mixed soil samples, with a coefficient of determination (R²) of 0.76 and a root mean square error (RMSE) of 0.55, and the validation result had an excellent predictive ability (R²_val = 0.85 and RMSE_val = 0.53). The single-variation predictive model of CIELa*b* colour space model through transformation of the RGB colour space model performed well. The model built by colour intensity values had a strong stability and forecasting capacity. Thus, a digital camera can be used as an alternative tool to rapidly measure SOM.     

Excel软件应用于测定配合物组成和稳定常数

配合物的稳定常数是重要的物理参数,用分光光度法测定稳定常数牵涉到大量的数据,图形和复杂计算,本文利用Excel软件的绘图和数据运算功能,绘制吸光度-波长曲线,绘制、校正吸光度.摩尔分数曲线以确定配合物组成.用其公式可示和迭代计算功能求出配合物的稳定常数,免除手作或编程的麻烦,处理数据变得简便,快捷,准确.     

Application of artificial neural networks to solve problems of identification and determination of concentration of salts in multi-component water solutions by Raman spectra

In this paper, the results of elaboration and comparative analysis of approaches concerned with application of neural network algorithms for effective solution of problem of pattern recognition (inverse problem with discrete output) along with inverse problem with continuous output are presented. Consideration is carried out at the example of problem of identification and determination of concentrations of inorganic salts in multi-component water solutions by Raman spectra. The studied approach is concerned with solution of both problems (classification and determination of concentrations) using a single neural network trained on experimental or quasi-model data.     

在线拉曼光谱仪测定粗汽油中芳烃各组分含量的研究

基于在线拉曼光谱仪,采用拉曼光谱和化学计量学法,结合偏最小二乘(PLS)法,通过一定数量的芳烃样品进行实验,建立了快速、准确测定粗汽油产品中芳烃的仿真模型,计算芳烃各组分在粗汽油样品中的体积分数。实验数据表明:拉曼光谱结合PLS模型与传统检测方法相比,具有分析速度快、准确性高、重复性好等特点,可以在一定程度上替代传统的色谱检测,在实际生产中有极为广泛的应用。     

吸附溶出伏安法在环境检测和药物分析中的应用与进展

吸附溶出伏安法能够测量许多用通常电化学溶出分析难以定量的痕量金属和有机物,并以其灵敏、简单、廉价等特性在环境检测和药物分析中大受欢迎,它是以非电解过程将待测物吸附到工作电极上后,再进行伏安扫描.该文总结了近年来国内外对吸附溶出分析法的研究进展及在环境检测和药物分析中的应用.     

Observability and determination of surface temperature Part 1

The problem of determining the surface temperature of a thin rod and thin rectangular plate from temperature readings at interior points is investigated. It is shown that this problem can be solved by an infinite differentiation operator acting on the known temperature readings. Examples are also obtained which show that the surface temperature cannot be determined by a discrete set of temperature readings; this is in contrast to the recent discrete observability results obtained for the determination of initial temperature.     

A program for determination of composition and thermodynamics of the ideal gas-phase equilibrium isomeric mixtures

A FORTRAN program is described for the evaluation of populations of isomers in their ideal gas-phase equilibrium mixture, based on molecular parameters and energetics as input information for the construction of individual partition functions, as well as for the evaluation of the recently introduced isomerism contributions to overall thermodynamics. The program is particularly useful for the evaluation, interpretation or prediction of the behaviour of complex isomeric mixtures, under a full consideration of details of vibrational motions.     

Personal computer-based direct synthesis of optimum rectangular waveguide E-, H-, and EH-plane transformers

In this work a direct synthesis technique is presented for the optimum design of rectangular waveguide continuous and stepped impedance transformers. The synthesis technique is based on a generalized Fourier transform pair and it is implemented on a 486 DX2 machine. Unlike the conventional techniques, the proposed method is exact and does not rely on repeated analysis-based computer optimization that requires a large computer memory and speed. The proposed method requires less than a second to design a Chebyshev EH-plane transformer. The validity of the method has been shown by the design and analysis of several E-, H-, and EH-plane rectangular waveguide Ka-band transformers. The analysis subroutines were verified using published experimental results. © 1997 John Wiley & Sons, Inc. Int J Microwave Millimeter-Wave CAE 7 : 289–308, 1997.     

一枝蒿酮酸的制备、纯度检测及结构解析

从新疆一枝蒿中分离得到了一枝蒿酮酸,通过HPLC检测了其纯度(99.7%),色谱条件:VPODSC_(18)(150 mm×4.6mm,5μL)色谱柱,流动相为甲醇-0.5%磷酸溶液(V/V,45/55),检测波长245 nm。并采用IR,~1H NMR,~(13)C NMR,ESI-MS进行了表征。应用XRD单晶衍射确定了其晶体结构,该晶体属于单斜晶系,P2/m空间群,实验化学式为C_(30)H_(40)O_6(为双分子聚合体),实际化学式为C_(15)H_(20)O_3,晶胞参数:a=9.5295(7)nm,b=9.4821(6)nm,c=15.0469(10),α=90°,β=98.361(2)°,γ=90°,V=1345.18(16)nm~3,Z=2,M_r=496.62,D_c=1.226 g/cm~3,F(000)=536,R_1=0.0561,ωR_2=0.1265。接着采用量子化学中的密度泛函理论(DFT),在B3LYP/6-311G(d,p)基组下计算了该化合物的优化结构参数、电荷分布、分子总能量及前线轨道能量。算得的键长、键角数据和单晶衍射数据相符合。结果表明计算得到的分子几何优化结构可靠...     

Computer-aided system of supporting the processing the periodic signals, their analysis and visual control of results

In this paper, some questions of organizing a computer system oriented to supporting processes of processing and analysis of periodic signals are considered. It is supposed that a signal is recorded at the equidistant instants of time with an interval of digitization which is not dependent on the users will. In these conditions, a computer system should provide the following services: projecting an algorithm of data processing with supplying a needed program product; letting access to a certain set of procedures of analysis including the analysis of images and visual control of data before/after the processing. At the same time, the processing is understood as transformation of a signal for the purpose increasing its quality, and the analysis is understood as estimation of stipulated parameters and characteristics. It is offered to address to the certain window interface for the decision of questions which can arise here. In this paper, some results that were obtained in the course of development, designing and exploitation of such a computer system are given.     

祖师麻甲素的提取、高效液相色谱测定及量子化学研究

建立祖师麻的有效成分——祖师麻甲素提取和HPLC检测方法,并对其进行了量子化学研究。HPLC检测方法选用VP ODS C_(18)(250 mm×4.6 mm,5μm)色谱柱,流动相为甲醇-0.5%磷酸溶液(45:55),检测波长327 nm,量子化学计算在B3LYP/6-311G(2DF,PD)水平得到祖师麻甲素的几何构型、振动频率及能量,认识祖师麻甲素的分子内氢键结构。HPLC检测方法精密度、稳定性、重现性好,提取祖师麻甲素纯度为96.6%,量子化学计算结果与已知实验数据一致。     

Editorial board page for “EDPACS: The EDP Audit,Control, and Security Newsletter”, Volume 1, Number 13

Abstract

This is a scanned image of the original Editorial Board page(s) for this issue