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1.
灰色分析体系选择测定研究:I.理论基础和模拟研究   总被引:2,自引:0,他引:2  
首先运用分析物响应光谱K-系数对含基体和化学干扰的混合光谱进行分离,求得基体与化学干扰总光谱;进而运用H点标准加入法,结合基与化学干扰总光谱K-系数,实现对分析的选择测定,最后通过数据模拟研究了零波长(λ0)和H点波长(λH)的选择方法。  相似文献   

2.
一个基于诊断的稳健主成分分析方法   总被引:1,自引:0,他引:1  
经典的主成分分析方法易受异常点影响。本文根据该方法的特点,提出一新的诊断方法,将多变量数据中异常剔除后再进行主成分分析,构成有效的稳健主成分分析法。用此法处理二组实际数据,结果令人满意。  相似文献   

3.
王乃岩  许国旺 《分析化学》1995,23(11):1329-1332
本文介绍了大气毒物傅里叶变换红外光谱自动差减定量软件,介绍了方法的原理和软件的结构与功能。该技术能够进行数据库的实时咨询,差减谱位的智能搜索和光谱自动差减定量,实现了大气毒物自动定量分析。运用于实际样品分析,快速准确,优于其它的傅里叶变换红外光谱定量技术。  相似文献   

4.
近红外光谱技术结合主成分分析法用于子宫内膜癌的诊断   总被引:3,自引:0,他引:3  
应用近红外光谱技术结合化学计量学方法研究了子宫内膜癌组织近红外光谱特征提取和早期诊断的可行性. 测定了154 例子宫内膜组织切片的近红外光谱, 选取适宜的波段和光谱预处理方法进行主成分分析, 很好地区分了癌变、增生和正常子宫内膜组织切片, 并且分辨出处于不同分化期的组织切片, 为子宫内膜癌的早期诊断提供了可靠依据. 该法快速、简便, 有望发展成为一种新型的肿瘤无创诊断方法.  相似文献   

5.
以柚子皮为原料,采用一步水热合成法制备了稳定性好、量子产率高的水溶性氮掺杂碳点(N-CDs)。利用透射电子显微镜、傅立叶变换红外光谱、X射线光电子能谱对其形貌和结构进行了表征,并通过紫外吸收光谱和荧光光谱对其光物理性质进行了详细研究。实验结果表明,该N-CDs传感平台对槲皮素呈现出高灵敏、高选择性猝灭型响应,检出限为60 nM。同时,通过荧光寿命的测定,发现该猝灭机理为静态猝灭。此外,该方法可用于实际样品血清和尿液中槲皮素的检测,表现出良好的准确性和重现性,表明具有实际应用价值。  相似文献   

6.
最小一乘稳健多元分析校正   总被引:1,自引:3,他引:1  
王继红  谢玉珑 《分析化学》1994,22(3):255-260
本文论述最小一乘求解的多元分析校正算法,探讨了最小一乘较常规最小二乘法及其他隐健算法的优点。用计算机数值模拟及实际多组分光谱体系对方法进行了检验,展示了最小一乘法在分析化学计量学中实际应用的可行性。  相似文献   

7.
人工神经网络用于近红外光谱预测汽油辛烷值   总被引:5,自引:0,他引:5  
本文对BP人工神经网络(ANN)方法在汽油的辛烷值与其近红外光谱光谱吸光度的关系之间进行关联预报方面进行了研究。采用35个汽油实际样本数据,建立了利用汽油的近红外光谱光谱吸光度预测汽油辛烷值的BP人工神经网络模型。对所有辛烷值的计算结果与实测值进行了比较,得到的预测值与实测值计算误差小于1.55%。  相似文献   

8.
以天然产物野酸枣和色氨酸为原料,通过水热法一步合成量子产率为16.9%的氮掺杂荧光碳量子点。该碳量子点具有良好的水溶性和耐光性,在高盐环境中也呈现出了较高的稳定性。应用荧光光谱、透射电子显微镜(TEM)、傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)对碳量子点进行了表征。此外,Hg^2+能够有效地猝灭碳量子点的荧光,猝灭机理为电子转移的动态猝灭。基于此,可将碳量子点作为荧光探针检测Hg^2+。方法对Hg^2+的检测范围为1~50 nmol/L,检出限为0.26 nmol/L,能够应用于实际水样中Hg2+含量的测定。  相似文献   

9.
高分辨阿达玛变换显微光谱成像系统研究   总被引:2,自引:0,他引:2  
阿达玛变换(HT)是一种多通道的光谱调制技术,基于这一原理,研制了一种显微光谱成像系统.通过光学设计,除可以获得微小试样(如单个细胞)的光谱以外,还可以对试样进行分光谱成像,得到分辨率为256×256像素的256级灰度图像.通过对两种不同荧光发射波长的CdSe/ZnS量子点进行的分光谱成像测试表明,本系统具有良好的分光谱成像能力,可以对具有复杂光谱的物质针对其某一特定成分进行成像.  相似文献   

10.
通过对各种近红外光谱分析仪进行系统的测试和论证,初步建立了一套近红外光谱分析仪的校准方法.该方法各项指标评价结果符合仪器的设计性能及实际测试工作要求.  相似文献   

11.
Simulation of atomic emission and absorption spectra has been carried out in order to improve and to check the validity of measurement techniques and data processing for plasma diagnostic. Doppler, Van der Waals, Stark and instrumental broadenings and shifts have been taken into account. The effect of self-absorption has also been considered. The input parameters are pressure, temperature, electron density, and emitting species number density. In such calculations data needed for the determination of collisional and Stark broadenings are not always available. An empirical method of data evaluation is described and discussed. The limits and the precision of this modelling are discussed with experimental examples. This simulation method has been applied to the diagnostic of volatilisation phenomena in thermal plasma spraying processes. It has been used to assist in the choice of diagnostic lines, instrumental parameters and data processing parameters. It has also been used to evaluate the accuracy of the temperature and density distributions calculated from spectroscopic measurements.  相似文献   

12.
从铅中毒发铅诊断标准、发铅诊断试验及发铅诊断临床应用3个方面论述了发铅检测法在铅中毒诊断、筛查和监督中的实际应用问题。根据临床经验和发铅-血铅比值确定了居民发铅正常值上限及铅中毒发铅诊断分级标准;即使以血铅测定值为"金标准",诊断试验表明,发铅测定在铅中毒诊断中仍有实际应用价值;发铅检测法自上世纪60年代以来一直沿用至今,绝大多数研究者认为,发铅测定是诊断、筛查铅中毒和监督环境铅污染最简单、有效的工具。  相似文献   

13.
This work presents the validation study of the comprehensive two-dimensional gas chromatography (GC×GC)–time-of-flight mass spectrometry method performance in the analysis of the key World Anti-Doping Agency (WADA) anabolic agents in doping control. The relative abundance ratio, retention time, identification and other method performance criteria have been tested in the GC×GC format to confirm that they comply with those set by WADA. Furthermore, tens of other components were identified with an average similarity of >920 (on the 0–999 scale), including 10 other endogenous sterols, and full mass spectra of 5,000+ compounds were retained. The testosterone/epitestosterone ratio was obtained from the same run. A new dimension in doping analysis has been implemented by addressing separation improvement. Instead of increasing the method sensitivity, which is accompanied by making the detector increasingly “blind” to the matrix (as represented by selected ion monitoring mode, high-resolution mass spectrometry (MS) and tandem MS), the method capabilities have been improved by adding a new “separation” dimension while retaining full mass spectral scan information. Apart from the requirement for the mass spectral domain that a minimum of three diagnostic ions with relative abundance of 5% or higher in the MS spectra, all other WADA criteria are satisfied by GC×GC operation. The minimum of three diagnostic ions arises from the need to add some degree of specificity to the acquired mass spectrometry data; however, under the proposed full MS scan method, the high MS similarity to the reference compounds offers more than the required three diagnostic ions for an unambiguous identification. This should be viewed as an extension of the present criteria to a full-scan MS method.  相似文献   

14.
A method for the determination of steroid hormones by reversed-phase HPLC has been applied to the analysis of biological fluids from healthy individuals and patients with endocrine systems diseases. The obtained chromatographic profiles were processed by the method of principal component analysis and method of soft independent modeling of class analogy. The principle possibility of using the results of chemometric processing of the chromatographic profiles as an additional diagnostic criterion for the treatment of some endocrine pathologies has been shown.  相似文献   

15.
A Gaussian elimination form of inverse iteration within the complex coordinate approach is shown to produce a simple uniform method of finding both real bound state energies and complex resonant state energies for several problems, which have been treated by a variety of methods in the literature. The energy shift method for expectation values is shown to be a useful diagnostic tool.  相似文献   

16.
A novel procedure for making the pH responsiveness of a Gd-based probe independent of its concentration has been developed. The method is based on a ratiometric approach and requires the measurement, at magnetic fields higher than 1 T, of the paramagnetic contribution to the longitudinal and the transverse NMR relaxation rates of water protons in the presence of a Gd-based probe with a rotational mobility in the nanosecond time scale. The method has been tested and validated in vitro by using a macromolecular adduct based on the polyornithine backbone, whose rotational mobility is pH dependent. The results reported in this communication improve substantially the diagnostic potential of MRI responsive agents.  相似文献   

17.
临床诊断试剂及其诊断方法研究进展   总被引:2,自引:0,他引:2  
本文结合作者工作,综述了现代临床化学所用诊断试剂,以及诊断方法学研究的某些进展与发展趋向。  相似文献   

18.
Polarography is still the best known classical measuring method in electroanalytical chemistry. However, in recent years its position has been challenged by cyclic voltammetry (CV). Simple diagnostic criteria and relatively easily acquired measuring techniques have hastened this development. Cyclic voltammetry has the further attraction of providing information not only on the thermodynamics of redox processes but also on the kinetics of heterogeneous electron-transfer reactions and coupled chemical reactions. The characteristic shapes of the voltammetric waves and their unequivocal position on the potential scale virtually fingerprint the individual electrochemical properties of redox systems. For this reason the method has been labeled “electrochemical spectroscopy”.  相似文献   

19.
The mass spectra of a series of indolosteranes have been obtained in order to investigate whether or not such a method may prove a diagnostic tool in determining structure. While differences are revealed they are sometimes too slight for this purpose. An interesting observation made here is that in the fragmentation pattern those ions which contain the indole grouping usually predominate.  相似文献   

20.
Electron energy distributions have been determined from thin-target Bremsstrahlung for many years. For thick-target Bremsstrahlung however, even the simple diagnostic that immediately gives the distribution from the second derivative of the emissivity has been established only recently. For cases when the underlying assumptions are unjustified, further deconvolutions are proposed: a matrix inversion method involving a functions basis, and an iterative method which is more general and stable. Both methods could also be applied to thin-target Bremsstrahlung.  相似文献   

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