ISSN:0377-0486    

DOI:10.1002/jrs.1250250102

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper reviews some recent developments in Raman instrumentation. The introduction of the confocal design in most Raman spectrometers represents the latest advance in the field of instruments for Raman spectroscopy. It is the basis of new applications in the field of Raman microprobing and improvements in Raman imaging techniques. The basic principle of confocal microscopy is reviewed and its extension to Raman spectroscopy is discussed in terms of improved depth resolution which results in better background discrimination. A new concept of Raman imaging is also presented which benefits from the confocal system and overcomes most of the limitations of direct imaging techniques. A dual fibre‐optic remote analysis scheme is described which has been developed to optimize the collection of the scattered light while minimizing the interference from the optical fibre

ISSN:0377-0486    

DOI:10.1002/jrs.1250250103

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe first part of this review is devoted to medical applications of Raman spectroscopy as a diagnostic or analytical tool. Studies of human arteries, ocular lenses, living cells and chromosomes are reviewed, in addition to recent advantages in cancer diagnostics using Raman spectroscopy. The second and major part is devoted to a relatively new field, surface‐enhanced Raman scattering (SERS) spectroscopy of biomedical species. The SERS effect is accompanied by strong quenching of fluorescence and so enabes the range of species that can be investigated by Raman technique to be extended. The ultra‐high sensitivity of SERS enables spectra to be obtained at concentrations down to 10−10M. A wide range of experiments designed to probe the structure, topology and composition of biomedical species using SERS spectroscopy can be envisioned. Some of these currently being studied are: the determination of the distribution of drugs within a living cell and on the cellular membrane, the selective study of cell membrane components, the analysis of crude biomedical mixtures and extracts and new techniques, based on SERS spectroscopy, Fourier transform SERS spectroscopy and the SERS microprobe m

ISSN:0377-0486    

DOI:10.1002/jrs.1250250104

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractNon‐destructive examination of human brain tissues and several kinds of brain tumours using near‐infrared (1064 nm) excited Fourier transform (NIR‐FT) Raman spectroscopy is reported. The spectra from normal but edematous grey and white matter were similar to those of normal rat grey and white matter reported previously. The brain tumours investigated (glioma grade II and III, two acoustic neurinomas and central neurocytoma) gave Raman spectra essentially the same as to that of grey matter. Histological examination of glioma grade III revealed extracellular PAS‐positive materials, which have a band at 856 cm−1due to polysaccharides. One of the neurinoma contained a carotenoid which exhibited two resonance Raman peaks at 1157 and 1524 cm−1; another neurinoma did not contain the carotenoid. The appearance of a strong Raman peak at 960 cm−1suggested that the central neurocytoma of choroid plexus

ISSN:0377-0486    

DOI:10.1002/jrs.1250250105

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractIn a test experiment carried out in a small compact electroless plating facility, the concentrations of hypophosphite and phosphite in a nickel deposition bath of the Kanigen type were monitored on‐line with a dispersive Raman spectrometer. From the results, which agreed with off‐line Fourier transform (FT) IR data withinca. 10%, the molar amounts of nickel, hypophosphite and phosphite consumed and formed were calculated and compared with the stoichiometry of the nickel plating process adopted. In addition, nickel bath samples were also measured with an FT Raman spectrometer to compare the performances of both Raman techniques with a view to their application to aqueous soluti

ISSN:0377-0486    

DOI:10.1002/jrs.1250250106

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA range of thermally annealed isotropic and uniaxially drawn PEEK films were examined using polarized Fourier transform Raman spectroscopy in an attempt to obtain useful quantitative correlations with crystallinity. Both univariate (carbonyl stretching wavenumber measurement) and multivariate (partial least‐squares) calibrations were found to give good correlations, in the latter case yielding a standard error of prediction ofca.2.4% crystallinity. Both approaches show potential for measurement of crystallinity in both isotropic and oriented samples using just one correlation model. A previously suggested crystallinity index (the ratio of the 1600 and 1610 cm−1band intensities) failed to give a satisfactory correlation for either sample set. It was also shown that the ratio of the 1146 cm−1band intensities measured with the laser polarized perpendicular and parallel to the draw direction correlates with the sample birefrin

ISSN:0377-0486    

DOI:10.1002/jrs.1250250107

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractRaman microscopy has several advantages over other methods of analysis used to identify pigments from fine art objects. Examples are given of the use of this technique for the analysis of pigments taken from water‐colours, a lithograph and oil painting

ISSN:0377-0486    

DOI:10.1002/jrs.1250250108

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractIn situmeasurements were made of several organic chemical reactions in supercritical water using fiber‐optic probes, near‐infrared excitation and CCD array detection. The reactions studied include the conversion of cyclohexene to cyclohexane and benzene in the presence of a platinum catalyst, conversion of cyclohexanol to cyclohexene in the presence of a cobalt catalyst and the homopolymerization of styrene. Transition to the supercritical state was marked by a sudden decrease in the background and the appearance of intense Raman bands for dissolved organic compounds. The results indicate that this method of study is both sensitive and rapid enough to permit kinetic measurements, even when reactions are completed in less than 2

ISSN:0377-0486    

DOI:10.1002/jrs.1250250109

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA combined study based on scanning electron microscopy and Fourier transform Raman spectroscopy is presented for different kinds of diamond films. These films were obtained by the hot filament chemical vapor deposition (HFCVD) technique with both silica (SiO2) and silicon (Si) being used as substrates. CVD diamond films, having crystallite dimensions larger than about 1 μm (the wavelength for Raman excitation being 1.06 μm with an Nd:Yag CW laser), show tetrahedral chemical bonding and single‐crystal structural features being characterized by the appearance of the sharp first‐order 1330 cm−1Raman line characteristic of natural or high‐pressure synthetic diamonds. Films having crystalline dimensions<0.1 μm still exhibit tetrahedral (sp3) bonding. For such small crystals, the wavevector conservation rule for Raman spectroscopy of single crystals of diamond breaks down and only broad features, with the most intense Raman lines falling in the range 1260–1100 cm−1, are observed. This broad feature is characterized by some additional superimposed sharp lines, the maxima of which vary from sample to sample, showing the effect of overlap of spectra from various domain sizes of the crystallites, edge effects and contribution from other forms of non‐diamond carbon. The crystalline diamond peak observed at 1330 cm−1indicates that the diamond structure, at the temperature of synthesis, is retained in these films, and the large width of the Raman peak is probably due to the presence of defects. The main low‐wavenumber peaks observed in all spectra obtained with 1.06 μm excitation are interpreted as arising from the amorphous disordered sp3‐bonded carbons, which are formed as precursors to the crystalline diamond grown

ISSN:0377-0486    

DOI:10.1002/jrs.1250250110

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractFourier transform Raman (FTR) spectroscopy employing near‐IR laser radiation at 1.06 μm as the scattering source was used to obtain Raman spectra of some neat energetic materials and several propellant formulations containing those energetic materials. It is shown that only crystalline components of propellant formulations are easily detected by FTR spectroscopy. Also, FTR spectroscopy is shown to be a useful tool in determining the principle ingredient(s) in many non‐colored propellant formulat

ISSN:0377-0486    

DOI:10.1002/jrs.1250250111

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY