Raman spectrum is the fingerprint of the molecule, and Raman peak locations relate to the structure of the molecule, so
identification of specimen can be performed based on Raman spectroscopy. However, classification of Raman peaks of
the mixture is usually difficult, especially, when Raman peaks of one component are overlapped with, even dominated
by those of other component. As a nonlinear dynamic system, artificial neural network simulates the functions and
characters of biological neural systems, and has been widely used in signal process. Firstly, this paper introduced the
principles of Raman spectroscopy and the technique of artificial neural network. Secondly, Raman spectra of the
mixtures of CCl4 and ClO4
- were analyzed using BP artificial neural networks. The results showed that artificial neural
network technology is flexible, affordable and easily adapted to qualitative analysis of Raman spectrum of the mixture.
Raman spectroscopy combines the fingerprinting advantage of mid-JR spectroscopy with the ease of use and remote,
non-invasive capability of near-JR spectroscopy. Now, Raman spectroscopy is fast becoming a perfect technique of
analysis in raw material identification, verification, process control in biological, chemical and industrial fields, because
Raman spectra are a fingerprint for the molecular species present in a specimen and can be used for both qualitative
identification and quantitative determination. This paper introduces that low-resolution Raman spectroscopy (LRRS)
satisfies the need for a highly useful, low-cost spectroscopic approach to both qualitative and quantitative analyses. First
the principles and methods of analyses were introduced, especially quantitative analyses based on ratio method, and then
several applications were described, which were representatives of qualitative and quantitative analyses. Secondly, these
experimental results were discussed and analyzed in detail. The results show that the Raman spectroscopy technology is
flexible, affordable and easily adapted to on-site and in situ analysis.
The characterization of species in aqueous solutions has presented a challenge to analytical and physical chemist,
because the JR absorption of the aqueous solvent is so intense that it becomes difficult to observe the solute in the water
by JR absorption. In contrast, Raman spectrum of the solute is unaffected by the water, so the weak scattering of water
makes the technique well suited to aqueous samples, and the Raman spectrum exhibits well-defined bands corresponding
to fundamental modes of vibration. In addition, Raman spectroscopy has some inherent advantages in aqueous solution
analysis, because the spectral features of signals from different species are much more distinct, and it provides
characteristic signatures for samples, such as blood, protein and cholesterol. All the advantages make Raman
spectroscopy be a potential alternative for the study of aqueous solutions. Now, Raman spectroscopy has been applied to
studying samples in aqueous solutions, blood serum, intracellular protein levels. Now, industrial wasted water contains
many organic contaminants, and it is necessary to determine and monitor these contaminants. The paper first introduces
Raman spectroscopy, and then describes its applications to determining the components in aqueous solutions, analyzes
and assignes the Raman spectra of o-dichlorobenzene, o-xylene, m-xyiene and p-xylene in detail. The experimental
results demonstrate that Raman spectroscopy is a particularly powerful technique for aqueous solutions analyses.
By means of Artificial Neural Network and Back-Propagation algorithm, the multi-component of azo-dyes can be
qualitatively and quantitatively analyzed simultaneously, though their Raman spectra are overlapped. This article
designed a Back-Propagation algorithm network to analyze the multi-component of azo-dyes (Sudan I and Sudan III). In
conclusion, by using the Artificial Neural Network and Raman spectrum can be a good choice for resolving
Being an industrial dye, the Sudan I may have a toxic effect after oral intake on the body, and has recently been shown to cause cancer in rats, mice and rabbits. Because China and some other countries have detected the Sudan I in samples of the hot chilli powder and the chilli products, it is necessary to study the characteristics of this dye. As one kind of molecule scattering spectroscopy, Raman spectroscopy is characterized by the frequency excursion caused by interactions of molecules and photons. The frequency excursion reflects the margin between certain two vibrational or rotational energy states, and shows the information of the molecule. Because Raman spectroscopy can provides quick, easy, reproducible, and non-destructive analysis, both qualitative and quantitative, with no sample preparation required, Raman spectroscopy has been a particularly promising technique for analyzing the characteristics and structures of molecules, especially organic ones. Now, it has a broad application in biological, chemical, environmental and industrial applications. This paper firstly introduces Sudan I dye and the Raman spectroscopy technology, and then describes its application to the Sudan I. Secondly, the fingerprint spectra of the Sudan I are respectively assigned and analyzed in detail. Finally, the conclusion that the Raman spectroscopy technology is a powerful tool to determine the Sudan I is drawn.
Laser-induced ultrasonic technology has been extensively studied and widely applied recently, for its advantages such as noncontract operation, nondestructive testing, broad bandwidth, high time, and space resolution, no shape limits on samples, etc. Firstly, the principles of laser ultrasonic generation and detection were introduced. Secondly, the application of the ultrasonic ratio method in measuring the surface defects was presented in detail. The experimental results were analyzed. Because the ratio method avoids measuring the velocity of the surface wave and reduces the experimental error, it is much more practical, reliable and effective in surface defect measurements.
Raman Spectroscopy is a molecular vibrational spectroscopic technique based on the Raman effect, which is characterized by the frequency shift that caused by interactions of molecule and photon and shows the information in molecules. There are many advantages to study the sample with Raman spectroscopy, such as simple system structure with relative lower cost, wide variety of detectable masses, nondestructive detect for multicomponent sample, good sensitivity, feasibility of real-time analysis and online examination assisted with optical fiber and computers, etc. As a powerful tool for quantitative or qualitative analysis, Raman spectroscopy has been employed to solve certain unique problems in chemical and environmental analysis and in industrial process monitoring and control. Now, there are many kinds of organic contaminants, particularly aromatic molecules, in industrial waste water, so it is essential to determine and monitor these contaminants. This paper analyzed the Raman spectra of benzene and benzene derivatives (toluene, ethylbenzene, chlorobenzene, and nitrobenzene) in detail, and assigned their Raman identified spectra. The results show that Raman spectroscopy is useful to analyze benzene derivatives in waste water.
As a new branch of ultrasonics, laser-induced ultrasonics is developed quickly, and has wide applications in many areas recently, for its advantages such as non-contract operation, non-destructive testing, broad bandwidth, high time resolution, high space resolution, no shape limits on samples, etc. Firstly, the principles of the laser-induced ultrasonic generation, e.g., the thermoelastic excitation theory and the ablation excitation theory, were introduced. This paper also described the laser-induced ultrasonic detection by means of the confocal Fabry-Perot interferometer (CFPI). And then its applications in non-destructive testing in solids were introduced in detail. Based on the principles of the laser-induced ultrasonic generation and detection, the structure of the laser ultrasonic detection system was presented. From the velocities of compress wave and surface wave measured by the detection system, elastic constants of aluminium were worked out. The experimental results were in good accordance with the theoretical predictions, which demonstrated that laser ultrasonic technique is practical, reliable and effective. Future prospects for such technology were pointed out finally.