seashell analysis; LIBS; graphite enriched process; Sr/Ca; shell growth;RAMAN-SPECTROSCOPY; CLASSIFICATION; PROFILES; RATIOS; GROWTH; SHELLS

Seashell has been applied as an indicator for ocean research and element analysis of the seashell is used to track biological or environmental evolution. In this work, laser-induced breakdown spectroscopy (LIBS) was applied for elementary analysis of an ezo scallop-shell, and a graphite enrichment method was used as the assistance. It was found that LIBS signal intensity of Ca fluctuated less than 5%, in spite of the sampling positions, and Sr/Ca was related to the shell growth. A similar variation was also found when using a direct LIBS analysis on the shell surface, and it might be more practicable to track shell growth by investigating Sr/Ca ratio with Sr ionic line at 421.6 nm. The obtained results prove that calcium (Ca) is qualified as an internal reference for shell analysis, and LIBS is a potential analytical method for seashell study.

Stimulated Raman; Laser-induced breakdown; Pulses laser; The fluorescence lifetime;STIMULATED RAMAN-SCATTERING; MATERIAL REMOVAL; ENHANCEMENT; EMISSION; SINGLE

To study the time evolution characteristics of plasma fluorescence, aluminum feature spectrum was measured and analyzed through dual-pulse laser-inducedbreakdown spectroscopy in the standard ambient temperature and pressure experimental conditions. Two Nd:YAG lasers were used to perform the experiment; one laser ablated the target, and the other reheated the plasma in air. The plasma emission intensity was enhanced at an optimal inter-pulse delay time of 200 ns. The plasma fluorescence lifetime was measured in a dual-pulse laser excitation mode at different inter-pulse delays. The plasma fluorescence lifetime changed with the changing of inter-pulse delay under double pulse excitation. The results can further understand of the time evolution of the plasma under double-pulse laser excitation. (C) 2017 Elsevier GmbH. All rights reserved.

Laser-induced breakdown spectroscopy; Vector space model; Geological cutting; Identification;SAMPLES

Vector Space Model (VSM) was originally used in document retrieval. It is characterized by extracting the texts from the document and converting the document into a text vector space. VSM compares the similarity between document text vectors and text retrieval text vectors. The document retrieval is accomplished according to the similarity based on the nearest template principle of template matching in pattern recognition. This article applied such principle into the identification of samples based on the characteristic of LIES spectrum. To create the database of characteristic peaks of training dataset, we obtained the spectra template of all kinds of samples from the training dataset and extracted the wavelength and intensity of peaks from the spectra template. In another hand, to create the database of characteristic peak vectors for all the training samples, we calculated the spectral characteristic peak weight and converted the spectra to peak vector space. The characteristic peak vector of the test data set was obtained by the same way. The cosine value between the characteristic peak vector of test data and every characteristic peak vector in the database were calculated and the maximum cosine was taken as the identification result. Geological cuttings, the research subject, were identified by the VSM in this paper. The result demonstrated that the VSM could rapidly identify the spectra from 4 kinds of geological cuttings' LIES spectral and the correct identification rate was 100% after the spectra of the test dataset were averaged. The proposed LIES spectral identification method based on VSM can be expanded to the identification of other spectral data.

SURFACTANT SENSORS; AQUEOUS-SOLUTIONS; SYSTEM; LIBS

Domestic detergents are widely used and the detection of detergent residues on tableware is closely related to people's health. As is known to all, it is difficult to sample and measure the residual detergent on tableware. The purpose of this paper is to explore a rapid in situ detergent residues detection method. We have using laser-induced breakdown spectroscopy (LIBS) measured the detergent on porcelain plate. Based on our previous research, we further studied the spectra of detergent in argon atmosphere, and compared them with that in air. We found the spectral characteristics of the cyanogroup (CN) were related to the air around the measuring point. It was indicated that CN could not as previously speculated be used as the LIBS detection feature of detergent. The improvement of signal-to-noise ratio (SNR) in argon environment was proved and we made a study of semi quantitative measurement by the peak height of 330.30 nm in argon atmosphere. An experiment measuring the detergent on tableware after washed was taken. It illustrated that the LIBS technology has promising potential applications for tableware cleaning process or food production process as a means of on-line detection.