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Novel combined instrumentation for laser-induced breakdown spectroscopy and Raman spectroscopy for the <i>in situ</i> atomic and molecular analysis of minerals
摘要： An instrument combining laser-induced breakdown spectroscopy (LIBS) and Raman spectroscopy was developed for the in situ atomic and molecular composition analysis of minerals. The apparatus consists of an optical system, a sample chamber, a spectrometer for Raman and another for LIBS, as well as a control system equipped with laboratory-written software. Gypsum, calcite, prehnite, pearl, lazurite, and several mixtures of NaBr and CaCO3 were selected as samples for evaluation of the performance of the instrument. Sulfate, carbonate, silicate, and crystalline water were identified and different structures of CaCO3 were clearly distinguished by the use of a Gaussian fit. The limit of detection for CaCO3 in a NaBr mixture was 5.7 mg/g by Raman. LIBS was employed to determine calcium, magnesium, iron, sodium, aluminum, and carbon with the newly developed system. The limits of detection obtained for Ca, Na, and C were 90.2 lg/g, 84.6 lg/g, and 2.5 mg/g, respectively. The experimental results from commercial Raman spectroscopy instruments were used to verify and support the measurements from this novel instrument.
关键词： Instrumentation,Raman spectroscopy,laser-induced breakdown spectroscopy (LIBS),mineral,LIBRAS
更新于2025-11-25 10:30:42
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Rapid quality assessment of isogams using laser plasma spectroscopy
摘要： In this paper, the quality assessment of isogams is demonstrated by laser-induced breakdown spectroscopy (LIBS) using the comparative standardization method. Here, the mass concentrations of carbon and hydrogen, as basic elements of tar, relative to that of calcium, as an undesired element, are taken into account as principal parameters to determine the quality of isogams. Hence, the intensity ratios of H?? line of hydrogen (656.28?nm), the (0, 0) band of CN (388.34?nm), and the (0, 0) band of C2 (516.52?nm) to the line intensity of once-ionized calcium (317.93?nm) are considered as determinant markers for five different pre-known isogam brands. Qualitatively, classification of the isogams based on this approach is in full agreement with that obtained from the results of Fourier-transform infrared (FTIR) spectroscopy. In FTIR spectra, two stronger transitions of 2849?cm?1 and 2917?cm?1 related to the symmetric and asymmetric stretching vibrations of C–H play the principal role in the analysis of samples. Furthermore, the results obtained from energy-dispersive X-ray (EDX) analysis quantitatively confirm the LIBS outcomes. And finally, to reveal the differences between isogams from various aspects, the linear discriminant analysis (LDA) is exploited as a statistical approach.
关键词： FTIR spectroscopy,EDX analysis,Linear discriminant analysis (LDA),Laser-induced breakdown spectroscopy (LIBS),Isogams,Quality assessment
更新于2025-09-23 15:21:01
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Detection of Nutrition and Toxic Elements in Pakistani Pepper Powders Using Laser Induced Breakdown Spectroscopy
摘要： In the current paper, we applied laser induced breakdown spectroscopy (LIBS) to determine the elemental distribution of nutritional and trace heavy metals in pepper powders available in Pakistan using standard calibration curve laser induced breakdown spectroscopy (CC-LIBS) technique. The samples were found to contained elements like K, Ca, Mg, Na, Fe, Zn, Al, Pb, Cu, and Cr. Additionally, we also identified the atmospheric H-alpha line of hydrogen in the spectra which was used to estimate the electron number density. To achieve a highly sensitive LIBS system to determine nutritional and trace amounts of toxic metals in pepper powders and to achieve the best limit of detection, the LIBS system was optimized by studying the dependency of LIBS signal intensity on laser irradiance, variation in spacing between the focusing lens and target as well on the gate width. To justify the results of LIBS study, we also determined the concentration of alike (duplicate) peppers by digesting samples in appropriate solvents using a standard method like inductively coupled plasma-optical emission spectrometry (ICP-OES). The minimum detection limit was recognized for trace heavy metals from calibration curves. The results of LIBS displayed noteworthy conformity with those acquired from the ICP-OES analysis. Results of both the techniques clearly revealed that K was the most abundant element in all the peppers followed by Ca, Mg, Na, Fe, Al, Pb, Zn, Cu, and Cr. The relative accuracy of our LIBS system for different species as compared with ICP technique was in the range of 0.08–0.3 at 2.5 % error confidence. Conclusively, the present work demonstrated the suitability of LIBS technique due to its rapid, non destructive and eco-friendly approach for food security.
关键词： ICP-OES,detection of heavy metals,peppers analysis,laser induced breakdown spectroscopy,plasma parameters,Health impacts of toxic metals,laser applications
更新于2025-09-23 15:21:01
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Identification of Gravesa?? ophthalmology by laser-induced breakdown spectroscopy combined with machine learning method
摘要： Diagnosis of the Graves’ ophthalmology remains a significant challenge. We identified between Graves’ ophthalmology tissues and healthy controls by using laser-induced breakdown spectroscopy (LIBS) combined with machine learning method. In this work, the paraffin-embedded samples of the Graves’ ophthalmology were prepared for LIBS spectra acquisition. The metallic elements (Na, K, Al, Ca), non-metallic element (O) and molecular bands ((C-N), (C-O)) were selected for diagnosing Graves’ ophthalmology. The selected spectral lines were inputted into the supervised classification methods including linear discriminant analysis (LDA), support vector machine (SVM), k-nearest neighbor (kNN), and generalized regression neural network (GRNN), respectively. The results showed that the predicted accuracy rates of LDA, SVM, kNN, GRNN were 76.33%, 96.28%, 96.56%, and 96.33%, respectively. The sensitivity of four models were 75.89%, 93.78%, 96.78%, and 96.67%, respectively. The specificity of four models were 76.78%, 98.78%, 96.33%, and 96.00%, respectively. This demonstrated that LIBS assisted with a nonlinear model can be used to identify Graves’ ophthalmopathy with a higher rate of accuracy. The kNN had the best performance by comparing the three nonlinear models. Therefore, LIBS combined with machine learning method can be an effective way to discriminate Graves’ ophthalmology.
关键词： support vector machine (SVM),linear discriminant analysis (LDA),Graves’ ophthalmology,laser-induced breakdown spectroscopy (LIBS),k-nearest neighbor (kNN),generalized regression neural network (GRNN)
更新于2025-09-23 15:21:01
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Temporal and spatial evolution measurement of laser-induced breakdown spectroscopy on hydrogen retention in tantalum
摘要： Temporal and spatial evolution measurement of laser-induced breakdown spectroscopy on hydrogen retention in tantalum. Fuel retention measurement on plasma-facing components (PFCs) is an active field of study in magnetic confinement nuclear fusion devices. Laser-induced breakdown spectroscopy (LIBS) diagnostic method has been well demonstrated to detect the elemental distribution in PFCs. In this work, an upgraded co-axis LIBS system based on the linear fibers bundle collection system has been developed to measure the hydrogen (H) retention on tantalum (Ta) sample under the vacuum condition. The spatial resolution measurement on the different positions of the LIBS plasma can be achieved simultaneously with the various delay time. The temporal and spatial evolution of LIBS plasma and optimize the current collection system of the in situ LIBS in fusion devices.
关键词： tokamak,fuel retention,temporal and spatial evolution,laser-induced breakdown spectroscopy
更新于2025-09-23 15:21:01
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The classification of plants by laser-induced breakdown spectroscopy based on two chemometric methods
摘要： The applications of laser-induced breakdown spectroscopy (LIBS) on classifying complex natural organics are relatively limited and their accuracies still needs to be improved. To study the methods on classification of complex organics, three kinds of fresh leaves were measured by LIBS in this work. 100 spectra from 100 samples of each kind of leaves were measured and then they were divided into training set and test set in a ratio of 7:3. Two algorithms of chemometric methods including the partial least squares discriminant analysis (PLS-DA) and principal component analysis Mahalanobis distance (PCA-MD) were used to identify these leaves. By using 23 lines from 16 elements or molecules as input data, these two methods can both classify these three kinds of leaves successfully. The classification accuracies of training set are both up to 100% by PCA-MD and PLS-DA, respectively. The classification accuracies of test set are 93.3% by PCA-MD and 97.8% by PLS-DA, respectively. It means that PLS-DA is better than PCA-MD in classifying plant leaves. Because the components in PLS-DA process are more suitable for classification than those in PCA-MD process. We think that this work can provide a reference for plant traceability using LIBS.
关键词： classification of complex organics,partial least squares discriminant analysis,principal component analysis Mahalanobis distance,laser-induced breakdown spectroscopy
更新于2025-09-23 15:21:01
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EXPRESS: Potentialities of a Laser-Induced Breakdown Spectroscopy Technique in the Study of Polymer Composites
摘要： A laser-induced breakdown spectroscopy (LIBS) technique was used to evaluate the filler content in particulate epoxy–copper composites. A potential application for a direct and fast measurement of the filler in composites through the LIBS results is suggested using calibrated samples. The methodology used in this work makes possible the incorporation of LIBS as a quantitative technique for the study of particle metal filled epoxy composites, providing a method to obtain a direct estimation of the filler volume fraction.
关键词： LIBS,Laser-induced breakdown spectroscopy,epoxy composites,copper,plasma
更新于2025-09-23 15:21:01
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Potential Application of Lasera??Induced Breakdown Spectroscopy (LIBS) Data for the Determination of Cation Exchange Capacity (CEC) of Agricultural Soils
摘要： The potential for Laser Induced Breakdown Spectroscopy (LIBS) technique to predict cation exchange capacity (CEC) values in agricultural soils, based on a partial least square (PLS) regression model, was investigated by analysing soils (N = 225) using a portable LIBS system. The prediction from the validation set was 0.75 and the RMSE was 5.4 cmol + /kg. Analysis of the PLS loading weights showed that emission lines that correlate with the exchangeable cations (Ca, Mg, K and Na) and clay (Al and Si) are significant. Good quality predictions could be obtained from the model as described by the ratio of performance to deviation (RPD) values calculated for calibration (RPDc = 1.99) and validation (RPDv = 2.02). The ratio of performance to interquartile distance (RPIQ) for calibration (RPIQc = 3.20) and validation (RPIQv = 3.32) indicated excellent prediction capability. It has been demonstrated that LIBS spectra coupled with multivariate data analysis could be used to predict CEC of agricultural soils which is considered fast and a chemical-free technique.
关键词： cation exchange capacity,agricultural soil,analytical chemistry,spectroscopic method,laser induced-breakdown spectroscopy
更新于2025-09-23 15:21:01
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Spectral Characterization of Collinear Double-Pulse Laser Induced Breakdown Spectroscopy (DP-LIBS) for the Analysis of the Chinese Traditional Medicine <i>Artemisia annua</i>
摘要： A collinear dual-pulse laser induced breakdown spectroscopy (DP-LIBS) method was employed to analyze Chinese traditional medicine Artemisia annua. The spectral intensities and signal-to-background ratios of magnesium (II) 279.54 nm, CN 388.29 nm, calcium (II) 393.37 nm, and iron (II) 404.27 nm were used to evaluate the optical emission characteristics of A. annua induced by DP-LIBS. The temporal evolution characteristics, inter-pulse time, and laser energy values were optimized. In particular, the electron density and the temperatures of the plasma were reported as functions of the delay time. The results showed that the DP-LIBS had stronger intensity and better accuracy compared to single-pulse (SP) LIBS. The enhancement factors obtained using DP-LIBS for Mg, CN, Ca, and Fe were 7.2, 8.9, 13.8, and 3.4, respectively. This study provides important information about A. annua.
关键词： signal enhancement,plasma parameters,double-pulse laser induced breakdown spectroscopy (DP-LIBS),Artemisia annua
更新于2025-09-23 15:21:01
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Analysis of Salt Mixture Contamination on Insulators via Laser-Induced Breakdown Spectroscopy
摘要： The composition of contamination deposited on transmission line insulators can affect their surface flashover voltage. Currently, there is no rapid on-line method to detect this contamination composition in power grids. In this paper, we applied laser-induced breakdown spectroscopy (LIBS) to analyze contamination on insulator surfaces. Usually, Na and Ca salts are found in contamination along with various sulfate, carbonate, and chloride compounds. As an element’s detection method, LIBS can only measure a certain element content, for example, Ca. The mixture of various compounds with the same cations can influence the LIBS signal. The influence of mixing ratios on the calibration curves and relative spectral intensity was studied via LIBS. Na2CO3, NaHCO3, CaSO4, and CaCO3 samples containing different proportions of Na and Ca were prepared. The linear correlation coefficients (R2) for the Na and Ca calibration curves generated using various mixing ratios were analyzed. The results showed that the mixture ratio did not dramatically affect the linear calibration curves for mixtures containing the same cations. This finding may significantly reduce the difficulty of applying LIBS analysis for complex contamination on insulators. The laser energy density had effects on the spectral characteristics of the measured elements. The partial least-square regression (PLSR) model can improve the accuracy of Na and Ca prediction.
关键词： salt,insulators,calibration curves,laser-induced breakdown spectroscopy,contamination
更新于2025-09-23 15:21:01