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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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Nanoparticle Emissions from Metal-Assisted Chemical Etching of Silicon Nanowires for Lithium Ion Batteries
摘要： As one of the most promising anode materials for high-capacity lithium ion batteries (LIBs), silicon nanowires (SiNWs) have been studied extensively. The metal-assisted chemical etching (MACE) is a low-cost and scalable method for SiNWs synthesis. Nanoparticle emissions from the MACE process, however, are of grave concerns due to their hazardous effects on both occupational and public health. In this study, both airborne and aqueous nanoparticle emissions from the MACE process for SiNWs with three sizes of 90 nm, 120 nm, and 140 nm are experimentally investigated. The prepared SiNWs are used as anodes of LIB coin cells, and the experimental results reveal that the initial discharge and charge capacities of LIB electrodes are 3636 and 2721 mAh g-1 with 90 nm SiNWs, 3779 and 2712 mAh g-1 with 120 nm SiNWs, and 3611 and 2539 mAh g-1 with 140 nm SiNWs. It is found that, for 1 kW h of LIB electrodes, the MACE process for 140 nm SiNWs produces a high concentration of airborne nanoparticle emissions of 2.48 × 109 particles/cm3; the process for 120 nm SiNWs produces a high mass concentration of aqueous particle emissions, with a value of 9.95 × 105 mg/L. The findings in this study can provide experimental data of nanoparticle emissions from the MACE process for SiNWs for LIB applications, and can help the environmental impact assessment and life cycle assessment of the technology in the future.
关键词： Lithium ion batteries (LIBs),Metal-assisted chemical etching (MACE),Nanoparticle emissions,Silicon nanowires (SiNWs)
更新于2025-09-23 15:23:52
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The combination of Raman imaging and LIBS for quantification of original and degradation materials in Cultural Heritage
摘要： Quantification with nondestructive techniques is not very well developed in the field of Cultural Heritage despite its interest. In the last decades, several works have been published using Raman spectroscopy for quantifying. However, depending on the methodology used, the information provided by this technique is not complete, and the results could lead to misunderstanding when dealing with unknown samples. In this work, a novel double quantification using Raman imaging (its representativeness would be higher than point-by-point analysis) and Laser Induce Breakdown Spectroscopy (LIBS) analyses is presented for analysis of Cultural Heritage samples. Several dolomitic marble samples, with some calcite impurities, covered or not by a calcium oxalate (whewellite, CaC2O4·H2O) layer were analysed in order to optimize the novel methodology. The agreement between the quantitative results from the independent analyses of the Raman Image data and the LIBS data is consistent within the uncertainty arising from both techniques. Further, the same methodology was applied on the same samples but using point-by-point Raman analysis with portable instruments, and portable LIBS information, showing again a great agreement between them and with the results obtained using the laboratory instruments.
关键词： hydrated salts,quantification,Cultural Heritage,LIBS,Raman imaging
更新于2025-09-23 15:23:52
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Detection by LIBS of the deuterium retained in the FTU toroidal limiter
摘要： In this paper the Laser Induced Breakdown Spectroscopy (LIBS) measurement of the deuterium (used as a proxy for tritium) retained in and the surface elemental composition of the FTU Mo (TZM) toroidal limiter tiles, carried out from remote (～2.5 m) during short breaks of the operations or during machine maintenance, are reported. Single pulse technique has been used with the FTU vessel under high vacuum or in Nitrogen or Argon atmosphere. In vacuum experiments Dα and Hα lines have been detected with good resolution, while in Ar atmosphere (5 × 104 Pa) the two lines were partially overlapped due to Stark broadening. First results of measurements in N2 atmosphere (105 Pa) showed no presence of Dα and Hα lines. These measurements were also carried out for supporting the foreseen use of a robotic arm for an extended LIBS analysis of retained deuterium in the FTU vessel components.
关键词： Toroidal limiter,Deuterium retention,FTU tokamak,LIBS
更新于2025-09-23 15:22:29
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[IEEE 2018 37th Chinese Control Conference (CCC) - Wuhan (2018.7.25-2018.7.27)] 2018 37th Chinese Control Conference (CCC) - On-line Detection and Analysis of Alloy Steel Elements Based on the LIBS Technology and Random Forest Regression
摘要： The Laser Induced Breakdown Spectroscopy (LIBS) technology can be used to detect the elements in the alloy steel in real time. Quantitative analysis method of the traditional LIBS technology mainly has the calibration method and calibration free method, but there are two shortcomings: low prediction accuracy and over fitting. Random Forest Regression (RFR) algorithm can be used for classification and regression, can effectively avoid 'overfitting' phenomenon. Therefore, in this paper, we combine the random forest regression algorithm with laser induced breakdown spectroscopy applied to the detection of the concentration of alloy steel elements in the metallurgy industry. At the same time, compared with partial least squares method based on the LIBS, the results show that the random forest algorithm combined with the LIBS technology has the higher prediction accuracy, lower root mean square error and better robustness.
关键词： PLS,root mean square error,quantitative analysis,LIBS,RFR
更新于2025-09-23 15:22:29
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Analysis of alloy and solar cells with double-pulse calibration-free laser-induced breakdown spectroscopy
摘要： We applied variant of calibration free laser induced Breakdown Spectroscopy (CF-LIBS) approach for the compositional analysis of standard Gd/Ge/Si alloy and solar cells. The double pulse laser induced plasma was produced on the sample surface and the emission spectra were recorded at optimized interpulse delay and energy ratio. The Plasma temperature, determined using Boltzmann plot, was used to determine the concentration of all species present in a sample. The results are compared with reference values as well as conventional CF-LIBS results, which show that conventional and variant CF-LIBS results are similar and in close agreement to reference values. It is worth mention that the variant CF-LIBS results, but the approach is simpler and faster. Therefore, this approach was applied to three unknown polycrystalline silicon solar cells, which yield Al, C, Ca, Fe, In, Ti, Sb and Sn in the parts per million (ppm). This approach can potentially be applied for real-time trace monitoring in manufacturing processes of photovoltaic devices where conversion e?ciency depends strongly on impurities’ concentration.
关键词： Alloy and solar cells,Double pulse LIBS,Laser induced plasmas,Quantitative elemental analysis,Calibration free LIBS,Plasma parameters
更新于2025-09-23 15:21:01
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Multipulse laser ablation of BiSn eutectic: Noncongruent element transfer and morphology analysis
摘要： The surface of a eutectic BiSn target was ablated by several series of pulses at different spots using an excimer laser with a wavelength of 351 nm and a pulse duration of 20 ns. Morphology of ablation craters formed under a different number of pulses was analyzed with a scanning electron microscope, an optical profilometer, and an energy dispersion spectroscope (EDS). Laser-induced breakdown spectroscopy (LIBS) measurements were taken for each crater with the last pulse in the series of pulses. The ratio of peak intensities (Bi I peak at 472.25 nm and Sn I 563.16 nm) of LIBS spectra for craters formed by different series of pulses decreased from maximum at a single pulse to a stable magnitude after a series of 70 pulses. EDS mapping of crater areas for different series of pulses shows a decrease in Bi atoms abundance, in correlation with the decrease in normalized intensity of Bi peak LIBS spectra. The change of the chemical composition in the ablation area is explained based on the Knudsen evaporation model. For the first time, pronounced hydrodynamic effects resulting in the formation of 50 μm-high rims were observed. The unusual morphology of the ablated area is explained on the basis of hydrodynamic effects and recoil pressure.
关键词： LIBS,BiSn eutectic,laser ablation,EDS,SEM
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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Investigation into the Effect of Increasing Target Temperature and the Size of Cavity Confinements on Laser-Induced Plasmas
摘要： In this work, the effect of the sample temperature on the magnesium (Mg) and titanium (Ti) plasmas generated by a Q-switched Neodymium-doped Yttrium Aluminum Garnet (Nd:YAG) laser operating at its fundamental wavelength of 1064 nm has been investigated. We observed that increasing the sample temperature significantly enhanced the emission intensities of the plasmas. Comparing the emission peak intensities of the case of 100°C to the case of 300°C, we recorded a substantial enhancement of the peak intensities of the latter compared to the former. From these results it can be observed that increasing the sample temperature has a significant effect on the emission intensities of the plasmas. We also studied the plasma dynamics and found that increasing the sample temperature also decreases the air density around the Mg sample surface. The reduction in the air density resulted in a decrease in the radiation process and lowers collision probability. Furthermore, as the plasma expands, the plasma pressure also decreases. In addition, we also employed circular and square cavities to confine the titanium plasma, and investigated the effect of the sizes of the circular and square cavities on the titanium plasma. We observed a general improvement in the emission intensities with both the circular and square cavities and attributed this improvement to the plasma compression effect of the shock waves produced by the plasma within the cavities.
关键词： electron temperature,LIBS,Mg-alloy,electron density,cavity confinement,Ti-alloy
更新于2025-09-23 15:21:01
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Diagnosis of copper plasma by laser induced breakdown spectroscopy
摘要： In this paper influence of laser energy on the emission spectrum of laser copper-interaction and plasma parameter for plasma Copper by used a first harmonic generated wavelength of Nd:YAG exaction source. The metal plasma that had detection by HR4000 detection system (ocean optics) was use to different excited. plasma temperature via the Boltzmann plot diagram with measuring the electron density number by McWhirter CRITERION. Values of measuring (Ne), (Te) found between (61178776 K°) and (Ne) is (1.77*1015, 2.01*1015 cm-3) at 1064nm.
关键词： LIBS,Copper plasma,electron number density,self-absorption,plasma parameter
更新于2025-09-23 15:21:01