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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
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Determination of uranium in ores using laser-induced breakdown spectroscopy combined with laser-induced fluorescence
摘要： The plasma emission spectrum of uranium in laser-induced breakdown spectroscopy (LIBS) is weak and susceptible to spectral interference, especially in a complex ore matrix. In this study, laser-induced breakdown spectroscopy combined with laser-induced fluorescence (LIBS-LIF) technology was proposed to enhance the spectral intensity of uranium in ores and eliminate spectral interference. Different combinations of excitation lines and analytical lines of the U element were investigated. In contrast with atomic lines, uranium ion lines are more suitable for determination of uranium. The relative number of U ions in plasma was studied for the best selection of excitation lines and analytical lines. The analytical performance of LIBS-LIF and LIBS for U determination in ores was compared. The results showed that all indicators had been significantly improved by LIBS-LIF. The slope, R2, LoD, RMSECV, ARE, and ARSD values of LIBS-LIF were 1.1 (cid:1) 105 counts per wt%, 0.998, 35 mg g(cid:3)1, 0.05 wt%, 6.69%, and 6.37%, respectively. This work demonstrates that LIBS-LIF has excellent potential in the exploration of uranium resources.
关键词： laser-induced breakdown spectroscopy,uranium,spectral interference,laser-induced fluorescence,ore matrix
更新于2025-09-23 15:19:57
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Optimization of Measuring Parameters for Two-dimensional Elemental Mapping in Laser-induced Breakdown Optical Emission Spectrometry Using 1-kHz Q-switched Nd:YAG Laser
摘要： This paper described how the lateral resolution of an elemental mapping was estimated in laser-induced breakdown optical emission spectrometry (LIBS), when the focus point of a high-frequency Q-switched Nd:YAG laser was moved on a sample surface, along with measuring the emission signal from the resultant plasma. Several measuring parameters were optimized to improve the lateral resolution; namely, they were an averaged laser power of 1 mJ/pulse, a laser repetition frequency of 1 kHz, a scanning rate of the laser beam of 0.5 mm/s, and an atmospheric gas pressure of He 1 000 Pa. Using these optimal parameters, a lateral resolution was obtained to be ca. 20 μm in the one-dimensional direction of laser scan. Furthermore, two model samples, in which regularly-aligned copper circles were deposited on a nickel plate, were irradiated by a scanning laser beam to determine actual resolving abilities both in a line direction along travelling the laser and in a two-dimensional direction over a certain sample area. The sample having an interval of 85 μm between the copper circles could give an emission image which was appropriately resolved in the two-dimensional as well as the one-dimensional direction; however, in the other sample having the 25-μm interval, the two-dimensional resolution became degraded compared to the resolution of the line scan, probably because the ablation grooves, which were left on the sample surface, had a width of more than 100 μm and were overlapped with each other in the observed area.
关键词： lateral resolution,copper,scanning laser beam,laser-induced breakdown plasma spectrometry,laser ablation
更新于2025-09-23 15:19:57
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Laser ablation at high repetition rate coupled to laser-induced breakdown spectroscopy for analysis of non-matrix matched standards
摘要： Laser ablation at kilohertz repetition rate coupled to laser-induced breakdown spectroscopy (kHz LA-LIBS) was used for the analysis of non-matrix matched metallic standards. Kilohertz LA-LIBS exploited the demonstrated advantages of the analytical technique referred to as laser-ablation laser-induced breakdown spectroscopy (LA-LIBS), while at the same time increased the amount of ablated mass available for analysis. By separating the laser ablation process from the excitation and analysis stages, every configuration of LA-LIBS has demonstrated to produce better analytical results during the analysis of non-matrix matched samples. This research reports the analytical response of five analytes (Al, Cu, Fe, Mg and Mn) from eight standard reference materials. The standards included four aluminum alloys, a high temperature alloy, a cupro-nickel alloy, a stainless steel and a low alloy steel. The analytical performance of kHz LA-LIBS was evaluated through the estimation of the signal-to-noise ratio, relative standard deviation, linearity and y-intercept of calibration curves and limits of detection. Calibration plots relating the analyte concentration to the Fe-normalized (internal standard), peak-to-background and net intensities were constructed. The increased amount of ablated mass in kHz-LA-LIBS rendered superior figures compared with traditional LIBS and other LA-LIBS configurations. The limits of detection of kHz LA-LIBS were improved by 3 to 14 times as compared to those reported previously and were estimated in the range of 0.07 and 0.30% by mass.
关键词： matrix effects,non-matrix matched standards,laser ablation laser-induced breakdown spectroscopy,high repetition laser ablation
更新于2025-09-23 15:19:57
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Collinear dual-pulse laser optical breakdown and energy deposition
摘要： A non-equilibrium model for laser-generated plasmas is used to represent collinear dual nano-second-pulse interactions. In the specific case considered, the breakdown is initiated with an ultraviolet (UV) laser pulse at 266 nm, which pre-ionizes the gas, and it is followed by a near-infrared (NIR) pulse at 1064 nm, which deposits significant energy into the ionized mixture. The model is validated against corresponding experiments, and simulation results are interrogated to understand key features of the plasma-kernel dynamics in the breakdown phase, and the initial post-breakdown vorticity and plasma-core decay.
关键词： energy deposition,laser-induced breakdown,non-equilibrium plasma,plasma dynamics,dual-pulse laser
更新于2025-09-23 15:19:57
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Coal Discrimination Analysis Using Tandem Laser-Induced Breakdown Spectroscopy and Laser Ablation Inductively Coupled Plasma Time-of-Flight Mass Spectrometry
摘要： The contribution and impact of combined laser ablation inductively coupled plasma time of flight mass spectrometry (LA-ICP-TOF-MS) and laser induced breakdown spectroscopy (LIBS) were evaluated for the discrimination analysis of different coal samples. This Tandem approach allows simultaneous determination of major and minor elements (C, H, Si, Ca, Al, Mg, etc), and trace elements (V, Ba, Pb, U, etc.) in the coal. The research focused on coal classification strategies based on principle component analysis (PCA) combined with K-means clustering, partial least squares discrimination analysis (PLS-DA), and support vector machine (SVM) for analytical performance. Correlation analyses performed from TOF mass and LIBS emission spectra from the coal samples showed that most major, minor, and trace elements emissions had negative correlation with the volatile content. Suitable variables for the classification models were determined from these data. The individual TOF data, LIBS data, and the combined data of TOF and LIBS, respectively, as the input for different models were analyzed and compared. In all cases, the results obtained with the combined TOF and LIBS data were found to be superior to those obtained with the individual TOF or LIBS data. The nonlinear SVM model combined with TOF and LIBS data provided the best coal classification performance, with a classification accuracy of up to 98%.
关键词： Principal component analysis,Support vector machine,Partial least squares discrimination analysis,Laser-induced breakdown spectroscopy,K-means clustering,Coal discrimination,Laser ablation inductively coupled plasma time of flight mass spectrometry
更新于2025-09-23 15:19:57
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Nanoparticle enhanced laser ablation and consequent effects on laser induced plasma optical emission
摘要： In this paper the plasmon enhanced ablation for elemental analysis is investigated with several experiments in order to point out the crucial questions concerning the laser matter interaction under the effect of plasmonic coupling between the nanoparticle (NP) system and the laser ablation pulse. The correlation between the electromagnetic field enhancement and the signal enhancement during NP enhanced laser induced breakdown spectroscopy (NELIBS), as well as the laser matter interaction at the nanoscale, is discussed in the case of noble metal NPs deposited on metal samples. The results suggest that, while laser pulse energy is concentrated in the space between the NPs, the NP system is shielded by the field enhancement distribution after the laser pulse interacts with the plasmons of the NP system. Finally the comparison of the laser energy transfer to the sample between NELIBS and conventional LIBS is discussed.
关键词： LIBS,Nanoparticle enhanced laser induced breakdown spectroscopy (NELIBS),laser ablation,plasmonic enhanced ablation,LA-ICP-MS
更新于2025-09-23 15:19:57
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Evaluation of stress on metal surfaces by laser-induced breakdown spectroscopy
摘要： In this study, we evaluated the feasibility of using laser-induced breakdown spectroscopy (LIBS) to determine the stress generated in metal materials by comparing measured stress levels with those determined by x-ray diffraction (XRD). Magnesium (Mg) alloy specimens underwent impact stress generated under ultrasonic peening. Stainless steel specimens were subjected to bending stress. The reference stress for each specimen was measured using XRD. LIBS measurements were performed to determine the correlation between stress distribution and the ratio of ionic to atomic spectral line intensity. The stress distribution from the surface to the interior of the ultrasonic-peened specimens measured by LIBS showed a similar tendency to that measured by XRD, but there was a difference in the maximum measurable depth. Additionally, the tensile and compressive stress distributions measured by LIBS on bending specimens showed similar trends to those of XRD. From these results, it was possible to measure the correlation between the stress state of the metal matrix and the spectral line strength of LIBS, thus confirming the potential for stress measurement using LIBS.
关键词： laser-induced breakdown spectroscopy,mechanical stress,spectral line
更新于2025-09-23 15:19:57
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Spectral analysis of Miracle Moringa tree leaves using X-ray photoelectron, laser induced breakdown and inductively coupled plasma -optical emission spectroscopic techniques
摘要： The antioxidant Moringa oleifera (a medicinal plant) leaves (MOLs) containing diverse nutrients are highly beneficial for the human health. The MOLs upon consumption can lower the blood sugar, cure the heart diseases, and reduce the inflammation. In this perception, the “primary nutrients contents” in the dry MOLs (pellet samples) were evaluated for the first time using the XPS, LIBS and ICP-OES techniques. The XPS analysis of the MOLs showed the presence of vital elements like calcium (Ca), magnesium (Mg), manganese (Mn), copper (Cu), phosphorous (P), sulfur (S) and zinc (Zn). The LIBS analyses of the MOLs revealed the atomic and ionic spectral lines corresponding to the essential nutrients such as the Ca, Na, K, Fe, Mg, Mn, Cu, P, S and Zn. The calibration free LIBS algorithm (CF-LIBSA) was developed to quantify the content of each element in the dry MOLs. In addition, the LIBS results were validated by the analysis using ICP-OES standard analytical technique. The elemental contents in the MOLs obtained from the CF-LIBS analyses were counter verified by the ICP-OES results. Present results are highly valuable for the development of a traditional herbal medicine using the miracle MOLs.
关键词： Calibration free LIBS algorithm,Laser induced breakdown spectroscopy,Moringa oleifera leaves,X-ray photoelectron spectroscopy,Inductively coupled plasma atomic emission spectroscopy
更新于2025-09-23 15:19:57
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Rapid qualitative evaluation of velvet antler using laser-induced breakdown spectroscopy (LIBS)
摘要： The aim of this work is to study a rapid analysis method to evaluate velvet antler products qualitatively, using laser-induced breakdown spectroscopy (LIBS). We used principal component analysis to select feature lines of LIBS spectra of velvet antler, and built two partial least squares-discriminant analysis (PLS-DA) classification models to distinguish between inferior and good quality velvet antler by using the intensities of all lines and feature lines as input variables, respectively. The correct classification rates (CCRs) of these two models were both 100%. In order to test the robustness of the models, we used these two models to discriminate the samples not included in the training set to build the model, and the CCRs were 87.5% and 100%, respectively. The results demonstrated that combining LIBS with PLS-DA could evaluate the quality of velvet antler, and the robustness could be improved by using the intensities of feature lines as inputs.
关键词： qualitative evaluation,partial least squares-discriminant analysis (PLS-DA),velvet antler,principal component analysis (PCA),laser-induced breakdown spectroscopy (LIBS)
更新于2025-09-23 15:19:57