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Detail investigation of toxicity, bioaccumulation, and translocation of Cd-based quantum dots and Cd salt in white mustard
摘要： In this study, a model crop plant white mustard (Sinapis alba L.) was treated with an aqueous dispersion of silica-coated CdTe quantum dots (CdTe/SiO2 QDs) in a 72-hours short-term toxicity test. The toxicity was established via measurements of (i) the root length and (ii) the chlorophyll fluorescence. These results were compared to two other sources of cadmium, free Cd ions (CdCl2) and prime un-shell nanoparticles CdTe QDs. Tested compounds were applied in concentrations representing 20 and 200 μM Cd. The uptake and translocation of Cd were investigated using inductively coupled plasma optical emission spectrometry (ICP-OES) and the spatial Cd distribution was investigated in detail applying laser induced breakdown spectroscopy (LIBS). The LIBS maps with a lateral resolution of 100 μm were constructed for the whole plants, and maps with a lateral resolution of 25 μm (micro-LIBS arrangement) were used to analyse only the most interesting parts of plants with Cd presence (e.g. root tips or a part crossing the root into the above-ground part). Our results show that the bioaccumulation patterns and spatial distribution of Cd in CdTe/SiO2 QDs-treated plants differ from the plants of positive control and CdTe QDs. Fluorescence microscopy photographs revealed that CdTe/SiO2 became adsorbed onto the plant surface in comparison to CdTe QDs. Further, a physico-chemical characterization of QDs before and after the test exposure showed only minor changes in the nanoparticle diameters and no tendencies of QDs for agglomeration or aggregation during the exposure.
关键词： nanoparticles,cadmium,laser-induced breakdown spectroscopy,Sinapis alba L.,uptake,translocation
更新于2025-09-23 15:19:57
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Spatial confinement effect on CN emission from nanosecond laser-induced PMMA plasma in air
摘要： In this paper, a PMMA target was ablated to study spatial confinement effect on CN emission of laser-induced PMMA plasma in air. Four cylindrical cavities with same depth and different diameters (4, 6, 8, and 10 mm) were used to confine the nanosecond laser-ablated PMMA plasma plume. Laser pulse energies were 40, 50, and 60 mJ. The influence of cavity diameter on emission band and vibration temperature of CN molecule was demonstrated, the results showed an obvious increase in the emission and vibration temperature of CN molecule by using the cylindrical cavity. When the cavity diameter was smaller at a fixed laser energy, the emission enhancement of CN molecule appeared earlier, and the CN molecule had stronger emission and vibration temperature. For a fixed diameter cavity, when the laser energy was higher, the CN molecule presented stronger emission and higher vibration temperature, and the emission enhancement also appeared earlier. The enhanced effect on the spatial confinement mainly comes from shock wave produced by the laser-induced PMMA plasma. The spatial confinement cavity can reflect the shock wave, and the shock wave compresses the plasma plume, resulting in an improvement in the temperature and density of the plasma. Therefore, the optical emission of CN molecule increases as the shock wave interacts with the PMMA plasma.
关键词： CN,PMMA,laser-induced breakdown spectroscopy,spatial confinement
更新于2025-09-23 15:19:57
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Multivariate analysis and laser-induced breakdown spectroscopy (LIBS): a new approach for the spatially resolved classification of modern art materials
摘要： The ever-increasing speed of exchange of ideas, information, and culture allows contemporary art to be in constant growth, especially concerning the choice of artistic materials. Their characterization is not only crucial for the study of artistic techniques but also for research into the stability of the material and, consequently, the best preservation practices. For this aim, an analytical method should have the advantages of not requiring sample preparation, performing superficial micro-analysis, and obtaining detailed spectral information. For this study, laser-induced breakdown spectroscopy (LIBS) was employed. It was used for the identification of modern paints composed of inorganic pigments and organic binders, such as acrylics, alkyds, and styrene-acrylics. Principal component analysis (PCA) was used to classify the different pure materials, above all, the polymeric binders. To distinguish the paint mixtures, whose LIBS spectral results were more complex due to the pigment/binder interaction, a statistical method recently employed in the cultural heritage field was chosen, namely, random decision forest (RDF). This methodology allows a reduction of the variance of the data, testing of different training data sets by cross-validation, an increase of the predictive power. Furthermore, for the first time, the distribution of different inorganic pigments and organic binder materials in an unknown sample was mapped and correctly classified using the developed RDF. This study represents the first approach for the classification of modern and contemporary materials using LIBS combined with two different multivariate analyses. Subsequent optimization of measurement parameters and data processing will be considered in order to extend its employment to other artistic materials and conservation treatments.
关键词： Laser-induced breakdown spectroscopy,Inorganic pigments,Random decision forest,Organic binders,Principal component analysis
更新于2025-09-23 15:19:57
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Current status and future perspectives for localizing the solar photovoltaic industry in the Kingdom of Saudi Arabia
摘要： Saudi Arabia has developed Saudi Vision 2030, an ambitious plan to reduce the country’s dependence on oil by supporting promising private energy organizations and by developing opportunities that contributes to the national economy. In the manufacturing sector, the government is encouraging technology transfers in the renewable energy industries. It is expected to result in the localization of significant parts of the renewable energy value chain in Saudi Arabia. Solar energy systems are proven renewable energy source globally and domestically, it has its long and vast share of experience, from operations and maintenance, to solar data monitoring and gathering. Wide areas had been identified, where this technology can be highly installed and integrated. Components can be manufactured from locally available raw materials to achieve the final products. This study analyzed the key elements of the value chain for producing crystalline silicon solar photovoltaic systems. This paper presents recommendations for localizing this industry in the Kingdom of Saudi Arabia to align with the goals of Saudi Vision 2030. Although these recommendations are based on the environmental conditions of Saudi Arabia, such are also highly relevant for further application to other countries in the Middle East and North Africa region, where widespread energy transitions from fossil fuels to renewable resources are already taking place.
关键词： Saudi Vision 2030,Crystalline silicon,Localization,Value chain,Cost breakdown,Photovoltaic (PV)
更新于2025-09-23 15:19:57
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Lens-to-sample distance effect on the quantitative analysis of steel by laser-induced breakdown spectroscopy
摘要： The focusing position of the laser affects the characteristics of the laser-induced plasma, which in turn influences the signal stability and the quantitative analysis of laser-induced breakdown spectroscopy. In this study, six standard alloy steels are used as the samples, and the trace elements including Si, Mn, Cr are quantitatively analyzed by internal standard method. The variations of line intensity, background noise intensity, signal-to-background ratio (SBR), detecting sensitivity and detection of limit (LOD) of the element with lens-to-sample distance (LTSD) were investigated. The results show that both the intensities of the analytical line and the background noise reached a maximum when the LTSD is 94 mm. While the corresponding SBR is relatively low. For quantitative analysis, it is observed that the change of the detection sensitivity with LTSD has the similar trend with that of SBR. That is, the detection sensitivity has a lower value when the LTSD is 94mm. However, when the LTSD changes from 93mm to 99mm, LODs of the three elements are maintained at a small value. The present results indicate that for quantitative analysis of LIBS, the intensities of the analytical line and the background noise should be comprehensively considered when optimizing the laser focusing position.
关键词： Laser-induced breakdown spectroscopy,Quantitative analysis,Line intensity,Lens-to-sample distance
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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OPTIMIZED DISTANCE FOR NON-DAMAGING IN LASER CLEANING PREPARATION
摘要： Laser Technology has wide application in industry as well as in scientific research. Semiconductor industry also interested to use laser for cleaning contaminant. However, until today, no laser has been deployed to take over the traditional method due to lack of intension on it. As a first step to embark into industrial solution, initiative has been carried out to do fundamental experiment. Optimization has been established to find out the best position for cleaning without associated with damage. A Q-switched Nd:YAG laser was focused to create breakdown in the air. This is an indicator for plasma formation and shock wave generation as the main mechanisms of damage. Pure aluminium was used as a substrate and mounted on précised a 3D linear translational stage. The defocused distance was varied in the range of 0-25 mm. The damage image was recorded and analysed via the aid of ImageJ software. Small and deep dense deformation was observed as the target located at the focal point. As the defocused distance move further away, the damage tend to be eliminated and its depth approaching the same level as original.
关键词： breakdown,optimization,Damage,Nd:YAG laser,depth,distance
更新于2025-09-23 15:19:57
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Determination of Lead and Chromium in Aloe Vera Pulp and Aloe Vera-Based Cosmetics by Laser-Induced Breakdown Spectroscopy (LIBS)
摘要： This study focuses on the application of laser-induced breakdown spectroscopy (LIBS) to determine lead and chromium in pristine aloe vera and aloe vera based beauty soaps using the second harmonic (532 nm) of a Q-switched Nd:YAG laser. The optimal experimental conditions were evaluated to improve the sensitivity of the detection system by a parametric dependence study. The atomic transition lines at 405.7 nm and 425.4 nm were used as the analytical lines to determine lead and chromium, respectively. The LIBS system was calibrated for these toxic elements and the samples under analysis included 8.00–15.00 ppm by mass of lead and 5.00–12.00 ppm by mass of chromium, which are far above the safe permissible levels of these elements (i.e., 0.50 ppm for Pb and 1.00 ppm for Cr). The quantitative results were checked before and after normalization with the background and better outcomes were obtained when the spectrum was normalized with the background. The LIBS results were compared to the outcomes of selected samples by a standard analytical method, inductively coupled plasma – optical emission spectroscopy (ICP-OES). Both outcomes were in outstanding conformity implying the reliability of the LIBS measurements. The current study is attractive for the general evaluation of human health and specifically for the analysis of aloe vera based cosmetics.
关键词： chromium,Laser-induced breakdown spectroscopy (LIBS),aloe vera,lead
更新于2025-09-23 15:19:57
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Comparative identification of citrus huanglongbing by analyzing leaves using laser-induced breakdown spectroscopy and near-infrared spectroscopy
摘要： In this work, laser-induced breakdown spectroscopy (LIBS), near-infrared spectroscopy (NIR), and LIBS joint NIR (LIBS–NIR) were investigated for the identification of citrus huanglongbing (HLB). The content of minerals like calcium (Ca), zinc (Zn), and potassium (K) was obtained by atomic absorption spectroscopy (AAS). The spectra of LIBS, NIR, and LIBS–NIR were operated by discriminating analysis (DA) and multi-layer perception (MLP). The results of AAS and Kolmogorov–Smirnov Test (K–S test) showed that the Ca and Zn decreased significantly in HLB infected leaves, but K is not significantly influence by HLB. The LIBS–NIR combining with MLP-PCA had highest diagnostic accuracy of 89.5% and 95.7% in training and test set, respectively. These results proved that joint spectrum of LIBS–NIR is a feasible method to identify citrus HLB.
关键词： laser-induced breakdown spectroscopy,minerals,identification,citrus huanglongbing,near-infrared spectroscopy
更新于2025-09-23 15:19:57
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Fast Quantification of Honey Adulteration with Laser-Induced Breakdown Spectroscopy and Chemometric Methods
摘要： Honey adulteration is a major issue in food production, which may reduce the effective components in honey and have a detrimental effect on human health. Herein, laser-induced breakdown spectroscopy (LIBS) combined with chemometric methods was used to fast quantify the adulterant content. Two common types of adulteration, including mixing acacia honey with high fructose corn syrup (HFCS) and rape honey, were quantified with univariate analysis and partial least squares regression (PLSR). In addition, the variable importance was tested with univariable analysis and feature selection methods (genetic algorithm (GA), variable importance in projection (VIP), selectivity ratio (SR)). The results indicated that emissions from Mg II 279.58, 280.30 nm, Mg I 285.25 nm, Ca II 393.37, 396.89 nm, Ca I 422.70 nm, Na I 589.03, 589.64 nm, and K I 766.57, 769.97 nm had compact relationship with adulterant content. Best models for detecting the adulteration ratio of HFCS 55, HFCS 90, and rape honey were achieved by SR-PLSR, VIP-PLSR, and VIP-PLSR, with root-mean-square error (RMSE) of 8.9%, 8.2%, and 4.8%, respectively. This study provided a fast and simple approach for detecting honey adulteration.
关键词： partial least square regression,laser-induced breakdown spectroscopy,adulteration,feature variable,honey
更新于2025-09-23 15:19:57