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Structural, morphological, composition and optical properties of undoped zinc oxide thin films prepared by spray pyrolysis method: effect of solution concentrations
摘要： The aim of this paper is the study of transparent undoped zinc oxide thin films obtained by spray pyrolysis technique on glass substrates heated at 350 °C from 0.1 to 0.4 mol solution concentrations using zinc acetate dehydrate as precursor. The X-ray diffraction patterns and Raman spectrometry with respect to Urbach energy and wurtzite structure, show that the maximum value of the high frequency intensity E2 and the optimal value of the optical gap are obtained at 0.2 mol concentration. Furthermore, an appropriate transparency is obtained and that makes these films suitable for photovoltaic windows layer cells.
关键词： X-ray diffraction,ultraviolet transmission spectroscopy,Raman spectroscopy,spray pyrolysis,undoped zinc oxide
更新于2025-09-23 15:23:52
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X-ray photoelectron spectroscopy and Raman microscopy of a ferroan platinum crystal from the Kondyor Massif, Russian Far East
摘要： X-ray Photoelectron Spectroscopy was used to study a ferroan platinum crystal from the Kondyor Massif, Russian Far East. Prior to the X-ray Photoelectron Spectroscopic analyses, the nature of the crystal was confirmed by X-ray diffraction. The survey scan showed mainly the presence of Pt and Fe, with smaller amounts of O and Si. The high resolutions spectra of the Pt 4f and Fe 2p showed 18.3 atom% Fe in the crystal, which puts the composition on the lower boundary for ferroan platinum and confirms earlier analyses using other methods such as Scanning Electron Microscopy-Energy Dispersive X-ray analysis/microprobe. The binding energy of the Pt 4f5/2 was 74.0 eV and Pt 4f7/2 70.5 eV, while the Fe 2p3/2 for metallic Fe was observed at 707.2 eV. The Fe 2p3/2 for metallic Fe was significantly sharper than that of Fe 2p3/2 at 710.7 eV associated with surface material. The Raman spectrum was dominated by the Pt–Pt stretching mode at 253 cm?1. Changed orientation resulted in the observation of two bands at 127 and 139 cm?1, interpreted as being due to stretching modes of two Pt–Pt bonds with the third bond to Fe and Pt fixed. The presence of Ca-Fe-Al-Mg-Si-O on the surface was probably associated with the presence of a clinopyroxene. These minerals can be expected since the crystal came originally from a clinopyroxenite-dunite matrix. The spectra showed a variety of interferences, e.g. Al 2p with Pt 4f, Mg 2p with Fe 3p, and Ca 2p1/2 with Mg Auger, making exact determinations of the ratios of these elements difficult.
关键词： surface chemistry,platinum group minerals,X-ray photoelectron spectroscopy,Raman spectroscopy,Platinum
更新于2025-09-23 15:23:52
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Raman Spectroscopic and Microscopic Analysis for Monitoring Renal Osteodystrophy Signatures
摘要： Defining the pathogenesis of renal osteodystrophy (ROD) and its treatment efficacy are difficult, since many factors potentially affect bone quality. In this study, confocal Raman microscopy and parallel statistical analysis were used to identify differences in bone composition between healthy and ROD bone tissues through direct visualization of three main compositional parametric ratios, namely, calcium content, mineral-to-matrix, and carbonate-to-matrix. Besides the substantially lower values found in ROD specimens for these representative ratios, an obvious accumulation of phenylalanine is Raman spectroscopically observed for the first time in ROD samples and reported here. Thus, elevated phenylalanine could also be considered as an indicator of the disease. Since the image results are based on tens of thousands of spectra per sample, not only are the average ratios statistically significantly different for normal and ROD bone, but the method is clearly powerful in distinguishing between the two types of samples. Furthermore, the statistical outcomes demonstrate that only a relatively small number of spectra need to be recorded in order to classify the samples. This work thus opens the possibility of future development of in vivo Raman sensors for assessment of bone structure, remodeling, and mineralization, where different biomarkers are simultaneously detected with unprecedented accuracy.
关键词： Raman spectroscopy,bone composition,statistical analysis,renal osteodystrophy
更新于2025-09-23 15:23:52
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The Raman spectra of the Na <sub/>2</sub> SO <sub/>4</sub> -K <sub/>2</sub> SO <sub/>4</sub> system: Applicability to soluble salts studies in built heritage
摘要： The Raman spectra of the Na2SO4‐K2SO4‐H2O system are not well‐defined in the literature. Specifically, the proper identification of sodium and potassium sulphate (aphthitalite or glaserite, K3Na(SO4)2) and anhydrous sodium sulphate (thenardite, Na2SO4) is particularly problematic because their vibrational profiles present the same main Raman peak at 993 cm?1 and very similar low frequency bands. As proved in bibliography, the similarity of their spectra can often lead to uncertain or erroneous identifications. Considering that aphthitalite and thenardite can be found as degradation products on built heritage materials and the degree of danger associated to them is not the same, being the second one the most harmful, the resolution of this problem has a critical importance. For this reason, in the present work, the Raman spectra of aphthitalite and thenardite are deeply studied to identify the vibrational fingerprints enabling their correct identification. The results here summarized and provided by two different Raman instruments highlight that the spectrum of aphthitalite displays characteristic bands at 1,084 and 1,202 cm?1. In contrast, the bands at 1,100, 1,129, and 1,152 cm?1 seem to be characteristic of thenardite. Furthermore, when those secondary bands are not observed or mixtures of both compounds are present, the ratio between their most intense bands at 452 and 993 cm?1 is the key for their correct characterization. On the whole, this study fills the gaps observed in literature and gives the solution for the correct identification of aphthitalite and thenardite even when secondary bands are not observed.
关键词： mirabilite,glaserite,aphthitalite,thenardite,Raman spectroscopy
更新于2025-09-23 15:23:52
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Phage-based assay for rapid detection of bacterial pathogens in blood by Raman spectroscopy
摘要： Sepsis is a systemic inflammatory response ensuing from presence and persistence of microorganisms in the bloodstream. The possibility to identify them at low concentrations may improve the problem of human health and therapeutic outcomes. So, sensitive and rapid diagnostic systems are essential to evaluate bacterial infections during the time, also reducing the cost. In this study, from random M13 phage display libraries, we selected phage clones that specifically bind surface of Staphyloccocus aureus, Pseudomonas aeruginosa and Escherichia coli. Then, commercial magnetic beads were functionalized with phage clones through covalent bond and used as capture and concentrating of pathogens from blood. We found that phage-magnetic beads complex represents a network which enables a cheap, high sensitive and specific detection of the bacteria involved in sepsis by micro-Raman spectroscopy. The enter process required 6 h and has the limit of detection of 10 Colony Forming Units on 7 ml of blood (CFU/7 ml).
关键词： Phage-capture system,Raman spectroscopy,M13 filamentous phage,Sepsis,Phage display
更新于2025-09-23 15:23:52
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Raman/XRF/EDX microanalysis of 2nd-century stuccoes from Domus Valeriorum in Rome
摘要： 2nd-century stucco fragments from the roman Domus Valeriorum were analyzed by Raman spectroscopy (Raman), imaging X-ray fluorescence (XRF) and energy dispersive X-ray microanalysis (EDX) in order to identify the pigments and materials thereon. Cinnabar, malachite, hematite, goethite and Egyptian blue were detected by the synergistic use of these techniques whereas calcite, with some traces of gypsum, was detected as materials for the bas-relief figures and the pictorial background. This non-destructive characterization is the first carried out on the Domus Valeriorum finds. The multi-analytical approach highlighted the complementarity and versatility of these techniques, suitable for both laboratory and in-situ analysis, on macroscopic or microscopic fragments without preliminary manipulation.
关键词： Energy dispersive X-ray fluorescence,X-ray fluorescence imaging,Domus Valeriorum,Pigments,Raman spectroscopy
更新于2025-09-23 15:23:52
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Flow cytometry and micro-Raman spectroscopy: Identification of hemocyte populations in the mussel Mytilus galloprovincialis (Bivalvia: Mytilidae) from Faro Lake and Tyrrhenian Sea (Sicily, Italy)
摘要： Immunological and structural characteristics of hemocyte populations in the mussel Mytilus galloprovincialis (Bivalvia: Mytilidae), going from two different Sicilian habitats (Faro Lake and Tyrrhenian sea), was investigated by means of two different techniques (flow cytometric and micro-Raman spectroscopy analyses). For this purpose, three hundred and sixty mussels Mytilus galloprovincialis were analyzed during November 2017. They were divided into two equal groups (triplicate sample) on the basis of the site of collection (n = 60 caught in Faro Lake - group A, and n = 60 caught in Tyrrhenian Sea - group B). Some several differences between the species of Faro Lake and Tyrrhenian Sea are observed and ascribed to the disruption of immune parameters induced by the variations of some qualitative water parameters (temperature, salinity, dissolved oxygen, pH, ammonium 10, free chlorine, total chlorine, total phosphate, orthofhosphate) recorded in the two habitats. This study is relevant for monitoring the conditions of the sea and Faro Lake, which is strongly influenced by the currents of the Tyrrhenian Sea. Faro lake is well known for the cultivation of mussels and this is part of a coastal habitat of particular interest, consisted of a peculiar biocenotic complex. Further, for the first time, significant different arrangement in the mussels cell structural organization was evidenced by simply following their highly reproducible Raman biomolecular signatures.
关键词： Hemocyte,Bivalve immunology,Deep-sea,Mussel Mytilus galloprovincialis,Flow cytometry,Raman spectroscopy
更新于2025-09-23 15:23:52
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Development and first in-human use of a Raman spectroscopy guidance system integrated with a brain biopsy needle
摘要： Navigation-guided brain biopsies are the standard of care for diagnosis of several brain pathologies. However, imprecise targeting and tissue heterogeneity often hinder obtaining high-quality tissue samples, resulting in poor diagnostic yield. We report the development and first clinical testing of a navigation-guided fiberoptic Raman probe that allows surgeons to interrogate brain tissue in situ at the tip of the biopsy needle, prior to tissue removal. The 900μm diameter probe can detect high spectral quality Raman signals in both the fingerprint and high wavenumber spectral regions with minimal disruption to the neurosurgical workflow. The probe was tested in 3 brain tumor patients, and the acquired spectra in both normal brain and tumor tissue demonstrated the expected spectral features, indicating the quality of the data. As a proof-of-concept, we also demonstrate the consistency of the acquired Raman signal with different systems and experimental settings. Additional clinical development is planned to further evaluate the performance of the system and develop a statistical model for real-time tissue classification during the biopsy procedure.
关键词： biopsy,cancer,neurosurgery,optical systems,Raman spectroscopy,medical imaging
更新于2025-09-23 15:23:52
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Optical thickness identification of few-layer MoS <sub/>2</sub> deposited by chemical vapor deposition
摘要： The physical and optoelectronic properties of MoS2 are closely related to their thickness. Few-layer molybdenum disulfide (MoS2) has been intensively studied for its potential applications. In this work, monolayer and few-layer MoS2 nanosheets with large size and high crystallization quality were successfully prepared by chemical vapor deposition (CVD). Then, the layer number of CVD-grown MoS2 nanosheets were identified for the first time by extracting the R channel contrast of the optical image of the sample with ImageJ software. Compared with Raman spectra and PL spectra, this method can identify the layer number of CVD-grown MoS2 nanosheets efficiently and accurately, which provides a simple and feasible method for the study of the layer number of CVD-grown MoS2 nanosheets and can help us exploiting their applications in the future.
关键词： Thickness identification,chemical vapor deposition,MoS2,optical microscopy,Raman spectroscopy
更新于2025-09-23 15:23:52
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Multivariable study on growth of diamond on diamond substrates by microwave? plasma chemical vapour deposition
摘要： Substrate temperature and methane concentration in Hydrogen (H2) gas mixture is the main source for increasing the growth rate, nucleation and grain size of a synthetic diamond. The downside of such an approach is reduced quality. By increasing the chamber pressure, although the quality can be improved, however, it leads to a decrease in the crystal growth rate. Thin diamond films were deposited under hydrogen (H2) and methane (CH4) gas mixture using microwave plasma chemical vapor deposition (MPCVD) technique. The effect of methane concentration (1-5%), growth temperature, and pressure on the nucleation of diamond thin films on diamond substrates was investigated. The growth temperature and pressure were maintained in the range of 925-950 ℃ and 72-75 Torr, respectively. Single crystal diamond (SCD) thin films have been prepared on diamond substrates, which play an important role in the application of the diamond detectors. Different dimensions of films were obtained on diamond substrates with different thicknesses such as 209.17 μm, 401.73 μm, and 995.03μm for the sample with 1%, 2% and 5% of methane concentration respectively. The roughness, as well as growth rate of these films, were also investigated and were found to be 5.02 μ/h and 4.23 nm, respectively for 5% methane by optimizing the substrate temperature at 950 ℃. Different characterization techniques were used to study the structural, morphological, and compositional properties of the deposited diamond films which confirmed the crystallographic order of the developed diamond film on the diamond substrates.
关键词： MPCVD,XRD,Diamond thin films,XPS,Raman spectroscopy,AFM,SEM
更新于2025-09-23 15:23:52