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Portable, visual, and nondestructive detector integrating Vis/NIR spectrometer for sugar content of kiwifruits
摘要： A portable sugar content detector for intact kiwifruits was developed using a visible/near-infrared spectrometer over the wavelength of 350–1,100 nm as spectra collector, a tablet computer as controller, a micro-halogen lamp as light source, and a self-made “Y” shape optical fiber as light transmitter and light receiver. The software applied to collect spectra, to establish sugar content prediction model, and to predict sugar content of kiwifruits was developed by Java language. Partial least square regression model was established to determine sugar content of kiwifruits. Contrasted with the sugar content obtained by digital refractometer, the root-mean-square error of the developed detector was 0.93% in soluble solids content. The obtained sugar content using the developed detector could be given in 2.5 s. The study shows that the developed portable sugar content detector is a promising tool for on-site or in field nondestructive measurement on sugar content of kiwifruits.
关键词： kiwifruits,portable detector,Vis/NIR spectrometer,nondestructive measurement,sugar content
更新于2025-09-23 15:23:52
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Optical spectroscopy of the Au4+ cluster: Resolved vibronic structure indicates an unexpected isomer**
摘要： The knowledge of the geometric and electronic structure of gold clusters and nanoparticles is vital for understanding their catalytic and photochemical properties at the molecular level. Herein, we report the vibronic optical photodissociation spectrum of cold and mass-selected Au4+ clusters measured at a resolution high enough to allow for comparison with Franck-Condon simulations of the excited state transitions based on time-dependent density functional theory calculations. The three vibrational frequencies identified for the lowest-lying optically accessible excited state at 2.17 eV stem from the Y-shaped isomer (C2v) and not from the rhombic isomer (D2h) that is considered to be the ground state structure of Au4+. This study demonstrates that an analysis of low-resolution electronic spectra by calculations of vertical transitions alone is not sufficient for a reliable isomer assignment of such metal clusters.
关键词： gold,UV/Vis spectroscopy,structure elucidation,cluster compounds,electronic structure
更新于2025-09-23 15:23:52
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Vis-NIR light-responsive photocatalytic activity of C3N4-Ag-Ag2O heterojunction-decorated carbon-fiber cloth as efficient filter-membrane-shaped photocatalyst
摘要： C3N4-decorated carbon-fiber (CF) cloth has been demonstrated to be a filter-membrane-shaped photocatalyst for degrading flowing wastewater, but it can be excited only by visible light (λ < 450 nm). To extend the photoresponse range to NIR region, herein we have designed and prepared C3N4-Ag-Ag2O heterojunctions on CF cloth. The growth of C3N4 nanosheets (thickness: 20-30 nm) on CF cloth is realized by a thermal condensation method, and then Ag/Ag2O nanoparticles (10-20 nm) are deposited on CF/C3N4 cloth by a chemical precipitation method. CF/C3N4/Ag/Ag2O cloth exhibits excellent flexibility and strong photoabsorption in a broad Vis-NIR region (400-1400 nm), wider than CF/C3N4 (absorption edge: 450 nm). Under the irradiation of 808 nm or 980 nm laser, CF/C3N4/Ag/Ag2O cloth can remove 83%/41% AO7 and 72%/38% 4-CP in 140 min respectively, significantly higher than those (33%/13% AO7 and 31%/10% 4-CP) by CF/Ag/Ag2O cloth and those (3%/1% AO7 and 0%/1% 4-CP) by CF/C3N4 cloth. Interestingly, when CF/C3N4/Ag/Ag2O cloth is used as the filter-membrane to photo-degrade the flowing wastewater (AO7, 20 mg L-1, rate: 1.5 L h-1), the removal efficiency of AO7 reaches up 97% after 8 grade reactors. Therefore, CF/C3N4/Ag/Ag2O cloth can be used as an efficient filter-membrane-shaped photocatalyst with NIR photoresponse.
关键词： CF/C3N4/Ag/Ag2O cloth,nanosheets,photocatalysis,nanoparticles,Vis-NIR
更新于2025-09-23 15:22:29
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The examination of molecular structure properties of 4,4′-oxydiphthalonitrile compound: combined spectral and computational analysis approaches
摘要： The synthesis process, X-ray diffraction analysis of its single crystal form and the structural properties of the 4,4'-oxydiphthalonitrile compound by Fourier transform infrared, nuclear magnetic resonance and ultraviolet-visible spectral methods were reported in this study. Density functional theory studies of the compound were carried out by designed modeling with the Becke three-parameter hybrid functional combined with Lee-Yang-Parr correlation functional and 6-311G(d,p) basis set. Some molecular structure parameters obtained theoretically were compared with those obtained from the crystallographic analysis. Vibrational modes and wavenumbers with the aid of the potential energy distribution analysis, carbon and proton chemical shift values with diversified approaches and absorption wavelengths using Time-Dependent Density Functional and Conductor-Like Polarizable Continuum Model in different solvent media were examined theoretically. The compatibility of spectral and theoretical results was evaluated by examining the correlation coefficients. In addition, the frontier molecular orbitals energies, global reactivity parameters, molecular electrostatic potential map, the potential for non-linear optical material and some thermodynamic parameters at different temperature values of the 4,4'-oxydiphthalonitrile compound were investigated at the same theoretical level.
关键词： DFT,phthalonitrile,FT-IR,NMR,UV-Vis
更新于2025-09-23 15:22:29
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Structural, energetic and spectroscopic studies of new luminescent complexes based on 2-(2′-hydroxyphenyl)imidazo[1,2- <i>a</i> ]pyridines and 1,2-phenylenediboronic acid
摘要： Three new blue-luminescent complexes of selected imidazo[1,2-a]pyridine derivatives and 1,2-phenylenediboronic acid have been synthesized and structurally characterized using single-crystal X-ray diffraction. Additionally, the crystal structures of two of the (N,O)-donor compounds have been evaluated for the first time. The crystal packing and molecular motifs observed in the studied crystals have been thoroughly analysed, including computational studies, and are also discussed within the context of analogous systems reported in the literature. It appears that the new compounds form different crystal networks with regard to the asymmetric unit content and packing, although some similarities can be found. In all cases a typical centrosymmetric dimer bound via boronic acid groups is formed, characterized by an interaction energy of about -80 kJ mol-1, while the 2-(2'-hydroxyphenyl)imidazo[1,2-a]pyridine complex and its methoxy derivative form solvate structures, somewhat resembling the previously studied 8-oxyquinolinate analogues. As far as the spectroscopic properties are concerned, the lowest energy excitation observed in the studied complexes is based on the highest occupied molecular orbital–lowest unoccupied molecular orbital transition, and both these molecular orbitals are centred predominantly on the (N,O)-donor species according to the results of time-dependent density functional theory. Thus, the charge transfer observed for the 8-oxyquinolinate equivalents does not occur in these cases. Consequently, the spectroscopic behaviour of the series is very much comparable with that of the parent imidazo[1,2-a]pyridine derivatives, if the excited-state intramolecular proton-transfer process does not take place, as shown by the absorption and emission spectra collected in toluene and acetone solutions. Complexation causes a reduction in the Stokes shift compared with the respective (N,O)-donor molecules.
关键词： periodic calculations,TDDFT,UV–Vis spectroscopy,X-ray diffraction,time-dependent density functional theory,spectroscopic properties,luminescent boron complexes,transferred aspherical atom model (TAAM) refinement
更新于2025-09-23 15:22:29
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Improved Photocatalytic Properties of NiS Nanocomposites Prepared by Displacement Method for Removal of Rose Bengal Dye
摘要： Objective: The present work describes NiS nanoparticles were prepared by chemical displacement method using CTAB as a stabilizer. Method: For the source of Sulfide ion, we used thioacetamide as fuel and nickel nitrate as metal salt. NiS nanoparticles are p-type semiconductor. Band gap of NiS is 0.5- 0.6 eV and also reported to be a good photo catalyst in the degradation of pollutants. The structural, morphological, metal percentage and optical properties of as synthesized nanoparticles are investigated by using X-ray diffraction (XRD), UV-Visible spectra; Field emission gun scanning electron microscopy (FEG-SEM) with EDS, Fourier transforms infrared spectroscopy (FTIR), High-resolution transmission electron microscopy (HR-TEM) and Photoluminescence spectroscopy (PL). Results: The x-ray diffraction patterns revealed that the particles exhibited a crystal structure at the suitable temperature. The average particle size of the nanoparticles from the X-ray diffraction is about 22.8 nm and also Field emission gun scanning electron microscopy shows good morphology and exhibited clearly hexagonal shape. Conclusion: The Transmission electron microscopy (HR-TEM) shows the crystalline size of structures is 22 nm. Further, the Photocatalytic activity of Synthesized NiS nanoparticles was investigated by photo catalytic removal of Rose Bengal as a model of organic pollutant. It shows good photocatalytic activity against Rose Bengal dye (98.1%).
关键词： Nanoparticles,UV-Vis,FEG-SEM,EDAX,XRD,FTIR,HR-TEM,nickel sulfide
更新于2025-09-23 15:22:29
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In situ Determination of Nitrate and Hydrogen Sulfide in the Baltic Sea Using an Ultraviolet Spectrophotometer
摘要： Evaluating the health status of marine ecosystems becomes ever increasingly important especially against the backdrop of rising pressures from human activities. This is true especially for coastal seas such as the Baltic Sea that is surrounded by highly industrialized countries. Nutrients and pollutants such as nitrate and hydrogen sulfide, which have a major impact on ecosystem functioning, are two of several indicators for assessing the status of natural waters, and therefore key environmental of considerable interest. The frequency and the spatial coverage of the nitrate and hydrogen sulfide measurements are currently limited by the cost of the laboratory analysis and personnel. Optical in situ sensors can help to overcome this challenge by allowing reagentless and fast detection of dissolved chemical species. A chemical-free optical sensor has been used for direct and simultaneous measurements of both key parameters, and the results were compared with traditional methods. The data were collected during an observational program conducted in the Baltic Sea in February 2018. We used the OPUS UV spectral sensor, which was deployed for the first time in coastal waters, in combination with a deep-sea telemetry system to enable near-real time measurements during CTD profiling. Data processing was carried out using a multiple linear regression procedure. Measurements from both OPUS and on-board analysis were in good agreement. The results showed, that in situ UV-VIS spectrophotometry provides the capability to determine the concentration distributions of nitrate and hydrogen sulfide in the brackish waters of the Baltic Sea.
关键词： sulfide,Baltic Sea,monitoring,hypoxia,nutrients,UV-VIS spectrophotometry
更新于2025-09-23 15:22:29
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Phase Evaluation of Pure Nanocrystalline Barium Stannate by Two Different Milling Activations
摘要： Pure nanocrystalline BaSnO3 is prepared by two methods: mechanical activation (planetary ball milling) and mechanical hand mixing in agate mortar followed by sintering for both at 1350 °C/ 2 h. The phase formations during synthesis are analyzed by x-ray diffraction (XRD) studies and the crystallite size is measured by Scherrer’s formula from the major peaks of the diffractogram. The nanocrystalline barium stannate having single phase simple cubic perovskite structure is synthesized with a crystallite size about 50 nm. Fourier transform infrared spectroscopy (FTIR) is done to determine symmetric and asymmetric stretching of the bonds formed and co-ordination of the ions within crystal structure. FTIR studies justify the phases developed by XRD since the molecular signature and co-ordination of cations are verified. Microstructure and morphology are observed by scanning electron microscopy (SEM), while energy dispersive x-ray analysis (EDX) is done to determine the presence of the required element of composition formation. Ultra violet-visible spectroscopy (UV-VIS) shows absorption spectra of the sample within the UV region, while the band gap is calculated using the Tauc relation. The band gap evaluated for nanocrystalline barium stannate is about 2–2.78 eV for indirect transition, while for direct transition it is about 2.78–3.14 eV. The value is observed to be close to that of semiconductor-based materials.
关键词： FTIR,UV-VIS,nanocrystalline barium stannate,EDX,high energy planetary milling,XRD,SEM
更新于2025-09-23 15:22:29
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[IEEE 2018 25th IEEE International Conference on Image Processing (ICIP) - Athens, Greece (2018.10.7-2018.10.10)] 2018 25th IEEE International Conference on Image Processing (ICIP) - Realistic Texture Reconstruction Incorporating Spectrophotometric Color Correction
摘要： With the proliferation of high resolution 3D scanners, the quality of recorded 3D models has greatly improved. Nonetheless, while geometric fidelity is important, color information is still required to achieve photo-realistic 3D models. In this regard, texture reconstruction techniques combine color images from several views in order to optimally color the mesh of a 3D model. Nonetheless, a major challenge that is often overlooked by existing approaches is the technical limitations of color acquisition devices that lead to erroneously colored 3D models. In this paper, a novel technique is presented that formulates texture reconstruction as an optimization problem incorporating a color correction term in its objective function. The underlying rationale is to exploit external to the 3D scanner color measurements that can be available from more reliable sensors such as a UV-VIS spectrometer. Such measurements are often available for objects of high aesthetic value such as artworks of cultural heritage objects. Through experimental evaluation of our method on a real painting we demonstrate the superiority of the proposed technique, compared to state-of-the-art texture reconstruction, providing a reliable representation of the artworks appearance both in terms of numerical accuracy and visual observation.
关键词： cultural heritage,3D reconstruction,UV-VIS spectrometer,color correction,Texture reconstruction
更新于2025-09-23 15:22:29
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UV-visible scanning spectrophotometry and chemometric analysis as tools for carotenoids analysis in cassava genotypes (Manihot esculenta Crantz)
摘要： In this study, the metabolomics characterization focusing on the carotenoid composition of ten cassava (Manihot esculenta) genotypes cultivated in southern Brazil by UV-visible scanning spectrophotometry and reverse phase-high performance liquid chromatography was performed. Cassava roots rich in β-carotene are an important staple food for populations with risk of vitamin A deficiency. Cassava genotypes with high pro-vitamin A activity have been identified as a strategy to reduce the prevalence of deficiency of this vitamin. The data set was used for the construction of a descriptive model by chemometric analysis. The genotypes of yellow-fleshed roots were clustered by the higher concentrations of cis-β-carotene and lutein. Inversely, cream-fleshed roots genotypes were grouped precisely due to their lower concentrations of these pigments, as samples rich in lycopene (red-fleshed) differed among the studied genotypes. The analytical approach (UV-Vis, HPLC, and chemometrics) used showed to be efficient for understanding the chemodiversity of cassava genotypes, allowing to classify them according to important features for human health and nutrition.
关键词： Chemometrics,cassava genotypes,partial metabolome,descriptive models,UV-vis,carotenoids,RP-HPLC
更新于2025-09-23 15:22:29