Spectroscopy of a mixture of atomic cesium with molecular nitrogen gas in a nanocell was studied for the first time. An optical nanocell with a thickness of L ~ 800 nm was used to measure the broadening and shift of the D₂ line of Cs atoms by gaseous nitrogen (N₂) under the pressure of 400 Torr. The absorption spectra of pure cesium vapor and cesium vapor with the addition of gaseous nitrogen were measured. The measured values of the shift and broadening of the D₂ lines of cesium in the presence of N₂ were –7 ± 1 and 15 ± 0.7 MHz/Torr. The results are in good agreement with the values given in the literature.

Composites based on phenolic and urethane polymers were studied using spectral and thermographic methods. Boric acid was used as a modifier. Quantum chemical calculations of fragments simulating the structure of composites were carried out using the density functional theory method. It has been suggested that the increase in heat resistance and decrease in flammability of foamed modified polymers is due to the chemical interaction of the polymer matrix with the modifier. In this case, the formation of a supramolecular structure of a urethane polymer occurs due to binding through the boroxide group, while the formation of boroxine fragments is characteristic of the phenolic polymer.

A generalized method has been developed to describe the time dependences of the orientation factor for the Förster resonance dipole-dipole energy transfer (FRET) between fluorescent labels associated with biomolecules, taking into account internal rotational mobility. The method consists in representing the orientation factor in terms of tensor orientational correlation functions for vectors of transition dipole moments of donor and acceptor, which makes it possible to use well-known proven models of orientational relaxation to describe rotational diffusion. The time dependences of the probability of the energy transfer process on the opening angles of internal rotational diffusion cones, the orientation of these cones on the surface of the biomolecule, and the rotational diffusion rates are calculated. The ranges of values of the angular parameters are determined, at which the temporal kinetics has the most dramatic changes during the transition from the initial stationary values to the dynamic limit. It has been demonstrated that the internal rotational diffusion of the donor and acceptor, under certain conditions, can both decrease and increase the probability of energy transfer over time.

Method for determining the concentrations of mixture components from their optical absorption spectra in the presence of Rayleigh scattering is proposed. The differential evolution method was used to calculate the concentrations of components. It was used to minimize the difference between experimental and calculated spectra. To demonstrate the performance of the method, the concentrations of the components of the model mixture were determined from its optical absorption spectrum. This model mixture included five azo dyes with significantly overlapping absorption spectra and a noticeable light scattering contribution. The influence of the absorption spectrum errors on the errors of component concentrations was evaluated. Without light scattering both the multiple linear regression method and the method of differential evolution give the results of determination of the component concentrations coinciding within the measurement accuracy. It is reasonable to use the method of differential evolution for spectrophotometric determination of the concentrations of mixture components in the presence of light scattering.

Calculations of bands, densities of states and optical properties of crystals of the isoelectronic series Si, AlP, MgS and NaCl were carried out. The influence of the ionicity of a chemical bond on the electronic structure and optical properties of crystals were established. In particular, the distribution of partial densities of states during the formation of several upper valence bands and several lower conduction bands, the structure of theoretical ɛ2 spectra, the nature of their main maxima and steps, as well as the localization of transitions in the Brillouin zone were studied.

The thickness and optical constants changes of boron oxide films deposited on substrates of sapphire glass, sitall, and polycrystalline massive aluminum were studied directly during heating on air in the temperature range of 24–700°C using single-wave and spectral ellipsometry methods. The high hygroscopicity of these films was demonstrated, which decreases upon their preliminary annealing. It was shown that a continuous decrease of the film thickness occurs in the studied temperature range. In the temperature range up to 300°C, it is due to dehydration processes. At higher temperatures, the decrease in the film thickness is explained by the slow evaporation of boric acid formed in the film. It was shown that the deposition of a boron oxide film on the aluminum surface does not affect the rate of its oxidation.

The drying conditions (in vacuum and in air) for sedimented in ethanol Yb:Y₂O₃ + 5 mol.%ZrO₂ nanoparticles have an impact on the optical quality of ceramic samples made of them, as it has been investigated. The studies were conducted using methods of absorption spectroscopy, both in 200–1100 nm region and mid-infrared region, as well as Raman scattering. It has been shown that, regardless of the drying process for nanopowders, carbonate radicals as well as fragments of ethanol and water are produced in the ceramics, leading to the formation of complex crystalline defects that include divalent ytterbium ions. Due to these defects, the transparency of the ceramics decreases and the photoluminescence of trivalent ytterbium is excited by laser radiation with wavelength of 785 nm. The most significant negative effect of these defects on transparency was observed in ceramics made of nanopowders that were dried in a vacuum.

Fused glasses of Y₂О₃–Al₂O₃–В₂О₃ system with Sb₂O₃ additives have been synthesized and their spectral-luminescent and optical properties have been investigated. It is found that the doping used leads to the appearance of intense UV absorption and a decrease in the optical band gap width and the Urbach energy. Their luminescence is represented by a broad weakly structured band extending from the near-UV to the near-IR spectrum regions and caused by the superposition of ³P₁→¹S₀ bands of different types of Sb³⁺ optical centers and Sb³⁺→Sb⁵⁺ charge transfer band. The quantum yield of such luminescence at room temperature and band-to-band excitation for weakly doped glass is close to 20%. Its decay kinetics at T = 298 K and 77 K have been studied and the reasons preventing the quantum yield increase have been considered.

The effect of light pressure forces of an evanescent electromagnetic wave formed due to total internal reflection at the interface of a dielectric and a liquid on dielectric spherical nanoparticles located in a liquid medium is considered. The phase portraits of the equations of particle transportation by an evanescent field are investigated, taking into account the resistance force of the medium. It is shown that, depending on the parameters of the laser radiation and the material of the nanoparticle suspended in water, various phase portraits can be realized both without special points and with one special point (stable focus or stable node) on the phase plane.

The spectra and structure of the near-surface plasma formation and the torch luminosity were experimentally studied under two-pulse laser action at wavelengths of 1064 and 532 nm on a zirconium target in the air depending on the time interval between laser pulses and their sequence. The dependences of laser plasma temperature on the parameters of paired laser pulses were established at laser radiation power densities of q₁₀₆₄ ≈ 3.1 ∙ 10⁹ W/cm² and q₅₃₂ ≈ 2.7 ∙ 10⁹ W/cm² at wavelengths of 1064 and 532 nm, respectively. It was shown that the optimal conditions for excitation of erosion plasma are provided by the leading action of laser radiation pulses with wavelength of 532 nm and a time interval between laser pulses of 4–5 μs, which is important for increasing the efficiency of laser emission spectral analysis and laser-plasma processing of materials.

Dependence of parameters of time-resolved and steady-state photoluminescence for quantum dots (QD) Ag-In-S2 (AIS) with surface active groups of polyethylenimine (PEI) upon variation of pH of water solutions. It was shown that the high sensitivity of PEI structure to pH in a wide range influences the mobility of charge carriers in AIS QDs and, as a consequence, determines the features of the mechanism of the formation of the dipole moment transition in QDs. Using Stark model and assuming the absence of the electrical field on the QD surface (ZnS shell) in environments with a neutral pH and in ovarian tissues without pathology, it was substantiated that a change in the pH of solutions, both to acidic and alkaline side, causes a change in the electrical field in the local environment of the QD, which manifests itself in changes in the photoluminescence parameters of the QD (band maximum position, intensity, average lifetime). It was found that AIS-PEI QDs under study can act as a contrast agent in clinical morphology. Using confocal microspectrometry, it was shown that AIS-PEI QDs can be used not only for the visualization, but also for screening of ovarian malignancies.

Sodium pyruvate is an important biological compound that being a substrate for several enzymes of the main metabolic pathways of carbohydrates. It has been shown for the first time, that along with well-known antioxidant properties, sodium pyruvate exhibits the ability to act as a photosensitizer when exposed to longwave UV radiation of λ = 325 nm, corresponding to its low-intensity n→π* absorption band. The sensitizing properties of pyruvate have been studied in relation to the lactate dehydrogenase (LDH) enzyme, the substrate of which the pyruvate is. It has been shown that pyruvate-sensitized photodestruction of tryptophan and cystine amino acid residues leads to photoinactivation of the enzyme. The photochemical process is inhibited by adding free radical quenchers and antioxidant enzymes to the irradiated LDH-pyruvate mixture, as well as by replacing H₂O with D₂O; also, the process is accelerated by reducing the concentration of the dissolved oxygen. A conclusion has been made about the decisive role of radical processes (type I reactions) in pyruvate-sensitized photoinactivation of LDH.

The ability of the thermosensitive copolymer dextran-poly-N-isopropylacrylamide (D-PNIPAM) to bind and release the photosensitizer (PS) meta-tetra(hydroxyphenyl)chlorin (mTHPC) was investigated using fluorescence spectroscopy techniques. It is shown that the efficiency of mTHPC molecules sorption by the copolymer depends on its phase state: mTHPC is efficiently adsorbed by D-PNIPAM (copolymer in globular conformation) at temperatures above 34–35 C, but PS is practically not adsorbed on D-PNIPAM (copolymer in coil conformation) at temperatures below 34–35 C. The presence of additional structural rearrangements in the globule of D-PNIPAM under the action of high temperatures (above 45°C) was shown by the method of dynamic light scattering. Comparing the mTHPC dissociation rates from complexes with DPNIPAM formed at 37-60 °C and calculating the mTHPC release rate constants from the polymer globule were performed. It is shown that the high temperature of complexation (45–60 C) of mTHPC with DPNIPAM leads to almost a twofold increase in the rate of PS molecules release from the copolymer globule at physiological temperatures, compared to similar complexes formed at 37–40°C. The time required for thermally induced structural rearrangements in D-PNIPAM has been estimated. The globule-coil transition in the D-PNIPAM molecule caused by temperature decrease below 34–35°C takes less than a minute, while the reversibility of conformational changes in the copolymer globule when the medium temperature rises above 45°C requires about 150 min. The obtained results suggest that thermo-dependent conformational rearrangements in the D-PNIPAM copolymer can be used to efficiently regulate the rate of PS release in cellular and tissue systems.

This paper presents a comparative analysis of existing endoscopic means of Raman spectroscopy. Their capabilities and characteristic limitations are described. A diagram of a promising endoscopic Raman spectrometer based on an acousto-optical deflector and a composite fiber bundle is proposed.

The NMR method was used to study the composition of juice of fruits of different rowan varieties: common rowan (Sorbus aucuparia), Nevezhinskaya (Sorbus Nevezhinskaja), pomegranate (Crataegosorbus Granatnaja). 10 compounds – carbohydrates and organic acids – were spectrally identified and their content was determined. In all samples, sorbitol was mostly represented among carbohydrates, malic acid was mostly represented among acids, and sorbic and parasorbic acids were not detected. Under the influence of low temperatures (–18°C for a month), the sorbitol content in rowan fruits increased, the amount of malic acid decreased, and the content of parasorboside did not change. During the ripening of rowan fruits, an increase in the amount of sorbitol in the juice and a decrease in malic acid and parasorboside were observed, which improves its nutritional qualities.

Er₂O₃ and ruby selective and continual emission spectra in visible and near IR ranges were experimentally investigated under laser-thermal excitation by continuous and pulsed radiation of electric discharge CO₂ lasers at λ = 10.6 μ. Selective spectra are radiated by Er³⁺ and Cr³⁺ions. Continual radiation is thermodynamically equilibrial electromagnetic field in crystalline lattice with proper temperature. Effect of the delay of thermal emission fronts and radiation intensity maxima in oxides with respect to laser pulses is explained by different kinetics of the layer heating and continual radiation.

We present a systematic theoretical investigation of the linear polarizations of the fluorescence radiation of 5s_1/2→np_3/2 (n = 2, 3, 4 where n is the principal quantum number) lines after inner-shell singlephoton ionization of the exemplary Xe atoms and the Xe-like W²⁰⁺ ions by (polarized and unpolarized) incoming photons within the framework of the relativistic approach and density-matrix theory. The correlation between the polarization of the incident light and the polarization of the characteristic radiation is examined. The sensitive dependence of the transfer of the polarization of fluorescence radiation emitted by the photoionization of atoms/ions is thoroughly analyzed. Our results demonstrate that incident light polarization plays a critical role in determining the polarization of fluorescence radiation. Due to polarization transfer, the polarization of the fluorescence radiation significantly changes. Our present results are in agreement with other theoretical and experimental values.

Nanocrystalline CdWO4 particles were synthesized via a co-precipitation method using diethylene glycol (DEG) as a capping agent, followed by a hydrothermal technique. Synthesized samples were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering, Fourier transform infrared spectroscopy, Raman spectroscopy, and UV-visible absorption and photoluminescence analysis. XRD analysis confirmed the formation of a monoclinic structure in CdWO₄. Uniform homogenous NanoRect long rod-like morphologies with lengths of <20 to 300 nm were observed via SEM. Hydrodynamic size distribution of the synthesized particles increased with increasing DEG concentration from 20 to 1500 nm. Raman analysis confirmed the monoclinic structure of the prepared CdWO₄. The width of the strong vibration mode at 897 cm^–1 decreases as the annealing temperature increases, indicating that the crystallite size increases as the crystal evolves with temperature. The band gap of CdWO₄ was found to vary between 2.47 and 4.06 eV from the UV-Vis absorption measurements. Bandgap increases with increasing lattice strain, which is reflected by the calculated XRD results. UV-visible measurements reveal that the bandgap of CdWO₄ increases with strain in the sample. A broad intense emission peak was observed at 482 nm when the samples were excited at 298 nm.

Predicting the oil content of reinjection water is a crucial challenge in the advancement of digital oilfield technologies. To effectively address this challenge, this study investigates rapid and accurate prediction methods for oil content in reinjection water. A total of 146 samples of reinjection water were collected from a sewage treatment station in the Daqing oilfield. Using UV-visible transmission spectra ranging from 190 to 900 nm, three residual neural networks (ResNet) models with different network structures and several layers were constructed for predicting oil content. Comparative analysis was performed using the joint interval partial least squares method (siPLS). Results showed that the mean absolute errors of the three ResNet models were 1.23, 0.76, and 0.29 mg/L, respectively, all demonstrating lower values than those obtained with the siPLS model, notably, increasing the number of layers in the ResNet model enhanced detection accuracy. Consequently, the ResNet model proves to be suitable for predicting oily sewage content within the 20.0 mg/L range as mandated by industry specifications.

Fluorescent dissolved organic matter (FDOM) – particularly tryptophan (Trp), tyrosine (Tyr), and humic acid (HA) – serves as a crucial indicator in environmental monitoring. This study introduced a novel quantitative analysis approach for analyzing three-dimensional excitation-emission matrix spectra (3DEEMs) of FDOM using convolutional neural networks (CNNs). The performance of the CNN model was evaluated and compared with the self-weighting alternating trilinear decomposition (SWATLD) algorithm. Results revealed that the proposed model significantly outperforms the SWATLD algorithm. Specifically, the CNN model achieved R2, RMSE, and MAPE values of 0.964, 0.047, and 14.950%, respectively, while for the SWATLD algorithm, these values were 0.944, 0.062, and 17.439%. Augmentation of the original spectral dataset did not yield a substantial improvement in the performance of the SWATLD algorithm, but it significantly enhanced the prediction ability of the CNN model. This enhancement was evident in the improved R2, RMSE, and MAPE values of 0.989, 0.030, and 12.837%, highlighting the critical role of data augmentation in boosting the performance of the CNN model, especially when dealing with a limited dataset. Application of the CNN model to water samples from Laizhou Bay yielded satisfactory results, enabling a simple and rapid analysis of FDOM in seawater. Therefore, an accurate and convenient analytical model was developed based on EEMs and CNNs, which can swiftly determine the concentration of FDOM in the environment and provide valuable references for environmental monitoring and early warning.

As soil is an important natural resource on the earth’s surface, the composition and characterization of soil have a significant impact on agricultural production, the ecological environment, and human health. Traditional soil identification methods need to deal with a large number of samples and complex chemical analysis, which requires a lot of time and effort. In this paper, a method combining laser-induced breakdown spectroscopy (LIBS) and adaptive particle swarm optimization radial basis neural network (APSO-RBF) is proposed to classify and identify soil standard samples from different geographical regions. By selecting the appropriate principal component of LIBS spectral data as input, the computational complexity can be reduced, the redundancy of the original spectral data can be reduced, and the samples can be classified quickly and accurately. For the soil from 10 different regions, the first 6 principal components with the highest contribution rate in principal component analysis were used as the input of APSO-RBF classification model, and the classification accuracy of the test set could reach 98.81%. In comparison with the back propagation (BP) algorithm, back propagation based on adaptive particle swarm optimization (APSO-RBF) algorithm and radial basis function neural network (RBF) algorithm, the powerful classification performance of the model is verified. The results show that LIBS technology greatly improved the accuracy of soil identification in different regions with the help of APSO-RBF model.

This study presents the eco-friendly synthesis of copper-doped zinc oxide nanoparticles (Cu-ZnO NPs) using Asystasia gangetica leaf extracts as a reducing and stabilizing agent. To reveal their structural, morphological, and optical properties, the synthesized nanoparticles were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, ultraviolet-visible spectroscopy, and energy-dispersive X-ray spectroscopy. The dye degradation efficiency of Cu-ZnO NPs was evaluated for Rhodamine B dye under varying pH, nanoparticle concentration, dye concentration, and reaction time using response surface methodology. Statistical analysis using a central composite design showed that lower nanoparticle concentrations (50 ppm), higher dye concentrations (30 ppt), alkaline pH 9, and extended reaction times (120 min) resulted in optimal dye degradation. The ANOVA results, with a significant F-value and R2 values indicating a good fit, confirmed the model’s adequacy. This green synthesis approach offers a sustainable method for nanoparticle production and its practical application in environmental remediation, particularly in the degradation of synthetic dyes. These findings contribute to the advancement of nanotechnology for eco-friendly applications, with potential implications for wastewater treatment and environmental sustainability.

Sotagliflozin is an oral antidiabetic medication that targets SGLT1 and SGLT2. This medication was not included in any pharmacopeia. The aim of this study was to develop, validate, and compare different methods for measuring the concentration of sotagliflozin in tablet form. These methods include spectrophotometric techniques such as zero-order UV spectrophotometry, first-order derivative spectroscopy, second-order derivative UV spectrophotometry, and high-performance liquid chromatography (HPLC). Method A was a simple zero-order UV spectrophotometric method established for the determination of sotagliflozin in methanol at 254 nm. Method B is a first-order derivative spectrophotometric method, and method C is a second-order derivative spectrophotometric method involving the measurement of amplitudes at 264 and 234 nm, respectively. Method D was performed using HPLC, which was carried out using a C18 column mobile phase consisting of acetonitrile:0.1% orthophosphoric acid (40:60 v/v/v) with a flow rate of 1 mL/min and detection at 249 nm, which provided a sharp peak with a short retention time of 3.748 min. The developed analytical methods were validated statistically. The analysis conducted using liquid chromatography and spectrophotometric methods revealed that both approaches were robust, precise, and accurate, with an RSD of less than 1%. The recovery values were (98–100%) within the typical range. The four analytical techniques were compared statistically, and no significant differences were found. For the quantitative analysis of sotagliflozin, it was discovered that these established procedures are reliable, quick, accurate, and easy to use, and they may also be applied for quality control testing.

The present research work was conducted to show the capabilities of the spectrophotometric approaches comparable to chromatographic techniques in terms of resolution, determination of spectral purity, and quantification of binary mixture present in tablet formulation. Overlapping spectra of the drugs paracetamol (PCM) and flupirtine maleate (FLU) present as a binary mixture were resolved using ratio subtraction plus the extended ratio subtraction method (RS-ERS), ratio subtraction method plus the unified constant subtraction method (RS-UCS) and ratio subtraction method plus the constant multiplication method (RS-CM). After spectral resolution, each drug was quantified by measuring the absorbance at the respective wavelength maximum of the drug using a linear regression equation. The aforementioned three spectrophotometric approaches were initially applied to physical mixtures prepared in the laboratory; later it was extended to analyze marketed tablet formulation. The spectral purity of resolved spectra was studied by computing the spectral contrast angle (SCA) and the spectral ratio factor (SRF). Developed methods were validated as per the parameters mentioned under the International Council for Harmonization (ICH) guideline Q2 (R1). Developed methods were assigned greenness scores using the AGREE tool and successfully used for analyzing marketed tablet formulation.

Raman imaging was used to detect the distribution of each component of wet granulation tablets and analyze their active pharmaceutical ingredient (API) particle size. The four excipients in the tablets – lactose, microcrystalline cellulose, crosslinked sodium carboxymethyl cellulose, and magnesium stearate – were significantly identified by their characteristic peaks, respectively. The average equivalent diameters of API particles in tablets 1, 2, and 3 were 4.49, 6.53, and 13.95 μm, respectively. Tablet 1 exhibited a favorable particle morphology, with minimal differences between particles and an average particle size. The greatest particle size disparities were observed in tablet 3. Furthermore, the cumulative distribution statistics ratio in the API particle system reached 90%, showing that the particle sizes of tablets 1, 2, and 3 were 5.41, 14.45, and 24.00 μm, respectively. This trend was consistent with the API powder results for raw materials measured using a particle size analyzer. The minimum detection limit of the particles was 1.68 μm. In addition, the introduction of the coefficient of variation was used to evaluate the tablets’ uniformity. Whereas tablet 3 exhibited the highest degree of variability and the poorest uniformity, tablet 2 exhibited the lowest degree of variation and the best uniformity. Raman imaging facilitated the visualization of the distribution of each component in the tablet and the API particle size analysis in a “one-stop” manner.

Rapid detection of defects in metal additive manufacturing (AM) components remains a challenge. In this paper, laser-induced breakdown spectroscopy (LIBS) technology was used to establish a rapid identification of metal AM defects and defect-free control groups. The corresponding spectral acquisition of metal AM components with defects and without defects was carried out, and the research elements (Fe, Cr, Mn, and Ti) and corresponding spectral lines were obtained in combination with the NIST database. The spectral lines with features of importance greater than the average value are selected by random forest (RF). The selected spectral lines were used as the input variables of the k-nearest neighbor (KNN) model and the backpropagation neural network (BPNN) model. The classification performance and verification results of KNN, RF-KNN, and RF-BPNN models were compared. The results showed that the RF-BPNN model exhibited the best accuracy, sensitivity, and specificity in the training set, test set and validation set, with accuracies of 99.4, 97.2, and 96.67%, respectively. This indicates that LIBS combined with RF-BPNN can be used for the detection of defects in metal AM components.

A stability-indicating greener UV spectrophotometric method was developed and is here reported to quantify felodipine (FDP) in pharmaceutical and spiked human urine samples, with degradation studies and IR spectral analysis of degradation products. The approach involved the preparation of calibration curves using varying concentrations of FDP in 1:1.5 acetic acid (HOAc) and measuring absorbance at 365 nm. Relative standard deviation (RSD) values for the synthetic mixture were less than 5%, and the recovery rate of FDP ranged from 95.65 to 103.1%. The FDP showed considerable degradation under basic conditions, as indicated by a shift in the λ_max, a decrease in recovery at the analytical wavelength, and changes observed in the IR spectrum. The method's robustness and ruggedness were confirmed through variations in experimental conditions and reproducibility tests, with RSD values between 3 and 5%. In the analysis of spiked human urine samples, the method demonstrated high recovery rates of FDP, ranging from 95.50 to 102.30%, with RSD values below 5%, confirming its applicability to analyse physiological samples. The method showed excellent linearity over 2.5–100 µg/mL FDP, low limits of detection (0.86 µg/mL), and quantification (2.62 µg/mL), with the regression coefficient (r) of 0.9983, making it suitable for routine analysis of FDP in pharmaceutical formulations and clinical samples. This method provides a reliable approach to quantify FDP, with a proven stability-indicating capability, and applies to both pharmaceutical and physiological contexts. The developed method is environmentally friendly, utilizing less toxic reagents like HOAc, minimizing waste and requiring no sophisticated equipment, making it a sustainable option for routine analysis.

Recent innovations in antimicrobial coatings for surgical tools and implants utilize engineered multication oxides combined with nanofibers, nanotubes, and nanosheets, which generate reactive oxygen species to effectively reduce infection risk. This research provides an in-depth examination of lattice dynamics through Raman spectroscopy and ten Raman bands observed from the study indicate the vibrational modes of the orthorhombic structure of V_2–xSb_2xO_5–δ (Sb–V–O, 0.05 ≤ x ≤ 0.08) compounds with the polycrystalline nature of the powder ceramics. The study also assesses the antibacterial properties of Sb–V–O compounds against both human pathogenic gram-positive and gram-negative bacteria. Additionally, the antifungal effectiveness of these compounds is tested against Penicillium spp. and Aspergillus niger. Streptomycin and metronidazole are utilized as positive controls, while dimethyl sulfoxide is used as a negative control. The results highlight the diverse characteristics of the compounds, illustrating their broad-spectrum antimicrobial capabilities and their potential applications in various biomedical and industrial fields.

Аn online in situ detection system based on laser-induced breakdown spectroscopy (LIBS) is developed for the diagnosis and tracing of the rubber combustion process. The feasibility and accuracy of the system are verified by taking styrene-butadiene rubber, fluoro rubber, silicone rubber, chloroprene rubber, and natural rubber as samples. Metallic elements such as Ca, Mg, and Na are detected in the LIBS spectra of rubber combustion. The results show that the smoke produced contains different elements for different kinds of rubbers. Based on the self-developed single particle aerosol mass spectrometry system, the smoke produced by rubber combustion is detected by mass spectrometry. The mass spectrum data are compared and supplemented for LIBS spectral data. Then, the system, combining LIBS with principal component analysis and backpropagation artificial neural network, achieves efficient detection and identification of different rubber smoke, as well as tracking of the rubber combustion process. The identification accuracy reached 94.00%. The combination of LIBS and algorithm helps to improve the efficiency of processing a large amount of spectral information data. Furthermore, the element differences among various types of rubber slabs are analyzed, thereby validating the accuracy of the diagnosis and traceability system. The aforementioned results indicate that the online in situ diagnosis and traceability of the rubber in the combustion process with LIBS is feasible, and using spectral detection for different types of rubber recycling is also promising.

K_2–xSm_xAl₂B₂O₇ (0.0025 ≤ x ≤ 0.04) phosphors were synthesized by a solution combustion method. The X-ray powder diffraction (XRD) method was used to study the phase formation of K₂Al₂B₂O₇. The bond structure of the K₂Al₂B₂O₇ was obtained by using infrared spectrum measurements. In order to investigate the photoluminescence characteristics of the K₂Al₂B₂O₇:Sm³⁺ phosphors, measurements of the excitation and emission spectra were made. The standard 4f-4f electronic transitions of Sm³⁺ were seen in the excitation spectrum at ambient temperature. The emission spectrum of K₂Al₂B₂O₇: Sm³⁺ exhibited four emission peaks corresponding to ⁴G_5/2→⁶H_5/2 (564 nm), ⁴G_5/2→⁶H_7/2 (600 nm), ⁴G_5/2→⁶H_9/2 (646 nm), and ⁴G_5/2→⁶H1_1/2 (706 nm) transitions of Sm³⁺. Lastly, the correlation between emission intensity and Sm³⁺ content was thoroughly investigated.