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The generalized quantum master equation (GQME) approach provides a powerful general-purpose framework for simulating the inherently quantum mechanical dynamics of a subset of electronic reduced density matrix elements of interest in complex molecular systems. Previous studies have found that combining the GQME approach with quasiclassical mapping Hamiltonian (QC/MH) methods can dramatically improve the accuracy of electronic populations obtained via those methods. In this paper, we perform a complimentary study of the advantages offered by the GQME approach for simulating the dynamics of electronic coherences, which play a central role in optical spectroscopy, quantum information science, and quantum technology. To this end, we focus on cases where the electronic coherences predicted for the spin-boson benchmark model by direct application of various QC/MH methods are inaccurate. We find that similar to the case of electronic populations, combining the QC/MH methods with the GQME approach can dramatically improve the accuracy of the electronic coherences obtained via those methods. We also provide a comprehensive analysis of how the performance of GQMEs depends on the choice of projection operator and electronic basis and show that the accuracy and feasibility of the GQME approach can benefit from casting the GQME in terms of the eigen-basis of the observable of interest. [ABSTRACT FROM AUTHOR]

This study presents a proof-of-principle for using optical emission spectroscopy and artificial neural networks for real-time monitoring and control of the operational parameters of a Hall effect thruster: the anode voltage, the anode xenon injection, the discharge current, and the coil current. In that regard, we build an optical database of 26 spectral lines across 6469 operating conditions to train and test the neural network. We then reduced the learning lines from 26 to 15 based on their statistical correlation with the target parameters. After tuning the hyperparameters of the network, the network predicted the thruster's parameters with notable accuracies: 95% for the anode voltage, 84% for the coil current, and 99% for both the anode flow rate and the discharge current. The estimated uncertainty of predictions, at 3 σ , is ± 51 V for voltage, ± 1 A for coil current, ± 0.15 A for discharge current, and ± 0.15 mg s − 1 for anode flow rate. The prediction calculations were within milliseconds and enabled real-time monitoring of the thruster parameters. Therefore, a proportional-integrator-derivative controller (PID) controller was implemented to regulate the anode voltage and flow rate based on the optical emission of the plume. The PID showcased short settling times from 0.1 to 0.4 s and overshoot levels up to 3% of the target value for the voltage and 10% of the target value for the flow rate. These results were for a fixed coil current at 4 A. The study showed that changing the coil current may necessitate more sophisticated prediction models and control strategies. Future work will expand the model's generalizability to different thruster types, propellants, and magnetic field configurations. [ABSTRACT FROM AUTHOR]

Understanding the properties of molecular nitrogen N2 at extreme conditions is the fundamental problem for atomistic theory and the important benchmark for the capabilities of first-principles molecular dynamics (FPMD) methods. In this work, we focus on the connection between the dynamics of ions and electronic excitations in warm dense N2. The restricted open-shell Kohn–Sham method gives us the possibility to reach relevant time and length scales for FPMD modeling of an isolated exciton dynamics in warm dense N2. Wannier localization sheds light on the corresponding mechanisms of covalent bond network rearrangements that stand behind polymerization kinetics. FPMD results suggest a concept of energy transfer from the thermal energy of ions into the internal energy of polymeric structures that form in warm dense N2 at extreme conditions. Our findings agree with the thermobaric conditions for the onset of absorption in the optical spectroscopy study of Jiang et al. [Nat. Commun. 9, 2624 (2018)]. [ABSTRACT FROM AUTHOR]

Carbon nanotubes have shown great promise for high-performance, large-area, solution processable field-effect transistors due to their exceptional charge transport properties. In this study, we utilize the spin-coating method to form networks from selectively sorted semiconducting single-walled carbon nanotubes (s-SWNTs), aiming for scalable electronic device fabrication. The one-dimensional nature of s-SWNTs, however, introduces significant roughness and charge trap sites, hindering charge transport due to the van der Waals gap (∼0.32 nm) between nanotubes. Addressing this, we explored the effects of anion doping on the spin-coated s-SWNT random network, with a focus on the influence of the small size of halogen anions (0.13–0.22 nm) on these electronic properties. Raman and ultraviolet–visible–near-infrared optical spectroscopy results indicate that smaller anions significantly enhance doping effects through strong non-covalent anion–π interactions, improving charge transport and carrier injection efficiency in s-SWNTs, especially for n-type operation. This improvement is inversely proportional to the size of the halogen anions, with the smallest anion (fluorine) effectively transitioning the electrical characteristics of the s-SWNT network from ambipolar to n-type by reducing both junction and contact resistances through anion doping, based on anion–π interaction. [ABSTRACT FROM AUTHOR]

As a threat to meeting the global demand for food created by the continued growth of population, different methods are being applied to enhance seed germination and plant growth. This study investigates the effect of hydrogen-rich water (HRW) and different plasma-activated waters (PAW) and their combinations including HRW, PAW1, PAW2, HPAW1, and HPAW2 on the seed germination of lentils. Different arc discharge reactors are generated under atmospheric pressure in the air. Optical emission spectroscopy was used to detect the radiative species formed in the plasma zone. Raman spectra and physicochemical properties of different waters were investigated. The results demonstrated significant differences in the properties of different activated waters compared to control water. On day 3 after treatment, the fraction and length of germinated seeds were evaluated. During germination, treated water significantly increased germination parameters such as final germination percentage, mean germination time, germination index, and coefficient of germination velocity. HPAW2 exhibited the highest germination index (GI), which combines germination percentage and speed. The plasma systems also effectively reduced the pH of PAW1 and PAW2, with a greater decrease observed in HPAW1 and HPAW1. Analysis of nitrite and nitrate levels revealed that HPAW2 had the highest concentrations, indicating more reactive processes in the presence of hydrogen. Based on our results, it can be concluded that lentil seed germination can be increased using PAW and hydrogenated PAW combined. [ABSTRACT FROM AUTHOR]

Lead halide perovskites (LHPs) have gained prominence for their exceptional photophysical properties, holding promise for applications in high-end optoelectronic devices. However, the presence of lead is one of the major obstacles to the commercialization of LHPs in the field of photovoltaics. To address this, researchers have explored environment friendly lead-free perovskite solar cells by investigating non-toxic perovskite materials. This study explores the enhancement of photophysical properties through chemical engineering, specifically cation exchange, focusing on the crucial photophysical process of hot carrier cooling. Employing femtosecond transient absorption spectroscopy and optical pump terahertz probe spectroscopy, we have probed the carrier relaxation dynamics in A3Sb2I9 with cesium and rubidium cations. This study unravels that the carrier relaxation is found to be slower in Rb3Sb2I9; along with this, the transient mobility decay is found to be retarded. Overall, this study suggests that an antimony-based Rb3Sb2I9 perovskite could be a substantial lead-free perovskite in photovoltaics. These findings provide valuable insights into cation engineering strategies, aiming to improve the overall performance of lead-free-based photovoltaic devices. [ABSTRACT FROM AUTHOR]

Standing striations with a unique pattern have been observed in a radio-frequency-generated hydrogen plasma. The striation pattern consists of a sequence of closely spaced bright ring doublets and two types of dark gaps of different widths. The bright and dark regions in striations were spectroscopically resolved with the Balmer series and the Fulcher band emission lines of hydrogen. Temperatures in these fine structures were determined. In general, the wider dark gap has a higher excitation temperature than the nearby narrower ones in the striation pattern sequence. Bright regions are rotationally hotter than the adjacent dark ones. However, for vibrational temperatures, the trends are not so obvious. No clear pressure dependence of temperatures was observed in striations within the pressure range of maintaining stable standing striations in this work. In addition to optical emission spectroscopy, we used graphite granules as in situ probes for plasma conditions in different striation regions. The striated hydrogen plasma-treated graphite granules were analyzed with Raman spectroscopy. The observed hydrogen-graphite interaction was correlated with the measured temperatures and the fine structures of striations in a discharge tube. [ABSTRACT FROM AUTHOR]

Uniaxial strain has been widely used as a powerful tool for investigating and controlling the properties of quantum materials. However, existing strain techniques have so far mostly been limited to use with bulk crystals. Although recent progress has been made in extending the application of strain to two-dimensional van der Waals (vdW) heterostructures, these techniques have been limited to optical characterization and extremely simple electrical device geometries. Here, we report a piezoelectric-based in situ uniaxial strain technique enabling simultaneous electrical transport and optical spectroscopy characterization of dual-gated vdW heterostructure devices. Critically, our technique remains compatible with vdW heterostructure devices of arbitrary complexity fabricated on conventional silicon/silicon dioxide wafer substrates. We demonstrate a large and continuously tunable strain of up to − 0.15% at millikelvin temperatures, with larger strain values also likely achievable. We quantify the strain transmission from the silicon wafer to the vdW heterostructure, and further demonstrate the ability of strain to modify the electronic properties of twisted bilayer graphene. Our technique provides a highly versatile new method for exploring the effect of uniaxial strain on both the electrical and optical properties of vdW heterostructures and can be easily extended to include additional characterization techniques. [ABSTRACT FROM AUTHOR]

Ultrafast optical spectroscopy is a powerful technique for studying the dynamic processes of molecular systems in condensed phases. However, in molecular systems containing many dye molecules, the spectra can become crowded and difficult to interpret owing to the presence of multiple nonlinear optical contributions. In this work, we theoretically propose time-resolved spectroscopy based on the coincidence counting of two entangled photons generated via parametric down-conversion with a monochromatic laser. We demonstrate that the use of two-photon counting detection of entangled photon pairs enables the selective elimination of the excited-state absorption signal. This selective elimination cannot be realized with classical coherent light. We anticipate that the proposed spectroscopy will help simplify the spectral interpretation of complex molecular and material systems comprising multiple molecules. [ABSTRACT FROM AUTHOR]

The second order cumulant method offers a promising pathway to predicting optical properties in condensed phase systems. It allows for the computation of linear absorption spectra from excitation energy fluctuations sampled along molecular dynamics (MD) trajectories, fully accounting for vibronic effects, direct solute–solvent interactions, and environmental polarization effects. However, the second order cumulant approximation only guarantees accurate line shapes for energy gap fluctuations obeying Gaussian statistics. A third order correction has recently been derived but often yields unphysical spectra or divergent line shapes for moderately non-Gaussian fluctuations due to the neglect of higher order terms in the cumulant expansion. In this work, we develop a corrected cumulant approach, where the collective effect of neglected higher order contributions is approximately accounted for through a dampening factor applied to the third order cumulant term. We show that this dampening factor can be expressed as a function of the skewness and kurtosis of energy gap fluctuations and can be parameterized from a large set of randomly sampled model Hamiltonians for which exact spectral line shapes are known. This approach is shown to systematically remove unphysical contributions in the form of negative absorbances from cumulant spectra in both model Hamiltonians and condensed phase systems sampled from MD and dramatically improves over the second order cumulant method in describing systems exhibiting Duschinsky mode mixing effects. We successfully apply the approach to the coumarin-153 dye in toluene, obtaining excellent agreement with experiment. [ABSTRACT FROM AUTHOR]

Optical emission spectroscopy studies of vanadium plasma in a cathodic-arc discharge in a nitrogen atmosphere have been carried out. Spectral lines of neutral atoms and ions of the cathode material V, V1+, and V2+, and nitrogen N2 and N2+ were observed in the discharge plasma. Analysis and comparison of the intensity of vanadium and nitrogen spectral lines as a function of nitrogen pressure showed that in vacuum excited ions V2+ and V+ are registered, with increasing pressure, the lines V+*, N2*, and N2+* are observed, and at pressures above 0.5 Pa, the neutral vanadium lines are additionally registered. The electron temperature of Te decreases from 5.9 to 3–4 eV with increasing pressure. Studies of cross-sectional scanning electron microscopy images of VN coatings deposited at different nitrogen pressures have shown that a dense, homogeneous, fine-grained microstructure is formed in the coating when the number of neutral V in the plasma is low, while in the presence of a large number of neutrals, the coating structure changes to a dense structure with columnar growth. [ABSTRACT FROM AUTHOR]

The optical spectra of the palladium monosulfide (PdS) molecule in gas phase have been investigated for the first time through laser-induced fluorescence (LIF) and single-vibronic-level (SVL) emission spectroscopies. The I3Σ− − X3Σ− transition system containing 16 vibronic bands was identified in the LIF spectra, covering the energy range of 22 030–23 400 cm−1. The spectra with rotational resolution allowed for the determination of the molecular constants in both the ground X and excited I electronic states, involving the spin–orbit splitting, rotational constant, vibrational frequency, and isotope shift. Isotopically resolved SVL emission spectra permitted the observation of the spin–orbit splitting, vibrational frequency, and vibrational isotope shift of the X3Σ−0+,1 and A3Π2,1,0−,0+ states as they transitioned from the excited I state to the vibrational levels of the X and A states. Ab initio calculations presented plenty of the Λ-S and Ω states of PdS below 28 000 cm−1 and provided strong support for the assignments of the experimental observation. [ABSTRACT FROM AUTHOR]

In pursuit of diamond nanoparticles, a capacitively-coupled radio frequency flow-through plasma reactor was operated with methane-argon gas mixtures. Signatures of the final product obtained microscopically and spectroscopically indicated that the product was an amorphous form of graphite. This result was consistent irrespective of combinations of the macroscopic reactor settings. To explain the observed synthesis output, measurements of C2 and gas properties were carried out by laser-induced fluorescence and optical emission spectroscopy. Strikingly, the results indicated a strong gas temperature gradient of 100 K per mm from the center of the reactor to the wall. Based on additional plasma imaging, a model of hot constricted region (filamentation region) was then formulated. It illustrated that, while the hot constricted region was present, the bulk of the gas was not hot enough to facilitate diamond sp 3 formation: characterized by much lower reaction rates, when compared to sp 2, sp 3 formation kinetics are expected to become exponentially slow. This result was further confirmed by experiments under identical conditions but with a H2/CH4 mixture, where no output material was detected: if graphitic sp 2 formation was expected as the main output material from the methane feedstock, atomic hydrogen would then be expected to etch it away in situ, such that the net production of that sp 2-hybridized solid material is nearly a zero. Finally, the crucial importance of gas heating was corroborated by replacing RF with microwave source whereby facile sp 3 production was attained with H2/CH4 gas mixture. [ABSTRACT FROM AUTHOR]

The document is a contents list from the journal "Analyst" published by The Royal Society of Chemistry, featuring various research papers on topics such as metal surface interactions, cerumen analysis, nano-biosensing platforms, and Raman spectroscopy for leukemia diagnosis. The journal showcases innovative research in the field of chemistry, including advancements in spectroscopy techniques, biosensing platforms, and diagnostic tools. The articles cover a wide range of topics, from nanotechnology to bioanalytical assays, highlighting the diverse and cutting-edge research being conducted in the chemical sciences. [Extracted from the article]

Cationic surfactants are widely used as corrosion inhibitors for industrial tubings and pipelines. They protect the surface of steel pipes through a film-forming mechanism, providing both anodic and cathodic inhibition. To improve the efficiency of the corrosion protection, it is essential to understand the interactions between the surfactants and metal surfaces. To achieve this, surface enhanced Raman spectroscopy (SERS) can serve as a powerful tool due to its surface sensitivity and potential to detect trace amounts of analytes in complex media. In this contribution, we have investigated the behaviour of in situ prepared AgNPs in the presence of benzalkonium chloride as a model corrosion inhibitor using SERS coupled to visible spectroscopy and combined with light scattering methods. By combining these experimental methods, we were able to correlate the aggregation of silver particles with the concentration of added surfactant in the resulting mixture. Using this insight, we also established a SERS method for the detection of benzalkonium chloride traces in water. For this, we utilised the quenching of the SERS response of methylene blue by competitive adsorption of methylene blue and the surfactant on SERS active AgNPs. We believe that our approach can serve a variety of applications to improve the industrial water treatment. For example, the modelling of the interaction of different surfactants with SERS can be used for process intensification, and ultimately, to move towards the digital twinning of corrosion processes for more efficient corrosion inhibition. Furthermore, the ability to adapt our sensing protocol for on-line corrosion inhibitor monitoring allows a fast response to process changes, hence, enabling resource-efficient, continuous process control. [ABSTRACT FROM AUTHOR]

• Six ensemble learning models and two base learner models were established to predict soil heavy metal chromium content. • Ensemble learning models were found to be superior to the single base learner model. • Kennard-Stone algorithm for dividing datasets demonstrates higher predictive accuracy compared to random dividing. • The stacking-2 model obtained the best prediction performance of soil heavy metal chromium content. Soil heavy metal chromium pollution poses significant threats to human health and ecosystems, necessitating accurate quantitative prediction methods for effective monitoring and management. This study aims to develop robust predictive models for soil chromium content in farmland soils of Mojiang Hani Autonomous County, Pu'er City, Yunnan Province, China. These models utilize ensemble learning techniques based on visible and near-infrared spectroscopy. Operations before model building involved partitioning datasets with the Kennard-Stone algorithm to ensure representative training and testing sets. Visible and near-infrared spectroscopy-data preprocessing was performed using Savitzky-Golay smoothing and first-order derivative transformations to enhance signal quality. Bands selection was achieved through the Successive Projections Algorithm (SPA), effectively reducing data dimensionality and collinearity. Six ensemble learning models were constructed and assessed for their predictive performance: Bagging-DTR, Random Forest (RF), Adaboost-DTR, XGBoost-DTR, Stacking-1, and Stacking-2. These models utilized Decision Trees (DTR) and Linear Regression (LR) as base learners. Results demonstrated that ensemble models significantly outperformed individual base learners. Notably, the Stacking-2 model achieved the highest accuracy with an R^2 of 0.954, RMSE of 125.967 mg/kg, and RPD of 4.667. To validate the model's practical applicability, spatial interpolation of soil Cr content was conducted using the Kriging method based on Stacking-2 model predictions. The spatial distribution maps of measured and predicted values exhibited high congruence, underscoring the model's effectiveness in accurately mapping Cr distribution across the study area. This study underscores the efficacy of integrating ensemble learning with visible and near-infrared spectroscopy-data preprocessing and SPA for precise soil heavy metal prediction. The findings offer valuable insights and a scientific basis for enhanced soil quality monitoring, environmental risk assessment, and informed agricultural land management and pollution control. [ABSTRACT FROM AUTHOR]

The TROPOspheric Monitoring Instrument (TROPOMI), onboard the Sentinel-5 Precursor (S5P) satellite launched in October 2017, is dedicated to monitoring the atmospheric composition associated with air quality and climate change. This paper presents the global retrieval of TROPOMI tropospheric formaldehyde (HCHO) and nitrogen dioxide (NO2)vertical columns using an updated version of the Peking University OMI NO2 (POMINO) algorithm, which focuses on improving the calculation of air mass factors (AMFs). The algorithm features explicit corrections for the surface reflectance anisotropy and aerosol optical effects, and uses daily high-resolution (0.25°×0.25°) a priori HCHO and NO2 profiles from the Global Earth Observing System Composition Forecast (GEOS-CF) dataset. For cloud correction, a consistent approach is used for both HCHO and NO2 retrievals, where (1) the cloud fraction is re-calculated at 440 nm using the same ancillary parameters as those used in the NO2 AMF calculation, and (2) the cloud top pressure is taken from the operational FRESCO-S cloud product. The comparison between POMINO and reprocessed (RPRO) operational products in April, July, October 2021 and January 2022 exhibits high spatial agreement, but RPRO tropospheric HCHO and NO2 columns are lower by 10 % to 20 % over polluted regions. Sensitivity tests with POMINO show that the HCHO retrieval differences are mainly caused by different aerosol correction methods (implicit versus explicit), prior information of vertical profile shapes and background corrections; while the NO2 retrieval discrepancies result from different aerosol corrections, surface reflectances and a priori vertical profile shapes as well as their non-linear interactions. With explicit aerosol corrections, the HCHO structural uncertainty due to the cloud correction using different cloud parameters is within ± 20 %, mainly caused by cloud height differences. Validation against ground-based measurements from global Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations and the Pandonia Global Network (PGN) shows that in April, July, October 2021 and January 2022, POMINO retrievals present a comparable day-to-day correlation but a reduced bias compared to the RPRO products (HCHO: R = 0.62, NMB = −30.8 % versus R = 0.68, NMB = −35.0 %; NO2: R = 0.84, NMB = −9.5 % versus R = 0.85, NMB = −19.4 %). An improved agreement of HCHO/NO2 ratio (FNR) with PGN measurements based on POMINO retrievals is also found (R = 0.83, NMB = −18.4 % versus R = 0.82, NMB = −24.1 %). Our POMINO retrieval provides a useful source of information particularly for studies combining HCHO and NO2. [ABSTRACT FROM AUTHOR]

Propulsion performance produced by laser ablation of polymer made of acrylonitrile butadiene styrene is experimentally investigated using the first, second, and third harmonics of a Nd: YAG laser. A ballistic pendulum is employed to assess the impulse and coupling coefficient for laser propulsion application. Fast photography, target ablation, and optical emission spectroscopy are proposed to analyze the energy coupling characteristic. The impulse and coupling coefficient under different pressures are demonstrated to depend on the target ablation and plasma properties which are relevant to laser wavelength. As the laser wavelength decreases, the crater depth and ablation mass are enhanced. Meanwhile, the plasma plume separates at atmospheric pressure and its length extends continuously in the low-pressure range. As a result, plasma including more ejected particles with higher velocity contributes to obtaining excellent impulse and coupling coefficient. In addition, the decreased electron density and temperature indicate higher collision frequency and photoionization dominate rather than inverse bremsstrahlung absorption at shorter laser wavelengths. This work provides a better understanding of the energy conversion mechanism and a reference for improving propulsion performance. [ABSTRACT FROM AUTHOR]

In this work, a simple and highly sensitive fluorescent receptor 1‐(p‐tolyl)‐4,9‐dihydro‐3H‐pyrido[3,4‐b]indole (receptor 1), has been synthesized for the detection of fluoride and cyanide ions. The receptor 1 was very selective towards fluoride and cyanide anions over other anions such as Cl−, Br−, I−, HSO4−, NO3−, HPO42−, and OAc−. Synthesized receptor 1 shows low detection limits 3.29 × 10−8 M for fluoride ion, which was determined by UV–vis absorption. While LOD for cyanide was observed to be 61.5 nM. Importantly, while, receptor 1 produced binding constant for fluoride and cyanide in DMSO‐H2O (1:9, v/v) was found to be 5 × 10−4M−1 and 3.28 × 10−5 M−1, respectively. The variation in the optical and fluorescence spectroscopy confirms the formation of N─H⋯F− and N─H⋯CN− hydrogen bond of the pyrrolic proton The sensing mechanism displayed by receptor 1 for fluoride and cyanide ions was confirmed by 1H‐NMR and FT‐IR spectroscopic along with density functional theory (DFT) calculations. Solution with the fluoride and cyanide ions in DMSO‐H2O (1:9, v/v) shows a color change from light yellow to blue under UV light and yellow to colorless in visible light. [ABSTRACT FROM AUTHOR]

The Environmental Trace Gases Monitoring Instrument (EMI-II) onboard the Chinese GaoFen-5B (GF5B) and DaQi-1 (DQ1) satellites is the successor of the previous EMI onboard the Chinese GaoFen-5 (GF5) satellite, and has a higher spatial resolution and a better signal-to-noise ratio. The GF5B and DQ1 were launched in September 2021 and April 2022, respectively. As part of China's ultraviolet-visible hyperspectral satellite instrument series, the EMI-II aims to conduct network observations of pollution gases globally in the morning and early afternoon. In this study, NO2 data were retrieved from the EMI-II payloads on the GF5B and DQ1 satellites using the Differential Optical Absorption Spectroscopy (DOAS) algorithm. The two satellites were consistently compared, and the results showed strong consistency on various spatial and temporal scales (R2 > 0.8). In four representative regions worldwide, NO2 data from the EMI-II exhibited good spatial consistency with those from the TROPOMI. The correlation coefficient (R2) of the total vertical column density (VCD) between the EMI-II and TROPOMI exceeded 0.85, and that of the tropospheric NO2 VCD exceeded 0.57. Compared with single-satellite observations, the dual-satellite network of the GF5B and DQ1 can effectively increase the observation frequency. On a daily scale, dual-satellite observations can reduce the impact of cloud coverage by 6–8% compared to single-satellite observations, and there are two valid observations of nearly 50% of the world's regions. Additionally, the differences between the two satellites can reflect the NO2 diurnal variations, which demonstrates the potential for studying pollutant gas diurnal variations. [ABSTRACT FROM AUTHOR]

Diamond containing nitrogen‐vacancy centers (NV−) is one of the most investigated materials for quantum technologies, because of this system's exceptional spin properties. Although the NV− optical transition is very bright, it suffers from spectral diffusion and weak zero‐phonon line, and is in the visible range. This limits integration into quantum photonic structures and interfacing with optical fiber networks. In contrast, rare earth (RE) ions exhibit extremely narrow and stable optical transitions, including erbium's 1.5 µm telecom wavelength. Combining RE with NV− properties through short‐range interactions is however challenging as RE do not readily enter the diamond lattice. In this work, a thin‐film‐based architecture in which RE and NV− centers can interact while preserving their unique properties is introduced. Thin films of Er3+:Y2O3 are grown by chemical vapor deposition on diamond substrates with well‐crystallized and highly textured structures. An extensive spectroscopic study of Er3+ transitions at room and low temperatures further reveals that photoluminescence spectra and decays are close to bulk materials. It is also shown that Y2O3 thin film deposition has no detrimental effects on NV− optical and spin properties. RE thin films deposited on diamond can thus be suitable for building hybrid materials for new functionalities in quantum sensing, communication, and processing. [ABSTRACT FROM AUTHOR]

The pH value is an important indicator for determining water quality, and visible near-infrared (Vis-NIR) spectroscopy is an ideal technique for rapid detection. The Vis-NIR spectrum of water is greatly affected by temperature. When using Vis-NIR spectroscopy to detect the pH value of water, temperature interference will affect the prediction accuracy of the water pH value. In this study, several chemometric methods developed in recent years were used to correct the spectra of distilled water samples under temperature interference to improve the prediction accuracy of water pH values. Specifically, this includes the external parameter orthogonalization (EPO) algorithm and the generalized least square weighting (GLSW) algorithm. Spectra of distilled water samples at different temperatures in the 400–1049 nm range were collected, and the correction effects of the EPO algorithm and the GLSW algorithm on the spectra after temperature changes, as well as the prediction errors of water pH values, were tested and examined, compared with traditional full-temperature spectral correction models. The results show that both the EPO algorithm and the GLSW algorithm methods require only a small number of representative samples to obtain filtering matrices. By correcting the spectra of distilled water samples at all temperatures to the reference temperature level, good correction effects can be achieved. Additionally, the prediction accuracy of water pH values of the models corrected by both methods is better than that of the traditional method, and the complexity of the models is also greatly reduced. [ABSTRACT FROM AUTHOR]

Autochthonous dissolved organic matter (Auto-DOM) produced by a biological carbon pump using dissolved inorganic carbon (DIC) from carbonate weathering plays an important role in carbon cycling within inland waters. However, little is known regarding how environmental conditions impact the composition and fate of organic matter, especially in surface waters of the semi-arid Loess Plateau, which is enriched in DIC by significant carbonate weathering. To obtain novel insight, we combined hydrochemistry, isotopic composition (δ2H, δ18O, and δ13C DIC), Rayleigh fractionation model, optical spectroscopy (absorbance and fluorescence), and Fourier transform ion cyclotron resonance mass spectrometry measurements to elucidate how primary production and hydrology impact the composition of DOM and the stability of the resulting Auto-DOM throughout the river–reservoir–wetland aquatic continuum of the Bahe River in the carbonate-mineral-rich semi-arid Loess Plateau where carbonate weathering is significant. The Rayleigh fractionation model results indicated that watershed DIC is primarily consumed through aquatic primary production rather than CO 2 degassing. Further investigation revealed that primary production and evaporation co-occurred in this watershed. With the enrichment of the stable water isotope δ2H, the relative abundances of the allochthonous compounds decreased and the relative abundances of the autochthonous substances increased, suggesting that the terrestrial signal of riverine DOM decreased while autochthonous production increased along the flow pathway. In addition, associations between optical and molecular characteristics among DOM samples from different water bodies revealed that the stability ratio (Fmax(C2/(C2 + C4))) of Auto-DOM to the ratio of carboxylic-rich alicyclic molecules showed a consistent trend, suggesting that phytoplankton-derived and biomineralized C2 compounds are potentially recalcitrant DOM in inland waters. We conclude that hydrology and primary production affect the source, composition, and, potentially, the stability of DOM in DIC-enriched surface waters of the semi-arid Loess Plateau, which may lead to a more humic-like DOM composition in inland water and export this lower bioavailability DOC to the ocean in the long term. [ABSTRACT FROM AUTHOR]

Crystalline Sm3+ substituted V-type hexaferrites Sr 1-x Sm x Fe 8 SnO 15 with composition (x = 0.00, 0.02, 0.06, 0.10) were synthesized using hydrothermal method. With the substitution of Sm3+ ions, the lattice constant 'c' experienced a decrement from 54.4600 Å to 53.0200 Å while the value of lattice constant 'a' firstly increased and then decreased. The crystallite size varied from 37.95 to 50.86 nm. The spherical shape of particles was analyzed by Atomic Force Microscopy (AFM). The VSM analysis revealed that the samples inherent the soft magnetic properties as evidenced by the coercivity value being below 1 k Oe which exemplifies its usefulness in the field of microwave absorption properties. The successive production of heat during hyperthermia analysis indicated the use of this material in cancer cell treatment. The UV visible spectroscopy technique was utilized to investigate many parameter including absorption, Urbach-energy, and band gap. It can be affirmed that the prepared material might be useful for photo-catalytic purposes and hyperthermia applications. [ABSTRACT FROM AUTHOR]

Quetiapine (QTP) is a moderately water-soluble biopharmaceutical classification system (BCS) class II antipsychotic drug used to treat schizophrenia. Carboxymethyl chitosan (CMC) microspheres were prepared using a co-precipitation approach. The Quetiapine was translocated to the brain through a nasal route using carboxymethyl chitosan-calcium carbonate (CMC-CaCO3) hybrid microspheres. During this process, optimization controlled the size of the microspheres by controlling the volume of solution, precipitating agent, and concentration ratios of the precursors. The optimized batch showed a narrow size distribution with high stability in the dispersed phase as characterized by dynamic light scattering. Preliminary characterization revealed crosslinking formation between the carboxymethyl groups of chitosan and the CaCO3 may be responsible for the spherical structure. The preliminary evaluations were done with Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), and UV visible spectroscopy (UV-Vis). The surface morphology was assessed by scanning electron microscopy that showed the microscale range of the spherical-shaped particles. The ex-vivo mucoadhesive studies suggested a high binding affinity toward mucin, having a sustained release effect for up to 8 h. [ABSTRACT FROM AUTHOR]

Fricke gel dosimeters are appropriate candidates for gamma dosimetry. Polyvinyl alcohol Fricke gel dosimeters are the most recent introduced gel dosimeters which have low ion diffusion. In this work, samples of ferrous-xylenol orange-polyvinyl alcohol gel dosimeters were prepared and characterized using optical spectroscopy. Using win XCOM program and the elemental composition of the gel, the mass attenuation coefficients for photons were evaluated. The results exhibited that the prepared gel is the nearly radiological blood-, soft tissue- and water-equivalent. The 60Co gamma cell unit was used to irradiate the gel samples. A dose range response was found linear from 10 to 30 Gy and suitable for blood irradiation dosimetry. Additionally, the gel response good repeatability was confirmed by the coefficient of variation calculations. Furthermore, chemical yield of the gel was estimated to be 34.6. The good characteristics of the prepared gel make it appropriate for dosimetry of blood irradiators. [ABSTRACT FROM AUTHOR]

The etch rate uniformity in photoresist etching was monitored using multi-channel optical emission spectroscopy (OES) and a spatially resolved etch rate model incorporating radical and ion etching characteristics. The F radical densities at various locations were estimated using 8-channel OES and applied to a radical-spontaneous etch rate model to examine the impact of radicals on the etch rate. The ion fluxes were measured using a scanning floating harmonic probe for an ion-enhanced etch rate model to investigate the effect of ions on the etch rate. A combined etch rate model was proposed to explain the effects on both radical and ion etching characteristics, and the etch rates and etch rate uniformities predicted by the model were quantitatively compared with the measured values. The calculated R-squared score (R2) and the mean absolute percentage error (MAPE) of the etch rates predicted by the model were 0.99 and 1.3%, respectively. The etch rate uniformities predicted by the model showed good accuracy with R2 of 0.99 and MAPE of 12.0% compared to the measured values, and the combined etch rate model also successfully predicted the distribution of the etch rate. This study demonstrates that multi-channel OES and the developed model can quantitatively predict the etch rate distribution of plasma etching processes. [ABSTRACT FROM AUTHOR]

ABSTRACT This study presents a green approach for urea synthesis using plasma–ice interaction with N₂ + CO₂ and NH₃ + CO₂ gas mixtures. Plasma characterization via electrical and optical emission spectroscopy revealed that urea formation involves complex reactions driven by high‐energy species, producing reactive nitrogen and carbon intermediates. Plasma‐treated ice exhibited increased pH, electrical conductivity (EC), and reduced oxidation–reduction potential (ORP). Optimization of parameters, especially treatment time, significantly influenced urea formation. The NH₃ + CO₂ plasma produced a higher urea concentration (7.7 mg L−1) compared to the N₂ + CO₂ plasma (0.55 mg L−1) due to ammonia's greater reactivity. This method offers a sustainable, energy‐efficient alternative to traditional urea synthesis processes. [ABSTRACT FROM AUTHOR]

A layered Na2SnO3 with honeycomb structure was synthesized by solid state route using sodium carbonate and tin oxide. The prepared sample was characterized by different physicochemical characterization techniques like X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X‐ray spectroscopy (EDS), X‐ray photoelectron spectroscopy (XPS), ultraviolet visible spectroscopy (UV–vis), photoluminescence spectra (PL), N2 adsorption technique (Brunauer–Emmett–Teller, electrochemical impedance spectroscopy (EIS). The photodegradation of rose bengal dye under UV light was studied. Due to honeycomb structure and high surface area of Na2SnO3, the complete degradation of rose Bengal was observed in 90 min under UV light irradiation. Results of photocatalytic dye degradation reaction demonstrated that Na2SnO3 can be employed as photocatalyst under UV light irradiation. [ABSTRACT FROM AUTHOR]

The present work is involved in synthesizing, characterizing, and evaluating the role of Er3+ ion on structural, optical, and thermal properties of 20CaO–10ZrO 2 –10Y 2 O 3 -30 B 2 O 3 -(30-x)SiO 2 -xEr 2 O 3 (x = 0.3, 0.6, 1.0, and 1.5 mol%) compositions. The as-synthesized samples are characterized by various experimental techniques such as XRD, FTIR, Raman, UV visible spectroscopy, and DSC to study their suitability for optoelectronic applications. The density of glasses increases, whereas the molar volume decreases with the doping of Er 2 O 3 in place of SiO 2. The amorphous nature of the prepared samples is confirmed by the X-ray diffraction pattern. FTIR and Raman spectra confirm the presence of BO 4 and BO 3 structural units in the prepared glass samples. The UV–visible absorption spectra show 4G 9 / 2 , 4G 11 / 2 , 2G 9 / 2 , 4F 5 / 2 , 4F 7 / 2 , 2H 11 / 2 , and 4F 9 / 2 transitions with the Er 2 O 3 doping. The optical band gap increases from 3.25 to 3.61 eV, whereas the refractive index decreases from 2.33 to 2.24 with increasing doping of Er 2 O 3 , except for the SE-1.5 glass sample. The molar refraction decreases with Er 2 O 3 doping. The glass transition temperature increases from 472 to 512 °C with Er 2 O 3 doping in place of SiO 2 , except for the SE-1.5 glass. SE-0.3 glass shows the highest thermal stability, while SE-1.5 glass shows the lowest thermal stability. Therefore, these glasses can be considered for application in optoelectronics. [ABSTRACT FROM AUTHOR]

The present work is involved in the synthesize, characterization and evaluating the role of CuO on physical, structural and optical properties of 45P 2 O 5 -(55-x)Na 2 O-xCuO (x = 0, 1.0, 3.0 and 5.0 mol%) compositions. The as-synthesized samples are characterized by various experimental techniques such as XRD, FTIR, Raman and UV visible spectroscopy to study their suitability for laser and non-linear optical applications. The density of glasses increases whereas molar volume decreases from with the doping of CuO in place of Na 2 O. The amorphous nature of the prepared samples is confirmed by X-ray pattern. FTIR and Raman spectra confirm the presence of metaphosphate (Q2) and orthophosphate (Q0) structural units in the prepared glass samples which confirms that the glass network become more polymerised with the addition of CuO in place of Na 2 O. The optical band gap increases from 1.94 to 4.11 eV whereas refractive index decreases from 2.76 to 2.14 with increasing doping of CuO. The molar refraction decreases while metallization criteria increase with CuO doping. This glass material demonstrates promising potential for applications in non-linear optics. [ABSTRACT FROM AUTHOR]

Weyl semimetal (WSM) states can be achieved by breaking spatial‐inversion symmetry or time reversal symmetry. However, the anisotropy of the energy reduction contributing to the emergence of WSM states has seldom been investigated by experiments. A van der Waals metal MoTe2 exhibits a type‐II WSM phase below the monoclinic‐to‐orthorhombic‐phase‐transition temperature Tc ∼ 250 K. Here, a combined linearly polarized optical‐spectroscopy and electrical‐transport study of MoTe2 is reported at different temperatures. The Drude components in the a‐axis, b‐axis, and c‐axis optical conductivity spectra, together with the metallic out‐of‐plane and in‐plane electrical resistivities, indicate the coherent inter‐layer and in‐plane charge transports. Moreover, the Drude weight in σ1a(ω), rather than the Drude weights in σ1b(ω) and σ1c(ω), decreases dramatically below Tc, which exhibits a highly anisotropic decrease in its Drude weight and thus suggests a strongly anisotropic reduction of the electronic kinetic energy in the WSM phase. Furthermore, below Tc, due to the in‐plane anisotropic spectral‐weight transfer from Drude component to high‐energy region, the in‐plane inter‐band‐absorption anisotropy increases remarkably ≈770 meV, and has the largest value (≈0.68) of normalized linear dichroism among the reported type‐II WSMs. The work sheds light on seeking new WSMs and developing novel photonic devices based on WSMs. [ABSTRACT FROM AUTHOR]

Unlike traditional group‐6 transition metal dichalcogenides (TMDs), group‐10 TMDs such as PtSe2 and PdTe2 possess highly tuneable indirect bandgaps, transitioning from semiconducting in the near‐infrared to semimetal behavior with a number of monolayers (MLs). This opens up the possibility of TMD‐based mid‐infrared and terahertz optoelectronics. Despite this large potential, the optical properties of such materials have shown an extremely large disparity between that predicted and measured. For example, simulations show that a few MLs is required for the semiconductor–semimetal transition, whilst tens of MLs is found experimentally. This is a result of widely used optical extrapolation methods to determine bandgaps, such as the Tauc plot approach, that are not adapted here owing to i) nearby direct transitions, ii) the material dimensionality and iii) large changes in the non‐parabolic bandstructure with MLs. Here, uniquely combining optical ellipsometry to determine the complex permittivity, terahertz time resolved spectroscopy for the complex conductivity and in‐depth density functional theory (DFT) simulations, it is shown that the optical properties and bandstructure can be determined reliably and demonstrate clearly that the semiconductor‐semimetal transition occurs for PtSe2 layers ≈5 MLs. The microscopic origins of the observed transitions and the crucial role of the Coulomb interaction for thin semiconducting layers, and that of interlayer van der Waals forces for multilayer semimetallic samples are also demonstrated. This work of combining complimentary experimental techniques and extensive simulations avoids the application of constrained extrapolation methods to determine the optical properties of group‐10 TMDs, and will be of importance for future mid‐infrared and terahertz applications. [ABSTRACT FROM AUTHOR]

Vertical stratification in marine sediment profiles indicates physical and chemical sedimentary processes and, thus, is the first step in sedimentary research and in studying their relationship with global climate change. Traditional technologies for studying vertical stratification have low efficiency; thus, new technologies are highly needed. Recently, visible and near-infrared spectroscopy (VNIR) has been explored to rapidly determine sediment parameters, such as clay content, particle size, total carbon (TC), total nitrogen (TN), and so on. Here, we explored vertical stratification in a sediment column in the South China Sea using VNIR. The sediment column was 160 cm and divided into 160 samples by 1 cm intervals. All samples were classified into three layers by depth, that is, 0–50 cm (the upper layer), 50–100 cm (the middle layer), and 100–160 cm (the bottom layer). Concentrations of TC and TN in each sample were measured by Elementa Vario EL III. Visible and near-infrared reflectance spectra of each sample were collected by Agilent Cary 5000. A global model and several classification models for vertical stratification in sediments were established by a Support Vector Machine (SVM) after the characteristic spectra were identified using Competitive Adaptive Reweighted Sampling. In the classification models, K-means clustering and Density Peak Clustering (DPC) were employed as the unsupervised clustering algorithms. The results showed that the stratification was successful by VNIR, especially when using the combination of unsupervised clustering and machine learning algorithms. The correct classification rate (CCR) was much higher in the classification models than in the global model. And the classification models had a higher CCR using K-means combined with SVM (94.8%) and using DPC combined with SVM (96.0%). The higher CCR might be derived from the chemical classification. Indeed, similar results were also found in the chemical stratification. This study provided a theoretical basis for the rapid and synchronous measurement of chemical and physical parameters in sediment profiles by VNIR. [ABSTRACT FROM AUTHOR]

In this study, we report the growth and comprehensive spectroscopic analysis of TmF3-doped CaF2 crystals, grown using the vertical Bridgman method. The optical absorption and photoluminescence properties of both trivalent (Tm3+) and divalent (Tm2+) thulium ions were investigated. Optical absorption spectra in the UV-VIS-NIR range reveal characteristic transitions of Tm3+ ions, as well as weaker absorption bands corresponding to Tm2+ ions. The Judd–Ofelt (JO) formalism was applied to determine the intensity parameters Ω2, Ω4, and Ω6, which were used to calculate radiative transition probabilities, branching ratios, and radiative lifetimes for the Tm3+ ions. The emission spectra showed concentration-dependent quenching effects, with significant emissions observed for the concentration of 0.1 mol% TmF3 under excitation at 260 nm and 353 nm for Tm3+ ions and at 305 nm for Tm2+ ions. A new UV emission associated with divalent Thulium is reported. The results indicate that higher TmF3 concentrations lead to increased non-radiative energy transfer, which reduces luminescence efficiency. These findings contribute to the understanding of the optical behavior of Tm-doped fluoride crystals, with implications for their application in laser technologies and radiation dosimetry. [ABSTRACT FROM AUTHOR]

Effective photoinduced charge transfer makes molecular bimetallic assemblies attractive for applications as active light‐induced proton reduction systems. Developing competitive base metal dyads is mandatory for a more sustainable future. However, the electron transfer mechanisms from the photosensitizer to the proton reduction catalyst in base metal dyads remain so far unexplored. A Fe─Co dyad that exhibits photocatalytic H2 production activity is studied using femtosecond X‐ray emission spectroscopy, complemented by ultrafast optical spectroscopy and theoretical time‐dependent DFT calculations, to understand the electronic and structural dynamics after photoexcitation and during the subsequent charge transfer process from the FeII photosensitizer to the cobaloxime catalyst. This novel approach enables the simultaneous measurement of the transient X‐ray emission at the iron and cobalt K‐edges in a two‐color experiment. With this methodology, the excited state dynamics are correlated to the electron transfer processes, and evidence of the Fe→Co electron transfer as an initial step of proton reduction activity is unraveled. [ABSTRACT FROM AUTHOR]

We follow up emission line galaxies identified through the near-infrared slitless HST /WFC3 WISP survey with VLT/FORS2 optical spectroscopy. Over 4 WISP fields, we targeted 85 of 138 line emission objects at |$0.4\lt z\lt 2$| identified in WFC3 spectroscopy. Half the galaxies are fainter than |$H_{AB}=24$|  mag, and would not have been included in many well-known surveys based on broad-band magnitude selection. We confirm 95 per cent of the initial WFC3 grism redshifts in the 38 cases where we detect lines in FORS2 spectroscopy. However, for targets which exhibited a single emission line in WFC3, up to 65 per cent at |$z\lt 1.28$| did not have expected emission lines detected in FORS2 and hence may be spurious (although this false-detection rate improves to 33 per cent using the latest public WISP emission line catalogue). From the Balmer decrement, the extinction of the WISP galaxies is consistent with |$A($| H  |$\alpha)=1$|  mag. From SED fits to multiband photometry including Spitzer |$3.6\, \mu$| m, we find a median stellar mass of |$\log _{10}(M_\star /{\rm M}_{\odot })=8.94$|⁠. Our emission-line-selected galaxies tend to lie above the star-forming main sequence (i.e. higher specific star formation rates). Using [O  iii ], [O  ii ], and H β lines to derive gas-phase metallicities, we find typically sub-solar metallicities, decreasing with redshift. Our WISP galaxies lie below the |$z=0$| mass–metallicity relation, and galaxies with higher star formation rates tend to have lower metallicity. Finally, we find a strong increase with redshift of the H α rest-frame equivalent width in this emission-line selected sample, with higher |$EW_0$| galaxies having larger [O  iii ]/H β and O32 ratios on average, suggesting lower metallicity or higher ionization parameter in these extreme emission line galaxies. [ABSTRACT FROM AUTHOR]

This research offers a comprehensive exploration of the effects of In-doping on the characteristics of CdS nanopowders (NPs). The structural and morphological properties of In-doped CdS nanostructures were investigated, revealing significant changes induced by In-doping. X-ray diffraction (XRD) analysis verified the formation of CdS phase. Determination of crystallite size (D) demonstrated a decrease from 27.0 nm for undoped CdS to 23.0 nm for CdS doped with 12 % In-doped. Field-emission scanning electron microscopy (FESEM) imaging showed grain-like structures with sizes of 20–35 nm, showing variations in particle size distribution with increasing In-dopant concentration. Photoluminescence (PL) analysis illustrated changes in PL intensity and emission peak wavelengths due to In-doping. PL intensity decreased after In-doping. Additionally, a blue-shift in emission peak wavelengths indicated changes in the bandgap energy of CdS induced by In-doping. UV–Vis spectroscopy assessed the optical properties, revealing shifts in absorption and transmission spectra du to In-doping. In-doping enhanced absorption within the 400–500 nm range while decreasing absorption within 600–1000 nm. Transmission spectra displayed increased transparency after In-doping, attributed to modifications in band structure and morphology. Reflectance spectra initially increased with In-dopant concentration within 400–500 nm, followed by a decrease, suggesting alterations in electronic and structural properties. Estimation of band gap energy (E g) unveiled an increase in E g for In-doped CdS nanostructures compared to undoped CdS, likely due to reduced crystallite size and the Burstein-Moss effect induced by In-dopant ions. Raman analysis revealed a shift in peak positions and changes in intensity after In-doping, with a decrease in the 2LO/LO ratio indicating a deterioration in crystalline quality after In-doping. Overall, this comprehensive investigation provides valuable insights into the structural, morphological, optical, and electrical properties of In-doped CdS nanostructures, pivotal for their promising applications in optoelectronic devices and photovoltaics. [ABSTRACT FROM AUTHOR]

The present research article demonstrates the dispersion of boehmite (BHM) nanoparticles into sericin (SER) from silk industry waste with polyvinyl alcohol (PVA) to enhance the optical, mechanical, thermal and electrical characteristics of PVA/SER blend nanocomposites prepared by a simple green synthesis. Techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV visible spectroscopy, field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were carried out for the characterization of the prepared composites. XRD revealed the increased crystallinity of the polymer blend by the reinforcement of BHM. The existence of intermolecular interactions in the blend composite was confirmed by FTIR and UV spectroscopy. The optical bandgap energy of the biopolymer blend decreases with the inclusion of BHM. The SEM and HR-TEM confirmed the homogeneous dispersion of BHM in the blend at 5 wt% loading. The glass transition temperature and thermal stability of the blend nanocomposites were significantly improved by the inclusion of BHM was deduced from DSC and TGA. The dielectric constant and AC conductivity were remarkably increased with the reinforcement of nanoparticles. The activation energy obtained from AC conductivity decreased with temperature. The mechanical properties of the blend nanocomposites (hardness, tensile strength and Young's modulus) were greatly increased in presence of BHM. The 5 wt% sample has the highest tensile strength, Young's modulus, dielectric constant, AC conductivity and optical properties, allowing it to be used to make optoelectronic devices with better charge-storing capacity and flexible-type electrochemical gadgets. [ABSTRACT FROM AUTHOR]

Household cleaning products (HCPs) are widely used; however, their airborne emissions and hazards have not been thoroughly studied. This study is aimed at evaluating the concentrations of volatile organic compounds (VOCs) and metals present in HCPs and the hazards associated with them. A total of 23 VOCs and 19 metals from 75 HCPs (four spray types and 14 intended usage categories) were analyzed using gas chromatography–mass spectrometry and inductively coupled plasma‐mass spectrometry/optical emission spectroscopy. The largest number of VOCs (21 of 23 ingredients) were detected in spray‐type and had the highest frequency (176). d‐Limonene was found in almost all products (69 of 75) and had the highest concentration. Benzene, a carcinogen, was detected in six spray‐type products. Only three of the 23 VOCs—d‐limonene, ethyl acetate, and heptane—appeared in three, one, and one product labels, respectively. Eight of 19 metals were primarily detected in spray‐type and spray foam‐type products, with sodium, magnesium, and calcium as the main components. Nickel, another carcinogen, was detected in both spray‐type and trigger‐type products. Caution is required when using spray‐type products, especially sticker/glue/tar/oil removers containing benzene and nickel. The study discovered that the VOCs and metals varied by their spray type and lacked sufficient harmful information. [ABSTRACT FROM AUTHOR]

We present a detailed model atmosphere analysis of massive white dwarfs with M > 0.9 M ⊙ and T eff ≥ 11,000 K in the Montreal White Dwarf Database 100 pc sample and the Pan-STARRS footprint. We obtained follow-up optical spectroscopy of 109 objects with no previous spectral classification in the literature. Our spectroscopic follow-up is now complete for all 204 objects in the sample. We find 118 normal DA white dwarfs, including 45 massive DAs near the ZZ Ceti instability strip. There are no normal massive DBs: the six DBs in the sample are strongly magnetic and/or rapidly rotating. There are 20 massive DQ white dwarfs in our sample, and all are found in the crystallization sequence. In addition, 66 targets are magnetic (32% of the sample). We use magnetic white dwarf atmosphere models to constrain the field strength and geometry using offset dipole models. We also use magnetism, kinematics, and rotation measurements to constrain the fraction of merger remnant candidates among this population. The merger fraction of this sample increases from 25% for 0.9–1 M ⊙ white dwarfs to 49% for 1.2–1.3 M ⊙. However, this fraction is as high as 78 − 7 + 4 % for 1.1–1.2 M ⊙ white dwarfs. Previous works have demonstrated that 5%–9% of high-mass white dwarfs stop cooling for ∼8 Gyr due to the 22Ne distillation process, which leads to an overdensity of Q-branch stars in the solar neighborhood. We demonstrate that the overabundance of the merger remnant candidates in our sample is likely due to the same process. [ABSTRACT FROM AUTHOR]

Lead halide perovskites (LHPs) are promising for versatile optoelectronic applications due to their tunable bandgap, but their photoinstability impedes the development. Lead iodide (PbI2) inclusions are commonly seen in LHPs, either formed during the fabrication of the thin film or during its degradation under external stimuli like heat and illumination. Here It is shown how the coexistence of these different phases mutually boost their photodegradation. It is demonstrated that the photodecomposition of PbI2 to form I2, and the photo‐induced halide segregation and decomposition of the mixed I─Br perovskite are both accelerated when they are interfaced. Such a mutual destabilization originates from the nature of PbI2, both because it is rich in hole traps whose energy level spreads within the bandgap of perovskite and because it has a loose layered structure. Thus it becomes a sink for both photocarriers (holes) and ions (A‐site cations and halides) transferred from the perovskite, respectively. It is shown that consistently reducing the PbI2 inclusions in the mixed I─Br perovskite thin film improves the solar cell stability substantially, extending, in the model devices, the operational time from ≈10 to 500 h under illumination. [ABSTRACT FROM AUTHOR]

This work aims to investigate a novel structure based on 1‐methylpiperazine cation [Co(NCS)4(OH2)2]·(C5H14N2)·H2O. The novel complex, 1‐methylpiperazine‐1,4‐diium diaquatetrakis (thiocyanato)‐cobalt hydrate, was investigated using DRX, differential thermogravimetry analysis, FTIR, UV–vis, impedance complex analysis, and density functional theory (DFT). Based on the reported results of these characterization tools, the desired complex phases were confirmed. In the title compound, the aromatic ring in the cationic entity adopts a slightly distorted chair conformation, which ensures coordination stability. FTIR analysis were occurred, which supported the presence of surface ligand groups of thiocyanates, and UV–vis spectroscopy of the electronic transition. Explorations of impedance spectroscopy on [Co(NCS)4(OH2)2]·(C5H14N2)·H2O reveal a fascinating electrical behavior which reveals that the Co complex component can be used as an electronic chip and under certain conditions. The electronic structure and optical properties of the complex were explored using the DFT, confirming it as a direct bandgap semiconductor with a predicted bandgap of 2.89 eV. Optical anisotropic features of the complex, aligning with its monoclinic structure, were identified via analysis of the dielectric function across the [100], [010], and [001] crystallographic directions. The thermal analysis was used to confirm the crystal thermal stability. [ABSTRACT FROM AUTHOR]

Amorphous transparent SiCx:H and SiCxNy:H films are prepared at a temperature of 200 °C and a discharge power of 200 W in an inductively coupled RF plasma reactor using hexamethyldisilane vapors and additional argon and/or nitrogen gases. The influence of N2 flow rate on the morphology, chemical structure, elemental composition, transmittance, refractive index, contact angle, and film deposition rate is studied. Plasma components are determined by optical emission spectroscopy. It is shown by HRTEM and EDS mapping methods that the annealed Cu/SiCx:H/Si(100) sample has distinct substrate/film and film/copper layer interfaces, no Cu diffusion occurs, and that the SiCx:H the film can be considered as a promising diffusion barrier layer. Stability of the films during storage under ambient conditions is studied. The tendency of SiCxNy:H films to oxidize is revealed by EDS, IR spectroscopy, and XPS. [ABSTRACT FROM AUTHOR]

During the last decade, thermally activated delayed fluorescence has been the topic of intense research due to its great potential for highly efficient all organic light emitting devices. While the quinazoline heterocycle has been used for its electron withdrawing ability in various push‐pull dyes, quinazoline derivatives have been rarely considered for TADF emitters. Here we design and synthesize a new series of dyes with phenyl‐ or methoxy‐substituted quinazoline rings combined with 9,9‐dimethylacridan, phenoxazine or phenothiazine and either 1,4‐phenylene or 2,5‐thienylene as linker. Combining optical spectroscopy and theoretical investigations, we demonstrate that delayed fluorescence is observed in the solid state for the phenyl‐substituted quinazoline derivatives for which both quasi‐equatorial and quasi‐axial conformations are predicted to coexist. Calculations further suggest that the reversed intersystem crossing is likely to involve the second triplet state that shows small energy splitting with the first singlet state. These results prompt further investigations of phenyl‐substituted quinazoline based dyes for TADF. [ABSTRACT FROM AUTHOR]

Laser-produced plasma coupled with optical emission spectroscopy (OES) is a promising technique for detecting certain isotopes, with unique capabilities such as standoff and rapid detection and minimal to no sample preparation requirements. The key figure-of-merit for isotopic analysis using optical spectroscopy tools is the linewidth relative to the isotope shift. Although the isotopes of hydrogen (1H, 2H, and 3H) possess large isotopic shifts (1H–2H ≈ 180 pm, 1H–3H ≈ 240 pm), being a light element, the H transitions are susceptible to various broadening mechanisms in the plasma environment. One of the critical parameters that influence the linewidth of a transition in an LPP is the incident laser energy. In the present study, we evaluated the role of laser energy on plume expansion dynamics, deuterium emission intensity, and linewidth in a nanosecond laser-produced Zircaloy-4 plasma. The changes in 2Hα emission intensity and linewidth were investigated for varying laser fluence and time after plasma onset. Spatially resolved and spatially integrated OES were performed and compared to investigate the emission spectral features and linewidth of 2Hα. Monochromatic two-dimensional time-resolved imaging was also performed to understand the morphology of the deuterium and protium emission relative to all species in the plume. Our results showed that 1Hα and 2Hα emissions predominantly occur closer to the target. Measurements of 2Hα linewidth approached similar values at later times of plasma evolution regardless of the laser energy. The linewidths of the 2Hα transition showed insignificant differences between spatially resolved and spatially integrated measurements. [ABSTRACT FROM AUTHOR]

The traditional usage of salt taken from vegetables for the treatment of blood pressure and diabetes is seen in several regions of Ethiopia, particularly in Gambella. The aim of the study was to investigate the mineral content, anti‐hypertensive properties, and sensory attributes of salt obtained from the Hygrophilia schulli. The salt was extracted from the ashing of stems of Hygrophilia schulli. Optical Emission Spectroscopy with Inductively Coupled Plasma was used to identify macro‐minerals, micro‐minerals, and some toxic metals. Flame Atomic Absorption Spectroscopy was used to assess the levels of arsenic and mercury. The anti‐hypertensive property of the salt was determined in vivo using the Wistar rats. The extracted salt was rich in potassium and was deficient in sodium from the analyzed macro‐minerals. It was free from mercury, cadmium, chromium, and arsenic. Lead and nickel were below the Tolerable Weekly Intake Provisional specified by the European Union. Among carbonate and sulfate, chloride was the main anion in this salt. The salt was discovered to have a low taste characteristic compared to common salt. However, the taste attribute of the combination of vegetable and common salt in different proportions was better than common salt. Rats fed with salt from Hygrophilia schulli showed a statistically significant lower systolic, diastolic, and mean blood pressure compared to normal‐fed and common salt‐fed rat groups. Generally, this study suggests that Hygrophilia schulli salt has the potential to be a viable alternative to common salt, particularly for those suffering from hypertension and other related chronic conditions. [ABSTRACT FROM AUTHOR]

Background: The present study undertakes the purification of a novel polysaccharide from Tunisian prickly pear (Opuntiaficus-indica (L.) Mill.) rackets (PPPRs) and the determination of its physicochemical properties, structure, antibacterial and antioxidant properties, as well as its in vitro and in vivo wound healing potential. Methods: The PPPR was structurally analyzed by Fourier Transform Infrared Spectroscopy (FTIR) and UV/Visible Spectroscopy, revealing characteristic bands of polysaccharides. According to thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), and Gas Chromatography–Mass Spectrometry (GC–MS) analyses. Results: The crude PPPR is an heteropolysaccharide composed of glucose (62.4%), galactose (19.37%), mannose (10.24%), and rhamnose (7.98%), with an average molecular weight of 90.94 kDa. This novel polysaccharide exhibited notable antioxidant potential assessed by four different in vitro assays: the 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay, ferric reducing power, ferrous chelating activity, and scavenging activity against 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS). In addition, the PPPR displayed high antibacterial activities with a MIC of 2.5 mg/mL against Salmonella Typhimurium and Pseudomonas aeruginosa, cytocompatibility properties, and non-cytotoxicity. Subsequently, the effect of the PPPR on skin wound healing was studied in a diabetic rat model induced by alloxan, revealing a significant acceleration in the wound healing process. This acceleration was evidenced by the expedited recovery of the dermis, increased formation of blood vessels, and enhanced tissue granulation. Conclusion: Therefore, the findings offer fresh perspectives on the creation of a potentially efficient and promising racket polysaccharide-based therapy for the treatment of persistent diabetic wounds. [ABSTRACT FROM AUTHOR]

Bromine monoxide (BrO) is relevant to atmospheric oxidative capacity, affecting the lifetime of greenhouse gases (i.e., methane, dimethylsulfide) and mercury oxidation. However, measurements of BrO radical vertical profiles are rare, and BrO is highly variable. As a result, the few available aircraft observations in different regions of the atmosphere are not easily reconciled. Autonomous multi-axis differential optical absorption spectroscopy (MAX-DOAS) instruments placed at remote mountaintop observatories (MT-DOAS) present a cost-effective alternative to aircraft, with the potential to probe the climate-relevant yet understudied free troposphere more routinely. Here, we describe an innovative full-atmosphere BrO and formaldehyde (HCHO) profile retrieval algorithm using MT-DOAS measurements at Mauna Loa Observatory (MLO – 19.536° N, 155.577° W; 3401 m a.s.l.). The retrieval is based on time-dependent optimal estimation and simultaneously inverts 190 + individual BrO (and formaldehyde, HCHO) SCDs (slant column densities; SCD = dSCD + SCD Ref) from solar stray light spectra measured in the zenith and off-axis geometries at high and low solar zenith angles (92° > SZA > 30°) to derive BrO concentration profiles from 1.9 to 35 km with 7.5 degrees of freedom (DoFs). Two case study days are characterized by the absence (26 April 2017, base case) and presence of a Rossby-wave-breaking double tropopause (29 April 2017, RW-DT case). Stratospheric-BrO vertical columns are nearly identical on both days (VCD = (1.5 ± 0.2) × 10 13 molec. cm -2), and the stratospheric-BrO profile peaks at a lower altitude during the RW-DT (1.6–2.0 DoFs). Tropospheric-BrO VCDs increase from (0.70 ± 0.14) × 10 13 molec. cm -2 (base case) to (1.00 ± 0.14) × 10 13 molec. cm -2 (RW-DT) owing to a 3-fold increase in BrO in the upper troposphere (1.7–1.9 DoFs). BrO at MLO increases from (0.23 ± 0.03) pptv (base case) to (0.46 ± 0.03) pptv (RW-DT) and is characterized by an added time resolution (∼ 3.8 DoFs). Up to (0.9 ± 0.1) pptv BrO is observed above MLO in the lower free troposphere in the absence of the double tropopause. We validate the retrieval using aircraft BrO profiles and in situ HCHO measurements aboard the NSF/NCAR GV aircraft above MLO (11 January 2014) that establish BrO peaks around 2.4 pptv above 13 km in the upper troposphere–lower stratosphere (UTLS) during a similar RW-DT event (0.83 × 10 13 molec. cm 2 tropospheric-BrO VCD above 2 km). The tropospheric-BrO profile measured using MT-DOAS (RW-DT case) and using the aircraft agree well (after averaging-kernel smoothing). Furthermore, these tropospheric-BrO profiles over the central Pacific Ocean are found to closely resemble those over the eastern Pacific Ocean (2–14 km) and are in contrast to those over the western Pacific Ocean, where a C-shaped tropospheric-BrO profile shape has been observed. [ABSTRACT FROM AUTHOR]

Preparation conditions play a key role in tailoring the properties of ceramic materials, including ferrite, to suit efficient industrial and technological applications. This manuscript is concerned with correlating the structural, spectroscopic, optical, transport, and dielectric properties of nickel zinc ferrite nanoparticles (NZNs) to the sintering temperature as an effective preparation condition controlled through the coprecipitation technique. Techniques for studying the various features of the synthesized compounds include x-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, and the LCR bridge. XRD data showed the as-prepared samples' single-phase inverse spinel structure and an increase in crystallinity with increasing sintering temperature. SEM images show the nanosized range with semi-spherical particles for all the NZN fabricated samples. Moreover, Raman spectroscopy results showed that the four distinct active modes (Eg, F2g(2), A1g(2), and A1g(1)) for the NZN compounds have the same lattice strain tendency. The direct and indirect optical energy gap values (2-3.82) eV of the synthesized compounds span a wide range in the visible and ultraviolet spectrum, making them candidates for optoelectronic applications. In general, sintering temperature plays an outstanding role in increasing the values of some features such as crystallite size, optical energy gap, and electrical conductivity, and correspondingly decreasing other features such as unit cell volume dissociation density, absorption bands, and dielectric parameters. [ABSTRACT FROM AUTHOR]