Search

• 27-day variations of GCR flux according to measurements of AMS-02 and others. • Parameterization of the amplitude-energy spectrum of variations. • Consequences of the force-field model for short-term modulation. This work presents the results of the analysis of 27-day variations in the flux of galactic protons registered by STEREO, SOHO, and AMS-02 in 2015–2016. We calculate variations' amplitude using several different approaches and propose a description of its energy dependence in the range of magnetic rigidity from approximately 0.3 to 100 GV. We also analyse variations of the solar modulation potential, which is the only parameter of force-field model, and consider the possibility of describing the 27-day variations of galactic cosmic rays within the framework of this model. It is shown that rigidity dependence of the 27-day variations amplitude cannot be properly described using this simple approximation. [ABSTRACT FROM AUTHOR]

• Automatic selection of embedding dimension in Singular spectrum analysis is achieved. • Singular spectrum analysis yields the most stable and accurate sea level heights among the methods. • Singular spectrum analysis provides a better concentration of spectral power in the periodogram. In order to obtain reliable GNSS-R derived sea level heights (SLHs), it is crucial to extract accurate reflected signals from signal-to-noise ratio (SNR) data. In this study, Quadratic Fitting, Empirical Mode Decomposition (EMD), Ensemble Empirical Mode Decomposition (EEMD), and Singular Spectrum Analysis (SSA) are adopted for extracting the reflected signals from SNR data, which are then analyzed with Lomb Scargle Periodogram (LSP) assisted with tidal harmonic analysis for GNSS-R SLHs. Three continuous GNSS stations including Onsala in Sweden, Friday Harbor in the United States, and Brest in France with tidal ranges of approximately 1 m, 3 m, and 7 m, respectively, were used in the study. The derived SLHs were evaluated against the nearby or co-located tide gauge records. The results reveal that the three proposed algorithms effectively cope with the multi-peaks spectrum problems when using the conventional Quadratic Fitting without a priori reflected height constraint, and SSA can provide the solutions with fewer outliers among the proposed methods with the RMSEs of 6.7 cm, 13.4 cm and 39.6 cm at Onsala, Friday Harbor, and Brest stations, respectively. Without implementing tidal harmonic analysis, SSA is the method capable of acquiring reliable SLHs among the stations, as evidenced by comparing with co-located gauge records, particularly at the Brest station. In summary, SSA not only distinguishes signals across different frequencies, but also orders the signal components according to their eigenvalues, demonstrating the potential to extract the reflected signals from SNR and enhance the stability and accuracy of GNSS-R applications. [ABSTRACT FROM AUTHOR]

• Analysis of geomagnetic field's H time series during quiet geomagnetic condition. • The H time series from high latitude region shows anti-persistent behaviour. • H time series of quiet geomagnetic condition shows multifractal characteristics. • Change in multifractal characteristics with latitude is observed. • The cause of multifractality is identified as long-range correlations. The generation of geomagnetic time series frequently involves intricate spatio-temporal dynamics, wherein nonlinearity and scaling emerge as pivotal mechanisms. The present work investigates the fractal properties of geomagnetic field, and its sources during quiet geomagnetic conditions, by analyzing the horizontal component data of 1 min resolution (H time series) from different latitude regions. Analysis using Auto Correlation Function (ACF), Power spectrum analysis (PSA), Rescaled range analysis (R/S) and Detrended Fluctuation Analysis (DFA) gave indications of the presence of long-range correlations, fractal properties and scaling behaviour of quiet period H time series data. The strong q dependence of generalized Hurst exponent h(q) and scaling exponent Ʈ(q), obtained from the Multifractal Detrended Fluctuation Analysis (MFDFA) method, confirmed the multifractal behaviour of quiet period H time series. The multifractal source analysis of the quiet period H time series with its shuffled and surrogate time series data revealed that, the multifractal characteristics are caused almost entirely by the long-range correlations between small and large fluctuations. The analysis of the latitudinal variations in the multifractal characteristics is also performed as a part of the work, by considering H time series belonging to various latitudes under almost same longitude. The observed decrease in the generalized Hurst exponent values with increase in latitude indicates the change in the multifractal characteristics of the time series with latitude. Also the work revealed that, the H time series from high latitude region shows anti-persistent behaviour, even when the H time series from observatories located at the low and mid latitude regions exhibiting persistent behaviour. The change in the persistence, anti-persistence behaviour can be related to the strength of Earth's magnetic field. [ABSTRACT FROM AUTHOR]

This study successfully synthesized novel phosphors Ca 2 GaTaO 6 : x Dy3+ (CGTO: x Dy3+) and Ca 2 GaTaO 6 :0.06Dy3+, y Sm3+ (CGTO:0.06Dy3+, y Sm3+) using the high temperature solid-phase reaction preparation. The microstructure, optical properties, and energy transfer mechanism of the phosphors were studied through X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence (PL) spectra and fluorescence lifetimes. XRD and corresponding refinement results indicate that Dy3+ and Sm3+ ions were effectively doped into the Ca 2 GaTaO 6 (CGTO) lattice. The SEM graphs show that the elements in CGTO:0.06Dy3+, 0.5Sm3+ phosphors are uniformly distributed. PL spectra analysis show the CGTO: x Dy3+ phosphors display two strong emission peaks located at 482 nm for blue emission and 575 nm for yellow emission when excited with 350 nm light. Under uniform conditions, when excited with 365 nm of light, the CGTO:0.06Dy3+, y Sm3+ phosphors emit light that can be tuned with adjustable color coordinates and correlated color temperature (CCT) by incorporating varying proportions of Sm3+ ions. This tunability is achieved through the effective energy migration from Dy3+ to Sm3+ ions within the phosphor material. Furthermore, the emission spectra and weaken lifetimes of the CGTO:0.06Dy3+, y Sm3+ confirm the energy transport between Dy3+ and Sm3+, and the energy transfer efficiency reached to 76 %. At 423 K, the luminescence intensity of CGTO:0.06Dy3+, 0.05Sm3+ phosphor retains 87 % of the intensity observed at 298 K, signifying its excellent thermal durability. Finally, the electroluminescent performance of the CGTO:0.06Dy3+ and CGTO:0.06Dy3+, 0.05Sm3+ phosphors packaged on 365 nm light-emitting diode (LED) chips respectively were studied to investigate the capability applications of the phosphors in white light-emitting diodes (WLEDs) field. The CCT of the packaged LEDs decline from 3396 to 2825 K, indicating CGTO:0.06Dy3+, 0.05Sm3+ phosphor shifts to warmer white light. At a voltage input of 3.4 V and a current of 600 mA, the thermal sensing shows that the WLEDs maintain aptitude for 90 min, showing that the packaged WLEDs can function consistently under elevated temperatures. These studies indicated the phosphors have potential applications in indoor lighting. [ABSTRACT FROM AUTHOR]

Southeastern Turkey perished by the M w 7.8, Kahramanmaras earthquake on February 6, 2023, at 01:17 UT (04:17 LT). The Kahramanmaras-centered event, hit by the break of the East Anatolian Fault Line, is felt in Syria, Egypt, Lebanon, Iraq, and Cyprus on the border of Turkey. Together with Syria, it causes loss of lives and severe damage in 10 cities. This work is dedicated to the people of the region. The study discusses the causality of anomalies by conducting ionospheric anomaly research via the interpolated TEC map obtained from the CODE according to the coordinates of the epicenter of the earthquake (latitude, longitude). The TEC amplitudes are observed by evolving the time-domain TEC map into the frequency-domain with the Fourier transform. The peaks of the amplitudes allow preliminary information for the anomaly days. For the anomaly, the TEC (TECU) boundaries are drawn by the statistical specification. The TEC map outside these boundaries is marked as an anomaly. The causality of abnormalities is tried to be read through the triad of the geomagnetic storm(s) , solar activity , and the earthquake effect. One can find seven anomaly days in the paper. January 30, February 2, 3, 11, 15, 16, and 21 are the anomaly days. The essay probably detects the anomaly before 3 days related to the Southeastern earthquake. • Reads the causality of the earthquake in southeast Turkey (Mw 7.8), through the ionosphere-earth crust relationship. • Notices potential anomalies by presenting the time-domain TEC atlas in the frequency domain with Fourier spectral analysis. • Considering all possible TEC anomaly essentials detect the precursors of the earthquake 3 days before the event day. [ABSTRACT FROM AUTHOR]

Studying the mechanisms of bagasse conversion into syngas is essential to sustain the growing use of biomass in energy economy production. In this work, the precise kinetics of bagasse gasification with various gasification agents was firstly investigated employing in-situ infrared spectra with Coats-Redfern integration, combining qualitative infrared spectroscopy allowed for kinetic analysis, so as to explore how the intermediate species vary in each basic reaction. The results demonstrate that the CO 2 agent reduces the activation energy of nitryl after amino oxidation, making the lignin involved in gasification more easily as well as causing higher gasification efficiency. On the one hand, steam serving as a gasification agent enhances the concentration of hydroxyl groups and produces H 2 -rich syngas. On the other hand, the strong oxidizing hydroxyl group reduces the energy barrier of carbonyl and carboxyl groups in cellulose, which facilitates the gasification process. Furthermore, this study compared the effects of gasification agent (H 2 O or CO 2) on syngas composition, reactor temperature distribution, carbon conversion rate, gasification efficiency, as well as low calorific value, providing essential information for understanding the micro-reaction pathways and pathway regulation during bagasse gasification. • Reducing the activation energy of functional groups are regulated by gasifiers. • The synergistic of gasification agents regulate chemical bond-breaking pathways. • The prospects of producing H 2 from biomass gasification are elucidated. [ABSTRACT FROM AUTHOR]

Software-Defined Radios are radio communications devices that have been growing and developing on a larger scale in recent years. Communications are intrinsically embedded in our day by day, thus presenting a higher motivation to use software-defined radios due to its attractive cost. However they present technical limitations. This paper addresses this problem, which is the non-linearity behaviour of gain and frequency in the LimeSDR-USB. That is, this equipment is used to produce a FM signal with an associated frequency and gain before being parameterised according to the internal parameters of each software-defined radio. Each software-defined radio presents a value of frequency and gain of its own, which correlates to the generated signals at the output level. To avoid this, machine learning networks were used, in which networks were trained to adapt to the non-linearity of these devices and correct it without the user noticing. This way, the user sets a desired frequency and gain in a signal, at the output of the software-defined radios, and a neural network calculates which values the software-defined radios should be parameterised, thus mitigating the non-linearity behaviour. This paper presents the evaluation of a laboratory prototype based on low-cost commercial software-defined radios equipment, to replace an expensive metrologically calibrated equipment used for radio frequency tests on a new concept of industrial test station, with description of the integration of Digital Twins, with their physical and virtual parts. [ABSTRACT FROM AUTHOR]

In the automotive industry, products must be tested and verified before being launched; currently, products such as automotive radio are usually tested with expensive metrology equipment, such as the Rohde & Schwarz SFE100, which produces radio frequency signals. This study assessed the feasibility of replacing the SFE100 with two inexpensive devices, Adalm-Pluto and LimeSDR usb, which are software-defined radios. For this evaluation, a study was carried out to determine specific metrological characteristics and then to compare with those of metrological equipment. Based on the results and tests of the study, we conclude that SDRs can generate test signals (FM, DAB, DVB, ISDB and SXM) with uncertainties of 0.5dBm and a spectral density ratio comparable to SFE100, thereby enabling their replacement. Furthermore, the evaluation datasets of all equipment have been publicly available [1] , enabling the scientific community to extract the metrological uncertainties for all signal carriers generated by the device. The result of this study proposes a methodology for testing auto radios that is innovative and can be applied to a production line based on the principles of Industry 4.0. [ABSTRACT FROM AUTHOR]

A series of Bi 2 Sr 2- x Ni x CaCu 2 O 8+ δ (x = 0.00, 0.10, 0.20 and 0.30) ceramics samples were synthesized by Pechini sol-gel method. In this work, the microstructure and structure stability of Ni-doped Bi2212 system were investigated particularly by X-ray diffraction, electron microscopy and high-pressure Raman spectroscopy. It is confirmed that the main phase of all samples is the typical Bi2212 tetragonal phase with space group I 4/ mmm. As Ni-doping amount x ≤ 0.20, the number of Ni atoms entering the Bi2212 lattice increases gradually with increasing x. These Ni atoms preferentially occupy Sr-sites, resulting in a gradual increase in the a and c axis lengths of Bi2212 structure. The formation of containing-Ni Bi2212 lattice is mainly derived from the insertion of sufficient Ni–O two-dimensional (2D) monomers. Contrarily, when x > 0.20, these Ni–O 2D monomers will preferentially form the NiO particle and the chance of Ni atoms entering the Bi2212 lattice is reduced, which leads to a shrinkage of Bi2212 lattice parameters. Besides, under high-pressure (0–20 GPa) condition, Raman spectrum analysis shows that the O Sr peak significantly shifts to the higher wavenumber and Bi2212 phase could still maintain the tetragonal structure, suggesting that it has a relatively high structure stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • PE and PP MPs restrain pyrolysis characteristic of DS, while PVC MPs activates it. • MPs restrains the output of gas products but improved the combustible proportion. • PVC MPs improves the aromaticity, stability and adsorption activity of SS biochar. The concentration of microplastics (MPs) in sewage sludge (SS) ranged from 1600 to 56400 particles per kilogram of dried SS (MPs: dried SS = 0.14–5.09), so its effect on SS pyrolysis performance should not be negligible. This study attempted to investigate the effect of typical MPs, including polypropylene (PP), polyethylene (PE), and polyvinyl chloride (PVC), on the pyrolysis performance (pyrolysis characteristics and major gaseous product evolution) of SS and their biochar characteristics via thermogravimetry-mass spectrometry (TG-MS) and physicochemical property analysis of biochar. The results showed that the PVC MPs enhanced the pyrolysis of SS, while the PP and PE MPs had an inhibitory effect. The total amounts of gas products tended to decrease with all MPs addition. However, the proportions of combustible components (H 2 , CH 4 , and C 2 H 2) increased. Among the biochar products, the presence of PVC MPs during the pyrolysis of SS resulted in a more porous, stable and aromatic biochar. [ABSTRACT FROM AUTHOR]

This study reports the successful synthesis and comprehensive characterization of ZrO 2 :Dy3+ phosphors with the incorporation of K+ ions. The introduction of Dy3+ and K+ in the ZrO 2 lattice as lanthanide activators demonstrates its potential as an efficient host material. The structural integrity of ZrO 2 remains unaltered following the doping process. Fourier-transform infrared spectroscopy (FTIR) analysis confirms the presence of Zr-O and O-H stretching, along with H 2 O bending modes in the phosphor sample. The wide luminescence band seen at 460 nm is attributed to luminescence defects in the ZrO 2 induced by oxygen, and the presence of water molecules. Photoluminescence (PL) spectra analysis reveals pronounced emission peaks at 491 and 578 nm, corresponding to 4F 9/2 → 6H 15/2 and 4F 9/2 → 6H 13/2 transitions, respectively, upon excitation at 349 nm. Optimizing the Dy3+ doping concentration to 0.4 wt% and achieving a critical distance of 31.82 Å resulted in efficient energy transfer. Notably, co-doping K+ as a charge compensator significantly enhances the luminescence intensity. Moreover, at lower temperatures, direct excitation of Dy3+ ions through our pump wavelength, coupled with exciton-mediated energy transfer, leads to a remarkable increase in PL intensity. Tailoring the doping concentrations effectively shifts the emission spectrum of the phosphor mixture, aligning with the standard white light illumination coordinates (0.333, 0.333). This property positions the material as a promising candidate for applications in white light-emitting diodes (WLEDs) and various high-quality lighting applications. The enhanced photoluminescence and temperature dependence observed in ZrO 2 :Dy3+ phosphors upon the incorporation of K+ ions pave the way for their potential utilization in advanced luminescent devices. [ABSTRACT FROM AUTHOR]

During the process of developing commercial chips, the phosphors with single broadband emission are indispensable. In this report, a new ternary phosphate phosphor Na 3 Ba 2 Ca(PO 4) 3 :Eu2+ has been successfully synthesized by the high-temperature solid-state reaction (HSSR) method, which shows broad emitting band in the range of 350–600 nm centered at 436 nm (FWHM ∼ 72.3 nm). The crystal structure of the Na 3 Ba 2 Ca(PO 4) 3 and Eu2+ doped Na 3 Ba 2 Ca(PO 4) 3 were determined by the Rietveld method, indicating the trigonal system with P 31 c space group. The selective two-site occupancy tendency of Eu2+ ions at Ba1O 9 and Ca2O 8 sites in the matrix was comprehensively revealed according to the split peaks (433 nm and 469 nm) at 298 K and 11 K, computational validation and fluorescence lifetime analysis of photoluminescence spectrum. Impressively, the optimal Na 3 Ba 2 Ca(PO 4) 3 :0.02Eu2+ phosphor exhibits appropriate spectrum resemblance (SR) indexes (58.5% and 72.2%), proper thermostability (78.6%) and excellent chromaticity stability (Δ x = 8.68 × 10−6 and Δ y = 3.64 × 10−5). Besides, the phosphor prepared by HSSR owns the higher internal quantum efficiency of 62.1% in comparison with that synthesized by polymerizable complex (PC) method. The new phosphor can serve as a potential broadband and blue-emitting phosphor for the application of solid-state lighting and plant growth. [Display omitted] • First synthesis of Eu2+ ion doped Na 3 Ba 2 Ca(PO 4) 3 phosphor by high temperature solid phase method. • The internal quantum efficiency of phosphor prepared in this work is 9 times of polymerizable complex (PC) method. • Two site-occupancy of Eu2+ in host was carefully determined. • The Na 3 Ba 2 Ca(PO 4) 3 : 0.02Eu2+ owns good thermostability and chromaticity stability. [ABSTRACT FROM AUTHOR]

Upconversion nanoparticles have emerged as promising materials for non-contact temperature sensors due to their unique detection capabilities and low interference, so it is valuable to explore simple and effective approaches to enhance the temperature measurement sensitivity. In this study, we employed a special sol-gel method to prepare NaGd(MoO 4) 2 powder by calcining the precursor mixture, and the fluorescence properties as well as thermal sensitivity were investigated. Analysis based on XRD, SEM and energy transfer modes revealed that the enhancement in temperature sensitivity resulted from the increased distance between the sensitizer and activator ions as well as changes in crystallinity, compared with normal sol-gel method. By optimizing the doping of rare earth ions, the highest sensitivity reached 3.34 %K−1. Additionally, fluorescence spectra analysis of NaGd(MoO 4) 2 samples synthesized via different methods demonstrated that energy transfer between the sensitizer and activator ions can be achieved through high-temperature calcination. Moreover, LiGd(MoO 4) 2 samples prepared using the unique sol-gel method exhibited similar enhancements in temperature sensitivity as NaGd(MoO 4) 2 powder. These findings imply that the samples prepared through the unique sol-gel synthesis method exhibit significant potential in terms of their fluorescence and temperature detection capabilities. [Display omitted] • NaGd(MoO 4) 2 :Er3+-Yb3+ sample was prepared by a special sol-gel method which were calcined after precursor mixing. • The method of calcining after precursor mixing increases the distance between ions and affects crystallinity. • The mixing ratio of the Er3+-Yb3+ doped precursor can be adjusted to achieve higher upconversion. • The temperature sensitivity of the special sol-gel sample prepared in the manuscript is higher, reaching 3.34 %K−1. • Er3+/Yb3+ doped LiGd(MoO 4) 2 prepared by the special sol-gel method also showed similar enhancement in temperature sensitivity. [ABSTRACT FROM AUTHOR]

Ba 0.5 Sr 0.5 TiO 3 –ZnAl 2 O 4 composite ceramics were prepared by double sintering and conventional sintering. The results show that the double sintering can effectively reduce the ion diffusion between Ba 0.5 Sr 0.5 TiO 3 and ZnAl 2 O 4 phases. The double sintered samples exhibit higher density and more uniform grain size distribution than the conventional sintered samples. The dielectric permittivity of double sintered samples is lower than that of conventional sintered samples. Impedance spectrum analysis shows that the oxygen vacancy content and grain boundary resistance of the double sintered samples is lower than that of the conventional sintered samples, which indicates that the Q value of the double sintered samples is higher than that of the conventional sintered samples. The optimum dielectric tunability and Q value of double sintered 60 wt%Ba 0.5 Sr 0.5 TiO 3 -40 wt%ZnAl 2 O 4 sample are 23.4% at 30 kV/cm and 276 at 2.257 GHz, respectively. Therefore, double sintering is a strategy that can effectively adjust the dielectric tunability and Q value of BST-ZA composite ceramics. [ABSTRACT FROM AUTHOR]

The precise classification of land covers with hyperspectral imagery (HSI) is a major research-focused topic in remote sensing, especially using unmanned aerial vehicle (UAV) systems as the abundant data sources have brought severe intra-class spectral variability and high spatial heterogeneity challenges, making precise classification difficult. To this end, a novel three-dimensional singular spectrum analysis (3DSSA) method is proposed for the 3D feature extraction of HSI. It aims to construct a low-rank trajectory tensor containing global and local features and extract both spectral discrimination features and spatial contextual features in conjunction with tensor singular value decomposition (t-SVD). To reduce the risk of tensor operations exceeding memory on large-scale HSI data, the extended regional clustering (RC) 3DSSA framework (RC-3DSSA) is proposed for precise HSI classification. RC-3DSSA uses RC processing to alleviate the scale diversity and further applies 3DSSA to tackle issues of intra-class spectral variability and spatial heterogeneity. In order to effectively evaluate the performance of RC-3DSSA, a new challenging classification dataset namely the Qingdao UAV-borne HSI (QUH) dataset was further built. It consists of three sub-datasets: QUH-Tangdaowan, QUH-Qingyun, and QUH-Pingan, which are freely available as benchmarks for precise land cover classification. The experimental results on QUH and two publicly available datasets show that the RC-3DSSA can accurately distinguish ground objects and reliably map their distribution when benchmarked with ten state-of-the-art methods. Specifically, the overall accuracies achieved are 86.62%, 87.51%, and 87.35% under 10% spatially disjoint training samples for the three UAV-borne HSI datasets, respectively, providing the best performance. [ABSTRACT FROM AUTHOR]

Amyloidosis is a deleterious condition caused by abnormal amyloid fibril build-up in living tissues. To date, 42 proteins that are linked to amyloid fibrils have been discovered. Amyloid fibril structure variation can affect the severity, progression rate, or clinical symptoms of amyloidosis. Since amyloid fibril build-up is the primary pathological basis for various neurodegenerative illnesses, characterization of these deadly proteins, particularly utilising optical techniques have been a focus. Spectroscopy techniques provide significant non-invasive platforms for the investigation of the structure and conformation of amyloid fibrils, offering a wide spectrum of analyses ranging from nanometric to micrometric size scales. Even though this area of study has been intensively explored, there still remain aspects of amyloid fibrillization that are not fully known, a matter hindering progress in treating and curing amyloidosis. This review aims to provide recent updates and comprehensive information on optical techniques for metabolic and proteomic characterization of β-pleated amyloid fibrils found in human tissue with thorough literature analysis of publications. Raman spectroscopy and SAXS are well established experimental methods for study of structural properties of biomaterials. With suitable models, they offer extended information for valid proteomic analysis under physiologically relevant conditions. This review points to evidence that despite limitations, these techniques are able to provide for the necessary output and proteomics indication in order to extrapolate the aetiology of amyloid fibrils for reliable diagnostic purposes. Our metabolic database may also contribute to elucidating the nature and function of the amyloid proteome in development and clearance of amyloid diseases. [ABSTRACT FROM AUTHOR]

An accurate carbon price prediction is vital for governments to formulate emission reduction policies and for corporate managers to carry out sustainable management. Although many models have been proposed to meet this purpose, there is still a lack of comprehensive comparisons among the key competing models in a single study. This study conducted a comprehensive evaluation of six feature selection methods and six machine learning models for carbon price prediction, and then proposed a novel data-driven hybrid model that integrates singular spectrum analysis, random forest, and long short-term memory neural network. The results show that random forest and long short-term memory neural networks are the most competitive feature selection and prediction models, respectively. It is more reasonable to construct the model's input by comprehensively considering variables' short-, medium-, and long-term features. When the recombination value is approximately half the length of the embedding window, the singular spectrum analysis is most conducive to improving the prediction accuracy. The hybrid model proposed is always significantly superior to other benchmark models. Our work contributes to guiding carbon price modeling to help regulators and managers accurately grasp carbon price signals. [ABSTRACT FROM AUTHOR]

Two series of phosphors of LaSr 1-x GaO 4 :xCr3+ and La 1-x SrGaO 4 :xCr3+were synthesized by a high-temperature solid-state method under the same experimental conditions. The phase structure, surface topography, luminescence properties and luminescence mechanism of phosphors were investigated. LaSrGaO 4 host exhibits a narrow emission band peaks at 716 nm which comes from the intrinsic defects. LaSr 1-x GaO 4 :xCr3+ and La 1-x SrGaO 4 :xCr3+ phosphors show emission spectra with the same shape to the host, while the luminous intensity improved greatly. From the analysis of low temperature spectra and decay lifetimes of the samples, it can be concluded that Cr3+ show no intrinsic luminescence in the LaSrGaO 4 host. The analysis of TL spectra proved that the defect concentration was increased by Cr3+ doping, and enhanced the intrinsic luminescence. The emission spectrum of the LED device based on the LaSr 0.999 GaO 4 :0.001Cr3+ phosphor almost coincides with the absorption spectrum of the P FR phytochrome, which indicated the pc-LED have potential application in the field of plant lighting, especially for the study of the independent regulatory mechanism of P FR. [ABSTRACT FROM AUTHOR]

• Spectrally resolved DNI was tested for an entire year in Beijing. • The spectra can be represented in five-dimensional data by an autoencoder. • Hierarchical clustering was adopted to obtain ten reference spectra in the case. • Novel local reference spectra can characterize solar resources throughout the year. • The superiority of the new reference spectra over ASTM AM1.5D was verified. The established reference spectrum (ASTM AM1.5) based on mid-latitudes is still the most frequently used standard in design and simulation in various fields worldwide, however, the solar spectrum varies with climate and time, which significantly affects the evaluations of solar energy utilization. This study proposes a novel reference spectrum analysis method to establish several local reference spectra, in this case, based on 147,374 spectra in Beijing, which can characterize solar resources throughout the year. The dataset consists of spectra of direct normal irradiance, and a deep learning autoencoder is adopted to extract the intrinsic features of each spectrum for clustering. 10 clusters are finally divided by agglomerative hierarchical clustering, and 10 local reference spectra were identified from each cluster by correlation analysis. The results show that the shape of new reference spectra shifts to the short wave as the irradiance increases, and the average photon energy increases from 1.069 eV to 1.456 eV. The new local reference spectra are compared with the standard spectrum AM1.5D to show the influence of shape variations, and it reveals 61% maximum differences among photovoltaic applications. The superiority verified new reference spectra could be further used to optimize local solar technologies design and guide photovoltaic material development. [ABSTRACT FROM AUTHOR]

The singular spectrum analysis (SSA) is a relatively new method for decomposing time series into separable and interpretable series (i.e., trend, periodic, and irregular components). Here, the ionospheric variability in the peak electron density (NmF2) observations provided by FORMOSAT-3/Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation measurements during 2009–2019, which completely covers solar-cycle 24, was examined using the nonparametric method (SSA). This study identified different temporal patterns inherent in the COSMIC data, which can be employed to reconstruct/model noise-free time series. Based on a proper choice of SSA parameters, it was observed that SSA can be employed to extract various components of these datasets. Additionally, the results showed that the slowly varying component (trend) was largely influenced by solar activity and closely followed the behavior of the sunspot cycle. The SSA method demonstrated seasonal patterns (the semiannual component). Based on the patterns, the reconstructed series for each of the selected components were separately modeled with a corresponding fit function using the 10.7 cm solar proxy, which prior be smoothed by Spline fitting. It was observed that the polynomial function efficiently modeled the trend component with R2 = 0.95, while the harmonic function adequately represented the semiannual component with R2 = 0.97. To validate the proposed model, the data were estimated for the time interval from January 2020 to August 2022, which represented the ascending phase of the ongoing solar-cycle 25. The results revealed that the modeled data correlated with the observed COSMIC-2 data with a high correlation coefficient (0.95). These findings indicate that the underlying model can effectively describe the behavior of the electron density during the investigated period, and the SSA method is particularly powerful for analyzing nonstationary time series and capable of identifying sub-time series (trends along with seasonal periodic components). [ABSTRACT FROM AUTHOR]

• This paper presents a solution methodology for the rotor system with bolted joint. • The presented solution methodology is verified by the Newmark method. • The 3X and 5X of the rotating frequency are found in the spectrum. • The rotating speed corresponding to 5X's peak precedes the critical speed. • The findings of spectral characteristics are verfied by the experimental test. The bolted joint is commonly used to connect several parts of aero-engine rotor system. Several papers have studied the nonlinear vibration responses of bolted rotor systems. However, the frequency spectrum characteristics of bolted rotor systems are not fully revealed. Aiming at this issue, this study develops a dynamic model of the bolted rotor system, where the piecewise stiffness characteristic is considered. A solution methodology is presented by incorporating the piecewise stiffness into the incremental harmonic balance method. The effects of unbalance and preload on the dynamic characteristics are discussed. Moreover, the stiffness and damping of the support structure and bolted joint are identified based on the particle swarm optimization algorithm and experimental results. Furthermore, the experimental study on a bolted rotor test rig is conducted to verify the accuracy of the identified parameters and the model. The simulation and experimental results indicate that 3X and 5X of the rotating frequency can be observed. Besides, the rotating speed corresponding to 5X's peak is different from the critical speed, and the peak of 5X precedes the primary resonance peak. [ABSTRACT FROM AUTHOR]

In the present work, a series of Sm3+-doped MO-ZnO-B 2 O 3 –P 2 O 5 (M = Mg, Ca, Sr, Ba) glasses were prepared. The glass structure and luminescence properties were investigated by XRD, DSC, IR, absorption spectroscopy, Judd-Ofelt theory and photoluminescence spectra. The J-O parameters of Sm3+-doped glasses follow the trend of Ω 4 ＞Ω 6 ＞Ω 2. Under the excitation of 401 nm Xenon lamp, Sm3+-doped glasses exhibited four emissions from the transitions of 4G 5/2 →6H J/2 (J = 5, 7, 9, 11) in the visible spectra. The luminous intensity of Sm3+ increases with the asymmetry in local environments and decreases with the increasing radius of the alkaline-earth cation. Among the as-prepared glass, the Sm3+-doped glass containing magnesium oxide exhibits higher values of stimulated emission cross-section (2.18 × 10−21 cm2), gain bandwidth (1.40 × 10−27 cm3), and optical gain (3.83 × 10−24 cm2). All the Sm3+-doped glasses show intense orange light in the CIE 1931 chromaticity diagram with a high color purity exceeding 99%. In addition, the time-resolved emission spectra reveal the decay process of the Sm3+ ions for the transitions 4G 5/2 → 6H 7/2 and 4G 5/2 → 6H 9/2 in the glass containing magnesium oxide. It suggests that Sm3+-doped alkaline-earth zinc borophosphate glasses could be a potential candidate for reddish-orange light-conversion fluorescent materials based on the ultraviolet light-emitting diode. [ABSTRACT FROM AUTHOR]

Raw bioelectrical impedance measurements are often used as a prognosticator of health status because of their association with disease states and malnutrition. Although studies consistently show the effect of physical characteristics on bioelectrical impedance, few investigations describe the effect of race, particularly for Black adults, and many bioelectrical impedance standards were produced from primarily White adults almost 2 decades ago. Therefore, this study sought to evaluate the racial differences in bioelectrical impedance measurements using bioimpedance spectroscopy between non-Hispanic White and non-Hispanic Black adults matched for age, sex, and body mass index. We hypothesized that Black adults would have a lower phase angle from higher resistance and lower reactance compared with White adults. One hundred non-Hispanic White (n = 50) and non-Hispanic Black (n = 50) males (n = 34) and females (n = 66) matched for sex, age, and body mass index completed this cross-sectional study. Participants underwent several anthropometric assessments, including height, weight, waist circumference, hip circumference, bioimpedance spectroscopy, and dual-energy X-ray absorptiometry. Bioelectrical impedance measures of resistance, reactance, phase angle, and impedance were all collected at frequencies of 5, 50, and 250 kHz and bioelectrical impedance vector analysis was performed using 50-kHz data. There were no significant differences for any anthropometric variable between Black and White participants in the total sample or by sex groups. In addition, there were no significant racial differences for any bioelectrical impedance assessment, including bioelectrical impedance vector analysis. Differences in bioelectrical impedance are likely not a function of race between Black and White adults and concerns regarding its utility should not be based on this characteristic. After accounting for all relevant physical attributes known to influence bioelectrical impedance measurements, assessments, including bioimpedance vector analyses, were not significantly different between non-Hispanic Black and White adults. Concerns regarding its utility for Black adults should not be based on race. The absence of race-dependent bioelectrical values may improve clinical confidence and prognostic value in these techniques and limit racial health disparities for Black adults. BMI, body mass index. [Display omitted] [ABSTRACT FROM AUTHOR]

Portable near-infrared (NIR) lighting source stimulates great efforts to exploit NIR phosphor-converted LEDs (pc-LEDs) that push the rapid development of broadband NIR-emitting phosphors. Although Cr3+-activated NIR phosphors designed by multisites occupation strategy show significant potential in emission bandwidth, poor spectral stability caused by different thermal quenching behaviors is a brake on practical application due to different local structure around Cr centers. One-site-based NIR phosphors seem to be an effective method to solve aforementioned problem. Herein, we report a type of new ultra-broadband one-site-based NIR-emitting phosphors NaSc 1-x P 2 O 7 :xCr3+ (NSP:xCr3+) with emission at 910 nm and full width at half maximum (FWHM) of up to ∼200 nm. Their FWHM value exceeds all one-site-based Cr3+-activated phosphors and some multiple-sites ones. Structural analysis and low-temperature spectra demonstrate that such impressive broadband NIR emission originates from Cr3+ occupying at single octahedral Sc site. At 425 K, integrated emission intensity of NSP:0.04Cr3+ phosphor maintains 53.8% of room temperature. A NIR pc-LED prototype is fabricated by using NSP:0.04Cr3+ phosphor with a blue LED chip, and its multipurpose applications in non-destructive detection, night vision and analysis of foodstuff are demonstrated. These findings indicate that broadband NSP:0.04Cr3+ NIR phosphor enabled by one-site occupation strategy has potential prospect for multipurpose NIR pc-LEDs applications. [ABSTRACT FROM AUTHOR]

• In contrast to methods such as power spectrum and wavelet analysis, dipole source localization can determine the location and size of activated brain regions during stimulation. • The driver's right intraorbital superior and the infraorbital frontal gyrus regions were significantly activated during visually distracted driving. • The left and right dorsolateral superior frontal gyrus regions were significantly activated during auditory distracted driving. • The right intraorbital superior, infraorbital, and dorsolateral superior frontal gyrus were significantly activated during cognitive distraction. • Driving distracted drivers were most affected in prefrontal cortical regions, especially in the right frontal cortical region. Electroencephalogram (EEG) was used to analyze the differences in brain area activation correlations between driving distraction (visual distraction, auditory distraction, and cognitive distraction) and normal driving. Thirty subjects participated in this study. Three subtasks were designed, which occurred randomly during driving simulation, to investigate the effects of different distractions on the drivers' neural activity. The drivers' right intraorbital superior frontal gyrus and right infraorbital frontal gyrus were significantly activated during visual distraction driving, while the superior frontal gyrus, right dorsolateral region were significantly activated during auditory distracted driving, and the right intraorbital superior frontal gyrus, right infraorbital frontal gyrus and superior frontal gyrus, and right dorsolateral region were significantly activated during cognitive distraction. This intrinsic neural activity in brain regions is expressed through extrinsic driving performance. It was found that auditory distracted driving, with the lowest activation in the right frontal lobe, had the least effect on lateral control of the vehicle, and cognitive distracted driving, with the highest activation in the right frontal lobe, had the greatest effect on lateral control of the vehicle. Therefore, we suggest that prefrontal cortical areas, especially the right frontal cortical area, are most affected by distracted driving. [ABSTRACT FROM AUTHOR]

We analyse how the spectrum of the anisotropic Maxwell system with bounded conductivity σ on a Lipschitz domain Ω is approximated by domain truncation. First we prove a new non-convex enclosure for the spectrum of the Maxwell system, with weak assumptions on the geometry of Ω and none on the behaviour of the coefficients at infinity. We also establish a simple criterion for non-accumulation of eigenvalues at i R as well as resolvent estimates. For asymptotically constant coefficients, we describe the essential spectrum and show that spectral pollution may occur only in the essential numerical range W e (L ∞) ⊂ R of the quadratic pencil L ∞ (ω) = μ ∞ − 1 curl 2 − ω 2 ε ∞ , acting on divergence-free vector fields. Further, every isolated spectral point of the Maxwell system lying outside W e (L ∞) and outside the part of the essential spectrum on i R is approximated by spectral points of the Maxwell system on the truncated domains. Our analysis is based on two new abstract results on the (limiting) essential spectrum of polynomial pencils and triangular block operator matrices, which are of general interest. We believe our strategy of proof could be used to establish domain truncation spectral exactness for more general classes of non-self-adjoint differential operators and systems with non-constant coefficients. [ABSTRACT FROM AUTHOR]

• Frescoes replicas using red pigments were prepared to develop a smartphone-based methodological approach. • Colour properties were measured by spectrocolorimeter and smartphone. • Chemometric classificatory methods were used to identify red pigments colors. • Low classification errors were obtained employing LDA and SVC classifying methods. • A new and easy approach employing mobile phones to discriminate red pigments is presented. The characterization of red pigments in frescoes wall paintings has been of great interest for researchers to better understand raw material procurement dynamics, pigment receipts, stylistic evolution and to assess their conservation state. In this study a non-destructive colorimetric approach implementing a smartphone-based method was developed in order to be able to distinguish between three pigments made from minium, haematite and cinnabar minerals, and also mixed pigments, preparing frescoes mock-ups following the roman receipt described by Vitruvius. Portable FT-IR, Raman spectroscopy, portable XRF and visible reflectance spectra analyses were carried out as reference methods for smartphone colorimetry results validation. Employing a reference colour sheet to control changing lighting conditions, different chemometric approaches have been developed and tested, cross-referencing standard analytical results with the data obtained by smartphone. Overall, using only colour parameters from the smartphone, a Linear Discriminant Analysis and a Support Vector Classifier were tested to efficiently classify each sample based on the red pigment used, with low prediction errors. This work shows the potential of smartphones as cheap, fast and user-friendly analytical devices for the screening of frescoes, and as a prior selective step before carrying out further more expensive and specialized analyses. [Display omitted] [ABSTRACT FROM AUTHOR]

A detailed analysis of the bremsstrahlung spectrum at nonrelativistic electron scattering on argon and xenon is carried out. It is shown that the approximate formulas widely used for the description of bremsstrahlung spectra lead to predictions that significantly differ from the exact results. In the limit when the photon frequency tends to zero, a rigorous proof of the relationship between the spectrum of the bremsstrahlung with a transport cross section of electron scattering on an atom is given. This proof does not require any assumptions about the dependence of the scattering phases on energy. For electron energies lower than the luminescence threshold, it is shown that the predictions for a number of radiated photons obtained by the exact formula are in good agreement with the available experimental data. [ABSTRACT FROM AUTHOR]

Background: Surgical wound excision is a necessary procedure for burn patients that require the removal of eschar. The extent of excision is currently guided by clinical judgement, with excessinto healthy tissue potentially leading to excessive scar, or inadequate debridement increasing risk of infection. Thus, an objective real-time measure to facilitate accurate excision could support clinical judgement and improve this surgical procedure. This study was designed to investigate the potential use of Rapid evaporative ionisation mass spectrometry (REIMS) as a tool to support data-driven objective tissue excision.Methods: Data were acquired using a multi-platform approach that consisted of both Rapid Evaporative Ionisation Mass Spectrometry (REIMS) performed on intact skin, and comprehensive liquid chromatography-mass spectrometry (LC-MS/MS) lipidomics performed on homogenised skin tissue extracts. Data were analysed using principal components analysis (PCA) and multivariate orthogonal projections to latent squares discriminant analysis (OPLS-DA) and logistic regression to determine the predictability of the models.Results: PCA and OPLS-DA models of the REIMS and LC-MS/MS lipidomics data reported separation of excised and healthy tissue. Molecular fingerprints generated from REIMS analysis of healthy skin tissue revealed a high degree of heterogeneity, however, intra-individual variance was smaller than inter-individual variance. Both platforms indicated high levels of skin classification accuracy. In addition, OPLS-DA of the LC-MS/MS lipidomic data revealed significant differences in specific lipid classes between healthy control and excised skin samples; including lower free fatty acids (FFA), monoacylglycerols (MAG), lysophosphatidylglycerol (LPG) and lysophosphatidylethanolamines (LPE) in excised tissue and higher lactosylceramides (LCER) and cholesterol esters (CE) compared to healthy control tissue.Conclusions: Having established the heterogeneity in the biochemical composition of healthy skin using REIMS and LC-MS/MS, our data show that REIMS has the potential to distinguish between excied and healthy skin tissue samples. This pilot study suggests that REIMS may be an effective tool to support accurate tissue excision during burn surgery. [ABSTRACT FROM AUTHOR]

To analyze the effect of PFN content on the microstructure and electrical properties of x Pb(Fe 0.5 Nb 0.5)O 3 –(0.57− x)Pb(Ni 1/3 Nb 2/3)O 3 –0.43Pb(Zr 0.3 Ti 0.7)O 3 , the doping of x PFN–PNN–PZT) were systematically studied with 0.015 ≤ x ≤ 0.075. XRD patterns and Raman spectra analysis reveal that PFN diffuses into PNN–PZT perovskite lattice and forms new quaternary solid solution. With the increase of PFN content x , the proportion of rhombohedral (R) phase decreases gradually, whereas the proportion of tetragonal (T) phase displays a contrary trend. In particular, R – T coexistence near MPB was observed at x = 0.045. Meanwhile, optimized electrical properties of d 33 = 961 pC/N, k p = 0.716, ε r = 6298, and tan δ = 3.1% are achieved for the 0.045PFN–PNN–PZT ceramics. Moreover, the ceramics at MPB showed larger remnant polarization P r = 24.55 μC/cm2, smaller coercive field E c = 0.36 kV/mm, and lower dielectric relaxor degree γ = 1.813. All these results reveal that the enhanced electrical properties could be attributed to synergistic phase boundary motion, dielectric relaxor behavior and ferroelectric hysteresis effect. [ABSTRACT FROM AUTHOR]

The reason for quiescent intervals and isolated emission episodes in gamma-ray burst (GRB) light curves is still not well understood. Probing these questions further requires the study of the spectral characteristics and properties of the outflow of such GRBs. GRB 120709A is a burst with three distinct emission episodes, separated by quiescent periods lasting several seconds. The episodes are comparable with each other in terms of peak flux and duration. The GRB was observed by the Fermi LAT and GBM instruments, covering over six orders of magnitude of energy. In this work, we carry out the time-integrated and time-resolved spectral analysis of GRB 120709A. We use these results to study the temporal variation of its parameters. In particular, we find that the peak energy of the spectrum of each episode traces the flux of those episodes. We also study and parameterise the correlation between the isotropic luminosity and intrinsic peak energy. Finally, we determine the parameters of the outflow based on gamma-gamma opacity calculations. We find that if we require the MeV emission to occur above the photosphere, then the ratio of the GeV and MeV emission radii can not be greater than ∼ 1.2. This implies an internal origin of the GeV emission. This also allows us to estimate the average value of the Lorentz factor to be in the ∼ 100–200 range. We also evaluate the photospheric and MeV emission radii and find them to be in the (4.5–5.3) × 10 12 cm and (2.1–5.2) × 10 14 cm ranges, respectively. We note the limitations of this exercise due to the relative faintness of the GRB which prevents us from doing a very fine time-resolved analysis or fitting the spectra with multi-component models. We also discuss GRB 120709A in the context of models for distinct emission episodes and quiescent intervals. [ABSTRACT FROM AUTHOR]

The utilization of near-infrared (NIR) spectroscopy, in conjunction with chemometric techniques, has been widely used in a variety of sectors, including agricultural production and pharmaceutical production. Nevertheless, the laborious and arduous procedure of gathering samples and evaluating their physicochemical properties leads to relatively limited training set sizes for modeling. This problem severely limits the optimization and practical application of NIR spectrum analysis models. The Safer Active Semi-Supervised Sample Augmentation Learning Model (Safer-AS3A) proposed in this paper tries to address the problem by incorporating active learning (AL) and semi-supervised learning (SSL) techniques. Experiments were conducted on two sets of publicly available NIR spectral datasets, and the Safer-AS3A model was compared to other models with similar characteristics. The experimental results indicate that the Safer-AS3A model proposed in our study outperforms comparable models in terms of accuracy and robustness when dealing with scenarios having a limited number of labeled samples. Furthermore, after the training set was expanded with the Safer-AS3A model, the Partial least squares regression (PLSR), Bayesian ridge regression (BRR), and Support vector regression (SVR) models on the Diesel dataset improved their R 2 on the test set by 5.923 %, 3.018 %, and 7.331 %, respectively, compared to the models using only the labeled sample set. On the other hand, the Ridge regression (RR), BRR, and SVR models on the test set on the Shoot dataset improved the R 2 by 4.169 %, 4.449 %, and 11.597 %, respectively. Overall, the Safer-AS3A model can effectively expand the NIR spectral dataset and considerably improve the performance of the NIR spectral analysis model. Using the AL method, the SSL method, and the co-training method together, a novel and effective method is presented for generating high-quality pseudo-labels. This method opens up new avenues for enhancing the efficiency and precision of NIR spectrum analysis. It also provides novel perspectives on sample diversification and prospective applications in other disciplines. [Display omitted] • A deep active learning method is developed to analyze near-infrared spectroscopy data. • The stability principle and voting mechanism are added to the confidence evaluation of pseudo-labeling. • The co-training method effectively alleviates the problem of insufficient labeled spectral samples. [ABSTRACT FROM AUTHOR]

The main problem that arises in the mobility spectrum analysis (MSA) is the appearance of additional spectral lines, which are not related to real physical processes and transport mechanisms. The paper proposes a simple model of systematic errors occurring in magneto-transport measurements and investigates their impact on this adverse phenomenon. The analysis was carried out for typical mobility spectra characteristic of single- and dual-carrier transport. On the basis of numerical experiments, heuristic rules were formulated that can be helpful in distinguishing real spectral lines from false peaks caused by measurement errors. • A simple model of systematic errors in transport measurements has been proposed. • The impact of these errors on the mobility spectra has been investigated. • In the case of two-carrier transport, one additional spectral line always shows up. • Such artificial (ghost) peak has unique properties that allow it to be identified. [ABSTRACT FROM AUTHOR]

It can be foreseen that the global demand for natural gas (NG) will show an increase trend in the upcoming decades. Solidified Natural Gas (SNG) having a high energy density provides an alternative solution for the storage and transportation of NG. In this study, our focus lies on investigating the impact of 1,3-dioxane and L-tryptophan on mixed CH 4 /dioxane hydrate formation from multiple perspectives including thermodynamic, Raman spectra, and kinetics. The thermodynamic experimental results confirmed that the mixed CH 4 /dioxane hydrate can form at a moderate conditions and shows high dissociation enthalpies. A thermodynamic model based on van der Waals and Platteeuw model was applied for predicting equilibrium conditions of the Hydrate–Liquid–Vapor system, yielding an average absolute deviation ranging from 1.7% to 3.9%. Raman spectra results re v ealed that there is a two–stage growth mechanism for mixed CH 4 /dioxane hydrates. Kinetic results demonstrated that the system of CH 4 /5.56 mol% dioxane/water shows the highest gas uptake of 91.1 (±0.5) v /v at 287.15 K and 10.0 MPa, compared to other systems. Moreover, the addition of 1000 ppm L-tryptophan can reduce the time to reach 90% uptake (t 90), showing a value of 19.9 (±1.8) minutes. The findings derived from this research are instrumental in developing the SNG technology. [Display omitted] • Methane storage via mixed CH 4 /dioxane hydrates was investigated. • A thermodynamic model for mixed CH 4 /dioxane hydrate was developed. • In-situ Raman spectra analysis of hydrate formation was conducted. • The effects of L-tryptophan on hydrate formation kinetics were studied. • Up to 91.1 v /v of methane uptake is achieved at moderate conditions. [ABSTRACT FROM AUTHOR]

The Qiye Shen'an tablet is formulated using total saponins extracted from Notoginseng stems and leaves. At present, the study on its chemical composition remains scarce and the quality control indicators are limited, which seriously hindering the effective quality control and clinical research. Hence, this study aims to comprehensively identify and characterize the Qiye Shen'an tablet while controlling its main component contents. To achieve a comprehensive understanding of this tablet, an ultra-high performance liquid coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS) method was employed for its separation and characterization. Through the analysis of 99 batches of Qiye Shen'an tablet produced by 9 enterprises, the characteristic quantitative components were further obtained. A total of 113 compounds were characterized and identified, among which 17 representative compounds were selected, and the ultra-high performance liquid-triple quadrupole tandem mass spectrometry (UPLC-TQS-MS/MS) method was established for further quantitative determination. It has been successfully applied to the content determination of 99 batches of Qiye Shen'an tablet, and a new quality control method is being formed. This study provides a new method for chemical spectrum analysis and determination of labeled compounds of Qiye Shen'an tablet, and lays a solid foundation for further study of potential active ingredients and comprehensive quality evaluation. • The qualitative analysis of Qiye Shen'an tablet was reported for the first time. • A total of 113 compounds of Qiye Shen'an tablet were deduced by UPLC Q-TOF/MS. • Seventeen representative compounds were quantified simultaneously in 38 min. [ABSTRACT FROM AUTHOR]

• Four hemicyanines with different structures are synthesized and characterized successfully, and the single crystal structure are collected. • Through the single crystal data, the electrostatic potential, HOMO&LUMO and other information are obtained. • The optical properties of hemicyanines are analyzed by combining the calculated results and experiments. Four hemicyanine dyes (1–4) containing indole group and bearing different substituent in phenyl ring were successfully synthesized. In this study, NMR, elemental analysis and single-crystal analysis were employed to confirm the structures of four newly synthesized compounds. Additionally, electrostatic potential calculations were conducted to enhance the dataset of hemicyanines comprehensively. Furthermore, the optical properties of the resulting hemicyanines were evaluated in organic solvents. The elucidation of the single-crystal structure of the material allows for a deeper understanding of the relationship between its intrinsic structure and properties. This systematic investigation represents an essential initial step towards the development of related photoactive agents for light-based diagnostic and therapeutic applications. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Visible near infrared spectroscopy can be used to detect four heavy metals in Jiaozhou Bay, China. • The model established in this study have an RPD of over 1.7. • This study provides an effective reference for ecological environment protection and resource development of the Jiaozhou Bay. As an important component of biogeochemical cycle in coastal ecosystems, sediments are the sink of heavy metals. Therefore, distribution and dynamics of heavy metals in sediments could assess ecological quality and predict ecological risks. In the new era, rapid and green technology are highly needed, especially that could determine multi-parameters simultaneously. Here, we explored a new method to rapidly determine concentrations of heavy metals in sediments by visible and near infrared reflectance spectroscopy (VIRS). We sampled sediments in the Jiaozhou Bay, China, collected their reflectance spectra, and measured concentrations of four heavy metals (As, Cr, Cu, and Zn). Heavy metal models were established and evaluated using substances highly correlated with heavy metals. This study provides an effective reference for rapid analysis of As, Cr, Cu, and Zn simultaneously in sediments, at least in the Jiaozhou Bay, and for ecological environment protection and resource development of the Jiaozhou Bay. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hybrid Transformer network, TMNet, was developed to identify SERS spectra. • Transformer encoder was used to extract precise features of the sequential spectra. • Classification results were generated through features by the multi-layer perceptron. • TMNet excellently identified drugs in hair and urine in different noise scenarios. Surface-enhanced Raman Spectroscopy (SERS) is extensively implemented in drug detection due to its sensitivity and non-destructive nature. Deep learning methods, which are represented by convolutional neural network (CNN), have been widely applied in identifying the spectra from SERS for powerful learning ability. However, the local receptive field of CNN limits the feature extraction of sequential spectra for suppressing the analysis results. In this study, a hybrid Transformer network, TMNet, was developed to identify SERS spectra by integrating the Transformer encoder and the multi-layer perceptron. The Transformer encoder can obtain precise feature representations of sequential spectra with the aid of self-attention, and the multi-layer perceptron efficiently transforms the representations to the final identification results. TMNet performed excellently, with identification accuracies of 99.07% for the spectra of hair containing drugs and 97.12% for those of urine containing drugs. For the spectra with additive white Gaussian, baseline background, and mixed noises, TMNet still exhibited the best performance among all the methods. Overall, the proposed method can accurately identify SERS spectra with outstanding noise resistance and excellent generalization and holds great potential for the analysis of other spectroscopy data. [ABSTRACT FROM AUTHOR]

[Display omitted] • A portable Raman spectroscopy detection system was established. • The spectral data from peanut samples was obtained using this system. • A hybrid strategy for variable selection was proposed. • This study used Raman spectra and hybrid strategy to detect AFB 1 in peanuts. Aflatoxin B 1 (AFB 1), among the identified aflatoxins, exhibits the highest content, possesses the most potent toxicity, and poses the gravest threat. It is commonly found in peanuts and their derivatives. This study employs Raman spectroscopy to monitor the AFB 1 levels in moldy peanuts, providing a reliable theoretical basis for peanut storage management. Firstly, different degrees of moldy peanuts are spectrally characterized using a portable Raman spectrometer. Subsequently, a two-step hybrid strategy for feature selection is proposed, combining backward interval partial least squares (BiPLS) and variable combination population analysis (VCPA), aiming to simplify model complexity and enhance predictive accuracy. Finally, partial least squares (PLS) regression models are constructed based on different feature intervals and wavelength points. The research results reveal that the PLS regression model using the optimized feature intervals and wavelength points exhibits improved predictive capability and generalization performance. Notably, the BiPLS-VCPA-PLS model, established through the two-step optimization, selects nine wavelength variables, achieving a root mean square error of prediction (RMSEP) of 33.3147 μ g ∙ k g - 1 , a correlation coefficient of the prediction set (R P) of 0.9558, and a relative percent deviation (RPD) of 3.4896. These findings demonstrate that the two-step feature optimization method, combining feature interval selection and feature wavelength selection, can more accurately identify optimal variables, thus enhancing detection efficiency and predictive precision. [ABSTRACT FROM AUTHOR]

Identification of components in pesticide mixtures has been a major challenge in spectral analysis. In this paper, we assembled monolayer Ag nanoparticles on Thin-layer chromatography (TLC) plates to prepare TLC-Ag substrates with mixture separation and surface-enhanced Raman scattering (SERS) detection. Spectral scans were performed along the longitudinal direction of the TLC-Ag substrate to generate SERS spectra of all target analytes on the TLC plate. Convolutional neural network classification and spectral angle similarity machine learning algorithms were used to identify pesticide information from the TLC-SERS spectra. It was shown that the proposed automated spectral analysis method successfully classified five categories, including four pesticides (thiram, triadimefon, benzimidazole, thiamethoxam) as well as a blank TLC-Ag data control. The location of each pesticide on the TLC plate was determined by the intersection of the information curves of the two algorithms with 100 % accuracy. Therefore, this method is expected to help regulators understand the residues of mixed pesticides in agricultural products and reduce the potential risk of agricultural products to human health and the environment. [Display omitted] • A simple method for preparation of TLC-Ag substrate with separation and SERS detection. • Machine learning algorithm analyze TLC-SERS spectra to identify pesticides mixtures. • The combination of the two algorithms ensures accuracy of the identification results. • Accurate identification of analytes even the analytes overlap on the TLC path. [ABSTRACT FROM AUTHOR]

Moving weather systems determine the history of wind variations with patterns as the systems transit through the ocean. These weather systems are integrated entities that can provide a system level perspective. A vessel-based survey repeatedly occupying a 30-km transect 12 times in 36 h provided non-aliased measurements of velocity field that showed how the along-shelf transport varied by more than three-fold in response to a transiting high-pressure weather system following an atmospheric cold front. To further illustrate the impact of different weather systems, we analyzed time series data from moored ADCPs, which showed influence on the velocity field from infrequent summertime cold fronts and remote hurricanes moving through the region, one on the west and the other on the east of the study site. Rotary spectrum analysis showed that the flow field rotated mostly clockwise with a smaller but non-negligible counterclockwise component, consistent with near inertial oscillations mixed with weak tidal currents. A theoretical model is presented by a Laplace transform and a general relationship between the velocity field and forcing functions is obtained, which shows that the contributions to the rotary velocity field from various forcing functions are through mathematical convolutions between the forcing functions and the complex frictional-rotary inertial function (CFRIF). These convolutions include an integrated effect of history of the forcing. CFRIF is effectively a frictional rotary filter that favors inertial oscillations. The wind-stress induced velocity field over a few days is computed and it shows significant variations after the passage of a cold front, with a magnitude consistent with observations. The wind-stress induced velocity is a few times greater than the density driven flow during the ship-based observations. The weather systems passing through the region can impact coastal currents causing a great variability over short time scales. [ABSTRACT FROM AUTHOR]

The high-resolution broadband LIBS spectrum is typically acquired using an echelle spectrometer and array detectors. However, the full frame (i.e. , echellogram) captured by detector is commonly converted to 1D spectrum for the further analysis, which would both limit the detection speed of LIBS and potentially degenerate the analytical performance. In this work, we propose an echellograms-based analysis method for the quantification of minor metal elements in steel. Two metal elements, Mn and Ti, are chosen to validate the feasibility of the analytical method. The LASSO algorithm is used to build the multivariate regression model using LIBS spectra and echellograms respectively. The analytical performance obtained with the echellograms-based model is compared with that of spectra-based model. The efficiency of the echellograms-based quantitative analysis method is demonstrated with better prediction accuracy and precision. Notably, the echellogram-based regression model involves only tens to thousands of pixels from the echellogram, which can be selectively read out using a CMOS detector. The combination of echellogram-based quantitative analysis method and CMOS detector provides new ideas for high-frequency LIBS detection. [Display omitted] • Accurate determination of minor elements in steel using echellograms-based analysis method of LIBS. • Comparison of analytical performance between spectra-based regression models and echellograms-based regression models. • Observing the influence of echellogram's size on analytical performance. • Analyzing the pixels involved in regression model and corresponding positions in echellogram. [ABSTRACT FROM AUTHOR]

Hydrothermal and thermolysis techniques were used to create ZnWO 4 and 0.9ZnWO 4 -0.1MS (M = Cd, Zn, Pb) samples. The formed phases in each sample and their structure and microstructure were examined using Raman spectroscopy, Fourier-transform infrared spectroscopy and Rietveld refinement of Synchrotron x-ray diffraction data. The composition and morphology of the formed samples were investigated via scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS). The average crystallite size remains relatively constant regardless of the different metal chalcogenides. MS/ZnWO 4 samples have two distinct morphologies. The UV diffuse reflectance spectroscopy (UV-DRS) technique is used to investigate the linear and nonlinear optical parameters for different samples. Alloying ZnWO 4 with CdS or PbS affects the photo response region of the sample to include visible light. MS/ZnWO 4 (MS=CdS, ZnS, PbS) samples have optical band gap values of 2.56, 2.43, 2.99 and 3.1 eV, respectively. The CdS/ZnWO 4 and ZnS/ZnWO 4 samples exhibit the highest refractive index and optical dielectric constant values within the visible range. CdS or PbS/ZnWO 4 samples show the highest nonlinear optical parameters values within the visible range. The impact of MS samples on the photoluminescence emission of ZnWO 4 was explored. The CIE chromaticity diagram reveals that MS/ZnWO 4 (M = Zn and Pb) samples display a different degree of blue color while CdS/ZnWO 4 sample reveals green-yellow colors. • Raman spectra analysis confirmed the formation of CdS phase, nonexistence of the ZnS phase and could not detect PbS phase. • The values of n and k are influenced by the measured range of wavelengths and the type of alloying sample (MS) with ZnWO 4. • All samples exhibit a wide-ranging emission in the blue-green region. • The examined samples become more sensitive to daylight. [ABSTRACT FROM AUTHOR]

This study aimed to reduce surface configuration defects and improve the service performance of the configuration surface. The configuration was prepared using the principle of preset powder feeding laser cladding. Macroscopic and microscopic properties of the shallow configuration were tested to understand the mechanism behind the preset cladding material's ability to repair defects and improve surface hardness, and the preparation process of the shallow configuration was obtained. Finally, the method's potential for improving the wear resistance of the configuration surface was evaluated through friction and wear tests. The results indicate that the flow of molten preset powder can fill in pores, leading to the formation of a dense cladding layer on the configuration surface. This process also minimizes the generation of defects and holes. The incorporation of hard phases, such as TiN, Ti 2 N, and the solid solution (Ti, W)C 1-X , positively influences the improvement of surface hardness and wear resistance of shallow configuration. When the average laser energy density ranges from 70 to 120 W·cm−2, the average microhardness of the shallow configuration surface is elevated by 13.4% compared to that of the conventional configuration surface. The friction force on the shallow configuration surface is 13.1% lower than that on the conventional configuration surface when the laser power is set to 80%, the scanning speed is maintained at 1500 mm/s, the scanning passes are 9, the spacing between configurations is 130 μm, and the configuration diameter is 50 μm. This technique presents a novel approach to producing configuration surfaces with enhanced quality. • A new preparation process is used to prepare the shallow configuration based on the principle of laser cladding. • The microscopic properties of the surface were detected by scanning electron microscopy, EDS energy spectrum analysis, X-ray diffractometer and microhardness tester. • The surface friction and wear characteristics were detected by friction and wear test. • The shallow configuration parameters and laser preparation parameters were optimized. [ABSTRACT FROM AUTHOR]

• Failure modes of the crusher's screen plate are fracture, crack, slimming and wear. • Main failure mechanisms are abrasive wear, fatigue and brittle failure. • Root causes of the failures are direct impact, defects and poor-grade materials. • Good maintenance and proper material selection are proposed mitigation measures. The screen plate, a critical component within a ring hammer crusher (also known as a ring granulator or rolling ring crusher), plays a vital role in the secondary crushing of coal. Functioning both as a platform for coal crushing and as a sieve to achieve the desired coal size, it is essential to understand and examine its failure characteristics to enhance its mechanical and wear resistance properties in coal handling applications. This study thoroughly explored the failure modes, mechanisms, and underlying causes of screen plate failures. Microscopic techniques such as optical microscopy (OM), scanning electron microscopy (SEM), Vickers microhardness test and spectrochemical analysis were utilised to identify the failure mechanism. Failure modes identified from the macroscopic analysis were discharged hole widening, hole wall break-off, plate edge crack, plate fracture, one-sided edge slimming, and general surface wear of the screen plate. The fractographic and wear track analysis identified the principal failure mechanisms of three-body abrasive wear, two-body sliding abrasion wear, shear-induced fatigue fracture and brittle shear fracture. The root causes of the failures are the rotor's direct impact, defects in the parent material, the presence of hard materials in the coal and the use of unsuitable steel grade in the screen plate manufacturing. The service life of the screen plate can be improved through proper material selection, uniform crusher feeding, surface modification of the surface of the "as purchase" screen plate with appropriate wear-resistant materials, and adherence to good maintenance practices. [ABSTRACT FROM AUTHOR]

[Display omitted] • An initial reaction mechanism for plasma-assisted steam reforming of toluene. • Over 60 % toluene was converted into small molecules (H 2 , CO, C 2 H 2) at 300 °C. • Combining kinetic modeling of plasma reactions and quantitative analysis of OES. • Interaction mechanism of plasma species and radicals was unveiled. • Synergy rules for plasma and thermal processes have been preliminarily obtained. Plasma-enhanced reforming has been widely studied as an efficient technology for online tar removal. By combining reforming experiments with kinetic modeling and in-situ optical emission spectrometry (OES) analysis, interaction mechanism and coupling rules of plasma/thermal reactions during plasma-assisted steam reforming of toluene were well explored in this study. A chemistry model was innovatively developed for plasma-assisted steam reforming of toluene, and predicted experimental results under different operations conditions with superb agreements. The rate of production and sensitivity analysis implied that OH, H and N 2 * mainly contributed to primary toluene conversion, while the electronic attachment dissociation of H 2 O, H addition onto benzene ring and benzyl oxidation by OH were the most enhancing-sensitive reactions. Resultantly, toluene conversion was greatly increased with steam addition before Vf H2O = 10 %, but after which Vf H2O increase deteriorated the reforming performance due to the inhibition of E-N 2 collision by high Vf H2O. As temperature increased, plasma and thermal synergistically promoted reforming performance before 300 °C, at which > 60 % toluene was converted into small molecules such as CO, H 2 and C 2 H 2, with yields of 23.6 %, 9.4 % and 16.3 % correspondingly at 12 kJ/L, but further temperature increase would not benefit due to the reduced discharge field strength at higher temperatures, being confirmed by the decreased relative intensity of OH, CN feature bands on OES. It was initially proposed that non-thermal plasma governed the reforming process at T < 300 °C, and thermal reactions predominated at T > 500 °C after a transition region (300 ∼ 500 °C). Increase of input energy caused higher discharge field strength, promoted the electronic collision ionization or dissociation of N 2 and H 2 O, thus enhanced toluene conversion and gas yields. A detailed reaction pathway has also been clarified. [ABSTRACT FROM AUTHOR]

[Display omitted] • Judd-Ofelt intensity parameters of phosphors are evaluated from absorption spectra. • The radiative parameters are determined using emission spectra and exhibits high σ e, σ e × Δλ eff , σ e × τ R and β. • The CIE, CCT and CRI values manifest the efficient application of phosphor in LEDs and indoor lighting. • The sensitivity values estimated using different spectral modes demonstrate the thermo-sensor application of phosphor. • The thermochromic study displays the safety sign marking application of phosphor. LiCa 2 Mg 2 V 3 O 12 :Sm3+ phosphors have been prepared by solid state method and analysed by X-ray diffraction, EDX-elemental mapping, UV–VIS-NIR spectroscopy, photoluminescence (PL) and temperature dependent photoluminescence (TDPL). The absorption spectra analysis using Judd-Ofelt theory provides the intensity parameters and manifest the covalent nature of Sm-O bond. The PL spectra monitored at 338 nm excitation exhibits emission peaks of Sm3+ at 567, 617 and 651 nm in addition to the broad band emission of LiCa 2 Mg 2 V 3 O 12 host. The Commision Internationale deL'Eclairage (CIE) coordinates, correlated color temperature (CCT) and color rendering index (CRI) values elucidate the efficient yellow emission of phosphors. The radiative parameters are evaluated and have outrageous branching ratio and cross section that aids in visible laser applications. The optical thermometry of phosphor is carried out by utilizing FIR method through selecting spectral modes 6H 5/2 /VO 4 3-, 6H 7/2 /VO 4 3- and 6H 9/2 / VO 4 3-. The mode 6H 9/2 / VO 4 3- have higher absolute sensitivity (S a) and relative sensitivity (S r) values of 0.4418 K−1 and 1.6079% K−1. The temperature resolution of modes are 0.1633, 0.1677 and 0.1563 K respectively. The thermochromic study reveals the high chromaticity shift (Δs = 0.1869) of phosphor and the S a (x) and S r (x) values evaluated based on CIE coordinates are 0.0011 K−1 and 0.2407% K−1 respectively. The PL and TDPL characteristics of prepared phosphor suggest that it have multifunctional application in the fields of lasers, thermo-sensors, thermochromic displays and LEDs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two molecular spectroscopic techniques were used to predict TVB-N content in salmon. • 2D-COS was proposed to select the spectral feature variables of NIR and Raman spectroscopy. • The order of mainly chemical information and molecular changes were determined. • The low-level data fusion of NIR and Raman spectra produced good prediction results. Total volatile basic nitrogen (TVB-N) serves as a crucial indicator for evaluating the freshness of salmon. This study aimed to achieve accurate and non-destructive prediction of TVB-N content in salmon fillets stored in multiple temperature settings (−20, 0, −4, 20 °C, and dynamic temperature) using near-infrared (NIR) and Raman spectroscopy. A partial least square support vector machine (LSSVM) regression model was established through the integration of NIR and Raman spectral data using low-level data fusion (LLDF) and mid-level data fusion (MLDF) strategies. Notably, compared to a single spectrum analysis, the LLDF approach provided the most accurate prediction model, achieving an R2 P of 0.910 and an RMSEP of 1.922 mg/100 g. Furthermore, MLDF models based on 2D-COS and VIP achieved R2 P values of 0.885 and 0.906, respectively. These findings demonstrated the effectiveness of the proposed method for precise quantitative detection of salmon TVB-N, laying a technical foundation for the exploration of similar approaches in the study of other meat products. This approach has the potential to assess and monitor the freshness of seafood, ensuring consumer safety and enhancing product quality. [ABSTRACT FROM AUTHOR]

Natural gas (NG) has been proposed as a bridging fuel between fossil and renewable energy sources, playing a significant role in the decarbonization of the energy sector. Its commercial value and the integrity of the NG infrastructure depend on the NG physical properties, which are strongly related to its composition. Thus, the development of low-cost and reliable analytical methods for composition analysis of NG can enable a more efficient operation. Recently, we showed that high-pressure (HP) benchtop 1H NMR spectroscopy combined with indirect hard modelling (IHM) is an efficient and low-cost method for composition quantification of NG. The current work extends this methodology by introducing and testing novel experimental strategies for increasing the reliability and accuracy of the method. This new approach includes the use of a recently published high-pressure tube design and single-scan acquisition combined with novel quality control parameters to obtain highly reproducible peak shape 1H NMR spectra over long periods. The proposed methodology tested on binary, ternary, and more complex mixtures at 200 bar and 160 bar gives compositions in excellent agreement with the vendor certificates. [Display omitted] • Novel experimental approach to obtain high-pressure multi-scan 1H NMR spectra. • Novel quality control parameters to select reproducible high-quality 1H NMR spectra. • New method to acquire the NMR spectra of higher-order hydrocarbons. • Indirect hard model developed at 200 bar is transferable to 160 bar. • NMR composition and physical properties in agreement with the vendor certificates. [ABSTRACT FROM AUTHOR]

As a representative local medicinal herb produced in China, Vladimiriae Radix (VR) has been proven to exert hepatoprotective and choleretic effects, with particular therapeutic efficacy in cholestatic liver injury (CLI), as demonstrated by the VR extract (VRE). However, the quality markers (Q-markers) of VRE for the treatment of CLI remain unclear. A new strategy based on the core element of "efficacy" was proposed, using a combination of spectrum-effect relationship, pharmacokinetics, and molecular docking methods to select and confirm Q-markers of VRE. First, the HPLC fingerprinting of 10 batches of VRE was studied, and the in vivo pharmacological index of anti-CLI in rats was determined. The spectrum-effect relationship was utilized as a screening method to identify the Q-markers of VRE. Secondly, Q-markers were used as VRE pharmacokinetic markers to measure their concentrations in normal and CLI rat plasma, and to analyze their disposition. Finally, molecular docking was utilized to predict the potential interaction between the identified Q-markers and crucial targets of CLI. The fingerprints of 10 batches of VRE was established. The in vivo pharmacological evaluation of rats showed that VRE had a significant therapeutic effect on CLI. The spectrum-effect correlation analysis showed that costunolide (COS) and dehydrocostus lactone (DEH) were the Q-markers of VRE anti-CLI. The pharmacokinetic results showed that AUC (0-t) , C max , CL Z/F , and V Z/F of COS and DEH in CLI rats had significant differences (P < 0.01). They were effectively absorbed into the blood plasma of CLI rats, ensuring ideal bioavailability, and confirming their role as Q-markers. Molecular docking results showed that COS, DEH had good affinity with key targets (FXR, CAR, PXR, MAPK, TGR5, NRF2) for CLI treatment (Binding energy < −4.52 kcal mol−1), further verifying the correctness of Q-marker selection. In this study, through the combination of experimental and theoretical approaches from the aspects of pharmacodynamic expression, in vivo process rules, and interaction force prediction, the therapeutic effect of VRE and Q-markers (COS、DEH) were elucidated. Furthermore, a new idea based on the principle of "efficacy" was successfully proposed for screening and evaluating Q-markers. [Display omitted] [ABSTRACT FROM AUTHOR]