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A high-resolution absorption spectrum of the S1–S0 transition of free-base phthalocyanine was observed and analyzed with improved reliability. The spectrum, with a partially resolved rotational structure, was obtained by using the buffer-gas cooling technique and a single-mode tunable laser. Our new analysis reveals that the S 1 ← S 0 0 0 0 band belongs to the a-type transition, where the electronic transition moment aligns parallel to the NH–HN direction, allowing the assignment of the S1 state to 1B3u. These results agree with a prior study using supersonic expansion and are well supported by theoretical calculations. Interestingly, the rotational constant B in the S1 state, which is often smaller than that in the ground state for typical molecules, was found to be slightly larger than that in the S01Ag state. This suggests a change in the character of π bonds with the electronic excitation. [ABSTRACT FROM AUTHOR]

It is important to understand the dynamics of red blood cells (RBCs) in blood flow. This requires the formulation of coarse-grained RBC models that reproduce the hydrodynamic properties of blood accurately. One of the models that successfully reproduces the rheology and morphology of blood has been proposed by Fedosov et al. [Comput. Methods Appl. Mech. Eng. 199, 1937–1948 (2010)]. The proposed RBC model contains several parameters whose values are determined by either various experiments or physical requirements. In this study, we developed a new method of determining parameter values precisely from the fluctuations of the RBC membrane. Specifically, we studied the relationship between the spectra of the fluctuations and model parameters. Characteristic peaks were observed in the spectra, whose peak frequencies were dependent on the parameter values. In addition, we investigated the spectra of the radius of gyration. We identified the peaks originating from the spring potential and the volume-conserving potential appearing in the spectra. These results lead to the precise experimental determination of the parameters used in the RBC model. [ABSTRACT FROM AUTHOR]

Lipids play crucial roles in many biological processes. Mapping spatial distributions and examining the metabolic dynamics of different lipid subtypes in cells and tissues are critical to better understanding their roles in aging and diseases. Commonly used imaging methods (such as mass spectrometry-based, fluorescence labeling, conventional optical imaging) can disrupt the native environment of cells/tissues, have limited spatial or spectral resolution, or cannot distinguish different lipid subtypes. Here we present a hyperspectral imaging platform that integrates a Penalized Reference Matching algorithm with Stimulated Raman Scattering (PRM-SRS) microscopy. Using this platform, we visualize and identify high density lipoprotein particles in human kidney, a high cholesterol to phosphatidylethanolamine ratio inside granule cells of mouse hippocampus, and subcellular distributions of sphingosine and cardiolipin in human brain. Our PRM-SRS displays unique advantages of enhanced chemical specificity, subcellular resolution, and fast data processing in distinguishing lipid subtypes in different organs and species.

SignificanceMeasuring hemodynamic function is crucial for health assessment. Optical signals provide relative hemoglobin concentration changes, but absolute measurements require costly, bulky technology. Speckleplethysmography (SPG) uses coherent light to detect speckle fluctuations. Combining SPG with multispectral measurements may provide important physiological information on blood flow and absolute hemoglobin concentration.AimTo develop an affordable optical technology to measure tissue absorption, scattering, hemoglobin concentrations, tissue oxygen saturation (StO2), and blood flow.ApproachWe integrated reflectance spectroscopy and laser speckle imaging to create coherent spatial imaging (CSI). CSI was validated against spatial frequency domain imaging (SFDI) using phantom-based measurements. In vivo arterial and venous occlusion experiments compared CSI with diffuse optical spectroscopy/diffuse correlation spectroscopy (DOS/DCS) measurements.ResultsCSI and SFDI agreed on tissue absorption and scattering in phantom tests. CSI and DOS/DCS showed similar trends and agreement in arterial occlusion results. During venous occlusion, both uncorrected and corrected blood flow decreased with increasing pressure, with an ∼200% difference in overall blood flow decrease between the methods. CSI and DOS/DCS data showed expected hemoglobin concentrations, StO2, and blood flow trends.ConclusionsCSI provides affordable and comprehensive hemodynamic information. It can potentially detect dysfunction and improve measurements, such as blood pressure, SpO2, and metabolism.

The study aimed to develop a potential biomaterial for neuroregeneration by the electrospinning of the biocompatible polymer polyvinylidene fluoride (PVDF) with innovative functionalized boron nitride quantum dots (F-BNQDs) synthesized via green chemistry using the amino acid taurine as a functionalization. The F-BNQDs were characterized and were found to be 16-21 nm in diameter, showed good photoluminescent characteristics, and their elemental composition was confirmed by x-ray photoelectron spectroscopy, Fourier-transform infrared (FTIR), and ultraviolet spectroscopy. The PVDF with F-BNQDs was prepared at three different concentrations, and the resulting electrospun fibers were characterized by scanning electron microscopy, FTIR, thermogravimetric analysis, contact angle, biodegradation, water uptake, Schwann cell cytotoxicity, and cell behavior studies. The results of the study showed that the addition of F-BNQDs to PVDF resulted in enhanced mechanical properties, decreased contact angle, increased degradability, and water uptake. The lactate dehydrogenase assay revealed that 5% BN-PVDF had the lowest cytotoxicity. Fluroscent 4',6-diamidino-2-phenylindole (DAPI) staining showed that the increase in F-BNQD concentration up to 5% BN-PVDF enhanced cell behavior on the electrospun fibers. Therefore, the study concluded that 5% BN-PVDF would be suitable for further testing as a potential biomaterial for neuroregeneration in vivo. Highlights * Functionalized boron nitride quantum dots (F-BNQDs) were prepared using amino acid taurine. * The F-BNQDs were characterized and electrospun with polyvinylidene fluoride (PVDF). * The incorporation of F-BNQDs to PVDF has enhanced its physicochemical properties. * All samples showed a single [beta]phase PVDF. * Schwann cells showed excellent compatibility and cell adhesion on F-BNQDs/PVDF. KEYWORDS electrospinning, functionalized boron nitride quantum dots, PVDF, Schwann cells, taurine, 1 | INTRODUCTION Peripheral nerve injuries have the potential to cause total transection of the nerve, necessitating surgical intervention to enable the regrowth of axons from the injured site to [...]

As one of the first renowned women spectroscopists, Craver broke down barriers in the field and is recognized for her work compiling reference libraries of spectra that set the foundation for modern infrared (IR) spectroscopy., When Stephen Smith brought his wife home to meet his mother, Clara Craver, the first thing she noticed was the decor. Craver's house was adorned with reproduc tions of paintings […]

Dynamic multiple light scattering (DMLS) has found numerous applications, including soft matter physics and biomedical optics. Yet biological tissues may have complex internal geometries, presenting a challenge for noninvasive measurements. Deciphering laminar dynamics is crucial to accurately interpret tissue or organ physiology. Seminal DMLS work noted that one can probe deeper layers indirectly by analyzing light fluctuations on shorter time scales. Recent technologies have enabled probing deeper layers directly by analyzing fluctuations at longer path lengths. The following question arises: are the indirect and direct approaches synergistic or redundant? Here, by adding an optical switch to path-length-filtered interferometric diffusing wave spectroscopy, we experimentally address this question in the context of a forearm occlusion study. We find that both approaches afford better distinction of light scattering dynamics in layered tissues than either approach alone. This motivates further development of methods that integrate both decorrelation time scale and light path length to probe layered tissues.

With the recent advances in serial crystallography methods at both synchrotron and X-ray free electron laser sources, more details of intermediate or transient states of the catalytic reactions are being revealed structurally. These structural studies of reaction dynamics drive the need for on-line in crystallo spectroscopy methods to complement the crystallography experiment. The recent applications of combined spectroscopy and crystallography methods enable on-line determination of in crystallo reaction kinetics and structures of catalytic intermediates, sample integrity, and radiation-induced sample modifications, if any, as well as heterogeneity of crystals from different preparations or sample batches. This review describes different modes of spectroscopy that are combined with the crystallography experiment at both synchrotron and X-ray free-electron laser facilities, and the complementary information that each method can provide to facilitate the structural study of enzyme catalysis and protein dynamics.

We investigated the effect of the sheath around the probe tips on the transmission spectrum of a cutoff probe using an electromagnetic simulation and a circuit model. Our results show that the width of the sheath can change the transmission spectrum, which can affect the absolute value of the electron density. In a real-world cutoff probe structure, this effect may become apparent in a low-density plasma or when a high bias voltage is applied to the plasma. The key factor is capacitance, which contains the sheath component. In the case of a low-density plasma, the change in the sheath capacitance of the sheath region contributes to the shift in the resonant frequency. For thick sheath widths, at least a 5% discrepancy can occur between the actual plasma frequency and the measurement owing to variations in the capacitance, particularly the sheath components surrounding the probe. We expect that this study will facilitate reduction in the measurement error and uncertainty in microwave cutoff probe measurements, particularly when applied to low-density plasma measurements. [ABSTRACT FROM AUTHOR]

To study the initiation and development of interfacial electrical damage in multi-layer dielectrics, an aging test of 3-layer polyimide films was conducted under pulsed voltage with a repetitive frequency of 500 Hz and a maximal amplitude of 30 kV. The variation in the damage morphology with the number of applied pulses was analyzed by a statistical method. The circuit current and partial discharge at different aging stages was measured, and the Fourier transform infrared spectrum analysis results of the aged and unaged sample regions were compared. The results demonstrate that the partial discharge in the dielectric interface gap, which is unavoidable in manufacturing, is the main cause of damage. It initiates from the interface and grows into the interior of the dielectric with the application of pulses. When there are no macroscopic defects on dielectric films, damage presents a punctiform morphology. The damage process can be divided into the following three stages: surface roughening damage, steady growth stage of damage points, and pre-breakdown stage. Differing from dielectrics without macroscopic defects, dielectrics with original void defects present transverse dendritic damage channels that initiate from the edge of the defect. [ABSTRACT FROM AUTHOR]

A flat-cutoff sensor installed on the chamber wall or chuck allows precise measurement of the plasma density in real time, even with a wafer placed on the sensor. However, a few studies have been conducted on the measurement characteristics in an environment where a wafer containing a metal layer is placed on a sensor. In this study, we investigated the effect of wafers containing metal layers on flat-cutoff sensor measurements using circuit models and experiments. The metal layer in the wafer shifts the cutoff frequency up to four times higher, and the degree of shift depends on the plasma density. The relationship between the shift in the cutoff frequency and plasma density can be interpreted as the ratio of the plasma inductance to that of the metal layer from the circuit model of the flat-cutoff sensor. The calculation results were verified experimentally using wafers containing Al and Ti metal layers. As a result, measurement was found to be possible even when a wafer containing a metal layer was placed on a flat-cutoff sensor, and these results can improve the measurement accuracy of the flat-cutoff sensor for the real-time plasma measurement. [ABSTRACT FROM AUTHOR]

Wound healing is a topic of significant interest in current times, owing to the escalating incidence of chronic diseases associated with impaired healing, as well as the growing number of elderly individuals within the population. Amongst the various approaches for fabrication of wound healing dressings, the utilization of selenium-based nanoparticles has garnered considerable attention due to selenium's numerous advantages, including antioxidant, antiviral, antibacterial, and antifungal activities. With this perspective, we focused on the fabrication and characterization of hydrogels incorporated with selenium nanoparticles (SeNPs). In this work, we have developed a microwave-assisted hydrothermal synthesis strategy for synthesis of the SeNPs that employ non-toxic precursors, thereby reducing the risk of environmental toxicity and providing a cost-effective alternative to conventional chemical and hydrothermal methods. Subsequently, we have successfully incorporated SeNPs into hyaluronic acid methacrylate/gelatin methacrylate-based hydrogels. Hyaluronic acid and gelatin are selected to support the healing process further, and these polymers are methacrylated in order to further control mechanical properties of the hydrogel and improve the stability of the dressing. The nanoparticles and the nanoparticle-incorporated hydrogels were characterized by various techniques including Fourier transform infrared spectroscopy, UV-Vis spectroscopy, scanning electron microscopy, and dynamic light scattering instruments. Mechanical behaviors, swelling and degradation properties of the dressings were evaluated. Afterwards, we have conducted cell culture studies with SeNPs-loaded hydrogels to determine the efficacy of SeNPs in wound healing. According to experimental findings, in vitro scratch assay suggests that a hydrogel dressing containing SeNPs (HG-SeNp2) support the cell migration more compared to other samples incorporated with nanoparticles and to the control study at 24 h, and the wound closure percentage was found to be statistically significant compared with the control study. This dressing hold promise as effective wound dressings that can facilitate and expedite the process of wound healing. KEYWORDS gelatin methacrylate, green synthesis, hyaluronic acid methacrylate, hydrogel, microwave-assisted hydrothermal synthesis, selenium nanoparticles, wound healing, 1 | INTRODUCTION Wound care has emerged as a prominent research area in the current literature landscape. This interest can be attributed to the global rise in the elderly population [...]

We evaluate the effectiveness of early dark energy (EDE) in addressing the Hubble tension using the luminous red galaxy (LRG), quasar (QSO), and emission line galaxy (ELG) samples from the completed eBOSS survey. We perform cosmological parameter measurements based on full shape analysis of the power spectrum employing the effective field theory of large-scale structure (EFTofLSS). EDE is known to strongly suffer from volume projection effects, complicating cosmological constraints' interpretation. To quantify the volume projection effects within an EDE full shape analysis, we explore the impact of different prior choices on the nuisance parameters of EFTofLSS through an extensive mock study. We compare classical Gaussian priors to the non-informative Jeffreys prior, known to mitigate volume projection effects in ΛCDM. Our full shape analysis combines eBOSS and BOSS data with Planck , external Baryon Acoustic Oscillation (BAO), PantheonPlus, and SH0ES supernova data. EDE reduces the tension from 5.2σ to 3σ compared to ΛCDM, yielding |$H_0=71.73_{-0.86}^{+0.82}$| km s−1 Mpc−1 with |$f_\mathrm{EDE} = 0.1179_{-0.022}^{+0.025}$| (Gaussian priors) and |$H_0=72.03_{-0.87}^{+0.82}$| km s−1 Mpc−1 with |$f_\mathrm{EDE} = 0.1399_{-0.022}^{+0.023}$| (Jeffreys prior). Although the Hubble tension is mitigated compared to ΛCDM, the inclusion of eBOSS data amplifies the tension within EDE from 2σ to 3σ, in contrast to the full shape analysis of BOSS data with Planck , external BAO, PantheonPlus, and SH0ES. This highlights the significance of incorporating additional large-scale structure data in discussions concerning models aiming to resolve the Hubble tension. [ABSTRACT FROM AUTHOR]

The research investigates the validity of the complete quadratic combination (CQC) method. A new approach is proposed in order to consider the effect of modal correlation more accurately than the CQC method. Statistical analysis indicates that the error in the estimation of modal correlation could be reduced compared to the CQC method. This method is especially more accurate in higher frequency ratios where the role of interaction between modes in the seismic response is noticeable. Statistical analysis reveals that the proposed method is more precise, especially for far-field records. Meanwhile, the proposed method is not sensitive to different site classes. [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]

Single-walled carbon nanotubes (SWCNTs) show great potential for their application as cancer therapeutic nanodrugs, but the efficiency and mechanism of their accumulation in the cell, the modulation of cell activity, and the strong dependence of the results on the type of capping molecule still hinder the transfer of SWCNTs to the clinic. In the present study, we determined the mechanism and sequence of accumulation, distribution and type discrimination of SWCNTs in glioma cells by applying K-means clustering and principal component analysis (PCA) of Raman spectra of cells exposed to SWCNTs capped with either DNA or oligonucleotides (ON). Based on the specific biochemical information uncovered by PCA and further applied to K-means, we show that the accumulation of SWCNT–DNA occurs in two phases. The first phase involves the transport of SWCNT–DNA through vesicles and its redistribution in the cytoplasm, which is reflected in two SWCNT-related clusters. The second phase begins after 18 hours of interaction between cells and SWCNT–DNA. PCA shows the appearance of two SWCNT-associated PC loadings, reflected by the addition of a new cluster of SWCNTs with a narrowed and shifted G-peak in the spectra. It is caused by the loss of DNA capping and clumping of SWCNTs and triggered by the acidic conditions in autolysosomes resulting from the fusion of transport vesicles with lysosomes. SWCNTs penetrate all cellular compartments after 42–66 hours and lead to cell death. The clumped SWCNTs are released to the outside. In contrast, SWCNT–ON is hardly accumulated in glioma cells and after 72 hours of exposure to SWCNT–ON, the accumulation of SWCNTs corresponds to the first stage without reaching the second. PCA made it possible to separate the characteristics of cellular components against the high-intensity Raman signal from nanotubes and, thus, to propose the mechanism of accumulation and metabolism of nanomaterials in living cells without the use of additional research approaches. Our results elucidate the time dependence of the accumulation of SWCNTs on the capping molecule. We expect that our results can make an important contribution to the use of these nanomaterials in the clinic. [ABSTRACT FROM AUTHOR]

Although the rapid expansion of urban rail transit offers convenience to citizens, the issue of subway vibration cannot be overlooked. This study investigates the spatial distribution characteristics of vibration in the Fayuan Temple historic and cultural reserve. It involves using a V001 magnetoelectric acceleration sensor capable of monitoring low amplitudes with a sensitivity of 0.298 V/(m/s2), a measuring range of up to 20 m/s2, and a frequency range span from 0.5 to 100 Hz for in situ testing, analyzing the law of vibration propagation in this area, evaluating the impact on buildings, and determining the vibration reduction scheme. The reserve is divided into three zones based on the vertical vibration level measured during the in situ test as follows: severely excessive, generally excessive, and non-excessive vibration. Furthermore, the research develops a dynamic coupling model of vehicle–track–tunnel–stratum–structure to verify the damping effect of the wire spring floating plate track and periodic pile row. It compares the characteristics of three vibration reduction schemes, namely, internal vibration reduction reconstruction, periodic pile row, and anti-vibration reinforcement or reconstruction of buildings, proposing a comprehensive solution. Considering the construction conditions, difficulty, cost, and other factors, a periodic pile row is recommended as the primary treatment measure. If necessary, anti-vibration reinforcement or reconstruction of buildings can serve as supplemental measures. [ABSTRACT FROM AUTHOR]

Although the potential of Raman Optical Activity (ROA) spectroscopy in the field of organic and inorganic materials research has been well demonstrated, its practical application is still limited. This work shows historical background, current state of the art and challenges of ROA spectroscopy facing scientists today. Expectations and development prospects for the coming years are also discussed. Efforts have already been made to improve but also to properly interpret the ROA signal when the ROA technique is combined with other spectroscopies (i.e., ROA/Electronic Circular Dichroism and ROA/Circularly Polarized Luminescence). The paper shows how to intensify the ROA effect to shorten the spectrum accumulation time, control possible artefacts and support the analysis of ROA spectra with actual and new theoretical approaches. However, the challenge is to increase the interest in this technique among the academic community, develop reliable protocols and adapt them for practical use. National and international research networks can significantly contribute to the growth of methodologies and standardization in areas in which the ROA has so far been little used. This paper presents a perspective vision for the future progress of ROA alongside other chiroptical methods. [ABSTRACT FROM AUTHOR]

Compared with Group VIB transition metal dichalcogenides (TMDs), Group IVB TMDs, specifically ZrX2, have exhibited superior carrier mobility, rendering them highly promising for developing innovative electron devices. The application of high‐pressure has been identified as an effective approach for altering the physical properties of TMDs by manipulating their lattice and electronic structures. This subject has attracted considerable attention within the scientific community. In this investigation, in situ high‐pressure Raman scattering and UV‐visible absorption spectra analysis are conducted to examine the lattice and electronic structural changes in multilayer ZrS2. Raman spectroscopy analysis reveals two phase transitions occurring at 3.65 and 10.95 GPa. Concurrently, the optical absorption findings reveal a distinct transformation in both the optical energy gap and Urbach energy at 3.34 GPa, highlighting the accompanying lattice and electronic structural changes in ZrS2 under high‐pressure. Moreover, these lattice and electronic structural changes are found to be irreversible, indicating the potential utility of compressed ZrS2 in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Seismic images are essential for understanding the subsurface geological structure and resource distribution. However, the accuracy and certainty of geological analysis using seismic images are limited by the resolution and signal-to-noise ratio. Simultaneously improving resolution and suppressing random noise with traditional methods can be quite challenging. This research proposes a new approach called SeisGAN which leverages a generative adversarial network to address the challenge at hand. Due to the lack of high-resolution noiseless and low-resolution noisy seismic data, stochastic parameter control is employed to simulate a vast range of diverse, paired seismic data for SeisGAN training. The results on the synthetic dataset demonstrate that the proposed method is effective in enhancing the resolution and suppressing the random noise in the original images. Spectrum analysis shows that the proposed method increases the bandwidth of the original data, primarily at high frequencies. Ablation experiments reveal that, under similar conditions, SeisGAN outperforms traditional convolutional neural networks. Incorporating the VGG loss in the generator loss function improves the model's ability to recover high-frequency details. The application of the technique on two publicly available field seismic datasets indicates SeisGAN's excellent generalizability, despite being trained only on synthetic seismic data. Compared with bicubic interpolation and traditional noise suppression and resolution enhancement methods, SeisGAN is capable of effectively suppressing the random noise and enhancing the dominant frequency of field seismic data, making it easier to identify adjacent thin layers and fault features, even for small-scale faults. The zoomed images are clearer and easier to interpret. Furthermore, an example of automatic machine fault identification demonstrates the significant contribution of the SeisGAN-enhanced image to accurate fault recognition. [ABSTRACT FROM AUTHOR]

Tyrosinase inhibitors can reduce melanin production for skin whitening, but some existing products may harm the skin. This study discovered six compounds that inhibit tyrosinase in the mushroom Agaricus bisporus by over 50%. Compound 11 displayed strong inhibition (92.2% and 86.7%) for L-tyrosine and L-DOPA substrates, while compound 13 showed high inhibition (96.0% and 62.0%) for both substrates. Molecular docking simulations revealed compounds 11 and 13 bind at the allosteric site of the enzyme. Xanthone derivatives, based on these findings, hold potential as safe skin whitening agents and for pigmentation-related diseases in the cosmetic industry. [ABSTRACT FROM AUTHOR]

New dammarane-type triterpenoid saponin, named 22(R)-notoginsenoside Ab1 (1), together with thirteen known dammarane-type triterpenoid saponins (2-14) was isolated from the EtOH extract of black ginseng and their structures were elucidated on the basis of one- and two-dimensional NMR (including 1H-NMR, 13C-NMR, HSQC, HMBC, ROESY) and calculated ECD. Among them, compounds 1-2 and 6-8 were isolated for the first time from ginseng and black ginseng. Besides, the absolute structure of 22(R)- and 22(S)- notoginsenoside Ab1 were distinguished by ECD for the first time. [ABSTRACT FROM AUTHOR]

In order to further clarify the shale oil accumulation period of the Chang 7 member of the Mesozoic Triassic Yanchang Formation in the Zhijing-Ansai area of the central Ordos Basin, Using fluid inclusion petrography analysis, microscopic temperature measurement, salinity analysis and fluorescence spectrum analysis methods, combined with the burial history-thermal history recovery in the area, the oil and gas accumulation period of the Chang 7 member of the Yanchang Formation in the Zhijing-Ansai area was comprehensively analyzed. Sixteen shale oil reservoir samples of the Mesozoic Triassic Yanchang Formation in seven typical wells in the study area were selected.The results show that the fluid inclusions in the Chang 7 member of Yanchang Formation can be divided into two stages. The first stage inclusions mainly develop liquid hydrocarbon inclusions and a large number of associated brine inclusions, which are mainly beaded in fracture-filled quartz and fracture-filled calcite. The fluorescence color is blue and blue-green, and the homogenization temperature of the associated brine inclusions is between 90–110°C. The second stage inclusions are mainly gas-liquid two-phase hydrocarbon inclusions, gas inclusions and asphalt inclusions. Most of them are distributed in the fracture-filled quartz, and the temperature of the associated brine inclusions is between 120–130°C. Fluid inclusions in Chang 7 member of the Yanchang Formation can be divided into two stages. The CO2 inclusions and high temperature inclusions in the Chang 7 member of the Yanchang Formation are mainly derived from deep volcanic activity in the crust. [ABSTRACT FROM AUTHOR]

Rank‐reduction‐based simultaneous random noise attenuation and three‐dimensional seismic‐data interpolation has recently become a hot topic in reflection seismology. However, the rank of traditional methods is fixed without considering the variation of signal‐to‐noise ratio on different frequency components, leading to serious residual noise and further affecting the following processing and interpretation tasks. In addition, traditional methods also heavily rely on the application of singular value decomposition technique for rank reduction, which is proven to be computationally expensive for large‐scale data. Thus, a fast‐adaptive rank‐reduction method is proposed in this study. First, the information entropy theory is introduced to adaptively select the optimal rank at various frequencies by calculating the increment of singular entropy. Second, we propose a fast Random Block Krylov algorithm and a subspace multiplexing technique to replace the singular value decomposition algorithm used in traditional methods. The proposed method can significantly improve computational efficiency and yield better seismic‐data reconstruction performance than traditional methods. Applications of the proposed approach on both synthetic and field seismic data demonstrate its superior performance over a well‐known rank‐reduction‐based method, that is the random multi‐channel singular spectrum analysis, in terms of recovered signal‐to‐noise ratio and visual view. [ABSTRACT FROM AUTHOR]

Ocean bottom seismometer data usually contain a large amount of random noise, which seriously reduces the signal‐to‐noise ratio of the data and affects subsequent imaging. Hence, random noise attenuation is one of the most essential steps in ocean bottom seismometer data processing. In this paper, a novel approach is proposed to attenuate the marine seismic random noise of ocean bottom seismometers based on a six‐dense‐layer denoising autoencoder. We input the t−x$t-x$ domain data into the denoising autoencoder, the encoder compresses the signal and noise and extracts the main features and the decoder finally reconstructs the denoised data with the same dimension as the input. In this approach, because few raw labelled examples are available, we first constructed the pretraining, training and test data sets by patch processing. Then, we pretrained the encoder based on clean synthetic seismic data through unsupervised learning and pretrained the decoder based on noisy synthetic seismic data through supervised learning. Next, the pretrained model was fine‐tuned with the encoder–decoder on a raw seismic data set in an unsupervised manner. Finally, we used the model to attenuate the random noise in raw ocean bottom seismometer data for testing. Synthetic and raw examples are used to compare the f−x$f-x$ deconvolution, multichannel singular spectrum analysis, deep denoising autoencoder and substep deep denoising autoencoder approaches. Experimental tests demonstrate that the proposed method has higher processing efficiency and precision. [ABSTRACT FROM AUTHOR]

Analysis of the spectrum of inelastically scattered electrons in XPS has been used for decades to determine the structure of materials on the nanoscale. Using the higher photon energies available in HAXPES, the method was recently shown to determine structures rather accurately with a more than 100 nm probing depth. In this paper, these HAXPES applications are briefly reviewed. Only two parameters are required for the analysis, namely, the inelastic mean free path and the cross section for inelastic electron scattering. We also discuss in detail how these parameters are best selected. [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]

Hailstorms, while fascinating from a meteorological perspective, pose significant risks to communities, agriculture, and infrastructure. In regions such as the Central Andes of Peru, the characteristics and frequency of these extreme weather events remain largely uncharted. This study fills this gap by investigating the historical frequency and vertical structure of hailstorms in this region. We analyzed historical hailstorm records dating back to 1958 alongside 4 years of observations (2017–2021) from the Parsivel2 disdrometer and a cloud-profiling radar MIRA35c. Our findings indicate a trend of decreasing hail frequency (- 0.5 events per decade). However, the p value of 0.07 suggests the need for further investigation, particularly in relation to environmental changes and reporting methods. The results show that hailstorms predominantly occur during the austral summer months, with peak frequency in December, and are most common during the afternoon and early evening hours. The analysis of radar variables such as reflectivity, radial velocity, spectral width, and linear depolarization ratio (LDR) reveals distinct vertical profiles for hail events. Two case studies highlight the diversity in the radar measurements of hailstorms, underscoring the complexity of accurate hail detection. This study suggests the need for refining the Parsivel2 algorithm and further understanding its classification of hydrometeors. Additionally, the limitations of conventional radar variables for hail detection are discussed, recommending the use of LDR and Doppler spectrum analysis for future research. Our findings lay the groundwork for the development of more efficient hail detection algorithms and improved understanding of hailstorms in the Central Andes of Peru. [ABSTRACT FROM AUTHOR]

The proposed "Guanlan" ocean science satellite, led by China's Laoshan Laboratory, includes an interferometric radar altimeter (IRA) as a key payload. As an integral part of its development, an airborne IRA experiment was conducted on 6 November 2021, with a flight path of approximately 90 km in the South China Sea. This study investigates the IRA's ability to observe ocean sea surface height (SSH) across scales ranging from meters to mesoscale. The sea surface height anomaly (SSHA) of the IRA is aligned with the SSHA of the AVISO at scales greater than 30 km, but also demonstrates the ability to capture small-scale SSHA changes in two dimensions. We analyzed wavenumber spectra of SSHA obtained from the airborne IRA, ICESat-2, and SARAL/AltiKa satellite for this region. The results show a good agreement in power spectral density (PSD) levels between ICESat-2, SARAL/AltiKa and IRA at scales larger than 30 km. Within the submesoscale range of 1–10 km, the IRA SSHA spectrum exhibits a distinctly negative slope and the lowest energy level. The minimum PSD level of the IRA fell in the range of 10−4–10−3 m2/cycle/km, at scales around 1 km, which is more than an order of magnitude lower than that of ICESat-2, forming a spectral gap that is in agreement with the theoretical expectation. Furthermore, IRA-derived wave direction and significant wave height matched well with the MFWAM wave data. The results of this study underscore the considerable potential of airborne IRA in capturing SSHA across a range of scales, from oceanic waves to submesoscale. [ABSTRACT FROM AUTHOR]

The overall gain of a scintillation detector is temperature-dependent, leading to a drift in the measured gamma energy spectrum with changes in temperature. To mitigate this effect, a temperature drift correction is essential prior to conducting gamma spectrum analysis. In this study, the detector gain ratio is determined by comparing the positions of the same background peak across different spectra. Subsequently, the original spectrum is adjusted accordingly to obtain a gamma spectrum free from temperature drift. Experimental results demonstrate that after implementing this correction, the relative deviation of the 57Co characteristic peak positions in the gamma spectrum measured by the NaI(Tl) detector is reduced from 18.64% to 0.91%. Furthermore, by performing energy calibration beforehand, the characteristic peak position can be utilized for secondary correction, further minimizing temperature drift. Our findings indicate that the relative deviation of the 22Na characteristic peak positions was reduced, respectively, to 0.51% and 0.46% through secondary correction. This approach, which utilizes the background peak for correction, avoids the need for additional radioactivity or circuitry and effectively mitigates peak drift. Overall, this method holds significant implications for enhancing the accuracy of gamma spectrum analysis. [ABSTRACT FROM AUTHOR]

The characteristic frequency of a rub-impact fault is usually very complex and may contain higher harmonics and subharmonics. Due to the uncertainty of harmonic components and the complexity of signal-to-noise ratio (SNR) operation, the general scale transformation stochastic resonance (GSTSR) has certain limitations in the identification of rub-impact faults. To solve this problem, the paper starts with complexity and proposes a rub-impact fault identification method combining a swarm intelligence optimized algorithm (SIOA) with Hjorth parameters and GSTSR. The complexity of vibration signals will change greatly before and after rub-impact faults. The complexity parameter in Hjorth parameters can effectively embody the complexity of signals and is invulnerable to noise interference. Therefore, the complexity parameter in the Hjorth parameters is taken as the objective function of SIOA and combined with GSTSR. Vibration signals from cases are taken as input to adaptive stochastic resonant (ASR) systems, and the system parameters are adaptively and synchronously adjusted to realize the maximal resonant effect. Finally, the spectrum analysis of signals obtained from ASR is used to extract failure features and recognize faults in the rotor–stator rub-impact. The proposed method is verified by comparing it with other schemes under different SIOAs and different operating conditions. The result of the comparison shows that the complexity parameter of the Hjorth parameters can be taken as the objective function of SIOA to accurately identify the rub-impact fault. Meanwhile, the proposed method, compared with the method of taking SNR as an objective function, has a better effect on reducing time costs and strengthening fault characteristics. [ABSTRACT FROM AUTHOR]

A new technique for ex situ solid-state nuclear magnetic resonance imaging of polymeric films has been developed. This method uses the static magnetic field gradient generated by a water-cooled copper electromagnet. The imaging process involves scanning the sample in the plane of the film under a static magnetic field gradient. Two-dimensional (2D) 19F MRI measurements are attempted, where the fast Fourier transform (FFT) spectra of the second half of a Hahn echo peak is used for the depth (X-axis) direction, and the sample film is mechanically moved for the Y-axis, which is in-plane with respect to the film surface and normal to the inter-magnetic-pole line (Z-axis). The sample is a poly(tetrafluoroethylene) [PTFE] film with carved stripes on its surface. Furthermore, three-dimensional (3D) measurements of the film surface and thickness orientations were also performed for an analogous PTFE film. For 2D profiling on the film surface, 2D sample-moving was used. For depth profiling, FFT spectrum analysis was undertaken for each voxel situated at a specific (Y, Z) coordinate within the film. As a result, a 3D image of the sample and its corresponding geometry were obtained, although the scanning area was restricted to a part of the sample. Finally, numerical simulations of the spatial distribution of the static magnetic field were performed to confirm the validity of the present method. [ABSTRACT FROM AUTHOR]

BACKGROUND: Global plastic use has consistently increased over the past century with several different types of plastics now being produced. Much of these plastics end up in oceans or landfills leading to a substantial accumulation of plastics in the environment. Plastic debris slowly degrades into microplastics (MPs) that can ultimately be inhaled or ingested by both animals and humans. A growing body of evidence indicates that MPs can cross the gut barrier and enter into the lymphatic and systemic circulation leading to accumulation in tissues such as the lungs, liver, kidney, and brain. The impacts of mixed MPs exposure on tissue function through metabolism remains largely unexplored. OBJECTIVES: This study aims to investigate the impacts of polymer microspheres on tissue metabolism in mice by assessing the microspheres ability to translocate across the gut barrier and enter into systemic circulation. Specifically, we wanted to examine microsphere accumulation in different organ systems, identify concentration-dependent metabolic changes, and evaluate the effects of mixed microsphere exposures on health outcomes. METHODS: To investigate the impact of ingested microspheres on target metabolic pathways, mice were exposed to either polystyrene (5 μm) microspheres or a mixture of polymer microspheres consisting of polystyrene (5 μm), polyethylene (1–4 μm), and the biodegradability and biocompatible plastic, poly-(lactic-co-glycolic acid) (5 μm). Exposures were performed twice a week for 4 weeks at a concentration of either 0, 2, or 4 mg/week via oral gastric gavage. Tissues were collected to examine microsphere ingress and changes in metabolites. RESULTS: In mice that ingested microspheres, we detected polystyrene microspheres in distant tissues including the brain, liver, and kidney. Additionally, we report on the metabolic differences that occurred in the colon, liver, and brain, which showed differential responses that were dependent on concentration and type of microsphere exposure. DISCUSSION: This study uses a mouse model to provide critical insight into the potential health implications of the pervasive issue of plastic pollution. These findings demonstrate that orally consumed polystyrene or mixed polymer microspheres can accumulate in tissues such as the brain, liver, and kidney. Furthermore, this study highlights concentration-dependent and polymer type-specific metabolic changes in the colon, liver, and brain after plastic microsphere exposure. These results underline the mobility within and between biological tissues of MPs after exposure and emphasize the importance of understanding their metabolic impact [ABSTRACT FROM AUTHOR]

Vibration signal analysis is an important means for bearing fault diagnosis. Affected by the vibration of other machine parts, external noise and the vibration transmission path, the impulses induced by a bearing defect in the measured vibrations are very weak. Blind deconvolution (BD) methods can counteract the effect of the transmission path and enhance the fault impulses. Most BD methods highlight fault features of the filtered signals by impulse-featured objective functions (OFs). However, residual noise in the filtered signals has not been well tackled. To overcome this problem, a fuzzy entropy-assisted deconvolution (FEAD) method is proposed. First, FEAD takes advantage of the high noise sensitivity of fuzzy entropy (FuzzyEn) and constructs a weighted FuzzyEn–kurtosis OF to enhance the fault impulses while suppressing noise interference. Then, the PSO algorithm is used to iteratively solve the optimal inverse deconvolution filter. Finally, envelope spectrum analysis is performed on the filtered signal to realize bearing fault diagnosis. The feasibility of FEAD was first verified by the bearing fault simulation signals at constant and variable speeds. The bearing test signals from Case Western Reserve University (CWRU), the railway wheelset and the test bench validated the good performance of FEAD in fault feature enhancement. A comparison with and quantitative results for the other state-of-the-art BD methods indicated the superiority of the proposed method. [ABSTRACT FROM AUTHOR]

The study presents a bioindication complex and a technology of the experiment based on a submersible digital holographic camera with advanced monitoring capabilities for the study of plankton and its behavioral characteristics in situ. Additional mechanical and software options expand the capabilities of the digital holographic camera, thus making it possible to adapt the depth of the holographing scene to the parameters of the plankton habitat, perform automatic registration of the "zero" frame and automatic calibration, and carry out natural experiments with plankton photostimulation. The paper considers the results of a long-term digital holographic experiment on the biotesting of the water area in Arctic latitudes. It shows additional possibilities arising during the spectral processing of long time series of plankton parameters obtained during monitoring measurements by a submersible digital holographic camera. In particular, information on the rhythmic components of the ecosystem and behavioral characteristics of plankton, which can be used as a marker of the ecosystem well-being disturbance, is thus obtained. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 has accumulated many mutations since its emergence in late 2019. Nucleotide substitutions leading to amino acid replacements constitute the primary material for natural selection. Insertions, deletions, and substitutions appear to be critical for coronavirus's macro- and microevolution. Understanding the molecular mechanisms of mutations in the mutational hotspots (positions, loci with recurrent mutations, and nucleotide context) is important for disentangling roles of mutagenesis and selection. In the SARS-CoV-2 genome, deletions and insertions are frequently associated with repetitive sequences, whereas C>U substitutions are often surrounded by nucleotides resembling the APOBEC mutable motifs. We describe various approaches to mutation spectra analyses, including the context features of RNAs that are likely to be involved in the generation of recurrent mutations. We also discuss the interplay between mutations and natural selection as a complex evolutionary trend. The substantial variability and complexity of pipelines for the reconstruction of mutations and the huge number of genomic sequences are major problems for the analyses of mutations in the SARS-CoV-2 genome. As a solution, we advocate for the development of a centralized database of predicted mutations, which needs to be updated on a regular basis. [ABSTRACT FROM AUTHOR]

The High Dam is one of the world's biggest embankments dams. Moreover, the new city of Aswan, which locates on the western side of the Nile River, is one of the cities that was established to overcome the growing population problem. Therefore, the detailed geophysical studies for the active faults are of more importance for assessing the seismic stability for both of them. Indeed, the emergency spillway fault was documented as a normal and inactive fault. While, a moderate earthquake (ML = 4.6) was recorded along this fault in 2010, about 4.5 km away from the Dam. Hence, its activity must be re-evaluated. The seismic activity along the fault and its extension has been studied. The seismicity distributions and the fault plane solution indicate normal faulting with a strike-slip component and shallow focal depth. Moreover, pore pressure and fluid diffusion play an essential role in fault activation process. On the other hand, the magnetic data for the research area was subjected to a detailed analysis. 2D spectrum analysis and 3D Euler deconvolution methods, were used to analyze and interpret the aeromagnetic anomaly data so as to better understand the tectonic framework of the study region. Finally, the integrated geophysical data delineate the trend of the emergency spillway fault which extends NW–SE. This fault could assist in updating the current seismic source model around the High Dam and new Aswan city for evaluating the seismic hazard for both of them. [ABSTRACT FROM AUTHOR]

Phytochemical investigation on cigar tobacco leaves led to four unknown sesquiterpenoids as well as nine reported ones. Among of them, 3-acetoxy-β-damascone was first found in tobacco leaves. All the structures were elucidated by intensive spectroscopic analyses and X-ray diffraction. The relationship between the newly isolates and known ones was tried to describe. [ABSTRACT FROM AUTHOR]

Use of small molecules as valuable drugs against diseases is still an indefinable purpose due to the lack of in-detail knowledge regarding proper bio-target identification, specificity aspects, mode-mechanism of binding and proper in vitro study. Harmaline, an important beta-carboline alkaloid, shows effective anti-proliferative action against different types of human cancers and is also found to be a nucleic acid targeting natural molecule. This review sought to address the different signal pathways of apoptosis by harmaline in different cancer cell lines and simultaneously to characterize the structure activity aspects of the alkaloid with different motifs of nucleic acid to show its preference, biological efficacy and genotoxicity. The results open up new insights for the design and development of small molecule-based nucleic acid therapeutic agents. [ABSTRACT FROM AUTHOR]

Two new guaiane-type sesquiterpenes, wenyujinolides A (1) and B (2), were isolated from the ethanol extract of Curcuma wenyujin, together with 10 known compounds. Their structures were established by extensive spectroscopic methods (IR, ESIMS, HRESIMS, ECD, 1D and 2D NMR) and comparison of their NMR data with literatures. Compounds 1 and 2 were evaluated for the inhibition of NO production in LPS induced RAW 264.7 macrophages. [ABSTRACT FROM AUTHOR]

Purpose: Higher dietary intake or higher circulating levels of the trace element boron have been associated with beneficial effects on human health. However, the relationship between plasma boron levels and survival in the general population is not known. Therefore, we aimed to assess the association between plasma boron concentrations and all-cause mortality in a population-based cohort from northern Germany (n = 863 individuals; median age 62.3 years, 42.8% women). Methods: Plasma boron concentrations (median 31.9 µg/L [22.9; 43.5]) were measured by inductively coupled plasma-mass spectrometry. Cox proportional hazards regression models adjusted for relevant confounders were used to associate plasma boron concentrations with all-cause mortality. Results: After a median follow-up time of 11 years, n = 99 individuals had died. In the overall sample, plasma boron concentrations were associated with all-cause mortality in the crude model (HR: 1.07 [95% CI 1.03–1.11] per 5-unit-increment). However, multivariable adjustment rendered the association non-significant (HR: 1.03 [95% CI 0.99–1.07]). Sex-stratified analyses revealed slightly higher mortality hazards with increasing plasma boron concentrations in women (HR: 1.11 [95% CI 1.03–1.18], pInteraction = 0.034), but not in men (HR: 1.00 [95% CI 0.95–1.06]). Conclusion: We conclude that in a moderate-sized sample from the general population, higher plasma boron concentrations were associated with a higher risk of all-cause mortality in women, but not in men. Due to the low number of events in the female subsample (n = 27), this observation has to be interpreted with caution. [ABSTRACT FROM AUTHOR]

In Cardiovascular Rehabilitation (CR), patient adherence to the maintenance phase is a major challenge. Virtual reality-based therapy (VRBT) promotes acute hemodynamic and autonomic repercussions similar to traditional rehabilitation and can increase patient adherence to the program. However, it is unknown whether the combination of VRBT to a traditional CR manages to maintain or even improve clinical and autonomic variables in long term. To analyze whether VRBT combination in a traditional CR can maintain or improve clinical and autonomic variables in cardiac patients in the maintenance phase of these programs. Twenty-six volunteers (62.04 ± 12.22 years) were evaluated, who underwent an initial assessment and two other assessments (in the sixth and 12th week) of the following outcomes: systolic and diastolic blood pressure, respiratory rate, pulse saturation of oxygen, heart rate, perceived exertion, and cardiac autonomic modulation, using linear and non-linear heart rate variability methods. Except for the apparent lack of clinical significance observed in Shannon Entropy, LF (nu), and HF (nu), the combination of VRBT as routine in a traditional program did not cause significant changes in the analyzed variables. combination of VRBT was able to maintain the chronic hemodynamic and autonomic repercussions caused by traditional CR. [ABSTRACT FROM AUTHOR]

A simple glass system [Li2O–B2O3–NiO] was prepared via the melt-quenching method. This article attempts to outline the structural-optical relationships of Ni ions-bearing lithium borate glass. XRD confirmed the glassy nature of the samples. The increase in density confirmed the formation of a rigid network constructed by BO 4 units. Infrared spectra analysis confirmed a strong structure conversion from BO 3 to BO 4 units, with observed mitigation in non-bridging oxygen bonds. Optical absorbance spectra were analyzed to extract optical features. Nickel ions were exploited to disclose the surrounding environment in glass. A set of optical transitions of nickel ions in octahedral forms were assigned at 1287, 815, 487 and 425 nm, which are exploited to probe ligand field effects. A decrease in splitting energy values and increased interelectronic repulsion values were obtained. This is owing to the weak intensity of the interaction of Ni ions with surrounding ligands and the localization of d-electrons, respectively. These variations led to a strong enhancement in the ionicity of bonding nature. Furthermore, the brown color of the samples confirmed the occupancy of Ni 2 + in octahedral sites. Moreover, the indirect optical band gap increased due to the harsh reduction in NBO. These findings pave the way toward developing optical materials with the desired optical features. [ABSTRACT FROM AUTHOR]

Based on the Galerkin method with Chebyshev polynomials, we numerically solve the Orr-Sommerfeld problem with high accuracy. We calculate the spectra of the planeparallel Poisseuille and Couette flows, the Blasius flow, and flows with pressure gradient above a flat semi-infinite plate for different values of the wave number and the Reynolds number. [ABSTRACT FROM AUTHOR]

In this paper, we discuss properties of the singular value decomposition (SVD-decomposition) within the framework of the analysis of the numerical rank in ill-posed problems for determining frequency properties of discrete sequences consisting of trigonometric binomials. The properties of the numerical rank of the SVD-decomposition are indicated. We propose an algorithm for determining the frequencies of trigonometric binomials involved in the original function that forms a discrete sequence; this algorithm is based on estimates of the numerical rank. We obtain a stable criterion for estimating the numerical rank based on the arithmetic-mean estimators of the pseudo-null-space of the trajectory matrix. Also, we present the results of numerical experiments that demonstrate the consistency of the arithmetic-mean estimator of the pseudo-zero-space for the analysis of the spectrum of noisy sequences. [ABSTRACT FROM AUTHOR]

In the realm of Earth observation and remote sensing data analysis, the advancement of hyperspectral imaging (HSI) classification technology is of paramount importance. Nevertheless, the intricate nature of hyperspectral data, coupled with the scarcity of labeled data, presents significant challenges in this domain. To mitigate these issues, we introduce a self-supervised learning algorithm predicated on a spectral transformer for HSI classification under conditions of limited labeled data, with the objective of enhancing the efficacy of HSI classification. The S3L algorithm operates in two distinct phases: pretraining and fine-tuning. During the pretraining phase, the algorithm learns the spatial representation of HSI from unlabeled data, utilizing a masking mechanism and a spectral transformer, thereby augmenting the sequence dependence of spectral features. Subsequently, in the fine-tuning phase, labeled data is employed to refine the pretrained weights, thereby improving the precision of HSI classification. Within the comprehensive encoder–decoder framework, we propose a novel spectral transformer module specifically engineered to synergize spatial feature extraction with spectral domain analysis. This innovative module adeptly navigates the complex interplay among various spectral bands, capturing both global and sequential spectral dependencies. Uniquely, it incorporates a gated recurrent unit (GRU) layer within the encoder to enhance its ability to process spectral sequences. Our experimental evaluations across several public datasets reveal that our proposed method, distinguished by its spectral transformer, achieves superior classification performance, particularly in scenarios with limited labeled samples, outperforming existing state-of-the-art approaches. [ABSTRACT FROM AUTHOR]

High-precision waveform identification and measurement are effective for waveform detection and evaluation in signal processing. The accuracy of waveform identification, precision of measurement, and speed of response are important indicators of waveform measurement instruments. To detect the waveform accurately, a hold and attenuation circuit divided into two is designed, and the STM32F4 microcontroller is used to accurately capture and perform spectrum analysis using a high-precision analog-to-digital converter based on fast Fourier transform technology to identify key parameters, such as waveform type, frequency, peak-to-peak value, and duty cycle. To improve the recognition accuracy and response speed, technical solutions, such as high-frequency sampling and over-zero detection, are used to improve the system efficiency. Algorithm simulation, circuit simulation, and physical testing show that the high-precision waveform synchronization recognition circuit and algorithm can accurately recognize various essential waveforms in the voltage and frequency ranges of 50 mV ≤ VPP ≤ 10 V and 1 Hz ≤ f ≤ 50 kHz, respectively, and simultaneously measure important parameters, such as frequency, peak-to-peak value, and duty cycle with an accuracy within ±1%. Intelligent linkage, no intermediate parameter setting, and a response speed of approximately 0.3 s make it suitable for such applications as fast and high-precision waveform intelligent detection and display. The method is highly integrated, simple to operate, cost-effective, and practical. [ABSTRACT FROM AUTHOR]