Search Results (381)

High safety gel polymer electrolyte (GPE) is used in lithium metal solid state batteries, which has the advantages of high energy density, wide temperature range, high safety, and is considered as a subversive new generation battery technology. However, solid-state lithium batteries with multiple layers and large capacity currently have poor cycle life and a large gap between the actual output cycle capacity retention rate and the theoretical level. In this paper, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP)/polyacrylonitrile (PAN)—lithium perchlorate (LiClO₄)—lithium lanthanum zirconium tantalate (LLZTO) gel polymer electrolytes was prepared by UV curing process using a UV curing machine at a speed of 0.01 m/min for 10 s, with the temperature controlled at 30 °C and wavelength 365 nm. In order to study the performance and failure mechanism of multilayer solid state batteries, single and three layers of solid state batteries with ceramic/polymer composite gel electrolyte were assembled. The results show that the rate and cycle performance of single-layer solid state battery with gel electrolyte are better than those of three-layer solid state battery. As the number of cycles increases, the interface impedance of both single-layer and three-layer electrolyte membrane solid-state batteries shows an increasing trend. Specifically, the three-layer battery impedance increased from 17 Ω to 42 Ω after 100 cycles, while the single-layer battery showed a smaller increase, from 2.2 Ω to 4.8 Ω, indicating better interfacial stability. After 100 cycles, the interface impedance of multi-layer solid-state batteries increases by 9.61 times that of single-layer batteries. After 100 cycles, the corresponding capacity retention rates were 48.9% and 15.6%, respectively. This work provides a new strategy for large capacity solid state batteries with gel electrolyte design. Full article

On-chip spectral splitting structures with compact footprints hold tremendous potential for next-generation molecular sensing applications in the mid-infrared region. Here, we propose and theoretically investigate a carefully designed structure comprising a tilt grating and metalenses for dual-band spectral splitting with enhanced bandwidth. The tilt grating serves to separate the wavelength bands, and the metalenses following the grating guarantee a smooth transition of light into single-mode waveguides, giving rise to transmittances of 73.59% at 4 μm and 68.74% at 11 μm. The use of this tandem structure results in a significant footprint reduction and a remarkable 25.8% bandwidth enhancement over conventional approaches. The proposed spectral splitting scheme, with its broad wavelength range applicability, unlocks new pathways for on-chip simultaneous multi-target molecule detection. Full article

CdS nanowires have garnered considerable attention lately for their promising potential in next-generation nanolaser devices, attributed to their relatively high stability and exceptional emission efficiency within the Ⅱ–Ⅵ semiconductor family. In this study, tin-doped CdS nanowires with varying dimensions were synthesized, and the underlying mechanisms responsible for the formation of micro-cavities within these nanowires were systematically explored through scanning electron microscopy (SEM) analysis and photoluminescence mapping. The results show that a very distinct hexagonal-shaped micro-cavity is observed on the cross-section of CdS nanowires, and the size of the micro-cavity is determined by the radius of the nanowire. Additionally, through the use of angle-resolved micro-fluorescence Fourier imaging technology, it is found that under high excitation density conditions, the micro-cavity mode is more prominent at higher collection angles, which is consistent with the mode of the wall-pass cavity micro-cavity. Finally, the formation of the full reflection spectrum of the micro-cavity mode is confirmed through the wavelength shift and intensity shift phenomena related to the excitation power. These results further deepen our understanding of the micro-cavity modes in tin-doped cadmium sulfide nanowires, which may be of great significance for the application of these nanowires in new optical devices. Full article

Lasers are increasingly used in the biomedical field because of their concentrated energy, good stability, ease of use, and other advantages, promoting the development of precision medicine to a higher level. Medical laser equipment has transformed from a single therapeutic tool in an intelligent and precise diagnostic system. Existing clinical laser equipment has significant technical bottlenecks regarding soft-tissue ablation precision and multimodal diagnostic compatibility, which seriously restricts its clinical application. High-power thulium-doped fiber lasers with operating wavelengths of 1.9–2.1 μm provide a revolutionary solution for minimally invasive surgery due to their high compatibility with the absorption peaks of water molecules in biological tissues. This study reviews recent advances in high-power thulium-doped fiber lasers for minimally invasive therapies in the biomedical field. Breakthrough results in four major clinical application scenarios, namely, urological lithotripsy, tumor precision ablation, disfiguring dermatological treatment, and minimally invasive endovenous laser ablation, are also summarized. By systematically evaluating its potential for multimodal diagnostic and therapeutic applications and thoroughly exploring the technical challenges and strategies for clinical transformation, we aim to provide a theoretical basis and practical guidance for the clinical transformation and industrialization of new-generation medical laser technology. Full article

This research presents a novel square-shaped photonic crystal fiber (PCF)-based surface plasmon resonance (SPR) sensor, designed using the external metal deposition (EMD) technique, for highly sensitive refractive index (RI) sensing applications. The proposed sensor operates effectively over an RI range of 1.33 to 1.37 and supports both x- polarized and y-polarized modes. It achieves a wavelength sensitivity of 15,800 nm/RIU and 14,300 nm/RIU, and amplitude sensitivities of 11,584 RIU⁻¹ and 11,007 RIU⁻¹, respectively, for the x-pol. and y-pol. The sensor also reports a resolution in the order of 10⁻⁶ RIU and a strong linearity of R² ≈ 0.97 for both polarization modes, indicating its potential for precision detection in complex sensing environments. Beyond the sensor’s structural and performance innovations, this work also explores the future integration of artificial intelligence (AI) into PCF-SPR sensor design. AI techniques such as machine learning and deep learning offer new pathways for sensor calibration, material optimization, and real-time adaptability, significantly enhancing sensor performance and reliability. The convergence of AI with photonic sensing not only opens doors to smart, self-calibrating platforms but also establishes a foundation for next-generation sensors capable of operating in dynamic and remote applications. Full article

Background: Measuring contrast sensitivity for each of the three cone types separately allows for a more precise and clinically valuable assessment of color vision. This study examined how pupil size affects cone contrast sensitivity (CCS). Methods: This study included 50 participants of equal gender. The mean age was 20.88 (±1.8) years. Using the ColorDx, a Landolt C stimulus of various sizes in an adaptive screening mode, we sequentially determined contrast sensitivity for long-, medium-, and short-wavelength stimuli. Two consecutive measurements were performed on participants, one with their natural pupil size (range 4–5 mm diameter) and, subsequently, with six artificial eye pupils (1 mm to 6 mm). Results: Generally, the 1 mm pupil size caused the greatest reduction in contrast sensitivity for two of the three cones. There was no significant main effect of sex (F = 0.96, df = 1, p = 0.32) on the log cone contrast sensitivity of the L-cone. However, pupil size had a significant main effect (F = 116.1, df = 6, p < 0.001). Within each sex, the log CCS was significantly reduced as the pupil size decreased compared with the normal pupil size. Conclusions: New technologies that assess individual cone pathway functions could potentially assist in identifying early or progressive conditions that may impact color vision pathways from the retina to the brain. Standardized protocols—such as controlled retinal illumination—are critical to avoid misinterpretation. Full article

Aflatoxin B1 (AFB1) is widely present in maize silage feed and poses strong toxicity, seriously threatening livestock production and food safety. To achieve efficient and accurate non-destructive detection of AFB1, this study proposes a quantitative prediction method based on hyperspectral imaging technology. Using the full-spectrum bands after SG, SNV, MSC, FD, SD, and SNV + FD, MSC + FD, SNV + SD, MSC + SD preprocessing, the characteristic wavelengths selected by CARS, BOSS, and RF feature selection methods, and the augmented bands generated by Mixup data augmentation as input features, three models were developed for AFB1 content prediction: a linear WPLSR_SD_Mixup_QPE model, a nonlinear SVR_SD_Mixup_PCA model, and a deep learning CNN_SD_Mixup_WMSE_SA model. The results demonstrated that SD preprocessing was the most suitable for AFB1 detection in maize silage, and the Mixup data augmentation method effectively improved model performance. Among the models, SVR_SD_Mixup_PCA achieved the best performance, with an ${\mathrm{R}}_{\mathrm{p}}^2$ of 0.9458, RMSEP of 3.1259 μg/kg, and RPD of 4.2969, indicating high prediction accuracy and generalization capability. This study fills the gap of hyperspectral image technology fused with artificial intelligence algorithm in the application of quantitative detection of AFB1 content in maize silage and provides a new technical method and theoretical basis for nondestructive testing of corn silage feed. Full article

The emergence of new-generation hyperspectral satellites offers more potential for mapping soil properties. This study presents the first assessment of EnMAP (Environmental Mapping and Analysis Program) hyperspectral imagery for soil organic matter (SOM) prediction and mapping using actual spectral data from 282 soil samples. Different spectral preprocessing techniques, including Savitzky–Golay (SG) smoothing, the second derivative of SG, and Standard Normal Variate (SNV) transformation, were evaluated in combination with embedded feature selection to identify the most relevant wavelengths for SOM prediction. Partial Least Squares Regression (PLSR) models were developed under different pre-treatment scenarios. The best performance was obtained using SNV preprocessing with the top 30 EnMAP bands (wavelengths) selected, giving R² = 0.68, RMSE = 0.34%, and RPIQ = 1.75. The combination of SNV with feature selection successfully identified significant wavelengths for SOM prediction, particularly around 550 nm in the Vis–NIR region, 1570–1630 nm, and 1600 nm and 2200 nm in the SWIR region. The resulting SOM predictions exhibited spatially consistent patterns that corresponded with known soil–landscape relationships, highlighting the potential of EnMAP hyperspectral data for mapping soil properties despite its limited geographical availability. While these results are promising, this study identified limitations in the ability of PLSR to extrapolate predictions beyond the sampled areas, suggesting the need to explore non-linear modeling approaches. Future research should focus on evaluating EnMAP’s performance using advanced machine learning techniques and comparing it to other available hyperspectral products to establish robust protocols for satellite-based soil monitoring. Full article

This paper presents an experimental and numerical investigation of submerged vegetation flow, with a particular focus on vegetation-related terms, especially in the vicinity of the free end. Experimental results indicate that substantial shear stress is observed near the top of vegetation, where the drag coefficient increases significantly due to the disturbance caused by the free end. Furthermore, wake generation is notably suppressed, particularly at heights where wake-generated turbulence dominates, leading to a reduction in turbulent kinetic energy (TKE). A numerical model based on the volume-averaged Reynolds-averaged Navier–Stokes (VARANS) equations was developed, incorporating a vertically varying drag coefficient. The two-scale $⟨k⟩-⟨\epsilon ⟩$ turbulence model is further modified with the inclusion of a new damping function to capture the suppression of wake generation. The model accurately simulates both unidirectional and oscillatory flows, as well as the associated turbulence structures, with good agreement with experimental measurements. The influence of the tips on wave-induced currents, mass transport and TKE distribution is also investigated. It was found that the tip effects play a significant role in strengthening wave-induced currents at the top of loosely arranged, short, and sparse vegetation, with shear kinetic energy (SKE) serving as a critical component of TKE, contributing to the nonuniform distribution. Both Eulerian currents and Stokes drift contribute to streaming in the direction of wave propagation near the vegetation top, which intensifies with increasing solid volume fraction, while tip effects further enhance the onshore mass transport. Within the vegetation, mass transport is more sensitive to wave period and wave height, shifting from onshore to offshore as wavelength increases under constant water depth. Full article

In this study, novel focusing performances of high-numerical-aperture (NA) micro-Fresnel zone plates (FZPs) with selective occlusion are identified and investigated through numerical calculations based on vectorial angular spectrum (VAS) theory, and further rigorously validated using the finite-difference time-domain (FDTD) method. The central occlusion of a standard micro-FZP can significantly extend the depth of focus while keeping the lateral size of the focusing spot essentially unchanged. When a standard micro-FZP only retains two separated transparent rings and all other rings are obstructed, it will result in multi-focus phenomena; at the same time, the number of focal points is equal to the difference in number between the two separated transparent rings. Furthermore, a focusing light needle can be generated by combining the central occlusion and wavelength shift of a standard micro-FZP. This study not only provides new ideas for the design and optimization of micro-FZPs but also provides reference for the expansion of practical applications of FZPs. Full article

Building shoreline position databases able to capture event- to centennial-scale coastal changes is critical for scientists to improve knowledge of past coastal dynamics and predict future changes. Thanks to the commissioning of several satellites acquiring recurrent high-resolution optical images over coastal areas, coastal scientists have developed methods for detecting the shoreline position from satellite images in most parts of the world. These methods use image band analyses to delineate the waterline and require post-processing to produce time-consistent satellite-derived shorelines. However, the detection accuracy generally decreases with increasing tidal range. This work investigates an alternative approach for meso- and macrotidal coasts, which relies on the delineation of the boundary between dry and wet sand surfaces. The method was applied to the high-energy meso-macrotidal km-scale Cap Ferret sand spit, SW France, which has undergone large and contrasted shoreline changes over the last decades. Comparisons with topographic surveys conducted at Cap Ferret between 2014 and 2020 have shown that the raw satellite-derived wet/dry line reproduces well the mean high water shoreline, with an overall bias of 1.7 m, RMSE of 20.2 m, and R2 of 0.86. Building on this, the shoreline variability at Cap Ferret was investigated over the 1984–2021 period. Results have evidenced an alongshore gradient in the dominant modes of variability in the last 2 km of the sand spit. Near the tip, the shoreline has chronically retreated on the decadal scale at about 8.4 m/year and has been strongly affected on the interannual scale by the onset and migration of shoreline undulations having a wavelength of 500–1200 m and a cross-shore amplitude of 100–200 m. Some 3 km away from the sand spit extremity, the shoreline has been relatively stable in the long term, with a dominance of seasonal and interannual variability. This work brings new arguments for using the wet/dry line to monitor shoreline changes from spatial imagery at meso- and macrotidal sandy coasts. Full article

Recently, Cu(I)-based metal halides have attracted tremendous attention owing to their remarkable photophysical properties. However, most of them can only be excited by near ultraviolet (UV) light at a wavelength (generally less than 350 nm) with a wide bandgap, which undoubtedly limits their application in solid-state lighting due to the low excitation efficiency at about 400 nm in devices. Here, we report a new zero-dimensional organic cuprous bromide of (C₁₃H₃₀N)₂Cu₅Br₇ single crystals, which can be excited by visible light (390–400 nm) and give a bright yellow and broad self-trapped exciton emission band with the photoluminescence quantum yield (PLQY) of 92.3% at room temperature. The experimental and theoretical results show that the existence of Cu-Br-Cu metal bonds in a Cu₅Br₇ cluster package produces three components of self-trapped excitons (STE) that emit at room temperature but merge into one at 80 K. This occurs because of the anomalously enhanced electron–phonon coupling and electron–electron coupling in the coupled clusters in this system. These effects cause the excitation near visible light and emission broader at higher temperature. Additionally, their remarkable anti-water emission stability was demonstrated even after soaking in water for 6 h. Finally, a highly efficient white-light-emitting diode (WLED) based on (C₁₃H₃₀N)₂Cu₅Br₇ was fabricated. Full article

Photodynamic therapy (PDT) has garnered significant attention as an effective and safe method for cancer therapy, with ongoing efforts to develop new photosensitizers to enhance its efficacy. This study aimed to develop novel photosensitizers with aggregation-induced emission enhancement (AIEE) properties. A series of 3-phenyl pyrano[4,3-b]quinolizine compounds (3–10) were synthesized by reacting pyrones (1a–e) with 2-pyridylacetate (2a) or 2-pyridylacetonitrile (2b) and then evaluated for their potential as photosensitizers. Spectroscopic analyses revealed that all compounds emitted blue to green fluorescence in ethanol, with emission wavelengths ranging from 446 nm to 515 nm. Compounds 5 and 6, lacking a substituent at position 5 of pyrano[4,3-b]quinolizine, exhibited AIEE behavior in aqueous solution. Furthermore, all compounds produced reactive oxygen species upon exposure to LED light. Notably, compounds 5 and 6 demonstrate high singlet oxygen (¹O₂) generation efficiency in water-rich solvents, where they tend to aggregate, contributing to their potential to destroy cancer cells. In vitro studies using human colon cancer cells (Colo205) demonstrated that 5 and 6 exhibited potent anti-tumor activity upon exposure to LED light. These findings suggest that compounds 5 and 6, based on 3-phenyl pyrano[4,3-b]quinolizine, possessing AIEE properties, are potential new photosensitizers for PDT. Full article

We propose a Multispectral Earth Polarization Imager (MEPI), which is located at the Earth–Moon system’s Lagrange point L1. The imager can be used to measure the sunlight reflected by the Earth and the Moon. The measured sunlight has specific polarization information and spectral information, which can provide strong support for a comprehensive understanding of the Earth system and the construction of a perfect Earth–Moon system model. The MEPI provides multispectral images with wavelengths of 400–885 nm, and uses four sub-aperture systems to share a main system. The imager can capture the two-dimensional shape and polarization spectral information of the entire Earth at a spatial resolution of 10 km, and all spectral images can be simultaneously acquired on a single detector. The optical system of the instrument was designed and simulated. The simulation and analysis results showed that the camera can obtain high-quality images of the Earth disc with a 2.5° field of view (FOV). The novel MEPI provides a new way to generate climate-related knowledge from the perspective of global Earth observation. The imager can also be used for lunar observation to obtain spectral polarization information on the lunar surface. In addition, it also shows great potential in other applications of space remote sensing spectral imaging. Full article

Background: Within the solar ultraviolet (UV) spectrum, ultraviolet A rays (UVA, 320–400 nm), although less energetic than ultraviolet B rays (UVB, 280–320 nm), constitute at least 95% of solar UV radiation that penetrates deep into the skin The UV rays are associated with both epidermal and dermal damage resulting from the generation of reactive oxygen species (ROS). Among them, the longest UVA wavelengths (UVA1, 340–400 nm) can represent up to 75% of the total UV energy. Therefore, UVA radiation is linked to various acute and chronic conditions, including increased skin pigmentation and photoaging. Despite many advances in the skin photoprotection category, there is still a growing demand for natural daily photoprotection active ingredients that offer broad protection against skin damage caused by UVA exposure. In our quest to discover new, disruptive, next generation of photoprotective ingredients, we were drawn to pomegranate, based on its diverse polyphenolic profile. We investigated the pericarp of the fruit, so far considered as byproducts of the pomegranate supply chain, to design a novel patented extract “POMAOX” with a desired spectrum of phenolic components comprising of αβ-punicalagins, αβ-punicalins and ellagic acid. Methods: Antioxidant properties of POMAOX were measured using in-tubo standard tests capable of revealing a battery of radical oxygen species (ROS): peroxyl radical (ORAC), singlet oxygen (SOAC), superoxide anion (SORAC), peroxynitrite (NORAC), and hydroxyl radical (HORAC). In vitro, confirmation of antioxidant properties was first performed by evaluating protection against UVA-induced lipid peroxidation in human dermal fibroblasts (HDF), via the release of 8 iso-prostanes. The protection offered by POMAOX was further validated in a 3D in vitro reconstructed T-Skin^TM model, by analyzing tissue viability/morphology and measuring the release of Matrix Metallopeptidase 1 (MMP-1) & pro-inflammatory mediators (IL-1α, IL-1ra, IL-6, IL-8, GM-CSF, and TNF-α) after UVA1 exposure. Results: POMAOX displayed strong antioxidant activity against peroxynitrite (NORAC) at 1.0–3.0 ppm, comparable to the reference vitaminC, as well as singlet oxygen (SOAC) at 220 ppm, and superoxide radicals with a SORAC value of 500 ppm. Additionally, POMAOX demonstrated strong photoprotection benefit at 0.001% concentration, offering up to 74% protection against UVA-induced lipid peroxidation on HDF, in a similar range as the positive reference, Vitamin E at 0.002% (50 µM), and with higher efficacy than ellagic acid alone at 5 µM. Moreover, our pomegranate-derived extract delivered photoprotection at 0.001%, mitigating dermal damages induced by UVA1, through inhibition of MMP-1 and significant inhibition of pro-inflammatory mediators release (including IL-1α, IL-1ra, IL-6, IL-8, GM-CSF, and TNFα) on an in vitro reconstructed full-thickness human skin model with a similar level of protection to that of Vitamin C tested at 0.035% (200 µM). Conclusions: Overall, the novel pomegranate-derived extract “POMAOX” significantly reduced the impact of UVA on human skin, due to its broad-spectrum antioxidant profile. These findings suggest that POMAOX could offer enhanced protection against the detrimental effects of UV exposure, addressing the growing consumer demand for strong photoprotection with skincare benefits. Full article