Search Results (1,472)

To further reveal the degradation mechanism of epoxy coatings under intense ultraviolet radiation in high-altitude environments and clarify its influence on their interfacial adhesion performance, an epoxy coating-cement mortar system was investigated. Ultraviolet (UV) aging tests were conducted, together with attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), surface free energy (SFE) measurements, atomic force microscopy (AFM)-based nano-adhesion force measurements, scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDS), uniaxial tensile tests, and pull-off adhesion strength tests to investigate the evolution of the coating’s characteristic molecular structure, surface polarity, nano-adhesion, coating toughness, macroscopic adhesion performance, and interfacial failure modes at different aging stages. The results showed that the peaks associated with hydroxyl and carbonyl groups in the epoxy coating intensified with increasing UV aging duration. The surface free energy of the coating increased, and its polar component reached 3.9 times the initial value. After 28 d of UV aging, the nano-adhesion force of the coating decreased by 30.1%, its toughness decreased from 2.82 ± 0.052 to 1.21 ± 0.027 MJ·m⁻³, and the adhesion strength between the epoxy coating and the cementitious substrate decreased by 15.7%. In addition, as aging progressed, the failure path gradually shifted from fracture near the substrate surface toward regions near the coating–cementitious substrate interface and within the coating. Correlation analysis further showed that the decreases in coating toughness and nano-adhesion performance were closely associated with the deterioration of macroscopic adhesion strength. Therefore, greater attention should be paid to the optimization of these two properties in practical applications. Full article

To investigate the effects of model selection, time-varying parameters and climatic differences on the carbon emission reduction performance of rural rooftop photovoltaic (PV) systems, this study selected a typical rural residential rooftop PV system in Beijing as the research object. Hourly simulations using the System Advisor Model (SAM) and an operational-period baseline method were employed to optimize the PV array parameters and conduct a multi-factor analysis of carbon emission reductions. The results show that the first-year electricity generation was 15,902 kWh, corresponding to an annual carbon emission reduction of 12.60 tCO₂. The carbon emission reduction estimates obtained using the three irradiance models differed, with a maximum deviation of 0.51 tCO₂. When both PV module degradation and changes in the grid emission factor were considered, the cumulative carbon emission reduction decreased by 68.37 tCO₂ relative to the ideal scenario. Moreover, the faster the grid transition speed, the lower the cumulative carbon emission reduction over the system’s operational period. In addition, extending the analysis from a single region to multiple regions revealed that the annual carbon emission reductions in representative rural residential rooftop PV systems in Beijing and Wuhan differed by 2.94 tCO₂, with differences also observed in their seasonal variation patterns. The assessment of rural rooftop PV systems should comprehensively consider irradiance model selection, module power degradation, grid transition pathways, regional climatic conditions and economic feasibility. Full article

The development of sensitive, low–cost, and visually readable dosimeters for low gamma–ray exposures is important for occupational and environmental radiation monitoring and for other low–dose applications. This work investigates a colorimetric and optical thin–film dosimeter based on polyvinyl alcohol (PVA) containing silver nitrate (AgNO₃) and hafnium oxide (HfO₂). The film was fabricated using a solution–casting technique. The dosimetric response was evaluated over an absorbed–dose range of 22.2–65.2 mGy using diffuse reflectance spectroscopy, Kubelka–Munk (K/S) analysis, CIELAB colorimetry, CMYK image–based analysis, and X–ray diffraction (XRD). Irradiation produced a dose–dependent decrease in visible reflectance and a corresponding increase in optical absorption. The K/S response increased with dose, while CIELAB analysis showed a systematic decrease in lightness and an increase in total color difference (${\Delta \mathrm{E}}_{ab}^{\ast }$), reaching approximately 25 at 65.2 mGy. Linear regression of ${\Delta \mathrm{E}}_{ab}^{\ast }$ over 0–65.2 mGy gave y = 0.399x − 1.0029 with R² = 0.9845. CMYK analysis also showed a clear dose response, with the yellow channel (ΔY) exhibiting the largest relative change among the chromatic channels. XRD identified monoclinic HfO₂ as the dominant crystalline filler phase and showed dose–associated changes in peak intensity, peak position, and the relative prominence of the broad PVA–related feature. At the highest XRD dose, several HfO₂ reflections weakened while the broad contribution near 2θ ≈ 19.9–20° became more prominent. These changes are interpreted as dose–dependent structural modification and partial loss of resolved crystalline order rather than definitive evidence of a newly formed crystalline phase. A surface morphology and microstructure analysis was performed on control and γ–ray–irradiated PVA/HfO₂/AgNO₃ nanocomposite films using scanning electron microscopy (SEM–EDX). The morphological transition to fibrous, tree trunk–like structures seen by SEM is well correlated with the dose–dependent change in composition to higher surface Ag content, supporting the idea that radiation–induced Ag nanoparticle nucleation and growth is the primary degradation mechanism in the irradiated films. The combined optical and colorimetric results demonstrate a measurable response of the PVA/HfO₂/AgNO₃ formulation in the investigated low–mGy gamma–ray range. Full article

New approaches to the band gap engineering of ZnO:Fe/SnO₂ nanocomposites are developed in this study. The main idea is to control the band structure of the material by varying the modifier (iron) content during the preparation of the film-forming sol and the co-evolution of its components. Experimental X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-ray Spectroscopy (EDX) data demonstrate that materials with controlled crystallite size and hierarchical morphology can be obtained with Fe contents ranging from 1 to 6 at.%. For the first time, a combined analysis of XPS data and Tauc plot band gap measurements demonstrates preferential doping of zinc oxide within the composite studied. It is also found that the formation of type II heterostructures at Fe concentrations of up to 4 at.% takes place. The authors suggest that the formation of a Z-scheme heterostructure occurs at iron contents of 5 and 6 at.%, and X-ray amorphous phases act as charge transfer mediators. It is established that the photocatalytic properties of the material are determined by the interrelations between the band structure of the material and the spectral characteristics of the radiation sources, while optical power is not a dominant factor. Using the ZnO/SnO₂ nanocomposite ensures 98.12% decomposition of Brilliant Green in 120 min under short-wave UV radiation, while using the photocatalytic material containing 6 at.% iron ensures 95.84% degradation of the dye in the same time under soft UV radiation. Employing a low-power lamp simulating the solar spectrum in the 380–780 nm range enables 24.91% decomposition of the organic pollutant when using ZnO:Fe(5 at.%)/SnO₂ as a photocatalyst. Full article

Reliable partial discharge (PD) assessment of air-insulated medium voltage (MV) metal-clad switchgear is challenged by the close proximity of adjacent units and the noise environment generated by control, relay, and mechanical or electromechanical equipment within the substation. Combined sensing approaches have been employed to identify primary PD sources and distinguish them from interference signals. Although individual sensing technologies have been extensively studied, no systematic framework has been established to corroborate readings across sensing modalities under controlled, reproducible noise conditions. This study presents a laboratory benchmark performed on an actual 15 kV metal-clad switchgear assembly, incorporating representative PD source configurations and interferences encompassing electrical, acoustic, and electromagnetic noise. Sensors spanning multiple detection classes were evaluated, including acoustic sensors (intrusive and remote airborne, and surface-contact types), high-frequency current transformers (HFCTs), transient earth voltage (TEV) sensors, and a wideband electromagnetic sensor, across both open-access and closed-panel configurations. Testing showed that electrical and electromagnetic noise primarily affects conducted-electrical and radiated-EM channels, while acoustic noise degrades acoustic sensors, leaving each channel type largely unaffected by the other’s interference. This complementary behavior supports a two-path corroboration criterion that reduces false positives and false negatives and informs practical sensor selection for field deployment. Full article

Integrating traditional textile heritage into contemporary furniture design offers an innovative way to preserve cultural identity through modern materials and decorative techniques. This study investigates the color stability of hybrid decorative plywood panels fabricated using mechanical perforation and sewing techniques inspired by traditional textile motifs. The samples were evaluated using UV-induced artificial aging, alongside color measurements before and after exposure, microscopic analysis, and Fourier Transform Infrared Spectroscopy (FTIR). The approach enables traditional decorative patterns to be transferred onto wood-based materials, creating contemporary furniture decorations, while preserving and reinterpreting the textile heritage. Results revealed distinct aging behaviors depending on the finishing system. Changes in total color difference (ΔE*)—4.36 for red thread, 4.21 for unvarnished reference, 3.34 for oiled, 0.72 for water-based, 2.55 for nitrocellulose-based, and 0.52 for epoxy-coated samples—demonstrated that both the coated plywood substrate and the textile thread were affected by aging after 72 h of UV exposure. Epoxy resin and water-based coatings provided the greatest color surface stability, while oil- and solvent-based finishes exhibited varying degrees of chromatic alteration due to their different responses to ultraviolet radiation and moderate temperature. The stitch technique showed good structural compatibility with plywood and preserved the integrity of heritage-inspired motifs after artificial aging for 72 h of UV exposure relative to long-term furniture use, which is a limitation of the present study. However, the red cotton sewing thread was more sensitive to light exposure, showing a slight UV-induced discoloration, with effects varying according to coating type. FTIR investigations demonstrated that UV aging of the cotton thread resulted in some photo-oxidative degradation of cellulose, which may explain the minor incipient microstructural degradation phenomena observed by SEM. Full article

Transparent glazing systems are increasingly required to provide simultaneous control over light transmission, solar heat gain, thermal losses, surface contamination, and environmental durability, creating new challenges for the development of multifunctional coating technologies. This review critically examines advanced optical and self-cleaning coatings developed for transparent glass and polymeric substrates, with particular emphasis on the relationships between materials chemistry, surface/interface chemistry, microstructure, and functional performance. Dielectric multilayers, metal oxides, ceramic coatings, sol-gel-derived hybrid systems, and emerging chromogenic materials are discussed in terms of their chemical compositions, structural characteristics, and mechanisms governing optical, thermal, and surface properties. Particular attention is given to structure–property relationships associated with photosynthetically active radiation (PAR) transmission, near-infrared (NIR) management, thermal emissivity, solar modulation, wettability, and self-cleaning behavior, together with their implications for energy-efficient transparent glazing and greenhouse environments. The influence of coating architecture, porosity, surface roughness, interfacial interactions, and deposition conditions on functional performance and long-term stability is critically evaluated. The advantages and limitations of representative deposition strategies are further compared, considering scalability, process compatibility, substrate sensitivity, and application to heat-sensitive polymeric films. Environmental degradation mechanisms induced by ultraviolet irradiation, moisture, thermal cycling, and mechanical stresses are analyzed to identify the key factors governing coating durability and sustainability. Finally, current knowledge gaps and emerging research directions are identified, highlighting the need for rational materials design, multifunctional integration, scalable fabrication, and improved structure-property-durability correlations for next-generation transparent glazing and greenhouse applications. Full article

Back surface field (BSF) materials are key functional layers that suppress rear-surface recombination and regulate carrier transport in III–V solar cells. This work investigates the performance degradation behavior of GaInP solar cells with AlInP and AlGaInP BSF layers under 1 MeV electron irradiation. Through a combination of optoelectronic measurements and TCAD simulations, the carrier transport and recombination mechanisms before and after irradiation are comprehensively analyzed. Although both devices deliver comparable initial photovoltaic performance, distinct degradation trends emerge under high-fluence electron irradiation. After a cumulative fluence of 1 × 10¹⁵ e/cm², the cell with an AlInP BSF suffers more severe degradation owing to inferior radiation hardness. Irradiation-induced defects reduce the minority-carrier lifetime and enhance Shockley–Read–Hall (SRH) nonradiative recombination, resulting in a 14% drop in short-circuit current density. In contrast, the AlGaInP BSF exhibits favorable radiation tolerance, and the corresponding device undergoes only a 2% loss in short-circuit current density. The influence of the BSF structure on carrier transport and recombination is systematically analyzed, providing experimental and theoretical support for the design of space-grade GaInP top cells. Full article

The operating frequency of a resonant oscillator is determined by the coupled behavior of the resonator, sustaining electronics, package, power supply, mounting conditions, and operating environment. Frequency stability is critical in sensor systems, where oscillators provide references for sampling, synchronization, phase-sensitive measurements, sensor fusion, and distributed sensing. This review examines how these factors affect the short- and long-term stability of quartz oscillators (XOs, TCXOs, and OCXOs) and microelectromechanical systems (MEMS) oscillators. Organized by physical cause rather than device type, the review covers temperature, including gradients and hysteresis, aging, acceleration, vibration, shock, pressure, humidity, power-supply and load variations, electric and magnetic fields, electromagnetic interference, and ionizing radiation. For each factor, the dominant degradation mechanisms and compensation methods are compared across both technologies. The comparison indicates that OCXOs retain an advantage in low-noise timekeeping over long averaging times, whereas advanced MEMS oscillators can approach quartz performance in selected operating regimes while offering smaller size, monolithic integration, and, in ruggedized products, 0.01 ppb/g acceleration sensitivity and 20,000 g shock ratings. In the literature reviewed, appropriate measurement methods exist but are applied inconsistently across technologies. Oscillator selection should therefore be based on a comprehensive error budget covering all relevant environmental and system-level factors. Full article

Nuclear-facility concrete structures perform containment, radiation-shielding, and load-bearing functions under prolonged irradiation; however, phase-dependent damage in heterogeneous concrete cannot be adequately represented by a homogeneous-material approximation. This study investigated the effects of the aggregate, cement matrix, and interfacial transition zone (ITZ) on He-ion transport and primary damage. SRIM-2013 calculations were performed for 1–3 MeV He ions, and the phase-resolved displacements per atom (DPA) profiles were combined by volume-fraction weighting and compared with those of an equivalent homogeneous target. At 2 MeV and a reference fluence of 1.0 × 10¹⁶ ions·cm⁻², the aggregate, cement matrix, and ITZ exhibited DPA peaks of 0.3572, 0.2526, and 0.2749 at depths of 6.0, 7.5, and 9.3 μm, respectively. Increasing the assumed ITZ effective density from 1.47 to 1.89 g·cm⁻³ reduced the mean projected range, DPA peak depth, and DPA peak magnitude by 22.2%, 22.9%, and 12.8%, respectively. At 2 MeV, the phase-weighted DPA index reached a peak of 0.2237 at 6.0 μm, whereas the homogeneous target produced a peak of 0.3020 at 6.6 μm. Relative to the phase-weighted result, the homogeneous-target DPA peak was 35.0% higher and its peak depth was 10.0% greater. Homogenization therefore altered the primary-damage distribution and obscured deeper phase-specific features. The proposed framework provides phase-dependent initial-damage parameters for multiscale assessment of irradiation-induced degradation in nuclear concrete structures; however, experimental calibration is required before the calculated DPA can be related to material-property degradation or structural performance. Full article

Lightning discharges over the Tibetan Plateau are monitored by ground-based networks that locate radiation sources from their low-frequency radio emissions. This study uses the Qinghai Datong network in the northeastern Tibetan Plateau, which records the 50 kHz to 2.5 MHz band over a small area to locate lightning in three dimensions. In such networks, the accuracy of three-dimensional location depends critically on the consistency of the signals recorded across stations, which is progressively degraded by aging analog front-ends and by complex electromagnetic noise. To address this, we propose a phase-preserving denoising scheme, termed WZ, that suppresses both broadband and narrowband noise while keeping the relative timing between stations essentially unchanged, so that the arrival times used for location are preserved. The improvement is illustrated with both simulations and real data. In Monte Carlo simulations, WZ improves the signal-to-noise ratio by 10 dB and reduces the time-of-arrival error to 0.3 μs. Applied to two intracloud flashes of contrasting morphology, WZ recovers substantially more radiation sources and more continuous discharge channels than conventional filtering, at no cost to fit quality, allowing, for example, the downward development of the channel to be tracked quantitatively. The method requires no change to the existing hardware and can be applied to archived data, making it a practical way to improve both current and historical records from long-running low-frequency lightning networks. Full article

Benefiting from excellent high-frequency characteristics and superior radiation tolerance, InP is an indispensable material for next-generation high-speed communications, widely applied in optical communication, 6G radio frequency chips, AI optical interconnection, and aerospace radiation-hardened electronics. Although ion implantation greatly promotes the performance optimization of InP-based devices, it inevitably induces lattice displacement defects that degrade device reliability. Hence, quantitative evaluation of the threshold displacement energy (TDE) and dominant defect configurations in InP is essential. Our calculations reveal that the average threshold displacement energy is 18.20 eV for In atoms and 18.94 eV for P atoms. The E_d distributions for both In and P atoms predominantly lie below 30 eV and rarely exceed 40 eV. From 150 K to 900 K, In and P have a large mass difference and exhibit distinct temperature-dependent trends. The threshold displacement energy of In decreases with increasing temperature, whereas that of P rises as temperature increases. Based on the structural analysis of Frenkel pairs formed by displaced atoms, the dominant interstitial configurations are identified. These results provide detailed insights for damage evaluation and defect structure characterization in InP, benefiting ion implantation process optimization and radiation-hardening design of InP electronic devices. Full article

Background and Clincal significance: Esophageal squamous cell carcinoma (ESCC) classically presents with progressive dysphagia and weight loss, but atypical presentations may redirect the diagnostic workup before the esophageal primary is identified. We report a case illustrating the simultaneous convergence of three diagnostic pitfalls: absence of dysphagia, bone-predominant metastatic presentation initially managed as carcinoma of unknown primary (CUP), and negative p40 staining in a vertebral biopsy in a patient subsequently confirmed to have invasive mid-esophageal squamous cell carcinoma. CasePresentation: A 66-year-old African American man with dementia, active tobacco exposure, and prior alcohol use disorder presented with constipation, abdominal pain, melena, fever, nausea, vomiting, and progressive back pain. Dysphagia or odynophagia was not documented. CT of the abdomen and pelvis demonstrated diffuse lytic osseous metastases. During evaluation and palliation of symptomatic L2 disease, kyphoplasty and radiofrequency ablation were performed, and bilateral core biopsies showed poorly differentiated carcinoma that was AE1/AE3-positive but negative for p40, CK7, CK20, TTF-1, S100, GATA-3, PAX8, and NKX3.1, yielding an initial diagnosis of CUP. Subsequent chest CT revealed esophageal wall thickening with intraluminal debris. Esophagogastroduodenoscopy (EGD) identified a non-obstructive ulcerated mid-esophageal lesion, and biopsy confirmed invasive squamous cell carcinoma. Poor performance status precluded systemic therapy; palliative external-beam radiation was initiated after diagnosis but discontinued because of clinical deterioration, and the patient transitioned to hospice before passing several weeks after diagnosis. Melena is a gastrointestinal alarm feature, and the combination of gastrointestinal bleeding and an esophageal imaging abnormality warrants timely endoscopic evaluation even when dysphagia is not reported or the symptom history is unreliable. Negative p40 staining in a poorly differentiated, potentially decalcified bone specimen may reflect loss of lineage-marker expression, technical antigen degradation, or both. Tissue or plasma genomic profiling and emerging cell-free DNA methylation classifiers could complement the workup but would not replace direct biopsy of a radiographically suspicious esophageal lesion. Conclusions: In metastatic poorly differentiated carcinoma, lack of documented dysphagia should not exclude an esophageal primary, particularly in patients with cognitive impairment. A p40-negative bone biopsy does not rule out squamous lineage. Timely EGD and integrated clinicopathologic assessment are essential when clinical or imaging findings suggest esophageal involvement. Full article

Skin photoaging, primarily driven by UVA radiation, is characterized by the accumulation of senescent fibroblasts and the degradation of the extracellular matrix (ECM). While the roles of reactive oxygen species (ROS) and matrix metalloproteinases (MMPs) are well-documented, the regulatory impact of post-translational glycosylation in this process remains poorly understood. We established a UVA-induced photoaging model in human dermal fibroblasts (HDFs) and employed bulk mRNA-seq and high-throughput lectin microarrays to profile glycomic alterations. The functional role of the sialyltransferase ST6GAL1 was investigated through pharmacological inhibition of cellular sialylation (3Fax-Neu5Ac), siRNA-mediated knockdown, and gain-of-function overexpression. Mechanistic insights were gained via RAS-ERK pathway analysis and validated in a 3D reconstructed human full-thickness skin model (T-Skin™). Glycomic profiling revealed that UVA irradiation triggers a broad increase in α2,6-sialylation in HDFs. We identified ST6GAL1 as the primary enzymatic driver of this remodeling, with its expression upregulated in both photoaged HDFs and 3D skin models. Functional assays demonstrated that ST6GAL1 overexpression induces hallmark features of photoaging, including p16, MMP and γ-H2AX upregulation, G0/G1 cell cycle arrest and increased SA-β-gal activity. Conversely, pharmacological or genetic inhibition of ST6GAL1 effectively mitigated the photoaged phenotype. Mechanistically, ST6GAL1 regulates the expression of p16 via the activation of the RAS-ERK signaling cascade. Our study identifies ST6GAL1-mediated α2,6-sialylation as a novel functional hallmark of skin photoaging, highlighting the association of ST6GAL1 with the RAS-ERK-p16 axis as a potential regulator for targeting UVA-induced skin photoaging and dermal senescence. Full article

This paper presents a methodology to evaluate the entire process of thermal evolution and fracture failure within stay cables subjected to sheath fires. Computer software FDS 2021 and ABAQUS 2021 are applied to build a sequentially thermos–mechanics coupled method integrating thermal, structural, and fracture dynamic analyses in stay cables under sheath fire exposure conditions. Herein, three representative fire scenarios including full-circumferential, top-side, and bottom-side ignition are reconstructed. Further, 127 individual wires, accounting for interstitial cavity radiation and contact heat transfer, are utilized to perform analysis on sectional temperature in stay cables. The results indicate that the ignition mode dictates the cross-sectional temperature gradient, with localized ignitions inducing highly asymmetric thermal fields and pronounced internal bending moments. Elevated temperatures trigger a progressive load redistribution from the degraded fire-facing wires to cooler internal layers. Ultimately, abrupt global fracture occurs when the residual ultimate load-carrying capacity intersects with the actual applied tension, resulting in a fracture morphology that closely corresponds to the spatial thermal distribution. Furthermore, the structural capacity degradation exhibits three distinct time-dependent stages: a slow degradation stage, a sharp decline stage, and a recovery stage. Among the analyzed scenarios, full-circumferential ignition induces the most drastic overall capacity reduction, while bottom-side ignition poses a markedly greater rupture risk than top-side ignition. Full article