Search Results (1,765)

The Lower Cambrian shale has been considered an important target for shale gas exploration in South China. However, systematic research on the differences in pore structure and their controlling factors in shales from different sedimentary facies is still lacking, which hinders the accurate prediction of favorable areas. In this study, pore types, structural parameters, heterogeneity and connectivity of the Lower Cambrian shale samples from the shallow shelf, deep shelf and slope were qualitatively and quantitatively characterized by using field emission scanning electron microscope (FE-SEM), low-pressure CO₂ adsorption (LPCA), low-pressure N₂ adsorption (LPNA) and multifractal theory, in order to reveal the reservoir characteristics and differences among these sedimentary facies. The results show that organic pores dominate the pore space in shales from different sedimentary facies, but their morphology and abundance are controlled by the depositional environment. The shallow shelf shales are characterized by scattered organic pores and abundant intragranular pores. Deep shelf shales feature uniformly distributed bubble-like organic pores and have the highest non-micropore volume. Slope shales contain the most developed micropores, with organic pores mainly occurring within organic matter (OM). Total organic carbon (TOC) is the primary factor controlling pore development. It affects pore connectivity and heterogeneity by regulating the development of pore space. Micropore connectivity increases with TOC content. In contrast, non-micropore connectivity first increases and then decreases as TOC increases. The influence of mineral components on shale pore structure varies with sedimentary facies. Clay minerals promote micropore development in shallow and deep shelf shales by adsorbing abundant OM. Carbonate minerals inhibit micropore development through diluting TOC content and cementing pore. However, dissolution of carbonate minerals can contribute to non-micropore space in shallow shelf shales. Deep shelf and slope shales with TOC between 4% and 6% have optimal pore volume, high connectivity, and low heterogeneity, and are the main intervals for forming high-quality shale reservoirs. This study clarifies the pore structure characteristics and controlling factors of shale reservoirs in different sedimentary facies, providing a theoretical basis for predicting and exploring shale gas sweet spots in the Lower Cambrian of South China. Full article

Cropland and rural settlements are core components of rural human–environment systems, and their coordinated development is crucial for regional sustainability, particularly in China’s major agricultural production regions. Taking the Huang-Huai-Hai region as the study area, this study systematically investigates the spatiotemporal evolution of cropland and its coupling relationship with rural settlements using land use data from 1990 to 2020. Grid-based analysis and multiple spatial modeling methods were employed. The results show that: (1) From 1990 to 2020, the cropland in the region decreased by a net total of 21,021.94 km², with annual dynamic degrees ranging from −0.13% to −0.28%. Cropland conversion to other land uses far exceeded conversion from others, with construction land being the primary destination. Among these, rural settlements and urban construction land accounted for 43.75% and 55.58% of the total cropland loss, respectively. (2) The spatial distribution of cropland exhibited a distinct pattern of “hot in the center and south, cold in the periphery and north” (Moran’s I = 0.232, p < 0.001), indicating significant positive spatial autocorrelation. Hot spot areas clustered in the North China Plain and the Huang-Huai Plain, while cold spot areas were distributed in the Yanshan–Taihang mountains and the hilly regions of the Shandong Peninsula, clearly controlled by topography. (3) Cropland change exhibited stage-specific characteristics. The pattern was relatively stable during 1990–2000. During 2000–2010, cropland conversion to other uses intensified, with high-value conversion areas concentrated around urban agglomerations. In the 2010–2020 period, these high-value conversion areas diffused from the core plain areas to urban fringe zones. (4) The spatial coupling between cropland and rural settlements was predominantly characterized by the Moderately Coordinated Type (MCT), accounting for 48.38–58.44% of the area. However, the proportion of Rural Settlement-Dominant Type (RC) increased from 15.51% to 21.58%, indicating a trend toward intensifying human–environment conflicts. Overall, the Huang-Huai-Hai region experienced significant cropland changes. While its spatial pattern remains relatively stable, the coupling relationship between cropland and rural settlements is deteriorating, posing challenges to regional food security and rural sustainable development. Full article

Laser-induced acoustic communication is a highly adaptable cross-medium technique that combines the advantages of optical transmission through air and acoustic transmission underwater. However, poor signal stability at high repetition frequencies currently hinders its widespread application. To address this, this paper proposes an innovative scanning focal-point method to enhance stability. Traditional methods such as beam scanning, focus control, and distributed interaction are primarily aimed at enhancing sound pressure in a specific direction, achieving near-field/far-field focusing, or improving the signal-to-noise ratio through coherent synthesis of ultrasonic intensity. In contrast, the method proposed in this paper is intended to avoid the interference of droplets and vapor generated by single-point breakdown under high repetition frequencies, which would otherwise degrade the laser-acoustic conversion efficiency. It is therefore an active defense strategy specifically targeting the stability of laser-induced acoustic communication. First, optical simulation software was used to analyze the effects of surface ripples and bubbles on focal spot displacement and size. Next, a single-pulse experimental system was developed to measure the range and duration of surface depressions caused by optical breakdown. Finally, a scanning focal-point system was constructed for comparative experiments, with results recorded via hydrophones and high-speed cameras. The maximum laser-induced acoustic signal generated by the scanning focal-point method is 7.4 times that produced by single-point breakdown. The experimental results demonstrate that the scanning focal-point method can effectively avoid the influence of water surface disturbance and steam on the optoacoustic conversion efficiency and significantly improve the amplitude and stability of the laser-induced acoustic signal. Full article

Psilocybin, a psychedelic drug with reported anxiolytic and antidepressant potential, is rapidly metabolized to its active metabolite psilocin. However, a lack of adequate toxicity studies and tissue distribution studies currently restricts its development and application. This study combined behavioral assays in zebrafish with desorption electrospray ionization mass spectrometry imaging (DESI-MSI) to systematically evaluate the acute neurotoxicity of psilocybin and characterize the in vivo spatial distribution of its active metabolite, psilocin. The novel tank test was used to evaluate zebrafish following a 4 h exposure to psilocybin at three different doses (20, 40, and 80 μM; n = 6 per group). Statistical analysis of the data was performed using ANOVA. Behavioral analyses revealed that exposure to psilocybin induced pronounced neurobehavioral alterations, including hyperactivity and disrupted swimming patterns, as evidenced by significant increases in the number of zone transitions and shuttle frequency. We established a DESI-MSI-based method for quantitative mapping and visualization of psilocin in zebrafish tissues. Methodological validation indicated that a linear relationship between ion intensity, spotted amount (R² = 0.9947), and reproducibility (RSD < 15%) is suitable for quantitative analysis of psilocin in zebrafish tissues. Spatial distribution maps showed that following continuous exposure for 4 h, psilocin was widely distributed across multiple tissues, such as the eye, brain, heart, liver, and kidney, with marked accumulation in the brain and the periportal regions of the liver. Relative psilocin signal intensity revealed a dose-dependent increase in tissue drug levels. The dose-dependent increase in both behavioral hyperactivity and brain psilocin levels points to a consistent relationship, in line with a central site of action. Collectively, these findings demonstrate that DESI-MSI provides a visual and efficient strategy for studying drug distribution in biological tissues from exposed animals. The neurobehavioral toxicity phenotypes and distinct tissue distribution patterns of psilocin uncovered in this study offer critical insights into the biological effects and potential risks of this psychoactive substance. Full article

Under climate change, the increasing typhoon intensity poses a severe threat to fishery harbor safety through storm surges and extreme waves. Traditional empirical management approaches fail to capture the complex wave-surge coupling inside harbors, leading to risk blind spots in berth allocation. This study enhances the fishery harbor disaster resilience by employing high-resolution coupled wave-storm surge modeling, taking Xinying Central Fishing Harbor (Hainan, China) during Super Typhoon Yagi (September 2024) as a case study. A Holland typhoon model integrated with ERA5 reanalysis data was used to reconstruct the wind field, which subsequently drove a one-way coupled MIKE 21 FM–SW model to simulate regional tides and deep-water waves. A Boussinesq wave model was then applied to resolve nearshore shallow-water wave transformations inside the harbor. Model validation showed strong agreement with observations: correlation coefficients of 0.97 for tides in Xinying station and 0.95, 0.97, 0.93 for significant wave heights in three buoys around Hainan island, with root-mean-square errors of 0.19 m and 0.67, 0.69, 0.31 m, respectively. The Boussinesq wave simulations revealed detailed spatial distributions of wave heights inside the harbor during the typhoon. Based on these simulations, a dynamic berth zoning strategy was developed, mapping safety zones for different vessel sizes according to wave-height tolerance (e.g., ≤0.6 m for medium-sized trawlers). This framework can provide potential support for decision-making regarding fishing vessel refuge during typhoons, maximizing safe capacity while minimizing capsizing risks. Overall, this study demonstrates a feasible pathway from advanced numerical modeling to practical engineering management, supporting a transition from experience-based to data- and model-driven disaster prevention for coastal fishery harbors. Full article

Semi-batch nitration processes involve substantial heat release, and local reactant enrichment may induce hot-spot formation and increase the risk of thermal runaway. However, global indicators such as the volume-averaged reactor temperature cannot adequately characterize local thermal hazards or quantitatively describe the redistribution of reaction heat under practical flow conditions. In this study, a three-dimensional transient computational fluid dynamics (CFD) model coupled with reaction kinetics, fluid flow and heat transfer was established for the semi-batch nitration of 4-chlorobenzotrifluoride (4-Cl-BTF). On this basis, a CFD-based quantitative framework was proposed to characterize local heat distribution and hot-spot evolution directly from the predicted temperature field. The roles of feed location, stirring speed, feeding time, and impeller type were then investigated. The results show that hot-spot evolution is dominated by the spatial mismatch between local heat generation and heat transport rather than by the global thermal response alone. Insufficient mixing and excessive instantaneous feed flux intensified local reactant enrichment, thereby promoting early hot spot formation. In contrast, feed location and impeller type mainly affected the migration and connectivity of hot spots by reshaping the internal circulation pathway. The present work provides an initial quantitative description of hot spot propagation under realistic impeller-driven flow conditions, and offers a spatially resolved basis for local thermal risk assessment and operating condition optimization in semi-batch nitration reactors. Full article

To address heat accumulation, localized hot spots, and non-uniform temperature distribution in large-capacity lithium iron phosphate energy storage battery modules under high ambient temperature and high-rate charge/discharge conditions, this study proposes a fin-enhanced phase change material (PCM)-air hybrid thermal management structure for a 100 Ah prismatic lithium iron phosphate battery and a 2P18S energy storage battery module. First, the battery thermal model is validated using single-cell experimental data reported in the literature. Subsequently, a three-dimensional transient fluid–solid coupled heat transfer model is established by considering transient battery heat generation, PCM solid–liquid phase change, air-side flow and heat transfer, and temperature-dependent thermophysical properties. User-defined functions are employed to implement the transient heat source and temperature-dependent material properties. Under identical boundary conditions, the thermal management performances of three configurations, namely Fin-Air, PCM-Air, and Fin-PCM-Air, are compared. The effects of ambient temperature (20 °C, 25 °C, and 30 °C) and inlet air velocity (1 m/s, 2 m/s, and 3 m/s) on the maximum module temperature, temperature uniformity, PCM liquid fraction evolution, and flow field distribution are quantitatively analyzed. The results show that, compared with the Fin–Air system without PCM and the PCM-Air system without fins, the Fin-PCM-Air configuration reduces the maximum module temperature by 1.57% and 0.25%, respectively, at an ambient temperature of 30 °C and an inlet air velocity of 3 m/s. After four charge–discharge cycles, the peak maximum temperature of the module is approximately 38.56 °C, and the peak maximum temperature difference remains below 3.6 K, indicating good temperature uniformity and latent heat buffering capability. In addition, the air velocity trade-off analysis indicates that increasing the inlet air velocity can improve cooling performance but also increases the air-channel pressure drop and fan power consumption. Therefore, the Fin-PCM-Air structure is more suitable for high-thermal-load conditions, and its practical application should comprehensively consider cooling benefits, additional mass, manufacturing cost, and long-term reliability. This study provides a reference for the design and engineering application of hybrid thermal management structures for large-capacity energy storage battery modules. Full article

Background/Objectives: Pseudomonas aeruginosa is a major cause of healthcare-associated infections, and the global rise of multidrug-resistant (MDR) strains has created an urgent need for alternative therapeutics. R- and F-type pyocins are phage tail-like bacteriocins that selectively kill P. aeruginosa by binding to lipopolysaccharide (LPS) receptors. We characterized O-serotype distribution and pyocin susceptibility among clinical isolates from central Taiwan to evaluate their therapeutic potential. Methods: A total of 109 ICU-derived P. aeruginosa isolates were analyzed. O-serotypes were determined by PCR, and pyocin gene carriage was confirmed by sequencing. Purified R1, R2, R5, F1, F2, F4, F7, and F12 pyocins were tested using spot assays. LPS profiles were examined by SDS-PAGE to explore structural correlates of resistance. Synergistic effects of combined R- and F-type pyocins were assessed in MDR isolates. Results: The most prevalent serotypes were O6 (23.9%), O2/O5/O16/O18/O20 (20.2%), O1 (16.5%), and O11/O17 (15.6%). Susceptibility was strongly serotype-dependent: O1 and O6 were highly sensitive to both pyocin types, whereas the O2/O5/O16/O18/O20 group showed marked resistance. SDS-PAGE demonstrated that resistant isolates possessed densely packed long-chain O-antigens, likely shielding LPS core receptors from pyocin binding. F-type pyocins exhibited bactericidal activity comparable to R-types, and R/F pyocin cocktails produced synergistic killing against MDR isolates. Conclusions: These findings provide an updated serotype profile of P. aeruginosa in Taiwan and highlight the importance of LPS structural variability in pyocin susceptibility. These results underscore the potential of pyocin-based cocktails as a promising precision-medicine strategy to inhibit the planktonic growth and biofilm formation of multidrug-resistant P. aeruginosa isolates. Full article

Tan spot of wheat, caused by the fungus Pyrenophora tritici-repentis (Ptr), is one of the most destructive foliar diseases of wheat worldwide and in Kazakhstan. Expansion of wheat plantings, the adoption of no-till methods, and the use of ineffective fungicides contribute to the accumulation of inoculum and the spread of the pathogen. Despite the important role of fungicides in plant protection, data on the susceptibility of Ptr populations in Kazakhstan are lacking. This study, for the first time, assessed the susceptibility of Ptr isolates from various regions of Kazakhstan to QoI and DMI fungicides. A predominance of genotypes associated with ToxA (82.9%) was found, with a limited distribution of ToxB (7.9%). Propiconazole demonstrated the highest efficacy, inhibiting mycelial growth by an average of 70.85%, followed by pyraclostrobin (69.04%), while azoxystrobin demonstrated lower efficacy (41.47%). Molecular analysis revealed the widespread prevalence of the G143A mutation in the cytochrome b gene, associated with resistance to the QoI fungicide. These results indicate the emergence of strobilurin resistance in Ptr populations in Kazakhstan and highlight the need for regular monitoring of fungicide susceptibility and the development of effective resistance management strategies. Full article

Deep tight sandstone reservoirs are characterized by strong microscopic pore structure heterogeneity and commonly exhibit a high-porosity, low-permeability profile, posing significant challenges for effective reservoir evaluation and “sweet spot” prediction. The microscopic pore structure of 209 tight sandstone samples from the deeply buried Huagang Formation in the Xihu Depression, East China Sea Basin, was systematically characterized by integrating multiple analytical techniques, including casting thin sections, scanning electron microscopy (SEM), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and high-pressure mercury injection (HPMI). The results indicate that the reservoir space is dominated by mesopores (55.48%) and transition pores (32.39%), with macropores (2.09%) and micropores (10.04%) being relatively underdeveloped. A significant vertical heterogeneity in reservoir quality is observed. The H4 member exhibits superior properties, characterized by a higher average movable fluid saturation (averaging 46%) and better pore connectivity. In contrast, the H5 member is more compact, with a notably higher proportion of bound fluid (averaging 47%). The differences in reservoir quality are controlled by a sedimentary–diagenetic coupling mechanism. High-energy, coarse-grained facies underwent a constructive pathway involving chlorite coating protection and dissolution enhancement, forming high-quality pore networks. In contrast, low-energy, fine-grained facies experienced a destructive pathway dominated by intense compaction and cementation, leading to the deterioration of pore structure. The petrophysical properties of the deep reservoirs are primarily governed by the three-dimensional connectivity and spatial distribution of effective “pore-throat assemblages” composed of dominant throats. Accordingly, a “binary” pore structure development pattern is established for the deep tight sandstone reservoirs in the study area. This pattern posits that the reservoir space is heterogeneously composed of a minority of connected “effective percolation assemblages” and a majority of isolated “ineffective assemblages”. Full article

The long-term stability of submerged sandbars and protected shorelines in large alluvial rivers depends on the serviceability of flexible mattresses installed on the riverbed. Distributed fiber optic sensing is one of the few practical methods for monitoring deformation along these underwater systems over engineering-scale distances. Yet BOTDR-derived strain-difference profiles are often heavily contaminated by noise and rarely have reliable clean references. To address this issue, this study develops TrendBlend-BSFormer, a blind self-supervised denoising framework for in situ BOTDR strain data from underwater flexible mattresses. The framework combines four key features: blind-spot masking, a one-dimensional encoder decoder backbone, a Transformer bottleneck for long-range spatial dependence, and a multi-scale trend-detail blending branch with dual signal-noise heads. The framework was validated using annual and daily BOTDR field data from the Yudaizhou shoreline protection project in the Yangtze River, containing 9343 and 9875 valid measurement points, respectively. TrendBlend-BSFormer achieved pseudo-SNR/RMSE/MAE values of 14.22 dB, 15.03 με and 12.05 με for the annual data set and 5.32 dB, 8.02 με and 6.45 με for the daily data set, improving the pseudo-SNR by 1.45 dB and 2.95 dB relative to the published BiLSTM-CNN benchmark. It also reduced the high-frequency energy ratio from 0.172 to 0.011 for the annual data and from 0.424 to 0.112 for the daily data. The denoised profiles suppress isolated spikes while preserving mechanically plausible peaks, valleys, and short-range fluctuations, indicating that blind self-supervised denoising can provide a more physically credible strategy for BOTDR-based monitoring in complex underwater environments. Full article

With the widespread application of stainless steel rail vehicles, the resistance spot-welding process between stainless steel and low-carbon steel has become one of the key connection processes in vehicle body manufacturing. However, due to the differences in the material physical properties of these two types of steel, problems such as center offset often occur during the welding process. This study adopts the finite element analysis method to systematically analyze the changes in the force field and the temperature field during the welding process after adding a nickel intermediate layer between the two materials, as well as its impact on the physical properties of the joint. The results of the finite element analysis and the physical experiments show that adding a nickel intermediate layer can effectively suppress the center deviation of the weld nugget, optimize the microstructure of the nugget, improve the continuity of the microhardness distribution, and thereby enhance the joint strength of the spot welding. Full article

This study examines the determinants of regulated electricity contract prices in Colombia during the period 2009–2021, with a particular focus on the role of electricity-market fundamentals and macroeconomic conditions. Although regulated contracts are designed to reduce exposure to short-term volatility, limited evidence exists on how their price formation behaves across different segments of the distribution. To address this issue, the analysis combines quantile regression with autoencoder-based dimensionality reduction, allowing the incorporation of a large set of macroeconomic variables without overparameterizing the model. The results show that regulated contract prices are more consistently associated with electricity-system factors than with broad macroeconomic conditions. In particular, the spot price becomes significant only in the upper quantiles, where it appears to operate as an indicator of operational stress, while hydropower and thermal generation exhibit localized effects across the distribution. By contrast, most macroeconomic factors display weak, uneven, or non-significant effects, with only the exchange-rate-related component becoming clearly relevant at relatively high price levels. A robustness analysis based on principal component analysis broadly supports these patterns. Overall, the evidence suggests that the Colombian regulated market behaves as a relatively stable contractual system, in which price formation is shaped mainly by electricity-sector conditions, indexation rules, and long-term risk-management mechanisms, while macroeconomic influences appear more limited and non-uniform across quantiles. Full article

The functionality of ionomeric membranes is influenced by small changes of several parameters. Aqueous network formation by phase separation between the hydrophilic and hydrophobic parts of the polymer is one critical factor for water and ion transport. In particular, the transport of highly charged ions like ${\mathrm{V}}^{3+}$ is not well understood. The unsteady diffusion in Nafion, a sulfonic acid based cation exchange polymer, using ${\mathrm{V}}^{3+}$ profiles obtained with micro X-ray fluorescence ($0.5 \mathsf{\mu }$m spot over a $180 \mathsf{\mu }$m scan) yields a diffusion coefficient of $4\times {10}^{-13} {\mathrm{m}}^2{\mathrm{s}}^{-1}$ at ${\lambda }_{H_{2}O/S{O}_3}=12$ and at ca. $20 °$C. It is confirmed that the concentration profile can be described by an error function formalism. The diffusivity, determined from the entire profile, represents mainly the transport into a vanadium free environment with very low ionic strength as the membrane was conditioned in ultra-pure water. The macroscopic ion transport is influenced by local molecular interactions, interconnection of water pockets and long range ionic interactions. The local interactions of ${\mathrm{V}}^{3+}$ were studied using molecular dynamics (MDs) simulations. The MD simulation studies diffusion at a constant ion concentration and short length scale (ca. 30 nm). It gives insights on the effects of dissolved ${\mathrm{V}}^{3+}$ ions on the local structure. Radial distribution functions reveal that at low hydration, the vanadium ions have an ordering effect on water molecules. The diffusion coefficient of ${\mathrm{V}}^{3+}$ is determined on a molecular level from the mean-square displacement yielding $2.5\times {10}^{-10} {\mathrm{m}}^2{\mathrm{s}}^{-1}$ for ${\mathrm{V}}^{3+}$ ions at a membrane water content of ${\lambda }_{H_{2}O/S{O}_3}$ = 6. The phenomenon in which the diffusivity decreases over longer length scales was documented before for water and ${\mathrm{H}}^{+}$ in Nafion; however, this was by only about one order of magnitude. The experimental microscopic approach described by us is universally applicable, e.g., to environments of higher ionic strength, ions with different charges, and different types of ion-exchange membranes. Longer diffusion times allow us to distinguish between different concentration regimes. Full article

This study examines whether retail social media sentiment and community attention explain daily net capital flows into U.S. spot Bitcoin exchange-traded funds (ETFs), and whether issuer brand visibility conditions that relationship. We construct a balanced panel of $N=10$ ETFs over $T=514$ trading days (January 2024 to January 2026) and combine it with 162,819 cleaned Reddit posts to derive three AI-driven discourse variables: engagement-weighted sentiment, community attention, and a novel issuer-specific BrandScore. Entity fixed-effects regressions show that neither aggregate sentiment nor BrandScore level alone significantly predicts fund-level flows; however, the Sentiment $\times$ BrandScore interaction is significant ($\widehat{\beta }=2.930$, $p=0.038$), indicating that sentiment becomes economically meaningful only when attached to a visible issuer. This interaction survives two-way (entity + date) fixed effects ($p=0.012$) and winsorization ($p=0.004$). Panel quantile regressions reveal distributional heterogeneity in the brand-sentiment channel. Rolling 90-day window estimation confirms the mechanism is episodic, with the interaction achieving significance in 62.8% of subsample windows. These results provide suggestive evidence for a brand-filtered sentiment transmission mechanism in digital asset markets. Full article