Search Results (8,728)

In this study, Mo/β-Ga₂O₃ vertical Schottky barrier diodes (SBDs) were fabricated using a sputtering process, and the electrical characteristics were evaluated as a function of post-annealing temperature. β-Ga₂O₃ is an ultra-wide bandgap semiconductor (UWBG) with a bandgap of about 4.8 eV and a critical breakdown field of 8 MV/cm, a promising material for high-voltage power switching applications. Mo (molybdenum) has a higher work function (~4.95 eV) than the electron affinity (~4.0 eV) of β-Ga₂O₃, its melting point (2623 °C) is higher than Pt (1768 °C) and Ni (1455 °C), so it has excellent thermal stability, and it is selected as a Schottky metal. The device is a structure in which a Si-doped β-Ga₂O₃ epitaxial layer (10 μm, N_d-N_a = 2.2 × 10¹⁶ cm⁻³) is grown on an Sn-doped β-Ga₂O₃ substrate (415 μm, N_d-N_a = 4.5 × 10¹⁸ cm⁻³). The Ti/Au (10/40 nm) was used for the back ohmic junction and Mo (300 nm) was used for the front Schottky junction. Post-annealing treatment was performed at 400, 500, and 550 °C using a rapid thermal annealing process (RTA) in an Ar gas atmosphere, and in this process, the Schottky junction and ohmic junction were formed simultaneously. Electrical characteristics including current-voltage (I–V), capacitance-voltage (C–V), Schottky barrier height (SBH), ideality factor (n), turn-on voltage (V_on), on-resistance (R_on), on/off ratio, and breakdown voltage (BV) were evaluated. No obvious Schottky characteristics were observed before post-annealing treatment, which means that As-deposited Mo does not form a rectifying junction on the β-Ga₂O₃ without post-annealing treatment. After post-annealing treatment, the I–V curve of the Schottky rectification characteristics could be confirmed under all three conditions. Among the three conditions, the device annealed at 500 °C exhibits best performance, with an SBH of 0.96 eV, n of 1.01, V_on of 0.72 V, R_on of 13.8 mΩ·cm², an on/off ratio of 10⁹, a breakdown voltage of −474 V, and a PFOM of 16.3 MW/cm². As a result of temperature-dependent I–V measurement, as chuck temperature increased, the reverse leakage current increased and SBH decreased in all devices, which is consistent with the thermally activated carrier transport. These results demonstrate that the Mo/β-Ga₂O₃ SBDs are a thermally stable contact for power device applications. Full article

3D-printed structures are an important direction in green construction, but layer-wise deposition forms interlayer interfaces that strongly influence the axial compressive performance of printed walls. This paper reviews interlayer bonding, anisotropy, strengthening strategies, and component-level load-bearing behavior of 3D-printed concrete walls within a “material–process–interface–component” framework and distils three main insights. First, anisotropy ranking is not universal. Although previous studies often report higher strength in the X-direction, anomalous cases and differences in direction definition indicate that this ranking is jointly affected by material systems and process parameters; therefore, simple deterministic statements should be avoided. Second, this review synthesizes the concept of an “optimal intervention zone” to explain why strengthening effectiveness does not increase monotonically with intervention intensity, but is influenced by interlayer bond strength, stress distribution, and reinforcement orientation. Beyond a reasonable range, new weak links may be introduced. Third, 3D-printed concrete walls and masonry structures both exhibit load-bearing behavior governed by horizontal weak planes. Masonry systems may therefore provide a useful design reference, although further development is required to reflect printed-interface characteristics. Overall, the key bottleneck is the lack of a cross-scale transfer chain from material interfaces to component performance. Cross-scale predictive models, interlayer bond testing and grading, and interface-performance-centered standardized design are important pathways toward engineering application. Full article

This paper investigated the lubricant stability and anti-biofouling performance on slippery liquid-infused nanostructured surfaces (SLIPSs) using thermodynamic and interfacial energy analyses. ZnO nanorods were synthesized on indium tin oxide substrates with and without a ZnO seed layer by electrochemical deposition and subsequently infused with PDMS-based silicone oil. The seed-layer-assisted growth produced densely packed and vertically aligned ZnO nanorods. Interfacial energy analysis showed that the resulting SLIPSs satisfied the criterion for resistance to water-induced lubricant displacement (ΔE₂ = 64.14 mJ·m⁻²), indicating effective lubricant retention, whereas non-seeded surfaces exhibited reduced lubricant stability. Consistent with this prediction, the seed-layer-assisted SLIPSs retained droplet mobility following spin testing at 2500 rpm, although the reduced sliding velocity indicated a decline in slippery performance. Anti-biofouling evaluation using Escherichia coli (XL1-Blue) revealed that the SLIPSs effectively suppressed bacterial attachment, reducing surface coverage to below 0.3% after 24 h of incubation. In comparison, the pristine ITO and ZnO nanorods exhibited values of 50.8% and 54.6%, respectively. Subsequent surface free energy analysis demonstrated that lubricant infusion reduced the work of adhesion to 77.92 mJ·m⁻². These findings provide insight into the interfacial interactions governing lubricant retention and bacterial attachment on SLIPSs. Full article

Groundwater management presents a challenge for open-cast phosphate mining within the Beni Amir deposit, Oulad Abdoun Basin, Morocco, where future mining operations are progressively reaching deeper saturated phosphate layers. This study integrates six Electrical Resistivity Tomography (ERT) profiles, eleven Magnetic Resonance Sounding (MRS) measurements, hydrostratigraphic modeling, 690 borehole logs, 580 piezometric measurements, and pumping-test results from 14 production wells to characterize the multilayer aquifer system. The comprehensive interpretation identifies three water-bearing zones: a shallow Eocene aquifer located within the Lutetian–Ypresian succession at depths approximately between 2 and 20 m, an intermediate Danian–Thanetian to Maastrichtian phosphate-bearing aquifer situated at depths ranging from 20 to 60 m, and a deeper Senonian marly limestone aquifer occurring below 60 m. Saturated zones are generally associated with low resistivity values, commonly below 28 Ω·m, and MRS-derived mobile water contents ranging from 0.3% to 4.4%. The hydraulic conductivity derived from MRS data exhibits a range of one and a half orders of magnitude across the majority of soundings, from 1.5 × 10⁻⁶ to 5 × 10⁻⁵ m/s. A comparative analysis with pumping tests shows that MRS-derived hydraulic conductivity is generally greater than well-test estimates, with localized discrepancies that may reflect scale effects, lithological heterogeneity, inversion uncertainties, and the necessity for localized calibration. As a working hypothesis, areas spatially associated with ephemeral streambed channels may represent potential zones of localized recharge or inflow, possibly where erosional truncation reduces the continuity of confining layers. The resultant hydrostratigraphic framework constrains saturated zones and hydraulic heterogeneity, thereby establishing a foundation for forthcoming groundwater flow modeling and mine dewatering evaluations. Full article

Large-area three-dimensional polyjet printing (3DPP) of continuous photopolymer laminates directly onto knitted fabrics provides a potential route toward technical textile applications beyond localized decorative features. This study investigated acrylic photosensitive resin (APR) laminates measuring 330 × 432 mm deposited onto a Nylon 66 interlock-knitted fabric. 12- and 20-layer laminates were produced in one-sided and two-sided configurations, and their morphology and tensile behavior were evaluated in the wale and course directions before and after 20 h of accelerated xenon-arc weathering. Scanning electron microscopy (SEM) showed a continuous external APR layer with localized resin entry into inter-yarn and inter-filament spaces, indicating a form-fitting physical connection between the resin and the knitted structure; interfacial strength was not measured. Before weathering, the 20-layer two-sided (20L-2S) architecture exhibited the highest maximum engineering stress, reaching 13.11 ± 0.37 MPa in the wale direction and 7.44 ± 0.28 MPa in the course direction. In contrast, the 20-layer one-sided (20L-1S) architecture retained substantially greater extensibility, reaching maximum engineering strains of 183.94 ± 2.45% and 217.34 ± 2.88% in the wale and course directions, respectively. Thus, two-sided printing maximized load-bearing capacity, whereas one-sided 20-layer printing provided a better balance between reinforcement and preservation of the large-strain response of the knitted substrate. Accelerated weathering reduced the maximum engineering stress of fabric-supported laminates by 5.4–18.7% and maximum engineering strain by 2.1–21.1%, depending on architecture and loading direction. Unsupported APR laminates exhibited 59.9–77.2% increases in maximum engineering stress after exposure, without a corresponding increase in strain capacity. The contrasting response is consistent with APR post-curing or stiffening combined with reduced Nylon 66 extensibility, although chemical and interface-specific tests are required to distinguish these mechanisms. The results demonstrate that continuous 3DPP can produce mechanically integrated textile–photopolymer laminates with tunable strength–extensibility relationships relevant to flexible technical textile structures. Full article

The accumulation of dissolved species during the in situ leaching (ISL) of uranium can lead to ore-layer blockage and reduced production capacity. Clay minerals, including montmorillonite, chlorite, kaolinite, and illite, are the primary cementing and filling materials in sandstone-hosted uranium deposits in China. However, previous studies have predominantly focused on the leaching behavior of uranium minerals, while systematic investigations into the dissolution mechanism of clay minerals under CO₂+O₂ conditions remain scarce. In this study, laboratory dissolution experiments, scanning electron microscopy–energy-dispersive spectroscopy (SEM-EDS), computed tomography (CT) scanning, and field verification were conducted to systematically investigate the dissolution behavior of major clay minerals and their contribution to ore-layer blockage under CO₂+O₂ leaching conditions. The results indicate the following: (1) Montmorillonite exhibited the most significant dissolution, with granular deposits rich in Ca and Si formed on its surface, which were inferred to be Ca-Si-rich precipitates. (2) Obvious changes in both microstructure and macroscopic physical properties of clay minerals were observed before and after leaching, with porosity decreasing by approximately 12.96% and permeability decreasing by approximately 10.16%. (3) Field verification revealed that the scale in the ore layer, filter cloth blockage, and resin surface caking were primarily composed of silica gel and hydroxide/carbonate precipitates of Al, Ca, and Fe, which are closely related to the dissolution and leaching of clay minerals. This study confirms that montmorillonite is the main source of clogging substances, and long-term closed circulation of injection and extraction leads to the accumulation of precipitates, exerting a significant impact on the uranium-leaching system. The findings provide a theoretical basis for anti-clogging and permeability enhancement in CO₂+O₂ ISL operations. Full article

To investigate the effect of the TiN interfacial layer on the microstructure and optoelectronic properties of AZO/Ag/AZO multilayer films, four configurations, namely AAA, ATAA, AATA, and ATATA, were deposited on the glass substrates by magnetron sputtering. All the films exhibited a preferential ZnO (002) orientation. When TiN was located above the Ag layer, the ATAA film preserved a pronounced Ag (111) diffraction feature and exhibited the best overall optoelectronic performance, the average transmittance increased from 78.4% for AAA to 85.9%, the resistivity decreased from 7.2 × 10⁻⁵ to 6.3 × 10⁻⁵ Ω·cm, and the figure of merit increased from 0.64 to 0.71 Ω⁻¹. In contrast, when Ag was grown directly on TiN, the Ag (111) diffraction peaks of the AATA and ATATA films were markedly weakened, the average transmittance decreased to 59.0% and 62.0%, respectively, and the resistivity increased sharply to 1.2 × 10⁻³ and 9.5 × 10⁻⁴ Ω·cm, respectively. These results demonstrate pronounced interfacial asymmetry and stacking-sequence dependence in the TiN regulation of AZO/Ag/AZO films, with the ATAA configuration exhibiting the best structure–optics–electronics synergy. Full article

The 7075-T6 aluminum alloy exhibits excellent specific strength due to the presence of precipitated η′ phase, but its surface mechanical performance under demanding conditions is often limited. In this study, a horizontal cylindrical magnetron sputtering system was used to deposit TiN coatings on the surface of 7075-T6 aluminum alloy to enhance its surface mechanical properties and structural performance. The effects of deposition temperature, substrate bias voltage, and N₂/Ar flow ratio on the microstructure, surface morphology, phase composition, hardness, and residual stress of the coatings were systematically investigated. The results showed that at 80 °C, enhanced lateral atomic diffusion promoted the transformation of the coating growth mode from coarse columnar crystals to dense quasi-layered structures. The surface roughness decreased from 0.193 μm at room temperature to 0.077 μm, the (111) preferred orientation significantly increased, the hardness reached 383 HV, and the compressive stress was −2.8 GPa. However, when the temperature was raised to 120 °C, grain coarsening and TiN/7075Al interface thermal mismatch stress dominated, and the hardness decreased by approximately 19.3%. At −80 V bias, the atomic impact effect produced by ion bombardment made the coating densified optimally, with the lowest surface roughness of 0.068 μm, a hardness of 377 HV, and a compressive stress of −3.1 GPa; at −150 V, excessive bombardment led to severe re-sputtering and lattice distortion, resulting in a compressive stress of −6.8 GPa and a hardness of 351 HV. When N₂/Ar = 10/25, the reaction sputtering kinetics and chemical thermodynamic conditions reached the optimal balance, achieving the highest diffraction peak signal-to-noise ratio and the narrowest full width at half maximum. These results reveal the temperature-dependent competitive relationship between thermally activated coating densification and thermal mismatch-induced structural degradation, providing insights into the optimization of TiN coating deposition parameters on aluminum alloys. Full article

The use of uniform spray volume rates for fruit trees with different canopy sizes is common in orchard spraying with plant protection unmanned aerial vehicles (UAVs), whereas the applicability of Leaf Wall Area (LWA)- and Tree Row Volume (TRV)-based methods to UAV spraying remains insufficiently validated. This study evaluated canopy size-based spray volume optimization and droplet deposition and penetration along the vertical canopy profile in a mountainous Nanguo pear orchard. The results showed that, under a uniform spray volume rate, small canopy trees exhibited significantly higher droplet deposition and ground deposition than large canopy trees, indicating greater potential spray losses. LWA- and TRV-based adjustment reduced the spray volume rate for small canopy trees by 43.0% and 49.0%, respectively, while maintaining comparable deposition in the upper and middle canopy layers. However, deposition in the lower canopy and on abaxial leaf surfaces remained limited, indicating that conventional LWA and TRV methods do not fully account for the top-down deposition characteristics of UAV spraying. Along the vertical canopy profile, finer atomization levels generally favored droplet penetration into the lower canopy, whereas increasing the spray volume rate increased overall deposition but did not significantly improve vertical penetration. Flight speed showed no consistent effect on penetration within the tested range. The results highlight canopy size as a key factor in UAV spray deposition. Canopy size-based variable-rate application can reduce spray volume rate while maintaining effective deposition, but further optimization should consider rotor-induced airflow and canopy structure. Full article

Non-layered two-dimensional (2D) chromium-based chalcogenides have garnered significant attention due to their distinctive magnetic, electronic, and optical properties. In this work, we report the controllable synthesis of high-quality rhombohedral Cr₂S₃ nanosheets on mica substrates via an atmospheric pressure chemical vapor deposition (CVD) strategy. The as-grown rhombohedral Cr₂S₃ nanosheets exhibit pronounced optical second-harmonic generation (SHG) signals, which show thickness-dependent enhancement and a strong dependence on both the linear excitation and detection polarization configurations. Most notably, temperature-dependent SHG measurements reveal a distinct inflection point near the Néel temperature (T_N ≈ 120 K), where the SHG intensity exhibits a sharp enhancement upon cooling below T_N. This behavior arises from the additional magnetic dipole contributions activated by magnetic ordering, establishing SHG as a sensitive probe of magnetic phase transitions in non-layered 2D magnetic materials. Furthermore, circularly polarized SHG signals exhibit nearly 100% circular polarization at low temperatures. This work systematically elucidates the nonlinear optical response characteristics of rhombohedral Cr₂S₃ and their correlation with magnetic ordering transitions, laying an experimental foundation for the application of 2D non-van der Waals magnetic materials in nonlinear optoelectronics and spin-optoelectronic devices. Full article

Mechanical sand-control screens are core completion components for maintaining sand retention and flow conductivity in oil, gas, geothermal, hydrate, and underground gas storage wells. This review summarizes recent progress in the plugging mechanisms, diagnostic indicators, and plugging-removal technologies of mechanical sand-control screens. The reviewed studies show that screen plugging is a multi-mechanism process controlled by external sand bridging, internal fines invasion, drilling/completion fluid residues, chemical scaling, organic deposition, and their coupled cementation effects. External plugging is mainly associated with slot- or pore-entrance bridging and filter-cake compaction, whereas internal plugging is controlled by fines retention in mesh layers, prepacked gravel, or tortuous porous media. Pressure drop, permeability damage/recovery, produced-sand particle-size distribution, and microstructural characterization are key indicators for evaluating plugging severity and treatment effectiveness. Hydraulic jetting, mechanical vibration, ultrasonic treatment, acidizing, oxidizing systems, thermochemical treatment, and physical–chemical combined methods are compared in terms of mechanisms and applicability. The analysis indicates that single treatments are usually insufficient for strongly cemented multicomponent plugging; a sequential strategy of chemical weakening followed by physical stripping and flowback is more suitable for complex field conditions. Future work should focus on green and selective chemical systems, downhole diagnosis-guided treatment selection, and integrated sand-control designs combining plugging prevention, monitoring, and removal. Full article

The structural use of three-dimensional concrete printing remains limited by the directional weakness introduced during extrusion and layer-by-layer deposition. Although 3DPC offers major advantages in formwork elimination, architectural freedom, and automated construction, its printed architecture produces interfaces, pore networks, and reinforcement discontinuities that do not exist in the same form in conventionally cast concrete. This review examines the anisotropic behavior of 3DPC by linking its architectural arrangement, physical interlayer mechanisms, and chemical durability-related processes. The analysis shows that anisotropy develops from the combined effects of filament orientation, interlayer bonding quality, pore morphology, cold-joint formation, mechanical interlocking, hydration continuity, and reinforcement limitations. Weak interlayer regions act not only as preferred paths for crack initiation and propagation under tensile, flexural, shear, and compressive loading, but also as transport channels that accelerate water absorption, chloride ingress, carbonation, sulfate attack, and freeze–thaw deterioration. The review further highlights that fiber, textile, FRP, and discrete reinforcement strategies can reduce some consequences of anisotropy, but their effectiveness depends on whether they bridge the weaker interlayer regions rather than merely reinforcing the filament direction. SEM-based observations confirm that microstructural discontinuities, fiber-matrix debonding, irregular hydration products, and connected pores provide the material-level basis for the directional response of printed concrete. Overall, anisotropy should be treated as a design-critical feature of 3DPC rather than as a secondary defect. Reliable structural application requires coordinated control of mixture rheology, deposition parameters, interlayer timing, curing, toolpath design, and reinforcement layout. Full article

Continental shale reservoirs exhibit pronounced multi-scale heterogeneity, with reservoir quality governed by the interplay of lamina assemblages, bedding continuity, and lithological spatial variability. Conventional digital outcrop modeling (DOM) primarily targets geometric reconstruction and three-dimensional (3D) visualization of sedimentary bodies, which is insufficient for the fine-scale structural characterization and quantitative modeling required for shale reservoirs. Here we present a Digital Shale Outcrop Modeling method (DSOM) tailored to continental shale reservoirs, exemplified by the Gulong Shale in the Qingshankou Formation (Upper Cretaceous) of the Songliao Basin, northeastern China. DSOM integrates six sequential modules: digital outcrop reconstruction, digital section interpretation, virtual well construction, virtual well correlation, 3D structural modeling, and parameter extraction. A high-precision digital outcrop model covering 0.369 km² was constructed from 1885 calibrated UAV images (DJI Mavic 3 Enterprise) using Structure-from-Motion (SfM) photogrammetry, yielding derived products including a digital outcrop model (DOM), digital surface model (DSM), digital elevation model (DEM), orthomosaic, and dense point cloud. Seven virtual wells were extracted along the outcrop strike, and a unified lithological classification comprising seven lithotypes was established. A regionally persistent rusty-yellow ferruginous siltstone layer served as a marker bed for virtual well correlation. Results reveal a distinct vertical lithological transition: the section above the marker bed is dominated by muddy deposits, with black mudstone and dark-gray silty mudstone collectively accounting for 52.84% of the total area, whereas the section below the marker bed exhibits a marked increase in silt-grade material, with gray siltstone reaching 32.78%. This vertical evolution reflects a depositional shift from relatively high-energy to low-energy conditions. Using the virtual wells as conditioning data, 3D lithological probability models for all seven lithotypes were constructed via Sequential Indicator Simulation (SIS), achieving quantitative representation of lithological spatial distribution and lateral variability under bedding constraints. Our results demonstrate that DSOM effectively converts outcrop digital information into reservoir structural data, providing reliable constraints for multi-scale structural characterization, 3D geological modeling, and heterogeneity evaluation of the Gulong Shale. More broadly, DSOM establishes a methodological framework for digital characterization of fine-grained sedimentary reservoirs, bridging the gap between outcrop-scale observations and subsurface reservoir modeling. Full article

This paper reports the effects of formed perfluoroalkylsilane self-assembled monolayers (SAMs) on the tribological and corrosion properties of TiO_x-incorporated diamond-like carbon (TiO_x-DLC) coatings deposited on a Ti6Al4V substrate. The SAMs were formed using 1H,1H,2H,2H -perfluorodecyltrichlorosilane (FDTS) and (3,3,3 -trifluoropropyl) trichlorosilane (FPTS) compounds. Their presence was confirmed using techniques such as ellipsometry, time-of-flight secondary ion mass spectrometry, and Fourier-transform infrared spectroscopy. The results of the ball-on-disc test indicate the role of the structure of the created SAMs on their tribological properties. The FDTS compounds with longer alkyl chains favor the creation of a well-packed layer bonded to the TiO_x-DLC coating. This hydrophobic structure allows for obtaining the lowest coefficient of friction (0.180) during tribological tests. The results of electrochemical tests indicate that the SAM modification reduces the barrier properties of TiO_x-DLC and provides enhanced kinetic stability against carbon matrix oxidation at higher anodic potentials. Full article

Renewable energy can be harvested from salinity gradients using reverse electrodialysis (RED); however, the open-circuit voltage and power output of this process can be significantly reduced by multivalent ions and natural organic matter found in natural waters. In this work, a tailor-made polyepichlorohydrin-based anion exchange membrane (AEM) surface was modified using an electrophoretic layer-by-layer (LbL) polyelectrolyte assembly. Negatively charged poly(styrene sulfonate) (PSS) and positively charged poly(ethyleneimine) (PEI) were employed to construct three-layer architectures in which PEI served as the interlayer. The results indicate that the molecular weight of the PEI interlayer strongly influences the surface composition and charge of the final AEMs. RED experiments performed in the presence of Na₂SO₄ revealed that AEMs incorporating the high-molecular-weight PEI exhibited enhanced apparent Cl⁻/SO₄²⁻ selectivity and delivered an increased power density. Fouling tests using a real humic–fulvic acid mixture demonstrated that the hydrophilic PSS top layer effectively mitigated organic fouling and preserved RED performance. Furthermore, short-term stability testing provided a preliminary indication of the stability of the polyelectrolyte layers under short-term operating conditions. This study highlights the critical role of interlayer molecular weight in defining the surface chemistry, apparent ion selectivity, and antifouling behavior of LbL-modified tailor-made AEMs, providing important design guidelines for improving RED performance in realistic feedwaters. Full article