Search Results (1,011)

Aiming at the key problems of the material removal rate and surface integrity of existing tools in the lapping of sapphire hard and brittle crystals, an efficient lapping tool has been developed to explore a new process for HFVCD (hot filament chemical vapor deposition) diamond tools to efficiently lap sapphire wafers. With the premise of ensuring the surface roughness of the wafer is Ra ≤ 0.5 μm, the material removal rate is increased to more than 1 μm/h. To explore a high-efficiency lapping process for sapphire wafers using HFCVD diamond tools. The influence of key preparation parameters on the surface characteristics of CVD (chemical vapor deposition) diamond films was systematically investigated. Three types of CVD diamond coating tools with distinct surface morphologies were fabricated. These tools were subsequently employed to conduct lapping experiments on sapphire wafers in order to evaluate their processing performance. The experimental results demonstrate that the gas pressure, methane concentration, and substrate temperature collectively influenced the surface morphology of the diamond coatings. The fabricated coatings exhibited well-defined grain boundaries and displayed pyramidal, prismatic and spherical features, corresponding to high-quality microcrystalline and nanocrystalline diamond layers. In the lapping experiments, the prismatic CVD diamond coating tool exhibited the highest material removal rate, reaching approximately 1.7 μm/min once stabilized. The spherical diamond coating tool produced the lowest surface roughness on the lapped sapphire wafers, with a value of about 0.35 μm. Surface morphology-controllable diamond tools were used for the lapping processing of the sapphire wafers. This achieved a good surface quality and high removal rate and provided new ideas for the precision machining of brittle hard materials in the plane or even in the curved surface. Full article

This paper presents a breakthrough in activating the skin effect at conventional broaching speeds (1–8 m/min) by using laser defocus gradient modification to induce surface embrittlement in martensitic stainless steel Z10C13. Through controlled defocusing, a 50 μm gradient remelting layer was created, which features ultrafine grains (0.8 μm) and a high-density geometrically necessary dislocation (GND) zone (ρGND = 2.27 μm⁻³). The quasi-cleavage fracture was triggered via dislocation pinning by non-oriented low-angle grain boundaries (28.4% LAGBs). Multiscale characterization confirms that this microstructural transformation enhances surface hardness by 12.95% (reaching 31.4 HRC), reduces cutting force by 34.07%, and improves surface roughness by 63.74% (Sz = 28.80 μm). Simultaneously, a parallel crack-deflection mechanism restricts subsurface damage propagation, resulting in a crack-free subsurface zone. These results demonstrate the effectiveness of the embrittlement–toughening dichotomy for precision machining of difficult-to-cut materials under low-speed constraints. Full article

Grain size is critical for metallic material performance, yet conventional ultrasonic methods rely on strong model assumptions and exhibit limited adaptability. We propose a deep learning architecture that uses multimodal ultrasonic features with spatial coding to predict the grain size distribution of GH4099. A-scan signals from C-scan measurements are converted to time–frequency representations and fed to an encoder–decoder model that combines a dual convolutional compression network with a fully connected decoder. A thickness-encoding branch enables feature decoupling under physical constraints, and an elliptic spatial fusion strategy refines predictions. Experiments show mean and standard deviation MAEs of 1.08 and 0.84 μm, respectively, with a KL divergence of 0.0031, outperforming attenuation- and velocity-based methods. Input-specificity experiments further indicate that transfer learning calibration quickly restores performance under new conditions. These results demonstrate a practical path for integrating deep learning with ultrasonic inspection for accurate, adaptable grain-size characterization. Full article

Ten new epipolythiodioxopiperazine (ETP) alkaloids, named corallomycetellains A–J (1–10), along with one known analogue, haematocin (11), were isolated from the fungi Corallomycetella repens HDN23-0007. Their structures, including absolute configurations, were established by comprehensive spectroscopic data and electronic circular dichroism (ECD) calculations. Compounds 1–2 represent the first two examples of aranotin-type ETPs possessing an aromatic indole moiety. Compounds 2–4 all featured a unique C2-methyl disulfide substituent, whereas compound 4 additionally possessed a C2′-oxomethyl group. In in vitro cytotoxicity assays, compounds 7–10, which contained α–α′ polysulfide bridges, exhibited strong anticancer activity, with IC₅₀ values ranging from 1.1 to 9.3 μM. Full article

Hollow-core microstructured optical fibres exhibit excellent properties, such as a low loss, tuneable high birefringence, and low nonlinearity, finding extensive applications across communications, industry, agriculture, medicine, military, and sensing technologies. This paper designs two types of asymmetric hollow-core photonic bandgap fibres featuring a high birefringence and low confinement loss. Both feature a cladding structure of rounded hexagonal honeycomb lattice, while the core structures comprise elliptical hollow cores and rounded rhombic hollow cores, respectively. By adjusting the radius of the cladding air holes and the core structure parameters, this study aims to maximise the birefringence coefficient and minimise the confinement loss. The control variable method is employed to optimise the parameters of two fibres. The simulation results indicate that, at a wavelength of 1.55 μm, the birefringence coefficient of the rhombic core, after parameter optimisation, reaches 1.4 × 10⁻⁴, with the confinement loss achieving 4.4 × 10⁻³ dB/km. Its bending loss remains at the order of 10⁻³ dB/km, indicating that this fibre maintains an exceptionally high transmission efficiency even when wound with a small curvature radius (such as within the resonant cavity of a compact fibre optic gyroscope). The elliptical core’s birefringence coefficient also reaches 3 × 10⁻⁴, with the confinement loss achieving 1.9 × 10⁻¹ dB/km. Specifically, this paper employs bismuth tellurite glass as the substrate material to simulate the performance of elliptical cores. Within a specific refractive index range, the elliptical-core fibre with a bismuth tellurite glass substrate exhibits a confinement loss comparable to quartz glass, whilst its birefringence coefficient reaches as high as 5.8 × 10⁻⁴. Therefore, the hollow-core photonic bandgap fibres designed in this thesis provide valuable reference and innovative significance, both in terms of the performance of two asymmetric core structures and in the exploration of polarisation-maintaining hollow-core photonic bandgap fibres on novel material substrates. Full article

As a cornerstone of China’s energy infrastructure, the coal mining industry relies heavily on the stability of its underground roadways, where the support of soft rock formations presents a critical and persistent technological challenge. This challenge arises primarily from the high content of expansive clay minerals and well-developed micro-fractures within soft rock, which collectively undermine the effectiveness of conventional support methods. To address the soft rock control problem in China’s Longdong Mining Area, an integrated material–structure control approach is developed and validated in this study. Based on the engineering context of the 3205 material gateway in Xin’an Coal Mine, the research employs a combined methodology of micro-mesoscopic characterization (SEM, XRD), theoretical analysis, and field testing. The results identify the intrinsic instability mechanism, which stems from micron-scale fractures (0.89–20.41 μm) and a high clay mineral content (kaolinite and illite totaling 58.1%) that promote water infiltration, swelling, and strength degradation. In response, a novel synergistic technology was developed, featuring a high-performance grouting material modified with redispersible latex powder and a tiered thick anchoring system. This technology achieves microscale fracture sealing and self-stress cementation while constructing a continuous macroscopic load-bearing structure. Field verification confirms its superior performance: roof subsidence and rib convergence in the test section were reduced to approximately 10 mm and 52 mm, respectively, with grouting effectively sealing fractures to depths of 1.71–3.92 m, as validated by multi-parameter monitoring. By integrating microscale material modification with macroscale structural optimization, this study provides a systematic and replicable solution for enhancing the stability of soft rock roadways under demanding geo-environmental conditions. Soft rock roadways, due to their characteristics of being rich in expansive clay minerals and having well-developed microfractures, make traditional support difficult to ensure roadway stability, so there is an urgent need to develop new active control technologies. This paper takes the 3205 Material Drift in Xin’an Coal Mine as the engineering background and adopts an integrated method combining micro-mesoscopic experiments, theoretical analysis, and field tests. The soft rock instability mechanism is revealed through micro-mesoscopic experiments; a high-performance grouting material added with redispersible latex powder is developed, and a “material–structure” synergistic tiered thick anchoring reinforced load-bearing technology is proposed; the technical effectiveness is verified through roadway surface displacement monitoring, anchor cable axial force monitoring, and borehole televiewer. The study found that micron-scale fractures of 0.89–20.41 μm develop inside the soft rock, and the total content of kaolinite and illite reaches 58.1%, which is the intrinsic root cause of macroscopic instability. In the test area of the new support scheme, the roof subsidence is about 10 mm and the rib convergence is about 52 mm, which are significantly reduced compared with traditional support; grouting effectively seals rock mass fractures in the range of 1.71–3.92 m. This synergistic control technology achieves systematic control from micro-mesoscopic improvement to macroscopic stability by actively modifying the surrounding rock and optimizing the support structure, significantly improving the stability of soft rock roadways. Full article

New arylbenzofuran derivatives were designed, synthesized, and evaluated as potential inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Five hybrid compounds (31–35) feature a 2-phenylbenzofuran core linked via a heptyloxy spacer to an N-methylbenzylamine moiety, to enhance interactions within the active site of BChE. Biological evaluation revealed that brominated derivatives 34 and 35 showed the highest cholinesterases (ChE) inhibition compared to their chlorinated analogs, with compound 34 showing the highest activity for both AChE (IC₅₀ = 27.7 μM) and BChE (IC₅₀ = 0.7 μM). These compounds proved to be non-cytotoxic and demonstrated significant antioxidant activity in SH-SY5Y cells exposed to hydrogen peroxide (H₂O₂), highlighting their potential to mitigate oxidative stress: a key pathological factor in Alzheimer’s disease. Structural activity analysis suggests that bromine substitution at position 7 and the presence of a seven-carbon linker are critical for dual ChE inhibition and selectivity towards BChE. ADMET prediction indicates favorable pharmacokinetic properties, including drug-likeness and oral bioavailability. Overall, these findings highlight the potential of the 2-arylbenzofuran as a promising scaffold for multitarget-directed ligands in Alzheimer’s disease therapy. Full article

The epiphytic community of Laminaria hyperborea, dominated by red algae, is typically discarded during industrial processing despite its potential as a source of high-value natural products. This study aims to valorize this underutilized biomass by characterizing its secondary metabolites and evaluating the biological activities of its major bromophenols. A combined chromatographic workflow enabled the isolation and structural elucidation of five bromophenols (1–5), including one previously undescribed compound (5). Among these, compound 4 exhibited the strongest cytotoxicity against the acute myeloid leukemia (AML) cell line MOLM-13 (EC₅₀ = 6.23 μM) and induced pronounced apoptotic features. When tested on two normal cell lines (NRK and H9c2) and in zebrafish larvae, it showed moderate toxicity at higher concentrations, indicating a reasonable selectivity window. In contrast, compound 5 was more toxic to normal cells than to MOLM-13 in vitro, while showing no acute toxicity in zebrafish; however, interpretations are preliminary due to compound purity. Bromophenols 1–4 were also tested for antioxidant activity, with 4 being the most potent (ABTS EC₅₀ = 22.1 μM), although this did not translate into protection against doxorubicin-induced cardiotoxicity. Additionally, non-targeted UHPLC-QTOF MS/MS analysis tentatively identified nine additional bromophenols and provided an estimation of their origin species within the epiphytic assemblage. Full article

An organophilic composite membrane, ZIF-67@PDMS, was fabricated to enhance the isolation of natural aromatic compounds. The as-prepared composite membrane was characterized using SEM, EDS, FTIR, XRD, and contact angle measurement. In comparison to pure PDMS, ZIF-67@PDMS, featuring a loading capacity of 2.5 wt% of PDMS and a membrane thickness of 15 μm, demonstrated markedly improved separation performance for the characteristic aroma compounds of strawberries, namely linalool, benzaldehyde, and ethyl acetate. Under optimal conditions, the permeation fluxes of the three compounds were 628.02 mg∙m⁻²∙h⁻¹, 294.82 mg∙m⁻²∙h⁻¹, and 254.14 mg∙m⁻²∙h⁻¹, along with separation factors of 26.48, 7.94, and 6.32, respectively. ZIF-67@PDMS was then employed to isolate aromatic compounds from freshly squeezed strawberry juice. By backfilling the permeate, both the variety and the content of aromatic compounds in strawberry concentrate were notably restored, and its aroma profile also closely resembled that of fresh strawberry juice. Full article

Skin photoaging, marked by structural and functional changes, is mainly caused by long-term ultraviolet (UV) exposure. This study sought to create hydroxytyrosol (HT)-loaded soluble microneedles (HT MNs) and thoroughly assess their anti-photoaging effects and underlying mechanisms in vitro and in vivo. The optimized HT MNs, featuring tips with 10% HT + 5% hyaluronic acid (HA) and a backing layer of 10% polyvinyl pyrrolidone (PVP), demonstrated robust mechanical strength (withstanding an axial force of 10 N without fracture), adequate penetration depth (>200 μm), and efficient skin self-recovery post-removal. In vitro, HT MNs notably boosted cell viability, reduced reactive oxygen species (ROS) levels, and suppressed senescence-associated β-galactosidase (A-β-Gal) expression in UVA-exposed human skin fibroblasts (HSF). In vivo, in a UVA + UVB-irradiated mouse model, HT MNs significantly enhanced skin hydration and elasticity, increased collagen density (confirmed by Masson staining), decreased malondialdehyde (MDA) content, and elevated the activities of glutathione (GSH), catalase (CAT), and glutathione peroxidase (GSH-Px). Western blot analysis further revealed that HT MNs upregulated the expression of collagen type I alpha 1 (COL1A1), elastin (ELN), hyaluronan synthase 2 (HAS2), and filaggrin (FLG), while downregulating matrix metalloproteinase 1. Overall, these findings suggest that HT MNs effectively mitigate UV-induced photoaging through antioxidant, anti-senescence, and extracellular matrix (ECM)-regulating mechanisms, underscoring their potential as a novel transdermal anti-photoaging therapy. Full article

Optical pressure sensors offer the advantages of high sensitivity, immunity to interference, and suitability for use in extreme environments. Based on the defect-immune, unidirectional transmission characteristics of valley photonic crystals (VPCs) and the refractive-index modulation of germanium under different pressures, we designed a topological ring resonator pressure sensor based on germanium VPCs. The shift of the resonance peak in the optical communication wavelength range with respect to pressure magnitude is studied to realize a pressure-sensing function. The results show that within the range of 0–10 GPa, the wavelength of the single resonance peak of the topological ring resonator pressure sensor shifts from 1580 nm to 1489 nm as the pressure increases. The sensor’s maximum detection sensitivity is 24.34 nm/GPa, and the transmittance across the bandwidth remains consistently above 0.85, with a maximum of 0.97. The germanium-based topological ring resonator pressure sensor features a compact structure with a size of 7.5 μm × 6.5 μm. It can be manufactured using existing nanofabrication technology and will have broad application prospects in the field of integrated photonic chips. Full article

Characterizing tight reservoirs is challenging due to the complex pore structure and strong heterogeneity at various scales. Current digital rock physics often struggles to reconcile high-resolution imaging with representative sample sizes, and 3D digital cores are frequently used primarily as visualization tools rather than predictive, computable platforms. Thus, a clear methodological gap persists: high-resolution models typically lack macroscopic geological features, while existing 3D digital models are seldom leveraged for quantitative, predictive analysis. This study, based on a full-diameter core sample of a single lithology (gray-black shale), aims to bridge this gap by developing an integrated workflow to construct a high-fidelity, computable 3D model that connects the micro–nano to the macroscopic scale. The core was scanned using high-resolution X-ray computed tomography (CT) at 0.4 μm resolution. The raw CT images were processed through a dedicated pipeline to mitigate artifacts and noise, followed by segmentation using Otsu’s algorithm and region-growing techniques in Avizo 9.0 to isolate minerals, pores, and the matrix. The segmented model was converted into an unstructured tetrahedral finite element mesh within ANSYS 2024 Workbench, with quality control (aspect ratio ≤ 3; skewness ≤ 0.4), enabling mechanical property assignment and simulation. The digital core model was rigorously validated against physical laboratory measurements, showing excellent agreement with relative errors below 5% for key properties, including porosity (4.52% vs. 4.615%), permeability (0.0186 mD vs. 0.0192 mD), and elastic modulus (38.2 GPa vs. 39.5 GPa). Pore network analysis quantified the poor connectivity of the tight reservoir, revealing an average coordination number of 2.8 and a pore throat radius distribution of 0.05–0.32 μm. The presented workflow successfully creates a quantitatively validated “digital twin” of a full-diameter core. It provides a tangible solution to the scale-representativeness trade-off and transitions digital core analysis from a visualization tool to a computable platform for predicting key reservoir properties, such as permeability and elastic modulus, through numerical simulation, offering a robust technical means for the accurate evaluation of tight reservoirs. Full article

During batch soldering, assembly of micro image sensor modules, initial random pose, and feature partially occlude target micro-component image, leading to issues of missed and erroneous detection, and low 3D spatial positioning accuracy due to cross-depth-of-field detection errors in microscopic vision. This paper proposes Small object-YOLO11-Cross-Depth-of-field Positioning (SO-YOLO11-CDP), an instance segmentation-based approach for precision cross-depth-of-field positioning micro-component. First, an improved Small object-YOLO11 (SO-YOLO11) image segmentation algorithm is designed. By incorporating a coordinate attention mechanism (CA) into segmentation head to enhance localization of micro-targets, the backbone uses non-stride convolution to preserve fine-grained feature, while target regression performance is boosted via Efficient-IoU (EIoU) loss combined with normalized Wasserstein distance (NWD). Subsequently, to further improve spatial position detection accuracy in cross-depth-of-field detection, a calibration error compensation model for image Jacobian matrix is established based on pinhole imaging principles. Experimental results indicate that SO-YOLO11 achieves 16.1% increase in precision, 4.0% increase in recall, and 9.9% increase in mean average precision (mAP0.5) over baseline YOLO11. Furthermore, it accomplishes spatial detection accuracy superior to 6.5 μm for target micro-components. The method presented in this paper holds significant engineering application value for high-precision spatial position detection of micro image sensor components. Full article

Three-dimensional biomaterial scaffolds with controlled geometry and surface nanoarchitecture are essential for advancing polymer processing strategies in tissue engineering. Conventional electrospinning generates nanofibrous structures but has limited ability to reproduce defined three-dimensional shapes or achieve high pattern fidelity. This study aimed to develop a scalable processing method for producing biodegradable scaffolds with precisely controlled microstructure and geometry using phase separation–assisted electrospray. Poly (lactic acid) microcapsules with tunable diameters and porous nanofibrous surfaces were fabricated under controlled humidity and deposited onto conductive molds to obtain two- and three-dimensional scaffold shapes. The manufacturing process required only simple electrospray equipment and static molds, without mechanically complex collectors or moving stages. The resulting scaffolds replicated mold features with resolutions down to 200 μm and achieved thickness up to 600 μm. The nanofibrous microcapsule surfaces supported strong adhesion and metabolic activity of HepG2 cells, while cellular penetration into deeper scaffold regions remained limited to approximately 80 μm. These findings indicate that electrospray-mediated microcapsule deposition is a practical polymer-processing approach that integrates nanofibrous surface formation with mold-defined shaping, offering a reproducible and scalable method for fabricating structurally precise and biologically compatible three-dimensional scaffolds. Full article

This study developed high-performance anti-flashover silicone coatings using sol–gel-synthesized CaCO₃/SiO₂ hierarchical fillers optimized via L₁₆(4⁵) orthogonal design. The optimal filler (Sample 5) was prepared under 70 vol% ethanol, with nTEOS:nCaCO₃ = 1:1 and 0.2 mol/L NH₃·H₂O, at 45 °C, for 18 h, featuring covalent Si-O-Ca bonding, a dual-scale microstructure (2–4 μm CaCO₃ cores + 20–40 nm SiO₂ nodules), a 14.44 m²/g specific surface area, and bimodal porosity (8–80 nm). Composite C7 (30 wt% filler, 3 wt% KH-570, 1:2 resin-to-filler ratio) achieved superhydrophobicity (a 153° contact angle via Cassie-Baxter stabilization), ultrahigh electrical insulation (3.20 × 10¹⁴ Ω·cm volume resistivity, 1.60 × 10¹³ Ω surface resistivity), and robust mechanical properties (Shore 3H hardness, 5B adhesion). Standardized IEC 60507:2020 tests showed that C7’s flashover voltages (14.8 kV for KMnO₄, 14.3 kV for NaCl/KMnO₄, 13 kV for NaCl) exceeded that of neat silicone resin (NSR) and conventional CaCO₃-filled composite (SR-CC) by >135%. Additionally, C7 retained superhydrophobicity after 500 h UV aging and maintained a 124° contact angle after 12 months of outdoor exposure. The superior performance stems from synergistic hierarchical topology, tortuous discharge paths, and interfacial passivation. This work establishes a microstructure-driven design paradigm for grid protection materials in harsh environments. Full article