Search Results (53)

In this study, a stepwise strategy was adopted to regulate and control the complexing agent system of the cyanide-free alkaline zinc–nickel (Zn-Ni) electroplating solution. A Zn-Ni coating containing a quaternary complexing agent was successfully prepared on the surface of low-carbon steel to enhance the flatness and corrosion resistance of the coating. The investigated complexing agents included triethanolamine (TEA), tetraethylenepentamine (TEPA), ethylene diaminetetraacetic acid (EDTA), and potassium sodium tartrate (PST). By fixing other parameters and testing the four complexing agents one by one, TEA was finally determined to be the best single complexing agent. This substance can effectively stabilize the metal-ion deposition process. The synergistic effects of TEPA, EDTA and PST were systematically studied, and the independent contributions of each complexing agent to performance were clarified. This design enables performance differences to be directly attributed to the inherent characteristics of each complexing agent category. The surface morphology of the sample was characterized by scanning electron microscopy (SEM). The cross-sectional morphological characteristics were analyzed by a laser scanning confocal microscope (LSCM). The chemical composition and phase composition of the samples were determined by X-ray diffraction (XRD), while the corrosion behavior of the samples was studied by electrochemical techniques, including electrochemical impedance spectroscopy (EIS) and Tafel curves. Characterization shows that when the molar ratio of EDTA to PST is 1:4 and TEA and TEPA are used in combination, the grain size of the coating is smaller, the surface is smoother, and the number of surface micropores is significantly reduced compared with coatings prepared by other complexation systems, thereby improving the flatness and corrosion resistance of the coating. Full article

Surface roughness at the nanometer scale limits the optical performance of reflective components for X-ray and extreme ultraviolet beam shaping. While sub-nanometer roughness can be achieved by polishing planar substrates, it remains challenging for continuous three-dimensional topographies fabricated by grayscale direct-write lithography in polymer resists. In this work, mm-long linear grayscale slopes are introduced as a calibration platform to distinguish between form, waviness, and roughness contributions. Process optimization reduces artifacts such as gray-value discretization and stitching, while replication into PMMA combined with the TASTE process enables a reduction of intrinsic roughness below 2 nm. Laser scanning confocal and atomic force microscopy are used as complementary techniques to assess surface quality across spatial scales. The results provide insight into the origin of roughness in novolak-based resists and its evolution through the fabrication chain, highlighting material limitations and paths toward smooth polymer optics with sub-nanometer roughness. Full article

The widespread occurrence of microplastics (MPs) and nanoplastics (NPs) in wastewater treatment plants (WWTPs) has raised notable ecological concerns. This study investigated the multi-level impacts of polystyrene (PS) MPs and NPs on activated sludge in sequencing batch reactors (SBRs). Although long-term exposure to PS particles (up to 200 mg/L MPs and 50 mg/L NPs) did not compromise the macro-performance of the SBRs (with COD, NH₄⁺-N, and TP removal efficiencies remaining >90%), the physical and biological integrity of the sludge was significantly altered. Sludge volume index (SVI) analysis revealed a decline in settleability, particularly under NP stress, which was corroborated by laser scanning confocal microscopy (LSCM) and transmission electron microscopy (TEM) observations showing the internalization of NPs into microbial cells. Physiologically, PS NPs induced higher levels of reactive oxygen species (ROS) and lactate dehydrogenase (LDH) release, indicating substantial oxidative stress and membrane damage. Furthermore, high-throughput sequencing and qPCR analysis demonstrated that PS particles reshaped the microbial community, enriching the antibiotic-resistant genus Acinetobacter and various antibiotic resistance genes (ARGs) such as sulII and tetG. Notably, PS NPs exhibited a more pronounced effect on ARG dissemination than MPs, even at lower mass concentrations, by facilitating horizontal gene transfer (HGT) through increased cell membrane permeability. These findings elucidate the distinct toxicological mechanisms of NPs in biological treatment systems and highlight their role as catalysts for the environmental spread of antibiotic resistance. Full article

The complexity of micrometer-scale pore-throat structures in sandstone reservoirs strongly controls the occurrence state and mobilization degree of residual oil after water-flooding. To clarify the differences in residual oil occurrence between pure oil-zone and transition-zone reservoirs and their microscopic controlling mechanisms, sandstone samples were collected from the SII oil layer group, which belongs to the Upper Cretaceous Yaojia Formation, in the Nanqi area of the Daqing Oilfield, northern Songliao Basin, NE China, and were investigated. Mercury intrusion capillary pressure (MICP), two-dimensional nuclear magnetic resonance (2D NMR), laser scanning confocal microscopy (LSCM), micro-computed tomography (micro-CT), X-ray diffraction (XRD), wettability measurement and fractal analysis were integrated to systematically characterize the pore-throat architecture, mineral composition, seepage capacity, and residual oil occurrence of the two reservoir types. The results show that the pore-throat radius distributions are mainly unimodal. In the pure oil-zone samples, the pore-throat distribution is highly consistent with the corresponding permeability contribution curve, whereas evident deviations occur in some transition-zone samples. Large and medium pore throats exert the most significant control on seepage capacity, and the difference in fractal characteristics is mainly reflected by D1, the fractal dimension of large pore throats. The transition-zone reservoirs generally exhibit moderate to strong water-wet characteristics. Owing to the development of fine pore throats and strong capillary forces, water is prone to retention within pore-throat spaces, resulting in pronounced water-blocking and Jamin effects. After water-flooding, the pure oil-zone reservoirs exhibit lower residual oil saturation, with residual oil occurring mainly in a bound state; in contrast, the transition-zone reservoirs show higher residual oil saturation and relatively high proportions of free and semi-bound residual oil. Mineral composition further modifies pore-throat complexity and residual oil occurrence. D1 is negatively correlated with feldspar content, indicating that increased feldspar content helps improve the pore-throat structure, but positively correlated with clay mineral content, suggesting that clay minerals enhance structural complexity. In the transition-zone reservoirs, kaolinite and illite–smectite mixed-layer minerals are relatively well developed. Their velocity-sensitive and water-sensitive effects readily induce pore-throat blockage and increased flow resistance, which are important causes of residual oil enrichment and difficult oil mobilization in the transition zone. Full article

This study presents a unified topological and multifractal framework for the characterization of leaf surface complexity in Theobroma grandiflorum. By combining laser scanning confocal microscopy (LSCM)-derived three-dimensional profilometry with Minkowski functionals and multifractal analysis, we quantitatively distinguished the structural organization of adaxial and abaxial surfaces beyond conventional morphological descriptions. The analysis of the Minkowski functionals revealed distinct connectivity regimes and threshold-dependent transitions, indicating differences in surface topology and percolation behavior. These findings were further supported by multifractal spectra, which exhibited a broader distribution of singularities for the abaxial surface, reflecting increased heterogeneity and structural complexity. The introduction of the normalized differential parameter ΔP proved to be an effective strategy for directly quantifying morphological asymmetry, while radar plots enabled an integrated visualization of multivariate descriptors. From a physical perspective, the observed differences are consistent with the functional specialization of leaf surfaces, where the abaxial side exhibits greater structural complexity associated with gas exchange and environmental interaction, while the adaxial surface remains more compact and protective. Overall, the proposed approach advances the application of fractal and topological methods to biological systems, offering a scalable and transferable framework for the analysis of complex natural surfaces. This methodology opens new perspectives for studies in plant morphology, taxonomy, and environmental adaptation, aligning with the broader scope of fractal and fractional analysis in complex systems. Full article

Sparganium stoloniferum tubers (SL), known medicinally as Sparganii Rhizoma, are commonly considered superior at the winter-harvest stage, when they show the traditional quality traits of heavy weight and firm texture. However, the developmental basis of this quality phenotype remains insufficiently understood. This study aimed to determine how tissue organization, cell-wall architecture, starch deposition, and related transcriptional patterns are associated with winter-harvest quality in SL. By comparing SL at different developmental stages, we found that maturation was accompanied by reduced moisture content, increased tuber density, higher parenchyma cell density, progressive cell-wall thickening, and marked starch accumulation. Laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) observations further revealed thickened multilamellar cell walls and abundant clustered or compound-like starch bodies in mature SL. Starch isolated from mature SL displayed an A-type crystalline pattern, short-range order, and high gelatinization and pasting temperatures, indicating an ordered and thermally stable starch matrix. Cell-wall Fourier-transform infrared spectroscopy (FTIR) and solid-state nuclear magnetic resonance (NMR) analyses showed a predominantly polysaccharide-rich framework with subtle maturation-associated changes in aromatic- and methoxy-associated wall signals. Transcript-guided pathway analysis, supported by reverse transcription quantitative polymerase chain reaction (RT–qPCR)validation, suggested developmental shifts in carbohydrate metabolism, lipid-related metabolism, and gibberellin-associated transcriptional patterns. Together, these findings indicate that winter-harvest quality in SL is associated with coordinated tissue consolidation, cell-wall maturation, starch deposition, and transcriptional reprogramming, providing a structural and molecular framework for understanding the traditional firm-texture trait of S. stoloniferum. Full article

Differential enrichment of shale oil hydrocarbon fractions exerts a fundamental control on the spatial distribution of “sweet spots” and the efficiency of unconventional resource recovery. This study investigates the continental shales of the Upper Es4 Member in the Dongying Sag, Bohai Bay Basin, through an integrated analytical framework combining Laser Scanning Confocal Microscopy (LSCM), Scanning Electron Microscopy (SEM), and high-pressure mercury intrusion. By moving beyond qualitative observations, we characterize the micro-scale partitioning of light and heavy fractions and establish a deterministic hierarchy of controlling factors. Our results indicate the following. (1) Mineral composition functions as a “primary geochemical filter,” where carbonate minerals exhibit a preferential adsorption affinity for light fractions (≤C₁₈), while clay minerals facilitate the selective retention of heavy components (>C₁₈). (2) Pore–throat architecture acts as a “secondary mobility modulator.” A statistically significant linear correlation (R² = 0.72, p < 0.05) was identified between mean pore diameter and the light-to-heavy fluorescence ratio, suggesting that interconnected macropores in carbonate laminae provide low-resistance conduits for light oil accumulation, whereas isolated mesopores in argillaceous matrices promote heavy-component sequestration. (3) Thermal maturity (Ro) drives a progressive shift in the light-to-heavy ratio, enhancing oil fluidity and regulating the transition from adsorption-dominated to migration-dominated enrichment. This study clarifies the lithofacies-dependent coupling mechanisms between mineral diagenesis and pore-scale fractionation, providing a semi-quantitative conceptual model for shale oil sweet-spot prediction in complex lacustrine basins. Full article

Understanding the way samarium–cobalt alloys solidify at varying cooling rates and the regularities in alloying element distribution is crucial for optimizing subsequent homogenization and annealing processes, leading to an enhancement in the overall quality of the product. The study investigates the effects of rapid water-cooled copper mold (600 °C/min), medium-speed copper mold (100 °C/min), and slow furnace cooling (10 °C/min) on the microstructural evolution, element distribution, and phase transformation of samarium–cobalt (Sm-Co) alloys. The results of the research show that the phase transition temperatures obtained via differential scanning calorimetry (DSC) closely matched those observed in situ by high-temperature laser scanning confocal microscopy (HT-LSCM). Higher cooling rates resulted in notable dendritic refinement and reduced precipitate size. Elemental analysis revealed that Co and Fe exhibited negative segregation, whereas Sm, Cu, and Zr showed positive segregation, with segregation intensity increasing alongside the cooling rate. The principal phases identified included Cu-rich and Zr-rich constituents, the matrix phase, and a gray phase morphologically distinct from the matrix. These correspond to the (Sm, Co, Fe, Cu, Zr)₅ phase, (Sm, Zr)(Co, Fe, Cu)₃ phase, Sm₂(Co, Fe, Cu, Zr)₁₇ phase, and Sm(Co, Fe, Cu, Zr)₇ phase. The phase constitution remained consistent across different cooling rates. Full article

Background: The treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections is extremely challenging due to its antibiotic resistance, and the combination of plant active ingredients with antibiotics represents a potential strategy to address this issue. Methods: We determined the combinatorial relationship between baicalin (BA) and kanamycin (KM) using the checkerboard dilution method. The antibacterial activity of the baicalin–kanamycin (BA/KM) combination was evaluated through growth curve determination assays and scanning electron microscopy (SEM). The effects of the BA/KM combination on the cell membrane and cell wall of MRSA were analyzed using reactive oxygen species (ROS) detection assays, intracellular protein leakage experiments, alkaline phosphatase (AKP) activity assays, laser scanning confocal microscopy (LSCM) observations, and molecular docking simulations. The antibiofilm activity and related mechanisms of the BA/KM combination were elucidated via crystal violet staining, MTT assay, phenol-sulfuric acid method, congo red staining, staphyloxanthin determination assays, and quantitative real-time polymerase chain reaction (qPCR). The safety of the BA/KM combination was assessed through hemolytic activity analysis, and its anti-MRSA efficacy was evaluated on lettuce. Results: BA/KM combination showed a synergistic antibacterial effect on MRSA USA300. Mechanistic studies revealed that BA may interact with amino acid residues of peptidoglycan synthetase PBP2a to hinder peptidoglycan synthesis, thereby facilitating KM penetration through the cell wall. Subsequently, BA binds to amino acid residues of the membrane transporter NorA, leading to disruption of cell membrane homeostasis and enhancing KM’s ability to induce intracellular ROS accumulation in MRSA. Furthermore, the BA/KM combination reduced MRSA biofilm formation by 77.85% and decreased the metabolic activity of biofilm cells by 42.93% through inhibiting the synthesis of biofilm components EPS and PIA. Additionally, this combination suppressed the synthesis of staphyloxanthin and downregulated the expression of agrA and agrC genes. When 1/8 MIC BA was combined with 1/4 MIC KM, the count of MRSA on lettuce surfaces was reduced by 0.88 log CFU/cm², an effect comparable to that of 0.2% (v/v) hydrogen peroxide. Conclusions: According to these findings, the BA/KM combination may offer a promising option for enhancing antibacterial efficacy through synergism, reducing antibiotic usage concentrations, and limiting MRSA transmission in fresh agricultural products. Full article

Coatings that are tolerant of poor surface preparation are often used for rapid, real-time maintenance of aging steel surfaces. In this study, a modified epoxy (EP) anti-rust coating was proposed, utilizing methyl gallate (MG) as a rust conversion agent, graphene oxide (GO) as an active functional material, and epoxy resin as the film-forming material. The anti-rust mechanism was investigated using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), laser scanning confocal microscopy (LSCM), and the scanning vibration electrode technique (SVET). The results demonstrated that over a period of 21 days, the impedance of the coating increases while the corrosion current density decreases with prolonged soaking time. The coating exhibited a maximum impedance of 2259 kΩ, and a lower corrosion current density of 8.316 × 10⁻³ A/m², which demonstrated a three-order magnitude reduction compared to the corrosion current density observed in mild steel without coating. LSCM demonstrated that MG can not only penetrate the tiny gap between the rust particles, but also effectively convert harmful rust into a complex. SVET showed a much more uniform current density distribution in the micro-zones of mild steel with the anti-rust coating compared to uncoated mild steel, indicating that the presence of GO not only enhanced the electrical conductivity of the coating, but also improved the structure of the coating, which contributed to the high performance of the modified epoxy anti-rust coating. This work highlights the potential application of anti-rust coating in the protection of metal structures in coastal engineering. Full article

The CASTRIP process is an innovative method for producing flat rolled low-carbon and low-alloy steel at very thin thicknesses. By casting steel close to its final dimensions, enormous savings in time and energy can be realized. In this paper, an ultra-high-strength low-alloy corrosion-resistant steel was produced through the CASTRIP process. Microstructure and properties were investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), laser confocal microscopy (LSCM), electron backscattered diffraction (EBSD), and tensile testing. The results show that the microstructure is mainly composed of polygonal ferrite, bainite ferrite, and acicular ferrite. The bainite ferrite forms parallel lath bundles nucleating at austenite grain boundaries, propagating perpendicularly into the parent grains. The acicular ferrite exhibits a cross-interlocked morphology preferentially nucleating at oxide/sulfide inclusions. Microstructural characterization confirms that the phase transformation of acicular ferrite and bainite ferrite introduces high-density dislocations, identified as the primary strengthening mechanism. Under the CASTRIP process, corrosion-resistant elements such as Cu, P, Sb, and Nb are completely dissolved in the matrix without grain boundary segregation, thereby contributing to solid solution strengthening. Full article

As the crucial core material in aluminum–plastic-laminated films, aluminum foil serves as a barrier and shaping element for lithium-ion battery soft packaging. However, its thinness, measuring only tens of microns, makes it susceptible to the formation of pinholes during the manufacturing process, which can significantly impact the barrier performance and properties of the aluminum–plastic-laminated film. The morphology and composition of foreign particles that lead to pinholes were analyzed using scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). Additionally, the formation mechanism and evolution law of pinholes were investigated using a laser scanning confocal microscope (LSCM). The results revealed that foreign particles responsible for pinholes originated from the inclusions in the aluminum alloy melt, filter aid particles from rolling oil, and environmental dust particles. To address this issue, potential strategies for controlling foreign particles were proposed. These included purifying the aluminum alloy melt, filtering the rolling oil, and maintaining a clean production environment. The simulated experiments showed that foreign particles were gradually embedded in the aluminum matrix during plastic deformation, leading to damage in the aluminum matrix. When the cumulative rolling reduction ratio exceeded 38%, the aluminum foil and foreign particles began to separate along the rolling direction, resulting in the formation of pinholes. The mechanism of uncoordinated deformation between foreign particles and aluminum foil was elaborated in detail. In addition, the simulation experiment indicated that once the cumulative reduction ratio surpassed 50%, the aspect ratio of the pinhole increased rapidly. When the cumulative reduction ratio increased to 83%, the pinhole began to gradually heal. Consequently, a quantitative relationship model between the pinhole area and the rolling reduction ratio was constructed. The pinhole evolution model enables a rough prediction of the actual pinhole area change and meets the requirements for engineering applications. This research provides both engineering applications and theoretical prediction approaches that can aid in the production of high-quality aluminum foil for lithium-ion battery soft packaging. Full article

Microplastics pose a significant environmental threat, and understanding their sources and generation mechanisms is crucial for mitigation efforts. This study investigates the effects of ultraviolet intensity, temperature, and relative humidity on the degradation of polyethylene terephthalate (PET) plastics and the subsequent formation of microplastic particles. PET samples were exposed to ultraviolet (UV) radiation under various environmental conditions using the SPHERE (Simulated Photodegradation via High Energy Radiant Exposure) accelerated weathering device at the National Institute of Standards and Technology (NIST). Attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) and laser confocal scanning microscopy (LSCM)/atomic force microscopy (AFM) were employed to characterize the chemical and morphological changes on the weathered surfaces. This study’s findings reveal that temperature and relative humidity significantly influence the rate of photodegradation and the characteristics of the generated microplastics. Higher temperatures and increased humidity accelerated the degradation process, leading to a higher abundance of microplastic particles. However, larger particles were observed at higher temperatures due to aggregation. These results underscore the importance of considering environmental factors when assessing the fate and transport of microplastics in the environment. Developing strategies to reduce plastic pollution and mitigate the generation of microplastics is essential for protecting ecosystems and human health. Full article

Nanoparticles play an important role in plant response to abiotic stresses including salt stress. In this study, the physiological and histological responses of CuO, ZnO, and CaO nanoparticle (NP) applications on callus tissues developed from two alfalfa lines (Erzurum and Muş) exposed to salt (NaCl) stress were evaluated. The NPs were synthesized from the extracts obtained from healthy walnut shells using the green synthesis approach and then characterized by Scanning Electron Microscopy (SEM) and X-ray diffraction analysis (XRD). The leaf explants were placed in an MS medium containing 4 mg L⁻¹ 2,4-D (2,4-dichlorophenoxyacetic acid), 50 mM NaCl, and 0.8 ppm of NPs for 1 month in the dark. CaO NP is determined to be more effective than CuO and ZnO in callus induction from leaf explants. Malondialdehyde (MDA) content was higher in the callus treated with 0.8 ppm CuO NP + 50 mM NaCl compared to other treatments. The callus induction stage, without salt treatments, showed the best results with 0.8 ppm CaO NPs for both H₂O₂ levels and peroxidase (POX) activity compared to the other NPs. The highest protein rate was obtained from the callus induction stage and callus formation stage after 50 mM treatment NaCl with 0.8 ppm CuO. The LCSM results displayed, under in vitro conditions, that the treatment of NPs can greatly suppress the negative effects of salt stress on calli samples. SEM analysis supported the results obtained by laser scanning confocal microscopy (LSCM) analysis. Our findings suggest that CuO, CaO, and ZnO NPs can offer a simple and effective method to protect alfalfa callus from NaCl stress severity. Furthermore, these NPs, particularly CaO, hold potential for broader application and should be evaluated under various abiotic conditions beyond salt stress. Full article

High toxicity is the main reason for the limited application of traditional corrosion inhibitors. Herein, it is critical to find a green, efficient, and long-term stable alternative substitute for the hazardous and conventional corrosion inhibitor. Ambrosia trifida L is widely distributed in fields and riverside wetlands as an invasive plant in China. According to the concept of turning waste into treasure, the extract of Ambrosia trifida L leaves (ATL) has the potential to address this issue due to its natural origin and abundant presence of heterocyclic organics. Therefore, ATL, as a green corrosion inhibitor, is prepared for the first time via a simple water-based extraction method. FT-IR (Fourier transform infrared spectroscopy) and UV-Vis (UV-visible) indicate that ATL extract contains abundant heterocyclic organics with conjugated structures, which exhibit the potential to become a high-efficiency inhibitor. Notably, the active sites of ATL molecules and their interaction with Q235 steel at the molecular/atomic level are revealed via theoretical calculations. The highest E_binding value observed for the major components in the ATL extract is 259.66 kcal/mol, implying a significant adsorption capacity. The electrochemical results verify that microdose ATL extract can prominently inhibit steel corrosion, and the highest inhibition efficiency (η) is 97.5% (1000 mg/L). Following immersion for 24 h, the η value is enhanced to 99.0%, indicating a reliable and long-term ATL extract protection film is formed on the steel surface in harsh acidic solutions. The results of the weight loss, SEM (scanning electron microscope), and LSCM (laser scanning confocal microscopy) are consistent with the above conclusions. Finally, this study anticipates providing theoretical support for developing novel green plant extract inhibitors and aiding in their application in industrial pickling environments. Full article