Search Results (1,014)

Motivated by the seminal discoveries in graphene, the exploration of novel physical phenomena in alternative two-dimensional (2D) materials has attracted tremendous attention. In this work, through theoretical investigation using first-principles calculations, we reveal that Mo-intercalated ${\mathrm{CrI}}_3$ bilayer exhibits ferromagnetic semiconductor behavior with a small easy-plane magnetocrystalline anisotropy energy (MAE) of 0.618 meV/Cr(Mo) between (100) and (001) magnetizations. The spin–orbit coupling (SOC) opens a narrow band gap at the Fermi level for both magnetization orientations with nonzero Chern number for realizing the quantum anomalous Hall effect (QAHE) in the former and with trivial topology in the latter. The small MAE implies the efficient experimental manipulation of magnetization between distinct topologies through an external magnetic field. Our findings provide compelling evidence that the QAHE in this system originates from the quantum spin Hall effect (QSHE), driven by intrinsic magnetism under broken time-reversal symmetry. These unique properties position Mo-intercalated ${\mathrm{CrI}}_3$ as a promising candidate for tunable spintronic applications. Full article

Two-dimensional (2D) van der Waals (vdW) magnetic materials have emerged as a frontier in condensed matter physics and materials science, offering unprecedented opportunities for next-generation spintronic technologies. This review examines the synthesis, properties, and transport phenomena of 2D magnetic materials, with particular emphasis on their integration into spintronic devices. A comprehensive historical overview of magnetic materials is provided, tracing the evolution of intrinsic ferromagnetism in the 2D limit, highlighting key materials such as Cr₂Ge₂Te₆, Fe₃GeTe₂, and CrI₃. Special attention is devoted to the fundamental magnetic properties—including magnetic anisotropy, Curie temperature, and spin polarization—that underpin their functional performance. Major synthesis strategies are evaluated, including chemical vapor deposition, micromechanical exfoliation, and molecular beam epitaxy, focusing on scalability, interface control, and material purity. Furthermore, hallmark transport phenomena are discussed, such as giant magnetoresistance, the quantum anomalous Hall effect, spin–orbit torque, and the role of exchange bias and skyrmions in vdW heterostructures. Throughout the review, current limitations, unresolved questions, and emerging research directions are identified that will accelerate the deployment of 2D magnetic materials in flexible, reconfigurable, and quantum spintronic systems. This work aims to guide ongoing experimental and theoretical efforts and articulate a vision for advancing the field toward device-level implementation. Full article

Beta-gallium oxide (β-Ga₂O₃) is a semiconductor with an ultra-wide bandgap, high optical transparency, and excellent electrical properties, which can be finely tuned for a wide range of electronic devices. This study optimized the process conditions for fabricating β-Ga₂O₃ thin films with desired electrical characteristics. β-Ga₂O₃ films were deposited on (100) Si substrates via RF magnetron sputtering with varying O₂ flow rates and post-annealed at temperatures ranging from 600 °C to 800 °C. The structural and electrical properties of the films were analyzed using X-ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), and Hall effect measurements. The XRD results confirmed the formation of nanocrystalline β-Ga₂O₃, with variations in peak intensities and shifts observed based on O₂ flow rates. The films exhibited carrier concentrations exceeding 5 × 10²² cm⁻³, mobilities ranging from 50 to 115 cm²/Vs, and resistivity around 1 × 10⁻⁶ Ω⋅cm. This study demonstrates that the electrical properties of β-Ga₂O₃ thin films can be modulated during the deposition and post-annealing processes. The ability to control these properties underscores the potential of β-Ga₂O₃ for advanced applications in high-performance high-power devices and optoelectronic devices such as deep ultraviolet photodetectors. Full article

Historic and cultural towns in China are crucial carriers of vernacular heritage, yet many unlisted historic buildings remain highly vulnerable to urbanization and fragmented governance. This study takes Xiangzhu Town in Zhejiang Province as a case study and develops a multidimensional evaluation framework—integrating value, morphology, and risk—to identify conservation priorities and guide adaptive reuse. The results highlight three key findings: (1) a spatial pattern of “core preservation and peripheral renewal,” with historical and artistic values concentrated in the core, scientific value declining outward, and functional diversity emerging at the periphery; (2) a morphological structure characterized by “macro-coherence and micro-diversity,” as revealed by balanced global connectivity and localized hotspots in space syntax analysis; and (3) differentiated building risks, where most assets are low to medium risk, but some high-value ancestral halls show accelerated deterioration requiring urgent action. Based on these insights, a collaborative framework of “graded management–classified guidance–zoned response” is proposed to align systematic restoration with community-driven revitalization. This study demonstrates the effectiveness of the value–morphology–risk approach for small historic towns, offering a replicable tool for differentiated heritage conservation and sustainable urban–rural transition. Full article

In this study, high-conductivity W-doped Ga₂O₃ thin films were successfully fabricated by directly depositing a composition of Ga₂O₃ with 10.7 at% WO₃ (W:Ga = 12:100) using electron beam evaporation. The resulting thin films were found to be amorphous. Due to the ohmic contact behavior observed between the W-doped Ga₂O₃ film and platinum (Pt), Pt was used as the contact electrode. Current-voltage (J-V) measurements of the W-doped Ga₂O₃ thin films demonstrated that the samples exhibited significant current density even without any post-deposition annealing treatment. To further validate the excellent charge transport characteristics, Hall effect measurements were conducted. Compared to undoped Ga₂O₃ thin films, which showed non-conductive characteristics, the W-doped thin films showed an increased carrier concentration and enhanced electron mobility, along with a substantial decrease in resistivity. The measured Hall coefficient of the W-doped Ga₂O₃ thin films was negative, indicating that these thin films were n-type semiconductors. Energy-Dispersive X-ray Spectroscopy was employed to verify the elemental ratios of Ga, O, and W in the W-doped Ga₂O₃ thin films, while X-ray photoelectron spectroscopy analysis further confirmed these ratios and demonstrated their variation with the depth of the deposited thin films. Furthermore, the W-doped Ga₂O₃ thin films were deposited onto both p-type and heavily doped p⁺-type silicon (Si) substrates to fabricate heterojunction diodes. All resulting devices exhibited good rectifying behavior, highlighting the promising potential of W-doped Ga₂O₃ thin films for use in rectifying electronic components. Full article

Extreme ultraviolet (EUV) pellicles must withstand intense thermal stress during exposure due to their limited heat dissipation, which results from their ultrathin geometry and the vacuum environment within EUV scanners. To address this challenge, we investigated the crystalline phase-dependent emissivity of nanometer-thick molybdenum disilicide (MoSi₂) membranes. Membranes exhibiting amorphous, hexagonal, and tetragonal phases were independently prepared via controlled annealing, and their thermal radiation properties were evaluated using heat-load testing under emulated EUV scanner conditions. The Hall effect measurements revealed distinct variations in carrier density and mobility across phases, which were theoretically correlated with emissivity using the Lorentz–Drude model. The results demonstrate that emissivity increases in the hexagonal phase due to increased carrier density and reduced scattering, offering improved thermal radiation performance. These findings establish the phase engineering of conductive silicides as a viable strategy for enhancing radiative cooling in EUV pellicles and offer a theoretical framework applicable to other high-temperature nanomaterials. Full article

This study investigates the influence of post-deposition thermal annealing temperature on the crystal structure, chemical composition, and electrical performance of solution-processed indium oxide (In₂O₃) thin films. Based on thermogravimetric analysis (TGA) of the precursor solution, annealing temperatures of 350, 450, and 550 °C were adopted. The resulting In₂O₃ films were characterized using ultraviolet–visible (UV–Vis) spectroscopy, atomic force microscopy (AFM), Raman spectroscopy, and Hall-effect measurements to evaluate their optical, morphological, crystalline polymorphism, and electrical properties. The results revealed that the film annealed at 450 °C exhibited a field-effect mobility of 4.28 cm²/V·s and an on/off current ratio of 2.15 × 10⁷. The measured hysteresis voltages were 3.11, 1.80, and 0.92 V for annealing temperatures of 350, 450, and 550 °C, respectively. Altogether, these findings indicate that an annealing temperature of 450 °C provides an optimal balance between the electrical performance and device stability for In₂O₃-based thin-film transistors (TFTs), making this condition favourable for high-performance oxide electronics. Full article

The degradation of the electronic properties of semiconductor materials and electronic devices under neutron irradiation is a critical issue for the development of electronic systems intended for use in nuclear and thermonuclear energy facilities. This study presents a methodology for real-time measurement of the electrical parameters of semiconductor structures during neutron irradiation in a high-flux reactor environment. A specially designed irradiation fixture with an electrical measurement system was developed and implemented at the WWR-K research reactor. The system enables simultaneous measurement of electrical conductivity and the Hall effect, with automatic temperature control and remote data acquisition. The sealed fixture, equipped with radiation-resistant wiring and a temperature control, allows for continuous measurement of remote material properties at neutron fluences exceeding 10¹⁸ cm⁻², eliminating the limitations associated with post-irradiation handling of radioactive samples. The technique was successfully applied to the two different InGaAs-based heterostructures, revealing distinct mechanisms of radiation-induced modification: degradation of mobility and carrier concentration in the InGaAs quantum well structure on GaAs substrate, and transmutation-induced doping effects in the heterostructure on InP substrate. The developed methodology provides a reliable platform for evaluating radiation resistance and optimizing materials for magnetic sensors and electronic components designed for high-radiation environments. Full article

The development of electromechanical linear actuators (EMLAs) aims at compactness, energy efficiency, and high reliability. Conventional design methods often rely on costly prototypes and individual considerations of mechanics, electromagnetics, and control dynamics. This leads to long development cycles, inadequate treatment of nonlinear effects, and suboptimal performance. To address these challenges, our paper introduces a novel hybrid design methodology, integrating Analytical Modeling, Finite Element Analysis (FEA), Genetic Algorithms (GAs), and targeted experiments. Analytical Modeling provides rapid sizing, FEA combined with a GA refines geometry, and targeted experiments quantify nonlinear effects (friction, wear, thermal variability, and dynamic resonances). Unlike conventional methods, the integration is performed within iterative loops, using empirical data to refine simulation assumptions. As a result, development time is reduced by 30% and nonlinear effects are precisely addressed. The method is demonstrated on an automotive-grade EMLA. Its design is based on a claw-pole Permanent Magnet Stepper Motor, a trapezoidal lead screw, and an open-loop control with Hall effect end-position detection. After applying the method, the EMLA delivers more than 40 N of push force and achieves 600,000 actuations under the required conditions, making it suitable for various applications. Full article

We report high-resolution, cavity-enhanced direct frequency comb Fourier transform spectroscopy of cold acetylene (C₂H₂) molecules in a planar supersonic jet expansion. The experiment is based on a near-infrared frequency comb with a 300 MHz effective repetition rate, matched to a high-finesse enhancement cavity traversing the jet. The rotational and translational cooling of acetylene was achieved via expansion in argon carrier gas through a slit nozzle. By interleaving successive mode-resolved spectra measured at different comb repetition rates, we retrieved full absorption line profiles. Spectroscopic analysis reveals sharp, Doppler-limited transitions corresponding to a jet core rotational temperature below 7 K. Frequency comb and cavity stabilization were achieved through active Pound–Drever–Hall locking and mechanical vibration damping, enabling a spectral precision better than 2 MHz, limited by the vibrations induced by the pumping system. The demonstrated sensitivity reaches a minimum detectable absorption of 7.8 × 10⁻⁷ cm⁻¹ over an 18 m effective path length in the jet core. This work illustrates the potential of cavity-enhanced direct frequency comb spectroscopy for precise spectroscopic characterization of cold supersonic expansions, with implications for studies in molecular dynamics, reaction kinetics, and laboratory astrophysics. Full article

This study constructed an integrated underwater pipeline monitoring system, which combines pipeline posture sensing modules and pipeline leakage detection modules. The proposed system can achieve the real-time monitoring of pipeline posture and the comprehensive assessment of pipeline damage. By deploying pipeline posture sensing and leakage detection modules in array configurations along an underwater pipeline, information related to pipeline posture and flow variations is continuously collected. An array of inertial sensor nodes that form the pipeline posture sensing system is used for real-time pipeline posture monitoring. The system measures underwater motion signals and obtains bending and buckling postures using posture algorithms. Pipeline leakage is evaluated using flow and water temperature data from Hall sensors deployed at each node, assessing pipeline health while estimating the location and area of pipeline damage based on the flow values along the nodes. The human–machine interface designed in this study for underwater pipelines supports automated monitoring and alert functions, so as to provide early warnings for pipeline postures and the analysis of damage locations before water supply abnormalities occur in the pipelines. Underwater experiments validated that this system can precisely capture real-time postures and damage locations of pipelines using sensing modules. By taking flow changes at these locations into consideration, the damage area with an error margin was estimated. In the experiments, the damage areas were 8.04 cm² to 25.96 cm², the estimated results were close to the actual area trends (R² = 0.9425), and the area error was within 5.16 cm² (with an error percentage ranging from −20% to 26%). The findings of this study contribute to the management efficiency of underwater pipelines, enabling more timely maintenance while effectively reducing the risk of water supply interruption due to pipeline damage. Full article

This study examines the effects of laser pulse duration on the structural, morphological, optical, and gas-sensing characteristics of ${\mathrm{Al}}_2{\mathrm{O}}_3$/AgO thin films deposited on glass substrates using pulsed laser deposition (PLD). Pulse durations of 10, 8, and 6 nanoseconds were achieved through optical lens modifications to control both energy density and laser spot size. X-ray diffraction (XRD) and atomic force microscopy (AFM) analyses showed a distinct reduction in both crystallite and grain sizes with decreasing pulse width, along with significant improvements in surface morphology refinement and film compactness. Hall effect measurements revealed a transition from n-type to p-type conductivity with decreasing pulse width, demonstrating increased hole concentration and reduced carrier mobility attributed to grain boundary scattering. Furthermore, current-voltage (I-V) characteristics demonstrated improved photoconductivity under illumination, with the most pronounced enhancement observed in samples prepared using longer pulse durations. Gas sensing measurements for ${\mathrm{NO}}_2$ and ${\mathrm{H}}_2$S revealed enhanced sensitivity, improved response/recovery characteristics at 250 °C, with optimal performance achieved in films deposited using shorter pulse durations. This improvement is attributed to their larger surface area and higher density of active adsorption sites. Our results demonstrate a clear relationship between laser pulse parameters and the functional properties of ${\mathrm{Al}}_2{\mathrm{O}}_3$/AgO films, providing valuable insights for optimizing deposition processes to develop advanced gas sensors. Full article

In order to provide fire-scene parameters for fire protection design and data support for fire safety management of waiting halls in high-speed railway stations, this study systematically investigated the combustion characteristics of single, two, and three massage chairs using an industrial calorimeter. The results showed the following: The change in heat release rate in the growth stage of the massage chairs’ combustion tests was consistent with the t² fast fire (with a growth coefficient of 0.04689). The maximum HRR was 1.2 MW for the single-massage-chair combustion test, 2.5 MW for the two-massage-chairs combustion test, and 3.5 MW for the three-massage-chairs combustion test. In the full-scale massage chairs combustion test, setting a 6.0 m fire isolation zone could effectively serve the functions of fire prevention and heat insulation. Considering a certain safety margin, and with a safety factor of 1.5 adopted, it is recommended that a fire isolation zone with a width of 9.0 m be used in the waiting halls of high-speed railway stations, which provides a direct, actionable design basis for engineering practice. Full article

Aluminothermic reduction is gaining renewed interest as an alternative processing route for the circular economy. Aluminium is produced electrochemically in the Hall–Héroult process with minimal CO₂ emissions if electricity is sourced from non-fossil fuel energy sources. The Al₂O₃ product from the aluminothermic reduction process can be recycled via hydrometallurgy, with leaching as the first step. NaAlO₂ is a water-leachable compound that forms a pathway for recycling Al₂O₃ with hydrometallurgy. In this work, a suitable slag formulation is applied in the aluminothermic reduction of manganese ore to form a Na₂O-based slag of high Al₂O₃ solubility to effect good alloy–slag separation. The synergistic effect of added chromium metal as a collector metal is illustrated with an increased alloy yield at 68%, from 43% without added Cr. The addition of small amounts of carbon reductant to MnO₂-containing ore ensures rapid pre-reduction to MnO. This approach negates the need for a pre-roasting step. The alloy and slag chemical analyses are compared to the thermochemistry-predicted phase chemistry. The alloy consists of 57% Mn, 18% Cr, 18% Fe, 3.4% Si, 1.5% Al, and 2.2% C. The formulated slag exhibits high Al₂O₃ solubility, enabling effective alloy–slag separation, even at an Al₂O₃ content of 55%. Full article

We have carried out detailed theoretical and numerical calculations and developed a physics-based model for quantitatively describing the Landau levels of several pseudospin-1 structures with a flat band and a finite bandgap in their electronic-energy spectrum under a strong and uniform magnetic field. We have investigated the Landau-level-based dynamics, as well as the corresponding eigenstates, for gapped graphene, a dice lattice with both a zero and finite bandgap and, eventually, for the Lieb lattice, which represents a separate type of square lattice with a very special non-symmetric (elevated) location of the flat band which intersects the conduction band at its lowest point. Exact analytical consideration of Landau-level states has been performed and explained when dealing with all types of considered lattices. Our model could be further generalized for treating cases with an arbitrary position for the flat band between the valence and conduction bands. Our current results have direct implications for a deep-level investigation of the quantum Hall effect, as well as other magnetic and topological properties of these novel materials. Full article