Accepted
, , Received Date: 2025-09-07
Abstract +
In order to develop a rapid and cost-effective new method to produce periodic microstructures on solid surfaces, and help to understand the physical mechanism of the enhancement of laser-induced breakdown spectroscopy (LIBS) signals induced by periodic surface microstructures, in this work, spherical copper powder with about 74 μm in diameter is used to imprint semispherical periodic surface microstructures on polyvinyl chloride (PVC) sheets under a pressure of 15 T. A platinum conducting layer about 100 nm in thickness is coated on the PVC surface by using a vacuum sputter coater and then nickel plates with the replicated microstructures on one surface are prepared using electroplating method. The signal enhancement effect induced by micro-structured surface in LIBS is experimentally observed and compared with that achieved by using flat surface nickel plate, the temperature and electron density of the induced plasma are measured according to Boltzmann plot method and the Stark broadening of Hα line of hydrogen. By systematically analyzing these results, it is concluded that the main physical mechanism of the signal enhancement in LIBS caused by the hemispherical periodic surface microstructure is due to the increased surface area of the sample that can be irradiated by the laser beam, leading to an increase in the mass of the ablated sample material when compared with that of a flat surface irradiated by the same laser beam. Comparative analysis is also conducted with experimental phenomena and signal enhancement mechanisms of using cylindrical periodic surface microstructures with a certain depth (20 μm diameter, 15 μm depth and 40 μm period). It is found that the depth of the microstructure helps to achieve better signal enhancement effects. This provides useful references for subsequent microstructure parameter design in the future. Finally, lead in aqueous solution samples is detected with surface-enhanced LIBS (SENLIBS) technique, while Pb I 405.78 nm line is selected as the analytical line. In comparison with flat nickel substrates, 23-fold detection sensitivity and slightly improved signal reproducibility can be achieved using nickel substrates with hemispherical periodic surface microstructures. The results indicate that nickel plates with hemispherical periodic surface microstructure show better analytical performance than flat nickel plates in elemental analysis of aqueous solution samples by SENLIBS.
, , Received Date: 2025-09-03
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To reveal the correlation between the anisotropy of electromagnetic absorbing metastructure and the radar cross section (RCS) of its curved components, the typical anisotropic hexagonal honeycomb (HH) metastructure and isotropic sheet gyroid (SG) metastructure are systematically studied. Both conformal mapping and non-conformal mapping methods are employed for designing the conformal curved components. These designs are compared using simulation and microwave anechoic chamber testing to evaluate their RCSs. The results indicate that the RCS of isotropic sheet gyroid curved components is insensitive to design methods, exhibiting strong design method and absorbing robustness; however, the RCS of anisotropic hexagonal honeycomb curved components exhibits strong dependence on design methods. Compared with anisotropic structures, metastructures with electromagnetic isotropy have significant advantages in achieving wide-angle and robust low-scattering characteristics of curved components, with lower dependence on design and processing. This study provides important design guidance for developing high-performance radar low-scattering components.
, , Received Date: 2025-07-29
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Microwave-induced thermoacoustic imaging, as an emerging biomedical imaging technique, combines the high contrast of microwave imaging with the high spatial resolution of ultrasound imaging. Microwave-induced thermoacoustic microscopy, as an important branch of this technology, retains these advantages while possessing the ability to visualize finer tissue characteristics. However, traditional raster scanning mechanisms introduce interference into microwave field distribution due to mechanical motion, thus necessitating multiple signal average to maintain signal-to-noise ratio. Additionally, the idle time during motor movement results in extended single-scan durations, limiting its practical applications. To address these limitations, this work proposes a rapid imaging system based on one-dimensional galvanometer scanning. The system employs a hybrid galvanometer-translation stage architecture and an optimized scanning strategy to minimize microwave field interference, reduce the number of signal averages and shortens the idle time, ultimately achieving more than a tenfold improvement in imaging speed. A specially designed timing control algorithm ensures the precise synchronization of microwave excitation, galvanometer motion, and ultrasound detection, while the reconstruction algorithm suitable for the optimizing scanning method effectively corrects distortions generated in the scanning process. The system performance is assessed through phantom and ex vivo tissue experiments. Resolution tests show hundred-micrometer resolution along all three axes (332 μm × 324 μm × 79 μm), while contrast and depth imaging experiments confirm its ability to clearly distinguish targets with different conductivities, achieving an effective detection depth of at least 10 mm in tissue. Early tumor mimicking experiments further demonstrate the ability of the system to identify lesion boundaries, preliminarily revealing its potential for rapid tumor margin assessment. This approach maintains the imaging quality of microwave-induced thermoacoustic microscopy while enhancing imaging efficiency and system stability, thereby laying a crucial foundation for advancing the technology from laboratory research to clinical applications.
, , Received Date: 2025-10-16
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Achieving a balance between low density, high strength, and good ductility remains a major challenge in the development of structural materials. Ti-based bulk metallic glasses (BMGs) have attracted considerable attention due to their exceptionally high specific strength. However, the intrinsic strength–plasticity trade-off has hindered their practical applications. Based on a quasicrystal-derived structural heredity and minor-element microalloying, this work realizes a synergistic enhancement of specific strength and plasticity in Ti-based BMGs. The resulting ((Ti40Zr40Ni20)72Be28)97Al3 BMGs demonstrate an ultrahigh specific strength of 5.34 × 105 N·m·kg–1, establishing a new record for Ti-based BMGs, along with a plastic strain of 13%, breaking through the traditional strength–plasticity limitation of BMGs. Structural analyses show that Al microalloying effectively inherits and modulates the short-range order derived from quasicrystalline structures, thereby achieving an observed synergistic enhancement in both strength and plasticity. This work provides new insights into composition design and lightweight structural applications of Ti-based BMGs.
, , Received Date: 2025-09-04
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Due to its unique physical and chemical properties, hydrogen plasma is the preferred gas for cleaning reaction chambers. To better understand the transport and diffusion mechanism in hydrogen plasma, this work presents a two-dimensional fluid model by using COMSOL simulation software, and systematically investigates the characteristics of a radio-frequency inductively coupled remote hydrogen plasma source under varying discharge and geometric parameters. The results show that input power primarily affects electron density rather than electron temperature. This phenomenon may result from the balancing mechanism between theionization rate and the loss rate in steady state discharges. The pressure has an opposite effect on the plasma in the driven region compared with that in the spatial afterglow region. As the pressure rises, the electron density in the driven region increases gradually, while the electron density in the spatial afterglow region decreases gradually. This may be due to the shift from non-local to local electron kinetics as the pressure rises. Increasing input power effectively enhances hydrogen radical density and diffusion flux, indicating that high power facilitates the transport of hydrogen radicals into the spatial afterglow region. However, elevating operating pressure has a similar effect while reducing hydrogen radical density in the spatial afterglow region. Furthermore, under fixed discharge conditions, increasing geometric parameters appropriately promotes the generation of higher and more uniform hydrogen radical densities within the afterglow region.
Abstract +
Chiral magnons are collective spin excitations whose dispersions break momentum inversion symmetry, $\omega(\boldsymbol{k}) \neq \omega(-\boldsymbol{k})$, leading to intrinsically nonreciprocal spin-wave propagation. This built-in directionality offers new opportunities for spin information transfer, thermal-spin interconversion, and low-dissipation nonreciprocal microwave devices, in a manner complementary to but distinct from topological magnonics. This review develops a unified framework for chiral magnons, covering symmetry-breaking mechanisms, material realizations, transport responses and many-body non-Hermitian dynamics, and evaluates routes toward room-temperature, device-relevant platforms. The discussion is based on symmetry analysis, model Hamiltonians and spin-wave theory, in combination with first-principles calculations and recent spectroscopic and transport measurements. The microscopic origins of chiral magnons are organized into three interrelated aspects, spin-orbit coupling (SOC)-driven Dzyaloshinskii-Moriya interactions (DMI) in non-centrosymmetric magnets and interfaces, altermagnetism in the weak SOC regime without DMI, and the spin space group (SSG) framework. On this basis, representative materials such as CrSb, α-MnTe, RuO2 and MnF2 are compared in terms of energy scales, coherence, momentum anisotropy and experimental visibility, clarifying how magnon splittings and lifetimes are reflected in direction-dependent spin Seebeck, spin Nernst and thermal Hall signals. The review further summarizes bulk-gap and Berry-curvature induced chiral edge states, enhancement of nonreciprocity via chiral spin pumping and cavity-magnon hybrids, and non-Hermitian features arising from multiparticle damping and gain-loss competition. Furthermore, remaining challenges, such as the stability of physical properties at room temperature, quantitative calibration of spectral and transport properties, as well as many-body competition also outlined. Finally, the possible strategies based on SSG-guided materials screening, multi-modal metrology and geometry phase engineering toward efficient spin logic, THz isolators and quantum routing based on chiral magnons also proposed.
, , Received Date: 2025-09-15
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, , Received Date: 2025-09-02
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In recent years, topological valley physics with the degrees of freedom of valley pseudospin has attracted great attention. The topological valley boundary states in phononic crystals have important application prospects in efficient guidance and sensing for acoustic and elastic wave due to their unique transmission characteristics with backscattering immunity. However, the coupling effect of the valley edge states in multi-layer topological heterostructure is still a challenge in the elastic system due to the complicated multi-mode polarization of elastic waves. In this work, a valley topological phononic crystal plate with a multi-layer heterostructure is constructed to explore the multi-mode interference characteristics of the valley edge states based on the analogy of elastic wave quantum valley Hall effect. The coupling behavior of valley edge states for the out-of-plane polarized elastic wave in multi-layer topological heterostructure is systematically studied. By adjusting the layer numbers of the topological heterostructures, the formation mechanism and regulation law of coupled valley edge states for elastic wave in finite size multi-layer heterogeneous structures are revealed. Furthermore, through topological transmission calculations, the multi-mode interference effect of coupled valley edge states for elastic wave is achieved and its transmission robustness is well verified. Finally, as an application example, an elastic topological wavelength demultiplexing device is designed based on the multi-mode interference effect of valley edge state. By utilizing the difference in coupling wavelengths of elastic valley edge states at different coupling frequencies, directional separation of incident elastic waves in defect resistant channels is achieved, which can be used as a prototype model for the novel application of elastic wavelength demultiplex device. This work provides a new paradigm for the manipulation of elastic wave topological transport, which is also expected to promote the practical design of new multifunctional elastic wave coupling and sensing devices.
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, , Received Date: 2025-09-05
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Phase change fibers, as an advanced functional material for human body thermal management, have significant potential for practical applications. However, current research systems face critical limitations: traditional phase change fibers prepared via wet spinning and electrospun phase change fiber films encounter insufficient thermal insulation due to their structural compactness deficiencies, thereby failing to effectively prevent body heat loss in cold environments. To tackle this technical challenge, this work breaks through traditional material system limitations by innovatively employing electrospinning technology to integrate polyethylene glycol (PEG) into polyacrylonitrile (PAN) fiber systems. We successfully fabricate fluffy-tructured phase change fibers that integrate both phase change thermoregulation and thermal insulation functions using the principle of non-solvent-induced phase separation. The internal porous structure of the fluffy fibers constructs an effective cold protection layer, exhibiting an ultra-low thermal conductivity of 0.0395 W/m·K. At the same time, the PEG phase change componentprovides a high latent heat of 80.6 J/g, achieving a synergistic effect of temperature regulation and thermal insulation. The material exhibits excellent structural and thermal stability: maintaining stable phase change performance after 500 thermal cycles and exhibiting exceptional thermal reliability up to 300 ℃. Even above the phase change melting point, the material effectively prevents leakage of the phase change component. Furthermore, it possesses sufficient mechanical properties to withstand various deformations such as bending, compression (668.7 Pa), and stretching (253.5 kPa) without structural collapse. Practical application evaluations further demonstrate that the material’s cold protection performance significantly exceeds that of natural cotton. This study not only provides an innovative strategy for fabricating integrated “heat storage-thermal insulation” fibers, but also conceptually expands the design dimensions of phase change fibers in thermal management, offering important solutions and theoretical guidance for developing high performance wearable cold-protection materials.
, , Received Date: 2025-10-09
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Ferroelectric thin films and their device applications have drawn wide attentions since the 1990s. However, due to the critical size effect, ferroelectric thin films cannot maintain their ferroelectric properties as their thickness decreases to the nanometer size or one atomic layer, posing a significant challenge to the development of related nano-electronic devices. With a naturally stable layered structure, two-dimensional materials possess many advantages such as high-quality and smooth interface without dangling bonds, no interlayer interface defects, and the ability to maintain complete physical and chemical properties even at limited atomic thickness. Thus, it is gradually realized that two-dimensional materials are a good hotbed for the two-dimensional ferroelectricity. CuInP2S6, α-In2Se3, WTe2, and other intrinsic ferroelectric 2D materials have been reported successively while artificially stacked sliding ferroelectrics such as t-BN have also emerged, which expands the types of 2D ferroelectric materials and opens a new avenue for the further miniaturization and flexibility of ferroelectric electronic devices. This article reviews the recent research progress of two-dimensional ferroelectric materials, discusses their compositional characteristics, structural features and property modulation, and also prospects their application potential and future research hotspots.
, , Received Date: 2025-11-09
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The mass of the atomic nucleus, as one of the fundamental physical quantities of the atomic nucleus, plays an important role in understanding and researching the structure of the atomic nucleus and nuclear reactions, the basic interactions between nucleons. However, accurately predicting the mass of nuclei far from the β stability line remains a huge challenge. Based on the machine-learning-refined mass model, the newly measured atomic nucleus masses since 2022, the residual proton-neutron interaction ($\delta V_{pn}$), and the α-decay energy of heavy nucleus are studied. It is found that: (1) For the 23 newly measured atomic nuclei, the root mean square deviations obtained by the machine-learning-refined mass models are between 0.51 and 0.58 MeV, which are significantly lower than the 3.275, 1.058, 0.752, and 0.785 MeV given by the liquid droplet model (LDM), Weizsäcker-Skyrme-4 (WS4), finite-range droplet model (FRDM), and Duflo-Zucker (DZ), respectively. (2) The $\delta V_{pn}$ of the atomic nucleus with N = Z obtained from machine-learning-refined mass models is consistent with the latest experimental data. (3) The root mean square deviations of the α-decay energy of heavy nuclei obtained from the machine-learning-refined mass models have also been significantly reduced. Furthermore, by using the Bayesian model average approach to consider the results of different machine-learning-refined mass models, a more accurate prediction can be obtained. These results demonstrate that the machine-learning-refined mass models possess good extrapolation capabilities and can provide useful insight for further researches. The datasets presented in this paper, are openly available at https://doi.org/10.57760/sciencedb.j00213.00246 .
, , Received Date: 2025-09-22
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In recent years, two-dimensional (2D) ferroelectric materials have attracted widespread interest due to their ultrathin geometry, high stability, and switchable polarization states. Ferroelectric tunnel junctions (FTJs) made from 2D ferroelectric materials exhibit exceptionally high tunnel electroresistance (TER) ratios, making them leading candidates for next-generation non-volatile memory and logic devices. However, advancing FTJ technology depends on overcoming the critical challenge of precisely controlling quantum tunneling resistance. Therefore, this study proposes a strategy of interfacial work function engineering, which actively modulates the band alignment of a heterostructure through ferroelectric polarization switching, induces a reversible metal-insulator transition in the barrier layer, and modulates TER. Using a van der Waals heterostructure composed of Al2Te3/In2Se3 as a model system, we demonstrate through first-principles calculations that the strategic manipulation of interfacial work functions can induce a reversible metal-insulator transition in the barrier, thereby drastically changing the tunneling conductance. Further analysis indicates that a work function mismatch between the two ferroelectric materials causes varying degrees of interfacial charge transfer, thereby triggering a metal-insulator transition in the van der Waals ferroelectric heterostructure as the external electric field is reversed. Non-equilibrium transport simulations reveal an unprecedented TER ratio of 2.69×105%. Our findings not only highlight Al2Te3/In2Se3 as a promising platform for high-performance FTJs but also establish a universal design strategy for engineering ultrahigh TER effects in low-dimensional ferroelectric memory devices. This work opens new avenues for developing energy-efficient, non-volatile memory with enhanced scalability and switching characteristics.
, , Received Date: 2025-09-21
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Tunneling Magnetoresistance (TMR) sensors have emerged as a leading technology in high-performance magnetic sensing, distinguished by their high sensitivity, low power consumption, and miniaturization. To address the evolving demands of cutting-edge applications like biomagnetic imaging and smart grid monitoring, continuous performance enhancement is crucial. This review systematically outlines the key strategies for optimizing TMR sensors, focusing on thin-film material engineering and sensitive microstructure design. Material advancements are dissected along two paths: developing high-sensitivity systems via MgO barriers and composite free layers, and creating wide-linear-range systems through anisotropy engineering, including both perpendicular (PMA) and in-plane (IMA) configurations, as well as dynamic methods like electric-field and strain modulation. Structurally, we highlight innovations such as vortex-state MTJs and magnetic flux concentrators to enhance linearity and sensitivity, alongside advanced noise modulation techniques that effectively suppress low-frequency 1/f noise. The practical impact of these optimizations is evidenced by TMR sensors now capable of measuring magnetocardiograms (MCG) outside shielded environments and providing high-accuracy current sensing in smart grids. Future development is directed towards novel material systems that balance high sensitivity with a wide linear range, the realization of monolithic three-axis vector sensors, and the deep integration of TMR technology with artificial intelligence for smart sensing systems. This work provides a comprehensive reference for advancing TMR sensor technology and its applications in high-precision magnetic field detection.
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