Search Results (1,570)

A lightweight and high-efficiency microwave-absorbing material was developed via an in situ solvothermal pyrolysis strategy by anchoring sphere-like Fe₃O₄ nanostructures onto bamboo-derived porous carbon (BPC). The resulting composites preserve the intrinsic anisotropic honeycomb architecture of bamboo while introducing uniformly distributed magnetic nanoparticles, enabling synergistic dielectric–magnetic loss. Electromagnetic parameters, alongside impedance matching, were successfully modulated through the optimization of precursor concentrations. Of the evaluated materials, BPC-0.9 stood out for its intense attenuation, recording an RL_min of −45.17 dB at a 1.8 mm thickness. Furthermore, a significant effective absorption bandwidth of 6.65 GHz was attained by the BPC-0.6 sample at only 2.2 mm. Several factors contribute to the boosted efficiency, starting with conductive and interfacial polarization losses paired with multiple scattering events. Furthermore, magnetic loss components, encompassing eddy current effects as well as natural and exchange resonances, play a pivotal role in optimizing the material’s response. Furthermore, radar cross-section (RCS) modeling reveals a substantial reduction of 19.9 dB·m², verifying the material’s viability for real-world stealth technologies. Our findings offer a straightforward methodology for fabricating magnetic carbon structures from biomass with adjustable dielectric responses, underscoring their potential in high-performance energy conversion and low-density microwave absorption. Full article

While spatially transmissive or reflective metasurfaces have achieved unprecedented wavefront control in free space, the paradigm shift toward on-chip waveguide-integrated architectures presents novel challenges for constructing compact and scalable photonic systems. Existing on-chip holographic schemes are typically constrained by the complexity of meta-atom structures, limited multiplexing capacity, and strict dependence on specific polarization states. This report comprehensively elucidates a novel on-chip metasurface architecture that relies exclusively on a unified detour phase modulation mechanism to achieve high-capacity, multi-channel holographic multiplexing. By deeply integrating a phase-displacement-joint displacement algorithmic framework with the simulated annealing global optimization algorithm, this design highly circumvents the necessity for complex anisotropic meta-atom geometries and the physical superposition of multiple phase mechanisms. Within an ultra-compact physical footprint of 55.55 × 55.55 μm², the architecture successfully achieves customized holographic reconstruction at specific far-field planes. When discrete TE modes in the visible spectrum are injected from orthogonal lateral directions, distinctly different target holograms are reconstructed in the far field without crosstalk. This mechanism establishes a robust four-wavelength, four-channel independent coding framework. The findings not only elucidate a simplified and highly scalable methodology for ultra-high-density on-chip displays but also provide profound theoretical guidance and technical support for cutting-edge applications such as augmented reality, secure optical communications, and high-density optical data storage. Full article

Acoustoelasticity provides the physical sensing principle for ultrasonic stress measurement. However, most existing formulations are restricted to isotropic media, simple stress conditions, and Cartesian coordinate systems, which limits their applicability in practical sensing scenarios involving curved and anisotropic structures. In this work, a general tensorial formulation of acoustoelasticity is developed based on the theory of incremental deformation. The proposed governing equations describe the motion of incremental displacement with explicit dependence on initial stress or strain, and are applicable to materials with arbitrary symmetry and general initial stress states. Owing to its coordinate-independent tensorial nature, the formulation can be expressed in any curvilinear coordinate system. To facilitate practical ultrasonic sensing applications, the general equations are further expanded in a cylindrical coordinate system for orthotropic materials. This enables the analysis of elastic wave propagation in curved structures such as pipelines, pressure vessels, and boreholes. The formulation establishes a direct relationship between initial stress and effective elastic properties, which determine wave velocities measurable by ultrasonic sensors, such as time-of-flight and phase velocity. The proposed approach provides a rigorous theoretical foundation for ultrasonic stress sensing and nondestructive testing, particularly for curved and anisotropic structures, and supports improved accuracy in sensor-based stress evaluation. Full article

The Rb₂Ca₃(SO₄)₄ compound was obtained by rapid cooling of the stoichiometric melt. The crystal structure was solved and refined using single crystal X-ray diffraction analysis (P2₁/c, a = 9.2847(9), b = 9.4094(6), c = 9.2917(8) Å, β = 114.646(1)°, V = 737.80(12) ų, R₁ = 0.051). The thermal behavior of Rb₂Ca₃(SO₄)₄ was investigated by high-temperature powder X-ray diffraction in the range 25–1000 °C. Thermal decomposition of the Rb₂Ca₃(SO₄)₄ phase occurs at 300 °C, forming Rb₂Ca₂(SO₄)₃ and CaSO₄. The decomposition is complete at 450 °C, and the mixture of Rb₂Ca₂(SO₄)₃ + CaSO₄ persists up to 890 °C. Homogenization of the phases occurs at 900 °C, resulting in the formation of the Rb₂Ca₃(SO₄)₄ compound again at 970 °C. A structural interpretation of this thermal phase transformation is presented, and the relationship between the crystal structures of Rb₂Ca₃(SO₄)₄ and Rb₂Ca₂(SO₄)₃ of the langbeinite structure type is demonstrated. Thermal expansion of Rb₂Ca₃(SO₄)₄ is highly anisotropic: α₁₁ = 23.9(4), α_b = 19.2(3), α₃₃ = 7.7(1), α_β = −1.9(7), α_V = 50.8(9) × 10⁻⁶ °C⁻¹ at 25 °C and α₁₁ = −7(2), α_b = 17(5), α₃₃ = 25(7), α_β = −1.1(1), α_V = 35(9) × 10⁻⁶ °C⁻¹ at 1000 °C. The anisotropy of the thermal expansion is described in comparison with the Rb₂Ca₃(SO₄)₄ crystal structure. The optical band gap for the Rb₂Ca₃(SO₄)₄ compound was determined to be 3.7 eV from absorption spectroscopy data. Full article

Since the first successful synthesis of borophene in 2015, this atomically thin boron allotrope has attracted extensive attention due to its polymorphic structures, metallic conductivity, and outstanding mechanical flexibility. As a new member of the two-dimensional (2D) materials family, borophene exhibits a unique triangular lattice with tunable hexagonal vacancies, leading to rich structural diversity and anisotropic physical properties. Recent breakthroughs in synthesis—particularly molecular beam epitaxy (MBE), chemical vapor deposition (CVD), and solvothermal-assisted liquid-phase exfoliation (S-LPE)—have significantly expanded the accessible structural phases and improved control over film quality and stability. Meanwhile, borophene’s distinctive combination of structural and electronic characteristics has enabled its rapid development in both energy and biomedical applications. In energy storage, borophene serves as a promising anode material for lithium/sodium-ion batteries and a lightweight medium for hydrogen storage and supercapacitors, owing to its metallic conductivity, high surface charge density, and large adsorption capacity. In biomedicine, borophene-based nanoplatforms exhibit excellent photothermal conversion efficiency, enabling multifunctional roles in cancer diagnosis and therapy. Despite these advances, several challenges—such as environmental instability, oxidation susceptibility, and limited scalable synthesis—continue to restrict practical implementation. Future progress will depend on chemical functionalization, surface passivation, and machine-learning-assisted materials design to achieve oxidation-resistant, large-area, and biocompatible borophene derivatives. This review summarizes recent advances in borophene synthesis, structural engineering, and multifunctional applications, while outlining key scientific challenges and future opportunities for the realization of borophene-based materials in next-generation energy and biomedical systems. Full article

High-performance flexible electronics require soft materials that combine mechanical robustness with efficient ionic conduction. In conventional ionogels, however, these requirements often conflict: dense networks improve strength but reduce the free volume and mobility needed for ion transport. This review provides a critical overview of recent progress in cellulose-based ionogels, with emphasis on design principles for decoupling mechanical and conductive properties. We discuss how cellulose precursors, crosslinking architectures (hydrogen bonding, covalent networks, and metal-ion coordination), and processing histories determine gel structure and mechanical integrity. We then highlight strategies that mitigate the trade-off, including precursor engineering, phase-separated networks, double-network architectures, crystallization-induced reorganization, and anisotropic assembly. Representative applications in flexible sensors, flexible energy-storage devices, and soft actuators are also summarized. This review offers a practical framework for designing cellulose-based soft functional materials with robust mechanics and sustained ionic conductivity. Full article

This paper examines the integration of three-dimensional (3D) printing and robotic fabrication in contemporary architectural design, with a focus on overcoming the technical limitations that constrain large-scale adoption. While additive manufacturing enables the production of complex geometries and customized structures, its standalone application remains limited by fixed build volumes, planar deposition, lack of tensile reinforcement, open-loop process control, and single-process extrusion. To address these constraints, the paper proposes a functional integration framework that systematically maps robotic fabrication capabilities onto these five critical limitations. Evidence from recent studies demonstrates that such integration has already led to measurable advances, including up to a 90-fold increase in printable volume through mobile robotic systems, robotically fabricated reinforcement systems (e.g., Mesh Mold) achieving post-crack behavior comparable to conventional reinforced concrete, and the implementation of closed-loop sensor-based process control to enhance interlayer bonding. Despite these achievements, interdisciplinary collaboration across architecture, structural engineering, materials science, and robotics remains largely fragmented and is predominantly confined to academic and pilot-scale projects, such as the ETH Zurich DFAB House. Regulatory progress is also limited, with only isolated code-compliant implementations under frameworks such as ICC-ES AC509 and ISO/ASTM 52939. Persistent barriers including high capital costs, loss of information in BIM-to-fabrication workflows, anisotropic material behavior, and the absence of long-term durability standards continue to restrict widespread adoption. These findings suggest that advancing robotic additive manufacturing in architecture requires not only technological innovation but also coordinated cross-disciplinary integration, standardized testing protocols, and harmonized regulatory frameworks. Full article

High-resolution images of non-cooperative spacecraft are essential for on-board autonomous operations. Hardware bandwidth limits and continuously changing observation distances mean that a practical super-resolution (SR) system must handle arbitrary, non-integer magnification factors without retraining, a setting known as arbitrary-scale SR (ASSR). Recent 2D Gaussian splatting (2DGS) methods represent image content with explicit anisotropic Gaussian primitives and render at any continuous coordinate, offering substantially faster inference than implicit neural representation (INR) approaches. Yet spacecraft imagery presents a structural mismatch for uniform 2DGS regression: the target occupies a small, densely structured region within a vast, featureless deep-space background, so a network that minimizes average reconstruction loss inevitably over-invests capacity in the irrelevant background and smears the fine edges of antennas and solar panels. We propose S³R-GS, a saliency-guided framework that embeds semantic spatial priors into the 2DGS pipeline at three levels: an encoder-level module that suppresses background noise before it reaches the splatting stage; a discrete Gaussian routing mechanism that assigns each spatial location to a semantically appropriate kernel group and reformulates Gaussian modeling as semantic prototype selection; and a saliency-weighted training strategy that concentrates the optimization gradient on the spacecraft target. Experiments on the SPEED and SPEED+ benchmarks show that S³R-GS achieves strong PSNR performance, competitive SSIM, and improved perceptual quality across scale factors from $\times 2$ to $\times 12$; additional ablation, extreme-lighting, and efficiency analyses further support the robustness and practicality of the proposed design. Full article

Composite hydrogen storage vessels exhibit pronounced anisotropy, multilayered winding architectures, and strong ultrasonic attenuation, which severely degrade the focusing accuracy and defect visibility of the conventional isotropic total focusing method (TFM). To address these challenges, this study proposes an enhanced TFM framework for defect inspection in composite hydrogen storage vessels by integrating anisotropic delay correction, Gray-code coded excitation, and coherence-weighted reconstruction. First, an anisotropic propagation delay model is established using forward ray tracing to compensate for beam deviation and focusing mismatch induced by the anisotropic winding structure. Then, Gray-code excitation and pulse compression are introduced to improve signal energy and echo detectability under high-attenuation conditions. Finally, coherence-weighted imaging is applied to suppress incoherent background noise and structural artifacts, thereby enhancing defect contrast and image readability. The proposed method is validated on hydrogen storage vessel specimens containing artificial defects, with CT results used as references. Experimental results show that, compared with conventional isotropic TFM, the proposed collaborative approach significantly improves defect imaging quality for defects of different sizes and depths. The signal-to-noise ratio is increased from 7.2, 12.8, 14.8, and 7.4 dB for isotropic TFM to 32.5, 29.9, 52.6, and 42.7 dB, respectively, for the combined anisotropic, coded-excitation, and coherence-weighted TFM. In addition, the defect depth estimation remains stable and agrees well with the CT references, yielding approximately 9.0–9.6 mm for shallow defects and 18.7–19.3 mm for deeper defects. These results demonstrate that the proposed method can effectively improve defect detectability, image contrast, and depth characterization for embedded delamination-like artificial defects in composite hydrogen storage vessels, providing a promising ultrasonic imaging strategy for thick-walled anisotropic composite pressure structures. Full article

Additive manufacturing (AM) has revolutionized industrial production. However, the repair of AM components remains a critical challenge due to their unique microstructural features. While repair approaches for conventionally manufactured alloys are well established, their direct transferability to AM parts remains largely unexplored due to the unique thermal history and anisotropic microstructure of additive components. This study investigates a novel repair and improvement strategy for Powder Bed Fusion–Laser Beam/Metal (PBF-LB/M)-fabricated AlSi10Mg components, combining Electrospark Deposition (ESD) for dimensional restoration with subsequent Ultrasonic Peening Treatment (UPT) for surface enhancement. Microstructure, porosity, surface roughness, hardness profiles, residual stresses, and corrosion behaviour were systematically characterized using SEM, optical microscopy, profilometry, Vickers microhardness testing, XRD, and electrochemical polarization tests. The results show that the ESD process is capable of producing coatings with excellent interfacial adhesion to the substrate, with an initial porosity of 3.6 ± 0.5%. The subsequent UPT induces a significant densification effect on the deposited material, reducing porosity by approximately 50% and increasing surface hardness by up to 48% in the upper region of the coating. Furthermore, XRD analysis reveals that UPT completely reverses the residual stress state from tensile (typical of the ESD process) to compressive in all measured directions, thereby improving the overall structural integrity. Ultimately, the combined ESD + UPT alters the electrochemical response of AlSi10Mg deposits, resulting in a nobler corrosion potential, albeit with a slightly higher corrosion current density. Full article

This study investigates how structural dimensionality affects the optoelectronic behavior of organic lead–halide hybrid perovskites. Using the chiral cation R-1-phenylethylammonium (PEA), which is known to be able to form both one-dimensional (1D) and two-dimensional (2D) lead–iodide frameworks, we synthesize 1D $\left(\mathrm{PEA}\right){\mathrm{PbI}}_3$ and 2D ${\left(\mathrm{PEA}\right)}_2{\mathrm{PbI}}_4$ compounds through tailored crystallization and deposition routes. X ray diffraction confirms structural purity, while ultraviolet photoelectron spectroscopy (UPS) provides insight into the electronic structure and photoresponse. Both materials exhibit a surface photo-voltage (SPV) under visible illumination, reaching a maximum work function shift of 1.5 eV for the 2D phase and 0.4 eV for the 1D phase in the thin-film samples. These results suggest that the 1D phase exhibits a reduced tendency for iodide-vacancy formation, which may result in a more stable response under visible illumination, accompanied by faster relaxation dynamics and more anisotropic charge transport. Overall, our findings highlight the central role of electronic confinement in shaping photoinduced processes in hybrid perovskites and support the consideration of structural dimensionality as a key design parameter for the design of next-generation optoelectronic materials. Full article

Synthetic Aperture Radar (SAR) target detection remains challenging due to coherent speckle corruption, weak-scattering targets with degraded structural cues, and cross-scale inconsistencies under anisotropic scattering. To tackle these challenges, this paper presents MSPaDet, a novel multi-scale phase-aware denoising detection framework that advances SAR target detection by deeply integrating phase coherence with multi-scale representation learning. The proposed method introduces explicit dual-tree complex wavelet transform decomposition to generate direction-selective complex sub-bands, enabling fine-grained sub-band modulation. Within the framework, an SCFRDeno module suppresses speckle-dominant responses while preserving high-frequency structures via phase-coherence-guided reweighting, and a PaSCA block further refines features through input-adaptive spatial focusing and region reweighting. Extensive experiments on public SAR detection benchmarks—including MSAR, SAR-Aircraft-1.0, and SARDet-100K—demonstrate that our approach consistently outperforms state-of-the-art methods in detection accuracy, robustness, and cross-scenario generalization, with moderate computational cost, showing promising potential for practical deployment in Earth observation and safety monitoring systems. Full article

Circular dichroism is at the core of chiral spectroscopy and polarization light manipulation. However, achieving metal-based devices with high efficiency, compactness, and easy integration in the near-infrared band remains a significant challenge. Traditional metal chiral microstructures, such as broken open rings, helical lines, or waveplates–polarizers I confirm., are limited to circular dichroism values below 50% due to their inherent ohmic losses, severely restricting practical applications. To overcome this bottleneck, this paper proposes a twisted double-layer plasmonic metasurface composed of two anisotropic metal metasurfaces. This design breaks the mirror symmetry of the structure by precisely controlling the in-plane twist angle between the layers, inducing strong coupling and interference effects in the chiral optical response. Simulation results show that this device achieves excellent multi-wavelength circular dichroism control. At a wavelength of 1660 nm, the circular dichroism value reaches 0.48, and it further increases to 0.84 at 2200 nm, significantly surpassing the performance limits of traditional metal structures. This work not only provides a simple and scalable design paradigm for high-performance chiral optical devices but also opens up new avenues for advanced applications such as chiral molecular sensing, polarization coding, and quantum optics in the near-infrared band. Full article

A generalized eigenvalue formulation is developed for the free vibration analysis of anisotropic rectangular plates with rotationally restrained edges using the finite integral transform method. For free vibration problems, casting the governing equations into a generalized eigenvalue problem is particularly advantageous because it enables the direct and systematic extraction of multiple natural frequencies and their associated mode shapes within a unified framework, while avoiding the need for assumed trial functions or solution searching near initial guesses. In the present study, a two-dimensional sine integral transform is introduced into the governing equation of anisotropic plates with bending-twisting coupling, and the mechanical description of rotationally restrained boundary conditions is incorporated simultaneously, thereby converting the original partial differential boundary value problem into a generalized eigenvalue problem. The corresponding analytical solution is then established through the finite integral transform framework. The accuracy and reliability of the proposed method are verified through comparisons with finite element results and published data. Based on the obtained analytical solution, the effects of boundary conditions, rotational stiffness coefficients, aspect ratio, and key stiffness components on the vibration characteristics of anisotropic rectangular plates are further examined. The present study provides an effective analytical framework for free vibration analysis of anisotropic plates with nonclassical rotational restraints and offers theoretical support for the dynamic design and optimization of advanced composite plate structures. Full article

The formation and growth of isolated domains during local switching by a biased tip of a scanning probe microscope in a (100) cut of a bismuth titanate Bi₄Ti₃O₁₂ single crystal were studied experimentally. The as-grown domain structure consists of two domain types: a-type (out-of-plane) and b-type (in-plane). Local switching of the a-type domain area leads to anisotropic growth of a hexagonal a-type domain (a-a switching) with 180° walls. The dependence of the domain size on the pulse duration during domain growth along the b-axis was considered in terms of the anisotropic current-limited domain wall motion. Local switching of the b-type domain area leads to formation of a hexagonal a-type domain (b-a switching) with 90° walls increasing in size linearly with the applied voltage. The dependence of the domain size on the pulse duration was measured over a wide range of humidities. The increase in the domain size at moderate humidity is attributed to the effect of the water meniscus. The decrease in the domain size at high humidity is attributed to backswitching under the action of the residual depolarization field, facilitated by a conductive water layer on the side surfaces of the sample. The obtained results provide useful insights into the domain kinetics of ferroelectrics with C₂ symmetry and can pave the way for the development of domain engineering techniques. The obtained results establish a direct relationship between local switching kinetics, crystallographic anisotropy, and environmental conditions. This provides the scientific community with a new framework for understanding domain wall motion in multiaxial ferroelectrics, which is essential for the development of stable and reliable domain-engineered devices. Full article