Physics

The development of thermochromic smart windows is a crucial topic for sustainable and energy-saving buildings. W-VO2 is a promising thermochromic material, as W doping lowers the phase transition temperature (Tc) to near room temperature, thereby improving its suitability for building smart window applications. However, W-doping compromises its luminous transmittance (Tlum) and solar energy modulation ability (ΔTsol). In this study, a W-VO2&PVP/PMMA/W-VO2&PVP multilayer structure was proposed to enhance Tlum and ΔTsol simultaneously. This configuration establishes a VO2 concentration gradient while utilizing PMMA as an interlayer to prevent mutual dissolution between the two VO2 composite layers. The Tlum of the W-VO2&PVP/PMMA/W-VO2&PVP composite film-based smart windows was increased by 16.29% (from 50.33% to 58.53%) compared with the W-VO2&PVP, and the solar modulation (ΔTsol) was increased 5.45% (from 15.76% to 16.62%). This enhancement is primarily attributed to the concentration gradient, which extends the effective propagation depth of light and forms a refractive index gradient, significantly enhancing the Tlum. Meanwhile, the deepened light penetration intensifies the localized surface plasmon resonance absorption, resulting in a higher ΔTsol. This study demonstrates that 0.22%–0.56% concentration-gradient engineering provides an efficient strategy for simultaneously improving Tlum and ΔTsol, offering valuable guidance for the development of energy-saving smart window materials.

Concrete-core cement mixing (CCM) piles are an effective ground improvement technique for soft soils, enhancing bearing capacity and material efficiency by introducing a stiff core. However, the mechanisms governing vertical bearing behavior, ground failure evolution, and the influence of key structural parameters remain insufficiently understood. A series of numerical models of CCM piles with varying core lengths and irregular cross-sectional configurations are established using a four-dimensional lattice spring model (4D-LSM). The load transfer mechanisms, the mobilization of shaft resistance, and settlement responses under vertical loadings are systematically investigated. The predicted load–settlement curves and failure patterns exhibit good agreement with laboratory model tests, demonstrating the accuracy and applicability of 4D-LSM. Parametric analyses indicate that core length is a dominant factor influencing bearing performance, with the most significant improvement achieved when the core length is 0.8–1.0 times the pile length. Bamboo-shaped piles significantly enhance shaft resistance by enlarging the pile–soil contact area, resulting in ∼40% increase in ultimate bearing capacity and reduced settlement compared with uniform-diameter piles. Properly designed stepped piles can maintain bearing capacity while reducing material consumption. Optimizing the core length and cross-sectional configuration can effectively enhance bearing performance while improving material efficiency, highlighting the sustainability potential of CCM piles in soft ground engineering.

We present the design and fabrication of an endcap-type Paul trap. The trap is designed for studies with Ca+ and Yb+. The design, fabrication process, and characterization are presented in detail, with a focus on trapping a single compensated ion at the rf node. A custom-built imaging system of NA = 0.14 and magnification of ≈22× performs close to the diffraction limit and resolves multi-ion clusters. Controlled ion loading and characterization of the trap are performed using 40Ca+. The experimentally determined quadrupole coefficient of the trap is ≈0.3, which is very close to the design value. The relative frequency shift along the spectroscopy beam due to excess micromotion is at the level of 3.5 × 10−18 for 40Ca+. Applications of this trap encompass single-ion-based optical frequency standards, tests of fundamental physics, the study of mesoscopic Coulomb clusters, and the controlled interaction of a single ion with co-trapped atoms.

High-quality micro-arc oxidation (MAO) coatings are a key research direction for aerospace titanium alloy TA15, but there is still a lack of research on the influence of adding different contents of TiN to the electrolyte on coating performance. To clarify the regulation mechanism of TiN doping on the microstructure and interface properties of MAO coatings, MAO coatings with TiN doping amounts of 0, 0.2, 0.5, and 1 g/L were prepared. Combined with macroscopic morphology observation, phase composition analysis, and energy dispersive spectrometer element distribution characterization, the influence of the TiN doping amount on the coating performance was systematically investigated. The results show that when the doping amount is 0 g/L, the coating thickness is about 33 μm ± 10%, the surface is smooth, with low roughness, and the interface between the coating and the substrate is straight. When the doping amount is 0.2 g/L, the microstructure of the coating is optimal, the surface maintains excellent smoothness, the bonding interface appears irregular and wave-like, there are no obvious cracks inside, and the mass percentage of O is 25.6%. When the doping amount is 0.5 g/L, the coating cannot form a complete continuous structure, and only local discrete oxidation products are present. When the doping amount is 1 g/L, the surface smoothness of the coating significantly decreases, and there are noticeable thickness differences. A uniform and continuous coating was formed on the surface at a concentration of 0.2 g/L. The pore sizes were moderate and evenly distributed, and the melting morphology at the pore edges was regular and complete. When 0 g/L of dopant is added, the titanium matrix undergoes gradual oxidation to form a TiO2, Ti2O3, and Ti phase system. After doping with TiN, TiN is found in the coating, which promotes the formation of TiO2. This study provides theoretical guidance and technical support for regulating the structure-performance relationship and improving key properties such as mechanics and corrosion resistance of titanium alloy MAO coatings.

This paper proposes a reproducible image encryption algorithm utilizing two two-dimensional chaotic maps, denoted by System I and System II. In response to the need for a more complete dynamical and cryptographic validation, the revised study extends the original Lyapunov-exponent, phase-portrait, and bifurcation analyses by adding equilibrium-point equations, piecewise Jacobian matrices, local stability criteria, and a basin-of-attraction investigation protocol. The maps are embedded in a plaintext-related confusion–diffusion architecture in which SHA-256 is used to derive the initial conditions and control parameters through explicit conversion equations. Security is evaluated using histogram uniformity, correlation coefficients, key sensitivity, differential metrics, bit-level and pixel-level avalanche tests, Shannon entropy, approximate entropy, sample entropy, and NIST SP 800-22 randomness testing. The manuscript also clarifies the practical meaning of key-space estimation under finite-precision arithmetic, provides a formal discussion of chosen-plaintext resistance, and reports the experimental conditions required for fair computational comparison. Robustness against noise and occlusion is quantified through PSNR, SSIM, BER, and recovery accuracy. The comparative discussion has been revised to avoid unsupported superiority claims and to present the proposed method as competitive with recent chaos-, cellular-automata-, ECC-, and hybrid-based image encryption schemes.

This work presents the competing roles of nonreciprocal advection and elastic stiffness in governing topological soliton dynamics within a one-dimensional rotator chain. The lattice model incorporates three independently tunable mechanical couplings: nearest-neighbor stiffness, fixed-span nonlocal stiffness, and a spatially uniform antisymmetric (nonreciprocal) coupling that introduces nonconservative directional forcing. A continuum reduction is performed to extract the dominant advective and elastic contributions, yielding scaling relations for propagation speed and intrinsic soliton width. Numerical experiments, benchmarked against a baseline configuration, demonstrate a continuous transition from coherent translation, through radiation-dominated propagation, to localized oscillatory trapping as the effective elastic length scale increases relative to advective strength. The antisymmetric coupling provides linear control of drift velocity, consistent with an overdamped scaling analysis. The two elastic couplings collectively determine an effective stiffness that sets the soliton width; larger widths enhance spectral overlap with linear lattice modes, promoting radiative losses. These findings establish a parameter-phase diagram that delineates regimes suitable for three operational modalities: high-fidelity directional transport, programmable radiation, and local energy trapping. This work offers a systematic framework for designing programmable wave-control devices in nonreciprocal mechanical metamaterials.

This paper proposes a method for real-time synthesis of reconfigurable pulses. The approach employs a high-voltage ultra-wideband (UWB) pulse source as the foundation, utilizing a genetic algorithm (GA) to optimize pulse synthesis parameters for targeted waveform generation. The method achieves not only peak power synthesis but also enables real-time arbitrary waveform synthesis through precise configuration of time delays and switching states of elementary pulses, thereby facilitating flexible switching between operational modes to meet diverse application scenarios. To address the insufficiency of the Pearson correlation coefficient in achieving high-fidelity waveform matching, a multi-objective fitness function is formulated for the GA, enhancing waveform consistency between synthesized and target pulses. Simulation results indicate that the waveform consistency between synthesized and target pulses exceeds 90% for positive Gaussian, negative Gaussian, and bipolar pulses, and surpasses 80% for double-exponential pulses. Experimental validation using a high-voltage UWB pulse source demonstrates that all synthesized positive Gaussian, negative Gaussian, and bipolar pulses achieve waveform consistency above 85% with targets, while double-exponential pulses exceed 75%, verifying the effectiveness of the proposed methodology.

This paper adopts a coupled fluid–structure interaction method based on computational fluid dynamics and the finite element method to investigate the high-speed vertical water entry of hollow truncated cone shells and systematically reveal the regulatory mechanism of the sidewall inclination angle on their hydrodynamic and structural response characteristics. The results show that hollow truncated cone shells exhibit a unique jet–cavity coupling effect, characterized by an upward jet penetrating the shell from the bottom and an axisymmetric cavity. Shells with an acute sidewall inclination angle have the lowest velocity and displacement, which further decrease as the inclination angle decreases, while the jet height and cavity diameter increase. In contrast, shells with an obtuse sidewall inclination angle show the highest velocity and displacement, but their velocity attenuation accelerates and the jet height decreases significantly with an increasing inclination angle. In addition, the fluid force and stress of hollow truncated cone shells follow a distribution pattern of high at the bottom and low at the top, and both the peak fluid force and peak stress exhibit a monotonically decreasing trend with increasing sidewall inclination angle.

The weak interlayer bonding in van der Waals heterostructures offers opportunities to tune their properties not only through deliberate composition changes, but also by altering the registry between layers. In this work, we systematically study the effects of finite twist angles on transition-metal dichalcogenide bilayers of MoSe2/WSe2 using first-principles calculations. The twisting of these bilayers breaks local symmetry and thus alters their electronic band structures. We suggest that the effects of twisting may be experimentally observed in Hall and scanning tunneling microscopy experiments and that the twist in these bilayers can be used as an effective mechanism to control charge carriers in future electronic devices.

For red micro-light-emitting diode (micro-LED) structures, InGaN or AlGaInP is typically used as the active material, and these materials exhibit markedly different size-dependent external quantum efficiency (EQE) behaviors. While previous analyses of InGaN and AlGaInP micro-LEDs have mainly focused on internal quantum efficiency, the influence of light extraction efficiency (LEE) on size-dependent EQE has been relatively unexplored. In this study, we numerically investigated the LEE characteristics of InGaN and AlGaInP micro-LED structures using finite-difference time-domain simulations. We compared the LEE characteristics of InGaN and AlGaInP micro-LEDs by systematically varying structural parameters, such as the distance from the quantum well to the Ag reflector, the side length, and the height of the micro-LED structures. In planar geometry, the LEE of InGaN LEDs can be up to twice that of AlGaInP LEDs due to their large refractive index contrast. However, in micro-LED structures, the LEE ratio of InGaN to AlGaInP was found to decrease significantly as the side length decreased, especially in the epoxy-encapsulated structure. For a side length of 2 μm with epoxy encapsulation, the total-emission LEE of InGaN micro-LEDs was only about 20% higher than that of AlGaInP micro-LEDs. The substantial size-dependent LEE variations between InGaN and AlGaInP micro-LEDs highlight the importance of considering LEE differences when comparing the EQE characteristics of red micro-LEDs based on these materials.

The space potentials of microwave electron cyclotron resonance (MW-ECR) plasmas with different discharge powers are diagnosed using an emissive probe made of molybdenum. The simulation of the molybdenum filament temperature at different heating currents reveals that the molybdenum emissive probe can reach ∼2000 K when generating appreciable electron emission, which is about 300 K lower than that of a tungsten emissive probe (∼2300 K), demonstrating the advantage of the molybdenum emissive probe in operating at a lower temperature. In addition, the contrast diagnosis results of MW-ECR plasmas using the molybdenum emissive probe with different diagnostic methods show that the plasma potentials determined by the improved inflection point method and the hot probe with zero emission limit method are in close agreement. In contrast, the plasma potentials obtained by the floating point method are consistently underestimated with a relative difference of about 3%.

The investigation of mechanisms for the controlled excitation and modulation of localized optical field structures remains a pivotal theme in nonlinear optics. This study synergizes similarity transformations with the Darboux transformation to derive exact analytical solutions for dispersion-decaying fiber systems. Leveraging these solutions, the dynamic evolution of multi-configurational rogue wave signals within such fibers is systematically elucidated, unveiling the intricate processes underlying nonlinear localized waveform transformations. It is demonstrated that by tailoring the topological configuration of the initial rogue wave, a diverse array of soliton pulses can be deftly excited, encompassing W-shaped solitons, double-peaked solitons, double W-shaped solitons, paired dark-anti-dark solitons, triple W-shaped solitons, and triple-peaked solitons. This novel approach, predicated upon the rogue wave evolution trajectory, transcends the conventional constraints of parameter modulation, thereby offering an innovative paradigm for optical soliton manipulation. The resultant heterogeneous soliton architectures exhibit considerable promise for optical information transmission: dark solitons, with their robust interference resistance, are ideal for high-fidelity optical communication systems; multi-peak solitons’ temporal modulation capabilities facilitate the construction of all-optical logic switches; meanwhile, composite modes of distinct soliton morphologies provide pioneering optical sources for biomedical multimodal imaging. This work not only broadens the theoretical landscape of nonlinear localized wave phenomena but also lays a foundational framework for the advancement of novel photonic devices.

MWCNT-coated yarn-based force sensors were effectively produced through a straightforward dipping-and-drying technique. The incorporation of a parallel capacitor enabled an impedance-based sensing approach that leverages variations in the area of Cole–Cole plots. This yielded a sensitivity of ∼0.8 kPa−1—substantially outperforming the sensitivity of roughly 0.49 kPa−1 of conventional resistance measurements—owing to the quadratic dependence of the visualized area variation of impedance data on the resistance ratio. Finally, a real-time impedance data detection system, utilizing an Arduino micro-controller and deep learning method, was demonstrated for a wide range of applications, such as wearable and healthcare devices.

High Resolution Image Download MS PowerPoint Slide Tin and germanium carbonates, Sn[CO 3 ] 2 and Ge[CO 3 ] 2, were synthesized by the reaction of SnO 2 or GeO 2 with CO 2 at high pressures and high temperatures in a laser-heated diamond anvil cell. Their structures were solved by in situ single-crystal X-ray diffraction at high pressures. Sn[CO 3 ] 2 formed at ∼30 GPa, while Ge[CO 3 ] 2 formed at around 44 GPa. Both carbonates are isostructural and crystallize in the trigonal space group P 3. The distinguishing feature of the Sn[CO 3 ] 2 or Ge[CO 3 ] 2 structures is the presence of isolated [CO 3 ] 2– groups, which are arranged in layers. Both structures contain octahedrally coordinated tetravalent Sn 4+ and Ge 4+ cations in two positions with partial site occupation. Bulk moduli of both carbonates are K 0 ≈ 44–48 GPa. Full geometry optimizations based on DFT calculations reproduced the crystal structures. The DFT models were used to complement the experimental compression data and for the assignment of Raman modes. Both Sn and Ge carbonates can be recovered under ambient conditions after pressure release.

The synthesis of zeolitic imidazolate framework-8 (ZIF-8) nanoparticles was investigated using in situ ultrasound monitoring. Particle formation was tracked by measuring ultrasound attenuation and velocity via the pulse-echo method. This noninvasive technique enables the observation of molecular sieve syntheses in both solid and liquid phases with high time-resolution without interfering with the process. The method offers novel insights into the formation mechanism of ZIF-8, including the identification of a crystalline intermediate phase, ZIF-L, prior to the formation of ZIF-8. We show that the ultrasound attenuation is sensitive to the nanoparticle size and can be, thus, used for determination of the particle size in future applications.

The crystallization behavior of 2,4,6-trinitrotoluene (TNT) confined within a hierarchical macro-microporous ZIF-8 (SOM-ZIF-8) framework and its impact on thermal decomposition are systematically investigated. TNT is incorporated into the porous host via evaporative crystallization, resulting in composites with varying TNT loadings. The well-defined macropores serve as templates for the confined growth of TNT nanospheres, while the intrinsic micropores are expected to facilitate the adsorption of key decomposition intermediates, potentially promoting autocatalytic decomposition pathways. XPS analysis reveals a negative shift of Zn 2p peaks and a positive shift of the –NO 2 N 1s peak, indicating electron transfer from the nitro groups to the Zn 2+ centers─an interfacial interaction further supported by the blue shift of –NO 2 vibrations in FTIR. This confined crystallization dramatically alters the thermal decomposition behavior: the peak decomposition temperature decreases from 320 °C for pristine TNT to as low as 180 °C for the composite, and the apparent activation energy is reduced from 131.6 kJ·mol –1 to 75.1 kJ·mol –1 . Combustion tests reveal significantly enhanced flame intensity and a maximum temperature increase from 889.5 to 1216.0 °C. The optimal loading (TNT: SOM-ZIF-8 = 5:1 by mass) achieves a balance between microporous catalysis and macroporous nanoconfinement, leading to the most efficient energy release. This work demonstrates that confined crystallization within hierarchically porous MOFs is an effective crystal-engineering strategy to tailor the thermal decomposition kinetics of conventional explosives, offering new insights into structure–property relationships in energetic materials.

Developing earth-abundant catalysts for low-temperature carbon monoxide (CO) oxidation is important for next-generation emission control, particularly in industrial scenarios where precious-metal catalysts face cost and stability constraints. Here, we report an “inverse” catalyst architecture in which LaMn 0.6 Cu 0.4 O 3 (LMCO) perovskite is integrated with CuO x -derived phases to form 80Cu-LMCO. The catalyst reaches a T 90 of 60 °C for CO oxidation, outperforming conventional perovskite and copper oxide catalysts under comparable conditions. Unlike previously reported CuO x or perovskite catalysts, this system uses an inverse CuO x /perovskite architecture to spatially separate O 2 activation from CO adsorption while coupling these processes through interfacial active-oxygen transport. In situ spectroscopy, 18 O 2 isotopic-exchange experiments, and density functional theory (DFT) calculations further support this pathway by showing that LMCO activates oxygen and provides labile oxygen species, whereas reduced Cu-containing phases provide CO adsorption sites and mediate oxygen transfer toward interfacial Cu + species. This active-oxygen transport pathway provides a mechanistic basis for designing robust, low-cost catalysts for low-temperature oxidation reactions.

Aluminum hydride (AlH 3 ) is a promising high-energy-density fuel for solid propellants, yet its sensitivity to moisture severely limits practical applications. Herein, an inorganic–organic dual-shell surface architecture is constructed to enhance the water resistance of AlH 3, comprising an atomic-layer-deposited TiO 2 inorganic inner layer and a perfluorodecyltrimethoxysilane (FAS-17) outer layer. The conformal TiO 2 interlayer (2.5 nm) acts as a robust barrier to hinder permeation and improve the thermal stability of AlH 3, while subsequent FAS-17 modification (4.6 nm) yields a superhydrophobic surface via stable interfacial Si–O–Ti bonds. As a result, the coated AlH 3 maintains an exceptional mass retention of 99.95% after exposure at 25 °C and 85% relative humidity for 15 days. Hydrothermal and acidic aging tests conducted in liquid environments at 50 °C further reveal substantially suppressed hydrogen release and better-preserved particle morphology for the coated AlH 3 . These improvements are attributed to the dual-shell nanocoating, which enhances mechanical integrity and effectively blocks water penetration. This work highlights the effectiveness of atomic-layer-deposited interlayers combined with hydrophobic surface modification for stabilizing moisture-sensitive energetic materials.

Developing sustainable high-performance composites is crucial for achieving circularity in advanced structural materials. Herein, we report a fully bio-based strategy for constructing recyclable carbon fiber-reinforced composites (CFRCs) based on dynamic non-isocyanate polyurethane (NIPU) matrices. Three cardanol-derived amine curing agents with tunable functionalities were rationally designed and synthesized from renewable cardanol, and subsequently reacted with lignin-derived cyclic carbonates (LCCs) to form a robust yet reprocessable NIPU network. Structure-property analyses reveal that the molecular architecture of the cardanol-derived curing agents governs the balance between network rigidity and flexibility, thereby tailoring the thermomechanical performance of the NIPUs. Optimizing carbonate structures and amine functionality yields polymers that combine high mechanical strength (tensile strength: 44.5 MPa) with excellent thermal and solvent resistance. The presence of hydroxyurethane linkages confers dynamic covalent character via reversible transcarbamoylation, imparting efficient reprocessability and pronounced multiple-shape-memory effects. Notably, the reprocessed NIPU retains >75% of its initial tensile strength after three hot-pressing cycles. As CFRC matrices, the optimized NIPU ensures outstanding interfacial adhesion and closed-loop recyclability, allowing solvent-assisted deconstruction to recover carbon fibers with nearly preserved mechanical integrity. This research establishes an eco-friendly and scalable approach to producing entirely renewable, recyclable and superior-performance composite materials for sustainable engineering applications.

Numerous interfacial materials have been explored for efficient perovskite solar cells (PSCs). The identification of optimal candidates from the vast chemical space remains a difficult and costly task. Artificial intelligence (AI)-assisted materials screening has emerged as a convenient route to benefit and promote the pace of PSC research. Here, we propose a two-step cascade screening strategy that integrates a contrastive learning-based graph neural network (CLGNN) with a gradient boosting decision tree regressor (GBDTR) to balance high-throughput and predictive accuracy. Among them, CLGNN is a graph contrastive learning model trained on large-scale unlabeled molecular graph topologies, whereas GBDTR is a supervised regression model trained on a manually curated and labeled database. Using CLGNN, we screened one million molecules on a graphics processing unit (GPU) and shortlisted 128 candidates within 10 min. This step substantially reduced the number of molecules requiring subsequent density functional theory (DFT) calculations and experimental validation. We then developed and evaluated multiple regression models based on multidimensional physicochemical descriptors to accurately predict device performance. Two effective buried-interface modifiers, 4,4′-iminodibenzoic acid (4,4′-IDA) and 4,4′-biphenyldicarboxylic acid (4,4′-BA), were selected, which delivered a high-power conversion efficiency of 26.10% with an open-circuit voltage ( V OC ) of 1.184 V and a fill factor (FF) of 86.05% using antisolvent-free processing. This work exemplifies an efficient route for scalable and rapid exploration of new materials for PSCs.

Interfacial instability and sluggish kinetics of high-purity aluminum (Al) anodes remain major bottlenecks for rechargeable nonaqueous aluminum-ion batteries (AIBs) to achieve high electrochemical performance. This study systematically evaluates the effects of alloying compositions on dendrite formation in commercial AA1235, AA3003, and AA8006 Al alloys as scalable, high-performance and low-cost anodes in chloroaluminate-based electrolyte AIBs. Comprehensive results demonstrate that the commercial Al alloys achieve superior cycling stability over pure Al metal benefited by leveraging a balanced intermetallic distribution that promotes uniform Al plating and suppresses vertical dendrite propagation. In contrast, high-purity Al exhibits limited long-life cycles due to its inhomogeneous native oxides. Our findings reveal that tailored commercial alloys can outperform their high-purity materials, offering a strategic pathway for durable and cost-effective energy storage based on multivalent metal-ion chemistries.

Halide perovskites exhibit exceptional optoelectronic properties, including strong light absorption and efficient generation of photogenerated charge carriers. However, these advantages are extremely limited in electrocatalytic systems, and their full potential remains largely unexplored. In particular, the underlying mechanisms governing light-assisted electrocatalysis in perovskite materials remain poorly understood. Herein, a Pt-modified Cs 2 PdBr 6 all-inorganic halide perovskite (Cs 2 PdBr 6 @Pt 1.5 ) is designed, which achieves a low overpotential of 11 mV at 10 mA cm –2 with excellent water stability. Femtosecond transient absorption spectroscopy further demonstrates that the incorporation of Pt increases the population of transient species (<1 ps) and acts as an efficient charge separation channel, thereby promoting charge migration to catalytic active sites and enhancing hydrogen evolution reaction properties. Density functional theory (DFT) calculations reveal that electrons transfer from Cs 2 PdBr 6 to Pt, and Pt-modified Cs 2 PdBr 6 optimizes the adsorption energies of key reaction intermediates, thereby lowering the overpotential for water splitting. These findings highlight the potential of halide perovskites as a stable and efficient platform for light-assisted electrocatalytic water splitting and related energy conversion processes.