The effects of quench sensitivity on the mechanical properties and corrosion resistance of AA7046 aluminum alloy were investigated using hardness and tensile tests, immersion corrosion, and intergranular corrosion (IGC) tests, combined with scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), electron backscatter diffraction (EBSD), high-resolution transmission electron microscopy (HRTEM), and scanning Kelvin probe force microscopy (SKPFM). As the quench rate decreased from 422.7 to 4.7 ℃/s, the tensile strength (TS) and yield strength (YS) decreased by 13.6 and 14.1

ABSTRACT Two‐dimensional (2D) heterostructures have significant application promise in electronics, optoelectronics, and integrated circuits due to their unique structural designs, high‐density integration, and transformative physical properties. To establish 2D heterostructures as essential components for next‐generation integrated devices, it is crucial to develop approaches for the integration of heterostructure units with varying physical properties. Herein, we demonstrate an atomic substitution method for preparing composition‐ and bandgap‐tunable patterned lateral Janus heterostructure arrays. Patterned WS 2 ‐WSe 2 lateral heterostructure arrays were synthesized through a laser‐assisted epitaxial regrowth process. Then, using a hydrogen plasma‐assisted sulfur substitution method at room temperature, the top layer atoms of WSe 2 were sulfurized to different degrees to Janus W(S x Se 1‐x )Se (0 ≤ x ≤ 1), successfully fabricating WS 2 ‐Janus W(S x Se 1‐x )Se lateral heterostructure arrays. Notably, the composition and bandgap of W(S x Se 1‐x )Se are tunable with the S content, which is proved by density functional theory calculations, X‐ray photoelectron spectroscopy, Raman, and photoluminescence spectra. Comprehensive characterizations prove that the lateral heterostructures remain an atomically clean and sharp interface. The successful introduction of bandgap‐tunable Janus structures into monolayer lateral heterostructure arrays provides unprecedented flexibility for constructing 2D lateral heterostructures, which is important for the development of complex 2D lateral devices and integrated circuits.

To overcome the low interfacial strength of 7xxx aluminum alloy/steel joints resulting from poor material flow, this study proposes a low-transverse-speed friction stir additive manufacturing (FSAM) method to fabricate highstrength 7075/316L joint interfaces by enhancing material fluidity. Finite element method (FEM) was used to simulate the plastic flow behavior of the material, verifying that sufficient material flow at the joint interfaces can be achieved under the FSAM process parameters. The interface morphology, grain structure and phase composition were characterized by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), energy dispersive spectroscopy (EDS), and high-resolution transmission electron microscopy (HRTEM), and the shear properties were tested for the joint interfaces. The results showed that an amorphous layer approximately 100 nm thick is formed, and Fe4Al13 and Fe2Al5 intermetallic compounds (IMCs) with sizes of 50-60 nm are dispersed within the amorphous layer. The average shear strength was 122 +/- 3 MPa, and it is 21.1% higher than the maximum strength of the previously reported FSAM Al/steel joint interfaces. Based on the Al-Fe binary phase diagram within the temperature range of FSAM, the evolution sequence of IMCs within the joint interfaces is inferred to analyze the formation mechanisms of Fe4Al13 and Fe2Al5 in the amorphous layer, and the formation mechanism of amorphous layer containing IMC particles is discussed for 7075/316L joint interfaces. Molecular dynamics (MD) simulations further confirmed that the amorphous interface containing Al-Fe IMCs particles has a higher shear strength than the amorphous interface without particles. The proposed method can effectively improve the interface strength of dissimilar metal connections between aluminum and steel, and it is of engineering applicability for the additive manufacturing of high-strength Al/steel composites.

Aluminum-titanium composite materials are widely used in the aerospace field due to their high specific strength and excellent corrosion resistance. Al-Cu-Li alloys, known for their high specific strength and stiffness, are considered an ideal choice for preparing lightweight and high-strength aluminum-titanium composites. However, the relatively low melting point, low density, and high thermal conductivity of Al-Cu-Li alloys lead to significant differences in physical and chemical properties between Al-Cu-Li alloys and Ti alloys. Therefore, the processability of Al-Cu-Li and TC4 alloys via friction stir additive manufacturing (FSAM) is more challenging compared to conventional Al alloys. In this work, the lightweight and high-strength AA2195 aluminum alloy and TC4 titanium alloy for aerospace were selected. The AA2195/TC4 composites were prepared by FSAM. Combined with DFT calculation, the corrosion mechanism of the AA2195/TC4 joint interfaces was deeply revealed. The corrosion resistance and corrosion behavior of the joint interfaces of AA2195/TC4 composites prepared by FSAM in 3.5 wt.% NaCl solution were investigated through electrochemical tests and quasi-in-situ immersion corrosion tests. The results show that the corrosion current density of the prepared AA2195/TC4 composites is 1.49 x 10-8 A/cm2, and it has electrochemical corrosion resistance between AA2195 aluminum alloy (1.20 x10-7 A/cm2) and TC4 titanium alloy (9.37 x10-9 A/cm2). During the corrosion process, initially only slight pitting occurred on one side of AA2195 aluminum alloy. As corrosion duration increased, the alloy near the interfaces transitioned from pitting to severe intergranular corrosion. Meanwhile, the Scanning Kelvin probe force microscopy (SKPFM) results show that the AA2195 aluminum alloy near the joint interfaces has the largest surface potential difference with Al-Ti intermetallic compounds (IMCs), with a value of 142.98 mV, and thus the corrosion phenomenon is the most severe. Furthermore, the surface work functions of Al(111), Ti(001), TiAl2(001), and TiAl3(100) were calculated respectively through density functional theory (DFT) calculations. The results show that Al(111) has the smallest surface work function, explaining its propensity for preferential corrosion. This work fundamentally reveals the corrosion mechanism of the Al/Ti composites joint interfaces prepared by FSAM and provides a scientific basis for the preparation of AA2195/TC4 composites for aerospace.

Layered Bi2Se3 has been designed as a promising anode material for aqueous batteries due to its large interlayer spacing and high specific capacity. However, Bi2Se3 is a topological insulator, its interior presents an insulating state, which results in a slow reaction dynamics. Moreover, it is found that unmodified Bi2Se3 has a poor structural stability during charging/discharging. Hence, we design conductive polypyrrole coated hollow Bi2Se3 particles (Bi2Se3@PPy) to solve these problems. Various experiments show that the PPy possesses bifunctional features and enhance the electrical conductivity and structural stability of Bi2Se3. The hollow structure of Bi2Se3 exposes abundant active sites and shortens the diffusion paths of Mg2+. As a result, at current density of 0.2 A g-1, Bi2Se3@PPy offers high discharge capacity of 134 mA h g-1 in aqueous magnesium ion battery. More importantly, Bi2Se3@PPy//Mn3O4 full cell presents discharge capacity of 66 mA h g-1 at 0.5 A g-1. Furthermore, Bi2Se3@PPy exhibits good electrochemical performance in ammonium ion battery. This paper provides a feasible strategy to enhance the structural stability and ionic/electronic conductivity of topological insulator.

Under intense optical illumination, piezoelectric semiconductors (PSs) undergo non-uniform temperature rise due to radiative heat transfer, which generates polarized charges and modifies the device barrier structures. This study develops a nonlinear multiphysics coupling model for piezoelectric semiconductor double-barrier structures (PS-DBSs), incorporating energy conversion processes under opto-thermoelectric coupled loading. Results show that the base current in PS-DBSs is primarily governed by the equivalent photoelectromotive force (E-PEMF) induced by optical loads, while the collector current is mainly controlled by the equivalent thermoelectromotive force (E-TEMF) from thermal loads. This finding reveals that quantitative decoupling of opto-thermal coupled excitation can be achieved via dual-electrode signals, a mechanism that remains valid over a wide operating voltage range. Further analysis indicates that the underlying mechanism originates from the competitive interplay between E-PEMF and E-TEMF in modulating carrier transport, suggesting that rational structural design enables PS devices to self-regulate under external excitation. Overall, this work provides new insights for developing space-borne optoelectronic sensors and high-performance solar cells.

Herein, we report the rational balancing of hydrogen adsorption/desorption dynamics by employing a synergistic Co and V dual-doping strategy to enhance the hydrogen evolution reaction (HER) performance of MoS2. The Co and V dual-doping MoS2 (Co, V-MoS2) was successfully synthesized in situ on carbon cloth (CC) substrates via one-pot hydrothermal route, and the XRD, Raman, TEM, XPS, EDS and ICP characterizations validate the substitutional doping of Co and V into the MoS2 lattice. The optimized Co, V-MoS2/CC exhibits significantly enhanced HER performance, requiring only 220.0 mV overpotential to reach-100 mA/cm2 with a 61.9 mV/dec Tafel slope, surpassing both the Co/V mono-doped MoS2/CC and undoped MoS2/CC. Moreover, the polarization curve of Co, V-MoS2/CC exhibits a negligible potential decay of 8.4 mV at 50 mA/cm2 after 3000 repeated cyclic voltammogram cycles, demonstrating superior durability. DFT calculations reveal that synergistic Co and V dual doping in MoS2 can balance the hydrogen adsorption/desorption kinetics at S sites near dopants, thereby optimizing the hydrogen adsorption free energy and accelerating the charge transfer, thus achieving far super HER performance. Our balancing hydrogen adsorption/desorption strategy enabled by Co, V dual-doping provides a promising avenue for improving the HER performance of TMDs-based electrocatalysts.

P2-type layered Na0.7MnO2 is regarded as a promising cathode material for sodium-ion batteries due to its high specific capacity. However, Mn3+-induced Jahn-Teller distortion and Mn2+ dissolution result in the structural instability of Na0.7MnO2, thereby restricting its large-scale application. In this study, a K0.5MnO2@Na0.7MnO2 composite is prepared by a molten salt method and used as a cathode. In particular, partial K+ in K0.5MnO2 substitutes for the Na+ sites in Na0.7MnO2 during the charge-discharge process, which decreases the Mn3+/Mn4+ ratio and provides wide Na+ channels, achieving fast reaction kinetics and long-term cycling stability. The persistent K0.5MnO2 throughout the entire testing process works as a robust K+ supply source and compensates for the K+ loss of K-doped Na0.7MnO2 during cyclic tests. Consequently, the cathode shows a high discharge capacity of 148 mA h g−1 at 0.04 A g−1 and outstanding cycling stability, with a capacity retention of 69% after 800 cycles at 0.5 A g−1. This research provides important references for designing high-performance layered cathode materials in sodium-ion batteries.

Two-dimensional MoS2 shows great promise for damage-resistant and adaptive functional devices owing to its intrinsic self-healing capability; however, phase-dependent damage and healing mechanisms remain unclear. Here, molecular dynamics simulations investigate the nano-indentation induced damage evolution and self-healing behavior of multilayer MoS2 with three phase structures (1T, 2H, and 3R). Load-depth response, interlayer sliding, displacement fields, crack propagation, maximum shear strain, and radial distribution functions reveal the underlying mechanisms. Results show that no cracks occur in the 1T phase, indicating excellent structural integrity. The 2H phase exhibits single-layer fracture or localized cracking, and no crack healing is observed in any of these cases. The 3R phase is prone to long strip-like cracks, most of which undergo partial healing. During healing, interlayer reconstruction induces edge dislocations and pronounced interlayer sliding, highly sensitive to the indenter radius. This study clarifies the phase-dependent damage and self-healing mechanisms of MoS2 at the atomic scale.

Traditional optical fiber communication encryption methods lack sufficient dynamic adaptability and hardware flexibility, while reconfigurable logic gates can overcome this limitation, thereby significantly improving the flexibility of encryption systems. This study reports a reconfigurable optoelectronic logic gate (OELG) system based on hafnium-zirconium oxide (HZO) ferroelectric thin films. Through ultra-low temperature atomic layer deposition technique, the fabricated HZO thin films demonstrate an exceptional pyroelectric coefficient (1835.91 µC m−2 K−1) and robust multi-level polarization stability, enabling efficient broadband photon-to-current conversion. By leveraging the pyroelectric effect and tunable polarization states, the OELG device achieves dynamic optical signal modulation and logic processing. The OELG device supports five fundamental logic operations (AND, OR, NAND, NOR, NOT) via electrical bias and polarization control, without requiring hardware modifications. The OELG device demonstrates stable performance over 109 cycles with no degradation, meeting practical application requirements. Furthermore, a convolutional neural network (CNN)-integrated image encryption-decryption framework was validated, achieving 95.01

Two-dimensional (2D) heterostructures have significant application promise in electronics, optoelectronics, and integrated circuits due to their unique structural designs, high-density integration, and transformative physical properties. To establish 2D heterostructures as essential components for next-generation integrated devices, it is crucial to develop approaches for the integration of heterostructure units with varying physical properties. Herein, we demonstrate an atomic substitution method for preparing composition- and bandgap-tunable patterned lateral Janus heterostructure arrays. Patterned WS2-WSe2 lateral heterostructure arrays were synthesized through a laser-assisted epitaxial regrowth process. Then, using a hydrogen plasma-assisted sulfur substitution method at room temperature, the top layer atoms of WSe2 were sulfurized to different degrees to Janus W(SxSe1-x)Se (0 ≤ x ≤ 1), successfully fabricating WS2-Janus W(SxSe1-x)Se lateral heterostructure arrays. Notably, the composition and bandgap of W(SxSe1-x)Se are tunable with the S content, which is proved by density functional theory calculations, X-ray photoelectron spectroscopy, Raman, and photoluminescence spectra. Comprehensive characterizations prove that the lateral heterostructures remain an atomically clean and sharp interface. The successful introduction of bandgap-tunable Janus structures into monolayer lateral heterostructure arrays provides unprecedented flexibility for constructing 2D lateral heterostructures, which is important for the development of complex 2D lateral devices and integrated circuits.

The microstructure, mechanical properties, and corrosion resistance of friction stir additive manufacturing (FSAM)-produced AA7075/316L composites were investigated via multi-scale characterization, mechanical testing, and electrochemical analysis. The results reveal the formation of an amorphous layer with a thickness of about 100 nm at the interface, accompanied by a small number of intermetallic compounds (IMCs) near the Al side of the amorphous layer. Dynamic recrystallization and recovery phenomena were observed in the AA7075 aluminum alloy under mechanical stirring, leading to significant grain refinement with an average size of 3.3 ± 1.1 μm. Tensile strength and yield strength of composites were 413 MPa and 227 MPa, respectively, with an elongation of 10.9

Resolution is one of the key indicators in the cavity optomechanical mass sensing. The bound states in the continuum (BIC) enable extremely narrow linewidths, which have great potential for enhancing the resolution of cavity optomechanical mass sensors. In order to enhance the resolution of cavity optomechanical mass sensing, we propose a simple double-cavity optomechanical system under the blue-detuning condition to realize the BIC singularity, and present an ultrahigh-resolution mass sensing scheme based on BIC in this paper. By solving the linearized Heisenberg-Langevin equations, the expressions for the susceptibility and transmission rate of the system are derived. Based on the system's susceptibility, we study the absorption characteristics of the probe field under the blue-detuning condition. The absorption spectrum of the system exhibits three peaks, among which the central narrow peak exhibits optical gain characteristics, collectively forming a phenomenon analogous to double optomechanically induced transparency. Then, analysis of the dressed-state energy-level structure reveals that the formation of the central narrow peak stems from quantum interference effects in a double-L-type dark-state resonance. The linewidth evolution of the quasi-BIC central narrow peak is investigated by analyzing the dependence of the real part and imaginary part of the corresponding eigenvalue on the optomechanical coupling strength. It can be found that the imaginary part of the eigenvalue for the central narrow peak becomes zero when the optomechanical cooperativity coefficient equals the double-cavity cooperativity coefficient plus one, enabling the realization of BIC. The linewidth of the central peak is ultrasmall under this BIC condition, and the shift of the transmission peak in the transmission spectrum is linearly related to the adsorbed mass. Based on these characteristics, the system under the BIC condition can achieve mass sensing with an ultrahigh resolution, with a resolution of approximately 1 ag. Meanwhile, the linewidth of the transmission peak can be suppressed below 1 Hz, which is superior to the traditional optomechanical mass sensing schemes based on four-wave mixing, photonic molecules, and plasmon polaritons. Systematic investigation of eigenvalue variations and the corresponding sensitivity enhancement factors under mechanical resonator frequency shift reveals that the real part and the imaginary part of the eigenvalue associated with the central peak exhibit negligible variations under such perturbations. This indicates that the mass sensing scheme based on BIC in the double-cavity optomechanical system can maintain ultrahigh resolution and precise mass measurement under mechanical resonator frequency shift. Our scheme provides an approach for realizing the BIC singularity in optomechanical systems, and presents a new route to improving the resolution of mass sensors based on cavity optomechanical systems.

It is found that Mo doping can enhance the supercapacitor performance of VS2 microflowers. The X-ray diffraction combined with energy dispersive X-ray, X-ray photoelectron spectroscopy, and Raman spectra results verify the successful doping of Mo atoms into the VS2 matrix. As the electrode material of supercapacitors, the Mo-doped VS2 performs better electrochemical performance than pristine VS2, achieving the specific capacitance of 170 F g−1 at 0.5 A g−1 and 389.5 F g−1 at 5 mV s−1. Furthermore, the symmetric supercapacitor based on the Mo-doped VS2 exhibits good stability and ideal rate capability. The enhanced capability is presumably ascribed to the more accessible active sites and faster electrons/ions diffusion kinetics, which are caused by the increased specific surface area, expanded interlayer spacing, and improved conductivity after Mo doping. This strategy can also be extended to strengthen the capacitive properties of other transition metal dichalcogenides for advanced energy storage devices.

Developing insertion-type anodes is essential for designing high-performance "rocking chair" zinc-ion batteries. BiOCl shows great potential as an insertion-type anode material for Zn2+ storage due to its high specific capacity and unique layered structure. However, the development of BiOCl has been significantly hampered by its poor stability and kinetics during cycling. In this study, Br-doped and carbon-coated BiOCl ultrathin nanosheets (Br-BiOCl@NC) are synthesized as high-performance anodes. The ultrathin nanosheet morphology facilitates Zn2+/H+ transfer and the Br doping reduces the Zn2+/H+ diffusion barrier. Additionally, the carbon coating enhances the electronic transfer. Furthermore, an insertion-conversion mechanism involving H+ and Zn2+ storage is revealed by ex-situ tests. Therefore, Br-BiOCl@NC exhibits a high discharge capacity of 174 mA h/g at 500 mA/g without capacity degradation after 1000 cycles. The Br-BiOCl@NC//MnO2 full cell presents a discharge capacity of ≈ 120 mA h/g at 200 mA/g. This work offers valuable insights for the design of high-performance insertion-type anode materials in zinc-ion batteries.

To address the detrimental effects of conventional positive pressure arc (PPA) welding—particularly its destabilizing repulsive forces on molten pool dynamics in thin-walled structural fabrication—this study proposes a groundbreaking pumping gas hollow tungsten negative pressure arc (PHT-NPA) welding or additive manufacturing (AM) method. Unlike traditional PPA, which generates destabilizing repulsive effects (RE), the novel PHT-NPA technique utilizes a longitudinal magnetic field (LMF)-controlled hollow tungsten arc (HTA) to create negative pressure arc forces with intrinsic adsorption effects (AE), thereby stabilizing the molten pool. The core innovation lies in the synergistic integration of three elements: (1) a custom-designed hollow tungsten electrode for gas flow modulation, (2) an LMF-based arc adjusting mechanism to reconfigure plasma dynamics, and (3) a multi-physics-coupled arc plasma model that systematically investigates temperature fields, velocity fields, arc force, and current density distributions under arc negative pressure conditions. Through this framework, we establish quantitative mappings between LMF parameters, electrode geometry, operational approaches, and the resultant negative pressure arc forces. Critical thresholds for generating stable adsorption-dominated NPA are identified, along with the effective range of AE-driven molten pool stabilization. Furthermore, this work elucidates the formation mechanism and arc design principles of PHT-NPA welding, offering a systematic methodology for arc parameter optimization. By replacing RE-prone PPA welding with AE-enhanced PHT-NPA welding, this research provides a transformative solution to molten pool instability challenges in precision arc welding or AM, paving the way for next-generation sustainable welding manufacturing technologies in aerospace, microelectronics, and other thin-walled component applications.

Alternating cusp-shaped magnetic field, which can be used to effectively control welding quality, can significantly enhance the regular molten-pool oscillation signal during tungsten inert gas (TIG) welding; however, the nonlinear arc voltage signal causes the accuracy of penetration-state recognition to be very low. A novel method of performing penetration-state recognition that utilizes magnetic field-assisted molten-pool oscillation based on adaptive variational mode decomposition (VMD) of the arc voltage and hybrid deep learning is proposed in this paper. A subtractive averaging-based optimizer (SABO)-VMD algorithm was selected to preprocess the arc voltage signals, in which the adaptive bandwidth optimization mechanism can dynamically adjust the parameters according to the signal characteristics to achieve the global optimal solution, thereby enhancing the quality of the signal decomposition. After the hyperparameters of the convolutional neural network (CNN) and support vector machine (SVM) were optimized by the rime optimization algorithm (RIME) and the grid search algorithm, respectively, the CNN-SVM classification algorithm was constructed by combining the powerful featureextraction capabilities of the CNN and the efficient classification performance of the SVM. The nonlinear components of the arc voltage signal were separated by the SABO-VMD algorithm to obtain multiple intrinsic mode functions (IMFs) with different frequencies and amplitudes; this was done so that the eigenvector of the moltenpool penetration state could be extracted from the IMF with the lowest envelope entropy. Then, the CNN-SVM classification algorithm was used to recognize the penetration-state. The results show that the proposed method is robust and that its recognition accuracy can reach 95 % for various welding speeds.

This report reveals that the hydrogen evolution activity of VS2 can be effectively strengthened by inducing the surface charge redistribution of VS2 via P non-metal doping. The XRD, TEM, GPA, EDS and XPS characterizations confirm that the P atoms are successfully doped into the VS2/CC matrix by substituting S atoms, resulting in lattice tensile strain and charge redistribution. The optimal P-doped VS2 on carbon cloth (P-VS2/CC) exhibits a low overpotential of 274 mV at - 50 mA cm-2 and a small Tafel slope of 65.4 mV dec-1, much lower than those of VS2/CC counterpart (622 mV and 120.1 mV dec-1, respectively). Moreover, the P-VS2/CC delivers a long-term stability for 55 h without decay at 10 mA cm- 2, outperforming the VS2/CC. Density functional theory calculations suggest that P doping can induce the charge transfer from S and V to nearby P atoms, resulting in the decrease of hydrogen adsorption free energy at the S and V sites and the increase of total density of states at the Fermi level, thus far super hydrogen evolution activity. This work provides a hopeful new route for strengthening the HER activity of VS2, and offers a new perspective for developing advanced transition-metal chalcogenides electrocatalysts.

We present a scheme for the electromagnetically-induced-absorption(EIA)-like ground state cooling in a hybrid optomechanical system which is combined by two-level quantum systems(qubits) and a high-Q optomechanical cavity. Under the weak qubit-cavity coupling, the system exhibits an EIA-like effect and this effect is caused by quantum destructive interference that is distinct from the conventional EIA effect driven by quantum constructive interference. More importantly,the EIA-like cooling mechanism can significantly enhance the cooling rate of the hybrid system, enabling the final phonon number beyond the classical cooling limit in the strong optomechanical coupling regime. Meanwhile, the cooling effects of the EIA case is better than that of the normalmode splitting case under the same optomechanical coupling strength and qubit dissipation rate.

Rotational energy harvesters have the capability to convert substantial rotational energy from the environment into electric energy, providing an innovative solution for addressing the energy supply challenges faced by sensor nodes in the Internet of Things. This paper presents the design and implementation of a bistable beam-based energy harvester for rotational motion. The proposed harvester incorporates the magnetic excitation bistability and mechanical modulation boundary to enhance output performance and operational bandwidth. Theoretical model based on distributed-parameter modelling is employed to analyze dynamics of beam in search for optimal magnet arrangement mode with high input energy. Variations in output performance with the rotating speed of rotor are numerically calculated and experimentally measured. The output signal from the harvester can be utilized for the measurement and analysis of the input rotational motion. Additionally, stability testing has been conducted to assess whether the proposed harvester can sustain stable output voltage over 300 min testing period. It was found that the harvester demonstrates its self-powered characteristics by powering light-emitting diodes and a temperature sensor. This study is systematic, from design to implementation, and can provide structural design guidelines for improving performance of energy harvesters.