摘要：
Anisotropic plasmonic metasurfaces have attracted broad research interest since they possess novel optical properties superior to natural materials and their tremendous design flexibility. However, the realization of multi-wavelength selective plasmonic metasurfaces that have emerged as promising candidates to uncover multichannel optical devices remains a challenge associated with weak modulation depths and narrow operation bandwidth. Herein, we propose and numerically demonstrate near-infrared multi-wavelength selective passive plasmonic switching (PPS) that encompasses high ON/OFF ratios and strong modulation depths via multiple Fano resonances (FRs) in anisotropic plasmonic metasurfaces. Specifically, the double FRs can be fulfilled and dedicated to establishing tailorable near-infrared dual-wavelength PPS. The multiple FRs mediated by in-plane mirror asymmetries cause the emergence of triple-wavelength PPS, whereas the multiple FRs governed by in-plane rotational asymmetries avail the implementation of the quasi-bound states in the continuum-endowed multi-wavelength PPS with the ability to unfold a tunable broad bandwidth. In addition, the strong polarization effects with in-plane anisotropic properties further validate the existence of the polarization-resolved multi-wavelength PPS. Our results provide an alternative approach to foster the achievement of multifunctional meta-devices in optical communication and information processing.
摘要：
A series of heterostructured materials with variable ratio of 316 powders in 18Ni300 powders were prepared by laser melting deposition (LMD). The microstructural evolution and its influence on tensile features were explored before/after aging treatment or solution-aging treatment. The results indicated that the fraction of g phase was increased gradually with increasing 316SS, and dislocation caused by the deformation could be migrated and annihilated within the region of g phase, second phase strengthening could contribute to excellent elongation for 18Ni300 maraging steel. The elongation of the AF4 sample was 235.2% higher than that of the AF0 sample when a 37.5% reduction in the ultimate tensile strength occurred. In addition, thermal stress could exist in the as-cladded sample, an appropriate heat treatment could release the thermal stress and precipitate nanoscale intermetallic compound. Their synergistic effect could contribute to overcoming the strength-elongation trade-off. A relatively ideal sample, a discontinuous g phase surrounded by a phase, which displayed high strength of 1678.4 MPa with high elongation of 10.9% after solution-aging treatment. Compared with laser cladded 18Ni300 maraging steel, a 41.7% increment in the elongation was obtained at the cost of 11.3% reduction in ultimate tensile strength. & COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC
通讯机构：
[Fang Yu; Haiqing Zhou] K;Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Key Laboratory for Matter Microstructure and Function of Hunan Province, Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha 410081, China
关键词：
seawater splitting;electrocatalyst;bifunctional water splitting;non-noble metal;porous material
摘要：
Given the abundant reserves of seawater and the scarcity of freshwater, real seawater electrolysis is a more economically appealing technology for hydrogen production relative to orthodox freshwater electrolysis. However, this technology is greatly precluded by the undesirable chlorine oxidation reaction and severe chloride corrosion at the anode, further restricting the catalytic efficiency of overall seawater splitting. Herein, a feasible strategy by engineering multifunctional collaborative catalytic interfaces is reported to develop porous metal nitride/phosphide heterostructure arrays anchoring on conductive Ni2P surfaces with affluent iron sites. Collaborative catalytic interfaces among iron phosphide, bimetallic nitride, and porous Ni2P supports play a positive role in improving water adsorption/dissociation and hydrogen adsorption behaviors of active Fe sites evidenced by theoretical calculations for hydrogen evolution reactions, and enhancing oxygenated species adsorption and nitrate-rich passivating layers resistant to chloride corrosion for oxygen evolution reaction, thus cooperatively propelling high-performance bifunctional seawater splitting. The resultant material Fe2P/Ni1.5Co1.5N/Ni2P performs excellently as a self-standing bifunctional catalyst for alkaline seawater splitting. It requires extremely low cell voltages of 1.624 and 1.742 V to afford current densities of 100 and 500 mA/cm2 in 1 M KOH seawater electrolytes, respectively, along with superior long-term stability, outperforming nearly all the ever-reported non-noble bifunctional electrocatalysts and benchmark Pt/IrO2 coupled electrodes for freshwater/seawater electrolysis. This work presents an effective strategy for greatly enhancing the catalytic efficiency of non-noble catalysts toward green hydrogen production from seawater electrolysis.
通讯机构：
[Jinghao Huang] S;School of Mechanical Engineering, University of South China, Hengyang, Hunan 421001, China<&wdkj&>Hunan Provincial Key Laboratory of Emergency Safety Technology and Equipment for Nuclear Facilities, University of South China, Hengyang, Hunan 421001, China
关键词：
Oxidation behavior;Cr-coated Zr-4 alloy;Multi -arc ion plating;Cr-Zr diffusion;Oxidation weight gain
摘要：
The oxidation behavior of Cr-coated Zr-4 alloy is studied in air environment at temperatures ranging from 10 0 0 degrees C to 120 0 degrees C and for oxidation times ranging from 1 h up to 4 h. The oxidation weight gain, sample appearance, surface and cross-sectional microstructure, Cr-Zr diffusion and phase at different oxidation times for the three temperatures were analyzed in detail. The results reveal that the oxidation weight gain is parabola with oxidation time, and the parabolic rate constant increases with the increase of oxidation temperature. At 10 0 0 degrees C and 1100 degrees C, the Cr coating can provide oxidation protection for the internal Zr-4 alloy after 4 h of oxidation. While at 1200 degrees C, Cr coating can only provide effective oxidation protection for the internal Zr-4 alloy for 1 h. At 10 0 0 degrees C and 1100 degrees C, the thickness of the Cr-Zr diffusion layer increases linearly with the oxidation time, while at 1200 degrees C, the thickness of the Cr-Zr diffusion layer increases linearly with the oxidation time after 1-3 h of oxidation, and after 4 h of oxidation, it suddenly increases sharply. And the XRD results imply that the preferred orientation of Cr 2 O 3 grains is related to the oxidation temperature.
期刊：
Progress in Organic Coatings,2023年183:107819 ISSN：0300-9440
通讯作者：
Li, ZY;Wang, XZ;Ying, L
作者机构：
[Li, ZY; Li, Zhenye; Kang, Xiaomin; Wang, Gaoyang; Zhang, Meng] Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.;[Wang, Xingzhu; Wang, XZ] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.;[Ying, Lei; Ying, L] South China Univ Technol, Inst Polymer Optoelect Mat & Devices, State Key Lab Luminescent Mat & Devices, Guangzhou 510640, Peoples R China.
通讯机构：
[Li, ZY ; Wang, XZ ] U;[Ying, L ] S;Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.;Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.;South China Univ Technol, Inst Polymer Optoelect Mat & Devices, State Key Lab Luminescent Mat & Devices, Guangzhou 510640, Peoples R China.
关键词：
Titanium dioxide;Hole transport layer;Polymer solar cells;Power conversion efficiency;Stability
摘要：
Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been widely served as the state-of-art hole transport layer (HTL) for high performance organic solar cells (OSCs) due to its easy solution processability, excellent hole extraction ability, and well compatibility with various active layers. However, PEDOT:PSS shows several drawbacks such as relatively moderate conductivity and optical transparency, acidity, and reactivity, which directly limits the improvement of device performance and leads to the deterioration of device stability. In this work, metal oxide titanium dioxide (TiO2) was doped into the conventional HTL-material PEDOT:PSS, which simultaneously boosted the power conversion efficiency (PCE) and stability of OSCs based on PBDB-T:N2200. The simultaneous improvement in PCE and stability is originated from the effectively improved light trans-mittance and conductivity of PEDOT:PSS, increased hole extraction of the active layer, as well as the optimized ohmic contact between the interface layer and the electrode. In addition, the TiO2 doping PEDOT:PSS strategy is proved to be general to a variety of OSCs systems, which is expected to bring new opportunities for the devel-opment of high performance HTL, so as to promote the commercialization of OSCs.
通讯机构：
[Chen, Y ] U;Univ South China, Coll Mech Engn, Hengyang 421101, Peoples R China.
关键词：
FeCrAl coating;numerical simulation;temperature field analysis;laser micromelting;laser process parameters;surface morphology
摘要：
Laser micromelting (LMM) technology allows for the remelting of pre-positioned coatings on the surface of a specimen to form a metallurgical bond with the substrate material, significantly improving the coating's film-base bond. However, the high energy input from the laser modification process can cause severe element diffusion, rendering the coating susceptible to deformation and cracking. This can be mitigated by controlling the laser power, scanning speed, and offset of the LMM process. The temperature and stress fields of the samples in the LMM process were analyzed via finite element simulation. The effects of the LMM process parameters on the coating morphology were analyzed in conjunction with experiments. The results indicated that the laser power significantly affected the morphology of the coating after remelting, and a higher scanning speed was more likely to cause the coating to accumulate stress. Additionally, a smaller offset inhibited crack generation. At a laser power of 30 W, a scanning speed of 1200 mm/min, and a scanning spacing of 0.035 mm, the surface of the coating had no obvious defects and was relatively flat, and the adhesion and corrosion resistance were significantly improved. This study provides valuable guidance for improving the preparation of micron-sized protective coatings on Zr alloy surfaces.
关键词：
valley topological refraction;edge state;elastic wave;phononic crystals
摘要：
Valley topological refraction material (TRM) of elastic wave and its direction signal transmittance with robustness against structural disturbance is crucial for various applications such as communication, navigation and detection devices for medical and industrial purpose. However, the existing TRM is limited by the single topological band, which obviously hinders the exploration of the multi-band topological ultrasonic devices to guarantee its efficiency and stability. Here, we demonstrate the dual-band valley TRM for elastic waves, in which the valley edge states and their robustness are investigated. Furthermore, the topological refractions of the valley edge states from the interface into the free space at zigzag termination in two frequency bands are explored, where the mode conversion of the bulk elastic wave occurs at interface termination. Interestingly, the full mode conversion from longitudinal to transverse waves is revealed in the low frequency band while the non-full mode conversion between the longitudinal and transverse takes place in the high frequency band. The researched dual-band elastic TRM could facilitate the potential applications in multi-band and multi-directional devices.
摘要：
Gallium nitride (GaN) is a hard and brittle single crystal and shaping it into thin substrates for semiconductor applications is challenging. The quality of the machined surface can vary depending on the cutting orientation, primarily due to the hexagonal lattice structure of GaN. Therefore, understanding how crystallite orientation affects the cutting performance is crucial before developing a cost-effective machining process for GaN. This study used molecular dynamics (MD) simulation to investigate the cutting of GaN along different crystal orientations. Single grit cutting was performed to validate the simulation results. The simulation revealed distinct outcomes for different cutting directions. When cutting on a-plane or along the [-2110] direction on m-plane, removal efficiency was enhanced due to lower cutting resistance, and more dislocations were generated in the subsurface compared to other cutting directions. However, less phase transition and amorphization were induced, indicating lower energy consumption and smaller forces or stresses involved. Conversely, the cutting on c-plane or along the [0001] direction on m-plane showed the potential for achieving better surface integrity. This study provided valuable insights into the effect of crystallite orientation on the cutting performance of GaN and demonstrated that appropriate selection of cutting directions could result in improved surface quality, which are valuable for developing cost-effective machining technologies for GaN single crystals.
摘要：
Proper disposal of uranium-containing waste is of utmost importance for safeguarding the environment and human health. In this study, we proposed a novel zero-dimensional (0D)/two-dimensional (2D) nanocomposite material, nZVC/Ti(3)C(2), composed of nano zero-valent copper (nZVC) nanoparticles loaded onto Ti(3)C(2) MXene nanoflakes, which was prepared using a simple in situ chemical reduction method. The uniform dispersion of 0D nZVC nanoparticles, with a size of approximately 5nm, onto the 2D ultrathin Ti(3)C(2) MXene effectively prevented agglomeration and corrosion of nZVC. This unique configuration provided numerous adsorption sites for UO(2)(2+)and facilitated a fascinating charge channel for reducing adsorbed UO(2)(2+) into low-mobilized UO(2) by nZVC. Under the synergistic effect of Ti(3)C(2) MXene and nZVC, remarkable efficiency and selectivity of nZVC/Ti(3)C(2) for U (VI) removal were demonstrated, which exhibited an exceptional adsorption capacity of up to 360mg/g, coupled with a high removal efficiency of 97.5% and rapid kinetics. Importantly, the presence of humic acid did not significantly affect the U (VI) removal efficiency of the composite because of the reduction effect of nZVC. The underlying mechanism of U (VI) removal was elucidated, revealing the involvement of reductive immobilization in the form of UO(2) (as high as 73.6%), inner-sphere surface complexation, and hydrolytic precipitation. This mechanism was dependent on the availability of active nZVC and the solution's pH. These findings highlight the potential of nZVC/Ti(3)C(2) composites as efficient decontaminants for radioactive wastewater, thus contributing to advancements in environmental remediation endeavors.
摘要：
This paper investigates the fluid pressure response at the outlet of a vertical fluid delivery straight pipe under random axial vibration. Based on the classical fluid-structure interaction (FSI) 4-equation model and forced vibration theory, the FSI equations of motion of the pipe under random axial vibration are established. Then, the variance of the pressure response at the pipe outlet is solved by combining the pseudo-excitation method and the characteristic line method. The correctness of the proposed method is verified by comparing the results obtained by the proposed method with the Monte Carlo simulation method. Since the pseudo-excitation method can directly obtain the pressure variance without many sample calculations, the method in this paper has high computational efficiency. The influence laws of fluid velocity, pressure, pipe structural parameters, and power spectral density of random vibration on the pressure response of pipe outlet are analyzed. The results show that the effect of random axial vibration on the fluid pressure response at the pipe outlet is significant and cannot be ignored. Increasing the pipe's inner diameter or shortening the pipe's length is beneficial in reducing the fluctuation of the pressure response at the outlet of the pipe. The analytical method in this paper can effectively analyze the outlet pressure of the pipe under random axial excitation and can provide a theoretical basis for reducing the fluid pressure fluctuation in the pipe under random vibration.
摘要：
An effective nonlinear interval sequential quadratic programming method is proposed to provide an efficient tool for uncertain inverse problems. Assisted by the ideology of sequential quadratic programming and dimension -reduction analysis theory, the interval inverse problem is transformed into several interval arithmetic and deterministic optimizations, which could enhance computational efficiency without losing much accuracy. The novelty of the proposed method lies in two main aspects. First, an alternate updating strategy is proposed to identify the radii and midpoints of the interval inputs in each cycle, which could reduce the number of iterative steps. Second, the standard quadratic models are constructed based on the dimension-reduction analysis results, rather than the second-order Taylor expansion. Therefore, the interval arithmetic can be applied to efficiently calculate the interval response, which avoids the inner optimization. Moreover, a novel iterative mechanism is developed to accelerate the convergence rate of the proposed method. Finally, two numerical examples and an engineering application are adopted to verify its feasibility, accuracy and efficiency.
摘要：
Temperature-dependent material attrition and subsurface lattice damage of single-crystal AlN at various scratching depths/forces are investigated at atomic level using molecular dynamics simulation. An ultimate removal precision of depth down to monolayer of AlN is achieved based on the present temperature-dependent critical conditions. The number of worn atoms, positively influenced by temperature due to the reduction of hardness, increases exponentially with increasing normal force in the plastic domain. Archard-type wear coefficient K values calculated at different temperatures increase linearly with normal force, and the slope is independent of temperature. Independently of load and temperature, a wear coefficient normalized with the tangential contact area, K/Atang, is developed to interpret the removal efficiency of AlN substrate with diamond abrasive.
