Tin diselenide (SnSe2) nanosheets as novel 2D layered materials have excellent optical properties with many promising application prospects, such as photoelectric detectors, nonlinear optics, ...infrared photoelectric devices, and ultrafast photonics. Among them, ultrafast photonics has attracted much attention due to its enormous advantages; for instance, extremely fast pulse, strong peak power, and narrow bandwidth. In this work, SnSe2 nanosheets are fabricated by using solvothermal treatment, and the characteristics of SnSe2 are systemically investigated. In addition, the solution of SnSe2 nanosheets is successfully prepared as a fiber‐based saturable absorber by utilizing the evanescent field effect, which can bear a high pump power. 31st‐order subpicosecond harmonic mode locking is generated in an Er‐doped fiber laser, corresponding to the maximum repetition rate of 257.3 MHz and pulse duration of 887 fs. The results show that SnSe2 can be used as an excellent nonlinear photonic device in many fields, such as frequency comb, lasers, photodetectors, etc.
Tin diselenide (SnSe2) nanosheets as novel 2D layered materials have excellent optical properties. SnSe2 nanosheets fabricated by using solvothermal treatment are successfully prepared as fiber‐based saturable absorbers by utilizing the evanescent field effect, which can bear a high pump power. 31st‐order subpicosecond harmonic mode‐locking is generated, corresponding to 257.3 MHz repetition rate.
A novel Mg-8Al-2Sn-1Zn alloy with a bimodal structure prepared by hard-pate-rolling (HPR) exhibits both higher tensile strength and ductility than its fine-grained counterparts prepared by ...conventional rolling. By delicate electron back-scatter diffraction (EBSD) analysis, we found fine grains with weak basal texture is beneficial for basal slip and favors initial deformation. Meanwhile, coarse grains with a strong basal texture could accommodate abundant newly generated dislocations, promoting work hardening after fine grains are saturated with dislocations. For the first time, individual roles of fine and coarse grains and their synergy effect on enhancing ductility in bimodal structured Mg alloys is clarified.
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•A bimodal grain-structured Mg alloy is fabricated by hard-pate-rolling.•The bimodal sample has higher strength and ductility than fine-grained samples.•The synergy effect of fine and coarse grains on enhancing ductility is clarified.
Aluminum matrix composites (AMCs) reinforced with the nano‐sized particles are very important materials for the applications in industrial fields. These aluminum matrix composites consist of an ...aluminum matrix and nano‐sized particles, which own very different physical and mechanical properties from those of the matrix. Nano‐sized particles show a more obvious strengthening effect on the matrix than the micro‐sized particles do, because of the high specific surface area which is positive for the pinning effect during the deformation process. Thus, the nano‐sized particle‐reinforced AMCs usually exhibit a good ductility. The main issues of the fabrication methods are the low wettability between the nano‐sized particles and the molten aluminum alloys, which is fatal to the conventional casting methods, and the agglomeration of nano‐sized particles which happened easier than the larger particles. Several alternative processes have been presented in literature for the production of the nano‐sized particle‐reinforced aluminum composites. This paper is aimed at reviewing the feasible manufacturing techniques used for the fabrication of nano‐sized particle‐reinforced aluminum composites. More importantly, the strengthening mechanisms and models which are responsible for the improvement of mechanical properties of the nano‐sized particle‐reinforced aluminum composites have been reviewed.
Aluminum matrix composites reinforced with the nano‐sized particles are very important materials due to the good mechanical properties. This paper aims to review the feasible manufacturing techniques of the nano‐sized particle‐reinforced aluminum composites and the strengthening effects of the nano‐sized particles in Al matrix systematically.
Comprehensive Summary
Crosslinked liquid crystal polymers (CLCPs) are smart materials that combine the anisotropy of liquid crystals (LCs) with the elasticity of rubber. When subjected to external ...stimuli, they exhibit exceptional two‐way shape memory behavior. Among the various stimuli, electrical energy has the advantages of cleanliness, stability, and high controllability; hence, it is widely used for controlling CLCP‐based soft actuators, thus presenting potential for application in diverse, complex scenarios. By combining electrically driven mode and sensor equipment, precise control of CLCPs can be achieved, and the electrically driven CLCPs can accomplish more intricate and sophisticated tasks. This study presents a comprehensive review of electrically driven CLCPs with various driving mechanisms, including the electroclinic effect of ferroelectric CLCPs, the reorganization of LC molecules, the Maxwell effect of dielectric CLCPs, and the Joule heating effect of electrothermally responsive CLCP systems. In addition, a detailed analysis of the applications of electrically driven CLCPs in various research fields is presented. Finally, the current challenges in the field of electrically driven CLCP technology are summarized, along with predictions for future prospects.
The development of an efficient catalyst for formic acid electrocatalytic oxidation reaction (FAEOR) is of great significance to accelerate the commercial application of direct formic acid fuel cells ...(DFAFC). Herein, palladium phosphide (PdxPy) porous nanotubes (PNTs) with different phosphide content (i.e., Pd3P and Pd5P2) are prepared by combining the self‐template reduction method of dimethylglyoxime‐Pd(II) complex nanorods and succedent phosphating treatment. During the reduction process, the self‐removal of the template and the continual inside–outside Ostwald ripening phenomenon are responsible for the generation of the one‐dimensional hollow and porous architecture. On the basis of the unique synthetic procedure and structural advantages, Pd3P PNTs with optimized phosphide content show outstanding electroactivity and stability for FAEOR. Importantly, the strong electronic effect between Pd and P promotes the direct pathway of FAEOR and inhibits the occurrence of the formic acid decomposition reaction, which effectively enhances the FAEOR electroactivity of Pd3P PNTs. In view of the facial synthesis, excellent electroactivity, high stability, and unordinary selectivity, Pd3P PNTs have the potential to be an efficient anode electrocatalyst for DFAFC.
Efficient formic acid oxidation reaction (FAEOR) electrocatalyst Pd3P porous nanotubes (PNTs) are synthesized by simple self‐template pyrolysis and phosphating treatment. Benefiting from the abundant defect atoms and excellent self‐stability, Pd3P PNTs reveal outstanding electroactivity and durability for FAEOR. The introduction of phosphorus could effectively improve the FAEOR electroactivity of Pd nanomaterials and simultaneously inhibit FADR, highlighting an efficient strategy for designing a DFAFC anode electrocatalyst.
Nano-sized ceramic particle reinforced aluminum composites exhibit excellent room-temperature mechanical properties. However, there is limited research on the dry sliding wear behavior of those ...composites at elevated temperatures, which should be one of the major concerns on elevated temperature applications. Here the Al-Cu composites reinforced with nano-sized TiCp were fabricated. The dry sliding wear behaviors of the nano-sized TiCp/Al-Cu composites at various temperatures (140–220 °C) and loads (10–40 N) with different TiCp contents were studied, and the results showed that the nanocomposites exhibited superior wear resistance. For instance, the relative wear resistance of the 0.5 wt.% nano-sized TiCp/Al-Cu composite was 83.5% higher than that of the Al-Cu matrix alloy at 180 °C under 20 N, and was also 16.5% higher than that of the 5 wt.% micro-sized TiCp/Al-Cu composite, attributed to the pronounced Orowan strengthening effect of nanoparticles. The wear rates of the nanocomposites were always lower than those of the Al-Cu matrix alloy under the same test condition, which increased with the increase in temperature and load and with the decrease in TiCp content.
Abstract
To make the hydraulic jack meet the requirements of modern mechanical and electrical equipment, such as intelligence, high sensitivity, and good operation performance, this paper presents ...the design of an embedded measurement and control system for a small electric mechanical airplane jack. A new type of electric mechanical jack is designed. According to its need for strong maneuverability, a new intelligent jack measurement, and control system based on the C8051F410 single-chip microcomputer is developed. The system mainly takes the stepping motor as the power source, and the selection requirements, the parameter design of stepping motors, and their supporting drivers and controllers are mainly introduced through the control of multiple stepper motors. Two schemes are listed in the selection of controllers, and the second scheme is selected according to the actual operational needs of the system. It can control the movement of the jack, such as fast-forward, working, and walking. The test system also realizes the load stress signal of the key parts of the jack support arm, as well as the real-time acquisition and display of the height displacement signal during work. The performance of the control part of the jack control system and part of the acquisition system was verified through experiments. The experimental results prove that the system meets the design requirements of the system and the actual design requirements.
There is an increasingly urgent need of lightweight components in aerospace industry, among which aluminum (Al) alloys have been the optimal materials of choice for aircraft structural parts since ...being used in the Junkers F.13 aircraft in the 1920s. Compared to other metal materials, Al alloys have a lower density, and the use of Al alloys reduces the total weight of the aircraft and improves fuel efficiency and load capacity. Meanwhile, the strength and hardness of Al alloys with alloying and heat treatment can be significantly enhanced for uses in high loads and vibration environments. Furthermore, in the harsh aerospace environment, aircraft may receive various climatic conditions and chemical corrosion. Due to good corrosion and fatigue resistance, Al alloys demonstrate excellent performance under these conditions, ensuring the long–term service life of aircraft. In addition, Al alloys have good recyclability, and they can be recycled to reduce resource consumption and environmental load, in line with the principle of sustainable development. In recent years, although composites have been widely used in aerospace, high–strength Al alloys are still in an indispensable position. Therefore, this article reviews the progress and applications of Al alloys commonly used in aerospace. The common strengthening methods and advanced manufacturing and processing technologies of Al alloy are also discussed, which can provide references for the development of advanced high–performance aviation Al alloys in the future.
Small‐molecule electrooxidation‐boosted water electrolysis (WE) is an energy‐saving method for hydrogen (H2) production. Herein, PdPt bimetallenes (PdPt BMLs) are obtained through the simple galvanic ...replacement reaction. PdPt BMLs reveal 2.93‐fold enhancement in intrinsic electroactivity and 4.53‐fold enhancement in mass electroactivity for the formate oxidation reaction (FOR) with respect to Pd metallenes (Pd MLs) at 0.50 V potential due to the synergistic effect. Meanwhile, the introduction of Pt atoms also considerably increases the electroactivity of PdPt BMLs for hydrogen evolution reaction (HER) with respect to Pd MLs in an alkaline medium, which even exceeds that with the use of commercial Pt nanocrystals. Inspired by the outstanding FOR and HER electroactivity of bifunctional PdPt BMLs, a two‐electrode FOR‐boosted WE system (FOR‐WE) is constructed by using PdPt BMLs as the cathode and the anode. The FOR‐WE system only requires an operational voltage of 0.31 V to achieve H2 production, which is 1.48 V lower than that (ca. 1.79 V) with the use of the traditional WE system.
PdPt bimetallenes (PdPt BMLs) are synthesized by a galvanic replacement reaction, which leads to enhancement of intrinsic electroactivity for both the formate oxidation reaction and the hydrogen evolution reaction with respect to Pd metallence due to the synergistic effect. Also, the PdPt BMLs||PdPt BMLs formate electrolyzer requires an operational voltage of only 0.31 V for H2 production, which is 1.48 V lower than that of the traditional water electrolysis system.
Effects of Zn addition on the microstructure and tensile properties of as-extruded Mg-8Al-2Sn (AT82) alloy were investigated in the present work. All the extruded AT82 alloys exhibited a fully ...dynamically recrystallized (DRXed) microstructure, while the grains were slightly refined with Zn addition. Moreover, second phase particles (Mg2Sn and Mg17Al12) increased significantly in amount with increasing Zn content. It was found the ultimate tensile strength (UTS) and yield strength (YS) gradually increased with increasing Zn content from 0 to 1.5wt%, meanwhile the elongation maintained unchanged at a high level, i.e. ~17–19%. In particular, the as-extruded AT82-1.0Zn alloy exhibited both a high strength and high ductility at room temperature, e.g. UTS of ~357MPa and elongation of ~19%. The superior combination of strength and ductility is mainly benefited from the enhanced work-hardening ability resulted from Zn solid solutes and the presence of more well-dispersed fine particles in AT82-1.0Zn alloy.
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