The thermal shock of subsurface material with shear instability and severe plastic flow during scuffing was *** scuffing damage of M50 steel was tested using a high-speed rolling-sliding contact test rig,and the trans...
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The thermal shock of subsurface material with shear instability and severe plastic flow during scuffing was *** scuffing damage of M50 steel was tested using a high-speed rolling-sliding contact test rig,and the transient temperature during scuffing was calculated using the Fourier transform method considering the effects of both frictional heat and plastic *** results show that a thermal shock with a rapid rise and subsequent rapid decrease in the contact temperature is generated in the subsurface *** frictional power intensity generates a high temperature rise,leading to the austenitization of the subsurface ***,the plastic flow is generated in the subsurface layer under the high shear stress,and the resulting plastic strain energy generates a further temperature ***,a rapid decrease in the contact temperature quenches the material,resulting in clear shear slip bands and retained austenite in the subsurface layers of the M50 steel.
The instability of nanograined metals and the degradation of their mechanical properties primarily arise from pronounced grain boundary(GB) sliding and migration at extremely small grain sizes(GS). This study explores...
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The instability of nanograined metals and the degradation of their mechanical properties primarily arise from pronounced grain boundary(GB) sliding and migration at extremely small grain sizes(GS). This study explores the incorporation of carbon nanotubes(CNTs) into nanocrystalline metals to enhance plastic flow stress by impeding metal deformation. The results demonstrate that CNTs increase the critical stress of pure polycrystalline metals as GS increases. The relationship between plastic flow stress and GS in the composites is modeled using Hall-Petch and inverse Hall-Petch frameworks. As GS increases, the dominant plastic strengthening mechanism transitions from GB sliding hindrance via CNTs to a combined effect that mitigates GB sliding and intragranular stacking faults. Additionally, the study evaluates how CNT length, wall number, and functionalization influence plastic strengthening. Hence, these findings provide a theoretical foundation for the design of mechanically stable nanocrystalline metal composites.
We proposed a low-complexity multi-input multi-output neural network integrated with a maximum likelihood phase recovery algorithm (MIMO-NN-BMLPR), which is adopted in long-haul coherent optical communication. Neural ...
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This study focused on the microscopic strengthening and failure mechanisms of the Al matrix reinforced by graphene(Gr), and the effects of number of layers, chirality, and arrangement of Gr were calculated based on th...
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This study focused on the microscopic strengthening and failure mechanisms of the Al matrix reinforced by graphene(Gr), and the effects of number of layers, chirality, and arrangement of Gr were calculated based on the molecular dynamics simulation. The results revealed that the Young's modulus and yield strength were significantly enhanced by the addition of Gr. In Gr/Al composites with monolayer Gr, the zigzag Gr exhibited a better ultimate strain than the armchair Gr, indicating that the plastic deformation was affected by the chirality, and the dislocation hindrance and load transfer were the dominated strengthening mechanisms. The crack in the armchair Gr was limited to follow straight paths, while that in zigzag Gr extended in a petal-like manner across multiple directions. In Gr/Al composite with multilayer Gr, the dispersing Gr showed a stronger strengthening effect than the stacking Gr, and the strengthening effect increased with increasing the volume fraction of Gr. The dispersing Gr strongly hindered the movement of dislocations, while the Al matrix in the composite with stacking Gr could retard the folding of Gr. Moreover, Gr nanosheets fractured layer by layer rather than simultaneously fractured in the Gr/Al composites with multilayer Gr.
The advancement of terahertz (THz) communication technology drives the evolution of wireless communication systems,offering novel pathways and technical means for the development of future 6G communication *** wireles...
The advancement of terahertz (THz) communication technology drives the evolution of wireless communication systems,offering novel pathways and technical means for the development of future 6G communication *** wireless communication systems are often constrained by bandwidth limitations of electronic devices in high frequency ***,THz communication technology leverages the characteristics of electromagnetic waves to transcend these limitations,enabling communication athigher frequencies and wider bandwidths.
The failure of electrical equipment directly or indirectly caused by overheating has become one of the main reasons for equipment *** real-time condition monitoring method of electrical equipment based on digital twin...
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The failure of electrical equipment directly or indirectly caused by overheating has become one of the main reasons for equipment *** real-time condition monitoring method of electrical equipment based on digital twin(DT)has received extensive attention and is considered as a technology with great engineering values and excellent application ***,the current calculation of DT mostly relies on the traditional finite element method(CFEM).This method becomes less computationally efficient as the size of the DT increases,especially for electrical equipment with high *** is difficult to meet the requirements real-time calculation in ***,starting from the algorithm optimization and parallel architecture,based on the weighted residual method and stabilised conforming nodal integration,a novel discrete method of electrothermal coupling equation is proposed and the data storage structure of the algorithm from the bottom layer is redesigned,and the corresponding GPU and multi-core CPU parallel framework are ***,taking the high voltage bushing as an example,the correctness of the method in this paper is verified by the CFEM code and commercial software *** the same grid and accuracy requirement,the calculation time is shortened by at least five times than *** the method is easy to extend to other types of multi-physics calculations.
Semantic segmentation is pivotal in autonomous train perception, significantly impacting the system's intelligence and reliability. However, its performance in railway scenes is hindered by various challenges, inc...
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Identifying the real fracture of rock hidden in acoustic emission(AE)source clusters(AE-depicted microcrack zone)remains challenging and *** we revealed the AE energy(representing dissipated energy)distribution rule i...
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Identifying the real fracture of rock hidden in acoustic emission(AE)source clusters(AE-depicted microcrack zone)remains challenging and *** we revealed the AE energy(representing dissipated energy)distribution rule in the rock microcrack zone and proposed an AE-energy-based method for identifying the real fracture.(1)A set of fracture experiments were performed on granite using wedgeloading,and the fracture process was detected and recorded by *** microcrack zone associated with the energy dissipation was characterized by AE sources and energy distribution,utilizing our selfdeveloped AE analysis program(RockAE).(2)The accumulated AE energy,an index representing energy dissipation,across the AE-depicted microcrack zone followed the normal distribution model(the mean and variance relate to the real fracture path and the microcrack zone width).This result implies that the nucleation and coalescence of massive cracks(i.e.,real fracture generation process)are supposed to follow a normal distribution.(3)Then,we obtained the real fracture extension path by joining the peak positions of the AE energy normal distribution curve at different cross-sections of the microcrack ***,we distinguished between the microcrack zone and the concealed real fracture within *** deviation was validated as slight as 1–3 mm.
This article explores the trajectory tracking problem of an Autonomous Surface Vessel (ASV). As an optimization-based time-domain method, Model Predictive Control (MPC) has incomparable advantages in solving constrain...
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Electrohydrodynamic(EHD)printing has critical merits in micro/nanoscale additive manufacturing because of its ultrahigh resolution and wide ink compatibility,making it an advantageous choice for electronics manufactur...
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Electrohydrodynamic(EHD)printing has critical merits in micro/nanoscale additive manufacturing because of its ultrahigh resolution and wide ink compatibility,making it an advantageous choice for electronics manufacturing,high-resolution prototyping,and biological component ***,EHD printing is currently limited by its rather low throughput due to the lack of high-frequency and high-density multi-nozzle *** paper presents a novel EHD printhead with a protruding polymer-based nozzle *** insulated,hydrophobic,and protruding polymer nozzle array with an appropriate geometric structure can effectively address key problems in multi-nozzle jetting,such as electrical crosstalk,electrical discharge,liquid flooding,and nonuniform *** investigating the influence of the electrical and geometric characteristics of the nozzle arrays on the electrical crosstalk behavior and fabricating the optimized nozzle array via MEMS technology,we achieve an EHD printhead with a large scale(256),high density(127 dpi),and high jetting frequency(23 kHz),and addressable jetting can be realized by adding independently controllable extractors underneath the nozzle *** functional materials,such as quantum dots,perovskite,and nanosilver inks,can be ejected into high-resolution patterns through the optimized nozzle array,demonstrating the great prospects of our designed printhead in electronics *** MEMS-compatible printhead design lays the foundation for high-throughput fabrication of micro/nanostructures and promotes practical applications of EHD printing in functional electronics and biomedical/energy devices.
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