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The magnetic structure of polymorphic Cr-Co-Ni medium entropy alloys is investigated as a function of temperature and chemical composition by ab initio calculations. Besides the thermal lattice expansion, the longitudinal spin fluctuations (LSFs) are accounted for in determining the magnetic state at finite temperature. We show that sizable local magnetic moments persist on all alloy components in the paramagnetic state for both face-centered cubic and hexagonal close-packed structures, and each alloy species exhibits particular temperature and concentration dependencies. The crucial role of LSFs for the finite temperature magnetic state and its impact on the temperature dependent elastic parameters are demonstrated. Unlabelled Image [ABSTRACT FROM AUTHOR]

The thermodynamic properties of body-centered cubic Nb-V system are well described using the integrated methodology of first-principle calculations, cluster expansion and Monte Carlo simulations, where the contributions from chemical order, lattice distortion and lattice vibration are included. Lattice distortion yields important influence on the phase stability of Nb-V system, while the lattice vibration leads to relatively small effect although the magnitude of vibrational entropy is large compared to the configurational entropy. In addition, lattice distortion also strongly correlates with the order-disorder transition and the degree of short-range order. By accounting for the contributions from chemical ordering, lattice distortion, and lattice vibration, the present first-principle calculations predict a miscibility gap in perfect line with the available experimental data and CALPHAD simulations. The efficient computational methodology adopted in the present work provides a transport route for the effective description of phase stability at finite temperature for complex alloys. • The thermodynamic properties of Nb-V system are effectively described. • The contribution of lattice distortion decreases the transition temperature of Nb-V. • Predicted critical temperature of the miscibility gap agrees well with experiments. [ABSTRACT FROM AUTHOR]

Micro-alloying of Ca in Mg–1Zn-0.3Nd (wt.%) alloy is found to significantly improve tensile strength and process high ductility simultaneously. It closely correlates with grain refinement and the increased coherent nano Mg 2 Ca and (Mg, Zn) 3 Nd precipitates. Ca addition enhances alloying elements co-segregation at grain boundary and promotes grain refinement. Furthermore, nano Mg 2 Ca particles induced by Ca addition can significantly promote the precipitation of (Mg, Zn) 3 Nd phase via the heterogeneous nucleation mechanism owing to their excellent coherency relationship and ultimately lead to the pronounced strengthening effect. In addition, both fine grains and the coherent characteristics between Mg 2 Ca, (Mg, Zn) 3 Nd, and Mg matrix facilitate strain coordination during deformation and yield relatively high ductility. • Micro-alloying Ca in Mg–Zn-Nd alloy significantly increases tensile strength while keeping high ductility. • Ca addition enhances the co-segregation of alloying elements at grain boundary and refines grain size. • Nano Mg 2 Ca particles and the induced (Mg, Zn) 3 Nd precipitates with excellent coherency relationship lead to the pronounced strengthening effect. [ABSTRACT FROM AUTHOR]

Aiming at the problem of low accuracy of person re-identification (Re-ID) algorithm caused by occlusion, low distinctiveness of person features and unclear detail features in complex environment, we propose a Re-ID method based on fine-grained feature fusion and self-attention mechanism. First, we design a dilated non-local module (DNLM), which combines dilated convolution with the non-local module and embeds it between layers of the backbone network, enhancing the self-attention and receptive field of the model and improving the performance on occlusion tasks. Second, the fine-grained feature fusion screening module (3FSM) is improved based on the outlook attention module, which can realize adaptive feature selection and enhance the recognition ability to similar samples of the model. Finally, combined with the feature pyramid in the field of object detection, we propose a multi-scale feature fusion pyramid (MFFP) to improve the Re-ID tasks, in which we use different levels of features to perform feature enhancement. Ablation and comprehensive experiment results based on multiple datasets validate the effectiveness of our proposal. The mean Average Precision (mAP) of Market1501 and DukeMTMC-reID is 92.5 and 87.7%, and Rank-1 is 95.1 and 91.1% respectively. Compared with the current mainstream Re-ID algorithm, our method has excellent Re-ID performance. [ABSTRACT FROM AUTHOR]

This paper deals with a parabolic system with different diffusion coefficients and coupled nonlocal sources, subject to homogeneous Dirichlet boundary conditions. The conditions on global existence, simultaneous or non-simultaneous blow-up, blow-up set, uniform blow-up profiles and boundary layer are got using comparison principle and asymptotic analysis methods. [ABSTRACT FROM AUTHOR]

In this letter, we report an in-situ pre-deposition plasma nitridation process, which is adopted to remove the GaN surface oxygen-related bonds and reduce surface dangling bonds by forming Ga-N bonds prior to the low-pressure chemical vapor deposition (LPCVD)-Si3N4 deposition. It demonstrates that the V \sf {th} hysteresis and current collapse of the device were dramatically improved due to high-quality LPCVD-Si3N4/GaN interface. The MIS-HEMTs using this in-situ pre-deposition plasma nitridation exhibit a very-low V \sf {th} hysteresis of 186 mV at V \text {G-sweep} = (−30 V, +24 V), a high breakdown voltage of 881 V with the substrate grounded. Meanwhile, the MIS-HEMT dynamic R \mathrm{ ON} is only 18% larger than the static R \mathrm{ ON} after OFF-state V \sf {DS} stress of 600 V (the OFF to ON switching time interval is set to 200~\mu \texts ). [ABSTRACT FROM PUBLISHER]

This work reports a high strength and ductility as-casted Mg-9Gd-1.5Y-0.8Zn-0.3Zr (wt.%) alloy by using the optimized heat treatment of a lower solid-solution temperature of 480 ​°C and then aging at 200 ​°C for 48 ​h with the ultimate tensile strength and yield strength reached 374(±2.0) MPa and 270.5(±5.5) MPa, respectively, whilst a high elongation of 10.1(±1.3) % was achieved. The high strength and ductility are found to emerged primarily from the synergic influence of long period stacking ordered (LPSO) phases and the nano-β′ precipitates: at lower temperature of 480 ​°C the alloy preserved a large number of block and lamellar 14H-LPSO phases at the grain boundaries and the smallest size of β′ precipitates led to a better ductility and higher strength. While at higher temperatures solid-solution treatment of 500 ​°C and 520 ​°C, the strength and ductility declined slightly due to the lamellar or filminess LPSO formed in the grains, and especially the precipitation of cubic-shaped RE-enriched phases and rod-like Zn–Zr compounds. Particularly when the solid solution temperature reached as high as 520 ​°C, the strength was significantly reduced due to the increase of the cubic-shaped RE-enriched phases. We suppose that the efficiency of the morphology and position of LPSO phases on the ductility strengthening of the alloy is block and lamellar LPSO phases in the grain boundaries ​> ​lamellar or filminess LPSO phases in the grains. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nd promotes the co-segregation of Zn and Nd at grain boundary combination with the nanoscale (Mg, Zn) 3 Nd precipitates significantly refine the grain size. • Ce significantly enhances the co-segregation of Zn and Ce at the grain boundary and yields a noticeable solute drag effect on the mobility of the grain boundary. • A noticeable improvement in strength and ductility is achieved by Ce addition in Mg-Zn alloy. The role of alloying element segregation at grain boundary on the microstructure and mechanical properties is investigated in the case of Ca, Ce, and Nd addition in Mg-1Zn (wt.%) alloy. Segregation of alloying elements at grain boundary is demonstrated in all the designed ternary alloys, leading to a strong solute drag effect on the mobility of grain boundaries and ultimately the grain size. While the co-segregation of Zn and Ce is revealed in the Mg-Zn-Ce alloy, only the segregation of Zn is observed in the Mg-Zn-Ca alloy. The co-segregation of Zn and Nd in Mg-Zn-Nd alloy is demonstrated to lead to the relatively large solute drag pressure at grain boundary, which in combination with the Zener pressure emerging from nanoscale (Mg, Zn) 3 Nd precipitates significantly refines the grain size. The grain refinement in combination with the bimodal microstructure significantly contributes to the increased strength of the designed ternary alloys. Furthermore, the addition of Ca and Ce are found to simultaneously improve the strength and ductility, which is closely correlated with the segregation of alloying elements at the grain boundary. Among the considered alloying species, Ce is shown to efficiently improve the mechanical properties of Mg-Zn alloy. [ABSTRACT FROM AUTHOR]