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Metal and alloy nanoparticles synthesized by chemical reduction have attracted increasing attention due to their superior physical, chemical, and biological properties. However, most chemical synthesis processes rely on the use of harsh reducing agents and complicated chemical ingredients. Herein, we report a novel reduction-agent-free and surfactant (stabilizer)-free strategy to synthesize Cu, Ag, Au, Cu-Pt, Cu-Au, Cu-Au-Pt-Pd, and Au-Pt-Pd-Cu nanoparticles by ultrasound-assisted dealloying of Mg-based metallic glasses. The formation mechanism of the metal and alloy nanoparticles is revealed by a detailed investigation of sequential intermediate products. We demonstrate that the glass-liquid phase transition of the initially dealloying metallic glasses, together with the synergistic effect of dealloying and ultrasound-driven ligament-breakage of small enough nanoporous intermediates, play key roles in preparing the uniformly dispersed metal and alloy nanoparticles. This approach greatly simplifies the up-scaling synthesis of monometallic and bimetallic nanoparticles, and also provides a general strategy for synthesizing unprecedented multimetallic nanoparticles.

Plate-like Fe-rich intermetallic phases directly influence the mechanical properties of recycled Al alloys; thus, many attempts have been made to modify the morphology of these phases. Through synchrotron X-ray imaging and electron microscopy, the underlying nucleation and growth mechanisms of Fe-rich phases during the solidification of Al-5Ti-1B-modified Al-2Fe alloys were revealed in this study. The results showed that the Al-5Ti-1B grain refiner as well as the applied pressure both resulted in reduction of the size and number of primary Al3Fe phases and promoted the formation of eutectic Al6Fe phases. The tomography results demonstrated that Al-5Ti-1B changed the three-dimensional (3D) morphology of primary Fe-rich phases from rod-like to branched plate-like, while a reduction in their thickness and size was also observed. This was attributed to the fact that Ti-containing solutes in the melts inhibit the diffusion of Fe atoms and the Al3Fe twins produce re-entrant corner on the twin boundaries along the growth direction. Moreover, the TiB2 provides possible nucleation sites for Al6Fe phases. The nucleation mechanism of Fe-rich phases is discussed in terms of experimental observations and crystallography calculations. The decrease in the lattice mismatch between TiB2 and Al6Fe phases was suggested, which promoted the transformation of Al3Fe to Al6Fe phases.

Nanoporous metals prepared by dealloying have attracted increasing attention due to their interesting size-dependent physical, chemical, and biological properties. However, facile fabrication of metallic ultrathin freestanding nanoporous films (UF-NPFs) by dealloying is still challenging. Herein, we report a novel strategy of facile preparation of flexible Cu, Cu3Ag, and CuAg UF-NPFs by dealloying thick Mg-Cu(Ag)-Gd metallic glass ribbons. During dealloying, the local reaction latent heat-induced glass transition of the precursor ribbons leads to the formation of a solid/liquid interface between the initially dealloyed nanoporous layer and the underlying supercooled liquid layer. Due to the bulging effect of in situ generated H2 on the solid/liquid interface, Cu, Cu3Ag, and CuAg UF-NPFs with thicknesses of ∼200 nm can self-peel off from the outer surface of the dealloying ribbons. Moreover, it was found that the surface-enhanced Raman scattering (SERS) detection limit of Rhodamine 6G (R6G) on the Cu and CuAg UF-NPF substrates are 10−6 M and 10−11 M, respectively, which are lower than most of the Cu and Cu-Ag substrates prepared by other methods. This work presents a reliable simple strategy to synthesize a variety of cost effective and flexible metallic UF-NPFs for functional applications.

In this study, powder mixtures at atomic ratios suitable for formation of Sr(Ti0.2Y0.2Zr0.2Sn0.2Hf0.2)O3-x were flash sintered at 1000 °C and 40 mA/mm2. X-ray diffraction and energy-dispersive spectroscopy analyses revealed the formation of single-phase oxides after sintering for 1 min. This rapid formation of single-phase oxide was attributed to flash sintering characteristics, which not only enhanced the diffusion rate, but also softened the lattice. Compared to conventional heat treatment sintering, the sintering time was shortened to 1 min from 10 h, while the sample temperature was reduced to 1314 from 1500 °C. Therefore, flash sintering is a promising technique for rapid synthesis of high-entropy oxides.

Scalable growth of SiC quasi-aligned nanoarrays on SiC wafer substrate was reported through the pyrolysis of polymer precursor by using Au as the catalysts. Differently to the conventional one-dimensional nanostructures often with cylindrical shape, the as-grown SiC nanowires possessed tapered configurations with sharp tips, enabling their desired formation with typical nanoneedle morphology. Their turn-on fields manifested a decline from 3.4 to 1.4 V/μm, when the temperatures were adjusted from room temperature to 400 °C, evidencing their excellent field emission performance. Furthermore, they behaved a high stability with no obvious current emission degradation when subjected to high temperature of 200 °C over 10 h, representing their promising applications in vacuum electronics with robust stability under high-temperature harsh conditions.

A new magnetic Fe36Co22Cr17Ni15Zr10 high entropy amorphous alloy has been prepared and its crystallization behavior and kinetics been studied. The results show that, under non-isothermal conditions, the crystallization activation energy Ex was calculated by the Kissinger equation, which yield 373 kJmol−1. Relation plot of Ex vs crystallization volume fraction(x) manifests the non-isothermal crystallization process is from difficult to easy. On the other hand, base on Arrhenius relation, the crystallization activation energy Ec under isothermal conditions was calculated to be 370 kJmol−1. Relation plot of Ec vs x manifests the isothermal crystallization process is from easy to difficult. The isothermal kinetics was modeled by Johnson-Mehl-Avrami(JMA) equation, as the isothermal annealing temperature increases, the nucleus growth mechanism from diffusion-controlled 3-D growth convert into interface-controlled 3-D growth. Though proper heat treatment, the saturation magnetization Ms of this alloy can reach up to 106.8A∙m2∙kg−1, it will become promising functional materials in the future.

HfO2-based unconventional ferroelectric materials were recently discovered and have attracted a great deal of attention in both academia and industry. The growth of epitaxial Si-doped HfO2 films ha...

In this study, we used pulsed laser deposition to successfully grow epitaxial Hf0.5Zr0.5O2 (HZO) films on (001)-, (011)- and (111)-oriented yttria-stabilized zirconia (YSZ) substrates using TiN as the bottom electrode. It is found that the TiO2 buffer layer formed by the interface reaction is the key to epitaxial growth. The epitaxial HZO films (∼15 nm in thickness) exhibit ferroelectric behaviour with a remnant polarization of 7–30 μC cm−2 and a coercive field of 1.1–2.3 MV cm−1. Using piezoresponse force microscopy, polar domains can be written/read and reversibly switched with a phase change of 180° in all the films. X-ray diffraction and high-resolution transmission electron microscopy reveal the presence of nano domains, and a clear epitaxial relation among different layers whose interfaces are relaxed by reconstruction. X-ray absorption spectroscopy provides deep insight into the microstructural origin of ferroelectricity in HZO. A large interface strain stabilized ferroelectric state is observed which is manifested as the non-centrosymmetric Pca21 phase.

The plate-like Fe-rich intermetallic phases directly influence the mechanical properties of recycled Al alloys, thus many attempts have been made to modify their morphology. Here, through synchrotron X-ray imaging and electron microscopy, we reveal the underlying nucleation and growth mechanism of Fe-rich phases during the solidification of Al-5Ti-1B inoculated Al-2Fe alloys. The experiment results shown that Al-5Ti-1B grain refiner and applied pressure both reduce the sizes and number of primary Al 3Fe phases, and promote the formation of eutectic Al6Fe phases. The tomography results shown that Al-5Ti-1B change the 3D morphology of primary Fe-rich phases from rod-like to branched plate-like and reduced their thickness and size. This is attributed to the Ti-containing solutes in the melts retard the diffusion of Fe atoms and the TiB2 provide possible nucleation sites for Al6Fe phases. The nucleation mechanism of Fe-rich phases is discussed in terms of experimental observation and E2EM model. It is suggested that the V segregated at the TiB2/Al6Fe interface and lower their mismatch and promote the transformation from Al3Fe to Al6Fe phases.

Texture evolution of as-annealed hot rolled Al-Cu-Mg sheets with initial R-Cube {001}〈110〉, R-Cu {112} 〈110〉, and m-Brass {211}〈0,−1,1〉 texture has been studied by X-ray diffraction. Continuous overall texture intensity weakening effect and micro-mechanism, during the isochronal annealing at 280–480 °C for 2 h, was investigated using electron backscatter diffraction and scanning electron micrograph. A new texture fibre {φ1 = 0° − 90°, φ = 65°, φ2 = 63°} has been found. The results show that obvious overall texture intensity weakening started at 400 °C. The texture intensity ratio can be used to depict such weakening trend. Moreover, the overall texture intensity was determined by the reduction of R-Cube at 400–420 °C, but related to the decomposition of Brass at 420–480 °C. Such decomposition of Brass and induced rebound of orientations on the m-fibre, as well as R-Cu texture, due to the near 30°〈111〉 relationship, led to the further overall texture weakening and severe randomization. Keywords: Aluminium alloy, R-Cube, M-fibre, Texture intensity ratio

Texture and microstructure evolution of the 2524 Al-Cu-Mg cold rolled sheet in the annealing at 140–560 °C (for 1 h), was investigated carefully using X-ray diffraction, scanning electron microscopy, and electron backscatter diffraction. The characteristic texture transition rate spectral curve (CTTS), texture index, and orientation streamline approach were utilized to study the successive rules and unknown micro-mechanisms. The results demonstrated that the CTTS could precisely obtain the rule, tendency, and abnormal region of texture evolution within a large temperature range. An abnormal valley zone of texture evolution was observed at 380–440 °C, which is related to the rotation of Cube texture, and huge pinning force from the second phase. The orientation streamline approach effectively revealed the potential evolutional mechanisms of the texture, including α55° {φ1 = 55°, φ = 45°, φ2 = 0°}, Cu35° {φ1 = 35°, φ = 90°, φ2 = 45°}, and F {φ1 = 90°, φ = 55°, φ2 = 45°}. The content of ∑3 twin grain boundary and texture index FCGB weaken each other in the temperature ranges of 320–400 °C and 440–560 °C.

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Texture evolution in hot-rolled Al–Cu–Mg alloy sheets under various temperatures (430 °C, 460 °C, and 490 °C) and values of reduction (50%–90%) has been studied using X-ray diffraction, scanning electron microscopy, electron backscatter diffraction, and Transmission Electron Microscope. The texture index FCGB (texture intensity ratio between cube and brass) was introduced to discuss the semi-quantitative relation between the hot-rolling parameters and orientation composition, and the influence on the final fatigue property of the Al–Cu–Mg T3 sheet. The original orientation streamline approach was used to study the potential texture evolutional mechanisms precisely. The results show that FCGB decreased (≤85%) and then increased (90%) with the hot-rolling reduction gradually at 490 °C. Correspondingly, according to the orientation streamlines, the β-fiber transformed into recrystallization texture owing to the near 30°–40° relation according to the following path: Brass0°→R–Cu→near R-CubeND:22.5°; Brass45°→m-Brass→Brass90° →R-CubeND:22.5°+ R-CubeND:67.5°; Cu→G/BT; Cu→R-Cube and near R-CubeND:22.5°; S→Cube and near R-Cube. High temperature and a large reduction in hot rolling tended to enhance the FCGB and improve the fatigue resistance in the final Al–Cu–Mg T3 sheet.

To explore the characteristics of localization and prognostic implication of Ezrin expression in HCC, 92 cases of HCC meeting strict follow-up criteria were selected for immunohistochemical staining of Ezrin protein. Correlations between Ezrin expression and clinicopathological features of HCC were evaluated using Chi-square tests, survival rates were calculated using the Kaplan-Meier method, and the relationship between prognostic factors and patient overallsurvival was analyzed using Cox proportional hazard analysis. In results, Ezrin protein was mainly expressed in the inner side of the cell membrane of the adjacent non tumor tissues, and diffusely expressed in cytoplasm of HCC tissues. There was an obviously difference between the benign and malignant tissues about the location of Ezrin expression. Ezrin strong-expression rates were significantly higher in HCC samples compared with the adjacent non tumor tissues (P

Voltage source converter multi-terminal DC system(VSC-MTDC) have been used in many applications due to their many advantages. With conventional droop control, the voltage and power of the stable point are on a straight line with a specific slope. When subjected to a power disturbance, the voltage quality may be deteriorated or the power distribution effect of the converter station may be deteriorated. In this paper, a new adaptive control strategy is proposed for VSC-MTDC. The control system focuses on voltage quality at low loads and power distribution at high loads. It not only ensures voltage quality but also meets power distribution requirements. Simulation results are provided to verify the validity and effectiveness of the proposed method.

Modular multilevel matrix converter (M3C) is a competitive frequency converter option to be used in fractional frequency transmission system (FFTS). However, the previous literatures about M3C seldom study its harmonic issue and arm capacitor parameter selection principle. This paper analyzes the harmonic components of the electrical quantities of M3C by circular iteration and provides the principle of the arm capacitor parameters selection. Finally, the validity of the analysis is confirmed by simulation in PSCAD/EMTDC.

The effect of compound fields of ultrasonic vibration and applied pressure (UV+AP) on three-dimensional (3D) microstructure and tensile properties of recycled Al-Cu-Mn-Fe-Si alloys was systematically studied using conventional two-dimensional (2D) microscopy, synchrotron X-ray tomography, and tensile test. The properties of UV+AP treated alloys with the pouring temperature of 740, 710 and 680 &deg, C were compared when those alloys achieved after gravity casting. After UV+AP treatment, the alloy with pouring temperature of 710 &deg, C show the smallest grain size. Also, the sizes of Fe-rich phases and Al2Cu are greatly reduced and their 3D morphologies are compacted. The mechanical properties of UV+AP treated alloys are relatively higher than those measured for gravity cast equivalents. This improvement can be explained by the synergistic effect of acoustic cavitation, acoustic streaming, and force-feeding, which resulted in the dendrite fragmentation, uniform solute distribution, and microstructural refinement. The Orowan strengthening and solution strengthening were identified as the main strengthening mechanisms.