“Morphotropic phase boundary in pure perovskite lead titanate at room temperature”. Zhang Z, Chen X, Shi X, Hu Y, Huang J, Liu S, Ren Z, Huang H, Han G, Van Tendeloo G, Tian H, Materials Today Nano 20, 100275 (2022). http://doi.org/10.1016/J.MTNANO.2022.100275
Abstract: For many decades, great efforts have been devoted to pursue a large piezoelectric response by an intelligent design of morphotropic phase boundaries (MPB) in solid solutions, where tetragonal (T) and rhombohedral (R) structures coexist. For example, classical PbZrxTi1-xO3 and Pb(Mg1/3Nb2/3)O-3-PbTiO3 single crystals demonstrate a giant piezoelectric response near MPB. However, as the end member of these solids, perovskite-structured PbTiO3 always adopts the T phase at room temperature. Here, we report a pathway to create room temperature MPB in a single-phase PbTiO3. The uniaxial stress along the c-axis drives a T-R phase transition bridged by a monoclinic (M) phase, which facilitates a polarization rotation in the monodomain PbTiO3. Meanwhile, we demonstrate that the coexistence of T and R phases at room temperature can be achieved via an extremely mismatched heterointerface system. The uniaxial pressure is proved as an efficient way to break the inherent symmetry and able to substantially tailor the phase transition temperature Tc. These findings provide new insights into MPB, offering the opportunity to explore the giant piezoelectric response in single-phase materials. (c) 2022 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 10.3
DOI: 10.1016/J.MTNANO.2022.100275
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“3D Eulerian-Eulerian modeling of a screw reactor for biomass thermochemical conversion. Part 1: solids flow dynamics and back-mixing”. Shi X, Ronsse F, Roegiers J, Pieters JG, Renewable energy 143, 1465 (2019). http://doi.org/10.1016/J.RENENE.2019.05.098
Abstract: Three-dimensional (3D) computational fluid dynamics (CFD) simulations were performed to study solids flow dynamics and solids back-mixing behavior in a screw reactor (designed for thermal conversion of dry biomass particles) based on the Eulerian-Eulerian method. Simulation results were compared against experimental data with respect to filling degree and mean residence time of particles. The mean deviations for filling degree and for mean residence time between simulation and experiment were about 0.01 and 11.4 s, respectively, which shows that the model is reasonably accurate in predicting solids flow behavior in the screw reactor. The solids flow dynamics inside the reactor were discussed. The solids residence time distribution (RTD) was calculated and the degree of solids back-mixing in the forward transportation direction of the reactor was analyzed. It was found that solids being flung over the shaft and solids back-leakage, resulting from the low solids forward transportation velocity at the clearance between the flight and the bottom shell of the screw reactor, were responsible for solids back-mixing. The degree of solids back-mixing can be reduced at higher screw rotating speeds when keeping inlet mass flow rate of solids constant. (C) 2019 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.RENENE.2019.05.098
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