We report on an extensive study of ZnO materials with cagelike motifs in clusters and bulk phases through structural searches using the minima hopping method. A novel putative ground state was discovered for the (ZnO)...
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We report on an extensive study of ZnO materials with cagelike motifs in clusters and bulk phases through structural searches using the minima hopping method. A novel putative ground state was discovered for the (ZnO)32 cluster with a tubelike structure, closely related to the previously reported (ZnO)24 ground-state cage geometry. Furthermore, the effect of ionization on the geometries and energetic ordering of (ZnO)n clusters with n=3–10,12 was studied by directly sampling the energy landscape of the ionized system. Our results indicate that the transition from ring and planar structures to three-dimensional cages occurs at larger cluster sizes than in the neutral system. Inspired by the bottom-up design philosophy and the predominance of cagelike structures in medium-sized clusters, a search for crystalline ZnO was conducted aimed specifically at low-density polymorphs, resulting in the discovery of 57 novel metastable phases. The voids in these low-density materials closely resemble the hollow cage structures of small (ZnO)n/(ZnO)n+ clusters with n<16. Analogous to clathrate materials, these voids could serve to accommodate guest atoms to tailor the materials properties for various applications.
We consider the scaling properties characterizing the hyperuniformity (or anti-hyperuniformity) of long wavelength fluctuations in a broad class of one-dimensional substitution tilings. We present a simple argument th...
Polybenzimidazole (PBI) membranes with nanophase-separated structure induced by non-ionic hydrophilic side chain are designed and fabricated for vanadium flow batteries (VFBs). The designed PBI membranes are prepared ...
Polybenzimidazole (PBI) membranes with nanophase-separated structure induced by non-ionic hydrophilic side chain are designed and fabricated for vanadium flow batteries (VFBs). The designed PBI membranes are prepared by grafting non-ionic hydrophilic side chains via an N-substitution reaction. This molecular modification induces nanophase separation and formation of hydrophilic clusters, which act as effective proton transfer pathways, hence dramatically improving the proton conductivity. Meanwhile, the vanadium permeability is inappreciable due to the appropriate size of hydrophilic clusters and Donnan exclusion of protonated grafted-PBI membranes (GPBI). Free from ion exchange groups, GPBI membranes maintain the good chemical stability of the pristine PBI membrane. As a result, the designed membrane exhibits an impressive performance, combining ultrahigh proton conductivity, ion selectivity and chemical stability. The GPBI-based VFB exhibits a coulombic efficiency of over 99% and an energy efficiency of 84% at 120 mA cm−2, the highest reported for dense PBI membranes for VFB applications. The decent stability of GPBI membranes is demonstrated by the stable performance over 200 charge–discharge cycles and the ex situ immersion test. This work provides a new insight into the design of high-performance PBI membranes for VFB applications.
Tree architecture has evolved to support a top-heavy above-ground biomass, but this integral feature poses a weight-induced challenge to trunk stability. Maintaining an upright stem is expected to require vertical pro...
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We propose a theory based on non-equilibrium thermodynamics to describe the mechanical behavior of an active polymer gel created by the inclusion of molecular motors in its solvent. When activated, these motors attach...
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We present measurements of the low temperature thermal conductivity for materials useful in the construction of cryogenic supports for scientific instrumentation and in the fabrication of flat flexible cryogenic cabli...
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The ability to control magnetism in sub-picosecond timescales using laser pulses has potential applications in fast magnetic devices. It has been demonstrated that a single femto-second laser pulse can reverse the mag...
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ISBN:
(纸本)9781538632918
The ability to control magnetism in sub-picosecond timescales using laser pulses has potential applications in fast magnetic devices. It has been demonstrated that a single femto-second laser pulse can reverse the magnetization of a film within a few picoseconds [1], a phenomenon called as all-optical switching (AOS). However, this phenomenon thus far has been observed only in ferrimagnetic GdFeCo films. On the other hand, ferromagnetic films, which are of greater interest than ferrimagnets in many technological applications, need multiple laser pulses for magnetization reversal [2], making the overall effect slow and energy inefficient. Fast, single-shot switching of a ferromagnet can open up new avenues for spintronic devices that operate at unprecedented picosecond timescales, thereby making them viable non-volatile replacements for silicon based RAMs and logic devices.
Survival rate (SR) and growth rate (GR) were tested with various feed sources to identify an appropriate feed to improve the productivity in the early life stage of the rock worm Marphysa sanguinea (Montagu, 1813) (Eu...
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