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Showing 1 to 9 of 9 for “"VSCF"”.
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Accelerating vibrational free energy calculations for anharmonic crystals
… on vibrational self-consistent field theory (VSCF). Firstly, the mathematical framework within which vibrational modelling takes place is detailed. The approximations which must be made are introduced, and the limitations imposed by these approximations are explored. Then the existing …
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Investigating anharmonic effects in condensed matter systems
… many cases. A vibrational self-consistent field (VSCF) method is used as the basis for these calculations, which is then improved and applied to a variety of solid state systems. Firstly, work done to improve the efficiency of the VSCF method is presented. The standard VSCF method involves using …
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Vibrational many-body methods for molecules and extended systems
… of the vibrational self-consistent field (VSCF), vibrational M\o ller--Plesset perturbation (VMP), and vibrational coupled-cluster (VCC) methods on the basis of a QFF in normal coordinates. We have identified algebraically and eliminated several terms in the formalisms of VSCF that have …
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Variable speed constant frequency power conversion with permanent magnet synchronous and switched reluctance generators
… experimentally verified. The efficiency of the VSCF power conversion with a self commutated converter were comparable to the one using a line-commutated converter. A novel converter topology with no dc link capacitor has been proposed for the application of SRMs to the VSCF power conversion. The …
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Theoretical studies of compressed xenon oxides, tin selenide thermoelectrics, and defects in graphene
… the use of a vibrational self-consistent field (VSCF) approach to investigate the effects of nuclear motion and anharmonicity in crystal systems, which involves a local exploration of the Born-Oppenheimer energy surface. The AIRSS crystal structure prediction method is here applied to a study of …
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Modeling, analysis and experimental verification of variable-speed constant-frequency power conversion scheme with a permanent magnet synchronous generator
A variable-speed constant frequency (VSCF) power conversion scheme with a permanent magnet synchronous generator (PMSG) is studied in this dissertation. The scheme consists of a PMSG, diode-rectifier bridge, dc-link filter, controlled converter for conversion to the constant frequency ac utility, …
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Theoretical Investigation of the Structure and Vibrational Frequencies of Water and Methanol Complexes
… intermolecular frequencies than the anharmonic VSCF methods found in GAMESS software. Variational calculations using the quartic polynomials produce estimates of frequencies comparable to the more costly VSCF method. Both the Morse method and polynomial method are very fast computationally …
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Control Strategies for Minimizing the DC-Link Capacitance in Power Electronics Converters for Aircraft Electrical Power Systems
… AC variable speed constant frequency system (VSCF) is investigated. In the VSCF system, the control improvement from the BSG based DC system isused along with a novel adaptive inverter voltage reference (AIVR) algorithm in the four-leg inverter side and to reduce the effects of inverter side …
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Diagrammatic many-body methods for anharmonic molecular vibrational properties
… based on the vibrational self-consistent field (VSCF) approximation, these XVSCF and XVMP2 methods are guaranteed to be size-consistent at the formalism level, meaning that they are applicable not only to small molecules but also to larger systems including condensed phases. The XVSCF method, …