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Schumer J.W. Swanekamp S.B. Ottinger P.F. Commisso R.J. Weber B.V. Smithe D.N. Ludeking L.D. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2001,29(3):479-493
The plasma opening switch (POS) is a critical element of some inductive-energy-storage pulsed-power generators. Detailed understanding of plasma redistribution and thinning during the POS conduction phase can be gained through magnetohydrodynamic fluid (MHD) simulations. As space-charge separation and kinetic effects become important late in the conduction phase (beginning of the opening phase), MHD methods become invalid and particle-in-cell (PIC) methods should be used. In this paper, the applicability of MHD techniques is extended into PIC-like regimes by including nonideal MHD phenomena such as the Hall effect and resistivity. The feasibility of the PIC technique is, likewise, extended into high-density, low-temperature-MHD-like regimes by using a novel numerical cooling algorithm. At an appropriate time, an MHD-to-PIC transition must be accomplished in order to accurately simulate the POS opening phase. The mechanics for converting MHD output into PIC input are introduced, as are the transition criteria determining when to perform this conversion. To establish these transition criteria, side-by-side MHD and PIC simulations are presented and compared. These separate simulations are then complemented by a proof-of-principle MHD-to-PIC transition, thereby demonstrating this MHD-to-PIC technique as a potentially viable tool for the simulation of POS plasmas. Practical limitations of the MHD-to-PIC transition method and applicability of the transition criteria to hybrid fluid-kinetic simulations are discussed 相似文献
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E.H Auerbach A.J Baltz C.B Dover A Gal S.H Kahana L Ludeking D.J Millener 《Annals of Physics》1983,148(2):381-435
A comprehensive shell-model approach to Λ-hypernuclear spectroscopy in the p shell is developed. The available data on the spectra of 9ΛBe, 12ΛC, 13ΛC, 14ΛN and 16ΛO are interpreted in this framework, leading to constraints on the residual ΛN interaction and the one-body Λ-nucleus potential. The mechanism for the formation of Λ hypernuclei via the (K?, π?) reaction is treated in the relativistic distorted wave approximation, with careful attention paid to Fermi-averaging of the elementary K?n → π?Λ amplitude and recoil corrections. Departures from the simple weak coupling picture, arising from configuration mixing, are emphasized. This leads to approximate dynamical symmetries in hypernuclei which are forbidden in ordinary nuclei by the Pauli principle. Further experiments in the p shell are suggested which may reveal other aspects of ΛN interactions. 相似文献
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Arunmozhiarasi Armugam Charmian DN Cher KaiYing Lim Dawn CI Koh David W Howells Kandiah Jeyaseelan 《BMC neuroscience》2009,10(1):120
Background
Phospholipase A2 liberates free fatty acids and lysophospholipids upon hydrolysis of phospholipids and these products are often associated with detrimental effects such as inflammation and cerebral ischemia. The neuroprotective effect of neutral phospholipase from snake venom has been investigated. 相似文献4.
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