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Relaxation of toroidal discharges is described by the principle of minimum energy dissipation together with the constraint
of conserved global helicity. The resulting Euler-Lagrange equation is solved in toroidal coordinates for an axisymmetric
torus by expressing the solutions in terms of Chandrasekhar-Kendall (C-K) eigenfunctions analytically continued in the complex
domain. The C-K eigenfunctions are obtained as hypergeometric functions that are solutions of scalar Helmholtz equation in
toroidal coordinates in the large aspect-ratio approximation. Equilibria are constructed by assuming the current to vanish
at the edge of plasma. For the m=0, n=0 (m and n are the poloidal and toroidal mode numbers respectively) relaxed states, the magnetic field, current, q (safety factor) and pressure profiles are calculated for a given value of aspect-ratio of the torus and for different values
of the eigenvalue λ
r
0. The new feature of the present model is that solutions allow for both tokamak as well as RFP-like behaviour with increase
in the values of λ
r
0, which is related directly to volt-sec in the experiment. 相似文献
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Sandip N.Gavade Ravi S.Balaskar Madhav S.Mane Pramod N.Pabrekar Murlidhar S.Shingare Dhananjay V.Mane 《中国化学快报》2011,22(6):675-678
The coupling reaction of phenylurea with different functionalized aryl halides in the presence of air stable CuI,N,N-dimethylethylenediamine as a ligand,and K3PO4 as a base gives symmetrical and unsymmetrical diarylureas in relatively high yields.This method is milder than the palladium catalyzed arylation and avoids the use of toxic phosphine ligands. 相似文献
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The transport of 2-aminoisobutyric acid (AIB) into liver tissue was increased by both insulin and glucagon. We have now shown that these hormones do not stimulate the same transport system. Glucagon, possibly via cAMP, increased the hepatic uptake of AIB by a mechanism which resembled system A. This glucagon-sensitive system could be monitored by the use of the model amino acid MeAIB. In contrast, the insulin-stimulated system exhibited little or no affinity for MeAIB and will be referred to as system B. On the basis of other reports that the hepatic transport of AIB is almost entirely Na+ dependent and the present finding that the uptake of 2-aminobicyclo [2,2]heptane-2-carboxylic acid (BCH) was not stimulated by either hormone, we conclude that system B is Na+ dependent. Furthermore, insulin added to the perfusate of livers from glucagon-pretreated donors suppressed the increase in AIB or MeAIB uptake. Depending upon the specificities of systems A and B, both of which are unknown for liver tissue, the insulin/glucagon ratio may alter the composition of the intracellular pool of amino acids. 相似文献
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Helane?MS?Costa Augusto?CV?Freitas Júnior Ian?PG?Amaral Izaura?Y?Hirata Patrícia?MG?Paiva Luiz?B?CarvalhoJr Vitor?Oliveira Ranilson?S?BezerraEmail author 《Chemistry Central journal》2013,7(1):166