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101.
Foundations of Computational Mathematics - We describe and analyze a randomized homotopy algorithm for the Hermitian eigenvalue problem. Given an $$n\times n$$ Hermitian matrix $$A$$ , the... 相似文献
102.
Mathematical Programming - We study the worst-case performance guarantee of locally optimal solutions for the problem of minimizing the total weighted and unweighted completion time on parallel... 相似文献
103.
Guimaraes Giulia A. A. Lacerda Janiny N. Xing Yutao Ponzio Eduardo A. Pacheco Wagner F. Semaan Felipe S. Dornellas Rafael M. 《Journal of Solid State Electrochemistry》2020,24(8):1769-1779
Journal of Solid State Electrochemistry - This work presents the development and characterization of an electrochemical sensor of tin hexacyanoferrate (SnHCF), produced from the modification by... 相似文献
104.
105.
Ibon Alkorta Felipe Reviriego José Elguero M. Ángeles Monge Enrique Gutiérrez-Puebla 《Structural chemistry》2018,29(1):15-21
Three structures of 2,4,6-tris(1H–pyrazol-1-yl)-1,3,5-triazine (TPT) have been determined at 193 K: the isolated molecule (2a), a solvate containing molecules of water and acetonitrile (2b) and a complex of two molecules of TPT and three molecules of water (2c). To discuss the structures, B3LYP/6–311++G(d,p) calculations have been carried out, in particular, in what concerns hydrogen bonds. 相似文献
106.
The purpose of this paper is to investigate the relationship between cardiac tissue structure, applied electric field, and the transmembrane potential induced in the process of defibrillation. It outlines a general understanding of the structural mechanisms that contribute to the outcome of a defibrillation shock. Electric shocks defibrillate by changing the transmembrane potential throughout the myocardium. In this process first and foremost the shock current must access the bulk of myocardial mass. The exogenous current traverses the myocardium along convoluted intracellular and extracellular pathways channeled by the tissue structure. Since individual fibers follow curved pathways in the heart, and the fiber direction rotates across the ventricular wall, the applied current perpetually engages in redistribution between the intra- and extracellular domains. This redistribution results in changes in transmembrane potential (membrane polarization): regions of membrane hyper- and depolarization of extent larger than a single cell are induced in the myocardium by the defibrillation shock. Tissue inhomogeneities also contribute to local membrane polarization in the myocardium which is superimposed over the large-scale polarization associated with the fibrous organization of the myocardium. The paper presents simulation results that illustrate various mechanisms by which cardiac tissue structure assists the changes in transmembrane potential throughout the myocardium. (c) 1998 American Institute of Physics. 相似文献
107.
Given a continuous function f defined on the unit cube of R~n and a convexfunction _t,_t(0)-0,_t(x)>0,for x>0,we prove that the set ofbest L~(t)-approximations by monotone functions has exactly one elementft,which is also a continuous function.Moreover if the family of convexfunctions {_t}t>0 converges uniformly on compact sets to a function _0,then the best approximation f_t→f_0 uniformly,as t→0,where fo is thebest approximation of f within the Orlicz space L~(0) The best approxima-tions{f_t}are obtained as well as minimizing integrals or the Luxemburgnorm 相似文献
108.
Reviriego F Navarro P García-España E Albelda MT Frías JC Domènech A Yunta MJ Costa R Ortí E 《Organic letters》2008,10(22):5099-5102
The synthesis and steady-state fluorescence studies on the interaction with AMPH, METH, MDMA, and DA of two diazatetraester pyrazole crowns containing appended N-(9H-fluoren-9-yl) and N-(naphth-2-ylmethyl) functions, in a water/ethanol 70:30 mixture at physiological pH, are described. 相似文献
109.
Rodrigo S. Corrêa Felipe T. Martins Javier Ellena Marcelo H. dos Santos Antonio C. Doriguetto 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(7):o395-o397
The asymmetric unit of the title compound, C6H9N2OS2+·HSO4−·H2O, contains a heterocyclic cation, a hydrogen sulfate anion and a water molecule. There are strong hydrogen bonds between the hydrogen sulfate anions and water molecules, forming an infinite chain along the [010] direction, from which the cations are pendent. The steric, electronic and geometric features are compared with those of similar compounds. In this way, structural relationships are stated in terms of the influence of the sulfate group on the protonation of the heterocycle and on the tautomeric equilibrium in the solid state. 相似文献
110.
Today's demand for precisely predicting chemical reactions from first principles requires research to go beyond Gibbs' free energy diagrams and consider other effects such as concentrations and quantum tunneling. The present work introduces overreact, a novel Python package for propagating chemical reactions over time using data from computational chemistry only. The overreact code infers all differential equations and parameters from a simple input that consists of a set of chemical equations and quantum chemistry package outputs for each chemical species. We evaluate some applications from the literature: gas-phase eclipsed-staggered isomerization of ethane, gas-phase umbrella inversion of ammonia, gas-phase degradation of methane by chlorine radical, and three solvation-phase reactions. Furthermore, we comment on a simple solvation-phase acid–base equilibrium. We show how it is possible to achieve reaction profiles and information matching experiments. 相似文献