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Inese Sarcevica Liana Orola Mikelis V. Veidis Sergey Belyakov 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(4):392-395
A new polymorph of the cinnamic acid–isoniazid cocrystal has been prepared by slow evaporation, namely cinnamic acid–pyridine‐4‐carbohydrazide (1/1), C9H8O2·C6H7N3O. The crystal structure is characterized by a hydrogen‐bonded tetrameric arrangement of two molecules of isoniazid and two of cinnamic acid. Possible modification of the hydrogen bonding was investigated by changing the hydrazide group of isoniazid via an in situ reaction with acetone and cocrystallization with cinnamic acid. In the structure of cinnamic acid–N′‐(propan‐2‐ylidene)isonicotinohydrazide (1/1), C9H8O2·C9H11N3O, carboxylic acid–pyridine O—H...N and hydrazide–hydrazide N—H...O hydrogen bonds are formed. 相似文献
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One-armed bandit models with continuous and delayed responses 总被引:2,自引:0,他引:2
Xikui?WangEmail author Mikelis G.?Bickis 《Mathematical Methods of Operations Research》2003,58(2):209-219
One-armed bandit processes with continuous delayed responses are formulated as controlled stochastic processes following the Bayesian approach. It is shown that under some regularity conditions, a Gittins-like index exists which is the limit of a monotonic sequence of break-even values characterizing optimal initial selections of arms for finite horizon bandit processes. Furthermore, there is an optimal stopping solution when all observations on the unknown arm are complete. Results are illustrated with a bandit model having exponentially distributed responses, in which case the controlled stochastic process becomes a Markov decision process, the Gittins-like index is the Gittins index and the Gittins index strategy is optimal.
Acknowledgement.We thank an anonymous referee for constructive and insightful comments, especially those related to the notion of the Gittins index.Both authors are funded by the Natural Sciences and Engineering Research Council (NSERC) of Canada. 相似文献
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Valdis Laan 《Periodica Mathematica Hungarica》2010,60(1):81-94
Two semigroups are called strongly Morita equivalent if they are contained in a Morita context with unitary bi-acts and surjective
mappings. We consider the notion of context equivalence which is obtained from the notion of strong Morita equivalence by
dropping the requirement of unitariness. We show that context equivalence is an equivalence relation on the class of factorisable
semigroups and describe factorisable semigroups that are context equivalent to monoids or groups, and semigroups with weak
local units that are context equivalent to inverse semigroups, orthodox semigroups or semilattices. 相似文献
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Liana Orola Mikelis V. Veidis Ilpo Mutikainen Reinis Arajs 《Journal of chemical crystallography》2010,40(4):302-305
Abstract
Crystal structures of alpha2-adrenergic antagonist atipamezole base (1) and its hydrochloric acid salt (2) have been determined using X-ray diffraction methods. Atipamezole base crystallized in the monoclinic space group P21, with unit cell parameters a = 13.238(4), b = 9.747(4), c = 14.609(5) ?, β = 107.75(4)o, V = 1,795.3(12) ?3 and Z = 6 (three independent molecules of 1). Atipamezole hydrochloride crystallized in the monoclinic space group Cc, with unit cell parameters a = 12.052(1), b = 32.561(9), c = 13.668(5) ?, β = 102.64(1)o, V = 5,233(2) ?3 and Z = 16 (four independent molecules of 2). Each of the three atipamezole moieties in 1 has an intramolecular C–H···N H-bond. In both structures the molecules are H-bonded to form extended chains. 相似文献7.
Affronte M Troiani F Ghirri A Carretta S Santini P Corradini V Schuecker R Muryn C Timco G Winpenny RE 《Dalton transactions (Cambridge, England : 2003)》2006,(23):2810-2817
We report on real molecular complexes and propose strategies that explore the possibility of implementation of specific quantum computation architectures with molecular spin systems. We focus on Cr3+ carboxylate derivatives and use the Loss-DiVincenzo scheme as reference. 相似文献
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In this paper we study Morita invariants for strongly Morita equivalent semigroups with local units of various kinds. Among others we prove that, under a certain condition of this kind, congruence lattices are preserved by strong Morita equivalence. 相似文献
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Andris Ozols Valdis Kokars Peteris Augustovs Ilze Uiska Kaspars Traskovskis Dmitry Saharov 《Central European Journal of Physics》2011,9(2):547-552
Light polarization effects on a holographic grating recording in a glassy chalcogenide a-As40S15Se45 film has been experimentally studied and compared with previously studied glassy molecular azobenzene film 8a at 633, using s − s,p − p, CE-1 and CE-2 circular-elliptic recording-beam polarizations (differing by light electric field rotation directions). The
azocompound exhibited much higher self-diffraction efficiency (SDE) and diffraction efficiency whereas chalcogenide was more
sensitive. Their recording efficiency polarization dependences also were different. SDE up to 45% was achieved in 8a with p − p and up to 2.6% in a-As40S15Se45 with CE-2 polarized recording beams. The polarization changes in the diffraction process were studied as well in these and
other materials (11, 16, 19 and a-As2S3 film, LiTaO3:Fe crystal). It was found that light polarization changes in the process of diffraction from gratings recorded vectorially
by s−p polarizations depended on chemical composition, wavelength, and exposure time. Vector gratings with SDE up to 25% were recorded
in 8a, rotating a linear polarization by 90°. No light polarization changes were found in azobenzene 19 and chalcogenide films and in LiTaO3:Fe crystal, thus showing a vector recording of scalar holograms. The recording mechanisms in azocompounds and chalcogenides
are discussed and compared. 相似文献
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