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931.
István Deák 《Annals of Operations Research》2011,186(1):83-99
A heuristic procedure, called successive regression approximations (SRA) has been developed for solving stochastic programming problems. They range from equation solving to probabilistic constrained
and two-stage models through a combined model of Prékopa. We show here, that due to enhancements in the computer program,
SRA can be used to solve large-scale two-stage problems with 100 first stage decision variables and a 120 dimensional normally
distributed random right hand side vector in the second stage problem. A FORTRAN source program and computational results
for 124 problems are presented at . 相似文献
932.
933.
934.
935.
J. D. Medina V. De Santis N. Barroeta 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2-3):281-283
Abstract An unexpected nmr spectrum of β-phenyl ethyl thiocyanate in CDCl3 solution has led to its analysis in a series of solvents of increasing polarity. Changes in polarity produce increments of δAB, transforming the signal from a singlet for 4 methylenic protons to a clear A2B2 pattern. Signals appear to split following increasing values of dielectric constants and dipole moments. Rotational isomerism is assumed to be the reason for it since the reaction field parameter depends directly on the dipole moments of rotamers, thus changes in their population affect the reaction field and ultimately the chemical shifts. 相似文献
936.
Whei Oh Lin Vanderléa De Souza 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract As part of our studies in preparation and physical properties of Potential ligands containing l-phosphoryl(P?O)-3-3-carbonyI(C?X, X?NH, O or S) group, we have investigated the intrdinta molecular hydrogen bonding of diisoproxy- phosphorylquanidine[l] as well as the tautomerism of phosphoryl benzylisothiourea. These are of interest as in interpretation of their chelation behavior as well as in development of other potential ligands for specific metal cations. 相似文献
937.
C. A. De Simone E. E. Castellano C. A. Fantin L. B. Zinner G. Vicentini 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4)
Abstract The crystal structure of the complex of formula {|Nd(NCS)3 (HMPA)3‖ |Nd(NCS)3 (HMPA)4|} was determined by three-dimensional X-ray diffraction methods and refined anisotropically to a R=0.040. The compound crystallizes in the trigonal system, space group R3 (No 146), with a=19.947(3), b=19.947(3), c=20.106(3) Å, α=β=90, γ=120°, V=6928(4) Å3, M=1891.4, Z=3, Dc=1.360 g cm?3, λ(MoKα)=0.71073 Å, μ=1.4 cm?1, F (000)=2922.01. There are two independent Nd3+ ions located in the three fold axis. One of them, located at the origin (000) is coordinated to nitrogen atoms of three symmetry related NCS? anions which are below the (x y) plane (negative z) and also to the oxygen atoms of three symmetry related HMPA groups above that plane. The coordination polyhedron is a slightly distorted octahedron. The other Nd3+ ion is located at (00,0.5025(1)). It is coordinated to the nitrogen atoms of three symmetry related NCS? anions above the (xy 1/2) plane and to oxygen atoms of three symmetry related HMPA groups below that plane. Another HMPA group has the O and P atoms located on the three-fold axis, above the (xy 1/2) plane. The coordination number is in this case 7 and the polyhedron is a capped trigonal antiprism. The mean distances are: Nd-N=2.44 Å, Nd-0=2.35 Å and Nd-N=2.52 Å, Nd-0=2.36 Å for the octahedron and antiprism configurations, respectively. (CNPq, FAPESP, FINEP) 相似文献
938.
Hendrik P. Benschop C. A. G. Konings L. P.A. De Jong H. Kienhuis J. Van Genderen 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):345-349
Abstract The four stereoisomers of pinacolyl methylphospho-nofluoridate (soman) were isolated with more than 99% optical purity. The bimolecular rate constants for inhibition of electric eel acetylcholinesterase and the LD50-values (sc, mice) of the stereoisomers were determined. 相似文献
939.
Giovanna Delogu Ottorino De Lucchi Maria Paola Fois Giovanni Valle 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):417-425
Abstract Ketimines la-d derived from ortho-aminosubstituted phenylthioethers were prepared in order to determine the degree of chirality transfer from the chiral auxiliary to the sulfur atom in the formation of the sulfoxide or to the α-carbon atom in the reaction of the anion with alkyl halides or benzaldehyde. Oxidation to the sulfoxide occurred with little or no asymmetric induction. The crystalline benzyl sulfone 4c was deprotonated by alkyllithium or Grignard reagents and reacted with alkyl halides and benzaldehyde, in all cases with little to fair transfer of chirality. The major diastereoisomer from methylation of the anion of 4c with methyl iodide, was isolated, and afforded the enantiomerically pure amine 5 after removal of the chiral auxiliary. An X-ray structure determination of 4d allowed the assignment of the absolute configuration of the asymmetric carbon and revealed that the conformation of the ketimine in the crystal state is not homogeneous. 相似文献
940.
A. Haoudi-mazzah M. Lazraq P. Dhamelincourt Y. Vaugeois R. De Jaeger A. Mazzah 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract Inorganic heterocycles as potential precursors for polymers or solids enjoy continuing interest Eight-membered heterocycle with a Si3O-λ5-P or SiZO4-λ5P skeleton have already been described in the literature1–2 The synthesis, structure, and properties of heterocycles of the Si-O-λ5-P type have been intensively investigated. We present here a simple and convenient synthesis of an eight membered Si2O4-O-λ5P heterocycle and report both its structure and the corresponding vibrational study.3–4 相似文献