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61.
Rodrigo E Morales S Duce S Ruano JL Cid MB 《Chemical communications (Cambridge, England)》2011,47(40):11267-11269
Heteroarylvinyl sulfone 1 has been successfully used as a new sulfonyl Michael acceptor in aminocatalytic reactions with branched aldehydes. Subsequent one-pot Julia-Kocienski olefination allows the challenging preparation of enantiomerically pure α-allylated aldehydes bearing C-α quaternary carbons. 相似文献
62.
Costa EV Pinheiro ML de Souza AD Barison A Campos FR Valdez RH Ueda-Nakamura T Filho BP Nakamura CV 《Molecules (Basel, Switzerland)》2011,16(11):9714-9720
Phytochemical investigation of the branches of Annona foetida Mart. led to isolation from the CH(2)Cl(2) extract of four alkaloids: Atherospermidine (1), described for the first time in this species, liriodenine (2), O-methylmoschatoline (3), and annomontine (4). Their chemical structures were established on the basis of spectroscopic data from IR, MS, NMR (1D and 2D), and comparison with the literature. Compounds 2-4 showed potent trypanocidal effect when evaluated against epimastigote and trypomastigote forms of Trypanosoma cruzi. 相似文献
63.
Storm processes and stochastic geometry 总被引:1,自引:0,他引:1
This paper is devoted to a prototype of max-stable models called the storm process. At first its spatial distribution is given
in association with different observation supports. Then the compatibility relationships between extremal coefficients at
various supports are completely characterized. Particular attention is paid to the special case where the storms are indicator
functions of Poisson polytopes. Explicit formulae are found for the extremal coefficients with finite or convex supports.
A new algorithm for exactly simulating the Poisson storm process in continuous space is also provided. Overall, the storm
process can be used as a benchmark for comparing the performances of several estimators of extremal coefficients, or for model
selection. 相似文献
64.
M. Beláková E. Havránek A. Bumbálová 《Journal of Radioanalytical and Nuclear Chemistry》1995,201(5):431-437
Determination of Mn, Fe, Cu, Zn, Hg, Pb, Br, Se, Rb, Sr and Cd in the medicinal plants by radionuclide X-ray fluorescence analysis (using238Pu,241Am/Ag and125I) is described. 相似文献
65.
66.
67.
V. A. Andronov S. A. Bel’kov A. V. Bessarab I. N. Voronich S. G. Garanin A. A. Gorbunov V. N. Derkach G. V. Dolgoleva A. I. Zaretskii V. M. Izgorodin B. N. Ilyushechkin G. A. Kirillov G. G. Kochemasov Yu. V. Kuratov V. I. Lazarchuk V. A. Lebedev V. M. Murugov L. S. Mkhitar’yan A. V. Okutin S. I. Petrov A. V. Pinegin N. N. Rukavishnikov A. N. Razin A. V. Ryadov A. V. Senik N. A. Suslov S. A. Sukharev V. A. Tokarev 《Journal of Experimental and Theoretical Physics》1997,84(3):485-488
The results of the first experiments devised to investigate the mixing of thin layers of Al and Au during the laser acceleration
of flat three-layer targets of Si (5 μm), Al (2 μm), and Au (0.05–0.26 μm) by radiation converted to the second harmonic from the Iskra-4 iodine laser with an intensity of 4×1013−7×1013 W/cm2 (τ
0.5∼1 ns), which acts on the Si side of the target. A method for detecting the occurrence of mixing is developed. It is established
that under the experimental conditions the thickness of the mixing region is at least ∼0.15 μm. The results of a theoretical analysis of the evolution of the disturbances leading to mixing are presented.
Zh. éksp. Teor. Fiz. 111, 882–888 (March 1997)
Deceased. 相似文献
68.
M. B. Shundalov G. A. Pitsevich A. M. Bel’skii I. P. Zyat’kov 《Journal of Applied Spectroscopy》1997,64(1):22-28
Based on the solution for the Mathieu equation, we obtained wave functions for the internal rotation of an ethane molecule
that satisfy the symmetry properties of the group G36. We calculated the frequency of the principal torsional transition (273 cm−1). The types of symmetry of the energy levels and transition probabilities in IR and Raman spectra are determined. We note
drawbacks of divisible permutable-inverse nuclear groups and the groups of molecular symmetry associated with their construction,
as well as difficulties that appear when equivalent rotations are used. The possibility of avoiding the application of an
extended group is indicated.
Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 64, No. 1, pp. 26–31, January–February, 1997. 相似文献
69.
An experimental study of transmission holographic optical elements is presented. Several important aspects related to the diffractional analysis of these elements have been considered. The case of the spherical object wave is analyzed in detail. The emphasis is on obtaining the entropy from the intensity distribution on an image plane. We use the calculated entropy to locate experimentally the position of the best image plane in the sense of minimal aberrations for a holographic lens. The comparison of experimental and theoretical results is presented and good agreement between theory and experimentation has been obtained.Part of this paper was presented at the IS & T/SPIE symposium in Electronic Imaging, Science and Technology (Practical Holography IX) February 4–10, 1995, San José, CA, USA 相似文献
70.
S. A. Bel’kov A. V. Bessarab O. A. Vinokurov V. A. Gaidash N. V. Zhidkov V. M. Izgorodin G. A. Kirillov G. G. Kochemasov A. V. Kunin D. N. Litvin V. M. Murugov L. S. Mkhitar’yan S. I. Petrov A. V. Pinegin V. T. Punin N. A. Suslov V. A. Tokarev 《JETP Letters》1998,67(3):171-175
Experiments designed to investigate the effect of a controlled large-scale asymmetry of a shell containing deuterium-tritium
fuel on the shell compression and neutron production under indirect (x-ray) action are performed on the Iskra-5 laser fusion
device. The uniformity of the x radiation near the target is not worse than 3%, and the shell asymmetry is varied from 30
to 100%. The observed decrease of the experimental neutron yield as compared with experiments using symmetric targets is in
satisfactory agreement with two-dimensional calculations.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 3, 161–165 (10 February 1998) 相似文献