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971.
Francesco De Vincentiis Giorgio Bencivenni Dr. Fabio Pesciaioli Andrea Mazzanti Dr. Giuseppe Bartoli Prof. Patrizia Galzerano Dr. Paolo Melchiorre Prof. Dr. 《化学:亚洲杂志》2010,5(7):1652-1656
The first catalytic method for the asymmetric aziridination of cyclic enones is described. The presented organocatalytic strategy is based on the use of an easily available organocatalyst that is able to convert a wide range of cyclic enones into the desired aziridines with very high enantiomeric purity and good chemical yield. Such a method may very well open up new opportunities to stereoselectively prepare complex chiral molecules that possess an indane moiety, a framework that is found in a large number of bioactive and pharmaceutically important molecules 相似文献
972.
We developed a constituent quark-diquark model for the nucleon and its resonances using a harmonic oscillator potential for
the interaction. The effects due to relativistic kinetic energy correction are studied. Finally, charge form factor of the
model is calculated and compared with experimental data.
相似文献
973.
A. De Roeck A. Katre P. Mermod D. Milstead T. Sloan 《The European Physical Journal C - Particles and Fields》2012,72(4):1985
The experiments at the Large Hadron Collider (LHC) are able to discover or set limits on the production of exotic particles
with TeV-scale masses possessing values of electric and/or magnetic charge such that they behave as highly ionising particles
(HIPs). In this paper the sensitivity of the LHC experiments to HIP production is discussed in detail. It is shown that a
number of different detection methods are required to investigate as fully as possible the charge-mass range. These include
direct detection as the HIPs pass through either passive or active detectors and, in the case of magnetically charged objects,
the so-called induction method with which magnetic monopoles which stop in accelerator and detector material could be observed.
The benefit of using complementary approaches to HIP detection is discussed. 相似文献
974.
Darwin P. R. Kint Antxon Martínez De Ilarduya Sebastin Muoz‐Guerra 《Journal of Polymer Science.Polymer Physics》2001,39(13):1553-1564
The microstructure and crystallization behavior of a set of poly(ethylene terephthalate‐co‐5‐nitroisophthalate) copolymers (PETNI) containing 5‐nitroisophthalic units in the 10–50 mol % range were examined and compared to those of poly(ethylene terephthalate) (PET) and poly(ethylene terephthalate‐co‐isophthalate) (PETI) copolymers. A 13C NMR analysis of PETNI copolymers in a trifluoroacetic acid solution indicates that they are random copolymers with average sequence lengths in accordance with ideal polycondensation statistics. Differential scanning calorimetry (DSC) studies show that PETNI containing 5‐nitroisophthalic units up to 20 mol % are able to crystallize and that crystallization takes place in these copolymers at much slower rates than in PET. Wide‐angle X‐ray diffraction from powder and fibers reveals that crystallizable PETNI adopts the same triclinic crystal structure as PET, with the nitroisophthalate units being excluded from crystallites. Fourier transform infrared in combination with cross‐polarization/magic‐angle spinning 13C NMR spectroscopy demonstrates the occurrence of a gauche–trans conversion encompassing the crystallization process. A correlation between DSC and spectroscopic data leads us to conclude that the content of trans conformer in the noncrystallized phase of PETNI is higher than in both PET and PETI copolymers and suggests that secondary crystallization in the homopolymer must proceed by a mechanism different than that in copolymers. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1553–1564, 2001 相似文献
975.
976.
G. Spavieri V. Guerra R. De Abreu G. T. Gillies 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(3):457-463
Propagation of Aharonov-Bohm matter waves and light waves in moving media is
characterized by the interaction electromagnetic momentum. Thus, recent
models of light propagation in moving rarefied media justify and call for an optical experiment of the Mascart-Jamin type,
capable of testing the
modern interpretations of ether drift experiments. 相似文献
977.
H. E. Roman A. Celi G. De Filippi 《The European physical journal. Special topics》2008,161(1):195-205
We study long-term behaviour of air temperature, wave heights and wind speed time
series recorded for the period 1993–1997 at a meteo-marine station located in the
Adriatic Sea. The scaling analysis shows that fluctuations of air temperature
display long-range autocorrelations, while those for wave heights show a more complex
behaviour, crossing over from a persistent regime at intermediate time scales (up
to about 20 days) to an anti-persistence behaviour at longer times. Furthermore,
the crosscorrelations of their records are found to be large, with a covariance
of about -0.3 (indicating anti-crosscorrelations) within the full 5-years period,
giving a quantitative measure of the actual coupling between the two data sets. Wind
speed fluctuations are found to be strongly crosscorrelated (about 0.6) with those
of wave heights, indicating as expected that wind is the main driving force for wave
height fluctuations. 相似文献
978.
Francesca De Mori 《Czechoslovak Journal of Physics》2002,52(5):735-735
Table of Contents
Contents of the Supplement B to Vol. 52 (2002) 相似文献979.
S. S. De 《International Journal of Theoretical Physics》2002,41(7):1291-1305
From a consideration of extended hadron structure in the microlocal anisotropic space-time, the mesonic and baryonic states with their internal quantum numbers such as strangeness, hypercharge, baryon number are constructed. The SU
3 baryonic multiplets of baryons with spin (j +
) are generated from the SU
3 mesonic multiplets of mesons with spin j. The meson–baryon mass differences are also derived here. The composite particle field of hadrons for the macroscopic space-time are obtained. In particular, the meson field and one particle meson state are considered here. These one particle hadron states of the macroscopic space-time also possess the quantum numbers (strangeness, hypercharge, etc.) which are regarded as the manifestations of the anisotropic nature of the microlocal space-time. The composite fields constructed here are usable in the reduction formulae of the S-matrix approach for strong interaction. 相似文献
980.
Oxidizing species in the mechanism of cytochrome P450 总被引:2,自引:0,他引:2
This review discusses the mechanisms of oxygen activation by cytochrome P450 enzymes, the possible catalytic roles of the various iron--oxygen species formed in the catalytic cycle, and progress in understanding the mechanisms of hydrocarbon hydroxylation, heteroatom oxidation, and olefin epoxidation. The focus of the review is on recent results, but earlier work is discussed as appropriate. The literature through to February 2002 is surveyed, and 175 referenced are cited. 相似文献