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排序方式: 共有316条查询结果,搜索用时 15 毫秒
41.
L. A. Hamel L. Lessard H. Jeremie J. Chauvin 《Zeitschrift für Physik A Hadrons and Nuclei》1985,321(3):439-441
The beta decay rate of the16N(0?; 120keV) →16O(0+, G.S.) transition has been remeasured. Our result (Λ β =0.48±0.024 s?1) is in excellent agreement with a previous measurement but strongly disagrees with another experimental value. The two agreeing results provide an experimental verification of the importance of meson exchange currents in 0+-0? weak transitions. A value ofg p/g A~11–12 can be inferred from the correspondingΛ μ rate. 相似文献
42.
43.
Jean-Francois Le Borgne 《Journal of organometallic chemistry》1976,122(2):129-137
The condensation of metallated aldimines, prepared from activated lithium dialkylamides, with different dihalogenoalkenes gives aldehydes with a halogenovinylic group. Acidic hydrolysis of these aldehydes leads directly to cyclopentenones. When treated with an excess of activated amide, halogenovinylic aldimines give γ-acetylenic aldehydes. 相似文献
44.
A. Champagne G. Beaudoin L. A. Hamel H. Jeremie L. Lessard 《Zeitschrift für Physik A Hadrons and Nuclei》1988,330(4):377-385
We have measured the beta spectrum of the 0?(120 keV,t 1/2=5.25 μs) state of16N. The response function of our detector has been measured, parameterized and then fitted to known spectral shapes taken under conditions close to those in the actual experiment. Using this response function and subtracting a 56 μs half-life background due to neutron capture in the detector, the measured 0? spectrum compares well with the allowed shape for the 0?→0+ spectrum plus a small contribution from the allowed 0?→1? transition. 相似文献
45.
A. L. S. Angelis J. Antos M. Beaulieu H. Beker G. Briskin J. Bystricky M. -G. Catanesi P. Cerello S. Dagan G. Dellacasa M. Diehl S. Di Liberto B. Dolgoshein M. Esten C. W. Fabjan A. Gaidot M. Gallio P. Giubellino U. Goerlach C. Guerra L. -A. Hamel S. Konovalov I. Kralik G. London F. Martelli J. -P. Martin M. Masera M. -A. Mazzoni F. Meddi M. -T. Muciaccia S. Muraviev A. Nomerotsky Y. Oren J. -P. Pansart G. Poulard L. Ramello L. Riccati G. Rosa L. Sandor M. Sarris E. Scomparin A. Shmeleva S. Simone S. Smirnov P. Taras J. Urban E. Vercellin 《The European Physical Journal C - Particles and Fields》1998,5(1):63-75
Results are presented on and production in p–W and S–W interactions at 200 GeV/c/nucleon measured via the dimuon decay in a large kinematic region. The data are normalized to
the charged particle multiplicity in the same rapidity interval. They have been collected using the HELIOS/3 muon spectrometer
at the CERN SPS. The ratio , where is the relevant resonance branching fraction, increases between proton and sulphur projectiles, and is somewhat enhanced going from peripheral to central
S–W interactions. This results from an increase in the number of produced 's per charged particle. The ratio is measured in different intervals of p and rapidity. It is not clearly dependent on p, but is larger at higher rapidities. production, likewise normalized to charged multiplicity, is significantly lower in S–W compared to p–W interactions.
Received: 27 October 1997 / Revised version: 5 March 1998 / Published online: 13 July 1998 相似文献
46.
Howard Alper Nathalie Hamel James B. Woell David J.H. Smith 《Tetrahedron letters》1985,26(19):2273-2274
Esters are isolated in fine yields from the rhodium(I) catalyzed reaction of benzyl chlorides with borate esters and carbon monoxide, in the presence of potassium iodide. 相似文献
47.
Yang DQ Rochette JF Sacher E 《Langmuir : the ACS journal of surfaces and colloids》2005,21(18):8539-8545
The chemical and morphological modifications of multiwalled carbon nanotubes (MWCNTs), by 2 keV Ar(+) treatment, have been followed by field emission scanning (FESEM) and high-resolution transmission (HRTEM) electron microscopies and by X-ray photoelectron (XPS) and Raman spectroscopies. Morphological changes were followed, both in situ and on subsequent air exposure, and the data indicate that free radical defects, initially produced under low Ar(+) treatment doses ( approximately 10(13) ions/cm(2)), act as the nuclei for the formation of localized asperities that form along the walls of the CNTs. Continued treatment results in their stublike elongation that continues with further treatment, forming extensions under heavy treatment doses. The chemical changes that occur, on reaction with air, reveal that the defects initially created are secondary C atoms, formed when a single bond breaks; further treatment breaks an additional bond to form primary C atoms; free radical fragments, lost when the third bond breaks, condense on the free radical defects to form the asperities. The extent of primary and secondary C atoms, and thus their functionalization on air exposure, may be controlled by the extent of treatment, offering a method for the controlled surface functionalization of CNTs by low-energy Ar(+) treatment. 相似文献
48.
49.
Natalia Zaitseva Leslie Carman Andrew Glenn Jason Newby Michelle Faust Sebastien Hamel Nerine Cherepy Stephen Payne 《Journal of Crystal Growth》2011,314(1):163-170
Single crystals of a pure hydrocarbon, 1,3,5-triphenylbenzene, with properties suitable for high-energy neutron detection were grown from toluene solutions using slow evaporation and temperature reduction methods with growth rates up to 10 mm/day. Application of the rapid growth technique developed earlier for growth of large water-soluble crystals shows that crystals of aromatic compounds can be successfully grown from solutions in large volumes required for their use as scintillator materials for radiation detection. 相似文献
50.
For a smooth geometrically integral algebraic variety X over a field k of characteristic 0, we define the extended Picard complex . It is a complex of length 2 which combines the Picard group and the group , where is a fixed algebraic closure of k and . For a connected linear k-group G we compute the complex (up to a quasi-isomorphism) in terms of the algebraic fundamental group . We obtain similar results for a homogeneous space X of a connected k-group G. To cite this article: M. Borovoi, J. van Hamel, C. R. Acad. Sci. Paris, Ser. I 342 (2006). 相似文献