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101.
102.
103.
Mean lifetimes of levels in 22Ne have been measured by the Doppler-shift attenuation method using the inverse reaction 4He(19F, pγ)22Ne. The Doppler-broadened lineshapes observed at 0° were analyzed using scaled experimental stopping powers and give the following results for each of the following levels (energy in keV and lifetime in fs): 4457 ( < 15), 5147 (1300 ± 500), 5522 (27 ± 4), 5641 ( < 20), 6311 (70 ± 10), 6345 ( < 15), 6636 ( < 20) and 6817 ( < 15). The lifetime of the 6311 keV 6+ level is particularly interesting for testing model predictions. The large basis shell model calculations of Preedom and Wildenthal are in good agreement with the experimental B(E2) values for the 2+, 4+ and 6+ members of the ground-state band. 相似文献
104.
B. Davies 《Physics letters. A》1974,48(4):298-300
We show that the Lifshitz and related theories of intermolecular interactions are equivalent to perturbation theory, and therefore subject to the usual restrictions of the latter. 相似文献
105.
C.J. Batty S.F. Biagi M. Blecher R. Kunselman R.A.J. Riddle B.L. Roberts J.D. Davies G.J. Pyle G.T.A. Squier D.M. Asbury M. Leon 《Nuclear Physics A》1978,296(3):361-372
The attenuation due to the E2 nuclear resonance effect has been measured in hadronic atoms using pions with 111Cd and 112Cd, and for kaons with 122Sn. Energies of the relevant X-ray and γ-ray transitions and of the X-ray cascade intensities have also been measured so as to give a self-consistent set of information. The results are found to be in very good agreement with theoretical calculations. 相似文献
106.
This paper describes the design, construction and use of a field-cycled proton-electron double-resonance imaging (FC-PEDRI) system for the detection and imaging of free radicals. The unique feature of this imager is its use of a 450-mT detection magnetic field in order to achieve good image quality and sensitivity. The detection magnetic field is provided by a superconducting magnet, giving high stability and homogeneity. Field cycling is implemented by switching on and off the current in an internal, coaxial, resistive secondary magnet that partially cancels the superconducting magnet's field at the sample; the secondary magnet is actively shielded to avoid eddy currents. EPR irradiation takes place at approximately 5 mT, following which the field is switched to 450 mT in 40 ms for NMR signal detection. Full details of the imager's subsystems are given, and experiments to image the distribution of stable free radical contrast agents in phantoms and in anesthetized rats are described. 相似文献
107.
[1-14C]-E-dehydromatricaria methyl ester and dimethyl [1-14C]-deca-4,6,8-triyne-1,10-dioate are incorporated into the allene (-)-marasin in Marasmius ramealis without scrambling of the 14C label. This and the levels of the incorporations (0.8% and 4.9% respectively) strongly suggests that the above esters, or close relatives, can be converted directly into (-)-marasin in M. ramealis, and that the diyne-allene moiety in this latter compound arises by the rearrangement, under enzymic control, of an alkyltriyne moiety. 相似文献
108.
Allison IF Davies CT Gray A Kronfeld AS Mackenzie PB Simone JN;HPQCD;Fermilab Lattice;UKQCD 《Physical review letters》2005,94(17):172001
We use lattice QCD to predict the mass of the Bc meson. We use the MILC Collaboration's ensembles of lattice gauge fields, which have a quark sea with two flavors much lighter than a third. Our final result is mBc = 6304+/-12(+18)(-0) MeV. The first error bar is a sum in quadrature of statistical and systematic uncertainties, and the second is an estimate of heavy-quark discretization effects. 相似文献
109.
Beşli S Coles SJ Davies DB Hursthouse MB Ibişoglu H Kiliç A Shaw RA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(19):4915-4920
X-ray crystallographic evidence shows that nucleophilic substitution reactions of two different types of cyclophosphazene derivatives with relatively rigid nine-membered ansa rings leads to the first demonstration of retention of configuration in these molecular systems. 相似文献
110.
Davies SG Rodríguez-Solla H Tamayo JA Garner AC Smith AD 《Chemical communications (Cambridge, England)》2004,(21):2502-2503
A highly diastereoselective conjugate reduction using SmI2 and D2O has been demonstrated on a homochiral benzylidene diketopiperazine template, giving methyl (2S,3R)-N-acetyl-2-amino-2,3-dideuterio-3-phenylpropionate in 93% de and 90% ee after deprotection, hydrolysis and N-acetylation. 相似文献