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101.
Th. Ackermann 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》1969,81(10):405-405
102.
103.
P. Heitjans B. Bader H. -J. Stöckmann K. Dörr G. Kiese H. Ackermann P. Freiländer W. Müller-Warmuth K. Meise-Gresch 《Hyperfine Interactions》1983,16(1-4):597-600
Nuclear spin-lattice relaxation in Li20·2Si02 glass below 200 K has been studied using the asymmetric Β-decay radiation of polarized8Li (T1/2=0.Bs) nuclei produced by capture of polarized neutrons. Transients of the8Li polarization follow an exp(?√E/T1) law. The dependence of the spin-lattice relaxation rate ⊥¯1 1 on temperature T and magnetic field B can roughly be described by T¯1 1~T/B. The interpretation is based on the assumption that for8Li, contrary to7Li in the same glass, spin-diffusion is absent and that each probe nucleus is coupled by quadrupolar interaction to an individual distribution of nearby centres typical of glasses. The fluctuation of these centres causing relaxation may be induced by either a multi-phonon or a thermally activated motional process. 相似文献
104.
105.
106.
The theory of hopping-impurity-conduction developed byConwell andMott, Pollak etc. is extended by thermodynamic viewpoints. It is shown that the model which is providing simple and independend electron transitions from one donator to another is not adequate except at very low temperatures (<4 °K) and high frequencies (1010 Hz). At lower frequencies coupled transitions must be considered. This transportmechanism is described by a Boltzmann-equation. 相似文献
107.
108.
F.?P.?He?bergerEmail author S.?Hofmann I.?Kojouharov D.?Ackermann 《The European Physical Journal A - Hadrons and Nuclei》2004,22(2):253-260
Isomeric states in 210-215Ra have been populated by the decay of the compound nuclei 216,220Ra produced in irradiations of 204,208Pb with 12C at
MeV. Published values for
-ray energies and half-lives were confirmed for
Ra. Our data for
Ra agree with the
-energies and the half-life measured at the RITU separator, University of Jyväskylä (Finland). Its decay pattern is complex. Two series of
-rays of
keV and
keV were observed. A half-life of
s was measured. The isomeric state is attributed to an 8 + state at E
* = 2053.8keV. A previously unknown isomeric state was assigned to
Ra. It has a half-life of (
)
and it decays by emission of
-rays with energies of 396.1keV and 802.0keV. It is attributed to a 13/2 + state at E
* = 1198.1 keV.PACS:
23.60. + e
decay - 27.90. + b
相似文献
109.
Femtosecond three-pulse photon-echo studies of acetic acid dimers in solution reveal multilevel coherence of O-H stretching excitations caused by the anharmonic coupling between the high-frequency stretching and low-frequency hydrogen-bond motions. We demonstrate for the first time that such multilevel coherence determines the nonexponential decay of the macroscopic O-H stretching polarization, whereas spectral diffusion processes play a minor role. The dephasing time of individual vibrational transitions contributing to the overall polarization is approximately 200 fs. 相似文献
110.
A. N. Andreyev D. Ackermann F. P. Heßberger S. Hofmann M. Huyse I. Kojouharov B. Kindler B. Lommel G. Münzenberg R. D. Page K. Van de Vel P. Van Duppen K. Heyde 《The European Physical Journal A - Hadrons and Nuclei》2003,18(1):55-64
Alpha-decay of the new nuclide 184Bi has been studied in the complete-fusion reaction 93Nb(94Mo, 3n)184Bi at the velocity filter SHIP. The evaporation residues were separated in-flight and subsequently identified on the basis of recoil-
, recoil-
-
analysis and excitation functions measurements. Two
-decaying isomeric states in 184Bi with half-life values of 13(2) ms and 6.6(1.5) ms were identified. The
-branching ratio of 180Tl was deduced for the first time as
. Improved data on the fine-structure
-decay of 186Bi were obtained in the 93Nb(95Mo, 2n)186Bi reaction. A similarity of the decay energies and half-life values of 184,186Bi is pointed out and a possible explanation for this effect is suggested.Received: 14 March 2003, Revised: 29 April 2003, Published online: 2 September 2003PACS:
23.60.+e
decay - 27.70.+q
- 27.80.+w
K. Heyde: Present address: EP-ISOLDE, CERN, CH-1211, Geneva 23, Switzerland. 相似文献