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51.
It is shown that associated with any sufficiently sharp resonance there is a delayed emergence of particles that under suitable conditions follows an exponential law of decay to an excellent approximation over many lifetimes. The dependence of the duration of the exponential curve on the resonance width, on the excitation width, and on the observation distance, is examined in detail. 相似文献
52.
53.
54.
D. Ward G.D. Dracoulis J.R. Leigh R.J. Charity D.J. Hinde J.O. Newton 《Nuclear Physics A》1983,406(3):591-612
Levels to spin 16+ in the ground band and 17? in the octupole band in 222Th have been identified using the reaction 208Pb(18O, 4n)222Th at 93 MeV. To suppress intense γ-ray background from fission a residue detector was built and operated in coincidence with the Ge(Li) and NaI(Tl) detectors. The apparent moment of inertia in the ground-state rotational band rises very rapidly with increasing spin, however, no indications of backbending were observed. The octupole band at low spin has an aligned angular momentum relative to the ground-state band. Strong cross-band E1 transitions competed with collective E2 transitions within each band. Analysis showed that the ratios were within experimental uncertainty independent of both the spin and parity of the parent state.The average γ-ray multiplicity per cascade was measured for 222Th. The results were in reasonable agreement with the computer code ORNL-ALICE. 相似文献
55.
D. P. Barber J. B. Dainton L. C. Y. Lee R. Marshall J. C. Thompson D. T. Williams T. J. Brodbeck G. Frost G. N. Patrick G. F. Pearce D. Newton T. Sloan G. R. Brookes W. J. Haynes P. B. Wilkes LAMP Group 《Zeitschrift fur Physik C Particles and Fields》1984,26(3):343-351
The differential and total corss sections and the decay density matrix elements have been measured for the reactions, γp→ωp and γp→ωΔ+ (1232) in the photon energy range 2.8 to 4.8 GeV. The total cross sections for ωΔ+ (1232) photo-production are found to be slightly larger than those for elastic ω photo-production in this energy range. The data are compared to the predictions of a theoretical model and the contributing exchange mechanics are discussed. 相似文献
56.
The authors follow up some previous work on the dynamics of pension funding by three notes. The first of these concerns contribution rates consisting of the normal cost plus a generalized amortization method for unfunded supplemental present value (actuarial accrued liability). The second note examines aggregate cost funding for active members when there exist consistent difference between the assumed and the actual rates of interest and of growth. The third note explores the operation of a variable annuity system in the context of our general model for pension funding dynamics. 相似文献
57.
The paper develops a theory of electron transfer with torsionally induced non-Condon (NC) effects. The starting point of the theory is a generalized spin-boson Hamiltonian, where an additional torsional oscillator bilinearly coupled to other bath modes causes a sinusoidal NC modulation. We derive closed form time dependent nonadiabatic rate expressions for both sudden and relaxed initial conditions, which are applicable for general spectral densities and energetic condition. Under the assumption that the torsional motion is not correlated with the polaronic shift of the bath, simple stationary limit rate expression is obtained. Model calculations of this rate expression illustrate the effects of torsional quantization and gating on the driving force and temperature dependences of the electron transfer rate. The classical limit of the rate expression consists of three Marcus-type terms, and is shown to agree very well with the exact numerical result. 相似文献
58.
Shirtcliffe NJ McHale G Newton MI Perry CC Roach P 《Chemical communications (Cambridge, England)》2005,(25):3135-3137
Switching between superhydrophobicity and superhydrophilicity in porous materials was predicted theoretically and demonstrated experimentally with the example of thermally induced contact angle change; tunability of this system was also demonstrated. 相似文献
59.
Iglesias-Juez A Martínez-Arias A Newton MA Fiddy SG Fernández-García M 《Chemical communications (Cambridge, England)》2005,(32):4092-4094
The redox behaviour of Pd-based TWCs is studied under dynamic, cycling conditions (e.g. lambda oscillations) on a 50 millisecond scale. Pd temporal response to gas inlet mixture changes is governed by metal-promoter interface properties. 相似文献
60.
P.A. Butler I.Y. Lee J.O. Newton Y. El-Masri M.M. Aleonard P. Colombani R.M. Diamond F.S. Stephens R.W. Lougheed E.K. Hulet 《Physics letters. [Part B]》1977,68(2):122-124
Excitation functions and angular distributions have been measured for the fission of 232Th, 238U, 244Pu and 248Cm induced by 86Kr and 136Xe ions at energies in the vicinity of the Coulomb barrier. No large differences as a function of either target or projectile were found. These results suggest that the main process occuring is not Coulomb fission. 相似文献