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21.
D. Pierroutsakou A. Boiano A. De Rosa M. Di Pietro G. Inglima M. La Commara Ruhan Ming B. Martin R. Mordente A. Ordine F. Rizzo V. Roca M. Romoli M. Sandoli F. Soramel L. Stroe M. Trotta E. Vardaci 《The European Physical Journal A - Hadrons and Nuclei》2003,17(1):71-76
The 32S + 100Mo and 36S + 96Mo fusionlike reactions were studied at incident energy of E
lab = 298 MeV and 320 MeV, respectively, with the aim of probing the influence of the entrance channel charge asymmetry on the
dipole γ-ray emission. The excitation energy and spin distribution of the compound nucleus created in these reactions were
identical, the only difference being associated with the unequal charge asymmetry of the two entrance channels. High-energy
γ-rays were detected in an array of 9 seven-pack BaF2 clusters. Coincidence with fusionlike residues detected in four PPAC ensured the selection of central reaction events. By
studying the differential γ-ray multiplicity associated with the two reactions it was shown that the dipole strength excited
in the compound nucleus increases with the entrance channel charge asymmetry. From the linearized spectra, the increase of
the GDR γ-ray intensity was found to be ∼ 25% for the more charge asymmetric system. The results are discussed and compared
with those of previous data obtained at different incident energies.
Received: 21 October 2002 / Accepted: 23 December 2002 / Published online: 1 April 2003 相似文献
22.
Thermal conductivity measurements using the flash method 总被引:1,自引:0,他引:1
Gaal P. S. Thermitus M.-A. Stroe Daniela E. 《Journal of Thermal Analysis and Calorimetry》2004,78(1):185-189
Thermal diffusivity is the speed with which heat propagates through a material. It has a multitude of direct applications,
such as determining heat transfer through brake pads at the moment of contact, etc., but more often it is used to derive thermal
conductivity from the fundamental relationship tying it with specific heat capacity and density. Using a new multi-sample
configuration system, and testing a reference sample adjacent to the unknown, specific heat capacity can be obtained parallel
with thermal diffusivity. Thus, a single test yields thermal diffusivity and thermal conductivity with prior knowledge of
density. The method is fast and produces results with high accuracy and very good repeatability. The sample size, 12 to 30
mm diameter and 2 to 5 mm thickness, is easy to handle and is well suited for a broad range of materials, even for composites,
often a problem for other methods. Typical data on two polymers, Pyrex glass and Pyroceram 9606 are presented.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
23.
C. Pantea I. Stroe J.B. Betts L.L. Daemen A. Migliori 《Journal of Physics and Chemistry of Solids》2008,69(1):211-213
Osmium's Debye characteristic temperature ΘD remains uncertain. We tabulate 20 reported values that average 411±94 K, for a property that one should know within about 1%. We report a new value derived from low-temperature monocrystal elastic-constant measurements extrapolated to 0 K: ΘD=477±2 K. Our value disagrees with all previous reports except one specific-heat measurement. It agrees with Mendeleev-table expectations and with an a priori calculation. 相似文献
24.
A. Andrighetto O. Bajeat A. E. Barzakh S. Essabaa D. V. Fedorov A. M. Ionan V. S. Ivanov R. Leroy G. Lhersonneau K. A. Mezilev F. V. Moroz S. Yu. Orlov V. N. Panteleev L. Stroe L. B. Tecchio A. Villari Yu. M. Volkov X. F. Wang 《The European Physical Journal A - Hadrons and Nuclei》2005,23(2):257-264
A series of on-line mass separation experiments have been performed at the IRIS facility to measure the yield and release of Rb and Cs neutron-rich isotopes produced by fission reaction of 238U. A 1 GeV proton beam was used to bombard uranium carbide targets with the densities of 11 g/cm3 and 1.5 g/cm3 held at temperatures in the range (2000-2230) °C. The release curves of Rb and Cs long-lived isotopes were measured from both kinds of targets. The overall production efficiency was determined making use of experimentally measured cross-sections of that isotope production. Comparison of the experimental yields of Rb and Cs isotopes with the calculated ones after corrections for losses due to finite release times suggests that the diffusion is the dominating process reducing the efficiency for short-lived isotopes. When normalized to the same thickness, an enhancement for the high-density rod target of the measured isotope yields is observed when going far from stability. This is possibly explained by the reactions induced by secondary neutrons. A significant odd-even effect with higher yields of Cs even neutron isotopes has been observed, confirming a similar effect obtained in earlier experiments. 相似文献