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Comparisons of VUU (Vlasov-Uehling-Uhlenbeck) predictions with streamer chamber data

Description: Experimental charged particle inclusive and exclusive parameters for several nuclear systems are compared with microscopic model predictions based on the Vlasov-Uehling-Uhlenbeck equation, for various density-dependent nuclear equations of state (EOS). Inclusive variables and multiplicity distributions are in good agreement, and are not sensitive to the EOS. Rapidity spectra show evidence of being useful in determining whether the model uses the correct sections for binary collisions in the nuclear medium, and whether momentum dependent interactions are correctly incorporated. Sideward flow parameters do not favor the same nuclear incompressibility at all multiplicities, and there are indications that the present model may provide only an upper limit on the true stiffness of the EOS. Findings relating to impact parameter averaging and the mass and energy dependence of transverse flow are also presented. 24 refs., 6 figs., 1 tab.
Date: January 1, 1987
Creator: Keane, D.; Chu, S.Y.; Fung, S.Y.; Liu, Y.M.; Qiao, L.J.; VanDalen, G. et al.
Partner: UNT Libraries Government Documents Department

Radiation damage in YBa/sub 2/Cu/sub 3/O/sub 7/ by fast neutrons

Description: The superconducting transition temperature of sintered YBa/sub 2/Cu/sub 3/O/sub 7/ decreases at a rate of 2.7 K/10/sup 18/ n/cm/sup 2/ (E > 0.1 MeV) for fast neutron irradiation. The critical current density J/sub c/ increases a factor of three at zero field and more than three at nonzero fields for fluences up to 2 x 10/sup 18/ n/cm/sup 2/. At both 7 and 75 K, J/sub c/ is decreasing with fluence near 3 x 10/sup 18/ n/cm/sup 2/.
Date: January 1, 1987
Creator: Willis, J.O.; Cost, J.R.; Brown, R.D.; Thompson, J.D. & Peterson, D.E.
Partner: UNT Libraries Government Documents Department

Resistivity of EuBa/sub 2/(Cu/sub 1-y/Zn/sub y/)/sub 3/O/sub x/ as a function of temperature, magnetic field, pressure and Zn concentration

Description: We report electrical resistance and magnetoresistance measurements on EuBa/sub 2/(Cu/sub 1-y/Zn/sub y/)/sub 3/O/sub x/ under pressure to 17 kbar. With Zn substitution, T/sub c/ is depressed rapidly (approx.19 K/at.% Zn) and there are qualitative changes in the temperature and field response of the resistance. Pressure drives the Zn-substituted samples toward undoped EuBa/sub 2/Cu/sub 3/O/sub x/ behavior. Analysis of the temperature dependent resistance for y = 0.05 and P = O, together with Hall effect and thermopower data, suggests that the suppression of superconductivity may arise from weak three-dimensional localization promoted by Coulomb interactions.
Date: January 1, 1987
Creator: Borges, H.A.; Wells, G.L.; Cheong, S.W.; Kwok, R.S.; Thompson, J.D.; Fisk, Z. et al.
Partner: UNT Libraries Government Documents Department

Experiments on heavy electron and high T/sub c/ oxide superconductors. [Gd-doped (U,Th)Be/sub 13/; RBa/sub 2/Cu/sub 3/O/sub 7/]

Description: In the first part of this paper, we briefly describe some of our efforts to determine the type of pairing and pairing mechanisms that are associated with the superconductivity of heavy electron materials by means of H/sub c2/(T) measurements in Gd-doped (U/sub 1-x/Th/sub x/)Be/sub 13/ alloys. An account of some of our recent work on the new high T/sub c/ copper oxide superconductors is given in the second part of the paper. 30 refs., 12 figs.
Date: January 1, 1987
Creator: Maple, M.B.; Dalichaouch, Y.; Ferreira, J.M.; Hake, R.R.; Lambert, S.E.; Lee, B.W. et al.
Partner: UNT Libraries Government Documents Department