Cu Nuclear Quadrupole Resonance Study of Site-Disorder and Chemical Pressure Effects on Y(Ba1-xSrx)2Cu4O8

We report a zero-field Cu nuclear quadrupole resonance (NQR) study on the effects of nonmagnetic Sr substitution for high-Tc superconductors, Y(Ba1-xSrx)2Cu4O8 (Tc=82-80 K for x=0-0.4), using a spin-echo technique. The site-disordering and chemical pressure effects associated with doping Sr were observed in the broadened, shifted Cu NQR spectra. Nevertheless, the site disorder did not significantly affect the homogeneity of Cu electron spin dynamics, in contrast to the in-plane impurity. The peak shift of Cu NQR spectrum due to Sr was different between the chain- and the plane-Cu sites, more remarkably than those under a hydrostatic physical pressure, suggesting anisotropic or nonuniform local structural strains. The small decrease of Tc due to Sr can be traced back to either a cancellation effect on Tc between the disorder and the pressure, or an anisotropic or nonuniform chemical pressure effect on Tc.Comment: 4 pages, 5 figure

Traumatic middle cerebral artery aneurysm: case report and review of the literature

The original publication is available at www.springerlink.comArticleNEUROSURGICAL REVIEW. 30(3): 263-267 (2007)journal articl

The Decay of a Tz = -1/2 Mirror Nucleus 57Cu

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A Nuclear Structure Study of Doubly Odd Nuclei 154Tb and 156Ho

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Coexistence of α+α+n+n and α+t+t cluster structures in 10Be

The coexistence of the α+α+n+n and α+t+t cluster structures in the excited states of 10Be has been discussed. In the previous analysis, all the low-lying states of 10Be were found to be well described by the motion of the two valence neutrons around two α clusters. However, the α+t+t cluster structure was found to coexist with the α+α+n+n structure around Ex=15 MeV, close to the corresponding threshold. We have introduced a microscopic model to solve the coupling effect between these two configurations. The K=0 and K=1 states are generated from the α+t+t configurations due to the spin coupling of two triton clusters. The present case of 10Be is one of the few examples in which completely different configurations of triton-type (α+t+t three-center) and α-type (α+α+n+n two-center) clusters coexist in a single nucleus in the same energy region

Reduction of the Neutron-Induced r-Ray Background in an ISOL Experiment by Making Use of a Beam Chopper

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