We report measurements on high-T c YBa 2 Cu 3 O 7Ϫy ͑YBCO͒ Josephson ramp-edge junctions with different ab-plane orientation electrodes relatively rotated by 45°. The ramp-edge junctions with different crystal angles against the interface boundary are fabricated on an MgO͑100͒ substrate using a CeO 2 seed-layer technique. The Shapiro steps under microwave irradiation of 9 GHz appear qualitatively different for different crystal angles, which supports the d-wave nature of a YBCO superconductor. The magnetic-field dependence of the Josephson maximum current shows a Fraunhofer-like pattern, which is consistent with the calculated result for the d-wave junctions. The temperature dependencies of the maximum Josephson current for different angle geometry fall off rapidly with increasing temperature and deviate much from the conventional s-wave Ambegaokar-Baratoff prediction. The results are in good qualitative agreement with the calculated results based on the d-wave pairing symmetry taking the presence of the zero energy state into account. The observed angle dependencies clearly indicate that the angle-dependent Josephson current really exists.

A new tracking detector, scintillating track image camera (SCITIC) was used for hyperon-scattering experiments. Since the hyperon lifetimes are short, the low-energy hyperon-nucleon scattering can be studied only with a track detector used as an active target. The present experiment has shown that the SCITIC is a promising detector for the hyperon scattering experiments. Polarized hyperons AE þ were produced through pð þ ; K þ ÞAE þ reactions with a 1.6 GeV/c pion beam on a liquid scintillator of the active target. Three sets of SCITIC were used to record the pictures of AE þ production and scattering. A kaon spectrometer was used to trigger the SCITIC with a signal of kaon from the reaction. Left/right asymmetries of the AE þ p scattering were determined through analyses of the pictorial data, and the results were in accordance with a quark-model prediction that the asymmetry was large in the AE þ p scattering while it was small in the ÃN case.

The differential incoherent scattering cross sections of 320 kev photons by K-shell electrons of lead, tantalum and samarium are experimentally determined employing a fast-slow coincidence scintillation spectrometer by the degraded photon Kx-ray coincidence technique at angles of scattering 45", 60", 90" and 110'. T h e results are compared with the computed values and the trends of the incoherent scattering function are discussed.

Using photoluminescence (PL) and deep-level transient spectroscopy (DLTS) we observed the concentration changes of Curelated centers in silicon crystals saturated with Cu at various temperatures (600 -1000 C), in which each sample was measured at the same location for both methods. The DLTS peak assigned to have the same origin as the 1.014 eV PL center (Cu PL center) was by far the strongest component among the DLTS peaks, and no DLTS peak due to isolated substitutional Cu (Cu s ) was observed for any of the diffusion temperatures used. The PL and DLTS intensities of the Cu PL center increased with increasing diffusion temperature of Cu from 600 to 700 C, reached a maximum between 700 and 800 C, then sharply decreased at higher temperatures than 800 C. This behavior was reasonably explained by considering the outdiffusion and precipitation of Cu in addition to the solubility of Cu. The maximum DLTS concentration of the Cu PL center ($10 14 cm À3 ) observed in the present study far exceeded the estimated concentration of Cu s formed through a vacancy-mediated reaction. From this finding we concluded that a model containing Cu s was invalid for the Cu PL center and that another model containing unique Cu atom at the center of the Si-Si bond was realistic.

Non-relativistic Compton profiles (in the impulse approximation) have been calculated for the He, Li, Be, B and Ne atoms from the numerical wavefunctions generated by four local density models for exchange correlation. Two of the models were simple P ' '~ schemes (p is the electron charge density): Xa,'l (the common form of the X a approximation) and X x / 2 ( X a with a stepfunction radial dependence for a). The other two, due to Hedin and Lundqvist and to Ng, contain p-dependent terms beyond the X r approximation which are intended to represent correlation corrections in approximate fashion. Except for Xrll with a = 4, the models all yield J,(O) (the Compton profile peak) within 2 % of one another.Both X a j l ( z~~) and Hedin-Lundqvist J,(O) values are always larger (by 1-5 %) than those generated from correlated wavefunctions, and the profiles produced from those models in general do not differ by more than about one per cent. The J,(O) values from Ng's model exhibit no obvious regularity in their relation to the correlated wavefunction results. Compared with correlated wavefunction q = 0 values. (ie J~"de'(0)/J~'"(O)), Xr/l(r.,) gives the smallest standard deviation over the five atoms tested: the same is true relative to q = 0 values from Hartree-Fock wavefunctions.