ABSTRACT
The second harmonic (SH) generation from the highly epitaxial Al-doped ZnO film on sapphire was measured, using the femtosecond Ti:Sapphire laser at the near-resonant SH wavelength, in reflection geometry to avoid the sapphire's contribution in the conventional Maker fringes technique. By investigating SH intensities as a function of the azimuthal angle along the film's normal, we found that the sapphire substrate had a negligible contribution to the reflective SH signal and the film had a pure and well-aligned c-domain. We also developed a new method to calculate the component's ratios of the nonlinear susceptibility tensor by analyzing the polarization diagrams of SH intensities under the incidence with two different angles. The ratios indicate that Kleinman's symmetry is broken due to the absorption at SH wavelength and the dominant component of the nonlinear susceptibility tensor is d(33). Calibration using the Z-cut quartz shows a possible overestimate of the nonlinear response by Maker fringes technique.
ABSTRACT
The critical behavior of thin FeCo films grown on MgO has been studied using phase-sensitive synchrotron x-ray diffraction. These studies unravel several novel features of criticality in thin films, as the simultaneous appearance of the 3D-2D crossover and the truncation of the correlation length normal to the film at approximately 1/3 of the film thickness. Above the critical temperature of the film we observe a pronounced pinning of the order parameter at the MgO-FeCo interface, which indicates a novel critical adsorption behavior.
ABSTRACT
The order-disorder transition in a 170 A thick Cu3Au(111) epitaxial alloy film is examined using x-ray diffraction techniques. Below the transition temperature T0, a disordered surface layer of thickness l is detected. This layer exhibits wetting behavior, i.e., l increases, obeying a logarithmic growth law on approach to T0. We show by a detailed analysis of the order parameter profiles that the stiffness of the order-disorder interface is temperature dependent, resulting in a nonuniversality of the wetting transition.
ABSTRACT
This paper discusses the social condition of the childless elderly on Sikaiana, a small-scale Polynesian community in the Solomon Islands. This discussion includes a broader examination of Sikaiana expectations and understandings about kinship, parenting, aging, and caring. High rates of fosterage, diffuse kinship obligations and membership in patrilineages provide the networks of relationships that determine care for the elderly. Moreover, Sikaiana is a relatively undifferentiated and personal community making it possible for the elderly, both with and without children, to remain cared for and involved in community activities. Future research should examine how care for the elderly in this and other small-scale communities is affected by increased participation in emigration, formal education, cash economy, and occupational specialization.
ABSTRACT
Concerning the depth of sleep the duration of the maximum effect depends on the speed of injection of midazolam (0.15 mg/kg body weight). In contrast to an injection period of 15 s, midazolam produced additional stages of sleep after 90 min when given within 60 s.
