Cryogenic metallic positive expulsion bellows evaluation

Cryogenic metallic positive expulsion bellows evaluatio

A study of polymers containing silicon- nitrogen bonds Annual summary report, May 4, 1965 - May 3, 1966

Polymers containing silicon-nitrogen bonds as elastomers with high thermal stability for aerospace application

A Test of Interventions to Increase Adherence to Hypertensive Medical Regimens

Low rates of adherence to hypertensive therapy limit patients' securing the full benefits of treatment. While some factors related to adherence have been identified, research on the effectiveness of interventions to increase adherence levels is sparse. The present study was designed to assess the impact of a series of different interventions on a group of some 400 patients, all under the care of private physicians in a small community. A factorial design was employed to deliver four, sequential educational interventions, about four months apart, to randomly selected sub-groups. Interviews before and after each intervention provided information concerning self-reported adherence, health status, health beliefs, and personal characteristics. Pertinent medical records and pharmacy data were also obtained. The first intervention—printed material—did not significantly affect adherence. The second and fourth interventions—nurse telephone calls and social support—each increased medication taking and the third intervention—self-monitoring—led to better weight control. There was no cumulative impact of the interventions and different aspects of regimens were not signiticantly related to one another.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67164/2/10.1177_109019818100800303.pd

Zero-energy Andreev surface bound states in the lattice model

The conditions for zero-energy Andreev surface bound states to exist are found for the lattice model of d-wave superconductor with arbitrary surface orientation. Both nearest neighbors and next nearest neighbors models are considered. It is shown that the results are very sensitive to the surface orientation. In particular, for half-filled $(hl0)$-surface zero-energy Andreev surface states only appear under the condition that $h$ and $l$ are odd simultaneouslyComment: 9 pages, 1 figur

The effect of galaxy mass ratio on merger--driven starbursts

We employ numerical simulations of galaxy mergers to explore the effect of galaxy mass ratio on merger--driven starbursts. Our numerical simulations include radiative cooling of gas, star formation, and stellar feedback to follow the interaction and merger of four disk galaxies. The galaxy models span a factor of 23 in total mass and are designed to be representative of typical galaxies in the local Universe. We find that the merger--driven star formation is a strong function of merger mass ratio, with very little, if any, induced star formation for large mass ratio mergers. We define a burst efficiency that is useful to characterize the merger--driven star formation and test that it is insensitive to uncertainties in the feedback parameterization. In accord with previous work we find that the burst efficiency depends on the structure of the primary galaxy. In particular, the presence of a massive stellar bulge stabilizes the disk and suppresses merger--driven star formation for large mass ratio mergers. Direct, co--planar merging orbits produce the largest tidal disturbance and yield that most intense burst of star formation. Contrary to naive expectations, a more compact distribution of gas or an increased gas fraction both decrease the burst efficiency. Owing to the efficient feedback model and the newer version of SPH employed here, the burst efficiencies of the mergers presented here are smaller than in previous studies.Comment: 26 pages, 21 figures, submitted to MNRA

Evidence for Surface Andreev Bound states in Cuprate Superconductors from Penetration Depth Measurements

Tunneling and theoretical studies have suggested that Andreev bound states form at certain surfaces of unconventional superconductors. Through studies of the temperature and field dependence of the in-plane magnetic penetration depth lambda_ab at low temperature, we have found strong evidence for the presence of these states in clean single crystal YBCO and BSCCO. Crystals cut to expose a [110] interface show a strong upturn in lambda_ab at around 7K, when the field is oriented so that the supercurrents flow around this surface. In YBCO this upturn is completely suppressed by a field of ~0.1 T.Comment: 4 pages 2 column revtex + 4 postscript figures. Submitted to PR

Discrete-Lattice Model for Surface Bound States and Tunneling in d-Wave Superconductors

Surface bound states in a discrete-lattice model of a $d_{x^2 - y^2}$ cuprate superconductor are shown to be, in general, coherent superpositions of an incoming excitation and more than one outgoing excitation, and a simple graphical construction based on a surface Brillouin zone is developed to describe their nature. In addition, a momentum-dependent lifetime contribution to the width of these bound states as observed in tunneling experiments is derived and elucidated in physical terms.Comment: 4 pages, 1 figure, revte

Spontaneous flux in a d-wave superconductor with time-reversal-symmetry-broken pairing state at {110} boundaries

The induction of an s-wave component in a d-wave superconductor is considered. Near the {110}-oriented edges of such a sample, the induced s-wave order parameter together with d-wave component forms a complex combination d+e^{i\phi} s, which breaks the time reversal symmetry (BTRS) of the pairing state. As a result, the spontaneous current is created. We numerically study the current distribution and the formation of the spontaneous flux induced by the current. We show that the spontaneous flux formed from a number of defect lines with {110} orientation has a measurable strength. This result may provide a unambiguous way to check the existence of BTRS pairing state at {110}-oriented boundaries.Comment: 4 pages, 2 ps-figures, content changed, references adde