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Notes: Co/Ru hcp (0001) superlattices were grown by UHV evaporation onto mica substrates. We demonstrate the growth of epitaxially ordered Co/Ru superlattices–despite the large lattice mismatch ((approximately-equal-to)8%)–consisting of hcp (0001) Co and Ru sublayers initialized on 150-A(ring)-thick single-crystalline Ru buffer layer by using RHEED and x-ray diffraction. The magnetic properties were studied by magnetization and ferromagnetic resonance (FMR) measurements. For uncoupled Co layers, the resultant anisotropy switch from planar to axial direction (perpendicular to the film plane) with decreasing Co sublayers thickness. For Co sublayer thickness smaller than a critical one tco(approximately-equal-to)14 A(ring), the magnetization is directed perpendicular to the film plane. For small Ru interlayer thickness, large antiferromagnetic exchange coupling between the Co sublayers is observed in agreement with precious results. For a certain range of Co and Ru thicknesses, superlattices with unique magnetic parameters are obtained. Indeed, in the absence of an applied field, the magnetization is oriented along the film normal while the adjacent Co layers are coupled antiferromagnetically. For this magnetic structure, the magnetization process exhibits a hysteresis and the FMR spectra an irreversible behavior when the applied field is along the film normal.As shown by SQUID measurements, when the field is decreased from a quasi-saturated state, the layers are essentially coupled ferromagnetically, the antiferromagnetic state appearing following a spin-flip process (staircaselike on the magnetization curve) for a field smaller than a critical one. However, with increasing field, the antiferromagnetic state disappears by progressive steps suggesting that the spin reorientation process occurs by coherent rotation of the magnetization combined with spin-flip process. The occurrence of this effect is particularly spectacular on the FMR spectra. With decreasing field, a classical FMR absorption is observed due to the basical ferromagnetic state while with increasing field, this absorption is largely reduced or disappears completely due to the antiferromagnetic one. The magnitude of the hysteresis and its evolution with the direction of the applied field, the values of the critical field corresponding to the spin flip and to the field above which the magnetic state is reversible, are very well correlated on the FMR spectra and the magnetization curves.

Notes: We have developed an experimental method for investigating the interaction between two dc track edges by studying the track edge noise. We conclude that two edges do not interact when they are several micrometers apart, but the noise reduces nearly to zero when their separation is less than about half a micrometer. There is a transition region that exists between these two limits. The net track edge noise power from two dc edges is quantized, implying that in our experiment track edges interact around the complete revolution of the disk or not at all.

Notes: Track edge fluctuations on recording media affect signal-to-noise ratio and servo control, and can provide clues to the medium's magnetic microstructure. We write track edges on longitudinal thin-film magnetic recording media by dc erasing the medium and writing a saturated dc track of opposite magnetization direction on the erased band. We then "read'' the position fluctuations of the x-component reversal of one edge of the written track by centering a head on that edge, and by stepping the head across the edge. Since a straight track edge would not produce any flux change in the read head coil, the voltage output of the head arises from flux changes due to track edge fluctuations. The spectrum of the fluctuations can be deduced by decorrelating the read head sensitivity function from the voltage spectrum. We have used this procedure with several low- and high-noise thin-film media and we find in each case a k−b spectrum (k=wave number) with b near 1. We propose a model which interprets the fluctuations as a superposition of uncorrelated protuberances from a nominal straight edge, and we deduce the size distribution of the protuberances which will generate the observed fluctuation spectrum. Simulated reconstruction of the track edge resulting from a weighted superposition of the protuberances permits semiquantitative inferences to be drawn from the model about the medium microstructure.

Notes: The pseudospectral (PS) method for self-consistent-field calculations is extended for use in generalized valence-bond calculations and is used to calculate singlet–triplet excitation energies in methylene, silylene, and ethylene molecules and bond dissociation and twisting energies in ethylene. We find that the PS calculations lead to an accuracy in total energies of ≤0.1 kcal/mol and excitation energies to ≤0.01 kcal/mol for all systems. With effective core potentials on Si, we find greatly improved accuracy for PS.

Notes: A definitive demonstration of inhomogeneous vibrational line broadening in a liquid is made from Raman echo measurements of the sym-methyl stretching vibration of CH3I in a 50% mixture with CDCl3. The lifetime of the inhomogeneity is found to be 4–7 ps. The source of the inhomogeneity is identified as concentration fluctuations within the first solvation shell. The range and time scale of the interaction are consistent with the predictions of Schweizer and Chandler [J. Chem. Phys. 76, 2296 (1982)] for an attractive force interaction.

Notes: Presented in this paper are the description and the test results of a new stationary thermometry system used to map the temperature of the outer surface of 1.5 GHz superconducting single-cell cavities during operation at 1.6 K. The system comprises 764 removable carbon thermometers whose signals are multiplexed and scanned by a Macintosh computer. A complete temperature map can be obtained in as little as 0.1 s at a temperature resolution of about 0.2 mK. Alternatively, it has been demonstrated that if the acquisition time is increased to several seconds, then a temperature resolution on the order of 30 μK is possible. To our knowledge, these are the fastest acquisition times so far achieved with L-band cavities at these resolutions.

Notes: This study identified population groups, health conditions, and employment settings considered appropriate for graduate-level community health nursing (CHN) practice and employment, and described the relative importance of each of these areas as assessed by CHN leaders. According to 588 leaders in CHN service and education, (1) the population groups most in need of graduate-prepared CHNs are the elderly, persons of low socioeconomic status, the homeless, adolescents, and the unemployed; and (2) the health conditions most in need of CHN services are AIDS, pregnancy and prenatal problems, low birth weight and infant mortality, stress-related illness, and Alzheimer's and other chronic diseases of the elderly. Among the many employment settings rated as having a great need for CHNs are state and local health departments and home health agencies. The findings provide the direction and justification for developing specialty options within CHN that correspond to these identified and changing needs. This article provides suggestions and possible alternatives for initiating educational change to prepare graduate-level CHNs for these various specialties and for the settings in which the specialties will be applied.

Notes: This study identified core components of the curriculum for master's-level community health nurses (CHNs) and assessed whether leaders in service agreed with leaders in education on the importance of these components. Through a mailed survey, 588 leaders in CHN service and education identified the following as the most important to include in the core CHN curriculum: a practicum experience; epidemiology; community health assessment and diagnosis; administration and management, including public health administration, management theory, program planning and evaluation, financial management and budgeting, and quality assurance; research methods and biostatistics; health promotion and disease prevention; intervention at the aggregate level; and leadership theory. These leaders also indicated that skills in both administration and direct care are essential for CHN