573 research outputs found
Study of the Mechanisms of Flux Pinning in Type 2 Superconductors
Flux pinning mechanisms in type-2 semiconductors and specific heat measurements on annealed and deformed pure niobium sample
Cryogenic magnetometer development Final report, 1 Jul. 1964 - 7 Mar. 1967
Magnetometers for measuring stable magnetic fields produced by low field superconducting shield
“This Incredible Monster Was Always in the Way”: The Moral Career of a Sexual Sinner in the Church of Jesus Christ of Latter Day Saints
This article elaborates a symbolic interactionist approach to the scientific study of sexual sin. We draw on archival materials from The Church of Jesus Christ of Latter-day Saints (LDS), and explore recurring themes within the archival materials that signify and outline stages of a sexual sinners’ moral career. Our findings demonstrate how LDS leaders constructed a sinner’s moral career as characterized by (1) seeking out sinful temptation; (2) causing social and spiritual destruction; and (3) seeking and finding redemption. Further, we draw out implications for understanding the ways religious leaders conceptualize sexual sins for their followers, and the usefulness of conceptualizing various religious traditions, adaptations, and conceptualizations of sin as moral careers
Interfacial Electronic Charge Transfer and Density of States in Short Period Cu/Cr Multilayers
Nanometer period metallic multilayers are ideal structures to investigate electronic phenomena at interfaces between metal films since interfacial atoms comprise a large atomic fraction of the samples. The Cu/Cr binary pair is especially suited to study the interfaces in metals since these elements are mutually insoluble, thus eliminating mixing effects and compound formation and the lattice mismatch is very small. This allows the fabrication of high structural quality Cu/Cr multilayers that have a structure which can be approximated in calculations based on idealized atomic arrangements. The electronic structure of the Cu and the Cr layers in several samples of thin Cu/Cr multilayers were studied using x-ray absorption spectroscopy (XAS). Total electron yield was measured and used to study the white lines at the Cu L{sub 2} and L{sub 3} absorption edges. The white lines at the Cu absorption edges are strongly related to the unoccupied d-orbitals and are used to calculate the amount of charge transfer between the Cr and Cu atoms in interfaces. Analysis of the Cu white lines show a charge transfer of 0.026 electrons/interfacial Cu atom to the interfacial Cr atoms. In the Cu XAS spectra we also observe a van Hove singularity between the L{sub 2} and L{sub 3} absorption edges as expected from the structural analysis. The absorption spectra are compared to partial density of states obtained from a full-potential linear muffin-tin orbital calculation. The calculations support the presence of charge transfer and indicate that it is localized to the first two interfacial layers in both Cu and Cr
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Interfacial Effects in Multilayers
Interfacial structure and the atomic interactions between atoms at interfaces in multilayers or nano-laminates have significant impact on the physical properties of these materials. A technique for the experimental evaluation of interfacial structure and interfacial structure effects is presented and compared to experiment. In this paper the impact of interfacial structure on the performance of x-ray, soft x-ray and extreme ultra-violet multilayer optic structures is emphasized. The paper is concluded with summary of these results and an assessment of their implications relative to multilayer development and the study of buried interfaces in solids in general
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Mechanical Properties of Cu/Ta Multilayers Prepared by Magnetron Sputtering
The microstructure and mechanical properties of sputtered Cu/Ta multilayers were studied. X- ray diffraction and transmission electron microscopy characterization indicate that both the Ta and Cu in the 2 nm period multilayer are predominantly amorphous, while in longer period samples, the layers are crystalline, with the metastable tetragonal {beta}-Ta observed. No observable microstructure changes upon annealing at 300{degrees}C were found. An average Vickers micro- hardness value of about 5.5 GPa was measured, which increases about 5% upon annealing at 300{degrees}C. Residual stress in the multilayers and its dependence on thermal annealing are reported. The relationships between microstructure and mechanical properties in the multilayers are discussed
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Stab Sensitivity of Energetic Nanolaminates
This work details the stab ignition, small-scale safety, and energy release characteristics of bimetallic Al/Ni(V) and Al/Monel energetic nanolaminate freestanding thin films. The influence of the engineered nanostructural features of the energetic multilayers is correlated with both stab initiation and small-scale energetic materials testing results. Structural parameters of the energetic thin films found to be important include the bi-layer period, total thickness of the film, and presence or absence of aluminum coating layers. In general the most sensitive nanolaminates were those that were relatively thick, possessed fine bi-layer periods, and were not coated. Energetic nanolaminates were tested for their stab sensitivity as freestanding continuous parts and as coarse powders. The stab sensitivity of mock M55 detonators loaded with energetic nanolaminate was found to depend strongly upon both the particle size of the material and the configuration of nanolaminate material, in the detonator cup. In these instances stab ignition was observed with input energies as low as 5 mJ for a coarse powder with an average particle dimension of 400 {micro}m. Selected experiments indicate that the reacting nanolaminate can be used to ignite other energetic materials such as sol-gel nanostructured thermite, and conventional thermite that was either coated onto the multilayer substrate or pressed on it. These results demonstrate that energetic nanolaminates can be tuned to have precise and controlled ignition thresholds and can initiate other energetic materials and therefore are viable candidates as lead-free impact initiated igniters or detonators
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Nanostructure Multilayer Materials for Capacitor Energy Storage for Eh Vehicles
Acceleration and regenerative breaking for electric and hybrid vehicles require high power capacitors to complement energy sources. Large, flat nanostructure multilayer capacitors (NMCS) can provide load balancing capacitance in EHVs of the future. Additional uses include snubber capacitors for power electronics such as motor drives, energy discharge capacitors for lasers, and numerous industrial and military electronics applications [1]. In the present work, we demonstrate the effectiveness of LLNL`s multilayer materials technology by fabricating NMC test films with high energy and power density
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High Energy Density Capacitors for Power Electronic Applications Using Nano-Structure Multilayer Technology
Power electronics applications are currently limited by capacitor size and performance. Only incremental improvements are anticipated in existing capacitor technologies, while significant performance advances are required in energy density and overall performance to meet the technical needs of the applications which are important for U.S. economic competitiveness. One application, the Power Electronic Building Block (PEBB), promises a second electronics revolution in power electronic design. High energy density capacitors with excellent electrical thermal and mechanical performance represent an enabling technology in the PEBB concept. We propose a continuing program to research and develop LLNL`s nano-structure multilayer technologies for making high voltage, high energy density capacitors. Our controlled deposition techniques are capable of synthesizing extraordinarily smooth sub-micron thick layers of dielectric and conductor materials. We have demonstrated that, with this technology, high voltage capacitors with an order of magnitude improvement in energy density are achievable
Evaluating the effectiveness of message design in accelerated online programs using a think aloud protocol
This study reviews the potential implications associated with message design, timing, and delivery on students in an Accelerated Online Program. Attention to participant verbal and physical reactions will be analyzed utilizing a non-positivistic Think Aloud Protocol on a select sample. The aspects of the study will enable researchers to obtain data related to individual reflections
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