42,187 research outputs found

    New insulation attachment method eliminates compatibility bondline stresses

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    Auger-shaped single-point fastener attaches rigid surface insulation tiles to orbiter shuttle spacecraft. Method can be used to bond wide variety of materials, including insulation, elastomers, and fibrous materials. Since insulation is attached at only one point, insulation and structure are free to form without inducing bond separation

    Design, processing, and testing of LSI arrays for space station

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    Data for the beam-leaded silicon-on-sapphire (SOS) process using the TA5388 dual-complementary pair plus inverted circuit show the stability of the dc device characteristics through the complete beam-lead processing and packaging steps. A more complex circuit, the TA6567 - a silicon-gate, voltage-sense BL/CMOS/SOS 256-bit RAM, has also been made that was functionally perfect at wafer probe. Efforts to increase the yield of this circuit and to obtain electrically perfect packaged units are discussed

    Design, processing, and testing of LSI arrays for space station

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    The development of a beam-leaded low power, high performance metal-oxide-semiconductor (MOS), 256-bit random access memory (RAM) was reported. Previous success with the aluminum-gate current-sense version and a silicon-gate voltage-sense version led to the present effort to make a beam-leaded silicon-gate RAM. Some problems unique to the silicon-on-sapphire beam-lead process development are presented. Beam-leaded SOS TA5388 devices using a Si3N4 passivation layer were shown to have good electrical parameters

    The z>4 Quasar Population Observed by Chandra and XMM-Newton

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    The current status of our Chandra and XMM-Newton project on high-redshift (z>4) quasars is briefly reviewed. We report the main results obtained in the last few years for the detected quasars, along with a few (~10%) intriguing cases where no detection has been obtained with Chandra snapshot observations.Comment: 4 pages, to appear in the proceedings of 'Multiwavelength AGN surveys' (Cozumel, December 8-12 2003), ed. R. Maiolino and R. Mujic

    The challenging scales of the bird: Shuttle tile structural integrity

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    The principal design issues, tests, and analyses required to solve the tile integrity problem on the space shuttle orbiters are addressed. Proof testing of installed tiles is discussed along with an airflow test of special tiles. Orbiter windshield tiles are considered in terms of changes necessary to ensure acceptable margins of safety for flight

    Parental Functioning in Families for Behavioral Parent Training and Importance of Clinically Meaningful Change

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    Objective/Method: Statistically significant and clinically meaningful effects of behavioral parent training on parental functioning were examined for 20 children with ADHD and their parents who had successfully completed a psychosocial treatment for ADHD. Results/Conclusion: Findings suggest that behavioral parent training resulted in statistically significant improvements in some domains of parenting behavior for both mothers and fathers and in reductions in most domains of parenting stress for mothers. Importantly, clinically meaningful change also was noted for these parental functioning areas, as well as for other domains of parental functioning that did not result in statistically significant findings. Clinical implications are discussed

    Electron spin relaxation in n-type InAs quantum wires

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    We investigate the electron spin relaxation of nn-type InAs quantum wires by numerically solving the fully microscopic kinetic spin Bloch equations with the relevant scattering explicitly included. We find that the quantum-wire size and the growth direction influence the spin relaxation time by modulating the spin-orbit coupling. Due to inter-subband scattering in connection with the spin-orbit interaction, spin-relaxation in quantum wires can show different characteristics from those in bulk or quantum wells and can be effectively manipulated by various means.Comment: 8 pages, 6 figure

    Hall effect in laser ablated Co_2(Mn,Fe)Si thin films

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    Pulsed laser deposition was employed to grow thin films of the Heusler compounds Co_2MnSi and Co_2FeSi. Epitaxial growth was realized both directly on MgO (100) and on a Cr or Fe buffer layer. Structural analysis by x-ray and electron diffraction shows for both materials the ordered L2_1 structure. Bulk magnetization was determined with a SQUID magnetometer. The values agree with the Slater-Pauling rule for half-metallic Heusler compounds. On the films grown directly on the substrate measurements of the Hall effect have been performed. The normal Hall effect is nearly temperature independent and points towards a compensated Fermi surface. The anomalous contribution is found to be dominated by skew scattering. A remarkable sign change of both normal and anomalous Hall coefficients is observed on changing the valence electron count from 29 (Mn) to 30 (Fe).Comment: 9 pages, 6 figures submitted to J Phys
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