22,418 research outputs found

    Project for the analysis of technology transfer Quarterly report, 13 Jul. - 12 Oct. 1968

    Get PDF
    Statistical characteristics of transfer data bank users, and outline of technology transfer and utilization instruction cours

    Theory of the cold collision frequency shift in 1S--2S spectroscopy of Bose-Einstein-condensed and non-condensed hydrogen

    Full text link
    We show that a correct formulation of the cold collision frequency shift for two photon spectroscopy of Bose-condensed and cold non-Bose-condensed hydrogen is consistent with experimental data. Our treatment includes transport and inhomogeneity into the theory of a non-condensed gas, which causes substantial changes in the cold collision frequency shift for the ordinary thermal gas, as a result of the very high frequency (3.9kHz) of transverse trap mode. For the condensed gas, we find substantial corrections arise from the inclusion of quasiparticles, whose number is very large because of the very low frequency (10.2Hz) of the longitudinal trap mode. These two effects together account for the apparent absence of a "factor of two" between the two possibilities. Our treatment considers only the Doppler-free measurements, but could be extended to Doppler-sensitive measurements. For Bose-condensed hydrogen, we predict a characteristic "foot" extending into higher detunings than can arise from the condensate alone, as a result of a correct treatment of the statistics of thermal quasiparticles.Comment: 16 page J Phys B format plus 6 postscript figure

    Project for the analysis of technology transfer Quarterly evaluation report, 13 Oct. - 12 Dec. 1968

    Get PDF
    Technical support package usage documentation by technology transfer analysis projec

    Applications of satellite technology to broadband ISDN networks

    Get PDF
    Two satellite architectures for delivering broadband integrated services digital network (B-ISDN) service are evaluated. The first is assumed integral to an existing terrestrial network, and provides complementary services such as interconnects to remote nodes as well as high-rate multicast and broadcast service. The interconnects are at a 155 Mbs rate and are shown as being met with a nonregenerative multibeam satellite having 10-1.5 degree spots. The second satellite architecture focuses on providing private B-ISDN networks as well as acting as a gateway to the public network. This is conceived as being provided by a regenerative multibeam satellite with on-board ATM (asynchronous transfer mode) processing payload. With up to 800 Mbs offered, higher satellite EIRP is required. This is accomplished with 12-0.4 degree hopping beams, covering a total of 110 dwell positions. It is estimated the space segment capital cost for architecture one would be about 190Mwhereasthesecondarchitecturewouldbeabout190M whereas the second architecture would be about 250M. The net user cost is given for a variety of scenarios, but the cost for 155 Mbs services is shown to be about $15-22/minute for 25 percent system utilization

    Invariance of the correlation energy at high density and large dimension in two-electron systems

    Full text link
    We prove that, in the large-dimension limit, the high-density correlation energy \Ec of two opposite-spin electrons confined in a DD-dimensional space and interacting {\em via} a Coulomb potential is given by \Ec \sim -1/(8D^2) for any radial confining potential V(r)V(r). This result explains the observed similarity of \Ec in a variety of two-electron systems in three-dimensional space.Comment: 4 pages, 1 figure, to appear in Phys. Rev. Let

    Disks in Expanding FRW Universes

    Get PDF
    We construct exact solutions to Einstein equations which represent relativistic disks immersed into an expanding FRW Universe. It is shown that the expansion influences dynamical characteristics of the disks such as rotational curves, surface mass density, etc. The effects of the expansion is exemplified with non-static generalizations of Kuzmin-Curzon and generalized Schwarzschild disks.Comment: Revised version to appear in ApJ, Latex, 17 pages, 10 figures, uses aaspp4 and epsf style file

    Harrison transformation of hyperelliptic solutions and charged dust disks

    Full text link
    We use a Harrison transformation on solutions to the stationary axisymmetric Einstein equations to generate solutions of the Einstein-Maxwell equations. The case of hyperelliptic solutions to the Ernst equation is studied in detail. Analytic expressions for the metric and the multipole moments are obtained. As an example we consider the transformation of a family of counter-rotating dust disks. The resulting solutions can be interpreted as disks with currents and matter with a purely azimuthal pressure or as two streams of freely moving charged particles. We discuss interesting limiting cases as the extreme limit where the charge becomes identical to the mass, and the ultrarelativistic limit where the central redshift diverges.Comment: 20 pages, 9 figure

    Health professions students' interprofessional experiences on a rural learning platform

    Get PDF
    HEALTH PROFESSIONS STUDENTS’ LEARNING EXPERIENCES ON A RURAL COLLABORATIVE LEARNING PLATFORM ABSTRACTA Faculty of Health Sciences launched a rural collaborative learning platform to cultivate interprofessional key competencies and to improve health outcomes. The purpose of the study was to describe health sciences students’ experiences of an rural collaborative learning platform. Health professions students created digital stories reflecting on their collaborative learning experiences. Purposive sampling resulted in 23 submissions. Qualitative analysis of content identified themes and categories. Three themes, namely, metaphor, critical consciousness and professional socialisation, were identified. The metaphor categories, Journey, Setting world ablaze, Water, and Puzzle, represent students’ desire to use visual cues to describe their experiences. Transformation, Personal development and Empathy signified critical consciousness. Collaborative practice, Values, Reflective practice, and Key competencies relate to professional socialisation. The researchers gained understanding of students’ experiences on an rural collaborative learning platform. Through digital stories, students became aware of professional interdependency, which linked their experiences to key interprofessional competencies.

    The X-ray Spectrum of the Rapid Burster using the Chandra HETGS

    Get PDF
    We present observations of the Rapid Burster (RB, also known as MXB 1730-335) using the Chandra High Energy Transmission Grating Spectrometer. The average interval between type II (accretion) bursts was about 40 s. There was one type I (thermonuclear flash) burst and about 20 "mini-bursts" which are probably type II bursts whose peak flux is 10-40% of the average peak flux of the other type II bursts. The time averaged spectra of the type II bursts are well fit by a blackbody with a temperature of kT = 1.6 keV, a radius of 8.9 km for a distance of 8.6 kpc, and an interstellar column density of 1.7e22 per sq. cm. No narrow emission or absorption lines were clearly detected. The 3 sigma upper limits to the equivalent widths of any features are < 10 eV in the 1.1-7.0 keV band and as small as 1.5 eV near 1.7 keV. We suggest that Comptonization destroys absorption features such as the resonance line of Fe XXVI.Comment: 10 pages, 4 figures, accepted for publication in AJ (with minor changes and enhanced discussion of the instrument configuration

    Project for the analysis of technology transfer - The initial year Annual report, 13 Nov. 1967 - 12 Nov. 1968

    Get PDF
    Program description and data analyses of transfer of NASA and AEC generated technology to secondary use
    • …
    corecore