374,199 research outputs found

    Spartan Daily, October 19, 1934

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    Volume 23, Issue 21https://scholarworks.sjsu.edu/spartandaily/2200/thumbnail.jp

    The Crescent Student Newspaper, October 23, 1998

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    Student Newspaper of George Fox University.https://digitalcommons.georgefox.edu/the_crescent/2200/thumbnail.jp

    The Crescent Student Newspaper, October 23, 1998

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    Student Newspaper of George Fox University.https://digitalcommons.georgefox.edu/the_crescent/2200/thumbnail.jp

    New molecular candidates: X(1910), X(2200), and X(2350)

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    Assuming the newly observed resonant structures X(1910), X(2200), and X(2350) as ωω\omega\omega, ωϕ\omega\phi, and ϕϕ\phi\phi molecular states respectively, we compute their mass values in the framework of QCD sum rules. The numerical results are 1.97±0.17GeV1.97\pm0.17 {GeV} for ωω\omega\omega state, 2.07±0.21GeV2.07\pm0.21 {GeV} for ωϕ\omega\phi state, and 2.18±0.29GeV2.18\pm0.29 {GeV} for ϕϕ\phi\phi state, which coincide with the experimental values of X(1910), X(2200), and X(2350), respectively. This supports the statement that X(1910), X(2200), and X(2350) could be ωω\omega\omega, ωϕ\omega\phi, and ϕϕ\phi\phi molecular candidates respectively.Comment: 9 pages, 9 eps figures; the name of X(2000) changed to X(1910) according to the updated data of experiments; more references and discussions added; accepted for publication in PRD. arXiv admin note: substantial text overlap with arXiv:1211.2277, arXiv:1201.341

    High-temperature strength of refractory-metal wires and consideration for composite applications

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    Tensile and stress-rupture tests were conducted on wires of W-Hf-C, W-Re-Hf-C, ASTAR 811C (a tantalum alloy), and B-88 (a columbium alloy) at room temperature, 1093 C (2000 F), and 1204 C (2200 F). Metallographic examinations were also made of the wire microstructure after testing. Ultimate tensile strength values up to 2170 meganewtons per square meter (314000 psi) at 1093 C (2000 F) and 1940 meganewtons per square meter (281 000 psi) at 1204 C (2200 F) were obtained for W-Re-Hf-C wire. The best strength values obtained for a 100-hour rupture life were, 1410 meganewtons per square meter (205 000 psi) at 1093 C (2000 F) and 910 meganewtons per square meter (132 000 psi) at 1240 C (2200 F) for W-Re-Hf-C wire. The properties obtained suggested that the wires studied showed promise as potential fiber reinforcement in the 1093 to 1204 C (2000 to 2200 F) temperature range

    ASCA and contemporaneous ground-based observations of the BL Lacertae objects 1749+096 and 2200+420 (BL Lac)

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    We present ASCA observations of the radio-selected BL Lacertae objects 1749+096 (z=0.32) and 2200+420 (BL Lac, z=0.069) performed in 1995 Sept and Nov, respectively. The ASCA spectra of both sources can be described as a first approximation by a power law with photon index Gamma ~ 2. This is flatter than for most X-ray-selected BL Lacs observed with ASCA, in agreement with the predictions of current blazar unification models. While 1749+096 exhibits tentative evidence for spectral flattening at low energies, a concave continuum is detected for 2200+420: the steep low-energy component is consistent the high-energy tail of the synchrotron emission responsible for the longer wavelengths, while the harder tail at higher energies is the onset of the Compton component. The spectral energy distributions from radio to gamma-rays are consistent with synchrotron-self Compton emission from a single homogeneous region shortward of the IR/optical wavelengths, with a second component in the radio domain related to a more extended emission region. For 2200+420, comparing the 1995 Nov state with the optical/GeV flare of 1997 July, we find that models requiring inverse Compton scattering of external photons provide a viable mechanism for the production of the highest (GeV) energies during the flare. An increase of the external radiation density and of the power injected in the jet can reproduce the flat gamma-ray continuum observed in 1997 July. A directly testable prediction of this model is that the line luminosity in 2200+420 should vary shortly after (~1 month) a non-thermal synchrotron flare.Comment: 28 pages,6 figures, 5 tables; LaTeX document. accepted for publication in the Astrophysical Journa

    EDUC 2200

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    The detection of a broad interstellar extinction feature near 1700 A

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    A statistical examination of 126 extinction curves has revealed the presence of a second broad absorption feature similar in nature to the 2200 A feature. The feature is centered on wavelength 1706 A, has a full half-width of 350 A, and a mean central height of 0.21 magnitudes. The strength of the feature increases with E(B-V) supporting an interstellar origin, and on average it is 18 times weaker than the 2200 A feature
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