Browsing Physics by Date of Publication
Now showing items 81-100 of 2116
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Performance and preliminary calibration of the Hopkins ultraviolet telescope on the Astro-2 mission
(American Astronomical Society, 1995)An improved version of the Hopkins Ultraviolet Telescope (HUT) made its second flight on the Astro-2 mission aboard the Space Shuttle Endeavour from 1995 March 2--18. The longer mission duration and greatly improved pointing ... -
Electron localization in mixed-valence manganites
(American Physical Society, 1995)Mixed-valence manganites (A3+0.7B2+0.3)MnO3 exhibit a resistivity peak with giant negative magnetoresistance below the Curie point. Residual resistivity ranges from 5?10-8 to 8?103 m, but the electronic heat capacity when ... -
New rigid backbone conjugated organic polymers with large fluorescence quantum yields
(1995)The effect on optical emission of the presence of carbon?carbon triple bond linkages in conjugated aromatic copolymers is studied and leads to fluorescence quantum yields of up to 50%, substantially higher than most ... -
Phase-matched gratings for enhanced forward degenerate four-wave mixing
(1995)A phase-matched grating to enhance the second-order diffracted signals generated by forward degenerate four-wave mixing has been proposed and demonstrated for the first time to the authors' knowledge. Experiments have been ... -
Spin-dependent photoconductivity in CVD- and MBE-grown silicon-on-sapphire
(1995)Spin-dependent photoconductivity is observed in (100) silicon films grown on sapphire by CVD and MBE. The CVD films are either in their as-grown state or have undergone single or double solid-phase epitaxial regrowth. For ... -
Effect of static electric field on luminescence spectra of quantum-size CdS, PbI2 particles and CdS monocrystals
(1995)The influence of static electric field on the luminescence spectra of quantum confined CdS and Pbl2 particles as well as bulk CdS monocrystals has been studied in this work. The applied electric field causes the increase ... -
The Type IC supernova 1994I in M51: detection of helium and spectral evolution
(American Astronomical Society, 1995)We present a series of spectra of SN 1994I in M51, starting 1 week prior to maximum brightness. The nebular phase began about 2 months after the explosion; together with the rapid decline of the optical light, this ... -
The far-ultraviolet spectrum of NGC 4151 as observed with the Hopkins ultraviolet telescope on Astro-2
(American Astronomical Society, 1995)We observed NGC 4151 on six separate occasions at intervals of 1 to 3 days using the Hopkins Ultraviolet Telescope during the flight of Astro-2 aboard the space shuttle Endeavour in 1995 March. The far-UV spectra cover the ... -
Growth of free and trapped exciton luminescence of quantum - size CdS nanocrystals under combined UV laser irradiation and static electric field action
(Belarusian State University of Informatics and Radioelectronics, 1995) -
Luminescence spectra of quantum size CdS and PbI2 particles in static electric field
(Acta Physica Polonica A, 1995) -
Steps toward determination of the size and structure of the broad-line region in active galatic nuclei. 8: an intensive HST, IUE, and ground-based study of NGC 5548
(1995)We present the data and initial results from a combined Hubble Space Telescope (HST)/IUE/ground-based spectroscopic monitoring campaign on the Seyfert 1 galaxy NGC 5548 that was undertaken in order to address questions ... -
Electron paramagnetic resonance of erbium doped silicon
(American Institute of Physcis, 1996)Electron paramagnetic resonance measurements have been made on samples of float zone silicon, implanted with 1015 Er/cm2. One sample was coimplanted with oxygen to give an impurity concentration of 1020 O/cm3 and 1019 ... -
Far-ultraviolet spectra of broad absorption line QSOs and constraints on models for the ionization structure and metallicity of the BAL-region gas
(American Astronomical Society, 1996)Hubble Space Telescope Faint Object Spectrograph G270H spectra of four moderate-to high-redshift broad absorption line (BAL) QSOs are presented. In addition, evidence is discussed that indicates that the gas that gives ... -
Optically pumped ZnCdSe-ZnSe quantum wells
(1996)We have measured the gain spectrum of an optically pumped 40A ZnCdSe-ZnSe multiple quantum well. Our calculation, which includes many body effects such as Coulomb enhancement and spectral broadening due to carrier ... -
Far-ultraviolet observations of NGC 3516 using the Hopkins ultraviolet telescope
(American Astronomical Society, 1996)We observed the Seyfert 1 galaxy NGC 3516 twice during the flight of Astro-2 using the Hopkins Ultraviolet Telescope aboard the Space Shuttle Endeavour in March 1995. Simultaneous X-ray observations were performed with the ... -
Vacancies, interstitials and close Frenkel Pairs on the zinc sublattice of ZnSe
(American Physical Society, 1996)Zinc vacancies (VZn), zinc interstitials (Zni), and ~25 distinct VZn?Zni Frenkel pairs of different lattice separations are observed in ZnSe by the optical detection of magnetic resonance in photoluminescence after 2.5 MeV ... -
ASCA observations of the composite warm absorber in NGC 3516
(American Astronomical Society, 1996)We obtained X-ray spectra of the Seyfert 1 galaxy NGC 3516 in 1995 March using the Japanese X-ray satellite, ASCA. Simultaneous far-UV observations were obtained with the Hopkins Ultraviolet Telescope on the Astro-2 shuttle ... -
Spin scattering in ferromagnetic thin films
(American Physical Society, 1996)By combining parallel and transverse magnetoresistance measurements on thin films of Co and Ni, the contribution of spin scattering at the domain walls is separated from the anisotropic magnetoresistance (AMR). A model, ... -
Study of shear force as a distance regulation mechanism for scanning near-field optical microscopy
(American Institute of Physics, 1996)Results of the investigation into the suitability of the shear?force distance regulation mechanism for scanning near?field optical microscopy (SNOM) are presented. It is shown that there is a range of relative sizes of ... -
Hubble space telescope observations of the gravitationally lensed cloverleaf broad absorption line QSO H1413+1143: imaging
(American Astronomical Society, 1996)An analysis of Hubble Space Telescope (HST) Wide Field Planetary Camera (WFPC) and Wide Field Planetary Camera 2 (WFPC2) images of the gravitationally lensed Cloverleaf broad absorption line quasi-stellar object (QSO) ...