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Full-Text Articles in Physical Sciences and Mathematics
Temperature And Variability Of Three Ionian Volcanoes, Daniel R. Allen
Temperature And Variability Of Three Ionian Volcanoes, Daniel R. Allen
Theses and Dissertations
Cassini spacecraft images of Io obtained during its flyby of Jupiter in late 2000 and early 2001 were used to determine the lava composition and eruption style of three faint hotspots, Pillan, Wayland, and Loki. We found a maximum color temperature of 1130+/-289 K for Pillan and maximum color temperatures of 1297+/-289 K and 1387+/-287 K for Wayland and Loki, respectively. These temperatures are suggestive of basaltic lava. The temperatures with the best signal-to-noise ratios also suggested basaltic lava and were found to be 780+/-189 K, 1116+/-250 K, and 1017+/-177 K for Pillan, Wayland, and Loki, respectively. Pillan showed increased …
High-Temperature Calcium Vapor Cell For Spectroscopy On The 4s2 1s0-4s4p 3p1 Intercombination Line, Christopher J. Erickson, Brian Neyenhuis, Dallin S. Durfee
High-Temperature Calcium Vapor Cell For Spectroscopy On The 4s2 1s0-4s4p 3p1 Intercombination Line, Christopher J. Erickson, Brian Neyenhuis, Dallin S. Durfee
Faculty Publications
We have demonstrated a high-temperature vapor cell for absorption spectroscopy on the Ca intercombination line. The cell uses a dual-chamber design to achieve the high temperatures necessary for an optically dense vapor while avoiding the necessity of high-temperature vacuum valves and glass-to-metal seals. We have observed over 50% absorption in a single pass through the cell. Although pressure broadening in the cell prevented us from performing saturated-absorption spectroscopy, the broadening resulted in higher signal-to-noise ratios by allowing us to probe the atoms with intensities much greater than the 0.2µW/cm2 saturation intensity of the unbroadened transition. The techniques presented in this …
Creation Of An Ultracold Neutral Plasma, Scott D. Bergeson, T. C. Killian, S. Kulin, L. A. Orozco, C. Orzel, S. L. Rolston
Creation Of An Ultracold Neutral Plasma, Scott D. Bergeson, T. C. Killian, S. Kulin, L. A. Orozco, C. Orzel, S. L. Rolston
Faculty Publications
We report the creation of an ultracold neutral plasma by photoionization of laser-cooled xenon atoms. The charge carrier density is as high as 2×10^9 cm^-3, and the temperatures of electrons and ions are as low as 100 mK and 10 uK, respectively. Plasma behavior is evident in the trapping of electrons by the positive ion cloud when the Debye screening length becomes smaller than the size of the sample. We produce plasmas with parameters such that both electrons and ions are strongly coupled.
Catalogs Of Temperatures And [Fe/H] Averages For Evolved G And K Stars, B. J. Taylor
Catalogs Of Temperatures And [Fe/H] Averages For Evolved G And K Stars, B. J. Taylor
Faculty Publications
A catalog of mean values of [Fe/H] for evolved G and K stars is described. The zero point for the catalog entries has been established by using differential analyses. Literature sources for those entries are included in the catalog. The mean values are given with rms errors and numbers of degrees of freedom, and a simple example of the use of these statistical data is given. For a number of the stars with entries in the catalog, temperatures have been determined. A separate catalog containing those data is briefly described.
Photoconductive Characterization Of Znxcd1-Xte (0≤X≤0.25) Single Crystal Alloys, David D. Allred, Elías López-Cruz, Jesus González-Hernández, Worth P. Allred
Photoconductive Characterization Of Znxcd1-Xte (0≤X≤0.25) Single Crystal Alloys, David D. Allred, Elías López-Cruz, Jesus González-Hernández, Worth P. Allred
Faculty Publications
Large grain polycrystalline and single crystals of ZnxCd1-xTe grown by a modified Bridgman method were studied using the photoluminescence and photoconductivity techniques. The temperature dependence of the band gap, as determined by photoluminescence, follows the Varshni equation for measuring temperature in the range of 15-290 K. One of the fitted parameters, the Debye temperature, monotonically decreases with the increase of the atomic zinc concentration. A close correlation between the photoluminescence and photoconductivity measurements is also found. Samples in which the photoluminescence spectra exhibit emission bands associated to cadmium vacancies and other structural defects, show a photoresponse curve which includes, in …
Superconductivity At 155 K, David D. Allred, S. R. Ovshinsky, R. T. Young, G. Demaggio, G. A. Van Der Leeden
Superconductivity At 155 K, David D. Allred, S. R. Ovshinsky, R. T. Young, G. Demaggio, G. A. Van Der Leeden
Faculty Publications
Transition to a superconducting zero-resistance state at 155 K is observed for the first time in bulk material. A new five-element compound has been synthesized with nominal composition Y1Ba2Cu3F2Oy. Fluorine plays a critical role in achieving this effect. X-ray diffraction and electron microprobe analysis indicate that the samples are multiphasic. Evidence is presented that the samples contain superconducting phases with onset temperatures considerably above 155 K. Magnetic measurements suggest a flux-trapping effect below 260 K, and diamagnetic deviations from Curie-Weiss behavior in the range from 250 K≤T≤100 K indicate that Meissner effect in a small superconducting volume fraction.
Equation Of State Of Sodium Chloride, Daniel L. Decker
Equation Of State Of Sodium Chloride, Daniel L. Decker
Faculty Publications
Because of many requests, I wish to publish the following numerical table of results for the equation of state of NaCl as calculated in an earlier paper1 along with a few comments on various proposed equations for NaCl. Table I gives the pressure in kilobars at the corresponding values of t.a/ao and temperature in the appropriate row and column. The parameter t.a/ao is the fractional compression of the lattice parameter where the standard value ao is the appropriate lattice parameter at zero pressure and 25°C. The increments between the values given in the table were chosen such that one can …