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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
provided by the
Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 281 to 290 of 1616 (0.022 seconds)Spelling suggestions: "subject:"ways"" "subject:"days""
| 281 |
Effects of x-ray radiation on survival of the cereal leaf beetle, oulema melanopus (L.) /Carey, Walter Emmitt January 1968 (has links)
No description available.
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| 282 |
Directional correlation of gamma rays in Germanium-72 /Monahan, Wayne Gordon January 1968 (has links)
No description available.
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| 283 |
A silicon diode mosaic array vidicon tube for x-ray imaging /Jacoby, Benjamin Franklin January 1969 (has links)
No description available.
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| 284 |
The effects of acute gamma radiation on chrysanthemum inflorescence morphogenesis/Naskali, Richard John January 1969 (has links)
No description available.
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| 285 |
The analysis and development of instrumentation for a position sensitive semiconductor gamma ray camera /Gerber, Mark Stanley January 1975 (has links)
No description available.
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| 286 |
An on-axis Fresnel zone plate imaging system with a germanium gamma ray camera and computer reconstruction /Kelly, Kevin A. January 1976 (has links)
No description available.
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| 287 |
An energy dispersive X-ray diffraction study of vitreous silica /Meek, Thomas Thornton January 1977 (has links)
No description available.
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| 288 |
Evaluation of a four-element beta gamma personnel dosimetry badgeTietze, Lorrie R. January 1985 (has links)
Call number: LD2668 .T4 1985 T53 / Master of Science
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| 289 |
The evolution of active galactic nuclei in clusters of galaxies from the Dark Energy SurveyBufanda, E., Hollowood, D., Jeltema, T. E., Rykoff, E. S., Rozo, E., Martini, P., Abbott, T. M. C., Abdalla, F. B., Allam, S., Banerji, M., Benoit-Lévy, A., Bertin, E., Brooks, D., Carnero Rosell, A., Carrasco Kind, M., Carretero, J., Cunha, C. E., da Costa, L. N., Desai, S., Diehl, H. T., Dietrich, J. P., Evrard, A. E., Fausti Neto, A., Flaugher, B., Frieman, J., Gerdes, D. W., Goldstein, D. A., Gruen, D., Gruendl, R. A., Gutierrez, G., Honscheid, K., James, D. J., Kuehn, K., Kuropatkin, N., Lima, M., Maia, M. A. G., Marshall, J. L., Melchior, P., Miquel, R., Mohr, J. J., Ogando, R., Plazas, A. A., Romer, A. K., Rooney, P., Sanchez, E., Santiago, B., Scarpine, V., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Tarle, G., Thomas, D., Tucker, D. L., Walker, A. R. 01 March 2017 (has links)
The correlation between active galactic nuclei (AGNs) and environment provides important clues to AGN fuelling and the relationship of black hole growth to galaxy evolution. In this paper, we analyse the fraction of galaxies in clusters hosting AGN as a function of redshift and cluster richness for X-ray-detected AGN associated with clusters of galaxies in Dark Energy Survey (DES) Science Verification data. The present sample includes 33 AGNs with LX > 1043 erg s(-1) in non-central, host galaxies with luminosity greater than 0.5L(*) from a total sample of 432 clusters in the redshift range of 0.1< z <0.95. Analysis of the present sample reveals that the AGN fraction in red-sequence cluster members has a strong positive correlation with redshift such that the AGN fraction increases by a factor of similar to 8 from low to high redshift, and the fraction of cluster galaxies hosting AGN at high redshifts is greater than the low-redshift fraction at 3.6 sigma. In particular, the AGN fraction increases steeply at the highest redshifts in our sample at z > 0.7. This result is in good agreement with previous work and parallels the increase in star formation in cluster galaxies over the same redshift range. However, the AGN fraction in clusters is observed to have no significant correlation with cluster mass. Future analyses with DES Year 1 through Year 3 data will be able to clarify whether AGN activity is correlated to cluster mass and will tightly constrain the relationship between cluster AGN populations and redshift.
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| 290 |
MODEL ATMOSPHERES FOR X-RAY BURSTING NEUTRON STARSMedin, Zach, Steinkirch, Marina von, Calder, Alan C., Fontes, Christopher J., Fryer, Chris L., Hungerford, Aimee L. 21 November 2016 (has links)
The hydrogen and helium accreted by X-ray bursting neutron stars is periodically consumed in runaway thermonuclear reactions that cause the entire surface to glow brightly in X-rays for a few seconds. With models of the emission, the mass and radius of the neutron star can be inferred from the observations. By simultaneously probing neutron star masses and radii, X-ray bursts (XRBs) are one of the strongest diagnostics of the nature of matter at extremely high densities. Accurate determinations of these parameters are difficult, however, due to the highly non-ideal nature of the atmospheres where XRBs occur. Observations from X-ray telescopes such as RXTE and NuStar can potentially place strong constraints on nuclear matter once uncertainties in atmosphere models have been reduced. Here we discuss current progress on modeling atmospheres of X-ray bursting neutron stars and some of the challenges still to be overcome.
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