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Design of volumetric sub-THz negative refractive index metamaterial with gainKantemur, A., Tang, Q., Xin, H. 06 1900 (has links)
Conventional passive metamaterials always suffer from the limitation of loss and dispersion due to fundamental causality issue. Especially it becomes severe due to material loss at terahertz frequency. Our work resolves the loss problem by introducing gain device into the metamaterial structure. A passive volumetric metamaterial is firstly designed on the quartz substrate. A negative resistance is inserted into the wire of the structure to provide the gain. We have identified resonant tunneling diodes that work up into THz frequency and shown in simulation that simultaneous negative index and gain can be obtained.
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Discovery of 16 New z ∼ 5.5 Quasars: Filling in the Redshift Gap of Quasar Color SelectionYang, Jinyi, Fan, Xiaohui, Wu, Xue-Bing, Wang, Feige, Bian, Fuyan, Yang, Qian, McGreer, Ian D., Yi, Weimin, Jiang, Linhua, Green, Richard, Yue, Minghao, Wang, Shu, Li, Zefeng, Ding, Jiani, Dye, Simon, Lawrence, Andy 30 March 2017 (has links)
We present initial results from the first systematic survey of luminous z similar to 5.5 quasars. Quasars at z similar to 5.5, the post-reionization epoch, are crucial tools to explore the evolution of intergalactic medium, quasar evolution, and the early super-massive black hole growth. However, it has been very challenging to select quasars at redshifts 5.3 <= z <= 5.7 using conventional color selections, due to their similar optical colors to late-type stars, especially M dwarfs, resulting in a glaring redshift gap in quasar redshift distributions. We develop a new selection technique for z similar to 5.5 quasars based on optical, near-IR, and mid-IR photometric data from Sloan Digital Sky Survey (SDSS), UKIRT InfraRed Deep Sky Surveys-Large Area Survey (ULAS), VISTA Hemisphere Survey (VHS), and Wide Field Infrared Survey Explorer. From our pilot observations in the SDSS-ULAS/VHS area, we have discovered 15 new quasars at 5.3. z. 5.7 and 6 new lower redshift quasars, with SDSS z band magnitude brighter than 20.5. Including other two z similar to 5.5 quasars already published in our previous work, we now construct a uniform quasar sample at 5.3 <= z <= 5.7, with 17 quasars in a similar to 4800 square degree survey area. For further application in a larger survey area, we apply our selection pipeline to do a test selection by using the new wide field J-band photometric data from a preliminary version of the UKIRT Hemisphere Survey (UHS). We successfully discover the first UHS selected z similar to 5.5 quasar.
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Academic Procrastination: Prevalence Among High School and Undergraduate Students and Relationship to Academic AchievementJanssen, Jill 15 May 2015 (has links)
This dissertation presents a literature review on procrastination and more specifically research involving the domain of academic procrastination, characteristics/traits academic procrastinators exhibit, and two different types of academic procrastinators. Even though a comprehensive theory has not been established, social cognitive theory, attribution theory, and motivation theories contribute to our understanding of academic procrastination. Studies that investigate prevalence of high school and college students who procrastinate in international settings, and more specifically in the United States, are reviewed, along with the literature on the relationship between academic procrastination and achievement. Research has demonstrated with relative consistency that academic procrastination has significant adverse effects on academic progress (Ferrari et al., 2005; Moon & Illingworth, 2005) and that high percentages of undergraduate college students self-report they engage in academic procrastination (Steel, 2007).
The literature review is followed by an investigation that utilizes an adapted version of the Procrastination Assessment Scale-Students (Özer & Ferrari, 2011), a self-report instrument, to measure students’ academic procrastination. The purpose of this study was to investigate (a) the percentage of undergraduate college and high school students who self-report academic procrastination; (b) the frequency of academic procrastination among undergraduate college and high school students for the specific academic tasks of studying for exams, completing reading assignments, and writing papers; and (c) the relationship between academic procrastination and achievement of undergraduate college and high school students. Both on specific tasks and overall, significantly more college students report higher procrastination than high school students. Unexpectedly, this study did not find a significant relationship between academic procrastination and academic achievement, as measured by grade point average. This study highlights the importance of considering students’ age when examining academic procrastination.
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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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Alma Observations of Massive Molecular Gas Filaments Encasing Radio Bubbles in the Phoenix ClusterRussell, H. R., McDonald, M., McNamara, B. R., Fabian, A. C., Nulsen, P. E. J., Bayliss, M. B., Benson, B. A., Brodwin, M., Carlstrom, J. E., Edge, A. C., Hlavacek-Larrondo, J., Marrone, D. P., Reichardt, C. L., Vieira, J. D. 14 February 2017 (has links)
We report new ALMA observations of the CO(3-2) line emission from the 2.1 +/- 0.3*10(10)M(circle dot). molecular gas reservoir in the central galaxy of the Phoenix cluster. The cold molecular gas is fueling a vigorous starburst at a rate of 500-800M(circle dot)yr(-1) and powerful black hole activity in the forms of both intense quasar radiation and radio jets. The radio jets have inflated huge bubbles filled with relativistic plasma into the hot, X-ray atmospheres surrounding the host galaxy. The ALMA observations show that extended filaments of molecular gas, each 10-20 kpc long with a mass of several billion solar masses, are located along the peripheries of the radio bubbles. The smooth velocity gradients and narrow line widths along each filament reveal massive, ordered molecular gas flows around each bubble, which are inconsistent with gravitational free-fall. The molecular clouds have been lifted directly by the radio bubbles, or formed via thermal instabilities induced in low-entropy gas lifted in the updraft of the bubbles. These new data provide compelling evidence for close coupling between the radio bubbles and the cold gas, which is essential to explain the self-regulation of feedback. The very feedback mechanism that heats hot atmospheres and suppresses star formation may also paradoxically stimulate production of the cold gas required to sustain feedback in massive galaxies.
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VLA AND ALMA IMAGING OF INTENSE GALAXY-WIDE STAR FORMATION IN z ∼ 2 GALAXIESRujopakarn, W., Dunlop, J. S., Rieke, G. H., Ivison, R. J., Cibinel, A., Nyland, K., Jagannathan, P., Silverman, J. D., Alexander, D. M., Biggs, A. D., Bhatnagar, S., Ballantyne, D. R., Dickinson, M., Elbaz, D., Geach, J. E., Hayward, C. C., Kirkpatrick, A., McLure, R. J., Michałowski, M. J., Miller, N. A., Narayanan, D., Owen, F. N., Pannella, M., Papovich, C., Pope, A., Rau, U., Robertson, B. E., Scott, D., Swinbank, A. M., Werf, P. van der, Kampen, E. van, Weiner, B. J., Windhorst, R. A. 01 December 2016 (has links)
We present; 0 4 resolution extinction-independent distributions of star formation and dust in 11 star-forming galaxies (SFGs) at z. =. 1.3-3.0. These galaxies are selected from sensitive blank-field surveys of the 2 x 2' Hubble Ultra-Deep Field at gimel = 5 cm and 1.3 mm using the Karl G. Jansky Very Large Array and Atacama Large Millimeter/submillimeter Array. They have star formation rates (SFRs), stellar masses, and dust properties representative of massive main-sequence SFGs at z similar to 2. Morphological classification performed on spatially resolved stellar mass maps indicates a mixture of disk and morphologically disturbed systems; half of the sample harbor X-ray active galactic nuclei (AGNs), thereby representing a diversity of z similar to 2 SFGs undergoing vigorous mass assembly. We find that their intense star formation most frequently occurs at the location of stellar-mass concentration and extends over an area comparable to their stellar-mass distribution, with a median diameter of 4.2 similar to 1.8 kpc. This provides direct evidence of galaxy-wide star formation in distant blank-field-selected main-sequence SFGs. The typical galactic-average SFR surface density is 2.5Me circle dot yr(-1) kpc(-2), sufficiently high to drive outflows. In X-ray-selected AGN where radio emission is enhanced over the level associated with star formation, the radio excess pinpoints the AGNs, which are found to be cospatial with star formation. The median extinctionindependent size of main-sequence SFGs is two times larger than those of bright submillimeter galaxies, whose SFRs are 3-8 times larger, providing a constraint on the characteristic SFR (similar to 300Me yr(-1)) above which a significant population of more compact SFGs appears to emerge.
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Electrochromic Polymer Devices: Active-Matrix Displays and Switchable PolarizersAndersson, Peter January 2006 (has links)
Major efforts have been spent during recent years in worldwide attempts to achieve an electronic paper technology; the common name for novel flexible displays utilizing substrates such as paper, plastics or thin metal sheets. Various kinds of technology are available that potentially will be used for an electronic paper, which differs from each other mainly with respect to the choice of active materials, substrates and manufacturing techniques. There are many applications for electronic paper technology, ranging from high-resolution displays used in electronic books to updateable large-area billboards. The latter suggests a novel electronic display function that could extend the utilization of cellulose-based paper, which is one of the most common materials ever produced by mankind, by using the paper as a thin and flexible carrier. The requirement for fast update speed in such large area applications would probably be a bit more relaxed compared to traditional display technologies, while low-power consumption and bi-stability are among the factors that should be further emphasized, together with the utilization of well-established printing techniques to enable low-cost manufacturing of the displays. The choice of active materials is therefore crucial in order to reach these objectives in reality and this paves the way for printable conjugated polymers with electrochromic properties. Chemical synthesis of these materials during the last decades has resulted in a vast variety of electrochromic polymers with custom-tailored functionality covering a broad range of optical absorption and electrical conductivities. This thesis review the studies done on the electrochemical switching of poly(3,4-ethylenedioxythiophene) (PEDOT). For this material both the electrical conductivity and the optical absorption is controlled by the oxidation state. Active matrix addressed displays that are printed on flexible substrates have been obtained by arranging electrochemical smart pixels, based on the combination of electrochemical transistors and electrochromic display cells, into cross-point matrices. The resulting polymer-based active-matrix displays are operated at low voltages and the same active material can be used in electrochemical transistors and conducting lines and in electrochromic display cells employing the electronic and the opto-electonic properties of the material, respectively. In addition to this, a switchable optical polarizer is briefly discussed. This is a device utilizing electrochromism of stretch-aligned polyaniline (PANI). The combination of two identical devices in a vertical architecture, orthogonally oriented with respect to each other, results in a filter in which the orientation of the polarized optical absorption is governed by the voltage polarity applied to the device. / Report code: LiU-TEK-LIC- 2006:18
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Manufacture and final tests of the LSST monolithic primary/tertiary mirrorMartin, H. M., Angel, J. R. P., Angeli, G. Z., Burge, J. H., Gressler, W., Kim, D. W., Kingsley, J. S., Law, K., Liang, M., Neill, D., Sebag, J., Strittmatter, P. A., Tuell, M. T., West, S. C., Woolf, N. J., Xin, B. 22 July 2016 (has links)
The LSST M1/M3 combines an 8.4 m primary mirror and a 5.1 m tertiary mirror on one glass substrate. The combined mirror was completed at the Richard F. Caris Mirror Lab at the University of Arizona in October 2014. Interferometric measurements show that both mirrors have surface accuracy better than 20 nm rms over their clear apertures, in near-simultaneous tests, and that both mirrors meet their stringent structure function specifications. Acceptance tests showed that the radii of curvature, conic constants, and alignment of the 2 optical axes are within the specified tolerances. The mirror figures are obtained by combining the lab measurements with a model of the telescope's active optics system that uses the 156 support actuators to bend the glass substrate. This correction affects both mirror surfaces simultaneously. We showed that both mirrors have excellent figures and meet their specifications with a single bending of the substrate and correction forces that are well within the allowed magnitude. The interferometers do not resolve some small surface features with high slope errors. We used a new instrument based on deflectometry to measure many of these features with sub-millimeter spatial resolution, and nanometer accuracy for small features, over 12.5 cm apertures. Mirror Lab and LSST staff created synthetic models of both mirrors by combining the interferometric maps and the small high-resolution maps, and used these to show the impact of the small features on images is acceptably small.
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Single Sign On med Azure AD Connect / Single Sign On with Azure AD ConnectBohman, Dan January 2016 (has links)
Den här rapporten handlar om Azure AD Connect och Single/Simplified Sign On. Användare och kunder idag ställer större krav för enklare inloggning och en mer sömlös upplevelse för åtkomst till alla IT-tjänster. Microsoft har nyligen släppt verktyget Azure AD Connect för synkronisering av lösenord mellan Active Directory och molntjänsterna Office365, Azure och 1000-tal SaaS ”Software as a service” applikationer. TeamNorr IT-partner är ett IT företag som riktar in sig på att leverera Microsofts produkter till sina kunder och vill därför veta mer kring Azure AD Connect, vad som krävs och hur det konfigureras. Single Sign On har betydelsen att bara behöver logga in en gång för att sen slippa skriva in användare och lösenord för att komma åt de applikationer som har stöd för Single Sign On. Federerad domän är det som ger bäst och säkrast upplevelse med Single Sign On. Simplified Sign On gör att samma användarnamn och lösenord används för inloggning, ingen automatisk inloggning sker. Azure AD Connect är verktyget som installerar de roller som behövs för att köra Single Sign On eller Simplified Sign On. Som standard installeras en synkroniseringsmotor som ska hålla koll på att informationen om användarna/grupperna och lösenorden stämmer mellan det lokala Active Directory och Azure Active Directory eller den federerade domänen. Det synkroniseringsmotorn tar med när den synkroniserar bestäms av de regler som satts upp. Används lösningen med Password Sync så tillkommer inga extra roller. Väljs istället en Federerad domän så installeras 2 extra roller som heter Federation(AD FS) och Web Application Proxy(WAP). Rollerna sköter autentisering av användarna istället för Microsofts autentisering. På servrarna som hostar rollerna krävs en viss grundprestanda beroende på storlek av Active Directory och antal användare anslutna för att det ska fungera tillfredsställande. / This report covers Azure AD Connect and Single/Simplified Sign On. Users and customers today places greater demand for easier login method and seamless experience for reaching all services. Microsoft has recently released Azure AD Connect tool to help synchronize passwords between Active Directory and the cloud services Office 365/Azure and 1000s of Software as a service applications. Team Norr IT-partner is an IT company that focuses on delivering Microsoft products to thier customers and therefore wanted to know more about Azure AD Connect. How to configure the solution and what the set requirements are. Single Sign On means that you only need to sign in with password and login once and automatically get access the applications that support the technology without any more credentials. By using a Federated domain users get the best and safest experience with Single Sign On. Simplified Sign On lets users use the same username and password to login with to all applications with support, but no automatic login. Azure AD Connect tool installs the roles that are needed to run a Single Sign On or Simplified Sign On. By default the synchronization engine will keep track of information about the users and groups. Passwords are also synchronized between on-premises Active Directory and Azure Active Directory or federation server. What the Synchronization engine takes is determined by the rules defined. Password Sync does not install any extra server roles. With the Federation path there will be extra roles installed called Federation (AD FS) and Web Application Proxy (WAP). They handle the authentication of users instead of the normal Microsoft authentication. There is some set requirement for the servers that host the roles depending on the size of Active Directory and numbers of users. The servers need a certain base performance for it to work properly.
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SPACE TELESCOPE AND OPTICAL REVERBERATION MAPPING PROJECT. IV. ANOMALOUS BEHAVIOR OF THE BROAD ULTRAVIOLET EMISSION LINES IN NGC 5548Goad, M. R., Korista, K. T., Rosa, G. De, Kriss, G. A., Edelson, R., Barth, A. J., Ferland, G. J., Kochanek, C. S., Netzer, H., Peterson, B. M., Bentz, M. C., Bisogni, S., Crenshaw, D. M., Denney, K. D., Ely, J., Fausnaugh, M. M., Grier, C. J., Gupta, A., Horne, K. D., Kaastra, J., Pancoast, A., Pei, L., Pogge, R. W., Skielboe, A., Starkey, D., Vestergaard, M., Zu, Y., Anderson, M. D., Arévalo, P., Bazhaw, C., Borman, G. A., Boroson, T. A., Bottorff, M. C., Brandt, W. N., Breeveld, A. A., Brewer, B. J., Cackett, E. M., Carini, M. T., Croxall, K. V., Bontà, E. Dalla, Lorenzo-Cáceres, A. De, Dietrich, M., Efimova, N. V., Evans, P. A., Filippenko, A. V., Flatland, K., Gehrels, N., Geier, S., Gelbord, J. M., Gonzalez, L., Gorjian, V., Grupe, D., Hall, P. B., Hicks, S., Horenstein, D., Hutchison, T., Im, M., Jensen, J. J., Joner, M. D., Jones, J., Kaspi, S., Kelly, B. C., Kennea, J. A., Kim, M., Kim, S. C., Klimanov, S. A., Lee, J. C., Leonard, D. C., Lira, P., MacInnis, F., Manne-Nicholas, E. R., Mathur, S., McHardy, I. M., Montouri, C., Musso, R., Nazarov, S. V., Norris, R. P., Nousek, J. A., Okhmat, D. N., Papadakis, I., Parks, J. R., Pott, J.-U., Rafter, S. E., Rix, H.-W., Saylor, D. A., Schimoia, J. S., Schnülle, K., Sergeev, S. G., Siegel, M., Spencer, M., Sung, H.-I., Teems, K. G., Treu, T., Turner, C. S., Uttley, P., Villforth, C., Weiss, Y., Woo, J.-H., Yan, H., Young, S., Zheng, W.-K. 03 June 2016 (has links)
During an intensive Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) UV monitoring campaign of the Seyfert 1 galaxy NGC 5548 performed from 2014 February to July, the normally highly correlated far UV continuum and broad emission line variations decorrelated for similar to 60-70 days, starting similar to 75 days after the first HST/COS observation. Following this anomalous state, the flux and variability of the broad emission lines returned to a more normal state. This transient behavior, characterized by significant deficits in flux and equivalent width of the strong broad UV emission lines, is the first of its kind to be unambiguously identified in an active galactic nucleus reverberation mapping campaign. The largest corresponding emission line flux deficits occurred for the high ionization, collisionally excited lines C IV and Si IV(+O IV]), and also He II(+O III]), while the anomaly in Ly alpha was substantially smaller. This pattern of behavior indicates a depletion in the flux of photons with E-ph > 54 eV relative to those near 13.6 eV. We suggest two plausible mechanisms for the observed behavior: (i) temporary obscuration of the ionizing continuum incident upon broad line region (BLR) clouds by a moving veil of material lying between the inner accretion disk and inner (BLR), perhaps resulting from an episodic ejection of material from the disk, or (ii) a temporary change in the intrinsic ionizing continuum spectral energy distribution resulting in a deficit of ionizing photons with energies > 54 eV, possibly due to a transient restructuring of the Comptonizing atmosphere above the disk. Current evidence appears to favor the latter explanation.
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