88 research outputs found
Manifestation of defects in phonon spectra of binary zinc-blende compounds
No full textIt is interesting to consider the problem of the presence of defects in the semiconductor binary compounds by observing their elemental tetrahedron distortions, caused by the creation of vacancies and interstitial atoms within the tetrahedra and so on. Our model thus considers the system A(Vz(x)Z(1-x)) and (A(1-y)Va(y))Z as composed of five defect tetrahedron configurations where A is a cation atom, Z an anion atom, V-alpha-cation vacancy, V-z-anion vacancy. In this communication we present far IR (FIR) spectra obtained at the DAFNE facility of Laboratori Nazionali di Frascati (INFN) using its synchrotron radiation. Two samples of CdTe are considered: sample-1 was grown by the PVT technique and sample-2 using the same technique but on the basis of, polycrystalline CdTe previously purified from oxygen in hydrogen atmosphere
Polyethylene Protective Coating with Anti-Reflective Properties for Silicon Photovoltaic Cells
No full textThe aim of the study was to find the effect of polyethylene (PE) coatings on the short-circuit current of silicon photovoltaic cells covered with glass, in order to improve the short-circuit current of the cells. Various combinations of PE films (thicknesses ranging from 9 to 23 µm, number of layers ranging from two to six) with glasses (greenhouse, float, optiwhite and acrylic glass) were investigated. The best current gain of 4.05% was achieved for the coating combining a 1.5 mm thick acrylic glass with 2 × 12 µm thick PE films. This effect can be related to the formation of an array of micro-wrinkles and micrometer-sized air bubbles with a diameter of 50 to 600 µm in the films, which served as micro-lenses and enhanced light trapping
Influence of hydrogen on hydrogenated cadmium telluride optical spectra
No full textThe presence of oxygen impurity in semiconducting materials affects the electrical properties of crystals and significantly limits their application. To remove oxygen impurity, ultrapure hydrogen is used while growing Te-containing crystals such as CdTe, CdZnTe, and ZnTe. The hydrogenation of CdTe crystals is a technological process that purifies the basic material from oxygen, mainly cadmium and tellurium oxide compounds incorporated in CdTe crystalline lattice. In the present work we analyses the deformations induced by hydrogen and oxygen atoms in CdTe crystals looking at their influence on the near fundamental band (NFB), middle infrared (MIR) and far infrared (FIR) reflectivity spectra as well as on cathodoluminescence (CL) spectra. Comparison of the hydrogenated CdTe phonon structure profiles confirms the presence of hydrogen atoms bounded inside the lattice. The possible localization of hydrogen and oxygen ions within the tetrahedron coordinated lattice is discussed in the framework of a model that shows a good agreement with recent NFB, MIR and FIR experiments carried out on hydrogenated CdTe crystals. Measured reflection spectra in the wavelength range 190-1400 nm (NFB) indicate the appearance in CdTe(HM) and CdTe(H L) of additional maxima at 966 nm related to the electron transitions from level about 0.2 eV above the valence band. The CL spectra confirmed existence of this electron level. We present a possible H2 alignment similar to the single H model i.e., over the face (at about 0.38 Å). For this model the angle from the central atom to the H atoms is equal to 64° which is also close to the bonding angle of CdH2 © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Creation of a pn heterojunction in Hg<sub>1−<i>x</i></sub>Cd<sub><i>x</i></sub>Te (<i>x</i> ≈ 0.2) by laser annealing
No full text A highly photosensitive diode area was created in solid solutions of Hg1−xCdxTe (x ≈ m 0.2) (MCT) without melting its surface. The idea of the possible formation of pn heterojunctions, which was indicated by computer modelling of the mass transportation processes under laser treatment of the MCT, was experimentally realized. MCT samples were irradiated with an Nd:YAG laser having an energy density of 0.7 J cm−2. The presence of a heterojunction on a surface not far below the upper surface has been verified by photovoltaic measurements and X-ray microanalysis as well as by current–voltage characteristics. </jats:p
A Case Study in the Desegregation of George Washington High School and Langston High School in Danville, Virginia during the 1970-1971 School Year
No full textThis paper provides a historical analysis of the desegregation of George Washington High School and Langston High School in Danville, Virginia in 1970. The author focuses on the related desegregation litigation on a national, state, and local level as well as the historical context for desegregation in the Commonwealth of Virginia.
In August of 1970, Danville, Virginia embarked on a new era in education as its schools would be totally desegregated. It would no longer operate under the freedom of choice plan that had been in effect since 1965 and permitted African-American parents to send their children to the all-white schools. The school system was to be fully integrated and operating as a unitary system.
Using newspaper accounts, correspondence from key figures, and interviews with key people in Danville in 1970, the author addresses four areas of research: (a) What led to the desegregation of schools in Danville, Virginia? (b) Who were the key players in the desegregation movement? (c) How were the community, the students, and the staff prepared for desegregation? and (d) What were the attitudes and the concerns about desegregation? The data was collected and analyzed using qualitative methodology. The constant-comparative method espoused by Maykut and Morehouse was used to analyze the data and Bronfenbrenner's concept of the "nested environment" was the theoetical model used to organize the data.Ed. D
Rezensionen
No full textDEUTSCHES POLEN-INSTITUT (ed.) (2006): Frauen. Jahrbuch Polen 2006. Wiesbaden: Harrassowitz. 205 S.
BONTER, URSZULA (2005): Der Populärroman in der Nachfolge von E. Marlitt. Wilhelmine Heimburg, Valeska Gräfin Bethusy-Huc, Eufemia von Adlersfeld-Ballestrem. Würzburg: Königshausen & Neumann. 276 S.
CORNEJO, RENATA (2006): Das Dilemma des weiblichen Ich. Untersuchungen zur Prosa der 1980er Jahre von Elfriede Jelinek, Anna Mitgutsch und Elisabeth Reichart. Wien: Praesens Verlag. 245 S.
ENGEL,MANFRED / LAMPING, DIETER (eds.) (2006): Franz Kafka und die Weltliteratur. Stuttgart: Vandenhoeck & Ruprecht. 378 S.
HAAS, AGNIESZKA KATARZYNA (2005): Polskie przekłady Fausta I Goethego. Próba krytyki i zarys recepcji w Polsce. [Polnische Übertragungen von Goethes Faust I. Versuch einer Kritik und eines Überblicks über die Rezeption in Polen]. Gdańsk: Uniwersytet Gdański (=Studia Germanica Gedanensia 12) . 291 S.
HARDER, MATTHIAS / HILLE, ALMUT (eds.) (2006): Weltfabrik Berlin. Eine Metropole als Sujet der Literatur. Studien zu Literatur und Landeskunde. Würzburg: Könighausen & Neumann. 306 S.
JAROSZEWSKI, MAREK (2006): Życie i twórczość E.T.A. Hoffmanna 1776-1822. [Leben und Werk von E.T.A. Hoffmann 1776-1822]. Gdańsk: WydawnictwoUniwersytetu Gdańskiego. 136 S.
SOMMERFELD, BEATE (2007): Kafka-Nachwirkungen in der polnischen Literatur. Unter besonderer Berücksichtigung der achtziger und neunziger Jahre des zwanzigsten Jahrhunderts. Frankfurt (M.)/Berlin/Bern/Bruxelles/New York/Oxford/Wien: Peter Lang Verlag (=Posener Beiträge zur Germanistik 14). 294 S.
SUROWSKA, BARBARA L. (2006): Von überspannten Ideen zum politischen Appell. 25 Essays zur deutschen Literatur. Warszawa: Zakład Graficzny Uniwersytetu Warszawskiego. 335 S.
EBERT, CHRISTA (2004): Sinaida Hippius. Seltsame Nähe. Ein Porträt. Berlin: Oberbaum Verlag. 393 S.
LÖW, ANDREA (2006): Juden im Getto Litzmannstadt. Lebensbedingungen, Selbstwahrnehmung, Verhalten. Göttingen: Wallstein (=Schriftenreihe zur Łódzer [sic!] Getto-Chronik). 584 S.
MÄRZ, PETER / VEEN, HANS-JOACHIM (eds.) (2006): Woran erinnern? Der Kommunismus in der deutschen Erinnerungskultur. Köln/Weimar/Wien: Böhlau Verlag. 269 S.
MÜNCH, RICHARD (2007): Die akademische Elite. Frankfurt (M.): Suhrkamp. 475 S.
ŻYCHLIŃSKI, ARKADIUSZ (2006): Unterwegs zu einem Denker. Eine Studie zur Übersetzbarkeit dichterischer Philosophie am Beispiel der polnischen Übersetzung von Martin Heideggers „Sein und Zeit“. Wrocław/Dresden: Oficyna Wydawnicza ATUT – Wrocławskie Wydawnictwo Oświatowe / Neisse Verlag. 374 S.
BREUER, ULRICH / HYVÄRINEN, IRMA (eds.) (2006): Wörter – Verbindungen. Festschrift für Jarmo Korhonen zum 60. Geburtstag. Frankfurt (M.)/Berlin/Bern/Bruxelles/New York/Oxford/Wien: Peter Lang Verlag. 516 S.
ŁYP-BIELECKA, ALEKSANDRA (2007): Verben der Nahrungsaufnahme des Deutschen und des Polnischen. Eine semanto-syntaktische Vergleichsanalyse.Frankfurt (M.)/Berlin/Bern/Bruxelles/New York/Oxford/Wien: Peter Lang Verlag (=Danziger Beiträge zur Germanistik 21). 246 S.
STEINITZ, KLAUS / KASCHUBA,WOLFGANG (eds.) (2006): Wolfgang Steinitz - Ich hatte unwahrscheinliches Glück. Ein Leben zwischen Wissenschaft und Politik. Berlin: Karl Dietz Verlag. 383 S.
ROCHE, JÖRG (2005): Fremdsprachenerwerb – Fremdsprachendidaktik. Tübingen/Basel: A. Francke Verlag. 282 S.
ZENDEROWSKA-KORPUS, GRAŻYNA (2004): Sprachliche Schematismen des Deutschen und ihre Vermittlung im Unterricht DaF. Frankfurt (M.)/Berlin/Bern/Bruxelles/New York/Oxford/Wien: Peter Lang Verlag (=Danziger Beiträge zur Germanistik 12). 238 S
Fatal enhanced respiratory syncytial virus disease in toddlers
No full textIn 1967, two toddlers immunized with a formalin-inactivated vaccine against respiratory syncytial virus (FIRSV) in the United States died from enhanced RSV disease (ERD), a severe form of illness resulting from aberrant priming of the antiviral immune response during vaccination. Up to 80% of immunized children subsequently exposed to wild-type virus were hospitalized. These events hampered RSV vaccine development for decades. Here, we provide a characterization of the clinical, immunopathological, and transcriptional signature of fatal human ERD, outlining evidence for safety evaluation of RSV vaccines and a framework for understanding disease enhancement for pathogens in general.Fil: Polack, Fernando Pedro. Vanderbilt University; Estados Unidos. Fundación para la Investigación en Infectología Infantil; ArgentinaFil: Álvarez Paggi, Damián Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Investigación en Infectología Infantil; ArgentinaFil: Libster, Romina Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Investigación en Infectología Infantil; ArgentinaFil: Caballero, Mauricio Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Investigación en Infectología Infantil; ArgentinaFil: Blair, Robert V.. University of Tulane; Estados UnidosFil: Hijano, Diego Raúl. Fundación para la Investigación en Infectología Infantil; Argentina. St. Jude Children’s Research Hospital; Estados UnidosFil: de la Iglesia Niveyro, Paola Ximena. Hospital Italiano; ArgentinaFil: Menendez, Franco Daniel. National Institute ff Environmental Health Sciences; Estados UnidosFil: Gladwell, Wes. National Institute ff Environmental Health Sciences; Estados UnidosFil: Avendano, Luis M.. Universidad Nacional de Chile; ChileFil: Velozo, Luis. Universidad Nacional de Chile; ChileFil: Wanek, Alanna. University of Tulane; Estados UnidosFil: Bergel, Eduardo. Instituto de Efectividad Clínica y Sanitaria; ArgentinaFil: Prince, Gregory A.. Independent Researcher; Estados UnidosFil: Kleeberger, Steven R.. Hospital Italiano; ArgentinaFil: Johnson, Joyce. Vanderbilt University; Estados UnidosFil: Pociask, Derek. University of Tulane; Estados UnidosFil: Kolls, Jay K.. University of Tulane; Estados Unido
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