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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 4411-4420 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A method to deduce energy distributions of defects in the band gap of a semiconductor by measuring the complex admittance of a junction is proposed. It consists of calculating the derivative of the junction capacitance with respect to the angular frequency of the ac signal corrected by a factor taking into account the band bending and the drop of the ac signal over the space charge region of the junction. Numerical modeling demonstrates that defect distributions in energy can be reconstructed by this method with high accuracy. Defect distributions of polycrystalline Cu(In,Ga)Se2 thin films are determined by this method from temperature dependent admittance measurements on heterojunctions of Cu(In,Ga)Se2 with ZnO that are used as efficient thin film solar cells. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 2888-2890 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Admittance spectroscopy was measured on Cu(In,Ga)(S,Se)2 thin film and single crystal heterojunctions. The emission rates of defects for various near-stoichiometric compositions follow a Meyer–Neldel rule, showing increasing attempt-to-escape frequencies with increasing defect depth. Defects in highly (In,Ga)-rich material showed lower attempt-to-escape frequencies and follow a separate Meyer–Neldel relation. Repetitive air annealing of a CuInSe2 heterojunction revealed a shift of the depth and capture cross section of an observed defect. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 2490-2495 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Results of a pilot study with a spectro-streak apparatus applying a grating microspectrometer with a self-focusing reflection grating are reported. The microspectrometer chip (dimensions: 17×6.4 mm2; 125 μm effective thickness of the three-layer x-ray resist system), fabricated with the versatile LIGA technique, has been adapted to a picosecond streak camera. Performance tests have been carried out with a fluorescent probe exhibiting a dynamic Stokes shift of the exciplex fluorescence band due to solvation of the charge transfer dipole within about 400 ps. The use of a LIGA microspectrometer in ultrafast spectroscopy proved to be of advantage in time-resolved studies of complex luminescence spectra where a moderate spectral resolution is required and a large spectral range must be covered. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 25-27 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of a postdeposition anneal on the structure and dielectric properties of epitaxial BaxSr1−xTiO3 (BST) thin films (x=0.35–0.65) have been measured. The films were grown by pulsed laser deposition on LaAlO3 (001) substrates. The films were single phase and (001) oriented with a lattice parameter larger than the bulk. The dielectric properties of the x=0.35 film exhibited a broad temperature dependence and a peak at 168 K, which is 36 K below the peak observed in bulk BST (x=0.35). Annealing films for 8 h in flowing oxygen at 900 °C caused the lattice parameter to decrease and dielectric properties to become more like the bulk. Annealing also resulted in an increased electric field dependent dielectric tuning without increased dielectric loss. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Terra nova 7 (1995), S. 0 
    ISSN: 1365-3121
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Several Miocene basins are developed on a mosaic of deformed Mesozoic carbonate platforms and ophiolitic units in the Antalya region of south-west Turkey. Two of these, the Manavgat and Köprü basins, show contrasting orientations and stratigraphies. The Manavgat basin is orientated broadly SE-NW and contains a succession of shallow-water reef carbonates overlain by a thick sequence of deeper-water marls. The upper part of the succession consists of sandstones, siltstones and conglomerates, mainly deposited by gravity processes. The stratigraphy of the N-S Köprü basin can be subdivided into a western part, which consists of coarse fan delta-conglomerates with local patch reefs, and an eastern part with thinly bedded sandy turbidites. Tooi marks indicate north to south flow in the north of the basin, but a southeasterly direction in the area of intersection with the Manavgat basin in the south-east. In the light of alternative regional hypotheses, it is thought that early Miocene basin initiation is related to coeval southeastward thrusting of the Mesozoic Lycian Nappes. Flexural loading is inferred to have resulted in block faulting of the foreland and this exploited pre-existing lines of structural weakness, dating from early Mesozoic rifting. mid-Miocene relative sea- level rise may relate to global eustacy, and/or regional tectonic subsidence. Finally, late Miocene renewed coarse clastic input (locally very coarse) and basin infilling reflect tectonic uplift to the north, possibly related to continuing Africa-Eurasia convergence in the region.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, U.K. and Cambridge, USA : Blackwell Science Ltd
    Scandinavian journal of immunology 43 (1996), S. 0 
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Natural killer (NK) cells in HIV-infected patients have a reduced ability to generate non-MHC restricted cytotoxicity to a variety of target cells. The authors investigated antibodies to NK cells in HIV-infected patients and evaluated effects of these antibodies to NK cell numbers and function. Antibodies to NK cells were determined in 160 HIV-infected patients and 35 healthy controls. Flow cytometric whole blood methods were developed to detect antibodies to NK cells. Antibodies to asialo-GM1 were detected by TLC immunostaining. The presence of antibodies to NK cells was demonstrated in plasma of about one-third (54/160) of HIV-infected patients but rarely in controls (2/35). Autoantibodies bound to NK cells in vivo and were detected by a strong increase of surface immunoglobulin (Ig) on NK cells of HIV-infected patients. Anti-NK cell antibodies were warmreactive antibodies rather of IgG than of IgM phenotype. The prevalence of specific antibodies to asialo-GM1 was low (12.5%). Numbers of circulating NK cells did not differ significantly between antibody positive (99.5/μl) and antibody negative (141/μl) patients (P = 0.3). However, pre-incubation of healthy donors' NK cells with autoantibody positive plasma significantly inhibited cytotoxicity to K562 leukaemic cells (P = 0.002). Autoantibodies to NK cells in HIV-infected patients are present in the plasma of one-third of HIV-infected patients and are bound to NK cells in vivo. There is evidence that these autoantibodies can induce NK cell defects similar to those seen in vivo
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Materials Research 28 (1998), S. 397-419 
    ISSN: 0084-6600
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Perovskite, ferroelectric and paraelectric, thin films exhibit outstanding dielectric properties, even at high frequencies (〉1 GHz). This feature makes films such as (Ba,Sr)TiO3 and Pb(Zr,Ti)O3 ideally suited for a wide range of capacitor applications, particularly decoupling capacitors and tunable microwave capacitors; the latter application has been fueled by the recent explosion in wireless communications. The successful implementation of these materials as high-frequency dielectrics requires a detailed understanding of both their processing and materials properties.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 20 (1997), S. 0 
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract— The solute-rich beta titanium alloy Ti-3Al-8V-6Cr-4Mo-4Zr was subjected to 1500 bar nitrogen pressure at elevated temperatures (500–920°C), leading to a diffusion layer with a high surface hardness. Microstructural, crystallographic and compositional analyses indicate that TiN (δ) and Ti2N (ε) are formed at temperatures exceeding 815°C. The increased concentration of nitrogen, which is a potent α-stabilizer in titanium, also causes α-Ti to form near the surface. The nitriding treatment does not significantly alter the tensile properties or fatigue limit in solution heat treated material. A subsequent ageing treatment of 72 h at 440°C and 16 h at 500°C reduces toughness significantly, allowing cracks induced by nitriding to propagate more easily into the bulk. Tensile ductility and fatigue performance of aged nitrided Ti-3Al-8V-6Cr—4Mo-4Zr are thus significantly lower than in the untreated reference condition.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 52 (1996), S. 2750-2752 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz 42 (1999), S. 187-195 
    ISSN: 1437-1588
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The term „Ecstasy” includes a group of different methylenedioxyamphetamines which produce hallucinogenic activity, stimulation and the so-called ëentactogenic’ effects. –„Entactogen” is usually translated as „producing a touching within” or „creating an internal contact” and refers to the special psychotropic effect of this substances. Entactogens have been reported to make users aware of previously unconscious feelings and experiences. The „entactogenic” effect is the most typical of the psychedelic effects n 3,4-methylenedioxyamphetamine (MDMA). MDMA induces euphoria and acts stimulating, but the most common effect of MDMA is a heightened sense of „closeness” with other people. The negative effects, especially depression and a general sense of anxiety, may endure after the acute phase of ecstasy. Ecstasy is not a novel substance. However, the rapid spread connected with the arising techno-scene and the increasing prevalence of ecstasy-use world-wide is unprecedented. Epidemiological research of the last two years provides insights going further than just showing increasing numbers in the criminal statistics (e.g. ecstasy seizures; number of ecstasy users who became conspicuous the first time). According to surveys the lifetime prevalence of ecstasy is highest in the context of the techno culture, where ecstasy is mainly taken as a recreational drug. However, there seems to be a consumer group who exhibit extreme patterns of use and a high degree of psychic dependency. These consumers may be jeopardised by medical and psychiatric complications. The complications are due to the central and peripheral serotonergic effects of ecstasy. There are also neurotoxic side effects of ecstasy clearly proven in animal models and recently, for the first time, also shown in humans. The rate of psychic dependency is surprisingly high. Possible neurotoxic effects may be irreversible. In the face of the risks and the rapid spread of ecstasy suitable primary and secondary prevention is needed. Until now this has not been accomplished by the established structures.
    Notes: Zusammenfassung Ecstasy ist ein Sammelbegriff für verschiedene Methylendioxyamphetamine mit antriebssteigernder und halluzinogener Wirkung, die darüber hinaus eine sogenannte „entaktogene” Wirkung aufweisen. Der Begriff „entaktogen” wird als „im Inneren ein Gefühl erzeugen” oder „Herstellen einer inneren Berührung”übersetzt und charakterisiert die Wirkung psychoaktiver Stoffe, die unbewußte Gefühle und Erfahrungen wieder zugänglich machen und die Selbstreflexion fördern. Bei 3,4 Methylendioxymethamphetamin (MDMA) als Hauptvertreter dieser Gruppe steht diese entaktogene Wirkung im Vordergrund des erstrebten Rausches. Darüber hinaus erzeugt MDMA neben den auch vorhandenen antriebssteigernden und euphorisierenden Wirkungen ein Gefühl der großen Nähe zu anderen Menschen. Negative psychotrope Wirkungen können den akuten Rausch überdauern und werden vor allem in Form von depressiver Verstimmung und Angst erlebt. Ecstasy ist keine neue Substanz. Neu ist jedoch das Ausmaß und die Geschwindigkeit, mit der sich Ecstasy – gekoppelt an die Verbreitung der Techno-Party-Szene – weltweit durchgesetzt hat. Epidemiologische Untersuchungen der letzten zwei Jahre vermitteln Einblicke, die über die eindrücklichen Steigerungsraten der Bundeskriminalstatistiken (Sicherstellungsmengen; Anteil an den erstauffälligen Konsumenten) hinausgehen. Die aus Repräsentativerhebungen und Erhebungen in der Technoszene ermittelte Lebenszeitprävalenz für Ecstasy bestätigen den intensiven Gebrauch vor allem in dieser Szene als sog. „Freizeitdroge”. Darüber hinaus zeichnet sich jedoch die Existenz einer Konsumentengruppe mit exzessiven Gebrauchsmustern und psychischer Abhängigkeit ab. Für diese Gruppe wird ein erhebliches Risiko hinsichtlich medizinischer oder psychiatrischer Komplikationen angenommen. Diese Komplikationen lassen sich auf zentrale und periphere serotonerge Wirkungen von Ecstasy zurückführen bzw. durch die neurotoxischen Wirkungen von Ecstasy erklären. Die Quote psychisch abhängiger Ecstasy-Konsumenten ist überraschend hoch. Die möglichen neurotoxischen Wirkungen sind eventuell irreversibel. Die Risiken und die Ausbreitungsgeschwindigkeit von Ecstasy zeigen die Notwendigkeit geeigneter primär- und sekundärpräventiver Maßnahmen, die durch das herkömmliche Drogenhelfersystem bislang nur unzureichend geleistet werden konnten.
    Type of Medium: Electronic Resource
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