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  • 1990-1994  (172)
  • 1975-1979  (95)
  • 1970-1974  (77)
  • 1
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Journal of medicinal chemistry 15 (1972), S. 281-285 
    ISSN: 1520-4804
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 1014-1022 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Time-zero current-voltage characteristics and time-dependent current behavior of metal-ferroelectric-metal (Pt-PZT-Pt) capacitor structures have been studied. Under constant-voltage stressing, the current density through the 1500-A(ring)-thick lead-zirconate-titanate (PZT) film exhibits a power-law dependence on time, with the exponent (∼0.33) independent of temperature and voltage. Electrode material dependence of current density indicates that the conventional model of trap-limited single-carrier injection over nonblocking contacts is inadequate to explain the time-zero current. A change in top electrode material from Pt to In leads to the observation of work-function-driven Schottky contacts between the metal and ferroelectric. The current-voltage characteristics fit a two-carrier injection metal-semiconductor-metal model incorporating blocking contacts, with distinct low- and high-current regimes (PZT is assumed to be p-type and trap-free in this model). Temperature-dependent I-V measurements indicate a Pt-PZT barrier height of 0.6 eV and an acceptor doping level of ∼1018 cm−3 in PZT. The implications of this model on the optimization of ferroelectric capacitors for dynamic random access memory applications are discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 84 (1977), S. 0 
    ISSN: 1471-0528
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The effects of autoimmune (or idiopathic) thrombocytopenic purpura (ATP) on 51 pregnancies in 29 women is presented. There is no convincing evidence that the clinical course of ATP is influenced by pregnancy. There was no increased incidence of obstetric complications. No problems were encountered following spontaneous vaginal delivery or low forceps delivery. There were no perinatal deaths. Twenty newborn infants were studied in detail and significant thrombocytopenia was present in half of them. The severity of thrombocytopenia in the newborn correlated closely with the severity of maternal disease; those women in clinical remission following splenectomy but with presumed high levels of antiplatelet antibodies were those most likely to be delivered of affected newborn infants. The cord blood platelet count was the most reliable guide to the potential severity of the neonatal thrombocytopenia. Platelet counts were lowest between the second and fourth days of neonatal life. The management of the severely affected infant is discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 80 (1973), S. 0 
    ISSN: 1471-0528
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Serum cholesterol and lipoprotein-triglyceride were measured in 38 women before and during treatment with the progestogen, norethisterone, as part of a trial of the agent for use as an oral contraceptive. Levels of cholesterol and lipoprotein-triglyceride were found to fall during treatment. Before starting treatment with norethisterone some of the subjects had been taking either combined oestrogenl progestogen preparations or chlormadinone acetate as oral contraceptives. The fall in cholesterol levels appeared to be more marked in these women than in those not previously treated. The fall in lipoprotein-triglyceride was of a similar degree in those not pretreated and those previously taking combined oestrogen/progestogen contraceptives.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    ISSN: 1520-5835
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Macromolecules 8 (1975), S. 680-684 
    ISSN: 1520-5835
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: This project developed an automated controller based on an artificial neural network and evaluated its applicability in a real-time environment. This capability was developed within the context of a small angle negative ion source on the Discharge Test Stand at Los Alamos. The controller processes information obtained from the beam current wave form, developing a figure of merit (fom) to determine the ion source operating conditions. The fom is composed of the magnitude of the beam current, the stability of operation, and the quietness of the beam. Using no knowledge of operating conditions, the controller begins by making of rough scan of the four-dimensional operating surface. This surface uses as independent variables the anode and cathode temperatures, the hydrogen flow rate, and the arc voltage. The dependent variable is the fom described above. Once the rough approximation of the surface has been determined, the network formulates a model from which it determines the best operating point. The controller takes the ion source to that operating point for a reality check. As real data is fed in, the model of the operating surface is updated until the neural network's model agrees with reality. The controller then uses a gradient ascent method to optimize the operation of the ion source. Initial tests of the controller indicate that it is remarkably capable. It has optimized the operation of the ion source on six different occasions bringing the beam to excellent quality and stability.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 5408-5410 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A two-dimensional finite-element method was used to model a horizontal magnetoresistive head in order to test the fabrication design parameters. The device consists of two magnetoresistive elements placed closely together and parallel to the plane of the media, following a design of Chapman, Heim, and Williams [IEEE Trans. Magn. MAG-25, 3689 (1989)]. A single transition in the media was moved, in steps, past the head. The electrical signal strength and pulse width, due to this transition, were studied as a function of the shield permeability, thickness and shield gap, the sensor-sensor distance, the flying height, and sensor-shield distance. The width of the pulse did not show appreciable change with shield thickness, permeability, or shield gap size, although the signal strength changed significantly. A thin shield (1000 A(ring)) of moderately low permeability (2000) is therefore preferred. The signal fell off almost exponentially with flying height and sensor-shield separation. The situation where no shield was present was also simulated and showed a reasonably narrow pulse with a large undershoot and a long tail. These results indicate the horizontal head suggested by Chapman and co-workers may in fact provide good readback resolution with a thin shield or perhaps no shield whatsoever.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 1764-1772 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Using x-ray diffraction, Rutherford backscattering spectrometry, Auger electron spectroscopy, and scanning electron microscopy, effects of ambient anneal and Pt thickness on the interdiffusion of Pt/Ti bilayers deposited on SiO2/Si and on reactively sputtered TiN/Ti/Si substrates have been investigated. The Pt layer was 2000 or 930 A(ring) thick while the Ti thickness was fixed at 1000 A(ring). The wafers were annealed in either O2 or N2 ambients or in N2 followed by O2, with temperatures ranging from 600 to 800 °C for 30 min. The anneal ambients and the thickness of Pt relative to the Ti layer had tremendous effects on the interdiffusion processes, the reaction products, and the surface morphology of the multilayer structures. Samples annealed in O2 were generally rough, with bumps of the order of 1000 A(ring), while those annealed in N2 were relatively smooth. With lead zirconium titanate on top, the surface of Pt/Ti electrode annealed in O2 at 650 °C was relatively smooth.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 1674-1682 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Intense rare gas-halide and rare gas-oxide excimer emission has been observed by coupling a pulsed electric discharge to a supersonic free jet expansion. A simple modification in the placement of the discharge anode drastically reduces the number of energetic electrons in the supersonic expansion region and permits large peak excimer populations to be produced by harpoon collisions involving rare gas metastables. The expansion velocity has been determined by spatially resolved spontaneous emission and laser-induced fluorescence measurements. Strong emission spectra from XeF, XeCl, KrF, KrCl, ArF, and the 2 3Π ion pair state of XeO have been recorded.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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