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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Mathematische Annalen 316 (2000), S. 83-102 
    ISSN: 1432-1807
    Keywords: Mathematics Subject Classification (1991):32A35, 32A37, 42B30, 47A10
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract. We prove new sharper estimates of solutions to the $H^p$ -corona problem in strictly pseudoconvex domains; in particular we show that the constant is independent of the number of generators. We also obtain sharper estimates for solutions to the BMOA corona problem. The proofs also lead to new results about the Taylor spectrum of analytic Toeplitz operators on $H^p$ and BMOA.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 4239-4250 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A collision complex that gives almost quantitative agreement with a large set of data for inelastic scattering of atoms and molecules from surfaces is presented. In the model, a scattering molecule and a small part of the surface form a collision complex, that decomposes in a unimolecular fashion after statistical redistribution of energy. Both molecular translation and rotation are included in the model, and the surface is represented by a small number of harmonic oscillators. The surface is considered as locally flat at the place of impact, and surface corrugation is represented by a Gaussian distribution of local normal directions. Analytical solutions of simple integrals clearly illustrate the functional dependence on the principal parameters: translational energy, scattering angle, surface temperature, the relative size of the surface directly interacting with a scattering molecule, and the active degrees of freedom. Angular distributions for atoms, diatomic and polyatomic molecules scattering from metals, graphite and liquid surfaces are shown to be in good agreement with experimental results at thermal translational energies, and at least up to 0.5 eV. The model provides a simple and useful way to interpret and inter-relate experimental results, and makes it possible to evaluate the total information content in experimental data. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1520-4812
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Observations of discrete conductance fluctuations are reported at voltages well below the breakdown voltage in selected reverse-biased p+-n++ base-emitter junctions originating from gate turn-off thyristors. The occurrence of the phenomenon is attributed to the presence of defect clusters at the p-n junctions. The defect clusters introduce field confinements which activate tunneling processes that would not otherwise be present in these nonabrupt p-n junctions. The fluctuating reverse current was only observed in voltage and temperature regions where the total reverse current was influenced by tunneling-related conduction mechanisms. The experimental observations concerning the voltage and temperature dependences of the fluctuation amplitude and rate deviate from earlier reports on decisive points. Both the amplitude and the switching rate of the observed fluctuations were unstable in time and influenced by the measurement procedure itself. This instability is attributed to small structural changes of the defect clusters. Furthermore, the unstable behavior of the defect clusters also influences the static reverse current-voltage characteristic. Distinct changes were found in the static reverse current-voltage characteristics of selected samples due to high-energy electron irradiation and annealing at 200 °C. A clearly increased uniformity of the reverse current-voltage characteristics between the gate-cathode junctions of gate-turn off thyristors was also found as a result of electron irradiation. The changes observed are interpreted as evidence of structural changes of the defect clusters.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 3232-3239 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have studied the size-dependent reactivity of W10–W60 with N2 under single-collision-like conditions by using a laser-vaporization source, a low-pressure reaction cell and a laser-ionization time-of-flight mass spectrometer. The reaction probability with the first and second N2 molecule was measured at two different cluster-source temperatures: room temperature (RT) and liquid-nitrogen temperature (LNT). For the RT clusters, a strong size dependence in the reaction probability was observed in the size range ∼10–26 atoms, with distinct local maxima at W16, W22, and W23. Upon cooling of the cluster source, the reaction probability increased significantly overall, and the relative variations with size decreased, but persisted. To get an indication of the bond strength of N2 on Wn, we heated the cluster products after reaction through irradiation with 4.02 eV photons from a XeCl excimer laser and checked for consequent desorption of adsorbate atoms or molecules. For the LNT clusters, heating with laser light caused a substantial decrease in the abundance of reaction products with nitrogen, whereas no significant change in the abundance of WnN2 was observed for the RT clusters. This indicates that a proportion of the N2 is relatively weakly bound to the LNT clusters, whereas on Wn produced at RT, only the strongly bound state/states of N2 exist. Based on comparisons with the N2-adsorption on W bulk surfaces, we conclude that the weakly and strongly bound states represent molecularly and dissociatively bound N2, respectively. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 124-140 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electrical and optical properties of wafer bonded unipolar silicon-silicon junctions were investigated. The interfaces, both n-n type and p-p type, were prepared using wafers with hydrophilic surfaces. The current versus voltage characteristics, the current transients following stepwise changes in the applied bias, and the capacitance versus voltage characteristics as well as the temperature dependence of the current and capacitance were experimentally obtained and theoretically modeled. The proposed model assumes two distributions of interface states, one of acceptors and one of donors, causing a potential barrier at the bonded interface. It is argued that the origins of the interface states are impurities and crystallographic defects in the interfacial region. The capacitance of the bonded structures includes contributions from the depletion regions as well as from minority carriers. When bonded n-n type samples were illuminated with light of photon energies larger than the silicon band gap the current across the junction increased. This is caused by the photogenerated increase in the minority carrier concentration in the interfacial region, which results in a lowering of the potential barrier. Illumination of n-n type structures with light of photon energies lower than the band gap caused a considerable photocurrent at low temperatures. In this case the observed behavior cannot be explained by interaction with the interface states. Instead, the mechanism is the change in the occupancy of deep electron traps caused by the illumination. These traps are located in the silicon in a small volume around the bonded interface with energies close to the center of the band gap and with a peak concentration of about 1013 cm−3. Impurities present on the silicon surfaces before bonding and impurities gettered to the bonded interface are possible reasons for the increased concentration of deep electron traps in the vicinity of the bonded interface.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Gain narrowing and lasing from a soluble, highly photoluminescent conjugated polymer, poly(2-butyl, 5-(2′-ethyl-hexyl)-1,4-phenylene vinylene) (BuEH-PPV), are compared using two resonant structures: planar waveguides and microcavities. The gain narrowing and lasing thresholds are comparable, 0.05–0.1 μJ (10 ns pulse focused to ∼1.5 mm). Gain narrowing is not observed in films on indium tin oxide (ITO) unless a cladding layer is placed between the BuEH-PPV and ITO. Single-mode microcavity lasers are obtained when a cavity resonance occurs at the wavelength where the gain of the polymer is maximum. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Futura Publishing, Inc.
    Pacing and clinical electrophysiology 24 (2001), S. 0 
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: ENGLUND, A., et al.: Dispersion in Ventricular Repolarization in Patients with Severe Intraventricular Conduction Disturbances. Increased dispersion of repolarization, measured invasively or by QT interval measurements, is associated with an increased risk for ventricular arrhythmias and sudden death. Most studies on this issue have included patients with normal intraventricular conduction, and it is not known if this finding has a predictive value also in patients with intraventricular conduction disorders. An invasive electrophysiological study, including programmed ventricular stimulation and assessment of effective refractory periods at two RV sites, was performed in 103 patients with bifascicular block (mean age 67 ± 12 years). QT dispersion was measured from standard 12-lead ECGs. In patients with inducible sustained polymorphic VT or VF the dispersion in refractoriness between the two RV sites was significantly greater (46 ± 11 ms, n = 13) than in noninducible patients (14 ± 14 ms, n = 84) and in patients with inducible sustained monomorphic VT (16 ± 5 ms, n = 6) (P 〈 0.01). Similarly, QT dispersion was 104 ± 46 ms, 66 ± 31 ms, and 77 ± 33 ms, respectively, in the three groups (P 〈 0.05). Dispersion in repolarization, neither measured invasively nor by QT interval measurements, predicted sudden death, all cause mortality, or ventricular arrhythmia during a mean follow-up period of 3 years. In patients with bifascicular block, there is a relation between the degree of dispersion of ventricular repolarization and the inducibility of polymorphic ventricular arrhythmia, but this outcome did not occur during follow-up.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 540 (1988), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature structural biology 4 (1997), S. 793-795 
    ISSN: 1072-8368
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Sir — Porcine NK-lysin is a basic polypeptide of 78 amino acid residues with marked antibacterial activity and the capability to lyse tumour cell lines but not red blood cells. Its presence in CD2+, CD4+, and CD8+ cells suggests a function as an effector polypeptide of T- and NK-cells1. The ...
    Type of Medium: Electronic Resource
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