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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 2241-2246 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: To improve beam quality, an injection-seeded unstable resonator was applied to a discharge-pumped F2 laser, which is normally dominated by amplified spontaneous emission with a large beam divergence when using a normal stable cavity, due to the laser's extremely high gain (a small-signal gain-length product ∼29). The time-dependent injection-seeding efficiency was obtained for various injection timings by measuring a ratio of the output laser intensity with the same polarization as the seed laser. Correlation of the injection-seeding efficiency with the temporal evolution of the laser-beam divergence was also studied. Both the time-dependent beam divergence and the injection-seeding efficiency showed degradation at a later part of the laser pulse.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 3131-3136 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report a calculation on the current-voltage characteristics of double-barrier resonant tunneling diodes. The results can well-explain experimental observations, in particular, the temperature dependence of both the absolute current amplitude and the resonant voltage positions. Our calculation takes into account the self-consistent Poisson equation, quantum mechanical tunneling, and band-gap offset at the heterojunctions. In addition, the calculation includes a realistic scattering-induced broadening effect, with which a quantitative fit throughout the entire negative differential resistance (NDR) region is demonstrated. Finally, we show that the differential resistance in the NDR region can be tuned, when asymmetrical tunneling barriers are used.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 671-675 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated magneto-transport and cyclotron resonance (CR) of two-dimensional electron gas in silicon δ-doped p-InSb under a magnetic field of up to 12 T at 4.2 K. Because there are multiple subbands occupied, Shubnikov–de Haas oscillations show a beating behavior. The CR spectra also display several peaks originating from different subbands. Effective masses of electrons associated with the lowest three subbands can therefore be directly determined, and they are in excellent agreement with a self-consistent calculation, which takes into account the electrostatic Poisson equation, the Schrödinger equation, and realistic sample parameters. Furthermore, we observed an absorption peak, whose resonance position has anomalous angle dependence. It is attributed to impurity CR where donors are in the vicinity of the δ-doped sheet.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 1537-1539 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present quantum mechanical self-consistent calculations on the transfer characteristics of a new resonant tunneling transistor. The model structure consists of a source, a tunneling barrier, a quantum-well drain, a thick insulator, and a backgate. The tunneling barrier consists of a double-barrier structure. We demonstrate that based on energy and momentum conservations, the transistors display oscillatory negative transconductance, as the gate can control the resonant tunneling probability between source and drain. With the inclusion of a realistic energy relaxation time of ∼0.1 ps, the double-barrier resonant tunneling transistor shows an enhancement of the tunneling current density and the negative transconductance feature is only slightly changed. We also find that the quantum-well drain is not able to completely screen the electric field imposed by the backgate bias as a result of limited density of states of two-dimensional systems.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 4132-4134 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We investigated the current-voltage characteristics of double-barrier resonant tunneling diodes with areas ranged from ∼400 μm2 to ∼10 μm2 at a temperature of 300 and 4.2 K. For diodes of large areas, the characteristic negative differential resistance is always accompanied by a hysteresis and oscillation at several tens of MHz. However, for smaller diodes, the hysteresis and oscillation disappear, and the tunneling current shows a smooth transition between peak and valley. Our observation shows that the hysteresis can result from a load line effect. Were the hysteresis an intrinsic behavior, it should persist as the device area is reduced. We therefore conclude that the intrinsic bistability is yet to be experimentally confirmed.
    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 70 (1991), S. 2208-2210 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We show that for narrow band-gap semiconductors, the doping concentration deduced from capacitance-voltage measurements can be substantially underestimated due to surface quantization effect. While our derivation can be applied to all materials, detailed accounts on p-type Hg0.788Cd0.212Te are given as an example. We found that for a practical doping range, 1×1015 cm−3 to 1×1017 cm−3, the doping level can be underestimated by 53% to 173%, respectively.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 2473-2475 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report experimental observation on the area and temperature dependence of the hysteresis in the current-voltage characteristics of double-barrier resonant tunneling diodes. Our observation shows that the hysteresis can simply result from a load line effect, since (1) the hysteresis will disappear when the the device area is reduced, and (2) the hysteresis becomes wider at lower temperatures. We compare the data with theoretical predictions from the intrinsic bistability picture, and obtain the criterion for observing current bistability.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Clinical and experimental dermatology 30 (2005), S. 0 
    ISSN: 1365-2230
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A 34-year-old woman presented with 2-year history of a dome-shaped papule on a well-circumscribed, thickened, port-wine stain on the left side of the chin. Squeezing on the port-wine-stain plaque revealed many comedos within dilated follicular orifices. The papule was excised and submitted for histological examination. Histopathological study showed a lobular neoplasm, comprising dilated, cystic pilosebaceous structures surrounded by fibrous stroma, bearing the characteristics of folliculosebaceous cystic hamartoma. The reported case shows that, in addition to the vascular nature, both ectodermal and mesenchymal abnormalities may be involved in port-wine stains.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    British journal of dermatology 142 (2000), S. 0 
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Docetaxel (Taxotere®), a semisynthetic taxoid, acts as an antimicrotubule agent and is considered to have great potential in the treatment of non-small cell lung cancer, advanced breast cancer, ovarian cancer and some other tumours. Well-recognized side-effects include dose-limiting neutropenia, fluid retention, myalgia, neuropathy, hypersensitivity reaction, alopecia, mucositis, nail changes and cutaneous reactions such as acral erythema. We describe a unique docetaxel-induced cutaneous reaction presenting as fixed erythematous plaque(s) unrelated to extravasation or previous skin injury; histopathological studies were performed in three of the four cases.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 30-38 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Theoretical analysis of the output performance of a transverse discharge pumped neon Penning laser (585.3 nm) using a mixture of Ne/H2 is described. The validity of the kinetic model is confirmed by comparing the results to the experimental discharge and laser performance. It is theoretically shown that the optimum mixing ratio of the Ne/H2 mixture is 1:2.5, and the optimum operating pressure is about 56 Torr. The model also predicts that the intrinsic efficiency reaches a peak of 8.5×10−6 at an excitation rate of 0.5 MW/cm3 under the optimum mixing ratio and operating pressure conditions. At excitation rates in excess of 0.5 MW/cm3 the laser output power is slowly increasing and then saturates due to electron collisional quenching of the upper laser level. The laser power extraction is increased by laser injection seeding in order to rapidly build up the lasing. The improved intrinsic efficiency is about two times higher than without the injection seeding. The improved specific laser output is 8 W/cm3, therefore, a discharge volume of 125 cm3 will be able to generate the peak laser power reaching 1 kW. This power value is sufficient to obtain the same treatment effect as the gold vapor laser used in photodynamic therapy. Moreover, by fitting this model to the experimental results of the laser output energy with a Ne/D2 mixture, it is shown that the Penning ionization rate constant of H2 is larger than that of D2. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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