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  • 1995-1999  (36)
  • 1990-1994  (40)
  • 1985-1989  (14)
  • 1975-1979  (5)
  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 1714-1719 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A beam chopping system for a cyclotron is in operation at the JAERI cyclotron facility. A combination of a pulse voltage chopper in the injection line and a sinusoidal voltage chopper after the exit of the cyclotron is adopted to produce beam pulses spaced at 1 μs–1 ms intervals from natural cyclotron beams. The chopping system was designed according to a simple formulation of the chopping process in which the multiturn extraction was taken into account. Performance of the chopping system was experimentally proved to satisfy requirements of the design. In actual operation to produce beam pulses at long intervals, however, the number of the multiturn extraction is usually larger than the assumed value in the design because of a large phase acceptance of the cyclotron. Careful tuning of the acceleration phase width or the base magnetic field of the cyclotron is necessary to reduce it. It is essential to strictly define the acceleration phase of injected beams in the central region of the cyclotron to improve this situation. © 1997 American Institute of Physics.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 39 (1992), S. 0 
    ISSN: 1550-7408
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: . First and second generation schizogony of Leucocytozoon caulleryi occurred in chickens infected with sporozoites. First generation schizogony was studied by light and electron microscopy. First-generation schizonts were first detected in capillary endothelial cells in the spleen, lung, liver, and bursa of Fabricius between 3 and 6 d post-sporozoite inoculation (DPI). The schizonts ranged from 15 to 65 μm in diameter and were surrounded by a thin pellicle. Early schizonts contained numerous round or oval nuclei, endoplasmic reticulum, and mitochondria. The schizonts reached maturity 5 DPI and produced first-generation merozoites which were released into the peripheral bloodstream. The merozoites. which were infective to chickens, measured 7.1 μm in length. They were slender and had a large nucleus, a mitochondrion, and an apical complex consisting of three polar rings, rhoptries, numerous micronemes. The morphology of first-generation merozoites was different from that of second-generation merozoites.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 3881-3883 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The first subband energy at the valence band of self-assembled silicon quantum dots grown by low-pressure chemical vapor deposition on ultrathin SiO2/Si substrates has been measured as an energy shift at the top of the valence band density of states by using high-resolution x-ray photoelectron spectroscopy. The systematic shift of the valence band maximum towards higher binding energy with decreasing the dot size is shown to be consistent with theoretical prediction. The charging effects of the silicon dots and the SiO2 layer by photoelectron emission during the measurements have been taken into account in determining the valence-band-edge energy. © 1998 American Institute of Physics.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 496-499 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Some degradation modes of 1.3 and 1.55 μm buried heterostructure distributed feedback (DFB) lasers grown by liquid-phase epitaxy are clarified. A degradation mode induced by the inhomogeneous optical-field distribution along the laser cavity is found to exist in DFB lasers. In most DFB lasers, the interface degradation between first growth-step (double heterostructure) layers and second growth-step (burying) layers occurs in the same manner as Fabry–Perot lasers.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 2049-2051 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Chemical shifts of Si–Hx (x=1,2) species on Si surfaces obtained by ex situ chemical treatment have been evaluated by high-resolution x-ray photoelectron spectroscopy at a take-off angle of 5°. Optimizing the water rinse and sample loading conditions enables identification of the Si–Hx components of the Si 2p core-level spectra, whose intensities display strong dependence on crystallographic orientation and surface treatment. NH4F-treated Si(111) exhibits almost exclusive monohydride termination which induces a chemical shift of 250 meV relative to the bulk component. On the other hand, 4.5% HF-treated Si(111) and 1% HF-treated Si(100) surfaces show increased dihydride termination with an associated shift of 480 meV. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 2291-2293 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Nanometer-scale Si quantum dots have been spontaneously fabricated on SiO2 by controlling the early stages of low-pressure chemical vapor deposition from pure silane. The tunneling current through Au/1 nm-SiO2/a single Si quantum dot/1 nm-SiO2/n+-Si(100) double-barrier structures has exhibited the clear current bump or negative conductance at 300 K with a peak current to valley ratio as high as 10. © 1997 American Institute of Physics.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Langmuir 6 (1990), S. 334-337 
    ISSN: 1520-5827
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    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 66 (1989), S. 881-884 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Carbonaceous films with high conductivity have been prepared by a pyrolytic chemical-vapor-deposition method using hydrocarbons containing oxygen atoms, phenols, carboxylic acids, etc. The films obtained are self-supporting and flexible. The electrical conductivities of the films depend on the pyrolyzing temperature but not remarkably on the kind of raw materials. The films are converted to high-quality graphitized films with conductivity of 1.6×104 S/cm by heating under an Ar atmosphere to 2800 °C. The electrical conductivity and thermoelectric power of the films are examined as a function of the heat-treatment temperatures. The excellent property of the films obtained in this study seems to arise from the effect of oxygen atoms in the process of condensed aromatic ring formation by pyrolysis.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Histopathology 2 (1978), S. 0 
    ISSN: 1365-2559
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: A case of a 28-month-old boy with chondroectodermal dysplasia (Ellis-van Creveld syndrome) is reported. Besides polydactyly, ectodermal dysplasia, acromelic dwarfism and congenital heart defect, which are characteristic morphologic features of the syndrome, additional dysplastic developmental defects were discovered in the kidneys, liver, and lungs. Detailed histopathologic studies of the growth plates of tibia, femur and ribs disclosed an irregular, partly hyperplastic, partly dystrophic appearance of the epiphyseal cartilage, which was not resorbed properly by the invading blood vessels. Focal areas of necrosis occurred and barriers of tongue-shaped cartilaginous peninsulas persisted. Regular enchondral ossification was hindered and compensatory membrane ossification was found in the fibrosing metaphyseal bone marrow adjacent to the cartilage. Dysplasia and fibrosis of the renal medulla plus interstitial fibrosing nephritis in the cortex resulted in kidney contraction and renal failure. Hepatomegaly, portal fibrosis and bile duct hyperplasia and dysplasia were detected at autopsy, but did not have any clinical significance. These findings once again emphasize that derivatives of all three germ layers are involved in the Ellis-van Creveld syndrome. The possibility that a single metabolic or structural abnormality of the mesenchymal tissues could be responsible for the various organ dysplasias is discussed.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1365-2230
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The activity and gene expression of ornithine decarboxylase (ODC, an indicator of tumour promotion) were induced by the phorbol ester tumour promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), in mouse skin. In the present study, the effect of colchicine, a microtu-bule-disrupting agent, on ODC activity and its gene expression were investigated. On administration of colchicine (100 μg) intraperitoneally 1·5 h before TPA treatment, ODC activity and ODC mRNA levels stimulated by TPA were suppressed to about 52 and 64%, respectively. These results suggest the involvement of a microtubule or colchicine-sensitive substrate in the signal transduction system for gene expression.
    Materialart: Digitale Medien
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