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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 16 (1978), S. 239-246 
    ISSN: 1432-0630
    Keywords: 72.40 ; 73
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Indium oxide films doped with tin (ITO-films) have been hf-sputtered from an 80 at-%In2O3/20 at-%SnO2 target onto glass substrates. The sputter atmosphere contained mainly argon (10−2Torr) with addition of oxygen (0≦p O 2≦2·10−2Torr). The sputtered films aren-conductors. The conductivity and density of charge carriers depend on the oxygen content of the sputter gas. They could be varied by two orders of magnitude. In air or in oxygen atmosphere the films oxidize at the surface and for a certain depth beneath the surface, thus decreasing the conductivity. The Hall mobility of the sputtered films is smaller (≈10 cm2V−1 s−1) than one observes at ITO films produced by CVD sparaying or other methods. The conductivity of as sputtered films approached maximum values of about 1000Ώ−1cm−1.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 16 (1978), S. 381-390 
    ISSN: 1432-0630
    Keywords: 73 ; 72.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Indium-tin-oxide films (ITO films) sputtered in Ar-atmosphere with and without addition of oxygen reveal an irreversible increase in conductivity during annealing in vacuum. This annealing process increases drastically the density of free electrons, while the Hall mobility changes only slightly. Below the annealing temperature the temperature dependence of the conductivity is reversible. In films with low density of free electrons, which behave like non-degenerated semiconductors, two activation energies for the mobility could be found. The irreversible changes, observed during annealing in the vacuum, are explained by diffusion of oxygen from the interior of the film to the surface, followed by desorption of the oxygen from the surface into the vacuum. The excess oxygen in the non-stoichiometric films plays the role of electron traps. The irreversible effects during annealing in the vacuum are partly reversible in the long run. If the annealed films are exposed to oxygen or air their conductivity decreases because of diffusion of oxygen from the surface into the film.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 14 (1993), S. 395-403 
    ISSN: 0197-8462
    Keywords: coherence time ; microwave ; amplitude modulation ; ornithine decarboxylase ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Previously, we demonstrated the requirement for a minimum coherence time of an applied, small amplitude (10 μT) ELF magnetic field if the field were to produce an enhancement of ornithine decarboxylase activity in L929 fibroblasts. Further investigation has revealed a remarkably similar coherence time phenomenon for enhancement of ornithine decarboxylase activity by amplitude-modulated 915 MHz microwaves of large amplitude (SAR 2.5 W/kg). Microwave fields modulated at 55, 60, or 65 Hz approximately doubled ornithine decarboxylase activity after 8 h. Switching modulation frequencies from 55 to 65 Hz at coherence times of 1.0 s or less abolished enhancement, while times of 10 s or longer provided full enhancement. Our results show that the microwave coherence effects are remarkably similar to those observed with ELF fields. © 1993 Wiley-Liss. Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 18 (1997), S. 422-430 
    ISSN: 0197-8462
    Keywords: cellular phones ; EMFs ; biological effects ; amplitude modulation ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: We have previously demonstrated that microwave fields, amplitude modulated (AM) by an extremely low-frequency (ELF) sine wave, can induce a nearly twofold enhancement in the activity of ornithine decarboxylase (ODC) in L929 cells at SAR levels of the order of 2.5 W/kg. Similar, although less pronounced, effects were also observed from exposure to a typical digital cellular phone test signal of the same power level, burst modulated at 50 Hz. We have also shown that ODC enhancement in L929 cells produced by exposure to ELF fields can be inhibited by superposition of ELF noise. In the present study, we explore the possibility that similar inhibition techniques can be used to suppress the microwave response. We concurrently exposed L929 cells to 60 Hz AM microwave fields or a 50 Hz burst-modulated DAMPS (Digital Advanced Mobile Phone System) digital cellular phone field at levels known to produce ODC enhancement, together with band-limited 30-100 Hz ELF noise with root mean square amplitude of up to 10 μT. All exposures were carried out for 8 h, which was previously found to yield the peak microwave response. In both cases, the ODC enhancement was found to decrease exponentially as a function of the noise root mean square amplitude. With 60 Hz AM microwaves, complete inhibition was obtained with noise levels at or above 2 μT. With the DAMPS digital cellular phone signal, complete inhibition occurred with noise levels at or above 5 μT. These results suggest a possible practical means to inhibit biological effects from exposure to both ELF and microwave fields. Bioelectromagnetics 18:422-430, 1997. © 1997 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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