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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 3492-3497 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report our simulation results for the dynamic characteristics of single-transit SiC SiC impact-ionization avalanche transit-time (IMPATT) diodes. An iterative Monte Carlo–Crank-Nicholson technique has been used to solve the coupled electron transport-heat conduction problem. This procedure allows for accurate computation of both the device current as a function of temperature, time, and position, and the internal heat generation. The technique is quite general, has not been used before, and can be applied for the analysis of any power device. Our results show that the internal power generation profile within the SiC IMPATT device can have a very nonuniform axial distribution. The internal heating is seen to significantly degrade the device efficiency and optimum operating frequency. With thermal effects the output current values are lower and the transit time is increased. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 16 (1997), S. 965-967 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Abstracts are not published in this journal
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 14 (1995), S. 1058-1061 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-2932
    Keywords: aluminum toxicity ; decline index ; proxy environmental monitoring
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Wood cores were taken at breast height of mature sugar maple (Acer Saccharum Marsh.) trees of approximately the same age from four sites in Ontario, Canada differing in soil characteristics and general tree health. The soils of two of the sites were acidic (podzols), while the soils of the other two sites were calcareous (brunisols). Selected elemental analyses using Neutron Activation Analysis were conducted on the soils and the xylem wood of the sugar maple trees, and the results were compared relative to tree health. Aluminum in stem xylem was found to be significantly higher in declining trees (mean 7.7 ppm) relative to the healthy trees (mean 4.0) from the acidic sites, where aluminum was freely available in the soil. Soil extractable aluminum was also significantly higher in the soil adjacent to the declining trees (mean 5.10) compared to the healthy trees (mean 3.20). These results show that xylem aluminum contents reflect the increased availability of aluminum in acidifying soils and provide additional evidence that dendrochemistry may be used as a proxy environmental monitoring tool.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-2932
    Keywords: aluminum toxicity ; decline index ; proxy environmental monitoring
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Wood cores were taken at breast height of mature sugar maple (Acer Saccharum Marsh.) trees of approximately the same age from four sites in Ontario, Canada differing in soil characteristics and general tree health. The soils of two of the sites were acidic (podzols), while the soils of the other two sites were calcareous (brunisols). Selected elemental analyses using Neutron Activation Analysis were conducted on the soils and the xylem wood of the sugar maple trees, and the results were compared relative to tree health. Aluminum in stem xylem was found to be significantly higher in declining trees (mean 7.7 ppm) relative to the healthy trees (mean 4.0) from the acidic sites, where aluminum was freely available in the soil. Soil extractable aluminum was also significantly higher in the soil adjacent to the declining trees (mean 5.10) compared to the healthy trees (mean 3.20). These results show that xylem aluminum contents reflect the increased availability of aluminum in acidifying soils and provide additional evidence that dendrochemistry may be used as a proxy environmental monitoring tool.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Aldehydes ; Hydrazino benzene sulfonic acid ; Water analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method has been developed for the analysis of environmentally important aldehydes in rain water. The method is based on the derivatization of the aldehydes with hydrazino benzene sulfonic acid, separation of the hydrazones formed by capillary electrophoresis and UV detection at 280 nm. Derivatization was shown to be complete in 15 min at 50°C. The aldehyde derivatives could be separated from each other and from the excess of reagent using a pH 9 borate buffer as background electrolyte, with an analysis time of less than 6 min. The repeatability was better than 0.5% for the peak mobilities and in the order of 2–5% for the peak areas. Detection limits of 0.8–3 μmol L−1 (0.02–0.2 ppm) were obtained. The method was applied for the determination of formaldehyde and acetaldehyde in rain water samples.
    Type of Medium: Electronic Resource
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