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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 52 (1983), S. 281-284 
    ISSN: 1432-1246
    Keywords: Thiodiglycolic acid ; Vinyl chloride ; Flame photometric detector ; Biological monitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A simple and selective method to detect thiodiglycolic acid (TdGA) in urine by flame-photometric-detector (FPD) of gas chromatograph (GC) is described. The detection limit of this method is less than 1 ng without disturbances. Urine from 64 subjects exposed to different air concentration of vinyl chloride (VCM) from 0.3 ppm to more than 100 ppm in three groups and 78 subjects was detected in this way. A comparison of the results of these groups shows significant differences between the control and two exposed groups.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 62 (1982), S. 103-108 
    ISSN: 1432-2242
    Keywords: Pollen plants ; Chromosome counts ; Callus formation ; Embryoid formation ; Plant regeneration ; Rubber-tree
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The yield of pollen embryoids from cultured Hevea anthers was increased 4 fold by optimizing the proportion of ammonium nitrate to potassium nitrate in the dedifferentiation medium. For optimal differentiation of pollen embryoids, kinetin, 2,4-D and α-naphtalene acetic acid are required. Anther culture for 50 days on the dedifferentiation medium is a prerequisite for the selective development of calli and embryoids from microspores. The determination of chromosome numbers in embryoids, plantlets and regenerated trees reveals that they originate from (poly)haploid pollen grains (n=2x=18). Aneuploid, triploid (3x=27) and tetraploid (4x=36) cells were encountered in increasing frequencies as the embryoids and plants developed. A few haploid cells with 9 chromosomes were consistently observed. Buds from shoots with mixoploid chromosome numbers can be grafted and the change in the chromosome constitution of the developing new shoots followed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International journal of infrared and millimeter waves 5 (1984), S. 691-703 
    ISSN: 1572-9559
    Keywords: bandwidth characteristic ; beam-wave interaction ; gyrotron traveling-wave amplifier
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract With a set of equations for the self-consistent large-signal interaction derived in this paper, the bandwidth characteristics of a non-reflection-type gyrotron-TWA using a tapered waveguide and tapered magnetic field system have been analysed. Numerical calculations indicate that under defined conditions an instantaneous bandwidth of nearly 10 % at a center frequency of 35 GHz with a length of the order of only∼8 cm of the rf interaction region could be achieved.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    International journal of infrared and millimeter waves 5 (1984), S. 1117-1127 
    ISSN: 1572-9559
    Keywords: self-consistent large-signal theory ; bandwidth characteristic ; gyrotron traveling-wave amplifier
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A computer-aided design of the wide-band reflection-type gyrotron-TWA is presented in this paper. Using a set of equations for the self-consistent large-signal interaction the bandwidth characteristics of a wide-band reflection-type gyrotron-TWA with both tapered waveguide and tapered magnetic field could be estimated. Computer simulation shows that under defined conditions a 3 dB instantaneous bandwidth of nearly 25 % at a center frequency of 35 GHz with a ∼ 60 cm long rf waveguide could be obtained.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The dielectric and piezoelectric properties (d-p properties) of four kinds of doped lead titanate zirconate piezoelectric ceramics (PZTs) have been measured from 4.2 to 300 K. The d-p properties of the materials converge with decreasing temperature down to liquid helium temperature, even though the properties have large differences at room temperatue. The values of mechanical and electrical quality factors,Q m,Q e, and of the frequency constant,N, of the materials increased at low temperature. It is evident from the freeze out inK′ and the associate temperature: frequency-dependent maxima in tan 5 that the relaxation processes including ferroelectric domain wall motion and thermal defect motion contribute to the d-p properties. The Navy type-III composition has a minimum temperature coefficient of d-p parameters and it is evident that PZT ceramics modified with Fe2O3 can provide good stability and also give the strongest piezoelectric response at liquid helium temperature.
    Type of Medium: Electronic Resource
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