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  • Springer  (166)
  • Wiley-Blackwell  (43)
  • American Institute of Physics (AIP)  (27)
  • EDP Sciences  (2)
  • 1990-1994  (238)
  • 1965-1969
  • 1935-1939
  • 1992  (238)
  • 1
    ISSN: 1436-5073
    Keywords: nitrofurazone ; 3-methylbenzothiazolin-2-one hydrazone ; 2-thiobarbituric acid ; isonicotinic acid hydrazide ; metol ; spectrophotometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Four simple and sensitive visible spectrophotometric methods (A-D) for the determination of nitrofurazone in bulk samples and pharmaceutical formulations are described. They are based on the formation of colored species by treating either its reduction product with 3-methylbenzothiazolin-2-one hydrazone in the presence of ferric chloride (method A: λmax 600 nm) or its hydrolysis product with thiobarbituric acid (method B: λmax 520 nm, 440 nm) or barbituric acid (method C: λmax 400 nm) or by oxidizing it with excess N-bromosuccinimide and determining the consumed NBS using metol-isonicotinic acid hydrazide (method D: λmax 620 nm).
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 14 (1992), S. 253-260 
    ISSN: 0392-6737
    Keywords: Dielectric thin films
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Polyacrylamide polymer films of thickness 4.15 μm were prepared by isothermal immersion technique. The dielectric capacitance and dielectric loss of the films were studied as functions of frequency and temperature in the range 100 Hz|10 MHz and (300|450)K, respectively. Two dielectric loss peaks were observed in the dielectric loss spectra and were identified as β and α peaks. The β peak was attributed to the reorientation of dipoles and the α-peak was attributed to the deformations accompanied by large changes in the directions or locations of the dipoles.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-203X
    Keywords: Epidermis ; monolayer culture ; morphogenesis ; somatic embryos
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Somatic embroys and subsequent plant regeneration were obtained from isolated leaf epidermis of Gaillardia picta. Abaxial and adaxial epidermal peels (monolayer) from 45 days old aseptic seedlings were isolated and segments measuring 5 mm x 3 mm were cultured on B5 basal medium supplemented with various growth regulators such as naphthaleneacetic acid or indolebutyric acid and benzylaminopurine or kinetin. Within 12 h of culture the epidermal cells showed receding of cytoplasm from the walls. After 48 h of incubation 3 or 4 localized zones, each consisting of 3–8 cells that accumulated cytoplasm and stained densely, were observed. Mitotic divisions occurred in these zones on day 3 of culture and localized masses of callus were observed in 95% of the cultures after 10 days. In another 5 days, the callus differentiated somatic embryos or roots, depending on the growth regulators and their concentration in the medium.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Reaction kinetics and catalysis letters 48 (1992), S. 519-528 
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Кинетика и механизм восстановления таллия(III) пере-кисью водорода исследовали в среде одномолярной пер-хпорной кислоты. Реакция имеет первый порядок по тал-лию (III) и второй порядок по перекиси водорода. На-блюдается отрицательный катализ по отношению к водо-родным и хлоридным ионам. Бромидный ион катализирует реакцию при низких концентрациях. Не наблюдалось ка-кое-либо влияние ионной силы на скорость реакции. Предложен вероятный механизм реакции, откуда вытека-ет следующее уравнение скорости: Скороств=−[T1(III)]/dt=kK[T1(III)][H2O2]2/[H+], где К-константа равновесия комплекса таллия(III) с перекисью водорода и к-константа скорости реакции между комплексом и перекисью водорода. Полученные с помощью ЭВМ величины EA и ΔS# равны 44,8±6,5 кДж/моль и −107,8±22,1 Дж/К·моль, соответственно.
    Notes: Abstract The kinetics and mechanism of reduction of thallium(III) by hydrogen peroxide has been studied in 1.0 mol dm−3 perchloric acid medium. The reaction is first order with respect to thallium(III) and second order with respect to hydrogen peroxide. A negative hydrogen ion and chloride ion catalysis is observed. Bromide ion is found to catalyze the reaction in low concentration. There is no effect of ionic strength on the rate of the reaction. A plausible mechanistic pathway for the reaction is suggested which leads to the following rate law: Rate=−d[T1(III)]/dt=kK[T1(III)][H2O2]2/[H+] where K is the formation constant of the complex between thallium(III) and hydrogen peroxide and k is the rate constant of the reaction between that complex and hydrogen peroxide. The computed values of Ea and ΔS# are 44.8±6.5 kJ mol−1 and −107.8±22.2 JK−1 mol−1, respectively.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 15 (1992), S. 1149-1170 
    ISSN: 0271-2091
    Keywords: Coastal upwelling ; Turbulence energy ; Exchange coefficient ; Roughness length ; Co-ordinate transformation ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A three-dimensional numerical model has been applied to study the impact of freshwater discharge from a river on the coastal circulation in the western Bay of Bengal. The basic dynamical framework of the model follows closely that described by Johns et al.1 for the simulation of coastal upwelling off the east coast of India. Using this model, experiments have been performed to investigate the impact of the freshwater discharge at the location of Godavari river along the east coast of India. A comparison of the model results, with and without the inclusion of river discharge, shows that the river discharge into the western Bay of Bengal suppresses the upwelling near the river mouth. Though there are no detailed observations on the flow structure near the mouth of the Godavari river, the computed results are in qualitative agreement with the observations documented by Rao and Jayaraman2 and Rao,3 who have shown that during monsoon period the upwelling off Godavari estuary is suppressed.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 21 (1992), S. 239-243 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The dependence of the Kβ/Kα ratio on the chemical constitution of the x-ray emitting atom of 3d-shell elements. V, Cr, Mn and Fe, was studied employing a high-resolution Si(Li) detector. A maximum deviation of 9% in the Kβ/Kα ratio for the elements V and Mn is found when compared with their respective compounds. The experimental results are found to be consistent with the theoretical values due to Brunner's model.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 43 (1992), S. 68-71 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Poly(vinylalkohol)-Filme wurden bei unterschiedlichen elektrischen Feldstärken und Temperaturen polarisiert. Die Peaktemperatur der TSDC-Spektren verschob sich mit steigender Polungsfeldstärke und Polungstemperatur zu höheren Werten. Die Aktivierungsenergien und die Relaxationsparameter des Prozesses wurden ermittelt. Auf Grund der Ergebnisse wurde der Ursprung der TSDC der Raumladungspolarisation mit einem geringen von der Dipolorientierung herrührenden Beitrag zugeordnet.
    Notes: Poly(vinyl alcohol) films were polarized at different electrical field strengths and temperatures. The peak temperature of the TSDC spectra shifted to higher values with increasing polarizing field strength and polarizing temperature. The activation energies and relaxation parameters of the process were evaluated. Based on the results, the origin of TSDC was attributed to space charge polarization with some contribution of dipole orientation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Publication Date: 1992-05-01
    Print ISSN: 0026-3672
    Electronic ISSN: 1436-5073
    Topics: Chemistry and Pharmacology
    Published by Springer
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 2179-2184 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: High energy B implantations were performed into n-type GaAs and InP at room temperature in the range of energies from 1 to 5 MeV and fluences from 1011 to 1016 cm−2. The material did not become amorphous for any of the fluences used. Buried layers with resistivities as high as 108 Ω cm and 106 Ω cm were obtained in GaAs and InP, respectively, after heat treatments. The breakdown voltages corresponding to the highest resistivities are 80 and 35 V, respectively, in GaAs and InP. In GaAs, the Rutherford backscattering analysis on the annealed samples showed an aligned yield close to that of a virgin sample, whereas, the yield in InP is more than that of the as-implanted sample.
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 1421-1427 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: This paper deals with the reactive sputtering of titanium in an argon and oxygen mixture. The variation in cathode potential as a function of oxygen partial pressure has been explained in terms of cathode poisoning effects. The titania films deposited during this process have been studied for their structural and optical characteristics. The effect of substrate temperature (from 25 to 400 °C) and annealing (from 250 to 700 °C) on the packing density, refractive index, extinction coefficient, and crystallinity has been investigated. The refractive index varied from 2.24 to 2.46 and extinction coefficient from 2.6 × 10−3 to 10.4× 10−3 at 500 nm as the substrate temperature increased from 25 to 400 °C. The refractive index increased from 2.19 to 2.35 and extinction coefficient changed from 3.2× 10−3 to 11.6 × 10−3 at 500 nm as the annealing temperature was increased from 250 to 700 °C. Anatase and rutile phases have been observed in the films deposited at 400 °C substrate temperature and annealed at 300 °C. The changes in the optical constants at higher substrate temperature have been attributed to an increase in packing density, oxygen content, and crystallinity of the films.
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