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  • 1985-1989  (9)
  • 1
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of mononuclear and dinuclear bis(2,2'-bipyridine)ruthenium(II) complexes containing sulfur-donor ligands (1989)
    s.l. : American Chemical Society
    Inorganic chemistry 28 (1989), S. 912-920 
    Details
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ic00304a023
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  • 2
    Electronic Resource
    Electronic Resource
    Role of vanadium in organometallic vapor phase epitaxy grown GaAs (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 1772-1774 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electrical and photoluminescent properties of vanadium incorporated into GaAs epitaxial layers from a VO(OC2H5)3 source during organometallic vapor phase epitaxy were examined. The vanadium concentration in the GaAs was controllably varied from 1016 to 1018 atoms cm−3. Deep level transient spectroscopy showed the presence of an electron trap at Ec−0.15 eV which increased in concentration with vanadium content of the epitaxial layers. A maximum value of 8×1015 cm−3 for this trap was obtained. There were no midgap electron traps associated with vanadium. In intentionally Si-doped epitaxial layers, co-doping with vanadium was observed to have no effect in reducing the carrier density when the Si concentration was ≥4×1016 cm−3. The net carrier concentration profiles resulting from 29Si implantation into GaAs containing 1018 cm−3 of total V had sharper tails than for similar implantation into undoped material, indicating the presence of less than 1016 cm−3 V-related acceptors. Photoluminescent spectra exhibited the characteristic V+3 intracenter emission at 0.65–0.75 eV. No other deep level photoluminescence was detected. For a V concentration of 1016 cm−3 only 2.5×1013 cm−3 was electrically active. Over the entire V concentration investigated this impurity was predominantly (≥99%) inactive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.101287
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Surface polygonization on GaAs wafers (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 1468-1471 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Polygonized surface structure produced by furnace annealing GaAs wafers was studied by optical and scanning electron microscopy. The surface structure was revealed by chemically etching wafers which had been implanted with silicon and subjected to a furnace annealing cycle. Cathodoluminescence micrographs demonstrate an absence of impurity segregation to the polygon boundaries. No correlation was found between growth-induced dislocations and the polygonal networks. It is proposed that the surface structure results from a vacancy-condensation process. Related surface effects were observed for rapidly annealed wafers. A correlation between the furnace annealed and rapidly annealed GaAs is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.341819
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  • 4
    Electronic Resource
    Electronic Resource
    Mechanisms of interdiffusion in copper/nickel thin-film couples (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 1147-1155 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Mechanisms of interdiffusion in copper/nickel thin-film couples have been investigated in the temperature interval 573–777 K by in situ measurement of contact resistance, Auger depth profiling (ADP), and transmission electron microscopy. Correlation between evolution of contact resistance and measured Auger concentration profiles has been established and mechanisms incorporating rapid grain boundary diffusion, followed by defect-assisted diffusion into grain interiors (Type B kinetics), are proposed to explain the accelerated reactions observed. A modified Whipple model and two independent methods, based on ADP and contact resistance measurements, are used to calculate grain boundary and intragranular diffusion coefficients, respectively. The calculated grain boundary diffusion coefficient is (0.82 cm2/s) exp(−1.48eV/kT) for nickel in copper, and approximately 4×10−13 cm2/s for copper in nickel at 673 K. An average intragranular diffusion coefficient for nickel in copper is determined to be (2.6×10−6 cm2/s) exp(−1.38 eV/kT) by both methods, whereas ADP data yield a corresponding value of (5.2×10−8 cm2/s) exp(−1.51eV/kT) for copper in nickel. It is concluded that characterization of chemical composition and microstructure, combined with in situ measurement of concomitant electrical properties, provides a reliable description of interdiffusion mechanisms in this system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.336552
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  • 5
    Electronic Resource
    Electronic Resource
    An analysis of dislocation reduction by impurity hardening in the liquid-encapsulated Czochralski growth of 〈111〉 InP (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 58 (1985), S. 4383-4389 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Excessive impurity additions have been widely used to suppress dislocation generation in the liquid-encapsulated Czochralski (LEC) growth of InP. We have analyzed this approach by means of the quasi-steady-state heat transfer/thermal stress model. A strong motivation for the investigation was provided by the recent measurement of the critical resolved shear stress σCRS of InP as a function of temperature in the range 748–948 °K for several Ge and S concentrations. The experimental data were analyzed by the method of least squares via the usually accepted logarithmic dependence of σCRS on reciprocal temperature. The extrapolated values of σCRS exhibit a monotonic increase with impurity addition at temperatures near the melting point. Introducing the σCRS and realistic estimates of other physical properties (thermal diffusivity, thermal expansion coefficient, elastic constants, etc.) in the thermal stress model, the dislocation distribution pattern in a {111} substrate cut from a 〈111〉 boule was constructed. This necessitated a suitable recasting of the formalism that was previously applicable only to the {100} orientation. The computed dislocation contour maps on {111} wafers display sixfold symmetry resembling the "Star of David,'' in overall agreement with etch-pit patterns. InP crystals 2.5 cm in diameter grown in a standard high ambient temperature gradient but containing a large amount of Ge ((approximately-equal-to)1019 cm−3) are predicted and observed to be dislocation-free. On the other hand, in nominally undoped material a large density of defects is forecast, especially at the periphery, in line with the etchpit configuration. Intermediate doping levels (∼1017 cm−3 Ge, ∼1018 cm−3 S) reduce the density in the core but leave the outer edge essentially unaltered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.335528
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of low X-ray doses inSaccharomyces cerevisiae (1987)
    Springer
    Radiation and environmental biophysics 26 (1987), S. 301-312 
    Details
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Summary Three strains ofSaccharomyces cerevisiae with different capacities for repair of radiation damage (RAD, rad18, and rad52) have been tested for their colony forming ability (CFA) and growth rates after application of small X-ray doses from 3.8 mGy to 40 Gy. There was no reproducible increase in CFA observable after application of doses between 3.8 mGy and 4.7 Gy. X-ray doses of 40 Gy causing an inactivation of CFA from 90% to 50%, depending on the repair capacity of the strains used, caused a reduced increase in optical density during 2 h buffer treatment in comparison to unirradiated cells. This reduction however, is reversible as soon as the cells are transferred into nutrient medium. One hour after transfer into growth medium the portions of cells with large buds (G2 and M phase) and cells with small buds (S phase) are drastically different in irradiated cells from those obtained in unirradiated cells. The time necessary for separation of mother and daughter cells is prolonged by X-ray irradiation and the formation of new buds is retarded.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01221976
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  • 7
    Electronic Resource
    Electronic Resource
    Oscillatory heat production in cell free extract from yeast: Batch and infusion experiments (1988)
    Springer
    Journal of thermal analysis and calorimetry 33 (1988), S. 1013-1018 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mikrokalorimetrische Experimente über oszillierende Wärmeerzeugung in stoffwechselndem zellfreiem Hefeextrakt werden beschrieben. Die Zuckersubstrate für die Glykolyse werden nach zwei verschiedenen Methoden zugeführt: (1) einmalige Addition von Trehalose, (b) Kontinuierliche Infusion von Glukose. Erstmalig wird die Kombination von Kalorimetrie und Substratinfusion bei oszillierenden biochemischen Reaktionen beschrieben.
    Abstract: РЕжУМЕ ОпИсАНы МИкРОкАлОРИ МЕтРИЧЕскИЕ ИжМЕРЕН Иь тЕплОты, пЕРИОДИЧЕск И ОБРАжУУЩЕИсь В МЕтАБОлИтНОИ клЕтк Е НЕсВьжАННОгО цИтОп лАжМЕННОгО ЁкстРАктА пЕкАРНых Д РОжжЕИ. сАхАРНыЕ сУБстРАты Дль глИкОл ИжА ВВОДИлИсь ДВУМь Р АжлИЧНыМИ МЕтОДАМИ; А) ОДНОРАжОВ ыМ пРИБАВлЕНИЕМ тРЕгАлОжы И Б) НЕпРЕРы ВНыМ пРИкАлыВАНИЕМ г лУкОжы. ВпЕРВыЕ Дль кОлЕБАтЕ льНых БИОхИМИЧЕскИх РЕАкцИИ сООБЩЕН кОМБ ИНИРОВАННыИ МЕтОД кА лОРИМЕтРИИ И ИНФУжИОННыИ МЕтОД пРИкАлыВАНИь сУБстР АтА.
    Notes: Abstract Microcalorimetric experiments on the periodic heat production in metabolizing cell free cytoplasmic extract from baker's yeast are described. The sugar substrates for glycolysis are supplied by two different techniques: (a) one-time addition of trehalose; (b) continuous infusion of glucose. For the first time the combination of calorimetry and substrate infusion technique is reported for oscillating biochemical reactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01912724
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  • 8
    Electronic Resource
    Electronic Resource
    Numerical method for the resolution of nonlinear heat transfer problems (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Communications in Applied Numerical Methods 4 (1988), S. 17-23 
    Details
    ISSN: 0748-8025
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: We solve a nonlinear heat transfer problem using a general formalism based on the combination of the finite element and the optimal linearization methods. The results are compared with an ‘exact’ numerical iterative solution and the agreement is found to be good.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1630040104
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  • 9
    Electronic Resource
    Electronic Resource
    Numerical analysis of transient states in one-dimensional non-linear systems (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Communications in Applied Numerical Methods 5 (1989), S. 145-152 
    Details
    ISSN: 0748-8025
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An algorithm for the analysis of non-linear partial differential equations describing transient states of one-dimensional physical problems with boundary conditions given on the opposite ends of the analysed domain is presented. The algorithm makes use of the Runge-Kutta and bisection methods used in space ∝1 and the forward finite difference method for the time domain. The algorithm is illustrated by one-dimensional analysis of a temperature field in a transient state.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1630050302
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