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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of complexes of rhodium(I) and iridium(I) with 3,5-pyrazoledicarboxylic acid and their mixed-valence oxidation products (1991)
    s.l. : American Chemical Society
    Inorganic chemistry 30 (1991), S. 4771-4777 
    Details
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ic00025a018
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  • 2
    Electronic Resource
    Electronic Resource
    Increase in nitrous oxide production in soil induced by ammonium and organic carbon (1994)
    Springer
    Biology and fertility of soils 18 (1994), S. 1-6 
    Details
    ISSN: 1432-0789
    Keywords: Ammonium ; Denitrification ; Nitrification ; Nitrous oxide ; Organic carbon ; Acetylene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We observed that soil cores collected in the field containing relatively high NH inf4 sup+ and C substrate levels produced relatively large quantities of N2O. A series of laboratory experiments confirmed that the addition of NH inf4 sup+ and glucose to soil increase N2O production under aerobic conditions. Denitrifying enzyme activity was also increased by the addition of NH inf4 sup+ and glucose. Furthermore, NH inf4 sup+ and glocose additions increased the production of N2O in the presence of C2H2. Therefore, we concluded that denitrification was the most likely source of N2O production. Denitrification was not, however, directly affected by NH inf4 sup+ in anaerobic soil slurries, although the use of C substrate increased. In the presence of a high substrate C concentration, N2O production by denitrifiers may be affected by NO inf3 sup- supplied from NH inf4 sup+ through nitrification. Alternatively, N2O may be produced during mixotrophic and heterotrophic growth of nitrifiers. The results indicated that the NH inf4 sup+ concentration, in addition to NO inf3 sup- , C substrate, and O2 concentrations, is important for predicting N2O production and denitrification under field conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336436
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  • 3
    Electronic Resource
    Electronic Resource
    Mutagens in feces from vegetarians and non-vegetarians
    Amsterdam : Elsevier
    Mutation Research/Environmental Mutagenesis and Related Subjects 85 (1981), S. 1-12 
    Details
    ISSN: 0165-1161
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0165-1161(81)90281-8
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  • 4
    Electronic Resource
    Electronic Resource
    Reaction paths and kinetics of aluminide formation in Al/epitaxial-W(001) model diffusion barrier systems (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 194-203 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Single-crystal bcc W(001) layers, 140 nm thick, were grown on MgO(001) substrates by ultrahigh-vacuum (UHV) magnetron sputter deposition at Ts=600 °C. Al overlayers, 190 nm thick with strong (001) and (011) preferred orientation and an average grain size of 200 nm, were then deposited at Ts=100 °C without breaking vacuum. Changes in bilayer sheet resistance Rs were monitored continuously as a function of time ta and temperature Ta during UHV annealing. In addition, Rutherford backscattering spectroscopy, x-ray diffraction, transmission electron microscopy (TEM), and scanning TEM, in which cross-sectional specimens were analyzed by energy-dispersive x-ray analysis with a 1 nm resolution, were used to follow area-averaged and local interfacial reaction paths as well as microstructural changes as a function of annealing conditions. The initial reaction products were discontinuous regions of monoclinic-structure WAl4 which exhibit a crystallographic relationship with the underlying W layer. bcc WAl12 forms at a later stage and grows conformally to cover both W and WAl4. WAl4 and WAl12 continue to grow, with W being the primary mobile species, until the Al layer is completely consumed. Information from the microchemical and microstructural analyses was used to model the Rs(Ta,ta) results based upon a multielement equivalent circuit approach which accounts for the observed nonplanar nature of the reaction front. Reaction kinetics and activation energies were determined. The results show that the growth of WAl4 is diffusion limited with an activation energy Ea of 3.1 eV while the formation of WAl12 is reaction limited with Ea=3.3 eV. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360651
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  • 5
    Electronic Resource
    Electronic Resource
    Morphology and microstructure of epitaxial Cu(001) films grown by primary ion deposition on Si and Ge substrates (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 6699-6705 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A low-energy, high-brightness, broad beam Cu ion source is used to study the effects of self-ion energy Ei on the deposition of epitaxial Cu films in ultrahigh vacuum. Atomically flat Ge(001) and Si(001) substrates are verified by in situ scanning tunneling microscopy (STM) prior to deposition of 300 nm Cu films with Ei ranging from 20 to 100 eV. Film microstructure, texture, and morphology are characterized using x-ray diffraction ω-rocking curves, pole figure analyses, and STM. Primary ion deposition produces significant improvements in both the surface morphology and mosaic spread of the films: At Ei〉37 eV the surface roughness decreases by nearly a factor of 2 relative to evaporated Cu films, and at Ei(approximately-equal-to)35 eV the mosaic spread of Cu films grown on Si substrates is only (approximately-equal-to)2°, nearly a factor of 2 smaller than that of evaporated Cu. During deposition with Ei(approximately-equal-to)25 eV on Ge substrates, the film coherently relaxes the 10% misfit strain by formation of a tilt boundary which is fourfold symmetric toward 〈111〉. The films have essentially bulk resistivity with ρ=1.9±0.1 μΩ cm at room temperature but the residual resistance at 10 K, ρ0, shows a broad maximum as a function of Ei, e.g., at Ei(approximately-equal-to)30 eV, ρ0=0.5 μΩ cm. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363795
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  • 6
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of a new fluorine-substituted nonionic dinucleoside phosphonate analog. P-Deoxy-P-(difluoromethyl)thymidylyl(3' .fwdarw. 5')thymidine (1988)
    s.l. : American Chemical Society
    The @journal of organic chemistry 53 (1988), S. 3953-3958 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00252a014
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  • 7
    Electronic Resource
    Electronic Resource
    High-flux low-energy ((approximately-equal-to)20 eV) N+2 ion irradiation during TiN deposition by reactive magnetron sputtering: Effects on microstructure and preferred orientation (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 5395-5403 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of the incident ion/metal flux ratio (1≤Ji /JTi≤15), with the N+2 ion energy Ei constant at (approximately-equal-to)20 eV ((approximately-equal-to)10 eV per incident accelerated N), on the microstructure, texture, and stoichiometry of polycrystalline TiN films grown by ultrahigh-vacuum reactive-magnetron sputtering have been investigated. The layers were deposited in pure N2 discharges on thermally oxidized Si(001) substrates at 350 °C. All films were slightly overstoichiometric with a N/Ti ratio of 1.02±0.03 and a lattice constant of 0.4240±0.0005 nm, equal to that of unstrained bulk TiN. Films deposited with Ji/JTi=1 initially exhibit a mixed texture—predominately (111), (002), and (022)—with competitive columnar growth which slowly evolves into a pure (111) texture containing a network of both inter- and intracolumn porosity with an average column size of (approximately-equal-to)50 nm at t=1.6 μm. In contrast, films grown with Ji/JTi≥5 do not exhibit competitive growth. While still columnar, the layers are dense with an essentially complete (002) preferred orientation and an average column size of (approximately-equal-to)55 nm from the earliest observable stages. The normalized x-ray diffraction (002) intensity ratio in thick layers increased from (approximately-equal-to)0 to 1 as Ji/JTi was varied from 1 to ≥5. Both 111 and 001 interplanar spacings remained constant as a function of film thickness for all Ji/JTi. Thus, contrary to previous models, strain is not the dominant factor in controlling the development of preferred orientation in these films. Moreover, once film texture is fully evolved—whether it be (002) or (111)—during deposition, changing Ji/JTi has little effect as preferred orientation becomes controlled by pseudomorphic forces. Film porosity, however, can be abruptly and reversibly switched by increasing or decreasing Ji/JTi. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359720
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  • 8
    Electronic Resource
    Electronic Resource
    Application of power laws to low Reynolds number boundary layers on smooth and rough surfaces (2001)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 13 (2001), S. 3277-3284 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Scaling laws for the overlap region of near-wall turbulent flows are of particular interest to turbulence researchers and engineers. For the mean flow at sufficiently high Reynolds numbers, the classical boundary layer theory proposes a logarithmic law for the overlap region. On the other hand, at low Reynolds numbers, refined measurements and direct numerical simulation results indicate that the log law region becomes negligibly small. Instead, power laws have received increasing attention as an alternative formulation for the overlap region at low Reynolds numbers. In the present study, we use open channel flow measurements to assess the ability of the power laws proposed by Barenblatt [J. Fluid Mech. 248, 513 (1993)] and George and Castillo [Appl. Mech. Rev. 50, 689 (1997)] to describe the overlap region in low Reynolds number boundary layers on smooth and rough surfaces. The skin friction laws derived from the power laws are also used to estimate the friction velocity, which values are then compared to measurements obtained by other reliable techniques. The results indicate that at low Reynolds numbers the power law formulations can model a wider extent of the flow than the classical logarithmic profile. Both Barenblatt's and George and Castillo's power laws give an excellent prediction of the friction velocities for flows over a smooth surface, but only the skin friction law proposed by George and Castillo gives good prediction for the rough wall data. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1410383
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  • 9
    Electronic Resource
    Electronic Resource
    Al/TixW1−x metal/diffusion-barrier bilayers: Interfacial reaction pathways and kinetics during annealing (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 2312-2322 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Polycrystalline bcc TixW1−x layers with mixed 011 and 002 texture were grown on oxidized Si(001) substrates at 600 °C by ultrahigh-vacuum (UHV) magnetron sputter deposition from W and Ti0.33W0.67 targets using both pure Ar and Xe discharges. Ti concentrations in the 100-nm-thick layers were 0, 6, and 33 at. % depending on target composition and sputtering gas. Al overlayers, 190 nm, thick with strong 111 preferred orientation, were then deposited in Ar at 100 °C with and without breaking vacuum. Changes in bilayer sheet resistance Rs were monitored as a function of time ta and temperature Ta during subsequent UHV annealing. Thermal ramping of Al/W and Al/Ti0.06W0.94 bilayers at 3 °C min−1 resulted in large (〉fourfold) increases in Rs at Ta(similar, equals)550 °C, whereas Rs in the Al/Ti0.33W0.67 bilayers did not exhibit a similar increase until (similar, equals)610 °C. Area-averaged and local interfacial reactions and microstructural changes were also followed as a function of annealing conditions. The combined results indicate that Al/W and Al/Ti0.06W0.94 bilayer reactions proceed along a very similar pathway in which monoclinic WAl4 forms first as a discontinuous interfacial phase followed by the nucleation of bcc WAl12 whose growth is limited by the rate of W diffusion, with an activation energy of 2.7 eV, into Al. In contrast, the W diffusion rate during the early stages of Al/Ti0.33W0.67 annealing is significantly higher allowing the formation of a continuous WAl4 interfacial blocking layer which increases the overall activation energy Ea, still limited by W diffusion, to 3.4 eV and strongly inhibits further reaction. We attribute observed increases in WAl4 nucleation and growth rates in interfacial Al/Ti0.33W0.67 to a "vacancy wind" effect associated with the very rapid (Ea=1.7 eV) diffusion of Ti into Al. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.366039
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  • 10
    Electronic Resource
    Electronic Resource
    Aluminide formation in polycrystalline Al/W metal/barrier thin-film bilayers: Reaction paths and kinetics (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 201-209 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Polycrystalline bcc W layers, 110 nm thick with 011 preferred orientation and an average grain size of 40 nm, were grown on amorphous-SiO2/Si(001) substrates by ultrahigh vacuum (UHV) magnetron sputter deposition at Ts=600 °C. Al overlayers, 170 nm thick with strong 111 preferred orientation and an average grain size of 120 nm, were then deposited at Ts=100 °C without breaking vacuum. Changes in bilayer sheet resistance Rs were monitored continuously as a function of time ta and temperature Ta during UHV annealing. In addition, area-averaged and local interfacial reaction paths, as well as microstructural changes as a function of annealing conditions, were determined by x-ray diffraction, Rutherford backscattering spectroscopy, transmission electron microscopy (TEM), and scanning TEM in which compositional distributions in cross-sectional specimens were obtained by energy-dispersive x-ray analysis using a 1 nm diam probe beam. The two tungsten aluminides which form, WAl4 and WAl12, are nucleated essentially immediately with no measurable induction time. WAl4 grains, extensively twinned, increase in size during the initial reaction, then stop growing as competitive growth in the diffusion limited regime favors WAl12. Information from microstructural and microchemical analyses was used to model the Rs(Ta,ta) data in order to determine reaction kinetics and activation energies. The results show that WAl12 growth is limited by W diffusion, with an activation energy of 2.7 eV, to the Al/aluminide interface. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.365798
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