Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Cloudwater chemistry from ten sites in North America (1988)
    s.l. : American Chemical Society
    Environmental science & technology 22 (1988), S. 1018-1026 
    Details
    ISSN: 1520-5851
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/es00174a004
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Rapid, plant-induced weathering in an aggrading experimental ecosystem (1998)
    Springer
    Biogeochemistry 43 (1998), S. 129-155 
    Details
    ISSN: 1573-515X
    Keywords: cations ; denudation ; ecosystems ; nutrient availability ; sustainability ; weathering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract To evaluate whether rates of weathering of primary minerals are underestimated in watershed mass-balance studies that fail to include products of weathering accumulating in plants and in developing soil, changes in the calcium and magnesium content of vegetation and soil fractions were measured in large, monitored lysimeters (sandbox ecosystems) at Hubbard Brook Experimental Forest, New Hampshire. Weathering was evaluated over 4–8 yr in sandboxes planted with red pine (Pinus resinosa Ait.) and kept mostly free of vegetation (nonvegetated). Three mass-balance equations were used that cumulatively include (a) Ca and Mg in precipitation inputs and drainage outputs, (b) accumulation of Ca and Mg in vegetation, and (c) changes in products of weathering in soils. Soil products were evaluated with an extraction process designed to avoid removing ions from primary minerals. Relative to the input-output equation, the estimated rate of weathering increased 2.4 (Ca) and 1.8 (Mg) times when accumulation of Ca and Mg in pine biomass was accounted for, and 8 (Ca) and 23 (Mg) times when changes in soil products were also included. Weathering estimates that included accumulation in vegetation and soil products were 261 (Ca) and 92 (Mg) kg ha-1 yr-1 in the pine sandbox. These rates were 10 (Ca) and 18 (Mg) times higher than the rates in the nonvegetated sandbox, which were not significantly greater than zero. This study raises the possibility that weathering can play a significant role in the release of nutrients available to plants over short periods. Faster rates like this become extremely important where managers are trying to balance nutrients available to plants from precipitation and weathering release with outputs including harvest removals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006065620344
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Inverse melting of metastable Nb–Cr solid solutions (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 2156-2168 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Metastable body-centered-cubic (bcc) Nb–Cr solid solutions were produced by mechanical alloying over a wide concentration range, and investigated by x-ray diffraction, differential thermal analysis, and transmission electron microscopy. For comparison, metastable bcc and amorphous Nb–Cr alloys were fabricated by sputtering. Upon annealing, the solid solutions prepared by mechanical alloying undergo a transformation to an amorphous phase. The vitrification is polymorphous for a composition Nb45Cr55 whereas two-phase mixtures of amorphous and bcc phases are formed for other concentrations, indicating that metastable equilibria between these two phases develop upon heat treatment. These results, combined with a detailed analysis of the thermodynamic functions of the system, reveal that the amorphous phase has a lower enthalpy and entropy than the bcc phase near equiatomic composition. In consequence, the Gibbs-energy curves of bcc and liquid/amorphous Nb45Cr55 phases versus temperature exhibit two points of intersection, i.e., two melting points, with the amorphous phase being thermodynamically more stable than the bcc phase at low temperatures. Inverse melting is thus thermodynamically possible in the Nb–Cr system, so that the metastable crystalline phase would melt upon cooling. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363048
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    In Defense of Symbolic Convergence Theory: A Look at The Theory and Its Criticisms After Two Decades (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Communication theory 4 (1994), S. 0 
    Details
    ISSN: 1468-2885
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Media Resources and Communication Sciences, Journalism , Psychology
    Notes: This paper argues that not only is theory-building often unfashionable, but the spurious assumption that the presence of scholarly disputes signifies the need to abandon theory-building efforts adds to the difficulties of those willing to develop and expand general theories of human communication. We argue that the time is at hand to provide a new response to the published criticism of the symbolic convergence theory (SCT) and its attendant method of fantasy theme analysis (FTA). Since 1977, critics have made a number of charges about the usefulness of the symbolic convergence theory. We have collapsed the more frequently mentioned and argued points into four indictments of SCT: (1) SCT's proponents have not clarified the basic presuppositions that undergird the theory; (2) SCT is Freudian-based and therefore applies only to small group communication; (3) SCT's insights are researcher-dependent not dependent on the theory; (4) SCT is a relabeling of old concepts with ttivial jargon that lacks precision and clarity. This paper explains and refutes each indictment. The paper concludes with a discussion of constructive criticism and the harms resulting from indiscriminate and unjustified criticism on theory building in general.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1468-2885.1994.tb00093.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Structure and Orientation of the Transmembrane Domain of Glycophorin A in Lipid Bilayers (1994)
    s.l. : American Chemical Society
    Biochemistry 33 (1994), S. 6334-6341 
    Details
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/bi00186a037
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Time-of-flight analysis of light pulses with a temporal resolution of 100 ps (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 1721-1724 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: This article describes a new, direct way to measure the time evolution of single light pulses in the subnanosecond region using time-of-flight analysis. The light pulse is coupled into a set of 40 optical fibers of increasing length arranged in an array. The output of the fiber array is imaged onto a fast gated optical imager (gatewidth 100 ps) coupled to a CCD camera (12 bit). The intensified part of the pulse of each fiber corresponds to the intensity of the light pulse at a different time due to the different transmission time of each fiber. Additional, two-dimensional (2D) spatial resolution is possible if image guides are used instead of fibers. The temporal resolution is limited by the gatewidth of the detector. The difference in length between the longest and the shortest fiber determines the total period of time displayed by the system (1 ns). The pulse characteristics of a recently developed short-pulse Raman-excimer laser are analyzed as an example of an application. Laser parameters like pulse length, energy stability, and jitter are measured with the fiber array. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146983
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Determination of concentration depth profiles using total-reflection x-ray fluorescence spectrometry in combination with ion-beam etching (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 2332-2336 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new method for quantitative concentration depth profiling is presented. It combines a sputter-etching technique with ex situ total-reflection x-ray fluorescence analysis. It allows quantitative depth-resolved analysis of alloys consisting of elements with atomic number ≥13. Basic requirements for a high depth resolution are reported. With this method, an experimental depth resolution of 1.4 (±0.4) nm is obtained that is comparable with the best achievable results from other depth profiling methods. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146941
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Concentration-depth profiling using total-reflection x-ray fluorescence spectrometry in combination with ion-beam microsectioning techniques (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 20-23 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new method for the determination of vertical concentration profiles and its application to bilayer diffusion couples are presented. The method combines sputter sectioning techniques with ex situ total-reflection x-ray fluorescence (TXRF) analysis. It allows quantitative depth-resolved analysis of alloys consisting of elements with atomic numbers ≥13, quantitatively and depth resolved. In contrast to other surface sensitive techniques like Auger electron spectrometry or secondary ion mass spectrometry, TXRF offers the advantage of determining the sampling depth with the same instrument, so that no assumptions about sputtering rates or auxiliary measurements are necessary. With this method a depth resolution of 2.5 nm is obtained, which is comparable with the best achievable results from other depth profiling methods. Moreover, an additional TXRF scan in a nondestructive mode of operation makes a mutual comparison with the results of the sectioning technique possible. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145260
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Laser processing of Nb3Al(Ge, Si) high-field superconductors (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 2686-2691 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The laser irradiation process is a promising method for the fabrication of metastable Al5–Nb3Al(Ge,Si) compounds. Thereby Nb-sheathed Nb-25 at. % Al(Ge,Si) microcomposite tapes are prepared by a conventional powder metallurgical method and heat treated by a high-intensity CO2-laser beam. The parameters selected during laser beam irradiation of the composite determine the relative amounts of molten, heat-affected or unreacted material. In order to obtain large overall superconducting currents, it is favorable to melt a large fraction of the microcomposite without melting the surrounding Nb sheath. The cooling rate after laser beam irradiation determines the structure and the formation of metastable phases in the resolidifying material. The sequences of the process are simulated by heat flow calculations, which consider laser power, beam diameter, tape velocity, thickness, and microstructure, as well as heat transfer coefficients. From these calculations we could deduce optimum conditions for the laser treatment, leading to Jc values of 105 A cm−2 at 10 T and 104 A cm−2 at 16 T.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354662
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Amorphization of Ti/Cr multilayer films by solid-state reaction (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 2249-2253 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The solid-state reaction in Ti/Cr multilayered diffusion couples at temperatures between 450 and 650 °C was investigated by x-ray diffraction. It was found that an amorphous phase is formed at a concentration around 55 at. % Cr. The results are in excellent agreement with those obtained from mechanically alloyed powders, and with the corresponding metastable phase diagram calculated by the calculation of phase diagrams method. The observations strongly suggest that inverse melting is possible in the Ti-Cr system at around 55 at. % Cr.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353129
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...