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
    Effects of In profile on material and device properties of AlGaAs/InGaAs/GaAs high electron mobility transistors (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 540-544 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The molecular-beam-epitaxial growth of InxGa1−xAs on GaAs or AlyGa1−yAs leads to a variation of In content with depth, due to In segregation. However, by predepositing In at the beginning of InxGa1−xAs growth, and also thermally removing the excess In at the end, we can produce a layer with the ideal "square'' In profile. We find that the performance of AlyGa1−yAs/InxGa1−xAs/GaAs high electron mobility transistors is most enhanced by the predeposition step alone. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360862
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Osmotic stress and abscisic acid reduce cytosolic calcium activities in roots of Arabidopsis thaliana (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 19 (1996), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Cytosolic Ca2+· ([Ca2+]i, and elongation growth were measured in the roots of Arabidopsis thaliana. Exposure of plant tissues to high NaCl and abscisic acid (ABA) concentrations results in a reduction in the rate of growth, but the mechanism by which growth is inhibited is not understood. Both NaCl and ABA treatments are known to influence [Ca2+]i, and in this study we measured the effects of salinity and ABA on [Ca2+]i in cells from the meristematic region of Arabidopsis roots. The Ca2+-sensitive dye Fura-2 and ratiometric techniques were used to measure [Ca2+]i in cells of the root meristem region. Resting [Ca2+]i was found to be between 100 and 200 μmol m−3 in roots of untreated plants. Resting [Ca2+]i changed in response to changes in the [Ca2+] surrounding growing roots. An increase of external [Ca2+] increased [Ca2+]i; conversely, a decrease of external [Ca2+] decreased [Ca2+]i. Exposure of roots to NaCl caused a rapid reduction of [Ca2+]i, a response that was proportional to the external NaCl concentration. Thus, as the NaCl concentration was increased, [Ca2+]i in root meristematic cells decreased. Root elongation was also inhibited in proportion to the external NaCl concentration, with maximal inhibition occurring at 120 mol m−3 NaCl. The [Ca2+]i of root meristem cells also changed in response to ABA, and the magnitude of the effect of ABA was dependent upon ABA concentration. Treatment with 0.2 mmol m−3 ABA caused a momentary increase in [Ca2+]i followed by a decrease after 15 min, but 10 mmol m−3 ABA caused an immediate decline in [Ca2+]i. There was a strong positive correlation between [Ca2+]i and root elongation rates. Experiments with the ABA-deficient Arabidopsis mutant aba-3 indicated that the reduction in [Ca2+]i brought about by NaCl was unlikely to be mediated via changes in endogenous ABA. Experiments with solutes such as sorbitol, KCl and NaNO3 indicated that the effects of NaCl could be mimicked by other solutes and was not specific for NaCl.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1996.tb00007.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    A STUDY OF SPECIMEN SIZE ON J-R CURVE BEHAVIOUR (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 14 (1991), S. 0 
    Details
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This paper presents results from an experimental programme to study size effects in J-R curves. Results are presented from unloading compliance R curve tests on different sized single edge notch bend specimens of nickel aluminium bronze and compared with previously published R curve data on a Ti3A1-2.5V titanium and an HY 100 steel alloy. The crack growth resistance was measured in terms of the standard fracture resistance J, J corrected for crack growth and the J modified parameter proposed by Ernst. It was observed that following a region of size independence small specimen J-R curves could fall either above or below the large specimen curve. It was found that although the limit to J controlled crack growth could be extended the limit is not unique but dependent on material type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-2695.1991.tb00706.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    RATE-DEPENDENT DEFORMATION AND FRACTURE OF α-TITANIUM (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 14 (1991), S. 0 
    Details
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Aspects of combined rate-dependent deformation and crack growth in α-titanium at room temperature are examined. Results are presented for tests carried out on pre-cracked three point loaded single edge notch bend and compact tension specimens subjected to constant crack opening displacement rates and constant load. Curves of the ratio of the reference stress to the yield stress as a function of the ratio of the plastic displacement to specimen width are found to be different for different rates. The stress difference between continuously loaded curves and curves obtained from load relaxation tests (“relaxed” curves) is found to be similar to uniaxial results. Earlier uniaxial tests show that the “relaxed” curve represents a boundary below which no further creep takes place. The pre-cracked specimen constant load curves cross the “relaxed” curve, even though the contribution from crack growth to the overall deformation is found to be small. Sustained load crack growth is observed to take place under contained yielding conditions and the sustained load resistance curves are found to be different for different reference stresses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-2695.1991.tb00007.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
    THE EFFECT OF STRAIN RATE ON THE TENSILE AND FRACTURE PROPERTIES OF BS 4360 ‘A’ GRADE SHIP STEEL (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 14 (1991), S. 0 
    Details
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract— The results of high rate tensile and compact tension fracture toughness tests conducted on BS 4360 ‘A’ grade ship steel are presented. Tensile results are reported for strain rates within the range 10–2–103/s and fracture toughness values at rates of increase of J integral within the range 103–106 N/mm/s. The tensile properties of upper yield, lower yield and UTS are shown to be linearly dependent on the logarithm of strain rate whilst fracture toughness is shown to decrease with increasing loading rate prior to approaching a minimum value. The decrease in fracture toughness with increasing test rate is shown to be related to a change in the micro-mechanism of fracture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-2695.1991.tb00648.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Gibberellin-like activity in bleeding-sap of root systems ofHelianthus annuus detected by a new dwarf pea epicotyl assay and other methods (1964)
    Springer
    Planta 63 (1964), S. 269-278 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Am Blutungssaft des Wurzelsystems vonHelianthus annuus wurde ein gibberellinartiges Wirkungsvermögen festgestellt. Das Vorhandensein dieser Aktivität wurde mittels eines neubeschriebenen einfachen und empfindlichen Tests an Zwergerbsen-Epikotylen sowie mit dem Gerstenendosperm- und dem Zwergmais-Test entdeckt. Die gibberellinartigen Stoffe haben Säurecharakter und sind in Äthylacetat löslich. IhrR f -Wert wurde papierchromatographisch mit Isopropanol: Ammoniak: Wasser=10∶1∶1 v/v als Laufmittel zu 0,6–0,7 ermittelt. Das Maß der von der Wurzel produzierten gibberellinartigen Aktivität lag bei etwa 0,05 μg GH3-Äquivalenten pro Pflanze und Tag. Andere Hinweise auf eine Gibberellinsynthese in Wurzeln werden besprochen und ferner die Möglichkeit, daß in Sproß und Wurzel eine signifikante Wechselbeziehung hinsichtlich der Produktion und Verwendung anderer Wuchsstoffarten besteht.
    Notes: Summary Gibberellin-like activity was found to be present in bleeding-sap obtained from root systems ofHelianthus annuus. The presence of activity was detected with a newly described simple and sensitive dwarf pea epicotyl assay, and by the barley endosperm and dwarf maize (Zea mays) tests. The gibberellin-like substance, or substances, are acidic and ethyl acetate soluble, having anR f value of 0.6–0.7 in paper chromatography with isopropyl alcohol: ammonia: water (10∶1∶1 v/v). The quantity of gibberellin-like activity produced by the roots was estimated at approximately 0.05 μg GA3-equivalents/plant/day. Other evidence for gibberellin synthesis in roots is discussed, together with the possibility that shoot and root have significant inter-relationships with regard to the production and utilisation of other types of growth hormone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02089315
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    A New Herbicide: 1 : 1′-Ethylene-2 : 2′-Dipyridylium Dibromide (1958)
    [s.l.] : Nature Publishing Group
    Nature 181 (1958), S. 446-447 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] DURING the early spring of 1955, in the course of an investigation at Jealott's Hill Research Station into the herbicidal properties of a series of quaternary ammonium compounds, one chemical showed exceptional activity. This was originally prepared by R. J. Fielden at Blackley by the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/181446a0
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Bad news from the Arctic with signs of dry nitrogen removal (1990)
    [s.l.] : Nature Publishing Group
    Nature 344 (1990), S. 294-295 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/344294a0
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Relative influences of atmospheric chemistry and transport on Arctic ozone trends (1999)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 400 (1999), S. 551-554 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The reduction in the amount of ozone in the atmospheric column over the Arctic region, observed during the 1990s,, resembles the onset of the Antarctic ozone ‘hole’ in the mid-1980s, but the two polar regions differ significantly with respect to the relative contributions of ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/22999
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Stratospheric ozone depletion by CIONO 2 photolysis (1993)
    [s.l.] : Nature Publishing Group
    Nature 365 (1993), S. 37-39 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] High levels of C1ONO2 have been observed in both hemi-spheres at the edges of the polar winter vortex3'4 and inside the Arctic spring vortex5. We show here for two cases that ozone depletion does not cease once C1ONO2 is formed: (1) assuming that at high latitudes (65° N) all the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/365037a0
    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...