Library

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
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 1208-1210 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Corrosion of YBa2Cu3O7−x pellets has been studied using magnetic levitation. Pellets compressed at green compaction pressures of 120–200 MPa were exposed to water and air and the levitation heights were measured over a period of more than a month. A model based on diffusion as a rate-controlling step has been proposed. Levitation height normalized with respect to the initial levitation height was used as the modeling parameter. The experiments indicate that the normalized levitation height decreased with time up to a certain level called the saturation leviation, beyond which there is no change in the levitation height. Samples in air degraded faster than samples in water. The initial period of degradation before saturation fits the proposed model well and therefore appears to be diffusion controlled. The saturation levitation shows a dependence on the green compaction pressure. It has been proposed that corrosion (degrading reactions) is due to open porosities which are closed by the reaction products, thus causing a saturation in the levitation height dependent on the porosities.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 1575-1577 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Shock wave loading produced significant changes in superconductivity in sintered YBa2Cu3O7−δ causing a broad transition with Tc(R=0)∼40 K. The normal-state resistivity increased by 20–50× with the ρ-T curve exhibiting a semiconducting behavior. Comparative thermogravimetric analysis, however, indicated no loss of oxygen (δ∼0.1) in the shock-loaded sample, and x-ray powder diffraction analysis showed no major changes except for slight line broadening. The observed semiconductive behavior and degredation in superconductivity is thus attributed to a rather subtle disturbance in crystal structure, the nature of which is not clearly understood at present. The lack of sufficient recovery in Tc by post-shock oxygen processing at temperatures as high as 750 °C and subsequent cooling implies that the atomic-scale disturbance may not necessarily be related to a simple oxygen disorder. Such defects, if controlled properly, may be advantageously turned into desirable flux-pinning sites for improved critical currents.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1433-075X
    Keywords: Key words Friction stir welding ; Dynamic recrystallization ; Dissimilar metal joining ; Intercalation microstructures ; Extreme plastic flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  Dissimilar plates (0.6 cm thick) of copper and 6061 aluminum alloy; and 2024 aluminum alloy and 6061 aluminum alloy were friction-stir welded at various rotation speeds (400–1200 rpm) and traverse speeds of 1 to 3 mm/s, and produced variations of vortex and other swirl-like intercalations, especially near the weld-zone/work-piece interface. These vortex-like structures are composed of dynamically recrystallized, fine-grained intercalation microstructures which have been observed by optical metallography, scanning electron microscopy and transmission electron microscopy. They are similar to those characterizing mechanical alloying. Such microstructures are especially fascinating because although they resemble vortex instabilities which occur in turbulent fluids, they are formed by extreme deformation in the solid state since centerline temperatures through the weld zone are about 420°C, or ∼0.7 TM in the 6061 aluminum system.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 329 (1987), S. 37-39 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Figure 1 illustrates the development of these explosively (shock-wave) fabricated superconducting monoliths. By 'monolith' we mean a continuous (albeit composite), solid mass. In the context of Fig. 1 this means that the superconducting powder is dynamically compacted and consolidated by an ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 207 (1965), S. 1177-1178 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] IT has been shown previously that plants grown in an electrostatic field of sufficient magnitude have reduced ability to grow, as compared with corresponding control plants which did not experience such potential gradients1. In the investigation to be reported here, similar, but more severe, ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 206 (1965), S. 467-470 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] EXPERIMENTAL investigations of grass plant growth in an electrostatic field over the past two years1?3 have revealed that it is impeded, and in certain cases lethal damage occurs. The electric field damage has been shown to be related to an enzymatic stimulation2, but it has not been defined in ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 200 (1963), S. 490-491 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] It has been previously shown by me3 that plants can be grown in laboratory environments in a manner simulating the natural electric field conditions if the moisture content and electrode configurations are properly maintained. In experiments conducted thus far, seedling orchard grass was planted in ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 201 (1964), S. 1305-1306 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] I RECENTLY1 presented several findings concerning the physiological effects on plant growth of a simulated electric-field environment. It was concluded in this earlier article that a possible mechanism which would explain the effects observed, for example, extensive cell and tissue damage, and a ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Contributions to mineralogy and petrology 45 (1974), S. 251-256 
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract A manganese-bearing mineral characterized by a black hair-like surface crystal growth, and somewhat unique to the Socorro County, New Mexico Area, has been referred to as psilomelane or pseudo-pyrolusite. X-ray diffraction measurements indicated the structure to be the tetragonal (a=4.42 Å, c=2.87Å) MnO2 (pyrolusite) structure; with α-Mn enrichment. Detailed examinations of the mineral specimens made in the scanning and transmission electron microscopes showed the fiber crystals to be pseudo-fluted as a result of an apparent stacking of long needles to form continuous single-crystral bundles oriented along the x-axis These crystals were shown by selected-area electron diffraction to be composed of extended superstructure cells, and these to be commposed of as many as 10 MnO2 unit cells stacked along the x-axis; interrupted by a stacking fault shear of the basic MnO2 lattice resulting in stacking faults. Individual whisker crystals were observed to be terminated by crystallographic facets which is indicative of solution growth expected on considering their geological and mineralogical environment.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    International journal of biometeorology 10 (1966), S. 147-153 
    ISSN: 1432-1254
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Description / Table of Contents: Zusammenfassung Es wurden elektrische Feldbedingungen für optimales Wachstum von Mais eingestellt, die in Feldverzögerungs-Experimenten mit Mais- und Bohnenpflanzen im umgekehrten elektrostatischen Feld, konventionellen elektrostatischen und elektrokinetischen (60 cps) Feld ausgearbeitet worden waren. Uber diese Experimente wurde der kritische dynamische Potentialgradient für Mais- und Bohnenpflanzen erarbeitet, das ist die Feldstärke, die erforderlich ist,um wirklichen Blattschaden zu erzeugen. Er liegt bei ausgedehnter Elektrifizierung ( 〉10 hr)bei ungefähr 100 kv/m. Feldverzögerungs- oder Feldintensitäts-Dauerexperimente mit Mais- und Bohnenpflanzen gestatten die Ausarbeitung der möglichen Beziehungen zwischen Pflanzenwachstum und Gewitter in der natürlichen Umwelt.
    Abstract: Resume On a établi des conditions de champ électriques provoquant une croissance optimum du maïs. Pour ce faire, on s'est basé sur des recherches portant sur les effets de retardement dû au champ tant sur le maïs que sur des pois dans un champ êlectrostatique renversé, conventionnel ou électro-cinétique (60 imp/sec). Ces essais ont permis d'établir un gradient potentiel dynamique critique (champ absolument indispensable pour occasionner des dégâts physiques aux feuilles)et cela pour les deux dites plantes. Ce gradient est voisin de 100 kv/m pour une mise sous tension de longue durée (plus de 10 heures). Des essais de durée de l'intensité du champ ou de son effet retardateur, essais effectués sur du maïs et sur des pois,permettent détablir la relation probable qui existe entre la croissance des plantes et les conditions orageuses naturelles.
    Notes: Abstract Electric field conditions have been regulated for optimum growth of corn as determined from field delay experiments on both corn and bean plants in a reversed electrostatic field, a conventional electrostatic field,and an electrokinetic (60 cps) field. These experiments have established the critical dynamic potential gradient (field strength necessary to induce physical leaf damage)at about 100 kv/m for extended electrification ( 〉10 hr) or corn and bean plants.Field delay or field intensity-time duration experiments on corn and bean plants allow a possible relationship between plant growth and storm conditions in the natural environment to be established.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...