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
    Investigation of Y1Ba2Cu3O6.9 and Er1Ba2Cu3O6.8 during cyclic temperature variations (1991)
    Springer
    Journal of materials science 26 (1991), S. 545-551 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Gravimetric investigations of the superconductive ceramics Y1Ba2Cu3O6.9, Y1Ba2Cu2.7Al0.3O7.1 and Er1 Ba2Cu3O6.8 during cycling heating ⇄ cooling in the interval 293–1323 K at partial pressure of the oxygen 0.02 and 0.2 × 105 Nm−2 are presented. Intervals of intense weight changes during heating and cooling are determined. Oxygen loss was shown to be the main reason for the weight changes. Structural characteristics and resistivity of the yttrium ceramics in the above-mentioned temperature interval are investigated. Experimental data are discussed within the framework of the models of the quasi-equilibrium and essentially nonequilibrium processes. Binding energy and diffusional parameters of the evolving gas are estimated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00576556
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Strong metal-carrier interaction in cobalt- and nickel-titanium dioxide co-hydrogenation catalysts (1993)
    Springer
    Theoretical and experimental chemistry 28 (1993), S. 176-178 
    Details
    ISSN: 1573-935X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract X-ray photoelectron spectroscopy was used to show that in Co(Ni)-TiO2 catalysts (rutile, anatase) the phenomenon of strong metal-carrier interaction consists of electron interplay between the metal and the carrier (rutile) and partial migration of the oxide onto the metal. This effect was more clearly seen in the rutile samples and accounts for their greater activity and selectivity towards the higher hydrocarbons in CO hydrogenation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00529413
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Quantum-chemical study of the geometric and electronic structure of the chromate anion CrO 4 2− and a chromate group on the surface of finely divided silica by the CNDO/2 method (1989)
    Springer
    Theoretical and experimental chemistry 24 (1989), S. 577-581 
    Details
    ISSN: 1573-935X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A comparative study of the geometric and electronic structure of the chromate anion CrO 4 2− and a chromate group on the surface of finely divided silica (≡Si-O)2-CrO2, which was simulated by a CrO9Si6H12 cluster, has been carried out by the SCF-MO-LCAO method in the all-valence-electron CNDO/2 approximation. The data obtained on the equilibrium geometry of the chromate group attest to the formation of a double bond between the Cr atom and each O atom (which is not bonded to Si). It has been shown that the support has a significant stabilizing influence on the energy of the MO's of the chromate group. The chromate group on an SiO2 surface is characterized by partial delocalization of the frontier MO's among the skeletal bonds; however, the dominant contribution to the HOMO is made by the 2p AO of the oxygen atoms in the coordination shell of the Cr atom (∼70%), and the dominant contribution to the LUMO is made by the 3d AO of the chromium atom (∼50%). The positions and composition of the lowest unoccupied molecular orbitals point out the possibility of the display of electron-acceptor properties by a chromate group on an SiO2 surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00534425
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Conservatism of the KTi2(PO4)3 : Al3+ Phosphate Crystal Lattice (2000)
    Springer
    Theoretical and experimental chemistry 36 (2000), S. 241-253 
    Details
    ISSN: 1573-935X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract We have studied phosphate crystals with low dopant content using X-ray photoelectron spectroscopy (XPS), X-ray fluorescence analysis (XFA), and electron paramagnetic resonance (EPR). We have observed a new stage in the process of doping KTi2(PO4)3 with aluminum: for low aluminum content (n ≤ 0.7 at.%), the aluminum forms a new Al sublattice in the channels of the matrix and essentially does not replace titanium in the main Ti sublattice. It is shown that the anomalous physical and chemical properties of the phosphates are due to a change in the mechanism of dopant distribution in the crystal for small n. We have observed selectivity in the way aluminum occupies different types of voids. The mechanism proposed for the appearance of anomalous properties in the system KTi2(PO4)3–Al2O3–KPO3 can be used in practice for a wide range of oxide framework matrices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005235726939
    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...