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
    Anisotropy of the Vacancy Migration in Ti, Zr and Hf Hexagonal Close-Packed Metals from First Principles (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 129 (Nov. 2007), p. 75-81 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: The vacancy properties in group-IV hexagonal close-packed metals (Ti, Zr andHf) have been investigated by Density Functional Theory (DFT) calculations performed withthe SIESTA code. The migration energies are found to be systematically lower by »0.15 eVwithin the basal plane than out of the basal plane. The electronic origin of this significantcontribution to diffusion anisotropy is evidenced by the analysis of the local electronic densitiesof states and by a comparison with and empirical potential. The average value of the migra-tion energy is in very good agreement with available experimental data in Zr. The activationenergies for self-diffusion obtained assuming a vacancy mechanism are in good agreement withexperiments in Zr and Hf, although slightly too small, but a significant discrepancy is observedin Ti
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.129.75.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Orientation of Interstitials in Clusters in α-Fe: A Comparison between Empirical Potentials (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 129 (Nov. 2007), p. 67-74 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: We have addressed two issues concerning the relative stabilities of various orienta-tions of interstitial clusters in iron by making a comprehensive comparison between four recentempirical potentials. First, we have investigated the effect of finite temperature on the com-petition between clusters made of a few dumbbells oriented along h111i or h110i. We showby quasi-harmonic calculations that h111i clusters have much larger vibrational formation en-tropies and that they are therefore stabilized with respect to h110i clusters at high temperature.Second, we have compared the formation energies of loops with several hundred atoms withBurgers vector 12 h111i or h100i. The 12 h111i loops are found to be always more stable, but theenergy differences with h100i loops depend strongly on the potential
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.129.67.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Effect of C on Vacancy Migration in α-Iron (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 139 (Apr. 2008), p. 157-164 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: Carbon atoms are always present in Fe-based materials, either as impurities even in highpurity samples or as an intrinsic constituent in steels. Density Functional Theory calculations havebeen performed to study the interaction between C atoms and vacancies (V) in α-Fe. We find thatthe formation of VCn complexes is energetically favourable for n ≤ 3, with VC2 being the moststable one. The energy gain corresponding to the clustering reaction VCn-1 + C → VCn dependsmainly on the strength of C-C covalent bonds. The vacancy diffusivity is shown to be significantlymodified by the formation of vacancy-carbon complexes, exhibiting non-Arrhenius behaviour.Effective vacancy diffusion coefficients in α-Fe are calculated as a function of temperature andcarbon content using a simplified thermodynamic model. The results are discussed in detail in thelimiting case of excess of C with respect to vacancies
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.139.157.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Spin-density wave, charge density wave, and polarizabilities of C60 in the Pariser–Parr–Pople model (1993)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 98 (1993), S. 6369-6376 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The Pariser–Parr–Pople Hamiltonian is investigated on a single C60 molecule in the Hartree–Fock approximation. The effect of on-site and two-site electron–electron interactions on the stability of states other than the normal paramagnetic state is studied. In particular (i) a spin-density wave state, with a structure similar to that of the classical ground state of the antiferromagnetic Heisenberg Hamiltonian; and (ii) a charge density wave state which occurs for weakly screened two-site interactions. Linear and nonlinear optical properties are also calculated. With the finite field method and the Møller–Plesset correction in second order, a linear polarizability of 325.5 a.u. and a second hyperpolarizability of 5.87×10−36 esu are found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.464830
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Formation of small single-layer and nested BN cages under electron irradiation of nanotubes and bulk material (1998)
    Springer
    Applied physics 67 (1998), S. 107-111 
    Details
    ISSN: 1432-0630
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: 12 N12, B16N16 and B28N28 octahedra which were predicted to be magic clusters for the BN system from electronic structure calculations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003390050745
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Organisation of carbon and boron nitride layers in mixed nanoparticles and nanotubes synthesised by arc discharge (1999)
    Springer
    Applied physics 68 (1999), S. 301-308 
    Details
    ISSN: 1432-0630
    Keywords: PACS: 81.05.Yp; 82.80.Pv; 85.40.Ux
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: 2 bonds attests for the presence of ordered BN domains and of carbon domains; (ii) the elemental profiles show that BN layers and carbon layers are immiscible with a radial organisation into two to five domains; and (iii) the sets of layers at free surfaces – including the inner surfaces of tubes – are always made of carbon. The origin of this chemical organisation, which is most likely obtained during the growth, is discussed. For the hafnium-boride metallic particles coated by C/BN envelopes, a model based on the solidification from the outside to the inside of isolated liquid-like droplets is proposed: the carbon phase solidifies first according to theoretical phase diagrams, and forms the outer shells. For the tubes, a directional eutectic solidification process is shown to account for the observed C/BN/C sequence, in a vapour–liquid–solid scheme, with an hafnium-rich liquid-like particle at the tip of the tube.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003390050892
    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...