6,609 research outputs found
Femoroatsetabulaarse pitsumise kirurgilise ravi kogemused
Viimase kümne aasta jooksul on tõestatud, et femoroatsetabulaarne pitsumine, mis on tingitud puusanapa või reieluupea/ -kaela anatoomilistest muutustest, võib olla peamine tegur puusaliigese artroosi patogeneesis.
Eesti Arst 2009; 88(Lisa3):5
Green's function multiple-scattering theory with a truncated basis set: An Augmented-KKR formalism
Korringa-Kohn-Rostoker (KKR) Green's function, multiple-scattering theory is
an efficient site-centered, electronic-structure technique for addressing an
assembly of scatterers. Wave-functions are expanded in a spherical-wave
basis on each scattering center and indexed up to a maximum orbital and
azimuthal number , while scattering matrices, which
determine spectral properties, are truncated at where phase
shifts are negligible. Historically, is set equal
to ; however, a more proper procedure retains free-electron and
single-site contributions for with set to
zero [Zhang and Butler, Phys. Rev. B {\bf 46}, 7433]. We present a numerically
efficient and accurate \emph{augmented}-KKR Green's function formalism that
solves the KKR secular equations by matrix inversion [ process
with rank ] and includes higher-order contributions via
linear algebra [ process with rank ].
Augmented-KKR yields properly normalized wave-functions, numerically cheaper
basis-set convergence, and a total charge density and electron count that
agrees with Lloyd's formula. For fcc Cu, bcc Fe and L CoPt, we present the
formalism and numerical results for accuracy and for the convergence of the
total energies, Fermi energies, and magnetic moments versus for a
given .Comment: 7 pages, 5 figure
A Model with Propagating Spinons beyond One Dimension
For the model of frustrated spin-1/2 Heisenberg magnet described in A. A.
Nersesyan and A. M. Tsvelik, (Phys. Rev. B{\bf 67}, 024422 (2003)) we calculate
correlation functions of staggered magnetization and dimerization. The model is
formulated as a collection of antiferromagnetic chains weakly coupled by a
frustrated exchange interaction. The calculation done for the case of four
chains demonstrates that these functions do not vanish. Since the correlation
functions in question factorize into a product of correlation functions of
spinon creation and annihilation operators, this constitutes a proof that
spinons in this model propagate in the direction perpendicular to the chains.Comment: revised version to appear in Phys. Rev B., 8 pages, a reference adde
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