272 research outputs found
Properties of the Ideal Ginzburg-Landau Vortex Lattice
The magnetization curves M(H) for ideal type-II superconductors and the
maximum, minimum, and saddle point magnetic fields of the vortex lattice are
calculated from Ginzburg-Landau theory for the entire ranges of applied
magnetic fields Hc1 <= H < Hc2 or inductions 0 <= B < Hc2 and Ginzburg-Landau
parameters sqrt(1/2) <= kappa <= 1000. Results for the triangular and square
flux-line lattices are compared with the results of the circular cell
approximation. The exact magnetic field B(x,y) and magnetization M(H, kappa)
are compared with often used approximate expressions, some of which deviate
considerably or have limited validity. Useful limiting expressions and
analytical interpolation formulas are presented.Comment: 11 pages, 8 figure
Lattice-relaxation of zeolites
Quantum-chemical cluster calculations as well as solid-state chemical lattice-calculations indicate that zeolitic SiO2- and AlPO4-structures are flexible structures. The structures reflect the subtle balance of electrostatic and covalent interactions. The different electrostatic interactions lower the symmetry of layered AlPO4-structures compared to that of the corresponding SiO2-compounds. The result is a smaller zeolite-channel dimension for the AlPO4-structure compared to that of the corresponding SiO2-network. Deprotonation of the zeolite-lattice leads to large local changes in geometry that changes acidity compared to that predicted for a non-flexible lattice. Changes in lattice vibrational frequencies are consistent with the theoretically predicted relaxation of the zeolite-lattic
Evidence for a second phosphorylation site on eIF-2α from rabbit reticulocytes
AbstractSer 51 in the NH2-terminal sequence of the α-subunit of eukaryotic peptide initiation factor 2 (eIF-2) has been identified as a second phosphorylation site for the heme-controlled eIF-2α kinase from rabbit reticulocytes. Increased phosphorylation of this serine relative to the previously described phosphorylation site (Ser 48) is observed when the kinase reaction is carried out in the presence of the α-subunit of spectrin. A synthetic peptide corresponding to eIF-2α(41–54) is phosphorylated only in Ser 51 by the eIF-2α kinase
Interaction of vortices in superconductors with kappa close to 2^(-1/2)
Using a perturbative approach to the infinitely degenerate Bogomolnyi vortex
state for a superconductor with kappa = 2^(-1/2), T -> T_c, we calculate the
interaction of vortices in a superconductor with kappa close to 2^(-1/2). We
find, numerically and analytically, that depending on the material the
interaction potential between the vortices varies with decreasing kappa from
purely repulsive (as in a type-II superconductor) to purely attractive (as in a
type-I superconductor) in two different ways: either vortices form a bound
state and the distance between them changes gradually from infinity to zero, or
this transition occurs in a discontinuous way as a result of a competition
between minima at infinity and zero. We study the discontinuous transition
between the vortex and Meissner states caused by the non-monotonous vortex
interaction and calculate the corresponding magnetization jump.Comment: v1:original submit v2:changed formate of images (gave problems to
some) v3:corrected fig v4v6 (was -v4v6) orthographic corrections (and
U_lat/int) mismatch v4:more small orthographic corrections v5:converted to
revtex4 and bibTex v6:Renamed images to submit to pr
CoCoS - duurzame ketenconfiguratoes : broeikasemissies tijdens Transport, Koeling en Bewaring van bloemen : vergelijking twee scenario's: chrysanten vanuit Colombia naar Nederland per zeeschip of per vliegtuig
- …