1,638 research outputs found
Domains in Melts of Comb-Coil Diblock Copolymers: Superstrong Segregation Regime
Conditions for the crossover from the strong to the superstrong segregation regime are analyzed for the case of comb-coil diblock copolymers. It is shown that the critical interaction energy between the components required to induce the crossover to the superstrong segregation regime is inversely proportional to mb = 1 + n/m, where n is the degree of polymerization of the side chain and m is the distance between successive grafting points. As a result, the superstrong segregation regime, being rather rare in the case of ordinary block copolymers, has a much better chance to be realized in the case of diblock copolymers with combs grafted to one of the blocks.
Electromagnetic transitions of the helium atom in superstrong magnetic fields
We investigate the electromagnetic transition probabilities for the helium
atom embedded in a superstrong magnetic field taking into account the finite
nuclear mass. We address the regime \gamma=100-10000 a.u. studying several
excited states for each symmetry, i.e. for the magnetic quantum numbers
0,-1,-2,-3, positive and negative z parity and singlet and triplet symmetry.
The oscillator strengths as a function of the magnetic field, and in particular
the influence of the finite nuclear mass on the oscillator strengths are shown
and analyzed.Comment: 10 pages, 8 figure
Relativistic approach to positronium levels in a strong magnetic field
We have investigated the bound states of an electron and positron in
superstrong magnetic fields typical for neutron stars. The complete
relativistic problem of positronium in a strong magnetic field has not been
succesfully solved up to now. In particular, we have studied the positronium
when it moves relativistically across the magnetic field. A number of problems
which deal with the pulsar magnetosphere, as well as the evolution of
protoneutron stars, could be considered as a field for application
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