43,837 research outputs found
Effect of distribution of stickers along backbone on temperature-dependent structural properties in associative polymer solutions
Effect of distribution of stickers along the backbone on structural
properties in associating polymer solutions is studied using self-consistent
field lattice model. Only two inhomogeneous morphologies, i.e.,
microfluctuation homogenous (MFH) and micelle morphologies, are observed. If
the system is cooled, the solvent content within the aggregates decreases. When
the spacing of stickers along the backbone is increased the
temperature-dependent range of aggregation in MFH morphology and half-width of
specific heat peak for homogenous solutions-MFH transition increase, and the
symmetry of the peak decreases. However, with increasing spacing of stickers,
the above three corresponding quantities related to micelles behave
differently. It is demonstrated that the broad nature of the observed
transitions can be ascribed to the structural changes which accompany the
replacement of solvents in aggregates by polymer, which is consistent with the
experimental conclusion. It is found that different effect of spacing of
stickers on the two transitions can be interpreted in terms of intrachain and
interchain associations.Comment: 10 pages, 4 figures. arXiv admin note: text overlap with
arXiv:1202.459
Understanding of the Retarded Oxidation Effects in Silicon Nanostructures
In-depth understanding of the retarded oxidation phenomenon observed during
the oxidation of silicon nanostructures is proposed. The wet thermal oxidation
of various silicon nanostructures such as nanobeams, concave/convex nanorings
and nanowires exhibits an extremely different and complex behavior. Such
effects have been investigated by the modeling of the mechanical stress
generated during the oxidation process explaining the retarded regime. The
model describes the oxidation kinetics of silicon nanowires down to a few
nanometers while predicting reasonable and physical stress levels at the
Si/SiO interface by correctly taking into account the relaxation effects
in silicon oxide through plastic flow
Effect of polymer concentration and length of hydrophobic end block on the unimer-micelle transition broadness in amphiphilic ABA symmetric triblock copolymer solutions
The effects of the length of each hydrophobic end block N_{st} and polymer
concentration \bar{\phi}_{P} on the transition broadness in amphiphilic ABA
symmetric triblock copolymer solutions are studied using the self-consistent
field lattice model. When the system is cooled, micelles are observed, i.e.,the
homogenous solution (unimer)-micelle transition occurs. When N_{st} is
increased, at fixed \bar{\phi}_{P}, micelles occur at higher temperature, and
the temperature-dependent range of micellar aggregation and half-width of
specific heat peak for unimer-micelle transition increase monotonously.
Compared with associative polymers, it is found that the magnitude of the
transition broadness is determined by the ratio of hydrophobic to hydrophilic
blocks, instead of chain length. When \bar{\phi}_{P} is decreased, given a
large N_{st}, the temperature-dependent range of micellar aggregation and
half-width of specific heat peak initially decease, and then remain nearly
constant. It is shown that the transition broadness is concerned with the
changes of the relative magnitudes of the eductions of nonstickers and solvents
from micellar cores.Comment: 8 pages, 4 figure
A scheme for demonstration of fractional statistics of anyons in an exactly solvable model
We propose a scheme to demonstrate fractional statistics of anyons in an
exactly solvable lattice model proposed by Kitaev that involves four-body
interactions. The required many-body ground state, as well as the anyon
excitations and their braiding operations, can be conveniently realized through
\textit{dynamic}laser manipulation of cold atoms in an optical lattice. Due to
the perfect localization of anyons in this model, we show that a quantum
circuit with only six qubits is enough for demonstration of the basic braiding
statistics of anyons. This opens up the immediate possibility of
proof-of-principle experiments with trapped ions, photons, or nuclear magnetic
resonance systems.Comment: 4 pages, 3 figure
- …