1,693 research outputs found
Hamiltonian Reduction and Topological Conformal Algebra in Non-critical Strings
We study the hamiltonian reduction of affine Lie superalgebra
. Based on a scalar Lax operator formalism, we derive the free
field realization of the classical topological topological algebra which
appears in the non-critical strings. In the quantum case, we analyze
the BRST cohomology to get the quantum free field expression of the algebra.Comment: 13 pages Latex, UTHEP-26
Lie Superalgebra and Extended Topological Conformal Symmetry in Non-critical Strings
We obtain a new free field realization of super algebra using
the technique of quantum hamiltonian reduction. The construction is based on a
particular choice of the simple root system of the affine Lie superalgebra
associated with a non-standard embedding. After
twisting and a similarity transformation, this algebra can be identified as
the extended topological conformal algebra of non-critical string
theory.Comment: 14pages, UTHEP-27
Chemical Reaction between Single Hydrogen Atom and Graphene
We study chemical reaction between a single hydrogen atom and a graphene,
which is the elemental reaction between hydrogen and graphitic carbon
materials. In the present work, classical molecular dynamics simulation is used
with modified Brenner's empirical bond order potential. The three reactions,
that is, absorption reaction, reflection reaction and penetration reaction, are
observed in our simulation. Reaction rates depend on the incident energy of the
hydrogen atom and the graphene temperature. The dependence can be explained by
the following mechanisms: (1) The hydrogen atom receives repulsive force by
pi-electrons in addition to nuclear repulsion. (2) Absorbing the hydrogen atom,
the graphene transforms its structure to the ``overhang'' configuration such as
sp-3 state. (3) The hexagonal hole of the graphene is expanded during the
penetration of the hydrogen atom.Comment: 10 pages, 9 figures. This paper was submitted to PR
Incident angle dependence of reactions between graphene and hydrogen atom by molecular dynamics simulation
Incident angle dependence of reactions between graphene and hydrogen atoms
are obtained qualitatively by classical molecular dynamics simulation under the
NVE condition with modified Brenner reactive empirical bond order (REBO)
potential. Chemical reaction depends on two parameters, i.e., polar angle
and azimuthal angle of the incident hydrogen. From the
simulation results, it is found that the reaction rates strongly depend on
polar angle . Reflection rate becomes larger with increasing ,
and the dependence of adsorption rate is also found. The
dependence is caused by three dimensional structure of the small potential
barrier which covers adsorption sites. dependence of penetration rate is
also found for large .Comment: 4 pages, 7 figure
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