11,895 research outputs found
Mean Field Theoretical Structure of He and Be Isotopes
The structures of He and Be even-even isotopes are investigated using an
axially symmetric Hartree-Fock approach with a Skyrme-IIIls mean field
potential. In these simple HF calculations, He and Be isotopes appear to be
prolate in their ground states and Be isotopes have oblate shape isomeric
states. It is also shown that there exists a level crossing when the nuclear
shape changes from the prolate state to the oblate state. The single neutron
levels of Be isotopes exhibit a neutron magic number 6 instead of 8 and show
that the level inversion between 1/2- and 1/2+ levels occurs only for a largely
deformed isotope. Protons are bound stronger in the isotope with more neutrons
while neutron levels are somewhat insensitive to the number of neutrons and
thus the nuclear size and also the neutron skin become larger as the neutron
number increases. In these simple calculations with Skyrme-IIIls interaction no
system with a clear indication of neutron halo was found among He and Be
isotopes. Instead of it we have found 8He+2n, 2n+8He+2n, and 16Be+2n like chain
structures with clusters of two correlated neutrons. It is also shown that 8He
and 14Be in their ground states are below the neutron drip line in which all
nucleons are bound with negative energy and that 16Be in its ground state is
beyond the neutron drip line with two neutrons in positive energy levels.Comment: CM energy correction, 1 figure and more discussions adde
Higgs bosons of a supersymmetric model at the ILC
We study the scalar Higgs sector of the next-to-minimal supersymmetric
standard model with an extra U(1), which has two Higgs doublets and a Higgs
singlet, in the light leptophobic scenario where the extra neutral gauge
boson does not couple to charged leptons. In this model, we find that the
sum of the squared coupling coefficients of the three neutral scalar Higgs
bosons to , normalized by the corresponding SM coupling coefficient is
noticeably smaller than unity, due to the effect of the extra U(1), for a
reasonable parameter space of the model, whereas it is unity in the
next-to-minimal supersymmetric standard model. Thus, these two models may be
distinguished if the coupling coefficients of neutral scalar Higgs bosons to
are measured at the future International Linear Collider by producing them
via the Higgs-strahlung, fusion, and fusion processes.Comment: 12 pages, 2 figures, 1 table, PR
Land use survey and mapping and water resources investigation in Korea
The author has identified the following significant results. Land use imagery is applicable to land use classification for small scale land use mapping less than 1:250,000. Land use mapping by satellite is more efficient and more cost-effective than land use mapping from conventional medium altitude aerial photographs. Six categories of level 1 land use classification are recognizable from MSS imagery. A hydrogeomorphological study of the Han River basin indicates that band 7 is useful for recognizing the soil and the weathering part of bed rock. The morphological change of the main river is accurately recognized and the drainage system in the area observed is easily classified because of the more or less simple rock type. Although the direct hydrological characteristics are not obtained from the MSS imagery, the indirect information such as the permeability of the soil and the vegetation cover, is helpful in interpreting the hydrological aspects
Two non-commutative parameters and regular cosmological phase transition in the semi-classical dilaton cosmology
We study cosmological phase transitions from modified equations of motion by
introducing two non-commutative parameters in the Poisson brackets, which
describes the initial- and future-singularity-free phase transition in the
soluble semi-classical dilaton gravity with a non-vanishing cosmological
constant. Accelerated expansion and decelerated expansion corresponding to the
FRW phase appear alternatively, and then it ends up with the second accelerated
expansion. The final stage of the universe approaches the flat spacetime
independent of the initial state of the curvature scalar as long as the product
of the two non-commutative parameters is less than one. Finally, we show that
the initial-singularity-free condition is related to the second accelerated
expansion of the universe.Comment: 13 pages, 4 figures; v2. to appear in Mod. Phys. Lett.
Generic Bell inequalities for multipartite arbitrary dimensional systems
We present generic Bell inequalities for multipartite multi-dimensional
systems. The inequalities that any local realistic theories must obey are
violated by quantum mechanics for even-dimensional multipartite systems. A
large set of variants are shown to naturally emerge from the generic Bell
inequalities. We discuss particular variants of Bell inequalities, that are
violated for all the systems including odd-dimensional systems.Comment: Accepted in Phys. Rev. Let
Exactly Soluble Quantum Wormhole in Two Dimensions
We are presenting a quantum traversable wormhole in an exactly soluble
two-dimensional model. This is different from previous works since the exotic
negative energy that supports the wormhole is generated from the quantization
of classical energy-momentum tensors. This explicit illustration shows the
quantum-mechanical energy can be used as a candidate for the exotic source. As
for the traversability, after a particle travels through the wormhole, the
static initial wormhole geometry gets a back reaction which spoils the wormhole
structure. However, it may still maintain the initial structure along with the
appropriate boundary condition.Comment: v1. 13 pages, 1 figure, REVTeX3; v2. 1 Ref. added, REVTeX4, to appear
in Phys. Rev.
Electronic and Magnetic Properties of Partially-Open Carbon Nanotubes
On the basis of the spin-polarized density functional theory calculations, we
demonstrate that partially-open carbon nanotubes (CNTs) observed in recent
experiments have rich electronic and magnetic properties which depend on the
degree of the opening. A partially-open armchair CNT is converted from a metal
to a semiconductor, and then to a spin-polarized semiconductor by increasing
the length of the opening on the wall. Spin-polarized states become
increasingly more stable than nonmagnetic states as the length of the opening
is further increased. In addition, external electric fields or chemical
modifications are usable to control the electronic and magnetic properties of
the system. We show that half-metallicity may be achieved and the spin current
may be controlled by external electric fields or by asymmetric
functionalization of the edges of the opening. Our findings suggest that
partially-open CNTs may offer unique opportunities for the future development
of nanoscale electronics and spintronics.Comment: 6 figures, to appear in J. Am. Chem. So
Electroweak phase transition in a nonminimal supersymmetric model
The Higgs potential of the minimal nonminimal supersymmetric standard model
(MNMSSM) is investigated within the context of electroweak phase transition. We
investigate the allowed parameter space yielding correct electroweak phase
transitoin employing a high temperature approximation. We devote to
phenomenological consequences for the Higgs sector of the MNMSSM for
electron-positron colliders. It is observed that a future linear
collider with GeV will be able to test the model with regard
to electroweak baryogenesis.Comment: 28 pages, 5 tables, 12 figure
A Most Unusual Zeolite Templating: Cage to Cage Connection of One Guest Molecule
An unusual case of a diquaternary ammonium dication, with large bulky end groups built from the tropane moiety and connected by a C4 methylene chain, is found to reside in zeolite SSZ-35 (STF). The structure of the guest/host product is such that the tropane bicylic entities reside in the shallow cavities of the cages of the STF structure and the C4 methylene chain runs through the 10-ring (~5.5 Ã…) window that connects the cages. This is a most unusual (and energy-intensive) templating of a zeolite structure with the guest molecule spanning two unit cells. The unusual result was found by single crystal studies with the addition of the use of the SQUEEZE program to show a consistent fit for the guest molecule following from measured electron densities in the crystal structure work. These analyses were followed with MAS NMR studies to confirm the integrity of the diquaternary guest molecule in the host sieve. A few comparative diquaternary guest molecules in MFI zeolite are also studied
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