1,182 research outputs found
Orbital Optimization in the Active Space Decomposition Model
We report the derivation and implementation of orbital optimization
algorithms for the active space decomposition (ASD) model, which are extensions
of complete active space self-consistent field (CASSCF) and its
occupation-restricted variants in the conventional multiconfiguration
electronic-structure theory. Orbital rotations between active subspaces are
included in the optimization, which allows us to unambiguously partition the
active space into subspaces, enabling application of ASD to electron and
exciton dynamics in covalently linked chromophores. One- and two-particle
reduced density matrices, which are required for evaluation of orbital gradient
and approximate Hessian elements, are computed from the intermediate tensors in
the ASD energy evaluation. Numerical results on
4-(2-naphthylmethyl)-benzaldehyde and [3]cyclophane and model Hamiltonian
analyses of triplet energy transfer processes in the Closs systems are
presented. Furthermore model Hamiltonians for hole and electron transfer
processes in anti-[2.2](1,4)pentacenophane are studied using an
occupation-restricted variant
Resin composition
The invention relates to an incombustible resin composition produced by blending a compound with a specific ester bond and imide bond in a combustible resin
Green's Function Method for Line Defects and Gapless Modes in Topological Insulators : Beyond Semiclassical Approach
Defects which appear in heterostructure junctions involving topological
insulators are sources of gapless modes governing the low energy properties of
the systems, as recently elucidated by Teo and Kane [Physical Review B82,
115120 (2010)]. A standard approach for the calculation of topological
invariants associated with defects is to deal with the spatial inhomogeneity
raised by defects within a semiclassical approximation. In this paper, we
propose a full quantum formulation for the topological invariants
characterizing line defects in three-dimensional insulators with no symmetry by
using the Green's function method. On the basis of the full quantum treatment,
we demonstrate the existence of a nontrivial topological invariant in the
topological insulator-ferromagnet tri-junction systems, for which a
semiclassical approximation fails to describe the topological phase. Also, our
approach enables us to study effects of electron-electron interactions and
impurity scattering on topological insulators with spatial inhomogeneity which
gives rise to the Axion electrodynamics responses.Comment: 15 pages, 3 figure
Ferroelectricity in the Dion-Jacobson CsBiNbO from first principles
We have studied ferroelectricity in Dion-Jacobson CsBiNbO from first
principles. Using group-theoretical analysis and first-principles density
functional calculations of the total energy and phonons, we perform a
systematic study of the energy surface around a paraelectric prototypic phase.
Our results suggest that CsBiNbO is a ferroelectric with a polarization
of P=40C cm. We propose further experiments to clarify this
point
Out-of-phase oscillation between superfluid and thermal components for a trapped Bose condensate under oscillatory excitation
The vortex nucleation and the emergence of quantum turbulence induced by
oscillating magnetic fields, introduced by Henn E A L, et al. 2009 (Phys. Rev.
A 79, 043619) and Henn E A L, et al. 2009 (Phys. Rev. Lett. 103, 045301), left
a few open questions concerning the basic mechanisms causing those interesting
phenomena. Here, we report the experimental observation of the slosh dynamics
of a magnetically trapped Rb Bose-Einstein condensate (BEC) under the
influence of a time-varying magnetic field. We observed a clear relative
displacement in between the condensed and the thermal fraction center-of-mass.
We have identified this relative counter move as an out-of-phase oscillation
mode, which is able to produce ripples on the condensed/thermal fractions
interface. The out-of-phase mode can be included as a possible mechanism
involved in the vortex nucleation and further evolution when excited by time
dependent magnetic fields.Comment: 5 pages, 5 figures, 25 reference
Fast transform decoding of nonsystematic Reed-Solomon codes
A Reed-Solomon (RS) code is considered to be a special case of a redundant residue polynomial (RRP) code, and a fast transform decoding algorithm to correct both errors and erasures is presented. This decoding scheme is an improvement of the decoding algorithm for the RRP code suggested by Shiozaki and Nishida, and can be realized readily on very large scale integration chips
Photoassociative ionization of Na inside a storage ring
Motivated by recent interest in low dimensional arrays of atoms, we
experimentally investigated the way cold collisional processes are affected by
the geometry of the considered atomic sample. More specifically, we studied the
case of photoassociative ionization (PAI) both in a storage ring where
collision is more unidirectional in character and in a trap with clear
undefinition of collision axis. First, creating a ring shaped trap (atomotron)
we investigated two-color PAI dependence with intensity and polarization of a
probing laser. The intensity dependence of the PAI rate was also measured in a
magneto-optical trap presenting equivalent temperature and density conditions.
Indeed, the results show that in the ring trap, the value of the PAI rate
constant is much lower and does not show evidences of saturation, unlike in the
case of the 3D-MOT. Cold atomic collisions in storage ring may represent new
possibilities for study.Comment: 5 pages, 5 figures; Accepted by Optics Communicatio
Myogenesis in vitro as Seen with the Scanning Electron Microscope
In this paper, we review our recent observations by scanning electron microscopy (SEM) on the differentiation of the cell surface and cytoplasmic organelles in embryonic chick skeletal muscle cells in vitro. The changes of the surface structures of myoblasts during mitosis were essentially similar to those of other cell types, but the characteristic spindle shape of myoblasts did not change throughout most of this period. Cytoskeletal structures under the sarcolemma were examined by Triton extraction and metal coating. Cells in S, G2 and M possessed a dense, and those in G1 a loose filament network under the membrane. Myotubes possessed a dense network under the sarcolemma. In the fusion area between a myoblast and a myotube, the cytoskeletal domain of the former could be distinguished from the latter because of the mosaic appearance of the subsarcolemmal cytoskeletal network. This net-work was composed predominantly of 10-13 nm filaments; they were identified as actin filaments because of their decoration with myosin subfragment-1. Triton treatment and thiocarbohydrazideosmium staining allowed us to visualize myofibrils. They ran in the direction of inferred stress lines brought about by elongation and adhesion of the cells to substrate. Intracellular membranous organelles could be seen by the freeze-polishing and osmium-maceration procedure. Mitochondria exhibited complex irregular branchings. T system tubules ran a tortuous course. Sarcoplasmic reticula with occasional dilatations were connected to each other. The results are of sufficient promise to encourage more extensive analysis of myogenesis by SEM
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