468 research outputs found
Re-examination of orbital ordering in LaMnO: Electron-electron and electron-lattice interactions
The interactions between orbitals in neighboring sites are investigated
in LaMnO by taking into account virtual exchange of electrons and phonons.
The spin and orbital ordering temperatures and the spin wave dispersion
relation are calculated. We find that the orbital ordering is mainly caused by
the electronic interactions and that the Jahn-Teller coupling is much smaller
than that reported previously. We propose that the elastic constant shows a
characteristic change at the N{\'e}el temperature by the spin and orbital
coupling and the higher-order Jahn-Teller coupling.Comment: 9 pages, 5 figure
Minimum Supersymmetric Standard Model on the Noncommutative Geometry
We have obtained the supersymmetric extension of spectral triple which
specify a noncommutative geometry(NCG). We assume that the functional space H
constitutes of wave functions of matter fields and their superpartners included
in the minimum supersymmetric standard model(MSSM). We introduce the internal
fluctuations to the Dirac operator on the manifold as well as on the finite
space by elements of the algebra A in the triple. So, we obtain not only the
vector supermultiplets which meditate SU(3)xSU(2)xU(1)_Y gauge degrees of
freedom but also Higgs supermultiplets which appear in MSSM on the same
standpoint. Accoding to the supersymmetric version of the spectral action
principle, we calculate the square of the fluctuated total Dirac operator and
verify that the Seeley-DeWitt coeffients give the correct action of MSSM. We
also verify that the relation between coupling constants of , and
is same as that of SU(5) unification theory
Supersymmetric Yang-Mills Theory on the Noncommutative Geometry
Recently, we found the supersymmetric counterpart of the spectral triple.
When we restrict the representation space to the fermionic functions of matter
fields, the counterpart which we name "the triple" reduces to the original
spectral triple which defines noncommutative geometry. We see that the
fluctuation to the supersymmetric Dirac operator induced by algebra in the
triple generates vector supermultiplet which mediates gauge interaction.
Following the supersymmetric version of spectral action principle, we calculate
the heat kernel expansion of the square of fluctuated Dirac operator and obtain
the correct supersymmetric Yang-Mills action with U(N) gauge symmetry.Comment: arXiv admin note: text overlap with arXiv:1201.344
A survey of T Tauri stars with AKARI toward the Taurus-Auriga region
Aims: We search new T Tauri star (TTS) candidates with the mid-infrared (MIR)
part of the AKARI All-Sky Survey at 9 and 18 um wavelengths. Methods: We used
the point source catalogue (PSC), obtained by the Infrared Camera (IRC) on
board AKARI. We combined the 2MASS PSC and the 3rd version of the USNO CCD
Astrograph Catalogue (UCAC) with the AKARI IRC-PSC, and surveyed 517 known TTSs
over a 1800-square-degree part of the Taurus-Auriga region to find criteria to
extract TTSs. We considered asymptotic giant branch (AGB) stars, post-AGB
stars, Planetary Nebulae (PNe), and galaxies, which have similar MIR colours,
to separate TTSs from these sources. Results: Of the 517 known TTSs, we
detected 133 sources with AKARI. Based on the colour-colour and
colour-magnitude diagrams made from the AKARI, 2MASS, and UCAC surveys, we
propose the criteria to extract TTS candidates from the AKARI All-Sky data. On
the basis of our criteria, we selected 176/14725 AKARI sources as TTS
candidates which are located around the Taurus-Auriga region. Comparing these
sources with SIMBAD, there are 148 previously identified sources including 115
Young Stellar Objects (YSOs), and 28 unidentified sources. Conclusions: Based
on SIMBAD identifications, we take the TTS-identification probability using our
criteria to be ~75 %. We find 28 TTS candidates, of which we expect 21 to be
confirmed once follow-up observations can be obtained. Although the probability
of ~75 % is not so high, it is affected by the completeness of the SIMBAD
database, and we can search for TTSs over the whole sky, over all star forming
regions.Comment: 12 pages, 9 figures, accepted for publication in A&
Global Zero Emission Scenario: Role of Innovative Technologies
AbstractThis study investigated a zero emission scenario with following two originalities compared to various existing studies. One is that we based on A1T society of SRES (Special Report on Emissions Scenario) of IPCC (Intergovernmental Panel on Climate Change) compared to existing studies on those of B1 or B2. The second one is that various innovative and radical technologies were considered and incorporated, such as biomass energy with CCS (BECCS), and advanced nuclear technologies including hydrogen or synfuel production. We applied a global modeling, whose energies, materials, and biomass and foods supply costs were minimized by linear programing with time horizon up to 2150. We found following features of energy supply structure in A1T scenario. Since the electric demand in A1T scenario in 2100 is two times larger than the others, 1) renewable energy which solely produce electricity, nuclear, and fossil energy with CCS (FECCS) especially coal are main sources of electricity, 2) renewable which can supply heat, namely BECCS and geothermal, satisfies the sector, and 3) hydrogen from coal is introduced in transport sector. It can be concluded that the zero emission energy systems with global economic growth will be possible, by development and deployment of ambitious advanced energy technologies
Enzyme engineering of fungal-derived FAD-GDH by circular permutation
The flavin adenine dinucleotide dependent glucose dehydrogenase (FAD-GDH; EC 1.1.5.9) comprises oxidoreductases that catalyze the initial oxidation of glucose and other sugar molecules, using FAD as the primary electron acceptor. FAD-GDH has received attention as biocatalyst for glucose monitoring, especially self-monitoring of blood glucose.
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