1,126 research outputs found
The applicability of the catalytic wet-oxidation to CELSS
The wet oxidation catalysis of Au, Pd, Pt, Rh or Ru on a ceramic honeycomb carrier was traced in detail by 16 to 20 repetitive batch tests each. As a result, Pt or Pd on a honeycomb carrier was shown to catalyze complete nitrogen gasification as N2. Though the catalysts which realize both complete nitrogen gasification and complete oxidation could not be found, the Ru+Rh catalyst was found to be most promising. Ru honeycomb catalyzed both nitrification and nitrogen gasification
Long distance synchronization of mobile robots
This paper considers the long distance master-slave and mutual synchronization of unicycle-type mobile robots. The issues that arise when the elements of a robotic network are placed in different locations are addressed, specifically the time-delay induced by the communication channel linking the robots. Experiments between wirelessly controlled mobile robots located in Eindhoven, The Netherlands and Tokyo, Japan demonstrate the applicability of the proposed approach
Microscopic Evidence for Evolution of Superconductivity by Effective Carrier Doping in Boron-doped Diamond:11B-NMR study
We have investigated the superconductivity discovered in boron (B)-doped
diamonds by means of 11B-NMR on heteroepitaxially grown (111) and (100) films.
11B-NMR spectra for all of the films are identified to arise from the
substitutional B(1) site as single occupation and lower symmetric B(2) site
substituted as boron+hydrogen(B+H) complex, respectively. A clear evidence is
presented that the effective carriers introduced by B(1) substitution are
responsible for the superconductivity, whereas the charge neutral B(2) sites
does not offer the carriers effectively. The result is also corroborated by the
density of states deduced by 1/T1T measurement, indicating that the evolution
of superconductivity is driven by the effective carrier introduced by
substitution at B(1) site.Comment: 4 pages, 6 figures, to be published in Phys. Rev. B (Brief report
Direct Observation of Nonequivalent Fermi-Arc States of Opposite Surfaces in Noncentrosymmetric Weyl Semimetal NbP
We have performed high-resolution angle-resolved photoemission spectroscopy
(ARPES) on noncentrosymmetric Weyl semimetal candidate NbP, and determined the
electronic states of both Nb- and P-terminated surfaces corresponding to the
"opposite" surfaces of a polar crystal. We revealed a drastic difference in the
Fermi-surface topology between the opposite surfaces, whereas the Fermi arcs on
both surfaces are likely terminated at the surface projection of the same bulk
Weyl nodes. Comparison of the ARPES data with our first-principles band
calculations suggests notable difference in electronic structure at the
Nb-terminated surface between theory and experiment. The present result opens a
platform for realizing exotic quantum phenomena arising from unusual surface
properties of Weyl semimetals.Comment: 5 pages, 4 figure
A Recursive Method of the Stochastic State Selection for Quantum Spin Systems
In this paper we propose the recursive stochastic state selection method, an
extension of the recently developed stochastic state selection method in Monte
Carlo calculations for quantum spin systems. In this recursive method we use
intermediate states to define probability functions for stochastic state
selections. Then we can diminish variances of samplings when we calculate
expectation values of the powers of the Hamiltonian. In order to show the
improvement we perform numerical calculations of the spin-1/2
anti-ferromagnetic Heisenberg model on the triangular lattice. Examining
results on the ground state of the 21-site system we confide this method in its
effectiveness. We also calculate the lowest and the excited energy eigenvalues
as well as the static structure factor for the 36-site system. The maximum
number of basis states kept in a computer memory for this system is about 3.6 x
10**7. Employing a translationally invariant initial trial state, we evaluate
the lowest energy eigenvalue within 0.5 % of the statistical errors.Comment: 14 pages, 1 figur
Fermiological Interpretation of Superconductivity/Non-superconductivity of FeTe_{1-x}Se_{x} Thin Crystal Determined by Quantum Oscillation Measurement
We have successfully observed quantum oscillation (QO) for FeTe_{1-x}Se_{x}.
QO measurements were performed using non-superconducting and superconducting
thin crystals of FeTe_{0.65}Se_{0.35} fabricated by the scotch-tape method. We
show that the Fermi surfaces (FS) of the non-superconducting crystal are in
good agreement with the rigid band shift model based on electron doping by
excess Fe while that of the superconducting crystal is in good agreement with
the calculated FS with no shift. From the FS comparison of both crystals, we
demonstrate the change of the cross-sectional area of the FS, suggesting that
the suppression of the FS nesting with the vector Q_{s} = (\pi, \pi) due to
excess Fe results in the disappearance of the superconductivity.Comment: 8 pages, 4 figure
Quantum Heisenberg Antiferromagnet: Improved Spin-Wave Theories Versus Exact-Diagonalization Data
We reconsider the results cocerning the extreme-quantum
square-lattice Heisenberg antiferromagnet with frustrating diagonal couplings
( model) drawn from a comparison with exact-diagonalization data. A
combined approach using also some intrinsic features of the self-consistent
spin-wave theory leads to the conclusion that the theory strongly overestimates
the stabilizing role of quantum flutcuations in respect to the N\'{e}el phase
in the extreme-quantum case . On the other hand, the analysis implies
that the N\'{e}el phase remains stable at least up to the limit which is pretty larger than some previous estimates. In addition, it is
argued that the spin-wave ansatz predicts the existence of a finite range
( in the linear spin-wave theory) where the Marshall-Peierls
sigh rule survives the frustrations.Comment: 13 pages, LaTex, 7 figures on reques
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