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Search Results: 1 - 10 of 151824 matches for " H. Yoshida "
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Predicting amplitude of solar cycle 24 based on a new precursor method
A. Yoshida ,H. Yamagishi
Annales Geophysicae (ANGEO) , 2010,
Abstract: It is shown that the monthly smoothed sunspot number (SSN) or its rate of decrease during the final years of a solar cycle is correlated with the amplitude of the succeeding cycle. Based on this relationship, the amplitude of solar cycle 24 is predicted to be 84.5±23.9, assuming that the monthly smoothed SSN reached its minimum in December 2008. It is further shown that the monthly SSN in the three-year period from 2006 through 2008 is well correlated with the monthly average of the intensity of the interplanetary magnetic field (IMF). This correlation indicates that the SSN in the final years of a solar cycle is a good proxy for the IMF, which is understood to reflect the magnetic field in the corona of the sun, and the IMF is expected to be smallest at the solar minimum. We believe that this finding illuminates a physical meaning underlying the well-known precursor method for forecasting the amplitude of the next solar cycle using the aa index at the solar minimum or its average value in the decaying phase of the solar cycle (e.g. Ohl, 1966), since it is known that the geomagnetic disturbance depends strongly on the intensity of the IMF. That is, the old empirical method is considered to be based on the fact that the intensity of the coronal magnetic field decreases in the late phase of a solar cycle in parallel with the SSN. It seems that the precursor method proposed by Schatten et al. (1978) and Svalgaard et al. (2005), which uses the intensity of the polar magnetic field of the sun several years before a solar minimum, is also based on the same physical phenomenon, but seen from a different angle.
Longitudinal and Transverse Spin Responses in Relativistic Many Body Theory
K. Yoshida,H. Toki
Physics , 1998, DOI: 10.1016/S0375-9474(99)00018-4
Abstract: Spin longitudinal and transverse response function are studied by means of the relativistic many-body theory. The spin response functions in the relativistic theory are largely reduced from those in the non-relativistic theory. The local density approximation with the eikonal approximation is applied to the the nuclear absorption in the $(\vec{p},\vec{n})$ reactions on C and Ca. We compare the calculated results with the recent experimental data.
Phase Diagram and Spin Dynamics in Volborthite with a Distorted Kagome Lattice
M. Yoshida,M. Takigawa,H. Yoshida,Y. Okamoto,Z. Hiroi
Physics , 2009, DOI: 10.1103/PhysRevLett.103.077207
Abstract: We report 51V-NMR study on a high-quality powder sample of volborthite Cu3V2O7(OH)2/2H2O, a spin-1/2 Heisenberg antiferromagnet on a distorted kagome lattice formed by isosceles triangles. In the magnetic fields below 4.5 T, a sharp peak in the nuclear spin-lattice relaxation rate 1/T1 accompanied with line broadening revealed a magnetic transition near 1 K. The low temperature phase shows anomalies such as a Lorentzian line shape, a 1/T1 propto T behavior indicating dense low energy excitations, and a large spin-echo decay rate 1/T2 pointing to unusually slow fluctuations. Another magnetic phase appears above 4.5 T with less anomalous spectral shape and dynamics.
Heterogeneous spin state in the field-induced phase of volborthite as seen via 51V nuclear magnetic resonance
M. Yoshida,M. Takigawa,H. Yoshida,Y. Okamoto,Z. Hiroi
Physics , 2011, DOI: 10.1103/PhysRevB.84.020410
Abstract: We report results of 51V NMR in the field-induced phase of volborthite Cu3V2O7(OH)dot2H2O, a spin-1/2 antiferromagnet on a distorted kagome lattice. In magnetic fields above 4.5 T, two types of V sites with different spin-echo decay rates are observed. The hyperfine field at the fast decaying sites has a distribution, while it is more homogeneous at the slowly decaying sites. Our results indicate a heterogeneous state consisting of two spatially alternating Cu spin systems, one of which exhibits anomalous spin fluctuations contrasting with the other showing a conventional static order.
A Rapid and Ecofriendly Treatment Technique for Rice Bran Oil Stabilization and Extraction under Sub-critical Water Condition
O. Pourali,F. Salak Asghari,H. Yoshida
Lecture Notes in Engineering and Computer Science , 2009,
Application of Subcritical Water Treatment for Production of Phenolic Compounds from Rice Bran Biomass
F. Salak,O. Pourali,H. Yoshida
Lecture Notes in Engineering and Computer Science , 2009,
Ferromagnetism and Curie temperature of Vanadium-doped Nitrides
V. A. Dinh,H. Katayama-Yoshida
Physics , 2005,
Abstract: Electronic structures, exchange interaction mechanism between magnetic ions and Curie temperature of Vanadium - doped Nitrides (AlN, GaN, and InN) are studied within KKR-LSDA-CPA. It is found that the ferromagnetic super-exchange interaction mechanism is dominant at low concentrations of Vanadium, but the anti-ferromagnetic super-exchange interaction appears and reduces the stabilization of ferromagnetism at sufficiently high concentrations (x > 0.10), especially for Vanadium-doped AlN and Vanadium- doped GaN. The estimation of the Curie temperature within the mean field approximation shows the Curie temperature of Vanadium-doped Nitrides exceeding the room temperature with a few constituents of Vanadium.
Representing Euclidean quantum fields as scaling limit of particle systems
S. Albeverio,H. Gottschalk,M. -w. Yoshida
Mathematics , 2005,
Abstract: We give a new representation of Euclidean quantum fields as scaling limits of systems of interacting, continuous, classical particles in the grand canonical ensemble.
Systems of classical particles in the grand canonical ensemble, scaling limits and quantum field theory
S. Albeverio,H. Gottschalk,M. W. Yoshida
Mathematics , 2006, DOI: 10.1142/S0129055X05002327
Abstract: Euclidean quantum fields obtained as solutions of stochastic partial pseudo differential equations driven by a Poisson white noise have paths given by locally integrable functions. This makes it possible to define a class of ultra-violet finite local interactions for these models (in any space-time dimension). The corresponding interacting Euclidean quantum fields can be identified with systems of classical "charged" particles in the grand canonical ensemble with an interaction given by a nonlinear energy density of the "static field" generated by the particles' charges via a "generalized Poisson equation". The infinite volume limit of such systems is discussed for models with trigonometric interactions using a representation of such models as Widom-Rowlinson models associated with a (formal) Potts models at imaginary temperature. The continuum limit of the particle systems under consideration is also investigated and the formal analogy with the scaling limit of renormalization group theory is pointed out. In some simple cases the question of (non-) triviality of the continuum limits is clarified.
Nitroxide-Mediated Photo-Controlled/Living Radical Polymerization of Methacrylic Acid  [PDF]
Eri Yoshida
Open Journal of Polymer Chemistry (OJPChem) , 2013, DOI: 10.4236/ojpchem.2013.31004

The photo-controlled/living radical polymerization of methacrylic acid (MAA) was performed at room temperature by irradiation with a high-pressure mercury lamp using azo initiators and 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl as the mediator in the presence of (4-tert-butylphenyl)diphenylsulfonium triflate (tBuS) as the accelerator. Whereas the bulk polymerization yielded polymers with a bimodal molecular weight distribution in both the absence and presence of tBuS, the solution polymerization in methanol produced unimodal polymers with the molecular weight distribution of 2.0 - 2.3 in the presence of tBuS. The molecular weight distribution of the resulting poly (MAA) decreased with an in- crease in tBuS. The dilution of the monomer concentration also reduced the molecular weight distribution. The use of the initiator with a low 10-h half-life temperature also effectively controlled the molecular weight. The livingness of the polymerization was confirmed by obtaining linear increases in the first-order conversion versus time, the molecular weight versus the conversion, and the molecular weight versus the reciprocal of the initiator concentration.

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