6,280 research outputs found

    Power law velocity fluctuations due to inelastic collisions in numerically simulated vibrated bed of powder}

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    Distribution functions of relative velocities among particles in a vibrated bed of powder are studied both numerically and theoretically. In the solid phase where granular particles remain near their local stable states, the probability distribution is Gaussian. On the other hand, in the fluidized phase, where the particles can exchange their positions, the distribution clearly deviates from Gaussian. This is interpreted with two analogies; aggregation processes and soft-to-hard turbulence transition in thermal convection. The non-Gaussian distribution is well-approximated by the t-distribution which is derived theoretically by considering the effect of clustering by inelastic collisions in the former analogy.Comment: 7 pages, using REVTEX (Figures are inculded in text body) %%%Replacement due to rivision (Europhys. Lett., in press)%%

    Single-crystal growth and magnetic properties of the metallic molybdate pyrochlore Sm2Mo2O7

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    We have successfully grown cm3-size single crystals of the metallic-ferromagnet Sm2Mo2O7 by the floating-zone method using an infrared-red image furnace. The growth difficulties and the remedies found using a 2-mirror image furnace are discussed. Magnetization studies along the three crystalline axes of the compound are presented and discussed based on our recent proposal of an ordered spin-ice ground state for this compoun

    AGAINST THE NULL COMPLEMENTIZER ANALYSIS OF JAPANESE RELATIVE CLAUSES

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    In this paper, I argued that relative clauses in Japanese are IPs, contrary to the proposal that they are CPs headed by a null complementizer. I assumed that the lack of CP is responsible for the inapplicability of embedded topicalization in relative clauses and clausal adnominal modifiers in Japanese, and concluded that whenever they have a complementizer, it must be overt. I also showed that null complementizers must be licensed by an adjacent verb or noun, and demonstrated that relative clauses in Japanese do not have a null complementizer, based on the observation that they need not be adjacent to the head noun. Hence, I proposed that NGC is a result of Agree between a nominal element D and the embedded subject. Also, in order to answer the question why NGC is possible under Agree Closest and why it is blocked when a complementizer appears overtly, I referred to an analysis where the optional T-to-D head movement plays an important role. Under this analysis, the head movement feeds the Agree relation, but it is blocked when C is intervening between T and D.ArticleNanzan Linguistics Special Issue. 3(2):185-198 (2008)journal articl

    Perovskite Manganites Hosting Versatile Multiferroic Phases with Symmetric and Antisymmetric Exchange Strictions

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    Complete magnetoelectric (ME) phase diagrams of orthorhombic RRMnO3_{3} with and without magnetic moments on the RR ions have been established. Three kinds of multiferroic ground states, the abab-cycloidal, the bcbc-cycloidal, and the collinear EE-type phases, have been identified by the distinct ME responses. The electric polarization of the EE-type phase dominated by the symmetric spin exchange (bmSicdotbmSjbm{S}_{i} cdot bm{S}_{j}) is more than 10 times as large as that of the bcbc-cycloidal phase dominated by the antisymmetric one (bmSitimesbmSjbm{S}_{i} times bm{S}_{j}), and the ME response is enhanced near the bicritical phase boundary between these multiferroic phases of different origins. These findings will provide an important clue for the development of the magnetically induced multiferroics.Comment: 5 pages, 3 figure

    Quality engineering of a traction alternator by robust design

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    Robust design is an engineering methodology for improving productivity during research and development so that high-quality products can be developed and produced quickly and at low cost. A large electrical company was developing traction alternators for a diesel electrical engine. Customer requirement was to obtain very high efficiency which, in turn, was influenced by several design parameters. The usual approach of the 'design-build-test' cycle was considered time-consuming and costly; it used to take anywhere from 4 months to 1 year before finalizing the product design parameters as it involved physical assembly and also testing. Instead, the authors used Taguchi's parameter design approach. This approach took about 8 weeks to arrive at optimum design parameter values; clearly demonstrating the cutting edge of this methodology over the traditional design-build-test approach. The prototype built and tested accordingly gave satisfactory overall performance, meeting and even exceeding customer requirements

    Electromagnons in the multiferroic state of perovskite manganites with symmetric-exchange striction

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    We have investigated electrically-active magnetic excitations (electromagnons) in perovskite manganites with the EE-type (up-up-down-down) spin structure by terahertz spectroscopy. Eu1−x_{1-x}Yx_xMnO3_3 (0.1≤x≤\le x\le1) and Y1−y_{1-y}Luy_yMnO3_3 (0≤y≤\le y\le1) without magnetic ff-moments, which host collinear sinusoidal, AA-type, cycloidal, and EE-type spin orders, are used to examine the systematics of possible electromagnons. Three-peak structures (23, 35, 45 cm−1^{-1}) of magnetic origin show up in the EE-type phase with little composition (yy) dependence of frequencies, making a contrast with the electromagnons observed in the cycloidal-spin (x≤0.8x\le0.8) phases. One of these electromagnon is ascribed to the zone-edge magnon mode based on the calculated magnon dispersions.Comment: 5 pages, 4 figure

    Electromagnons in the multiferroic state of perovskite manganites with symmetric-exchange striction

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    We have investigated electrically-active magnetic excitations (electromagnons) in perovskite manganites with the EE-type (up-up-down-down) spin structure by terahertz spectroscopy. Eu1−x_{1-x}Yx_xMnO3_3 (0.1≤x≤\le x\le1) and Y1−y_{1-y}Luy_yMnO3_3 (0≤y≤\le y\le1) without magnetic ff-moments, which host collinear sinusoidal, AA-type, cycloidal, and EE-type spin orders, are used to examine the systematics of possible electromagnons. Three-peak structures (23, 35, 45 cm−1^{-1}) of magnetic origin show up in the EE-type phase with little composition (yy) dependence of frequencies, making a contrast with the electromagnons observed in the cycloidal-spin (x≤0.8x\le0.8) phases. One of these electromagnon is ascribed to the zone-edge magnon mode based on the calculated magnon dispersions.Comment: 5 pages, 4 figure
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