^{75}As NMR study of the growth of paramagnetic-metal domains due to electron doping near the superconducting phase in LaFeAsO_{1-x}F_{x}

We studied the electric and magnetic behavior near the phase boundary between antiferromagnetic (AF) and superconducting (SC) phases for a prototype of high-T_c pnictides LaFeAsO_{1-x}F_{x} by using nuclear magnetic resonance, and found that paramagnetic-metal (PM) domains segregate from AF domains. PM domains grow in size with increasing electron doping level and are accompanied by the onset of superconductivity, and thus application of pressure or increasing the doping level causes superconductivity. The existence of PM domains cannot be explained by the existing paradigm that focuses only on the relationship between superconductivity and antiferromagnetism. Based on orbital fluctuation theory, the existence of PM domains is evidence of the ferroquadrupole state.Comment: 5 figure

Influence of lamination orientation and stacking on magnetic characteristics of grain-oriented silicon steel laminations

Analytical and experimental investigations have been carried out upon the behaviour of flux in laminations, where the rolling directions of adjacent sheets are reversed. The paper clarifies the mechanism of the greatly different magnetic characteristics between such laminations and usual ones, where the rolling directions of adjacent sheets are coincident.</p

Enhanced thermoelectric properties by Ir doping of PtSb2 with pyrite structure

The effects of Ir doping on the thermoelectric properties of Pt1-xIrxSb2 (x = 0, 0.01, 0.03, and 0.1) with pyrite structure were studied. Measurements of electrical resistivity rho, Seebeck coefficient S, and thermal conductivity kappa were conducted. The results showed an abrupt change from semiconducting behavior without Ir (x = 0) to metallic behavior at x = 0.01. The sample with x = 0.01 exhibited large S and low rho, resulting in a maximum power factor (S^2/rho) of 43 muW/cmK^2 at 400 K. The peculiar "pudding mold"-type electronic band dispersion could explain the enhanced thermoelectric properties in the metallic state.Comment: 3 pages, 2 figure

DESIGN LOAD EVALUATION FOR TSUNAMI SHELTERS BASED ON DAMAGE OBSERVATIONS AFTER INDIAN OCEAN TSUNAMI DISASTER DUE TO THE 2004 SUMATRA EARTHQUAKE

Tsunami shelters are of great importance to mitigate casualties by earthquake-induced killer waves, and the design guidelines for their practical design are recently developed by a task committee under the Japanese Cabinet Office, since great earthquakes significantly affecting coastal regions are expected to occur in the near future in Japan. Although they propose a practical design formula to calculate tsunami loads acting on shelters, it is derived primarily based on laboratory tests with scaled models but not on damage observations. It is therefore essential to examine the design loads through comparison between observed damage and structural strength. In December 2004, a huge scale Sumatra Earthquake caused extensive and catastrophic damage to 12 countries in the Indian Ocean. The author visited Sri Lanka and Thailand to survey structural damage due to tsunami, and investigated the relationship between damage to structures, lateral strengths computed based on their member properties, and observed tsunami heights. In the survey, 28 simple structures generally found in the affected coastal regions were investigated. The investigated results show that the design tsunami loads proposed in the guidelines are found rational to avoid serious damage but may not be conservative if the load amplification due to drifting debris is taken into account

Comments on differential cross section of phi-meson photoproduction at threshold

We show that the differential cross section d_sigma/d_t of gamma p --> \phi p reaction at the threshold is finite and its value is crucial to the mechanism of the phi meson photoproduction and for the models of phi-N interaction.Comment: 8 pages, 2 figure

An improved method for determining the DC magnetization curve using a ring specimen

When the DC magnetization curve (B-H) of nonoriented material is measured in a ring specimen, there is an intrinsic error due to the assumption that the mean magnetic path length is equal to the mean geometric path length. A novel method for determining the B-H curve accurately is proposed. The validity of the method is verified by experiments</p

Electronic properties of alkali-metal loaded zeolites -- a "supercrystal" Mott insulator

First-principles band calculations are performed for the first time for an open-structured zeolite (LTA) with guest atoms (potassium) introduced in their cages. A surprisingly simple band structure emerges, which indicates that this system may be regarded as a "supercrystal", where each cluster of guest atoms with diameter $\sim$10\AA acts as a "superatom" with well-defined $s$- and $p$-like orbitals, which in turn form the bands around the Fermi energy. The calculated Coulomb and exchange energies for these states turn out to be in the strongly-correlated regime. With the dynamical mean-field theory we show the system should be on the Mott-insulator side, and, on a magnetic phase diagram for degenerate-orbital systems, around the ferromagnetic regime, in accord with experimental results. We envisage this class of systems can provide a new avenue for materials design.Comment: 4 pages, 4 figure