Dielectric anomaly in coupled rotor systems

The correlated dynamics of coupled quantum rotors carrying electric dipole moment is theoretically investigated. The energy spectra of coupled rotors as a function of dipolar interaction energy is analytically solved. The calculated dielectric susceptibilities of the system show the peculiar temperature dependence different from that of isolated rotors.Comment: 5 pages, 4 figures (Figure 2 is available on request from [email protected]

Glass-like Thermal-Transport in Symmetry-Broken Clathrates

We present the quantitative interpretation for the glass-like behavior of thermal conductivities $\kappa(T)$ for type-I clathrate compounds involving off-centered guest ions. It is shown that the dipole-dipole interaction generated in cage/guest-ion systems is crucial to reproduce the characteristics of thermal conductivities for these symmetry-broken clathrates. The above scenario also explains well the difference of $\kappa(T)$ between the $p$-type and the $n$-type $\beta$-BGS found recently by K. Suekuni et al. [Phys. Rev. B, 77 (2008) 235119.

Retinal adaptation of Japanese common squid (Todarodes pacificus Steenstrup) to light changes

The response of retinae of the Japanese common squid (Todarodes pacificus Steenstrup) was recorded in relation to various light intensities. In the light-adapted eye of common squid, the black pigment ascends to the external limiting membrance of the retina. Conversely, in the dark-adapted eye the black pigment descends toward the center of the black pigment layer. To express the degree of adaptation, the authors give the ratio of the height (thickness) of the black pigment to the total height (thickness) of the retina as a percentage (%)

Phonon-glass electron-crystal thermoelectric clathrates: Experiments and theory

Type-I clathrate compounds have attracted a great deal of interest in connection with the search for efficient thermoelectric materials. These compounds constitute networked cages consisting of nano-scale tetrakaidecahedrons (14 hedrons) and dodecahedrons (12 hedrons), in which the group 1 or 2 elements in the periodic table are encaged as the so-called rattling guest atom. It is remarkable that, though these compounds have crystalline cubic-structure, they exhibit glass-like phonon thermal conductivity over the whole temperature range depending on the states of rattling guest atoms in the tetrakaidecahedron. In addition, these compounds show unusual glass-like specific heats and THz-frequency phonon dynamics, providing a remarkable broad peak almost identical to those observed in topologically disordered amorphous materials or structural glasses, the so-called Boson peak. An efficient thermoelectric effect is realized in compounds showing these glass-like characteristics. This decade, a number of experimental works dealing with type-I clathrate compounds have been published. These are diffraction experiments, thermal and spectroscopic experiments in addition to those based on heat and electronic transport. These form the raw materials for this article based on advances this decade. The subject of this article involves interesting phenomena from the viewpoint of not only physics but also from the view point of the practical problem of elaborating efficient thermoelectric materials. This review presents a survey of a wide range of experimental investigations of type-I clathrate compounds, together with a review of theoretical interpretations of the peculiar thermal and dynamic properties observed in these materials.Comment: 51pages, 43 figure

Models of schooling in the global age: the case of Japan

In sum, in Japan today, we see a society that shares many educational trends with the rest of the world (e.g. globalization), while maintaining distinct features of its model of schooling. Some parts of this model have been introduced internationally, while other parts of it are seen as domestic