Study of a nonhomogeneous aerogel radiator in a proximity focusing RICH detector

The use of a nonhomogeneous aerogel radiator, i.e. one consisting of layers with different refractive indices, has been shown to improve the resolution of the Cherenkov angle measured with a proximity focusing RICH detector. In order to obtain further information on the performance of such a detector, a simple model has been used to calculate the resolution and search for optimal radiator parameters.Comment: Submitted to Nucl. Instr. Met

Study of Rare B Meson Decays at Belle

In this paper, we briefly review results on rare decays of $B$ mesons from the Belle experiment, based on 10.4 fb$^{-1}$ data collected on the $\Upsilon$(4S) resonance. The topics include measurements of Cabibbo suppressed decays $B \to D^{(*)} K^{(*)}$, charmless two-body decays $B \to \pi\pi$, $K\pi$, $KK$ and $B \to \eta^{'} h (h = K^+, \pi^+, K^0)$, and a search for flavor changing neutral current decays $B \to K^{(*)} \ell^{+} \ell^{-}$.Comment: 21 pages, 8 figures, Contribution to the Proceedings of the 4th International Workshop on B Physics and CP Violation (BCP4), February 19-23, 2001, Ise-Shima, Japa

Development of single nanometer-sized ultra fine oxygen bubbles to overcome the hypoxia-induced resistance to radiation therapy via the suppression of hypoxia-inducible factor-1α

学位記番号：医博甲1681

Minimal and maximal constituents of twisted Foulkes characters

We prove combinatorial rules that give the minimal and maximal partitions labelling the irreducible constituents of a family of characters for the symmetric group that generalize Foulkes permutation characters. Restated in the language of symmetric functions, our results determine all minimal and maximal partitions that label Schur functions appearing in the plethysms $s_\nu \circ s_{(m)}$. As a corollary we prove two conjectures of Agaoka on the lexicographically least constituents of the plethysms $s_\nu \circ s_{(m)}$ and $s_\nu \circ s_{(1^m)}$

Selective production of metallic carbon nanotubes

In this report, we discuss whether the optimal electric field to promote the growth of armchair- type nanotubes (metallic character) evaluated using the previous Huckel-Poisson method can be applied at the tip of a nanotube in a realistic system. Setting the cross-section of a nanotube and the external field by the sheath, we estimate an effective area at the sheath edge. Since the electric charge distribution in a nanotube caused by the external electric field was determined in our previous study, we obtained the electric field distribution out of a nanotube by solving the Poisson equation and clarified the structure of the electric field lines. By determining the effective area, we show the optimal interval of the catalyst metal, which is necessary to selectively grow the metallic nanotubes. When nanotubes grow thickly during the initial stage of growth, a strong electric field cannot be applied to the tips of the tubes. As a tube grows and the tube length increases, we found that the optimal electric field decreased. To maintain the chemical activity at the tip, the sheath electric field must be decreased. We estimated the decreasing rate of the sheath field to the tube length.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France