Konan University

About: Konan University is a education organization based out in Kobe, Japan. It is known for research contribution in the topics: Supernova & Cosmic ray. The organization has 1714 authors who have published 3667 publications receiving 70360 citations.

Optical Properties of Single-Wall Carbon Nanotubes

Abstract: Four kinds of single-wall carbon nanotubes (SWNTs) with different diameter distribution have been synthesized and optical absorption spectra have been measured. Three large absorption bands due to the optical transitions between spike-like density of states, characteristics of SWNTs, were observed from infrared to visible region. Comparing with the calculated energy band, it has been concluded that the first and the second lowest absorption bands are due to the optical transitions between spikes in semiconductor phases and the third one is due to that in metallic phases. Absorption Peaks sensitively shifted to higher energy side with decreasing tube diameters as the band calculation predicted. Resonance Raman spectra were also measured using various laser lines. When the excitation is in an energy region corresponding to the absorption band of metallic phase, spectra have shown Breit-Wigner-Fano line shape, which is a sign of metallic phase. Using these results, we can easily characterize SWNTs from the optical absorption spectra without Raman measurements and transmission electron microscope observations.

Design concepts for the Cherenkov Telescope Array CTA: An advanced facility for ground-based high-energy gamma-ray astronomy

Abstract: Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.

Nucleosynthesis in Stars and the Chemical Enrichment of Galaxies

Abstract: After the Big Bang, production of heavy elements in the early Universe takes place starting from the formation of the first stars, their evolution, and explosion. The first supernova explosions have strong dynamical, thermal, and chemical feedback on the formation of subsequent stars and evolution of galaxies. However, the nature of the Universe's first stars and supernova explosions has not been well clarified. The signature of the nucleosynthesis yields of the first stars can be seen in the elemental abundance patterns observed in extremely metal-poor stars. Interestingly, those patterns show some peculiarities relative to the solar abundance pattern, which should provide important clues to understanding the nature of early generations of stars. We thus review the recent results of the nucleosynthesis yields of mainly massive stars for a wide range of stellar masses, metallicities, and explosion energies. We also provide yields tables and examine how those yields are affected by some hydrodynamical effe...

Introducing the CTA concept

Abstract: The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project.

Evidence for a narrow S = +1 baryon resonance in photoproduction from the neutron.

Abstract: The $\ensuremath{\gamma}n\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}n$ reaction on $^{12}\mathrm{C}$ has been studied by measuring both ${K}^{+}$ and ${K}^{\ensuremath{-}}$ at forward angles. A sharp baryon resonance peak was observed at $1.54\ifmmode\pm\else\textpm\fi{}0.01\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}/{c}^{2}$ with a width smaller than $25\text{ }\text{ }\mathrm{M}\mathrm{e}\mathrm{V}/{c}^{2}$ and a Gaussian significance of $4.6\ensuremath{\sigma}$. The strangeness quantum number ($S$) of the baryon resonance is $+1$. It can be interpreted as a molecular meson-baryon resonance or alternatively as an exotic five-quark state ($uudd\overline{s}$) that decays into a ${K}^{+}$ and a neutron. The resonance is consistent with the lowest member of an antidecuplet of baryons predicted by the chiral soliton model.