15 research outputs found
Evidence for semiconducting behavior with a narrow band gap of Bernal graphite
We have studied the resistivity of a large number of highly oriented graphite
samples with areas ranging from several mm to a few m and
thickness from nm to several tens of micrometers. The measured
resistance can be explained by the parallel contribution of semiconducting
graphene layers with low carrier density cm and the one from
metallic-like internal interfaces. The results indicate that ideal graphite
with Bernal stacking structure is a narrow-gap semiconductor with an energy gap
meV.Comment: 14 pages, 4 Figures, to be published in New Journal of Physics (in
press, 2012
Evidence of Josephson-coupled superconducting regions at the interfaces of Highly Oriented Pyrolytic Graphite
Transport properties of a few hundreds of nanometers thick (in the graphene
plane direction) lamellae of highly oriented pyrolytic graphite (HOPG) have
been investigated. Current-Voltage characteristics as well as the temperature
dependence of the voltage at different fixed input currents provide evidence
for Josephson-coupled superconducting regions embedded in the internal
two-dimensional interfaces, reaching zero resistance at low enough
temperatures. The overall behavior indicates the existence of superconducting
regions with critical temperatures above 100 K at the internal interfaces of
oriented pyrolytic graphite.Comment: 6 Figures, 5 page
Construction of KAGRA: An underground gravitational-wave observatory
The major construction and initial-phase operation of a second-generation gravitational-wave detector, KAGRA, has been completed. The entire 3 km detector is installed underground in a mine in order to be isolated from background seismic vibrations on the surface. This allows us to achieve a good sensitivity at low frequencies and high stability of the detector. Bare-bones equipment for the interferometer operation has been installed and the first test run was accomplished in March and April of 2016 with a rather simple configuration. The initial configuration of KAGRA is called iKAGRA. In this paper, we summarize the construction of KAGRA, including a study of the advantages and challenges of building an underground detector, and the operation of the iKAGRA interferometer together with the geophysics interferometer that has been constructed in the same tunnel. © The Author(s) 2018. Published by Oxford University Press on behalf of the Physical Society of Japan
Oncological Applications of Positron Emission Tomography with Fluorine-18 Fluorodeoxyglucose
Positron emission tomography (PET) is now primarily used in oncological indication owing to the successful application of fluorine-18 fluorodeoxyglucose (FDG) in an increasing number of clinical indications at different stages of diagnosis, and for staging and follow-up. This review first considers the biological characteristics of FDG and then discusses methodological considerations regarding its use. Clinical indications are considered, and the results achieved in respect of various organs and tumour types are reviewed in depth. The review concludes with a brief consideration of the ways in which clinical PET might be improved