33,492 research outputs found
Ultra-high resolution Fourier domain optical coherence tomography for resolving thin layers in painted works of art
While OCT has been applied to the non-invasive examination of the stratigraphy of paint layers in recent years, it has been recognized that the resolutions of commercially available OCT cannot compete in depth resolution with conventional microscopic examination of cross-sections of paint samples. It is necessary to achieve resolutions better than 3 microns to resolve the thinnest layers of paint and varnish. In this paper, we demonstrate a Fourier domain ultrahigh resolution OCT at 810nm with depth resolution of 1.8μm in air (or 1.2μm in varnish or paint)
Properties of nano-graphite ribbons with zigzag edges -- Difference between odd and even legs --
Persistent currents and transport properties are investigated for the
nano-graphite ribbons with zigzag shaped edges with paying attention to system
length dependence. It is found that both the persistent current in the
isolated ring and the conductance of the system connected to the perfect leads
show the remarkable dependences. In addition, the dependences for the
systems with odd legs and those with even legs are different from each other.
On the persistent current, the amplitude for the cases with odd legs shows
power-low behavior as with being the number of legs, whereas the
maximum of it decreases exponentially for the cases with even legs. The
conductance per one spin normalized by behaves as follows. In the even
legs cases, it decays as , whereas it reaches to unity for in the odd legs cases. Thus, the material is shown to have a remarkable
property that there is the qualitative difference between the systems with odd
legs and those with even legs even in the absence of the electron-electron
interaction.Comment: 4 pagaes, 8 figures, LT25 conference proceeding, accepted for
publication in Journal of Physics: Conference Serie
Reversibility Checking for Markov Chains
In this paper, we present reversibility preserving operations on Markov chain
transition matrices. Simple row and column operations allow us to create new
reversible transition matrices and yield an easy method for checking a Markov
chain for reversibility
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