We propose a high-speed optical disk system using thin flexible optical disks (HS-FOD) recording up to 15,000 rpm. The thin optical disk system is composed of three technical elements: media employing a thin and flexible substrate 0.1 mm thick, a mechanical stabilizer, and a high-speed tracking servo employing a feed-forward control with zero phase error tracking (ZPET-FF control). The HS-FOD system has an optical head with numerical aperture (NA) of 0.85 and is compatible with the optical system of a Blu-ray disc or a broadcast-use optical disk. We have successfully performed disk rotation stably and have performed precisely a focus servo and a tracking servo at 15,000 rpm. We also achieved writing and reading data at 15,000 rpm and recording 252 Mbps of random pattern data and could get small values of jitter below the tolerance. These results are enough to record professional high-definition television (HDTV) video signals in formats such as HD-D5 for broadcast-use.

Please note that terms and conditions apply.Evidence of d-wave pairing in MTG-YBa 2 Cu 2.99 Li 0.01 O x crystals determined from the lowtemperature specific heat AbstractThe specific heat of a melted-textured-growth (MTG) YBa 2 Cu 2.99 Li 0.01 O x crystal has been measured from 1.8 to 30 K in different fields up to 9 T parallel to the c-axis by the thermal relaxation technique. The defects induced by Li-doping and the paramagnetic centres have a strong effect on the low-temperature specific heat. The electronic specific heat C e (T , H)/T at lower temperatures (T < 5 K) follows αT at 0 T and AH 1/2 in the magnetic field, and can be scaled on a line, C e (T , H)/T H 1/2 = F(T /H 1/2 ). These results are consistent with that of the d-wave superconductor predicted theoretically by Volovik, indicating that a Li-doped MTG-YBa 2 Cu 2.99 Li 0.01 O x crystal should be a d-wave superconductor.

We apply canonical Poisson-Lie T-duality transformations to bosonic open string worldsheet boundary conditions, showing that the form of these conditions is invariant at the classical level, and therefore they are compatible with Poisson-Lie T-duality. In particular the conditions for conformal invariance are automatically preserved, rendering also the dual model conformal. The boundary conditions are defined in terms of a gluing matrix which encodes the properties of D-branes, and we derive the duality map for this matrix. We demonstrate explicitly the implications of this map for D-branes in two non-Abelian Drinfel'd doubles.

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We have been studying a new optical disk system constructed from a flexible disk and stabilizer. The feature of the system is the extremely small axial runout that is reduced by the aerodynamic effect of the stabilizer. We experimentally demonstrated that the system had the capability of achieving an axial runout of less than 5 µm across a radial region from 35 to 55 mm at a linear velocity of 13 m/s.