Write compensation using the thermal transfer function in an optical disk.
The theoretical basis for a write-compensation scheme is developed with a simplified thermal transfer function in an optical disk. The thermal transfer function is analytically approximated to a first-order exponential filter similar to that of an integrating circuit. A write-compensation method is then given directly by the inverse function of the filter. A simplified form of the compensation is also derived, and this is verified by experiments. This method eliminates the thermal interference and shows how to form mark edges uniformly for an arbitrary optical disk.
Simplified Transfer Function of Write Compensation for Phase-Change Optical Disks
A simplified transfer function for write compensation is given by the inverse function of the cooling transfer function of a phase-change optical disk. The areas at a phase-change recording layer irradiated with an optical beam melt and change to marks. The marks are formed when the area is rapidly cooled; however, the marks disappear in a slowly cooled situation. Thus, the cooling process was considered essential for the mark formation on a phase-change optical disk. Therefore, the transfer function of the mark formation combined a heating component before mark formation with that after mark formation using a lag element. It was also found that the transfer function for write compensation could be achieved using a two-stage pulse train method. Experimental results showed that long marks were recorded by the pulse train method with the same frequency characteristic as our theoretical analysis.
Resonant Auger decay study of C1s -> pi* core-excited OCS
The present work aims at characterizing short-lived C1s((-1)) pi*((1)) core-excited states of the OCS molecule based on the analysis of the vibrational fine structure and lineshape profiles of the high-resolution resonant Auger decay spectra recorded at the excitation energies along the C1s -> pi* resonance in the binding energy region 15-19eV. Very different behavior in terms of lineshape and resonant enhancement is observed for the (A) over tilde, (B) over tilde and (C) over tilde final states. This is explained by (1) the variation in the C-O bond lengths for the states involved in the electronic relaxation and (2) different contributions in terms of Mulliken population to the molecular orbitals determining the electronic character of the corresponding states. Since the final-state geometries are known from a number of previous experiments and ab initio calculations, the geometry of the C1s((-1)) pi*((1)) intermediate states can be predicted in analogy with e.g. the N-2, CO2 and N2O molecules. (C) 2009 Elsevier B.V. All rights reserved. (Less)