Biomedical subjects

Masaki Taya

Publications and source records attributed to Masaki Taya.

2 recordsLinked to original sources

PubMed2004

Practical method to determine the filter shape function used in the three-dimensional Fourier filtering method.

The procedure to determine the appropriate filter shape function used in the three-dimensional Fourier filtering method (3D-FFM) is discussed from a practical point of view, so as to reduce the artificial contrast induced by the processing and to achieve a high signal-to-noise ratio. The effects of cutting off the high spatial frequency of the filter shape function and damping at low spatial frequency were investigated by using through-focus images of a gold (110) thin film. In addition, the effect of the width of the filtered area was discussed using through-focus images of a carbon nanotube. For reliable image processing, the filter shape function should be cut off beyond the information limit and attenuated with damping at low spatial frequency. Furthermore, the extraction area should include the distributed area of the relevant structural components appearing in the 3-D Fourier spectrum.

Algorithms↗

PubMed2003

Quantitative analysis of surface atom positions in a thick crystal as determined by a reconstructed exit wave.

Atomic structures of an Au (110) 2 x 1 reconstructed surface were analysed quantitatively using an exit wave reconstructed by the three-dimensional Fourier filtering method in high-resolution transmission electron microscopy. To reconstruct the exit wave in a relatively thick crystal, a practical criterion was proposed in the present analysis. In the 'pseudo-exit wave' obtained by the proposed criterion, relaxation of surface atoms was clearly visible in the top three layers. The atoms' displacement was measured to be about 5-20 pm. For quantitative analysis of the atom column positions, image contrast calculations were performed using a structural model of the Au (110) reconstructed surface. Calculations confirmed that the reconstructed pseudo-exit wave could represent the atom column positions directly with an accuracy of several pm, even for a relaxed surface, provided the sample thickness was <7 nm.

Journal Article↗