An improved technique for holographic recording on a thermoplastic photoconductor

A new method for holographic recording on a thermoplastic-photoconductor has been developed. By using this new method which involves the application of white light to the thermoplastic-photoconductor after exposure, the sensitivity, reciprocity and signal-to-noise ratio have been improved. A higher diffraction efficiency (about 30%) can also be obtained.     

Remarkable diastereomeric rearrangement of an alpha-acyloxy beta-ketosulfide to an alpha-acyloxy thioester: a novel approach to the synthesis of optically active (2S,3S) beta-amino alpha-hydroxy acids

[reaction: see text] A novel and efficient synthetic method is described for (2S,3S)-3-amino-2-hydroxy-4-phenyl butyric acid derivatives, which are useful intermediates of enzyme inhibitors. This involves a Pummerer rearrangement of a beta-ketosulfoxide derived from l-phenylalanine followed by highly stereoselective acyl migration. From these studies, it appears that nitrogen-protecting groups exert a substantial influence over stereoselectivity. The mechanism of the rearrangement is discussed. beta-Amino alpha-hydroxy carboxylic acids are important pharmaceutical intermediates, and this method may provide a versatile synthesis from various amino acids in a few steps.     

Photoluminescence of CuGaS2 and heterostructure formation with sputtered ZnS

Summary CuGaS₂ crystals grown by iodine transport exhibit room temperature photoluminescences at 2.45 eV and at 1.44 eV. The spectral distribution of the green emission is shown to be relatively well described by the calculated curve for a direct band-to-band transition withk-selection. The heterojunction formation has been tried between sulfur-treated CuGaS₂ crystals and low-resistivity amorphous ZnS films prepared by sputtering at room temperature. TheI–V characteristic of the diode shows rectifying behaviour, but no injection luminescence has been observed. Paper presented at the ?V International Conference on Ternary and Multinary Compounds?, held in Cagliari, September 14–16, 1982.     

Measurement of elastic deformation of rotating objects by using holographic interferometry

Double-exposure holographic interferometry is applied to measure the elastic deformation of rotating objects. The first exposure is made in the rotating state and the second in the static state. The precise positioning of the object between the two exposures is obtained by using holographically produced Haidinger's fringes.     

Selective determination of pentoses,hexoses and 6-deoxyhexoses by dual-wavelength spectrophotometry with the cysteine—phenol—sulfuric acid system

A convenient method is described for the selective determination of pentoses, hexoses and 6-deoxyhexoses by dual-wavelength spectrophotometry with the l-cysteine—phenol—sulfuric acid system. Excellent linearity was observed for 25–250 nmol of pentoses, and for 25–500 nmol of hexoses and 6-deoxyhexoses. These aldoses in those sample ranges could be determined selectively with high accuracy and precision by the k -factor mode. The appropriate, wavelength of λ₂ was 462, 499 and 398 nm for pentoses, hexoses and 6-deoxyhexoses, respectively, whereas that of λ₁ was commonly 424 nm.     

The motion of interfaces and the similarity dimension

A discrete model of interfaces with self-similarity is proposed to show the power-law decay of the total area. In the case that the similarity dimension is equal to the spatial dimension a $\text{t}{}^{\mathrm{<mtext>?</mtext><mtext>1</mtext><mtext>2</mtext>}}$ law appears.     

Measurement of temporal changes in vocal tract area function from 3D cine-MRI data

A 3D cine-MRI technique was developed based on a synchronized sampling method [Masaki et al., J. Acoust. Soc. Jpn. E 20, 375-379 (1999)] to measure the temporal changes in the vocal tract area function during a short utterance /aiueo/ in Japanese. A time series of head-neck volumes was obtained after 640 repetitions of the utterance produced by a male speaker, from which area functions were extracted frame-by-frame. A region-based analysis showed that the volumes of the front and back cavities tend to change reciprocally and that the areas near the larynx and posterior edge of the hard palate were almost constant throughout the utterance. The lower four formants were calculated from all the area functions and compared with those of natural speech sounds. The mean absolute percent error between calculated and measured formants among all the frames was 4.5%. The comparison of vocal tract shapes for the five vowels with those from the static MRI method suggested a problem of MRI observation of the vocal tract: data from static MRI tend to result in a deviation from natural vocal tract geometry because of the gravity effect.