Shiseido Company, Limited

Masahiro Matsuoka

Tsuguo Sawada

Masashi Kikuchi

Ryuichi Takamoto

Ryujiro Nanba

A photoacoustic cell, including a light guide having a fiber portion consisting of a bundle of a number of optical fibers and a covering portion by which the side surface of the fiber portion is covered, the covering portion of the light guide extending beyond the fiber portion in a manner that when a first end of the light guide is brought into contact with the surface of a material to be measured, a closed space is defined by the end surface of the fiber portion, by the inner wall of the covering portion, and by the surface of the material to be measured; a pipe having a first end that is open in the closed space and a second end that penetrates through the covering portion and is open toward the outside of the covering portion; and a microphone that is coupled to the second end of the pipe, and a photoacoustic measuring device including this photoacoustic cell.

Photoacoustic cell and photoacoustic measuring device

A naphthalene derivative having the general formula: ##STR1## wherein R represents hydrogen, an alkyl group having 1 to 8 carbon atoms, an R.sup.1 O (CH.sub.2).sub.n group, or a benzyl group, R.sup.1 represents hydrogen or a lower alkyl group, and n represents an integer of 2 or 3. This compound in the leuco state can be stably isolated and can produce a strong and fast color upon oxidation under moderate conditions. This compound can be advantageously included in a hair dye composition, which is capable of stably and safely dyeing hair with a good and stable color under moderate conditions.

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Yokohama, Japan

Masahiro Matsuoka