A method for production of fiber-reinforced metal composite material having high fiber content, wherein a bundle of fiber material is impregnated with water, then this water-impregnated fiber bundle is subjected to compression and freezing to form a high density fiber shaped body, subsequently, the high density fiber shaped body is subjected to thawing and drying, while maintaining its shape as compressed, and finally molten metal is infiltrated into the fiber shaped body.

An adaptive digital filter is connected in parallel with a transmission system and includes a plurality of delay circuits, a nonrecursive digital filter having coefficient parameters of the delay circuits so as to approximate the characteristics of the transmission system, and a correction circuit for correcting the coefficient parameters of the nonrecursive digital filter. The adaptive digital filter further includes a first variable attenuator, a second variable attenuator and a comparator. Th...

A novel method is proposed for the preparation of a transparent fused silica glass body co-doped with a rare earth element and aluminum each in a high uniformity of the dopant distribution. The method comprises the steps of: (a) flame-hydrolyzing a silicon compound and an aluminum compound in an oxyhydrogen flame to form a porous silicon oxide body containing aluminum; (b) soaking the porous body having a specified bulk density with a solution of a rare earth compound; (c) drying the solution-so...

The optical amplification gain of an optical amplifier consisting of an optical amplifier unit and a single-mode erbium-doped fiber can be optimized when the length of the fiber L in meters and the optical absorption in dB/meter of the fiber per unit length at a wavelength of 1.53 .mu.m satisfy the relationship that L.times.y is in the range from 70 to 170 dB by appropriately selecting the doping level of the glass with erbium and the length of the fiber.

Disclosed is a light-sensitive lithographic printing plate which comprises an aluminum plate having a surface subjected to roughening treatment and then anodization treatment and colored by a solution containing a UV absorber so that at an absorption local maximum wavelength between 340 and 450 nm, reflection optical density DS is higher by 0.02 to 0.5 than that obtained when the surface is not colored, and a positive light-sensitive composition layer containing an o-quinonediazide compound and ...