Abstract: An optical information recording medium recordable at a high density two times or more higher than that of currently-used CD-Rs by devising the shape of a pregroove is provided. It is provided with a recording layer formed on a transparent substrate having a spiral pregroove formed thereon, wherein a track pitch Tp of the pregroove is 1.0 &mgr;m≦Tp≦1.2 &mgr;m and an inclination angle Ga of sidewalls of the pregroove is 30°≦Ga≦70°.

Abstract: An optical information recording medium recordable at a high density two times or more higher than that of currently-used CD-Rs by using a material having optimum optical characteristics as an organic dye material of a recording layer. The optical information recording medium comprises a recording layer on a transparent substrate having a spiral pregroove formed thereon, wherein the track pitch Tp of the pregroove is 1.0 &mgr;m≦Tp≦1.2 &mgr;m and the optical phase difference &Dgr;S is 0.15≦&Dgr;S≦0.55.

Abstract: An optical information recording medium recordable at a high density two times or more higher than that of currently-used CD-Rs by optimally determining the thicknesses of a recording layer and a reflecting layer. The optical information recording medium comprises the recording layer formed on a transparent substrate having a spiral pregroove formed thereon, wherein a track pitch Tp of the pregroove is 1.0 &mgr;m≦Tp≦1.2 &mgr;m and a thickness Dg of the recording layer on the pregroove is 80 nm≦Dg≦120 nm.

Abstract: A body fluid sample is diluted with a diluent which comprises an aqueous solution containing bis(2-hydroxyethyl)-iminotris(hydroxymethyl)methane and boric acid to obtain a diluted body fluid sample, and the ion concentration in the diluted body fluid sample is determined with ion-selective electrodes, whereby the variation width of pH in the diluted body fluid sample can be held down to a narrow range. As a result the determination can be made without exerting adverse effects on the ion-selective electrodes, and errors in determination can be markedly reduced as compared with cases where the conventional diluents are used.

Abstract: A microwave filter includes a plurality of resonator cavities which are separated by walls and which have respective resonator rods, and trimming caps made of a dielectric substance are fixed to the respective resonator rods.

Abstract: In a microwave filter including a plurality of resonator cavities, at least one of the windows between cavities for coupling them is formed near the end portions of the resonance rods in the cavities, and a part of one of the coupling loops for transmitting signals of microwave frequencies is coplanar with the opening thereby to form an attentuation pole capable of abrupt attenuation of any image frequency.

Abstract: A filter for microwaves includes a plurality of resonator cavities each having a housing formed unitarily with a respective resonance rod. The neighbouring resonator cavities are coupled together by means of a coupling window formed in the wall separating the cavities and a coupling loop, and a hole communicating with the coupling window is formed in the bottom plate of the filter.