Abstract: A substrate 18, a cathode 20 and an anode 22 are stored in a space demarcated by a casing 10, and the space is evacuated. The cathode 20 and the anode 22 are provided on the same surface of a substrate 18 having electric insulation, and have a comb-tooth shape so as to be mutually engaged. Therefore, the area of the part in which the cathode 20 and the anode 22 approach each other becomes larger, and thereby photoelectrons discharged from the cathode 20 through the incidence of ultraviolet rays are transmitted in the vacuum, and are favorably collected in the anode 22.

Abstract: A substrate 18, a cathode 20 and an anode 22 are stored in a space demarcated by a casing 10, and the space is evacuated. The cathode 20 and the anode 22 are provided on the same surface of a substrate 18 having electric insulation, and have a comb-tooth shape so as to be mutually engaged. Therefore, the area of the part in which the cathode 20 and the anode 22 approach each other becomes larger, and thereby photoelectrons discharged from the cathode 20 through the incidence of ultraviolet rays are transmitted in the vacuum, and are favorably collected in the anode 22.

Abstract: The present invention relates to a ceramic fiber yarn, which has higher weaving and knitting performance. The ceramic fiber yarn comprises a group of filaments, the filaments being made by the steps of spinning mother liquid, which comprises colloidal silica and basic aluminum chloride, and firing, the filaments comprising 67-75 wt % of alumina and 25-33 wt % of silica and mainly having polycrystalline transition alumina, and is characterized in that: the loop strength of each the filament, which is measured by a wire having diameter of 0.5 mm, is at or greater than 2.5.times.10.sup.-2 N (N: Newton); and the crystal structure of the filament substantially changes to polycrystalline mullite after heating for 30 minutes at the temperature of 1,400.degree. C.

Abstract: An ultrasonically modulated laser comprises a laser oscillation tube including opposing ends for generating a beam of planar polarized light having a plurality of wavelenghts; an output mirror at one end of the tube for reflecting the light beam; and a modulation device at the other end of the tube for simultaneously modulating a plurality of wavelengths of the light beams, including an acousto-optical prism having an incident surface for separating the beam into multiple wavelength components, a total reflection mirror for receiving and reflecting selected wavelength components impinging on the incident surface from the tube at a predetermined angle, and an ultrasonic transducer for generating standing means perpendicular to the selected wavelength components for modulating the reflected selected wavelength components.