Abstract: Examples of a cleaning method includes supplying a cleaning gas into an exhaust duct that provides an exhaust flow passage of a gas supplied to an area above a susceptor, the exhaust duct having a shape surrounding the susceptor in plan view, and activating the cleaning gas to clean an inside of the exhaust duct.

Abstract: An optical recording medium includes at least a substrate and a recording layer formed on the substrate, said recording layer being irradiated with an energy beam to change the optical properties thereof by directly or indirectly generated heat, thereby recording information, wherein said recording layer comprises four elements of tellurium (Te), germanium (Ge), gallium (Ga) and bismuth (Bi) and has a composition represented by the following formula:(Te.sub.x Ge.sub.1-x).sub.1-y (Ga.sub.z Bi.sub.1-z).sub.ywherein0.40.ltoreq.x.ltoreq.0.750.02.ltoreq.y.ltoreq.0.30 and0.05.ltoreq.z.ltoreq.0.50,x is the molar fraction of Te in Te-Ge, y is the molar fraction of the total amount of Bi and Ga in the recording layer, and z is the molar fraction of Ga in Ga-Bi.

Abstract: In an optical recording medium of the type on which information can be written, erased, and read by irradiating light to a recording layer formed on a substrate and in which writing and erasing of the information are effected by phase transition between an amorphous phase and a crystalline phase, this invention relates to an optical recording medium which includes at least a recording layer and protective layers and the composition of the recording layer comprises at least one kind of metals selected from the group consisting of palladium (Pd), nickel (Ni), silver (Ag), and gold (Au); antimony (Sb); germanium (Ge); and tellurium (Te), and is expressed by the formula given below. The present invention provides an optical recording medium which has a high erasing speed, is excellent in recording characteristics such as a carrier-to-noise ratio, an erase ratio, recording sensitivity, etc.

Abstract: A piezoelectric polymeric material having utility in ultrasonic transducers is disclosed which consists essentially of a copolymer of about 65 to 82 mol percent of vinylidene fluoride and about 35 to 18 mol percent of ethylene trifluoride. The polymeric material is formed into a film of the desired thickness and then heated to a temperature greater than about the crystal phase transition temperature and less than about the melting-point temperature to produce a heat-treated film. The heat-treated film is poled in an electrical field of from about 50 to about 1,500 kilovolts per centimeter to give the film a thickness extensional electromechanical coupling factor of at least 0.05 and preferably greater than 0.2.

Abstract: An ultrasonic transducer is disclosed which includes a vibrating element comprising a sheet of a piezoelectric polymeric material which consists essentially of a copolymer of about 65 to 82 mol percent of vinylidene fluoride and about 35 to 18 mol percent of ethylene trifluoride. The polymeric material is formed into a film of the desired thickness and then heated to a temperature greater than about the crystal phase transition temperature and less than about the melting-point temperature for a period of time of about ten minutes to about two hours to produce a heat-treated film. The heat-treated film is poled in an electrical field of from about 50 to about 1,500 kilovolts per centimeter to give the film a thickness extensional electromechanical coupling factor of at least 0.05 and preferably greater than 0.2.

Abstract: A piezoelectric vibration transducer is disclosed which includes a polymeric piezoelectric film as the active element. The film is a selectively or fully polarized, uniaxially oriented material selected from the group of polyvinylidene fluoride, blended material such as polyvinylidene fluoride and PZT powder, polyvinyl fluoride, polyacrylonitrile, copolymers or vinylidene fluoride such as vinylidene fluoride and tetrafluoroethylene or trifluoroethylene. The film is bonded to electrode strips formed by printed circuit methods and then overcoated with a front electrode layer. The sandwich formed by the electrode layers and intermediate polymeric piezoelectric film can be reversed so that the front electrode layer is discontinuous while the back electrode layer is continuous, or both electrode layers can be formed to be discontinuous. Special configurations for the discontinuous pattern of electrode layers can be employed such as that specified by Fresnel's theory.

Abstract: An ultrasonic transducer element includes a polymer piezoelectric film having a plurality of sections. The sections are defined by wave planes of ultrasonic waves having substantially .lambda./2 phase difference emanated from an imaginary focal point or line located in front of the piezoelectric film. .lambda. is the wave length of the ultrasonic waves within an acoustic transmission medium located between the piezoelectric film and the imaginary focal point or line. The sections are arranged so that ultrasonic waves emanated from adjacent sections have substantially no phase difference at the imaginary focal point or line. Front and rear electrodes are deposited on opposite surfaces of the piezoelectric film.

Abstract: Ultrasonic transducer advantageously usable for diagnostic purpose includes a piezoelectric element such as a PVDF film backed with a reflective layer of a reduced thickness specified in relation to the wavelength of sound waves within the reflective layer at one-half of the free resonant frequency of the piezoelectric element. Remarkable reduction in thickness assures high transfer efficiency, broad available frequency-band and easy application of fine treatments such as etching.

Abstract: A method for the manufacture of man-made fish-gathering plates having specific gravity between about 1.2 to 1.8 comprising the steps of providing a charge of raw material consisting of subdivided composite plastic consisting of at least two types of thermofusible plastic material or at least one type of thermofusible plastic material and non-plastic material, forming a molten mass from said charge of raw material by mixing by an agitator said charge with particulate inorganic material so the molten mass contains 25 to 70 weight percent of thermofusible plastic material as a bonding agent, said inorganic material being preheated to a temperature suitable for melting the thermofusible plastic material as a bonding agent and said agitator being kept at substantially the same temperature, charging the molten mass into a mold in a press machine to form it into a shape conforming to the shape of the mold, and after cooling solidifying the resulting shaped article, removing it from the mold.