Abstract: An ultrasonic transducer unit for use in pulse-echo ultrasonic investigation has a plurality of components including a piezoelectric ultrasonic wave transmitting element, an acoustoelectric ultrasonic wave receiving element and electrodes therefor. To provide a compact and efficient transducer, these components are bonded together in an integrated multilayer structure in which the transmitting element and receiving element are superimposed in the direction of propagation of transmitted and received ultrasonic waves. The receiving element may be a ZnO single crystal. An insulating layer isolates two components from each other.

Abstract: A phase-insensitive ultrasonic transducer has a zinc oxide single crystal as a piezoelectric semiconducting acoustoelectric element, providing high sensitivity and operable over a range of wavelengths of the ultrasonic waves. The electrical conductivity of said zinc oxide single crystal may be selected in the range 10.sup.-8 to 10.sup.-2 .OMEGA..sup.-1.cm.sup.-1. The single crystal can have an attenuation rate for ultrasonic waves of 10 MHz of at least 0.8 cm.sup.-1.

Abstract: A solid oxide fuel cell is disclosed, which includes flat plate-shaped solid oxide fuel cell elements. The solid oxide fuel cell element includes an ion-conductive ceramic plate, and an air electrode and a fuel electrode formed on opposite surfaces of the ion-conductive ceramic plate, respectively, wherein conductive strips which have less resistance than the electrode are continuously formed on a surface of at least one of the air electrode and the fuel electrode.

Abstract: A solid oxide fuel cell including a flat plate-shaped solid oxide fuel cell element. The cell element is composed of an ion-conductive ceramic plate formed with ribs connected with each other in a plane, an air electrode formed on one main surface of the ion-conductive ceramic plate, and a fuel electrode formed on the other main surface of the ion-conductive ceramic plate. In producing the fuel cell, a flat plate-shaped green sheet made of an ion-conductive ceramic molding material is press contacted with a rib-forming green sheet made of a material of the same kind and having a unitary shape formed by connecting elongated portions to each other. The contacted green sheets are sintered together to form an ion-conductive ceramic plate. In an alternative, a flat plate-shaped green sheet and a rib-forming green sheet may be separately sintered and then bonded with each other to form an ion-conductive ceramic plate.

Abstract: There is disclosed a process for continuously and efficiently producing a styrenic polymer having a high degree of syndiotactic configuration which comprises effecting polymerization reaction by continuously introducing a styrenic monomer and a polymerization catalyst into a polymerization reactor, the inside of which has been brought into fluidized state by particles previously fed therein, which process is characterized in that the polymerization reactor temperature is controlled by vaporizing a part of the styrenic monomer which has been introduced into the polymerization reactor, while the inside of the reactor is maintained under reduced pressure. According to the above process, such problems as difficulty in polymerization reactor scale-up, adhesion of polymer to the reactor inside and polymer particle agglomerate are simultaneously solved, and thereby the industrial significance of the process is remarkably enhanced.

Abstract: A solid oxide fuel cell comprising a separator plate made of a material having stability against oxidation and reduction and electronic conductivity, an air electrode spacer made of a material having oxidation resistance and electronic conductivity, a flat plate-shaped solid oxide fuel cell element, a fuel electrode spacer, and another separator plate made of a material having oxidation resistance, reduction resistance and electronic conductivity, and another separator plate. The separator plate, the air electrode spacer, the solid oxide fuel cell element, the fuel electrode spacer and another separator plate are successively laminated in this order. The solid oxide fuel cell element including an ion-conductive ceramic plate, and an air electrode and a fuel electrode formed on opposite surfaces of said ceramic plate, respectively.

Abstract: A method for continuous thermogravimetric analysis of coal, or other materials rich in carbon, for volatile matter and ash content, including the steps of exposing a coal sample to an atmosphere consisting essentially of about 1 to 5% by volume of oxygen and the remainder being nitrogen and inevitable impurities at a first specified temperature for a first given time, weighing the coal sample to determine a first weight loss during the first given time, the first weight loss corresponding to the amount of volatile matter in the coal sample, burning the coal sample under an oxygen atmosphere having a higher than normal oxygen concentration for a second given time at a temperature sufficient to burn carbon containing materials in the coal sample, and weighing the coal sample to determine a second weight loss during the first given time and the second given time, the second weight loss corresponding to the amount of volatile matter and the amount of ash content in the coal sample.

Abstract: In a metal-ceramic combination wherein a monobloc ceramic member comprising a base, a protrusion integrally formed on the base and an easement portion on and around the root of the protrusion, is combined with a metallic member, an improved combination having an excellent strength in total is obtained by fitting the protrusion tightly into a recession or conduit of the metallic member, leaving clearance of 0.5 mm or more between the easement portion and a defined edge of joint interface of the said two members. The combination of the invention is particularly useful for engine parts to be subjected to high temperatures and repeated stresses such as a turbocharger rotor, piston, tappet, rocker arm, exhaust valve, cam and the like.

Abstract: A ceramic valve seat is disclosed herein. A face portion of the valve seat at which the valve seat is to contact with a valve is made of a ceramic material. At least edge portions of the valve-contacting face portion of the valve seat are rounded. By so constructing, impact force due to contact between the valve and the valve seat and stress concentration can be mitigated.

Abstract: Disclosed herein is a metal-ceramic composite body having a ceramic member with a small diameter portion and a large diameter portion which are formed by providing a ceramic member with a projection and a metallic member with a recessed portion or through hole. The ceramic member and the metallic member are bonded together by inserting the small diameter portion into the recessed portion or through hole such that a space being not less than the diameter of the small diameter portion is provided between the edge surface of the metallic member on the side of the ceramic member at the bonding portion and the back surface of the large diameter portion of the ceramic member. The thickness of the edge portion of the metallic member is gradually reduced toward the ceramic member at a radius of curvature of not smaller than 0.4 times as large as the diameter of the small diameter portion. A method of producing the metal-ceramic composite body is also disclosed herein.