Abstract: An oxygen concentration detecting device comprises a solid electrolyte body, inner and outer electrodes formed on the opposite sides of the solid electrolyte body, and a protective layer formed on the outer electrode and comprised of coarse particles and fine particles mutually bonded through an inorganic binder while substantially keeping the original forms of the both types of particles. A ratio of an average particle size, RB, of the coarse particles to an average particle size, RA, of the fine particles of 30:1 or above, and a content, WA, of the fine particles in the protective layer based on the total content, W, of the content, WA, of the fine particles and the content, WB, of the coarse particles on the weight basis is in the range of 15 to 80 %. A method for fabricating the detecting device having such a protective layer as set out above is also described.

Abstract: A positive TCR thermistor device has excellent electrical contact between a heat generator and heat radiating blocks and high heat transfer efficiency therebetween. The positive TCR thermistor includes a heat generator having a positive temperature coefficient of resistance and heat radiating blocks supplying electric current to the heat generator and heating a heated medium by receiving heat generated by the heat generator. The heat generator is provided with a metallic paste electrode at a contact surface which is in contact with the heat radiating blocks and oil having flowability is disposed between the metallic paste electrode of the heat generator and the heat radiating blocks.

Abstract: An oxygen sensor element for detecting an oxygen concentration, the oxygen sensor includes a solid electrolyte; a porous film covering the solid electrolyte at the gas-measuring side; and a reaction electrode provided on the porous film; wherein the porous film includes ceramic particles and metallic particles, and the metallic particles are bonded with the reaction electrode by a metallic bond. In this way, the porous film includes the ceramic particles and the metallic particles to form an irregular surface, and the reaction electrode is adhered to the irregular surface of the porous film in such a manner that the electrode bites into the surface of the porous film. The metallic particles in the irregular surface of the porous film are tightly bonded to the reaction electrode by the metallic bond.

Abstract: According to the present invention, an oxygen sensor element includes a solid electrolyte having a side surface at one side thereof, the side surface being contactable with a gas to be measured, a skeletal electrode provided on the side surface and having a plurality of pore portions, each of the pore portions passing through the skeletal electrode up to the solid electrolyte, and a reactive electrode made of a porous film and provided in each of the pore portions, a thickness of the porous film being smaller than that of said skeletal electrode. An area percentage (SH/SZ) which is a ratio of a total area (SH) of the reactive electrode to a total area (SZ) of the skeletal electrode and the reactive electrode is in a range from 10 to 50%, an average area (SA) of the pore portions is 100 .mu.m.sup.2 or less, a film thickness of the skeletal electrode is in a range from 1.5 to 4 .mu.m, and the film thickness of the reactive electrode is in a range from 0.6 to 1.5 .mu.m.

Abstract: To provide an oxygen sensor having a heater unit without being broken by vibration impact of a vehicle, the oxygen sensor includes a cylindrical oxygen detecting element with a closed bottom and a heater unit installed in an inside of the oxygen detecting element. The heater unit includes insulators, the heat generating body helically wound a surface thereof and lead wires. In the insulators, concave portions reaching lead holes are disposed. Lead wires are put through the lead holes from an outer circumferential surface. In the concave portions, the heat generating body and the lead wires are connected. The outer circumference of a winding portion of the heat generating body is preferably formed at a position more inwardly than the outer circumferential surface of the adjacent insulator.

Abstract: Anti-reducing semiconducting porcelain having a positive temperature coefficient of resistance comprises a barium titanate composition, and a flux containing 0.14 to 2.88 parts by weight of TiO.sub.2 0.1 to 1.6 parts by weight of Al.sub.2 O.sub.3 and 0.1 to 1.6 parts by weight of SiO.sub.2 per 100 parts by weight of the barium titanate composition. It has a high positive temperature coefficient of resistance which does not show any appreciable change in the presence of a reducing atmosphere, such as hydrogen gas or gasified gasoline. It need not be isolated from a reducing atmosphere by a plastic or metallic enclosure, but can be exposed thereto. The flux may further contain a zinc, potassium or lithium compound.

Abstract: A positive ceramic semiconductor device having positive temperature coefficient of resistance comprises a pair of electrodes provided on a ceramic semiconductor substrate. One of the paired electrodes which is to serve as the positive pole is basically constituted by at least an electrically conductive layer of silver-palladium series containing silver and palladium at a predetermined ratio. For preventing a localized current concentration from occurring in the current conducting state, improvement is made as the structure of the positive pole electrode ormed of the electrically conductive material of silver-palladium series and/or the structure of the negative pole electrode. Silver-migration phenomenon on the positive ceramic semiconductor substrate as well as degradation of the mechanical strength thereof is positively prevented.

Abstract: A self-temperature controlling type heating device comprises a positive temperature coefficient ceramic resistor having a thin layer portion, a first electrode provided on one face of the thin layer portion, a second electrode provided on the other face of the thin layer portion opposite to the first electrode, and at least one third electrode provided on the surface of the PTC ceramic resistor in spaced relation to the first electrode. An electric current is allowed to flow between the first and second electrodes to form a heating element, and an electric resistance value between the first and third electrodes is detected to thereby make a temperature control. Thus, a high output is obtained at a low voltage and the control temperature is freely varied.

Abstract: An air heater for heating intake air for an internal combustion engine only in cold start or further warming up operation, having a frame which defines an opening for passing air therethrough, and at least one heater element in the shape of a perforated plate such as a lattice or honeycomb plate supported by the frame so as to traverse only a part of the opening area of the air passage opening, while leaving a substantial part of the opening area free as untraversed by the heater element.

Abstract: A heating device of the present invention has a heating element of a substantially V-shape and is made of a ceramic material having electric conductivity. Electrode plates are respectively mounted at both ends of the heating element for energizing the heating element. Further, the heating device has a holder for holding the heating element by interposing both ends of the heating element therebetween. This holder is composed of a pair of insulating plates made of an electric insulating material. Both ends of the heating element are formed with projections. One of the insulating plates is formed with recesses for receiving both ends of the heating element in coincidence with the shape of both ends of the heating element.

Abstract: An exhaust gas purifying filter having a multiplicity of inward being open at the one axial end and blocked at the other axial end, a multiplicity of outward passages parallel to the axis of the filter, the outward passages being open at one axial end and blocked at the other axial end, and having porous partition walls placed between the inward passages and the outward passages and separating the inward passages and the outward passages from one another, which is characterized in that the surface of the partition wall exposed to at least the inward passage has superficial pores communicating with internal pores in the partition wall, the superficial pores being composed of small pores having a diameter of 5 to 40 .mu.m and large pores having a diameter of 40 to 100 .mu.m, the number of the small pores being 5 to 40 times that of said large pores and production of the same.

Abstract: Filter apparatus having a honeycomb structure and a heater for purifying exhaust gases consists of cells or passages defined by porous partition walls. Alternate passages are provided respectively with upstream plugs and downstream plugs. Particulates in exhaust gases are trapped in the honeycomb structure and ignited by the heater. The upstream plugs define spaces upstream thereof in which particulates are trapped in addition to those trapped in the passages having downstream plugs. The heat of burning of the particulates trapped in the spaces facilitates the burning of the particulates trapped in the passages having downstream plugs. Therefore, the exhaust gas particulates trapped and collected in the downstream portion of the structure can also be easily burned to regenerate the structure over its entire length.

Abstract: A method of manufacturing a porous ceramic body useful for a catalyst carrier or a filter which comprises preparing a ceramic honeycomb structure having passages, filling a ceramic slurry mixed with organic solids into the passages and then baking the whole ceramic body to gasify the organic solids thereby producing fine meandering holes in the passages. A porous ceramic body produced by such a method is also proposed.

Abstract: An analytical composition comprises glucokinase and glucose-6-phosphate dehydrogenase.

Abstract: A process for producing a cordierite ceramic product comprises blending a starting cordierite composition which comprises:(a) a clay formulation having a cordierite composition comprising kaolin, talc and aluminium oxide and/or an aluminium compound which is convertible into aluminium oxide;(b) a glass having a cordierite composition;(c) an organic binder; and,(d) water.

Abstract: A gas sensor is disclosed which comprises a sintered metal oxide the resistance value of which changes with the ambient temperature, a gas sensor element having at least one electrode connected to the sintered metal oxide, a ceramic insulator for insulatively holding the gas sensor, a lead connection and a lead wire connected between the electrodes. The diameter of the ceramic insulator for passing the lead wire is reduced and the length of the electrode is shortened, thus realizing a compact gas sensor.

Abstract: A method and composition for use therein for measuring the activity of creatine kinase (hereinafter referred to as "CK") having good storage stability is disclosed. More particularly, a composition for measurement of CK activity which comprises as main components phosphoglycerate kinase (hereinafter referred to a "PGK") which catalyzes the following reaction 2 and glyceraldehyde-3-phosphate dehydrogenase (hereinafter referred to as "GAPDH") which catalyzes the following reaction 3. Reaction 1 is catalyzed by the creatine kinase.Reaction 1Creatinephosphate+Adenosine-5'-diphosphate (hereinafter referred to as "ADP").revreaction.Creatine+Adenosine-5'-triphosphate (hereinafter referred to as "ATP")Reaction 2ATP+3-Phosphoglycerate.revreaction.ADP+1,3-DiphosphoglycerateReaction 31,3-Diphosphoglycerate+Reduce .beta.-nicotinamideadenine dinucleotide (hereinafter referred to as "NADH").revreaction.Glyceraldehyde-3-phosphate+.beta.

Abstract: This invention relates to a process for producing collagenase, which comprises aerobically cultivating a collagenase-producing bacterium belonging to the genus Bacillus, and recovering collagenase from the culture broth.This invention also provides a thermophilic bacterium of the genus Bacillus which has the ability to produce collagenase and which grows at a temperature of 42.degree. to 74.degree. C. and a pH of 5.0 to 9.0 and a novel thermophilic collagenase which does not substantially lose collagenase activity even when maintained for 1 hour at a temperature of 60.degree. C. in the presence of a calcium ion at a pH in the range of 6.5 to 8.5, and which has a molecular weight, determined by gel filtration, between those of cytochrome C and ovalbumin.

Abstract: An oxygen concentration sensing apparatus in which a block of an oxygen-ion conductive solid electrolyte is interposed between a first electrode and a second electrode disposed opposite to each other. The first electrode is made of a catalytic metal and is exposed at a portion thereof on a surface of the solid electrolyte block, and an electrical insulating heat-resistive layer having a plurality of communication pores covers the exposed portion of the first electrode. The second electrode is porous and made of a catalytic metal. The solid electrolyte is wholly exposed to a stream of gases containing oxygen whose concentration is to be measured, and during measurement, a current source supplies continuously an electric current in a direction from the first electrode toward the second electrode.

Abstract: In an oxygen concentration sensing apparatus comprising a solid, oxygen ion conductive, electrolyte and intervening between two electrodes to generate across the two electrodes a potential difference due to a difference in oxygen concentrations at the boundaries between the two electrodes and the solid electrolyte, one of the two electrodes is made of a metal performing catalytic action, one end portion of the one electrode is embedded in the solid electrolyte to be fixed thereby, the other end portion of the one electrode projects outwardly of the solid electrolyte, a portion of the one electrode contacting with an outer surface of the solid electrolyte is hermetically sealed with a nonconductive layer of a heat-resistant material, and the other electrode is made of a porous metal performing catalytic action and is disposed on the outer surface of the solid electrolyte but preventing the other electrode from being in contact with the one electrode.