Abstract: In a gas sensor which uses CuO as a p-type semiconductor, by adding Na.sub.2 CO.sub.3 in excess of 1 wt % relative to CuO, sensitivity to gases such as H.sub.2, NO, NO.sub.2 and SO.sub.2 is suppressed, whereby selectivity for CO is increased. Sensitivity to CO.sub.2 can also be obtained. In addition, by adding a sodium salt of tungstic acid or molybdic acid, CO.sub.2 sensitivity can be made lower than the CO sensitivity, and CO gas in the exhaust gases discharged from gas-fired water heaters or other combustion equipment can be selectively detected. It is therefore possible to detect incomplete combustion.

Abstract: P-type semiconductor 15 and n-type semiconductor 16 are formed as thick films or spray-coated onto electrodes 13 and 14 on top of substrates 11 and 12, with films of p-type semiconductor 15 and n-type semiconductor 16 being formed in such manner that they are in mutual contact. If a gas to be detected is introduced to the contact region while a bias voltage is being applied between the two electrodes, an output will be obtained in accordance with the concentration of flammable gas components in the gas being detected. In addition, if a film is formed from a material comprising a mixture of particles of p-type semiconductor and particles of n-type semiconductor, the bias voltage can be an AC voltage.

Abstract: This invention concerns a humidity sensor wherein a chemical conversion coating, giving attention to the property that it undergoes an impedance decrease with adsorption of moisture, is used as humidity sensing element which is characterizied by an extremely short electrode distance, greatly improved sensitivity, high speed response, stable performance over a long period of time, high reliability and cheaper production cost.The principal point that characterizes the humidity sensor in this invention is that the chemical conversion coating deposited on the metal surface with or without an electrolysis application, is made usable as a humidity sensing element. For the chemical conversion coating, such coatings as phosphate, oxalate, titanium fluoro-complex, chromium phosphate and non-chromium types are used.On top of this chemical conversion coating, application of a humidity sensing film is effected to further improve humidity sensing performance.

Abstract: A resistance element causing less sliding noise for use in wound-type variable resistors and a method of making the same are disclosed. A resistance element obtained by winding a metallic resistance wire on a core is subjected to etching treatment. With this etching treatment, the metallic oxides, chlorides and sulfides considered acting as insulators, and organic molecules, adsorbed gases and other contamination forming the surface layer of the resistance wire are dissolved and removed. Furthermore, by immersing the etched resistance element in an ammonia solution, etc., the copper precipitated on the surface of the resistance wire is dissolved.

Abstract: A metallic coating method is carried out by contacting a surface of a substrate with a molten metal which is locally raised under ultrasonic vibration. A metallic coating can be continuously attained on one side only of ribbon type substrate in a form of plate, sheet or strip or only the outer surface of a pipe.

Abstract: A humidity sensor comprising a pair of spaced electrodes on an insulating substrate is formed by coating an orthophosphate as a sensitive membrane over at least a portion of the gap between the electrodes.

Abstract: An apparatus is provided for automatically sealing insulation tubes comprising a turn table intermittently turned through a part of a revolution and having a plurality of tube holders disposed in a circle about its central axis, a friction wheel disposed below the turn table and engaging the tube holders for rotating them about their respective vertical axes, a mechanism for stopping the rotation of a predetermined number of the tube holders at predetermined positions along the path of revolution of the turn table, a device for heating the tubes at predetermined positions along the path of revolution of the turn table and a mechanism for supplying a molten solder to the holders being rotated about their axes at a predetermined position in the revolution of the turn table whereby the molten solder is distributed to the peripheral parts of the tube.

Abstract: Difficultly solderable material having an oxide surface such as glass, ceramics or such metals as Si, Ge, Al, Ti, Zr or Ta is soldered using a solder alloy composed of 2-98.5% by wt. of Pb, 1-97.5% by wt. of Sn and 0.1-15% by wt. of rare earth metals, while applying vibration, preferably of the ultrasonic type.