Abstract: Siloxane compounds are removed from the atmospheres by silica supporting an organic sulfonic acid compound. The silica with the organic sulfonic acid compound has a specific surface area down to 500 m2/g and up to 750 m2/g and a pore volume down to 0.8 m3/g and up to 1.2 m3/g, both measured by nitrogen gas adsorption method and has a pore diameter down to 4 nm and up to 8 nm, at the peak of differential pore volume measured by nitrogen gas adsorption method. The durability of gas sensing element against siloxanes is improved.

Abstract: The MEMS type semiconductor gas detection element of the invention is a MEMS type semiconductor gas detection element 1 having a MEMS structure, for detecting hydrogen gas, comprising: a substrate 2; a gas sensitive portion 3 mainly made of a metal oxide semiconductor and provided to the substrate 2; a heating portion 4 for heating the gas sensitive portion 3; an inactive film 5 having hydrogen-permselective and formed outside the gas sensitive portion 3; a protective film 6 formed outside the inactive film 5, for suppressing deterioration of the gas sensitive portion 3.

Abstract: A gas detector comprises a gas detection unit and a filter introducing surrounding atmosphere to the gas detection unit. The filter comprises a gas-permeable organic polymer membrane having an acidic group or a basic group.

Abstract: The present invention provides a catalytic conversion-type sensor that detects a detection target gas by detecting a conversion gas produced through a reaction, the catalytic conversion-type sensor including: a gas flow path that allows the detection target gas to flow down; and a conversion portion that is connected to the gas flow path, the conversion portion including, on a side partitioned by a diffusion means that allows the detection target gas to naturally diffuse, a heated catalyst portion that produces a conversion gas by causing the detection target gas to come into contact with a heated catalyst and react with the heated catalyst, and a sensor element portion that is capable of detecting the conversion gas produced through the reaction.

Abstract: The present invention provides a catalytic conversion-type sensor that detects a detection target gas by detecting a conversion gas produced through a reaction, the catalytic conversion-type sensor including: a gas flow path that allows the detection target gas to flow down; and a conversion portion that is connected to the gas flow path, the conversion portion including, on a side partitioned by a diffusion means that allows the detection target gas to naturally diffuse, a heated catalyst portion that produces a conversion gas by causing the detection target gas to come into contact with a heated catalyst and react with the heated catalyst, and a sensor element portion that is capable of detecting the conversion gas produced through the reaction.

Abstract: A controlled potential electrolysis gas sensor including, as gas electrodes 10 for detecting gas, a working electrode for electrochemically reacting gas to be detected, a counter electrode with respect to the working electrode, and a reference electrode for controlling potential of the working electrode, the gas electrodes 10 being disposed to face an electrolysis solution accommodating portion of an electrolysis tank accommodating electrolytic solution 20. Each electrode 10 includes a noble metal catalyst layer 50. On the noble metal catalyst layer 50 of at least one of the working electrode and the reference electrode, there is formed a polymer layer 60 having ion conductivity and water permeability.

Abstract: A controlled potential electrolysis gas sensor including, as gas electrodes 10 for detecting gas, a working electrode for electrochemically reacting gas to be detected, a counter electrode with respect to the working electrode, and a reference electrode for controlling potential of the working electrode, the gas electrodes 10 being disposed to face an electrolysis solution accommodating portion of an electrolysis tank accommodating electrolytic solution 20. Each electrode 10 includes a noble metal catalyst layer 50. On the noble metal catalyst layer 50 of at least one of the working electrode and the reference electrode, there is formed a polymer layer 60 having ion conductivity and water permeability.

Abstract: A method of determining a concentration of magnetic powderly material in a sample is disclosed. In this method, a pair of series-connected exciting coils are disposed in such a manner that magnetic fields generated from the respective exciting coils oppose to each other. A detecting coil is disposed at a position where the magnetic fields from the pair of exciting coils cancel out each other. A sample mixed with magnetic powder is inserted into one of the pair of exciting coils. Then, the method detects a voltage induced in the detecting coil in association with the insertion of the sample into the exciting coil and determines the concentration of the magnetic powder in the sample based on the detected voltage.

Abstract: A gas detecting method and apparatus for selectively detecting a fuel gas having methane as a main component thereof and an incomplete combustion gas having carbon monoxide as a main component thereof. A low heat capacity, hot-wire semiconductor type gas sensor used has an oxide semiconductor formed mainly of valency-controlled tin oxide and acting as a sensitive section thereof. An inactive to gas combustion, heat resistant, quadrivalent metallic oxide is mixed into the sensitive section. The sensitive section is alternately switched between a fuel gas detecting temperature and an incomplete combustion gas detecting temperature.

Abstract: The invention relates to a gas sensor comprises a precious metal electrode, a semiconductor layer entirely or partly covering the precious metal electrode, a barrier layer having a high potential formed at an interface between the precious metal electrode and the semiconductor layer.

Abstract: A method of measuring the quantity of an admixture in ready-mixed concrete comprises the steps of collecting volatile components generated from the admixture, measuring the concentration of the collected volatile components, and deriving the quantity of the admixture in the ready-mixed concrete from the measured concentration of the volatile components. An apparatus for executing this method comprises a detecting probe and a main measuring unit. The probe includes a gas collecting section and a gas sensor. The main measuring unit for carrying out arithmetic operations on detection information received from the detected probe, and includes a controller for microprocessor the operation of the entire apparatus, and a display for displaying the detected information received from the microprocessor.

Abstract: A smell sensing element and a smell sensing device utilizing the element. The smell sensing element has a semiconductor portion formed mainly of SnO.sub.2. The semiconductor portion has a first component of at least one selected from the group consisting of oxides of alkaline earth metals and a second component of at least one selected from the group consisting of oxides of Sc, Y, Ti, Zr, Hf, Th, Al, Ga and lanthanoids added thereto.

Abstract: An ozone gas sensor comprising a film type semiconductor element including a substrate and a semiconductor film consisting of a metallic oxide formed on the substrate, and a layer of silica formed on a surface of the film type semiconductor element. At least one thin film layer of one or a plurality of types selected from metals and metal oxides is interposed between the semiconductor film and the layer of silica.

Abstract: An alcohol selective gas sensor including a detecting electrode and a semiconductor detecting element in contact with the detecting electrode, the semiconductor detecting element comprising tin oxide (SnO.sub.2) and a metal oxide of at least one of alkaline earth metals (Be, Mg, Ca, Sr, Ba) carried by the tin oxide, the metal oxide being contained in an amount of about 0.5 mol % or above.

Abstract: A gas senor having two terminals and comprising a heater having a positive temperature coefficient of resistance and a gas sensitive semiconductor covering the heater, connected to the heater at least at their opposite ends and having a negative temperature coefficient of resistance. The coefficients of the heater and the semiconductor are so selected as to offset each other in such a manner that a combined resistance of said heater and said semiconductor is maintained substantially constant at operation temperatures.

Abstract: A hydrogen-selective gas sensor comprising a gas-sensing element including a semiconductor in a principal portion thereof, and a thin coat or layer inactive for oxidation of hydrogen formed over an entire surface of the gas-sensing element or at least on a surface of the semiconductor. The thin layer comprises one of silicon oxide, aluminum oxide, and silicon nitride, and is formed on the surface of the semiconductor by chemical deposition, the thin layer checking passage of molecules other than hydrogen molecules.

Abstract: A gas sensor comprising a sintered piece composed of tin oxide, at least one of lanthanide oxides and at least one of IVa group element oxides. The sintered piece may be covered or coated with a porous layer of a ceramic material such as silica, alumina or silica-alumina.

Abstract: A gas sensor comprising a layer of sintered tin oxide having a large specific surface area and high activity to oxidize and eliminate alcohol, benzene and other miscellaneous gases, whereby the sensor selectively detects alkane gases such as methane gas, propane gas and butane gas. The alkane gas is absorbed thereby decreasing an electrical resistance of the sensor in order to detect the existence of the gas.