The Standard Oil Company

The Standard Oil Company (ohio)

Stephen C Pyke

Donald L Boos

Mark R Bruce

Milton L Brouwer

Michael T McMahon

Lightweight, compact apparatus for detecting sudden changes in the concentration of at least one selected gas provides a warning when said gas concentration increases suddenly. In one embodiment, a chemically sensitive field effect transistor provides a sensing signal two amplifiers having different overall gains and widely different time constants. Detection of sudden gas concentration changes causes the relative magnitudes of the amplifier output signals to be inverted triggering a warning. The apparatus may occupy less than 1.25 cubic inches and weigh less than 4 ounces so that it may be worn by an individual throughout his work place.

Lightweight, compact detector of sudden changes in concentration of a gas

The use of multiple field effect transistors, wherein only one transistor is sensitive to the presence of a particular element, is disclosed whereby similar responses to temperature and/or humidity fluctuations may be subtracted yielding a response to a particular element that is relatively insensitive to temperature and/or humidity variations.

Temperature and humidity compensation for gas detection apparatus

A method is disclosed for forming a chemically sensitive field-effect transistor having a suspended gate which enables the uniform and reproducible manufacture of such devices. Controlled uniformity and device response is provided by this method which makes the field-effect transistors suitable for use as sensors, alarms and analyzers for gases. A method of regenerating a chemically sensitive field-effect transistor having a suspended gate is also disclosed.

Method of forming suspended gate, chemically sensitive field-effect

A semiconductor photoelectrode resistant to photocorrosion and a method of preparing such a photoelectrode are disclosed. The photoelectrode includes a doped oxide layer on which illumination falls for photo-stimulation. The oxide layer is doped with metallic ions, such as tantalum ions, to suppress photocorrosion. In one oxide doping method, tantalum pentachloride vapor generated by sublimation is directed against a silicon dioxide layer on a heated photoelectrode.

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Willowick, OH, United States of America

Stephen C Pyke