Abstract: A gas sensor includes a measurement gas chamber into which a measurement gas is introduced. An oxygen pumping cell adjusts an oxygen concentration in the measurement gas chamber. An oxygen monitor cell has a monitor electrode exposed in the measurement gas chamber. The monitor electrode has an oxidizing activity with respect to a specific component of the measurement gas. A sensor cell has a sensor electrode exposed in the measurement gas chamber. The sensor electrode has an oxidizing activity with respect to the specific component of the measurement gas which is lower than the oxidizing activity of the monitor electrode. An oxygen-ion current in the oxygen monitor cell is detected. An oxygen-ion current in the sensor cell is detected. A concentration of the specific component of the measurement gas is detected from a relation between the detected oxygen-ion currents in the oxygen monitor cell and the sensor cell.

Abstract: The oxygen concentration detector of the present invention includes a sensor element having a solid electrolyte and having an external electrode and an internal electrode provided on the external surface and the internal surface, respectively, and a heater provided adjacent to the internal surface of the sensor element, in which a high-emissivity layer consisting of a material having a high emissivity is provided on the internal surface of the sensor element and/or the surface of the heater.

Abstract: A NOx sensing cell includes a solid electrolyte having oxide ion conductivity and a pair of electrodes electrically connected to the solid electrolyte. The measuring electrode includes an oxide portion and a noble metallic portion. The oxide portion includes the solid solution of zirconia containing at least ceria. The noble metallic portion contains at least two kinds of metallic elements selected from platinum group elements. In addition to the NOx sensing cell, a NOx sensing device includes a measuring chamber into which a sensing objective gas is introduced, and an oxygen pump cell which is capable of electrochemically removing the oxygen from the measuring chamber. The measuring electrode of the NOx sensing cell is positioned in the measuring chamber.

Abstract: In order to raise accuracy of measurement, a compound layered type of sensing device is provided. The device comprises a plurality of solid electrolyte plates and first to third electrochemical cells. Each cell has a single pair of electrodes disposed on the solid electrolyte plates. A concentration of a gas specified from a gas to be measured pre-processed based on oxygen pumping by the first electrochemical cell is detected by the second electrochemical cell. A difference in electromotive force between the gas to be measured and a reference gas is detected by the third electrochemical cell. The single pair of electrodes of the third electrochemical cell is disposed on the same surface of one of the solid electrolyte plates, and both of the first and third electrochemical cells are located with different ones of the solid electrolyte plates.

Abstract: A NOx gas detecting apparatus including an oxygen pumping cell for removing oxygen from a measurement gas, and a NOx detecting cell positioned downstream from the oxygen pumping cell to detect concentration of NOx in the measurement gas, the NOx detecting cell being configured to measure current which flows when oxygen generated from reducing NOx is pumped, wherein the NOx detecting cell has a NOx detecting cathode made of an electrode material including at least one alloy selected from the group consisting of a Pt-Pd alloy, a Pt-Au-Pd alloy, and a Pt-Pd-Rh alloy.

Abstract: An objective gas to be measured is introduced into first and second chambers which are connected via a diffusion resistive passage. A first electrochemical cell is provided in the first chamber for pumping in and out oxygen in accordance with an applied voltage. A second electrochemical cell is provided in the second chamber and responsive to application of a predetermined voltage for generating a sensor current representing a specific gas concentration in the objective gas. The first electrochemical cell is located between the first chamber and a reference gas chamber so that oxygen pumping in and out operation can be performed between the first chamber and the reference gas chamber.

Abstract: An exhaust gas side electrode is provided on one surface of a solid electrolytic substrate. A reference gas side electrode is provided on an opposite surface of the solid electrolytic substrate so as to be exposed to a reference gas stored in a reference gas chamber. Each lead of the electrode is connected to a signal output terminal. This sensor satisfies a relationship B/A<0.5, wherein ‘A’ represents an overall resistance value of an electric path including the solid electrolytic substrate, the electrodes, and their leads in a sensor activated condition, while ‘B’ represents a resistance value of the leads at a room temperature. Some embodiments may be arranged such that at least one of the leads has a low resistance portion located in the vicinity of the electrodes and a high resistance portion located in the vicinity of signal output terminals.

Abstract: An objective gas is successively introduced into first and second chambers which are connected via a narrow passage. A first monitor cell, provided on a surface of the first chamber, generates an electromotive force representing an oxygen concentration in the first chamber. A second monitor cell, provided on a surface of the second chamber, generates an electromotive force representing an oxygen concentration in the second chamber. A voltage applied to a pump cell is controlled based on the electromotive forces obtained from the first and second monitor cells.

Abstract: A gas sensor includes a measurement gas chamber into which a measurement gas is introduced. An oxygen pumping cell adjusts an oxygen concentration in the measurement gas chamber. An oxygen monitor cell has a monitor electrode exposed in the measurement gas chamber. The monitor electrode has an oxidizing activity with respect to a specific component of the measurement gas. A sensor cell has a sensor electrode exposed in the measurement gas chamber. The sensor electrode has an oxidizing activity with respect to the specific component of the measurement gas which is lower than the oxidizing activity of the monitor electrode. An oxygen-ion current in the oxygen monitor cell is detected. An oxygen-ion current in the sensor cell is detected. A concentration of the specific component of the measurement gas is detected from a relation between the detected oxygen-ion currents in the oxygen monitor cell and the sensor cell.

Abstract: An exhaust gas side electrode is provided on one surface of a solid electrolytic substrate. A reference gas side electrode is provided on an opposite surface of the solid electrolytic substrate so as to be exposed to a reference gas stored in a reference gas chamber. Each lead of the electrode is connected to a signal output terminal. This sensor satisfies a relationship B/A <0.5, wherein ‘A’ represents an overall resistance value of an electric path including the solid electrolytic substrate, the electrodes, and their leads in a sensor activated condition, while ‘B’ represents a resistance value of the leads at a room temperature.

Abstract: An objective gas is successively introduced into first and second chambers which are connected via a narrow passage. A first monitor cell, provided on a surface of the first chamber, generates an electromotive force representing an oxygen concentration in the first chamber. A second monitor cell, provided on a surface of the second chamber, generates an electromotive force representing an oxygen concentration in the second chamber. A voltage applied to a pump cell is controlled based on the electromotive forces obtained from the first and second monitor cells.

Abstract: An underwater laser television, which radiates laser pulses, output from a laser oscillator, to a visualized object under water and detects reflection light of the laser pulses to display an image of the visualized object, is constructed by a main body which is located under water to have a capability of free movement and to resist against the water pressure and which provides a light transmission portion for transmitting the laser pulses and reflection light, the laser oscillator arranged inside of the main body, radiation and light receiving means, arranged in the main body, which radiates the laser pulses toward the visualized object and detects the reflection light to produce video signals of the visualized object, and display means, arranged in the main body, which displays an image of the visualized object based on the video signals.

Abstract: In order to raise accuracy of measurement, a compound layered type of sensing device is provided. The device comprises a plurality of solid electrolyte plates and first to third electrochemical cells. Each cell has a single pair of electrodes disposed on the solid electrolyte plates. A concentration of a gas specified from a gas to be measured pre-processed based on oxygen pumping by the first electrochemical cell is detected by the second electrochemical cell. A difference in electromotive force between the gas to be measured and a reference gas is detected by the third electrochemical cell. The single pair of electrodes of the third electrochemical cell is disposed on the same surface of one of the solid electrolyte plates, and both of the first and third electrochemical cells are located with different ones of the solid electrolyte plates.

Abstract: An objective gas to be measured is introduced into first and second chambers which are connected via a diffusion resistive passage. A first electrochemical cell is provided in the first chamber for pumping in and out oxygen in accordance with an applied voltage. A second electrochemical cell is provided in the second chamber and responsive to application of a predetermined voltage for generating a sensor current representing a specific gas concentration in the objective gas. The first electrochemical cell is located between the first chamber and a reference gas chamber so that oxygen pumping in and out operation can be performed between the first chamber and the reference gas chamber.

Abstract: Disclosed is a NOx gas detecting apparatus which is capable of detecting a NOx gas at a low concentration with high accuracy over a long period of time even if Au or impurities contained in exhaust gas adheres to a cathode of a NOx detecting cell, and which is excellent in startability and responsivity. The NOx detecting apparatus comprises an oxygen pumping cell for removing oxygen from a measurement gas, and a NOx detecting cell. The NOx detecting cell includes, as a cathode, a cermet electrode composed of a Pt-Pd alloy, a Pt-Au-Pd alloy, or a Pt-Pd-Rh alloy along with a ceramic component. An addition amount of Pd to the alloy is preferably from 1 to 90 wt %. A weight ratio of Pd to Au in the Pt-Au-Pd alloy is preferably not less than 1.67. An addition amount of Rh in the Pt-Pd-Rh alloy is not more than 30 wt %.

Abstract: An oxygen sensor element includes a solid electrolyte having cavities on a surface thereof and an electrode formed on the surface of the solid electrolyte. In a method of producing the oxygen sensor element, a solution containing a noble metal compound for nucleus formation is first applied to an electrode forming portion of the solid electrolyte to form a coating film. Then, the coating film is heat-treated to form a nucleus forming portion where noble metal nuclei are deposited. Subsequently, metal plating is applied to the nucleus forming portion to form a plating film deeply entering the cavities. Thereafter, the plating film is burned to form the electrode deeply entering the cavities.

Abstract: A method for manufacturing an oxygen sensor unit of the type which includes at least a shaped body of a solid electrolyte, an inner electrode provided on an inside surface of the shaped body and exposed to a reference gas, an outer electrode provided on an outside surface of the shaped body and exposed to a gas to be measured, and a porous protective layer covering the outer electrode and a portion of the shaped body adjoining to said outer electrode wherein the solid electrolyte is made of a mixture of zirconia and a stabilizer therefor and is constituted of a sintered product of partially stabilized zirconia. The method is characterized in that the partially stabilized, sintered zirconia is obtained according to a high temperature sintering process which includes at least the step of sintering the mixture at a temperature of 1200° C.

Abstract: A simulation method for imaging of an underwater object is performed by simulating the object with a test panel having several strips of different brightness, and irradiating the test panel with a pulsed laser beam having three primary colors. From the reflected beam pulses, contrast values of the test stripes are computed for reflected pulses of each color in relation to the turbidity and visibility distance. The method may be used in conjunction with an imaging apparatus having a laser generation device which produces three primary colors of three different wavelengths; a laser beam detection device to receive the reflected beam pulses of respective primary colors, to determine intensities of the reflected beam pulses of respective primary colors, and to output three primary color signals to an image monitoring device.

Abstract: An oxygen sensor element includes a solid electrolyte having cavities on a surface thereof and an electrode formed on the surface of the solid electrolyte. In a method of producing the oxygen sensor element, a solution containing a noble metal compound for nucleus formation is first applied to an electrode forming portion of the solid electrolyte to form a coating film. Then, the coating film is heat-treated to form a nucleus forming portion where noble metal nuclei are deposited. Subsequently, metal plating is applied to the nucleus forming portion to form a plating film deeply entering the cavities. Thereafter, the plating film is burned to form the electrode deeply entering the cavities.

Abstract: An air-fuel ratio sensing element comprises a cup-shaped solid electrolyte with one end opened and the other end closed, an external electrode provided on an outer wall surface of the solid electrolyte so as to be exposed to measured gas, and an internal electrode provided on an inner wall surface of the solid electrolyte in a confronting relationship to the external electrode. A first insulating layer, made of a gas-permeable and nonconductive porous material, is provided on the external electrode at least in a region used for detecting of an air-fuel ratio. A second insulating layer is provided outside the first insulating layer and, a heater layer as provided between the first insulating layer and the second insulating layer.