Abstract: A flowing junction reference electrode exhibiting heretofore unattainable potentiometric characteristics is described, comprising a microfluidic liquid junction member that is situated between a reference electrolyte solution and a sample solution. This microfluidic liquid junction member has an array of nanochannels spanning the member and physically connecting the reference electrolyte solution and a sample solution, but while the electrolyte solution flows through the array of nanochannels and into the sample solution at a linear velocity, the sample solution does not substantially enter the array of nanochannels via the mechanisms of diffusion, migration, convection or other known mechanisms. The number of nanochannels in the array is preferably between approximately 108 and approximately 10. Also preferably, the nanochannels are substantially straight and are substantially parallel to one another; such an array of nanochannels is herein described as anisotropic.

Abstract: An electrochemical sensor for ascertaining gas concentrations in gases, particularly in exhaust gases of combustion engines, includes an oxygen-ion-conductive solid electrolyte which is provided with electrode layers arranged at a distance from one another and with at least one resistance heating element that is separated from the solid electrolyte by an electrical insulating layer, a foil binder layer being provided between the electrical insulating layer and the solid electrolyte. At least one electron-conductive intermediate layer is provided between the electrode-side electrical insulating layer and the adjacent solid electrolyte.

Abstract: A prismatic ceramic heater for heating a gas sensor element includes a heating resistor embedded in ceramic, and has a substantially rectangular cross section. At least part of a longitudinally extending edge portion of the prismatic ceramic heater is located in the vicinity of the heating resistor. This part of the longitudinally extending edge portion is coated with a porous protective layer. The protective layer has a thickness not less than 20 &mgr;m and a curved surface of a curvature radius not less than 10 &mgr;m. The protective layer prevents cracking induced by contact with water.

Abstract: A method for determining a urea concentration in an aqueous solution containing urea, includes: hydrolyzing the urea in the aqueous solution, measuring an electric conductivity &khgr; of the aqueous solution, and determining the urea concentration in the aqueous solution from the electric conductivity &khgr; using a correlation between the urea concentration and an electric conductivity.

Abstract: A gas concentration measuring apparatus which has a gas sensor designed to measure, for example, the concentrations of O2 and HOx contained in exhaust emissions of an automotive engine is provided. The apparatus includes a signal processing circuit which converts a current signal outputted from the gas sensor as a function of the concentration of either of O2 and HOx into a voltage signal. The gas sensor and the signal processing circuit are connected electrically through a conductor. The conductor has a length which is determined as a function of a level of the current signal outputted from the gas sensor. The weaker the level of the current signal is, the shorter the length of the conductor. This minimizes addition of electrical noises to the current signal outputted from the gas sensor.

Abstract: A flowing junction reference electrode exhibiting heretofore unattainable potentiometric characteristics is described, comprising a microfluidic liquid junction member that is situated between a reference electrolyte solution and a sample solution. This microfluidic liquid junction member has an array of nanochannels spanning the member and physically connecting the reference electrolyte solution and a sample solution, but while the electrolyte solution flows through the array of nanochannels and into the sample solution at a linear velocity, the sample solution does not substantially enter the array of nanochannels via the mechanisms of diffusion, migration, convection or other known mechanisms. The number of nanochannels in the array is preferably between approximately 108 and approximately 100. Also preferably, the nanochannels are substantially straight and are substantially parallel to one another; such an array of nanochannels is herein described as anisotropic.

Abstract: A low cost amperometric oxygen sensor which utilizes a plurality of oxygen ion conductor layers interposed between a plurality of oxygen-porous electrode layers is provided. Oxygen from a sample gas enters the sensor at porous cathode electrodes, is pumped through the ion conductor layers, and exits through the anode electrodes. The amperometric current generated is representative of the partial pressure of oxygen in the sample gas. In accordance with one embodiment of the present invention, an amperometric oxygen sensor is provided for determining the oxygen partial pressure of a gas. The sensor comprises a sensor body defined by a plurality of oxygen-porous electrode layers and at least one oxygen ion conductor layer. The plurality of oxygen-porous electrode layers include at least one cathode layer and at least one anode layer. Each of the cathode layers define first and second major cathode surfaces and each of the anode layers defining first and second major anode surfaces.

Abstract: In a maltilayer exhaust gas component sensor for measuring NOX (nitrogen oxide) and HC (hydrocarbon), the reliability and the productivity are improved without degrading the detecting sensitivity. A gas sensing portion is formed by laminating porous solid electrolyte layers having gas permeability together with an electrode protecting film, porous electrodes having catalytic activity, a porous electric insulating layer and a closely-compacted (dense) solid electrolyte layer, and by placing a heater as a temperature control means in contact with or near the laminated layer body.

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: The invention presents a hydrocarbon sensor excellent in yield and high in detection precision. To achieve the object, the invention includes a solid electrolyte layer (1) contained barium-cerium oxide, a pair of electrodes, cathode (2) and anode (3), provided on the solid electrolyte layer (1), a ceramic substrate (4) having a coefficient of thermal expansion nearly same as that of the solid electrolyte layer (1), and a heater (7) provided on the ceramic substrate (4), in which the solid electrolyte layer (1) and ceramic substrate (4) are bonded to each other.

Abstract: Apparatus for detecting the NOx concentration includes a first measurement chamber 20 communicating with the gas under measurement via a diffusion rate defining layer 4d and a second measurement chamber 26 communicating with the first measurement chamber 20 via diffusion limiting layers 6d, 22d. A first pump current IP1 is controlled so that an output of a Vs cell 6 will be equal to the reference voltage VCO for controlling the oxygen concentration in the first measurement chamber 20 to a pre-set low value. A constant voltage is applied across the second pump cell 8 for decomposing the NOx component in the second measurement chamber 26 for pumping out oxygen for detecting the NOx concentration from a second pump current IP2. The sensor temperature is detected from the internal resistance of the Vs cell for controlling the current supplied to the heaters 12, 14. If the temperature of the gas under measurement is changed rapidly, the sensor temperature is changed.

Abstract: A predetermined voltage is applied to a biosensor twice to promote an electrochemical reaction, and the following parameters (P1 and P2) are calculated from the values of detected current. A statistical technique is used with these parameters to compensate for errors so that the concentration of an object can be determined. P1: the ratio (If/Ib) of the maximum current (If) or a current occurring the maximum in the first excitation to a current (Ib) read at any point in the second excitation. P2: a current (Ib) read at any point in the second excitation.

Abstract: A reference electrode (1) for electrochemical measurements includes a metallic palladium-containing electrode component (3) which is covered by a layer (4) formed of or containing a palladium compound poorly soluble in aqueous media. Positioned on layer (4) is a reference electrolyte (5) which contains anions of this palladium compound in dissolved form (FIG. 4).

Abstract: A sensor determines the concentration of gas components in a gas mixture with at least one measuring electrode exposed to the gas mixture and a reference electrode and with a heating device for controlling the temperature of at least one measuring electrode and the reference electrode. A measurement signal taken off the at least one measuring electrode can be changed via a corrective value, which is dependent upon the heating power of the heating device necessary to reach a pregiven value of the heating resistance of at least one heating element of the heating device.

Abstract: In performing control to supply power to a heater by detecting the impedance of a sensor element and feeding it back for control, a heater control device for an air-fuel ratio according to the invention can prevent damage to the heater or the sensor element by suppressing an excessive rise in the temperature of the heater and hence the sensor element even when the impedance of the sensor element has increased due to degradation of the sensor element. The heater control device includes: a feedback control unit which, based on the impedance of the air-fuel ratio sensor element, controls supply power to the heater for heating the air-fuel ratio sensor; a half-activation time detection unit which detects the half-activation time of the air-fuel ratio sensor; and a power limiting unit which, based on the half-activation time detected by the half-activation time detection unit, limits the power that is feedback-controlled by the feedback control unit.

Abstract: An automatic electrophysiological measuring apparatus to automatically penetrate a glass electrode(s) into the membrane of a Xenopus Oocyte to hold the membrane potential and to automatically measure reactions to the administration of a medicine is to be provided. A glass electrode 103 in the air is moved toward a Xenopus Oocyte 601 held in a cell. Changes in the potential states of the glass electrodes are picked up by a control computer to distinguish the relative positions of the glass electrode 102 and the Xenopus Oocyte 601, and the sequence of electrophysiological measurement so as to penetrate the glass electrode 102 into the Xenopus Oocyte 601, hold the membrane potential and automatically administer the medicine.

Abstract: A method and system for controlling the temperature of an oxygen sensor is provided wherein the method includes obtaining an oxygen sensor, a heating device, heating control device and a signal generator, wherein the oxygen sensor includes a reference cell and wherein the heating device is communicated with the oxygen sensor and the heating control device, introducing a fixed frequency sinusoidal signal to the reference cell through a voltage divider resistor so as to create a response signal, wherein the response signal is responsive to the temperature of the reference cell, buffering the response signal so as to create a buffered signal, applying the buffered signal to a high pass filter so as to create a filtered signal having a filtered signal magnitude, wherein the filtered signal magnitude is inversely proportional to the temperature of the reference cell, measuring the filtered signal so as to create a temperature signal responsive to the filtered signal magnitude and communicating the temperature sign

Abstract: Apparatus for detecting the NOx concentration includes a first measurement chamber 20 communicating with the gas under measurement via a diffusion rate defining layer 4d and a second measurement chamber 26 communicating with the first measurement chamber 20 via diffusion limiting layers 6d, 22d. A first pump current IP1 is controlled so that an output of a Vs cell 6 will be equal to the reference voltage VCO for controlling the oxygen concentration in the first measurement chamber 20 to a pre-set low value. A constant voltage is applied across the second pump cell 8 for decomposing the NOx component in the second measurement chamber 26 for pumping out oxygen for detecting the NOx concentration from a second pump current IP2. The sensor temperature is detected from the internal resistance of the Vs cell for controlling the current supplied to the heaters 12, 14. If the temperature of the gas under measurement is changed rapidly, the sensor temperature is changed.

Abstract: A heater is inserted into an inside chamber of a sensor element until a tip end of the heater is surely brought into contact with a bottom surface of the inside chamber. Next, a metallic holder is attached on an outside surface of the heater. Then, the metallic holder is slid along the outside surface of the heater toward the bottom surface of the sensor element to engage the metallic holder with an edge of the sensor element.

Abstract: A device for water quality measurement apparatus includes a plurality of multi-element arrays formed on a substrate, which are immersed in a solution for detecting electroactive elements or compounds present in such a solution. A wafer is located between first and second ‘O’ rings, with the first ‘O’ ring being disposed on a first side of the wafer and the second ‘O’ ring being disposed on a second side of the wafer, opposite to the first side. The first and second ‘O’ rings are arranged such that the wafer is exposed to substantially equal pressure on both sides.

Abstract: A temperature controlling protection system for a heater of the wet etching device has a temperature controlling protection circuit and a heating ON/OFF controller, in which the temperature controlling circuit has an OR gate, an AND gate and a NOT gate. When the temperature controlling protection circuit receives signals from the wet etching device, such as a level signal for a level sensor, an overheated signal for a temperature sensor, a ON/OFF signal for an acid discharging switch, a protection signal and a caution signal for the heater 28 and output signal for a constant temperature controller, it is determined whether the heater of the wet etching device is actuated to provide heat to the reaction gas in the wet etching device.

Abstract: A gas sensor includes a sensor element. The sensor element has a solid electrolytic member, a measurement electrode, and a reference electrode. The measurement electrode is provided on the solid electrolytic member, and is exposed to a measurement gas. The reference electrode is provided on the solid electrolytic member, and is exposed to a reference gas. A heater operates for heating the sensor element. A portion of the heater contacts a portion of the sensor element. The temperature of the sensor element is increased to 300° C. by the heater in ten seconds after the start of activation of the heater.

Abstract: A heater control system is provided for controlling the temperature of a heater used to heat a solid electrolyte-made sensor element of a gas concentration sensor up to a given temperature at which the sensor element is activated to provide a correct gas concentration output for controlling a preselected variable used in, for example, an automotive air-fuel ratio control system. The heater control system measures a resistance value of the sensor element and controls an electric power supplied to the heater as a function of the resistance value. The heater control system is designed to determine a controlled variable properly used to control the heater, thereby resulting in improved controllability of a power supply to the heater and also works to minimize an error in determining the resistance of the heater.

Abstract: An automatic electrophysiological measuring apparatus to automatically penetrate a glass electrode(s) into the membrane of a Xenopus Oocyte to hold the membrane potential and to automatically measure reactions to the administration of a medicine is to be provided. A glass electrode 103 in the air is moved toward a Xenopus Oocyte 601 held in a cell. Changes in the potential states of the glass electrodes are picked up by a control computer to distinguish the relative positions of the glass electrode 102 and the Xenopus Oocyte 601 and the sequence of electrophysiological measurement so as to penetrate the glass electrode 102 into the Xenopus Oocyte 601, hold the membrane potential and automatically administer the medicine.

Abstract: A detector for an air/fuel ratio sensor, which is comprised of a structure formed by stacking an oxygen reference electrode, a dense zirconia solid electrolyte, a negative electrode, a porous zirconia solid electrolyte, a positive electrode and a porous protection film on one another, is formed over a ceramic substrate having a heater built therein. Thus, a combined air/fuel ratio sensor can be obtained which is operated in a short time (about 5 seconds or less) after power-on so as to comply with emission control applied immediately after startup and provides low power consumption and a high degree of reliability.

Abstract: A gas sensor is disclosed comprising an oxygen pump cell having at least one exterior pump electrode and at least one interior pump electrode disposed on opposite sides of a first solid electrolyte layer. An emf cell having a first and second emf electrodes and first and second reference gas electrodes are disposed on opposite sides of a second solid electrolyte layer. At least one insulating layer is in contact with the first and second emf electrodes. At least one via hole is disposed through the first solid electrolyte layer. At least one air channel is disposed through at least one insulating layer. An air vent is disposed in at least one insulating layer in contact with the first and second reference gas electrodes. A heater is disposed in thermal communication with the sensor. And at least five electrical leads are in electrical communication with said sensor. A method of using a gas sensor is also disclosed.

Abstract: An oxygen concentration detector comprises a solid electrolyte 21, a sensing element 2 which consists of the solid electrolyte 21 coated on the surface with an outer electrode 23, a heater 3 provided inside the solid electrolyte 21, and a protecting cover 16 which protects the sensing element 2. The protecting cover 16 has two levels of openings 161, 162, the outer electrode 23 is constructed within the range defined by the length of the heat-generating part 31 of the heater 3, and the relationship between the length L1 of the heat-generating part 31 and the distance between the openings L2 of the two levels of openings 161, 162 in the axial direction is such that L1/L2=0.9 to 1.3.

Abstract: A method of making a gas sensor is disclosed, comprising disposing an electrochemical cell comprising a sensing electrode and a reference electrode disposed in ionic communication with and on opposite sides of an electrolyte layer. A first insulating layer is disposed in contact with the sensing electrode. A second insulating layer is disposed in contact with the reference electrode. A first protective insulating layer and a first heater are disposed in contact and in thermal communication with the first insulating layer. A second protective insulating layer and a second heater are disposed in contact with and in thermal communication with the second insulating layer. The method includes forming a sensor and co-firing the sensor. A gas sensor is also disclosed as being made according to the above-referenced method.

Abstract: A sensor housing for accommodating at least one electrode which can be brought into contact with a process fluid, the sensor housing being sealable by means of a porous seal by which an inner chamber is formed between an inner surface of the sensor housing, the external surface of the at least one electrode and the surface of the porous seal, with the inner chamber being filled with a first electrolyte, wherein the sensor housing further comprises a deformable section which enables the inner chamber volume to be variable. The sensor housing may be used in a sensor which is temperature and pressure resistant over a wide range of values.

Abstract: Histamine may be quantitatively measured by performing the following steps. First, an oocyte that expresses histamine receptors is held in a recess formed at the bottom of a vessel. Then, first and second electrodes are inserted into the oocyte. Subsequently, the membrane potential of the oocyte is measured by using the first electrode to stabilize this membrane potential at a predetermined level by driving a current through the second electrode using circuitry for clamping the membrane potential of the oocyte. A sample is then infused into a fine reacting tube having an antigen immobilized on its inner surface together with some buffer solution to promote a histamine releasing reaction. The solution containing histamines that is released in the fine reacting tube is transferred to the vessel to make contact with the oocyte in the vessel.

Abstract: A nonfragile ad quickly activatable structure of a gas sensor element which may be built in a gas sensor employed in an air-fuel ratio control system for automotive vehicles for measuring the concentration of gas such O2, NOx, or CO. The gas sensor element is made of a lamination of a measurement gas electrode, a reference gas electrode, and a heater. The heater works to elevate the temperature of the gas sensor element up to a given value required to bring the gas sensor element into an activated condition. The heater includes a heater substrate, a heating element, and power supply leads. A minimum distance X between an edge of the heater substrate and an edge of the heating element meets a relation of 0.1 mm≦X≦0.6 mm, thereby minimizing a thermal expansion difference between the heater element and the heater substrate to avoid cracks in a portion of the heater substrate near the heater element.

Abstract: An A/F signal proportional to an oxygen concentration in the exhaust gas from an internal combustion engine is output upon application of a voltage based on an instruction from a microcomputer. At the time an element resistance is detected, a bias instruction signal Vr from the microcomputer is converted by a D/A converter 21 to an analog signal Vb. An output voltage Vc obtained by removing high frequency components from the analog signal Vb through an LPF 22 is input to a bias control circuit 40. During this time period in which the element resistance is detected, an accurate A/F signal is not output. Therefore, the A/F signal that has theretofore prevailed is held by a Sample/Hold circuit 70 to thereby prevent the use of an erroneous A/F signal. Namely, at the time of detecting the element resistance, the detected value of the oxygen concentration is prevented from becoming abnormal. As a result, an accurate A/F control can be executed using the detected element resistance.

Abstract: A gas sensor in the form of a mixed-potential sensor in which the influence of temperature-dependent interference is reduced. An improved temperature control is provided with the help of a temperature sensor mounted on the surface of the electrolytic substrate.

Abstract: A plate-shaped sensor element is proposed, in particular for determining the oxygen level in exhaust gases of internal combustion engines. The sensor element has at least one measuring cell with an oxygen-ion-conducting solid electrolyte and a heating element, the measuring cell and the heating element being connected with an electrical insulation layer. The material of the insulation layer is made of at least one crystalline, non-metallic material and at least one glass-forming material, a glazing filled with the crystalline, non-metallic material being formed when the sensor element is sintered.

Abstract: An A/F signal proportional to an oxygen concentration in the exhaust gas from an internal combustion engine is output upon application of a voltage based on an instruction from a microcomputer. At the time an element resistance is detected, a bias instruction signal Vr from the microcomputer is converted by a D/A converter 21 to an analog signal Vb. An output voltage Vc obtained by removing high frequency components from the analog signal Vb through an LPF 22 is input to a bias control circuit 40. During this time period in which the element resistance is detected, an accurate A/F signal is not output. Therefore, the A/F signal that has theretofore prevailed is held by a Sample/Hold circuit 70 to thereby prevent the use of an erroneous A/F signal. Namely, at the time of detecting the element resistance, the detected value of the oxygen concentration is prevented from becoming abnormal. As a result, an accurate A/F control can be executed using the detected element resistance.

Abstract: Histamine may be quantitatively measured by performing the following steps. First, an oocyte that expresses histamine receptors is held in a recess formed at the bottom of a vessel. Then, first and second electrodes are inserted into the oocyte. Subsequently, the membrane potential of the oocyte is measured by using the first electrode to stabilize this membrane potential at a predetermined level by driving a current through the second electrode using circuitry for clamping the membrane potential of the oocyte. A sample is then infused into a fine reacting tube having an antigen immobilized on its inner surface together with some buffer solution to promote a histamine releasing reaction. The solution containing histamines that is released in the fine reacting tube is transferred to the vessel to make contact with the oocyte in the vessel.

Abstract: Histamine may be quantitatively measured by performing the following steps. First, an oocyte that expresses histamine receptors is held in a recess formed at the bottom of a vessel. Then, first and second electrodes are inserted into the oocyte. Subsequently, the membrane potential of the oocyte is measured by using the first electrode to stabilize this membrane potential at a predetermined level by driving a current through the second electrode using circuitry for clamping the membrane potential of the oocyte. A sample is then infused into a fine reacting tube having an antigen immobilized on its inner surface together with some buffer solution to promote a histamine releasing reaction. The solution containing histamines that is released in the fine reacting tube is transferred to the vessel to make contact with the oocyte in the vessel.

Abstract: Histamine may be quantitatively measured by performing the following steps. First, an oocyte that expresses histamine receptors is held in a recess formed at the bottom of a vessel. Then, first and second electrodes are inserted into the oocyte. Subsequently, the membrane potential of the oocyte is measured by using the first electrode to stabilize this membrane potential at a predetermined level by driving a current through the second electrode using circuitry for clamping the membrane potential of the oocyte. A sample is then infused into a fine reacting tube having an antigen immobilized on its inner surface together with some buffer solution to promote a histamine releasing reaction. The solution containing histamines that is released in the fine reacting tube is transferred to the vessel to make contact with the oocyte in the vessel.

Abstract: Histamine may be quantitatively measured by performing the following steps. First, an oocyte that expresses histamine receptors is held in a recess formed at the bottom of a vessel. Then, first and second electrodes are inserted into the oocyte. Subsequently, the membrane potential of the oocyte is measured by using the first electrode to stabilize this membrane potential at a predetermined level by driving a current through the second electrode using circuitry for clamping the membrane potential of the oocyte. A sample is then infused into a fine reacting tube having an antigen immobilized on its inner surface together with some buffer solution to promote a histamine releasing reaction. The solution containing histamines that is released in the fine reacting tube is transferred to the vessel to make contact with the oocyte in the vessel.

Abstract: A method and apparatus for detecting a functional condition of an NOx occlusion catalyst using an NOx sensor. In order to compensate for variations in oxygen concentration of the exhaust gas which would otherwise affect the detected NOx concentration downstream of the NOx occlusion catalyst, a relative value is calculated as the difference between the detected NOx concentration and the value of the detected NOx concentration initially after start of operation control of an internal combustion engine at a lean air-fuel ratio. The occlusion capability of the NOx occlusion catalyst is judged to have deteriorated when an increase in the relative value exceeds a predetermined value. On the other hand, the NOx occlusion catalyst is judged to have suffered an anomaly when the rate of increase in the relative value becomes greater than a predetermined allowable value.

Abstract: A method of controlling and diagnosing the heater of a sensor sensitive to the composition of the exhaust gas of an engine; the sensor having at least an electrolytic cell sensitive to oxygen ions, and supplying information relative to the ratio of the mixture supplied to the engine; the method including the steps of: calculating an internal resistance value of the cell on the basis of detected values of the voltage at the terminals of the cell before and after supplying a reference current to the cell; correcting the calculated internal resistance value as a function of the detected ratio of the mixture supplied to the engine; converting the corrected internal resistance value into a current temperature value of the sensor; feedback controlling the temperature of the sensor by regulating the current supplied to the heater by processing the deviation between the current temperature value and an objective temperature; and diagnosing the efficiency of the heater as of the corrected internal resistance value of

Abstract: A gas sensor comprises a main pumping cell for pumping-processing oxygen contained in a first chamber, a feedback control system for comparing a partial pressure of oxygen in the first chamber with a first reference value to control the main pumping cell so that the partial pressure of oxygen has a predetermined value at which NO is not decomposable, an auxiliary pumping cell for pumping-processing oxygen in the second chamber, and a measuring pumping cell for pumping-processing oxygen produced by decomposition of NOx.

Abstract: A gas sensor is disclosed in order to decrease the offset value to a degree in which no trouble occurs in the measurement without causing any reduction of NOx so that the measurement accuracy for NOx is improved. In the gas sensor, NOx contained in a measurement gas introduced into a second chamber is decomposed by means of catalytic action and/or electrolysis to pumping-process oxygen produced by the decomposition so that NOx is measured on the basis of a pumping current flowing through a measuring pumping cell thereby. The gas sensor has the following pattern of a heater. That is, a minute pitch is provided for a pattern at a portion corresponding to the forward end of a sensor element, a coarse pitch is provided for a pattern at a central portion, and a pattern is removed at a portion corresponding to the backward end of the sensor element. Thus, the measuring pumping cell is allowed to have a resistivity of electronic conduction of not less than 1 M&OHgr; after conversion into a resistance value.

Abstract: The present invention provides processes for making stoichiometric, highly electrically resistant and crystalline gas-sensing layer of SnO2 thin-film for stable detection of reducing gases. It also provides processes for making stoichiometric and crystalline thin film CuO catalytic layer for the detection of dilute sulfur compound gases. The sensing layer is made using dual ion beam sputtering, where an argon ion beam sputters targets comprising Sn or its oxides, and a pure or highly concentrated oxygen ion beam is simultaneously deposited on a substrate. It also provides processes for making stoichiometric and crystalline thin film CuO catalytic layer for detection of dilute sulfur compound gases. The catalytic layer is made using dual ion beam sputtering, where an argon ion beam sputters targets comprising Cu or its oxides, and a pure or highly concentrated oxygen ion beam is simultaneously deposited on a substrate.

Abstract: Histamine may be quantitatively measured by performing the following steps. First, an oocyte that expresses histamine receptors is held in a recess formed at the bottom of a vessel. Then, first and second electrodes are inserted into the oocyte. Subsequently, the membrane potential of the oocyte is measured by using the first electrode to stabilize this membrane potential at a predetermined level by driving a current through the second electrode using circuitry for clamping the membrane potential of the oocyte. A sample is then infused into a fine reacting tube having an antigen immobilized on its inner surface together with some buffer solution to promote a histamine releasing reaction. The solution containing histamines that is released in the fine reacting tube is transferred to the vessel to make contact with the oocyte in the vessel.

Abstract: Histamine may be quantitatively measured by performing the following steps. First, an oocyte that expresses histamine receptors is held in a recess formed at the bottom of a vessel. Then, first and second electrodes are inserted into the oocyte. Subsequently, the membrane potential of the oocyte is measured by using the first electrode to stabilize this membrane potential at a predetermined level by driving a current through the second electrode using circuitry for clamping the membrane potential of the oocyte. A sample is then infused into a fine reacting tube having an antigen immobilized on its inner surface together with some buffer solution to promote a histamine releasing reaction. The solution containing histamines that is released in the fine reacting tube is transferred to the vessel to make contact with the oocyte in the vessel.

Abstract: A method for determining the mechanical installation parameters of an oxygen sensor so that it will operate within a predetermined temperature range under all operating conditions of the vehicle by setting the desired exposed area of the sensor element tip (S), taking into account: the recommended maximum operational temperature of the oxygen sensor (Ts); the hottest expected temperature of the exhaust gas (Tg); the effective heat transfer rate from the exhaust gas to the sensor element tip, and ultimately to the surroundings, ie., the exhaust pipe sidewall which is in contact with the surrounding ambient air (Q/t); the thermal conductivity of the oxygen sensor (k); and an effective thickness, which depends on where the temperature is measured in the oxygen sensor (x), according to a relation: S=(Q*x)/((Tg−Ts)(t*c*k)). The exposed surface area is then mechanically set, which may include use of a collar concentrically placed around the sensor element tip.

Abstract: A sensor element for an electrochemical sensor, in particular for determining the oxygen content in exhaust gases of an internal combustion engine. The sensor element has at least one measuring electrode exposed to a measuring gas, at least one reference electrode exposed to a reference gas, at least one heating device having one heating conductor and two heating conductor leads, and a reference gas channel. The heating conductor has at least two heating circuit trace segments outside the vertical projection of the reference gas channel, the two heating circuit trace segments being connected by a connecting segment routed over the reference gas channel. The circuit trace cross section of the connecting segment is larger than the cross section of one of the heating circuit trace segments.

Abstract: The present invention provides an apparatus which divides ions present in a liquid in a small amount into positive ions, negative ions, and charge density, measures the divided ions and the charge density, and displays amounts thereof. The apparatus further includes a storing function of data thereof. The apparatus has a signal detecting section 21 having a sensor section 5 disposed in an upper portion of a body 1, a signal detecting box A disposed in a lower portion of the body 1, and including therein a hoisting and lowering bench which moves a container C in which liquids to be measured are held to and from the sensor section 5, and a measuring body B for processing a signal output from the signal detecting section 21, detecting and displaying in accordance with an amount of ions, and for outputting impressed voltage to recording function of data and the sensor section.

Abstract: The invention is directed to a diagnostic arrangement for a potentiometric, electrical exhaust-gas probe for the control of combustion processes with a periodic change of the composition of the combusting air/fuel mixture between oxygen deficiency and oxygen excess. The exhaust-gas probe is heated by an electric heater and outputs a probe signal when the exhaust-gas probe operates without fault which changes between a first region of high signal values (oxygen deficiency) and a second region of low signal values (oxygen excess) with the first region and the second region being separated by a third region of values. A fault announcement is outputted when the probe signal lies within the third region longer than a pregiven longest duration. A fault announcement is also outputted when changes of the current supplied to the electric heater occur within the pregiven longest duration and when the probe signal has temporarily left the third region of values after the change of the heater current.