Abstract: A control device for an exhaust gas sensor includes first means for estimating a temperature of a sensor element in accordance with impedance of a solid electrolyte, and second means for estimating the temperature of the sensor element in accordance with resistance of a heater. A first element temperature according to impedance of the sensor element in a predetermined detection timing is detected by the first means, and a second element temperature according to resistance of a heater of the sensor element in the predetermined detection timing is detected by the second means. The control device corrects the temperature of the sensor element that is estimated in accordance with heater resistance by the second means in accordance with a difference between the first element temperature and the second element temperature.

Abstract: A lambda sensor element includes a substrate made of an insulating ceramic having a bottomed cylindrical shape, an electrolyte part made of a solid electrolyte, and a pair of electrode portions. The electrolyte part is embedded in at least a portion of the side wall of the substrate. The lambda sensor element is used by inserting a rod-like heater in the substrate having the bottomed cylindrical shape. The substrate is formed of the insulating ceramic at a contact position to the heater within the substrate. In a manufacturing of the substrate, a molded body having a space for a forming position of the electrolyte part is formed by using substrate-forming clay, and then the molded body is molded by filling electrolyte-forming clay into the space.

Abstract: An electrochemical oxygen sensor includes a micro-porous plastic membrane supported on a sealing disk and located between a gas inflow port and the sensor's electrolyte. The membrane and disk minimize thermal shock effects due to using the sensor at a first location, at a first temperature, and then moving it to a second location at a different temperature.

Abstract: A microelectrochemical sensor having a diaphragm, a web, a first and a second electrode. The diaphragm is permeable to ions of a chemical species, is arranged transversely with respect to a cutout in a base body, and closes off the cutout in a fluid-tight fashion. The web is arranged on a first side of the diaphragm between a first partial surface and a second partial surface, and is designed to adjust a temperature of the diaphragm to an operating temperature using electrical energy. The first electrode has a first partial electrode and a second partial electrode, is permeable to fluid, and is arranged on the first side of the diaphragm. The web prevents electrical contact between the first electrode and the diaphragm. The second electrode has a third partial electrode and a fourth partial electrode, is also permeable to fluid, and is arranged on a second side of the diaphragm.

Abstract: The invention relates to a method of determining a charged particle concentration in an analyte (100), the method comprising steps of: i) determining at least two measurement points of a surface-potential versus interface-temperature curve (c1, c2, c3, c4), wherein the interface temperature is obtained from a temperature difference between a first interface between a first ion-sensitive dielectric (Fsd) and the analyte (100) and a second interface between a second ion-sensitive dielectric (Ssd) and the analyte (100), and wherein the surface-potential is obtained from a potential difference between a first electrode (Fe) and a second electrode (Se) onto which said first ion-sensitive dielectric (Fsd) and said second ion-sensitive dielectric (Ssd) are respectively provided, And ii) calculating the charged particle concentration from locations of the at least two measurement points of said curve (c1, c2, c3, c4).

Abstract: A gas sensor according to the present invention includes a sensor element made of a solid electrolyte and having at least a cylindrical portion arranged coaxially with an axis of the sensor element and a front end portion closing a front end of the cylindrical portion and a heater formed into either a cylindrical shape or a cylindrical column shape and located inside the sensor element to heat the sensor element by heat generation thereof, wherein a front end portion of the heater is in contact with an inner surface of the front end portion of the sensor element; and wherein a lateral portion of the heater is in contact with an inner circumferential surface of the cylindrical portion of the sensor element.

Abstract: The present invention relates to a cartridge for conducting diagnostic assays. The cartridge consists of an assembly of components that are easily assembled. The cartridge provides means for receiving a patient sample, precisely controlling fluid introduction, onboard storage of assay fluid and conducting different assay protocols and detection of a plurality of analytes. Methods of use for the cartridge are described. The disclosed invention is suitable for point of care environments or any place where rapid, ultrasensitive testing is required.

Abstract: Gas sensors are provided. The gas sensors include a gas sensing element having metal oxide nanoparticles and a thin-film heating element. Systems that include the gas sensors, as well as methods of using the gas sensors, are also provided. Embodiments of the present disclosure find use in a variety of different applications, including detecting whether an analyte is present in a gaseous sample.

Abstract: A control apparatus (100) for a gas sensor (10) which includes a cell (2) composed of a solid electrolyte body and a pair of electrodes provided thereon. The control apparatus includes voltage application means (70) for applying a single pulse voltage to the cell over a constant energization time T; first-output-value obtaining means 70 for obtaining a first output value Vri1 from the cell when a first time t1 shorter than the constant energization time has elapsed; second-output-value obtaining means (70) for obtaining a second output value Vri2 from the cell when a second time t2 shorter than the constant energization time but longer than the first time has elapsed; and deterioration-degree detection means 70 for detecting the degree of deterioration of the cell on the basis of a difference ?Vri between the second output value and the first output value.

Abstract: Disclosed herein are embodiments of an apparatus for analysis of electrochemical dissolution. One embodiment comprises a working electrode submerged in a first reaction chamber containing liquid electrolyte, a counter electrode submerged in a second reaction chamber containing liquid electrolyte, a reference electrode submerged in a third reaction chamber and electrolytically connected to the working electrode and an ion conductor electrolytically connecting the first reaction chamber and the second reaction chamber while physically separating the first reaction chamber and the second reaction chamber.

Abstract: A patch clamp system providing precise and rapid temperature control of constrained cell membranes employs the thermal element attached to the substrate of the patch clamp. In one embodiment, the thermal element is a Peltier device fabricated on a silicon membrane wafer bonded to the substrate of the patch clamp.

Abstract: A gas sensor comprises a layered structure with an ionic conductive film and a high gas-permeability interlayer film, a first catalyst electrode and a second catalyst electrode, a conductivity promotion structure, a high-k layer and a current detecting unit. The ionic conductive film includes a material with ionic conductivity ranging from 0.02 to 1000 S/cm. The first catalyst electrode and second catalyst electrode are located on the layered structure and spaced by a predetermined distance for ionizing gas and converting the ionized gas into gas. The conductivity promotion structure includes a material with electronic conductivity ranging from 10?5 to 105 S/cm, and provides wanted electrons for reaction with the gas. The high-k layer is interposed between the conductivity promotion structure and layered structure. The current detecting unit is coupled the first catalyst electrode and second catalyst electrode to sense a detecting current with respect to the ionized gas.

Abstract: A device for measuring oxidation-reduction potential at operating temperature and pressure in hot water systems is disclosed and claimed. The device includes a flow-through cell, an oxidation-reduction potential probe, a temperature detector, and an external pressure-balanced reference electrode assembly. Each component of the device works in conjunction with the other components and each has electrical connections that transmit signals to a controller. The controller calculates and determines adjustments to feedwater chemistry for the hot water system.

Abstract: A device for measuring oxidation-reduction potential at operating temperature and pressure in hot water systems is disclosed and claimed. The device includes a flow-through cell, an oxidation-reduction potential probe, a temperature detector, and an external pressure-balanced reference electrode assembly. Each component of the device works in conjunction with the other components and each has electrical connections that transmit signals to a controller. The controller calculates and determines adjustments to feedwater chemistry for the hot water system.

Abstract: A gas sensor control apparatus includes a heater regulating section to control the supply of electricity to a heater included in a gas sensor, an impedance sensing section to sense an impedance of the gas sensor cell, an impedance condition examining section to examine whether the impedance is greater than or equal to an abnormality threshold, a voltage condition examining section to examine whether a maximum effective voltage is applied to the heater, when the impedance is above the abnormality threshold, a duration measuring section to examine whether an application time duration of the maximum effective voltage becomes equal to or longer than a heater overheat preventing time, and a voltage decreasing section to decrease the heater voltage to such a lower effective voltage as to hold the temperature of the cell higher than or equal to 500° C. when the application time duration reaches the heater overheat preventing time.

Abstract: A sensor apparatus includes a first electrode and a second electrode at a predefined distance from one another. The sensor apparatus includes a substrate arranged in a predefined first region of the sensor carrier such that the first electrode and the second electrode are substantially electrically decoupled from one another if the outer side of the sensor carrier is substantially free of particles. A third electrode is coupled to a solid electrolyte that is additionally coupled to the second electrode. A diffusion barrier is coupled to the third electrode in a predefined third region and the exhaust gas is applied to the third electrode only in the third region via the diffusion barrier.

Abstract: An analytical device including a sensor, an analytical circuit, and a power source. The power source includes an optical coupler formed of a light source and a photovoltaic cell for producing an electromotive force in response to light from the light source. The optical coupler is configured to provide the electromotive force to the analytical circuit. The power source may be configured for separation between the power supply and the resulting electromotive force supplied to the analytical circuit. Various aspects of the invention are directed to providing a power source for one or more components of an electrochemical detector. A method of providing power to an analytical instrument is also disclosed.

Abstract: A test sensor includes a body, a first conductive trace, a second conductive trace, and a third conductive trace. The body includes a first region that has a fluid-receiving area, a second region separate from the first region, and a first temperature sensing interface disposed at or adjacent to the fluid-receiving area. The fluid-receiving area receives a sample. The first trace is disposed on the body, and at least a portion of the first trace is disposed in the first region. The second and third traces are disposed on the body. The third trace extends from the first to the second regions. The third trace is connected to the first trace at the first temperature sensing interface. The third trace includes a different material than the first trace. A first thermocouple is formed at the first temperature sensing interface. The thermocouple provides temperature data to determine an analyte concentration.

Abstract: The present the invention provides methods, devices and systems for rapidly measuring analytes within a biological sample.

Abstract: The invention relates to a pH measuring device containing a reference cell which includes a tank filled with an electrolyte solution and a platinized platinum reference electrode immersed in the tank. The measuring device also contains a measuring cell. The measuring cell contains a platinized platinum measuring electrode which is immersed in the solution to be measured. The measuring device also contains a temperature regulator to ensure that the temperature is the same in the reference cell as in the measuring cell. The measuring device also contains a particle pressure regulator to ensure that the hydrogen partial pressure is the same in the reference cell as in the measuring cell and a fluid pressure regulator to ensure that the pressure is the same in the reference cell as in the measuring cell.

Abstract: A gas sensor element with a bottom part is composed of at least a solid electrolyte body of oxygen ion conductivity, a reference electrode, a detection electrode, an electrode protection layer which supports noble metal catalyst, and a heater. The electrode protection layer is composed of a covering layer, a catalyst layer and a poisoning layer. A quantity of the noble metal catalyst supported in the electrode protection layer at the bottom part of the gas sensor element is larger than that in the electrode protection layer at a leg part of the gas sensor. The bottom part of the gas sensor element has a high temperature rising speed more than the leg part when the heater generates heat energy.

Abstract: The present invention relates to diagnostic devices incorporating electrode modules and fluidics for performing chemical analyses. The invented devices consist of at least one component sensor formed on an electrode module, the sensor being contained within a fluidic housing. The electrode module is a laminate of a perforated epoxy foil and a photo-formed metal foil with sensor membranes deposited into the perforations. The fluidic housing is a diagnostic card consisting of a plastic card-like body, the at least one component sensor, a sealed chamber defined in the card body for containing a fluid, a fluid conduit for fluidically connecting the chamber with the sensor region, a valve for fluidically connecting the chamber to the fluid conduit, and a delivery structure separate and distinct from the valve for forcing fluid from the chamber and into the fluid conduit.

Abstract: A gas sensor element having a chamfered portion. The chamfered portion has a leading end chamfered portion formed in a leading end portion of the gas sensor element, a rear end chamfered portion formed in a rear end portion of the gas sensor element, and an intermediate chamfered portion linking the leading end chamfered portion and rear end chamfered portion. The chamfer angle of the rear end chamfered portion is formed so as to be larger than the chamfer angle of the leading end chamfered portion.

Abstract: An amperometric electrochemical sensor configured to be operable in an oxidizing atmosphere and under an applied bias to exhibit enhanced reduction of oxygen molecules at the sensing electrode in the presence of one or more target gas species and a resulting measurable increase in oxygen ion flux through the cell. The sensor has an electrolyte membrane, a sensing electrode on the electrolyte membrane, and a counter electrode on the electrolyte membrane, wherein the sensing electrode includes at least one molybdate or tungstate compound. An electrochemical sensor system is also provided, along with a method of detecting the concentration of one or more of NOx and NH3 in a gas sample or stream.

Abstract: An amperometric probe suitable for monitoring chlorine levels in water is described. The probe has low power consumption and maintenance requirements rendering it particularly suitable for long periods of operation in remote locations with portable power supplies.

Abstract: The invention comprises portable, rugged and relatively compact electrochemical cells. Each may be removably and nondestructively secured to one surface of a substrate of indefinite size. In-situ electrochemical measurements may be made on portions of existing structures such as ships, bridges, or buildings. An electrochemical cell is disclosed which comprises an analytical chamber which can be utilized with either on-board or external potentiostats. The electrochemical cell has a mounting means which permits the cell to be secured to substrates with irregular surface morphology and to horizontal, vertical or intermediately oriented surfaces. The electrochemical cell provides a means to control the temperature of the electrolyte and the substrate area of interest to permit more accuract and consistent elecrochemical measurements.

Abstract: A method for detecting nitrogen oxides, the method comprising monitoring the change in potential difference between a working electrode and a reference electrode as the working electrode is exposed to nitrogen oxides, where the working electrode includes an inorganic non-metallic oxide selected from spinel-structured compounds and wolframite-structured compounds, and where the working electrode and the reference electrode are in contact with a solid electrolyte.

Abstract: When a detection signal obtained from the cell of a gas sensor (S15) has reached a start determination value (specifically, when the output voltage of the cell is higher than 600 mV (S16: YES) or lower than 300 mV (S17: YES)), a pulse voltage is applied to the cell (S18), and a start-time internal resistance is obtained on the basis of the detection signal having changed as a result of application of the pulse voltage (S20). The start-time internal resistance is compared with a deterioration determination value set in advance (S21). A target resistance of the cell used in temperature control (energization control) for the heater is corrected in accordance with the result of the comparison (S28). Thus, the temperature of the cell can be stably maintained constant irrespective of deterioration of the cell.

Abstract: A method of measuring a quantity of a substrate contained in sample liquid is provided. This method can reduce measurement errors caused by a biosensor. The biosensor includes at least a pair of electrodes on an insulating board and is inserted into a measuring device which includes a supporting section for supporting detachably the biosensor, plural connecting terminals to be coupled to the respective electrodes, and a driving power supply which applies a voltage to the respective electrodes via the connecting terminals. One of the electrodes of the biosensor is connected to the first and second connecting terminals of the measuring device only when the biosensor is inserted into the measuring device in a given direction, and has a structure such that the electrode becomes conductive between the first and second connecting terminals due to a voltage application by the driving power supply.

Abstract: A gas sensor is provided with a multilayer body of solid electrolyte layers, a measurement electrode, a reference electrode, a reference gas introduction layer, a detection unit and a heater. The reference electrode and the measurement electrode are formed directly on the same first solid electrolyte layer. Thus, heat from the heater is transferred from a third substrate layer to the first solid electrolyte layer, and also to the reference electrode and the measurement electrode through the same first solid electrolyte layer. The reference electrode is covered with a reference gas introduction layer, formed of a porous body. The transference of heat from the heater to the reference electrode through the reference gas introduction layer is smaller than the transference of heat from the heater to the reference electrode through the first solid electrolyte layer on which the reference electrode is formed directly.

Abstract: Improvements in references electrodes, halogen sensors, pH sensors, TDS sensors, combinations thereof, and related methods.

Abstract: A gas sensor element has a first cell, a second cell, and a solid electrolyte layer having proton conductivity commonly used by the first cell and the second cell. The first cell has a first cathode and a first anode exposed to the target detection gas containing hydrogen atoms. The second cell has a second anode, a second cathode, and a shield layer with which the second anode is covered. A voltage is supplied to the first and second cells. A gas concentration of the target detection gas is calculated on the basis of a difference between a current of the first cell and a current of the second cell because the current in the first cell is a sum of proton conductivity current and an electron conductivity current. The current in the second cell is an electron conductive current only.

Abstract: A temperature of a gas sensor may be adjusted to a first temperature value for a first period of time and a second temperature value for a second period of time. A signal of the gas sensor may be measured during the first period of time to determine a first signal value and during the second period of time to determine a second value. Then, concentration information for at least one gas is calculated according to the first signal value and the second signal value. While the gas sensor signal may include information about a presence of a first gas and a second gas, the concentration information for the at least one gas may not substantially include concentration information for the second gas.

Abstract: An electrochemical oxygen sensor includes a micro-porous plastic membrane supported on a sealing disk and located between a gas inflow port and the sensor's electrolyte. The membrane and disk minimize thermal shock effects due to using the sensor at a first location, at a first temperature, and then moving it to a second location at a different temperature.

Abstract: A porous structure including a pair of electrodes disposed in a flow direction of exhaust gas and a solid electrolyte interposed between the electrodes is arranged in an exhaust passage of an internal combustion engine, and the amount of a particulate matter in exhaust gas is specified based on a potential difference generated between the electrodes.

Abstract: The invention relates to a method for the voltage-controlled performance regulation of the heating of an exhaust-gas probe in the exhaust system of an internal combustion engine. The aim of the invention is to provide a method in which the operating temperature of the probe is achieved in the shortest possible time without damage to the probe. To achieve this, the heating voltage during the heating phase of the probe is rapidly brought up to a high temperature in a start phase in relation to a subsequent phase, or a dramatic leap in temperature is achieved, preferably up to the full operating voltage and the heating voltage is then continuously or quasi-continuously reduced.

Abstract: A system and method for online monitoring of molten salt corrosion of a component of an apparatus is disclosed. First and second electrodes are electrically isolated from each other within the component and exposed to a corrosive operating environment of the apparatus. The first and second electrodes are electrically coupled such that when an electrical potential difference exists between the first and second electrodes an electrical current flows between the first electrode and the second electrode. The electrical potential difference between the first electrode and the second electrode is based at least in part on molten salt corrosion at the first electrode or the second electrode. At least one of the electrical potential difference or the electrical current flowing between the first electrode and second electrode is measured and analyzed such that a corrosion characteristic of the component can be predicted.

Abstract: A control apparatus (100) for a gas sensor (10) which includes a cell (2) composed of a solid electrolyte body and a pair of electrodes provided thereon. The control apparatus includes voltage application means (70) for applying a single pulse voltage to the cell over a constant energization time T; first-output-value obtaining means 70 for obtaining a first output value Vri1 from the cell when a first time t1 shorter than the constant energization time has elapsed; second-output-value obtaining means (70) for obtaining a second output value Vri2 from the cell when a second time t2 shorter than the constant energization time but longer than the first time has elapsed; and deterioration-degree detection means 70 for detecting the degree of deterioration of the cell on the basis of a difference ?Vri between the second output value and the first output value.

Abstract: A degradation detector of an exhaust gas sensor is disclosed. The detector comprises a first heater resistance estimator (16) for estimating a resistance of a heater that heats the exhaust gas sensor, based on a device resistance of the exhaust gas sensor; a heater resistance calculator (17) for calculating a resistance of the heater, based on a heater current of the heater; and a degradation determiner (18) for determining whether the exhaust gas sensor is degraded, by comparing the estimated resistance of the heater and the calculated resistance of the heater.

Abstract: A hydrogen gas sensor comprising a detection electrode, a reference electrode, and an electrolyte contacting with these electrodes, in which the reference electrode and the detection electrode are composed of a material having a property that hydrogen molecule doesn't voluntarily dissociate into atomic hydrogen on a surface of the electrode in Standard State such as nickel, titanium, copper, tungsten and the like, in which hydrogen gas is detected by an electromotive force generated between the reference electrode and the detection electrode while at least the detection electrode is maintained at a temperature not less than a temperature that hydrogen molecule begins to dissociate into atomic hydrogen voluntarily on the surface of the detection electrode.

Abstract: The invention relates to a measuring device (1) for measuring the pH of a solution to be measured comprising: a reference cell (2) including: a tank (20) filled with an electrolyte solution; a platinized platinum reference electrode (21) immersed in the tank (20); a measuring cell (4) including: a platinized platinum measuring electrode (41) to be immersed in the solution being measured; wherein the measuring device (1) also comprises: a temperature regulator (RT) to ensure the same temperature in the reference cell (2) and the measuring cell (4); a partial pressure regulator (RPP) to ensure the same hydrogen partial pressure in the reference cell (2) and the measuring cell (4).

Abstract: Electrochemical devices, methods, and systems for detecting and quantifying analytes are disclosed. A chemical detection reagent is locally generated in a test solution by electrochemical reaction of a precursor compound caused to migrate into the test solution from a precursor solution separated from the test solution by a cell separator. This approach provides precise metering of the reagent, via the charge passed, and avoids the need to store a reagent solution that may be chemically unstable. In one embodiment, the starch concentration in a colloidal solution can be measured via spectroscopic detection of a blue complex formed by the interaction of starch with iodine produced, on demand, by electrochemical oxidation of iodide ion. The approach may also be used to characterize certain types of analytes. The invention is amenable to automation and is particularly useful for on-line monitoring of production processes, including the inclusion of feed back loop mechanisms for process control.

Abstract: There is provided a sample preparation device and method for preparing a sample of liquid for detection of impurities. First (40) and second (38) electrodes are provided, located for immersion in a liquid under test. A semipermeable membrane (42) is positioned to protect the first electrode (40) from a body of liquid under test (32). The semipermeable membrane allows the liquid under test to pass therethrough to reach the first electrode, while preventing solids carried in the liquid from reaching the first electrode, the first electrode being positioned to affect the liquid under test in the vicinity of a sensor (36). Particular embodiments feature a hydrophilic membrane to protect the electrodes from suspended solids in the sample, a thin electrode assembly to achieve a faster response and the addition of a heater for temperature control to achieve consistent detection conditions and improved anti-fouling properties.

Abstract: An apparatus for detecting chemical reactions may be provided. The apparatus may comprise a chemical detection device. The chemical detection device may include a chemical sensor, which may be mounted on the chemical detection device. The apparatus may further comprise a valve block. The valve block may fluidly couple a plurality of reagent containers to the chemical detection device. The apparatus may further comprise a heat exchanger and a controller. The controller may control a fluid connection between the valve block and the chemical detection device. The controller may be also configured to adjust a temperature of a selected reagent from the plurality of reagent containers via the heat exchanger. The temperature of the selected reagent may be adjusted prior to the reagent entering the chemical detection device.

Abstract: The invention relates to an electrochemical sensor and method for providing the sensor having an insulator, an electrode deposited on the insulator, an electrolytic material in contact with the electrode for providing an electrical connection, and a cooling and heating element in contact with the insulator and spaced apart from the electrode for adjusting a temperature of the sensor.

Abstract: An electrochemical sensor is described, containing a sensor substrate and at least one set of electrodes comprising a working electrode, a reference electrode and optionally an auxiliary electrode, further containing at least one reaction vessel, which is tightly connected to the sensor substrate and inside which is located at least one working electrode, whereas at least a part of the sensor substrate forms a vessel bottom. The vessel can contain a lid and also other preferred embodiments are described. The invention further describes a method of manufacture of the electrochemical sensor with the integrated reaction vessel, particularly by injection moulding.

Abstract: A gas sensor element with a bottom part is composed of at least a solid electrolyte body of oxygen ion conductivity, a reference electrode, a detection electrode, an electrode protection layer which supports noble metal catalyst, and a heater. The electrode protection layer is composed of a covering layer, a catalyst layer and a poisoning layer. A quantity of the noble metal catalyst supported in the electrode protection layer at the bottom part of the gas sensor element is larger than that in the electrode protection layer at a leg part of the gas sensor. The bottom part of the gas sensor element has a high temperature rising speed more than the leg part when the heater generates heat energy.

Abstract: A sensor element is provided for determining at least one physical property of a gas mixture in at least one gas chamber, which includes at least one component to be identified, especially oxygen, and at least one oxidizable component, especially a combustion gas. The sensor element has at least one first electrode, at least one second electrode, and at least one solid electrolyte connecting the at least one first electrode and the at least one second electrode. The at least one second electrode has a lower catalytic activity, particularly a lower electrocatalytic activity with respect to the at least one oxidizable component than the at least one first electrode.

Abstract: Temperature compensation for ion-selective electrodes is obtained by positioning a temperature-measuring element in a chamber of limited thermal mass which is in thermal contact with the measuring electrode filling solution but is thermally isolated from other filling solutions in the electrode. In a preferred embodiment, the temperature-measuring element comprises a thermistor enclosed within thin flexible tubing; the electrical leads of the thermistor are forced against a segment of the inner wall of the tubing by an elongated strand of material abutting the thermistor to enhance heat transfer with the thermistor.

Abstract: The concentration of the urea of a urea solution is identified accurately and immediately. A pulse voltage is applied for a predetermined time to a urea concentration identifying sensor heater including a heater and an identifying liquid temperature sensor provided in the vicinity of the heater, a urea solution to be identified is heated by the heater, and the concentration of the urea is identified with a voltage output difference V0 corresponding to a temperature difference between an initial temperature and a peak temperature in the identifying liquid temperature sensor.