Abstract: Crystalline colloidal arrays (CCA) which have been encapsulated in a polymer matrix to produce more robust polymerized crystalline colloidal arrays (PCCA) are provided. The PCCA's of the present invention can be in the form of a hydrogel which can be compatible for use with a biological system. The polymer matrix of the PCCA is formed of polymerized poly(ethylene glycol) based monomer units which can provide a desired functionality to the PCCA. The PCCA can be formed to exhibit a photonic bandgap at a certain wavelength. The photonic bandgap can be capable of shifting upon some form of environmental stimulation rendering the PCCA suitable for many optical applications, including active photonic switching and sensory applications.

Abstract: A diagnostic system for monitoring catalyst performance in an exhaust system comprises a plurality of treatment devices catalytically treating an exhaust gas stream, and a plurality of gas sensors for monitoring the catalyst performance of the treatment devices to determine when sulfur poisoning occurs. An on-board diagnostic system receives signals from the gas sensors, and, based upon response time differentials between sensors, determines whether the treatment devices are experiencing sulfur poisoning.

Abstract: The present invention provides a NOx-concentration measuring apparatus D for quantitatively analyzing the concentration of NOx contained in a sample gas. The measuring apparatus D comprises a sampling probe for obtaining the sample gas, a drain separator 2 for condensing moisture contained in the sample gas as a condensed water and separating the condensed water from the sample gas, an NO2 converter 3 for converting NO2 contained in the sample gas into NO, a secondary cooling device 7 for additionally cooling the sample gas, and an NO analyzer 1, arranged in this order with respect to a sample-gas line of the NOx-concentration measuring apparatus. The drain separator is a high-flow-velocity cooling type drain separator. Further, the sample-gas line between the sampling probe and the drain separator is heated and/or thermally insulated over the entire length thereof. The measuring apparatus can provide a high-precision measurement while suppressing NO2 loss.

Abstract: Methods and apparatus are described for preventing nitrogen interference in the detection of a substance. In particular, it relates to new methods and apparatus for preventing interference due to nitrogen in pyro-electrochemical methods for measuring substances, for example sulfur content, contained within liquids such as petroleum products and beverages. One preferred apparatus and method comprises a catalytic converter or thermal converter to selectively remove the nitrogen-containing interferant, for example NO2, in the pyrolyzed gas stream to NO without affecting the sulfur content. A second preferred apparatus and method comprises a chemical scrubber to selectively remove the nitrogen-containing interferant from the gas stream without affecting the sulfur content.

Abstract: A detection system for detecting contaminant gases includes a converter, a detector, a primary channel for delivering a target gas sample through the converter to the detector, and at least two scrubbing channels for delivering a reference gas sample through the converter to the detector. Each of the scrubbing channels includes a scrubber for removing basic nitrogen compounds from the reference gas sample, while the primary channel preferably transmits the target gas sample without scrubbing. The converter converts gaseous nitrogen compounds in the target gas sample to an indicator gas, such as nitric oxide (NO), and a control system directs the flow of a gas sample among the primary channel and the scrubbing channels. In accordance with one aspect of the invention, the basic-nitrogen-compound concentration can be measured by comparing the concentration of the indicator gas detected in the reference sample with the detected indicator-gas concentration in the target sample.

Abstract: An analytical system is provided for determining nitrogen monoxide, nitrogen dioxide and ozone concentrations in air samples. An ultraviolet light source 4 is used to alter the equilibrium between nitrogen dioxide and oxygen on the one hand and nitrogen monoxide and ozone on the other. Dynamic measurement of ozone concentration with time whilst ultraviolet irradiation is pulsed enables each gas concentration to be calculated without requiring input gases to be scrubbed. An aApparatus 101 is further provided to provide a controlled flow of gas to a sensor 103 attached to a high altitude balloon whilst sheltering it from the elements and allowing for affects of temperature, said apparatus comprising a shield 104 and a gas conducting means which uses the venturi effect to control air flow or has a hole to allow water to drain without affecting air flow past the sensor.

Abstract: In order to prevent a catalyst for an internal combustion engine from decreasing efficiency by deterioration after long time use of the catalyst, the decreased efficiency of the catalyst is determined, and the internal engine is controlled based on results of the determination so as to maintain high efficiency of the catalyst. The catalyst is installed in an exhaust pipe of the engine. Sensors for detecting conditions of exhaust gas both at upstream side and downstream side of the catalyst are provided, respectively. As for the sensor, for example, an oxygen sensor of which output varies stepwise at &lgr;=1, or a sensor of which output varies in proportion to air-fuel ratio can be used. Detected values of the sensors are taken into a control unit, eliminating efficiency and deteriorating degree of the catalyst are estimated by comparison of the detected values, and the engine is controlled so that the eliminating efficiency becomes maximum.

Abstract: Many of the effects of nitric oxide are mediated by the direct modification of cysteine residues resulting in an adduct called a nitrosothiol. A method to detect proteins which contain nitrosothiols involves several steps. Nitrosylated cysteines are converted to tagged cysteines. Tagged proteins can then be detected, for example, by immunoblotting and/or can be purified by affinity chromatography. The method is applicable to the detection of S-nitrosylated proteins in cell lysates following in vitro S-nitrosylation, as well as to the detection of endogenous S-nitrosothiols in selected protein substrates.

Abstract: A diagnostic system for monitoring catalyst performance in an exhaust system comprises a plurality of treatment devices catalytically treating an exhaust gas stream, and a plurality of gas sensors for monitoring the catalyst performance of the treatment devices to determine when sulfur poisoning occurs. An on-board diagnostic system receives signals from the gas sensors, and, based upon response time differentials between sensors, determines whether the treatment devices are experiencing sulfur poisoning.

Abstract: A method and apparatus for measuring the concentration of at least one gaseous component and/or vaporous component of a gaseous mixture in which a controlled sensor flame is introduced into the gaseous mixture and at least one narrow spectral band in the controlled sensor flame is optically measured. The concentration of the gaseous component using a result obtained from the optical measuring of the at least one narrow spectral band is then calculated. The method of this invention is particularly suitable for substantially real-time control of combustion processes.

Abstract: A compound of the formula wherein X is Cl or CH3, or a salt thereof, is useful as a spin trap in various assays.

Abstract: System for detection and analysis of gas samples in fieldable real-time Differential Mobility Spectrometry (DMS) chemical sensor system which uses non-radioactive ion source for monitoring and detecting NOx emissions; provides reliable methods for detecting and monitoring of anthropogenic sources of NOx; also detection of NO in exhaled breath for patient health diagnosis.

Abstract: A compound represented by the following formula (I) or (II): wherein, in the formula (I), R1, R2, R3, and R4 independently represent methyl group or ethyl group; and in the formula (II), R5, R6, R7, and R8 independently represent methyl group or ethyl group and X− represents an anion, and a reagent for measurement of nitric oxide which comprises said compound.

Abstract: A semiconductor device (FIG. 1) is provided for the detection of nitric oxide (NO) molecules in gaseous mixtures, in biological fluids and in aqueous solutions. The device is a molecular controlled semiconductor resistor (MOCSER) of a multilayered GaAs structure to which top layer a layer of multifunctional NO-binding molecules are adsorbed. The sensitivity of the semiconductor device towards NO is independent of mixture composition. Nitric oxide concentrations of as low as 10 ppb NO were detected in mixtures containing various contaminants.

Abstract: This invention relates a chemiluminescent gas analyzer for determining a concentration of a gaseous component (G1) in a sample gas mixture (2). The analyzer comprises a measuring chamber (3), an ozonizer (4) with ozone generating devices (44) for producing ozone-containing gas (G2), input conduits (24, 23) for delivering the ozone-containing gas and said gas mixture into the chamber and an outlet (18). A detector (7) receives radiation (E) emitted as a consequence of a reaction between the gaseous component and the ozone-containing gas. Said analyzer further comprises a flow delay device (41) in or upstream the input conduit for said ozone-containing gas and downstream from the ozone generating devices (44) of the ozonizer. The flow delay device has a delay volume (VD) causing a predetermined delay time (T) for the flow of the ozone-containing gas from said ozonizer to said measuring chamber (3).

Abstract: The present invention relates to an apparatus and method for determining the concentration of nitric oxide (NO) in a gas mixture such as air. The gas sample containing NO is mixed with a gas containing ozone (O3), and the change in the ozone concentration is measured after a sufficient time is allowed for the reaction between NO and O3 to take place and destroy a measurable quantity of O3. In the preferred embodiment, the concentration of ozone is measured using the technique of UV absorption. In this case, the invention has the advantage over other instruments for measuring NO of having absolute calibration based on the known extinction coefficient for ozone at ultraviolet wavelengths. The invention discloses both static and dynamic flow systems, and the NO concentration measurements may be made over a wide pressure range.

Abstract: The mixed oxide WxMo1-xO3, where preferably x can be in the range 0.01 to 0.9, is very useful for the detection of oxidizing gases and in particular is superior for the detection of ozone. The preferred composition is in the range of 1% to 21% Mo (i.e. 99% to 79% W). The present example in which the composition of the sensing material is in the range WxMo1-xO3 with x varying from 0.01 to 0.9, is clearly distinct from the device claimed in applicant's earlier patent. Precipitation of the material as a mixed oxide from an aqueous solution of the ammonium metallates in concentrations of the appropriate stoichiometric proportions yields a powder that can be screen-printed to give an ideal microstructure. Resistivity of the material may be tailored to a desired value by adjusting the Mo/W ratio within the single phase field. Varying this ratio adjusts catalytic properties of the material.

Abstract: An optical sensor for detection of gases such as nitrogen oxides includes a thin film of an active material comprising a highly polarisable organic material deposited by the Langmuir-Blodgett technique or otherwise on a substrate and interrogated optically, to detect changes in at least one optical property such as reflectance or complex refractive index. Preferred materials include a specific polysiloxane and low-molecular-mass compounds (FIGS 1 to 5b), having specific electron donating and/or accepting groups, including azobenzenes. The optical change may include a visible colour change.

Abstract: The concentration of nitric oxide in a gas is determined by oxidizing NO to NO2 and then measuring the concentration of NO2 in the gas, which is proportional to the concentration of NO. Preferably, gaseous NO2 molecules diffuse through a plurality of capillary membrane fibers and undergo a chemiluminescent reaction with a reagent flowing within; the light from the reaction is measured to determine NO2 concentration. In another aspect of a preferred embodiment, gas is passed through a scrubber before the concentration of NO2 is measured, in order to substantially remove carbon dioxide and ambient NO2 from the gas without substantially affecting the concentration of nitric oxide therein.

Abstract: An analyzer compensates for gas flow perturbations by providing a makeup flow of carrier gas to maintain the pressure and/or flow rate of analyte and inert gas through a detector constant such that a accurate determination of a low concentration of an analyte in the presence of a high concentration of a second analyte can be accurately determined. In one embodiment, a carrier gas is introduced through a valve responsive to the detected pressure in the gas flow stream between a scrubber and a subsequent detector for maintaining the pressure constant during an analysis. In another embodiment of the invention, a flow transducer is positioned in the gas flow path between the scrubber and detector and coupled to a flow control valve coupled to introduce carrier gas as a function of detected gas flow such that the flow rate of gas into the detector is maintained constant.

Abstract: A compound represented by the following formula (I): 1

Abstract: Methods and kits are provided for diagnosing medical conditions of patients with a disease or condition characterized by endothelial dysfunction based on a nitric oxide bioactivity index. Nitric oxide bioactivity index is the ratio of the level of a nitric oxide-related product such as nitrate or nitrite to the level of an oxidant stress-related product such as isoprostane in plasma, urine, or another specimen from a patient. Methods are also provided for using the nitric oxide bioactivity index to treat patients with endothelial dysfunction and monitor the course of treatment.

Abstract: A solid phase chemical sensor includes a polymer film which has a chemiluminescent reagent immobilized therein. The polymer film and chemiluminescent reagent are chosen to significantly enhance the selectivity of the sensor to the analyte in the gaseous phase to which the sensor is exposed. The sensor is then positioned so that, when exposed to the gaseous mixture, any chemiluminescence generated will be detected by a photomultiplier tube or other photoelectric device, such as a photodiode. The sensor is particularly useful in the detection of O2, N2H4, SO2, NO2, and halogenated hydrocarbons.

Abstract: An airtight configuration for keeping down the permeation of corrosive gas from silicone adhesive, and for preventing corrosive gas from entering the case.

Abstract: A method and system for determining a concentration level of NOx in an exhaust stream from a combustion source. The method comprises capturing sample gas from the exhaust stream using a sampling device. NO2 in the sample gas is converted to NO by passing the sample gas through a catalytic NO2 converter. The method also comprises removing water from the sample gas by passing the sample gas through a dryer and determining a sample gas NO concentration level. The step of converting NO2 is performed at a temperature above the dew point temperature of the sample gas.

Abstract: A method and system for determining a concentration level of NOx in an exhaust stream from a combustion source. The method comprises capturing sample gas from the exhaust stream using a sampling device. NO2 in the sample gas is converted to NO by passing the sample gas through a catalytic NO2 converter. The method also comprises removing water from the sample gas by passing the sample gas through a dryer and determining a sample gas NO concentration level. The step of converting NO2 is performed at a temperature above the dew point temperature of the sample gas.

Abstract: An improved on-stream analyzer for monitoring sulfur or nitrogen content of liquid petroleum or beverage products is described. It consists of the following main components: a sample injector for injecting predetermined fixed volumes of the liquid into a thermal oxidizer (pyrolyzer) at a preset, controlled rate, a thermal oxidizer in which an inert carrier gas and oxygen are introduced at measured and preset, controlled rates to thermally oxidize the sample at a temperature of about 1050° C., sample conditioner to control the relative humidity and temperature of the resulting gas mixture, an electrochemical cell sensitive to sulfur dioxide (SO2) or NO to measure the concentration of SO2 or NO in the gas mixture, and a programmable logic controller (PLC) to calculate the sulfur content of the original sample and manage the analyzer.

Abstract: The present invention concerns a continuous analyser of volatile organic compounds (10) comprising a circuit (18) for the sequential processing of air such that the air is drawn in by a pump (17) through a filter (11) and scanned by a first sensor (15) for CO/VOC and the second sensor (16) for H2O, either directly along a first pathway, or after passing through a cartridge (12) for retaining organic species along a second pathway; the switch over from one to the other of these two pathways being assured by an electric valve (13) controlled by a sequencer (14).

Abstract: A method and apparatus for measuring the concentration of at least one gaseous component and/or vaporous component of a gaseous mixture in which a controlled sensor flame is introduced into the gaseous mixture and at least one narrow spectral band in the controlled sensor flame is optically measured. The concentration of the gaseous component using a result obtained from the optical measuring of the at least one narrow spectral band is then calculated. The method of this invention is particularly suitable for substantially real-time control of combustion processes.

Abstract: The present invention relates to a modular analyzer system for the analysis of at least two or more chemical components contained in pickle liquor solution. The analyzer modules include a strong acid analysis module, a weak acid analysis module, an oxidizer analysis module, and a metal ion analysis module. These four modules may be used in any combination, including the use of more than one of the same type of analysis module.

Abstract: The invention concerns a chemiluminescent gas analyzer (1) for determining a concentration of a gaseous component (G1) in a sample gas mixture (2). The analyzer comprises a measuring chamber (3) having a reflective inner surface (27) and a transparent window (22). A substantial height portion of the reflective inner surface is composed of at least one convergent surface section tapering towards a bottom (35) of said chamber. The input conduits (23, 24) have at least one orifice within a bottom end region (45) of said chamber, said bottom end region being within the height portion for said convergent surface section(s). Further, there is an outlet (18) for removing said gases and possible chemical compounds from the chamber. The pressure (P) within the measuring chamber is at least 0.2 bar. A radiation sensitive detector (7) is directed to said window and said chamber for receiving radiation (E) emitted as a consequence of a reaction between the gaseous component and the gaseous reagent.

Abstract: A compound represented by the following formula (I): 1

Abstract: In order to prevent a catalyst for an internal combustion engine from decreasing efficiency by deterioration after long time use of the catalyst, the decreased efficiency of the catalyst is determined, and the internal engine is controlled based on results of the determination so as to maintain high efficiency of the catalyst. The catalyst is installed in an exhaust pipe of the engine. Sensors for detecting conditions of exhaust gas both at upstream side and downstream side of the catalyst are provided, respectively. As for the sensor, for example, an oxygen sensor of which output varies stepwise at &lgr;=1, or a sensor of which output varies in proportion to air-fuel ratio can be used. Detected values of the sensors are taken into a control unit, eliminating efficiency and deteriorating degree of the catalyst are estimated by comparison of the detected values, and the engine is controlled so that the eliminating efficiency becomes maximum.

Abstract: A gas sensor for use in monitoring gases such as H2S, NO2 or SO2 comprises a film or layer of non-protonated polyaniline as the gas sensing material.

Abstract: A gas sensor for sensing NOx having electrochemical cells wherein dielectric material surrounds electrolytes except where electrodes are attached. Thereby, the exhaust gas is effectively prevented from contacting the electrolytes of the sensor's electrochemical cells. With the use of this technique, signal cross talk is minimized while enhancing NOx sensing sensitivity. Further, the total number electrodes needed are reduced which allows for more complex sensors structures.

Abstract: A sensor is disclosed that comprises an electrolyte disposed between and in intimate contact with a sensing electrode and a reference electrode. A protective coating is disposed on the protective layer adjacent to the sensing electrode. The protective coating comprises a mixture of a metal oxide, a zeolite, and an alumina. A method for making the sensor is also disclosed.

Abstract: A film-type vaporizer in a vaporization enclosure, for example the upper column of a double air-distillation column, is associated with a measurement and analysis box where a polished surface and a spillway reconstruct the flow of liquid in the vaporizer in order to check for the absence of the deposition of impurities in the liquid that is to be evaporated. If deposition occurs, the impurities involved are quantified and analyzed and appropriate action taken on the settings of the machine.

Abstract: In accordance with the present invention, there are provided articles for use in non-invasive measurements of nitric oxide levels in a variety of fluid media, e.g., in mammalian body fluids. Articles according to the present invention comprise a nitric oxide trapping agent contained within a vessel, wherein the vessel comprises a semi-permeable membrane. Nitric oxide diffuses through the semi-permeable membrane and is trapped therein for subsequent quantitative analysis. Articles of the present invention are particularly useful in selectively detecting nitric oxide in the presence of other NOx species.

Abstract: Diagnostic methods for determining an instantaneous rate of pollutant formation in a combustion system are based on measurement of chemiluminescence intensity generated simultaneously with the formation of the pollutant. The chemiluminescent signal is generated by an analog reaction which occurs in parallel with a key step in the formation of a specific pollutant of interest. The connection between the analog reaction and the pollution reaction is such that the chemiluminescent signal indicates the local, instantaneous formation rate of the pollutant of interest.

Abstract: A compound represented by the following general formula: 1

Abstract: A method for detecting the onset of chronic rejection at an early stage after organ transplantation, characterized by assaying nitrogen trioxide (NO3), matrix metalloproteinase (MMP)-2 or the precursor thereof in body fluids drawn out of body.

Abstract: A method and apparatus are disclosed for the near simultaneous detection of light emitted from ozone induced chemiluminescence of nitrogen and sulfur species capable of undergoing ozone induced chemiluminescence in a single instrument. A sample containing sulfur and/or nitrogen is first subjected to an oxidative/reductive process which generates ozone reactive nitrogen and sulfur species which are then forwarded to an specially designed ozone/detector chamber. The ozone relative species are brought in contact with ozone in the special chamber and the chemiluminescence of the nitrogen species and the sulfur species are measured and quantitated.

Abstract: A stable sensor designed to detect accurately the total NOx concentration under 100 ppm in terms of the NO gas concentration is made up of a first cell and a second cell with a gas diffusion aperture provided between the two cells. The first cell has a partition wall of a substrate of oxygen ion conductor containing zirconia as the main component and permitting a gas to be detected to enter the zirconia substrate; oxygen pumping electrodes are also formed on the first cell substrate which functions to expel oxygen in an atmosphere of the first cell to the outside and to reduce NO.sub.2 of the NOx gas to be detected to NO gas.

Abstract: A detector for detecting and measuring nitric oxide. Gas-permeable capillary membrane fibers transport a reagent solution through a plenum containing gases to be measured. Nitric oxide molecules penetrate the walls of the fibers and undergo a chemiluminescent reaction within. The fibers and the plenum are translucent, allowing photons emitted by the chemiluminescent reaction to escape and be detected by a photodetector. The reagent is buffered at an alkaline pH and mixed with the enzyme carbonic anhydrase to minimize the measurement errors caused by the presence of carbon dioxide in the gas to be measured.

Abstract: This invention provides a method for determining the concentration of a gas to be detected by a gas detector using a gas reactive pigment, wherein the dynamic range of the detectable concentration can be controlled. The method comprising bringing a gas to be detected such as a halogen gas, a hydrogen halide gas or the like into contact with a gas detector placed in a detection area and comprising a gas reactive pigment tetraphenylporphyrin or a derivative thereof represented by the general formula (1) or a metal complex of tetraphenylporphyrin or a derivative thereof represented by the general formula (2); and irradiating said gas detector with a detection beam and measuring a color change in said gas detector to determine the concentration of said gas to be detected, wherein the measurement is carried out in the temperature range from 40 to 80.degree. C. of said detection area; and a detection apparatus for carrying out the said method are disclosed.

Abstract: The present invention discloses a method for improving the speed and sensitivity of optical spectroscopic techniques for remote detection of trace chemical species in a carrier gas. The disclosed method can be applied to any optical spectroscopic detection technique whose sensitivity decreases as the total pressure of the sample decreases. The method employs an inert and non-absorbing buffer gas to supplement the pressure exerted by the carrier gas. This ensures that the total pressure of the sample, and hence sensitivity of the detection technique, remains high. The method is especially useful when measuring concentration of chemical species produced at small rates, and therefore should prove useful for rapid serial screening of combinatorial libraries of compounds.

Abstract: A method for detecting nitro-containing compositions (e.g. nitrate/nitrite materials) in water samples and on solid substrates. In a water sample, ultraviolet light is applied to the sample so that dissolved nitro compositions therein will photolytically dissociate into gaseous nitrogen oxides (NO.sub.2(g) and/or NO.sub.(g)). A carrier gas is then introduced into the sample to generate a gaseous stream which includes the carrier gas combined with any gaseous nitrogen oxides. The carrier gas is thereafter directed into a detector. To detect nitro-compositions on solid substrates, ultraviolet light is applied thereto. A detector is then used to detect any gaseous nitrogen oxides which are photolytically generated during ultraviolet illumination. An optional carrier gas may be applied to the substrate during illumination to produce a gaseous stream which includes the carrier gas and any gaseous nitrogen oxides. The gaseous stream is then supplied to the detector.

Abstract: When adsorbed gas is analyzed after metal, ceramics or metallic salt has been left in an environmental atmosphere for a predetermined period of time, an average concentration of specific gas over a long period of time can be accurately measured with an inexpensive small apparatus. Especially, porous metal or ceramics (transition metal oxide) are excellent in selective adsorption properties for NO.sub.x, porous ceramics (rare earth element oxide) are excellent in selective adsorption properties for CO.sub.2, and a specific chloride such as copper chloride and silver chloride is excellent in selective adsorption properties for SO.sub.2. A test kit accommodating such test pieces in a case, a protective case for the test kit to put the test kit into practical use, an umbrella and a forced air blowing unit are also disclosed.

Abstract: A method and apparatus for detecting NO.sub.x by chemiluminescence. The apparatus includes a sample gas line having an inlet port for receiving a sample gas, a NO.sub.x converter connected to the sample gas line, a N.sub.2 diluting gas line connected to the sample gas line upstream from the NO.sub.x converter, a bypass exhaust lie connected to the sample gas line, and a chemiluminescence analyzer connected to the NO.sub.x converter. The sample gas, which contains a NO.sub.x component, is introduced to the sample gas line through an inlet portion. The sample gas is diluted with nitrogen gas from the nitrogen diluting gas line, and the NO.sub.x component in the sample gas is converted to NO by the NO.sub.x converter. The chemiluminescence analyzer detects the NO.sub.x component.

Abstract: A sensor for oxidizing agents contains an oxidizable aromatic polymer. The sensor comprises a piezoelectric crystal coated with a porous or non-porous layer that contains the oxidizable aromatic polymer.