The optical concentration measuring device 1 includes: a first optical filter 41; a second optical filter 42; and an operation part 60, wherein a difference between a peak wavelength of the first effective sensitivity spectrum based on the first transmission band in the first light receiving part 51 and a peak wavelength of the second effective sensitivity spectrum based on the second transmission band in the second light receiving part 52 is ±0.2 times or more and ±0.8 times or less the full width at half maximum of the first effective sensitivity spectrum, wherein the operation part removes an attenuation amount of the first intensity by the interference gas and an attenuation amount of the second intensity by the interference gas.

Provided is a gas detection apparatus which suppresses occurrences of distortions of the optical path to reduce fluctuations of the gas detection sensitivity. A gas detection apparatus 1 includes a substrate 2; a light emitting element 3 disposed in a first region 21 in a main surface 20 of the substrate 2 for emitting light; a light receiving element 4 disposed in a second region 22 in the main surface 20 of the substrate 2 for receiving the light; a light guide member 5 for guiding the light emitted by the light emitting element 3 to the light receiving element 4; and a joint member 6 joining the substrate 2 and the light guide member 5. The joint member 6 serves as a rotation axis when the light guide member 5 is displaced relative to the substrate 2.

A system and method for determining impurities in a beverage grade gas such as CO.sub.2 or N.sub.2 relies on FTIR gas analysis for measuring non-sulfur impurities as well as SO.sub.2. CO.sub.2% also can be determined. A multiplexer selects a sample gas from multiple gas samples. Conversion of reduced sulphur present in some impurities to SO.sub.2 is conducted in an oxidizing furnace. Climate control and measurements of oxygen gas impurities also can be provided.

An electrically modulated light source is provided. The electrically modulated light source comprises a carbon nanotube film structure. The electrically modulated light source heats up to a highest temperature and emits thermal radiation in less than 10 milliseconds after a voltage is applied, and the electrically modulated light source cools down to an initial temperature of the electrically modulated light source in less than 10 milliseconds after the voltage is removed. An modulation frequency of the electrically modulated light source is greater than or equal to 150 KHz. A non-dispersive infrared spectrum detection system used the electrically modulated light source, and a method for detecting gas used the electrically modulated light source are also provided.

The optical concentration measuring device 1 includes: a first optical filter 41; a second optical filter 42; and an operation part 60, wherein a difference between a peak wavelength of the first effective sensitivity spectrum based on the first transmission band in the first light receiving part 51 and a peak wavelength of the second effective sensitivity spectrum based on the second transmission band in the second light receiving part 52 is ±0.2 times or more and ±0.8 times or less the full width at half maximum of the first effective sensitivity spectrum, wherein the operation part removes an attenuation amount of the first intensity by the interference gas and an attenuation amount of the second intensity by the interference gas.

A spectral imaging system configured to obtain spectral measurements in a plurality of spectral regions is described herein. The spectral imaging system comprises at least one optical detecting unit having a spectral response corresponding to a plurality of absorption peaks of a target chemical species. In an embodiment, the optical detecting unit may comprise an optical detector array, and one or more optical filters configured to selectively pass light in a spectral range, wherein a convolution of the responsivity of the optical detector array and the transmission spectrum of the one or more optical filters has a first peak in mid-wave infrared spectral region between 3-4 microns corresponding to a first absorption peak of methane and a second peak in a long-wave infrared spectral region between 6-8 microns corresponding to a second absorption peak of methane.

An absorption spectroscopic system is provided with a detector that detects an intensity of light transmitted through a gas, a total pressure sensor that measures a total pressure of the gas, an interference gas partial pressure-absorbance relationship storage unit that stores interference gas partial pressure-absorbance relationship data, an interference gas partial pressure estimation unit that estimates the partial pressure of the interference gas based on the total pressure measured by the total pressure sensor, an interference gas absorbance conversion unit that converts an estimated partial pressure of the interference gas estimated by the interference gas partial pressure estimation unit into an absorbance of the interference gas based on the interference gas partial pressure-absorbance relationship data, and a target gas absorbance calculation unit that calculates an absorbance of the target gas based on output values from the detector and on the absorbance of the interference gas.

The invention provides a gas detection system and a method with eliminating influence of ambient temperature and humidity change, the gas detection system comprises a bare sensor, a reference sensor and a calculation module; the bare sensor is used to detect a target gas in an ambient gas to obtain a first feedback signal; the reference sensor is used to selectively isolate the target gas in the ambient gas to produce a zero gas and to detect the zero gas to obtain a second feedback signal, the calculation module is used to calculate a difference between the first feedback signal and the second feedback signal to obtain a third feedback signal, and to obtain a target gas concentration by calculating the third feedback signal according to a calibration formula. The invention improves the measurement accuracy to the target gas concentration, which are efficient and reliable and have good technical effects.

An open path gas detector for detecting the presence of a target gas in the presence of fog or water vapor. A transmitter transmits flashes of optical energy along a path in an area under surveillance, including energy at a sample wavelength region at which the target gas is absorbed, at a reference wavelength region not significantly absorbed by the target gas, and at a synchronization wavelength region different from the first and second wavelengths. A receiver includes a sample channel responsive to the optical energy at the sample wavelength region, a reference channel responsive to optical energy at the reference wavelength region, and a third synchronization channel responsive to the optical energy at the synchronization wavelength region. The receiver detects the target gas and synchronizes operation of the receiver to the transmitter flashes of optical energy using the output of the synchronization channel.

The invention provides a gas detection system and a method with eliminating influence of ambient temperature and humidity change, the gas detection system comprises a bare sensor, a reference sensor and a calculation module; the bare sensor is used to detect a target gas in an ambient gas to obtain a first feedback signal; the reference sensor is used to selectively isolate the target gas in the ambient gas to produce a zero gas and to detect the zero gas to obtain a second feedback signal, the calculation module is used to calculate a difference between the first feedback signal and the second feedback signal to obtain a third feedback signal, and to obtain a target gas concentration by calculating the third feedback signal according to a calibration formula. The invention improves the measurement accuracy to the target gas concentration, which are efficient and reliable and have good technical effects.