34 results about "Differential optical absorption spectroscopy" patented technology

The invention discloses a low-concentration, multi-component and high-sensitivity gas detection method based on integration of multiple spectrum technologies. Advantages of an ultraviolet differential optical absorption spectroscopy (DOAS) technology and an infrared tunable diode laser absorption spectroscopy (IR-TDLAS) technology are integrated, so that information integration and characteristic signal extraction of two kinds of spectrum are realized. The method disclosed by the invention is used for measuring the NH3 concentration in smoke by utilizing a TDLAS method and simultaneously measuring the concentrations of SO2 and NO2 in smoke by utilizing an ultraviolet DOAS method; interference of three components in the NO absorbancy is removed according to the obtained concentrations and an interference spectrum of three kinds of gas to the NO absorbancy, so that the NO concentration without cross interference is solved; and thus, the measurement precision and the detection lower limit are greatly increased.

The invention provides a differential absorption spectrum air quality inspecting system, which comprises a photo source, a photo source launching device, a photo source receiving device, a spectroscope, photovoltaic conversion equipment and a data processing system. The photo source launching device and the photo source receiving device are separately positioned on the two sides of the photo source, a light path which goes through the gas to be inspected is formed of the light sent out by the photo source through the photo source launching device and the photo source receiving device, and the light signal produced is imported into the spectroscope through optical fiber, and the light signal is then transformed into electrical signal through the photo electricity commutating equipment; Finally, the data processing system adopts the signal analysis method of the Fourier transformation to process the spectrum, and the absorbance curve line of the gas inspected is obtained; and the density of the gas inspected can be obtained according to the intensity of the absorbance curve line and the Lambert-beer law.

The invention relates to a method for measuring gas component concentration in an inverse calculation mode based on a differential optical absorption spectrum. In the method for measuring the gas component concentration in the inverse calculation mode based on the differential optical absorption spectrum, a mathematic model is established and solved by a least square method, the contents of various pollutants in flue gas can be recorded in real time, and the gas which comprises unknown components can be determined. Meanwhile, the invention provides a solution scheme aiming at main factors which influence the precision of differential optical absorption spectroscopy (DOAS), analysis errors due to spectral line shift can be effectively reduced, and the precision problem of the gas component concentration measurement in which absorption spectral lines are superposed is solved.

The invention discloses an OH free radical measurement calibration system by adopting fluorescence assay by gas expansion. The OH free radical measurement calibration system comprises a wideband light source, a water vapor generation part, an OH free radical generation part and a signal collection part, wherein the OH free radical generation part comprises an aluminum cavity, a U-shaped air inlet pipe, a multiple-reflection cell, a quartz sleeve and a high power ultraviolet lamp. The OH free radical calibration system disclosed by the invention can integrate generation and measurement of OH free radicals, and the concentration of the generated OH free radicals is measured by adopting a differential optical absorption spectroscopy (DOAS), so that the accuracy of the measured concentration of the OH free radicals is improved; the concentration of the OH free radicals is measured by adopting an optical method, the collection system is simple, and convenient and easy to operate; the wideband light source is adopted by the OH free radical calibration system disclosed by the invention, and visible light in the light source is used as an indication and adjustment light source of 308nm to solve the problem that the optical distance of the multiple-reflection cell is hard to measure due to the invisibility of 308nm.

The invention provides a portable gas monitor for monitoring volatile organic compounds by using differential optical absorption spectroscopy, comprising a heating sampling probe, a heating sample conveyer, a heating detecting gas chamber, a light source, a spectrometer, a GPRS (general packet radio service) positioning and data transmission unit, a flow metering and exhausting device, and a computer control system; the heating sample conveyer is connected with the heating sampling probe and the heating detecting gas chamber; light from the light source enters the heating detecting gas chamber and is reflected by a DOVE prism to enter the spectrometer; a mass flow meter of the flow metering and exhausting device is connected with an exhaust nozzle of the heating detecting gas chamber, and flow and on-off of a sampling pump are automatically controlled by the computer control unit; the computer control system uses received data to calculate characteristic signals of gas absorption by using differential difference technique to obtain gas concentration; the accuracy and sensitivity of detection results can be improved through DOVE prism reflection, gas concentration correction and differential difference technique.

The invention discloses a UAV (unmanned aerial vehicle) loading based DOAS (differential optical absorption spectroscopy) detection method for high-emission typical pollutants. When high-emission gasenters a gas chamber, a control center turns on a light source, light emitted by the light source enters the gas chamber, light coming out of the gas chamber enters a spectrograph, the spectrograph collects a spectrum, and the control center stores data in data storage equipment. The method is high in precision, pollutants are measured with DOAS, and high precision is realized as compared with physical or chemical detection. The requirement for upper detection limit of a detection device is high in a specific environment such as a high-emission enterprise, and the problem can just be solved with spectroscopy. Next, high altitude pollution of a high-emission enterprise environment can be monitored at any time with the method, a UAV is used as a carrier, air pollution condition especially insurrounding of the high-emission enterprise can be obtained quickly in real time, and the method can be used by a supervision department for remote monitoring. Finally, an independently researched and developed operation system is provided, and real-time control can be realized through an electronic screen.

The invention provides a differential optical absorption spectroscopy (DOAS) measurement system based on an off-axis paraboloid mirror. The DOAS measurement system comprises an off-axis paraboloid mirror (center punched) telescope, a light source (LED) device, a light source coupling lens, a light source collimating lens, a corner reflector, an optical fiber and a spectrograph detector. Light emitted from the light source device is coupled by a lens to enter the optical fiber, enters atmosphere through a small hole in the center of the off-axis paraboloid mirror after being collimated by the collimating mirror, returns the off-axis paraboloid mirror telescope after being reflected by the corner reflector through a certain distance of transmission, enters a receiving optical fiber through off-axis convergence and coupling and transmitted to the spectrograph, and is received by the detector after being split by the spectrograph, thereby being subjected to post-stage spectrum analysis. Compared with a conventional DOAS system, the DOAS measurement system provided by the invention has the advantages that the receiving efficiency of the telescope is increased, and the system is simplified to ensure that receiving an optical signal and emitting an optical signal are separated to facilitate the system adjustment through designing a simple structure inside the telescope.

The invention relates to a multi-LED combination broadband light source device based on a multi-edge reflection cone, and relates to the designing field of broadband light sources suitable for the spectrum analysis. The problems that in an existing spectrum analysis, power consumption is high and the service life is short by adopting a xenon arc lamp and other broadband thermal light sources, and a spectrum coverage wave band is too narrow by utilizing a single LED cold light source are solved. A plurality of efficient LEDs with different peak wavelengths are adopted to be combined, an optical system is formed by the efficient LED combination, the off-axis cast surface multi-edge reflection cone and an aspheric surface single lens, the LEDs can be efficiently combined, the combined broadband light source has the advantages that power consumption is small, the service life is long, energy is saved, environmental protection is facilitated, and the spectrum wave band range can be widened according to the demands, the multi-LED combination broadband light source device is suitable for the spectrum analysis application and especially suitable for a broadband light source needed by the differential optical absorption spectroscopy technology, and accuracy measurement of various trace gases can be carried out on multiple spectrum wavebands at the same time.

The present invention relates to a high sensitivity optical system of a differential optical absorption spectroscopy (DOAS) analyzer for gas concentration detection. According to the system, two optical axes of a collimating lens set and a condenser lens set intersect on a side of a large lens to form the optical axis intersection point, wherein the collimating lens set is arranged perpendicular to the condenser lens set; optical axes on both sides of the collimating lens set are respectively provided with a light source and a transmitted light reflector; optical axes of both sides of the condenser lens set are respectively provided with an optical fiber spectrometer and a reference light reflector; a spectroscope plated with a reflecting film is positioned on an angular bisector of a right angle, wherein the optical axes of the two adjacent sides of the collimating lens set and the condenser lens set intersect to form the right angle; the spectroscope is concurrently and obliquely arranged on the optical path comprising the half outgoing beam of the collimating lens set and the half incoming beam of the condenser lens set in the angle of 45 DEG, and the other half outgoing beam of the collimating lens set and the other half incoming beam of the condenser lens are provided with moveable baffles, wherein the positions of the movable baffles are switchable; the half of the beam emitted by the light source enters the reference light path, and the other half of the beam enters the measurement light path. According to the present invention, under the same light source radiationconditions, the light energy passing through the optical system of the present invention is strong, the signal-to-noise ratio is high, and the measurement precision is improved.

The invention discloses an integrated DOAS (differential optical absorption spectroscopy) gas analyzer for monitoring multicomponent poisonous and harmful gases of gardens. The integrated DOAS gas analyzer comprises a gas detection part and a gas analyzing part, the gas detection part comprises a telescope, a calibration control box, an optical corner reflector, a diaphragm and a self-correcting lens; a mercury lamp and a mercury lamp lifting motor are arranged in the calibration control box; the calibration control box is located ahead of the telescope, and the diaphragm, the self-correcting lens and the optical corner reflector are sequentially arranged in the rear of the telescope; the gas analyzing part comprises a case, a main control panel, a heat preservation box, a mercury lamp power supply board connected with the main control panel, an upper computer, a spectrograph, a temperature sensor, a heating piece and a status indicator lamp, and the spectrograph, the temperature sensor and the heating piece are arranged in the heat preservation box; the air detection part and the air analyzing part are connected through an optical fiber. The integrated DOSA gas analyzer is highly integrated, simple in operation and stable and reliable, and poisonous and harmful gases in the gardens can be monitored accurately and effectively.

The invention provides an optical fiber transceiver integrated air differential optical absorption spectroscopy (DOAS) measuring system, which solves the problems of low spectrum utilization ratio and difficulty in instrument adjustment and optical path centering of the existing typical DOAS system. The measuring system comprises a point light source, a telescope, a spectrograph and an optical fiber bundle with a transceiver integrated structure, wherein, the optical fiber bundle with the transceiver integrated structure is composed of transmitting optical fiber and receiving optical fiber and provided with an optical fiber transceiver common port. The spectrum sent by the point light source is transmitted through the optical fiber transceiver common port from one end of the transmitting optical fiber, aligned through a spherical reflector in the telescope, reflected along the original direction after reaching a pyramid prism, focused through the spherical reflector and then enters the optical fiber transceiver common port, and finally transmitted through the other end of the receiving optical fiber and then led into the spectrograph for spectrum detection. Compared with the typical DOAS system, the measuring system reduces two plane reflectors, avoids a light beam being sheltered by the plane reflector during the transmission process, improves the spectrum utilization ratio and simplifies the instrument adjusting and centering process.

The invention provides a pollution-gas differential optical absorption spectroscopy measurement system with optical fiber structure. The measurement system is characterized in that a xenon lamp light source is disposed in a lamp holder; light beams emitted by the xenon lamp light source are coupled to the transmitting optical fibers connected with the lamp holder; the first bundle of the optical fibers of the transmitting optical fibres are connected with a first optical switch; the second bundle of the optical fibers of the transmitting optical fibers are connected with a transmitting/receiving telescope; the second light beam penetrates through the optical switch and then is used as a background spectrum and enters in receiving optical fibers; the first light beam is transmitted after being reflected by a plane mirror of the transmitting/receiving telescope, reflected via a corner reflector, then received by the transmitting/receiving telescope and coupled to the receiving optical fibers; the receiving optical fibers penetrate through a second optical switch and a sample box and then are connected with a spectrograph; the first light beam and the second light beam are coupled by the receiving optical fibers to form the third light beam; the third light beam is received by the spectrograph; the spectrum of the third light beam is monitored by the spectrograph; and content information of the pollution gas is obtained by a data processing system according to monitored results. The measurement system is liable to disassemble and assembly, and is compact in structure and high in spectrum utilization rate.

The invention discloses a data processing method for an ultraviolet differential gas analyzer. The method comprises the following steps: acquiring dark spectrum data; acquiring source spectrum data of detected gas; performing nonlinear compensation correction on the source spectrum data with the dark spectrum data and the source spectrum data as parameters, thereby obtaining target spectrum data; calculating the pseudo concentration value of the detected gas corresponding to the target spectrum data by a differential optical absorption spectroscopy method; and calculating the concentration value of the detected gas which the pseudo concentration value corresponds to according to a stepped judgment method. On one hand, the method disclosed by the invention can reduce noise effect on a spectrometer brought about by temperature, humidity and the like and ensures the reliability of data, and on the other hand, the method reduces the influence on high concentration gas and low concentration gas brought about by detection environments and improves the detection precision. In addition, the invention further discloses a data processing system for the ultraviolet differential gas analyzer.

The invention relates to a portable detector for sulfur dioxide content in exhaust gas discharged from a ship chimney. The portable detector comprises an ultraviolet light source, a light transmission optical fiber, an openable gas sensing head, an ultraviolet spectrograph, an embedded computer, a power source and a mainframe box. The ultraviolet light source, the ultraviolet spectrograph, the embedded computer and the power source are placed in the mainframe box. The openable gas sensing head and the mainframe box are connected only through the light transmission optical fiber for light transmission. The power source supplies power to the ultraviolet light source, the ultraviolet spectrograph and the embedded computer. According to the portable detector, a differential optical absorption spectroscopy and an ultraviolet continuous spectrum analyzing method are used for detection, and without influences of moisture and particles and other gases in the ship exhaust gas, a measuring result is more stable.

The invention belongs to the technical field of optical measurement and specifically relates to an LED light source-based differential optical absorption spectroscopy system for measuring concentration of glyoxal in the atmosphere. The system of the invention is composed of an LED light, a plane mirror, a main concave mirror, an optical corner reflector, a secondary mirror, a fiber, a spectrometerand a computer, etc. A virtual image generated by the LED light in the plane mirror is positioned near the focus of the main concave mirror; after collimation by the main concave mirror, light beamsenter the atmosphere and reach the optical corner reflector after transmitted for some distance; the light beams are reflected back to the main concave mirror along the original path and are gatheredto the fiber after focusing by the secondary mirror; after light splitting by a spectrometer and photoelectric conversion, absorption spectrum information is obtained; by the least square method for spectral interpretation, the calibrated NO2 standard absorption spectrum is used as a fitting item for inversion of glyoxal to reduce the interference of NO2 with analysis of glyoxal, thereby achievingaccurate measurement of concentration of glyoxal in the atmosphere.

The invention discloses a full-automatic calibration control system for a long-optical distance DOAS (Differential Optical Absorption Spectroscopy) gas analyzer and a calibration method thereof. The full-automatic calibration control system comprises an automatic control module, a sample tank hoisting module, a mercury lamp hoisting module, a diaphragm motor module and upper computer software, wherein the automatic control module and the upper computer software are communicated so as to realize the control on the sample tank hoisting module, the mercury lamp hoisting module and the diaphragm motor module. The full-automatic calibration control system has the beneficial effects that all the modules are fully automatically controlled by RS485 communication. An optical coupler is used for positioning hoisting positions of a sample tank and a mercury lamp and the accuracy is very high. The sample tank does not need to be moved and replaced and only concentrations and types of gases in the sample tank need to be replaced, so that system calibration light paths of each time are the same. The full-automatic calibration control system is compact in structure of the single module, convenient to use, high in position accuracy and good in stability, and can be used for realizing the full-automatic control of DOAS system calibration.

The invention discloses a multiaxial scanning device based on scattered light passive differential optical absorption spectroscopy. The multiaxial scanning device comprises a telescope height scanningmechanism, a camera height scanning mechanism, an azimuth scanning mechanism and a telescope receiving system, wherein a telescope height scanning mechanism emergence window and a camera height scanning mechanism emergence window are respectively coaxially connected with an azimuth scanning box body telescope incidence window and a camera incidence window; a telescope height scanning mechanism emergence optical axis and a camera height scanning mechanism emergence optical axis are respectively coaxial to an azimuth scanning mechanism telescope incidence optical axis and a camera optical axis,and are coaxial to a height rotation axis; the azimuth scanning mechanism is mounted on the telescope receiving system; an azimuth scanning mechanism emergence window is coaxially connected with a telescope receiving system incidence window, an azimuth scanning mechanism emergence optical axis is coaxial to a telescope receiving system optical axis and is coaxial to an azimuth scanning mechanismrotation axis. The multiaxial scanning device has the characteristics of simple tinstallation, low cost and high scanning precision, and can be widely applied to automatic monitoring of atmospheric pollutants in a troposphere.