1260 results about "Absorbance spectra" patented technology

The invention discloses a ppb-grade methane gas online detection method, equipment, a medium and a product, and relates to the field of data processing. The method comprises the following steps: acquiring an infrared absorption spectrum signal, and obtaining original spectrum data; performing multi-scale noise separation and baseline correction on the original spectral data to obtain de-noised effective spectral features, and extracting methane specific absorption peaks from the de-noised effective spectral features; comparing the methane specific absorption peak with the interference gas spectral line through a multi-spectral line weight matching algorithm to obtain methane characteristic intensity; carrying out self-adaptive calibration on the methane characteristic intensity according to the drift compensation model to obtain calibrated characteristic intensity; obtaining a ppb-level methane concentration value through a concentration inversion model; and inputting the sorted concentration time sequence data into an anomaly detection model to detect a methane leakage event. By designing signal processing and algorithm analysis, the dependence on equipment hardware performance is reduced, and the use cost of ppb-level methane gas detection is reduced.

The invention relates to the technical field of water pollution detection, in particular to a water quality pollution multi-dimensional analysis system which comprises the following steps: synchronously measuring an ultraviolet-visible absorption spectrum of a water sample to be detected and scattered light intensity in an orthogonal direction, and deducting spectrum baseline interference caused by suspended particulate matters in the water sample through a correction algorithm; the interferents in the water sample are selectively converted and degraded by applying a programmed potential to the inflowing water sample to be detected; the reverse pulse is periodically applied, so that the online regeneration function of the electrode is realized; analyzing the spectral data by adopting a multivariate correction algorithm, and calculating the concentration of the target pollutant; the calculation residual error of the multivariate correction algorithm is analyzed, new interference and system performance drift of current measurement are diagnosed, and a corresponding system state code is generated; and responding to the system state code, automatically starting and carrying out state checking and multi-point calibration on the instrument, and using a calibration result to update the analysis model. Through multi-dimensional perception and closed-loop operation, accuracy and reliability of water quality monitoring are guaranteed.

The invention relates to the technical field of mine safety, and discloses a coal mine underground gas monitoring method and system. The method comprises the following steps: acquiring methane absorption intensity data by adopting a tunable diode laser absorption spectrum, converting the methane absorption intensity data into gas concentration based on a Lambert-Beer law, performing temperature and humidity compensation, calculating a transmission priority according to concentration deviation to form a data packet, and establishing a spatial interpolation model by utilizing multipoint data to predict gas concentration distribution. Calculating a risk assessment index based on the predicted distribution, automatically adjusting the rotating speed of the ventilator, and controlling the electrical equipment to be powered off. According to the method, the technical problems of low detection precision, incomplete monitoring coverage, low data transmission efficiency and lack of prediction and early warning capabilities in the existing underground coal mine gas monitoring method are solved. And the accuracy of gas concentration detection and the intelligent level of gas monitoring are improved.

The invention relates to the technical field of spectrum water quality detection, in particular to a livestock breeding water quality detection method which comprises the following steps: acquiring absorption spectrum data of a livestock breeding water body, and acquiring a short-time fluctuation difference value of livestock breeding water at each measurement moment on each wave band absorption spectrum; the method comprises the following steps: based on the deviation between short-time fluctuation difference values of livestock breeding water in each wave band and other wave bands, acquiring short-time interference characteristic values of the livestock breeding water in absorption spectra in each wave band at each measurement moment, and combining spectral data differences of each measurement moment and a plurality of previous measurement moments in the same wave band; determining a water quality change coefficient of the absorption spectrum of each wave band; and according to the water quality change coefficient in combination with the short-time interference characteristic value, obtaining a water quality pollution evaluation value of the livestock breeding water at each measurement moment so as to judge the water quality condition of the livestock breeding water. The detection accuracy of the water quality of the livestock breeding water can be improved.

The invention relates to the field of data management, in particular to a VOCs pollution working condition data treatment method based on artificial intelligence. The method comprises the following steps: firstly, constructing a three-dimensional model of a factory, a pipeline and treatment equipment based on a BIM tool and a GIS technology, and deploying an Internet of Things sensor to collect VOCs pollution data; collecting original infrared absorption spectrum data of VOCs, and performing component identification by using a non-negative matrix factorization algorithm; a machine learning model is trained in combination with historical data, and short-term emission prediction is carried out; cooperative scheduling is carried out on the governance equipment through a multi-agent game optimization algorithm, and an optimal operation scheme is generated; constructing volume cloud modeling, and dynamically displaying an optimization effect; and if the predicted emission exceeds the standard, performing emission abnormity traceability analysis by using a graph neural network, and outputting a fault diagnosis report. According to the method, the VOCs emission prediction precision and the treatment efficiency are effectively improved.

The invention discloses an NO and SO2 mixed gas concentration detection method based on deep learning, and the method comprises the steps: obtaining a to-be-detected NO and SO2 mixed gas, inputting the to-be-detected NO and SO2 mixed gas into a trained mixed gas concentration detection model, and obtaining the concentration detection results of the respective single gases of NO and SO2; according to the model, mixed gas spectrum separation and reconstruction are carried out through a separation and reconstruction model based on a bidirectional long-short-term memory network, so that differential absorption spectrums of two single gases NO and SO2, which are output by the separation and reconstruction model, are obtained at one time; and carrying out feature extraction and concentration prediction on the input sequence data through a concentration detection model based on TCN + RNN network so as to obtain concentration detection results of respective single gases of NO and SO2 as outputs. The method provided by the invention can realize spectral separation of the mixed gas and accurate detection of the concentration of NO and SO2, thereby overcoming the problems of cross sensitivity of SO2 and NO and differential optics of incapability of accurately separating SO2 and NO by a traditional treatment method.

The invention discloses a ship carbon emission on-line monitoring method, device and equipment, and the method comprises the steps: building a comprehensive emission feature library through collecting infrared absorption spectrum, gas flow and other multi-source emission signals in a ship operation process; eliminating gas cross interference by adopting a spectrum separation analysis technology, and establishing a concentration inversion mechanism to generate an independent monitoring domain; high and low emission working condition modes are identified through working condition relevance evaluation, and intelligent allocation of monitoring resources is achieved; marine environment compensation nodes are established, layered temperature and humidity correction control is implemented, and environment-adaptive ship environment parameters are generated; the multi-stage early warning trigger time is determined by adopting an early warning threshold backward deduction analysis technology, a ship emission monitoring time sequence table and a graded monitoring instruction set are constructed, full-working-condition, all-weather and high-precision intelligent monitoring of ship emission is realized, and reliable technical guarantee is provided for ship environmental protection compliance and marine environmental protection.

The purpose of the present invention is to provide a technique for optically quantifying a compound of which a color does not change due to oxidative degradation.　Another aspect of the present invention provides a method for diagnosing oil characteristics, the method being characterized by: using an optical sensor having a light source and a detector that detects light emitted from the light source to acquire an absorption spectrum in a wavelength range of 800 nm to 3000 nm of an oil containing an additive having a maximum molar absorption coefficient value of 50 or less in the ultraviolet visible wavelength range of 250 nm to 800 nm; and inputting data based on the absorption spectrum into an estimation model implemented in an information processing device to predict the concentration of the additive.

The invention discloses a spectrum aliasing decoupling and concentration inversion method under the cross influence of multi-source environmental factors, belongs to the field of industrial process control and environment monitoring, and constructs an environment-spectrum collaborative fusion decoupling model for concentration prediction. The method specifically comprises the following steps: respectively collecting absorption spectrum signals of specified mixed gas at different temperatures, pressures and known concentrations, meanwhile, collecting environmental parameter data, constructing a multi-source data set, and carrying out denoising, dimension reduction and preprocessing on the multi-source data set; constructing a self-supervised feature extraction network for adaptive modulation of environmental parameters to realize deep fusion of spectrum and environmental information; the feature expression capability and generalization performance of the self-supervised feature extraction network are improved by using a self-supervised learning mechanism; and constructing a BPBO-GRNN self-adaptive concentration inversion optimization model for realizing inversion of mixed gas concentration and self-adaptive optimization of model parameters. According to the invention, high-precision concentration inversion and stable detection of the aliasing gas can be realized.

The invention provides a system and a method for off-line measurement of a cesium evaporation rate in a fusion device. The system comprises a vacuum chamber, a cesium crucible assembly, a heating assembly, a film thickness meter, a laser absorption spectrum system and a vacuum pumping unit. According to the invention, an ultrahigh vacuum environment is provided for the whole device including the vacuum chamber by using the vacuum pumping unit; then the cesium crucible and the conveying pipeline are heated through a heating assembly, so that effective evaporation of cesium is guaranteed, and deposition of cesium on the wall face of the pipeline is reduced; measuring the deposition thickness of cesium and the concentration of cesium atoms by using a film thickness meter and a laser absorption spectrum system, and checking the measurement results of the two diagnosis methods mutually; the cesium evaporation rate is measured, and the quantitative relation between the cesium evaporation rate and the heating temperature is obtained; and finally, a measurement system is transplanted into a negative ion source, and the cesium injection amount in the vacuum stage is monitored in real time. Effective data and technical support are provided for cesium flow control in the magnetic confinement nuclear fusion negative neutral beam injection system.

The invention discloses a transient absorption spectrum measurement system, method and device for polarized light, and relates to the technical field of ultrafast spectrum measurement. In the system, a laser generation device generates first laser and second laser, and the first laser is converted into left-handed circularly polarized light or right-handed circularly polarized light through a pump light polarization device to serve as pump light for exciting a sample to be detected; the first Glan prism converts the second laser into detection light which is linearly polarized in a specified direction so as to detect the sample to be detected; the first lambda / 4 wave plate is used for converting the detection light after detecting the to-be-detected sample into linearly polarized light with mutually vertical polarization; the Wollaston prism enables the linearly polarized light with mutually vertical polarization to be respectively transmitted to the measuring device along different directions; the measuring device calculates the transient absorption spectrum of the left-hand circularly polarized probe light and the transient absorption spectrum of the right-hand circularly polarized probe light. The system can simultaneously measure the transient absorption spectrums of the left-hand circularly polarized light and the right-hand circularly polarized light, so that the measurement error is reduced.

A multi-source water pollutant detection device based on multi-dimensional spectral information fusion comprises a base, a light shield, an electric signal detector, an absorption and fluorescence generation mechanism and a light filtering and light transmitting mechanism, the absorption and fluorescence generation mechanism and the light filtering and light transmitting mechanism are oppositely arranged on the base, and the light shield covers the base; the light filtering and transmitting mechanism comprises a plurality of light filters, through holes, light filter mounting fixing parts and photoelectric sensors; the photoelectric sensors are used for converting fluorescence signals filtered by the corresponding light filters and transmission light signals passing through the through holes into electric signals; the photoelectric sensors are connected with the electric signal detector; the absorption and fluorescence generation mechanism comprises a sample bin and a light source irradiation part for irradiating light sources with different wave bands in the sample bin, and a focusing part is arranged on the sample bin and used for focusing transmission light and fluorescence generated after irradiation and absorption of the light sources with the corresponding wave bands and irradiating the transmission light and the fluorescence to the through hole in the light filter mounting and fixing part and the light filter. According to the utility model, the advantages of absorption spectrometry and three-dimensional fluorescence spectrometry are fused, and rapid detection of pollutants is realized.

The invention belongs to the technical field of flow field optical measurement, and particularly relates to a high-enthalpy plasma gas temperature measurement method, system and device based on an absorption spectrum. Generating a composite modulation signal through a high-frequency sine wave and a low-frequency sawtooth wave, and enabling incident light to pass through a flow field measurement area in parallel through laser modulation and beam shaping; the detector receives the transmission light and converts the transmission light into an electric signal containing harmonic information, the signal acquisition device is used for performing signal acquisition, the phase-locked demodulation algorithm is used for extracting second harmonic, and the temperature is inversely deduced by combining the double-spectral-line temperature measurement method and the Fourier coefficient amplitude ratio of the second harmonic with the HITRAN database. The system comprises a signal driving module, a laser emission module, a detection acquisition module and a temperature measurement module. The device is composed of a signal generator, an in-phase adder and the like, and a laser is matched with a driving power supply to guarantee stable work. According to the scheme, aiming at the problems of weak signal absorption and insufficient signal-to-noise ratio under complex working conditions, the measurement accuracy and reliability are improved by composite modulation, harmonic extraction and a bispectral line algorithm, and an effective means is provided for research on thermal characteristics of the high-enthalpy plasma.

The invention discloses a molecular probe for in-vivo copper ion detection and a preparation method and application thereof, the chemical structural formula of the molecular probe is as follows: # imgabs0 #, the molecular probe provided by the invention can specifically respond to copper ions in a tumor subacid environment so as to cause change of an absorption spectrum, and a photoacoustic signal is started so as to detect the copper ions in the tumor subacid environment. Normal tissues and tumor tissues can be accurately distinguished, and accurate detection of the copper ions in the living tumor is realized.

The invention discloses a water sample pollution traceability analysis method fusing absorption-three-dimensional fluorescence spectrum characteristics, and relates to the field of water sample spectrum analysis traceability. According to the method, high-precision prediction of pollutant indexes is realized by utilizing multi-dimensional information of a three-dimensional fluorescence spectrum and an absorption spectrum of a water sample, qualitative and quantitative traceability of main pollution components and potential emission sources in a water body is carried out based on correlation analysis of the prediction indexes, a pollutant feature library and an emission source database, and the method has the advantages of high accuracy and high accuracy. The integration of water quality monitoring and pollution source management is realized, and a systematic and real-time technical means is provided for pollution analysis of a complex water body.

To provide polyimide as an insulation material for preparing a printed circuit board.SOLUTION: Polyimide includes one or a plurality of repeating units derived from dianhydride, and one or a plurality of repeating units derived from diamine. Infrared absorption spectrum of the polyimide obtained through Fourier transform infrared spectroscopy (FTIR) using attenuated total reflection (ATR) has a characteristic peak A of 1,753 cm-1 to 1,803 cm-1, a characteristic peak B of 1,635 cm-1 to 1,752 cm-1, and a characteristic peak C of 1,160 cm-1 to 1,170 cm-1, the characteristic peak A has a characteristic peak area a, the characteristic peak B has a characteristic peak area b, the characteristic peak C has a characteristic peak area c, b / a is 25.00 or less, and c / b is 0.3000 or more.SELECTED DRAWING: None

The invention discloses a space-space-ground-well integrated carbon dioxide sequestration leakage monitoring method and system, and relates to the technical field of carbon dioxide sequestration leakage monitoring, and the method comprises the steps: carrying out the remote sensing measurement of a target region through a synthetic aperture radar and a satellite, and determining a carbon dioxide sequestration leakage monitoring boundary; performing photogrammetry by using an unmanned aerial vehicle, and constructing a three-dimensional real scene model Surveying the target area on site to obtain surveying and mapping data; based on the key monitoring area, an absorption spectrum and earth surface leakage flux are obtained through infrared spectrum monitoring and vorticity monitoring; gravity monitoring data, storage area underground water parameters, carbon dioxide plume distribution conditions and logging sound wave frequency distribution characteristic graphs are obtained through gravity monitoring, underground water monitoring, optical fiber monitoring and sound wave logging monitoring. And through comprehensive analysis, according to a comprehensive analysis result, whether carbon dioxide leaks is judged, and a carbon dioxide sequestration leakage monitoring result is obtained. The accuracy of carbon dioxide sequestration monitoring can be effectively improved.

The invention provides a mineralogical substance composition testing method and system based on multispectral data fusion. The method comprises the following steps: separating out a first characteristic interference signal caused by the oxidation state of an iron element and a second characteristic interference signal caused by the oxidation state of a manganese element by adopting wavelet transform in a superposition region of a Raman spectrum signal and a visible light absorption spectrum; performing spatial weighting on the intensity of the first feature interference signal and the intensity of the second feature interference signal to construct a multi-dimensional feature vector, inputting the multi-dimensional feature vector to a pre-trained residual neural network, and combining a radioactivity attenuation parameter measured by a gamma spectrometer to determine the radioactivity attenuation of the first feature interference signal and the second feature interference signal. And generating a mineralogical substance composition test result containing a mineral phase, an isomorphic substitution ratio, color cause analysis data and a radiation safety level. According to the method, the collaborative interpretation of the multispectral data and the radiation parameters can be realized, the mineral component analysis precision is improved, the color formation mechanism is synchronously analyzed, and the radioactive risk level is quantitatively evaluated.

The invention discloses a mixed gas absorption spectrum analysis method and system based on variational mode decomposition, specific laser is injected into an optical resonant cavity unit, and a detector unit continuously monitors the light intensity change and records a light intensity attenuation signal; pre-processing the recorded light intensity attenuation signal; carrying out VMD decomposition on the preprocessed ring-down signal to obtain a plurality of IMF components, respectively introducing CO2 and CO gases with known concentrations into the optical resonance unit, and recording spectral data of each single gas component; calculating the similarity and contribution degree of each IMF component, and setting a weight combination to form a joint score; the gas with the highest joint score is selected, the score is compared with an adaptive threshold value, and when the score is higher than the adaptive threshold value, the IMF component is marked as the characteristic component of the corresponding gas; and finally, gathering and outputting the marked IMF components according to gas types to obtain characteristic signals of the gases, thereby realizing multi-component gas separation in the mixed gas absorption spectrum.

The invention relates to the technical field of gas concentration calculation, in particular to an anti-interference broadband cavity enhanced absorption spectrum inversion algorithm. On the basis of a traditional cavity enhanced absorption spectrum algorithm, a pseudo-absorption function is constructed and used for representing a non-gas absorption structure caused by lamp spectrum deformation in the gas concentration inversion process, so that interference caused by lamp spectrum deformation is separated from the gas absorption structure, and the gas concentration inversion accuracy is improved. The influence of lamp spectrum deformation on a gas concentration inversion result is effectively avoided, the dependence of a traditional cavity enhancement algorithm on the absolute stability of a light source is overcome, and the gas concentration can be accurately quantified. According to the method, the robustness and environmental adaptability of the broadband cavity enhanced absorption spectrum system can be effectively improved.

The invention discloses a detection system of an absorption spectrum water quality multi-parameter analyzer, and relates to the field of water quality detection. Comprising a water sample acquisition and self-adaptive preprocessing module, a full-spectrum dynamic acquisition and waveband optimization module, a multi-dimensional data fusion processing module, a dynamic evolutionary model training and optimization module, an intelligent pollution traceability and parameter inversion module and a real-time decision and early warning response module. According to the detection system of the absorption spectrum water quality multi-parameter analyzer, through multi-dimensional data fusion, a dynamic evolution model and a spectrum fingerprint traceability technology, the pollutant concentration can be accurately inverted, the pollution source can be rapidly positioned, and the diffusion trend is predicted in combination with hydrological-meteorological data; graded early warning and customized disposal suggestions are synchronously generated, and the environmental protection supervision platform and the treatment terminal are linked through the Internet of Things, so that closed-loop response of detection, source tracing, early warning and disposal is realized.

The invention provides a gaseous pollutant Fourier transform infrared spectroscopic analysis method based on deep learning. The gaseous pollutant Fourier transform infrared spectroscopic analysis method comprises the following steps: acquiring infrared absorbance spectrums of different gases to be detected by utilizing a Fourier transform infrared gas analyzer; the method comprises the following steps of: preprocessing the collected spectral data, namely carrying out segmented denoising on the original spectral data by adopting a self-adaptive Savitzky-Golay filter, and carrying out normalization processing to balance a data range; carrying out feature extraction on the preprocessed spectral data by utilizing a one-dimensional convolution deep learning model so as to adapt to one-dimensional FTIR spectral features and realize feature extraction of multiple components of gas; mapping the extracted features to a prediction result of the to-be-detected component by applying a full connection layer of the model; and training and optimizing the model by adopting an MSE regression loss function. According to the invention, the processing capability of the gaseous pollutant spectral signal can be effectively improved, and high-precision multi-component quantitative analysis is realized.

The invention relates to the technical field of water vapor concentration detection, and discloses a water vapor concentration online detection method and system based on a multi-wavelength infrared absorption spectrum, and the method comprises the steps: controlling an infrared light source module to emit pre-modulated light, enabling the pre-modulated light to pass through a gas chamber module, inputting the pre-modulated light into a photoelectric detection module, and converting the pre-modulated light into a sample electric signal; acquiring temperature data and pressure data at a preset position of the air chamber module in real time; calculating to obtain an initial differential absorption signal by using the sample electric signal and combining a Lambert-Beer law; based on the temperature data and the pressure data, performing temperature and pressure dynamic compensation on the initial differential absorption signal by using a pre-stored compensation database to obtain a target differential absorption signal; and determining the water vapor concentration according to the target differential absorption signal. According to the invention, the effects of improving the measurement precision and the measurement stability of the water vapor concentration and measuring the water vapor concentration online in real time can be achieved.

The invention discloses an insulation paper aging state evaluation method and device, equipment, a medium and a product, and relates to the technical field of insulation paper aging state evaluation. Carrying out terahertz time-domain spectroscopy test on the aged insulation paper sample to obtain a terahertz time-domain spectroscopy signal of the aged insulation paper sample; fourier transform is carried out on the terahertz time-domain spectral signal to obtain a terahertz frequency-domain absorption spectrum of the aged insulation paper sample, and optical parameters of the aged insulation paper sample in a terahertz frequency band are extracted; based on the Pearson's related absorption theory, using optical parameters to propose an aging characteristic quantity with absorption spectrum similarity as a characteristic, and calculating a similarity value between the aging sample insulation paper and a reference; and evaluating the aging condition of the to-be-tested insulation paper in the oil paper insulation system according to the similarity value. According to the invention, a new idea is provided for accurate and lossless evaluation of the aging state of the insulation paper in the oil paper insulation system.

The methods described herein provide improvements in composite infrared absorption imaging. The scanning approach described herein reduces erroneous measurements caused by thermal drift and optical interference that occurs between light scattering from the top surface of the sample and light scattering from the underlying substrate. Embodiments described herein relate to imaging and spectroscopy, and more particularly, to improvements in photo-thermal imaging and spectroscopy systems, and techniques for obtaining spectral information characterizing optical properties and / or materials or chemical compositions of a sample, such as information related to infrared (IR) absorption spectroscopy.

The invention relates to the technical field of gas detection, and discloses a high-sensitivity sulfur hexafluoride detection method and a high-sensitivity sulfur hexafluoride detection system based on cooperation of a long-wave infrared absorption spectrum and a thermal infrared spectrum, which are used for solving the problem that water vapor in a detection area affects a sulfur hexafluoride detection result during sulfur hexafluoride detection. The method comprises the following steps: acquiring long-wave infrared absorption spectrum data and environment abnormal data, acquiring an infrared radiation space distribution diagram of a to-be-detected area, acquiring environment humidity and dew point temperature, obtaining initial detection concentration of sulfur hexafluoride according to the long-wave infrared absorption spectrum data, and calculating the concentration of sulfur hexafluoride according to the environment abnormal data, the environment humidity and the dew point temperature. The method comprises the following steps: acquiring an environmental water vapor influence index through evaluation, performing water vapor interference judgment, and if judging that water vapor interference exists in a current detection environment, correcting an initial detection concentration according to the environmental water vapor influence index to obtain an actual detection concentration, thereby effectively improving the accuracy of a sulfur hexafluoride detection result and reducing the problems of missing detection and false detection.

A system that reduces the buildup of film on a movable shaft that enters and is retracted from a process chamber is disclosed. A ring heater is disposed around the shaft inside the process chamber proximate the air bearing. The ring heater includes a plurality of optical energy emitters arranged around the shaft. The wavelength emitted by the ring heater may be selected to align with the absorption spectrum of the film. In this way, the optical energy serves to heat the film and lower the tendency for the film to adhere to the movable shaft and enter the air bearing.

The present invention relates to the technical field of hydrogen concentration detection, and specifically discloses a trace hydrogen concentration sensing system based on TDLAS absorption spectroscopy, which is used to solve the problems of low detection sensitivity, narrow linear range, large system drift and dependence on external calibration in TDLAS hydrogen detection. The system comprises a laser emission module and a photoelectric detection module, wherein the laser emission module and the photoelectric detection module are connected via a dual-light path absorption module, the photoelectric detection module is connected to a harmonic extraction module, the harmonic extraction module is connected to a normalization processing module, and the normalization processing module is connected to a concentration inversion module. The present invention realizes high linearity, high sensitivity, and calibration-free concentration detection of hydrogen within 0.01% to 100% by constructing a symmetrical dual-light path structure, adopting a harmonic signal normalization and differential compensation algorithm, and combining a high-pressure reference gas cell with a segmented fitting model, thereby improving the trace hydrogen identification capability.

An apparatus and method of determining the concentration of first and second substances within a sample by exposing the sample to radiation and filtering the radiation transmitted from the sample using a first filter having a number of pass bands at wavelengths corresponding to absorption peaks in a desired quasi-periodic absorption spectrum of the first substance to be detected, and modulating the wavelengths of the pass bands of the first filter. Additionally, filtering the radiation transmitted from the sample using a second filter having a number of pass bands at wavelengths corresponding to absorption peaks in a desired quasi-periodic absorption spectrum of the second substance to be detected, and modulating the wavelengths of the pass bands of the second filter. The concentration of the first and second substances is determined by determining the difference in the maximum and the minimum intensities of the radiation transmitted by the sample.

The invention discloses a natural gas calorific value test result correction method, system, equipment and medium, and relates to the technical field of natural gas analys.The method comprises the steps that according to the initial calorific value, the carbon dioxide content and the relative density obtained through testing and pressure data and temperature data of a test point, the first nitrogen content is obtained through calculation based on an S-GERG88 state equation; calculating a first calorific value by using the first nitrogen content and the initial calorific value, and performing iterative calculation according to the first calorific value to obtain a second nitrogen content until the absolute value of the difference between the second nitrogen content and the first nitrogen content is smaller than a preset value; determining the first calorific value corresponding to the obtained second nitrogen content as a target calorific value; through an iterative algorithm, the accuracy of a natural gas calorific value test result and a natural gas working condition compression factor calculation result through the laser absorption spectrometry can be greatly improved, and then the path reliability and applicability of natural gas energy metering through the laser absorption spectrometry are improved.