CN107478601A - Gas concentration detection system and detection method based on Wavelength modulation spectroscopy - Google Patents
Gas concentration detection system and detection method based on Wavelength modulation spectroscopy Download PDFInfo
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- G—PHYSICS
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- G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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Abstract
The present invention relates to the gas concentration detection system based on Wavelength modulation spectroscopy,The sine wave signal output end connection adder of its first signal generator,The triangular signal output end connection adder of secondary signal generator,The signal output part connection pulse width modulator of adder,The signal output part connection laser driver of pulse width modulator,The laser-driven signal input connection distributed feedback laser of laser driver,The laser signal output end face of distributed feedback laser detects the laser signal entrance port of air chamber to gas concentration,Laser signal exit wound of bullet of the signal input part of laser detector towards gas concentration detection air chamber,The signal input part of the laser induced signal output part connection processor of laser detector,The cosine wave signal output end connection lock-in amplifier of first signal generator,The signal output part connection processor of lock-in amplifier,The triangular signal output end connection processor of secondary signal generator.Energy accurate measurement gas concentration of the invention.
Description
Technical field
The present invention relates to technical field of photo communication, and in particular to a kind of gas concentration detection system based on Wavelength modulation spectroscopy
System and detection method.
Background technology
Existing gas concentration detection system, the modulator approach of used light source is for single triangular wave or individually just
String ripple is modulated, and the adjustment mode of this light source can not provide and modulated signal (single triangular wave or individually just in demodulation
String ripple) into 90 degree of demodulated signals, therefore the modulation accuracy of this modulation of source is not high, so as to have impact on gas concentration detection system
The precision of the Concentration Testing result of system.
The content of the invention
It is an object of the invention to provide a kind of gas concentration detection system and detection method based on Wavelength modulation spectroscopy,
The system and method energy fast and accurate measurement gas concentration.
A kind of in order to solve the above technical problems, gas concentration detection system based on Wavelength modulation spectroscopy disclosed by the invention
System, it is characterised in that it includes the first signal generator, secondary signal generator, adder, pulse width modulator, Laser Driven
Device, distributed feedback laser, gas concentration detection air chamber, laser detector, lock-in amplifier and processor, first letter
First signal input part of the sine wave signal output end connection adder of number generator, the triangular wave letter of secondary signal generator
The secondary signal input of number output end connection adder, the signal of the signal output part connection pulse width modulator of the adder
Input, the signal input part of the signal output part connection laser driver of pulse width modulator, the Laser Driven of laser driver
Signal output part connects the driving signal input of distributed feedback laser, the laser signal output of distributed feedback laser
End face detects the laser signal entrance port of air chamber to gas concentration, and the signal input part of laser detector detects towards gas concentration
The laser signal exit wound of bullet of air chamber, the signal input part of the laser induced signal output part connection processor of laser detector, the
The signal input part of the cosine wave signal output end connection lock-in amplifier of one signal generator, the signal output of lock-in amplifier
The demodulated reference signal input of end connection processor, the triangular signal output end connection processor of secondary signal generator
Demodulated signal input.
A kind of gas concentration detection method using said system, it comprises the following steps：
Step 1：Sine wave signal of first signal generator to adder frequency of delivery scope for 100Hz~100kHz,
Triangular signal of the secondary signal generator to adder frequency of delivery scope for 1Hz~1kHz；
Step 2：Adder will be defeated to pulse width modulator after above-mentioned sine wave signal and triangular signal progress addition process
Go out the superposed signal of sine wave and triangular wave, pulse width modulator carries out non-inverting input pulsewidth modulation letter to above-mentioned superposed signal
Number；
Step 3：Laser driver controls distributed feedback laser to detect gas to gas concentration according to pulse-width signal
The laser signal entrance port output wavelength scope of room is 1650~1656nm laser；
Step 4：The under test gas of concentration known is filled with gas concentration detection air chamber, gas concentration is detected in air chamber
The under test gas of concentration known absorbs to the light intensity of incident laser, and the laser signal of the gas concentration detection air chamber projects
The laser signal that mouth output light intensity weakens；
Step 5：The laser signal that the laser detector detects the output of air chamber laser signal exit wound of bullet to gas concentration enters
Row detection, and the laser induced electric signal of microvolt level is exported to processor；
Step 6：First signal generator exports the cosine wave equal with above-mentioned sine wave signal frequency to lock-in amplifier
Signal, lock-in amplifier carries out locking amplification to cosine wave signal forms demodulated reference signal, and lock-in amplifier is by demodulation reference
Signal is conveyed to processor, and triangular signal is conveyed to processor by secondary signal generator；
Step 7：Include the light intensity signal after the under test gas absorption of concentration known in the laser induced electric signal of microvolt level
Second harmonic, processor to above-mentioned second harmonic using demodulated reference signal and triangular signal carry out locking amplification demodulation,
It is the peak-to-peak value of second harmonic signal to obtain with the concentration dependent magnitude of voltage of the under test gas of concentration known, the magnitude of voltage, then
The concentration value of the magnitude of voltage and the under test gas of concentration known is normalized, obtains multigroup voltage signal and gas to be measured
The corresponding relation of bulk concentration, the corresponding relation of multigroup voltage signal and under test gas concentration is normalized to obtain above-mentioned
Second harmonic and the equation of under test gas concentration；
Step 8：The under test gas of concentration to be detected will be filled with gas concentration detection air chamber, then repeats step
1~step 3, then the under test gas of concentration to be detected in gas concentration detection air chamber the light intensity of incident laser is inhaled
Receive, the laser signal of the laser signal exit wound of bullet output light intensity decrease of the gas concentration detection air chamber；
Then step 5 and step 6 are repeated, then processor in the obtained laser induced electric signal of microvolt level to treating
The second harmonic of light intensity signal after the under test gas absorption of detectable concentration, utilizes the second harmonic that step 8 obtains and gas to be measured
The gas concentration of the under test gas of concentration to be detected is calculated in the equation of bulk concentration.
Gas concentration detection of the present invention based on optical fiber is completed by light in optical fiber, gas concentration detect air chamber,
Because transmission speed of the light in these media is fast, and the speed of opto-electronic conversion is also fast, so overall measuring speed is very fast.Light
The advantages of fibre detection, includes its essential safety, and photo measure interference is small, and the present invention is carried out using Wavelength modulation spectroscopy to laser
During modulation, the absorbing wavelength of gas can be accurately aimed at, hence it is evident that improve the inspection accuracy of gas concentration.
Brief description of the drawings
Fig. 1 is structured flowchart of the present invention；
Wherein, the 1-the first signal generator, 2-secondary signal generator, 3-adder, 4-pulse width modulator, 5-
Laser driver, 6-distributed feedback laser, 7-gas concentration detection air chamber, 8-laser detector, 9-locking amplification
Device, 10-processor.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail：
Gas concentration detection system of the invention based on Wavelength modulation spectroscopy, as shown in figure 1, it occurs including the first signal
Device 1, secondary signal generator 2, adder 3, pulse width modulator 4, laser driver 5, distributed feedback laser 6, gas are dense
Degree detection air chamber 7, laser detector 8, lock-in amplifier 9 and processor 10, the sine wave signal of first signal generator 1
Output end connects the first signal input part of adder 3, the triangular signal output end connection adder of secondary signal generator 2
3 secondary signal input, the signal input part of the signal output part connection pulse width modulator 4 of the adder 3, pulsewidth modulation
The signal input part of the signal output part connection laser driver 5 of device 4, the laser-driven signal output end of laser driver 5 connect
Connect the driving signal input of distributed feedback laser 6, the laser signal output end face of distributed feedback laser 6 is to gas
The laser signal entrance port of Concentration Testing air chamber 7, the signal input part of laser detector 8 detect air chamber 7 towards gas concentration
Laser signal exit wound of bullet, the signal input part of the laser induced signal output part connection processor 10 of laser detector 8, the first letter
The signal input part of the cosine wave signal output end connection lock-in amplifier 9 of number generator 1, the signal output of lock-in amplifier 9
The demodulated reference signal input of end connection processor 10, the triangular signal output end connection processing of secondary signal generator 2
The demodulated signal input of device 10.
In above-mentioned technical proposal, sine wave signal and the frequency of cosine wave signal that first signal generator 1 exports
It is 100 times of the frequency for the triangular signal that secondary signal generator 2 exports.Selection triangular wave is to be able to needed for scanning
Gas absorption spectrum line, and sine wave and cosine wave are to be demodulated use to modulated signal.Frequency between two kinds of signals
The relation for being designed as 100 times is because can well distinguish scanning signal and modulated signal on frequency domain, is detected
When obtain high accuracy of detection.
In above-mentioned technical proposal, sine wave signal and the frequency of cosine wave signal that first signal generator 1 exports
It is equal, and frequency range is 100Hz~100kHz；The frequency model for the triangular signal that the secondary signal generator 2 exports
Enclose for 1Hz~1kHz.
In above-mentioned technical proposal, the signal output part output sine wave of the adder 3 and the superposed signal of triangular wave are entered
Enter pulse width modulator 4, pulse width modulator 4 carries out non-inverting input pulse-width signal to above-mentioned superposed signal.Pulsewidth modulation
The measurement to gas can be completed according to different measurement frequency demands, measurement frequency is high, and pulse width modulation frequency needs higher.
In above-mentioned technical proposal, the distributed feedback laser 6 is used for the laser signal that air chamber 7 is detected to gas concentration
Entrance port output wavelength scope be 1650~1656nm (this scope is determined according to the absorption line of gas (methane),
The absorption line of methane is within this range) laser.
In above-mentioned technical proposal, the gas to be detected in the gas concentration detection air chamber 7 enters to the light intensity of incident laser
Row absorbs, the laser signal of the laser signal exit wound of bullet output light intensity decrease of the gas concentration detection air chamber 7.Weaken intensity
It is microvolt level after opto-electronic conversion calculates.
In above-mentioned technical proposal, the laser detector 8 is used for defeated to the gas concentration detection laser signal exit wound of bullet of air chamber 7
The laser signal gone out is detected, and exports the laser induced electric signal of microvolt level to processor 10.
In above-mentioned technical proposal, above-mentioned processor 10 is used to absorb the under test gas in the laser induced electric signal of microvolt level
The second harmonic of light intensity signal afterwards using demodulated reference signal and triangular signal carry out locking amplification demodulation, obtain with it is to be measured
The related magnitude of voltage of gas concentration, the magnitude of voltage are the peak-to-peak value of second harmonic signal, then with the under test gas of concentration known
Concentration value be normalized, obtain the corresponding relation of multigroup voltage signal and under test gas concentration, the magnitude of voltage be two
The peak-to-peak value of rd harmonic signal, the corresponding relation of multigroup voltage signal and under test gas concentration is normalized to obtain
State second harmonic equation corresponding with test gas concentration.
A kind of gas concentration detection method using said system, it comprises the following steps：
Step 1：First signal generator 1 is believed to the sine wave that the frequency of delivery scope of adder 3 is 100Hz~100kHz
Number, triangular signal of the secondary signal generator 2 to the frequency of delivery scope of adder 3 for 1Hz~1kHz；
Step 2：Adder 3 carries out above-mentioned sine wave signal and triangular signal after addition process to pulse width modulator 4
The superposed signal of sine wave and triangular wave is exported, pulse width modulator 4 carries out non-inverting input pulsewidth tune to above-mentioned superposed signal
Signal processed；
Step 3：Laser driver 5 controls distributed feedback laser 6 to be detected to gas concentration according to pulse-width signal
The laser signal entrance port output wavelength scope of air chamber 7 is 1650~1656nm laser；
Step 4：The under test gas of concentration known is filled with gas concentration detection air chamber 7, gas concentration is detected in air chamber 7
The under test gas of concentration known the light intensity of incident laser is absorbed, the laser signal of the gas concentration detection air chamber 7
The laser signal that exit wound of bullet output light intensity weakens；
Step 5：The laser detector 8 detects the laser signal of the laser signal exit wound of bullet of air chamber 7 output to gas concentration
Detected, and export the laser induced electric signal of microvolt level to processor 10；
Step 6：First signal generator 1 exports the cosine equal with above-mentioned sine wave signal frequency to lock-in amplifier 9
Ripple signal, lock-in amplifier 9 carry out locking amplification to cosine wave signal and form demodulated reference signal, and lock-in amplifier 9 will demodulate
Reference signal is conveyed to processor 10, and triangular signal is conveyed to processor 10 by secondary signal generator 2；
Step 7：Include the secondary humorous of the light intensity signal after the under test gas absorption of concentration known in the laser induced electric signal of microvolt level
Ripple, processor 10 carry out locking amplification demodulation (process to above-mentioned second harmonic using demodulated reference signal and triangular signal
Bibliography be：D’amico,A.,et al."Low-voltage low-power integrated analog lock-
in amplifier for gas sensor applications."Sensors and Actuators B:Chemical
144.2(2010):400-406.), it is secondary to obtain with the concentration dependent magnitude of voltage of the under test gas of concentration known, the magnitude of voltage
The peak-to-peak value of harmonic signal, then the concentration value of the magnitude of voltage and the under test gas of concentration known is normalized, obtained
To multigroup voltage signal and the corresponding relation of under test gas concentration, by multigroup voltage signal and the corresponding relation of under test gas concentration
It is normalized to obtain the equation of above-mentioned second harmonic and under test gas concentration；
Step 8：The under test gas of concentration to be detected will be filled with gas concentration detection air chamber 7, then repeats to walk
Rapid 1~step 3, then light intensity progress of the under test gas of the concentration to be detected in gas concentration detection air chamber 7 to incident laser
Absorb, the laser signal of the laser signal exit wound of bullet output light intensity decrease of the gas concentration detection air chamber 7；
Then step 5 and step 6 are repeated, then processor 10 is in the obtained laser induced electric signal of microvolt level
The under test gas of concentration to be detected absorb after light intensity signal second harmonic, using the second harmonic that step 8 obtains with it is to be measured
The gas concentration of the under test gas of concentration to be detected is calculated in the equation of gas concentration.
In above-mentioned technical proposal, under test gas selection is formaldehyde gas.
In above-mentioned technical proposal, the second harmonic and the equation of under test gas concentration are y=3.862x+0.03669, its
In, x represents the amplitude of second harmonic, and y represents under test gas concentration value.
In above-mentioned technical proposal, the second harmonic of light intensity signal is locked using demodulated reference signal and triangular signal
Amplifying the specific method demodulated is：
The second harmonic signal of absorption is extracted using lock-in amplifier (LIA).The signal and second harmonic line shape function
It is related.If locking output can be normalized the DC current signal for representing detector, the relation can be expressed as：
Wherein
Wherein, S2hSecond harmonic signal is represented, L represents the length of laser and gas adsorption effect, and N represents point in gas
Subnumber, relevant with pressure and temperature when surveyed concentration, measurement, S represents that under test gas (uses to the absorption line intensity of laser
Voigt line styles), it is relevant with temperature during measurement, Φ2hIn expression formula, ν represents gas absorption wavelength, νmRepresent wavelength modulation system
Number, sin (ωmT) wavelength modulation signal, ω are representedmT Sine Modulated frequencies, d are differential sign, and t represents the time of differential.
Peak-to-peak value with absorption maximum intensity second harmonic signal is expressed as：
Wherein, C represents under test gas concentration, and unit is [mol/mol], and L represents the length of laser and gas adsorption effect,
Unit is [m], and P represents to detect the pressure of air chamber, unit [P] during measurement, and T represents detection air chamber temperature during measurement, unit
[K], S represent that under test gas represents normalizing to the absorption line intensity (using voigt line styles) of laser, unit [cm/mol], φ (0)
Change under test gas to the maximum of the Absorption Line of laser, F (m) is second harmonic signal, can be expressed as：
Wherein φ2h+And φ2h-It is relative to the positive side of the baseline of second harmonic and the linear profile of the second harmonic of minus side
Amplitude, F (m) represent the concentration dependent magnitude of voltage of under test gas, and Δ ν represents the max line under test gas is to the Absorption Line of laser
It is wide.
The content that this specification is not described in detail belongs to prior art known to professional and technical personnel in the field.
Claims (10)
1. a kind of gas concentration detection system based on Wavelength modulation spectroscopy, it is characterised in that it includes the first signal generator
(1), secondary signal generator (2), adder (3), pulse width modulator (4), laser driver (5), distributed feedback laser
(6), gas concentration detection air chamber (7), laser detector (8), lock-in amplifier (9) and processor (10), first signal
First signal input part of the sine wave signal output end connection adder (3) of generator (1), secondary signal generator (2)
The secondary signal input of triangular signal output end connection adder (3), the signal output part connection arteries and veins of the adder (3)
The signal input part of wide modulator (4), the signal input of the signal output part connection laser driver (5) of pulse width modulator (4)
End, the driving signal input of the laser-driven signal output end connection distributed feedback laser (6) of laser driver (5),
The laser signal output end face of distributed feedback laser (6) detects the laser signal entrance port of air chamber (7) to gas concentration, swashs
The signal input part of photo-detector (8) detects the laser signal exit wound of bullet of air chamber (7), laser detector (8) towards gas concentration
Laser induced signal output part connection processor (10) signal input part, the cosine wave signal of the first signal generator (1)
The signal input part of output end connection lock-in amplifier (9), the signal output part connection processor (10) of lock-in amplifier (9)
Demodulated reference signal input, the demodulation letter of the triangular signal output end connection processor (10) of secondary signal generator (2)
Number input.
2. the gas concentration detection system according to claim 1 based on Wavelength modulation spectroscopy, it is characterised in that：Described
The sine wave signal of one signal generator (1) output and the frequency of cosine wave signal are secondary signal generator (2) output
100 times of the frequency of triangular signal.
3. the gas concentration detection system according to claim 1 based on Wavelength modulation spectroscopy, it is characterised in that：Described
One signal generator (1) output sine wave signal and cosine wave signal frequency it is equal, and frequency range be 100Hz~
100kHz；The frequency range of the triangular signal of secondary signal generator (2) output is 1Hz~1kHz.
4. the gas concentration detection system according to claim 1 based on Wavelength modulation spectroscopy, it is characterised in that：It is described to add
The signal output part output sine wave of musical instruments used in a Buddhist or Taoist mass (3) and the superposed signal of triangular wave enter pulse width modulator (4), pulse width modulator
(4) non-inverting input pulse-width signal is carried out to above-mentioned superposed signal.
5. the gas concentration detection system according to claim 1 based on Wavelength modulation spectroscopy, it is characterised in that：Described point
The laser signal entrance port output wavelength scope that cloth feedback laser (6) is used to detect air chamber (7) to gas concentration is 1650
~1656nm laser.
6. the gas concentration detection system according to claim 1 based on Wavelength modulation spectroscopy, it is characterised in that：The gas
Under test gas in bulk concentration detection air chamber (7) absorbs to the light intensity of incident laser, the gas concentration detection air chamber (7)
Laser signal exit wound of bullet output light intensity weaken laser signal.
7. the gas concentration detection system according to claim 1 based on Wavelength modulation spectroscopy, it is characterised in that：It is described to swash
Photo-detector (8) is used to detect the laser signal of gas concentration detection air chamber (7) laser signal exit wound of bullet output, and defeated
Go out the laser induced electric signal of microvolt level and give processor (10).
8. the gas concentration detection system according to claim 7 based on Wavelength modulation spectroscopy, it is characterised in that：Above-mentioned place
Manage the second harmonic utilization that device (10) is used for the light intensity signal after being absorbed to the under test gas in the laser induced electric signal of microvolt level
Demodulated reference signal and triangular signal carry out locking amplification demodulation, obtain and the concentration dependent magnitude of voltage of under test gas, the electricity
Pressure value is the peak-to-peak value of second harmonic signal, and then the concentration value with the under test gas of concentration known is normalized, and obtains
To multigroup voltage signal and the corresponding relation of under test gas concentration, the magnitude of voltage is the peak-to-peak value of second harmonic signal, will be multigroup
Voltage signal and the corresponding relation of under test gas concentration are normalized to obtain above-mentioned second harmonic and under test gas concentration
Corresponding equation.
9. a kind of gas concentration detection method using system described in claim 1, it is characterised in that it comprises the following steps：
Step 1：First signal generator (1) is believed to the sine wave that adder (3) frequency of delivery scope is 100Hz~100kHz
Number, triangular signal of the secondary signal generator (2) to adder (3) frequency of delivery scope for 1Hz~1kHz；
Step 2：Adder (3) carries out above-mentioned sine wave signal and triangular signal after addition process to pulse width modulator (4)
The superposed signal of sine wave and triangular wave is exported, pulse width modulator (4) carries out non-inverting input pulsewidth to above-mentioned superposed signal
Modulated signal；
Step 3：Laser driver (5) controls distributed feedback laser (6) to be detected to gas concentration according to pulse-width signal
The laser signal entrance port output wavelength scope of air chamber (7) is 1650~1656nm laser；
Step 4：The under test gas of concentration known is filled with gas concentration detection air chamber (7), gas concentration is detected in air chamber (7)
The under test gas of concentration known the light intensity of incident laser is absorbed, the laser letter of the gas concentration detection air chamber (7)
The laser signal that number exit wound of bullet output light intensity weakens；
Step 5：Laser signal of the laser detector (8) to gas concentration detection air chamber (7) laser signal exit wound of bullet output
Detected, and export the laser induced electric signal of microvolt level and give processor (10)；
Step 6：First signal generator (1) exports the cosine equal with above-mentioned sine wave signal frequency to lock-in amplifier (9)
Ripple signal, lock-in amplifier (9) carry out locking amplification to cosine wave signal and form demodulated reference signal, and lock-in amplifier (9) will
Demodulated reference signal is conveyed to processor (10), and secondary signal generator (2) is conveyed to triangular signal as demodulated signal
Processor (10)；
Step 7：Include two of the light intensity signal after the under test gas absorption of concentration known in the laser induced electric signal of microvolt level
Subharmonic, processor (10) carry out locking amplification demodulation to above-mentioned second harmonic using demodulated reference signal and triangular signal,
It is the peak-to-peak value of second harmonic signal to obtain with the concentration dependent magnitude of voltage of the under test gas of concentration known, the magnitude of voltage, then
The concentration value of the magnitude of voltage and the under test gas of concentration known is normalized, obtains multigroup voltage signal and gas to be measured
The corresponding relation of bulk concentration, the corresponding relation of multigroup voltage signal and under test gas concentration is normalized to obtain above-mentioned
Second harmonic and the equation of under test gas concentration；
Step 8：The interior under test gas for being filled with concentration to be detected of air chamber (7) will be detected in gas concentration, and then repeat step 1
~step 3, then the under test gas of the concentration to be detected in gas concentration detection air chamber (7) light intensity of incident laser is inhaled
Receive, the laser signal of the laser signal exit wound of bullet output light intensity decrease of the gas concentration detection air chamber (7)；
Then step 5 and step 6 are repeated, then processor (10) in the obtained laser induced electric signal of microvolt level to treating
The second harmonic of light intensity signal after the under test gas absorption of detectable concentration, utilizes the second harmonic that step 8 obtains and gas to be measured
The gas concentration of the under test gas of concentration to be detected is calculated in the equation of bulk concentration.
10. gas concentration detection method according to claim 9, it is characterised in that：The second harmonic and under test gas
The equation of concentration is y=3.862x+0.03669, wherein, x represents the amplitude of second harmonic, and y represents under test gas concentration value.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108872147A (en) * | 2018-06-22 | 2018-11-23 | 中国科学院长春光学精密机械与物理研究所 | A kind of generating device of laser and gas concentration detection apparatus based on TDLAS technology |
| CN110160976A (en) * | 2019-06-06 | 2019-08-23 | 中南大学 | Gas concentration detection method and system based on second harmonic interference envelope cancellation |
| CN113131811A (en) * | 2021-04-14 | 2021-07-16 | 中国船舶重工集团公司第七0三研究所 | FPGA-based stepping motor driving method |
| CN115494020A (en) * | 2022-09-30 | 2022-12-20 | 湖南五凌电力科技有限公司 | Trace gas detection method, device and system |
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| CN110160976A (en) * | 2019-06-06 | 2019-08-23 | 中南大学 | Gas concentration detection method and system based on second harmonic interference envelope cancellation |
| CN113131811A (en) * | 2021-04-14 | 2021-07-16 | 中国船舶重工集团公司第七0三研究所 | FPGA-based stepping motor driving method |
| CN115494020A (en) * | 2022-09-30 | 2022-12-20 | 湖南五凌电力科技有限公司 | Trace gas detection method, device and system |
| CN115494020B (en) * | 2022-09-30 | 2024-02-23 | 湖南五凌电力科技有限公司 | Trace gas detection method, device and system |
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