CN203534957U - Aerosol optical absorption coefficient detection device based on photoacoustic spectrum - Google Patents
Aerosol optical absorption coefficient detection device based on photoacoustic spectrum Download PDFInfo
- Publication number
- CN203534957U CN203534957U CN201320651001.3U CN201320651001U CN203534957U CN 203534957 U CN203534957 U CN 203534957U CN 201320651001 U CN201320651001 U CN 201320651001U CN 203534957 U CN203534957 U CN 203534957U
- Authority
- CN
- China
- Prior art keywords
- signal
- microphone
- amplifier
- absorption coefficient
- surge chamber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000010521 absorption reaction Methods 0.000 title claims abstract description 31
- 238000001514 detection method Methods 0.000 title claims abstract description 14
- 230000003287 optical effect Effects 0.000 title claims abstract description 11
- 239000000443 aerosol Substances 0.000 title abstract description 8
- 238000001834 photoacoustic spectrum Methods 0.000 title abstract description 3
- 238000004867 photoacoustic spectroscopy Methods 0.000 claims description 7
- 238000000034 method Methods 0.000 abstract description 6
- 230000005855 radiation Effects 0.000 abstract description 4
- 239000002245 particle Substances 0.000 abstract description 3
- 230000007613 environmental effect Effects 0.000 abstract description 2
- 210000004027 cell Anatomy 0.000 description 17
- 239000013078 crystal Substances 0.000 description 10
- 238000004611 spectroscopical analysis Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 230000003760 hair shine Effects 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- 238000010895 photoacoustic effect Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 210000003771 C cell Anatomy 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000000862 absorption spectrum Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000005427 atmospheric aerosol Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000013481 data capture Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000006552 photochemical reaction Methods 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Images
Abstract
The utility model discloses an aerosol optical absorption coefficient detection device based on a photoacoustic spectrum. Light emitted by a laser device passes through an electrooptical intensity modulator and a photoacoustic cell, and then is perpendicularly incident to a photoelectric detector; a signal wire of the photoelectric detector is connected with a computer provided with a data acquisition card; signal wires of a signal generator are connected with reference signal ends of the electrooptical intensity modulator and a phase lock amplifier respectively; a microphone is connected with an input end of a preamplifier; and an output end of the preamplifier is connected with the computer by the phase lock amplifier. Gas buffer chambers at the two ends of the photoacoustic cell can effectively buffer noise caused by an air flow; the laser intensity is modulated by electrooptical modulation, so that a signal to noise ratio of a system is increased; and an optical absorption coefficient of an aerosol particle at certain wavelength can be calculated by detecting an amplitude of a photoacoustic signal. The detection device overcomes the influence of scattered light by a direct absorption method, is more accurate in detection result, and provides an effective technical means for researching the influence of aerosol on atmospheric radiation and environmental climate.
Description
Technical field
The utility model relates to gasoloid absorption coefficient of light pick-up unit, is specifically related to a kind of gasoloid optical absorption coefficient pick-up unit based on optoacoustic spectroscopy.
Background technology
The haze weather of China produced in recent years scope and frequency increase day by day, have had a strong impact on the mankind's health with movable, and atmospheric aerosol is the principal element that gray haze sky produces, and is the important component part in environmental monitoring.Aerosol ion is the propagation in atmosphere to the inhalation effects radiation of light, causes visibility to reduce, and causes greenhouse effect, and the expection of Global climate change is had to vital effect.Particulate also causes the photochemical reaction between some particulates and between particulate and gas in atmosphere to the absorption of light, has produced much still immesurable impact.Therefore the device of studying gasoloid optical absorption coefficient has Great significance.
Photocaustic spectroscopy is based on optoacoustic effect, after gas absorption luminous energy, there is radiationless transition, produce heat energy and cause absorbing medium temperature to raise, if incident light is carried out in audio range to light intensity or wavelength-modulated, make the cyclical variation of medium temperature generation same frequency, thereby generation sound wave, can obtain gas concentration by surveying intensity of acoustic wave.With respect to conventional direct absorption spectrum, measure, the luminous energy of photocaustic spectroscopy direct-detection gas absorption, without background absorption, is a kind of method of absolute sense, and detection sensitivity is high.The application that photocaustic spectroscopy detects for gas is existing a lot, in recent years, this method is applied to the research to aerosol optical characteristics both at home and abroad.The NIST of the U.S. and domestic China Science & Technology University have carried out relevant research and application.
Utility model content
The purpose of this utility model is to provide a kind of gasoloid optical absorption coefficient pick-up unit based on optoacoustic spectroscopy, is on the optoacoustic architecture basics of typical cylindrical longitudinal resonance pattern, builds the pick-up unit of the gasoloid absorption coefficient of light.
The utility model solves the technical scheme that its technical matters adopts:
The utility model comprises laser instrument, electric light intensity modulator, photoacoustic cell, photodetector, microphone, prime amplifier, lock-in amplifier, computer and signal generator; The light that laser instrument sends passes through, after electric light intensity modulator, photoacoustic cell, to impinge perpendicularly on photodetector, and the signal wire of photodetector is connected with the computer that data collecting card is housed; The signal wire of signal generator is connected with the reference signal end of electric light intensity modulator and lock-in amplifier respectively; The microphone signal line being contained in photoacoustic cell is connected with the input end of prime amplifier, and the output terminal of prime amplifier is connected with the detection signal end of lock-in amplifier, and the signal output part of lock-in amplifier is connected with computer.
Described photoacoustic cell is cylindrical cavity, the two ends of photoacoustic cell are the symmetrical surge chamber that has same size respectively, on the cylindrical cavity of a surge chamber, have air intake opening, on the cylindrical cavity of another surge chamber, have gas outlet, two surge chambers are communicated with resonant cavity, the cylindrical cavity side at resonant cavity middle part has microphone mount pad, microphone is arranged in microphone mount pad, microphone sensitive face stretches in resonant cavity, the openend of two surge chambers is equipped with respectively cover plate, two cover plates is windowing respectively, two windows that are positioned at surge chamber one side post respectively piezoid, two windows, the center line of two surge chambers and resonant cavity is positioned on same axis.
The length L of described resonant cavity
clength L with surge chamber
dpass be L
c=2L
d; The pass of the diameter R of surge chamber and the diameter r of resonant cavity is R>4r.
The beneficial effect the utlity model has is:
The utility model is on the optoacoustic architecture basics of typical cylindrical longitudinal resonance pattern, builds the pick-up unit of the gasoloid absorption coefficient of light.The gas buffer chamber noise that effectively buffer gas flow brings at photoacoustic cell two ends.Adopt electrooptical modulation to modulate laser intensity, the noise of having avoided traditional mechanical chopper to bring, has improved the signal to noise ratio (S/N ratio) of system.By detecting the amplitude of photoacoustic signal, can calculate the absorption coefficient of light of aerosol particle under certain wavelength.The utility model is the detection for the gasoloid absorption coefficient of light by photocaustic spectroscopy, has overcome the impact of direct absorption process scattered light, and testing result is more accurate, for research gasoloid provides effective technological means to the impact of atmosphere radiation and amblent air temperature.The utlity model has that high, the detectable limit of measuring accuracy is little, light belt is wide, the advantage of real-time online measuring.
Accompanying drawing explanation
Fig. 1 is structured flowchart of the present utility model.
Fig. 2 is the structural representation of photoacoustic cell.
Fig. 3 is that electric light intensity modulator forms schematic diagram.
In figure: 1, laser instrument, 2, electric light intensity modulator, 3, photoacoustic cell, 4, photodetector, 5, microphone, 6, prime amplifier, 7, lock-in amplifier, 8, computer, 9, signal generator, 10, piezoid, 11, surge chamber, 12, resonant cavity, 13, microphone mount pad, 14, air intake opening, 15, gas outlet, 16, electro-optic crystal, 17, polarizer, 18, high-voltage amplifier.
Embodiment
Below in conjunction with the drawings and specific embodiments, the utility model is described further.
Optoacoustic spectroscopy is based on optoacoustic effect, after gas absorption luminous energy, there is radiationless transition, produce heat energy and cause absorbing medium temperature to raise, if incident light is carried out in audio range to light intensity or wavelength-modulated, make the cyclical variation of medium temperature generation same frequency, thereby produce sound wave.By surveying intensity of acoustic wave, can obtain concentration or the absorption coefficient of gas (or gasoloid).
By photoacoustic signal mechanism of production and sound field distribution theory, the expression formula that can obtain photoacoustic signal is
S
PA＝S
mC
cellαPc （1）
S
pA---photoacoustic spectrum (V);
S
m---sensitivity of microphone (V/Pa);
C
cell---pond constant (PacmW
-1);
α---gasoloid absorption coefficient (cm
-1);
The peak-to-peak value of P---luminous power (W);
C---tested aerocolloidal concentration.
By formula (1), can derive aerocolloidal absorption coefficient:
Aerocolloidal concentration c is known, the sensitivity S of microphone 5
mutilize B & K acoustic calibration platform to demarcate.The peak-to-peak value P of luminous power calculates by gathering the voltage magnitude of photodetector 4.Pond constant C
cellthe ability that to have weighed optoacoustic system be acoustic energy by the light energy conversion of gas absorption, can demarcate the detection of the calibrating gas of concentration known by this device.Photoacoustic signal S
pAneed this measurement device to obtain.
Due to photoacoustic signal S
pAvery faint with respect to noise, be difficult to direct detection and arrive, therefore need lock-in amplifier that photoacoustic signal is restored.The principle of lock-in amplifier based on cross-correlation detection, utilize noise signal and periodic signal not to have the feature of correlativity, by calculating signal to be checked and reference signal, in the method for the related operation at zero point, suppress noise and extract the periodic signal of characteristic frequency (being the frequency of reference signal), and the signal of other frequencies is suppressed, get off.
Being designed and sized to of photoacoustic cell: L
c=100mm, L
d=50mm, r=6mm, R=30mm.In theory, single order longitudinal resonance frequency
v is the velocity of sound (340m/s).For the photoacoustic cell example providing above, theoretical resonant frequency f=1700Hz, owing to being subject to the impact of processing conditions and microphone mount pad 13 and surge chamber 11, the actual value of experiment measuring is 1650Hz.The set of frequency of the modulation signal of signal generator and reference signal fr is 1650Hz.
As shown in Figure 1, the utility model comprises laser instrument 1, electric light intensity modulator 2, photoacoustic cell 3, photodetector 4, microphone 5, prime amplifier 6, lock-in amplifier 7, computer 8 and signal generator 9.The light that laser instrument 1 sends passes through, after electric light intensity modulator 2, photoacoustic cell 3, to impinge perpendicularly on photodetector 4, and the signal wire of photodetector 4 is connected with the computer 8 that data collecting card is housed; The signal wire of signal generator 9 is connected with the reference signal end of electric light intensity modulator 2 and lock-in amplifier 7 respectively; Microphone 5 signal wires that are contained in photoacoustic cell 3 are connected with the input end of prime amplifier 6, and the output terminal of prime amplifier 6 is connected with the detection signal end of lock-in amplifier 7, and the signal output part of lock-in amplifier 7 is connected with computer 8.
This device laser instrument is the solid state laser of 532nm, and model is MLL-FN-532, and power is 200mW.Photodetector model is PDA100A, and microphone is selected EK-23111 silicon micro-microphone, and prime amplifier model is SR550, and lock-in amplifier is SR830, and signal generator is DS360, and data collecting card adopts 4472 of NI.Electric light intensity modulator is to build on the basis of electro-optic crystal 16, and specific implementation as shown in Figure 3.In figure, electro-optic crystal 16 models are EO-AM-NR-C4, and polarizer 17 adopts glan-thompson polarizers, and high-voltage amplifier 18 models are HVA200.
As shown in Figure 3, electro-optic crystal is under the effect of extra electric field, and phase delay becomes with the size of extra electric field, causes the variation of polarization state thereupon, thereby the amplitude of the emergent light of polarizer is modulated.Because the light of laser instrument used approaches linearly polarized light, be directly incident on electro-optic crystal 16 and modulate, if natural light needs first to rise partially by polarizer, reenter and be mapped to electro-optic crystal and modulate.Signal generator 9 produces modulation signal, after high-voltage amplifier 18 amplifies, to electro-optic crystal 16 input modulation voltages, incident light is through the modulation of electro-optic crystal 16, after polarizer 17, emergent light intensity is cycle variation, and the change frequency of light intensity is consistent with the frequency of modulation signal, thereby realizes the intensity modulated to laser.
As shown in Figure 2, described photoacoustic cell 3 is cylindrical cavity, the two ends of photoacoustic cell 3 are the symmetrical surge chamber that has same size respectively, on the cylindrical cavity of a surge chamber, have air intake opening 14, on the cylindrical cavity of another surge chamber, have gas outlet 15, two surge chambers are communicated with resonant cavity 12, the cylindrical cavity side at resonant cavity 12 middle parts has microphone mount pad 13, microphone 5 is arranged in microphone mount pad 13, microphone 5 sensitive faces stretch in resonant cavity 12, the sensitive face of microphone flushes with resonant cavity sidewall as far as possible, the openend of two surge chambers is equipped with respectively cover plate, cover plate with the openend of two surge chambers for being threaded, or connect with screw, two cover plates is windowing respectively, two windows that are positioned at surge chamber one side post respectively piezoid 10, two windows, the center line of two surge chambers and resonant cavity 12 is positioned on same axis.
The length L of described resonant cavity 12
clength L with surge chamber 11
dpass be L
c=2L
d; The pass of the diameter R of surge chamber and the diameter r of resonant cavity is R>4r.
Detecting step of the present utility model is:
Step 1), according to Fig. 1, is adjusted light path: the light that laser instrument 1 sends, after electro-optic crystal 16, polarizer 17, shines photoacoustic cell 3.Light path, by the piezoid 10 of photoacoustic cell 3, shines photodetector 4.The signal wire of luminous power is connected with the computer 8 that data collecting card is housed.
Step 2) according to Fig. 1, carry out electrical signal connection: the signal wire of signal generator 9 is connected with the input end of high-voltage amplifier 18 and the reference signal end of lock-in amplifier 7 respectively, the output terminal of high-voltage amplifier 18 is connected with the signal wire of electro-optic crystal 16.Modulation signal fr(square wave or sine wave that signal generator produces) on the one hand to electric light intensity modulator output modulation signal, on the other hand as be input to lock-in amplifier 7 with reference to signal.The signal wire of microphone 5 is connected with prime amplifier 6 signal input parts, and the signal output part of prime amplifier 6 is connected with the signal input part of lock-in amplifier 7.Lock-in amplifier 7 output lines are connected with the data collecting card of computer 8.The frequency of the modulation signal of signal generator 9 (reference signal) fr is identical with the first order resonance frequency of resonant cavity, be set to 1650Hz.
The gasoloid of step 3) concentration known c is passed through by air intake opening 14, by gas outlet 15, is extracted out.Open the software of the exploitation of labview on computer 8, the data that reading out data capture card collects, extract the amplitude S of photoacoustic signal
pA, the peak-to-peak value P of luminous power, in conjunction with known pond constant C
cellwith sensitivity of microphone S
m, according to formula (2), calculate aerocolloidal absorption coefficient.After pending data is stable, record the now value of α, being concentration is the aerocolloidal absorption coefficient to the light of 532nm of c.
The utility model is on the optoacoustic architecture basics of typical cylindrical longitudinal resonance pattern, builds the pick-up unit of the gasoloid absorption coefficient of light.By detecting the amplitude of photoacoustic signal, can calculate the absorption coefficient of light of aerosol particle under certain wavelength.The utility model is the detection for the gasoloid absorption coefficient of light by photocaustic spectroscopy, has overcome the impact of direct absorption process scattered light, and testing result is more accurate, for research gasoloid provides effective technological means to the impact of atmosphere radiation and amblent air temperature.
Claims (3)
1. the gasoloid optical absorption coefficient pick-up unit based on optoacoustic spectroscopy, is characterized in that: comprise laser instrument (1), electric light intensity modulator (2), photoacoustic cell (3), photodetector (4), microphone (5), prime amplifier (6), lock-in amplifier (7), computer (8) and signal generator (9); The light that laser instrument (1) sends passes through, after electric light intensity modulator (2), photoacoustic cell (3), to impinge perpendicularly on photodetector (4), and the signal wire of photodetector (4) is connected with the computer (8) that data collecting card is housed; The signal wire of signal generator (9) is connected with the reference signal end of lock-in amplifier (7) with electric light intensity modulator (2) respectively; Microphone (5) signal wire being contained in photoacoustic cell (3) is connected with the input end of prime amplifier (6), the output terminal of prime amplifier (6) is connected with the detection signal end of lock-in amplifier (7), and the signal output part of lock-in amplifier (7) is connected with computer (8).
2. a kind of gasoloid optical absorption coefficient pick-up unit based on optoacoustic spectroscopy according to claim 1, it is characterized in that: described photoacoustic cell (3) is cylindrical cavity, the two ends of photoacoustic cell (3) are the symmetrical surge chamber that has same size respectively, on the cylindrical cavity of a surge chamber, have air intake opening (14), on the cylindrical cavity of another surge chamber, have gas outlet (15), two resonant cavities for surge chamber (12) are communicated with, the cylindrical cavity side at resonant cavity (12) middle part has microphone mount pad (13), microphone (5) is arranged in microphone mount pad (13), microphone (5) sensitive face stretches in resonant cavity (12), the openend of two surge chambers is equipped with respectively cover plate, two cover plates is windowing respectively, two windows that are positioned at surge chamber one side post respectively piezoid (10), two windows, the center line of two surge chambers and resonant cavity (12) is positioned on same axis.
3. a kind of gasoloid optical absorption coefficient pick-up unit based on optoacoustic spectroscopy according to claim 2, is characterized in that: the length L of described resonant cavity (12)
clength L with surge chamber
dpass be L
c=2L
d; The pass of the diameter R of surge chamber and the diameter r of resonant cavity is R>4r.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320651001.3U CN203534957U (en) | 2013-10-21 | 2013-10-21 | Aerosol optical absorption coefficient detection device based on photoacoustic spectrum |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320651001.3U CN203534957U (en) | 2013-10-21 | 2013-10-21 | Aerosol optical absorption coefficient detection device based on photoacoustic spectrum |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203534957U true CN203534957U (en) | 2014-04-09 |
Family
ID=50421152
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320651001.3U Expired - Lifetime CN203534957U (en) | 2013-10-21 | 2013-10-21 | Aerosol optical absorption coefficient detection device based on photoacoustic spectrum |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203534957U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103604752A (en) * | 2013-10-21 | 2014-02-26 | 浙江省计量科学研究院 | Photoacoustic spectrometry based detection device for optical absorption coefficient of aerosol |
| CN104237154A (en) * | 2014-08-29 | 2014-12-24 | 浙江省计量科学研究院 | Device for detecting methane and carbon dioxide in atmospheric greenhouse gas based on photoacoustic spectrum technology |
| CN104280340A (en) * | 2014-10-28 | 2015-01-14 | 山西大学 | Device and method for detecting gas based on LED light source and by adopting electrical modulation phase elimination way |
| CN104792703A (en) * | 2015-03-17 | 2015-07-22 | 浙江省计量科学研究院 | Laser multiple reflection photoacoustic spectroscopy technology-based aerosol optical absorption coefficient detection apparatus |
| CN109724919A (en) * | 2017-10-27 | 2019-05-07 | 曲阜师范大学 | Multicomponent Pollution Gas detection light acousto-optic spectral apparatus based on solar tracking |
-
2013
- 2013-10-21 CN CN201320651001.3U patent/CN203534957U/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103604752A (en) * | 2013-10-21 | 2014-02-26 | 浙江省计量科学研究院 | Photoacoustic spectrometry based detection device for optical absorption coefficient of aerosol |
| CN104237154A (en) * | 2014-08-29 | 2014-12-24 | 浙江省计量科学研究院 | Device for detecting methane and carbon dioxide in atmospheric greenhouse gas based on photoacoustic spectrum technology |
| CN104280340A (en) * | 2014-10-28 | 2015-01-14 | 山西大学 | Device and method for detecting gas based on LED light source and by adopting electrical modulation phase elimination way |
| CN104280340B (en) * | 2014-10-28 | 2016-08-03 | 山西大学 | The gas detection apparatus based on LED light source and using electricity modulation phase resolving therapy and method |
| CN104792703A (en) * | 2015-03-17 | 2015-07-22 | 浙江省计量科学研究院 | Laser multiple reflection photoacoustic spectroscopy technology-based aerosol optical absorption coefficient detection apparatus |
| CN104792703B (en) * | 2015-03-17 | 2017-05-31 | 浙江省计量科学研究院 | Detection device for optical absorption coefficient of aerosol based on laser multiple reflections optoacoustic spectroscopy |
| CN109724919A (en) * | 2017-10-27 | 2019-05-07 | 曲阜师范大学 | Multicomponent Pollution Gas detection light acousto-optic spectral apparatus based on solar tracking |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103604752A (en) | Photoacoustic spectrometry based detection device for optical absorption coefficient of aerosol | |
| CN203534957U (en) | Aerosol optical absorption coefficient detection device based on photoacoustic spectrum | |
| CN103983544B (en) | Hyperchannel aerosol scattering absorption measuring apparatus | |
| CN103604774B (en) | The method and apparatus improving laser gas analysis sensitivity based on non-linear tuning | |
| CN202974860U (en) | High-precision infrared gas detection module | |
| CN109991189B (en) | Fixed point wavelength modulation gas concentration measuring device based on wave number drift correction and measuring method thereof | |
| CN103344614B (en) | A kind of atmospheric transmissivity at high precision measurement mechanism and measuring method | |
| CN104251842A (en) | Method for realization of online calibration of photoacoustic spectroscopy system pool constants by use of oxygen in atmosphere | |
| CN106124410A (en) | Single photoacoustic cell measures the new method of aerosol multi-wavelength absorptance simultaneously | |
| CN104792703B (en) | Detection device for optical absorption coefficient of aerosol based on laser multiple reflections optoacoustic spectroscopy | |
| CN104251819A (en) | Photoacoustic spectrometry gas detection apparatus based on infrared light source | |
| CN103175759A (en) | Method for acquiring complex refractive index of urban aerosol on basis of various ground-based remote sensing technologies | |
| CN104020114A (en) | Method for analyzing trace concentration of ammonia gas | |
| CN104697933B (en) | Triple channel acoustic resonant cavity optoacoustic spectroscopy sensing device | |
| CN103884672A (en) | SF6 gas decomposed product detection device and method based on photoacoustic spectrometry technology | |
| CN105466854A (en) | Active air-chamber structure and photoacoustic spectrometry gas sensing system | |
| CN102879835A (en) | Method for measuring laser rainfall weather phenomenon and laser rainfall weather phenomenon instrument | |
| CN205607812U (en) | Particle size detection device | |
| CN209372684U (en) | A kind of tunable laser light acousto-optic spectrum trace gas detection experiment device for teaching | |
| CN107884344A (en) | A kind of optoacoustic spectroscopy gas sensing system of the active air chamber based on semiconductor laser | |
| CN204008440U (en) | The signal processing apparatus and the gas detecting system thereof that detect for difference gas | |
| CN201622228U (en) | Dynamic polarized light scattered grain measuring device | |
| CN107991240B (en) | Multifunctional photoelectric detector based on quartz tuning fork resonance principle | |
| CN102980941B (en) | A kind of ultrasonic gas relative humidity detection method and device utilizing sonic velocity change | |
| CN111337453A (en) | Multipoint gas concentration detection method and detection device for eliminating dynamic loss influence |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20140409 |
|
| CX01 | Expiry of patent term |