CN112858184B - Gas measuring device and method based on piezoelectric material - Google Patents
Gas measuring device and method based on piezoelectric material Download PDFInfo
- Publication number
- CN112858184B CN112858184B CN202110127194.1A CN202110127194A CN112858184B CN 112858184 B CN112858184 B CN 112858184B CN 202110127194 A CN202110127194 A CN 202110127194A CN 112858184 B CN112858184 B CN 112858184B
- Authority
- CN
- China
- Prior art keywords
- photoacoustic
- light source
- cavity
- signal
- piezoelectric
- 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.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
- G01N2021/1704—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids in gases
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
The invention discloses a piezoelectric material-based gas measuring device and method. The piezoelectric photoacoustic wave collecting cavity of the core device of the device is made of piezoelectric materials, so that the high-efficiency collection and detection of photoacoustic wave signals can be realized; the detection method is that light beams output by the excitation light source interact with target gas in the photoinduced acoustic wave collection cavity to generate photoacoustic signals, the photoacoustic signals cause the volume of the photoinduced acoustic wave collection cavity to deform periodically, electric signals are generated based on the piezoelectric effect, and the signals are processed by the signal processing assembly to obtain gas concentration information. The photoinduced sound wave collecting cavity avoids the use of a broadband microphone, reduces the volume of the photoacoustic cell, reduces the preparation difficulty and cost of the photoacoustic cell, improves the detection efficiency of photoacoustic signals and the immunity of the device to environmental noise, and realizes high-precision detection of target gas.
Description
Technical Field
The invention relates to a gas sensing technology, in particular to a gas measuring device and method based on piezoelectric materials.
Background
The detection of gas components and types is of great significance, and particularly in the current society with rapid development of science and technology, the trace gas detection technology plays an increasingly important role in the fields of environment, industry, aerospace, medical technology and the like. In recent years, as one of indirect absorption spectroscopy, photoacoustic spectroscopy has received great attention due to its characteristics of zero background, good selectivity, no wavelength selectivity, positive correlation between detection sensitivity and excitation light power, and the like, and has been successfully applied in many fields.
The principle of judging the gas type and measuring the gas concentration by adopting the photoacoustic spectroscopy method is as follows: the difference of self energy level structures of gas molecules enables any gas molecule to absorb laser energy of certain specific wave bands, the absorbed laser energy enables the gas molecules originally in a ground state to jump to an excited state, but due to the instability of a high-energy level excited state, the molecules jumping to the excited state can return to the ground state again through collision relaxation, and meanwhile, the absorbed light energy is converted into kinetic energy of the molecules according to the law of energy conservation, so that the temperature of the gas molecules interacting with the laser in the gas chamber is increased. When the laser is modulated at a certain frequency, the local temperature will periodically rise and fall, so as to generate an acoustic wave signal consistent with the modulation frequency. After the acoustic wave signal is converted into a current signal or a voltage signal by using the acoustic-electric transducer, the concentration and other related information of the target gas can be obtained by analyzing the electrical signal.
In a detection system based on a traditional photoacoustic spectrum detection technology, core components comprise a gas photoacoustic cell and a broadband high-sensitivity microphone, wherein the gas photoacoustic cell is used for loading target gas and restraining a photoinduced acoustic wave signal, and in general, each geometric parameter of the gas photoacoustic cell is calculated in detail to control the resonant frequency and the quality factor of the gas photoacoustic cell and ensure that the acoustic wave signal in the photoacoustic cell can form resonance in a cavity to enhance the detection efficiency of the photoacoustic signal; a high-sensitivity microphone is generally mounted at a specific portion of the photoacoustic cell, and for a resonance type photoacoustic cell which is most widely used at present, a microphone for collecting a photoacoustic signal is generally mounted at a geometric center portion of a side wall of the photoacoustic cell, because a sound wave of the resonance type photoacoustic cell resonates in an acoustic cavity and a position where the intensity of the resonance sound wave is maximum is located, as shown in fig. 1. The microphone is mounted to prevent the background noise such as gas flow noise and window thermal noise from affecting the microphone as much as possible. The main problems faced by the traditional photoacoustic spectroscopy technology using a photoacoustic cell and a high-sensitivity microphone in the practical application process are that the traditional photoacoustic cell is large in size, and the high-sensitivity microphone is wide in frequency response curve and is easily interfered by environmental noise. In addition, the uneven part of the inner wall of the photoacoustic cavity will cause the loss of the photoacoustic cavity to increase, i.e. the quality factor of the photoacoustic cell is reduced, and finally the detection sensitivity of the photoacoustic cell is reduced. Therefore, the inner wall of the acoustic cavity of the photoacoustic cell must be finely ground in the processing process, and the operation is time-consuming and greatly increases the processing cost of the photoacoustic cell.
The quartz enhanced photoacoustic spectroscopy technology well solves the problems faced by the conventional photoacoustic spectroscopy technology. Unlike the conventional photoacoustic spectroscopy technology using a gas photoacoustic cell and a high-sensitivity microphone, the quartz-enhanced photoacoustic spectroscopy technology uses a quartz material with piezoelectric properties to realize the detection of photoacoustic signals, and is first proposed in 2002 by the university of rice in the united states. In the quartz enhanced photoacoustic spectroscopy technology, an excitation light source passes through two vibrating arms of a tuning fork quartz crystal oscillator without collision, a photoinduced photoacoustic signal pushes the vibrating arms of the quartz tuning fork to vibrate, and then the tuning fork quartz crystal oscillator converts mechanical vibration energy into electric signals through the piezoelectric effect, and the electric signals are proportional to the concentration of the detected gas. The quartz enhanced photoacoustic spectrometry technology successfully applies the piezoelectric material to the field of trace gas detection, but the technology has certain difficulty in popularization and application. First, the volume of the tuning fork quartz crystal oscillator is small, which results in a gas volume less than 1mm that effectively reacts with the excitation light source3In addition, the piezoelectric coefficient of quartz material is not high, so the detection sensitivity of the technology is inferior to that of the traditional photoacoustic spectroscopy technology. In order to solve the above problems, researchers usually add a set of micro acoustic resonant cavities at two ends of a quartz tuning fork symmetrically, and enhance photoacoustic signals through the resonance effect of sound waves in the resonant cavities, thereby improving detection sensitivity. However, the operation is such that the requirement of the quartz enhanced photoacoustic spectroscopy technology on the assembly precision is very high, for example, the distance between the side wall of the micro-acoustic resonant cavity and the side surface of the quartz tuning fork needs to be strictly controlled within 50-100 microns so as to ensure the efficient coupling of the micro-acoustic resonant cavity and the quartz tuning fork. In addition, the requirement of the quartz enhanced photoacoustic spectroscopy technology on an excitation light source is also very strict, and the excitation light source with poor light beam quality or high power cannot be directly used for the quartz enhanced photoacoustic spectroscopy technology. In addition to the above problems, the collimation of the optical path is also a big problem in the practical application of the quartz enhanced photoacoustic spectroscopy technology, because the excitation light source of the photoacoustic signal must pass through the gap between the two vibrating arms of the tuning fork quartz crystal oscillator (the width is about 0.3mm) and the micro-acoustic resonant cavity (the diameter is about 0.6mm,total length of about 10 mm).
How to overcome the above-mentioned problem that traditional photoacoustic spectroscopy technique and novel photoacoustic spectroscopy technique exist is the key with photoacoustic spectroscopy technique wide application in trace gas detection area, and the gaseous photoacoustic sensor who overcomes above-mentioned key problem will have very wide application prospect.
Disclosure of Invention
The invention provides a gas measuring device and method based on piezoelectric materials, and aims to solve the problems that the traditional photoacoustic spectroscopy technology is large in size, easy to be interfered by environmental noise, difficult to polish the inner wall of a photoacoustic cavity, high in cost and the like, and the quartz enhanced photoacoustic spectroscopy technology is high in requirements for the quality of light beams of an excitation light source and poor in detection sensitivity and the like.
In order to achieve the purpose, the invention adopts the following technical scheme:
1. a gas measuring device based on piezoelectric materials comprises a piezoelectric photoacoustic cavity component, a sound insulation supporting component, an excitation light source part and a signal processing component, wherein the piezoelectric photoacoustic cavity component is made of piezoelectric materials; the piezoelectric photoacoustic cavity assembly comprises a photoinduced acoustic wave collecting cavity made of piezoelectric materials and two collecting electrodes which are arranged on the inner wall and the outer wall of the photoinduced acoustic wave collecting cavity and used for collecting piezoelectric charges; the sound insulation support assembly is provided with an air inlet, an air outlet, an excitation light source incident window, an excitation light source emergent window, a photoacoustic cavity support assembly and two conductive electrodes, the air inlet and the air outlet are respectively positioned at the oblique symmetrical positions of the sound insulation support assembly, the excitation light source incident window and the exciting light source emergent window are respectively positioned on the two end side surfaces of the hollow part of the photoacoustic wave collection cavity, the photoacoustic cavity support assembly fixes the photoacoustic wave collection cavity on the inner wall of the sound insulation support assembly, and the entrance and the exit of the excitation light source incident window, the excitation light source emergent window and the photoacoustic wave collection cavity are positioned on the same straight line; the two conductive electrodes are arranged on the side wall of the sound insulation supporting component and are mutually insulated from the sound insulation supporting component, one ends of the two conductive electrodes positioned on the inner side of the sound insulation supporting component are respectively connected with the two current collecting electrodes on the photoinduced sound wave collecting cavity, and one ends of the outer sides of the two conductive electrodes are respectively connected with the input end of the signal preprocessing module; the excitation light source part comprises an excitation light source and an excitation light source drive, the excitation light source drive comprises a current drive module and a laser temperature control module, and the outputs of the current drive module and the laser temperature control module are both connected with the excitation light source; the signal processing assembly comprises a signal generator, a signal preprocessing circuit module, a phase-locked amplifying circuit module, a single chip microcomputer or a microcomputer, the signal output end of the signal generator is connected with the current driving module, the synchronous signal output end of the signal generator is connected with the synchronous signal input end of the phase-locked amplifying circuit module, the output of the signal preprocessing circuit module is connected with the signal input end of the phase-locked amplifying circuit module, and the output of the phase-locked amplifying circuit module is connected with the single chip microcomputer or the microcomputer.
Further, the piezoelectric material is a flexible or non-flexible material having piezoelectric properties. To ensure that the photoacoustic signal detection is effectively achieved based on a photoacoustic wave collection cavity made of a piezoelectric material having a piezoelectric coefficient greater than 2 x 10-12C/N。
Furthermore, the core device of the invention is a photoinduced sound wave collecting cavity prepared by adopting a piezoelectric material. The method for preparing the photoacoustic wave collection cavity from the piezoelectric material is different according to the difference of Young modulus and yield strength of the piezoelectric material, and is mainly divided into the following two types: for soft and flexible piezoelectric materials, including but not limited to polyvinylidene fluoride materials and hybrid perovskite flexible piezoelectric materials, the following method is usually adopted to make the photoacoustic wave collection cavity: the method comprises the steps of curling a rectangular flexible piezoelectric material into a cylindrical shape, enabling the inner surface and the outer surface of the flexible piezoelectric material to have an overlapping area, bonding the overlapping area by adopting insulating glue to prepare a photoinduced sound wave collecting cavity, and bonding current collecting electrodes on the inner surface and the outer surface of two ends of the photoinduced sound wave collecting cavity by adopting conductive glue; the overlapping length of the overlapping area is controlled to be between 4% and 7% of the circumferential length of the cylinder; the non-flexible piezoelectric materials, including but not limited to lead zirconate titanate, ferroelectric crystals and other various polymer piezoelectric materials, are usually prepared by directly adopting a stacking method or a co-sintering method according to the geometric dimension of the photo-induced acoustic wave collection cavity calculated by theory. The inner surface and the outer surface of the photoinduced sound wave collecting cavity prepared by the method also need to be respectively bonded with a collecting electrode by adopting conductive glue for collecting and conducting piezoelectric charges outwards. The piezoelectric material stacking method or the co-sintering method is a common standard production process in the field of piezoelectric material production and processing, and the process is mature, simple, convenient and efficient.
When the device is used, an excitation light source of the photoacoustic signal passes through the center of the photoacoustic wave collecting cavity made of the piezoelectric material without collision. The target gas interacts with the excitation light source to generate a photoacoustic signal, and the frequency of the photoacoustic signal is the same as the modulation frequency of the excitation light source. The photoacoustic wave collecting cavity generates periodic expansion and contraction under the action of sound pressure, and the frequency of the expansion and contraction is the same as that of the photoacoustic signal. The photoacoustic wave collection cavity is now equivalently subjected to a periodic mechanical stress in its radial direction. Further, the periodic mechanical stress is converted into piezoelectric charges based on the piezoelectric characteristics of the piezoelectric material, and the positive and negative charges of the piezoelectric charges are distributed on two surfaces of the piezoelectric material respectively. The two electrodes for collecting the piezoelectric charges are respectively connected with the inner surface and the outer surface of the photoacoustic wave collecting cavity, so that the piezoelectric charges generated by the photoacoustic wave collecting cavity are collected. Different from the traditional resonance type photoacoustic cell which can only detect and collect the strength information of the photoinduced sound wave at the installation position of the microphone, the photoinduced sound wave collecting cavity prepared by adopting a piezoelectric material can simultaneously collect the strength information of the photoinduced sound wave at all the positions in the whole photoinduced sound wave collecting cavity, and converts the strength signal of the photoinduced sound wave into an electric signal by depending on the piezoelectric property of the photoinduced sound wave collecting cavity and outputs the electric signal to the outside. Therefore, the collection capacity of the photo-induced acoustic wave collection cavity prepared by the piezoelectric material to the same photo-induced acoustic wave signal is far higher than that of a resonance type photoacoustic cell with a traditional structure.
Furthermore, the photoacoustic cavity supporting assembly is an annular outer support matched with the structure of the photoinduced acoustic wave collecting cavity, and the annular outer support is composed of two semicircular arc-shaped supports. The inner side of the annular outer support ring is in close contact with the outer surface of the light induced sound wave collecting cavity, and the outer side of the annular outer support ring is fixed on the inner wall of the sound insulation supporting component, so that the positioning and fixing effects of the annular outer support ring on the light induced sound wave collecting cavity are realized. Ensure that the rigid connection of the photoinduced sound wave collecting cavity and the sound insulation supporting component does not shake.
Furthermore, in order to fully collect the piezoelectric charges distributed on the surface of the photo-induced acoustic wave collection cavity, conductive films can be respectively grown or coated on the inner surface and the outer surface of the photo-induced acoustic wave collection cavity, the conductive films on the inner surface and the outer surface of the photo-induced acoustic wave collection cavity are ensured to be mutually insulated, and the conductive films are in good conductive contact with the collecting electrodes on the same surface.
Still further, the excitation light source section may further include a beam shaping device for shaping a beam of the excitation light source to ensure that the excitation light source passes through the photoacoustic wave collecting cavity without collision; the gas measuring device also comprises a detector, wherein the detector is arranged right behind the light source emergent window and is used for monitoring the real-time working condition of the laser.
In the excitation light source part, the current driving module is responsible for controlling the wavelength of the emergent light of the excitation light source and modulating the excitation light by controlling the current; the temperature control module is responsible for accurately controlling the working temperature of the excitation light source through the PID circuit and ensuring that the output light wavelength is the set wavelength.
A gas detection method using a piezoelectric material-based gas measurement device specifically comprises the following steps:
(a) scanning to determine the resonant frequency f of the photoacoustic wave collection chamber0；
(b) Enabling emergent light of the excitation light source to be in f through the excitation light source current driving module0The frequency of/2 is modulated;
(c) the exciting light source is controlled by the exciting light source current driving module and the temperature control module to enable the working current of the laser to scan through the characteristic absorption line of the target gas, so that the target gas absorbs laser energy and releases an acoustic wave signal based on the photoacoustic effect;
(d) the acoustic signal enables the photoinduced acoustic wave collection cavity to periodically expand and contract so as to generate a piezoelectric signal, the piezoelectric signal is processed and amplified by the photoacoustic signal preprocessing module and converted into an electric signal to be transmitted to the phase-locked amplifying module, and the phase-locked amplifying module demodulates the electric signal by using the frequency doubling of the modulation frequency of the excitation light source;
(e) the phase-locked amplification module transmits the demodulated signal to a single chip microcomputer or a microcomputer, and the target gas concentration is obtained through mathematical calculation processing.
Further, during the measurement of said steps (a) - (e), the gas flow rate does not exceed 1000 sccm.
Compared with the prior art, the invention has the following beneficial effects:
1. the photoinduced sound wave collecting cavity designed by the invention is simple to manufacture and short in production cycle: for a conventional resonant photoacoustic cell, the geometric center of the photoacoustic cell needs to be perforated and fitted with a microphone, as shown by the dashed box in fig. 1; for the light induced sound wave collecting cavity, the whole cavity is of a sealed structure, and a hole is not required to be formed at the dotted line square frame in the figure 1 and a microphone is not required to be installed; in addition, the invention provides two manufacturing methods of the photoacoustic wave collecting cavity aiming at piezoelectric materials with different characteristics, the two methods are simple and easy to operate, the related process flows are conventional production processes which are commonly used in the industry and have complete technologies, and the product performance consistency of batch production is high;
2. the production cost of the designed photoinduced sound wave collecting cavity is extremely low: with the development of material technology, novel piezoelectric materials are continuously generated, the cost of the piezoelectric materials is continuously and greatly reduced, and the manufacturing cost of the photoinduced sound wave collecting cavity prepared based on the mass-produced piezoelectric materials is two to three orders of magnitude lower than that of the traditional photoacoustic cell. In addition, the piezoelectric material has piezoelectric property and can serve as an acoustoelectric transducer, so that high-efficiency detection of photoacoustic signals can be completed without additional equipment such as a high-sensitivity microphone or a tuning fork quartz crystal oscillator, and the cost of the photoinduced acoustic wave collecting cavity is further reduced.
3. The photoinduced sound wave collecting cavity designed by the invention is immune to environmental noise, and has good environmental noise interference resistance: the photoinduced sound wave collecting cavity is completely sealed in the hollow part in the sound insulation supporting component and isolated from the external environment, so that the device can be effectively prevented from being interfered by environmental noise compared with the traditional device and method for realizing gas concentration detection based on the photoacoustic effect;
4. the light-induced sound wave collecting cavity has high collection efficiency and photoelectric conversion efficiency on light and sound signals: in the traditional photoacoustic spectroscopy technology, for example, a photoacoustic spectroscopy device adopting a resonance type photoacoustic cell is adopted, only an acoustoelectric transducer is arranged at the antinode position of the harmonic wave of a photoacoustic signal (usually at the geometric central part of the resonance type photoacoustic cell) to collect the photoacoustic signal, but the photoinduced acoustic wave collecting cavity can collect the photoacoustic signal in the whole cavity, so that the collection efficiency and the photoelectric conversion efficiency of the photoacoustic signal are greatly improved;
5. the gas detection device of the invention has low requirement on the quality of the light beam of the photoacoustic signal excitation light source: the photo-induced acoustic wave collection cavity simultaneously realizes the functions of collecting the photoacoustic signals and performing sound-electricity conversion, so compared with the traditional photoacoustic spectroscopy technology which adopts a resonance type photoacoustic cell and a broadband microphone to realize the functions of collecting the photoacoustic signals and performing sound-electricity conversion, the photo-induced acoustic wave collection cavity can provide a large air cavity, thereby allowing a light source with poor light beam quality to serve as an excitation light source of the photoacoustic signals. Compared with the novel quartz enhanced photoacoustic spectroscopy technology which requires the diameter of the light beam of the excitation light source to be lower than 300 mu m, the invention has more prominent advantages;
6. the invention can fully utilize the high-voltage electric conversion coefficient characteristic of a novel piezoelectric material which is rapidly developed in recent years, and realize the effective output of a high-voltage electric signal by adopting the high-voltage electric conversion coefficient material, thereby realizing the detection of the target gas with higher sensitivity.
Drawings
Fig. 1 is a schematic diagram of the distribution of the intensity of acoustic waves in a photoacoustic cavity.
Fig. 2 is a schematic diagram of a process for manufacturing a photoacoustic wave collection cavity according to the present invention for a flexible piezoelectric material. Wherein (a) is a schematic representation of an inner wrap of a flexible piezoelectric material; (b) the inner surface, the outer surface and the bonding surface of the flexible piezoelectric material after being rolled up are schematically shown.
Fig. 3 is a schematic structural view of a piezoelectric photoacoustic cavity assembly and a sound-insulating support assembly according to the present invention.
FIG. 4 is a schematic view of a piezoelectric material based gas measurement device of the present invention.
Figure 5 is a frequency response curve of an example of the photoacoustic wave collection cavity.
Fig. 6 shows absorption lines of target gas detected by the gas measuring device and method according to the present invention.
FIG. 7 is a gas sampling and detection time response curve of the gas detection device of the present invention.
The device comprises a piezoelectric photoacoustic cavity component 1, a photoacoustic wave collecting cavity 11, a current collecting electrode 12, a sound insulating support component 2, a light source incidence window 21, a light source exit window 22, an air inlet 23, an air outlet 24, a photoacoustic cavity support frame 25, a conductive electrode 26, a laser current driving module 31, a laser temperature control module 32, an excitation light source 33, a light beam shaping device 4, a detector 5, a signal generator 61, a signal preprocessing circuit module 62, a phase-locked amplifying circuit module 63, a singlechip or microcomputer 7 and a microphone 8.
Detailed Description
The technical scheme of the invention is further explained by the specific embodiment in combination with the attached drawings. It should be understood by those skilled in the art that the specific embodiments are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
The piezoelectric material used in this example was lead zirconate titanate-5, and the piezoelectric coefficient of lead zirconate titanate-5 was d33＝6*10-10C/N, and preparing the photoinduced sound wave collecting cavity according to the geometrical size calculated theoretically by adopting a stacking method widely used in the industry. The internal diameter of the photoacoustic wave collection chamber made of this material was 0.45cm and the length was 3 cm. The lead zirconate titanate can alternatively have a piezoelectric coefficient greater than 2 x 10-12C/N other non-flexible piezoelectric materials.
As shown in fig. 3, a gas spectrum sound measuring apparatus based on piezoelectric material comprises a piezoelectric photoacoustic cavity assembly 1 made of piezoelectric material, a sound insulation support assembly 2, an excitation light source part and a signal processing assembly; the piezoelectric photoacoustic cavity assembly 1 comprises a photoacoustic wave collecting cavity 11 made of piezoelectric materials and two collecting electrodes 12 which are arranged on the inner wall and the outer wall of the photoacoustic wave collecting cavity and are used for collecting piezoelectric charges; the sound insulation supporting component 2 is provided with an air inlet 23, an air outlet 24, an excitation light source incidence window 21, an excitation light source exit window 22, a photoacoustic cavity supporting component 25 and two conductive electrodes 26, the air inlet 23 and the air outlet 24 are respectively positioned at the oblique symmetrical positions of the sound insulation supporting component 2, and the design can realize rapid exchange between air in the piezoelectric photoacoustic cavity and outside air, so that the response time of the device is reduced; the excitation light source incident window 21 and the excitation light source exit window 22 are respectively located on two end side surfaces of a hollow part of the photoacoustic wave collection cavity 11, the photoacoustic cavity support component 25 fixes the photoacoustic wave collection cavity 11 on the inner wall of the sound insulation support component 2, and makes the entrance and the exit of the excitation light source incident window 21, the excitation light source exit window 22 and the photoacoustic wave collection cavity 11 located on the same straight line, the two conductive electrodes 26 independently penetrate through the side wall of the sound insulation support component 2 and are mutually insulated from the sound insulation support component 2, one end of each conductive electrode 26 located on the inner side of the sound insulation support component 2 is respectively connected with the two current collecting electrodes 12 on the photoacoustic wave collection cavity 11, and one end of the outer side is respectively connected with the input end of the signal preprocessing module 62; the modulated laser passes through the incident window 21 and the exit window 22, acts with the target gas to be measured to generate sound waves, and the sound waves do not collide with the target gas to pass through the photoinduced sound wave collecting cavity 11 which is fixed at the middle position of the sound insulation supporting component by the photoacoustic cavity supporting frame 25; the periodic expansion and contraction of the photoacoustic wave collection cavity 11 generates a piezoelectric signal, which is output from the current collecting electrode 12 connected to the inner and outer surfaces of the photoacoustic wave collection cavity and the conductive electrode 26 on the sound-proof support assembly 2 to the input end of the signal preprocessing module 62.
The excitation light source part comprises an excitation light source 33 and an excitation light source drive, the excitation light source drive comprises a current drive module 31 and a laser temperature control module 32, and the outputs of the current drive module 31 and the laser temperature control module 32 are both connected with the excitation light source 33; the signal processing assembly comprises a signal generator 61, a signal preprocessing circuit module 62, a phase-locking amplifying circuit module 63 and a single chip microcomputer or a microcomputer 7, wherein a signal output end of the signal generator 61 is connected with the current driving module 31, a synchronous signal output end of the signal generator 61 is connected with a synchronous signal input end of the phase-locking amplifying circuit module 63, an output of the signal preprocessing circuit module 62 is connected with a signal input end of the phase-locking amplifying circuit module 63, and an output of the phase-locking amplifying circuit module 63 is connected with the single chip microcomputer or the microcomputer 7.
The photoacoustic cavity supporting component 25 is an annular outer support which is structurally matched with the photoacoustic wave collecting cavity 11 and is composed of two semicircular supports, and the annular outer support is annularly arranged on the outer surface of the photoacoustic wave collecting cavity 1 to realize the positioning and fixing effects on the photoacoustic wave collecting cavity 11.
When the requirement on the gas detection sensitivity in the application field is not high, or the characteristics of the piezoelectric material are enough to meet the detection sensitivity requirement, the inner surface and the outer surface of the photoinduced acoustic wave collection cavity do not need to be coated or grown with a conductive film. In this application example, in order to fully collect the piezoelectric charges distributed on the surface of the photoacoustic wave collection cavity 11, in this embodiment, the inner and outer surfaces of the photoacoustic wave collection cavity 11 are respectively coated with conductive silver paste, so as to ensure that the conductive silver pastes on the inner and outer surfaces of the photoacoustic wave collection cavity 11 are insulated from each other, and the conductive silver paste has good conductive contact with the current collection electrode 12 on the same surface.
The excitation light source adopted in the embodiment is an optical fiber coupling distributed feedback diode laser, and the optical fiber coupling lens is selected to shape the emergent light beam of the laser, so that the light beam is shaped into a parallel collimated light beam with the diameter of 200 microns, and the excitation light source can pass through the photoacoustic wave collecting cavity 1 without collision. The quality of the light beam can meet the requirement of an exciting light source penetrating through the light induced sound wave collecting cavity without collision, and a light beam shaper is not needed.
The laser detection device further comprises a detector 5, wherein the detector 5 is an indium gallium arsenic detector, is arranged right behind the light source emergent window 22 and is used for monitoring the real-time working condition of the laser. The detector 5 is not an essential device of the apparatus of the present invention, i.e. in an application environment where the detection of the laser power is not required, the detector 5 may not be installed.
As shown in fig. 4, the gas detection method using the gas spectrum acoustic measurement device based on piezoelectric material according to the present invention includes the following steps: the signal generator 61 generates a frequency f0The sinusoidal modulation signal of/2 is given to the laser current driving module 31; the current driving module 31 controls the wavelength of the light emitted by the excitation light source 33 and modulates the excitation light by controlling the current; laserThe temperature control module 32 precisely controls the working temperature of the excitation light source 33 through a PID circuit to ensure that the output light wavelength is the set wavelength; when the excitation light source beam quality is poor, the beam shaping device 4 is used to optimize the beam quality to ensure that the excitation light source passes through the photoacoustic wave collection cavity 11 without collision; the detector 5 is arranged right behind the light source emergent window and used for monitoring the real-time working condition of the laser; the piezoelectric charge signal given by the conductive electrode 26 enters the signal preprocessing module 62, is converted into a voltage signal by the signal preprocessing module 62, and is transmitted to the phase-locking amplifying circuit module 63; the frequency f of the phase-locked amplifying module 63 received and transmitted by the signal generator 610A/2 reference signal and second harmonic demodulation is carried out on the electric signal; the phase-locked amplifying module 63 transmits the demodulated signal to the single chip microcomputer or the microcomputer 7, and the microcomputer 7 obtains the external output or display of the target gas concentration through the mathematical calculation processing known in the industry.
When the gas detection device is used for gas detection, the gas flow rate does not exceed 1000 sccm.
The following is a verification of the frequency response curve of the core device photoacoustic wave collection cavity of the present invention.
As shown in fig. 5, is a frequency response curve of the photo-induced acoustic wave collection chamber used in the embodiment.
The frequency response curve of the photoacoustic wave collection cavity is obtained by scanning the modulation frequency of the laser, and the specific operation steps are as follows:
an optical fiber coupling distributed feedback diode laser with the center wavelength of 1368nm is selected as a photoacoustic signal excitation light source. When the parameters of the laser current driving module 31 and the laser temperature control module 32 are set to 25 ℃ and 98mA, the output wavelength of the excitation light source is 7306.75cm-1The wavelength is a characteristic absorption line of water molecules, and the interference of absorption lines of other common gas molecules such as carbon dioxide and the like does not exist nearby the characteristic absorption line. The signal generator 61 is adjusted to scan the modulation frequency of the excitation light source 33 in the range of 0KHz to 10KHz and generate photoacoustic signals of different frequencies, and the photoacoustic signal is induced and converted into an electrical signal pair by the photo-induced acoustic wave collecting cavity made of piezoelectric materialAnd externally outputting, wherein in the process that the frequency of the photoacoustic signal is continuously close to the resonant frequency of the photoacoustic wave collecting cavity, the response amplitude of the photoacoustic wave collecting cavity to the photoacoustic signal with the same strength is continuously enhanced until the photoacoustic signal reaches the maximum due to the resonance effect under the condition that the frequency of the photoacoustic signal is equal to the resonant frequency of the photoacoustic wave collecting cavity. Fig. 5 shows only the frequency response curve around the resonant frequency of the photoacoustic wave collection cavity, with the abscissa of the graph being the actual demodulation frequency. As can be seen from the frequency response curve of the photoacoustic wave collecting cavity shown in FIG. 5, the resonant frequency of the photoacoustic wave collecting cavity used in the application example was 3300 Hz. In the subsequent application example, 3300Hz is used as the resonant frequency of the photoacoustic wave collection cavity, and the photoacoustic signal is detected by second harmonic modulation and demodulation technology, i.e. in the subsequent example, the frequency of the modulation signal of the laser is set to 1650Hz, and the demodulation frequency is set to 3300 Hz.
Fig. 6 shows photoacoustic signals obtained by detection based on the apparatus and method of the present invention, and example data acquisition steps are as follows:
the sinusoidal modulation signal with the frequency of 1650Hz generated by the signal generator 61 is sent to the laser current driving module 31, so that the wavelength of the emergent light of the excitation light source is modulated with the frequency of 1650 Hz; at the same time, the laser current driving module 31 generates a set of periodic ramp voltage signals, which can make the driving current transmitted to the excitation light source scan slowly from 80mA to 120 mA. While the laser driving current is scanned, the working temperature of the excitation light source is stably controlled at 25 ℃ under the action of the laser temperature control module 32. The excitation light source outputs modulation frequency of 1650Hz and wavelength sweeps 7306.75cm slowly under the action of the laser current driving module 31 and the laser temperature control module 32-1Collimated through the photoacoustic wave collection cavity 11. Further, when the excitation light source beam quality is poor, the beam shaping device 4 is used to optimize the beam quality to ensure that the excitation light source does not collide through the photoacoustic wave collection cavity 11. The detector 5 is arranged right behind the light source emergent window and used for monitoring the real-time working condition of the laser, and in addition, the detector 5 can be ignored and not used in the actual use process; piezoelectric charge given by conductive electrode 26The signal enters the signal preprocessing module 62; the signal preprocessing module 62 converts the piezoelectric charge signal into a voltage signal, amplifies the voltage signal and transmits the amplified voltage signal to the phase-locked amplifying circuit module 63; the phase-locked amplification module 63 receives the reference signal with a frequency of 1650Hz transmitted by the signal generator 61, and performs harmonic demodulation on the electrical signal by using the frequency doubling (i.e. 3300Hz) of the reference signal, so as to obtain the second harmonic line of the target gas shown in fig. 6. The phase-locked amplifying module 61 transmits the demodulated signal to the singlechip or microcomputer 7, and the singlechip or microcomputer 7 performs calculation processing to obtain the target gas concentration and outputs or displays the target gas concentration. The singlechip or microcomputer 7 processes data by adopting a calculation method well known in the field of gas detection, and specifically, the device is adopted to measure the known concentration C0Such as the target gas water vapor measured in the present application example, to obtain a corresponding spectral signal S0(S0Maximum of the second harmonic curve shown in fig. 6); then measuring target gas with unknown concentration C to obtain spectral signal ScAnd further, according to the characteristic that the amplitude of the photoacoustic spectrum signal is in positive correlation with the concentration of the target gas, calculating to obtain the concentration C of the measured target gas, which is Sc·C0/S0。
As shown in fig. 7, the measurement steps of the gas sampling and detection time response curve of the device of the present invention are as follows:
controlling parameters of the laser current driving module 31 and the laser temperature control module 32 to keep the wavelength of the output light of the excitation light source at 7306.75cm-1At this time, for the target gas with the same concentration, the spectrum signal output from the photoacoustic wave collection cavity to the outside will remain unchanged. In an application example, dry nitrogen is filled into the photoinduced sound wave collecting cavity, the mean value of an output signal of the device to the outside is zero at the moment, the amplitude of signal jitter is the background noise of the device, water vapor with constant concentration is filled into the photoinduced sound wave collecting cavity at the moment when t is 150s and lasts for a period of time, the flow rate of the filled gas is 100sccm, the result shows that the photoinduced sound wave collecting cavity responds to the change of the water vapor concentration while the water vapor enters the device, the output signal starts to continuously rise, and the device outputs a signal after 9s gas exchangeAnd (3) stabilizing to realize stable detection of the target gas, then refilling dry nitrogen into the device when t is 320s, enabling the photoacoustic signal output by the device to start to fall, and enabling the signal to be stabilized at the background noise amplitude of the device after 8 s. The above results verify the stability of the device in long-term operation and the rapid response characteristics to concentration variations.
The photoacoustic wave collecting cavity in the above embodiments can also be made of flexible piezoelectric materials, such as polyvinylidene fluoride materials, hybrid perovskites, etc., with a piezoelectric coefficient greater than 2 x 10-12The C/N flexible piezoelectric material is specifically manufactured as shown in fig. 2(a), the process of manufacturing the photoacoustic wave collection cavity by using the flexible piezoelectric material comprises the steps of cutting the flexible material into a rectangular sheet structure according to the size of a cavity calculated theoretically, then rolling the flexible material into a cylinder shape according to the direction indicated by an arrow, and as a result of rolling, the inner surface and the outer surface of the flexible piezoelectric material have mutually overlapped areas as shown in fig. 2 (b), and then coating insulating glue on the overlapped areas for bonding. The reason why the insulating glue is used for bonding is to avoid the electric conduction of the glue, so that the piezoelectric charges respectively generated by the piezoelectric material under the action of the photoacoustic signal and respectively positioned on the inner surface and the outer surface of the material are neutralized. Furthermore, the area of the overlapped area of the upper surface and the lower surface is moderate, the overlapped length is controlled to be 4% -7% of the length of the flexible material before being curled, the overlapped length ensures the stability of adhesion, and the excessive piezoelectric charge loss caused by the overlarge adhered area can be avoided.
Claims (8)
1. A gas measuring device based on piezoelectric material, characterized in that: the device comprises a piezoelectric photoacoustic cavity component (1) made of piezoelectric materials, a sound insulation supporting component (2), an excitation light source part and a signal processing component; the piezoelectric photoacoustic cavity assembly (1) comprises a photoinduced acoustic wave collecting cavity (11) made of piezoelectric materials and two collecting electrodes (12) which are arranged on the inner wall and the outer wall of the photoinduced acoustic wave collecting cavity and are used for collecting piezoelectric charges; the sound insulation support assembly (2) is provided with an air inlet (23), an air outlet (24), an excitation light source incident window (21), an excitation light source exit window (22), a photoacoustic cavity support assembly (25) and two conductive electrodes (26), the air inlet (23) and the air outlet (24) are respectively positioned at the oblique symmetrical positions of the sound insulation support assembly (2), the excitation light source incident window (21) and the exit window (22) are respectively positioned at the two end side surfaces of the hollow part of the photoacoustic wave collection cavity (11), the photoacoustic cavity support assembly (25) fixes the photoacoustic wave collection cavity (11) on the inner wall of the sound insulation support assembly (2), and enables the inlets and outlets of the excitation light source incident window (21), the excitation light source exit window (22) and the photoacoustic wave collection cavity (11) to be positioned on the same straight line, and the two conductive electrodes (26) are arranged on the side wall of the sound insulation support assembly (2), the two conductive electrodes (26) are insulated from the sound insulation supporting component (2), one ends of the two conductive electrodes (26) positioned on the inner side of the sound insulation supporting component (2) are respectively connected with the two current collecting electrodes (12) on the photoinduced sound wave collecting cavity (11), and one ends of the outer sides of the two conductive electrodes are respectively connected with the input end of the signal preprocessing module (62); the excitation light source part comprises an excitation light source (33) and an excitation light source drive, the excitation light source drive comprises a current drive module (31) and a laser temperature control module (32), and the outputs of the current drive module (31) and the laser temperature control module (32) are connected with the excitation light source (33); the signal processing assembly comprises a signal generator (61), a signal preprocessing circuit module (62), a phase-locked amplifying circuit module (63) and a single chip microcomputer or a microcomputer (7), wherein a signal output end of the signal generator (61) is connected with the current driving module (31), a synchronous signal output end of the signal generator (61) is connected with a synchronous signal input end of the phase-locked amplifying circuit module (63), an output of the signal preprocessing circuit module (62) is connected with a signal input end of the phase-locked amplifying circuit module (63), and an output of the phase-locked amplifying circuit module (63) is connected with the single chip microcomputer or the microcomputer (7); the photoinduced sound wave collecting cavity (11) made of the piezoelectric material is manufactured by the following specific method: curling a rectangular flexible piezoelectric material into a cylinder shape for the flexible piezoelectric material which is soft and can be curled, enabling the inner surface and the outer surface of the flexible piezoelectric material to have an overlapping area, bonding the overlapping area by adopting insulating glue to prepare a photoacoustic wave collecting cavity, and bonding current collecting electrodes (12) on the inner surface and the outer surface of two ends of the photoacoustic wave collecting cavity respectively by adopting conductive glue; the photoinduced sound wave collecting cavity (11) is sealed in the hollow part in the sound insulation supporting component (2) and is isolated from the external environment; the photoacoustic wave collection cavity (11) can collect photoacoustic signals in the whole cavity; the photo-induced acoustic wave collecting cavity (11) can simultaneously complete the collection of the photoacoustic signals and the acoustoelectric conversion.
2. A piezoelectric material based gas measurement device as claimed in claim 1, wherein: the piezoelectric material is a flexible or non-flexible material with piezoelectric property, and the piezoelectric material has a piezoelectric coefficient greater than 2 x 10-12C/N piezoelectric materials.
3. A piezoelectric material-based gas measurement device as claimed in claim 1, wherein: the overlapping length of the overlapping area is controlled to be between 4% and 7% of the circumferential length of the cylinder; the non-flexible piezoelectric material is directly prepared by adopting a stacking or co-sintering method.
4. A piezoelectric material based gas measurement device as claimed in claim 1, wherein: the optical-acoustic cavity supporting component (25) is an annular outer support matched with the structure of the optical-acoustic wave collecting cavity (11), the annular outer support is composed of two semicircular supports, the inner side of the annular outer support is tightly contacted with the outer surface of the optical-acoustic wave collecting cavity (1), and the outer side of the annular outer support is fixed on the inner wall of the sound insulation supporting component (2), so that the positioning and fixing effects of the optical-acoustic wave collecting cavity (11) are realized.
5. A piezoelectric material based gas measurement device as claimed in claim 1, wherein: in order to fully collect the piezoelectric charges distributed on the surface of the photoinduced sound wave collecting cavity (11), conductive films can be respectively grown or coated on the inner surface and the outer surface of the photoinduced sound wave collecting cavity (11), the conductive films on the inner surface and the outer surface of the photoinduced sound wave collecting cavity (11) are ensured to be mutually insulated, and the conductive films are in good conductive contact with the collecting electrodes (12) on the same surface.
6. A piezoelectric material based gas measurement device as claimed in claim 1, wherein: the excitation light source part can also comprise a light beam shaping device (4) for shaping the light beam of the excitation light source so as to ensure that the excitation light source passes through the light induced sound wave collecting cavity (1) without collision; the gas measuring device further comprises a detector (5), wherein the detector (5) is arranged right behind the light source exit window (22) and used for monitoring the real-time working condition of the laser.
7. A gas measuring method using the piezoelectric material-based gas measuring device according to any one of claims 1 to 6, characterized in that: the method comprises the following steps:
(a) scanning to determine the resonant frequency f of the photoacoustic wave collection chamber0；
(b) Enabling the wavelength of the emergent light of the excitation light source to be f through the excitation light source current driving module0Frequency modulation of/2;
(c) the exciting light source is controlled by the exciting light source current driving module and the temperature control module to enable the working current of the laser to scan through the characteristic absorption line of the target gas, so that the target gas absorbs laser energy and releases an acoustic wave signal based on the photoacoustic effect;
(d) the acoustic signal enables the photoinduced acoustic wave collection cavity to periodically expand and contract so as to generate a piezoelectric signal, the piezoelectric signal is transmitted to the photoacoustic signal preprocessing module through the signal output line by the current collection electrode, and then is amplified and converted into a voltage signal by the photoacoustic signal preprocessing module and then is transmitted to the phase-locked amplifying module, and the phase-locked amplifying module demodulates the electric signal by using the frequency doubling of the modulation frequency of the excitation light source;
(e) the phase-locked amplifying module transmits the demodulated signal to a single chip microcomputer or a microcomputer, and the concentration of the target gas to be detected is obtained through mathematical calculation processing;
the photoinduced sound wave collecting cavity (11) made of the piezoelectric material is manufactured by the following specific method: curling a rectangular flexible piezoelectric material into a cylinder shape for the flexible piezoelectric material which is soft and can be curled, enabling the inner surface and the outer surface of the flexible piezoelectric material to have an overlapping area, bonding the overlapping area by adopting insulating glue to prepare a photoacoustic wave collecting cavity, and bonding current collecting electrodes (12) on the inner surface and the outer surface of two ends of the photoacoustic wave collecting cavity respectively by adopting conductive glue; the light induced sound wave collecting cavity (11) is sealed in the hollow part in the sound insulation supporting component (2) and is isolated from the external environment; the photo-induced sound wave collecting cavity (11) can collect the photo-acoustic signals in the whole cavity; the light-induced sound wave collecting cavity (11) can simultaneously complete the collection of the photoacoustic signals and the acoustoelectric conversion.
8. The gas measuring method using the piezoelectric-material-based gas measuring apparatus according to claim 7, characterized in that: during the measurement in said steps (a) - (e), the gas flow rate does not exceed 1000 sccm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110127194.1A CN112858184B (en) | 2021-01-29 | 2021-01-29 | Gas measuring device and method based on piezoelectric material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110127194.1A CN112858184B (en) | 2021-01-29 | 2021-01-29 | Gas measuring device and method based on piezoelectric material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112858184A CN112858184A (en) | 2021-05-28 |
| CN112858184B true CN112858184B (en) | 2022-07-19 |
Family
ID=75986897
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110127194.1A Active CN112858184B (en) | 2021-01-29 | 2021-01-29 | Gas measuring device and method based on piezoelectric material |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112858184B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114061889A (en) * | 2021-12-14 | 2022-02-18 | 南京航空航天大学 | Ultrasonic same-frequency observation device and method for directly displaying second modal wave |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101514960A (en) * | 2009-03-23 | 2009-08-26 | 吉林市中准仪表开发有限责任公司 | SF* detecting system based on photoacoustic spectroscopic technology |
| WO2020157022A1 (en) * | 2019-01-28 | 2020-08-06 | Universiteit Gent | Photoacoustic transducer |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7245380B2 (en) * | 2002-06-10 | 2007-07-17 | William Marsh Rice University | Quartz-enhanced photoacoustic spectroscopy |
| US7805980B2 (en) * | 2004-02-09 | 2010-10-05 | William Marsh Rice University | Selectivity enhancement in photoacoustic gas analysis via phase-sensitive detection at high modulation frequency |
| US8102532B2 (en) * | 2008-01-02 | 2012-01-24 | William Marsh Rice University | Resonant optothermoacoustic detection of optical absorption |
| US20110072886A1 (en) * | 2009-09-30 | 2011-03-31 | Catherine Genevieve Caneau | Gas Sensor Based On Photoacoustic Detection |
| CN103411904B (en) * | 2013-07-30 | 2015-10-14 | 中国科学院合肥物质科学研究院 | Based on the photoacoustic gas sensing device of poly meta fluoroethylene piezoelectric film |
| CN103884419B (en) * | 2014-04-17 | 2017-01-11 | 山西大学 | Tuning fork type quartz crystal oscillator resonant frequency measurement method based on optical excitation and device |
| 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 |
| CN104697933B (en) * | 2015-03-04 | 2017-06-16 | 中国科学院合肥物质科学研究院 | Triple channel acoustic resonant cavity optoacoustic spectroscopy sensing device |
| GB201516524D0 (en) * | 2015-09-17 | 2015-11-04 | Fraunhofer Uk Res Ltd | Detector |
| CN105241814A (en) * | 2015-10-13 | 2016-01-13 | 安徽皖仪科技股份有限公司 | Apparatus and method for measurement of trace gas with photoacoustic spectroscopy technology |
| CN105259116A (en) * | 2015-10-13 | 2016-01-20 | 安徽皖仪科技股份有限公司 | Trace gas measurement device and method with adoption of photo-acoustic spectroscopy |
| US10228322B2 (en) * | 2017-07-13 | 2019-03-12 | Cymer LLC | Apparatus for and method of sensing fluorine concentration |
| CN111272663B (en) * | 2020-02-10 | 2021-02-02 | 山西大学 | Gas detection device and method |
| CN111220513A (en) * | 2020-03-23 | 2020-06-02 | 石家庄铁道大学 | Haze detection device and method based on digital phase locking and photoacoustic spectroscopy technology |
| CN111678592A (en) * | 2020-07-01 | 2020-09-18 | 西安柯莱特信息科技有限公司 | Pulse light detector based on photoacoustic effect |
-
2021
- 2021-01-29 CN CN202110127194.1A patent/CN112858184B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101514960A (en) * | 2009-03-23 | 2009-08-26 | 吉林市中准仪表开发有限责任公司 | SF* detecting system based on photoacoustic spectroscopic technology |
| WO2020157022A1 (en) * | 2019-01-28 | 2020-08-06 | Universiteit Gent | Photoacoustic transducer |
Non-Patent Citations (3)
| Title |
|---|
| A novel photoacoustic spectroscopy gas sensor using a low cost polyvinylidene fluoride film;KunLi;《Sensors and Actuators B: Chemical》;20181220;第277卷;全文 * |
| Photoacoustic spectroscopy for gas sensing: A comparison between piezoelectric and interferometric readout in custom quartz tuning forks;StefanoDello;《Photoacoustics》;20200331;第17卷;全文 * |
| 石英晶体的光声光谱法CO_2浓度检测技术研究;陈亮等;《沈阳理工大学学报》;20150415(第02期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112858184A (en) | 2021-05-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107064012B (en) | Quartz enhanced photoacoustic spectroscopy gas-detecting device and method based on beat effect | |
| CN104237135B (en) | CO gas detecting systems and method based on quartz tuning fork strengthened optoacoustic spectroscopy | |
| CN102713565A (en) | Gas sensor based on photoacoustic detection | |
| US10520365B2 (en) | Detector for terahertz electromagnetic waves | |
| KR101374679B1 (en) | Method for measuring the pressure and/or molar mass of a gas in a housing, and corresponding measurement assembly | |
| JP2008532036A (en) | Photoacoustic spectroscopy detector and system | |
| Sun et al. | Mid-Infrared quartz-enhanced photoacoustic sensor for ppb-level CO detection in a SF6 gas matrix exploiting a T-grooved quartz tuning fork | |
| WO2003104767A2 (en) | Quartz-enhanced photoacoustic spectroscopy | |
| Goldan et al. | An acoustically resonant system for detection of low‐level infrared absorption in atmospheric pollutants | |
| CN112858184B (en) | Gas measuring device and method based on piezoelectric material | |
| CN112903597A (en) | Gas detection system and method based on graphene coated quartz tuning fork | |
| CN113252573B (en) | Photo-thermal spectrum trace gas detection device and method based on cavity enhancement | |
| CN112834430B (en) | Gas detection device and method based on acoustic pulse excitation of photoacoustic cell | |
| CN104931427A (en) | Opto-acoustic gas detection device based on multiple reflections of optical path | |
| CN112504966B (en) | Silicon tuning fork microphone for photoacoustic spectrum detection | |
| US10663432B2 (en) | Gas sensor and gas detection method | |
| CN108981898A (en) | It is a kind of to realize the method for micro-cantilever resonant frequency tuning using photo-thermal effect, realizing system and application | |
| CN104237154A (en) | Device for detecting methane and carbon dioxide in atmospheric greenhouse gas based on photoacoustic spectrum technology | |
| CN109916853A (en) | Laser infrared spectrum trace materials detection device and method based on fiber grating | |
| CN109669110A (en) | Sound focusing sensor and PD On-Line Measurement System and its detection method for shelf depreciation on-line checking | |
| CN113552212B (en) | Radial cavity quartz enhanced photoacoustic spectrum sound detector and gas detection device thereof | |
| CN107991240B (en) | Multifunctional photoelectric detector based on quartz tuning fork resonance principle | |
| CN106290165A (en) | General frequency strengthens optoacoustic spectroscopy acousimeter and uses the gas detection apparatus of this acousimeter | |
| Spagnolo et al. | Part-per-trillion level detection of SF6 using a single-mode fiber-coupled quantum cascade laser and a quartz enhanced photoacoustic sensor | |
| CN113340847A (en) | Phi-shaped quartz tuning fork and trace gas detection device based on phi-shaped quartz tuning fork |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |