210 results about "Quartz tuning fork" patented technology

The invention discloses a quartz tuning fork strengthened photoacoustic spectroscopy gas sensor based on an acoustic resonator. The gas sensor comprises a laser (1), a focusing lens (5), a tubular resonator, a quartz tuning fork (11), a function generator (15) electrically connected with the laser (1) and a lock-in amplifier (14) electrically connected with the quartz tuning fork (11), wherein the focusing lens (5) and the tubular resonator are arranged on an optical path (2) of the laser (1); the function generator (15) is electrically connected with the lock-in amplifier (14); the tubular resonator is the acoustic resonator (9) with a slit (91) in the middle; the length of the acoustic resonator is not more than 10mm, the external diameter is not more than 1mm and the internal diameter is not more than 0.6mm; the width of the slit (91) is not more than 0.2mm and the length is not more than the internal diameter of the acoustic resonator (9); prongs (111) of the quartz tuning fork (11) are positioned on the slit (91) and the distances between the prongs (111) and the slit (91) are not less than 0.001mm. The gas sensor has simple structure, small volume and strong anti-jamming property, works stably, is convenient to adjust and use and can be extensively used for detecting the components or contents of the gases.

The invention provides a system and a method for detecting CO gas based on a quartz tuning fork enhanced photoacoustic spectrometry technology, relates to a system and a method for detecting the CO gas and aims at solving the problem of low detection accuracy of the existing CO gas photoacoustic spectrometry detection technology. A data processing module transmits a current control signal to a laser device controller via a function generator, and meanwhile, transmits a temperature control parameter to the laser device controller; the laser device controller drives a laser device to emit near infrared laser which is incident into a gas chamber after being collimated and focused; the gas absorbs optical energy so that the optical energy is converted into heat energy and further converted into an acoustic pressure signal; a quartz tuning fork mounted in the gas chamber converts an acoustic signal into an electric signal; the electric signal of the quartz tuning fork is converted and amplified and then input into the measurement channel input end of a phase-locked amplifier; the phase-locked amplifier inverts the concentration of the CO gas to be detected by performing secondary harmonic detection in combination with the reference signal of the function generator. The system and the method for detecting the CO gas based on the quartz tuning fork enhanced photoacoustic spectrometry technology are applicable to CO gas detection.

The invention discloses a quartz tuning fork photoacoustic gas sensing device based on a broadband light source dual-wavelength difference. A pipy resonant cavity with a slit and a quartz tuning fork are arranged in a sample pool. In the device, a laser diode is used for probing non absorption background noise, the other laser diode is used for probing nitrogen dioxide, coupling and beam splitting are carried out on the two laser diodes through a beam splitting prism, a photoelectric probe is used for monitoring the power of the laser diodes, light is focused to the pipy resonant cavity by a focusing lens, the output end of the quartz tuning fork is connected with the input end of a phase-locked amplifier, the focus of the focusing lens is arranged in the pipy resonant cavity, the output end of a high frequency square wave generator is electrically connected with the input end of the phase-locked amplifier, and the photoelectric probe, the high frequency square wave generator and a lower frequency square wave generator are connected with an external computer.

The invention relates to an enhanced multi-group photoacoustic spectrum gas sensing device based on a quartz tuning fork and belongs to the field of a photoacoustic spectrum detection technology. According to the invention, the quartz tuning fork with high quality factor is used to replace a traditional broadband microphone so as to broaden the dynamic range and realize miniaturization of the whole gas sensing device. By arranging a fiber-optic amplifier between a light source and an optical fiber coupler, laser output power of the light source is increased. Thus, it is easy to capture a weak photoacoustic signal generated by the quartz tuning fork, and detection sensitivity of the gas sensing device can be enhanced.

The invention discloses a gas sensor based on photoacoustic spectrometry, comprising a circuit matched and connected with a light source (1) and a quartz tuning fork (13). The gas sensor is characterized in that an acoustic resonator (6) is composed of a main tube (11) with a branch tube (12) which are communicated with each other vertically; the tube axis of the main tube (11) is coaxial with a light path (2), the tube length of the main tube (11) is 4.57-7.87 mm, and the tube inner diameter of the main tube (11) is 0.4-1.5mm; the tube length of the branch tube (12) is 1-2mm and the tube inner diameter of the branch tube (12) is 0.4-0.5mm; the focus of a focusing lens (4) is located at the communicated part of the main tube (11) and the branch tube (12); the plane and the slit centre of a tuning fork arm (131) of the quartz tuning fork (13) are vertical to and located in the axis of the branch tube (12) respectively, and the distance between the plane of the tuning fork arm (131) and the tail port of the branch tube (12) is 20-50mu m; and the slit width of the tuning fork arm (131) of the quartz tuning fork (13) is 0.28-0.32mm, and the resonant frequency of the tuning fork arm (131) of the quartz tuning fork (13) is 31.768-33.768kHz. The gas sensor based on photoacoustic spectrometry realizes coupling between a light-excited acoustic energy and the quartz tuning fork with the highest efficiency and can be used for the field of trace gas detection.

The invention discloses a silicon substrate-based quartz resonance acceleration sensor chip with a four-beam structure. The quartz resonance acceleration sensor chip comprises a periphery silicon substrate support, wherein the periphery silicon substrate support is bonded with a glass substrate; a double-end quartz tuning fork is fixed on a boss of the silicon substrate support through organic gel; and the other end is fixed on a boss of a mass block; the mass block is provided with four cantilever beams supported on the silicon substrate; a layer of metal electrode is arranged at the part (corresponding to the mass block) on the glass substrate; the metal electrode is used for preventing the electrostatic adherence between an acceleration mass block and the glass substrate during the electrostatic bonding; the sensor chip senses the input of the acceleration through the mass block, the double-end quartz tuning fork is thereby transformed, a resonance frequency of the quartz tuning fork is output through a frequency detecting circuit, and an acceleration signal is converted into an electric signal so as to accomplish the digital induction and measurement to the acceleration. The sensor chip has the advantages of good frequency output, small size, high sensitivity, high quality factor and the like.

The embodiment of the invention relates to the technical field of laser detection and in particular relates to an inner cavity enhanced photoacoustic spectrum type trace gas sensor device. The device comprises a semiconductor laser device, a wave chopper, a laser collimation and focusing system, a front cavity mirror, a tunable filter, a laser gain medium, a quartz tuning fork and a rear cavity mirror, which are sequentially arranged along a beam propagation direction; a piezoelectric signal generated by the quartz tuning fork is amplified by an impedance amplifier and then is transmitted to a control and data acquisition system; the control and data acquisition system is used for detecting resonance frequency of the quartz tuning fork and controlling the wave chopper in real time so that modulation frequency f is the resonance frequency f0 of the quartz tuning fork all the time; the computer is connected with the control and data acquisition system and real-time control is carried out through upper computer software Labview. The device provided by the invention can be used for rapidly detecting various types of trace gas in an atmospheric environment.

The invention discloses a photoacoustic spectrometry gas detection device capable of correcting the resonant frequency of a quartz tuning fork in real time, and belongs to the field of signal generation and correction in photoacoustic spectrometry gas detection technology. The device comprises a PC (personal computer), a signal generator, a gating switch, a laser device controller, a laser device, a collimator, a convex lens, a gas chamber, the quartz tuning fork, a quartz tuning fork module circuit, a current-to-voltage module, a front amplifier, a phase-locked amplifier and a data acquisition card. According to the device, the resonant frequency of the quartz tuning fork is measured by harmonic detection and peak detection, and a measurement result is used for correcting the frequency of a drive signal source in a photoacoustic spectrometry system in real time; a part for measuring the resonant frequency of the tuning fork is simple in structure, a method is novel, and the harmonic detection precision is high; the device is easily integrated with the photoacoustic spectrometry system and is low in additional cost and convenient and flexible to use, the influence due to drift of the resonant frequency of the tuning fork in photoacoustic spectrometry gas detection can be inhibited in actual application, and the system stability is improved.

A silicon substrate differential motion quartz acceleration sensor comprises two silicon substrates which are installed in the opposite directions and two-end-fixed quartz tuning forks, the silicon substrates are clamped between an upper overload protection plate and a lower overload protection plate, a structure formed by the silicon substrates, the two-end-fixed quartz tuning forks, the upper overload protection plate and the lower overload protection plate is placed in a hole of a circuit board, the two-end-fixed quartz tuning forks penetrate through through holes of the upper overload protection plate and are connected to the circuit board through gold wires, an inverse piezoelectric effect exists in the two-end-fixed quartz tuning forks, a circuit is adopted to inspire vibration, when acceleration acts on mass blocks supported by flexibility silicon beams, a differential motion structure is formed by the two two-end-fixed quartz tuning forks, and an output signal of the sensor is the difference of the frequency of the two two-end-fixed quartz tuning forks. When the temperature changes, the two two-end-fixed quartz tuning forks are pulled or pressed simultaneously, frequency changes are identical, the temperature affect can be offset through the subtraction of the frequency changes, the silicon substrate differential motion quartz acceleration sensor has the advantages of being small in size, light in weight and high in digital signal output and resolution ratio.

The invention relates to a tunable laser frequency stabilizing device capable of reinforcing the gas photoacoustic spectroscopy on the basis of a quartz tuning fork, which comprises a tunable laser, a modulation current source, a temperature controller, an optical fiber coupler, a closed gas chamber, the quartz tuning fork, a preamplifier, a phase sensitive detector and a control box, wherein the output end of the modulation current source is connected with the input end of the tunable laser; the output end of the temperature controller is connected with the input end of the tunable laser; the input end of the optical fiber coupler is connected with the output end of the tunable laser; an optical fiber focusing lens is arranged on one side wall of the closed gas chamber; the optical fiber focusing lens extends into the closed gas chamber; the quartz tuning fork is positioned in the closed gas chamber; the preamplifier is used for receiving a signal output by the quartz tuning fork; the input end of the phase sensitive detector is connected with the output end of the preamplifier; the input end of the control box is connected with the output end of the phase sensitive detector; and the modulation current source and the temperature controller are controlled by two output ends of the control box. The invention can solve the problems of high background noise, large size, poor structural stability and the like in a conventional gas adsorption spectrum frequency stabilizing technology adopting a direct adsorption method.

The invention discloses a quartz tuning-fork enhanced-type photo-acoustic spectrum gas cell, which comprises a first c-lens collimating lens (4), a second c-lens collimating lens (1), a first resonance tube (3), a second resonance tube (2), a quartz tuning fork (7), a dual V-shaped groove fixed seat (8) and a substrate (9), wherein a light path emitted from the second c-lens collimating lens (1) reaches the first c-lens collimating lens (4) after passing through the second resonance tube (2), the finger clearance of the quartz tuning fork (7) and the first resonance tube (3). The c-lens collimating lenses are adopted in the gas cell, so that the light beam can completely pass through the resonance tubes and the quartz tuning fork, the loss of the light beam in incidence can be avoided, and the sensitivity of the gas cell can be improved. Meanwhile, by the adoption of the c-lens collimating lenses, collimating focus is not needed between the light source and the gas cell, so that the size of the photo-acoustic spectrum gas detection device is reduced.

The invention belongs to the technical field of inertial navigation, and more particularly relates to a single-axis rotating micro-mechanical inertial navigation modulation method. The invention aims to carry out modulation on micro-mechanical gyroscopic drift by utilizing a low-cost rotating mechanism and improve the pure inertial navigation accuracy of an inertial navigation system. The method comprises the steps of: construction of the single-axis rotating mechanism, initial alignment and navigation calculation for obtaining a pose matrix in a carrier coordinate system; the single-axis rotating mechanism comprises a shaft driven by a driving device; the shaft drives an installation platform to rotate; and the installation platform can be used for installing an inertial measuring unit. According to the method, the equivalent accuracy of a quartz tuning-fork gyroscope can be greatly increased, the pure inertial navigation accuracy of the system is increased to 2nmile / 10min, and the requirement on high-accuracy navigation is met.

A multiple-degree-of-freedom near-field optical microscope based on a micro-nano motion arm comprises the micro-nano motion arm, a quartz tuning fork, a near-field optical probe, a sample scanning stand, a sinusoidal signal generator, a preposed lock-in amplifier, a control box and a detector and / or a light source, wherein the quartz tuning fork is fixed at the front end of the micro-nano motion arm; the near-field optical probe is fixed on one tuning fork arm of the quartz tuning fork; the sample scanning stand is positioned under the quartz tuning fork; the signal output end of the sinusoidal signal generator is connected with the input end of the quartz tuning fork; the input end of the preposed lock-in amplifier is connected with the output end of the quartz tuning fork; the input end of the control box is connected with the output end of the preposed lock-in amplifier, one output end of the control box is connected with the input end of the micro-nano motion arm, and the other output end of the control box is connected with the input end of the sample scanning stand; and the detector and / or the light source are / is connected with the near-field optical probe. The multiple-degree-of-freedom near-field optical microscope has an optical resolution capability beyond the diffraction limit as well as large-scale mobile flexibility and multi-degree-of-freedom operation capability, occupies a small space, and is very convenient to be combined with other microscopic characterization methods.

The invention discloses an imaging system of an atomic force microscope (AFM) on the basis of a quartz tuning fork probe. An AFM controller in the system is respectively connected with a graphic display, a piezoelectric ceramic tube scanner, a drive circuit of a stepping motor, a feedback signal detection circuit and a scanning control signal processing circuit through wire cables so as to achieve transmission of electrical signals, a probe limiting seat is installed on a sample table, a round mounting table is mounted above the probe limiting seat, and the piezoelectric ceramic tube scanner, a displacement adjusting component and a circuit mounting box which is supported by four supporting columns are installed on the round mounting table. By means of the imaging system of the AFM on the basis of the quartz tuning fork probe, a student can know basic working principles of the AFM and operating steps of the imaging system, and the imaging system can be used for observing a microstructure of a sample. During an experiment, the student can measure force sensor--quartz tuning fork probe damping coefficient of the imaging system and observe bistable state phenomena to further understand AFM force action mechanism and parameter setting.

The invention discloses a quartz tuning fork-based nano measuring head, which is characterized in that a quartz tuning fork is adopted as a micro-force sensor for sensing sample micro-topography, a piezoelectric driver is fixed on one tuning fork arm of the quartz tuning fork, and a piezoelectric sensor is fixed on the other tuning fork arm; and the vibration direction of the quartz tuning fork is set to be vertical to the surface of a sample, the tuning fork arm on one side close to the sample is fixedly provided with a tungsten probe vertically pointing to the surface of the sample, a sine alternating-current signal serving as a vibration exciting signal is applied to the piezoelectric driver, and the piezoelectric sensor detects a tuning fork resonance signal. The vibration direction of the tuning fork is vertical to the surface of the sample, so the contact time of the probe and the sample is short, the damage to the sample is little, and the quartz tuning fork-based nano measuring head is particularly suitable for detecting the surface of soft materials with high precision and micro measuring force.

The invention discloses a three-dimensional resonance trigger probe based on a quartz tuning fork and a three-dimensional resonance trigger location method. The three-dimensional resonance trigger probe is characterized in that the quartz tuning fork is used as a micro force sensor, a piezoelectric driver is fixed on a fork arm of the quartz tuning fork, a piezoelectric sensor is fixed on the other fork arm; the quartz tuning fork is vertical to the surface of a sample in the vibration direction on the Z direction and is parallel to the surface of the sample in the vibration direction on X and Y directions, an integrated micro measuring bar measurement ball is fixedly arranged on the fork arm close to one side where the sample is in, and a sine alternating-current signal output by a phase-locked loop is applied to the piezoelectric sensor as an excitation signal, and a fork resonance signal is detected by the piezoelectric sensor. When a micro three-dimensional external force causes that the resonance frequency of the probe changes, the resonance frequency of a quarts tuning fork probe changes, and three-dimensional resonance trigger location of the three-dimensional resonance trigger probe is realized through detecting the change of the resonance frequency of the quartz tuning fork.

The invention provides a two-dimensional force-measuring device based on a two-end-fixed quartz tuning fork and a method thereof. The device comprises a support, a quartz tuning fork, a vibration generator, a measuring probe, a Doppler vibration measuring instrument, a piezoelectric micro-motion experiment table, a first sinusoidal signal generator, a second sinusoidal signal generator, a signal conditioning circuit, a first phase lock amplifier, a second phase lock amplifier, a data acquisition module and a computer. The method comprises the steps of placing a to-be-measured sample on the piezoelectric micro-motion experiment table; adjusting the distance between the piezoelectric micro-motion experiment table and the measuring probe; adjusting the vibration frequency and amplitude of the first sinusoidal signal generator and the second sinusoidal signal generator; continuously adjusting the height of the piezoelectric micro-motion experiment table to make the piezoelectric micro-motion experiment table approach the measuring probe at set speed; recording the vibration amplitude and phase change information by the computer; calculating the axial force Fn and the horizontal shear force FS. The device and the method can realize the two-dimensional force measurement of the axial force and the shear force of liquid phase substances; higher Q values can be obtained and higher sensitivity can be obtained.

The present invention is an optical fiber probe having excellent vibration property and its manufacturing method relating to the scanning optical micro-imaging technology, particularly being directed to the imaging members provided in the scanning type of the near-field optical microscope and their manufacturing method in the near-field optical experiment technology. In this method, the optical fiber probe of prior art is cut off into a shape of short needle to make it face and be coupled with the end face of another long optical fiber connected to an photoelectric detector, said optical fiber short needle being placed on a vibrating arm of a vibrating member (e.g. quartz tuning fork) and said long optical fiber being placed on a fixed arm of the vibrating member; its manufacturing steps comprises preprocessing, marking position, pre-cutting, needle shaping, fixing optical fiber needle, cutting off it into short needle, coupling it with long optical fiber, etc. This invention has the novel structure of non-contacting type of short probe and the basic frequency of the vibrating frequency of the vibrating member is not interfered, so that the optical fiber probe has the excellent vibrating property, and the optical transmitting efficiency is not affected very much, the manufacturing cost is not increased. The invention can be used readily in the current near-field optical microscopes.

The invention provides a Q-switched fiber laser intra-cavity photoacoustic spectrometry gas detection system, and belongs to the technical field of fiber gas detection. The Q-switched fiber laser intra-cavity photoacoustic spectrometry gas detection system comprises a pump light source, a rare earth doped fiber, a Q switch and the like, wherein a ring cavity of a pulse fiber laser is composed of a wavelength division multiplexer, the rare earth doped fiber, an optical isolator, a gas chamber, the Q switch and an optical fiber coupler, and an input coupling mirror and an output coupling mirror are placed in the gas chamber; a quartz tuning fork is placed in the gas chamber and used for detecting sound wave signals, and pulse laser light in the cavity of the fiber laser excites gas to produce the sound wave signals; the signals detected by the quartz tuning fork is extracted by a phase locking amplifier further, and then is obtained and transmitted to a computer through a data acquisition card, and gas concentration information is obtained after gas concentration inversion is conducted. By combining the fiber laser technology and the photoacoustic spectrometry gas detection technology, the Q-switched fiber laser intra-cavity photoacoustic spectrometry gas detection system has the advantages of having high sensitivity, higher cost performance, low cost and the like.

The invention discloses an optical fiber evanescent wave form quartz enhanced photoacoustic spectrum sensor and a gas measurement method. The sensor is composed of a semiconductor laser source, a front single-mode optical fiber, a tapered optical fiber, a quartz tuning fork and a rear single-mode optical fiber, wherein the semiconductor laser source, the front single-mode optical fiber, the tapered optical fiber and the rear single-mode optical fiber are arranged in sequence along a light beam transmission direction; and the tapered optical fiber penetrates through a fork leg of the quartz tuning fork. Semiconductor laser is transmitted to the tapered optical fiber through the front single-mode optical fiber, and an evanescent wave field with strong energy is generated on the tapered optical fiber; gas to be detected absorbs the energy of the evanescent wave field to generate sound waves; and the quartz tuning fork receives a sound wave signal to invert gas concentration. The novel full-optical-fiber evanescent wave form quartz enhanced photoacoustic spectrum sensor is constructed aiming at sensing detection of trace gas; and compared with a traditional lens transmission system, the optical fiber evanescent wave form quartz enhanced photoacoustic spectrum sensor has the extremely low insertion loss, the stability of a sensor system is extremely improved, the structure is simple and the volume is small.

The invention discloses a broadband-spectrum type photoacoustic spectrometric long-distance detection apparatus for trace substances, belonging to the field of spectrometric detection of trace substances. The apparatus comprises an excitation light source, a reflecting object, a concave mirror, a carbon nanotube composite photoacoustic energy transducer, a quartz tuning fork, a coupler, a fiber laser, a photoelectric detector and a data processing system, wherein the excitation light source and the reflecting object are located on a same light path; the concave mirror is arranged on the emergent path of the reflecting object; the carbon nanotube composite photoacoustic energy transducer is located at the focus of the concave mirror; the quartz tuning fork and the end surface of an optical fiber form Fabry-Perot cavity; the coupler is connected with the optical fiber; the fiber laser is connected with the coupler via the optical fiber; and the coupler is successively connected with the photoelectric detector and the data processing system via the optical fiber. The invention also discloses a broadband-spectrum type photoacoustic spectrometric long-distance detection method for trace substances and realizes long-distance detection of a plurality of trace substances.

The invention relates to a high-sensitivity MEMS resonant temperature sensor chip, and belongs to the technical field of MEMS temperature sensors. The chip comprises a quartz glass annular base and aquartz crystal resonance layer, the quartz crystal resonance layer comprises a rhombic force amplification resonator, a first quartz arm, a second quartz arm, a first anchor point and a second anchorpoint; the rhombus force amplification resonator comprises a rhombus ring and a double-end clamped quartz tuning fork; the first anchor point, the first quartz arm, the second quartz arm and the second anchor point are positioned on a short diagonal line of the rhombus ring; and the double-end clamped quartz tuning fork is positioned on the long diagonal line of the rhombus ring. When the temperature of a measured environment changes, the quartz crystal resonance layer generates thermal expansion deformation due to restriction of the annular base, large axial stress is generated in the pair ofquartz arms, and the large axial stress is amplified by the rhombic ring to act on the double-end clamped quartz tuning fork. The sensitivity of the sensor and the stability of the resonance frequency are remarkably improved, and the sensor has the advantages of being simple in structure, high in anti-interference capacity and the like.

The invention discloses a laser power fluctuation monitoring and compensating device and method for photoacoustic spectrum measurement, and belongs to the technical field of photoelectric detection. Two quartz tuning forks are adopted at the same time for measurement; one quartz tuning fork is used for monitoring the fluctuation of the laser power; the other quartz tuning fork is used for measuring photoacoustic spectrum; the influence of the laser power fluctuation to the photoacoustic spectrum measurement is removed by processing the signal output by the quartz tuning fork used for measuring the laser power, and then compensating the measurement result of the photoacoustic spectrum; the fluctuation of the laser power is inhibited. The device is reasonable in design, simple in structure, and easy to realize; the method can monitor the laser power in real time, and compensate the fluctuation of the laser power, so as to inhibit the fluctuation of the laser power; the problem that the photoacoustic spectrum detection is interfered by the fluctuation of the laser power is solved.

A double-tube side-by-side type quartz tuning-fork enhancing type photoacoustic spectrometry detection apparatus comprises a laser, a focusing lens, a collimating lens, a gas sample pool, a lock-in amplifier, a laser controller, a function generator, a control hose, a frequency tracking controller, and a preamplifier electrically connected with a quartz tuning fork output terminal. Two same optical paths are respectively subjected to collimation and focusing, then enter miniature tubes, are focused at the focus at the central parts of the miniature tubes, and respectively generate opto-acoustic signals. The gas sample pool is provided with a mounting base, two miniature tubes are symmetrically arranged at the sidewalls of the mounting base, the quartz tuning fork is arranged at the bottom of the mounting base, and the tuning fork arm of the quartz tuning fork is parallel to or perpendicular to the miniature tubes. The central position of each miniature tube is provided with a slit corresponding to a notch or the tuning fork arm of the quartz tuning fork, and when working, the quartz tuning fork is subjected to the sound pressure effect of the miniature tubes at two sides at the same time, and the signal intensity is enhanced. The apparatus also is provided with a constant-temperature water hole at the bottom of the mounting base for keeping quartz tuning fork properties stable.

The invention discloses a tunable-laser-based quartz tuning fork enhancement type photo-acoustic spectrum distributed optical fiber gas sensor. The tunable-laser-based quartz tuning fork enhancement type photo-acoustic spectrum distributed optical fiber gas sensor comprises a laser source (1), a plurality of sensing units (5) and a phase-locking amplifier (6), wherein the sensing units (5) are cascaded by an optical fiber and distributed in one area; the laser output by the laser source (1) is transmitted to a first-level sensing unit (5) by virtue of a distributed optical fiber (4); the laser output by the first-level sensing unit (5) is used as incident light and enters a second-level sensing unit (5), so the cascading utilization of the laser energy can be achieved in a similar manner; detection signals output by the sensing units (5) are sent to the phase-locking amplifier (6); the output of the phase-locking amplifier (6) is connected with a control terminal (7); and the control terminal (7) is used for displaying and alarming the input detection signals. The tunable-laser-based quartz tuning fork enhancement type photo-acoustic spectrum distributed optical fiber gas sensor is efficient and reliable, and is high in sensitivity and strong in adaptability.

The invention discloses a double-spectrum gas detection device and method based on quartz tuning forks. The double-spectrum gas detection device is characterized by comprising a wavelength tunable laser, a focusing collimating lens, an aperture adjustable diaphragm, a sample cell, a light inlet window piece, a first tuning fork, a gas inlet and outlet, a second tuning fork, a first preamplifier circuit, a second preamplifier circuit, a laser control module, an analog to digital conversion module, a digital to analog conversion module, and a computer control unit. According to the double-spectrum gas detection device disclosed by the invention, the quartz tuning forks are used as an optical signal detector and an acoustic signal detector at the same time due to the resonance characteristicsand the piezoelectric effect of the quartz tuning forks, a double-spectrum technique for simultaneously obtaining a direct absorption spectrum signal and a photoacoustic spectrum signal, correction is provided for the photoacoustic spectrum through the gas concentration information inverted from the direct absorption spectrum signal, the corrected photoacoustic spectrum and the direct absorptionspectrum are respectively applied to low concentration and high concentration sample analysis, and the laser light intensity can be fully utilized to achieve gas concentration measurement of a wide dynamic range.

The invention relates to the structural design of a gas sensing head, and in particular relates to a quartz enhancing photoacoustic spectrophone and an assistant assembling device and an assistant assembling method thereof. The technical problem that the existing quartz enhancing photoacoustic spectrophone is not high in sensitivity and low in assembling efficiency is overcome. The quartz enhancing photoacoustic spectrophone comprises a quartz tuning fork and a pair of miniature sound resonant cavities fitting with the tuning fork, and also comprising a structural support for fixing the quartz tuning fork and the pair of miniature sound resonant cavities, wherein the structural support comprises a cube, the top of the cube is downwards provided with a groove along a central line, the center of the groove is downwards provided with a through hole, and a pair of raised tubular trays with cube structures are formed on two sides of the groove. According to the quartz enhancing photoacoustic spectrophone and the assistant assembling device and method thereof, through designing the assembling technological process and researching the assisting assembling device, assembling efficiency is greatly improved, and the technical problem that the quartz enhancing photoacoustic spectrophone is not high in assembling precision is overcome.

A silicon substrate quartz acceleration sensor with a temperature isolation structure comprises a silicon substrate and a double end fixed quartz tuning fork, wherein a mass block on the silicon substrate is connected with the silicon substrate through two flexible beams, a groove is etched in the portion, on the same side of the flexible beams, of the surface of the silicon substrate, the two ends of the groove are respectively connected with a cavity, on the side of the flexible beams, of the mass block and a cavity below the temperature isolation structure, the temperature isolation structure is composed of a fixing seat and a supporting beam, a supporting seat at one end of the double end fixed quartz tuning fork is fixed on the fixing seat of the temperature isolation structure, a supporting seat at the other end of the double end fixed quartz tuning fork is fixed on the mass block, two fork teeth of the double end fixed quartz tuning fork are connected with the supporting seats through fixing ends, and an electrode is covered on the periphery of the fork teeth. When acceleration has an effect on the sensor, the mass block supported by the flexible beams generates displacement to pull or press the double end fixed quartz tuning fork to change vibration frequency of the double end fixed quartz tuning fork and achieve the measurement of the acceleration by the quartz. The temperature isolation structure of the silicon substrate quartz acceleration sensor can reduce the effect of low temperature on the accuracy of the sensor.

The invention discloses an evanescent-wave type photoacoustic spectrum trace gas sensor based on an optical fiber resonant cavity and a measurement method. The sensor is composed of a semiconductor laser source, an optical fiber combiner, a tapered optical fiber, a quartz tuning fork and a phase modulator. The measurement method comprises the following steps that (1) laser emitted by the semiconductor laser source is input into the optical fiber combiner, and the laser passes through the phase modulator, so that the optical fiber combiner is formed into an optical resonant cavity, and the laser power in optical fiber is amplified and enhanced, therefore a stronger optical evanescent field is generated in the position of the tapered optical fiber; (2) to-be-measured target gas absorbs the energy of an evanescent wave field in the position of the tapered optical fiber, so that an acoustic wave field is generated; the quartz tuning fork is used for detecting an acoustic wave signal and inverting gas concentration. The evanescent-wave type photoacoustic spectrum trace gas sensor based on the optical fiber resonant cavity and the measurement method have the advantages that the laser excitation power is effectively improved, therefore the detection sensitivity of a photoacoustic spectrum gas sensor is greatly improved.

The invention discloses a method for controlling the distance from a needle point of an atomic force microscope to a sample by the aid of a quartz tuning fork and an atomic force microscope system with a quartz tuning fork. The atomic force microscope system is built on the basis of the method, and comprises an atomic force needle (1), a quartz tuning fork detector (2), a quartz tuning fork driving and detecting circuit (3), a three-dimensional sample position controller (4), an atomic force microscope controller (5) and other facilities of an atomic force microscope, and the other facilities of the atomic force microscope include a shock-resistant isolation component, a needle feeding motor controller (6) and the like. The quartz tuning fork driving and detecting circuit (3) comprises a signal source A and a signal source B, the amplitude of the signal source A and the amplitude of the signal source B are identical, the phase position of the signal source A is opposite to the phase position of the signal source B, the frequency and the amplitude of each signal source can be adjusted simultaneously, the signal source B is connected with a capacitor, and the signal source A is connected with the quartz tuning fork detector. The other end of the quartz tuning fork detector is connected with the other end of the capacitor and a resistor, and the other end of the resistor is grounded. Voltage difference between two ends of the resistor is amplified by an amplifier and then is outputted in a phase lock manner.