30results about How to "Eliminate cross-sensitivity" patented technology

The invention discloses an orthogonal polarization optical fiber biological refractive index sensor and a detecting method thereof. The refractive index sensor includes a broadband light source, a polarizer, a polarization controller, a sensor probe and an orthogonal polarization demodulation processing unit which are sequentially connected with one another by optical fibers; the sensor probe includes a microfluidic control chip for control of injection and discharge of a trace biological solution, and tilted optical fiber optical gratings arranged in microfluidic channels of the microfluidic control chip; the orthogonal polarization demodulation processing unit includes an optical fiber polarization beam splitter, a first spectral detector, a second spectral detector and a spectrum differential module; the sensor probe is connected with the input ends of the first spectral detector and the second spectral detector through the optical fiber polarization beam splitter, and the output ends of the first spectral detector and the second spectral detector are connected with the spectrum differential module. The refractive index sensor has the advantages of high measuring precision of the refractive index, and can realize simultaneous measurement of environmental temperatures.

A volumetric flow of an analyte, including exhaled air, is fed to a gas sensor unit by used of gas flow device, which can include various sensors for the determination of nitrogen oxides. An oxidation catalyst is used when using an NO2 sensor, which converts nitrogen monoxide to nitrogen dioxide and the gas sensor unit measures the content of nitrogen dioxide. The nitrogen monoxide content is calculated from the nitrogen dioxide content. In order to eliminate cross-sensitivity moisture and ethanol are also measured. The device can be applied to the determination of nitrogen monoxide content of exhaled air.

Belonging to the field of measurement technologies, the invention relates to a fiber bragg grating based composite material thermal expansion coefficient measuring device and a measuring method. The device comprises a fixture (5), a standard test block (7), a composite material block to be measured (6) and a fiber bragg grating sensor (8). Specifically, one end of the fiber bragg grating sensor (8) is fixed with a free end of the standard test block (7), and the other end is fixed with the free end of the composite material block to be measured (6). The fiber bragg grating sensor, the composite material block to be measured, and the standard test block are placed in a temperature control box. The composite material block to be measured and the standard test block can expand after being heated, and their different change degrees can generate a pull effect on the fiber bragg grating sensor and cause changes of a grating central wavelength. By combining the fiber bragg grating strain sensitivity and a relative measurement method, accurate measurement of the thermal expansion coefficient in different length sections of a composite material can be realized.

The invention provides a fiber bragg grating type sensing system and a fiber bragg grating type sensing method for simultaneous measurement of temperature and strain. The fiber bragg grating type sensing system comprises a detection light branch circuit, a feedback detection branch circuit, a polarization-maintaining optical coupler, a modulation unit and a calculation unit, wherein the detection light branch circuit outputs double-sideband intensity-modulated detection light which is input to a sensing grating so as to achieve detection of transmission peak centers on a fast axis and a slow axis of the sensing grating; a reflection signal of the sensing grating is input to the feedback detection branch circuit through the polarization-maintaining optical coupler; the modulation unit outputs a frequency signal to the detection light branch circuit according to a control instruction and reading of the calculation unit; and the calculation unit corrects frequency parameters of the modulation unit according to data provided by the feedback detection branch circuit, so as to lock two sidebands of the detection light on corresponding transmission peaks of the sensing grating and calculates to obtain the temperature and the strain. The fiber bragg grating type sensing system and the fiber bragg grating type sensing method can significantly increase sampling rate and measurement resolution of the temperature and the strain, and achieve higher demodulation precision.

The invention discloses a coupling refractive index meter for an evanescent field among optical fibers and a detecting method of the coupling refractive index meter. The coupling refractive index meter comprises a light source, an optical fiber sensor probe, an optical fiber coupler / circulator, a first photoelectric detector, a second photoelectric detector and a data collecting and processing module, wherein the optical fiber sensor probe comprises an optical fiber engraved with inclined optical fiber gratings and a D-type optical fiber which are parallelly arranged and tightly closed; the light source is connected with one end of the optical fiber engraved with the inclined optical fiber gratings through the optical fiber coupler / circulator; the optical fiber engraved with the inclined optical fiber gratings is connected with the input end of the second photoelectric detector through the optical fiber coupler / circulator; one end of the D-type optical fiber is connected with the input end of the first photoelectric detector through a single mode optical fiber; one end, connected with the optical fiber coupler / circulator, of the optical fiber engraved with the inclined optical fiber gratings and one end, connected with the first photoelectric detector, of the D-type optical fiber are on the same side; the first photoelectric detector and the second photoelectric detector are separately connected with the data collecting and processing module. The coupling refractive index meter has the advantage of being higher in refractive index measuring accuracy.

The invention provides a fiber grating differential strain gauge. The fiber grating differential strain gauge comprises a first fiber grating, a second fiber grating, an elastomer and installation arms, wherein the elastomer is a deformable body which is hollow and is in axial symmetry and central symmetry, the two ends of the first fiber grating are bonded to one side of the elastomer, the two ends of the second fiber grating are bonded to the other side of the elastomer, the first fiber grating and the second fiber grating are perpendicular to each other, grating bodies of the fiber gratings penetrate through the center of the elastomer and do not make contact with each other, the installation arms are fixed to the two sides of the elastomer, the installation arms and the first fiber grating are arranged in the same direction, the thickness of each installation arm is larger than that of the elastomer, and open grooves which penetrate through a tail fiber of the first fiber grating are formed in the installation arms. According to the fiber grating differential strain gauge, the two-end bonding mode is adopted for the structure, it is ensured that stress of grating parts is uniform, the chirp phenomenon is eliminated, detection accuracy is ensured, a manufacturing process of the fiber grating differential strain gauge can be simpler through the two-end bonding mode, and operation is easier.

A FET gas sensor having a relatively low operating temperature, for example, room temperature, is free from cross sensitivities from interfering gases by a preceding in-line filter. The sensor's service life is substantially stabilizable by using fabric-like activated charcoal filters which can be regenerated by a moderate temperature increase, and by limiting the diffusion of the analyte gas, which is made possible by the relatively small amount of gas detectable on the sensitive layer of the sensor. This substantially increases the service life of the filters. The gas sensor eliminates cross sensitivities to thereby increase the detection reliability thereof. Also, the gas sensor has relative long term stability and is economical to build. The gas sensor can read relatively weak signals generated by gas-sensitive layers, for example, without other stronger gas signals interfering with the weak signals.

A wearable sensor badge utilizes a carbon nanotube (CNT) sensor array for selective sensing of chemicals from naturally diffused air or by sampling air using a pump / fan for higher sensitivity. An embedded microcontroller monitors the resistance of the sensing elements and by using an advanced detection algorithm the presence of TICs and / or CWAs are identified.

The invention discloses a plasma resonance tilted fiber Bragg grating hydrogen sensor, a plasma resonance tilted fiber Bragg grating hydrogen detection system and a plasma resonance tilted fiber Bragg grating hydrogen method. The system comprises a light source, a polarizer, a polarization controller, a plasma resonance tilted fiber Bragg grating hydrogen sensor, a photoelectric detector, an oscilloscope and a gas storage container; the light source, the polarizer, the polarization controller, the hydrogen sensor, the photoelectric detector and the oscilloscope are sequentially connected with one another; the hydrogen sensor is arranged in the gas storage container when hydrogen is measured; the hydrogen sensor comprises an optical fiber engraved with a tilted fiber Bragg grating; the tilt angle of the tilted fiber Bragg grating is smaller than or equal to 45 degrees; the outer surface of the cladding layer of the optical fiber is plated with a nano-scale palladium film; plasma resonance waves on the surface of the palladium film are excited through the tilted fiber Bragg grating plated with the palladium film, so that specific recognition is carried out on the hydrogen; and the high-precision measurement of the static concentration and dynamic concentration change of the hydrogen is further realized.

The invention discloses an intelligent method for inhibiting cross sensitivity of gas sensor, which uses intrinsic gas characteristic spectrum amplitude as the input vector of neural network, calculates via an artificial neural network based on a neural network structure marked and trained via standard gas to further eliminate the cross sensitivity of gas sensor caused by laminated frequency to obtain single gas content and improve inhibit effect, thereby improving gas detection precision and accuracy. The invention uses wavelet analysis to input characteristic vector to the artificial neutral network and uses the localization ability of wavelet analysis in time and frequency domains, to analyze characteristic gas response waveform and cross sensitive gas response waveform, to further improving the inhibition effect and improving gas detection precision and accuracy.

The invention discloses a multi-gas sensing device, using the planar waveguide circuit to construct the multi-gas sensing platform with sensing channel and reference channel, substantially thin gas sensor structure, to increase gas sensor accuracy and long-term stability, and reduce the response time. It can be widely used in factory work site's safety monitoring, staff security monitoring, factory disaster warning, restricted regional security monitoring, pipeline leak investigation, environmental steam locomotive emission monitoring, and home environment quality monitoring.

The invention relates to an intensity detection type photonic crystal fiber long period grating stress sensor based on waveguide array grating differential demodulation. Two ports of the photonic crystal fiber long period grating are respectively optically connected to incidence ends of a broadband light source and the waveguide array grating. A second channel and an eighth channel of the waveguide array grating are two outgoing ends optically connected to a photoelectric converter and a signal processing unit. The photonic crystal fiber long period grating is a sensing element; and the waveguide array grating, the photoelectric converter and the signal processing unit form a demodulator of the optical fiber sensor. Through the sensor and the device, the interference brought by dithering of the light source and various instability factors of a sensing system is effectively eliminated, and the accuracy of the system is greatly improved.

The invention relates to a HiBi-PCF-FLM (fiber loop mirrors made of highly birefringent photonic crystal fiber) stress sensor based on strength detection differential demodulation and a device. In the invention, two ports on one side of a 3dB coupler are respectively optically connected with a wideband light source and the incident end of a wavelength division multiplexer; two ports on the other side of the 3dB coupler are respectively optically connected with both ends of a HiBi-PCF (highly birefringent photonic crystal fiber); and the fifth channel and the sixteenth channel of the wavelength division multiplexer are two emergent ports which are optically connected with a photoelectric converter and a signal processing unit. The 3dB coupler and the HiBi-PCF form the sensing element of the HiBi-PCF-FLM; and the wavelength division multiplexer, the photoelectric converter and the signal processing unit constitute the demodulator of the optical fiber sensor. The HiBi-PCF-FLM stress sensor can eliminate the interferences caused by the light source jitter and various kinds of unstable factors of the sensing system, thereby greatly improving the system accuracy.

The present invention provides an inductance magnetic sensor for inhibiting direction crosstalk and a preparation method thereof. The sensor comprises an insulation non-conductive magnet substrate, a sensing coil, a bias coil, insulation layers and a permeability magnetic material layer. The sensing coil is located on the insulation non-conductive magnet substrate, the bias coil is located between the two insulation layers and is partly overlapped with the sensing coil, and the permeability magnetic material layer is located the uppermost insulation layer. The inductance magnetic sensor for inhibiting direction crosstalk and the preparation method thereof can inhibit the inter-axis crosstalk of the sensor, eliminate inter-axis cross sensitivity and improve the sensing performance of the magnetic sensor.

The invention provides a fiber grating differential strain gauge. The fiber grating differential strain gauge comprises a first fiber grating, a second fiber grating, an elastomer and installation arms, wherein the elastomer is a deformable body which is hollow and is in axial symmetry and central symmetry, the two ends of the first fiber grating are bonded to one side of the elastomer, the two ends of the second fiber grating are bonded to the other side of the elastomer, the first fiber grating and the second fiber grating are perpendicular to each other, grating bodies of the fiber gratings penetrate through the center of the elastomer and do not make contact with each other, the installation arms are fixed to the two sides of the elastomer, the installation arms and the first fiber grating are arranged in the same direction, the thickness of each installation arm is larger than that of the elastomer, and open grooves which penetrate through a tail fiber of the first fiber grating are formed in the installation arms. According to the fiber grating differential strain gauge, the two-end bonding mode is adopted for the structure, it is ensured that stress of grating parts is uniform, the chirp phenomenon is eliminated, detection accuracy is ensured, a manufacturing process of the fiber grating differential strain gauge can be simpler through the two-end bonding mode, and operation is easier.

A hydrogen gas sensor (1) for online monitoring of the hydrogen gas concentration in an oil-immersed transformer and a method for using same. The sensor (1) comprises a hydrogen gas sensitive probe (2), the hydrogen gas sensitive probe (2) comprises a hydrogen gas sensitive chip (5) in direct contact with transformer oil (16), the hydrogen gas sensitive chip (5) comprises a substrate, an electrical insulating layer arranged on the substrate and a hydrogen gas sensitive element arranged on the electrical insulating layer, and a hydrogen gas specificity coating for inhibiting the diffusion of gas molecules other than hydrogen gas is arranged on the surface of the hydrogen gas sensitive element. The sensor (1) can be in direct contact with the transformer oil (16), so that an oil-gas separation device is avoided, the reliability of the sensor (1) is improved, and the maintenance cost is lowered; and on the other hand, use of the hydrogen gas specificity coating eliminates cross responses of the sensor (1) to fault gases such as CO, C2H2 and C2H4, and the hydrogen gas concentration and the rate of change thereof in the transformer oil (16) can be monitored in a continuous and reliable way, and a dependable basis for learning the operating condition of the transformer (15) accurately is offered.

The invention discloses an orthogonal polarization optical fiber biological refractive index sensor and a detecting method thereof. The refractive index sensor includes a broadband light source, a polarizer, a polarization controller, a sensor probe and an orthogonal polarization demodulation processing unit which are sequentially connected with one another by optical fibers; the sensor probe includes a microfluidic control chip for control of injection and discharge of a trace biological solution, and tilted optical fiber optical gratings arranged in microfluidic channels of the microfluidic control chip; the orthogonal polarization demodulation processing unit includes an optical fiber polarization beam splitter, a first spectral detector, a second spectral detector and a spectrum differential module; the sensor probe is connected with the input ends of the first spectral detector and the second spectral detector through the optical fiber polarization beam splitter, and the output ends of the first spectral detector and the second spectral detector are connected with the spectrum differential module. The refractive index sensor has the advantages of high measuring precision of the refractive index, and can realize simultaneous measurement of environmental temperatures.

A disclosed quasi-reciprocal reflection type optical fiber temperature sensor is characterized by comprising an ASE light source, the ASE light source is connected with a circulator, the circulator is connected with a polarizer and a PIN photoelectric detector, the polarizer is connected with a temperature sensing unit, the PIN photoelectric detector is connected with a digital signal processor, and the digital signal processor is connected with a signal output and control interface; and a temperature sensing unit comprises a sensing optical fiber and a compensation optical fiber, the two ends of the compensation optical fiber are connected with the polarizer and the sensing optical fiber respectively, and the tail end of the sensing optical fiber is plated with a reflecting film. The temperature sensor is composed of an all-fiber structure, coating of metal materials is not needed, partial discharge does not exist, the sensitivity of the temperature sensor can be improved, the temperature sensing part is of a reciprocal structure, the high-birefringence photonic crystal fiber serves as a sensing fiber, the external interference resistance is high, and the sensitivity is high.

The invention discloses an optical fiber inter-fiber evanescent field coupling refractometer and a detection method thereof, comprising a light source, an optical fiber sensor probe, an optical fiber coupler / circulator, a first photodetector, a second photodetector and data acquisition And the processing module; the fiber optic sensor probe includes the optical fiber and the D-type fiber that are arranged in parallel and closely attached to each other. The optical fiber of the fiber grating is connected to the input end of the second photodetector through a fiber coupler / circulator, and one end of the D-type fiber is connected to the input end of the first photodetector through a single-mode optical fiber, and the optical fiber engraved with a tilted optical fiber grating is coupled with the optical fiber One end connected to the device / circulator is on the same side as the end connected to the D-type optical fiber and the first photodetector; the first photodetector and the second photodetector are respectively connected to the data acquisition and processing module. It has the advantage of higher measurement accuracy of the refractive index.

The invention discloses a resonant accelerometer structure with low temperature sensitivity, wherein the resonant accelerometer structure comprises a silicon structure layer; the silicon structure layer comprises a sensitive mass block, first-stage lever amplification mechanisms, direction limiting mechanisms and two double-end fixed tuning fork resonators, and the two double-end fixed tuning fork resonators are adjacently arranged; and one end of each double-end fixed tuning fork resonator is connected with one first-stage lever amplification mechanism through one direction limiting mechanism, the other end of each double-end fixed tuning fork resonator is connected with one resonator anchor point through one direction limiting mechanism, the sensitive mass block is connected with fixed frames through the supporting folding beams, and an integral structure anchor point is arranged between each two fixed frames. The first-stage lever amplification mechanisms connected with the two double-end fixed tuning fork resonators are in two different forms and are symmetrically arranged to form differential output of an accelerometer. According to the invention, the cross sensitivity of acceleration signals can be eliminated, the frequency drift of the accelerometer caused by working temperature change is reduced or even eliminated, and the temperature performance of the accelerometer is improved.

The invention discloses a triangular encapsulation method of a fiber grating sensor, which comprises the steps of: selecting a triangular encapsulation structure and a triangular encapsulation structure material, wherein the triangular encapsulation structure comprises a fiber grating sensor, a slide block, blockers, a rotating shaft, an arm, an arm, an arm and a peripheral encapsulation, the two ends of the fiber grating sensor are annularly adhered by an adhesive, an optical fiber part is adhered by the slide block with one smooth surface on the periphery of the fiber grating sensor, the blockers are connected on the upper surface of the slide block, the lower surface of the slide block is arranged in a ditch groove on the peripheral encapsulation, the blockers on the two ends of the fiber grating sensor are respectively connected with one ends of the arm and the arm, and the other ends of the arm and the arm are connected on a movable rotating shaft, the whole rotating shaft is fixed on one end of the arm, the other end of the arm is fixed on the peripheral encapsulation, and the arm, the arm and the fiber grating sensor form a triangular encapsulation; and the arms are made from the same material. The structure and material selection in the invention greatly improve the sensitivity of the fiber grating sensor.

Belonging to the field of measurement technologies, the invention relates to a fiber bragg grating based composite material thermal expansion coefficient measuring device and a measuring method. The device comprises a fixture (5), a standard test block (7), a composite material block to be measured (6) and a fiber bragg grating sensor (8). Specifically, one end of the fiber bragg grating sensor (8) is fixed with a free end of the standard test block (7), and the other end is fixed with the free end of the composite material block to be measured (6). The fiber bragg grating sensor, the composite material block to be measured, and the standard test block are placed in a temperature control box. The composite material block to be measured and the standard test block can expand after being heated, and their different change degrees can generate a pull effect on the fiber bragg grating sensor and cause changes of a grating central wavelength. By combining the fiber bragg grating strain sensitivity and a relative measurement method, accurate measurement of the thermal expansion coefficient in different length sections of a composite material can be realized.

The present invention discloses a distributed device for simultaneously measuring strain and temperature based on optical frequency domain reflection, comprising a tunable laser, a 1:99 beam splitter, a main interferometer system, a light source phase monitoring system based on an auxiliary interferometer, an acquisition device and a computer processing unit, wherein the main interferometer system comprises two Mach-Zehnder interferometers, and two optical fibers having different cladding diameters are arranged in parallel as sensing fibers. Due to the difference in temperature and strain coefficients of optical fibers of the same diameter, the temperature and strain values during changing the temperature and strain simultaneously can be obtained by matrix operation, thereby achieving an effect of eliminating cross sensitivity of temperature and strain sensing in optical frequency domain reflection.

The invention discloses a time division and frequency division multiplexing rotor type micro-gyro detector which belongs to the field of MEMS (Micro Electro Mechanical Systems) components and aims to solve the problems of two existing differential capacity detection methods. The time division and frequency division multiplexing rotor type micro-gyro detector comprises a rotor type micro-gyro sensing unit, a charge voltage conversion unit, a phase-sensitive demodulating unit, an analog-digital conversion unit, a signal processing unit, a digital-analog conversion unit, a first low voltage and high voltage conversion unit, a second low voltage and high voltage conversion unit and two time division and frequency division multiplexing units, wherein carrier wave excitation signals V+ and V- of the two time division and frequency division multiplexing units and a feedback control signal are multiplexed and loaded to the rotor type micro-gyro sensing unit; an equivalent gyro signal output end of the rotor type micro-gyro sensing unit is connected with the input end of the phase-sensitive demodulating unit; a demodulation signal output end of the phase-sensitive demodulating unit is used for outputting a detection signal and connected with an analog signal input end of the analog-digital conversion unit; subsequently, analog to digital conversion, signal processing, digital to analog conversion and low voltage to high voltage transformation are performed, and then results are fed back to the two time division and frequency division multiplexing units.

The invention provides a wedge-shaped microhole optical fiber grating that can simultaneously measure seawater temperature, salinity and pressure. The microhole optical fiber has multiple microhole structures symmetrically distributed around the fiber core; one of the microhole structures on the outer wall is accurately destroyed. A wedge-shaped structure is formed; the opening angle of the wedge-shaped structure is equal to the internal angle of the micropore θ1 = 45°~55°; the wedge-shaped structure and the surface of the micropore are coated with Au film, which is completed by the chemical plating method to form the SPR sensing required for sensing. area, the film thickness remains consistent everywhere, and the suitable Au film thickness D1=20~40nm; the microporous structure is filled with sensitive material (PDMS) with high thermo-optical coefficient after coating; the wedge-shaped structure is along the axial direction of the fiber core Closest to the core of the fiber, a grating region that can produce periodic refractive index modulation at the core is formed by using fiber writing technology. This structure can better solve the problem of cross-sensitivity of three parameters and achieve high-sensitivity measurement. Its highly integrated and integrated design has strong stability and great potential for sensing applications.

The invention provides a fiber bragg grating type sensing system and a fiber bragg grating type sensing method for simultaneous measurement of temperature and strain. The fiber bragg grating type sensing system comprises a detection light branch circuit, a feedback detection branch circuit, a polarization-maintaining optical coupler, a modulation unit and a calculation unit, wherein the detection light branch circuit outputs double-sideband intensity-modulated detection light which is input to a sensing grating so as to achieve detection of transmission peak centers on a fast axis and a slow axis of the sensing grating; a reflection signal of the sensing grating is input to the feedback detection branch circuit through the polarization-maintaining optical coupler; the modulation unit outputs a frequency signal to the detection light branch circuit according to a control instruction and reading of the calculation unit; and the calculation unit corrects frequency parameters of the modulation unit according to data provided by the feedback detection branch circuit, so as to lock two sidebands of the detection light on corresponding transmission peaks of the sensing grating and calculates to obtain the temperature and the strain. The fiber bragg grating type sensing system and the fiber bragg grating type sensing method can significantly increase sampling rate and measurement resolution of the temperature and the strain, and achieve higher demodulation precision.