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

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.

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 discloses a plasma resonance inclined fiber bragg grating sensor and a detection system and method. The system comprises a light source, a polarizer, a polarizing controller, a plasma resonance inclined fiber bragg grating sensor, a photoelectric detector, an oscilloscope and a sound field signal source. The light source, the polarizer, the plasma resonance inclined fiber bragg grating sensor, the photoelectric detector and the oscilloscope are successively connected. The sensor comprises an optical fiber engraved with an inclined fiber bragg grating, a nanometer level metal film is plated to the outer surface of the optical fiber coating, the angle of the inclined fiber bragg grating is greater than 30 degrees, and a lot of pectiniform cladding modes with effective refractive index coverage of 0.9-1.45RIU and corresponding plasma resonance wave excitation. The system can realize dynamic and static high-precision detection of various media of covered gas and liquids and the refractive index measuring precision can reach 10<-8>RIU.

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 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 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 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 type micropore fiber grating capable of measuring the a mtemperature, salinity and pressure of seawater simultaneously. A micropore fiber internally includes micropore structures distributed around a fiber core symmetrically; one micreopore structure whose outer wall is damaged accurately forms a wedge type structure; an open angle of the wedge type structure equalsthe internal angle theta1=45-55 degree of the micropore; the surfaces of the wedge type structure and the micropore is plated with an Au film by chemical plating, an SPR sensing area required by sensing is formed, the film thickness is kept consistent everywhere, and the proper film D1=20-40nm of the Au film; the micropore structure is filled with a sensitive material PDMS of high thermal-opticalcoefficient after film plating; and the wedge type structure forms a grating region, which can generate periodic refractive index modulation in the fiber core, at the position clearest to the fiber core along the axial direction of the fiber core via a fiber etching technology. The structure solves the problem that three parameters are sensitive to one another, and high-sensitivity measurement isrealized. The highly-integrated design is highly stable, and has high potentials in sensing application.

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.