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

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.

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 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 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 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.

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.