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2436results about How to "Improve fineness" patented technology

Composite wavelength reference-based fiber bragg grating sensing demodulation device and method

The invention discloses a composite wavelength reference-based fiber bragg grating sensing demodulation device and method. The composite wavelength reference-based fiber bragg grating sensing demodulation device includes a broadband light source (1), a tunable FP filter (2), an optical fiber primary beam splitter (3), an optical fiber circulator (4), an optical fiber grating sensing array (5), a first optical fiber secondary beam splitter (61), a second optical fiber secondary beam splitter (62), an optical fiber air chamber (7), an optical fiber FP etalon (8), a notching filter (9), a photoelectric detection array (10), a data acquisition card (11) and a processing unit (12); and the composite wavelength reference-based fiber bragg grating sensing demodulation device further comprises a sensing link and a wavelength reference link. Compared with the prior art, and according to the composite wavelength reference-based fiber bragg grating sensing demodulation device and method of the invention, equal-interval reference wavelengths can be provided by the optical fiber FP etalon, and therefore, advantages of high fineness of transmission peaks, easiness in peak finding and wide wavelength coverage range can be realized; absolute reference wavelengths provided by the optical fiber air chamber are not affected by environmental factors such as temperature, vibration and impact; and stable fiber bragg grating demodulation is realized.
Owner:TIANJIN UNIV

Method for controlling well bore pressure based on model prediction control theory and systems theory

ActiveUS20140262246A1Easy to controlReducing underground complex accidentsSurveyConstructionsPresent methodStart time
A method for controlling well bore pressure based on model prediction control theory and systems theory, which belongs to the field of well bore pressure control technique, includes: detecting a well bottom pressure, a stand pipe pressure, a casing pressure, an injection flow rate and an outlet flow rate during construction process, and determining the presence of overflow or leakage; if there is no overflow or leakage, then fine-adjusting the wellhead casing pressure according to the slight fluctuations of the well bottom pressure, the stand pipe pressure or the casing pressure, ensuring that the well bottom pressure, the stand pipe pressure or the casing pressure are at a set value; if there is overflow or leakage, then using a well bore multi-phase flow dynamic model to simulate and calculate the overflow or leakage position and starting time of the overflow or leakage, predicting the variation over a future time period of the well bore pressure in the well drilling process, and utilizing an optimization algorithm to calculate the control parameter under a minimum of an actual well bottom pressure difference during the future period; and repeating the optimization process for the next time period after a first control parameter is selected and set. The present method enables the well bore pressure to be controlled within the allowable fluctuation range of a project, thus achieving precise pressure control.
Owner:CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD

Method for bus origin-destination (OD) investigation by using mobile phone base station data and operating vehicle global position system (GPS) data

The invention provides a method for bus origin-destination (OD) investigation by using mobile phone base station data and operating vehicle global position system (GPS) data, comprising the following steps: 1) collecting mobile phone positioning data and bus GPS data; 2) transferring the mobile phone positioning data into travel information of users; 3) extracting characteristic values from the travel information of the users; 4) analyzing the extracted characteristic values to obtain basic travel characteristics; 5) matching bus travel information with the bus GPS data to obtain bus travel characteristics; and 6) carrying out statistical process on the obtained travel characteristics, and then outputting a population travel characteristic report form. The method is based on the mobile phone positioning data and the bus GPS data and then is used for performing a series of processes on the mobile phone positioning data and the bus GPS data, thereby automatically obtaining a high-quality, high-fineness and large time-span population travel characteristic reform form from a great amount of data, intelligently acquiring the population travel characteristics, reducing manpower and material resource consumption and improving the accuracy and effectiveness of the investigation.
Owner:广州通易科技有限公司

Miniature F-P (Fabry-Perot) cavity tunable filter and method for manufacturing same

The invention discloses a miniature F-P (Fabry-Perot) cavity tunable filter and a method for manufacturing the same. The miniature F-P cavity tunable filter comprises a substrate. An antireflection film is attached to one surface of the substrate, a first bragg reflector is attached to the other surface of the substrate, and a first electrode and a second electrode are attached onto the first bragg reflector; four metal piers are attached onto the first electrode, and a bridge surface is attached onto the four metal piers; the bridge surface comprises four cantilever beams and a movable diaphragm, each cantilever beam is L-shaped, one end of each cantilever beam is perpendicularly fixedly connected with the corresponding metal pier, and the other end of each cantilever beam is connected with the movable diaphragm; the movable diaphragm is square, and a second bragg reflector is inlaid in the center of the movable diaphragm; the first bragg reflector and the second bragg reflector form a resonant cavity of an F-P cavity; after the miniature F-P cavity tunable filter is powered on, the four cantilever beams elastically deform and can drive the movable diaphragm and the second bragg reflector to move in the direction perpendicular to the first bragg reflector, so that the length of the resonant cavity is changed, and a tunable function of the filter is realized. The miniature F-P cavity tunable filter and the method have the advantage that the filter is wide in tunable range and high in response speed.
Owner:HUAZHONG UNIV OF SCI & TECH +2
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