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3977results about How to "Improve measurement accuracy" patented technology

Resolving power measuring device and resolving power evaluation method for three-generation dim light image intensifier

The invention discloses a resolving power measuring device and a resolving power evaluation method for a three-generation dim light image intensifier, and belongs to the field of optical measurement and metering. The resolving power measuring device is characterized by consisting of a light source component, a resolving power target, a collimator tube, an imaging objective lens, a test camera obscura, a charge coupled device (CCD) camera and a computer. The resolving power evaluation method comprises the following steps of: imaging the resolving power target irradiated by a standard light source to a fluorescent screen by using a measured image intensifier; converting into a frame image of a target line by using the CCD camera, and transmitting into the computer; successively processing asingle frame image of the target line by using a normalized cross correlation model and an optical modulation degree model through internal image processing software of the computer to acquire a single frame processing result; and analyzing multi-frame processing results and performing corresponding supplement operation to acquire a final resolving power evaluation result. By the device and the method, the problem of objective evaluation during resolving power measurement of the three-generation dim light image intensifier is solved; and the device and the method can be popularized to other measurement fields such as an intensified charge coupled device (ICCD) measurement field and the like where resolving power is required to be objectively evaluated, and have wide application prospects.
Owner:CHINA NORTH IND NO 205 RES INST

Multi-position strapping north-seeking system direction effect calibration method

The invention belongs to a calibration method of an error which is measured by a multi-position strapdown north seeking device, in particular to a calibration method of orientation effect of a multi-position strapdown north seeking device. A true north prism, two theodolites and a mechanical dividing rotating platform are used as auxiliary testing tools, the multi-position strapdown north seeking device is fixed on the mechanical dividing rotating platform, and is divided according to one circle equipartition point, an angle of a benchmark prism of a strapdown north seeking system and the true north direction is defined through rotating an equipartition angle value at one time by the mechanical rotating platform and through the true north prism system in an initial rotating position of the north seeking system, and then the angle is compared with a north-oriented value which is measured by the strapdown north seeking system, the error is calculated, and an azimuthal effect of a gyroscope which is simulated according to the characteristic of the error is marked. The invention effectively eliminates measuring error which is caused by the azimuthal effect, thereby improves the measuring accuracy of the multi-position strapdown north seeking system.
Owner:CHANGCHUN INST OF OPTICS FINE MECHANICS & PHYSICS CHINESE ACAD OF SCI

Plate clamper platform for falling weight impact test, and impact speed measurement method

The invention discloses a plate clamper platform for a falling weight impact test, and an impact speed measurement method. The plate clamper platform comprises a clamper structure, a supporting lifting structure and a laser sensor, wherein the clamper structure comprises a plate clamping device, a multi-angle rotation device and a clamper bottom plate, the multi-angle rotation device comprises wall plates, wall plate bolts and a bottom plate bolt, each wall plate is provided with a central hole and two arc-shaped grooves, the two arc-shaped grooves are symmetrically arranged relative to the central hole, clamping plates can rotate along the arc-shaped grooves after the wall plate bolts are completely loosened, the supporting lifting structure comprises a platform and a lifting driving device, the clamper bottom plate can rotate by adopting the bottom plate bolt as the center and can slidably move along a straight strip hole, and the laser sensor is arranged below the weight tray positioned on the periphery of a hammer head. With the plate clamper platform and the impact speed measurement method of the present invention, the composite material plate specimen can be tightly clamped, the multi-angle impact on the specimen can be achieved, and the speed change during the drop hammer falling and impact process can be real-timely measured.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Time difference type ultrasonic flowmeter measuring method based on zero point analysis

The invention discloses a time difference type ultrasonic flowmeter measuring method based on zero point analysis. The time difference type ultrasonic flowmeter measuring method based on zero point analysis is a method for accurately determining fair-current transmission time and countercurrent transmission time through a zero point analysis method. The time difference type ultrasonic flowmeter measuring method based on zero point analysis comprises the steps that (1) after a pulse drive signal is sent out, an A/D converter is started to conduct data collection; (2) a zero point value is searched; (3) whether a zero point is an ultrasonic signal zero crossing point or not is judged; (4) a first zero crossing point in an ultrasonic receiving signal is selected so that the ultrasonic signal arriving time can be determined and the fair-current transmission time and the countercurrent transmission time can be calculated; (5) instant flow of a section to be measured is calculated through the fair-current transmission time and the countercurrent transmission time. The zero point of the ultrasonic signal is not influenced by the external environment, the zero point can be detected even under the conditions that the signal is weak, fluctuation is large and interference is strong, the fair-current transmission time and the countercurrent transmission time of the ultrasonic signal in fluid can be accurately measured, the measuring accuracy of a time difference type ultrasonic flowmeter is greatly improved, and the problems brought by an existing threshold value comparing method are thoroughly solved.
Owner:STATE GRID CORP OF CHINA +2

Dual-detector segmenting gamma-scanning measuring device and scanning method thereof

The invention relates to a dual-detector segmenting gamma-scanning measuring device based on equivalent radius correction, belonging to the technical field of nuclear radiation measurement. The dual-detector segmenting gamma-scanning measuring device comprises a rotary table, a detector platform assembly, a transmission source platform assembly, a platform lifting and driving assembly, two same high-purity germanium detectors, a transmission source, a shielding part of the transmission source and an analysis module, wherein the two same high-purity germanium detectors are provided with collimators. In the invention, the influence of the nonuniformity of materials inside a wastebin is reduced through the constant rotation of the wastebin, layered measurement is carried out on the wastebin undergoing the constant rotation by placing the two same high-purity germanium detectors on different horizontal positions, the radial equivalent radius of each radionuclide layer is obtained through analysis, and the radionuclide activity of the radionuclide layer is accurately computed according to the detection efficient of the radial equivalent radius. Because an assumption of uniform radionuclide distribution is eliminated, the characteristics of an actual wastebin are better accorded with so that the measurement accuracy of the traditional segmenting gamma-scanning technology is greatly enhanced.
Owner:SHANGHAI JIAO TONG UNIV

Grinding wheel external circle run-out detection method based on laser displacement sensor

ActiveCN104990503AEfficient and accurate displayAchieve normal displayUsing optical meansEngineeringComputer software
The invention relates to a grinding wheel external circle run-out detection method based on a laser displacement sensor. The grinding wheel external circle run-out detection method comprises the detecting step of: firstly, installing the laser displacement sensor in front of the external circle surface of a detected grinding wheel, and connecting circuits of detection equipment; determining a signal sampling frequency and a sampling length of each measurement of the laser displacement sensor according to measurement conditions of the detected grinding wheel; setting the signal sampling frequency fk and the sampling length Ls of the laser displacement sensor through computer software; inputting the signal sampling frequency fk and the sampling length Ls into a controller of the laser displacement sensor; and detecting the external circle surface of the detected grinding wheel by using the laser displacement sensor during the rotation of the detected grinding wheel, sampling data and transmitting the data to a computer, and processing and analyzing the sampled data to obtain an external circle run-out value of the detected grinding wheel finally. The grinding wheel external circle run-out detection method based on the laser displacement sensor achieves the real-time and precise measurement of radial run-out of the external circle of the grinding wheel.
Owner:ZHENGZHOU RES INST FOR ABRASIVES & GRINDING CO LTD

Method and apparatus of measuring weak magnetic field strength based on EIT

The invention provides a magnetic measurement apparatus based on atomic quantum effects, which is different from a present apparatus of measuring magnetic field strength. The method and apparatus of the invention utilize the energy level fission of high excitation state atoms caused by the Zeeman effect under the effect of a weak external magnetic field, and accurately controls the excitation frequency of an ultra-narrow line width laser to measure the spectral signal division based on EIT under the magnetic field effect. The intensity of a magnetic field to be measured can be calculated according to a division width. The multiple fission of the atomic magnetic energy level caused by the weak magnetic field Zeeman effect is linear, and accordingly, through fitting measurement results of widths of a plurality of division peak values, the self calibration of the intensity of the measured magnetic field can be realized. The new magnetometer can realize magnetic field intensity measurement with the sensitivity less than 0.1 T, and effectively improve the measurement precision with the further compression of a laser frequency line width. Moreover, the measured magnetic field strength can be effectively traced to an atom transition frequency, and excellent measurement accuracy and self-calibration can be realized.
Owner:SHANXI UNIV

Method for measuring gas hydrate phase balance condition

The invention provides a method for determining the phase balance condition of gas hydrates, which mainly has the procedures: gas to be measured is caused to generate hydrates in a reaction kettle which is provided with a temperature measurement system, a pressure measurement system and an exhaust system; gas-phase space in the reaction kettle is compressed; system temperature in the reaction kettle is regulated to the temperature of the phase balance condition to be measured to exhaust the gas and lower the pressure, as well as the exhaust system is closed when the pressure in the reaction kettle rises at once because the exhaust is stopped, thus the reaction kettle is caused to become a closed system; the variation of the pressure in the reaction kettle is observed, if the pressure keeps invariant for a long time, three-phase balance is considered to be reached, at this time, the corresponding temperature and the corresponding pressure are a set of phase balance condition for the hydrates. The system temperature can further rise to the next balance temperature to be measured, the pressure variation is continuously recorded until the hydrates in the reaction kettle is completely decomposed, therefore, a series of phase balance condition data of the hydrates can be obtained. Adopting the method, the phase balance condition of the gas hydrates in a free water system or a porous media can be measured, and the measurement accuracy is high.
Owner:CHINA UNIV OF PETROLEUM (BEIJING)

Global navigation satellite system receiver and position measurement method

ActiveCN102540200AReduce volumeSame latitude and longitude coordinatesSatellite radio beaconingLaser rangingMaser
The invention discloses a global navigation satellite system (GNSS) receiver and a position measurement method. The GNSS receiver comprises a satellite receiving antenna, a laser ranging instrument, a posture sensor and a maser control board, wherein the posture sensor is used for receiving an azimuth angle, a pitch angle and a roll angle of the satellite receiving antenna. The maser control board is used for obtaining a longitude and latitude coordinate and an elevation coordinate of the phase center of the satellite receiving antenna, transforming the longitude and latitude coordinate and the elevation coordinate into a right-angle coordinate under a local coordinate system SG, obtaining coordinate offset of a measured point and the phase center according to the distance, the azimuth angle, the pitch angle and the roll angle between the satellite receiving antenna and the measured point, and calculating the right-angle coordinate of the measured point under local coordinate system SG. Compared with the prior art, the GNSS receiver improves accuracy of measurement, eliminates a centering rod simultaneously, and reduces the volume. In addition, during measurement, the longitude and latitude coordinate of the satellite receiving antenna has no need to be guaranteed to be identical with a longitude and latitude coordinate of the measured point, thereby reducing operation difficulties.
Owner:HERONAV BEIJING TECH DEV

Irregular Venturi flowmeter and method for measuring gas-liquid phase flow in multiphase flow by utilization of irregular Venturi flowmeter

InactiveCN105675070AChange the upstream and downstream symmetrical structure designSimple structureVolume/mass flow by differential pressureIndirect mass flowmetersThroatStraight tube
The invention discloses an irregular Venturi flowmeter, comprising a Venturi tube and at least three pressure probes, wherein the Venturi tube is composed of a front straight tube section, a contraction section, a throat section, an expansion section and a rear straight tube section; all the sections are connected in sequence; the inner diameter of each of the front straight tube section and the rear straight tube section is D; the inner diameter of the throat section is d; each of the contraction section and the expansion section is conical; the structural parameters of the Venturi tube are as follows: beta=d/D=0.45 to 0.75, the length of the throat section is 2d to 8d, the conical degree of the contraction section is 10.5 degrees, and the conical degree of the expansion section is 7.5 degrees. The invention further relates to a method for measuring gas phase flow and liquid phase flow in moisture by utilization of the irregular Venturi flowmeter. The irregular Venturi flowmeter is especially suitable for measuring downhole moisture flow, and is especially used for monitoring the gas phase flow and the liquid phase flow in an underground connected well connecting a main gas reservoir with a related gas reservoir in the process of manual migration and development of related oil-gas reservoirs in real time.
Owner:CHINA NAT OFFSHORE OIL CORP +2
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