106results about How to "Suitable for measurement" patented technology

The invention discloses a method for measuring zero-sequence parameters of double-circuit transmission lines. The method comprises the following steps: measuring the zero-sequence parameters of the double-circuit transmission lines in the manner of live line measurement or power cut measurement; by utilizing the global positioning system technology, simultaneously measuring the zero-sequence voltage and the zero-sequence current at the head ends and the tail ends of the double-circuit transmission lines to realize synchronous sampling on the zero-sequence voltage and the zero-sequence current; and then, working out the respective zero-sequence self impedance and zero-sequence self capacitance, and zero-sequence mutual impedance and zero-sequence mutual capacitance between the double-circuit transmission lines. In the method for measuring the zero-sequence parameters of double-circuit transmission lines, the distributed parameter models of the double-circuit transmission lines are established, and the influences of distributed capacitors on measured results are considered, thereby, the accuracy of the measured results of the zero-sequence parameters of the double-circuit transmission lines is greatly improved.

The invention discloses a single-slit spatial carrier shearing speckle interferometry measuring system and a measuring method. The measuring system and the measuring method are characterized in that laser shot by a laser device passes through a beam expander and then irradiate a measured object in the form of diffusion light, diffuse reflection light on the surface of the measured object sequentially passes through an imaging lens, a slit diaphragm, a 4f system and a Michelson type device to be projected onto a target surface of an CCD camera. The measuring system and the measuring method can carry out nondestructive, full-field, rapid and dynamic measurement for the defects and stress deformation of the surface of the measured object and is convenient for field measurement.

The present invention is a method for extracting electromagnetic parameters of artificial electromagnetic material based on support vector machine (SVM). The invention relates to a new method for researching electromagnetic parameter measurement, capable of testing shield-hand material and artificial electromagnetic material having a periodic structure, and the testing result precision is high andthe production of testing samples is simple. The support vector machine (SVM) method is based on a VC-dimension theory of a statistical learning theory and a structure risk minimum principle, seeks an optimum compromise between the complexity and the learning capacity of a model based on limited sample information so as to obtain best popularization capability, and is widely applied to statistical classification and regression analysis. According to the invention, transmission and reflection coefficients of material to be tested are calculated by numerical computation methods FEM and FDTD ofelectromagnetism, and the corresponding computed result is used as training sequences to train the the support vector machine. When the support vector machine is trained fully, it is capable of calculating equivalent dielectric constant and equivalent magnetic conductance of the material to be tested by inputting testing values of the transmission and reflection coefficients.

The invention relates to a new method for measuring electromagnetic parameters, which is required to measure left-hand materials and artificial electromagnetic materials with periodic structures and have high measurement result precision, and the manufacture of a measurement sample is simple. A neural net arithmetic is a biological computation method which is suitable for a highly nonlinear problem, and is already widely applied to the other field of information processing computation and proved to be a better arithmetic. The method combining the neural net computation with a computing electromagnetics method computes transmission and reflection coefficients of measured materials by number value computation methods FEM and FDTD of computation electromagnetics and training neural nets by taking corresponding computing results as a training sequence. When the neural nets are sufficiently trained, the effective dielectric constant and the effective magnetic conductivity of the measured materials are computed through measurement values of the transmission and reflection coefficients.

The invention discloses a rapid measuring method for the growing height of agricultural crops in mountainous areas based on an unmanned aerial vehicle photographed image. The method comprises the following steps: acquiring the geographical coordinates of all ground control points and the surface elevation value H; acquiring an initial image P1 and a measurement image P2; establishing elevation dense point clouds; generating respectively a ground splicing image and digital surface model data; generating a three-dimensional model for an agricultural crop growing area and extracting from the three-dimensional model the bare soil elevation value and the measurement elevation value; and outputting the growing height of the agricultural crops. According to the invention, through an unmanned aerial vehicle, it is possible to obtain what is influential in the growing process of agricultural crops; and through the cooperation with the ground control points, DSM data are generated and a three-dimensional model is obtained; and from the three-dimensional model, the growing height of the agricultural crops in each period can be further obtained. With a spatial analysis method to extract the growing height of agricultural crops, the method does not require much on the terrains, therefore, making it suitable for the height measurement of different types of agricultural crops in different growing periods. Capable of measuring at a short time, the method also achieves high efficiency and good measurement precision.

This invention relates to an alarm for testing fatigue of drivers composed of a glass with a reflection fiber shift sensor and an intelligent control system, which takes the expression of fatigue of the eye part as the primary standard to set up a math model to monitor the flash frequency of eyelid, the close time, running of eye balls and pupil contraction and expansion so as to emit acousto-optical warning or force it stopping.

The invention discloses an optical method, a device and an application for measuring supersonic wave sound pressure and sound intensity The optical method comprises steps illuminating the supersonic wave by a parallel beam in a direction perpendicular to the propagation of the supersonic wave, obtaining a diffraction frequency spectrum of a raster, receiving zero order spectrum diffracted light, obtaining a corresponding voltage value through a reversing and amplification circuit and a sampling processing circuit, obtaining the amplitude of the sound pressure to be measured by comparing with a calibration value obtained beforehand and calculating the sound intensity. The device provided by the invention comprises a power supply, a signal compensation circuit, a signal collection circuit, the signal reversing circuit, the signal amplification circuit, a computer, a light source, a light outgoing diaphragm, a light outgoing window, a light incident window, a convex lens, a filtering diaphragm and a photoelectric detector, wherein the light source, the light outgoing diaphragm, the light outgoing window, the light incident window, the convex lens, the filtering diaphragm and the photoelectric detector are successively arranged along the heading direction; the light source is connected to the power supply and the signal compensation circuit; the photoelectric detector, the signal reversing and amplification circuit, the signal compensation circuit, the signal collection circuit and the computer are successively connected. The invention has strong measurement directivity and practicability.

This invention is variable density fibre complex conductivity in situ synthesis measuring method and device. Apply force on fibre plug, change the density of the fibre plug, and apply air, voice, electricity, heat, humidity effects. And use force, air, voice, electricity, heat, humidity sensor to measure the change of the physical appearance density and distribution. The device can improve the structure and isolation of the push silo, fiber plug and measure chamber, and add measure units , related drive and control circuit, modular used for data collection and treatment and interface control, in push silo and measure chamber. This device can actualize the conduction, isolation of variable density fibre complex's in situ synthesis measurement. This measurement has high accuracy and little disturbance. It can be widely used in many kinds of measurement.

The invention discloses an experiment device and method for evaluating synthetic jet plate turbulent flow drag reduction. The device comprises a low turbulent flow static wind tunnel, a test platform,a force test balance, a smoke generator an LDV laser velocity measurement device, a synthetic jet plate turbulent flow drag reduction device, wherein the test platform is fixedly arranged in an experiment segment of the low turbulent flow static wind tunnel, and the test platform comprises a fixing support, a zero pressure gradient flat plate and a guide rail. The method is characterized in thatfirstly, the flat plate with zero pressure gradient is established in the wind tunnel, flow field distribution of the flat plate having no excitation device is detected, secondly, the excitation device is added to the flat plate, flow field distribution is detected when the excitation device is in a non-open state, and lastly, the excitation device is opened, flow field distribution is detected when the excitation device is in an open state. Friction resistances under different states are calculated through Spalding formula fitting, and the actual drag reduction effect of the synthetic jet plate turbulent flow drag reduction device is acquired through analysis. The method is simple for operation, and the method is suitable for measuring the drag reduction effect of various types of drag reduction devices.

The invention relates to a fiber Bragg grating vortex shedding flow meter based on a triangular prism-shaped vortex-forming body and a using method thereof, and belongs to the technical field of photoelectronic measurement. The fiber Bragg grating vortex shedding flow meter is characterized in that the triangular prism-shaped vortex-forming body is fixed inside a measuring tube through bases at the two ends, and the two side faces at the middle part of the triangular prism-shaped vortex-forming body are communicated with each other, so as to form a pressure guide cavity; in the pressure guide cavity, a free end of a constant strength cantilever is provided with a mass block, and a fixed end of the constant strength cantilever is connected with an axial conduit inside the triangular prism-shaped vortex-forming body; and the fiber Bragg grating is stuck to the central axis of the surface of the constant strength cantilever, and the fiber Bragg grating is connected with an external fiber through an axial conduit and a fiber out-leading hole. The fiber Bragg grating vortex shedding flow meter based on the triangular prism-shaped vortex-forming body provided by the invention has the beneficial effects that by adopting the triangular prism as the vertex-forming body, very high reliability is provided for flow detection; and by adopting the fiber Bragg grating as a sensing element, the meter can resist electromagnetic disturbance, is suitable for measuring the flow of various fluid, and particularly has a very good prospect for measuring the flow of fluid with chemical corrosion.

A uniform velocity tube of flow rate transducer consists of high pressure sampling hole at flow receiving surface, low pressure sampling hole at side surface between flow receiving surface and flow departing surface which are built on tube wall of the uniform velocity tube . It features that the said tube section is prepared to be a bullet head form so fluid is splited along two side surfaces of said tube section formed as bullet head to make a flow coefficient relatively stable when fluid flows through the tube.

The invention provides a thin film test sample platform of an X-ray diffraction instrument. The thin film test sample platform is formed by a fixing bracket, three springs, a flat plate type sample holder and an adjusting screw, wherein the fixing bracket is in a right-angle Z shape; a screw hole and three spring hook holes are formed in the center of a flat plate below the fixing bracket; three spring pull hook holes are also formed in the flat plate type sample holder; the flat plate type sample holder passes through the three springs to be respectively connected with the fixing bracket through the pull hook holes; the adjusting screw penetrates through the screw hole of the fixing bracket to be contacted with the lower bottom face of the sample holder; the height of the sample holder can be freely adjusted through the adjusting screw; finally, the surface of a sample and the upper surface of the fixing bracket are on the same plane. According to the thin film test sample platform, X-ray diffraction measurement of the samples with the different specifications can be conveniently carried out, and particularly, the X-ray diffraction measurement of thin film samples with different substrate thicknesses can be realized.

A nuclear density gauge and test method is provided for measuring density material in a relatively thin zone beneath a surface of the material. The gauge comprises a gauge housing and a substantially planar base on said gauge housing adapted to be positioned on a surface of the material sample. A gamma radiation source having a characteristic primary energy and an activity of no more than 100 microcurie is mounted within the housing and cooperates with the base for emitting gamma radiation through the base and into an underlying material sample. An energy selective gamma radiation detector is mounted within the gauge housing and in laterally spaced apart relation from the gamma radiation source. The gamma radiation detector is operable for quantifying the energy level of the detected gamma radiation. Shielding is provided within the gauge housing between the source and the detector for preventing gamma radiation from passing directly from said source to the detector. An analyzer is connected to the detector for detecting gamma radiation counts in a predetermined energy spectrum having a lower limit of 0.1 MeV or greater and an upper limit which is less than the characteristic primary energy of said source. The density of the sample is calculated based upon the gamma radiation counts obtainedby the analyzer within the predetermined energy spectrum.

The present invention provides a spectral imaging device based on adaptive optics. The device comprises a collimator (1), a tilting mirror (2), a wavefront corrector DM (3), a dichroic spectroscope (4), a wavefront detector (5), a wavefront controller (6), an imaging system (7), a telescope instant image surface (8), a relay optical system (9), a telescope secondary image surface (10), an image splitter (11), a slit (12), a collimating lens (13), a grating (14), an imaging lens (15), a detector (16) and a data processing and control computer (17). The spectral imaging device based on the adaptive optics employs the dispersion light splitting mode after the image surface cutting conversion so as to obtain the object spectrum and image information while the single exposure; and moreover, through combination of the adaptive optics technology, the wavefront detector is introduced to detect the aberration in real time, and the tilting mirror and the wavefront corrector are configured to perform real-time correction so as to solve the problems of the atmospheric disturbance and the non-scanning rapid obtaining of the three-dimensional information and especially fit for the measurement of a rapidly changing target.

The invention belongs to the technical field of manufacture and measurement of measuring devices, more particularly relates to a high-precision automatic measurement method of axial size of abrupt-change cross section of a revolving body. The measurement method is based on the principles of adopting a high-precision linear array CCD optical imaging technology and a high-precision motion control technology, performing rapid measurement on a contour line at longitudinal section of the revolving body to obtain contour data of the revolving body, calculating curvature change of the contour line of the revolving body, and seeking local extremum points of the curvature change on the contour line to obtain the axial position of the abrupt-change cross section, thus calculating the axial size of the abrupt-change cross section. The measurement method is suitable for rapid measurement of the axial size of grooves, benches, frustums and the like of various complex revolving body parts, and the method is especially suitable for revolving body parts which are provided with small-space grooves and can not be easily measured by a contact method.

The sensor includes following parts and structures: insulative inertial mass block in cube; four pieces of XO0 cutting type quartz wafer with electrode are jointed four walls of the inertial mass block; the inertial mass block and quartz wafers are instilled inside base frame composed of case body and case cover. Each insulative force transmission block is pasted on outside each quartz wafer. Pretension screw of withstanding each piece of force transmission block is arranged on four walls of the base frame. Through signal lead wire, one end of the case cover is connected to electrode, and the other end is connected to connector plug, which is connected to differential type charge amplifier. The sensor possesses high sensitivity, or, when outside force is smaller, output signal is still strong so as to reduce measuring error brought from environmental change. Features of the sensor are: light weight, simple structure, easy of manufacture.

The invention discloses a mixed-pressure bipolar direct-current power transmission line zero-sequence parameter precisely measuring method. Bipolar head ends and tail ends of direct power transmission lines different in voltage level are respectively connected, zero-sequence voltages and zero-sequence currents on head and tail ends of the mixed-pressure bipolar direct-current power transmission lines are simultaneously measured, and a global satellite positioning system is utilized to realize synchronous sampling of voltages and currents on double ends of the mixed-pressure bipolar direct-current power transmission lines; and then zero-sequence self-impedance, zero-sequence mutual-impedance, zero-sequence self-capacitive-reactance and zero sequence mutual-capacitive-reactance of the mixed-pressure bipolar direct-current power transmission lines are obtained by means of calculation. According to the invention, a distributed constant model of the mixed-pressure bipolar direct-current power transmission lines is established, and the influences of distributed capacitance on the measuring result are considered, so that the precision of mixed-pressure bipolar direct-current power transmission line zero-sequence parameter measurement is substantially improved.

The invention discloses a measure method applied to a circuit of a resistor-type moisture measure sensor, and relates to the field of measuring of grain moisture. The circuit comprises a power supply unit connected with a CPU acquisition processing unit and a voltage-raising voltage-stabilizing unit; the voltage-raising voltage-stabilizing unit is connected with an electron change-over switch respectively via a first standard resistor, a second standard resistor and a third current-limiting resistor; the electron change-over switch is connected with the CPU acquisition processing unit, an operational amplifier and a second triode; the operational amplifier is connected with a first triode and the second triode, and also the output terminal of the operational amplifier is connected with a reverse-direction input terminal via a capacitor; the voltage-raising voltage-stabilizing unit is connected with the second triode via the first triode; and the voltage-raising voltage-stabilizing unit is connected with an A / D acquisition module via a transition linearity correction amplification processing unit. When moisture in grains is measured, the measuring speed is fast, the measuring scope is relatively wide, and also the measuring stability is relatively high. The measure method is relatively wide in application scope.

The invention provides a solar battery IPCE curve measuring device. The device comprises a light source device, a short circuit current measuring device and a calculation device, wherein the light source device is used to provide two beams of identical monochromatic light at the same time; the short circuit current measuring device is used to measure the short circuit photocurrent of a reference cell with a known response coefficient and a to-be-measured cell, and both cells are synchronously irradiated by the two beams of identical monochromatic light respectively and have identical illuminated areas; and the calculation device is used to calculate the IPCE values of the to-be-measured cells corresponding to monochromatic light of different wavelengths. The invention also provides a corresponding IPCE curve measuring method. The device and the method are capable of effectively inhibiting errors caused by output light intensity drift of a light source and accurate and intuitionistic and not influenced by battery capacitor characteristics and response speed and therefore are particularly suitable to measure the IPCE curve of a DSC battery. The embodiments of the invention can also increase the signal noise ratio of to-be-measured short circuit photocurrent signals.

The invention discloses a T-type electric transmission line positive sequence capacitance measuring method. The method specifically comprises the steps: a T-type electric transmission line to be measured is disconnected with electricity, positive sequence voltage is sequentially exerted on the head ends of three branch lines of the T-type electric transmission line, the rest tail ends of the branch lines without the voltage are opened in a three-phase mode, a positive sequence fundamental wave voltage phasor and a positive sequence fundamental wave current phasor are obtained through a Fourier algorithm by positive sequence voltage data and positive sequence current data obtained at the voltage exerting ends, and a positive sequence capacitance parameter of each branch line of the T-type electric transmission line is calculated through a relational expression of the positive sequence fundamental wave voltage phasor and the positive sequence fundamental wave current phasor. The T-type electric transmission line positive sequence capacitance measuring method overcomes shortages of an existing measuring method and improves accuracy of a measuring result of the T-type electric transmission line positive sequence capacitance parameters.

The present invention relates to a differential piezoelectric acceleration transducer. It includes an isolated base seat which uses vertically-drawn central line of H-type section as axis and can be rotated at 180 deg. to form rotator and a shell body which is cover-mounted on said base seat and is equipped with a plug socket. On the upper disk surface of said base seat from bottom to top are successively fixed Teflon washer, electrode, lower piezoelectric element, electrode, Teflon washer, inertial mass block, Teflon washer, electrode, upper piezoelectric element, electrode and Teflon washer. The signal lead wires connected with piezoelectric elements are directly connected on the all electrodes respectively, and said shell body is fixedly coupled with lower disk of said isolated base seat.

The invention relates to a measuring device (1) for measuring an electrical current, comprising a light source (5) for generating a polarised primary light signal for feeding into a Faraday sensor unit (2), and comprising a detector (6) for detecting a secondary light signal provided by the Faraday sensor unit (2) and polarisation-altered in relation to the primary light signal. The invention is characterised by an optical-electrical compensation element (8, 9, 10), by means of which the polarisation alteration of the secondary light signal can be compensated via an opposite polarisation alteration, and a measurement signal, according to the opposite polarisation alteration, for the electrical current can be deduced. The invention also relates to a method for measuring an electrical current by means of the measuring device (1).

The invention belongs to the technical field of micro inertial navigation, and particularly relates to a triaxial accelerometer device for tunnel magnetoresistance detection. The triaxial accelerometer device for tunnel magnetic resistance detection is composed of a bonding substrate, a support frame, a sensitive mass block, a detection beam, a connecting block, a cantilever beam, a detection magnet, a tunnel magnetoresistive element and a signal line. The sensitive mass block, the detection composite beam and the cantilever beam are arranged on the support frame; a detection magnet is arranged on a sensitive mass block, the sensitive mass block and detection combination beams located on the two sides of the sensitive mass block jointly form a rectangular detection structure, the rectangular detection structure is located in the axis direction of the detection direction of the overall structure of the triaxial accelerometer device, and high-precision acceleration detection is achieved.The structure of the device has high sensitivity to weak magnetic field change, and the device is reasonable and simple in design, easy in monolithic integration and suitable for microminiaturization.

The invention relates to the measuring technique for dielectric medium dielectric coefficients under microwave frequency, and discloses a medium dielectric coefficient measuring probe with a coaxial line structure under the high-temperature condition, wherein the measuring probe is used for measuring medium dielectric coefficients under the high-temperature condition. According to the technical scheme, the medium dielectric coefficient measuring probe with the coaxial line structure under the high-temperature condition comprises a measuring section and an interface section, wherein one end of the interface section is connected with the measuring section, the other end of the interface section is of a coaxial joint structure, media between an inner conductor and an outer conductor of the interface section are high-temperature resistant heat insulation solid media, the inside diameter of an outer conductor of the measuring section is slightly smaller than that of the outer conductor of the interface section so that the high-temperature resistant heat insulation solid media can be prevented from falling off and microwave reflection can also be reduced, the space between an inner conductor and the outer conductor of the measuring section is of a hollow structure, and the inner conductor and the outer conductor of the measuring section and the inner conductor and the outer conductor of the interface section are coaxial. The measuring probe is suitable for measurement of dielectric coefficients of matter under the high-temperature condition, and is high in measurement accuracy within a wide frequency band range.

The invention relates to a physiological parameter detection system and a detection method based on an optical fiber pad. The detection system comprises an optical fiber pad, an analysis device, a communication module, a mobile client and a data analysis module. The optical fiber pad feels tiny pressure of a vibration signal of a human body. The pressure exerted on the optical fiber and changes the transmission of light. The analysis device converts the optical signal obtained from the human body pressure on the optical fiber into a voltage signal. The waveform parameters and physiological parameters are transmitted to the mobile client through the communication module. The measured data are stored and displayed. The data analysis module analyzes the measured data, tracks the physiologicalparameter information of the user, judges the physiological status of the user and provides guidance and suggestions. The physiological parameter detection system and method are non-inductive measurement, and stable measurement of respiration and heart rate is realized on the signal processing method, and have good application prospect in the field of health monitoring and chronic disease management.

One kind used for then the hold type nuclear magnetic resonance instrument quiet the magnetic field take place equip of always body, from a hollow cylinder form always body and a hollow hemisphere form always body constitute, hemisphere form the stalk of body always cuts one that the noodles folds to impose a cylinder form always a body to carry noodles up. Hollow cylinder form always body from shape homology, the magnetic field strength is equal, magnetizing a direction to revolve a direction for the body double and fan-shaped the body always constitutes. Hemisphere form always body is with the outside path be equal to a cylinder form a body always of outside path, inside path small in cylinder form always body of inside path, the stalk runs parallel with the semicircle wreath of magnetic field direction, the stalk which rounds to run parallel with a magnetic field direction revolves to get of, the hemisphere's form the body always closes the cylinder form body to carry a department at hollow type cylinder form the outside side of the body at the right moment. Hemisphere form always body and cylinder form the body always compensates a cylinder form consistently and in order to a body to always carry the horizontal magnetic field of department in the on-line magnetic field direction of the cylinder stalk inside the chamber.

The invention discloses a novel capacitive liquid level sensor based on the capacitance calculation principle and the application thereof. The novel capacitive liquid level sensor comprises a shielding cover, an insulator, a metal layer, an upper packaging piece, a circuit board, a special metal pin and a lower packaging piece. The insulator is shaped like a barrel, and the outer surface of the insulator is plated with the metal layer. The shielding cover is coaxial with the insulator and located on the periphery of the insulator, and the insulator and the shielding cover are assembled together through the upper packaging piece and the lower packaging piece. A positioning and clamping surface is arranged outside the upper packaging piece, and the signal processing circuit board is arranged inside the positioning and clamping surface. Small holes through which liquid can flow are evenly distributed in the shielding cover. Based on the capacitance calculation principle, the precision of the capacitive liquid level sensor is only influenced by the relative dielectric constant of the liquid to be measured and the relative dielectric constant of air and is expected to be improved than that of a traditional capacitive liquid level sensor, and the novel capacitive liquid level sensor is also suitable for measurement of the level of ultralow-temperature liquid.

The invention discloses a satellite radar altimeter tracker compatible of sea and land, which comprises a first FFT power analyzer, an MLE error discriminator, a first Alpha-Beta filter, a second FFT power analyzer, an OCOG error discriminator, a second Alpha-Beta filter and a data composing treatment unit; wherein, the first FFT power analyzer is electrically connected to the MLE error discriminator, the first Alpha-Beta filter and the data composing treatment unit. The MLE error discriminator is respectively connected with the first Alpha-Beta filter and the data composing treatment unit electrically. The first Alpha-Beta filter is electrically connected with the data composing treatment unit. The second FFT power analyzer is electrically connected with the OCOG error discriminator, and the second Alpha-Beta filter and the data composing treatment unit. The OCOG error discriminator is respectively connected with the second Alpha-Beta filter and the data composing treatment unit electrically. The second Alpha-Beta filter is electrically connected with the data composing treatment unit. The first Alpha-Beta filter is also electrically connected with the second Alpha-Beta filter.

The present invention discloses an experimental device and method of assessing dielectric barrier discharge plasma flat plate turbulent drag reduction. The device comprises a low turbulence silent wind tunnel, a test platform, a force measurement balance, a smoke generator, an LDV laser velocity measurement device, a dielectric barrier discharge plasma flat plate turbulence drag reduction device,and the test platform is fixedly arranged in an experimental segment of the low turbulence silent wind tunnel and comprises a fixing support, a zero-pressure gradient flat plate and a guide rail. Theprinciple of the method is that firstly the zero-pressure gradient flat plate is built in the wind tunnel to measure the flow field distribution when an excitation device is not arranged on the flat plate, and then the excitation device is added in the middle of the flat plate to measure the flow field distribution when the excitation device exists but is not turned on, and finally, the excitationdevice is turned on to measure the flow field distribution when the excitation device is added and is turned on. A Spalding formula is used to fit and calculate the friction resistance under different states, and the actual drag reduction effect of the dielectric barrier discharge plasma flat plate turbulence drag reduction device is analyzed. The method is simple to operate, and is suitable formeasuring the drag reduction effects of various drag reduction devices.

The invention discloses a quantitative measurement method of ultrasonic grating phase amplitude. The quantitative measurement method specifically comprises the following steps: expanding and collimating monochromatic light emitted by a light source, then irradiating the ultrasonic grating in a direction perpendicular to an ultrasonic wave propagation direction and transforming through a lens to obtain a diffraction frequency spectrum of the ultrasonic grating; recording the diffraction frequency spectrum of the ultrasonic grating, calculating to obtain diffraction light intensity ratio of the diffraction frequency spectrum, substituting the diffraction light intensity ratio into a quantitative relation expression between the diffraction light intensity ratio and the ultrasonic grating phase amplitude to solve the phase amplitude of the ultrasonic grating. The quantitative measurement method of ultrasonic grating phase amplitude has the advantages that the quantitative measurement method is capable of obtaining average phase amplitude of a phase grating, quick in measurement speed, easily realizing automatic measurement, applicable to phase amplitude measurement of sine or cosine phase grating, especially applicable to measurement of dynamic periodic phase objects and simple to operate.