41 results about "Brownian motion" patented technology

The invention relates to the field of thermal fault early warning of machine room inspection robots, in particular to a multi-modal sensing thermal fault early warning method of a machine room inspection robot, which comprises the following steps: acquiring infrared thermal image, acoustics, vibration and gas concentration data through a multi-modal sensor array, and generating voxelization temperature distribution; according to the method, temperature features are extracted through wavelet transform and a fractional Brownian motion algorithm and are fused into an equipment global temperature feature set; constructing noise, vibration and gas concentration tower extraction auxiliary features, and combining non-extensive entropy and a graph attention model to be fused into a high-dimensional fault feature pool; building a fiber bundle model by taking the machine room topology as a base space, and locating a thermal fault after optimizing parameters by a simulated annealing algorithm; and finally, a dynamic thermodynamic diagram and the like are generated through digital twinning, so that accurate early warning is realized.

The invention relates to a multi-dimensional degradation control method and system based on self-encoding and fuzzy modeling, and is suitable for health management and life prediction of industrial equipment. The system collects equipment degradation data through multiple sensors, constructs a three-dimensional tensor and performs data fusion and weight optimization by using CP decomposition and an entropy weight method; detecting a multi-dimensional collaborative change point by adopting a mahalanobis distance and a combined likelihood ratio; low-dimensional features are extracted through an auto-encoder, and degradation modes are divided in combination with a clustering algorithm; establishing a joint degradation equation fusing a drift term matrix, diffusion covariance and fractal Brownian motion, and depicting long-range dependence; on the basis of fuzzy Markov chain modeling state transition fuzziness, a multi-dimensional degradation path is generated in combination with a Copula-Monte Carlo algorithm, the sample weight is dynamically adjusted, and the residual life distribution is estimated and predicted by using kernel density. According to the method, the degradation modeling precision and working condition adaptability of the complex industrial equipment are improved, and technical support is provided for precise life prediction and health management.

The invention provides a hybrid MPPT (Maximum Power Point Tracking) control method based on a chaos initialization Levy flight Swane algorithm and an improved conductance increment method, belongs to the field of photovoltaic power generation systems, and aims at enhancing population diversity through chaos initialization, improving global search capability in combination with a Levy flight strategy and switching to the improved conductance increment method in an optimal solution neighborhood to realize high-precision tracking. The Logistic chaotic mapping initialization is combined to solve the problem that local optimum is caused by periodic values or uneven distribution easily occurring in the random initialization of the traditional South goose algorithm, the Brownian motion of the original South goose algorithm is changed into the Levy flight, the dynamic beta is increased, the global exploration and local exploration capabilities are balanced, local optimum is avoided, the improved conductance increment method is combined, and the local optimization is improved. And finally, the optimal duty ratio is screened by using a sliding window to lock the output, so that the problem of insufficient MPPT precision of a traditional optimization algorithm is solved, and the problem of power jitter near the maximum power point of a traditional conductance increment method is solved.

The present invention belongs to the field of particle motion trajectory identification technology, and in particular, is a method for tracking a large number of moving particles based on image recognition. The moving particles applicable to this method are particles undergoing active Brownian motion. The same color mark is made on each moving particle, and images are collected using a microscope or video recorder. Then, by setting RGB values, the pixel cluster corresponding to the color mark on each moving particle is identified. By setting thresholds in the pixel clusters, the moving particles corresponding to the color mark are determined. The pixel corresponding to the average position of all position data is taken as the position of the moving particle. The movement trajectory of the moving particles over a period of time is recorded. In the present invention, by introducing marks on the particles, an algorithm is developed to realize the recognition of the marks, calculate and record the average position of the pixels corresponding to the marks, and realize the tracking of the particles. The color marks can be stable and do not interfere with each other, which can ensure that a large number of particles can be tracked for a long time.

The invention discloses an intelligent optimization regulation and control system and method for coal mine gas extraction, and relates to the field of intelligent optimization regulation and control for gas extraction, and the system comprises a geological module, an equipment module, a calculation module, a control module and an environment module. Calculating a control parameter combination of the coal-mine gas extraction equipment, creating a Brownian motion control model of the coal-mine gas extraction equipment, generating corresponding state change data of the coal-mine gas extraction equipment through the Brownian motion control model, analyzing to obtain an interval comprehensive change value of the gas extraction equipment, and establishing a neural network model; according to the method, the opening degree instruction of the electric air supplement valve is analyzed, the electric air supplement valve is driven to adjust, the air supplement amount is adjusted, multi-dimensional parameter PID control can be adopted, the adaptability is high under the complex geological condition, the equipment state response is timely, and the control strategy optimization meets the requirement.

The invention relates to an aerogel microstructure reconstruction method and system based on potential energy driving, belongs to the technical field of aerogel materials, and solves the problems of low aerogel microstructure reconstruction precision and difficult porosity control in the prior art. The method comprises the steps of generating target particles based on aerogel particle characteristics, generating a current Brownian motion parameter based on a random diffusion model, calculating aggregation potential energy when the target particles displaced based on the current Brownian motion parameter are in contact with an existing aggregation particle cluster, and when a potential energy threshold value is reached, calculating the current Brownian motion parameter. Determining the target particles and the existing aggregated particle cluster as a current aggregated particle cluster; and calculating the particle number of the current aggregated particle cluster, calculating the current porosity of the current aggregated particle cluster when the contact particle number requirement is met, and outputting the microstructure of the current aggregated particle cluster as the microstructure of the reconstructed target aerogel if the target porosity is reached. And effective control and accurate reconstruction of the porosity of the aerogel microstructure are realized.

A method, comprising: determining electrophoretic mobility associated with a particle in a transverse alternating force microfluidic channel; determining a size of the particle based at least in part on one of Brownian motion of a particle or one or more images of the particle. A system comprising: a microfluidic channel; a plurality of electrodes oriented transverse to the microfluidic channel, the plurality of electrodes comprising an alternating electric field; and a classification system configured to: determine one or more of the following: an electrophoretic mobility associated with a particle in the transverse AC microfluidic channel and / or determine, based at least in part on the electrophoretic motion, and size from image analysis or Brownian motion of a particle or one or more images of the particle, particle shape, particle deformability, for recognition of surface characteristics, such as assaying for receptors and ligands, and to perform electroporation.

Illumination light is irradiated to a flow path, and scattered light emitted from particles contained in a sample passing through a detection region formed in a prescribed section is condensed and captured at a prescribed frame rate at a position virtually extended in a flow direction of the sample. On this basis, an amount of movement of the particles in a direction perpendicular to the flow direction due to Brownian motion is calculated based on a plurality of frame images. Furthermore, in order to correct an error in the amount of movement on the image due to the magnification at the defocus position, the amount of movement is corrected using a correction value calculated in advance, and the particle diameter is determined.

The invention relates to the technical field of fluid separation, in particular to cascade separation equipment for mixed gas, which comprises a first separation cavity, a second separation cavity and a rotary drum, the first separation cavity rotates coaxially, the second separation cavity is arranged at the radial far end of the first separation cavity, and the rotary drum penetrates through the interior of the first separation cavity. The included angle between the tangent line of any point of the inner wall of the first separation cavity and the axis of the rotating shaft in the same plane is smaller than 90 degrees, and a drainage piece for guiding mixed gas to flow to the second separation cavity and a plurality of blades for enabling the mixed gas to be in a laminar flow state are arranged in the first separation cavity. And the use requirements in multiple fields can be met. Meanwhile, the invention also relates to a separation method, the separation of the mixed gas is realized by using the separation equipment and based on four physical mechanisms, namely the action of strong centrifugal force, layered flow and an environment in which the mixed gas is in a laminar flow state and the Brownian motion is inhibited, and the separation efficiency and the separation effect are greatly improved.

The Magnus roller of known type - when used alone - is altered in its reactive resultant by redirecting a wind coming from the front, a wind current or a driving wind (when mounted on a vehicle) or the wind currents composed of both, so that a sideways shearing movement does not result as before, but a movement exactly opposite to the wind coming from the front, whereby, however, due to partial covering at the front, the yield is initially less than the force of the sideways shearing before. When mounting multiple Magnus rollers on a single drum, we must consider the additional wind generated by the rotation of the rotating drum (which is cranked by the rollers) in the half facing the oncoming wind. This results in a combined effect of both winds, which must be addressed by adjusting the covers and deflecting guide plates or by further rotating the drum. This is achieved through automatic control depending on the roller position. Since the rollers on the rear side of the rotating drum move in the opposite direction, the (rotational) wind there comes from, for example, an oblique angle above, while on the front half of the drum, with the same oncoming wind, the (rotational) wind comes from an oblique angle below. Accordingly, the feeds / deflections and opening points must be adjusted, or the rear section, in the second...Half of the roller should be adjusted to face only the oncoming wind. The onshore wind must be blocked on the rear half of the roller by a side shield on each roller. Alternatively, by opening an upper guide plate (if applicable), only a portion of the downward-approaching wind (resulting from the roller's rotation) can be utilized. By utilizing the absorption of solar heat stored in the Brownian motion of molecules, which occurs during flows on the laminar half, by means of flow-induced alignment of these molecules not irregularly in all directions, but rising in the direction of flow, a good additional suction is added, which strengthens the resultants of the rolls and thus also accelerates the rotation of the roll.

A method of pretreating a pipeline or apparatus is carried out by selecting a colloidal particle dispersion having inorganic nanoparticles with an average particle size from 500 nm or less that exhibit properties of Brownian motion. Surfaces of a pipeline or apparatus are contacted with a treatment composition comprising the colloidal particle dispersion. The colloidal particles of the treatment composition are allowed to adhere the surfaces of the pipeline or apparatus to facilitate a reduction in friction of the surfaces of the pipeline or apparatus and / or lower the pressure drop of fluid flowing over the surfaces of the pipeline or apparatus and / or to reduce the formation of surface deposits on the surfaces of the pipeline or apparatus.

The application discloses an aerodynamic lens sample injection device for single-particle imaging and belongs to the technical field of particle sample injection. The aerodynamic lens sample injection device comprises a gas removal device, a vacuum connection device and an aerodynamic lens. The gas removal device, the vacuum connection device and the aerodynamic lens are sequentially connected and communicated. The input end of the aerodynamic lens is used for receiving particles transmitted by the vacuum connection device, and the output end of the aerodynamic lens is used for conveying the focused particles to an experimental area. The output end of the aerodynamic lens is provided with an acceleration nozzle. The acceleration nozzle comprises a stepped nozzle and a converging capillary tube. The inner diameter of the stepped nozzle decreases in sequence along the particle conveying direction. One end of the converging capillary tube is a tapered port, and the other end is communicated with the inner cavity of the aerodynamic lens after penetrating through the stepped nozzle. Through cooperation between the above structures, the Brown motion of small particles is inhibited, the particle beam width is smaller, the gas flow is reduced, and the scattering of the gas background is reduced.

To provide a spray device that can enhance performance in separating particles in an atomizing unit and spray a large number of fine particles having a minute particle size that is wide enough to cause Brownian motion.SOLUTION: A spray device is provided with: an atomization tank which can store liquid and whose circumference is covered with wall surfaces; an ultrasonic vibrator that atomizes liquid to generate fine particles; an air blower that discharges conveying air for conveying fine particles into the atomization tank; a feed-out port which feeds out the fine particles together with the conveying air; a first separator having a first inclining surface inclining downward; and a second separator having a second inclining surface inclining downward. The first separator comprises a first edge part and a first connection part. A blowing port is arranged closer to one end in a width direction of the atomization tank than the first connection part. The second separator comprises a second edge part forming a second gap part and a second connection part. The feed-out port is arranged closer to the other end in the width direction of the atomization tank, and a meandering path is formed between the second gap part and the feed-out port.SELECTED DRAWING: Figure 2

The application discloses a true random number generator, which comprises a random number collecting unit and a random number generating unit. The random number collecting unit comprises a high-pressure-resistant closed transparent liquid pool, which contains a mixture of particles in Brownian motion; and a high-speed microscopic imaging device, which periodically takes pictures of a section inside the mixture to obtain multiple frames of pictures. The random number generating unit comprises a digital processor, which processes the multiple frames of pictures to obtain a preliminary random number string A0; and a postprocessor, which processes A0 to obtain a random number sequence.

A method of operating a pipeline or apparatus is carried out by subjecting a pretreated component of a pipeline or apparatus to electrochemical corrosion protection. The pretreated component has surfaces previously treated with a coating of a treatment composition of a colloidal particle dispersion having inorganic nanoparticles with an average particle size from 500 nm or less that exhibit properties of Brownian motion. At least some of the inorganic nanoparticles of the treatment composition are ionically charged nanoparticles. The surfaces of the pretreated component are fresh surfaces or surfaces where any residues or deposits that have been previously formed on the surfaces from prior material contact have been removed prior to being treated.

The invention belongs to the technical field of sensor software calibration, and particularly relates to a weighing sensor calibration method based on an ELM neural network. The method comprises the following steps: firstly, carrying out data acquisition, dividing the data into a training set and a test set according to a proportion, and carrying out normalization processing on the data to obtain experimental data for an ELM (Extreme Learning Model); secondly, relevant parameters of an ELM model are initialized, and sparse regularization is introduced to improve an ELM neural network; then, relevant parameters of the GWO algorithm are initialized, and fractal Brownian motion is introduced to improve the GWO algorithm; and then, optimizing the improved ELM neural network through an improved GWO algorithm by using experimental data to obtain an ELM model optimal parameter for weighing sensor calibration. And finally, calibrating the output of the weighing sensor by using the obtained optimal parameter. Experiments prove that the method can effectively solve the problem that the precision of the weighing sensor is reduced or even fails due to the temperature influence. Experiments prove that the method is simple and effective, and the average RMSE value of the calibrated weighing sensor can be reduced to 0.1298.

Spraying apparatus enabling large-volume generation of particles minute to a Brownian-motion engendering level. An atomization tank stores liquid formulation; an in-tank arrangement of ultrasonic vibration elements atomizes the liquid formulation to generate fine particles; a blower having a blower element for maintaining predetermined rpm blasts into the atomization tank interior through a top-panel blow port conveyance air conveying the fine particles; and a send-out port on the tank releases the fine particles together with the conveyance air. An in-tank baffle plate, situated above the ultrasonic vibration elements and underneath the blow port, is oriented to block liquid columns produced by the ultrasonic vibration elements, and conveyance air supplied through the blow port.

The present application relates to the technical field of fluid separation, and in particular to a cascade separation device for mixed gas, comprising a coaxial rotating first separation cavity, a second separation cavity arranged at the radial far end of the first separation cavity, and a rotating drum penetrating in the first separation cavity, wherein the first separation cavity is in the shape of a rotary body, the tangent line of any point on the inner wall of the first separation cavity and the axis of the rotating shaft in the same plane is less than 90 degrees, the first separation cavity is internally provided with a flow guide for guiding the mixed gas to the second separation cavity and a plurality of blades for making the mixed gas in a laminar flow state, the separation device is simple in structure, small in size, and low in energy consumption, and can meet the use requirements in multiple fields. Meanwhile, the present application also relates to a separation method, which uses the above separation device and is based on four physical mechanisms, i.e. the action of strong centrifugal force, stratified flow, making the mixed gas in a laminar flow state, and inhibiting the Brownian motion, to realize the separation of the mixed gas, and greatly improve the separation efficiency and separation effect.

The present disclosure provides a nano-scale electromagnetic inductance cell comprising at least one permanent magnet and at least one solenoid held within a container filled with a liquid medium with one of the two being suspended in the medium and free to move, generating energy by Brownian motion within suitable ambient temperature ranges. The disclosure further provides an array of such cells for generating electricity on larger scales and use of the disclosed cells and arrays for generating electricity.

The present invention discloses a water treatment dosing method and dosing system based on alum flower detection, which relates to the technical field of water treatment. The method monitors the equivalent parameters of the alum flower morphology in real time, equates the alum flower morphology to spherical particles, and ignores the influence of Brownian motion and fluid shear on the alum flower mechanics. The van der Waals force between the alum flower particles is derived based on the equivalent parameters of the alum flower morphology, and then the Zeta potential is derived. The current metal particle concentration is determined based on the Zeta potential, and the steady-state dosing amount is adjusted based on the current metal particle concentration. The present invention integrates the DLVO mechanical field, electrochemical potential distribution and control theory, constructs a multi-physical field coupling model, realizes real-time updating of force field parameters driven by spatiotemporal data, forms a closed-loop control chain of perception-decision-execution, and significantly improves the system response speed.

The invention belongs to a part surface treatment technology, and relates to a projectile type ultrasonic impact strengthening device for a turbine disc mortise and a use method of the projectile type ultrasonic impact strengthening device. Comprising a turbine disc, a turbine disc tongue-and-groove upper sealing plate, a turbine disc tongue-and-groove outer sealing ring, an ultrasonic tool head amplitude detector, an ultrasonic impact profiling impact head, a turbine disc transverse displacement crawler belt, a turbine disc rotary table, a turbine disc ultrasonic workbench sliding rail, a turbine disc ultrasonic workbench and a turbine disc ultrasonic strengthening workbench. The bullets do Brownian motion in the cavity at a high speed, the surface of the inner wall of the mortise is impacted by the bullets without difference, and therefore the uniform strengthening effect is achieved at all positions of the mortise. According to the method, only a small number of shots are consumed, a positioning tool does not need to be moved, all mortises can be completely strengthened only by rotating the turbine disc along the axis in sequence, the high positioning precision is achieved, and the machining efficiency is remarkably improved.

The invention provides a controllable random porous structure modeling method based on fractal Brownian motion, and the method comprises the steps: carrying out the grid division of a three-dimensional space, and obtaining a regular grid; based on the regular grid, low-frequency noise is generated through the Berlin noise; limiting the structural range of the regular grid through Simplex noise, and generating high-frequency noise; performing noise superposition on the low-frequency noise and the high-frequency noise to obtain fractal Brownian motion; determining a value of an implicit field through fractal Brownian motion; the contour surface of the implicit field is extracted through a Marking Cubes algorithm, and a complete grid is obtained; and carrying out visual display on the complete grid to obtain a modeling model. According to the method, an implicit field with statistical self-similarity and multi-scale characteristics is generated through multi-layer noise superposition, and the complexity of a natural porous structure is perfectly met. And high-flexibility pore control is realized through parameters such as frequency gain, amplitude attenuation and a threshold value, and the calculation efficiency is remarkably improved.

This utility model relates to the field of fluid separation technology, and more particularly to a retention chamber for separating mixed gases. The retention chamber has a hollow structure and can be positioned radially distal to the center of rotation of a primary separation device, rotating coaxially and synchronously with the primary separation device, and the two are connected. A Brownian motion suppressor is provided circumferentially inside the retention chamber, which effectively prevents the remixing of different gas components after separation, improving separation efficiency. Simultaneously, the retention chamber has a first end and a second end arranged axially inclined, with the internal space gradually increasing from the first end to the second end. A first exhaust port is located radially proximal to the first end, and a second exhaust port is located radially distal to the second end. This inclined shape allows different gas components to accumulate in different areas, which is beneficial for improving the purity of the separated gas and facilitates disassembly. This retention chamber has a simple overall structure and small size, and can be used to improve various traditional centrifuge devices on the market.

The invention discloses a preset control method of a turbojet engine based on random output regulation, which comprises the following steps: constructing a random output regulation equation, then solving the random output regulation equation to obtain a solution of the random output regulation equation, and obtaining a state feedback controller according to the solution of the random output regulation equation; and finally, the turbojet engine measures the blade rotating speed and an external signal, after the fuel flow speed is calculated based on the state feedback controller, the turbojet engine is controlled according to the fuel flow speed obtained through calculation, the blade rotating speed tracks the external signal and reaches a stable state, and therefore output adjustment of the turbojet engine is achieved. The bounded solution of the random output adjustment equation does not depend on Brownian motion, and the output adjustment problem of the turbojet engine can be solved without estimating the Brownian motion. When Brownian motion is measurable, an external signal is allowed to be a bounded signal compared with the prior art.

The utility model discloses a mixed cyclone which comprises a main pipeline, a branch pipeline is fixedly communicated with the middle of the main pipeline, a plurality of groups of third cyclones and a plurality of groups of second cyclones which are positioned on two sides of the branch pipeline are fixedly mounted in the main pipeline, and the third cyclones and the second cyclones are axially arranged towards two sides at intervals. A plurality of groups of first cyclones which are arranged along the axial direction are fixedly mounted on the branch pipeline, and a first flow guide plate and a second flow guide plate which are positioned on two sides of the branch pipeline are fixedly connected in the main pipeline. According to the utility model, when gas passes through the first cyclone and the second cyclone, the gas flow direction is deflected and rotated along the axial direction, a flow field is changed, irregular Brownian motion is strengthened, collision and fusion between two types of gas molecules are strengthened, and then, after the gas subjected to primary mixing passes through the third cyclone, the gas flow direction is changed, and the gas flow direction is changed. The flow field is changed again, so that the mixing time is greatly shortened, and the length of the mixing section is reduced.

The present application belongs to the technical field of quality measurement, and particularly relates to a method for synchronously measuring water content quality and dry quality of living cells. The method comprises the following steps: capturing a cell to be measured by an optical tweezer; illuminating the cell to be measured based on a probe light source, so that the probe light is divided into backscattered light and forward scattered light; measuring a motion trajectory of the cell to be measured by using the backscattered light, and processing the motion trajectory into an instantaneous velocity power spectral density; generating a spatial distribution of phase delay of cell contents to the probe light by using the forward scattered light, and processing the spatial distribution into a phase shift distribution of the probe light after penetrating through the cell; fitting the instantaneous velocity power spectral density by using a limited Brownian motion theory of particles with fluid memory effect, and calculating the water content quality of the cell; and obtaining the dry quality of the cell by two-dimensional integration within a cell profile based on a linear relationship between a non-water content density and a refractive index increment. The present application realizes non-invasive, non-contact and synchronous measurement of the water content quality and the dry quality of living cells.

The invention discloses an intermediate alloy for controlling microscopic residual stress of a large casting and a preparation method. The intermediate alloy comprises the nominal components of 0.6%-8% of Ti, 0.2%-3% of B and the balance Al and impurities. Wherein the mass ratio of Ti to B is (2-2.2): 1. The average size of TiB2 particles of the prepared intermediate alloy is 200-400 nm, and the particle size distribution is more uniform; the TiB2 particles are approximately equiaxed, so that stress concentration can be effectively avoided. The Brownian movement of the intermediate alloy added into an aluminum melt is violent, the particle dispersion effect is good, serious specific gravity segregation does not exist, and the regulation and control effect of TiB2 particles on the microcosmic residual stress can be effectively exerted. The intermediate alloy can be applied to a plurality of actual scenes such as high-pressure die casting size precision control, extrusion casting part hot crack control, low-pressure casting part surface defect and feeding control and the like, the casting production efficiency is improved, and the production cost is reduced.

The invention discloses a vaccine atomization method and a vaccine atomization machine in an animal breeding process, and the atomization method comprises the following steps: generating high-pressure gas by an air compressor, and cooling the high-pressure gas to be less than 37 DEG C and greater than 20 DEG C; introducing the vaccine solution and the cooled high-pressure gas into a two-fluid ultrasonic spray head at the same time, and spraying out molecules of vaccine aerosol particles with the particle size smaller than or equal to 15 microns; a suspension auxiliary agent is gasified into smog-shaped floating objects at a high temperature, and the smog-shaped floating objects are mixed with vaccine aerosol particles to form mixed fog capable of being suspended and diffused; the wind power is adjusted through a numerical control fan controlled by a microcomputer, and mixed mist with the particle size of 5-15 microns is selected to be blown out of a mist outlet pipeline. Normal-temperature atomization of vaccines is achieved, the atomized vaccines can diffuse and suspend in the air through Brownian motion for a long time and can be evenly distributed in the whole space of a closed place after a period of time, animals passively inhale a vaccine aqueous solution, and the purpose of inoculation is achieved.

This invention discloses a DNA triplet coding optimization method based on interaction forces. First, a fixed number of DNA triplet coding sequences are constructed as an initial population, and the fitness of the population is evaluated and ranked. Second, using the obtained DNA triplet coding sequences, optimization is performed through the sailfish algorithm and Brownian motion to obtain DNA triplet coding sequences with high fitness. Then, constraint alignment is used to determine whether to add them to the candidate solution set based on the constraints. Finally, high-quality DNA triplet coding sequences are output. The DNA triplet sequences generated by this invention have high stability and reversibility, and achieve efficient and automated sequence design, promoting the wider application of DNA triplet coding in nanotechnology.

The invention belongs to the technical field of measurement, and provides a method and a device for measuring the flow velocity of a microfluid, the method comprises the following steps: dispersing microspheres in a liquid to be measured to form a dispersion liquid, enabling the dispersion liquid to enter a microchannel, creating an optical trap by using optical tweezers (optical tweezers), and capturing a single microsphere; the method comprises the following steps: capturing a to-be-detected liquid in a microchannel, enabling the to-be-detected liquid to form a microfluid (microflow) in the microchannel after capturing so as to scour the captured microsphere, recording the movement track of the captured microsphere in the microfluid by using a quadrant detector, analyzing to obtain the characteristic frequency f of the movement, and calculating to obtain the flow velocity v according to a formula v = (f * d) / Sr in combination with the diameter d of the microsphere and the Sr. According to the method, the optical tweezers technology and the Karman vortex shedding flowmeter principle are combined and applied to microfluid flow velocity measurement, displacement of captured particles does not need to be measured, interference of Brownian motion can be effectively eliminated, and the method is simple, reliable, feasible and high in result accuracy.