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543 results about "Self-oscillation" patented technology

Self-oscillation is the generation and maintenance of a periodic motion by a source of power that lacks any corresponding periodicity. The oscillator itself controls the phase with which the external power acts on it. Self-oscillators are therefore distinct from forced and parametric resonators, in which the power that sustains the motion must be modulated externally. In linear systems, self-oscillation appears as an instability associated with a negative damping term, which causes small perturbations to grow exponentially in amplitude. This negative damping is due to a positive feedback between the oscillation and the modulation of the external source of power. The amplitude and waveform of steady self-oscillations are determined by the nonlinear characteristics of the system. Self-oscillations are important in physics, engineering, biology, and economics.

Self-excited oscillation type high power LED constant-current driving circuit

The invention provides a self-oscillation type high power LED constant-current drive circuit with low cost, high reliability and stability and high drive efficiency, the circuit comprises a rectifier and filter circuit, a switching circuit, a steady voltage constant current output circuit, a transformer, a self-oscillation type pulse width modulation signals generating circuit and a current feedback obstruction circuit, wherein the rectifier and filter circuit accesses commercial power into rectification, changes the commercial power into direct current, and then outputs commercial power to the switching circuit to switch in a self-oscillation type with high frequency, then high frequency voltage of the steady voltage constant current output circuit is transformed into direct voltage through the transformer to drive the LED, simultaneously sampling current signals produces jam signals through the current feedback obstruction circuit to control the switching circuit to work, the circuit does not adopt any driving chips and only uses fewer common individual devices to form a self-oscillation type structure to drive the switching circuit and to combine current feedbacks, which realizes constant current driving of the high power LED.
Owner:NANTONG LIWANG MACHINE TOOL +1

Waterpower pulse cavitation jet well drilling device, method and drill bit

The invention discloses a hydraulic pulse drilling device with cavitation jet, which comprises a columnar body, wherein a fluid inlet section is provided at one end of the body, a fluid outlet section is provided at the other end of the body, and a fluid diversion portion for deviating the flow direction of the fluid, a pulse generator allowing the continuous fluid to generate pulse and a self-oscillation portion for allowing the fluid with pulse to generate resonance oscillation are sequentially provided between the fluid inlet section and fluid outlet section. The invention also discloses a self-resonating cavitation jet nozzle for drilling head, which improves the rock breaking effect of drilling head and rock cleaning effect at well bottom. The invention also discloses a hydraulic pulse drilling method with cavitation jet, which comprises during drilling work, converting continuous and stable fluid flow for impacting well bottom to pulse resonance flowing fluid; and injecting the pulse resonance flowing fluid into relatively static fluid to generate cavitation phenomena. The impact of well bottom with oscillating pressure reduces clip hold down effect, improves the rock cleaning and rock breaking capacity by jetting, and saves drilling cost.
Owner:CHINA UNIV OF PETROLEUM (BEIJING)

High-pressure self-oscillation oscillating impulse jet flow nozzle with continuous adjustable cavity length

The invention discloses a high-pressure self-oscillation oscillating impulse jet flow nozzle with continuous adjustable cavity length. The high-pressure self-oscillation oscillating impulse jet flow nozzle comprises an inlet nozzle, an adjusting ring, a base and an outlet nozzle, wherein the base is an inner hollow cylinder; the inner cavity of the cylinder is a cylindrical oscillating cavity; the upper end of the inlet nozzle is connected with a high-pressure pipe by external threads arranged on the cylindrical face of the end part of the upper end; the middle of the inlet nozzle is spirally connected with inner ring threads of the adjusting ring by external threads arranged on the outer cylindrical face of the middle; the lower end of the inlet nozzle is spirally screwed into the oscillating cavity of the base; the base is fixedly connected with the adjusting ring and the outlet nozzle respectively by screws, through holes formed in the upper and lower bottom faces of the base, a through hole formed in the adjusting ring and a through hole formed in the outlet nozzle. The high-pressure self-oscillation oscillating impulse jet flow nozzle with the continuous adjustable cavity length has the advantages that aiming at different working pressures, the cavity length of the oscillating cavity can be continuously adjusted by rotating the base, and thus the continuous jet flow is changed into strong impulse jet flow; each part of the nozzle is easily processed, and the replacement is convenient.
Owner:WUHAN UNIV

Optimized cesium-light-pump weak magnetic detection device

The invention relates to an optimized cesium-light-pump weak magnetic detection device. In the optimized cesium-light-pump weak magnetic detection device, a non-magnetic-effect thermostatic controller enables a cesium spectrum lamp and a cesium sample absorbing bulb to be in the constant-temperature steam state, a radio frequency source stimulates the cesium spectrum lamp to emit light, and the light is converted into left handed circular polarization light to illuminate the cesium sample absorbing bulb, and focused on a photoelectric detector through a convex lens; a magnetoresistive sensor magnetic measuring module assists in measuring the value of a geomagnetic field of the position where the device is located, the range of strength is judged through an embedded type processing terminal module, and a self-oscillation module is controlled in a segmentation mode; photomagnetic resonance signals of the cesium sample absorbing bulb are detected by a low-noise photoelectric conversion circuit and simulate a high-frequency coil on the cesium sample absorbing bulb after being amplified and dephased so as to constitute a self-oscillation circuit, and Larmor signals are output; a Larmor signal measuring module and a big-dipper / GPS locating module are used for accurately measuring the value of the geomagnetic field of the position where the device is located. According to the optimized cesium-light-pump weak magnetic detection device, by means of the method achieving auxiliary magnetic field measurement, subband control, accurate frequency measurement and dual-mode locating, detection accuracy and reliability of the device are guaranteed.
Owner:WUHAN UNIV OF TECH

Out-of-plane frequency method for testing cable force of planar cable rod system

InactiveCN101893497ASolve the cable force testResolve detectionTension measurementElement modelSelf-oscillation
The invention relates to an out-of-plane frequency method for testing the cable force of a planar cable rod system, which discloses an out-of-plane frequency method based on the cable force of a pulling cable of an out-of-plane self-oscillation frequency testing planar cable rod system and belongs to the fields of cable force monitoring, state (parameter) identification, health monitoring and the like of the construction phase and the use phase of a cable structure. The method is based on the cable force of the pulling cable of the out-of-plane self-oscillation frequency testing planar cable rod system, and continuous short cables in the planar cable rod system are converted into an out-of-plane long cable, the cable force is determined by measuring the out-of-plane self-oscillation frequency and establishing a cable force-out-of-plane self-oscillation frequency relation formula, and the method concretely comprises the following steps of: 1. carrying out the modal analysis of the finite element model of the planar cable rod system, and determining the out-of-plane calculated length; 2. measuring the out-of-plane self-oscillation frequency of the planar cable rod system; 3. identifying the out-of-plane bending rigidity according to the measured multistage out-of-plane self-oscillation frequency; 4. establishing the cable force-out-of-plane self-oscillation frequency relation formula; and 5. calculating the cable force.
Owner:SOUTHEAST UNIV

Self-oscillation pulsed liquid-gas jet pump

InactiveCN102865256AImprove Jet Pump EfficiencyWell mixedJet pumpsMachines/enginesSelf-oscillationSpray nozzle
The invention relates to a self-oscillation pulsed liquid-gas jet pump. The jet pump comprises an upper nozzle, a self-oscillation cavity, a collision body, a lower nozzle, a suction chamber, a throat pipe and a diffusion tube, wherein the upper nozzle, the self-oscillation cavity, the collision body and the lower nozzle are connected sequentially to form a self-oscillation pulsed jet nozzle; after passing through the self-oscillation pulsed jet nozzle, a main jet flow of high-pressure liquid is modulated into a pulsed jet flow and enters the suction chamber of a liquid-gas jet pump; and gas is introduced under the action of jet turbulent diffusion, and boosted and exhausted through the diffusion tube after mixing and energy exchange in the throat pipe. The self-oscillation pulsed liquid-gas jet pump has the advantages that the self-oscillation pulsed jet nozzle and the liquid-gas jet pump are combined, and the main jet flow is changed into pulsed jet flow through the self-oscillation pulsed jet nozzle, so that the mass transfer capability of the main jet flow is improved, and the efficiency of the liquid-gas jet pump is improved. The device is not provided with a motion part, simple in structure and reliable in operation, and is suitable for waste gas absorption and treatment, oil and gas exploitation, vacuumization, aeration and other application situations.
Owner:SHANGHAI UNIV

Multifunctional self-oscillation flow jet flow drill

The invention relates to a multifunctional self-oscillation jet drill bit. The prior similar product not only has shallow drilling depth and complex structure but also has large resistance loss and short service life of a drill bit, can not repeatedly switch drilling and groove cutting during the drilling process, and limits the application scope. A crushing blade and a valve body are arranged inside a cutting head body of the drill bit; a first offsetting spring in the valve body is matched with a valve core A in the form of sliding; a valve core B is matched with a second offsetting spring for operation under the action of a lined ring, a washer and the valve body together; and the valve core and a limber hole of the valve body are matched for use with a self-oscillation nozzle. The multifunctional self-oscillation jet drill bit adopts high-pressure water as power to realize repeated switching between drilling and groove cutting of coal seam and terrane, not only has a simple structure and is flexible to switch but also can promote development of coal seam fissure through oscillation jet generated by the nozzle, strengthens the permeability of the coal seam, improves the gas extraction rate, particularly has obvious effect on low-permeability coal seam, and widely promotes and applies the fluid technology of the high-pressure water in the fields of drilling and gas extraction of the low-permeability coal seam.
Owner:CHONGQING UNIV
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