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553 results about "PULSE PRESSURE DECREASE" patented technology

The pulse pressure increases with exercise due to increased stroke volume, healthy values being up to pulse pressures of about 100 mmHg, simultaneously as total peripheral resistance drops during exercise.

Radar moving target radon-fractional Fourier transform long-time phase-coherent accumulation detection method

ActiveCN103176178AEffective accumulationImprove complex (noise) ratioWave based measurement systemsRadar signal processingConstant false alarm rate
The invention relates to a radar moving target Radon-fractional Fourier transform (RFRFT) long-time phase-coherent accumulation detection method, and belongs to the technical field of radar signal processing and detection. The radar moving target Radon-fractional Fourier transform long-time phase-coherent accumulation detection method includes steps of 1), performing range demodulation and pulse pressure for radar echo to complete intra-pulse accumulation; 2), initializing parameters; 3), completing long-time inter-pulse phase-coherent accumulation by RFRFT compensation distance and Doppler frequency migration; 4), traversing all search parameters and creating a distance-RFRFT domain detection unit graph; 5), performing constant false alarm rate detection for the detection unit graph; and 6), estimating movement parameters of a target and outputting movement point traces. The radar moving target Radon-fractional Fourier transform long-time phase-coherent accumulation detection method has the advantages that amplitude information and phase information of the echo of the moving target are simultaneously utilized for long-time phase-coherent accumulation, the distance and the Doppler frequency migration in a long-time accumulation procedure are compensated, background clutter and noise are effectively suppressed, an accumulation gain is increased, dim moving targets in the heavy cluster can be detected, the movement point traces of the target can be acquired, and the method has popularization and application value.
Owner:NAVAL AVIATION UNIV

Method for extracting gas in low air permeability coal layer by pulse fracture anti-reflection

The invention relates to a method for extracting gas in low air permeability coal layer by pulse fracture anti-reflection, comprising the following steps: firstly using the blast-proof pulse-type coal layer high pressure water injector with adjustable frequency and pressure from the coal layer, high tunnel or low tunnel; using the pulse water effect generated by the periodical change of high pressure pulse water inside the drill hole of coal body, wherein the maximum pulse pressure is 35 MPa, the flow is about 300 L / min, and the pulse frequency is 0-1460 times / min; forcing the macroscopic fracture in the coal layer to be expanded and communicated; promoting the micro-pore fracture to be formed and extended; forming a new regeneration fracture net; providing a permeable channel of water inthe coal layer so as to achieve the effects of improving the mechanical property of the coal body, reducing the stress of the coal body in front of the working face and improving the discharge rate of the gas. Through the method, the pressure releasing range of the coal layer is enlarged, the whole pressure is adequately released, the radius of influence range of fracture can reach 10-40 m, and the air permeability of the coal body can be improved by 100-1000 times; and the method is simple, easy to operate and good in effect.
Owner:CHINA UNIV OF MINING & TECH

Experimental device and method for pulse hydrofracture transforming of shale gas storing layer

ActiveCN103196762AMonitor developments in real timeGenerating type of real-time monitoringSurface/boundary effectMaterial strength using repeated/pulsating forcesImpulse frequencyFracturing fluid
The invention relates to an experimental device and method for pulse hydrofracture transforming of a shale gas storing layer. The experimental device comprises a high pressure water pump, a fracturing fluid pond, a filtering device, a waterpower pulse generating device, a triaxial stress loading device, a pressure sensor, a sound emission device, a throttle valve, an overflow valve, a data collection recording system and a core test specimen. The device provided by the invention can simulate the operating environment of a shale sample under main operating parameter such as different pulse pressures and impulse frequencies on a certain confining pressure condition; moreover, the device can monitor a space-time developing rule of cracks and can test permeability change before and after fracture in real time; therefore, an experimental platform is provided for researching pulse hydrofracture of a shale gas storing layer. The experimental device provided by the invention has strong practicality, is easy to assemble, convenient to operate, is compact in structure, and can better imitate fracture damage and permeability change mechanism of a shale sample of the shale gas storing layer under the actions of static pressure and pulse hydrofracture.
Owner:CHONGQING INST OF GEOLOGY & MINERAL RESOURCES

Missile-borne SAR sub-aperture forward squint high-order nonlinear chirp scaling imaging method

The invention belongs to the field of radar signal processing, and discloses a missile-borne SAR sub-aperture forward squint high-order nonlinear chirp scaling imaging method. According to the method, missile-borne SAR forward squint high-order nonlinear chirp scaling imaging is achieved through sub-aperture data, and the method can be used for SAR imaging of airborne platforms or missile-borne platforms. The method mainly includes the steps of firstly, conducting distance pulse pressure and time domain walking correction on an echo signal; secondly, converting the signal into the two-dimensional frequency domain, conducting frequency domain migration correction and secondary compression, and compensating for the high order phase in the orientation direction; thirdly, leading high-order nonlinear chirp scaling disturbance factors into the orientation frequency domain, and correcting the space variability of the Doppler frequency modulation and the high-order terms in the orientation direction; fourthly, focusing an image on the orientation frequency domain through spectrum analysis. The method solves the problem of decoupling of distance orientation and the orientation focus depth problem caused by time domain walking correction, and the method can meet the requirements for different scenes and high resolution and can be used for the field of ground mapping and other fields.
Owner:XIDIAN UNIV

Method of operating a linear ion trap to provide low pressure short time high amplitude excitation with pulsed pressure

Methods for fragmenting ions in an ion trap are described. These methods involve a) selecting parent ions for fragmentation; b) retaining the parent ions within the ion trap for a retention time interval, the ion trap having an operating pressure of less than about 1×10-4 Torr; c) providing a RF trapping voltage to the ion trap to provide a Mathieu stability parameter q at an excitement level during an excitement time interval within the retention time interval; d) providing a resonant excitation voltage to the ion trap during the excitement time interval to excite and fragment the parent ions; e) providing a non-steady-state pressure increase of at least 10% of the operating pressure within the ion trap by delivering a neutral gas into the ion trap for at least a portion of the retention time interval to raise the pressure in the ion trap to a varying first elevated-pressure in the range between about 6×10-5 Torr to about 5×10-4 Torr for a first elevated-pressure duration; and f within the retention time interval and after the excitement time interval, terminating the resonant excitation voltage and changing the RF trapping voltage applied to the ion trap to reduce the Mathieu stability parameter q to a hold level less than the excitement level to retain fragments of the parent ions within the ion trap. The excitation time interval and the first elevated-pressure duration substantially overlap in time.
Owner:MDS ANALYTICAL TECH A BUSINESS UNIT OF MDS +1

High resolution spotlight SAR self-focusing imaging method based on two-dimensional self-focusing

The invention belongs to the radar technology field, discloses a high resolution spotlight SAR self-focusing imaging method based on two-dimensional self-focusing and mainly solves a problem that excellent focusing of a uniform imaging area can not be realized through a self-focusing algorithm in the prior art. The method comprises steps that an original echo signal of a target is received, after distance pulse pressure of the echo signal is carried out, crude envelope error and phase error compensation for the signal is carried out; distance direction FFT and azimuth solution linearity frequency modulation operation and two-dimensional interpolation operation are carried out; after distance direction IFFT of a result after two-dimensional interpolation is carried out, distance migration of a distance skipping unit is evaluated, and envelope error correction is accomplished; V non-superposed distance sub blocks are formed through uniform division along the distance direction, and a phase error of each sub block is evaluated; corresponding weights of distance units are respectively calculated, distance errors of the distance sub blocks are evaluated respectively, space-variant error evaluation is accomplished, azimuth direction IFFT of the data after correction is carried out, and thereby SAR images having the excellent focusing effect are acquired.
Owner:XIDIAN UNIV

Body feeling network-based sleeveless driven pulse pressure measurement and automatic calibration device

The invention discloses a body feeling network-based sleeveless driven pulse pressure measurement and automatic calibration device. The device comprises a body feeling network node for acquiring a heart pulsation related signal from the body surface of a user, a body feeling network node for measuring a transmission distance between the heart and a heart pulsation related signal acquisition point, a body feeling network node for measuring angle change of the heart pulsation related signal acquisition point relative to the position of the heart, and a control and calculation central pivot. The body feeling network nodes of the device are distributed on the body surface of the user, so the device is simple and convenient to mount, has no injury to the human body and does not need to inflate sleeve straps in the calibration and measurement processes; the device realizes the communication between the nodes and the control and calculation central pivot in a wireless mode, is convenient to carry, does not affect the daily life and can be continuously used for long time; and simultaneously, the device extracts multiple physiological parameters aiming at different individuals and different physiological states to automatically finish calibration, and has high estimation accuracy of blood pressure, comprehensive monitoring and broad application range.
Owner:THE CHINESE UNIVERSITY OF HONG KONG

Radar slightly-moving target detection method based on Radon-linear canonical ambiguity function

The invention relates to a radar slightly-moving target detection method based on a Radon-linear canonical ambiguity function (RLCAF) and belongs to the technical field of radar signal processing and detection. The radar slightly-moving target detection method based on the RLCAF comprises the following steps that (1) demodulation and pulse pressure are conducted on a radar echo in the distance direction so that in-pulse accumulation can be completed; (2) the type of a target to be detected is predicted, and parameters are initialized; (3) the distance and Doppler migration are compensated through the RLCAF and signal energy of a slightly-moving target is accumulated; (4) the parameters are traversed and searched, an RLCAF domain detection unit figure is established, and constant false-alarm detection is conducted; (5) target moving parameters are estimated and moving trace points are output. According to the radar slightly-moving target detection method based on the RLCAF, the advantages of an ambiguity function and the advantages of linear canonical transformation are combined, non-uniform velocity translational motion target signals or turning target signals can be flexibly matched and accumulated in a clutter background, the signal-to-clutter ratio is improved, range migration can be compensated through the extraction of a target observation value in a distance-slow-time plane, phase-coherent accumulation for a long time is completed, the detection capacity of radar to the slightly-moving target is improved, and therefore the radar slightly-moving target detection method based on the RLCAF is wide in applicability.
Owner:NAVAL AVIATION UNIV
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