80 results about "Mean pressure" patented technology

A method and apparatus for determining the mean arterial blood pressure (MAP) of a subject during tonometric conditions. In one embodiment, the apparatus comprises one or more pressure and ultrasound transducers placed over the radial artery of a human subject's wrist, the latter transmitting and receiving acoustic energy so as to permit the measurement of blood velocity during periods of variable compression of the artery. During compression, the ultrasound velocity waveforms are recorded and processed using time-frequency analysis. The time at which the mean time-frequency distribution is maximal corresponds to the time at which the transmural pressure equals zero, and the mean pressure read by the transducer equals the mean pressure within the artery. In another aspect of the invention, the ultrasound transducer is used to position the transducer over the artery such that the accuracy of the measurement is maximized. In yet another aspect of the invention, a wrist brace useful for measuring blood pressure using the aforementioned apparatus is disclosed.

An optical noninvasive vital sign monitor comprising a reflectance-type optical sensor within a pressurizable capsule retained by a headband, the capsule having an optically transparent or translucent inner wall adapted for placement against a subject's forehead. The optical sensor is mounted on the inside surface of the pressurizable capsule's inner wall, which contacts the subject's forehead during use, and includes a light source and a photodetector aimed toward the inside surface of the inner capsule wall. One embodiment of the vital sign monitor includes optical oscillometric circuit means responsive to an output signal from the optical sensor for determining systolic pressure, mean pressure and diastolic pressure during a transition in capsule pressure between a pressure greater than normal systolic pressure and a pressure less than normal diastolic pressure.

A device and method for maintaining a constant average pressure difference between the inlet and outlet of a pump for a body fluid, leading to an adequate flow for different pathological and physiological conditions, is described. The device and method allow for automatic adjustment of the pump operation to increase or decrease the flow rate of a body fluid to meet the physiological demand of the patient. The device and method also allow the physiological constraints on the pump to be accounted for, preventing suction and minimizing back flow of the body fluid. The device and method allow implicit synchronization of the pump with the natural regulatory mechanism for meeting patient's demand. The natural regulatory system continuously adjusts the parameters of the circulatory system to meet physiological demand for a body fluid. Maintaining constant pressure differential between the inlet and outlet of a pump, or a part of the body leads to the adaptation of the flow rate of the body fluid to physiological changes in response to the patient's clinical or physiological conditions.

An optical noninvasive vital sign monitor comprising a reflectance-type optical sensor within a pressurizable capsule retained by a headband, the capsule having an optically transparent or translucent inner wall adapted for placement against a subject's forehead. The optical sensor is mounted on the inside surface of the pressurizable capsule's inner wall, which contacts the subject's forehead during use, and includes a light source and a photodetector aimed toward the inside surface of the inner capsule wall. One embodiment of the vital sign monitor includes optical oscillometric circuit means responsive to an output signal from the optical sensor for determining systolic pressure, mean pressure and diastolic pressure during a transition in capsule pressure between a pressure greater than normal systolic pressure and a pressure less than normal diastolic pressure.

A system and method for monitoring changes in the pressure of a fluid line upstream of an infusion pump to determine when a fluid container has emptied, and to provide a signal indicating that the container needs replacement or replenishment. The difference between averaged pressures over separate time periods is monitored to determine when the fluid container is empty. The system and method are applicable to primary and secondary fluid container setups and can detect the point where the secondary has been emptied and the primary flow has resumed.

Provided is a non-invasive electronic method and apparatus for measuring blood pressure, in which the data is processed with an algorithm of non-linear fitting for recovering trend envelope of an oscillating PW by a firmware, so that the trend envelope of PW amplitude can be recovered accurately, and the obtained average pressure shows higher degree of agreement with the real situation in clinic. In this apparatus, a 3-way solenoid valve (20) is arranged between a cuff (10) and a first pressure sensor (30), wherein the common port of the 3-way solenoid valve (20) is connected with the first pressure sensor (30), the normally open port thereof connected with the cuff (10), and the normally closed port thereof connected with the air atmosphere during zeroing process. Moreover, an independent timing circuit (45) is provided additionally. In the measurement method of the present invention, the zeroing is performed with the help of the 3-way solenoid valve (20). Once a state of overtime or overpressure occurs, an air bump (50) is immediately closed, and a quick-deflation solenoid valve (60) is opened so that the pressure in the cuff (10) is released to ensure safe application.

The present invention discloses method and device for detecting pulse wave by means of cardiac symbol signal. Through detecting the temporal interval between the R wave and the pulse wave, obtain reference interval value, locating searched pulse wave amplitude with the reference interval value and obtaining reference pulse wave amplitude under different pressures, the mean pressure, the systolic pressure and the diastolic pressure are calculated by means of the ratio process. Compared with the available method to search pulse wave peak directly in the pulse wave signal, the present invention has raised anti-jamming capacity and raised blood pressure measuring accuracy especially in case of sports and arrhythmia.

Provided is a non-invasive electronic method and apparatus for measuring blood pressure, in which the data is processed with an algorithm of non-linear fitting for recovering trend envelope of an oscillating PW by a firmware, so that the trend envelope of PW amplitude can be recovered accurately, and the obtained average pressure shows higher degree of agreement with the real situation in clinic. In this apparatus, a 3-way solenoid valve (20) is arranged between a cuff (10) and a first pressure sensor (30), wherein the common port of the 3-way solenoid valve (20) is connected with the first pressure sensor (30), the normally open port thereof connected with the cuff (10), and the normally closed port thereof connected with the air atmosphere during zeroing process. Moreover, an independent timing circuit (45) is provided additionally. In the measurement method of the present invention, the zeroing is performed with the help of the 3-way solenoid valve (20). Once a state of overtime or overpressure occurs, an air bump (50) is immediately closed, and a quick-deflation solenoid valve (60) is opened so that the pressure in the cuff (10) is released to ensure safe application.

The invention discloses a method for determining retrograde condensation oil saturability in a depletion development sandstone condensate gas reservoir reservoir. The method comprises the following steps: 1, obtaining a core of the actual reservoir, and cleaning and drying the core; 2, testing the gas phase effective permeability Kegi under different oil saturation Soi conditions, and determining the values of the parameter a and the pameter b in the formula Soi=aln (kegi) +b; 3, preparing formation fluid samples; 4, restoring the core to the original reservoir state; 5, lowering the pore pressure in the core, and recording the core inlet end pressure, the outlet end pressure and the core outlet end output air volume; 6, calculating the gas phase effective permeability Kfegi under the mean pressure condition in the core depletion process; 7, calculating the retrograde condensation oil saturability Soi in the sandstone condensate gas reservoir under different pressure conditions. The method is reliable in principle, simple and applicable, influence of porous media, water saturation and condensate oil flowing is taken into consideration comprehensively, and wide market prospect is achieved.

A noninvasive vital signs monitoring device uses a sensor which is capable of providing data for calculating pulse rate, blood pressure (for example, systolic, diastolic, and / or mean pressure) and blood oxygen saturation. In some embodiments, the sensor is also capable of providing data for calculating tissue perfusion. Optionally, a temperature sensor may be included as well.

The invention discloses an individual adaptive pressure increasing and decreasing control method for an electronic sphygmomanometer. The method includes: continuously inflating a cuff sleeved on an upper arm for pressure increasing; detecting pulse wave signals and cuff pressure signals; calculating mean pressure Pv and heart rate S according to the pulse wave signals during pressure increasing, calculating systolic pressure Ps according to the mean pressure Pv, and setting the maximum valve Pm of cuff pressure increasing; when the pressure of the cuff reaches the maximum value Pm, by a control air valve, performing individual adaptive constant-speed pressure decreasing until pressure decreasing is completed and the control air valve is completely opened to empty air. By the individual adaptive pressure increasing and decreasing control method for the electronic sphygmomanometer and the electronic sphygmomanometer, high-quality pulse wave signals with moderate pulse waves, reasonable amplitude and evident envelop features, a premise is provided for further identification and determining of blood pressure parameters, and comfortableness of a to-be-tested person is improved during the whole test. In addition, the method is high in individual adaptive measuring capability.

A bearing surface (50) opposing a movable guide (21) of a hydrostatic bearing has a gas supply hole (52) which has an orifice with a diameter smaller than that of the outer shape of the bearing. Each of hydrostatic bearings (14, 24) incorporates a poppet valve (53) which can seamlessly change the flow resistance in the gas supply hole (52), an actuator unit (55) for linearly driving the poppet valve (53), and a guide mechanism (58) which guides the poppet valve (53) so as to set the poppet valve (53) in linear motion. The actuator unit (55) has, for example, coils (56) arranged on the movable side (the base of the poppet valve (53)) and permanent magnets arranged on the fixed side (a portion opposing the base of the poppet valve (53)). With this arrangement, the poppet valve (53) can be driven at high speed and high precision. The poppet valve (53) is driven in accordance with a command from a controller (51). A pressure (Ps) is applied to the poppet valve (53) as the back pressure. The pressure (Ps) is restricted by the poppet valve (53) and a bearing clearance and becomes a bearing mean pressure (p).

A pneumatic ventilation system delivers high amplitude, low frequency oscillatory flows while maintaining the load impedance at a specified mean pressure, thereby accurately controlling mean airway pressure, oscillation amplitude, and frequency content allowing use in applications to optimize high frequency ventilation protocols in patients. The pneumatic ventilation system includes a pneumatic pressure oscillator based on a proportional solenoid valve to provide forced oscillatory excitations to a respiratory system over a bandwidth suitable for mechanical impedance measurements and high frequency ventilation.

A preferred embodiment EGR valve permits exhaust gas to be induced into the intake line downstream of the compressor, while minimizing the need to reduce the size of the turbocharger. The preferred embodiment EGR valve exploits variations around the mean pressure in the EGR passage created by the engine cycle by selectively opening when the pressure in the EGR valve exceeds the pressure in the intake line. Thus, exhaust gas is recirculated even when the engine is running near torque peak. The preferred embodiment EGR valve also exploits the higher mean pressure in the exhaust line relative to the intake line at higher engine speeds by remaining open, in order to minimize the energy consumed in opening and closing the EGR valve.

The invention relates to a method of operating an internal combustion engine operated on gasoline type fuels, more specifically on gasoline, wherein ignition of the fuel-air mixture is initiated spontaneously in at least one operational range of the engine, preferably in the part load range, and wherein a stratified charge is produced in the combustion chamber, preferably in the higher load range. In order to achieve in the simplest possible manner high exhaust quality for an internal combustion engine operated on fuel with poor ignition characteristics in the range of higher mean pressures as well there is provided that combustion is initiated by spontaneous ignition of the fuel in the full load range as well and that preferably the in-cylinder charge temperature is controlled throughout the load range by way of internal exhaust gas recirculation and that, in the full load range, the start of fuel injection occurs after top dead center.

A preferred embodiment EGR valve permits exhaust gas to be induced into the intake line downstream of the compressor, while minimizing the need to reduce the size of the turbocharger. The preferred embodiment EGR valve exploits variations around the mean pressure in the EGR passage created by the engine cycle by selectively opening when the pressure in the EGR valve exceeds the pressure in the intake line. Thus, exhaust gas is recirculated even when the engine is running near torque peak. The preferred embodiment EGR valve also exploits the higher mean pressure in the exhaust line relative to the intake line at higher engine speeds by remaining open, in order to minimize the energy consumed in opening and closing the EGR valve.

An image forming apparatus comprising a fixing roller, an endless fixing belt engaged at least with the fixing roller, and a pressing roller opposite to the fixing roller with the endless fixing belt between them; wherein the image forming apparatus is equipped with a pressure changing member for changing the mean pressure on a second pressing area against which the pressing roller pressed the fixing roller via the fixing belt in the pressure area formed by the pressing roller.

A method is provided for predicting the likelihood of cavitation damage occurring on a surface of a hydrodynamic component. The method may include creating a computational fluid dynamics (CFD) simulation of the hydrodynamic component, wherein creating the CFD simulation includes simulating a fluid proximal to the surface of the hydrodynamic component. The method may also include selecting a location on the surface of the hydrodynamic component, wherein the selected location is exposed to the simulated fluid. The method may further include determining the mean pressure and standard deviation, the standard deviation of the rate of change in pressure, the mean void percentage and standard deviation, and the standard deviation of the rate of change in void percentage for the fluid at the selected surface location. The method may also include analyzing at least one of the mean pressure and standard deviation, the standard deviation of the rate of change in pressure, the mean void percentage and standard deviation, and the standard deviation of the rate of change in void percentage for the fluid at the selected surface location to predict the likelihood of cavitation damage occurring at the selected surface location.

A method and an apparatus for calculating blood pressure with signal transformation are provided, wherein said apparatus comprises: a pressure sensor, a pressure and pulse wave amplification circuit, an A / D converter, a microprocessor, a control circuit, an air bump and a valve component connected with the cuff gas circuit, a signal processing module and a ratio analysis module; and the method includes the steps of carrying out signal transformation of a time sequence of a sampled PW digital signal, calculating a maximum amplitude value and a corresponding frequency value based on the transformed signal, taking the maximum amplitude value as a amplitude value under the present pressure, carrying out continuously signal transformation of the time sequences of the PW digital signals at different pressure in order to constitute a PW amplitude-pressure curve and obtain an average pressure and a corresponding pulse rate from the PW amplitude-pressure curve, and finally calculating the systolic pressure and diastolic pressure with ratio method. With the method and apparatus according to the present invention, the measurement error can be reduced in case of the shiver, muscular fibrillation and the like of the human body being examined, and the measurement accuracy of blood pressure can be improved.

A method for the automated setting-up of an injection molding machine, the machine for manufacturing injection molded parts and including an injection screw and a configurable injection velocity, including the steps of: manufacturing one of more parts with the machine; determining an injection pressure profile by measuring injection pressure as a function of elapsed injection time with the machine configured with a substantially constant, desired injection velocity; measuring injection velocity as a function of elapsed injection time and determining a profile of the measured injection velocity; defining a mean pressure profile from the pressure profile in a regime of substantially constant measured injection velocity profile; adjusting the velocity profile over at least a portion of an injection velocity phase in response to the pressure profile to reduce differences between the pressure profile and the mean pressure profile, thereby tending to lessen irregularities in the pressure profile.

The invention provides a method for measuring blood pressure, specifically comprising steps of automatically pumping an oversleeve with a gas pump, 10-20mmHg for pumping each time, detecting to identify maximal value of pulse wave, the pressure is mean pressure; going on pumping to measure pulse, when pulse wave intensity is 50% of the maximal value of pulse wave, the pressure is systolic pressure; calculating diastolic pressure according to the oscillogram obtained by measuring; pumping until the pressure is 10-20mmHg higher than the systolic pressure, then gradually discharging gas to measure systolic pressure, 13-5mmHg for discharging each time, during the discharging process, using an optical pulse detecting device and a sonic pulse detecting device to correct the systolic pressure, when the optical pulse detecting device has detected optical signals and the sonic pulse detecting device has detected sound signals, the pressure is the corrected systolic pressure. Advantage of the method lies in that noninvasive blood pressure measurement is more accurate, and measuring precision and consistency are improved.

The present invention consists in a method of plasma treatment of a semiconductor substrate in a process chamber connected to a vacuum line via a valve, said treatment including a plurality of cycles comprising at least one etching step during which an etching gas is introduced alternating with at least one passivation step during which a passivation gas is introduction into said chamber, which method includes the following operations:(a) a reference pressure Pref is defined at which it is wished to effect the treatment,(b) the position of the valve is fixed during the first etching step,(c) the pressure in the process chamber is allowed to stabilize during n cycles,(d) the pressure in the process chamber is measured during the etching step during m cycles, with m at least equal to 2, and an average pressure value Pc is calculated from the measurements effected,(e) after n+m cycles, the position of the valve is corrected with a view to obtaining a pressure in the process chamber that approximates the reference pressure value Pref,(f) the steps (c) to (e) are repeated until the calculated average pressure Pc is substantially equal to the reference pressure value Pref so that it is no longer necessary to correct the position of the valve.

A method and apparatus is provided for estimating the mean pressure in a compressible fluid strut. A database is employed containing values for mean pressure variation corresponding to a specific combination of motor speed and flow demand, and may also account for strut temperature. The flow demand and the speed of the motor are determined, and the mean variation corresponding to the determined combination of motor speed and flow demand is selected. The estimation of strut mean pressure is updated with the selected mean pressure variation. In this way, costly pressure sensors are eliminated as well as the complicated control algorithms which are used therewith.

A blood pressure detection apparatus includes a pressure sensor (12), a press mechanism (10) that applies pressure to a blood vessel by pressing a living body, and can gradually decrease the pressure, and a blood pressure calculation section that determines the pressure when a given waveform pattern appears in a waveform of pulse waves obtained by the pressure sensor to be a maximal blood pressure, determines the pressure when the waveform has a maximum amplitude to be a mean blood pressure, and calculates a minimal blood pressure using the maximal blood pressure and the mean blood pressure.

A system and method for deriving information on disease in vascular segments for example mean pressure, drop in mean pressure and / or hydraulic resistance, from such measured waveforms is described. The waveforms can, for example, be measured non-invasively using Doppler ultrasound or magnetic resonance techniques. Form Factors (Vff, Pff) for the velocity waveform and the central arterial pressure are determined. Lesions may be detected and located using the estimated non-invasive hemodynamic information

The invention discloses a Korotkoff sound blood pressure measurement and signal analysis method based on wavelet denoising. The method comprises the following steps: collecting the Korotkoff sound signal; storing the Korotkoff sound signal to a preprocessing module; The sound signal is denoised; the Korotkoff sound blood pressure signal is extracted from the denoised signal; and the systolic blood pressure, diastolic blood pressure and average pressure of the Korotkoff sound blood pressure signal are automatically detected. The present invention realizes the preprocessing and automatic detection of Korotkoff sound blood pressure measurement automatically at one time, and makes up for the deficiency in the traditional Korotkoff sound blood pressure measurement. The preprocessing, signal extraction and automatic detection can reduce the error caused by the subjective factors of doctors. Improve the accuracy, work efficiency and repeatability of Korotkoff sound blood pressure measurement, and provide a more accurate basis for the public's blood pressure measurement.

The invention relates to an ultralow-power-consumption ultra-small-volume in-vivo implantation type blood pressure signal measuring and monitoring method and device. The device is in the form of a capsule. An electromagnetic coupling energy supply system and a rechargeable technology are utilized; a special blood pressure sensing system is utilized to complete blood pressure signal transfer, ultralow-power-consumption signal acquisition and wireless reception and transmission; an in-vitro signal data receiving system completes wireless receiving and conditioning of the signal; and a signal data processing and analyzing system is used for data storage and analysis via an interface module. The invention can monitor the contractive pressure and diastolic pressure in a long-term, safe, stable and direct way in a natural physiological state to acquire mean pressure, pulse rate, blood volume, blood flow and other related parameters, thereby completing display, storage and printing output of blood pressure waveform. The invention is widely used in pharmacological and pathological tests, is effectively used in researching cardiovascular disease, hypertension and diabetes, judging curative effects of related therapeutic drugs, monitoring blood pressure during and after surgeries for diagnosing and treating various diseases, and is applicable to other research fields.