33 results about "Parabolic function" patented technology

A method is disclosed for moving, isolating and/or identifying particles in a sample by placing said sample in a spatially varying electrical field wherein the spatially varying electrical field is following a mathematical nonmonotonous function, selected from the group consisting of linear, hyperbolic, parabolic, parabolic functions or y~xp/q and combinations thereof wherein p q means an integer. Also various devices are disclosed for performing the method.

There is provided an artificial cardiac or heart valve, more particularly a flexible leaflet heart valve used to replace natural aortic or pulmonary valves of the heart in which the leaflet geometry is defined by a parabolic function and a method of manufacturing said artificial cardiac valves. In addition, there is provided leaflets which have geometry defined by a parabolic function.

An automatic test system that includes low cost and accurate circuitry for generating sinusoidal signals. Each sinusoidal signal generator produces a series of digital values approximating a sine wave. These values are computed, avoiding the need for large memories to store tables representing sine waves. Inaccuracies in the representation of the sine waves do not impact the accuracy of the resultant sine wave because circuitry used to correct for non-linearity errors in a digital-to-analog converter is programmed to also correct for errors introduced by approximating a sine wave with a computed function. A simple parabolic function may be used to compute approximations of a sine wave.

The invention discloses a precise control method of a linear motion module. A motion control method based on S-shaped speed curve planning and synchronous planning of parabolic functions is adopted to precisely control the linear motion module; an acceleration maximum value and a speed maximum value of each motion shaft of a truss manipulator are input; an initial pose and a target pose of the truss manipulator are given to obtain a displacement variation of each motion shaft of the manipulator; time function nodes of each motion shaft are calculated; longest time nodes are selected as unified planning nodes to calculate actual maximum speed and maximum acceleration of each motion shaft; displacement, speed and acceleration functions at an acceleration phase, a deceleration phase and a constant-speed phase are respectively calculated according to the actual maximum speed and the maximum acceleration of each motion shaft; and the displacement of each motion shaft or discrete points on speed curves are output. The method can prevent the manipulator vibration or noise problem caused by sudden change of the speed or the acceleration, guarantees the motor motion precision, and can control the motion trajectory.

The invention discloses a phonological tone changing method and a phonological tone changing device. A time delay factor corresponding to the current time is calculated according to a tone changing function changing along with the time change; and the voice to be processed is subjected to time delay processing according to the time delay factor so as to achieve the special sound effect of 'foreign tone'. Compared with the prior art, the tone changing method adopts a function value changing along the time as a tone changing amplitude, instead of adopting fixed amplitude to raise or fall the tone, so as to achieve the effect of changing the sound into 'foreign tone'; and the sine function in the tone changing function is simulated by adopting a parabolic function, so that the fixed-point processing is simple, and the scheme of the invention is convenient to process on fixed-point digital signal processing-based chips.

The invention provides a three-phase voltage type PWM rectifier startup inrush current suppression method, relates to the technical field of three-phase voltage type PWM rectifier startup, and solves the problems of burnout of electric inductors, burnout of the insulating layer of leads and damage to switching device caused by inrush current generated in the startup process of an existing PWM rectifier or the phenomena that control is complex and the effect is poor and damage caused by inrush current on the rectifier cannot be completely eliminated. A superposition signal of input voltage V'dc and a parabolic function y1, a superposition signal of voltage V'dc and a ramp function y2, a superposition signal of voltage V'dc and a parabolic function y3 and a superposition signal of voltage V'dc and DC stable voltage Vref are inputted to the DC bus voltage given end of a three-phase voltage type PWM rectifier in turn so that suppression of inrush current generated in the startup process of the three-phase voltage type PWM rectifier can be realized. The three-phase voltage type PWM rectifier startup inrush current suppression method is suitable for suppressing startup inrush current of the three-phase voltage type PWM rectifier.

The invention discloses a centrifugal pump with a swirl sprayer engine directly connected with a high-speed function vane wheel and an even-spinning labyrinth. Rotation inertia connected with a driving shaft is improved; a vibration attenuation and noise reduction protection cover is adopted; a four-stroke or two-stroke engine is directly connected with a vane wheel of which two ends are planes and an inner sunken bottom is a parabolic function surface; two sides of a vane of the vane wheel are included angle function surfaces, the inner parts of the two sides of the vane are thin, the outer parts of the two sides of the vane are thick, and end face labyrinth sealing is realized on the back face of the vane wheel; the bidirectional horizontal even-spinning labyrinth sealing is used, so that the sealing friction loss is reduced; a shell with an eccentric outlet and northern-hemisphere anticlockwise streamline ribs is used, so that the friction loss is reduced; a volute with an outlet chamfer and a northern-hemisphere anticlockwise non-archimedes function line is used, so that the stroke loss is reduced; and ribs or vanes are arranged on the back face of the vane wheel, so that the pressure on the back face of the vane wheel is reduced; or planar spiral slots with opposite directions are respectively formed on the surface of the back face of the vane wheel and the inner wall surface of the vertical shell close to the vane wheel. The centrifugal pump has two functions of end face labyrinth sealing and axial balance.

The invention provides an involute gear shaping grinding wheel calculating method which can calculate the shaping euqation of the formed grinding wheel based on a preset two-order transmission error so as to quickly determine the shaping amount of the gear. The involute gear shaping grinding wheel calculating method is used for calculating a shaping equation of the shaping grinding wheel for grinding an active wheel and a slave wheel according to the preset the two-order transmission error between the active wheel and the slave wheel. The method comprises steps of analyzing a two-order transmission error curve parabola function, establishing a mathematic model of a two-order transmission error, calculating a rotation angle of the slave wheel, obtaining an imaginary expanded tooth profile equation based on an expanded tooth bar method, calculating the imaginary active wheel expanded tooth profile, calculating the imaginary slave wheel expanded tooth profile having the two-order transmission error, and calculating the shaping equation of the shaping grinding wheel having the two-order transmission error.

The invention relates to a new tyre vertical pressure distribution function, an algorithm and a test system. The new tyre vertical pressure distribution comprises steps that, S1, an average pressure module is determined; S2, inner vertical grounding blotting length is acquired; S3, a bias coefficient is acquired; and S4, the new tyre vertical pressure distribution function is constructed. Through the function and the algorithm, problems of relatively low precision and can-not-be-excellently-reflected tyre rolling direction existing in a traditional tyre vertical pressure distribution function employing a parabola function are solved, in combination with the average pressure module, the inner vertical grounding blotting length and the bias coefficient, the new tyre vertical pressure distribution function capable of realizing simple and accurate computation is constructed, and thereby the vertical pressure distribution situations are conveniently tested.

The invention relates to a two-point parabola interpolation method for improving radar ranging precision, and belongs to the technical field of pulse method radar ranging. The method includes the steps: fitting an echo pulse pressure result of the 3dB beam width into a parabola function y=ax2+bx+c to determine a parameter a by using prior information under the condition that the relationship between the sampling rate and the bandwidth is determined and a window function is selected; then only taking a maximum sampling point and a second maximum sampling point from the echo pulse pressure result, taking the sum of amplitudes of the two sampling points as an estimated peak value, normalizing the amplitudes of the two sampling points by using the estimated peak value, and then performing parabola fitting; according to an abscissa calculation formula corresponding to the maximum value of a parabola function, interpolating and estimating the sampling position where the echo peak value occurs; and finally, considering that an error exists when the echo pulse pressure result is fitted into a parabola function, correcting the parameter a, further improving the accuracy of the estimated peak value position, and reducing the distance quantization error.

The present invention provides a test device and method for obtaining the maximum resolution of an image in a karst cave water environment. A true-color camera and a light supplementing device are disposed on an adjustable bracket; a resolution test card and a transparent sink are arranged on a fixed frame; the true-color camera, the light supplementing device, the transparent sink and the resolution test card are located on the same vertical plane; the position of the light supplementing device is higher than that of the true-color camera; the lens of the true-color camera and the center of the resolution test card are located on the same plane; the transparent sink is disposed between the true-color camera and the resolution test card; the resolution test card is disposed at the outer side of the transparent sink; the transparent sink has an accommodating space for accommodating different dissolution media; a turbidity tester measures the turbidity of a tested solution; a controllerreceives the test values of the turbidity tester and the resolution test card; a quadratic parabola function is adopted to fit data under different light supplementing intensities; and the variation law of a maximum resolution corresponding to the light supplementing intensities can be determined.

The invention discloses a modulating pulse current welding method and system of an aluminum alloy thin plate and a storage medium. The method comprises the following steps that based on the standard formula of the parabolic function, the welding peak current is calculated, and welding parameters are configured; and welding operation is started based on a preset parabola curve according to the welding peak current obtained through calculation and the configured welding parameters. According to the ladder single pulse current welding method achieving modulating through the parabolic function waveform, the effect of a strong and weak pulse group stirring molten bath is formed, and bubble escape is facilitated; and in addition, the ladder waveform has the globular transfer control stage, globular transfer regularity in the welding process is high, welding seam formability is good, the good welding seam forming effect is achieved on welding of the aluminum alloy thin plate, and the method and system can be widely applied to the technical field of metal welding.

The invention discloses a carrier phase high-precision GNSS receiver group delay measurement method and system; the method comprises the steps: enabling a narrowband spread spectrum signal to pass through a to-be-measured group delay characteristic channel, and obtaining a code phase measurement value and a carrier phase measurement value after the narrowband spread spectrum signal is captured and tracked; then, approximating the group delay into a parabolic function by utilizing the characteristic that the group delay in a narrow-band signal passband changes gently, and traversing parabolic parameters and integer ambiguity; and finally, when the difference value between the group delay characteristic obtained by traversing the parabola parameter and the group delay characteristic obtained by traversing the combination of the integer ambiguity and the measured carrier phase is minimum, determining that the group delay characteristic corresponding to the parabola parameter is the actual group delay characteristic of the channel; meanwhile, the group delay measurement of any frequency resolution can be realized by changing the frequency range of the frequency division multiple access signal.

Restrictors are disclosed that include a body defining a Venturi tube having a throat defining a junction of a converging inlet cone to a diverging outlet cone along a longitudinal axis thereof, and with the converging inlet cone and the diverging outlet cone each defining an inner passageway that transitions as a hyperbolic or parabolic function toward the throat.