33 results about "Parabolic function" patented technology

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.

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 present invention provides for bevel gears having a localized and stable bearing contact. The localization of bearing contact is achieved by substitution of flat tooth surfaces with parabolic tooth surfaces. This is accomplished by either modifying line-contact directly or by using a generating parabolic cylinder during generation of the tooth surfaces. The actual contact area is spread over an ellipse centered around an instantaneous theoretical point of contact at the apex of the parabolic tooth surface. This localized bearing contact reduces the shift of the bearing due to assembly and manufacturing errors, thereby providing a more durable and quieter gear. Furthermore, the geometry of the gear enables creation of dies from which the gear may be forged. Transmission errors are modeled using a pre-designed parabolic function that coincides with the parabolic tooth surface design of the present invention.

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.

Devices and methods for hands-on learning of mathematical parabolic concepts are provided. For example, a device for teaching mathematics includes a base having a plurality of channels for accepting vertical rods of varying lengths; a lever movably attached to the base at a pivot, the lever passing through the plurality of channels; and a plurality of vertical rods, each of the plurality of vertical rods located at least partially in one of the plurality of channels and resting on the lever; wherein the plurality of vertical rods are sized and arranged so that the tops of the vertical rods illustrate a parabolic function; and wherein moving the lever about the pivot moves the plurality of rods within the plurality of channels and illustrates changes to the parabolic function represented by the vertical rods.

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.

The present principles relate to a method and device for gamut mapping from a first color gamut towards a second color gamut. The method comprises the steps: in a plane of constant hue, obtaining a target lightness for a color on the boundary of first gamut with maximum chroma, called first cusp color; and lightness mapping of the color from the first color gamut towards the second color gamut wherein the lightness mapped color is calculated from a parabolic function applied to the color, the parabolic function mapping the first cusp color to a color having the target lightness. According to aparticular characteristic, a preserved chroma is also obtained; and in case the chroma of the color is lower than or equal to the preserved chroma, the lightness mapped color is the color, and in case the chroma of the color is higher than the preserved chroma, the lightness mapped color is calculated from the parabolic function applied to the color.

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.

The invention discloses a data display method and aims to solve the problem of poor visual effect caused by small numerical value increase. The method comprises the following steps: building a stereoscopic model; dynamically reading a numerical value added value; determining the height of the stereoscopic model according to the added value; displaying the stereoscopic model according to the height. The invention further discloses a data display device. The bar chart height of a data bar chart is dynamically changed according to the numerical value added value of the input data, and the numerical valve increase frequency is judged, the increase speed of the bar height is dynamically changed, and meanwhile, the color of a bar is changed. A parabola quadratic function is utilized to control the numerical valve increase frequency and change the increase amplitude of the bar, so that the problem of poor visual effect caused by small numerical value increase is solved.

The invention discloses a parabola-based regional tropospheric wet delay calculation method, which includes: 1. Collecting the sounding data, annual cumulative days and spatial position data of each sounding station in the target area, and calculating according to the collected sounding data The true value of the tropospheric wet delay of each sounding station; 2. Establish a parabolic function model of the tropospheric wet delay; 3. The true value of the tropospheric wet delay, annual cumulative day, latitude value, and altitude value of the sounding station obtained in step 1 Substitute into the tropospheric wet delay parabolic function model, determine the coefficients, and obtain the tropospheric wet delayed parabolic function model in the target area; The tropospheric wet delay parabolic function model is used to obtain the calculated value of the tropospheric wet delay of the site to be measured. This method is suitable for locations where radiosonde data cannot be obtained, and considering the influence of seasons, it can obtain more accurate tropospheric humidity delays.

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 proposes a wave direction inversion method for ship-borne coherent microwave radar. This method first estimates the left and right bandwidth boundary frequencies and center frequency of the ocean echo signal from the range Doppler spectrum echoes obtained from multiple irradiation directions of the radar, and then converts the center frequency into velocity and deducts the ship speed component to obtain the water quality. point speed. Then the water particle velocity measured in each direction is converted into a wave number spectrum to synthesize an undirected ocean wave spectrum. Then, the wave value corresponding to the peak is obtained from the undirected wave spectrum by searching for the maximum value, and the wave number energy of the peak in each direction is arranged symmetrically in a circular distribution, and then the fuzzy wave direction is obtained by constructing a parabolic function model. Then, the variance of the left and right bandwidth boundary frequencies corresponding to the maximum irradiation direction of the spectral peak wave number energy is used to eliminate the 180° ambiguity. Finally, combined with the heading of the ship, the wave direction with true north as the reference is obtained. The invention enables the ship-borne coherent microwave radar to have the capability of navigating and monitoring the direction of sea waves.

The invention discloses a method for generating an arbitrary-angle cone light beam with distinguishing characteristics, which comprises the following steps: S1, constructing a parabola with the height h and the width w, putting the parabola in a rectangular coordinate system, and obtaining a parabola function expression when the origin of a coordinate axis is at the vertex of the parabola; s2, rotating the parabola around the symmetry axis of the parabola by 180 degrees to obtain a paraboloid with a reflection characteristic; s3, a light emitting source is arranged at the focus of the paraboloid, light emitted by the light emitting source is reflected by the paraboloid to obtain a conical light column with the angle beta, namely, the conical light column with any angle beta is obtained, and a bottom aperture of the conical light column has the distinguishing characteristic that the inner ring is bright and the outer ring is dark; the light sensing device can conveniently identify the light source and eliminate interference of other light sources; the device can generate a conical light beam with any angle, is suitable for different landing site environments, can prevent the visual detection distance of a system to an effective light source from being reduced, and reduces the later computer visual processing difficulty.

The invention discloses a method for forecasting the service life of a lead-acid storage battery. The method comprises the steps of: periodically activating the storage battery to obtain an activated charging capacity thereof and thereby obtain a variable point (t, Sc) of each periodically activating time t and the corresponding charging capacity Sc; naturalizing the variable point (t, Sc) obtained after each activation to the corresponding normal capacity point (ti, Sci), wherein i is the number of corresponding periodically activating times; calling a least square method to fit a parabolic function Sc=(i)at( / i)2(i)+bt( / i)+c of the charging capacity Sc and the time t as the forecasting curve for the service life of the storage battery, wherein a, b and c are related coefficients of the parabola. The method for forecasting the service life of the lead-acid storage battery achieves improved forecasting accuracy, and is applicable to various storage batteries and low in forecasting cost; the forecasting method adopts a single parameter for forecasting, thus reducing computation complexity.

The invention discloses a phosphorus pig iron cast negative electrode assembled carbon block. According to an aluminum electrolysis theory and a current distribution demand, two sections of steel sticks and a through long steel stick are selected; negative electrode carbon blocks of the two sections of steel sticks and the through long steel stick are opposite to centre joints of two positive electrodes; a non-conductive material is used for filling; the non-conductive material is used for filling the parts outside the positive projections of the positive electrodes; at a manual leg extension position, advanced shaping is adopted; and the shape is set according to a parabolic function y=x<2>. According to the phosphorus pig iron cast negative electrode assembled carbon block, the current density of the negative electrode is improved by 5 to 7 percent, and the problem that the heat capacity of the phosphorus pig iron cast negative electrode tank is insufficient is solved; the conductivity of the manual extended leg position is gradually reduced from inside to outside, so that an effective furnace upper is formed; and therefore, manual extended leg is protected; and dual purposes of obtaining high energy saving and consumption reduction indexes and prolonging the service life of an aluminum electrolytic cell are realized.

The present invention relates to a new tire vertical pressure distribution function, algorithm and testing system. The tire vertical pressure distribution algorithm includes the following steps: step S1, determine the average pressure module; step S2, obtain the longitudinal length of the ground contact footprint; step S3, obtaining the bias coefficient; and step S4, constructing the tire vertical pressure distribution function; the present invention solves the technical problem that the traditional tire vertical pressure distribution function uses a parabolic function, which causes low precision and cannot well reflect the tire rolling direction ; and combined with the average pressure module, the longitudinal length of the contact patch and the bias coefficient, a simple and accurate tire vertical pressure distribution function is constructed, which is convenient for testing the tire vertical pressure distribution.