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414 results about "Superposition principle" patented technology

The superposition principle, also known as superposition property, states that, for all linear systems, the net response caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually. So that if input A produces response X and input B produces response Y then input (A + B) produces response (X + Y). A function F(x) that satisfies the superposition principle is called a linear function.

Method for caculating displacement of nearby existing subway tunnel due to foundation pit excavation

The invention provides a method for caculating displacement of a nearby existing subway tunnel due to foundation pit excavation. The method specifically comprises the following steps of establishing a calculation model first, performing unloading analysis on the pit bottom, then performing unloading analysis on the side walls of a foundation pit, and finally, obtaining the horizontal total displacement Sx and the vertical total displacement Sz, which are caused by unloading stress generated by the pit bottom and surrounding side walls of the foundation pit, of a certain point (x1, y1, z1) on the outer side of the tunnel by utilizing a superposition principle; in order to accurately calculate the outside displacement of the tunnel under the action of loads of the pit bottom and surrounding side walls of the foundation pit, the half-side tunnel towards the foundation pit is uniformly divided into a plurality of points, displacement values of the plurality of points are respectively calculated, and finally, an average displacement value is used as the displacement value of the tunnel.Therefore, the construction of a specific project can be simulated by using the method before construction so as to calculate the displacement of the subway tunnel in specified working conditions, and if the displacement of the tunnel exceeds a corresponding allowable value, related construction parameters can be adjusted for trial computation till reaching safety standards.
Owner:ZHEJIANG UNIV CITY COLLEGE

Blasting vibration predicting method

The invention provides a blasting vibration predicting method, which comprises the following steps of: firstly, determining a reference blasting hole and a plurality of vibration measuring points, and placing vibration meters on each vibration measuring point; blasting the reference blasting hole to obtain blasting vibration waveforms having different distance points; and finally, executing a blasting vibration waveform predicting process. In the prediction process, actual blasting vibration test data is obtained firstly, the blasting vibration waveforms and migration stacked delay time of each blast hole on a predicting target point are then calculated according to distance from the predicting target point to the each blast hole and the reference blasting hole, and the vibration waveform of the predicting target point can be obtained based on a vibration wave stacking principle. A blasting vibration predicting result which is obtained by adoption of the method really shows an influence of a topographic condition of a field on blasting vibration, and the integral vibration waveform of the predicting target point can be obtained; a predicted vibration velocity peak value of waveform particles is quite approximate to an actually-measured vibration velocity peak value, and a time difference between the predicted vibration velocity peak value and the actually-measured vibration velocity peak value is also quite small; and an analysis result is accurate and reliable, so that adjustment of a blasting scheme can be better guided.
Owner:RAILWAY ENG RES INST CHINA ACADEMY OF RAILWAY SCI +1

Novel practical method frangibility index method for evaluating seam floor water inrush

InactiveCN101699451ASolve the difficult problem of water inrush prediction and evaluationSpecial data processing applicationsMaterial defectCoupling
The invention relates to a frangibility index method for evaluating seam floor water inrush, which comprises the following steps: determining main control factors of the seam floor water inrush by taking GIS as an operating platform based on a multi-source information fusion theory, and establishing a sub-subject layer diagram for each main control factor through data acquisition, analysis and processing; determining the 'contribution' or the 'weight' of each main control factor to a complex water inrush process and establishing a forecast evaluation model for the seam floor water inrush through the inversion identification or the learning training of the model by applying a multi-source geoscience data composite superposition principle and adopting a modern linear or non-linear mathematical method; and reasonably determining a subarea threshold value of the water inrush frangibility according to the analysis of a frequency histogram of water inrush frangibility indexes calculated by each unit in a research area and finally making a scientific division and a forecast evaluation on the seam floor water inrush frangibility. The method well overcomes the difficulty of the forecast evaluation on the seam floor water inrush, breaks through the restriction by significant deficiencies that the conventional water inrush coefficient method for the seam floor water inrush evaluation can only consider two control factors and has no influence 'weight' concept and the like, and adopts the GIS and the modern non-linear mathematical coupling method to truly depict the non-linear dynamic process of the seam floor water inrush which is controlled by a plurality of factors and has a very complicated formation mechanism.
Owner:CHINA UNIV OF MINING & TECH (BEIJING)

Method for measuring three-dimensional power-frequency electric field on basis of curve integral of equivalent charges on surfaces of transmission conductors

A method for measuring a three-dimensional power-frequency electric field on basis of curve integral of equivalent charges on surfaces of transmission conductors includes acquiring relevant parameters of intensity of the three-dimensional power-frequency electric field of a transmission line at first; then building a three-dimensional model for the transmission line hung at different altitudes on the basis of a conductor catenary equation; determining the actual height of the corresponding conductor located at an optional position of the transmission line within a span; further obtaining the equivalent charges on the surface of the corresponding conductor located at the optional position of the transmission line within the span by a curve integral method for the equivalent charges on the surfaces of the conductors of the transmission line hung at the different altitudes; and finally, computing the intensity distribution condition of a space electric field generated by a multi-conductor system according to a field intensity superposition principle when the conductors at two ends of the span have different altitudes. By the aid of the method, an actual spatial erection condition of the high-voltage power line can be truly reflected, and the method is favorable for accurately computing the intensity of the three-dimensional space electric field of the high-voltage transmission line, and provides a reliable basis for evaluating an electromagnetic environment of the transmission line.
Owner:STATE GRID SICHUAN ELECTRIC POWER CORP ELECTRIC POWER RES INST +1

Load forecasting method of power distribution network with distributed power supply

ActiveCN103514487AComprehensive understanding of load characteristicsSolve the problem of difficult prediction of output characteristicsForecastingLoad forecastingDistributed power
The invention provides a load forecasting method of a power distribution network with a distributed power supply. The distributed power supply comprises a wind generator set and a photovoltaic power generation system. The load forecasting method of the power distribution network includes the following steps that load forecasting information is collected; a load year characteristic curve of a planning region is forecasted, a year power output characteristic curve of the distributed power supply is forecasted; a year load characteristic curve of the power distribution network with the distributed power supply is forecasted. According to the load forecasting method, random characteristics of power output of the distributed power supply are considered, a year power output curve of the distributed power supply is simulated through Monte Carlo simulation, a total load characteristic curve of the power distribution network is obtained on the basis of different load forecasting, and finally a net load year characteristic curve of the power distribution network is obtained by synthesizing total load characteristics and distributed power supply power output characteristics and based on the time characteristic stacking principle. Thus, the load forecasting problem of the power distribution network with the distributed power supply can be well solved.
Owner:STATE GRID CORP OF CHINA +2

Fault-tolerant-vector-control-based third harmonic current injection method of five-phase permanent-magnet motor

The invention discloses a fault-tolerant-vector-control-based third harmonic current injection method of a five-phase permanent-magnet motor. The method comprises: a fundamental wave decoupling model under various open-circuit faults of a five-phase permanent-magnet motor is established and a corresponding fundamental fault-tolerant current is deduced; according to a magnetic resonance method, a torque mathematical model under the fundamental fault-tolerant current is established; on the basis of the established torque model, an expression of third harmonic current injection under various open-circuit faults is deduced; on the basis of a superposition principle, the fundamental current is added to the third harmonic current to obtain a total fault-tolerant current; and with corresponding deflation clark and park transform, a current component under a rotation orthogonal coordinate system is obtained, so that third harmonic current injection under magnetic field orientation control and fault-tolerant vector control under faults is realized. Therefore, on-line calculation of the third harmonic current under fault-tolerant vector control and injection of the third harmonic current at a fixed switching frequency are realized; the torque ripple is suppressed and the system robustness is enhanced; and the switching loss and the electromagnetic interference are reduced.
Owner:JIANGSU UNIV

Array antenna pattern time domain measurement method

An array antenna pattern time domain measurement method belongs to the technical field of antennas, and comprises the following steps: measuring the patterns of array antenna units firstly, irradiating the array units from different angles (theta and Phi) by uniform plane waves, measuring the transient state responses of the array units under the irradiation of the plane waves by a digital oscilloscope, normalizing the transient state responses to obtain patterns of the array units under the conditions of uniform amplitude and cophase excitation, and synthesizing the array pattern through adopting a digital signal processing technology and a superposition principle of the patterns of the array antenna unit finally. The array antenna pattern time domain measurement method has the advantages that (1) the array pattern is beneficial for the precise synthesis under the array circumstance; (2) the patterns of the array units under the random given excitation can be measured; and (3) the array scanning grain pattern can be synthesized so as to be more beneficial for obtaining the maximum gain distribution area and the scanning blind point distribution area. The array antenna pattern time domain measurement method has the characteristics of simplicity in operation and high testing efficiency, and reduces the site requirement and the testing cost at the same time.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Segmentation multi-cluster fractured horizontal well yield prediction method for shale gas reservoir

InactiveCN107622328AImprove forecast accuracyAccurately reflect the actual seepageForecastingFluid removalPhysical modelOperability
The invention belongs to the technical field of shale gas development, and particularly relates to a segmentation multi-cluster fractured horizontal well yield prediction method for a shale gas reservoir. The method comprises the following steps that: establishing a physical model; obtaining an apparent permeability rate calculation method; according to the permeability rule and the pressure superposition principle of gas in a stratum, obtaining the overall pressure drop and crack grid traffic relational expression of all crack grid traffics for any point in a gas reservoir; according to the flowing relationship of gas in a crack and a boundary coupling relationship between the crack and the strum, obtaining a gas reservoir-crack coupling flowing equation; and adopting a matrix analysis method and a numerical iteration algorithm to obtain the horizontal well yield. By use of the method which is put forward by the invention, a blank of a segmentation multi-cluster fractured horizontal well yield prediction model which considers the complex and multiple migration mechanism is filled. The method has the characteristics of being convenient in calculation, high in operability, effectiveand practical, and a basis can be provided for optimizing the horizontal well segmentation multi-cluster fractured parameters of the shale gas.
Owner:SOUTHWEST PETROLEUM UNIV

Rapid and accurate computation method for large-scale MIMO array antenna far-field radiation field

The present invention belongs to the field of electromagnetic value computing, and particularly relates to a rapid and accurate analysis method for large-scale MIMO array antenna far-field radiation. The method comprises: determining a structural parameter of an M*N-element plane array antenna; computing a relationship between an incident field and a scattered field of an element antenna; according to mutual coupling characteristics among element antennas, selecting a sub-array form and size of an extraction unit on an array environment condition; for an antenna sub-array of the extraction unit, computing a unit far-field radiation pattern of the sub-array; and according to the unit far-field radiation patterns of the array and a superposition principle, computing an array antenna far-field radiation pattern. According to the invention, by utilizing the accuracy of mutual coupling computation, the problems that the use of such methods as the moment method, the finite element method and the finite difference time domain (FDTD) method are limited by computing capacity of a single computer, and when the scale of the array antenna is too large, rapid and accurate computation of the antenna radiation field cannot be implemented with a full wave simulation method because of large consumption of memory and computing time, are effectively solved. The method provided by the invention is capable of analyzing the radiation pattern of a large and conformal array antenna, and has higher synthesizing accuracy and higher analysis speed.
Owner:THE PLA INFORMATION ENG UNIV

Closed mast strength measurement method and special measurement device

The invention provides a closed mast strength measurement method and a special measurement device. Stress and displacement response of the mast are measured by using a sucking disc spring scale loading device; response of the mast is measured by using a sensor bracket loading device; test values loaded on sides of the mast are accumulated in accordance with linear superposition principle in order to result in the test value under the action of all the loads, therefore, a mast model test is realized. On the basis of linear superposition principle, the invention, aiming at force-bearing features of the closed mast in the wind, provides a method in which the sides are loaded respectively to implement the model test. The invention, according to the feature that tension and pressure are jointly applied on the mast in the wind, provides the sucking disc spring scale loading system and the sensor bracket loading system to simulate the wind force that is applied to the mast; such two systems can realize surface tension loading and surface pressure loading of a complex structure. The invention solves the difficulty that non-wind tunnel test of mast scaled model test cannot be implemented, and offers an ideal alternative proposal for the design and the test of the closed mast.
Owner:HARBIN ENG UNIV

Raman spectrum superposition-based method for quickly determining content of methanol in methanol gasoline

The invention discloses a Raman spectrum superposition-based method for quickly determining the content of methanol in methanol gasoline. The Raman spectrum superposition-based method comprises the following steps of: firstly, measuring a base oil spectrum, a pure methanol spectrum and a methanol gasoline spectrum with known methanol content; secondly, obtaining a spectrum superposing formula according to data and storing base oil and a corresponding spectrum superposition parameter in a spectrum database; and constructing the spectrum database and then estimating the content of the methanol from the methanol gasoline spectrum with the unknown methanol content by using the spectrum superposition formula. The invention provides the spectrum superposition formula from a view of spectrum soft processing as well as the formula-based method for quickly determining the content of the methanol in the methanol gasoline. According to the method, the quantity of samples required to be calibrated can be greatly reduced in the application process, the labor capacity of calibrating works is reduced and the problem that the measurement for low-content methanol is inaccurate or even cannot be measured in the traditional method is overcome; and in addition, the measurement precision of the unknown methanol gasoline prepared from the base oil can also be maintained.
Owner:ZHEJIANG UNIV

System and method for testing lens parameters based on Hartmann-Shark sensor

The invention relates to a system and a method for testing lens parameters based on a Hartmann-Shark sensor. The method comprises the following steps of: by injecting a reference beam to a tested lens, detecting a light wave front which is emitted from a tested lens by using a wave-front sensor; reconstructing the light wave front; calculating a convergence/radiation center of the light wave front, thereby obtaining the positions of the focus length, a focal point and a principal plane of a positive/negative lens; obtaining the positions of the focus length, the focal point and the principal plane in different wavelengths by using different wavelengths of incident lights enter the tested lens; carrying out wave front analysis on the reconstructed and reduced wave front; according to a wave front superposition principle, expanding the tested wave front into a superposition mode of an aberration element by using a least square method, wherein each aberration element corresponds to a weight factor in a certain size; and obtaining lens aberration distribution condition by discussing the distribution of the weight factors. The invention can completely inspect focus length parameters and aberration quality of the lens, is combined with an adjustable-wavelength laser, can measure chromatic aberration and inspects the change condition of the lens focus length and the aberration distribution under different wavelength conditions.
Owner:UNIV OF SHANGHAI FOR SCI & TECH

Modeling and control method for color register system in electronic shaft gravure printing machine acceleration process

The invention relates to a modeling method for a color register system in the electronic shaft gravure printing machine acceleration process. The modeling method comprises the following steps that (1) error open-loop data of the color register system in the electronic shaft gravure printing machine acceleration process are collected; (2) filtering processing is carried out on the collected error open-loop data, so that a mathematical model of the color register system in the electronic shaft gravure printing machine constant-speed process is obtained; (3) the error open-loop data generated by the color register system of an electronic shaft gravure printing machine in the acceleration process are regarded as knowable disturbance, the mathematical model of the color register system in the electronic shaft gravure printing machine constant-speed process is corrected according to the principle of linear superposition, and therefore a dynamic model of the color register system in the electronic shaft gravure printing machine acceleration process is obtained. According to the modeling method for the color register system in the electronic shaft gravure printing machine acceleration process, obtaining of good control performance serves as the purpose, and the obtained model can eliminate inconsistency of all units in an actual system.
Owner:HUAZHONG UNIV OF SCI & TECH

Voltage dip source positioning method based on disturbance power direction

The invention provides a voltage dip source positioning method based on the disturbance power direction and belongs to automatic monitoring methods for power grid voltage dip source positioning. The method is characterized in that under the effect that a disturbance voltage in a power grid fault process is obtained according to the superposition principle of linear circuits, the direction of an active disturbance power flow is used for accurately positioning a voltage dip source; when active disturbance power is positive, a disturbance source is located at the upstream portion of a monitoring point; when the active disturbance power is negative, the disturbance source is located at the downstream portion of the monitoring point; an algorithm of the corresponding disturbance power is given. The voltage dip source positioning method can be used for certainly positioning voltage dips caused by various power grid faults, is suitable for radiation type or ring type or single-circuit type or two-circuit type or single-power-supply type or multi-power-supply type grid structure power grids, and is also suitable for voltage dip source positioning caused by capacitor switching, transformer switching and large motor starting disturbance; according to the voltage dip source positioning method, the voltage and current of the monitoring point need to be sampled synchronously.
Owner:CHINA UNIV OF MINING & TECH +2

Thermal expansion error modeling and compensating method for semi-closed-loop feed shaft under excitation of multi-time-varying dynamic heat source

The invention provides a thermal expansion error modeling and compensating method for a semi-closed-loop feed shaft under the excitation of a multi-time-varying dynamic heat source and belongs to the field of numerical control machine tool error compensation. The generation mechanism of heat by friction, the heat conduction mechanism and the heat convection mechanism, under the excitation of a multi-temporal and variation-dynamic heat source, are analyzed. According to the superposition principle of the temperature field, a temperature field prediction model under the excitation of a nut pair time-varying dynamic heat source and a temperature field prediction model under the excitation of a bearing seat time-varying dynamic heat source are respectively established. Through integrating a discrete screw temperature field at any time, the predicted value of the real-time thermal expansion error of a screw can be obtained. The predicted value of the thermal expansion error of the screw is written into a numerical control system in real time, and then the thermal error of a feed shaft can be compensated. The above model records the dynamic change process of the discrete temperature field of the feed shaft, namely the change of the motion state of the feed shaft. Meanwhile, the good compensation effect is still realized. The above method is high in prediction accuracy, and is strong in robustness for the change of the motion state.
Owner:DALIAN UNIV OF TECH
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