43 results about "Boundary equation" patented technology

The invention relates to a log multi-parameter oil-gas layer interpretation and evaluation method based on a radar map and a cloud model. The method comprises the steps of: obtaining interpretation and evaluation parameters by normal geological log, gas log, geochemical log, nuclear magnetic log and the like; integrating log interpretation databases; drawing the log multi-parameter oil-gas interpretation radar map according to different reservoir types in different areas by using the databases; and mapping the interpretation parameters onto the rays of the radar map. The radar map is divided into a good reservoir, a medium reservoir and a poor reservoir from inside to outside; the area of the radar map is taken as the characteristic quantity for finishing characteristic extraction; the area of the radar map is used to calculate a cloud boundary equation, and the cloud boundary equation is mapped on the manufactured cloud scale; the cloud model is the same as the radar map, namely the reservoir is divided into a dry layer area, a low-yield oil-gas layer area and an oil-gas layer area with industrial value from inside to outside. The intuitional and quantitative interpretation and evaluation of log multi-parameter oil-gas reservoirs is realized by the radar map and the cloud model. The interpretation coincidence rate can be increased, and the interpretation conclusion is represented by a graph, so that the log multi-parameter oil-gas layer interpretation and evaluation method is intuitional in expression and strong in applicability.

The invention relates to an anisotropic reverse time migration method for a quasi-P wave equation in a transverse isotropy with a vertical axis of symmetry (VTI) medium. The method comprises the following steps of: (1) performing discrete differentiation on a first-order quasi-P wave equation in a two-dimensional VTI medium and a perfect matched layer (PML) absorption layer boundary equation by adopting staggered meshes to obtain high-order difference formats of forward continuation and reverse continuation of the two equations; (2) performing numeric calculation to obtain a forwards-continued wave field of a shot point and a reverse time continued wave field of a receiver point, and performing normalized correlation operation on the two wave fields to obtain a migration imaging result of each imaging point in a model; and (3) extracting common imaging point gathers from migration results to obtain a final migration profile. By the method, a problem about the migration imaging of intensive transverse speed variation and a high dip angle stratum can be solved; and the influence of anisotropy of the medium is also taken into account, and the good imaging effect of longitudinal wave data acquired from an anisotropic region can be achieved by an anisotropy-theory-based migration method.

The invention discloses an agricultural drought remote sensing monitoring method, which comprises the following steps: 1) calculating enhanced vegetation index and land surface temperature according to surface reflectance and thermal infrared remote sensing images; 2) constructing an ETVDI model through the surface temperature and the enhanced vegetation index calculation result, and obtaining maximum value and minimum value of the surface temperature under the same enhanced vegetation index value and the number of pixel points at the points of same surface temperature values corresponding to different enhanced vegetation index values; and 3) carrying out polynomial fitting on the maximum value and minimum value corresponding to the same enhanced vegetation index value to obtain wet and dry boundary equations in the ETVDI model, and obtaining fitting parameters. The method overcomes the defect that a conventional TVDI model has vegetation index saturation easily in a dense vegetation area and the defect of uncertainty of wet and dry boundary equation fitting, thereby improving fitting precision; precision is higher in the expression aspect of temporal and spatial development of the drought; and the method can reflect the process of drought growing, development and elimination more truly, and provides reference for early warning and monitoring of the agricultural drought.

The invention discloses a colorimetry color feature vector automatic extracting method based on machine vision, which can greatly reduce system construction cost while realizing a broad spectrum water quality test. In the technical scheme, the colorimetry color feature vector automatic extracting method based on the machine vision is characterized by comprising the following steps of: 1, shootinga digital image for a sample pate of a water quality detection test, and determining four relevant positioning points on the image; 2, establishing four vector straight line equations on the basis ofthe positioning points in the step 1; converting the four vector straight line equations into four boundary equations of searching regions based on pixels; converting the images in the searching regions into binary images; carrying out region marking on the binary images to obtain K positions of regions of interest in the binary images; and acquiring the K regions of interest on the initial digital image, i.e. calculating M relevant feature vectors in each region.

The invention discloses a method for eliminating error of cylinder screw thread non-contact measurement. The method comprises the following steps: presenting a concept of projection boundary, establishing projection boundary equation, obtaining difference relation of screw thread intersection line and projection boundary and correcting cylinder screw thread parameter. By employing the above method, spatial position relation is formed according to the screw thread projection boundary, the projection boundary equation is creatively established, the difference relation of the screw thread intersection line and the projection boundary is deduced on the former base, and extracted coordinates of points on cylinder screw thread image shot by a CCD camera are repeatedly corrected until the obtaining of cylinder screw thread parameter which satisfies precision requirement. The method is concise, visual, easy to grasp and easy to realize automatic detection. The non-contact detection method can avoid measurement error of high precision cylinder screw thread, and eradicate screw thread product quality problem caused by screw thread non-contact detection error.

The invention discloses a power distribution system network reconstruction method based on a safety domain. The power distribution system network reconstruction method comprises the following steps: according to a power distribution system safety domain, a safety boundary equation, constructing a safety index of the power distribution system safety domain; according to the safety index of the power distribution system safety domain, combining a genetic algorithm so as to acquire a network reconstruction model; carrying out reconstruction on a power distribution system network through the network reconstruction model so as to acquire a final switch state of the whole network. In the method, the improved genetic algorithm is used to solve the network reconstruction model so that individual ''precocity'' can be avoided; a convergence effect is good and the algorithm is stable. By using the method, a new thought is provided for application of a power distribution network safety domain theory; a good guidance effect on optimization operation of a N-1 demanding large-scale connected city power distribution network is realized.

The invention discloses a method for calculating a time-varying bending moment and bending deformation of a bridge under the action of a moving vehicle load, and belongs to methods for calculating bending moments and deflection of bridges. The method comprises the steps of (1) listing out a bending moment equation of the bridge under the action of the moving vehicle load based on a singularity generalized function; (2) substituting a bending moment into a deflection curve differential equation, and performing integration on the differential equation twice based on a singularity generalized function integration method to obtain a deflection curve equation; (3) complementing equations according to constraint conditions to solve unknown variables in the deflection curve equation, namely, listing out a deflection equation of the bridge at a support and a force boundary equation of a rightmost support; (4) solving the complementary equations by virtue of Mathcad to obtain constraint reactions and integral constants changed with vehicle load speeds and time; (5) substituting the obtained constraint reactions and integral constants in the Mathcad into the bending moment equation and the deflection curve equation to obtain corresponding bending moment function and deflection function; and (6) enabling the method to be suitable for deformation calculation of the bridge under the condition of different spans, different vehicle load quantities, different vehicle load moving speeds and different vehicle moving directions.

The invention discloses a transient traveling wave time domain calculating method of a same-tower double-circuit DC power transmission line. The method includes the following steps of calculating the series impedance matrix Z and the parallel impedance matrix Y of the line at different frequencies, the eigenvector matrixes TU, TI of the matrixes ZY and YZ, and an eigenvalue matrix Lambda; calculating the vector wave impedance matrix Zc-phase and the sequential wave impedance matrix Zc-phase-r according to the matrixes Y, TI, and Lambda; performing vector fitting on the matrixes TU, TI, TU-1, and TI-1 to obtain TU-r, TI-r, TU-r-1, and TI-r-1; performing vector fitting on the propagation coefficients exp (-gamma Mm) of the forward wave of different moduli to obtain a sequential propagation coefficient matrix Hm-r of the corresponding m mold; determining the fault type according to the circuit structure of the fault points to write the boundary equation; and calculating the line fault transient electrical amount. The method takes into account the influence of the frequency variation of the line parameters, and solves the problem of the line decoupling caused by the unbalanced same-tower double-circuit DC line.

The invention discloses a rapid construction method of a thermally stabilized safety domain based on an injection power space of a key node. The method comprises that a state variable is set; a control variable is determined; and the thermally stabilized safety domain is constructed. A concept of key node is provided, the thermally stabilized safety domain defined in the injection power space is changed into a simplified safety domain described by a key node space by dimension reduction; and on the basis of a hyperplane characteristic of a boundary of the safety domain, a rapid calculation method of the safety domain coefficient is provided according to a trend constraint boundary equation of a line. Thus, the construction method of the thermally stabilized safety domain can be used to overcome disadvantages that a traditional simulated fitting method includes long calculation time and is not suitable for online application, and the method has better online real-time monitoring, defense and control effects in a large power system. The method can be used to obtain safety margin information and real-time control measures of the system in a present operation point, operation and scheduling of the power grid is guided, and the practical value is high.

The invention provides a matched setting method of minimum excitation limiting and loss-of-field protection based on power plane. The method comprises the steps of calculating a pure power static stable boundary equation of a power generator on a power plane, calculating the static stable boundary according to a system least operation mode of the pure power static stable boundary equation, obtaining loss-of-field protection and minimum excitation limiting which are set according to the static stable boundary, then adjusting the matching coefficient between a minimum excitation limiting wire and the static stable boundary using the phase entering thickness of the power generator as a restraining condition, thereby ensuring matching between minimum excitation limiting and loss-of-field protection which is set according to static stability. The matched setting method has advantages of settling a technical problem of mismatching between minimum excitation limiting and loss-of-field protection of the power generator, improving coordinate matching capability between the power generator and a power grid, and improving stable operation level of an electric power system.

The invention discloses a method for constructing the safety domain model of a flexible power distribution network. The method comprises the following steps of 1) acquiring a full-network feeder linesegment capacity constraint, a main variable capacity constraint and a port adjustment amount constraint of a flexible switching station under the N-0 safety constraint of the flexible power distribution network; 2) acquiring a full-network feeder line segment capacity constraint, a main variable capacity constraint and a port adjustment amount constraint of the flexible switching station under the N-1 safety constraint of the flexible power distribution network; 3) according to the step 1) and the step 2), acquiring a safety domain model, and acquiring an equal sign of the effective constraint in the safety domain model, namely obtaining an effective safety boundary equation of the flexible power distribution network. According to the invention, based on the above steps, the safety domainmodel of the flexible power distribution network is given. Compared with a traditional power distribution network, a technical guidance is provided for the construction and development of the flexible power distribution network.

The invention discloses a low-field nuclear magnetic resonance nondestructive detection line applicable to dried shelled fruits. In the prior art, a method for detecting mildew and insect attack of the dried shelled fruits is achieved by generally removing sample peels for discriminating after random sampling, and no nondestructive detection scheme exists. The low-field nuclear magnetic resonancenondestructive detection line integrates low-field nuclear magnetic resonance equipment and a dried shelled fruit conveying device, so that batch nondestructive detection of the dried shelled fruits sent for detection can be achieved. Principal component analysis is performed on existing sample data, a scatter diagram is drawn, and good and bad seed area division and boundary equation calculationare performed to obtain a suitable mathematical model, so that the analysis rate of the production line sample data is increased. In the detection process, the transverse magnetization intensity signal amount of the dried shelled fruits is detected according to a low-field nuclear magnetic resonance technology, and then through comparison with the constructed mathematical model, the quality conditions of good seeds, mildewy seeds, and wormy seeds of the dried shelled fruits are quickly obtained, so that the accuracy can reach 85% or above.

The invention discloses a quick determination method for security boundary quantity of a power distribution network. The quick determination method comprises the following steps of selecting observation feeder lines, and judging a contact relation thereof; finding an extra element of each loop of observation feeder line; and determining the boundary quantity by selecting a corresponding inclined / linear boundary quantity calculation formula according to the contact relation of the feeder lines. By further researching of the generation mechanisms of the security boundary of the power distribution network, the security boundary quantity determination method according to the contact relation of the feeder lines in the power distribution network is provided; the method does not need security domain simulation or listing writing of a security boundary equation; and instead, the security boundary quantity can be quickly determined by observing the network structure of the power distribution network and by combination with the boundary quantity calculation formula.

The invention discloses a method for constructing an information-driven grid static stability domain boundary. The method comprises the steps that a grid static voltage stability domain boundary equation is constructed; and a parameter tracking method is used to perform prediction correction solving on the boundary equation to acquire a solution set from any boundary point to the entire stabilitydomain boundary and complete the construction of the grid static stability domain boundary. The problem of inaccurate constructing of the grid static stability domain boundary is solved.

There are many 10 kV lines and the terminal low voltage problem is common. Based on the head-end load safety region, the safety margin of terminal voltage can be mastered according to the head-end load during operation, and it is convenient for line selection and reactive power configuration during planning. A fast estimiation method of that boundary of safety region of head-end load of 10 kV transmission line features that the actual load distribution in the platform area is equivalent to the form of balance distribution along the transmission line plus several heavy load points based on theinfluence analysis of the load distribution characteristics in the platform area on the voltage drop of the transmission line. According to the maximum safe voltage drop of the transmission line, thelinear boundary equations of the load safety region at the head end of the transmission line are derived for various equivalent forms of load distribution. The numerical results show that the terminalvoltage is lower than the safety lower limit value if the head-end load is outside the safety region. Conversely, the terminal voltage is at a safe level. An example is given to illustrate the feasibility of the proposed method. The invention can be widely applied to the safe operation and planning of a 10kV distribution network, and has important engineering application value.

The invention discloses a mixed absorbing boundary condition method based on Higdon cosine type weighting, which belongs to the field of forward simulation modeling of seismic exploration, and comprises the following steps of: carrying out a finite-difference numerical simulation by adopting an acoustic wave equation of two-dimensional scalar to divide the whole study area into a central wave field area, a transition area and a boundary area; solving a two-way wave equation of acoustic wave of two-dimensional scalar to obtain a two-way wave field in the central wave field area and the transition area; solving a second-order Higdon absorbing boundary equation to obtain a one-way wave field in the transition area and the boundary area; and performing cosine-type weighted overlay on the two-way wave field and the one-way wave field in the transition area to obtain a final wave field. The mixed absorbing boundary condition method based on Higdon cosine-type weighting adopts a cosine-type weighted overlay mode to construct a mixed absorbing boundary, so that the inner boundary is better coupled with the central wave field area, thereby effectively suppressing the inner boundary reflection of the mixed absorbing boundary.

The invention discloses a numerical value simulation method and system of an elastic wave field. The method can comprise the steps of 1, building a speed model, determining sampling intervals of spaceand time, and performing finite differential mesh discretization; 2, calculating internal wave field data according to an elastic fluctuation equation; 3, calculating angle point wave field data according to an angle point wave field numerical value calculation formula; 4, calculating boundary wave field data according to a wave field absorption boundary equation and a wave field absorption coefficient; 5, acquiring wave field data of the speed model, judging whether a reflection condition of the wave field boundary conforms to a preset standard or not, if yes, executing the step 6, if not, determining a wave field absorption coefficient again, and repeating steps 4 and 5; and 6, outputting final wave field data. The propagation authenticity of an elastic wave in a two-dimensional isotropic medium can be accurately reflected by a model wave field value, and the purpose of improving elastic wave numerical value simulation result accuracy is improved.

The invention discloses a security domain-based traffic network security evaluation method. The traffic network security evaluation method is based on an N-1 security domain. The security domain-based traffic network security evaluation method includes the following steps that: a traffic network security domain under N-1 constraints is calculated, and a traffic network security domain boundary equation set is obtained through the traffic network security domain; after a certain road section is congested, the security boundary distances of the other road sections are calculated; and security evaluation is performed on a traffic network according to the security boundary distances, and a security evaluation result is visualized. With the security domain-based traffic network security evaluation method of the invention adopted, only a topological structure, flow and vehicle speed are required so as to describe the stability of an urban road network; the plus or minus of the security boundary distances describe whether the road network can operate stably when road sections are congested, so that whether a work point is secure or not can be judged; and the numerical values of the security boundary distances can quantitatively represent the stability of the road network.

The embodiment of the invention provides a building method and device for a homopolar crossing fault model between DC systems, and relates to the field of a power system. By the building method and device, an equivalent model of the homopolar crossing earth-free fault between the DC systems can be built. The building method comprises the steps of acquiring a homopolar crossing earth-free fault model by a David equivalent value; simulating the earth-free fault model to obtain a first network topological map and a second network topological map; building a first boundary equation set and a second boundary equation set according to the first network topological map, the second network topological map and a preset rule; acquiring trigger angle values of conversion stations in the first networktopological map and the second network topological map according to a simulation result of the earth-free fault model; building a homopolar crossing earth-free fault equivalent model; and calculatinga fault equivalent impedance value of the homopolar crossing earth-free fault equivalent model according to the trigger angle values of the conversion stations in the first network topological map and the second network topological map, the first boundary equation set, the second boundary equation set and an equation set between a preset rectification side and an inversion side.

The invention discloses a rank-judgment-based method for identifying the feasible region boundary of SCUC model power flow constraints. Boundary; obtain all feasible domain vertices and their corresponding equation boundary sets; count the feasible domain vertex sets corresponding to each equality boundary; judge whether each equation is a boundary constraint according to the vertices, and obtain all equation form boundary constraints; The boundary equality constraints are restored to a set of boundary inequality constraints in the feasible region; the method of the invention can effectively reduce the model size of the unit combination optimization problem, shorten the calculation time of the unit combination optimization, and then improve the reliability and robustness of the solution to the optimization problem; The application of the inventive method can increase the calculation speed of power grid energy-saving dispatching, improve the effect of energy-saving dispatching, reduce the operation loss of the power grid, thereby reduce carbon emissions, and achieve better energy-saving and environmental protection effects.

The invention discloses an agricultural drought remote sensing monitoring method, which comprises the following steps: 1) calculating enhanced vegetation index and land surface temperature according to surface reflectance and thermal infrared remote sensing images; 2) constructing an ETVDI model through the surface temperature and the enhanced vegetation index calculation result, and obtaining maximum value and minimum value of the surface temperature under the same enhanced vegetation index value and the number of pixel points at the points of same surface temperature values corresponding to different enhanced vegetation index values; and 3) carrying out polynomial fitting on the maximum value and minimum value corresponding to the same enhanced vegetation index value to obtain wet and dry boundary equations in the ETVDI model, and obtaining fitting parameters. The method overcomes the defect that a conventional TVDI model has vegetation index saturation easily in a dense vegetation area and the defect of uncertainty of wet and dry boundary equation fitting, thereby improving fitting precision; precision is higher in the expression aspect of temporal and spatial development of the drought; and the method can reflect the process of drought growing, development and elimination more truly, and provides reference for early warning and monitoring of the agricultural drought.

The invention discloses a gap nozzle boundary streamline determination method for creating a wide and thin water curtain. According to the method, a streamline gap nozzle model is mainly analyzed according to a hydromechanics plane potential flow theory, water flow entering a contraction section B from a parallel section A of a nozzle inlet is regarded as synthetic flow of parallel plane flow and point convergence, and flow from the contraction section B to a nozzle outlet is regarded as synthetic flow of the point convergence and the parallel plane flow; a specific potential function and a flow function are established, and a streamline boundary equation is deduced. According to the method for determining the boundary streamline of the gap nozzle for creating the wide and thin water curtain, the streamline boundary streamline of the gap nozzle is designed, the flow resistance loss of the gap nozzle is reduced, an internal flow field is optimized, and particularly, outlet speed distribution is homogenized.