43results about How to "Flexible modeling" patented technology

The present invention relates to a synthetic aperture radar echo simulation method suitable for a plurality of emission signal waveforms. The method comprises the following steps: the step 1: setting radar emission signal waveform; the step 2: respectively performing the Fourier transform of each radar emission signal, and obtaining the radar emission signal frequency spectrum; the step 3: calculating a synthetic aperture radar transmission function; the step 4: multiplying the radar emission signal frequency spectrum obtained in the step 2 by the synthetic aperture radar transmission function obtained by the step 3, and obtaining the orientation time domain distance frequency domain spectrum of SAR echo signals; and the step 5: performing the inverse Fourier Transform of the obtained result along a distance frequency fr. The synthetic aperture radar echo simulation method suitable for a plurality of emission signal waveforms can flexibly select the emission signal waveform according to the real requirement to allow an SAR echo signal simulator to be more flexible and vivid for the modeling of the radar emission signals; and moreover, the modeling of the emission waveform, the radar work mode, the target scattering feature modeling and the modeling of the radar platform are relatively independent and have no mutual restriction.

The invention discloses a microwave passive circuit electromagnetic heat integral analysis method based on a spectrum element method. According to the method, firstly, a time domain spectrum element method is adopted for solving maxwell's equations, the instantaneous electric field and magnetic field distribution of a circuit under the effect of high-power pulses is worked out, and the electromagnetic loss at the current moment is obtained. If all of the electromagnetic loss inside a mold is converted into heat energy, the obtained heat energy is substituted into a heat conduction equation, and the temperature distribution conditions of each point at the current moment are obtained. Electricity characteristic parameters of materials at a next moment are obtained by utilizing a relational expression of dielectric parameters along with the temperature change, an electromagnetic field equation is calculated again, and the electromagnetic loss is obtained. The operation is repeatedly cycled in such a way until the preset heating time is completed. Through the electromagnetic heat integral analysis, the distribution condition of the temperature inside the mold along the time change when a filter receives the effect of different pulses can be clearly obtained, the modeling is flexible, the subdivision is convenient, formed matrixes have good sparsity, and the solving efficiency is higher.

The invention discloses an electric-heat integrated analysis method for a MESFET under the action of high-power electromagnetic pulses. The method comprises the steps that a drifting-diffusing equation set is solved by taking the electronic quasi Fermi potential, the hole quasi Fermi potential and the electric potential as variables and adopting a time domain spectral-element method to solve the instaneous quasi Fermi potential and electric potential of the metal-semiconductor field effect tube (MESFET) under the action of the high-power pulses, and then the electric field intensity and the current density at the moment are obtained; temperature distribution of all positions at the moment can be obtained under the action of a joule heat source by considering the influences of ambient environment temperature and heat convection; the carrier mobility and the generation-recombination rate are updated according to temperature changes, electric field distribution is recalculated, the steps are repeatedly conducted until the drifting-diffusing equation set meets the convergence precision, and electric field distribution and heat distribution at the moment are to-be-solved electric-heat distribution inside the MESFET at the moment. The method is achieved on the basis of a MESFET physical model, and the distribution conditions, changing along with time, of an electric field and the temperature in a device under the action of the high-power electromagnetic pulses can be clearly obtained.

The invention discloses an adaptive radiation dose calculation and simulation method for an irregular-shaped radiation source, which belongs to the field of nuclear facility decommissioning simulation. The invention includes establishing a three-dimensional geometric model of an object in three-dimensional modeling software and exporting it as an initial input; reading the three-dimensional model file of the object to obtain a grid model of the object; space division; using a cuboid to approximate the object model; An adaptive point kernel is generated from the overlapping part with the object; an adaptive point kernel is generated from the cuboid segmentation inside the object; the point kernel method is used to calculate the gamma radiation dose. The invention adopts the self-adaptive point kernel technology to improve the calculation efficiency, and can adjust the distribution density of the point kernel according to the position of the detection point to meet the requirements of radiation dose calculation time and accuracy, and can process any shape geometry, so that the modeling of the dose evaluation can be achieved. , The calculation process is more flexible and efficient.

The invention relates to a method (10) for charge detection in a cylinder of an internal combustion engine, wherein the cylinder is connected to an intake manifold via an intake valve and to an exhaust duct via an exhaust valve. The method (10) includes the step of providing (102) a database having information related to the exhaust gas back pressure (p ag ) data sets related to the amount of aeration components, wherein the step of providing (102) the database comprises: providing (100) measurement data (30) measured at the test bench, and providing (101) the calculated by means of ventilation calculations The simulated data (31) of , determine (103) the basic function (20) that qualitatively describes the relationship between the amount of charge components and the exhaust back pressure (p ag ) and adapt (104) the base function (20) to at least one data set of the database by appropriate selection of variable parameters of the base function (20).