7 results about "Relaxation process" patented technology

The invention discloses a method for enhancing up-conversion avalanche nonlinearity based on metal ion regulation sublattice, which comprises the following steps: S1, selecting crystal matrix doped up-conversion avalanche activator ions as activation ions for realizing up-conversion avalanche nonlinearity; s2, co-doping one or more non-luminous metal ions on the basis of the activator ion-doped crystal matrix obtained in the S1 to replace matrix cations in the crystal matrix so as to complete sublattice shrinkage; s3, sublattice shrinkage in S2 acts on activating agent ions, so that the average physical distance of activating agent ion pairs in the system is shortened, and the efficiency of a specific cross relaxation process beneficial to upconversion avalanche nonlinearity is improved by shortening the ion spacing. Compared with the prior art, the method has the advantages that the population rate of a key intermediate energy level is enhanced, so that avalanche nonlinearity of up-conversion emission is greatly improved in a measurable manner, and the limitation of traditional up-conversion energy transfer efficiency and avalanche nonlinearity regulation is broken through.

The invention provides a trap level measurement method considering temperature rise rate thermal stimulation current, and belongs to the technical field of insulating materials. ET is calculated according to the change relation of the peak temperature Tm along with the heating rate beta. The TSDC curve often has overlapped peaks, the parameter of a single peak is difficult to accurately extract in the TSDC curve with a single heating rate, and the method of changing beta can effectively distinguish the peaks in different dynamic processes by tracking the change track of Tm of each peak along with beta, so that respective ET is calculated respectively. According to the method, the dependence on the current peak shape is remarkably reduced, the identification and analysis capability of overlapped peaks is improved, and whether the relaxation process has single activation energy or not can be judged, so that more reliable and more accurate characterization of the trap energy level is realized.

The invention relates to a multi-physical mechanism coupled stress relaxation local modeling method, which comprises the following steps of: S1, solving a microstructure state variable under a current stress condition through a microstructure evolution equation by taking initial microstructure information and a loading condition as input parameters; s2, on the basis of the updated microstructure state variable, the current plastic relaxation rate is updated in combination with a thermal-mechanical coupling stress relaxation kinetic equation, and the elastic relaxation amount and the relaxation stress under the current relaxation amount are solved; s3, recalculating the next increment step by taking the updated relaxation stress and microstructure information as new input parameters, namely circularly executing the steps S1-S2 until the expected solving time is reached, and outputting microstructure evolution information and time-varying relaxation stress information in the whole relaxation process; the problems that a current prediction model about stress relaxation basically comes from experimental data secondary processing, and relaxation stress prediction of a key structure material serving in complex loading or important occasions is limited are solved.

The invention discloses a non-contact characterization method and measurement system for bolt cross-elastoplastic stage relaxation based on third-order perturbation sound modulation, a storage medium and a program product, and the method comprises the steps: sequentially applying low-frequency pumping signals with different amplitudes and high-frequency detection signals with a constant amplitude through an incremental pumping excitation strategy; third-order nonlinear vibration sound modulation response of the bolt connection structure is excited; collecting a vibration response signal of the bolt connection structure by using a non-contact laser vibration meter, performing spectral analysis, extracting amplitudes of a fundamental wave and a first-order sideband signal, calculating a nonlinear index beta, and analyzing the concave-convex characteristic of the beta along with the change of the pumping excitation voltage; distinguishing an elastic relaxation stage and an elastic-plastic relaxation stage of the bolt according to the concave-convex characteristics of the beta curve; a correction modulation index gamma is constructed based on changes of the beta curve under different excitation voltages, and monotonous quantitative characterization of the bolt pre-tightening force in the relaxation process from the elastic-plastic stage to the elastic stage is achieved. The method has the advantage that the continuous, monotonous and quantitative characterization of the whole process from elastoplasticity to elastic relaxation of the bolt is realized.

The invention relates to the technical field of vehicles, in particular to a battery internal temperature estimation method and device, a vehicle, a medium and a program product. The method comprises the following steps: collecting dynamic response data of a to-be-estimated battery; calculating instantaneous ohmic internal resistance, a relaxation process time constant and characteristic frequency impedance based on the dynamic response data to be estimated, and constructing a comprehensive characteristic vector according to the instantaneous ohmic internal resistance, the relaxation process time constant and the characteristic frequency impedance; the vector is input to a pre-trained temperature estimation model, the internal temperature of the to-be-estimated battery is output through the pre-trained temperature estimation model, and the pre-trained temperature estimation model is obtained by training a preset machine learning model through the dynamic response data of the multiple target batteries in the full temperature range and the full life cycle. Therefore, the problems of incapability of capturing real-time temperature rise and local overheating of the battery, lack of mass production feasibility, lack of robustness and reliability, high cost and limited estimation precision in related technologies are solved, and the safety is improved.

The invention relates to the technical field of solid propellants, and discloses a solid propellant relaxation process microscopic damage in-situ characterization method based on micron CT, and the method comprises the following steps: S100, preparing a propellant sample; s200, clamping and fixing the propellant sample on a micro material testing machine; s300, the micro material testing machine and a micron CT rotary table are connected in a positioning and fastening mode, it is ensured that the propellant sample and an upper clamp and a lower clamp of the micro material testing machine are located on the same vertical axis, a real-time dynamic imaging mode of micron CT is used, the rotary table is rotated, and the propellant sample is observed; s400, carrying out tensile loading on the propellant sample by adopting a tensile loading mode of a micro material testing machine until the propellant sample is broken, and recording a corresponding force-displacement curve; and S500, replacing the propellant sample, repeating the steps S200 to S400, and judging that the relaxation test is finished until the stress is constant.

The application discloses a method for constructing a mechanical model of high polymer rheological behavior considering temperature effect, and specific steps are as follows: S1, a temperature-dependent fractional derivative constitutive model is established according to the change of high polymer viscoelastic properties in a creep or relaxation process; S2, a linear relationship between a fractional order alpha of the temperature-dependent fractional derivative constitutive model and temperature T is constructed; S3, a function relationship between material parameters E of the temperature-dependent fractional derivative constitutive model and temperature T is constructed; and S4, the change of mechanical properties of the high polymer in the creep or relaxation process at different temperatures is described by using the established temperature-dependent fractional derivative constitutive model, and model parameters are determined by fitting experimental data. α The application provides a temperature-dependent fractional derivative constitutive model which is convenient to apply, clear in physical concept and capable of meeting accuracy requirements, so as to solve the problem that there is no simple and high-precision theoretical model for describing the temperature-related rheological behavior of high polymers.