Research On Two-dimensional Temperature Distribution Measurement Method Based On Magnetic Nanoparticles

Magnetic nanoparticles,as a new type of material,provide a new idea for non-invasive temperature measurement because of the temperature sensitivity of magnetization.Based on the single-point temperature measurement model of magnetic nanoparticles,a two-dimensional temperature measurement model of magnetic nanoparticles is established in this thesis.In this thesis,the influence of various factors on temperature measurement is analyzed,and a set of magnetic nanoparticle temperature measurement system is designed,and a series of experiments are carried out to verify the feasibility of the model.Firstly,the single-point and two-dimensional temperature measurement models of magnetic nanoparticles are introduced.This thesis introduces the static and dynamic magnetization theory of magnetic nanoparticles under excitation magnetic field,and summarizes the single point temperature measurement model,and converts the temperature measurement into the measurement of the first and third harmonic amplitude of magnetic response signal.A two-dimensional temperature measurement model of magnetic nanoparticles is proposed.The signal detected by the detection coil is the superposition and sum of the response signals of magnetic nanoparticles at the point to be measured and the surrounding points.By establishing the relationship model between the superposition signal and the signal of each magnetic nanoparticle point,the actual signal at the point to be measured can be reversely solved from the superposition signal,and the two-dimensional temperature measurement can be converted into the temperature measurement at a single point.Secondly,the influence factors of temperature measurement of magnetic nanoparticles are studied.In this thesis,the effects of truncation error,the amplitude andfrequency of excitation magnetic field,and the characteristics of magnetic nanoparticles on temperature measurement are analyzed.Finally,an experimental device for temperature measurement of magnetic nanoparticles is designed and the temperature experiment is carried out.The hardware measurement system mainly includes excitation magnetic field generator,weak magnetic field measurement device,signal conditioning circuit and differential detection coil to collect magnetic nanoparticle magnetization signal.The software system includes digital phase-sensitive detection algorithm and temperature inversion algorithm based on LabVIEW.By using this measuring system,the magnetic signal of magnetic nanoparticles can be collected and processed.The feasibility of the two-dimensional temperature measurement model is verified by experiments.