Design Of Magnetic Nanoparticles Characteristic Measurement System

Since its inception,nanomaterials have been widely used due to their excellent properties.In recent years,magnetic nanoparticles have shown promising applications in the field of non-contact temperature measurement.Research and measurement of the properties of magnetic nanoparticles is of great significance to the promotion of its application.In this thesis,a magnetic nanoparticle property measurement system is designed,which can measure the AC magnetic susceptibility and particle size distribution of the sample,and promote the application of magnetic nanoparticles.First of all,based on the study of magnetic susceptibility,relaxation model and particle size distribution model of magnetic nanoparticles,a magnetization measurement model based on differential coil was designed.The model was used to measure AC susceptibility and particle size distribution.Subsequently,the hardware platform of the measurement system is introduced in detail.A suitable solenoid is used to generate the excitation magnetic field,and a multi-turn coil wound by a thin copper wire is used as a sensor to detect a weak magnetic signal,and the weakening signal is amplified and filtered by a signal conditioning circuit.The calibration circuit was designed to calibrate the system.For the software control platform,this thesis proposes to use c# language for programming,integrating the measurement process of multiple features.Modular programming is used to encapsulate important algorithms such as PID algorithm,DPSD algorithm,global optimization algorithm,etc.,and different methods are used to implement different processing of sampled data to obtain different characteristic parameters.At the same time,using the hybrid method,combined with c# excellent interface development capabilities and matlab's powerful numerical computing capabilities,improve programming efficiency.Finally,the magnetic susceptibility measurement and particle size distribution measurement were carried out using magnetic particle samples with different particle sizes,and the experimental results were compared with the theoretical results to verify the reliability of the measurement system.