磁性微球在水相中运动性质的表征

发布时间：2018-04-02 23:11

本文选题：磁性微球　切入点：磁响应性　出处：《重庆医科大学》2014年硕士论文

【摘要】：目前，磁性微球由于其独特的性质正成为研究热点。绝大部分磁性微球的应用环境为水溶液。磁性微球在水相的运动性能是其应用的关键性能指标。本文分析磁性微球在水相运动特点并测定相关参数。本文测量磁性微球在外加磁场的作用下对570nm光透过率变化,将透光率变化曲线转变为浊度变化曲线，，跟踪磁性微球运动过程。通分析磁性微球的受力，提出磁性微球在水相运动的力学模型；通过对大量粒子蒙特卡罗模拟、外加磁场强度分布模拟、粒子光散射计算，最小二乘拟合实验测定磁性微球在外部磁场下运动的浊度变化曲线，达到最好拟合的磁性微球参数组合代表其水相运动相关特征，藉此同步测定磁性微球水相运动性相关的特征参数。用此模型拟合分析水相磁性微球运动过程时，微球的饱和磁化强度和物理粒径之间有很强协方差，使得非线性最小二乘拟合时不收敛，但对应局部最好拟合的饱和磁化强度和粒径之间有明确规律性联系。先用常规非线性最小二乘拟合获得对应局部最好拟合的饱和磁化强度和物理粒径的关联函数；再用此函数限制两种参数的变化，拟合所记录的透过率变化曲线，能得到对应全局最优拟合的所需参数组合。用此特殊的迭代拟合方法所得磁性微球相关参数与其它方法所得大部分一致，少数磁性微球由于特殊原因拟合结果有偏差。通过对模型的验证及对算法的优化，该模型能够很好的计算出磁性微球在水相的表观粒径、磁化强度等与水相运动相关的性质，有望用于定量表征磁性微球，并用于指导磁性微球的设计和制备。
[Abstract]:At present, magnetic microspheres are becoming a research hotspot due to their unique properties.Most of the magnetic microspheres are applied in aqueous solution.The motion performance of magnetic microspheres in aqueous phase is the key performance index of its application.In this paper, the motion characteristics of magnetic microspheres in aqueous phase are analyzed and the relevant parameters are measured.The optical transmittance of magnetic microspheres to 570nm under the action of external magnetic field was measured. The change curve of transmittance was transformed into the turbidimetric change curve, and the motion process of magnetic microspheres was tracked.The mechanical model of magnetic microspheres in water phase is put forward by analyzing the force of magnetic microspheres, and the particle light scattering is calculated by Monte Carlo simulation of a large number of particles and the intensity distribution of magnetic field.The turbidity curve of magnetic microspheres moving under external magnetic field was measured by least square fitting experiment.The characteristic parameters related to the water phase movement of magnetic microspheres were measured synchronously.When the model is used to fit and analyze the motion of magnetic microspheres in aqueous phase, there is a strong covariance between saturation magnetization and physical particle size of the microspheres, which makes the nonlinear least square fitting not convergent.However, there is a clear correlation between saturation magnetization and particle size, which corresponds to the best local fitting.The correlation function of saturation magnetization and physical particle size corresponding to the local best fitting is obtained by the conventional nonlinear least square fitting, and then the variation of the two parameters is limited by this function to fit the recorded transmittance curve.The required parameter combinations corresponding to the global optimal fitting can be obtained.The correlation parameters of the magnetic microspheres obtained by this special iterative fitting method are mostly consistent with those obtained by other methods, and a few magnetic microspheres have deviations from the fitting results due to special reasons.Through the verification of the model and the optimization of the algorithm, the model can well calculate the apparent particle size and magnetization of the magnetic microspheres in the aqueous phase, which is expected to be used to quantitatively characterize the magnetic microspheres.It is used to guide the design and preparation of magnetic microspheres.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R943

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