磁性复合材料在固相萃取食品中环境类雌激素的应用进展EI北大核心CSCD

环境类雌激素作为食品中一类典型的污染物,严重影响人体内分泌系统的功能与代谢。磁性固相萃取因其简洁高效、富集倍数高、适用范围广等优点,已被广泛应用于食品中环境类雌激素的富集检测。Fe_(3)O_(4)纳米粒子作为经典的磁固相萃取材料,易于形成大分子团聚物,影响其选择吸附性能,限制了磁固相萃取技术在食品中环境类雌激素的痕量分析。新兴的磁性复合材料可有效地解决上述问题,已成为磁固相萃取技术的研究热点之一。本文综述了近5年来新兴的磁性聚合物复合材料、磁性碳基复合材料和磁性金属-有机骨架复合材料在食品中环境类雌激素富集检测的应用进展。     

An effect of particle size on the behavior of ferromagnetic materials

The dependence of magnetic behavior of media upon the particle/grain size is studied here. A model is presented to describe the behavior of nanomagnetic materials as a function of particle size. The model is applied to two types of experiments: (1) the decay rate of the magnetic aftereffect in nanomagnets and (2) the variation of spontaneous magnetization versus temperature. Both of these experiments show a deviation from the behavior of bulk media above a critical temperature.     

Investigation of shape-dependent switching of coupled nanomagnets

This paper presents a magnetic force microscopy study of antiferromagnetic ordering along chains of dipole-coupled single-domain permalloy nanomagnets with a variety of shapes. Magnetization reversal processes occur due to antiferromagnetic coupling between the closely spaced dots when an appropriate external magnetic field is applied. The goal of this study was to investigate the switching properties and correlation lengths as a function of nanomagnet geometry. We have found that certain shapes (due to their stronger stray fields) clearly show stronger interaction than others when the chain is demagnetized. In addition we have seen that the performance of the nanomagnets also depends on the method of demagnetization, and this fact must be taken into account when shape engineering is used to design coupled nanomagnet systems for a given application.