【作者】 邵海成；

【导师】 李世普；

【作者基本信息】 武汉理工大学 ， 材料物理与化学， 2005， 硕士

【摘要】 目前,组织细胞经液氮冷冻后,在37-40℃热水中1分钟左右解冻,几乎所有的解冻局限用热水解冻。经过几十年的考虑,人们越来越认识到解冻过程的重要性。因此,利用纳米铁氧体磁性粒子建立组织细胞复苏新方法是本研究的主要目的。 研究确定了纳米铁氧体磁性材料的制备工艺;以化学共沉淀法合成能够在交变磁场环境下生热的MeFe₂O₄型磁性材料和用滴定水解法制备Fe₃O₄材料。保证Fe³⁺/Me²⁺=2;然后,在高速搅拌的作用下缓慢加入到6M的NaOH溶液中,调节适当的搅拌速度（3000r/min左右）和pH（11-13）值,搅拌30min后,将合成的悬浮液在沸水浴中浸渍2h;再用去离子水水洗沉淀10余次,直至pH为6.5-8为止。过滤后得到褐色沉淀,最后将沉淀部分在100℃热处理2h后得到MeFe₂O₄纳米颗粒。并对制得的材料进行X射线衍射测试、透射电镜观察颗粒的形貌及大小、颗粒的粒径分析以及磁滞回线的测试。并对不同材料的结果进行对比分析,然后进行材料的选择。 在制得铁氧体纳米粒子以后,要使颗粒均匀的悬浮在溶液中,因此要对颗粒进行表面修饰。本实验利用表面活性剂油酸钠对钴铁氧体纳米颗粒进行表面改性,使颗粒均匀的悬浮在溶液中。然后比较表面改性前后的沉降时间,粒度大小和ξ电位,并确定表面活性剂的用量。 研究了CoFe₂O₄纳米悬浮液在交变磁场作用下的热效应,将制得的CoFe₂O₄纳米悬浮液以不同的浓度:0,0.5,1.0,2.0,4.0 mg/mL在一定的交变磁场作用下测定温度随时间的改变;然后用浓度为2 mg/mL的CoFe₂O₄纳米悬浮液在不同输出功率的交变磁场下测定温度随时间的改变。更多还原

【Abstract】 At present, almost all cells defrost in warm water after rhagiocrine cells were froze by liquid nitrogen, it spends about one minute to defrost in 37-40℃ water. People have more and more realized the importance of defrost process through many years.In this paper, ferrite magnetic nanoparticles preparation technologies were studied. MeFe₂O₄ nanoparticles were synthesized by coprecipitation method and prepared Fe₃O₄ nanoparticles by the titration hydrolyzation method. To sure the Fe³+/Me²+=2, the aqueous mixture was added into a 6M NaOH solution drop-by-drop to form a precipitate. Adjust suit stir speed （about 3000r/min） and pH （11-13） value. After 30 minutes, the slurry was then placed in a boiling water bath and digested for two hours. After the digestion, the slurry was filtered and washed more than 10 times until the pH in the solution became neutral. Then got the brown powder was heat-treated at 100℃ for two hours, the suit treatment after cold was carried out and got the MeFe₂O₄ nanoparticles. At the same time, it studied by X-ray diffraction, TEM photographs, particle size analysis and magnetic properties test. Then analyzed every material results and selected the best one.In order the particles suspend in solution uniformly, it need to modify the surface of nanoparticles by surfactant. This test used sodium oleate surfactant to modify the surface of CoFe₂O₄ nanoparticles. Then compared the sedimentation time, particle size and zeta potential with the before modified one.CoFe₂O₄ nanoparticles suspension heating effect under the alternating magnetic field was studied in this paper. Vary CoFe₂O₄ nanoparticles suspension concentration were prepared, 0, 0.5, 1.0, 2.0, 4.0 mg/mL then measured the temperature changed with time in the certain alternating magnetic field. At the same time, measured 2 mg/mL CoFe₂O₄ nanoparticles suspension concentration temperature and time in differ alternating magnetic field.更多还原