ZnFe2O4基磁凝胶的制备及磁性

用自形成法制备ZnFe2O4磁凝胶,并进一步研究包裹ZnFe2O4的γ-Fe2O3磁凝胶的制备,用振动样品磁强计(VSM)对ZnFe2O4和包裹ZnFe2O4的γ-Fe2O3磁性微粒及配制的胶体处在溶胶和凝胶的磁性测量.结果表明ZnFe2O4磁性微粒和胶体呈顺磁性,而包裹ZnFe2O4的γ-Fe2O3磁性微粒和胶体呈亚铁磁性.ZnFe2O4凝胶较其溶胶易磁化,而ZnFe2O4/γ-Fe2O3凝胶较其溶胶难磁化.从微观机制上解释了产生这些磁性差异的原因.

Abstract：

ZnFe2O4 magnetic gel is prepared by the self-formed method, and the preparation of γ-Fe2O3 coated with ZnFe2O4 is studied. The magnetization of ZnFe2O4 and γ-Fe2O3 nanoparticles coated with ZnFe2O4 and their gels and sols are measured by a vibrating sample magnetometer(VSM). The results show that the ZnFe2O4 powder and its colloid are paramagnetic, while the γ-Fe2O3 magnetic particles coated with ZnFe2O4 and colloid show ferrimagnetism. ZnFe2O4 gel is easier to be magnetized than sol. However, ZnFe2O4/γ-Fe2O3 gel is harder magnetized than sol. The reason for the difference in magnetization is interpreted microscopically.     

抗水解稳定离子钛对烤烟生长发育和品质的影响

[目的]研究抗水解稳定离子钛对烤烟生长发育和品质的影响,为优质烟叶生产技术提供理论依据。[方法]在不同时期采用不同方式对烤烟施用抗水解稳定离子钛,研究烤烟田间生长状况、常规化学成分和致香物质含量的变化。[结果]施用抗水解稳定离子钛可以显著促进烤烟的生长发育,处理T7[移栽时喷施叶面肥(1∶1 000)+移栽后30 d喷施叶面肥(1∶1 000)]促进效果最明显。处理T_6[移栽时喷施叶面肥(1∶1 000)+移栽后30 d(团棵期)喷施叶面肥(1∶600)]的总糖、还原糖和总氮含量均接近优质烟叶的要求,降低上部叶和中部叶的烟碱含量,提高烤烟中部叶钾含量。处理T_5[移栽时喷施叶面肥(1∶1 000)+移栽后30 d(团棵期)喷施叶面肥(1∶200)]的总糖、还原糖含量也较适宜,同时处理T_5可以显著增加上部叶钾含量,提高烟叶可用性。处理T_7总糖和还原糖含量偏高,不利于烤烟烘烤质量的体现。[结论]总体来看,处理T_6效果最好,T5次之。     

二元CoFe2O4-p-MgFe2O4磁性液体的制备及磁化特性研究

采用化学共沉淀法制备了CoFe2O4强磁性纳米微粒和p-MgFe2O4(Mg(OH)2与Fe(OH)3的混合物)弱磁性纳米微粒.并按体积比为1:1将CoFe2O4磁性液体、p-MgFe2O4顺磁磁性液体混合,得到二元CoFe2O4-p-Mg-Fe2O4磁性液体.实验结果表明混合磁性液体的磁化强度不能简单等于两种单一磁性液体磁化强度的叠加.在CoFe2O4磁性液体中,其磁性微粒在无场时会自发组装形成对磁化强度无贡献的闭合环状团聚体结构.二元磁性液体磁化时,这种CoFe2O4微粒环可能部分破裂.根据偶极子相互作用能判断CoFe2O4体系与p-MgFe2O4体系无相互作用,因此可根据单元磁性液体的磁化性质为基础来分析二元磁性液体的磁化性质.

Abstract：

Strong magnetic CoFe2O4 nanoparticles and weak magnetic p-MgFe2O4 (mixture of hydroxide Mg(OH)2 and Fe(OH)3) nanoparticles are produced by the chemical co-precipitation technology. Binary ferrofluids of CoFe2O4-p-MgFe2O4 are obtained by mixing CoFe2O4 ferrofluids and p-MgFe2O4 paramagnetic fluids in a ratio of 1: 1 (v/v). The experimental results indicate that the magnetization of the binary ferrofluid is not simple summation of the two single magnetic fluids. Without external magnetic field,some particles can self-assemble into aggregates of closed ring-like structures, which make no contribution to the magnetization for the CoFe2O4 ferofluid. In the magnetization process of the binary ferrofluid, the closed ring-like structure can partially break. Based on the interaction between two dipoles, it can be judged that there is no magnetic interaction between the CoFe2O4 magnetic system and the p-MgFe2O4 magnetic system. Therefore, the magnetization behavior of the binary ferrofluids can be analyzed based on the single magnetic fluids.     

干湿交替处理对烟苗素质的影响与分析

在中棚内和大棚内进行干湿交替结合碘钨灯增温增光培育烟苗,并与中棚和大棚内常规漂浮育苗进行比较.结果表明,干湿交替处理的成苗根系发达,茎秆粗壮,茎高和干物质积累居中;碘钨灯处理的烟苗长势较快,可增加苗期积温,但对干物质的积累无增加作用.干湿交替处理结合碘钨灯增温可使烟苗成苗期提前,培育健壮发达的根系,但对烟苗的有效叶数无明显增加.     

制备γ-Fe2O3纳米微粒的一种新方法

提出了两次反应制备γ-Fe2O3纳米微粒的新方法.制备过程中通过控制第2次反应中NaOH的浓度实现了由结晶的FeOOH逐渐转化为结晶的γ-Fe2O3纳米微粒.用X射线衍射仪(XRD)、透射电子显微镜(TEM)和振动样品磁强计(VSM)分别对纳米微粒的晶体结构、形态和大小、磁化强度进行表征.实验结果表明,γ-Fe2O3纳米微粒具有高结晶性,形状近似为球形,饱和磁化强度达63.90 A·m2/kg,是γ-Fe2O3块体饱和磁化强度的84.1%.