Preparation of NiZn-ferrite nanofibers by electrospinning for DNA separation

We present the synthesis, magnetic and UV spectrometry of NiZn-ferrite nanofiber. The single phase of spinel ferrite was obtained at 600 °C. The NiZn-ferrite fibers fabricated by an electrospinning process were formed as a polygonal grain growth with firing temperature in fiber matrix. It appeared that the saturation magnetization (M_S) of NiZn-ferrite nanofiber was dependent on Ni/Zn molar ratio which is similar to that of the inverse spinel ferrites. The NiZn-ferrite fibers showed good DNA adsorption efficiency that can be modified and utilized for DNA separation with magnetic nanofiber as a novel material in clinical applications.     

飞轮储能器的新型高温超导悬浮轴承研究

储能器是一种储存能量的装置,随着高温超导悬浮轴承运用到飞轮储能器中,储能效率得到了大大的提高。它的主要结构是由高温超导体和永磁体组成。文中提出一种全新高温超导悬浮轴承,并研究其的力学性能,为新型超导悬浮轴承的研究与开发做好了基础准备。     

Reargument over E ～ j relation of high temperature superconductors

The E ∼ j relation of an HTSC slab is solved strictly within the Bean’s model in two different situations where the system does and does not reach equilibrium state under the magnetic relaxation respectively, with both forward and backward hopping taken into consideration (the backward hopping means the hopping from the barriers with low energy to high ones). Our results suggest and rigorously prove that the In E ∼ In j curves show only positive curvature on the side of slab where the directions of current-created field and the applied field are the same, while they show both positive and negative curvatures at a certain field range on the other side where the directions are opposite. The relationship of the positive and negative curvatures with the critical current, applied field and temperature is also discussed.     

从电磁感应定律看负磁导率的产生过程

以左手材料中产生负磁导率的开口谐振环结构模型为例,从磁导率的定义出发,借助于电磁感应定律,推导了负磁导率的产生过程.     

Ultrafast photo-induced turning of magnetization and its relaxation dynamics in GaMnAs

We report that,by linearly polarized pumping of different wavelengths,Kerr transients appear at zero magnetic field only in the case when GaMnAs samples are initialized at 3 K by first applying a 0.8 Tesla field and then returning to zero field.We find that,instead of magnetization precession,the near-band gap excitation induces a coherent out-of-plane turning of magnetization,which shows very long relaxation dynamics with no precession.When photon energy increases,the peak value of the Kerr transient incre...     

Thermodynamic approach of spin-state excitations in LaCoO3

Magnetic susceptibility and heat capacity due to spin-state excitations in LaCoO₃ were analyzed with an irregular solution model composed of Co³⁺ ions in the low-spin ground state and in the high-spin excited state. An energy-levels diagram proposed by Ropka and Radvanskii [1] was used for the high-spin excited state. This analysis showed that the entropy of mixing is less than that of ideal solutions and the enthalpy of mixing is negative, indicating that the high-spin Co ions are arranged as far apart as possible.