The system for modulating the activity of cells according to an exemplary embodiment of the present invention may include a rotating magnetic field generating device which has an internal space in which a magnetic force generating unit and a living body can be disposed and forms a rotating magnetic field which satisfies Relationship Formulas 1 and 2 below; and magnetic particles disposed in the living body and capable of binding to a bioactive material and generating a torque when a rotating magnetic field is applied to transmit the torque to the bioactive material.

|M.sub.c|≥1 mT  [Relationship Formula 1]

|M.sub.75−M.sub.c|/D.sub.75≤5.0 T/m  [Relationship Formula 2]

In Relationship Formulas 1 and 2 above, M.sub.c is the strength of the magnetic field at the position of the rotation axis, D.sub.75 is the distance from the rotation axis to the 75% position of the distance to the magnetic force generating unit, and M.sub.75 is the strength of the magnetic field at the position D.sub.75.

Superparamagnetic nanocomposites are provided. In an embodiment, a superparamagnetic nanocomposite comprises a superparamagnetic core comprising a first, soft superparamagnetic ferrite and a superparamagnetic shell comprising a second, soft superparamagnetic ferrite, the shell formed over the core, wherein the first and second soft superparamagnetic ferrites are different compounds and have different magnetocrystalline anisotropies.

Disclosed herein is a permanent magnet comprising: a plurality of aligned iron nitride nanoparticles wherein the iron nitride nanoparticles include α″-Fe.sub.16N.sub.2 phase domains; wherein a ratio of integrated intensities of an α″-Fe.sub.16N.sub.2 (004) x-ray diffraction peak to an α″-α″-Fe.sub.16N.sub.2 (202) x-ray diffraction peak for the aligned iron nitride nanoparticles is greater than at least 7%, wherein the diffraction vector is parallel to alignment direction, and wherein the iron nitride nanoparticles exhibit a squareness measured parallel to the alignment direction that is greater than a squareness measured perpendicular to the alignment direction.

Disclosed herein is an apparatus for imaging nano magnetic particles using a 3D array of small magnets. A field-free region generation apparatus includes a hexahedral housing having an opening formed in the first surface thereof such that a measurement head is inserted into a spacing area, a pair of rectangular-shaped magnets installed respectively on two surfaces facing each other, among four surfaces perpendicular to the first surface of the housing, and a pair of magnet arrays installed respectively on the first surface of the housing and on another surface facing the first surface, each of the magnet arrays including multiple small magnets arranged along the edge of the opening.

A method includes converting ˜9 nm soft-magnet Al—CoPt into a hard-magnet L1.sub.0-CoPt, acid etching the hard-magnet L1.sub.0-CoPt, and annealing the acid etched hard-magnet L1.sub.0-CoPt to generate a L1.sub.0-CoPt/Pt catalyst.

A method of producing a magnetic powder includes: performing heat treatment on first particles that contain triiron tetraoxide to prepare second particles that contain ε-iron oxide.

The present invention relates to a method for producing a magnetic powder, including: preparing a precursor solution containing an iron precursor and a silica precursor; spraying the precursor solution to form iron/silica precursor droplets; drying the iron/silica precursor droplets to produce iron/silica precursor particles; and heat treating the iron/silica precursor particles to produce an iron oxide/silica composite powder in which iron oxide particles are embedded in a silica matrix. The present invention also relates to a magnetic powder produced by the method. The present invention may provide an iron oxide magnetic powder that does not use rare earth elements and a method for producing the same.

Provided is an ion-conducting layer including: an ion conductive matrix; and a 1D composite dispersed in the ion conductive matrix and oriented in a membrane thickness direction, in which the 1D composite includes a core of a non-conductive 1D nanostructure; an intermediate layer enclosing the core and having magnetic nanoparticles bonded to a surface thereof; and a surface layer conducting the same kind of ions as ions in the matrix.

Disclosed herein is a permanent magnet comprising: a plurality of aligned iron nitride nanoparticles wherein the iron nitride nanoparticles include α″-Fe.sub.16N.sub.2 phase domains; wherein a ratio of integrated intensities of an α″-Fe.sub.16N.sub.2 (004) x-ray diffraction peak to an α″-α″-Fe.sub.16N.sub.2 (202) x-ray diffraction peak for the aligned iron nitride nanoparticles is greater than at least 7%, wherein the diffraction vector is parallel to alignment direction, and wherein the iron nitride nanoparticles exhibit a squareness measured parallel to the alignment direction that is greater than a squareness measured perpendicular to the alignment direction.

A plasmonic nanostructure material having semiconductor nanocrystals or metal-oxide nanocrystals configured with point defects to provide localized surface plasmon resonance as a parameter for tuning the electronic structure of the nanocrystals. A method of preparing a plasmonic nanostructure material including: colloidal synthesis of nanocrystals to provide point defects resulting in localized surface plasmon resonance as a parameter for tuning the electronic structure of the nanocrystals; and depositing nanocrystals as a thin film, growing nanocrystals on a desired substrate, or drawing nanocrystals into a nanowire.