This substrate for a magnetic recording medium has a metal structure made of an Al alloy having a composition including Si in a range of 28.0% by mass to 32.0% by mass, Cu in a range of 2.5% by mass to 4.0% by mass, and Mg in a range of 0.8% by mass to 1.5% by mass with a remainder being Al, primary-crystal Si particles having a maximum diameter of 0.5 m or more and an average particle diameter of 2 m or less are dispersed in the metallic structure, a diameter of the substrate is in a range of 53 mm to 97 mm, and a thickness of the substrate is in a range of 0.2 mm to 0.9 mm.

This aluminum alloy substrate for a magnetic recording medium has a metal structure made of an Al alloy having a composition including Si in a range of 18.0% by mass to 22.0% by mass, Ni in a range of 5.0% by mass to 8.5% by mass, Cu in a range of 2.5% by mass to 4.0% by mass, and Mg in a range of 0.8% by mass to 1.5% by mass with a remainder being Al, a primary-crystal Si precipitate having a maximum diameter of 0.5 m or more and an average particle diameter of 2 m or less is dispersed in the metal structure, a diameter is in a range of 53 mm to 97 mm, and a thickness is in a range of 0.2 mm to 0.9 mm.

This aluminum alloy substrate for a magnetic recording medium has a metal structure made of an Al alloy having a composition including Si in a range of 18.0% by mass to 22.0% by mass, Ni in a range of 5.0% by mass to 8.5% by mass, Cu in a range of 2.5% by mass to 4.0% by mass, and Mg in a range of 0.8% by mass to 1.5% by mass with a remainder being Al, a primary-crystal Si precipitate having a maximum diameter of 0.5 m or more and an average particle diameter of 2 m or less is dispersed in the metal structure, a diameter is in a range of 53 mm to 97 mm, and a thickness is in a range of 0.2 mm to 0.9 mm.

A method of producing an oppositely magnetized magnetic structure within or on a substrate material includes: First and second numbers of cavities are generated within or on a substrate material and are filled with first and second hard magnetic materials, respectively, exhibiting first and second coercive field strengths, respectively, so as to produce first and second arrangements of hard magnetic structures, respectively, the second coercive field strength being smaller than the first coercive field strength.

The first and second arrangements of hard magnetic structures are magnetized in a first direction by a first magnetic field exhibiting a field strength which exceeds the first and second coercive field strengths.

The second arrangement of hard magnetic structures is magnetized in a second direction, which differs from the first direction, by a second magnetic field exhibiting a field strength which falls below the first coercive field strength but exceeds the second coercive field strength. Magnetizing the second arrangement of hard magnetic structures includes exposing the first and second arrangements of hard magnetic structures to the second magnetic field.

Thermally annealed superparamagnetic core shell nanoparticles of an iron-cobalt alloy core and a silicon dioxide shell having high magnetic saturation are provided. A magnetic core of high magnetic moment obtained by compression sintering the thermally annealed superparamagnetic core shell nanoparticles is also provided. The magnetic core has little core loss due to hysteresis or eddy current flow.

Magnet array structure includes a first linear magnet array and a second linear magnet array having a first and a second arrangement of magnets, respectively, in which the first and the second arrangement of magnets are repeated along respective lengths of the first and second linear magnet array. The first and second arrangement of magnets include respective individual first and second magnet elements arranged along the respective length of the first and second linear magnet array so that no net magnetic forces parallel to the length of the first and second linear magnet array result on the first and second arrangement of magnets, respectively. The first arrangement of magnets is offset from the second arrangement of magnets so that the first arrangement of magnets and the second arrangement of magnets partially overlap.

A method for preparing coated metal nanoparticles, each nanoparticle comprising a core constituted of at least one metal M and a layer constituted of at least one polymer, the layer coating the metal core. The method comprises the steps: (a.sub.1) preparing a solution A comprising the at least one metal M in the form of cations M.sup.n+, n being an integer comprised between 1 and 3, each metal M being a transition metal of atomic number comprised between 21 and 30, a polyol, and a noble metal salt; (a.sub.2) preparing a solution B comprising at least one organic monomer of the at least one polymer, in an organic solvent; (b) mixing solutions A and B, this mixture being heated to the boiling temperature of the polyol; and (c) recovering the coated metal nanoparticles.

A secured device includes an electronic component and a protective cover surrounding the electronic component. The secured device also includes one or more chemiluminescent reactant layers and a light sensor that is electrically connected to the electronic component. The one or more chemiluminescent reactant layers are disposed between the protective cover and the electronic component and include multiple reactants that undergo a chemiluminescent reaction. The light sensor is configured to trigger one or more tamper response operations responsive to detection of a photon generated by the chemiluminescent reaction.

A nano magneto-rheological fluid, comprising nano-scale magnetizable magnetic particles, wherein an average particle size or a minimum size in one dimension is less than 100 nanometers; and fluids used as carrier liquids, wherein the magnetic particles are dispersively distributed in the fluids. An apparatus for making the nanometric magnetorheological fluid including a ball mill, a settling separator located downstream of the ball mill for receiving the primary magnetic particles, a magnetic separator located downstream of and connected to the settling separator for receiving the upper layer of fluid containing fine magnetic particles, and an agitator for mixing the desired secondary magnetic particles with a carrier liquid and an additive. A method for making the nano magneto-rheological fluid wherein the nano magneto-rheological fluid has performance advantages such as no remanent magnetization, non-settlement, low viscosity, low abrasive rate for components, long service life, high reliability and fast and clear response.

The present application relates to a composition for 3D printing, a 3D printing method using the same, and a three-dimensional shape comprising the same, and provides a composition for 3D printing capable of embodying a precise formation of a three-dimensional shape using a ceramic material and a uniform curing property of the three-dimensional shape.