Described herein is a method for producing ferrite nanocrystals. The method includes providing a solution including a fatty acid, an aliphatic amine and an alcoholic solvent, adding at least one organometallic precursor compound including a metal selected from the group consisting of Fe, Mn, Co and Zn and an aromatic organic molecule to the solution thereby obtaining a reaction mixture, transferring the reaction mixture to a sealed reactor, thereby obtaining a filling percentage of the sealed reactor between 20 and 70 vol. %, and heating the sealed reactor to a temperature between 160° C. and 240° C. for at least 3 hours.

The present invention refers to material comprising a compound of the formula ABOx wherein x is >1.5 and ≤2.5, A is independently selected from a transition metal of IUPAC groups 10 and 11, and B is independently selected from a transition metal of IUPAC group 6, 7, 8 or 9 or a main group element of IUPAC group 13, as highly active catalyst for hydrogen evolution reaction (HER).

Embodiments include a magnetic recording medium containing ε-type iron oxide particles and having excellent SNR, a manufacturing method of ε-type iron oxide particles, and a manufacturing method of a magnetic recording medium. High SNR is achieved by a magnetic recording medium containing ε-type iron oxide particles, in which a coefficient of variation of an aspect ratio of the ε-type iron oxide particles is equal to or smaller than 18%, and a squareness ratio of the magnetic recording medium measured in a longitudinal direction of the magnetic recording medium is higher than 0.3 and equal to or lower than 0.5. The object is also achieved by the application of the magnetic recording medium.

A method for preparing copper-nickel cobaltate nanowires includes steps of: (1) dissolving a soluble nickel salt, cobalt salt and copper salt in ultrapure water, and preparing same into a mixed salt solution A; (2) adding 1-4 mmol of sodium dodecyl sulfate to solution A, and dissolving same with stirring; (3) dissolving 12-30 mmol of hexamethylenetetramine in 20 mL of ultrapure water to form solution B; (4) slowly dropwise adding solution B to solution A via a separatory funnel to form solution C, and stirring same for 0.5-1 h; and (5) further transferring same into a 100 mL reaction vessel, reacting same at 100-160° C. for 8-20 h, suction filtration and washing, and drying same at 40-60° C. in a vacuum oven, and further reacting same at 350-800° C. for 1-4 h in a muffle furnace.

The present disclosure relates to a magnetic heating element, an induction heating-type adhesive including the same, and a method of preparing the magnetic heating element. The magnetic heating element according to an embodiment of the present disclosure has a composition with an atomic ratio represented by the following formula, (Ma1-x-yMbxFey)1Fe2-zMczO4, wherein: Ma is cobalt (Co), Mb is one or more of zinc (Zn), Copper (Cu), Manganese (Mn), and Magnesium (Mg), and Mc is one or more of samarium (Sm), yttrium (Y), cerium (Ce), europium (Eu), neodymium (Nd), and dysprosium (Dy); 0.01≤x<0.6, 0≤y≤0.4, x+y<1, 0≤z≤0.5; and the magnetic heating element has a grain size of 40 nm to 500 nm, and powder of the magnetic heating element has a particle size of 100 nm to 30 μm. Accordingly, the adhesive including the magnetic heating element may improve adhesive performance and provide high-speed bonding.

Manganese-cobalt (Mn—Co) spinel oxide nanowire arrays are synthesized at low pressure and low temperature by a hydrothermal method. The method can include contacting a substrate with a solvent, such as water, that includes Mn04- and Co2 ions at a temperature from about 60° C. to about 120° C. The method preferably includes dissolving potassium permanganate (KMn04) in the solvent to yield the Mn04- ions. the substrate is The nanoarrays are useful for reducing a concentration of an impurity, such as a hydrocarbon, in a gas, such as an emission source. The resulting material with high surface area and high materials utilization efficiency can be directly used for environment and energy applications including emission control systems, air/water purifying systems and lithium-ion batteries.

A composite material comprising NiMoO.sub.4—CoMoO.sub.4 nanosheets can be an electrode in a hybrid supercapacitor. A hybrid supercapacitor having a cathode comprising the composite material exhibits a large operating window, high energy density and high cycling stability. The heterostructure material may be formed by a one-step chemical bath deposition process.

A spinel compound oxide particle includes metallic atoms, aluminum atoms, oxygen atoms, and molybdenum atoms, wherein the metallic atoms are selected from the group consisting of zinc atoms, cobalt atoms, and strontium atoms, and a crystallite size in a [111] plane is 100 nm or more. Included are a step (1) of firing a first mixture including a molybdenum compound and a metallic-atom-containing compound or a first mixture including a molybdenum compound, a metallic-atom-containing compound, and an aluminum compound to prepare an intermediate; and a step (2) of firing, at a temperature higher than a temperature selected in the step (1), a second mixture including the intermediate or a second mixture including the intermediate and an aluminum compound.

A method of obtaining a nickel zinc cobalt spinet ferrite in ceramic form that includes the following: obtaining a precipitate (1) of iron, nickel, zinc, and cobalt hydroxides by co-precipitation, rinsing the precipitate (2), drying and grinding (3) the rinsed precipitate in order to obtain a powder; forming (4) into a compact by pressing the powder, and sintering (5) the compact. The sintering (5) includes a progressive temperature rise of 2° C. to 4° C. per minute, from an ambient temperature to reach a maximum temperature comprised between 950° C. and 1.010° C., maintaining at the maximum temperature for forty-five minutes to three hours, a progressive fall in temperature of 2° C. to 4° C. per minute to reach ambient temperature. The foregoing and, in particular, the sintering, enable a material to be obtained that is particularly well-adapted to the manufacture of an antenna configured for frequencies less than one gigahertz.

The present invention generally relates to a process for synthesizing rare earth-doped cobalt-chromite (CoCr.sub.2-xR.sub.xO.sub.4) pigments for capacitive and resistive humidity sensor applications, the process includes of crushing individually metal nitrates and rare earth material (R) using a hydraulic press to form a powder of metal nitrates and rare earth nitrates; dissolving the powder of metal nitrates and rare earth material (R) with fuels in 30 milliliters of distilled water with constant stirring using a magnetic stirrer to form a green color solution; heating the green color solution at 425 degrees Celsius for half an hour to obtain a green powder; extracting and grinding the green powder in an agate mortar for 1 hour to form a fine green pigment; and annealing the fine green pigment in a muffle furnace for two hours at a temperature of 500-600 degrees to remove organic residue and obtain rare earth-doped cobalt-chromite (CoCr.sub.2-xR.sub.xO.sub.4) pigments.