A method of preparing a catalyst for oxidative dehydrogenation that includes coprecipitation and injecting inert gas or air at a specific time point to reduce the ratio of an inactive α-Fe.sub.2O.sub.3 crystal structure, thereby improving the activity of the catalyst. Also provided is a method of performing oxidative dehydrogenation using the catalyst. When oxidative dehydrogenation of butene is performed using the catalyst, side reaction may be reduced, and selectivity for butadiene may be improved, providing butadiene with high productivity.

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.

Disclosed are embodiments of synthetic garnet materials for use in radiofrequency applications. In some embodiments, increased amounts of gadolinium can be added into specific sites in the crystal structure of the synthetic garnet by incorporating indium, a trivalent element. By including both indium and increased amounts of gadolinium, the dielectric constant can be improved. Thus, embodiments of the disclosed material can be advantageous in both above and below resonance applications, such as for isolators and circulators.

A multi-component mesocrystalline nanoparticle is provided. The multi-component mesocrystalline nanoparticle includes an iron oxide nanocluster; and metal oxide nanocrystals bound to a surface of the iron oxide.

Methods and apparatus for producing a magnetic nanoparticle suitable for additive manufacturing techniques includes providing a solution having a plurality of metallic precursors to produce magnetic nanoparticles, a coordinating solvent, and a chelating agent. The solution is mixed and heated to grow nanoparticles wherein magnetic nanoparticles are formed. The solution is then cooled and a magnetic field is applied to the solution wherein ferrite nanoparticles are at least partially separated by size.

The invention relates to active electrode materials and to methods for the manufacture of active electrode materials. Such materials are of interest as active electrode materials in lithium-ion or sodium-ion batteries. The invention provides an active electrode material expressed by the general formula M1.sub.aM2.sub.2-aM3.sub.bNb.sub.34-bO.sub.87-c-dQ.sub.d.

The present disclosure is directed to methods of Quantum Spin Engineering of spinel superparamagnetic ferrite nanoparticles (SMFNs) for MRI contrast agents and for magnetohyperthermia agents. Using the methods herein, the magnetic properties of the SMFNs can be controlled by changing the amount of 3d-transition element cations having unpaired electrons in the 3d orbital that occupy the octahedral sites of the spinel crystal form, to form mixed spinels, while anions in the spinels can be utilized to magnetically couple the cations utilizing intra-crystalline angles determined by ion sizes and crystal structure, and further tuning of other critical parameters is provided. The mixed spinels disclosed herein provide enhanced MRI contrast agents and improved magnetohyperthermia agents with lower toxicity and safety concerns, while the production methods disclosed herein have lower cost.

The present disclosure provides for compositions of magnetic nanoparticles and methods of making magnetic nano-particles with large magnetic diameters.

A method of rapid treatment of heavy metal sludge and preparation of ferrite magnets comprises following steps of: providing a sludge, the sludge at least having zinc metal and ferrous metal; adding an iron-containing substance to the sludge; pickling the sludge and the iron-containing substance with sulfuric acid to obtain a pickling solution with zinc ions and iron ions; neutralizing the pickling solution with sodium hydroxide to form hydroxide precipitates; and airing and heating the neutralized pickling solution by an ultrasonic-microwave method so that the hydroxide precipitates undergoing a ferrite magnet reaction, thereby obtaining ferrite magnets with a spathic structure.

Disclosed are embodiments of synthetic garnet materials for use in radiofrequency applications. In some embodiments, increased amounts of gadolinium can be added into specific sites in the crystal structure of the synthetic garnet by incorporating indium, a trivalent element. By including both indium and increased amounts of gadolinium, the dielectric constant can be improved. Thus, embodiments of the disclosed material can be advantageous in both above and below resonance applications, such as for isolators and circulators.