An electromagnetic wave absorbing sheet includes a metallic base and an electromagnetic wave absorption film formed on the metallic base. The electromagnetic wave absorption film contains MTC-substituted ε—Fe.sub.2O.sub.3, black titanium oxide, a conductive filler, and a resin. The MTC-substituted ε—Fe.sub.2O.sub.3 is a crystal belonging to the same space group as an ε—Fe.sub.2O.sub.3 crystal and containing Ti, Co, Fe, and at least one element selected from the group consisting of Ga, In, Al, and Rh. The proportion of the conductive filler to the electromagnetic wave absorption film is equal to or greater than 0.1% by volume and equal to or less than 10% by volume.

Magnetic powder includes: an epsilon-phase iron oxide-based compound selected from ε-Fe.sub.2O.sub.3 or a compound represented by Formula (1). The magnetic powder has an average particle diameter of 8 nm to 25 nm, a ratio of Hc to Hc′ of from 0.6 to 1.0, and Hc′ satisfying Expression (II). Hc′ represents a magnetic field at which a value of Expression (I) becomes zeroin a magnetic field-magnetization curve obtained by performing measurement at a maximum applied magnetic field of 359 kA/m, a temperature of 296 K, and a magnetic field sweeping speed of 1.994 kA/m/s. M represents magnetization and H represents applied magnetic field. Hc represents a magnetic field at which magnetization becomes zero in the magnetic field-magnetization curve. In Formula (1), A represents at least one metal element other than Fe, and a represents a number that satisfies a relationship of 0<a<2.

d.sup.2M/dH.sup.2  Expression (I)

119 kA/m<Hc′<2380 kA/m  Expression (II)

ε-A.sub.xFe.sub.2-xO.sub.3  (1)

A method for synchronous production of manganese tetraoxide and ferric oxide for a soft magnetic material by using marine polymetallic nodules includes: 1) crushing and grinding marine manganese nodules and baking to a constant weight; thoroughly mixing with a mixed flux and roasting in a muffle furnace; 2) carrying out solid-liquid separation, washing solid-phase precipitates with water, grinding the solid, adding sulfuric acid, controlling the temperature to be below 50° C., and vacuuming a reactor up; 3) adding a reducing agent to react at room temperature for 5-10 min, adding ammonia water to adjust the pH value to 5.5, and carrying out separation and filtering; 4) controlling the temperatures of manganese sulfate and ferric sulfate solutions to be below 50° C., and adding ammonium sulfide; and 5) washing with deionized water, and calcining at 800-900° C. for 1-3 s by a suspension low-temperature instantaneous firing system.

A method for synchronous production of manganese tetraoxide and ferric oxide for a soft magnetic material by using marine polymetallic nodules includes: 1) crushing and grinding marine manganese nodules and baking to a constant weight; thoroughly mixing with a mixed flux and roasting in a muffle furnace; 2) carrying out solid-liquid separation, washing solid-phase precipitates with water, grinding the solid, adding sulfuric acid, controlling the temperature to be below 50° C., and vacuuming a reactor up; 3) adding a reducing agent to react at room temperature for 5-10 min, adding ammonia water to adjust the pH value to 5.5, and carrying out separation and filtering; 4) controlling the temperatures of manganese sulfate and ferric sulfate solutions to be below 50° C., and adding ammonium sulfide; and 5) washing with deionized water, and calcining at 800-900° C. for 1-3 s by a suspension low-temperature instantaneous firing system.

The present invention provides a method for preparing iron oxide magnetic particles and iron oxide magnetic particles prepared thereby, wherein the method includes (a) synthesizing a complex by reacting iron and one or more compounds selected from the group consisting of an aliphatic hydrocarbonate having 4 to 25 carbon atoms and an amine compound, (b) synthesizing an iron oxide crystal nucleus by mixing the complex with a mixture of an unsaturated aliphatic hydrocarbon-based compound having 4 to 25 carbon atoms and an ether-based compound, and (c) forming a shell by mixing the iron oxide crystal nucleus and an MXn compound with a mixture of an unsaturated aliphatic hydrocarbon-based compound having 4 to 25 carbon atoms and an ether-based compound, wherein M is a heavy atom element, X is a halogen element, and n is an integer of 1 to 6.

The present invention provides a method for preparing iron oxide magnetic particles and iron oxide magnetic particles prepared thereby, wherein the method includes (a) synthesizing a complex by reacting iron and one or more compounds selected from the group consisting of an aliphatic hydrocarbonate having 4 to 25 carbon atoms and an amine compound, (b) synthesizing an iron oxide crystal nucleus by mixing the complex with a mixture of an unsaturated aliphatic hydrocarbon-based compound having 4 to 25 carbon atoms and an ether-based compound, and (c) forming a shell by mixing the iron oxide crystal nucleus and an MXn compound with a mixture of an unsaturated aliphatic hydrocarbon-based compound having 4 to 25 carbon atoms and an ether-based compound, wherein M is a heavy atom element, X is a halogen element, and n is an integer of 1 to 6.

A nanoparticle, which has a metal oxide core and a cerium shell is provided. The weight ratio of the cerium within the shell to the metal oxide in the core is at least 1%. Additionally a method for delivering a ligand into a cell with the nanoparticle is provided. Processes for making the nanoparticle which include: sonicating an aqueous composition containing Ceric Ammonium Nitrate and a prefabricated nano particle suspension; and (b) adding a polycationic polymer to the mixture (for NP surface functionalization), are also described.

A nanoparticle, which has a metal oxide core and a cerium shell is provided. The weight ratio of the cerium within the shell to the metal oxide in the core is at least 1%. Additionally a method for delivering a ligand into a cell with the nanoparticle is provided. Processes for making the nanoparticle which include: sonicating an aqueous composition containing Ceric Ammonium Nitrate and a prefabricated nano particle suspension; and (b) adding a polycationic polymer to the mixture (for NP surface functionalization), are also described.

A method of preparing iron oxide nanoparticles using an herbal mixture comprising Capparis spinosa, Cichorium intybus, Solanum nigrum, Cassia occidentalis, Terminalia arjuna, Achillea millefolium, and Tamarix gallica. The method produces crystalline γ-Fe.sub.2O.sub.3 nanoparticles which are superparamagnetic. The iron oxide nanoparticles are used in a method of killing or inhibiting the growth of a bacteria and/or fungus, particularly in the form of a biofilm. The nanoparticles are also used in a method of treating colon cancer.

A method of preparing iron oxide nanoparticles using an herbal mixture comprising Capparis spinosa, Cichorium intybus, Solanum nigrum, Cassia occidentalis, Terminalia arjuna, Achillea millefolium, and Tamarix gallica. The method produces crystalline γ-Fe.sub.2O.sub.3 nanoparticles which are superparamagnetic. The iron oxide nanoparticles are used in a method of killing or inhibiting the growth of a bacteria and/or fungus, particularly in the form of a biofilm. The nanoparticles are also used in a method of treating colon cancer.