The method of synthesizing magnetite/maghemite core/shell nanoparticles is a modified co-precipitation method for producing iron oxide (Fe.sub.3O.sub.4/-Fe.sub.2O.sub.3) nanoparticles that allows for production of the Fe.sub.3O.sub.4/-Fe.sub.2O.sub.3 core/shell nanoparticles with a desired shell thickness ranging between about 1 nm to 5 nm for biomedical and data storage applications. Aqueous solutions of ferric and ferrous salts are mixed at room temperature and pH of the mixture is raised to 10. The mixture is then heated at 80 C. for different lengths of time at atmospheric pressure to adjust particle size, and the precipitate is dried at 120 C. in vacuum. Oxidation in an oxygen atmosphere for different lengths of time is used to adjust the thickness of the -Fe.sub.2O.sub.3 shell.

A process of growth in the thickness of at least one facet of a colloidal inorganic sheet, by sheet is meant a structure having at least one dimension, the thickness, of nanometric size and lateral dimensions great compared to the thickness, typically more than 5 times the thickness. The process allows the deposition of at least one monolayer of atoms on at least one inorganic colloidal sheet, this monolayer being constituted of atoms of the type of those contained or not in the sheet. Homostructured and heterostructured materials resulting from such process as well as the applications of the materials are also described. By homostructured is meant a material of homogeneous composition in the thickness and by heterostructured is meant a material of heterogeneous composition in the thickness.

A multi-walled titanium-based nanotube array containing metal or non-metal dopants is formed, in which the dopants are in the form of ions, compounds, clusters and particles located on at least one of a surface, inter-wall space and core of the nanotube. The structure can include multiple dopants, in the form of metal or non-metal ions, compounds, clusters or particles. The dopants can be located on one or more of on the surface of the nanotube, the inter-wall space (interlayer) of the nanotube and the core of the nanotube. The nanotubes may be formed by providing a titanium precursor, converting the titanium precursor into titanium-based layered materials to form titanium-based nanosheets, and transforming the titanium-based nanosheets to multi-walled titanium-based nanotubes.

Various methods and systems are provided for cryogenic heat transfer by nanoporous surfaces. In one embodiment, among others, a system includes a cryogenic fluid in a flow path of the system; and a system component in the flow path that includes a nanoporous surface layer in contact with the cryogenic fluid. In another embodiment, a method includes providing a cryogenic fluid; and initiating chilldown of a cryogenic system by directing the cryogenic fluid across a nanoporous surface layer disposed on a surface of a system component.

A system for the physical manipulation of free magnetic rotors in a circulatory system using a remotely placed magnetic field-generating stator is provided. In one embodiment, the invention relates to the control of magnetic particles in a fluid medium using permanent magnet-based or electromagnetic field-generating stator sources. Such a system can be useful for increasing the diffusion of therapeutic agents in a fluid medium, such as a human circulatory system, which can result in substantial clearance of fluid obstructions, such as vascular occlusions, in a circulatory system resulting in increased blood flow. Examples of vascular occlusions targeted by the system include, but are not limited to, atherosclerotic plaques, including fibrous caps, fatty buildup, coronary occlusions, arterial stenosis, restenosis, vein thrombi, arterial thrombi, cerebral thrombi, embolisms, hemorrhages, other blood clots, and very small vessels.

Disclosed herein are iron oxide nanoparticles prepared through high-temperature thermal decomposition of an Fe.sup.3+ precursor and an M.sup.+ or M.sup.2+ (M=Li, Na, K, Mg, and Ca) precursor in an oxygen atmosphere. The iron oxide nanoparticles are nanoparticles, in which an alkali metal or alkali earth metal is doped into an Fe vacancy site of -Fe.sub.2O.sub.3, and generate explosive heat even in a biocompatible low AC magnetic field. Through both in vitro and in vivo tests, it was proven that cancer cells could be killed by performing low-frequency hyperthermia using the iron oxide nanoparticles set forth above.

Vacuum deposited thin films of material are used to create an interface that non-preferentially interacts with different domains of an underlying block copolymer film. The non-preferential interface prevents formation of a wetting layer and influences the orientation of domains in the block copolymer. The purpose of the deposited polymer is to produce nano structured features in a block copolymer film that can serve as lithographic patterns.

Some embodiments provide a system for external manipulation of magnetic nanoparticles in vasculature using a remotely placed magnetic field-generating stator. In one aspect, the systems and methods relate to the control of magnetic nanoparticles in a fluid medium using permanent magnet-based or electromagnetic field-generating stator sources. Such a system can be useful for increasing the diffusion of therapeutic agents in a fluid medium, such as a human circulatory system, which can result in substantial clearance of fluid obstructions, such as vascular occlusions, in a circulatory system resulting in increased blood flow.

A composite powder in which highly dispersed metal oxide nanoparticle precursors are supported on carbon is rapidly heated under nitrogen atmosphere, crystallization of metal oxide is allowed to progress, and highly dispersed metal oxide nanoparticles are supported by carbon. The metal oxide nanoparticle precursors and carbon nanoparticles supporting said precursors are prepared by a mechanochemical reaction that applies sheer stress and centrifugal force to a reactant in a rotating reactor. The rapid heating treatment in said nitrogen atmosphere is desirably heating to 400 C. to 1000 C. By further crushing the heated composite, its aggregation is eliminated and the dispersity of metal oxide nanoparticles is made more uniform. Examples of a metal oxide that can be used are manganese oxide, lithium iron phosphate, and lithium titanate. Carbons that can be used are carbon nanofiber and Ketjen Black.

A method of producing electronic plasmons by applying a bias to a molecular tunnel junction to excite plasmons, in which the molecular tunnel junction contains a top metallic electrode formed of a eutectic metal alloy and a metal oxide, a bottom metallic electrode formed of a transition metal, and a self-assembled monolayer formed of a plurality of organic molecules disposed between the top metallic electrode and the bottom metallic electrode. Also disclosed are a molecular tunnel junction for producing electronic plasmons and a method for preparing such a molecular tunnel junction.