455 results about "Micrometer scale" patented technology

Self-organized, or self-assembled, nanowires of a first composition may be used as an etching mask for fabrication of nanowires of a second composition. The method for forming such nanowires comprises: (a) providing an etchable layer of the second composition and having a buried insulating layer beneath a major surface thereof; (b) growing self-assembled nanowires on the surface of the etchable layer; and (c) etching the etchable layer anisotropically down to the insulating layer, using the self-assembled nanowires as a mask. The self-assembled nanowires may be removed or left. In either event, nanowires of the second composition are formed. The method enables the formation of one-dimensional crystalline nanowires with widths and heights at the nanometer scale, and lengths at the micrometer scale, which are aligned along certain crystallographic directions with high crystal quality. Further, the method of the present invention avoids traditional lithography methods, minimizes environmental toxic chemicals usage, simplifies the manufacturing processes, and allows the formation of high-quality one-dimensional nanowires over large areas.

The invention relates to a method for obtaining a surface of a titanium-based metal implant intended to be inserted into bone tissue, comprising: (a) projecting particles of aluminium oxide under pressure on the external area of the implant; (b) chemically treating the sandblasted external area of the implant with an acid composition comprising sulfuric acid and hydrofluoric acid; and (c) thermally treating the sandblasted external area of the implant by heating at a temperature of 200-450° C. for 15-120 min. The invention likewise defines a metal implant having said surface. The surface thus obtained has good micrometer-scale roughness with a suitable morphology, as well as a composition which is virtually free of impurities and a thickness which is approximately three times the thickness of conventional surfaces, which characteristics provide it with very good osseointegration properties.

The invention which belongs to the technical field of new materials relates to a synthetic method of ZIFs, and concretely discloses a method for synthesizing nanometer/micrometer scale ZIFs based on imidazole and its derivatives at room temperature in a concise, efficient and green manner. The method comprises the following steps: dissolving a single imidazole ligand or a mixture of two imidazole ligands in water or an organic liquid to form a solution, adding an alkaline substance to adjust the pH value of the solution, adding a metal salt to form a reaction system, and reacting to obtain the nanometer or micrometer scale ZIFs. The method which allows routine reactants to be utilized and the alkaline substance to be added to adjust the pH value of the system has the advantages of ligand application amount reduction, controllable product size, and high purity of the nanometer/micrometer scale ZIFs. The synthetic method has the characteristics of cheap and easily available raw materials and solvent, and no pollution, and has important meanings to the production and the application of the ZIFs.

This invention discloses a method for preparing multi-level porous beta-zeolite. The method comprises: soaking monolithic silica gel column in sucrose solution, drying, polymerizing, carbonizing to obtain C-Si composite, wetting the C-Si composite with a mixed solution of Al source, inorganic alkali, organic amine and water, crystallizing, and recovering the product. In this method, carbon material can effectively protect the porous structure of monolithic silica gel column from damage during crystallization process. The obtained beta-zeolite has multi-level pores, including micrometer-scale macropores, mesopores and micropores. The macropores can shorten the diffusion distances of reactive molecules, reduce the pressure decrease of the equipment, raise the unit processing capacity of the equipment, and make the adjustment and control of the product selectivity easier. The mesopores can provide large inner specific surface area, which is meaningful to the catalytic reaction of macromolecules.

The invention relates to the preparation of a porous surface, and discloses a micro-nano composite porous copper surface structure and a preparation method and a preparation device thereof. The preparation method for the micro-nano composite porous copper surface structure is a method for electro-deposition by a hydrogen template method, takes red copper as an anode and a cathode substrate, and includes: performing electro-deposition by taking red copper as an anode and a cathode substrate, and the mixture consisting of the H2SO4 and CuSO4 aqueous solution and additives as the electro-deposition solution to obtain an electro-deposition sample, soaking the electro-deposition sample with deionized water and ethanol and then drying to obtain the micro-nano composite porous copper surface structure; and thermally treating the obtained micro-nano composite porous copper surface structure to enhance the mechanical performance of the micro-nano composite porous copper surface structure. The device for preparing the micro-nano composite porous copper surface structure comprises an electro-deposition tank, an electro-deposition solution, a direct current power supply, a cathode substrate and an anode. The preparation method is simple to operate, and low in cost, and the micro-nano composite porous copper surface structure is controllable; and by the method, a micro-nano composite structure formed by superposing a micrometer scale aperture structure and a wall nano dendrites structure can be prepared, and the aperture of the structure is gradually increased and the structure is uniform.

Self-assembled nanowires are provided, comprising nanowires of a first crystalline composition formed on a substrate of a second crystalline composition. The two crystalline materials are characterized by an asymmetric lattice mismatch, in which in the interfacial plane between the two materials, the first material has a close lattice match (in any direction) with the second material and has a large lattice mismatch in all other major crystallographic directions with the second material. This allows the unrestricted growth of the epitaxial crystal in the first direction, but limits the width in the other. The nanowires are grown by first selecting the appropriate combination of materials that fulfill the foregoing criteria. The surface of the substrate on which the nanowires are to be formed must be cleaned in order (1) to ensure that the surface has an atomically flat, regular atomic structure on terraces and regular steps and (2) to remove impurities. Finally, epitaxial deposition of the first crystalline material on the cleaned surface is performed, thereby forming the self-assembled nanowires. Thus, one-dimensional epitaxial crystals are obtained with widths and heights at the nanometer scale, and lengths at the micrometer scale, which are aligned along certain crystallographic directions with high crystal quality.

The invention discloses a method and a system that are used for measuring the Seebeck coefficient of a quasi-one-dimensional nano material; two line transition electrodes with micrometer-scaled cross sections are respectively contacted with two centimeter-scaled block metal electrodes, a nano probe system is utilized for leading a single rod of the quasi-one-dimensional nano material to be detected to be connected with the two transition electrodes, temperature difference between the two block metal electrodes is altered, and the temperature difference and corresponding potential difference between the two electrodes are simultaneously measured, thus obtaining the Seebeck coefficient of the quasi-one-dimensional nano material. The corresponding testing system comprises three parts of an experimental platform, a temperature altering device and a data collecting and processing device. The method and the system solve the problem of the contact transition between the centimeter-scaled electrodes and the nano sample to be detected through the micrometer-scaled transition electrodes, utilize the nano probe system for installing the nano material, and lead the nano material not to be randomly dispersed at two sides of the electrodes, thus improving experimental success rate, controllability and reliability; and the provided measuring system has the advantages of simple structure, low cost and easy popularization and the like.

Methods and systems of predicting fatigue life in aluminum castings that combines extreme values of both casting flaws and microstructures with multiscale life models. The multiscale life models account for differing fatigue crack initiation based on the size scale of the defect and microstructure features, including provisions for generally millimeter scale casting flaws, generally micrometer scale second phase particles by cracking or debonding, or submicrometer scale dislocation interactions with precipitates which form persistent slip bands. In the presence of casting flaws, the fatigue initiation life is negligible and the total fatigue life is spent in propagation of a fatigue crack from such flaws. In the absence of casting flaws, however, the total fatigue life is spent in both crack initiation and propagation, except for the case where fatigue cracks initiate from large second phase particles in a coarse microstructure. The extreme values of casting flaws, second phase particles, mean free path through an aluminum matrix or grain sizes are obtained from extreme value statistics when two or three dimensional sizes of casting flaws and microstructure features are provided by either direct measurement or analytical prediction. The upper bound flaw or microstructure feature size is calculated by extreme value statistics.

The invention relates to nanomaterials and assemblies including, a micrometer-scale spherical aggregate comprising: a plurality of one-dimensional nanostructures comprising titanium and oxygen, wherein the one-dimensional nanostructures radiate from a hollow central core thereby forming a spherical aggregate.

A thermally stabilized, high speed, micrometer-scale silicon electro-optic modulator is provided. Methods for maintaining desired temperatures in electro-optic modulators are also provided. The methods can be used to maintain high quality modulation in the presence of thermal variations from the surroundings. Direct current injection into the thermally stabilized electro-optic modulator is used to maintain the modulation performance of the modulator. The direct injected current changes the local temperature of the thermally stabilized electro-optic modulator to maintain its operation over a wide temperature range.

The invention relates to a coaxial focusing electro stream printing method, belongs to the technical field of advanced manufacture and relates to a coaxial focusing electro stream printing method. According to the method, in the coaxial focusing electro stream printing process, two kinds of liquid are contained in a coaxial focusing electro stream printing nozzle, one kind of the liquid is a required forming material called inner function liquid, and the other kind of the liquid is an auxiliary material called outer liquid; the outer liquid and the inner function liquid are not dissolved mutually, and the viscosity of the outer liquid is larger than that of the inner function liquid. The coaxial focusing electro stream printing nozzle forms coaxial focusing jet flow with the two layers of liquid during printing and prints a bi-layer structure on a substrate; and finally, an outer printing material is removed to obtain an inner function structure. The method has the characteristics of being high in printing resolution, material adaptability and microenvironment disturbance resistance and is capable of achieving high-resolution patterned printing through a spray needle of micrometer scales at normal temperatures and pressures.

Microstructured nuclear fuel adapted for nuclear power system use includes fissile material structures of micrometer-scale dimension dispersed in a matrix material. In one method of production, fissile material particles are processed in a chemical vapor deposition (CVD) fluidized-bed reactor including a gas inlet for providing controlled gas flow into a particle coating chamber, a lower bed hot zone region to contain powder, and an upper bed region to enable powder expansion. At least one pneumatic or electric vibrator is operationally coupled to the particle coating chamber for causing vibration of the particle coater to promote uniform powder coating within the particle coater during fuel processing. An exhaust associated with the particle coating chamber and can provide a port for placement and removal of particles and powder. During use of the fuel in a nuclear power reactor, fission products escape from the fissile material structures and come to rest in the matrix material. After a period of use in a nuclear power reactor and subsequent cooling, separation of the fissile material from the matrix containing the embedded fission products will provide an efficient partitioning of the bulk of the fissile material from the fission products. The fissile material can be reused by incorporating it into new microstructured fuel. The fission products and matrix material can be incorporated into a waste form for disposal or processed to separate valuable components from the fission products mixture.

The present invention provides a porous medium with increased hydrophobicity and a method of manufacturing the same, in which a micro-nano dual structure is provided by forming nanoprotrusions with a high aspect ratio by performing plasma etching on the surface of a porous medium with a micrometer-scale surface roughness and a hydrophobic thin film is deposited on the surface of the micro-nano dual structure, thus significantly increasing hydrophobicity. When this highly hydrophobic porous medium is used as a gas diffusion layer of a fuel cell, it is possible to efficiently discharge water produced during electrochemical reaction of the fuel cell, thus preventing flooding in the fuel cell. Moreover, it is possible to sufficiently supply reactant gases such as hydrogen and air (oxygen) to a membrane electrode assembly (MEA), thus improving the performance of the fuel cell.

Disclosed is a fuel cell with enhanced mass transfer characteristics in which a highly hydrophobic porous medium, which is prepared by forming a micro-nano dual structure in which nanometer-scale protrusions with a high aspect ratio are formed on the surface of a porous medium with a micrometer-scale roughness by plasma etching and then by depositing a hydrophobic thin film thereon, is used as a gas diffusion layer, thereby increasing hydrophobicity due to the micro-nano dual structure and the hydrophobic thin film. When this highly hydrophobic porous medium is used as a gas diffusion layer for a fuel cell, it is possible to reduce water flooding by efficiently discharging water produced by an electrochemical reaction of the fuel cell and to improve the performance of the fuel cell by facilitating the supply of reactant gases such as hydrogen and air (oxygen) to a membrane-electrode assembly (MEA).