A silver powder, including: an organic substance on a surface of the silver powder, the organic substance containing at least one carboxyl group and at least one hydroxyl group in one molecule of the organic substance, wherein a BET specific surface area of the silver powder is 0.1 m.sup.2/g or more but 2.0 m.sup.2/g or less, and wherein a cumulative 50% point of particle diameter (D.sub.50) of the silver powder in a volume-based particle size distribution of the silver powder as measured by a laser diffraction particle size distribution analysis is 0.1 μm or more but 6.0 μm or less, and a ratio of [(D.sub.90−D.sub.10)/D.sub.5o] is 3.0 or less, where D.sub.50 is the cumulative 50% point of particle diameter, D.sub.90 is a cumulative 90% point of particle diameter of the silver powder, and D.sub.10 is a cumulative 10% point of particle diameter of the silver powder.

A silver powder, including: an organic substance on a surface of the silver powder, the organic substance containing at least one carboxyl group and at least one hydroxyl group in one molecule of the organic substance, wherein a ratio of (Casson yield value/BET specific surface area) is 500 or less, where the Casson yield value is a Casson yield value of a conductive paste and the BET specific surface area is a BET specific surface area of the silver powder, where the conductive paste has a composition in which the silver powder is 86% by mass, a glass fit is 1% by mass, ethyl cellulose is 0.6% by mass, texanol is 10.5% by mass, and zinc oxide is 1.9% by mass, and the conductive paste is prepared by kneading the composition with a planetary centrifugal stirrer and bubble remover and dispersing with a triple roll mill.

The present invention provides an alloy fine particle including palladium and ruthenium, the alloy fine particle including at least one first phase in which the palladium is more abundant than the ruthenium and at least one second phase in which the ruthenium is more abundant than the palladium, the at least one first phase and the at least one second phase being separated by a phase boundary, the palladium and the ruthenium being distributed in the phase boundary in such a manner that the molar ratio of the palladium and the ruthenium continually changes, a plurality of crystalline structures being present together in the phase boundary.

A concentrated dispersion of nanometric silver particles, and a method of producing the dispersion, the dispersion including a first solvent; a plurality of nanometric silver particles, in which a majority are single-crystal silver particles, the plurality of nanometric silver particles having an average secondary particle size (d.sub.50) within a range of 30 to 300 nanometers, the particles disposed within the solvent; and at least one dispersant; wherein a concentration of the silver particles within the dispersion is within a range of 30% to 75%, by weight, and wherein a concentration of the dispersant is within a range of 0.2% to 30% of the concentration of the silver particles, by weight.

A method of reducing silver(I) salts to silver nanoparticles employing a carbohydrate reductant in the presence of an inorganic base, a surfactant and optionally a polymer. The method is performed in an aqueous solution at a temperature up to 60° C. and for a duration of up to 40 minutes.

Provided are: metallic copper particles exhibiting excellent low-temperature sintering properties at temperatures equal to or lower than 300° C.; and a production method therefor. In these metallic copper particles, metallic copper fine particles are adhered to the surfaces of large-diameter metallic copper particles. With regard to the metallic copper particles to be produced, copper oxide and hypophosphoric acid and/or a salt thereof are mixed and reduced, preferably in the presence of 1-500 mass % of gelatin and/or collagen peptide. The reduction reaction temperature is preferably in the range of 20-100° C. The produced metallic copper particles have a volume resistivity value when heated to a temperature of 300° C. under a nitrogen atmosphere of 1×10-2 Ω.Math.cm or less.

Described herein is a method of making a reduced metal nanoparticle, the method including mixing a reactive reducing agent with a metal salt in a solution at a temperature of 4-100° C., and forming the reduced metal nanoparticles in the solution. Also described is a kit including a reactive reducing agent that is sensitive to ßgalactosidase, a metal salt, and optionally a modifying agent/functionalizing agent for reduced metal nanoparticles. A 3,4-cyclohexeneoesculetin-B-D-galacto pyranoside (SGNP) gold nano article and its use for measuring ßgalactosidase enzyme activity, comprising by detecting a structural change in the SGNPs caused by the ßgalactosidase are described. Further described are a point of care device, a chip, a biosensor, a laboratory animal, a gene delivery agent, a drug delivery agent, a diagnostic agent, or a disease targeting agent including SGNPs.

To provide a metal-based structure or nanoparticles whose homogeneity is not deteriorated and whose sticking formation is easy, and a production method thereof with a high safety. A metal-based structure comprises a hydrogen compound, cluster, or an aggregate thereof, represented by the general formula: M.sub.mH. The M is a metal-based atom. The m is an integer of 3 or more and 300 or less. H is a hydrogen atom.

The present disclosure relates to a method of synthesizing metal nanoparticles, where the method includes mixing a metal precursor with a stabilizing ligand in a first zone of a first fluidic device to form a first mixture and mixing the first mixture with a reductant in a second zone of the first fluidic device to form a second mixture, such that the metal nanoparticles form in the second zone.

A system for preparing nanoscale zero-valent iron by reverse filtration in a non-open inert atmosphere is provided including an inert gas bottle, a gas monitoring and buffering device, a main reaction device configured as a three-necked flask, a condensing device including a condenser tube and a cold source, a waste liquid collecting device configured as a waste liquid collecting bottle, a liquid sealing device including a second liquid sealing bottle connected with the waste liquid collecting bottle through a first connecting-pipe, and an extraction pressure adjusting device including a third triple valve and a vacuum pump, all of which are connected by pipelines in sequence. Three necks of the three-necked flask are respectively provided with a first triple valve, a single-hole rubber plug pierced with a liquid-taking pipe, and a second triple valve. The second liquid sealing bottle is connected with the third triple valve.