A method is used to prepare silver nanoparticle cellulosic polymer composites. A cellulosic polymer, reducible silver ions in an amount of a weight ratio to the cellulosic polymer of 5:1 to 50:1, and an organic solvent are mixed. Each organic solvent has a boiling point at atmospheric pressure of 100 C. to 500 C. The Hansen parameter (.sub.T.sup.Polymer) of the cellulosic polymer is less than or equal to the Hansen parameter (.sub.T.sup.Solvent) of the organic solvent. The resulting premix solution is heated to at least 75 C., and a (d) nitrogenous base is added to provide a concentration of the nitrogenous base in an equimolar amount or in molar excess in relation to the amount of reducible silver ions, thereby forming a silver nanoparticle cellulosic polymer composite. After cooling, the silver nanoparticle cellulosic polymer composite is isolated and re-dispersed in an organic solvent to provide a non-aqueous silver-containing dispersion.

A non-aqueous silver-containing dispersion is prepared containing a silver nanoparticle composite comprising silver and a cellulosic polymers so that the silver nanoparticle composite is present at a weight ratio to a cellulosic polymers of at least 5:1 and up to and including 50:1. This dispersion also contains an organic solvent that has a boiling point, at atmospheric pressure, of 100 C. to 500 C. The Hansen parameter (.sub.T.sup.Polymer) of the cellulosic polymer is less than or equal to the Hansen parameter (.sub.T.sup.Solvent) of the organic solvent. A nitrogenous base having a pKa in acetonitrile of 15 to 25 at 25 C. is also present in an equimolar amount or molar excess in relation to the amount of silver.

A method is used to prepare silver nanoparticle cellulosic polymer composites. A cellulosic polymer, reducible silver ions in an amount of a weight ratio to the cellulosic polymer of 5:1 to 50:1, and an organic solvent are mixed. Each organic solvent has a boiling point at atmospheric pressure of 100 C. to 500 C. The Hansen parameter (.sub.T.sup.Polymer) of the cellulosic polymer is less than or equal to the Hansen parameter (.sub.T.sup.Solvent) of the organic solvent. The resulting premix solution is heated to at least 75 C., and a (d) nitrogenous base is added to provide a concentration of the nitrogenous base in an equimolar amount or in molar excess in relation to the amount of reducible silver ions, thereby forming a silver nanoparticle cellulosic polymer composite. After cooling, the silver nanoparticle cellulosic polymer composite is isolated and re-dispersed in an organic solvent to provide a non-aqueous silver-containing dispersion.

A non-aqueous silver precursor composition is composed of (a) one or more cellulosic polymers; (b) reducible silver ions that are present at a weight ratio to the one or more cellulosic polymers of 5:1 to 50:1; (c) an organic solvent that has a boiling point at atmospheric pressure of at least 100 C. and up to but less than 500 C.; and (d) a nitrogenous base having a pKa in acetonitrile of at least 15 and up to and including 25 at 25 C. The Hansen parameter (.sub.T.sup.Polymer) of each cellulosic polymer is less than or equal to the Hansen parameter (.sub.T.sup.Solvent) each organic solvent. In addition, the (d) nitrogenous base is present in an equimolar amount or molar excess in relation to the amount of (b) reducible silver ions.

A method of forming a near field transducer (NFT) layer, the method including depositing a film of a primary element, the film having a film thickness and a film expanse; and implanting at least one secondary element into the primary element, wherein the NFT layer includes the film of the primary element doped with the at least one secondary element.

A method of forming a near field transducer (NFT) layer, the method including depositing a film of a primary element, the film having a film thickness and a film expanse; and implanting at least one secondary element into the primary element, wherein the NFT layer includes the film of the primary element doped with the at least one secondary element.

A thermoelectric conversion material is represented by a composition formula Ag.sub.2S.sub.(1-x)Se.sub.x, where x has a value of greater than 0.01 and smaller than 0.6.

A thermoelectric conversion material is represented by a composition formula Ag.sub.2S.sub.(1-x)Se.sub.x, where x has a value of greater than 0.01 and smaller than 0.6.

A method for producing a carbon composite material to reduce costs; and a carbon composite material includes a dealloying step of immersing a carbon-containing material composed of a compound, alloy or non-equilibrium alloy containing carbon in a metal bath, the metal bath having a solidification point lower than a melting point of the carbon-containing material, the metal bath being controlled to a lower temperature than a minimum value of a liquidus temperature within a compositional fluctuation range extending from the carbon-containing material to carbon by decreasing other non-carbon main components, to thereby selectively elute the other non-carbon main components into the metal bath to form a carbon member having microvoids; and a cooling step performed with the microvoids of the carbon member including a component of the metal bath to solidify the component. The carbon composite material combining carbon with the metal bath component that has solidified is thereby obtained.

The present invention relates to a method of producing metal nanoparticles and metal sulfide nanoparticles using a recombinant microorganism co-expressing metallothionein and phytochelatin synthase, which are heavy metal-adsorbing proteins, and to the use of metal nanoparticles and metal sulfide nanoparticles synthesized by the method. The present invention provides a method for synthesizing metal nanoparticles which have been difficult to synthesize by conventional biological methods. The present invention makes it possible to synthesize metal nanoparticles in an environmentally friendly and cost-effective manner, and also makes it possible to synthesize metal sulfide nanoparticles. In addition, even metal nanoparticles which could have been produced by conventional chemical or biological methods are produced in a significantly increased yield by use of the method of the present invention.