By using a potassium ion secondary battery positive electrode active material comprising a potassium compound represented by general formula (1): K.sub.nMO.sub.m, wherein M is copper or iron, n is 0.5 to 3.5, and m is 1.5 to 2.5, provided is a potassium ion secondary battery positive electrode active material having higher theoretical discharge capacity and higher effective capacity than a potassium secondary battery using Prussian blue as a positive electrode active material.

A positive active material including: a core comprising a metal oxide, a non-metal oxide, or a combination thereof capable of intercalation and deintercalation of lithium ions or sodium ions; and a non-conductive carbonaceous film including oxygen on at least one portion of a surface of the core; a lithium battery including the positive active material; and a method of manufacturing the positive active material.

Provided is an active material for a fluoride-ion secondary battery, the active material containing a composite fluoride. The composite fluoride has a layered structure and is represented by a composition formula A.sub.mM.sub.nF.sub.x, where A is an alkali metal, M is a transition metal, 0<m2, 1n2, and 3x4. The alkali metal may be at least one kind selected from the group consisting of Na, K, Rb, and Cs. The transition metal may be a 3d transition metal.

The present invention relates to a bio-electrode for current measurement including silicon carbide (SiC) doped at least partially with nitrogen (N). The bio-electrode for current measurement according to an embodiment of the present invention is a bio-electrode for a current measurement which is contact with an object to be analyzed, which generates a current signal by an electrochemical reaction, and includes silicon carbide (SiC) doped at least partially with nitrogen (N). The electrode may be used in a high-sensitive bio-quantification kit, a high-sensitive bio-quantification device, and an immunoassay device.

The present invention relates to a bio-electrode for current measurement including silicon carbide (SiC) doped at least partially with nitrogen (N). The bio-electrode for current measurement according to an embodiment of the present invention is a bio-electrode for a current measurement which is contact with an object to be analyzed, which generates a current signal by an electrochemical reaction, and includes silicon carbide (SiC) doped at least partially with nitrogen (N). The electrode may be used in a high-sensitive bio-quantification kit, a high-sensitive bio-quantification device, and an immunoassay device.

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.

According to one embodiment, an active material is provided. This active material includes active material particles containing orthorhombic Na-containing niobium titanium composite oxide, and satisfies the following formula (1):
1A5/A0(1) where A5 is a mole content ratio of a Li mole content L5 to a total of a Ti mole content T5 and a Nb mole content N5, and A0 is a mole content ratio of a Li mole content L0 to a total of a Ti mole content T0 and a Nb mole content N0.

Producing Co.sub.xFe.sub.100-x, where x is an integer from 20 to 95, nanoparticles by: (a) providing a first aqueous hydroxide solution; (b) preparing a second aqueous solution containing iron ions and cobalt ions; and (c) depositing measured volumes of the second aqueous solution into the first aqueous solution whereby coprecipitation yields CoFe alloy nanoparticles, wherein step (c) occurs in an essentially oxygen-free environment. The nanoparticles are annealed at ambient temperatures to yield soft nanoparticles with targeted particle size, saturation magnetization and coercivity. The chemical composition, crystal structure and homogeneity are controlled at the atomic level. The CoFe magnetic nanoparticles have M.sub.s of 200-235 emu/g, (H.sub.c) coercivity of 18 to 36 O.sub.e and size range of 5-40 nm. The high magnetic moment CoFe nanoparticles can be employed in drug delivery, superior contrast agents for highly sensitive magnetic resonance imaging, magnetic immunoassay, magnetic labeling, waste water treatment, and magnetic separation.

Generating ferrate ex situ by activating persulfate with BOF steel slag fines and/or ferric iron. A persulfate solution flows therethrough or thereover the BOF steel slag within, for example, a filter, fluidized bed or continuously stirred tank reactor. The ex situ generation will produce a leachate that contains multiple reactive oxidant species (ROS) such as hydrogen peroxide (H.sub.2O.sub.2), superoxide (O2.), sulfate radicals, hydroxyl radicals (OH.) and uniquely ferrate species including Fe IV, V and VI. These ROS will destroy organic compounds, sterilize, and can oxidize inorganics and a wide range of targeted contaminants in distressed water (e.g., drinking water, process water, wastewater, industrial process streams/waters, municipal process streams/waters, landfill leachate, sewage/septic systems, bilge waters, drilling fluids, mine effluents). The use of BOF steel slag avoids the need for additional pH buffers and ferrate stabilizers and is an industrial byproduct comprised of recycled materials instead of a specialized reagent.

A composition for stabilizing iron compounds in an aqueous environment, includes a polycarboxylic acid or its salt(s), at least one monomeric or polymeric phosphonate including at least one phosphonic acid group, or its salt(s), at least one corrosion inhibitor including amino groups, and 1-15 weight-% of polycitric acid or a copolymer of citric acid with polyols or glycerol, calculated as an active ingredient from a total weight of constituents in the composition, as dry.