A method of preparing iron oxide nanoparticles using an herbal mixture comprising Capparis spinosa, Cichorium intybus, Solanum nigrum, Cassia occidentalis, Terminalia arjuna, Achillea millefolium, and Tamarix gallica. The method produces crystalline γ-Fe.sub.2O.sub.3 nanoparticles which are superparamagnetic. The iron oxide nanoparticles are used in a method of killing or inhibiting the growth of a bacteria and/or fungus, particularly in the form of a biofilm. The nanoparticles are also used in a method of treating colon cancer.

A positive electrode active material is constituted by lithium transition metal-containing composite oxide particles having a layered rock salt type crystal structure and are composed of secondary particles each formed of an aggregation of primary particles. The secondary particles have a d50 of 3.0 to 7.0 μm, a BET specific surface area of 1.8 to 5.5 m.sup.2/g, a pore peak diameter of 0.01 to 0.30 μm, and a log differential pore volume [dV/d(log D)] of 0.2 to 0.6 ml/g within a range of the pore peak diameter. In each of a plurality of primary particles having a primary particle size of 0.1 to 1.0 μm, a coefficient of variation of the concentration of an additive element M is 1.5 or less.

A positive electrode active material for a non-aqueous electrolyte secondary battery, according to an example of this embodiment, includes a lithium transition metal composite oxide which has a layered structure and contains at least Ni, Al, and Ca. The lithium transition metal composite oxide has a Ni content of 85-95 mol %, an Al content of at most 8 mol %, and a Ca content of at most 2 mol % with respect to the total amount of metal elements other than Li. In addition, the proportion of metal elements other than Li present in a Li layer is 0.6-2.0 mol % with respect to the total amount of metal elements other than Li contained in the composite oxide.

An alumina grain has a single-crystal structure and has an approximate regular octahedral stereoscopic morphology. Eight sides of the alumina grain belong to the {111} family of crystal planes of γ-state alumina, and the grain size is 5-100 μm. The alumina grain is unique in crystal plane exposure and distribution, simple and feasible in preparation, and low in cost, and has higher operability, and thus has good application prospect in the field of catalysis and adsorption.

A method of making an alumina including providing an alumina slurry, aging the slurry, adding a tricarboxylic acid to the aged alumina slurry, further aging the slurry, and spray drying, the method being characterized by the addition of a dicarboxylic acid either at the same time as the tricarboxylic acid, or after the second aging and before the spray drying. The resulting alumina is dispersible at a pH greater than 9.5 above 95% and has a viscosity below 0.4 Pa.Math.S for 10 wt % sols.

A positive electrode active material for a secondary battery includes a first positive electrode active material and a second positive electrode active material, wherein an average particle diameter (D.sub.50) of the first positive electrode active material is twice or more than an average particle diameter (D.sub.50) of the second positive electrode active material, and the second positive electrode active material has a crystallite size of 200 nm or more.

A nickel-based hydroxide powder is provided which has an average crystallite size, as determined by Scherrer fitting of the (00I) reflections of an XRD powder diffraction pattern of the nickel-based hydroxide powder, of at most 10 nm, together with a process for producing nickel-based hydroxide powders. The nickel-based hydroxide powders find utility as precursors for the formation of lithium transition metal oxide active electrode materials.

The positive electrode active material is capable of reducing positive electrode resistance, exhibiting better output characteristics, and having high mechanical strength when the positive electrode active material is used in a lithium ion secondary battery. Secondary particles have a d50 of 3.0 to 7.0 μm, a BET specific surface area of 2.0 to 5.0 m.sup.2/g, a tap density of 1.0 to 2.0 g/cm.sup.3, and an oil absorption amount of 30 to 60 ml/100 g. In each of a plurality of primary particles having a primary particle size of 0.1 to 1.0 μm, a coefficient of variation of the concentration of an additive element M is 1.5 or less. The volume of a linking section between the primary particles per primary particle, obtained from the total volume of the linking section and the number of primary particles constituting the secondary particles, is 5×10.sup.5 to 9×10.sup.7 nm.sup.3.

A positive electrode active material for obtaining a lithium ion secondary battery, wherein capacity, electron conductivity, durability, and heat stability at the time of overcharge are improved, durability and heat stability being achieved at a high level, and including: a lithium nickel manganese composite oxide composed of secondary particles, in which a plurality of primary particles are flocculated, wherein the composite oxide is represented by a general formula (1): Li.sub.dNi.sub.1-a-b-cMn.sub.aM.sub.bTi.sub.cO.sub.2 (wherein, M is at least one kind of element selected from Co, W, Mo, V, Mg, Ca, Al, Cr, Zr and Ta, 0.05≤a≤0.60, 0≤b≤0.60, 0.02≤c≤0.08, 0.95≤d≤1.20), at least a part of titanium in the composite oxide is solid-solved in the primary particles, and, a lithium titanium compound exists on a surface of the positive electrode active material for the lithium ion secondary battery.

The present invention is characterized by including an aromatic vinyl-based copolymer, glass fiber, and zinc oxide, wherein the zinc oxide has an average particle size (D50) of about 0.5 to 3 μm as measured by a particle size analyzer, and a size ratio (B/A) of peak B, spanning the range of 450 to 600 nm, to peak A, spanning the range of 370 to 390 nm, of about 0.01 to 1.0 when measuring photoluminescence. The thermoplastic resin composition exhibits excellent rigidity, antibacterial properties, weather resistance, external appearance and the like.