The invention provides a core-shell particle which can provide, by being calcinated, epsilon type iron oxide-based compound particles that have a small coefficient of variation of primary particle diameter and show excellent SNR and running durability when employed in a magnetic recording medium as well as applications thereof. The core-shell particle includes: a core including at least one iron oxide selected from Fe.sub.2O.sub.3 or Fe.sub.3O.sub.4, or iron oxyhydroxide; and a shell that coats the core, the shell including a polycondensate of a metal alkoxide and a metal element other than iron, as well as applications thereof.

Doped titanium niobate is provided, which has a chemical structure of Ti.sub.(1-x)M1.sub.xNb.sub.2O.sub.(7-z)S.sub.z, wherein M1 is Li, Mg, or a combination thereof; 0?x?0.15; and 0.0025?z?0.075. A battery is provided, which includes a negative electrode; a positive electrode; and an electrolyte disposed between the negative electrode and the positive electrode, wherein the negative electrode includes the doped titanium niobate.

A carrier core material formed with ferrite particles, the skewness Rsk of the particle is equal to or more than 0.40 but equal to or less than 0.20, and the kurtosis Rku of the particle is equal to or more than 3.20 but equal to or less than 3.50. Here, the maximum height Rz of the particle is equal to or more than 2.20 m but equal to or less than 3.50 m. Moreover, the ferrite particle contains at least either of Mn and Mg elements. In this way, cracking or chipping in a concave-convex portion of a particle surface is unlikely to occur, and moreover, the amount of coating resin used can be reduced without properties such as electrical resistance being lowered.

Provided is a material that can be used as a potassium secondary battery positive electrode active material (particularly a potassium ion secondary battery positive electrode active material), other than Prussian blue, by using a potassium compound and a potassium ion secondary battery positive electrode active material comprising the potassium compound, the potassium compound being represented by general formula (1):

K.sub.nA.sub.kBO.sub.m,

wherein A is a positive divalent element in groups 7 to 11 of the periodic table; B is positive tetravalent silicon, germanium, titanium or manganese, excluding a case in which A is manganese and B is titanium, and a case in which A is cobalt and B is silicon; n is 1.5 to 2.5; and m is 3.5 to 4.5.

A method for manufacturing a magnetic powder includes changing a coercive force of a magnetic powder by irradiation with a radiation.

There is provided a magnetic substance containing substituted -iron oxide particles applicable as a magnetic toner of one-component development system, and a technique related thereto, which is the magnetic substance containing substituted -iron oxide particles in which a part of -iron oxide is substituted with a metal element other than iron, and satisfying at least one of the following conditions: (Condition 1) A molar extinction coefficient of a magnetic substance dispersion liquid at a wavelength of 450 nm is less than 770 dm.sup.3 mol.sup.1 cm.sup.1. (Condition 2) A molar extinction coefficient of the magnetic substance dispersion liquid at a wavelength of 500 nm is less than 430 dm.sup.3 mol.sup.1 cm.sup.1.

An oxygen carrier (OC) for use in Chemical Looping technology with Oxygen Uncoupling (CLOU) for the combustion of carbonaceous fuels, in which commercial grade metal oxides selected from the group consisting of Cu, Mn, and Co oxides and mixtures thereof constitute a primary oxygen carrier component. The oxygen carrier contains, at least, a secondary oxygen carrier component which is comprised by low-value industrial materials which already contain metal oxides selected from the group consisting of Cu, Mn, Co, Fe, Ni oxides or mixtures thereof. The secondary oxygen carrier component has a minimum oxygen carrying capacity of 1 g of O.sub.2 per 100 g material in chemical looping reactions. Methods for the manufacture of the OC are also disclosed.

A powder for dust cores includes an aggregate of soft magnetic particles, each of which includes a soft magnetic metal particle, and a ferrite film that covers a surface of the soft magnetic metal particle and includes ferrite crystal grains having a spinel structure. A diffraction peak derived from the ferrite crystal grains exists in a powder X-ray diffraction pattern. By a method for producing a powder for dust cores, a raw material powder that includes an aggregate of soft magnetic metal particles is prepared. Furthermore, many ferrite fine particles are formed on a surface of each of the soft magnetic metal particles of the raw material powder. Additionally, the ferrite fine particles are coarsely crystallized through heat treatment to form a ferrite film, which includes ferrite crystal grains having a spinel structure, on the surface of the each of the soft magnetic metal particles.

The present invention relates to a hydrothermal method for preparing a doped vanadium dioxide powder, the doped powder having a chemical composition of V.sub.1-XM.sub.XO.sub.2, 0<X0.5, and M is a doping element, which is introduced to control a particle size and a morphology of the doped powder, the doping element M is selected from a group consisting of manganese, iron, cobalt, nickel, copper, zinc, tin, indium, antimony, gallium, germanium, lead and bismuth, the method comprising a step of a precursor treatment of titrating a quadrivalent vanadium aqueous solution with a basic reagent to obtain a precursor suspension, wherein the precursor treatment involves titrating the quadrivalent vanadium aqueous solution until the emergence of the precursor suspension. The preparation methods for the present invention are easy to implement, low in cost, provide high yield, and are suitable for large scale production.

Provided is hexagonal strontium ferrite powder for magnetic recording, in which an activation volume is 800 to 1,500 nm.sup.3, a content of rare earth atom with respect to 100 atom % of iron atom is 0.5 to 5.0 atom %, and a rare earth atom surface portion uneven distribution is provided.