Disclosed herein are doped thermoelectric ceramic oxide compositions comprising a calcium cobaltite ceramic. The doped thermoelectric ceramic oxide compositions can have a formula Ca.sub.3-xM.sup.2.sub.xCo.sub.4O.sub.9M.sup.1.sub.y, where M.sup.1 represents a first metal dopant, M.sup.2 represents a second metal dopant, x is a number having a value of from about 0.00 to about 3.00, and y is a number having a value of from about 0.01 to about 0.50. The doped thermoelectric ceramic oxide compositions have an increased energy conversion efficiency as compared to an undoped or conventional thermoelectric ceramic oxide materials. Also disclosed are methods for making the doped thermoelectric ceramic oxide compositions. Products and devices are disclosed comprising the thermoelectric ceramic oxide compositions, e.g., solid-state conversion devices that can utilize heat to generate electricity. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

The present invention provides a ferrite sintered magnet comprising ferrite crystal grains having a hexagonal structure, wherein the ferrite sintered magnet comprises metallic elements at an atomic ratio represented by formula (1). In formula (1), R is at least one element selected from the group consisting of Bi and rare-earth elements, and R comprises at least La. In formula (1), w, x, z and m satisfy formulae (2) to (5). The above-mentioned ferrite sintered magnet further has a coefficient of variation of a size of the crystal grains in a section parallel to a c axis of less than 45%.

Ca.sub.1-w-xR.sub.wSr.sub.xFe.sub.zCo.sub.m(1)

0.360w=0.420(2)

0.110x0.173(3)

8.51z9.71(4)

0.208m0.269(5)

Disclosed herein are embodiments of composite hexagonal ferrite materials formed from a combination of Y phase and Z phase hexagonal ferrite materials. Advantageously, embodiments of the material can have a high resonant frequency as well as a high permeability. In some embodiments, the materials can be useful for magnetodielectric antennas.

Thermochemical storage materials having the general formula A.sub.xA.sub.1-xB.sub.yB.sub.1-yO.sub.3-, where A=La, Sr, K, Ca, Ba, Y and B=Mn, Fe, Co, Ti, Ni, Cu, Zr, Al, Y, Cr, V, Nb, Mo, are disclosed. These materials have improved thermal storage energy density and reaction kinetics compared to previous materials. Concentrating solar power thermochemical systems and methods capable of storing heat energy by using these thermochemical storage materials are also disclosed.

This ferrite sintered magnet comprises ferrite phases having a magnetoplumbite type crystal structure. This magnet comprises an element R, an element M, Fe, Co, B, Mn and Cr, the element R is at least one element selected from rare earth elements including Y, the element M is at least one element selected from the group consisting of Ca, Sr and Ba, with Ca being an essential element, and when an atomic composition of metallic elements is represented by R.sub.1-xM.sub.xFe.sub.m-yCo.sub.y, x, y and m satisfy formulae:

0.2x0.8(1)

0.1y0.65(2)

3m<14(3).

Additionally, a content of B is 0.1 to 0.4% by mass in terms of B.sub.2O.sub.3, a content of Mn is 0.15 to 1.02% by mass in terms of MnO, and a content of Cr is 0.02 to 2.01% by mass in terms of Cr.sub.2O.sub.3.

Provided is a novel compound which can be used for positive-electrode catalysts of metal-air batteries. The melilite-type complex oxide according to the present invention is represented by a general formula (BazSr1z)2CoxFe22x(SiyGe1y)1+xO7 (in the formula, 0x1, 0y1, and 0z1, excluding the case where x=1, y=1, and z=0, the case where x=1, y=1, and z=1, the case where x=1, y=0, and z=0, the case where x=1, =0, and z=1, the case where x=0, y=0, and z=0, and the case where x=0, y=0, and z=1).

This ferrite sintered magnet comprises metallic elements at an atomic ratio represented by formula (1):

Ca.sub.1-w-xR.sub.wSr.sub.xFe.sub.zCo.sub.m (1) in formula (1), R is at least one element selected from the group consisting of rare-earth elements and Bi, and R comprises at least La, in formula (1), w, x, z and m satisfy formulae (2) to (5):

0.360w0.420 (2)

0.110x0.173 (3)

8.51z9.71 (4)

0.208m0.269 (5), and in a section parallel to an axis of easy magnetization, when the number of total ferrite grains is N and the number of ferrite grains having a stacking fault is n, 0n/N0.20 is satisfied.

Disclosed herein are embodiments of composite hexagonal ferrite materials formed from a combination of Y phase and Z phase hexagonal ferrite materials. Advantageously, embodiments of the material can have a high resonant frequency as well as a high permeability. In some embodiments, the materials can be useful for magnetodielectric antennas.

The invention relates to a method for preparing a composite metal oxide hollow fibre. A certain stoichiometry of composite metal oxide raw material and a polymer binding agent are added to an organic solvent, and mixed mechanically to obtain an evenly dispersed spinning solution having a suitable viscosity. After defoaming treatment, the spinning solution is extruded through a spinneret and, after undergoing a certain dry spinning process, enters an external coagulation bath; during this period, a phase inversion process occurs and composite metal oxide hollow fibre blanks are formed. The blanks are immersed in the external coagulation bath and the organic solvent is displaced; after natural drying, the blanks undergo a heat treatment process; during this period, polymer burn off, in situ reaction, and in situ sintering processes occur to obtain the composite metal oxide hollow fibre.

Thermochemical storage materials having the general formula A.sub.xA.sub.1-xB.sub.yB.sub.1-yO.sub.3-, where A=La, Sr, K, Ca, Ba, Y and B=Mn, Fe, Co, Ti, Ni, Cu, Zr, Al, Y, Cr, V, Nb, Mo, are disclosed. These materials have improved thermal storage energy density and reaction kinetics compared to previous materials. Concentrating solar power thermochemical systems and methods capable of storing heat energy by using these thermochemical storage materials are also disclosed.