Abstract: Disclosed is a dielectric material comprising: 100 parts by weight of a main component having a composition represented by formula: xBaO—yRE2O3—zTiO2, wherein RE represents at least one rare earth element and x+y+z=100 mol %; 5 parts by weight or less of at least one alkali metal oxide; and 5 parts by weight or less of Bi2O3.

Abstract: Disclosed is a dielectric material comprising: a main ingredient having a composition represented by xBaO-yRE2O3-zTiO2, wherein RE represents at least one rare earth element, and x+y+z=100 mol %; at least one alkali metal oxide; and an ingredient derived from an oxygen supplying agent which releases oxygen on heating.

Abstract: Disclosed is a dielectric ceramic material represented by composition formula: (uLi2O—vNa2O)—wSm2O3—xCaO—yTiO2, having a solid solution structure made up of perovskite crystals represented by Ca1−xSm2x/3TiO3, perovskite crystals represented by Li1/2Sm1/2TiO3, and perovskite crystals represented by Na1/2Sm1/2TiO3. Substitution of part of Ti in the composition with at least one of Ga and Al provides a dielectric ceramic material with a particularly increased value of unloaded quality coefficient. The absolute value of the temperature coefficient of resonance frequency is controlled to a small value by adjusting the proportions of Li and Na.

Abstract: A dielectric material based on BaO-RE.sub.2 O.sub.3 -TiO.sub.2 is disclosed, which has a relatively high relative permittivity .epsilon..sub.r, a small absolute value of the temperature coefficient of resonance frequency .tau..sub.f and a high coefficient of unloaded quality Q.sub.u. Processes for producing the dielectric material are also disclosed. The dielectric material comprises 100 parts by weight of main ingredients having a composition represented by xBaO-yRE.sub.2 O.sub.3 -zTiO.sub.2 (wherein RE represents a rare earth element and x+y+z=100) and up to 5 parts by weight of at least one alkali metal oxide. This alkali metal oxide serves to improve .epsilon..sub.r and Q.sub.u without a considerable sacrifice of .tau..sub.f. The RE preferably consists of samarium or a combination of samarium with neodymium and/or lanthanum.

Abstract: A dielectric material is disclosed which has a small absolute value of the temperature coefficient of resonance frequency and a high coefficient of unloaded quality. Also disclosed are a process for producing the dielectric material and multilayer and other circuit boards containing the dielectric material. The dielectric material is a highly densified material having a water absorption lower than 0.1%, which is obtained by mixing 95.5 to 99.5 percent by weight mixture of a glass frit and a strontium compound with 0.5 to 4.5 percent by weight titanium dioxide, compacting the resultant mixture, and sintering the compact at a relatively low temperature around 930.degree. C. This dielectric material is a glass ceramic containing strontium anorthite (SrAl.sub.2 Si.sub.2 O.sub.8) as the main crystalline phase, and may contain the TiO.sub.2, which remains unchanged after sintering. The absolute value of the temperature coefficient of resonance frequency of the dielectric material is 20 ppm/.degree. C.

Abstract: Dielectric materials are disclosed that are based on BaO--ZnO--Ta.sub.2 O.sub.5 represented by the formula Ba(Zn.sub.1/3 Ta.sub.2/3)O.sub.3. Ba has been partly replaced by K and either Zn or Ta has been replaced by at least one element selected from Mg, Zr, Ga, Ni, Nb, Sn. The dielectric materials have a relatively high permittivity, a small absolute value of the temperature coefficient of resonance frequency, and a high unloaded quality factor. A method for producing the dielectric materials is also disclosed which includes mixing given amounts of starting materials, such as, for example, BaCO.sub.3, ZnO, Ta.sub.2 O.sub.5, K.sub.2 CO.sub.3, MgCO.sub.3, SnO.sub.2 or ZrO.sub.2, compacting the mixture to produce a compact, sintering the compact in an oxidizing atmosphere such as, for example, air, at 1,400 and 1,600.degree. C., more preferably at 1,550 to 1,600.degree. C. for 2 hours, and then heating the sintered compact at a temperature lower than the sintering temperature by from 50 to 250.degree. C., e.g.

Abstract: A catalytic material for removing nitrogen oxides comprises a complex oxide as main phase. The complex oxide has a spinel structure and contains metallic elements of Al, Ga, and Zn. The mole fraction x (%) of Zn on oxide basis is greater than 0 and less than 50. Nitrogen-oxides-containing gas and a reductant such as methane or propylene are brought into contact with the catalytic material so as to remove, through reduction, nitrogen oxides from the nitrogen-oxides-containing gas. The catalytic material can be used to remove nitrogen oxides contained in exhaust gas from an automobile or the like. The catalytic material can remove nitrogen oxides even in exhaust gas of a high oxygen concentration and requires no toxic reductant such as ammonia.