Abstract: Disclosed herein are a process for producing acicular goethite particles comprising the steps of: blowing an oxygen-containing gas into a ferrous salt reaction solution containing colloidal ferrous hydroxide or iron-containing colloidal precipitates which is obtained by reacting an aqueous ferrous salt solution with less than one equivalent of an aqueous alkali hydroxide solution and/or an aqueous alkali carbonate solution based on Fe.sup.2 + in said aqueous ferrous salt solution so as to oxidize said colloidal ferrous hydroxide or iron-containing colloidal precipitates and to produce acicular goethite nucleus particles, adding to the resultant aqueous ferrous salt reaction solution containing said acicular goethite nucleus particles not less than one equivalent of an aqueous alkali carbonate solution based on Fe.sup.

Abstract: A magnetic material consisting essentially of A1 and 10 to 50 at. % of at least one capable of alloying with A1 to form quasicrystals (for example, 5 to 25 at. % of at least one member selected between Cu and Pd and 5 to 35 at. % of Mn) and up to 25 at. % of at least one element having a smaller atomic radius than those of the above elements (for example, B). The magnetic material is produced by adding, to a mixture consisting of A1 and at least one element capable of alloying with A1 to form quasicrystals and including at least one transition metal, at least one element having a smaller atomic radius than those of A1 and the above elements to dissolve the element having a smaller atomic radius in a solid solution form in a quasicrystalline phase. The thus obtained magnetic crystal is useful in various applications, such as magnetic recording heads, and a process for producing the same.

Abstract: An improved flux for use in preparing X-ray phosphors comprises an alkali metal sulfate, an alkali metal metaborate and, a strontium halide. By varying the concentration of the metaborate and strontium halide in the flux composition, the size and dry bulk density of the phosphor particles and the speed of the phosphor, respectively, can be controlled. Also disclosed is a process of making phosphors using the above flux, and X-ray intensifying screens containing such phosphors.

Abstract: A piezoelectric semiconductor is a single crystal composed mainly of ZnO having properties such as electrical conductivity of 10.sup.-11 .about.10.sup.-3 1/.OMEGA..multidot.cm suitable for use as an acoustoelectric element, by adding a given amount of H.sub.2 O.sub.2 to the alkali solvent, or by using NH.sub.4 OH in the alkali solvent, or by doping the ZnO single crystal with Li or a trivalent metal. The piezoelectric semiconductor can be suitably used as a ultrasonic transducer material of acoustoelectric type and can also be used as a material for ultrasonic amplification, an surface acoustic wave filter, a piezoelectric transducer, a fluorescent material for emitting a low-velocity electron beam, etc.

Abstract: This invention relates to terbium activated silicate luminescent glasses exhibiting reduced afterglow and enhanced luminescence due to incorporation therein of selected rare earth oxides of cerium, europium and gadolinium.

Abstract: Afterglow in a luminescent material in which a significant factor in afterglow is the release of holes from hole traps in the scintillator material is substantially reduced by adding cerium as a hole-trapping species to the scintillator composition which successfully competes with the hole traps in the basic scintillator composition. In gadolinium gallium garnet activated with chromium, the addition of cerium in the range of 0.2 to 0.255 weight percent reduces afterglow in this manner while exhibiting excellent stability to x-ray damage after exposure to an initial pair of x-ray pulses.

Abstract: It is an object of the present invention to provide a process of producing calcined materials for ferrite magnet, whereby foreign phase produced in calcined powders is eliminated and the ferrite magnet having a superior magnetic properties is obtained easily. Since mill scales roughly milled into a mean particle size of 20 .mu.m or less is subjected to primary oxidation treatment to change its oxidation percentage 95% or higher, and oxidized completely by secondary oxidation treatment in an inclined rotary kiln up to 700.degree. C. in an atmosphere containing O.sub.2 content of 8% to 10% at a charging side of raw material, foreign phase is not produced in the calcined powders during ferrite formation at high temperatures, and the ferrite magnet having a superior magnetic properties can be obtained.

Abstract: A rare earth oxysulfide phosphor of the formula (Ln.sub.1-x-y La.sub.x Ln'.sub.y).sub.2 O.sub.2 S wherein Ln is at least one element selected from the group consisting of Y, Gd, Sc and Lu, Ln' is at least one element selected from the group consisting of Eu, Tb, Sm, Er, Tm, Dy, Ho, Nd and Pr, and x and y are numbers within ranges of 0.005<x.ltoreq.0.07 and 0.0001.ltoreq.y.ltoreq.0.2, respectively.

Abstract: An indium borate phosphor of this invention is represented by formula (In.sub.l-a-b-c-d Tb.sub.a Eu.sub.b Sm.sub.c M.sub.d)BO.sub.3 wherein[1] if b.noteq.0 and c.noteq.0,1.times.10.sup.-6 .ltoreq.a.ltoreq.1.times.10.sup.-20<b.ltoreq.1.times.10.sup.-10<c.ltoreq.1.times.10.sup.-31.times.10.sup.-7 .ltoreq.d.ltoreq.1.times.10.sup.-2[2] if b=c=0,1.times.10.sup.-6 .ltoreq.a.ltoreq.1.times.10.sup.-11.times.10.sup.-7 .ltoreq.d.ltoreq.1.times.10.sup.-2and M is at least element selected from the group consisting of Ti, P, Si, and Ge. This phosphor has a higher bonding force between BO.sub.3 ions and ions of In or any other contained metal than that of a conventional indium borate phosphor. As a result, the current-brightness and burning characteristics of the indium borate phosphor can be greatly improved.

Abstract: The brightness and particle size of a niobium-activated yttrium tantalate x-ray phosphor can be increased by the addition of either barium fluorosilicate or calcium fluorosilicate thereto.

Abstract: Europium activated strontium tetraborate phosphor is reacted with strontium carbonate or strontium fluoride or ammonium fluoride in order to improve emission characteristics.

Abstract: A magnetic recording medium comprising a nonmagnetic substrate and at least one magnetic layer applied thereon and containing an acicular chromium dioxide uniformly distributed in a polymeric binder and additives and having a coercive force of at least 60 kA/m, a mean particle length of the chromium dioxide of less than 300 nm, whose factor HD according to the formula ##EQU1## where KT is the coercive force of the magnetic layer in [kA/m], measured in an external field of 380 kA/m, L is the mean particle length and .DELTA.L is the range of the particle size distribution, determined from the numerical distribution of the particle length, both measured in [nm], is greater than 1.85, and a process for the preparation of this chromium dioxide.

Abstract: The present invention provides a hexagonal magnetic ferrite pigment suitable for high density magnetic recording applications. The pigment is characterized by small particle size, a modified magnetoplumbite structure, and relatively high magnetic moment. The pigment is capable of being prepared by firing suitable precursor particles in air at temperatures below 850.degree. C.

Abstract: Disclosed herein are a process for producing acicular goethite particles comprising the step of: blowing an oxygen-containing gas into a ferrous salt reaction solution containing colloidal ferrous hydroxide or iron-containing colloidal precipitates which is obtained by reacting an aqueous ferrous salt solution with less than one equivalent of an aqueous alkali hydroxide solution, an aqueous alkali carbonate solution, or an aqueous alkali hydroxide and alkali carbonate solution based on Fe.sup.

Abstract: A process for producing BaFBr:Eu phosphors in which a slurry of an Eu halide, BaFBr and BaBr.sub.2 is spray dried to produce spherical agglomerates which are then fired and cooled by an inert atmosphere, washed to remove unreacted BaBr.sub.2 and dried to produce a powder.

Abstract: Long decay phosphors are disclosed that are comprised of rare-earth activated divalent, boron-substituted aluminates. In particular, the long decay phosphors are comprised ofMO.a(Al.sub.1-b B.sub.b).sub.2 O.sub.3 :cR,wherein0.5.ltoreq.a.ltoreq.10.0,0.0001.ltoreq.b.ltoreq.0.5 and0.0001.ltoreq.c.ltoreq.0.2,MO represents at least one divalent metal oxide selected from the group consisting of MgO, CaO, SrO and ZnO and R represents Eu and at least one additional rare earth element. Preferably, R represents Eu and at least one additional rare earth element selected from the group consisting of Pt, Nd, Dy and Tm.

Abstract: A low power loss Mn-Zn ferrite consists essentially of Fe.sub.2 O.sub.3, MnO and ZnO at a given mole ratio and contains given amounts of SiO.sub.2, CaO, niobium oxide and titanium oxide or antimony oxide as trace additives. This ferrite is suitable as a transformer material for switched mode power supply.

Abstract: An Mn-Zn-based single crystal ferrite composition containing an additive material essentially consisting of 0.2 to 2 mole % SnO.sub.2, 0.1 to 1 mole % CoO, 0.2 to 1 mole % CaCO.sub.3 and 0.02 to 1 weight % V.sub.2 O.sub.5 added to a host material essentially consisting of 51 to 54 mole % Fe.sub.2 O.sub.3, 27 to 33 mole % MnO and 16 to 20 mole % ZnO. A magnetic head manufactured from the single crystal ferrite generates an enhanced reproduction output and a reduced rubbing noise, thereby achieving a high picture quality and a high resolution of images.

Abstract: A color cathode-ray tube having a fluorescent screen of red-, blue- and green-emitting phosphors as image elements of a fluorescent layer, wherein at least one of said phosphors is coated with a double oxide of zinc and aluminum.

Abstract: The present invention provides a pigment-attached blue-emitting phosphor having attached a blue pigment which has fastness and chemical stability and is excellent in reflection spectrum characteristics, and a color cathode-ray tube having a blue-emitting fluorescent layer containing the blue pigment formed on the inner surface of a face plate.The present invention also provides a pigment-attached blue-emitting phosphor having a CoO.ZnO.SiO.sub.2 type blue pigment attached thereto, and a color cathode-ray tube provided with a blue-emitting fluorescent layer containing the blue pigment particles on the inner surface of a face plate.