Compositions for the production of rare earth-ferromagnetic metal permanent magnets comprise mixtures of rare earth-ferromagnetic metal alloy powder and a lesser amount of a powdered second-phase sintering aid, wherein there is added up to about 2 percent by weight of a particulate refractory oxide, carbide, or nitride additive. Permanent magnets are prepared by mixing the components, aligning the mixture in a magnetic field, pressing and sintering. The refractory material inhibits grain growth ...

An article of manufacture marked with compositions comprising rare earth metal compounds which, due to their luminescence when irradiated with UV light, are suitable in particular for the marking of security-relevant items, such as documents or data carriers.

The present invention is to a method of adapting optical rare-earth-doped waveguide (10) having a plurality of transverse propagation modes, such that in use, signal gains of non-fundamental modes of the waveguide are attenuated relative to a signal gain of a fundamental mode of the waveguide. The waveguide (10) has a light-guiding region (45) defined by a refractive index-modifying dopant, such as Ge, which has a thermal diffusion coefficient at temperature T in the waveguide greater than a the...

The apparatus is a selective radiation emitter to be used in conjunction with a photocell for thermophotovoltaic generation of electricity from heat. One embodiment of the emitter is a layer of selectively radiating rare earth oxide bonded onto a heated base metal layer by the use of an intermediate thin layer of porous metal powder. Another embodiment is an emitter of a thick metal powder layer combined with a rare earth oxide which is formed into the voids in the metal powder structure and bon...

A method for enriching cancer cells such as prostate cancer cells in a bodily fluid sample is disclosed comprising (a) obtaining the sample comprising cancer cells and non-rare cells; (b) subjecting the sample to multiple density gradient separation comprising a first density gradient and a second density gradient, wherein the second density gradient is greater than the first density gradient, and producing a first fluid comprising an increased concentration of cancer cells of a first density, a...

A process for preparing phosphor particles of a host oxide doped with a rare earth or manganese which comprises: preparing an aqueous solution of salts of the host ion and of the dopant ion and a water soluble compound which decomposes under the reaction conditions to convert said salts into hydroxycarbonate, heating the solution so as to cause said compound to decompose, recovering the resulting precipitate and calcining it at a temperature of at least 500.degree. C. Substantially monocrystalli...

A system for controlling light propagation in a multiple tube display. Each tube has a pair of electrodes disposed at opposite positions, one of which is excited. Control means excites one of the electrodes of a first tube at a variable increasing power level to cause light intensity to sweep therethrough. A second control circuit controls excitation of one of the electrodes of the other tube to provide a variable increasing power level to cause light intensity to sweep therethrough.

A process for preparing a rare earth nitrate solution in which rare earth hydroxides containing quadrivalent cerium are dissolved in nitric acid with the addition of hydrogen peroxide. The change in oxidation-reduction E.M.F. may be used to control the addition of peroxide to prevent formation of quadrivalent cerium ions in the nitrate solution.

Novel rare earth oxides having a large specific surface of at least 40 m.sup.2 /g, well adapted for catalysis, are prepared (i) by reacting at least one rare earth salt with a strong base in the presence of carboxylate ions, or by reacting at least one rare earth carboxylate with a strong base, to produce a true rare earth hydroxide, (ii) separating the precipitate thus produced, and then (iii) washing and (iv) calcining such precipitate.

A device for processing rare earths with a grinding vessel having ball-shaped grinding bodies and an agitator for rotating the bodies, said vessel having a connection for the supply of liquid hexane andhaving near the bottom a tapping opening communicating with an evaporation vessel, said vessels having connections with a vacuum source and for the supply of rare gas, the evaporation vessel having an outlet for the ground product, and an outlet for the vaporlike products communicating with a cond...