A screw smelting machine melts raw materials with a different chemical ratio in a mixing funnel in a feeding order to prevent the long-range diffusion of a melt, and controls outflow at a suitable speed. A centrifugal casting machine solidifies the melt with the ingredients gradient varying into a radial ingredient gradient material by a centrifugal casting style. A temperature sensor monitors temperature of an outer surface of a centrifuge cavity of the centrifugal casting machine during centrifugal casting, and transmits the temperature to a control platform. The control platform determines an optimal flow rate of the melt at an end of screw rod according to ingredient gradient of ingredient radial-gradient pipe materials and a thickness of each component gradient material required with preparation, in combination with a real-time data fed back from the temperature sensor, and feeds back to a feeding end.

A laminated or single layer glass cylinder and its method of making are disclosed. The laminated cylinder glass is a precursor component to enable making subsequent drawn tubing having high optical quality. The laminated cylinder glass may comprise a first layer of glass as a clad glass and a second layer of glass as a core glass. The second layer of glass may be bound to the first layer of glass. The second layer may have a higher CTE from about 5×10.sup.−7/° C. to about 100×10.sup.−7/° C. than the first layer of glass. The first layer and second layer of glass may have different softening points within about 200° C. of each other. In some embodiments, the first layer and second layer of glass may have different softening points from about 50° C. to about 200° C. of each other.

A screw smelting machine melts raw materials with a different chemical ratio in a mixing funnel in a feeding order to prevent the long-range diffusion of a melt, and controls outflow at a suitable speed. A centrifugal casting machine solidifies the melt with the ingredients gradient varying into a radial ingredient gradient material by a centrifugal casting style. A temperature sensor monitors temperature of an outer surface of a centrifuge cavity of the centrifugal casting machine during centrifugal casting, and transmits the temperature to a control platform. The control platform determines an optimal flow rate of the melt at an end of screw rod according to ingredient gradient of ingredient radial-gradient pipe materials and a thickness of each component gradient material required with preparation, in combination with a real-time data fed back from the temperature sensor, and feeds back to a feeding end.

A laminated or single layer glass cylinder and its method of making are disclosed. The laminated cylinder glass is a precursor component to enable making subsequent drawn tubing having high optical quality. The laminated cylinder glass may comprise a first layer of glass as a clad glass and a second layer of glass as a core glass. The second layer of glass may be bound to the first layer of glass. The second layer may have a higher CTE from about 510.sup.7/ C. to about 10010.sup.7/ C. than the first layer of glass. The first layer and second layer of glass may have different softening points within about 200 C. of each other. In some embodiments, the first layer and second layer of glass may have different softening points from about 50 C. to about 200 C. of each other.

A laminated or single layer glass cylinder and its method of making are disclosed. The laminated cylinder glass is a precursor component to enable making subsequent drawn tubing having high optical quality. The laminated cylinder glass may comprise a first layer of glass as a clad glass and a second layer of glass as a core glass. The second layer of glass may be bound to the first layer of glass. The second layer may have a higher CTE from about 510.sup.7/ C. to about 10010.sup.7/ C. than the first layer of glass. The first layer and second layer of glass may have different softening points within about 200 C. of each other. In some embodiments, the first layer and second layer of glass may have different softening points from about 50 C. to about 200 C. of each other.

A laminated or single layer glass cylinder and its method of making are disclosed. The laminated cylinder glass is a precursor component to enable making subsequent drawn tubing having high optical quality. The laminated cylinder glass may comprise a first layer of glass as a clad glass and a second layer of glass as a core glass. The second layer of glass may be bound to the first layer of glass. The second layer may have a higher CTE from about 510.sup.7/ C. to about 10010.sup.7/ C. than the first layer of glass. The first layer and second layer of glass may have different softening points within about 200 C. of each other. In some embodiments, the first layer and second layer of glass may have different softening points from about 50 C. to about 200 C. of each other.

A laminated or single layer glass cylinder and its method of making are disclosed. The laminated cylinder glass is a precursor component to enable making subsequent drawn tubing having high optical quality. The laminated cylinder glass may comprise a first layer of glass as a clad glass and a second layer of glass as a core glass. The second layer of glass may be bound to the first layer of glass. The second layer may have a higher CTE from about 510.sup.7/ C. to about 10010.sup.7/ C. than the first layer of glass. The first layer and second layer of glass may have different softening points within about 200 C. of each other. In some embodiments, the first layer and second layer of glass may have different softening points from about 50 C. to about 200 C. of each other.

A method for producing a dental prosthesis based on lithium silicate glass or lithium silicate glass-ceramic, including the steps of: melting a powder mixture containing at least SiO.sub.2, Li.sub.2O, Al.sub.2O.sub.3; producing spherical, lens-shaped or rod-shaped glass particles solidified from the melt; portioning the glass particles and filling them into a crucible; melting the glass particles in the crucible and setting a viscosity v, wherein 4 dPa.Math.sv80 dPa.Math.s; casting the thus produced melt into a negative mold which is enclosed by an embedding compound and corresponds to the dental prosthesis and; solidifying the melt in the negative mold, and crystallizing lithium metasilicate and/or lithium disilicate from the solidified melt.

A method for producing a dental prosthesis based on lithium silicate glass or lithium silicate glass-ceramic, including the steps of: melting a powder mixture containing at least SiO.sub.2, Li.sub.2O, Al.sub.2O.sub.3; producing spherical, lens-shaped or rod-shaped glass particles solidified from the melt; portioning the glass particles and filling them into a crucible; melting the glass particles in the crucible and setting a viscosity v, wherein 4 dPa.Math.sv80 dPa.Math.s; casting the thus produced melt into a negative mold which is enclosed by an embedding compound and corresponds to the dental prosthesis and; solidifying the melt in the negative mold, and crystallizing lithium metasilicate and/or lithium disilicate from the solidified melt.

The present invention relates to a process for the preparation of hulk or thin-film single-crystals of cubic sesquioxides (space group No. 206, Ia-3) of scandium, yttrium or rare earth metals doped or not doped with lanthanide ions having a valency of +III by a high-temperature flux growth technique and to the applications of the nondoped single-crystals obtained according to this process, in particular in the optical field.