The United States of America as Represented by the Administrator of the

The United States of America as Represented by the Administrator

Andrew D Morrison

Taher Daud

A self-adjusting orifice for fluids nozzle includes a membrane constructed of a single piece of flexible or elastic material. This flexible material is shaped to fit into the outlet of a nozzle. The body of the membrane has at least two flow channels, from one face to the other, which directs two streams of water to cross at the opening of the nozzle or at some point beyond. The elasticity and thickness of the membrane is selected to match the range of expected pressures and fluid velocities. The orifice may have more than two flow channels, as long as they are aligned adjacent to one another and directed towards each other at the exit face. In a three orifice embodiment, one is directed upward, one is directed downward, and the one in the middle is directed forward. In this embodiment all three fluid streams intersect at some point past the nozzle opening. Under increased pressure the membrane will deform causing the orifices to realign in a more forward direction, causing the streams to intersect at a smaller angle. This reduces the force with which the separate streams impact each other, still allowing the separate streams to unify into a single stable spiralling stream in spite of the increased pressure.

Stable stream producing flexible orifice independent of fluid pressure

A nozzle assembly in a multi-element spherical shell generation system includes first and second side-by-side spaced apart nozzles and a web portion extending between and connecting the nozzles. The first nozzle has an inner orifice adapted to discharge a first filler material and an outer annular orifice separated from and defined in concentric relation about the inner orifice and adapted to discharge a first shell material. The second nozzle has an inner orifice adapted to discharge a second filler material and an outer annular orifice separated from and defined in concentric relation about the inner orifice and adapted to discharge a second shell material. A multi-element spherical shell can be formed through employment of the nozzle assembly by merger with one another after discharge from the outer orifices of the nozzles of a pair of adjacent annular streams of liquid or molten shell wall material of different compositions and encapsulation by the mixed shell wall materials of a common encapsulated core fluids also simultaneously discharged by the inner orifices nozzles. On the other hand, the pair of encapsulating streams of shell wall material can be of the same material which merge together and encapsulate core fluids of different compositions which will merge together after discharge from the nozzles.

Multi-element spherical shell generation

A method and apparatus are described which facilitate the growing of silicon ribbon. A container for molten silicon has a pair of passages in its bottom through which filaments extend to a level above the molten silicon, so as the filaments are pulled up they drag up molten silicon to form a ribbon. A pair of guides surround the filaments along most of the height of the molten silicon, so that the filament contacts only the upper portion of the melt. This permits a filament to be used which tends to contaminate the melt if it is in long term contact with the melt. This arrangement also enables a higher melt to be used without danger that the molten silicon will run out of any bottom hole.

Ribbon growing method and apparatus

Low-defect crystals are grown in a closed ampoule under a layer of encapsulant. After crystal growth, the crystal is separated from the melt and moved into the layer of encapsulant and cooled to a first temperature at which crystal growth stops. The crystal is then moved into the inert gas ambient in the ampoule and further cooled. The crystal can be separated from the melt by decanting the melt into an adjacent reservoir or by rotating the ampoule to rotate the crystal into the encapsulant layer.

Liquid encapsulated crystal growth

Crystals of wide band gap materials are produced by positioning a holder (106, 274) receiving a seed crystal (106) at the interface (36, 270) between a body (26, 206) of molten wide band gap material and an overlying layer (28 or 288) of temperature-controlled, encapsulating liquid. The temperature of the layer decreases from the crystallization temperature of the crystal at the interface with the melt to a substantially lower temperature at which formation of crystal defects does not occur, suitably a temperature of 200.degree. C. to 600.degree. C. After initiation of crystal growth, the leading edge of the crystal (212) is pulled through the layer until the leading edge of the crystal enters the ambient gas headspace (30, 265) which may also be temperature controlled. The length of the column of liquid encapsulant may exceed the length of the crystal such that the leading edge and trailing edge of the crystal are both simultaneously with the column of the crystal. The crystal can be pulled vertically by means of a pulling-rotation assembly (20) or horizontally by means of a low-angle withdrawal mechanism (210). The temperature of the encapsulating layer is controlled by heating and/or cooling elements (35, 230) submerged with the layers and connected in closed loop with power supplies (50, 52, 240) by means of temperature sensing elements (52, 239). These elements control and provide nucleation and growth of a more perfect crystal in the elongated, heat exchange, encapsulating fluid medium.

Total immersion crystal growth

The purity and perfection of a semiconductor is improved by depositing a patterned mask (12) of a material impervious to impurities of the semiconductor on a surface (14) of a blank (10). When a layer (40) of semiconductor is grown on the mask, the semiconductor will first grow from the surface portions exposed by the openings (16) in the mask (12) and will bridge the connecting portions of the mask to form a continuous layer (40) having improved purity, since only the portions (42) overlying the openings (16) are exposed to defects and impurities. The process can be reiterated and the mask translated to further improve the quality of grown layers.

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Altadena, CA, United States of America

Andrew D Morrison