Abstract: The ventricular catheter 10 of the present invention comprises a multiplicity of inlet microtubules 12. Each microtubule has both a large opening 16 at its inlet end and a multiplicity of microscopic openings 18 along its lateral surfaces.The microtubules are perforated by a new and novel ion beam sputter etch technique. The holes are etched in each microtubule by directing an ion beam 20 through an electro formed metal mesh mask 28 producing perforations having diameters ranging from about 14 microns to about 150 microns.This combination of a multiplicity of fluoropolymer microtubes, the numerous small holes provided in the lateral surfaces of the tubes, and the hydra-like distribution of the tubes provide a new and novel catheter. This structure assures a reliable means for shunting cerebrospinal fluid from the cerebral ventricles to selected areas of the body.

Abstract: A heat transparent high intensity solar cell has improved efficiency.A surface of each solar cell (10,16,22) has a plurality of grooves (12,14,18,20,24). Each groove has a vertical face (26,30) and a slanted face (28,32) that is covered by a reflecting metal (34,36).Light rays (38,40) are reflected from the slanted face through the vertical face where they traverse a photovoltaic junction (60). As the light rays travel to the slanted face of an adjacent groove, they again traverse the junction. The underside of the reflecting coating directs the light rays toward the opposite surface of solar cell as they traverse the junction again. When the light rays travel through the solar cell and reach the saw toothed grooves on the under side, the process of reflection and repeatedly traversing the junction again takes place. The light rays ultimately emerge from the solar cell as shown in FIG. 4.

Abstract: This invention is concerned with reducing the operating temperature and increasing the output of a solar cell.A solar cell (10) constructed in accordance with the invention carries electrodes (22) in a grid finger pattern on its back surface (12). These electrodes are sintered at the proper temperature to provide good ohmic contact.After sintering, a reflective material (24) is deposited on the back surface by vacuum evaporation. Thus, the application of the back surface reflector is separate from the back contact formation.Back surface reflectors formed in conjunction with separate grid finger configuration back contacts are more effective than those formed by full back metallization of the reflector material.

Abstract: According to the invention a metal oxide coating is plated onto a metal substrate at the cathode from an acid solution which contains an oxidizing agent. The process is particularly useful for producing solar panels.Conventional plating at the cathode avoids the presence of oxidizing agents. Coatings made in accordance with the invention are stable both at high temperatures and while under the influence of high photon flux in the visible range.

Abstract: This invention is directed to a method of joining the surfaces of two metal structures in a mechanical bond. The joining process can be performed in either art or vacuum. The metal surfaces of the structures 10 and 12 that are to be bonded are exposed to an ion beam 14 together with a target 18 of low sputtering yield material. This material deposits on the surfaces and creates sites of sputter resistance which evolve into peaks 20 of a cone like surface microstructure. The textured metal surfaces are arranged in face to face relationship and compressed together with plastic deformation which mechanically interlocks the cone 22. A large interface area is produced which minimizes thermal and electrical losses. Also, no electrical power or heat is required during metal joining.

Abstract: A specially textured surface of pyrolytic graphite exhibits extremely low yields of secondary electrons and reduced numbers of reflected primary electrons after impingement of high energy primary electrons.An ion flux having an energy between 500 eV and 1000 eV and a current density between 1.0 mA/cm.sup.2 and 6.0 mA/cm.sup.2 produces surface roughening or texturing which is in the form of needles or spines.Such textured surfaces are especially useful as anode collector plates in high efficiency electron tube devices.

Abstract: This invention is concerned with providing improved surface texturing for adhesive bonding, metal bonding, substrate plating, decal substrate preparation, and biomedical implant applications. The invention is particularly concerned with epoxy bonding to polymers that typically exhibit low adhesion and bonding metals to a desired thickness to a polymer substrate.The surface 12 to be bonded is first dusted in a controlled fashion to produce a disbursed layer of fine mesh particles 14 which serve as masks. The surface texture is produced by impinging gas ions on the masked surface. The textured surface takes the form of pillars or cones.The bonding material, such as a liquid epoxy, flows between the pillars which results in a bond having increased strength. For bonding metals a thin film of metal is vapor or sputter deposited onto the textured surface. Electroplating or electroless plating is then used to increase the metal thickness to the desired amount.

Abstract: This invention is concerned with improving adhesion, friction and wear properties of sputtered refractory coatings on substrates of materials that form stable nitrides.Each substrate (10) is placed directly below a titanium carbide target (16) of a commercial radiofrequency diode apparatus (14) in a vacuum chamber (26). Nitrogen is bled into the system through a nozzle (3) resulting in a small partial pressure of about 0.5% to 2.5% during the first two minutes of deposition. The flow of nitrogen is then stopped, and the sputtering ambient is reduced to pure argon through a nozzle (28) without interrupting the sputtering process.When nitrogen is deliberately introduced during the crucial interface formation, some of the titanium at the interface reacts to form titanium nitride while the metal of the substrate also forms the nitride. These two nitrides atomically mixed together in the interfacial region (38) act to more strongly bond the growing titanium carbide coating (12) as it forms on the substrate (10).

Abstract: A high voltage multijunction solar cell is provided wherein a plurality of discrete voltage generating regions or unit cells are formed in a single generally planar semiconductor body (12). The unit cells comprise a doped regions (20, 22) of opposite conductivity type separated by a gap or undiffused region (24). Metal contacts (26) connect adjacent cells together in series so that the output voltages of the individual cells are additive. In some embodiments, doped field regions (14) separated by gap (16) overlie the unit cells but the cells may be formed in both faces of the wafer (FIG. 2).

Abstract: NiCrAl alloys are improved by the addition of zirconium. These alloys are in the .beta. or .gamma./.gamma.'+.beta. region of the ternary system.Zirconium is added in a very low amount between 0.06 and 0.20 weight percent. There is a narrow optimum zirconium level at the low value of 0.13 weight percent.Maximum resistance to cyclic oxidation is achieved when the zirconium addition is at the optimum value.

Abstract: This invention is concerned with a seal having a high temperature abradable lining material encircling the tips of turbine blades in turbomachinery. The invention is particularly directed to maintaining the minimum operating clearances between the blade tips and the lining of a high pressure turbine.A low temperature easily decomposable material, such as a polymer, in powder form is blended with a high temperature oxidation resistant metal powder. The two materials are simultaneously deposited on a substrate formed by the turbine casing. Alternately, the polymerpowder may be added to the metal powder during plasma spraying.A ceramic layer is then deposited directly onto the metal-polymer composite. The polymer additive mixed with the metal is then completely volatilized to provide a porous layer between the ceramic layer and the substrate.Thermal stresses are reduced by virtue of the resulting porous structure which affords a cushion effect.

Abstract: A method is provided for making a high voltage multijunction solar cell which comprises a plurality of discrete voltage generating regions, or unit cells, which are formed in a single semiconductor wafer (10) and are connected together so that the voltages of the individual cells are additive. The unit cells comprise doped regions of opposite conductivity types (30, 32) separated by a gap. The method includes forming V-shaped grooves (16) in the wafer and thereafter orienting the wafer so that ions of one conductivity type can be implanted in one face (e.g., 16a) of the groove while the other face (e.g., 16b) is shielded. A metallization layer (22) is applied and selectively etched away to provide connections between the unit cells.

Abstract: This invention is concerned with improving adhesion, friction and wear properties of sputtered refractory coatings on substrates of materials that form stable nitrides.Each substrate (10) is placed directly below a titanium carbide target (16) of a commercial radiofrequency diode apparatus (14) in a vacuum chamber (26). Nitrogen is bled into the system through a nozzle (30) resulting in a small partial pressure of about 0.5% to 2.5% during the first two minutes of deposition. The flow of nitrogen is then stopped, and the sputtering ambient is reduced to pure argon through a nozzle (28) without interrupting the sputtering process.When nitrogen is deliberately introduced during the crucial interface formation, some of the titanium at the interface reacts to form titanium nitride while the metal of the substrate also forms the nitride. These two nitrides atomically mixed together in the interfacial region (38) act to more strongly bond the growing titanium carbide coating (12) as it forms on the substrate (10).

Abstract: This invention is directed to an improved thermal barrier system by improving the adherence between a ceramic thermal barrier coating and a metal bond coating. First a primer film is deposited on the bond coat by ion sputtering a ceramic film thereon. A ceramic thermal barrier coating is then plasma-sprayed onto this primer film. This improves the integrity and strength of the interface between the plasma-sprayed ceramic layer and metallic bond coat which insures stronger adherence between the metal and the ceramic.

Abstract: This invention is concerned with fabricating textured surfaces on polymers without altering their surface chemistries.A surface of a fluorocarbon polymer 10 is exposed to a beam 12 of ions from a source 14 to texture it. The polymer 18 which is to be surface-roughened is then cast over the textured surface 20 of the fluorocarbon polymer. After curing, the cast polymer is peeled off the textured fluorocarbon polymer, and the peeled off surface 22 has a negative replica of the textured surface 20.The microscopic surface texture provides large surface areas for adhesive bonding. In cardiovascular prosthesis applications the surfaces are relied on for the development of a thin adherent well nourished thrombus.

Abstract: A low cost coating protects metallic base system substrates from high temperatures, high gas velocity oxidation, thermal fatigue and hot corrosion. The coating is particularly useful for protecting vanes and blades in aircraft and land based gas turbine engines.A lacquer slurry comprising cellulose nitrate containing high purity silicon powder is sprayed onto the superalloy substrates. The silicon layer is then aluminized to complete the coating.The Si-Al coating is less costly to produce than advanced aluminides and protects the substrate from oxidation and thermal fatigue for a much longer period of time than the conventional aluminide coatings. While more expensive Pt-Al coatings and physical vapor deposited MCrAlY coatings may last longer or provide equal protection on certain substrates, the Si-Al coating exceeded the performance of both types of coatings on certain superalloys in high gas velocity oxidation and thermal fatigue.

Abstract: A gas path seal suitable for use with a turbine engine or compressor is provided. A shroud wearable or abradable by the abrasion of the rotor blades of the turbine or compressor shrouds the rotor blades. A compliant backing surrounds the shroud. The backing is a yieldingly deformable porous material covered with a thin ductile layer. A mounting fixture surrounds the backing.

Abstract: The object of the invention is to improve the film stiffness of a face seal without increasing the sealing and dam area.The improved sealing apparatus (16) has a primary seal ring (20) in the form of a nose piece. A spring (24) forces a sealing surface (28) on the seal ring into sealing contact with a seat (18) to form a face seal. A circumferential clearance seal is formed in series with this face seal by a lip (34) on the nose piece. The width of the surface (36) of the lip is substantially the same as the width of the sealing surface (28) on the face seal. Also the clearance between the surface (36) on the lip and the shaft (10) is substantially the same as the spacing between the face sealing surfaces (28 and 30) on the face seal when the shaft is rotating.The circumferential clearance seal restricts the flow of fluid from a main cavity (14) to an intermediate cavity (32) with a resulting pressure drop.

Abstract: A self-reconfiguring solar cell array wherein some of the cells are switched so that they can be either in series or in shunt within the array. This feature of series or parallel switching of cells allows the array to match the load to achieve maximum power transfer. Automatic control is used to determine the conditions for maximum power operation and to switch the array into the appropriate configuration necessary to transfer maximum power to the load.

Abstract: A rocket propellant feed system utilizing a bleed turbopump to supercharge a topping turbopump. The bleed turbopump is of a low pressure type to meet the cavitation requirements imposed by the propellant storage tanks. The topping turbopump is of a high pressure type and develops 60 to 70 percent of the pressure rise in the propellant.