Abstract:
Methods and apparatus for unmanned long endurance flights are provided herein. In some embodiments, a lightweight solar wing for unmanned aircraft may include at least one airfoil profile, a top surface, a bottom surface, a leading edge, a trailing edge, wing tips, and at least one photovoltaic cell, wherein the surfaces and edges follow an arched bow shape across a span of the wing. In some embodiments, an unmanned solar-powered aircraft may include at least one lightweight solar wing as described above, at least one fuselage, and at least one propeller, wherein the fuselage is placed below the solar wing and contains an electric motor, battery, and electronics.
Abstract:
A method for forming a high purity, copper indium gallium selenide (CIGS) bulk material is disclosed. The method includes sealing precursor materials for forming the bulk material in a reaction vessel. The precursor materials include copper, at least one chalcogen selected from selenium, sulfur, and tellurium, and at least one element from group IIIA of the periodic table, which may be selected from gallium, indium, and aluminum. The sealed reaction vessel is heated to a temperature at which the precursor materials react to form the bulk material. The bulk material is cooled in the vessel to a temperature below the solidification temperature of the bulk material and opened to release the formed bulk material. A sputtering target formed by the method can have an oxygen content of 10 ppm by weight, or less.
Abstract:
A method and apparatus for forming a thin film of a copper indium gallium selenide (CIGS)-type material are disclosed. The method includes providing first and second targets in a common sputtering chamber. The first target includes a source of CIGS material, such as an approximately stoichiometric polycrystalline CIGS material, and the second target includes a chalcogen, such as selenium, sulfur, tellurium, or a combination of these elements. The second target provides an excess of chalcogen in the chamber. This can compensate, at least in part, for the loss of chalcogen from the CIGS-source in the first target, resulting in a thin film with a controlled stoichiometry which provides effective light absorption when used in a solar cell.
Abstract:
A chalcogenide glass that is doped with praseodymium and contains a rare earth metal is disclosed. The rare earth metal is at least 10 mole percent of the metals in the glass. The concentration of the praseodymium in the glass is at least 200 ppm. The chalcogenide glass, when formed into an amplifier for an optical fiber transmission system, efficiently amplifies optical signals in the signal band of 1.3 .mu.m.
Abstract:
Formation of stretchable photovoltaic devices and carriers is described. In some examples, a formation method includes: forming a stretchable carrier including a stretchable part having a given length, the given length being operable to change in response to a force being applied to the stretchable carrier; depositing a photovoltaic cell over a surface of the stretchable carrier; and interconnecting the photovoltaic cell to output terminals.
Abstract:
Relatively large bodies of low-alkali silicate and other glass can be prepared conveniently by a particulate sol-gel process. The glass comprises at least 85 mole % SiO.sub.2, 1-12 mole % oxide of one or more of Li, Na, K, Rb, Cs, Ti and Zr, 0-6 mole % of oxide of Al, and optionally at most 2.5 mole % of oxide of elements other than Si, Li, Na, K, Rb, Cs, Ti, Zr and Al. The process comprises forming particles from a first sol that comprises Si and one or more of Li, Na, K, Rb, Cs, Ti and Zr, and optionally additionally comprises Al. The process further comprises forming a second sol by dispersing the particles in an aqueous liquid, gelling the second sol, and heat treating the resulting gel body such that the glass results.
Abstract:
An active optical device comprises a glass, waveguiding structure disposed on a substantially planar principal surface of a substrate. The structure includes a silica-based, erbium-doped active core. The active core has an erbium-to-silicon atomic ratio of at least about 0.01, an absolute erbium concentration of at least about 1.4.times.10.sup.20 atoms per cubic centimeter, and a radiative lifetime of the erbium lasing level of at least about 7 milliseconds. Also disclosed is a method for forming an active optical device, including the step of depositing an erbium-doped active core by sputtering.
Abstract:
A stretchable photovoltaic device, a stretchable photovoltaic module and a carrier for facilitating formation of a stretchable photovoltaic device and/or module are provided. The stretchable photovoltaic device includes a stretchable part, at least one photovoltaic cell and a surface over which that at least one photovoltaic cell is disposed. The stretchable part has a given length that is operable to change in response to a force being applied to the device. The given length may, for example, elongate when the force causes the device to elongate. Alternative and/or additionally, the given length may compress when the force causes the device to compress.
Abstract:
Methods for optical restricting are described. An example of the invention relates to a method of restricting the brightness of a light source. The method can include: absorbing, in absorber material of a photo-restrictor, at least a portion of a primary emission produced by the light source; producing first photoexcitations in the absorber material characterized by a first excitation density; transferring the first photoexcitations from the absorber material to an emitter material of the photo-restrictor thereby producing second photoexcitations characterized by a second excitation density; and producing a secondary emission from the emitter material.
Abstract:
A stretchable photovoltaic device, a stretchable photovoltaic module and a carrier for facilitating formation of a stretchable photovoltaic device and/or module are provided. The stretchable photovoltaic device includes a stretchable part, at least one photovoltaic cell and a surface over which that at least one photovoltaic cell is disposed. The stretchable part has a given length that is operable to change in response to a force being applied to the device. The given length may, for example, elongate when the force causes the device to elongate. Alternative and/or additionally, the given length may compress when the force causes the device to compress.