Abstract:
Technologies are generally described for fabricating a self-writing waveguide. Two photo-reactive liquid monomers, each infused with a photo-initiator, may be mixed and dissolved in a carrier solvent to form a mixture. Nanoparticles may be added to the mixture to form a gel. A focused light beam may be provided to cure one of the monomers, initiating polymerization to form a core of the self-writing waveguide. An optional exposure to an optical source, a heat source, or an electron beam source may cure the other monomer, initiating polymerization to form a cladding of the self-writing waveguide. The self-writing waveguide may be formed in a substantially tubular structure or a planar film structure.
Abstract:
Technologies are generally described for composite membranes which may include a porous graphene layer in contact with a porous support substrate. In various examples, a surface of the porous support substrate may include at least one of: a thermo-formed polymer characterized by a glass transition temperature, a woven fibrous membrane, and/or a nonwoven fibrous membrane. Examples of the composite membranes permit the use of highly porous woven or nonwoven fibrous support membranes instead of intermediate porous membrane supports. In several examples, the composite membranes may include porous graphene layers directly laminated onto the fibrous membranes via the thermo-formed polymers. The described composite membranes may be useful for separations, for example, of gases, liquids and solutions.
Abstract:
Technologies are generally described for a membrane that may incorporate a graphene layer perforated by a plurality of nanoscale pores. The membrane may also include a gas sorbent that may be configured to contact a surface of the graphene layer. The gas sorbent may be configured to direct at least one gas adsorbed at the gas sorbent into the nanoscale pores. The nanoscale pores may have a diameter that selectively facilitates passage of a first gas compared to a second gas to separate the first gas from a fluid mixture of the two gases. The gas sorbent may increase the surface concentration of the first gas at the graphene layer. Such membranes may exhibit improved properties compared to conventional graphene and polymeric membranes for gas separations, e.g., greater selectivity, greater gas permeation rates, or the like.
Abstract:
Technologies are generally described for fabricating a self-writing waveguide. Two photo-reactive liquid monomers, each infused with a photo-initiator, may be mixed and dissolved in a carrier solvent to form a mixture. Nanoparticles may be added to the mixture to form a gel. A focused light beam may be provided to cure one of the monomers, initiating polymerization to form a core of the self-writing waveguide. An optional exposure to an optical source, a heat source, or an electron beam source may cure the other monomer, initiating polymerization to form a cladding of the self-writing waveguide. The self-writing waveguide may be formed in a substantially tubular structure or a planar film structure.
Abstract:
Technologies are generally described for a membrane that may incorporate a graphene layer perforated by a plurality of nanoscale pores. The membrane may also include a gas sorbent that may be configured to contact a surface of the graphene layer. The gas sorbent may be configured to direct at least one gas adsorbed at the gas sorbent into the nanoscale pores. The nanoscale pores may have a diameter that selectively facilitates passage of a first gas compared to a second gas to separate the first gas from a fluid mixture of the two gases. The gas sorbent may increase the surface concentration of the first gas at the graphene layer. Such membranes may exhibit improved properties compared to conventional graphene and polymeric membranes for gas separations, e.g., greater selectivity, greater gas permeation rates, or the like.
Abstract:
Technologies are generally described for a graphene membrane with uniformly-sized nanoscale pores that may be prepared at a desired size using colloidal lithography. A graphene monolayer may be coated with colloidal nanoparticles using self-assembly, followed by off-axis metal layer deposition, for example. The metal layer may form on the colloidal nanoparticles and on portions of the graphene not shadowed by the nanoparticles. The nanoparticles may be removed to leave a negative metal mask that exposes the underlying graphene through holes left by the removed nanospheres. The bare graphene may be etched to create pores using an oxygen plasma or similar material, while leaving metal-masked regions intact. Pore size may be controlled according to size of colloidal nanoparticles and angle of metal deposition relative to the substrate. The process may result in a dense, hexagonally packed array of uniform holes in graphene for use as a membrane, especially in liquid separations.
Abstract:
Technologies are generally described for composite membranes which may include a porous graphene layer in contact with a porous support substrate. In various examples, a surface of the porous support substrate may include at least one of: a thermo-formed polymer characterized by a glass transition temperature, a woven fibrous membrane, and/or a nonwoven fibrous membrane. Examples of the composite membranes permit the use of highly porous woven or nonwoven fibrous support membranes instead of intermediate porous membrane supports. In several examples, the composite membranes may include porous graphene layers directly laminated onto the fibrous membranes via the thermo-formed polymers. The described composite membranes may be useful for separations, for example, of gases, liquids and solutions.
Abstract:
Technologies are generally described for gas filtration and detection devices. Example devices may include a graphene membrane and a sensing device. The graphene membrane may be perforated with a plurality of discrete pores having a size-selective to enable one or more molecules to pass through the pores. A sensing device may be attached to a supporting permeable substrate and coupled with the graphene membrane. A fluid mixture including two or more molecules may be exposed to the graphene membrane. Molecules having a smaller diameter than the discrete pores may be directed through the graphene pores, and may be detected by the sensing device. Molecules having a larger size than the discrete pores may be prevented from crossing the graphene membrane. The sensing device may be configured to identify a presence of a selected molecule within the mixture without interference from contaminating factors.
Abstract:
An antenna relay system for facilitating wireless communication between mobile terminals on a high-speed rail vehicle and stationary base stations with substantially reduced Doppler shift effects comprises matched traveling wave directional antennas mounted to a high-speed rail vehicle and positioned collinearly alongside the railway. Both antennas continually transmit and receive at a fixed angle relative to the motion of the train so as to circumvent the Doppler shift. The signal transmitted or received by the stationary antenna is conducted to a nearest node for communication with an access network.
Abstract:
Technologies are generally described for composite membranes that may include a nanoporous graphene layer sandwiched between a first selective membrane and a porous support substrate. The composite membranes may be formed by depositing the selective membrane on one side of the nanoporous graphene layer, while the other side of the nanoporous graphene layer may be supported at a nonporous support substrate. The nanoporous graphene layer may be removed with the selective membrane from the nonporous support substrate and contacted to the porous support substrate to form the composite membranes. By depositing the selective membrane on a flat surface, the nanoporous graphene on the nonporous support substrate, the selective membranes may be produced with reduced defect formation at thicknesses of as little as 0.1 μm or less. The described composite membranes may have increased permeance compared to thicker selective membranes, and structural strength greater than thin selective membranes alone.