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 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: 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 perforated graphene monolayers and membranes containing perforated graphene monolayers. An example membrane may include a graphene monolayer having a plurality of discrete pores that may be chemically perforated into the graphene monolayer. The discrete pores may be of substantially uniform pore size. The pore size may be characterized by one or more carbon vacancy defects in the graphene monolayer. The graphene monolayer may have substantially uniform pore sizes throughout. In some examples, the membrane may include a permeable substrate that contacts the graphene monolayer and which may support the graphene monolayer. Such perforated graphene monolayers, and membranes comprising such perforated graphene monolayers may exhibit improved properties compared to conventional polymeric membranes for gas separations, e.g., greater selectivity, greater gas permeation rates, or the like.

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: Arrayed imaging systems include an array of detectors formed with a common base and a first array of layered optical elements, each one of the layered optical elements being optically connected with a detector in the array of detectors.

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 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: 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 described herein are generally related to systems and processes for repairing a graphene membrane on a support. A chamber may receive a layer of graphene on a support. The layer of graphene may include a hole. A first container including an initiator may be effective to apply an initiator through the hole to the support to functionalize the support and produce an initiator layer on the support. A second container including an activator may be effective to apply an activator through the hole to the initiator layer to activate the initiator layer. The application of the activator may further be effective to grow a polymer from the initiator layer. The growth of the polymer may be effective to produce a polymer plug in the hole and effective to repair at least a portion of the layer of graphene.

Abstract: Technologies described herein are generally related to repairing graphene on a porous support. In some examples, a method is described that may include receiving a graphene layer on a support. The graphene layer may include a hole and a pore. The method may further include applying a first reactive material to a first side of the graphene layer. The first reactive material may include molecules larger than the pore. A second reactive material may be applied through the support to a second side of the graphene layer. The second reactive material may include molecules larger than the pore. The first and second reactive materials may react in the hole to produce a plug in the hole and to repair the graphene layer.

Abstract: Technologies are generally described for perforated graphene monolayers and membranes containing perforated graphene monolayers. An example membrane may include a graphene monolayer having a plurality of discrete pores that may be chemically perforated into the graphene monolayer. The discrete pores may be of substantially uniform pore size. The pore size may be characterized by one or more carbon vacancy defects in the graphene monolayer. The graphene monolayer may have substantially uniform pore sizes throughout. In some examples, the membrane may include a permeable substrate that contacts the graphene monolayer and which may support the graphene monolayer. Such perforated graphene monolayers, and membranes comprising such perforated graphene monolayers may exhibit improved properties compared to conventional polymeric membranes for gas separations, e.g., greater selectivity, greater gas permeation rates, or the like.

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: A detector assembly is configured for characterizing electromagnetic energy that propagates along a light path. At least a component of the electromagnetic energy carries electromagnetic energy information along the light path. The detector assembly includes a first detector array arranged along the light path and having photosensitive elements aligned to receive at least some of the electromagnetic energy, including the component. The photosensitive elements selectively absorb a first portion of the component and produce a first set of electrical image data, based at least in part on the electomagnetic energy information, in response to the component. At least some of the photosensitive elements are at least partially transparent so that they selectively pass a second portion of the component to continue along the light path.

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: A detector assembly is configured for characterizing electromagnetic energy that propagates along a light path. At least a component of the electromagnetic energy carries electromagnetic energy information along the light path. The detector assembly includes a first detector array arranged along the light path and having photosensitive elements aligned to receive at least some of the electromagnetic energy, including the component. The photosensitive elements selectively absorb a first portion of the component and produce a first set of electrical image data, based at least in part on the electomagnetic energy information, in response to the component. At least some of the photosensitive elements are at least partially transparent so that they selectively pass a second portion of the component to continue along the light path.

Abstract: Arrayed imaging systems include an array of detectors formed with a common base and a first array of layered optical elements, each one of the layered optical elements being optically connected with a detector in the array of detectors.

Abstract: Fiber Bragg grating coupled light sources can achieve tunable single-frequency (single axial and lateral spatial mode) operation by correcting for a quadratic phase variation in the lateral dimension using an aperture stop. The output of a quasi-monochromatic light source such as a Fabry Perot laser diode is astigmatic. As a consequence of the astigmatism, coupling geometries that accommodate the transverse numerical aperture of the laser are defocused in the lateral dimension, even for apsherical optics. The mismatch produces the quadratic phase variation in the feedback along the lateral axis at the facet of the laser that excites lateral modes of higher order than the TM00. Because the instability entails excitation of higher order lateral submodes, single frequency operation also is accomplished by using fiber Bragg gratings whose bandwidth is narrower than the submode spacing. This technique is particularly pertinent to the use of lensed fiber gratings in lieu of discrete coupling optics.