Abstract: An inductor for high current applications includes a nonconductive, tubular form which defines a tube axis and has a cylindrical outer surface. The outer surface is formed with a groove that extends helically about the tube axis. The inductor further includes a coiled, conductive wire that is formed with a plurality of turns. The wire is wound around the outer surface of the form with at least a portion of the wire disposed in the groove. With this structure, the form maintains a predetermined separation between adjacent turns of the coil preventing deformation of the coiled wire by strong magnetic forces that are generated when relatively high electrical currents are passed through the wire.

Abstract: An electromagnetic gun and rotating pulsed network system that includes a gun barrel coupled to a gun mount coupled on a rotating platform on one deck of a naval ship. A pulse forming network which is cylindrical in shape provides pulsed energy to the electromagnetic gun and is rotatable within a cylindrical bulkhead located on a lower deck of the ship. The pulse forming network rotates in unison with the gun barrel on the same axis, allowing unbroken cables to couple the pulse forming network to the gun. The pulse forming network includes wedge-shaped capacitor modules that, when juxtaposed, collectively form a substantially cylindrical shape.

Abstract: The present embodiments provide methods and apparatuses for use in controlling and directing magnetically levitated vehicles. In some embodiments, a method propels or passes a vehicle along a guideway, magnetically levitates the vehicle as it travels along the guideway, and induces a magnetic drag on the vehicle as it travels along a portion of the guideway. The magnetic drag can be induced by passing the magnet proximate a plate of conductive material. The plate can be positioned on a first side of the vehicle to induce the magnetic drag resulting in a force on the vehicle in a direction toward the first side. The method can further induce the magnetic drag to guide the vehicle along a curve of the guideway, where the plate is positioned on an inward side of the curve such that the force directs the vehicle into the curve.

Abstract: Methods and apparatus are provided for radar systems using multiple pulses that are shorter than the expected range delay extent of the target to be imaged. In one implementation, a method for performing radar includes the steps of: transmitting a plurality of pulses, each pulse having a different center frequency and a time duration shorter than an expected range delay extent of a target, wherein a total bandwidth is defined by a bandwidth occupied by the plurality of pulses; receiving reflections of the plurality of pulses; and performing pulse compression on the received pulse reflections to generate a detection signal having a radar resolution approximately equivalent to the transmission and reception of a single pulse having the total bandwidth. In preferred form, the pulses comprise ultrawideband (UWB) pulses each occupying a sub-band of the overall system bandwidth.

Abstract: An image projection system comprises a laser source that generates a series of periodic pulses having substantially uniform energy content, a spatial light modulator, and a modulator driver synchronized with the laser pulses so that transition intervals of the modulator elements occur in an interpulse period between first and second states of the modulator elements. Because the pulses are substantially equal in energy, and the transitions of the modulator elements occur in interpulse intervals, the collective energy delivered to any pixel in the system described herein during the period of one frame is a direct function of the number of pulses, which can be accurately controlled in a digital manner.

Abstract: A laser device which may be used as an oscillator or amplifier comprising a chamber having a volume formed therein and a gain medium within the volume. The gain medium comprises solid-state elements containing active laser ion distributed within the volume. A cooling fluid flows about the solid-state elements and a semiconductor laser diode provides optical pump radiation into the volume of the laser chamber such that laser emission from the device passes through the gain medium and the fluid. The laser device provides the advantages of a solid-state gain medium laser (e.g., diode-pumping, high power density, etc), but enables operation at higher average power and beam quality than would be achievable from a pure solid-state medium.

Abstract: Capacitor based pulse forming networks and related methods are provided which require fewer inductors are that pulsed more frequently to provide a smaller, lower mass, and lower inductance pulse forming network having better pulse shaping characteristics than conventional pulse forming networks. In one implementation, the invention can be characterized as a capacitor based pulse forming network comprising a plurality of inductors adapted to be coupled to a load, a plurality of capacitor units, and a plurality of switches. Each switch couples a respective capacitor unit to a respective inductor, wherein multiple capacitor units are coupled to each inductor by separate switches. The plurality of switches are adapted to non-simultaneously discharge the multiple capacitor units to provide non-simultaneous pulses through a given inductor to the load and not through other inductors. The non-simultaneous pulses form at least a portion of an output pulse waveform to the load.

Abstract: A persistent archive of a collection of data objects comprises a self-describing, infrastructure-independent representation of a logical structure for the collection and a self-describing, infrastructure-independent representation of the data objects. The archive is persistent in that it may be instantiated at an indefinite point in time in the future regardless of the state of technology at that time. A knowledge-based persistent archive of a collection of data objects comprises the foregoing two elements but also a self-describing, infrastructure-independent representation of knowledge relevant to the collection.

Abstract: A method of data transmission according to one embodiment of the invention includes transmitting a plurality of bursts to transmit data, each burst occupying at least one of a plurality of frequency bands. Specifically, a bandwidth of at least one of the plurality of bursts is at least two percent of the center frequency of the burst. In one preferred embodiment, a bandwidth of at least one of the plurality of bursts is at least 100 MHz. In another preferred embodiment, each burst occupies at least one of the plurality of frequency bands, but less than all of the plurality of frequency bands.

Abstract: Methods of fabricating large size, high performance multilayer diffraction gratings having a thick substrate that take advantage of reactive ion etching during the fabrication process are provided herein. In one implementation, a method of making a multilayer diffraction grating comprises the steps of: providing a substrate having a thickness of at least 2.0 cm; applying a dielectric structure having a plurality of layers on the semiconductor substrate; depositing a photoresist; exposing the photoresist to a grating pattern; developing the photoresist to produce the grating pattern in the photoresist; and reactive ion etching to transfer the grating pattern to the dielectric structure. In preferred form, the substrate material of the grating is selected to have low electrical resistivity and high thermal conductivity.

Abstract: An apparatus for producing a stable, high pressure plasma column with long length, and high axial uniformity. Rotating a gas-filled tube about an horizontal axis creates a vortex with minimal, or no shear flow. Such a vortex provides a stable equilibrium for a central column of high temperature gas and plasma when, for a given rotation speed, the centrifugal force dominates over the gravitational force inside the smallest radial dimension of the containment envelope. For gas pressures sufficiently high that the particle mean free path is short compared with the thickness of the gas layer between the central plasma column and the wall, thermal transport across this sheath layer is small and its temperature is low. High pressure discharges inside a rotating envelope may be sustained by a variety of means, including electrical, electromagnetic and chemical; they may find application in plasma torches, light sources, etc.

Abstract: An electrolyzer for generating hydrogen by the electrolytic dissociation of water employs anode and cathode half-cells, separated by a planar polymer-based solid electrolyte, and includes a water reservoir for independently maintaining a desired level of water in the anode and cathode half-cells. A hydrogen exit chimney extends vertically upward from each cathode half-cell and enters a separation chamber; a gas exit passageway therefrom is closed by a separation membrane that allows the passage of H2 but rejects liquid H2O, while a return water passageway enters near the bottom of the cathode half-cell. The half-cells are preferably formed by molded plastic frames that are arranged as a cell stack containing a plurality of electrolytic cells, with flat metal anodes and cathodes being respectively sandwiched about the solid electrolyte membrane in each cell.

Abstract: A laser device which may be used as an oscillator or amplifier comprising a chamber having a volume formed therein and a gain medium within the volume. The gain medium comprises solid-state elements containing active laser ion distributed within the volume. A cooling fluid flows about the solid-state elements and a semiconductor laser diode provides optical pump radiation into the volume of the laser chamber such that laser emission from the device passes through the gain medium and the fluid. The laser device provides the advantages of a solid-state gain medium laser (e.g., diode-pumping, high power density, etc), but enables operation at higher average power and beam quality than would be achievable from a pure solid-state medium.

Abstract: Methods and apparatus are provided for radar systems using multiple pulses that are shorter than the expected range delay extent of the target to be imaged. In one implementation, a method for performing radar includes the steps of: transmitting a plurality of pulses, each pulse having a different center frequency and a time duration shorter than an expected range delay extent of a target, wherein a total bandwidth is defined by a bandwidth occupied by the plurality of pulses; receiving reflections of the plurality of pulses; and performing pulse compression on the received pulse reflections to generate a detection signal having a radar resolution approximately equivalent to the transmission and reception of a single pulse having the total bandwidth. In preferred form, the pulses comprise ultrawideband (UWB) pulses each occupying a sub-band of the overall system bandwidth.

Abstract: A polling method, apparatus, and system capable to detect the attachment and detachment of Universal Serial Bus (USB) devices in a wireless USB system. A USB hub provides a wired connection to the host, while providing wireless attachment points for its devices. The USB host periodically queries the hub looking for changes in the hub's status register. During each period, the hub sends a polling message through each of its wireless ports, and awaits a response. A peripheral device that wishes to attach to the system responds to the message by sending its unique peripheral address. If a device currently occupies the port, the hub sends out the device's unique assigned address as part of the polling message. If the device is still present, it responds by sending its unique peripheral address. If the host does not receive a response after multiple retries, the device is considered detached.

Abstract: Capacitor based pulse forming networks and related methods are provided which require fewer inductors are that pulsed more frequently to provide a smaller, lower mass, and lower inductance pulse forming network having better pulse shaping characteristics than conventional pulse forming networks. In one implementation, the invention can be characterized as a capacitor based pulse forming network comprising a plurality of inductors adapted to be coupled to a load, a plurality of capacitor units, and a plurality of switches. Each switch couples a respective capacitor unit to a respective inductor, wherein multiple capacitor units are coupled to each inductor by separate switches. The plurality of switches are adapted to non-simultaneously discharge the multiple capacitor units to provide non-simultaneous pulses through a given inductor to the load and not through other inductors. The non-simultaneous pulses form at least a portion of an output pulse waveform to the load.

Abstract: An electromagnetic gun and rotating pulsed network system that includes a gun barrel coupled to a gun mount coupled on a rotating platform on one deck of a naval ship. A pulse forming network which is generally cylindrical in shape provides pulsed energy to the electromagnetic gun and is rotatable within a cylindrical bulkhead located on a lower deck of the ship. The pulse forming network rotates in unison with the gun barrel on the same axis, allowing unbroken cables to couple the pulse forming network to the gun. The pulse forming network includes wedge-shaped capacitor modules that, when juxtaposed, collectively form a substantially annular shape having generally cylindrical inner and outer surfaces.

Abstract: A method for simulating a compressible fluid includes selecting an equilibrium distribution function for simulating a fluid; receiving as input an initial value of at least one variable of a distribution function having for at least two time steps; setting the distribution function equal to the equilibrium distribution function; deriving an advected distribution function from the distribution function evaluated at the at least two time steps; calculating a current value of the at least one variable from the advected distribution function; and generating as output the current value of the at least one variable. The simulation of a fluid in accordance with the present invention has inherent positive hyperviscosity and hyperdiffusivity for very small values of viscosity and thermal diffusivity, and short wavelength modes are shown to be stable for temperatures above a lower limit. Finite amplitude sound waves are shown to steepen as expected from gas dynamic theory.

Abstract: Systems are described that disperse the wavelength bands corresponding to the channel centers at a faster rate than the bandwidth of the channels themselves. An embodiment consists of a double element system including a grating, to create the initial separation, and a segmented mirror with multiple flat facets of different tilt, which reflect each spatially separated channel at a different angle. The size, position and angle of the facets are designed to match the spacing and position of individual channels of known wavelength and number that are diffracting from a grating with a predefined period, a set distance from this device. This system enables the individual channels to be re-imaged at some later point with a large separation between the channels, relative to their spatial size.

Abstract: A polling method, apparatus, and system to detect the attachment and detachment of Universal Serial Bus devices in a wireless system. A hub provides a wired connection to the host and wireless attachment points for its devices. The host periodically queries the hub for changes in the hub's status register by sending a polling message through each of its wireless ports, and awaits a response. A peripheral device that wishes to attach to the system responds by sending its unique peripheral address. If a device currently occupies the port, the hub sends out the device's unique address in the polling message. If the device is still present, it responds by sending its unique peripheral address. If a response is not received after multiple retries, the device is considered detached. The hub thus determines the status of the ports and updates the status register, which is queried by the host.