US GOVERNMENT AS REPRESENTED BY THE SECRETARY OF ARMY Patent applications |
Patent application number | Title | Published |
20130063158 | MICROWAVE CAVITY WITH DIELECTRIC REGION AND METHOD THEREOF - A method and apparatus for obtaining dielectric constant and other measurements of a sample, comprising an open cavity resonator; a microwave energy generator for creating a resonating microwave in the open cavity resonator; a predetermined dielectric material having a high dielectric constant in the range of 2 to 100,000 substantially filling the region in which a microwave resonates; the dielectric material adapted to receive a sample for measurement of the dielectric properties of the sample; whereby during operation the resonating microwave beam is substantially immersed in the predetermined dielectric material such that the effective electrical spot size and beam cross-section along the cylindrical axis of the resonating microwave is reduced as a function of the inverse of the square root of the predetermined dielectric material dielectric constant. The dielectric constant or loss tangent of the sample may be determined based upon the change in the cavity's resonant frequency modes. | 03-14-2013 |
20110180733 | TERAHERTZ RADIATION DEVICE USING POLAR SEMICONDUCTOR MATERIALS AND METHOD OF GENERATING TERAHERTZ RADIATION - A method and device for generating terahertz radiation comprising a plurality of layers of polar crystal material operative to emit terahertz radiation; the plurality of layers comprising transport layers and divider layers, the plane of the layers being not parallel to the polar axis, the interface between the transport layers and divider layers forming boundaries at which the internal electric polarization terminates leading to charges accumulating at the boundaries, and creation of internal electric fields oriented along the polar axis; whereby when irradiated by a pulsed source of duration less than one picosecond, a time-varying and spatially nonuniform distribution of carriers is created in the growth direction of the polar crystal material thereby generating a first time-varying current due to diffusion of the carriers; the internal electric fields accelerating the carriers generated by the pulsed radiation source operating to produce a second time-varying current that is additive with the first time-varying current, thereby enhancing the generation of terahertz radiation. | 07-28-2011 |
20110068208 | FIBER TENSIONING DEVICE AND METHOD OF MAKING PRESTRESSED STRUCTURES - A process for forming a prestressed structure that includes: winding a plurality of fibers around a structure in order to compressively prestress the structure; wherein the winding is achieved by a fiber tensioning device that includes: a plurality of axles rotatably supported by the frame, each axle having a drum that engages the plurality of aligned fibers, each axle also having a sprocket; a chain for coupling each of the sprockets; a brake connected to the chain which opposes the motion of the chain thus increasing the tension in the plurality of aligned fibers that are in contact with said drums; and whereby the aligned fibers are wound onto the structure under increased tension thus imparting compressive pressure between the aligned fibers on to the wound structure. | 03-24-2011 |