Abstract: The thawing time of frozen block food is shortened by subjecting the frozen food to low power sound energy having a frequency in the relaxation frequency spectrum of the ice crystals in the frozen food and having a sound pressure level in the range of about 150-300 dB.

Abstract: A mirror antenna employing a continuous mirror without a hole. A feed horn nd an electromagnetic lens, located behind a rotatable twist reflector (the mirror), collimates a beam toward a polarized reflector located near the twist reflector and tilted to aim energy toward the twist reflector. Energy reflected back toward the polarized reflector from the twist reflector passes through the polarized reflector to free space.

Abstract: An apparatus for training students in thermal image recognition provides a lurality of variable thermal images for viewing through telescopic sights at a plurality of student stations. Identification of the image is electronically evaluated for correctness and response time by a microcomputer, located at an instructor station, which controls displays indicative of the student's performance.

Abstract: A drill guide device for bone plate fixation, consisting of an elongated drill guide block having a longitudinal recess for receiving and positioning a bone plate having screw openings. The guide block has spaced openings axially aligned with the bone plate screw openings and containing removable drill guide bushings. The guide block is longitudinally slotted at its ends for adjustable attachment to clamp blocks carrying respective bone-engaging scissor clamp assemblies connected by tie rods. The tie rods have oppositely threaded ends which are threadedly engaged with the respective clamp blocks. The tie rods have hexagonal center portions shaped for driving engagement by a wrench. The scissor clamp assemblies have upstanding opposite top handle portions connected by clamping screws, each clamping screw being pivotally connected to one handle portion and extending through the opposite handle portion. The outer end portion of each clamping screw is provided with a clamping nut.

Abstract: A shielding apparatus is provided for containing frozen bags of fluid and re particularly for containing frozen bags of blood components during microwave thaw. The apparatus includes a metal box for receiving a blood bag, the box having a bottom and sides. A metallic lid is provided, and a hinging device pivotally mounts the lid to the box for enclosing the blood bag therein. The lid and optionally the bottom of the box may be provided with an aperture for allowing microwaves to enter the box. Radiation absorbing strips are mounted along the edges of the apertures for absorbing E field reflections toward the blood bag. The apertures allow microwave energy to be concentrated in the more voluminous part of the blood bag while the edges of bag as well as any tubing are shielded by the metallic box. This apparatus prevents boiling of the blood in the lower volume areas of the bag.

Abstract: A feed element-to-beam interconnection network is provided for an antenna that transmits and receives a large number of beams, such as 87 contiguous narrow beams that cover the United States. The network, which is connected to a layer of 134 feed elements that transmit and receive microwaves, consists of a pair of circuit boards (160c, 162c in FIG. 7) parallel to the feed element layer. One of the two boards has 87 dividers (e.g. 51td, FIG. 5) that each divide a signal to be transmitted into seven portions, and the other board has 134 combiners (e.g. 38tc) that each collect seven transmit signal portions and deliver the sum to one of the feed elements. A similar arrangement is used to handle received signals, with 134 receive signal dividers (e.g. 38rd) on the one board, and 87 receive signal combiners (e.g. 51rc) on the other board.

Abstract: The sodium content of a food is reduced and the potassium content simultaneously increased by a process wherein an aqueous solution of a sodium-containing food and an aqueous solution containing potassium ions are circulated on opposite sides of a cation exchange membrane for a time and at a rate sufficient to exchange at least a portion of the sodium and potassium ions.

Abstract: A superlattice semiconductor device consisting of a plurality of multi-dimensional charge carrier confinement regions of semiconductor material exhibiting relatively high charge carrier mobility and a low band gap which are laterally located in a single planar layer of semiconductor material exhibiting a relatively low charge carrier mobility and high band gap and wherein the confinement regions have sizes and mutual separation substantially equal to or less than the appropriate deBroglie wavelength. The device, in its preferred form, comprises a thin film of semiconductor material selected from group II-VI or III-V compounds or silicon wherein there is formed laterally located cylindrically shaped periodic regions which are adapted to act as quantum well confinement regions for electrons.

Abstract: A bandpass filter is comprised by a plurality of reflection gratings operating in a Wood's anomaly region and arranged in serial relationship. Specifically, the gratings are serially arranged in two substantially parallel rows with the gratings in the first row offset laterally from the gratings in the second row. Further, the input to each grating is at substantially the same angle of incidence such that the output of one grating is the direct input to the next succeeding one of the gratings.

Abstract: A controlled absorption path filter for charge couple device seekers is made using a variable depth fluid. The use of a liquid as an absorber permits the entire aperture area to darken without loss of aperture. Thus the device provides a uniform extinction feature which preserves the system modulation transfer function. The device can be tied to a closed loop system with automatic gain control for feedback. Depending on the nature of absorber in the liquid, the device can also serve as a spectral filter. The device is applicable for visible light to near infrared light.

Abstract: Improved spherules for making enhanced forms of nuclear-reactor fuels are prepared by internal gelation procedures within a sol-gel operation and are accomplished by first boiling the concentrated HMTA-urea feed solution before engaging in the spherule-forming operation thereby effectively controlling crystallite size in the product spherules.

Abstract: Fluid pressure mechanism for locking a movable rod or similar member in scted positions of adjustment. The mechanism includes a fluid housing having at least one annular rod-gripper element encircling a movable rod. Introduction of fluid pressure into the housing causes the gripper element to expand out of locking engagement with the rod. Removal of the fluid pressure force enables the gripper element to relax into locking engagement with the rod. In a preferred arrangement two rod-gripper elements are employed. The rod passes through the two gripper elements located in opposite side walls of the housing.

Abstract: A novel explosive compound, 1,4,5,8-tetranitro-1,4,5,8-tetraazadifurazano[3,4-c][3,4-h]decalin is prepared by the reaction of 3,4-diaminofurazan and glyoxal in dilute hydrochloric acid, followed by the nitration of the intermediate 1,4,5,8-tetraazadifurazano[3,4-c][3,4-h]decalin. The nitrated compound has a higher density and detonation pressure and velocity than the known explosives HMX and HNB.

Abstract: A method of fabricating an acoustic wave resonator wherein all processing steps are accomplished from a single side of said substrate. The method involves deposition of a multi-layered Al/AlN structure on a GaAs substrate followed by a series of fabrication steps to define a resonator from said composite. The resulting resonator comprises an AlN layer between two Al layers and another layer of AlN on an exterior of one of said Al layers.

Abstract: A soluble polyene polymer and a method of making the same are disclosed. The polymer is of the class suitable for doping to produce an electrically conductive polymer. The method is generally applicable to acetylenic and aromatic monomers, proven examples of which include acetylene, benzene, anthracene and napthalene. In accordance with the method, the monomer is dissolved in arsenic trifluoride. Arsenic pentafluoride is then introduced into the solution to induce polymerization by what is speculated to be an ionic polymerization reaction. The resulting polymer differs from other polyene polymers in that it is soluble in common organic solvents, and further in that it can be melted without undergoing decomposition, thereby rendering it particularly suitable for processing to form various polymeric articles.

Abstract: A method of molding a red phosphorous pyrotechnic mix containing an epoxy nder, which is markedly improved by the addition of silica.

Abstract: An inside collet assembly for positioning an IMPATT diode precisely axially long and coaxially of a cylindrical cavity. The assembly serves for convenient removal and repositioning of the diode within the cavity and provides effective electrical and thermal connection to the diode. The assembly is not significantly larger in diameter than the cavity and does not require surfaces producing undesired reflections of microwaves within the cavity.

Abstract: The optical injection-locking of an FET oscillator is accomplished by injecting the beat signal between two coherently mixed slave lasers, which are locked to different harmonics of a modulated master laser, into the FET oscillator to be locked. 120 GHz injection-locking beat signals are possible using this technique.

Abstract: A constant false alarm rate is achieved in a moving-target-indicator radar y controlling the threshold in doppler channels according to the level of clutter in range gates near the range rate being examined for the presence of a target. Processing is simplified by using analog signals in charge coupled devices for target detection.

Abstract: In an intercom system, electrical noise interference is alleviated by interconnecting the tranceivers and receivers with the control sets via fibre optic lines. Audio signals are applied to a multiplexer which drives an optical modulator. The output of the optical modulator feeds a fiber optic line. Conversely, optical signals are fed to an optical demodulator whose output feeds a demultiplexer. Audio outputs from the demultiplexers feed the receivers and tranceivers and control sets.