Patents

William C. Moss
Thermoacoustic Refrigerator
U.S. Patent 5,673,561
October 7, 1997
A thermoacoustic device having a thermal stack made from a piece of porous material, which provides a desirable ratio of thermoacoustic area to viscous area. The material has a low resistance to flow to minimize acoustic streaming, high specific heat conductivity, and low thermal conductivity. The inexpensive thermal stack can be formed of reticulated vitreous carbon and is easily formed in small sizes. A heat exchanger of heat-conductive, open-cell foam may be included. The thermoacoustic cooling device may be combined with a semiconductor device.

Anthony M. McCarthy
Silicon on Insulator Achieved Using Electrochemical Etching
U.S. Patent 5,674,758
October 7, 1997
A manufacturing process for forming thin-film crystalline silicon circuits on arbitrary supports. The process includes four basic stages: preparation, bonding, thinning, and silicon region formation. The process takes silicon wafers with completed circuits, bonds the circuit side of the wafer to the support, and thins the wafer to remove excess silicon. Electrochemically enhanced etching is then used to define the circuits and expose the electrical contact regions. This process provides an economical thin-film silicon-on-insulator technique for microelectronics fabrication applications.


Kathleen I. Schaffers , Laura D. DeLoach , Stephen A. Payne , and Douglas A. Keszler
Ytterbium-Doped Borate Fluoride Laser Crystals and Lasers
U.S. Patent 5,677,921
October 14, 1997
Ytterbium-doped borate fluoride host crystals, having a formula of MM'(BO3)F, where M, M' are monovalent, divalent, and trivalent metal cations. The crystals can be used in laser oscillation and amplifiers. A particular composition is Yb-doped BaCaBO3F (Yb:BCBF). Because BCBF and some related derivative crystals are capable of nonlinear frequency conversion, whereby the fundamental of the laser is converted to a longer or shorter wavelength, these new crystals can simultaneously serve as self-frequency doubling crystals and laser materials within a laser resonator.


Roger D. Aines and Robin L. Newmark
Active Cooling-Based Surface Confinement System for Thermal Soil Treatment
U.S. Patent 5,681,130
October 28, 1997
A process for the use of a thermal barrier to control the ground subsurface pressure by active cooling. This barrier is placed in contact with the ground surface, and a region underneath the barrier is heated for remediation. The cooling capacity of the barrier is controlled so that rising gases and vapors in the soil are condensed and confined beneath the barrier. The subsurface pressure is thereby controlled by controlling the surface temperature. This method is useful for thermal remediation involving steam injection. The thermal barrier prevents steam breakthrough during thermal remediation of shallow underground contaminants.


Thomas E. McEwan
Pulse Homodyne Field Disturbance Sensor
U.S. Patent 5,682,164
October 28, 1997
An inexpensive field-disturbance sensor that transmits a sequence of transmitted bursts of electromagnetic energy. The transmitter frequency is modulated at an intermediate frequency. The sequence of bursts has a burst repetition rate, and each burst has a burst width and comprises a number of cycles at a transmitter frequency. The sensor includes a receiver that receives electromagnetic energy at the transmitter frequency and a mixer that mixes a transmitted burst with reflections of the same transmitted burst to produce an intermediate-frequency signal. A second range-defining mode transmits two radiofrequency bursts, where the time spacing between the bursts defines the maximum range divided by two.





Awards

Richard W. (Dick) Lee and Max Tabak have been elected Fellows of the American Physical Society for their outstanding contributions to physics. Among the 179 fellows elected in 1997, they are both members of the society's Plasma Physics Division. Lee, a senior scientist in the Physics and Space Technology Directorate office, was recognized "for technical contributions and outstanding outreach of codes for plasma spectroscopy." A physicist and group leader for inertial confinement fusion in the Defense and Nuclear Technolgoies Directorate, Tabak was cited for "his exceptional inventive and broad contributions to the fields of laser and particle-driven inertial fusion, and in particular for being the principal inventor of the fast ignition concept."
IndustryWeek magazine selected Charles Alcock as one of the nation's top 50 R&D "stars" for his research on dark matter, known as MACHOS (Massive Compact Halo Objects).
Kennedy Reed, named the winner of the International Center for Theoretical Physics Visiting Scholar Award, traveled to the University of Dakar in Senegal and the University of Cape Coast in Ghana to fulfill duties of the award, which included consulting and leading seminars.
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