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April 2001

The Laboratory
in the News

Commentary by Bert Weinstein

A New Kind
of Biological

The World's Most Accurate Lathe

Leading the
Attack on Cancer

Electronic Memory Goes High Rise




Abraham P. Lee, Asuncion V. Lemoff
Micromachined Magnetohydrodynamic Actuators and Sensors
U.S. Patent 6,146,103
November 14, 2000
A magnetohydrodynamic (MHD) micropump and microsensor that uses micromachining to integrate the electrodes with microchannels and includes a magnet for producing magnetic fields perpendicular to both the electrical current direction and the fluid flow direction. The magnet can also be micromachined and integrated with the micropump using existing technology. The MHD micropump, for example, can generate continuous, reversible flow, with readily controllable flow rates. The flow can be reversed by either reversing the electrical current flow or reversing the magnetic field. By mismatching the electrodes, a swirling vortex flow can be generated for potential mixing applications. No moving parts are necessary, and the dead volume is minimal. The micropumps can be placed at any position in fluidic circuit, and a combination of micropumps can generate fluidic plugs and valves.

James G. Berryman, William D. Daily, Abelardo L. Ramirez, Jeffery J. Roberts
Using Electrical Impedance Tomography to Map Subsurface Hydraulic Conductivity
U.S. Patent 6,147,497 November 14, 2000 Electrical impedance tomography (EIT) can be used to map hydraulic conductivity in the subsurface where measurements of both amplitude and phase are made. Hydraulic conductivity depends on at least two parameters: porosity and a length-scale parameter. Electrical resistance tomography (ERT) measures and maps electrical conductivity (which can be related to porosity) in three dimensions. The desired additional measurement of a pertinent length scale can be achieved by introducing phase measurements along with amplitude. Hydraulic conductivity controls the ability to flush unwanted fluid contaminants from the surface. Thus, inexpensive maps of hydraulic conductivity would improve planning strategies for subsequent remediation efforts. Fluid permeability is also of importance for oil-field exploitation, and thus, detailed knowledge of fluid permeability distribution in three dimensions would be a useful to petroleum reservoir analysts.

Layton C. Hale, Terry Malsbury, Russell M. Hudyma, John M. Parker
Projection Optics Box
U.S. Patent 6,147,818
November 14, 2000
A projection optics box or assembly for use in an optical assembly, such as in an extreme ultraviolet lithography (EUVL) system using 10- to 14-nanometer soft x-ray photons. The box uses numerous highly reflective optics or mirrors. Each is mounted on a precision actuator, and each reflects an optical image, such as from a mask, in the EUVL system onto a point of use, such as a target or silicon wafer. The mask would have received an optical signal from a source assembly via a series of the EUVL systemÕs highly reflective mirrors. Most of the highly reflective optics or mirrors are mounted in a housing assembly comprising a series of bulkheads whose walls have been secured together for maximum rigidity. Because of the precision actuators, the mirrors must be positioned precisely and remotely in tip, tilt, and piston (three degrees of freedom), while also providing exact constraint.

Daniel M. Makowiecki, John A. Kerns, Craig S. Alford, Mark A. McKernan
Apparatus for Coating Powders
U.S. Patent 6,149,785
November 21, 2000
A process and apparatus for coating small particles and fibers. The process involves agitating the particles or fibers to promote uniform coating, removing adsorbed gases and static charges from the particles or fibers by an initial plasma cleaning, and coating the particles or fibers with one or more coatings. A first coating is an adhesion coating, and subsequent coatings are deposited in situ to prevent contamination at layer interfaces. The first coating is of an adhesion-forming element (tungsten, zirconium, rhenium, chromium, titanium) that is 10 to 10,000 nanometers thick. The second or final coating is composed of multiple materials from 0.1 to 10 micrometers thick, which could be, for example, of copper or silver for brazing processes or of other desired materials that define the new surface-related properties of the particles. An essential feature of the coating process is the capability to deposit in situ without interruption so that a contaminated interface that could adversely affect the coating adhesion is not formed. The process may include screening of the material to be coated and either continuous or intermittent vibration to prevent agglomeration of the material to be coated.

Stephen P. Vernons
Defect-Tolerant Transmission Lithography Mask
U.S. Patent 6,150,060
November 21, 2000
A transmission lithography mask that uses a transparent substrate or a partially transparent membrane as the active region of the mask. A reflective single-layer or multilayer coating is deposited on the membrane surface facing the illumination system. The coating is selectively patterned (removed) to form transmissive (bright) regions. Structural imperfections and defects in the coating have a negligible effect on the aerial image of the mask master pattern because the coating is used to reflect radiation out of the entrance pupil of the imaging system. Similarly, structural imperfections in the clear regions of the membrane have little influence on the amplitude or phase of the transmitted electromagnetic fields. Because the mask discards, rather than absorbs, unwanted radiation, it has reduced optical absorption and reduced thermal loading compared with those in conventional designs. For extreme ultraviolet applications, the mask circumvents the phase defect problem and is independent of the thermal loading during exposure.

Michael D. Perry, Brent C. Stuart, Paul S. Banks, Booth R. Myers, Joseph A. Sefcik
Laser Machining of Explosives
U.S. Patent 6,150,630
November 21, 2000
The invention consists of a method for machining (cutting, drilling, sculpting) explosives. By using laser pulses of a duration from 5 femtoseconds to 50 picoseconds, extremely precise and rapid machining can be achieved with essentially no heat or shock effects. The material is in essence converted from its initial solid state directly into a fully ionized plasma on a time scale too short for thermal equilibrium to be established with the lattice. As a result, heat conduction beyond the region removed is negligible, resulting in a negligible thermal stress or shock to the material beyond a few micrometers from the laser-machined surface. Hydrodynamic expansion of the plasma eliminates the need for any ancillary techniques to remove material and produces extremely high-quality machined surfaces. The explosive does not detonate or deflagrate in the process, and the material that is removed is rendered inert.

James C. Davidson, Joseph W. Balch
Extended-Length Microchannels for High-Density, High-Throughput Electrophoresis Systems
U.S. Patent 6,153,076
November 28, 2000
High-throughput electrophoresis systems that provide extended well-to-read distances on smaller substrates, thus compacting the overall systems. The electrophoresis systems use a high-density array of microchannels for electrophoresis analysis with extended read lengths. The microchannel geometry can be used individually or in conjunction with others to increase the effective length of a separation channel while minimally affecting the packing density of channels. One embodiment uses sinusoidal microchannels while another embodiment uses plural microchannels interconnected by a via. The extended channel systems can be applied to virtually any type of channel-confined chromatography.

Alan F. Jankowski, Anthony P. Schmid
Titanium–Chromium–Aluminum–Oxygen Thin-Film Resistors
U.S. Patent 6,154,119
November 28, 2000
Thin films of titanium–chromium–aluminum–oxygen (Ti–Cr–Al–O) are used as a resistor material. The films are radiofrequency-sputter-deposited from ceramic targets using a reactive working gas mixture of argon and oxygen. Resistivity values from 10 thousand to 10 million ohm-centimeters have been measured for Ti–Cr–Al–O film less than 1 micrometer thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti–Cr–Al–O as a thin-film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti–Cr–Al–O film can be used as a vertical or lateral resistor (for example, as a layer beneath a field-emission cathode in a flat-panel display) or as a means of controlling surface emissivity (for example, as a coating on an insulating material such as vertical wall supports in flat-panel displays).

Raymond P. Mariella, Jr.
Waveguide Detection of Right-Angle-Scattered Light in Flow Cytometry
U.S Patent 6,154,276
November 28, 2000
A transparent flow cell is used as an index-guided optical waveguide. A detector for the flow cell (but not for the liquid stream) detects the right-angle-scattered (RAS) light exiting from one end of the flow cell. The detector(s) could view the trapped RAS light from the flow cell either directly or through intermediate optical light guides. If the light exits one end of the flow cell, then the other end of the flow cell can be given a high-reflectivity coating to approximately double the amount of light collected. This system is more robust in its alignment than the traditional flow-cytometry systems that use imaging optics, such as microscope objectives.

John F. Poco, Lawrence W. Hrubesh
Method of Producing Optical-Quality Glass Having a Selected Refractive Index
U.S. Patent 6,158,244 December 12, 2000 Optical-quality glass having a selected refractive index is produced by a two-stage drying process. A gel is produced using sol-gel chemistry techniques and first dried by controlled evaporation until the gel volume reaches a preselected value. The preselected volume determines the density and refractive index of the finally dried gel. The gel is refilled with solvent in a saturated vapor environment and then dried again by supercritical extraction of the solvent to form a glass. The glass has a refractive index less than that of the full density of glass. The range of achievable refractive indexes depends on the composition of the glass. Glasses having different refractive indexes chosen from an uninterrupted range of values can be produced from a single precursor solution.

Raymond J. Beach, Eric C. Honea, Camille Bibeau, Scott Mitchell, John Lang, Dennis Maderas, Joel Speth, Stephen A. Payne
Hollow Lensing Duct
U.S. Patent 6,160,934
December 12, 2000
A hollow-lensing-duct method of condensing (intensifying) light that combines focusing using a spherical or cylindrical lens followed by reflective waveguiding. The hollow duct tapers down from a wide input side to a narrow output side, with the input side consisting of a lens that may be coated with an antireflective coating for more efficient transmission into the duct. The inside surfaces of the hollow lens duct are appropriately coated to be reflective, preventing light from escaping by reflection as it travels along the duct (reflective waveguiding). The hollow duct has various applications for intensifying light, such as in the coupling of diode-array-pumped light to solid-state lasing materials.

M. Leslie Carman, Robert T. Taylor
In Situ Microbial Filter Used for Bioremediation
U.S. Patent 6,165,356
December 26, 2000
An improved method for in situ microbial filter bioremediation that increases the operational longevity of an in situ microbial filter emplaced into an aquifer. A method for generating a microbial filter of sufficient catalytic density and thickness, which has an increased replenishment interval, improved bacteria attachment and detachment characteristics, and endogenous stability under in situ conditions. A system for in situ water remediation.

Stefan P. Swierkowski
Integrated Titer Plate-Injector Head for Microdrop Array Preparation, Storage, and Transfer
U.S. Patent 6,165,417
December 26, 2000
An integrated titer plate-injector head for preparing and storing two-dimensional (2D) arrays of microdrops and for ejecting some or all of the microdrops and inserting them into 2D arrays of deposition sites with micrometer precision. The titer plate-injector head includes integrated precision-formed nozzles with appropriate hydrophobic surface features and evaporative constraints. A reusable pressure head with a pressure equalizing feature is added to the titer plate to perform simultaneous precision sample ejection. The titer plate-injector head may be used in various applications, including capillary electrophoresis, chemical flow injection analysis, and microsample array preparation.

Ralph H. Page, Raymond J. Beach
Thermal Lens Elimination by Gradient-Reduced Zone Coupling of Optical Beams
U.S. Patent 6,167,069
December 26, 2000
A thermal-gradient-reduced zone laser that includes a laser medium and an optically transparent plate with an index of refraction that is less than the index of refraction of the laser medium. The pump face of the laser medium is bonded to a surface of the optically transparent member. Pump light is directed through the transparent plate to optically pump the solid-state laser medium. Heat conduction is mainly through the surface of the laser medium, where the heat is introduced by the pump light. Heat flows in a direction opposite that of the pump light because the side of the laser medium that is opposite the pump face is not in thermal contact with a conductor; thus, there is no heat flux (and no temperature gradient), and a thermal-gradient-reduced zone is produced. A laser cavity is formed around the laser medium such that laser light oscillating within the laser cavity reflects by total internal reflection from the interface between the pump face and the optically transparent plate and enters and exits through a thermal-gradient-reduced zone.

John F. Poco, Lawrence W. Hrubesh
Method of Casting Patterned Dielectric Structures
U.S. Patent 6,168,737
B1 January 2, 2001
A pattern of dielectric structures is formed directly on a substrate in a single step using sol-gel chemistry and molding procedures. The resulting dielectric structures are useful in vacuum applications for electronic devices. Porous, lightweight structures having a high aspect ratio that are suitable for use as spacers between the faceplate and baseplate of a field emission display can be manufactured using this method.




































































































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