William P. Chandler, Christine L. Hartmann-Siantar, and James A. Rathkopf
Calculation of Radiation Therapy Dose Using All Particle Monte Carlo Transport
U.S. Patent 5,870,697
February 9, 1999
A means of calculating the actual radiation dose absorbed in the body using the three-dimensional Monte Carlo transport method. Neutrons, protons, deuterons, tritons, helium-3, alpha particles, photons, electrons, and positrons are transported in a completely coupled manner, using this Monte Carlo all-particle transport method. The major elements include computer hardware, radiation source description, physical databases, Monte Carlo transport method, and output of dose distributions. Dose distributions are estimated for neutrons, photons, electrons, positrons, and heavy charged particles incident on any biological target, with resolutions ranging from micrometers to centimeters. Calculations can be extended to general-geometry (non-Cartesian) grids for other media.
David J. Erskine
Noise Pair Velocity and Range Echo Location System
U.S. Patent 5,872,628
February 16, 1999
An echo-location method for microwaves, sound, and light capable of using incoherent and arbitrary waveforms of wide bandwidth to measure velocity, range, and target size simultaneously at high resolution. Two interferometers having very long, nearly equal delays are used in series with the target interposed. The first interferometer imprints a partial coherence on an initially incoherent source. The second interferometer performs autocorrelation on the reflected signal to determine velocity. A coherent cross-correlation subsequent to the second interferometer with the source determines a velocity-discriminated range.
Steve P. Swierkowski
Micromachined Chemical Jet Dispenser
U.S. Patent 5,877,580
March 2, 1999
A dispenser for precisely ejecting chemical fluid samples. The dispenser is a microelectromechanical system (MEMS) device fabricated in a bonded silicon wafer and a substrate, such as glass or silicon, using integrated circuitlike fabrication technology amenable to mass production. Dispensing is actuated by ultrasonic transducers that produce a pressure wave in capillaries containing chemicals. The 10- to 200-micrometer-diameter capillaries can be arranged to focus in one spot or can be arranged in a larger dense linear array (about 200 capillaries). The dispenser, analogous to a computer ink-jet print head, does not heat up, so damage of certain samples does not occur. Applications are in biological sample handling and analytical chemical procedures.
Clifford B. Dane and Lloyd A. Hackel
All Solid-State SBS Phase Conjugate Mirror
U.S. Patent 5,880,873
March 9, 1999
A simulated Brillouin scattering (SBS) phase conjugate laser mirror uses a solid-state nonlinear gain medium instead of the conventional liquid or high-pressure gas medium. The concept has been effectively demonstrated using common optical-grade fused silica. An energy threshold of 2.5 megajoules and a slope efficiency of over 90 percent were achieved, resulting in an overall energy reflectivity of greater than 80 percent for 15-nanosecond, 1-micrometer laser pulses. The use of solid-state materials is enabled by a multipass resonant architecture that suppresses the transient fluctuations that would damage the SBS medium. This all-solid-state phase conjugator is safer, more reliable, and more easily manufactured than those based on prior designs. It allows nonlinear wavefront correction to be implemented in industrial and defense laser systems whose operating environments preclude the introduction of potentially hazardous liquids or high-pressure gases.
M. Allen Northrup, Conrad M. Yu, and Norman F. Raley
Porous Silicon Structures with High Surface Area/Specific Pore Size
U.S. Patent 5,882,496
March 16, 1999
Fabrication and use of porous silicon structures to increase surface area of heated reaction chambers, electrophoresis devices, thermopneumatic sensor-actuators, chemical preconcentrates, and filtering or control-flow devices. In particular, such high-surface-area or specific-pore-size porous silicon structures will be useful in significantly augmenting the adsorption, vaporization, desorption, condensation, and flow of liquids and gases in applications that use such processes on a miniature scale.
Anthony F. Bernhardt
Electrochemical Formation of Field Emitters
U.S. Patent 5,882,503
March 16, 1999
A method of electrochemical formation of field emitters that is particularly useful in the fabrication of flat-panel displays. Fabrication involves field-emitting points in a gated field-emitter structure. Metal field emitters are formed by electroplating, and the shape of the formed emitter is controlled by the potential imposed on the gate as well as on a separate counter electrode. The method allows sharp emitters to be formed more inexpensively and easily than they can be by the vacuum deposition processes used currently. The fabrication process involves etching of the gate metal and the dielectric layer down to the resistor layer and then electroplating the etched area and forming an electroplated emitter point in the etched area.
Robert Chow, Gary E. Loomis, and Ian M. Thomas
Optical Coatings of Variable Refractive Index and High-Laser-Resistance from Physical-Vapor-Deposited, Perfluorinated Amorphous Polymer
U.S. Patent 5,882,773
March 16, 1999
A method of making variable-index optical single-layer, optical multilayer, and laser-resistant coatings from a perfluorinated amorphous polymer material by physical vapor deposition. A vapor of polymer material, such as bulk Teflon AF2400, is deposited on a substrate to form thin layers that have an extremely low refractive index (about 1.10 to 1.31), are highly transparent from the ultraviolet through the near-infrared regime, and maintain the low refractive index of the bulk material. The refractive index can be changed by varying either the deposition rate or the substrate temperature. The coating can be used in antireflectors and graded antireflection coatings as well as in optical layers for laser-resistant coatings at optical wavelengths of less than about 2,000 nanometers.
Richard F. Post
Method for Leveling the Power Output of an Electromechanical Battery as a Function of Speed
U.S. Patent 5,883,499
March 16, 1999
A method of leveling the power output of an electromechanical battery during its discharge while maximizing its power output into a given load. The method employs the concept of series resonance, using a capacitor, the parameters of which are chosen optimally to achieve the desired near flatness of power output over any chosen charge-discharge speed ratio. Capacitors are inserted in series with each phase of the windings to introduce capacitative reactances that act to compensate the inductive reactance of those windings. This compensating effect both increases the power that can be drawn from the generator before inductive voltage drops in the windings become dominant and acts to flatten the power output over a chosen speed range. The values of the capacitors are chosen to optimally flatten the output of the generator over the chosen speed range.
Thomas E. McEwan
Ultra-Wideband Impedance Sensor
U.S. Patent 5,883,591
March 16, 1999
The ultrawideband impedance sensor (UWBZ sensor, or Z sensor) is implemented in differential and single-ended configurations. The differential UWBZ sensor employs a subnanosecond impulse to determine the balance of an impedance bridge. The bridge is configured as a differential sample-and-hold circuit that has a reference impedance side and an unknown impedance side. The unknown impedance side includes a short transmission line whose impedance is a function of the near proximity of objects. The single-ended UWBZ sensor eliminates the reference side of the bridge and is formed of a sample-and-hold circuit having a transmission line whose impedance is a function of the near proximity of objects. The sensing range of the transmission line is bounded by a two-way travel time of the impulse, thereby eliminating spurious Doppler modes from large distant objects that would occur in a microwave continuous-wave impedance bridge. Thus, the UWBZ sensor is a range-gated proximity sensor. It senses the near proximity of various materials such as metal, plastic, wood, petroleum products, and living tissue. It is much like a capacitance sensor, yet it is impervious to moisture. It has broad application in the replacement of magnetic sensors, particularly where nonferrous materials need to be sensed and in sensing full/empty levels in tanks, vats, and silos.