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Wide scanning spherical antenna
(United States Patent and Trademark Office, 1995-10-17)
A novel method for calculating the surface shapes for subreflectors in a suboptic assembly of a tri-reflector spherical antenna system is introduced, modeled from a generalization of Galindo-Israel's method of solving ...
Zero-current transition PWM converters
(United States Patent and Trademark Office, 1996-01-23)
A zero-current transition pulse-width modulated (ZCT-PWM) d.c.-d.c. converter allows minority-carrier semiconductor devices such as, for example, bipolar junction transistors (BJTs), insulated gate bipolar transistors ...
Soft switched three-phase boost rectifiers and voltage source inverters
(United States Patent and Trademark Office, 1997-05-27)
A boost rectifier is provided with an ultra high speed diode in its direct current rail to reduce diode reverse recovery loss with or without implementing a soft switching technique. Full zero-voltage-transition (ZVT) as ...
Ceramic materials with low thermal conductivity and low coefficients of thermal expansion
(United States Patent and Trademark Office, 1992-04-07)
Compositions having the general formula (Ca.sub.x Mg.sub.1-x)Zr.sub.4 (PO.sub.4).sub.6 where x is between 0.5 and 0.99 are produced by solid state and sol-gel processes. In a preferred embodiment, when x is between 0.5 and ...
Method of producing star-like polymers from lignin
(United States Patent and Trademark Office, 1991-11-19)
A method of producing prepolymeric materials from lignin is disclosed. The method uses lignin which has been hydroxyalkyl modified, such that the lignin is substantially non-phenolic and solvent soluble and/or liquid. The ...
Custom-fitting earplug formed in situ using foaming action
(United States Patent and Trademark Office, 1992-07-21)
A custom-fitting earplug (18) for hearing protection or other ear applications, or in-ear communications device mounting (40) is fabricated in situ by depositing a foaming material (14 or 24) within the person's ear (10 ...
Ophthalmic contact lens with internal fixation light for examination of the optic nerve
(United States Patent and Trademark Office, 1991-06-18)
An instrument and method for examining the optic nerve head (34) of a patient's eye (14) is disclosed. The instrument is comprised of a gonioscopic lens (10) a lens system (26) where the lens system (26) directs a collimated ...
Methods of preparing polymeric ketones
(United States Patent and Trademark Office, 1995-08-15)
A new method for preparing commercially valuable polymeric ketones is described. The method employs an .alpha.-amiononitrile as a monomeric unit whereby an amorphous, soluble polymer having protected carbonyl moiety is ...
Soft-switching PWM converters
(United States Patent and Trademark Office, 1995-08-15)
A full-bridge zero-voltage-switching pulse-width-modulated converter employs a saturable reactor in place of the linear inductor in order to reduce current stress on the active switches, reduce voltage stress on the rectifier ...
Water sample viral contamination detection system
(United States Patent and Trademark Office, 1996-06-18)
Viral contamination in water samples is detected using a medium which includes both a substrate for .beta.-galactosidase and E. coli with elevated levels of intracellular .beta.-galactosidase. The substrate is chosen to ...