Abstract:
Methods of fabricating electrical contacts on both sides of a thin membrane to form a millimeter wave, self-aligned, opposed gate-source transistor are disclosed. The transistor structure has a subhalf-micron gate, dual-drains placed symmetrically around both sides of the gate, and a source approximately half the length of the gate. The source is directly opposite, and centered under, the gate on the opposite surface of a semiconductor thin film. The gate electrode is fabricated on the first surface of the thin film using conventional single surface lithography, and is used as a conformed mask for the source lithography, thereby self-aligning the source to the gate. The source is formed by resonant dielectric lithography, wherein the gate side of the thin film is irradiated by collimated ultraviolet light to expose a negative resist on the source side with a resolution of less than a wavelength. Lateral diffraction effects affect the relative dimension of the source with respect to the gate. The electron-beam lithographic process utilizes electron scattering in the thin film for the same purpose. This new untraviolet lithography process avoids the need to handle the thin film until after source metallization has been completed.
Abstract:
One embodiment of the invention includes a CVG system. A plurality of electrodes electrostatically force a resonator into a periodic motion based on a drive axis forcer signal applied to a first set of the plurality of electrodes and a sense axis force-rebalance signal applied to a second set of the plurality of electrodes, and provides a sense axis pickoff signal and a drive axis pickoff signal. A gyroscope controller generates the drive axis forcer signal based on the drive axis pickoff signal and calculates an angular rate of rotation about an input axis based on the sense axis force-rebalance signal. The gyroscope controller modulates a predetermined disturbance signal component onto the sense axis force-rebalance signal and to control a modulation phase of the sense axis force-rebalance signal based on detection of the predetermined disturbance signal component in the sense axis force-rebalance signal to substantially mitigate bias and scale-factor error.
Abstract:
An elevator assembly having a looped track assembly and a chain assembly having rollers which roll on the looped track assembly. The chain assembly includes spaced apart pin holders extending from the chain. A sprocket drive assembly engages the chain assembly.
Abstract:
First and second inertial instruments have parallel sense axes and produce respective first and second output signals using associated first and second scale factors. Bias errors are estimated using the change in state of sign of the first and second scale factors. A substitute scale factor is determined to be an equivalent of the second scale factor and is based on the first scale factor and a difference between the first and second scale factors. Errors in the second scale factor are calculated based on the first scale factor and the substitute scale factor where a sign of one of first and second scale factors changes going from the first time interval to the succeeding time intervals. First and second corrected output signals are generated based on the respective first and second output signals and correction of the second scale factor error.
Abstract:
There is disclosed a novel woven multiplex forming fabric defining pockets in one surface thereof into which cellulosic fibers in an aqueous medium are flowed under conditions of flow and rate of water removal that establish high shear fluid flow and result in the orientation of fibers and/or fiber segments at an angle with respect to the plane of the forming fabric and their capture in the pockets and in the areas of the fabric adjacent the pockets.
Abstract:
A method and apparatus are described for the manufacture of surgical sponges defined by a sponge body with at least a segment of a string, preferably containing a material opaque to x-rays, joined to the sponge body. The apparatus provides for the manufacture of the surgical sponges in an automatic manner and continuous manner by feeding a length of the string from a string supply and an end portion of sponge from a supply of sponge in directions substantially ninety-degrees to one another to an area of intersection area where a segment of the string overlies the sponge at a selected distance from the end thereof remote to the supply of sponge. The string segment is joined to the sponge, preferably by an ultrasonic welding mechanism. The sponge end containing the joined string is then severed at a preselected location depending upon the width of sponge body desired. The cutting mechanism used to sever the sponge and the welding mechanism are moveable as a single unit to alternately place the welding mechanism over the segment of the string and cutting mechanism at the preselected location on the sponge. The sponge bodies serially connected by the string at spaced apart locations are separated into discrete surgical sponges by sequentially displacing the string-connected sponge bodies to a string and sponge cutting arrangement where the string is first cut at an edge of each sponge and then an excess of the sponge adjacent this edge of each sponge is severed.
Abstract:
A field-effect transistor (FET) and a corresponding method for its fabrication, the transistor having a source and a gate located at opposite faces of an active channel region formed in a substrate, the source being substantially shorter in effective length than the gate and located symmetrically with respect to the gate. The transistor also has two drains, located one at each end of the channel region, and charge carriers flow from the source to the drains in two paths, under control of the same gate. Electrical contact with the source is made from beneath the substrate, while contact with the gate and drains is made from above. The resulting device has a large incremental transconductance and relatively small parasitic impedances, and therefore can operate at much higher frequencies than conventional FET's.
Abstract:
An IMPATT diode mounted in a double-tuned resonant cavity to exhibit stability by suppressing subharmonic frequencies is disclosed. A foreshortened quarter wavelength section is connected to the diode to form an equivalent parallel resonant circuit at one end thereof. At the other end of the quarter wavelength section is an odd-quarter wavelength tuning slug which provides a section which exhibits a second, series equivalent resonant circuit. To provide increased stability at subharmonic frequencies, a half-wavelength tuning slug is disposed adjacent to the odd-quarter wavelength section. The half wave tuning slug is virtually transparent at the operating frequency, but is a quarter-wavelength at the first subharmonic, and thus exhibits a high resistance at the subharmonic frequency.
Abstract:
A method and apparatus for use in the manufacture of improved molded pulp products are disclosed wherein foraminous molds disposed over openings in a liquid impervious belt are moved beneath the surface of a flowing furnish and suction is applied to draw liquid through the molds and deposit a layer of pulp on each mold. Thereafter, the pulp deposit on each mold is simultaneously subjected to a generally uniform pressing with a second belt and suction which forms a smooth exposed surface on the pulp deposit and removes a portion of the liquid therein.
Abstract:
A method and apparatus are disclosed for making a molded pulp product such as a plate or the like which has an upper liquid impervious layer integrally secured thereon. The pulp product is formed on a foraminous mold and, together with the mold, is heated to the softening temperature of a liquid impervious thermoplastic sheet material which is caused to be cut to size by engagement with a cutting edge on the mold whereafter the severed portion is drawn by suction and bonded to a selected surface area of the pulp product.