Abstract:
Annealed copper foil (12) is coated with chromium film (16), followed by coating with an appropriate thickness of gold film (14) and is thermocompression bonded to an aluminum metallized substrate (18) on a silicon chip (30) to provide solderable, high current contacts to the chip. The foil is formed into appropriate electrical network-contact patterns (40) and is bonded to the silicon chip only where aluminum metallization exists on the chip. Leaf (wing) portions (46) of the foil extend beyond the boundaries of the silicon chip for subsequent retroflexing over the foil to provide electrical contact at predesignated locations (49). External contacts to the foil are made by penetrating through a ceramic lid positioned directly above the foil area. Thus, direct thermocompression bonding of a principally copper foil to aluminum semiconductor pads can replace current gold detent/pump connections by securing a copper conductor to a silicon chip through an intermetallic AuAl2 link and an aluminum stratum.
Abstract:
Sigma-delta analog-to-digital conversion is used in sensing apparatus that generates a digital signal descriptive of light energy received by a photosensor, such as one of a plurality of photosensors that together receive various elements of a radiant-energy image. A preamplifier generates an analog output signal responsive to the photocurrent of the photosensor, which analog output signal is undesirably accompanied by wideband noise. The analog output signal is supplied to a sigma-delta analog-to-digital converter, the decimation filter of which not only suppresses in the digital signal a component arising from the quantization noise from the sigma-delta modulator portion of the analog-to-digital converter, but also suppresses a component arising from remnant wideband noise from the preamplifier.
Abstract:
A drive (10) for positioning a control rod (12) in nuclear reactor core (104) is disclosed. The drive includes a turbine rotor (34) joined to hollow spindle (26) in a housing. The spindle has a piston (82) disposed therein and a piston rod (82b) extending therefrom and through a bottom end of the spindle for being joined to the rod. A pressurized fluid is provided into the spindle (26) for exerting a pressure force against the piston (82) for moving the piston for selectively gripping the control rod (12). Interruption of the pressurized fluid to the spindle causes ungripping of the control rod.
Abstract:
In accordance with the present invention, a nuclear reactor (100) with a recirculating heat transfer fluid has a bi-level core which provides enhanced flexibility in fuel arrangement. The bi-level core (104) includes two sets of fuel units, one set arranged on a first level (130), the other set arranged on a second level (128). Preferably, fuel units of the second level are arranged in vertical alignment with fuel units of the first level. This permits a fuel unit of the first level (130) to be accessed by removing only the adjacent fuel unit of the second level (128). During refueling operation, fuel units can be shifted from on level to the other, providing additional flexibility in arranging units at various stages of burnup. Preferably, fuel units of the first level (130) are inverted relative to the fuel units of the second level (128). The inversion provides for placing plenum sections of fuel rods in different levels away from each other so that the plenums do not introduce a discontinuity in neutron generation, and allows for more uniform axial fuel burnup. The bi-level core allows fuel to be initially positioned in the second level for conversion of fertile fuel to fissile fuel, and then repositioned to the first level for more complete axial burnup. In a preferred embodiment the first level boils water to generate saturated steam, and the second level is cooled by the saturated steam and generates superheated steam.
Abstract:
Fresh fuel bundles are inserted into core locations with small coolant flow orifices, while mid-life fuel bundles are inserted into core locations with large coolant flow locations. Thus, fissile fuel production is promoted at the expense of fissioning early in a bundle lifetime, increasing the effective quantity of fuel available for energy production. Moreover, fissioning is promoted at the expense of conversion later in the bundle lifetime to enhance reactivity of the remaining fissile material and to minimize the further production of fissile fuel. The net result is longer fuel lifetimes and reduced radioactive waste.
Abstract:
Deghosting apparatus for eliminating multipath signal components in a received transmitted television signal incorporates a training signal which is a finite duration sequence of repetitions of a 2n-1 pseudorandom sequence. The 2n-1 pseudorandom sequences (12) are mapped into 2r sample intervals at either the transmitter (13) or the receiver (28) to facilitate fast Fourier transform processing. Power spectra of the received and mapped training signal (30) and a stored version (44) of the training signal are deconvolved (36) with the deconvolution coefficients produced in logarithmic form. The logarithms (32, 34) are inverse Fourier transformed (38) to produce (40) delay coefficients related to the time of occurrence of the multipath signals, which coefficients are utilized to program variable delay circuitry in an adaptive filter (42) to cancel the multipath components.
Abstract:
The capacitances of a pair of capacitors associated with a neural net are arranged to be complementary in value, even where their differential capacitance is subjected to variation, so the sum of the capacitances remains equal to a constant, Ck. Each of a set of component capacitors with capacitances related in accordance with powers of two is selected to be a component of one or the other of the pair of capacitors, the selecting being done by field effect transistors (FETs) operated as transmission gates. The gate signals for the FETs are respective ones of the bits in a binary number stored in a word storage element of a semiconductor memory.
Abstract:
A system for synchronizing first and second (A) video signals which are to be combined is disclosed. The second signal is a time compressed digital signal containing macro blocks (B) of composite data preceded by a field sync flag (SF) synchronized with the field rate of the first signal. Each macro block contains a video block including a plurality of image line blocks (C). Each line block contains multiplexed video data such as luminance and chrominance information preceded by a marker flag (FF;LBF). The flag preceding the first line block in a video block is a field flag (FF) which identifies the beginning of a scanning field associated with that video block. The flags (LBF) preceding other line blocks in that video block identify the other line blocks respectively. Each flag contains a unique data preamble which identifies the associated line block. Illustratively, field flag data includes unique header, field number, and 'performance index' data (PI) for controlling data quantization. Line block flag data includes unique header, line block number and performance index data (PI).
Abstract:
A circuit breaker warning and control relay provides visual indication of an impending overcurrent condition. Sufficient time is thereby allotted for manual intervention to prevent damage to material and equipment utilized within sensitive manufacturing processes. The relay can be arranged to automatically shut-down selected equipment in a predetermined order for load-shedding implementation.
Abstract:
Polymer blend compositions comprise a polycarbonate, a styrene-acrylonitrile-maleic anhydride terpolymer and from about 5 to about 40 weight percent glass fibers. Preferably, the compositions comprise from about 5 to about 65 weight percent of the polycarbonate and from about 10 to about 80 weight percent of the terpolymer. The compositions may optionally include a small amount of an ABS resin in order to improve the compatibility of the polycarbonate and the terpolymer. These compositions exhibit advantageous improved combinations of such properties as heat resistance, strenght, and modulus which allows the blend to be used in engineering thermoplastic applications.