Abstract: A method, apparatus, and article of manufacture which provides for visually depicting join relationships in a database management system. The method comprises the steps of visually depicting join relationships on a monitor coupled to a computer and receiving a join command from a user input device into the computer, wherein the join command selectively chooses a join relationship. The join relationships are visually depicted in a window displaying matching records in a first table joined to matching records in a second table, all records in a first table joined to matching records in a second table, and matching records in a first table joined to all records in a second table.

Abstract: A method, apparatus, and article of manufacture which provides for finding database management information on a computer in a simple, user-friendly way to minimize errors and maximize database usership. The invention displays a window containing a card metaphor in a graphical user interface on a computer display. The window allows the user to enter a find type and a find condition selected from a displayed menu. The window also displays a natural language description of the current status of the find request, allowing the user to see, in real time, the scope of the request and the databases affected.

Abstract: A photoluminescence sensor for detecting a photoluminescent light from a toluminescent material is disclosed. In a preferred embodiment the photoluminescence sensor comprises: a source of light; a concave mirror having at least one perforation for passing the source light through the at least one perforation; an optical waveguide having proximal and distal ends with the photoluminescent material being disposed at the distal end; an objective for directing the source light into the proximal end of the waveguide; an objective for receiving photoluminescent light and for focusing the photoluminescent light onto the perforated concave mirror; a liquid filter for passing the photoluminescent light reflected from the perforated concave mirror to a detector to detect the photoluminescent light.

Abstract: The present invention is a technique for a defrosting operation of a heat pump. External air provides the heat for defrosting the exterior heat exchanger by operating the exterior fan during times when the compressor is not operating, the temperature of the exterior heat exchanger is below freezing and the exterior air temperature is above freezing. In accordance with one embodiment of the present invention the temperature of the exterior heat exchanger and the exterior are measured via separate temperature sensors. In accordance with an alternative embodiment, the exterior heat exchanger temperature is measured via a single temperature sensor and the exterior fan is operated for a predetermined interval of time after the compressor is stopped. Thereafter the exterior fan is operated only so long as the temperature remains at freezing. In a still further embodiment, the exterior fan is operated only so long as it remains less than or equal to freezing and does not reach a plateau at less than freezing.

Abstract: The present invention is a technique for a defrosting operation of a heat pump. External air provides the heat for defrosting the exterior heat exchanger by operating the exterior fan during times when the compressor is not operating, the temperature of the exterior heat exchanger is below freezing and the exterior air temperature is above freezing. In accordance with one embodiment of the present invention the temperature of the exterior heat exchanger and the exterior are measured via separate temperature sensors. In accordance with an alternative embodiment, the exterior heat exchanger temperature is measured via a single temperature sensor and the exterior fan is operated for a predetermined interval of time after the compressor is stopped. Thereafter the exterior fan is operated only so long as the temperature remains at freezing. In a still further embodiment, the exterior fan is operated only so long as it remains less than or equal to freezing and does not reach a plateau at less than freezing.

Abstract: The present invention is a technique for a defrosting opereation of a heat pump. External air provides the heat for defrosting the exterior heat exchanger by operating the exterior fan during times when the compressor is not operating, the temperature of the exterior heat exchanger is below freezing and the exterior air temperature is above freezing. In accordance with one embodiment of the present invention the temperature of the exterior heat exchanger and the exterior are measured via separate temperature sensors. In accordance with an alternative embodiment, the exterior heat exchanger temperature is measured via a single temperature sensor and the exterior fan is operated for a predetermined interval of time after the compressor is stopped. Thereafter the exterior fan is operated only so long as the temperature remains at freezing. In a still further embodiment, the exterior fan is operated only so long as it remains less than or equal to freezing and does not reach a plateau at less than freezing.

Abstract: The present invention is an adaptive method and apparatus for detecting the formation of frost in a heat pump. The compressor cycle is interrupted and a defrosting operation is begun if the difference between the exterior ambient temperature and exterior heat exchanger temperature exceeds a difference function of the exterior ambient temperature. The length this defrosting cycle is measured and the difference function is altered if the measured length deviates from a predetermined length of time. The frost formation difference function is initially set as a linear approximation. Thereafter the difference function value at the particular exterior ambient temperature is increased if the length the defrosting is greater than an upper limit value of six minutes and decreased if the length the defrosting is less than a lower limit value of four minutes.

Abstract: The present invention is a method and apparatus for determining the exterior ambient temperature in a heat pump. In accordance with the prior art the heat pump defrosts the exterior heat exchanger if the exterior heat exchanger temperature has a predetermined relationship to the exterior ambient temperature. The exterior heat exchanger temperature is measured directly via a temperature sensor. The improvement of the present invention includes operating the exterior fan after operation of the compressor, while repetitively measuring the temperature of the exterior heat exchanger until reaching a plateau temperature other than freezing. The exterior ambient temperature is set to the plateau temperature. In the event that the plateau temperature equals freezing, the exterior ambient temperature is set equal to a compromise temperature slightly above freezing, preferably 34 degrees Fahrenheit.

Abstract: A two-gate field-effect transistor (FET) is designed to operate at cryogenic temperatures (circa 1.degree.-20.degree. K.). For an N channel FET, the low-concentration weak-P type material used for the channel region is built into an intrinsic (or near-intrinsic) layer which in turn is built on a P type substrate. The first gate corresponds to a conventional FET control gate. The second gate may be designated a weak-source gate and is directly above a corresponding weak-source region which is itself adjacent to the conventional (strong) source region. The weak-source gate is placed at a fixed positive potential with respect to the source region so that the electrons will collect in the conduction band within the weak-source region. Once the required fixed weak-source gate potential has been established, the control gate functions in a conventional manner even when the device is at a cryogenic temperature.

Abstract: A preferred embodiment of the invention is a three-gate charge-coupled device (CCD) which is designed to operate at cryogenic temperatures (circa 1-20.degree. K). For an N channel device, a low-concentration N type material is separated from a P type substrate by a thin layer of intrinsic material. The active detection area is underneath a transparent detector gate which functions as the device's input gate. Electrons excited into the conduction band under the detector gate flow into the conduction band under the adjoining second gate which functions as an integrating gate by collecting the electrons that flow from under the input gate. The third gate also adjoins the second gate and is called the readout gate. When the readout gate is at a low potential, it dams up the electrons in the conduction band under the integrate gate.

Abstract: A relatively thin layer of extrinsic material formed on the top surface of a nearly intrinsic semiconductor substrate forms the detector area of an infrared detector device. A source region is provided along a portion of the perimeter of the detector area and is electrically coupled to the extrinsic detector area by means of an external connection. A drain channel is provided which is separated from the detector area by a gate region. The concentration of the extrinsic material in the detector area is sufficient for it to be at least a poor conductor. Thus, replacement electrons can flow from the source region into the extrinsic detector area via the external connection and electrical charge-neutrality can thereby be maintained at the extrinsic sites. The gate electrode forms a fringing field extending into the detector area which facilitates conduction from the detector area to the drain channel during the read-out process.