Abstract: A rugged, flatly folding, portable chafing dish assembly is comprised of a cover, food pan, water pan, collapsible stand and heat source. The collapsible stand is rectangular and is comprised of four rigid plates forming the sides of the rectangular stand which are rotatably coupled together by means of a flatly folding piano hinge. The hinge is integrally formed with the sides and can be disassembled for cleaning. The two lateral sides of the stand are identical and interchangeable, as are the two end sides. The rectangular stand is provided with apertures through the lateral and end sides, both for air access to create a heat draft for the burner source when placed within the stand, as well as access to the burners when the chafing dish assembly is assembled. A rigid rectangular tray extends the length of the stand and connects to the end sides along an access aperture edge thereby rendering the otherwise collapsible rectangular stand rigid.

Abstract: Non-invasive near infrared optical medical imaging devices for both hematoma detection in the brain and early tumor detection in the breast is achieved using image reconstruction which allows a mapping of the position dependent contrast diffusive propagation constants, which are related to the optical absorption coefficient and scattering coefficient in the tissue, at near infrared wavelengths. Spatial resolutions in the range of 5 mm for adult brain sizes and breast sizes can be achieved. The image reconstruction utilizes WKB approximation on most probable diffusion paths which has as lowest order approximation the straight line-of-sight between the plurality of sources and the plurality of detectors. The WKB approximation yields a set of linear equations in which the contrast optical absorption coefficients are the unknowns and for which signals can be generated to produce a pixel map of the contrast optical resolution of the scanned tissue.

Abstract: Improved microsensors are provided by combining surface micromachined substrates, including integrated CMOS circuitry, together with bulk micromachined wafer bonded substrates which include at least part of a microelectromechanical sensing element. In the case of an accelerometer, the proof mass is included within the wafer bonded bulk machined substrate, which is bonded to the CMOS surface machine substrate, which has corresponding etch pits defined therein over which the wafer bonded substrate is disposed, and in the case of accelerometer, the proof mass or thin film membranes in the case of other types of detectors such as acoustical detectors or infrared detectors. A differential sensor electrode is suspended over the etch pits so that the parasitic capacitance of the substrate is removed from the capacitance sensor, or in the case of a infrared sensor, to provide a low thermal conductance cavity under the pyroelectric refractory thin film.

Abstract: The performance of a very large scale integrated READ ONLY MEMORY circuit is improved by a number of different improvements in various circuits and methodologies utilized in the memory. One of the improvements relates to control of an output buffer by a control circuit. The output enable signal to the output buffer is selectively inhibited by the control circuit which determines when the memory cycle is actually completed. Only after the memory cycle is actually completed is the conventional chip enable signal, CE, coupled to the enable input in the output buffer.

Abstract: A large amplitude sine wave is applied as the excitation potential to a amperometric measurement to produce a current output that is a phase shifted sine wave containing faradaic information at many frequencies. A current obtained from a conventional potentiostat coupled to the electrode is coupled to a lock-in amplifier that monitors the signal at one frequency at a specified phase angle. Since most of the background remains at the fundamental frequency, a higher harmonic of the fundamental frequency of the sinusoidal sweep frequency is monitored. By locking in on the higher harmonic components, the faradaic signal is therefore distinguished from the background signal. The background is diminished thereby allowing signal recognition at low analyte concentrations and increasing the signal-to-noise ratio.

Abstract: A monolithically integrated optical disk pickup head is comprised of three-dimensional collimating focusing lenses, a beam splitter and 45-degree reflectors that define an optical axis in free-space using surface micromachining technology to fabricate hinged vertical optical structures.

Abstract: A surface micromachined micromagnetic actuator is provided with a flap capable of achieving large deflections above 100 microns using magnetic force as the actuating force. The flap is coupled by one or more beams to a substrate and is cantilevered over the substrate. A Permalloy layer or a magnetic coil is disposed on the flap such that when the flap is placed in a magnetic field, it can be caused to selectively interact and rotate out of the plane of the magnetic actuator. The cantilevered flap is released from the underlying substrate by etching out an underlying sacrificial layer disposed between the flap and the substrate. The etched out and now cantilevered flap is magnetically actuated to maintain it out of contact with the substrate while the just etched device is dried in order to obtain high release yields.

Abstract: A continuously variable friction drive transmission for a bicycle is provided by driving the rear bicycle wheel by frictional engagement with a rotating rim driver. The rim driver has a lateral conical surface matching a lateral conical surface of a driver plate. A transmission driver wheel is selectively positioned between the lateral conical surfaces of the rim driver and driver plate. The position along a shifting arm of the transmission driver wheel determines the speed ratios obtained between the driver plate and rim driver. The driver plate is then rotated by the pedal assembly through a speed increasing coupling. The transmission driver wheel is always in contact with the driver plate.

Abstract: An improved pipe cleaning tool employing a cutting head and propulsor utilizes a plurality of roller cutters on the cutting head. The rolling cutters are coupled in a pairwise fashion to a rotatable car. The rotatable car in turn is pivoted to the cutting head. Each of the cars and, hence, the radial disposition of each of the roller cutters, is resiliently urged by a spring bias into a preferred radial disposition relative to the longitudinal axis of the cutting head. Moving the pipe cleaning tool through a curve or past other internal obstruction within the pipe is facilitated by rotation of the roller cutter cars and their corresponding roller cutters. In one embodiment, the propulsor disks in the propulsor unit are comprised of a plurality of rigid metal segments pivoted to the propulsor body.

Abstract: A one cycle control for controlling DC-to-AC switching converters is achieved by forcing the average of a controlled switched variable to be exactly equal to the control reference in each switching cycle. Potential subharmonic oscillations in a switching power amplifier which occurs in the DC-to-AC application of this method is prevented by adding an offset voltage to the averaged controlled switched variable which is fed back and compared to a control reference, which compares and is then used to switch the switching power amplifier. Switching errors are corrected by resetting the integrator which averages the controlled switched variable and a time interval at least an order or magnitude less than the switching time of the switches in the switching power amplifier.

Abstract: A structure for stabilizing the wavelength and output power of uncooled diode semiconductor lasers using stress caused by differential expansion to counteract the effects of temperature fluctuation is realized by restraining the thermal expansion of the active region. The thermal expansion is restrained first by encapsulating the active region of the laser within a low expansion cap, and second, by applying stress to the active region by means of a high thermal expansion stress element mechanically coupled to the active region and restrained within the low expansion cap. As the temperature of the laser increases and it would normally attempt to expand, the stress element expands to even a greater degree with the combination of the active region and stress element both being contained within the low thermal expansion cap. The result is that physical thermal expansion of the active region is substantially eliminated or reduced and it operates under higher internal pressure.

Abstract: A process for production of self-assembled quantum dots is described which does not entail any processing steps before or after growth of the quantum dots. The process uses in situ formation of three dimensional islands which occurs during epitaxy of material with a different lattice parameter than the substrate. Further deposition of the substrate material then produces single or multiple buried two dimensional layers of randomly distributed or selectively positioned and substantially uniform sized quantum dots. These layers are free of defects and interface states. The lateral dot diameters vary between 140 to 300 Angstroms by appropriate choice of deposition parameters.

Abstract: The invention is a control circuit for controlling an interrupt driver coupled to the data outputs of a memory having address transition detection circuitry. The memory is operable in a standby and an active memory mode in sequential memory cycles. The control circuit comprises an output enable latch circuit which provides internal memory signal of whether the memory was operating in the standby or active mode during a previous memory cycle and a data latch circuit which provides an internal memory signal of whether a new read cycle is beginning within the memory. The data latch circuit is reset when address detection has occurred within the memory. A logic circuit combines an output of the data latch circuit, which is indicative of a memory read cycle, with an output of the output enable latch circuit, which is indicative of whether the prior memory cycle was standby or active.

Abstract: A wound therapeutic mixture is formulated to work alone or in combination with human growth factors, and is useful for treatment of burns, open sores, incisions, and wounds. The mixture is comprised of a medical grade hyaluronic acid (hyaluronan) and tissue culture grade plasma-fibronectin in combination with calcium, phosphate, uric acid, urea, sodium, potassium, chloride, and magnesium, all elements found in amniotic fluid. The mixture creates a moist healing environment which simulates the fetal in utero wound healing matrix. The therapeutic mixture can be sterile or contain an FDA acceptable preservative system. The compositions may be in the form of a liquid, creme, ointment, gel, hydrogel, hydrocolloid or dressing.

Abstract: Operation of an address latch circuit in a memory is conditioned on first receiving a ground surge control logic signal, SURG, which is generated only when data output drivers switch. This prevents noise from these same drivers from falsely addressing the memory. Metastability is prevented by selecting the trigger points of the gates which make up the latch such that an output is not generated until input or intermediate circuitry has stabilized and by providing a favored output condition in the input or intermediate circuitry when conflict between almost simultaneous inputs occur. Feedback of the output of the latch to its input further reduces metastability.

Abstract: A circuit which differentially amplifies voltages that are close to ground with differences of about 0.15 volts uses voltage level shifters, a cross coupled current source and inverters to provide increased speed, accuracy, and gain. Symmetric cross coupled current sources are used in a differential amplifier to provide the differential amplifier with a balanced load. A symmetric and balanced layout senses smaller voltage differences and operates faster than would otherwise be possible. The gain of the cross coupled current source is controlled by four FETs. Voltage level shifters at the input to the differential amplifier allow the differential amplifier to sense signals that are close to ground with a voltage difference of about 0.15 volts. The voltage level shifters also shift the signals to a voltage that increases the gain of the differential amplifier. Two inverters block half level signals from being outputted until the sense amplifier data has been latched.

Abstract: A method of programming or writing to an RFID tag with a transient pulse at both high and low frequencies, i.e. in the GHz and KHz ranges is described. Programming an RFID tag using transient pulses rather than a long duration regulated signal allows for less control circuitry, less programming time, less energy, less cost and power requirements for the RFID tag.

Abstract: Orthogonal sensors, which are comprised of two or more electrodes and generally disposed circumferentially on the catheter at given longitudinal point along the catheter, receive signals which are differenced within a differential amplifier to produce a signal indicative only of the localized biopotential heart activity at a predetermined point in the myocardium. The orthogonal sensors are disposed in an ablative tip of the catheter to allow sensing of the localized cardiac activity which is adjacent to or in contact with the ablative tip during extirpation procedure or during the delivery of radio frequency energy during ablation. Sensing of the localized cardiac activity occurs simultaneously either with the ablation so that detailed and accurate electrocardiograms of the very tissue being ablated can be recorded.

Abstract: Nanometer holes can be reliably and repeatedly defined in the tips of cantilevered probes and used in various types of scanning microscopy by voltaicly defining the hole within a conductive layer disposed on the tip. The field strengths of the apex of the tip are sufficient to cause evaporation of the metal or conductive material from the apex onto an opposing sample substrate. The hole opens on the apex of the tip and is self-limited by the inherent threshold voltage strength required for vaporization, which voltage strength falls off rapidly from the tip. The hole may be defined in conductive layers in various combinations with oxide layers, other metal layers and semiconductor materials to define Schottky diodes, thermocouple junctions, near-field optical detectors, and atomic force tips. As a result, two or more physical interactions may be simultaneously exploited between the fabricated tip and the scanned sample from which a scanned image may be produced.