Abstract: A switched capacitor circuit is described that uses two switchable operational amplifiers that operate in parallel and in alternate clock phases. In a preferred embodiment of the invention, the two operational amplifiers may be implemented by a single two-stage operational amplifier having a common input stage and two switchable output pairs. The novel switched capacitor circuit may be used in any application that uses a conventional switched capacitor circuit, such as an integrator and a filter means.

Abstract: Fluorescence imaging of tissue is used as a diagnostic tool in which geometric effects and specular reflections are compensated for by normalizing a fluorescence image with a cross-polarized image.

Abstract: The present invention provides methods for obtaining highly stereoregular polyacetylenes from organorhodium catalysts in aqueous media in high yield. These methods afford substantial advantages in that they are rapid, economical, and utilize environmentally benign solvents. The present invention further provides methods for making thin films of polyphenylacetylenes that are tough and transparent.

Abstract: A three stage amplifier is disclosed provided with a novel frequency compensation technique. Only a single feedback loop with a single compensation capacitance is provided. Instead of a conventional nested compensation technique, damping factor control is provided by means of a fourth gain stage in order to stabilize the amplifier. The resulting amplifier is particularly useful to drive large capacitive loads for low-voltage low-power applications.

Abstract: A circuit architecture for computing the outputs of odd and even symmetric spatial filters simultaneously comprises at least two resistive networks interconnected by at least one controlled current source. In one embodiment the nodes of the resistive network are arranged in a two-dimensional array to allow filtering of two-dimensional signals such as images. The resulting filters are orientation selective. The spatial orientation and the scale of the filter can be selected by appropriately tuning the resistive elements forming the resistive networks and the gains of the controlled sources. The controlled sources may be voltage controlled (eg transconductance amplifiers) or current controlled. This circuit architecture may be implemented in VLSI to incorporate both image sensing and orientation selective filtering on the same chip.

Abstract: A servowriter positioning apparatus for hard disk drives comprises an optical read head 2 for directing three focussed light beams on grating sections formed at the end of a grating member 1 connected to the servo write head(s) 3 in order to indicate the position and movement of the head(s) 3. The optical read head 2 may be based on CD or DVD technology. The servo write head(s) 3 are mounted on an actuator arm 5 to which the grating member 1 is fixed for rotation therewith and which are both driven in rotation by a rotary actuator. The grating member 1 comprises two grating sections 11,12 separated by a smooth section 13 for generating a focus error correction signal. The apparatus of the invention can be used to sense and control the position and movement of the servo write heads, or of the read/write heads of the hard disk themselves, thus eliminating the need for any servo pattern.

Abstract: A low-diversity antenna diversity receiver suitable for TDMA PCS handset implementation employing two diversity branches. The receiver is capable of selecting a diversity scheme which is anticipated to give optimum signal reception among a plurality of diversity schemes installed on the receiver. This receiver, more conveniently termed multi-diversity receiver comprises a single conventional wireless digital receiver chain augmented with a few additional low-cost passive RF components and minor control circuits. A plurality of diversity algorithms, for example, selection diversity (SD), equal-gain combining (EGC) or interference-reduction combining (IRC) scheme, which are suitable for implementing on this multi-diversity receiver are also described. Simulation results showing performance of this multi-diversity receiver are also presented.

Abstract: A method and apparatus are disclosed for the dimming control of a fluorescent lamp driven by an electronic ballast. A small portion (eg less than 15°) of the phase of the input supply voltage is removed, and the precise amount of the phase removed is used to generate a switching signal that controls the switching frequency of the electronic ballast and hence the light power output. The switching frequency is generated by producing pulses of a width proportional to the amount of phase removed, integrating the pulses to produce a voltage proportional to the phase removed, converting that voltage to a current that varies with a frequency depending on the voltage, and using that varying current to generate the switching frequency.

Abstract: An admixture for enhancing the durability of concrete to repeated freeze-thaw cycles is disclosed. The admixture comprises as an essential element a natural polymer material derived from millet. The admixture further comprises smaller quantities of naphthenic sulfate salt, triethanolamine and formaldehyde. In addition the admixture can improve concrete's impermeability and chloride ion binding capability.

Abstract: An information network architecture is described that can handle both ATM and IP traffic. The network emplpoys unbuffered switches that employ a system of priorities in the handling of ATM and IP traffic whereby ATM data is given higher priority to IP traffic, and the remaining cells of an IP packet that is being transmitted are given greater priority than the first cells of a new IP packet so that the cells of different IP packets are not interleaved.

Abstract: 3-Hydroxy-propanamine derivatives and acid salts thereof having chiral centers at the C.sub.1 and C.sub.2 positions exhibit synaptosomal reuptake inhibition of neurotransmitters, and as such represent a new class of psychotropic agents useful as antidepressants.

Abstract: A graphite intercalation compound is disclosed in which formic acid (HCOOH) is the intercalate. The GIC may be formed by an electrochemical process using formic acid solution as both the electrolyte and as the intercalate source. The resulting formic acid GIC may be expanded by rapid heating to produce an expanded graphite product that in turn may be mechanically processed into flexible graphite.