Abstract: Patterned surfaces for the selective adhesion and outgrowth of cells are useful in cell culture devices, prosthetic implants, and cell-based microsensors. Such surfaces may be prepared by a deep ultraviolet photolithographic technique.

Abstract: Tubules which contain an active agent in their lumen and compositions containing such microtubules are effective for providing a slow, controlled release of the active agent. Such microtubules are useful in the production of coating compositions for the protection of surfaces coming into contact with water, adhesive resins for the production of laminated wood products, and devices for dispensing pesticides.

Abstract: A method and apparatus for resolving a radar return by an object or layer below the earth's surface from a radar return of an air-to-earth interface. More specifically, a method and apparatus for generating short pulsewidth, broad bandwidth RF signals and for effecting control and timing of transmitted and received radar signals in order to focus an antenna illumination pattern. The apparatus includes an antenna array including a plurality of antenna elements which transmit and receive the RF pulsed signals and a custom control module which generates the control signals fed to the antenna array to delay the RF pulse signals with respect to each other, upon transmission and receipt, in order to form transmit and receive antenna illumination patterns.

Abstract: A feedback operated DC bridge circuit for monitoring the voltage variations in a voltage divider circuit using a voltage controlled resistance component to reach a null balance across the bridge. Amplification is provided at higher accuracy near the null point when the voltage difference across the bridge is zero. The feedback bridge circuit includes an integrator which directly drives the controlling component to the value of the resistance in an unknown branch to force the null condition. The voltage controlled component (configured as a discrete metal oxide semiconductor device or bipolar junction transistor) and the balancing scheme are suitable for microfabrication and provides noise-rejection enhancement. The interconnected integral feedback of the autonulling DC bridge enables both a neural network for pre-processing sensor input in a spatial domain as well as general analog computation that mimics a first order differential equation in the form of the system state equation.

Abstract: Irradiating, with ultraviolet light, surfaces which contain thiol groups, epoxy groups, or vicinal diol groups, results in surfaces which exhibit a reduced adsorption of biomolecules. In the case of surfaces having thiol groups such irradiation also results in a reduced capacity for the bonding of heterobifunctional crosslinking reagents. Such irradiation may be carried out in a patternwise fashion to obtain patterned surfaces.

Abstract: Catalytic colloidal metal particles bound to a biomolecule such as an antibody, avidin, or streptavidin are useful for detecting the presence of the biomolecule in an assay such as an immunoassay.

Abstract: High aspect ratio metal microstructures may be prepared by a method involving(i) forming a layer of a photoresist on a substrate;(ii) exposing the layer to actinic radiation in an imagewise manner and developing the exposed layer to obtain a surface which contains regions having no remaining photoresist and regions covered with photoresist;(iii) metallizing the surface to form a layer of metal on the region of the surface having no remaining photoresist and on the sides of the regions of photoresist remaining on the surface; and(iv) optionally, stripping the photoresist remaining on the surface.Such microstructures are useful as electron emitters, anisotropic high dielectric interconnects, masks for x-ray photolithography, carriers for the controlled release of active agents, and ultramicroelectrode arrays.

Abstract: Patterned surfaces for the selective adhesion and outgrowth of cells are useful in cell culture devices, prosthetic implants, and cell-based microsensors. Such surfaces may be prepared by a deep ultraviolet photolithographic technique.

Abstract: A device for detecting the presence or concentration of an analyte, a method of making the device, and a method of detecting the presence or concentration of an analyte. The invention features one or more supports, such as beads, which carry a thin film of polymer substrate. The polymer substrate has a sensing reagent and a porous matrix. The sensing reagent alters the optical properties of the polymer substrate in the presence of analyte.

Abstract: An optically bidirectional electrically controlled optical switch having reduced light loss includes an electro-optic crystal having one set of fast and slow optical axes and having at least two light paths for receiving light beams through the crystal, the crystal exhibiting electric field induced birefringence such that a light beam passing through the crystal along a light path and having a plane of polarization oriented in a first direction may have its plane of polarization switched from the first direction to a plane of polarization oriented in a second direction. Beam splitting polarizers are disposed at each end of the electro-optic crystal and optically aligned with the two light paths. The beam splitting polarizers split the optical beam into two light beams having planes of polarization oriented in the first and second directions when transmitting light to the two light paths and combine the two light beams into a single light beam when receiving light beams from the two light paths.

Abstract: A stress sensor having directional measurement capabilities based on the photoelastic effect in isotropic photoelastic materials. Directional measurement capability is achieved in the sensor by the incorporation of three different optical axes passing through the photoelastic element. This creates three independent stress sensors which utilize a single sensing element. Each of the three independent stress sensors are sensitive to applied stress in different directions. The response of each of the sensors is analyzed and the magnitude and direction of incoming stress is determined. The use of a sum-difference output detection scheme results in immunity to light source intensity variations, optical fiber microbending losses, and fiberoptic connector losses. The stress sensor is immune to electromagnetic interference (EMI) and electromagnetic pulse (EMP), and is compatible with fiberoptic data transmission and control lines.

Abstract: Devices in which a Langmuir-Blodgett film of a liquid crystal polymer is disposed between electrodes on the surface of a substrate exhibit fast ferroelectric switching in response to an electric field generated by the electrodes, and Langmuir-Blodgett films of a liquid crystal polymer exhibit pyroelectric properties even at thicknesses below 10-15 .mu.m.

Abstract: A self-contained autonulling bridge circuit based on phase-sensitive deteon of an impedance to be measured is described. The system utilizes a feedback structure to control a variable impedance in order to establish the null of the bridge. The system utilizes a voltage-variable impedance having both resistance and capacitance and provides the phase sensitive relationship in the control means in order to provide highly accurate measurement of an unknown test impedance. The ability to measure small changes in impedance provides particularly useful application to the area of biological sensor impedance measurement or electrochemical impedance measurement using silicon-based devices.

Abstract: Liquid crystal polymers containing 0.1 to 0.9 mole % of repeating units bing a mesogenic side group and 0.1 to 0.9 mole % of repeating units which do not bear a mesogenic side group in which the mesogenic side group has the formula:--(CH.sub.2).sub.n O--R.sub.1 --X--R.sub.2R.sub.1 is 1,4-phenylene or 4,4'-biphenylene;X is --COO-- or --OCO--;R.sub.2 is ##STR1## wherein k is 0 or 1, * indicates an optically active center;Z is NO.sub.2, F, or Cl;R.sub.3 is C.sub.l H.sub.2l+1, --*CH(CH.sub.3)C.sub.p H.sub.2p+1 --CH.sub.2 C.sub.q F.sub.2q+1, --*CH(CH.sub.3)COOC.sub.t H.sub.2t+1 (wherein l and p are each independently an integer of from 1 to 10 and q and t are each independently an integer of from 1 to 6); and n is an integer of 4 to 12;exhibit fast response times.

Abstract: A sensor utilizing a single electro-optic crystal for simultaneously measuring an electric field in three directions. By providing three light beams aligned along specific crystallographic directions and having specific polarizations, the crystal can simultaneously sense the electric field in three orthogonal directions. The crystal preferably has cubic symmetry and belongs to one of the point groups 43m or 23, such as crystals of bismuth silicon oxide or bismuth germanium oxide.

Abstract: An electrically controlled optical switch uses an electro-optic crystal of the type having at least one set of fast and slow optical axes. The crystal exhibits electric field induced birefringence such that a plane of polarization oriented along a first direction of a light beam passing through the crystal may be switched to a plane of polarization oriented along a second direction. A beam splitting polarizer means is disposed at one end of the crystal and directs a light beam passing through the crystal whose plane of polarization is oriented along the first direction differently from a light beam having a plane of polarization oriented along the second direction. The electro-optic crystal may be chosen from the crystal classes 43m, 42m, and 23. In a preferred embodiment, the electro-optic crystal is a bismuth germanium oxide crystal or a bismuth silicon oxide crystal.

Abstract: Process for forming tubular microstructures having predetermined shape and dimension from surfactants comprising the steps of selecting a lipid which self-aggregates into a tubular microstructure; selecting a lipid solvating organic solvent in which tubules may form; removing trace water from the selected organic solvent; dissolving the selected lipid in the dried organic solvent; allowing the dissolved lipid to grow into tubular microstructures in the dried organic solvent for a selected period of time and at a temperature below the melting point of the selected lipid.

Abstract: An electrically controlled optical switch employs an electro-optical crystal of the kind exhibiting birefringence in each of two different light paths when the crystal is disposed in orthogonally oriented electric fields, with each light path being sensitive to a different one of the two electric fields and each path having its own set of fast and slow axes. A crystal of bismuth germanium oxide has those properties. Electrodes are provided for separately establishing each of the two electric fields and control circuitry allows only one field at a time to be established. Polarizers are situated at opposite ends of the electro-optical crystal in alignment with each of the two paths. Adjacent one end of the crystal are disposed a beam splitter and a right angle prism.

Abstract: A highly-sensitive, physically small and rugged magnetometer employs a magnetostrictive amorphous metal ribbon core. A piezoelectric driver induces stress variations in the ribbon of a magnitude determined by an external magnetic field. The amplitude of the variations in magnetization is sensed by a pick-up winding disposed around the ribbon core. The dynamic range of the device is improved by employing a nulling field winding around the core to continuously null out the magnetization of the core. In contrast to the non-linear characteristic of the conventional fluxgate magnetometer, the invention provides a linear response to magnetic field strength which simplifies the processing circuitry. In addition, the ribbon may be field-annealed to improve the sensitivity of the device.

Abstract: In a method of evaluating the thermal stability of hydrocarbon liquid fuels, the fuel flows over a heated tube that causes the fuel to decompose and deposit a residue as a film on the surface of the heated tube. The thickness of that residue film is a measure of the fuel's thermal stability. To measure the film's thickness, the film is illuminated with light that is substantially monochromatic. The light reflected from the surface of the heater tube interferes with the light reflected from the overlying surface of the residue film on that tube and thereby causes variations in the intensity of the reflected light. Those variations in intensity of the reflected light are detected to obtain a measure of the thickness of the film. In one embodiment of the invention, the heated tube is situated in an enclosed housing through which the fuel is caused to flow and the thickness measurement is made while the film builds up on the heated tube.