USA As Represented by Secretary of the Navy

Geo-centers, Inc.

Naval Research Laboratory

Thomas L Fare

Frances S Ligler

David A Stenger

Jacque H Georger, Jr

Paul P Bey, Jr

Jawad Naciri

Ranganathan Shashidhar

David J Yonce

Sebastian Pfeiffer

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.

Deep ultraviolet photolithographically defined ultra-thin films for

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.

Autonulling DC bridge for real-time sensor transduction and voltage

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.

Device for low electric-field induced switching of Langmuir-Blodgett

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.

Autonulling AC bridge using differential and integration feedback

This invention relates to a semiconductor substrate having a porous surface nd to the amperometric receptor-based sensors formed with the substrate. More specifically, this invention pertains to the substrate in the form of a bipolar junction transistor having a porous hydrophilic surface directly on its base wherein the surface forms a support for an amperometric sensor. The invention also pertains to the methods of making and using the substrate and sensor.

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Washington, DC, United States of America

Thomas L Fare