42,745 research outputs found

    Field-sequential stereo television

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    System includes viewing devices that provide low interference to normal vision. It provides stereo display observable from broader area. Left and right video cameras are focused on object. Output signals from cameras are time provided by each camera. Multiplexed signal, fed to standard television monitor, displays left and right images of object

    100th Anniversary of Macromolecular Science Viewpoint: Opportunities in the Physics of Sequence-Defined Polymers

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    Polymer science has been driven by ever-increasing molecular complexity, as polymer synthesis expands an already-vast palette of chemical and architectural parameter space. Copolymers represent a key example, where simple homopolymers have given rise to random, alternating, gradient, and block copolymers. Polymer physics has provided the insight needed to explore this monomer sequence parameter space. The future of polymer science, however, must contend with further increases in monomer precision, as this class of macromolecules moves ever closer to the sequence-monodisperse polymers that are the workhorses of biology. The advent of sequence-defined polymers gives rise to opportunities for material design, with increasing levels of chemical information being incorporated into long-chain molecules; however, this also raises questions that polymer physics must address. What properties uniquely emerge from sequence-definition? Is this circumstance-dependent? How do we define and think about sequence dispersity? How do we think about a hierarchy of sequence effects? Are more sophisticated characterization methods, as well as theoretical and computational tools, needed to understand this class of macromolecules? The answers to these questions touch on many difficult scientific challenges, setting the stage for a rich future for sequence-defined polymers in polymer physics

    Concept report: Microprocessor control of electrical power system

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    An electrical power system which uses a microprocessor for systems control and monitoring is described. The microprocessor controlled system permits real time modification of system parameters for optimizing a system configuration, especially in the event of an anomaly. By reducing the components count, the assembling and testing of the unit is simplified, and reliability is increased. A resuable modular power conversion system capable of satisfying a large percentage of space applications requirements is examined along with the programmable power processor. The PC global controller which handles systems control and external communication is analyzed, and a software description is given. A systems application summary is also included

    DYNAMIC INPUT DEMAND FUNCTIONS AND RESOURCE ADJUSTMENT FOR U.S. AGRICULTURE: STATE EVIDENCE

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    The paper presents an econometric model of dynamic agricultural input demand functions that includes research based technical change and autoregressive disturbances and fits the model to data for a set of state aggregates pooled over 1950-82. The methodological approach is one of developing a theoretical foundation for a dynamic input demand system and accepting state aggregate behavior as approximated by nonlinear adjustment costs and long-term profit maximization. Although other studies have largely ignored autocorrelation in dynamic input demand systems, the results show shorter adjustment lags with autocorrelation than without autocorrelation. Dynamic input demand own-price elasticities for six input groups are inelastic, and the demand functions poses significant cross-price and research stock effects.

    Optical conversion method

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    An optical pickup comprising an electrooptical device located between two crossed polarizing devices all positioned along a common optical axis is described for switching a TV system between a color mode and a black and white mode. Embodiments in which the electrooptical system is used as a neutral density filter, a selective color filter, or a light shutter as applied to a television camera are described. Where the optical system is used as a selective color filter to produce light beams of alternating color in a field sequential color television system, deactivation of the optical system renders the television a black and white system

    National Policy and the Community Development Corporation

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    Hulme: Ten years on

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    ERS Farm Typology for a Diverse Agricultural Sector

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    The Economic Research Service (ERS) developed a farm typology which categorizes farms into more homogeneous groups than do classifications based on sales volume alone, producing a more effective policy development tool. The typology is used to describe U.S. farms.Farm Management,

    National Space Science Data Center data archive and distribution service (NDADS) automated retrieval mail system user's guide

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    The National Space Science Data Center (NSSDC) has developed an automated data retrieval request service utilizing our Data Archive and Distribution Service (NDADS) computer system. NDADS currently has selected project data written to optical disk platters with the disks residing in a robotic 'jukebox' near-line environment. This allows for rapid and automated access to the data with no staff intervention required. There are also automated help information and user services available that can be accessed. The request system permits an average-size data request to be completed within minutes of the request being sent to NSSDC. A mail message, in the format described in this document, retrieves the data and can send it to a remote site. Also listed in this document are the data currently available
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