30 research outputs found

    Travelling Waves in Distributed Control

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    Katedra řídicí technik

    Proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress

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    Published proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress, hosted by York University, 27-30 May 2018

    Simulation and control of electron and nuclear dynamics with strong and ultrashort laser pulses

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    Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Químicas, Departamento de Química Física I, leída el 28/10/2016. Tesis formato europeo (compendio de artículos)Comprender la estructura y la dinámica de los procesos químicos a nivel molecular es un paso clave para el diseño de materiales con propiedades deseadas o para el control de las reacciones químicas. Desde los inicios de la mecánica cuática, el control de los fénomenos cuánticos ha sido uno de los principales objetivos en el campo de la física y la química. El desanollo de los láseres ultrarrápidos y ultraintensos ha permitido el uso de pulsos externos, no sólo para seguir el movimiento nuclear y electrónico [ 1-3], sino también para controlarlo de forma activa, es decir, manipular la dinámica molecular en la escala de tiempos en la que ocurren los procesos físicos y químicos, así como resolver las ecuaciones dinámicas que los gobiernan, de forma que pueda favorecerse un tipo de proceso en particular [4]. De esta forma, el campo de Control Cuántico (o coherente) se ha desarrollado conjuntamente con la Femtoquímica y la Attofísica. Las primeras propuestas de control surgieron independientemente con dos escenarios. Por un lado, Tannor y Rice propusieron un mecanismo de control en la variable temporal: el esquema pump-dump [5, 6], que es un precursor de lo que se llamaría control óptimo. Por otro lado, Brumer y Shapiro [7,8] propusieron un esquema de control coherente o resuelto en frecuencias. Sin embargo, estos esquemas sólo permiten el control de forma eficiente cuando se conocen el Hamiltoniano molecular y las superficies de energía potencial. Por ejemplo, en el esquema de Brumer y Shapiro, el mismo estado intermedio puede dar lugar a diferentes productos de reacción. En el esquema pump-dump, sólo es posible el control de transiciones verticales (ventana Frank-Condon) entre estados electrónicos...Understanding the structure and dynamics of chemical processes at the molecular level is a key step toward the design of materials with the desired properties, or the efficient control of chemical reactions. Many subtleties involving basic quantum properties, such as superposition of states and interfering pathways allow to highly increase the yield of a specific process, far beyond what the probability distribution would suggest, should it follow the classical rules of motion. The spectra of molecules is one of the strongest evidence of this phenomena. Rather than distributing its energy in a continuous way along the molecule, one can find resonances that relate to particular structures. The playground of quantum dynamics offers more spectacular predictions. Using the quantum correlations at our advantage, one can externally drive a molecule toward selecting specific states or chemical processes from the huge pool of competing processes that are energetically available. Much of the history of the probe and control of chemical processes has come side-byside with the development of lasers. As we will see, one can arguably relate this history as a process. The laser was first used as a tool to ignite and selectively probe specific states and processes given its fine-tunability and intensity. ·with ultrashort laser pulses came the first probe and control of the dynamics. Pulse shaping then allowed to promote the laser to the role of a chemical agent, using Rabitz's terminology [16]. Finally, the use of very strong non-resonant pulses is promoting the laser to the role of a catalyst. Obviously, all the different roles are still being enacted by the laser depending on the particular use we need. We will now review in more detail what particular features of lasers are mainly used and how they were developed in order to fullfil the different roles of igniting, probing, "reacting" with molecules, and "catalyzing" chemical processes...Depto. de Química FísicaFac. de Ciencias QuímicasTRUEunpu

    NASA patent abstracts bibliography: A continuing bibliography. Section 2: Indexes (supplement 42)

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    A subject index is provided for over 4900 patents and patent applications for the period May 1969 through December 1992. Additional indexes list personal authors, corporate authors, contract numbers, NASA case numbers, U.S. patent class numbers, U.S. patent numbers, and NASA accession numbers

    NASA patent abstracts bibliography: A continuing bibliography. Section 2: Indexes (supplement 36)

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    A subject index is provided for over 4600 patents and patent applications for the period May 1969 through December 1989. Additional indexes list personal authors, corporate authors, contract numbers, NASA case numbers, U.S. patent class numbers, U.S. patent numbers, and NASA accession numbers

    NASA patent abstracts bibliography: A continuing bibliography. Section 2: Indexes (supplement 41)

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    A subject index is provided for over 5200 patents and patent applications for the period May 1969 through June 1992. Additional indexes list personal authors, corporate authors, contract numbers, NASA case numbers, U.S. patent class numbers, U.S. patent numbers, and NASA accession numbers

    NASA patent abstracts bibliography: A continuing bibliography. Section 2: Indexes (supplement 44)

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    A subject index is provided for over 5500 patents and patent applications for the period May 1969 through December 1993. Additional indexes list personal authors, corporate authors, contract numbers, NASA case numbers, U.S. patent class numbers, U.S. patent numbers, and NASA accession numbers

    NASA patent abstracts bibliography: A continuing bibliography. Section 2: Indexes (supplement 39)

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    A subject index is provided for over 5000 patents and patent applications for the period May 1969 through June 1991. Additional indexes list personal authors, corporate authors, contract numbers, NASA case numbers, U.S. patent class numbers, U.S. patent numbers, and NASA accession numbers

    NASA patent abstracts bibliography: A continuing bibliography. Section 2: Indexes (supplement 34)

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    A subject index is provided for over 4600 patents and patent applications for the period May 1969 through December 1988. Additional indexes list personal authors, corporate authors, contract numbers, NASA case numbers, U.S. patent class numbers, U.S. patent numbers, and NASA accession numbers
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