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Sample records for switchable ultrastrong coupling

  1. Tunable coupling and ultrastrong interaction in circuit quantum electrodynamics

    International Nuclear Information System (INIS)

    Baust, Alexander Theodor

    2015-01-01

    For future quantum information and quantum simulation architectures with superconducting circuits, a profound understanding of the coupling mechanisms between the individual building blocks is essential. In our work, we investigate galvanically coupled qubit-resonator systems, demonstrate the phenomenon of ultrastrong coupling and realize qubit mediated tunable and switchable coupling between two frequency-degenerate coplanar microwave resonators.

  2. Multiple Rabi Splittings under Ultrastrong Vibrational Coupling.

    Science.gov (United States)

    George, Jino; Chervy, Thibault; Shalabney, Atef; Devaux, Eloïse; Hiura, Hidefumi; Genet, Cyriaque; Ebbesen, Thomas W

    2016-10-07

    From the high vibrational dipolar strength offered by molecular liquids, we demonstrate that a molecular vibration can be ultrastrongly coupled to multiple IR cavity modes, with Rabi splittings reaching 24% of the vibration frequencies. As a proof of the ultrastrong coupling regime, our experimental data unambiguously reveal the contributions to the polaritonic dynamics coming from the antiresonant terms in the interaction energy and from the dipolar self-energy of the molecular vibrations themselves. In particular, we measure the opening of a genuine vibrational polaritonic band gap of ca. 60 meV. We also demonstrate that the multimode splitting effect defines a whole vibrational ladder of heavy polaritonic states perfectly resolved. These findings reveal the broad possibilities in the vibrational ultrastrong coupling regime which impact both the optical and the molecular properties of such coupled systems, in particular, in the context of mode-selective chemistry.

  3. Reversible switching of ultrastrong light-molecule coupling

    DEFF Research Database (Denmark)

    Schwartz, T; Hutchison, J A; Genet, C

    2011-01-01

    We demonstrate that photochromic molecules enable switching from the weak- to ultrastrong-coupling regime reversibly, by using all-optical control. This switch is achieved by photochemically inducing conformational changes in the molecule. Remarkably, a Rabi splitting of 700 meV is measured at room...

  4. Scalable quantum memory in the ultrastrong coupling regime.

    Science.gov (United States)

    Kyaw, T H; Felicetti, S; Romero, G; Solano, E; Kwek, L-C

    2015-03-02

    Circuit quantum electrodynamics, consisting of superconducting artificial atoms coupled to on-chip resonators, represents a prime candidate to implement the scalable quantum computing architecture because of the presence of good tunability and controllability. Furthermore, recent advances have pushed the technology towards the ultrastrong coupling regime of light-matter interaction, where the qubit-resonator coupling strength reaches a considerable fraction of the resonator frequency. Here, we propose a qubit-resonator system operating in that regime, as a quantum memory device and study the storage and retrieval of quantum information in and from the Z2 parity-protected quantum memory, within experimentally feasible schemes. We are also convinced that our proposal might pave a way to realize a scalable quantum random-access memory due to its fast storage and readout performances.

  5. Multiphoton dynamics of qutrits in the ultrastrong coupling regime with a quantized photonic field

    Energy Technology Data Exchange (ETDEWEB)

    Avetissian, H. K., E-mail: avetissian@ysu.am; Avetissian, A. K.; Mkrtchian, G. F. [Yerevan State University 0025, Center of Strong Fields Physics (Armenia); Kibis, O. V. [Novosibirsk State Technical University, Department of Applied and Theoretical Physics (Russian Federation)

    2015-12-15

    Multiphoton resonant excitation of a three-state quantum system (a qutrit) with a single-mode photonic field is considered in the ultrastrong coupling regime, when the qutrit–photonic field coupling rate is comparable to appreciable fractions of the photon frequency. For ultrastrong couplings, the obtained solutions of the Schrödinger equation that reveal multiphoton Rabi oscillations in qutrits with the interference effects leading to the collapse and revival of atomic excitation probabilities at the direct multiphoton resonant transitions.

  6. From strong to ultrastrong coupling in circuit QED architectures

    International Nuclear Information System (INIS)

    Niemczyk, Thomas

    2011-01-01

    The field of cavity quantum electrodynamics (cavity QED) studies the interaction between light and matter on a fundamental level: a single atom interacts with a single photon. If the atom-photon coupling is larger than any dissipative effects, the system enters the strong-coupling limit. A peculiarity of this regime is the possibility to form coherent superpositions of light and matter excitations - a kind of 'molecule' consisting of an atomic and a photonic contribution. The novel research field of circuit QED extends cavity QED concepts to solid-state based system. Here, a superconducting quantum bit is coupled to an on-chip superconducting one-dimensional waveguide resonator. Owing to the small mode-volume of the resonant cavity, the large dipole moment of the 'artificial atom' and the enormous engineering potential inherent to superconducting quantum circuits, remarkable atom-photon coupling strengths can be realized. This thesis describes the theoretical framework, the development of fabrication techniques and the implementation of experimental characterization techniques for superconducting quantum circuits for circuit QED applications. In particular, we study the interaction between superconducting flux quantum bits and high-quality coplanar waveguide resonators in the strong-coupling limit. Furthermore, we report on the first experimental realization of a circuit QED system operating in the ultrastrong-coupling regime, where the atom-photon coupling rate reaches a considerable fraction of the relevant system frequencies. In these experiments we could observe phenomena that can not be explained within the renowned Jaynes-Cummings model. (orig.)

  7. From strong to ultrastrong coupling in circuit QED architectures

    Energy Technology Data Exchange (ETDEWEB)

    Niemczyk, Thomas

    2011-08-10

    The field of cavity quantum electrodynamics (cavity QED) studies the interaction between light and matter on a fundamental level: a single atom interacts with a single photon. If the atom-photon coupling is larger than any dissipative effects, the system enters the strong-coupling limit. A peculiarity of this regime is the possibility to form coherent superpositions of light and matter excitations - a kind of 'molecule' consisting of an atomic and a photonic contribution. The novel research field of circuit QED extends cavity QED concepts to solid-state based system. Here, a superconducting quantum bit is coupled to an on-chip superconducting one-dimensional waveguide resonator. Owing to the small mode-volume of the resonant cavity, the large dipole moment of the 'artificial atom' and the enormous engineering potential inherent to superconducting quantum circuits, remarkable atom-photon coupling strengths can be realized. This thesis describes the theoretical framework, the development of fabrication techniques and the implementation of experimental characterization techniques for superconducting quantum circuits for circuit QED applications. In particular, we study the interaction between superconducting flux quantum bits and high-quality coplanar waveguide resonators in the strong-coupling limit. Furthermore, we report on the first experimental realization of a circuit QED system operating in the ultrastrong-coupling regime, where the atom-photon coupling rate reaches a considerable fraction of the relevant system frequencies. In these experiments we could observe phenomena that can not be explained within the renowned Jaynes-Cummings model. (orig.)

  8. Quantum Simulation of the Ultrastrong-Coupling Dynamics in Circuit Quantum Electrodynamics

    Directory of Open Access Journals (Sweden)

    D. Ballester

    2012-05-01

    Full Text Available We propose a method to get experimental access to the physics of the ultrastrong- and deep-strong-coupling regimes of light-matter interaction through the quantum simulation of their dynamics in standard circuit QED. The method makes use of a two-tone driving scheme, using state-of-the-art circuit-QED technology, and can be easily extended to general cavity-QED setups. We provide examples of ultrastrong- and deep-strong-coupling quantum effects that would be otherwise inaccessible.

  9. Analog quantum simulation of the Rabi model in the ultra-strong coupling regime.

    Science.gov (United States)

    Braumüller, Jochen; Marthaler, Michael; Schneider, Andre; Stehli, Alexander; Rotzinger, Hannes; Weides, Martin; Ustinov, Alexey V

    2017-10-03

    The quantum Rabi model describes the fundamental mechanism of light-matter interaction. It consists of a two-level atom or qubit coupled to a quantized harmonic mode via a transversal interaction. In the weak coupling regime, it reduces to the well-known Jaynes-Cummings model by applying a rotating wave approximation. The rotating wave approximation breaks down in the ultra-strong coupling regime, where the effective coupling strength g is comparable to the energy ω of the bosonic mode, and remarkable features in the system dynamics are revealed. Here we demonstrate an analog quantum simulation of an effective quantum Rabi model in the ultra-strong coupling regime, achieving a relative coupling ratio of g/ω ~ 0.6. The quantum hardware of the simulator is a superconducting circuit embedded in a cQED setup. We observe fast and periodic quantum state collapses and revivals of the initial qubit state, being the most distinct signature of the synthesized model.An analog quantum simulation scheme has been explored with a quantum hardware based on a superconducting circuit. Here the authors investigate the time evolution of the quantum Rabi model at ultra-strong coupling conditions, which is synthesized by slowing down the system dynamics in an effective frame.

  10. Polariton Resonances for Ultrastrong Coupling Cavity Optomechanics in GaAs/AlAs Multiple Quantum Wells.

    Science.gov (United States)

    Jusserand, B; Poddubny, A N; Poshakinskiy, A V; Fainstein, A; Lemaitre, A

    2015-12-31

    Polariton-mediated light-sound interaction is investigated through resonant Brillouin scattering experiments in GaAs/AlAs multiple-quantum wells. Photoelastic coupling enhancement at exciton-polariton resonance reaches 10(5) at 30 K as compared to a typical bulk solid room temperature transparency value. When applied to GaAs based cavity optomechanical nanodevices, this result opens the path to huge displacement sensitivities and to ultrastrong coupling regimes in cavity optomechanics with couplings g(0) in the range of 100 GHz.

  11. Multi-mode ultra-strong coupling in circuit quantum electrodynamics

    Science.gov (United States)

    Bosman, Sal J.; Gely, Mario F.; Singh, Vibhor; Bruno, Alessandro; Bothner, Daniel; Steele, Gary A.

    2017-10-01

    With the introduction of superconducting circuits into the field of quantum optics, many experimental demonstrations of the quantum physics of an artificial atom coupled to a single-mode light field have been realized. Engineering such quantum systems offers the opportunity to explore extreme regimes of light-matter interaction that are inaccessible with natural systems. For instance the coupling strength g can be increased until it is comparable with the atomic or mode frequency ωa,m and the atom can be coupled to multiple modes which has always challenged our understanding of light-matter interaction. Here, we experimentally realize a transmon qubit in the ultra-strong coupling regime, reaching coupling ratios of g/ωm = 0.19 and we measure multi-mode interactions through a hybridization of the qubit up to the fifth mode of the resonator. This is enabled by a qubit with 88% of its capacitance formed by a vacuum-gap capacitance with the center conductor of a coplanar waveguide resonator. In addition to potential applications in quantum information technologies due to its small size, this architecture offers the potential to further explore the regime of multi-mode ultra-strong coupling.

  12. Few-Electron Ultrastrong Light-Matter Coupling in a Quantum LC Circuit

    Directory of Open Access Journals (Sweden)

    Yanko Todorov

    2014-11-01

    Full Text Available The phenomenon of ultrastrong light-matter interaction of a two-dimensional electron gas within a lumped element electronic circuit resonator is explored. The gas is coupled through the oscillating electric field of the capacitor, and in the limit of very small capacitor volumes, the total number of electrons of the system can be reduced to only a few. One of the peculiar features of our quantum mechanical system is that its Hamiltonian evolves from the fermionic Rabi model to the bosonic Hopfield model for light-matter coupling as the number of electrons is increased. We show that the Dicke states, introduced to describe the atomic super-radiance, are the natural base to describe the crossover between the two models. Furthermore, we illustrate how the ultrastrong coupling regime in the system and the associated antiresonant terms of the quantum Hamiltonian have a fundamentally different impact in the fermionic and bosonic cases. In the intermediate regime, our system behaves like a multilevel quantum bit with nonharmonic energy spacing, owing to the particle-particle interactions. Such a system can be inserted into a technological semiconductor platform, thus opening interesting perspectives for electronic devices where the readout of quantum electrodynamical properties is obtained via the measure of a DC current.

  13. Low-voltage polariton electroluminescence from an ultrastrongly coupled organic light-emitting diode

    Energy Technology Data Exchange (ETDEWEB)

    Gubbin, Christopher R.; Maier, Stefan A. [Experimental Solid State Group, Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom); Kéna-Cohen, Stéphane, E-mail: s.kena-cohen@polymtl.ca [Department of Engineering Physics, École Polytechnique de Montréal, Montréal, Quebec H3C 3A7 (Canada)

    2014-06-09

    We demonstrate electroluminescence from Frenkel molecular excitons ultrastrongly coupled to photons of a metal-clad microcavity containing a 2,7-bis[9,9-di(4-methylphenyl)-fluoren-2-yl]-9,9-di(4-methylphenyl)fluorene emissive layer. Thin layers of molybdenum oxide and 4,7-diphenyl-1,10-phenanthroline are used as hole and electron injection layers, respectively. The fabricated devices exhibit an electroluminescence threshold of 3.1 V, a value that is below the bare exciton energy. This result is found to be independent of detuning and consistent with a two-step process for polariton formation. Moreover, we investigate the quantum efficiency of carrier to polariton to photon conversion and obtain an external quantum efficiency of 0.1% for the fabricated structures, an improvement of 5 orders of magnitude over previous reports.

  14. Long-lasting quantum memories: Extending the coherence time of superconducting artificial atoms in the ultrastrong-coupling regime

    Science.gov (United States)

    Stassi, Roberto; Nori, Franco

    2018-03-01

    Quantum systems are affected by interactions with their environments, causing decoherence through two processes: pure dephasing and energy relaxation. For quantum information processing it is important to increase the coherence time of Josephson qubits and other artificial two-level atoms. We show theoretically that if the coupling between these qubits and a cavity field is longitudinal and in the ultrastrong-coupling regime, the system is strongly protected against relaxation. Vice versa, if the coupling is transverse and in the ultrastrong-coupling regime, the system is protected against pure dephasing. Taking advantage of the relaxation suppression, we show that it is possible to enhance their coherence time and use these qubits as quantum memories. Indeed, to preserve the coherence from pure dephasing, we prove that it is possible to apply dynamical decoupling. We also use an auxiliary atomic level to store and retrieve quantum information.

  15. Qubit-oscillator systems in the ultrastrong-coupling regime and their potential for preparing nonclassical states

    Science.gov (United States)

    Nori, Franco; Ashhab, Sahel

    2011-03-01

    We consider a system composed of a two-level system (i.e. a qubit) and a harmonic oscillator in the ultrastrong-coupling regime, where the coupling strength is comparable to the qubit and oscillator energy scales. We explore the possibility of preparing nonclassical states in this system, especially in the ground state of the combined system. The nonclassical states that we consider include squeezed states, Schrodinger-cat states and entangled states. We also analyze the nature of the change in the ground state as the coupling strength is increased, going from a separable ground state in the absence of coupling to a highly entangled ground state in the case of very strong coupling. Reference: S. Ashhab and F. Nori, Phys. Rev. A 81, 042311 (2010). We thank support from DARPA, AFOSR, NSA, LPS, ARO, NSF, MEXT, JSPS, FIRST, and JST.

  16. Plasma-based localized defect for switchable coupling applications

    International Nuclear Information System (INIS)

    Varault, Stefan; Gabard, Benjamin; Sokoloff, Jerome; Bolioli, Sylvain

    2011-01-01

    We report in this paper experimental measurements in order to validate the concept of switchable electromagnetic band gap filters based on plasma capillaries in the microwave regime. The plasma tube is embedded inside the structure to create a bistable (plasma on or off) punctual defect. We first investigate two kinds of discharge tubes: Ar-Hg and pure Ne, which we then use to experimentally achieve plasma-based reconfigurable applications, namely, a two-port coupler and a two-port demultiplexer.

  17. Gate and magnetic field tunable ultrastrong coupling between a magnetoplasmon and the optical mode of an LC cavity

    Science.gov (United States)

    Paravicini-Bagliani, Gian L.; Scalari, Giacomo; Valmorra, Federico; Keller, Janine; Maissen, Curdin; Beck, Mattias; Faist, Jérôme

    2017-05-01

    The coupling between the optical mode of an LC cavity and a magnetoplasmon is studied by terahertz transmission spectroscopy. The magnetoplasmons are created by etching a high-mobility two-dimensional electron gas into stripes. As a result, we identify three different regimes, depending on the plasmon frequency relative to the cavity frequency. We find a significant coupling to the cyclotron dispersion even in presence of screening of the electric field by the plasmon.

  18. Ultrastrong light-matter coupling at terahertz frequencies with split ring resonators and inter-Landau level transitions

    Science.gov (United States)

    Scalari, G.; Maissen, C.; Hagenmüller, D.; De Liberato, S.; Ciuti, C.; Reichl, C.; Wegscheider, W.; Schuh, D.; Beck, M.; Faist, J.

    2013-04-01

    We study strong light-matter coupling at terahertz frequencies employing a system based on an array of deeply subwavelength split ring resonators deposited on top of an ensemble of modulation-doped quantum wells. By applying a magnetic field parallel to the epitaxial growth axis, at low temperatures, Landau Levels are formed. We probe the interaction of the inter-Landau level transitions with the resonators modes, measuring a normalized coupling ratio Ω/ωc=0.58 between the inter-Landau level frequency ωc and the Rabi frequency Ω of the system. The physics of the system is studied as a function of the metasurface composition and of the number of quantum wells. We demonstrate that the light-matter coupling strength is basically independent from the metamaterial lattice spacing.

  19. Observing pure effects of counter-rotating terms without ultrastrong coupling: A single photon can simultaneously excite two qubits

    Science.gov (United States)

    Wang, Xin; Miranowicz, Adam; Li, Hong-Rong; Nori, Franco

    2017-12-01

    The coherent process that a single photon simultaneously excites two qubits has recently been theoretically predicted by Garziano et al. [L. Garziano, V. Macrì, R. Stassi, O. Di Stefano, F. Nori, and S. Savasta, One Photon Can Simultaneously Excite two or More Atoms, Phys. Rev. Lett. 117, 043601 (2016), 10.1103/PhysRevLett.117.043601]. We propose a different approach to observe a similar dynamical process based on a superconducting quantum circuit, where two coupled flux qubits longitudinally interact with the same resonator. We show that this simultaneous excitation of two qubits (assuming that the sum of their transition frequencies is close to the cavity frequency) is related to the counter-rotating terms in the dipole-dipole coupling between two qubits, and the standard rotating-wave approximation is not valid here. By numerically simulating the adiabatic Landau-Zener transition and Rabi-oscillation effects, we clearly verify that the energy of a single photon can excite two qubits via higher-order transitions induced by the longitudinal couplings and the counter-rotating terms. Compared with previous studies, the coherent dynamics in our system only involves one intermediate state and, thus, exhibits a much faster rate. We also find transition paths which can interfere. Finally, by discussing how to control the two longitudinal-coupling strengths, we find a method to observe both constructive and destructive interference phenomena in our system.

  20. Integrated power-heat-cold-coupling by switchable Stirling-Vuilleumier-Hybrid-Machines

    International Nuclear Information System (INIS)

    Kuehl, Hans-Detlev

    2017-01-01

    A Stirling engine consists in its so-called Gamma type on the one hand of a thermal compressor in which a double-acting displacer is the working gas between a ''hot'' and a ''warm'' (ie located on the heat use temperature level of the CHP application) cylinder chamber isochoric via a regenerator periodically shuffled back and forth. On the other hand, he has a spatially separated, one-sided working piston-cylinder system, which is connected to the ''warm'' side of the thermal compressor through an overflow and thus is at a similar temperature level. If an additional regenerator is inserted into this overflow channel, then the temperature levels are separated, since the heat output of the process takes place primarily via the warm cylinder space of the displacer system, while the cylinder space of the working piston constitutes a heat sink. This so-called ''hybrid'' process is still characterized by a - compared to the Stirling mode only slightly reduced - mechanical power output, but in addition by a theoretically equal to this magnitude, recorded on the cylinder at ''cold'' temperature cooling capacity, It thus represents an integrated system for power-heat-cold-coupling, which can be realized by a single thermodynamic process. Turning this process in the warm temperature range in addition to another, lying on the back of the working cylinder cylinder space, so that the former becomes a second, double-acting displacer, we finally get the known as a thermally driven heat pump or chiller Vuilleumier process that Ideally, no mechanical power gives or absorbs. At the Chair of Thermodynamics of the TU Dortmund, a research machine was developed and measured in a meanwhile completed research project funded by the DFG, which can switch between the three described processes and thus be adapted to changing power, heat and cooling requirements. In order to reduce the

  1. Switchable capacitor

    NARCIS (Netherlands)

    Rottenberg, X.; Jansen, Henricus V.; Tilmans, H.A.C.; De Raedt, W.

    2003-01-01

    A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom elecrode, a dielaectric layer deposited on at least part of sai bottum electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to the

  2. Switchable capacitor

    NARCIS (Netherlands)

    Rottenberg, Xavier; Jansen, Henricus V.; Tilmans, H.A.C.; Tilmans, Hendrikus; De Raedt, Walter

    2011-01-01

    A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom elecrode, a dielaectric layer deposited on at least part of sai bottum electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to the

  3. Switchable lasing in multimode microcavities

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei V.; Chigrin, Dmitry N.; Lavrinenko, Andrei

    2007-01-01

    We propose the new concept of a switchable multimode microlaser. As a generic, realistic model of a multimode microresonator a system of two coupled defects in a two-dimensional photonic crystal is considered. We demonstrate theoretically that lasing of the cavity into one selected resonator mode...... in terms of the laser bistability is presented....

  4. Ultrastrong Stationary Double Layers in a Nondischarge Magnetoplasma

    DEFF Research Database (Denmark)

    Sato, N.; Hatakeyama, R.; Iizuka, S.

    1981-01-01

    Ultrastrong stationary double layers are generated in a magnetoplasma by simply applying potential differences between two plasma sources. The potential drop ϕD of the double layer is increased up to eϕD/Te≃2×103 (Te is the electron temperature in eV) with no difficulties caused by gas discharge....... There are always large spiky fluctuations on the low-potential tail of the double layers....

  5. Switchable Bragg gratings

    DEFF Research Database (Denmark)

    Marckmann, Carl Johan

    2003-01-01

    Research Center (MIC) at the Technical University of Denmark. The Bragg gratings were fabricated at COM using UV irradiation of the planar waveguides using the phase mask method. The induction of a frozen-in DC electric field into the samples was performed by thermal poling of the Bragg gratings...... layers, it becam possible to investigate the symmetry properties of the third-order nonlinearities. Contrary to the expectations for an amorphous material, the measurements indicated an almost polarization independent third-order nonlinearity - the most probable explanation being electrostriction......The subject of this ph.d. thesis was the development of an electrically switchable Bragg grating made in an optical waveguide using thermal poling to be applied within optical telecommunication systems. The planar waveguides used in this thesis were fabricated at the Micro- and Nanotechnology...

  6. Ultrastrong Bioinspired Graphene-Based Fibers via Synergistic Toughening.

    Science.gov (United States)

    Zhang, Yuanyuan; Li, Yuchen; Ming, Peng; Zhang, Qi; Liu, Tianxi; Jiang, Lei; Cheng, Qunfeng

    2016-04-13

    Ultrastrong bioinspired graphene-based fibers are designed and prepared via synergistic toughening of ionic and covalent bonding. The tensile strength reaches up to 842.6 MPa and is superior to all other reported graphene-based fibers. In addition, its electrical conductivity is as high as 292.4 S cm(-1). This bioinspired synergistic toughening strategy supplies new insight toward the construction of integrated high-performance graphene-based fibers in the near future. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Output field-quadrature measurements and squeezing in ultrastrong cavity-QED

    Science.gov (United States)

    Stassi, Roberto; Savasta, Salvatore; Garziano, Luigi; Spagnolo, Bernardo; Nori, Franco

    2016-12-01

    We study the squeezing of output quadratures of an electro-magnetic field escaping from a resonator coupled to a general quantum system with arbitrary interaction strengths. The generalized theoretical analysis of output squeezing proposed here is valid for all the interaction regimes of cavity-quantum electrodynamics: from the weak to the strong, ultrastrong, and deep coupling regimes. For coupling rates comparable or larger then the cavity resonance frequency, the standard input-output theory for optical cavities fails to calculate the variance of output field-quadratures and predicts a non-negligible amount of output squeezing, even if the system is in its ground state. Here we show that, for arbitrary interaction strength and for general cavity-embedded quantum systems, no squeezing can be found in the output-field quadratures if the system is in its ground state. We also apply the proposed theoretical approach to study the output squeezing produced by: (i) an artificial two-level atom embedded in a coherently-excited cavity; and (ii) a cascade-type three-level system interacting with a cavity field mode. In the latter case the output squeezing arises from the virtual photons of the atom-cavity dressed states. This work extends the possibility of predicting and analyzing the results of continuous-variable optical quantum-state tomography when optical resonators interact very strongly with other quantum systems.

  8. Stacked switchable element and diode combination with a low breakdown switchable element

    Science.gov (United States)

    Wang, Qi [Littleton, CO; Ward, James Scott [Englewood, CO; Hu, Jian [Englewood, CO; Branz, Howard M [Boulder, CO

    2012-06-19

    A device (10) comprises a semiconductor diode (12) and a switchable element (14) positioned in stacked adjacent relationship. The semiconductor diode (12) and the switchable element (14) are electrically connected in series with one another. The switchable element (14) is switchable from a low-conductance state to a high-conductance state in response to the application of a low-density forming current and/or a low voltage.

  9. On the strain coupling across vertical interfaces of switchable BiFeO3-CoFe2O4 multiferroic nanostructures

    Science.gov (United States)

    Dix, N.; Muralidharan, R.; Guyonnet, J.; Warot-Fonrose, B.; Varela, M.; Paruch, P.; Sánchez, F.; Fontcuberta, J.

    2009-08-01

    In magnetoelectrically coupled CoFe2O4-BiFeO3 nanostructures vertical and lateral lattice parameters of both phases are determined. We find that the in-plane lattice parameter of CoFe2O4 is fully relaxed whereas it presents compressive strain along the out-of-plane direction. Although the CoFe2O4-BiFeO3 interface is semicoherent, CoFe2O4 out-of-plane lattice strain is not relaxed after selective removal of the matrix and thus it is of nonelastic origin. In spite of the absence of elastic residual strain caused by CoFe2O4-BiFeO3 interfaces, the two phases are mechanically coupled as demonstrated by the electrical switching of the magnetization.

  10. Heat Transfer Manipulation via Switchable Wettability Surfaces

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed research seeks to manipulate heat transfer during flow condensation in low-gravity environments by employing switchable wettability surfaces....

  11. Switchable Hydrophobic-Hydrophilic Surfaces

    CERN Document Server

    Bunker, B C; Huber, D L; Kent, M S; Kushmerick, J G; Lopez, G P; Manginell, R P; Méndez, S E; Yim, H

    2002-01-01

    Tethered films of poly n-isopropylacrylamide (PNIPAM) films have been developed as materials that can be used to switch the chemistry of a surface in response to thermal activation. In water, PNIPAM exhibits a thermally-activated phase transition that is accompanied by significant changes in polymer volume, water contact angle, and protein adsorption characteristics. New synthesis routes have been developed to prepare PNIPAM films via in-situ polymerization on self-assembled monolayers. Swelling transitions in tethered films have been characterized using a wide range of techniques including surface plasmon resonance, attenuated total reflectance infrared spectroscopy, interfacial force microscopy, neutron reflectivity, and theoretical modeling. PNIPAM films have been deployed in integrated microfluidic systems. Switchable PNIPAM films have been investigated for a range of fluidic applications including fluid pumping via surface energy switching and switchable protein traps for pre-concentrating and separating...

  12. Photo-switchable membrane and method

    Science.gov (United States)

    Marshall, Kenneth L; Glowacki, Eric

    2013-05-07

    Switchable gas permeation membranes in which a photo-switchable low-molecular-weight liquid crystalline (LC) material acts as the active element, and a method of making such membranes. Different LC eutectic mixtures were doped with mesogenic azo dyes and infused into track-etched porous membranes with regular cylindrical pores. Photo-induced isothermal phase changes in the imbibed mesogenic material afforded large, reversible changes in the permeability of the photo-switchable membrane to nitrogen. For example, membranes imbibed with a photo-switchable cyanobiphenyl LC material demonstrated low permeability in the nematic state, while the photo-generated isotropic state demonstrated a 16.times.-greater sorption coefficient. Both states obey a high linear sorption behavior in accordance with Henry's Law. In contrast, membranes imbibed with a photo-switchable phenyl benzoate LC material showed the opposite permeability behavior to the biphenyl-imbibed membrane, along with nonlinear sorption behavior.

  13. Switchable bio-inspired adhesives

    Science.gov (United States)

    Kroner, Elmar

    2015-03-01

    Geckos have astonishing climbing abilities. They can adhere to almost any surface and can run on walls and even stick to ceilings. The extraordinary adhesion performance is caused by a combination of a complex surface pattern on their toes and the biomechanics of its movement. These biological dry adhesives have been intensely investigated during recent years because of the unique combination of adhesive properties. They provide high adhesion, allow for easy detachment, can be removed residue-free, and have self-cleaning properties. Many aspects have been successfully mimicked, leading to artificial, bio-inspired, patterned dry adhesives, and were addressed and in some aspects they even outperform the adhesion capabilities of geckos. However, designing artificial patterned adhesion systems with switchable adhesion remains a big challenge; the gecko's adhesion system is based on a complex hierarchical surface structure and on advanced biomechanics, which are both difficult to mimic. In this paper, two approaches are presented to achieve switchable adhesion. The first approach is based on a patterned polydimethylsiloxane (PDMS) polymer, where adhesion can be switched on and off by applying a low and a high compressive preload. The switch in adhesion is caused by a reversible mechanical instability of the adhesive silicone structures. The second approach is based on a composite material consisting of a Nickel- Titanium (NiTi) shape memory alloy and a patterned adhesive PDMS layer. The NiTi alloy is trained to change its surface topography as a function of temperature, which results in a change of the contact area and of alignment of the adhesive pattern towards a substrate, leading to switchable adhesion. These examples show that the unique properties of bio-inspired adhesives can be greatly improved by new concepts such as mechanical instability or by the use of active materials which react to external stimuli.

  14. Ferroelectric nanostructure having switchable multi-stable vortex states

    Science.gov (United States)

    Naumov, Ivan I [Fayetteville, AR; Bellaiche, Laurent M [Fayetteville, AR; Prosandeev, Sergey A [Fayetteville, AR; Ponomareva, Inna V [Fayetteville, AR; Kornev, Igor A [Fayetteville, AR

    2009-09-22

    A ferroelectric nanostructure formed as a low dimensional nano-scale ferroelectric material having at least one vortex ring of polarization generating an ordered toroid moment switchable between multi-stable states. A stress-free ferroelectric nanodot under open-circuit-like electrical boundary conditions maintains such a vortex structure for their local dipoles when subject to a transverse inhomogeneous static electric field controlling the direction of the macroscopic toroidal moment. Stress is also capable of controlling the vortex's chirality, because of the electromechanical coupling that exists in ferroelectric nanodots.

  15. Safer Battery with Switchable Polymer Coating Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) proposes to utilize a switchable polymer (SWP) to prevent catastrophic failure due to internal shorting or overdischarge in lithium-ion...

  16. Ionization, photoelectron dynamics and elastic scattering in relativistic, ultra-strong field

    Science.gov (United States)

    Luo, Sui

    Ultrastrong laser-matter interaction has direct bearing to next generation technologies including plasma acceleration, laser fusion and attosecond X-ray generation. The commonly known physics in strong field becomes different as one progress to ultrastrong field. The works presented in this dissertation theoretically study the influence of relativistic effect and magnetic component of the laser field on the ionization, photoelectron dynamics and elastic scattering processes. The influence of magnetic component (B laser) of circularly polarized (CP) ultrastrong fields (up to3 x 1022 W/cm2) on atomic bound state dynamics is investigated. The Poincare plots are used to find the changes in trajectory energies are on the order of a few percent for intensities up to1 x 1022 W/cm2. It is found that at intensities where ionization approaches 50% for the bound state, the small changes from Blaser of the circular polarized light can actually result in a several-fold decrease in ionization probability. The force on the bound electron exerted by the Lorentz force from B laser is perpendicular to the rotating plane of the circular polarized light, and this nature makes those trajectories which are aligned away from the minimum in the potential barrier stabilized against tunneling ionization. Our results provide a classical understanding for ionization in ultrastrong fields and indicate that relativistic effects in ultrastrong field ionization may most easily be seen with CP fields. The photoelectron energy spectra from elastic rescattering in ultrastrong laser fields (up to 2x1019 W/cm2) is studied by using a relativistic adaption of a semi-classical three-step recollision model. The Hartree-Fock scattering potentials are used in calculating the elastic rescattering for both hydrogenlike and noble gas species. It is found that there is a reduction in elastic rescattering for intensities beyond 6 x 1016 W/cm2 when the laser Lorentz deflection of the photoelectron exceeds its

  17. Valuation of switchable tariff for wind energy

    International Nuclear Information System (INIS)

    Yu, Wang; Sheble, Gerald B.; Lopes, Joao A. Pecas; Matos, Manuel Antonio

    2006-01-01

    The current fixed tariff remuneration for wind energy is not compatible with the deregulation of the electric power industry. The time-varying and location-dependent value of renewable energy is not acknowledged. The newly announced switchable tariff for wind energy in the Spanish electricity market provides a promising solution to compensating renewable energy within the deregulated electric power industry. The new switchable tariff provides wind generators more flexibility in operating wind generation assets. Such flexibilities provide option value in coordinating the seasonality of wind energy, demand on electric power and electricity prices movement. This paper models and valuates the flexibility on switching tariff as real compound options for wind generators. Numerical examples valuate wind generation assets under fixed tariff, spot market price taking, and yearly and monthly switchable tariffs. The optimal switching strategies are identified. The impacts of the switchable tariff on sitting criteria and values of wind generation assets are investigated. An improvement on the yearly switchable tariff is suggested to further reduce the operation risk of wind generators and fully explore the efficiency provided by competitive electricity markets. (author)

  18. Bioinspired, Ultrastrong, Highly Biocompatible, and Bioactive Natural Polymer/Graphene Oxide Nanocomposite Films.

    Science.gov (United States)

    Zhu, Wen-Kun; Cong, Huai-Ping; Yao, Hong-Bin; Mao, Li-Bo; Asiri, Abdullah M; Alamry, Khalid A; Marwani, Hadi M; Yu, Shu-Hong

    2015-09-09

    Tough and biocompatible nanocomposite films: A new type of bioinspired ultrastrong, highly biocompatible, and bioactive konjac glucomannan (KGM)/graphene oxide (GO) nanocomposite film is fabricated on a large scale by a simple solution-casting method. Such KGM-GO composite films exhibit much enhanced mechanical properties under the strong hydrogen-bonding interactions, showing great potential in the fields of tissue engineering and food package. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. High quality factor, fully switchable terahertz superconducting metasurface

    Energy Technology Data Exchange (ETDEWEB)

    Scalari, G., E-mail: scalari@phys.ethz.ch; Maissen, C.; Faist, J. [Institute of Quantum Electronics, Eidgenössische Technische Hochschule Zürich (Switzerland); Cibella, S.; Leoni, R. [Istituto di Fotonica e Nanotecnologie (IFN), CNR, via Cineto Romano 42, 00156 Rome (Italy)

    2014-12-29

    We present a complementary THz metasurface realised with Niobium thin film which displays a quality factor Q = 54 and a fully switchable behaviour as a function of the temperature. The switching behaviour and the high quality factor are due to a careful design of the metasurface aimed at maximising the ohmic losses when the Nb is above the critical temperature and minimising the radiative coupling. The superconductor allows the operation of the cavity with high Q and the use of inductive elements with a high aspect ratio. Comparison with three dimensional finite element simulations highlights the crucial role of the inductive elements and of the kinetic inductance of the Cooper pairs in achieving the high quality factor and the high field enhancement.

  20. Wavelength switchable fiber-optic Sagnac filter

    Science.gov (United States)

    Su, Dan; Qiao, Xueguang; Rong, Qiangzhou; Shao, Zhihua

    2018-03-01

    A wavelength switchable fiber-optic comb filter based on an in-line Sagnac interference is proposed and demonstrated. The proposed filter consists of a polarizer, two polarization controllers (PCs) and two sections of polarization maintaining fiber (PMFs). The output comb spectrum characteristics of the configuration are theoretically analyzed by Jones matrix, and then numerically simulated and experimentally demonstrated, of which the results present four comb filter-types (sinusoidal, flat-top and narrow-band superposition, and line-shaped spectra) by adjusting the polarizations of light with PCs.

  1. Passband switchable microwave photonic multiband filter.

    Science.gov (United States)

    Ge, Jia; Fok, Mable P

    2015-11-02

    A reconfigurable microwave photonic (MWP) multiband filter with selectable and switchable passbands is proposed and experimentally demonstrated, with a maximum of 12 simultaneous passbands evenly distributed from 0 to 10 GHz. The scheme is based on the generation of tunable optical comb lines using a two-stage Lyot loop filter, such that various filter tap spacings and spectral combinations are obtained for the configuration of the MWP filter. Through polarization state adjustment inside the Lyot loop filter, an optical frequency comb with 12 different comb spacings is achieved, which corresponds to a MWP filter with 12 selectable passbands. Center frequencies of the filter passbands are switchable, while the number of simultaneous passbands is tunable from 1 to 12. Furthermore, the MWP multiband filter can either work as an all-block, single-band or multiband filter with various passband combinations, which provide exceptional operation flexibility. All the passbands have over 30 dB sidelobe suppression and 3-dB bandwidth of 200 MHz, providing good filter selectivity.

  2. Safer Battery with Switchable Polymer Coating, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) proposes to utilize a switchable polymer (SWP) to prevent catastrophic failure due to internal shorting or overdischarge in lithium-ion...

  3. Switchable and Tunable Aerodynamic Drag on Cylinders

    Science.gov (United States)

    Guttag, Mark; Lopéz Jiménez, Francisco; Upadhyaya, Priyank; Kumar, Shanmugam; Reis, Pedro

    We report results on the performance of Smart Morphable Surfaces (Smporhs) that can be mounted onto cylindrical structures to actively reduce their aerodynamic drag. Our system comprises of an elastomeric thin shell with a series of carefully designed subsurface cavities that, once depressurized, lead to a dramatic deformation of the surface topography, on demand. Our design is inspired by the morphology of the giant cactus (Carnegiea gigantea) which possesses an array of axial grooves, thought to help reduce aerodynamic drag, thereby enhancing the structural robustness of the plant under wind loading. We perform systematic wind tunnel tests on cylinders covered with our Smorphs and characterize their aerodynamic performance. The switchable and tunable nature of our system offers substantial advantages for aerodynamic performance when compared to static topographies, due to their operation over a wider range of flow conditions.

  4. A redox-switchable Au8-cluster sensor.

    Science.gov (United States)

    Wu, Te-Haw; Hsu, Yu-Yen; Lin, Shu-Yi

    2012-07-09

    The proof of concept of a simple sensing platform based on the fluorescence of a gold cluster consisting of eight atoms, which is easily manipulated by reduction and oxidation of a specific molecule in the absence of chemical linkers, is demonstrated. Without using any coupling reagents to arrange the distance of the donor-acceptor pair, the fluorescence of the Au(8) -cluster is immediately switched off in the presence of 2-pyridinethiol (2-PyT) quencher. Through an upward-curving Stern-Volmer plot, the system shows complex fluorescence quenching with a combination of static and dynamic quenching processes. To analyze the static quenching constant (V) by a "sphere of action" model, the collisional encounter between the Au(8) -cluster and 2-PyT presents a quenching radius (r) ≈5.8 nm, which is larger than the sum of the radii of the Au(8) -cluster and 2-PyT. This implies that fluorescence quenching can occur even though the Au(8) -cluster and 2-PyT are not very close to each other. The quenching pathway may be derived from a photoinduced electron-transfer process of the encounter pair between the Au(8) -cluster (as an electron donor) and 2-PyT (as an electron acceptor) to allow efficient fluorescence quenching in the absence of coupling reagents. Interestingly, the fluorescence is restored by oxidation of 2-PyT to form the corresponding disulfide compound and then quenched again after the reduction of the disulfide. This redox-switchable fluorescent Au(8) -cluster platform is a novel discovery, and its utility as a promising sensor for detecting H(2) O(2) -generating enzymatic transformations is demonstrated. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Photo-switchable microbial fuel-cells.

    Science.gov (United States)

    Schlesinger, Orr; Dandela, Rambabu; Bhagat, Ashok; Adepu, Raju; Meijler, Michael M; Xia, Lin; Alfonta, Lital

    2018-05-01

    Regulation of Bio-systems in a clean, simple, and efficient way is important for the design of smart bio-interfaces and bioelectronic devices. Light as a non-invasive mean to control the activity of a protein enables spatial and temporal control far superior to other chemical and physical methods. The ability to regulate the activity of a catalytic enzyme in a biofuel-cell reduces the waste of resources and energy and turns the fuel-cell into a smart and more efficient device for power generation. Here we present a microbial-fuel-cell based on a surface displayed, photo-switchable alcohol dehydrogenase. The enzyme was modified near the active site using non-canonical amino acids and a small photo-reactive molecule, which enables reversible control of enzymatic activity. Depending on the modification site, the enzyme exhibits reversible behavior upon irradiation with UV and visible light, in both biochemical, and electrochemical assays. The change observed in power output of a microbial fuel cell utilizing the modified enzyme was almost five-fold, between inactive and active states. © 2018 Wiley Periodicals, Inc.

  6. Ferroelectric based catalysis: Switchable surface chemistry

    Science.gov (United States)

    Kakekhani, Arvin; Ismail-Beigi, Sohrab

    2015-03-01

    We describe a new class of catalysts that uses an epitaxial monolayer of a transition metal oxide on a ferroelectric substrate. The ferroelectric polarization switches the surface chemistry between strongly adsorptive and strongly desorptive regimes, circumventing difficulties encountered on non-switchable catalytic surfaces where the Sabatier principle dictates a moderate surface-molecule interaction strength. This method is general and can, in principle, be applied to many reactions, and for each case the choice of the transition oxide monolayer can be optimized. Here, as a specific example, we show how simultaneous NOx direct decomposition (into N2 and O2) and CO oxidation can be achieved efficiently on CrO2 terminated PbTiO3, while circumventing oxygen (and sulfur) poisoning issues. One should note that NOx direct decomposition has been an open challenge in automotive emission control industry. Our method can expand the range of catalytically active elements to those which are not conventionally considered for catalysis and which are more economical, e.g., Cr (for NOx direct decomposition and CO oxidation) instead of canonical precious metal catalysts. Primary support from Toyota Motor Engineering and Manufacturing, North America, Inc.

  7. Effective lipid extraction from algae cultures using switchable solvents

    NARCIS (Netherlands)

    Samori, Chiara; Lopez Barreiro, D.; Vet, Robin; Pezzolesi, Laura; Brilman, Derk Willem Frederik; Galletti, Paola; Tagliavini, Emilio

    2013-01-01

    A new procedure based on switchable polarity solvents (SPS) was proposed for lipid extraction of wet algal samples or cultures, thereby circumventing the need for an energy intensive drying step and facilitating easy recovery of the lipids from the extraction liquid. Lipids were extracted by using

  8. Switchable capacitor and method of making the same

    NARCIS (Netherlands)

    Rottenberg, Xavier; Jansen, Henricus V.; Tilmans, Hendrikus; De Raedt, Walter

    2006-01-01

    A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom electrode, a dielectric layer deposited on at least part of said bottom electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to

  9. Switchable capacitor and method of making the same

    NARCIS (Netherlands)

    Rottenberg, Xavier; Jansen, Henricus V.; Tilmans, Hendrikus; De Raedt, Walter

    2003-01-01

    A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom electrode, a dielectric layer deposited on at least part of said bottom electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to

  10. Sound and Noisy Light: Tuning Phonon Modes in Photo-switchable Nanostructures

    Science.gov (United States)

    Sklan, Sophia; Grossman, Jeffrey

    2014-03-01

    The coupling of light to structural vibrations is well known and results in phenomena like phonon polaritons, acousto-optics (where phonons modulate optical properties), and optomechanics (where light creates or absorbs phonons). Here we consider the question of whether light could also be used to modulate the properties of phonons. We examine photo-isomers (which change their shape under exposure to light), embedded in a nanostructure designed to amplify the effects of photo-switching. To isolate the effects of photo-isomerization (jump photo-switching and shot noise), we apply a combination of analytic and computational techniques to analyze the stochastic dynamics of a toy model of this system. Particular attention is paid to applying this model to explore the potential applications of the photo-switchable nanostructure.

  11. Ultrastrong steel via minimal lattice misfit and high-density nanoprecipitation.

    Science.gov (United States)

    Jiang, Suihe; Wang, Hui; Wu, Yuan; Liu, Xiongjun; Chen, Honghong; Yao, Mengji; Gault, Baptiste; Ponge, Dirk; Raabe, Dierk; Hirata, Akihiko; Chen, Mingwei; Wang, Yandong; Lu, Zhaoping

    2017-04-27

    Next-generation high-performance structural materials are required for lightweight design strategies and advanced energy applications. Maraging steels, combining a martensite matrix with nanoprecipitates, are a class of high-strength materials with the potential for matching these demands. Their outstanding strength originates from semi-coherent precipitates, which unavoidably exhibit a heterogeneous distribution that creates large coherency strains, which in turn may promote crack initiation under load. Here we report a counterintuitive strategy for the design of ultrastrong steel alloys by high-density nanoprecipitation with minimal lattice misfit. We found that these highly dispersed, fully coherent precipitates (that is, the crystal lattice of the precipitates is almost the same as that of the surrounding matrix), showing very low lattice misfit with the matrix and high anti-phase boundary energy, strengthen alloys without sacrificing ductility. Such low lattice misfit (0.03 ± 0.04 per cent) decreases the nucleation barrier for precipitation, thus enabling and stabilizing nanoprecipitates with an extremely high number density (more than 10 24 per cubic metre) and small size (about 2.7 ± 0.2 nanometres). The minimized elastic misfit strain around the particles does not contribute much to the dislocation interaction, which is typically needed for strength increase. Instead, our strengthening mechanism exploits the chemical ordering effect that creates backstresses (the forces opposing deformation) when precipitates are cut by dislocations. We create a class of steels, strengthened by Ni(Al,Fe) precipitates, with a strength of up to 2.2 gigapascals and good ductility (about 8.2 per cent). The chemical composition of the precipitates enables a substantial reduction in cost compared to conventional maraging steels owing to the replacement of the essential but high-cost alloying elements cobalt and titanium with inexpensive and lightweight aluminium

  12. The two-qubit quantum Rabi model: inhomogeneous coupling

    International Nuclear Information System (INIS)

    Mao, Lijun; Huai, Sainan; Zhang, Yunbo

    2015-01-01

    We revisit the analytic solution of the two-qubit quantum Rabi model with inhomogeneous coupling and transition frequencies using a displaced oscillator basis. This approach enables us to apply the same truncation rules and techniques adopted in the Rabi model to the two qubits system. The derived analytical spectra match perfectly with the numerical solutions in the parameter regime where the qubits’ transition frequencies are far off-resonance with the field frequency and the interaction strengths reach the ultrastrong coupling regime. We further explore the dynamical behavior of the two qubits as well as the evolution of entanglement. The analytical methods provide unexpectedly accurate results in describing the dynamics of the two qubits in the present experimentally accessible coupling regime. The time evolutions of the probability for the qubits show that the collapse-revival phenomena emerge, survive and finally disappear when one coupling strength increases from weak to strong coupling regimes and the other coupling strength is well into the ultrastrong coupling regime. The inhomogeneous coupling system exhibits new dynamics, which are different from the homogeneous coupling case. (paper)

  13. Switchable and responsive surfaces and materials for biomedical applications

    CERN Document Server

    Zhang, Johnathan

    2015-01-01

    Surface modification of biomaterials can ultimately determine whether a material is accepted or rejected from the human body, and a responsive surface can further make the material ""smart"" and ""intelligent"". Switchable and Responsive Surfaces and Materials for Biomedical Applications outlines synthetic and biological materials that are responsive under different stimuli, their surface design and modification techniques, and applicability in regenerative medicine/tissue engineering,  drug delivery, medical devices, and biomedical diagnostics. Part one provides a detailed overview of swit

  14. Phase Change of Gallium Enables Highly Reversible and Switchable Adhesion.

    Science.gov (United States)

    Ye, Zhou; Lum, Guo Zhan; Song, Sukho; Rich, Steven; Sitti, Metin

    2016-07-01

    Gallium exhibits highly reversible and switchable adhesion when it undergoes a solid-liquid phase transition. The robustness of gallium is notable as it exhibits strong performance on a wide range of smooth and rough surfaces, under both dry and wet conditions. Gallium may therefore find numerous applications in transfer printing, robotics, electronic packaging, and biomedicine. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. High-brightness switchable multiwavelength remote laser in air

    Energy Technology Data Exchange (ETDEWEB)

    Yao Jinping; Cheng Ya; Xu Zhizhan [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Zeng Bin; Li Guihua; Chu Wei; Ni Jielei; Zhang Haisu [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Graduate School of Chinese Academy of Sciences, Beijing 100080 (China); Xu Huailiang [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China); Chin, See Leang [Center for Optics, Universite Laval, Quebec City, Quebec G1V 0A6 (Canada)

    2011-11-15

    We demonstrate a harmonic-seeded switchable multiwavelength laser in air driven by intense midinfrared femtosecond laser pulses, in which population inversion occurs at an ultrafast time scale (i.e., less than {approx}200 fs) owing to direct formation of excited molecular nitrogen ions by strong-field ionization of inner-valence electrons. The bright multiwavelength laser in air opens the perspective for remote detection of multiple pollutants based on nonlinear optical spectroscopy.

  16. Mechanics of responsive polymers via conformationally switchable molecules

    Science.gov (United States)

    Brighenti, Roberto; Artoni, Federico; Vernerey, Franck; Torelli, Martina; Pedrini, Alessandro; Domenichelli, Ilaria; Dalcanale, Enrico

    2018-04-01

    Active materials are those capable of giving some physical reaction under external stimuli coming from the environment such as temperature, pH, light, mechanical stress, etc. Reactive polymeric materials can be obtained through the introduction of switchable molecules in their network, i.e. molecules having two distinct stable conformations: if properly linked to the hosting polymer chains, the switching from one state to the other can promote a mechanical reaction of the material, detectable at the macroscale, and thus enables us to tune the response according to a desired functionality. In the present paper, the main aspects of the mechanical behavior of polymeric materials with embedded switchable molecules-properly linked to the polymer's chains-are presented and discussed. Starting from the micro mechanisms occurring in such active material, a continuum model is developed, providing a straightforward implementation in computational approaches. Finally, some experimental outcomes related to a switchable molecules (known as quinoxaline cavitands) added to an elastomeric PDMS under chemical stimuli, are presented and quantitatively discussed through the use of the developed mechanical framework.

  17. Deformation Behavior of Ultra-Strong and Ductile Mg-Gd-Y-Zn-Zr Alloy with Bimodal Microstructure

    Science.gov (United States)

    Xu, C.; Fan, G. H.; Nakata, T.; Liang, X.; Chi, Y. Q.; Qiao, X. G.; Cao, G. J.; Zhang, T. T.; Huang, M.; Miao, K. S.; Zheng, M. Y.; Kamado, S.; Xie, H. L.

    2018-02-01

    An ultra-strong and ductile Mg-8.2Gd-3.8Y-1Zn-0.4Zr (wt pct) alloy was developed by using hot extrusion to modify the microstructure via forced-air cooling and an artificial aging treatment. A superior strength-ductility balance was obtained that had a tensile yield strength of 466 MPa and an elongation to failure of 14.5 pct. The local strain evolution during the in situ testing of the ultra-strong and ductile alloy was quantitatively analyzed with high-resolution electron backscattered diffraction and digital image correlation. The fracture behavior during the tensile test was characterized by synchrotron X-ray tomography along with SEM and STEM observations. The alloy showed a bimodal microstructure, consisting of dynamically recrystallized (DRXed) grains with random orientations and elongated hot-worked grains with parallel to the extrusion direction. The DRXed grains were deformed by the basal slip and the hot-worked grains were deformed by the prismatic slip dominantly. The strain evolution analysis indicated that the multilayered structure relaxed the strain localization via strain transfer from the DRXed to the hot-worked regions, which led to the high ductility of the alloy. Precipitation of the γ' on basal planes and the β' phases on the prismatic planes of the α-Mg generated closed volumes, which enhanced the strength by pinning dislocations effectively, and contributed to the high ductility by impeding the propagation of micro-cracks inside the grains. The deformation incompatibility between the hot-worked grains and the arched block-shaped long-period stacking ordered (LPSO) phases induced the crack initiation and propagation, which fractured the alloy.

  18. On/off-switchable anti-neoplastic nanoarchitecture

    Science.gov (United States)

    Patra, Hirak K.; Imani, Roghayeh; Jangamreddy, Jaganmohan R.; Pazoki, Meysam; Iglič, Aleš; Turner, Anthony P. F.; Tiwari, Ashutosh

    2015-09-01

    Throughout the world, there are increasing demands for alternate approaches to advanced cancer therapeutics. Numerous potentially chemotherapeutic compounds are developed every year for clinical trial and some of them are considered as potential drug candidates. Nanotechnology-based approaches have accelerated the discovery process, but the key challenge still remains to develop therapeutically viable and physiologically safe materials suitable for cancer therapy. Here, we report a high turnover, on/off-switchable functionally popping reactive oxygen species (ROS) generator using a smart mesoporous titanium dioxide popcorn (TiO2 Pops) nanoarchitecture. The resulting TiO2 Pops, unlike TiO2 nanoparticles (TiO2 NPs), are exceptionally biocompatible with normal cells. Under identical conditions, TiO2 Pops show very high photocatalytic activity compared to TiO2 NPs. Upon on/off-switchable photo activation, the TiO2 Pops can trigger the generation of high-turnover flash ROS and can deliver their potential anticancer effect by enhancing the intracellular ROS level until it crosses the threshold to open the ‘death gate’, thus reducing the survival of cancer cells by at least six times in comparison with TiO2 NPs without affecting the normal cells.

  19. Adhesion of Chlamydomonas microalgae to surfaces is switchable by light

    Science.gov (United States)

    Kreis, Christian Titus; Le Blay, Marine; Linne, Christine; Makowski, Marcin Michal; Bäumchen, Oliver

    2018-01-01

    Microalgae are photoactive microbes that live in liquid-infused environments, such as soil, temporary pools and rocks, where they encounter and colonize a plethora of surfaces. Their photoactivity manifests itself in a variety of processes, including light-directed motility (phototaxis), the growth of microalgal populations, and their photosynthetic machinery. Although microbial responses to light have been widely recognized, any influence of light on cell-surface interactions remains elusive. Here, we reveal that the unspecific adhesion of microalgae to surfaces can be reversibly switched on and off by light. Using a micropipette force spectroscopy technique, we measured in vivo single-cell adhesion forces and show that the microalga's flagella provide light-switchable adhesive contacts with the surface. This light-induced adhesion to surfaces is an active and completely reversible process that occurs on a timescale of seconds. Our results suggest that light-switchable adhesiveness is a natural functionality of microalgae to regulate the transition between the planktonic and the surface-associated state, which yields an adhesive adaptation to optimize the photosynthetic efficiency in conjunction with phototaxis.

  20. Adhesion of Photoactive Microalgae to Surfaces is Switchable by Light

    Science.gov (United States)

    Bäumchen, Oliver; Kreis, Christian; Le Blay, Marine; Linne, Christine; Makowski, Marcin

    The natural habitats of many microorganisms are confined geometries, such as the interstitial space of rocks and soil, where interactions with interfaces and surfaces are of paramount importance. We performed in vivo force spectroscopy experiments on the unicellular biflagellated microalga Chlamydomonas, a prime model organism in cell- and microbiology, and discovered that the flagella-mediated adhesion to surfaces can be switched on and off by light. Time-resolved micropipette experiments show that the light-switchable adhesiveness of the flagella is a completely reversible process that is based on a redistribution of adhesion-promoting flagella-membrane proteins within seconds. Light-switchable adhesion enables the cell to regulate the transition between planktonic and surface-associated state, which possibly represents a significant biological advantage for photoactive microorganisms. In terms of the colonization of surfaces and the formation of biofilms, the findings might have immediate economic and environmental relevance in biotechnological settings, such as photo-bioreactors for the sustainable production of biofuels.

  1. Switchable photosystem-II designer algae for photobiological hydrogen production

    Science.gov (United States)

    Lee, James Weifu

    2010-01-05

    A switchable photosystem-II designer algae for photobiological hydrogen production. The designer transgenic algae includes at least two transgenes for enhanced photobiological H.sub.2 production wherein a first transgene serves as a genetic switch that can controls photosystem II (PSII) oxygen evolution and a second transgene encodes for creation of free proton channels in the algal photosynthetic membrane. In one embodiment, the algae includes a DNA construct having polymerase chain reaction forward primer (302), a inducible promoter (304), a PSII-iRNA sequence (306), a terminator (308), and a PCR reverse primer (310). In other embodiments, the PSII-iRNA sequence (306) is replaced with a CF.sub.1-iRNA sequence (312), a streptomycin-production gene (314), a targeting sequence (316) followed by a proton-channel producing gene (318), or a PSII-producing gene (320). In one embodiment, a photo-bioreactor and gas-product separation and utilization system produce photobiological H.sub.2 from the switchable PSII designer alga.

  2. A Self-Switchable Polymer Reactor for Controlled Catalytic Chemistry Processes with a Hyperbranched Structure

    Directory of Open Access Journals (Sweden)

    Rong Luo

    2018-02-01

    Full Text Available A self-switchable polymer reactor with a hyperbranched structure for controlled catalytic chemistry processes is reported. This polymer reactor was made of silver nanoparticles and a polymer carrier consisting of hyperbranched polyethylenimine and hydroxyethyl acrylate that behaved as thermally switchable domains. Below the transfer temperature, relatively strong catalytic reactivity was demonstrated due to the leading role of hydrophilic groups in the switchable domains, which opened access to the substrate for the packaged silver nanoparticles. In contrast, it showed weak catalysis at relatively high temperatures, reducing from the significantly increased hydrophobicity in the switchable domains. In this way, the polymer reactor displays controllable, tunable, catalytic activity based on this approach. This novel design opens up the opportunity to develop intelligent polymer reactors for controlled catalytic processes.

  3. Self-organization of anisotropic and binary colloids in thermo-switchable 1D microconfinement

    NARCIS (Netherlands)

    De Folter, Julius W J; Liu, Ping; Jiang, Lingxiang; Kuijk, Anke; Bakker, Henriëtte E.; Imhof, Arnout; Van Blaaderen, Alfons; Huang, Jianbin; Kegel, Willem K.; Philipse, Albert P.; Petukhov, Andrei V.

    2015-01-01

    Anisotropic and binary colloids self-assemble into a variety of novel supracolloidal structures within the thermo-switchable confinement of molecular microtubes, achieving structuring at multiple length scales and dimensionalities. The multistage self-assembly strategy involving hard colloidal

  4. Enhanced Switchable Ferroelectric Photovoltaic Effects in Hexagonal Ferrite Thin Films via Strain Engineering.

    Science.gov (United States)

    Han, Hyeon; Kim, Donghoon; Chu, Kanghyun; Park, Jucheol; Nam, Sang Yeol; Heo, Seungyang; Yang, Chan-Ho; Jang, Hyun Myung

    2018-01-17

    Ferroelectric photovoltaics (FPVs) are being extensively investigated by virtue of switchable photovoltaic responses and anomalously high photovoltages of ∼10 4 V. However, FPVs suffer from extremely low photocurrents due to their wide band gaps (E g ). Here, we present a promising FPV based on hexagonal YbFeO 3 (h-YbFO) thin-film heterostructure by exploiting its narrow E g . More importantly, we demonstrate enhanced FPV effects by suitably exploiting the substrate-induced film strain in these h-YbFO-based photovoltaics. A compressive-strained h-YbFO/Pt/MgO heterojunction device shows ∼3 times enhanced photovoltaic efficiency than that of a tensile-strained h-YbFO/Pt/Al 2 O 3 device. We have shown that the enhanced photovoltaic efficiency mainly stems from the enhanced photon absorption over a wide range of the photon energy, coupled with the enhanced polarization under a compressive strain. Density functional theory studies indicate that the compressive strain reduces E g substantially and enhances the strength of d-d transitions. This study will set a new standard for determining substrates toward thin-film photovoltaics and optoelectronic devices.

  5. Monochromatic and electrochemically switchable electrochemiluminescence of perovskite CsPbBr3 nanocrystals.

    Science.gov (United States)

    Huang, Yan; Fang, Mingxiang; Zou, Guizheng; Zhang, Bin; Wang, Huaisheng

    2016-11-10

    Cubic-shaped perovskite CsPbBr 3 nanocrystals (NCs) could be electrochemically injected with holes (or electrons) to produce several charged states under different oxidizing and reducing potentials, and then bring out electrochemiluminescence (ECL) of higher color purity than traditional ECL chemicals and metal chalcogenide NCs, in both annihilation and co-reactant routes. The difference of electrochemical gaps between varied hole and electron injecting potentials displayed little effect on the ECL spectrum and colour purity of CsPbBr 3 NCs. All the excited states generated under different oxidizing and reducing potential couples in ECL of CsPbBr 3 NCs were the same as those in photoluminescence, as all the ECL spectra were almost identical to the CsPbBr 3 NCs' photoluminescence spectrum. Importantly, the ECL of CsPbBr 3 NCs was electrochemically switchable and displayed an obvious "on/off" type feature by changing the sequence of hole injecting and electron injecting processes, as strong ECL could be obtained by injecting holes onto the electron injected NCs, while no or very weak ECL was obtained in the reversed way.

  6. Nanoporous membranes with electrochemically switchable, chemically stabilized ionic selectivity

    Science.gov (United States)

    Small, Leo J.; Wheeler, David R.; Spoerke, Erik D.

    2015-10-01

    Nanopore size, shape, and surface charge all play important roles in regulating ionic transport through nanoporous membranes. The ability to control these parameters in situ provides a means to create ion transport systems tunable in real time. Here, we present a new strategy to address this challenge, utilizing three unique electrochemically switchable chemistries to manipulate the terminal functional group and control the resulting surface charge throughout ensembles of gold plated nanopores in ion-tracked polycarbonate membranes 3 cm2 in area. We demonstrate the diazonium mediated surface functionalization with (1) nitrophenyl chemistry, (2) quinone chemistry, and (3) previously unreported trimethyl lock chemistry. Unlike other works, these chemistries are chemically stabilized, eliminating the need for a continuously applied gate voltage to maintain a given state and retain ionic selectivity. The effect of surface functionalization and nanopore geometry on selective ion transport through these functionalized membranes is characterized in aqueous solutions of sodium chloride at pH = 5.7. The nitrophenyl surface allows for ionic selectivity to be irreversibly switched in situ from cation-selective to anion-selective upon reduction to an aminophenyl surface. The quinone-terminated surface enables reversible changes between no ionic selectivity and a slight cationic selectivity. Alternatively, the trimethyl lock allows ionic selectivity to be reversibly switched by up to a factor of 8, approaching ideal selectivity, as a carboxylic acid group is electrochemically revealed or hidden. By varying the pore shape from cylindrical to conical, it is demonstrated that a controllable directionality can be imparted to the ionic selectivity. Combining control of nanopore geometry with stable, switchable chemistries facilitates superior control of molecular transport across the membrane, enabling tunable ion transport systems.Nanopore size, shape, and surface charge all play

  7. Band-Notched UWB Antenna with Switchable and Tunable Performance

    Directory of Open Access Journals (Sweden)

    Wei Wu

    2016-01-01

    Full Text Available A band-notched UWB antenna is presented, which can switch between two notch bands and tune the central frequency simultaneously. It is the first time that the switchable and tunable behaviours are combined together in band-notched UWB antennas. In the band-notched structure, PIN diodes are used to switch the lower and upper frequency bands, while varactors could vary the central frequency of each notch band continuously. Measurement results show that the notch bands could switch between 4.2 GHz and 5.8 GHz when the state of varactors is fixed, and the ranges of tuning are 4.2–4.8 GHz and 5.8–6.5 GHz when the state of PIN diodes is ON and OFF, respectively.

  8. Chromogenic switchable glazing: Towards the development of the smart window

    Energy Technology Data Exchange (ETDEWEB)

    Lampert, C.M.

    1995-06-01

    The science and technology of chromogenic materials for switchable glazings in building applications is discussed. These glazings can be used for dynamic control of solar and visible energy. Currently many researchers and engineers are involved with the development of products in this field. A summary of activities in Japan, Europe, Australia, USA and Canada is made. The activities of the International Energy Agency are included. Both non-electrically activated and electrically activated glazings are discussed. Technologies covered in the first category are photochromics, and thermochromics and thermotropics. A discussion of electrically activated chromogenic glazings includes dispersed liquid crystals, dispersed particles and electrochromics. A selection of device structures and performance characteristics are compared. A discussion of transparent conductors is presented. Technical issues concerning large-area development of smart windows are discussed.

  9. Electrical Switchability and Dry-Wash Durability of Conductive Textiles.

    Science.gov (United States)

    Wu, Bangting; Zhang, Bowu; Wu, Jingxia; Wang, Ziqiang; Ma, Hongjuan; Yu, Ming; Li, Linfan; Li, Jingye

    2015-06-12

    There is growing interest in the area of conductive textiles in the scientific and industrial community. Herein, we successfully prepared a conductive textile via covalently grafting polyaniline (PANI) onto cotton by a multi-step treatment process. The conductivity of the resultant fabric could be tuned by immersing in water having different pH values. The conductive and insulating properties of the textile could be conveniently switched by alternately immersing in acidic and alkaline bath solutions. Most importantly, the resultant conductive fabrics were able to withstand 40 simulated dry-wash cycles, with almost no decay in the electrical conductivity, indicating their excellent dry-wash durability. The present strategy for fabricating conductive fabrics with excellent switchability of electrical properties and dry-wash durability is expected to provide inspiration for the production of multifunctional conductive textiles for use in hash or sensitive conditions.

  10. Electrical Switchability and Dry-Wash Durability of Conductive Textiles

    Science.gov (United States)

    Wu, Bangting; Zhang, Bowu; Wu, Jingxia; Wang, Ziqiang; Ma, Hongjuan; Yu, Ming; Li, Linfan; Li, Jingye

    2015-06-01

    There is growing interest in the area of conductive textiles in the scientific and industrial community. Herein, we successfully prepared a conductive textile via covalently grafting polyaniline (PANI) onto cotton by a multi-step treatment process. The conductivity of the resultant fabric could be tuned by immersing in water having different pH values. The conductive and insulating properties of the textile could be conveniently switched by alternately immersing in acidic and alkaline bath solutions. Most importantly, the resultant conductive fabrics were able to withstand 40 simulated dry-wash cycles, with almost no decay in the electrical conductivity, indicating their excellent dry-wash durability. The present strategy for fabricating conductive fabrics with excellent switchability of electrical properties and dry-wash durability is expected to provide inspiration for the production of multifunctional conductive textiles for use in hash or sensitive conditions.

  11. Switchable regioselectivity in amine-catalysed asymmetric cycloadditions

    Science.gov (United States)

    Zhou, Zhi; Wang, Zhou-Xiang; Zhou, Yuan-Chun; Xiao, Wei; Ouyang, Qin; Du, Wei; Chen, Ying-Chun

    2017-06-01

    Building small-molecule libraries with structural and stereogenic diversity plays an important role in drug discovery. The development of switchable intermolecular cycloaddition reactions from identical substrates in different regioselective fashions would provide an attractive protocol. However, this also represents a challenge in organic chemistry, because it is difficult to control regioselectivity to afford the products exclusively and at the same time achieve high levels of stereoselectivity. Here, we report the diversified cycloadditions of α‧-alkylidene-2-cyclopentenones catalysed by cinchona-derived primary amines. An asymmetric γ,β‧-regioselective intermolecular [6+2] cycloaddition reaction with 3-olefinic (7-aza)oxindoles is realized through the in situ generation of formal 4-aminofulvenes, while a different β,γ-regioselective [2+2] cycloaddition reaction with maleimides to access fused cyclobutanes is disclosed. In contrast, an intriguing α,γ-regioselective [4+2] cycloaddition reaction is uncovered with the same set of substrates, by employing an unprecedented dual small-molecule catalysis of amines and thiols. All of the cycloaddition reactions exhibit excellent regio- and stereoselectivity, producing a broad spectrum of chiral architectures with high structural diversity and molecular complexity.

  12. Switchable ionic liquids as delignification solvents for lignocellulosic materials.

    Science.gov (United States)

    Anugwom, Ikenna; Eta, Valerie; Virtanen, Pasi; Mäki-Arvela, Päivi; Hedenström, Mattias; Hummel, Michael; Sixta, Herbert; Mikkola, Jyri-Pekka

    2014-04-01

    The transformation of lignocellulosic materials into potentially valuable resources is compromised by their complicated structure. Consequently, new economical and feasible conversion/fractionation techniques that render value-added products are intensely investigated. Herein an unorthodox and feasible fractionation method of birch chips (B. pendula) using a switchable ionic liquid (SIL) derived from an alkanol amine (monoethanol amine, MEA) and an organic super base (1,8-diazabicyclo-[5.4.0]-undec-7-ene, DBU) with two different trigger acid gases (CO2 and SO2 ) is studied. After SIL treatment, the dissolved fractions were selectively separated by a step-wise method using an antisolvent to induce precipitation. The SIL was recycled after concentration and evaporation of anti-solvent. The composition of undissolved wood after MEA-SO2 -SIL treatment resulted in 80 wt % cellulose, 10 wt % hemicelluloses, and 3 wt % lignin, whereas MEA-CO2 -SIL treatment resulted in 66 wt % cellulose, 12 wt % hemicelluloses and 11 wt % lignin. Thus, the MEA-SO2 -SIL proved more efficient than the MEA-CO2 -SIL, and a better solvent for lignin removal. All fractions were analyzed by gas chromatography (GC), Fourier transform infrared spectroscopy (FT-IR), (13) C nuclear magnetic resonance spectroscopy (NMR) and Gel permeation chromatography (GPC). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Switchable Adhesion in Vacuum Using Bio-Inspired Dry Adhesives.

    Science.gov (United States)

    Purtov, Julia; Frensemeier, Mareike; Kroner, Elmar

    2015-11-04

    Suction based attachment systems for pick and place handling of fragile objects like glass plates or optical lenses are energy-consuming and noisy and fail at reduced air pressure, which is essential, e.g., in chemical and physical vapor deposition processes. Recently, an alternative approach toward reversible adhesion of sensitive objects based on bioinspired dry adhesive structures has emerged. There, the switching in adhesion is achieved by a reversible buckling of adhesive pillar structures. In this study, we demonstrate that these adhesives are capable of switching adhesion not only in ambient air conditions but also in vacuum. Our bioinspired patterned adhesive with an area of 1 cm(2) provided an adhesion force of 2.6 N ± 0.2 N in air, which was reduced to 1.9 N ± 0.2 N if measured in vacuum. Detachment was induced by buckling of the structures due to a high compressive preload and occurred, independent of air pressure, at approximately 0.9 N ± 0.1 N. The switch in adhesion was observed at a compressive preload between 5.6 and 6.0 N and was independent of air pressure. The difference between maximum adhesion force and adhesion force after buckling gives a reasonable window of operation for pick and place processes. High reversibility of the switching behavior is shown over 50 cycles in air and in vacuum, making the bioinspired switchable adhesive applicable for handling operations of fragile objects.

  14. Switchable multiwavelength fiber laser using erbium-doped twin-core fiber and nonlinear polarization rotation

    Science.gov (United States)

    Lian, Yudong; Ren, Guobin; Zhu, Bofeng; Gao, Yixiao; Jian, Wei; Ren, Wenhua; Jian, Shuisheng

    2017-05-01

    We propose and demonstrate a switchable multiwavelength fiber laser using erbium-doped twin-core fiber (ED-TCF) and nonlinear polarization rotation (NPR). The number switchability of lasing wavelengths being switched from 1 to 4 and wavelength location switchability could be achieved simultaneously in the proposed configuration with a wavelength spacing of 1.1 nm and an optical signal to noise ratio (OSNR) larger than 43 dB. The output laser powers at different wavelengths are nearly the same with a fluctuation less than 2 dB. The proposed fiber laser shows good stability with wavelength shift within 0.01 nm and peak power fluctuation less than 5 dB. The proposed fiber laser has the advantages of simple structure and stable operation.

  15. Enhanced and switchable spin Hall effect of light near the Brewster angle on reflection

    International Nuclear Information System (INIS)

    Luo Hailu; Zhou Xinxing; Shu Weixing; Wen Shuangchun; Fan Dianyuan

    2011-01-01

    We theorize an enhanced and switchable spin Hall effect (SHE) of light near the Brewster angle on reflection and demonstrate it experimentally. The obtained spin-dependent splitting reaches 3200 nm near the Brewster angle, which is 50 times larger than the previously reported values in refraction. We find that the amplifying factor in weak measurement is not a constant, which is significantly different from that in refraction. As an analogy of SHE in an electronic system, a switchable spin accumulation in SHE of light is detected. We were able to switch the direction of the spin accumulations by slightly adjusting the incident angle.

  16. Optimal control and performance of photovoltachromic switchable glazing for building integration in temperate climates

    International Nuclear Information System (INIS)

    Favoino, Fabio; Fiorito, Francesco; Cannavale, Alessandro; Ranzi, Gianluca; Overend, Mauro

    2016-01-01

    Highlights: • The features and properties of photovoltachromic switchable glazing are presented. • The different possible control strategies for the switchable glazing are presented. • Thermal and daylight performance are co-simulated for rule-based and optimal control. • A novel building performance simulation framework is developed for this aim. • Switchable glazing performance is compared for different controls and climates. - Abstract: The development of adaptive building envelope technologies, and particularly of switchable glazing, can make significant contributions to decarbonisation targets. It is therefore essential to quantify their effect on building energy use and indoor environmental quality when integrated into buildings. The evaluation of their performance presents new challenges when compared to conventional “static” building envelope systems, as they require design and control aspects to be evaluated together, which are also mutually interrelated across thermal and visual physical domains. This paper addresses these challenges by presenting a novel simulation framework for the performance evaluation of responsive building envelope technologies and, particularly, of switchable glazing. This is achieved by integrating a building energy simulation tool and a lighting simulation one, in a control optimisation framework to simulate advanced control of adaptive building envelopes. The performance of a photovoltachromic glazing is evaluated according to building energy use, Useful Daylight Illuminance, glare risk and load profile matching indicators for a sun oriented office building in different temperate climates. The original architecture of photovoltachromic cell provides an automatic control of its transparency as a function of incoming solar irradiance. However, to fully explore the building integration potential of photovoltachromic technology, different control strategies are evaluated, from passive and simple rule based controls, to

  17. Techniques to Improve Ultrasound-Switchable Fluorescence Imaging

    Science.gov (United States)

    Kandukuri, Jayanth

    Novel approaches to the improvement of ultrasound-switchable fluorescence (USF) imaging--a relatively new imaging modality that combines ultrasound and optical imaging techniques--have been proposed for early cancer detection. In USF, a high-intensity focused ultrasound (HIFU) beam is used to induce temperature rise within its acoustic focal region due to which a thermo-sensitive USF contrast agent undergoes a switch in its state by increasing the output of fluorescence photons. By using an increase in fluorescence, one can isolate and quantify the fluorescence properties within the ultrasonic focal area. Therefore, USF is able to provide fluorescence contrast while maintaining ultrasound resolution in tissue. The major challenge of the conventional USF technique is its low axial resolution and its sensitivity (i.e. its signal-to-noise ratio (SNR)). This work focuses on investigating and developing a novel USF system design that can improve the resolution and SNR of USF imaging for biological applications. This work can be divided into two major parts: characterizing the performance of a high-intensity focused ultrasound transducer; and improving the axial resolution and sensitivity of the USF technique. Preliminary investigation was conducted by using an IR camera setup to detect temperature variation and thereby study the performance of the high-intensity focused ultrasound transducer to quantify different parameters of ultrasound-induced temperature focal size (UTFS). Investigations are conducted for the purpose of high-resolution imaging with an emphasis on HIFU-induced thermal focus size, short duration of HIFU-induced temperature increase (to avoid thermal diffusion or conduction), and control of HIFU-induced temperature increase within a few degrees Celsius. Next, the focus was shifted to improving the sensitivity of the ultrasound-switchable fluorescence-imaging technique. In this study, the USF signal is encoded with the modulation frequency of the

  18. Secondary amines as switchable solvents for lipid extraction from non-broken microalgae

    NARCIS (Netherlands)

    Du, Ying; Schuur, Boelo; Samori, C.; Tagliavini, E.; Brilman, Derk Willem Frederik

    2013-01-01

    Lipids from algal biomass may provide renewable fuel and chemical feedstock in large quantities. The energy intensity of drying and milling of algae prior to extraction and of solvent recovery afterwards is a major obstacle. The objective is to use switchable solvents to extract oil directly from

  19. Temperature-Induced Switchable Adhesion using Nickel-Titanium-Polydimethylsiloxane Hybrid Surfaces.

    Science.gov (United States)

    Frensemeier, Mareike; Kaiser, Jessica S; Frick, Carl P; Schneider, Andreas S; Arzt, Eduard; Fertig, Ray S; Kroner, Elmar

    2015-05-01

    A switchable dry adhesive based on a nickel-titanium (NiTi) shape-memory alloy with an adhesive silicone rubber surface has been developed. Although several studies investigate micropatterned, bioinspired adhesive surfaces, very few focus on reversible adhesion. The system here is based on the indentation-induced two-way shape-memory effect in NiTi alloys. NiTi is trained by mechanical deformation through indentation and grinding to elicit a temperature-induced switchable topography with protrusions at high temperature and a flat surface at low temperature. The trained surfaces are coated with either a smooth or a patterned adhesive polydimethylsiloxane (PDMS) layer, resulting in a temperature-induced switchable surface, used for dry adhesion. Adhesion tests show that the temperature-induced topographical change of the NiTi influences the adhesive performance of the hybrid system. For samples with a smooth PDMS layer the transition from flat to structured state reduces adhesion by 56%, and for samples with a micropatterned PDMS layer adhesion is switchable by nearly 100%. Both hybrid systems reveal strong reversibility related to the NiTi martensitic phase transformation, allowing repeated switching between an adhesive and a nonadhesive state. These effects have been discussed in terms of reversible changes in contact area and varying tilt angles of the pillars with respect to the substrate surface.

  20. Elastic recoil detection analysis for the determination of hydrogen concentration profiles in switchable mirrors

    NARCIS (Netherlands)

    Huisman, M.C.; van der Molen, S.J.; Vis, R.D.

    1999-01-01

    Switchable mirrors made of thin films of Y, La or rare-earth (RE) metals exhibit spectacular changes in their optical and electrical properties upon hydrogen loading. The study of these materials has indicated that the occurring phenomena are highly sensitive to the actual hydrogen concentration in

  1. Switchable and tunable microwave frequency multiplication based on a dual-passband microwave photonic filter.

    Science.gov (United States)

    Chen, Hao; Xu, Zuowei; Fu, Hongyan; Zhang, Shiwei; Wu, Congxian; Wu, Hao; Xu, Huiying; Cai, Zhiping

    2015-04-20

    In this paper, a novel approach to implement switchable and tunable microwave frequency multiplication has been proposed and experimentally demonstrated. High order harmonics of microwave signal with external modulation technique can be selected by using a novel switchable dual-passband microwave photonic filter (MPF) based on a modified fiber Mach-Zehnder interferometer (FMZI) and a dispersive medium. By adjusting the polarization controllers in the modified FMZI, the passbands of the MPF can switch between lower frequency, higher frequency or dual-passband states, and by changing the length of the variable optical delay line (VODL) in the modified FMZI, the central frequencies of these passbands can also be tuned. Therefore, tunable and switchable microwave signal frequency multiplication can be achieved. The experimental results show that by modulating a driving signal with frequency of 2.5 GHz, a signal with frequency of 7.5 GHz, which is three times of the driving frequency, the other one with the frequency of 15 GHz, which is six times of the driving frequency can be generated and freely switchable between two frequencies and dual frequency states by simply adjusting the polarization controllers in the modified FMZI.

  2. Superstrate-integrated Switchable Beam Rectangular Microstrip Antenna for Gain Enhancement

    Directory of Open Access Journals (Sweden)

    S. Kawdungta

    2017-06-01

    Full Text Available This research has proposed a switchable beam rectangular microstrip antenna with double parasitic patches, in which two PIN diodes were deployed for manipulation of the main beam direction and a superstrate (i.e. either a dielectric slab or metamaterial for enhancement of the antenna gain. The dielectric slab is a second FR4 substrate while the metamaterial (MTM is the 7×17 periodic structure of planar cycloid dipoles (PCD. Simulations were carried out and three different antenna prototypes (i.e. the proposed switchable beam rectangular microstrip antenna, the proposed antenna either with dielectric slab or MTM fabricated and experimented. The simulation and experimental results are in good agreement and exhibit good impedance matching (|S11| less than 10dB along the operating frequency. The average measured gain is 7 dBi with the unidirectional radiation pattern along the operating frequency. The proposed switchable antennas with and without the superstrate are operable in the 2.4-2.5 GHz WLAN system and switchable in three directions of 0 deg, 30 deg and 330 deg (xy-plane. Moreover, the findings validate the applicability of either the dielectric slab or three MTM block-layers as the superstrate to improve the antenna gain.

  3. STIR: Redox-Switchable Olefin Polymerization Catalysis: Electronically Tunable Ligands for Controlled Polymer Synthesis

    Science.gov (United States)

    2013-03-28

    were reduced using standard hydrogenation conditions with hydrogen and palladium on carbon . Though the synthesis of 1,1’-diaminoferrocene has...forward reduction of diimine 7 proved unusually difficult under typical conditions, although a stepwise procedure utilizing formic acid and sodium...REPORT Final Report: STIR: Redox-Switchable Olefin Polymerization Catalysis: Electronically Tunable Ligands for Controlled Polymer Synthesis 14

  4. Construction of a 4 Zeptoliters Switchable 3D DNA Box Origami

    DEFF Research Database (Denmark)

    Zadegan, Reza Mohammad; Jepsen, Mette DE; Thomsen, Karen E

    2012-01-01

    The DNA origami technique is a recently developed self-assembly method that allows construction of 3D objects at the nanoscale for various applications. In the current study we report the production of a 18 × 18 × 24 nm3 hollow DNA box origami structure with a switchable lid. The structure...

  5. Switchable photovoltaic windows enabled by reversible photothermal complex dissociation from methylammonium lead iodide.

    Science.gov (United States)

    Wheeler, Lance M; Moore, David T; Ihly, Rachelle; Stanton, Noah J; Miller, Elisa M; Tenent, Robert C; Blackburn, Jeffrey L; Neale, Nathan R

    2017-11-23

    Materials with switchable absorption properties have been widely used for smart window applications to reduce energy consumption and enhance occupant comfort in buildings. In this work, we combine the benefits of smart windows with energy conversion by producing a photovoltaic device with a switchable absorber layer that dynamically responds to sunlight. Upon illumination, photothermal heating switches the absorber layer-composed of a metal halide perovskite-methylamine complex-from a transparent state (68% visible transmittance) to an absorbing, photovoltaic colored state (less than 3% visible transmittance) due to dissociation of methylamine. After cooling, the methylamine complex is re-formed, returning the absorber layer to the transparent state in which the device acts as a window to visible light. The thermodynamics of switching and performance of the device are described. This work validates a photovoltaic window technology that circumvents the fundamental tradeoff between efficient solar conversion and high visible light transmittance that limits conventional semitransparent PV window designs.

  6. Fast switchable ferroelectric liquid crystal gratings with two electro-optical modes

    International Nuclear Information System (INIS)

    Ma, Ying; Srivastava, A. K.; Chigrinov, V. G.; Kwok, H.-S.; Wang, Xiaoqian

    2016-01-01

    In this article, we reveal a theoretical and experimental illustration of the Ferroelectric liquid crystal (FLC) grating fabricated by mean of patterned alignment based on photo-alignment. The complexity related to the mismatching of the predefined alignment domains on the top and bottom substrate has been avoided by incorporating only one side photo aligned substrate while the other substrate does not have any alignment layer. Depending on the easy axis in the said alignment domains and the azimuth plane of the impinging polarized light, the diffracting element can be tuned in two modes i.e. DIFF/OFF switchable and DIFF/TRANS switchable modes, which can be applied to different applications. The diffraction profile has been illustrated theoretically that fits well with the experimental finding and thus the proposed diffraction elements with fast response time and high diffraction efficiency could find application in many modern devices.

  7. Biphasic Synergistic Gel Materials with Switchable Mechanics and Self-Healing Capacity.

    Science.gov (United States)

    Zhao, Ziguang; Liu, Yuxia; Zhang, Kangjun; Zhuo, Shuyun; Fang, Ruochen; Zhang, Jianqi; Jiang, Lei; Liu, Mingjie

    2017-10-16

    A fabrication strategy for biphasic gels is reported, which incorporates high-internal-phase emulsions. Closely packed micro-inclusions within the elastic hydrogel matrix greatly improve the mechanical properties of the materials. The materials exhibit excellent switchable mechanics and shape-memory performance because of the switchable micro- inclusions that are incorporated into the hydrogel matrix. The produced materials demonstrated a self-healing capacity that originates from the noncovalent effect of the biphasic heteronetwork. The aforementioned characteristics suggest that the biphasic gels may serve as ideal composite gel materials with validity in a variety of applications, such as soft actuators, flexible devices, and biological materials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Grafted membranes and substrates having surfaces with switchable superoleophilicity and superoleophobicity and applications thereof

    KAUST Repository

    Zhang, Lianbin

    2013-10-10

    Disclosed herein are surface-modified membranes and other surface-modified substrates exhibiting switchable oleophobicity and oleophilicity in aqueous media. These membranes and substrates may be used for variety of applications, including controllable oil/water separation processes, oil spill cleanup, and oil/water purification. Also provided are the making and processing of such surface-modified membranes and other surface-modified substrates.

  9. Switchable photoluminescence of CdTe nanocrystals by temperature-responsive microgels

    Czech Academy of Sciences Publication Activity Database

    Agrawal, M.; Rubio-Retama, J.; Zafeiropoulos, N. E.; Gaponik, N.; Gupta, S.; Cimrová, Věra; Lesnyak, V.; López-Cabarcos, E.; Tzavalas, S.; Rojas-Reyna, R.; Eychmuller, A.; Stamm, M.

    2008-01-01

    Roč. 24, č. 17 (2008), s. 9820-9824 ISSN 0743-7463 R&D Projects: GA AV ČR IAA4050409; GA MŠk(CZ) 1M06031 Institutional research plan: CEZ:AV0Z40500505 Keywords : switchable photoluminescence * temperature-responsive microgels * CdTe nanocrystals Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.097, year: 2008

  10. Electrically switchable holographic liquid crystal/polymer Fresnel lens using a Michelson interferometer.

    Science.gov (United States)

    Jashnsaz, Hossein; Mohajerani, Ezeddin; Nemati, Hossein; Razavi, Seyed Hossein; Alidokht, Isa Ahmad

    2011-06-10

    A holographic technique for fabricating an electrically switchable liquid crystal/polymer composite Fresnel lens is reported. A Michelson interferometer is used to produce the required Fresnel pattern, by placing a convex lens into one path of the interferometer. Simplicity of the method and the possibility of fabricating different focal length lenses in a single arrangement are advantages of the method. The performance of the fabricated lens was demonstrated and its electro-optical properties were investigated for its primary focal length.

  11. 2004 Survey of United States architects on the subject of switchable glazings

    International Nuclear Information System (INIS)

    Sottile, G.M.

    2005-01-01

    The 21st century has ushered in an era marked by the growing integration of technology and other scientific advances into commercial buildings and residential homes. Of particular interest to many architects, developers and builders are 'switchable' glazing, a new category of technologically advanced glass and plastic building materials that can be used to control light, glare and heat entering an office or a home. Interest in switchable glazing technology is influenced by a variety of factors, including a growing movement to offer sustainable, energy-efficient building solutions, and the emerging desire by users to maintain greater control over their working and living environments. This paper examines the movement toward sustainable development and the end-user needs that are driving it. Further, it presents the results of a proprietary survey research study of United States architects on the subject of switchable glazing. This study includes an examination of the attributes most desired by architects regarding smart window technology, and provides additional insight into the potential application of this smart material to the building community

  12. Switchable polarity solvent for liquid phase microextraction of Cd(II) as pyrrolidinedithiocarbamate chelates from environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, Erkan, E-mail: kimyager_erkan@hotmail.com; Soylak, Mustafa, E-mail: soylak@erciyes.edu.tr

    2015-07-30

    A switchable polarity solvent was synthesized from triethylamine (TEA)/water/CO{sub 2} (Dry ice) via proton transfer reaction has been used for the microextraction of cadmium(II) as pyrrolidinedithiocarbamate (APDC) chelate. Cd(II)-APDC chelate was extracted into the switchable polarity solvent drops by adding 2 mL 10 M sodium hydroxide solution. Analytical parameters affecting the complex formation and microextraction efficiency such as pH, amount of ligand, volume of switchable polarity solvent and NaOH, sample volume were optimized. The effects of foreign ions were found tolerably. Under optimum conditions, the detection limit was 0.16 μg L{sup −1} (3Sb/m, n = 7) and the relative standard deviation was 5.4% (n = 7). The method was validated by the analysis of certified reference materials (TMDA-51.3 fortified water, TMDA-53.3 fortified water and SPS-WW2 waste water, 1573a Tomato Leaves and Oriental Basma Tobacco Leaves (INCT-OBTL-5)) and addition/recovery tests. The method was successfully applied to determination of cadmium contents of water, vegetable, fruit and cigarette samples. - Highlights: • Switchable polarity solvent was synthesized from triethylamine (TEA)/water/CO{sub 2}. • The switchable polarity solvent has been used for the microextraction of cadmium(II). • The important factors were optimized. • The method was applied to determination of cadmium in real samples.

  13. Improved performance of Mg–Y alloy thin film switchable mirrors after coating with a superhydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    La, Mao [Department of Chemistry and Environmental Science, Inner Mongolia Normal University, Hohhot, Inner Mongolia, 010020 (China); State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China); Zhou, Huaijuan; Li, Ning; Xin, Yunchuan [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China); Sha, Ren, E-mail: sr@imnu.edu.cn [Department of Chemistry and Environmental Science, Inner Mongolia Normal University, Hohhot, Inner Mongolia, 010020 (China); Bao, Shanhu, E-mail: shanhu.bao@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China); Jin, Ping [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050 (China)

    2017-05-01

    Highlights: • The PTFE films was prepared for use as the top layer of Mg–Y/Pd switchable mirrors. • The PTFE as an antireflection layer to improve the luminous transmission, and also to enhance the switching durability of the switchable mirrors. • The PTFE film has a superhydrophobic surface, which endows the Mg–Y/Pd switchable mirrors with self-cleaning properties. - Abstract: The magnesium based switchable mirrors can reversibly change their optical properties between the transparent and the reflective state as a result of hydrogenation and dehydrogenation. These films can potentially be applied as new energy-saving windows, by controlling the transmittance of solar radiation through the regulation of their reflective state. In this study, magnesium–yttrium (Mg–Y) alloy thin films were prepared using a DC magnetron sputtering method. However, the luminous transmittance in the transparent state and the switching durability of switchable mirrors are too poor to satisfy practical demands. In order to improve the films switching durability, luminous transmittance and the surface functionalization, polytetrafluoroethylene (PTFE) was coated with thermal vacuum deposition for use as the top layer of Mg–Y/Pd switchable mirrors. The PTFE layer had a porous network structure and exhibited a superhydrophobic surface with a water contact angle of approximately 152°. By characterization, PTFE thin films shows the excellent protection role against the oxidization of Mg, the switching durability of the films were improved 3 times, and also shows the antireflection role the luminous transmission of films was enhanced by 7% through the top covered with PTFE.

  14. Switchable reconfiguration of nucleic acid nanostructures by stimuli-responsive DNA machines.

    Science.gov (United States)

    Liu, Xiaoqing; Lu, Chun-Hua; Willner, Itamar

    2014-06-17

    CONSPECTUS: The base sequence in DNA dictates structural and reactivity features of the biopolymer. These properties are implemented to use DNA as a unique material for developing the area of DNA nanotechnology. The design of DNA machines represents a rapidly developing research field in the area of DNA nanotechnology. The present Account discusses the switchable reconfiguration of nucleic acid nanostructures by stimuli-responsive DNA machines, and it highlights potential applications and future perspectives of the area. Programmed switchable DNA machines driven by various fuels and antifuels, such as pH, Hg(2+) ions/cysteine, or nucleic acid strands/antistrands, are described. These include the assembly of DNA tweezers, walkers, a rotor, a pendulum, and more. Using a pH-oscillatory system, the oscillatory mechanical operation of a DNA pendulum is presented. Specifically, the synthesis and "mechanical" properties of interlocked DNA rings are described. This is exemplified with the preparation of interlocked DNA catenanes and a DNA rotaxane. The dynamic fuel-driven reconfiguration of the catenane/rotaxane structures is followed by fluorescence spectroscopy. The use of DNA machines as functional scaffolds to reconfigurate Au nanoparticle assemblies and to switch the fluorescence features within fluorophore/Au nanoparticle conjugates between quenching and surface-enhanced fluorescence states are addressed. Specifically, the fluorescence features of the different DNA machines are characterized as a function of the spatial separation between the fluorophore and Au nanoparticles. The experimental results are supported by theoretical calculations. The future development of reconfigurable stimuli-responsive DNA machines involves fundamental challenges, such as the synthesis of molecular devices exhibiting enhanced complexities, the introduction of new fuels and antifuels, and the integration of new payloads being reconfigured by the molecular devices, such as enzymes or

  15. Conductive Graphitic Carbon Nitride as an Ideal Material for Electrocatalytically Switchable CO2 Capture.

    Science.gov (United States)

    Tan, Xin; Kou, Liangzhi; Tahini, Hassan A; Smith, Sean C

    2015-12-01

    Good electrical conductivity and high electron mobility of the sorbent materials are prerequisite for electrocatalytically switchable CO2 capture. However, no conductive and easily synthetic sorbent materials are available until now. Here, we examined the possibility of conductive graphitic carbon nitride (g-C4N3) nanosheets as sorbent materials for electrocatalytically switchable CO2 capture. Using first-principle calculations, we found that the adsorption energy of CO2 molecules on g-C4N3 nanosheets can be dramatically enhanced by injecting extra electrons into the adsorbent. At saturation CO2 capture coverage, the negatively charged g-C4N3 nanosheets achieve CO2 capture capacities up to 73.9 × 10(13) cm(-2) or 42.3 wt%. In contrast to other CO2 capture approaches, the process of CO2 capture/release occurs spontaneously without any energy barriers once extra electrons are introduced or removed, and these processes can be simply controlled and reversed by switching on/off the charging voltage. In addition, these negatively charged g-C4N3 nanosheets are highly selective for separating CO2 from mixtures with CH4, H2 and/or N2. These predictions may prove to be instrumental in searching for a new class of experimentally feasible high-capacity CO2 capture materials with ideal thermodynamics and reversibility.

  16. Conductive Graphitic Carbon Nitride as an Ideal Material for Electrocatalytically Switchable CO2 Capture

    Science.gov (United States)

    Tan, Xin; Kou, Liangzhi; Tahini, Hassan A.; Smith, Sean C.

    2015-12-01

    Good electrical conductivity and high electron mobility of the sorbent materials are prerequisite for electrocatalytically switchable CO2 capture. However, no conductive and easily synthetic sorbent materials are available until now. Here, we examined the possibility of conductive graphitic carbon nitride (g-C4N3) nanosheets as sorbent materials for electrocatalytically switchable CO2 capture. Using first-principle calculations, we found that the adsorption energy of CO2 molecules on g-C4N3 nanosheets can be dramatically enhanced by injecting extra electrons into the adsorbent. At saturation CO2 capture coverage, the negatively charged g-C4N3 nanosheets achieve CO2 capture capacities up to 73.9 × 1013 cm-2 or 42.3 wt%. In contrast to other CO2 capture approaches, the process of CO2 capture/release occurs spontaneously without any energy barriers once extra electrons are introduced or removed, and these processes can be simply controlled and reversed by switching on/off the charging voltage. In addition, these negatively charged g-C4N3 nanosheets are highly selective for separating CO2 from mixtures with CH4, H2 and/or N2. These predictions may prove to be instrumental in searching for a new class of experimentally feasible high-capacity CO2 capture materials with ideal thermodynamics and reversibility.

  17. Borophene as a Promising Material for Charge-Modulated Switchable CO2 Capture.

    Science.gov (United States)

    Tan, Xin; Tahini, Hassan A; Smith, Sean C

    2017-06-14

    Ideal carbon dioxide (CO 2 ) capture materials for practical applications should bind CO 2 molecules neither too weakly to limit good loading kinetics nor too strongly to limit facile release. Although charge-modulated switchable CO 2 capture has been proposed to be a controllable, highly selective, and reversible CO 2 capture strategy, the development of a practical gas-adsorbent material remains a great challenge. In this study, by means of density functional theory (DFT) calculations, we have examined the possibility of conductive borophene nanosheets as promising sorbent materials for charge-modulated switchable CO 2 capture. Our results reveal that the binding strength of CO 2 molecules on negatively charged borophene can be significantly enhanced by injecting extra electrons into the adsorbent. At saturation CO 2 capture coverage, the negatively charged borophene achieves CO 2 capture capacities up to 6.73 × 10 14 cm -2 . In contrast to the other CO 2 capture methods, the CO 2 capture/release processes on negatively charged borophene are reversible with fast kinetics and can be easily controlled via switching on/off the charges carried by borophene nanosheets. Moreover, these negatively charged borophene nanosheets are highly selective for separating CO 2 from mixtures with CH 4 , H 2 , and/or N 2 . This theoretical exploration will provide helpful guidance for identifying experimentally feasible, controllable, highly selective, and high-capacity CO 2 capture materials with ideal thermodynamics and reversibility.

  18. An Ultrafast Switchable Terahertz Polarization Modulator Based on III-V Semiconductor Nanowires.

    Science.gov (United States)

    Baig, Sarwat A; Boland, Jessica L; Damry, Djamshid A; Tan, H Hoe; Jagadish, Chennupati; Joyce, Hannah J; Johnston, Michael B

    2017-04-12

    Progress in the terahertz (THz) region of the electromagnetic spectrum is undergoing major advances, with advanced THz sources and detectors being developed at a rapid pace. Yet, ultrafast THz communication is still to be realized, owing to the lack of practical and effective THz modulators. Here, we present a novel ultrafast active THz polarization modulator based on GaAs semiconductor nanowires arranged in a wire-grid configuration. We utilize an optical pump-terahertz probe spectroscopy system and vary the polarization of the optical pump beam to demonstrate ultrafast THz modulation with a switching time of less than 5 ps and a modulation depth of -8 dB. We achieve an extinction of over 13% and a dynamic range of -9 dB, comparable to microsecond-switchable graphene- and metamaterial-based THz modulators, and surpassing the performance of optically switchable carbon nanotube THz polarizers. We show a broad bandwidth for THz modulation between 0.1 and 4 THz. Thus, this work presents the first THz modulator which combines not only a large modulation depth but also a broad bandwidth and picosecond time resolution for THz intensity and phase modulation, making it an ideal candidate for ultrafast THz communication.

  19. Smart surfaces with switchable superoleophilicity and superoleophobicity in aqueous media: Toward controllable oil/water separation

    KAUST Repository

    Zhang, L.

    2012-02-01

    Advanced materials with surfaces that have controllable oil wettability when submerged in aqueous media have great potential for various underwater applications. Here we have developed smart surfaces on commonly used materials, including non-woven textiles and polyurethane sponges, which are able to switch between superoleophilicity and superoleophobicity in aqueous media. The smart surfaces are obtained by grafting a block copolymer, comprising blocks of pH-responsive poly(2-vinylpyridine) and oleophilic/hydrophobic polydimethylsiloxane (i.e., P2VP-b-PDMS) on these materials. The P2VP block can alter its wettability and its conformation via protonation and deprotonation in response to the pH of the aqueous media, which provides controllable and switchable access of oil by the PDMS block, resulting in the switchable surface oil wettability in the aqueous media. On the other hand, the high flexibility of the PDMS block facilitates the reversible switching of the surface oil wettability. As a proof of concept, we also demonstrate that materials functionalized with our smart surfaces can be used for highly controllable oil/water separation processes.

  20. A Switchable Linker-Based Immunoassay for Ultrasensitive Visible Detection of Salmonella in Tomatoes.

    Science.gov (United States)

    Hahn, Jungwoo; Kim, Eunghee; You, Young Sang; Gunasekaran, Sundaram; Lim, Seokwon; Choi, Young Jin

    2017-10-01

    On-site detection for sensitive identification of foodborne pathogens on fresh produce with minimal use of specialized instrumentation is crucial to the food industry. A switchable linker (SL)-based immunoassay was designed for ultrasensitive on-site detection of Salmonella in tomato samples. The assay is based on large-scale aggregation of gold nanoparticles (GNPs), induced by a quantitative relationship among the biotinylated Salmonella polyclonal antibody (b-Ab) used as the SL, the functionalized GNPs, and Salmonella. Important factors such as the concentration of SLs, time required for large-scale aggregation, and selectivity of b-Ab were optimized to minimize the detection time (within 45 min with gentle agitation) and achieve the lowest limit of detection (LOD; 10 CFU/g in tomato samples) possible. This SL-based immunoassay with its relatively low LOD and short detection time may meet the need for rapid, simple, on-site analysis of pathogens in fresh produce. The novel switchable linker-based immunoassay is a rapid, specific, and sensitive method that has potential applications for routine diagnostics of Salmonella in tomato products. These advantages make it a practical approach for general use in the processing industry to detect Salmonella rapidly and to implement appropriate regulatory procedures. Furthermore, it could be applied to other fresh products including cantaloupe, strawberry, and cucumbers. © 2017 Institute of Food Technologists®.

  1. Conductive Graphitic Carbon Nitride as an Ideal Material for Electrocatalytically Switchable CO2 Capture

    Science.gov (United States)

    Tan, Xin; Kou, Liangzhi; Tahini, Hassan A.; Smith, Sean C.

    2015-01-01

    Good electrical conductivity and high electron mobility of the sorbent materials are prerequisite for electrocatalytically switchable CO2 capture. However, no conductive and easily synthetic sorbent materials are available until now. Here, we examined the possibility of conductive graphitic carbon nitride (g-C4N3) nanosheets as sorbent materials for electrocatalytically switchable CO2 capture. Using first-principle calculations, we found that the adsorption energy of CO2 molecules on g-C4N3 nanosheets can be dramatically enhanced by injecting extra electrons into the adsorbent. At saturation CO2 capture coverage, the negatively charged g-C4N3 nanosheets achieve CO2 capture capacities up to 73.9 × 1013 cm−2 or 42.3 wt%. In contrast to other CO2 capture approaches, the process of CO2 capture/release occurs spontaneously without any energy barriers once extra electrons are introduced or removed, and these processes can be simply controlled and reversed by switching on/off the charging voltage. In addition, these negatively charged g-C4N3 nanosheets are highly selective for separating CO2 from mixtures with CH4, H2 and/or N2. These predictions may prove to be instrumental in searching for a new class of experimentally feasible high-capacity CO2 capture materials with ideal thermodynamics and reversibility. PMID:26621618

  2. Raman scattering with strongly coupled vibron-polaritons

    Science.gov (United States)

    Strashko, Artem; Keeling, Jonathan

    2016-08-01

    Strong coupling between cavity photons and molecular vibrations can lead to the formation of vibron-polaritons. In a recent experiment with PVAc molecules in a metal-metal microcavity [Shalabney et al., Angew. Chem., Int. Ed. 54, 7971 (2015), 10.1002/anie.201502979], such a coupling was observed to enhance the Raman scattering probability by several orders of magnitude. Inspired by this, we theoretically analyze the effect of strong photon-vibron coupling on the Raman scattering amplitude of organic molecules. This problem has recently been addressed by del Pino, Feist, and Garcia-Vidal [J. Phys. Chem. C 119, 29132 (2015), 10.1021/acs.jpcc.5b11654] using exact numerics for a small number of molecules. In this paper we derive compact analytic results for any number of molecules, also including the ultrastrong-coupling regime. Our calculations predict a division of the Raman signal into upper and lower polariton modes, with some enhancement to the lower polariton Raman amplitude due to the mode softening under strong coupling.

  3. Development and characterization of amorphous acrylate networks for use as switchable adhesives inspired from shapememory behavior

    Science.gov (United States)

    Lakhera, Nishant

    Several types of insects and animals such as spiders and geckos are inherently able to climb along vertical walls and ceilings. This remarkable switchable adhesive behavior has been attributed to the fibrillar structures on their feet, with size ranging from few nanometers to a few micrometers depending on the species. Several studies have attempted to create synthetic micro-patterned surfaces trying to imitate this adhesive behavior seen in nature. The experimental procedures are scattered, with sole purpose of trying to increase adhesion, thereby making direct comparison between studies very difficult. There is a lack of fundamental understanding on adhesion of patterned surfaces. The influence of critical parameters like material modulus, glass transition temperature, viscoelastic effects, temperature and water absorption on adhesion is not fully explored and characterized. These parameters are expected to have a decisive influence on adhesion behavior of the polymer. Previous studies have utilized conventional "off-the-shelf" materials like epoxy, polyurethanes etc. It is however, impossible to change the material modulus, glass transition temperature etc. of these polymer systems without changing the base constituents itself, thereby explaining the gaps in the current research landscape. The purpose of this study was to use acrylate shape-memory polymers (SMPs) for their ability to be tailored to specific mechanical properties by control of polymer chemistry, without changing the base constituents. Polymer networks with tailorable glass transition, material modulus, water absorption etc. were developed and adhesion studies were performed to investigate the influence of temperature, viscoelastic effects, material modulus on the adhesion behavior of flat acrylate polymer surfaces. The knowledge base gained from these studies was utilized to better understand the fundamental mechanisms associated with adhesion behavior of patterned acrylate surfaces. Thermally

  4. Wavelength-switchable multiwavelength erbium-doped fiber laser based on a D-shaped fiber with a photoresist thin-film overlay

    Energy Technology Data Exchange (ETDEWEB)

    Han, Young-Geun [Hanyang University, Seoul (Korea, Republic of)

    2011-04-15

    A wavelength-switchable multiwavelength erbium-doped fiber (EDF) laser based on a D-shaped fiber with a photoresist (PR) thin-film overlay is proposed and experimentally demonstrated. The D-shaped fiber with a PR thin-film overlay is implemented as a multichannel filter. Based on the evanescent field coupling between the D-shaped fiber and the PR thin-film overlay, periodic transmission characteristics are obtained. The wavelength spacing of the D-shaped fiber with the PR thin-film overlay is controlled by changing the thickness and the refractive index of the PR thin film overlay. By inserting the proposed multichannel filter into an EDF ring laser, a multiwavelength EDF laser is achieved. The homogenous line broadening of erbium ions for the realization of stable operation of the multiwavelength EDF ring laser is suppressed by using a nonlinear polarization rotation. A high-quality multiwavelength output with a high extinction ratio of {approx}0 dB is realized. The output fluctuation of the proposed multiwavelength EDF ring laser is measured to be less than 0.3 dB. Since the transmission characteristics of the proposed multichannel filter are controlled by using two orthogonal input polarization states, multiwavelength lasing outputs are switched.

  5. Leaf venation, as a resistor, to optimize a switchable IR absorber.

    Science.gov (United States)

    Alston, M E; Barber, R

    2016-08-24

    Leaf vascular patterns are the mechanisms and mechanical support for the transportation of fluidics for photosynthesis and leaf development properties. Vascular hierarchical networks in leaves have far-reaching functions in optimal transport efficiency of functional fluidics. Embedding leaf morphogenesis as a resistor network is significant in the optimization of a translucent thermally functional material. This will enable regulation through pressure equalization by diminishing flow pressure variation. This paper investigates nature's vasculature networks that exhibit hierarchical branching scaling applied to microfluidics. To enable optimum potential for pressure drop regulation by algorithm design. This code analysis of circuit conduit optimization for transport fluidic flow resistance is validated against CFD simulation, within a closed loop network. The paper will propose this self-optimization, characterization by resistance seeking targeting to determine a microfluidic network as a resistor. To advance a thermally function material as a switchable IR absorber.

  6. Rational Design of a Green-Light-Mediated Unimolecular Platform for Fast Switchable Acidic Sensing.

    Science.gov (United States)

    Zhou, Yunyun; Zou, Qi; Qiu, Jing; Wang, Linjun; Zhu, Liangliang

    2018-02-01

    A controllable sensing ability strongly connects to complex and precise events in diagnosis and treatment. However, imposing visible light into the molecular-scale mediation of sensing processes is restricted by the lack of structural relevance. To address this critical challenge, we present the rational design, synthesis, and in vitro studies of a novel cyanostyryl-modified azulene system for green-light-mediated fast switchable acidic sensing. The advantageous features of the design include a highly efficient green-light-driven Z/E-isomerization (a quantum yield up to 61.3%) for fast erasing chromatic and luminescent expressions and a superior compatibility with control of ratiometric protonation. Significantly, these merits of the design enable the development of a microfluidic system to perform a green-light-mediated reusable sensing function toward a gastric acid analyte in a miniaturized platform. The results may provide new insights for building future integrated green materials.

  7. Switchable self-assembly of Prussian blue analogs nano-tiles triggered by salt stimulus.

    Science.gov (United States)

    Dedovets, D; Bauduin, P; Causse, J; Girard, L; Diat, O

    2016-01-28

    Prussian blue analogs (PBAs) are materials well known for their bulk physical and (electro)-chemical properties, with an outstanding selectivity for caesium in ion exchange processes. Crystalline nano-tiles, made of copper based PBA, are produced and dispersed in water by tuning their electrostatic interactions. The shape and size of the nano-crystals are determined by combining scattering, microscopic and spectral techniques. We show here that Cu-PBA nano-tiles form planar superstructures by an edge to edge self-assembly process controlled by specific cation effect and ionic strength. Sedimentation and (re-)dispersion of the nano-tiles are found to be fully reversible. This switchable anisotropic self-assembly triggered by salt stimulus makes PBA nanocrystals potentially interesting for applications.

  8. Hybrid semiconductor-dielectric metamaterial modulation for switchable bi-directional THz absorbers

    Science.gov (United States)

    Le, Ly Nguyen; Thang, Nguyen Manh; Thuy, Le Minh; Tung, Nguyen Thanh

    2017-01-01

    There is an increasing interest for electromagnetic metamaterials that show mutable absorption properties with real-time and dynamic control. In this paper, we investigate a modulation of bi-directional metamaterial absorbers that is thermally switchable at terahertz frequencies. The metamaterial absorber is composed of symmetric hybrid semiconductor-dielectric cut-wire-pair structures, whose electromagnetic responses can be actively manipulated by utilizing an external heat source. As increasing the temperature of metamaterials from 300 to 350 K, we demonstrate that the magnetic resonance can be systematically blue-shifted and overlapped with the electric resonance, which is unaffectedly settled at about 0.8 THz. This superposition provides an effective mechanism to control the absorption intensity from 43% to nearly 95%. Finite integration simulation technique, standard retrieval method, and equivalent circuit model are employed to elaborate our idea.

  9. Achieving dynamic switchable filter based on a transmutable metasurface using SMA

    Science.gov (United States)

    Chen, Xin; Gao, Jinsong; Kang, Bonan

    2017-09-01

    We propose a switchable filter composed of transmutable array using shape memory alloys (SMA). It could exhibit a temperature induced morphology change spontaneously like the biological excitability, acting as a shutter that allows the incident energy to be selectively transmitted or reflected with in excess of 12dB isolation at the certain frequencies for both polarizations. Equivalent circuit models describe the operational principle qualitatively and the switching effect is underpinned by the full-wave analysis. A further physical mechanism is shown by contrasting the distributions of electric field and surface current on the surface at the same frequency for the two working modes. The experimental results consist with the theoretical simulations, indicating that the metasurface could serve as one innovative solution for manipulating the electromagnetic waves and enlighten the next generation of advanced electromagnetic materials with more freedom in the processes of design and manufacturing.

  10. Achieving dynamic switchable filter based on a transmutable metasurface using SMA

    Directory of Open Access Journals (Sweden)

    Xin Chen

    2017-09-01

    Full Text Available We propose a switchable filter composed of transmutable array using shape memory alloys (SMA. It could exhibit a temperature induced morphology change spontaneously like the biological excitability, acting as a shutter that allows the incident energy to be selectively transmitted or reflected with in excess of 12dB isolation at the certain frequencies for both polarizations. Equivalent circuit models describe the operational principle qualitatively and the switching effect is underpinned by the full-wave analysis. A further physical mechanism is shown by contrasting the distributions of electric field and surface current on the surface at the same frequency for the two working modes. The experimental results consist with the theoretical simulations, indicating that the metasurface could serve as one innovative solution for manipulating the electromagnetic waves and enlighten the next generation of advanced electromagnetic materials with more freedom in the processes of design and manufacturing.

  11. Switchable diode effect in oxygen vacancy-modulated SrTiO{sub 3} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Xinqiang; Shuai, Yao; Wu, Chuangui; Luo, Wenbo; Sun, Xiangyu; Zeng, Huizhong; Bai, Xiaoyuan; Gong, Chaoguan; Jian, Ke; Zhang, Wanli [University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices, Chengdu (China); Zhang, Lu; Guo, Hongliang [University of Electronic Science and Technology of China, The Center for Robotics, Chengdu (China); Tian, Benlang [26th Institute of China Electronics Technology Group Corporation, Chongqing (China)

    2017-09-15

    SrTiO{sub 3} (STO) single crystal wafer was annealed in vacuum, and co-planar metal-insulator-metal structure of Pt/Ti/STO/Ti/Pt were formed by sputtering Pt/Ti electrodes onto the surface of STO after annealing. The forming-free resistive switching behavior with self-compliance property was observed in the sample. The sample showed switchable diode effect, which is explained by a simple model that redistribution of oxygen vacancies (OVs) under the external electric field results in the formation of n-n{sup +} junction or n{sup +}-n junction (n donated n-type semiconductor; n{sup +} donated heavily doped n-type semiconductor). The self-compliance property is also interpreted by the formation of n-n{sup +}/n{sup +}-n junction caused by the migration of the OVs under the electric field. (orig.)

  12. Surface induces different crystal structures in a room temperature switchable spin crossover compound.

    Science.gov (United States)

    Gentili, Denis; Liscio, Fabiola; Demitri, Nicola; Schäfer, Bernhard; Borgatti, Francesco; Torelli, Piero; Gobaut, Benoit; Panaccione, Giancarlo; Rossi, Giorgio; Degli Esposti, Alessandra; Gazzano, Massimo; Milita, Silvia; Bergenti, Ilaria; Ruani, Giampiero; Šalitroš, Ivan; Ruben, Mario; Cavallini, Massimiliano

    2016-01-07

    We investigated the influence of surfaces in the formation of different crystal structures of a spin crossover compound, namely [Fe(L)2] (LH: (2-(pyrazol-1-yl)-6-(1H-tetrazol-5-yl)pyridine), which is a neutral compound thermally switchable around room temperature. We observed that the surface induces the formation of two different crystal structures, which exhibit opposite spin transitions, i.e. on heating them up to the transition temperature, one polymorph switches from high spin to low spin and the second polymorph switches irreversibly from low spin to high spin. We attributed this inversion to the presence of water molecules H-bonded to the complex tetrazolyl moieties in the crystals. Thin deposits were investigated by means of polarized optical microscopy, atomic force microscopy, X-ray diffraction, X-ray absorption spectroscopy and micro Raman spectroscopy; moreover the analysis of the Raman spectra and the interpretation of spin inversion were supported by DFT calculations.

  13. Reverse engineering of an affinity-switchable molecular interaction characterized by atomic force microscopy single-molecule force spectroscopy.

    Science.gov (United States)

    Anselmetti, Dario; Bartels, Frank Wilco; Becker, Anke; Decker, Björn; Eckel, Rainer; McIntosh, Matthew; Mattay, Jochen; Plattner, Patrik; Ros, Robert; Schäfer, Christian; Sewald, Norbert

    2008-02-19

    Tunable and switchable interaction between molecules is a key for regulation and control of cellular processes. The translation of the underlying physicochemical principles to synthetic and switchable functional entities and molecules that can mimic the corresponding molecular functions is called reverse molecular engineering. We quantitatively investigated autoinducer-regulated DNA-protein interaction in bacterial gene regulation processes with single atomic force microscopy (AFM) molecule force spectroscopy in vitro, and developed an artificial bistable molecular host-guest system that can be controlled and regulated by external signals (UV light exposure and thermal energy). The intermolecular binding functionality (affinity) and its reproducible and reversible switching has been proven by AFM force spectroscopy at the single-molecule level. This affinity-tunable optomechanical switch will allow novel applications with respect to molecular manipulation, nanoscale rewritable molecular memories, and/or artificial ion channels, which will serve for the controlled transport and release of ions and neutral compounds in the future.

  14. Switchable microwave photonic filter between high Q bandpass filter and notch filter with flat passband based on phase modulation.

    Science.gov (United States)

    Yu, Yuan; Xu, Enming; Dong, Jianji; Zhou, Lina; Li, Xiang; Zhang, Xinliang

    2010-11-22

    We propose and demonstrate a novel switchable microwave photonic filter based on phase modulation. Both a microwave high Q bandpass filter and a microwave notch filter with flat passband are achieved respectively. And the switchability between them by tuning the two tunable optical bandpass filters is demonstrated. We also present a theoretical model and analytical expression for the proposed scheme. A frequency response of a high Q bandpass filter with a Q factor of 327 and a rejection ratio of exceeding 42 dB, and a frequency response of a notch filter with flat passband with a rejection ratio exceeding 34 dB are experimentally obtained. The operation frequency of microwave photonic filter is around 20 GHz.

  15. Wavelength switchable flat-top all-fiber comb filter based on a double-loop Mach-Zehnder interferometer.

    Science.gov (United States)

    Luo, Ai-Ping; Luo, Zhi-Chao; Xu, Wen-Cheng; Cui, Hu

    2010-03-15

    A wavelength switchable all-fiber comb filter with flat-top spectral response based on a double-loop Mach-Zehnder (M-Z) interferometer is proposed and demonstrated. The proposed flat-top filter consists of a rotatable polarizer and a double-loop M-Z interferometer composed of two fiber couplers with a polarization controller (PC) in the first loop. In the theoretical analysis, when the second coupler of the M-Z interferometer is a non-3dB one, with proper settings of the polarization state of the input light and the PC, the wavelength switchable comb filter with flat-top passband can be obtained. Theoretical prediction was verified by experimental demonstration. The measured 1 dB bandwidth was 0.51 nm with a channel spacing of 0.98 nm, indicating that the flat-top passband of 1 dB bandwidth extends to about 50% of the comb spacing.

  16. Electronic devices containing switchably conductive silicon oxides as a switching element and methods for production and use thereof

    Science.gov (United States)

    Tour, James M; Yao, Jun; Natelson, Douglas; Zhong, Lin; He, Tao

    2013-11-26

    In various embodiments, electronic devices containing switchably conductive silicon oxide as a switching element are described herein. The electronic devices are two-terminal devices containing a first electrical contact and a second electrical contact in which at least one of the first electrical contact or the second electrical contact is deposed on a substrate to define a gap region therebetween. A switching layer containing a switchably conductive silicon oxide resides in the the gap region between the first electical contact and the second electrical contact. The electronic devices exhibit hysteretic current versus voltage properties, enabling their use in switching and memory applications. Methods for configuring, operating and constructing the electronic devices are also presented herein.

  17. Switchable Diastereoselectivity in the Fluoride Promoted Vinylogous Mukaiyama-Michael Reaction of 2-Trimethylsilyloxyfuran Catalyzed by Crown Ethers

    KAUST Repository

    Della Sala, Giorgio

    2017-05-31

    The fluoride promoted vinylogous Mukaiyama-Michael reaction (VMMR) of 2-trimethylsilyloxyfuran with diverse α,β-unsaturated ketones is described. The TBAF catalyzed VMMR afforded high anti-diastereoselectivity irrespective of the solvents used. The KF/crown ethers catalytic systems proved to be highly efficient in terms of yields and resulted in a highly diastereoselective unprecedented solvent/catalyst switchable reaction. Anti-adducts were obtained as single diastereomers or with excellent diastereoselectivities when benzo-15-crown-5 in CH2Cl2 was employed. On the other hand, high syn-diastereoselectivities (from 76:24 to 96:4) were achieved by employing dicyclohexane-18-crown-6 in toluene. Based on DFT calculations, the catalysts/solvents-dependent switchable diastereoselectivities are proposed to be the result of loose or tight cation-dienolate ion pairs.

  18. Tunable and switchable multi-wavelength erbium-doped fiber laser with highly nonlinear photonic crystal fiber and polarization controllers

    International Nuclear Information System (INIS)

    Liu, X M; Lin, A; Zhao, W; Lu, K Q; Wang, Y S; Zhang, T Y; Chung, Y

    2008-01-01

    We have proposed a novel multi-wavelength erbium-doped fiber laser by using two polarization controllers and a sampled chirped fiber Bragg grating(SC-FBG). On the assistance of SC-FBG, the proposed fiber lasers with excellent stability and uniformity are tunable and switchable by adjusting the polarization controllers. Our laser can stably lase two waves and up to eight waves simultaneously at room temperature

  19. Improved performance of Mg-Y alloy thin film switchable mirrors after coating with a superhydrophobic surface

    Science.gov (United States)

    La, Mao; Zhou, Huaijuan; Li, Ning; Xin, Yunchuan; Sha, Ren; Bao, Shanhu; Jin, Ping

    2017-05-01

    The magnesium based switchable mirrors can reversibly change their optical properties between the transparent and the reflective state as a result of hydrogenation and dehydrogenation. These films can potentially be applied as new energy-saving windows, by controlling the transmittance of solar radiation through the regulation of their reflective state. In this study, magnesium-yttrium (Mg-Y) alloy thin films were prepared using a DC magnetron sputtering method. However, the luminous transmittance in the transparent state and the switching durability of switchable mirrors are too poor to satisfy practical demands. In order to improve the films switching durability, luminous transmittance and the surface functionalization, polytetrafluoroethylene (PTFE) was coated with thermal vacuum deposition for use as the top layer of Mg-Y/Pd switchable mirrors. The PTFE layer had a porous network structure and exhibited a superhydrophobic surface with a water contact angle of approximately 152°. By characterization, PTFE thin films shows the excellent protection role against the oxidization of Mg, the switching durability of the films were improved 3 times, and also shows the antireflection role the luminous transmission of films was enhanced by 7% through the top covered with PTFE.

  20. Blue Light Switchable Bacterial Adhesion as a Key Step toward the Design of Biofilms.

    Science.gov (United States)

    Chen, Fei; Wegner, Seraphine V

    2017-12-15

    The control of where and when bacteria adhere to a substrate is a key step toward controlling the formation and organization in biofilms. This study shows how we engineer bacteria to adhere specifically to substrates with high spatial and temporal control under blue light, but not in the dark, by using photoswitchable interaction between nMag and pMag proteins. For this, we express pMag proteins on the surface of E. coli so that the bacteria can adhere to substrates with immobilized nMag protein under blue light. These adhesions are reversible in the dark and can be repeatedly turned on and off. Further, the number of bacteria that can adhere to the substrate as well as the attachment and detachment dynamics are adjustable by using different point mutants of pMag and altering light intensity. Overall, the blue light switchable bacteria adhesions offer reversible, tunable and bioorthogonal control with exceptional spatial and temporal resolution. This enables us to pattern bacteria on substrates with great flexibility.

  1. Charge-controlled switchable CO adsorption on FeN4 cluster embedded in graphene

    Science.gov (United States)

    Omidvar, Akbar

    2018-02-01

    Electrical charging of an FeN4 cluster embedded in graphene (FeN4G) is proposed as an approach for electrocatalytically switchable carbon monoxide (CO) adsorption. Using density functional theory (DFT), we found that the CO molecule is strongly adsorbed on the uncharged FeN4G cluster. Our results show that the adsorption energy of a CO molecule on the FeN4G cluster is dramatically decreased by introducing extra electrons into the cluster. Once the charges are removed, the CO molecule is spontaneously adsorbed on the FeN4G absorbent. In the framework of frontier molecular orbital (FMO) analysis, the enhanced sensitivity and reactivity of the FeN4G cluster towards the CO molecule can be interpreted in terms of interaction between the HOMO of CO molecule and the LUMO of FeN4G cluster. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Our study indicates that the FeN4G nanomaterial is an excellent absorbent for controllable and reversible capture and release of the CO.

  2. A Planar UWB Antenna with Switchable Single/Double Band-Rejection Characteristics

    Directory of Open Access Journals (Sweden)

    V. Sharbati

    2016-09-01

    Full Text Available In this Paper, a reconfigurable antenna with capability to operate in the ultrawideband (UWB mode from 2.85 to 14.4 GHz with switchable notch bands of 3.25–4.26 GHz, 5.1–5.9 GHz or 7.1-7.8 GHz, is presented. The proposed antenna has a simple configuration and compact size of 17 × 14 mm2. To make the band-notches, three methods (methods of slot antenna, parasitic patches and backplane structure are used. To achieve the reconfigurability, three PIN diode are placed on the proposed antenna. A PIN diode is inserted over the L-shaped parasitic element and the rectangular patch, another one is placed between the two parasitic elements on the ground plane, and other across the square ring-shaped slot, respectively. Antenna performance can be changed by adjusting the status of the PIN diodes that make the band-notches in applications bands (WLAN, WiMAX/C-band and X-band. Good group delay and monopole-like radiation pattern characteristics are achieved in the frequency band of interest. The antenna performance both by simulation and by experiment indicates that it is suitable and a good candidate for UWB applications.

  3. Switchable Induced Polarization in LaAlO3/SrTiO3 Heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Bark, C [University of Wisconsin, Madison; Sharma, P. [University of Nebraska; Wang, Y. [University of Nebraska; Baek, Seung Hyub [University of Wisconsin, Madison; Lee, S. [University of Wisconsin, Madison; Ryu, S. [University of Wisconsin, Madison; Folkman, C H [University of Wisconsin; Paudel, Tula R [ORNL; Kumar, Amit [ORNL; Kalinin, Sergei V [ORNL; Sokolov, A. [University of Nebraska; Tsymbal, E Y [University of Nebraska, Lincoln; Rzchowski, M [University of Wisconsin; Gruverman, Alexei [ORNL; Eom, Professor Chang-Beom [University of Wisconsin, Madison

    2012-01-01

    Demonstration of a tunable conductivity of the LaAlO3/SrTiO3 interfaces drew significant attention to the development of oxide electronic structures where electronic confinement can be reduced to the nanometer range. While the mechanisms for the conductivity modulation are quite different and include metal insulator phase transition and surface charge writing, generally it is implied that this effect is a result of electrical modification of the LaAlO3 surface (either due to electrochemical dissociation of surface adsorbates or free charge deposition) leading to the change in the twodimensional electron gas (2DEG) density at the LaAlO3/SrTiO3 (LAO/STO) interface. In this paper, using piezoresponse force microscopy we demonstrate a switchable electromechanical response of the LAO overlayer, which we attribute to the motion of oxygen vacancies through the LAO layer thickness. These electrically induced reversible changes in bulk stoichiometry of the LAO layer are a signature of a possible additional mechanism for nanoscale oxide 2DEG control on LAO/STO interfaces.

  4. Durability of switchable QR code carriers under hydrolytic and photolytic conditions

    Science.gov (United States)

    Ecker, Melanie; Pretsch, Thorsten

    2013-09-01

    Following a guest diffusion approach, the surface of a shape memory poly(ester urethane) (PEU) was either black or blue colored. Bowtie-shaped quick response (QR) code carriers were then obtained from laser engraving and cutting, before thermo-mechanical functionalization (programming) was applied to stabilize the PEU in a thermo-responsive (switchable) state. The stability of the dye within the polymer surface and long-term functionality of the polymer were investigated against UVA and hydrolytic ageing. Spectrophotometric investigations verified UVA ageing-related color shifts from black to yellow-brownish and blue to petrol-greenish whereas hydrolytically aged samples changed from black to greenish and blue to light blue. In the case of UVA ageing, color changes were accompanied by dye decolorization, whereas hydrolytic ageing led to contrast declines due to dye diffusion. The Michelson contrast could be identified as an effective tool to follow ageing-related contrast changes between surface-dyed and laser-ablated (undyed) polymer regions. As soon as the Michelson contrast fell below a crucial value of 0.1 due to ageing, the QR code was no longer decipherable with a scanning device. Remarkably, the PEU information carrier base material could even then be adequately fixed and recovered. Hence, the surface contrast turned out to be the decisive parameter for QR code carrier applicability.

  5. Switchable thulium-doped fiber laser from polarization rotation vector to scalar soliton.

    Science.gov (United States)

    Wu, Zhichao; Fu, Songnian; Jiang, Kai; Song, Jue; Li, Huizi; Tang, Ming; Shum, Ping; Liu, Deming

    2016-10-06

    We experimentally demonstrate switchable temporal soliton generation from a thulium-doped fiber laser (TDFL), using carbon nanotubes as the mode-locker. With the help of residual polarization dependent loss of a wavelength division multiplexer, a weak nonlinear polarization rotation (NPR) effect can be achieved within the laser cavity, which may provide joint contribution for passive mode-locking operation. By finely adjusting the polarization to alter the strength of NPR-based saturable absorption, the TDFL either approaches the operation regime of scalar soliton with strong NPR effect, or generates polarization rotation locked vector soliton (PRLVS) with weak NPR effect. The scalar solitons and PRLVSs possess 3-dB optical spectrum bandwidth of 2.2 nm and 2 nm, pulse-width of 1.8 ps and 2 ps, respectively. Moreover, the PRLVSs demonstrate a typical energy exchange between two polarized components on optical spectra and a period-doubling feature in time domain. Such operation principle can also be used in 1550 nm band fiber lasers and other nonlinear systems.

  6. Durability of switchable QR code carriers under hydrolytic and photolytic conditions

    International Nuclear Information System (INIS)

    Ecker, Melanie; Pretsch, Thorsten

    2013-01-01

    Following a guest diffusion approach, the surface of a shape memory poly(ester urethane) (PEU) was either black or blue colored. Bowtie-shaped quick response (QR) code carriers were then obtained from laser engraving and cutting, before thermo-mechanical functionalization (programming) was applied to stabilize the PEU in a thermo-responsive (switchable) state. The stability of the dye within the polymer surface and long-term functionality of the polymer were investigated against UVA and hydrolytic ageing. Spectrophotometric investigations verified UVA ageing-related color shifts from black to yellow-brownish and blue to petrol-greenish whereas hydrolytically aged samples changed from black to greenish and blue to light blue. In the case of UVA ageing, color changes were accompanied by dye decolorization, whereas hydrolytic ageing led to contrast declines due to dye diffusion. The Michelson contrast could be identified as an effective tool to follow ageing-related contrast changes between surface-dyed and laser-ablated (undyed) polymer regions. As soon as the Michelson contrast fell below a crucial value of 0.1 due to ageing, the QR code was no longer decipherable with a scanning device. Remarkably, the PEU information carrier base material could even then be adequately fixed and recovered. Hence, the surface contrast turned out to be the decisive parameter for QR code carrier applicability. (paper)

  7. Size Switchable Supramolecular Nanoparticle Based on Azobenzene Derivative within Anionic Pillar[5]arene

    Science.gov (United States)

    Zhang, Cai-Cai; Li, Sheng-Hua; Zhang, Cui-Fang; Liu, Yu

    2016-11-01

    A photo/thermal-switchable supramolecular nanoparticles assembly has been constructed based on an inclusion complex between anionic pillar[5]arene 2C-WP5A and azobenzene derivative Azo-py-OMe (G). The novel anionic pillar[5]arene-based host-guest inclusion complexation was investigated by the 1H NMR titration, 2D ROESY and isothermal titration microcalorimetry (ITC) showing high association constant (Ka) of (2.60 ± 0.06) × 104 M-1 with 1:1 binding stoichiometry. Furthermore, the supramolecular nanoparticles assembly can be conveniently obtained from G and a small amount of 2C-WP5A in aqueous solution, which was so-called “host induced aggregating (HIA)”. The size and morphology of the supramolecular nanoparticles assembly were characterized by TEM and DLS. As a result of the photo/thermal-isomerization of G included in the cavity of 2C-WP5A, the size of these nanoparticles could reversibly change from ~800 nm to ~250 nm, which could switch the solution of this assembly from turbid to clear.

  8. A switchable light-input, light-output system modelled and constructed in yeast

    Directory of Open Access Journals (Sweden)

    Kozma-Bognar Laszlo

    2009-09-01

    Full Text Available Abstract Background Advances in synthetic biology will require spatio-temporal regulation of biological processes in heterologous host cells. We develop a light-switchable, two-hybrid interaction in yeast, based upon the Arabidopsis proteins PHYTOCHROME A and FAR-RED ELONGATED HYPOCOTYL 1-LIKE. Light input to this regulatory module allows dynamic control of a light-emitting LUCIFERASE reporter gene, which we detect by real-time imaging of yeast colonies on solid media. Results The reversible activation of the phytochrome by red light, and its inactivation by far-red light, is retained. We use this quantitative readout to construct a mathematical model that matches the system's behaviour and predicts the molecular targets for future manipulation. Conclusion Our model, methods and materials together constitute a novel system for a eukaryotic host with the potential to convert a dynamic pattern of light input into a predictable gene expression response. This system could be applied for the regulation of genetic networks - both known and synthetic.

  9. Charge Modulation in Graphitic Carbon Nitride as a Switchable Approach to High-Capacity Hydrogen Storage.

    Science.gov (United States)

    Tan, Xin; Kou, Liangzhi; Tahini, Hassan A; Smith, Sean C

    2015-11-01

    Electrical charging of graphitic carbon nitride nanosheets (g-C4 N3 and g-C3 N4 ) is proposed as a strategy for high-capacity and electrocatalytically switchable hydrogen storage. Using first-principle calculations, we found that the adsorption energy of H2 molecules on graphitic carbon nitride nanosheets is dramatically enhanced by injecting extra electrons into the adsorbent. At full hydrogen coverage, the negatively charged graphitic carbon nitride achieves storage capacities up to 6-7 wt %. In contrast to other hydrogen storage approaches, the storage/release occurs spontaneously once extra electrons are introduced or removed, and these processes can be simply controlled by switching on/off the charging voltage. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Importantly, g-C4 N3 has good electrical conductivity and high electron mobility, which can be a very good candidate for electron injection/release. These predictions may prove to be instrumental in searching for a new class of high-capacity hydrogen storage materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Mechanically switchable solid inhomogeneous phantom for performance tests in diffuse imaging and spectroscopy.

    Science.gov (United States)

    Pifferi, Antonio; Torricelli, Alessandro; Cubeddu, Rinaldo; Quarto, Giovanna; Re, Rebecca; Sekar, Sanathana K V; Spinelli, Lorenzo; Farina, Andrea; Martelli, Fabrizio; Wabnitz, Heidrun

    2015-12-01

    A mechanically switchable solid inhomogeneous phantom simulating localized absorption changes was developed and characterized. The homogeneous host phantom was made of epoxy resin with black toner and titanium dioxide particles added as absorbing and scattering components, respectively. A cylindrical rod, movable along a hole in the block and made of the same material, has a black polyvinyl chloride cylinder embedded in its center. By varying the volume and position of the black inclusion, absorption perturbations can be generated over a large range of magnitudes. The phantom has been characterized by various time-domain diffuse optics instruments in terms of absorption and scattering spectra, transmittance images, and reflectance contrast. Addressing a major application of the phantom for performance characterization for functional near-infrared spectroscopy of the brain, the contrast was measured in reflectance mode while black cylinders of volumes from ≈20  mm3 to ≈270  mm3 were moved in lateral and depth directions, respectively. The new type of solid inhomogeneous phantom is expected to become a useful tool for routine quality check of clinical instruments or implementation of industrial standards provided an experimental characterization of the phantom is performed in advance.

  11. Synthesis and characterization of a new photoinduced switchable β-cyclodextrin dimer

    Directory of Open Access Journals (Sweden)

    Florian Hamon

    2014-12-01

    Full Text Available This paper reports an efficient preparation of bridged bis-β-CD AZO-CDim 1 bearing azobenzene as a linker and exhibiting high solubility in water. The photoisomerization properties were studied by UV–vis and HPLC and supported by ab initio calculations. The cis/trans ratio of AZO-CDim 1 is 7:93 without irradiation and 37:63 after 120 min of irradiation at 365 nm; the reaction is reversible after irradiation at 254 nm. The photoinduced, switchable binding behavior of AZO-CDim 1 was evaluated by ITC, NMR and molecular modeling in the presence of a ditopic adamantyl guest. The results indicate that AZO-CDim 1 can form two different inclusion complexes with an adamantyl dimer depending on its photoinduced isomers. Both cavities of cis-AZO-CDim 1 are complexed simultaneously by two adamantyl units of the guest forming a 1:1 complex while trans-AZO-CDim 1 seems to lead to the formation of supramolecular polymers with an n:n stoichiometry.

  12. Tunable and switchable dual-wavelength passively mode-locked Bi-doped all-fiber ring laser based on nonlinear polarization rotation

    International Nuclear Information System (INIS)

    Luo, A-P; Luo, Z-C; Xu, W-C; Dvoyrin, V V; Mashinsky, V M; Dianov, E M

    2011-01-01

    We demonstrate a tunable and switchable dual-wavelength passively mode-locked Bi-doped all-fiber ring laser by using nonlinear polarization rotation (NPR) technique. Exploiting the spectral filtering effect caused by the combination of the polarizer and intracavity birefringence, the wavelength separation of dual-wavelength mode-locked pulses can be flexibly tuned between 2.38 and 20.45 nm. Taking the advantage of NPR-induced intensity-dependent loss to suppress the mode competition, the stable dual-wavelength pulses output is obtained at room temperature. Moreover, the dual-wavelength switchable operation is achieved by simply rotating the polarization controllers (PCs)

  13. Conductive Boron-Doped Graphene as an Ideal Material for Electrocatalytically Switchable and High-Capacity Hydrogen Storage.

    Science.gov (United States)

    Tan, Xin; Tahini, Hassan A; Smith, Sean C

    2016-12-07

    Electrocatalytic, switchable hydrogen storage promises both tunable kinetics and facile reversibility without the need for specific catalysts. The feasibility of this approach relies on having materials that are easy to synthesize, possessing good electrical conductivities. Graphitic carbon nitride (g-C 4 N 3 ) has been predicted to display charge-responsive binding with molecular hydrogen-the only such conductive sorbent material that has been discovered to date. As yet, however, this conductive variant of graphitic carbon nitride is not readily synthesized by scalable methods. Here, we examine the possibility of conductive and easily synthesized boron-doped graphene nanosheets (B-doped graphene) as sorbent materials for practical applications of electrocatalytically switchable hydrogen storage. Using first-principle calculations, we find that the adsorption energy of H 2 molecules on B-doped graphene can be dramatically enhanced by removing electrons from and thereby positively charging the adsorbent. Thus, by controlling charge injected or depleted from the adsorbent, one can effectively tune the storage/release processes which occur spontaneously without any energy barriers. At full hydrogen coverage, the positively charged BC 5 achieves high storage capacities up to 5.3 wt %. Importantly, B-doped graphene, such as BC 49 , BC 7 , and BC 5 , have good electrical conductivity and can be easily synthesized by scalable methods, which positions this class of material as a very good candidate for charge injection/release. These predictions pave the route for practical implementation of electrocatalytic systems with switchable storage/release capacities that offer high capacity for hydrogen storage.

  14. A Switchable Molecular Dielectric with Two Sequential Reversible Phase Transitions: [(CH3)4P]4[Mn(SCN)6].

    Science.gov (United States)

    Li, Qiang; Shi, Ping-Ping; Ye, Qiong; Wang, Hui-Ting; Wu, De-Hong; Ye, Heng-Yun; Fu, Da-Wei; Zhang, Yi

    2015-11-16

    A new organic-inorganic hybrid switchable and tunable dielectric compound, [(CH3)4P]4[Mn(SCN)6] (1), exhibits three distinct dielectric states above room temperature and undergoes two reversible solid-state phase transitions, including a structural phase transition at 330 K and a ferroelastic phase transition with the Aizu notation of mmmF2/m at 352 K. The variable-temperature structural analyses disclose that the origin of the phase transitions and dielectric anomalies can be ascribed to the reorientation or motion of both the [(CH3)4P](+) cations and [Mn(SCN)6](4-) anions in solid-state crystals.

  15. A Planar Switchable 3-D-Coverage Phased Array Antenna and Its User Effects for 28-GHz Mobile Terminal Applications

    DEFF Research Database (Denmark)

    Zhang, Shuai; Chen, Xiaoming; Syrytsin, Igor A.

    2017-01-01

    This paper introduces a planar switchable 3D-coverage phased array for 28 GHz mobile terminal applications. In order to realize 3D-coverage beam scan with a simple planar array, chassis surface waves are efficiently excited and controlled by three identical slot subarrays. Three subarrays switch...... their beams to three distinct regions. Each subarray works as a phased array to steer the beam within each region. Large coverage efficiency is achieved (e.g., 80% of the space sphere has the realized gain of over 8 dBi). The proposed antenna covers a bandwidth of over 2 GHz in the band of 28 GHz. User...

  16. Gallium Adhesion: Phase Change of Gallium Enables Highly Reversible and Switchable Adhesion (Adv. Mater. 25/2016).

    Science.gov (United States)

    Ye, Zhou; Lum, Guo Zhan; Song, Sukho; Rich, Steven; Sitti, Metin

    2016-07-01

    M. Sitti and co-workers find that gallium exhibits highly reversible and switchable adhesive characteristics during the liquid-solid phase change. As described on page 5088, this reversible adhesive allows miniature capsule-like robots, which are able to easily pick-and-place objects with irregular geometries and rough surfaces, and thus assemble such objects into a complex structure. The contact interface between gallium and the rough object is illustrated in the magnified image. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Switchable zipper-like thermoresponsive molecularly imprinted polymers for selective recognition and extraction of estradiol.

    Science.gov (United States)

    Xiong, Huihuang; Wu, Xiaqing; Lu, Wenhui; Fu, Junqing; Peng, Hailong; Li, Jinhua; Wang, Xiaoyan; Xiong, Hua; Chen, Lingxin

    2018-01-01

    Zipper-like thermoresponsive molecularly imprinted polymers (MIPs) were prepared based on interpolymer complexation via the synergy of dual functional monomers of acrylamide (AAm) and 2-acrylamide-2-methyl propanesulfonic acid (AMPS) for selective recognition and extraction of estradiol (E2) by temperature regulation. The resulting E2-MIPs attained controlled adsorption and release of E2 in response to temperature change, with higher adsorption capacity (8.78mg/g) and stronger selectivity (imprinting factor was 3.18) at 30°C compared with that at 20 and 40°C; the zipper-like interpolymer interaction between poly(AAm) and poly(AMPS) enabled switchable molecular recognition. The adsorption processes obeyed Langmuir isotherm and pseudo-second-order kinetic models. High recognition selectivity of the MIPs toward E2 was achieved over its structural analogues, and good reusability was displayed over 86% recovery after six adsorption-desorption cycles. Accordingly, the E2-MIPs were empolyed as new adsorbents for selective dispersive solid-phase extraction of E2, and offered low limits of detection and quantification of 4.81 and 16.03μg/L, respectively. Recoveries from goat milk samples ranged from 76.2% to 89.7% with the precisions (relative standard deviations, n = 3, %) of 2.8-3.7% at 30°C. The intelligent E2-MIPs combining good adsorption, special recognition and temperature sensitivity proved to be a promising alternative to the selective identification and controlled extraction/removal of E2 in complicated samples by simple temperature-responsive regulation. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Trapping of quantum particles and light beams by switchable potential wells

    Science.gov (United States)

    Sonkin, Eduard; Malomed, Boris A.; Granot, Er'El; Marchewka, Avi

    2010-09-01

    We consider basic dynamical effects in settings based on a pair of local potential traps that may be effectively switched on and off, or suddenly displaced, by means of appropriate control mechanisms, such as scanning tunneling microscopy or photo-switchable quantum dots. The same models, based on the linear Schrödinger equation with time-dependent trapping potentials, apply to the description of optical planar systems designed for the switching of trapped light beams. The analysis is carried out in the analytical form, using exact solutions of the Schrödinger equation. The first dynamical problem considered in this work is the retention of a particle released from a trap which was suddenly turned off, while another local trap was switched on at a distance—immediately or with a delay. In this case, we demonstrate that the maximum of the retention rate is achieved at a specific finite value of the strength of the new trap, and at a finite value of the temporal delay, depending on the distance between the two traps. Another problem is retrapping of the bound particle when the addition of the second trap transforms the single-well setting into a double-well potential (DWP). In that case, we find probabilities for the retrapping into the ground or first excited state of the DWP. We also analyze effects entailed by the application of a kick to a bound particle, the most interesting one being a kick-induced transition between the DWP’s ground and excited states. In the latter case, the largest transition probability is achieved at a particular strength of the kick.

  19. Virtual screening on an α-helix to β-strand switchable region of the FGFR2 extracellular domain revealed positive and negative modulators.

    Science.gov (United States)

    Diaz, Constantino; Corentin, Herbert; Thierry, Vermat; Chantal, Alcouffe; Tanguy, Bozec; David, Sibrac; Jean-Marc, Herbert; Pascual, Ferrara; Françoise, Bono; Edgardo, Ferran

    2014-11-01

    The secondary structure of some protein segments may vary between α-helix and β-strand. To predict these switchable segments, we have developed an algorithm, Switch-P, based solely on the protein sequence. This algorithm was used on the extracellular parts of FGF receptors. For FGFR2, it predicted that β4 and β5 strands of the third Ig-like domain were highly switchable. These two strands possess a high number of somatic mutations associated with cancer. Analysis of PDB structures of FGF receptors confirmed the switchability prediction for β5. We thus evaluated if compound-driven α-helix/β-strand switching of β5 could modulate FGFR2 signaling. We performed the virtual screening of a library containing 1.4 million of chemical compounds with two models of the third Ig-like domain of FGFR2 showing different secondary structures for β5, and we selected 32 compounds. Experimental testing using proliferation assays with FGF7-stimulated SNU-16 cells and a FGFR2-dependent Erk1/2 phosphorylation assay with FGFR2-transfected L6 cells, revealed activators and inhibitors of FGFR2. Our method for the identification of switchable proteinic regions, associated with our virtual screening approach, provides an opportunity to discover new generation of drugs with under-explored mechanism of action. © 2014 Wiley Periodicals, Inc.

  20. Smart candle soot coated membranes for on-demand immiscible oil/water mixture and emulsion switchable separation.

    Science.gov (United States)

    Li, Jian; Zhao, Zhihong; Li, Dianming; Tian, Haifeng; Zha, Fei; Feng, Hua; Guo, Lin

    2017-09-21

    Oil/water separation is of great importance for the treatment of oily wastewater, including immiscible light/heavy oil-water mixtures, oil-in-water or water-in-oil emulsions. Smart surfaces with responsive wettability have received extensive attention especially for controllable oil/water separation. However, traditional smart membranes with a switchable wettability between superhydrophobicity and superhydrophilicity are limited to certain responsive materials and continuous external stimuli, such as pH, electrical field or light irradiation. Herein, a candle soot coated mesh (CSM) with a larger pore size and a candle soot coated PVDF membrane (CSP) with a smaller pore size with underwater superoleophobicity and underoil superhydrophobicity were successfully fabricated, which can be used for on-demand immiscible oil/water mixtures and surfactants-stabilized oil/water emulsion separation, respectively. Without any continuous external stimulus, the wettability of our membranes could be reversibly switched between underwater superoleophobicity and underoil superhydrophobicity simply by drying and washing alternately, thus achieving effective and switchable oil/water separation with excellent separation efficiency. We believe that such smart materials will be promising candidates for use in the removal of oil pollutants in the future.

  1. Mechanism(s) for the suppression of the switchable polarization in PZT and BaTiO3

    Science.gov (United States)

    Warren, William L.; Dimos, Duane; Tuttle, Bruce A.; Pike, Gordon E.; Raymond, Mark V.; Nasby, Robert D.; Ramesh, R.; Evans, Joseph T., Jr.

    Switchable polarization can be significantly suppressed in ferroelectric (FE) materials by optical, thermal, and electrical processes. The thermal process can occur by either annealing the FE in a reducing environment or by heating it in air to 100 C while impressing a bias near the switching threshold. The optical process occurs while biasing the FE near the switching threshold and illuminating with bandgap light. And the electrical suppression effect occurs by subjecting the FE to repeated polarization reversals. Using electron paramagnetic resonance, polarization-voltage measurements, and charge injection scenarios, the authors have been able to elucidate both electronic and ionic trapping effects that lead to a suppression in the amount of switchable polarization in FE materials. The relative roles of electronic and ionic effects in the same material can depend on the stress condition. For instance, in oxidized BaTiO3 crystals, optical and thermal suppressions occur by electronic domain pinning; electrical fatigue in the BaTiO3 crystals also appears to involve electronic charge trapping, however, it is suggested that these electronic traps are further stabilized by nearby ionic defects. In sol-gel PZT thin films with either Pt, RuO2, or La-Sr-Co-O electrodes it appears that the polarization suppression induced by electrical fatigue, a temperature/bias combination, or a light/bias combination are all primarily due to the trapping of electronic charge carriers to first order.

  2. Coupled transfers; Transferts couples

    Energy Technology Data Exchange (ETDEWEB)

    Nicolas, X.; Lauriat, G.; Jimenez-Rondan, J. [Universite de Marne-la-Vallee, Lab. d' Etudes des Transferts d' Energie et de Matiere (LETEM), 77 (France); Bouali, H.; Mezrhab, A. [Faculte des Sciences, Dept. de Physique, Lab. de Mecanique et Energetique, Oujda (Morocco); Abid, C. [Ecole Polytechnique Universitaire de Marseille, IUSTI UMR 6595, 13 Marseille (France); Stoian, M.; Rebay, M.; Lachi, M.; Padet, J. [Faculte des Sciences, Lab. de Thermomecanique, UTAP, 51 - Reims (France); Mladin, E.C. [Universitaire Polytechnique Bucarest, Faculte de Genie Mecanique, Bucarest (Romania); Mezrhab, A. [Faculte des Sciences, Lab. de Mecanique et Energetique, Dept. de Physique, Oujda (Morocco); Abid, C.; Papini, F. [Ecole Polytechnique, IUSTI, 13 - Marseille (France); Lorrette, C.; Goyheneche, J.M.; Boechat, C.; Pailler, R. [Laboratoire des Composites ThermoStructuraux, UMR 5801, 33 - Pessac (France); Ben Salah, M.; Askri, F.; Jemni, A.; Ben Nasrallah, S. [Ecole Nationale d' Ingenieurs de Monastir, Lab. d' Etudes des Systemes Thermiques et Energetiques (Tunisia); Grine, A.; Desmons, J.Y.; Harmand, S. [Laboratoire de Mecanique et d' Energetique, 59 - Valenciennes (France); Radenac, E.; Gressier, J.; Millan, P. [ONERA, 31 - Toulouse (France); Giovannini, A. [Institut de Mecanique des Fluides de Toulouse, 31 (France)

    2005-07-01

    This session about coupled transfers gathers 30 articles dealing with: numerical study of coupled heat transfers inside an alveolar wall; natural convection/radiant heat transfer coupling inside a plugged and ventilated chimney; finite-volume modeling of the convection-conduction coupling in non-stationary regime; numerical study of the natural convection/radiant heat transfer coupling inside a partitioned cavity; modeling of the thermal conductivity of textile reinforced composites: finite element homogenization on a full periodical pattern; application of the control volume method based on non-structured finite elements to the problems of axisymmetrical radiant heat transfers in any geometries; modeling of convective transfers in transient regime on a flat plate; a conservative method for the non-stationary coupling of aero-thermal engineering codes; measurement of coupled heat transfers (forced convection/radiant transfer) inside an horizontal duct; numerical simulation of the combustion of a water-oil emulsion droplet; numerical simulation study of heat and mass transfers inside a reactor for nano-powders synthesis; reduction of a combustion and heat transfer model of a direct injection diesel engine; modeling of heat transfers inside a knocking operated spark ignition engine; heat loss inside an internal combustion engine, thermodynamical and flamelet model, composition effects of CH{sub 4}H{sub 2} mixtures; experimental study and modeling of the evolution of a flame on a solid fuel; heat transfer for laminar subsonic jet of oxygen plasma impacting an obstacle; hydrogen transport through a A-Si:H layer submitted to an hydrogen plasma: temperature effects; thermal modeling of the CO{sub 2} laser welding of a magnesium alloy; radiant heat transfer inside a 3-D environment: application of the finite volume method in association with the CK model; optimization of the infrared baking of two types of powder paints; optimization of the emission power of an infrared

  3. A qubit strongly coupled to a resonant cavity: asymmetry of the spontaneous emission spectrum beyond the rotating wave approximation

    Energy Technology Data Exchange (ETDEWEB)

    Cao, X [Department of Physics and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, 361005 (China); You, J Q; Nori, F [Advanced Science Institute, RIKEN, Wako-shi 351-0198 (Japan); Zheng, H, E-mail: xfcao@xmu.edu.cn [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2011-07-15

    We investigate the spontaneous emission (SE) spectrum of a qubit in a lossy resonant cavity. We use neither the rotating-wave approximation nor the Markov approximation. For the weak-coupling case, the SE spectrum of the qubit is a single peak, with its location depending on the spectral density of the qubit environment. Then, the asymmetry (of the location and heights of the two peaks) of the two SE peaks (which are related to the vacuum Rabi splitting) changes as the qubit-cavity coupling increases. Explicitly, for a qubit in a low-frequency intrinsic bath, the height asymmetry of the splitting peaks is enhanced as the qubit-cavity coupling strength increases. However, for a qubit in an Ohmic bath, the height asymmetry of the spectral peaks is inverted compared to the low-frequency bath case. With further increasing the qubit-cavity coupling to the ultra-strong regime, the height asymmetry of the left and right peaks is slightly inverted, which is consistent with the corresponding case of a low-frequency bath. This inversion of the asymmetry arises from the competition between the Ohmic bath and the cavity bath. Therefore, after considering the anti-rotating terms, our results explicitly show how the height asymmetry in the SE spectrum peaks depends on the qubit-cavity coupling and the type of intrinsic noise experienced by the qubit.

  4. Reversed thermo-switchable molecular sieving membranes composed of two-dimensional metal-organic nanosheets for gas separation.

    Science.gov (United States)

    Wang, Xuerui; Chi, Chenglong; Zhang, Kang; Qian, Yuhong; Gupta, Krishna M; Kang, Zixi; Jiang, Jianwen; Zhao, Dan

    2017-02-16

    It is highly desirable to reduce the membrane thickness in order to maximize the throughput and break the trade-off limitation for membrane-based gas separation. Two-dimensional membranes composed of atomic-thick graphene or graphene oxide nanosheets have gas transport pathways that are at least three orders of magnitude higher than the membrane thickness, leading to reduced gas permeation flux and impaired separation throughput. Here we present nm-thick molecular sieving membranes composed of porous two-dimensional metal-organic nanosheets. These membranes possess pore openings parallel to gas concentration gradient allowing high gas permeation flux and high selectivity, which are proven by both experiment and molecular dynamics simulation. Furthermore, the gas transport pathways of these membranes exhibit a reversed thermo-switchable feature, which is attributed to the molecular flexibility of the building metal-organic nanosheets.

  5. Thermally switchable meta-material absorber involving vanadium dioxide semiconductor–metal transition for thermo photovoltaic conversion

    Science.gov (United States)

    Bendelala, Fathi; Cheknane, Ali; Hilal, Hikmat S.

    2018-01-01

    A new switchable absorber design using meta-materials for thermo photovoltaic applications is proposed here. Conventional absorbents are normally non-adjustable with narrow band-widths and polarization-dependence. The present study describes an alternative infrared absorber structure with tunable characteristics. The absorber is based on VO2 which exhibits transition from semiconductor to metallic conductor by thermal effect. With this design, the results show that wide-band absorption can be achieved. The absorption bandwidth can be improved from 15.94 to 36.75 THz. With 40.42% relative shift in the peak frequency, a maximum absorption efficiency of 99% can be achieved. This structure design is polarization-independent of normal incident radiations, and may accommodate radiations from wide oblique angles. These new features make the new thermally adjustable absorber potentially useful in thermo-photovoltaic conversion devices.

  6. Fluoropolymer/SiO2 composite films with switchable superoleophilicity and high oleophobicity for “on–off” oil permeation

    International Nuclear Information System (INIS)

    Yang, Hao; Hu, Xiaojing; Chen, Rong; Liu, Shantang; Pi, Pihui; Yang, Zhuo-ru

    2013-01-01

    In this work, fluoropolymer/SiO 2 composite films with switchable superoleophilicity and high oleophobicity have been successfully prepared on stainless steel mesh. Tunable wettability could be easily realized by merely reversing the feeding order of the perfluorinated monomer in the polymerization. The effects of surface roughness and chemical composition on the wettability of the films were investigated by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results indicate that the distribution of low surface energy groups plays a crucial role in determining the surface oleophobicity or oleophilicity. The porous stainless steel mesh with fluoropolymer/SiO 2 composite could construct dual-scale roughness, leading to less wetting of the solid. The stainless steel mesh coated with the proposed as-prepared polymer films may lead to an oil–water separation membrane. This work provides an interesting insight into the design of novel functional devices that are relevant to oil/water separation.

  7. Reversed thermo-switchable molecular sieving membranes composed of two-dimensional metal-organic nanosheets for gas separation

    Science.gov (United States)

    Wang, Xuerui; Chi, Chenglong; Zhang, Kang; Qian, Yuhong; Gupta, Krishna M.; Kang, Zixi; Jiang, Jianwen; Zhao, Dan

    2017-02-01

    It is highly desirable to reduce the membrane thickness in order to maximize the throughput and break the trade-off limitation for membrane-based gas separation. Two-dimensional membranes composed of atomic-thick graphene or graphene oxide nanosheets have gas transport pathways that are at least three orders of magnitude higher than the membrane thickness, leading to reduced gas permeation flux and impaired separation throughput. Here we present nm-thick molecular sieving membranes composed of porous two-dimensional metal-organic nanosheets. These membranes possess pore openings parallel to gas concentration gradient allowing high gas permeation flux and high selectivity, which are proven by both experiment and molecular dynamics simulation. Furthermore, the gas transport pathways of these membranes exhibit a reversed thermo-switchable feature, which is attributed to the molecular flexibility of the building metal-organic nanosheets.

  8. A tunable and switchable single-longitudinal-mode dual-wavelength fiber laser with a simple linear cavity.

    Science.gov (United States)

    He, Xiaoying; Fang, Xia; Liao, Changrui; Wang, D N; Sun, Junqiang

    2009-11-23

    A simple linear cavity erbium-doped fiber laser based on a Fabry-Perot filter which consists of a pair of fiber Bragg gratings is proposed for tunable and switchable single-longitudinal-mode dual-wavelength operation. The single-longitudinal-mode is obtained by the saturable absorption of an unpumed erbium-doped fiber together with a narrow-band fiber Bragg grating. Under the high pump power (>166 mW) condition, the stable dual-wavelength oscillation with uniform amplitude can be realized by carefully adjusting the polarization controller in the cavity. Wavelength selection and switching are achieved by tuning the narrow-band fiber Bragg grating in the system. The spacing of the dual-wavelength can be selected at 0.20 nm (approximately 25.62 GHz), 0.22 nm (approximately 28.19 GHz) and 0.54 nm (approximately 69.19 GHz).

  9. Chitosan-Gated Magnetic-Responsive Nanocarrier for Dual-Modal Optical Imaging, Switchable Drug Release, and Synergistic Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hui [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA; Mu, Qingxin [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA; Revia, Richard [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA; Wang, Kui [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA; Zhou, Xuezhe [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA; Pauzauskie, Peter J. [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA; Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland WA 99354 USA; Zhou, Shuiqin [Department of Chemistry, The College of Staten Island, City University of New York, Staten Island NY 10314 USA; Zhang, Miqin [Department of Materials Science and Engineering, University of Washington, Seattle WA 98195 USA

    2017-01-25

    In this study, we present a multifunctional yet structurally simple nanocarrier that has a high drug loading capacity, releases drug in response to onset of an AC magnetic field, and can serve as a long-term imaging contrast agent and effectively kills cancer cells by synergistic action. This nanocarrier (HMMC-NC) has a spherical shell structure with a center cavity of 80 nm in diameter. The shell is comprised of two layers: an inner layer of magnetite that exhibits superparamagnetism and an outer layer of mesoporous carbon embedded with carbon dots that exhibit photoluminescence property. Thus in addition to being a drug carrier, HMMC-NC is also a contrast agent for bioimaging. The switchable drug release is enabled by the chitosan molecules attached on the nanocarrier as the switching material which turns on or off the drug release in response to the application or withdrawal of an AC magnetic field.

  10. Spectral study on conformation switchable cationic calix[4]carbazole serving as curcumin container, stabilizer and sustained-delivery carrier

    Science.gov (United States)

    Zhao, Liang; Kang, Le; Chen, Yan; Li, Gang; Wang, Lan; Hu, Chun; Yang, Peng

    2018-03-01

    A fluorescent 2,7-dimethoxy-substituted calix[4]carbazole (1) is facilely synthesized. The spectral behaviors of both the guest-induced switchable conformation of 1 and its abilities serving as the stabilizer and molecular carrier of curcumin are investigated. UV-vis, fluorescence and NMR spectral results show that upon binding to curcumin, the 1,3-alternate conformation of 1 is converted to be the cone one. The relative high association constant (6.4 × 106 M- 1) of 1 binding to curcumin enables it to stabilize the curcumin, to suppress its degradation, and to sustainably deliver it into the EYPC vesicles within 20 h. Moreover, the cytotoxicity assay shows that 1 does not interfere the antiproliferative activities of curcumin. All these properties endow 1 the potential capability of serving as the molecular drug carrier. Our current result may pave the way looking for more efficient fluorescent calixcarbazoles and thereof spectral utilities.

  11. Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications.

    Science.gov (United States)

    Eom, Seung-Hyun; Seo, Yunsik; Lim, Sungjoon

    2015-12-10

    In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT) switch and a balun element. A double-sided parallel-strip line (DSPSL) is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antennas have different radiation patterns because of the different orientation of the reflectors and antennas. It is demonstrated from electromagnetic (EM) simulation and measurement that the radiation patterns of the proposed antenna are successfully switched by the SPDT switch.

  12. Produced Water Treatment Using the Switchable Polarity Solvent Forward Osmosis (SPS FO) Desalination Process: Preliminary Engineering Design Basis

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, Daniel; Adhikari, Birendra; Orme, Christopher; Wilson, Aaron

    2016-05-01

    Switchable Polarity Solvent Forward Osmosis (SPS FO) is a semi-permeable membrane-based water treatment technology. INL is currently advancing SPS FO technology such that a prototype unit can be designed and demonstrated for the purification of produced water from oil and gas production operations. The SPS FO prototype unit will used the thermal energy in the produced water as a source of process heat, thereby reducing the external process energy demands. Treatment of the produced water stream will reduce the volume of saline wastewater requiring disposal via injection, an activity that is correlated with undesirable seismic events, as well as generate a purified product water stream with potential beneficial uses. This paper summarizes experimental data that has been collected in support of the SPS FO scale-up effort, and describes how this data will be used in the sizing of SPS FO process equipment. An estimate of produced water treatment costs using the SPS FO process is also provided.

  13. Advances in quantum control of three-level superconducting circuit architectures

    Energy Technology Data Exchange (ETDEWEB)

    Falci, G.; Paladino, E. [Dipartimento di Fisica e Astronomia, Universita di Catania (Italy); CNR-IMM UOS Universita (MATIS), Consiglio Nazionale delle Ricerche, Catania (Italy); INFN, Sezione di Catania (Italy); Di Stefano, P.G. [Dipartimento di Fisica e Astronomia, Universita di Catania (Italy); Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Queen' s University Belfast(United Kingdom); Ridolfo, A.; D' Arrigo, A. [Dipartimento di Fisica e Astronomia, Universita di Catania (Italy); Paraoanu, G.S. [Low Temperature Laboratory, Department of Applied Physics, Aalto University School of Science (Finland)

    2017-06-15

    Advanced control in Lambda (Λ) scheme of a solid state architecture of artificial atoms and quantized modes would allow the translation to the solid-state realm of a whole class of phenomena from quantum optics, thus exploiting new physics emerging in larger integrated quantum networks and for stronger couplings. However control solid-state devices has constraints coming from selection rules, due to symmetries which on the other hand yield protection from decoherence, and from design issues, for instance that coupling to microwave cavities is not directly switchable. We present two new schemes for the Λ-STIRAP control problem with the constraint of one or two classical driving fields being always-on. We show how these protocols are converted to apply to circuit-QED architectures. We finally illustrate an application to coherent spectroscopy of the so called ultrastrong atom-cavity coupling regime. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Required Equipment for Photo-Switchable Donor-Acceptor (D-A) Dyad Interfacial Self-Assembled Monolayers for Organic Photovoltaic Cells

    Science.gov (United States)

    2014-01-24

    Accessory, 6) a Jelight Co. UVO cleaner, and 7) a Laurell Technologies Spin Coater . These instruments were used to characterize a variety of...goniometer/tensiometer, UVO cleaner, spin coater U U U UU Luis Echegoyen (915) 747-7573 (HBCU) - Required Equipment for Photo-switchable Donor...are exposed to the spin coated photoactive layer over the ITO monolayer, the effectiveness of this monolayer will be difficult to study. We need

  15. Polymeric microcapsules with switchable mechanical properties for self-healing concrete: synthesis, characterisation and proof of concept

    Science.gov (United States)

    Kanellopoulos, A.; Giannaros, P.; Palmer, D.; Kerr, A.; Al-Tabbaa, A.

    2017-04-01

    Microcapsules, with sodium silicate solution as core, were produced using complex coacervation in a double, oil-in-water-in oil, emulsion system. The shell material was a gelatin-acacia gum crosslinked coacervate and the produced microcapsules had diameters ranging from 300 to 700 μm. The shell material designed with switchable mechanical properties. When it is hydrated exhibits soft and ‘rubbery’ behaviour and, when dried, transitions to a stiff and ‘glassy’ material. The microcapsules survived drying and rehydrating cycles and preserved their structural integrity when exposed to highly alkaline solutions that mimic the pH environment of concrete. Microscopy revealed that the shell thickness of the microcapsules varies across their perimeter from 5 to 20 μm. Thermal analysis showed that the produced microcapsules were very stable up to 190 °C. Proof of concept investigation has demonstrated that the microcapsules successfully survive and function when exposed to a cement-based matrix. Observations showed that the microcapsules survive mixing with cement and rupture successfully upon crack formation releasing the encapsulated sodium silicate solution.

  16. Polypropylene Nonwoven Fabric@Poly(ionic liquid)s for Switchable Oil/Water Separation, Dye Absorption, and Antibacterial Applications.

    Science.gov (United States)

    Ren, Yongyuan; Guo, Jiangna; Lu, Qian; Xu, Dan; Qin, Jing; Yan, Feng

    2018-03-22

    Pollutants in wastewater include oils, dyes, and bacteria, making wastewater cleanup difficult. Multifunctional wastewater treatment media consisting of poly(ionic liquid)-grafted polypropylene (PP) nonwoven fabrics (PP@PIL) are prepared by a simple and scalable surface-grafting process. The fabricated PP@PIL fabrics exhibit impressive switchable oil/water separation (η>99 %) and dye absorption performance (q=410 mg g -1 ), as well as high antibacterial properties. The oil/water separation can be easily switched by anion exchanging of the PIL segments. Moreover, the multiple functions (oil/water separation, dye absorption, and antibacterial properties) occurred at the same time, and did not interfere with each other. The multifunctional fibrous filter can be easily regenerated by washing with an acid solution, and the absorption capacity is maintained after many recycling tests. These promising features make PIL-grafted PP nonwoven fabric a potential one-step treatment for multicomponent wastewater. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Coordinate-targeted and coordinate-stochastic super-resolution microscopy with the reversibly switchable fluorescent protein Dreiklang.

    Science.gov (United States)

    Jensen, Nickels A; Danzl, Johann G; Willig, Katrin I; Lavoie-Cardinal, Flavie; Brakemann, Tanja; Hell, Stefan W; Jakobs, Stefan

    2014-03-17

    Diffraction-unlimited far-field super-resolution fluorescence (nanoscopy) methods typically rely on transiently transferring fluorophores between two states, whereby this transfer is usually laid out as a switch. However, depending on whether this is induced in a spatially controlled manner using a pattern of light (coordinate-targeted) or stochastically on a single-molecule basis, specific requirements on the fluorophores are imposed. Therefore, the fluorophores are usually utilized just for one class of methods only. In this study we demonstrate that the reversibly switchable fluorescent protein Dreiklang enables live-cell recordings in both spatially controlled and stochastic modes. We show that the Dreiklang chromophore entails three different light-induced switching mechanisms, namely a reversible photochemical one, off-switching by stimulated emission, and a reversible transfer to a long-lived dark state from the S1 state, all of which can be utilized to overcome the diffraction barrier. We also find that for the single-molecule-based stochastic GSDIM approach (ground-state depletion followed by individual molecule return), Dreiklang provides a larger number of on-off localization events as compared to its progenitor Citrine. Altogether, Dreiklang is a versatile probe for essentially all popular forms of live-cell fluorescence nanoscopy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. A versatile light-switchable nanorod memory: Wurtzite ZnO on perovskite SrTiO3

    KAUST Repository

    Kumar, Anup Bera

    2013-04-25

    Integrating materials with distinct lattice symmetries and dimensions is an effective design strategy toward realizing novel devices with unprecedented functionalities, but many challenges remain in synthesis and device design. Here, a heterojunction memory made of wurtzite ZnO nanorods grown on perovskite Nb-doped SrTiO3 (NSTO) is reported, the electronic properties of which can be drastically reconfigured by applying a voltage and light. Despite of the distinct lattice structures of ZnO and NSTO, a consistent nature of single crystallinity is achieved in the heterojunctions via the low-temperature solution-based hydrothermal growth. In addition to a high and persistent photoconductivity, the ZnO/NSTO heterojunction diode can be turned into a versatile light-switchable resistive switching memory with highly tunable ON and OFF states. The reversible modification of the effective interfacial energy barrier in the concurrent electronic and ionic processes most likely gives rise to the high susceptibility of the ZnO/NSTO heterojunction to external electric and optical stimuli. Furthermore, this facile synthesis route is promising to be generalized to other novel functional nanodevices integrating materials with diverse structures and properties. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Isolation and characterization of a novel Rhodococcus strain with switchable carbonyl reductase and para-acetylphenol hydroxylase activities.

    Science.gov (United States)

    Zhang, Rui; Ren, Jie; Wang, Yu; Wu, Qiaqing; Wang, Min; Zhu, Dunming

    2013-01-01

    In the search for an effective biocatalyst for the reduction of acetophenones with unprotected hydroxy group on the benzene ring, a microorganism, which reduced para-acetylphenol to S-(-)-1-(para-hydroxyphenyl)ethanol under anaerobic conditions, was isolated from soil samples and the 16S rDNA study showed that it was phylogenetically affiliated with species of the genus Rhodococcus and was most similar to Rhodococcus pyridinivorans. Unexpectedly, this strain also hydroxylated para-acetylphenol to give 4-acetylcatechol in presence of oxygen, possessing para-acetylphenol hydroxylase activity. While the reduction of para-acetylphenol had an optimal reaction pH at 7 and a broad optimal temperature range (35-45 °C), the hydroxylation reached the maximum conversion at the pH range of 7-8 and 35 °C. This study identified for the first time a Rhodococcus strain with para-acetylphenol hydroxylase activity, which also contains highly enantioselective carbonyl reductase activity with potential applications for the asymmetric reduction of these less-explored but important ketones such as α-aminoacetophenone, 3'-hydroxyacetophenone and 4'-hydroxyacetophenone. The para-acetylphenol hydroxylase and carbonyl reductase activity are switchable by the reaction conditions.

  20. Synthesis of conformation switchable cationic polypeptides based on poly(S-propargyl-cysteine) for use as siRNA delivery.

    Science.gov (United States)

    Yi, Ling; Wang, Yisi; Lin, Guanliang; Lin, Danling; Chen, Wenliang; Huang, Yugang; Ye, Guodong

    2017-08-01

    Ring-opening polymerization of S-propargyl-cysteine-N-carboxyanhydride has been used to synthesize conformation switchable poly(S-propargyl-cysteine) starting with l-cysteine, dl- and d-cysteine. Then cationic polypeptides with different backbone chirality are obtained by nearly 100% side-chain grafting of cysteamine via thiol-yne click chemistry. The cationic polypeptides containing mixed conformations of β-sheets, β-turns and random coils are stable against pH, salt and temperature variations. The cationic polypeptides can condense siRNA at a low polypeptide/siRNA weight ratio to form nanoparticles with size depending on the backbone chirality. The cationic polypeptides derived from poly(S-propargyl-l or d-cysteine) are non-cytotoxic to HeLa and HepG2 cells, but interrupting the backbone chirality enhances the cytotoxicity sharply. The cationic polypeptides used for siRNA delivery show good transfection efficiency, but cell internalization process depends on the backbone chirality. The cationic polypeptide derived from the poly(S-propargyl-l-cysteine) is an appropriate siRNA vector with advantages of non-cytotoxicity and high transfection efficiency. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Smart multifunctional nanoagents for in situ monitoring of small molecules with a switchable affinity towards biomedical targets

    Science.gov (United States)

    Shevchenko, Konstantin G.; Cherkasov, Vladimir R.; Nikitina, Irina L.; Babenyshev, Andrey V.; Nikitin, Maxim P.

    2018-02-01

    The great diversity of nanomaterials provides ample opportunities for constructing effective agents for biomedical applications ranging from biosensing to drug delivery. Multifunctional nanoagents that combine several features in a single particle are of special interest due to capabilities that substantially exceed those of molecular drugs. An ideal theranostic agent should simultaneously be an advanced biosensor to identify a disease and report the diagnosis and a biomedical actuator to treat the disease. While many approaches were developed to load a nanoparticle with various drugs for actuation of the diseased cells (e.g., to kill them), the nanoparticle-based approaches for the localized biosensing with real-time reporting of the marker concentration severely lag behind. Here, we show a smart in situ nanoparticle-based biosensor/actuator system that dynamically and reversibly changes its structural and optical properties in response to a small molecule marker to allow real-time monitoring of the marker concentration and adjustment of the system ability to bind its biomedical target. Using the synergistic combination of signal readout based on the localized surface plasmon resonance and an original method of fabrication of smart ON/OFF-switchable nanoagents, we demonstrate reversible responsiveness of the system to a model small molecule marker (antibiotic chloramphenicol) in a wide concentration range. The proposed approach can be used for the development of advanced multifunctional nanoagents for theranostic applications.

  2. Characterization of Anthraquinone-DerivedRedox Switchable Ionophores and Their Complexes with Li+, Na+, K+, Ca+, and Mg+ Metal Ions

    Directory of Open Access Journals (Sweden)

    Vaishali Vyas

    2011-01-01

    Full Text Available Anthraquinone derived redox switchable ionophores 1,5 bis (2-(2-(2-ethoxy ethoxy ethoxyanthracene-9,10-dione (V1 and 1,8-bis(2-(2-(2-ethoxyethoxyethoxy anthracene—9,10-dione (V2 have been used for isolation, extraction and liquid membrane transport studies of Li+, Na+, K+, Ca2+ and Mg2+ metal ions. These isolated complexes were characterized by melting point determination, CV and IR, 1H NMR spectral analysis. Ionophore V2 shows maximum shift in reduction potential (ΔE with Ca(Pic2. The observed sequence for the shifting in reduction potential (ΔE between V2 and their complexes is V2 calcium picrate (42 mV > V2 potassium picrate (33 mV > V2 lithium picrate (25 mV > V2 sodium picrate (18 mV > V2 magnesium picrate (15 mV. These findings are also supported by results of extraction, back extraction and transport studies. Ionophore V2 complexed with KPic and showed much higher extractability and selectivity towards K+ than V1. These synthetic ionophores show positive and negative cooperativity towards alkali and alkaline earth metal ions in reduced and oxidized state. Hence, this property can be used in selective separation and enrichment of metal ions using electrochemically driven ion transport.

  3. Coupling Magnetism to Electricity in Multiferroic Heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Ramesh, R [U.S. DOE

    2012-02-15

    Complex perovskite oxides exhibit a rich spectrum of functional responses, including magnetism, ferroelectricity, highly correlated electron behavior, superconductivity, etc. The basic materials physics of such materials provide the ideal playground for interdisciplinary scientific exploration. Over the past decade we have been exploring the science of such materials (for example, colossal magnetoresistance, ferroelectricity, etc) in thin-film form by creating epitaxial heterostructures and nanostructures. Among the large number of materials systems, there exists a small set of materials which exhibit multiple order parameters; these are known as multiferroics. Using our work in the field of ferroelectric and ferromagnetic oxides as the background, we are now exploring such materials as epitaxial thin films, as well as nanostructures. Specifically, we are studying the role of thin-film growth, heteroepitaxy, and processing on the basic properties as well as the magnitude of the coupling between the order parameters. In our work we are exploring the switchability of the antiferromagnetic order using this coupling. What is the importance of this work? Antiferromagnets are pervasive in the recording industry. They are used as exchange biasing layers in magnetic tunnel junctions, etc. However, to date there has been no antiferomagnet that is electrically tunable. We believe that the multiferroic BiFeO3 is one compound where this can be observed at room temperature. The next step is to explore the coupling of a ferromagnet to this antiferromagnet through the exchange biasing concept. Ultimately, this will give us the opportunity to switch the magnetic state in a ferromagnet (and therefore the spin polarization direction) by simply applying an electric field to the underlying antiferromagnetic ferroelectric. In this talk, I will describe our progress to date on this exciting possibility.

  4. Direct Imaging of Charge Density Modulation in Switchable Two-Dimensional Electron Gas at the Oxide Hetero-Interfaces by Using Electron Bean Inline Holography

    Science.gov (United States)

    2015-08-16

    Switchable Two-Dimensional Electron Gas at the Oxide Hetero-Interfaces by Using Electron Bean Inline Holography 5a. CONTRACT NUMBER FA2386-13-1-4136...directly imaged the charge carrier densities and spatial distributions at the (001) LaAlO3/SrTiO3 heterointerfaces by in-situ TEM holography . The new...Hetero-Interfaces by Using Electron Bean Inline Holography 5a. CONTRACT NUMBER FA2386-13-1-4136 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 61102F

  5. Magnetoresponsive Poly(ether sulfone)-Based Iron Oxide cum Hydrogel Mixed Matrix Composite Membranes for Switchable Molecular Sieving.

    Science.gov (United States)

    Lin, Xi; Nguyen Quoc, Bao; Ulbricht, Mathias

    2016-10-26

    Stimuli-responsive membranes that can adjust mass transfer and interfacial properties "on demand" have drawn large interest over the last few decades. Here, we designed and prepared a novel magnetoresponsive separation membrane with remote switchable molecular sieving effect by simple one-step and scalable nonsolvent induced phase separation (NIPS) process. Specifically, poly(ether sulfone) (PES) as matrix for an anisotropic membrane, prefabricated poly(N-isopropylacrylamide) (PNIPAAm) nanogel (NG) particles as functional gates, and iron oxide magnetic nanoparticles (MNP) as localized heaters were combined in a synergistic way. Before membrane casting, the properties of the building blocks, including swelling property and size distribution for NG, and magnetic property and heating efficiency for MNP, were investigated. Further, to identify optimal film casting conditions for membrane preparation by NIPS, in-depth rheological study of the effects of composition and temperature on blend dope solutions was performed. At last, a composite membrane with 10% MNP and 10% NG blended in a porous PES matrix was obtained, which showed a large, reversible, and stable magneto-responsivity. It had 9 times higher water permeability at the "on" state of alternating magnetic field (AMF) than at the "off"-state. Moreover, the molecular weight cutoff of such membrane could be reversibly shifted from ∼70 to 1750 kDa by switching off or on the external AMF, as demonstrated in dextran ultrafiltration tests. Overall, it has been proved that the molecular sieving performance of the novel mixed matrix composite membrane can be controlled by the swollen/shrunken state of PNIPAAm NG embedded in the nanoporous barrier layer of a PES-based anisotropic porous matrix, via the heat generation of nearby MNP. And the structure of such membrane can be tailored by the NIPS process conditions. Such membrane has potential as enabling material for remote-controlled drug release systems or devices for

  6. Prediction of a Large-Gap and Switchable Kane-Mele Quantum Spin Hall Insulator

    Science.gov (United States)

    Marrazzo, Antimo; Gibertini, Marco; Campi, Davide; Mounet, Nicolas; Marzari, Nicola

    2018-03-01

    Fundamental research and technological applications of topological insulators are hindered by the rarity of materials exhibiting a robust topologically nontrivial phase, especially in two dimensions. Here, by means of extensive first-principles calculations, we propose a novel quantum spin Hall insulator with a sizable band gap of ˜0.5 eV that is a monolayer of jacutingaite, a naturally occurring layered mineral first discovered in 2008 in Brazil and recently synthesized. This system realizes the paradigmatic Kane-Mele model for quantum spin Hall insulators in a potentially exfoliable two-dimensional monolayer, with helical edge states that are robust and that can be manipulated exploiting a unique strong interplay between spin-orbit coupling, crystal-symmetry breaking, and dielectric response.

  7. Ultrastrong, Stiff and Multifunctional Carbon Nanotube Composites

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xin [North Carolina State University; Yong, Zhenzhong [Suzhou Institute of Nano-Tech and Nano-Bionics; Li, Qingwen [Suzhou Institute of Nano-Tech and Nano-Bionics; Bradford, Philip D. [North Carolina State University; Liu, Wei [Donghua University, Shanghai, China; Tucker, Dennis S. [Tucker Technical Solutions; Cai, Wei [ORNL; Wang, Hsin [ORNL; Yuan, Fuh-Gwo [North Carolina State University; Zhu, Yuntian [North Carolina State University

    2012-01-01

    Carbon nanotubes (CNTs) are an order of magnitude stronger than any current engineering fiber. However, for the past two decades it has been a challenge to utilize their reinforcement potential in composites. Here we report CNT composites with unprecedented multifunctionalities, including record high strength (3.8 GPa), Young s modulus (293 GPa), electrical conductivity (1230 S cm-1) and thermal conductivity (41 W m-1 K-1). These superior properties are derived from the long length, high volume fraction, good alignment and reduced waviness of the CNTs, which were produced by a novel processing approach that can be easily scaled up for industrial production.

  8. Hexagonal boron nitride and graphene in-plane heterostructures: An experimentally feasible approach to charge-induced switchable CO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Xin; Tahini, Hassan A.; Smith, Sean C., E-mail: sean.smith@unsw.edu.au

    2016-10-20

    Hexagonal boron nitride (h-BN) has been proposed as a sorbent material for charge-induced switchable CO{sub 2} capture. However, h-BN is a wide-gap semiconductor, hindering injection of the requisite charge. Here, we employ first-principle calculations to support the proposal that in-plane h-BN/graphene (P-BN/G) heterostructures, consisting of alternating strips of h-BN and graphene, may provide an experimentally feasible material platform for voltage-induced charging of h-BN strips to realize switchable CO{sub 2} capture. Our results show that a significant amount of injected negative charges are distributed onto h-BN strips of P-BN/G, such that CO{sub 2} capture/release can be simply controlled by switching on/off the charge states of P-BN/G system. At saturation CO{sub 2} capture coverage, the negatively charged P-BN/G heterostructures achieve CO{sub 2} capture capacities up to 2.27 × 10{sup 14} cm{sup −2}, which is twice that which can be achieved on stacked h-BN/graphene (S-BN/G) nanosheets.

  9. Tunable and switchable dual-wavelength single polarization narrow linewidth SLM erbium-doped fiber laser based on a PM-CMFBG filter.

    Science.gov (United States)

    Yin, Bin; Feng, Suchun; Liu, Zhibo; Bai, Yunlong; Jian, Shuisheng

    2014-09-22

    A tunable and switchable dual-wavelength single polarization narrow linewidth single-longitudinal-mode (SLM) erbium-doped fiber (EDF) ring laser based on polarization-maintaining chirped moiré fiber Bragg grating (PM-CMFBG) filter is proposed and demonstrated. For the first time as we know, the CMFBG inscribed on the PM fiber is applied for the wavelength-tunable and-switchable dual-wavelength laser. The PM-CMFBG filter with ultra-narrow transmission band (0.1 pm) and a uniform polarization-maintaining fiber Bragg grating (PM-FBG) are used to select the laser longitudinal mode. The stable single polarization SLM operation is guaranteed by the PM-CMFBG filter and polarization controller. A tuning range of about 0.25 nm with about 0.075 nm step is achieved by stretching the uniform PM-FBG. Meanwhile, the linewidth of the fiber laser for each wavelength is approximate 6.5 and 7.1 kHz with a 20 dB linewidth, which indicates the laser linewidth is approximate 325 Hz and 355 Hz FWHM.

  10. Electrically tunable superconducting terahertz metamaterial with low insertion loss and high switchable ratios

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chun; Zhang, Caihong, E-mail: chzhang@nju.edu.cn; Hu, Guoliang; Zhou, Gaochao; Jiang, Shoulu; Jiang, Chengtao; Zhu, Guanghao; Jin, Biaobing, E-mail: bbjin@nju.edu.cn; Kang, Lin; Xu, Weiwei; Chen, Jian; Wu, Peiheng [Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China)

    2016-07-11

    With the emergence and development of artificially structured electromagnetic materials, active terahertz (THz) metamaterial devices have attracted significant attention in recent years. Tunability of transmission is desirable for many applications. For example, short-range wireless THz communications and ultrafast THz interconnects require switches and modulators. However, the tunable range of transmission amplitude of existing THz metamaterial devices is not satisfactory. In this article, we experimentally demonstrate an electrically tunable superconducting niobium nitride metamaterial device and employ a hybrid coupling model to analyze its optical transmission characteristics. The maximum transmission coefficient at 0.507 THz is 0.98 and decreases to 0.19 when the applied voltage increases to 0.9 V. A relative transmittance change of 80.6% is observed, making this device an efficient narrowband THz switch. Additionally, the frequency of the peak is red shifted from 0.507 to 0.425 THz, which means that the device can be used to select the frequency. This study offers an alternative tuning method to existing optical, thermal, magnetic-field, and electric-field tuning, delivering a promising approach for designing active and miniaturized THz devices.

  11. Coupled Leidenfrost states as a monodisperse granular clock

    Science.gov (United States)

    Liu, Rui; Yang, Mingcheng; Chen, Ke; Hou, Meiying; To, Kiwing

    2016-08-01

    Using an event-driven molecular dynamics simulation, we show that simple monodisperse granular beads confined in coupled columns may oscillate as a different type of granular clock. To trigger this oscillation, the system needs to be driven against gravity into a density-inverted state, with a high-density clustering phase supported from below by a gaslike low-density phase (Leidenfrost effect) in each column. Our analysis reveals that the density-inverted structure and the relaxation dynamics between the phases can amplify any small asymmetry between the columns, and lead to a giant oscillation. The oscillation occurs only for an intermediate range of the coupling strength, and the corresponding phase diagram can be universally described with a characteristic height of the density-inverted structure. A minimal two-phase model is proposed and a linear stability analysis shows that the triggering mechanism of the oscillation can be explained as a switchable two-parameter Andronov-Hopf bifurcation. Numerical solutions of the model also reproduce similar oscillatory dynamics to the simulation results.

  12. Switchable insulation for using solar energy in buildings. Final report; Schaltbare Waermedaemmung (SWD) zur Nutzung der Sonnenenergie in Gebaeuden. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Stark, C.; Horn, R.; Hetfleisch, J.; Fricke, J.

    2003-02-25

    Solar energy can be used in buildings via use of transparent insulations. But thereby problems occur, like overheating of building walls in summer and heat losses in the cold season. To solve these problems ZAE Bayern has designed and optimized the switchable insulation SWD, the thermal conductivity of which can be changed from highly insulating to conducting. A computer routine was developed to calculate and to optimize the heat gains. The SWD is switched by desorbing/adsorbing as small amount of hydrogen gas. Desorption is facilitated with an electric heating element. The thermal conductivity of the filling can be varied by about a factor of 40. Several SWD-modules were produced and installed in an outside measuring facility. The heat gains and the durability were investigated for three years. The results of the simulation could be verified and ageing did not occur. For an optimal system the heat gains are in the range of 150 kWh/(m{sup 2}a). The mounting of these panels at south facades is simple, especially for post bolt systems. Contrary to transparent systems the loss of heat in winter is very small and the overheating of the walls behind the SWD in summer can be avoided. (orig.) [German] Zur Nutzung der Sonnenenergie in Gebaeuden werden bisher transparente Waermedaemmsysteme eingebaut, die jedoch oft mit Problemen wie Wandueberhitzung im Sommer und Waermeverlusten in der kalten Jahreszeit behaftet sind. Zur Loesung dieser Probleme wurde am ZAE Bayern eine schaltbare Waermedaemmung entwickelt und optimiert, deren Daemmeigenschaft je nach Sonneneinstrahlung und Waermebedarf variiert werden kann. Es wurde ein Programm entwickelt, mit dem die Waermegewinne berechnet und optimiert werden koennen. Die Schaltbarkeit wird durch einen Getter ermoeglicht, der eine ungefaehrliche Menge Wasserstoffgas reversibel aufnehmen und abgeben kann. Die Wasserstoff-Austreibung erfolgt mittels elektrischer Heizung und veraendert die Waermeleitfaehigkeit der Fuellung um einen

  13. Three-Way-Switchable (Right/Left/OFF) Selective Reflection of Circularly Polarized Light on Solid Thin Films of Helical Polymer Blends.

    Science.gov (United States)

    Nagata, Yuuya; Uno, Makoto; Suginome, Michinori

    2016-06-13

    Two poly(quinoxaline-2,3-diyl) copolymers bearing miscibility-enhancing 8-chlorooctyloxy and (S)-2-methylbutoxy or n-butoxy side chains were synthesized. After annealing in CHCl3 vapor, a polymer-blend film of these copolymers exhibited selective reflection of right-handed circularly polarized light (CPL) in the visible region. The handedness of the CPL reflected was completely inverted upon annealing of the film in THF vapor. Annealing in n-hexane vapor resulted in the phase separation of the polymer blend, which turned the selective reflection off. This three-way-switchable reflection, that is, reflection of right-handed or left-handed CPL, together with an OFF state, could be observed visually through right- and left-handed CPL filters. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Dark coupling

    International Nuclear Information System (INIS)

    Gavela, M.B.; Hernández, D.; Honorez, L. Lopez; Mena, O.; Rigolin, S.

    2009-01-01

    The two dark sectors of the universe—dark matter and dark energy—may interact with each other. Background and linear density perturbation evolution equations are developed for a generic coupling. We then establish the general conditions necessary to obtain models free from non-adiabatic instabilities. As an application, we consider a viable universe in which the interaction strength is proportional to the dark energy density. The scenario does not exhibit ''phantom crossing'' and is free from instabilities, including early ones. A sizeable interaction strength is compatible with combined WMAP, HST, SN, LSS and H(z) data. Neutrino mass and/or cosmic curvature are allowed to be larger than in non-interacting models. Our analysis sheds light as well on unstable scenarios previously proposed

  15. Reversible conversion of valence-tautomeric copper metal-organic frameworks dependent single-crystal-to-single-crystal oxidation/reduction: a redox-switchable catalyst for C-H bonds activation reaction.

    Science.gov (United States)

    Huang, Chao; Wu, Jie; Song, Chuanjun; Ding, Ran; Qiao, Yan; Hou, Hongwei; Chang, Junbiao; Fan, Yaoting

    2015-06-28

    Upon single-crystal-to-single-crystal (SCSC) oxidation/reduction, reversible structural transformations take place between the anionic porous zeolite-like Cu(I) framework and a topologically equivalent neutral Cu(I)Cu(II) mixed-valent framework. The unique conversion behavior of the Cu(I) framework endowed it as a redox-switchable catalyst for the direct arylation of heterocycle C-H bonds.

  16. An effervescence-assisted switchable fatty acid-based microextraction with solidification of floating organic droplet for determination of fluoroquinolones and tetracyclines in seawater, sediment, and seafood.

    Science.gov (United States)

    Gao, Ming; Wang, Jun; Song, Xiukai; He, Xin; Dahlgren, Randy A; Zhang, Zhenzhong; Ru, Shaoguo; Wang, Xuedong

    2018-04-01

    This study developed a new effervescence-assisted switchable fatty acid-based microextraction combined with solidification of a floating organic-droplet (EA-SFAM-SFO) for simple and rapid determination of fluoroquinolones and tetracyclines in seawater, sediment, and seafood. Five medium-chain fatty acids (pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, and nonanoic acid) were tested as an extraction solvent, given their ability to change between hydrophobic and hydrophilic forms by pH adjustment. As nonanoic acid had the highest extraction recovery (>92%) for the six antibiotics and the ability to transform from liquid to a solidified floating state at low temperature, it was selected as the optimum extraction solvent. The prominent advantages of the newly developed method are: (1) reaction between the procedures salt and fatty acid changed extraction solvent from the hydrophobic to hydrophilic state; (2) bubbling with CO 2 greatly increased the contact area between fatty acid and analytes resulting in improved extraction recovery; and (3) solidification of the fatty acid at a low temperature provided good separation and avoided the use of specialized equipment. Single-factor screening and optimization of the main factors were conducted using Plackett-Burman design and central composite design, respectively. The main parameters were optimized as follows: 258 μL fatty acid, 406 μL H 2 SO 4 (98%), 3.9 min vortex time, and 354 μL Na 2 CO 3 (2 mol L - 1). Under optimized conditions, limits of detection were 0.007-0.113 μg L -1 or μg kg -1 and extraction recoveries were 82.2%-116.7% for six fluoroquinolone and tetracycline antibiotics in seawater, sediments, and seafood. The newly developed method combines the advantages of effervescence-assisted dispersion, hydrophobic/hydrophilic switchable solvent, and liquid/solid transition induced by low temperature. Overall, the new method is simple, quick, and environment-friendly with low detection limits and

  17. Self-assembly of block copolymers into sieve-like particles with arrayed switchable channels and as scaffolds to guide the arrangement of gold nanoparticles.

    Science.gov (United States)

    He, Yun; Zhang, Yan; Yan, Nan; Zhu, Yutian; Jiang, Wei; Shi, Dean

    2017-10-12

    Well-defined polymeric particles with not only a controllable shape and internal nanostructures but also stimuli-responsive functions have attracted intensive attention because of their great potential in various fields. Herein, we created unique sieve-like particles with lattice arrayed switchable channels via the confined self-assembly of poly(4-vinylpyridine)-b-polystyrene-b-poly(4-vinylpyridine) (P4VP-b-PS-b-P4VP) triblock copolymers within the emulsion droplets and the subsequent swelling treatment in ethanol. It is worth noting that the hexagonally packed P4VP channels in the sieve-like particles are switched on and off by changing the solvent type, i.e., P4VP channels are switched on in ethanol and switched off in water, which can operate as a solvent-controlled chemical gate. Moreover, the well-defined sieve-like particles can be further used as scaffolds to guide the spatial arrangement of gold nanoparticles, which generates hybrid nanomaterials with controllable morphology and ordered spatial arrangement of AuNPs.

  18. 1.8 Å bright-state structure of the reversibly switchable fluorescent protein Dronpa guides the generation of fast switching variants

    Science.gov (United States)

    Stiel, Andre C.; Trowitzsch, Simon; Weber, Gert; Andresen, Martin; Eggeling, Christian; Hell, Stefan W.; Jakobs, Stefan; Wahl, Markus C.

    2006-01-01

    RSFPs (reversibly switchable fluorescent proteins) may be repeatedly converted between a fluorescent and a non-fluorescent state by irradiation and have attracted widespread interest for many new applications. The RSFP Dronpa may be switched with blue light from a fluorescent state into a non-fluorescent state, and back again with UV light. To obtain insight into the underlying molecular mechanism of this switching, we have determined the crystal structure of the fluorescent equilibrium state of Dronpa. Its bicyclic chromophore is formed spontaneously from the Cys62–Tyr63–Gly64 tripeptide. In the fluorescent state, it adopts a slightly non-coplanar cis conformation within the interior of a typical GFP (green fluorescent protein) β-can fold. Dronpa shares some structural features with asFP595, another RSFP whose chromophore has previously been demonstrated to undergo a cis–trans isomerization upon photoswitching. Based on the structural comparison with asFP595, we have generated new Dronpa variants with an up to more than 1000-fold accelerated switching behaviour. The mutations which were introduced at position Val157 or Met159 apparently reduce the steric hindrance for a cis–trans isomerization of the chromophore, thus lowering the energy barrier for the blue light-driven on-to-off transition. The findings reported in the present study support the view that a cis–trans isomerization is one of the key events common to the switching mechanism in RSFPs. PMID:17117927

  19. 1.8 A bright-state structure of the reversibly switchable fluorescent protein Dronpa guides the generation of fast switching variants.

    Science.gov (United States)

    Stiel, Andre C; Trowitzsch, Simon; Weber, Gert; Andresen, Martin; Eggeling, Christian; Hell, Stefan W; Jakobs, Stefan; Wahl, Markus C

    2007-02-15

    RSFPs (reversibly switchable fluorescent proteins) may be repeatedly converted between a fluorescent and a non-fluorescent state by irradiation and have attracted widespread interest for many new applications. The RSFP Dronpa may be switched with blue light from a fluorescent state into a non-fluorescent state, and back again with UV light. To obtain insight into the underlying molecular mechanism of this switching, we have determined the crystal structure of the fluorescent equilibrium state of Dronpa. Its bicyclic chromophore is formed spontaneously from the Cys62-Tyr63-Gly64 tripeptide. In the fluorescent state, it adopts a slightly non-coplanar cis conformation within the interior of a typical GFP (green fluorescent protein) b-can fold. Dronpa shares some structural features with asFP595, another RSFP whose chromophore has previously been demonstrated to undergo a cis-trans isomerization upon photoswitching. Based on the structural comparison with asFP595, we have generated new Dronpa variants with an up to more than 1000-fold accelerated switching behaviour. The mutations which were introduced at position Val157 or Met159 apparently reduce the steric hindrance for a cis-trans isomerization of the chromophore, thus lowering the energy barrier for the blue light-driven on-to-off transition. The findings reported in the present study support the view that a cis-trans isomerization is one of the key events common to the switching mechanism in RSFPs.

  20. "On-off" switchable tool for food sample preparation: merging molecularly imprinting technology with stimuli-responsive blocks. Current status, challenges and highlighted applications.

    Science.gov (United States)

    Garcia, Raquel; Gomes da Silva, Marco D R; Cabrita, Maria João

    2018-01-01

    Sample preparation still remains a great challenge in the analytical workflow representing the most time-consuming and laborious step in analytical procedures. Ideally, sample pre-treatment procedures must be more selective, cheap, quick and environmental friendly. Molecular imprinting technology is a powerful tool in the development of highly selective sample preparation methodologies enabling to preconcentrate the analytes from a complex food matrix. Actually, the design and development of molecularly imprinted polymers-based functional materials that merge an enhancement of selectivity with a controllable and switchable mode of action by means of specific stimulus constitutes a hot research topic in the field of food analysis. Thus, combining the stimuli responsive mechanism and imprinting technology a new generation of materials are emerging. The application of these smart materials in sample preparation is in early stage of development, nevertheless new improvements will promote a new driven in the demanding field of food sample preparation. The new trends in the advancement of food sample preparation using these smart materials will be presented in this review and highlighted the most relevant applications in this particular area of knowledge. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Path coupling and aggregate path coupling

    CERN Document Server

    Kovchegov, Yevgeniy

    2018-01-01

    This book describes and characterizes an extension to the classical path coupling method applied to statistical mechanical models, referred to as aggregate path coupling. In conjunction with large deviations estimates, the aggregate path coupling method is used to prove rapid mixing of Glauber dynamics for a large class of statistical mechanical models, including models that exhibit discontinuous phase transitions which have traditionally been more difficult to analyze rigorously. The book shows how the parameter regions for rapid mixing for several classes of statistical mechanical models are derived using the aggregate path coupling method.

  2. Switchable dual-wavelength single-longitudinal-mode erbium-doped fiber laser using an inverse-Gaussian apodized fiber Bragg grating filter and a low-gain semiconductor optical amplifier.

    Science.gov (United States)

    Lin, Bo; Tjin, Swee Chuan; Zhang, Han; Tang, Dingyuan; Hao, Jianzhong; Dong, Bo; Liang, Sheng

    2010-12-20

    We present a stable and switchable dual-wavelength erbium-doped fiber laser. In the ring cavity, an inverse-Gaussian apodized fiber Bragg grating serves as an ultranarrow dual-wavelength passband filter, a semiconductor optical amplifier biased in the low-gain regime reduces the gain competition of the two wavelengths, and a feedback fiber loop acts as a mode filter to guarantee a stable single-longitudinal-mode operation. Two lasing lines with a wavelength separation of approximately 0.1 nm are obtained experimentally. A microwave signal at 12.51 GHz is demonstrated by beating the dual wavelengths at a photodetector.

  3. Tailoring alphabetical metamaterials in optical frequency: plasmonic coupling, dispersion, and sensing.

    Science.gov (United States)

    Zhang, Jun; Cao, Cuong; Xu, Xinlong; Liow, Chihao; Li, Shuzhou; Tan, Pingheng; Xiong, Qihua

    2014-04-22

    Tailoring optical properties of artificial metamaterials, whose optical properties go beyond the limitations of conventional and naturally occurring materials, is of importance in fundamental research and has led to many important applications such as security imaging, invisible cloak, negative refraction, ultrasensitive sensing, and transformable and switchable optics. Herein, by precisely controlling the size, symmetry, and topology of alphabetical metamaterials with U, S, Y, H, U-bar, and V shapes, we have obtained highly tunable optical response covering visible-to-infrared (vis-NIR) optical frequency. In addition, we show a detailed study on the physical origin of resonance modes, plasmonic coupling, the dispersion of resonance modes, and the possibility of negative refraction. We have found that all the electronic and magnetic modes follow the dispersion of surface plasmon polaritons; thus, essentially they are electronic- and magnetic-surface-plasmon-polaritons-like (ESPP-like and MSPP-like) modes resulted from diffraction coupling between localized surface plasmon and freely propagating light. On the basis of the fill factor and formula of magnetism permeability, we predict that the alphabetical metamaterials should show the negative refraction capability in visible optical frequency. Furthermore, we have demonstrated the specific ultrasensitive surface enhanced Raman spectroscopy (SERS) sensing of monolayer molecules and femtomolar food contaminants by tuning their resonance to match the laser wavelength, or by tuning the laser wavelength to match the plasmon resonance of metamaterials. Our tunable alphabetical metamaterials provide a generic platform to study the electromagnetic properties of metamaterials and explore the novel applications in optical frequency.

  4. Extensively Reversible Thermal Transformations of a Bistable, Fluorescence-Switchable Molecular Solid: Entry into Functional Molecular Phase-Change Materials.

    Science.gov (United States)

    Srujana, P; Radhakrishnan, T P

    2015-06-15

    Functional phase-change materials (PCMs) are conspicuously absent among molecular materials in which the various attributes of inorganic solids have been realized. While organic PCMs are primarily limited to thermal storage systems, the amorphous-crystalline transformation of materials like Ge-Sb-Te find use in advanced applications such as information storage. Reversible amorphous-crystalline transformations in molecular solids require a subtle balance between robust supramolecular assembly and flexible structural elements. We report novel diaminodicyanoquinodimethanes that achieve this transformation by interlinked helical assemblies coupled with conformationally flexible alkoxyalkyl chains. They exhibit highly reversible thermal transformations between bistable (crystalline/amorphous) forms, along with a prominent switching of the fluorescence emission energy and intensity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Electromagnetic clutches and couplings

    CERN Document Server

    Vorob'Yeva, T M; Fry, D W; Higinbotham, W

    2013-01-01

    Electromagnetic Clutches and Couplings contains a detailed description of U.S.S.R. electromagnetic friction clutches, magnetic couplings, and magnetic particle couplings. This book is divided into four chapters. The first chapter discusses the design and construction of magnetic (solenoid-operated) couplings, which are very quick-acting devices and used in low power high-speed servo-systems. Chapter 2 describes the possible fields of application, design, construction, and utilization of magnetic particle couplings. The aspects of construction, design, and utilization of induction clutches (sli

  6. Observation of Switchable Photoresponse of a Monolayer WSe 2 –MoS 2 Lateral Heterostructure via Photocurrent Spectral Atomic Force Microscopic Imaging

    KAUST Repository

    Son, Youngwoo

    2016-04-27

    In the pursuit of two-dimensional (2D) materials beyond graphene, enormous advances have been made in exploring the exciting and useful properties of transition metal dichalcogenides (TMDCs), such as a permanent band gap in the visible range and the transition from indirect to direct band gap due to 2D quantum confinement, and their potential for a wide range of device applications. In particular, recent success in the synthesis of seamless monolayer lateral heterostructures of different TMDCs via chemical vapor deposition methods has provided an effective solution to producing an in-plane p-n junction, which is a critical component in electronic and optoelectronic device applications. However, spatial variation of the electronic and optoelectonic properties of the synthesized heterojunction crystals throughout the homogeneous as well as the lateral junction region and the charge carrier transport behavior at their nanoscale junctions with metals remain unaddressed. In this work, we use photocurrent spectral atomic force microscopy to image the current and photocurrent generated between a biased PtIr tip and a monolayer WSe2-MoS2 lateral heterostructure. Current measurements in the dark in both forward and reverse bias reveal an opposite characteristic diode behavior for WSe2 and MoS2, owing to the formation of a Schottky barrier of dissimilar properties. Notably, by changing the polarity and magnitude of the tip voltage applied, pixels that show the photoresponse of the heterostructure are observed to be selectively switched on and off, allowing for the realization of a hyper-resolution array of the switchable photodiode pixels. This experimental approach has significant implications toward the development of novel optoelectronic technologies for regioselective photodetection and imaging at nanoscale resolutions. Comparative 2D Fourier analysis of physical height and current images shows high spatial frequency variations in substrate/MoS2 (or WSe2) contact that

  7. Oligo-m-phenyleneoxalamide copper(II) mesocates as electro-switchable ferromagnetic metal-organic wires.

    Science.gov (United States)

    Pardo, Emilio; Ferrando-Soria, Jesús; Dul, Marie-Claire; Lescouëzec, Rodrigue; Journaux, Yves; Ruiz-García, Rafael; Cano, Joan; Julve, Miguel; Lloret, Francesc; Cañadillas-Delgado, Laura; Pasán, Jorge; Ruiz-Pérez, Catalina

    2010-11-15

    Double-stranded copper(II) string complexes of varying nuclearity, from di- to tetranuclear species, have been prepared by the Cu(II)-mediated self-assembly of a novel family of linear homo- and heteropolytopic ligands that contain two outer oxamato and either zero (1 b), one (2 b), or two (3 b) inner oxamidato donor groups separated by rigid 2-methyl-1,3-phenylene spacers. The X-ray crystal structures of these Cu(II) (n) complexes (n=2 (1 d), 3 (2 d), and 4 (3 d)) show a linear array of metal atoms with an overall twisted coordination geometry for both the outer CuN(2)O(2) and inner CuN(4) chromophores. Two such nonplanar all-syn bridging ligands 1 b-3 b in an anti arrangement clamp around the metal centers with alternating M and P helical chiralities to afford an overall double meso-helicate-type architecture for 1 d-3 d. Variable-temperature (2.0-300 K) magnetic susceptibility and variable-field (0-5.0 T) magnetization measurements for 1 d-3 d show the occurrence of S=nS(Cu) (n=2-4) high-spin ground states that arise from the moderate ferromagnetic coupling between the unpaired electrons of the linearly disposed Cu(II) ions (S(Cu)=1/2) through the two anti m-phenylenediamidate-type bridges (J values in the range of +15.0 to 16.8 cm(-1)). Density functional theory (DFT) calculations for 1 d-3 d evidence a sign alternation of the spin density in the meta-substituted phenylene spacers in agreement with a spin polarization exchange mechanism along the linear metal array with overall intermetallic distances between terminal metal centers in the range of 0.7-2.2 nm. Cyclic voltammetry (CV) and rotating-disk electrode (RDE) electrochemical measurements for 1 d-3 d show several reversible or quasireversible one- or two-electron steps that involve the consecutive metal-centered oxidation of the inner and outer Cu(II) ions (S(Cu)=1/2) to diamagnetic Cu(III) ones (S(Cu)=0) at relatively low formal potentials (E values in the range of

  8. Conformally Coupled Inflation

    Directory of Open Access Journals (Sweden)

    Valerio Faraoni

    2013-07-01

    Full Text Available A massive scalar field in a curved spacetime can propagate along the light cone, a causal pathology, which can, in principle, be eliminated only if the scalar couples conformally to the Ricci curvature of spacetime. This property mandates conformal coupling for the field driving inflation in the early universe. During slow-roll inflation, this coupling can cause super-acceleration and, as a signature, a blue spectrum of primordial gravitational waves.

  9. Integrative Behavioral Couple Therapy

    OpenAIRE

    Christensen, Andrew; Doss, Brian D.

    2017-01-01

    Integrative Behavioral Couple Therapy (IBCT) is based in part on traditional behavioral couple therapy but expands both the conceptualization of couple distress and of intervention. The efficacy of IBCT has been supported in three clinical trials, including one with five year follow-up. Additionally, the effectiveness of IBCT in the real world has been supported through a system-wide dissemination effort in the United States Department of Veteran’s Affairs. The reach of IBCT has also been ext...

  10. Conversation, coupling and complexity

    DEFF Research Database (Denmark)

    Fusaroli, Riccardo; Abney, Drew; Bahrami, Bahador

    We investigate the linguistic co-construction of interpersonal synergies. By applying a measure of coupling between complex systems to an experimentally elicited corpus of joint decision dialogues, we show that interlocutors’ linguistic behavior displays increasing signature of multi-scale coupling......, known as complexity matching, over the course of interaction. Furthermore, we show that stronger coupling corresponds with more effective interaction, as measured by collective task performance....

  11. Translation-coupling systems

    Science.gov (United States)

    Pfleger, Brian; Mendez-Perez, Daniel

    2013-11-05

    Disclosed are systems and methods for coupling translation of a target gene to a detectable response gene. A version of the invention includes a translation-coupling cassette. The translation-coupling cassette includes a target gene, a response gene, a response-gene translation control element, and a secondary structure-forming sequence that reversibly forms a secondary structure masking the response-gene translation control element. Masking of the response-gene translation control element inhibits translation of the response gene. Full translation of the target gene results in unfolding of the secondary structure and consequent translation of the response gene. Translation of the target gene is determined by detecting presence of the response-gene protein product. The invention further includes RNA transcripts of the translation-coupling cassettes, vectors comprising the translation-coupling cassettes, hosts comprising the translation-coupling cassettes, methods of using the translation-coupling cassettes, and gene products produced with the translation-coupling cassettes.

  12. Coupling in the Tevatron

    International Nuclear Information System (INIS)

    Gelfand, N.M.

    1994-12-01

    The performance of the Fermilab Tevatron Collider at the commencement of run Ib was far below expectations. After a frustrating period of several months, a low-β quad downstream of the interaction point at B0 was found to be rolled. This rolled quadrupole coupled the horizontal and vertical motion of the Tevatron beams. It also made matching the beam from the Main Ring to the Tevatron impossible, resulting in emittance blow up on injection. The net result of the roll was a significant reduction in the Tevatron luminosity. When the roll in the quadrupole was corrected the performance of the Tevatron improved dramatically. This note will discuss the experimental data indicating the presence of coupling and subsequent calculations which show how coupling an affect the luminosity. It is not intended to exhaust a discussion of coupling, which hopefully will be understood well enough to be discussed in a subsequent note

  13. Coupling in the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Gelfand, N.M.

    1994-12-01

    The performance of the Fermilab Tevatron Collider at the commencement of run Ib was far below expectations. After a frustrating period of several months, a low-{beta} quad downstream of the interaction point at B0 was found to be rolled. This rolled quadrupole coupled the horizontal and vertical motion of the Tevatron beams. It also made matching the beam from the Main Ring to the Tevatron impossible, resulting in emittance blow up on injection. The net result of the roll was a significant reduction in the Tevatron luminosity. When the roll in the quadrupole was corrected the performance of the Tevatron improved dramatically. This note will discuss the experimental data indicating the presence of coupling and subsequent calculations which show how coupling an affect the luminosity. It is not intended to exhaust a discussion of coupling, which hopefully will be understood well enough to be discussed in a subsequent note.

  14. Triple gauge boson couplings

    CERN Document Server

    Gounaris, George J; Zeppenfeld, Dieter; Ajaltouni, Ziad J; Arhrib, A; Bella, G; Berends, F A; Bilenky, S M; Blondel, A; Busenitz, J K; Choudhury, D; Clarke, P; Conboy, J E; Diehl, M; Fassouliotis, D; Frère, J M; Georgiopoulos, C H; Gibbs, M; Grünewald, M W; Hansen, J B; Hartmann, C; Jin, B N; Jousset, J; Kalinowski, Jan; Kocian, M L; Lahanas, Athanasios B; Layssac, J; Lieb, E H; Markou, C; Matteuzzi, C; Mättig, P; Moreno, J M; Moultaka, G; Nippe, A; Orloff, J; Papadopoulos, C G; Paschalis, J; Petridou, C; Phillips, H; Podlyski, F; Pohl, M; Renard, F M; Rossignol, J M; Rylko, R; Sekulin, R L; Van Sighem, A; Simopoulou, Errietta; Skillman, A; Spanos, V C; Tonazzo, A; Tytgat, M H G; Tzamarias, S; Verzegnassi, Claudio; Vlachos, N D; Zevgolatakos, E

    1996-01-01

    We present the results obtained by the "Triple Gauge Couplings" working group during the LEP2 Workshop (1994-1995). The report concentrates on the measurement of WW\\gamma and WWZ couplings in e^-e^+\\to W^-W^+ or, more generally, four-fermion production at LEP2. In addition the detection of new interactions in the bosonic sector via other production channels is discussed.

  15. Pion coupling to nuclei

    International Nuclear Information System (INIS)

    Dumbrajs, O.

    1981-01-01

    The concept of the pion-nucleus coupling constants is discussed. Methods of their determination are reviewed. These include: forward dispersion relations, extrapolation of differential cross sections to the poles in the angular variable, analysis of data on electromagnetic form factors with the use of the PCAC and CVC hypotheses, pion photoproduction at threshold and low-energy theorems. Our present knowledge of the pion coupling to the He, Li, Be, C, N and O nuclei is summarized. (author)

  16. Switchable Materials for Smart Windows.

    Science.gov (United States)

    Wang, Yang; Runnerstrom, Evan L; Milliron, Delia J

    2016-06-07

    This article reviews the basic principles of and recent developments in electrochromic, photochromic, and thermochromic materials for applications in smart windows. Compared with current static windows, smart windows can dynamically modulate the transmittance of solar irradiation based on weather conditions and personal preferences, thus simultaneously improving building energy efficiency and indoor human comfort. Although some smart windows are commercially available, their widespread implementation has not yet been realized. Recent advances in nanostructured materials provide new opportunities for next-generation smart window technology owing to their unique structure-property relations. Nanomaterials can provide enhanced coloration efficiency, faster switching kinetics, and longer lifetime. In addition, their compatibility with solution processing enables low-cost and high-throughput fabrication. This review also discusses the importance of dual-band modulation of visible and near-infrared (NIR) light, as nearly 50% of solar energy lies in the NIR region. Some latest results show that solution-processable nanostructured systems can selectively modulate the NIR light without affecting the visible transmittance, thus reducing energy consumption by air conditioning, heating, and artificial lighting.

  17. Projected coupled cluster theory.

    Science.gov (United States)

    Qiu, Yiheng; Henderson, Thomas M; Zhao, Jinmo; Scuseria, Gustavo E

    2017-08-14

    Coupled cluster theory is the method of choice for weakly correlated systems. But in the strongly correlated regime, it faces a symmetry dilemma, where it either completely fails to describe the system or has to artificially break certain symmetries. On the other hand, projected Hartree-Fock theory captures the essential physics of many kinds of strong correlations via symmetry breaking and restoration. In this work, we combine and try to retain the merits of these two methods by applying symmetry projection to broken symmetry coupled cluster wave functions. The non-orthogonal nature of states resulting from the application of symmetry projection operators furnishes particle-hole excitations to all orders, thus creating an obstacle for the exact evaluation of overlaps. Here we provide a solution via a disentanglement framework theory that can be approximated rigorously and systematically. Results of projected coupled cluster theory are presented for molecules and the Hubbard model, showing that spin projection significantly improves unrestricted coupled cluster theory while restoring good quantum numbers. The energy of projected coupled cluster theory reduces to the unprojected one in the thermodynamic limit, albeit at a much slower rate than projected Hartree-Fock.

  18. Cognitive coupling during reading.

    Science.gov (United States)

    Mills, Caitlin; Graesser, Art; Risko, Evan F; D'Mello, Sidney K

    2017-06-01

    We hypothesize that cognitively engaged readers dynamically adjust their reading times with respect to text complexity (i.e., reading times should increase for difficult sections and decrease for easier ones) and failure to do so should impair comprehension. This hypothesis is consistent with theories of text comprehension but has surprisingly been untested. We tested this hypothesis by analyzing 4 datasets in which participants (N = 484) read expository texts using a self-paced reading paradigm. Participants self-reported mind wandering in response to pseudorandom thought-probes during reading and completed comprehension assessments after reading. We computed two measures of cognitive coupling by regressing each participant's paragraph-level reading times on two measures of text complexity: Flesch-Kincaid Grade Level and Word Concreteness scores. The two coupling measures yielded convergent findings: coupling was a negative predictor of mind wandering and a positive predictor of both text- and inference-level comprehension. Goodness-of-fit, measured with Akaike information criterion, also improved after adding coupling to the reading-time only models. Furthermore, cognitive coupling mediated the relationship between mind wandering and comprehension, supporting the hypothesis that mind wandering engenders a decoupling of attention from external stimuli. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  19. Integrative Behavioral Couple Therapy.

    Science.gov (United States)

    Christensen, Andrew; Doss, Brian D

    2017-02-01

    Integrative Behavioral Couple Therapy (IBCT) is based in part on traditional behavioral couple therapy but expands both the conceptualization of couple distress and of intervention. The efficacy of IBCT has been supported in three clinical trials, including one with five year follow-up. Additionally, the effectiveness of IBCT in the real world has been supported through a system-wide dissemination effort in the United States Department of Veteran's Affairs. The reach of IBCT has also been extended through an online program, www.OurRelationship.com, based on IBCT. A nationwide clinical trial with a representative sample of the US population demonstrated the effectiveness of this program on both relationship and individual variables.

  20. Structural Coupling and Translation

    DEFF Research Database (Denmark)

    Tække, Jesper

    of structural couplings between psychic and social systems (Luhmann 2002: 275, Tække 2011). In this way media are seen as a necessary third, making it possible for two different kinds of systems to process, using complexity from one another - leaving out the idea of direct transmission. In actor-network theory...... Danish to English, but to describe: “displacement, drift, invention, mediation, the creation of a link that did not exist before and that to some degree modifies two elements or agents” (Latour 1994, 32). The paper works with two aims. The first aim is to discuss what kinds of structural couplings...... to compare the semantics of their concepts. The paper first provides an analysis and discussion of language as the mechanism of structural coupling between the levels of psychic and social systems. Then the article provides an analysis and discussion of translation as a transformation process between actors...

  1. Coupled moderator neutronics

    International Nuclear Information System (INIS)

    Russell, G.J.; Pitcher, E.J.; Ferguson, P.D.

    1995-01-01

    Optimizing the neutronic performance of a coupled-moderator system for a Long-Pulse Spallation Source is a new and challenging area for the spallation target-system designer. For optimal performance of a neutron source, it is essential to have good communication with instrument scientists to obtain proper design criteria and continued interaction with mechanical, thermal-hydraulic, and materials engineers to attain a practical design. A good comprehension of the basics of coupled-moderator neutronics will aid in the proper design of a target system for a Long-Pulse Spallation Source

  2. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  3. International Migration of Couples

    DEFF Research Database (Denmark)

    Junge, Martin; Munk, Martin D.; Nikolka, Till

    2018-01-01

    Migrant self-selection is important to labor markets and public finances in both origin and destination countries. We develop a theoretical model regarding the migration of dual-earner couples and test it using population-wide administrative data from Denmark. Our model predicts that the probabil......Migrant self-selection is important to labor markets and public finances in both origin and destination countries. We develop a theoretical model regarding the migration of dual-earner couples and test it using population-wide administrative data from Denmark. Our model predicts...

  4. Coupling in reflector arrays

    DEFF Research Database (Denmark)

    Appel-Hansen, Jørgen

    1968-01-01

    In order to reduce the space occupied by a reflector array, it is desirable to arrange the array antennas as close to each other as possible; however, in this case coupling between the array antennas will reduce the reflecting properties of the reflector array. The purpose of the present communic......In order to reduce the space occupied by a reflector array, it is desirable to arrange the array antennas as close to each other as possible; however, in this case coupling between the array antennas will reduce the reflecting properties of the reflector array. The purpose of the present...

  5. ElectroWeak Bosons Couplings

    CERN Document Server

    Ouraou, Ahmimed; The ATLAS collaboration

    2016-01-01

    Latest results on the measurement of gauge boson couplings, from ATLAS and CMS at the LHC, are presented. This review starts with an introduction to boson couplings, then the measurements of Triple and Quartic Couplings are described. And finally, limits on anomalous couplings are summarized.

  6. Coupled superconductors and beyond

    International Nuclear Information System (INIS)

    Josephson, Brian D.

    2012-01-01

    This paper describes the events leading to the discovery of coupled superconductors, the author move in the 1970s to a perspective where mind plays a role comparable to matter, and the remarkable hostility sometimes encountered by those who venture into unconventional areas.

  7. Anomalous top magnetic couplings

    Indian Academy of Sciences (India)

    2012-11-09

    Nov 9, 2012 ... Corresponding author. E-mail: remartinezm@unal.edu.co. Abstract. The real and imaginary parts of the one-loop electroweak contributions to the left and right tensorial anomalous couplings of the tbW vertex in the Standard Model (SM) are computed. Keywords. Top; anomalous. PACS Nos 14.65.Ha; 12.15 ...

  8. Benefits for Gay Couples.

    Science.gov (United States)

    Collison, Michele N-K

    1993-01-01

    Increasingly, colleges are finding it hypocritical to have nondiscrimination policies protecting gay faculty and staff but deny benefits available to married employees. Institutions have adopted different criteria to determine who qualifies as a "spousal equivalent." The standards may face legal challenges from unmarried heterosexual couples. (MSE)

  9. Gravitationally coupled electroweak monopole

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Y.M., E-mail: ymcho7@konkuk.ac.kr [Administration Building 310-4, Konkuk University, Seoul 143-701 (Korea, Republic of); School of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Kimm, Kyoungtae [Faculty of Liberal Education, Seoul National University, Seoul 151-747 (Korea, Republic of); Yoon, J.H. [Department of Physics, College of Natural Sciences, Konkuk University, Seoul 143-701 (Korea, Republic of)

    2016-10-10

    We present a family of gravitationally coupled electroweak monopole solutions in Einstein–Weinberg–Salam theory. Our result confirms the existence of globally regular gravitating electroweak monopole which changes to the magnetically charged black hole as the Higgs vacuum value approaches to the Planck scale. Moreover, our solutions could provide a more accurate description of the monopole stars and magnetically charged black holes.

  10. HIV-discordant couples

    African Journals Online (AJOL)

    Winnie

    2006-06-02

    Jun 2, 2006 ... These may broadly be divided into factors that affect the transmissibility of HIV between couples per sex act and factors influencing the number of sex acts during which exposure may occur. Examples of the former include use of condoms or other barrier methods and certain sexual behaviours, such as sex.

  11. Warthog: Coupling Status Update

    Energy Technology Data Exchange (ETDEWEB)

    Hart, Shane W. D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Reardon, Bradley T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-30

    The Warthog code was developed to couple codes that are developed in both the Multi-Physics Object-Oriented Simulation Environment (MOOSE) from Idaho National Laboratory (INL) and SHARP from Argonne National Laboratory (ANL). The initial phase of this work, focused on coupling the neutronics code PROTEUS with the fuel performance code BISON. The main technical challenge involves mapping the power density solution determined by PROTEUS to the fuel in BISON. This presents a challenge since PROTEUS uses the MOAB mesh format, but BISON, like all other MOOSE codes, uses the libMesh format. When coupling the different codes, one must consider that Warthog is a light-weight MOOSE-based program that uses the Data Transfer Kit (DTK) to transfer data between the various mesh types. Users set up inputs for the codes they want to run, and then Warthog transfers the data between them. Currently Warthog supports XSProc from SCALE or the Sub-Group Application Programming Interface (SGAPI) in PROTEUS for generating cross sections. It supports arbitrary geometries using PROTEUS and BISON. DTK will transfer power densities and temperatures between the codes where the domains overlap. In the past fiscal year (FY), much work has gone into demonstrating two-way coupling for simple pin cells of various materials. XSProc was used to calculate the cross sections, which were then passed to PROTEUS in an external file. PROTEUS calculates the fission/power density, and Warthog uses DTK to pass this information to BISON, where it is used as the heat source. BISON then calculates the temperature profile of the pin cell and sends it back to XSProc to obtain the temperature corrected cross sections. This process is repeated until the convergence criteria (tolerance on BISON solve, or number of time steps) is reached. Models have been constructed and run for both uranium oxide and uranium silicide fuels. These models demonstrate a clear difference in power shape that is not accounted for in a

  12. Quick connect coupling

    Science.gov (United States)

    Lomax, Curtis; Webbon, Bruce

    1995-02-01

    A cooling apparatus includes a container filled with a quantity of coolant fluid initially cooled to a solid phase, a cooling loop disposed between a heat load and the container, a pump for circulating a quantity of the same type of coolant fluid in a liquid phase through the cooling loop, and a pair of couplings for communicating the liquid phase coolant fluid into the container in a direct interface with the solid phase coolant fluid.

  13. Controllable optomechanical coupling in serially-coupled triple resonators

    Directory of Open Access Journals (Sweden)

    Chenguang Huang

    2014-12-01

    Full Text Available Radiation pressure can efficiently couple mechanical modes with optical modes in an optical cavity. The coupling efficiency is quite dependent on the interaction between the optical mode and mechanical mode. In this report, we investigate a serially-coupled triple resonator system, where a freestanding beam is placed in the vicinity of the middle resonator. In this coupled system, we demonstrate that the mechanical mode of the free-standing beam can be selectively coupled to different resonance supermodes through the near field interaction.

  14. Two career couple

    Science.gov (United States)

    Sancetta, Constance

    1984-04-01

    Over 150 members of AGU attended a panel session on “The Two Career Couple: Balancing Personal and Professional Life” at the 1983 AGU Fall Meeting in San Francisco. The panel was sponsored by the Education and Human Resources Committee and was chaired by Constance Sancetta. On the panel were Alice Newman, of The Aerospace Corporation; Mark Zoback and Mary Lou Zoback of U.S. Geological Survey, Menlo Park; and Judith Moody of ONWI-Battelle and her husband, Thomas Worsley of Ohio University. The audience included many students but was composed primarily of professionals 30-40, with men and women equally represented.

  15. Loosely coupled class families

    DEFF Research Database (Denmark)

    Ernst, Erik

    2001-01-01

    are expressed using virtual classes seem to be very tightly coupled internally. While clients have achieved the freedom to dynamically use one or the other family, it seems that any given family contains a xed set of classes and we will need to create an entire family of its own just in order to replace one...... of the members with another class. This paper shows how to express class families in such a manner that the classes in these families can be used in many dierent combinations, still enabling family polymorphism and ensuring type safety....

  16. LIA longitudinal coupling impedance

    International Nuclear Information System (INIS)

    Faltens, A.

    1980-01-01

    The beam generated fields enter into the problems of waveform generation and longitudinal stability. In the former, provision must be made for the longitudinally defocusing forces due to the space charge and the beam loading effects on the accelerating voltage due to the current of a presumably known bunch. In the latter, the concern is for the growth of unintentional perturbations to unacceptably large values through the interaction of the charge and current fluctuations with the rest of the beam and the surrounding structures. These beam generated electric fields may be related to the beam current through a coupling impedance

  17. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  18. Magnetically Coupled Calorimeters

    Science.gov (United States)

    Bandler, Simon

    2011-01-01

    Calorimeters that utilize the temperature sensitivity of magnetism have been under development for over 20 years. They have targeted a variety of different applications that require very high resolution spectroscopy. I will describe the properties of this sensor technology that distinguish it from other low temperature detectors and emphasize the types of application to which they appear best suited. I will review what has been learned so far about the best materials, geometries, and read-out amplifiers and our understanding of the measured performance and theoretical limits. I will introduce some of the applications where magnetic calorimeters are being used and also where they are in development for future experiments. So far, most magnetic calorimeter research has concentrated on the use of paramagnets to provide temperature sensitivity; recent studies have also focused on magnetically coupled calorimeters that utilize the diamagnetic response of superconductors. I will present some of the highlights of this research, and contrast the properties of the two magnetically coupled calorimeter types.

  19. COUPLED CHEMOTAXIS FLUID MODEL

    KAUST Repository

    LORZ, ALEXANDER

    2010-06-01

    We consider a model system for the collective behavior of oxygen-driven swimming bacteria in an aquatic fluid. In certain parameter regimes, such suspensions of bacteria feature large-scale convection patterns as a result of the hydrodynamic interaction between bacteria. The presented model consist of a parabolicparabolic chemotaxis system for the oxygen concentration and the bacteria density coupled to an incompressible Stokes equation for the fluid driven by a gravitational force of the heavier bacteria. We show local existence of weak solutions in a bounded domain in d, d = 2, 3 with no-flux boundary condition and in 2 in the case of inhomogeneous Dirichlet conditions for the oxygen. © 2010 World Scientific Publishing Company.

  20. Gay and lesbian couples in Italy: comparisons with heterosexual couples.

    Science.gov (United States)

    Antonelli, Paolo; Dèttore, Davide; Lasagni, Irene; Snyder, Douglas K; Balderrama-Durbin, Christina

    2014-12-01

    Assessing couple relationships across diverse languages and cultures has important implications for both clinical intervention and prevention. This is especially true for nontraditional relationships potentially subject to various expressions of negative societal evaluation or bias. Few empirically validated measures of relationship functioning have been developed for cross-cultural applications, and none have been examined for their psychometric sufficiency for evaluating same-sex couples across different languages and cultures. The current study examined the psychometric properties of an Italian translation of the Marital Satisfaction Inventory - Revised (MSI-R), a 150-item 13-scale measure of couple relationship functioning, for its use in assessing the intimate relationships of gay and lesbian couples in Italy. Results for these couples were compared to data from heterosexual married and unmarried cohabiting couples from the same geographical region, as well as to previously published data for gay, lesbian, and unmarried heterosexual couples from the United States. Findings suggest that, despite unique societal pressures confronting Italian same-sex couples, these relationships appear resilient and fare well both overall and in specific domains of functioning compared to heterosexual couples both in Italy and the United States. © 2014 Family Process Institute.

  1. Synchronizability of coupled PWL maps

    International Nuclear Information System (INIS)

    Polynikis, A.; Di Bernardo, M.; Hogan, S.J.

    2009-01-01

    In this paper we discuss the phenomenon of synchronization of chaotic systems in the case of coupled piecewise linear (PWL) continuous and discontinuous one-dimensional maps. We present numerical results for two examples of coupled systems consisting of two PWL maps. We illustrate how the coupled system can achieve synchronization and discuss the nature of the bifurcation that occurs at a critical value of the coupling strength. We then determine this critical coupling using linear stability analysis. We discuss the effects of variation of the parameters of the PWL maps on the critical coupling and present different bifurcation scenarios obtained for different sets of values of these parameters. Finally, we discuss an extension of our work to the synchronizability of networks consisting of two or more PWL maps. We show how the synchronizability of a network of PWL maps can be improved by tuning the map parameters.

  2. ESPC Coupled Global Prediction System

    Science.gov (United States)

    2015-09-30

    through an improvement to the sea ice albedo . Fig. 3: 2-m Temperature bias (deg C) of 120-h forecasts for the month of May 2014 for the Arctic...forecast system (NAVGEM) and ocean- sea ice forecast system (HYCOM/CICE) have never been coupled at high resolution. The coupled processes will be...winds and currents across the interface. The sea - ice component of this project requires modification of CICE versions 4 and 5 to run in the coupled

  3. Performance assessment of coupled processes

    International Nuclear Information System (INIS)

    Pigford, T.H.

    1987-01-01

    The author considers all processes to be coupled. For example, a waste package heats the surrounding rock and its pore water, creating gradients in density and pressure that result in increased water flow. That process can be described as coupled, in that the flow is a consequence of heating. In a narrower sense, one speaks also of the more weakly coupled transport processes, expressed by the Onsager reciprocal relations, that state that a transport current, i.e., flux, of heat is accompanied by a small transport current of material, as evidenced in isotope separation by thermal diffusion, the Thompson effect in thermoelectricity, etc. This paper presents a performance assessment of coupled processes

  4. Cosmological tests of coupled Galileons

    International Nuclear Information System (INIS)

    Brax, Philippe; Burrage, Clare; Davis, Anne-Christine; Gubitosi, Giulia

    2015-01-01

    We investigate the cosmological properties of Galileon models which admit Minkowski space as a stable solution in vacuum. This is motivated by stable, positive tension brane world constructions that give rise to Galileons. We include both conformal and disformal couplings to matter and focus on constraints on the theory that arise because of these couplings. The disformal coupling to baryonic matter is extremely constrained by astrophysical and particle physics effects. The disformal coupling to photons induces a cosmological variation of the speed of light and therefore distorsions of the Cosmic Microwave Background spectrum which are known to be very small. The conformal coupling to baryons leads to a variation of particle masses since Big Bang Nucleosynthesis which is also tightly constrained. We consider the background cosmology of Galileon models coupled to Cold Dark Matter (CDM), photons and baryons and impose that the speed of light and particle masses respect the observational bounds on cosmological time scales. We find that requiring that the equation of state for the Galileon models must be close to -1 now restricts severely their parameter space and can only be achieved with a combination of the conformal and disformal couplings. This leads to large variations of particle masses and the speed of light which are not compatible with observations. As a result, we find that cosmological Galileon models are viable dark energy theories coupled to dark matter but their couplings, both disformal and conformal, to baryons and photons must be heavily suppressed making them only sensitive to CDM

  5. Coupled-resonator optical waveguides

    DEFF Research Database (Denmark)

    Raza, Søren; Grgic, Jure; Pedersen, Jesper Goor

    2010-01-01

    Coupled-resonator optical waveguides hold potential for slow-light propagation of optical pulses. The dispersion properties may adequately be analyzed within the framework of coupled-mode theory. We extend the standard coupled-mode theory for such structures to also include complex......-valued parameters which allows us to analyze the dispersion properties also in presence of finite Q factors for the coupled resonator states. Near the band-edge the group velocity saturates at a finite value vg/c µ p1/Q while in the band center, the group velocity is unaffected by a finite Q factor as compared...

  6. Coupled processes in geomechanics

    International Nuclear Information System (INIS)

    Cook, N.G.W.

    1987-01-01

    The safe operation of an underground repository for the disposal of nuclear wastes, and the isolation of these wastes form the accessible environment, may be affected adversely by the formation of new fractures in the rock close to these excavations or by movements across pre-existing fractures. Both phenomena may so enhance the permeability of the rock as to allow possibly contaminated groundwater to reach the accessible environment. For hard rocks, the formation of new fractures in the regions of high stress concentration adjacent to excavations is analyzed in terms of breakouts or spalling. In rocksalt, creep may allow the stress adjacent to excavations to decrease below the hydrostatic pressure so that hydraulic fractures may form, or the extension of layers other than salt may produce new hydraulic conduits. The deformation of fractures in response to changes in stress pore pressure and temperature are analyzed for pre-existing fractures, as is also the shear stability of the fractures. Experience and in situ testing are seen to be of the greatest importance in identifying and understanding coupled phenomenon in geomechanics

  7. Coupled processes in geomechanics

    International Nuclear Information System (INIS)

    Cook, N.G.W.

    1985-01-01

    The safe operation of an underground repository for the disposal of nuclear wastes and the isolation of these wastes from the accessible environment, may be affected adversely by the formation of new fractures in the rock close to these excavations or by movements across pre-existing fractures. Both phenomena may so enhance the permeability of the rock as to allow possibly contaminated groundwater to reach the accessible environment. For hard rocks, the formation of new fractures in the regions of high stress concentration adjacent to excavations is analyzed in terms of breakouts or spalling. In rocksalt, creep may allow the stress adjacent to excavations to decrease below the hydrostatic pressure so that hydraulic fractures may form, or the extension of layers other than salt may produce new hydraulic conduits. The deformation of fractures in response to changes in stress pore pressure, and temperature are analyzed for pre-existing fractures, as is also the shear stability of the fractures. Experience and in situ testing are seen to be of the greatest importance in identifying and understanding coupled phenomenon in geomechanics

  8. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  9. Belpex and trilateral market coupling

    International Nuclear Information System (INIS)

    2006-01-01

    This document describes the operation of Belpex, the Belgian power transmission spot market, and its linking with the French (Powernext) and Dutch (APX) auction-style day-ahead spot markets. A last part deals with the extension of this trilateral market to other European countries. Content: Belpex day-ahead market (DAM) (Goals of the DAM: Provide consumers with a wider choice of electrical energy sources, Enable the ARP's to optimize their portfolio in terms of imbalance costs, Reduce trade and credit risks for market players compared with the risks involved in concluding bilateral contracts, Provide economic players with a transparent price benchmark, Stimulate the opening of the electricity market); Market model Product (description, Contracts, Collateral calculation, From 12 January to launch date Corporate and Legal Aspects, Next developments); Trilateral Market Coupling (What is market coupling and what are the benefits?, Implementation of trilateral market coupling ('TLC') in France/Belgium/Netherlands, From Trilateral to Multilateral, Implementation of Trilateral Market Coupling (TLC) in France/Belgium/Netherlands, Decentralized market coupling mechanism, influence of import and export on area prices); Decentralized market coupling (2 countries Situations: unconstrained/constrained, Decentralized market coupling: 3 countries, High Level Properties of Market Coupling, Maximize flow until prices across link converge (or ATC limit reached), Power flows from low price area to high price area, Implementing a decentralized technical approach, Market Coupling Daily Process, Impact on Existing Exchange Arrangements, Implementing a decentralized contractual approach, TLC Project Process); From Trilateral to Multilateral (Geographic extensions, Towards an Open and Multilateral Market Coupling, Management of Interconnection Capacities, Interconnection Capacities: current situation, TSO Roles and Responsibilities in the TLC, Other Import/Export products on the

  10. Coupling between minimum scattering antennas

    DEFF Research Database (Denmark)

    Andersen, J.; Lessow, H; Schjær-Jacobsen, Hans

    1974-01-01

    Coupling between minimum scattering antennas (MSA's) is investigated by the coupling theory developed by Wasylkiwskyj and Kahn. Only rotationally symmetric power patterns are considered, and graphs of relative mutual impedance are presented as a function of distance and pattern parameters. Crossed...

  11. Older Couple Relationships and Loneliness

    NARCIS (Netherlands)

    de Jong Gierveld, J.; Broese van Groenou, M.; Bookwala, Jamila

    2016-01-01

    The couple relationship is a major factor in alleviating loneliness. Midlife and older adults without a couple relationship, especially after widowhood or divorce, are at serious risk of loneliness. Outcomes of empirical research, both dating back to the former century (Lopata, 1980, 1996), as well

  12. Slot-Coupled Barbel Antenna

    DEFF Research Database (Denmark)

    Jørgensen, Kasper Lüthje; Jakobsen, Kaj Bjarne

    2016-01-01

    A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant.......A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant....

  13. Time Resolved Spectroscopic Studies on a Novel Synthesized Photo-Switchable Organic Dyad and Its Nanocomposite Form in Order to Develop Light Energy Conversion Devices.

    Science.gov (United States)

    Dutta Pal, Gopa; Paul, Abhijit; Yadav, Somnath; Bardhan, Munmun; De, Asish; Chowdhury, Joydeep; Jana, Aindrila; Ganguly, Tapan

    2015-08-01

    UV-vis absorption, steady state and time resolved spectroscopic investigations in pico and nanosecond time domain were made in the different environments on a novel synthesized dyad, 3-(2-methoxynaphthalen-1-yl)-1-(4-methoxyphenyl)prop-2-en-1-one (MNTMA) in its pristine form and when combined with gold (Au) nanoparticles i.e., in its nanocomposite structure. Both steady state and time resolved measurements coupled with the DFT calculations performed by using Gaussian 03 suit of software operated in the linux operating system show that though the dyad exhibits mainly the folded conformation in the ground state but on photoexcitation the nanocomposite form of dyad prefers to be in elongated structure in the excited state indicating its photoswitchable nature. Due to the predominancy of elongated isomeric form of the dyad in the excited state in presence of Au Nps, it appears that the dyad MNTMA may behave as a good light energy converter specially in its nanocomposite form. As larger charge separation rate (kcs ~ 4 x 10(8) s-1) is found relative to the rate associated with the energy wasting charge recombination processes (kcR ~ 3 x 10(5) s-1) in the nanocomposite form of the dyad, it demonstrates the suitability of constructing the efficient light energy conversion devices with Au-dyad hybrid nanomaterials.

  14. HIV medical advances and couples.

    Science.gov (United States)

    Remien, R H

    1998-04-01

    Both parties in a couple face significant challenges in managing the relationship and the roles each play, even when only one partner is HIV-positive. Improvements following long-term combination antiretroviral therapy can change the dynamics of the relationship, particularly where one partner essentially played a caregiver role and the other partner needed special care. It takes time to work through these changing roles, and couples therapy is frequently effective. In mixed status couples, the issue of safe sexual practices is complicated by undetectable viral loads and better health; couples may cease using condoms because they are reminders of HIV. Therapists should discuss unexpressed issues, including HIV transmission concerns, changes in outlook, and feelings of uncertainty. Therapists can help a couple alter the dynamics of their relationship by normalizing the emotional impact of HIV infection.

  15. Satisfaction in male homosexual couples.

    Science.gov (United States)

    Jones, R W; Bates, J E

    1978-01-01

    Little information exists regarding factors in the satisfaction and stability of male homosexual relationships. On the basis of interviews with 14 male couples an open-ended questionnaire was developed concerning gay couples' relationships. This questionnaire and a modified version of the Marital Relationship Inventory, called here the Couples Relationship Inventory (CRI), were administered to 28 couples who described themselves as in a primary, relatively long-term relationship. Couples' descriptions of the successfulness of their relationships in conventional, heterosexual-oriented terms on the CRI were similar to their descriptions on the more homosexual-oriented, open-ended questionnaire. The study is seen as providing a point of departure for future research on gay relationships and the behavior transactions that may differentiate satisfying from unsatisfying relationships.

  16. Couple Discord and Depression in Couples during Couple Therapy and in Depressed Individuals during Depression Treatment

    Science.gov (United States)

    Atkins, David C.; Dimidjian, Sona; Bedics, Jamie D.; Christensen, Andrew

    2009-01-01

    The association between depression and relationship distress as well as the impact of treatment for the one on the other was examined across 2 treatment-seeking samples: individuals seeking treatment for depression (N = 120) and couples seeking marital therapy (N = 134 couples). Although there was a baseline association between depression and…

  17. Coupling between crossed dipole feeds

    DEFF Research Database (Denmark)

    Andersen, J.; Schjær-Jacobsen, Hans; Lessow, H.

    1974-01-01

    as a function of orientation and feeding network properties. The antennas are used as feeds for a parabolic reflector, and the effect of coupling on the secondary fields is analyzed. Especially significant is the polarization loss and it may, to some extent, be reduced by a proper choice of feeding network.......Various effects of coupling between crossed-dipole antennas are analyzed and by using an arbitrary feeding network some generality is preserved. With one cross excited and another cross acting as a parasitic loaded antenna, coupling losses and gain and polarization losses are presented...

  18. Coupling spin qubits via superconductors

    DEFF Research Database (Denmark)

    Leijnse, Martin; Flensberg, Karsten

    2013-01-01

    We show how superconductors can be used to couple, initialize, and read out spatially separated spin qubits. When two single-electron quantum dots are tunnel coupled to the same superconductor, the singlet component of the two-electron state partially leaks into the superconductor via crossed...... Andreev reflection. This induces a gate-controlled singlet-triplet splitting which, with an appropriate superconductor geometry, remains large for dot separations within the superconducting coherence length. Furthermore, we show that when two double-dot singlet-triplet qubits are tunnel coupled...

  19. Anomalous couplings at LEP2

    International Nuclear Information System (INIS)

    Fayolle, D.

    2002-01-01

    In its second phase, LEP has allowed to study four fermion processes never observed before. Results are presented on the charged triple gauge boson couplings (TGC) from the W-pair, Single W and Single γ production. The anomalous quartic gauge couplings (QGC) are constrained using production of WWγ, νν-barγγ and Z γγ final states. Finally, limits on the neutral anomalous gauge couplings (NGC) using the Z γ and ZZ production processes are also reported. All results are consistent with the Standard Model expectations. (authors)

  20. Overprotection in couples with aphasia.

    Science.gov (United States)

    Croteau, C; Le Dorze, G

    1999-09-01

    The study aimed to measure the perception of overprotection in 21 couples living with aphasia, relative to controls. The 'Questionnaire on Resources and Stress' assessed the spouses' perception and the 'Overprotection Scale for Adults' measured the perception of persons with aphasia. Husbands of women with aphasia did not differ from husbands of women without aphasia. Wives of men with aphasia reported more overprotection than wives of men without aphasia, even when functional impairment was controlled. The men with aphasia did not report feeling overprotected. No significant relationship was uncovered between the report of overprotection and feeling overprotected in couples with aphasia. Overprotection is present in some couples coping with aphasia.

  1. Substrate noise coupling in RFICs

    CERN Document Server

    Helmy, Ahmed

    2008-01-01

    Substrate Noise Coupling in RFICs addresses substrate noise coupling in RF and mixed signal ICs when used in a system on chip (SoC) containing digital ICs as well. This trend of integrating RF, mixed signal ICs with large digital ICs is found in many of today's commercial ICs such as single chip Wi-Fi or Bluetooth solutions and is expected to grow rapidly in the future. The book reports modeling and simulation techniques for substrate noise coupling effects in RFICs and introduces isolation structures and design guides to mitigate such effects with the ultimate goal of enhancing the yield of R

  2. Gay Couple Counseling: Proceedings of a Conference

    Science.gov (United States)

    Blair, Ralph; And Others

    1974-01-01

    This is a report of a conference on gay couple counseling for members of the helping professions. Discussion topics included (1) Therapists' Panel on Female Couples, (2) Therapists' Panel on Male Couples; (3) Panel of Male Couples and (4) Panel of Female Couples. The conference was held in May, 1974 in New York and was sponsored by The Homosexual…

  3. Theory of coupled Landau damping

    CERN Document Server

    Métral, Elias

    1999-01-01

    The influence of linear coupling between the transverse planes on Landau damping of coherent instabilities is assessed using two typical frequency distributions (Lorentzian, , and "elliptical", where ). A general stability criterion is derived in both cases that includes the coupling strength and the distance from the resonance It reveals the possibility of sharing the "stabilising" frequency spreads between the two planes. This can significantly improve the coherent beam stability, especially in cases where the situation is more critical in one plane. Another important observation is the fact that the influence of a large imaginary part in the beam-environment impedance, which normally requires a large frequency spread for Landau damping, can be compensated (at least in one plane) by a judicious choice of the coupling. The conjunction of these two features could explain why a machine like the CERN-PS can be stabilised by tuning close to a coupling resonance and can be used to determine optimum values for the...

  4. Heterogeneous Dynamics of Coupled Vibrations

    NARCIS (Netherlands)

    Cringus, Dan; Jansen, Thomas I. C.; Pshenichnikov, Maxim S.; Schoenlein, RW; Corkum, P; DeSilvestri, S; Nelson, KA; Riedle, E

    2009-01-01

    Frequency-dependent dynamics of coupled stretch vibrations of a water molecule are revealed by 2D IR correlation spectroscopy. These are caused by non-Gaussian fluctuations of the environment around the individual OH stretch vibrations.

  5. Spatial coupling in heterogeneous catalysis

    Science.gov (United States)

    Yamamoto, S. Y.; Surko, C. M.; Maple, M. B.

    1995-11-01

    Spatial coupling mechanisms are studied in the heterogeneous catalytic oxidation of carbon monoxide over platinum at atmospheric pressure under oscillatory conditions. Experiments are conducted in a continuous flow reactor, and the reaction rate is monitored using both infrared imaging and thermocouples. The catalysts are in the form of platinum annular thin films on washer-shaped quartz substrates, and they provide highly repeatable oscillatory behavior. Oscillations are typically spatially synchronized with the entire catalyst ``flashing'' on and off uniformly. Spatial coupling is investigated by introducing various barriers which split the annular ring in half. Infrared images show that coupling through the gas phase dominates coupling via the diffusion of CO on the surface or heat diffusion through the substrate. The introduction of a localized heat perturbation to the catalyst surface does not induce a transition in the reaction rate. Thus, it is likely that the primary mode of communication is through the gas-phase diffusion of reactants.

  6. Damping of coupled harmonic oscillators

    Science.gov (United States)

    Dolfo, Gilles; Vigué, Jacques

    2018-03-01

    When two harmonic oscillators are coupled in the presence of damping, their dynamics exhibit two very different regimes depending on the relative magnitude of the coupling and damping terms At resonance, when the coupling has its largest effect, if the coupling dominates the damping, there is a periodic exchange of energy between the two oscillators while, in the opposite case, the energy transfer from one oscillator to the other one is irreversible. We prove that the border between these two regimes goes through an exceptional point and we briefly explain what is an exceptional point. The present paper is written for undergraduate students, with some knowledge in classical mechanics, but it may also be of interest for graduate students.

  7. Coupled Acoustic-Mechanical Bandgaps

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard; Kook, Junghwan

    2016-01-01

    In this work, we study the existence of coupled bandgaps for corrugated plate structures and acoustic channels. The study is motivated by the observation that the performance of traditional bandgap structures, such as periodic plates, may be compromised due to the coupling to a surrounding acoustic...... medium and the presence of acoustic resonances. It is demonstrated that corrugation of the plate structure can introduce bending wave bandgaps and bandgaps in the acoustic domain in overlapping and audible frequency ranges. This effect is preserved also when taking the physical coupling between the two...... domains into account. Additionally, the coupling is shown to introduce extra gaps in the band structure due to modal interaction and the appearance of a cut-on frequency for the fundamental acoustic mode....

  8. Marital Dissolution Among Interracial Couples

    OpenAIRE

    Zhang, Yuanting; Van Hook, Jennifer

    2009-01-01

    Increases in interracial marriage have been interpreted as reflecting reduced social distance among racial and ethnic groups, but little is known about the stability of interracial marriages. Using six panels of Survey of Income and Program Participation (N = 23,139 married couples), we found that interracial marriages are less stable than endogamous marriages, but these findings did not hold up consistently. After controlling for couple characteristics, the risk of divorce or separation amon...

  9. Digital fluoroscopy with an optically coupled charge-coupled device

    Science.gov (United States)

    Liu, Hong

    1992-07-01

    This research was aimed at investigating the potential of developing an optically coupled charge-coupled device (CCD) imaging system for some digital fluoroscopic applications. The viability of this concept for fluoroscopic imaging was studied with respect to image intensifier-television (II-TV) techniques. The anticipated advantages of the optically coupled CCD, compared with II-TV, include higher contrast sensitivity, larger dynamic range, moderate spatial resolution and clinically acceptable dose. Following an investigation of some theoretical and practical issues concerning the optical coupling efficiency between the intensifying screen and the CCD imager, mathematical methods were developed to relate the signal, signal-to-noise ratio, and x-ray quantum efficiency of the optically coupled CCD imaging chain. The spatial resolution of the system was also analyzed. Using an ultra-sensitive CCD, as well as improved scintillating and optical coupling techniques, we built a laboratory system for experiments. We conducted measurements of the modulation transfer function (MTF), contrast sensitivity, contrast-detail detectability and detector contrast. The results suggest that the lesion detectability of our sub-optimal system was comparable to that of a screen-film technique under the same radiation dose, and was significantly better than II-TV fluoroscopy. Potential clinical applications of our system include mammography, pre-operational localization, pediatric chest radiography, and single tracer autoradiography. Images of selected phantoms, pathological specimens and small animals were acquired to demonstrate the radiologic quality attainable for such procedures. We conclude that developing an x-ray quantum limited, pseudo-real time, digital fluoroscopic imaging system (for some applications) without an II appears to be theoretically and technically feasible. The successful development of optically coupled CCD fluoroscopy has the potential for improving the quality

  10. Development of annular coupled structure

    International Nuclear Information System (INIS)

    Kageyama, T.; Morozumi, Y.; Yoshino, K.; Yamazaki, Y.

    1992-01-01

    A π/2-mode standing-wave linac of an Annular Coupled Structure (ACS) has been developed for the 1-GeV proton linac of the Japanese Hadron Project (JHP). This ACS has four coupling slots between accelerating and coupling cells in order to overcome difficulties in putting the ACS to practical use. Two prototypes of a four-slot ACS (f = 1296 MHz, β = v/c = 0.8) have been constructed and tested: one with a staggered slot-orientation from cell to cell; and the other with a uniform one. The staggered configuration gives a larger coupling constant and a larger shunt impedance than the uniform one with the same size of coupling slot. Both models have been conditioned up to the design input RF power. The four-slot ACS gives a distortion-free accelerating field around the beam axis, while a Side-Coupled Structure cavity gives an accelerating field mixed with a TE111-like mode. (Author) 7 figs., 2 tabs., 9 refs

  11. Generation of higher dimensional entangled states in quantum Rabi systems

    Science.gov (United States)

    Albarrán-Arriagada, F.; Alvarado Barrios, G.; Cárdenas-López, F. A.; Romero, G.; Retamal, J. C.

    2017-05-01

    We present protocols for the generation of high-dimensional entangled states of anharmonic oscillators by means of coherent manipulation of light-matter systems in the ultrastrong coupling regime. Our protocols consider a pair of ultrastrong coupled qubit-cavity systems, each coupled to an ancilla qubit, and combine classical pulses plus the selection rules imposed by the parity symmetry. We study the robustness of the entangling protocols under dissipative effects. This proposal may have applications within state-of-art circuit quantum electrodynamics.

  12. Loop-to-loop coupling.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Lucero, Larry Martin; Langston, William L.; Salazar, Robert Austin; Coleman, Phillip Dale; Basilio, Lorena I.; Bacon, Larry Donald

    2012-05-01

    This report estimates inductively-coupled energy to a low-impedance load in a loop-to-loop arrangement. Both analytical models and full-wave numerical simulations are used and the resulting fields, coupled powers and energies are compared. The energies are simply estimated from the coupled powers through approximations to the energy theorem. The transmitter loop is taken to be either a circular geometry or a rectangular-loop (stripline-type) geometry that was used in an experimental setup. Simple magnetic field models are constructed and used to estimate the mutual inductance to the receiving loop, which is taken to be circular with one or several turns. Circuit elements are estimated and used to determine the coupled current and power (an equivalent antenna picture is also given). These results are compared to an electromagnetic simulation of the transmitter geometry. Simple approximate relations are also given to estimate coupled energy from the power. The effect of additional loads in the form of attached leads, forming transmission lines, are considered. The results are summarized in a set of susceptibility-type curves. Finally, we also consider drives to the cables themselves and the resulting common-to-differential mode currents in the load.

  13. Systemic couple therapy for dysthymia.

    Science.gov (United States)

    Montesano, Adrián; Feixas, Guillem; Muñoz, Dámaris; Compañ, Victoria

    2014-03-01

    We examined the effect of Systemic Couple Therapy on a patient diagnosed with dysthymic disorder and her partner. Marge and Peter, a middle-aged married couple, showed significant and meaningful changes in their pattern of interaction over the course of the therapy and, by the end of it, Marge no longer met the diagnostic criteria for dysthymic disorder. Her scores on the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) and Beck Depression Inventory, Second Edition (BDI-II) were in the clinical range before treatment and in the nonclinical one at the end of therapy. Although scores on Dyadic Adjustment Scale showed different patterns, both members reported significant improvement. The analysis of change in the alliance-related behaviors throughout the process concurred with change in couple's pattern of interaction. Treatment effects were maintained at 12-month follow-up. Highlights in the therapy process showed the importance of relational mechanisms of change, such as broadening the therapeutic focus into the couple's pattern of interaction, reducing expressed emotion and resentment, as well as increasing positive exchanges. The results of this evidence-based case study should prompt further investigation of couple therapy for dysthymia disorder. Randomized clinical trial design is needed to reach an evidence-based treatment status. (c) 2014 APA, all rights reserved.

  14. Matter couplings in supergravity theories

    International Nuclear Information System (INIS)

    Bagger, J.A.

    1983-01-01

    The N = 1 supersymmetric nonlinear sigma model is coupled to supergravity. The results are expressed in the language of Kahler geometry. Topological considerations constrain the scalar fields to lie on a Kahler manifold of restricted type, or a Hodge manifold. For topologically nontrivial manifolds, this leads to the quantization of Newton's constant in terms of the scalar self-coupling. The isometries of the N = 1 model are gauged. This gives a geometrical picture of what might be called the gauge invariant supersymmetric nonlinear sigma model. It also provides a new interpretation of the Fayet-Iliopoulos D-term. The gauge invariant supersymmetric nonlinear sigma model is coupled to N = 1 supergravity. This leads to a deeper understanding of the connections between supergravity, R-invariance and the Fayet-Iliopoulos D-term. It also provides a foundation for phenomenological studies of supergravity theories. Finally, the N = 2 supersymmetric nonlinear sigma model is coupled to supergravity. The scalar fields are found to lie on a negatively curved quaternionic manifold. This implies that matter self-couplings that are allowed in N = 2 supersymmetry are forbidden in N = 2 supergravity, and vice versa

  15. Trilateral market coupling. Algorithm appendix

    International Nuclear Information System (INIS)

    2006-03-01

    Market Coupling is both a mechanism for matching orders on the exchange and an implicit cross-border capacity allocation mechanism. Market Coupling improves the economic surplus of the coupled markets: the highest purchase orders and the lowest sale orders of the coupled power exchanges are matched, regardless of the area where they have been submitted; matching results depend however on the Available Transfer Capacity (ATC) between the coupled hubs. Market prices and schedules of the day-ahead power exchanges of the several connected markets are simultaneously determined with the use of the Available Transfer Capacity defined by the relevant Transmission System Operators. The transmission capacity is thereby implicitly auctioned and the implicit cost of the transmission capacity from one market to the other is the price difference between the two markets. In particular, if the transmission capacity between two markets is not fully used, there is no price difference between the markets and the implicit cost of the transmission capacity is null. Market coupling relies on the principle that the market with the lowest price exports electricity to the market with the highest price. Two situations may appear: either the Available Transfer Capacity (ATC) is large enough and the prices of both markets are equalized (price convergence), or the ATC is too small and the prices cannot be equalized. The Market Coupling algorithm takes as an input: 1 - The Available Transfer Capacity (ATC) between each area for each flow direction and each Settlement Period of the following day (i.e. for each hour of following day); 2 - The (Block Free) Net Export Curves (NEC) of each market for each hour of the following day, i.e., the difference between the total quantity of Divisible Hourly Bids and the total quantity of Divisible Hourly Offers for each price level. The NEC reflects a market's import or export volume sensitivity to price. 3 - The Block Orders submitted by the participants in

  16. John Bowlby and couple psychotherapy.

    Science.gov (United States)

    Clulow, Christopher

    2007-12-01

    The centenary of John Bowlby's birth provides a context for considering the policy, research and practice legacies that he left for practitioners working in many different fields supporting couples and families. Part historical, and part forwardlooking, this paper considers the links between attachment in the infant-parent dyad that was at the heart of Bowlby's concern and the nature of the affective ties that bind couples together in adult romantic relationships. An overview of the influence of his theory on family policy and adult attachment research is followed by an appreciation of its significance for the practice of couple psychotherapy. The paper concludes with a comment on the implications of current neuroscience knowledge for therapeutic technique.

  17. Chameleons with Field Dependent Couplings

    CERN Document Server

    Brax, Philippe; Mota, David F; Nunes, Nelson J; Winther, Hans A

    2010-01-01

    Certain scalar-tensor theories exhibit the so-called chameleon mechanism, whereby observational signatures of scalar fields are hidden by a combination of self-interactions and interactions with ambient matter. Not all scalar-tensor theories exhibit such a chameleon mechanism, which has been originally found in models with inverse power run-away potentials and field independent couplings to matter. In this paper we investigate field-theories with field-dependent couplings and a power-law potential for the scalar field. We show that the theory indeed is a chameleon field theory. We find the thin-shell solution for a spherical body and investigate the consequences for E\\"ot-Wash experiments, fifth-force searches and Casimir force experiments. Requiring that the scalar-field evades gravitational tests, we find that the coupling is sensitive to a mass-scale which is of order of the Hubble scale today.

  18. Strong coupling phase in QED

    International Nuclear Information System (INIS)

    Aoki, Ken-ichi

    1988-01-01

    Existence of a strong coupling phase in QED has been suggested in solutions of the Schwinger-Dyson equation and in Monte Carlo simulation of lattice QED. In this article we recapitulate the previous arguments, and formulate the problem in the modern framework of the renormalization theory, Wilsonian renormalization. This scheme of renormalization gives the best understanding of the basic structure of a field theory especially when it has a multi-phase structure. We resolve some misleading arguments in the previous literature. Then we set up a strategy to attack the strong phase, if any. We describe a trial; a coupled Schwinger-Dyson equation. Possible picture of the strong coupling phase QED is presented. (author)

  19. Coupled-Beam and Coupled-Bunch Instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Burov, Alexey [Fermilab

    2016-06-23

    A problem of coupled-beam instability is solved for two multibunch beams with slightly different revolution frequencies, as in the Fermilab Recycler Ring (RR). Sharing of the inter-bunch growth rates between the intra-bunch modes is described. The general analysis is applied to the RR; possibilities to stabilize the beams by means of chromaticity, feedback and Landau damping are considered.

  20. Fertility prognosis for infertile couples

    DEFF Research Database (Denmark)

    Bostofte, E; Bagger, P; Michael, A

    1993-01-01

    OBJECTIVE: To develop a fertility prognosis model for infertile couples. DESIGN: Prospective follow-up study. PARTICIPANTS: In the period November 30, 1977 to June 1, 1985, 321 consecutive couples were investigated for infertility at Hvidovre University Hospital. Investigation of the female...... MEASURE: The Cox regression model was used to predict the time required to conceive based on informations provided by fertility investigations. RESULTS: Three of 16 prognostic variables (the period of infertility, the female infertility factor, and the P-test) possess significant prognostic information...

  1. Tunable coupled surface acoustic cavities

    Science.gov (United States)

    de Lima, M. M.; Santos, P. V.; Kosevich, Yu. A.; Cantarero, A.

    2012-06-01

    We demonstrate the electric tuning of the acoustic field in acoustic microcavities (MCs) defined by a periodic arrangement of metal stripes within a surface acoustic delay line on LiNbO3 substrate. Interferometric measurements show the enhancement of the acoustic field distribution within a single MC, the presence of a "bonding" and "anti-bonding" modes for two strongly coupled MCs, as well as the positive dispersion of the "mini-bands" formed by five coupled MCs. The frequency and amplitude of the resonances can be controlled by the potential applied to the metal stripes.

  2. Dark coupling and gauge invariance

    International Nuclear Information System (INIS)

    Gavela, M.B.; Honorez, L. Lopez; Mena, O.; Rigolin, S.

    2010-01-01

    We study a coupled dark energy-dark matter model in which the energy-momentum exchange is proportional to the Hubble expansion rate. The inclusion of its perturbation is required by gauge invariance. We derive the linear perturbation equations for the gauge invariant energy density contrast and velocity of the coupled fluids, and we determine the initial conditions. The latter turn out to be adiabatic for dark energy, when assuming adiabatic initial conditions for all the standard fluids. We perform a full Monte Carlo Markov Chain likelihood analysis of the model, using WMAP 7-year data

  3. Flashing coupled density wave oscillation

    International Nuclear Information System (INIS)

    Jiang Shengyao; Wu Xinxin; Zhang Youjie

    1997-07-01

    The experiment was performed on the test loop (HRTL-5), which simulates the geometry and system design of the 5 MW reactor. The phenomenon and mechanism of different kinds of two-phase flow instabilities, namely geyser instability, flashing instability and flashing coupled density wave instability are described. The especially interpreted flashing coupled density wave instability has never been studied well, it is analyzed by using a one-dimensional non-thermo equilibrium two-phase flow drift model computer code. Calculations are in good agreement with the experiment results. (5 refs.,5 figs., 1 tab.)

  4. Cation-Coupled Bicarbonate Transporters

    OpenAIRE

    Aalkjaer, Christian; Boedtkjer, Ebbe; Choi, Inyeong; Lee, Soojung

    2014-01-01

    Cation-coupled HCO3− transport was initially identified in the mid-1970s when pioneering studies showed that acid extrusion from cells is stimulated by CO2/HCO3− and associated with Na+ and Cl− movement. The first Na+-coupled bicarbonate transporter (NCBT) was expression-cloned in the late 1990s. There are currently five mammalian NCBTs in the SLC4-family: the electrogenic Na,HCO3-cotransporters NBCe1 and NBCe2 (SLC4A4 and SLC4A5 gene products); the electroneutral Na,HCO3-cotransporter NBCn1 ...

  5. Coupling to photonic crystal fibers

    DEFF Research Database (Denmark)

    Hougaard, Kristian G.; Bjarklev, Anders Overgaard; Knudsen, Erik

    2002-01-01

    In this work we have analyzed the correspondence between the fundamental mode of PCFs and Gaussian modes as a function of frequency, pitch, and air hole size. Such analysis provides insight into design space regions of PCFs, where low-loss coupling to standard fibers may be obtained.......In this work we have analyzed the correspondence between the fundamental mode of PCFs and Gaussian modes as a function of frequency, pitch, and air hole size. Such analysis provides insight into design space regions of PCFs, where low-loss coupling to standard fibers may be obtained....

  6. Analysis of some coplanar transmission lines: coplanar coupled lines, coplanar coupled striplines, and coplanar coupled lines with rectangular microshield

    Science.gov (United States)

    Yuan, Naichang; He, Jianguo; Yao, Demiao; Dai, Qin; Lin, Weigan

    1995-06-01

    Two types of coplanar transmission lines, rectangular microshield coplanar coupled lines (RMCCL) and coplanar coupled rectangular microshield lines (CCRML), are proposed for MMIC applications. These are developed from coplanar coupled lines (CCL) and coplanar coupled strip lines (CCS). Analytic formulas are presented for calculating the quasistatic TEM parameters of these coupled lines by means of exact conformal mapping techniques. Numerical results are also presented to illustrate the properties of these coplanar transmission lines.

  7. Treating infidelity in same-sex couples.

    Science.gov (United States)

    Martell, Christopher R; Prince, Stacey E

    2005-11-01

    Psychotherapy with same-sex couples does not differ markedly from standard couple therapies; this is also true for treating couples facing infidelity. However, same-sex couples often design their relationships differently, without tradition and formal marital contracts to prescribe behavior. Based on clinical experience and the empirical research, this article addresses the differing norms involved in affirmatively treating infidelity in gay and lesbian couples within the framework of integrative behavioral couple therapy (IBCT). Two cases illustrate the process and outcome of IBCT with same-sex couples.

  8. Couples Therapy: An Adlerian Perspective.

    Science.gov (United States)

    Kern, Roy M.; And Others

    This book provides therapists with a theoretical base from which to view the dynamics of couples' relationships and the therapeutic process. The book's eight chapters are organized into three parts: "Adlerian Theory and Process"; "Therapeutic Interventions"; and "Special Issues in Marital Therapy." Chapter 1, Adlerian…

  9. Hyperchaos in coupled Colpitts oscillators

    DEFF Research Database (Denmark)

    Cenys, Antanas; Tamasevicius, Arunas; Baziliauskas, Antanas

    2003-01-01

    The paper suggests a simple solution of building a hyperchaotic oscillator. Two chaotic Colpitts oscillators, either identical or non-identical ones are coupled by means of two linear resistors R-k. The hyperchaotic output signal v(t) is a linear combination, specifically the mean of the individual...

  10. Palladium-Catalysed Coupling Reactions

    NARCIS (Netherlands)

    de Vries, Johannes G.; Beller, M; Blaser, HU

    2012-01-01

    Palladium-catalysed coupling reactions have gained importance as a tool for the production of pharmaceutical intermediates and to a lesser extent also for the production of agrochemicals, flavours and fragrances, and monomers for polymers. In this review only these cases are discussed where it seems

  11. Cleaved-Coupled Nanowire Lasers

    Science.gov (United States)

    2013-01-15

    nanowires with a 40-nm gap show significant modulation of the threshold gain among different lasing modes (Fig. 4, blue dia- monds ). Within the...spectrometer (Princeton Instruments/Acton) equipped with a 1,200-groove/mm grating blazed at 300 nm and a liquid N2-cooled charge-coupled device. The

  12. Inductively coupled helium plasma torch

    Science.gov (United States)

    Montaser, Akbar; Chan, Shi-Kit; Van Hoven, Raymond L.

    1989-01-01

    An inductively coupled plasma torch including a base member, a plasma tube and a threaded insert member within the plasma tube for directing the plasma gas in a tangential flow pattern. The design of the torch eliminates the need for a separate coolant gas tube. The torch can be readily assembled and disassembled with a high degree of alignment accuracy.

  13. Marital Dissolution among Interracial Couples

    Science.gov (United States)

    Zhang, Yuanting; Van Hook, Jennifer

    2009-01-01

    Increases in interracial marriage have been interpreted as reflecting reduced social distance among racial and ethnic groups, but little is known about the stability of interracial marriages. Using six panels of Survey of Income and Program Participation (N = 23,139 married couples), we found that interracial marriages are less stable than…

  14. Perovskite catalysts for oxidative coupling

    Science.gov (United States)

    Campbell, Kenneth D.

    1991-01-01

    Perovskites of the structure A.sub.2 B.sub.2 C.sub.3 O.sub.10 are useful as catalysts for the oxidative coupling of lower alkane to heavier hydrocarbons. A is alkali metal; B is lanthanide or lanthanum, cerium, neodymium, samarium, praseodymium, gadolinium or dysprosium; and C is titanium.

  15. Magnetically coupled system for mixing

    Energy Technology Data Exchange (ETDEWEB)

    Miller, III, Harlan; Meichel, George; Legere, Edward; Malkiel, Edwin; Woods, Robert Paul; Ashley, Oliver; Katz, Joseph; Ward, Jason; Petersen, Paul

    2015-09-22

    The invention provides a mixing system comprising a magnetically coupled drive system and a foil for cultivating algae, or cyanobacteria, in an open or enclosed vessel. The invention provides effective mixing, low energy usage, low capital expenditure, and ease of drive system component maintenance while maintaining the integrity of a sealed mixing vessel.

  16. Latinos' Perceptions of Interethnic Couples

    Science.gov (United States)

    Garcia, Amber L.; Riggio, Heidi R.; Palavinelu, Subha; Culpepper, Lane Locher

    2012-01-01

    Numerous survey findings indicate that the majority of White Americans are accepting of interracial romantic relationships. However, relatively few studies have looked at how different American ethnic minority groups view such relationships. The current research examined Latinos' evaluations of intraethnic and interethnic couples. Latino…

  17. Coupled optical resonance laser locking

    CSIR Research Space (South Africa)

    Burd, CC

    2014-10-01

    Full Text Available We have demonstrated simultaneous laser frequency stabilization of a UV and IR laser, to coupled transitions of ions in the same spectroscopic sample, by detecting only the absorption of the UV laser. Separate signals for locking the different...

  18. Acoustical coupling of lizard eardrums

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, Jakob; Manley, Geoffrey A

    2008-01-01

    Lizard ears are clear examples of two-input pressure-difference receivers, with up to 40-dB differences in eardrum vibration amplitude in response to ipsi- and contralateral stimulus directions. The directionality is created by acoustical coupling of the eardrums and interaction of the direct...

  19. Advances in HIV Prevention for Serodiscordant Couples

    OpenAIRE

    Muessig, Kathryn E.; Cohen, Myron S.

    2014-01-01

    Serodiscordant couples play an important role in maintaining the global HIV epidemic. This review summarizes biobehavioral and biomedical HIV prevention options for serodiscordant couples focusing on advances in 2013 and 2014, including World Health Organization guidelines and best-evidence for couples counseling, couples-based interventions, and the use of antiviral agents for prevention. In the past few years marked advances have been made in HIV prevention for serodiscordant couples and nu...

  20. A palladium-catalysed multicomponent coupling approach to conjugated poly(1,3-dipoles) and polyheterocycles

    OpenAIRE

    Leitch, David C.; Kayser, Laure V.; Han, Zhi-Yong; Siamaki, Ali R.; Keyzer, Evan N.; Gefen, Ashley; Arndtsen, Bruce A.

    2015-01-01

    Conjugated polymers have emerged over the past several decades as key components for a range of applications, including semiconductors, molecular wires, sensors, light switchable transistors and OLEDs. Nevertheless, the construction of many such polymers, especially highly substituted variants, typically involves a multistep synthesis. This can limit the ability to both access and tune polymer structures for desired properties. Here we show an alternative approach to synthesize conjugated mat...

  1. Switchable Polarization in Mn Embedded Graphene.

    Science.gov (United States)

    Noor-A-Alam, Mohammad; Ullah, Hamid; Shin, Young-Han

    2018-03-14

    Graphene, despite its many unique properties, is neither intrinsically polar due to inversion symmetry nor magnetic. However, based on density functional theory, we find that Mn, one of transition metals, embedded in single or double vacancy (Mn@SV and Mn@DV) in a graphene monolayer induces a dipole moment perpendicular to the sheet, which can be switched from up to down by Mn penetration through the graphene. Such switching could be realized by an external stimuli introduced through the tip of a scanning probe microscope, as already utilized in the studies of molecular switches. We estimate the energy barriers for dipole switching, which are found to be 2.60 eV and 0.28 eV for Mn@SV and Mn@DV, respectively. However, by applying biaxial tensile strain, we propose a mechanism for tuning the barrier. We find that 10% biaxial tensile strain, which is already experimentally achievable in graphene-like two-dimensional materials, can significantly reduce the barrier to 0.16 eV in Mn@SV. Moreover, in agreement with previous studies, we find a high magnetic moment of 3 μ B for both Mn@SV and Mn@DV, promising the potential of these structures in spintronics as well as in nanoscale electro-mechanical or memory devices.

  2. Switchable adhesion by chemical functionality and topography

    NARCIS (Netherlands)

    Kamperman, M.M.G.; Synytska, A.

    2012-01-01

    Progress in adhesion technology over the last few decades has led to widespread replacement of mechanical fasteners with adhesive bonds. Despite the advances, it remains challenging to produce materials that are sticky on demand. In this feature article we highlight recent efforts to develop

  3. Switchable solvents and methods of use thereof

    Science.gov (United States)

    Jessop, Philip G [Kingston, CA; Eckert, Charles A [Atlanta, GA; Liotta, Charles L [Atlanta, GA; Heldebrant, David J [Richland, WA

    2011-07-19

    A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

  4. Shape-Memory PVDF Exhibiting Switchable Piezoelectricity.

    Science.gov (United States)

    Hoeher, Robin; Raidt, Thomas; Novak, Nikola; Katzenberg, Frank; Tiller, Joerg C

    2015-12-01

    In this study, a material is designed which combines the properties of shape-memory and electroactive polymers. This is achieved by covalent cross-linking of polyvinylidene fluoride. The resulting polymer network exhibits excellent shape-memory properties with a storable strain of 200%, and fixity as well as recovery values of 100%. Programming upon rolling induces the transformation from the nonelectroactive α-phase to the piezoelectric β-phase. The highest β-phase content is found to be 83% for a programming strain of 200% affording a d33 value of -30 pm V(-1). This is in good accordance with literature known values for piezoelectric properties. Thermal triggering this material does not only result in a shape change but also renders the material nonelectroactive. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Electrically switchable chromogenic materials for external glazing

    Energy Technology Data Exchange (ETDEWEB)

    Cupelli, Daniela; Nicoletta, Fiore Pasquale [Dipartimento di Scienze Farmaceutiche, Universita della Calabria, 87036 Rende (CS) (Italy); Manfredi, Sabrina; Filpo, Giovanni De; Chidichimo, Giuseppe [Dipartimento di Chimica, Universita della Calabria, 87036 Rende (CS) (Italy)

    2009-03-15

    The development of chromogenic materials is important for their potential applications as electrically adjustable or thermally self-adjusting light and heat filters in the external glazing of buildings. Recently, we have reported our investigations on electrolyte-liquid crystal dispersions, which show independent electro-optical and electrochromic properties characterized by fast bleaching times. Nevertheless, for the external glazing of buildings, it is recommended to have a transparent off state, which turns opaque upon application of the external field. In this paper, we present our efforts to homeotropically align by rough surfaces fluid mixtures of a low molecular mass liquid crystal with a negative dielectric anisotropy, a liquid crystalline monomer, and electrolyte molecules in order to obtain transparent films after a polymerization process. Upon application of an ac electric field, the device becomes opaque and if a dc field is added, the cell changes colour too. We have also investigated the relationship between electro-optical/chromogenic response and physical chemical properties of the components. (author)

  6. Development of Switchable Polarity Solvent Draw Solutes

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Aaron D.

    2016-11-01

    Results of a computational fluid dynamic (CFD) study of flow and heat transfer in a printed circuit heat exchanger (PCHE) geometry are presented. CFD results obtained from a two-plate model are compared to corresponding experimental results for the validation. This process provides the basis for further application of the CFD code to PCHE design and performance analysis in a variety of internal flow geometries. As a part of the code verification and validation (V&V) process, CFD simulation of a single semicircular straight channel under laminar isothermal conditions was also performed and compared to theoretical results. This comparison yielded excellent agreement with the theoretical values. The two-plate CFD model based on the experimental PCHE design overestimated the effectiveness and underestimated the pressure drop. However, it is found that the discrepancy between the CFD result and experimental data was mainly caused by the uncertainty in the geometry of heat exchanger during the fabrication. The CFD results obtained using a slightly smaller channel diameter yielded good agreement with the experimental data. A separate investigation revealed that the average channel diameter of the OSU PCHE after the diffusion-bonding was 1.93 mm on the cold fluid side and 1.90 mm on the hot fluid side which are both smaller than the nominal design value. Consequently, the CFD code was shown to have sufficient capability to evaluate the heat exchanger thermal-hydraulic performance.

  7. Switchable Shape Memory Alloys (SMA) Thermal Materials

    Data.gov (United States)

    National Aeronautics and Space Administration — Materials and systems are being designed and developed to meet complex operational requirements while being kept lightweight, efficient, and robust. Multifunctional...

  8. Interpersonal Couplings in Human Interactions

    Science.gov (United States)

    Shockley, Kevin; Riley, Michael A.

    As inherently social beings people routinely interact with others. Interpersonal activities such as dancing, conversation, or team sports require people to coordinate at several different levels, ranging from the coordination of physical movements and physiological states of the body to the coordination of mental states and cognitive or linguistic activity. One of the challenges confronted by researchers in this interdisciplinary field has been to find ways to objectively quantify interpersonal coupling on the basis of brief, noisy, nonstationary, and complex time series of human behavioral sequences. Given their robustness to these challenges, recurrence-based strategies have played a very important role in the development of this field of research. This chapter provides a review of current behavioral, cognitive, and physiological research that has used recurrence methods to quantify interpersonal coupling.

  9. Fertility prognosis for infertile couples

    DEFF Research Database (Denmark)

    Bostofte, E; Bagger, P; Michael, A

    1993-01-01

    OBJECTIVE: To develop a fertility prognosis model for infertile couples. DESIGN: Prospective follow-up study. PARTICIPANTS: In the period November 30, 1977 to June 1, 1985, 321 consecutive couples were investigated for infertility at Hvidovre University Hospital. Investigation of the female...... MEASURE: The Cox regression model was used to predict the time required to conceive based on informations provided by fertility investigations. RESULTS: Three of 16 prognostic variables (the period of infertility, the female infertility factor, and the P-test) possess significant prognostic information....... The period of infertility and the P-test are best scored as continuous variables, whereas the female infertility factor are best categorized in four classes, i.e., normal, ovulation or cervical disorder, anatomic disorder, or a combination of disorders. CONCLUSIONS: The three prognostic variables...

  10. Tunneling of a coupled system

    International Nuclear Information System (INIS)

    Avishai, Y.

    1985-01-01

    We consider tunneling through a potential barrier V(x) in the presence of a coupling term W(x,y). Let H(y) be the internal Hamiltonian associated with the coordinate y and let E 0 (x) be the ground state energy of the operator H(x;y) = H(y) + W(x,y) in which x is a parameter. Our result for the tunneling probability (in the WKB approximation) is P = exp(2i ∫ k 0 (x)dx) where, at energy E, k 0 (x) = [E-E 0 (x)-V(x)]sup(1/2)/(h/2π) is the local wave number in the presence of coupling. (orig.)

  11. [Informations for the infertile couple].

    Science.gov (United States)

    Oger, P; Nicollet, B; Wainer, B; de Crécy, M-A

    2010-12-01

    The aim of the first consultation related to infertility is supposed to be the optimization of all factors that can increase the chances of pregnancy: more frequent sexual intercourse during the fertility windows; lifestyle modifications (better diet, decreased exposure to tobacco or other toxics); older couples can enjoy the same advice but should be proposed a quicker medical support. Maternal preconceptional advice must be transmitted. A testicular cancer must always be excluded in infertile men, while the risk of hormone-dependent cancers in infertile women remains undetermined. With the results of this first consultation, couples will generally be proposed the best solution to achieve their parental project: ovarian stimulation assisted reproductive technology (IUI, IVF or ICSI) or adoption. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

  12. Modulational instability of coupled waves

    International Nuclear Information System (INIS)

    McKinstrie, C.J.; Bingham, R.

    1989-01-01

    The collinear propagation of an arbitrary number of finite-amplitude waves is modeled by a system of coupled nonlinear Schroedinger equations; one equation for each complex wave amplitude. In general, the waves are modulationally unstable with a maximal growth rate larger than the modulational growth rate of any wave alone. Moreover, waves that are modulationally stable by themselves can be driven unstable by the nonlinear coupling. The general theory is then applied to the relativistic modulational instability of two laser beams in a beat-wave accelerator. For parameters typical of a proposed beat-wave accelerator, this instability can seriously distort the incident laser pulse shapes on the particle-acceleration time scale, with detrimental consequences for particle acceleration

  13. Coupling constant in dispersive model

    Indian Academy of Sciences (India)

    Abstract. The average of the moments for event shapes in e+e− → hadrons within the con- text of next-to-leading order (NLO) perturbative QCD prediction in dispersive model is studied. Moments used in this article are 〈1 − T〉, 〈ρ〉, 〈BT〉 and 〈BW〉. We extract αs, the coupling con- stant in perturbative theory and α0 in the ...

  14. Scientific charge-coupled devices

    Science.gov (United States)

    Janesick, James R.; Elliott, Tom; Collins, Stewart; Blouke, Morley M.; Freeman, Jack

    1987-01-01

    The charge-coupled device dominates an ever-increasing variety of scientific imaging and spectroscopy applications. Recent experience indicates, however, that the full potential of CCD performance lies well beyond that realized in devices currently available.Test data suggest that major improvements are feasible in spectral response, charge collection, charge transfer, and readout noise. These properties, their measurement in existing CCDs, and their potential for future improvement are discussed in this paper.

  15. Primordial fluctuations from nonlinear couplings

    International Nuclear Information System (INIS)

    Calzetta, E.A.; Gonorazky, S.

    1997-01-01

    We study the spectrum of primordial fluctuations in theories where the inflaton field is nonlinearly coupled to massless fields and/or to itself. Conformally invariant theories generically predict a scale-invariant spectrum. Scales entering the theory through infrared divergences cause logarithmic corrections to the spectrum, tilting it towards the blue. We discuss in some detail whether these fluctuations are quantum or classical in nature. copyright 1997 The American Physical Society

  16. Electroweak couplings of the lepton

    Indian Academy of Sciences (India)

    of ττ7 production. are made possible by the fact that the weak charged current via which the decays has a handed О structure so that the essentially acts as its own polarimeter. A combination of all LEP electroweak data gives the results shown in figure 2a for the vector and axial vector coupling constants ЪР and Р to the.

  17. Cooling apparatus and couplings therefor

    Science.gov (United States)

    Lomax, Curtis; Webbon, Bruce

    1993-11-01

    A cooling apparatus includes a container filled with a quantity of coolant fluid initially cooled to a solid phase, a cooling loop disposed between a heat load and the container. A pump for circulating a quantity of the same type of coolant fluid in a liquid phase through the cooling loop, a pair of couplings for communicating the liquid phase coolant fluid into the container in a direct interface with the solid phase coolant fluid.

  18. Long range supergravity coupling strengths

    International Nuclear Information System (INIS)

    Kenyon, I.R.

    1991-01-01

    A limit of 2x10 -13 has recently been deduced for the fractional difference between the gravitational masses of the K 0 and anti K 0 mesons. This limit is applied here to put stringent limits on the strengths of the long range vector-scalar gravitational couplings envisaged in supergravity theories. A weaker limit is inferred from the general relativistic fit to the precession of the orbit of the pulsar PSR1913+16. (orig.)

  19. Conduction-coupled Tesla transformer.

    Science.gov (United States)

    Reed, J L

    2015-03-01

    A proof-of-principle Tesla transformer circuit is introduced. The new transformer exhibits the high voltage-high power output signal of shock-excited transformers. The circuit, with specification of proper circuit element values, is capable of obtaining extreme oscillatory voltages. The primary and secondary portions of the circuit communicate solely by conduction. The destructive arcing between the primary and secondary inductors in electromagnetically coupled transformers is ubiquitous. Flashover is eliminated in the new transformer as the high-voltage inductors do not interpenetrate and so do not possess an annular volume of electric field. The inductors are remote from one another. The high voltage secondary inductor is isolated in space, except for a base feed conductor, and obtains earth by its self-capacitance to the surroundings. Governing equations, for the ideal case of no damping, are developed from first principles. Experimental, theoretical, and circuit simulator data are presented for the new transformer. Commercial high-temperature superconductors are discussed as a means to eliminate the counter-intuitive damping due to small primary inductances in both the electromagnetic-coupled and new conduction-coupled transformers.

  20. Statefinder diagnostic for coupled quintessence

    International Nuclear Information System (INIS)

    Zhang Xin

    2005-01-01

    The problem of the cosmic coincidence is a longstanding puzzle. This conundrum may be solved by introducing a coupling between the two dark sectors. In this Letter, we study two cases of the coupled quintessence scenario. (a) Assume that the mass of dark matter particles depends exponentially on the scalar field associated to dark energy and meanwhile the scalar field evolves in an exponential potential; (b) Assume that the mass of dark matter particles depends on a power law function of the scalar field and meanwhile the scalar field evolves in a power law potential. Since the dynamics of this system is dominated by an attractor solution, the mass of dark matter particles is forced to change with time as to ensure that the ratio between the energy densities of dark matter and dark energy becomes a constant at late times, and one thus solve the cosmic coincidence problem naturally. We perform a statefinder diagnostic to both cases of this coupled quintessence scenario. It is shown that the evolving trajectory of this scenario in the s-r diagram is quite different from those of other dark energy models

  1. Vibronic coupling in icosahedral systems

    CERN Document Server

    Huang, R

    2001-01-01

    consideration. In this thesis, an explanation based on the competition between the two tunneling paths on the lowest APES is proposed. It is assumed that tunneling occurs along paths of steepest descent. The reversal in sign of the tunneling splitting, calculated using the WKB method, in the icosahedral H x h Jahn-Teller system is explained in terms of different tunneling paths along which the system moves as the strength of the vibronic coupling K sub h sub sub 1 changes. It is found that this sign reversal occurs when K sub h sub sub 1 /(h/2 pi)w approx 4.1. This result is very near to the original result of K sub h sub sub 1 /(h/2 pi)w approx 3.8 obtained using a totally different method. This reversal can be explained as follows; for weak vibronic coupling, the H symmetry state is dominated by tunneling along the steepest descent path of C sub 1 symmetry which connects two D sub 3 sub d wells via one point on the D sub 3 symmetry saddle trough; for strong coupling, the A symmetry state is dominated by tun...

  2. Congruence Couple Therapy for Pathological Gambling

    Science.gov (United States)

    Lee, Bonnie K.

    2009-01-01

    Couple therapy models for pathological gambling are limited. Congruence Couple Therapy is an integrative, humanistic, systems model that addresses intrapsychic, interpersonal, intergenerational, and universal-spiritual disconnections of pathological gamblers and their spouses to shift towards congruence. Specifically, CCT's theoretical…

  3. Coupled seismic and electromagnetic wave propagation

    NARCIS (Netherlands)

    Schakel, M.D.

    2011-01-01

    Coupled seismic and electromagnetic wave propagation is studied theoretically and experimentally. This coupling arises because of the electrochemical double layer, which exists along the solid-grain/fluid-electrolyte boundaries of porous media. Within the double layer, charge is redistributed,

  4. The couple as context: Latino gay male couples and HIV.

    Science.gov (United States)

    Beougher, Sean C; Gomez, Walter; Hoff, Colleen C

    2011-03-01

    HIV-prevention efforts with gay men in relationships frequently omit primary partners. When they are considered, examinations of race/ethnicity are often overlooked despite higher infection rates among gay men of colour. Acknowledging both the need to contextualise the behaviours that may affect HIV risk for gay men of colour and the disproportionate impact of HIV on Latino gay men, the present study utilised semi-structured, qualitative interviews to explore relationship dynamics, sexual agreements and behaviours, safer sex choices and HIV risk among nine Latino gay male couples. All participants were HIV-negative and in concordant negative relationships. Additionally, nearly all reported closed agreements. Analysis revealed participants engaging in four behaviours that may actively reduce their HIV risk: approaching sexual agreements from a practical standpoint, maintaining a high literacy around HIV, having exposure to social support groups for Latino gay men and finding support in their relationship with another Latino gay man. Additional issues are raised where long-term HIV prevention is concerned. Intimate relationships are an important context for understanding both HIV risk and prevention among Latino gay men. Likewise, race/ethnicity provides an indispensable perspective on all research with gay couples. Future prevention efforts with gay men must strive to include both.

  5. Coordinate Mastering Using Optical Coupling

    Science.gov (United States)

    Bieman, Leonard H.

    1989-01-01

    For a multi-sensor machine vision system, relating each sensor's measurement to a master gage coordinate system has been a difficult task. This is especially true for sheet metal gaging in the automotive industry where sensors may be separated by four or five meters. The current approach used to establish this master coordinate system, which is difficult at best, has been the following. First, the part is placed in the gage. The exact location, that is being measured by each sensor, is marked on the part. Then the marked part is transported to a coordinate measuring machine (CMM), where the location of each of the marked points is measured. These CMM measurements establish a master coordinate system. The procedure just described has major drawbacks including: the accuracy of marking the exact location being measured; the sensors orientation must be known with respect to the master coordinate system; and deformation of the sheet metal part when it is transported to the CMM. The mastering process can be significantly improved by optical coupling a theodolite pair with each machine vision sensor. This optical coupling is established by locating a target in a position that can be accurately measured by both a sensor and the theodolite system. First, the theodolite system is calibrated in gage coordinates by sighting on reference points placed on the machine vision gage. Then, for each sensor, the target location is measured by both the sensor and theodolite pair at three or more positions (or alternately one target may have three or more points that can be measured). From this data, the transforms from sensor coordinates to gage coordinates can be calculated. This report will present the configuration and calculations for coordinate mastering using optical coupling.

  6. Spatiotemporal complexity in coupled map lattices

    International Nuclear Information System (INIS)

    Kaneko, Kunihiko

    1986-01-01

    Some spatiotemporal patterns of couple map lattices are presented. The chaotic kink-like motions are shown for the phase motion of the coupled circle lattices. An extension of the couple map lattice approach to Hamiltonian dynamics is briefly reported. An attempt to characterize the high-dimensional attractor by the extension of the correlation dimension is discussed. (author)

  7. Magnetically Coupled Magnet-Spring Oscillators

    Science.gov (United States)

    Donoso, G.; Ladera, C. L.; Martin, P.

    2010-01-01

    A system of two magnets hung from two vertical springs and oscillating in the hollows of a pair of coils connected in series is a new, interesting and useful example of coupled oscillators. The electromagnetically coupled oscillations of these oscillators are experimentally and theoretically studied. Its coupling is electromagnetic instead of…

  8. Electromagnetic Pulse Coupling Analysis of Electronic Equipment

    OpenAIRE

    Hong Lei; Qingying LI

    2017-01-01

    High-intensity nuclear explosion caused by high-altitude nuclear electromagnetic pulse through the antenna, metal cables, holes and other channels, coupled with very high energy into the electronic device, and cause serious threats. In this paper, the mechanism, waveform, coupling path and damage effect of nuclear electromagnetic pulse is analyzed, and the coupling mechanism of nuclear electromagnetic pulse is studied.

  9. Palladium-catalyzed coupling reactions

    CERN Document Server

    Molnár, Árpád

    2013-01-01

    This handbook and ready reference brings together all significant issues of practical importance for interested readers in one single volume. While covering homogeneous and heterogeneous catalysis, the text is unique in focusing on such important aspects as using different reaction media, microwave techniques or catalyst recycling. It also provides a comprehensive treatment of modern-day coupling reactions and emphasizes those topics that show potential for future development, such as continuous flow systems, water as a reaction medium, and catalyst immobilization, among others. With i

  10. Lectures on the coupling method

    CERN Document Server

    Lindvall, Torgny

    2002-01-01

    An important tool in probability theory and its applications, the coupling method is primarily used in estimates of total variation distances. The method also works well in establishing inequalities, and it has proven highly successful in the study of Markov and renewal process asymptotics. This text represents a detailed, comprehensive examination of the method and its broad variety of applications. Readers progress from simple to advanced topics, with end-of-discussion notes that reinforce the preceding material. Topics include renewal theory, Markov chains, Poisson approximation, ergodicity

  11. On the disordered fermion couplings

    International Nuclear Information System (INIS)

    Bernaschi, M.; Cabasino, S.; Marinari, E.; Rome-2 Univ.; Sarno, R.; Rome-1 Univ.

    1989-01-01

    We study the possibility of avoiding the fermion doubling problem by using a random coupling. We use numerical simulations in order to study the theory in the strong disorder region. We find a sharp crossover as a function of the strength of the disorder. For weak quenched disorder we find that the species doubling survives, while for strong quenched disorder only with a particular choice of the random term (antihermitian) it is possible to get a theory that seems to avoid fermion doubling. (orig.)

  12. Optical coupling in the ETEM

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Cavalca, Filippo Carlo; Damsgaard, Christian Danvad

    as a gaseous environment. By adding optical coupling to the transmission electron microscope (TEM) it is possible to gain insight in the fundamentals of their reaction mechanisms, chemical behavior, structure and morphology before, during and after reaction using in situ investigations. Typically...... of various photoreactive materials and structures. Novel information on the behavior of such materials during reaction was acquired in a reproducible fashion. In a wider perspective, the aim is to build a versatile experimental platform inside the microscope that allows electron microscopy under...

  13. Can coupling constants be related

    International Nuclear Information System (INIS)

    Nandi, Satyanarayan; Ng, Wing-Chiu.

    1978-06-01

    We analyze the conditions under which several coupling constants in field theory can be related to each other. When the relation is independent of the renormalization point, the relation between any g and g' must satisfy a differential equation as follows from the renormalization group equations. Using this differential equation, we investigate the criteria for the feasibility of a power-series relation for various theories, especially the Weinberg-Salam type (including Higgs bosons) with an arbitrary number of quark and lepton flavors. (orig./WL) [de

  14. EPR of exchange coupled systems

    CERN Document Server

    Bencini, Alessandro

    2012-01-01

    From chemistry to solid state physics to biology, the applications of Electron Paramagnetic Resonance (EPR) are relevant to many areas. This unified treatment is based on the spin Hamiltonian approach and makes extensive use of irreducible tensor techniques to analyze systems in which two or more spins are magnetically coupled. This edition contains a new Introduction by coauthor Dante Gatteschi, a pioneer and scholar of molecular magnetism.The first two chapters review the foundations of exchange interactions, followed by examinations of the spectra of pairs and clusters, relaxation in oligon

  15. Acoustic metamaterials with synergetic coupling

    Science.gov (United States)

    Ma, Fuyin; Huang, Meng; Wu, Jiu Hui

    2017-12-01

    In this paper, we propose a general design concept for acoustic metamaterials that introduces a ubiquitous synergetic behavior into the design procedure, in which the structure of the design is driven by its functional requirements. Since the physical properties of the widely used, resonant-type metamaterials are mainly determined by the eigenmodes of the structure, we first introduce the design concept through the modal displacement distributions on two typical plate-type structures. Next, by employing broadband sound attenuations that involve both the insulation and absorption as the typical targets, two synergetic coupling behaviors are systematically revealed among the dense resonant modes and multi-cell. Furthermore, through plate-type multiple-cell structures assembled from nine oscillators, the design is shown to realize strong broadband attenuations with either the average sound transmission loss (STL) below 2000 Hz higher than 40 dB or the absorption approximately 0.99 in the range of 400-700 Hz wherein the average absorption below 800 Hz remains higher than 0.8. Finally, two multi-cell plate-type samples are fabricated and then used experimentally to measure the STLs in support of the proposed synergetic coupling design method. Both the computational and experimental results demonstrate that the proposed synergetic design concept could effectively initiate a design for metamaterials that offer a new degree of freedom for broadband sound attenuations.

  16. Dynamics of coupled phantom and tachyon fields

    Energy Technology Data Exchange (ETDEWEB)

    Shahalam, M. [Zhejiang University of Technology, Institute for Advanced Physics and Mathematics, Hangzhou (China); Pathak, S.D.; Li, Shiyuan [Shandong University, School of Physics, Jinan (China); Myrzakulov, R. [Eurasian National University, Department of General and Theoretical Physics, Eurasian International Center for Theoretical Physics, Astana (Kazakhstan); Wang, Anzhong [Zhejiang University of Technology, Institute for Advanced Physics and Mathematics, Hangzhou (China); Baylor University, Department of Physics, GCAP-CASPER, Waco, TX (United States)

    2017-10-15

    In this paper, we apply the dynamical analysis to a coupled phantom field with scaling potential taking particular forms of the coupling (linear and combination of linear), and present phase space analysis. We investigate if there exists a late time accelerated scaling attractor that has the ratio of dark energy and dark matter densities of the order one. We observe that the scrutinized couplings cannot alleviate the coincidence problem, however, they acquire stable late time accelerated solutions. We also discuss a coupled tachyon field with inverse square potential assuming linear coupling. (orig.)

  17. Resonant coupling applied to superconducting accelerator structures

    International Nuclear Information System (INIS)

    Potter, James M.; Krawczyk, Frank L.

    2013-01-01

    The concept of resonant coupling and the benefits that accrue from its application is well known in the world of room temperature coupled cavity linacs. Design studies show that it can be applied successfully between sections of conventional elliptical superconducting coupled cavity accelerator structures and internally to structures with spoked cavity resonators. The coupling mechanisms can be designed without creating problems with high field regions or multipactoring. The application of resonant coupling to superconducting accelerators eliminates the need for complex cryogenic mechanical tuners and reduces the time needed to bring a superconducting accelerator into operation.

  18. The SUSY-QCD coupling relation

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, A.; /Zurich U.; Skands, P.Z.; /Fermilab

    2006-10-01

    In order to establish supersymmetry at future colliders, it is not sufficient to discover new particles, but the identity of gauge couplings and the corresponding Yukawa couplings between gauginos, sfermions and fermions needs to be verified. In detailed studies it was found that the SUSY-Yukawa couplings of the electroweak sector can be studied with great precision at the ILC, but a similar analysis for the Yukawa coupling of the SUSY-QCD sector proves to be far more challenging. Here a first phenomenological study for determining this coupling is presented, using a method which combines information from LHC and ILC.

  19. Enhanced prenatal HIV couple oriented counselling session and couple communication about HIV (ANRS 12127 Prenahtest Trial)

    NARCIS (Netherlands)

    Plazy, M.; Orne-Gliemann, J.; Balestre, E.; Miric, M.; Darak, S.; Butsashvili, M.; Tchendjou, P.; Dabis, F.; du Lou, A. Desgrees

    Background. - The Prenahtest study investigated the efficacy of a couple-oriented HIV counselling session (COC) in encouraging couple HIV counselling and testing, and improving intra-couple communication about sexual and reproductive health. We report here on the effect of COC on intra-couple

  20. Job Burnout and Couple Burnout in Dual-Earner Couples in the Sandwiched Generation

    Science.gov (United States)

    Pines, Ayala Malach; Neal, Margaret B.; Hammer, Leslie B.; Icekson, Tamar

    2011-01-01

    We use existential theory as a framework to explore the levels of and relationship between job and couple burnout reported by dual-earner couples in the "sandwich generation" (i.e., couples caring both for children and aging parents) in a sample of such couples in Israel and the United States. This comparison enables an examination of…

  1. Couple Support Schemata in Couples with and without Spinal Cord Injury

    Science.gov (United States)

    Gilad, Dvorit; Lavee, Yoav

    2010-01-01

    This article describes the cognitive schemata of couples' support relationships among 65 couples in which the husband had a long-term spinal cord injury and 65 couples without disability. The structure of the support relations schemata were examined by means of smallest-space analysis. Similarities between men and women in couples with and without…

  2. Clinical processes in behavioral couples therapy.

    Science.gov (United States)

    Fischer, Daniel J; Fink, Brandi C

    2014-03-01

    Behavioral couples therapy is a broad term for couples therapies that use behavioral techniques based on principles of operant conditioning, such as reinforcement. Behavioral shaping and rehearsal and acceptance are clinical processes found across contemporary behavioral couples therapies. These clinical processes are useful for assessment and case formulation, as well as teaching couples new methods of conflict resolution. Although these clinical processes assist therapists in achieving efficient and effective therapeutic change with distressed couples by rapidly stemming couples' corrosive affective exchanges, they also address the thoughts, emotions, and issues of trust and intimacy that are important aspects of the human experience in the context of a couple. Vignettes are provided to illustrate the clinical processes described. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  3. Coherence Phenomena in Coupled Optical Resonators

    Science.gov (United States)

    Smith, D. D.; Chang, H.

    2004-01-01

    We predict a variety of photonic coherence phenomena in passive and active coupled ring resonators. Specifically, the effective dispersive and absorptive steady-state response of coupled resonators is derived, and used to determine the conditions for coupled-resonator-induced transparency and absorption, lasing without gain, and cooperative cavity emission. These effects rely on coherent photon trapping, in direct analogy with coherent population trapping phenomena in atomic systems. We also demonstrate that the coupled-mode equations are formally identical to the two-level atom Schrodinger equation in the rotating-wave approximation, and use this result for the analysis of coupled-resonator photon dynamics. Notably, because these effects are predicted directly from coupled-mode theory, they are not unique to atoms, but rather are fundamental to systems of coherently coupled resonators.

  4. Physics of Strongly Coupled Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kraeft, Wolf-Dietrich [Universitat Rostock (Germany)

    2007-07-15

    Strongly coupled plasmas (or non-ideal plasmas) are multi-component charged many-particle systems, in which the mean value of the potential energy of the system is of the same order as or even higher than the mean value of the kinetic energy. The constituents are electrons, ions, atoms and molecules. Dusty (or complex) plasmas contain still mesoscopic (multiply charged) particles. In such systems, the effects of strong coupling (non-ideality) lead to considerable deviations of physical properties from the corresponding properties of ideal plasmas, i.e., of plasmas in which the mean kinetic energy is essentially larger than the mean potential energy. For instance, bound state energies become density dependent and vanish at higher densities (Mott effect) due to the interaction of the pair with the surrounding particles. Non-ideal plasmas are of interest both for general scientific reasons (including, for example, astrophysical questions), and for technical applications such as inertially confined fusion. In spite of great efforts both experimentally and theoretically, satisfactory information on the physical properties of strongly coupled plasmas is not at hand for any temperature and density. For example, the theoretical description of non-ideal plasmas is possible only at low densities/high temperatures and at extremely high densities (high degeneracy). For intermediate degeneracy, however, numerical experiments have to fill the gap. Experiments are difficult in the region of 'warm dense matter'. The monograph tries to present the state of the art concerning both theoretical and experimental attempts. It mainly includes results of the work performed in famous Russian laboratories in recent decades. After outlining basic concepts (chapter 1), the generation of plasmas is considered (chapter 2, chapter 3). Questions of partial (chapter 4) and full ionization (chapter 5) are discussed including Mott transition and Wigner crystallization. Electrical and

  5. Strongly coupled dust coulomb clusters

    International Nuclear Information System (INIS)

    Juan Wentau; Lai Yingju; Chen Mingheng; I Lin

    1999-01-01

    The structures and motions of quasi-2-dimensional strongly coupled dust Coulomb clusters with particle number N from few to hundreds in a cylindrical rf plasma trap are studied and compared with the results from the molecular dynamic simulation using more ideal models. Shell structures with periodic packing in different shells and intershell rotational motion dominated excitations are observed at small N. As N increases, the boundary has less effect, the system recovers to the triangular lattice with isotropic vortex type cooperative excitations similar to an infinite N system except the outer shell region. The above generic behaviors are mainly determined by the system symmetry and agree with the simulation results. The detailed interaction form causes minor effect such as the fine structure of packing

  6. Welding shield for coupling heaters

    Science.gov (United States)

    Menotti, James Louis

    2010-03-09

    Systems for coupling end portions of two elongated heater portions and methods of using such systems to treat a subsurface formation are described herein. A system may include a holding system configured to hold end portions of the two elongated heater portions so that the end portions are abutted together or located near each other; a shield for enclosing the end portions, and one or more inert gas inlets configured to provide at least one inert gas to flush the system with inert gas during welding of the end portions. The shield may be configured to inhibit oxidation during welding that joins the end portions together. The shield may include a hinged door that, when closed, is configured to at least partially isolate the interior of the shield from the atmosphere. The hinged door, when open, is configured to allow access to the interior of the shield.

  7. Phenomenology of coupled nonlinear oscillators

    Science.gov (United States)

    Estevez-Rams, E.; Estevez-Moya, D.; Aragón-Fernández, B.

    2018-02-01

    A recently introduced model of coupled nonlinear oscillators in a ring is revisited in terms of its information processing capabilities. The use of Lempel-Ziv based entropic measures allows to study thoroughly the complex patterns appearing in the system for different values of the control parameters. Such behaviors, resembling cellular automata, have been characterized both spatially and temporally. Information distance is used to study the stability of the system to perturbations in the initial conditions and in the control parameters. The latter is not an issue in cellular automata theory, where the rules form a numerable set, contrary to the continuous nature of the parameter space in the system studied in this contribution. The variation in the density of the digits, as a function of time is also studied. Local transitions in the control parameter space are also discussed.

  8. Capacitively-coupled chopper amplifiers

    CERN Document Server

    Fan, Qinwen; Huijsing, Johan H

    2017-01-01

    This book describes the concept and design of the capacitively-coupled chopper technique, which can be used in precision analog amplifiers. Readers will learn to design power-efficient amplifiers employing this technique, which can be powered by regular low supply voltage such as 2V and possibly having a +\\-100V input common-mode voltage input. The authors provide both basic design concepts and detailed design examples, which cover the area of both operational and instrumentation amplifiers for multiple applications, particularly in power management and biomedical circuit designs. Discusses basic working principles and details of implementation for proven designs; Includes a diverse set of applications, along with measurement results to demonstrate the effectiveness of the technique; Explains advantages and drawbacks of the technique, given particular circumstances.

  9. Seismic coupling of nuclear explosions

    International Nuclear Information System (INIS)

    Larson, D.B.

    1989-01-01

    The new Giant Magnet Experimental Facility employing digital recording of explosion induced motion has been constructed and successfully tested. Particle velocity and piezoresistance gage responses can be measured simultaneously thus providing the capability for determining the multi-component stress-strain history in the test material. This capability provides the information necessary for validation of computer models used in simulation of nuclear underground testing, chemical explosion testing, dynamic structural response, earth penetration response, and etc. This report discusses fully coupled and cavity decoupled explosions of the same energy (0.622 kJ) were carried out as experiments to study wave propagation and attenuation in polymethylmethacrylate (PMMA). These experiments produced particle velocity time histories at strains from 2 x 10 -3 to as low as 5.8 x 10 -6 . Other experiments in PMMA, reported recently by Stout and Larson 8 provide additional particle velocity data to strains of 10 -1

  10. Invasive tightly coupled processor arrays

    CERN Document Server

    LARI, VAHID

    2016-01-01

    This book introduces new massively parallel computer (MPSoC) architectures called invasive tightly coupled processor arrays. It proposes strategies, architecture designs, and programming interfaces for invasive TCPAs that allow invading and subsequently executing loop programs with strict requirements or guarantees of non-functional execution qualities such as performance, power consumption, and reliability. For the first time, such a configurable processor array architecture consisting of locally interconnected VLIW processing elements can be claimed by programs, either in full or in part, using the principle of invasive computing. Invasive TCPAs provide unprecedented energy efficiency for the parallel execution of nested loop programs by avoiding any global memory access such as GPUs and may even support loops with complex dependencies such as loop-carried dependencies that are not amenable to parallel execution on GPUs. For this purpose, the book proposes different invasion strategies for claiming a desire...

  11. Couples' fertility decision-making

    Directory of Open Access Journals (Sweden)

    Petra Stein

    2014-06-01

    Full Text Available Background: The decision about whether to start a family within a partnership can be viewed as a result of an interaction process. The influence of each of the partners in a couple differs depending on their individual preferences and intentions towards having children. Both of the partners additionally influence each other's fertility intentions and preferences. Objective: We specify, estimate, and test a model that examines the decision about whether to have a child as a choice that is made jointly by the two partners. The transition to the birth of a (further child is investigated with the explicit consideration of both the female partner and the male partner in the partnership context. Methods: An approach for modelling the interactive influences of the two actors in the decision-making process was proposed. A trivariate distribution consisting of both the female and the male partners' fertility intentions, as well as the joint generative decision, was modelled. A multivariate non-linear probit model was chosen and the problem of identification in estimating the relative effects of the actors was resolved. These parameters were used to assess the relative importance of each of the partners' intentions in the decision. We carried out the analysis with MPLUS. Data from the panel of intimate relationships and family dynamics (pairfam was used to estimate the model. Results: The biographical context of each of the partners in relation to their own as well as to their partner's fertility intentions was found to be of considerable importance. Of the significant individual and partner effects, the male partner was shown to have the greater influence. But the female partner was found to have stronger parameters overall and she ultimately has a veto power in the couple's final decision.

  12. Fluid-structure thermal coupling

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, J. [Adtech, N3S, Tokyo (Japan); Gasser, D. [Simulog, N3S, Estet, Simail, 78 - Saint Quentin en Yvelyne (France)

    1997-12-31

    On many occasions thermal exchange takes place between a structure and a fluid flowing in its neighbourhood. Such phenomena can be very complex, and numerical simulation is then an interesting means to understand them better. In that context, SIMULOG simulated the air flow around a radiator using the coupled numerical codes N3S and SYRTHES, which are developed at EDF/LNH. While N3S computes the air flow and thermal convection around the radiator`s fins, SYRTHES computes heat conduction in the radiator. The N3S-SYRTHES coupling process takes into account the heat transfer at the fluid/solid interface. Two computations were performed, corresponding to air flow rates values between the fins of 0.0518 m{sup 3}/s and 0.0865 m{sup 3}/s, and a radiator temperature of 40 deg C, the air flows along the Z axis from the bottom to the top of the radiator. A rise in temperature, along the Z axis, takes place in the air and in the radiator. The maximum temperature reached inside the radiator is 55 deg C for the lowest flow and 51 deg C for the highest one. The average decrease of the air and radiator temperature is about 5 deg C when the flow rate raises from 0.0518 m{sup 3}/s to 0.0865 m{sup 3}/s. Such a simulation gives important information for the conception and the performance evaluation of this process where the main objective is to control the maximum temperature. (authors)

  13. Optimization of mixed quantum-classical dynamics: Time-derivative coupling terms and selected couplings

    International Nuclear Information System (INIS)

    Pittner, Jiri; Lischka, Hans; Barbatti, Mario

    2009-01-01

    The usage of time-derivative non-adiabatic coupling terms and partially coupled time-dependent equations are investigated to accelerate non-adiabatic dynamics simulations at multireference configuration interaction (MRCI) level. The quality of the results and computational costs are compared against non-adiabatic benchmark dynamics calculations using non-adiabatic coupling vectors. In the comparison between the time-derivative couplings and coupling vectors, deviations in the adiabatic population of individual trajectories were observed in regions of rapid variation of the coupling terms. They, however, affected the average adiabatic population to only about 5%. For small multiconfiguration spaces, dynamics with time-derivative couplings are significantly faster than those with coupling vectors. This relation inverts for larger configuration spaces. The use of the partially coupled equations approach speeds up the simulations significantly while keeping the deviations in the population below few percent. Imidazole and the methaniminium cation are used as test examples

  14. Couples coping with discordant HIV status.

    Science.gov (United States)

    Beckerman, Nancy L

    2002-02-01

    As we start the third decade of the human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic, how does HIV/AIDS affect the emotional lives of couples of mixed HIV status? This is a case report based on the findings of an exploratory research study of serodiscordant couples in the New York City area. It focuses on the issues confronting a particular couple who represent the salient issues in the lives of serodiscordant couples. This case report discusses the findings of a study that attempted to ascertain the central emotional challenges facing couples of mixed HIV status and discusses one case in particular that illustrates how these issues might commonly manifest themselves. Fear of HIV transmission, coping with uncertainty of potential illness, shifts in emotional intimacy, and dilemmas regarding how HIV has impacted reproductive alternatives were identified as the most commonly experienced emotional issues for the serodiscordant couple.

  15. Infidelity in couples seeking marital therapy.

    Science.gov (United States)

    Atkins, David C; Yi, Jean; Baucom, Donald H; Christensen, Andrew

    2005-09-01

    The revelation of an affair is often an emotionally explosive event for a couple, yet little is known about specific individual and relationship factors that accompany infidelity. The present study examined the qualities of individuals and couples that differentiate couples with (n = 19) and without (n = 115) infidelity using couples from a randomized clinical trial of marital therapy. Findings indicated that couples with infidelity showed greater marital instability, dishonesty, arguments about trust, narcissism, and time spent apart. Gender also proved to be a significant moderator of several effects. Men who had participated in affairs showed increased substance use, were older, and were more sexually dissatisfied. Results offer initial clues to concomitants of affairs for couple therapists. (c) 2005 APA, all rights reserved

  16. COUPLING MEASUREMENT AND CORRECTION AT RHIC

    International Nuclear Information System (INIS)

    PILAT, F.; BEEBE-WANG, J.; FISCHER, W.; PTITSYN, V.; SATOGATA, T.

    2002-01-01

    Coupling correction at RHIC has been operationally achieved through a two-step process: using local triplet skew quadrupoles to compensate coupling corn rolled low-beta triplet quadrupoles, and minimizing the tune separation and residual coupling with orthogonal global skew quadrupole families. An application has been developed for global correction that allows skew quadrupole tuning and tune display with a choice of different tune measurement techniques, including tune-meter, Schottky and phase lock loop (PLL). Coupling effects have been analyzed by using 1024-turn (TBT) information from the beam position monitor (BPM) system. These data allow the reconstruction of the off-diagonal terms of the transfer matrix, a measure of global coupling. At both injection and storage energies, coordination of tune meter kicks with TBT acquisition at 322 BPW's in each ring allows the measurement of local coupling at all BPM locations

  17. Magnetosphere - Ionosphere - Thermosphere (MIT) Coupling at Jupiter

    Science.gov (United States)

    Yates, J. N.; Ray, L. C.; Achilleos, N.

    2017-12-01

    Jupiter's upper atmospheric temperature is considerably higher than that predicted by Solar Extreme Ultraviolet (EUV) heating alone. Simulations incorporating magnetosphere-ionosphere coupling effects into general circulation models have, to date, struggled to reproduce the observed atmospheric temperatures under simplifying assumptions such as azimuthal symmetry and a spin-aligned dipole magnetic field. Here we present the development of a full three-dimensional thermosphere model coupled in both hemispheres to an axisymmetric magnetosphere model. This new coupled model is based on the two-dimensional MIT model presented in Yates et al., 2014. This coupled model is a critical step towards to the development of a fully coupled 3D MIT model. We discuss and compare the resulting thermospheric flows, energy balance and MI coupling currents to those presented in previous 2D MIT models.

  18. Phenomenology of microwave coupling, part 1

    Science.gov (United States)

    King, R. J.; Breakall, J. K.; Hudson, H. G.; Morrison, J. J.; McGevna, V. G.; Kunz, K. S.; Ludwigsen, A. P.; Gnade, D. K.

    1984-11-01

    Advances in the development of high power microwave sources have increased the potential for future deployment of microwave weapons. A key ingredient in being able to predict the vulnerability of military systems to such threats involves understanding the phenomenology of how electromagnetic energy couples into cavity like objects, or the so called back door coupling. A similar but much longer standing problem is that of nuclear electromagnetic pulses (EMP) in which the frequencies extend up to several hundreds of MHz. However, compared to EMP coupling, microwave coupling is distinctively different because the wavelength is comparable to the size of the ports of entry. Coupling paths can be highly resonant at certain microwave frequencies, making the shielding against microwave threats difficult. The initial efforts at Lawrence Livermore National Laboratory to study the phenomenology of back door coupling at the low microwave frequencies (up to 2.5 GHz) are summarized.

  19. On the evanescence of contemporary couples

    Directory of Open Access Journals (Sweden)

    Luigi D'Elia

    2014-09-01

    Full Text Available This work analyses some recent difficulties faced by individuals when they start to get together as a couple and then when they remain together over time, in the background of social changes in recent decades. These difficulties are explained through the construct of dis- perception, which indicates those prevailing and misleading social representations that individuals use to design and live a couple life, but run into the ambiguity and impasse. Finally, the author formulates some hypotheses about the current difficulty in constructing a couple that causes the evanescence of contemporary couples, and he hints at new structure related and consistent systems of care.Keywords: Problematic constructing of the contemporary couple; dis-perception; Fading of the couple; Generative distress; Family planning sine die; Therapy as a procedural and symbolic-cultural support

  20. Extracting Higgs boson couplings from LHC data

    CERN Document Server

    Dührssen, M; Logan, H; Rainwater, D L; Weiglein, Georg; Zeppenfeld, Dieter

    2004-01-01

    We show how LHC Higgs boson production and decay data can be used to extract gauge and fermion couplings of Higgs bosons. We show that very mild theoretical assumptions, which are valid in general multi-Higgs doublet models, are sufficient to allow the extraction of absolute values for the couplings rather than just ratios of the couplings. For Higgs masses below 200 GeV we find accuracies of 10-40% for the Higgs boson couplings and total width after several years of LHC running. Slightly stronger assumptions on the Higgs gauge couplings even lead to a determination of couplings to fermions at the level of 10-20%. We also study the sensitivity to deviations from SM predictions in several supersymmetric benchmark scenarios as a subset of the analysis.

  1. Coupled cellular automata for frozen soil processes

    OpenAIRE

    R. M. Nagare; P. Bhattacharya; J. Khanna; R. A. Schincariol

    2015-01-01

    Heat and water movement in variably saturated freezing soils is a strongly coupled phenomenon. The coupling is a result of the effects of sub-zero temperature on soil water potential, heat carried by water moving under pressure gradients, and dependency of soil thermal and hydraulic properties on soil water content. This study presents a one-dimensional cellular automata (direct solving) model to simulate coupled heat and water transport with phase change in variably satura...

  2. Improved formalism for precision Higgs coupling fits

    International Nuclear Information System (INIS)

    Barklow, Tim; Peskin, Michael E.; Jung, Sunghoon; Tian, Junping

    2017-08-01

    Future e + e - colliders give the promise of model-independent determinations of the couplings of the Higgs boson. In this paper, we present an improved formalism for extracting Higgs boson couplings from e + e - data, based on the Effective Field Theory description of corrections to the Standard Model. We apply this formalism to give projections of Higgs coupling accuracies for stages of the International Linear Collider and for other proposed e + e - colliders.

  3. How initial representations shape coupled learning processes

    DEFF Research Database (Denmark)

    Puranam, Phanish; Swamy, M.

    2016-01-01

    Coupled learning processes, in which specialists from different domains learn how to make interdependent choices among alternatives, are common in organizations. We explore the role played by initial representations held by the learners in coupled learning processes using a formal agent-based model...... one that does not discriminate among alternatives, or even a mix of correct and incorrect representations among the learners. We draw implications for the design of coupled learning processes in organizations. © 2016 INFORMS....

  4. Axial forces in centrifugal compressor couplings

    Science.gov (United States)

    Ivanov, A. N.; Ivanov, N. M.; Yun, V. K.

    2017-08-01

    The article presents the results of the theoretical and experimental investigation of axial forces arising in the toothed and plate couplings of centrifugal compressor shaft lines. Additional loads on the thrust bearing are considered that can develop in the toothed couplings as a result of coupled rotors misalignment. Design relationships to evaluate the level of axial forces and recommendations for their reduction in the operating conditions are given.

  5. Improved formalism for precision Higgs coupling fits

    Science.gov (United States)

    Barklow, Tim; Fujii, Keisuke; Jung, Sunghoon; Karl, Robert; List, Jenny; Ogawa, Tomohisa; Peskin, Michael E.; Tian, Junping

    2018-03-01

    Future e+e- colliders give the promise of model-independent determinations of the couplings of the Higgs boson. In this paper, we present an improved formalism for extracting Higgs boson couplings from e+e- data, based on the effective field theory description of corrections to the Standard Model. We apply this formalism to give projections of Higgs coupling accuracies for stages of the International Linear Collider and for other proposed e+e- colliders.

  6. Hadronic couplings of open beauty states

    International Nuclear Information System (INIS)

    Ram, S.N.; Singh, C.P.

    1982-08-01

    Strong interaction coupling parameters of particles with beauty quantum number are obtained using dispersion sum rules in various forms, e.g. current algebra sum rules, superconvergence sum rules and finite energy sum rules etc. These sum rules lead to a set of algebraic relations among masses and coupling constants. We compare the hadronic couplings of beautiful particles as obtained from various techniques and discuss their implications on the hadronic production of these states. (author)

  7. Synchronous Behavior of Two Coupled Biological Neurons

    International Nuclear Information System (INIS)

    Elson, R.C.; Selverston, A.I.; Elson, R.C.; Selverston, A.I.; Huerta, R.; Rulkov, N.F.; Rabinovich, M.I.; Abarbanel, H.D.; Selverston, A.I.; Huerta, R.; Abarbanel, H.D.

    1998-01-01

    We report experimental studies of synchronization phenomena in a pair of biological neurons that interact through naturally occurring, electrical coupling. When these neurons generate irregular bursts of spikes, the natural coupling synchronizes slow oscillations of membrane potential, but not the fast spikes. By adding artificial electrical coupling we studied transitions between synchrony and asynchrony in both slow oscillations and fast spikes. We discuss the dynamics of bursting and synchronization in living neurons with distributed functional morphology. copyright 1998 The American Physical Society

  8. A Magnetically Coupled Cryogenic Pump

    Science.gov (United States)

    Hatfield, Walter; Jumper, Kevin

    2011-01-01

    Historically, cryogenic pumps used for propellant loading at Kennedy Space Center (KSC) and other NASA Centers have a bellows mechanical seal and oil bath ball bearings, both of which can be problematic and require high maintenance. Because of the extremely low temperatures, the mechanical seals are made of special materials and design, have wearing surfaces, are subject to improper installation, and commonly are a potential leak path. The ball bearings are non-precision bearings [ABEC-1 (Annular Bearing Engineering Council)] and are lubricated using LOX compatible oil. This oil is compatible with the propellant to prevent explosions, but does not have good lubricating properties. Due to the poor lubricity, it has been a goal of the KSC cryogenics community for the last 15 years to develop a magnetically coupled pump, which would eliminate these two potential issues. A number of projects have been attempted, but none of the pumps was a success. An off-the-shelf magnetically coupled pump (typically used with corrosive fluids) was procured that has been used for hypergolic service at KSC. The KSC Cryogenics Test Lab (CTL) operated the pump in cryogenic LN2 as received to determine a baseline for modifications required. The pump bushing, bearings, and thrust rings failed, and the pump would not flow liquid (this is a typical failure mode that was experienced in the previous attempts). Using the knowledge gained over the years designing and building cryogenic pumps, the CTL determined alternative materials that would be suitable for use under the pump design conditions. The CTL procured alternative materials for the bearings (bronze, aluminum bronze, and glass filled PTFE) and machined new bearing bushings, sleeves, and thrust rings. The designed clearances among the bushings, sleeves, thrust rings, case, and case cover were altered once again using experience gained from previous cryogenic pump rebuilds and designs. The alternative material parts were assembled into

  9. RF and microwave coupled-line circuits

    CERN Document Server

    Mongia, R K; Bhartia, P; Hong, J; Gupta, K C

    2007-01-01

    This extensively revised edition of the 1999 Artech House classic, RF and Microwave Coupled-Line Circuits, offers you a thoroughly up-to-date understanding of coupled line fundamentals, explaining their applications in designing microwave and millimeter-wave components used in today's communications, microwave, and radar systems. The Second Edition includes a wealth of new material, particularly relating to applications. You find brand new discussions on a novel simple design technique for multilayer coupled circuits, high pass filters using coupled lines, software packages used for filter des

  10. Coupled ears in lizards and crocodilians

    DEFF Research Database (Denmark)

    Carr, Catherine E; Christensen-Dalsgaard, Jakob; Bierman, Hilary

    2016-01-01

    Lizard ears are coupled across the pharynx, and are very directional. In consequence all auditory responses should be directional, without a requirement for computation of sound source location. Crocodilian ears are connected through sinuses, and thus less tightly coupled. Coupling may improve...... the processing of low-frequency directional signals, while higher frequency signals appear to be progressively uncoupled. In both lizards and crocodilians, the increased directionality of the coupled ears leads to an effectively larger head and larger physiological range of ITDs. This increased physiological...

  11. Topology Optimisation for Coupled Convection Problems

    DEFF Research Database (Denmark)

    Alexandersen, Joe; Andreasen, Casper Schousboe; Aage, Niels

    stabilised finite elements implemented in a parallel multiphysics analysis and optimisation framework DFEM [1], developed and maintained in house. Focus is put on control of the temperature field within the solid structure and the problems can therefore be seen as conjugate heat transfer problems, where heat...... conduction governs in the solid parts of the design domain and couples to convection-dominated heat transfer to a surrounding fluid. Both loosely coupled and tightly coupled problems are considered. The loosely coupled problems are convection-diffusion problems, based on an advective velocity field from...

  12. Relationship Recognition Patterns of Same-sex Couples by Gender

    OpenAIRE

    Institute, Williams

    2014-01-01

    Female couples are more likely to formalize their relationships than male couples. Female couples account for just over half (51%) of all same-sex couples in the U.S. However, data from the state agencies show that 64% of same-sex couples who entered into legal statuses were female couples.

  13. Generalized N-coupled maps with invariant measure in Bose ...

    Indian Academy of Sciences (India)

    different coupled map matrices such as nearest neighbor coupled map, second near- est neighbor coupled map and globally coupled maps. Definition of the coupled map model based on the adjacency matrix allows us to use the spectrum of graph based on the associated scheme. Therefore, N-coupled map is defined as ...

  14. HOW CONTEXT AFFECTS COUPLE SATISFACTION?

    Directory of Open Access Journals (Sweden)

    Rozzana Sánchez-Aragón

    2012-12-01

    Full Text Available There are few studies that focus on the influence that contextual aspects have in marital satisfaction (Meléndez, Aleixandre,& Saez, 1993.However, nowadays the reasons for a divorce are related to the actual social situation (Khalfani-Cox, 2009. Thus, the aim of this study is to identify contextual aspects that are associ-ated with marital satisfaction; in order to accomplish this objective, we conducted two studies. The purpose of the first study was to identify recent context aspects that influence marital satisfaction throughout an open question, which was ap-plied to 131 people. The results indicate that the dimensions of economic, labor time, home safety, stress in the environment, and the place where they live influ-ence marital satisfaction. In the second study, based on the information obtained previously, we formed indicators that were applied together with a scale of mari-tal satisfaction to105 couples. The results show that the context is closely related to marital satisfaction. In addition, the results determine that men give greater importance to the economic and employment situation than women do. Overall, this study indicates that sex differences prove that the roles and cultural expecta-tions have remained in the dynamics of the relationship and thus influence the assessment of marital satisfaction.

  15. Intracellular Polyamines Enhance Astrocytic Coupling

    Science.gov (United States)

    Benedikt, Jan; Inyushin, Mikhail; Kucheryavykh, Yuriy V.; Rivera, Yomarie; Kucheryavykh, Lilia Y.; Nichols, Colin G.; Eaton, Misty J.; Skatchkov, Serguei N.

    2013-01-01

    Spermine (SPM) and spermidine (SPD), endogenous polyamines (PA) with the ability to modulate various ion channels and receptors in the brain, exert neuroprotective, antidepressant, antioxidant and other effects in vivo such as increasing longevity. These PA are preferably accumulated in astrocytes, and we hypothesized that SPM increases glial intercellular communication by interacting with glial gap junctions. Results obtained in situ, using Lucifer yellow propagation in the astrocytic syncitium of 21–25 day old rat CA1 hippocampal slices, showed reduced coupling when astrocytes were dialyzed with standard intracellular solutions (ICS) without SPM. However, there was a robust increase in the spreading of Lucifer yellow via gap junctions to neighboring astrocytes when the cells were patched with ICS containing 1 mM SPM; a physiological concentration in glia. Lucifer yellow propagation was inhibited by gap junction blockers. Our findings show that the glial syncitium propagates SPM via gap junctions and further suggest a new role of polyamines in the regulation of the astroglial network in both normal and pathological conditions. PMID:23076119

  16. Coupling of Plasmas and Liquids

    Science.gov (United States)

    Lindsay, Alexander David

    Plasma-liquids have exciting applications to several important socioeconomic areas, including agriculture, water treatment, and medicine. To realize their application potential, the basic physical and chemical phenomena of plasma-liquid systems must be better understood. Additionally, system designs must be optimized in order to maximize fluxes of critical plasma species to the liquid phase. With objectives to increase understanding of these systems and optimize their applications, we have performed both comprehensive modeling and experimental work. To date, models of plasma-liquids have focused on configurations where diffusion is the dominant transport process in both gas and liquid phases. However, convection plays a key role in many popular plasma source designs, including jets, corona discharges, and torches. In this dissertation, we model momentum, heat, and neutral species mass transfer in a convection-dominated system based on a corona discharge. We show that evaporative cooling produced by gas-phase convection can lead to a significant difference between gas and liquid phase bulk temperatures. Additionally, convection induced in the liquid phase by the gas phase flow substantially increases interfacial mass transfer of hydrophobic species like NO and NO2. Finally, liquid kinetic modeling suggests that concentrations of highly reactive species like OH and ONOOH are several orders of magnitude higher at the interface than in the solution bulk. Subsequent modeling has focused on coupling discharge physics with species transport at and through the interface. An assumption commonly seen in the literature is that interfacial loss coefficients of charged species like electrons are equal to unity. However, there is no experimental evidence to either deny or support this assumption. Without knowing the true interfacial behavior of electrons, we have explored the effects on key plasma-liquid variables of varying interfacial parameters like the electron and energy

  17. Neural Cross-Frequency Coupling Functions

    Directory of Open Access Journals (Sweden)

    Tomislav Stankovski

    2017-06-01

    Full Text Available Although neural interactions are usually characterized only by their coupling strength and directionality, there is often a need to go beyond this by establishing the functional mechanisms of the interaction. We introduce the use of dynamical Bayesian inference for estimation of the coupling functions of neural oscillations in the presence of noise. By grouping the partial functional contributions, the coupling is decomposed into its functional components and its most important characteristics—strength and form—are quantified. The method is applied to characterize the δ-to-α phase-to-phase neural coupling functions from electroencephalographic (EEG data of the human resting state, and the differences that arise when the eyes are either open (EO or closed (EC are evaluated. The δ-to-α phase-to-phase coupling functions were reconstructed, quantified, compared, and followed as they evolved in time. Using phase-shuffled surrogates to test for significance, we show how the strength of the direct coupling, and the similarity and variability of the coupling functions, characterize the EO and EC states for different regions of the brain. We confirm an earlier observation that the direct coupling is stronger during EC, and we show for the first time that the coupling function is significantly less variable. Given the current understanding of the effects of e.g., aging and dementia on δ-waves, as well as the effect of cognitive and emotional tasks on α-waves, one may expect that new insights into the neural mechanisms underlying certain diseases will be obtained from studies of coupling functions. In principle, any pair of coupled oscillations could be studied in the same way as those shown here.

  18. Subcycle Extreme Nonlinearities in GaP Induced by an Ultrastrong Terahertz Field

    Science.gov (United States)

    Vicario, Carlo; Shalaby, Mostafa; Hauri, Christoph P.

    2017-02-01

    We report on the experimental observation of extreme laser spectral broadening and a change in optical transmission in gallium phosphite induced by 25 MV /cm terahertz (THz) single-cycle internal field. Such intense THz radiation leads to twofold transient modifications of the optical properties in the electro-optical crystal. First, the electric field provokes extensive cross-phase modulation via the χ(2 ) and χ(3 ) nonlinearities on a copropagating 50 fs near infrared laser pulse which turns into 500% spectral broadening. Second, we observe an instantaneous change of the optical transmission occurring at the THz field which is alleged to interband Zener tunneling and charge carrier density modification by impact ionization turning the semiconductor in a metal-like transient state. The presented scheme displays a pathway to coherently control the optical properties of semiconductors on an ultrafast time scale by a strong THz field.

  19. Institute for Ultra-Strong Composites by Computational Design (US-COMP)

    Data.gov (United States)

    National Aeronautics and Space Administration — Affordable deep space exploration will require transformative materials for the manufacturing of next-generation transit vehicles, habitats, power systems, and other...

  20. Synchronization of indirectly coupled Lorenz oscillators: An ...

    Indian Academy of Sciences (India)

    E-mail: m.shrimali@gmail.com. Abstract. The dynamics of indirectly coupled Lorenz circuits is investigated experimentally. The in-phase and anti-phase synchronization of indirectly coupled chaotic oscillators reported in Phys. Rev. E 81, 046216 (2010) is verified by physical experiments with electronic circuits. Two chaotic.

  1. Compensation of coupling in the SSC complex

    International Nuclear Information System (INIS)

    Pilat, F.; Bourianoff, G.

    1991-10-01

    This paper will describe a study of the coupling effects and their compensation by means of local depending techniques for some of the accelerators in the SSC Complex. Results concerning corrections and decoupling for the Low Energy and Medium Energy Boosters will be compared to results obtained for the Collider Ring. Some preliminary experimental data about measurement of coupling quantities will also be presented

  2. Concentration inequalities for random fields via coupling

    NARCIS (Netherlands)

    Chazottes, J. R.; Collet, P.; Kuelske, C.; Redig, F.

    We present a new and simple approach to concentration inequalities in the context of dependent random processes and random fields. Our method is based on coupling and does not use information inequalities. In case one has a uniform control on the coupling, one obtains exponential concentration

  3. The Bushido Matrix for Couple Communication

    Science.gov (United States)

    Li, Chi-Sing; Lin, Yu-Fen; Ginsburg, Phil; Eckstein, Daniel

    2012-01-01

    The concept of Japanese Bushido and its seven virtues were introduced by the authors in this article for the practice and application of couple communication. The Bushido Matrix Worksheet (BMW) was created for enhancing couple's awareness and understanding of each other's values and experiences. An activity and a case study to demonstrate the use…

  4. Synchronization of coupled chaotic dynamics on networks

    Indian Academy of Sciences (India)

    We review some recent work on the synchronization of coupled dynamical systems on a variety of networks. When nodes show synchronized behaviour, two ... [5], congregations of synchronously flashing fireflies [6], and cricket that chirp in unison [7]. Coupled oscillators were first studied by Winfree [8] and Kuramoto [9].

  5. Dynamics of unidirectionally coupled bistable Henon maps

    International Nuclear Information System (INIS)

    Sausedo-Solorio, J.M.; Pisarchik, A.N.

    2011-01-01

    We study dynamics of two bistable Henon maps coupled in a master-slave configuration. In the case of coexistence of two periodic orbits, the slave map evolves into the master map state after transients, which duration determines synchronization time and obeys a -1/2 power law with respect to the coupling strength. This scaling law is almost independent of the map parameter. In the case of coexistence of chaotic and periodic attractors, very complex dynamics is observed, including the emergence of new attractors as the coupling strength is increased. The attractor of the master map always exists in the slave map independently of the coupling strength. For a high coupling strength, complete synchronization can be achieved only for the attractor similar to that of the master map. -- Highlights: → We study dynamics of two bistable Henon maps coupled in a master-slave configuration. → Synchronization time for periodic orbits obeys a -1/2 power law with respect to coupling. → For a high coupling strength, the slave map remains bistable. → Complete synchronization can be achieved only when both maps stay at the same attractor.

  6. Subfecundity in overweight and obese couples

    DEFF Research Database (Denmark)

    Ramlau-Hansen, C H; Thulstrup, A M; Bonde, J P

    2007-01-01

    BACKGROUND: Recent studies indicate that not only women's but also men's obesity has adverse effects on fecundity and since fecundity is a couple concept, we examined fecundity in relation to overweight and obesity of the couple. We also examined the association between weight changes and fecundity...

  7. Dual-Career Couples: Keeping Them Together.

    Science.gov (United States)

    Wolf-Wendel, Lisa E.; Twombly, Susan; Rice, Suzanne

    2000-01-01

    Reports results of a survey of 360 chief academic officers at member institutions of the American Association of Colleges and Universities regarding their policies and practices for assisting dual-career couples. Examines the motivations, barriers, consequences, and policy implications of institutional responses to dual-career couples. (DB)

  8. Compensation of oscillation coupling induced by solenoids

    International Nuclear Information System (INIS)

    Zelinskij, A.Yu.; Karnaukhov, I.M.; Shcherbakov, A.A.

    1988-01-01

    Methods for construction of various schemes of oscillation coupling compensation, induced by solenoids in charged particle storage rings, are described. Peculiarities of magnetic structure, enabling to localize oscillation coupling in wide energy range are discussed. Results of calculation of compensation schemes for design of NR-2000 storage ring spin rotation are presented

  9. Gauge coupling renormalization in Ads5

    Indian Academy of Sciences (India)

    2 action. We consider contributions from fields with arbitrary spins and arbitrary orbifold parities. For supersymmetric case, the calculation can be carried over in the framework of 4D low energy effective supergravity. The 1-loop gauge couplings can be determined by the loop-induced axion couplings and the tree level ...

  10. Narcissism and Intimacy: Treating the Wounded Couple.

    Science.gov (United States)

    Solomon, Marion F.

    1994-01-01

    Couples whose early wounds cause narcissistic and borderline defenses may benefit from treatment with a psychodynamically oriented couples therapist. This article presents a treatment method that helps partners become attuned to each other's underlying injuries and vulnerabilities. The goal is to rebuild damaged structures of the self and to…

  11. Generalized coupling in the Kuramoto model

    DEFF Research Database (Denmark)

    Filatrella, G.; Pedersen, Niels Falsig; Wiesenfeld, K.

    2007-01-01

    We propose a modification of the Kuramoto model to account for the effective change in the coupling constant among the oscillators, as suggested by some experiments on Josephson junction, laser arrays, and mechanical systems, where the active elements are turned on one by one. The resulting model...... with the behavior of Josephson junctions coupled via a cavity....

  12. Does coupling ofuterine contractions reflect uterine dysfunction?

    African Journals Online (AJOL)

    Abstract In a cohort analytical study 47 primigravidas in spontaneous nonnal labour at tenn were divided into two groups depending on the presence or absence of coupled uterine contractions during active labour. During Inonitoring with a pressure- tip intra-uterine catheter, 24 patients developed coupled contractions and ...

  13. Chromium Speciation Analysis by Ion Chromatography Coupled ...

    African Journals Online (AJOL)

    Two methods coupling ion chromatography with inductively coupled plasma - optical emission spectroscopy (ICP-OES) were developed for the simultaneous separation and determination of Cr(III) and Cr(VI) species. In the first method, anion chromatography with sodium bicarbonate/carbonate solution as the eluent was ...

  14. Large N baryons, strong coupling theory, quarks

    International Nuclear Information System (INIS)

    Sakita, B.

    1984-01-01

    It is shown that in QCD the large N limit is the same as the static strong coupling limit. By using the static strong coupling techniques some of the results of large N baryons are derived. The results are consistent with the large N SU(6) static quark model. (author)

  15. Rayleigh scattering in coupled microcavities: theory.

    Science.gov (United States)

    Vörös, Zoltán; Weihs, Gregor

    2014-12-03

    In this paper we theoretically study how structural disorder in coupled semiconductor heterostructures influences single-particle scattering events that would otherwise be forbidden by symmetry. We extend the model of Savona (2007 J. Phys.: Condens. Matter 19 295208) to describe Rayleigh scattering in coupled planar microcavity structures, and find that effective filter theories can be ruled out.

  16. Synchronization of indirectly coupled Lorenz oscillators: An ...

    Indian Academy of Sciences (India)

    Partial synchronization occurs in a population of chemical oscillators coupled through the concentration of chemical in the surrounding solutions [19]. Two nonlinear chaotic systems coupled indirectly through a common dynamic environment synchronize to in-phase or anti-phase state [20]. The early stages of Alzheimer's ...

  17. Intimate Partner Violence in Interracial Couples: A Comparison to White and Ethnic Minority Monoracial Couples

    Science.gov (United States)

    Fusco, Rachel A.

    2010-01-01

    The number of interracial couples in the U.S. is growing, but they often receive little support. Although previous studies have explored the relationship between low social support and decreased relationship satisfaction in interracial couples, there are few studies on intimate partner violence (IPV) in these couples. To better understand IPV in…

  18. Coupled Coincidence Point and Coupled Common Fixed Point Theorems in Partially Ordered Metric Spaces with -Distance

    Directory of Open Access Journals (Sweden)

    Ilić Dejan

    2010-01-01

    Full Text Available We introduce the concept of a -compatible mapping to obtain a coupled coincidence point and a coupled point of coincidence for nonlinear contractive mappings in partially ordered metric spaces equipped with -distances. Related coupled common fixed point theorems for such mappings are also proved. Our results generalize, extend, and unify several well-known comparable results in the literature.

  19. Tool-change coupling for robots

    International Nuclear Information System (INIS)

    Cooper, C.

    1988-01-01

    A coupling device for use in enabling a robotic unit to couple automatically with any one of a number of tools, comprises two coupling parts connected respectively to the tool and the arm. The two parts can be brought into interengaged relationship by appropriate manipulation of the arm and can be locked together by means of a locking element, controlled by piston and cylinder assembly which enters a tapered bore in a spigot after the spigot, which is mounted on the coupling part, has entered a bore in the other coupling part. The parts also incorporate registering passages for providing continuity of pressurised air supply between the robotic unit and a fluid-powered device incorporated in the tool. (author)

  20. Strong Coupling Corrections in Quantum Thermodynamics

    Science.gov (United States)

    Perarnau-Llobet, M.; Wilming, H.; Riera, A.; Gallego, R.; Eisert, J.

    2018-03-01

    Quantum systems strongly coupled to many-body systems equilibrate to the reduced state of a global thermal state, deviating from the local thermal state of the system as it occurs in the weak-coupling limit. Taking this insight as a starting point, we study the thermodynamics of systems strongly coupled to thermal baths. First, we provide strong-coupling corrections to the second law applicable to general systems in three of its different readings: As a statement of maximal extractable work, on heat dissipation, and bound to the Carnot efficiency. These corrections become relevant for small quantum systems and vanish in first order in the interaction strength. We then move to the question of power of heat engines, obtaining a bound on the power enhancement due to strong coupling. Our results are exemplified on the paradigmatic non-Markovian quantum Brownian motion.

  1. Probabilistic graphs using coupled random variables

    Science.gov (United States)

    Nelson, Kenric P.; Barbu, Madalina; Scannell, Brian J.

    2014-05-01

    Neural network design has utilized flexible nonlinear processes which can mimic biological systems, but has suffered from a lack of traceability in the resulting network. Graphical probabilistic models ground network design in probabilistic reasoning, but the restrictions reduce the expressive capability of each node making network designs complex. The ability to model coupled random variables using the calculus of nonextensive statistical mechanics provides a neural node design incorporating nonlinear coupling between input states while maintaining the rigor of probabilistic reasoning. A generalization of Bayes rule using the coupled product enables a single node to model correlation between hundreds of random variables. A coupled Markov random field is designed for the inferencing and classification of UCI's MLR `Multiple Features Data Set' such that thousands of linear correlation parameters can be replaced with a single coupling parameter with just a (3%, 4%) reduction in (classification, inference) performance.

  2. Strong Coupling between Plasmons and Organic Semiconductors

    Directory of Open Access Journals (Sweden)

    Joel Bellessa

    2014-05-01

    Full Text Available In this paper we describe the properties of organic material in strong coupling with plasmon, mainly based on our work in this field of research. The strong coupling modifies the optical transitions of the structure, and occurs when the interaction between molecules and plasmon prevails on the damping of the system. We describe the dispersion relation of different plasmonic systems, delocalized and localized plasmon, coupled to aggregated dyes and the typical properties of these systems in strong coupling. The modification of the dye emission is also studied. In the second part, the effect of the microscopic structure of the organics, which can be seen as a disordered film, is described. As the different molecules couple to the same plasmon mode, an extended coherent state on several microns is observed.

  3. Universal Stabilization of a Parametrically Coupled Qubit

    Science.gov (United States)

    Lu, Yao; Chakram, S.; Leung, N.; Earnest, N.; Naik, R. K.; Huang, Ziwen; Groszkowski, Peter; Kapit, Eliot; Koch, Jens; Schuster, David I.

    2017-10-01

    We autonomously stabilize arbitrary states of a qubit through parametric modulation of the coupling between a fixed frequency qubit and resonator. The coupling modulation is achieved with a tunable coupling design, in which the qubit and the resonator are connected in parallel to a superconducting quantum interference device. This allows for quasistatic tuning of the qubit-cavity coupling strength from 12 MHz to more than 300 MHz. Additionally, the coupling can be dynamically modulated, allowing for single-photon exchange in 6 ns. Qubit coherence times exceeding 20 μ s are maintained over the majority of the range of tuning, limited primarily by the Purcell effect. The parametric stabilization technique realized using the tunable coupler involves engineering the qubit bath through a combination of photon nonconserving sideband interactions realized by flux modulation, and direct qubit Rabi driving. We demonstrate that the qubit can be stabilized to arbitrary states on the Bloch sphere with a worst-case fidelity exceeding 80%.

  4. Biologically inspired coupled antenna beampattern design

    International Nuclear Information System (INIS)

    Akcakaya, Murat; Nehorai, Arye

    2010-01-01

    We propose to design a small-size transmission-coupled antenna array, and corresponding radiation pattern, having high performance inspired by the female Ormia ochracea's coupled ears. For reproduction purposes, the female Ormia is able to locate male crickets' call accurately despite the small distance between its ears compared with the incoming wavelength. This phenomenon has been explained by the mechanical coupling between the Ormia's ears, which has been modeled by a pair of differential equations. In this paper, we first solve these differential equations governing the Ormia ochracea's ear response, and convert the response to the pre-specified radio frequencies. We then apply the converted response of the biological coupling in the array factor of a uniform linear array composed of finite-length dipole antennas, and also include the undesired electromagnetic coupling due to the proximity of the elements. Moreover, we propose an algorithm to optimally choose the biologically inspired coupling for maximum array performance. In our numerical examples, we compute the radiation intensity of the designed system for binomial and uniform ordinary end-fire arrays, and demonstrate the improvement in the half-power beamwidth, sidelobe suppression and directivity of the radiation pattern due to the biologically inspired coupling.

  5. Reduction of coupling parameters and duality

    International Nuclear Information System (INIS)

    Oehme, R.; Max-Planck-Institut fuer Physik, Muenchen

    2000-01-01

    The general method of the reduction in the number of coupling parameters is discussed. Using renormalization group invariance, theories with several independent couplings are related to a set of theories with a single coupling parameter. The reduced theories may have particular symmetries, or they may not be related to any known symmetry. The method is more general than the imposition of invariance properties. Usually, there are only a few reduced theories with an asymptotic power series expansion corresponding to a renormalizable Lagrangian. There also exist 'general' solutions containing non-integer powers and sometimes logarithmic factors. As an example for the use of the reduction method, the dual magnetic theories associated with certain supersymmetric gauge theories are discussed. They have a superpotential with a Yukawa coupling parameter. This parameter is expressed as a function of the gauge coupling. Given some standard conditions, a unique, isolated power series solution of the reduction equations is obtained. After reparameterization, the Yukawa coupling is proportional to the square of the gauge coupling parameter. The coefficient is given explicitly in terms of the numbers of colors and flavors. 'General' solutions with non-integer powers are also discussed. A brief list is given of other applications of the reduction method. (orig.)

  6. Coupling Between Waveguide-Fed Slot Arrays

    Science.gov (United States)

    Rengarajan, Sembiam

    2011-01-01

    Coupling between two waveguide-fed planar slot arrays has been investigated using full-wave analysis. The analysis employs the method-of-moments solution to the pertinent coupled integral equations for the aperture electric field of all slots. In order to compute coupling between two arrays, the input port of the first array is excited with a TE(sub 10) mode wave while the second one is match-terminated. After solving the moment method matrix equations, the aperture fields of all slots are obtained and thereby the TE(sub 10) mode wave received at the input port of the second array is determined. Coupling between two arrays is the ratio of the wave amplitude arriving in the second array port to the incident wave amplitude at the first array port. The coupling mechanism has been studied as a function of spacing between arrays in different directions, e.g. the electric field plane, the magnetic field plane, and the diagonal plane. Computed coupling values are presented for different array geometries. This work is novel since it provides a good understanding of coupling between waveguide-fed slot arrays as a function of spacing and orientation for different aperture distributions and array architectures. This serves as a useful tool for antenna design engineers and system engineers.

  7. Biologically inspired coupled antenna beampattern design

    Energy Technology Data Exchange (ETDEWEB)

    Akcakaya, Murat; Nehorai, Arye, E-mail: makcak2@ese.wustl.ed, E-mail: nehorai@ese.wustl.ed [Department of Electrical and Systems Engineering, Washington University in St Louis, St Louis, MO 63130 (United States)

    2010-12-15

    We propose to design a small-size transmission-coupled antenna array, and corresponding radiation pattern, having high performance inspired by the female Ormia ochracea's coupled ears. For reproduction purposes, the female Ormia is able to locate male crickets' call accurately despite the small distance between its ears compared with the incoming wavelength. This phenomenon has been explained by the mechanical coupling between the Ormia's ears, which has been modeled by a pair of differential equations. In this paper, we first solve these differential equations governing the Ormia ochracea's ear response, and convert the response to the pre-specified radio frequencies. We then apply the converted response of the biological coupling in the array factor of a uniform linear array composed of finite-length dipole antennas, and also include the undesired electromagnetic coupling due to the proximity of the elements. Moreover, we propose an algorithm to optimally choose the biologically inspired coupling for maximum array performance. In our numerical examples, we compute the radiation intensity of the designed system for binomial and uniform ordinary end-fire arrays, and demonstrate the improvement in the half-power beamwidth, sidelobe suppression and directivity of the radiation pattern due to the biologically inspired coupling.

  8. Traders' behavioral coupling and market phase transition

    Science.gov (United States)

    Ma, Rong; Zhang, Yin; Li, Honggang

    2017-11-01

    Traditional economic theory is based on the assumption that traders are completely independent and rational; however, trading behavior in the real market is often coupled by various factors. This paper discusses behavioral coupling based on the stock index in the stock market, focusing on the convergence of traders' behavior, its effect on the correlation of stock returns and market volatility. We find that the behavioral consensus in the stock market, the correlation degree of stock returns, and the market volatility all exhibit significant phase transitions with stronger coupling.

  9. Coupled Michigan MHD - Rice Convection Model Results

    Science.gov (United States)

    de Zeeuw, D.; Sazykin, S.; Wolf, D.; Gombosi, T.; Powell, K.

    2002-12-01

    A new high performance Rice Convection Model (RCM) has been coupled to the adaptive-grid Michigan MHD model (BATSRUS). This fully coupled code allows us to self-consistently simulate the physics in the inner and middle magnetosphere. A study will be presented of the basic characteristics of the inner and middle magnetosphere in the context of a single coupled-code run for idealized storm inputs. The analysis will include region-2 currents, shielding of the inner magnetosphere, partial ring currents, pressure distribution, magnetic field inflation, and distribution of pV^gamma.

  10. Generalising the coupling between spacetime and matter

    Energy Technology Data Exchange (ETDEWEB)

    Carloni, Sante, E-mail: sante.carloni@gmail.com

    2017-03-10

    We explore the idea that the coupling between matter and spacetime is more complex than the one originally envisioned by Einstein. We propose that such coupling takes the form of a new fundamental tensor in the Einstein field equations. We then show that the introduction of this tensor can account for dark phenomenology in General Relativity, maintaining a weak field limit compatible with standard Newtonian gravitation. The same paradigm can be applied any other theory of gravitation. We show, as an example, that in the context of conformal gravity a generalised coupling is able to solve compatibility issues between the matter and the gravitational sector.

  11. Generalising the coupling between spacetime and matter

    Directory of Open Access Journals (Sweden)

    Sante Carloni

    2017-03-01

    Full Text Available We explore the idea that the coupling between matter and spacetime is more complex than the one originally envisioned by Einstein. We propose that such coupling takes the form of a new fundamental tensor in the Einstein field equations. We then show that the introduction of this tensor can account for dark phenomenology in General Relativity, maintaining a weak field limit compatible with standard Newtonian gravitation. The same paradigm can be applied any other theory of gravitation. We show, as an example, that in the context of conformal gravity a generalised coupling is able to solve compatibility issues between the matter and the gravitational sector.

  12. Coupling methodology within the software platform alliances

    International Nuclear Information System (INIS)

    Montarnal, Ph.; Deville, E.; Adam, E.; Bengaouer, A.; Dimier, A.; Gaombalet, J.; Loth, L.; Chavant, C.

    2005-01-01

    CEA, ANDRA and EDF are jointly developing the software platform ALLIANCES which aim is to produce a tool for the simulation of nuclear waste storage and disposal repository. This type of simulations deals with highly coupled thermo-hydro-mechanical and chemical (T-H-M-C) processes. A key objective of Alliances is to give the capability for coupling algorithms development between existing codes. The aim of this paper is to present coupling methodology use in the context of this software platform. (author)

  13. Intensity noise coupling in soliton fiber oscillators.

    Science.gov (United States)

    Wan, Chenchen; Schibli, Thomas R; Li, Peng; Bevilacqua, Carlo; Ruehl, Axel; Hartl, Ingmar

    2017-12-15

    We present an experimental and numerical study on the spectrally resolved pump-to-output intensity noise coupling in soliton fiber oscillators. In our study, we observe a strong pump noise coupling to the Kelly sidebands, while the coupling to the soliton pulse is damped. This behavior is observed in erbium-doped as well as holmium-doped fiber oscillators and confirmed by numerical modeling. It can be seen as a general feature of laser oscillators in which soliton pulse formation is dominant. We show that spectral blocking of the Kelly sidebands outside the laser cavity can improve the intensity noise performance of the laser dramatically.

  14. Gluon scattering amplitudes at strong coupling

    Energy Technology Data Exchange (ETDEWEB)

    Alday, Luis F. [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands); Maldacena, Juan [School of Natural Sciences, Institute for Advanced Study, Princeton, NJ 08540 (United States)

    2007-06-15

    We describe how to compute planar gluon scattering amplitudes at strong coupling in N = 4 super Yang Mills by using the gauge/string duality. The computation boils down to finding a certain classical string configuration whose boundary conditions are determined by the gluon momenta. The results are infrared divergent. We introduce the gravity version of dimensional regularization to define finite quantities. The leading and subleading IR divergencies are characterized by two functions of the coupling that we compute at strong coupling. We compute also the full finite form for the four point amplitude and we find agreement with a recent ansatz by Bern, Dixon and Smirnov.

  15. Analysis of Synchronization for Coupled Hybrid Systems

    DEFF Research Database (Denmark)

    Li, Zheng; Wisniewski, Rafal

    2006-01-01

    subsystem will cause low efficiency, inferior control performance and a high wear on the compressor. This paper takes the supermarket refrigeration systems as an example to analyze the synchronization and its coupling strengths of coupled hybrid systems, which may provide a base for further research...... of control strategies. This paper combines topology and section mapping theories together to show a new way of analyzing hybrid systems......In the control systems with coupled multi-subsystem, the subsystems might be synchronized (i.e. all the subsystems have the same operation states), which results in negative influence to the whole system. For example, in the supermarket refrigeration systems, the synchronized switch of each...

  16. Impurity screening in strongly coupled plasma systems

    CERN Document Server

    Kyrkos, S

    2003-01-01

    We present an overview of the problem of screening of an impurity in a strongly coupled one-component plasma within the framework of the linear response (LR) theory. We consider 3D, 2D and quasi-2D layered systems. For a strongly coupled plasma the LR can be determined by way of the known S(k) structure functions. In general, an oscillating screening potential with local overscreening and antiscreening regions emerges. In the case of the bilayer, this phenomenon becomes global, as overscreening develops in the layer of the impurity and antiscreening in the adjacent layer. We comment on the limitations of the LR theory in the strong coupling situation.

  17. Synchronization Phenomena in Coupled Colpitts Circuits

    Directory of Open Access Journals (Sweden)

    Ch. K. Volos

    2014-11-01

    Full Text Available In this work, the case of coupling (bidirectional and unidirectional between two identical nonlinear chaotic circuits via a linear resistor, is studied. The produced dynamical systems have different structure, in regard to other similar works, due to the choice of coupling nodes. As a circuit, a modification of the most well-known nonlinear circuit that can operate in a wide range of radiofrequencies, the Colpitts oscillator, is chosen. The simulation and the experimental results show a variety of dynamical phenomena, such as periodic, quasi-periodic and chaotic behaviors, as well as anti-phase and complete synchronization phenomena, depending on the value of the coupling coefficient.

  18. Analysis of dual coupler nested coupled cavities.

    Science.gov (United States)

    Adib, George A; Sabry, Yasser M; Khalil, Diaa

    2017-12-01

    Coupled ring resonators are now forming the basic building blocks in several optical systems serving different applications. In many of these applications, a small full width at half maximum is required, along with a large free spectral range. In this work, a configuration of passive coupled cavities constituting dual coupler nested cavities is proposed. A theoretical study of the configuration is presented allowing us to obtain analytical expressions of its different spectral characteristics. The transfer function of the configuration is also used to generate design curves while comparing these results with analytical expressions. Finally, the configuration is compared with other coupled cavity configurations.

  19. Coupling methodology within the software platform alliances

    Energy Technology Data Exchange (ETDEWEB)

    Montarnal, Ph.; Deville, E.; Adam, E.; Bengaouer, A. [CEA Saclay, Dept. de Modelisation des Systemes et Structures 91 - Gif-sur-Yvette (France); Dimier, A.; Gaombalet, J.; Loth, L. [Agence Nationale pour la Gestion des Dechets Radioactifs (ANDRA), 92 - Chatenay Malabry (France); Chavant, C. [Electricite de France (EDF), 92 - Clamart (France)

    2005-07-01

    CEA, ANDRA and EDF are jointly developing the software platform ALLIANCES which aim is to produce a tool for the simulation of nuclear waste storage and disposal repository. This type of simulations deals with highly coupled thermo-hydro-mechanical and chemical (T-H-M-C) processes. A key objective of Alliances is to give the capability for coupling algorithms development between existing codes. The aim of this paper is to present coupling methodology use in the context of this software platform. (author)

  20. A-coupled-expanding and distributional chaos

    International Nuclear Information System (INIS)

    Kim, Cholsan; Ju, Hyonhui; Chen, Minghao; Raith, Peter

    2015-01-01

    The concept of A-coupled-expanding maps is one of the more natural and useful ideas generalized from the horseshoe map which is commonly known as a criterion of chaos. It is well known that distributional chaos is one of the concepts which reflect strong chaotic behavior. In this paper, we focus on the relationship between A-coupled-expanding and distributional chaos. We prove two theorems which give sufficient conditions for a strictly A-coupled-expanding map to be distributionally chaotic in the senses of two kinds, where A is an m × m irreducible transition matrix

  1. The Optimal Income Taxation of Couples

    DEFF Research Database (Denmark)

    Kleven, Henrik Jacobsen; Kreiner, Claus Thustrup; Saez, Emmanuel

    2009-01-01

    This paper analyzes the general nonlinear optimal income tax for couples, a multidimensional screening problem. Each couple consists of a primary earner who always participates in the labor market, but makes an hours-of-work choice, and a secondary earner who chooses whether or not to work....... If second-earner participation is a signal of the couple being better (worse) off, we prove that optimal tax schemes display a positive tax (subsidy) on secondary earnings and that the tax (subsidy) on secondary earnings decreases with primary earnings and converges to zero asymptotically. We present...

  2. Synchronization of coupled chaotic dynamics on networks

    Indian Academy of Sciences (India)

    www.ias.ac.in/article/fulltext/pram/064/03/0455-0464. Keywords. Dynamical systems; linear stability analysis; floating nodes. Abstract. We review some recent work on the synchronization of coupled dynamical systems on a variety of networks.

  3. Gauge coupling unification in six dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H.M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)]|[Carnegie-Mellon Univ., Pittsburgh, PA (United States). Dept. of Physics

    2006-11-15

    We compute the one-loop gauge couplings in six-dimensional non-Abelian gauge theories on the T{sup 2}/Z{sub 2} orbifold with general GUT breaking boundary conditions. For concreteness, we apply the obtained general formulae to the gauge coupling running in a 6D SO(10) orbifold GUT where the GUT group is broken down to the standard model gauge group up to an extra U(1). We find that the one-loop corrections depend on the parity matrices encoding the orbifold boundary conditions as well as the volume and shape moduli of extra dimensions. When the U(1) is broken by the VEV of bulk singlets, the accompanying extra color triplets also affect the unification of the gauge couplings. In this case, the B-L breaking scale is closely linked to the compactification scales for maintaining a success of the gauge coupling unification. (orig.)

  4. Tensor coupling and pseudospin symmetry in nuclei

    International Nuclear Information System (INIS)

    Alberto, P.; Castro, A.S. de; Lisboa, R.; Malheiro, M.

    2005-01-01

    In this work we study the contribution of the isoscalar tensor coupling to the realization of pseudospin symmetry in nuclei. Using realistic values for the tensor coupling strength, we show that this coupling reduces noticeably the pseudospin splittings, especially for single-particle levels near the Fermi surface. By using an energy decomposition of the pseudospin energy splittings, we show that the changes in these splittings come mainly through the changes induced in the lower radial wave function for the low-lying pseudospin partners and through changes in the expectation value of the pseudospin-orbit coupling term for surface partners. This allows us to confirm the conclusion already reached in previous studies, namely that the pseudospin symmetry in nuclei is of a dynamical nature

  5. Improving plasmonic waveguides coupling efficiency using nanoantennas

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Bouillard, Jean-Sebastien

    2012-01-01

    . The classical dipole antenna scheme can be improved by changing the nanoantenna geometry, adding constructive elements such as reflecting bars and mirrors and using arrays of antennas. The modelling designates that the coupling efficiency from a vertical fiber to a plasmonic waveguide can be improved more than......Plasmonic waveguides bear a lot of potential for photonic applications. However, one of the challenges for implementing them in devices is the low coupling efficiency to and from optical fibers. We report on our approach to facilitate the coupling efficiency with the use of metallic nanoantennas...... in 180 times in comparison with a direct fiber-waveguide coupling. Pros and cons of each configuration are discussed. Fabrication and characterisation results are reported....

  6. Sympathetic Nervous System Synchrony in Couple Therapy.

    Science.gov (United States)

    Karvonen, Anu; Kykyri, Virpi-Liisa; Kaartinen, Jukka; Penttonen, Markku; Seikkula, Jaakko

    2016-07-01

    The aim of this study was to test whether there is statistically significant sympathetic nervous system (SNS) synchrony between participants in couple therapy. To our knowledge, this is the first study to measure psychophysiological synchrony during therapy in a multiactor setting. The study focuses on electrodermal activity (EDA) in the second couple therapy session from 10 different cases (20 clients, 10 therapists working in pairs). The EDA concordance index was used as a measure of SNS synchrony between dyads, and synchrony was found in 85% of all the dyads. Surprisingly, co-therapists exhibited the highest levels of synchrony, whereas couples exhibited the lowest synchrony. The client-therapist synchrony was lower than that of the co-therapists, but higher than that of the couples. A Video Abstract is available next to the online version of this article on the JMFT web site. © 2016 American Association for Marriage and Family Therapy.

  7. Electroweak effective couplings for future precision experiments

    Energy Technology Data Exchange (ETDEWEB)

    Jegerlehner, F. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik

    2011-07-15

    The leading hadronic effects in electroweak theory derive from vacuum polarization which are non-perturbative hadronic contributions to the running of the gauge couplings, the electromagnetic {alpha}{sub em}(s) and the SU(2){sub L} coupling {alpha}{sub 2}(s). I report on my recent package alphaQED [1], which besides the effective fine structure constant {alpha}{sub em}(s) also allows for a fairly precise calculation of the SU(2){sub L} gauge coupling {alpha}{sub 2}(s). I will briefly review the role, future requirements and possibilities. Applied together with the Rhad package by Harlander and Steinhauser [2], the package allows to calculate all SM running couplings as well as running sin{sup 2} {theta} versions with state-of-the-art accuracy. (orig.)

  8. Coupled DM Heating in SCDEW Cosmologies

    Directory of Open Access Journals (Sweden)

    Silvio Bonometto

    2017-08-01

    Full Text Available Strongly-Coupled Dark Energy plus Warm dark matter (SCDEW cosmologies admit the stationary presence of ∼1% of coupled-DM and DE, since inflationary reheating. Coupled-DM fluctuations therefore grow up to non-linearity even in the early radiative expansion. Such early non-linear stages are modelized here through the evolution of a top-hat density enhancement, reaching an early virial balance when the coupled-DM density contrast is just 25–26, and the DM density enhancement is ∼10 % of the total density. During the time needed to settle in virial equilibrium, the virial balance conditions, however, continue to modify, so that “virialized” lumps undergo a complete evaporation. Here, we outline that DM particles processed by overdensities preserve a fraction of their virial momentum. Although fully non-relativistic, the resulting velocities (moderately affect the fluctuation dynamics over greater scales, entering the horizon later on.

  9. Men together: understanding the gay couple.

    Science.gov (United States)

    Berger, R M

    1990-01-01

    The present study surveyed male gay couples to determine how their relationships began and were maintained, the types of conflict they experienced, and how the issues of monogamy, sexual behavior and AIDS affected the relationships. Ninety-two couples responded to the survey. The gay bar was the most common initial meeting place and relationships had lasted from less than one to 35 years. Few had had a commitment ceremony, although many reported wanting one if it were available. Most of the close friends of respondents were also gay couples and about two-thirds of family members were supportive of the relationship. The most persistent conflicts centered around finances and relations with family members. Virtually all respondents described their relationships as monogamous, but only about half practiced safe-sex. More attention needs to be given to understanding male couples and to targeting AIDS-prevention messages to them.

  10. FUNCTIONALIZED CALIXSPHERANDS - SYNTHESIS AND PEPTIDE COUPLING

    NARCIS (Netherlands)

    BAKKER, WII; HAAS, M; DENHERTOG, HJ; VERBOOM, W; DEZEEUW, D; BRUINS, AP; REINHOUDT, DN

    1994-01-01

    Calixspherands, like 1, form kinetically stable complexes with alkali metal cations. For practical in vivo applications coupling of these complexes with carrier molecules is mandatory, Therefore, a general method for the synthesis of functionalized calixspherand 17 was developed starting from

  11. A Miniature Coupled Bistable Vibration Energy Harvester

    International Nuclear Information System (INIS)

    Zhu, D; Arthur, D C; Beeby, S P

    2014-01-01

    This paper reports the design and test of a miniature coupled bistable vibration energy harvester. Operation of a bistable structure largely depends on vibration amplitude rather than frequency, which makes it very promising for wideband vibration energy harvesting applications. A coupled bistable structure consists of a pair of mobile magnets that create two potential wells and thus the bistable phenomenon. It requires lower excitation to trigger bistable operation compared to conventional bistable structures. Based on previous research, this work focused on miniaturisation of the coupled bistable structure for energy harvesting application. The proposed bistable energy harvester is a combination of a Duffing's nonlinear structure and a linear assisting resonator. Experimental results show that the output spectrum of the miniature coupled bistable vibration energy harvester was the superposition of several spectra. It had a higher maximum output power and a much greater bandwidth compared to simply the Duffing's structure without the assisting resonator

  12. On Gauge Invariance and Minimal Coupling

    CERN Document Server

    Jenkins, Elizabeth E; Trott, Michael

    2013-01-01

    The principle of minimal coupling has been used in the study of Higgs boson interactions to argue that certain higher dimensional operators in the low-energy effective theory generalization of the Standard Model are suppressed by loop factors, and thus smaller than others. It also has been extensively used to analyze beyond-the-standard-model theories. We show that in field theory, and even in quantum mechanics, the concept of minimal coupling is ill-defined and inapplicable as a general principle, and give many pedagogical examples which illustrate this fact. We also clarify some related misconceptions about the dynamics of strongly coupled gauge theories. Many arguments in the literature on Higgs boson interactions that use minimal coupling, particularly in pseudo-Goldstone Higgs theories, are inherently flawed.

  13. A coupled-stability index for ENSO

    Science.gov (United States)

    Jin, Fei-Fei; Kim, Seon Tae; Bejarano, Luis

    2006-12-01

    Based on the simple framework of the recharge oscillator for El Niño-Southern Oscillation (ENSO), this paper describes the formulation of a coupled stability index for the large-scale tropical ocean-atmosphere interactions in the equatorial Pacific region. This index, referred to as the Bjerknes (BJ) stability index, takes its negative contributions from the mean upwelling and thermal damping and its positive contributions from the thermocline, the zonal advection, and the Ekman feedbacks. The validity of the BJ stability index formula is tested through a detailed eigen-analysis of an intermediate-coupled model, which shows that the BJ stability index captures the dependence of growth rate of the leading coupled ENSO-like mode on various climate conditions. The general formula of the BJ stability index may be useful for assessing the coupled stability of ENSO and its sensitivity to changes in tropical climate conditions.

  14. Demonstration of Coupled Tiamat Single Assembly Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Novascone, Stephen R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hales, Jason D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gardner, Russell [Idaho National Lab. (INL), Idaho Falls, ID (United States); Pawlowski, R. P. P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pastore, Giovanni [Idaho National Lab. (INL), Idaho Falls, ID (United States); Toth, Alex [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Clarno, Kevin T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Collins, Benjamin S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stimpson, Shane G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Powers, Jeffrey J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-01

    This report corresponds to milestone L3:PHI.PCI.P15.03, which was originally intended to investigate the time discretization approaches with the newly developed fully coupled Tiamat capability, targeting single assembly problems.

  15. Homework assignments in couple and family therapy.

    Science.gov (United States)

    Dattilio, Frank M

    2002-05-01

    Homework has been cited as an integral part of a number of theoretical orientations and therapy formats; unfortunately, very little has been written about its use with couples and families. This is despite the fact that many couple and family therapists espouse the use of homework or out-of-session assignments in order to help the effects of therapy jell. This article reviews some of the empirical literature on homework assignments and their effectiveness in the domain of therapy for families and couples. It also highlights the effectiveness of and the need for out-of-session assignments in treatment. A case illustration is used to demonstrate how homework assignments may be used as a significant change agent in couple and family treatment. Copyright 2002 Wiley Periodicals, Inc.

  16. Common factors of change in couple therapy.

    Science.gov (United States)

    Davis, Sean D; Lebow, Jay L; Sprenkle, Douglas H

    2012-03-01

    Though it is clear from meta-analytic research that couple therapy works well, it is less clear how couple therapy works. Efforts to attribute change to the unique ingredients of a particular model have consistently turned up short, leading many researchers to suggest that change is due to common factors that run through different treatment approaches and settings. The purpose of this article is to provide an empirically based case for several common factors in couple therapy, and discuss clinical, training, and research implications for a common factors couple therapy paradigm. Critical distinctions between model-driven and common factors paradigms are also discussed, and a moderate common factors approach is proposed as a more useful alternative to an extreme common factors approach. Copyright © 2011. Published by Elsevier Ltd.

  17. Strategic Coupling Based on Natural Resources

    DEFF Research Database (Denmark)

    Hauge, Mads Martinus

    -building approach rooted in the Global Production Network (GPN) framework constitutes the analytical approach to the thesis, providing pertinent conceptualizations to explore and discuss how a globalized regional development unfolds. The main theoretical concept of the thesis is that of strategic coupling......, an established concept within the GPN framework that explores and explains how local assets are molded to complement the needs of the global market. However, existing applications of the notion of strategic coupling do not cover the situation in which a resource-based economy is coupled with the world market......, nor does it take into account the implications of a strategic coupling beyond relations between firms and regional institutions. It is imperative that the transformations of local spaces, resources and actors are examined and brought to light to gain an understanding of the possibilities...

  18. Plasmonic solutions for coupling and modulation

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Babicheva, Viktoriia; Malureanu, Radu

    We present our design results for efficient coupling and modulation in plasmonic structures. Fiber coupling to a plasmonic slot waveguide is significantly increased by a metallic nanoantenna with additional reflectors or by the configuration of several connected antennas. We also show that the pl......We present our design results for efficient coupling and modulation in plasmonic structures. Fiber coupling to a plasmonic slot waveguide is significantly increased by a metallic nanoantenna with additional reflectors or by the configuration of several connected antennas. We also show...... that the plasmonic four-layer waveguide with patterned ITO layer can modulate light with higher transmission and the same modulation depth as a waveguide with a uniform ITO layer....

  19. Neurocognitive Impairment: Addressing Couple and Family Challenges.

    Science.gov (United States)

    Rolland, John S

    2017-12-01

    Conditions involving neurocognitive impairment pose enormous challenges to couples and families. However, research and practice tend to focus narrowly on immediate issues for individual caregivers and their dyadic relationship with the affected member. A broad family systems approach with attention to family processes over time is needed in training, practice, and research. In this paper, Rolland's Family Systems Illness model provides a guiding framework to consider the interaction of different psychosocial types of neurocognitive conditions and their evolution over time with individual, couple, and family life-course development. Discussion addresses key family and couple issues with mild-to-severe cognitive impairment and progressive dementias, including: communication, multigenerational legacies, threatened future neurocognitive disability, ambiguous loss, decisional capacity, reaching limits, placement decisions, issues for adult children and spousal caregivers, and the transformation of intimate bonds. Principles and guidelines are offered to help couples and families master complex challenges, deepen bonds, and forge positive pathways ahead. © 2017 Family Process Institute.

  20. Unification of couplings in the MSSM

    CERN Document Server

    Carena, Marcela

    1996-01-01

    I briefly summarize the main features related to the unification of gauge and Yukawa couplings in the MSSM, emphasizing the predictions derived in this framework, which are of special interest in the light of present and near--future experiments

  1. Strong Josephson Coupling in Planar Graphene Junctions

    Science.gov (United States)

    Park, Jinho; Lee, Gil-Ho; Lee, Jae Hyeong; Takane, Yositake; Imura, Ken-Ichiro; Taniguchi, Takashi; Watanabe, Kenji; Lee, Hu-Jong

    A recent breakthrough of processing graphene, employing encapsulation by hexagonal boron nitride layers (BGB structure), allows realizing the ballistic carrier transport in graphene. Thereafter, ballistic Josephson coupling has been studied by closely edge-contacted BGB structure with two superconducting electrodes. Here, we report on the strong Josephson coupling with planar graphene junction in truly short and ballistic regime. Our device showed high transmission probability and the junction critical current (IC) oscillating for sweeping the gate voltage along with the normal conductance oscillation (Fabry-Perot oscillations), providing a direct evidence for the ballistic nature of the junction pair current. We also observed the convex-upward shape of decreasing critical currents with increasing temperature, canonical properties of the short Josephson coupling. By fitting these curves into theoretical models, we demonstrate the strong Josephson coupling in our devices, which is also supported by the exceptionally large value of ICRN ( 2 Δ / e RNis the normal resistance).

  2. Configurational forces and couples for crack propagation

    Directory of Open Access Journals (Sweden)

    Jarić Jovo P.

    2002-01-01

    Full Text Available Following the approach of Gurtin and Podio-Guidugli (1998, the problem of crack propagation based on the notion of configurational forces and couples in micropolar continua is considered. .

  3. The Optimal Income Taxation of Couples

    DEFF Research Database (Denmark)

    Kleven, Henrik Jacobsen; Kreiner, Claus Thustrup; Satz, Emmanuel

    This paper analyzes the optimal income tax treatment of couples. Each couple is modelled as a single rational economic agent supplying labor along two dimensions: primary and secondary earnings. We consider fully general joint income tax systems. Separate taxation is never optimal if social welfare...... depends on total couple incomes. In a model where secondary earners make only a binary work decision (work or not work), we demonstrate that the marginal tax rate of the primary earner is lower when the spouse works. As a result, the tax distortion on the secondary earner decreases with the earnings...... of the primary earner and actually vanishes to zero asymptotically. Such negative jointness is optimal because redistribution from two-earner toward one-earner couples is more valuable when primary earner income is lower. We also consider a model where both spouses display intensive labor supply responses...

  4. Errata :Chromosomal Abnormalities in Couples with Recurrent ...

    African Journals Online (AJOL)

    Chromosomal Abnormalities in Couples with Recurrent Abortions in Lagos, Nigeria. Akinde OR, Daramola A O, Taiwo I A, Afolayan M O and Akinsola Af. Sonographic Mammary Gland Density Pattern in Women in Selected ommunities of Southern Nigeria.

  5. Intermittent chaotic chimeras for coupled rotators

    DEFF Research Database (Denmark)

    Olmi, Simona; Martens, Erik Andreas; Thutupalli, Shashi

    2015-01-01

    Two symmetrically coupled populations of N oscillators with inertia m display chaotic solutions with broken symmetry similar to experimental observations with mechanical pendulums. In particular, we report evidence of intermittent chaotic chimeras, where one population is synchronized and the other...

  6. Pension plan participation among married couples.

    Science.gov (United States)

    Dushi, Irena; Iams, Howard M

    2013-01-01

    We present descriptive statistics on pension participation and types of pensions among married couples, using data from the 1996/2008 Panels of the Survey of Income and Program Participation and Social Security administrative records. Previous research has focused on pension coverage by marital status, but has not examined couples as a unit. Because couples usually share income, viewing them as a unit provides a better picture of potential access to income from retirement plans. Our analysis compares 1998 and 2009 data because substantial changes occurred in the pension landscape over this decade that could have influenced the prevalence of different pension plans, although we observe modest changes in participation rates and types of plans over the period. We find that in 20 percent of couples, neither spouse participated in a pension plan; in 10 percent, the wife was the only participant; and in 37 percent, the husband was the only participant.

  7. Synchronization in complex networks with adaptive coupling

    International Nuclear Information System (INIS)

    Zhang Rong; Hu Manfeng; Xu Zhenyuan

    2007-01-01

    Generally it is very difficult to realized synchronization for some complex networks. In order to synchronize, the coupling coefficient of networks has to be very large, especially when the number of coupled nodes is larger. In this Letter, we consider the problem of synchronization in complex networks with adaptive coupling. A new concept about asymptotic stability is presented, then we proved by using the well-known LaSalle invariance principle, that the state of such a complex network can synchronize an arbitrary assigned state of an isolated node of the network as long as the feedback gain is positive. Unified system is simulated as the nodes of adaptive coupling complex networks with different topologies

  8. Superconducting Resonant Inductive Power Coupling, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed effort will develop a technology to wirelessly and efficiently transfer power over hundreds of meters via resonant inductive coupling. The key...

  9. A study of coupled thermoacoustic engines

    Science.gov (United States)

    Gillman, Brenna Jane

    In the development of thermoacoustic energy conversion from heat to electricity, an array configuration of heat engines can yield high acoustic power output. Arrays consisting of multiple thermoacoustic engines have been constructed in such a way that the heat driven acoustic engines radiate sound into a common cavity where a piezoelectric transducer is used to convert acoustic power into electrical signal. Coupling effects between two or more self-sustaining thermoacoustic engines, operating near 2.5 kHz, have been observed and considered in terms of synchronization. Two types of coupling were observed to be present in the system: mass coupling and acoustic coupling. It was found that for a weaker mass coupling, in the absence of acoustic coupling, anti-phase synchronization was observed. In-phase synchronization was observed for stronger mass coupling. To vary the acoustic coupling present in this system, the volume of the cavity, and the separation distance between engines were varied. In-phase synchronization was observed for each combination of two engines tested at every cavity volume and separation distance, however the average phase difference measured between oscillators was not the same for each cavity volume tested. It was found that the cavity volume with 228 cm3 was the only cavity tested to result in synchronization with an average phase difference of approximately zero degrees, and also maintain oscillations in a stable acoustic cavity mode for each array tested. Acoustic pressure amplitude was measured to be proportional to the number of engines in the array when scaled by the amplitude of each single engine operating alone for arrays up to four engines. Since an array consisting of four engines was shown to synchronize and produce coherent sound, the coupling between engines was identified as global coupling. To determine the threshold of frequency difference for synchronization, two coupled engines were detuned. It was found that the threshold

  10. Dynamics of Coupled Quantum Spin Chains

    International Nuclear Information System (INIS)

    Schulz, H.J.

    1996-01-01

    Static and dynamical properties of weakly coupled antiferromagnetic spin chains are treated using a mean-field approximation for the interchain coupling and exact results for the resulting effective one-dimensional problem. Results for staggered magnetization, Nacute eel temperature, and spin wave excitations are in agreement with experiments on KCuF 3 . The existence of a narrow longitudinal mode is predicted. The results are in agreement with general scaling arguments, contrary to spin wave theory. copyright 1996 The American Physical Society

  11. Equine Assisted Couples Therapy: An Exploratory Study

    OpenAIRE

    Ham, Taylor Marie

    2013-01-01

    Equine assisted psychotherapy (EAP) is an emerging experiential methodologythat has recently gained recognition as a method for addressing a range of presentingproblems for a wide variety of client populations. Couples therapy is one area that thepractice of equine assisted psychotherapy has recently gained traction. This studydescribes the practice of equine assisted couples therapy in terms of practitionercharacteristics, approach to treatment, therapeutic goals and outcomes. Mental healthp...

  12. Synchronization of weakly coupled canard oscillators

    OpenAIRE

    Köksal Ersöz, Elif; Desroches, Mathieu; Krupa, Martin

    2017-01-01

    International audience; Synchronization has been studied extensively in the context of weakly coupled oscillators using the so-called phase response curve (PRC) which measures how a change of the phase of an oscillator is affected by a small perturbation. This approach was based upon the work of Malkin, and it has been extended to relaxation oscillators. Namely, synchronization conditions were established under the weak coupling assumption, leading to a criterion for the existence of synchron...

  13. Coupled finite element modeling of piezothermoelastic materials

    Science.gov (United States)

    Senousy, M. S.; Rajapakse, R. K. N. D.; Gadala, M.

    2007-04-01

    The governing equations of piezo-thermoelastic materials show full coupling between mechanical, electric, and temperature fields. It is often assumed in the literature that in high-frequency oscillations, the coupling between the temperature and mechanical displacement and electric field is small and, therefore, can be neglected. A solution for the temperature field is then determined from an uncoupled equation. A finite element (FE) model that accounts for full coupling between the mechanical, electric, and thermal fields, nonlinear constitutive behavior and heat generation resulting from dielectric losses under alternating driving fields is under development. This paper presents a linear fully coupled model as an early development of the fully coupled nonlinear FE model. In the linear model, a solution for all field variables is obtained simultaneously and compared with the uncoupled solution. The finite element model is based on the weighted-residual principle and uses 2-D four-node isoparametric finite elements with four degrees of freedom per node. A thin piezoelectric square disk is modeled to obtain some preliminary understanding of the coupled fields in a piezoelectric stack actuator.

  14. Neuron-glia metabolic coupling and plasticity.

    Science.gov (United States)

    Magistretti, Pierre J

    2006-06-01

    The coupling between synaptic activity and glucose utilization (neurometabolic coupling) is a central physiological principle of brain function that has provided the basis for 2-deoxyglucose-based functional imaging with positron emission tomography (PET). Astrocytes play a central role in neurometabolic coupling, and the basic mechanism involves glutamate-stimulated aerobic glycolysis; the sodium-coupled reuptake of glutamate by astrocytes and the ensuing activation of the Na-K-ATPase triggers glucose uptake and processing via glycolysis, resulting in the release of lactate from astrocytes. Lactate can then contribute to the activity-dependent fuelling of the neuronal energy demands associated with synaptic transmission. An operational model, the 'astrocyte-neuron lactate shuttle', is supported experimentally by a large body of evidence, which provides a molecular and cellular basis for interpreting data obtained from functional brain imaging studies. In addition, this neuron-glia metabolic coupling undergoes plastic adaptations in parallel with adaptive mechanisms that characterize synaptic plasticity. Thus, distinct subregions of the hippocampus are metabolically active at different time points during spatial learning tasks, suggesting that a type of metabolic plasticity, involving by definition neuron-glia coupling, occurs during learning. In addition, marked variations in the expression of genes involved in glial glycogen metabolism are observed during the sleep-wake cycle, with in particular a marked induction of expression of the gene encoding for protein targeting to glycogen (PTG) following sleep deprivation. These data suggest that glial metabolic plasticity is likely to be concomitant with synaptic plasticity.

  15. Switchable and tunable film bulk acoustic resonator fabricated using barium strontium titanate active layer and Ta{sub 2}O{sub 5}/SiO{sub 2} acoustic reflector

    Energy Technology Data Exchange (ETDEWEB)

    Sbrockey, N. M., E-mail: sbrockey@structuredmaterials.com; Tompa, G. S. [Structured Materials Industries, Inc., Piscataway, New Jersey 08854 (United States); Kalkur, T. S.; Mansour, A. [Department of Electrical and Computer Engineering, Colorado State University at Colorado Springs, Colorado Springs, Colorado 80933 (United States); Khassaf, H.; Yu, H.; Aindow, M.; Alpay, S. P. [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States)

    2016-08-01

    A solidly mounted acoustic resonator was fabricated using a Ba{sub 0.60}Sr{sub 0.40}TiO{sub 3} (BST) film deposited by metal organic chemical vapor deposition. The device was acoustically isolated from the substrate using a Bragg reflector consisting of three pairs of Ta{sub 2}O{sub 5}/SiO{sub 2} layers deposited by chemical solution deposition. Transmission electron microscopy verified that the Bragg reflector was not affected by the high temperatures and oxidizing conditions necessary to process high quality BST films. Electrical characterization of the resonator demonstrated a quality factor (Q) of 320 and an electromechanical coupling coefficient (K{sub t}{sup 2}) of 7.0% at 11 V.

  16. Gay male couples' attitudes toward using couples-based voluntary HIV counseling and testing.

    Science.gov (United States)

    Mitchell, Jason W

    2014-01-01

    Many men who have sex with men acquire HIV from their primary male partners while in a relationship. Studies with gay couples have demonstrated that relationship characteristics and testing behaviors are important to examine for HIV prevention. Recently, couples-based voluntary HIV counseling and testing (CVCT) has become available to male couples throughout the U.S. However, HIV-negative couples' attitudes toward using CVCT and how their relationship characteristics may affect their use of CVCT remain largely unknown. This information is particularly relevant for organizations that offer CVCT. To assess couples' attitudes, and associated factors toward using CVCT, a cross-sectional study design was used with a novel Internet-based recruitment method to collect dyadic data from a national sample of 275 HIV-negative gay couples. Multivariate multilevel modeling was used to identify factors associated with differences between and within couples about their attitudes towards using CVCT. Findings revealed that couples were "somewhat" to "very likely" to use CVCT. More positive attitudes toward using CVCT were associated with couples who had higher levels of relationship satisfaction and commitment toward their sexual agreement and among those who had at least one partner having had sex outside of the relationship. Less positive attitude toward using CVCT was associated with couples who had higher levels of trust toward their partners being dependable. Differences within couples, including age between partners, whether sex had occurred outside of the relationship, and value toward a sexual agreement also affected their attitudes toward using CVCT. Providing additional testing methods may help HIV-negative gay couples better manage their HIV risk.

  17. The Experience of Couples in the Process of Treatment of Pathological Gambling: Couple vs. Individual Therapy

    OpenAIRE

    Joël Tremblay; Magali Dufour; Karine Bertrand; Nadine Blanchette-Martin; Francine Ferland; Annie-Claude Savard; Marianne Saint-Jacques; Mélissa Côté

    2018-01-01

    Context: Couple treatment for pathological gambling is an innovative strategy. There are some results supporting its potential effectiveness, but little is known about the subjective experiences of the participants.Objective: The aim of this article is to document the experiences of gamblers and their partners participating in one of two treatments, namely individual or couple.Method: In a study aiming to evaluate the efficacy of the Integrative Couple Treatment for Pathological Gambling (ICT...

  18. [Enhanced prenatal HIV couple oriented counselling session and couple communication about HIV (ANRS 12127 Prenahtest Trial)].

    Science.gov (United States)

    Plazy, M; Orne-Gliemann, J; Balestre, E; Miric, M; Darak, S; Butsashvili, M; Tchendjou, P; Dabis, F; Desgrées du Loû, A

    2013-08-01

    The Prenahtest study investigated the efficacy of a couple-oriented HIV counselling session (COC) in encouraging couple HIV counselling and testing, and improving intra-couple communication about sexual and reproductive health. We report here on the effect of COC on intra-couple communication about HIV. Within this 4-country trial (India, Georgia, Dominican Republic and Cameroon), 484 to 491 pregnant women per site were recruited and individually randomized to receive either the COC intervention, enhanced counselling with role playing, or standard post-test HIV counselling. Women were interviewed at recruitment, before HIV testing (T0), and 2 to 8 weeks after post-test HIV counselling (T1). Four dichotomous variables documented intra-couple communication about HIV at T1: 1) discussion about HIV, 2) discussion about condom use, 3) suggesting HIV testing and 4) suggesting couple HIV counselling to the partner. An intra-couple HIV communication index was created: low degree of communication ("yes" response to zero or one of the four variables), intermediate degree of communication ("yes" to two or three variables) or high degree of communication ("yes" to the four variables). To estimate the impact of COC on the intra-couple HIV communication index, multivariable logistic regressions were conducted. One thousand six hundred and seven women were included in the analysis of whom 54 (3.4%) were HIV-infected (49 in Cameroon). In the four countries, the counselling group was associated with intra-couple HIV communication (P≤0.03): women allocated to the COC group were significantly more likely to report high or intermediate degrees of intra-couple communication about HIV (versus low degree of communication) than women allocated to standard counselling. COC improved short-term communication about HIV within couples in different sociocultural contexts, a positive finding for a couple approach to HIV prevention. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  19. A Tightly Coupled Non-Equilibrium Magneto-Hydrodynamic Model for Inductively Coupled RF Plasmas

    Science.gov (United States)

    2016-02-29

    Journal Article 3. DATES COVERED (From - To) 12 May 2015 – 06 Oct 2015 4. TITLE AND SUBTITLE A Tightly Coupled Non- Equilibrium Magneto-Hydrodynamic...development a tightly coupled magneto-hydrodynamic model for Inductively Coupled Radio- Frequency (RF) Plasmas. Non Local Thermodynamic Equilibrium (NLTE...effects are described based on a hybrid State-to-State (StS) approach. A multi-temperature formulation is used to account for thermal non- equilibrium

  20. Outcomes of couples with infidelity in a community-based sample of couple therapy.

    Science.gov (United States)

    Atkins, David C; Marín, Rebeca A; Lo, Tracy T Y; Klann, Notker; Hahlweg, Kurt

    2010-04-01

    Infidelity is an often cited problem for couples seeking therapy, but the research literature to date is very limited on couple therapy outcomes when infidelity is a problem. The current study is a secondary analysis of a community-based sample of couple therapy in Germany and Austria. Outcomes for 145 couples who reported infidelity as a problem in their relationship were compared with 385 couples who sought therapy for other reasons. Analyses based on hierarchical linear modeling revealed that infidelity couples were significantly more distressed and reported more depressive symptoms at the start of therapy but continued improving through the end of therapy and to 6 months posttherapy. At the follow-up assessment, infidelity couples were not statistically distinguishable from non-infidelity couples, replicating previous research. Sexual dissatisfaction did not depend on infidelity status. Although there was substantial missing data, sensitivity analyses suggested that the primary findings were not due to missing data. The current findings based on a large community sample replicated previous work from an efficacy trial and show generally optimistic results for couples in which there has been an affair. 2010 APA, all rights reserved

  1. Photonic crystal coupled cavities with increased beaming and free space coupling efficiency

    International Nuclear Information System (INIS)

    Haddadi, S.; Yacomotti, A. M.; Sagnes, I.; Beaudoin, G.; Le Gratiet, L.; Levenson, J. A.; Raineri, F.

    2013-01-01

    We implement the band-folding approach in coupled photonic crystal L3 (three missing holes) nanocavities and demonstrate a dramatic beaming improvement compatible with high-Q operation. Directional laser effect is achieved. In addition, resonant free-space coupling to the symmetric and anti-symmetric hybrid modes of the photonic molecule is shown. We measure the coupling to each mode as a function of the spatial position of the laser spot, which can be used as a technique to probe the symmetry of coupled cavity modes.

  2. Tropical cyclone sensitivity to ocean coupling in the ECMWF coupled model

    Science.gov (United States)

    Mogensen, Kristian S.; Magnusson, Linus; Bidlot, Jean-Raymond

    2017-05-01

    We present an investigation of the performance of the ECMWF coupled atmosphere-waves-ocean model for different ocean and atmosphere resolutions on a series of tropical cyclones in the Western Pacific with the aim to better understand the coupled feedback mechanisms in these extreme conditions. For some of the test cases, we only find little impact of coupling the atmosphere to the ocean, while in others, we observe a very large impact. To further understand these differences, we have selected two tropical cyclones (TCs) as case studies: TC Haiyan (with small impact of coupling) and TC Neoguri (with large impact of coupling). The comparison between these two cases suggests that the upper ocean stratification is the key in determining the strength of the coupled feedback. A strong coupled feedback is found whenever the ocean heat content of the upper layer is low while a very weak coupled feedback is found whenever the ocean has a thick warm mixed layer. The oceanographic response to tropical cyclones for the two storms has been compared to sea surface temperature and derived surface currents from drifting buoys and to subsurface observations from Argo and ship launched XBT's. These comparisons show that we are able to realistically reproduce the atmospheric and oceanographic interaction during tropical cyclone conditions which gives us confidence that the coupled modeling system is physically sound.

  3. Couples' experiences of infertility: a phenomenological study.

    Science.gov (United States)

    Imeson, M; McMurray, A

    1996-11-01

    If nurses are to work effectively with families in contemporary society, their practice activities must be appropriately informed. Families exposed to new technologies, such as in vitro fertilization (IVF) require care that is sensitive to their particular experience. Infertile couples have been the subject of a substantial body of research, however, most studies to date focus on the physiological effects of infertility and do not take into account the context in which the experience takes place, or the meanings that people assign to this experience. The purpose of this study was to examine in-depth the experience of couples undergoing IVF treatment for infertility. A phenomenological approach was adopted for the study. A purposive sample of six couples was selected for interview. Data were generated from taped interviews and the researcher's observational field notes. Data analysis was in accordance with the procedure outlined by Colaizzi (1978). Interview responses were categorized by examining the participants' transcripts and identifying significant statements and meanings. Themes which emerged from the statements were then identified, and cross-case comparisons were made to confirm or modify these themes. Four key themes emerged from the data: life changes; powerlessness; hope-disappointment cycle; and social isolation. All couples undergoing infertility treatment experienced life changes which included: lifestyle changes, various physical and emotional changes, and changes in their relationships. There was a perceived loss of control over many aspects of their lives. Couples also described a cycle, alternating feelings of hope and disappointment. Most of the couples reported feelings of social isolation associated with being infertile, that were intensified by having to deal with the inappropriate responses of others. Findings from this study will add to the knowledge base on infertility, and contribute to recommendations for improving the way nurses guide

  4. Nanocatalysts for Suzuki cross-coupling reactions

    KAUST Repository

    Fihri, Aziz

    2011-01-01

    This critical review deals with the applications of nanocatalysts in Suzuki coupling reactions, a field that has attracted immense interest in the chemical, materials and industrial communities. We intend to present a broad overview of nanocatalysts for Suzuki coupling reactions with an emphasis on their performance, stability and reusability. We begin the review with a discussion on the importance of Suzuki cross-coupling reactions, and we then discuss fundamental aspects of nanocatalysis, such as the effects of catalyst size and shape. Next, we turn to the core focus of this review: the synthesis, advantages and disadvantages of nanocatalysts for Suzuki coupling reactions. We begin with various nanocatalysts that are based on conventional supports, such as high surface silica, carbon nanotubes, polymers, metal oxides and double hydroxides. Thereafter, we reviewed nanocatalysts based on non-conventional supports, such as dendrimers, cyclodextrin and magnetic nanomaterials. Finally, we discuss nanocatalyst systems that are based on non-conventional media, i.e., fluorous media and ionic liquids, for use in Suzuki reactions. At the end of this review, we summarise the significance of nanocatalysts, their impacts on conventional catalysis and perspectives for further developments of Suzuki cross-coupling reactions (131 references). © 2011 The Royal Society of Chemistry.

  5. Status report on SHARP coupling framework.

    Energy Technology Data Exchange (ETDEWEB)

    Caceres, A.; Tautges, T. J.; Lottes, J.; Fischer, P.; Rabiti, C.; Smith, M. A.; Siegel, A.; Yang, W. S.; Palmiotti, G.

    2008-05-30

    This report presents the software engineering effort under way at ANL towards a comprehensive integrated computational framework (SHARP) for high fidelity simulations of sodium cooled fast reactors. The primary objective of this framework is to provide accurate and flexible analysis tools to nuclear reactor designers by simulating multiphysics phenomena happening in complex reactor geometries. Ideally, the coupling among different physics modules (such as neutronics, thermal-hydraulics, and structural mechanics) needs to be tight to preserve the accuracy achieved in each module. However, fast reactor cores in steady state mode represent a special case where weak coupling between neutronics and thermal-hydraulics is usually adequate. Our framework design allows for both options. Another requirement for SHARP framework has been to implement various coupling algorithms that are parallel and scalable to large scale since nuclear reactor core simulations are among the most memory and computationally intensive, requiring the use of leadership-class petascale platforms. This report details our progress toward achieving these goals. Specifically, we demonstrate coupling independently developed parallel codes in a manner that does not compromise performance or portability, while minimizing the impact on individual developers. This year, our focus has been on developing a lightweight and loosely coupled framework targeted at UNIC (our neutronics code) and Nek (our thermal hydraulics code). However, the framework design is not limited to just using these two codes.

  6. Compensating strong coupling with large charge

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Gaume, Luis [Theory Department - CERN,CH-1211 Geneva 23 (Switzerland); Simons Center for Geometry and Physics, State University of New York,Stony Brook, NY-11794-3636 (United States); Loukas, Orestis; Orlando, Domenico; Reffert, Susanne [Albert Einstein Center for Fundamental Physics,Institute for Theoretical Physics, University of Bern,Sidlerstrasse 5, CH-3012 Bern (Switzerland)

    2017-04-11

    We study some (conformal) field theories with global symmetries in the sector where the value of the global charge Q is large. We find (as expected) that the low energy excitations of this sector are described by the general form of Goldstone’s theorem in the non-relativistic regime. We also derive the unexpected result, first presented in https://www.doi.org/10.1007/JHEP12(2015)071, that the effective field theory describing such sector of fixed Q contains effective couplings λ{sub eff}∼λ{sup b}/Q{sup a}, where λ is the original coupling. Hence, large charge leads to weak coupling. In the last section of the paper we present an outline of how to compute anomalous dimensions of the O(n) model in this limit.

  7. Numerical simulations of coupled problems in engineering

    CERN Document Server

    2014-01-01

    This book presents and discusses mathematical models, numerical methods and computational techniques used for solving coupled problems in science and engineering. It takes a step forward in the formulation and solution of real-life problems with a multidisciplinary vision, accounting for all of the complex couplings involved in the physical description. Simulation of multifaceted physics problems is a common task in applied research and industry. Often a suitable solver is built by connecting together several single-aspect solvers into a network. In this book, research in various fields was selected for consideration: adaptive methodology for multi-physics solvers, multi-physics phenomena and coupled-field solutions, leading to computationally intensive structural analysis. The strategies which are used to keep these problems computationally affordable are of special interest, and make this an essential book.

  8. A strongly coupled quark-gluon plasma

    Energy Technology Data Exchange (ETDEWEB)

    Shuryak, Edward [Department of Physics and Astronomy, University at Stony Brook, NY 11794 (United States)

    2004-08-01

    Successful description of robust collective flow phenomena at RHIC by ideal hydrodynamics, recent observations of bound c-barc,q-barq states on the lattice, and other theoretical developments indicate that QGP produced at RHIC, and probably in a wider temperature region T{sub c} < T < 4T{sub c}, is not a weakly coupled quasiparticle gas as believed previously. We discuss how strong the interaction is and why it seems to generate hundreds of binary channels with bound states, surviving well inside the QGP phase. We in particular discuss their effect on pressure and viscosity. We conclude by reviewing the similar phenomena for other 'strongly coupled systems', such as (i) strongly coupled supersymmetric theories studied via Maldacena duality; (ii) trapped ultra-cold atoms with very large scattering length, tuned to Feschbach resonances.

  9. Scalable BDDC Algorithms for Cardiac Electromechanical Coupling

    KAUST Repository

    Pavarino, L. F.

    2017-03-17

    The spread of electrical excitation in the cardiac muscle and the subsequent contraction-relaxation process is quantitatively described by the cardiac electromechanical coupling model. The electrical model consists of the Bidomain system, which is a degenerate parabolic system of two nonlinear partial differential equations (PDEs) of reaction-diffusion type, describing the evolution in space and time of the intra- and extracellular electric potentials. The PDEs are coupled through the reaction term with a stiff system of ordinary differential equations (ODEs), the membrane model, which describes the flow of the ionic currents through the cellular membrane and the dynamics of the associated gating variables. The mechanical model consists of the quasi-static finite elasticity system, modeling the cardiac tissue as a nearly-incompressible transversely isotropic hyperelastic material, and coupled with a system of ODEs accounting for the development of biochemically generated active force.

  10. Interferometric output coupling of ring optical oscillators.

    Science.gov (United States)

    Chaitanya Kumar, S; Esteban-Martin, A; Ebrahim-Zadeh, M

    2011-04-01

    We demonstrate the successful deployment of an antiresonant ring (ARR) interferometer within a ring optical resonator and its use for absolute optimization of output power. The integration of the ARR interferometer in a folded arm of the ring oscillator provides continuously variable output coupling over broad spectral range and under any operating conditions. We demonstrate the technique using a picosecond optical parametric oscillator (OPO), where we show continuously adjustable output coupling and optimization of the output power for different pump power conditions, from 3.5 W to 13.5 W. By operating the OPO under an optimized output coupling at 14 W of pump power, we obtain >5 W of extracted signal power, more than 2.6 times that with a ~5% conventional output coupler. We also show that the inclusion of the ARR interferometer has no detrimental effect on the spatial, temporal, and spectral characteristics of OPO output.

  11. Coupled Photonic Crystal Cavity Array Laser

    DEFF Research Database (Denmark)

    Schubert, Martin

    This thesis describes the design, fabrication and characterization of photonic crystal slab lasers. The main focus is on coupled photonic crystal cavity lasers which are examined in great detail. The cavity type which is mainly explored consists of a defect formed by a single missing hole...... in the quadratic lattice. Processing techniques are developed and optimized in order fabricate photonic crystals membranes in gallium arsenide with quantum dots as gain medium and in indium gallium arsenide phosphide with quantum wells as gain medium. Several key issues in process to ensure good quality...... are identified such as the size and material for the carrier wafer in the III-V etch and the importance of removing all remains of the e-beam lithography mask after the etch of the hard mask. Detailed simulations are shown for a simple system with two coupled cavities in different coupling directions...

  12. Dynamics of microbubble oscillators with delay coupling

    Science.gov (United States)

    Heckman, C. R.; Sah, S. M.; Rand, R. H.

    2010-10-01

    We investigate the stability of the in-phase mode in a system of two delay-coupled bubble oscillators. The bubble oscillator model is based on a 1956 paper by Keller and Kolodner. Delay coupling is due to the time it takes for a signal to travel from one bubble to another through the liquid medium that surrounds them. Using techniques from the theory of differential-delay equations as well as perturbation theory, we show that the equilibrium of the in-phase mode can be made unstable if the delay is long enough and if the coupling strength is large enough, resulting in a Hopf bifurcation. We then employ Lindstedt's method to compute the amplitude of the limit cycle as a function of the time delay. This work is motivated by medical applications involving noninvasive localized drug delivery via microbubbles.

  13. Synchronization in networks with heterogeneous coupling delays

    Science.gov (United States)

    Otto, Andreas; Radons, Günter; Bachrathy, Dániel; Orosz, Gábor

    2018-01-01

    Synchronization in networks of identical oscillators with heterogeneous coupling delays is studied. A decomposition of the network dynamics is obtained by block diagonalizing a newly introduced adjacency lag operator which contains the topology of the network as well as the corresponding coupling delays. This generalizes the master stability function approach, which was developed for homogenous delays. As a result the network dynamics can be analyzed by delay differential equations with distributed delay, where different delay distributions emerge for different network modes. Frequency domain methods are used for the stability analysis of synchronized equilibria and synchronized periodic orbits. As an example, the synchronization behavior in a system of delay-coupled Hodgkin-Huxley neurons is investigated. It is shown that the parameter regions where synchronized periodic spiking is unstable expand when increasing the delay heterogeneity.

  14. Coupled seismoacoustic modes on the seafloor

    Science.gov (United States)

    Butler, Rhett; Lomnitz, Cinna

    2002-05-01

    Wave-to-wave coupling arises when an acoustic pulse selects a Rayleigh mode of the same speed and both travel together swapping energy across an interface [Ewing et al., 1957]. A distinctive signal is observed at the Hawaii-2 Observatory for purely oceanic paths from earthquakes on the Blanco and Mendocino Fracture Zones, off the coast of North America. The signal appears to be a composite of undispersed higher Rayleigh modes propagating along the ocean floor both in the sediments and in the water. The new coupled modes are identified by their frequency composition and their phase and group velocities. Seismoacoustic coupling at the seafloor is conditioned on (a) the presence of a low-velocity interface at the ocean floor, and (b) the wavelength of the Rayleigh component being shorter than the depth of the water layer.

  15. Phase coupling gravity and astronomical mass discrepancies

    International Nuclear Information System (INIS)

    Sanders, R.H.

    1988-01-01

    A previous author has proposed a new theory of gravity in which an additional long-range force is associated with a complex scalar field. The unique aspect of the theory is that only the phase of the complex scalar field couples to matter; hence, the designation 'phase coupling gravity'. The scalar field Lagrangian density contains a self-interaction potential which, in original form, depends upon the sixth power of the scalar amplitude because then the resulting weak field phenomenology is similar to that of MOND, the empirically motivated modification of Newton's law in the limit of low accelerations previously suggested in order to account for the observed mass discrepancies in large astronomical systems. In the present paper I explore versions of phase coupling gravity with alternative forms for the scalar self-interaction. (author)

  16. Coupled Transmission Lines as Impedance Transformer

    DEFF Research Database (Denmark)

    Jensen, Thomas; Zhurbenko, Vitaliy; Krozer, Viktor

    2007-01-01

    A theoretical investigation of the use of a coupled line section as an impedance transformer is presented. We show how to properly select the terminations of the coupled line structures for effective matching of real and complex loads in both narrow and wide frequency ranges. The corresponding...... circuit configurations and the design procedures are proposed. Synthesis relations are derived and provided for efficient matching circuit construction. Design examples are given to demonstrate the flexibility and limitations of the design methods and to show their validity for practical applications....... Wideband matching performance with relative bandwidth beyond 100% and return loss > 20 dB is demonstrated both theoretically and experimentally. Good agreement is achieved between the measured and predicted performance of the coupled line transformer section....

  17. Beam echoes in the presence of coupling

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Axel [Case Western Reserve U.

    2017-10-03

    Transverse beam echoes could provide a new technique of measuring diusion characteristics orders of magnitude faster than the current methods; however, their interaction with many accelerator parameters is poorly understood. Using a program written in C, we explored the relationship between coupling and echo strength. We found that echoes could be generated in both dimensions, even with a dipole kick in only one dimension. We found that the echo eects are not destroyed even when there is strong coupling, falling o only at extremely high coupling values. We found that at intermediate values of skew quadrupole strength, the decoherence time of the beam is greatly increased, causing a destruction of the echo eects. We found that this is caused by a narrowing of the tune width of the particles. Results from this study will help to provide recommendations to IOTA (Integrable Optics Test Accelerator) for their upcoming echo experiment.

  18. Compensating strong coupling with large charge

    CERN Document Server

    Alvarez-Gaume, Luis; Orlando, Domenico; Reffert, Susanne

    2017-04-11

    We study (conformal) field theories with global symmetries in the sector where the value of the global charge $Q$ is large. We find (as expected) that the low energy excitations of this sector are described by the general form of Goldstone's theorem in the non-relativistic regime. We also derive the unexpected result, first presented in [Hellerman:2015], that the effective field theory describing such sector of fixed $Q$ contains effective couplings $\\lambda_{\\text{eff}}\\sim \\lambda^b /Q^{a}$, where $\\lambda$ is the original coupling. Hence, large charge leads to weak coupling. In the last section of the paper we present an outline of how to compute anomalous dimensions in this limit.

  19. Measuring interrelating within couples: The Couple's Relating to Each Other Questionnaires (CREOQ)

    NARCIS (Netherlands)

    Birtchnell, J.; Voortman, S.G.H.; Jong, C.A.J. de; Gordon, D.

    2006-01-01

    The Couple's Relating to Each Other Questionnaires (CREOQ) are a set of four questionnaires for measuring negative forms of interrelating within couples. They enable each partner to rate his/her relating to the other and the other's relating to him/her. They are based upon the theoretical structure

  20. Coupled intertwiner dynamics: A toy model for coupling matter to spin foam models

    Science.gov (United States)

    Steinhaus, Sebastian

    2015-09-01

    The universal coupling of matter and gravity is one of the most important features of general relativity. In quantum gravity, in particular spin foams, matter couplings have been defined in the past, yet the mutual dynamics, in particular if matter and gravity are strongly coupled, are hardly explored, which is related to the definition of both matter and gravitational degrees of freedom on the discretization. However, extracting these mutual dynamics is crucial in testing the viability of the spin foam approach and also establishing connections to other discrete approaches such as lattice gauge theories. Therefore, we introduce a simple two-dimensional toy model for Yang-Mills coupled to spin foams, namely an Ising model coupled to so-called intertwiner models defined for SU (2 )k. The two systems are coupled by choosing the Ising coupling constant to depend on spin labels of the background, as these are interpreted as the edge lengths of the discretization. We coarse grain this toy model via tensor network renormalization and uncover an interesting dynamics: the Ising phase transition temperature turns out to be sensitive to the background configurations and conversely, the Ising model can induce phase transitions in the background. Moreover, we observe a strong coupling of both systems if close to both phase transitions.

  1. Psychosocial services for couples in infertility treatment: what do couples really want?

    Science.gov (United States)

    Read, Suzanne C; Carrier, Marie-Eve; Boucher, Marie-Eve; Whitley, Robert; Bond, Sharon; Zelkowitz, Phyllis

    2014-03-01

    To describe the psychosocial supports that infertile couples desire to help cope with infertility-related distress, which psychosocial services they sought, and the benefits and drawbacks of these services. Qualitative interview study with 32 heterosexual infertile couples seeking infertility treatment. Maximum variation sampling was used; data were analyzed using thematic analysis. Most couples desired psychosocial support, but only half of the sample sought support. Some couples met with psychologists for help with relationship conflict and coping strategies. Participants suggested peer mentoring to fulfill needs for coping, shared experience, and guidance through the treatment process. Couples also desired written information about practical and emotional aspects of treatment. Negative attitudes toward psychological counseling and a lack of information about support services prevented some couples from seeking support. Infertile couples expressed numerous needs for psychosocial supports, but often felt that supports were not available. A variety of services should be offered in order to fulfill patients' varied needs. Awareness of the reasons why patients desire psychosocial services will help clinicians to refer patients to currently available psychosocial supports, and will aid in the development of appropriate supports, including couples counseling, peer mentoring, and written information in lay language. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  2. Excitation of anti-symmetric coupled spoof SPPs in 3D SIS waveguides based on coupling

    Science.gov (United States)

    Li-li, Tian; Yang, Chen; Jian-long, Liu; Kai, Guo; Ke-ya, Zhou; Yang, Gao; Shu-tian, Liu

    2016-07-01

    According to the electromagnetic field distributions, there exist two kinds of coupled spoof surface plasmon polaritons (SSPPs), the symmetric and anti-symmetric modes, in the three-dimensional (3D) subwavelength spoof-insulator-spoof (SIS) waveguide. We study the dispersion and excitation of the two kinds of coupled SSPPs supported by the 3D SIS waveguide. The evolution of the dispersion with the thickness and gap width of the waveguide is numerically investigated, and we give a theoretical analysis according to the coupling mechanism. Specially, based on the coupling mechanism, we design a zipper structure, through which the excitation and propagation of the anti-symmetric coupled modes can be realized effectively. Project supported by the National Basic Research Program of China (Grant No. 2013CBA01702) and the National Natural Science Foundation of China (Grant Nos. 61377016, 61575055, 10974039, 61307072, 61308017, and 61405056).

  3. Controllable nonlinearity in a dual-coupling optomechanical system under a weak-coupling regime

    Science.gov (United States)

    Zhu, Gui-Lei; Lü, Xin-You; Wan, Liang-Liang; Yin, Tai-Shuang; Bin, Qian; Wu, Ying

    2018-03-01

    Strong quantum nonlinearity gives rise to many interesting quantum effects and has wide applications in quantum physics. Here we investigate the quantum nonlinear effect of an optomechanical system (OMS) consisting of both linear and quadratic coupling. Interestingly, a controllable optomechanical nonlinearity is obtained by applying a driving laser into the cavity. This controllable optomechanical nonlinearity can be enhanced into a strong coupling regime, even if the system is initially in the weak-coupling regime. Moreover, the system dissipation can be suppressed effectively, which allows the appearance of phonon sideband and photon blockade effects in the weak-coupling regime. This work may inspire the exploration of a dual-coupling optomechanical system as well as its applications in modern quantum science.

  4. Link prediction via generalized coupled tensor factorisation

    DEFF Research Database (Denmark)

    Ermiş, Beyza; Evrim, Acar Ataman; Taylan Cemgil, A.

    2012-01-01

    and higher-order tensors. We propose to use an approach based on probabilistic interpretation of tensor factorisation models, i.e., Generalised Coupled Tensor Factorisation, which can simultaneously fit a large class of tensor models to higher-order tensors/matrices with com- mon latent factors using...... different loss functions. Numerical experiments demonstrate that joint analysis of data from multiple sources via coupled factorisation improves the link prediction performance and the selection of right loss function and tensor model is crucial for accurately predicting missing links....

  5. Superstring threshold corrections to Yukawa couplings

    International Nuclear Information System (INIS)

    Antoniadis, I.; Taylor, T.R.

    1992-12-01

    A general method of computing string corrections to the Kaehler metric and Yukawa couplings is developed at the one-loop level for a general compactification of the heterotic superstring theory. It also provides a direct determination of the so-called Green-Schwarz term. The matter metric has an infrared divergent part which reproduces the field-theoretical anomalous dimensions, and a moduli-dependent part which gives rise to threshold corrections in the physical Yukawa couplings. Explicit expressions are derived for symmetric orbifold compactifications. (author). 20 refs

  6. Deformed nucleon and double-delta coupling

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Afsar (Institute of Physics, Bhubaneswar (India))

    1991-11-01

    Although the coupling constant (f{sub {pi}{Delta}{Delta}} /f{sub {pi}NN}) {sup 2} is of much importance in the context of current research in the role of the double-delta in hadron physics, so far the naive quark model value has been used, which is shown to be poor. Here we obtain a better value for this coupling constant in a deformed nucleon model which would help us to rectify this defect and enable us to conduct a proper study of the exotic double-delta channel. (author).

  7. On matter couplings in N=1 supergravities

    International Nuclear Information System (INIS)

    Galperin, A.; Ogievskiy, V.; Sokatchev, E.

    1983-01-01

    A flexible version of N=1 supergravity is proposed. It contains 28+28 fields and is an extension of the new minimal supergravity version. Matter couplings in various N=1 supergravity versions are discussed. The chiral densities are constructed for non-minimal and flexible versions. Therefore these versions admit a general R-non-invariant matter coupling as the minimal supergravity does. A modified Fayet-Iliopoulos type mechanism is conjectured which apparently can work in the non-minimal and flexible versions without R-symmetry of the superpotential unlike the minimal and new minimal ones

  8. Coupled-cluster computations of atomic nuclei.

    Science.gov (United States)

    Hagen, G; Papenbrock, T; Hjorth-Jensen, M; Dean, D J

    2014-09-01

    In the past decade, coupled-cluster theory has seen a renaissance in nuclear physics, with computations of neutron-rich and medium-mass nuclei. The method is efficient for nuclei with product-state references, and it describes many aspects of weakly bound and unbound nuclei. This report reviews the technical and conceptual developments of this method in nuclear physics, and the results of coupled-cluster calculations for nucleonic matter, and for exotic isotopes of helium, oxygen, calcium, and some of their neighbors.

  9. MOS Current Mode Logic with Capacitive Coupling

    OpenAIRE

    Kirti Gupta; Neeta Pandey; Maneesha Gupta

    2012-01-01

    A new MOS current mode logic (MCML) style exhibiting capacitive coupling to enhance the switching speed of the digital circuits is proposed. The mechanism of capacitive coupling and its effect on the delay are analytically modeled. SPICE simulations to validate the accuracy of the analytical model have been carried out with TSMC 0.18 μm CMOS technology parameters. Several logic gates such as five-stage ring oscillator, NAND, XOR2, XOR3, multiplexer, and demultiplexer based on the proposed log...

  10. Magnetically Coupled Impedance-Source Inverters

    DEFF Research Database (Denmark)

    Loh, Poh Chiang; Blaabjerg, Frede

    2013-01-01

    input-to-output gain and the presence of an impedance network. The former means a high dc-link voltage, which can stress the semiconductor switches unnecessarily. The latter leads to increases in cost and size, which similarly are undesirable. To lessen these concerns, an interesting approach is to use...... magnetically coupled transformers or inductors to raise the gain and modulation ratio simultaneously, while reducing the number of passive components needed. A study of the approach is now presented to show how various existing magnetically coupled inverters can be derived by applying a generic methodology...

  11. Pumping slots: Coupling impedance calculations and estimates

    International Nuclear Information System (INIS)

    Kurennoy, S.

    1993-08-01

    Coupling impedances of small pumping holes in vacuum-chamber walls have been calculated at low frequencies, i.e., for wavelengths large compared to a typical hole size, in terms of electric and magnetic polarizabilities of the hole. The polarizabilities can be found by solving and electro- or magnetostatic problem and are known analytically for the case of the elliptic shape of the hole in a thin wall. The present paper studies the case of pumping slots. Using results of numerical calculations and analytical approximations of polarizabilities, we give formulae for practically important estimates of slot contribution to low-frequency coupling impedances

  12. A general analysis of Wtb anomalous couplings

    Science.gov (United States)

    Cao, Qing-Hong; Yan, Bin; Yu, Jiang-Hao; Zhang, Chen

    2017-06-01

    We investigate new physics effects on the Wtb effective couplings in a model-independent framework. The new physics effects can be parametrized by four independent couplings, , , and . We further introduce a set of parameters x 0, x m , x p and x 5 which exhibit a linear relation to the single top production cross sections. Using recent data for the t-channel single top production cross section σ t , tW associated production cross section σ tW, s-channel single top production cross section σ s , and W-helicity fractions F 0, F L and F R collected at the 8 TeV LHC and Tevatron, we perform a global fit to impose constraints on the top quark effective couplings. Our global fitting results show that the top quark effective couplings are strongly correlated. We show that (i) improving the measurements of σ t and σ tW is important in constraining the correlation of (,) and (,); (ii) and are anti-correlated, and are sensitive to all the four experiments; (iii) and are also anti-correlated, and are sensitive to the F 0 and F L measurements; (iv) the correlation between and is sensitive to the precision of the σ t , σ tW and F 0 measurements. The effective Wtb couplings are studied in three kinds of new physics models: the G(221) = SU(2)1 ⊗ SU(2)2 ⊗ U(1) X models, the vector-like quark models and the Littlest Higgs model with and without T-parity. We show that the Wtb couplings in the left-right model and the un-unified model are sensitive to the ratio of gauge couplings when the new heavy gauge boson’s mass (M W‧) is less than several hundred GeV, but the constraint is loose if M W‧ > 1 TeV. Furthermore, the Wtb couplings in vector-like quark models and the Littlest Higgs models are sensitive to the mixing angles of new heavy particles and SM particles. Supported by National Science Foundation of China (11275009, 11675002, 11635001), National Science Foundation (PHY-1315983, PHY-1316033) and DOE (DE- SC0011095)

  13. Canonical formalism for coupled beam optics

    International Nuclear Information System (INIS)

    Kheifets, S.A.

    1989-09-01

    Beam optics of a lattice with an inter-plane coupling is treated using canonical Hamiltonian formalism. The method developed is equally applicable both to a circular (periodic) machine and to an open transport line. A solution of the equation of a particle motion (and correspondingly transfer matrix between two arbitrary points of the lattice) are described in terms of two amplitude functions (and their derivatives and corresponding phases of oscillations) and four coupling functions, defined by a solution of the system of the first-order nonlinear differential equations derived in the paper. Thus total number of independent parameters is equal to ten. 8 refs

  14. Coupled lasers: phase versus chaos synchronization.

    Science.gov (United States)

    Reidler, I; Nixon, M; Aviad, Y; Guberman, S; Friesem, A A; Rosenbluh, M; Davidson, N; Kanter, I

    2013-10-15

    The synchronization of chaotic lasers and the optical phase synchronization of light originating in multiple coupled lasers have both been extensively studied. However, the interplay between these two phenomena, especially at the network level, is unexplored. Here, we experimentally compare these phenomena by controlling the heterogeneity of the coupling delay times of two lasers. While chaotic lasers exhibit deterioration in synchronization as the time delay heterogeneity increases, phase synchronization is found to be independent of heterogeneity. The experimental results are found to be in agreement with numerical simulations for semiconductor lasers.

  15. Spin–orbit coupling in actinide cations

    DEFF Research Database (Denmark)

    Bagus, Paul S.; Ilton, Eugene S.; Martin, Richard L.

    2012-01-01

    The limiting case of Russell–Saunders coupling, which leads to a maximum spin alignment for the open shell electrons, usually explains the properties of high spin ionic crystals with transition metals. For actinide compounds, the spin–orbit splitting is large enough to cause a significantly reduced...... spin alignment. Novel concepts are used to explain the dependence of the spin alignment on the 5f shell occupation. We present evidence that the XPS of ionic actinide materials may provide direct information about the angular momentum coupling within the 5f shell....

  16. Reentrant transition in coupled noisy oscillators.

    Science.gov (United States)

    Kobayashi, Yasuaki; Kori, Hiroshi

    2015-01-01

    We report on a synchronization-breaking instability observed in a noisy oscillator unidirectionally coupled to a pacemaker. Using a phase oscillator model, we find that, as the coupling strength is increased, the noisy oscillator lags behind the pacemaker more frequently and the phase slip rate increases, which may not be observed in averaged phase models such as the Kuramoto model. Investigation of the corresponding Fokker-Planck equation enables us to obtain the reentrant transition line between the synchronized state and the phase slip state. We verify our theory using the Brusselator model, suggesting that this reentrant transition can be found in a wide range of limit cycle oscillators.

  17. Processes of Change in Self-Directed Couple Relationship Education

    Science.gov (United States)

    Wilson, Keithia L.; Halford, W. Kim

    2008-01-01

    The current study examined the learning processes involved in professionally supported self-directed couple relationship education (CRE). Fifty-nine couples completed Couple CARE, a systematic, self-directed CRE program designed in flexible delivery mode to be completed at home. Couples watched a DVD introducing key relationship ideas and skills…

  18. Analytical solutions of coupled-mode equations for microring ...

    Indian Academy of Sciences (India)

    equivalent to waveguide and single microring coupled system. The 3 × 3 coupled system is equivalent to waveguide and double microring coupled system. In this paper, we adopt a novel approach for obtaining coupled-mode equations for linearly distributed and circularly distributed multiwaveguide systems with different ...

  19. Dynamics of nonlinear oscillators with time-varying conjugate coupling

    Indian Academy of Sciences (India)

    We explore the dynamical consequences of time-varying conjugate coupling in a system of nonlinear oscillators. We analyze the behavior of coupled ... Conjugate coupling; time varying coupling. PACS Nos 05.45.Xt. 1. Introduction ..... MDS acknowledges the financial support from DST,. New Delhi. References. [1] L Glass ...

  20. Collective dynamics of delay-coupled limit cycle oscillators

    Indian Academy of Sciences (India)

    We present a brief overview of the effect of time-delayed coupling on the collective dynamics of such coupled systems. Simple model equations describing two oscillators with a discrete time-delayed coupling as well as those describing linear arrays of a large number of oscillators with time-delayed global or local couplings ...

  1. New limits on quark and lepton weak couplings

    International Nuclear Information System (INIS)

    Barnett, R.M.

    1978-06-01

    The unique determination of the weak neutral-current couplings of u and d quarks is discussed. Knowledge of these quark couplings has important implications for the determination of the electron's couplings. Recent data provide new restrictions on the charged-current couplings of quarks. The implications of these analyses for weak and electromagnetic gauge theories of quarks and leptons are examined

  2. The Experience of Couples in the Process of Treatment of Pathological Gambling: Couple vs. Individual Therapy

    Science.gov (United States)

    Tremblay, Joël; Dufour, Magali; Bertrand, Karine; Blanchette-Martin, Nadine; Ferland, Francine; Savard, Annie-Claude; Saint-Jacques, Marianne; Côté, Mélissa

    2018-01-01

    Context: Couple treatment for pathological gambling is an innovative strategy. There are some results supporting its potential effectiveness, but little is known about the subjective experiences of the participants. Objective: The aim of this article is to document the experiences of gamblers and their partners participating in one of two treatments, namely individual or couple. Method: In a study aiming to evaluate the efficacy of the Integrative Couple Treatment for Pathological Gambling (ICT-PG), couples who were entering specialized treatment for the addiction of one member who was a pathological gambler were randomly assigned to individual or ICT-PG. Nine months after their admission to treatment, gamblers and partners (n = 21 couples; n = 13 ICT-PG; n = 8 individual treatment) were interviewed in semi-structured interviews. A sequenced thematization method was used to extract the major themes. Results: This study highlighted five major themes in the therapeutic process noted by the gamblers and their partners mainly after the couple treatment but also partly through the individual therapy. These were: (1) the gamblers' anxiety about having to reveal their gambling problems in couple therapy; (2) the wish to develop a mutually beneficial understanding of gambling and its effects on the partners in the two types of treatments; (3) the transformation of negative attributions through a more effective intra-couple communication fostered by the couple therapy; (4) the partners' contribution to changes in gambling behavior and prevention of relapses, which were both better supported in couple therapy; and (5) the interpersonal nature of gambling and its connections with the couples' relationship. However, gamblers who were in individual treatment were more likely to mention that their partners' involvement was not necessary. Participants likewise made a few recommendations about the conditions underlying the choice of one treatment method or the other. Discussion

  3. The Experience of Couples in the Process of Treatment of Pathological Gambling: Couple vs. Individual Therapy

    Directory of Open Access Journals (Sweden)

    Joël Tremblay

    2018-01-01

    Full Text Available Context: Couple treatment for pathological gambling is an innovative strategy. There are some results supporting its potential effectiveness, but little is known about the subjective experiences of the participants.Objective: The aim of this article is to document the experiences of gamblers and their partners participating in one of two treatments, namely individual or couple.Method: In a study aiming to evaluate the efficacy of the Integrative Couple Treatment for Pathological Gambling (ICT-PG, couples who were entering specialized treatment for the addiction of one member who was a pathological gambler were randomly assigned to individual or ICT-PG. Nine months after their admission to treatment, gamblers and partners (n = 21 couples; n = 13 ICT-PG; n = 8 individual treatment were interviewed in semi-structured interviews. A sequenced thematization method was used to extract the major themes.Results: This study highlighted five major themes in the therapeutic process noted by the gamblers and their partners mainly after the couple treatment but also partly through the individual therapy. These were: (1 the gamblers' anxiety about having to reveal their gambling problems in couple therapy; (2 the wish to develop a mutually beneficial understanding of gambling and its effects on the partners in the two types of treatments; (3 the transformation of negative attributions through a more effective intra-couple communication fostered by the couple therapy; (4 the partners' contribution to changes in gambling behavior and prevention of relapses, which were both better supported in couple therapy; and (5 the interpersonal nature of gambling and its connections with the couples' relationship. However, gamblers who were in individual treatment were more likely to mention that their partners' involvement was not necessary. Participants likewise made a few recommendations about the conditions underlying the choice of one treatment method or the other

  4. Examination of a failed fifth wheel coupling

    CSIR Research Space (South Africa)

    Fernandes, PJL

    1998-03-01

    Full Text Available to prevent inadvertent opening of the coupling locking mechanism. No alternative safety device was employed to ensure the safety of the modified design. Furthermore, the rubbing plate on the pup-trailer was significantly smaller than that on the fifth wheel...

  5. Air-coupled ultrasonic applications of ferroelectrets

    Czech Academy of Sciences Publication Activity Database

    Bovtun, Viktor; Döring, J.; Wegener, M.; Bartusch, J.; Beck, U.; Erhard, A.; Borisov, V.

    2008-01-01

    Roč. 370, č. 1 (2008), s. 11-17 ISSN 0015-0193 R&D Projects: GA ČR(CZ) GA202/06/0403 Institutional research plan: CEZ:AV0Z10100520 Keywords : air-coupled ultrasonics * non-contact transducers * ferroelectrets * electromechanical properties Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.562, year: 2008

  6. Measurements of Higgs Couplings at ATLAS

    CERN Document Server

    Rescigno, M; The ATLAS collaboration

    2013-01-01

    In this talk Atlas results on Higgs couplings through the fit to the Higgs data in several production and decay modes will be reviewed. Perspectives for further developments with the complete 8 TeV dataset as well as long term perspective with LHC and HL-LHC as presented in the Atlas document for ESG are summarized.

  7. Relativistic ls coupling in scalar potential

    International Nuclear Information System (INIS)

    Martem'yanov, B.V.; Shchepkin, M.G.

    1987-01-01

    On fermion example ls-splitting of the levels in scalar potential in the general case including relativistic range is considered. The derived formulas are compared with the classical ones for the energy concerned with the Thomas spin precession. It is shown that in the relativistic range ls-coupling causes change of rotational excitation spectrum

  8. social problems of the infertile couples

    African Journals Online (AJOL)

    However, helping infertile couples to achieve pregnancy, which is one of the objectives of family planning should not be ne- glected. New technologies for assisted reproduction have led to a great demand for fertility enhancing services. These have how- ever generated intense ethical, legal and social debates in some.

  9. Choices and Motivations of Infertile Couples.

    Science.gov (United States)

    van Balen, Frank; Verdurmen, Jacqueline; Ketting, Evert

    1997-01-01

    Infertile couples' (N=131) consideration of options for dealing with infertility (medical help, adoption, fostering, alternative medicine, and focusing on other life goals) is studied. Options were related to specific motivations including altruistic motives for adoption or foster care. Results, timing of choices, and motivations are discussed.…

  10. Joint Labour Supply Dynamics of Older Couples

    NARCIS (Netherlands)

    Michaud, P.C.

    2003-01-01

    This paper studies the labour force participation dynamics of older couples in the United States.Longitudinal data from the five available waves of the Health and Retirement Study (HRS) is used to investigate if the dynamics introduced by considering both spouses' behavior provide additional

  11. Electrical characteristics for capacitively coupled radio frequency ...

    Indian Academy of Sciences (India)

    MURAT TANISLI

    2017-08-16

    Aug 16, 2017 ... cally parallel. Here, the RF voltage is usually applied to one of the two electrodes and the other electrode is used for grounding. The plasma sheath and bulk plasma ... Nonlinear plasma series resonance (PSR) effect ... Equivalent circuit for the capacitively coupled RF discharge of the homogenous model.

  12. Mechanical core coupling and reactors stability

    International Nuclear Information System (INIS)

    Suarez Antola, R.

    2006-01-01

    Structural parts of nuclear reactors are complex mechanical systems, able to vibrate with a set of proper frequencies when suitably excited. Cyclical variations in the strain state of the materials, including density perturbations, are produced. This periodic changes may affect reactor reactivity. But a variation in reactivity affects reactor thermal power, thus modifying the temperature field of the abovementiones materials. If the variation in temperature fields is fast enough, thermal-mechanical coupling may produce fast variations in strain states, and this, at its turn, modifies the reactivity, and so on. This coupling between mechanical vibrations of the structure and the materials of the core, with power oscillations of the reactor, not only may not be excluded a priori, but it seems that it has been present in some stage of the incidents or accidents that happened during the development of nuclear reactor technology. The purpose of the present communication is: (a) To review and generalize some mathematical models that were proposed in order to describe thermal-mechanical coupling in nuclear reactors. (b) To discuss some conditions in which significant instabilities could arise, including large amplitude power oscillations coupled with mechanical vibrations whose amplitudes are too small to be excluded by conventional criteria of mechanical design. Enough Certain aspects of thr physical safety of nuclear power reactors, that are objected by people that opposes to the renaissance of nucleoelectric generation, are discussed in the framework of the mathematical model proposed in this paper [es

  13. Dual-Career Couples and Academic Science.

    Science.gov (United States)

    Weiler, Susan C.; Yancey, Paul H.

    1992-01-01

    Describes the major challenges of accommodating dual-career couples in academic science and some of the current responses to those challenges from institutions of higher learning. Discusses prevailing perceptions concerning household responsibility, the science work ethic, job procurement, continued discrimination against women, and future…

  14. A Sexual Enhancement Program for Elderly Couples

    Science.gov (United States)

    Rowland, Kay F.; Haynes, Stephen N.

    1978-01-01

    This study examined effects of a group sexual enhancement program for elderly couples. The three two-week phases, pretreatment with no therapist contact, education on human sexual functioning in aging people, and communication exercises-sexual techniques, were methods to improve communication and increase enjoyment of sexual contact. (Author)

  15. Fiber-optic coupled pressure transducer

    International Nuclear Information System (INIS)

    Tallman, C.R.; Wingate, F.P.; Ballard, E.O.

    1979-01-01

    A fiber-optic coupled pressure transducer was developed for measurement of pressure transients produced by fast electrical discharges in laser cavities. A detailed description of the design and performance will be given. Shock tube performance and measurements in direct electrical discharge regions will be presented

  16. Chaos desynchronization in strongly coupled systems

    International Nuclear Information System (INIS)

    Wu Ye; Liu Weiqing; Xiao, Jinghua; Zhan Meng

    2007-01-01

    The dynamics of chaos desynchronization in strongly coupled oscillator systems is studied. We find a new bifurcation from synchronous chaotic state, chaotic short wave bifurcation, i.e. a chaotic desynchronization attractor is new born in the systems due to chaos desynchronization. In comparison with the usual periodic short wave bifurcation, very rich but distinct phenomena are observed

  17. Global chaos synchronization of coupled parametrically excited ...

    Indian Academy of Sciences (India)

    u.vincent@tu-clausthal.de (U E Vincent); njahabdul@yahoo.com (A N Njah). MS received 24 March 2009; ... sufficient criteria for global asymptotic synchronization are derived from which an esti- mated critical coupling is ... ent concepts of synchronization, the reader is referred to the fundamental book by. Pikovsky et al [7].

  18. Coupling superconducting qubits via a cavity bus.

    Science.gov (United States)

    Majer, J; Chow, J M; Gambetta, J M; Koch, Jens; Johnson, B R; Schreier, J A; Frunzio, L; Schuster, D I; Houck, A A; Wallraff, A; Blais, A; Devoret, M H; Girvin, S M; Schoelkopf, R J

    2007-09-27

    Superconducting circuits are promising candidates for constructing quantum bits (qubits) in a quantum computer; single-qubit operations are now routine, and several examples of two-qubit interactions and gates have been demonstrated. These experiments show that two nearby qubits can be readily coupled with local interactions. Performing gate operations between an arbitrary pair of distant qubits is highly desirable for any quantum computer architecture, but has not yet been demonstrated. An efficient way to achieve this goal is to couple the qubits to a 'quantum bus', which distributes quantum information among the qubits. Here we show the implementation of such a quantum bus, using microwave photons confined in a transmission line cavity, to couple two superconducting qubits on opposite sides of a chip. The interaction is mediated by the exchange of virtual rather than real photons, avoiding cavity-induced loss. Using fast control of the qubits to switch the coupling effectively on and off, we demonstrate coherent transfer of quantum states between the qubits. The cavity is also used to perform multiplexed control and measurement of the qubit states. This approach can be expanded to more than two qubits, and is an attractive architecture for quantum information processing on a chip.

  19. Coupled analysis of the HPLWR fuel assembly

    Energy Technology Data Exchange (ETDEWEB)

    Monti, Lanfranco; Schulenberg, Thomas; Starflinger, Joerg [Forschungszentrum Karlsruhe (Germany). Inst. for Nuclear and Energy Technologies

    2008-07-01

    The High Performance Light Water Reactor (HPLWR) [1] is an innovative type of reactor cooled and moderated with water at super-critical pressure. Due to the nominal operation pressure of 25 MPa no two-phase transition occurs and thus the issues related to the nucleate boiling are eliminated permitting a larger coolant temperature rise than for common LWRs and hence the thermodynamic efficiency of the power plant is also increased. The target water heat up, from 550K to 770K, is split into three parts and, because of the associated strong density reduction, the presence of additional in-core flow paths for high density water is required in order to achieve a thermal neutron spectrum. Since the water densities determine the neutron spectrum and hence the power generation which in turn may change the water temperatures and densities, a coupled Neutronic / Thermal-Hydraulic analysis is mandatory even for steady-state conditions as already shown in [2] and [3]. Two stand alone codes where chosen and coupled trough external procedures which exchange the coupling parameters, namely the water density together with the fuel temperature from the thermalhydraulic analysis and the axial power distribution from the neutronic one. This paper will present preliminary results obtained for a steady state coupled analysis of one single HPLWR fuel assembly together with the computational methods developed. (orig.)

  20. Upper ionosphere and magnetospheric-ionospheric coupling

    International Nuclear Information System (INIS)

    Manzano, J.R.

    1989-02-01

    After a presentation of the ionospheric physics and of the earth magnetosphere morphology, generation and dynamics, the magnetosphere-ionosphere coupling in quiet and perturbed conditions is discussed. Some summary information about other planetary magnetospheres, particularly Venus and Jupiter magnetospheres, are finally given. 41 refs, 24 figs