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Chih-hao Chang - One of the best experts on this subject based on the ideXlab platform.

  • 35.4: Enhancing Light Outcoupling of Organic Light‐Emitting Devices by Locating Emitters around the Second Antinode of the Reflective Metal Electrode
    SID Symposium Digest of Technical Papers, 2006
    Co-Authors: Chun-liang Lin, Ting-yi Cho, Chih-hao Chang
    Abstract:

    Due to generally low conductivity and low carrier mobilities of organic materials, organic light-emitting devices (OLEDs) are typically optimized for light outcoupling by locating emitters around the first Antinode of the metal electrode. In this paper, by utilizing device structures containing conductive doping, we investigate theoretically and experimentally the influences of the location of emitters relative to the metal electrode on OLED emission, and show that substantial enhancement in light outcoupling (1.2 times) or forward luminance (1.6 times) could be obtained by placing emitters around the second Antinode instead of the first Antinode. Depending on the detailed condition, the second-Antinode device may also give more directed emission as often observed in strong-micrcavity devices yet without suffering color shift with viewing angles.

  • 35 4 enhancing light outcoupling of organic light emitting devices by locating emitters around the second Antinode of the reflective metal electrode
    SID Symposium Digest of Technical Papers, 2006
    Co-Authors: Chun-liang Lin, Ting-yi Cho, Chih-hao Chang
    Abstract:

    Due to generally low conductivity and low carrier mobilities of organic materials, organic light-emitting devices (OLEDs) are typically optimized for light outcoupling by locating emitters around the first Antinode of the metal electrode. In this paper, by utilizing device structures containing conductive doping, we investigate theoretically and experimentally the influences of the location of emitters relative to the metal electrode on OLED emission, and show that substantial enhancement in light outcoupling (1.2 times) or forward luminance (1.6 times) could be obtained by placing emitters around the second Antinode instead of the first Antinode. Depending on the detailed condition, the second-Antinode device may also give more directed emission as often observed in strong-micrcavity devices yet without suffering color shift with viewing angles.

  • Enhancing light outcoupling of organic light-emitting devices by locating emitters around the second Antinode of the reflective metal electrode
    Applied Physics Letters, 2006
    Co-Authors: Chun-liang Lin, Ting-yi Cho, Chih-hao Chang
    Abstract:

    Due to generally low conductivity and low carrier mobilities of organic materials, organic light-emitting devices (OLEDs) are typically optimized for light outcoupling by locating emitters around the first Antinode of the metal electrode. In this letter, by utilizing device structures containing conductive doping, we investigate theoretically and experimentally the influences of the location of emitters relative to the metal electrode on OLED emission, and show that substantial enhancement in light outcoupling (1.2 times) or forward luminance (1.6 times) could be obtained by placing emitters around the second Antinode instead of the first Antinode. Depending on the detailed condition, the second-Antinode device may also give more directed emission as often observed in strong-microcavity devices yet without suffering a color shift with viewing angles.

Kyriacos C Nicolaou - One of the best experts on this subject based on the ideXlab platform.

Ivett A. Leyva - One of the best experts on this subject based on the ideXlab platform.

  • The Response of Cryogenic H2/O2 Coaxial Jet Flames to Acoustic Disturbances (POST PRINT)
    2015
    Co-Authors: David Forliti, Ivett A. Leyva, Alireza Badakhshan, Jeffrey L Wegener, Douglas G Talley
    Abstract:

    Abstract : An experimental study has been conducted to explore the coupling between a coaxial gaseous hydrogen / liquid oxygen jet flame and transverse acoustic perturbations. A variety of chamber conditions including acoustic frequency, amplitude, and the location of the pressure node / Antinode with respect to the flame were examined. The flame response was documented using high-speed imaging including backlit visualization and unfiltered chemiluminescence. Dynamic mode decomposition was used to isolate the spatial structure of the flame response at the forcing frequency. The results indicate that the flame response to forcing is qualitatively similar to previous results of nonreacting coaxial jet flows; the pressure node forcing appears to generate in-plane flapping of the flame while pressure Antinode forcing induces a helical structure in the flame.

  • The Response of Cryogenic H2/O2 Coaxial Jet Flames to Acoustic Disturbances
    53rd AIAA Aerospace Sciences Meeting, 2015
    Co-Authors: David Forliti, Ivett A. Leyva, Alireza Badakhshan, Jeffrey L Wegener, Doug Talley
    Abstract:

    An experimental study has been conducted to explore the coupling between a coaxial gaseous hydrogen / liquid oxygen jet flame and transverse acoustic perturbations. A variety of chamber conditions including acoustic frequency, amplitude, and the location of the pressure node / Antinode with respect to the flame were examined. The flame response was documented using high-speed imaging including backlit visualization and unfiltered chemiluminescence. Dynamic mode decomposition was used to isolate the spatial structure of the flame response at the forcing frequency. The results indicate that the flame response to forcing is qualitatively similar to previous results of nonreacting coaxial jet flows; the pressure node forcing appears to generate in-plane flapping of the flame while pressure Antinode forcing induces a helical structure in the flame.

  • Cryogenic High-Pressure Shear-Coaxial Jets Exposed to Transverse Acoustic Forcing
    50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012
    Co-Authors: Sophonias Teshome, Ivett A. Leyva, Douglsa Talley, Ann Karagozian
    Abstract:

    Abstract : This experimental study investigated the response of dynamic flow structures of cryogenic coaxial nitrogen jets to pressure perturbations due to transverse acoustic forcing at a pressure Antinode (PAN). The role of injector exit geometry on the flow response was examined using two shear coaxial injectors with different outer-to-inner jet area ratios. Flow conditions for varying outer-to-inner jet momentum flux ratios (0.5 - 20), and acoustic pressure Antinode at the jet axis location, under subcritical (reduced pressure of 0.44) chamber pressures were considered. Dark-core length measurements of the dense inner jet were used to indicate the extent of mixing under different flow conditions and exit geometries. A basic application of proper orthogonal decomposition on the intensity fluctuation of high-speed images enabled the extraction of the spatial and temporal characteristics of the dominant flow structures that existed in the flow field during exposure to acoustic forcing. Regardless of injector geometry or pressure regime, low outer-to-inner momentum flux ratio flows were found to be responsive to acoustic pressure Antinode forcing. With increasing momentum flux ratio, however, the flow response to forcing depended on the injector geometry.

  • Proper Orthogonal Decomposition Analysis of Shear-Coaxial Injector Flows with and without Transverse Acoustic Forcing
    2011
    Co-Authors: Sophonias Teshome, Ivett A. Leyva, Douglas Talley
    Abstract:

    Abstract : This experimental study investigated the response of dynamic flow structures of cryogenic coaxial nitrogen jets to pressure perturbations due to transverse acoustic forcing at a pressure Antinode (PAN). The role of injector exit geometry on the flow response was examined using two shear coaxial injectors with different outer-to-inner jet area ratios. Flow conditions spanning subcritical (reduced pressure of 0.44) to supercritical (reduced pressure of 1.05) chamber pressures, varying outer-to-inner jet momentum flux ratios (0.5 - 20), and acoustic pressure Antinode at the jet axis location were considered. A basic application of proper orthogonal decomposition on the intensity fluctuation of high-speed images enabled the extraction of the spatial and temporal characteristics of the dominant flow structures that existed in the flow field during exposure to acoustic forcing. Regardless of injector geometry or pressure regime, low outer-to-inner momentum flux ratio flows were found to be responsive to acoustic pressure Antinode forcing. With increasing momentum flux ratio, however, the flow response to forcing depended on the injector geometry.

Alessandro Torrielli - One of the best experts on this subject based on the ideXlab platform.

  • hopf algebra structure of the ads cft s matrix
    Physical Review D, 2006
    Co-Authors: Jan Plefka, Fabian Spill, Alessandro Torrielli
    Abstract:

    We formulate the Hopf algebra underlying the su(2/2) world sheet S-matrix of the AdS{sub 5}xS{sup 5} string in the AdS/CFT correspondence. For this we extend the previous construction in the su(1/2) subsector due to Janik to the full algebra by specifying the action of the coproduct and the antipode on the remaining generators. The nontriviality of the coproduct is determined by length-changing effects and results in an unusual central braiding. As an application we explicitly determine the antiparticle representation by means of the established antipode.

Jeanlouis Pinault - One of the best experts on this subject based on the ideXlab platform.

  • resonantly forced baroclinic waves in the oceans subharmonic modes
    Journal of Marine Science and Engineering, 2018
    Co-Authors: Jeanlouis Pinault
    Abstract:

    The study of resonantly forced baroclinic waves in the tropical oceans at mid-latitudes is of paramount importance to advancing our knowledge in fields that investigate the El Nino–Southern Oscillation (ENSO), the decadal climate variability, or the resonant feature of glacial-interglacial cycles that are a result of orbital forcing. Indeed, these baroclinic waves, the natural period of which coincides with the forcing period, have a considerable impact on ocean circulation and in climate variability. Resonantly Forced Waves (RFWs) are characterized by Antinodes at sea surface height anomalies and nodes where modulated geostrophic currents ensure the transfer of warm water from an Antinode to another, reflecting a quasi-geostrophic motion. Several RFWs of different periods are coupled when they share the same node, which involves the geostrophic forces at the basin scale. These RFWs are subject to a subharmonic mode locking, which means that their average periods are a multiple of the natural period of the fundamental wave, that is, one year. This property of coupled oscillator systems is deduced from the Hamiltonian (the energy) of the Caldirola–Kanai (CK) oscillator. In this article, it is shown how the CK oscillator, which is usually used to develop a phenomenological single-particle approach, is transposable to RFWs. Subharmonic modes ensure the durability of the resonant dissipative system, with each oscillator transferring as much interaction energy to all the others that it receives periodically.

  • Resonantly Forced Baroclinic Waves in the Oceans: Subharmonic Modes
    MDPI AG, 2018
    Co-Authors: Jeanlouis Pinault
    Abstract:

    The study of resonantly forced baroclinic waves in the tropical oceans at mid-latitudes is of paramount importance to advancing our knowledge in fields that investigate the El Niño–Southern Oscillation (ENSO), the decadal climate variability, or the resonant feature of glacial-interglacial cycles that are a result of orbital forcing. Indeed, these baroclinic waves, the natural period of which coincides with the forcing period, have a considerable impact on ocean circulation and in climate variability. Resonantly Forced Waves (RFWs) are characterized by Antinodes at sea surface height anomalies and nodes where modulated geostrophic currents ensure the transfer of warm water from an Antinode to another, reflecting a quasi-geostrophic motion. Several RFWs of different periods are coupled when they share the same node, which involves the geostrophic forces at the basin scale. These RFWs are subject to a subharmonic mode locking, which means that their average periods are a multiple of the natural period of the fundamental wave, that is, one year. This property of coupled oscillator systems is deduced from the Hamiltonian (the energy) of the Caldirola–Kanai (CK) oscillator. In this article, it is shown how the CK oscillator, which is usually used to develop a phenomenological single-particle approach, is transposable to RFWs. Subharmonic modes ensure the durability of the resonant dissipative system, with each oscillator transferring as much interaction energy to all the others that it receives periodically