Search Results - (Author, Cooperation:D. S. Ko)

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  1. 1
    Staff View
    Publication Date:
    2015-05-08
    Publisher:
    Nature Publishing Group (NPG)
    Print ISSN:
    0028-0836
    Electronic ISSN:
    1476-4687
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Latest Papers from Table of Contents or Articles in Press
  3. 3
    Staff View
    ISSN:
    1432-0649
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Physics
    Notes:
    Abstract.  Using a confocal microscope with a single-photon avalanche photodiode as detector, we studied photon bursts of single Rhodamine 6G (R6G) and Rhodamin B-zwitterion (RB) molecules in aqueous solution by excitation of the lowest excited singlet state S 1 with a frequency-doubled titanium:sapphire laser. Multichannel scaler traces, the fluorescence autocorrelation function and fluorescence decay times determined by time-correlated single-photon counting have been measured simultaneously. The time-resolved fluorescence signals were analyzed with a maximum likelihood estimator. Fluorescence lifetime patterns in steps of 100 ps were generated by convolution with the excitation pulse. The lifetime of the S 1 state was derived from the Kullback-Leibler minimum discrimination information. We are able to demonstrate for the first time identification of two different single dye molecules via their characteristic fluorescence lifetimes of 1.79±0.33 ns (RB) and 3.79±0.38 ns (R6G) in aqueous solution.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses
  4. 4
    Staff View
    ISSN:
    1432-0649
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Physics
    Notes:
    Abstract Using a confocal microscope with a single-photon avalanche photodiode as detector, we studied photon bursts of single Rhodamine 6G (R6G) and Rhodamin B-zwitterion (RB) molecules in aqueous solution by excitation of the lowest excited singlet stateS 1 with a frequency-doubled titanium: sapphire laser. Multichannel scaler traces, the fluorescence autocorrelation function and fluorescence decay times determined by time-correlated single-photon counting have been measured simultaneously. The time-resolved fluorescence signals were analyzed with a maximum likelihood estimator. Fluorescence lifetime patterns in steps of 100 ps were generated by convolution with the excitation pulse. The lifetime of theS 1 state was derived from the Kullback-Leibler minimum discrimination information. We are able to demonstrate for the first time identification of two different single dye molecules via their characteristic fluorescence lifetimes of 1.79 ± 0.33 ns (RB) and 3.79 ± 0.38 ns (R6G) in aqueous solution.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses
  5. 5
    Dietrich, D. E. ; Lin, C. A. ; Mestas-Nunez, A. ; Ko, D. S.
    Springer
    Published 1997
    Staff View
    ISSN:
    1436-5065
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Geography
    Physics
    Notes:
    Summary The Gulf of Mexico (GOM) circulation is simulated using the DieCAST ocean model, with a horizontal resolution of 1/12° and 20 vertical layers. The results compare well with observations of both large and small scale features, including Loop Current frontal occlusions associated with frontal eddies. The simulation is carried out without any data assimilation. The frontal eddies tend to be spaced at about 90° intervals around the Loop Current, leading to a Loop Current head shaped like a square with rounded corners. The pattern rotates as the eddies circle the Loop, and frontal eddies elongate as they squeeze through the Florida Strait. Major warm core eddies separate regularly from the Loop Current and propagate to the western GOM. Old warm core eddies in the western Gulf dissipate through bottom drag effects, which also generate cyclonic parasitic eddies. Newly arrived warm core eddies merge with old ones in the western GOM. Recently separated elongated Loop Current eddies can rotate and reattach temporarily to the Loop Current. The barotropic flow component develops eddies between the main separated warm core eddy and the Loop Current due to eastward dispersion, as the main eddy itself propagates westward into the Gulf.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses