Search Results - (Author, Cooperation:A. Nebel)

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  1. 1
    Staff View
    Publication Date:
    2016-01-09
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    Asia ; Chromosome Mapping ; DNA, Bacterial/genetics/isolation & purification ; Europe ; Genome, Bacterial/*genetics ; Helicobacter Infections/*microbiology ; Helicobacter pylori/*genetics/isolation & purification ; Human Migration ; Humans ; *Hybridization, Genetic ; Ice Cover/microbiology ; Mummies/microbiology ; Phylogeny ; Phylogeography ; Sequence Analysis, DNA ; Stomach/*microbiology
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Staff View
    Publication Date:
    2013-06-15
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    Bone and Bones/microbiology ; DNA, Bacterial/chemistry/genetics/isolation & purification ; Denmark ; Endemic Diseases/history ; *Evolution, Molecular ; Genome, Bacterial/*genetics ; Great Britain ; History, Medieval ; Humans ; Leprosy/epidemiology/history/*microbiology ; Mycobacterium leprae/*classification/*genetics/isolation & purification ; Mycolic Acids/chemistry ; Phylogeny ; Sweden ; Tooth/microbiology
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  3. 3
    Albrecht, T. F. ; Sandmann, J. H. H. ; Feldmann, J. ; Stolz, W. ; Göbel, E. O. ; Nebel, A. ; Fallnich, C. ; Beigang, R.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1993
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We present femtosecond four-wave mixing (FWM) experiments on unstrained, thin (InGa)As/InP multiple quantum wells in the spectral region around 1175 nm. These experiments became feasible by employing a stabilized femtosecond optical parametric oscillator which generates tunable 160 fs pulses in the near-infrared. The dephasing time of the heavy-hole exciton is determined to be 1.2 ps at low temperature, corresponding to a homogeneous linewidth of 1.1 meV. In addition, a beating of the FWM signal with a time period of 1.3 ps corresponding to an energy spacing of 3.2 meV is observed. We attribute this to the simultaneous excitation of localized excitons and excitons bound to an impurity or defect, which are not spectrally resolved in the linear optical spectra due to considerable inhomogeneous broadening.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.110609

    Articles: DFG German National Licenses
  4. 4
    Nebel, A. ; Comes, F.J. ; Stephan-Rossbach, K.-H.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0301-0104
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Chemistry and Pharmacology
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0301-0104(85)85081-3

    Articles: DFG German National Licenses
  5. 5
    Staff View
    ISSN:
    0003-2670
    Keywords:
    Gmelin Factual Database ; Information systems
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Chemistry and Pharmacology
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0003-2670(92)85037-7

    Articles: DFG German National Licenses
  6. 6
    Staff View
    ISSN:
    1432-0649
    Keywords:
    42.65.Ky ; 42.60.Fc ; 02.60
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Physics
    Notes:
    Abstract We report on a cw mode-locked non-critically phase matched KTP optical parametric oscillator synchronously pumped by a picosecond Ti:Sapphire laser. High average signal output power of up to 950 mW over a large tuning range has been achieved. For this OPO the influence of resonator-length detuning on the output power, pulse duration and spectral bandwidth has been investigated. The measured data are in good agreement with the results of a numerical simulation using a split-step Fourier method which considers the group-velocity mismatch, the group-velocity dispersion and the self-phase modulation. The numerical simulation also describes the measured strong pump depletion and its influence on the OPO output and efficiency.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF01081322

    Articles: DFG German National Licenses
  7. 7
    Nebel, A. ; Frost, H. ; Beigang, R. ; Wallenstein, R.
    Springer
    Published 1995
    Staff View
    ISSN:
    1432-0649
    Keywords:
    42.65
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Physics
    Notes:
    Abstract Efficient generation of femtosecond pulses in the wavelength range from 520 to 675 nm by external frequency doubling the signal wave of a non-critically phase-matched picosecond KTP Optical Parametric Oscillator (OPO) in a non-critically phase-matched temperature tuned LiB3O5(LBO) crystal is demonstrated. An average power of the second harmonic as high as 310 mW at 575 nm was generated. In the absence of group velocity mismatch of LBO for a wavelength of the OPO at about 1.3 µm the minimum second-harmonic pulse width was 400 fs at 645 nm.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF01081326

    Articles: DFG German National Licenses
  8. 8
    Ruffing, B. ; Nebel, A. ; Wallenstein, R.
    Springer
    Published 1998
    Staff View
    ISSN:
    1432-0649
    Keywords:
    PACS: 42.65.Ky
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Physics
    Notes:
    4 (KTA) optical parametric oscillator (OPO) synchronously pumped by a cw diode-pumped mode-locked Nd:YVO4 oscillator–amplifier system. The laser system (pumped by 84 W of cw 808-nm diode radiation) generates 7-ps-long pulses at 1.064 μm with a repetition rate of 83.4 MHz and an average power of 29 W. The OPO, synchronously pumped by the 1.064-μm laser pulses, consists of a 15-mm-long KTA crystal (cut for type II noncritical phase-matching) in a folded signal resonant linear resonator. The average powers of the 1.54-μm signal radiation and the 3.47-μm idler radiation are 14.6 W and 6.4 W, respectively. The total OPO output of 21 W corresponds to an internal efficiency of 75%. The experimental investigations include measurements of the OPO output power (and its dependence on the pump power, the transmission of the output coupler, and the resonator length) and of the pulse properties (such as pulse duration and spectral width). The measured results are in good agreement with the predictions of a numerical analysis based on a split-step Fourier method.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/s003400050541

    Articles: DFG German National Licenses
  9. 9
    Nebel, A. ; Beigang, R.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0030-4018
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0030-4018(92)90578-F

    Articles: DFG German National Licenses
  10. 10
    Kurobori, T. ; Nebel, A. ; Beigang, R. ; Welling, H.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0030-4018
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0030-4018(89)90173-9

    Articles: DFG German National Licenses
  11. 11
    Petzold, G. ; Nebel, A. ; Buchhammer, H.-M. ; Lunkwitz, K.
    Springer
    Published 1998
    Staff View
    ISSN:
    1435-1536
    Keywords:
    Key words Polyelectrolytes ; pre-formed polyelectrolyte complexes ; flocculation ; sedimentation ; mechanism
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Chemistry and Pharmacology
    Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes:
    Abstract  Polyelectrolyte complexes (PEC) from poly(diallyl-dimethyl-ammoniumchloride) PDADMAC and two different polyanions, formed in aqueous solution, were characterized by different methods (zeta-potential, net content, turbidity) and applied as flocculants. The flocculation of clay was investigated by sedimentation measurement as well as by a dynamic method, using a Fibre Optical Flocculation Sensor. The results of both methods showed that the most important advantages of PEC were the high velocity of sedimentation and a very broad range of the optimum flocculation concentration. In spite of the differences in the complex-forming behavior of the two polyanions used, no significant differences between complexes of the same composition but different polyanions are obtained. In contrast, the ratio of anionic to cationic charges is of great importance for the mechanism of flocculation.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/s003960050219

    Articles: DFG German National Licenses