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  • 1
    Digitale Medien
    Digitale Medien
    Resonance effects of diabatic surface crossing within the torsional spectrum of 9-(N-carbazolyl) anthracene observed by supersonic jet fluorescence spectroscopy (1993)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 98 (1993), S. 2580-2592 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: Using the supersonic jet technique and laser-induced fluorescence spectroscopy, the ground and excited state surface of isolated 9-(N-carbazolyl) anthracene (C9A) is investigated. Ground and excited state torsional potentials of high accuracy are deduced from excitation and fluorescence spectra, considering characteristic patterns of Franck–Condon factors within the dispersed fluorescence. S0 exhibits a very flat double minimum potential (equilibrium twist angle 77.5°, barrier 17 cm−1); the barrier for perpendicularity in S1 is approximately 1050 cm−1 and the equilibrium angle is shifted towards coplanarity (64°). An unusual intensity profile of the long progression found in the fluorescence excitation spectrum is ascribed to a resonant nonradiative decay channel within the excited state surface. State selective fluorescence decay rates vs excess vibrational energy confirm this resonant relaxation process. This uncommon observation leads to a model of diabatic surface crossing along the torsional coordinate where the crossing "dark'' state is discussed as a predicted charge transfer state or a higher lying triplet state, mediating further electronic relaxation. Although extended intermolecular vibrational redistribution (IVR) is present in the fluorescence spectra from high vibrational levels, this process is of secondary importance for the resonant nonradiative relaxation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.464140
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  • 2
    Digitale Medien
    Digitale Medien
    Torsional band assignment and intramolecular twist potential of 9,9'-bianthryl and its 10-cyano derivative in a free jet (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 4543-4555 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: Using a pulsed supersonic beam and laser-induced fluorescence spectroscopy the torsional structure of the S0 and S1 states of 9,9'-bianthryl (BA) and its derivative 10-(cyano)-9,9'-bianthryl (CBA) was investigated. Taking into account the very different equilibrium positions of the S0 and S1 potentials which result in a nonobservable 0–0 transition within the jet spectra, a new and straightforward procedure of torsional band assignment is carried out. This is based on a characteristic pattern of Franck–Condon factors within the dispersed fluorescence spectra. The torsional potentials were determined by a fit procedure of a one-dimensional model to the experimental data. The results show that the S1 double minimum potential for BA is shallower than for CBA indicating a stronger interaction between the molecular halfs of the latter compound. The observed rotational contours of torsional bands recorded for CBA reflect the change from a symmetric top molecule (for states above the S1 torsional barrier) to an asymmetric top (for states below the barrier) and manifest the tunneling splitting of the level just below the barrier. The dispersed fluorescence spectra of CBA are discussed in terms of intramolecular vibrational redistribution (IVR) processes. The measured fluorescence decay rates as a function of excess vibrational energy of CBA reflect a saturation behavior already within the origin region in contrast to BA (saturation near 380 cm−1). This is tentatively ascribed to a low lying dark background state possibly of charge transfer character.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.458695
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  • 3
    Digitale Medien
    Digitale Medien
    Anthropogenic influence on the distribution of tropospheric sulphate aerosol (1992)
    [s.l.] : Nature Publishing Group
    Nature 359 (1992), S. 712-716 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] We use the three-dimensional Eulerian transport model MOGUNTIA5 in our calculations. This is based on monthly mean meteorological data and covers the global troposphere with a horizontal resolution of 10° longitude by 10° latitude, and with 10 vertical layers between the surface and 100 ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/359712a0
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  • 4
    Digitale Medien
    Digitale Medien
    Potentiality of the photothermal surface-displacement technique for precisely performed absorption measurement of optical coatings (1994)
    Springer
    Applied physics 58 (1994), S. 377-383 
    Details
    ISSN: 1432-0630
    Schlagwort(e): 78.20.Nv ; 42.78.Hk ; 68.35.Gy ; 68.45.Nj
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract The influence of sample properties on the measured signal has to be investigated, so that measurements of the optical absorption in thin-film coatings by means of the photothermal surface-displacement technique may be precisely performed. Carrying out simultaneously absorption measurements on metal coatings at λ=10.6 μm by using laser calorimetry as well as the surface-displacement technique, the aforementioned influence and the validity of assumptions of the theoretical model, respectively, can be proven. It can be demonstrated that, in contrast to the model, thermophysical coating properties contribute to the probed surface displacement.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00323613
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  • 5
    Digitale Medien
    Digitale Medien
    Licht- und elektronenmikroskopische sowie cytometrische Untersuchungen an peripheren Nerven beim Morbus Tangier (1979)
    Springer
    Acta neuropathologica 45 (1979), S. 53-59 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Tangier disease ; Peripheral nerve ; Electron microscopy ; Cytometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A sural nerve biopsy was performed in a 55-year-old male patient with Tangier disease (familiallipoprotein deficiency). Light-microscopy showed an increase in the endoneural connective tissue and a loss of nerve fibers indicating a chronic peripheral neuropathy. Electron-microscopy revealed an accumulation of lipid droplets within Schwann cells of myelinated and unmyelinated nerve fibers. When compared with age-matched controls the myelinated fiber density was reduced with a relative preponderance of small myelinated fibers. In addition, distributional cytometric studies of nerve vibers in relation to the perineurium and endoneurial capillaries showed: Contrary to 4.6–7.5 μm thick nerve fibers, which accumulated in the center of the nerve fascicle, small (0.5–4.5 μm) and large (7.6–10.0 μm) fibers lay nearby the perineurium. The measured increase in small myelinated nerve fibers around endoneurial capillaries may be explained as a sign of regeneration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00691805
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  • 6
    Digitale Medien
    Digitale Medien
    Reactivity patterns of nerve cell-glia-complexes in mice during pentylenetetrazole-induced seizures. Cytometric-cytophotometric studies (1978)
    Springer
    Acta neuropathologica 43 (1978), S. 243-250 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Epileptic seizures ; Cytometry and cytophotometry ; Nerve cell-glia-complexes ; Mice
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The relationships between nerve cell-glia-complexes (NGCs) and surrounding capillaries were studied by combined cytometric-cytophotometric methods in male mice up to 60 min after injection of 70 mg/kg of pentylenetetrazole (PTZ). The nuclear area in neurons from cortical layers IV and V of the motoric area 8 increased by 13%, and in neurons from the hypoglossal nucleus there was an increase of 23%, associated with phasic changes in the nuclear area of their glial satellites. The number of perfused capillaries increased in both brain regions and there was a 20%-elongation of erythrocyte-filled capillary segments. The cytoplasmic RNA content enlarged in the hypoglossal neurons but decreased in cortical neurons from area 8. Peptidergic neurons and their glial satellites (supraoptic nucleus) showed nuclear shrinkage. Fifty percent of these peptidergic neurons reacted by reduction of their cytoplasmic RNA content. The measured cell reactions seem to be specific for different groups of NGCs which were defined by their histotopography, their neuronal interconnections, and a prevalence of secretory or nonsecretory neurons.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00691585
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  • 7
    Digitale Medien
    Digitale Medien
    Familial centronuclear myopathy: A haploid DNA disease? (1979)
    Springer
    Acta neuropathologica 46 (1979), S. 209-214 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Centronuclear myopathy ; Nuclear DNA of muscle fibres ; Cytophotometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In the same family three boys (ages 8, 11, 14 years), suffering from a slowly progressive weakness of the flexors of the head and distal muscle groups of the extremities, were found to have a myopathy characterized by the presence of central nuclei in type I fibres. Their mother showed no histopathologic signs but a myopathic pattern on electromyography could be demonstrated. Cytophotometric examination of the anterior tibial muscle of these siblings revealed a reduction in DNA content by 50% in the central and subsarcolemmal nuclei (haploid DNA content) when compared with subsarcolemmal nuclei (diploid DNA content) of the same muscle of their mother. Nuclear DNA concentration in fibrocytes did not differ significantly between members of the family. Therefore, it is assumed that the nuclei of muscle fibres are selectively affected by the disease process which is indicated by a haploid DNA content.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00690846
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  • 8
    Digitale Medien
    Digitale Medien
    Investigation of hyperfine structure and isotope shift of the 605.5 nm-line of Lu176 by laser spectroscopy (1979)
    Springer
    The European physical journal 290 (1979), S. 123-126 
    Details
    ISSN: 1434-601X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Using a tunable single mode dye laser the hyperfine structure of the transition 5d6s 2 2 D 5/2 — 5d6s6p 4 F 5/2 has been investigated for the Lu-isotopes Lu175 and Lu176. From our measurements the following values for the hyperfine constantsA andB could be deduced Lu176 5d6s6p 4 F 5/2:A=698.4 (0.4) MHz,B=1,564 (10) MHz 5d6s 2 2 D 5/2:A=104.1 (0.3) MHz.B=2,631 (6) MHz Lu175 5d6s6p 4 F 5/2:A=987.2(0.4) MHz,B=1,117(6) MHz. The isotope shift between the line centers has been determined to be IS(176-175, 605.5 nm)=−420(10) MHz.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01408105
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  • 9
    Digitale Medien
    Digitale Medien
    Ozone measurements from the Balloon Intercomparison Campaign (1990)
    Springer
    Journal of atmospheric chemistry 10 (1990), S. 181-218 
    Details
    ISSN: 1573-0662
    Schlagwort(e): Ozone ; intercomparison ; balloon ; stratosphere
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Geologie und Paläontologie
    Notizen: Abstract Measurements of the Balloon Intercomparison Campaign (BIC), conducted during fall, 1982 (BIC-1) and summer, 1983 (BIC-2), are reported. Results of five remote and two in situ techniques agree (with a few exceptions) within 95% confidence level uncertainties and generally within 15% above 20 km. Weighted mean profiles, which best represent conditions during the capaign, are used as a comparison standard. Accuracies of experiments indicated by BIC generally confirm estimated uncertainites for ECC sondes, UV photometry, and microwave emission experiments, are somewhat better for far IR emission and IR absorption experiments, and are somewhat worse for IR emission and solar UV absorption experiments. The large collection of BIC measurements confirms a problem reported earlier with current theoretical modeling of ozone near 40 km where transport is negligible and the chemistry is believed to be simpler.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00054856
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  • 10
    Digitale Medien
    Digitale Medien
    Investigation of autoionizing CuI-states in the region of the second ionization limit CuII 3d 94s (1992)
    Springer
    The European physical journal 23 (1992), S. 115-119 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 32.80.Dz ; 32.80.Fb ; 32.80.Rm
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The combination of collisional and laser excitation was used for the investigation of autoionizing CuI states in the region of the second ionization limit CuII 3d 9 4s at 85000–95000 cm−1. The analysis of the complicated signal structure was concentrated on the first measurement of CuI 3d 9 4p 2 levels. The experimental results are compared with Hartree-Fock calculations of the energy values and level widths of the autoionization resonances.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01436732
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