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  • 1990-1994  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Fabrication of an organic superlattice film by molecular beam deposition (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 2826-2830 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A superlattice film of 5, 10, 15, 20 tetraphenylporphyrin (H2TPP; C44H30N4) and 5, 10, 15, 20 tetraphenylporphyrinato zinc (ZnTPP; C44H28N4Zn) was grown on a hydrogen terminated surface of Si (100) wafer which was kept at −25 °C. The organic molecular beam deposition technique was used for the fabrication under ultrahigh vacuum between 3×10−9 and 3×10−10 Torr. The small angle x-ray diffraction study has revealed that the period of the superlattice was 4.4 nm, which was also confirmed by the oscillation of the same period observed in a secondary ion mass spectrometry depth profile of Zn. The Fourier-transform infrared spectroscopy measurement indicated that the quasi-planar molecules of H2TPP and ZnTPP were inclined at an angle of 70° with respect to the substrate surface. The film surface was very flat and any roughness could not be detected by field emission secondary electron microscope observation. An atomic force microscope (AFM) therefore was used to investigate the surface. The root mean square roughness calculated from the AFM image was 0.37 nm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353059
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Second-harmonic generation device with integrated periodically domain-inverted regions and distributed Bragg reflector in a LiNbO3 channel waveguide (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 1934-1936 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We propose a new structure of LiNbO3 guided wave second-harmonic generation device, in which the fundamental light beam is sufficiently confined by two distributed Bragg reflectors (DBRs) formed at input and output ports. The 40% increase in the conversion compared with a conventional device without DBR was achieved under a quasi-phase matching condition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.105050
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Product-selective electroreduction of 2,3,4,5,6-pentafluorobenzoic acid to 2,3,5,6-tetrafluorobenzyl alcohol and 2,3,5,6-tetrafluorobenzaldehyde in a flow cell system (1992)
    Springer
    Journal of applied electrochemistry 22 (1992), S. 1082-1086 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract 2,3,4,5,6-Pentafluorobenzoic acid was found to be reduced product-selectively to either 2,3,5,6-tetrafluorobenzyl alcohol or 2,3,5,6-tetrafluorobenzaldehyde at a lead cathode in dilute sulphuric acid containing small amounts of a quaternary ammonium salt. A preliminary optimization of electrolytic conditions for production of either 2,3,5,6-tetrafluorobenzyl alcohol or 2,3,5,6-tetrafluorobenzal dehyde was systematically performed using a laboratory-scale flow-cell system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01029589
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of histamine, granulocyte colony-stimulating factor and db-cAMP on the differentiation of HL-60 cells (1990)
    Springer
    Inflammation research 30 (1990), S. 240-242 
    Details
    ISSN: 1420-908X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Histamine (10−7 to 10−3 M) dose-dependently decreased the incorporation of3H-thymidine into HL-60 cells, starting from the third day of culture. Also, histamine 1 μM significantly induced the differentiation of HL-60 into cells having the morphological characteristics of mature neutrophils, as did db-cAMP and granulocyte colony-stimulating factor (G-CSF). Phosphorylation of proteins appeared at 60 kd and 120 kd and was enhanced upon differentiation of the HL-60 cells treated with histamine, while that of 34 kd was diminished. The phosphorylation profiles induced by G-CSF and db-cAMP were similar to that of histamine. In the case of db-cAMP, however, no phosphorylated band appeared at 120 kd.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01969049
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Preparation and characterization of organic superlattice thin films grown on hydrogenated silicon single-crystal substratesPaper presented at ECASIA 93, Catania, Sicily. 4-8 October 1993. (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 21 (1994), S. 356-364 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: We have succeeded in preparing very thin (nanometre order) alternating layers that can be called ‘organic superlattices’ by using a special combination of materials, substrates and deposition conditions with good verification by various characterization techniques.Specially surface-treated single-crystal silicon substrates with hydrogen-terminated dangling bonds on the surface were used to induce van der Waals heteroepitaxial growth. Choice of materials with the appropriate molecular shapes and aggregation force is also important for preparing flat molecular films. Tetraphenylporphyrins (H2TPP and ZnTPP) and phthalocyanines were used for this purpose. A molecular beam epitaxy chamber with specially designed cells was used with the cooled substrates.Direct proof of the alternating composition was given by transmission electron microscopy observation, avoiding decomposition by the electron beam, and also by SIMS depth profiling under special conditions to ensure good depth resolution. X-ray diffraction in the small-angle region gives the periodicity of the alternating layers, as well as their crystal quality. Atomic force microscopy confirms the atomic flatness and also gives the molecular orientation in the films. Fourier transform infrared spectroscopy examines the chemical stability of the compounds during deposition and also gives the axial orientation of the molecules in the films.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740210606
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    Paper (German National Licenses)
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