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  • 1
    ISSN: 1434-601X
    Keywords: 25.70.Gh ; 25.70.Jj ; 25.70.Lm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract For the violent collisions of 27 MeV/nucleon40Ar with Ag, coincidence measurements have been made between heavy residues and intermediate mass fragments (3≦Z≦14) or light charged particles. From the analysis of the correlation between heavy residues (mass and velocity) and intermediate mass fragments, the main characteristics of the dominant mechanisms, fusion and partially damped collisions preceded or accompanied by a preequilibrium emission, are presented. Balances concerning mean values of parallel linear momentum, mass and atomic number, are established and confirm that a complete description of violent collisions was obtained. Then thermalization is discussed, first in terms of excitation energies derived from kinematics between heavy residues and intermediate mass fragments, and secondly in terms of initial temperature estimates derived from light charged particle spectra. Very hot nuclei (T⋍5.7–6.6 MeV) are produced over a large impact parameter range from very central collisions to medium peripheral ones. Various experimental results are compared to predictions obtained with semi-classical calculations (Landau-Vlasov equation). From their good agreement one may conclude that, depending on the impact parameter, thermal equilibrium is achieved within 4–10×10−22 s.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1434-601X
    Keywords: 25.70.Gh ; 25.70.Jj ; 25.70.Pq
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In a multidetector experiment on 26 or 30 AMeV32S+58Ni, up to four coincident heavier or intermediate-mass fragments were observed. One of these occasionally has the characteristics of a projectile-like fragment, up to three may be attributed to the decay of the heavy reaction product. Taking the velocity of the fragments as a measure of the heavy-product excitation energy, one finds evaporation, fission and multifragmentation to follow one another with rising excitation. Model simulations of sequential decay with up to two binary fissions and, alternatively, of simultaneous statistical multifragmentation were performed for comparison with experimental distributions of mass, velocity and (for events with three slow intermediate-mass fragments) relative azimuthal angle. Though in the three-fragment events indications of simultaneous multifragmentation are present, the sequential binary decay predominates. Evaporated protons and α particles detected in coincidence have a mean multiplicity growing with excitation energy, while the temperature governing the spectra has a plateau with a value of about 5.5 MeV.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 248 (1941), S. 269-275 
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Kohlenoxydverbindungen des Rheniums, die Halogenopentacarbonyle wie das reine dimere Pentacarbonyl, erweisen sich der CO-Substitution durch Pyridin oder o-Phenanthrolin zugänglich, wie dies schon früher bei den Metallen der Eisen- und Chromgruppe aufgedeckt wurde. Die aminsubstituierten Rheniumcarbonyle enthalten sämtlich noch wenigstens 3 Mol CO pro Rheniumatom, d.h.es werden stets nur 2Mol CO durch 2Mol Pyridin oder 1 Mol o-Phenanthrolin ersetzt: ReHal(CO)3Pyr2 nnd ReHal(CO)3 Phthrl sowie Re(CO)3Pyr2 und Re(CO)3, Phthrl2; letztere sind eventuell dimer wie das Rheniumpentacarbonyl. Die aminsubstituierten Rheniumcarbonyle erinnern bezüglich ihrer Entstehungsweise, ihres Baus und ihrer großen Beständigkeit durchaus an die aminsubstituierten Carbonyle der Chromgruppe.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 248 (1941), S. 256-268 
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nachdem die Bemühungen, durch Hochdrucksynthese aus metallischem Rhenium oder durch weitere Reaktionen der Halogenopentacarbonyle reines Rheniumcarbonyl zu erhalten, unter verschiedensten Bedingungen erfolglos blieben, wurde gefunden, daß oxydische Rheniumverbindungen, insbesondere Re2O7 oder auch ReO4K u. a. unter höherem CO-Druck und bei höherer Temperatur direkt halogenfreies, reines Rheniumcarbonyl liefern. Über den Reaktionsmechanismus der einfach zu formulierenden Umsetzungen werden verschiedene Vorstellungen entwickelt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 248 (1941), S. 243-255 
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Im Anschluß an die Auffindung der Halogenopentacarbonyle des Rheniums Re(CO)5Halg, über die früher berichtet wurde, wird das Bildungsbestreben dieser Verbindungen genauer untersucht. Es zeigt sich, daß sie bereits unter wesentlich milderen Bedingungen aus Rheniumhalogeniden entstehen, und zwar nimmt die Bildungstendenz in der Reihe Chlorid → Bromid → Jodid zu. Letzteres erhält man bereits im Kohlenoxydstrom bei gewöhnlichem Druck aus ReJ6K2, für Bromid und Chlorid, aus Komplexen oder normalen Rheniumhalogeniden, empfiehlt sich die Anwendung eines geringen Überdrucks von 10 bzw. 30 at Kohlenoxyd. Insgesamt ist für die Entstehung der Halogenopentacarbonyle weniger die Höhe des CO-Drucks als die Temperatur (200-230°) maßgebend.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 26 (1998), S. 306-315 
    ISSN: 0142-2421
    Keywords: polycarbonate ; SF6 ; plasma ; XPS, SFM ; AFM ; mass spectroscopy ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A systematic investigation was made of the chemical and morphological influences of SF6 plasma on polycarbonate and the influence of plasma treatment on Al metallization. Mass and ion spectroscopy were used for characterization of the plasma and the etching process. X-ray photoelectron spectroscopy (XPS) measurements were applied for the chemical characterization, while atomic force microscopy (AFM) (static and dynamic mode) served to inspect the surface morphology. All analytical techniques were performed in an ultrahigh vacuum system, in order to prevent the polycarbonate sample from being exposed to ambient air after the plasma treatment. During the etching process we used mass difference spectra to demonstrate the removal of masses 19, 28 and 32 corresponding to HF, CO (N2) and CF. Additionally, the inclusion of fluorine was also observed by this technique.The XPS spectra of polycarbonate surfaces show a significant inclusion of fluorine (C-F, C-F2) and a reduction of the oxygen content after the plasma treatment. Aluminium metallization leads to the formation of an Al-F interlayer; metallic growth of Al is only observed when the metallic layers become thicker than a few nanometres.The AFM investigations have shown that even a short plasma treatment causes changes in morphology (structures with an extension of 20-40 nm). After extended plasma exposure the surface becomes very rough, resulting in poor Al adhesion. On untreated polycarbonate, Al grows in the form of weakly bound clusters, which can only be imaged in the dynamic AFM mode. After plasma treatment, Al grows in the form of well-adhering flat layers without clustering. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 23 (1995), S. 416-425 
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Atomic force microscopy (AFM) is applied on two different types of thin latex films. Polystyrene dispersion particles are prepared by various methods to form well-ordered monolayers and multilayers. Atomic force microscopy serves as a tool to study the surface structures of such films and to find the optimal preparation conditions. The micromorphology of the second system, an adhesive tape, was imaged successfully by AFM running in dynamic mode. Besides the morphological studies, the interaction between the sticky surface and the AFM tip is measured by the damping of the cantilever oscillation versus tip-sample distance.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 45 (1962), S. 261-270 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The authors describe a technique which allows the direct transfer of the results of thin-layer chromatography or paper chromatography to preparative scale separations: a horizontal column is made using finely powdered adsorbents (silica gel, alumina, or cellulose powder) in a cellophane tube which can be cut into slices after development.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 23 (1940), S. 676-683 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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