ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Polymer and Materials Science  (5)
  • Retina
  • Wiley-Blackwell  (5)
  • 1990-1994  (3)
  • 1965-1969  (2)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 3 (1994), S. 33-39 
    ISSN: 1057-9257
    Keywords: High-density luminescence ; Non-linear transmission ; ZnTe ; Metal-organic vapour phase epitaxy ; Inelastic exciton scattering ; Electron-hole plasma ; Pump-and-probe method ; Exciton screening ; Band gap renormalization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: We investigated the high-density luminescence and non-linear transmission of ZnTe layers grown by metal-organic vapour phase epitaxy (MOVPE). For the high-density luminescence we compared ZnTe layers on (001) GaAs substrate with free-standing ZnTe layers of equal thickness. At high excitation intensities a strong luminescence P band appears a few meV below the free exciton energy which is assigned to resonant exciton-scattering processes. A second strong luminescence N band occurs only in free-standing layers. It shows a remarkable red shift with increasing intensity and becomes the dominant emission for an excitation intensity Iexc 〉 1.5 MW cm-2. This lower-energy band was interpreted as electron-hole plasma recombination.The optical non-linearity of thin ZnTe layers in the excitonic region was investigated by pump-and-probe experiments at 2 K and room temperature (RT). For these experiments we used two different pump energies, one above (at 2 K and RT) and one below (at 2 K) the band gap energy. In all cases a red shift and a large non-linear decrease in the excitonic absorption with increasing pump intensity was observed. The experimental results can be explained by many-body effects of exciton screening.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 961-975 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The tensile stress-strain behavior of glass fiber-reinforced polyacetal resin was investigated for various fiber concentrations, fiber length distributions, and finishing agents. The polyacetal fiber blends change considerably in strength and elongation at break when treated with ammonium chloride, but otherwise similar specimens still follow a common stress-strain curve to a point shortly before failure. As the mean fiber length decreases, the modulus and tensile strength fall, but the elongation at break remains almost unchanged. The observed tensile behavior is discussed in terms of a simplified model, which assigns the fibers to two categories: a fraction α parallel to the applied load, and the remainder distributed in a plane perpendicular to the load axis. By fitting this model to the stress-strain curves, two other constants of each system are derived: a length-dependent efficiency factor β for parallel fibers, whose magnitude agrees with the predictions of Rosen and his co-workers, and a factor γ which expresses the constraint of the matrix resin by the “transverse” fibers. The behavior of γ is consistent with Tsai's theory of the transverse modulus of laminates, if a reasonable amount of fiber-fiber contact is assumed. In terms of this model, possible interpretations of the behavior under repeated loading and the mechanism of tensile failure are presented.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 65 (1993), S. 1078-1078 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 65 (1993), S. 1050-1051 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 81 (1965), S. 14-31 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Ein Verfahren zur Bestimmung von Gewichts- und Zahlenmittel des Molekulargewicht von Trioxancopolymeren mit geringem Gehalt an Oxyäthylenbausteinen wurde mit Hilfe von Lichtstreuung und osmotischen Messungen entwickelt. In guter Übereinstimmung mit indirekten Schätzungen über den Effekt von Kettenüberträgern wurde das Verhältnis Mw/Mn für eine Anzahl unfranktionierter Polymerer zu ungefähr 2 bestimmt. Ferner wurden Viskositätsmessungen in verdünnter Lösung und in der Schmelze ausgeführt. Die Schmelzviskosität bei der Schergeschwindigkeit Null ist für einfache Polymere und für Mischungen zweier Polymere ungefähr proportional zu Mw3,4. Die Abhängigkeit der Schmelzviskosität von der Schergeschwindigkeit gehorcht der empirischen BUECHE-HARDING-Gleichung; aber die Werte für MR, die sich mittels dieser Gleichung berechnen lassen, sind viel Kleiner als Mw. In Mischungen sind die MR-Werte größer als diejenigen der Komponenten. Alle Ergebnisse stehen in Übereinstimmung mit Messungen an anderen Polymeren, welche ungefähr dieselbe Molekulargewichtsverteilung besitzen.
    Notes: Methods have been developed for the determination of weight and number average molecular weights of copolymers of trioxane containing oxyethylene units by light scattering and osmotic pressure measurements, respectively. The ratio Mw/Mn for a number of whole polymers is close to 2, in good agreement with the estimate of this ratio indirectly determined from the effect of chain transfer agent. Dilute solution and melt viscosity measurements have also been made. The melt viscosity at zero shear rate is approximately proportional to the 3.4 power of Mw, both for polymers as polymerized and for a blend of two such polymers. The dependence of melt viscosity on shear rate can be fitted to the BUECHE-HARDING emperical equation, but the values of MR calculated from this equation are much smaller than Mw. For the blend MR is higher than that of either component. All of the results are in accord with those found for other polymers of about the same molecular weight distribution.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...