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  • 1
    Electronic Resource
    Electronic Resource
    An improved perturbation approach to the 2D Edwards polymer: Corrections to scaling (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 105 (1996), S. 8951-8957 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We present the results of a new perturbation calculation in polymer statistics which starts from a ground state that already correctly predicts the long chain length behaviour of the mean square end-to-end distance 〈R2N〉, namely, the solution to the two dimensional (2D) Edwards model. The 〈R2N〉 thus calculated is shown to be convergent in N, the number of steps in the chain, in contrast to previous methods which start from the free random walk solution. This allows us to calculate a new value for the leading correction-to-scaling exponent Δ. Writing 〈R2N〉=AN2ν(1+BN−Δ+CN−1+...), where ν=3/4 in 2D, our result shows that Δ=1/2. This value is also supported by an analysis of 2D self-avoiding walks on the continuum. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.472625
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  • 2
    Electronic Resource
    Electronic Resource
    Quasi-reflexivity, weakly unconditionally convergent series and weak compactness (1969)
    Springer
    Mathematische Annalen 182 (1969), S. 45-54 
    Details
    ISSN: 1432-1807
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01350162
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  • 3
    Electronic Resource
    Electronic Resource
    Thermoluminescence and hydroxyl defects associated with broad-band infra red absorption in synthetic quartz (1990)
    Springer
    Physics and chemistry of minerals 17 (1990), S. 27-33 
    Details
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract A study has been made of thermoluminescence from synthetic quartz with varying hydroxyl impurity concentrations up to approximately 300 H/106 Si which are associated with a “broad-band” IR absorption in the range 2600–3700 cm−1. These hydroxyl defects are known to be important in the hydrolytic weakening of quartz. We have found only minor differences in the glow curves of unheated crystals but significant intensity increases when “wet” crystals are heated sufficiently to cause bubble formation. It would seem that the electron traps are unaffected by the bubble formation, but the electron/luminescence centre radiative recombination probability is increased.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209222
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  • 4
    Electronic Resource
    Electronic Resource
    The crystal structures of free radical salts and complexes. VII. [1,2-Di(N-ethyl-4-pyridinium)ethylene]2+(7,7,8,8-tetracyanoquinodimethane)42− (1976)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 32 (1976), S. 2948-2952 
    Details
    ISSN: 1600-5740
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0567740876009345
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  • 5
    Electronic Resource
    Electronic Resource
    Thermoluminescence and Ultra-violet Phosphorescence of the Nucleic Acid Bases (1965)
    [s.l.] : Nature Publishing Group
    Nature 208 (1965), S. 1198-1199 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] (1) Thermoluminescence. The samples were prepared as cylindrical pellets of diameter 1-25 cm and depth 1 mm, formed under pressures of about 4 tons/in2. Following irradiation in silicate glass tubes, in the presence of oxygen, glow curves were recorded using a technique identical to that described ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/2081198a0
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  • 6
    Electronic Resource
    Electronic Resource
    Simultaneous thermally stimulated luminescence and depolarization current in low density polyethylene (1991)
    Springer
    Journal of thermal analysis and calorimetry 37 (1991), S. 1137-1152 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wurden simultane TSL- und TSD-Messungen an 0.175 mm starken, über aufgedampfte Goldelektroden verfügende Polyethylenproben geringer Dichte durchgeführt. Die Proben wurden bei Raumtemperatur und einer Feldstärke von 90 kV/cm gleichstrompolarisiert, auf −190°C abgekühlt, bei noch anliegendem Feld röntgenbestrahlt und dann unter Kurzschluß mit 3 Grad/min erhitzt. Durch einen Vergleich der TSL- und TSD-Daten, insbesondere der Wirkung der Oxydation der Proben bzw. des Eintauchens in rauchende Salpetersäure, zeigten, daß (1) die Raumladungstransport-Komponente des TSD-Stromes zwischen −190 und 30°C vernachlässigbar ist, (2) die Ladungsinjektion bei etwa — 10°C beginnt (für aufgedampfte Goldelektroden) und mit steigender Temperatur schnell anwächst und (3) die gesamte injezierte Ladung durch die Probe hindurch an die gegenüberliegende Elektrode transportiert wird. Ein derartiger Transport erfolgt nur in den amorphen Regionen der Probe.
    Notes: Abstract Thermally stimulated luminescence (TSL) and thermally stimulated depolarization current (TSD) measurements were made simultaneously on low density polyethylene samples 0.175 mm thick, carrying evaporated gold electrodes. The samples were dc-polarized at room temperature at a field strength of 90 kV/cm, cooled to −190°C and X-irradiated with the field still applied, and then heated in short-circuit at 3 deg/min. Comparing the TSL and TSD data, particularly the effects of oxidizing the samples and immersing them in fuming nitric acid, it was shown that (1) the space-charge transport component of the TSD current between −190 and 30°C is negligible, (2) charge injection begins around −10°C (for evaporated gold electrodes) and increases rapidly with increasing temperature, and (3) all the injected charge is transported through the sample to the opposite electrode. Such transport takes place only through the amorphous regions of the sample.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01913850
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  • 7
    Electronic Resource
    Electronic Resource
    Thermally stimulated luminescence and conductivity — Additional tools for thermal analysis of polymers (1990)
    Springer
    Journal of thermal analysis and calorimetry 36 (1990), S. 331-359 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es werden diejenigen physikalischen Erscheinungen umrissen, auf denen Messungen von thermisch stimulierter Lumineszenz und Leitfähigkeit basieren, die logisch als ergänzend zu herrkömmlichen thermoanalytischen Messungen betrachtet werden. Zur Durchführung von Messungen dieser Art benötigte Einrichtungen und Proben werden kurz beschrieben und Grundbegriffe für die Interpretierung der experimentellen Ergebnisse skizziert. Einige frühere experimentelle Daten, die ausgewählt wurden, um die Empfindlichkeit der thermisch stimultierten Lumineszenz und Leitfähigkeit gegenüber Dopen der Probe bzw. Vernäderungen in ihrer Morphologie zu verdeutlichen, werden vorgestellt und diskutiert.
    Notes: Abstract The physical phenomena underlying thermally stimulated luminescence and conductivity measurements, logically considered as complementary to conventional thermal analysis measurements, are outlined. The equipment and samples required to make such measurements are briefly described, and the basic concepts underpinning the interpretation of the data sketched. Some recent experimental data, chosen to reflect the sensitivity of thermally stimulated luminescence and conductivity to doping of the sample and changes in its morphology, are presented and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01912093
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  • 8
    Electronic Resource
    Electronic Resource
    The temperature dependence of space charge accumulation in cross-linked polyethylene (1997)
    Springer
    Journal of thermal analysis and calorimetry 50 (1997), S. 19-31 
    Details
    ISSN: 1572-8943
    Keywords: LIPP ; polyethylene ; space charge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This paper presents the results of laser-induced-pressure-pulse (LIPP) measurements of space charge accumulation in 0.5 mm thick planar XLPE samples with aluminium electrodes, over the temperature range 30–90°C. The applied field strength was 10 kV mm−1. The increase in transit time of the pressure pulse across the sample with increasing temperature indicated that Young's modulus decreased by 50% from 30 to 90°C. It was concluded that electrons injected at the cathode are transported to the anode at temperatures above 40°C, and that electron traps cause an accumulation of negative charge immediately adjacent to both cathode and anode. It appears that a concentration of impurity molecules accumulates close to the cathode, and field-assisted thermal ionisation of these molecules generates an immobile positive space charge adjoining the electronic space charge adjacent to the cathode.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01979546
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  • 9
    Electronic Resource
    Electronic Resource
    Thermoluminescence in poly(methyl methacrylate) γ-irradiated at 77°K (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1283-1296 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Isotactic and atactic poly(methyl methacrylate) containing varying amounts of polymerization initiator and chain-transfer additives, and carefully purified radiation-polymerized material, were γ-irradiated in the dark at liquid nitrogen temperature. On warming to room temperature at a near-linear rate of 20°K./min., a glow peak having a maximum luminescence intensity at 162 ± 8°K. was observed in all samples; an additional peak at 239 ± 7°K. was resolved relatively infrequently. Low luminescence yields precluded an investigation of the spectral distribution of the glow peaks. It is shown that the electron traps associated with the lower temperature peak are most probably the main-chain methyl groups, while the higher temperature glow peak is tentatively associated with escape of electrons from structural defects in a few small crystalline regions of the samples. It is postulated that, for the peak at 162°K., the trapped electrons combine radiatively with luminescence centers when thermally induced rotational motion of the main-chain methyl groups permits sufficient wave-function overlap. Assuming that methods of glow curve analysis proposed for inorganic materials are applicable to organics, first-order recombination kinetics and an activation energy of 0.084 ± 0.006 e. v. are deduced for the intensity maximum at 162°K. This activation energy is in fair agreement with that obtained by Bordoni et al. for an unspecified side-chain motion occurring at similar temperatures, but is only about half the values quoted with some reservations by Powles and by Kawai on the basis of NMR experiments. It was not possible to determine the kinetics of the 239°K. peak with certainty, but an activation energy of 0.432 ± 0.085 e. v. follows from a first-order assumption. The additives present in the samples did not appear to play any significant part as electrontrapping agents; this observation contrasts with some recent work on the visible and ultraviolet absorption spectra of the same materials which showed a close correlation of additional bands developed following irradiation with the presence of specific additives.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060707
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  • 10
    Electronic Resource
    Electronic Resource
    Thermoluminescence and chain-fold morphology in low-density polyethylene (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 25 (1987), S. 1885-1895 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Further thermoluminescence data are presented supporting our earlier suggestion that the electron traps associated with the three peaks in the thermoluminescence glow curve of a low-density polyethylene sample from which absorbed air has been removed are formed by the polymer chains themselves in the chain-fold regions of the samples. These traps are shown to be sensitive to heating of the sample to temperature around its melting point; in particular, the lowest temperature peak disappears if the sample is held at 90°C in vacuum for 5 min. If the sample is maintained in vacuum at room temperature after such treatment, its modified glow curve remains unchanged for a period of at least 7 days; however, if the sample is exposed to air, nitrogen, or argon after such treatment, its gas-free glow curve begins to change within 3 days, evolving toward a three-peak form with the same peak temperatures but with relative intensities different from those observed before heating began. This suggests that the gas molecules “lubricate” the polymer chains, which then begin to move toward new equilibrium configurations. Immersion in n-hexane at room temperature has little effect on the luminescence centers but disables the electron traps. Immersion in fuming nitric acid at room temperature for 2 days appears to destroy the electron traps permanently, as would be expected if the chain folds are digested by the acid; its effect on the luminescence centers is still to be determined.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1987.090250908
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