E. Donth

Universitätsklinikum Halle (Saale), Halle-on-the-Saale, Saxony-Anhalt, Germany

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Publications (79)153.19 Total impact

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    E. Donth
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    ABSTRACT: A DO paper of 2008 is exemplarily commented to demonstrate the general risk that the development of a new paradigm for astroparticle physics can be hindered by the work of large collaborations. This paper allows sharp formulations because only the simplest Higgs variant is treated. PACS numbers: 01.10 Hx, 13.85 Rm, 14.80 Bn Comment: stylistic improvement in second version
    06/2009;
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    E. Donth
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    ABSTRACT: Culminating-point filter construction for particle points is distinguished from torus construction for wave functions in the tangent objects of their neighborhoods. Both constructions are not united by a general manifold diffeomorphism, but are united by a map of a hidden conformal $S^{1}\times S^{3}$ charge with harmonic (Maxwell) potentials into a physical space formed by culminating points, tangent objects, and Feynman connections. The particles are obtained from three classes of eigensolutions of the homogeneous potential equations on $S^{1}\times S^{3}$. The map of the $u(2)$ invariant vector fields into the Dirac phase factors of the connections yields the electro-weak Lagrangian with explicit mass operators for the massive leptons. The spectrum of massive particles is restricted by the small, manageable number of eigensolution classes and an instability of the model for higher mass values. This instability also defines the huge numbers of filter elements needed for the culminating points. Weinberg angle, current coupling constant, and lepton masses are calculated or estimated from the renormalization of filter properties. Consequences for particle astrophysics follow, on the one hand, from the restriction of particle classes and, on the other hand, from the suggestion of new particles from the three classes e.g. of dark matter, of a confinon for the hadrons, and of a prebaryon. Definitely excluded are e.g. SUSY constructions, Higgs particles, and a quark gluon plasma: three-piece phenoma from the confinons are always present. Comment: correction of references in table 1
    01/2009;
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    E. Donth
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    ABSTRACT: A new thermodynamics for liquids related to von Laue's approach (1917) substitutes some particle priors of Gibb's rational thermodynamics. This allows the definition of a new dynamic entity ($G$ defect) whose diffusion properties also claim a largest causal region ($F$ speckle). In the frame of the hidden charge model \cite{this part} it is discussed, whether this new thermodynamics can be applied to an initial liquid for cosmology, where the $G$ defects lead to the later galaxies and the $F$ speckles to a finite expanding universe of diameter $R$. Far below a "hadronic" Compton wave length $\lambda_{0}$ of order 1 fermi, $R\ll \lambda_{0}$, there is no room left for too small filter elements, that would, however, be necessary for a filter convergence to an isolated cold quantum mechanical point particle. When the expansion of the universe comes to $\lambda_{0}$, i.e. for $R\approx \lambda_{0}$, then many hadrons are created. The related negative pressure gets large amounts and leads to an intense hadronic cosmological inflation. -- The $G$ defects are formed by the shaping power of Levy distribution (preponderant component, hierarchy, damping factor). A relation between the number of galaxies, the tilt in the density fluctuation, and the temperature amplitude of the CMB is obtained. For $R\gg \lambda_{0}$ (much vacuum), the "electromagnetic" $M_4$ tangent objects are large and flat. This allows a geometric interpretation of the "stony" dark energy as flatness on the "golden" side of the Einstein equation, $\Omega_{\Lambda}=1-\Omega_{M}$. Comment: short note added in text
    01/2009;
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    E. Donth
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    ABSTRACT: This theoretical paper is to advance a phenomenological, quasi thermodynamic approach to the dynamics of classical liquids which uses the Levy distribution of probability theory. Doubts from the chemical physics community about the application of its unusual properties to this field are tried to be removed. In particular, to understand the preponderant component of the Levy sum for Glarum Levy defects and Fischer speckles, the classical mathematical proof [D. A. Darling, Trans. Amer. Math. Soc. 73, 95 (1952)] for the existence and the influence of this component is accompanied by addition of physical arguments related to these defects. It is tried to explain an underlying fluctuating spatial pattern of free volume with weak contrast and a pattern of mobility with strong contrast, and to explain the characteristic lengths for the main transition and the Fischer modes. The structure of the relaxation chart (dynamic glass transition) and several properties of, and relations between, the slower dispersion zones therein, are reviewed for classical glassforming liquids of moderate complexity. For the main transition, the preponderant component is pushed in the midst of the defect and induces the molecule to its diffusion step across the cage door of the next neighbors. An Experimentum Crucis for an indirect proof of the existence of defects - via characteristic lengths - is also described.
    01/2009;
  • E Donth
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    ABSTRACT: The experimental information about the characteristic length of the dynamic glass transition and its temperature dependence is collected. Extrapolation to the splitting region (several 10 K above Tg) gives a length of very few nanometers. Using arguments from thermodynamic fluctuation theory it is concluded that a sharp kinetic transition temperature Tc > Tg is not possible for such small lengths.
    Physica Scripta 01/2007; 1993(T49A):223. · 1.03 Impact Factor
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    ABSTRACT: Although known for more than thirty years, the physical nature of the glass-transition crossover region is still an open question. Heat capacity spectroscopy experiments in the crossover region of poly(n-hexyl methacrylate) are presented which indicate, for the first time, that the dynamic glass transition consists of two separate parts in series: A thermorheologically rather simple high-temperature part (called a-process) and a low-temperature part with increasing molecular cooperativity on the nanometer scale (α-process). The calorimetric experiments show, surprisingly, a decline of the a process and a separate onset of the α-process.
    EPL (Europhysics Letters) 01/2007; 44(3):321. · 2.26 Impact Factor
  • A. Schönhals, E. Donth
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    ABSTRACT: A new approach to the Andrade law of creep relaxation is given. Starting points are the theory of linear response and the fluctuation-dissipation theorem (FDT). According to the FDT the macroscopic shear complianceis determined by the correlation function of shear angle fluctuation of a functional subsystem. An investigation of the shear pulse response leads to the conclusion that the subsystem must be considered as a temporarily inhomogeneous solid. A dynamical percolation model is developed resulting in a power law for the short-time behavior of creep compliance. The relevant exponent lies between 0.3 and 0.47, definitely lower than 1/2. The experimental value for the Andrade exponent is about 1/3.Ein neuer Zugang zum Andradegesetz der Kriechrelaxation wird vorgestellt. Ausgangspunkte sind die Theorie der linearen Reaktion und das Fluktuations-Dissipations-Theorem (FDT). Die makroskopische Schernachgiebigkeit wird nach dem FDT durch die Korrelationsfunktion der Scherwinkelfluktuationen eines funktionalen Subsystems bestimmt. Eine Untersuchung der Scherimpulsreaktion des Subsystems ergibt, daß das Subsystem als temporr inhomogener Festkörper betrachtet werden muß. Ein dynamisches Percolationsmodell für Scherprozesse wird entwickelt, welches ein Potenzgesetz für das Kurzzeitverhalten der Kriechnachgiebigkeit ergibt. Der relevante Exponent liegt zwischen 0,3 und 0,47 und ist definitiv kleiner als 1/2. Der experimentelle Wert für den Andradeexponenten ist ungefhr 1/3.
    physica status solidi (b) 02/2006; 124(2):515 - 524. · 1.49 Impact Factor
  • E Donth
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    ABSTRACT: A chain of ideas is described connecting the theory of quantum-mechanical experiments with practical research in the relaxation of liquids, biological materials, and materials science. The chain culminates at the proposal of an experimentum crucis comparing dynamic neutron scattering, dynamic calorimetry, and computer simulation of the same substances at the crossover region of the dynamic glass transition. The conclusiveness of the experimentum crucis backwards the chain is discussed. The role of relaxation of liquids in confining geometries is also discussed, especially with respect to the confirmation of the von Laue variant for the characteristic length of glass transition as alternative to their Gibbs treatment that results in too large lengths.
    The European Physical Journal E 10/2003; 12(1):11-8. · 2.18 Impact Factor
  • A. Schönhals, E. Donth
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    ABSTRACT: Die physikalische Alterung von amorphen Polymeren wird ausgehend von experimentellen Ergebnissen auf phänomenologischem Niveau diskutiert, wobei die physikalische Alterung als selbständiger Relaxationsprozeß verstanden wird. Unter Benutzung einer allgemeinen Scalinghypothese wird ein konsistentes Bild für die physikalische Alterung entwickelt, in dem die beobachteten Effekte diskutiert werden. Die entsprechende Mikrodynamik besitzt demnach kooperativen Charakter, deren räumliche Grenzen durch die sekundären Relaxationen (Korrelationslänge ≈ 0,4 nm) und durch den Glasübergang (Korrelationslänge ≈ 2 nm bei T = Tg) gegeben sind.The physical aging in amorphous polymers is phenomenologically discussed on the basis of selected experimental facts. Physical aging is considered as an independent relaxation process. Using a general scaling hypothesis, a consistent picture of physical aging is presented, in which the experimental facts are discussed. The corresponding mode lengths vary between 0.4 nm (characteristic for local modes) and about 2.0 nm (characteristic for the proper glass transition).
    Acta Polymerica 04/2003; 37(8):475 - 480.
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    ABSTRACT: DSC measurements around the glass transition in the homologous series of seven poly(n-alkylmethacrylate)s (alkyl=methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl) are presented. The step height Δcp decreases linearly with the number of n-alkyl C-atoms in the side chain. The usual glass step in the DSC curves, e. g. for poly(methylmethacrylate), degenerates to a bend near poly(n-octylmethacrylate). This finding is discussed as a result of a linear relation between the caloric relaxation strength Δcp and the temperature difference from the onset Tonset in the splitting region of poly(n-alkylmethacrylate)s, with Δcp → 0 for T → Tonset. The number of monomeric units per cooperatively rearranging region at Tg decreases from PMMA (N∼20) to PnOMA (N<5). This demonstrates that the cooperativity at the onset in poly(n-alkylmethacrylate)s is very small, as expected from a fluctuation approach to the glass transition.
    Acta Polymerica 04/2003; 47(11‐12):525 - 529.
  • K. Schneider, E. Donth
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    ABSTRACT: Ein einheitliches Konzept für die Beschreibung unterschiedlicher Relaxationsmessungen des Hauptrelaxationsbietes (Glasübergang) wird skizziert. Experimentelle Werte von Schermessungen, dielektrischen Messungen, Kernresonanz-relaxationsmessungen und dynamischen kalorimetrischen Messungen (DSC) werden entsprechend modelliert. Die gegenseitige Lage der charakteristischen Frequenzen, die bei dieser Beschreibung erhalten werden, wird für zwei amorphe Polymere (PVAC, PS) dargestellt.A general concept for the description of different relaxation measurements of the main transition (dynamic glass transition) is sketched. New experimental data of shear, dielectric and NMR relaxation, and of dynamic calorimetric (DSC) measurements are modelled according to this concept. The mutual arrangement of the characteristic frequencies obtained are represented for two amorphous polymers (poly(vinyl acetate) and polystyrene).
    Acta Polymerica 04/2003; 37(6):333 - 335.
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    ABSTRACT: Hindering and final blocking of the normal melt crystallization in central ethylene oxide (EO) blocks by methyl methacrylate (MMA) end blocks of increasing lengths in ABA type triblock copolymers synthesized anionically in a new way are investigated by differential scanning calorimetry and X-ray scattering. Experimental studies of glass transitions, low temperature nucleation, and the morphologic ten-nanometer structure are included. Low percentage amounts of long homo-PEO chains can crystallize in an ABA matrix which otherwise is not normally crystallizable. It is concluded from the experiments that in our systems with PEO molecular masses up to 50 000 g/mol the motion of the chain ends is necessary for melt crystallization under normal conditions.Die Behinderung und letztliche Blockierung der normalen Schmelzkristallisation von zentralen Ethylenoxid[EO]-Blöcken durch Methylmethacrylat-(MMA)-Endblöcke ansteigender Läange in Triblockcopolymeren vom Typ ABA, anionisch auf einem neuen Weg synthetisiert, wurden mit Hilfe der differentiellen Scanning-Calorimetrie und der Röntgenstreuung untersucht. Experimentelle Untersuchungen des Glasiihergangs, der Keimbildung bei tiefen Temperaturen und der morphologischen Zehn-Nanometer-Struktur werden eingeschlossen. Geringe Mengen (Prozentbereich) langer Homo-PEO-Ketten können in einer ABA-Matrix kristallisieren, welche sonst normal nicht kristallisierbar ist. Aus den Experimenten wird geschlossen, daß in den untersuchten Systemen mit PEO-Molekiilmassen bis zu 50 000 g/mol eine Bewegung der Kettenenden notwendig ist fur die Schmelzkristallisation unter normalen Bedingungen.
    Acta Polymerica 03/2003; 38(5):260 - 270.
  • E. Donth, K. Schneider
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    ABSTRACT: A survey of transition phenomenology in amorphous entangled polymers is presented. Using a general scaling hypothesis characteristic lengths are systematically attached to the different zones of the multiple glass transition. New experimental results show the location of caloric spectra between the peaks of G″ and J″ on the common frequency scale. A fine structure of the main transition is suggested. There are two components: (i) The proper glass transition zone with mode lengths up to 2 nm. This length scale is determined from the caloric spectra. (ii) The hindering zone of cooperative motion of polymer chain segments between entanglement points with mode lengths up to 10 nm.Ein Überblick der Relaxationsphänomenologie in amorphen verschlauften Polymeren wird gegeben. Unter Benutzung einer allgemeinen Skalenhypothese werden den verschiedenen Zonen des multiplen Glasübergangs systematisch charakteristische Längen zugeordnet. Neue experimentelle Ergebnisse zeigen, daß auf einer gemeinsamen Frequenzskale die kalorischen Spektren zwischen den Maxima von G″ und J″ liegen. Eine Feinstruktur des Hauptübergangs wird vorgeschlagen. Es gibt zwei Komponenten: 1. Die eigentliche Glasübergangszone mit Modenlängen bis zu 2 nm. Diese Länge wird aus kalorischen Spektren erhalten. 2. Eine Behinderungszone der kooperativen Bewegung von Polymerkettensegmenten zwischen den Verschlaufungen mit Modenlänge bis zu 10 nm.
    Acta Polymerica 03/2003; 36(5):273 - 278.
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    ABSTRACT: The size of glass transition cooperativity for 11 polymers and glycerol is determined from heat capacity spectroscopy (HCS) and differential scanning calorimetry (DSC) by using a calorimetric fluctuation formula. The data cover in total the 0.25 ≤ x ≤ 0.95 part of the reduced temperature interval between the Vogel temperature and a cooperativity onset temperature. A steep cooperativity increase at lower temperature is observed. The data are consistent with the hypothesis that the temperature dependence can be described by the enlargement of a minimal cooperativity at the onset.
    Acta Polymerica 03/2003; 48(9):369 - 378.
  • E. Donth, K. Schneider
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    ABSTRACT: The phenomenological interpretation of shear curves is refined by application of the fluctuation dissipation theorem and the WIENER-KHINTCHIN theorem. The loss peaks of shear modulus and compliance near the glass transition of amorphous polymers can be attributed to two different molecular motions. An interpretation of the two peaks by one kind of molecular motion (uniform model) would imply that its flanks two logarithmic frequency decads away from the center were significantly more intensive than other molecular motions at these frequencies.Die phänomenologische Interpretation der Scherkurven wird verfeinert durch die Anwendung des Fluktuation-Dissipation-Theorems und des WIENER-CHINČIN-Theorems. Die Verlustmaxima des Schermoduls und der Schernachgiebigkeit am Glasübergang amorpher Polymere können zwei verschiedenen molekularen Bewegungen zugeordnet werden. Eine Interpretation der zwei Maxima durch eine Art molekularer Bewegungen (uniformes Modell) würde implizieren, daß ihre Flanken in einer Entfernung von zwei logarithmischen Dekaden vom Zentrum signifikant intensiver wären als andere molekulare Bewegungen bei diesen Frequenzen.
    Acta Polymerica 03/2003; 36(4):213 - 215.
  • E. Donth
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    ABSTRACT: The dynamic approach to the glass transition is described on the basis of the von Laue approach to thermodynamic fluctuations leading to a Levy situation for the corresponding subsystems. The configurational approach is described on the basis of the Mezard Parisi scenario using the Gibbs distribution for the calculation of an ideal glass transition at the Kauzmann temperature. Two kinds of calorimetric experiments are described which are consistent with the von Laue approach to subsystem fluctuations and which are inconsistent with the Gibbs approach to subensemble fluctuations. A specific dynamic approach is described that is not consistent with the configurational ideal glass transition. Several examples of dynamic glass transition phenomena, for different processes in the Arrhenius diagram, can qualitatively be explained by the extraordinary concentration of free volume in relatively small spatial spots caused by the preponderant Levy component for spectral densities of fluctuations for extensive thermodynamic variables.
    Journal of Non-Crystalline Solids 09/2002; · 1.72 Impact Factor
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    E. Donth, E. Hempel
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    ABSTRACT: Structural relaxation is understood as the relaxation from a non-equilibrium glass state towards the equilibrium, and not from only the non-ergodic glass zone of the equilibrium liquid to the ergodic liquid or flow zone of the equilibrium liquid (response across the dynamic glass transition). Structural relaxation is, therefore, usually connected with temperatures below the glass temperature Tg. For short pulses or large heating or cooling rates Ṫ we get, however, structural relaxation also in a certain temperature range above Tg. Non-linearity for structural relaxation and equilibrium response are compared. Single and double pulse responses above the glass temperature are analyzed by simulation with the Narayanaswamy Moynihan model. The model substance parameters are chosen to be similar to those of polyvinylacetate. For steep pulse flanks of |Ṫ|=480 K/min (as, e.g., for optical experiments), we obtain surprisingly long exchange times, e.g., up to 7 s at a temperature 10 K above Tg, where the τKWW equilibrium time of the α process is only 0.52 s.
    Journal of Non-Crystalline Solids 01/2002; 306(1):76-89. · 1.72 Impact Factor
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    K Schröter, E Donth
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    ABSTRACT: The dynamic shear response of six glass formers (the epoxy resin diglycidyl ether of bisphenol-A, propylene carbonate, glycerol, two bulk metallic glasses, and a soda lime glass) from different substance classes with widely differing fragility is compared: No correlation of the shear Kohlrausch exponent with fragility was observed. A comparison of shear with multidimensional NMR results on glycerol is compatible with dynamic heterogeneity in glass formers having mobile islands in a lesser mobile matrix.
    Journal of Non-Crystalline Solids 01/2002; · 1.72 Impact Factor
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    ABSTRACT: Dielectric and mechanical relaxation processes in the series of poly(n-alkyl methacrylates) (PnAMA) depend systematically on the number of carbons in the alkyl part of the side chain. The crossover region of the dynamic glass transition shifts to lower frequencies for increasing this C number and reaches, above the hexyl member (C = 6), frequencies accessible to the temperature modulated DSC (TMDSC). The whole series from C = 1 (poly(methyl methacrylate), PMMA) to C = 11, the undecyl member is investigated by TMDSC and enthalpy retardation with DSC. The calorimetric result in the series are compared with the dielectric and mechanical data and are discussed with respect to the crossover region and a polyethylene-like glass transition (alpha(PE) process) due to a nanophase separation in these homopolymers. (C) 2002 Elsevier Science B.V. All rights reserved.
    Thermochimica Acta 01/2002; 391(1-2):219-225. · 1.99 Impact Factor
  • E. Donth, C. Austen Angell
    Physics Today 01/2002; 55(12):60-61. · 6.76 Impact Factor

Publication Stats

926 Citations
153.19 Total Impact Points

Institutions

  • 1994–2007
    • Universitätsklinikum Halle (Saale)
      Halle-on-the-Saale, Saxony-Anhalt, Germany
  • 1992–2006
    • Hochschule Merseburg
      Merseburg, Saxony-Anhalt, Germany
  • 1993–2003
    • Martin Luther University of Halle-Wittenberg
      Halle-on-the-Saale, Saxony-Anhalt, Germany
  • 2001
    • University of Rostock
      • Institut für Physik
      Rostock, Mecklenburg-Vorpommern, Germany