Mechanische Messung chemischer Bindefestigkeiten

Smekal, Adolf; Klemm, W.

doi:10.1007/bf00900835

Cited by 13 publications

(6 citation statements)

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“…While the intra-SRO forces are typically pure binding e.g. covalent or ionic type, those connecting SROs are usually mixed binding forces, subjected to deformation and polarization and thereby resulting in VW forces [38,40]. The presence of network modifiers e.g.…”

Section: Hierarchy Of Order and Local Interactionsmentioning

confidence: 99%

“…The U is the sum over inter-molecular interactions of SRO molecules lying within MRO length scales. The inter-SRO interactions being relatively weaker as compared to intra-SRO ones [5,39,40] (subjected only to mixed bonding [38,40,41,43,44], U can be described as a sum over coulomb and repulsive potential energies and a perturbation series of polarization corrections only [51,55]:…”

Section: Intermolecular Interactions Among Sro Structuresmentioning

confidence: 99%

“…The bonding interactions at short range (up to 1st and 2nd nearest neighbor molecular distances), are dictated by the valance force fields (e.g. covalent or ionic, also acting as mechanical con-straints) but the medium range order (MRO) (typically of the order of 10-30 Å, is governed by the VW interactions [38][39][40][41][42][43][44]. Intuitively these varying structures at different length scales are expected to result in materials with very different physical properties.…”

Section: Introductionmentioning

confidence: 99%

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Low temperature heat capacity of nanosize amorphous solids

Shukla

2021

J. Phys.: Condens. Matter

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Contrary to previous studies based on bulk materials, we analyze the behavior of the vibrational density of states (VDOS) and specific heat of an amorphous solid of nano-scales (∼3 nm) at low temperature. With Hamiltonian formulation based on the intermolecular dispersion forces, our analysis indicates a universal semi-circle form of the average VDOS in the bulk of the spectrum along with a super-exponentially increasing behavior in its edge. The latter in turn leads to a specific heat with a superlinear temperature (T) dependence below T < 1 K even at nano-scales, and, surprisingly agreeing with the experiments although the latter are carried out at macroscopic scales. The omnipresence of dispersion forces at microscopic scales indicates the application of our results to other disordered materials too.

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Section: Hierarchy Of Order and Local Interactionsmentioning

confidence: 99%

Section: Intermolecular Interactions Among Sro Structuresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Low temperature heat capacity of nanosize amorphous solids

Shukla

2021

J. Phys.: Condens. Matter

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“…Many criteria (dealing with structural and thermo-kinetic orders) were proposed to explain the oxides glass-forming ability (GFA). They are founded on crystallochemical concepts or refer to the criteria linked to the nature, the chemical bond strength and other characteristics of metal oxides (Goldschmidt 1926;Zachariasen 1932;Dietzel 1941;Stanworth 1946Stanworth , 1948Stanworth , 1952Sun 1947;Smekal 1951;Rawson 1956Rawson , 1967Turnbull 1969;Hrubý and Štourač 1974;Minaev 1978Minaev , 1980Minaev , 1983Minaev , 1991Štěpánek and Hrubý 1980;Cervinka and Hrubý 1982;Inoue et al 1990;Lu et al 2000;Stoch 2001;Lu and Liu 2003;Rao et al 2004). The main purpose is to predict and/or describe how any single oxide (and under what conditions) is able to form glasses.…”

Section: Introductionmentioning

confidence: 99%

“…Inspired by the atomic field of Dietzel (1941), Stanworth (1946Stanworth ( , 1948Stanworth ( , 1952 and Smekal (1951) added details of electronegativity and bonding nature between E atoms and oxygen atoms in E x O y oxide. Thermodynamical theory of glass formation was proposed as the 'energy criterion' by Sun (1947) who attempted to establish a correlation between the bond strengths (between the cation E y+ and the anion O 2− ) and this aptitude.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic and relative approach to compute glass-forming ability of oxides

2013

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This study deals with the evaluation of glass-forming ability (GFA) of oxides and is a critical reading of Sun and Rawson thermodynamic approach to quantify this aptitude. Both approaches are adequate but ambiguous regarding the behaviour of some oxides (tendency to amorphization or crystallization). Indeed, ZrO 2 and Al 2 O 3 were inappropriately listed by Sun and Rawson to be glassformer oxides while being intermediate ones. We present a non-dimensional approach to value GFA of single oxide by affecting to each one of the coefficients (without measuring units). Obeying to the non-dimensional analysis rules, we introduce a neglected (in all prior thermodynamic models) characteristic: the isobaric heat capacity (C p) of oxides, and execute a mathematical treatment of oxides thermodynamic data. We note this coefficient as thermodynamical relative glass-forming ability (ThRGFA) and formulate a model to compute it. Computed values of 2nd, 3rd, 4th and 5th period metal oxides reveal a clear differentiation between them. Indeed, all glass former oxides are characterized by ThRGFA values over 1•709. Moreover, the value intervals confirm the oxides classification into three groups (forming, intermediate and modifier) and sorting of the former ones in distinctive strong and fragile oxides.

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Kinetik der Hartzerkleinerung

Patat

Langemann

1959

Chemie Ingenieur Technik

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Die bisherigen formalen Theorien der Hartzerkleinerung vermogen die experimentellen Ergebnisse n u r in beschranktem Umfange zu deuten. Sie besitzen weder physikalischen lnhalt noch berucksichtigen sie die Stoffeigenschaften der Mahlguter. Urn die Zusamrnenhange zwischen Zerkleinerungsgeschwindigkeit und Mahlguteigenschaften zu erfassen, wird eine Methode der differentiellen Zerkleinerung vorgeschlagen und modellmaflig in Kugelmuhlen mit Kristallquarzfraktionen erprabt. Die Ergebnisse gestatten quantitative Aussagen uber das Festigkeits-und das Lockerstellenspektrum desMahlgutes sowie uber seineTemperaturabhangigkeit bei der Zerkleinerung Einleitung und Problemstellung

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Mechanische Messung chemischer Bindefestigkeiten

Cited by 13 publications

References 0 publications

Low temperature heat capacity of nanosize amorphous solids

Low temperature heat capacity of nanosize amorphous solids

Thermodynamic and relative approach to compute glass-forming ability of oxides

Kinetik der Hartzerkleinerung

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