Structural Models of Selenite Glasses Containing Ag+ and Cu2+ Ions

2008 ◽  
Vol 39-40 ◽  
pp. 45-48 ◽  
Author(s):  
Albena Bachvarova-Nedelcheva ◽  
Reni Iordanova ◽  
Yanko B. Dimitriev
Keyword(s):  
Glass Formation ◽  
Amorphous Materials ◽  
Structural Models ◽  
Point Of View ◽  
Glass Formation Ability ◽  
New Class

Selenite glasses are a new class of amorphous materials which are interesting mainly from a scientific point of view and they are not yet fully examined. Selenite glasses containing other non-traditional glass formers (TeO2, V2O5 and MoO3) as well as network modifiers (Ag+, Cu2+, Zn2+, etc.) were obtained. The aim of the present study is to explain the glass formation ability in selenite systems with the participation of modifiers (Ag+ and Cu2+) and MoO3.

Diffraction techniques and structural models for amorphous materials

1992 ◽  
Vol 150 (1-3) ◽  
pp. 65-68 ◽  
Author(s):  
G. Ennas ◽  
M.P. Medda ◽  
A. Musinu ◽  
G. Piccaluga ◽  
G. Pinna
Keyword(s):  
Amorphous Materials ◽  
Structural Models

scholarly journals General Decay Rate of Solution for Love-Equation with Past History and Absorption

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1632
Author(s):  
Khaled Zennir ◽  
Mohamad Biomy
Keyword(s):  
Decay Rate ◽  
Source Term ◽  
Blow Up ◽  
Past History ◽  
Point Of View ◽  
General Decay ◽  
General Decay Rate ◽  
Infinite Memory ◽  
New Class ◽  
The Relationship

In the present paper, we consider an important problem from the point of view of application in sciences and engineering, namely, a new class of nonlinear Love-equation with infinite memory in the presence of source term that takes general nonlinearity form. New minimal conditions on the relaxation function and the relationship between the weights of source term are used to show a very general decay rate for solution by certain properties of convex functions combined with some estimates. Investigations on the propagation of surface waves of Love-type have been made by many authors in different models and many attempts to solve Love’s equation have been performed, in view of its wide applicability. To our knowledge, there are no decay results for damped equations of Love waves or Love type waves. However, the existence of solution or blow up results, with different boundary conditions, have been extensively studied by many authors. Our interest in this paper arose in the first place in consequence of a query for a new decay rate, which is related to those for infinite memory ϖ in the third section. We found that the system energy decreased according to a very general rate that includes all previous results.

Glass Formation Ability and Kinetics of the Gd 55 Al 20 Ni 25 Bulk Metallic Glass

2006 ◽  
Vol 23 (3) ◽  
pp. 672-674 ◽  
Author(s):  
Jo Chol-Lyong ◽  
Xia Lei ◽  
Ding Ding ◽  
Dong Yuan-Da
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Glass Formation ◽  
Glass Formation Ability ◽  
Kinetics Of

[Fe2(SR)2(μ-CO)(CNMe)6]2+and Analogues:  A New Class of Diiron Dithiolates as Structural Models for the HoxAirState of the Fe-Only Hydrogenase

2004 ◽  
Vol 126 (46) ◽  
pp. 15151-15160 ◽  
Author(s):  
Christine A. Boyke ◽  
Thomas B. Rauchfuss ◽  
Scott R. Wilson ◽  
Marie-Madeleine Rohmer ◽  
Marc Bénard
Keyword(s):  
Structural Models ◽  
New Class

scholarly journals Interrogative modifications of mononuclear and two-member sentences in modern Russian

2021 ◽  
Vol 1 (24) ◽  
pp. 67-73
Author(s):  
Alya V. Kanafieva ◽  
Keyword(s):  
Structural Models ◽  
Point Of View ◽  
Semantic Features ◽  
Interrogative Sentence ◽  
Modern Russian

The purpose of the article is to define and characterize the paradigm of interrogative modifications of mononuclear and two-member sentences that have the function of an expressive message, which do not imply a verbally expressed answer. The article substantiates the convenience of their definition as rhetorical statements. Members of each paradigm are analyzed from the point of view of their structure and semantic features, considering not only the standard meanings of denial, affirmation and subjective reflection, but also modal and emotional-evaluative shades. The article points out the peculiarities of their intonation which is different from the intonation of an interrogative sentence; the specifics of the structure (the presence of reinterpreted interrogative-pronominal words (pronominal components) and interrogative particles, that represent rhetorical formants); a complex of subjective-modal meanings. These properties create the expressiveness of the analyzed models. We also draw attention to their phraseological character, though the degree of their impenetrability is not as high as that of the actual phraseological units. Taking into consideration the above aspects, we analyze the paradigm of interrogative modifications of some mononuclear and two-member sentences with a supporting component что, also included in the analytical predicative combinations что толку, что пользы, что нужды, etc. We note the specifics of modal-temporal meanings of interrogative modifications in comparison with typical structural models of mononuclear and two-member sentences, as well as a tendency towards generalization of these meanings. Standard predicate-modal meanings of inexpediency and unimportance are enriched with various emotional shades of subjective modality. Among the analyzed models, the article highlights evaluative ones with a predicate что (что такое) in two-member models and with analytical predicate forms: что хорошего (плохого, удивительного, странного, etc.).

Echinodermata

1989 ◽  
Author(s):  
Heinz A. Lowenstam ◽  
Stephen Weiner
Keyword(s):  
Amorphous Materials ◽  
Sea Urchins ◽  
Polarized Light ◽  
Magnesium Carbonate ◽  
Point Of View ◽  
Sea Stars ◽  
Mineralized Tissues ◽  
The Individual ◽  
Almost All ◽  
And Function

The Echinodermata are certainly one of the most unusual and interesting phyla from the biomineralization point of view. They all live in the marine environment. The five major taxonomic classes (Asteroidea or sea stars, Ophiuroidea or brittle stars, Echinoidea or sea urchins, Crinoidea or sea lilies, and Holothuroidea or sea cucumbers) have quite different anatomical shapes and are characterized by fivefold symmetry. Each group forms mineralized hard parts. In the Echinoidea the skeletal elements are fused together to form a rigid test, whereas in the Asteroidea, Ophiuroidea and Crinoidea the skeletal elements or ossicles are articulated with one another. In the Holothuroidea the skeleton is usually reduced to microscopic ossicles or spicules, and, in some cases, mineralized granules as well. The hard parts of echinoderms vary enormously in shape and function and include not only the diverse skeletal elements, but also spines and teeth. Remarkably, with very few exceptions, the mineralized hard parts are formed from the same mineral, magnesium-bearing calcite [usually 5–15% as magnesium carbonate (Chave 1952, 1954; Raup 1966)], which has some unique and interesting properties. The ultrastructure of many of the macroscopic skeletal hard parts has a characteristic spongy or fenestrate structure (called the stereom) and is riddled with labyrinthine cavities (collectively called the stereom space). In echinoid spines the stereom spaces are secondarily filled in to form areas of solid mineral. The surfaces of the mineral phase are very smooth, even when examined a high magnification in the SEM (Towe 1967; Millonig 1970). Furthermore, the broken surfaces show no characteristic ultrastructural motif, which is observed in almost all other mineralized tissues in which the individual crystals are enveloped by layers of organic material. The fracture surfaces of echinoderm calcite actually have a conchoidal cleavage (Towe 1967), which is characteristic of glassy or amorphous materials. It is, therefore, most surprising that when individual skeletal plates, spines, spicules, ossicles, and even whole teeth are examined in polarized light or by X-ray diffraction, they behave as if they are single crystals! (Towe 1967; Donnay and Pawon 1969).

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