Amorphous state definition

Given the above definition of a bond distance, we can analyze species lifetimes. The lifetime of all species is less than 12 fs above 2.6g/cc, which is roughly the period of an O-H bond vibration (ca. 10 fs). Hence, water does not contain any molecular states above 75 GPa and at 2000 K but instead forms a collection of short-lived transient states. The L simulations at 2.6g/cc (77 GPa) and 2000 K yield lifetimes nearly identical to that found in the S simulations (within 0.5 fs), which indicates that the amorphous states formed from the L simulations are closely related to the superionic bcc crystal states found in the S simulations. 

Another factor that has been claimed to influence the electrocatalytic properties of materials is the degree of crystallinity [52]. In particular, metals and metal alloys in an amorphous state have attracted interest as electrocatalysts for H2 evolution. In practice, amorphization is promoted by adding a non-metal such as B or P. However, evident effects are minor and there is no definitive proof that such an approach is worth practical consideration. Moreover, recrystallization of materials may take place under operating conditions [27]. 

We believe that the conclusion reached is of general significance for all polymers in the amorphous state. However, Eq. (74) cannot readily be applied to noncrystal-lizable polymers, because in this case the value of v"3 or of a becomes obscure. In attempting to extend the main ideas put forward above to cover this case, we employ an alternative definition of/g, that is... 

To a first approximation, volumes change linearly with temperature (see Figure 10-1). Consequently, with the definition of the cubic expansion coefficient a, the following is obtained for the liquid state and the amorphous state ... 

By definition, no long-range order over extensive regions occurs in the amorphous state For example, amorphous material is not X-ray crystalline. This definition, of course, does not consider the mutual arrangement in space of short chain segments or the order of the molecule itself. 

This chapter is a brief introduction to the general concepts and definitions of the amorphous state. Techniques for the characterization of amorphous materials and their transformations are reviewed. Also, structural and chemical changes which can lead to inhomogeneities, and the detection of these inhomogeneities, are discussed. Because of the difficulty in completely characterizing amorphous materials, one must be aware of the possible structures, transformations, and inhomogeneities which can occur in order to better interpret measured properties. 

A noncrystalline polymeric material that has no definite order or crystallinity. A polymer in which the macromo-lecular chain has a random conformation in solid (glassy or rubbery) state. On the one hand, an amorphous polymer may show a short range order, while on the other, a crystalline polymer may be quenched to the amorphous state (viz., polyethylene terephthalate (PET)). The maximum value of a periodically varying function, e.g., used to describe the energy transmitted from the ultrasonic welding horn to the weld joint. 

Polymer mechanical properties are one from the most important ones, since even for polymers of different special-purpose function a definite level of these properties always requires [20]. Besides, in Ref [48] it has been shown, that in epoxy polymers curing process formation of chemical network with its nodes different density results to final polymer molecular characteristics change, namely, characteristic ratio C, which is a polymer chain statistical flexibility indicator [23]. If such effect actually exists, then it should be reflected in the value of cross-linked epoxy polymers deformation-strength characteristics. Therefore, the authors of Ref [49] offered limiting properties (properties at fracture) prediction techniques, based on a methods of fractal analysis and cluster model of polymers amorphous state structure in reference to series of sulfur-containing epoxy polymers [50]. 

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