Amorphous atomic number, dependence

The interaction of cellulose with various liquids is accompanied by exothermic heat effects (loelovich, 2011). The interaction enthalpy of cellulose with low-polar liquids, e.g., alcohols having numbers of C-atoms S2, is not function of amorphicity degree, and depends on specific surface of the pores. Some other liquids. 

Hydrogenated amorphous silicon is not a homogeneous material. Its structure is thought to consist of voids embedded in an amorphous matrix [62, 63]. The size and number density of the voids depend on the deposition conditions. Poor-quality material can have a void fraction around 20%, while device quality a-Si H has been shown to contain fewer voids, 1%. with a diameter of 10 A [64-66]. The surfaces of the voids may be partly covered with hydrogen atoms [62, 67],... 

Table 8.53 shows the main features of XAS. The advantages of EXAFS over diffraction methods are that the technique does not depend on long-range order, hence it can always be used to study local environments in amorphous (and crystalline) solids and liquids it is atom specific and can be sensitive to low concentrations of the target atom (about 100 ppm). XAS provides information on interatomic distances, coordination numbers, atom types and structural disorder and oxidation state by inference. Accuracy is 1-2% for interatomic distances, and 10-25 % for coordination numbers. 

The reliability of molecular mechanics calculations hinges entirely on the validity and range of applicability of the force field. The parameterisation of these functions (the force field) represents the chemistry of the species involved. Many force fields have been developed and the one used in any application usually depends on the molecular mechanics package being used. The force field itself can be validated against experimental and ab initio results. Because of the relative speed of molecular mechanics calculations, it is possible to consider routine calculations of a large number of atoms, certainly tens of thousands, which makes the method amenable to calculations on polymers. To remove surface effects, calculations of bulk properties are normally carried out employing 3D periodic boundaries. In this way it is possible to perform calculations on both amorphous and crystalline systems. 

Irrespectively of the iron content, the applied synthesis procedure yielded highly crystalline microporous products i.e. the Fe-ZSM-22 zeolite. No contamination with other microporous phases or unreacted amorphous material was detected. The SEM analysis revealed that size and morphology of the crystals depended on the Si/Fe ratio. The ZSM-22 samples poor in Fe (Si/Fe=150) consisted of rice-like isolated crystals up to 5 p. On the other hand the preparation with a high iron content (Fe=27, 36) consisted of agglomerates of very small (<0.5 p) poorly defined crystals. The incorporation of Fe3+ into the framework positions was confirmed by XRD - an increase of the unit cell parameters with the increase in the number of the Fe atoms introduced into the framework was observed, and by IR - the Si-OH-Fe band at 3620 cm 1 appeared in the spectra of activated Fe-TON samples. 

X-ray diffraction experiments are applicable to all crystalline and amorphous solids and to all liquids and dispersions. The intensity of the X-ray scattering depends on the number of electrons in the atoms. Consequently, the obtainable information is limited in materials containing only light atoms. No information is obtained about the locations of hydrogen atoms. 

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