Regularity bands

We might also mention that, for this rule, the region of color-indeterminacy, somewhat arbitrarily defined as the set of sites having. 4 < W <. 6, takes on a sirail2urly regular band-pattern. 

Crystallinity In crystallization of polymers, the polymer forms crystalline and amorphous regions [2,4,25]. The formation of crystalline regions is accompanied by an increase in new vibrational modes caused by their crystal lattice interactions [2]. The IR spectrum of a given polymer differs by various absorption bands, depending on whether it is in the amorphous or crystalline state [2]. The IR spectrum exhibits regularity bands, splitting, and frequency shifts. Other absorption bands are not affected by crystallization and remain the same in both cases. Crystalline and amorphous bands can be used in the determination of the degree of crystallinity independent bands are useful for the determination of sample thickness [2],... 

A simple super or s-virtual bond scheme is developed for the treatment of tertiary or superhelical structure in polynucleotide chains. The scheme Is utilized to examine the enormous variety of tertiary structure that can be generated by regularly banding a B-DNA reference helix at the phosphodiester linkages. 

AGATE. Agate is a variety of chalcedony, whose variegated colors are distributed in regular bands or zones, in clouds or in dendritic forms, as in moss agate. 

Using a laser operating on 14C1602, the regular band of which spans 12.0 pm, it is possible to perform the experiment with a transverse geometry with a fast ion beam, or with a slower ion beam, for example from an ECR ion source. A possible setup is outlined in fig. 6. Because of the shorter interaction time, a build-up... 

It is noteworthy that the width of an absorption signal is inversely proportional to the lifetime of the excited state (Heisenberg s uncertainty principle). Hence, for gases, the lifetime is long and the absorption lines are sharp. This is why small di- or triatomic molecules sampled in the gas state and at low pressures can lead to spectra containing narrow regular bands whose positions enable the elucidation of the various energetic states predicted by the theory. 

The determination of polyethylene crystallinity includes all polyethylene present in the copolymer, whereas measurements on the regularity bands of C3 give only the number of units either isotactically or syndiotactically arranged. Amorphous polypropylene, on the other hand, cannot be distinguished from the C3 portion of the copolymer by IR spectroscopy alone and is included in the total C3 percentage11. 

More regular band spacing along the chromatogram... 

In recent years, excited chemical bonds have been studied experimentally by IR and Raman spectroscopy. To observe the excited chemical bonds, Vettegren [30,32,33, 39], Vettegren et al. [24-29,31, 34-38], and others [56-58] analyzed the shape of the regularity bands in spectra of different polymers. These bands correspond to the vibrauons of sequence of chemical bonds in the macromolecule, forming a helix or a planar zigzag. Deformation of valence angles and bonds causes a frequency shift, Av. The latter is related to the deformation of a hehx by the equation [39] ... 

Indeed, systematic and careful spectroscopic investigations [30, 32, 33, 39] showed that there do exist weak satellites both on the low-frequency wing and (with lower intensity) on the high-frequency wing of the regularity band. They are displayed in Fig. 6. The peaks of the satellites are shifted from the main peak by some tens of cm (see Table 2 and they are ca. 1 — 10% as intense as the main band. 

Table 2. Some characteristics of the regularity bands and deformation of the excited chemical bonds in macTomolecules of non-stressed polymers at 300 K...

Fig. 7. Regularity band with satellites in the Raman spectrum of PP at 300 K (1) in the Stokes...

Figure 7 demonstrates the regularity band of PP in the Raman spectrum and the relative phonon occupation number for the extended excited bonds, Nj/No, and that for the compressed excited bonds, Nq/Nq, where No is the equilibrium occupation number. It is clear that Nj/No > 1 and Np/No < 1. N is related with temperature by the expression [61] ... 

In Figs. 21 and 22, the regularity-band frequencies, v, and the F(0/T) function are plotted as function of temperature. 

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