Polarizing microscopy characteristics

Figure 3. Polymer/monomer state diagram of p-methyl, p -acryloyloxyazoxybenzene obtained by polarizing microscopy Mp composition (weight fraction of polymer). Characteristic points ( ), decreasing birefringence CY), mesomorphic transition mesomorphic melting (%), solidus (O), liquidus. The meaning of the areas (A), isotropic liquid (B), isotropic liquid -j- mesomorphic plasticized polymer (C), liquid (D), glassy states of plasticized polymer in mesomorphic phase (E), crystalline monomer -f mesomorphic plasticized polymer in the glassy state (F), crystalline monomer -j-mesomorphic plasticized polymer in the liquid state (G), mesomorphic monomer -f mesomorphic plasticized polymer in the liquid state.

Scanning electron microscopy (SEM) has been used to characterize the physical and chemical interaction of fibres in FRC, as well as to address the durability of fibres. Microstructural analysis provides information on the corrosion of fibres, deposits of Portlandite surrounding fibres and the interaction between fibres and matrix (Purnell et al., 2000). Other techniques may be used as alternative to SEM. Uygunoglu (2008) has shown that polarizing microscopy is a suitable technique to assess the bond characteristics of steel fibres in SFRC, which is also related to durability of the composite. 

Figures. The phase diagram of the DSCG/water system (as determined by hot stage polarizing microscopy). The double peritectic form of this diagram has come to be regarded as the classic chromonic pattern. Note, in particular, the characteristic sequence of phases formed by samples within the composition range indicated by the shaded band.

The diffusion, location and interactions of guests in zeolite frameworks has been studied by in-situ Raman spectroscopy and Raman microscopy. For example, the location and orientation of crown ethers used as templates in the synthesis of faujasite polymorphs has been studied in the framework they helped to form [4.297]. Polarized Raman spectra of p-nitroaniline molecules adsorbed in the channels of AIPO4-5 molecular sieves revealed their physical state and orientation - molecules within the channels formed either a phase of head-to-tail chains similar to that in the solid crystalline substance, with a characteristic 0J3 band at 1282 cm , or a second phase, which is characterized by a similarly strong band around 1295 cm . This second phase consisted of weakly interacting molecules in a pseudo-quinonoid state similar to that of molten p-nitroaniline [4.298]. 

Phospholipids, which are one of the main structural components of the membrane, are present primarily as bilayers, as shown by molecular spectroscopy, electron microscopy and membrane transport studies (see Section 6.4.4). Phospholipid mobility in the membrane is limited. Rotational and vibrational motion is very rapid (the amplitude of the vibration of the alkyl chains increases with increasing distance from the polar head). Lateral diffusion is also fast (in the direction parallel to the membrane surface). In contrast, transport of the phospholipid from one side of the membrane to the other (flip-flop) is very slow. These properties are typical for the liquid-crystal type of membranes, characterized chiefly by ordering along a single coordinate. When decreasing the temperature (passing the transition or Kraft point, characteristic for various phospholipids), the liquid-crystalline bilayer is converted into the crystalline (gel) structure, where movement in the plane is impossible. 

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