Maltese cross textures

Maltese cross, textures 410 mapping, thermography 830 matched filters, SLM 777 matrix-matrix switches, SLM 798 Mauguin behavior... 

Hexagonal mesophases can be recognized by their typical fan-shape texture (Fig. 7a). Lamellar mesophases typically show oily streaks with inserted maltese crosses (Fig. 7b). The latter are due to defects, called confocal domains, that arise from a concentric rearrangement of plane layers. In some lamellar mesophases these defects prevail. Hence no oily streaks occur but maltese crosses are the dominant texture (Fig. 7c). 

Fig. 9 Textures of the columnar phases of compound 34b. Pseudo-focal conic texture at 92 °C of the Colhd phase (bottom) and at 74 °C in the body-centred orthorhombic columnar phase (top). In order to increase the dynamic range of the photographs various photos with different exposure times have been superimposed. The black Maltese cross is perfectly dark in the centre for the Colhd- In the low temperature phase undulation of the columns produces birefringence in the dark branches...

Stirring 0.7 wt% surfactant in water for several hours produced a turbid bluish-white system. A specimen under the microscope and between crossed polarizers revealed numerous birefringent spherulites 5 to lOOy in diameter, with characteristic Maltese crosses. Similar textures were also observed with 0.3 or 1.0 wt% NaCl present. Figure 1 is a photomicrograph of typical spherulites together with so-called myelinic figures (17b), which are caused by interference phenomena. 

Crosspolarized photomicrographs of PEO 1, EO-Is-EO 2, EO-Is-EO 3, and EO-Is-EO 4 films cast from 1% benzene solutions at 30° C are presented in Figure 1. The spherulitic texture with negative birefringence became less perfect and led to a less clear Maltese cross as the fraction of amorphous Is segment increased. When the EO fraction constituted less than 50%, the texture was not clearly resolved by light microscopy. 

Figure 3. Typical optical textures ofa lamellar phase (a) mosaic oily streaks, (b) Maltese crosses.

It is well known that PEO spherulites have a Maltese cross extinction pattern and a veiy fine spherulite texture as observed under POM (Ketabi and Lian, 2012 Choi and Kim, 2004 Xi et al., 2005 Choi, 2004) (refer to Figure 9). Meanwhile, under SEM, the image of pure PEO shows waving smooth and uniform stmeture without any phase separation (Johan et al., 2011). 

Under polarization microscopa, liquid crystal exhibit Maltese-crosses optical textures, while crystals produced more angular (needle-like, rhombus, or dot-shapa) diffraction patterns The two states also reacted differently to pressure experiments, with the liquid-crystals dividing into smaller Maltese-cross droplets, while crystals fractured imer duress [Xu XH et al 2009, 2011a]. 

As well known, nanofillers often have significant influence on the crystal morphology of a semicrystalhne polymer. As shown in Figure 5.5, various spheruHte morphologies of PET and PET /clay nanocomposites have been characterized with polarized optical microscopy [21]. Neat PET demonstrates a well-defined spheruHte texture with a fibril pattern and a maltese cross at 200 °C. However, the maltese cross is not observed at higher crystallization temperature. PET/clay nanocomposites exhibited typical crystalline morphologies indicating that day exhibits a... 

EHI looks like fingerprint textures at low frequencies and like Maltese crosses at high frequencies (Fig. 5.21). 

Fig. 5.42 Polarized light micrographs of a molded nylon cross section show a nonspherulitic skin (top in A) and rounded isolated spherulites in the transition zone. A classical Maltese cross extinction pattern is observed with black brushes showing the radial texture within the spherulites (B). (See also Fig. 1.3 in color section.)...

Fig. 1.3 A thin section of bulk crystal- lized nylon, in polarized light, reveals a bright, binefitigent and spherulitic texture. At high magnification a classic Maltese cross pattern is seen, with black crossed arms aligned in the position of the crossed polarizers. 

The lamellar liquid crystalline phase consists of several bilayers of surfactant molecules and shows a mosaic-type texture (with Maltese crosses) when viewed under polarizing light. Low-angle X-ray diffraction shows spacing characteristic of a lamellar structure and the repeat unit is the back-to-back bilayer of the surfactant molecules with their alkyl groups in contact. The phase is built up from these flexible bilayers which are arranged parallel to each other [25]. The surfactant bilayer... 

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