Polarizing microscopy. See

A further advantage of the IGSS method is that its reaction product can clearly be differentiated from immunoenzyme products with epi-polarization microscopy (see Chapter 30). 

Figure 1.10. Fluorescence microscopy pictures of two 1500-nm long zeolite L crystals containing DSC. Excitation with unpolarized light at 480 nm. Left Unpolarized observation. Middle and right Linearly polarized observation. The arrows indicate the polarization direction. (See insert for color representation.)...

FIGURE 10.10 An experimental system of tip-enhanced CARS microscopy. See the text for detail. ND nentral-density filter, P polarizer, DM dichroic mirror, BE beam expander, BS beam splitter, APD avalanche photo diode. 

Ferroelectric domains have been visualized in the ferroelectric phase in sbn with high resolution piezo-response force microscopy (see Figure 15.8) [23], The domains are found to be needlelike with lengths in the range of 10 to 500 nm and are oriented along the polar c-axis. The dynamics of the domain walls under externally applied electric fields or heating are expected to influence the polarization especially at low frequencies (see domain wall polarization, Chapter 1) [24],... 

Therefore, local dissolution and recrystallization seem to play an important role in the gas uptake mechanism in these type of sensor materials. The coordination of SO2 to the platinum center (and the reverse reaction) is therefore likely to take place in temporarily and very locally formed solutes in the crystalline material, whereas the overall material remains crystalline. The full reversibility of the solid-state reaction was, furthermore, demonstrated with time-resolved solid-state infrared spectroscopy (observation at the metal-bound SO2 vibration, vs= 1072 cm-1), even after several repeated cycles. Exposure of crystalline samples of 26 alternat-ingly to an atmosphere of SO2 and air did show no loss in signal intensities, e.g. due to the formation of amorphous powder. The release of SO2 from a crystal of 27 was also observed using optical cross-polarization microscopy. A colourless zone (indicative of 26) is growing from the periphery of the crystal whereas the orange colour (indicative for 27) in the core of the crystal diminishes (see Figure 9). 

Some years after liquid crystalline properties were described for the (perfluoro-decyl)decane 6 [71], the mesomorphic nature of the phase exhibited by 5e and 5f at temperatures above their solid-solid transitions were also recognized [77]. In case of 6, polarizing microscopy and X-ray experiments prove the existence of a SmB mesophase in the temperature range 38-61 °C, see Table 3. 

In contrast to specimens that were not prepared by extrusion or injection molding but were heated and pressed without appreciable shear stress, there is no significant contrast of the LC-poor and LC-rich phases in SEM of broken samples. This is true, independent of the composition. The existence of different phases, however, can be shown with polarized light microscopy (see below). 

The piezoelectric hysteresis loops have been studied additionally to above dielectric hysteresis. This kind of loop is shown on Fig. 2.17. It has been recorded on PZT nanotube with outer diameter 700 and 90 nm wall thickness with the help of piezoatomic force microscopy (see Refs. [42, 43]). The obtained loop is the direct evidence of ferroelectric properties of the nanotube. Square form of the loop speaks about sharp polarization switching at coercive voltage 2 V. The residual (at zero voltage) piezoelectric coefficient d ff is of the same order as for the thin PZT film. 

Spin-lattice relaxation time increased continuously as a fimction of time, passing from 4000 ms to 8500 ms. It was possible to see two different evolutions. Ti increased rapidly during the two first days and slowed down after this time. Such a curve can be fitted with a power law model. The evolution was the same as for crystal size during Ostwald Ripening. The power law exponent determined for this system was 0.098, which is lower than the 0.2 to 0.3 which can be found for the evolution of crystal size followed by polarized microscopy. The actual deviation was due to the fact that we measured spin-lattiee relaxation times and not crystal size directly. However, the fact that we retained the power law model led us to expect a relationship between crystal size and spin-lattice relaxation time. 

Microscopy with polarized light (see Section 3.2.4.2) can identify FeS2 (pyrite and marcasite), Si02 (quartz), and FeCOs (iron spar) by differentiation of the reflectance and color in a very easy way. But also change of light (intensity, wavelength), detection of the individual refraction index, and identification of crystalline structures (e.g., needles) can help to determine the types of minerals and their volume fraction. 

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