Refractive index, and optical

Ferroelectric materials are capable of being polarized in the presence of an electric field. They may exhibit considerable anomalies in one or more of their physical properties, including piezoelectric and pyroelectric coefficients, dielectric constant, and optoelectronic constant. In the latter case, the transmission of light through the material is affected by the electric field, which produces changes in refractive index and optical absorption coefficient. Varying the applied field changes the phase modulation. 

The temperature for measuring physical parameters, specific gravity, refractive index, and optical rotation is critical for obtaining accurate results. 

The Pharmacopea and the Essential Oil Association of the United States require the following analyses as an index of oil purity refractive index, optical rotation, refractive index and optical rotation of a 10% distillate, specific gravity, aldehyde content, evaporation residue and ultraviolet absorption spectrum (Kesterson et al. 157 and Sale 29). 

The electron effective mass in GaN is now reasonably well established by cyclotron resonance measurements [14-16] asm, = (0.22 0.0 l)m, and the low frequency dielectric constant (appropriately averaged spatially) e(0) = 9.5 0.2, from infrared refractive index and optic phonon energy measurements [17]. We can therefore derive a reliable value for the hydrogenic donor ionisation energy of EDH = (33.0 1.5) meV which compares well with IR absorption measurements, giving Ed = (35 1) meV [18] (see below). The discrepancy is readily explained in terms of a small chemical shift. 

A dithienylethene-based liquid crystal material has been synthesized. This provides a morphologically stable, photoresponsive glassy nematic system in which the refractive index and optical birefringence can be modulated by photochemical means (Equation 7) <2004CSR85>. 

Harvesting time affects some chemical properties of oil, as is shown in Table 5.5. Furthermore, smaller differences have been observed in other properties such as specific gravity, refractive index and optical rotation in line with harvesting time (L6pez, 1995). 

Among the different analytical variables listed in Table 5.10, specific gravity, refractive index and optical rotation are widely used as quality indexes. The values of these properties allow us to estimate the (/-limonene content, general composition and adulterations in essential oils. Aldehyde content is also a widely used index in the characterization of essential oils, because it is a measure of the aromatic fraction values increase in mature fruit and decrease during fruit storage (Lopez, 1995). The UV absorption index indicates general quality and adulterations, and shows differences between the different types of essential oils (Lopez, 1995). 

The history of optical science closely parallels the history of the development of optical glasses. Development of early telescopes and microscopes immediately forced a search for new optical glasses with appropriate refractive index and optical dispersion characteristics. It can be argued that the development of modem astronomy, biology, and medical science were controlled by the ability of glass makers to develop glasses with the appropriate optical properties. 

The ellipsometric technique has been used for the estimation of thickness, refractive index and optical dielectric constants of a conducting polymer film [89]. These conducting polymer films have been used for the fabrication of electrochromic and glucose biosensing... 

Nonmetallic inorganic materials are widely used for optical purposes lenses, pigments, interference filters, laser hosts, luminescent coatings, displays, solar cells, fiber optics, lamp bulbs, and tubes. For optical applications use is made of the refractory index, light absorption, luminescence, and nonlinear optical behavior of materials. These are intrinsic but may depend on the concentration of impurities. Refraction index and optical absorptivity in insulators are atomic properties and are only indirectly related to the structure, but the structure affects the selection rules and the term splitting in the atomic chromophores. The coordination number determines the intensity and wavelength of absorption and... 

Medenbach O, Dettmar D, Shannon RD et al (2001) Refractive index and optical dispersion... 

Two groups have used physical measurements e.g. density, viscosity, refractive index, and optical rotation) to determine the compositions of solutions of water-sucrose-D-glucose (or invert sugar) at various temperatures. The diffusion coefficient for self-diffusion of D-fructose in an aqueous system has been measured over a range of concentrations and temperatures. The yields of trapped electrons and radicals have been determined following y-irradiation of frozen aqueous solutions of sugars. ... 

Terpenoids can be analyzed by the usual methods. For the volatile members of the family, gas chromatography-mass spectrometry (gc-ms) is a particularly useful tool. In laboratories (e.g., those in the major fragrance companies), which are accustomed to analyzing mixtures of volatile terpenoids, gc-ms is the major analytical technique employed and such laboratories will have extensive libraries of mass spectra of terpenoids to assist in this. However, the mass spectral fragmentation patterns of closely related terpenoids are often so similar as to render definitive identification by ms alone, impossible. For these materials and those for which there is no reference (e.g., compounds newly isolated from nature), nuclear magnetic resonance (nmr) spectroscopy is the analytical tool of choice. Physical techniques, e.g., density, refractive index, and optical rotation, are relatively inexpensive and prove useful in quality control. 

As Smith and Gay [1958] have emphasized, the detailed study of a plagioclase specimen requires single crystal, powder diffraction, chemical analysis, refractive index, and optical orientation data at least. This is similarly true for the alkali feldsparsi especially since some optical properties are sensitive to compositional impurities as much as structural state. It would seem that such a careful study of feldspars in the fine sand fraction may repay handsome... 

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