Dispersing medium

The latter condition corresponds to the phase matching requirement already mentioned—the wavelength and direction of the material polarization wave must match those of the new EM wave as closely as possible. However, for all Class I spectroscopies, this condition is automatically achieved because of quadrature. In fact, this is tnie for all quadrature spectroscopies—the Class I spectroscopies being the principal such, but, as noted, it is a nontrivial requirement in the nonquadrature Class II spectroscopies, particularly in optically dispersive media. 

Triaryl phosphates are also used on a large scale as flame-retardant hydrauhc fluids (qv), lubricants, and lubricant additives (see Lubrications and lubricants). Smaller amounts are used as nonflammable dispersing media for peroxide catalysts. 

Some typical dispersion polymerization recipes and the electron micrograph of the uniform polymeric particles with Recipe I are given in Table 5 and Fig. 10, respectively. As seen in Table 5, the alcohols or alcohol-water mixtures are usually utilized as the dispersion media for the dispersion polymerization of apolar monomers. In order to achieve the monodispersity in the final product, a costabilizer can be used together with a primary steric stabilizer, which is usually in the polymeric form as in... 

We also studied the effect of initiator on the dispersion polymerization of styrene in alcohol-water media by using a shaking reactor system [89]. We used AIBN and polyacrylic acid as the initiator and the stabilizer, respectively. Three different homogenous dispersion media including 90% alcohol and 10% water (by volume) were prepared by using isopropanol, 1-butanol, and 2-... 

Paine et al. [85] extensively studied the effect of solvent in the dispersion polymerization of styrene in the polar media. In their study, the dispersion polymerization of styrene was carried out by changing the dispersion medium. They used hydroxypropyl cellulose (HPC) as the stabilizer and its concentration was fixed to 1.5% within a series of -alcohols tried as the dispersion media. The particle size increased from only 2.0 /itm in methanol to about 8.3 /itm in pentanol, and then decreased back to 1 ixm in octadecanol. The particle size values plotted against the Hansen solubility parameters... 

Nozzle exit velocity Dispersion media and rate... 

The existence of yield stress Y at shear strains seems to be the most typical feature of rheological properties of highly filled polymers. A formal meaing of this term is quite obvious. It means that at stresses lower than Y the material behaves like a solid, i.e. it deforms only elastically, while at stresses higher than Y, like a liquid, i.e. it can flow. At a first approximation it may be assumed that the material is not deformed at all, if stresses are lower than Y. In this sense, filled polymers behave as visco-plastic media with a low-molecular and low-viscosity dispersion medium. This analogy is not random as will be stressed below when the values of the yield stress are compared for the systems with different dispersion media. The existence of yield stress in its physical meaning must be correlated with the strength of a structure formed by the interaction between the particles of a filler. 

It seems that results rather close in their meaning should be obtained, provided that monodisperse polymers are taken as dispersion media. Investigations into dynamic (viscoelastic) properties of such liquids with highly active filler have shown that [6],... 

Though experimental data on suspensions of fibers in Newtonian dispersion media give more or less regular picture, a transition to non-Newtonian viscoelastic liquids, as Metzner noted [21], makes the whole picture far or less clear. Probably, the possibility to make somewhat general conclusions on a longitudinal flow of suspensions in polymer melts requires first of all establishing clear rules of behavior of pure melts at uniaxial extension this problem by itself has no solution as yet. 

Pigments are generally labile as free molecules and the natural and simplest way to stabilize their function is to form micelles (oil-in-water or water-in-oil emulsions, depending on the major dispersion media). 

Not all colloid systems are stable. The most stable involve solid dispersion media, since movement through a solid host will be slow. Emulsions also tend to be stable think, for example, about a glass of milk, which is more likely to decompose than undergo the destructive process of phase separation. Aerosols are not very stable although a water-based polish generates a liquid-in-air colloid, the particles of liquid soon descend through the air to form a pool of liquid on the table top. Smoke and other solid-in-gas aerosols are never permanent owing to differences in density between air and the dispersed phase. 

P. M. Goorjian, and A. Taflove, "Direct time integration of Maxwells equations in nonlinear dispersive media for propagation and scattering of femtosecond electromagnetic solitons," Opt. Lett 17, 180-182 (1992). 

The colloidal particles are often deposited on metallic electrodes in the form of adsorbed coatings. Rubber and graphite coatings can be formed in this way, using solvent mixtures (water-acetone) as the dispersion media. The advantage of this method is that additives can firmly be codeposited with, for example, rubber latex. Thermionic emitters for radio valves are produced in a similar manner. The colloidal suspensions of alkaline earth carbonates are deposited electrophoretically on the electrode and are later converted to oxides by using an ignition process. 

The loss of observable THG in the far field with tight focusing of the beam in homogenous normal dispersion media can be described with the paraxial wave equation [Equation (4.2)] assuming slow spatial variation of electric field amplitudes along the beam propagation direction (z direction). The solution of the paraxial wave equation for the amplitude of third harmonic (A3 J can be written as follows (Boyd 1992) ... 

So far, we have prepared and tested many kinds of colloids, mainly in nonaqueous suspensions with combinations of metals or alloys as a dispersed phase and organic liquids as the dispersion media, without the use of any dispersing agents these are listed in Table 9.4.1. We next give some examples of transmission electron micrographs of nanoparticles produced by an aerosol method. A sample for TEM measurement was obtained by dropping colloidal suspension onto a Cu mesh coated with an evaporated carbon film of 10 nm thickness. Many colloids were so unstable... 

Supercritical carbon dioxide has been used as a dispersing medium for the manufacture and processing of polymeric materials. The process allows for the synthesis of high molar mass acrylic polymers in the form of micrometer-sized particles with a narrow size distribution. This procedure represents an environmentally responsible alternative to aqueous and organic dispersing media for heterogeneous dispersion polymerizations (Fox, 1994). 

Thus, a susceptibility that depends on frequency and wave vector implies that the relation between P(x, t) and E(x, t) is nonlocal in time and space. Such spatially dispersive media lie outside our considerations. However, spatial dispersion can be important when the wavelength is comparable to some characteristic length in the medium (e.g., mean free path), and it is well at least to be aware of its existence it can have an effect on absorption and scattering by small particles (Yildiz, 1963 Foley and Pattanayak, 1974 Ruppin, 1975, 1981). 

The effects associated with the influence of the phase border are especially obvious in heterogeneous polymer systems, where both components are of a polymeric nature. Such systems include polymer blends and polymers filled with polymeric filler. These two types of systems differ in that in blends it is difficult to distinguish between the two polymers as a disperse phase and dispersion media due to uniform distribution of both components in the volume. 

The first two terms on the right-hand side of Eq. (15) are conventionally ascribed to dispersive media [62, p. 9], while the third term is the displacement current density id [66, Chap. 9], The latter may be easily observed in material media (air) see, for instance, Carver and Rajhel [68] and Bartlett and Corle [69]. It is... 

Gallagher, P.A., S. Murray, X. Wei, et al. 2002. An evaluation of sample dispersion media used accelerated solvent extraction for the extraction and recovery of arsenicals from LFB and DORM-2. J. Anal. At. Spectrom. 17 581-586. 

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