Crystalline coefficient

MAP has a non-centrosymmetric structure (24) P2- leading to four non-vanishing crystalline nonlinear coefficients. According to the previously defined two-level model, there are also four non-vanishing molecular nonlinearity coefficients which are linearly related to the crystalline coefficients. (3)... 

Age (weeks) Dose Ash Corr d Corr d Ca Corr d P Corr d Crystallinity Coefficient... 

Table 19.2 shows the effect of temperature of synthesis of BN on various properties, namely, surface area, crystallinity, coefficient of friction, and oxygen content [40]. It may be noted that vhth increase in synthesis temperature, the coefficient of friction decreases. Typical properties of (h)BN relevant to its use as a filler are summarized in Table 19.1. 

In (6), fa is the molecular orientation factor, K, and 0D are the maximum crystallization rate, maximum rate temperature, and crystallization half-width, respectively, and C is the stress-induced crystallinity coefficient (see [7]). 

Below Tg the material is hard and rigid with a coefficient of thermal expansion equal to roughly half that of the liquid. With respect to mechanical properties, the glass is closer in behavior to a crystalline solid than to a... 

Many of the physical properties are not affected by the optical composition, with the important exception of the melting poiat of the crystalline acid, which is estimated to be 52.7—52.8°C for either optically pure isomer, whereas the reported melting poiat of the racemic mixture ranges from 17 to 33°C (6). The boiling poiat of anhydrous lactic acid has been reported by several authors it was primarily obtained duriag fractionation of lactic acid from its self-esterification product, the dimer lactoyUactic acid [26811-96-1]. The difference between the boiling poiats of racemic and optically active isomers of lactic acid is probably very small (6). The uv spectra of lactic acid and dilactide [95-96-5] which is the cycHc anhydride from two lactic acid molecules, as expected show no chromophores at wavelengths above 250 nm, and lactic acid and dilactide have extinction coefficients of 28 and 111 at 215 nm and 225 nm, respectively (9,10). The iafrared spectra of lactic acid and its derivatives have been extensively studied and a summary is available (6). 

Only certain types of crystalline materials can exhibit second harmonic generation (61). Because of symmetry considerations, the coefficient must be identically equal to zero in any material having a center of symmetry. Thus the only candidates for second harmonic generation are materials that lack a center of symmetry. Some common materials which are used in nonlinear optics include barium sodium niobate [12323-03-4] Ba2NaNb O lithium niobate [12031 -63-9] LiNbO potassium titanyl phosphate [12690-20-9], KTiOPO beta-barium borate [13701 -59-2], p-BaB204 and lithium triborate... 

Another parameter of relevance to some device appHcations is the absorption characteristics of the films. Because the k quantum is no longer vaUd for amorphous semiconductors, i -Si H exhibits a direct band gap (- 1.70 eV) in contrast to the indirect band gap nature in crystalline Si. Therefore, i -Si H possesses a high absorption coefficient such that to fully absorb the visible portion of the sun s spectmm only 1 p.m is required in comparison with >100 fim for crystalline Si Further improvements in the material are expected to result from a better understanding of the relationship between the processing conditions and the specific chemical reactions taking place in the plasma and at the surfaces which promote film growth. 

The effect of copolymer composition on gas permeability is shown in Table 9. The inherent barrier in VDC copolymers can best be exploited by using films containing Htde or no plasticizers and as much VDC as possible. However, the permeabiUty of even completely amorphous copolymers, for example, 60% VDC—40% AN or 50% VDC—50% VC, is low compared to that of other polymers. The primary reason is that diffusion coefficients of molecules in VDC copolymers are very low. This factor, together with the low solubiUty of many gases in VDC copolymers and the high crystallinity, results in very low permeabiUty. PermeabiUty is affected by the kind and amounts of comonomer as well as crystallinity. A change from PVDC to 50 wt °/ VC or 40 wt % AN increases permeabiUty 10-fold, but has Httle effect on the solubiUty coefficient. 

Increased crystallinity can reduce permeabiHty values because the crystal regions of a polymer are impenetrable ia most semicrystaUine polymers. Hence, the average value of the solubiHty coefficient S is reduced. It also means that movement must occur around the crystaUites, which means that a longer distance must be traveled. This lowers the effective value of D. 

Chlorine dioxide is soluble in water, forming a yellow to yeUow-green color solution that is quite stable if kept cool and in the dark. Various crystalline hydrates of chlorine dioxide have been described including a hexahydrate (19), an octahydrate (20), and an orange colored decahydrate (21). The partition coefficient between water and CIO2 gas is about 21.5 at 35°C and 70.0 at 0°C (22). Data on the solubiUty of chlorine dioxide in water at various... 

Coefficient of Variation One of the problems confronting any user or designer of crystallization equipment is the expected particle-size distribution of the solids leaving the system and how this distribution may be adequately described. Most crystalline-product distributions plotted on arithmetic-probability paper will exhibit a straight line for a considerable portion of the plotted distribution. In this type of plot the particle diameter should be plotted as the ordinate and the cumulative percent on the log-probability scale as the abscissa. 

Of greater interest in recent years have been the peculiar piezolectric properties"" of polyfvinylidene fluoride). In 1969 it was observed" that stretched film of the polymer heated to 90°C and subsequently cooled to room temperature in a direct current electric field was 3-5 times more piezoelectric than crystalline quartz. It was observed that the piezolectric strain coefficients were higher in the drawn film and in the normal directions than in the direction transverse to the film drawing. 

Damping coefficient 7) Density (g/cm ) 10) Crystalline melting point 11) Damping coefficient... 

Following Ref. 122, we consider the adsorption of associating hard spheres, Eq. (60), with d = 0.45, a = 0.09 in a slit-like pore with crystalline walls. A weakly associated fluid and a highly associated fluid have been studied. The weakly associated fluid was characterized by the coefficient A (cf. Eq. (79)) equal to 1, whereas in the case of the highly associated fluid A = 100. 

These techniques help in providing the following information specific heat, enthalpy changes, heat of transformation, crystallinity, melting behavior, evaporation, sublimation, glass transition, thermal decomposition, depolymerization, thermal stability, content analysis, chemical reactions/polymerization linear expansion, coefficient, and Young s modulus, etc. 

Draw ratio Degree of crystallinity Lattice disorder coefficient (k) Average crystallite size perpendicular to the crystallographic plane (hkl) Dhki (nm) ... 

Poly acetals are highly crystalline polymers. The number of repeating units ranges from 500 to 3,000. They are characterized by high impact resistance, strength, and a low friction coefficient. 

Acetal This crystalline plastic is strong, stiff, and has exceptional resistance to abrasion, heat, chemicals, creep and fatigue. With a low coefficient of surface friction, it is especially useful for mechanical products such as gears, pawls, latches, cams, cranks, plumbing parts, etc. It is chrome platable. 

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