Temperature refractive indices

In the case of chemically sensitive devices, the interaction of a given volatile compound or ions in solution can produce one of the following changes mass, charge, temperature, refractive index, magnetic field, work function. For each of these changes suitable transducers are now available. 

In recent years, cyclic polymers (also referred to as polymer rings or macrocycles) became easier to prepare. By a number of different approaches and advances in cyclization techniques, a wide range of novel cyclic polymers have been prepared in good yields [10]. In contrast to linear polymers, cyclic polymers are topologically distinct species, and all monomer units of cyclic polymers are chemically and physically equivalent. This equivalence is due to the fact that their properties are not affected by the nature of the end groups, since cyclic polymers have no chain ends. They include the radius of gyration, intrinsic viscosity, translational friction coefficient, critical solution temperature, refractive index, density, dipole moment, glass transition temperature, and surface property [11]. 

FIGURE 2 Room temperature refractive index of wurtzite GaN, after [44],... 

Temperature of the system is also an important parameter since the viscosity of the polymer solutions has significant dependence on the temperature. Refractive index and viscometric detectors are the most common detectors used in GPC, and their responses are both dependent on the temperature. Both of these detectors have relatively low sensitivity, resulting in the necessity to use concentrated polymer solutions, which in turn increases the sample... 

What physical meaning should one attach to the velocity potential For the flow of an ideal, frictionless fluid, the velocity potential has no physical meaning whatever. To illustrate this, consider the steady flow of a frictionless, constant-density fluid in a horizontal pipe see Fig. 10.3. (Such a frictionless fluid, once started in motion by some external force, would continue moving forever, because there is no force to stop it.) For such a frictionless fluid, the velocity is uniform over the cross section perpendicular to the flow. From Bernoulli s equation we can see that there is no change with distance of pressure, velocity, or elevation, and by straightforward arguments we can show that there is no change of temperature, refractive index, dielectric constant, or any other measurable property. But from Eq. 10.7 we know that, because is constant, there is a steady decrease of (f> in the x direction. Thus the velocity potential for a perfect fluid (f> is not a function of any measurable physical property of the fluid. 

Compound Formula Mol. weight Elementary analysis (%) Epoxy oxygen content(%) Boiling temperature Refractive index... 

Before sample preparation the sample should be thoroughly blended. In the case of grains and powdered substances, liquids, and slurries, this reduces the possibility of stratification of the material, which can be a serious source of error. Stratification can occur in liquids due to differences in temperature, refractive index, composition, density, and other factors. Blending of forages means ensuring that the correct proportion of leaves to stems is maintained, and that the sample submitted... 

The refractive index of a liquid is recorded as where t is the temperature at which the measurement is made, and D refers to the wave length of the D line of sodium. As already pointed out, it is usual to determine both the refractive index and the density of the liquid at 20° in any case they should be determined at the same temperatme. These two constants are useful in assisting the characterisation of a pure hquid they are particularly valuable for ahphatic hydrocarbons and similar compounds where the methods of characterisation by the formation of solid derivatives are not entirely satisfactory. 

In the flask were placed 10.0 g of the propargylic amine (see Chapter lIII-5, Exp. 1). The air in the flask was replaced with nitrogen and a solution of 0.01 mol of KO-tert.-Ci,H,3 in 10 g of THF (free from hydroperoxide) was added. The mixture was warmed at about 40 C. A weakly exothermic reaction was observed and the temperature rose to about 45°C. After 1-2 min the gel originally present, had disappeared almost completely and a brown solution had formed. The refractive index of the solution (note 1) was measured after intervals of about 2 min. After the... 

Note 1. At higher temperatures the tertiary chloride undergoes a rearrangement, catalysed by CuCl, giving H2C=C(C1)CH=CH2. In these cases the refractive index of the crude product is much higher. 

TABLE 5.19 Refractive Index, Viscosity, Dielectric Constant, and Surface Tension of Water at Various Temperatures... 

The refractive index of CCI4 at 20°C and 589 nm, the D line of the sodium spectrum, is 1.4607. At this temperature the density of this compound is 1.59 g cm . Use this information to calculate a for CCI4. Criticize or defend the following proposition The prediction that = f(R/X) may have been premature. The consideration of Eq. (10.3) which led to this conclusion could just as well predict = f(a /X). 

By an assortment of thermodynamic manipulations, the quantities dn/dp and [N (d G/dp )o] can be eliminated from Eq. (10.48) and replaced by the measurable quantities a, /3, and dn/dT the coefficients of thermal expansion, isothermal compressibility, and the temperature coefficient of refractive index, respectively. With these substitutions, Eq. (10.48) becomes... 

The physical constants of furfuryl alcohol are Hsted in Table 1. When exposed to heat, acid or air the density and refractive index of furfuryl alcohol changes owing to chemical reaction (51), and the rate of change in these properties is a function of temperature and time of exposure. 

Solution Polymers. Acryflc solution polymers are usually characterized by their composition, solids content, viscosity, molecular weight, glass-transition temperature, and solvent. The compositions of acryflc polymers are most readily determined by physicochemical methods such as spectroscopy, pyrolytic gas—liquid chromatography, and refractive index measurements (97,158). The solids content of acryflc polymers is determined by dilution followed by solvent evaporation to constant weight. Viscosities are most conveniently determined with a Brookfield viscometer, molecular weight by intrinsic viscosity (158), and glass-transition temperature by calorimetry. 

Whereas the OVD, PCVD, and MCVD processes build a refractive index profile layer by layer, the VAD process uses gaseous constituents in the flame to control the shape and temperature distribution across the face of the growing soot boule. 

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