Sodium lights

Polyarylates have been employed for electrical and electronic components, firefighter helmets, and appHcations requiring higher heat-deflection temperatures than PC resins. Polyarylates were first used for lighting, especially for small automotive lenses and sodium light outdoor lamps. However, the inherent yellow color and heat-induced darkening have limited appHcations. 

This apparatus can only be used with sodium light, as for quantitative results light of definite refrangibility must be used. A Bunsen lamp of convenient construction, into the flame of which a little common salt can be introduced on a platinum wire, is placed about 4 or 5 inches from the... 

If expressed for white light instead of sodium light, it is expressed... 

The refractive index also varies with the wavelength, and the wavelength at which it is measured must also be specified. Yellow sodium light for illumination is not very handy. For that reason, commercial, low-cost refractometers have built-in compensators and filters that enable the use of ordinary white light. The resulting refractive index is that which would have been obtained had a sodium light source been used. 

The sample tube of the polarimeter is rinsed with the drug solution (2.5% w/v) and filled up with the same solution. The end glass-windows are closed properly. The angle of rotation of ibuprofen is now measured at 19.5° to 20.5°, using the D-line of polarized sodium light. Take at least five measurements and determine the mean value. 

Important DHP s are light sensitive. Avoid daylight and work in a dark room illuminated by yellow light (e.g., sodium light source). 

Table 8.17. Concentration, density q, and refractive index n (20 °C, sodium light source) of sucrose solutions...

M. Erofejeff8 found the refractive indices of ammonium sulphate for lithium and sodium light for vibrations parallel to all three axes and A. E. H. Tutton found for the o, j8, and y indices of refraction, where the vibrations are respectively parallel to the o, b, a axes, at ordinary temp., say 15° ... 

The index of refraction of soln. of the alkali nitrates at 20° for sodium light is ... 

Octahedral sulphur is a brittle solid of hardness approximately 2-3 the colour is lemon-yellow at the ordinary temperature but darkens somewhat on warming, whilst at —50° C. it almost disappears, leaving the solid practically colourless 6 the refractive index for sodium light is 2-08,7 the mean specific heat is 0-170,8 and the coefficient of cubic... 

The refractive index for sodium light is 1-00001 at 0° C. and 760 mm.1 The electrical conductivity is exceedingly small.2 The specific... 

This very high compressibility is to be expected from the structure of the crystal which, as seen above, is molecular rather than ionic and moreover contains large open spaces between the atoms. The refractive indices at 17° C. are 1-733 for sodium light and 1-748 for lithium light.2 Klocke observed 3 that for yellow light the sublimed crystals exhibit double refraction, but this could not be confirmed by Brauns.4... 

The indices of refraction along the three axes for sodium light are 8 a = 1-629, j3 = 1-663 and y —1-701. The mineral is soluble in hydrochloric acid forming a blue solution which reddens on dilution. A... 

Solvents were dried over sodium (light petroleum, bp 40-60°C, toluene) or sodium-benzophenone (diethyl ether, THF). Sodium amide, hexamethyl-disilazane, lithium triethylhydroborate(l —), and hydrogen tetrafluoro-borate(l —) diethyl ether complex were obtained from Aldrich and used as supplied. 

The absolute index for all ordinary transparent substances is greater than 1 (see Table 1) but there are some special cases (X-rays and light in metal films, which are discussed below) for which the index of refraction is less than unity. Since the absolute index for air exceeds unity by less than 0.0003, the relative indices for solids and liquids in air are very nearly equal to their absolute indices. It should be noted that since the refractive mdex vanes with the wavelength, any exact statement of its value must specify the wavelength to which it refers in Tables it is usually given for sodium light of frequency 5.893A. See also Dispersion. 

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