Atmosphere refractive index

For microwave band, troposphere atmospheric refractive index N is ... 

By the definition of atmospheric duct, when the vertical gradient of atmospheric refraction index is equal to -0.157 m", the atmospheric duct is formed, at the same time corresponding height z is duct height so... 

The reaction mixture is heated and allowed to reflux, under atmospheric pressure at about 100°C. At this stage valve A is open and valve B is closed. Because the reaction is strongly exothermic initially it may be necessary to use cooling water in the jacket at this stage. The condensation reaction will take a number of hours, e.g. 2-4 hours, since under the acidic conditions the formation of phenol-alcohols is rather slow. When the resin separates from the aqueous phase and the resin reaches the requisite degree of condensation, as indicated by refractive index measurements, the valves are changed over (i.e. valve A is closed and valve B opened) and water present is distilled off. 

Bromine (128 g., 0.80 mole) is added dropwise to the well-stirred mixture over a period of 40 minutes (Note 4). After all the bromine has been added, the molten mixture is stirred at 80-85° on a steam bath for 1 hour, or until it solidifies if that happens first (Note 5). The complex is added in portions to a well-stirred mixture of 1.3 1. of cracked ice and 100 ml. of concentrated hydrochloric acid in a 2-1. beaker (Note 6). Part of the cold aqueous layer is added to the reaction flask to decompose whatever part of the reaction mixture remains there, and the resulting mixture is added to the beaker. The dark oil that settles out is extracted from the mixture with four 150-ml. portions of ether. The extracts are combined, washed consecutively with 100 ml. of water and 100 ml. of 5% aqueous sodium bicarbonate solution, dried with anhydrous sodium sulfate, and transferred to a short-necked distillation flask. The ether is removed by distillation at atmospheric pressure, and crude 3-bromo-acetophenone is stripped from a few grams of heavy dark residue by distillation at reduced pressure. The colorless distillate is carefully fractionated in a column 20 cm. long and 1.5 cm. in diameter that is filled with Carborundum or Heli-Pak filling. 4 hc combined middle fractions of constant refractive index are taken as 3-l)romoaccto])lu iu)nc weight, 94 -100 g. (70-75%) l).p. 75 76°/0.5 mm. tif 1.57,38 1.5742 m.]). 7 8° (Notes 7 and 8). 

In order to understand RAIR spectroscopy, it is convenient to model the experiment (see Fig. 4). Consider a thin film with refractive index n =n ik and thickness d supported by a reflecting substrate with refractive index ni = ri2 — iki- The refractive index of the ambient atmosphere is o- Infrared radiation impinges on the film at an angle of incidence of 6 . The incident radiation can be polarized parallel to or perpendicular to the plane of incidence. 

In order to compensate for the distortions in the wavefront due to the atmosphere we must introduce a phase correction device into the optical beam. These phase correction devices operate by producing an optical path difference in the beam by varying either the refractive index of the phase corrector (refractive devices) or by introducing a variable geometrical path difference (reflective devices, i.e. deformable mirrors). Almost all AO systems use deformable mirrors, although there has been considerable research about liquid crystal devices in which the refractive index is electrically controlled. 

If a laser beam produces in the outer atmosphere a spectrum spanning from the ultraviolet to at least the red, then the return light will follow different optical paths depending on the wavelength (Fig. 19). The air refraction index is a function of air temperature T and pressure P ... 

Monohydrate, Ba(0H)2 H20 is a white powder density 3.743 g/cm shght-ly soluble in water soluble in dilute mineral acids. Octahydrate, Ba(0H)2 8H20 is a colorless monoclinic crystal density 2.18 g/cm at 16°C refractive index 1.50 melts at 78°C vapor pressure 227 torr loses seven molecules of water of crystallization when its solution is boiled in the absence of atmospheric CO2 forming solid monohydrate further heating produces anhydrous Ba(OH)2 melting at 407°C readily dissolves in water (3.76 g/100 g at 20°C and 11.7 g/100 g at 50°C) aqueous solution highly aUtahne also soluble in methanol shghtly soluble in ethanol insoluble in acetone. 

Colorless and odorless gas refractive index 1.000036 at 0°C and 1 atm density of the gas at 0°C and 1 atm 0.1785 g/L density of hquid hehum at its boihng point 0.16 g/mL liquefies at -268.93°C sohdifies at -272.2°C (at 26 atm) to a crystalline, transparent and almost invisible sobd having a sharp melting point cannot be solidified at the atmospheric pressure except by lowering temperatures critical temperature -267.96°C critical pressure 2.24 atm critical volume 57cm3/mol very slightly soluble in water solubility in water 0.0285 mg/L (calculated) at 25°C or 0.174 mL/L at NTP insoluble in ethanol. 

Sokolik, I. N., A. V. Andronova, and T. C. Johnson, Complex Refractive Index of Atmospheric Dust Aerosols, Atmos. Environ., 27A, 2495-2502 (1993). 

An approach widely used by atmospheric scientists is to infer the imaginary part of the refractive index k from measurements of the absorption coefficient a of particulate samples. Diffuse reflection, the photoacoustic effect, and integrating plates have been used for determining absorption even in the presence of considerable scattering these methods are discussed briefly in the following section. The relation (2.52) between a and k, a - 4nk/, is, of course, strictly valid only for homogeneous media. But under some circum-... 

Because the single-scattering albedo depends sensitively on the imaginary part of the refractive index there has been keen interest in determining optical constants of atmospheric particles. These are used to calculate the important parameters in the heat balance problem for present and predicted aerosol... 

Figure 14.1 Imaginary part of the refractive index of several solids and liquids that are found as atmospheric particles.

Lindberg, J. D., and J. B. Gillespie, 1977. Relationship between particle size and imaginary refractive index in atmospheric dust, Appl. Opt., 16, 2628-2630. 

Reagan, J. A., D. M. Byrne, M. D. King, J. D. Spinhime, and B. M. Herman, 1980. Determination of the complex refractive index of atmospheric particulates from bistatic-monostatic lidar and solar radiometer measurements, J. Geophys. Res., 85, 1591-1599. 

Volz, F. E., 1972. Infrared refractive index of atmospheric aerosol substance, Appl. Opt., 11, 755-759. 

Ward, G., K. M. Cushing, R. D. McPeters, and A. E. S. Green, 1973. Atmospheric aerosol index of refraction and size-altitude distribution from bistatic laser scattering and solar aureole measurements, Appl. Opt., 12, 2582-2592. 

---