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a method of a spectral transparency

The technology of realisation of a method of a spectral transparency is connected, as a rule, with use of thermal sources of probing radiation in a combination to scanning spectral devices.

The basic idea of a method consists in definition of a spectrum of particles according to a spectral transparency g * (ν), connected with diffraction.

It is possible, if change of a transparency in the investigated interval of wave numbers ν, the refractivity connected with change m a little or can be separateed from a diffraction strip of decay.

The method of a spectral transparency for soft particles is stated in [158­161].my we name particles soft if their section of dispersion 2K (δ) is defined under formula Van de the Canvas [161]

Basis of a method of a spectral transparency is use of transformation Mellina [162]

The steady decision of a problem by definition of parametres of an aerosol by means of a method of a spectral transparency is possible, if a transparency is defined on all interval of lengths of waves [163]. However in known devices for today measurement of factor of a spectral transparency only on several lengths of waves, or on some site of lengths of waves is realised, that, undoubtedly, reduces accuracy and method possibilities.

Authors of works [164-166] offer the modified method of a spectral transparency in which definition of factor of a spectral transparency in a wide range of lengths of waves and the decision of a return problem of optics of aerosols a parametrization method is offered. Such modernisation of a method allows to define parametres of submicronic and micron aerosols (depending on an applied range of frequencies of probing radiation) with comprehensible accuracy and reliability.

The equation is applied to restoration of the distribution function of particles in the sizes with use of a method of a spectral transparency [167]

Where I (λ) - intensity of the past through a radiation disperse system; I0 (λ) - intensity of probing radiation; Cn - schetnaja concentration of the condensed phase of a disperse system; l - length of an optical path; Q - the factor of efficiency of easing of probing radiation; D - diameter of particles; λ - wave length of probing radiation; m - complex index of refraction of the condensed phase of a disperse system, f (D) - the distribution function of particles in the sizes.

At the problem decision the experimental information on factor of a spectral transparency is used:

52

Then there is a relation

Where - experimentally measured factor of the spectral

Transparences for length of a wave - experimentally measured

Factor of a spectral transparency for wave length λ2. On a following step a method cyclic pokoordinatnogo descent set parametres α and b functions f (D), representing usual scale - distribution

By which the particle size distribution in investigated an aerosol where and is the standardising factor is described and the distribution scale - is calculated from a condition of equality to unit as integral on all diameters of function.

Further the relation of theoretically received factors of a spectral transparency according to the equation (1.32) for lengths of waves λ1и λ2по to the formula pays off

Where the factor of efficiency of easing of probing radiation Q pays off under exact formulas of theory Mi [166].

At a following stage it is defined nesootvetsvtie between theoretical and experimental data for each kind of a particle size distribution, and that kind gets out, is nonviscous for which is minimum.

Then by means of a high-speed video shooting and use of a program complex the optical length of a path of probing radiation in investigated an aerosol (ι) is defined and percentage by weight of a dispersed phase of an aerosol under the formula where ρ - density of substance of particles of an aerosol pays off; D32 - centre obemnoyopoverhnostnyj diameter of particles; 0 average factor of efficiency of easing.

1.6.2.

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A source: Sitnikova Vera Evgenievna. SPECTROSCOPIC STUDYING of STRUCTURE of POLYMERIC DISPERSE SYSTEMS. The dissertation on competition of a scientific degree of a Cand.Chem.Sci. Tver - 2015. 2015

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