Automatic design of illumination systems

The approach for autodesign of optical characteristics of different illumination units such as backlight systems, led arrays and light boxes is considered. Suggested software solution allows finding optimal configuration of lighting scheme for providing necessary distribution of output light. Additional preprocessing phase is introduced in design process, which provides reduction of design iterations and better convergence compared to conventional design methods, utilizing random fluctuations of design parameter between iterations. The results of several designs of different kinds of illumination systems are presented.     

A quasilinear heat equation with a source: Peaking,localization, symmetry exact solutions,asymptotics, structures

A survey is given of results of investigating unbounded solutions (regimes with peaking) of quasilinear parabolic equations of nonlinear heat conduction with a source. Principal attention is devoted to the investigation of the property of localization of regimes with peaking. A group classification of nonlinear equations of this type is carried out, properties of a broad set of invariant (self-similar) solutions are investigated, and special methods of investigating the space-time structure of unbounded solutions are developed.Translated from Itogi Nauki i Tekhniki, Seriya Sovremennye Problemy Matematiki, Noveishie Dostizheniya, Vol. 28, pp. 95–206, 1986.     

Very Singular Solutions for Thin Film Equations with Absorption

The large-time behavior of weak nonnegative and sign changing solutions of the fourth-order thin film equation (TFE-4) with absorption where    n  ∈ (0, 3)   and the absorption exponent  p  belongs to the  subcritical  range is studied. First, the standard free-boundary problem with zero-height, zero contact angle, and zero-flux conditions at the interface and bounded compactly supported initial data is considered. Very singular similarity solutions (VSSs) have the form Here  f  solves the quasi-linear degenerate elliptic equation that becomes an ODE for    N  = 1   or in the radial setting in      . By a combination of analytical, asymptotic, and numerical methods, existence of various branches of similarity profiles  f  parameterized by  p  is established. Secondly, changing sign VSSs of the Cauchy problem are described.
This study is motivated by the detailed VSS results for the second-order porous medium equation with absorption   ( u  ≥ 0)  which have been known since the 1980s.     

Modeling and computer design of liquid crystal display backlight with light polarization film

The article is devoted to elaboration of the model of scattering polarization film like dual brightness enhancement film (DBEF). This model is used for computer design of backlighting system of liquid crystal display (LCD) where light polarization is important. The model elaboration required development of measurement methods and reconstruction of the parameters for the film polarization, development of the accurate computer model of the polarized light scattering on thin surface. The results of design of LCD backlight with polarization film are presented in the article as well. So it was demonstrated that design of backlight devices with DBEF is possible with help of elaborated software.     

Calculation of the strength of reinforced phenolic-foam flexural elements

Recommendations are given for calculating the maximum bending moments in poured phenolic-foam elements reinforced with wood laths, glass-reinforced plastic cables, and resin-saturated paper rods.Leningrad Zonal Scientific-Research and Planning Institute for Standard and Experimental Design of Residential and Public Buildings. Translated from Mekhanika Polimerov, Vol. 5, No. 2, pp. 359–361, March–April, 1969.     

The stability of Mott polarization analyzers

The stability of Mott conventional spherically symmetric and retarding-potential conical polarimeters are compared for the case when the position of the electron beam at their inputs is changed. The primary electron energies are 500 and 1600 eV. When the electron beam is shifted by 0.6 mm, the count rate of the former polarimeter remains unchanged, while for the latter, it changes by ≈7 and ≈18% for the energies 1600 and 500 eV, respectively. This instability may cause errors in measuring the degree of polarization of the electron beam.     

Photoemission of spinpolarized electrons from strained GaAsP

Strained layer GaAs_.95P_.05 photo cathodes are presented, which emit electron beams spinpolarized to a degree of P = 75% typically. Quantum yields around QE = 0.4% are observed routinely. The figure of merit P² × QE = 2.3 × 10^–3 is comparable to that of the best strained layer cathodes reported in literature. The optimum wavelength of irradiating light around 830 nm is in convenient reach of Ti:sapphire lasers or diode lasers respectively. The cathodes are produced using MOCVD-techniques. A GaAs_.55P_.45-GaAs_.85P_.15 superlattice structure prevents the migration of dislocations from the substrate and bottom layers to the strained overlayer. The surface is protected by an arsenic layer so that no chemical cleaning is necessary before installation into vacuum. The source of polarized electrons attached to the Mainz race track microtron MAMI works with such cathodes now. More than 1000 hours beamtime have been performed successfully.