S. A. Stepanov

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A method of designing a plastic zoom lens with a diffractive-refractive hybrid corrector, comprising one diffractive lens and one refractive lens, is described. The efficiency of this method is demonstrated by designing a compact zoom lens for a mobile phone. This zoom design, incorporating lenses made only of two commercial optical plastics(More)
The possibility and the efficiency of using a single diffractive lens to achromatize and apochromatize micro-objectives with plastic lenses are shown. In addition, recommendations are given on assembling the starting configurations of the objectives and calculating the design parameters required for subsequent optimization. It is also shown that achievable(More)
We present what we believe is a new hybrid objective consisting of a gradient-index optical element that has external flat refracting surfaces and is made of two different inhomogeneous materials separated by a cemented spherical surface. Microstructures of diffractive lenses are placed on the flat external surfaces of the objective. The most surprising(More)
The paper is devoted to the study of the character of structural changes in the thyroid gland in pregnancy and in progeny of rats with deficient or excessive intake of iodine. A stable model of thyroid transformation was developed under the conditions of the changed regimen of iodine intake in pregnancy. Predominantly proliferative changes of the epithelial(More)
The specific features and outcomes of surgical treatment were analyzed in 122 newly detected patients with pulmonary tuberculomas without prior specific therapy. Postoperative complications developed in 4.1% of the patients undergone surgery, recurrent tuberculosis was observed in 1.6%. Early surgical interventions in this group of patients were found to(More)
The role of chronic placental insufficiency in the ontogenetic maturation of fetal thyroid gland was studied in 75 cases. The second trimester of physiologically normal and complicated by premature delivery pregnancies showed correlations between organometric and histiostereometric indices of placenta and thyroid gland. In case of chronic placental(More)