Wyniki wyszukiwania - BazTech

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Własności optyczne oraz struktura molekularna silikonów na bazie para-(thio)phenoxyphenylu oraz para-(thio)phensulfaphenylu

Dośpiał M., Kaczmarzyk T., Matusiak R., Gacek M.

Przetwórstwo Tworzyw

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2015

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T. 21, Nr 3 (165)

224--228

PL

W pracy dokonano teoretycznej analizy własności optycznych oraz struktury molekularnej materiałów opartych na silikonach stosowanych do produkcji implantów w postaci soczewek wewnątrzgałkowych. Badania teoretyczne struktury i właściwości optycznych wykonane zostały w pakiecie ADF w oparciu o półempiryczną metodę DFT bazującą na podejściu Kohn-Shama. Na podstawie przeprowadzonych badań teoretycznych określono parametry struktury badanych polimerów, takie jak: kąty dihedralne oraz odległości miedzyatomowe. Wyznaczone widma absorpcyjne zostały zestawione z rozkładami wrażliwości fotoreceptorów. Na podstawie uzyskanych wyników stwierdzono obecność maksimum absorpcyjnego w zakresie promowania widzialnego dla związku para-(thio)phensulfaphenylu. Obecność takiego maksimum w zakresie światła widzialnego jest niepożądana i może prowadzić do zaburzeń w postrzeganiu barw.

EN

The paper presents a theoretical analysis of the optical properties and molecular structure of the silicone-based materials used for the manufacture of implants in the form of intraocular lenses. Theoretical studies of the structure and optical properties has been made in the ADF package based on semi-empirical method based on DFT Kohn-Sham approach. On the basis of theoretical studies the structure parameters of investigated polymers has been determined, such as: dihedral angles and interatomic distances. Designated absorption spectra were exhibited together with the photoreceptor sensitivity distributions. Obtained results revealed the presence of absorption maximum in the visible wave range for the para-(thio)phensulfaphenyle. The presence of such a maximum is undesirable and may lead to disturbances in the color perception.

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Retinal images in optomechanical eye model with monofocal intraocular lens

Józwik A., Nowak J., Siedlecki D., Zajac M., Zarówny J.

Optica Applicata

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2011

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Vol. 41, nr 3

593--605

EN

Intraocular lens (IOL) is an artificial lens implanted into the eye. It usually replaces the existing crystalline lens, which is clouded over due to a cataract. In order to evaluate the optical performance of different IOLs an optomechanical model of human eye was developed. This model closely reproduces anatomical and optical properties of the average human eye. This makes it possible to measure the optical performance of different types of intraocular lenses and to estimate the influence of their location in eye on quality of vision. Four monofocal intraocular lenses were taken for analysis. The analysis of the quality of retinal images was carried out by means of either qualitative image comparison or physical quantities estimation. The analysis of LSF and MTF shows that the performance of the lenses tested changes slightly with differences in their design and/or material.

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A theoretical model of the human eye based on ultrasound and corneal data

Falhar M., Rehak J.

Optica Applicata

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2009

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Vol. 39, nr 1

195--210

EN

The purpose of this study was to create a theoretical model of the eye based on a comparison of the real spherical equivalent of the eye and the calculated value of the axial refraction. The main contribution of this model is that it enables calculation of the equatorial plane of the lens for accurate assessment of the IOL position for a spherical eye model. The Gullstrand model of the eye was used as the source eye model and this was modified for the purposes of this study. The axial refraction of the final model of the eye was compared with the spherical equivalent. The accuracy of the developed model was statistically confirmed using statistic tests. Individual calculation of the axial refraction using it shows that IOL calculation is possible without any general statistical presumptions. It permits the calculation of variables with an accuracy accepted by inferential statistics. The accuracy of this theoretical eye model however, is limited by extreme values of variables - an extreme value provides a less accurate result.