Optics and Spectroscopy

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Retrieval of chromophore concentration in a tissue phantom by diffuse reflectance spectroscopy
Optics and Spectroscopy - Tập 117 - Trang 663-669 - 2014
A. Sircan-Kucuksayan, M. Canpolat
This study describes a method for analysis of back reflectance spectroscopic data to estimate the concentration of endogenous or exogenous chromophores of tissue, noninvasively and in real time. In the study, tissue phantoms were prepared using intralipid and two chromophores, indocyanine green and methylene blue. Reduced scattering and absorption coefficients ranges of tissue phantoms were kept in the range of biological tissues. Spectroscopic measurements on the tissue phantoms were carried out using a miniature spectrometer, an optical fiber probe, a halogen tungsten light source and a laptop. Monte Carlo simulations of the experiments were run, and an average optical path lengths of the detected photons were obtained for different absorption and scattering coefficients. The average optical path lengths of the photons were used to estimate concentrations of the chromophores in the tissue phantoms. Scattering and absorption coefficients were estimated with an average error of 4.7 and 5.4%, respectively. The developed method has the potential to be used in diagnosis of pathologic tissues based on the variation of biochemical composition of tissues and in photodynamic therapy to estimate the concentration of photosensitizers.
Quantum-chemical study of effect of conjugation on structure and spectral properties of C105 sensitizing dye
Optics and Spectroscopy - Tập 110 - Trang 393-400 - 2011
G. V. Baryshnikov, B. F. Minaev, V. A. Minaeva
The structure and spectral properties of two organic ruthenium complexes used as sensitizing dyes for solar batteries (well-known N3 dye and its selenophene-conjugated analogue C105 ([Ru(bpy)(bpysef)(COOH)2(NCS)2] (bpy = 2,2′-bipyridine, bpysef = 4,4′-bis(5-hexylselenophene-2-yl)2,2′-bipyridine)) are comparatively studied within the density functional method. It is shown that the conjugation of the bipyridine ligand with selenophene affects the electronic structure of the C105 dye. A multilevel model for interpreting the electronic spectra of dyes is proposed based on the analysis of the shapes of molecular orbitals. The nature of the absorption bands of these ruthenium complexes in the region of 300–800 nm is explained. It is found that, in the polar acetonitrile solvent, these dyes are negatively solvatochromic, which agrees with the current classical views on the effect of the solvent on the shape of electronic absorption spectra of related compounds.
Quasi-Elastic Light Scattering in Congruent Lithium Niobate Crystals
Optics and Spectroscopy - Tập 125 - Trang 22-27 - 2018
A. A. Anikiev, M. F. Umarov
Raman scattering spectra in the frequency range of 5–75 cm–1 in lithium niobate samples with various structural imperfections were obtained. It is shown that the intensity of quasi-elastic light scattering on the wing of the Rayleigh line demonstrates an exponential dependence on the concentration of large-scale defects in the samples. Calibration curves for the intensity of quasi-elastic scattering dependence at low frequencies on the acoustic quality factor are constructed.
Quasi-molecular emission and nonadiabatic transitions: II. Ca(4s4p 1 P, 4s3d 1 D)-He(1s 2, 1 S 0) quasi-molecule
Optics and Spectroscopy - - 2000
E. N. Bichutskaya, A. Z. Devdariani, A. L. Zagrebin
Spectral Luminescent Properties and Nature of Electronically Excited States of Sulfaguanidine in Water
Optics and Spectroscopy - - 2024
O. K. Bazyl, O. N. Tchaikovskaya, V. S. Chaydonova, E. N. Bocharnikova, G. V. Mayer
The absorption and fluorescence spectra of sulfaguanidine, its complexes with hydrogen bonds, and doubly charged cationic forms have been studied experimentally and theoretically. The orbital nature of electronically excited states is established and a theoretical interpretation of the absorption and fluorescence spectra is given. It was shown that the main reason for the anomalously large Stokes shift of fluorescence is the rearrangement of the benzoid structure of the phenyl fragment of sulfaguanidine into a quasi-quinoid one. The influence of the formation of hydrogen bonds and the addition of a proton on the amount of charge transfer between weakly bound fragments of the molecule has been established.
Numerical simulation of nonlinear properties of fullerene-containing one-dimensional photonic crystal
Optics and Spectroscopy - Tập 112 Số 6 - Trang 902-905 - 2012
И. М. Белоусова, А. А. Рыжов
Modeling the influence of technological parameters of manufacturing LiNbO3:Ti directed couplers on their optical properties
Optics and Spectroscopy - Tập 111 - Trang 277-283 - 2011
V. S. Serebryakova, G. B. Deineka
A universal technique for the numerical simulation of channel waveguides and integrated optical splitters on their basis is presented. The method of finite elements using a Hermitian set of B splines is proposed as an algorithm. This method was used to optimize X-type splitters manufactured by titanium diffusion into a lithium niobate crystal. The results of numerical simulation agree well with the experimental data obtained on specially manufactured samples of X splitters.
The influence of synthesis conditions on the stability of tris(8-hydroxyquinoline) aluminum organometallic luminophore
Optics and Spectroscopy - - 2017
А. А. Аккузина, A. V. Khomyakov, Roman Avetisov, Igor Avetissov
Quantum properties of one-atom maser radiation in the presence of thermal photons
Optics and Spectroscopy - Tập 97 Số 6 - Trang 929-935 - 2004
Т. Б. Карлович, S. Ya. Kilin
A multiwavelength low-pressure radiation source based on argon and xenon chlorides
Optics and Spectroscopy - Tập 92 - Trang 690-691 - 2002
A. K. Shuaibov, A. I. Dashchenko, I. V. Shevera
The characteristics of an excimer radiation source pumped by a subnormal dc glow discharge in an Ar/Xe/Cl2 mixture with the source operating in a spectral range of 160–310 nm were studied. The emission intensities of the 175, 236, 258, and 308 nm bands due to the transitions ArCl (B-X), XeCl (D-X), Cl2 (D′-A′), and XeCl (B-X), respectively, were optimized in relation to the pressure, composition, and discharge current of the mixture.
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