научный журнал по физике Оптика и спектроскопия ISSN: 0030-4034

DOOGLAV A.V., GAINOV R.R., GOLOVANEVSKIY V.A., KLEKOVKINA V.V., PEN'KOV I.N., VAGIZOV F.G. — 2014 г.

The ground state band structure, magnetic moments, charges and population numbers of electronic shells of Cu and Fe atoms have been calculated for chalcopyrite CuFeS2 using density functional theory. The comparison between our calculation results and experimental data (X-ray photoemission, X-ray absorption and neutron diffraction spectroscopy) has been made. Our calculations predict a formal oxidation state for chalcopyrite as Cu1+Fe3+S . However, the assignment of formal valence state to transition metal atoms appears to be oversimplified. It is anticipated that the valence state can be confirmed experimentally by nuclear magnetic and nuclear quadrupole resonance and Mossbauer spectroscopy methods.

KORABLEVA S.L., PAVLOV V.V., RAKHMATULLIN R.M., SEMASHKO V.V. — 2014 г.

The time and spectral dependences of the dielectric permittivity of the LiY1 - xLuxF4 (x = 0, 0.5, and 1) crystals doped with Ce3+ and co-doped with Yb3+ ions under UV laser excitation were studied by the 8-mm microwave resonant technique at room temperature. The obtained photoconductivity spectrum in 240–310 nm spectral range was interpreted as a stepwise photoionization spectrum of the Ce3+ ions due to sequential 4f–5d and 5d–6s transitions. Average lifetimes of free and defect trapped (color centers) charge carriers were estimated.

CAO G., MERTELJ T., MIHAILOVIC D., POGREBNA A., XU Z.A. — 2014 г.

Employing temperature dependent time-resolved optical femtosecond spectroscopy, we investigated the quasiparticle and Eu2+ spin relaxation dynamics in EuFe2As2 (EFA). As previously reported in other undoped iron-based pnictides, we observe the quasiparticle relaxation bottleneck due to the charge gap opening in the spin density wave (SDW) state below TSDW = 189 K. Below the Eu2+ antiferromagnetic (AFM) spin ordering temperature, TAFM = 19 K, we observe another slower relaxation component, which we attribute to the Eu2+ AFM order dynamics. The slow dynamics of this component suggests a weak coupling between the Eu2+ spins and the carriers in the Fe-d derived bands.

ALAJERAMI Y.S.M., DAWAUD R. S. E. S., HASHIM S., MHAREB M.H.A., SHARBIRIN A.S., TAMCHEK N. — 2014 г.

The study on the optical properties of alkali borate glasses doped with rare earths is an interesting area of research. Dysporosium doped lithium magnesium borate glasses were prepared by melt-quenching technique with dysporosium concentration varying from 0.3 to 1.0 mol%. Physical and optical properties of Lithium Magnesium Borate doped with different concentration of Dy3+ were observed based on its physical parameters, emission spectra and absorption spectra. Furthermore, the absorption spectra of this study exhibits eight absorption bands with hypersensitive peak at 1260 nm (6H9/2). Moreover, two emitted spectra transitions were also observed at 4F9/2 6H15/2, 4F9/2 6H13/2. Lastly, important physical parameters for each concentration of dopant such as density, ions concentration, polaron radius, inter-nuclear distance, refractive index, oscillator strength and other parameters were determined.

HESSIAN H.A., MOHAMED A.-B. A. — 2014 г.

Numerical simulations and calculation of both the total entropy and the sub-entropies are used to investigate the purity loss in nonlinear interaction of a qubit with coherent field. While, the mutual entropy is used as a measure of the total correlations and the negativity as a measure to the entanglement. We show that the purity and entanglement behave different for standard energy dissipation as compared to an energy preserving phase noise coupling as introduced by Milburn. It is found that a very strong sensitivity of the degradation both total correlation with entanglement to the amount of phase damping and the chosen coupling. In particular for a coherent initial field state the maximum obtainable correlation is strongly reduced even for very weak noise.

AIJUN YANG, HELIN WANG, YAN GENG, ZHONGSHI CHEN — 2014 г.

A reflective fiber temperature sensor based on the optical temperature dependent characteristics of a quantum dots (QDs) thin film is developed by depositing the CdSe/ZnS core/shell quantum dots on the SiO2 glass substrates. As the temperature is changed from 30 to 200°C, the peak wavelengths of PL spectra from the sensing head increase linearly with the temperature, while the peak intensity and the full width at half maximum (FWHM) of PL spectra vary exponentially according to the specific physical law. Using the obtained temperature-dependent peak-wavelength shift, the average resolution of the designed fiber temperature sensor can reach 0.12 nm/°C, while it reaches 0.056 nm/°C according to the FWHM of PL spectrum.

BO LU, FUFEI PANG, LIANXIN LI, NA CHEN, SHUPENG LIU, TINGYUN WANG, YANA SHANG, ZHANGMIN DAI, ZHENYI CHEN — 2014 г.

Optical fiber nanoprobe with gold nanoparticles substrate on the surface was prepared by electrostatic self-assembly technology. Surface-enhanced Raman spectroscopy of the cells was measured using the optical fiber nanoprobe by remote detection method and direct detection method using confocal Raman micro-spectroscopy. The spectrum were analyzed with the detailed chemical components. The remote detection method using the optical fiber nanoprobe could make the probe inserting into the cells or tissue, and that may be helpful for the online SERS measurement of the cells in the biomedical research and diagnosis in the future.

CANPOLAT M., SIRCAN-KUCUKSAYAN A. — 2014 г.

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.

HALDAR A., KNYAZEV YU. V., KUZ'MIN YU. I., LUKOYANOV A.V., SURESH K.G. — 2014 г.

Optical properties of two intermetallic compounds TbNi4Fe and TbNi4Co have been studied employing ellipsometry in a spectral range 0.22 15 m to reveal their characteristic features in comparison with the parent compound TbNi5. The electronic structure of TbNi4Fe and TbNi4Co was calculated within the LSDA + U method (local spin density approximation with Hubbard U-correction). Based on the calculated electronic structure results, the theoretical optical conductivity was calculated and used to interpret experimental conductivity in the range of interband optical absorption.

BAOYU GE, JIE LI, JING WU, RUI WANG, RUIYONG WANG, SHUMIN FAN, YUANZHE XIE, ZHIGANG LI — 2014 г.

The interaction between tetracycline antibiotics and gold nanoparticles was studied. With citrate-coated gold nanoparticles as colorimetric probe, a simple and rapid detection method for doxycycline and oxytetracycline has been developed. This method relies on the distance-dependent optical properties of gold nanoparticles. In weakly acidic buffer medium, doxycycline and oxytetracycline could rapidly induce the aggregation of gold nanoparticles, resulting in red-to-blue (or purple) colour change. The experimental parameters were optimized with regard to pH, the concentration of the gold nanoparticles and the reaction time. Under optimal experimental conditions, the linear range of the colorimetric sensor for doxycycline/oxytetracycline was 0.06–0.66 and 0.59 8.85 g mL-1, respectively. The corresponding limit of detection for doxycycline and oxytetracycline was 0.0086 and 0.0838 g mL-1, respectively. This assay was sensitive, selective, simple and readily used to detect tetracycline antibiotics in food products.

AYCA KARASAKAL, SEVGI TATAR ULU — 2014 г.

A sensitive method was developed for the determination of nateglinide in pure and pharmaceutical preparations. The proposed method is based on the derivatization reaction between nateglinide and 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole in borate buffer of pH 10. Fluorescent intensity of derivative was measured at 537 nm using an excitation wavelength of 464 nm. The described method was validated and the analytical parameters of linearity, limit of detection, limit of quantification, accuracy, precision (intra- and inter-day) and recovery were evaluated. The assay was linear over the concentration range of 50–500 ng/mL. The proposed method was applied to study of nateglinide in pure and pharmaceutical preparations.

ABOELSOAD MONA O., EL-DIDAMONY AKRAM M. — 2014 г.

Four simple, sensitive spectrophotometric and spectroflourimetric methods (A-D) for the determination of veterinary drug enrofloxacin (ENFX) in pharmaceutical formulation have been developed. Method (A) is based on formation of ternary complex of ENFX with Pd(II) in presence of methyl cellulose as surfactant and acetate-HCl buffer pH 4.0. Method (B) is based on the oxidation of ENFX with alkaline potassium permanganate to give a green colored reaction product. The reaction was monitored spectrophotometrically by measuring the absorbance of the reaction product at 604 nm. Method (C) is based on the oxidation of the ENFX by a known excess of potassium permanganate in acid medium and subsequent determination of unreacted oxidant by reacting it with safronine OSFO. Method (D) is based on the chelation of ENFX with Zr(IV) to produce fluorescent chelate. At the optimum reaction conditions, the drug/metal chelate showed excitation maxima at 280 nm and emission maxima at 440 nm. The optimum experimental parameters for the reaction have been studied. The validity of the described procedures was assessed. Statistical analysis of the results has been carried out revealing high accuracy and good precision. The proposed methods were successfully applied for the determination of the selected drug in pharmaceutical preparation with good recoveries. The procedures were accurate, simple and suitable for quality control application.

EL-DIDAMONY A.M., SHEHATA A.M. — 2014 г.

Two simple, rapid and sensitive spectrophotometric methods have been proposed for the assay of bisoprolol fumarate (BSF), propranolol hydrochloride (PRH) and timolol maleate (TIM) either in bulk or in pharmaceutical formulations. The methods are based on the reaction of the selected drugs with methyl orange (MO) and eriochrome black T in acidic buffers, after extracting in dichloromethane and measured quantitatively with maximum absorption at 428 and 518 nm for MO and EBT, respectively. The analytical parameters and their effects on the reported systems are investigated. The extracts are intensely colored and very stable at room temperature. The calibration graphs were linear over the concentration range of 0.8–6.4, 0.4–3.6, 0.8 5.6 g/mL for BSF, PRH, and TIM, respectively with MO and 0.8–6.4, 0.4–3.2 and 0.8 8.0 g/mL for BSF, PRH and TIM, respectively with EBT. The stoichiometry of the complexes was found to be 1 : 1 in all cases. The proposed methods were successfully extended to pharmaceutical preparations. Excipients used as additive in commercial formulations did not interfere in the analysis. The proposed methods can be recommended for quality control and routine analysis where time, cost effectiveness and high specificity of analytical technique are of great importance.

BING HAN, JIE ZHANG, YUANYUAN LIU, ZHIMENG WANG — 2014 г.

A series of Ba3Lu1 - xCex(BO3)3 phosphors with different x value were prepared by a conventional high-temperature solid-state reaction method, and their spectroscopic characteristic were systematically investigated. The excitation and emission spectra indicate Ce3+ can occupy two different Lu lattice sites and shows different luminescence properties. The spectroscopic characteristic of Ce(1) and Ce(2) which include stokes shift and crystal field depression were investigated. The investigation indicates that Ba3Lu(BO3)3 : Ce3 phosphor can have potential application in white-light emitting diodes due to the near-ultraviolet excitation band and blue light emission of Ce(2) in Ba3Lu(BO3)3.

CAURANT D. — 2014 г.

Highly radioactive nuclear waste must be immobilized in very durable matrices such as glasses, glass-ceramics and ceramics in order to avoid their dispersion in the biosphere during their radioactivity decay. In this paper, we present various examples of spectroscopic investigations (optical absorption, Raman, NMR, EPR) performed to study the local structure of different kinds of such matrices used or envisaged to immobilize different kinds of radioactive wastes. A particular attention has been paid on the incorporation and the structural role of rare earths – both as fission products and actinide surrogates – in silicate glasses and glass-ceramics. An example of structural study by EPR of a ceramic (hollandite) irradiated by electrons (to simulate the effect of the ?-irradiation of radioactive cesium) is also presented.

GAO Q., JIANG Y.S., WEN D.H., ZHANG Y.Z. — 2014 г.

The theoretical and experimental investigations on the polarization imagery system of speckle statistical characteristics and speckle removing method are researched. A method to obtain two images encoded by polarization degree with a single measurement process is proposed. A theoretical model for polarization imagery system on Muller matrix is proposed. According to modern charge coupled device (CCD) imaging characteristics, speckles are divided into two kinds, namely small speckle and big speckle. Based on this model, a speckle reduction algorithm based on a dual-tree complex wavelet transform (DTCWT) and block-matching 3D filter (BM3D) is proposed (DTBM3D). Original laser image data transformed by logarithmic compression is decomposed by DTCWT into approximation and detail subbands. Bilateral filtering is applied to the approximation subbands, and a suited BM3D filter is applied to the detail subbands. The despeckling results show that contrast improvement index and edge preserve index outperform those of traditional methods. The researches have important reference value in research of speckle noise level and removing speckle noise.

ATIF M., DANISH ALI S., FAROOQ W.A., MANSOOR ALI S., MUHAMMAD J. — 2014 г.

The effects of laser irradiation on the surface, structure and optical properties of SnO thin films deposited on glass substrates using electron beam evaporation are investigated. The thin film samples are irradiated using fundamental beam at 1064 nm from Q-switched Nd:YAG pulsed laser with different power densities. Structural morphology of the film is investigated using XRD patterns and AFM image. Both XRD pattern and AFM image show increase in grain size of the film with increasing laser power density. Other optical phenomena, photoluminescence emission, transmission, refractive index determination and optical band gaps calculations are also carried out at various laser power densities. Results from all these investigations reveal expansion in grain size of the crystalline SnO thin film with increasing laser power density.

ALAJERAMI Y.S.M., SAEED M.A., SAIDU A., WAGIRAN H. — 2014 г.

Zinc Lithium Borate glasses of different composition were prepared with the aim of using it for thermoluminescence dosimetry. Melt quenching method was adopted in this process. Fourier transform Infrared (FTIR) spectroscopy and UV-vis-NIR spectroscopy techniques were employed to investigate the infrared spectra and energy band gap of different composition of Zinc Lithium Borate glasses. X-ray diffraction analysis was used to confirm the amorphous nature of the glass samples. Glass forming ability and stability of the glass was checked using differential thermal analysis (DTA). Density, molar volume, refractive index parameters have been analyzed in the light of different concentration of the modifier. The active vibrational modes of 1200 1600 cm-1 for B–O stretching of BO3 units, 800 1200 cm-1 for B–O stretching of BO4 units and 400 800 cm-1 for bending vibration of various borate segments were detected. Addition of ZnO to lithium borate shows its influence in converting the dominant BO3 group to BO4 group. BO4 are known for creating complex defects, a situation that established deep and stable traps good for thermoluminescence phenomena. From optical data, direct and indirect energy band gap has been calculated using the data obtained from UV-vis-NIR spectroscopy. Both direct and indirect band gaps decrease with the increase of modifier Li2CO3.

DERELI O., KARAKAS SARIKAYA E. — 2014 г.

Conformational analysis of 5,7-dimethoxycoumarin was performed and two stable conformers were obtained. The difference between the total energies of these conformers was 1.4698 kcal/mol and the difference between the zero point corrected energies was nearly zero. Vibrational frequences of these conformers were calculated by B3LYP method using 6-311++G(d,p) basis sets and compared with experimentally recorded FT-IR and Raman spectra. Vibrational assignments were made by calculated total energy distributions. Time dependent density functional theory calculations were done by the same level of theory in order to investigate low-lying excited state and obtained results were compared with the maximum absorbtion peak value of experimental UV-visible spectrum.

DAVID S., FOUNTOS G., KALYVAS N., KANDARAKIS I., LIAPARINOS P., MICHAIL CH., VALAIS I. — 2014 г.

Single crystal scintilators are used in various radiation detectors applications. The efficiency of the crystal can be determined by the Detector Optical Gain (DOG) defined as the ratio of the emitted optical photon flux over the incident radiation photons flux. A parameter affecting DOG is the intrinsic conversion efficiency (nC) giving the percentage of the X-ray photon power converted to optical photon power. nC is considered a constant value for X-ray energies in the order of keV although a non-proportional behavior has been reported. In this work an analytical model, has been utilized to single crystals scintillators GSO:Ce, LSO:Ce, and LYSO:Ce to examine whether the intrinsic conversion efficiency shows non proportional behavior under X-ray excitation. DOG was theoretically calculated as a function of the incident X-ray spectrum, the X-ray absorption efficiency, the energy of the produced optical photons and the light transmission efficiency. The theoretical DOG values were compared with experimental data obtained by irradiating the crystals with X-rays at tube voltages from 50 to 140 kV and by measuring the light energy flux emitted from the irradiated screen. An initial value for nC (calculated from literature data) was assumed for the X-ray tube voltage of 50 kV. For higher X-ray tube voltages the optical photon propagation phenomena was assumed constant and any deviations between experimental and theoretical data were associated with changes in the intrinsic conversion efficiency. The experimental errors were below 7% for each experimental setup. The behavior of nC values for LSO:Ce and LYSO:Ce were found very similar, i.e. ranging with values from 0.089 at 50 kV to 0.015 at 140 kV, while for GSO:Ce, nC demonstrated a peak at 80 kV.