WorldWideScience

Sample records for cl optical investigations

  1. EPR and optical investigation of europium doped Ba12F19Cl5

    International Nuclear Information System (INIS)

    Single crystals of the new host Ba12F19Cl5 doped with Eu2+ were grown and studied by electron paramagnetic resonance (EPR) and luminescence emission spectroscopy. Three different Eu2+ sites were observed. Two of them had orthorhombic point symmetry while the last one was monoclinic. Physico-chemical and symmetry arguments allowed us to establish correspondence between the different Eu2+ centres and the host cation lattice sites. All three centres presented in their ground state important crystal field splitting. The 80 K luminescence emission spectrum consisted of one broad unsymmetrical f-d band peaking at 22 700 cm-1. No 4f-4f transitions of the Eu2+ ion were observed between room temperature and 80 K. (author)

  2. Optical properties of SnCl2 phosphor

    Science.gov (United States)

    Nara, Jun-ichi; Adachi, Sadao

    2011-04-01

    A white SnCl2 phosphor is synthesized by the chemical etching of Sn shots in an aqueous HCl solution. The optical properties of this phosphor are investigated using diffuse reflectance, photoluminescence (PL) analysis, PL excitation spectroscopy, and PL lifetime measurements. The SnCl2 phosphor exhibits PL in the blue (˜460 nm) and red spectral regions (˜600 nm) under ultraviolet excitation (≥4.1 eV). The differences in the PL features observed using Nd:YAG (λ = 266 nm) and He-Cd (λ = 325 nm) lasers as excitation light sources are interpreted using the configurational-coordinate model, taking into account the band-gap energy (˜3.8 eV) of SnCl2 and the excited-state energies of the Sn2+ ions. A reliable energy level diagram for Sn2+ ions in the SnCl2 host is also proposed.

  3. A hydrochemical investigation using 36Cl/Cl in groundwaters

    OpenAIRE

    Metcalfe, R.

    2003-01-01

    This report describes 36Cl studies which were undertaken during the H14 financial year. 6 groundwater samples were collected for 36Cl analysis. The results of this study suggest that 36Cl data could potentially be useful for interpreting groundwater origins and flow paths.

  4. Surface defect free growth of a spin dimer TlCuCl3 compound crystals and investigations on its optical and magnetic properties

    Science.gov (United States)

    Ryu, Gihun; Son, Kwanghyo

    2016-05-01

    A defect-free high quality single crystal of spin dimer TlCuCl3 compound is firstly synthesized at the optimal growth temperature using the vertical Bridgman method. In this study, we clearly found that the cupric chloride is easily decomposed into the Cl- deficient composition at ≥470 °C. The Cl-- related gas phase at the high temperature region also always gives rise to a pinhole-like surface defect at the surface of crystal. Therefore, we clearly verified an exotic anisotropic magnetic behavior (anisotropic ratio of Mb/M(201) at 2 K, 7 T=10) using the defect-free TlCuCl3 crystals in this three-dimensional spin dimer TlCuCl3 compound, relatively stronger magnetic ordering in the H//b than that of H//(201) direction at above the transition magnetic field.

  5. Polychloride monoanions from [Cl3]- to [Cl9]- : a Raman spectroscopic and quantum chemical investigation.

    Science.gov (United States)

    Brückner, Robin; Haller, Heike; Ellwanger, Mathias; Riedel, Sebastian

    2012-04-27

    Polychloride monoanions stabilized by quaternary ammonium salts are investigated using Raman spectroscopy and state-of-the-art quantum-chemical calculations. A regular V-shaped pentachloride is characterized for the [N(Me)(4)][Cl(5)] salt, whereas a hockey-stick-like structure is tentatively assigned for [N(Et)(4)][Cl(2)⋅⋅⋅Cl(3)(-)]. Increasing the size of the cation to the quaternary ammonium salts [NPr(4)](+) and [NBu(4)](+) leads to the formation of the [Cl(3)](-) anion. The latter is found to be a pale yellow liquid at about 40 °C, whereas all the other compounds exist as powders. Further to these observations, the novel [Cl(9)](-) anion is characterized by low-temperature Raman spectroscopy in conjunction with quantum-chemical calculations. PMID:22461376

  6. Optical properties of the Bi+ center in KAlCl4

    International Nuclear Information System (INIS)

    Temperature behavior of the Bi+ center emission, excitation bands and luminescence decay law in KAlCl4 crystal are investigated. Abrupt changes of the monocation optical properties are observed at phase transitions of the host. The observed optical transitions are assigned to the specific energy states of Bi+ ion. It is shown that two thermalized levels are responsible for the luminescence. The experimental temperature behavior of the emission and excitation bands are in agreement with theory of electron–phonon interaction of impurity centers in solids; the effective-phonon frequencies and Huang–Rhys parameters are estimated. The configuration coordinate diagram is determined for the Bi+ center in KAlCl4 crystal. - Highlights: • Optical properties of the Bi+ center in KAlCl4 are investigated in details. • The optical transitions are assigned to the specific energy states of Bi+ ion. • The parameters of electron–phonon interaction of the Bi+ center in KAlCl4 are estimated. • The configuration coordinate diagram of the Bi+ in KAlCl4 is determined

  7. Investigation of the reaction 35Cl(n,γ)36Cl

    International Nuclear Information System (INIS)

    The γ-radiation following capture of non-polarized thermal neutrons in 35Cl has been investigated. Of the 420 γ-rays ascribed to the 35Cl(n,γ)36Cl reaction, 236 have been placed in a 36Cl decay scheme. The branching ratios and the excitation energies (with 0.04-0.9 KeV errors) of 72 bound states have been determined. Spin assignments and spin restrictions or confirmations have been made for a total of 20 levels. The multipole mixing ratios for some primary γ-ray transitions have been determined. There exists a significant correlation between (d,p) stripping strengths and (n,γ) reduced primary transition probabilities for transitions to lsub(n)(d,p) = 0 levels

  8. Electron and electron-phonon effects in quasi-two-dimensional molecular conductor θ-(BETS)4HgBr4(C6H5Cl): optical investigations at 300-15 K

    International Nuclear Information System (INIS)

    One studied the polarized spectra of reflection and spectra of optical transmission of θ-(BETS)4HgBr4(C6H5Cl) quasi-two-dimensional molecular conductor within 700-6500 cm-1 range under 300-15 K temperatures and within 9000-40000 cm-1 under 300 K for two principal directions within crystal plane parallel to conducting layers of BETS molecules. Under 300 K within IR region the spectra are characterized by the intensive essential peculiarities (1200-1400 cm-1) caused by electron-oscillation coupling (EOC). At temperature drop within 180-80 K range one observes in the spectra a Lorentz term with ωt = 2900 cm-1 and three extra bands within 800-1180 cm-1 region caused by EOC. The derived results are indicative of unstable structural distortions along two principal directions in a crystal followed by formation of a charge density comparable wave

  9. Thermodynamic modeling and experimental investigations of the CsCl-CaCl2-PuCl3 system

    International Nuclear Information System (INIS)

    The CsCl-CaCl2-PCl3 ternary diagram was calculated from the known binary diagrams. The various principle features, ternary eutectics and peritectics, were verified experimentally by differential thermal analysis. Also, the phase boundaries lying in the polythermal section between a PuCL3 mole fraction of 0.4 on the CsCl-PuCl3 binary and CaCl2 were determined experimentally in some detail. Because the measurements agree well with the prediction, it is assumed that the calculation together with the experimental verification of some of the points has established the entire ternary phase diagram. In addition, d-spacing data from the X-ray diffraction pattern of the compound CsPu2Cl7 are reported. (orig.)

  10. Electron and electron-phonon effects in quasi-two-dimensional molecular conductor theta-(BETS) sub 4 HgBr sub 4 (C sub 6 H sub 5 Cl): optical investigations at 300-15 K

    CERN Document Server

    Vlasova, R M; Petrov, B V; Semkin, N D; Zhilyaeva, E I; Bogdanova, O A; Lyubovskaya, R N; Graja, A

    2002-01-01

    One studied the polarized spectra of reflection and spectra of optical transmission of theta-(BETS) sub 4 HgBr sub 4 (C sub 6 H sub 5 Cl) quasi-two-dimensional molecular conductor within 700-6500 cm sup - sup 1 range under 300-15 K temperatures and within 9000-40000 cm sup - sup 1 under 300 K for two principal directions within crystal plane parallel to conducting layers of BETS molecules. Under 300 K within IR region the spectra are characterized by the intensive essential peculiarities (1200-1400 cm sup - sup 1) caused by electron-oscillation coupling (EOC). At temperature drop within 180-80 K range one observes in the spectra a Lorentz term with omega sub t = 2900 cm sup - sup 1 and three extra bands within 800-1180 cm sup - sup 1 region caused by EOC. The derived results are indicative of unstable structural distortions along two principal directions in a crystal followed by formation of a charge density comparable wave

  11. Provenance analysis by single-quartz-grain SEM-CL/optical microscopy.

    OpenAIRE

    BERNET, Matthias; Basset, Kari

    2005-01-01

    Matthias Bernet est affilié au LGCA depuis 2006. The integration of panchromatic scanning electron microscopycathodoluminescence (SEM-CL) with optical microscopy analysis on single quartz grains is a new technique to interpret provenance of quartz-rich sediments. The combination of information gained from SEM-CL on textural features and CL response with information from optical microscopy allows distinction of different quartz types much more easily then with conventional microscopy or col...

  12. Imaging investigations of optic gliomas

    International Nuclear Information System (INIS)

    Objective: To evaluate CT and MR imaging findings of optic gliomas and their clinical significance. Methods: CT and MR imaging findings of 20 patients with pathologically confirmed optic gliomas were analyzed retrospectively. The age of the patients ranged from 8 months to 69 years. Ten patients were female and ten were male. CT scanning was performed in 10 patients with contrast scanning in 2, and MR imaging was performed in 19 patients with contrast scanning in 14. Results: Of the 20 cases with optic gliomas, a fusiform thickening of the optic nerve was found on CT and/or MR imaging in 12, a tubular enlarging and kinking of the optic nerve in 5, a dumb-bell mass of the optic nerve in 2, and an ovoid mass in 1. Enlargement of intraorbital and intracanalicular segments of the optic nerve was seen in all 20 cases, simultaneous enlargement of intracranial segment in 15, a simultaneous mass of intraocular segment in 4, a simultaneous mass of optic chiasm in 6, and simultaneous enlargement of optic tract in 2. CT scanning performed in 10 patients showed iso-density mass. Enhancement of enlarged optic nerve was observed on postcontrast CT in two. MR imaging performed in 19 patients displayed a long T1 and long T2 signal intensity mass in 12, a long T1 and identical T2 signal intensity mass in 5, and an isointense mass on T1- and T2- weighted images in 2. After contrast administration in 14 cases, marked enhancement of the mass was seen in 12 cases, and moderate enhancement was demonstrated in 2. Of the 7 patients associated with neurofibromatosis I, four optic gliomas appeared as a specific sign-isointense in the center on both T1- and T2-weighted images , hypointense on T1- and T2-weighted images in the intermediate portion, and long T1 and long T2 signal intensity in peripheral portion. After statistical analysis, MR imaging was superior to CT in demonstrating the tumor involvement of the intracanalicular and intracranial segments of the optic nerve (P<0

  13. Optical absorption spectra of mercury centres in KCl and NaCl

    International Nuclear Information System (INIS)

    Optical absorption spectra of KCl and NaCl monocrystals doped with Hg2Cl2 were recorded at room temperature before and after 60Co #betta#-irradiation and F-light bleaching. It is concluded that gamma irradiation produces all types of Hg centres, that the Hg0 centres grow linearly with time of F-light bleaching, and that F-light bleaching enhances all the bands due to Hg centres

  14. Infrared investigation of the phonon spectrum in the frustrated spin cluster compound FeTe2O5Cl

    International Nuclear Information System (INIS)

    We present our optical investigations on the frustrated spin cluster compound FeTe2O5Cl, which develops a long-range antiferromagnetic order below 10 K. We measure the optical reflectivity from the far-infrared to the ultraviolet with polarized light. We focus our attention on the lattice dynamics by discussing the infrared-active modes. Our findings reveal a polarization dependence of the vibrational modes but which do not seem to be affected by structural anomalies linked to the magnetically ordered state at low temperatures.

  15. The CuCl2/Al2O3 Catalyst Investigated in Interaction with Reagents

    Directory of Open Access Journals (Sweden)

    Giuseppe Leofanti

    2001-11-01

    Full Text Available Alumina supported CuCl2, the basic catalyst for ethylene oxychlorination, has been investigated by UV-Vis spectroscopy, EPR, EXAFS and XANES in a wide range (0.25-9.0 wt% of Cu concentration. We have evidenced that, at low Cu content, the formation of a surface aluminate species takes place. The formation of this surface copper aluminate stops at 0.95 wt% Cu / 100 m2; at higher Cu concentrations excess copper chloride precipitates directly from solution during the drying step forming an highly dispersed CuCl2.H2O, phase, overlapping progressively the surface aluminate. Depletion tests and IR spectroscopy of adsorbed NO have demonstrated that the latter is the only active phase. A complete catalytic cycle has then been performed on CuCl2/Al2O3 catalyst. EPR, XANES and EXAFS, have been used to demonstrate that the ethylene oxychlorination reaction: C2H4 + 2HCl + ½ O2 --> C2H4Cl2 + H2O follows a three steps mechanism: (i reduction of CuCl2 to CuCl (2CuCl2 + C2H4 --> C2H4Cl2 + 2CuCl, (ii oxidation of CuCl to give an oxychloride (2CuCl + ½ O2 --> Cu2OCl2 and (iii closure of the catalytic circle by rechlorination with HCl, restoring the original CuCl2 (Cu2OCl2 + 2HCl --> 2CuCl2 + H2O. Finally, we have shown that time resolved, in situ, spectroscopy is a very promising technique to investigate the interplay between catalyst activity and oxidation state of copper.

  16. Thermoluminescence and optical absorption studies of Z1-centres in NaCl crystals doped with samarium

    International Nuclear Information System (INIS)

    Thermal annealing of X-irradiation induced point defects in samarium doped NaCl crystals is investigated by thermoluminescence and optical absorption methods. The results of the influence of pre-heat treatment and optical bleaching on the glow curves and the production of Z1-centres are discussed. The glow curve of a NaCl crystal containing 1 mol% samarium shows four peaks around 60, 90, 130, and 180 0C (T1, T2, T3, and T4 peaks, respectively). Quenching the crystal from higher temperatures results in the enhancement of the T3 and T4 peaks and suppression of T2 peak. Bleaching of X-irradiated crystal with F-light shows that the T3 peak is enhanced whereas the T1 and T4 peaks get suppressed and the T2 peak is completely suppressed. Optical absorption studies of the crystal before and after F-bleaching shows that the F-band decreases and the decrease is accompanied by a broadening towards longer wavelengths. Annealing studies of the X-irradiated crystal at room temperature show that the T1 and T2 peaks correspond to shallow traps. The T3 peak is attributed to Z1 centres and T4 peak to F-centres. These studies confirm the formation of Z1-centres in samarium doped NaCl crystals and the dependence of glow curves on the state of dispersion of the impurity. (author)

  17. The lone-pairs enhanced birefringence and SHG response: A DFT investigation on M2B5O9Cl (M = Sr, Ba, and Pb)

    International Nuclear Information System (INIS)

    Highlights: • Enhanced birefringence and SHG response of Pb2B5O9Cl comparison with its isostructural M2B5O9Cl. • The enhancement originates from the covalent interaction of Pb and O atoms. • The interaction of Pb–O reduces the bandgap comparison with its isostructural M2B5O9Cl. - Abstract: It is important to investigate the electronic structures and optical properties of the UV NLO compound containing lone-pairs electrons, aiming to make a subtle balance among relative large SHG response, big birefringence and deep bandgap. In this paper, the electronic structures and optical properties of M2B5O9Cl (M = Sr, Ba, and Pb) have been investigated using the DFT method. The results show that the enhanced birefringence and SHG response are found in Pb2B5O9Cl comparison with that of Sr2B5O9Cl and Ba2B5O9Cl. And the enhanced birefringence and SHG response in Pb2B5O9Cl originate from the covalent interaction between the oxygen and lead atoms

  18. Investigation of the electron spin resonance of matrix isolated ClO

    International Nuclear Information System (INIS)

    The matrix isolation of ClO in a CO2 matrix is investigated with the aim of providing a detection method for ClO in the stratosphere. Of main concern is the identification and interpretation of the so far unkown ESR-spectrum of matrixisolated ClO. After trapping of ClO in a CO2 matrix at 10 K a highly anisotropic ESR-spectrum is observed which can be attributed to ClO. The shape and the g-values of the spectrum are characteristic for a 2PIsub(3/2) groundstate. Some minor structure discernible on the spectrum can be related to ClO at different trapping sites. After annealing the sample at T > 45 K, the radical concentration diminishes and the gsub(perpendicular to) peak splits into four peaks which correspond to the hyperfinesplitting of ClO. The values of the g and A tensors are determined by comparing the experimental spectrum with computer simulated spectra. In a simple crystal field model these values are compared with molecular parameters of ClO deduced from gas phase spectra. (orig.)

  19. The investigation of influence of iodine ions on a luminescence of Cd Br2 - Mn Cl2

    International Nuclear Information System (INIS)

    Optical and luminescence properties of the crystal Cd Br2 - Mn Cl2, Cd I2 are investigated in the 85 - 295 K temperature interval. It is found that additional doping Cd Br2 - Mn Cl2 with iodine results in increasing photo- and thermoluminescence efficiencies due to 4 Tlg (4 G) → 6 Alg(6S) electron-phonon transitions in Mn2+ -centers under LGI-21 nitric laser excitation. The additional band at 495 nm attributed to radiative recombination of excitons localized on I- ions is observed in X-ray luminescence spectra of the crystal at 85 K. The nature of activation bands in excitation spectra and the mechanism of the thermally stimulated luminescence are discussed

  20. Investigation of electrochemical reduction of GeO2 to Ge in molten CaCl2-NaCl

    International Nuclear Information System (INIS)

    Electrochemical reduction of solid GeO2 has been investigated in the mixed CaCl2-NaCl melt at 1023 K for developing a more efficient process for preparation of Ge. Cyclic voltammetry and potentiostatic electrolysis were applied to study the GeO2-loaded metallic cavity electrode. In addition, porous GeO2 pellets were reduced by potentiostatic and constant cell voltage electrolysis with a graphite anode, and the electrolysis products were analyzed by powder X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectrometry, focusing on understanding the reduction mechanism and the impact of electrode potential on the product purity. It was found that the reduction of GeO2 to Ge occurred at a potential of about -0.50 V (vs. Ag/Ag+), but generating various calcium germanates simultaneously, whose reduction was a little more difficult and needed a potential more negative than -1.00 V. However, if the cathode potential exceeded -1.60 V, Ca (or Na) - Ge intermetallic compounds might form. These results gave an appropriate potential range between -1.10 and -1.40 V for the production of pure germanium. Rapid electrolysis of GeO2 to pure Ge has been realized at a cell voltage of 2.5 V with a current efficiency of about 92%

  1. Investigations of portable cadmium telluride (CdTe(Cl)) detectors for clinical studies with radioactive indicators

    International Nuclear Information System (INIS)

    The combination of small, portable γ-radiation-sensitive Cadmium Telluride (CdTE(Cl)) crystal detectors and portable solid state data storage memories makes it feasible to extend the measuring period in a number of clinical investigations based on the use of various radioisotopes and external detection. Blood sampling can be avoided in some cases. Continuous ambulatory monitoring of relevant physiological parameters is practicable, e.g. kidney function (GFR), left ventricular ejection fraction, subcutaneous blood flow, muscle blood flow and insulin absorption in diabetic patients. In the present methodological study the applicability of the 133-Xe washout technique to subcutaneous (s.c.) adipose tissue blood flow (SBF) has been investigated and adapted to the use of CdTe(Cl) detectors attached to the skin surface for the measurement of local 133-Xe-disappearance rate constants (k). Physical characterization of CdTe(Cl) detectors as γ-sensitive devices has been performed, and adequate counting sensitivities were found without detector energy-resolution properties. The CdTe(Cl) detectors are therefore suitable for single indicator studies. The measuring geometry of CdTe(Cl) detectors was studied and compared with that of stationary Sodium Iodide (NaI(Tl)) detectors in both phantom and in vivo investigations. The spatial properties of CdTe(Cl) detectors could to some extent be adjusted by pulse height discrimination and lead collimation. When long-term measurements were complicated by for instance physical activity of the patients, the small CdTe(Cl) detectors in general showed equal or better performance than the heavy and voluminous NaI(Tl) detectors. The free movement of the ambulatory patient and the avoidance of cable connections to stationary data-collecting systems gave improved possibilities for measurements of the relevant parameters. From this point of view, portable CdTe(Cl) detectors must be considered an important advance for radioactivity studies in

  2. Optical contrast spectra studies for determining thickness of stage-1 graphene-FeCl3 intercalation compounds

    Science.gov (United States)

    Han, Wen-Peng; Li, Qiao-Qiao; Lu, Yan; Yan, Xu; Zhao, Hui; Long, Yun-Ze

    2016-07-01

    Because of novel features in their structural, electronic, magnetic and optical properties, especially potential applications in nanoelectronics, the few-layer graphene intercalation compounds (FLGICs) have been intensively studied recently. In this work, the dielectric constant of the doped graphene of stage-1 FeCl3-GIC is obtained by fitting the optical contrast spectra. And fully intercalated stage-1 FeCl3-FLGICs were prepared by micromechanical cleavage method from graphite intercalation compounds (GICs) for the first time. Finally, we demonstrated that the thickness of stage-1 FeCl3-GICs by micromechanical cleavage can be determined by optical contrast spectra. This method also can be used to other FLGICs, such as SbCl5-FLGICs and AuCl5-FLGICs, etc.

  3. Electronic structure, elastic anisotropy, thermal conductivity and optical properties of calcium apatite Ca5(PO4)3X (X = F, Cl or Br)

    International Nuclear Information System (INIS)

    Highlights: • The degree of elastic anisotropy is ordered as follows BrA > ClA > FA. • The thermal conductivity in (112¯0) plane is smaller than in (0 0 0 1) plane. • The refractive indexes for FA, ClA and BrA are 1.17, 1.19 and 1.21, respectively. - Abstract: The density-functional theory with the generalized gradient approximation was performed to investigate the structural properties, phase stability, electronic structure, elastic properties, and optical properties of selected Ca5(PO3)4F (FA), Ca5(PO3)4Cl (ClA) and Ca5(PO3)4Br (BrA). Results of formation enthalpies show that FA is regarded as the most stable one in these apatites. The electronic structures including band structure, density of states and Mulliken analysis have been discussed. The predicted elastic moduli results indicate that the degree of elastic anisotropy is ordered as follows BrA > ClA > FA. By using the Clarke’s model and Cahill’s model, the thermal conductivities and the anisotropy in thermal conductivity have also been analyzed. Optic properties results indicate that the refractive indexes n for FA, ClA and BrA are 1.17, 1.19 and 1.21, respectively

  4. Electronic structure, elastic anisotropy, thermal conductivity and optical properties of calcium apatite Ca{sub 5}(PO{sub 4}){sub 3}X (X = F, Cl or Br)

    Energy Technology Data Exchange (ETDEWEB)

    Li, Cheng-Xiu [Kunming University of Science and Technology, Kunming 650093 (China); Institute of Multipurpose Utilization of Mineral Resources, Chinese Academy of Geological Sciences, Chengdu 610041 (China); Research Center of Multipurpose Utilization of Metal Mineral Resources of China Geological Survey, Chengdu 610041 (China); Duan, Yong-Hua, E-mail: duanyh@kmust.edu.cn [Kunming University of Science and Technology, Kunming 650093 (China); Hu, Wen-Cheng [School of Mechanical and Electrical Engineering, Nanchang University, Nanchang 330031 (China)

    2015-01-15

    Highlights: • The degree of elastic anisotropy is ordered as follows BrA > ClA > FA. • The thermal conductivity in (112{sup ¯}0) plane is smaller than in (0 0 0 1) plane. • The refractive indexes for FA, ClA and BrA are 1.17, 1.19 and 1.21, respectively. - Abstract: The density-functional theory with the generalized gradient approximation was performed to investigate the structural properties, phase stability, electronic structure, elastic properties, and optical properties of selected Ca{sub 5}(PO{sub 3}){sub 4}F (FA), Ca{sub 5}(PO{sub 3}){sub 4}Cl (ClA) and Ca{sub 5}(PO{sub 3}){sub 4}Br (BrA). Results of formation enthalpies show that FA is regarded as the most stable one in these apatites. The electronic structures including band structure, density of states and Mulliken analysis have been discussed. The predicted elastic moduli results indicate that the degree of elastic anisotropy is ordered as follows BrA > ClA > FA. By using the Clarke’s model and Cahill’s model, the thermal conductivities and the anisotropy in thermal conductivity have also been analyzed. Optic properties results indicate that the refractive indexes n for FA, ClA and BrA are 1.17, 1.19 and 1.21, respectively.

  5. In-vivo optical investigation of psoriasis

    Science.gov (United States)

    Kapsokalyvas, Dimitrios; Cicchi, Riccardo; Bruscino, Nicola; Alfieri, Domenico; Massi, Daniela; Lotti, Torello; Pavone, Francesco S.

    2011-03-01

    Psoriasis is an autoimmune disease of the skin characterized by hyperkeratosis, hyperproliferation of the epidermis, inflammatory cell accumulation and increased dilatation of dermal papillary blood vessels. Cases of psoriasis were investigated in vivo with optical means in order to evaluate the potential of in vivo optical biopsy. A Polarization Multispectral Dermoscope was employed for the macroscopic observation. Features such as the 'dotted' blood vessels pattern was observed with high contrast. The average size of dot vessels in Psoriasis was measured to be 974 μm2 which is much higher compared to healthy skin. High resolution image sections of the epidermis and the dermis were produced with a custom made Multiphoton Microscope. Imaging extended from the surface of the lesion down to the papillary dermis, at a depth of 200 μm. In the epidermis, a characteristic morphology of the stratum corneum found only in Psoriasis was revealed. Additionally, the cytoplasmic area of the cells in the stratum spinosum layer was found to be smaller than normal. In the dermis the morphological features were more pronounced, where the elongated dermal papillae dominated the papillary layer. Their length exceeds 100μm, which is a far greater value compared to that of healthy skin. These in vivo observations are consistent with the ex vivo histopathological observations, supporting both the applicability and potentiality of multispectral dermoscopy and multiphoton microscopy in the field of in vivo optical investigation and biopsy of skin.

  6. Optical destruction of radiation-induced F- and V-centres in γ-irradiated NaCl and KCl at room temperature

    International Nuclear Information System (INIS)

    The destruction of radiation induced F- and V-centres in γ-irradiated NaCl and KCl, caused by an illumination with F-light at room temperature is investigated in experimental and theoretical aspects. The OH-free NaCl and KCl crystal samples are prepared by irradiation with γ-rays from 60Co-source (dose rate 7800 rad/min) at room temperature. The absorption bands (optical density) of F- and V-centres in both type of samples after optical bleaching by F-light for different periods of time are measured. For comparison the absorption bands of the samples after annealing at 400 deg C for 10 min are presented as well. The absorption coefficients are evaluated as functions of bleaching time. The spectral distribution of the specific photoconductivity for NaCl and KCl corresponding to the initial value of optical bleaching is obtained. A possible mechanism for an explanation of optical destruction of radiation-induced F- and V-centres in NaCl and KCl is proposed and a model is constructed. The theoretical results are in good agreement with the experimental data

  7. Analytical investigation of AlCl[3]/SO[2]Cl[2] catholyte materials for secondary fuze reserve batteries.

    Energy Technology Data Exchange (ETDEWEB)

    Butler, Paul Charles; Rodriguez, Mark Andrew; Segall, Judith M.; Malizia, Louis A., Jr.; Cherry, Brian Ray; Andrews, Nicholas L.; Clark, Nancy H.; Alam, Todd Michael; Ingersoll, David T.; Tallant, David Robert; Simpson, Regina Lynn; Boyle, Timothy J.; Garcia, Manuel Joseph

    2004-05-01

    Exploration of the fundamental chemical behavior of the AlCl{sub 3}/SO{sub 2}Cl{sub 2} catholyte system for the ARDEC Self-Destruct Fuze Reserve Battery Project under accelerated aging conditions was completed using a variety of analytical tools. Four different molecular species were identified in this solution, three of which are major. The relative concentrations of the molecular species formed were found to depend on aging time, initial concentrations, and storage temperature, with each variable affecting the kinetics and thermodynamics of this complex reaction system. We also evaluated the effect of water on the system, and determined that it does not play a role in dictating the observed molecular species present in solution. The first Al-containing species formed was identified as the dimer [Al({mu}-Cl)Cl{sub 2}]{sub 2}, and was found to be in equilibrium with the monomer, AlCl{sub 3}. The second species formed in the reaction scheme was identified by single crystal X-ray diffraction studies as [Cl{sub 2}Al({mu}-O{sub 2}SCl)]{sub 2} (I), a scrambled AlCl{sub 3}{center_dot}SO{sub 2} adduct. The SO{sub 2}(g) present, as well as CL{sub 2}(g), was formed through decomposition of SO{sub 2}CL{sub 2}. The SO{sub 2}(g) generated was readily consumed by AlCl{sub 3} to form the adduct 1 which was experimentally verified when 1 was also isolated from the reaction of SO{sub 2}(g) and AlCl {sub 3}. The third species found was tentatively identified as a compound having the general formula {l_brace}[Al(O)Cl{sub 2}][OSCl{sub 2}]{r_brace}{sub n}. This was based on {sup 27}Al NMR data that revealed a species with tetrahedrally coordinated Al metal centers with increased oxygen coordination and the fact that the precipitate, or gel, that forms over time was shown by Raman spectroscopic studies to possess a component that is consistent with SOCl{sub 2}. The precursor to the precipitate should have similar constituents, thus the assignment of {l_brace}[Al(O)Cl{sub 2}][OSCl{sub 2

  8. Adsorption-induced changes of intramolecular optical transitions: PTCDA/NaCl and PTCDA/KCl.

    Science.gov (United States)

    Hochheim, Manuel; Bredow, Thomas

    2015-09-15

    Structural and optical properties of isolated perylene-3,4,9,10-tetracarboxylic acid dianhydride molecules adsorbed on (100) oriented NaCl and KCl surfaces were studied theoretically to analyze the recently observed red-shift of the optical excitation spectrum after adsorption (Müller et al., Phys. Rev. B, 2011, 83, 241203; Paulheim et al. Phys. Chem. Chem. Phys., 2013, 15, 4906). The ground-state structures were obtained by periodic dispersion-corrected density functional theory (DFT) calculations. For the excited-state calculations, nonperiodic time-dependent DFT methods were applied for a cluster model embedded in point charges. The range-separated hybrid functional CAM-B3LYP was used. Correlation-consistent basis sets were used and the calculated excitation energies were extrapolated to the complete basis set limit. The shift of the first optical excitation energy was analyzed in terms of electronic and geometric contributions. It was found that both the distortion of the molecule due to the interaction with the surface and the electrostatic potential of the surface play an important role. PMID:26152591

  9. Optical properties of KCl:Sn2+ phosphors synthesized from aqueous KCl/SnCl2 solutions

    Science.gov (United States)

    Nara, Jun-ichi; Adachi, Sadao

    2011-12-01

    KCl:Sn2+ phosphors were synthesized from aqueous KCl/SnCl2 solutions. Solvents with a molar ratio of KCl : SnCl2 = 1 : M (M = 0 - 5) were dissolved in de-ionized water. The optical properties of the synthesized phosphors were investigated by photoluminescence (PL) analysis, PL excitation spectroscopy (PLE), and PL lifetime measurements. KCl:Sn2+ phosphor synthesized with M = 0.1 exhibited the strongest PL emission in the green (AT band) and red spectral regions (R band). The phosphors synthesized with M ≥ 1 were composites of various potassium chlorostannates and emitted light in the red spectral region (R band). Annealing the M = 0.1 phosphor in dry N2 resulted in a PL spectrum that was the same as those usually observed in melt-grown KCl:Sn2+ phosphors (i.e., exhibiting only the AT emission band). Annealing also led to a change in the PL decay characteristic from a double exponential curve to a single exponential curve. The AT and R emission bands had nearly the same PLE spectra and were related to the deexcitation of the Sn2+ (5s5p) ions in KCl.

  10. X-ray excited optical luminescence studies on the system Ba (, =F, Cl, Br, I)

    Indian Academy of Sciences (India)

    K Govinda Rajan; A Jestin Lenus

    2005-08-01

    The present paper reports the experimental observations on the x-ray excited optical luminescence (XEOL) along with the afterglow and colour center features found for the barium salts, represented by the formula, Ba, where and are the halides. The system thus consists of four dihalides (BaF2, . . . ,BaI2) and six mixed halides (BaFCl,. . . ,BaBrI). To start with, it was found that on two of the binary halides of barium, BaClI and BaBrI, no literature exists, and so these were prepared for the first time and their crystal structures were determined. An x-ray generator of 3-kW rating was next coupled to a spectrometer via a high throughput fiberoptic sensor for recording the luminescence spectra under x-irradiation. Also presented in this paper are the observations on the Ba compounds in which about 0.1 mole% of Eu2+ was doped, in order to study the efficiency between the prompt luminescence and the photostimulated luminescence in these compounds. The crystal structure varies from fluorite (BaF2), to matlockite (BaF) and finally to orthorhombic (BaCl2, . . .,BaBrI) for these compounds. Hence searching for systematics and empirical relations in the observed XEOL behaviour of these compounds is still a challenging problem.

  11. Infrared investigation of the phonon spectrum in the frustrated spin cluster compound FeTe{sub 2}O{sub 5}Cl

    Energy Technology Data Exchange (ETDEWEB)

    Pfuner, F; Degiorgi, L [Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zuerich (Switzerland); Berger, H; Forro, L [Institut de Physique de la Matiere Complexe (IPMC), EPF Lausanne, CH-1015 Lausanne (Switzerland)

    2009-09-16

    We present our optical investigations on the frustrated spin cluster compound FeTe{sub 2}O{sub 5}Cl, which develops a long-range antiferromagnetic order below 10 K. We measure the optical reflectivity from the far-infrared to the ultraviolet with polarized light. We focus our attention on the lattice dynamics by discussing the infrared-active modes. Our findings reveal a polarization dependence of the vibrational modes but which do not seem to be affected by structural anomalies linked to the magnetically ordered state at low temperatures.

  12. Activation of C-Cl by ground-state aluminum atoms: an EPR and DFT investigation.

    Science.gov (United States)

    Joly, Helen A; Newton, Trevor; Myre, Maxine

    2012-01-01

    The reaction of ground-state Al atoms with dichloromethane (CH(2)Cl(2)) in an adamantane matrix at 77 K yielded two mononuclear Al species. The magnetic parameters, extracted from the axial EPR spectrum of Species A/A' (g(1) = 2.0037, g(2) = g(3) = 2.0030, a(Al,1) = 1307 MHz, a(Al,2) = a(Al,3) = 1273 MHz, a(35Cl) = 34 MHz and a(37Cl) = 28 MHz) were assigned to the Al-atom insertion product, ClCH(2)AlCl. Density functional theory (DFT) calculations of the values of the Al and Cl hyperfine interaction (hfi) of the Cl(1)-Cl(2)gauche conformer were in close agreement with the experimental values of ClCH(2)AlCl. The second species, B/B', had identical magnetic parameters to those of ClCH(2)AlCl with the exception that the Al hfi was 15% smaller. Coordination of a ligand, possessing a lone pair of electrons, to the Al atom of the insertion product, [ClCH(2)AlCl]:X, could cause the a(Al) to decrease by 15%. Alternatively, it is possible that the Cl(1)-Cl(2) anti conformer of ClCH(2)AlCl is also isolated in the matrix. Support for the spectral assignments is given by calculation of the nuclear hfi of [ClCH(2)AlCl]:H(2)O and the Cl(1)-Cl(2) anti conformer of ClCH(2)AlCl using a DFT method. The potential energy hypersurface for an Al atom approaching CH(2)Cl(2), calculated at the B3LYP level, suggests that Al atom abstraction of Cl forming AlCl and CH(2)Cl is favoured in the gas phase. When produced in a matrix, the close proximity of AlCl and CH(2)Cl could account for the formation of ClCH(2)AlCl. EPR evidence was also found for the formation of the CHCl(2) radical. PMID:22086441

  13. Structural and optical properties of a NaCl single crystal doped with CuO nanocrystals

    International Nuclear Information System (INIS)

    A cupric oxide (CuO) nanocrystal-doped NaCl single crystal and a pure NaCl single crystal are grown by using the Czochralski (Cz) method. A number of techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, optical absorption in the UV—visible range, and photoluminescence (PL) spectroscopy are used to characterize the obtained NaCl and NaCl:CuO crystals. It is observed that the average radius of CuO crystallites in NaCl:CuO crystal is about 29.87 nm, as derived from the XRD data analysis. Moreover, FT-IR and Raman spectroscopy results confirm the existence of the monoclinic CuO phase in NaCl crystal. UV—visible absorption measurements indicate that the band gap of the NaCl:CuO crystal is 434 nm (2.85 eV), and it shows a significant amount of blue-shift (ΔEg = 1 eV) in the band gap energy of CuO, which is due to the quantum confinement effect exerted by the CuO nanocrystals. The PL spectrum of the NaCl:CuO shows a broad emission band centred at around 438 nm, which is consistent with the absorption measurement. (interdisciplinary physics and related areas of science and technology)

  14. Spectroscopic investigations of Np(V/VI) redox speciation in hyperalkaline TMA-(OH, Cl) solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gaona, X.; Dardenne, K.; Liu, X.; Rothe, J.; Denecke, M.A.; Altmaier, M. [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. fuer Nukleare Entsorgung; Tits, J.; Wieland, E. [Paul Scherrer Institut (PSI), Villigen (Switzerland). Lab. for Waste Management

    2012-07-01

    The redox chemistry of Np(V/VI) was investigated in {proportional_to} 0.6 M tetramethylammonium hydroxide/chloride (TMA-(OH, Cl)) solutions with 9 {<=} -log [H{sup +}] {<=} 13.5. Redox conditions were defined by the absence or presence of ClO{sup -} as oxidizing agent (Na-salt, 5 x 10{sup -3} M and 5 x 10{sup -2} M). The high total Np concentration ([Np]{sub tot} {proportional_to} 2 x 10{sup -3} M) led to the precipitation of solid phases in some of the samples. The carbonate concentration (as impurity of TMA-OH) was 2-3 x 10{sup -3} M. UV-vis/NIR spectra obtained from the supernatant in TMA-(OH, Cl) solutions and absence of ClO{sup -} showed clear Np(V) features, identified as NpO{sub 2}{sup +}, NpO{sub 2}CO{sub 3}{sup -} and (NpO{sub 2}){sub x}(CO{sub 3}){sub y}(OH){sub z}{sup x-2y-z}. No NIR features were observed within 800 nm {<=} {lambda} {<=} 1300 nm for samples with ClO{sup -}. XANES edge energies and features of these samples confirmed the predominance of Np(V) in the absence of ClO{sup -} and Np(VI) in the presence of ClO{sup -}, by comparison to XANES reference spectra of Np(III/IV/V/VI) prepared within the present work by in-situ electrolysis. A similar Np redox distribution was observed for the solid phases based on XANES and EXAFS measurements. EXAFS spectra indicative of Np{sup V}O{sub 2}OH(s) and Np{sup VI}O{sub 3} . xH{sub 2}O(s) were obtained for samples in absence and presence of ClO{sup -}, respectively. The formation of a Na-Np(VI) phase in 5 x 10{sup -2} M ClO{sup -} and -log [H{sup +}] {proportional_to} 12 was also indicated from the EXAFS, chemical analysis and SEM-EDS. These results indicate that Np(VI) aqueous species and solid compounds prevail far below the oxidation border of water in alkaline solutions and also far below the E{sub H} border calculated with the current NEA data selection [1]. These observations are further supported by correlations of literature thermodynamic data for actinides (U, Np, Pu and Am), which predict the

  15. Band structure and optical functions of K2ZnCl4 crystals in ferroelectric phase

    International Nuclear Information System (INIS)

    Band electronic structure (BS), density of states (DOS), and optical functions of K2ZnCl4 crystal for the orthorhombic space group of symmetry Pna21 corresponding to the ferroelectric phase (12 formula units in the crystallographic unit cell) have been calculated for the first time using the density functional theory based code VASP (Vienna Ab-initio Simulation Program). The valence-to-conduction band gap Eg of the crystal is found to be direct in the Γ-point of Brillouin zone. The effective masses m* have been calculated for the top valence and bottom conduction bands for different points and directions of Brillouin zone of the crystal and the results obtained have been analyzed. Peculiarities of the photon energy dependences n(E) and k(E) of refractive (n) and absorption (k) indices obtained in the range 0-28 eV have been identified on the basis of BS and DOS of the crystal. Calculated optical functions agree satisfactorily with the experimental data n(E) in the range of crystal's transparency, E < 5 eV.

  16. CFD Investigation on Free Surface of Immiscible Molten LiCl-KCl/Cd System

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kwangrag; Kim, Sihyung; Shim, Junbo; Park, Seungwoo; Kim, Intae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    LiCl-KCl eutectic serves as an electrolyte, and liquid cadmium serves as a cathode material. Therefore, the electrowinning reactors need to be designed to provide high mass transfer and electrode surface area between the electrode and bulk electrolyte. The efficiency of the electrowinning cell is largely affected by its geometric configuration and electrolyte turbulence. The influence of electrolyte flow on the performance can be evaluated using a CFD model. However, the hydrodynamic behavior in the molten state is not well understood in this system. Therefore, a computational method has been developed to investigate the hydrodynamic behavior of immiscible phases in an electrowinning cell. This paper presents an interface tracking method for modeling the flow of immiscible liquids of LiCl-KCl/Cd in the electrolytic processes. An approach was proposed to provide an insight into the behaviors of free electrode surface in an electrowinning cell. A numerical model has been developed to simulate complex free surface flows in an immiscible molten LiCl-KCl/Cd system. It was found that this method was capable of tracking a contorting free surface as well as interface mass transfer in the multi-phase flow fields. The approach can provide an insight into the behaviors of free electrode surface in an electrowinning cell.

  17. Synthesis, structure and optical properties of two isotypic crystals, Na3MO4Cl (M=W, Mo)

    Science.gov (United States)

    Han, Shujuan; Bai, Chunyan; Zhang, Bingbing; Yang, Zhihua; Pan, Shilie

    2016-05-01

    Two isotypic compounds, Na3MO4Cl (M = W, Mo) have been obtained from the high temperature solution, and their structures were determined by single-crystal X-ray diffraction. Both of them crystallize in the space group P4/nmm of tetragonal system with the unit cells: a=7.5181(15), c=5.360(2) for Na3WO4Cl and a=7.4942(12), c=5.3409(18) for Na3MoO4Cl. The structure exhibits a 3D network built up by the ClNa6 groups, and the MO4 groups reside in the tunnels of the 3D network. The structural similarities and differences between Na3MO4Cl (M=W, Mo) and Sr3MO4F (M=Al, Ga) have been discussed. Meanwhile, detailed structure comparison analyses between Na3MO4Cl (M=W, Mo) and Na3MO4F (M=W, Mo) indicate that the different connection modes of ClNa6 and FNa6 make Na3MO4Cl and Na3MO4F crystallize in different structures. The IR spectra were used to verify the validity of the structure. The diffuse reflectance spectra show that the UV absorption edges are about 249 nm (4.99 eV) and 265 nm (4.69 eV) for Na3WO4Cl and Na3MoO4Cl, respectively. In addition, the first-principles theoretical studies are also carried out to aid the understanding of electronic structures and linear optical properties.

  18. The lone-pairs enhanced birefringence and SHG response: A DFT investigation on M{sub 2}B{sub 5}O{sub 9}Cl (M = Sr, Ba, and Pb)

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Qun [Key Laboratory of Functional Materials and Devices for Special Environments of CAS, Xinjiang Technical Institute of Physics & Chemistry of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Department of Physics, School of Science, Shihezi University, Shihezi 832000 (China); Dong, Xiaoyu [Key Laboratory of Functional Materials and Devices for Special Environments of CAS, Xinjiang Technical Institute of Physics & Chemistry of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011 (China); Engineering Department of Chemistry and Environment, Xinjiang Institute of Engineering, 236 Nanchang Road, Urumqi 830091 (China); Chen, Xinglong [Key Laboratory of Functional Materials and Devices for Special Environments of CAS, Xinjiang Technical Institute of Physics & Chemistry of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yang, Zhihua, E-mail: zhyang@ms.xjb.ac.cn [Key Laboratory of Functional Materials and Devices for Special Environments of CAS, Xinjiang Technical Institute of Physics & Chemistry of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011 (China); Pan, Shilie, E-mail: slpan@ms.xjb.ac.cn [Key Laboratory of Functional Materials and Devices for Special Environments of CAS, Xinjiang Technical Institute of Physics & Chemistry of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011 (China); and others

    2015-05-12

    Highlights: • Enhanced birefringence and SHG response of Pb{sub 2}B{sub 5}O{sub 9}Cl comparison with its isostructural M{sub 2}B{sub 5}O{sub 9}Cl. • The enhancement originates from the covalent interaction of Pb and O atoms. • The interaction of Pb–O reduces the bandgap comparison with its isostructural M{sub 2}B{sub 5}O{sub 9}Cl. - Abstract: It is important to investigate the electronic structures and optical properties of the UV NLO compound containing lone-pairs electrons, aiming to make a subtle balance among relative large SHG response, big birefringence and deep bandgap. In this paper, the electronic structures and optical properties of M{sub 2}B{sub 5}O{sub 9}Cl (M = Sr, Ba, and Pb) have been investigated using the DFT method. The results show that the enhanced birefringence and SHG response are found in Pb{sub 2}B{sub 5}O{sub 9}Cl comparison with that of Sr{sub 2}B{sub 5}O{sub 9}Cl and Ba{sub 2}B{sub 5}O{sub 9}Cl. And the enhanced birefringence and SHG response in Pb{sub 2}B{sub 5}O{sub 9}Cl originate from the covalent interaction between the oxygen and lead atoms.

  19. Esterification of Oleic Acid for Biodiesel Production Catalyzed by SnCl2: A Kinetic Investigation

    Directory of Open Access Journals (Sweden)

    Marcio J. da Silva

    2008-09-01

    Full Text Available The production of biodiesel from low-cost raw materials which generally contain high amounts of free fatty acids (FFAs is a valuable alternative that would make their production costs more competitive than petroleum-derived fuel. Currently, the production of biodiesel from this kind of raw materials comprises a two-stage process, which requires an initial acid-catalyzed esterification of the FFA, followed by a basecatalyzed transesterification of the triglycerides. Commonly, the acid H2SO4 is the catalyst on the first step of this process. It must be said, however, that major drawbacks such as substantial reactor corrosion and the great generation of wastes, including the salts formed due to neutralization of the mineral acid, are negative and virtually unsurmountable aspects of this protocol. In this paper, tin(II chloride dihydrate (SnCl2·2H2O, an inexpensive Lewis acid, was evaluated as catalyst on the ethanolysis of oleic acid, which is the major component of several fat and vegetable oils feedstocks. Tin chloride efficiently promoted the conversion of oleic acid into ethyl oleate in ethanol solution and in soybean oil samples, under mild reaction conditions. The SnCl2 catalyst was shown to be as active as the mineral acid H2SO4. Its use has relevant advantages in comparison to mineral acids catalysts, such as less corrosion of the reactors and as well as avoiding the unnecessary neutralization of products. Herein, the effect of the principal parameters of reaction on the yield and rate of ethyl oleate production has been investigated. Kinetic measurements revealed that the esterification of oleic acid catalyzed by SnCl2·2H2O is first-order in relation to both FFAs and catalyst concentration. Experimentally, it was verified that the energy of activation of the esterification reaction of oleic acid catalyzed by SnCl2 was very close those reported for H2SO4.

  20. Optical and Vibrational Spectra of CsCl-Enriched GeS2-Ga2S3 Glasses.

    Science.gov (United States)

    Klym, Halyna; Karbovnyk, Ivan; Guidi, Mariangela Cestelli; Hotra, Oleksandra; Popov, Anatoli I

    2016-12-01

    Optical and FTIR spectroscopy was employed to study the properties of 80GeS2-20Ga2S3-CsCl chalcohalide glasses with CsCl additives in a temperature range of 77-293 K. It is shown that CsCl content results in the shift of fundamental absorption edge in the visible region. Vibrational bands in FTIR spectra of (80GeS2-20Ga2S3)100 - х (СsCl) x (x = 5, 10, and 15) are identified near 2500 cm(-1), 3700 cm(-1),, around 1580 cm(-1), and a feature at 1100 cm(-1). Low energy shifts of vibrational frequencies in glasses with a higher amount of CsCl can be caused by possible thermal expansion of the lattice and nanovoid agglomeration formed by CsCl additives in the inner structure of the Ge-Ga-S glass. PMID:26956601

  1. C-Cl activation by group IV metal oxides in solid argon matrixes: matrix isolation infrared spectroscopy and theoretical investigations of the reactions of MOx (M = Ti, Zr; x = 1, 2) with CH3Cl.

    Science.gov (United States)

    Zhao, Yanying

    2013-07-11

    Reactions of the ground-state titanium and zirconium monoxide and dioxide molecules with monochloromethane in excess argon matrixes have been investigated in solid argon by infrared absorption spectroscopy and density functional theoretical calculations. The results show that the ground-state MOx (M = Ti, Zr; x = 1, 2) molecules react with CH3Cl to first form the weakly bound MO(CH3Cl) and MO2(CH3Cl) complexes. The MO(CH3Cl) complexes can rearrange to the CH3M(O)Cl isomers with the Cl atom of CH3Cl coordination to the metal center of MO upon UV light irradiation (λ MO + CH3Cl reaction to the more stable CH3M(O)Cl molecules via the MO(CH3Cl) complexes traversing their corresponding transition states. The MO2(CH3Cl) complexes can isomerize to the more stable CH3OM(O)Cl molecules with the addition of the C-Cl bond of CH3Cl to one of the O═M bonds of MO2 upon annealing after broad-band light irradiation. The C-Cl activation by the MOx mechanism was interpreted by the calculated potential energy profiles. PMID:23763350

  2. Optical investigation of nanophotonic lithium niobate-based optical waveguide

    Science.gov (United States)

    Fakhri, Makram A.; Al-Douri, Y.; Hashim, U.; Salim, Evan T.; Prakash, Deo; Verma, K. D.

    2015-10-01

    Lithium niobate (LiNbO3) nanophotonics are prepared on quartz substrate by sol-gel method. They have been deposited with different molarity concentrations and annealed at 500 °C. These samples are characterized and analyzed by scanning electron microscope, atomic force microscopy, X-ray diffraction and ultraviolet-visible. The measured results show an importance of increasing molarity that indicates the structure starts to crystallize to become more regular. The estimated lattice constants, energy gaps and refractive index give good accordance with experimental results. Also, the calculated refractive index and optical dielectric constant are in agreement with experimental data.

  3. Optical coherence tomography investigations of ceramic lumineers

    Science.gov (United States)

    Fernandes, Luana O.; Graça, Natalia D. R. L.; Melo, Luciana S. A.; Silva, Claudio H. V.; Gomes, Anderson S. L.

    2016-02-01

    Lumineers are veneer laminates used as an alternative for aesthetic dental solutions of the highest quality, but the only current means of its performance assessment is visual inspection. The objective of this study was to use the Optical Coherence Tomography (OCT) technique working in spectral domain to analyze in vivo in a single patient, 14 lumineers 180 days after cementation. It was possible to observe images in various kinds of changes in the cementing line and the laminate. It was concluded that the OCT is an effective and promising method to clinical evaluation of the cementing line in lumineers.

  4. Potentiodynamic investigation of A K 12 alloy doped by scandium in the medium of NaCl electrolyte

    International Nuclear Information System (INIS)

    This article is devoted to potentiodynamic investigation of A K 12 alloy doped by scandium in the medium of NaCl electrolyte. Studying of electrochemical corrosion properties of A K 12 alloy doped by scandium showed that scandium additives decrease the corrosion rate of initial alloy. The corrosion-electrochemical properties of A K 12 alloy doped by scandium are studied by means of potentiodynamic method in the medium of 0.03, 0.3, and 3% NaCl solution.

  5. Experimental investigation of 201TlCl-scintigraphy in evaluating therapeutic effect of hyperthermia

    International Nuclear Information System (INIS)

    We investigated the usefulness of 201Tl-scintigraphy in the evaluation of therapeutic effect of hyperthermia. Satoh's experimental lung cancer tumors implanted in the right thighs of donryu rats were treated with hyperthermia using water bath. Tumors were heated at 44degC or 46degC for 15 min. 201Tl-scintigraphy was obtained before, immediately after and 24 hrs after treatment. Counts ratio of the tumor of the normal muscle (T/N ratio) was measured by gamma camera. We examined blood flow of the tumor, and relative tumor growth rate, and performed autoradiogram and histopathological examination of the tumor after 201Tl-scintigraphy. Immediately after hyperthermia, T/N ratio and blood flow of the tumor significantly decreased (p201TlCl in the tumor decreased diffusely. Histopathological finding showed congestion, thrombosis, and swelling of endothelial cells. These results suggest that the decrease in T/N ratio may be caused by the vascular damage due to hyperthermia. The T/N ratio recovered 24 hrs after hyperthermia but was still lower than that for the control. Autoradiogram showed that 201TlCl greatly accumulated in viable tumor tissue but was hardly seen in the necrotic tumor tissue. These results suggest that the decrease in T/N ratio may be caused by increase of necrotic areas. The T/N ratio 24 hrs after hyperthermia correlated (r=0.83) with relative tumor growth rate on 7th day after hyperthermia and, therefore, can be used as an indicator of relative tumor growth rate. 201Tl-scintigraphy can be useful for prediction of therapeutic effect of hyperthermia. (author)

  6. An Investigation of Perceptions of Vietnamese Teachers and Students toward Cooperative Learning (CL)

    Science.gov (United States)

    Thanh, Pham Thi Hong

    2011-01-01

    The present study examined how cooperative learning (CL) is implemented in Vietnamese classrooms, how local teachers' and students' perceived this approach to learning, and what were the local barriers that hindered its implementation. Forty teachers and forty students from twenty Vietnamese colleges completed a questionnaire about CL and…

  7. Optical and microstructural investigations of porous silicon

    Indian Academy of Sciences (India)

    R Prabakaran; R Kesavamoorthy; Alok Singh

    2005-06-01

    Raman scattering and photoluminescence (PL) measurements on (100) oriented -type crystalline silicon (-Si) and porous silicon (PS) samples were carried out. PS samples were prepared by anodic etching of -Si under the illumination of light for different etching times of 30, 60 and 90 min. Raman scattering from the optical phonon in PS showed the redshift of the phonon frequency, broadening and increased asymmetry of the Raman mode on increasing the etching time. Using the phonon confinement model, the average diameter of Si nanocrystallites has been estimated as 2.9, 2.6 and 2.3 nm for 30, 60 and 90 min samples, respectively. Similar size of Si crystallites has been confirmed from the high resolution transmission electron microscopy (HRTEM). Using 2TO phonon mode intensity, we conjectured that the disordered Si region around the pores present in 30 min PS dissolved on etching for 90 min. The photoluminescence (PL) from PS increased in intensity and blue shifted with etching time from 2.1–2.3 eV. Blue shifting of PL is consistent with quantum confinement of electron in Si nanocrystallites and their sizes are estimated as 2.4, 2.3 and 2.1 nm for 30, 60 and 90 min PS, respectively which are smaller than the Raman estimated sizes due to temperature effect. Unambiguous dominance of quantum confinement effect is reported in these PS samples.

  8. Structural, optical and some physical properties of PVDF films filled with LiBr/MnCl2 mixed fillers

    International Nuclear Information System (INIS)

    Films of polyvinylidene fluoride (PVDF) filled with (X)LiBr(20-X)MnCl2 mixture, where X=0, 1, 2, 8, 16 and 20 wt%, were prepared by casting method and studied by ultraviolet/visible optical absorption (UV), differential scanning calorimetry (DSC), X-ray diffraction (XRD), infrared transmission (IR) and electron spin resonance (ESR). The optical absorption spectra suggested the presence of an optical gap (Eg) which depends on filler concentration (W) and arises due to the variation in crystallinity within the polymer matrix. Melting and degradation temperatures were identified using DSC. XRD implied a semicrystalline structure (containing α- and β-PVDF phases for all films). Conjugated double bonds and the role of dimethylformamide with a PVDF chain were detected by IR spectra. The ESR analysis revealed the existence of both isolated and aggregated Mn2+ ions within the PVDF matrix. -- Research highlights: → Films of polyvinylidene fluoride (PVDF) filled with (X)LiBr(20-X)MnCl2 mixture were prepared by casting method. → UV/Vis spectra suggested the presence of an optical gap (Eg), which depends on filler concentration. → Eg arises due to the variation in crystallinity within the polymer matrix. → Melting and degradation temperatures were identified using DSC. → XRD implied a semicrystalline structure (containing α- and β-PVDF phases for all films).

  9. Investigation of Solubility and Phase Equilibria of NaCl – BaCl2 – H2O Triple Water-Salt System at 25oC Temperature by Isothermic Method

    OpenAIRE

    KUL, Ali Rıza; ERGE, Hasan; MEYDAN, İsmet

    2014-01-01

    In the present research, solubility, density, conductivity and phase equilibria of Na2Cl2-BaCl2-H2O triple system existing in Na+, Ba+2/Cl-, (H2PO2)-H2O quadrangular mutual water-salt system were investigated by using physicochemical analysis methods. In the first place, 100 mL distilled water was added into a 100 mL volumetric flask and each time 6-7 g NaCl was added until solubility point of NaCl. Each additionwas followed by mixing two hours and leaving one hour. Having established solubil...

  10. Preparation of AgCl Nano-Crystal Embedded Tellurite Nonlinear Optical Glasses under Electric Field Accompanied Heat Treatment

    Institute of Scientific and Technical Information of China (English)

    Jian LIN; Wenhai HUANG; Bofang LI; Chong JIN; Changcheng LIU; Shuhua LEI; Zhenrong SUN

    2008-01-01

    The quantum effect of nano-crystals is an important factor to improve nonlinear optical performance of nano-crystal embedded glasses,while controlling the size distribution and content of nano-crystals in the glass accurately is a key to obtain good quality.The auxiliary direct current electric field,accompanied with heat treatment,was applied on AgCl containing niobic tellurite glass sheet.The nucleation and crystallization of the glass were well controlled under auxiliary electric field.It was found that the average size of AgCl nano-crystal particles in the glass is smaller than that under single heat treatment,and the content of nano-crystals is higher.Therefore the third-order nonlinear optical performance of the glass was increased a lot.The local-area distributed AgCl nano-crystal particles can also be embedded into a glass sheet by using locally applied electric field.

  11. Structural and optical properties of chemically deposited Cd(S–Se) : CdCl2, Sm films

    Indian Academy of Sciences (India)

    R S Singh; S Bhushan

    2009-04-01

    Results of SEM and XRD studies, optical absorption and photoluminescence (PL) emission spectra and photoconductivity (PC), rise and decay studies are reported for Cd(S–Se) : CdCl2, Sm films prepared by chemical deposition method on glass substrates at 60°C in a water bath. SEM studies show ball-type structures along with voids which are related to layered growth. XRD studies show prominent diffraction lines of CdS and CdSe along with some peaks of CdCl2 and impurity Sm. The values of strain (), grain size () and dislocation density () are evaluated from XRD studies and the nature of crystallinity of the films are discussed. Optical absorption spectra also show the presence of Sm in the lattice. From the results of optical absorption spectra, the band gaps are determined. PL emission spectra of Cd(S–Se) consist of two peaks which are related to the edge emission of CdS and CdSe involving excitons. In Sm-doped emissions corresponding to transitions ${}^{4}G_{5/2}$ to ${}^{6}H_{5/2}$, ${}^{6}H_{7/2}$ and ${}^{6}H_{9/2}$ are observed. Sufficiently high photo current (pc) to dark current (dc) ratios with a maximum value of the order of 106 are also obtained in some special cases. This high photosensitization is related to increase in mobility and life time of carriers due to photo excitation.

  12. Experimental Investigation of Integrated Optical Intensive Impulse Electric Field Sensors

    International Nuclear Information System (INIS)

    We design and fabricate an integrated optical electric field sensor with segmented electrode for intensive impulse electric field measurement. The integrated optical sensor is based on a Mach–Zehnder interferometer with segmented electrodes. The output/input character of the sensing system is analysed and measured. The maximal detectable electric field range (−75 kV/m to 245 kV/m) is obtained by analysing the results. As a result, the integrated optics electric field sensing system is suitable for transient intensive electric field measurement investigation

  13. Experimental Investigation of Integrated Optical Intensive Impulse Electric Field Sensors

    Institute of Scientific and Technical Information of China (English)

    SUN Bao; CHEN Fu-Shen

    2009-01-01

    We design and fabricate an integrated optical electric field sensor with segmented electrode for intensive im-pulse electric field measurement. The integrated optical sensor is based on a Mach-Zehnder interferometer with segmented electrodes. The output/input character of the sensing system is analysed and measured. The max-imal detectable electric field range (-75 kV/m to 245 kV/m) is obtained by analysing the results. As a result, the integrated optics electric field sensing system is suitable for transient intensive electric field measurement investigation.

  14. An investigation of surface photovoltaic properties of TiOPc and AlClPc

    International Nuclear Information System (INIS)

    In this study, surface photovoltages of titanyl phthalocyanine (TiOPc) and chloroaluminum phthalocyanine (AlClPc) were explored using surface photovoltage spectrum (SPS) technique and field-induced photovoltage spectrum (FISPS) technique. The experimental results show that in the region of 300-800 nm both the metallophthalocyanines give two surface photovoltage response bands corresponding to Soret-band (300-420 nm) and Q-band (500-800 nm), respectively, with Bethe splitting of Q-band. It was experimentally confirmed that the two bands of TiOPc and AlClPc result from electron transition of the same type, π-π* transition. From the results of FISPS it was inferred that TiOPc has p-type character and AlClPc has n-type character. It is coincided with the result of the optimal phase of SPV response. Also it was found that the generation efficiency of photocarriers for TiOPc was nearly not affected by the alternation of the sign of the external electrical field. It is different from AlClPc. Since the precursor of photogenerated free carrier for TiOPc is known to be of charge-transfer state, this observation should be an indication that the precursor for AlClPc has an other than the charge-transfer state

  15. An investigation of surface photovoltaic properties of TiOPc and AlClPc

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Qinglin; Wang Dejun; Xu Jinjie; Cao Jian; Sun Jingzhi; Wang Mang

    2003-12-20

    In this study, surface photovoltages of titanyl phthalocyanine (TiOPc) and chloroaluminum phthalocyanine (AlClPc) were explored using surface photovoltage spectrum (SPS) technique and field-induced photovoltage spectrum (FISPS) technique. The experimental results show that in the region of 300-800 nm both the metallophthalocyanines give two surface photovoltage response bands corresponding to Soret-band (300-420 nm) and Q-band (500-800 nm), respectively, with Bethe splitting of Q-band. It was experimentally confirmed that the two bands of TiOPc and AlClPc result from electron transition of the same type, {pi}-{pi}* transition. From the results of FISPS it was inferred that TiOPc has p-type character and AlClPc has n-type character. It is coincided with the result of the optimal phase of SPV response. Also it was found that the generation efficiency of photocarriers for TiOPc was nearly not affected by the alternation of the sign of the external electrical field. It is different from AlClPc. Since the precursor of photogenerated free carrier for TiOPc is known to be of charge-transfer state, this observation should be an indication that the precursor for AlClPc has an other than the charge-transfer state.

  16. Field and laboratory investigations on the effects of road salt (NaCl) on stream macroinvertebrate communities

    International Nuclear Information System (INIS)

    Short-term exposure to road salt did not significantly affect stream macro-invertebrate communities. - Field and laboratory experiments were conducted to examine the effects of road salt (NaCl) on stream macroinvertebrates. Field studies investigated leaf litter processing rates and functional feeding group composition at locations upstream and downstream from point source salt inputs in two Michigan, USA streams. Laboratory studies determined the effects of increasing NaCl concentrations on aquatic invertebrate drift, behavior, and survival. Field studies revealed that leaves were processed faster at upstream reference sites than at locations downstream from road salt point source inputs. However, it was sediment loading that resulted in partial or complete burial of leaf packs, that affected invertebrate activity and confounded normal leaf pack colonization. There were no significant differences that could be attributed to road salt between upstream and downstream locations in the diversity and composition of invertebrate functional feeding groups. Laboratory drift and acute exposure studies demonstrated that drift of Gammarus (Amphipoda) may be affected by NaCl at concentrations greater than 5000 mg/l for a 24-h period. This amphipod and two species of limnephilid caddisflies exhibited a dose response to salt treatments with 96-h LC50 values of 7700 and 3526 mg NaCl/l, respectively. Most other invertebrate species and individuals were unaffected by NaCl concentrations up to 10,000 mg/l for 24 and 96 h, respectively

  17. DFT investigation of endohedral boron oxide nanocapsules: Encapsulation of He, Ne, Ar, H, N, and Cl atoms

    International Nuclear Information System (INIS)

    Graphical abstract: Electronic structure and stabilization energy of fullerene shape boron oxide nanocapsules (X-B20O30, X = He, Ne, Ar, H, N, Cl) were calculated at B3LYP/6-31G∗∗ level of theory. Encapsulation of B20O30 by dopant atoms does not change the energy and degeneracy of HOMO with the exception of Cl-B20O30. Highlights: ► Electronic structure and stabilization energy of fullerene shape boron oxide nanocapsules (X-B20O30). ► Encapsulation of He, Ne, Ar, H, N, and Cl atoms. ► Boron oxide buckyball are potential candidate for gas storage. - Abstract: The electronic structure and stabilization energy of spherical and pyramidal shapes of boron oxide nanocapsules (X-B20O30, X = He, Ne, Ar, H, N, Cl) were investigated by long-range and dispersion corrected density functional theory (DFT + Disp) including CAM-B3LYP, B3LYP-D3, ωB97X-D and B2PLYP-D methods. Based on these calculations, the formation of nanocapsules is an exothermic process (except for Cl-B20O30). The spherical boron oxide nanocapsules are mainly stabilized by dispersion, while the stability of pyramidal complexes is mainly due to monomer relaxation energy. The theoretical results obtained in this work show that the boron oxide capsule is a good potential candidate for gas storage.

  18. Theoretical investigation of potential energy surface and bound states for the van der Waals complex Ar–BrCl dimer

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Rui [School of Mathematics and Information Science, North China University of Water Resources and Electric Power, Zhengzhou (China); Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan (China); Li, Song, E-mail: lsong@yangtzeu.edu.cn [School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou (China); Chen, Shan-Jun; Chen, Yan [School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou (China); Zheng, Li-Min [Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan (China)

    2015-09-08

    Highlights: • A two-dimensional potential for Ar–BrCl is constructed at the CCSD(T) level. • The PES is characterized by three minima and two saddle points between them. • Bound state calculations were carried out for the complex. - Abstract: The intermolecular potential energy surface (PES) of the ground electronic state for the Ar–BrCl dimer is constructed at the CCSD(T) level with the aug-cc-pVQZ basis set and mid-bond functions. The PES is characterized by three minima and two saddle points. The global minimum corresponding to a collinear Ar–BrCl configuration, which has been observed experimentally, is located at R = 4.10 Å and θ = 2.5° with a well depth of −285.207 cm{sup −1}. A nearly T-shaped structure and an anti-linear Ar–ClBr geometry is also predicted. The bound state calculations are preformed to study intermolecular vibrational modes, rotational levels and average structures for the complex. Our transition frequencies, spectroscopic constants and average structures for all isotopomers of the collinear isomer agree well with experimental data. We have also provided pure rotational transitional frequencies for both nearly T-shaped and anti-linear isomers. These results are significant for further experimental investigations of the Ar–BrCl dimer.

  19. Magneto-optical investigations of multifilamentary Bi-2223 tapes

    DEFF Research Database (Denmark)

    Koblischka, M.R.; Johansen, T.H.; Larsen, B.H.; Andersen, N.H.; Wu, H.; Skov-Hansen, P.; Bentzon, M.; Vase, P.

    Flux distributions of multifilamentary Bi-2223 tapes with a varying number of filaments (14 to 55 filaments) are investigated by magneto-optic (MO) imaging at various temperatures (10 less than or equal to T less than or equal to 77 K) and in different field orientations (field applied perpendicu......Flux distributions of multifilamentary Bi-2223 tapes with a varying number of filaments (14 to 55 filaments) are investigated by magneto-optic (MO) imaging at various temperatures (10 less than or equal to T less than or equal to 77 K) and in different field orientations (field applied...

  20. The Ca, Cl, Mg, Na, and P mass fractions in benign and malignant giant cell tumors of bone investigated by neutron activation analysis

    International Nuclear Information System (INIS)

    The Ca, Cl, Mg, Na, and P content and Ca/P, Ca/Mg, Ca/Na, Cl/Ca, and Cl/Na ratios in samples of intact bone, benign and malignant giant cell tumor (GCT) of bone were investigated by neutron activation analysis with high resolution spectrometry of short-lived radionuclides. It was found that in GCT tissue the mass fractions of Cl and Na are higher and the mass fraction of Ca and P are lower than in normal bone tissues. Moreover, it was shown that higher Cl/Na mass fraction ratios as well as lower Ca/Cl, Ca/Mg, and Ca/Na mass fraction ratios are typical of the GCT tissue compared to intact bone. Finally, we propose to use the estimation of such parameters as the Cl mass fraction and the Ca/Cl mass fraction ratio as an additional test for differential diagnosis between benign and malignant GCT. (author)

  1. Thermoluminescence and optical absorption studies of Z1-centres in NaCl crystals doped with terbium

    International Nuclear Information System (INIS)

    The formation of Z1-centres in NaCl:Tb single crystals as well as crystals quenched from 550 0C is studied with the help of optical absorption and thermoluminescence (TL) measurements. The glow curve of NaCl:Tb shows four glow peaks around 60, 90, 140, and 190 0C (T1, T2, T3, and T4, respectively). Bleaching of X-irradiated crystals with F-light shows that the T3-peak is enhanced whereas the T1- and T4-peaks get suppressed. Optical absorption studies of the crystal before and after F-bleaching show that the F-band decreases and the decrease is accompanied by the broadening towards the longer wavelengths. Annealing studies of X-irradiated crystals at room temperature show that the T1- and T2-peaks correspond to shallow traps. The T3-peak is attributed to Z1-centres and the T4-peak to F-centres. It is concluded that Kleefstra's model for the Z1-centre is a more probable model. (author)

  2. Scanning probe and optical tweezer investigations of biomolecular interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rigby-Singleton, Shellie

    2002-07-01

    A complex array of intermolecular forces controls the interactions between and within biological molecules. The desire to empirically explore the fundamental forces has led to the development of several biophysical techniques. Of these, the atomic force microscope (AFM) and the optical tweezers have been employed throughout this thesis to monitor the intermolecular forces involved in biomolecular interactions. The AFM is a well-established force sensing technique capable of measuring biomolecular interactions at a single molecule level. However, its versatility has not been extrapolated to the investigation of a drug-enzyme complex. The energy landscape for the force induced dissociation of the DHFR-methotrexate complex was studied. Revealing an energy barrier to dissociation located {approx}0.3 nm from the bound state. Unfortunately, the AFM has a limited range of accessible loading rates and in order to profile the complete energy landscape alternative force sensing instrumentation should be considered, for example the BFP and optical tweezers. Thus, this thesis outlines the development and construction an optical trap capable of measuring intermolecular forces between biomolecules at the single molecule level. To demonstrate the force sensing abilities of the optical set up, proof of principle measurements were performed which investigate the interactions between proteins and polymer surfaces subjected to varying degrees of argon plasma treatment. Complementary data was gained from measurements performed independently by the AFM. Changes in polymer resistance to proteins as a response to changes in polymer surface chemistry were detected utilising both AFM and optical tweezers measurements. Finally, the AFM and optical tweezers were employed as ultrasensitive biosensors. Single molecule investigations of the antibody-antigen interaction between the cardiac troponin I marker and its complementary antibody, reveals the impact therapeutic concentrations of heparin

  3. SQUID and magneto-optic investigations of flux turbulence

    DEFF Research Database (Denmark)

    Koblischka, M.R.; Johansen, T.H.; Baziljevich, M.; Murakami, M.; Wolf, T.

    Instabilities of the critical state ("turbulence") are observed in various high-T-c, single crystals by means of magneto-optic (MO) imaging. Using the same samples as in the MO investigations, we observe for the first time characteristic steps in the magnetic moment measured by means of a SQUID...

  4. Study of electronic structure, charge density, Fermi energy and optical properties of Cs2KTbCl6 and Cs2KEuCl6

    International Nuclear Information System (INIS)

    Through the assist of the full-potential linear augmented plane wave (FPLAPW) method, the calculations of the electronic band structure, density of states, charge density, Fermi energy and regularity dependent dielectric functions of Cs2KTbCl6 and Cs2KEuCl6 are reported. This study shows that the nature of both these compounds is metallic. The generalized gradient approximations (GGA) exchange correlation potential was applied. The densities of states around Fermi level are frequently subjugated by Eu/Tb-f and DOS below Fermi level are subjugated by Eu/Tb-s/d, Cs-s, Cl-s and K-s/p. The value of the DOS at Fermi level N(EF) is 17.02 and 4.86 (states per unit cell per eV) for Cs2KEuCl6 and Cs2KTbCl6. The bare electronic specific heat coefficient, is found to be 2.95 and 0.84 mJ/mol K2 for Cs2KEuCl6 and Cs2KTbCl6, respectively. Three bands crossing the Fermi level along the Γ−A direction of Brillion zone of Cs2KTbCl6 compound and one band crossing along the Γ−A direction of Brillion zone of Cs2KEuCl6 compounds, to form the Fermi surface. There exists a strong hybridization between Tb/Eu-K-p and Cl-s K-s and at −5.0 and −4.0 eV

  5. Computational investigation on tunable optical band gap in armchair polyacenes

    International Nuclear Information System (INIS)

    Polyacenes in their armchair geometry (phenacenes) have recently been found to possess appealing electronic and optical properties with higher chemical stability and comparatively larger band gap as compared to linear polyacenes. They also behave as high-temperature superconductors upon alkali metal doping. Moreover, the optical properties of crystalline picene can be finely tuned by applying external pressure. We investigated the variation of optical gap as a function of altering the interplanar distances between parallel cofacial phenacene dimers. We employed both time-dependent density functional theory and density matrix renormalization group (DMRG) technique to investigate the lowest singlet excitations in phenacene dimer. Our study showed that the lowest singlet excitation in these systems evolved as a function of interplanar separation. The optical excitation energy gap decreases as a function of inverse interplanar separation of the phenacene dimer. The distant dependent variation of optical absorption at the dimer level may be comparable with experimental observation in picene crystal under pressure. DMRG study also demonstrates that besides picene, electronic properties of higher phenacenes can also be tunable by altering interplanar separation

  6. Electrochemical investigation on the redox chemistry of niobium in LiCl-KCl-KF-Na2O melts

    DEFF Research Database (Denmark)

    Gillesberg, Bo; Bjerrum, Niels; Barner, Jens H. Von;

    1997-01-01

    The system LiCl-KCl-KF-1 mole percent K2NbF7 (molar ration F-/Nb = 8) has been investigated in-the temperature range 370 to 725 degrees C by cyclic and square wave voltammetry. In the temperature range from 370 to 520 degrees C Nb(V) was reduced to Nb(III) in two reversible steps: Nb(V) --> Nb(IV...

  7. Characterization of the non-collinear acousto-optical cell based on calomel (Hg2Cl2) crystal and operating within the two-phonon light scattering

    Science.gov (United States)

    Shcherbakov, Alexandre S.; Arellanes, Adan O.

    2016-03-01

    Performances of any system for data processing based on acousto-optical technique are mainly determined by parameters of the acousto-optical cell (AOC) exploited within the schematic arrangement. Here, basic properties of the AOC, involved into a novel processor for precise optical spectrum analysis dedicated to modern astrophysical applications, are considered. Because potential applications of this processor will be focused on investigations in extra-galactic astronomy as well as studies of extra-solar planets, an advanced regime of the non-collinear two-phonon light scattering has been elaborated for spectrum analysis with significantly improved spectral resolution. Under similar uprated requirements, the AOC, based on that specific regime in the calomel (Hg2Cl2) crystal, had been chosen, and its parameters were analyzed theoretically and verified experimentally. Then, the adequate approach to estimating the frequency/spectral bandwidth and spectral resolution had been developed. The bandwidth was calculated and experimentally realized with the additionally involved tilt angle of light incidence, allowing variations for acoustic frequencies. The resolution was characterized taking into account its doubling peculiar to the nonlinear two-phonon mechanism of light scattering. Proof-of-principle experiments were performed with the calomel AOC of 52 mm optical aperture, providing ~94% efficiency in the transmitted light due to the slow-shear acoustic mode of finite amplitude (the acoustic power density ~150 mW/mm2) with the velocity of 0.347×105 cm/s at the radio-wave acoustic frequency ~71 MHz. As a result, we have obtained the spectral resolution <0.235 Å within the spectral bandwidth <290 Å that looks as the best one can mention at the moment in acousto-optics.

  8. Investigation of Fiber Optics Based Phased Locked Diode Lasers

    Science.gov (United States)

    Burke, Paul D.; Gregory, Don A.

    1997-01-01

    Optical power beaming requires a high intensity source and a system to address beam phase and location. A synthetic aperture array of phased locked sources can provide the necessary power levels as well as a means to correct for phase errors. A fiber optic phase modulator with a master oscillator and power amplifier (MOPA) using an injection-locking semiconductor optical amplifier has proven to be effective in correcting phase errors as large as 4pi in an interferometer system. Phase corrections with the piezoelectric fiber stretcher were made from 0 - 10 kHz, with most application oriented corrections requiring only 1 kHz. The amplifier did not lose locked power output while the phase was changed, however its performance was below expectation. Results of this investigation indicate fiber stretchers and amplifiers can be incorporated into a MOPA system to achieve successful earth based power beaming.

  9. An investigation into Voigt wave propagation for optical sensing

    Science.gov (United States)

    Mackay, Tom G.

    2013-09-01

    In the nonsingular case of optical propagation in a linear, homogeneous, anisotropic, dielectric material, two independent plane waves, with orthogonal polarizations and different phase speeds, can propagate in a given direction. However, in certain dissipative biaxial materials there are particular directions along which these two waves coalesce to form a single plane wave. This coalescent Voigt wave represents the singular case. Most conspicuously, the amplitude of Voigt waves are linearly dependent upon propagation direction. A porous nanostructured thin film which supports Voigt wave propagation was investigated, with a view to possible optical sensing applications. The directions along which Voigt waves propagate can be highly sensitive to the refractive index of a fluid which infiltrates this porous material. Indeed, in our theoretical studies sensitivities which compare favourably to those of surface-plasmon-polariton-based optical sensors were found.

  10. Investigation of Fumed Silica/Aqueous NaCl Superdielectric Material

    OpenAIRE

    Natalie Jenkins; Clayton Petty; Jonathan Phillips

    2016-01-01

    A constant current charge/discharge protocol which showed fumed silica filled to the point of incipient wetness with aqueous NaCl solution to have dielectric constants >108 over the full range of dielectric thicknesses of 0.38–3.9 mm and discharge times of 0.25–>100 s was studied, making this material another example of a superdielectric. The dielectric constant was impacted by both frequency and thickness. For time to discharge greater than 10 s the dielectric constant for all thicknes...

  11. Electro-optical properties investigation of a series of hydroxylphenylporphyrins

    Science.gov (United States)

    Shi, Yingyan; Zheng, Wenqi; Li, Ziheng; Wang, Xingqiao; Wang, Dejun; Qiu, Shilun; Li, Xiangqing

    2006-07-01

    A one-step method was used to synthesize five hydroxylphenylporphyrin monomers with different structures [R.G. Little, J. Heterocyclic Chem. 18 (1981) 129]. They were confirmed by means of different spectroscopic analysis methods. The effects of the number and the position of the peripheral hydroxylphenyl groups of the porphyrin ring and solvents on their fluorescence spectra were discussed according to the change of the UV spectra. It was found that the fluorescence intensity was enhanced with an increase in the number of the peripheral hydroxylphenyl groups of the porphyrin ring. It was also found that the fluorescence intensity at 430 nm was very weak for tetrahydroxylphenylporphyrin (TPP) and tetraphenylporphyrin (5). This phenomenon is related to the structural symmetry. The red shift of the fluorescence spectra in polar solvent DMF relative to that in CH 2Cl 2 can be explained on the basis of the effect of solvation. The fluorescence intensity of hydroxylphenylporphyrin 2 in DMF at 430 nm is much stronger than that in CH 2Cl 2. The surface photovoltaic property of TPP and hydroxylphenylporphyrins 1-5 was studied by means of surface photovoltage spectra (SPS) and field induced surface photovoltage spectra (FISPS), which reveals that all the hydroxylphenylporphyrin are P-type semiconductors. The SPV spectral bands of all the hydroxylphenylporphyrins correspond to the π → π* transition. The SPS was similar to the UV-Vis spectra. It has also been found that the stronger the fluorescence intensity is, the weaker the surface photovoltage intensity is. For all the hydroxylphenylporphyrins and TPP, the surface photovoltage (SPV) of TPP is the weakest, that of hydroxylphenylporphyrin 1 is the strongest, then the SPV of the other hydroxylphenylporphyrins are gradually weakened with an increase in the number of the peripheral hydroxylphenyl groups of the porphyrin ring. This result indicates that controlling the number and position of the peripheral hydroxylphenyl

  12. Acoustic and optical investigations of superfluid 3He. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Manninen, A.

    1993-06-15

    The thesis is an experimental survey of properties of rotating and stationary superfluid (3)He. Two techniques, acoustics and optics, were used. Ultrasound, together with NMR, has provided most of the present experimental knowledge about the superfluid phases of (3)He. The author applied acoustics for the first time to study rotating (3)He. The main result was the discovery of a new vortex in (3)He-A when the magnetic field is low. New phenomena were observed in stationary (3)He as well. Most importantly, one of the collective modes, the real squashing (rsq) mode, of (3)He-B could be excited by means of two-phonon absorption. Superfluid (3)He was studied optically for the first time. No one has previously seen (3)He in the superfluid state. The principal achievement was developing techniques which facilitate optical experiments at temperatures below 1 mK, required to study superfluid (3)He. Optical fibers were used to transmit light between room temperature and the cold parts of the cryostat. Before these investigations, photography had not been done below 10 mK. The usefulness of optics as a proble of the superfluid phases of (3)He was demonstrated by studying the macroscopic shape of the free surface of rotating (3)He-B. The classical parabolic meniscus was observed, which is indicative of the equilibrium density of vortices.

  13. Student as an investigator: simulation on optic synergetics

    Science.gov (United States)

    Poizner, Boris N.; Arshinov, Alexey I.; Mudarisov, Renat R.; Starova, Natalyia A.

    1995-10-01

    The authors take over the following tasks: development of fundamental creative styles of student's thinking; study of some morphogenesis phenomena; the mastery of computer technology of investigations on optical synergetics by the students. The authors have elaborated the system of training-investigating problems presented to students. Each student is put into problem situation of an investigator, solving a new problem concerning the optical morphogenesis in a ring four-mirror interferometer, containing nonlinear medium and linear 2D large-scale transformator of the light field (in the feedback circuit). The phase shift distribution in the cross section of the laser beam is described by nonlinear parabolic equation with displaced space argument. The student must study processes of the optical structures generation by means of the simulation. The content of the training-investigating problems foresees various tasks for the student, for instance an explanation of the simulation results, predictions about the structures shape and behavior, test of the student hypothesis, modification of the physical model.

  14. Thermal and optical properties of the ferroelectric (C 3N 2H 5) 5Bi 2Cl 11 crystal

    Science.gov (United States)

    Przesławski, Janusz; Kosturek, Bogusław; Dacko, Sławomir; Jakubas, Ryszard

    2007-06-01

    Thermal (specific heat) and optical (linear birefringence) studies were performed for a new ferroelectric crystal (C 3N 2H 5) 5Bi 2Cl 11. Two phase transitions were confirmed and described. The first-order paraelastic-ferroelastic phase transition at 360 K was studied with a polarizing microscope. The continuous second-order phase transition at 165 K to the ferroelectric phase is described by the Landau model using specific heat and linear birefringence data. The Landau expansion coefficients B and C are of an order of magnitude higher than the closely related ferroelectric crystal; MAPCB — (CH 3NH 3) 5Bi 2Cl 11. Thermal parameters (such as the excess enthalpy ΔH and the excess entropy ΔS) of the continuous transition were estimated and discussed. The 'two-site' model describing the motion of three of the five imidazolium cations, which is proposed from the structural studies, is fully confirmed by the data from the ac-calorimetric measurements.

  15. Investigation of Cl - and SO4 2- anion absorption in natural soils

    Directory of Open Access Journals (Sweden)

    Snežana Nenadović

    2011-06-01

    Full Text Available In this paper, the results of vertical migration of chloride and sulphate anions in soil are presented. The soil was contaminated with NaCl and CuSO4. Anions migration were monitored during one hydrological year (425 days. The first sample was taken after 150 days and afterwards samples were taken every 50 days. Before the profile contamination physical and chemical analyses of soil have been done. The obtained results show that chloride concentration in soil was in the range from 0.67 mg/kg up to 11.92 mg/kg, while sulphate concentration was in the range from 0.65 mg/kg up to 9.79 mg/kg.

  16. Investigation of OpenCL support in the VecGeom geometry package

    CERN Document Server

    Biro, Gabor

    2014-01-01

    High energy physics always needed a significant amount of computational resources, and with the upgrades of the experiments this need is still growing. Though the computational capacity of the hardwares are increasing as well, since the increasing of the clock frequency of the CPUs stopped a few years ago it needs more effort from the sofware side to exploit all the capabilities. The goal of the VecGeom package is to offer a geometry package that can take advantage most of the modern computing technologies. This report describes the benefits and handicaps of the implementation of the OpenCL support in {VecGeom}, bearing in mind that it has to be as generic as possible and it has to fit in the already existing generic templated structure.

  17. Rovibrational States of ClHCl- Isotopomers: a Joint Theoretical and Spectroscopic Investigation

    Science.gov (United States)

    Botschwina, P.; Sebald, P.; Oswald, R.; Kawaguchi, K.

    2012-06-01

    Explicitly correlated coupled cluster theory at the CCSD(T*)-F12b level and two precise spectroscopic constants were used to construct an analytical potential energy function (PEF) for highly anharmonic ClHCl-. From variational calculations with that PEF, a large number of rovibrational energies of different isotopomers were obtained. Theory helped with assignments of lines observed by IR diode laser spectroscopy and enabled to elucidate rather complex and unusual patterns of rovibrational interactions. In addition, transition dipole moments were predicted and analyzed. T. B. Adler, G. Knizia, and H.-J. Werner, J. Chem. Phys. 127, 221106 (2007) G. Knizia, T. B. Adler, and H.-J. Werner, J. Chem. Phys. 130, 054104 (2009). K. Kawaguchi, J. Chem. Phys. 88, 4186 (1988).

  18. Investigation of optic nerve development using neuronal tracing dyes

    Science.gov (United States)

    Lambert, James L.; Borchert, Mark S.

    1994-08-01

    Numerical techniques are described which allow quantitative interpretation of 2D and 3D histological imagery obtained from tissue samples which are stained with the neuronal tracer Fast Blue. The methods illustrated in this investigation are readily extensible to many different types of micro neuro-anatomy, and are particularly well suited for investigating pharmacological or environmental perturbations on neuron development. These techniques were used to quantitatively describe neurological development of the optic nerve in the pigmented rat. This analysis was used to show that most of the significant refinement in the retinotectal map occurs during the second to fourth week of life and with coincident with eye opening.

  19. Comparative investigations of the P-V-T relationship of NaCl at high pressure and temperature

    International Nuclear Information System (INIS)

    Two different potential models of molecular dynamics (MD) simulations have been applied to investigate the pressure-volume-temperature (P-V-T) relationship and lattice parameter of NaCl under high pressure and temperature. The first one is the shell model (SM) potentials in which due to the short-range interaction pairs of ions are moved together as is the case in polarization of a crystal due to the motion of the positive and negative ions, and the second one is the two-body rigid-ion Born-Mayer-Huggins-Fumi-Tosi (BMHFT) potentials with full treatment of long-range Coulomb forces. The P-V relationship at 300 K, T-V relationship at zero pressure, and lattice parameter a, have been obtained and compared with the available experimental data and other theoretical results. Compared with SM potentials, the MD simulation with BMHFT potentials is very successful in reproducing accurately the measured volumes of NaCl. At an extended pressure and temperature ranges, P-V relationship under different isotherms at selected temperatures, T-V relationship under different pressures, and lattice parameter a have also been predicted. The properties of NaCl are summarized in the pressure range 0-30 GPa and the temperature up to 2000 K

  20. Optical lifetime and linewidth studies of the 7F0→5D0 transition in EuCl3·6H2O: A potential material for quantum memory applications

    International Nuclear Information System (INIS)

    The effect of substituting deuterium for hydrogen in EuCl3·6H2O on the lifetime and homogeneous and inhomogeneous linewidths of the 7F0→5D0 transition at below 4 K are investigated. It is observed that the transition lifetime increases from 116μs to 2.6 ms and the homogeneous linewidth decreases from 4.1 kHz to 430 Hz. The sensitivity of the inhomogeneous broadening to the residual hydrogen concentration is estimated to be 91 MHz/atm%. The potential of utilizing this crystal for quantum memory applications is discussed. - Highlights: ► The optical lifetime of EuCl3·6H2O increases 20 times with full deuteration. ► An optical coherence time of 740μs was observed in EuCl3·6D2O. ► High D purity EuCl3·6H2O is a good candidate material for quantum memories.

  1. Investigation of Fumed Silica/Aqueous NaCl Superdielectric Material

    Directory of Open Access Journals (Sweden)

    Natalie Jenkins

    2016-02-01

    Full Text Available A constant current charge/discharge protocol which showed fumed silica filled to the point of incipient wetness with aqueous NaCl solution to have dielectric constants >108 over the full range of dielectric thicknesses of 0.38–3.9 mm and discharge times of 0.25–>100 s was studied, making this material another example of a superdielectric. The dielectric constant was impacted by both frequency and thickness. For time to discharge greater than 10 s the dielectric constant for all thicknesses needed to be fairly constant, always >109, although trending higher with increasing thickness. At shorter discharge times the dielectric constant consistently decreased, with decreasing time to discharge. Hence, it is reasonable to suggest that for time to discharge >10 s the dielectric constant at all thicknesses will be greater than 109. This in turn implies an energy density for a 5 micron thick dielectric layer in the order of 350 J/cm3 for discharge times greater than 10 s.

  2. Experimental and theoretical investigation of semiconductor optical amplifier (SOA)-based all-optical wavelength converters

    Science.gov (United States)

    Dailey, James M.

    evident in the gain. We also discuss our work in optimizing SOA-based all-optical wavelength converters. We compare the use of passive Mach-Zehnder interferometer (AMZI) and Gaussian bandpass filters to optimize the wavelength-converted output eye quality. We conclude that the Gaussian filters provide superior signal quality, but with much lower output power. We also investigate the optimization of an active AMZI through the careful design of the power splitters. We numerically demonstrate significant and robust improvements in eye quality using our design rules, including increases of 21.5 and 4.6 dB in eye extinction and opening.

  3. Theoretical Investigation on the Geometries and Properties of Guanine-BX3 (X = F, Cl) Complex

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Geometries and binding energies were predicted at the B3LYP/6-311+G* level for the guanine-BX3 (X = F, Cl) systems and four isomers with no imaginary frequencies have been obtained for both guanine-BF3 and guanine-BCl3, respectively. Single energy calculations using much larger basis sets (6-311+G(2df,p) and aug-cc-pVDZ were carried out as well. It was found that the most stable isomer of guanine-BF3 is BF3 connected to N3 of guanine with the stabilization energy of -19.93 kcal/mol (BSSE corrected), while that of guanine-BCl3 is BCl3 connected to O10 of guanine having stabilization energy of -15.02 kcal/mol at the same level. The analyses for the combining interaction between BX3 and guanine with the atom-in-molecules theory (AIM) and natural bond orbital (NBO) methods have been performed. The results indicated that all the isomers are formed with σ-p type interactions between guanine and BX3, in which pyridine-type nitrogen or carbonyl oxygen or nitrogen atom of amino group offers its lone pair electrons to the empty p orbital of boron atom and the concomitance of charge transfer from guanine to BX3 has occurred. Still, one or two hydrogen bonds exist in some isomers of guanine-BX3 system and contribute to the stability of complex systems. Frequency analysis suggested that the stretching vibration of BX3 undergoes a red shift in complexes. Guanine-BF3 complex is more stable than guanine-BCl3 although the B-Y (Y=N, O) bond distance in the latter is shorter.

  4. Theoretical Investigations of Optical Origins of Fluorescent Graphene Quantum Dots

    Science.gov (United States)

    Wang, Jingang; Cao, Shuo; Ding, Yong; Ma, Fengcai; Lu, Wengang; Sun, Mengtao

    2016-04-01

    The optical properties of graphene quantum dots (GQDs) were investigated theoretically. We focused on the photoinduced charge transfer and electron-hole coherence of single-layer graphene in the electronic transitions in the visible regions. Surface functionalization with donor or acceptor groups produced a red shift in the absorption spectrum, and electrons and holes were highly delocalized. The recombination of excited, well-separated electron-hole (e–h) pairs can result in enhanced fluorescence. This fluorescence enhancement by surface functionalization occurs because of the decreased symmetry of the graphene resulting from the roughened structure of the surface-functionalized GQDs.

  5. Investigation of sensing properties of microstructured polymer optical fibres

    Science.gov (United States)

    Witt, J.; Steffen, M.; Schukar, M.; Krebber, K.

    2010-04-01

    We investigated sensing properties of single mode poly methyl methacrylate (PMMA) microstructured polymer optical fibres (MPOF) with mechanically imprinted long period gratings (LPG). After preparation of the MPOF end-faces the samples were elongated with silica fibres. These samples were used to measure the influence of strain to the LPG wavelength which showed the viscoelastic nature of PMMA. We also measured the influence of temperature and humidity. The results show that MPOF LPGs are well suited for strain sensing. One MPOF LPG was stitched to a textile. Using this textile we measured a simulated respiratory motion.

  6. Theoretical Investigations of Optical Origins of Fluorescent Graphene Quantum Dots

    Science.gov (United States)

    Wang, Jingang; Cao, Shuo; Ding, Yong; Ma, Fengcai; Lu, Wengang; Sun, Mengtao

    2016-01-01

    The optical properties of graphene quantum dots (GQDs) were investigated theoretically. We focused on the photoinduced charge transfer and electron-hole coherence of single-layer graphene in the electronic transitions in the visible regions. Surface functionalization with donor or acceptor groups produced a red shift in the absorption spectrum, and electrons and holes were highly delocalized. The recombination of excited, well-separated electron-hole (e–h) pairs can result in enhanced fluorescence. This fluorescence enhancement by surface functionalization occurs because of the decreased symmetry of the graphene resulting from the roughened structure of the surface-functionalized GQDs. PMID:27094439

  7. Surface loss rates of H and Cl radicals in an inductively coupled plasma etcher derived from time-resolved electron density and optical emission measurements

    International Nuclear Information System (INIS)

    A study is undertaken of the loss kinetics of H and Cl atoms in an inductively coupled plasma (ICP) reactor used for the etching of III-V semiconductor materials. A time-resolved optical emission spectroscopy technique, also referred to as pulsed induced fluorescence (PIF), has been combined with time-resolved microwave hairpin probe measurements of the electron density in a pulsed Cl2/H2-based discharge for this purpose. The surface loss rate of H, kwH, was measured in H2 plasma and was found to lie in the 125-500 s-1 range (γH surface recombination coefficient of ∼0.006-0.023), depending on the reactor walls conditioning. The PIF technique was then evaluated for the derivation of kwCl, and γCl in Cl2-based plasmas. In contrast to H2 plasma, significant variations in the electron density may occur over the millisecond time scale corresponding to Cl2 dissociation at the rising edge of the plasma pulse. By comparing the temporal evolution of the electron density and the Ar-line intensity curves with 10% of Ar added in the discharge, the authors show that a time-resolved actinometry procedure using Ar as an actinometer is valid at low to moderate ICP powers to estimate the Cl loss rate. They measured a Cl loss rate of ∼125-200 s-1 (0.03≤γCl≤0.06) at 150 W ICP power for a reactor state close to etching conditions. The Cl surface loss rate was also estimated for high ICP power (800 W) following the same procedure, giving a value of ∼130-150 s-1 (γCl∼0.04), which is close to that measured at 150 W ICP power.

  8. Investigation of fiber optic behavior during gamma irradiation

    International Nuclear Information System (INIS)

    Radiation induced effects in glass-rods and fiber optics have been studied to determine parameters affecting the application of these materials in endoscopes operating in severe radiation environments such as the core of a nuclear power plant or the spent fuel element storage pool. Different glass and fiber types have been investigated and various transmission properties found. The radiation induced transmission loss was measured approximately 1 hour after reactor shutdown. Saturation effects in the transmission loss were observed and changes in glass- and fiber-recovery vs time as a function of radiation dose and annealing temperature were investigated. Various glass-rods together with step- and graded-index fibers have been examined. Fused silica glass show a much similar radiation induced transmission-loss than any other glass-rod or fiber type. The data presented allow conclusions on the design and composition of optical fiber endoscopes to be used in severe radiation environments where image transmission is required in the presence of a radiation field. (author)

  9. Optical investigations on the wide bandgap semiconductors diamond and aluminum nitride

    Energy Technology Data Exchange (ETDEWEB)

    Teofilov, Nikolai

    2007-07-01

    In the context of this thesis, new results about optical defects and intrinsic properties of diamond, AlN and AlGaN alloys have been obtained. The main experimental techniques used were low temperature cathodoluminescence and photoluminescence spectroscopy. First, different aspects of intentional and background doping of diamond were discussed. Thus, the most commonly observed green luminescence emission from boron doped HPHT diamonds has been studied by means of temperature dependent CL in a wide temperature range from 10 K to 450 K. One further subject, addressing deep defect nitrogen related luminescence was a study of nitrogen addition in combustion flame grown CVD diamond layers. Two further topics concern intrinsic excitations in diamond, free excitons and electron-hole drops. Several important parameters like the critical density, the critical temperature, and the low-temperature density inside the drops were evaluated. The ground state density of the electron-hole condensate in diamond is about {approx} 42 times larger than that in Si, and the critical temperature takes very high values in the range of 165K.. 173K. Cathodoluminescence investigations on epitaxial wurtzite AlN layers grown on sapphire, SiC, and Si substrates, have shown that although the material is generally of good optical quality, deep level luminescence are still dominating the spectra. Relatively sharp near-band-edge transitions have been observed in all three samples that exhibit significantly reduced line widths for the AlN/sapphire and the AlN/SiC samples. Much broader emission lines in the near band-gap region have been observed for the first time from the AlN sample grown on Si (111) substrate. Temperature dependent CL measurements and numerical line decompositions reveal complicated substructures in the excitonic lines. The temperature dependence of the energy positions and broadening parameters of the transition have been studied and compared with the other materials. Epitaxial Al

  10. Esterification of oleic acid for biodiesel production catalyzed by SnCl{sub 2}: a kinetic investigation

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, A. L.; Gonzaga Neves, S. C.; Silva, M. J. da [Departament of Chemistry, Federal University of Vicosa, Vicosa, Minas Gerais, 36570-000 (Brazil)

    2008-07-01

    The production of biodiesel from low-cost raw materials which generally contain high amounts of free fatty acids (FFAs) is a valuable alternative that would make their production costs more competitive than petroleum-derived fuel. Currently, the production of biodiesel from this kind of raw materials comprises a two-stage process, which requires an initial acid-catalyzed esterification of the FFA, followed by a basecatalyzed transesterification of the triglycerides. Commonly, the acid H{sub 2}SO{sub 4} is the catalyst on the first step of this process. It must be said, however, that major drawbacks such as substantial reactor corrosion and the great generation of wastes, including the salts formed due to neutralization of the mineral acid, are negative and virtually unsurmountable aspects of this protocol. In this paper, tin(II) chloride dihydrate (SnCl{sub 2}{center_dot}2H{sub 2}O), an inexpensive Lewis acid, was evaluated as catalyst on the ethanolysis of oleic acid, which is the major component of several fat and vegetable oils feedstocks. Tin chloride efficiently promoted the conversion of oleic acid into ethyl oleate in ethanol solution and in soybean oil samples, under mild reaction conditions. The SnCl{sub 2} catalyst was shown to be as active as the mineral acid H{sub 2}SO{sub 4}. Its use has relevant advantages in comparison to mineral acids catalysts, such as less corrosion of the reactors and as well as avoiding the unnecessary neutralization of products. Herein, the effect of the principal parameters of reaction on the yield and rate of ethyl oleate production has been investigated. Kinetic measurements revealed that the esterification of oleic acid catalyzed by SnCl{sub 2}{center_dot}2H{sub 2}O is first-order in relation to both FFAs and catalyst concentration. Experimentally, it was verified that the energy of activation of the esterification reaction of oleic acid catalyzed by SnCl{sub 2} was very close to those reported for H{sub 2}SO{sub 4

  11. Investigation of Stable C and Cl Isotope Effects of Trichloroethene and Tetrachloroethylene during Evaporation at Different Temperatures

    Institute of Scientific and Technical Information of China (English)

    Tingting Yu; Yiqun Gan; Aiguo Zhou; Kai Yu; Yunde Liu

    2014-01-01

    There are variations of reported isotope enrichment factors of chlorinated organic contaminants in evaporation processes. Trichloroethene (TCE) and tetrachloroethylene (PCE) were chosen to study carbon and chlorine isotope effects during evaporation at different temperatures. Equilibrium vapor-liquid carbon and chlorine isotope effects experiments were also conducted. In the equilibrium liquid-vapor system, the 13C was enriched but 37Cl was depleted in the vapor phase, being consistent with previous results. For evaporation average carbon isotope enrichment factor εC were +0.28‰± 0.01‰ for TCE and +0.56‰±0.09‰ for PCE at temperature from 20 to 26 ºC. Meanwhile, average chlorine isotope enrichment factor εCl were -1.33‰±0.21‰ for TCE and -1.00‰±0.00‰ for PCE. The results indicate that during evaporation the equilibrium isotope effect attenuates the magnitude of carbon isotope fractionation whereas enhances the chlorine isotope effect. Isotope fractionation during evaporation is determined by both equilibrium and kinetic factors. Chlorine isotope fractionation is influenced by the evaporation rate which is linked to temperature. When using stable isotope to investigate the behavior of chlorinated organic contaminants in groundwater with slow biodegradation rate, the isotope fractionation resulted from evaporation should be taken into consideration. Furthermore, the environment conditions such as temperature are also factors to be considered.

  12. Investigations in silicate glasses. I. Radiation damage. II. Optical nonlinearity

    International Nuclear Information System (INIS)

    The investigation of two poorly understood but technologically important physical properties of silicate glasses and related materials is described. The use of Electron Paramagnetic Resonance to investigate the nature of radiation-induced damage in glasses exposed to a variety of high-energy radiation sources is discussed first. Second, the measurement of the nonlinear index of refraction coefficient in a variety of optical materials related to the design of high-power laser systems is described. The radiation damage investigations rely heavily on the comparison of experimental results for different experimental situations. The comparison of EPR lineshapes, absolute spin densities and power saturation behavior is used to probe a variety of microscopic and macroscopic aspects of radiation damage in glasses. Comparison of radiation damage associated with exposure to gamma rays and fast neutrons (and combinations thereof) are interpreted in terms of the microscopic damage mechanisms which are expected to be associated with the specific radiations. Comparison of radiation damage behavior in different types of glasses is also interpreted in terms of the behavior expected for the specific materials. The body of data which is generated is found to be internally self-consistent and is also generally consistent with the radiation damage behavior expected for specific situations. A new and versatile technique for measuring the nonlinear index of refraction coefficient, n2, in optical materials is described. The technique utilizes a 1 ns pulsed neodymium-glass laser system and time-resolved interferometry to determine the ratio of the coefficient n2 of sample materials to the n2 of CS2. This method avoids some of the complications associated with performing absolute measurements of n2 and allows the use of a relatively simple experimental technique. The measurements determine the nonlinear index ratios of the samples with an accuracy of about +-15 percent

  13. Investigation of electrochemical etch differences in AlGaAs heterostructures using Cl{sub 2} ion beam assisted etching

    Energy Technology Data Exchange (ETDEWEB)

    Anglin, Kevin, E-mail: kevin.r.anglin@gmail.com; Goodhue, William D. [Massachusetts Institute of Technology Lincoln Laboratory, 244 Wood St., Lexington, Massachusetts 02420 and Department of Physics and Applied Physics, University of Massachusetts Lowell, 1 University Ave., Lowell, Massachusetts 01854 (United States); Swint, Reuel B.; Porter, Jeanne [Massachusetts Institute of Technology Lincoln Laboratory, 244 Wood St., Lexington, Massachusetts 02420 (United States)

    2015-03-15

    A deeply etched, anisotropic 45° and 90° mirror technology is developed for Al{sub x}Ga{sub 1−x}As heterostructures using a Cl{sub 2} ion beam assisted etching system. When etching vertically, using a conductive low-erosion Ni mask, electrochemical etch differences between layers with various Al mole fractions caused nonuniform sidewall profiles not seen in semi-insulating GaAs test samples. These variations, based on alloy composition, were found to be negligible when etching at a 45°. A Si{sub 3}N{sub 4}-Ni etch mask is designed in order to electrically isolate charge buildup caused by the incoming Ar{sup +} ion beam to the Ni layer, preventing conduction to the underlying epitaxial layers. This modification produced smoothly etched facets, up to 8 μm in depth, enabling fabrication of substrate–surface-emitting slab-coupled optical waveguide lasers and other optoelectronic devices.

  14. Infrared investigation of the order-disorder phase transitions in (C 5H 5NH) 6Bi 4Cl 18

    Science.gov (United States)

    Jóźków, J.; Jakubas, R.; Baran, J.

    2000-11-01

    Infrared spectra (4000-500 cm -1) of polycrystalline samples of (C 5H 5NH) 6Bi 4Cl 18 were investigated in the temperature range 23-309 K. An assignment of the observed bands at 23 and 309 K is proposed. A temperature dependence study of the frequencies, ν, half-widths, Δ ν1/2 and intensities of some internal bands of organic cations confirm the presence of phase transitions at 122 and 154 K. In the low-temperature phases numerous internal modes show splitting that indicates a distinct change in the motional state of the pyridinium cations. The spectroscopic results are consistent with earlier 1H NMR studies showing that the phase transitions are governed by the in-plane complex motion of the C 5H 5NH + cations.

  15. Nuclear microprobe and optical investigation of sparkling wine bottles

    International Nuclear Information System (INIS)

    Glass bottles, used for sparkling wine, are treated with freon during manufacturing to harden the inside surface. Although this type of treatment normally improves the properties of the glass, in this case the occurrence of 'egg' formations (egg-shaped rough areas) on distinct areas of bottles, as well as yeast sticking to the insides of bottles at specific areas pointed to the possibility of different areas showing different properties in the same bottle. The question was whether the correct gas was used for the treatment, and secondly, whether the process was controlled well enough to obtain the correct properties for the inside of the glass. We present results of an optical microscopy and nuclear microprobe (NMP) investigation

  16. Nuclear microprobe and optical investigation of sparkling wine bottles

    Science.gov (United States)

    Padayachee, J.; Prozesky, V. M.; Pineda, C. A.

    1999-10-01

    Glass bottles, used for sparkling wine, are treated with freon during manufacturing to harden the inside surface. Although this type of treatment normally improves the properties of the glass, in this case the occurrence of "egg" formations (egg-shaped rough areas) on distinct areas of bottles, as well as yeast sticking to the insides of bottles at specific areas pointed to the possibility of different areas showing different properties in the same bottle. The question was whether the correct gas was used for the treatment, and secondly, whether the process was controlled well enough to obtain the correct properties for the inside of the glass. We present results of an optical microscopy and nuclear microprobe (NMP) investigation.

  17. Nuclear microprobe and optical investigation of sparkling wine bottles

    Energy Technology Data Exchange (ETDEWEB)

    Padayachee, J. E-mail: padayachee@nac.ac.za; Prozesky, V.M.; Pineda, C.A

    1999-09-02

    Glass bottles, used for sparkling wine, are treated with freon during manufacturing to harden the inside surface. Although this type of treatment normally improves the properties of the glass, in this case the occurrence of 'egg' formations (egg-shaped rough areas) on distinct areas of bottles, as well as yeast sticking to the insides of bottles at specific areas pointed to the possibility of different areas showing different properties in the same bottle. The question was whether the correct gas was used for the treatment, and secondly, whether the process was controlled well enough to obtain the correct properties for the inside of the glass. We present results of an optical microscopy and nuclear microprobe (NMP) investigation.

  18. Investigation of murine vasodynamics by Fourier domain optical coherence tomography

    Science.gov (United States)

    Meißner, Sven; Müller, Gregor; Walther, Julia; Krüger, Alexander; Cuevas, Maximiliano; Eichhorn, Birgit; Ravens, Ursula; Morawietz, Henning; Koch, Edmund

    2007-07-01

    In vivo imaging of blood vessels obtain useful insights in characterizing the dynamics of vasoconstriction and vasodilation. Fourier domain optical Coherence Tomography (FD-OCT) imaging technique permits in vivo investigation of blood vessels in their anatomical context without preparation traumata by temporal resolved image stacks. OCT is an optical, contact less imaging technique based on Michelson interferometry of short coherent near infrared light. Particularly by the possibility of a contact-less measurement and the high axial resolution up to 10 microns OCT is superior to an investigation by ultra sound measurement. Furthermore we obtain a high time resolution of vessel dynamic measurements with the used Fourier domain OCT-system by a high A-scan rate [1,22kHz]. In this study the model of saphenous artery was chosen for analyzing function and dynamics. The arteria saphena in the mouse is a suitable blood vessel due to the small inner diameter, a sensitive response to vasoactive stimuli and an advantageous anatomically position. Male wild type mice (C57BL/6) at the age of 8 weeks were fed control or high-fat diet for 10 weeks before analyzing the vasodynamics. The blood vessel was stimulated by dermal application of potassium to induce vasoconstriction or Sodium-Nitroprusside (SNP) to induce vasodilation. The morphology of the a. saphena and vein was determined by 3D image stacks. Time series (72 seconds, 300x512 pixel per frame) of cross-sectional images were analysed using semi automatic image processing software. Time course of dynamic parameters of the vessel was measured.

  19. "XA6" octahedra influencing the arrangement of anionic groups and optical properties in inverse-perovskite [B6O10]XA3 (X = Cl, Br; A = alkali metal).

    Science.gov (United States)

    Yang, Zhihua; Lei, Bing-Hua; Yang, Bin; Pan, Shilie

    2016-06-01

    Exploring the effect of microscopic units, which set up the perovsikte framework, is of importance for material design. In this study, a series of borate halides with inverse-perovskite structures [B6O10]XA3 (X = Cl, Br; A = alkali metal) have been studied. It was revealed that the distortion and volume of XA6 octahedra influence the arrangement of anionic groups, which leads to the flexibility of the perovskite-related framework and differences in optical properties. Under the structural control scheme, the structure of Rb3B6O10Cl was predicted. The stability of the predicted structure was confirmed by an ab initio density functional theory-based method. The calculation shows Rb3B6O10Cl has a short UV cutoff edge of less than 200 nm, a moderate birefringence and a large second harmonic generation response. PMID:27211304

  20. Electrodeposition of tungsten from ZnCl2-NaCl-KCl-KF-WO3 melt and investigation on tungsten species in the melt

    International Nuclear Information System (INIS)

    The electrodeposition of tungsten in ZnCl2-NaCl-KCl-KF-WO3 melt at 250 deg. C was further studied to obtain a thicker deposit. In the ordinary electrolysis at 0.08 V vs. Zn(II)/Zn, the current density decreased from 1.2 mA cm-2 to 0.3 mA cm-2 in 6 h. A thickness of the obtained tungsten layer was 2.1 μm and the estimated current efficiency was 93%. A supernatant salt and a bottom salt were sampled after 6 h from the melting and were analyzed by ICP-AES and XRD. It was found that the soluble tungsten species slowly changes to insoluble ones in the melt. The soluble species was suggested to be WO3F- anion. One of the insoluble species was confirmed to be ZnWO4 and the other one was suggested to be K2WO2F4. Electrodeposition was carried out under the same condition as above except for the intermittent addition of WO3 every 2 h. The current density was kept at the initial value and the thickness was 4.2 μm. The intermittent addition of WO3 was confirmed to be effective to obtain a thicker tungsten film.

  1. Fixed partial dentures investigated by optical coherent tomography

    Science.gov (United States)

    Sinescu, Cosmin; Negrutiu, Meda; Todea, Carmen; Hughes, Mike; Tudorache, Florin; Podoleanu, Adrian G.

    2008-02-01

    Fixed partial prostheses as integral ceramics, integral polymers, metal ceramics or metal polymers bridges, are mainly used in the frontal part of the dental arch (especially the integral bridges). They have to satisfy high stress requirements as well as esthetic. The masticatory stress may induce fractures of the bridges. These may be triggered by initial materials defects or by alterations of the technological process. The fractures of these bridges lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. The purpose of this study is to evaluate the capability of en-face optical coherence tomography (OCT) in detection and analysis of possible fractures in several integral fixed partial dentures. The materials used were represented by several fixed partial prostheses, integral ceramics, integral polymers, metal ceramics and metal polymers bridges. In order to discover the defects, scanning was performed from incisal, vestibular, oral and cervical directions material defects such as fractures and pores were investigated using OCT. In conclusion, en-face OCT has proven as a valuable non invasive method to investigate fixed partial prostheses before their insertion in the oral cavity.

  2. Quantum chemical investigation of linear hydrogen bonding in ONCCN···HX (X = F, Cl, Br) dimers

    Science.gov (United States)

    Varadwaj, Pradeep R.

    Linear hydrogen bonding formed between the nitrogen end of cyanogen-N-oxide (ONCCN) and hydrogen halides HX (X = F, Cl, Br) has been observed in their ground ? states. The order of agreement of energetic stabilities between the correlated functionals used in this calculation is: B3LYP bonds in these dimers follows the conventional trend: ONCCN···HF > ONCCN···HCl > ONCCN···HBr in the series, except H-bond lengths and static dipole polarizabilities which are in reverse order. The atomic charges obtained from the Mulliken and natural population analysis is used to assess the charge transfer effects that accompany the dimer formation. It is found from the investigation that the dimers having highest binding energy are accompanied by the highest transfer of charge. The 14N nuclear quadrupole coupling constants of the monomer ON1CCN2 are found to be decreased upon complection and in the series it increases from F through Br. We observed enhancements in the values of the dimer dipole moment and intrinsic dipole polarizabilities compared with the sum of the monomer values by intermolecular electrical interaction. Investigation reveals vibrational spectral shifts of HX and CN stretching modes similar to the conventional red-shifted H-bonded dimers; for the former case, the infrared band intensity increases significantly. Finally, the new vibrational modes originated from the intermolecular interaction are outlined.

  3. Thermodynamic investigation of the ternary mixed aqueous electrolyte (MgCl2 + MgSO4) system by potentiometric method at T = 298.15 K

    International Nuclear Information System (INIS)

    Highlights: → In this study we investigated the thermodynamic properties of MgCl2 + MgSO4 + H2O. → The method used in this work was potentiometric method. → Mg-ISE and the Ag/AgCl electrodes used in this work had a good Nernst response. → The experimental results obeyed the Harned rule. → The Pitzer model could be used to describe this ternary system satisfactorily. - Abstract: This work reports the results of thermodynamic investigation of the ternary mixed-electrolyte system (MgCl2 + MgSO4 + H2O). The investigation was performed based on Pitzer ion interaction model by using the potentiometric technique at T = 298.15 K. The mean activity coefficients of MgCl2 in the mixed aqueous electrolyte system were determined on the galvanic cell without liquid junction of the type: Mg-ISE|MgCl2 (mA), MgSO4 (mB), H2O|Ag/AgCl over total ionic strengths from (0.001 to 8.000) mol . kg-1 for different series of salt ratio r (r=mMgCl2/mMgSO4=2.5,5.0,7.5,10.0,15.0 and pure MgCl2). The PVC based magnesium ion-selective electrode (Mg-ISE) and the Ag/AgCl electrode used in this work were made in our laboratory and had a reasonably good Nernst response. The experimental results obeyed the Harned rule, and the Pitzer model could be used to describe this ternary system satisfactorily. Pitzer ion-interaction parameters for mixed salts were determined for this system. Then, these parameters (θClSO4=0.0252±0.0042, ψMgClSO4=-0.0049±0.0003) were used to calculate the values of the mean activity coefficients of MgSO4, the osmotic coefficients of water (φ) and the excess Gibbs free energies of solution (GE) for the whole series of the studied electrolyte systems.

  4. Spatial Fourier-decomposition optical fluorescen tomography-theoretical investigation

    Institute of Scientific and Technical Information of China (English)

    Cheng Liu; Dug Young Kim; Jianqiang Zhu

    2008-01-01

    A new three-dimensional (3D) optical fluorescent tomographic imaging scheme is proposed with structured illumination and spatial Fourierdomain decomposition methods for the first time. In this spatial Fourier-decomposition optical fluorescence tomography (SF-OFT), the intensity of focused excitation light from an objective lens is modulated to be a cosine function along the optical axis of the system. For a given position in a two-dimensional (2D) raster scanning process, the spatial frequency of the cosine function along the optical axis sweeps in a proper range while a series of fluorescence intensity are detected accordingly. By making an inverse discrete cosine transformation of these recorded intensity profiles, the distribution of fluorescent markers along the optical axis of a focused laser beam is obtained. A 3D optical fluorescent tomography can be achieved with this proposed SF-OFT technique with a simple 2D raster scanning process.

  5. Rovibrational states of ClHCl- isotopologues up to high J: a joint theoretical and spectroscopic investigation.

    Science.gov (United States)

    Sebald, Peter; Oswald, Rainer; Botschwina, Peter; Kawaguchi, Kentarou

    2013-05-14

    Explicitly correlated coupled cluster theory at the CCSD(T*)-F12b level (T. B. Adler, G. Knizia, and H.-J. Werner, J. Chem. Phys., 2007, 127, 221106) and two precise spectroscopic parameters (K. Kawaguchi, J. Chem. Phys., 1988, 88, 4186) were used to construct an accurate near-equilibrium analytical potential energy function (PEF) for the highly anharmonic centrosymmetric hydrogen-bonded complex ClHCl(-) (Re = 3.1153 Å). From variational calculations with that PEF, a large number of rovibrational energies of different isotopologues up to high values of the rotational quantum number J was obtained. Theory helped with the assignment of lines observed by IR diode laser spectroscopy in the ν1 + ν3 combination band of (35)ClH(35)Cl(-) and (37)ClH(35)Cl(-) and enabled us to elucidate rather subtle patterns of rovibrational interactions. Furthermore, transition dipole moments were predicted and analysed as well as unusual isotopic effects. PMID:23549111

  6. Elaboration and Characterization of AuCl Semiconductor Nanocrystals Embedded in KCL Single Crystals

    OpenAIRE

    Hanane Zaioune; Miloud Sebais; Fouzia Zehani

    2012-01-01

    In this work, we investigated the structural and the optical properties of AuCl semiconductor nanocrystals embedded in KCl single crystals. The AuCl nanocrystals were obtained by doping the KCl crystalline matrix with gold using the Czochralski method. The X-ray diffraction showed the formation of the AuCl nanocrystals in KCl with a tetragonal structure. The average radius of the AuCl nanocrystals is estimated using the Scherrer formula. The photoluminescence spectra presented a band emission...

  7. Thermodynamic investigation of the ternary mixed electrolyte (CoCl2 + CoSO4 + H2O) system by EMF measurements at T = 298.15 K

    International Nuclear Information System (INIS)

    In this work, the ternary mixed electrolyte system (CoCl2 + CoSO4 + H2O) was investigated based on the Pitzer ion-interaction model by using the potentiometric technique at T = 298.15 K. The mean activity coefficients of CoCl2 in the mixed aqueous electrolyte system were determined on the galvanic cell without liquid junction of the type: Co-ISE|CoCl2 (mA), CoSO4 (mB), H2O|Ag/AgCl over total ionic strengths from (0.001 to 6.000) mol . kg-1 for different series of salt ratio r (r=mCoCl2/mCoSO4=1.00,2.50,5.00,10.00 and pure). The PVC based cobalt ion-selective electrode (Co-ISE) and the Ag/AgCl electrode used in this work were made in our laboratory and had a reasonably good Nernst response. The experimental results obeyed the Harned rule, and the Pitzer model could be used to describe this ternary system satisfactorily. Furthermore, the parameters obtained with the Pitzer model (θClSO4=0.0719±0.0099,ψCoClSO4=0.0088±0.0003) were used to calculate the values of the mean activity coefficients of CoSO4, the osmotic coefficients of water (φ) and the excess Gibbs free energies of solution (GE) for the whole series of the studied electrolyte systems.

  8. Investigation on the nature of active species in the CeCl{sub 3}-doped sodium alanate system

    Energy Technology Data Exchange (ETDEWEB)

    Fan Xiulin; Xiao Xuezhang [Department of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027 (China); Chen Lixin, E-mail: lxchen@zju.edu.cn [Department of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027 (China); Li Shouquan; Wang Qidong [Department of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027 (China)

    2011-09-15

    Research highlights: > The additive of CeCl{sub 3} is reduced in doping process, causing the formation of NaCl and highly dispersed Ce species. > After dehydrogenation, Al-Ce alloy with a structure of CeAl{sub 4} comes into being and remains almost unchanged in the following cycles. > Directly doping CeAl{sub 4} into the system results in much similar kinetics. - Abstract: CeCl{sub 3}-doped NaAlH{sub 4} was directly synthesized in hydrogenation process using NaH/Al with 2 mol% CeCl{sub 3} under ball-milling. X-ray diffraction was utilized to unveil the nature of cerium during NaAlH{sub 4} synthesis process and succedent cycling. It is found that, CeCl{sub 3} is reduced in the ball-milling process and following cycles, causing the formation of NaCl and Al-Ce alloy with a structure of CeAl{sub 4}. The catalytic enhancement arising upon doping the ball-milled CeAl{sub 4} alloy is quite similar to that achieved in the CeCl{sub 3}-doped sodium alanate. Because the CeAl{sub 4} dopant does not consume the effective hydrogen storage component, the CeAl{sub 4}-doped NaAlH{sub 4} exhibits more hydrogen storage capacity. Moreover, CeCl{sub 3}-doped NaAlH{sub 4} and CeAl{sub 4}-doped NaAlH{sub 4} exhibit similar apparent activation energies estimated from Kissinger's method, suggesting the reactions are all determined by the same rate-limiting step. These results clearly demonstrate that the in situ formed CeAl{sub 4} acts as active species to catalyze the reversible dehydriding/rehydriding of NaAlH{sub 4}.

  9. Optogenetics: a novel optical manipulation tool for medical investigation

    OpenAIRE

    Yao, Jun-Ping; Hou, Wen-Sheng; Yin, Zheng-Qin

    2012-01-01

    Optogenetics is a new and rapidly evolving gene and neuroengineering technology that allows optical control of specific populations of neurons without affecting other neurons in the brain at high temporal and spatial resolution. By heterologous expression of the light-sensitive membrane proteins, cell type-specific depolarization or hyperpolarization can be optically induced on a millisecond time scale. Optogenetics has the higher selectivity and specificity compared to traditional electrophy...

  10. Study of optical properties of protactinium IV (5f1) in ThBr4 and ThCl4 matrices

    International Nuclear Information System (INIS)

    This thesis introduces spectroscopy studies of a (IV) which are realized in ThBr4 and ThCl4 host matrices. The optical polarized spectra are reported in the infrared region between 4.2K and 300K. The most important point is the first observation of the Pa4+ fluorescence spectrum. We determined experimentally the energy of all the Stark levels of tetrapositive protactinium ion doped into ThBr4. Consequently the values of the crystal field parameters and the spin-orbit coupling constant are deduced. The same behaviour for Pa4+:ThBr4 and Pa4+:ThCl4 characterized different interactions when the electron (5f1) comes in a different crystal field

  11. Theoretical study of the structures and first hyperpolarizabilities of C60Cl n and Li@C60Cl n (n = 4, 6, 8, 10).

    Science.gov (United States)

    Song, Yao-Dong; Wang, Liang; Wu, Li-Ming

    2016-06-01

    We recently reported (Song Y-D et al., 2016, J Mol Model 22:50) that doping with Li greatly affects the static first hyperpolarizability of C60Cl2. In this work, with a view to creating nonlinear optical materials with high thermodynamic stability and wide transparent regions, a series of Li@C60Cl n (n = 4, 6, 8, 10) were designed. The structures, electrostatic potentials, electronic structures, absorption spectra, and linear and nonlinear optical properties of C60Cl n and Li@C60Cl n were systematically investigated using density functional theory (DFT) methods. The results of our calculations indicated that the stability of these molecules decreases in the order Li@C60Cl10 > Li@C60Cl8 > Li@C60Cl6 > Li@C60Cl4. It is clear that the number of Cl atoms greatly influences the stability of Li@C60Cl n . Li@C60Cl n showed greater thermodynamic stability than Li@C60Cl2. We also investigated the first hyperpolarizabilities of Li@C60Cl n and found them to be 2973, 3640, 4307, and 2627 au for n = 4, 6, 8, and 10, respectively-higher than that of Li@C60Cl2. Finally, we noted that the transparent region could be modulated by increasing the number of Cl atoms: Li@C60Cl n possess wider transparent regions than that of Li@C60Cl2. We therefore believe that this study has highlighted an effective method for designing nonlinear optical materials with high thermodynamic stability and wide transparent regions. PMID:27188724

  12. Optical and spectroscopic investigation on Calcium Borotellurite glass system

    Science.gov (United States)

    Paz, E. C.; Lodi, T. A.; Gomes, B. R. A.; Melo, G. H. A.; Pedrochi, F.; Steimacher, A.

    2016-05-01

    In this work, the glass formation in Calcium Borotellurite (CBTx) system and their optical properties were studied. Six glass samples were prepared by melt-quenching technique and the samples obtained are transparent, lightly yellowish, without any visible crystallites. The results showed that TeO2 addition increases the density, the electronic polarizability and, consequently, the refractive index. The increase of electronic polarizability and optical basicity suggest that TeO2 addition increases the non-bridging oxygen (NBO) concentration. The increase of TeO2 shifts the band edge to longer wavelength owing to increase in non-bridging oxygen ions, resulting in a linear decrease of optical energy gap. The addition of TeO2 increases the temperature coefficient of the optical path length (dS/dT) in room temperature, which are comparable to phosphate and lower than Low Silica Calcium Alumino Silicate (LSCAS) glasses. The values of dS/dT present an increase as a function of temperature for all the samples measured. The results suggest that CBTx is a good candidate for rare-earth doping and several optical applications.

  13. Investigations on birefringence effects in polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Hu, Xiaolian; Saez-Rodriguez, D.; Bang, Ole;

    2014-01-01

    Step-index polymer optical fiber Bragg gratings (POFBGs) and microstructured polymer optical fiber Bragg gratings (mPOFBGs) present several attractive features, especially for sensing purposes. In comparison to FBGs written in silica fibers, they are more sensitive to temperature and pressure...... because of the larger thermo-optic coefficient and smaller Young's modulus of polymer materials. (M)POFBGs are most often photowritten in poly(methylmethacrylate) (PMMA) materials using a continuous-wave 325 nm HeCd laser. For the first time to the best of our knowledge, we study photoinduced...... birefringence effects in (m)POFBGs. To achieve this, highly reflective gratings were inscribed with the phase mask technique. They were then monitored in transmission with polarized light. For this, (m)POF sections a few cm in length containing the gratings were glued to angled silica fibers. Polarization...

  14. Fiber-Optic Network Architectures for Onboard Avionics Applications Investigated

    Science.gov (United States)

    Nguyen, Hung D.; Ngo, Duc H.

    2003-01-01

    This project is part of a study within the Advanced Air Transportation Technologies program undertaken at the NASA Glenn Research Center. The main focus of the program is the improvement of air transportation, with particular emphasis on air transportation safety. Current and future advances in digital data communications between an aircraft and the outside world will require high-bandwidth onboard communication networks. Radiofrequency (RF) systems, with their interconnection network based on coaxial cables and waveguides, increase the complexity of communication systems onboard modern civil and military aircraft with respect to weight, power consumption, and safety. In addition, safety and reliability concerns from electromagnetic interference between the RF components embedded in these communication systems exist. A simple, reliable, and lightweight network that is free from the effects of electromagnetic interference and capable of supporting the broadband communications needs of future onboard digital avionics systems cannot be easily implemented using existing coaxial cable-based systems. Fiber-optical communication systems can meet all these challenges of modern avionics applications in an efficient, cost-effective manner. The objective of this project is to present a number of optical network architectures for onboard RF signal distribution. Because of the emergence of a number of digital avionics devices requiring high-bandwidth connectivity, fiber-optic RF networks onboard modern aircraft will play a vital role in ensuring a low-noise, highly reliable RF communication system. Two approaches are being used for network architectures for aircraft onboard fiber-optic distribution systems: a hybrid RF-optical network and an all-optical wavelength division multiplexing (WDM) network.

  15. Connected fit algorithm for optical investigations of large area coatings

    International Nuclear Information System (INIS)

    In large area coating by reactive sputtering the homogeneity of the growing films is often essential. This property tends to depend critically on the geometry of the process chamber, arrangement of the magnetrons and construction of the gas inlets. In order to identify new ways to improve sputter equipment, film homogeneity has to be thoroughly studied. Often optical methods can be used for this purpose. We demonstrate how optical measurements combined with a novel fit algorithm can be used to gain insight into the details of the reactive sputter process of tin doped indium oxide and open new ways for improvement of the sputter equipment

  16. Synthesis, crystal structure and optical property of a novel metal chalcohalide: ZnHg3Se2Cl4

    International Nuclear Information System (INIS)

    A novel chalcohalide ZnHg3Se2Cl4 has been synthesized through a solid state method and structurally characterized by single-crystal X-ray diffraction. It crystallizes in the acentric space group Cmc21 (No. 36) with cell parameters a=7.3262(8) Å, b=12.518(2) Å, c=11.3324(14) Å. The compound consists of 12-membered Hg6Se6 rings edge-sharing with six neighbored rings to construct a 2D layered network and the ZnCl4 tetrahedra are sandwiched between layers. TG-DTA measurement shows that the compound is thermally stable up to 300 °C. The band gap of the crystal is about 2.23 eV, and the crystal exhibits a broad transparent range from 0.56 to 13.8 µm. - Highlights: • A novel chalcohalide ZnHg3Se2Cl4 was synthesized by a solid state method. • The structure contains 12-membered Hg6Se6 rings and ZnCl4 tetrahedra. • The band gap of the as-prepared compound is about 2.23 eV

  17. Combined CL/EBIC/DLTS investigation of a regular dislocation network formed by Si wafer direct bonding

    International Nuclear Information System (INIS)

    Electrical levels of the dislocation network in Si and recombination processes via these levels were studied by means of the combination of grain-boundary deep level transient spectroscopy, grain-boundary electron beam induced current (GB-EBIC) and cathodoluminescence (CL). It was found two deep level traps and one shallow trap existed at the interface of the bonded interface; these supply the recombination centers for carriers. The total recombination probability based on GB-EBIC data increased with the excitation level monotonically; however, the radiative recombination based on D1-D2 CL data exhibited a maximum at a certain excitation level. By applying an external bias across the bonded interface, the CL signal of D-lines was enhanced dramatically. These results are consistent with our models about two channels of recombination via the trap levels

  18. Investigating alkoxysilane coverage and dynamics on the (104) and (110) surfaces of MgCl 2-supported Ziegler-Natta catalysts

    KAUST Repository

    Credendino, Raffaele

    2012-11-01

    In this work, we present a systematic DFT analysis of the effect of surface coverage on the coordination properties of alkoxysilanes to the (104) and (110) surfaces of MgCl 2. Furthermore, we investigated several possible migration pathways for alkoxysilane migration on the same surfaces. Our study clearly shows that complete coverage of the Mg vacancies on the surface by coordinating alkoxysilanes is hampered by steric repulsion between vicinally coordinated donor molecules. Our study clearly indicates that alkoxysilane migration between different MgCl 2 monolayers on the (104) and (110) surfaces requires donor dissociation. The same holds for alkoxysilane migration on a single (110) MgCl 2 monolayer. However, in the case of the (104) surface we found a very low energy pathway for alkoxysilane migration along the same monolayer. © 2012 American Chemical Society.

  19. Investigating phthalate and 1,3-diether coverage and dynamics on the (104) and (110) surfaces of MgCl2-supported Ziegler-Natta catalysts

    KAUST Repository

    Credendino, Raffaele

    2014-04-17

    In this work we present a systematic DFT analysis of the effect of surface coverage on the coordination properties of two industrial Lewis bases, dimethyl phthalate and 9,9-bis(methoxymethyl)fluorene, to the (104) and (110) surfaces of MgCl2. Further, we investigated several possible migration pathways for the migration of the Lewis bases on the same MgCl2 monolayer. Our study clearly shows that complete coverage of the Mg vacancies on the surface by coordinating dimethyl phthalate or 9,9-bis(methoxymethyl)fluorene is hampered by steric repulsion between vicinally coordinated donor molecules. Further, our study clearly indicates that both dimethyl phthalate and 9,9-bis(methoxymethyl) fluorene migration on the same MgCl2 monolayer on the (104) and (110) surfaces basically requires donor dissociation. © 2014 American Chemical Society.

  20. Theoretical investigation of structural properties of CuCl, CuBr and CuI compounds under hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Louhibi-Fasla, S.; Djabri, H. Rekab; Achour, H. [Laboratoire de Micro et de Nanophysique LaMiN - ENP d' ORAN, BP 1523, El M' Naouer, 31000 (Algeria); Kefif, K. [Laboratoire de Physique des Couches Minces et Matériaux pour l' Electronique, Université d' ORAN, Es-senia (Algeria)

    2013-12-16

    We have applied a recent version of the full potential linear muffin-tin orbitals method (FPLMTO) to study the structural properties of copper halides CuX (X=Cl, Br, I) under high pressure using the generalized gradient approximation (GGA) for the exchange and correlation potential by Perdew et al. Results are given for lattice parameters, bulk modulus and its first derivatives in the wurtzite(B4), zinc-blende (B3), CsCl (B2), rock-salt (B1), and PbO (B10) structures. The results of these calculations are compared with the available theoretical and experimental data.

  1. Effect of the pos-deposition annealing with CdCl2 on the optical, structural and morphological properties of CdTe-films grown by CSS

    International Nuclear Information System (INIS)

    A set of CdTe films grown by the CSS method were annealed in aCdCl2 atmosphere of during 5 min at 345, 365, 385, 405, 425, 435, 445 and 455 °C. The films were characterized before and after annealing by the SEM, EDS, X-ray, optical absorption and photoluminescence (PL) techniques. As the annealing temperature is increased a tendency to improve the Cd/Te ratio is observed. After the thermal treatment at 430 °C the films reach the stoichiometry. A deviation from stoichiometry appears again for annealing temperatures higher than 430 °C. The PL spectra of the films at 6.5 K exhibit two emission bands, one corresponds to the defects energy levels band (1.4–1.5 eV) and the other is located in the interval from 1.564 to 1.584 eV (pA). For annealing temperatures higher than 430 °C an increment in the intensity and energy position of pA is observed, while for annealing temperatures less than 430 °C the behavior is irregular. In the emission mechanisms of pA the expected impurities and/or native defects in the material such as the VTe, VCdClTe, CdTe and ClTe are involved.

  2. Electronic structure, lattice constant, optical and mechanical properties for NaCl-structured Ti-Al-N by density functional theory

    International Nuclear Information System (INIS)

    The electronic structure, lattice constant, optical and mechanical properties of NaCl-structured Ti-Al-N compounds were studied by density functional theory with the plane wave pseudopotential method. The calculation results indicated that in a NaCl-structured TiN containing dilute solvent Al, the calculated forming energy of the paired defects of substitute Al for Ti+N vacancy is -1.7325 eV per pair of defects, while that of the paired defects of substitute Al for N+Ti vacancy is -10.62 eV per pair of defects. In other words, the energetically preferred occupation sites of Al atoms are Ti sites. In relation to the reference system of TiN, the substitute Al atoms for Ti increased the charge transfer to N atoms, while Al for N decreased it. On the other hand, the substitute Al for Ti exhibits cationic while those for N exhibit anionic. The addition of Al into the cubic TiN resulted in much universe feature of the refractory index in the visible light regime. The calculated reflectivity indicates that TiN is colorful while (Ti3Al)N4 is gray. The smaller lattice constant, lower elastic properties (the elastic tensor, bulk modulus and Young modulus) and higher hardness of NaCl-structure (Ti3Al)N4, than those of TiN, were discussed in terms of effects of the substitute Al for Ti on its electronic structure

  3. Magnetic, resonance, and optical properties of Cu3Sm (SeO3)2O2Cl : A rare-earth francisite compound

    Science.gov (United States)

    Zakharov, K. V.; Zvereva, E. A.; Markina, M. M.; Stratan, M. I.; Kuznetsova, E. S.; Dunaev, S. F.; Berdonosov, P. S.; Dolgikh, V. A.; Olenev, A. V.; Klimin, S. A.; Mazaev, L. S.; Kashchenko, M. A.; Ahmed, Md. A.; Banerjee, A.; Bandyopadhyay, S.; Iqbal, A.; Rahaman, B.; Saha-Dasgupta, T.; Vasiliev, A. N.

    2016-08-01

    In this combined experimental and theoretical paper, we study the properties of Cu3Sm (SeO3)2O2Cl belonging to the francisite family of compounds, which are novel frustrated layered compounds. Cu3Sm (SeO3)2O2Cl is synthesized through a solid state reaction. Characterizations through measurements of magnetization, specific heat, X-band electron spin resonance, and rare-earth optical spectroscopy, establish that the compound orders antiferromagnetically at TN=35 K and undergoes a spin-reorientation phase transition at TC=8.5 K due to the interplay of anisotropies in transition metal and rare-earth subsystems. The ground state Kramers doublet of Sm is found to split only at T Cl .

  4. Magneto-optic investigation of MnBi films.

    Science.gov (United States)

    Lewicki, G.; Guisinger, J. E.

    1973-01-01

    Another variation in the preparation of MnBi films from double layers of the constituents is reported. The dependence of Faraday and Kerr rotations on both composition and film thickness in these films suggests a model wherein a reacted double layer is made up of four separate layers. The variance in magneto-optic constants of MnBi reported here and previously is resolved in terms of this model.

  5. Computer Controlled Dispersion Measurements and Investigation of New Optical Fibers

    OpenAIRE

    Sembito, Alex

    2014-01-01

    A dispersion measurement setup for short length fibers based on Mach Zehnder interferometer was automatized and tested using standard telecommunication fiber. This setup is based on low coherence sources which enable interference to occur only in a narrow wavelength range. Dispersion in new optical fibers such as Ge-doped fiber and Yb:Tm doped fiber were measured over the wavelength range 1700nm-2400nm. Two broadband sources: - a superluminiscent Tm-doped fiber source (ASE source) and a model...

  6. An ROV toolbox for optical and acoustical seabed investigations

    OpenAIRE

    Ludvigsen, Martin

    2010-01-01

    This thesis describes a set of optical and acoustical methods for documenting a research site using underwater vehicles. The need for observations in cold-water coral research has formed the design problem in this work. A common survey protocol template is developed to describe video-, bathymetry-, photo mosaic- and photogrammetry surveys. For photogrammetry, the body of knowledge is small, and it was necessary to develop a new method rather than adapting existing methods. Axiomatic design me...

  7. Investigations on Ultrafast Fiber-based Optical Gates

    OpenAIRE

    Marembert, Vincent

    2007-01-01

    In dieser Arbeit wurden zwei optische Schalter basierend auf Dispersion-verschobener Hoch-Nichtlinearer Faser (Dispersion-Shifted Highly Nonlinear Fibers) untersucht. In dem Nonlinear Optical Loop Mirror (NOLM) und in dem Kerr Schalter wird die Phase eines optischen Datenpulses durch Kreuzphasenmodulation (XPM) moduliert. XPM wird von einem zusammen mit dem Datenpuls propagierenden Steuerpuls induziert. Die Phasenänderung kann in eine Amplitudenänderung umgewandelt werden, wenn XPM in einem i...

  8. Investigation of the optical properties of ordered semiconductor materials

    Science.gov (United States)

    McCrae, Jack E., Jr.

    1997-11-01

    Optical Studies have been conducted upon CdGeAs2 and ZnGeP2, two of the most promising semiconductors being developed for mid-infrared non-linear optics applications. These experiments included photoluminescence (PL) studies of both compounds as well as photoreflectance (PR) measurements upon CdGeAs2. In addition, Hall effect measurements were carried out upon CdGeAs2, to aid in interpretation of the optical data. PL was measured as a function of laser power, sample temperature, and crystal orientation for CdGeAs2. One broad weak peak near 0.38 eV, and another somewhat narrower and often far brighter peak near 0.57 eV were found by low temperature (4 K) PL measurements. Strongly polarized PL was observed with the E field of the PL parallel to the material's c-axis. A polarization ratio as high as 6:1 was observed. PL on ZnGeP2 in the mid-IR revealed a previously unreported PL peak near 0.35 eV. PR measurements on CdCeAs2 allowed the estimation of the bandgap as a function of temperature. The low temperature bandgap proved to be lower than that reported for electroreflectance measurements on other samples of this compound. Hall effect measurements on CdGeAs2 reveals the dominant acceptor level lies about 120 meV above the valence band.

  9. Optical investigation of heat release and NOx production in combustion

    International Nuclear Information System (INIS)

    Two novel optical techniques are presented for non-intrusive, spatially resolved study of combustion, both based on passive Optical Emission Tomography (OET). Firstly, OET is used for non-intrusive study of heat release through the detection of chemiluminescence by the hydroxyl radical that is generated in the burning process. The OET technique presented here is based on a passive fibre-optic detection system, which allows spatially resolved high-frequency detection of the flame front in a combustion flame, where all fibres detect the emission signals simultaneously. The system withstands the high pressures and temperatures typically encountered in the harsh environments of gas turbine combustors and IC engines. The sensor-array is non-intrusive, low-cost, compact, simple to configure and can be quickly set up around a combustion field. The maximum acquisition rate is 2 kHz. This allows spatially resolved study of the fast phenomena in combustion. Furthermore, a method is presented for study of the production of NOx through chemiluminescence from tri-methyl-borate (TMB). In combustion, the tri-methyl-borate produces green luminescence in locations where NOx would be produced. Combining the green luminescence visualisation with UV detection of the hydroxyl radical allows monitoring of heat release and of NOx production areas, thus giving a means of studying both the burning process and the resulting NOx pollution

  10. NONLINEAR OPTICAL PHENOMENA: Anomalous large nonlinearity of thin SnCl2 phthalocyanine films observed upon pulsed laser excitation

    Science.gov (United States)

    Borshch, A. A.; Brodin, M. S.; Verbitskii, A. B.; Vertsimakha, Ya I.; Volkov, V. I.; Lyakhovetskii, V. R.

    2002-02-01

    The nonlinear susceptibility of thin stannum dichloride phthalocyanine (SnCl2Pc) films was studied by the method of degenerate four-wave mixing (DFWM) using the second-harmonic 532-nm, 10-ns pulses from a single-mode, TEM00, 1.5-mJ Nd3+:YAG laser and by the method of nonlinear lens (the Z-scan method). The intensity of the first-order self-diffraction upon the DFWM on dynamic gratings induced in SnCl2Pc films has a cubic dependence on the recording-beam intensity, indicating to the third-order nonlinear response of the films. The value of the nonlinear susceptibility χ(3)(ωω,-ω,ω)=(4.4 ± 0.5) × 10-7 esu noticeably exceeds this value for phthalocyanines known in the literature. The mechanisms that can be responsible for the nonlinear response of the new synthesised material are discussed.

  11. Syntheses, crystal structures, and optical properties of Pb6B3O10X (X=F, Cl, Br)

    International Nuclear Information System (INIS)

    A series of lead-containing halogen oxyborates, Pb6B3O10X (X=F, Cl, Br), have been grown by high-temperature solution method and their crystal structures were determined by single-crystal X-ray diffraction. They are isostructural and crystallize in the space group Pbcm of the orthorhombic crystal system. The crystal structures are dominated by one-dimensional ∞[(Pb4O)(BO3)3] “Zig-Zag”-chains, while the remaining Pb atoms and X (X=F, Cl, Br) atoms are filled to balance the charge. Compared with the previously reported compound Pb4O(BO3)2 (the molecular formula Pb4O(BO3)2 can be regarded as Pb6B3O10.5) with the space group Aba2, the structures of Pb6B3O10X (X=F, Cl, Br) are completely different from that of Pb4O(BO3)2. IR spectroscopy, UV–vis-NIR diffuse reflectance spectroscopy, thermal analysis, and theoretical calculations were also performed on the reported materials. Highlights: • A new family of lead-containing halogen oxyborates, Pb6B3O10X (X=F, Cl, Br), have been grown by high-temperature solution method. • Owing to the introduction of X atoms into Pb4O(BO3)2, the structures of Pb6B3O10X are completely different. The crystal structures are dominated by one-dimensional ∞[(Pb4O)(BO3)3] “Zig-Zag”-chains

  12. Multimodal optical imaging system for in vivo investigation of cerebral oxygen delivery and energy metabolism

    OpenAIRE

    Yaseen, Mohammad A.; Vivek J Srinivasan; Gorczynska, Iwona; Fujimoto, James G.; Boas, David A.; Sakadžić, Sava

    2015-01-01

    Improving our understanding of brain function requires novel tools to observe multiple physiological parameters with high resolution in vivo. We have developed a multimodal imaging system for investigating multiple facets of cerebral blood flow and metabolism in small animals. The system was custom designed and features multiple optical imaging capabilities, including 2-photon and confocal lifetime microscopy, optical coherence tomography, laser speckle imaging, and optical intrinsic signal i...

  13. Synthesis, structural and optical characterization of APbX3 (A=methylammonium, dimethylammonium, trimethylammonium; X=I, Br, Cl) hybrid organic-inorganic materials

    Science.gov (United States)

    Mancini, Alessandro; Quadrelli, Paolo; Amoroso, Giuseppe; Milanese, Chiara; Boiocchi, Massimo; Sironi, Angelo; Patrini, Maddalena; Guizzetti, Giorgio; Malavasi, Lorenzo

    2016-08-01

    In this paper we report the synthesis, the crystal structure and the optical response of APbX3 (A=MA, DMA, and TMA; X=I, Br) hybrid organic-inorganic materials including some new phases. We observe that as the cation group increases in size, the optical absorption edge shifts to higher energies with energy steps which are systematic and independent on the anion. A linear correlation between the optical bad gap and the tolerance factor has been shown for the series of samples investigated.

  14. Viscosimetric investigations of NaCl and NaBr in hexamethylphosphoramidc-water mixtures at 298.15 K

    OpenAIRE

    Jóżwiak, Małgorzata

    1991-01-01

    This work was supported by the CPBP 01.15 programme of Ministry of Higher Education, Poland The maesurements of density and viscosity of hexamethylphosphoramida (HMPA)-water mixtures containing NaCl and NaBr were performed at 298.15 K. The B-coefficients of the Jones-Dole equation were calculated. The relative viscosity and the B-coefficient are discussed in this work together with the standard enthalpy of solution of the electrolytes in HMPA-H₂O mixtures at 298.15 K. Prz...

  15. Investigation of outer valence orbital of CF2Cl2 by a new type of electron momentum spectrometer

    Institute of Scientific and Technical Information of China (English)

    Ning Chuan-Gang; Ren Xue-Guang; Deng Jing-Kang; Su Guo-Lin; Zhang Shu-Feng; Huang Feng; Li Gui-Qin

    2005-01-01

    Electronic states of CF2Cl2 (dichlorodifluoromethane, Freon 12) have been studied using a new type of electron momentum spectrometer with a very high efficiency at an impact energy of 1200 eV plus binding energy. The experimental electron momentum profiles are compared with the density functional theory (DFT) and Hartree-Fock (HF)calculations. The relationship between orbital assignments in different coordinate systems is discussed. A new method of difference analysis based on the new type of electron momentum spectrometer is used to clarify the ambiguities regarding the orbital ordering.

  16. Toward Investigating Optically Trapped Organic Aerosols with CARS Microspectroscopy

    Science.gov (United States)

    Voss, L. F.

    2009-12-01

    The Intergovernmental Panel on Climate Change notes the huge uncertainty in the effect that atmospheric aerosols play in determining overall global temperature, specifically in their ability to nucleate clouds. To better understand aerosol chemistry, the novel coupling of gradient force optical trapping with broad bandwidth coherent anti-Stokes Raman scattering (CARS) spectroscopy is being developed to study single particles suspended in air. Building on successful designs employed separately for the techniques, this hybrid technology will be used to explain how the oxidation of organic compounds changes the chemical and physical properties of aerosols. By trapping the particles, an individual aerosol can be studied for up to several days. Using a broad bandwidth pulse for one of the incident beams will result in a Raman vibrational spectrum from every laser pulse. Combined with signal enhancement due to resonance and coherence of nonlinear CARS spectroscopy, this technique will allow for acquisition of data on the millisecond time scale, facilitating the study of dynamic processes. This will provide insights on how aerosols react with and absorb species from the gas phase. These experiments will increase understanding of aerosol oxidation and growth mechanisms and the effects that aerosols have on our atmosphere and climate. Progress in efforts developing this novel technique to study model systems is presented.

  17. Investigation of in vitro dental erosion by optical techniques.

    Science.gov (United States)

    Thomas, Shiny S; Mallia, Rupananda J; Jose, Mini; Subhash, Narayanan

    2008-07-01

    Nitrogen laser-induced fluorescence (LIF) and tungsten halogen lamp excited diffuse reflectance spectra were recorded in 350- to 700-nm range on a miniature fiber-optic spectrometer from in vitro premolar tooth during various stages of artificial erosion with 36% phosphoric acid. Both the LIF spectral intensity and the diffuse reflectance intensity gradually increased during tooth erosion. The LIF spectra were analyzed by curve fitting using Gaussian spectral functions to determine the true contribution of different bands in the spectra during erosion. Thus, the broad bands at 440 and 490 nm in the LIF spectra of sound enamel were resolved into four peaks centered at 409.1, 438.1, 492.4 and 523.1 nm and of sound dentin into peaks at 412.0, 440.1, 487.8 and 523.4 nm. The F410/F525 ratios derived from curve-fitted Gaussian peak amplitudes and curve areas were found to be more sensitive to erosion as compared to the diffuse reflectance ratio R500/R700 or the raw LIF spectral ratio F440/F490. PMID:17786500

  18. Investigation of diffractive optical element femtosecond laser machining

    Science.gov (United States)

    Chabrol, Grégoire R.; Ciceron, Adline; Twardowski, Patrice; Pfeiffer, Pierre; Flury, Manuel; Mermet, Frédéric; Lecler, Sylvain

    2016-06-01

    This paper presents an explorative study on the machining of diffractive optical elements (DOEs) in transparent materials using a femtosecond laser source. A simple form of DOE, a binary phase grating with a period of 20.85 μm (σ = 0.5 μm), a groove depth and width of 0.7 μm (σ = 0.2 μm) and 8.8 μm (σ = 0.5 μm) respectively, was successfully machined in BK7. The topographic characteristics were measured by white light interferometry and scanning electron microscopy (SEM). The processing was carried out on high precision stages with an ultrafast fibre laser (350 fs) emitting a 343 nm pulse focused onto the sample with a stationary microscope objective. A diffracted efficiency of 27%, obtained with a spectro goniometer, was corroborated by the theoretical results obtained by the Fourier modal method (FMM), taking into account the measured topographic values. These encouraging results demonstrate that high-speed femtosecond laser manufacturing of DOE in bulk glasses can be achieved, opening the way to rapid prototyping of multi-layered-DOEs.

  19. Optical photometric and polarimetric investigation of NGC 1931

    CERN Document Server

    Pandey, A K; Sharma, Saurabh; Samal, M R; Chauhan, N; Chen, W P; Jose, J; Ojha, D K; Yadav, Ram Kesh; Chandola, H C

    2013-01-01

    We present optical photometric and polarimetric observations of stars towards NGC 1931 with the aim to derive the cluster parameters such as distance, reddening, age and luminosity/mass function as well as to understand the dust properties and star formation in the region. The distance to the cluster is found to be 2.3$\\pm$0.3 kpc and the reddening E(B-V) in the region is found to be variable. The stellar density contours reveal two clustering in the region. The observations suggest differing reddening law within the cluster region. Polarization efficiency of the dust grains towards the direction of the cluster is found to be less than that for the general diffuse interstellar medium (ISM). The slope of the mass function (-0.98$\\pm$0.22) in the southern region in the mass range 0.8 \\textless $M/M_{\\sun}$ $\\textless$ 9.8 is found to be shallower in comparison to that in the northern region (-1.26$\\pm$0.23), which is comparable to the Salpeter value (-1.35). The K-band luminosity function (KLF) of the region is...

  20. Investigation of Optical Properties of Biomolecular Materials for Developing a Novel Fiber Optic Biosensor.

    Science.gov (United States)

    Gao, Harry Hong

    1995-01-01

    Recently considerable efforts have been devoted to the development of optical biosensors for applications such as environmental monitoring and biomedical technology. The research described in this thesis focuses on the development of a novel fiber optic biosensor system for pesticide detection based on enzyme catalyzed chemiluminescence. To optimize the collection efficiency, the tapering effect of a fiber tip has been studied in different cases of light source distribution utilizing fluorescence technique. Our results indicate that a continuously tapered tip with the largest tapering angle is the most efficient configuration when the light source is in a "thick" layer ({> }1 μm) while a combination tapered tip is the best configuration when the light source is either in a thin layer ({alkaline phosphatase have been characterized using various techniques including chemiluminescence, ellipsometry and surface plasma resonance. The results indicated that at least 3 layers of enzyme can be assembled on a fiber surface. With this approach, it is possible to immobilize different kinds of enzyme on a fiber surface for biosensors based on a multi-enzyme system. Based on the studies of tapered tip and immobilization schemes, a novel fiber optic biosensor system for the detection of organophosphorous-based pesticide has been developed. The detection mechanism is pesticide inhibition of alkaline phosphatase catalyzed chemiluminescence. Paraoxon with concentration as low as 167 ppb has been detected. This is the first fiber optic chemiluminescence-based biosensor utilizing tapered tips with enzyme immobilized on the fiber surface and a cooled CCD array detector.

  1. Multiple bonds to gold: a theoretical investigation of XAuC (X = F, Cl, Br, I) molecules

    International Nuclear Information System (INIS)

    Structures and spectroscopic properties are reported for the linear XAuC (X = F, Cl, Br, I) series of molecules and their related diatomic species at a high level of accuracy. The singles and doubles coupled cluster method including a perturbational correction for connected triple excitations, CCSD(T), with systematic sequences of new correlation consistent basis sets have been employed. Scalar relativistic effects have been accurately included by making use of relativistic effective core potentials. Extrapolation to the complete basis set limit has been used with accurate treatments of core-valence correlation and spin-orbit effects in order to accurately predict spectroscopic properties, as well as dissociation and atomization energies at 0 K of AuC, AuC+, AuF, AuCl, AuBr, AuI, and the XAuC molecules. The Au-C bond length in the FAuC molecule is predicted to be nearly identical to that calculated for AuC+, which makes it the shortest known for a neutral gold molecule. The Au-C and Au-F (0 K) bond dissociation energies in FAuC are predicted to be 92.5 and 93.1 kcal/mol, respectively, also making them some of the strongest known bonds to gold

  2. Study of NaCl:Mn{sup 2+} nanostructures in the Suzuki phase by optical spectroscopy and atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mejía-Uriarte, E.V., E-mail: elsi.mejia@ccadet.unam.mx [Laboratorio de Fotónica de Microondas, Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, AP 70-186, C.P. 04510, D.F. México (Mexico); Kolokoltsev, O. [Laboratorio de Fotónica de Microondas, Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, AP 70-186, C.P. 04510, D.F. México (Mexico); Navarrete Montesinos, M. [Instituto de Ingeniería, Universidad Nacional Autónoma de México, D.F. México (Mexico); Camarillo, E.; Hernández A, J.; Murrieta S, H. [Instituto de Física, Universidad Nacional Autónoma de México, AP 20-364, C.P. 01000, D.F. México (Mexico)

    2015-04-15

    NaCl:Mn{sup 2+} nanostructures in the Suzuki phase have been studied by fluorescence (emission and excitation) spectroscopy and atomic force microscopy (AFM) as a function of temperature. The “as-grown” samples give rise to two broad emission bands that peak at 508 (green emission) and 610 nm (red emission). The excitation spectrum shows peaks at 227 nm and 232 nm for emission wavelengths at 508 nm and 610 nm, respectively. When the samples are heated continuously from room temperature up to 220 °C, the green emission (associated to the excitation peak at 227 nm) disappears at a temperature close to 120 °C, whilst only the red emission remains, which is characteristic of manganese ions. AFM images on the (0 0 1) surface (freshly cleaved) show several conformations of nanostructures, such as disks of 20–50 nm in diameter. Particularly, the images also reveal nanostructures with rectangular shape of ~280×160 nm{sup 2} and ~6 nm height; these are present only in samples with green emission associated to the Suzuki phase. Then, the evidence suggests that this topographic configuration might be related to the interaction with the first neighbors and the next neighbors, according to the configuration that has been suggested for the Suzuki phase. - Highlights: • NaCl:Mn{sup 2+} single crystals in the Suzuki phase contain rectangular nanostructures. • Double emission of manganese ions: green (508 nm) and red (610 nm) bands. • The excitation peak at 227 nm is attributed to rectangular nanostructures. • The green emission band associated to Suzuki phase is extinguished at 120 °C.

  3. Optical properties of the alkaline-earth fluorohalides matlockite-type structure SrFX (X=Cl, Br, I) compounds

    International Nuclear Information System (INIS)

    The optical properties of the SrFX (X=Cl, Br, I) compound have been reported using the full potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2K code. We employed the generalized gradient approximation (GGA), which is based on exchange-correlation energy optimization to calculate the total energy. Also we have used the Engel-Vosko GGA formalism, which optimizes the corresponding potential for band structure calculations. Our calculations show that the valence band maximum (VBM) and conduction band minimum (CBM) are located at Γ resulting in a direct energy gap. We present calculations of the frequency-dependent complex dielectric function ε(ω) and its zero-frequency limit ε1(0). We find that the value of ε1(0) increases on decreasing the energy gap. The reflectivity spectra and absorption coefficient have been calculated and compared with the available experimental data

  4. OPTICAL PHOTOMETRIC AND POLARIMETRIC INVESTIGATION OF NGC 1931

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, A. K.; Eswaraiah, C.; Sharma, Saurabh; Yadav, Ram Kesh [Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital 263129 (India); Samal, M. R. [Laboratoire d' Astrophysique de Marseille-LAM, Universite d' Aix-Marseille and CNRS, UMR7326, F-13388 Marseille Cedex 13 (France); Chauhan, N.; Chen, W. P. [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Jose, J. [Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India); Ojha, D. K. [Tata Institute of Fundamental Research, Mumbai 400 005 (India); Chandola, H. C., E-mail: pandey@aries.res.in [Department of Physics, Kumaun University, Nainital 263129 (India)

    2013-02-20

    We present optical photometric and polarimetric observations of stars toward NGC 1931 with the aim of deriving cluster parameters such as distance, reddening, age, and luminosity/mass function as well as understanding dust properties and star formation in the region. The distance to the cluster is found to be 2.3 {+-} 0.3 kpc and the reddening E(B - V) in the region is found to be variable. The stellar density contours reveal two clusters in the region. The observations suggest a differing reddening law within the cluster region. Polarization efficiency of the dust grains toward the direction of the cluster is found to be less than that for the general diffuse interstellar medium (ISM). The slope of the mass function (-0.98 {+-} 0.22) in the southern region in the mass range of 0.8 < M/M {sub Sun} < 9.8 is found to be shallower in comparison to that in the northern region (-1.26 {+-} 0.23), which is comparable to the Salpeter value (-1.35). The K-band luminosity function (KLF) of the region is found to be comparable to the average value of the slope ({approx}0.4) for young clusters obtained by Lada and Lada; however, the slope of the KLF is steeper in the northern region as compared to the southern region. The region is probably ionized by two B2 main-sequence-type stars. The mean age of the young stellar objects (YSOs) is found to be 2 {+-} 1 Myr, which suggests that the identified YSOs could be younger than the ionizing sources of the region. The morphology of the region, the distribution and ages of the YSOs, and ionizing sources indicate a triggered star formation in the region.

  5. Optical Properties of CuCl+-Implantation and Observation of Sub-micrometre Particles in α-Al2O3 Crystals

    Institute of Scientific and Technical Information of China (English)

    WANG Chun-Fen; LEI Jia-Rong; WANG De-Zhi; HUANG Ning-Kang

    2005-01-01

    @@ Crystal samples of α-Al2O3 were implanted in different crystalline orientations with CuCl+ at intensities from 6 × 1016 ions/cm2 to 5 × 1017 ions/cm2 and energies from 350 to 380keV at different temperatures. A strong absorption of UV section can be seen in optical absorption spectra for all of the specimens. Gaussian fitting for the absorption curves with luminescence measurements confirmed that there were point defects such as F, F+, F2+, and F2 centres in the CuCl+-implanted α-Al2O3 samples. It is found that the absorption intensity is decreased by annealing treatment, thus the number of the colour centres was decreased due to annealing. It is also found that the variety of colour centre number was dependent greatly on implantation conditions, substrate orientation and annealing temperature. Sub-micrometre particles after annealing have been observed by using the SEM technique.

  6. Applications of combinatorial approach to the investigation of optical functional materials

    Institute of Scientific and Technical Information of China (English)

    LUO ZhenLin; BAO Jun; DING JianJun; CHEN Lei; LI XueFei; JIU HongFang; ZHANG QiJin; CHAN TingShan; LIU RuXi; GAO Chen

    2009-01-01

    Recent applications of combinatorial methodology to the investigation of optical functional materials are reviewed on the basis of the authors' work. The content includes: basic concepts of combinatorial materials science, combinatorial investigations of UV/VUV excited photoluminescence, luminescent rear earth complex doped polymer and magneto-optical materials. The fundamental synthesis tech-niques and characterization methods in combinatorial methodology are also illustrated in the text.

  7. Investigation of the thermoluminescence of a Ge doped optical fibre

    International Nuclear Information System (INIS)

    A radiation dosimeter based on Ge-doped silica fibre is described. The parameters of thermoluminescence (TL) induced by Co-60 radiation in the silica fibre are investigated. These parameters include activation energies and frequency factors. The reproducibility of the fibre, dose response and fading, have also been investigated. We conclude that this fibre provides good basis for medical radiation dosimetry at therapy levels. In particular, doses are reproducible, the fibres are reusable and show linearity of dose versus TL output over the approximate range of dose 1 Gy to in excess of 100 Gy. At room temperature, fading within the first 30 days following irradiation was found to be of the order of 7 %. (author)

  8. Acoustic-optic investigations of acoustic gyrotropy in crystals

    International Nuclear Information System (INIS)

    For the experimental investigation of the acoustic activity the Bragg light diffraction method on transverse acoustic waves was used in the frequency range 0.4-1.8 GHz. It is shown that the oscillation period of the intensity of the diffracted light is defined by the specific rotator power of the crystal. On the basis of experimental data the specific rotation of the polarization plane in a number of gyrotropic crystals was determined. (authors)

  9. Investigation of Wide-FSR SOI Optical Filters Operating in C and L Bands

    Directory of Open Access Journals (Sweden)

    V. M. N. Passaro

    2012-06-01

    Full Text Available In this paper we present the investigation of optical filters based on triple ring resonator architectures in silicon-on-insulator technology. The generalized approach based on Mason’s rule and delay line signal processing has been implemented for modeling optical filters in Z-domain. A numerical investigation based on the coefficient map has been adopted for designing optical add-drop multiplexers with wide free spectral ranges, as large as 12 THz (~ 96 nm. Low crosstalk, of the order of -20 dB, has been numerically demonstrated in overall transmittances of optimized filters.

  10. Investigation of 160 Gbit/s optical communication systems

    DEFF Research Database (Denmark)

    Xu, Zhenbo

    2006-01-01

    In this thesis 160 Gbit/s per-channel transmission systems are investigated in the form of both single channel systems and WDM systems. The aim of the research is to identify the longest possible transmission distance, employing Raman amplification and to study advanced modulation formats. Numero...... management is discussed with regard to optimizing pre, post and in-line dispersion compensation along the fiber link. A comparison of optimal operating conditions for single channel systems and 5-channel WDM systems are given for various modulation formats.......In this thesis 160 Gbit/s per-channel transmission systems are investigated in the form of both single channel systems and WDM systems. The aim of the research is to identify the longest possible transmission distance, employing Raman amplification and to study advanced modulation formats. Numerous...... from a transmission system standpoint. The first section focuses on the discrete Raman amplification with estimation of system performance using four kinds of Raman pumping schemes. An optimal transmission distance of 1800 km is predicted. Moreover, signal pulse width, dispersion and effective core...

  11. Syntheses, crystal structures and optical properties of the first strontium selenium(IV) and tellurium(IV) oxychlorides: Sr3(SeO3)(Se2O5)Cl2 and Sr4(Te3O8)Cl4

    International Nuclear Information System (INIS)

    Two new quaternary strontium selenium(IV) and tellurium(IV) oxychlorides, namely, Sr3(SeO3)(Se2O5)Cl2 and Sr4(Te3O8)Cl4, have been prepared by solid-state reaction. Sr3(SeO3)(Se2O5)Cl2 features a three-dimensional (3D) network structure constructed from strontium(II) interconnected by Cl-, SeO32- as well as Se2O52- anions. The structure of Sr4(Te3O8)Cl4 features a 3D network in which the strontium tellurium oxide slabs are interconnected by bridging Cl- anions. The diffuse reflectance spectrum measurements and results of the electronic band structure calculations indicate that both compounds are wide band-gap semiconductors. - Graphical abstract: Solid-state reactions of SrO, SrCl2, and SeO2 or TeO2 in different molar ratios and under different temperatures lead to two new strontium selenium(IV) or tellurium(IV) oxychlorides with two different types of structures, namely, Sr3(SeO3)(Se2O5)Cl2 and Sr4(Te3O8)Cl4. Both compounds are wide band-gap semiconductors based on the diffuse reflectance spectra and the electronic band structures

  12. Investigations of GMAW plasma by optical emission spectroscopy

    International Nuclear Information System (INIS)

    We report on investigations of gas metal arc welding plasma operated in pure argon and in a mixture of argon and CO2 at a dc current of 326 A. The spatially resolved electron densities and temperatures were directly obtained by measuring the Stark widths of the Ar I 695.5 nm and Fe I 538.3 nm spectral lines. Our experimental results show a reduction of the plasma conductivity and transfer from spray arc to globular arc operation with increasing CO2 concentration. Although the electron density ne increases while approaching the core of the plasma in the spray-arc mode, a drop in the electron temperature Te is observed. Moreover, the maximum Te that we measure is about 13 000 K. Our experimental results differ from the Haidar model where Te is always maximum on the arc axis and its values exceed 20 000 K. These discrepancies can be explained as a result of underestimation of the amount of metal vapours in the plasma core and of the assumption of local thermal equilibrium plasma in the model

  13. Investigations of GMAW plasma by optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zielinska, S [Instytut Fizyki im. Mariana Smoluchowskiego, Uniwersytet Jagiellonski, ulica Reymonta 4, 30-059 Krakow (Poland); Musiol, K [Instytut Fizyki im. Mariana Smoluchowskiego, Uniwersytet Jagiellonski, ulica Reymonta 4, 30-059 Krakow (Poland); Dzierzega, K [Instytut Fizyki im. Mariana Smoluchowskiego, Uniwersytet Jagiellonski, ulica Reymonta 4, 30-059 Krakow (Poland); Pellerin, S [LASEP, Faculte des Sciences-Bourges, Universite d' Orleans, BP 4043, 18028 Bourges Cedex (France); Valensi, F [LASEP, Faculte des Sciences-Bourges, Universite d' Orleans, BP 4043, 18028 Bourges Cedex (France); Izarra, Ch de [LASEP, Faculte des Sciences-Bourges, Universite d' Orleans, BP 4043, 18028 Bourges Cedex (France); Briand, F [CTAS - Air Liquide Welding, Rue des Epluches, Saint Ouen l' Aumone (France)

    2007-11-15

    We report on investigations of gas metal arc welding plasma operated in pure argon and in a mixture of argon and CO{sub 2} at a dc current of 326 A. The spatially resolved electron densities and temperatures were directly obtained by measuring the Stark widths of the Ar I 695.5 nm and Fe I 538.3 nm spectral lines. Our experimental results show a reduction of the plasma conductivity and transfer from spray arc to globular arc operation with increasing CO{sub 2} concentration. Although the electron density n{sub e} increases while approaching the core of the plasma in the spray-arc mode, a drop in the electron temperature T{sub e} is observed. Moreover, the maximum T{sub e} that we measure is about 13 000 K. Our experimental results differ from the Haidar model where T{sub e} is always maximum on the arc axis and its values exceed 20 000 K. These discrepancies can be explained as a result of underestimation of the amount of metal vapours in the plasma core and of the assumption of local thermal equilibrium plasma in the model.

  14. Optical investigation of a sun simulator for concentrator PV applications.

    Science.gov (United States)

    Rapp, Christoph; Straub, Volker; van Rooyen, De Wet; Thor, Wei Yi; Siefer, Gerald; Bett, Andreas W

    2015-09-21

    In photovoltaics (PV), sun simulators are used to reproduce outdoor conditions in a lab environment such as irradiance level, light uniformity and spectral distribution. Concentrator (C)PV applications additionally require the sun simulators to provide rays with an angular distribution similar to that of the sun rays. However, different factors in CPV sun simulator setups make it difficult to achieve the perfect sun like angular distribution. This is mainly caused by the unavailability of appropriate light sources. Therefore, we investigated in this work, to which deviations such a non-ideal light source can lead and which impact is expected at the measurement of a CPV module. For this, two ray tracing models are presented - one for the simulation of natural sunrays, another one for the simulation of sun simulator conditions. The models are validated based on measurements and subsequently used to simulate the impact on a typical CPV module with silicone-on-glass Fresnel lenses. Here, significant deviations to outdoor conditions are found. PMID:26406756

  15. Investigation of Resolution and Phase Equilibria of NaCl-Ba(H2PO2)2-H2O Trio Salt-Water System at 25 °C Temperature with Isothermal Method

    OpenAIRE

    KUL, Ali Rıza; ERGE, Hasan; ÖZDEK, Uğur

    2014-01-01

    In the present research, solubility, density, conductivity and phase equilibria of Na2Cl2-Ba(H2PO2)2-H2O triple system existing in Na+, Ba+2/Cl-, (H2PO2)-H2O quadrangular mutual water-salt system were investigated by using physicochemical analysis methods. In the first place, 100 mL distilled water was added into a 100 mL volumetric flask and each time 7 g NaCl was added until solubility point of NaCl. Each addition was followed by mixing two hours and leaving one hour. Having established sol...

  16. Optical lifetime and linewidth studies of the {sup 7}F{sub 0}{yields}{sup 5}D{sub 0} transition in EuCl{sub 3}{center_dot}6H{sub 2}O: A potential material for quantum memory applications

    Energy Technology Data Exchange (ETDEWEB)

    Ahlefeldt, R.L., E-mail: rose.ahlefeldt@anu.edu.au [Centre for Quantum Computation and Communication Technology, Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200 (Australia); Manson, N.B. [Laser Physics Centre, Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200 (Australia); Sellars, M.J. [Centre for Quantum Computation and Communication Technology, Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200 (Australia)

    2013-01-15

    The effect of substituting deuterium for hydrogen in EuCl{sub 3}{center_dot}6H{sub 2}O on the lifetime and homogeneous and inhomogeneous linewidths of the {sup 7}F{sub 0}{yields}{sup 5}D{sub 0} transition at below 4 K are investigated. It is observed that the transition lifetime increases from 116{mu}s to 2.6 ms and the homogeneous linewidth decreases from 4.1 kHz to 430 Hz. The sensitivity of the inhomogeneous broadening to the residual hydrogen concentration is estimated to be 91 MHz/atm%. The potential of utilizing this crystal for quantum memory applications is discussed. - Highlights: Black-Right-Pointing-Pointer The optical lifetime of EuCl{sub 3}{center_dot}6H{sub 2}O increases 20 times with full deuteration. Black-Right-Pointing-Pointer An optical coherence time of 740{mu}s was observed in EuCl{sub 3}{center_dot}6D{sub 2}O. Black-Right-Pointing-Pointer High D purity EuCl{sub 3}{center_dot}6H{sub 2}O is a good candidate material for quantum memories.

  17. Development and investigation of a CPV module with Cassegrain mirror optics

    Science.gov (United States)

    Dreger, Max; Wiesenfarth, Maike; Kisser, Arne; Schmid, Tobias; Bett, Andreas W.

    2014-09-01

    One approach to concentrate the sunlight in concentrating photovoltaic (CPV) modules is using Cassegrain mirror optics. The advantage is that a passively cooled solar cell can be mounted to a large heat spreader that does not shade the primary optics. In addition, the height of the module, hence weight, can be low. The design was selected on the basis of the results of a design study comparing different CPV module approaches presented in [1]. In this work, we present the development of a new prototype micro dish module. First results of the characterization are shown. Besides of the electrical performance, a machined optics and an injection molded was investigated regarding sensitivity to misalignment errors between the optical elements as well as measurement of the acceptance angle in- and outdoors. The machined optics was used as reference.

  18. Terahertz Generation in an Electrically Biased Optical Fiber: A Theoretical Investigation

    Directory of Open Access Journals (Sweden)

    Montasir Qasymeh

    2012-01-01

    Full Text Available We propose and theoretically investigate a novel approach for generating terahertz (THz radiation in a standard single-mode fiber. The optical fiber is mediated by an electrostatic field, which induces an effective second-order nonlinear susceptibility via the Kerr effect. The THz generation is based on difference frequency generation (DFG. A dispersive fiber Bragg grating (FBG is utilized to phase match the two interacting optical carriers. A ring resonator is utilized to boost the optical intensities in the biased optical fiber. A mathematical model is developed which is supported by a numerical analysis and simulations. It is shown that a wide spectrum of a tunable THz radiation can be generated, providing a proper design of the FBG and the optical carriers.

  19. catena-Poly[cobalt(II-di-μ-chlorido-κ4Cl:Cl-μ-1,5-dimethyl-1H-tetrazole-κ2N3:N4]: an X-ray powder investigation

    Directory of Open Access Journals (Sweden)

    Oleg A. Ivashkevich

    2009-02-01

    Full Text Available The asymmetric unit of the title compound, [CoCl2(C3H6N4]n, contains two Co atoms, both lying on inversion centres, two Cl atoms and one 1,5-dimethyltetrazole ligand. The coordination polyhedra of both Co atoms adopt flattened octahedral geometry, with two N atoms from two ligands in axial positions and four Cl atoms in equatorial sites. Neighbouring Co atoms are linked together via two bridging Cl atoms and one tetrazole ring to form polymeric chains running along the a axis.

  20. Investigation of Cl corrosion products of iron archaeological artefacts using micro-focused synchrotron X-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Synchrotron-based micro-X-ray absorption spectroscopy is used in the present study to obtain chemical information at the microscopic scale such as coordination and oxidation state of Fe atoms in phases constituting corrosion products within archaeological iron artefacts buried in soil. This technique is required in order to answer questions about the iron corrosion process related to the presence of chloride, particularly for restoration and conservation of metallic artefacts of the cultural heritage. The samples available for X-ray microprobe analyses are cross sections from corroded iron archaeological objects. Previously, complementary techniques have been used such as μXRD and μRaman. This specific study applies micro-X-ray absorption spectroscopy to determine the spatial variation of the predominant Fe oxidation state and to identify the corresponding crystallographic phase. The analyses performed at Fe and Cl K-edges (μXANES) reveal the correlation between the valence distribution in the corrosion products and the evolution of the chloride concentration. In addition to the presence of the well-known iron oxyhydroxide β-FeOOH: akaganeite, we highlight the presence of another important phase, the β-Fe2(OH)3Clhydroxychloride. These important findings help to gain new insights concerning the influence of such phases in the iron corrosion mechanism within their precise characterization. (orig.)

  1. Investigation of the CH3Cl + CN− reaction in water: Multilevel quantum mechanics/molecular mechanics study

    International Nuclear Information System (INIS)

    The CH3Cl + CN− reaction in water was studied using a multilevel quantum mechanics/molecular mechanics (MM) method with the multilevels, electrostatic potential, density functional theory (DFT) and coupled-cluster single double triple (CCSD(T)), for the solute region. The detailed, back-side attack SN2 reaction mechanism was mapped along the reaction pathway. The potentials of mean force were calculated under both the DFT and CCSD(T) levels for the reaction region. The CCSD(T)/MM level of theory presents a free energy activation barrier height at 20.3 kcal/mol, which agrees very well with the experiment value at 21.6 kcal/mol. The results show that the aqueous solution has a dominant role in shaping the potential of mean force. The solvation effect and the polarization effect together increase the activation barrier height by ∼11.4 kcal/mol: the solvation effect plays a major role by providing about 75% of the contribution, while polarization effect only contributes 25% to the activation barrier height. Our calculated potential of mean force under the CCSD(T)/MM also has a good agreement with the one estimated using data from previous gas-phase studies

  2. An Investigation for Anti-Stress Corrosion Cracking of SUS 304 Stainless Steel in MgCl2 Boiling Solution

    International Nuclear Information System (INIS)

    The anti-stress corrosion cracking method by current density of cathodic protection was studied for the stress corrosion cracking of SUS304 austenitic stainless steel in the environment of 42% MgCl2 boiling solution. The correlation between the critical current density for anti-stress corrosion cracking and the initial crack intensity factor was inspected in the base metal and the welding heat affected zone. Main results obtained are as follows: 1. The critical initial crack intensity factor KIiSCC can be controlled by the current density of cathodic protection. 2. The correlation between the critical current density of cathodic protection for anti-stress corrosion cracking i (μA/cm2) and the initial crack intensity factor KIi (kg. mm-3/2) is illustrated by the following formulas. In base metal : i= 0.0689 KIi - 0.238 In heat affected zone : i=0.0724 KIi - 4.8353 3. In condition of additional below the critical current density of cathodic protection for anti-stress corrosion cracking, the stress corrosion cracking is appeared to be inter-granual fracture

  3. Experimental and theoretical investigation of semiconductor optical amplifier (SOA) based all-optical switches

    DEFF Research Database (Denmark)

    Nielsen, Mads Lønstrup

    2004-01-01

    found to limit the performance. Two implementations of differential-mode switches, the Mach Zehnder interferometer (MZI) and the delayed-interferometer signal converter (DISC), are compared at bitrates up to 160 Gb/s, and fundamental differences in terms of noise filtering are demonstrated. The DISC...... coupler is verified, also at 10 Gb/s. 3R regeneration (2R + re-timing), based on a cross-gain modulation wavelength converter and a MZI, is demonstrated at 40 Gb/s in a recirculating loop experiment over 4000 km. Moreover, an optical subsystem for NRZ clock recovery, based on self-phase modulation and...... experimentally with MZIs, at 20 Gb/s and 10 Gb/s, respectively, whereas combinations of Boolean functions in MZIs are used to demonstrate a 3-input XOR gate, a data segment bit comparator, and a compact parity checking scheme, all at 10 Gb/s....

  4. Experimental investigation on the magneto-optic effects of ferrofluids via dynamic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Jamon, D. [Laboratory DIOM, Universite Jean Monnet, 23 rue du Dr Paul Michelon, 42023 Saint-Etienne Cedex 2 (France); Donatini, F. [Institut Neel, CNRS et Universite Joseph Fourier, BP 166, F-38042 Grenoble Cedex 9 (France); Siblini, A. [Laboratory DIOM, Universite Jean Monnet, 23 rue du Dr Paul Michelon, 42023 Saint-Etienne Cedex 2 (France); Royer, F. [Laboratory DIOM, Universite Jean Monnet, 23 rue du Dr Paul Michelon, 42023 Saint-Etienne Cedex 2 (France)], E-mail: Francois.Royer@univ-st-etienne.fr; Perzynski, R.; Cabuil, V.; Neveu, S. [LI2C, UMR 7612, Universite P and M Curie, 4 place Jussieu, 75252 Paris Cedex 05 (France)

    2009-05-15

    An experimental investigation on the origin of the magneto-optic effects of ferrofluids is presented. Dynamic measurements of their transverse and longitudinal magneto-optic effects and their magnetic properties have been performed. As ferrofluids are colloidal suspensions of magnetic particles in a liquid, the influence of two parameters has been studied: the magnetic anisotropy energy of particles and the carrier liquid viscosity for four ferrofluid samples. The interpretation and the comparison of results give some clues for a better understanding of magneto-optical effects of ferrofluids.

  5. Experimental investigation on the magneto-optic effects of ferrofluids via dynamic measurements

    International Nuclear Information System (INIS)

    An experimental investigation on the origin of the magneto-optic effects of ferrofluids is presented. Dynamic measurements of their transverse and longitudinal magneto-optic effects and their magnetic properties have been performed. As ferrofluids are colloidal suspensions of magnetic particles in a liquid, the influence of two parameters has been studied: the magnetic anisotropy energy of particles and the carrier liquid viscosity for four ferrofluid samples. The interpretation and the comparison of results give some clues for a better understanding of magneto-optical effects of ferrofluids

  6. Theoretical investigation of TbNi_{5-x}Cu_x optical properties

    OpenAIRE

    Nekrasov, I. A.; Kokorina, E.E.; ~Galkin, V. A.; Kuz'min, Y. I.; ~Knyazev, Y. V.; Kuchin, A. G.

    2010-01-01

    In this paper we present theoretical investigation of optical conductivity for intermetallic TbNi_{5-x}Cu_x series. In the frame of LSDA+U calculations electronic structure for x=0,1,2 and on top of that optical conductivities were calculated. Disorder effects of Ni for Cu substitution on a level of LSDA+U densities of states (DOS) were taken into account via averaging over all possible Cu ion positions for given doping level x. Gradual suppression and loosing of structure of optical conducti...

  7. Spectroscopic ellipsometry investigations of optical anisotropy in obliquely deposited hafnia thin films

    Science.gov (United States)

    Tokas, R. B.; Jena, Shuvendu; Haque, S. Maidul; Rao, K. Divakar; Thakur, S.; Sahoo, N. K.

    2016-05-01

    In present work, HfO2 thin films have been deposited at various oblique incidences on Si substrates by electron beam evaporation. These refractory oxide films exhibited anisotropy in refractive index predictably due to special columnar microstructure. Spectroscopic ellipsometry being a powerful tool for optical characterization has been employed to investigate optical anisotropy. It was observed that the film deposited at glancing angle (80°) exhibits the highest optical anisotropy. Further, anisotropy was noticed to decrease with lower values of deposition angles while effective refractive index depicts opposite trend. Variation in refractive index and anisotropy has been explained in light of atomic shadowing during growth of thin films at oblique angles.

  8. Structural, electronic and optical properties of Cu-doped ZnO: experimental and theoretical investigation

    Science.gov (United States)

    Horzum, S.; Torun, E.; Serin, T.; Peeters, F. M.

    2016-06-01

    Experiments are supplemented with ab initio density functional theory (DFT) calculations in order to investigate how the structural, electronic and optical properties of zinc oxide (ZnO) thin films are modified upon Cu doping. Changes in characteristic properties of doped thin films, that are deposited on a glass substrate by sol-gel dip coating technique, are monitored using X-ray diffraction (XRD) and UV measurements. Our ab initio calculations show that the electronic structure of ZnO can be well described by DFT+U/? method and we find that Cu atom substitutional doping in ZnO is the most favourable case. Our XRD measurements reveal that the crystallite size of the films decrease with increasing Cu doping. Moreover, we determine the optical constants such as refractive index, extinction coefficient, optical dielectric function and optical energy band gap values of the films by means of UV-Vis transmittance spectra. The optical band gap of ZnO the thin film linearly decreases from 3.25 to 3.20 eV at 5% doping. In addition, our calculations reveal that the electronic defect states that stem from Cu atoms are not optically active and the optical band gap is determined by the ZnO band edges. Experimentally observed structural and optical results are in good agreement with our theoretical results.

  9. Unsteady Computational and Experimental Fluid Dynamics Investigations of Aerodynamic Loads of Large Optical Telescopes

    OpenAIRE

    Mamou, Mahmoud; Mébarki, Youssef; Tahi, Ali

    2010-01-01

    The importance of applying computational fluid dynamics (CFD) for large optical telescope flow analyses in the early design phase was emphasized and some critical challenges for accurate flow field prediction were drawn. Also, a thorough literature review was performed specifically on the role of CFD that can play towards accurate prediction of pressure loads on telescopes structure. Some recent CFD and experimental investigations, on a scaled model of a very large optical telescope housed wi...

  10. AN INVESTIGATION ON THE EFFECTS OF ELECTRICAL CHARACTERISTICS ON OPTICAL CHARACTERISTICS OF LED

    OpenAIRE

    Erdem ÖZÜTÜRK

    2006-01-01

    In this study, the effects of electrical characteristics on optical characteristics of LED have been investigated. These effects between them have been occured via heat. LED radiant power is proportional with LED current and inverse proportional with junction temperature. Increasing the current of LED causes increasing radiant power and power dissipation of LED. The power-current and instantaneous resistance-current variations have important effect on the radiant power- current optical charac...

  11. Investigation of the evaporation process conditions on the optical constants of zirconia films

    International Nuclear Information System (INIS)

    Deposition parameters required for producing zirconia films for use in optical multilayer systems by electron-beam gun evaporation of zirconia and zirconium starting materials were investigated. The optical constants were determined as a function of distance, partial pressure of oxygen, and angle of incidence. The direct and reactive evaporation processes yielded ZrO2 films with refractive indices of 2.08 and 2.14, respectively, for vapor incident on the substrate at normal incidence

  12. Software and Hardware System for the Investigation of the Thin Film Optical Properties

    Directory of Open Access Journals (Sweden)

    O.V. Fedchenko

    2012-06-01

    Full Text Available Using Torhlabs optical elements and graphic software development system LabVIEW 2010 the software and hardware automation system for the investigation of the optical properties of multilayer film systems was built. The joint genetic algorithm was suggested to process experimental data of Null-ellipsometry and X-ray reflectometry. It was shown that the proposed technique lets one simulate phase transitions, diffusion processes and interface blurring in multilayer film systems very accurate for different computational theoretic models.

  13. Software and Hardware System for the Investigation of the Thin Film Optical Properties

    OpenAIRE

    O.V. Fedchenko; K.V. Tyschenko; S.I. Protsenko; M.G. Demydenko

    2012-01-01

    Using Torhlabs optical elements and graphic software development system LabVIEW 2010 the software and hardware automation system for the investigation of the optical properties of multilayer film systems was built. The joint genetic algorithm was suggested to process experimental data of Null-ellipsometry and X-ray reflectometry. It was shown that the proposed technique lets one simulate phase transitions, diffusion processes and interface blurring in multilayer film systems very accurate for...

  14. Simulation of continuously logical ADC (CL ADC) of photocurrents as a basic cell of image processor and multichannel optical sensor systems

    Science.gov (United States)

    Krasilenko, Vladimir G.; Nikolskyy, Aleksandr I.; Lazarev, Alexander A.; Krasilenko, Oksana V.; Krasilenko, Irina A.

    2013-05-01

    The paper considers results of design and modeling of continuously logical analog-to-digital converters (ADC) based on current mirrors for image processor and multichannel optical sensor systems with parallel inputs-outputs. For such multichannel serial-parallel analog-to-digital converters (SP ADC) it is needed base photoelectron cells, which are considered in paper. Its have a number of advantages: high speed and reliability, simplicity, small power consumption, high integration level for linear and matrix structures. We show design of the continuously logical ADC of photocurrents and its base digit cells (ABC) and its simulations. We consider CL ADC for Gray and binary codes. Each channel of the structure consists of several base digit cells (ABC) on 20-30 CMOS FETs and one photodiode. The supply voltage of the ABC is 1-3.3V, the range of an input photocurrent is 0.1 - 10μA, the transformation time is 30ns at 5-8 bit binary or Gray codes, power consumption is about 1mW. One channel of ADC with iteration is based on one ABC-3(G) and SHD, and it has only 40 CMOS transistors. The general power consumption of the ADC, in this case, is only 50-100μW, if the maximum input current is 1μA. The CL ADC opens new prospects for realization of linear and matrix image processor and photo-electronic structures with picture operands, which are necessary for neural networks, digital optoelectronic processors, neural-fuzzy controllers, and so forth.

  15. Depassivation-repassivation behavior of type-312L stainless steel in NaCl solution investigated by the micro-indentation

    International Nuclear Information System (INIS)

    Repassivation behavior of type-312L stainless steel containing 6% of molybdenum was examined in NaCl solution using in situ micro-indentation technique, together with type-304 and 316L stainless steels. High stability of the passive film formed on the type-312L stainless steel was also examined by depth profiling analysis of passive films using glow discharge optical emission spectroscopy (GDOES). In 0.9 mol dm-3 NaCl solution at 296 K the type-304 and 316L stainless steels are passive only up to 0.3 V (SHE), above which pitting corrosion occurs. In contrast, no pitting corrosion occurs on type-312L stainless steel. Despite the significant difference of the pitting corrosion resistance, the repassivation kinetics of the three stainless steels, examined by micro-indentation at 0.3 V (SHE), is similar. The presence of molybdenum in the stainless steel does not influence the repassivation kinetics. The charge required to repassivate the ruptured type-312L stainless steel surface increases approximately linearly with the potential, even though the passivity-maintaining current increased markedly at potentials close to the transpassive region. Repassivation occurs without accompanying significant dissolution of steel, regardless of the stability of passive state. Depth profiling analyses of the passive films on the type-312L stainless steels formed at several potentials revealed that molybdenum species enrich in the outer layer of the passive film, below which chromium-enriched layer is present. The permeation of chloride ions may be impeded by the outer layer containing molybdate, enhancing the resistance against the localized corrosion of the type-312L stainless steel.

  16. Experimental setup for investigation of nanoclusters at cryogenic temperatures by electron spin resonance and optical spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Mao, S., E-mail: maoshunghost@tamu.edu; Meraki, A.; McColgan, P. T.; Khmelenko, V. V.; Lee, D. M. [Institute for Quantum Science and Engineering and Department of Physics and Astronomy, Texas A and M University, College Station, Texas 77843 (United States); Shemelin, V. [Cornell Laboratory for Accelerator-based Science and Education, Cornell University, Ithaca, New York 14853 (United States)

    2014-07-15

    We present the design and performance of an experimental setup for simultaneous electron spin resonance (ESR) and optical studies of nanoclusters with stabilized free radicals at cryogenic temperatures. A gas mixture of impurities and helium after passing through a RF discharge for dissociation of molecules is directed onto the surface of superfluid helium to form the nanoclusters of impurities. A specially designed ESR cavity operated in the TE{sub 011} mode allows optical access to the sample. The cavity is incorporated into a homemade insert which is placed inside a variable temperature insert of a Janis {sup 4}He cryostat. The temperature range for sample investigation is 1.25–300 K. A Bruker EPR 300E and Andor 500i optical spectrograph incorporated with a Newton EMCCD camera are used for ESR and optical registration, respectively. The current experimental system makes it possible to study the ESR and optical spectra of impurity-helium condensates simultaneously. The setup allows a broad range of research at low temperatures including optically detected magnetic resonance, studies of chemical processes of the active species produced by photolysis in solid matrices, and investigations of nanoclusters produced by laser ablation in superfluid helium.

  17. Phase transitions in [Co(NH{sub 3}){sub 6}](ClO{sub 4}){sub 3} investigated by neutron scattering methods

    Energy Technology Data Exchange (ETDEWEB)

    Hetmańczyk, Łukasz, E-mail: hetmancz@chemia.uj.edu.pl [Phase Transitions Research Team, Department of Chemical Physics, Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków (Poland); Frank Laboratory of Neutron Physics, JINR, Dubna 141980 (Russian Federation); Górska, Natalia [Research Center for Structural Thermodynamics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Hetmańczyk, Joanna [Phase Transitions Research Team, Department of Chemical Physics, Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków (Poland); Frank Laboratory of Neutron Physics, JINR, Dubna 141980 (Russian Federation); Mikuli, Edward [Phase Transitions Research Team, Department of Chemical Physics, Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków (Poland); Natkaniec, Ireneusz [Frank Laboratory of Neutron Physics, JINR, Dubna 141980 (Russian Federation); Department of Radiospectroscopy, Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland)

    2013-02-01

    Highlights: ► Structure and molecular reorientations in [Co(NH{sub 3}){sub 6}](ClO{sub 4}){sub 3} at phase transitions. ► IR, RS, IINS spectra calculated by DFT show good agreement with experimental data. ► High temperature phase is dynamically orientationally disordered crystal phase. ► Excess of elasticity in QENS below T{sub C3} is observed. ► Crystal structure does not change drastically at the phase transition. - Abstract: [Co(NH{sub 3}){sub 6}](ClO{sub 4}){sub 3} was investigated by neutron scattering methods in the temperature range of 20–290 K. Neutron powder diffraction revealed that the crystal structure does not change at the T{sub C2} and T{sub C3} phase transitions. High temperature phases are orientationally disordered. QENS study showed that NH{sub 3} ligands perform rapid reorientational motion around their 3-fold axes in a wide temperature range. However, below T{sub C3} some excess of elastic scattering is observed, which can be explained by the assumption that only half of the NH{sub 3} groups reorient fast enough to contribute to the QENS broadening, whereas the remaining NH{sub 3} groups reorient more slowly. The activation energy for NH{sub 3} jumps, estimated from the temperature dependence of QENS broadening, is small but comparable with the results obtained for other hexaammine complexes. Quantum chemical calculation, carried out on the basis of DFT for isolated [Co(NH{sub 3}){sub 6}]{sup 3+} cation and ClO{sub 4}{sup -} anion, and experimental (IR, RS, IINS) spectra are in good agreement.

  18. EIS and XPS investigations on the corrosion mechanism of ternary Zn-Co-Mo alloy coatings in NaCl solution

    Science.gov (United States)

    Winiarski, J.; Tylus, W.; Szczygieł, B.

    2016-02-01

    The changes in composition of the corrosion products of electrodeposited ternary Zn-Co-Mo alloy coatings on AISI 1015 steel during exposure to 0.5 mol dm-3 NaCl solution were investigated. XPS studies demonstrated that at the initial stage of corrosion on the surface of Zn-Co-Mo coating zinc hydroxide layer is formed. Hydroxyl groups react with chloride and carbonate ions which lead to the formation of zinc hydroxy carbonates and zinc hydroxy chlorides. The share of these compounds in the oxidation products is initially large. However, with time zinc hydroxy compounds slowly changes to zinc oxide, which is more stable corrosion product. It was estimated that after 24 h of exposure to NaCl solution nearly 60% of zinc detected on the surface of Zn-Co-Mo coating was present in the ZnO form, 18% in the form of zinc hydroxy chloride, and more than 21% as zinc hydroxy carbonate. XPS analyses revealed that the amount of zinc hydroxy chloride increases as the exposure time lengthens and it is significantly higher than at the surface of binary Zn-Co coating. The presence of crystalline zinc chloride hydroxide as a stable product of corrosion of ternary Zn-Co-Mo alloy coating in a 0.5 mol dm-3 NaCl solution was confirmed by XRD analysis. According to XRD and FTIR other zinc corrosion products like: ZnO, Zn(OH)2 and Zn5(CO3)2(OH)6 were also present. The results of XPS and EIS measurements allow us to assume that in the presence of Mo in the alloy, on the surface of ternary Zn-Co-Mo alloy (3.4 wt.% Co, 2.7 wt.% Mo) coating more zinc hydroxy chloride is formed, which favors higher corrosion resistance of this coating.

  19. Optical investigations and control of spindynamics in Mn doped II-VI quantum dots

    International Nuclear Information System (INIS)

    The present thesis deals with the spin of charge carriers confined in CdSe/ZnSe quantum dots (QDs) closely linked to the polarization of emitted photons. II-VI material systems can be adequately mixed with the B-group element manganese. Such semimagnetic nanostructures offer a number of characteristic optical and electronic features. This is caused by an exchange interaction between the spin of optically excited carriers and the 3d electrons of the Mn ions. Within the framework of this thesis addressing of well defined spin states was realized by optical excitation of charge carriers. The occupation of different spin states was detected by the degree of polarization of the emitted photoluminescence (PL) light. For that purpose different optical methods of time-resolved and time-integrated spectroscopy as well as investigations in magnetic fields were applied. (orig.)

  20. Frontiers of Optical Spectroscopy Investigating Extreme Physical Conditions with Advanced Optical Techniques

    CERN Document Server

    Bartolo, Baldassare

    2005-01-01

    Advanced spectroscopic techniques allow the probing of very small systems and very fast phenomena, conditions that can be considered "extreme" at the present status of our experimentation and knowledge. Quantum dots, nanocrystals and single molecules are examples of the former and events on the femtosecond scale examples of the latter. The purpose of this book is to examine the realm of phenomena of such extreme type and the techniques that permit their investigations. Each author has developed a coherent section of the program starting at a somewhat fundamental level and ultimately reaching the frontier of knowledge in the field in a systematic and didactic fashion. The formal lectures are complemented by additional seminars.

  1. The use of the nonlinear optical loop mirror for investigations of pulse breakup in optical fibers

    Science.gov (United States)

    Kuzin, Evgeny A.; Pottiez, Olivier; Ibarra-Escamilla, Baldemar

    2011-03-01

    Pulse breakup and the formation of a bunch of solitons are the principal processes at the initial stage of the supercontinuum generation using long pulses for pumping. Most investigations use the measurement of the output spectrum to characterize the development of the supercontinuum. The extraction of an individual soliton or a group of solitons with similar parameters from the bunch can reveal details that are usually hidden when only the output spectrum is measured. Earlier we have studied the NOLM including a twisted fiber and a quarter wave retarder (QWR) in the loop. Its operation is based on the nonlinear polarization rotation effect. We showed that this NOLM is stable to changes of environmental conditions, and allows simple and predictable changes of its characteristics. In previous works we demonstrated its application for mode-locked lasers, pedestal suppression, or retrieval of a pulse shape. In this work we demonstrate that the NOLM is a viable device for the investigation of pulse breakup process and soliton formation. The operation principle is based on the fact that the NOLM has a maximum transmission for the solitons with specific durations while solitons with shorter and longer durations are strongly rejected. The duration associated with high transmission depends on the NOLM length and can also be changed by amplification of the solitons before entering the NOLM. By an appropriate choice of the NOLM parameters and the amplification of the bunch of solitons, the extraction of the solitons with selected parameters is possible.

  2. Synthesis, structural investigation and thermal properties of a novel manganese complex Mn2(DAT)2Cl4(H2O)4 (DAT = 1,5-diaminotetrazole)

    International Nuclear Information System (INIS)

    A novel manganese complex Mn2(DAT)2Cl4(H2O)4, where DAT is 1,5-diaminotetrazole, was synthesized by the reaction of manganese(II) chloride tetrahydrate and 1,5-diaminotetrazole (DAT) in ethanol, and characterized by elemental analysis, FT-IR spectroscopy. The crystal structure was determined through X-ray single crystal diffraction. The molecular unit of Mn2(DAT)2Cl4(H2O)4 has a distorted octahedral structure, containing two central manganese cations, which coordinated by a mono-dentate terminal chloride, a bulky DAT ligand and two water molecules, and linked by two bidentate bridging chloride ligands. There are two main exothermic peaks and one endothermic peak in the thermal decomposition process, investigated by differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA), the final residue of the title compound at 600 deg. C is MnO. The kinetic parameters of the endothermic process and two main exothermic processes were studied by applying the Kissinger's and Ozawa-Doyle's methods.

  3. Investigation of bending loss in a single-mode optical fibre

    Indian Academy of Sciences (India)

    A Zendehnam; M Mirzaei; A Farashiani; L Horabadi Farahani

    2010-04-01

    Loss of optical power in a single-mode optical fibre due to bending has been investigated for a wavelength of 1550 nm. In this experiment, the effects of bending radius (4–15 mm, with steps of 1 mm), and wrapping turns (up to 40 turns) on loss have been studied. Twisting the optical fibre and its influence on power loss also have been investigated. Variations of bending loss with these two parameters have been measured, loss with number of turns and radius of curvature have been measured, and with the help of computer curve fitting method, semi-empirical relationships between bending loss and these two parameters have been found, which show good agreement with the obtained experimental results.

  4. Investigations into the endogenic abcisinic acid and cytokinin content of soja bean cultures with varying salt sensitivity, as well as into the effect of exogenically applied abcisinic acid to the Cl--translocation

    International Nuclear Information System (INIS)

    Two soja bean cultures with different Cl- sensitivity the 'Lee' and 'Jackson' were used for the investigation. Salting of the growth medium with 75 nM NaCl massively increased the obcisinic acid (ABA) concentration in the leaves, not however of the cytokinin content. The high ABA concentrations remained in the 'Jackson' sort even after a 7-day salt treatment. The moderately salt-resistant sort 'Lee' had a remarkable Cl- retention mechanism. The addition of 10-5 and 10-6 M ABA to the growth medium reduced the Cl- concentration in the sprout and simultaneously increased the accumulation in the root. This ABA effect failed at high salt concentration. The order of magnitude in which ABA is taken up from a normal or salted growth medium and its distribution were investigated using 14C. Macroautoradiographic investigations show that after 35 h the whole sprout is radioactively labelled whereby a prefered accumulation is found in youngest part of the sprout. The highest Cl- values were found in the older leaves. The ABA is obviously transported to the stomata with the transpiration flow and inhibits the transpiration by its effect on the stomata. Subjecting the soja beans to a 75 mM NaCl concentration, can lead to a decrease of transpiration due to the strong salt concentration. The addition of ABA as well had an inhibiting effect on the water release of the plants without influencing the Cl- translocation. (MG)

  5. Investigation of Microopto-eletromechanical Angular Velocity and Acceleration Transducers based on Optical Tunneling Effect

    Science.gov (United States)

    Busurin, V. I.; Lwin, Naing Htoo; Tuan, Pham Anh

    In this paper the possibility of microopto-electromechanical (MOEM) angular velocity and acceleration transducers based on optical tunneling effect (OTE) is considered. The generalized model of MOEM transducers with various types of sensing elements (SE) is developed, transfer functions are investigated, and the errors with various design parameters of transducers are estimated.

  6. Investigation of near-collinear degenerated quasi-phase matching optical parametric amplification using PPKTP crystal

    Institute of Scientific and Technical Information of China (English)

    Baozhen Zhao; Xiaoyan Liang; Yuxin Leng; Cheng Wang; Juan Du; Zhengquan Zhang; Zhizhan Xu

    2005-01-01

    The gain properties of near-collinear degenerated phase-matched optical parametric amplification (OPA) using PPKTP crystal are investigated theoretically. The results indicate that the type-0 phase matching of PPKTP has larger accepted angle and better gain spectrum by tuning crystal temperature or rotating crystal angle.

  7. Investigation of a Novel Optical Phase Demodulator based on Sampling Phase-Locked Loop

    DEFF Research Database (Denmark)

    Zibar, Darko; Johansson, L.A.; Chou, H.F.; Ramaswamy, A.; Rodwell, M.; Bowers, J.E.

    A novel phase-locked coherent demodulator, based on a sampling phase-locked loop, is presented and investigated theoretically. The demodulator is capable of operating at high-frequencies, by using optical sampling to downconvert the high-frequency input RF signal to the frequency range of the bas...

  8. Investigation on a replica step gauge for optical 3D scanning of micro parts

    DEFF Research Database (Denmark)

    Cantatore, Angela; De Chiffre, Leonardo; Carmignato, S.

    2010-01-01

    . The stability over time of the step gauge was evaluated by repetitive measurement campaigns over a period of eight months, using measurements taken with a tactile CMM and with an optical scanner. Surface cooperativeness was investigated by measuring artefact grooves and pitch and comparing results...

  9. Investigation of DBS electro-oxidation reaction in the aqueous-organic solution of LiClO4

    International Nuclear Information System (INIS)

    A process of dibutyl sulphide (DBS) electro-oxidation using electrolysis and cyclic voltamperometry was investigated in water-methanol solution using different electrodes (platinum, boron doped diamond, graphite and glassy carbon). Obtained results indicate that the DBS electro-oxidation process is irreversible in voltamperometric conditions. It was shown that during DBS electrolytic oxidation on Pt, at the low anode potential (1.8 V), DBS was oxidized to sulphoxide and sulphone. Electrolysis at higher potential (up to 3.0 V) resulted in complete DBS oxidation and formation of various products, including: butyric acid, sulphuric acid, butanesulphinic acid, butanesulphonic acid, identified using gas chromatography (GC-AED) and mass spectrometry (GC-MS) methods.

  10. Preliminary investigations of rat skin after topical application of optical clearing agent

    Science.gov (United States)

    Wang, Jing; Zhu, Dan

    2011-03-01

    The tissue optical clearing technique based on immersion of tissues into optical clearing agents (OCAs) can enhance the penetration depth of light in tissues, thus improve the capabilities of noninvasive optical diagnosis and therapeutic treatment. However, the optical clearing efficiency of skin caused by topical application of OCAs usually suffers from the barrier of stratum corneum and epithelium. The addition of chemical penetration enhancers to OCAs could significantly improve the optical clearing of skin, but the investigations on their safety are seldom concerned. In this study, based on the direct observation and histological examinations, the short-term and long-term effects of the mixture of PEG-400 and Thiazone on morphology and microstructure of in vivo rat skin were investigated. The results demonstrated that, in the first week, the hair growth was stunted, some degree of abnormal thickens and vacuoles occurred at the epidermis layer, and the collagen arranged denser. After 2 week, the morphology and microstructure of rat skin was completely recovered. It means that there is no long-term effect on rat skin by the mixture of PEG-400 and Thiazone. In addition, this work provides a useful method for assessing the safety of OCAs to skin.

  11. Inelastic Incoherent Neutron Scattering Investigation of Lattice Dynamics of [N(C_{2}H_{5})_{4}]_{2}MeCl_{4} (Me=Zn,Cu) Compound

    CERN Document Server

    Kazimirov, V Yu; Tylczynski, Z

    2001-01-01

    Generalized phonon densities of states of polycrystalline samples of [N(C_{2}H_{5})_{4}]_{2}MeCl_{4} (Me=Zn,Cu) in a wide temperatures range higher and below phase transitions points were investigated by inelastic incoherent neutron scattering. The character of change of phonon densities with temperature allows us to make some conclusions about a nature of observed phase transitions. In particular, since inelastic incoherent scattering is most sensitive to vibrations of protons, it is possible to conclude, that decrease of temperature leads to ordering protons of a C_{2}H_{5} radical, and, apparently, [N(C_{2}H_{5})_{4}]^{+} cation as whole. In result, rotary diffusion of molecular complexes of crystal transforms into librations with decrease of temperature and appropriate lowering of symmetry.

  12. Investigation of the screen optics of thick CsI(Tl) detectors

    Science.gov (United States)

    Howansky, Adrian; Peng, Boyu; Suzuki, Katsuhiko; Yamashita, Masanori; Lubinsky, A. R.; Zhao, Wei

    2015-03-01

    Flat panel imagers (FPI) are becoming the dominant detector technology for digital x-ray imaging. In indirect FPI, the scintillator that provides the highest image quality is Thallium (Tl) doped Cesium Iodide (CsI) with columnar structure. The maximum CsI thickness used in existing FPI is ~600 microns, due to concerns of loss in spatial resolution and light output with further increase in thickness. The goal of the present work is to investigate the screen-optics for CsI with thicknesses much larger than that used in existing FPI, so that the knowledge can be used to improve imaging performance in dose sensitive and higher energy applications, such as cone-beam CT (CBCT). Columnar CsI(Tl) scintillators up to 1 mm in thickness with different screen-optical design were investigated experimentally. Pulse height spectra (PHS) were measured to determine the Swank factor at x-ray energies between 25 and 75 keV, and to derive depth-dependent light escape efficiency i.e. gain. Detector presampling MTF, NPS and DQE were measured using a high-resolution CMOS optical sensor. Optical Monte Carlo simulation was performed to estimate optical parameters for each screen design and derive depth-dependent gain and MTF, from which overall MTF and DQE were calculated and compared with measured results. The depth-dependent imaging performance parameters were then used in a cascaded linear system model (CLSM) to investigate detector performance under screen- and sensor-side irradiation conditions. The methodology developed for understanding the optics of thick CsI(Tl) will lead to detector optimization in CBCT.

  13. Investigation of Power8 processors for astronomical adaptive optics real-time control

    CERN Document Server

    Basden, Alastair

    2015-01-01

    The forthcoming Extremely Large Telescopes all require adaptive optics systems for their successful operation. The real-time control for these systems becomes computationally challenging, in part limited by the memory bandwidths required for wavefront reconstruction. We investigate new POWER8 processor technologies applied to the problem of real-time control for adaptive optics. These processors have a large memory bandwidth, and we show that they are suitable for operation of first-light ELT instrumentation, and propose some potential real-time control system designs. A CPU-based real-time control system significantly reduces complexity, improves maintainability, and leads to increased longevity for the real-time control system.

  14. Investigation of patterning effects in ultrafast SOA-based optical switches

    DEFF Research Database (Denmark)

    Xu, Jing; Zhang, Xinliang; Mørk, Jesper

    2010-01-01

    Ultrafast optical switching employing semiconductor optical amplifier (SOA) based optical switches has been demonstrated at bitrates up to 640 Gbit/s. However, patterning effects caused by relatively slow recovery processes in semiconductor structures remain as an important deteriorating factor...... that limits the ultimate speed at which SOA-based switches can be operated. In this paper, we investigate the patterning effects of SOA-based switches using a systematic approach. A simple condition for the lower bound limit of the bit pattern length that should be adopted in the performance...... evaluations of the switches is derived. It is shown that the minimum bit pattern length scales linearly with the bitrate and the recovery time of the SOA. To overcome the excessive computation time needed for numerical analysis at long pseudorandom binary sequence (PRBS) lengths, an effective method, i...

  15. Investigation on optical absorption properties of ion irradiated single walled carbon nanotubes

    International Nuclear Information System (INIS)

    In the present study change in the optical absorption properties of single walled carbon nanotubes (SWCNTs) under nickel ion (60 MeV) irradiation at various fluences has been investigated. Langmuir Blodgett technique is used to deposit SWCNT thin film of uniform thickness. AFM analysis shows a network of interconnected bundles of nanotubes. UV-Vis-NIR absorption spectra indicate that the sample mainly contain SWCNTs of semiconducting nature. It has been found in absorption spectra that there is decrease in the intensity of the characteristic SWCNT peaks with increase in fluence. At fluence value 1×1014 ions/cm2 there is almost complete suppression of the characteristic SWCNTs peaks.The decrease in the optical absorption with increase in fluence is due to the increase in the disorder in the system which leads to the decrease in optically active states

  16. Investigation on optical absorption properties of ion irradiated single walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Vishalli,, E-mail: vishalli-2008@yahoo.com; Dharamvir, Keya, E-mail: keya@pu.ac.in [Department of Physics, Panjab University, Chandigarh (India); Kaur, Ramneek; Raina, K. K. [Materials Research Laboratory, School of Physics and Materials Science, Thapar University, Patiala (India); Avasthi, D. K. [Materials Science Group, Inter University Accelerator Centre, ArunaAsaf Ali Marg, NewDelhi (India); Jeet, Kiran [Electron Microscopy and Nanoscience laboratory, Punjab Agriculture University, Ludhiana (India)

    2015-08-28

    In the present study change in the optical absorption properties of single walled carbon nanotubes (SWCNTs) under nickel ion (60 MeV) irradiation at various fluences has been investigated. Langmuir Blodgett technique is used to deposit SWCNT thin film of uniform thickness. AFM analysis shows a network of interconnected bundles of nanotubes. UV-Vis-NIR absorption spectra indicate that the sample mainly contain SWCNTs of semiconducting nature. It has been found in absorption spectra that there is decrease in the intensity of the characteristic SWCNT peaks with increase in fluence. At fluence value 1×10{sup 14} ions/cm{sup 2} there is almost complete suppression of the characteristic SWCNTs peaks.The decrease in the optical absorption with increase in fluence is due to the increase in the disorder in the system which leads to the decrease in optically active states.

  17. Investigating the use of the acousto-optic effect for acoustic holography

    DEFF Research Database (Denmark)

    Torras Rosell, Antoni; Fernandez Grande, Efren; Jacobsen, Finn; Barrera Figueroa, Salvador

    2012-01-01

    Recent studies have demonstrated that the acousto-optic effect, that is, the interaction between sound and light, can be used as a means to visualize acoustic fields in the audible frequency range. The changes of density caused by sound waves propagating in air induce phase shifts to a laser beam...... that travels through the acoustic field. This phenomenon can in practice be captured with a laser Doppler vibrometer (LDV), and the pressure distribution of the acoustic field can be reconstructed using tomography. The present work investigates the potential of the acousto-optic effect in acoustic...... holography. Two different holographic methods are examined for this purpose. One method first reconstructs the hologram plane using acousto-optic tomography and then propagates it using conventional near-field acoustic holography (NAH). The other method exploits the so-called Fourier Slice Theorem and bases...

  18. Numerical investigation on CO2 photocatalytic reduction in optical fiber monolith reactor

    International Nuclear Information System (INIS)

    Highlights: ► Methanol resultant versus vapor ratio, inlet velocity and light intensity are studied. ► Effect of optical fiber deviation on the methanol concentration is presented. ► Methanol concentration increases as the vapor ratio and light intensity increase. ► It decreases with increasing the inflow velocity. ► With increasing optical fiber deviation, methanol production efficiency decreases. - Abstract: Photocatalytic reduction of carbon dioxide had been a promising way to control greenhouse gas emission. Optical fiber monolith reactor with catalyst coated on the inner surface attracts attention in recent years by its high light utilization ratio. A two-dimensional computational model to describe the photocatalytic reduction of carbon dioxide in a multichannel optical fiber monolith reactor, which had been experimentally investigated, is developed and simulated. Laminar fluid flow, empirical radiation field and a Langmuir–Hinshelwood kinetics submodel are incorporated in this model, which numerical results agree well with the experimental data. The variation of methanol concentration distribution with the inflow water vapor concentration ratio, inflow velocity and light intensity input are obtained and analyzed. The influence of the deviation of optical fiber installed in the monolith upon the methanol concentration and production efficiency is presented. The results show that the methanol concentration at outlet increases as the inflow water vapor concentration ratio and light intensity input increase, but decreases with increasing the inflow velocity, all of which cause the rise of overall methanol production. With the increase of the optical fiber deviation from the monolith axis, the methanol production efficiency will decrease. Central and straight installation of the optical fiber is recommended either in experiments or scale-up photocatalytic industries.

  19. Investigation of the microstructure of coatings for high power lasers by non-optical techniques

    International Nuclear Information System (INIS)

    The microstructure of optical coatings strongly influence their resistance to high fluence laser, scatter properties, as well as, their mechanical and environmental stability. The relative merits of non-optical techniques, such as: scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and focused ion beam, are discussed as they apply to optical multilayer coatings. The combination of these techniques provides a unique method to analyze defects in coatings. The long term objective of this work is to: understand the initiation and growth mechanisms of defects in optical coatings, investigate failure mechanisms of laser coatings, and suggest methods for reducing the number of defects during the deposition process. To date, our defect analysis using non-optical techniques has focused on hafnia/silica multilayers for high power lasers. In summary, the information we have compiled about the defect seeds: indicates that seed size has an influence upon the mechanical stability of the whole defect, indicates that seed shape and chemical composition reveal potential seed sources in the coating system, and demonstrates that defects can be initiated either as a single event or continuously during the deposition process. Also, it is shown that different vendors have characteristic defects and seeds

  20. Optical investigations of high pressure glow discharges based on MSE arrays

    Energy Technology Data Exchange (ETDEWEB)

    Penache, C.; Hohn, O.; Schmidt-Boecking, H. [Frankfurt Univ. (Germany); Spielberger, L. [Deutsche Gesellschaft fuer Technische Zusammenarbeit GmbH (GTZ), Eschborn (Germany); Braeuning-Demian, A.; Penache, D. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)

    2001-07-01

    The micro-structure-electrode (MSE) arrays are providing a non-thermal high pressure plasma. These arrays consist of a matrix of holes perforated in a thin multilayer made out of two metallic foils separated by a dielectric. The holes diameter and the thickness of the insulator spacer need to be around 100 {mu}m to allow for the MSE operation at pressure ranging from 0.1 to 1 bar and above. In this work single direct current microdischarges and systems of parallel operated holes in argon at 0.2 bar have been optically investigated. The spatial distribution of the emitted light has been monitored by a digital camera connected to an optical microscope. The UV photon emission has been recorded by a position sensitive photon detector allowing for space and time resolved measurements. Its time resolution of about 1 nsec makes possible the investigation of fast processes, e.g. the constriction of the discharge. Due to its typical position resolution of 100 {mu}m, this detector needs to be used in combination with an optical system allowing for the magnification of the discharge area. The optical appearance show a stable, volume filling glow discharge, fact proved also by the typical current-voltage characteristic.

  1. Nonlinear optical switching behavior in the solid state: A theoretical investigation on anils

    KAUST Repository

    Ségerie, Audrey

    2011-09-13

    The linear (π(1)) and second-order nonlinear (π(2)) optical properties of two anil crystals, [N-(4-hydroxy)-salicylidene-amino-4-(methylbenzoate) and N-(3,5-di-tert- butylsalicylidene)-4-aminopyridine, denoted 4A and 4P, respectively], as well as the optical contrasts upon switching between their enol (E) and keto (K) forms, have been investigated by combining the molecular responses calculated using quantum chemistry methods and an electrostatic interaction scheme to account for the local field effects. It is found that intermolecular interactions impact differently the K/E optical contrasts in the two systems, which illustrates the importance of the supramolecular organization on the macroscopic responses. In 4A, the surrounding effects on the (hyper)polarizabilities are similar in the enol and keto forms, leading to optical contrasts very close to those of the isolated molecule. In contrast, an enhancement of the second-order susceptibility is observed in the keto form of 4P, leading to a large π(2)(K)/π(2)(E) contrast. Moreover, the π(2)(4A)/π(2)(4P) ratio for the most stable enol forms is obtained to be in good agreement with previous experimental investigations, which supports the reliability of the computational procedure. © 2011 American Chemical Society.

  2. Investigation of Optical and Luminescence Properties of Soda Lime Borate Glasses Doped with Sm3+ Ion

    Institute of Scientific and Technical Information of China (English)

    FALAK Zaman; GUL Rooh; NATTAPON Srisittipokakun; JACKRAPONG Kaewkhao

    2016-01-01

    This paper was to investigate the optical and luminescence properties of Sm3+ doped SLB glasses by a melt quenching technique. The optical and luminescence properties of the prepared glass samples were investigatedvia ab-sorption and photoluminescence spectra, respectively. The related physical and optical parameters were also calculated. From optical absorption measurements, the transition6H5/2→6P3/2at 403 nm has a higher spectral intensity and is a hypersensitive transition. From photoluminescence spectra, four prominent emission spectra appear. The most intense band is located at4G5/2→6H9/2(599 nm), which is the characteristic emission range of Sm3+ ions with the reddish orange color. The experimental decay time of the4G5/2 level of Sm3+ SLB glasses was determined. The decay time decreases from 1.367 to 0.333 ms with increasing the content of Sm3+. The color coordinates (x,y) of the prepared glasses passes through the reddish-orange region in the CIE 1931 diagram and are suitable for orange LEDs, optoelectronics, and solid- state lighting. The further investigation on the optimization of the dopant content in the SLB glasses was suggested.

  3. Investigation of light propagation methods used to calculate wave-optical PSF

    Science.gov (United States)

    Horiuchi, Shuma; Yoshida, Shuhei; Yamamoto, Manabu

    2015-09-01

    In this study, we investigated the suitability of various light propagation methods and their usefulness in terms of calculating the wave-optical point spread function (PSF) of an optical imaging system. To analyze an aberration in an optical imaging system in order to obtain its PSF, light propagation methods are widely used to obtain the light intensity distribution on the observation plane. Both the Fresnel-Kirchhoff and Rayleigh-Sommerfeld diffraction formulae are commonly used in light propagation simulations. Recently, there have been many reports concerning light propagation methods in the field of digital holography. These methods are based on the Rayleigh-Sommerfeld diffraction formula and use discrete Fourier transformation. These methods are referred to as the angular spectrum and Fresnel diffraction methods. In this study, these propagation methods are evaluated in terms of the degree of accuracy offered and their associated calculation costs. In order to demonstrate and investigate the features of these propagation methods, we employed a Tessar lens system, which is composed of four lenses. The wavefront aberration of the lens system is obtained by a ray tracing simulation and is used to generate the generalized pupil function. Next, the Rayleigh- Sommerfeld diffraction formula and the light propagation method based on this formula are used to calculate the waveoptical PSF using the pupil function. We applied these simulation methods to various recently proposed propagation methods and discussed the suitability of the various light propagation methods under consideration for calculating the wave-optical PSF.

  4. Moessbauer and optical investigation of Eu:YAG nanocrystals synthesized by a sol-gel method

    International Nuclear Information System (INIS)

    The morphological changes induced by the thermal treatments of YAG: Eu crystals synthesized by a sol-gel method have been investigated using the Moessbauer and optical techniques. Both methods exhibit a drastic change of the spectral parameters at amorphous - garnet phase transition, followed by a slow evolution of these parameters with the increase of the annealing temperature. This slow evolution is due to the increase in size of the nanocrystals. (authors)

  5. Sol–gel synthesized zinc oxide nanorods and their structural and optical investigation for optoelectronic application

    OpenAIRE

    Foo, Kai Loong; Hashim, Uda; Muhammad, Kashif; Voon, Chun Hong

    2014-01-01

    Nanostructured zinc oxide (ZnO) nanorods (NRs) with hexagonal wurtzite structures were synthesized using an easy and low-cost bottom-up hydrothermal growth technique. ZnO thin films were prepared with the use of four different solvents, namely, methanol, ethanol, isopropanol, and 2-methoxyethanol, and then used as seed layer templates for the subsequent growth of the ZnO NRs. The influences of the different solvents on the structural and optical properties were investigated through scanning e...

  6. Investigation And Application Of The Frustrated-Total-Internal-Reflection Phenomenon in Optical Fibers

    OpenAIRE

    Rahnavardy, K.; Arya, Vivek; Wang, A.; Weiss, J.M.

    1997-01-01

    A detailed investigation of the frustrated-total-internal-reflection (FTIR) phenomenon in silica-glass-based optical fibers and its application to simple intensity-modulated strain and pressure sensors is presented. Such sensors may be readily fabricated with silica-based fibers and can be easily modified with sapphire fibers for high-temperature industrial applications where conventional silica-based fiber sensors are not feasible. We present the all-fiber FTIR sensor and show good correlati...

  7. Investigation and validation of the openflow protocol for next generation converged optical networks

    OpenAIRE

    Vujosevic, Pavle

    2011-01-01

    English: Considering the extension to the circuit switching environment, the work describes abilities of converged packet and circuit networks such as: dynamic packet link establishing, application-aware traffic aggregation and service specific routing. In addition to this, the overlay architecture for interoperability of GMPLS and OpenFlow has been suggested and FlowVisor capabilities in virtualization of optical networks have been investigated. At the end, the architecture of a real OpenFlo...

  8. Electron accelerator with a laser ignition for investigation of beam plasma by optical methods

    International Nuclear Information System (INIS)

    Facility to conduct investigations into dense gas beam plasma is described. Facility comprises: electron accelerator (200-300 keV, 5kA, 20ns), OGM-40 ignition ruby laser LZhI-501 diagnostic laser (with 0.55-0.66 μm tunable wave length), Michelson interferometer and diagnostic equipment for optical measurements. Laser ignition of spark gap is introduced to strong synchronization (±10ns) of radiation pulse of diagnostic laser with beam current pulse

  9. Investigation of the corrosion behaviour of a bilayer cerium-silane pre-treatment on Al 2024-T3 in 0.1 M NaCl

    International Nuclear Information System (INIS)

    In the last few years great efforts have been made in order to find environmentally friendly substitutes for Cr6+ pre-treatments applied to aluminium alloys used in the aircraft industry. In this work we have investigated the electrochemical response of a bilayer pre-treatment consisting of a Ce conversion bottom layer and a non-functional silane (bis-1,2-(triethoxysilyl) ethane (BTSE)) top layer applied on Al 2024-T3, and compared its behaviour with monolayer coated samples. The investigation was carried out in 0.1 M NaCl solution, and the electrochemical techniques employed were anodic polarization curves and electrochemical impedance spectroscopy (EIS). EIS experiments performed with bilayer coated samples have shown a continuous increase of the impedance response during the whole test period, which was interpreted on the basis of a pore blocking mechanism supported by scanning electron microscopy (SEM) images and equivalent circuit fitting. Moreover, the impedance of the bilayer coated samples was approximately one order of magnitude higher than that presented by monolayer coated ones. On the other hand, mechanical tests have evidenced the good adhesion of the silane layer to the Ce conversion layer, which can be likely attributed to a better linking between the silane molecules and the cerium bottom layer

  10. Um exercício rigoroso de investigação clínica A rigorous exercise on clinical investigation

    Directory of Open Access Journals (Sweden)

    Angélica Bastos

    2007-12-01

    Full Text Available O artigo visa extrair da produção psicanalítica de Juan Carlos Cosentino as coordenadas de sua investigação. Com base no procedimento segundo o qual Freud concebeu a elaboração do saber em psicanálise, busca-se delimitar suas questões clínicas. Nas fobias, na angústia e nos sonhos, o psicanalista distingue duas ordens de laço na experiência analítica: por um lado, a fantasia e a neurose de transferência, e, por outro, a estrutura. Procura-se demonstrar o quanto sua releitura de Freud é movida por problemáticas originais, configurando uma pesquisa rigorosa impulsionada pela direção do tratamento e ditada pela função do desejo do analista.The article aims at drawing out the coordinates of investigation from the psychoanalytical production of Juan Carlos Cosentino. Based on the proceedings which Freud conceived knowledge elaboration in psychoanalysis, the clinical questions are delimited in his investigation. The psychoanalyst distinguishes two bond types in the analytical experience in relation to phobias, angst and dreams: on one hand, fantasy and transfer neurosis and on the other hand, the structure. We try to demonstrate how much his reading on Freud is powered by original problems, thus outlining a rigorous research triggered by the treatment course and ruled by the function of the therapist's desire.

  11. Thermoluminescence and F centers of manganese doped NaCl and NaCl-CKl crystals exposed to gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Somera, L.; Cruz Z, E.; Roman L, J. [UNAM, Instituto de Ciencias Nucleares, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Hernandez A, J. M.; Murrieta S, H., E-mail: ecruz@nucleares.unam.mx [UNAM, Instituto de Fisica, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2015-10-15

    Alkali halides crystals doped with rare earths or transition metals have been widely studied due to the luminescence properties. In particular, NaCl and KCl single crystals present thermally stimulated luminescence (Tl) after gamma irradiation. The NaCl and the NaCl KCl mixed crystal doped with manganese (MnCl{sub 2}) impurity were grown by using the Czochralski method. The emission characteristic of Mn{sup 2+} was observed at 543 nm. The crystals were exposed between 0.02 and 10 kGy gamma dose from {sup 60}Co irradiator. Optical absorption at room temperature shows the peaked band at 452 nm corresponding to the manganese impurity. The F bands, was ascribed to the electron trapped in the anion vacancy in the lattice, were obtained at 452 nm and 455 nm belonging to NaCl:Mn and NaCl KCl:Mn, respectively. The F band increases as the doses increase and it was bleaching by the UV light at 470 nm. The glow curves of the samples show the first glow peak between 92-103 degrees C, while the second main peak was observed at 183 degrees C for the undoped NaCl and at 148 and 165 degrees C for the NaCl:Mn and NaCl-KCl:Mn, respectively. The main peak was slowly bleaching when the irradiated sample was illuminated with F (470 nm) light. Optical bleaching confirms that the F center has an important participation in the thermoluminescent response. The glow curves structure from the thermal bleaching suggests the participation of different kind of traps. Also, the kinetics parameters such as activation energy (E), frequency factor (s) and the kinetic order (b) were investigated. (Author)

  12. Thermoluminescence and F centers of manganese doped NaCl and NaCl-CKl crystals exposed to gamma radiation

    International Nuclear Information System (INIS)

    Alkali halides crystals doped with rare earths or transition metals have been widely studied due to the luminescence properties. In particular, NaCl and KCl single crystals present thermally stimulated luminescence (Tl) after gamma irradiation. The NaCl and the NaCl KCl mixed crystal doped with manganese (MnCl2) impurity were grown by using the Czochralski method. The emission characteristic of Mn2+ was observed at 543 nm. The crystals were exposed between 0.02 and 10 kGy gamma dose from 60Co irradiator. Optical absorption at room temperature shows the peaked band at 452 nm corresponding to the manganese impurity. The F bands, was ascribed to the electron trapped in the anion vacancy in the lattice, were obtained at 452 nm and 455 nm belonging to NaCl:Mn and NaCl KCl:Mn, respectively. The F band increases as the doses increase and it was bleaching by the UV light at 470 nm. The glow curves of the samples show the first glow peak between 92-103 degrees C, while the second main peak was observed at 183 degrees C for the undoped NaCl and at 148 and 165 degrees C for the NaCl:Mn and NaCl-KCl:Mn, respectively. The main peak was slowly bleaching when the irradiated sample was illuminated with F (470 nm) light. Optical bleaching confirms that the F center has an important participation in the thermoluminescent response. The glow curves structure from the thermal bleaching suggests the participation of different kind of traps. Also, the kinetics parameters such as activation energy (E), frequency factor (s) and the kinetic order (b) were investigated. (Author)

  13. Four new chalcohalides, NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl: Syntheses, crystal structures and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chao; Feng, Kai; Tu, Heng [Center for Crystal Research and Development, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Yao, Jiyong, E-mail: jyao@mail.ipc.ac.cn [Center for Crystal Research and Development, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Wu, Yicheng [Center for Crystal Research and Development, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2015-07-15

    Four new chalcohalides, namely NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br, and CsBa{sub 2}SnS{sub 4}Cl, have been synthesized by the conventional high temperature solid-state reactions. They crystallize in three different space groups: space group I4/mcm for NaBa{sub 2}SnS{sub 4}Cl and KBa{sub 2}SnS{sub 4}Cl, Pnma for KBa{sub 2}SnS{sub 4}Br, and P2{sub 1}/c for CsBa{sub 2}SnS{sub 4}Cl. In all four compounds, the X{sup −} halide anions are only connected to six alkali metal or Ba cations, and the Sn atoms are only tetrahedrally enjoined to four S atoms. However, the M–X–Ba pseudo layers and the SnS{sub 4} tetrahedra are arranged in different ways in the three structural types, which demonstrates the interesting effect of ionic radii on the crystal structures. UV–vis–NIR spectroscopy measurements indicate that NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br, and CsBa{sub 2}SnS{sub 4}Cl have band gaps of 2.28, 2.30, 1.95, and 2.06 eV, respectively. - Graphical abstract: A new series of chalcohalides, NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl have been obtained. They present three different space groups: NaBa{sub 2}SnS{sub 4}Cl and KBa{sub 2}SnS{sub 4}Cl in space group I4/mcm, KBa{sub 2}SnS{sub 4}Br in Pnma and CsBa{sub 2}SnS{sub 4}Cl in space group P2{sub 1}/c. UV–vis–NIR spectroscopy measurements indicate that NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl have band gaps of 2.28, 2.30 1.95, and 2.06 eV, respectively. - Highlights: • Four new chalcohalides, NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl were obtained. • They adopt three different structures owing to different ionic radii and elemental electronegativity. • NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl have band gaps

  14. Fibres reinforced dentures investigated with en-face optical coherence tomography

    Science.gov (United States)

    Negrutiu, Meda L.; Sinescu, Cosmin; Hughes, Michael; Bradu, Adrian; Goguta, Luciana; Rominu, Mihai; Negru, Radu; Podoleanu, Adrian Gh.

    2008-04-01

    The complete dentures are currently made using different technologies. In order to avoid deficiencies of the prostheses made using the classical technique, several alternative procedures have been devised. In order to enhance the mechanical strength, complete denture bases are reinforced with fibres. Their material and structure vary wildly, which makes the investigation difficult. In this study, optical coherence tomography (OCT) is evaluated as a possible non-invasive technique to assess the biomechanical behaviour of the reinforcing fibres. OCT images demonstrate structural defects between fibres and the acrylic material in all dentures bases investigated. We conclude that OCT can successfully be used as a noninvasive analysis method.

  15. Optical waveguide lightmode spectroscopic techniques for investigating membrane-bound ion channel activities.

    Science.gov (United States)

    Székács, Inna; Kaszás, Nóra; Gróf, Pál; Erdélyi, Katalin; Szendrő, István; Mihalik, Balázs; Pataki, Agnes; Antoni, Ferenc A; Madarász, Emilia

    2013-01-01

    Optical waveguide lightmode spectroscopic (OWLS) techniques were probed for monitoring ion permeation through channels incorporated into artificial lipid environment. A novel sensor set-up was developed by depositing liposomes or cell-derived membrane fragments onto hydrophilic polytetrafluoroethylene (PTFE) membrane. The fibrous material of PTFE membrane could entrap lipoid vesicles and the water-filled pores provided environment for the hydrophilic domains of lipid-embedded proteins. The sensor surface was kept clean from the lipid holder PTFE membrane by a water- and ion-permeable polyethylene terephthalate (PET) mesh. The sensor set-up was tested with egg yolk lecithin liposomes containing gramicidin ion channels and with cell-derived membrane fragments enriched in GABA-gated anion channels. The method allowed monitoring the move of Na(+) and organic cations through gramicidin channels and detecting the Cl(-)-channel functions of the (α5β2γ2) GABAA receptor in the presence or absence of GABA and the competitive GABA-blocker bicuculline. PMID:24339925

  16. Optical waveguide lightmode spectroscopic techniques for investigating membrane-bound ion channel activities.

    Directory of Open Access Journals (Sweden)

    Inna Székács

    Full Text Available Optical waveguide lightmode spectroscopic (OWLS techniques were probed for monitoring ion permeation through channels incorporated into artificial lipid environment. A novel sensor set-up was developed by depositing liposomes or cell-derived membrane fragments onto hydrophilic polytetrafluoroethylene (PTFE membrane. The fibrous material of PTFE membrane could entrap lipoid vesicles and the water-filled pores provided environment for the hydrophilic domains of lipid-embedded proteins. The sensor surface was kept clean from the lipid holder PTFE membrane by a water- and ion-permeable polyethylene terephthalate (PET mesh. The sensor set-up was tested with egg yolk lecithin liposomes containing gramicidin ion channels and with cell-derived membrane fragments enriched in GABA-gated anion channels. The method allowed monitoring the move of Na(+ and organic cations through gramicidin channels and detecting the Cl(--channel functions of the (α5β2γ2 GABAA receptor in the presence or absence of GABA and the competitive GABA-blocker bicuculline.

  17. Magneto-optical investigations of rare earth doped sol-gel derived silicate xerogels

    International Nuclear Information System (INIS)

    Rare-earth doped xerogels (Eu3+, Sm3+, Ho3+, Pr3+) were prepared by using the sol-gel method and their magneto-optical and optical properties have been studied. The Magnetic Circular Dichroism (MCD) spectra are quite similar to those recorded in the RE-doped fluorozirconate glasses; the fine structures shown by the MCD spectra are better resolved compared to the optical absorption spectra. The MCD technique has been correlated with optical measurements in order to investigate the site symmetry in the particular case of Eu3+-doped xerogel and oxyfluoride glasses. In the xerogel, coordination symmetry around the Eu3+ ions is close to D3h and is lower in the oxyfluoride glass. - Highlights: → Rare-earth doped xerogels (Eu3+, Sm3+, Ho3+, Pr3+) were prepared by the sol-gel method. → MCD and luminescence methods were applied to probe the site symmetry in europium doped xerogel and oxyfluoride glasses. → Rare-earth site symmetry is close to D3h in xerogel and is lower in oxyfluoride glass.

  18. Magneto-optical investigations of rare earth doped sol-gel derived silicate xerogels

    Energy Technology Data Exchange (ETDEWEB)

    Secu, C.E.; Polosan, S. [National Institute of Materials Physics, Optical Processes in Nanostructured Materials Department, P.O. Box MG-7, Bucharest-Magurele, 077125 (Romania); Secu, M., E-mail: msecu@infim.ro [National Institute of Materials Physics, Optical Processes in Nanostructured Materials Department, P.O. Box MG-7, Bucharest-Magurele, 077125 (Romania)

    2011-08-15

    Rare-earth doped xerogels (Eu{sup 3+}, Sm{sup 3+}, Ho{sup 3+}, Pr{sup 3+}) were prepared by using the sol-gel method and their magneto-optical and optical properties have been studied. The Magnetic Circular Dichroism (MCD) spectra are quite similar to those recorded in the RE-doped fluorozirconate glasses; the fine structures shown by the MCD spectra are better resolved compared to the optical absorption spectra. The MCD technique has been correlated with optical measurements in order to investigate the site symmetry in the particular case of Eu{sup 3+}-doped xerogel and oxyfluoride glasses. In the xerogel, coordination symmetry around the Eu{sup 3+} ions is close to D{sub 3h} and is lower in the oxyfluoride glass. - Highlights: > Rare-earth doped xerogels (Eu{sup 3+}, Sm{sup 3+}, Ho{sup 3+}, Pr{sup 3+}) were prepared by the sol-gel method. > MCD and luminescence methods were applied to probe the site symmetry in europium doped xerogel and oxyfluoride glasses. > Rare-earth site symmetry is close to D{sub 3h} in xerogel and is lower in oxyfluoride glass.

  19. Investigation of a BeO-based optically stimulated luminescence dosemeter

    International Nuclear Information System (INIS)

    The optical sensitivity of BeO-based luminophors has been well-known for many years. The optical stimulation of BeO with blue light is most effective. Then the dosemeters emit luminescent light in the ultraviolet-range around 325 nm. Matched on these facts a simple optically stimulated luminescence (OSL) treatment has been developed. Intense blue light-emitting diodes are used for cw-stimulation. A Hamamatsu solar blind photomultiplier detects the OSL-light. Good separation of both spectral ranges by optical filters is very important. The dosemeter has a linear dose response between ∼20 μGy and >10 Gy. It was suggested, that a modification of stimulation conditions would allow measurements down to 1 μGy. Fading, photon energy dependence and reproducibility of OSL-signal correspond well with requirements to clinical and personal dosemeters. In addition, basic questions of the OSL-process in BeO have been investigated. A relevant point of interest was the dependency of the OSL-signal on stimulation power. (authors)

  20. Performance Investigation of All-Optical NRZ-to-Manchester Format Conversion with SOA-MZI Based XOR Logic Gate

    International Nuclear Information System (INIS)

    All-optical format conversion between non-return-to-zero (NRZ) and the Manchester code is implemented by using an optical exclusive-OR (XOR) logic gate based on a semiconductor optical amplifier Mach-Zehnder Interferometer (SOA-MZI). There is 10 Gbit/s all-optical NRZ-to-Manchester conversion implemented in our simulation system and BER performance of the format conversion is investigated. Transmission performances of the converted Manchester coded signal are discussed in terms of transmission length and received optical power. (fundamental areas of phenomenology(including applications))

  1. Investigation of the influence of InGaN underlying layers on the optical properties of InGaN quantum well structures

    International Nuclear Information System (INIS)

    The optical properties of InGaN/InGaN multiple quantum wells (MQWs) with InGaN underlying layers (UL) on sapphire substrates have been comprehensively investigated by highly spatially and spectrally resolved cathodoluminescence microscopy (CL) at He temperature and by temperature dependent photoluminescence spectroscopy (PL). The Indium content of the UL was systematically varied from 1% to 4% between the samples. SEM and AFM measurements were used to examine the sample morphology. The evaluation of the temperature dependent PL measurements shows a rising activation energy of nonradiative centers with increasing In content. CL investigations of the sample surface show elongated structures in the integral intensity images and peak wavelength images, which becomes more spot-like with rising In content. The peak energy of the MQW luminescence shows a blueshift with rising In content which may be caused by a possible reduction of the quantum confined Stark effect (QCSE). At the same time the FWHM of the MQW emission is reduced from 27 meV to about 18 meV when introducing ULs.

  2. Pressure induced variation of second harmonic efficiency of K3B6O10Cl

    Science.gov (United States)

    Wang, Hui; Kong, Lingyao; Zhao, Xiaoyan; Lv, Zhenlong; Li, Tongwei; Ju, Wei Wei; You, Jinghan; Bai, Ying

    2013-09-01

    K3B6O10Cl is a perovskite-like nonlinear optical (NLO) crystal, which exhibits large second harmonic generation (SHG) response. Based on density-functional theory, we investigate the influence of pressure on SHG tensor of K3B6O10Cl. At zero pressure, the non-centrosymmetric distortion of K3B6O10Cl from BO4 tetrahedron results in the similar SHG tensor to β-BaB2O4 (BBO). At 50 GPa, the ClK6 octahedron distortion of K3B6O10Cl becomes the main source of SHG and give similar SHG tensor to LiNbO3. Therefore, pressure induces K3B6O10Cl from a BBO-like NLO material to a LiNbO3-like NLO material.

  3. A new modification of Ba[B5O8(OH)] · H2O, the refined structure of Ba2[B5O9]Cl · 0.5H2O, and the role of the pentaborate structural units in the formation of the quadratic optical nonlinearity

    International Nuclear Information System (INIS)

    The structure of a new modification of the barium pentaborate β-Ba[B5O8(OH)] · H2O synthesized under hydrothermal conditions is investigated. This structure differs from the previously studied structure of the α-Ba[B5O8(OH)] · H2O compound by a shorter interlayer spacing and a higher degree of filling of the intersheet space with water molecules and barium atoms (the space group P 1 bar is retained). The structure of the Ba2[B5O9] Cl · 0.5H2O pentaborate from the family of orthorhombic hilgardites (space group Pnn2) is refined, and the property of this crystal to generate the second optical harmonic is revealed. It is found that the previously studied pentaborate Ba5[B20O33(OH)4]H2O exhibits a nonlinear optical activity. The relationship between the structure and properties of hydrous and anhydrous pentaborates is discussed.

  4. Investigating the impact of NaCl salinity on growth, β-carotene, and chlorophyll a in the content life of halophytes of algae Chlorella sp.

    Directory of Open Access Journals (Sweden)

    Mojtaba Fathi

    2013-05-01

    Full Text Available Algae are used for many purposes as: food industry, animal feeding, soil enrichment andbiodiesel production. Chlorella is widely cultivated from microalgae species as it is rich in nutrients andhas its implementation as a healthy food use. In this study, the impact of NaCl salinity on growth, betacarotene,and chlorophyll a of Chlorella sp. has been investigated. This study results in three salinities(10, 30, 50 g L-1, respectively have shown that 30 g L-1 concentration has the highest value of cellnumber in day 15th and there was no significant difference between salinities on day 15th (p>0.05. Βetacaroteneresult has shown 50 g L-1 salinity and the highest value of beta-carotene did not indicate anystatistically significant differences between treatments (p>0.05. Chlorophyll a result has shown highestvalue in all treatments (it was in 50 g L-1. However, there was no significant difference betweensalinities on day 5th (p>0.05.

  5. Synthesis, crystal structure and optical properties of two new layered cadmium iodates: Cd(IO3)X (X=Cl, OH)

    International Nuclear Information System (INIS)

    Systematic explorations of new compounds in the cadmium iodate system by hydrothermal reactions led to two layered iodates, namely, Cd(IO3)X (X=Cl, OH). Cd(IO3)Cl crystallizes in the orthorhombic space group Cmca (No. 64) whereas Cd(IO3)(OH) crystallizes in the orthorhombic space group Pnma (No. 62). Cd(IO3)Cl displays a unique double layered structure composed of 1∞[Cd−O3Cl]n chains. Cadmium octahedrons form a 1D chain along the a-axis through edge sharing, and such chains are further interconnected via IO3 groups to form a special double layer on (020) plane. Cd(IO3)(OH) also exhibits a layered structure that is composed of cadmium cations, IO3 groups and hydroxyl ions. Within a layer, chains of CdO6 edge-shared octahedra are observed along the b-axis. And these chains are connected by IO3 groups into a layer parallel to the bc plane. Spectroscopic characterizations, elemental analysis, and thermogravimetric analysis for the reported two compounds are also presented. - Graphical abstract: Two new layered cadmium iodates Cd(IO3)X (X=Cl, OH) are reported. Cd(IO3)Cl features a unique double layered structure whereas Cd(IO3)(OH) displays an ordinary layered structure. - Highlights: • Two new layered cadmium iodates Cd(IO3)X (X=Cl, OH) are reported. • Cd(IO3)Cl features a unique double layered structure. • Cd(IO3)(OH) displays an ordinary layered structure. • The spectroscopic and thermal properties have been studied in detail

  6. Synthesis of MoSCl3 and investigating phase equilibria in the MCl3(M-Al,Fe) and MoCl5-MoSCl3 systems

    International Nuclear Information System (INIS)

    Molybdenum sulphochloride MoSCl3 has been synthesized. It is shown that in the MoCl5-MoSCl3 system the components interact by the eutectic scheme; eutectic corresponds to the content of 50 mol.% of MoSCl3 and to the melting point of 95 deg C. The AlCl3-MoSCl3 and FeCl3-MoSCl3 systems are of the eutectic type. The melting points and MoSCl3 content in the eutectic points are 9.5% and 180 deg C, and 10.7% and 290 deg C, respectively

  7. Investigations of electrical and optical properties of functional TCO thin films

    Directory of Open Access Journals (Sweden)

    Domaradzki Jarosław

    2015-06-01

    Full Text Available Transparent conducting oxide (TCO films of indium-tin-oxide were evaporated on the surface of silicon wafers after phosphorous diffusion and on the reference glass substrates. The influence of deposition process parameters (electron beam current, oxygen flow and the substrate temperature on optical and electrical properties of evaporated thin films were investigated by means of resistivity measurements and optical spectrophotometry. The performance of prepared thin films was judged by calculated figure of merit and the best result was obtained for the sample deposited on the substrate heated to the 100 °C and then removed from the deposition chamber and annealed in an air for 5 minutes at 400 °C. Refractive index and extinction coefficient were evaluated based on measured transmission spectra and used for designing of antireflection coating for solar cell. The obtained results showed that prepared TCO thin films are promising as a part of counter electrode in crystalline silicon solar cell construction.

  8. Optical modes in linear arrays of dielectric spherical particles: A numerical investigation

    CERN Document Server

    Blaustein, G S; Blaustein, Gail S.; Burin, Alexander L.

    2007-01-01

    We have investigated bound modes in finite linear chains of dielectric particles of various lengths, interparticle spacing and particle materials. Through a unique application of the multisphere Mie scattering formalism, we have developed numerical methods to calculate eigen-optical modes for various arrays of particles. These numerical methods involve the use of the multisphere scattering formalism as the entries in NxN matrices where N represents the number of particles in the chain. Eigenmodes of these matrices correspond to the eigen-optical modes of interest. We identified the eigenmodes with the highest quality factor by the application of a modified version of the Newton-Raphson algorithm. We found that convergence is strong using this algorithm for linear chains of up to several hundreds of particles. By comparing the dipolar approach with the more complex approach which utilizes a combination of both dipolar and quadrupolar approaches, we demonstrated that the dipolar approach has an accuracy of appr...

  9. High 36Cl/Cl ratios in Chernobyl groundwater

    International Nuclear Information System (INIS)

    After the explosion of the Chernobyl Nuclear Power Plant in April 1986, contaminated material was buried in shallow trenches within the exclusion zone. A 90Sr plume was evidenced downgradient of one of these trenches, trench T22. Due to its conservative properties, 36Cl is investigated here as a potential tracer to determine the maximal extent of the contamination plume from the trench in groundwater. 36Cl/Cl ratios measured in groundwater, trench soil water and leaf leachates are 1–5 orders of magnitude higher than the theoretical natural 36Cl/Cl ratio. This contamination occurred after the Chernobyl explosion and currently persists. Trench T22 acts as an obvious modern point source of 36Cl, however other sources have to be involved to explain such contamination. 36Cl contamination of groundwater can be explained by dilution of trench soil water by uncontaminated water (rainwater or deep groundwater). With a plume extending further than that of 90Sr, radionuclide which is impacted by retention and decay processes, 36Cl can be considered as a suitable tracer of contamination from the trench in groundwater provided that modern release processes of 36Cl from trench soil are better characterized. - Highlights: • High 36Cl/Cl ratios measured in the Chernobyl Pilot Site groundwater. • Trench T22 acts as a modern source of groundwater contamination by 36Cl but other sources are involved. • Contamination results from dilution of a contaminated “T22” soil water with rainwater. • Processes involved in the modern release need to be investigated

  10. Interaction of a pseudo-π C—C bond with cuprous and argentous chlorides: Cyclopropane⋯CuCl and cyclopropane⋯AgCl investigated by rotational spectroscopy and ab initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Zaleski, Daniel P.; Mullaney, John C.; Bittner, Dror M.; Walker, Nicholas R., E-mail: a.c.legon@bristol.ac.uk, E-mail: nick.walker@newcastle.ac.uk [School of Chemistry, Newcastle University, Bedson Building, Newcastle-Upon-Tyne NE1 7RU (United Kingdom); Tew, David P.; Legon, Anthony C., E-mail: a.c.legon@bristol.ac.uk, E-mail: nick.walker@newcastle.ac.uk [School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom)

    2015-10-28

    Strongly bound complexes (CH{sub 2}){sub 3}⋯MCl (M = Cu or Ag), formed by non-covalent interaction of cyclopropane and either cuprous chloride or argentous chloride, have been generated in the gas phase by means of the laser ablation of either copper or silver metal in the presence of supersonically expanded pulses of a gas mixture containing small amounts of cyclopropane and carbon tetrachloride in a large excess of argon. The rotational spectra of the complexes so formed were detected with a chirped-pulse, Fourier transform microwave spectrometer and analysed to give rotational constants and Cu and Cl nuclear quadrupole coupling constants for eight isotopologues of each of (CH{sub 2}){sub 3}⋯CuCl and (CH{sub 2}){sub 3}⋯AgCl. The geometry of each of these complexes was established unambiguously to have C{sub 2v} symmetry, with the three C atoms coplanar, and with the MCl molecule lying along a median of the cyclopropane C{sub 3} triangle. This median coincides with the principal inertia axis a in each of the two complexes (CH{sub 2}){sub 3}⋯MCl. The M atom interacts with the pseudo-π bond linking the pair of equivalent carbon atoms {sup F}C (F = front) nearest to it, so that M forms a non-covalent bond to one C—C edge of the cyclopropane molecule. The (CH{sub 2}){sub 3}⋯MCl complexes have similar angular geometries to those of the hydrogen- and halogen-bonded analogues (CH{sub 2}){sub 3}⋯HCl and (CH{sub 2}){sub 3}⋯ClF, respectively. Quantitative details of the geometries were determined by interpretation of the observed rotational constants and gave results in good agreement with those from ab initio calculations carried out at the CCSD(T)(F12*)/aug-cc-pVTZ-F12 level of theory. Interesting geometrical features are the lengthening of the {sup F}C—{sup F}C bond and the shrinkage of the two equivalent {sup B}C—{sup F}C (B = back) bonds relative to the C—C bond in cyclopropane itself. The expansions of the {sup F}C—{sup F}C bond are 0

  11. Microscopic investigations of the terahertz and the extreme nonlinear optical response of semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Golde, Daniel

    2010-06-22

    In the major part of this Thesis, we discuss the linear THz response of semiconductor nanostructures based on a microscopic theory. Here, two different problems are investigated: intersubband transitions in optically excited quantum wells and the THz plasma response of two-dimensional systems. In the latter case, we analyze the response of correlated electron and electron-hole plasmas. Extracting the plasma frequency from the linear response, we find significant deviations from the commonly accepted two-dimensional plasma frequency. Besides analyzing the pure plasma response, we also consider an intermediate regime where the response of the electron-hole plasma consists of a mixture of plasma contributions and excitonic transitions. A quantitative experiment-theory comparison provides novel insights into the behavior of the system at the transition from one regime to the other. The discussion of the intersubband transitions mainly focuses on the coherent superposition of the responses from true THz transitions and the ponderomotively accelerated carriers. We present a simple method to directly identify ponderomotive effects in the linear THz response. Apart from that, the excitonic contributions to intersubband transitions are investigated. The last part of the present Thesis deals with a completely different regime. Here, the extreme nonlinear optical response of low-dimensional semiconductor structures is discussed. Formally, extreme nonlinear optics describes the regime of light-matter interaction where the exciting field is strong enough such that the Rabi frequency is comparable to or larger than the characteristic transition frequency of the investigated system. Here, the Rabi frequency is given by the product of the electrical field strength and the dipole-matrix element of the respective transition. Theoretical investigations have predicted a large number of novel nonlinear effects arising for such strong excitations. Some of them have been observed in

  12. Aerosol optical thickness from Brewer spectrophotometers and an investigation into the stray-light effect.

    Science.gov (United States)

    Silva, Abel A; Kirchhoff, Volker W J H

    2004-04-20

    The Langley method has been applied to the measurements of direct solar radiation made by Brewer spectrophotometers to obtain the aerosol optical thickness (AOT) of the atmosphere in the ultraviolet-B range. In several cases the AOT increased with wavelength, which raises suspicion about the stray-light effect. To investigate the quality of the AOT measurements and the possibility of stray light, we conducted a campaign by using single- and double-monochromator Brewers. The campaign's results have shown that both Brewers' AOT values are in good agreement and that stray light is not an important effect for AOT at wavelengths above 306 nm. PMID:15119618

  13. Simulation Investigation on Optical and Electrical Properties of Carbon Nanotube in Terahertz Region

    International Nuclear Information System (INIS)

    Under the framework of Maxwell-Garnett (M-G) model, the optical and electrical properties of single-walled carbon naotube (SWCNT), double-walled carbon nanotube (DWCNT) and hydrogen-doped carbon nanotube (H-doped CNT) in terahertz (THz) region have been investigated. It has been found that as frequency increases the loss tangent and conductivity show a peak. The loss tangent and conductivity of SWCNT is larger than that of DWCNT and H-doped CNT. The loss tangent and conductivity increase with the increases of filling factor and the decreases of geometrical factor.

  14. Systematically investigating the polarization gradient cooling in an optical molasses of ultracold cesium atoms

    Science.gov (United States)

    Ji, Zhong-Hua; Yuan, Jin-Peng; Zhao, Yan-Ting; Chang, Xue-Fang; Xiao, Lian-Tuan; Jia, Suo-Tang

    2014-11-01

    We systematically investigate the polarization gradient cooling (PGC) process in an optical molasses of ultracold cesium atoms. The SR mode for changing the cooling laser, which means that the cooling laser frequency is stepped to the setting value while its intensity is ramped, is found to be the best for the PGC, compared with other modes studied. We verify that the heating effect of the cold atoms, which appears when the cooling laser intensity is lower than the saturation intensity, arises from insufficient polarization gradient cooling. Finally, an exponential decay function with a statistical explanation is introduced to explain the dependence of the cold atom temperature on the PGC interaction time.

  15. Investigating The Vortex Melting Phenomenon In BSCCO Crystals Using Magneto-Optical Imaging Technique

    OpenAIRE

    Soibel, A.; Banerjee, S. S.; Myasoedov, Y.; Rappaport, M.L.; E. Zeldov; Ooi, S.; Tamegai, T.

    2002-01-01

    Using a novel differential magneto-optical imaging technique we investigate the phenomenon of vortex lattice melting in crystals of Bi_2Sr_2CaCu_2O_8 (BSCCO). The images of melting reveal complex patterns in the formation and evolution of the vortex solid-liquid interface with varying field (H) or temperature (T). We believe that the complex melting patterns are due to a random distribution of material disorder or inhomogeneities across the sample, which create fluctuations in the local melti...

  16. Investigation of the optical response of photonic crystal nanocavities in ferroelectric oxide thin film

    International Nuclear Information System (INIS)

    The optical properties of BaTiO3 two dimensional photonic crystal (PhC) nanocavities were investigated. Two types of nanocavities consisting of dopants and vacancies with PhC periodicities ranging from 200 to 550 nm were evaluated. The images from laser scanning confocal microscopy show the optical scattering of the PhC cavities is highly wavelength dependent. An optical intensity reversal is observed when the wavelength of probe light shifts by 29 nm. Meanwhile, intensity contrast between the nanocavity and its adjacent PhCs is enhanced as the PhC periodicity becomes shorter than the probe wavelength. To determine the photonic band structures fluorescence from dye covered PhCs were imaged and analyzed. A strong enhancement of fluorescence is observed for the PhC with a period of 200 nm. Upon comparison to the 2D finite difference time domain calculations, the enhancement is attributed to strong light localization within the PhC nanocavity. As a result, the in-plane lightwave propagation is prohibited that results in an increase in the vertical light scattering. (paper)

  17. Preparation and investigation of Ge-S-I glasses for infrared fiber optics

    Science.gov (United States)

    Velmuzhov, A. P.; Sukhanov, M. V.; Plekhovich, A. D.; Snopatin, G. E.; Churbanov, M. F.; Iskhakova, L. D.; Ermakov, R. P.; Kotereva, T. V.; Shiryaev, V. S.

    2016-02-01

    Glass samples of [GeSx]90I10 (x = 1.5, 1.7, 2.0, 2.3, 2.45, 2.6) compositions were prepared, and some their thermal, optical properties as well as tendency to crystallization were investigated. The compositional dependences of glass transition temperature, volume fraction of crystallized phase and activation energy of glass formation (Eg) have nonmonotonic character with a maximum for [GeS2.0]90I10 glass. Glasses of 85.8GeS2-14.2GeI4 and [GeS1.5]90I10 compositions are identified as promising for preparation of optical fiber. For the first time, Ge-S-I glass fibers were produced. Minimum optical losses in 85.8GeS2-14.2GeI4 glass fiber were 2.7 dB/m at a wavelength of 5.1 μm, and that in [GeS1.5]90I10 glass fiber were 14.5 dB/m at 5.5 μm.

  18. Investigation of radiative effects of the optically thick dust layer over the Indian tropical region

    Energy Technology Data Exchange (ETDEWEB)

    Das, S.K.; Chen, J.P. [National Taiwan Univ. (China). Dept. of Atmospheric Sciences; Ratnam, M. Venkat; Jayaraman, A. [National Atmospheric Research Laboratory, Tirupati (India)

    2013-06-01

    Optical and physical properties of aerosols derived from multi-satellite observations (MODIS-Aqua, OMI-Aura, MISR-Terra, CALIOP-CALIPSO) have been used to estimate radiative effects of the dust layer over southern India. The vertical distribution of aerosol radiative forcing and heating rates are calculated with 100m resolution in the lower atmosphere, using temperature and relative humidity data from balloon-borne radiosonde observations. The present study investigates the optically thick dust layer of optical thickness 0.18 {+-} 0.06 at an altitude of 2.5 {+-} 0.7 km over Gadanki, transported from the Thar Desert, producing radiative forcing and heating rate of 11.5 {+-} 3.3 W m{sup -2} and 0.6 {+-} 0.26 K day{sup -1}, respectively, with a forcing efficiency of 43 W m{sup -2} and an effective heating rate of 4Kday-1 per unit dust optical depth. Presence of the dust layer increases radiative forcing by 60% and heating rate by 60 times at that altitude compared to nondusty cloud-free days. Calculation shows that the radiative effects of the dust layer strongly depend on the boundary layer aerosol type and mass loading. An increase of 25% of heating by the dust layer is found over relatively cleaner regions than urban regions in southern India and further 15% of heating increases over the marine region. Such heating differences in free troposphere may have significant consequences in the atmospheric circulation and hydrological cycle over the tropical Indian region. (orig.)

  19. Investigation of radiative effects of the optically thick dust layer over the Indian tropical region

    Directory of Open Access Journals (Sweden)

    S. K. Das

    2013-04-01

    Full Text Available Optical and physical properties of aerosols derived from multi-satellite observations (MODIS-Aqua, OMI-Aura, MISR-Terra, CALIOP-CALIPSO have been used to estimate radiative effects of the dust layer over southern India. The vertical distribution of aerosol radiative forcing and heating rates are calculated with 100 m resolution in the lower atmosphere, using temperature and relative humidity data from balloon-borne radiosonde observations. The present study investigates the optically thick dust layer of optical thickness 0.18 ± 0.06 at an altitude of 2.5 ± 0.7 km over Gadanki, transported from the Thar Desert, producing radiative forcing and heating rate of 11.5 ± 3.3 W m−2 and 0.6 ± 0.26 K day−1, respectively, with a forcing efficiency of 43 W m−2 and an effective heating rate of 4 K day−1 per unit dust optical depth. Presence of the dust layer increases radiative forcing by 60% and heating rate by 60 times at that altitude compared to non-dusty cloud-free days. Calculation shows that the radiative effects of the dust layer strongly depend on the boundary layer aerosol type and mass loading. An increase of 25% of heating by the dust layer is found over relatively cleaner regions than urban regions in southern India and further 15% of heating increases over the marine region. Such heating differences in free troposphere may have significant consequences in the atmospheric circulation and hydrological cycle over the tropical Indian region.

  20. High (36)Cl/Cl ratios in Chernobyl groundwater.

    Science.gov (United States)

    Roux, Céline; Le Gal La Salle, Corinne; Simonucci, Caroline; Van Meir, Nathalie; Fifield, L Keith; Diez, Olivier; Bassot, Sylvain; Simler, Roland; Bugai, Dmitri; Kashparov, Valery; Lancelot, Joël

    2014-12-01

    After the explosion of the Chernobyl Nuclear Power Plant in April 1986, contaminated material was buried in shallow trenches within the exclusion zone. A (90)Sr plume was evidenced downgradient of one of these trenches, trench T22. Due to its conservative properties, (36)Cl is investigated here as a potential tracer to determine the maximal extent of the contamination plume from the trench in groundwater. (36)Cl/Cl ratios measured in groundwater, trench soil water and leaf leachates are 1-5 orders of magnitude higher than the theoretical natural (36)Cl/Cl ratio. This contamination occurred after the Chernobyl explosion and currently persists. Trench T22 acts as an obvious modern point source of (36)Cl, however other sources have to be involved to explain such contamination. (36)Cl contamination of groundwater can be explained by dilution of trench soil water by uncontaminated water (rainwater or deep groundwater). With a plume extending further than that of (90)Sr, radionuclide which is impacted by retention and decay processes, (36)Cl can be considered as a suitable tracer of contamination from the trench in groundwater provided that modern release processes of (36)Cl from trench soil are better characterized. PMID:25128774

  1. In situ UV-vis investigation of growth of gold nanoparticles prepared by solution plasma sputtering in NaCl solution

    Science.gov (United States)

    Mizutani, Tsuyoshi; Ogawa, Satoshi; Murai, Takaaki; Nameki, Hirofumi; Yoshida, Tomoko; Yagi, Shinya

    2015-11-01

    Gold nanoparticles are prepared in various concentrations of NaCl solutions by solution plasma sputtering. The absorption spectra of these solutions during and after the plasma process are measured by in situ ultraviolet-visible (UV-vis) spectroscopy to estimate the particle diameters and concentrations of gold. The distributions of particle diameters are obtained by transmission electron microscope (TEM) observations. These experiments indicate the gold nanoparticles with about 2.2 nm are directly formed by plasma phase and the diameters are increasing over time. These increases of particle diameters are caused by Ostwald ripening of gold nanoparticles in NaCl solution. We estimate the equilibrium diameter at which the gold nanoparticles are not solved in NaCl solution using in situ UV-vis spectroscopy. These diameters are about 5, 7 and 10 nm in 3, 5 and 10 mM NaCl solution, respectively. We make it possible to control the diameter of gold nanoparticles prepared by solution plasma sputtering in NaCl solution.

  2. Combined Electrical, Optical and Nuclear Investigations of Impurities and Defects in II-VI Semiconductors

    CERN Multimedia

    2002-01-01

    % IS325 \\\\ \\\\ To achieve well controlled bipolar conductivity in II-VI semiconductors represents a fundamental problem in semiconductor physics. The doping problems are controversely discussed, either in terms of self compensation or of compensation and passivation by unintentionally introduced impurities. \\\\ \\\\It is the goal of our experiments at the new ISOLDE facility, to shed new light on these problems and to look for ways to circumvent it. For this aim the investigation of impurities and native defects and the interaction between each other shall be investigated. The use of radioactive ion beams opens the access to controlled site selective doping of only one sublattice via nuclear transmutation. The compensating and passivating mechanisms will be studied by combining nuclear, electrical and optical methods like Perturbed Angular Correlation~(PAC), Hall Effect~(HE), Deep Level Transient Spectroscopy~(DLTS), Photoluminescence Spectroscopy~(PL) and electron paramagnetic resonance (EPR). \\\\ \\\\We intend to ...

  3. Investigating the influence of chromatic aberration and optical illumination bandwidth on fundus imaging in rats

    Science.gov (United States)

    Li, Hao; Liu, Wenzhong; Zhang, Hao F.

    2015-10-01

    Rodent models are indispensable in studying various retinal diseases. Noninvasive, high-resolution retinal imaging of rodent models is highly desired for longitudinally investigating the pathogenesis and therapeutic strategies. However, due to severe aberrations, the retinal image quality in rodents can be much worse than that in humans. We numerically and experimentally investigated the influence of chromatic aberration and optical illumination bandwidth on retinal imaging. We confirmed that the rat retinal image quality decreased with increasing illumination bandwidth. We achieved the retinal image resolution of 10 μm using a 19 nm illumination bandwidth centered at 580 nm in a home-built fundus camera. Furthermore, we observed higher chromatic aberration in albino rat eyes than in pigmented rat eyes. This study provides a design guide for high-resolution fundus camera for rodents. Our method is also beneficial to dispersion compensation in multiwavelength retinal imaging applications.

  4. Investigating the photosensitizer-potential of targeted gallium corrole using multimode optical imaging

    Science.gov (United States)

    Hwang, Jae Youn; Lubow, Jay; Chu, David; Gross, Zeev; Gray, Harry B.; Farkas, Daniel L.; Medina-Kauwe, Lali K.

    2011-02-01

    We recently developed a novel therapeutic particle, HerGa, for breast cancer treatment and detection. HerGa consists of a tumor-targeted cell penetration protein noncovalently assembled with a gallium-metallated corrole. The corrole is structurally similar to porphyrin, emits intense fluorescence, and has proven highly effective for breast tumor treatment preclinically, without light exposure. Here, we tested HerGa as a photosensitizer for photodynamic therapy and investigated its mechanism of action using multimode optical imaging. Using confocal fluorescence imaging, we observed that HerGa disrupts the mitochondrial membrane potential in situ, and this disruption is substantially augmented by light exposure. In addition, spectral and fluorescence lifetime imaging were utilized to both validate the mitochondrial membrane potential disruption and investigate HerGa internalization, allowing us to optimize the timing for light dosimetry. We observed, using advanced multimode optical imaging, that light at a specific wavelength promotes HerGa cytotoxicity, which is likely to cause disruption of mitochondrial function. Thus, we can identify for the first time the capacity of HerGa as a photosensitizer for photodynamic therapy and reveal its mechanism of action, opening possibilities for therapeutic intervention in human breast cancer management.

  5. Investigation of energy band gap and optical properties of cubic CdS epilayers

    International Nuclear Information System (INIS)

    High quality cubic CdS epilayers were grown on GaAs (1 0 0) substrates by the hot-wall epitaxy method. The crystal structure of the grown epilayers was confirmed to be the cubic structure by X-ray diffraction patterns. The optical properties of the epilayers were investigated in a wide photon energy range between 2.0 and 8.5 eV using spectroscopic ellipsometry (SE) and were studied in the transmittance spectra at a wavelength range of 400-700 nm at room temperature. The data obtained by SE were analyzed to find the critical points of the pseudodielectric function spectra, = 1(E)> + i2(E)>, such as E0, E1, E2, E'0, and E'1 structures. In addition, the optical properties related to the pseudodielectric function of CdS, such as the absorption coefficient α(E), were investigated. All the critical point structures were observed, for the first time, at 300 K by ellipsometric measurements for the cubic CdS epilayers. Also, the energy band gap was determined by the transmittance spectra of the free-standing film, and the results were compared with the E0 structure obtained by SE measurement

  6. Ge Nanoislands Grown by Radio Frequency Magnetron Sputtering: Comprehensive Investigation of Surface Morphology and Optical Properties

    Directory of Open Access Journals (Sweden)

    Alireza Samavati

    2015-01-01

    Full Text Available The comprehensive investigation of the effect of growth parameters on structural and optical properties of Si-based single layer Ge nanoislands grown via Stranski-Krastanov mechanism employing radio frequency magnetron sputtering due to its high deposition rate, easy procedure, economical cost, and safety is carried out. The estimated width and height of Ge nanoislands produced by this technique are in the range of ∼8 to ∼30 and ∼2 to 8 nm, respectively. Varieties parameters are manipulated to optimize the surface morphology and structural and optical behavior of Ge nanoislands. The resulted nanoislands are analyzed using various analytical techniques including atomic force microscope, X-ray diffraction, energy dispersive X-ray spectroscopy, room temperature photoluminescence, and Raman spectroscopy. The optimum parameters for growing high quality samples having high number density and homogenous and small size distribution are found to be 400°C for substrate temperature, 300 sec for deposition time, 10 sccm for Ar flow, and 100 W for radio frequency power. The excellent features of the results suggest that our systematic investigation on the organized growth factors and their effects on surface parameters and photoluminescence emission energy may constitute a basis for the tunable growth of Ge nanoislands (100 nanoislands suitable in nanophotonics.

  7. Synthesis, crystal structure and optical property of a novel metal chalcohalide: ZnHg{sub 3}Se{sub 2}Cl{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guodong; Xiong, Wei-Wei; Nie, Lina [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Zhang, Qichun, E-mail: qczhang@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)

    2015-10-15

    A novel chalcohalide ZnHg{sub 3}Se{sub 2}Cl{sub 4} has been synthesized through a solid state method and structurally characterized by single-crystal X-ray diffraction. It crystallizes in the acentric space group Cmc2{sub 1} (No. 36) with cell parameters a=7.3262(8) Å, b=12.518(2) Å, c=11.3324(14) Å. The compound consists of 12-membered Hg{sub 6}Se{sub 6} rings edge-sharing with six neighbored rings to construct a 2D layered network and the ZnCl{sub 4} tetrahedra are sandwiched between layers. TG-DTA measurement shows that the compound is thermally stable up to 300 °C. The band gap of the crystal is about 2.23 eV, and the crystal exhibits a broad transparent range from 0.56 to 13.8 µm. - Highlights: • A novel chalcohalide ZnHg{sub 3}Se{sub 2}Cl{sub 4} was synthesized by a solid state method. • The structure contains 12-membered Hg{sub 6}Se{sub 6} rings and ZnCl{sub 4} tetrahedra. • The band gap of the as-prepared compound is about 2.23 eV.

  8. Investigation of performance issues affecting optical circuit and packet switched WDM networks

    OpenAIRE

    Smyth, Frank

    2009-01-01

    Optical switching represents the next step in the evolution of optical networks. This thesis describes work that was carried out to examine performance issues which can occur in two distinct varieties of optical switching networks. Slow optical switching in which lightpaths are requested, provisioned and torn down when no longer required is known as optical circuit switching (OCS). Services enabled by OCS include wavelength routing, dynamic bandwidth allocation and protection switching...

  9. Investigation of optical properties of polymers exposed to radiation by high-energy krypton ions

    International Nuclear Information System (INIS)

    Full text: It's common knowledge that at high-energy ion modification a generation of defects induced by inelastic interaction is observed with formation of nuclear tracks in the bulk of irradiated material. When studying the structure of latent tracks in depth, 'a pile' set of thick polymer films is generally used. Nevertheless, it is rather difficult to maintain the same conditions of track etching for every film. What is more, it is preferable to get some information of continuous spectrum energy variation. For this purpose, absorbing filter as a metal foil of necessary thickness bent in a predetermined law is used in present work. On the surface of polymer films exposed to radiation an extended region is produced with the energy of bombardment particles varying within 0 till 250 MeV range. Owing to this region size which many times exceeds the projected distance, optical properties of ion-implanted polymer films have been studied. Based on performed investigations, it was shown that the character of flight transmission modification of spectrum blue region (420 nm) agrees well with the profile of bent in a parabolic law filter. In this case a decrease of heavy ion energy within 250 till 0 MeV range correlates with an increase of polymer film light transmission from 7 % to a value equal to studied parameter of non-irradiated sample - 35 %. So, optical density of films modified by high-energy krypton ions depends not only on ion fluence, but on their energy. When using absorbing profile filters, the obtained results allow to purposely distribute the implantation energy, and, consequently, to control light transmission of polymer films as promising and competitive materials for manufacture of functional elements of optics and electronics. Undoubtedly, this above- described method will also allow to considerably decrease energy expenses when using acceleration techniques owing to formation of ionic damage ability profiles of materials at single run

  10. Optical pumping of chemical HF lasers on the basis of NF3-H2 and ClF5-H2 mixtures by an open surface discharge in the bleaching-wave mode

    International Nuclear Information System (INIS)

    Lasing on HF upon optical pumping by emission of an open discharge, using NF3 and ClF5 as donors of fluorine atoms, was obtained for the first time in a chemical laser and the bleaching-wave mode was realised in a chemical HF laser. An open surface discharge was used as a pump source. The velocity of the bleaching wave, which was formed under its action, reached ∼8 km s-1. The formation of this wave leads to a rapid (with an ultrasonic velocity) replacement of the working medium in the lasing region, which provides a quantum laser efficiency close to unity. The optimum compo-sition of the working mixture was found to be NF3:H2:Kr =6:10:125 Torr. For this composition, the output laser energy in a 3.2-μs pulse reached ∼0.4 J and the specific output energy was 3.5 J litre-1. Approximately the same output characteristics of laser emission (0.35 J in a 3.5-μs pulse in the ClF5:H2:Kr=3:20:50 Torr mixture) were obtained in the system using ClF5 as donors of fluorine atoms. (lasers, active media)

  11. Non-Intrusive Magneto-Optic Detecting System for Investigations of Air Switching Arcs

    International Nuclear Information System (INIS)

    In current investigations of electric arc plasmas, experiments based on modern testing technology play an important role. To enrich the testing methods and contribute to the understanding and grasping of the inherent mechanism of air switching arcs, in this paper, a non-intrusive detecting system is described that combines the magneto-optic imaging (MOI) technique with the solution to inverse electromagnetic problems. The detecting system works in a sequence of main steps as follows: MOI of the variation of the arc flux density over a plane, magnetic field information extracted from the magneto-optic (MO) images, arc current density distribution and spatial pattern reconstruction by inverting the resulting field data. Correspondingly, in the system, an MOI set-up is designed based on the Faraday effect and the polarization properties of light, and an intelligent inversion algorithm is proposed that involves simulated annealing (SA). Experiments were carried out for high current (2 kA RMS) discharge cases in a typical low-voltage switchgear. The results show that the MO detection system possesses the advantages of visualization, high resolution and response, and electrical insulation, which provides a novel diagnostics tool for further studies of the arc. (low temperature plasma)

  12. Non-Intrusive Magneto-Optic Detecting System for Investigations of Air Switching Arcs

    Science.gov (United States)

    Zhang, Pengfei; Zhang, Guogang; Dong, Jinlong; Liu, Wanying; Geng, Yingsan

    2014-07-01

    In current investigations of electric arc plasmas, experiments based on modern testing technology play an important role. To enrich the testing methods and contribute to the understanding and grasping of the inherent mechanism of air switching arcs, in this paper, a non-intrusive detecting system is described that combines the magneto-optic imaging (MOI) technique with the solution to inverse electromagnetic problems. The detecting system works in a sequence of main steps as follows: MOI of the variation of the arc flux density over a plane, magnetic field information extracted from the magneto-optic (MO) images, arc current density distribution and spatial pattern reconstruction by inverting the resulting field data. Correspondingly, in the system, an MOI set-up is designed based on the Faraday effect and the polarization properties of light, and an intelligent inversion algorithm is proposed that involves simulated annealing (SA). Experiments were carried out for high current (2 kA RMS) discharge cases in a typical low-voltage switchgear. The results show that the MO detection system possesses the advantages of visualization, high resolution and response, and electrical insulation, which provides a novel diagnostics tool for further studies of the arc.

  13. Investigation of Optical and Electrical Properties of Silver Sulfide Films Deposited on Polyamide Substrates

    Directory of Open Access Journals (Sweden)

    Valentina KRYLOVA

    2013-03-01

    Full Text Available A low cost chemical bath deposition (CBD technique has been used for the preparation of Ag2S thin films on polyamide 6 (PA substrates. Optical and electrical properties of these films were investigated. Optical micrographs have shown that the surface morphology depends on the number of immersions, becoming more continuous and homogeneous. The UV/Vis absorption spectra show that peak observed at 240 nm is assigned to sulfide functional group and less intense shallower band observed at 350 nm is attributed to silver. Analysis of IR spectrum shows that a new material (silver sulfide is formed or bonded on the surface of PA after modification in acidic aqueous AgNO3/Na2S2O3·5H2O solution. The value of sheet resistance of silver sulfide layers varies from 39 MW/cm2 to 1.26 MW/cm2. The sheet resistance depends on the concentration of silver nitrate solution and number of samples immersions in precursor solutions.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3817

  14. Investigation on optical absorption properties of electrochemically formed porous InP using photoelectric conversion devices

    International Nuclear Information System (INIS)

    We investigated the optical absorption properties of InP porous structures formed by the electrochemical process using photoelectric conversion (PC) devices formed on p–n junction substrates. The photocurrent measurements revealed that the current from PC devices changed in response to the incident light power and the thickness of the top layer on the p–n interface. Since the photocarriers contributing to the observed photocurrents are excited by the photons reaching the p–n interface through the top layer, the photocurrents give us information on the optical absorption properties of the top layer. The photocurrents observed on a porous device with a porous structure in the top layer were lower than that of a non-porous device, indicating that the absorption properties of InP were enhanced after the formation of porous structures. This phenomenon can be explained in terms of absorption coefficient, α, increased by the light scattering and the sub-bandgap absorption in the porous layer.

  15. Nonlinear optical properties for a class of hexa-peri-hexabenzocoronene chromophores: a computational investigation.

    Science.gov (United States)

    Liu, Xiao-Ting; Guo, Jing-Fu; Ren, Ai-Min; Huang, Shuang; Feng, Ji-Kang

    2012-10-28

    The systematic investigation of the linear and nonlinear optical properties on such a class of hexa-peri-hexabenzocoronene (HBC) chromophores is of significance for rationally designing two-photon absorption (TPA) materials. The results indicate that increasing the strength of electron-donating or accepting terminal groups leads to bathochromic-shift of the absorption band and enhancement of the TPA cross section (δ(max)). For the molecules with fluorinated methylene and cyano substituents, replacement of a double bond by a triple bond in the conjugated linker produces the increase of δ(max), owing to the lower bond-length alternation and better rigidity of phenylene-ethynylene. In contrast, for the molecules with nitro groups, the similar replacement results in a slight decrease of δ(max) because N-HBC-E-NO2 has excellent planarity architecture and effective electronic coupling. The TPA spectra are red-shifted and the δ(max) values are enhanced as the number of branches increases. Thus, a solvatochromism effect has a positive influence on the TPA response of the nitryl compounds due to larger polarization of the nitro moiety. We have shed light on the linear relationship between the first hyperpolarizability and δ(max). These HBC derivatives hold potential as high-performance nonlinear optical materials. PMID:22940778

  16. Nano-spatial parameters from 3D to 2D lattice dimensionality by organic variant in [ZnCl4]- [R]+ hybrid materials: Structure, architecture-lattice dimensionality, microscopy, optical Eg and PL correlations

    Science.gov (United States)

    Kumar, Ajit; Verma, Sanjay K.; Alvi, P. A.; Jasrotia, Dinesh

    2016-04-01

    The nanospatial morphological features of [ZnCl]- [C5H4NCH3]+ hybrid derivative depicts 28 nm granular size and 3D spreader shape packing pattern as analyzed by FESEM and single crystal XRD structural studies. The organic moiety connect the inorganic components through N-H+…Cl- hydrogen bond to form a hybrid composite, the replacement of organic derivatives from 2-methylpyridine to 2-Amino-5-choloropyridine results the increase in granular size from 28nm to 60nm and unit cell packing pattern from 3D-2D lattice dimensionality along ac plane. The change in optical energy direct band gap value from 3.01eV for [ZnCl]- [C5H4NCH3]+ (HM1) to 3.42eV for [ZnCl]- [C5H5ClN2]+ (HM2) indicates the role of organic moiety in optical properties of hybrid materials. The photoluminescence emission spectra is observed in the wavelength range of 370 to 600 nm with maximum peak intensity of 9.66a.u. at 438 nm for (HM1) and 370 to 600 nm with max peak intensity of 9.91 a.u. at 442 nm for (HM2), indicating that the emission spectra lies in visible range. PL excitation spectra depicts the maximum excitation intensity [9.8] at 245.5 nm for (HM1) and its value of 9.9 a.u. at 294 nm, specify the excitation spectra lies in UV range. Photoluminescence excitation spectra is observed in the wavelength range of 280 to 350 nm with maximum peak intensity of 9.4 a.u. at 285.5 nm and 9.9 a.u. at 294 and 297 nm, indicating excitation in the UV spectrum. Single crystal growth process and detailed physiochemical characterization such as XRD, FESEM image analysis photoluminescence property reveals the structure stability with non-covalent interactions, lattice dimensionality (3D-2D) correlations interweaving into the design of inorganic-organic hybrid materials.

  17. INTERACTION OF LASER RADIATION WITH MATTER: Influence of Ca and Pb impurities on the bulk optical strength of ultrapure NaCl and KCl crystals

    Science.gov (United States)

    Vinogradov, An V.; Voszka, R.; Kovalev, Valerii I.; Faĭzullov, F. S.; Janszky, J.

    1987-06-01

    A significant increase (by a factor of about 3) of the bulk damage threshold in the case of interaction of CO2 laser radiation pulses with ultrapure NaCl and KCl crystals grown in a reactive atmosphere was observed on introduction of divalent metal ions Ca and Pb in concentrations of 10-5-10-6 mol/mol. Impurities were introduced in concentrations of 10-8-10-3 and 2×10-7-10-4 mol/mol into the melts of KCl and NaCl, respectively. The concentration of other impurities (including OH) did not exceed ~10-6 mol/mol. A physical model was developed to account for the observed dependence on the basis of an analogy between a system of colloidal particles and F centers in a crystal and a liquid-vapor system.

  18. Investigating photoexcitation-induced mitochondrial damage by chemotherapeutic corroles using multimode optical imaging

    Science.gov (United States)

    Hwang, Jae Youn; Lubow, David J.; Sims, Jessica D.; Gray, Harry B.; Mahammed, Atif; Gross, Zeev; Medina-Kauwe, Lali K.; Farkas, Daniel L.

    2012-01-01

    We recently reported that a targeted, brightly fluorescent gallium corrole (HerGa) is highly effective for breast tumor detection and treatment. Unlike structurally similar porphryins, HerGa exhibits tumor-targeted toxicity without the need for photoexcitation. We have now examined whether photoexcitation further modulates HerGa toxicity, using multimode optical imaging of live cells, including two-photon excited fluorescence, differential interference contrast (DIC), spectral, and lifetime imaging. Using two-photon excited fluorescence imaging, we observed that light at specific wavelengths augments the HerGa-mediated mitochondrial membrane potential disruption of breast cancer cells in situ. In addition, DIC, spectral, and fluorescence lifetime imaging enabled us to both validate cell damage by HerGa photoexcitation and investigate HerGa internalization, thus allowing optimization of light dose and timing. Our demonstration of HerGa phototoxicity opens the way for development of new methods of cancer intervention using tumor-targeted corroles.

  19. Optical and morphological investigation in interaction of dual dopants in poly(N-vinylcarzole)

    International Nuclear Information System (INIS)

    In this paper, we investigated the effect of the optical and electrical properties in poly(N-vinylcarzole) (PVK) doped with two dyes 8-tris-hydroxyquinoline (Alq3) and 4-(dicyanom-ethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran (DCJTB) on the energy transfer and charge trapping processes. The phase separation in blend films at different doping concentration was also studied. The results indicate that there is certain interaction between Alq3 and DCJTB. It is the incorporation of DCJTB that untangled the aggregation of Alq3 owing to the interaction of de-mixing of DCJTB in Alq3 domains. But for higher doping concentration of DCJTB, new aggregation domain result in an isolate charge transport channel that decreases the electroluminescence (EL) operating voltage

  20. System of laser pump and synchrotron radiation probe microdiffraction to investigate optical recording process

    International Nuclear Information System (INIS)

    We have developed a system of laser-pump and synchrotron radiation probe microdiffraction to investigate the phase-change process on a nanosecond time scale of Ge2Sb2Te5 film embedded in multi-layer structures, which corresponds to real optical recording media. The measurements were achieved by combining (i) the pump-laser system with a pulse width of 300 ps, (ii) a highly brilliant focused microbeam with wide peak-energy width (ΔE/E ∼ 2%) made by focusing helical undulator radiation without monochromatization, and (iii) a precise sample rotation stage to make repetitive measurements. We successfully detected a very weak time-resolved diffraction signal by using this system from 100-nm-thick Ge2Sb2Te5 phase-change layers. This enabled us to find the dependence of the crystal-amorphous phase change process of the Ge2Sb2Te5 layers on laser power.

  1. Qualitative investigation of fresh human scalp hair with full-field optical coherence tomography

    Science.gov (United States)

    Choi, Woo June; Pi, Long-Quan; Min, Gihyeon; Lee, Won-Soo; Lee, Byeong Ha

    2012-03-01

    We have investigated depth-resolved cellular structures of unmodified fresh human scalp hairs with ultrahigh-resolution full-field optical coherence tomography (FF-OCT). The Linnik-type white light interference microscope has been home-implemented to observe the micro-internal layers of human hairs in their natural environment. In hair shafts, FF-OCT has qualitatively revealed the cellular hair compartments of cuticle and cortex layers involved in keratin filaments and melanin granules. No significant difference between black and white hair shafts was observed except for absence of only the melanin granules in the white hair, reflecting that the density of the melanin granules directly affects the hair color. Anatomical description of plucked hair bulbs was also obtained with the FF-OCT in three-dimensions. We expect this approach will be useful for evaluating cellular alteration of natural hairs on cosmetic assessment or diagnosis of hair diseases.

  2. Investigation of Coherent Multicarrier Code Division Multiple Access for Optical Access Networks

    Directory of Open Access Journals (Sweden)

    Ali Tamini

    2016-01-01

    Full Text Available Orthogonal frequency division multiplexing (OFDM has proved to be a promising technique to increase the reach and bit rate both in long‑haul communications and in passive optical networks. This paper, for the first time, investigates the use of OFDM combined with electrical CDMA in presence of coherent detection as a multiple access scheme. The proposed multicarrier‑CDMA system is simulated using Walsh‑Hadamard codes and its performance is compared to that of coherent WDM-OFDM system in terms of bit‑error‑rate and bandwidth efficiency. It is shown that MC‑CDMA benefits from better spectral efficiency while its performance slightly deteriorates in comparison to WDM-OFDM when the number of users is increased.

  3. Systematically investigating the polarization gradient cooling in an optical molasses of ultracold cesium atoms

    International Nuclear Information System (INIS)

    We systematically investigate the polarization gradient cooling (PGC) process in an optical molasses of ultracold cesium atoms. The SR mode for changing the cooling laser, which means that the cooling laser frequency is stepped to the setting value while its intensity is ramped, is found to be the best for the PGC, compared with other modes studied. We verify that the heating effect of the cold atoms, which appears when the cooling laser intensity is lower than the saturation intensity, arises from insufficient polarization gradient cooling. Finally, an exponential decay function with a statistical explanation is introduced to explain the dependence of the cold atom temperature on the PGC interaction time. (atomic and molecular physics)

  4. Theoretical Investigation of Nonlinear Optical Properties of Organic and Transition Metal Hybrid Azobenzene Dendrimers

    Institute of Scientific and Technical Information of China (English)

    LIU Cai-Ping; LIU Ping; WU Ke-Chen

    2008-01-01

    In this work, we report a theoretical exploration of the responses of organic azo-benzene dendrimers. The polarizabilities, the first and second hyperpolarizabilities of the azobenzene monomers (GO), and the first, second and third generation (G1, G2 and G3, respectively) are investigated by semi-empirical methods. The calculated results show that the nonlinear optical (NLO)properties of these organic dendrimers are mainly determined by the azobenzene chromospheres.Additionally, the values of β and γ increase almost in proportion to the number of chromophores. On the other hand, two types of transition metal hybrid azobenzene dendrimers (core-hybrid and branch-end hybrid according to the sites combined with transition metals) are simulated and discussed in detail in the framework of time-dependent density functional theory (TDDFT). The calculated results reveal that the NLO responses of these metal dendrimers distinctly varied as a result of altering the charge transfer transition scale and the excitation energies.

  5. Investigating the growth mechanism and optical properties of carbon-coated titanium dioxide nanoparticles

    KAUST Repository

    Anjum, Dalaver H.

    2013-10-01

    TiO2 nanoparticles (NPs) were prepared using flame synthesis and then characterized using transmission electron microscopy. We found that the flame method yields both crystalline TiO2 and amorphous TiO 2 NPs. TEM analysis revealed that only the crystalline TiO 2 NPs were coated with carbon. Based on this observation, we proposed a growth model for the diffusion and precipitation of carbon atoms in TiO 2 NPs. The optical properties of TiO2 NPs were investigated by performing valence electron energy loss spectrometry analysis. We observed that carbon-coated TiO2 NPs have higher absorption in the visible range due to their lower band-gap energy. © 2013 Elsevier B.V.

  6. Investigation of Optical Flow Techniques for Extracting Non-Rigid Sea Surface Currents

    Science.gov (United States)

    Ghalenoei, E.; Sharifi, M. A.; Hasanlou, M.

    2014-10-01

    This paper is about performance evaluation of two optical flow (OF) methods for extracting sea surface curved motions like eddies. By incorporating a simple matrix and its rotation in programming procedure, curved motion can be obtained. These two OF methods are Horn/Schunk and Lucas/Kanade. The Horn/Schunk method depends on a smoothness parameter (α) and when it changes, smoothness and reality change too. The Lucas/Kanade method is more complex than previous one. It depends on two parameters, smoothness parameter (Sigma) and window size (Win). Different values for Win and Sigma change smoothness and reality of the flows. Sea surface currents are extracted from two sequential sea surface temperature (SST) images by using OF methods. By using these methods and selecting the appropriate parameters like smoothness (for Horn/Schunk) and window size and smoothness (for Lucas/Kanade) extracting real flows or smooth flows are possible and investigated in this paper.

  7. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  8. Investigations on optical, structural and thermal properties of phosphate glasses containing terbium ions

    International Nuclear Information System (INIS)

    Aluminophosphate glasses belonging to the Li2O–BaO–Al2O3– La2O3–P2O5 system doped with Tb3+ were prepared and investigated. Methods as Induced Coupled Plasma-Mass Spectrometry (ICP-MS), Induced Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) and X-ray diffraction (XRD) have been used to establish the elemental composition of these vitreous materials. The influence of the Tb3+ ions on the optical properties of the phosphate glasses has been investigated in relation with the structural characteristics of the vitreous matrix. The optical behavior has been studied by ultra-violet-visible (UV–Vis) spectroscopy, revealing electronic transitions specific for terbium ions. Fluorescence spectroscopy measurements have been performed by excitation in the UV and visible domains (377 nm and 488 nm) which resulted in the most significant fluorescence peaks in the Vis domain (540 and 547 nm). Structural information via vibration modes were provided by Fourier Transform Infrared (FTIR) absorption spectra in the 400–4000 cm−1 range. Absorption peaks specific for the vitreous phosphate matrix were put in evidence as P-O-P symmetrical and asymmetrical stretching vibration modes, P-O-P bend, PO2- symmetrical and asymmetrical stretching vibration modes, P=O stretching vibration mode as well as P-O-H water absorbance. Raman spectra acquired in the 100–4000 cm−1 range by 488, 514 and 633 nm laser excitation sources disclosed peaks also specific for the phosphate matrix, proving the role of phosphorous oxide as a vitreous network former. Differential Scanning Calorimetry and Thermogravimetric Analysis (DSC-TGA) provided information regarding the phase transformations that took place during the heating process and the associated thermal effects

  9. Radiographic, microcomputer tomography, and optical coherence tomography investigations of ceramic interfaces

    Science.gov (United States)

    Sinescu, Cosmin; Negrutiu, Meda Lavinia; Ionita, Ciprian; Topala, Florin; Petrescu, Emanuela; Rominu, Roxana; Pop, Daniela Maria; Marsavina, Liviu; Negru, Radu; Bradu, Adrian; Rominu, Mihai; Podoleanu, Adrian Gh.

    2010-12-01

    Imagistic investigation of the metal-ceramic crowns and fixed partial prostheses represent a very important issue in nowadays dentistry. At this time, in dental office, it is difficult or even impossible to evaluate a metal ceramic crown or bridge before setting it in the oral cavity. The possibilities of ceramic fractures are due to small fracture lines or material defects inside the esthetic layers. Material and methods: In this study 25 metal ceramic crowns and fixed partial prostheses were investigated by radiographic method (Rx), micro computer tomography (MicroCT) and optical coherence tomography (OCT) working in Time Domain, at 1300 nm. The OCT system contains two interferometers and one scanner. For each incident analysis a stuck made of 100 slices was obtain. These slices were used in order to obtain a 3D model of the ceramic interface. Results: RX and MicroCT are very powerful instruments that provide a good characterization of the dental construct. It is important to observe the reflections due to the metal infrastructure that could affect the evaluation of the metal ceramic crowns and bridges. The OCT investigations could complete the imagistic evaluation of the dental construct by offering important information when it is need it.

  10. Investigation of an optical method for determining the average radius of curvature of micro-optical lenticular lens arrays

    DEFF Research Database (Denmark)

    Iversen, Theis Faber Quist; Hanson, Steen Grüner; Kirkegaard, Peter

    2009-01-01

    Micro-optical elements are of great importance in areas of optoelectronics and information processing. Establishing fast, reliable methods for characterization and quality control of these elements is important in order to maintain the optical performance in a high volume production process. We...... obtained in the far field of surface reflections resulting from a plane wave incident on the lenticular array. The intensity distribution of the diffraction orders is highly correlated with the shape of the illuminated lenslets. This is exploited to attain information about possible defects and shape...

  11. Raman spectroscopic investigation of the confined optical phonon modes in the aligned CdSe nanorod arrays

    Science.gov (United States)

    Nobile, Concetta; Carbone, Luigi; Kudera, Stefan; Manna, Liberato; Cingolani, Roberto; Krahne, Roman; Fonoberov, Vladimir A.; Balandin, Alexander A.; Chilla, Gerwin; Kipp, Tobias; Heitmann, Detlef

    2007-03-01

    Nanocrystal rods have emerged as promising nanostructured material for both fundamental studies of nanoscale effects and for optical and electronic device applications. We investigated the optical phonon excitations in laterally aligned CdSe nanocrystal rod arrays using resonant Raman scattering. Electric-field mediated alignment between interdigitated electrodes has been used to prepare the samples. We report Raman experiments that probe the optical lattice vibrations in ordered arrays of CdSe nanorods with respect to the nanorod orientation. The packing of nanorods into dense arrays leads to the suppression of the surface optical phonon modes. In the longitudinal-optical phonon peak we observe a fine structure that depends on the relative orientation of the nanorods with respect to the incident light polarization. Detailed comparison of the experimental data with the first-principle calculations for corresponding nanostructures, which reveal the symmetry of the phonon potentials for the Raman active modes, provides a qualitative explanation of the experimentally observed phonon modes.

  12. Optical investigation of the metal-insulator transition in $FeSb_2$

    OpenAIRE

    Perucchi, A.; Degiorgi, L.; Hu, R.; Petrovic, C.; Mitrovi{ć}, V.

    2005-01-01

    We present a comprehensive optical study of the narrow gap $FeSb_2$ semiconductor. From the optical reflectivity, measured from the far infrared up to the ultraviolet spectral range, we extract the complete absorption spectrum, represented by the real part $\\sigma_1(\\omega)$ of the complex optical conductivity. With decreasing temperature below 80 K, we find a progressive depletion of $\\sigma_1(\\omega)$ below $E_g\\sim 280$ cm$^{-1}$, the semiconducting optical gap. The suppressed (Drude) spec...

  13. Spectroscopic and quantum-chemical investigation of association of ions in acetonitrile - LiX (X=I, ClO4, NCS) systems

    International Nuclear Information System (INIS)

    Data on association constants of ions in acetonitrile-salt binary systems, obtained from the data on intensity of IR absorption bands of acetonitrile (Acn) molecules contained in solvate shells of Li+ cations, have been analyzed. Using the CCP MO LCAO semiempirical method in the PPDP approximation, electronic structure of acetonitrile molecule and AcnkLi+ and AcnmLi+X- complexes has been studied. It is ascertained that relative stability of ionic pairs Acn3Li+X-, estimated by the squares of their dipole momenta (characterizing solvation energy) increases in the series X=I, ClO4, NCS in agreement with data of spectroscopic experiment, according to which the constant of ion association for LiNCS solution in acetonitrile is much higher than for the systems CH3CN-LiI and CH3CN-LiClO4. 13 refs.,2 figs., 2 tabs.64

  14. Experimental investigation of the chemistry of excited states of rare gases. First quarterly progress report, 15 October 1978--15 January 1979. [Kr* + Cl/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Setser, D.W.

    1979-03-01

    Analysis of XeF(B) and XeF(C) state quenching from photodissociation of XeF/sub 2/ was continued and progress was made on reactive quenching of the resonance states, Xe(/sup 3/P/sub 1/) and Kr(/sup 3/P/sub 1/). The study of the reactions of the resonance states of the rare gases was concentrated on the Kr* + Cl/sub 2/ reaction.

  15. Leaching of a simulated ZnCl2-rich radwaste stabilized with calcium sulfo-aluminate cement: experimental investigation and first attempt of modelling

    International Nuclear Information System (INIS)

    This paper reports the first leaching experiments performed on a simulated ZnCl2-rich waste stabilized with calcium sulfo-aluminate cement according to a standard test developed to understand and model the degradation processes of the cement paste. A simulated cemented waste form (cement paste prepared with a binder containing 20% gypsum and a 0.5 mol/L ZnCl2 mixing solution, and submitted to a thermal cycle at early age simulating the temperature rise and fall occurring in a 200 L drum of cemented waste) was submitted to leaching by pure water (fixed pH of 7) for 3 months. The cumulative quantities of Ca2+, OH-, Cl- and SO42- ions in the leachates increased linearly versus the square root of time, showing that leaching was controlled by diffusion. Zinc was never detected, showing the excellent confining properties of the cement matrix. Examination of the solid sample at the end of the experiment revealed three zones: (i) the highly porous and friable surface layer, composed of aluminum hydroxide, perovskite and probably C-(A)-S-H (thickness: 700 μm), (ii) a less porous intermediate zone in which several precipitation and dissolution fronts occurred (thickness: 1800 μm), and (iii) the sound core. The hydrated phase evolution along depth was qualitatively reproduced with a model coupling transport by diffusion and chemical reactions. (authors)

  16. Optical clearing effect on gastric tissues immersed with biocompatible chemical agents investigated by near infrared reflectance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Xu Xiangqun [Institute of Bioscience and Technology, Cranfield University at Silsoe, Bedfordshire MK45 4DT (United Kingdom); Wang Ruikang [Institute of Bioscience and Technology, Cranfield University at Silsoe, Bedfordshire MK45 4DT (United Kingdom); Elder, James B [Department of Surgery, North Staffordshire Hospital, Stoke-on-Trent ST4 7QB (United Kingdom)

    2003-07-21

    In order to understand the role of water desorption in optical clearing effect on gastric tissues after the application of hyperosmotic agents, dynamics of water loss in porcine stomach administrated with glycerol was investigated with the near infrared reflectance spectroscopy. It is found that the progress of optical clearing of various samples corresponds very well with the individual pattern of water desorption. The changes in optical properties are almost linear with time in frozen-thawed cardiac mucosa immersed in 80% glycerol whilst the water inside the tissue is displaced at the same rate. For the same samples immersed in 50% glycerol, after 30 min, when the dehydration equilibrates with time, optical clearing tends to lever out. The overall water loss in frozen porcine stomach at 60 min after the immersion of 80% and 50% glycerol is approximately 38% and 13%, respectively. The more significant effect of optical clearing by 80% glycerol is due to its high refractive index and high dehydration capability. In fresh pyloric mucosa samples, treated with 50% glycerol through the topical application, the changes of optical properties at the initial stage are very slow due to the mucous barrier. However, once the solution has penetrated into tissue, optical clearing is achieved significantly with time. The results indicate that optical clearing induced by hyperosmotic agents is strongly correlated with dehydration.

  17. Elements of fiber-optic communication lines and methods for their investigation

    Science.gov (United States)

    Belovolov, M. I.; Kriukov, A. P.; Kuznetsov, A. V.; Pencheva, V. Kh.

    Experimental results are presented on optical feedback effects arising during the matching of semiconductor lasers with single-mode fiber-optic waveguides. It is shown that matching elements such as focusing concentrators and microobjectives can be used in high-speed fiber-optic lines with direct detection, while microobjectives with obligatory monitoring of their effect on the width of the laser-action line should be used in coherent fiber-optic lines. Based on this approach, a simple fiber-optic Michelson interferometer has been constructed with a discretely variable arm difference and a novel scheme of visibility recording.

  18. Three-dimensional simultaneous optical coherence tomography and confocal fluorescence microscopy for investigation of lung tissue

    Science.gov (United States)

    Gaertner, Maria; Cimalla, Peter; Meissner, Sven; Kuebler, Wolfgang M.; Koch, Edmund

    2012-07-01

    Although several strategies exist for a minimal-invasive treatment of patients with lung failure, the mortality rate of acute respiratory distress syndrome still reaches 30% at minimum. This striking number indicates the necessity of understanding lung dynamics on an alveolar level. To investigate the dynamical behavior on a microscale, we used three-dimensional geometrical and functional imaging to observe tissue parameters including alveolar size and length of embedded elastic fibers during ventilation. We established a combined optical coherence tomography (OCT) and confocal fluorescence microscopy system that is able to monitor the distension of alveolar tissue and elastin fibers simultaneously within three dimensions. The OCT system can laterally resolve a 4.9 μm line pair feature and has an approximately 11 μm full-width-half-maximum axial resolution in air. confocal fluorescence microscopy visualizes molecular properties of the tissue with a resolution of 0.75 μm (laterally), and 5.9 μm (axially) via fluorescence detection of the dye sulforhodamine B specifically binding to elastin. For system evaluation, we used a mouse model in situ to perform lung distension by application of different constant pressure values within the physiological regime. Our method enables the investigation of alveolar dynamics by helping to reveal basic processes emerging during artificial ventilation and breathing.

  19. Color Shift Investigations for LED Secondary Optical Designs: Comparison between BPA-PC and PMMA

    Science.gov (United States)

    Lu, Guangjun; Yazdan Mehr, M.; van Driel, W. D.; Fan, Xuejun; Fan, Jiajie; Jansen, K. M. B.; Zhang, G. Q.

    2015-07-01

    Recently, color shift of LED-based lighting products has attracted much attention due to its increasing impact on the field application. However, significant research investigations on the color shift mechanisms are not publically available especially for important transmission materials used for secondary optical design. In this paper, broadly used such commercial materials (BPA-PC and PMMA) are experimentally investigated on the color shift effects during aging. Besides this, color shift mechanisms of degradation of transmittance are also studied. Results revealed: (1) Inconsistent degradation of wavelength-dependent transmittance induces the decrease of the blue/yellow light intensity ratio and thus gives rise to the color shift toward the yellow field, which is the color shift mechanism of BPA-PC; (2) Even for the non-aged BPA-PC, the transmittance varies with wavelength in the visible light field due to the chemistry of the material, which caused the change of intensify ratio of blue light to yellow light in the SPD, leading to color change in perception; (3) Oxidation plays a key role in the degradation of transmittance at around the peak wavelength of the blue light field, which is in correlation with the discoloration of thermally-aged BPA-PC materials. By contrast, for the PMMA specimen aged up to 3000 h, oxidation was neither occurred at 85 °C, nor with additional exposure to blue light, nor even with additional humidity of 85%RH.

  20. Linear and Nonlinear Optical Response in Silver Nanoclusters: Insight from a Computational Investigation.

    Science.gov (United States)

    Day, Paul N; Pachter, Ruth; Nguyen, Kiet A; Bigioni, Terry P

    2016-02-01

    We report a density functional theory (DFT) and time-dependent DFT (TDDFT) investigation of the thiolated silver nanoclusters [Ag44(SR)30](4-), Ag14(SR)12(PR'3)8, Ag31(SG)19, Ag32(SG)19, and Ag15(SG)11, which were synthesized and for which one-photon absorption (OPA) characterization is available. Our computational investigation based on careful examination of the exchange-correlation functional used in DFT geometry optimization and for the linear optical properties predictions by TDDFT, demonstrated good agreement with the measured linear absorption spectra, however dependent on the applied functional. Following the benchmarking, we evaluated the two-photon absorption (TPA) response using TDDFT, noting that accurate prediction of OPA is important for suppositions on the spectral range for TPA enhancement because of the sensitivity to the excitation energies. Although the TPA cross-section results are complicated by resonance effects and quantifying TPA cross sections for these systems is difficult, our results indicate that the nanoclusters Ag15 and Ag31/32 are likely to have large TPA cross sections. The spherical symmetry of the Ag44 and Ag14 nanoclusters leads to applicability of superatom theory, while it is not as useful for the more oblate geometries of the Ag15 and Ag31/32 systems. PMID:26730764

  1. Gas Bubbles Investigation in Contaminated Water Using Optical Tomography Based on Independent Component Analysis Method

    Directory of Open Access Journals (Sweden)

    Mohd Taufiq Mohd Khairi

    2016-01-01

    Full Text Available This paper presents the results of concentration profiles for gas bubble flow in a vertical pipeline containing contaminated water using an optical tomography system. The concentration profiles for the bubble flow quantities are investigated under five different flows conditions, a single bubble, double bubbles, 25% of air opening, 50% of air opening, and 100% of air opening flow rates where a valve is used to control the gas flow in the vertical pipeline. The system is aided by the independent component analysis (ICA algorithm to reconstruct the concentration profiles of the liquid-gas flow. The behaviour of the gas bubbles was investigated in contaminated water in which the water sample was prepared by adding 25 mL of colour ingredients to 3 liters of pure water. The result shows that the application of ICA has enabled the system to detect the presence of gas bubbles in contaminated water. This information provides vital information on the flow inside the pipe and hence could be very significant in increasing the efficiency of the process industries.

  2. Space stability investigations of optical coatings by earth- and space-based experiments

    Science.gov (United States)

    Hacker, Erich; Weissbrodt, P.; Raupach, L.; Lauth, Hans; Kappel, H.; Wagner, S.; Schmitt, Dirk-Roger

    1994-09-01

    Optical components for space optics - especially coated optical elements which represent the external surfaces of optical space instrumentation - have to work under harsh operation conditions like thermal loads, irradiation by photons, electrons and protons, as well as in atomic oxygen environments at low earth orbits. Additionally they have to withstand other cross contamination coming from the spacecraft. Therefore, the stability against these influences is a decisive factor for the application performance of optical coatings in space-borne devices. Some very recent results, based on the Surface Effects Sample Monitor (SESAM) flight experiment carried out aboard the ORFEUS-Shuttle Pallet Satellite (SPAS), STS-51, Discovery, are presented here along with laboratory experiments in an UHV-surface analysis system. The topics include ground simulation of selective and complex particle bombardment of optical coating analyzed by XPS as well as the verification of these results by flight experiments in combination with optical measurements (transmission, scattering).

  3. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  4. Theoretical Investigation on Structures and Nonlinear Optical Properties of the Alkalis and Low Coordination Acenes Salt

    International Nuclear Information System (INIS)

    The alkalis and low coordination acenes salts alpha-M at the rate of n-acenes (M = Li, Na and K) salts (n = 1, 2 and 3) were designed to investigate the effect of the increasing atomic number of alkali metals and the number n of conjugated benzenoid rings on the nonlinear optical responses. Alkalis Li, Na and K were selected herein, and both DFT (M05-2X, M06-2X and PBE0) and MP2 methods and 6-311+G(D) basis set are employed to optimize geometrical structures and to calculate the polarizability (alpha/sub 0/) and first hyperpolarizability (beta/sub vec/) of the alpha-M at the rate of n-acenes (M = Li, Na and K) salts (n = 1, 2 and 3). Results show that the alpha/sub 0/ values of alpha-M at the rate of n-acenes (M = Li, Na and K) salts (n = 1, 2 and 3) increase with increasing number of n conjugated benzenoid rings and the atomic number of alkali metals and beta/sub vec/ values of alpha-M at the rate of n-acenes (M = Li, Na and K) salts (n = 1, 2 and 3) are opposite. The beta/sub vec/ values of alpha-M at the rate of n-acenes (M = Li, Na and K) salts (n = 1, 2 and 3) are increasing remarkably (397.6 au. for alpha-Li at the rate of benzene < 1196.5 au. for alpha-Na at the rate of benzene < 1608.6 au. for alpha-K at the rate of benzene and tending to decease with increasing number of n by M06-2X method. Our present research may be favorable to the development of excellent nonlinear optical (NLO) materials. (author)

  5. Investigation of code reconfigurable fibre Bragg gratings for Optical Code Division Multiple Access (OCDMA) and Optical Packet Switching (OPS) Networks

    OpenAIRE

    Tian, Chun

    2009-01-01

    This thesis documents my work in the telecommunication system laboratory at the Optoelectronics Research Centre, towards the implementation of code reconfigurable OCDMA and all-optical packet switching nodes based on fibre Bragg grating (FBG) technology. My research work involves characterizing the performance of various gratings, specifically high reflectivity, short chip duration, long code sequences, multiple phase level and tunable superstructured fiber Bragg gratings (SSFBGs), by using t...

  6. Reactions Between Humic Acid Solutions and Excessive ClO2 or Cl2

    Institute of Scientific and Technical Information of China (English)

    GE Yuan-xin; ZHU Zhi-liang; MA Hong-mei; ZHAO Jian-fu

    2007-01-01

    Reactions between humic acid solutions and excessive ClO2 or Cl2 have been investigated. Under various experimental conditions, the removal efficiency of TOC, UV254 and A140 from humic acid solutions were examined. The relationship between the removal efficiency and the consumption of ClO2 or Cl2 was discussed. The results showed that the maximum demand of ClO2 was 2.19 mg/mg TOC for the humic acid solution under the experimental conditions, and that of Cl2 was 1.88 mg/mg TOC. The variation tendency of ClO2 consumption was similar to that of Cl2. TOC of humic acid solutions decreased 15.2% and 15.6% after the reaction with ClO2 or Cl2 respectively. Under the experimental conditions, 21.4% of unsaturated bonds and 52.8% of humic acid color were removed by ClO2 in 168 h. As for Cl2, removal efficiency of unsaturated bonds and humic acid color were 16.8% and 41.7% respectively. Larger molecules from humic acid were oxidized to smaller molecules by ClO2 and Cl2. Higher oxidation potential of ClO2 than that of Cl2 was also indicated by variation of UV254/A410 ratios. The similar tendency, that exhibited faster variation in the initial 24 h, existed for all the research factors.

  7. Development of a scanning nearfield optical microscope for low-temperature investigations of semiconductor nanostructures

    International Nuclear Information System (INIS)

    In the present work the electronic structure of MOCVD-grown InGaAs/GaAs and InAs/GaAs quantum dots which are characterized by a particularly low ground state transition energy, was investigated using Scanning Nearfield Optical Microscopy (SNOM). The pivotal question of the presented investigations is, which influence the interaction of the confined carriers has on the energy states of the biexcitons and the multiexcitons in a quantum dot. Therefore, photoluminescence spectra of single quantum dots were investigated under varying excitation intensity at different temperatures between 5 K and 300 K. The construction of a novel scanning nearfield microscope especially for low temperatures allowed the investigation of single quantum dots. Due to significant improvements of the positioning technology and the shear-force distance control between the sample and the nearfield probe a stable scanning of the quantum dot samples at 5 K could be demonstrated, showing a lateral optical resolution of 200 nm. This way, in the photoluminescence spectroscopy of single quantum dots the thermal linewidth broadening of the detected light was reduced down to a value of less than 1 meV, which allowed the identification of the transitions of biexcitons and multiexcitons. On the basis of the performed measurements, for the InGaAs/GaAs quantum dots a biexciton state was identified, with variable binding energies of 2-7 meV. Furthermore, a positively charged trion state with a binding energy of 11 meV was observed, showing high emission intensity, which can be assigned to the sample doping. Accordingly, for the positively charged biexciton state a binding energy of 11 meV can be announced. For the investigated InAs/GaAs quantum dots a biexciton state with binding energies of 3-4 meV was found. Some of the investigated InAs/GaAs quantum dots showed the formation of positively charged states, in particular of a trion state with a binding energy of 3 meV, and of the positively charged

  8. Development of a scanning nearfield optical microscope for low-temperature investigations of semiconductor nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Hodeck, Kai Friedrich

    2009-02-19

    In the present work the electronic structure of MOCVD-grown InGaAs/GaAs and InAs/GaAs quantum dots which are characterized by a particularly low ground state transition energy, was investigated using Scanning Nearfield Optical Microscopy (SNOM). The pivotal question of the presented investigations is, which influence the interaction of the confined carriers has on the energy states of the biexcitons and the multiexcitons in a quantum dot. Therefore, photoluminescence spectra of single quantum dots were investigated under varying excitation intensity at different temperatures between 5 K and 300 K. The construction of a novel scanning nearfield microscope especially for low temperatures allowed the investigation of single quantum dots. Due to significant improvements of the positioning technology and the shear-force distance control between the sample and the nearfield probe a stable scanning of the quantum dot samples at 5 K could be demonstrated, showing a lateral optical resolution of 200 nm. This way, in the photoluminescence spectroscopy of single quantum dots the thermal linewidth broadening of the detected light was reduced down to a value of less than 1 meV, which allowed the identification of the transitions of biexcitons and multiexcitons. On the basis of the performed measurements, for the InGaAs/GaAs quantum dots a biexciton state was identified, with variable binding energies of 2-7 meV. Furthermore, a positively charged trion state with a binding energy of 11 meV was observed, showing high emission intensity, which can be assigned to the sample doping. Accordingly, for the positively charged biexciton state a binding energy of 11 meV can be announced. For the investigated InAs/GaAs quantum dots a biexciton state with binding energies of 3-4 meV was found. Some of the investigated InAs/GaAs quantum dots showed the formation of positively charged states, in particular of a trion state with a binding energy of 3 meV, and of the positively charged

  9. Optical and MRI investigations of an optimized acrylamide-based polymer gel dosimeter

    International Nuclear Information System (INIS)

    The first purpose of this research was improvement of sensitivity of the normoxic acrylamide-based polymer gel dosimeter. Another aim of this study was investigation of the absorbance of the irradiated gels as well as their relaxation rate variations. In addition, a new optical parameter, area under the absorbance spectrum (AUS), was investigated. Sensitivity improvement was performed by adding glucose and urea to the previously reported acrylamide-based polymer gel formulation and new formulation was named PAGATUG. The formulation which gives the nearest tissue elemental composition has been determined to be 3 % bis, 3 % AA, 5 % gelatine, 5 mM THPC, 0.01 mM HQ, 8.5 % glucose, and 3 % urea. The differences in electron density, number of electrons per gram and effective atomic number of PAGATUG gel were no more than 1, 0.5, and 0.8 % of the corresponding values for the soft tissue respectively. PAGATUG gels were irradiated by 60Co radiotherapy unit photon beams with different doses and imaged using a 1.5T Siemens Avanto MRI scanner for different post irradiation times. In addition, the absorbance of the irradiated gels were evaluated using a double beam spectrophotometer. We found that the R2-sensitivity of polymer gel was improved by a factor of more than 2.6 in respect of the previously reported PAGAT polymer gel. Dose-absorbance sensitivity was obtained as 0.89 Au Gy-1 and the results showed more stable response in respect of R2 investigation. An AUS-sensitivity of 107.7 Au nm Gy-1 indicated to steep response variation. This read out parameter showed an acceptable linearity and dynamic dose range. (author)

  10. Investigating quartz optically stimulated luminescence dose-response curves at high doses

    Energy Technology Data Exchange (ETDEWEB)

    Lowick, Sally E., E-mail: lowick@geo.unibe.c [Institut fuer Geologie, Universitaet Bern, Baltzerstrasse 1-3, 3012 Bern (Switzerland); Preusser, Frank [Institut fuer Geologie, Universitaet Bern, Baltzerstrasse 1-3, 3012 Bern (Switzerland); Wintle, Ann G. [Institute of Geography and Earth Sciences, Aberystwyth University, AberystwythSY23 3DB (United Kingdom)

    2010-10-15

    Despite the general expectation that optically stimulated luminescence (OSL) growth should be described by a simple saturating exponential function, an additional high dose component is often reported in the dose response of quartz. Although often reported as linear, it appears that this response is the early expression of a second saturating exponential. While some studies using equivalent doses that fall in this high dose region have produced ages that correlate well with independent dating, others report that it results in unreliable age determinations. Two fine grain sedimentary quartz samples that display such a response were used to investigate the origin of this additional high dose component: three experiments were conducted to examine their dose-response up to >1000 Gy. The high dose rates provided by laboratory irradiation were found not to induce a sensitivity change in the response to a subsequent test dose, with the latter not being significantly different from those generated following naturally acquired doses. The relative percentage contributions of the fast and medium OSL components remained fixed throughout the dose-response curve, suggesting that the electron traps that give rise to the initial OSL do not change with dose. An attempt was made to investigate a change in luminescence centre recombination probability by monitoring the depletion of the '325 {sup o}C' thermoluminescence (TL) during the optical stimulation that would result in depletion of the OSL signal. The emissions measured through both the conventional ultraviolet (UV), and a longer wavelength violet/blue (VB) window, displayed similar relative growth with dose, although it was not possible to resolve the origin of the VB emissions. No evidence was found to indicate whether the additional component at high doses occurs naturally or is a product of laboratory treatment. However, it appears that these samples display an increased sensitivity of quartz OSL to high doses

  11. Optical label encoding using electroabsorption modulators and investigation of chirp properties

    DEFF Research Database (Denmark)

    Xu, Lin; Chi, Nan; Oxenløwe, Leif Katsuo;

    2003-01-01

    A novel scheme of optical label encoding by wavelength conversion based on electroabsorption modulators (EAMs) is reported. Based on the experimental observations, the chirp properties of the wavelength-converted signal are discussed and a wide dynamic range of the chirp α-parameter is found allo...... allowed. Compared with cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA), the EAM has several advantages, which make it attractive for optical label encoding or other applications as a wavelength converter....

  12. Investigation of a low-cost optical-CT system with minimal refractive index-matching fluid

    International Nuclear Information System (INIS)

    Optical computed tomography (optical-CT) is a method for visualizing 3dimensional dose distributions in radiochromic dosimeters. Projection images are acquired by collimating a visible light point source into parallel-beam geometry and imaging differential absorption through the sample dosimeter. Practical challenges involved in optical-CT imaging were addressed through the investigation of an in-house Fresnel-based optical-CT system with considerably less refractive index-matching fluid. The ''DFOS'' (Duke Fresnel-based Optical- CT System) system differed from current optical-CT systems by replacing cumbersome convex telecentric lenses with a lighter and much less expensive Fresnel system. A second major modification was the replacement of the refractive index-matching fluid bath with a solid polyurethane tank. PRESAGE radiochromic dosimeters were irradiated with orthogonal parallel-opposed treatments and dose distributions were readout by the DFOS system and compared to both treatment planning software prediction and two other in-house optical-CT systems. Gamma index passing rate at the 3%/3mm threshold in relation to Eclipse treatment planning software for the treatment was 92.2%%, compared to 96.8% and 95.6% for two other systems featuring a traditional setup. The DFOS system showed promise for 3D dosimetry, but the performance is still substantially inferior at present to the gold-standard systems

  13. Investigation of the limits of a fibre optic sensor system for measurement of temperature distribution

    DEFF Research Database (Denmark)

    Brehm, Robert; Johnson, Frank

    2006-01-01

    The aim of this project is to develop an innovative temperature sensor system which is able to measure the temperature distribution along a fibre optical cable. This technique for temperature measurement is based on Optical Time Domain Reflectometry (OTDR). ©2006 IEEE.......The aim of this project is to develop an innovative temperature sensor system which is able to measure the temperature distribution along a fibre optical cable. This technique for temperature measurement is based on Optical Time Domain Reflectometry (OTDR). ©2006 IEEE....

  14. Investigation on the influence of intensity scintillation and beam wander in space optical uplink DWDM communication system

    Science.gov (United States)

    Li, Mi; Chen, Mengji; Zhang, Xuping; Cong, Hengji; Song, Yuejiang; Lu, Yuangang

    2016-04-01

    Dense wavelength division multiplexing (DWDM) has been widely applied in ground optical communication. However, the technology of DWDM is still not mature enough in the space optical communication system. In order to further advance the use of DWDM into space optical communication, the probability density function (PDF) and the bit-error rate (BER) performance of DWDM is investigated in uplink communications under the influence of atmospheric turbulence, consisting of intensity scintillation and beam wander caused by atmospheric turbulence. Numerical results show that the atmospheric turbulence has a great impact on BER and PDF, and wavelength, divergence angel, and other relevant parameters should be carefully considered in this DWDM system. This work can be conducive for improving DWDM design of space optical uplink communication systems.

  15. Magnetization and Specific Heat Investigations of the Bose Glass: Br-doped NiCl2-4SC(NH2)2

    Science.gov (United States)

    Weickert, Franziska; Miclea, Corneliu; Movshovich, Roman; Zapf, Vivien; Yu, Rong; Roscilde, Tommaso

    2012-02-01

    NiCl2-4SC(NH2)2 (DTN) is an insulating material, which shows field induced XY-AFM order between Hc1 = 2.1 T and Hc2 = 12.6 T. In boson language, the ground state of DTN can be described as a Mott insulator, and the ordered state as a Bose-Einstein condensation of magnons. Bond disorder is introduced by substituting Br atoms on Cl positions, which simultaneously changes the super exchange interaction along the c-direction on a local scale and leads to a Mott-glass ground state in zero field. Furthermore, the system develops a gapless Bose glass for magnetic fields 0 Hc2, followed by a Mott insulating state above the saturation field Hsat. Note, that the critical fields Hc1,2 and Hsat are shifted compared to those of pure DTN. In this talk, we report on measurements of the magnetization and specific heat at very low temperatures between 50 mK and 3 K in high magnetic fields up to 14 T on an 8% Br-doped single crystal DTN. We compare our data with the local gap model, which reduces the low-temperature and low-field behavior to those of an ensemble of individual three level systems with local magnetization MS = 0, ±1 and a finite energy gap for H = 0.

  16. Investigation on a two-stage solar liquid-desiccant (LiBr) dehumidification system assisted by CaCl{sub 2} solution

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Z.Q. [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200240 (China); Dai, Y.J. [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200240 (China)], E-mail: yjdai@sjtu.edu.en; Wang, R.Z. [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2009-04-15

    A two-stage solar powered liquid-desiccant dehumidification system, for which two kinds of desiccant solution (lithium chloride and calcium bromide) are fed to the two dehumidification stages separately, has been studied. In the studied system air moisture (latent) load is separately removed by a pre-dehumidifier using cheap calcium chloride (CaCl{sub 2}) and a main dehumidifier using stable lithium bromide (LiBr). Side-effect of mixing heat rejected during dehumidification process is considerably alleviated by an indirect evaporative cooling unit added between the two dehumidification stages. The feasibility of high-desiccant concentration difference achieved by reusing desiccant solution to dehumidify air and regenerating desiccant repeatedly is analyzed. By increasing desiccant concentration difference, desiccant storage capacity is effectively explored. It is found that the pre-dehumidification effect of CaCl{sub 2} solution is significant in high ambient humidity condition. Also seen is that the desiccant investment can be decreased by 53%, though the cost of equipments is somewhat increased, and the Tcop and COP of the proposed system can reach 0.97 and 2.13, respectively.

  17. Investigation on a two-stage solar liquid-desiccant (LiBr) dehumidification system assisted by CaCl2 solution

    International Nuclear Information System (INIS)

    A two-stage solar powered liquid-desiccant dehumidification system, for which two kinds of desiccant solution (lithium chloride and calcium bromide) are fed to the two dehumidification stages separately, has been studied. In the studied system air moisture (latent) load is separately removed by a pre-dehumidifier using cheap calcium chloride (CaCl2) and a main dehumidifier using stable lithium bromide (LiBr). Side-effect of mixing heat rejected during dehumidification process is considerably alleviated by an indirect evaporative cooling unit added between the two dehumidification stages. The feasibility of high-desiccant concentration difference achieved by reusing desiccant solution to dehumidify air and regenerating desiccant repeatedly is analyzed. By increasing desiccant concentration difference, desiccant storage capacity is effectively explored. It is found that the pre-dehumidification effect of CaCl2 solution is significant in high ambient humidity condition. Also seen is that the desiccant investment can be decreased by 53%, though the cost of equipments is somewhat increased, and the Tcop and COP of the proposed system can reach 0.97 and 2.13, respectively

  18. Investigation of structural and optical properties of nanoporous GaN film

    International Nuclear Information System (INIS)

    The structural and optical characteristics of porous GaN prepared by Pt-assisted electroless etching under different etching durations are reported. The porous GaN samples were investigated by scanning electron microscopy (SEM), high-resolution X-ray diffraction (HR-XRD), photoluminescence (PL) and Raman scattering. SEM images indicated that the density of the pores increased with the etching duration; however, the etching duration has no significant effect on the size and shape of the pores. XRD measurements showed that the (0 0 0 2) diffraction plane peak width of porous samples was slightly broader than the as-grown sample, and it increased with the etching duration. PL measurements revealed that the near band edge peak of all the porous samples were red-shifted; however, the porosity-induced PL intensity enhancement was only observed in the porous samples; apart from that, two additional strain-induced structural defect-related PL peaks observed in as-grown sample were absent in porous samples. Raman spectra showed that the shift of E 2 (high) to lower frequency was only found in samples with high density of pores. On the contrary, the absence of two forbidden TO modes in the as-grown sample was observed in some of porous samples

  19. Investigation of optical properties of anthocyanin doped into sol-gel based matrix

    Science.gov (United States)

    Hashim, Hasrina; Abdul Aziz, Nik Mohd Azmi Nik; Isnin, Aishah

    2012-06-01

    Anthocyanin dye was extracted from petal of Hibiscus rosasinensis (Bunga Raya) and doped into sol-gel based matrix to investigate an effect of pH change on its optical properties. Sol-gel matrix based on Vinyl triethoxysilene (VTES) as a precursor was prepared through Sol-gel process at pH 7. The sol was doped with 0.1% of Anthocyanin and the same amount of dye was also dissolved in ethanol as a comparative sample. Hydrochloric Acid, HCl and Tetramethylammonium Hydroxide, TMAH were used to change the pH value by adding them at various concentrations into each sample. The emission spectra and chemical structures of the samples were measured by Spectrofluorometer and Fourier Transform Infrared (FTIR) respectively. When excited at 410 nm, two emission peaks at about 492 and 574 nm were observed for Anthocyanin in acidic environment both in ethanol and VTES sol. In base environment however, only Anthocyanin dissolved in ethanol produced emission peak with a single peak at about 539 nm. The sensitivity of Anthocyanin dye toward pH changes in VTES open a possibility to use it as sensing element in which sol-gel based matrix are known to have higher mechanical strength and thermal stability.

  20. Theoretical Investigations of Nonlinear Optical Properties of Transition Metal Cluster Anions

    Institute of Scientific and Technical Information of China (English)

    LIU Cai-Ping; SA Rong-Jian; MANG Chao-Yong; LI Qiao-Hong; LI Fu-Jun; WU Ke-Chen

    2008-01-01

    In the framework of density functional theory (DFT), the electronic excitations and nonlinear optical (NLO) properties of six binuelear transition metal cluster anions with the formula of [Ch2M-(μ-Ch)2-M'CN]2-(M = Mo, W; Ch = S, Se; M' = Cu, Ag) have been systemically investigated at both cases of gas phase and DMF solution. The obtained electronic absorption spectra reveal that the element replacements of metals M and ligands Ch have significant influence on the absorptions, especially on the low-lying ones. In addition, the transitions of μ-Ch→M are dominant for the low-lying excitations, whereas the transitions of M'→M as well as Ch→M are mainly responsible for the higher excitations. The calculated molecular first and second hyper- polarizabilities present the remarkable element substitution and solvent effects. The analyses show that the transitions involving μ-Ch→M charge transfer make the critical contributions to the first hyperpolarizability β, and that the charge transfers from the moieties of MCh4 to M'CN as well as those of β-Ch→M and M'→M are responsible for the second hyperpolarizability γ. Moreover, the introduction of solvent leads to the results that the transitions within the moieties of MCh4 and M'CN make larger contributions to the hyperpolafizability, especially to γ.

  1. Investigating the choriocapillaris and choroidal vasculature with new optical coherence tomography technologies.

    Science.gov (United States)

    Ferrara, Daniela; Waheed, Nadia K; Duker, Jay S

    2016-05-01

    The body of knowledge of in vivo investigation of the choroid has been markedly enhanced by recent technological advances in optical coherence tomography (OCT). New insights elucidating the morphological features of the choriocapillaris and choroidal vasculature, in both physiological and pathological conditions, indicate that the choroid plays a pivotal role in many posterior segment diseases. In this article, a review of the histological characteristics of the choroid, which must be considered for the proper interpretation of in vivo imaging, is followed by a comprehensive discussion of fundamental principles of the current state-of-the-art in OCT, including cross-sectional OCT, en face OCT, and OCT angiography using both spectral domain OCT and swept source OCT technologies. A detailed review of the tomographic features of the choroid in the normal eye is followed by relevant findings in prevalent chorioretinal diseases, focusing on major causes of vision loss such as typical early and advanced age-related macular degeneration, polypoidal choroidal vasculopathy, central serous chorioretinopathy, pachychoroid spectrum disorders, diabetic choroidopathy, and myopia. PMID:26478514

  2. Experimental investigation of different refining stages influences on optical and ultrasonic signals in paper pulp suspensions

    International Nuclear Information System (INIS)

    An important parameter to control in papermaking is the fiber mass fraction in the pulp suspension. Poor control to an unstable process that compromises the production, quality and the energy efficiency in the pulp mill. Using optical or ultrasound measurement techniques can obtain estimation of the mass fraction. Refining is an important operation in preparing the fibers for the paper machine. Refining influence the properties of the fiber by crushing the fiber, roughens the fiber surface and occasionally cut fibers and removes parts of the outer fiber wall leading to an increasing amount of short fibers (fines). A freeness tester was used for verify the changes in fiber properties at four different refining levels. The result shows that for unbleached softwood pulp the used measurement techniques either were not observable or minor. The results indicate that refining can potentially influence accurate consistency estimation for unbleached softwood pulp but for bleached hardwood pulp the influence is believed to be minor using the investigating measurement techniques

  3. Sol-gel synthesized zinc oxide nanorods and their structural and optical investigation for optoelectronic application

    Science.gov (United States)

    Foo, Kai Loong; Hashim, Uda; Muhammad, Kashif; Voon, Chun Hong

    2014-08-01

    Nanostructured zinc oxide (ZnO) nanorods (NRs) with hexagonal wurtzite structures were synthesized using an easy and low-cost bottom-up hydrothermal growth technique. ZnO thin films were prepared with the use of four different solvents, namely, methanol, ethanol, isopropanol, and 2-methoxyethanol, and then used as seed layer templates for the subsequent growth of the ZnO NRs. The influences of the different solvents on the structural and optical properties were investigated through scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and photoluminescence. The obtained X-ray diffraction patterns showed that the synthesized ZnO NRs were single crystals and exhibited a preferred orientation along the (002) plane. In addition, the calculated results from the specific models of the refractive index are consistent with the experimental data. The ZnO NRs that grew from the 2-methoxyethanol seeded layer exhibited the smallest grain size (39.18 nm), largest diffracted intensities on the (002) plane, and highest bandgap (3.21 eV).

  4. Structural and Optical Investigations of Radiation Damage in Transparent PET Polymer Films

    Directory of Open Access Journals (Sweden)

    Shiv Govind Prasad

    2011-01-01

    Full Text Available Effects of gamma irradiation at different doses up to 135 kGy on polyethylene terephthalate (PET polymer films have been investigated by X-ray diffraction (XRD, Fourier transform infrared (FTIR spectroscopy, and ultraviolet-visible (UV-VIS spectroscopy. From XRD analysis, it was found that even at a high dose of gamma irradiation of 135 kGy, crystallinity of the PET samples remain unchanged. However, the FTIR peak at 871 cm−1 (depicting C–H bending mode of out-of-plane vibration and another at 1303 cm−1 (representing C–H bending mode of in-plane vibration disappear for gamma-irradiated PET. In this study, it has also been found that γ-irradiation in air enhances the optical absorption in the wavelength region 320–370 nm. This has been attributed to free radicals being produced in the polymer by the γ-radiation. Further, the free radicals react with oxygen of air to form carbonyl group and hydroxyls. With increasing γ-dose, there is a red shift of the UV—near visible cutoff for PET. XRD and FTIR observations on γ-damage have been correlated.

  5. Investigating the vortex melting phenomenon in BSCCO crystals using magneto-optical imaging technique

    Indian Academy of Sciences (India)

    A Soibel; S S Banerjee; Y Myasoedov; M L Rappaport; E Zeldov; S Ooi; T Tamegai

    2002-05-01

    Using a novel differential magneto-optical imaging technique we investigate the phenomenon of vortex lattice melting in crystals of Bi2Sr2CaCu2O8 (BSCCO). The images of melting reveal complex patterns in the formation and evolution of the vortex solid–liquid interface with varying field ()/temperature (). We believe that the complex melting patterns are due to a random distribution of material disorder/inhomogeneities across the sample, which create fluctuations in the local melting temperature or field value. To study the fluctuations in the local melting temperature/field, we have constructed maps of the melting landscape m(, ), viz., the melting temperature (m) at a given location () in the sample at a given field (). A study of these melting landscapes reveals an unexpected feature: the melting landscape is not fixed, but changes rather dramatically with varying field and temperature along the melting line. It is concluded that the changes in both the scale and shape of the landscape result from the competing contributions of different types of quenched disorder which have opposite effects on the local melting transition.

  6. Investigations on optical properties of Sm{sup 3+} ion doped boro-phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Vijayakumar, R.; Suthanthirakumar, P.; Karthikeyan, P.; Marimuthu, K., E-mail: mari-ram2000@yahoo.com [Department of Physics, Gandhigram Rural Institute – Deemed University, Gandhigram – 624302 (India)

    2015-06-24

    The Sm{sup 3+} doped Boro-phosphate glasses with the chemical composition 60H{sub 3}BO{sub 3}+20Li{sub 2}CO{sub 3}+10ZnO+(10−x) H{sub 6}NO{sub 4}P+xSm{sub 2}O{sub 3} (where x= 0.1, 0.5, 1 and 2 in wt%) have been prepared by melt quenching technique. The prepared glasses were characterized through optical absorption and luminescence spectral measurements. The band gap energies corresponding to the direct and indirect allowed transitions and the Urbach’s energy values were estimated from the absorption spectra. Judd-Ofelt intensity parameters have been derived to predict the radiative properties of the various emission transitions. In order to identify the emission color of the prepared glasses, the emission intensities were analyzed using CIE 1931 color chromaticity diagram. The energy transfer process takes place between Sm{sup 3+}−Sm{sup 3+} ions through cross-relaxation mechanism have also been investigated and the results were discussed and reported.

  7. Experimental investigation on the high chip rate of 2D incoherent optical CDMA system

    Science.gov (United States)

    Su, Guorui; Wang, Rong; Pu, Tao; Fang, Tao; Zheng, Jilin; Zhu, Huatao; Wu, Weijiang

    2015-08-01

    An innovative approach to realise high chip rate in OCDMA transmission system is proposed and experimentally investigation, the high chip rate is achieved through a 2-D wavelength-hopping time-spreading en/decoder based on the supercontinuum light source. The source used in the experiment is generated by high nonlinear optical fiber (HNLF), Erbium-doped fiber amplifier (EDFA) which output power is 26 dBm, and distributed feed-back laser diode which works in the gain switch state. The span and the flatness of the light source are 20 nm and 3 dB, respectively, after equalization of wavelength selective switch (WSS). The wavelength-hopping time-spreading coder can be changed 20 nm in the wavelength and 400 ps in the time, is consist of WSS and delay lines. Therefore, the experimental results show that the chip rate can achieve 500 Gchip/s, in the case of 2.5 Gbit/s, while keeping a bit error rate below forward error correction limit after 40 km transmission.

  8. Structural and optical investigations of oxygen defects in zinc oxide nanoparticles

    International Nuclear Information System (INIS)

    ZnO nanoparticles (NPs) were prepared implementing chemical precipitation method. Structural and optical characterizations of synthesized ZnO NPs were thoroughly probed applying X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray (EDX) analysis, X-ray photoelectron spectroscopy (XPS), UV- Visible absorption and fluorescence (FL) spectroscopy. The XRD and TEM analyses revealed hexagonal wurtzite phase with 25-30 nm size. EDX analysis indicated oxygen (O) rich composition of nanoparticles. In accordance with EDX, XPS analysis verifies Oi rich stoichiometry of prepared NPs. Furthermore, concurrence of lattice oxygen (OL), interstitial oxygen (Oi) and oxygen vacancy (VO) in ZnO NPs was demonstrated through XPS analysis. Size quantization of nanoparticles is evident by blue shift of UV-Visible absorption energy. The FL spectroscopic investigations ascertain the existence of several discrete and defect states and radiative transitions occurring therein. Display of visible emission from oxygen defect states and most importantly, excess of Oi defects in prepared ZnO nanoparticles, was well established through FL study

  9. Investigation of Hill's optical turbulence model by means of direct numerical simulation.

    Science.gov (United States)

    Muschinski, Andreas; de Bruyn Kops, Stephen M

    2015-12-01

    For almost four decades, Hill's "Model 4" [J. Fluid Mech. 88, 541 (1978) has played a central role in research and technology of optical turbulence. Based on Batchelor's generalized Obukhov-Corrsin theory of scalar turbulence, Hill's model predicts the dimensionless function h(κl(0), Pr) that appears in Tatarskii's well-known equation for the 3D refractive-index spectrum in the case of homogeneous and isotropic turbulence, Φn(κ)=0.033C2(n)κ(-11/3) h(κl(0), Pr). Here we investigate Hill's model by comparing numerical solutions of Hill's differential equation with scalar spectra estimated from direct numerical simulation (DNS) output data. Our DNS solves the Navier-Stokes equation for the 3D velocity field and the transport equation for the scalar field on a numerical grid containing 4096(3) grid points. Two independent DNS runs are analyzed: one with the Prandtl number Pr=0.7 and a second run with Pr=1.0 . We find very good agreement between h(κl(0), Pr) estimated from the DNS output data and h(κl(0), Pr) predicted by the Hill model. We find that the height of the Hill bump is 1.79 Pr(1/3), implying that there is no bump if PrDNS and the Hill model predict that the viscous-diffusive "tail" of h(κl(0), Pr) is exponential, not Gaussian. PMID:26831396

  10. Optical excitation in doped quasi-one-dimensional antiferromagnet (CsMnCl3 centre dot 2H2O+Cu2+)

    International Nuclear Information System (INIS)

    In the wide range of wavelengths and temperatures, the spectra of light absorption and luminescence excitation as well as the emission decay kinetics of a quasi-one-dimensional dielectric crystal CsMnCl3 centre dot 2H2O doped with copper ions (molar concentration 0-3%) are studied. The conclusion is made of the exchange of electronic excitation energy being possible between the matrix and dopant subsystems only in the lowest excited state due to migration of excitation and their trapping by excitation traps of the copper origin. From the analysis of the shape of decay kinetics curves of the matrix luminescence of the crystal, the values of hopping (along the chains of manganese ions) and trapping rates of magnetic excitons are determined

  11. Investigations on the electrical, thermal and optical properties of the nonlinear optical allylthiourea mercury chloride single crystals

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted Highlights: ► The single crystals of dimension 10 × 5 × 5 mm3 of allylthiourea mercury chloride are synthesized using slow evaporation technique. ► The bandgap of allylthiourea mercury chloride crystal is found to be about 3.18 eV. ► The optical nonlinearity of the crystal sample are studied using the open aperture Z-scan technique employing a nanosecond laser at 532 nm, and three photon absorption effect has been found. ► An improved photo pyroelectric is used to find the thermal parameters of the crystal. ► The piezoelectric charge coefficient is determined. -- Abstract: Single crystals of dimension 10 × 5 × 5 mm3 of allylthiourea mercury chloride were synthesized from aqueous solution using slow evaporation technique at ambient temperature. The grown crystals are confirmed by elemental analysis. The band gap of Allylthiourea mercury chloride crystal was found to be about 3.18 eV. The optical nonlinearity of the crystal sample was studied using the open aperture Z-scan technique employing a nanosecond laser at 532 nm, and a three-photon absorption effect has been found. The electrical properties such as dielectric constant, dielectric loss and ac conductivity of the sample were carried out by Agillent E 4980 A LCR meter at different temperatures. An improved photopyroelectric technique was used to find the thermal parameters of the crystal. The piezo electric charge coefficient is also determined.

  12. Optical spectra, energy levels and crystal-field analysis of Sm3 in Na3[Sm(oxydiacetate)3] · 2NaClO4 · 6H2O

    Science.gov (United States)

    May, P. Stanley; Reid, Michael F.; Richardson, F. S.

    Locations and assignments of 144 crystal-field energy levels are reported for Sm3+ in the trigonal Na3[Sm(oxydiacetate)3] · 2NaClO4 · 6H2O system. These energy levels span the 0-36 000 cm-1 energy region, and they were located and assigned from optical emission spectra and from axial and orthoaxial (σ- and π-polarized) absorption measurements on single crystals. The principal SL parentages of the assigned levels span at least 20 Russell-Saunders terms within the 4f5 electronic configuration of Sm3+, and these assigned levels represent nearly half the total number of crystal-field energy levels predicted to occur within the 0-36 000 cm-1 region. The assigned levels are analysed in terms of a 26-parameter electronic hamiltonian in which six of the parameters are defined to represent the 4f-electron/crystal-field interactions for Sm3+ located at sites with trigonal dihedral (D3) symmetry. Of the 26 parameters, 22 (including the six crystal-field parameters) are used in fitting calculated energy levels to the experimental data, and excellent calculated-versus-experimental energy level fits are achieved. Fitted values obtained in this study for the Sm3+ 'free-ion' energy parameters are compared to those reported previously for Sm3+ in LaF3 and LaCl3. Quantitatively determined line strengths are reported for 50 (4f → 4f) crystal-field transitions observed in the single-crystal absorption spectra of Na3[Sm(oxydiacetate)3] · 2NaClO4 · 6H2O at 10 K.

  13. Investigation of optical nanostructures for photovoltaics with near-field scanning microscopy; Untersuchung optischer Nanostrukturen fuer die Photovoltaik mit Nahfeldmikroskopie

    Energy Technology Data Exchange (ETDEWEB)

    Beckers, Thomas

    2011-09-26

    Textured and rough surfaces are known to increase light trapping in solar cells significantly. The development and optimization of these nano-structures is essential to improve the energy conversion efficiency of thin-film solar cells. In the past, first research approaches covered classical and macroscopic investigations, e.g. determining the haze or angularly resolved scattering. These methods do not provide precise explanation for the optical improvement of the devices, because layer thicknesses and structure sizes in thin-film solar cells are smaller than the wavelength of visible light. The impact of local nano-structures and their contribution to the local absorption enhancement is not resolved by macroscopic measurements. In this thesis, near-field scanning optical microscopy is introduced as first near-field investigations of nano-structures for photovoltaics. This provides an insight into local optical effects for relevant surfaces of photovoltaic devices. Investigating the distribution of the electric fields in layer stacks is crucial to understand the absorption in solar cells. Evanescent fields, which occur due to total internal reflection at the interfaces, are measurable by near-field scanning optical microscopy and yield important information about local light trapping. Within the framework of this thesis, correlations between local surface structures and optical near-field effects are shown. In this case structure features of randomly textured surfaces, which optimize local light trapping, are identified. It paves the way to connect microscopic optical effects on the surface with the macroscopic performance of thin-film solar cells. Moreover, the measurement yields a 3D illustration of the electric field distribution over the sample surface. It is an important criterion to prove the results of rigorous diffraction theory. An excellent agreement between experiment and simulation is found. The simulations provide an insight into the material, which is

  14. Preparation and optical characterization of PbCl(2)-Sb(2)O(3)-TeO(2) glasses doped with rare earth elements

    Czech Academy of Sciences Publication Activity Database

    Kostka, Petr; Zavadil, Jiří; Pedlíková, Jitka; Poulain, M.

    2011-01-01

    Roč. 208, č. 8 (2011), s. 1821-1826. ISSN 1862-6300 R&D Projects: GA ČR GA104/08/0734 Institutional research plan: CEZ:AV0Z40320502; CEZ:AV0Z20670512 Keywords : glass * heavy metal oxides * optical properties * photoluminescence Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.463, year: 2011

  15. Contributed Review: A review of the investigation of rare-earth dopant profiles in optical fibers

    Science.gov (United States)

    Sidiroglou, F.; Roberts, A.; Baxter, G.

    2016-04-01

    Rare-earth doped optical fibers have captivated the interest of many researchers around the world across the past three decades. The growth of this research field has been stimulated primarily through their application in optical communications as fiber lasers and amplifiers, although rare-earth doped optical fiber based devices are now finding important uses in many other scientific and industrial areas (for example, medicine, sensing, the military, and material processing). Such wide commercial interest has provided a strong incentive for innovative fiber designs, alternative glass compositions, and novel fabrication processes. A prerequisite for the ongoing progress of this research field is developing the capacity to provide high resolution information about the rare-earth dopant distribution profiles within the optical fibers. This paper constitutes a comprehensive review of the imaging techniques that have been utilized in the analysis of the distribution of the rare-earth ion erbium within the core of optical fibers.

  16. Contributed Review: A review of the investigation of rare-earth dopant profiles in optical fibers.

    Science.gov (United States)

    Sidiroglou, F; Roberts, A; Baxter, G

    2016-04-01

    Rare-earth doped optical fibers have captivated the interest of many researchers around the world across the past three decades. The growth of this research field has been stimulated primarily through their application in optical communications as fiber lasers and amplifiers, although rare-earth doped optical fiber based devices are now finding important uses in many other scientific and industrial areas (for example, medicine, sensing, the military, and material processing). Such wide commercial interest has provided a strong incentive for innovative fiber designs, alternative glass compositions, and novel fabrication processes. A prerequisite for the ongoing progress of this research field is developing the capacity to provide high resolution information about the rare-earth dopant distribution profiles within the optical fibers. This paper constitutes a comprehensive review of the imaging techniques that have been utilized in the analysis of the distribution of the rare-earth ion erbium within the core of optical fibers. PMID:27131646

  17. Optical spectra and crystal field analysis of Dy3+ in Cs2NaDyCl6 and Cs2NaYCl6: Dy3+(5 mol %)

    Science.gov (United States)

    Foster, David R.; Richardson, F. S.

    1985-02-01

    Optical absorption and emission measurements are reported for the Cs2NaDyCl6 and Cs2NaYCl6: Dy3+(5 mol %) systems under variable-temperature (10-298 K) conditions. For both systems, the data are compatible with the retention of octahedral (Oh) site symmetry at the Dy3+ ions over the entire 298 to 10 K temperature range. The only differentiation between the systems is the much greater quantum efficiency of 4F9/2 emission in the doped system vs that in the neat system. Forty-five crystal-field levels spanning 18 multiplets of the Dy3+ 4f9 electronic configuration are located and assigned, and an additional 12 crystal-field levels associated with six other multiplet manifolds are located, but left unassigned. These energy level results are analyzed on the basis of a nine-parameter 4f-electron Hamiltonian operating within a complete Russell-Saunders (SLJ) basis set for the 4f9 configuration of Dy3+. The most intense electric-dipole vibronic lines observed in the optical spectra are assigned to one-phonon vibronic transitions associated with the three odd-parity ``moiety'' modes of the DyCl3-6 octahedral clusters: ν3(t1u), ν4(t1u), and ν6(t2u). Intensity calculations are reported for both the no-phonon magnetic-dipole (origin) transitions and the one-phonon (ν3, ν4, and ν6) electric-dipole vibronic transitions.

  18. On the ClC halogen bond: a rotational study of CF3Cl-CO.

    Science.gov (United States)

    Caminati, Walther; Evangelisti, Luca; Feng, Gang; Giuliano, Barbara M; Gou, Qian; Melandri, Sonia; Grabow, Jens-Uwe

    2016-07-21

    The rotational spectra of two isotopologues (CF3(35)Cl-CO and CF3(37)Cl-CO) of the CF3Cl-CO adduct have been investigated and analyzed using supersonic-jet Fourier transform microwave spectroscopy, and found to have the features of a symmetric top. Rotational, centrifugal distortion, and nuclear quadrupole ((35)Cl and (37)Cl) coupling constants have been precisely obtained from high-resolution measurements. The two subunits of the complex are held together via a ClC halogen bond interaction. Information on the internal dynamics and the dissociation energy of the complex is provided. PMID:27049637

  19. The Optical Absorption Coefficient of Bean Seeds Investigated Using Photoacoustic Spectroscopy

    Science.gov (United States)

    Sanchez-Hernandez, G.; Hernandez-Aguilar, C.; Dominguez-Pacheco, A.; Cruz-Orea, A.; Perez-Reyes, M. C. J.; Martinez, E. Moreno

    2015-06-01

    A knowledge about seed optical parameters is of great relevance in seed technology practice. Such parameters provide information about its absorption and reflectance, which could be useful for biostimulation processes, by light sources, in early stages of seed germination. In the present research photoacoustic spectroscopy (PAS) and the Rosencwaig and Gersho model were used to determine the optical absorption coefficient () of five varieties of bean seeds ( Phaseolus vulgaris L.), of different productive cycles; the seeds were biostimulated by laser treatment to evaluate the effects of biostimulation pre-sowing. It was found that the bean varieties V1, V2, V4, and V5 were optically opaque in the visible spectrum; in the case of the V3 variety, this sample was optically transparent from 680 nm. The varieties of the studied bean seeds showed significant statistical differences in sizes and also in their optical absorption spectra. The biostimulation effects showed that the seed samples with a higher optical penetration length had a positive biostimulation, in the percentage of germination, obtaining an enhancement of 47 % compared to the control sample. The utility of PAS for the optical characterization of seeds has been demonstrated in this study of the laser biostimulation process of this kind of samples.

  20. Investigation of light output uniformity and performance using a UV transmitting glass optic for a multi-UV LED array

    Science.gov (United States)

    Jasenak, Brian; Willsey, Rachel; Willsey, Adam; Forish, James

    2016-03-01

    Ultraviolet light-emitting diode (UV LED) adoption is accelerating; they are being used in new applications such as UV curing, germicidal irradiation, nondestructive testing, and forensic analysis. In many of these applications, it is critically important to produce a uniform light distribution and consistent surface irradiance. Flat panes of fused quartz, silica, or glass are commonly used to cover and protect multi-UV LED arrays. However, they don't offer the advantages of an optical lens design. An investigation was conducted to determine the effect of a secondary glass optic on the uniformity of the light distribution and irradiance. Glass optics capable of transmitting UV-A, UV-B, and UV-C wavelengths can improve light distribution and intensity. In this study, a UV transmitting glass formulation and secondary linear optic were designed and manufactured to demonstrate their effects on achievable irradiance intensity and uniformity. Prismatic patterning on the light source surface of the lens was used to minimize reflection losses on the incident surface of the glass. Fresnel optics were molded into the opposite side of the UV transmitting glass to control the refraction of the light and to gain the desired light intensity distribution from two multi-UV LED arrays. A 20% increase in relative irradiance was observed while maintaining the same coverage area. This work discusses the optical design and the resulting benefits of controlled light output on UV LED systems, which include reduced driving current, decreased thermal deterioration, improved energy efficiency, and longer LED lifetime.

  1. A first-principles investigation of the optical spectra of oxidized graphene

    KAUST Repository

    Singh, Nirpendra

    2013-01-14

    The electronic and optical properties of mono, di, tri, and tetravacancies in graphene are studied in comparison to each other, using density functional theory. In addition, oxidized monovacancies are considered for different oxygen concentrations. Pristine graphene is found to be more absorptive than any defect configuration at low energy. We demonstrate characteristic differences in the optical spectra of the various defects for energies up to 3 eV. This makes it possible to quantify by optical spectroscopy the ratios of the defect species present in a sample.

  2. Investigation into local cell mechanics by atomic force microscopy mapping and optical tweezer vertical indentation.

    Science.gov (United States)

    Coceano, G; Yousafzai, M S; Ma, W; Ndoye, F; Venturelli, L; Hussain, I; Bonin, S; Niemela, J; Scoles, G; Cojoc, D; Ferrari, E

    2016-02-12

    Investigating the mechanical properties of cells could reveal a potential source of label-free markers of cancer progression, based on measurable viscoelastic parameters. The Young's modulus has proved to be the most thoroughly studied so far, however, even for the same cell type, the elastic modulus reported in different studies spans a wide range of values, mainly due to the application of different experimental conditions. This complicates the reliable use of elasticity for the mechanical phenotyping of cells. Here we combine two complementary techniques, atomic force microscopy (AFM) and optical tweezer microscopy (OTM), providing a comprehensive mechanical comparison of three human breast cell lines: normal myoepithelial (HBL-100), luminal breast cancer (MCF-7) and basal breast cancer (MDA-MB-231) cells. The elastic modulus was measured locally by AFM and OTM on single cells, using similar indentation approaches but different measurement parameters. Peak force tapping AFM was employed at nanonewton forces and high loading rates to draw a viscoelastic map of each cell and the results indicated that the region on top of the nucleus provided the most meaningful results. OTM was employed at those locations at piconewton forces and low loading rates, to measure the elastic modulus in a real elastic regime and rule out the contribution of viscous forces typical of AFM. When measured by either AFM or OTM, the cell lines' elasticity trend was similar for the aggressive MDA-MB-231 cells, which were found to be significantly softer than the other two cell types in both measurements. However, when comparing HBL-100 and MCF-7 cells, we found significant differences only when using OTM. PMID:26683826

  3. Investigation into local cell mechanics by atomic force microscopy mapping and optical tweezer vertical indentation

    Science.gov (United States)

    Coceano, G.; Yousafzai, M. S.; Ma, W.; Ndoye, F.; Venturelli, L.; Hussain, I.; Bonin, S.; Niemela, J.; Scoles, G.; Cojoc, D.; Ferrari, E.

    2016-02-01

    Investigating the mechanical properties of cells could reveal a potential source of label-free markers of cancer progression, based on measurable viscoelastic parameters. The Young’s modulus has proved to be the most thoroughly studied so far, however, even for the same cell type, the elastic modulus reported in different studies spans a wide range of values, mainly due to the application of different experimental conditions. This complicates the reliable use of elasticity for the mechanical phenotyping of cells. Here we combine two complementary techniques, atomic force microscopy (AFM) and optical tweezer microscopy (OTM), providing a comprehensive mechanical comparison of three human breast cell lines: normal myoepithelial (HBL-100), luminal breast cancer (MCF-7) and basal breast cancer (MDA-MB-231) cells. The elastic modulus was measured locally by AFM and OTM on single cells, using similar indentation approaches but different measurement parameters. Peak force tapping AFM was employed at nanonewton forces and high loading rates to draw a viscoelastic map of each cell and the results indicated that the region on top of the nucleus provided the most meaningful results. OTM was employed at those locations at piconewton forces and low loading rates, to measure the elastic modulus in a real elastic regime and rule out the contribution of viscous forces typical of AFM. When measured by either AFM or OTM, the cell lines’ elasticity trend was similar for the aggressive MDA-MB-231 cells, which were found to be significantly softer than the other two cell types in both measurements. However, when comparing HBL-100 and MCF-7 cells, we found significant differences only when using OTM.

  4. Diffuse optical intracluster light as a measure of stellar tidal stripping: the cluster CL0024+17 at $z\\sim $0.4 observed at LBT

    CERN Document Server

    Giallongo, E; Grazian, A; Gallozzi, S; Castellano, M; Fiore, F; Fontana, A; Pentericci, L; Boutsia, K; Paris, D; Speziali, R; Testa, V

    2013-01-01

    We have evaluated the diffuse intracluster light (ICL) in the central core of the galaxy cluster CL0024+17 at $z\\sim 0.4$ observed with the prime focus camera (LBC) at LBT. The measure required an accurate removal of the galaxies light within $\\sim 200$ kpc from the center. The residual background intensity has then been integrated in circular apertures to derive the average ICL intensity profile. The latter shows an approximate exponential decline as expected from theoretical cold dark matter models. The radial profile of the ICL over the galaxies intensity ratio (ICL fraction) is increasing with decreasing radius but near the cluster center it starts to bend and then decreases where the overlap of the halos of the brightest cluster galaxies becomes dominant. Theoretical expectations in a simplified CDM scenario show that the ICL fraction profile can be estimated from the stripped over galaxy stellar mass ratio in the cluster. It is possible to show that the latter quantity is almost independent of the prope...

  5. An investigation of the surface energy and optical transmittance of copper oxide thin films prepared by reactive magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Ogwu, A.A. [Thin Film Centre, Electronic Engineering and Physics Division, School of Computing, Paisley University, High Street, Paisley PA1 2BE, Scotland (United Kingdom)]. E-mail: abraham.ogwu@paisley.ac.uk; Bouquerel, E. [Thin Film Centre, Electronic Engineering and Physics Division, School of Computing, Paisley University, High Street, Paisley PA1 2BE, Scotland (United Kingdom); Ademosu, O. [Thin Film Centre, Electronic Engineering and Physics Division, School of Computing, Paisley University, High Street, Paisley PA1 2BE, Scotland (United Kingdom); Moh, S. [Thin Film Centre, Electronic Engineering and Physics Division, School of Computing, Paisley University, High Street, Paisley PA1 2BE, Scotland (United Kingdom); Crossan, E. [Thin Film Centre, Electronic Engineering and Physics Division, School of Computing, Paisley University, High Street, Paisley PA1 2BE, Scotland (United Kingdom); Placido, F. [Thin Film Centre, Electronic Engineering and Physics Division, School of Computing, Paisley University, High Street, Paisley PA1 2BE, Scotland (United Kingdom)

    2005-11-15

    Copper oxide films have been sputter deposited on glass substrates by reactive radio frequency (rf) magnetron sputtering, using a solid copper target and an argon-oxygen gas atmosphere. The films were characterised by scanning electron microscopy/energy dispersive analysis of X-rays, X-ray photoelectron spectroscopy, atomic force microscopy, profilometry, spectrophotometry and surface energy measurements. The effect of input rf power and oxygen flow rate during deposition on the dispersive, polar and acid-base components of the surface energy of the copper oxide films was investigated. The components of the surface energy were determined by the Owens-Wendt and the Van Oss-Chaudhry-Good method. The Lifshitz-van der Waals dispersive interaction force was found to be the major contributor to the surface energy of the films and the origin of their hydrophobicity. Optical transmission in the prepared films was measured by spectrophotometry in the 400-850 nm wavelength region. We observed a maximum transmission of between 40% and 80% for copper oxide films prepared at a low rf power of 200 W, for the oxygen flow rates investigated. The optical bandgap values of the films ranged between 2.4 and 2.05 eV. The dependence of the optical properties of the films like optical transmittance and optical bandgap on deposition parameters like input rf power and physical properties like thickness and roughness was investigated in the wavelength range 400-850 nm. This information is expected to underlie the successful development of durable copper oxide films for technological applications requiring controlled optical transmission in the visible.

  6. An investigation of the surface energy and optical transmittance of copper oxide thin films prepared by reactive magnetron sputtering

    International Nuclear Information System (INIS)

    Copper oxide films have been sputter deposited on glass substrates by reactive radio frequency (rf) magnetron sputtering, using a solid copper target and an argon-oxygen gas atmosphere. The films were characterised by scanning electron microscopy/energy dispersive analysis of X-rays, X-ray photoelectron spectroscopy, atomic force microscopy, profilometry, spectrophotometry and surface energy measurements. The effect of input rf power and oxygen flow rate during deposition on the dispersive, polar and acid-base components of the surface energy of the copper oxide films was investigated. The components of the surface energy were determined by the Owens-Wendt and the Van Oss-Chaudhry-Good method. The Lifshitz-van der Waals dispersive interaction force was found to be the major contributor to the surface energy of the films and the origin of their hydrophobicity. Optical transmission in the prepared films was measured by spectrophotometry in the 400-850 nm wavelength region. We observed a maximum transmission of between 40% and 80% for copper oxide films prepared at a low rf power of 200 W, for the oxygen flow rates investigated. The optical bandgap values of the films ranged between 2.4 and 2.05 eV. The dependence of the optical properties of the films like optical transmittance and optical bandgap on deposition parameters like input rf power and physical properties like thickness and roughness was investigated in the wavelength range 400-850 nm. This information is expected to underlie the successful development of durable copper oxide films for technological applications requiring controlled optical transmission in the visible

  7. Construction of force measuring optical tweezers instrumentation and investigations of biophysical properties of bacterial adhesion organelles

    CERN Document Server

    Andersson, Magnus

    2015-01-01

    Optical tweezers are a technique in which microscopic-sized particles, including living cells and bacteria, can be non-intrusively trapped with high accuracy solely using focused light. The technique has therefore become a powerful tool in the field of biophysics. Optical tweezers thereby provide outstanding manipulation possibilities of cells as well as semi-transparent materials, both non-invasively and non-destructively, in biological systems. In addition, optical tweezers can measure minute forces (< 10-12 N), probe molecular interactions and their energy landscapes, and apply both static and dynamic forces in biological systems in a controlled manner. The assessment of intermolecular forces with force measuring optical tweezers, and thereby the biomechanical structure of biological objects, has therefore considerably facilitated our understanding of interactions and structures of biological systems. Adhesive bacterial organelles, so called pili, mediate adhesion to host cells and are therefore crucial...

  8. Stress-induced birefringence in elastomers doped with ferrofluid magnetic particles: Mechanical and optical investigation

    Energy Technology Data Exchange (ETDEWEB)

    Sena, C. [Instituto de Fisica, Universidade de Sao Paulo, Caixa postal 66318, Sao Paulo, SP 05315-970 (Brazil); Bailey, C. [Liquid Crystal Institute, Kent State University, P.O. Box 5190, Kent, OH 44242-0001 (United States); Godinho, M.H. [Faculdade de Ciencias e Tecnologia e CENIMAT, Universidade Nova de Lisboa, Quinta da Torre, P-2829-516 Caparica (Portugal); Figueirinhas, J.L. [CFMC, Universidade de Lisboa, Avenida Prof. Gama Pinto 2, 1649 003 Lisbon (Portugal); Palffy-Muhoray, P. [Liquid Crystal Institute, Kent State University, P.O. Box 5190, Kent, OH 44242-0001 (United States); Figueiredo Neto, A.M. [Instituto de Fisica, Universidade de Sao Paulo, Caixa postal 66318, Sao Paulo, SP 05315-970 (Brazil)]. E-mail: afigueiredo@if.usp.br

    2006-05-15

    Magnetic nanoparticles from magnetic colloidal suspensions were incorporated in the urethane/urea elastomer (PU/PBDO) by adding to the prepolymers solution in toluene diverse amounts of magnetite grains. It is shown that ferrofluid grains can be efficiently incorporated into the elastomer according to this procedure. Mechanical and optical experiments performed show that the elastomer preparation procedure (casting) introduces a structural anisotropy on the optically isotropic sample. This fact is put in evidence by the measurements of the Young's moduli and orientation of the sample's optical axis under stress. The dependence of the phase shift of both the pure and ferrofluid-doped elastomer samples under strain is linear, and the strain-optic coefficient is show to be linear with the ferrofluid concentration.

  9. Stress-induced birefringence in elastomers doped with ferrofluid magnetic particles: Mechanical and optical investigation

    International Nuclear Information System (INIS)

    Magnetic nanoparticles from magnetic colloidal suspensions were incorporated in the urethane/urea elastomer (PU/PBDO) by adding to the prepolymers solution in toluene diverse amounts of magnetite grains. It is shown that ferrofluid grains can be efficiently incorporated into the elastomer according to this procedure. Mechanical and optical experiments performed show that the elastomer preparation procedure (casting) introduces a structural anisotropy on the optically isotropic sample. This fact is put in evidence by the measurements of the Young's moduli and orientation of the sample's optical axis under stress. The dependence of the phase shift of both the pure and ferrofluid-doped elastomer samples under strain is linear, and the strain-optic coefficient is show to be linear with the ferrofluid concentration

  10. Optical and electrical diagnostics for the investigation of edge turbulence in fusion plasmas

    International Nuclear Information System (INIS)

    A new, two dimensional and fast diagnostic system has been developed for studying the dynamic structure of plasma turbulence; it will be used in the edge of the reversed-field pinch devices TPE-RX and RFX. The system consists of a gas-puffing nozzle, 32 optical channels measuring Hα emitted from the puffed gas (to study the optical emissivity of turbulent patterns and to analyze structures in two dimensions), and an array of Langmuir probes (to compare the turbulent pattern with the optical method and to measure the local plasma parameters). The signals can be acquired at 10 Msamples/s with 2 MHz band width. The design of the system, calibrations, and tests of the electronic circuitry and the optical sensors are presented

  11. Investigation on Characteristics and the Improving Method of Double Loop Optical Buffer

    Institute of Scientific and Technical Information of China (English)

    WANG Yong-Jun; WU Chong-Qing; WANG Zhi; YANG Shuang-Shou; ZHAO Shuang; WANG Ya-Ping; SHU Da; ZHAO Xi

    2009-01-01

    @@ We establish an equivalent cascaded semiconductor optical amplifier system model to analyze the characteristics of the double loop optical buffer (DLOB). The theoretical analysis finds that the performance of the DLOB can be improved by inserted amplifying process in an interval of some cycles. The experiment demonstrates that the buffered cycles can be improved from 20 to 50 and the bit error rate is less than 10-9 by inserting amplifying process in an interval of about 10 cycles.

  12. Electronic structure of phthalocyanines : Theoretical investigation of the optical properties of phthalocyanine monomers, dimers, and crystals

    OpenAIRE

    Ortí Guillén, Enrique; Brédas, J.L.; Clarisse, C.

    1990-01-01

    We present valence effective Hamiltonian (VEH) calculations on the optical absorptions of a series of phthalocyanine compounds: the metal‐free phthalocyanine molecule, a model system for the lithium phthalocyanine molecule, the metal‐free phthalocyanine dimer, and model systems for the lutetium diphthalocyanine and the lithium phthalocyanine crystal. For these compounds, it is found that the major factor influencing the evolution of the optical transitions is not the electronic structure of t...

  13. Theoretical investigation of carrier transfer by an optical contacting scheme for optoelectronic application

    Science.gov (United States)

    Yang, Jianfeng; Ge, Rongchun; Zhang, Zhilong; Chen, Weijian; Wang, Bo; Feng, Yu; Huang, Shujuan; Shrestha, Santosh; Patterson, Robert; Conibeer, Gavin

    2016-04-01

    As a promising charge carrier transfer scheme, optical coupling could potentially improve the performance of an optoelectronic device for energy harvesting based on well developed nanotechnology. By extracting carriers optically, the functional features of the nano-structured material could be better used by minimizing the concerns about its electrical properties. In this paper, we present a rigorous electromagnetic model to analyze the optical carrier transfer problem. The flow of the energy is analyzed carefully by the photon transfer spectrum, and the photon emitters (electron-hole pairs) are assumed in a thermal equilibrium described by Bose-Einstein distribution. The result shows that an energy selective carrier transfer can be optically achieved at the device level by integrating the emitter and receiver into a nano-optical resonator, where both the photon emission and absorption are significantly amplified by a near-field coupling around the resonant frequency. General design and optimization schemes in practice are addressed by examining the influence of the photonic design and an energy dependent emissivity of the emitter, which can be used to develop the optical contacting concept further.

  14. Acoustical and optical investigations of the size effect in nematic-isotropic phase transition in liquid crystal microemulsions

    Science.gov (United States)

    Maksimochkin, G. I.; Pasechnik, S. V.; Lukin, A. V.

    2015-07-01

    The absorption of ultrasound (at a frequency of 2.7 MHz) and the depolarized light transmission and scattering (at a wavelength of 630 nm) in liquid crystal (LC) emulsions have been studied during the nematic-isotropic (N-I) phase transition in LC droplets with radii ranging from 150 to 2300 nm. The obtained acoustical and optical data are used to determine the influence of the droplet size on characteristics of the N-I phase transition. It is shown that the acoustical and optical characteristics of LC emulsions have good prospects to be used for the investigation of phase transitions in submicron samples.

  15. Nonlinear optical method for the investigation of spectral properties of biomolecular complexes: second harmonic generation in ordered structures of bacteriorhodopsin

    Science.gov (United States)

    Aktsipetrov, Oleg A.; Fedyanin, Andrew A.; Murzina, Tatyana V.; Borisevich, G. P.; Kononenko, A. A.

    1995-02-01

    For the first time the method of the second harmonic generation was used to study the photo- and electrically induced nonlinear optical transformations in thin oriented films of purple membranes (PM). Variations of the film nonlinear susceptibility were investigated as the bacteriorhodopsin (bR) molecule underwent the cycle of photoinduced transformations for both dry electrically oriented films and bR molecules embedded into poly(vinyl alcohol) matrix. The electrically induced changes of the nonlinear optical properties were studied for the electrostatic field strength up to the values 4 (DOT) 104 V/cm. Nonlinear susceptibilities of oriented and nonoriented dried PM films are compared.

  16. Numerical Investigation on Performance of In-Building Plastic Optical Fiber Transmission Systems and Role of Digital Television Broadcasting

    Science.gov (United States)

    Matera, Francesco; Tiano, Stefania; Settembre, Marina

    2012-07-01

    This article reports a numerical investigation on the transmission performance of multilevel systems operating in building links encompassing step-index plastic optical fibers. For such an aim, a simplified model for the multimode fiber propagation is introduced. A sub-carrier multiplexing technique is also simulated to demonstrate the distribution of broadcasting television channels by adopting such fibers. The reported results show that a unique building network based on step-index plastic optical fibers is suitable to carry both Ethernet and broadcast TV signals in all rooms.

  17. Comprehensive investigation of optical and electronic properties of tunable InAs QDs optically active at O-band telecommunication window with (In)GaAs surrounding material

    International Nuclear Information System (INIS)

    In this paper, we report on the impact of InAs quantum dots' (QDs) position within InGaAs strain reducing layer on their structural and optical properties. Morphological investigation revealed that the QD' size and density are strongly dependent on the InGaAs underlying layer's thickness. Additionally, comprehensive spectroscopic study by room temperature photoreflectance spectroscopy (PR) and temperature dependent photoluminescence (PL) showed that indium segregation and strain driven alloy phase separation alter both the QDs and their surrounding materials. Embedding or covering the InAs QDs by InGaAs has been found to improve their overall properties including an extended emission wavelength up to 1.3 μm. However a pronounced degradation has been observed when growing them on the top of the strain reducing layer, resulting in a broadened size distribution and atypical temperature dependent emission energy and linewidth. -- Highlights: • InAs quantum dots on different Ga(In)As surrounding material were grown by molecular beam epitaxy. • Optical investigation was used to study the impact of InAs QDs' position within InGaAs strain reducing layer with lower indium concentration. • Atomic force microscope images have been employed for the analyses of the optical results. • Indium segregation and strain driven alloy phase separation have been observed to affect both the QDs and their surrounding material. • QDs' emission wavelengths in the International Telecommunication Union O-band at room temperature have been obtained

  18. Pathways for the OH + Cl2 → HOCl + Cl and HOCl + Cl → HCl + ClO Reactions.

    Science.gov (United States)

    Wang, Hongyan; Qiu, Yudong; Czakó, Gábor; Schaefer, Henry F

    2015-07-16

    High level coupled-cluster theory, with spin-orbit coupling evaluated via the Breit-Pauli operator in the interacting-states approach, is used to investigate the OH radical reaction with Cl2 and the subsequent reaction HOCl + Cl. The entrance complex, transition state, and exit complex for both reactions have been determined using the CCSD(T) method with correlation consistent basis sets up to cc-pV6Z. Also reported are CCSDT computations. The OH + Cl2 reaction is predicted to be endothermic by 2.2 kcal/mol, compared to the best experiments, 2.0 kcal/mol. The above theoretical results include zero-point vibrational energy corrections and spin-orbit contributions. The activation energy (Ea) of the OH + Cl2 reaction predicted here, 2.3 kcal/mol, could be as much as 1 kcal/mol too high, but it falls among the four experimental Ea values, which span the range 1.1-2.5 kcal/mol. The exothermicity of the second reaction HOCl + Cl → HCl + ClO is 8.4 kcal/mol, compared to experiment 8.7 kcal/mol. The activation energy for latter reaction is unknown experimentally, but predicted here to be large, 11.5 kcal/mol. There are currently no experiments relevant to the theoretical entrance and exit complexes predicted here. PMID:25965106

  19. Photostimulated process in CsBrCl:Eu2+: a promising image screen phosphor

    International Nuclear Information System (INIS)

    CsBrCl and CsBrCl:Eu2+ have been grown by 'Double Run Bridgman technique'. Optical investigations have been carried out on the samples. The formation of F(Br-) and F(Cl-) centers have been confirmed by optical absorption bands at 640 and 615 nm, respectively. The photoluminescence (PL) spectra for europium (100 ppm) doped CsBrCl samples give emission of europium at 442 nm. This 442 nm emission is due to the transition from T2g component of 4f65d configuration to the ground state 8S of europium. The emission due to the presence of impurities in the host lattice is detected by PL technique. The OH- impurity in the host lattice due to decomposition of the salt in open air gives out emission at 395 and 365 nm. The O2- emission is observed at 465 and 468 nm. Photostimulated luminescence (PSL) process is studied in the samples by exciting them at F-absorption wavelength after irradiation. No PSL is observed for the undoped CsBrCl samples grown in vacuum. The PSL of vacuum grown CsBrCl:Eu2+ samples for excitations at 640 nm [F(Br-)] and 615 nm [F(Cl-)] is observed at 420 nm. It is deciphered that both F(Cl-) and F(Br-) centers contribute to PSL. The two F-centers noticed in absorption are stimulated separately; the resulting PSL signal confirms the participation of F-centers in photostimulated process. The lifetime of the PSL emission for CsBrCl:Eu2+ is determined to be 0.69 μs. Application of the material as a prospective image screen phosphor is elaborated based on PSL results

  20. Investigation of optical nonlinearity of 8-hydroxyquinolinium 2-chloroacetate and 8-hydroxyquinolinium (Z)-3-carboxyacrylate salts by Z-scan technique

    Science.gov (United States)

    Zidan, M. D.; Arfan, A.; Allahham, A.; Naima, D.

    2016-01-01

    A novel two organic salts: 8-hydroxyquinolinium 2-chloroacetate and 8-hydroxyquinolinium (Z)-3-carboxyacrylate were synthesized and characterized using UV-visible, FTIR and NMR measurements. The characterization spectra confirm the expected molecular structure of the prepared salts. The Z-scan technique is used to achieve optical nonlinearity measurements with a CW Diode laser at 635 nm wavelength and 14.5 mW power. The nonlinear optical absorption coefficient (β) and nonlinear refraction (n2) of the two studied compounds were affected by Cl group more than OH. The reverse saturable absorption (RSA) mechanism was responsible for the optical limiting effect. The results suggest that this material considers as a promising candidate for future optical devices applications.

  1. Further studies on electronic guest/host interactions of FeCl3-graphite from Moessbauer spectroscopy - a comparative investigation with FeOCl

    International Nuclear Information System (INIS)

    Moessbauer spectra of first stage FeCl3-graphite and of the inverse Fe(C5H5)2-iron oxide chloride intercalation compounds have been measured between room temperature and 4 K. The spectra at 295 K consist of resonance lines which are characteristic of ferric ions only. In addition the spectra showed high-spin Fe2+ sites at low temperatures. This result may be accounted for by an incomplete redox reaction caused by partial transfer of the π-electrons of the graphite (host layer), or of the ferricinium ions (guest layers), to the adjacent layers. Contrary to what is found in the literature, at low temperatures only these delocated electrons are fixed in the d-orbitals of some Fe3+ atoms resulting in Fe2+ sites. This result suggests that a shielding effect of the chlorine layers exists in these intercalation compounds which hinders a complete electron transfer to the Fe3+ centers at room temperature. (Auth.)

  2. Investigation of etching and deposition processes of Cl2/O2/Ar inductively coupled plasmas on silicon by means of plasma-surface simulations and experiments

    International Nuclear Information System (INIS)

    In this paper, a simulation method is described to predict the etching behaviour of Cl2/O2/Ar inductively coupled plasmas on a Si substrate, as used in shallow trench isolation for the production of electronic devices. The hybrid plasma equipment model (HPEM) developed by Kushner et al is applied to calculate the plasma characteristics in the reactor chamber and two additional Monte Carlo simulations are performed to predict the fluxes, angles and energy of the plasma species bombarding the Si substrate, as well as the resulting surface processes such as etching and deposition. The simulations are performed for a wide variety of operating conditions such as gas composition, chamber pressure, power deposition and substrate bias. It is predicted by the simulations that when the fraction of oxygen in the gas mixture is too high, the oxidation of the Si substrate is superior to the etching of Si by chlorine species, resulting in an etch rate close to zero as is also observed in the experiments.

  3. Synchrotron X-ray investigation of α-Chlorohemin, C34H32ClFeN4O4, an Fe-porphyrin

    Science.gov (United States)

    Kaduk, J. A.; Wong-Ng, W.; Cook, L. P.; Chakraborty, B.; Lapidus, S. H.; Ribaud, L.; Brewer, G.

    2016-03-01

    X-ray data of a powder sample of α-chlorohemin (a member of the porphyrin family), C34H32ClFeN4O4, was collected using synchrotron radiation at the Advanced Photon Source (APS, Argonne National Laboratory). Rietveld Refinement and Density Functional Theory (DFT) calculations were performed for obtaining the structure including positions of hydrogen atoms. The structure was found to be P 1 bar , Z = 2; at 100K the lattice parameters are a = 11.22468(6) Å, b = 13.93930(8) Å, c = 10.79818(9) Å, α = 99.6672(6)°, β = 108.4124(8)°, γ = 106.7175(6)°, and V = 1471.713(19) Å3, and at 295K, a = 11.43217(7) Å, b = 14.06412(10) Å, c = 10.85390(9) Å, α = 98.6655(7)°, β = 108.6294(8)°, γ = 107.5025(7)°, and V = 1517.21(2) Å3, Dx = 1.427 g/cm3. Experimental reference X-ray patterns have also been determined, which will be included in the Powder Diffraction File (PDF).

  4. Investigating the impact of NaCl salinity on growth, β-carotene, and chlorophyll a in the content life of halophytes of algae Chlorella sp.

    OpenAIRE

    Mojtaba Fathi; Alireza Asem

    2013-01-01

    Algae are used for many purposes as: food industry, animal feeding, soil enrichment andbiodiesel production. Chlorella is widely cultivated from microalgae species as it is rich in nutrients andhas its implementation as a healthy food use. In this study, the impact of NaCl salinity on growth, betacarotene,and chlorophyll a of Chlorella sp. has been investigated. This study results in three salinities(10, 30, 50 g L-1, respectively) have shown that 30 g L-1 concentration has the highest value ...

  5. An Optical Section-Assisted In Vivo Rabbit Model for Capsular Bend and Posterior Capsule Opacification Investigation

    Science.gov (United States)

    Zheng, Qian; Yu, Fang; Yu, Xiaoyu; Zhao, Yinying; Ding, Xixia; Zhu, Weigen; Li, Jin; Zhao, Yun-e

    2016-01-01

    Purpose To establish an optical section-assisted in vivo rabbit model for capsular bend and posterior capsule opacification (PCO) investigation. Methods A total of 10 rabbits underwent phacoemulsification surgery and intraocular lens (IOL) implantation. On the basis of the relationship between the anterior capsule and IOL, the rabbits were divided into complete overlap and incomplete overlap groups, in which six and four rabbits were included, respectively. The capsular bend optical sections were assessed using ultra-long scan depth optical coherence tomography (UL-OCT), and posterior capsule opacification was evaluated with slit lamp on postoperative day 3, 7, 14, and 28. In addition, histopathological section was used to verify the accuracy of capsular bend type captured by OCT in three rabbits. Results Based on the special animal model, six capsular bend types were observed, namely, anterior (A), middle (M), posterior (P), detachment (D), funnel (Fun) and furcate adhesion (Fur). On day 3, capsular bend began to form. On 14 days, the capsular bends were comprised of A, M and D types, which were almost maintained until day 28. Histopathological section findings were consistent with optical sectioning results. In the incomplete and complete groups, the earliest PCO within the optical zone were on day 7 and 28, respectively. The incomplete group exhibited higher incidence and faster PCO on day 7 (p = 0.038) and 14 (p = 0.002). Conclusions This animal model not only mimics capsular bend evolution and PCO processes but also produces OCT optical section images equivalent to and more repeatable than histopathology, thereby providing a promising method for the further investigations of PCO. PMID:26840405

  6. Investigating the impact of optical selection effects on observed rest frame prompt GRB properties

    CERN Document Server

    Turpin, Damien; Dezalay, Jean-Pascal; Atteia, Jean-Luc; Klotz, Alain; Dornic, Damien

    2016-01-01

    Measuring gamma-ray burst (GRB) properties in their rest-frame is crucial to understand the physics at work in gamma-ray bursts. This can only be done for GRBs with known redshift. Since redshifts are usually measured from the optical spectrum of the afterglow, correlations between prompt and afterglow emissions may introduce biases in the distribution of rest-frame properties of the prompt emission. Our analysis is based on a sample of 90 GRBs with good optical follow-up and well measured prompt emission. 76 of them have a measure of redshift and 14 have no redshift. We estimate their optical brightness with their R magnitude measured two hours after the trigger and compare the rest frame prompt properties of different classes of GRB afterglow brightness. We find that the optical brightness of GRBs in our sample is mainly driven by their intrinsic afterglow luminosity. We show that GRBs with low and high afterglow optical fluxes have similar Epi , Eiso , Liso , indicating that the rest-frame distributions co...

  7. Investigation of Al doping concentration effect on the structural and optical properties of the nanostructured CdO thin film

    Science.gov (United States)

    Gencer Imer, Arife

    2016-04-01

    Nanostructured aluminium (Al) doped cadmium oxide (CdO) films with highly electrical conductivity and optical transparency have been deposited for the first time on soda-lime glass substrates preheated at 250 °C by ultrasonic spray coating technique. The aluminium dopant content in the CdO film was changed from 0 to 5 at%. The influencing of Al doping on the structural, morphological, electrical and optical properties of the CdO nanostructured films has been investigated. Atomic force microscopy study showed the grain size of the films is an order of nanometers, and it decreases with increase in Al dopant content. All the films having cubic structure with a lattice parameter 4.69 Å were determined via X ray diffraction analysis. The optical band gap value of the films, obtained by optical absorption, was found to increase with Al doping. Electrical studies exhibited mobility, carrier concentration and resistivity of the film strongly dependent on the doping content. It has been evaluated that optical band gap, and grain size of the nanostructured CdO film could be modified by Al doping.

  8. Advancements in Optical Properties of Thermochromic VO 2 Films through Experimental and Numerical Investigations

    Science.gov (United States)

    Miller, Mark J.

    The Department of Energy reports that buildings consume more than 40% of primary energy in the U.S. and that this trend will continue for the foreseeable future. Furthermore, windows constitute a major path for energy losses from buildings and therefore also present a significant opportunity for efficiency improvement and waste reduction. With this in mind, the work in this dissertation is focused on improving the control of solar and thermal radiation through windows. These radiation spectra can be controlled independently because they peak at different wavelengths due to the much higher temperature (5500 °C) of the Sun compared to objects on Earth (25 °C). In this work, a thermochromic material is utilized to control solar irradiance and a low-emissive (low-E) material is used to control thermal radiation. Thermochromic materials possess optical properties that change in response to temperature and low-E coatings are reflective in the mid-infrared (thermal) region. VO 2 is an exciting candidate for thermochromic coatings because its transmittance in the visible region is relatively constant, but its reflectance in the IR increases significantly with temperature. The main technical issues limiting VO2 are luminous transmittance (Tlum) that is too low and a transition temperature (tauc) that is too high. For the low-E coating, (SnO2)x(In 2O3)1-x (ITO glass) was chosen because it has both high luminous transmittance and low emissivity. In this dissertation it is shown that tauc of VO2 can be lowered from 50 to 45 °C by reducing the grain size of the film from 70 to 31 nm. In the area of luminous transmittance, TiO2 is investigated as an anti-reflective coating which can be used to increase Tlum. Later in this work, it is demonstrated that the energy efficiency gained through VO2 can be further improved by combining it with a low-E coating. The multilayer design combines anti-reflection in the visible region, thermochromism the near-IR and low emissivity in the

  9. Investigations of Optical Coherence Properties in an Erbium-doped Silicate Fiber for Quantum State Storage

    CERN Document Server

    Staudt, M U; Afzelius, M; Jaccard, D; Tittel, W; Gisin, Nicolas; Staudt, Matthias U.; Hastings-Simon, Sara R.; Afzelius, Mikael; Jaccard, Didier; Tittel, Wolfgang; Gisin, Nicolas

    2006-01-01

    We studied optical coherence properties of the 1.53 $\\mu$m telecommunication transition in an Er$^{3+}$-doped silicate optical fiber through spectral holeburning and photon echoes. We find decoherence times of up to 3.8 $\\mu$s at a magnetic field of 2.2 Tesla and a temperature of 150 mK. A strong magnetic-field dependent optical dephasing was observed and is believed to arise from an interaction between the electronic Er$^{3+}$ spin and the magnetic moment of tunneling modes in the glass. Furthermore, we observed fine-structure in the Erbium holeburning spectrum originating from superhyperfine interaction with $^{27}$Al host nuclei. Our results show that Er$^{3+}$-doped silicate fibers are promising material candidates for quantum state storage.

  10. Investigation study on the nonlinear optical properties of natural dyes: Chlorophyll a and b

    Science.gov (United States)

    Kouissa, B.; Bouchouit, K.; Abed, S.; Essaidi, Z.; Derkowska, B.; Sahraoui, B.

    2013-04-01

    We report the results on third and second order nonlinear optical susceptibilities of two natural pigments extracted from spinach. The last were identified by UV-vis spectral analysis. Thin films were prepared by spin coating technique and deposited on glass substrate. The measurements of third order nonlinear optical susceptibilities were performed in solutions using degenerate four wave mixing technique (DFWM) at the measurement wavelength of 532 nm. The third and second order nonlinear optical susceptibilities of the studied pigments were also evaluated on thin films using the third and second harmonics generation (THG and SHG) Maker fringes technique respectively at 1064 nm. All these results were in good agreement with the literature data.

  11. Investigation on the electrochemical behavior of neodymium chloride at W, Al and Cd electrodes in molten LiCl-KCl eutectic

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Electrochemical behavior of neodymium (III) ion was studied in LiCl-KCl eutectic melt in the temperature range 723-798 K on inert tungsten electrode using various transient electrochemical techniques such as cyclic voltammetry, convolution voltammetry, chronopotentiometry and square wave voltammetry. The reduction of Nd(III) ion to Nd metal on tungsten electrode takes place in two steps- Nd(III)/Nd(II) and Nd(II)/Nd(0). Reduction of Nd(III) to Nd(II) showed reversible electrode behavior and that for Nd(II) to Nd metal followed the quasi-reversible behavior. Heterogeneous rate constant for the reduction, Nd(II)/Nd(0) was estimated from the convoluted voltammograms. The apparent standard electrode potentials,ENd(III)/Nd(II)*, ENd(II)/Nd(0)* and ENd(III)/Nd(0)* were estimated from the cyclic voltammograms and open circuit potentiograms. • The electrode behavior of Nd(III) ion on solid aluminium electrode and liquid cadmium electrode was studied by cyclic voltammetry. Under-potential reduction of Nd(III) ion takes place on Al and Cd cathodes in a single step with three electron transfer. The apparent standard electrode potentials, ENd(III)/Nd(Al)* and ENd(III)/Nd(Cd)* were estimated for different temperatures in the range 698-773 K. The formation of intermetallics, Al11Nd3 and Cd11Nd were studied from open circuit potential measurement on Al and Cd film electrode respectively. Thermodynamic properties of Nd-Al and Nd-Cd systems were evaluated. - Abstract: Electrochemical behavior of neodymium (III) ion was studied in LiCl-KCl eutectic melt in the temperature range 723-798 K on inert tungsten electrode using various transient electrochemical techniques such as cyclic voltammetry, convolution voltammetry, chronopotentiometry and square wave voltammetry. The reduction of Nd(III) ion to Nd metal on tungsten electrode takes place in two steps- Nd(III)/Nd(II) and Nd(II)/Nd(0). The diffusion coefficient of Nd(III) and Nd (II) ions were

  12. Investigating the Optical Counterpart Candidates of Four INTEGRAL Sources Localized with Chandra

    Science.gov (United States)

    Özbey Arabacı, Mehtap; Kalemci, Emrah; Tomsick, John A.; Halpern, Jules; Bodaghee, Arash; Chaty, Sylvain; Rodriguez, Jerome; Rahoui, Farid

    2012-12-01

    We report on the optical spectroscopic follow-up observations of the candidate counterparts to four INTEGRAL sources: IGR J04069+5042, IGR J06552-1146, IGR J21188+4901, and IGR J22014+6034. The candidate counterparts were determined with Chandra, and the optical observations were performed with 1.5 m RTT-150 telescope (TÜBİTAK National Observatory, Antalya, Turkey) and 2.4 m Hiltner Telescope (MDM Observatory, Kitt Peak, Arizona). Our spectroscopic results show that one of the two candidates of IGR J04069+5042 and the one observed for IGR J06552-1146 could be active late-type stars in RS CVn systems. However, according to the likelihood analysis based on Chandra and INTEGRAL, two optically weaker sources in the INTEGRAL error circle of IGR J06552-1146 have higher probabilities to be the actual counterpart. The candidate counterparts of IGR J21188+4901 are classified as an active M-type star and a late-type star. Among the optical spectra of four candidates of IGR J22014+6034, two show Hα emission lines, one is a late-type star, and the other is an M type. The likelihood analysis favors a candidate with no distinguishing features in the optical spectrum. Two of the candidates classified as M-type dwarfs, are similar to some IGR candidates claimed to be symbiotic stars. However, some of the prominent features of symbiotic systems are missing in our spectra, and their NIR colors are not consistent with those expected for giants. We consider the IR colors of all IGR candidates claimed to be symbiotic systems and find that low-resolution optical spectrum may not be enough for conclusive identification.

  13. INVESTIGATING THE OPTICAL COUNTERPART CANDIDATES OF FOUR INTEGRAL SOURCES LOCALIZED WITH CHANDRA

    Energy Technology Data Exchange (ETDEWEB)

    Oezbey Arabac Latin-Small-Letter-Dotless-I , Mehtap [Department of Physics, Middle East Technical University, Ankara, 06531 (Turkey); Kalemci, Emrah [Faculty of Engineering and Natural Sciences, Sabanc Latin-Small-Letter-Dotless-I University, Orhanl Latin-Small-Letter-Dotless-I -Tuzla, Istanbul, 34596 (Turkey); Tomsick, John A.; Bodaghee, Arash [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Halpern, Jules [Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027-6601 (United States); Chaty, Sylvain; Rodriguez, Jerome [AIM (UMR-E 9005 CEA/DSM-CNRS-Universite Paris Diderot) Irfu/Service d' Astrophysique, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Rahoui, Farid, E-mail: mehtap@astroa.physics.metu.edu.tr [Astronomy Department, Harvard University, 60 Garden Street, Cambridge, MA 02138 (United States)

    2012-12-10

    We report on the optical spectroscopic follow-up observations of the candidate counterparts to four INTEGRAL sources: IGR J04069+5042, IGR J06552-1146, IGR J21188+4901, and IGR J22014+6034. The candidate counterparts were determined with Chandra, and the optical observations were performed with 1.5 m RTT-150 telescope (TUeBITAK National Observatory, Antalya, Turkey) and 2.4 m Hiltner Telescope (MDM Observatory, Kitt Peak, Arizona). Our spectroscopic results show that one of the two candidates of IGR J04069+5042 and the one observed for IGR J06552-1146 could be active late-type stars in RS CVn systems. However, according to the likelihood analysis based on Chandra and INTEGRAL, two optically weaker sources in the INTEGRAL error circle of IGR J06552-1146 have higher probabilities to be the actual counterpart. The candidate counterparts of IGR J21188+4901 are classified as an active M-type star and a late-type star. Among the optical spectra of four candidates of IGR J22014+6034, two show H{alpha} emission lines, one is a late-type star, and the other is an M type. The likelihood analysis favors a candidate with no distinguishing features in the optical spectrum. Two of the candidates classified as M-type dwarfs, are similar to some IGR candidates claimed to be symbiotic stars. However, some of the prominent features of symbiotic systems are missing in our spectra, and their NIR colors are not consistent with those expected for giants. We consider the IR colors of all IGR candidates claimed to be symbiotic systems and find that low-resolution optical spectrum may not be enough for conclusive identification.

  14. Investigating Tissue Optical Properties and Texture Descriptors of the Retina in Patients with Multiple Sclerosis.

    Directory of Open Access Journals (Sweden)

    Boglárka Enikő Varga

    Full Text Available To assess the differences in texture descriptors and optical properties of retinal tissue layers in patients with multiple sclerosis (MS and to evaluate their usefulness in the detection of neurodegenerative changes using optical coherence tomography (OCT image segmentation.38 patients with MS were examined using Stratus OCT. The raw macular OCT data were exported and processed using OCTRIMA software. The enrolled eyes were divided into two groups, based on the presence of optic neuritis (ON in the history (MSON+ group, n = 36 and MSON- group, n = 31. Data of 29 eyes of 24 healthy subjects (H were used as controls. A total of seven intraretinal layers were segmented and thickness as well as optical parameters such as contrast, fractal dimension, layer index and total reflectance were measured. Mixed-model ANOVA analysis was used for statistical comparisons.Significant thinning of the retinal nerve fiber layer (RNFL, ganglion cell/inner plexiform layer complex (GCL+IPL and ganglion cell complex (GCC, RNFL+GCL+IPL was observed between study groups in all comparisons. Significant difference was found in contrast in the RNFL, GCL+IPL, GCC, inner nuclear layer (INL and outer plexiform layer when comparing MSON+ to the other groups. Higher fractal dimension values were observed in GCL+IPL and INL layers when comparing H vs. MSON+ groups. A significant difference was found in layer index in the RNFL, GCL+IPL and GCC layers in all comparisons. A significant difference was observed in total reflectance in the RNFL, GCL+IPL and GCC layers between the three examination groups.Texture and optical properties of the retinal tissue undergo pronounced changes in MS even without optic neuritis. Our results may help to further improve the diagnostic efficacy of OCT in MS and neurodegeneration.

  15. INVESTIGATING THE OPTICAL COUNTERPART CANDIDATES OF FOUR INTEGRAL SOURCES LOCALIZED WITH CHANDRA

    International Nuclear Information System (INIS)

    We report on the optical spectroscopic follow-up observations of the candidate counterparts to four INTEGRAL sources: IGR J04069+5042, IGR J06552–1146, IGR J21188+4901, and IGR J22014+6034. The candidate counterparts were determined with Chandra, and the optical observations were performed with 1.5 m RTT-150 telescope (TÜBİTAK National Observatory, Antalya, Turkey) and 2.4 m Hiltner Telescope (MDM Observatory, Kitt Peak, Arizona). Our spectroscopic results show that one of the two candidates of IGR J04069+5042 and the one observed for IGR J06552–1146 could be active late-type stars in RS CVn systems. However, according to the likelihood analysis based on Chandra and INTEGRAL, two optically weaker sources in the INTEGRAL error circle of IGR J06552–1146 have higher probabilities to be the actual counterpart. The candidate counterparts of IGR J21188+4901 are classified as an active M-type star and a late-type star. Among the optical spectra of four candidates of IGR J22014+6034, two show Hα emission lines, one is a late-type star, and the other is an M type. The likelihood analysis favors a candidate with no distinguishing features in the optical spectrum. Two of the candidates classified as M-type dwarfs, are similar to some IGR candidates claimed to be symbiotic stars. However, some of the prominent features of symbiotic systems are missing in our spectra, and their NIR colors are not consistent with those expected for giants. We consider the IR colors of all IGR candidates claimed to be symbiotic systems and find that low-resolution optical spectrum may not be enough for conclusive identification.

  16. Investigation of microwave transitions and nonlinear magneto-optical rotation in anti-relaxation-coated cells

    CERN Document Server

    Budker, D; Kimball, D F; Kitching, J; Pustelny, S; Yashchuk, V V

    2004-01-01

    Using laser optical pumping, widths and frequency shifts are determined for microwave transitions between ground-state hyperfine components of $^{85}$Rb and $^{87}$Rb atoms contained in vapor cells with alkane anti-relaxation coatings. The results are compared with data on Zeeman relaxation obtained in nonlinear magneto-optical rotation (NMOR) experiments, a comparison important for quantitative understanding of spin-relaxation mechanisms in coated cells. By comparing cells manufactured over a forty-year period we demonstrate the long-term stability of coated cells, an important property for atomic clocks and magnetometers.

  17. Optical investigation of magneto-structural phase transition in FeRh

    OpenAIRE

    Saidl, V.; Brajer, M.; Horak, L.; Reichlova, H.; Vyborny, K.; Veis, M.; Janda, T.; Trojanek, F.; Fina, I.; Marti, X.; Jungwirth, T.; Nemec, P.

    2015-01-01

    Magneto-structural phase transition in FeRh epitaxial layers was studied optically. It is shown that the transition between the low-temperature antiferromagnetic phase and the high-temperature ferromagnetic phase is accompanied by a rather large change of the optical response in the visible and near infrared spectral ranges. This phenomenon was used to measure the phase transition temperature in FeRh films with thicknesses from 6 to 100 nm and it was observed that the hysteretic transition re...

  18. Optical investigation of the charge-density-wave phase transitions in $NbSe_{3}$

    OpenAIRE

    Perucchi, A.; Degiorgi, L.; Thorne, R.E.

    2003-01-01

    We have measured the optical reflectivity $R(\\omega)$ of the quasi one-dimensional conductor $NbSe_{3}$ from the far infrared up to the ultraviolet between 10 and 300 $K$ using light polarized along and normal to the chain axis. We find a depletion of the optical conductivity with decreasing temperature for both polarizations in the mid to far-infrared region. This leads to a redistribution of spectral weight from low to high energies due to partial gapping of the Fermi surface below the char...

  19. Experimental and theoretical investigations of absolute optical oscillator strengths for valence excitations of nitric oxide

    Institute of Scientific and Technical Information of China (English)

    朱林繁; 钟志萍; 苑震生; 张卫华; 刘小井; 江锡满; 徐克尊; 李家明

    2002-01-01

    The absolute optical oscillator strength density spectra of nitric oxide in the energy region of 5.0-22.0 eV havebeen measured by a high-resolution fast-electron energy loss spectrometer. With the calculated results obtained by themultiscattering self-consistent-field method and channel characteristics, the strongly overlapped spectra in the energyregion of 7.5-9.3 eV have been analysed and the corresponding partially vibrationally resolved optical oscillator strengthshave been estimated from the experimental spectra.

  20. Effects of NaCl and NH4Cl on the initial atmospheric corrosion of zinc

    International Nuclear Information System (INIS)

    Effects of NaCl and NH4Cl on the initial atmospheric corrosion of zinc were investigated via quartz crystal microbalance (QCM) in laboratory at 80% RH and 25 deg C. The results show that both NaCl and NH4Cl can accelerate the initial atmospheric corrosion of zinc. The combined effect of NaCl and NH4Cl on the corrosion of zinc is greater than that caused by NH4Cl and less than that caused by NaCl. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy and electron dispersion X-ray analysis (SEM/EDAX) were used to characterize the corrosion products of zinc. (NH4)2ZnCl4, Zn5(OH)8Cl2 . H2O and ZnO present on zinc surface in the presence of NH4Cl while Zn5(OH)8Cl2 . H2O and ZnO are the dominant corrosion products on NaCl-treated zinc surface. Probable mechanisms are presented to explain the experimental results

  1. Optical absorption spectra, crystal-field analysis, and electric dipole intensity parameters for europium in Na 3[En(ODA) 3]-2NaClO 4·6H 2O

    Science.gov (United States)

    Berry, Mary T.; Schwieters, Charles; Richardson, F. S.

    1988-05-01

    Locations and assignments of 61 crystal-field levels are reported for Eu 3+ in the trigonal Na 3[Eu(oxydiacetate) 3]· 2NaClO 46H 2O system. These energy levels span the 0-37400 cm - energy region, and they were located and assigned from optical emission spectra and from axial and orthoaxial (σ and π-polarized) absorption measurements on single crystals. The assigned crystal-field levels span 22 different multiplet manifolds, with principal parentages derived from seven different f 6 Russell-Saunders terms ( 2F, 5D, 5L, 5H, 5F, 5I, and 5K). The assigned levels are analyzed in terms of a 26-parameter electronic Hamiltonian in which six of the parameters are defined to represent the 4f-electron/crystal-field interactions for Eu 3+ ions located at sites with trigonal dihedral (D 3) symmetry. Quantitative line intensities are reported for 39 individual 4f→4f (crystal-field) transitions observed in the low-temperature (10 K) absorption spectra, and these intensity data are analyzed in terms of a general parametric model for 4f→4f transition intensities in lanthanide systems. The energy and intensity parameterizations provide a basis for calculating the 4f→4f absorption spectra of Eu 3+ in Na 3[Eu(oxydiacetate) 3]· 2NaClO 4·6H 2O over a wide spectral range and excellent agreement between calculated and experimentally measured spectra is obtained. Several of the intensity parameters determined to be important in this study carry information of particular significance to understanding the structural and mechanisticbases of lanthanid

  2. Investigating the Optical Counterpart Candidates of Four INTEGRAL Sources localized with Chandra

    CERN Document Server

    Arabacı, Mehtap Özbey; Tomsick, John A; Halpern, Jules; Bodaghee, Arash; Chaty, Sylvain; Rodriguez, Jerome; Rahoui, Farid

    2012-01-01

    We report on the optical spectroscopic follow up observations of the candidate counterparts to four INTEGRAL sources: IGR J04069+5042, IGR J06552-1146, IGR J21188+4901 and IGR J22014+6034. The candidate counterparts were determined with Chandra, and the optical observations were performed with 1.5-m RTT-150 telescope (T\\"{U}B\\.{I}TAK National Observatory, Antalya, Turkey) and 2.4-m Hiltner Telescope (MDM Observatory, Kitt Peak, Arizona). Our spectroscopic results show that one of the two candidates of IGR J04069+5042 and the one observed for IGR J06552-1146 could be active late-type stars in RS CVn systems. However, according to the likelihood analysis based on Chandra and INTEGRAL, two optically weaker sources in the INTEGRAL error circle of IGR J06552-1146 have higher probabilities to be the actual counterpart. The candidate counterparts of IGR J21188+4901 are classified as an active M-type star and a late-type star. Among the optical spectra of four candidates of IGR J22014+6034, two show H\\alpha emission ...

  3. Investigation on possibility of neutron electric optical devices based on piezoelectric single crystals

    Czech Academy of Sciences Publication Activity Database

    Kaneko, JH.; Otake, Y.; Fujimoto, H.; Kawamura, S.; Watanabe, M.; Fujita, F.; Sawamura, T.; Mikula, Pavol; Furusaka, M.

    2004-01-01

    Roč. 529, č. 1 (2004), s. 166-168. ISSN 0168-9002 Institutional research plan: CEZ:AV0Z1048901 Keywords : cold neutrons * optical device * piezoelectric single crystal Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.349, year: 2004

  4. Investigation of optical transitions of highly charged ions in high density laser produced plasma at PALS

    Czech Academy of Sciences Publication Activity Database

    Rosmej, F.B.; Delserieys, A.; Godbert-Mouret, L.; Schott, R.; Dalimier, E.; Riley, D.; Renner, Oldřich; Krouský, Eduard

    Roma : ENEA, 2006, s. 627. [EPS Conference on Plasma Physics /33./. Roma (IT), 19.06.2006-23.06.2006] R&D Projects: GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z10100523 Keywords : optical transition * atomic structure * Stark and Zeeman effects Subject RIV: BL - Plasma and Gas Discharge Physics

  5. Investigating the use of the acousto-optic effect for acoustic holography

    DEFF Research Database (Denmark)

    Torras Rosell, Antoni; Fernandez Grande, Efren; Jacobsen, Finn;

    2012-01-01

    . Two different holographic methods are examined for this purpose. One method first reconstructs the hologram plane using acousto-optic tomography and then propagates it using conventional near-field acoustic holography (NAH). The other method exploits the so-called Fourier Slice Theorem and bases all...

  6. Optical and UV investigation of the IRAS Seyfert galaxy 1319-164

    Energy Technology Data Exchange (ETDEWEB)

    De Robertis, M.M.; Hutchings, J.B.; Pitts, R.E.

    1988-05-01

    Optical and UV spectroscopy and optical-imaging observations of the bright IR-selected Seyfert galaxy 1319-164 are presented. It is found that the nucleus is reddened by E(B-v) = 0.3 mag, both in the lines and continuum. The galaxy is large and contains little, if any, spiral structure. There are low-brightness structures at about 5 arcsec from the nucleus, and we find the emission-line region is offset from the continuum by 0.17 arcsec or roughly 50 pc. The UV and optical emission-line profiles show substantial blueward asymmetries, and linewidths are consistent with a type 2 Seyfert galaxy. C IV 1550 A, however, appears to have a broad component which is offset some 600 km/s to the red with respect to the narrowline component. The UV-optical line ratios are similar to other high-ionization Seyfert 2 galaxies, except that the reddening-correlated Ly-alpha/H-beta ratio is less than case B. Nitrogen appears unusually strong in the emission-line spectrum as well. The peculiarities of the system and whether it represents a large new subgroup of AGN are discussed. 26 references.

  7. Optical and UV investigation of the IRAS Seyfert galaxy 1319-164

    International Nuclear Information System (INIS)

    Optical and UV spectroscopy and optical-imaging observations of the bright IR-selected Seyfert galaxy 1319-164 are presented. It is found that the nucleus is reddened by E(B-v) = 0.3 mag, both in the lines and continuum. The galaxy is large and contains little, if any, spiral structure. There are low-brightness structures at about 5 arcsec from the nucleus, and we find the emission-line region is offset from the continuum by 0.17 arcsec or roughly 50 pc. The UV and optical emission-line profiles show substantial blueward asymmetries, and linewidths are consistent with a type 2 Seyfert galaxy. C IV 1550 A, however, appears to have a broad component which is offset some 600 km/s to the red with respect to the narrowline component. The UV-optical line ratios are similar to other high-ionization Seyfert 2 galaxies, except that the reddening-correlated Ly-alpha/H-beta ratio is less than case B. Nitrogen appears unusually strong in the emission-line spectrum as well. The peculiarities of the system and whether it represents a large new subgroup of AGN are discussed. 26 references

  8. Investigation of optical currents in coherent and partially coherent vector fields

    DEFF Research Database (Denmark)

    Angelsky, O. V.; Gorsky, M. P.; Maksimyak, P. P.;

    2011-01-01

    arrangements of two-wave and four-wave superposition on the characteris-tics of the microparticle’s motion has been analyzed. The prospects of stud-ying temporal coherence using the proposed approach are made. For the first time, the possibility of diagnostics of optical currents in liquids caused by...

  9. Complex approach to the investigation of short fiber-optic comunication lines

    Science.gov (United States)

    Sukhoivanov, I. A.; Kontar', A. A.; Kublik, A. V.; Makarevich, V. S.

    The paper proposes a method of complex measurements based on the consideration of the parameters of all the elements used in a specific multimode fiber-optic communication line. It is shown that the error in measuring losses in waveguides up to 20 m long can reach a value of 60 percent.

  10. Optical remote sensing measurements of bromine and sulphur emissions: Investigating their potential as tracers of volcanic activity

    OpenAIRE

    Lübcke, Peter

    2014-01-01

    The optical remote sensing of volcanic gas emissions has become an established field in recent decades. The total amount of gas emissions (quantified by measuring the SO2 emission rate) as well as the composition of gases, can help researchers to understand volcanic systems. This knowledge is needed to improve forecasts of volcanic eruptions. For this thesis, volcanic gas emissions were investigated with two different techniques on different time scales. First, high time-resolution (ord...

  11. KrCl lasers for fusion. Final report

    International Nuclear Information System (INIS)

    The lasing characteristics of the Krypton Chloride excimer have been investigated in an e-beam laser facility. The results of experiments have been compared with the predictions of a comprehensive numerical kinetics model. The model predicts that the formation efficiency for KrCl* should be quite high (approx. = 20%) and these predictions appear to be borne out by experimental gain measurements. However, observed intrinsic laser efficiencies are poor, about 1 percent being the best observed in this program. We conclude that the poor lasing performance results from an adverse gain to loss ratio and an extreme sensitivity to optics losses because of the low characteristics magnitude of the gain

  12. Phase equilibria and structural species in NdCl3-NaCl, NdCl3-CaCl2, PrCl3-NaCl, and PrCl3-CaCl2 systems

    International Nuclear Information System (INIS)

    This paper reports that equilibrium phase diagrams for the systems NdCl3---CaCl2 and NdCl3---NaCl were determined by differential thermal analysis. A simple eutectic was observed at 59 ± 1 mol% CaCl2 and 600 degrees ± 2 degrees C in the NdCl3---CaCl2 system. A compound NaCl · 3NdCl3 which melts incongruently at 545 degrees ± 5 degrees C to NdCl3 and a liquid containing approximately 47 mol% NaCl, and a eutectic at 68 mol% NaCl and 439 degrees ± 2 degrees C were found in the NdCl3---NaCl system. On the basis of agreements between the activities calculated by the Clausius-Clapeyron equation and Temkin's model using the present data for the NdCl3---CaCl2 system and the literature data for the PrCl3---CaCl2 system, the melts in the former system consist of Nd3+, Ca2+, and Cl- ions and in the latter system of Pr3+, Ca2+, and Cl- ions. The above approach indicates the presence of Na+, Cl-, and NdCl4- in the NdCl3-rich melts in the NdCl3--NaCl system

  13. Extending the area of investigation of fine versus coarse quartz optical ages from the Lower Danube to the Carpathian Basin

    DEFF Research Database (Denmark)

    Timar-Gabor, Alida; Constantin, Daniela; Marković, S.B.; Jain, Mayank

    2015-01-01

    mm) grains and coarse (63e90 mm) grains respectively. The current study aims at expanding these investigations, both by extending the area of study from the Lower Danube Basin to the Carpathian Basin and by applying time-resolved optically stimulated luminescence (TR-OSL) on quartz, in order to gain...... dose range investigated. A general disagreement between the ages obtained on the two grain sizes for samples with equivalent doses higher than about 100 Gy is reported as in the case of Romanian loess, inferring that the age discrepancy between the two grain sizes might be more widespread than...

  14. The local structure and optical absorption characteristic investigation on Fe doped TiO2 nanoparticles

    CERN Document Server

    Zhao, Tianxing; Huang, Junheng; He, Jinfu; Liu, Qinghua; Pan, Zhiyun; Wu, Ziyu

    2014-01-01

    The local structures and optical absorption characteristic of Fe doped TiO2 nanoparticles synthesized by the sol-gel method were characterized by X-ray Diffraction (XRD), X-ray absorption fine structure spectroscopy (XAFS) and UV-Vis absorption spectroscopy (UV-Vis). XRD patterns show that all Fe-doped TiO2 samples have the characteristic anatase structure. Accurate Fe and Ti K-edge EXAFS analysis further reveal that all Fe atoms replace Ti atoms in the anatase lattice. The analysis of UV-Vis data shows a red shift to the visible range. According to the above results, we claim that substitutional Fe atoms lead to the formation of structural defects and new intermediate energy levels appear, narrowing the band gap and extending the optical absorption edge towards the visible region.

  15. DFT Investigation of Osmium Terpyridinyl Complexes as Potential Optical Limiting Materials

    CERN Document Server

    Alok, Shashwat

    2015-01-01

    The development of optical power limiting materials is important to protect individuals or materials from intense laser irradiation. The photophysical behavior of Os(II) polypyridinyl complexes having aromatic hydrocarbon terpyridyl ligands has received considerable attention as systems exhibiting intramolecular energy transfer to yield a long excited states lifetime. Here we present a focused discussion to illustrate the photophysical behavior of transition metal complexes with modified terpyridyl ligands, utilizing density functional theory. Our DFT studies of the excited state behavior of Os(II) complexes containing pyrene-vinylene derived terpyridine (pyr-v-tpy) ligands can be applied to the development of optical limiting materials controlling the laser power at longer wavelength range.

  16. Pulsed Laser Deposited Nickel Doped Zinc Oxide Thin Films: Structural and Optical Investigations

    Directory of Open Access Journals (Sweden)

    Tanveer A. Dar

    2013-05-01

    Full Text Available Structural and optical studies has been done on Nickel doped Zinc Oxide (NixZn1 – xO, x  0.03, 0.05 and 0.07 by weight thin films prepared by pulsed laser deposition technique. The films are characterized by X-ray diffraction, Uv-vis spectroscopy, X-ray photoelectron spectroscopy. We observed a slight red shift in the optical band gap in the NiZnO subsequent to Ni doping. This shift can be assigned due to the sp-d exchange interaction of Ni- d states with s and p-states of ZnO. Also X-ray photoelectron spectroscopy studies show that Ni has well substituted in + 2 oxidation state by replacing Zn2+.

  17. Theoretical and experimental investigation of optical absorption anisotropy in β-Ga2O3.

    Science.gov (United States)

    Ricci, F; Boschi, F; Baraldi, A; Filippetti, A; Higashiwaki, M; Kuramata, A; Fiorentini, V; Fornari, R

    2016-06-01

    The question of optical bandgap anisotropy in the monoclinic semiconductor β-Ga2O3 was revisited by combining accurate optical absorption measurements with theoretical analysis, performed using different advanced computation methods. As expected, the bandgap edge of bulk β-Ga2O3 was found to be a function of light polarization and crystal orientation, with the lowest onset occurring at polarization in the ac crystal plane around 4.5-4.6 eV; polarization along b unambiguously shifts the onset up by 0.2 eV. The theoretical analysis clearly indicates that the shift in the b onset is due to a suppression of the transition matrix elements of the three top valence bands at Γ point. PMID:26952789

  18. Theoretical and experimental investigation of optical absorption anisotropy in β-Ga2O3

    Science.gov (United States)

    Ricci, F.; Boschi, F.; Baraldi, A.; Filippetti, A.; Higashiwaki, M.; Kuramata, A.; Fiorentini, V.; Fornari, R.

    2016-06-01

    The question of optical bandgap anisotropy in the monoclinic semiconductor β-Ga2O3 was revisited by combining accurate optical absorption measurements with theoretical analysis, performed using different advanced computation methods. As expected, the bandgap edge of bulk β-Ga2O3 was found to be a function of light polarization and crystal orientation, with the lowest onset occurring at polarization in the ac crystal plane around 4.5-4.6 eV polarization along b unambiguously shifts the onset up by 0.2 eV. The theoretical analysis clearly indicates that the shift in the b onset is due to a suppression of the transition matrix elements of the three top valence bands at Γ point.

  19. Investigation on TCP/IP Congestion Control in Optical Burst Switched (OBS Network

    Directory of Open Access Journals (Sweden)

    Ms. Payal Daryani

    2012-03-01

    Full Text Available Transport Control Protocol (TCP is the dominant protocol in modern communication networks, in which the issues of reliability, flow, and congestion control must be handled efficiently. In this review paper an analytical switching is used to exploit the huge bandwidth of optical fibers for future high speed internet backbone. It carries multiple packets, in their turn. Different aggregation schemes have been considered and evaluated.TCP performance greatly depends on the TCP congestion window behavior that is related to loss events occurring in the optical burst switched network, there is a special term called traffic shaping by which we control over the network according to the network load .that means we increase or decrease the send rate according to the network demand.

  20. Optical PIV and LDV Comparisons of Internal Flow Investigations in SHF Impeller

    Directory of Open Access Journals (Sweden)

    G. Wuibaut

    2006-01-01

    Full Text Available The paper presents a comparison between two sets of experimental results in a centrifugal flow pump. The tested impeller is the so-called SHF impeller for which many experimental data have been continuously produced to built databases for CFD code validations with various levels of approximation. Measurements have been performed using optical techniques: 2D particle image velocimetry (PIV technique on an air test model and 2D laser doppler velocimetry (LDV technique on a water model, both for different flow rates. For the present study, results obtained by these optical techniques are compared together in terms of phase averaged velocity and velocity fluctuations inside the impeller flow passage for design flow rate.

  1. Investigation on the optical and electrical properties of MMTG crystal: A Lewis base adduct

    Science.gov (United States)

    Vetha Potheher, I.; Rajarajan, K.; Vimalan, M.; Tamilselvan, S.; Jeyasekaran, R.; Sagayaraj, P.

    2011-09-01

    The growth of nonlinear optical single crystal of manganese mercury thiocyanate glycol monomethyl ether (MMTG), a Lewis base adduct of manganese mercury thiocyanate (MMTC), is reported. MMTG crystallizes in orthorhombic structure with Pca2 1 space group. The optical band gap energy of the sample is found to be 3.5 eV. The sample is thermally stable up to 145 °C. The grown crystal is characterized by photoluminescence, dielectric, dc conductivity, photoconductivity and SEM studies. From the photoluminescence study, the suitability of the material for blue and green light generation is confirmed. The electric and dielectric response of the grown crystal is studied as a function of temperature and the results are discussed. The dc activation energy of the sample is found to be 0.048 eV.

  2. Dynamic focus optical coherence tomography: feasibility for improved basal cell carcinoma investigation

    Science.gov (United States)

    Nasiri-Avanaki, M. R.; Aber, Ahmed; Hojjatoleslami, S. A.; Sira, Mano; Schofield, John B.; Jones, Carole; Podoleanu, A. Gh.

    2012-03-01

    Basal cell carcinoma (BCC) is the most common form of skin cancer. To improve the diagnostic accuracy, additional non-invasive methods of making a preliminary diagnosis have been sought. We have implemented an En-Face optical coherence tomography (OCT) for this study in which the dynamic focus was integrated into it. With the dynamic focus scheme, the coherence gate moves synchronously with the peak of confocal gate determined by the confocal interface optics. The transversal resolution is then conserved throughout the depth range and an enhanced signal is returned from all depths. The Basal Cell Carcinoma specimens were obtained from the eyelid a patient. The specimens under went analysis by DF-OCT imaging. We searched for remarkable features that were visualized by OCT and compared these findings with features presented in the histology slices.

  3. Investigation of a diode-pumped intracavity optical parametric oscillator in pulsed and continuous wave operation

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Skettrup, Torben; Balle-Petersen, O.;

    2001-01-01

    Summary form only given. CW and pulsed compact tunable laser sources in the infrared have widespread scientific, medical and industrial applications. Such a laser source can be obtained by use of a diode-pumped intracavity optical parametric oscillator (IOPO). We report on a IOPO based on a Yb:YA...... lens to generate a beam waist in the PPLN crystal, a dichroic mirror to separate the laser and signal fields and two end mirrors...

  4. Synthesis of MgO Nanoparticles by Solvent Mixed Spray Pyrolysis Technique for Optical Investigation

    OpenAIRE

    Nemade, K. R.; S. A. Waghuley

    2014-01-01

    Solvent mixed spray pyrolysis technique has attracted a global interest in the synthesis of nanomaterials since reactions can be run in liquid state without further heating. Magnesium oxide (MgO) is a category of the practical semiconductor metal oxides, which is extensively used as catalyst and optical material. In the present study, MgO nanoparticles were successfully synthesized using a solvent mixed spray pyrolysis. The X-ray diffraction pattern confirmed the formation of MgO phase with a...

  5. An optical and theoretical investigation of the ultrafast dynamics of a bisthienylethene-based photochromic switch

    OpenAIRE

    Hania, P. R.; Telesca, R.; Lucas, L.N.; Pugzlys, A.; Esch, J.H. van; Feringa, B.L.; Snijders, J. G.; Duppen, K

    2002-01-01

    The switching behavior of 1,2-bis(5-phenyl-2-methylthien-3-yl)cyclopentene is studied by means of polarization selective nonlinear optical spectroscopy and time-dependent density functional theory. The combined information from the observed population and orientational dynamics together with the results of theoretical calculations show that on a subpicosecond time scale rapid mixing and relaxation of electronic states occur, before switching takes place. Such preswitching dynamics was not stu...

  6. Optical PIV and LDV Comparisons of Internal Flow Investigations in SHF Impeller

    OpenAIRE

    Champagne, J. Y.; A. Akhras; M. El Hajem; Bois, G.; G. Wuibaut

    2006-01-01

    The paper presents a comparison between two sets of experimental results in a centrifugal flow pump. The tested impeller is the so-called SHF impeller for which many experimental data have been continuously produced to built databases for CFD code validations with various levels of approximation. Measurements have been performed using optical techniques: 2D particle image velocimetry (PIV) technique on an air test model and 2D laser doppler velocimetry (LDV) technique on a water model, both f...

  7. Optical Waveguide Lightmode Spectroscopic Techniques for Investigating Membrane-Bound Ion Channel Activities

    OpenAIRE

    Székács, Inna; Kaszás, Nóra; Gróf, Pál; Erdélyi, Katalin; Szendrő, István; Mihalik, Balázs; Pataki, Ágnes; Antoni, Ferenc A.; Madarász, Emilia

    2013-01-01

    Optical waveguide lightmode spectroscopic (OWLS) techniques were probed for monitoring ion permeation through channels incorporated into artificial lipid environment. A novel sensor set-up was developed by depositing liposomes or cell-derived membrane fragments onto hydrophilic polytetrafluoroethylene (PTFE) membrane. The fibrous material of PTFE membrane could entrap lipoid vesicles and the water-filled pores provided environment for the hydrophilic domains of lipid-embedded proteins. The se...

  8. Investigation of tolerances of diffractive optical elements for the high power near infrared lasers

    International Nuclear Information System (INIS)

    The deformations due to thermal expansion of a binary diffractive grating in fused silica under near infrared high power laser exposure are estimated by a Finite Element Method. They are compared to the geometrical tolerances obtained by a rigorous electromagnetic method which is used to calculate the optical performances. It is shown that the grating deformations remain below the geometrical tolerances for an average laser power of up to 1 kW and an exposition of up to 100 s

  9. Development and use of compact instruments for tropospheric investigations based on optical spectroscopy from mobile platforms

    OpenAIRE

    Merlaud, Alexis

    2013-01-01

    This thesis presents the development of four different remote-sensing instruments dedicated to atmospheric research and their use in field campaigns between 2008 and 2012. The instruments are based on uv-visible spectrometers and installed respectively on a scientific aircraft (Safire ATR-42), ultralight aircraft, and cars. One of the instruments is targeted to operate from an Unmanned Aerial Vehicle (UAV). The Differential Optical Absorption Spectroscopy (DOAS) technique is used to quantify ...

  10. Optical waveguiding properties into porous gallium nitride structures investigated by prism coupling technique

    International Nuclear Information System (INIS)

    In order to modulate the refractive index and the birefringence of Gallium Nitride (GaN), we have developed a chemical etching method to perform porous structures. The aim of this research is to demonstrate that optical properties of GaN can be tuned by controlling the pores density. GaN films are prepared on sapphire by metal organic chemical vapor deposition and the microstructure is characterized by transmission electron microscopy, and scanning electron microscope analysis. Optical waveguide experiment is demonstrated here to determine the key properties as the ordinary (n0) and extraordinary (ne) refractive indices of etched structures. We report here the dispersion of refractive index for porous GaN and compare it to the bulk material. We observe that the refractive index decreases when the porous density p is increased: results obtained at 0.975 μm have shown that the ordinary index n0 is 2.293 for a bulk layer and n0 is 2.285 for a pores density of 20%. This value corresponds to GaN layer with a pore size of 30 nm and inter-distance of 100 nm. The control of the refractive index into GaN is therefore fundamental for the design of active and passive optical devices

  11. Theoretical investigation of stabilities and optical properties of Si12C12 clusters

    International Nuclear Information System (INIS)

    By sorting through hundreds of globally stable Si12C12 isomers using a potential surface search and using simulated annealing, we have identified low-energy structures. Unlike isomers knit together by Si–C bonds, the lowest energy isomers have segregated carbon and silicon regions that maximize stronger C–C bonding. Positing that charge separation between the carbon and silicon regions would produce interesting optical absorption in these cluster molecules, we used time-dependent density functional theory to compare the calculated optical properties of four isomers representing structural classes having different types of silicon and carbon segregation regions. Absorptions involving charge transfer between segregated carbon and silicon regions produce lower excitation energies than do structures having alternating Si–C bonding for which frontier orbital charge transfer is exclusively from separated carbon atoms to silicon atoms. The most stable Si12C12 isomer at temperatures below 1100 K is unique as regards its high symmetry and large optical oscillator strength in the visible blue. Its high-energy and low-energy visible transitions (1.15 eV and 2.56 eV) are nearly pure one-electron silicon-to-carbon transitions, while an intermediate energy transition (1.28 eV) is a nearly pure carbon-to-silicon one-electron charge transfer

  12. Investigation of Electrical and Optical Properties of Highly Transparent TCO/Ag/TCO Multilayer.

    Science.gov (United States)

    Kim, Sunbo; Lee, Jaehyeong; Dao, Vinh Ai; Ahn, Shihyun; Hussain, Shahzada Qamar; Park, Jinjoo; Jung, Junhee; Lee, Chan; Song, Bong-Shik; Choi, Byoungdeog; Lee, Youn-Jung; Iftiquar, S M; Yi, Junsin

    2015-03-01

    Transparent conductive oxides (TCOs) have been widely used as transparent electrodes for opto-electronic devices, such as solar cells, flat-panel displays, and light-emitting diodes, because of their unique characteristics of high optical transmittance and low electrical resistivity. Among various TCO materials, zinc oxide based films have recently received much attention because they have advantages over commonly used indium and tin-based oxide films. Most TCO films, however, exhibit valleys of transmittance in the wavelength range of 550-700 nm, lowering the average transmittance in the visible region and decreasing short-circuit current (Isc) of solar cells. A TCO/Ag/TCO multi-layer structure has emerged as an attractive alternative because it provides optical characteristics without the valley of transmittance compared with a 100-nm-thick single-layer TCO. In this article, we report the electrical, optical and surface properties of TCO/Ag/TCO. These multi-layers were deposited at room temperature with various Ag film thicknesses from 5 to 15 nm while the thickness of TCO thin film was fixed at 40 nm. The TCO/Ag/TCO multi-layer with a 10-nm-thick Ag film showed optimum transmittance in the visible (400-800 nm) wavelength region. These multi-layer structures have advantages over TCO layers of the same thickness. PMID:26413647

  13. Investigation of interface roughness cross-correlation properties of optical thin films from total scattering losses

    International Nuclear Information System (INIS)

    The interface roughness and interface roughness cross-correlation properties affect the scattering losses of high-quality optical thin films. In this paper, the theoretical models of light scattering induced by surface and interface roughness of optical thin films are concisely presented. Furthermore, influence of interface roughness cross-correlation properties to light scattering is analyzed by total scattering losses. Moreover, single-layer TiO2 thin film thickness, substrate roughness of K9 glass and ion beam assisted deposition (IBAD) technique effect on interface roughness cross-correlation properties are studied by experiments, respectively. A 17-layer dielectric quarter-wave high reflection multilayer is analyzed by total scattering losses. The results show that the interface roughness cross-correlation properties depend on TiO2 thin film thickness, substrate roughness and deposition technique. The interface roughness cross-correlation properties decrease with the increase of film thickness or the decrease of substrates roughness. Furthermore, ion beam assisted deposition technique can increase the interface roughness cross-correlation properties of optical thin films. The measured total scattering losses of 17-layer dielectric quarter-wave high reflection multilayer deposited with IBAD indicate that completely correlated interface model can be observed, when substrate roughness is about 2.84 nm.

  14. Investigation and experimental validation of the contribution of optical interconnects in the SYMPHONIE massively parallel computer

    International Nuclear Information System (INIS)

    Progress in microelectronics lead to electronic circuits which are increasingly integrated, with an operating frequency and an inputs/outputs count larger than the ones supported by printed circuit board and back-plane technologies. As a result, distributed systems with several boards cannot fully exploit the performance of integrated circuits. In synchronous parallel computers, the situation is worsen since the overall system performances rely on the efficiency of electrical interconnects between the integrated circuits which include the processing elements (PE). The study of a real parallel computer named SYMPHONIE shows for instance that the system operating frequency is far smaller than the capabilities of the microelectronics technology used for the PE implementation. Optical interconnections may cancel these limitations by providing more efficient connections between the PE. Especially, free-space optical interconnections based on vertical-cavity surface-emitting lasers (VCSEL), micro-lens and PIN photodiodes are compatible with the required features of the PE communications. Zero bias modulation of VCSEL with CMOS-compatible digital signals is studied and experimentally demonstrated. A model of the propagation of truncated gaussian beams through micro-lenses is developed. It is then used to optimise the geometry of the detection areas. A dedicated mechanical system is also proposed and implemented for integrating free-space optical interconnects in a standard electronic environment, representative of the one of parallel computer systems. A specially designed demonstrator provides the experimental validation of the above physical concepts. (author)

  15. Optical bleaching of BaFCl crystals X-irradiated at room temperature

    International Nuclear Information System (INIS)

    The optical bleaching behaviour of the optical absorption bands produced by X-irradiation is investigated by paying particular attention to the difference between the two types of F centers in the BaFCl crystals. The optical bleachings are performed using a Xe-lamp. The optical absorption spectra and changes in the absorption bands during bleaching with F(Cl-) and F(F-) light are given and discussed

  16. Investigation of electrical and optical properties of MEH-PPV: ZnO nanocomposite films for OLED applications

    Science.gov (United States)

    Azhar, N. E. A.; Shafura, A. K.; Affendi, I. H. H.; Shariffudin, S. S.; Saurdi, I.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.

    2016-07-01

    Recent investigations of the promising materials for optoelectronic have been demonstrated by introducing n-type inorganic material into conjugated polymer. The optical and electrical of nanocomposite films based on poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and zinc oxide (ZnO) nanostructured of various deposition layers (1 to 3 layers) have been investigated. The MEH-PPV: ZnO nanocomposite films were deposited using spin-coating technique. The surface morphology nanocomposite films were characterized using field emission scanning electron microscope. From surface profiler measurement, we found that the thickness of nanocomposite films increased as deposition time increased. The optical properties were measured using photoluminescence spectroscope. The photoluminescence (PL) spectra showed that two deposition layers is the highest intensity at visible region (green emission) due to high energy transfer from particles to the polymer. The current density for two layers sample is due to aggregation of conjugated polymer chain hence form excited interchain exciton for optical excitation. This study will provide better performance and suitable for optoelectronic device especially OLEDs application.

  17. Investigation of third-order optical nonlinearity in KBe2BO3F2 crystal by Z-scan

    Science.gov (United States)

    Li, F.-Q.; Zong, N.; Zhang, F.-F.; Yang, J.; Yang, F.; Peng, Q.-J.; Cui, D.-F.; Zhang, J.-Y.; Wang, X.-Y.; Chen, C.-T.; Xu, Z.-Y.

    2012-08-01

    The third-order optical nonlinearity of deep-ultraviolet (DUV) nonlinear optical (NLO) crystal KBe2BO3F2 (KBBF) was investigated using single-beam Z-scan technique for the first time. The Z-scans were performed on a c-cut KBBF crystal and a KBBF prism-coupling device (PCD) with picosecond pulses at 355 nm. No two-photon absorption was observed in the experiment. The measured nonlinear refraction index n 2 showed positive signs, indicating self-focusing Kerr effects. The n 2 values were estimated to be (1.75±0.35)×10-15 cm2/W with the c-cut sample and (1.85±0.37)×10-15 cm2/W with the PCD, corresponding to the third-order nonlinear optical susceptibilities χ_{eff}^{(3)} of (0.99±0.20)×10-13 esu and (0.94±0.19)×10-13 esu, respectively. The results are expected to promote the investigation of frequency conversion processes with ultra-short laser in KBBF crystal.

  18. SCC investigation of low alloy ultra-high strength steel 30CrMnSiNi2A in 3.5wt%NaCl solution by slow strain rate technique

    Institute of Scientific and Technical Information of China (English)

    Liu Jianhua; Guo Qiang; Yu Mei; Li Songmei

    2014-01-01

    To evaluate stress corrosion cracking (SCC) mechanism of low alloy ultra-high strength steel 30CrMnSiNi2A in environment containing NaCl, SCC behavior of the steel in 3.5wt%NaCl solution is investigated by slow strain rate technique (SSRT) with various strain rates and applied potentials, surface analysis technique, and electrochemical measurements. SCC susceptibility of the steel increases rapidly with strain rate decreasing from 1 · 10?5 s?1 to 5 · 10?7 s?1, and becomes stable when strain rate is lower than 5 · 10?7 s?1. SCC propagation of the steel in the solution at open circuit potential (OCP) needs sufficient hydrogen which is supplied at a certain strain rate. Fracture surface at OCP has similar characteristics with that at cathodic polarization ?1000 mVSCE, which presents characteristic fractography of hydrogen induced cracking (HIC). All of these indicate that SCC behavior of the steel in the solution at OCP is mainly controlled by HIC rather than anodic dissolution (AD).

  19. EPR spectroscopy as a tool for investigation of differences in radical status in wheat plants of various tolerances to osmotic stress induced by NaCl and PEG-treatment.

    Science.gov (United States)

    Labanowska, Maria; Filek, Maria; Kurdziel, Magdalena; Bidzińska, Ewa; Miszalski, Zbigniew; Hartikainen, Hélina

    2013-01-15

    Two kinds of wheat genotypes with different tolerance to osmotic stress (NaCl and PEG-treatment) were investigated with biochemical analyses, including the measurements of total antioxidant capacity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, reducing power and starch content. The results were compared with electron paramagnetic resonance (EPR) data concerning the nature and amounts of stable long lived radicals present in the control and stressed plants. In addition, the changes in manganese content upon stress conditions were monitored. Different mechanisms of protection against PEG stress in sensitive and tolerant wheat genotypes were postulated. In sensitive genotypes, electrons were created in excess in stress conditions, and were stabilized by polysaccharide molecules, whereas in tolerant genotypes, protection by antioxidants dominated. Moreover, the quinone-semiquinone balance shifted towards semiquinone, which became the place of electron trapping. NaCl-treatment yielded significant effects mainly in sensitive genotypes and was connected with the changes of water structure, leading to inactivation of reactive oxygen species by water molecules. PMID:23141807

  20. SCC investigation of low alloy ultra-high strength steel 30CrMnSiNi2A in 3.5wt% NaCl solution by slow strain rate technique

    Directory of Open Access Journals (Sweden)

    Liu Jianhua

    2014-10-01

    Full Text Available To evaluate stress corrosion cracking (SCC mechanism of low alloy ultra-high strength steel 30CrMnSiNi2A in environment containing NaCl, SCC behavior of the steel in 3.5wt% NaCl solution is investigated by slow strain rate technique (SSRT with various strain rates and applied potentials, surface analysis technique, and electrochemical measurements. SCC susceptibility of the steel increases rapidly with strain rate decreasing from 1 × 10−5 s−1 to 5 × 10−7 s−1, and becomes stable when strain rate is lower than 5 × 10−7 s−1. SCC propagation of the steel in the solution at open circuit potential (OCP needs sufficient hydrogen which is supplied at a certain strain rate. Fracture surface at OCP has similar characteristics with that at cathodic polarization −1000 mVSCE, which presents characteristic fractography of hydrogen induced cracking (HIC. All of these indicate that SCC behavior of the steel in the solution at OCP is mainly controlled by HIC rather than anodic dissolution (AD.

  1. Recycling Of Bomb Produced Cl 36

    Science.gov (United States)

    Lazarev, V.; Blinov, A.; Huber, Th.; Kubo, F.; Nolte, E.

    The success of accelerated mass-spectrometry (AMS) has allowed the measuring of very small quantities of radioactive nuclides with the ratio to their stable isotope up to 10-14. With the help of this method the concentration of 36Cl in natural samples can be investigated. The main sources of 36Cl in the atmosphere are a) The natural production in nuclear reactions induced by the interaction of high energy cosmic rays with atmospheric Ar. b) The production by the interaction of high neutron fluxes emitted by the nuclear weapon tests with stable chlorine. c) The production in different reactors with the following release (e.g. Chernobyl accident). The analysis of 36Cl time profile in Greenland showed the fast removal of chlorine from the atmosphere so that nowadays only the natural production of 36Cl is of importance. However the measurement of 36Cl in modern precipitation revealed the significant excess of its concentration over the simulated predictions. The recycling of chlorine as an explanation of the observed discrepancy is ar- gued. The biosphere could take up a part of the fallen down bomb produced 36Cl and releases it into the troposphere in the form of CH3Cl. To check the hypothesis the experiment to collect methyl chloride from the air and to measure 36Cl was set up. The high observed ratio 36 Cl/Cl proves that the chlorine recycling really takes place. Additionally, in order to get more information about the distribution of 36Cl the measurements of its concentration in lakes with long flushing times were performed. With the help of modeling the different sources of 36Cl can be distinguished. The dominant source of 36Cl in many Alpine lakes is chlorine, released during the accident on the Chernobyl nuclear power plant.

  2. Investigation of the structural and electronic properties of quantum well superlattices made of CuCl, CuBr and CuI

    International Nuclear Information System (INIS)

    This paper reports first principle investigations of structural and electronic properties of both bulk and superlattice (SL) systems of cuprous halides. The obtained structural data for bulks compares well with literature while data for SL is not compared because unavailable (to our knowledge). The electronic structure of bulks and also of (001) and (110) growth axis superlattices (SLs) are calculated and it is shown that at the reverse of the IV-IV and III-V systems, the (110) growth axis impacts the electronic structure which indicates a great influence of the d-orbital. (author)

  3. Optical and thermal investigations on vanadyl doped zinc lithium borate glasses

    Directory of Open Access Journals (Sweden)

    Seema Dalal

    2015-09-01

    Full Text Available Using standard melt-quench technique, transition metal oxide (2 mol% of V2O5 doped glasses having composition xZnO·(30 − xLi2O·70B2O3 (x = 0, 2, 5, 7 and 10 are prepared. The density (D is measured using buoyancy and found to be lying between 2.21 and 2.45 g/cm3 with an increasing trend on substituting ZnO contents in place of Li2O. The theoretical optical basicity (Λth is calculated and found to increase with increasing inclusion of ZnO indicating an increase in the ionic character. The molar refraction (Rm, refractive index (nr and molar polarizability (αm are calculated and explained on the basis of structural changes. The optical absorption spectra have been used to evaluate the values of optical band gap (Eopt and band tailing parameter (B. It is observed that Eopt decreases with the increasing contents of ZnO in base glass matrix. The decrease in Eopt is an evidence of enhancement in the number of non-bridging oxygen atoms (NBOs thereby increasing the four-coordinated boron atoms. The as-quenched samples in bulk form are subjected to differential thermal analysis (DTA to assess the glass transition temperature (Tg, which is 476 °C for pure lithium borate glass. The variations suggest that the structure is being modified by the substitution of ZnO.

  4. Saturation curves of two-color laser-induced incandescence measurements for the investigation of soot optical properties

    Science.gov (United States)

    Migliorini, F.; De Iuliis, S.; Maffi, S.; Zizak, G.

    2015-09-01

    Two-color laser-induced incandescence (LII) measurements are carried out in diffusion flames and at the exhaust of a homemade soot generator, both fueled with ethylene and methane. Two-color prompt LII signals, their ratio and the corresponding temperature have been analyzed as a function of laser fluence. In particular, the effect of fuel, soot load and gas/particle initial temperature on LII measurements have been investigated. LII spectral measurements have also been performed in all conditions for validation. The results suggest that the incandescence is sensitive to both optical and non-optical physical properties of the particles. Moreover, soot volume fraction measurements are dependent on the laser fluence used, indicating that the soot temperature influences the refractive index absorption function. Such issues can be overcome by working at high laser fluences, where the saturation curves are independent from the experimental conditions if the soot absorption function near soot sublimation threshold is known.

  5. Investigating the nature of the Fried Egg nebula: CO mm-line and optical spectroscopy of IRAS 17163-3907

    CERN Document Server

    Wallström, Sofia H J; Lagadec, E; Black, J H; Oudmaijer, R D; Justtanont, K; van Winckel, H; Zijlstra, A A

    2015-01-01

    Through CO mm-line and optical spectroscopy, we investigate the properties of the Fried Egg nebula IRAS 17163-3907, which has recently been proposed to be one of the rare members of the yellow hypergiant class. The CO J=2-1 and J=3-2 emission arises from a region within 20" of the star and is clearly associated with the circumstellar material. The CO lines show a multi-component asymmetrical profile, and an unexpected velocity gradient is resolved in the east-west direction, suggesting a bipolar outflow. This is in contrast with the apparent symmetry of the dust envelope as observed in the infrared. The optical spectrum of IRAS 17163-3907 between 5100 and 9000 {\\AA} was compared with that of the archetypal yellow hypergiant IRC+10420 and was found to be very similar. These results build on previous evidence that IRAS 17163-3907 is a yellow hypergiant.

  6. Investigation of ultracold atoms and molecules in a dark magneto-optical trap

    Institute of Scientific and Technical Information of China (English)

    Wang Li-Rong; Ji Zhong-Hua; Yuan Jin-Peng; Yang Yan; Zhao Yan-Ting; Ma Jie; Xiao Lian-Tuan; Jia Suo-Tang

    2012-01-01

    In this paper,ultracold atoms and molecules in a dark magneto-optical trap (MOT) are studied via depumping the cesium cold atoms into the dark hyperfine ground state.The collision rate is reduced to 0.45 s-1 and the density of the atoms is increased to 5.6 × 1011 cm-3 when the fractional population of the atoms in the bright hyperfine ground state is as low as 0.15.The vibrational spectra of the ultracold cesium molecules are also studied in a standard MOT and in a dark MOT separately.The experimental results are analyzed by using the perturbative quantum approach.

  7. An Optical and Computational Investigation on the Effects of Transient Fuel Injections in Internal Combustion Engines

    Science.gov (United States)

    Neal, Nicholas

    The effects of transient rate-of-injection profiles on high-pressure fuel jets have been studied in an optically accessible internal combustion engine. High-speed optical imaging measurements were applied over a range of ambient conditions, fuel types, and injection parameters. The optical data demonstrate that during the early part of the injection, while the liquid core of the jet is disintegrating, penetration is functionally linked to the orifice exit velocity up until a downstream distance hypothesized to be the jet breakup length. The jets then transition to a mixing dominated penetration behavior further downstream. Therefore, for cases that exhibit transient rate-of-injection (ROI) profiles, quasi-steady correlations for penetration have poor agreement with the empirical data. The lack of agreement between models using quasi-steady approximations and the high-speed experimental data, and the experimental evidence of liquid core physics impacting the transient jet penetration, motivated the development of a new 1-D model that integrates liquid core penetration physics and eliminates quasi-steady approximations. The new 1-D modeling methodology couples the transport equations for the evolution of the liquid core of the jet and the surrounding sheath of droplets resulting from breakup. The results of the model are validated against the aforementioned optical transient jet measurements. Finally, experimental results for two jet fuels and a diesel fuel are studied with the aid of the model. Differences in fuel properties cause the diesel fuel jet to transition from an incomplete spray to a complete spray later than the jet fuels during the transient injection process. Increasing ambient density causes the transition to happen earlier during the injection transient for all three fuels. The ignition delay and liftoff length appeared to be relatively unaffected by the late transition from incomplete to complete spray at low ambient density and low injection

  8. Investigations of intensity dependant nonlinear optical properties of betanin/ZnO composites embedded in PVA

    Science.gov (United States)

    Thankappan, Aparna; Nampoori, V. P. N.; Thomas, Sabu

    2016-09-01

    In this report, we report the intensity dependant nonlinear absorption properties of bio-inspired hybrid materials (betanin-ZnO) embedded in polymeric matrices through the Z-scan technique using an Nd: YAG laser (532 nm, 7 ns, 10 Hz). We observed a change over in the sign of nonlinearity due to the interplay of exciton bleaching and optical limiting mechanisms. Light confinement effect and ship-in-a bottle effect play crucial roles. Theoretical analysis has been performed using a model based on nonlinear absorption coefficient and saturation intensity. The result of present study gives an additional mechanism for the gain enhancement in dye doped ZnO matrix.

  9. Occlusal overload investigations by noninvasive technology: fluorescence microscopy and en-face optical coherence tomography

    Science.gov (United States)

    Marcauteanu, Corina; Negrutiu, Meda; Sinescu, Cosmin; Demjan, Enikö; Hughes, Michael; Bradu, Adrian; Dobre, George; Podoleanu, Adrian G.

    2009-07-01

    The aim of this study is the early detection and monitoring of occlusal overload in bruxing patients. En-Face Optical coherence tomography (eF-OCT) and fluorescence microscopy (FM) were used for the imaging of several anterior teeth extracted from patients with light active bruxism. We found a characteristic pattern of enamel cracks, that reached the tooth surface. We concluded that the combination of the en-Face OCT and FM is a promising non-invasive alternative technique for reliable monitoring of occlusal overload.

  10. Further investigations into pulsed optically stimulated luminescence from feldspars using blue and green light

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Jain, Mayank; Kalchgruber, R.;

    2009-01-01

    -resolved optically stimulated luminescence (TR-OSL), and these signals can be mathematically described as a sum of 4 exponential components (a, b, c, d). The slowest component, d, increases with the duration of the light pulse as expected from the exponential model. The stimulation temperature dependence experiment...... suggests that the TR-OSL signal decay is governed by the recombination process and not by the excited state lifetime. Furthermore data from the TR-OSL signal dependence on stimulation time and preheat temperature suggest that the recombination process may not be a sum of exponentials, although the model...... cannot be rejected definitively....

  11. Investigation of a diode-pumped intracavity optical parametric oscillator in pulsed and continuous wave operation

    OpenAIRE

    Jensen, Ole Bjarlin; Skettrup, Torben; Balle-Petersen, O.; Bruun-Larsen, M.

    2001-01-01

    Summary form only given. CW and pulsed compact tunable laser sources in the infrared have widespread scientific, medical and industrial applications. Such a laser source can be obtained by use of a diode-pumped intracavity optical parametric oscillator (IOPO). We report on a IOPO based on a Yb:YAG laser incorporating a periodically poled LiNbO3 (PPLN) crystal inside the laser cavity to take advantage of the high circulating intracavity field. The Yb:YAG crystal is pumped by a reliable 940 nm ...

  12. LDEF (Flight), S0050 : Investigation of the Effects of Long-Duration Exposure on Active Optical Syst

    Science.gov (United States)

    1990-01-01

    LDEF (Flight), S0050 : Investigation of the Effects of Long-Duration Exposure on Active Optical System Components, Tray E05 The flight photograph was taken from the Orbiter aft flight deck during the LDEF retrieval and prior to berthing the LDEF in the Orbiter cargo bay. The Active Optical System Component Experiment (S0050) contained 136 test specimen located in a six (6) inch deep LDEF peripheral experiment tray. The complement of specimen included optical and electro-optical components, glasses and samples of various surface finishes. The experiment tray was divided into six sections, each consisting of a 1/4 inch thick chromic anodized aluminum base plate and a 1/16th inch thick aluminum hat-shaped structure for mounting the test specimens. The test specimens were typically placed in fiberglass-epoxy retainer strip assemblies prior to installation on the hat-shaped mounting structure. Five of the six sections were covered by a 1/8 inch thick anodized aluminum sun screen with openings that allowed 56 percent transmission over the central region. Two sub-experiments, The Optical Materials and UV Detectors Experiment (S0050-01) consist of 15 optical windows, filters and detectors and occupies one of the trays six sub-sections and The Optical Substrates and Coatings Experiment (S0050-02 ) that includes 12 substrates and coatings and two secondary experiments,The Holographic Data Storage Experiment (AO044) consisting of four crystals of lithium niobate and ThePyroelectric Infrared Detectors Experiment (AO135) with twenty detectors, are also mounted in the integrated tray. The experiment structure was assembled with non-magnetic stainless steel fasteners. The experiment hardware appears to be intact with no apparent damage. The excess blue color in the photograph makes a detailed assessment of color changes difficult. The paint dots on the tray clamp blocks, initially white, appear to have darkened and tray flanges appear discolored. The experiment sun screens and

  13. The optical band gap investigation of PVP-capped ZnO nanoparticles synthesized by sol-gel method

    Science.gov (United States)

    Yuliah, Yayah; Bahtiar, Ayi; Fitrilawati, Siregar, Rustam E.

    2016-02-01

    ZnO Nanoparticles (NPs) has unique natures on their crystal structure, direct band gap and high exciton binding energy, consequently applied in optoelectronic devices such as solar cells, optical wave guide and light emitting diodes (LED). However the drawback was ZnO NPs tend to agglomerate and turn to nano-structured materials with poor properties. Effort to avoid agglomerations generally resolved by surface modification of ZnO NPs to obtain well-dispersed suspension. However changes in the surface of ZnO NPs may change the electronic structure and density of states of ZnO NPs, in turn may change the optical band gap. Thus, the objective of current research is investigation of optical band gap of ZnO NPs due to surface modification by capping agent of poly-4-vinylpyrrolidone (PVP) molecules. Uncapped and PVP-capped ZnO nanoparticles were prepared by sol-gel method. The characteristics of surface modifications were investigated by UV-Vis and Photo Luminescence spectroscopy and Transmission Electron Microscope (TEM). The results shows the surface modification has change the band gap of ZnO NPs obtained at second precipitated stage. In contrast, the change of the optical band gap did not observe due to the surface modification of ZnO NPs obtained at the first stage. It was concluded that PVP capping on ZnO NPs did not affect on the band gap when the capping was performed on first stage. It is emphasized that this statement also supported by TEM images observations.

  14. Investigations of high-speed optical transmission systems employing Absolute Added Correlative Coding (AACC)

    Science.gov (United States)

    Dong-Nhat, Nguyen; Elsherif, Mohamed A.; Malekmohammadi, Amin

    2016-07-01

    A novel multilevel modulation format based on partial-response signaling called Absolute Added Correlative Coding (AACC) is proposed and numerically demonstrated for high-speed fiber-optic communication systems. A bit error rate (BER) estimation model for the proposed multilevel format has also been developed. The performance of AACC is examined and compared against other prevailing On-Off-Keying and multilevel modulation formats e.g. non-return-to-zero (NRZ), 50% return-to-zero (RZ), 67% carrier-suppressed return-to-zero (CS-RZ), duobinary and four-level pulse-amplitude modulation (4-PAM) in terms of receiver sensitivity, spectral efficiency and dispersion tolerance. Calculated receiver sensitivity at a BER of 10-9 and chromatic dispersion tolerance of the proposed system are ∼-28.3 dBm and ∼336 ps/nm, respectively. The performance of AACC is delineated to be improved by 7.8 dB in terms of receiver sensitivity compared to 4-PAM in back-to-back scenario. The comparison results also show a clear advantage of AACC in achieving longer fiber transmission distance due to the higher dispersion tolerance in optical access networks.

  15. Modeling and experimental investigation of an integrated optical microheater in silicon-on-insulator.

    Science.gov (United States)

    Kaushal, Saket; Das, Bijoy Krishna

    2016-04-10

    A linear piecewise model has been formulated to analyze the performance of a metallic microheater integrated with single-mode waveguides (λ∼1550  nm) in silicon-on-insulator (SOI). The model has been used to evaluate integrated optical microheaters fabricated in a SOI substrate with 2 µm device layer thickness. The Fabry-Perot modulation technique has been used to extract the effective thermo-optic phase shift and response time. The effective thermal power budget of Peff,π∼500  µW (out of actually consumed power Pπ=1.1  mW) for a π phase shift and a switching time of τ∼9  µs, have been recorded for a typical Ti heater stripe of length LH=50  µm, width WH=2  µm, and thickness tH∼150  nm, integrated with a Fabry-Perot waveguide cavity of length ∼20  mm. It has been shown that the performance of a heater improves (in terms of power budget) as the length of a microheater decreases. However, smaller heater size requires higher joule heating to obtain a desired phase shift, which is again found to be dependent on polarization of the guided mode because of thermal stress. PMID:27139842

  16. Spectroellipsometric investigation of optical, morphological, and structural properties of reactively sputtered polycrystalline AlN films

    International Nuclear Information System (INIS)

    The optical and morphological properties of reactively sputtered AlN films on Si substrates have been studied in this work from a self-consistent three-layer optical model developed from spectroscopic-ellipsometry analysis and validated by observations from transmission-electron microscopy, Auger electron spectroscopy, and in situ reflectance interferometry. These properties correlate to the film microstructural properties. Accordingly, the almost thickness-independent refractive index of 2.01 of the bulk AlN layer indicates its polycrystalline microstructure. This layer also appears ungraded, homogeneous, isotropic, and free of excess Al, as if grown through a steady process. The small film absorption points to the Urbach tail states produced by the structural disorder typical of such sputtered films. The films' interface layer consists of a graded Bruggeman intermix of outdiffused Si and AlN materials spreading over 10-12 nm thickness. The surface morphology includes an Al2O3-oxidized outer rough surface gradually becoming AlN bulk with diminishing amounts of Al2O3 and inner pores. The increase in the surface-layer thickness, as the film grows, indicates further surface roughening due to enlarging crystals in a disoriented growth. This spectroscopic-ellipsometry analysis of AlN films has allowed us to study the effect of substrate biasing on the AlN microstructure and to place forward a new processing method for the surface smoothening of rough AlN and diamond films.

  17. A theoretical investigation of generalized grating imaging and its application to optical encoders

    Science.gov (United States)

    Ye, Guoyong; Liu, Hongzhong; Fan, Shanjin; Li, Xuan; Yu, Haoyu; Lei, Biao; Shi, Yongsheng; Yin, Lei; Lu, Bingheng

    2015-11-01

    Since optical encoders based on generalized grating imaging are more compact and robust than conventional Moiré encoders, they are preferable to be installed in industrial systems. To some extent, the measurement resolution and accuracy are limited by harmonic distortion of the encoder signals. In this work, an analysis of the pseudoimaging formation in a system including one grating illuminated by a point light source is firstly performed using a scalar Fresnel approach. Then, we analyze an optical encoder with a double grating configuration by considering the slits of the index grating as an array of point light source and considering the pseudoimages at the observation plane as superposition of the pseudoimages formed by each point light source. Conditions for the locations and contrast of the pseudoimages are derived. It shows that sufficient signal amplitude can be obtained at Talbot planes allowing a relative large gap tolerance. In particular, the harmonic distortion of the pseudoimages is analyzed and conditions for eliminating or suppressing the harmonic components are studied. The simulation results indicate that the n-th order harmonic component can be eliminated by setting the size of the slits of the index grating to be 2p1/n, where p1 is the period of the scale grating. Moreover, the dominant 3rd order harmonic component can also be suppressed by setting the aperture ratio of the scale grating to be 72.2%.

  18. Fabricating silver nanoplate/hybrid silica gel glasses and investigating their nonlinear optical absorption behavior

    Science.gov (United States)

    Zheng, Chan; Wenzhe, Chen; Xiaoyun, Ye; Cai, Shuguang; Xiao, Xueqing

    2014-03-01

    Silver nanoplate/hybrid silica gel glasses were prepared via the sol-gel technique. Analysis of ultraviolet-visible spectroscopy extinction spectra confirmed the successful incorporation of silver nanoplates into the hybrid silica gel glasses. The silver nanoplate/hybrid silica gel glass composites are completely noncrystalline because of their low doping level compared with that of the silica matrix. The nonlinear optical absorption behavior of the silver nanoplate/hybrid silica gel glass composites was studied via open-aperture Z-scan technique with 4 ns pulse durations at 532 nm and 1064 nm. The nonlinear optical properties of silver nanoplates are maintained after they were introduced into silica gel glasses. Furthermore, the silver nanoplate/hybrid silica gel glasses exhibit intensity-dependent transformation from saturable absorption (SA) to reverse saturable absorption (RSA). The SA behavior at low excitation intensity can be attributed to the bleaching of ground-state surface plasmon resonance absorption induced by the retarded electronic relaxation process in solid-state gel glasses. By contrast, the RSA at high incident influence may have resulted from excited-state absorption and two-photon absorption.

  19. Investigations of the optical fields of 3CR radio sources to faint limiting magnitudes

    International Nuclear Information System (INIS)

    A deep optical survey of the fields of 18 3CR radio sources has been carried out with the Hale 5-m telescope, using a prototype charged-coupled device as a detector. These sources were among the few 3CR objects which were either previously unidentified or associated with very faint images at the plate limit for which confirmation was required. Ten new identifications are proposed, and candidates for the remaining eight sources are confirmed. Of these identifications, four are considered provisional, since they are displaced from the radio source axes. In addition, the candidate for one is classed as a confirmed identification, although the optical field is crowded and an unambiguous identification cannot be made on positional arguments alone. A subsample of 60 sources from the 3CR catalogue, considered by previous workers, is now (provisionally) completely identified. These new results are used to construct luminosity distributions at S(178) >= 20 Jy and S(178) >= 10 Jy, and the implications of the complete identification rate for models of source evolution formulated by other workers are examined. (author)

  20. Investigation into spiral phase plate contrast in optical and electron microscopy

    CERN Document Server

    Juchtmans, Roeland; Lubk, Axel; Verbeeck, Jo

    2016-01-01

    The use of phase plates in the back focal plane of a microscope is a well established technique in optical microscopy to increase the contrast of weakly interacting samples and is gaining interest in electron microscopy as well. In this paper we study the spiral phase plate (SPP), also called helical, vortex, or two-dimensional Hilbert phase plate, that adds an angularly dependent phase of the form $e^{i\\ell\\phi}$ to the exit wave in Fourier space. In the limit of large collection angles, we analytically calculate that the average of a pair of $\\ell=\\pm1$ SPP images is directly proportional to the gradient squared of the exit wave, explaining the edge contrast previously seen in optical SPP work. The difference between a clockwise-anticlockwise pair of SPP images and conditions where this difference vanishes and the gradient of the exit wave can be seen from one single SPP image, are discussed. Finally, we demonstrate how with three images, one without and one with each of an $\\ell=\\pm1$ SPP, may give enough ...

  1. Tensile stress generation by optical breakdown in tissue: Experimental investigations and numerical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, A. [Medizinisches Laserzentrum Luebeck (Germany); Scammon, R.J.; Godwin, R.P. [Los Alamos National Lab., NM (United States)

    1999-03-01

    Biological tissue is more susceptible to damage from tensile stress than to compressive stress. Tensile stress may arise through the thermoelastic response of laser-irradiated media. Optical breakdown, however, has to date been exclusively associated with compressive stress. The authors show that this is appropriate for water, but not for tissues for which the elastic-plastic material response needs to be considered. The acoustic transients following optical breakdown in water and cornea were measured with a fast hydrophone and the cavitation bubble dynamics, which is closely linked to the stress wave generation, was documented by flash photography. Breakdown in water produced a monopolar acoustic signal and a bubble oscillation in which the expansion and collapse phases were symmetric. Breakdown in cornea produced a bipolar acoustic signal coupled with a pronounced shortening of the bubble expansion phase and a considerable prolongation of its collapse phase. The tensile stress wave is related to the abrupt end of the bubble expansion. Numerical simulations using the MESA-2D code were performed assuming elastic-plastic material behavior in a wide range of values for the shear modulus and yield strength. The calculations revealed that consideration of the elastic-plastic material response is essential to reproduce the experimentally observed bipolar stress waves. The tensile stress evolves during the outward propagation of the acoustic transient and reaches an amplitude of 30--40% of the compressive pulse.

  2. Investigation of a Cross-Correlation Based Optical Strain Measurement Technique for Detecting radial Growth on a Rotating Disk

    Science.gov (United States)

    Clem, Michelle M.; Woike, Mark R.

    2013-01-01

    The Aeronautical Sciences Project under NASA`s Fundamental Aeronautics Program is extremely interested in the development of novel measurement technologies, such as optical surface measurements in the internal parts of a flow path, for in situ health monitoring of gas turbine engines. In situ health monitoring has the potential to detect flaws, i.e. cracks in key components, such as engine turbine disks, before the flaws lead to catastrophic failure. In the present study, a cross-correlation imaging technique is investigated in a proof-of-concept study as a possible optical technique to measure the radial growth and strain field on an already cracked sub-scale turbine engine disk under loaded conditions in the NASA Glenn Research Center`s High Precision Rotordynamics Laboratory. The optical strain measurement technique under investigation offers potential fault detection using an applied high-contrast random speckle pattern and imaging the pattern under unloaded and loaded conditions with a CCD camera. Spinning the cracked disk at high speeds induces an external load, resulting in a radial growth of the disk of approximately 50.0-im in the flawed region and hence, a localized strain field. When imaging the cracked disk under static conditions, the disk will be undistorted; however, during rotation the cracked region will grow radially, thus causing the applied particle pattern to be .shifted`. The resulting particle displacements between the two images will then be measured using the two-dimensional cross-correlation algorithms implemented in standard Particle Image Velocimetry (PIV) software to track the disk growth, which facilitates calculation of the localized strain field. In order to develop and validate this optical strain measurement technique an initial proof-of-concept experiment is carried out in a controlled environment. Using PIV optimization principles and guidelines, three potential speckle patterns, for future use on the rotating disk, are developed

  3. Radiative forcing calculations for CH3Cl

    International Nuclear Information System (INIS)

    Methyl chloride, CH3Cl, is the major natural source of chlorine to the stratosphere. The production of CH3Cl is dominated by biological sources from the oceans and biomass burning. Production has a seasonal cycle which couples with the short lifetime of tropospheric CH3Cl to produce nonuniform global mixing. As an absorber of infrared radiation, CH3Cl is of interest for its potential affect on the tropospheric energy balance as well as for its chemical interactions. In this study, we estimate the radiative forcing and global warming potential (GWP) of CH3Cl. Our calculations use an infrared radiative transfer model based on the correlated k-distribution algorithm for band absorption. Global and annual average vertical profiles of temperature and trace gas concentration were assumed. The effects of clouds are modeled using three layers of global and annual average cloud optical properties. A radiative forcing value of 0.0053 W/m2ppbv was obtained for CH3Cl and is approximately linear in the background abundance. This value is about 2 percent of the forcing of CFC-11 and about 300 times the forcing of CO2, on a per molecule basis. The radiative forcing calculation for CH3Cl is used to estimate the global warming potential (GWP) of CH3Cl. The results give GWPs for CH3Cl of the order of 25 at a time of 20 years(CO2 = 1). This result indicates that CH3Cl has the potential to be a major greenhouse gas if significant human related emissions were introduced into the atmosphere

  4. Investigation of quadratic electro-optic effects and electro-absorption process in GaN/AlGaN spherical quantum dot

    OpenAIRE

    Kouhi, Mohammad; Vahedi, Ali; Akbarzadeh, Abolfazl; Hanifehpour, Younes; Joo, Sang Woo

    2014-01-01

    Quadratic electro-optic effects (QEOEs) and electro-absorption (EA) process in a GaN/AlGaN spherical quantum dot are theoretically investigated. It is found that the magnitude and resonant position of third-order nonlinear optical susceptibility depend on the nanostructure size and aluminum mole fraction. With increase of the well width and barrier potential, quadratic electro-optic effect and electro-absorption process nonlinear susceptibilities are decreased and blueshifted. The results sho...

  5. Investigation of TiO2 Thin Film Growth by Layer-by-Layer Self-Assembly for Application to Optical Devices

    Science.gov (United States)

    Kyung, Kyu-Hong; Fujimoto, Kouji; Shiratori, Seimei; Kim, Jin-Ho; Kim, Sae-Hoon

    2010-04-01

    Recently, optical thin films fabricated using a water-based process have been strongly demanded. We fabricated TiO2 thin films consisting of poly(diallyl dimethyl ammonium chloride) (PDDA) and titanium(IV) bis(ammonium lactate) dihydroxide (TALH) for optical devices fabricated using layer-by-layer self-assembly. We report the effects of the pH and concentration of a solution, immersion time, and the amount of NaCl added to a solution on the thickness, morphology, surface roughness, and transmittance of fabricated thin films. The thickness, surface morphology, and transparency of (PDDA/TALH) thin films were determined by ellipsometry, field-emission scanning microscopy (FE-SEM), atomic force microscopy (AFM), and ultraviolet-visible (UV-vis) spectrometry. It was found that the thickness and surface morphology of (PDDA/TALH) multilayer films can be controlled by adjusting the TiO2 particle size of TALH solution. TiO2 particle size was controlled by adjusting the pH of TALH solution and the concentration of PDDA solution, and by adding NaCl to PDDA solution. It was found that we can increase deposition speed while maintaining optical quality by suppressing the surface roughness within 10 nm. These experimental results showed that the fabrication speed of thin films can be markedly increased, by approximately 6-fold.

  6. An investigation on a novel PDLC film's fabrication and its electro-optical properties

    Institute of Scientific and Technical Information of China (English)

    DING HongLiu; ZHAO Ting; CHENG YuXiao; PANG YueHong; XU He; SHI GuoYue; JIN LiTong

    2007-01-01

    A polymer dispersed liquid crystal (PDLC) film that has good electro-optical properties is produced by the method of polymerized-induced phase separation. Based on the application foreground, its capability parameters, such as contrast ratio, work voltage, and visual angle, are characterized for the first time by a white light but not a fixed wavelength light. The results show the PDLC film has a low work-voltage of 20 V, more than 150° visual angle, high stability, and long lifetime. The differences between plastic and glass ITO-coated substrates of PDLC films are also studied in this paper. The plastic substrate has better property and will have a wider perspective especially in the portable, tender and folded display devices. Due to adjustable properties of film by electric field, PDLC has the potential application for display device, sensor, switch, grating, and new generation analytical apparatus.

  7. An investigation on a novel PDLC film’s fabrication and its electro-optical properties

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A polymer dispersed liquid crystal (PDLC) film that has good electro-optical properties is produced by the method of polymerized-induced phase separation. Based on the application foreground, its capability parameters, such as contrast ratio, work voltage, and visual angle, are characterized for the first time by a white light but not a fixed wavelength light. The results show the PDLC film has a low work-voltage of 20 V, more than 150° visual angle, high stability, and long lifetime. The differences between plastic and glass ITO-coated substrates of PDLC films are also studied in this paper. The plastic substrate has better property and will have a wider perspective especially in the portable, tender and folded display devices. Due to adjustable properties of film by electric field, PDLC has the potential application for display device, sensor, switch, grating, and new generation analytical apparatus.

  8. Investigation of aquifer-estuary interaction using wavelet analysis of fiber-optic temperature data

    Science.gov (United States)

    Henderson, R.D.; Day-Lewis, F. D.; Harvey, C.F.

    2009-01-01

    Fiber-optic distributed temperature sensing (FODTS) provides sub-minute temporal and meter-scale spatial resolution over kilometer-long cables. Compared to conventional thermistor or thermocouple-based technologies, which measure temperature at discrete (and commonly sparse) locations, FODTS offers nearly continuous spatial coverage, thus providing hydrologie information at spatiotemporal scales previously impossible. Large and information-rich FODTS datasets, however, pose challenges for data exploration and analysis. To date, FODTS analyses have focused on time-series variance as the means to discriminate between hydrologic phenomena. Here, we demonstrate the continuous wavelet transform (CWT) and cross-wavelet transform (XWT) to analyze FODTS in the context of related hydrologic time series. We apply the CWT and XWT to data from Waquoit Bay, Massachusetts to identify the location and timing of tidal pumping of submarine groundwater Copyright 2009 by the American Geophysical Union.

  9. Investigation of optical metastability in GaN using photoluminescence spectroscopy

    International Nuclear Information System (INIS)

    We report photo-induced changes of optically active defects in GaN under 325 nm excitation. Cooling the sample in the dark and then performing rapid measurements using a Fourier transform spectrometer allows the changes in the spectrum to be followed on time scales of minutes. At first, the characteristic blue and yellow luminescence bands are observed, with the blue band roughly four times stronger than the yellow. Upon continuous irradiation the yellow band increases rapidly at first, and then more slowly to become the dominant band after approximately 60 min. During this time the blue band decreases. The temperature dependence of this fatigue behaviour is reported for both constant and intermittent illumination

  10. An optical coherence tomography investigation of materials defects in ceramic fixed partial dental prostheses

    Science.gov (United States)

    Sinescu, Cosmin; Negrutiu, Meda; Hughes, Michael; Bradu, Adrian; Todea, Carmen; Rominu, Mihai; Laissue, Philippe L.; Podoleanu, Adrian Gh.

    2008-04-01

    Metal ceramic and integral ceramic fixed partial prostheses are mainly used in the frontal part of the dental arch because for esthetics reasons. The masticatory stress may induce fractures of the bridges. There are several factors that are associated with the stress state created in ceramic restorations, including: thickness of ceramic layers, mechanical properties of the materials, elastic modulus of the supporting substrate material, direction, magnitude and frequency of applied load, size and location of occlusal contact areas, residual stresses induced by processing or pores, restoration-cement interfacial defects and environmental defects. The fractures of these bridges lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. The purpose of this study is to evaluate the capability of optical coherence tomography (OCT) in detection and analysis of possible material defects in metal-ceramic and integral ceramic fixed partial dentures.

  11. Investigation of nonlinear optical properties of various organic materials by the Z-scan method

    Science.gov (United States)

    Ganeev, R. A.; Boltaev, G. S.; Tugushev, R. I.; Usmanov, T.

    2012-06-01

    We have studied the nonlinear optical properties of various organic materials (vegetable oil, juice, wine, cognac, Coca-Cola and Fanta drinks, Nescafé coffee, tea, gasoline, clock oil, glycerol, and polyphenyl ether) that are used in everyday life. Their nonlinearities have been studied by the Z-scan method in the near-IR and visible spectral ranges. We have shown that the majority of samples possess a nonlinear absorption; however, some of the studied materials show a strong saturated absorption and nonlinear refraction. Red wine and glycerol proved to be the most interesting materials. For these samples, we have observed a change in the sign of the nonlinear absorption with increasing laser intensity, which was attributed to the competition between two-photon absorption and saturated absorption.

  12. NMR Investigation of Optical Polarization of Nuclear Spins in GaAs

    Science.gov (United States)

    Paravastu, Anant; Hayes, Sophia; Schwickert, Birgit; Reimer, Jeffrey; Dinh, Long; Balooch, Mehdi

    2003-03-01

    Light-induced nuclear spin alignments have been measured in GaAs as a function of photon energy, irradiation time, and sample temperature using NMR spectroscopy at 9.4 Tesla and 10 to 50 K. Significant optical enhancements were observed at a range of photon energies, starting just below the band gap and persisting through 100 meV above the gap. Irradiation above the band gap resulted in thermally activated NMR signal enhancements while sub band gap irradiation did not. Short and long irradiation time dependencies revealed insights into the nature of cross relaxation between electronic nuclear spins, contradicting mechanisms based on either localized electron-nuclear contact at defect sites or cross relaxation between nuclei and free electrons. We propose that the presence of a mobile or delocalized enabling electronic species characterized by a long electron-nuclear correlation time, such as an exciton, is necessary in any mechanism which explains the data.

  13. Synthesis and investigation of optical properties of ZnS nanostructures

    Indian Academy of Sciences (India)

    Neslihan Üzar; M Çetin Arikan

    2011-04-01

    Structural characterizations of wurtzite zinc sulfide (ZnS) nanostructures synthesized by vapour–liquid–solid technique (VLS) were carried out by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analyses. Spectral dependence of photoluminescence (PL) was also carried out for optical characterization. PL results indicate that the bandgap energy of bulk ZnS which is 3.68 eV at room temperature changes from 3.7 eV to 3.72 eV depending on the size of the structures. We also supported these results by calculating the bandgap energies theoretically with using the infinite potential well approximation for 1D structures.

  14. Investigation of the thermo-optic effect in doubly coupled photonic crystal split-beam nanocavities

    Science.gov (United States)

    Lin, Tong; Tao, Jifang; Chau, Fook Siong; Deng, Jie; Zhou, Guangya; Gu, Yuandong

    2016-07-01

    We design and experimentally demonstrate doubly coupled photonic crystal split-beam nanocavities. The thermal response of the coupled nanocavities is characterized by controlling the device temperature: the resonant wavelengths of the odd mode (1557.28 nm) and even mode (1567.18 nm) are both redshifted linearly from 17.4 °C to 46.5 °C. The tuning ratio of the two modes is measured to be 97.4%, implying that they respond almost the same to temperature changes. Therefore, changes of the wavelength difference between this pair of modes can be applied to effectively decouple the thermo-optic effect from the optomechanical effect without on-chip temperature self-referencing. Additionally, the topmost quality-factor approaches 28 300 throughout the thermal tuning. The proposed structure paves the way for studying purely optomechanical actuations.

  15. An Investigation into the Effect of Hydrodynamic Cavitation on Diesel using Optical Extinction

    Science.gov (United States)

    Lockett, R. D.; Fatmi, Z.; Kuti, O.; Price, R.

    2015-12-01

    A conventional diesel and paraffinic-rich model diesel fuel were subjected to sustained cavitation in a custom-built high-pressure recirculation flow rig. Changes to the spectral extinction coefficient at 405 nm were measured using a simple optical arrangement. The spectral extinction coefficient at 405 nm for the conventional diesel sample was observed to increase to a maximum value and then asymptotically decrease to a steady-state value, while that for the paraffinic-rich model diesel was observed to progressively decrease. It is suggested that this is caused by the sonochemical pyrolysis of mono-aromatics to form primary soot-like carbonaceous particles, which then coagulate to form larger particles, which are then trapped by the filter, leading to a steady-state spectral absorbance.

  16. Mechanism of termination of bacteriophage DNA packaging investigated with optical tweezers

    Science.gov (United States)

    delToro, Damian J.; Smith, Douglas E.

    2012-10-01

    The genomes of many dsDNA viruses are replicated by a mechanism that produces a long concatemer of multiple genomes. These viruses utilize multifunctional molecular motor complexes referred to as "terminases" that can excise a unit genome length of DNA and package it into preformed viral shells. Remarkably, the terminase motor can initiate packaging at the appropriate start point, translocate DNA, sense when a sufficient length has been packaged, and then switch into a mode where it arrests and cleaves the DNA to release a filled virus particle. We have recently developed an improved method to measure single phage lambda DNA packaging using dual-trap optical tweezers and pre-stalled motor-DNA-procapsid complexes. We are applying this method to test proposed mechanisms for the sensor that triggers termination; specifically a velocity-monitor model vs. energy-monitor model vs. capsid-filling monitor model.

  17. Preliminary investigations toward nighttime aerosol optical depth retrievals from the VIIRS Day/Night Band

    Directory of Open Access Journals (Sweden)

    R. S. Johnson

    2013-05-01

    Full Text Available A great need exists for reliable nighttime aerosol products at high spatial and temporal resolution. In this concept demonstration study, using Visible/Infrared Imager/Radiometer Suite (VIIRS Day/Night Band (DNB observations on the Suomi National Polar-orbiting Partnership (NPP satellite, a new method is proposed for retrieving nighttime aerosol optical depth (τ using the contrast between regions with and without artificial surface lights. Evaluation of the retrieved τ values against daytime AERONET data from before and after the overpass of the VIIRS satellite over the Cape Verde, Grand Forks, and Alta Floresta AERONET stations yields a coefficient of determination (r2 of 0.71. This study suggests that the VIIRS DNB has the potential to provide useful nighttime aerosol detection and property retrievals.

  18. Preliminary investigations toward nighttime aerosol optical depth retrievals from the VIIRS day/night band

    Directory of Open Access Journals (Sweden)

    R. S. Johnson

    2013-01-01

    Full Text Available A great need exists for reliable nighttime aerosol products at high spatial and temporal resolution. In this concept demonstration study, using Visible/Infrared Imager/Radiometer Suite (VIIRS Day/Night Band (DNB observations on the Suomi National Polar-orbiting Partnership (NPP satellite, a new method is proposed for retrieving nighttime aerosol optical depth (τ using the contrast between regions with and without artificial surface lights. Evaluation of the retrieved τ values against daytime AERONET data from before and after the overpass of the VIIRS satellite over the Cape Verde, Grand Forks, and Alta Floresta AERONET stations yields a coefficient of determination (r2 of 0.71. This study suggests that the VIIRS DNB has the potential to provide useful nighttime aerosol detection and property retrievals.

  19. An investigation on the magneto-optic properties of terbium gallium garnet under high magnetic field

    International Nuclear Information System (INIS)

    The superexchange interaction on a magnetic ion may be represented by an effective field Hm = λM in some paramagnetic materials, here λ is the coefficient of effective field and M = χHe with χ being the magnetic susceptibility and He being the applied field. The variation of the equivalent λχ with the dynamic applied field is given and the crystal field-splitting levels of the excited configuration 4f75d1 of the Tb3+ ion are calculated in the Tb3Ga5O12. By means of the effective field Hm and the applied field He, the Faraday rotation of Tb3Ga5O12 at 6 K and 41 K, under the high magnetic field and at 0.63 μm wavelength, are presented. Our calculated results are in agreement with the experimental data. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  20. Investigation of Third Order Optical Nonlinearity and Reverse Saturable Absorption of Octa-alkoxy Metallophthalocyanines

    Science.gov (United States)

    Sanghadasa, Mohan; Shin, In-Seek; Barr, Thomas A.; Clark, Ronald D.; Guo, Huai-Song; Martinez, Angela; Penn, Benjamin G.

    1998-01-01

    In recent years, there has been a growing interest in the development of passive optical power limiters for the protection of the human eye and solid-state sensors from damage caused by energetic light pulses and also for other switching applications. One of the key issues involved is the search for appropriate materials that show effective reverse saturable absorption. Phthalocyanines seem to be good candidates for such applications because of their higher third order nonlinearity and the unique electronic absorption characteristics. A series of 1,4,8,11,15, 18,22,25-octa-alkoxy metallophthalocyanines containing various central metal atoms such as zinc, copper, palladium, cobalt and nickel were characterized for their third order nonlinearity and for their nonlinear absorptive properties to evaluate their suitability to function as reverse saturable absorbers.

  1. Investigation of Spectral Characteristics for Microstructured Quasi-Optical Bandpass Subteraherz Filters

    Science.gov (United States)

    Kuznetsov, S. A.; Gelfand, A. V.

    2016-03-01

    The electrodynamic features of quasi-optical bandpass filters based on multilayer microstructured frequency selective surfaces intended for effective spectral selection of subteraherz electromagnetic radiation are considered. As an optimal solution, the multiplex filters are highlighted wherein tripole-slot self-bearing copper microstructures free from dielectric substrates are employed. The results of the experimental development for such filters are presented by the example of structures with resonant transmission at the frequencies of 0.6 and 1 THz, and the details of testing their spectral performance in the range of 0.1-1.5 THz using a BWO spectroscopy technique are described. Good agreement between the experimental data and the results of theoretical predictions is demonstrated.

  2. An investigation of the influence of reconceptualization of demonstrative experimental activities of optics in high school

    Directory of Open Access Journals (Sweden)

    Jair Lúcio Prados Ribeiro

    2013-08-01

    Full Text Available In this work, we analyze the influence that the use of demonstrative experiments can bring to the learning of optics. It is assumed that the development of experimental activities, when reconceptualized according to Hodson proposal, tends to contribute to the generation of cognitive conflicts when compared to traditional didactic experience. Justifications are given for an analysis of changes under a Piagetian bias, reconciled with Hodson proposal. The methodology used to structure the topics presentations was quasi-experimental, contrasting an experimental group with a control group. The measuring of the effectiveness of the suggested working method was made from a quantitative analysis, which identified some of the topics discussed had better results in learning, being more tied to the experiments carried out.

  3. Simulation of Cl- secretion in epithelial tissues: New methodology estimating activity of electro-neutral Cl- transporter

    Directory of Open Access Journals (Sweden)

    Kouhei eSasamoto

    2015-12-01

    Full Text Available Transcellular Cl- secretion is, in general, mediated by two steps; 1 the entry step of Cl- into the cytosolic space from the basolateral space across the basolateral membrane by Cl- transporters, such as Na+-K+-2Cl- cotransporter (NKCC1, an isoform of NKCC, and 2 the releasing step of Cl- from the cytosolic space into the luminal (air space across the apical membrane via Cl- channels, such as cystic fibrosis transmembrane conductance regulator (CFTR Cl- channel. Transcellular Cl- secretion has been characterized by using various experimental techniques. For example, measurements of short-circuit currents in the Ussing chamber and patch clamp techniques provide us information on transepithelial ion movements via transcellular pathway, transepithelial conductance, activity (open probability of single channel, and whole cell currents. Although many investigators have tried to clarify roles of Cl- channels and transporters located at the apical and basolateral membranes in transcellular Cl- secretion, it is still unclear how Cl- channels/transporters contribute to transcellular Cl- secretion and are regulated by various stimuli such as Ca2+ and cAMP. In the present study, we simulate transcellular Cl- secretion using mathematical models combined with electrophysiological measurements, providing information on contribution of Cl- channels/transporters to transcellular Cl- secretion, activity of electro-neutral ion transporters and how Cl- channels/transporters are regulated.

  4. Structural, electronic and optical properties of Li intercalated on MO3 (M: Mo, W): A first principle investigation

    Science.gov (United States)

    Mahmoudi, A.; Faraoun, H. I.; Benabadji, M. K.; Abdellaoui, I.; Dergal, M.

    2016-03-01

    The correlations between electronic and optical properties of pure MO3 (M=Mo, W) and the effect of Li intercalated in the matrix are investigated within density functional theory using both the revised gradient-corrected Perdew-Burke-Ernzerhof (GGA-PBE), GGA+U and HSE06 functional frameworks along with ab initio pseudopotentials method. Calculation performed with HSE06 functional proves that all these compounds are wide band gap semiconductors. The energy gap value is found to decrease with lithium incorporation, affecting the visible absorption coefficients.

  5. Investigation of optical and interfacial properties of Ag/Ta{sub 2}O{sub 5} metal dielectric multilayer structure

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, P., E-mail: piyali.sarkar4@gmail.com; Jena, S.; Tokas, R. B.; Thakur, S.; Sahoo, N. K. [Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Rao, K. D.; Misal, J. S.; Prathap, C. [Optics and Thin Film Laboratory, BARC-Vizag, Autonagar, Visakhapatnam-530012 (India)

    2015-06-24

    One-dimensional periodic metal-dielectric multilayer thin film structures consisting of Ag and Ta{sub 2}O{sub 5} alternating layers are deposited on glass substrate using RF magnetron sputtering technique. The spectral property of the multilayers has been investigated using spectrophotometry technique. The optical parameters such as refractive index, extinction coefficient, band gap etc., along with film thickness as well as the interfacial layer properties which influence these properties have been probed with spectroscopic ellipsometry technique. Atomic force microscopy has been employed to characterize morphological properties of this metal-dielectric multilayer.

  6. Investigation on the effect of beam divergence angle upon output waveform based on stimulated Brillouin scattering optical limiting

    Institute of Scientific and Technical Information of China (English)

    Hasi Wu-Li-Ji; Lu Huan-Huan; Gong Sheng; Fu Mei-Ling; Lin Zhi-Wei; Lin Dian-Yang; He Wei-Ming

    2009-01-01

    This paper investigates the effect of beam divergence angle on output waveform based on stimulated Brillouin scattering optical limiting. Output waveforms in the case of different pump divergence angles are numerically simulated,and validated in a Nd:YAG seed-injected laser system. The results indicate that a small pump divergence angle can lead to good interaction between pump and Stokes, and a platform can be easily realized in the transmitted waveform.In contrast, a peak followed by the platform appears when the divergence angle becomes large.

  7. Investigation of optical and interfacial properties of Ag/Ta2O5 metal dielectric multilayer structure

    International Nuclear Information System (INIS)

    One-dimensional periodic metal-dielectric multilayer thin film structures consisting of Ag and Ta2O5 alternating layers are deposited on glass substrate using RF magnetron sputtering technique. The spectral property of the multilayers has been investigated using spectrophotometry technique. The optical parameters such as refractive index, extinction coefficient, band gap etc., along with film thickness as well as the interfacial layer properties which influence these properties have been probed with spectroscopic ellipsometry technique. Atomic force microscopy has been employed to characterize morphological properties of this metal-dielectric multilayer

  8. Investigation of noise in Lightwave Synthesized Frequency Sweeper seeded LIDAR anemometers from leakage through the Acousto Optic Modulators

    DEFF Research Database (Denmark)

    Pedersen, Anders Tegtmeier; Lindelöw, Per Jonas Petter

    2009-01-01

    Train (FSPT) modulated lidars the leakage will give rise to rapidly growing noise in the bins which corresponds to the signal from low radial wind velocities. It is likely that noise canceling techniques similar to those used for RIN removal has to be deployed for measurements of low wind velocities.......Lightwave Synthesized Frequency Sweepers (LSFS) have potential use as lightsources in lidar anemometers. In this paper noise due to leakage in the acousto optic modulators in an LSFS is investigated. Theoretical expressions describing the build-up of noise in the LSFS due to leakage are derived...

  9. Dominant shallow donors in zinc oxide layers obtained by low-temperature atomic layer deposition: Electrical and optical investigations

    International Nuclear Information System (INIS)

    This work is focused on the electrical and optical analyses used to estimate the activation energy of the dominant shallow donor in thin ZnO films obtained at low temperature by the atomic layer deposition process. These two approaches, based on the temperature-dependent classical Hall effect and photoluminescence investigations, yielded a donor activation energy ED in the range of 30–40 meV, including the estimated error margins. This value, as confirmed by layer composition studies, is attributed to the presence of zinc atoms in the interstitial positions of the ZnO lattice

  10. An optical and structural investigation into CdTe nanocrystals embedded into the tellurium lithium borophosphate glass matrix

    Institute of Scientific and Technical Information of China (English)

    WAGEH; S

    2010-01-01

    Cadmium telluride nanocrystals that form in the TeO2-Li2O-B2O3-P2O5 glass matrix have been synthesized and studied.They are investigated by X-ray diffraction(XRD),optical transmission and infrared spectroscopy.It has been shown that the long annealing time effect on present samples leads to the growth of CdTe nanoparticles and an increase of tellurium oxide on the surface of nanocrystallites.On the other hand,the infrared spectroscopy shows that the phosphate and borate networks of the glass matrices are modified with doping by CdTe nanoparticles.

  11. Investigation of optical, structural and morphological properties of nanostructured boron doped TiO2 thin films

    Indian Academy of Sciences (India)

    Savaş Sönmezoǧlu; Banu Erdoǧan; İskender Askeroǧlu

    2013-12-01

    Pure and different ratios (1, 3, 5, 7 and 10%) of boron doped TiO2 thin films were grown on the glass substrate by using sol–gel dip coating method having some benefits such as basic and easy applicability compared to other thin film production methods. To investigate the effect of boron doped on the physical properties of TiO2, structural, morphological and optical properties of growth thin films were examined. 1% boron-doping has no effect on optical properties of TiO2 thin film; however, optical properties vary with > 1%. From X-ray diffraction spectra, it is seen that TiO2 thin films together with doping of boron were formed along with TiB2 hexagonal structure having (111) orientation, B2O3 cubic structure having (310) orientation, TiB0.024O2 tetragonal structure having rutile phase (110) orientation and polycrystalline structures. From SEM images, it is seen that particles together with doping of boron have homogeneously distributed and held onto surface.

  12. Investigation of optical limiting properties of Aluminium nanoparticles prepared by pulsed laser ablation in different carrier media

    International Nuclear Information System (INIS)

    In this communication, we carried out the systematic investigation of nonlinear absorption and scattering properties of Aluminium nanoparticles (Al NPs) in various polar and non-polar solvents. Al NPs were synthesized with pulsed Nd:YAG laser operated at 1064 nm by ablating Al target in polar and non-polar liquid environment like chloroform, chlorobenzene, toluene, benzene, and carbon tetrachloride. Synthesized Al NPs colloids of various solvents differ in appearance and UV-Vis extinction spectra exhibit absorption in the UV region. The characterization of Al NPs performed by Transmission electron microscopy (TEM) studies reveal that NPs are made up of a well crystallized Al inner part (bright zone) embedded with an amorphous metal Al shell (dark region). Growth, aggregation, and precipitation mechanisms which influence the optical properties and stability of NPs are found to be related to the dipole moment of the surrounding liquid environment. The nonlinear absorption and scattering studies are performed by open aperture Z-scan technique with 532 nm under nanosecond pulse excitation. The Z-scan measurements are fitted theoretically to estimate both two-photon absorption (TPA) and nonlinear scattering (NLS) coefficients. In polar solvents like chlorobenzene, chloroform synthesized Al NPs exhibited higher TPA, NLS coefficient values, and lower optical limiting threshold values in comparison with partially polar solvent like toluene and non-polar solvents like benzene and carbontetrachloride. These results indicate the potential use of Al NPs as a versatile optical limiting material

  13. 75 FR 6862 - Airworthiness Directives; Bombardier, Inc. Model CL-600-1A11 (CL-600), CL-600-2A12 (CL-601), CL...

    Science.gov (United States)

    2010-02-12

    ... Policies and Procedures (44 FR 11034, February 26, 1979); and 3. Will not have a significant economic.... Model CL-600-1A11 (CL- 600), CL-600-2A12 (CL-601), CL-600-2B16 (CL-601-3A, CL-601-3R, and CL- 604 Variants (Including CL-605 Marketing Variant)) Airplanes AGENCY: Federal Aviation Administration (FAA),...

  14. Validation of a Hybrid Microwave-Optical Monitor to Investigate Thermal Provocation in the Microvasculature.

    Science.gov (United States)

    Al-Armaghany, Allann; Tong, Kenneth; Highton, David; Leung, Terence S

    2016-01-01

    We have previously developed a hybrid microwave-optical system to monitor microvascular changes in response to thermal provocation in muscle. The hybrid probe is capable of inducing deep heat from the skin surface using mild microwaves (1-3 W) and raises the tissue temperature by a few degrees Celsius. This causes vasodilation and the subsequent increase in blood volume is detected by the hybrid probe using near infrared spectroscopy. The hybrid probe is also equipped with a skin cooling system which lowers the skin temperature while allowing microwaves to warm up deeper tissues. The hybrid system can be used to assess the condition of the vasculature in response to thermal stimulation. In this validation study, thermal imaging has been used to assess the temperature distribution on the surface of phantoms and human calf, following microwave warming. The results show that the hybrid system is capable of changing the skin temperature with a combination of microwave warming and skin cooling. It can also detect thermal responses in terms of changes of oxy/deoxy-hemoglobin concentrations. PMID:26782243

  15. Investigation of proton damage in III-V semiconductors by optical spectroscopy

    Science.gov (United States)

    Yaccuzzi, E.; Khachadorian, S.; Suárez, S.; Reinoso, M.; Goñi, A. R.; Strittmatter, A.; Hoffmann, A.; Giudici, P.

    2016-06-01

    We studied the damage produced by 2 MeV proton radiation on epitaxially grown InGaP/GaAs structure by means of spatially resolved Raman and photoluminescence (PL) spectroscopy. The irradiation was performed parallel to the sample surface in order to determine the proton penetration range in both compounds. An increase in the intensity of longitudinal optical phonons and a decrease in the luminescence were observed. We associate these changes with the creation of defects in the damaged region, also responsible for the observed change of the carrier concentration in the GaAs layer, determined by the shift of the phonon-plasmon coupled mode frequency. From the spatially resolved profile of the PL and phonon intensities, we obtained the proton range in both materials and we compared them with stopping and range of ions in matter simulations. The comparison between the experimentally obtained proton range and simulations shows a very good agreement for GaAs but a discrepancy of 20% for InGaP. This discrepancy can be explained in terms of limitations of the model to simulate the electronic orbitals and bonding structure of the simulated compound. In order to overcome this limitation, we propose an increase in 40% in the electronic stopping power for InGaP.

  16. Investigating in vivo airway wall mechanics during tidal breathing with optical coherence tomography

    Science.gov (United States)

    Robertson, Claire; Lee, Sang-Won; Ahn, Yeh-Chan; Mahon, Sari; Chen, Zhongping; Brenner, Matthew; George, Steven C.

    2011-10-01

    Optical coherence tomography (OCT) is a nondestructive imaging technique offering high temporal and spatial resolution, which makes it a natural choice for assessing tissue mechanical properties. We have developed methods to mechanically analyze the compliance of the rabbit trachea in vivo using tissue deformations induced by tidal breathing, offering a unique tool to assess the behavior of the airways during their normal function. Four-hundred images were acquired during tidal breathing with a custom-built endoscopic OCT system. The surface of the tissue was extracted from a set of these images via image processing algorithms, filtered with a bandpass filter set at respiration frequency to remove cardiac and probe motion, and compared to ventilatory pressure to calculate wall compliance. These algorithms were tested on elastic phantoms to establish reliability and reproducibility. The mean tracheal wall compliance (in five animals) was 1.3+/-0.3×10-5 (mm Pa)-1. Unlike previous work evaluating airway mechanics, this new method is applicable in vivo, noncontact, and loads the trachea in a physiological manner. The technique may have applications in assessing airway mechanics in diseases such as asthma that are characterized by significant airway remodeling.

  17. An investigation of the magneto-optical properties of thin-film magnetic structures

    Science.gov (United States)

    Tsidaeva, N. I.; Abaeva, V. V.; Enaldieva, E. V.; Magkoev, T. T.; Turiev, A. M.; Ramonova, A. G.; Butkhuzi, T. T.; Tvauri, I.

    2013-11-01

    This study reports on the performance of multilayer film structures, which are a very prospective material for thin-film magnetic sensors. The magnetic and magneto-optical properties of iron and cobalt thin films and also ferromagnetic (FM)/non-magnetic layer (NML)/FM trilayers, prepared using a magnetron sputtering system, are presented. The FM layer thickness of tFe and tCo in trilayers varied from 25 to 100 Å and the NML thickness of tNML varied from 5 to 2000 Å. In the NML/FM samples, the NML thickness varied from 0 to 400 Å. The dependences of the hysteresis characteristics of Fe films on the NML thickness were found. The dependence of the transverse Kerr effect (TKE) magnitude on tFe was established. It was shown experimentally that TKE is sensitive to the magnetization up to a certain depth range below the surface of ferromagnetic—the information depth. It was discovered that the in-plane hysteresis characteristic of the trilayers is strongly dependent on tnml. So existence of the exchange coupling between FM layers through NML and its oscillatory behaviour (from antiferromagnetic (AF) to ferromagnetic (F) order) were experimentally established. It was found that the period AF-F-AF oscillations of exchange coupling is equal to 5-10 Å.

  18. Vortex motion in granular MgB2 thin films - investigations with magneto-optical imaging

    International Nuclear Information System (INIS)

    In magnesium diboride (MgB2) thin films there are different kinds of vortex motion. Flux flow and thermally activated flux creep form the current carrying state in an external magnetic field. At lower temperatures dynamically driven flux avalanches containing areas of vanishing supercurrents occur. Flux penetration as well as the critical current density can be determined locally and quantitatively via magneto-optical imaging based on the Faraday effect. We use this method to measure properties of MgB2 films with different granularity. In a particular production process we achieved to create areas of varying granularity on an individual substrate. This allows a direct analysis of the consequences of granularity. It is shown that in granular films the dendritic state as well as the regular critical state both are modified: we find a reduced critical current density jc, which decreases rapidly with increasing temperature. Additionally magnetic avalanches are favoured in the granular area, whereas generally they are triggered by high current densities. This requires a more detailed understanding of formation and propagation of magnetic avalanches in inhomogeneous media.

  19. Investigation of the optical fields of flat-spectrum radio sources to faint limiting magnitudes

    International Nuclear Information System (INIS)

    A deep optical survey of the fields of 16 flat-spectrum radio sources has been carried out using the Hale 5-m telescope, with a prototype charge-coupled device as a detector. These sources are members of a complete sample, selected as having S(2.7 GHz) > 1.5 Jy, and were either unidentified, or were identified with very faint objects on the prints of the Palomar Sky Survey. Identifications are found for 12 of these objects; six are galaxies and six are stellar objects. Identifications for the 2.7-GHz sample are therefore now 96 per cent complete, allowing much improved redshift distributions to be derived. Values of V/Vsub(max) for the sample members have also been calculated, with the result that for the flat-spectrum quasars is 0.68, rather than the values nearer 0.5 derived from studies of deeper samples. This result indicates that both the steep-spectrum and flat-spectrum quasars undergo similar degrees of cosmological evolution. (author)

  20. Investigation of an Intelligent System for Fiber Optic-Based Epidural Anesthesia

    Directory of Open Access Journals (Sweden)

    Cihun-Siyong Alex Gong

    2014-01-01

    Full Text Available Even though there have been many approaches to assist the anesthesiologists in performing regional anesthesia, none of the prior arts may be said as an unrestricted technique. The lack of a design that is with sufficient sensitivity to the targets of interest and automatic indication of needle placement makes it difficult to all-round implementation of field usage of objectiveness. In addition, light-weight easy-to-use realization is the key point of portability. This paper reports on an intelligent system of epidural space identification using optical technique, with particular emphasis on efficiency-enhanced aspects. Statistical algorithms, implemented in a dedicated field-programmable hardware platform along with an on-platform application-specific integrated chip, used to advance real-time self decision making in needle advancement are discussed together with the feedback results. Clinicians' viewpoint of improving the correct rate of our technique is explained in detail. Our study demonstrates not only that the improved system is able to behave as if it is a skillful anesthesiologist but also it has potential to bring promising assist into clinical use under varied conditions and small amount of sample, provided that several concerns are addressed.

  1. The investigation and prospect on optical principles of multiple space laser communication

    Science.gov (United States)

    Zhang, Yalin; An, Yan; Jiang, Huilin; Jiang, Lun; Wang, Chao; Zhan, Juntong; Han, Long

    2015-10-01

    Multiple laser communication is the key point of integrated space-ground network system, and it is the necessary prerequisite of realizing the network communication link between multiple satellites. In this paper, current situation and the development status of multiple laser communication are introduced, then optical principles and methods of multiple laser communication are discussed, and advantages and disadvantages are compared and analyzed with different multiple space laser communication system. The systems were classified according to different principles, including the simple principle type, exchange points type, RF and laser combined type, field expanding type and large field communication type. Then we look into the future of multiple laser communication systems, and the result shows that the paraboloid of revolution type has great potential in the future's laser communication space network ,for it's large communication range and high energy efficiency. It can be used to communicate between the aircraft platform, airship platforms and satellite platforms. Which laid the foundation for the future development of the laser communication space network.

  2. Structural, morphological, optical and photocatalytic investigation of Ag-doped TiO2

    Science.gov (United States)

    Kundu, Virender Singh; Singh, Davender; Maan, A. S.; Tanwar, Amit

    2016-05-01

    The pure and Ag-doped TiO2 nanoparticles were prepared by using Titanium isoproxide (TTIP), silver nitrate sodium hydroxide and sodium hydroxide. The calcined nanoparticles at 400°C were characterized by means of X-ray diffraction (XRD). XRD analyses reveal that the nanoparticles of various doping concentration were having anatase phase. The particle size was calculated by Scherrer formula and was found 11.08 nm for pure TiO2 and 8.86 nm for 6 mol % Ag doped TiO2. The morphology and nature of nanoparticles was analyzed by using scanning electron microscope (SEM), the optical absorption spectra of pure TiO2 and Ag-doped TiO2 nanoparticles showed that absorption edge increases towards longer wavelength from 390 nm (pure) to 450 nm (doped), also band gap energy calculated from Tauc's plot decrease from 3.20eV to 2.92eV with increase in doing. The measurement of photocatalytic properties of pure TiO2 and Ag-doped TiO2 nanoparticles showed that Ag-doped TiO2 degrades MB dye more efficiently than pure TiO2.

  3. Aerosol Optical Depth investigated with satellite remote sensing observations in China

    International Nuclear Information System (INIS)

    In this study, Aerosol Optical Depth (AOD) at 550nm from the MODIS sensor on board the Terra/Aqua satellites were compared with sun photometer (CE-318) measurements from 11 AERONET stations in China. The average correlation coefficient (R) value from the AOD product, using the Aqua-MODIS Deep Blue algorithm, in the Hexi Corridor was 0.67. The MODIS Dark Target algorithm AOD product is superior to Deep Blue algorithm AOD products in SACOL of the Semi-arid regions of the Loess Plateau. These two kinds of algorithm are not applicable to sites in Lanzhou city. The average R value of Dark Target algorithm AOD MODIS products is 0.91 for Terra and 0.88 for Aqua in the eastern part of China. According to the analysis of spatial and temporal characteristics of the two MODIS AOD products in China, high value areas are mainly distributed in the southern part of Xinjiang (0.5∼0.8), Sichuan Basin (0.8∼0.9), North China (0.6∼0.8) and the middle and lower reaches of the Changjiang River (0.8∼1.0). The Deep Blue algorithm for Aqua-MODIS is a good supplement for the retrieval of AOD above bright surfaces of deserts in Northwest China

  4. Magneto-optical investigation of relaxation of spatial distribution of HTSC-strip magnetic field after switching on transport current

    International Nuclear Information System (INIS)

    For the first time the efficiency of using the magneto-optical technique has been demonstrated for the investigation of the spatial-time relaxation of the magnetic field of YBa2Cu3O7 strip after switching on the transport current. It has been shown that the evolution of the magnetic flux distribution is well described in the framework of the modified Bean model with the time-depending critical current within 50 ms after current switching on the critical current magnitude decreases by ∼ 15%. In such manner the importance of the thermo-induced motion of magnetic flux is proved for the investigated mode. The evaluated value of the energy of magnetic vortices pinning U0 ≅ 20 kT

  5. Investigation on the Optical and Surface Morphology of Conjugated Polymer MEH-PPV:ZnO Nanocomposite Thin Films

    Directory of Open Access Journals (Sweden)

    Nurul Zayana Yahya

    2012-01-01

    Full Text Available Thin films of red color poly(2-methoxy-5(2′-ethylhexyloxy-phenylene vinylene (MEH-PPV containing different weight percent of ZnO nanoparticles were obtained by spin-coating techniques. The MEH-PPV:ZnO solutions were spin coated onto silicon and glass substrates. The spun MEH-PPV:ZnO thin films were then used to investigate optical properties by using ultraviolet-visible spectrometer (UV-Vis and photoluminescence spectrophotometer (PL. The morphologies were investigated by using field emission scanning electron microscopy (FESEM, while the identification of ZnO in the final product was determined by using energy-dispersive X-ray spectroscopy (EDS. The UV-Vis absorption band increases, while the optical bandgap decreases when the amount of ZnO nanoparticles increases. ZnO nanoparticles apparently have no effect on the conjugation segments of MEH-PPV. PL spectra show that the emission peak increases and slightly red shift as ZnO concentration increases. Based on SEM images of MEH-PPV:ZnO nanocomposite thin films, ZnO nanoparticles form agglomerated regions.

  6. The mesospheric sodium layer as a remotely, optically pumped magnetometer for investigation of Birkeland currents

    Science.gov (United States)

    Johnsen, Magnar G.; Matzka, Jürgen; Hoppe, Ulf-Peter

    2016-04-01

    By means of optical pumping, it is possible to use the naturally occurring sodium layer in the mesosphere to measure Earth's scalar magnetic field at ~90 km above ground. This is an altitude not accessible by other means than rockets, which only will provide point measurements of very short time scales. We are planning to modify the sodium lidar at ALOMAR in Northern Norway to be able, for the first time, to measure and monitor the magnetic field in situ in the high latitude mesosphere over longer time scales. The planned modifications to the lidar instrument will allow alternating between the new magnetometer mode and its present mode for atmospheric temperatures and winds. The technique, which has been proposed earlier for measurements at low or mid-latitudes for studies of Earth's internal magnetic field, will in our project be applied to high latitudes in the auroral zone. This opens for a completely new domain of measurements of externally generated geomagnetic variations related to currents in the magnetosphere-ionosphere system. In particular, we aim to measure the magnetic field variations in close vicinity to Birkeland currents associated with particle precipitation events penetrating to altitudes below 90 km and small-scale, discrete auroral arcs. It is, furthermore, anticipated that it will be possible to detect horizontal current structures in the E-layer on much smaller length scales than it is presently possible from ground observations alone. During the project we plan take advantage of the rich space science infrastructure located in northern Norway, including ALOMAR, EISCAT and the Tromsø Geophysical Observatory magnetometer network. If possible, we also aim to make measurements in conjunction with overpasses of the SWARM satellites.

  7. Investigation of bracket bonding for orthodontic treatments using en-face optical coherence tomography

    Science.gov (United States)

    Sinescu, Cosmin; Negrutiu, Meda L.; Hughes, Michael; Bradu, Adrian; Todea, Carmen; Rominu, Roxana; Dodenciu, Dorin; Laissue, Philippe L.; Podoleanu, Adrian G.

    2008-04-01

    Despite good diagnosis and treatment planning, orthodontic treatment can fail if bonding fails. It is now common practice to address the aesthetic appearance of patients using aesthetic brackets instead of metal ones. Therefore, bonding aesthetic brackets has become an issue for orthodontists today. Orthodontic bonding is mainly achieved using composite resin but can also be performed with glass ionomer or resin cements. For improving the quality of bonding, the enamel is acid etched for 30 seconds with 38% phosphoric acid and then a bonding agent is applied. In our study we investigated and compared the quality of bonding between ceramic brackets, polymeric brackets and enamel, respectively using a new investigation method-OCT. The aim of our study was to evaluate the resin layer at the bracket base-tooth interface.

  8. Experimental Investigation of an Index-Mismatched Multiphase Flow Using Optical Techniques

    OpenAIRE

    Coronado Diaz, H.; Ronald J. Hugo

    2013-01-01

    An experimental investigation of multiphase flow involving a liquid (water) and a gas (air) is performed. The results for three different scenarios are presented: fixed bubble, ascending bubble, and dispersed-bubble turbulent pipe flow. This study involves a comparison of statistical data collected using two sensing systems, a wavefront sensor and a high-speed video camera. A signal analysis technique based on signal attenuation is developed for data collected using the wavefront sensor. The ...

  9. Investigation of in-vivo skin autofluorescence lifetimes under long-term cw optical excitation

    Energy Technology Data Exchange (ETDEWEB)

    Lihachev, A; Ferulova, I; Vasiljeva, K; Spigulis, J [Institute of Atomic Physics and Spectroscopy, University of Latvia, Riga (Latvia)

    2014-08-31

    The main results obtained during the last five years in the field of laser-excited in-vivo human skin photobleaching effects are presented. The main achievements and results obtained, as well as methods and experimental devices are briefly described. In addition, the impact of long-term 405-nm cw low-power laser excitation on the skin autofluorescence lifetime is experimentally investigated. (laser biophotonics)

  10. Status of the Synoptic Optical Long-Term Investigations of the Sun (SOLIS) Facility

    Science.gov (United States)

    Harvey, J.; SOLIS Team

    2003-05-01

    SOLIS is a suite of three instruments and a data handling system designed to provide synoptic solar observations for at least two decades. The facility is now commencing initial operations at a temporary observing site in Tucson. After a period of simultaneous observations with the NSO/NASA Kitt Peak spectromagnetograph, SOLIS will be moved to Kitt Peak where it will replace that instrument and the 30-year-old Vacuum Telescope. The SOLIS Vector SpectroMagnetograph (VSM) is a compact, helium-filled, high-throughput, 50-cm aperture telescope and spectrograph that nominally scans the entire solar disk in 15 minutes. It provides the first full-disk photospheric vector magnetograms, high-sensitivity photospheric and chromospheric longitudinal magnetograms, and 1083 nm He I chromospheric spectral maps. The VSM is initially operating with interim cameras that are noisier and slower than originally planned. A 15 cm Full Disk Patrol (FDP) instrument provides full-disk filtergrams captured by 2k x 2k CCD cameras using either a 1083 nm or a tunable (380-660 nm) narrow-band filter. Until it is finished, the tunable filter is temporarily replaced by an H-alpha filter. The VSM and FDP are mounted on separate declination axes attached to a right ascension drive. This allows the FDP to be pointed at the sun center while the VSM scans the solar disk in the declination direction. The final instrument is an Integrated Sunlight Spectrometer (ISS). The ISS is a double-pass spectrograph that produces high-quality spectra for sun-as-a-star studies. It is located in a temperature-controlled room and fed by a fiber-optic image-scrambling system that is mounted on the FDP. Data from all of the instruments is collected by an on-site storage area network and preliminary reduction done by a collection of 14 Linux computers. Archival storage of the data is on LTO tapes and the data products are transmitted to Tucson via a 45 Mbs link where they are kept on line and web-available using a RAID 5

  11. 75 FR 37994 - Airworthiness Directives; Bombardier, Inc. Model CL-600-1A11 (CL-600), CL-600-2A12 (CL-601), CL...

    Science.gov (United States)

    2010-07-01

    ... FR 6862). That NPRM proposed to correct an unsafe condition for the specified products. The MCAI... ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3..., Inc. Model CL-600-1A11 (CL- 600), CL-600-2A12 (CL-601), CL-600-2B16 (CL-601-3A, CL-601-3R, and CL-...

  12. Determination of 36Cl in nuclear waste from reactor decommissioning

    DEFF Research Database (Denmark)

    Hou, Xiaolin; Frøsig, Lars; Nielsen, Sven Poul

    2007-01-01

    An analytical method for the determination of Cl-36 in nuclear waste such as graphite, heavy concrete, steel, aluminum, and lead was developed. Several methods were investigated for decomposing the samples. AgCl precipitation was used to separate Cl-36 from the matrix elements, followed by ion...

  13. Investigation of the influence of the particle surface emission on the laser damage of optical materials

    Energy Technology Data Exchange (ETDEWEB)

    Astapenko, V.A. [Moscow Institute of Physics & Technology (Russian Federation); Pershin, V.F. [Kharkiv State Univ. (Russian Federation); Sidoryuk, O.E.; Skvortsov, L.A. [Polus Research Institute, Moscow (Russian Federation)

    1997-12-01

    The analysis of the under-threshold phenomena in the surface layer of the lithium niobate under intense laser irradiation was carried out. The accumulation effect leading to the laser damage was considered in the framework of the influence of the particle emission from the investigated sample surface on the electronic processes in the surface layer. The model of the oxygen depletion of the surface due to the intense nanosecond laser pulses is suggested. The influence of the adsorbed surface layer on this process is considered. This model is in agreement with the experimental data of the laser damage threshold dependence on the oxidizing/reduction properties of the environment.

  14. Comparative investigation of optical techniques for topography measurement of rough plastic surfaces

    DEFF Research Database (Denmark)

    Bariani, Paolo; Hansen, Hans Nørgaard; Arlø, Uffe Rolf;

    2003-01-01

    polypropylene parts manufactured by injection moulding. The mould was equipped with inserts with EDM machined surfaces (Sa  3.5 µm) in order to represent a typical tool surface for injection moulding. A focus detection laser scanning profiler, a confocal scanning laser microscope, a white light interferometer...... and, in addition, a scanning electron microscope, have been used in the analysis of plastic surfaces. This investigation has shown that topography assessment of rough plastic surfaces is critical to both white light interference microscope and confocal microscope while the focus detection laser...

  15. Effect of EtOH/MgCl2 Molar Ratios on the Catalytic Properties of MgCl2-SiO2/TiCl4 Ziegler-Natta Catalyst for Ethylene Polymerization

    OpenAIRE

    Piyasan Praserthdam; Supanan Patthamasang; Bunjerd Jongsomjit

    2011-01-01

    MgCl2-SiO2/TiCl4 Ziegler-Natta catalysts for ethylene polymerization were prepared by impregnation of MgCl2 on SiO2 in heptane and further treatment with TiCl4. MgCl2·nEtOH adduct solutions were prepared with various EtOH/MgCl2 molar ratios for preparation of the MgCl2-supported and MgCl2-SiO2-supported catalysts in order to investigate the effect on polymerization performance of both catalyst systems. The catalytic activities for ethylene polymerization decreased markedly with increased mola...

  16. Experimental Investigation of Coolant Mixing in WWER and PWR Reactor Fuel Bundles by Laser Optical Techniques for CFD Validation

    International Nuclear Information System (INIS)

    Non intrusive laser optical measurements have been carried out to investigate the coolant mixing in a model of the head part of a fuel assembly of a WWER reactor. The goal of this research was to investigate the coolant flow around the point based in-core thermocouple; and also provide experimental database as a validation tool for computational fluid dynamics calculations. The experiments have been carried out on a full size scale model of the head part of WWER-440/213 fuel assembly. In this paper first the previous results of the research project is summarised, when full field velocity vectors and temperature were obtained by particle image velocimetry and planar laser induced fluorescence, respectively. Then, preliminary results of the investigation of the influence of the flow in the central tube will be reported by presenting velocity measurement results. In order to have well measurable effect, extreme flow rates have been set in the central tube by applying an inner tube with controlled flow rates. Despite the extreme conditions, the influence of the central tube to the velocity field proved to be significant. Further measurement will be done for the investigation of the effect of the gaps at the spacer fixings by displacing the inner tube vertically, and also the temperature distribution will also be determined at similar geometries by laser induced fluorescence. The aim of the measurements was to establish an experimental database, as well as the validation of computational fluid dynamics calculations. (Authors)

  17. Computer investigation of ion beam optics for a Freeman type ion source system

    Energy Technology Data Exchange (ETDEWEB)

    Abdelrahman, M.M., E-mail: moustafa82003@yahoo.com [Accelerators and Ion Sources Department, Nuclear Research Center, Atomic Energy Authority, P.N. 13759, Inchas, Cairo (Egypt); Abdelsalam, F.W. [Accelerators and Ion Sources Department, Nuclear Research Center, Atomic Energy Authority, P.N. 13759, Inchas, Cairo (Egypt)

    2011-08-01

    The present work investigates the computer analysis of the ion beam properties produced by a Freeman type system. The extraction for such system is composed of four electrodes that permit to keep a fixed output energy by means of two accelerating gaps and one decelerating gap. The latter allows reducing the beam divergence angle. The combination of the acceleration/deceleration sections provides to keep a low beam emittance at the source outlet. The simulation of single charged argon ion trajectories for a plasma concave of curvature 4 mm was first studied with and without space charge effect using acceleration/deceleration extraction system with the aid of the SIMION computer program. The voltage applied to the accelerating electrode was optimized to accomplish the suitable ion trajectories without hitting the extraction electrode. Then, two additional studies were performed: the influence of the acceleration voltage and extraction voltage on the beam emittance and beam diameter; and the effect of the extraction gap width (distance between the plasma emission surface and the acceleration electrode) on the shape of the ion beam envelope and the position of the ion beam waist. Last, the influence of the space charge on the ion beam envelope was also investigated.

  18. Electrical and optical investigation on doping of II-VI compounds using radioactive isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Wienecke, Marion

    2000-12-15

    Using radioactive isotopes of shallow dopants (Ag, As, Rb) as well as of native or isoelectronic elements (Se, Te, Cd, Sr) which were incorporated as host atoms and then transmuted into relevant dopants (transmutation doping) we investigated doping phenomena occurring in the wide band gap II-VI compounds CdTe, ZnTe, ZnSe and SrS by the classical methods of semiconductor physics: Hall effect, C-V and photoluminescence measurements. Thus, we could assign unambiguously defect features in electrical and photoluminescence measurements to extrinsic dopants by means of the half lives of radioactive decay. In As doped ZnSe samples we observed two states: a metastable effective mass like state and a deep state. The occurrence of the latter state is always linked with the high resistivity of As doped ZnSe crystals. The transmutation doping experiments reveal that the so-called self-compensation typical for wide band gab II-VI compounds can be overcome when the thermal treatment for dopant incorporation is time separated from its electrical activation, achieved using transmutation at room temperature. Under these conditions we found an almost one-to-one doping efficiency relative to the implanted dose. Thus, these investigations are a contribution to understanding compensation phenomena occurring due to interactions between dopants and native defects during conventional doping treatments.

  19. Electrical and optical investigation on doping of II-VI compounds using radioactive isotopes

    Science.gov (United States)

    Wienecke, Marion

    2000-12-01

    Using radioactive isotopes of shallow dopants (Ag, As, Rb) as well as of native or isoelectronic elements (Se, Te, Cd, Sr) which were incorporated as host atoms and then transmuted into relevant dopants (transmutation doping) we investigated doping phenomena occurring in the wide band gap II-VI compounds CdTe, ZnTe, ZnSe and SrS by the classical methods of semiconductor physics: Hall effect, C-V and photoluminescence measurements. Thus, we could assign unambiguously defect features in electrical and photoluminescence measurements to extrinsic dopants by means of the half lives of radioactive decay. In As doped ZnSe samples we observed two states: a metastable effective mass like state and a deep state. The occurrence of the latter state is always linked with the high resistivity of As doped ZnSe crystals. The transmutation doping experiments reveal that the so-called self-compensation typical for wide band gab II-VI compounds can be overcome when the thermal treatment for dopant incorporation is time separated from its electrical activation, achieved using transmutation at room temperature. Under these conditions we found an almost one-to-one doping efficiency relative to the implanted dose. Thus, these investigations are a contribution to understanding compensation phenomena occurring due to interactions between dopants and native defects during conventional doping treatments.

  20. Investigations of morphology and optical properties of thin films of TiOPc/PTCDA donor acceptor couple

    Directory of Open Access Journals (Sweden)

    J. Weszka a,b

    2012-12-01

    Full Text Available Purpose: The aim of this work is studying surface topography and optical properties of organic thin films of TiOPc and PTCDA blends deposited by thermal vacuum evaporation.Design/methodology/approach: Thin films of blends of organic materials are provided as donor/acceptor couples in bulk heterojunction based organic solar cells. Thin films of TiOPc - PTCDA mixture have been deposited by thermal vacuum evaporation from one source with various ratios of blends components and deposition rates used. Both the chemical composition and technological parameters of the deposition process have appeared to influence on optical properties, UV-Vis absorption spectra in particular, and surface morphology of the as-prepared thin films. The paper reveals the methodology of deposition thin films of TiPc-PTCDA donor/acceptor blends and the influence of deposition parameters on their properties.Findings: Thin films of such blends can be used for the research on the planar heterojunction solar cells based on donor–acceptor couple active layers. Results of these investigations suggest that blends of TiOPc and PTCDA can be suitable materials for preparing organic photovoltaic devices.Research limitations/implications: Deposition parameters and proportions of the blend components used determine the properties of TiOPc/PTCDA thin films.Originality/value: The goal of this paper is also to define relations connecting the surface morphology and optical properties of thin films of TiOPc-PTCDA blend prepared with their composition and parameters of the evaporation process.

  1. Investigation of the optical and structural properties of WO3 thin films with different sputtering power supplies

    Science.gov (United States)

    Chen, Hsi-Chao; Jan, Der-Jun; Chen, Chien-Han; Huang, Kuo-Ting; Luo, Yu-Siang; Chen, Jia-Min

    2012-10-01

    The purpose of this research was to investigate the optical and structural properties of tungsten oxide (WO3) thin films deposited with three different sputtering power supplies: direct current (DC), DC pulse and radio frequency (RF). These WO3 thin films were deposited on ITO glass and silicon substrate with different gas ratios of oxygen and argon (O2/Ar ratio). WO3 thin film is the role of the electrochromic window was resulted from the advantages of large variation in optical density, high response efficiency, no toxicity and low cost. The experimental results showed that optical intensity increased with the increasing of O2/Ar ratio and all films have the 950cm-1 peak which the bonding of W+6=O in Raman spectra. Hence, the O2/Ar ratio was changed from 0.4 to 0.8 to study the ability of coloring and bleaching for the three different power supplies. Anyways, the WO3 thin films had the best electrochromic property at the O2/Ar ratio of 0.7, 0.6 and 0.6 for DC, DC pulse, and RF, respectively. The transmittances could be over 75% for all films at as-deposited and the deposition rates were between 0.8 and 0.1 Ås-1. Simultaneously, the transmittance variations (ΔT) were 51%, 57% and 53% for DC, DC pulse, and RF power sources at wavelength of 550 nm, respectively. The coloration ability of WO3 thin film deposition with power supply of DC pulse was better than that of the DC and RF.

  2. LiCl(NaCl)-CeCl3-H2O systems at 25 deg C

    International Nuclear Information System (INIS)

    It has been found by the method of isothermal solubility that aqueous ternary systems LiCl(NaCl)-CeCl3-H2O at 25 deg C refer to the eutonic type with crystallization of the initial components LiClxH2O, NaCl, and CeCl3x7H2O

  3. Time dependent DFT investigation of the optical properties of artificial light harvesting special pairs.

    Science.gov (United States)

    Agnihotri, Neha; Steer, Ronald P

    2016-06-01

    Computational modeling of selected artificial special pairs has been carried out. The structures chosen are bio-inspired molecular models of the light harvesting system II that have been previously investigated experimentally. Time-dependent density functional theory calculations have been employed to characterize the inter-macrocycle interactions resulting from two zinc porphyrins that are covalently linked with rigid linkers that vary the inter-porphyrin distance and the inter-planar angle in a C2v framework. The effects of varying the linker structure have been explored for electronic states with energies up to and including the Soret-correlated states in the dimer. An expansion of the Gouterman four orbital model for the monomers to an eight orbital model in the dimers provides a reasonable explanation of the inter-macrocycle interactions and provides insight into their experimental properties. PMID:27212274

  4. Experimental Investigation on Transmission Control Protocol Throughput Behavior in Optical Fiber Access Networks

    Science.gov (United States)

    Tego, Edion; Matera, Francesco; del Buono, Donato

    2016-03-01

    This article describes an experimental investigation on the behavior of transmission control protocol in throughput measurements to be used in the verification of the service-level agreement between the Internet service provider and user in terms of line capacity for ultra-broadband access networks typical of fiber-to-the-x architectures. It is experimentally shown different conditions in high bandwidth-delay product links where the estimation of the line capacity based on a single transmission control protocol session results are unreliable. Simple equations reported in this work, and experimentally verified, point out the conditions in terms of packet loss, time delay, and line capacity, that allow consideration of the reliability of the measurement carried out with a single transmission control protocol session test by adopting a suitable measurement time duration.

  5. Investigation of durability of optical coatings in highly purified tritium gas

    International Nuclear Information System (INIS)

    Anti-reflection coated windows are part of Raman spectroscopy systems for tritium analytics in the KATRIN experiment and fusion-related applications. Damages of such windows were observed after three months of expo-sure to highly purified tritium gas in the LOOPINO facility. In this work, the origin of the damages was investigated, identified and eliminated. Coating samples manufactured by various physical vapor deposition methods have been tested for durability by exposure to pure tritium gas and subsequent visual inspection. Electron beam deposited coatings showed indications for damage after 17 days of tritium exposure in contrast to samples manufactured by ion assisted deposition or sputtering. An improved coating layout of the sample cell is presented for reliable long-term monitoring of tritium gas using Raman spectroscopy. (authors)

  6. Investigation of Electron Transfer-Based Photonic and Electro-Optic Materials and Devices

    Energy Technology Data Exchange (ETDEWEB)

    Bromenshenk, Jerry J; Abbott, Edwin H; Dickensheets, David; Donovan, Richard P; Hobbs, J D; Spangler, Lee; McGuirl, Michele A; Spangler, Charles; Rebane, Aleksander; Rosenburg, Edward; Schmidt, V H; Singel, David J

    2008-03-28

    Montana's state program began its sixth year in 2006. The project's research cluster focused on physical, chemical, and biological materials that exhibit unique electron-transfer properties. Our investigators have filed several patents and have also have established five spin-off businesses (3 MSU, 2 UM) and a research center (MT Tech). In addition, this project involved faculty and students at three campuses (MSU, UM, MT Tech) and has a number of under-represented students, including 10 women and 5 Native Americans. In 2006, there was an added emphasis on exporting seminars and speakers via the Internet from UM to Chief Dull Knife Community College, as well as work with the MT Department of Commerce to better educate our faculty regarding establishing small businesses, licensing and patent issues, and SBIR program opportunities.

  7. The spectroscopic investigation of the optical and electronic properties of SWCNT

    International Nuclear Information System (INIS)

    The spectroscopic investigation of bulk samples of SWCNT is reviewed with examples taken from electron energy-loss spectroscopy in transmission, UV-vis and photoemission spectroscopy. It is shown that, given the insight obtained from EELS studies, UV-vis spectroscopy is a powerful express tool for the characterization of the NT yield and diameter distribution in bulk SWCNT samples. In addition, using photoemission spectroscopy, apart from showing the use of annealing in UHV to remove many of the contaminants commonly found in purified SWCNT material and determining the work function of pristine SWCNT to be 4.65±0.1 eV, we illustrate the similarity of the occupied electronic structure of SWCNT with that of graphite. Open questions, however, remain, such as the appropriate model for the changes of the electronic structure upon intercalation and the reasons for the absence of the singularities in the occupied density of states in the photoemission spectra

  8. Optical investigations of powerful laser actions on massive and flyer targets

    International Nuclear Information System (INIS)

    In this paper we present experimental, theoretical, and computer simulation studies of craters formation produced by high power lasers in single and double layer targets. The experimental investigation was carried out using the PALS (Prague Asterix Laser System) facility working with two different laser beam wavelengths: λ1 = 1.315 μm and λ3 0.438 μm. Two types of targets made of Al were used: single massive targets and double targets consisting of a foil or disk (6 μm and 11 μm thick for both cases) placed in front of the massive target at the distance of 200-500 μm. Experiments with single massive targets were performed at laser intensities in the range of 1013-1015 W/cm2 by varying the laser beam diameter on the target surface from 70 μm up to 1200 μm (moving the target away from the focus). The double targets were illuminated by laser energies EL = 100-500 J always focused on diameter of 250 μm. In all experiments performed the laser pulse duration was equal to 400 ps. The 3-frame interferometry was employed to investigate the plasma dynamics by means of the electron density distribution time development as well as the disks and foil fragments velocity measurements. Dimensions and shapes of craters were obtained by crater replica technology and microscopy measurement. Experimental results were complemented by two-dimensional analytical theory and computer simulations to help their interpretation. This way the values of laser energy absorption coefficient, ablation loading efficiency and efficiency of energy transfer as well as two-dimensional shock wave generation at the laser-driven macro-particle impact were obtained from measured craters' parameters for both wavelengths of laser radiation. (author)

  9. Ellipsoidal primary of the RS CVn binary zeta And: Investigation using high-resolution spectroscopy and optical interferometry

    CERN Document Server

    Korhonen, H; Kovari, Zs; Granzer, Th; Hackman, T; Strassmeier, K G

    2010-01-01

    We have obtained high-resolution spectroscopy, optical interferometry, and long-term broad band photometry of the ellipsoidal primary of the RS CVn-type binary system zeta And. Based on the optical interferometry the apparent limb darkened diameter of zeta And is 2.55 +/- 0.09 mas using a uniform disk fit. The Hipparcos distance and the limb-darkened diameter obtained with a uniform disk fit give stellar radius of 15.9 +/- 0.8 Rsolar, and combined with bolometric luminosity, it implies an effective temperature of 4665 +/- 140 K. The temperature maps obtained from high resolution spectra using Doppler imaging show a strong belt of equatorial spots and hints of a cool polar cap. The equatorial spots show a concentration around the phase 0.75. This spot configuration is reminiscent of the one seen in the earlier published temperature maps of zeta And. Investigation of the Halpha line reveals both prominences and cool clouds in the chromosphere. Long-term photometry spanning 12 years shows hints of a spot activit...

  10. Real-time optical modelling and investigation of inorganic nano-layer growth onto flexible polymeric substrates

    International Nuclear Information System (INIS)

    A major factor for the achievement of the desirable performance, efficiency and lifetime of flexible organic electronic devices is the optimization of the encapsulation layers that protect the device active layers by atmospheric gas molecule permeation. The active layers consisted of small molecule and/or polymer organic semiconductors as well as the organic conductors need to be encapsulated into a transparent medium that will provide the necessary protection and maintain their charge generation and transport characteristics. The encapsulation layers are generally consisted of inorganic thin films (silicon oxide-SiOx and aluminium oxide-AlOx) deposited onto the polymeric substrates, such as PolyEthylene Terephthalate (PET). In this work, in situ and real-time Spectroscopic Ellipsometry in the ultraviolet spectral region has been implemented in order to investigate the growth of inorganic SiOx and AlOx nano-layers onto PET flexible polymeric substrates as well as the PET/inorganic interface effects during the early stages of growth. The analysis of the pseudodielectric function that was measured in real-time in very short time scales (in the order of hundreds of ms) has provided detailed information on the time evolution of the thickness and deposition rate of the inorganic nano-layers during their growth process as well as on their optical and electronic properties. This work proposes a methodology for using real-time optical monitoring technique with the aim to tailor and control the functionality of these materials for application in flexible electronic devices.

  11. In-vivo Fourier domain optical coherence tomography as a new tool for investigation of vasodynamics in the mouse model

    Science.gov (United States)

    Meissner, Sven; Müller, Gregor; Walther, Julia; Morawietz, Henning; Koch, Edmund

    2009-05-01

    In-vivo imaging of the vascular system can provide novel insight into the dynamics of vasoconstriction and vasodilation. Fourier domain optical coherence tomography (FD-OCT) is an optical, noncontact imaging technique based on interferometry of short-coherent near-infrared light with axial resolution of less than 10 μm. In this study, we apply FD-OCT as an in-vivo imaging technique to investigate blood vessels in their anatomical context using temporally resolved image stacks. Our chosen model system is the murine saphenous artery and vein, due to their small inner vessel diameters, sensitive response to vasoactive stimuli, and advantageous anatomical position. The vascular function of male wild-type mice (C57BL/6) is determined at the ages of 6 and 20 weeks. Vasoconstriction is analyzed in response to dermal application of potassium (K+), and vasodilation in response to sodium nitroprusside (SNP). Vasodynamics are quantified from time series (75 sec, 4 frames per sec, 330×512 pixels per frame) of cross sectional images that are analyzed by semiautomated image processing software. The morphology of the saphenous artery and vein is determined by 3-D image stacks of 512×512×512 pixels. Using the FD-OCT technique, we are able to demonstrate age-dependent differences in vascular function and vasodynamics.

  12. Investigation of structural and optical properties of ZnO films co-doped with fluorine and indium

    Science.gov (United States)

    Keskenler, E. F.; Turgut, G.; Doğan, S.

    2012-07-01

    Undoped ZnO film and ZnO films, which are co-doped with F and In (FIZO) at different concentrations, were synthesized by sol-gel technique and the effects of co-doping of F and In on structural and optical properties of ZnO thin films were investigated. The concentration ratio of [F]/[Zn] was altered from 0.25 to 1.75 with 0.50 step at.% mole and [In]/[Zn] was altered from 0.25 to 1.00 with 0.25 step at.% mole. X-ray diffraction analysis indicates that the films have polycrystalline nature and the (0 0 2) preferred orientation is the stronger peak. No extra phases involving zinc, fluorine and indium compounds were observed even at high F and In content. The grain size of undoped ZnO and FIZO thin films varied between 15 and 20 nm with a small fluctuation. From the SEM images, although the undoped ZnO had a smooth and particle-shaped surface, FIZO films had nanofiber-networks shapes over the surface with average size of 500 nm. The surface morphologies and crystallite sizes for the F and In doped films were slightly different from than those of undoped film. From the optical study, a slight shrinkage of band gap was backwardly observed from 3.36 to 3.25 eV with the increasing of F and In content.

  13. Investigation of Cu Doping, Morphology and Annealing Effects on Structural and Optical Properties of ZnO:Dy Nanostructures.

    Science.gov (United States)

    Najafi, Mehrdad

    2016-05-01

    Dysprosium (Dy) doped ZnO nanosheets and nanorods were synthesized by hydrothermal method. Effects of Cu doping, morphology and annealing in Oxygen ambient on structural and optical properties of ZnO nanostructures were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectra (DRS) and photoluminescence (PL) spectroscopy. This study recommends that both of intrinsic and extrinsic defects facilitate energy transfer (ET) from the ZnO host to Dy(3+) ions and consequently have an effective role on producing intense Dy emissions at indirect excitation. The results also revealed that annealing process improved the crystal structure of ZnO nanorods due to decrease of surface; however decreased ET and Dy emissions because of diminishing in oxygen vacancy. In addition, as a result of increasing of surface area in nanorods compared to nanosheets, the oxygen vacancies and ET were enhanced. Moreover the results exhibited that electrical and optical properties of ZnO:Dy can be tuned by various amount of Dy concentrations and also Cu doping. PMID:26798063

  14. Correlation effect investigations on the Magneto-optical Kerr Spectra of Co-based Heusler alloys from first principles

    Science.gov (United States)

    Kim, Miyoung; Lim, Hanjo; Lee, Jae Il

    2011-03-01

    Here, we report our ab-initio calculational results on the electronic structures and magneto-optical (MO) properties of the ferromagnetic Co 2 Mn X full Heusler alloys. Employing the +U corrections for the transition metal 3 d bands in addition to the local density approximation (LDA), we investigate the correlation effect on the MO spectra in polar geometry as well as the detailed electronic structures using FLAPW method. Results show that the correlation effect results in a blue-shift of the peak positions and large enhancement of the low energy MO spectra, which are attributed to the increased t 2g - e g splitting of spin minority Co and Mn d - bands indicating the suppression of diagonal elements of optical conductivity at energy region of 1 ~ 2 eV where the interband transitions are forbidden. This work is supported by Korean Research Foundation Grant by MOEHRD (KRF 2007-412-J04001) and also by Basic Science Research Program through the National Research Foundation of Korea (NRF-2010-0005387).

  15. Single particle optical investigation of gold shell enhanced upconverted fluorescence emission

    Science.gov (United States)

    Green, Kory; Lim, Shuang Fang; Hallen, Hans

    2014-03-01

    Upconverting nanoparticles (UCNPs) excited in the near IR offer novel advantages as fluorescent contrast agents, allowing for background free bio-imaging. However, their fluorescence brightness is hampered by low quantum efficiency due to the low absorption cross section of Ytterbium and Erbium ions in the near IR. We enhance the efficiency of these particles by investigating the plasmonic coupling of 30nm diameter core NaYF4: Yb, Er upconverting particles (UCNPs) with a gold shell coating. An enhancement of green emission by a factor of five and a three times overall increase in emission intensity has been achieved for single particle spectra. UV-Vis absorption has confirmed the surface plasmon resonance (SPR) of the gold shell to the near IR and transmission electron microscope (TEM) images demonstrates successful growth of a gold shell around the upconversion particle. Time-resolved spectroscopy shows that gold shell coupling changes the lifetime of the energy levels of the Erbium ion that are relevant to the emission process.

  16. Direct-injection strategies for a hydrogen-fueled engine : an optical and numerical investigation

    International Nuclear Information System (INIS)

    Vehicles with hydrogen-fueled engines are competitive with systems based on fuel cells. There is a lack of fundamental knowledge about in-cylinder processes in hydrogen direct injection engines. This presentation discussed a study that used a variety of injector configurations to establish a broad database. A light-load conditions that can profit from stratification was investigated. Several results were presented, including the 5-hole nozzle produced an asymmetric jet pattern which may be good for late injection. Very lean regions in the wake of the transient jets were found to be similar to those found in diesel injection. The 13-hole nozzle demonstrated complete jet collapse, consistent with Schlieren imaging by Petersen. Stratification made efficiency sensitive to the targeting of the single-hole injector. Computational fluid dynamics with a commercially available code aimed to improve the process of design optimization. The simulation predicted less fuel dispersion than was experimentally measured. Details of the fuel penetration were captured. It was concluded that for the single-hole nozzle, the pre-spark fuel distribution is consistent with results from the fired engine. tabs., figs.

  17. Experimental investigation of PAM, CAP and DMT modulations efficiency over a double-step-index polymer optical fiber

    Science.gov (United States)

    Stepniak, G.; Siuzdak, J.

    2014-08-01

    Investigated was the transmission over step index POF that is 50 m/100 m long with a red DVD laser as a source and a Si p-i-n commercial photo-detector. The maximum bit rates of three modulation formats: PAM, CAP and DMT were sought. Their constellation sizes and symbol rates were varied in order to maximize FEC limited throughputs for each modulation whereas the laser operating point and relevant optical powers were maintained constant for all the modulations. The maximum throughputs were similar for PAM and CAP, namely 3.3/2 Gbit/s for PAM, and 3.15/2.1 for CAP for 50/100 m fiber, respectively. The bit rates for DMT were 2.65/1.65 Gbit/s for the respective lengths of the fiber. We attribute the inferior performance of DMT to its high value of peak to average power ratio.

  18. Electro-optic investigation of the surface trapping efficiency in n-alkanethiol SAM passivated GaAs(001)

    International Nuclear Information System (INIS)

    The electro-optic characteristics of the semi-insulating and n+-type GaAs(001) surfaces passivated with n-alkanethiol self-assembled monolayers were investigated using Kelvin probe surface photovoltage (SPV) and photoluminescence (PL) techniques. Referencing the equilibrium surface barrier height established in an earlier report, SPV measurements demonstrated a significant (>100 mV) increase in the non-equilibrium band-bending potential observed under low-level photo-injection. Modeling of the SPV accounts for these observations in terms of a large (>104) decrease in the hole/electron ratio of surface carrier capture cross-sections, which is suggested to result from the electrostatic potential of the interfacial dipole layer formed upon thiol chemisorption. The cross-section effects are verified in the high-injection regime based on carrier transport modeling of the PL enhancement manifested as a reduction of the surface recombination velocity.

  19. Theoretical investigations of the optical and EPR spectra for trivalent cerium and ytterbium ions in orthorhombic YF3 crystal

    Science.gov (United States)

    Liu, Hong-Gang; Zheng, Wen-Chen

    2016-09-01

    The optical spectra and electron paramagnetic resonance (EPR) parameters (g factors and hyperfine structure constants A) for trivalent cerium and ytterbium ions in YF3 crystal with orthorhombic structure are investigated together by the complete diagonalization (of energy matrix) method (CDM). The obtained results are in reasonable agreement with the experimental ones. More importantly, two magnetically nonequivalent centers in YF3 crystal observed in EPR experiments are confirmed and ascribed to their specific positions in a unit cell by our calculations based on superposition model (SPM) analysis. Such identification of local sites with different magnetic properties would help us to understand not only the EPR spectra and magnetic susceptibility of other lanthanide ions doped in crystals with the same structure as YF3 but also the energy transfer scheme between two lanthanide ions occupying such two sites. All results are discussed carefully.

  20. Investigation of optical and electrical properties of amorphous Se95−xSxZn5(x=0.2, 2, 5 and 10) thin films

    International Nuclear Information System (INIS)

    In this study, we reported that the optical and electrical analysis of amorphous Se90-xSxZn5 (x=0.2, 2, 5, 10) thin films. Bulk samples of the investigated material were prepared by melt quenching technique. Thin films of ~ 300nm thickness were deposited on cleaned glass substrates by thermal evaporation technique. The morphological study of the investigated material in powder form carried out by scanning electron microscopy (SEM) confirms the disorder of the material increases at lower sulfur doping (up to 5%) whereas at higher (S) doping (10%) the defects of the material decreases. The optical parameters were estimated from optical absorption spectra data measured from UV-Vis-spectrophotometer in the wavelength range 200-900 nm. It was found that the value of optical band gap (Eg) of the investigated thin films decreases up to lower S doping and increases at higher (S) doping. The other optical parameters such as absorption coefficient (α) and extinction coefficient (K) increases up to lower S doping and decreases at higher S doping. This remarkable change in the values of optical parameters was interpreted on the basis of model proposed by Davis and Mott. Electrical parameters of the investigated thin films were carried out in the temperature range 309-370 K. Analysis of data shows activation energy decreases with the increase of concentration of (S) increases up to 5% and at 10% it increases again