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Sample records for 30w 1178nm yb-doped

  1. 30W, 1178nm Yb-doped photonic bandgap fiber amplifier

    DEFF Research Database (Denmark)

    Shirakawa, Akira; Maruyama, Hiroki; Ueda, Ken-ichi;

    2009-01-01

    High-power, high-efficiency ytterbium-doped solid-core photonic-bandgap fiber amplification at the long-wavelength edge of the Yb gain band is reported. Amplified-spontaneous-emission-free, 30W nonpolarized and 25W linearly-polarized 1178nm outputs have been achieved with

  2. Large-mode-area hybrid photonic crystal fiber amplifier at 1178 nm

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Chen, Mingchen; Shirakawa, Akira;

    2015-01-01

    Amplification of 1178 nm light is demonstrated in a large-mode-area single-mode ytterbium-doped hybrid photonic crystal fiber, relying on distributed spectral filtering of spontaneous emission at shorter wavelengths. An output power of 53 W is achieved with 29 dB suppression of parasitic lasing...

  3. Compact, Low Threshold Nd3+:YVO4 Self-Raman Laser at 1178nm

    Institute of Scientific and Technical Information of China (English)

    WANG Bao-Shan; TAN Hui-Ming; GAO Lan-Lan; PENG Ji-Ying; MIAO Jie-Guang

    2006-01-01

    @@ A compact low-threshold Raman laser at 1178nm is experimentally realized by using a diode-end-pumped actively Q-switched Nd3+ : YVO4 self-Raman laser. The threshold is 370mW at a pulse repetition frequency of 5 kHz. The maximum Raman laser output is 182mW with the pulse duration smaller than 20ns at a pulse repetition frequency of 30 kHz with 1.8W incident power. The optical efficiency from the incident power to the Raman laser is 10% and the slope efficiency is 13.5%.

  4. 1178 nm all Yb-fiber laser source power-scaled by solid-core photonic bandgap fiber for 589nm generation

    DEFF Research Database (Denmark)

    Maruyama, H.; Shirakawa, A.; Ueda, K.I.;

    2009-01-01

    Here we report an 1178 nm all Yb-fiber laser source power-scaled by solid-core photonic bandgap fiber (SC-PBGF) for 589 nm generation. A 1.4 W output at 589 nm with an input power of 9 W at 1178 nm were obtained. One important advantage of PBGF is distributed filtering. Hence the gain spectrum can...

  5. Coherent combining in an Yb doped double core fiber laser

    CERN Document Server

    Boullet, Johan; Desfarges-Berthelemot, Agnès; Kermène, Vincent; Pagnoux, Dominique; Roy, Philippe; Dussardier, Bernard; Blanc, Wilfried; 10.1364/OL.30.001962

    2012-01-01

    Coherent combining is demonstrated in a clad pumped Yb doped double core fiber laser. A slope efficiency of more than 70 % is achieved with 96 % of the total output power on the fundamental mode of one of the two cores. This high combining efficiency is obtained when both cores are coupled via a biconical fused taper in a Michelson interferometer configuration.

  6. Guided mode gain competition in Yb-doped rod-type photonic crystal fibers

    DEFF Research Database (Denmark)

    Poli, Federica; Passaro, Davide; Cucinotta, Annamaria;

    2009-01-01

    The gain competition among the guided modes in Yb-doped rod-type photonic crystal fibers with a low refractive index core is investigated with a spatial model to demonstrate the fiber effective single-mode behaviour.......The gain competition among the guided modes in Yb-doped rod-type photonic crystal fibers with a low refractive index core is investigated with a spatial model to demonstrate the fiber effective single-mode behaviour....

  7. Synthesis and characterization of (Ba,Yb doped ceria nanopowders

    Directory of Open Access Journals (Sweden)

    Branko Matović

    2011-06-01

    Full Text Available Nanometric size (Ba, Yb doped ceria powders with fluorite-type structure were obtained by applying selfpropagating room temperature methods. Tailored composition was: Ce0.95−xBa0.05YbxO2−δ with fixed amount of Ba − 0.05 and varying Yb content “x” from 0.05 to 0.2. Powder properties such as crystallite and particle size and lattice parameters have been studied. Röntgen diffraction analyses (XRD were used to characterize the samples at room temperature. Also, high temperature treatment (up to 1550°C was used to follow stability of solid solutions. The mean diameters of the nanocrystals are determined from the full width at half maxima (FWHM of the XRD peaks. It was found that average diameter of crystallites is less than 3 nm. WilliamsonHall plots were used to separate the effect of the size and strain in the nanocrystals.

  8. Femtosecond pulse generation and amplification in Yb-doped fibre oscillator–amplifier system

    Indian Academy of Sciences (India)

    P K Mukhopadhyay

    2010-11-01

    In recent times ytterbium (Yb) doped fibre-based mode-locked master oscillator and power amplifier have attracted a great deal of interest because of their inherent advantages like flexibility, reliability, compactness, high power handling capability and diffraction limited output beam quality as compared to the solid-state counterpart. But, to successfully develope of high-power femtosecond oscillator–amplifier system based on Yb- doped fibre, an appropriate choice of the mode-locking regime and the amplifier geometry are required. Development of an all-fibre integrated high-power Yb-doped fibre oscillator–amplifier system in which the advantages of a fibre-based system can be fully exploited remained a challenge as it requires the careful optimization of dispersion, nonlinearity, gain and ASE contribution. In this article, femto-second pulse generation in Yb-doped fibre oscillator in different mode-locking regimes are reviewed and the details of development and characterization of an all-fibre, high-power, low-noise amplifier system seeded by an all-normal-dispersion mode-locked Yb-doped fibre laser oscillator is described. More than 10 W of average power is obtained from the fibre oscillator–amplifier system at a repetition rate of 43 MHz with diffraction-limited beam quality. Amplified pulses are de-chirped to sub-160 fs duration in a grating compressor. This is the first 10 W-level source of femtosecond pulses with completely fibre-integrated amplification comprised of commercially available components.

  9. Tunable passively harmonic mode-locked Yb-doped fiber laser with Lyot-Sagnac filter.

    Science.gov (United States)

    Li, Ming; Zou, Xin; Wu, Jian; Shi, Jindan; Qiu, Jifang; Hong, Xiaobin

    2015-10-10

    A novel passively harmonic mode-locked dissipative soliton Yb-doped fiber laser with all normal dispersion is proposed and experimentally demonstrated based on a semiconductor saturable absorption mirror and tunable Lyot-Sagnac filter. By only tuning the bandwidth of the filter at fixed pump power, the repetition rate of 9.87 to 167.8 MHz (corresponding to 17th-order harmonic) is obtained. This is the highest repetition rate and harmonic order for a passively harmonic mode-locked dissipative soliton Yb-doped fiber laser with all-normal dispersion to the best of our knowledge. The signal-to-noise ratio and super-mode suppression ratio for all harmonic orders are higher than 65 and 35 dB, respectively, which shows the high stability of the fiber laser. PMID:26479821

  10. Experimental observation of soliton molecule evolution in Yb-doped passively mode-locked fiber lasers

    International Nuclear Information System (INIS)

    We have observed soliton molecules with variable modulation depth of spectra in a passively mode-locked dispersion-managed Yb-doped fiber laser. The soliton molecule we experimentally investigated presents diatomic and tetratomic types. With the enhancement of pump power, the laser alternately operates at solitons molecule, temporal-separation-oscillation solitons, and harmonic mode-locked states. Moreover, the phase of solitons molecule is only locked at low pump, and excess pump would cause phase vibration. (letters)

  11. Generation of sub-50 fs pulses from a high-power Yb-doped fiber amplifier.

    Science.gov (United States)

    Deng, Yujun; Chien, Ching-Yuan; Fidric, Bernard G; Kafka, James D

    2009-11-15

    We demonstrate the generation of 48 fs pulses with 18 W average power and 226 nJ of pulse energy from a Yb-doped fiber amplifier. The system uses a simple stretcher-free single-stage amplifier configuration operating in the parabolic pulse regime. The gain fiber length and pump wavelength are chosen in order to reduce the gain per unit length and generate both shorter pulses and higher pulse energy.

  12. High-power Yb-doped continuous-wave and pulsed fibre lasers

    Indian Academy of Sciences (India)

    B N Upadhyaya

    2014-01-01

    High-power laser generation using Yb-doped double-clad fibres with conversion efficiencies in excess of 80% have attracted much attention during the last decade due to their inherent advantages in terms of very high efficiency, no misalignment due to in-built intracore fibre Bragg gratings, low thermal problems due to large surface to volume ratio, diffraction-limited beam quality, compactness, reliability and fibre-optic beam delivery. Yb-doped fibres can also provide a wide emission band from ∼1010 nm to ∼1170 nm, which makes it a versatile laser medium to realize continuous-wave (CW), Q-switched short pulse, and mode-locked ultrashort pulse generation for various applications. In this article, a review of Yb-doped CW and pulsed fibre lasers along with our study on self-pulsing dynamics in CW fibre lasers to find its role in high-power fibre laser development and the physical mechanisms involved in its generation has been described. A study on the generation of high-power CWfibre laser of 165Woutput power and generation of high peak power nanosecond pulses from acousto-optic Q-switched fibre laser has also been presented.

  13. Influence of Yb-Doped Nanoporous TiO2 Films on Photovoltaic Performance of Dye-Sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    XU Wei-Wei; DAI Song-Yuan; HU Lin-Hua; LIANG Lin-Yun; WANG Kong-Jia

    2006-01-01

    @@ Yb-doped TiO2 pastes with different Yb/TiO2 weight ratios are prepared in the sol-gel process to obtain dyesensitized solar cells (DSCs). The nanocrystalline size of Yb-TiO2 becomes smaller and the lattice parameters change. Lattice distortion is observed and dark current is detected. It is found that a part of Yb existing as insulating oxide Yb2Oa state acts as barrier layers at the electrode-electrolyte interface to suppress charge recombination. A Yb-doped TiO2 electrode applied in DSCs leads to a higher open-circuit voltage and a higher fill factor. How the Yb-doped TiO2 films affect the photovoltaic response of DSCs is discussed.

  14. Passive harmonic mode locked all-normal-dispersion Yb-doped fibre lasers

    Institute of Scientific and Technical Information of China (English)

    Kong Ling-Jie; Xiao Xiao-Sheng; Yang Chang-Xi

    2011-01-01

    Passive harmonic mode-locking of dissipative solitons is demonstrated in all-normal dispersion Yb-doped fibre lasers. A difference equation model of the mode-locked fibre lasers is adopted to simulate the intra-cavity nonlinear dynamics. Hysteresis phenomena around the mode-locking threshold, and the effect of introducing linear phase bias are discussed. The passive harmonic mode-locking as one kind of multipulsing operations is revealed. Moreover, the simulation shows the bistability between multipulsing and single-pulse or period multiplication.

  15. Pulsed pumped Yb-doped fiber amplifier at low repetition rate

    Institute of Scientific and Technical Information of China (English)

    Changgeng Ye; Ping Yan; Mali Gong; Ming Lei

    2005-01-01

    A pulsed pumped Yb-doped double-clad fiber (DCF) master-oscillator power amplifier (MOPA) at low repetition rate is reported. Seeded by a passive Q-switched Nd:YAG microchip laser, the fiber amplifier can generate 167-kW peak-power and 0.83-ns duration pulses at 200-Hz repetition rate. Because of the pulsed pump approach, the amplified spontaneous emission (ASE) and the spurious lasing between pulses are well avoided, and the repetition rate can be set freely from single-shot to 1 kHz. Peak power scaling limitations that arise from the fiber facet damage are discussed.

  16. Yb-doped phosphate double-cladding optical fiber laser for high-power applications

    OpenAIRE

    Mura, Emanuele; Lousteau, Joris; Boetti, Nadia Giovanna; Scarpignato, Gerardo Cristian; Milanese, Daniel

    2013-01-01

    A Yb-doped phosphate glass double cladding optical fiber was prepared using a custom designed glass composition (P2O5 - Al2O3 - Li2O - B2O3 - BaO - PbO - La2O3) for high-power amplifier and laser applications. The preform drawing method was followed, with the preform being fabricated using the rotational casting technique. This technique, previously developed for tellurite, fluoride or chalcogenide glass preforms is reported for the first time using rare earth doped phosphate glasses. The mai...

  17. Sectioned Core Doping Effect on Higher-Order Mode Amplification in Yb-Doped Rod-Type Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Poli, F.; Lægsgaard, Jesper; Passaro, D.;

    2009-01-01

    The amplification properties of guided modes in Yb-doped rod-type photonic crystal fibers with sectioned core doping have been investigated, evaluating the doped-area radius which provides the effective suppression of both LP 11- and LP02-like modes.......The amplification properties of guided modes in Yb-doped rod-type photonic crystal fibers with sectioned core doping have been investigated, evaluating the doped-area radius which provides the effective suppression of both LP 11- and LP02-like modes....

  18. Spectroscopic and crystal-field analysis of new Yb-doped laser materials

    Energy Technology Data Exchange (ETDEWEB)

    Haumesser, Paul-Henri; Gaume, Romain; Antic-Fidancev, Elisabeth; Vivien, Daniel; Viana, Bruno [Laboratoire de Chimie Appliquee de l' Etat Solide UMR 75 74, ENSCP, Paris (France)]. E-mail: viana@ext.jussieu.fr

    2001-06-11

    Crystal-field effects are very important as far as laser performances of Yb-doped materials are concerned. In order to simplify the interpretation of low-temperature spectra, two tools derived from a careful examination of crystal-field interaction are presented. Both approaches are successfully applied in the case of new Yb-doped materials, namely Ca{sub 3}Y{sub 2}(BO{sub 3}){sub 4} (CYB), Ca{sub 3}Gd{sub 2}(BO{sub 3}){sub 4} (CaGB), Sr{sub 3}Y(BO{sub 3}){sub 3} (SrYBO), Ba{sub 3}Lu(BO{sub 3}){sub 3} (BLuB), Y{sub 2}SiO{sub 5} (YSO), Ca{sub 2}Al{sub 2}SiO{sub 7} (CAS) and SrY{sub 4}(SiO{sub 4}){sub 3}O (SYS). The {sup 2}F{sub 7/2} splitting is particularly large in these materials and favourable to a quasi-three-level laser operating scheme. Calculations performed using the point charge electrostatic model for these compounds and using a consistent set of effective atomic charges confirm the experimental results. This should permit to use this model in a predictive approach. (author)

  19. The influence of critical current density of Bi-2212 superconductors by defects after Yb-doping

    Science.gov (United States)

    Lu, Tianni; Zhang, Cuiping; Guo, Shengwu; Wu, Yifang; Li, Chengshan; Zhou, Lian

    2015-12-01

    Bi2Sr2Ca1-xYbxCu2O8+δ (Bi-2212) single crystals with x = 0.000, 0.005, 0.010 and 0.020 have been prepared by self-flux method. The influences of Yb doping on the formation of the dislocations in the lattice structures, as well as the related current carrying capability are investigated. Due to the SQUID measurement and the Bean model calculation, the maximum critical current density (Jc) is obtained when the Yb doping content is x = 0.010, though the Tc and the carrier concentration are not in the optimal region. Based on the HRTEM analyses of the Ca-O and Cu-O2 layers, the optimal dislocation density in the Cu-O2 layers is deduced according to the number of the dislocations per unit area. Besides, the sizes of the dislocations also prove the effectiveness of Yb substitution on the enhancement of the current carrying capability in Bi-2212 single crystals.

  20. Unidirectional dissipative soliton operation in an all-normal-dispersion Yb-doped fiber laser without an isolator.

    Science.gov (United States)

    Li, Daojing; Shen, Deyuan; Li, Lei; Chen, Hao; Tang, Dingyuan; Zhao, Luming

    2015-09-10

    We demonstrate self-started unidirectional dissipative soliton operation and noise-like pulse operation in an all-normal-dispersion bidirectional Yb-doped fiber laser mode-locked by nonlinear polarization rotation. The laser works unidirectionally once mode-locking is achieved due to the cavity directional nonlinearity asymmetry along with the nonlinear polarization rotation mode-locking mechanism. PMID:26368963

  1. Unidirectional dissipative soliton operation in an-normal-dispersion bidirectional Yb-doped fiber laser without an isolator

    CERN Document Server

    Li, Daojing; Li, Lei; Chen, Hao; Tang, Dingyuan; Zhao, Luming

    2015-01-01

    We demonstrate self-started unidirectional dissipative soliton operation and noise-like pulse operation in an all-normal-dispersion bidirectional Yb-doped fiber laser mode-locked by nonlinear polarization rotation. The laser works unidirectional once mode locking was achieved due to the cavity directional nonlinearity asymmetry along with the nonlinear polarization rotation mode locking mechanism.

  2. All-normal-dispersion multi-wavelength dissipative soliton Yb-doped fiber laser

    International Nuclear Information System (INIS)

    We propose and demonstrate an all-normal-dispersion multi-wavelength dissipative soliton Yb-doped fiber laser with a periodic birefringence fiber filter, for the first time to our best knowledge. Numerical simulations show that single-, dual-, and multi-wavelength dissipative solitons can be generated under appropriate filter bandwidth and saturation power. Under a certain filter bandwidth, the generated wavelength number of multi-wavelength mode-locked dissipative solitons is related to the saturation power, decreasing with increasing saturation power. The maximal and minimal attainable wavelength spacing of multi-wavelength dissipative solitons are also investigated, which are 21 nm and 4.6 nm, respectively, according to our simulations. Furthermore, the generation of multi-wavelength dissipative solitons has been verified by experiments. Dual- and three-wavelength dissipative solitons with a wavelength spacing of 16.4 nm have been achieved. (letter)

  3. Hybrid femtosecond fiber laser outcrossing Er-doped fiber and Yb-doped fiber

    Science.gov (United States)

    Kim, Yunseok; Park, Sanguk; Kim, Seung-Woo

    2014-07-01

    A hybridized scheme of a fiber femtosecond pulse laser was devised with the aim of grafting the frequency comb of an Er-doped fiber oscillator, stabilized around a 1.550 μm center wavelength, onto the 1.0 μm emission range of an Yb-doped fiber amplifier. Test results showed that the frequency comb is successfully transferred to a new 1.034 μm center wavelength with a spectral bandwidth of 21 nm, upholding an original frequency stability of 3.71 × 10-13 at 10 s averaging. This work demonstrates the feasibility of outcrossing different kinds of fibers to shift the spectral range of the frequency comb over a large operating span without loss of stability.

  4. Recent developments in polycrystalline oxide fiber laser materials: production of Yb-doped polycrystalline YAG fiber

    Science.gov (United States)

    Lee, HeeDong; Keller, Kristin; Sirn, Brian; Parthasarathy, Triplicane; Cheng, Michael; Hopkins, Frank K.

    2011-09-01

    Laser quality, polycrystalline oxide fibers offer significant advantages over state-of-the-art silica fiber for high energy lasers. Advanced ceramic processing technology, along with a novel powder production process, has potential to produce oxide fibers with an outstanding optical quality for use in the fiber laser applications. The production of contaminant-free green fibers with a high packing density, as well as uniform packing distribution, is a key factor in obtaining laserquality fibers. High quality green fibers are dependent on the powder quality combined with the appropriate slurry formulation. These two fundamental technologies were successfully developed at UES, and used to produce Yb-doped yttrium aluminum garnet (YAG) fibers with high optical quality, high chemical purity, and suitable core diameters down to 20-30 microns.

  5. Sintering and optical quality of highly transparent yb-doped yttrium lanthanum oxide ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Maxim; Zayats, Sergey [Institute of Electrophysics UrB of RAS, Amundsen st 106, 620016 Ekaterinburg (Russian Federation); Kopylov, Yury; Kravchenko, Valery [Institute of Radioengineering and Electronics named after V.A. Kotelnikov, RAS, Vvedensky Sq. 1, 141120 Fryazino, Moscow region (Russian Federation)

    2013-06-15

    To produce highly transparent Yb-doped yttrium lanthanum oxide (Yb{sup 3+}:(La{sub x}Y{sub 1-x}){sub 2}O{sub 3}) ceramics two original technologies were used: laser synthesis of nanopowder and pulsed magnetic compacting. Sintering of the compacts in vacuum 3 x 10{sup -4} Pa at 1600-1700 C during 13 hours led to transparent ceramics fabrication. The ceramics with relative density higher than 99.99% and grain size about 40 {mu}m were fabricated. Full transmittance of 1.8 mm thick Yb{sub 0,11}La{sub 0,23}Y{sub 1,66}O{sub 3} ceramics reaches 82.5% rate at 800 nm. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Q-Switched Large-Mode-Area Yb-Doped Fibre Laser Using GaAs as Saturable Absorber

    Institute of Scientific and Technical Information of China (English)

    FU Sheng-Gui; GUO Zhan-Cheng; SI Li-Bin; ZHAO Ying; YUAN Shu-Zhong; DONG Xiao-Yi

    2007-01-01

    A passive Q-switched large-mode-area Yb-doped fibre laser is demonstrated using a GaAs wafer as the saturable absorber. A high Yb doping concentration double-clad fibre with a core diameter of 30 μm and a numerical aperture of 0.07 is used to increase the laser gain volume, permitting greater energy storage and higher output power than conventional fibres. The maximum average output power is 7.2 W at 1080nm wavelength, with the shortest pulse duration of 580ns and the highest peak power of 161 W when the laser is pumped with a 25 W diode laser operating at 976 nm. The repetition rate increases with the pump power linearly and the highest repetition rate of 77kHz is obtained in the experiment.

  7. Superconductivity in Yb-doped BaFe{sub 2}As{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Chen, S.C. [Department of Physics, National Chung Cheng University, Ming-Hsiung, Chia-Yi 62199, Taiwan, ROC (China); Lee, W.H., E-mail: phywhl@ccu.edu.tw [Department of Physics, National Chung Cheng University, Ming-Hsiung, Chia-Yi 62199, Taiwan, ROC (China); Lan, M.D. [Department of Physics, National Chung Hsing University, Taichung, Taiwan, ROC (China)

    2015-02-15

    Highlights: • Single crystal of (Ba{sub 1−x}Yb{sub x})Fe{sub 2}As{sub 2} (x = 0–0.2) has been grown. • The grown crystals have pure tetragonal ThCr{sub 2}Si{sub 2}-type structure. • (Ba{sub 1−x}Yb{sub x})Fe{sub 2}As{sub 2} (0.05 ≦ x ≦ 0.15) showed a T{sub c,onset} 18–20 K. - Abstract: We report the discovery of superconductivity in Yb-doped BaFe{sub 2}As{sub 2}. Single-crystal specimens of (Ba{sub 1−x}Yb{sub x})Fe{sub 2}As{sub 2} (x = 0–0.2) were grown by using FeAs flux and a slow-cooling method. The superconducting transition temperature for the crystals was determined by dc magnetic susceptibility measurements with a commercial SQUID magnetometer. A clear phase transition from paramagnetic to perfect diamagnetic state was observed around 18–20 K for the samples with nominal composition (Ba{sub 1−x}Yb{sub x})Fe{sub 2}As{sub 2} (0.05 ≦ x ≦ 0.15)

  8. Structural characterization and EXAFS wavelet analysis of Yb doped ZnO by wet chemistry route

    Energy Technology Data Exchange (ETDEWEB)

    Otal, Eugenio H., E-mail: eugenio.otal@citedef.gob.ar [Division of Porous Materials, UNIDEF, CITEDEF, CONICET, S.J.B de la Salle 4397, Villa Martelli (B1603ALO), Buenos Aires (Argentina); Laboratory for Materials Science and Technology, FRSC-UTN, Av. Inmigrantes 555, Río Gallegos 9400 (Argentina); Sileo, Elsa [INQUIMAE, Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina); Aguirre, Myriam H. [Dept. of Physics Condensed Matter, University of Zaragoza (Spain); Laboratory of Advanced Microscopy (LMA), Institute of Nanoscience of Aragón (INA), University of Zaragoza (Spain); Fabregas, Ismael O. [Division of Porous Materials, UNIDEF, CITEDEF, CONICET, S.J.B de la Salle 4397, Villa Martelli (B1603ALO), Buenos Aires (Argentina); Kim, Manuela [Division of Porous Materials, UNIDEF, CITEDEF, CONICET, S.J.B de la Salle 4397, Villa Martelli (B1603ALO), Buenos Aires (Argentina); Laboratory for Materials Science and Technology, FRSC-UTN, Av. Inmigrantes 555, Río Gallegos 9400 (Argentina)

    2015-02-15

    Highlights: • Optical and electrical properties of ZnO are influenced by lanthanide doping. • Optical and electrical properties of ZnO are influenced by lanthanide positioning. • Yb is incorporated in the O{sub h} sites of the wurtzite structure. • There is not Yb{sub 2}O{sub 3} clustering or segregation for treatments below 800 °C. - Abstract: Lanthanide doped ZnO are interesting materials for optical and electrical applications. The wide band gap of this semiconductor makes it transparent in the visible range (E{sub gap} = 3.2 eV), allowing a sharp emission from intra shell transition from the lanthanides. From the electrical side, ZnO is a widely used material in varistors and its electrical properties can be tailored by the inclusion of lanthanides. Both applications are influenced by the location of the lanthanides, grain boundaries or lattice inclusion. Yb doped ZnO samples obtained by wet chemistry route were annealed at different temperatures and characterized by Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Rietveld refinement of XRD data, and X-ray Absorption Fine Structure (XAFS). These techniques allowed to follow the changes occurred in the matrix and the Yb environment. The use of the Cauchy continuous wavelet transform allowed identifying a second coordination shell composed of Zn atoms, supporting the observations from XRD Rietveld refinement and XAFS fittings. The information obtained confirmed the incorporation of Yb in O{sub h} sites of the wurtzite structure without Yb{sub 2}O{sub 3} clustering in the lattice.

  9. Mode-locked Yb-doped fiber laser emitting broadband pulses at ultra-low repetition rates

    CERN Document Server

    Bowen, Patrick; Provo, Richard; Harvey, John D; Broderick, Neil G R

    2016-01-01

    We report on an environmentally stable, Yb-doped, all-normal dispersion, mode-locked fibre laser that is capable of creating broadband pulses with ultra-low repetition rates. Specifically, through careful positioning of fibre sections in an all-PM-fibre cavity mode-locked with a nonlinear amplifying loop mirror, we achieve stable pulse trains with repetition rates as low as 506 kHz. The pulses have several nanojules of energy and are compressible down to ultrashort (< 500 fs) durations.

  10. Multiple Dissipative Solitons in a Long-Cavity Normal-Dispersion Mode-Locked Yb-Doped Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    ZHAO Guang-Zhen; XIAO Xiao-Sheng; MEI Jia-Wei; YANG Chang-Xi

    2012-01-01

    Transitional operations of multiple dissipative solitons in a long-cavity normal-dispersion Yb-doped fiber laser are experimentally investigated.Multiple dissipative solitons,including a stable soliton pair and a soliton triplet are observed by increasing the pump power or adjusting the polarization controllers.Two main boundaries of the stable asymmetric soliton and oscillating soliton are found between steady mode-locking.Moreover,multiple dissipative solitons with greater quantities of solitons are observed with pump power increasing.The experimental results agree well with a previous numerical study of multiple dissipative solitons.

  11. Yb-doped SnTe semimetal thin films deposited by thermal evaporation: Structural, electrical, and thermoelectric properties

    Science.gov (United States)

    Hmood, A.; Kadhim, A.; Hassam, H. A.

    2014-12-01

    Sn monochalcogenide and Yb-doped Sn1-xYbxTe (0.0 ⩾ x ⩽ 0.1) semimetals, which are known for their usefulness as efficient thermoelectric (TE) materials, were prepared by solid-state microwave technique. Polycrystalline thin films of Sn1-xYbxTe were deposited onto clean glass substrates by using vacuum evaporation technique at 10-6 bar. The structures of the polycrystalline thin films were examined by X-ray diffraction patterns. A rock salt structure was observed. Grain size increased with increasing Yb content but not according to a sequence. The morphology of the nanosheet structures for these thin films was determined by field emission scanning electron microscopy. TE properties were measured at a temperature range of 298-523 K. The carrier concentrations of the films were determined by Hall effect measurements at 300 K.

  12. Gain and Noise Figure of a Double-Pass Waveguide Amplifier Based on Er/Yb-Doped Phosphate Glass

    Institute of Scientific and Technical Information of China (English)

    JIN Guo-Liang; SHAO Gong-Wang; Mu Huan; HU Li-Li; LI Qu

    2005-01-01

    @@ A waveguide amplifier is fabricated by Ag+-Na+ two-step ion exchange on Er/Yb-doped phosphate glass. Thespectroscopic performance of glass and the properties of channel waveguide are characterized. A double-passconfiguration is adopted to measure the gain and noise figure (NF) of the waveguide amplifier, and the comparisonof gain and NF for the single and double-pass configuration of the waveguide amplifier is presented. The resultsshow that the double-pass configuration can make the gain increase from 8.8dB (net gain 2.2dB/cm) of thesingle-pass one to 14.6dB (net gain 3.65dB/cm) for small input power at 1534nm, and the NF are all lower than5.5dB for both the configurations.

  13. MoS2 saturable absorber for single frequency oscillation of highly Yb-doped fiber laser

    Institute of Scientific and Technical Information of China (English)

    Baole Lu; Limei Yuan; Xinyuan Qi; Lei Hou; Bo Sun; Pan Fu; Jintao Bai

    2016-01-01

    In this Letter,a single-frequency fiber laser using a molybdenum disulfide (MoS2) thin film as a saturable absorber is demonstrated.We use a short length of highly Yb-doped fiber as the gain medium and a fiber ferrule with MoS2 film adhered to it by index matching gel (IMG) that acts as the saturable absorber.The saturable absorber can be used to discriminate and select the single longitudinal modes.The maximum output power of the single-frequency fiber laser is 15.3 mW at a pump power of 130 mW and the slope efficiency is 15.3%.The optical signal-to-noise ratio and the laser linewidths are ~60 dB and 5.89 kHz,respectively.

  14. Pulsed laser deposition and thermoelectric properties of In-and Yb-doped CoSb3 skutterudite thin films

    KAUST Repository

    Sarath Kumar, S. R.

    2011-07-29

    In-and Yb-doped CoSb3 thin films were prepared by pulsed laser deposition. Process optimization studies revealed that a very narrow process window exists for the growth of single-phase skutterudite films. The electrical conductivity and Seebeck coefficient measured in the temperature range 300-700 K revealed an irreversible change on the first heating cycle in argon ambient, which is attributed to the enhanced surface roughness of the films or trace secondary phases. A power factor of 0.68 W m-1 K-1 was obtained at ∼700 K, which is nearly six times lower than that of bulk samples. This difference is attributed to grain boundary scattering that causes a drop in film conductivity. Copyright © Materials Research Society 2011.

  15. Three-dimensional modeling of CPA to the multimillijoule level in tapered Yb-doped fibers for coherent combining systems.

    Science.gov (United States)

    Andrianov, Alexey; Anashkina, Elena; Kim, Arkady; Meyerov, Iosif; Lebedev, Sergey; Sergeev, Alexander; Mourou, Gerard

    2014-11-17

    We developed a three-dimensional numerical model of Large-Mode-Area chirped pulse fiber amplifiers which includes nonlinear beam propagation in nonuniform multimode waveguides as well as gain spectrum dynamics in quasi-three-level active ions. We used our model in tapered Yb-doped fiber amplifiers and showed that single-mode propagation is maintained along the taper even in the presence of strong Kerr nonlinearity and saturated gain, allowing extraction of up to 3 mJ of output energy in 1 ns pulse. Energy scaling and its limitation as well as the influence of fiber taper bending and core irregularities on the amplifier performance were studied. We also investigated numerically the capabilities for compression and coherent combining of up to 36 perturbed amplifying channels and showed more than 70% combining efficiency, even with up to 11% of high-order modes in individual channels. PMID:25402067

  16. High order harmonic mode-locking in an all-normal-dispersion Yb-doped fiber laser with a graphene oxide saturable absorber

    Science.gov (United States)

    Huang, S. S.; Wang, Y. G.; Yan, P. G.; Zhang, G. L.; Zhao, J. Q.; Li, H. Q.; Lin, R. Y.

    2014-01-01

    A high order passive harmonic mode-locking (HML) Yb-doped all-normal-dispersion fiber laser based on a graphene oxide saturable absorber has been experimentally demonstrated. For two different pump powers and different polarization states of the laser cavity, lower order and higher order HML have been achieved. The highest 30th-order harmonic (31.86 MHz) was achieved with subnanosecond pulse duration; this is transitional from a bunched multipulse state.

  17. Gain-switched laser diode seeded Yb-doped fiber amplifier delivering 11-ps pulses at repetition rates up to 40-MHz

    CERN Document Server

    Ryser, Manuel; Pilz, Soenke; Burn, Andreas; Romano, Valerio

    2014-01-01

    Here, we demonstrate all-fiber direct amplification of 11 picosecond pulses from a gain-switched laser diode at 1063nm. The diode was driven at a repetition rate of 40MHz and delivered 13$\\mu$W of fiber-coupled average output power. For the low output pulse energy of 0.33pJ we have designed a multi-stage core pumped preamplifier based on single clad Yb-doped fibers in order to keep the contribution of undesired amplified spontaneous emission as low as possible and to minimize temporal and spectral broadening. After the preamplifier we reduced the 40MHz repetition rate to 1MHz using a fiber coupled pulse-picker. The final amplification was done with a cladding pumped Yb-doped large mode area fiber and a subsequent Yb-doped rod-type fiber. With our setup we achieved amplification of 72dBs to an output pulse energy of 5.7$\\mu$J, pulse duration of 11ps and peak power of >0.6MW.

  18. Terahertz radiation using log-spiral-based low-temperature-grown InGaAs photoconductive antenna pumped by mode-locked Yb-doped fiber laser.

    Science.gov (United States)

    Kong, Moon Sik; Kim, Ji Su; Han, Sang Pil; Kim, Namje; Moon, Kiwon; Park, Kyung Hyun; Jeon, Min Yong

    2016-04-01

    We demonstrate a terahertz (THz) radiation using log-spiral-based low-temperature-grown (LTG) InGaAs photoconductive antenna (PCA) modules and a passively mode-locked 1030 nm Yb-doped fiber laser. The passively mode-locked Yb-doped fiber laser is easily implemented with nonlinear polarization rotation in the normal dispersion using a 10-nm spectral filter. The laser generates over 250 mW of the average output power with positively chirped 1.58 ps pulses, which are dechirped to 127 fs pulses using a pulse compressor outside the laser cavity. In order to obtain THz radiation, a home-made emitter and receiver constructed from log-spiral-based LTG InGaAs PCA modules were used to generate and detect THz signals, respectively. We successfully achieved absorption lines over 1.5 THz for water vapor in free space. Therefore, we confirm that a mode-locked Yb-doped fiber laser has the potential to be used as an optical source to generate THZ waves. PMID:27136997

  19. Electrically tunable fiber-integrated Yb-doped laser covering 74 nm based on a fiber Bragg grating array

    Science.gov (United States)

    Tiess, T.; Rothhardt, M.; Chojetzki, C.; Jäger, M.; Bartelt, H.

    2015-03-01

    Fiber lasers provide the foundation to combine an excellent beam quality in single mode operation with a robust and highly efficient design. Based on fiber-integrated configurations, they are employed in many different applications ranging from industry over research to medical technology. However, there is lots of potential to approach even new fields of applications e.g. in spectroscopy based on tunable systems with an adjustable emission wavelength. We present a novel tuning concept for pulsed fiber-integrated laser systems using an array of fiber Bragg gratings (FBGs) as discrete spectral filter. Based on stacking many standard FBGs, the bandwidth and filter properties are easy to scale by increasing the number of gratings allowing huge tuning ranges as well as tailored tuning characteristics. In this work, we demonstrate the potential of this electrically controlled tuning concept. Using an Ytterbium (Yb)-doped fiber laser, we investigate the general tuning characteristics. With variable pulse durations in the nanosecond regime, we demonstrate high signal contrast (~45 dB), excellent wavelength stability and narrow linewidth (knowledge, is the largest bandwidth reported based on a monolithic filter design.

  20. A controllable noise-like operation regime in a Yb-doped dispersion-mapped fiber ring laser

    Science.gov (United States)

    Zaytsev, A. K.; Lin, C. H.; You, Y. J.; Tsai, F. H.; Wang, C. L.; Pan, C. L.

    2013-04-01

    We report the generation of tunable high-energy noise-like pulses with a super-broadband spectrum from a Yb-doped dispersion-mapped fiber ring laser. Self-starting noise-like operation can be maintained over a relatively large range of pumping powers (4-13 W). The corresponding output power varies from 0.1 to 1.45 W. The maximum 3 dB spectral bandwidth of the noise-like pulses is about 48.2 nm while the output energy is as high as 47 nJ, limited by optical damage of the components. The central wavelength of the noise-like pulses can be tuned easily over ˜12 nm. The bandwidth and duration of the generated wave packets can also be controlled. The use of a negative dispersion-delay line and spectral filter are found to be important for generating such high-power noise-like operation. Experimental results are in good agreement with theoretical simulations.

  1. Flexibly controllable multi-pulse mode-locked MOPA Yb-doped fiber laser in all normal dispersion regime

    Science.gov (United States)

    Bu, Chenxi; Wang, Chinhua

    2013-09-01

    A Controllable, high energy, all normal dispersion (ANDi), passively mode-locked Yb-doped fiber laser is demonstrated with a Master Oscillator Power-Amplifier (MOPA) structure. The mode-locking is achieved by nonlinear polarization evolution (NPE). different types of laser pulse are achieved from fundamental mode-locked (FML) single pulse to twin pulse and then to harmonically mode-locked (HML) pulses (the maximum order is 7 times) by adjusting quarter-wave plates (QWPS) and a half-wave plate (HWP) in our system. Using a cascaded long-period fiber grating as the spectral filter, the center wavelength of our laser is fixed at 1034nm.The repetition frequency rate of the FML pulse is 1.53MHz with a pulse width of 817ps. The maximum average energy is 450 mW and the maximum pulse energy of FML single pulse is 294 nJ. Besides, the 517nm green laser output is also achieved by using a LiB3O5 (LBO) crystal as the frequency doubling crystal. The maximum average of the green pulse is 4.71mW.

  2. Lattice dynamics and substrate-dependent transport properties of (In, Yb)-doped CoSb3 skutterudite thin films

    KAUST Repository

    Sarath Kumar, S. R.

    2011-10-24

    Lattice dynamics, low-temperature electrical transport, and high-temperature thermoelectric properties of (In, Yb)-doped CoSb3thin films on different substrates are reported. Pulsed laser deposition under optimized conditions yielded single-phase polycrystalline skutterudite films. Raman spectroscopy studies suggested that In and Yb dopants occupy the cage sites in the skutterudite lattice. Low-temperature electrical transport studies revealed the n-type semiconducting nature of the films with extrinsic and intrinsic conduction mechanisms, in sharp contrast to the degenerate nature reported for identical bulk samples. Calculations yielded a direct bandgap close to 50 meV with no evidence of an indirect gap. The carrier concentration of the films was identical to that reported for the bulk and increased with temperature beyond 250 K. The higher resistivity exhibited is attributed to the enhanced grain boundary scattering in films with a high concentration of grains. The maximum power factor of ∼0.68 W m−1 K−1 obtained at 660 K for the film on glass is found to be nearly four times smaller compared to that reported for the bulk. The observed difference in the power factors of the films on different substrates is explained on the basis of the diffusion of oxygen from the substrates and the formation of highly conducting CoSb2 phase upon the oxidation of CoSb3.

  3. Density-functional study on the robust ferromagnetism in rare-earth element Yb-doped SnO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kai-Cheng, E-mail: kczhang@yeah.net [College of Mathematics and Physics, Bohai University, Jinzhou 121013 (China); Li, Yong-Feng [Key Laboratory of Integrated Exploitation of Bayan Obo Multi-Metal ResourcesInner Mongolia University of Science and Technology, Baotou 014010 (China); School of Mathematics, Physics and Biological Engineering, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Liu, Yong [State Key Laboratory of Metastable Materials Science and Technology and College of Science, Yanshan University, Qinhuangdao, Hebei 066004 (China); Chi, Feng [College of Engineering, Bohai University, Jinzhou 121013 (China)

    2014-06-01

    So far, little has been known about the ferromagnetism induced by p–f hybridization. We investigate the magnetic properties of Yb-doped SnO{sub 2} by first-principles calculations. We find that the doped system favors the ferromagnetic state and a room-temperature ferromagnetism can be expected in it. The origin of ferromagnetism can be attributed to the p–f hybridization between Yb impurity and its surrounding oxygen atoms. The formation energy of defect complex is calculated and the magnetic mediation of intrinsic vacancies is studied. Our results reveal that the formation energy of the defect complex with Sn vacancy is about 7.3 eV lower in energy than that with oxygen vacancy. This means Sn vacancy is much easier to form than oxygen vacancy in the presence of Yb substitution. The ferromagnetism of the doped system is greatly enhanced in the presence of Sn vacancies. - Highlights: • Room-temperature ferromagnetism can be expected in Yb-doped SnO{sub 2}. • The origin of ferromagnetism can be attributed to the p–f hybridization between Yb and O atoms. • Oxygen vacancies are much hard to form and contribute little to the ferromagnetism. • Sn vacancies are easy to form under oxygen-rich condition and stabilize the ferromagnetism effectively.

  4. Characteristics of Soliton Evolution in the Wave-Breaking-Free Regime in a Passively Mode-Locked Yb-Doped Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    WU Ge; TIAN Xiao-Jian; GAO Bo; SHAN Jiang-Dong; RU Yu-Xing

    2011-01-01

    @@ We focus on several aspects concerning the numerical simulation of a passively mode-locked Yb-doped fiber laser by a non-distributed model.The characteristics of soliton evolution in a wave-breaking-free regime are numerically investigated with the split-step Fourier method.Based on the model,a parabolic-shaped soliton with a nearlylinear chirp and bound soliton pairs are obtained by controlling the intra-cavity average dispersion of the fiber laser.A phenomenon is observed that by keeping the system parameters unchanged,linearly chirped parabolic soliton and bound soliton pairs are attainable under different initial conditions in the transient region between these two kinds of solitons.%We focus on several aspects concerning the numerical simulation of a passively mode-locked Yb-doped fiber laser by a non-distributed model. The characteristics of soliton evolution in a wave-breaking-free regime are numerically investigated with the split-step Fourier method. Based on the model, a parabolic-shaped soliton with a nearly linear chirp and bound soliton pairs are obtained by controlling the intra-cavity average dispersion of the fiber laser. A phenomenon is observed that by keeping the system parameters unchanged, linearly chirped parabolic soliton and bound soliton pairs are attainable under different initial conditions in the transient region between these two kinds of solitons.

  5. Second Harmonic Generation Using an All-Fiber Q-Switched Yb-Doped Fiber Laser and MgO:c-PPLN

    Directory of Open Access Journals (Sweden)

    Yi Gan

    2008-01-01

    Full Text Available We have experimentally demonstrated an efficient all-fiber passively Q-switched Yb-doped fiber laser with Samarium doped fiber as a saturable absorber. Average output power of 3.4 W at a repetition rate of 250 kHz and a pulse width of 1.1 microseconds was obtained at a pump power of 9.0 W. By using this fiber laser system and an MgO-doped congruent periodically poled lithium niobate (MgO:c-PPLN, second harmonic generation (SHG output at 532 nm was achieved at room temperature. The conversion efficiency is around 4.2% which agrees well with the theoretical simulation.

  6. Intervalence charge transfer luminescence: Interplay between anomalous and 5d − 4f emissions in Yb-doped fluorite-type crystals

    Energy Technology Data Exchange (ETDEWEB)

    Barandiarán, Zoila, E-mail: zoila.barandiaran@uam.es; Seijo, Luis [Departamento de Química, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Instituto Universitario de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid (Spain)

    2014-12-21

    In this paper, we report the existence of intervalence charge transfer (IVCT) luminescence in Yb-doped fluorite-type crystals associated with Yb{sup 2+}–Yb{sup 3+} mixed valence pairs. By means of embedded cluster, wave function theory ab initio calculations, we show that the widely studied, very broad band, anomalous emission of Yb{sup 2+}-doped CaF{sub 2} and SrF{sub 2}, usually associated with impurity-trapped excitons, is, rather, an IVCT luminescence associated with Yb{sup 2+}–Yb{sup 3+} mixed valence pairs. The IVCT luminescence is very efficiently excited by a two-photon upconversion mechanism where each photon provokes the same strong 4f{sup 14}–1A{sub 1g}→ 4f{sup 13}({sup 2}F{sub 7/2})5de{sub g}–1T{sub 1u} absorption in the Yb{sup 2+} part of the pair: the first one, from the pair ground state; the second one, from an excited state of the pair whose Yb{sup 3+} moiety is in the higher 4f{sup 13}({sup 2}F{sub 5/2}) multiplet. The Yb{sup 2+}–Yb{sup 3+} → Yb{sup 3+}–Yb{sup 2+} IVCT emission consists of an Yb{sup 2+} 5de{sub g} → Yb{sup 3+} 4f{sub 7/2} charge transfer accompanied by a 4f{sub 7/2} → 4f{sub 5/2} deexcitation within the Yb{sup 2+} 4f{sup 13} subshell: [{sup 2}F{sub 5/2}5de{sub g},{sup 2}F{sub 7/2}] → [{sup 2}F{sub 7/2},4f{sup 14}]. The IVCT vertical transition leaves the oxidized and reduced moieties of the pair after electron transfer very far from their equilibrium structures; this explains the unexpectedly large band width of the emission band and its low peak energy, because the large reorganization energies are subtracted from the normal emission. The IVCT energy diagrams resulting from the quantum mechanical calculations explain the different luminescent properties of Yb-doped CaF{sub 2}, SrF{sub 2}, BaF{sub 2}, and SrCl{sub 2}: the presence of IVCT luminescence in Yb-doped CaF{sub 2} and SrF{sub 2}; its coexistence with regular 5d-4f emission in SrF{sub 2}; its absence in BaF{sub 2} and SrCl{sub 2}; the quenching of

  7. Sintering of transparent Yb-doped Lu{sub 2}O{sub 3} ceramics using nanopowder produced by laser ablation method

    Energy Technology Data Exchange (ETDEWEB)

    Kijko, V.S. [Ural Federal University named after the first President of Russia B.N. Yeltsin, Mira St. 19, Ekaterinburg 620002 (Russian Federation); Maksimov, R.N., E-mail: romanmaksimov@e1.ru [Ural Federal University named after the first President of Russia B.N. Yeltsin, Mira St. 19, Ekaterinburg 620002 (Russian Federation); Institute of Electrophysics UB RAS, Amundsen St.106, Ekaterinburg 620016 (Russian Federation); Shitov, V.A. [Institute of Electrophysics UB RAS, Amundsen St.106, Ekaterinburg 620016 (Russian Federation); Demakov, S.L.; Yurovskikh, A.S. [Ural Federal University named after the first President of Russia B.N. Yeltsin, Mira St. 19, Ekaterinburg 620002 (Russian Federation)

    2015-09-15

    Highlights: • Yb:Lu{sub 2}O{sub 3} nanoparticles synthesized by laser ablation method were investigated. • Transparent Yb:Lu{sub 2}O{sub 3} ceramics were fabricated via vacuum and spark plasma sintering. • Highest transmittance was 79.3% at 1080 nm for vacuum sintered Yb:Lu{sub 2}O{sub 3} sample. - Abstract: Transparent Yb-doped Lu{sub 2}O{sub 3} ceramic samples were fabricated via conventional vacuum and spark plasma sintering. Nanoparticles synthesized by laser ablation method were used as starting material. The morphology and phase evolution of the nanopowder were studied by transmission electron microscopy, simultaneous thermal analysis and X-ray diffraction. The obtained nanoparticles exhibited the monoclinic phase and were fully converted into the main cubic phase after calcination at 1100 °C for 1 h. Conventional vacuum sintering of Yb:Lu{sub 2}O{sub 3} powder compact at 1780 °C for 20 h resulted in a fully-dense ceramics with an average grain size of 1.6 μm and optical transmittance of 79.3% at 1080 nm. Spark plasma sintering of the calcined Yb:Lu{sub 2}O{sub 3} nanoparticles at 1450 °C and 15 kN for 40 min led to a 0.2 μm-grained ceramics exhibiting an optical transmittance of 75.6% at 1080 nm.

  8. All-normal dispersion passively mode-locked Yb-doped fiber laser using MoS2-PVA saturable absorber

    Science.gov (United States)

    Sathiyan, S.; Velmurugan, V.; Senthilnathan, K.; Babu, P. Ramesh; Sivabalan, S.

    2016-05-01

    We demonstrate the generation of a dissipative soliton in an all-normal dispersion ytterbium (Yb)-doped fiber laser using few-layer molybdenum disulfide (MoS2) as a saturable absorber. The saturable absorber is prepared by mixing few-layer MoS2 solution with polyvinyl alcohol (PVA) to form a free-standing composite film. The modulation depth and saturation intensity of the MoS2-PVA film are 11% and 5.86 MW cm-2, respectively. By incorporating the MoS2 saturable absorber in the fiber laser cavity, the mode-locked pulses are generated with a pulse width of 1.55 ns and a 3 dB spectral bandwidth of 0.9 nm centered at 1037.5 nm. The fundamental repetition rate and the average power are measured as 15.43 MHz and 1.5 mW, respectively. These results reveal the feasibility of deploying liquid-phase exfoliated few-layer MoS2 nanosheets for dissipative soliton generation in the near-IR region.

  9. 980-nm all-fiber mode-locked Yb-doped phosphate fiber oscillator based on semiconductor saturable absorber mirror and its amplifier

    Science.gov (United States)

    Li, Ping-Xue; Yao, Yi-Fei; Chi, Jun-Jie; Hu, Hao-Wei; Zhang, Guang-Ju; Liang, Bo-Xing; Zhang, Meng-Meng; Ma, Chun-Mei; Su, Ning

    2016-08-01

    A 980-nm semiconductor saturable absorber mirror (SESAM) mode-locked Yb-doped phosphate fiber laser is demonstrated by using an all-fiber linear cavity configuration. Two different kinds of cavity lengths are introduced into the oscillator to obtain a robust and stable mode-locked seed source. When the cavity length is chosen to be 6 m, the oscillator generates an average output power of 3.5 mW and a pulse width of 76.27 ps with a repetition rate of 17.08 MHz. As the cavity length is optimized to short, 4.4-mW maximum output power and 61.15-ps pulse width are produced at a repetition rate of 20.96 MHz. The output spectrum is centered at 980 nm with a narrow spectral bandwidth of 0.13 nm. In the experiment, no undesired amplified spontaneous emission (ASE) nor harmful oscillation around 1030 nm is observed. Moreover, through a two-stage all-fiber-integrated amplifier, an output power of 740 mW is generated with a pulse width of 200 ps. Project supported by the National Natural Science Foundation of China (Grant No. 61205047).

  10. 超长腔碳纳米管锁模多波长掺镱光纤激光器∗%Ultra-long cavity multi-wavelength Yb-doped fiber laser mode-locked by carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    王玉宝; 齐晓辉; 沈阳; 姚繄蕾; 徐志敬; 潘玉寨

    2015-01-01

    We demonstrate an ultra-long cavity multi-wavelength Yb-doped fiber laser mode-locked by carbon nanotubes. The total length of the fiber laser is 1021.2 m. The different regimes of noise-like soliton and soliton rain mode-locking with the multi-wavelength operation are experimentally obtained with a repetition rate of 199.8 kHz. The higher output power and pulse energy from the soliton rain are measured to be 40.3 mW and 201.5 nJ, respectively, with a pulse width of about 102.5 ns.

  11. Photoexcitation of Yb-doped aluminosilicate fibers at 250 nm: evidence for excitation transfer from oxygen deficiency centers to Yb{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, C. G. [Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801 (United States); Present address: Laser and Optics Research Center, USAF Academy, Colorado Springs, Colorado 80840 (United States); Keister, K. E.; Dragic, P. D.; Eden, J. G. [Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801 (United States); Croteau, A. [INO, 2740 Einstein Street, Quebec City, Quebec G1P 4S4 (Canada)

    2010-10-15

    Emission spectra in the {approx}240-1100 nm wavelength region as well as the temporally resolved decay of Yb{sup 3+} and point defect spontaneous emission have been recorded when aluminosilicate optical fibers doped with Yb are irradiated with {approx}160 fs laser pulses having a central wavelength of {approx}250 nm (({Dirac_h}/2{pi}){omega}=5 eV). Photoexcitation of the fibers in this region of the deep ultraviolet (UV) provides access simultaneously to the Type II Si oxygen deficiency center (ODC), the non-bridging oxygen hole center (NBOHC: an oxygen-excess defect), and the Ge ODC. Emission from all of these defects in the ultraviolet and/or visible is observed, as is intense fluorescence at 976 nm from Yb{sup 3+}. Absorption measurements conducted in the {approx}230-265 nm region with a sequence of UV light-emitting diodes reveal a continuum peaking at {approx}248 nm and having a spectral width of {approx}18 nm (FWHM), confirming that the 250 nm laser pump is photoexciting predominantly the ODC. The temporal histories of the optically active defect and rare earth ion emission waveforms, in combination with time-integrated spectra, suggest that the Si ODC(II) triplet state directly excites Yb{sup 3+} as well as at least one other intrinsic defect in the silica network. Prolonged exposure of the Yb-doped fibers to 250 nm radiation yields increased Yb{sup 3+}, NBOHC, and Si ODC(II) singlet emission which is accompanied by a decline in Si ODC(II) triplet fluorescence, thus reinforcing the conclusion--drawn on the basis of luminescence decay constants--that the triplet state of Si ODC(II) is the immediate precursor to the NBOHC and is partially responsible for Yb ion emission at 976 nm. This conclusion is consistent with the observation that exposure of fiber to 5 eV radiation slightly suppresses ODC absorption in the {approx}240-255 nm region while simultaneously introducing an absorption continuum extending from 260 nm to below 235 nm (({Dirac_h}/2{pi

  12. 波长可调节全正色散掺镱锁模光纤激光器的放大特性%Amplification of tunable ANDi Yb- doped mode-locked fiber laser

    Institute of Scientific and Technical Information of China (English)

    华弋; 肖晓晟

    2014-01-01

    高功率,波长可调超短脉冲光源具有重大的应用价值。采用掺镱光纤放大的全正色散锁模光纤激光器能够满足以上优质光源的要求,并且结构紧凑。通过实验全面探索了波长可调节全正色散锁模光纤激光器的放大特性。分析了小信号增益系数随着信号光波长的变化。发现最大增益出现在波长为1030 nm附近,并且增益随着信号光波长的增大而减小,这是由于掺镱光纤的增益谱特性决定的。也分析了增益系数随泵浦光功率的变化,观察增益饱和现象和放大自发辐射噪声。也讨论了种子脉冲在放大器中的时域与频域畸变。发现脉冲因为群速度色散而轻微展宽,频谱因为自相位调制也会发生轻微展宽。%Ultrashort pulse source with high energy and tunable wavelength is highly demanded for a lot of applications. Amplified all-normal-dispersion(ANDi) mode-locked fiber laser with gain medium of Yb-doped fiber is a compact and excellent source that fulfills those requirements. In this paper, amplification of tunable ANDi Yb- doped mode-locked fiber lasers was experimentally investigated. The gain versus signal wavelength was analyzed. It was found that the maximum gain was obtained near 1 030 nm and the gain decreased as wavelength increased, due to the gain spectrum of Yb- doped fiber. The gain versus pump power was also investigated. Gain saturation and the effect of ASE noise on gain were observed. The spectral and temporal distortions of pulse seed induced by fiber amplification were discussed. The pulse was broadened slightlydue to dispersion. The spectrum was distorted by ASE noise and limited gain bandwidth. If the gain is large and the power of amplified signal is high, the spectrum will be broadened by the effect of self-phase modulation(SPM).

  13. High power, picosecond green laser based on a frequency-doubled, all-fiber, narrow-bandwidth, linearly polarized, Yb-doped fiber laser

    Science.gov (United States)

    Tian, Wenyan; Isyanova, Yelena; Stegeman, Robert; Huang, Ye; Chieffo, Logan R.; Moulton, Peter F.

    2016-03-01

    We report on the development of an all-fiber, 68-kW-peak-power, 16-ps-pulse-width, narrow-bandwidth, linearly polarized, 1064-nm fiber laser suitable for high-power, picosecond-pulse-width, green-light generation. Our 1064-nm fiber laser delivered an average power of up to 110 W at a repetition of 100- MHz in a narrow bandwidth, with minimal nonlinear distortion. We developed a high-power, picosecond green source at 532 nm through use of single-pass frequency-doubling of our 1064-nm fiber laser in lithium triborate (LBO). Using a 15-mm long LBO crystal, we have generated 30 W of average power in the second harmonic with 73-W of fundamental average power, for a conversion efficiency of 41%.

  14. 30 W Cr:LiSrAlF 6 flashlamp-pumped pulsed laser.

    Science.gov (United States)

    Samad, Ricardo Elgul; Baldochi, Sonia Licia; Calvo Nogueira, Gesse Eduardo; Vieira, Nilson Dias

    2007-01-01

    We report the performance of a flashlamp-pumped Cr:LiSrAlF(6) (Cr:LiSAF) laser developed and built by us. The pumping cavity incorporates filters that select the flashlamps' emission spectrum to match the absorption bands of the gain medium, allowing control of the amount of nonradiactive decay heat contribution of the optical cycle, minimizing thermal effects on the laser operation. The laser generated 2 J pulses at 15 Hz, resulting in 30 W of average power, the highest power extracted from a Cr:LiSAF rod laser to our knowledge. We were able to conclude that the laser efficiency is affected by resonator configuration changes due to thermal lens effects, and not to thermal quenching of the Cr:LiSAF luminescence. PMID:17167580

  15. Effect of Sintering Temperature on Microstructure, Chemical Stability and Electrical Properties of Transition Metal or Yb-Doped BaZr0.1Ce0.7Y0.1M0.1O3-δ (M = Fe, Ni, Co and Yb

    Directory of Open Access Journals (Sweden)

    Behzad eMirfakhraei

    2014-03-01

    Full Text Available Perovskite-type BaZr0.1Ce0.7Y0.1M0.1O3-δ (M = Fe, Ni, Co and Yb (BZCY-M oxides were synthesized using the conventional solid-state reaction method at 1350-1550 oC in air in order to investigate the effect of dopants on sintering, crystal structure, chemical stability under CO2 and H2S, and electrical transport properties. The formation of the single-phase perovskite-type structure with an orthorhombic space group Imam was confirmed by Rietveld refinement using powder X-ray diffraction (PXRD for the Fe, Co, Ni and Yb-doped samples. The BZCY-Co and BZCY-Ni oxides show a total electrical conductivity of 0.01 and 8 × 10-3 Scm-1 at 600 oC in wet H2 with an activation energy of 0.36 and 0.41 eV, respectively. Scanning electron microscopy (SEM and energy-dispersive X-ray analysis (EDX revealed Ba and Co rich secondary phase at the grain-boundaries, which may explain the enhancement in the total conductivity of the BZCY-Co. However, ex-solution of Ni at higher sintering temperatures, especially at 1550 oC, decreases the total conductivity of the BZCY-Ni material. The Co and Ni dopants act as a sintering aid and form dense pellets at a lower sintering temperature of 1250 oC. The Fe, Co and Ni-doped BZCY-M samples synthesized at 1350 oC show stability in 30 ppm H2S/H2 at 800 oC, and increasing the firing temperature to 1550 oC, enhanced the chemical stability in CO2 / N2 (1: 2 at 25-900 oC. The BZCY-Co and Ni compounds with high conductivity in wet H2 could be considered as possible anodes for intermediate temperature solid oxide fuel cells (IT-SOFCs.

  16. A new vision of photodarkening in Yb-doped fibers

    OpenAIRE

    Peretti, Romain; Jurdyc, Anne-Marie; Gonnet, Cedric

    2012-01-01

    International audience Yb3+-doped fiber is one of the most promising hosts for high-power fiber lasers [1]. However, in the late 1990s, photodarkening effect, i.e., the creation of color centers induced by light, was observed and reported [2]. Like in other rare-earth-doped materials, a broad visible and near infrared absorption band appears during laser operation, which strongly lowers the laser efficiency. We have shown how thulium impurities, present at the parts-per-billion weights (pp...

  17. High power radially-polarized Yb-doped fiber laser

    OpenAIRE

    Lin, Di; Daniel, J. M. O.; Gecevičius, M.; Beresna, M; Kazansky, P. G.; Clarkson, W. A.

    2014-01-01

    A simple technique for directly generating a radially-polarized output beam from an ytterbium-doped fiber laser using an intracavity spatially-variant waveplate is reported. The laser yielded 32W of output with a corresponding slope efficiency of 65.8% in a radially-polarised beam with beam propagation factor ~2.1 and polarization purity >95%

  18. Linearly polarized intracavity passive Q-switched Yb-doped photonic crystal fibre laser

    Indian Academy of Sciences (India)

    Usha Chakravarty; Antony Kuruvilla; Rajpal Singh; B N Upadhyay; K S Bindra; S M Oak

    2014-02-01

    In this paper we report linearly polarized high average power passive Q-switched ytterbium-doped photonic crystal fibre laser with a Cr4+:YAG crystal as a saturable absorber. An average output power of 9.4 W with pulse duration of 64 ns and pulse repetition rate of 57.4 kHz with a slope efficiency of 52% was achieved. Measured polarization extinction ratio (PER) of the Q-switched laser output was 10.5 dB.

  19. Monolithic Highly Stable Yb-Doped Femtosecond Fiber Lasers for Applications in Practical Biophotonics

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Lægsgaard, Jesper; Turchinovich, Dmitry

    2012-01-01

    Operational and environmental stability of ultrafast laser systems is critical for their applications in practical biophotonics. Mode-locked fiber lasers show great promise in applications such as supercontinuum sources or multiphoton microscopy systems. Recently, substantial progress has been made...... in the development of all-fiber nonlinear-optical laser control schemes, which resulted in the demonstration of highly stable monolithic, i.e., not containing any free-space elements, lasers with direct fiber-end delivery of femtosecond pulses. This paper provides an overview of the progress in the development...... of such all-fiber mode-locked lasers based on Yb-fiber as gain medium, operating at the wavelength around 1 $\\mu$m, and delivering femtosecond pulses reaching tens of nanojoules of energy....

  20. Demonstration of a homogeneous Yb-doped core fully aperiodic large-pitch fiber laser.

    Science.gov (United States)

    Dauliat, Romain; Benoît, Aurélien; Darwich, Dia; Jamier, Raphaël; Kobelke, Jens; Grimm, Stephan; Schuster, Kay; Roy, Philippe

    2016-08-10

    The first demonstration of a 40 μm core homogeneously ytterbium-doped fully aperiodic large-pitch fiber laser, to the best of our knowledge, is reported here. In this concept, the amplification of unwanted high-order modes is prevented by means of an aperiodic inner-cladding structure, while the core and inner-cladding material has a higher refractive index than pure silica. In a laser configuration, up to 252 W of extracted power, together with an optical-to-optical efficiency of 63% with respect to the incident pump power, have been achieved. While an average M2 of 1.4 was measured, the emitted power becomes temporally unstable when exceeding 95 W, owing to the occurrence of modal instabilities. PMID:27534463

  1. Electrical and microstructural properties of Yb-doped CeO2

    Directory of Open Access Journals (Sweden)

    B. Matović

    2014-06-01

    Full Text Available Nanopowdered Ce1−xYbxO2−δ solid solutions (0 ≤ x ≤ 0.2 were synthesized by a self-propagating room temperature synthesis. XRD and SEM were used to study the properties of these materials as well as the Yb solubility in CeO2 lattice. Results showed that all the obtained powders were solid solutions with a fluorite-type crystal structure and with nanometric particle size. The average size of Ce1−xYbxO2−δ particles was approximately 3 nm. Electrochemical impedance spectroscopy for the sintered pellets depicted that it was possible to separate Rbulk and Rgb in the temperature interval of 550–800 °C. The activation energy for the bulk conduction was 1.03 eV and for grain boundary conduction was 1.14 eV. Grain boundary resistivity dominates over the other resistivities. These measurements confirmed that Yb3+-doped CeO2 material had a potential as electrolyte for intermediate-temperature solid oxide fuel cell applications.

  2. Radiation effects on Yb- and Er/Yb-doped optical fibers: A micro-luminescence study

    Energy Technology Data Exchange (ETDEWEB)

    Tortech, B.; Ouerdane, Y.; Meunier, J. P.; Boukenter, A. [Univ St Etienne, CNRS, UMR 5516, Lab Hubert Curien, F-42000 St Etienne (France); Girard, S. [CEA Bruyeres le Chatel, DIF, 91 (France); Robin, T.; Cadier, B.; Crochet, P. [iXFiber SAS, F-22300 Lannion (France)

    2009-07-15

    The integration of rare-earth doped optical fibers as part of fiber-based systems in space implies the development of waveguides tolerant to the radiation levels associated with the space missions. Erbium (Er)- or Ytterbium/Erbium (Yb/Er)-doped fibers have been shown to be very sensitive to ionizing radiations. Radiations lead to a strong increase of the fiber attenuation around the pump and amplified signal wavelengths. In this paper, we investigate by confocal luminescence microscopy the radiation-induced spectroscopic changes on prototype Yb- or Yb/Er-doped optical fibers. The set of tested fibers allows us to provide new insights into the relative influence of the P, Al doping on the radiation responses of their silica-based host matrix and on the transitions between the energy states of rare-earth ions. (authors)

  3. Tm-Yb Doped Optical Fiber Performance with Variation of Host-Glass Composition

    Directory of Open Access Journals (Sweden)

    Anirban Dhar

    2014-01-01

    Full Text Available The fabrication process of Thulium-Ytterbium doped optical fiber comprising different host glass through the Modified Chemical Vapor Deposition (MCVD coupled with solution doping technique is presented. The material and optical performance of different fibers are compared with special emphasis on their lasing efficiency for 2 µm application.

  4. Tm-Yb Doped Optical Fiber Performance with Variation of Host-Glass Composition

    OpenAIRE

    Anirban Dhar; Atasi Pal; Shyamal Das; Ranjan Sen

    2014-01-01

    The fabrication process of Thulium-Ytterbium doped optical fiber comprising different host glass through the Modified Chemical Vapor Deposition (MCVD) coupled with solution doping technique is presented. The material and optical performance of different fibers are compared with special emphasis on their lasing efficiency for 2 µm application.

  5. Luminance Conversion Property of Er and Yb Doped KZnF3 Nanocrystal Synthesized by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Weidong Lai

    2015-01-01

    Full Text Available In order to make full use of exposure energy, one feasible way is to modify the luminance of crystal by rare earth doping technique. KZnF3:Er3+ and KZnF3:Er3+/Yb3+ nanocrystals of uniform cuboid perovskite type morphology, with average diameter of 130 nm, has been synthesized by hydrothermal method. When Yb3+ ions were codoped with Er3+, absorption peak at 970 nm has been heightened and widened, and the photon absorption cross section increased. The common xenon lamp exposure cannot initiate obvious nonlinear phenomenon of the doped Er3+ and Yb3+, and exposing at 245 nm only excites the fluorescence around 395 nm. Contrarily, under high power IR exposure at 980 nm, obvious upconversion photoluminescence (PL has been observed due to the two-photon process. The PL mechanism of the doped Er3+ ion in KZnF3:Er3+/Yb3+ nanocrystals is confirmed. Furthermore, Yb3+ codoped as sensitizer has modified the PL intensity of Er3+ from green light range to red range, and the primary channel is changed from 4S3/2(Er3+ → 4I15/2(Er3+ of only Er3+ doped KZnF3 nanocrystal to 4F9/2(Er3+ → 4I15/2(Er3+ of Er3+/Yb3+ codoped sample. With exposure energy increasing, such primary transition channel after two-photon excitation is unchanged.

  6. Spatially selective Er/Yb-doped CaF{sub 2} crystal formation by CO{sub 2} laser exposure

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-Seon; Lee, Jin-Ho; Lim, Ki-Soo, E-mail: kslim@chungbuk.ac.kr

    2015-04-15

    Highlights: • Oxyfluoride glass–ceramics containing CaF{sub 2} nanocrystals doped with Er{sup 3+} and Yb{sup 3+} ions were formed on the glass surface by CO{sub 2} laser and a heat gun exposure. • Most of Er and Yb ions were distributed inside CaF{sub 2} nanocrystals and fluorine loss was observed in the EDS element maps. • IR-to-VIS upconversion emission efficiency of laser annealed glass ceramics was much increased and compared with that of the furnace-annealed glass ceramics. • Distributed volume of the glass ceramics were estimated by a confocal fluorescence microscope imaging. - Abstract: We report the glass–ceramic precipitation on the oxyfluoride glass surface by spatially selective annealing with a CO{sub 2} laser and a heat gun exposure. X-ray diffraction analysis showed the formation of major CaF{sub 2} and miner Ca{sub 2}SiO{sub 4} nanoparticles. We observed ∼100 nm nanoparticle aggregation by tunneling electron microscopy and element distribution in glass and crystal phases. Spatial distribution of glass ceramics near the glass surface was probed by confocal fluorescence microscope by using much enhanced emission from the Er ions in the laser-treated area. Strong emissions at 365 nm excitation and visible up-conversion emissions at 980 nm excitation also indicated well incorporation of Er and Yb ions into a crystalline environment.

  7. Single-mode amplification in Yb-doped rod-type photonic crystal fibers for high brilliance lasers

    DEFF Research Database (Denmark)

    Poli, F.; Lægsgaard, Jesper; Passaro, D.;

    2009-01-01

    higher-order mode (HOM), stressing the difference between their spatial distributions, with respect to the uniform refractive index core. In the present analysis a rod-type PCF with a 19-missing air-hole core, whose radius is 30 mum, has been considered. Initially, a PCF step-index model has been applied...... a forward-pumped configuration....

  8. Strong broad green UV-excited photoluminescence in rare earth (RE = Ce, Eu, Dy, Er, Yb) doped barium zirconate

    Energy Technology Data Exchange (ETDEWEB)

    Borja-Urby, R. [Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (EMANA), Centro de Investigaciones en Optica A. C., Leon, Gto. 37150 (Mexico); Diaz-Torres, L.A., E-mail: ditlacio@cio.mx [Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (EMANA), Centro de Investigaciones en Optica A. C., Leon, Gto. 37150 (Mexico); Salas, P. [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, A.P. 1-1010, Queretaro, Qro. 76000 (Mexico); Angeles-Chavez, C. [Instituto Mexicano del Petroleo, Ciudad de Mexico, D. F. 07730 (Mexico); Meza, O. [Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (EMANA), Centro de Investigaciones en Optica A. C., Leon, Gto. 37150 (Mexico)

    2011-10-25

    Highlights: > Trivalent rare earth (RE) substitution on Zr{sup 4+} sites in BaZrO{sub 3} lead to band gap narrowing. > RE substitution lead to enhanced blue-green intrinsic emission of nanocrystalline BaZrO{sub 3} > Blue-green hue of BaZrO3:RE depends on RE dopant and excitation UV wavelength > BaZrO3: Dy{sup 3+} PL chromatic coordinates correspond to pure white color coordinates of CIE 1931 model - Abstract: The wet synthesis hydrothermal method at 100 deg. C was used to elaborate barium zirconate (BaZrO{sub 3}) unpurified with 0.5 mol% of different rare earth ions (RE = Yb, Er, Dy, Eu, Ce). Morphological, structural and UV-photoluminescence properties depend on the substituted rare earth ionic radii. While the crystalline structure of RE doped BaZrO{sub 3} remains as a cubic perovskite for all substituted RE ions, its band gap changes between 4.65 and 4.93 eV. Under 267 nm excitation the intrinsic green photoluminescence of the as synthesized BaZrO{sub 3}: RE samples is considerably improved by the substitution on RE ions. For 1000 deg. C annealed samples, under 267 nm, the photoluminescence is dominated by the intrinsic BZO emission. It is interesting to notice that Dy{sup 3+}, Er{sup 3+} and Yb{sup 3+} doped samples present whitish emissions that might be useful for white light generation under 267 nm excitation. CIE color coordinates are reported for all samples.

  9. Thermal effect-resilient design of large mode area double-cladding Yb-doped photonic crystal fibers

    DEFF Research Database (Denmark)

    Coscelli, Enrico; Poli, Federica; Johansen, Mette Marie;

    2013-01-01

    on the finite-element method has been used to calculate the guided modes of the fibers operating at high power levels. The results demonstrate that resonant structures added to the fiber cross-section can be exploited to provide efficient suppression of high-order modes with a good resilience to...

  10. Spatially selective Er/Yb-doped CaF2 crystal formation by CO2 laser exposure

    International Nuclear Information System (INIS)

    Highlights: • Oxyfluoride glass–ceramics containing CaF2 nanocrystals doped with Er3+ and Yb3+ ions were formed on the glass surface by CO2 laser and a heat gun exposure. • Most of Er and Yb ions were distributed inside CaF2 nanocrystals and fluorine loss was observed in the EDS element maps. • IR-to-VIS upconversion emission efficiency of laser annealed glass ceramics was much increased and compared with that of the furnace-annealed glass ceramics. • Distributed volume of the glass ceramics were estimated by a confocal fluorescence microscope imaging. - Abstract: We report the glass–ceramic precipitation on the oxyfluoride glass surface by spatially selective annealing with a CO2 laser and a heat gun exposure. X-ray diffraction analysis showed the formation of major CaF2 and miner Ca2SiO4 nanoparticles. We observed ∼100 nm nanoparticle aggregation by tunneling electron microscopy and element distribution in glass and crystal phases. Spatial distribution of glass ceramics near the glass surface was probed by confocal fluorescence microscope by using much enhanced emission from the Er ions in the laser-treated area. Strong emissions at 365 nm excitation and visible up-conversion emissions at 980 nm excitation also indicated well incorporation of Er and Yb ions into a crystalline environment

  11. Efficient intracavity frequency doubling of an Yb-doped fiber laser using an internal resonant enhancement cavity

    OpenAIRE

    Cieslak, R.; Sahu, J.K.; Clarkson, W. A.

    2010-01-01

    We describe a simple approach for efficient generation of visible light in high-power continuous-wave fiber lasers via second harmonic generation in an internal resonant cavity. Preliminary results for a cladding-pumped Yb fiber laser are presented.

  12. Thermo-Optical Tuning of Whispering Gallery Modes in Er:Yb Doped Glass Microspheres to Arbitrary Probe Wavelengths

    CERN Document Server

    Watkins, Amy; Chormaic, Síle Nic

    2012-01-01

    We present experimental results on an all-optical, thermally-assisted technique for broad range tuning of microsphere cavity resonance modes to arbitrary probe wavelengths. An Er:Yb co-doped phosphate glass (Schott IOG-2) microsphere is pumped at 978 nm via the supporting stem and the heat generated by absorption of the pump light expands the cavity and changes the refractive index. This is a robust tuning method that decouples the pump from the probe and allows fine tuning of the microsphere's whispering gallery modes. Pump/probe experiments were performed to demonstrate thermo-optical tuning to specific probe wavelengths, including the 5S1/2 F = 3 to 5P3/2 F' = 4 laser cooling transition of 85Rb. This is of particular interest for cavity QED-type experiments, while the broad tuning range achievable is useful for integrated photonic devices, including sensors and modulators.

  13. Superconductivity at 31.3 K in Yb-doped La(O/F)FeAs superconductors

    Indian Academy of Sciences (India)

    J Prakash; S J Singh; S Patnaik; A K Ganguli

    2010-01-01

    The effect of ytterbium substitution at the lanthanum site on the superconducting properties of La1-YbO0.8F0.2FeAs ( = 0.10, 0.20 and 0.30) oxypnictides has been investigated. Powder X-ray diffraction studies show the presence of Yb2O3 and LaOF as secondary phases. The superconducting transition temperature (c) of 31.3 (± 0.05) K has been observed in = 0.1 composition which is the maximum c so far in the La(O/F)FeAs superconductor family at ambient pressure. Further increase in leads to suppression and broadening of superconducting transition. The resistive transition curves under different magnetic fields were investigated, leading to determination of upper critical field c2 () of this new superconductor. The value of c2 at zero temperature is estimated to be about 46 T corresponding to coherence length ∼ 27 Å.

  14. Design of 30W Power Supply for LED Driving Based on FAN7554%基于FAN7554的30W LED驱动电源设计

    Institute of Scientific and Technical Information of China (English)

    高家宝; 刘堃

    2015-01-01

    A principle block diagram of power supply for LED driving based on PWM controller IC was presented. Using the PWM IC FAN7554 as the main microchip to design a fly-back LED drive that is designed with an output power of 120W, an output voltage 33V and an output current 0.9A. The circuit can supply drive power for a LED array with 30 tubes with the power of 1 W by using 10 in series and 3 in parallel. And introduces the operation principles of the designed circuit. The power supply for LED driving of this design has passed a series of related electric tests and it has got some satisfactory results in the actual operation, capable of entering the low power LED lighting market, and can be a reference for high performance, low cost low-power LED power supply design.%提出了一种基于PWM(脉冲宽度调制)控制芯片的小功率LED驱动电源的原理框架。采用FAN7554芯片作为主控制器,设计了一款输出功率达30W的反激式LED驱动电源,其输出电压为33V,输出电流为0.9A,可为30只功率为1W的LED管采用10串3并混联方式组成的LED阵列提供驱动电源,并分析所设计LED驱动电源的基本原理。该LED驱动电源经过一系列的电气测试,并在实际运行中得到比较满意的结果,具有进入小功率LED照明市场的能力,且对设计高性能、低成本的小功率LED驱动电源具有一定的指导意义。

  15. Metal-to-metal charge transfer between dopant and host ions: Photoconductivity of Yb-doped CaF{sub 2} and SrF{sub 2} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Barandiarán, Zoila, E-mail: zoila.barandiaran@uam.es; Seijo, Luis [Departamento de Química, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Instituto Universitario de Ciencia de Materiales Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid (Spain)

    2015-10-14

    Dopant-to-host electron transfer is calculated using ab initio wavefunction-based embedded cluster methods for Yb/Ca pairs in CaF{sub 2} and Yb/Sr pairs in SrF{sub 2} crystals to investigate the mechanism of photoconductivity. The results show that, in these crystals, dopant-to-host electron transfer is a two-photon process mediated by the 4f{sup N−1}5d excited states of Y b{sup 2+}: these are reached by the first photon excitation; then, they absorb the second photon, which provokes the Y b{sup 2+} + Ca{sup 2+} (Sr{sup 2+}) → Y b{sup 3+} + Ca{sup +} (Sr{sup +}) electron phototransfer. This mechanism applies to all the observed Y b{sup 2+} 4f–5d absorption bands with the exception of the first one: Electron transfer cannot occur at the first band wavelengths in CaF{sub 2}:Y b{sup 2+} because the Y b{sup 3+}–Ca{sup +} states are not reached by the two-photon absorption. In contrast, Yb-to-host electron transfer is possible in SrF{sub 2}:Y b{sup 2+} at the wavelengths of the first 4f–5d absorption band, but the mechanism is different from that described above: first, the two-photon excitation process occurs within the Y b{sup 2+} active center, then, non-radiative Yb-to-Sr electron transfer can occur. All of these features allow to interpret consistently available photoconductivity experiments in these materials, including the modulation of the photoconductivity by the absorption spectrum, the differences in photoconductivity thresholds observed in both hosts, and the peculiar photosensitivity observed in the SrF{sub 2} host, associated with the lowest 4f–5d band.

  16. Stimulated Brillouin Scattering Enhancement Factor Improvement in a 11.6-GHz-Linewidth 1.5-kW Yb-Doped Fiber Amplifier

    Science.gov (United States)

    Guang-Bo, Liu; Yi-Feng, Yang; Jian-Hua, Wang; Ye, Zheng; Xiao-Long, Chen; Kai, Liu; Chun, Zhao; Yun-Feng, Qi; Bing, He; Jun, Zhou

    2016-07-01

    Not Available Supported by the National Natural Science Foundation of China under Grant Nos U1330134, 61308024 and 11174305, the National High-Technology Research and Development Program of China under Grant No 2014AA041901, and the Shanghai Natural Science Foundation under Grant No 11ZR1441400.

  17. High-power near-infrared linearly-polarized supercontinuum generation in a polarization-maintaining Yb-doped fiber amplifier.

    Science.gov (United States)

    Zhang, Bin; Jin, Aijun; Ma, Pengfei; Chen, Shengping; Hou, Jing

    2015-11-01

    We report an all-fiber linearly-polarized (LP) supercontinuum (SC) source with high average power generated in a polarization-maintaining (PM) master-oscillation power-amplifier (MOPA). The experimental configuration comprises an LP picosecond pulsed laser and three PM Yd-doped fiber amplifiers (YDFA). The output has the average power of 124.8 W with the spectrum covering from 850 to 1900 nm. The measured polarization extinction ratio (PER) of the whole SC source is about 85% which verifies the SC an LP source. This work is, to our best knowledge, the highest output average power of an LP SC source that ever reported. The influence of PM fiber splicing method on the LP SC property is investigated by splicing the PM fibers with slow axis parallel or perpendicularly aligned, and also an LP SC with low output power is demonstrated. PMID:26561136

  18. Over three-octave spanning supercontinuum generated in a fluoride fiber pumped by Er & Er:Yb-doped and Tm-doped fiber amplifiers

    Science.gov (United States)

    Swiderski, Jacek; Michalska, Maria

    2013-11-01

    We demonstrate broadband 0.9-3.6 μm supercontinuum (SC) generation with 0.66 W of output power, using a single-mode fluoride (ZBLAN) fiber pumped by 1.55 μm nanosecond pulses amplified in a cascade of fiber amplifiers. Expanding the pump source by adding an additional amplification section based on thulium-doped fibers, the long-wavelength edge of the spectrum was shifted to ~4 μm and was limited by intrinsic losses of the used nonlinear fiber. For this cases, the average SC power as high as 288 mW was recorded, of which 266 mW (92%), 167 mW (58%) and 60 mW (21%) corresponds to wavelengths longer than 2 μm, 3 μm and 3.6 μm. The performance of the SC sources is described.

  19. Multi-mJ mid-infrared kHz OPCPA and Yb-doped pump lasers for tabletop coherent soft x-ray generation

    International Nuclear Information System (INIS)

    We present our recent progress on the development of a mid-infrared (mid-IR), multi-mJ, kHz optical parametric chirped-pulse amplification (OPCPA) system, pumped by a homebuilt picosecond cryogenic Yb:YAG chirped-pulse amplifier, and its application to soft x-ray high-order harmonic generation. The cryogenic Yb:YAG laser operating at 1 kHz repetition rate delivers 42 mJ, 17 ps, 1.03 μm pulses to pump the OPCPA system. Efficient second and fourth harmonic generations from the Yb:YAG system are demonstrated, which provide the pumping capability for OPCPA at various wavelengths. The mid-IR OPCPA system produces 2.6 mJ, 39 fs, 2.1 μm pulses with good beam quality (M 2 = ∼1.5) at 1 kHz repetition rate. The output pulses of the OPCPA are used to generate high-order harmonics in both gas cell and hollow-core fiber targets. A photon flux of ∼2 × 108 photon/s/1% bandwidth at 160 eV in Ar is measured while the cutoff is 190 eV. The direct measurements of the photon flux from x-ray photodiodes have confirmed the generation of water-window soft x-ray photons with a flux ∼106 photon/s/1% bandwidth at 330 eV in Ne. The demonstrated OPCPA and Yb:YAG pump laser technologies provide an excellent platform of energy and power scalable few-cycle mid-IR sources that are suitable for high-flux tabletop coherent soft x-ray generation. (paper)

  20. Polarized spectra calculation and continuous wave laser operation of Yb-doped disordered Ca3La2(BO3)4 crystal

    Science.gov (United States)

    Wang, Yeqing; Chen, Aixi; You, Zhenyu; Tu, Chaoyang

    2015-12-01

    A notable disorder crystal Yb:Ca3La2(BO3)4 crystal with Yb3+ ion doping concentration of 10 at.% was grown by the Czochralski method. The polarized absorption, polarized emission, and polarized gain cross sections were systematically calculated. The laser operations were investigated with Yb:Ca3La2(BO3)4 crystals cut along the a, b, and c crystallographic axes. The highest output power of 3.88 W was obtained by using the b-cut Yb:Ca3La2(BO3)4 crystal, with a slope efficiency of 62%. Additionally, it was confirmed that the output laser spectra were largely dependent on the output coupler.

  1. Fabrication of 16 W all-normal-dispersion mode-locked Yb-doped rod-type fiber laser with large-mode area

    Institute of Scientific and Technical Information of China (English)

    吕国; 滕浩; 王立娜; 王睿; 王军利; 魏志义

    2015-01-01

    A mode-locked ytterbium-doped rod-type fiber laser with 85 µm core diameter is developed based on the nonlinear polarization evolution in an all-normal-dispersion ring cavity, in which a uniaxial birefringent plate is used as the spectral filter. Average power up to 16 W is obtained at the repetition rate of 58 MHz, and the pulse duration is compressed to 182 fs with a grating-pair compressor. The output laser pulses show very good beam quality and power stability.

  2. Investigation on repetition rate and pulse duration influences on ablation efficiency of metals using a high average power Yb-doped ultrafast laser

    Directory of Open Access Journals (Sweden)

    Lopez J.

    2013-11-01

    Full Text Available Ultrafast lasers provide an outstanding processing quality but their main drawback is the low removal rate per pulse compared to longer pulses. This limitation could be overcome by increasing both average power and repetition rate. In this paper, we report on the influence of high repetition rate and pulse duration on both ablation efficiency and processing quality on metals. All trials have been performed with a single tunable ultrafast laser (350 fs to 10ps.

  3. High-energy femtosecond Yb-doped all-fiber monolithic chirped-pulse amplifier at repetition rate of 1 MHz

    Science.gov (United States)

    Lv, Zhi-Guo; Teng, Hao; Wang, Li-Na; Wang, Jun-Li; Wei, Zhi-Yi

    2016-09-01

    A high-energy femtosecond all ytterbium fiber amplifier based on a chirped-pulse amplification (CPA) technique at a repetition rate of 1 MHz seeded by a dispersion-management mode-locked picosecond broadband oscillator is studied. We find that the compressed pulse duration is dependent on the amplified energy, the pulse duration of 804 fs corresponds to the maximum amplified energy of 10.5 μJ, while the shortest pulse duration of 424 fs corresponds to the amplified energy of 6.75 μJ. The measured energy fluctuation is approximately 0.46% root mean square (RMS) over 2 h. The low-cost femtosecond fiber laser source with super-stability will be widely used in industrial micromachines, medical therapy, and scientific studies. Project supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China (Grant No. 2012BAC23B03), the National Key Basic Research Program of China (Grant No. 2013CB922401), and the National Natural Science Foundation of China (Grant No. 11474002).

  4. High-power near-infrared linearly-polarized supercontinuum generation in a polarization-maintaining Yb-doped fiber amplifier.

    Science.gov (United States)

    Zhang, Bin; Jin, Aijun; Ma, Pengfei; Chen, Shengping; Hou, Jing

    2015-11-01

    We report an all-fiber linearly-polarized (LP) supercontinuum (SC) source with high average power generated in a polarization-maintaining (PM) master-oscillation power-amplifier (MOPA). The experimental configuration comprises an LP picosecond pulsed laser and three PM Yd-doped fiber amplifiers (YDFA). The output has the average power of 124.8 W with the spectrum covering from 850 to 1900 nm. The measured polarization extinction ratio (PER) of the whole SC source is about 85% which verifies the SC an LP source. This work is, to our best knowledge, the highest output average power of an LP SC source that ever reported. The influence of PM fiber splicing method on the LP SC property is investigated by splicing the PM fibers with slow axis parallel or perpendicularly aligned, and also an LP SC with low output power is demonstrated.

  5. 可调谐Yb光纤激光器LBO倍频特性理论研究%Theoretical analysis of frequency doubling of wavelength-tunable Yb-doped fiber lasers with LBO crystal

    Institute of Scientific and Technical Information of China (English)

    戴明; 柳强; 闫平; 巩马理

    2006-01-01

    针对大信号高斯光束聚焦情况,对平面波耦合波方程进行了改进;利用改进后的耦合波方程,分析了LBO晶体对掺Yb光纤激光整个发射光谱的腔外倍频特性.结果显示,利用温度调谐,LBO晶体可以在掺Yb光纤的整个发射光谱内达到非临界相位匹配;随着基频光波长的增加,倍频效率会有小幅度下降,可接收角有小幅度增长,可接收温度宽度和可接收线宽有较大幅度加宽.结果表明,采取非临界相位匹配,并选用较长的基频光波,易于得到理想的倍频效果.

  6. 1.5  kW ytterbium-doped single-transverse-mode, linearly polarized monolithic fiber master oscillator power amplifier.

    Science.gov (United States)

    Huang, Long; Ma, Pengfei; Tao, Rumao; Shi, Chen; Wang, Xiaolin; Zhou, Pu

    2015-04-01

    A linearly polarized monolithic fiber laser based on a master oscillator power amplifier structure with a master oscillator and a one-stage power amplifier is reported. We design a homemade oscillator based on the theory that, in the coiled gain fiber, the higher modes and the polarized mode of the fundamental mode along the fast axis are suppressed effectively because of their obviously higher bend loss than that of the polarized mode of the fundamental mode along the slow axis. The oscillator operates at 1080 nm, launching a 30 W seed laser with a high polarization extinction ratio of 19 dB into the power amplifier via a mode field adapter. The power amplifier utilizes Yb-doped polarization-maintaining fiber of 20/400  μm, which produces nearly diffraction-limited output power of about 1.5 kW with an optical-optical efficiency of 81.5% and a polarization extinction ratio of 13.8 dB. Both the M(x)² factor and the M(y)² factor of the collimated beam are measured to be about 1.2. The spectral width of the output power is broadened approximately linearly, and the full width at half maximum of the spectrum at the maximum output power is about 5.8 nm. It is known as the highest linearly polarized output power to the best of our knowledge. PMID:25967203

  7. Optical channel waveguides in $KY(WO_4)_2:Yb^{3+}$

    NARCIS (Netherlands)

    Borca, C.N.; Romanyuk, Y.E.; Gardillou, F.; Pollnau, M.; Bernal, M.P.; Moretti, P.

    2006-01-01

    First channel waveguide emission from Yb-doped $KY(WO_4)_2$ has been demonstrated. Two different methods have been used to fabricate micron-size active-guiding structures, namely reactive ion etching and ion implantation.

  8. Theoretical analysis of radiation-balanced double clad fiber laser

    Institute of Scientific and Technical Information of China (English)

    CHEN Ji-xin; SUI Zhan; CHEN Fu-shen; LI Ming-zhong; WANG Jian-jun

    2005-01-01

    In this letter,a theoretical model of radiation-balanced double clad fiber laser is presented.The characteristic of the laser with Yb doped double clad fiber is analyzed numerically.It is concluded that high output laser power can be obtained by selecting output coupling mirror with lower reflectivity,improving Yb doped concentration and choosing fiber length. This result can help us to design radiation balanced fiber laser.

  9. All-fiber nonlinearity- and dispersion-managed dissipative soliton nanotube mode-locked laser

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z. [Department of Physics, Bilkent University, 06800 Ankara (Turkey); Nanjing University of Posts and Communications, Nanjing 210003 (China); Popa, D., E-mail: dp387@cam.ac.uk; Wittwer, V. J.; Milana, S.; Hasan, T.; Jiang, Z.; Ferrari, A. C. [Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA (United Kingdom); Ilday, F. Ö. [Department of Physics, Bilkent University, 06800 Ankara (Turkey); Department of Electrical and Electronics Engineering, Bilkent University, 06800 Ankara (Turkey)

    2015-12-14

    We report dissipative soliton generation from an Yb-doped all-fiber nonlinearity- and dispersion-managed nanotube mode-locked laser. A simple all-fiber ring cavity exploits a photonic crystal fiber for both nonlinearity enhancement and dispersion compensation. The laser generates stable dissipative solitons with large linear chirp in the net normal dispersion regime. Pulses that are 8.7 ps long are externally compressed to 118 fs, outperforming current nanotube-based Yb-doped fiber laser designs.

  10. Thermal Effects in High-Power Fiber Amplifiers

    DEFF Research Database (Denmark)

    Hansen, Kristian Rymann; Lægsgaard, Jesper

    2011-01-01

    The effect of temperature gradients in Yb-doped fiber amplifiers is studied numerically. We investigate the dependence of the mode area on the signal power, and compare forward and backward pumping schemes.......The effect of temperature gradients in Yb-doped fiber amplifiers is studied numerically. We investigate the dependence of the mode area on the signal power, and compare forward and backward pumping schemes....

  11. X波段30W固态功率放大模块的设计%Design for 30W X-band Solid State Power Amplifier Module

    Institute of Scientific and Technical Information of China (English)

    程光伟; 闫燕勤

    2014-01-01

    Microwave power amplifier is widely used and indispensable in radar,navigation,communications,satellite earth station,electronic warfare equipment .Introduce a x-band solid-state power amplifier module design process.Through the RF simulation software ADS according to the S parameters of microwave solid state power amplifier module design and optimize bias blocking circuit and matching circuit,power amplifier through synthesis of cascade,power allocation,meet the requirements of design index.%微波功率放大器的应用范围广,在雷达、导航、通信、卫星地面收发站、电子对抗仪器设备中不可或缺。介绍一个 X波段固态功率放大器模块的设计过程,通过 ADS射频仿真软件根据 S参数对微波固态功放模块的偏置隔直电路以及匹配电路进行设计优化,功率放大器经过级联、功率分配合成,达到设计的指标要求。

  12. Ultralow-threshold Yb(3+):SiO(2) glass laser fabricated by the solgel process.

    Science.gov (United States)

    Ostby, Eric P; Yang, Lan; Vahala, Kerry J

    2007-09-15

    A Yb-doped silica microcavity laser on a silicon chip is fabricated from a solgel thin film. The high-Q micro-toroid cavity, which has a finesse of 10,000, is evanescently coupled to an optical fiber taper. We report a threshold of 1.8 microW absorbed power that is, to the best of our knowledge, the lowest published threshold to date for any Yb-doped laser. The effect of Yb(3+) concentration on laser threshold is experimentally quantified. PMID:17873923

  13. Widely and rapidly tunable semiconductor master-oscillator fiber amplifier around 1080 nm

    NARCIS (Netherlands)

    Adhimoolam, Balaji; Klein, Marvin E.; Lindsay, Ian D.; Gross, Petra; Lee, Chris J.; Boller, Klaus-Jochen

    2006-01-01

    We describe the wide and rapid wavelength tuning of a continuous-wave master-oscillator power-amplifier system consisting of a semiconductor-amplifier-based oscillator and an ytterbium (Yb)-doped fiber amplifier. The oscillator utilizes an acoustooptic tunable filter and an intracavity etalon to ach

  14. Growth and characterization of highly Yb3+doped KY(WO4)2 thin layers

    NARCIS (Netherlands)

    Aravazhi, S.; Geskus, D.; Dalfsen, van K.; Günther, D.; Pollnau, M.

    2011-01-01

    Highly Yb-doped, lattice-matched layers of potassium double tungstates with different compositions were grown on undoped KY(WO4)2 substrates. Structural and optical investigations confirmed their high quality. Applications are in high-gain amplifiers and thin-disk lasers.

  15. Femtosecond all-polarization-maintaining fiber laser operating at 1028 nm

    DEFF Research Database (Denmark)

    Olsson, R.K.; Andersen, T.V.; Leick, Lasse;

    2008-01-01

    We present an effective solution for an all-polarization-maintaining modelocked femtosecond fiber laser operating at the central wavelength of 1028 nm. The laser is based on an Yb-doped active fiber. Modelocking is enabled by a semiconductor saturable absorber mirror, and the central wavelength...

  16. Wavelength-swept fiber laser with frequency shifted feedback

    OpenAIRE

    Yun, S. H.; Richardson, D. J.; Culverhouse, D.O.; Kim, B.Y

    1997-01-01

    We report a frequency-shifted, wavelength-swept Er/Yb-doped fiber laser. By matching the intra-cavity filter sweep rate to the frequency shift per round trip controllable, high power (>100mW), cw modeless output over 38m, with

  17. Thermo-optical effects in high-power Ytterbium-doped fiber amplifiers

    DEFF Research Database (Denmark)

    Hansen, Kristian Rymann; Alkeskjold, Thomas Tanggaard; Broeng, Jes;

    2011-01-01

    We investigate the effect of temperature gradients in high-power Yb-doped fiber amplifiers by a numerical beam propagation model, which takes thermal effects into account in a self-consistent way. The thermally induced change in the refractive index of the fiber leads to a thermal lensing effect...

  18. 100W fully-fiberised Ytterbium doped master oscillator power amplifier incorporating adaptive pulse shaping

    OpenAIRE

    Lin, Dejiao; Alam, Shaif-ul; Chen, Kangkang; Malinowski, Andrew; Norman, Steve; Richardson, David

    2009-01-01

    We report a pulsed, fully-fiberised, Yb-doped MOPA with a maximum average output power of 100W. Adaptive pulse shaping was incorporated to reduce the impact of nonlinearities, delivering 2mJ flat-topped pulses with 20kW peak power.

  19. Rare-earth-ion-doped ultra-narrow-linewidth lasers on a silicon chip and applications to intra-laser-cavity optical sensing

    NARCIS (Netherlands)

    Bernhardi, E.H.; Ridder, de R.M.; Wörhoff, K.; Pollnau, M.

    2013-01-01

    We report on diode-pumped distributed-feedback (DFB) and distributed-Bragg-reflector (DBR) channel waveguide lasers in Er-doped and Yb-doped Al2O3 on standard thermally oxidized silicon substrates. Uniform surface-relief Bragg gratings were patterned by laser-interference lithography and etched into

  20. Influences of Yb substitution on the intergrain connections and flux pinning properties of Bi-2212 superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shengnan, E-mail: snzhang@c-nin.com [Superconducting Materials Research Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); Li, Chengshan; Hao, Qingbin [Superconducting Materials Research Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); Lu, Tianni [Superconducting Materials Research Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); College of Materials Science and Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Zhang, Pingxiang [Superconducting Materials Research Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China)

    2015-04-15

    Highlights: • Optimization of intergrain connections has been obtained by Yb doping. • Changes of the grain boundary structures after doping have been observed by HRTEM. • Flux pinning mechanism change with Yb doping has been analyzed and explained. • Improved critical current density has been obtained by proper amount of Yb doping. - Abstract: Polycrystalline bulks Bi{sub 2}Sr{sub 2−x}Yb{sub x}CaCu{sub 2.0}O{sub 8+δ} (Bi-2212) with Yb doping content of x = 0, 0.01, 0.02 and 0.05) were fabricated by solid state sintering process. Bi-2212 precursor powders were synthesized by modified co-precipitation process, and Yb{sub 2}O{sub 3} powders were added into the precursor powders during the calcination process as dopants. The influences of Yb substitution on the lattice parameter, microstructure and related superconducting properties were systematically investigated. The amorphous components within the grain boundaries were observed with HRTEM, which contributed to the formation of weak links. Therefore, both the decreasing number of porosity and better crystallized grain boundary structure after Yb doping obviously enhanced the intergrain connections. Meanwhile, doping of Yb ions into Bi-2212 matrix also contributed to the enhancement of point pining, thus lead to the improvement of in-field critical current density. Based on the enhancements of both intergrain connections and flux pinning properties, improvement of critical current density was obtained with the optimal doping content of x = 0.02.

  1. Andesita Cerro Bola: Nueva unidad vinculada al magmatismo mioceno de la Cordillera de Olivares, San Juan, Argentina (30°35´S; 69°30´O Cerro Bola Andesite: New unit linked to the Miocene magmatism of the Olivares Cordillera, San Juan (30°35' S ; 68°30' W

    Directory of Open Access Journals (Sweden)

    A.F. Wetten

    2005-03-01

    Full Text Available El área de estudio se halla en la zona de Tocota, inmediatamente al este de la Cordillera de Olivares, en el borde oriental de la Cordillera Frontal, provincia de San Juan. En ella se encuentran unidades ígneas y sedimentarias del ciclo gondwánico, las que fueron intruidas y cubiertas en relación discordante por cuerpos subvolcánicos y volcánicos asignados anteriormente al ciclo ándico en sentido amplio, los cuales constituyen el principal objeto del presente estudio. Estos cuerpos han sido mapeados a fin de poder caracterizarlos adecuadamente, en el contexto estratigráfico de la región. Los afloramientos de interés han sido reconocidos en el cerro Bola y alrededores, donde se observan distribuidos irregularmente, cubriendo un área superior a 5 km². Las rocas, de coloración gris clara y composición andesítica - fenoandesítica, presentan estructuras de domo y colada. Estos afloramientos serían correlacionables con la unidad volcánica Pircas (Mioceno, la que aflora al oeste, y conformarían un evento magmático posterior al de pórfidos de diferente composición situados tanto en el arroyo Chita como en el cerro Divisadero. La extensión del área involucrada, la uniformidad litológica, el bajo grado de alteración y una edad radimétrica obtenida por el método K/Ar, fueron considerados para proponer a estas volcanitas como una unidad litoestratigráfica de edad miocena superior, con la denominación de Andesita Cerro Bola.The study area is located in the region of Tocota Creek, close to the Cordillera Olivares, eastern border of the Frontal Range, San Juan province. In this place, igneous and sedimentary units belonging to the Gondwanic cycle, were recognized. These units were intruded and unconformably covered by subvolcanic and volcanic bodies, which were commonly referred to the Tertiary or Andean cycle. The study of these bodies is the main proposal of this work. These bodies had been mapped in order to characterize them properly in the regional stratigraphic context. The main outcrops were recognized in the Bola Hill and surroundings, where they are irregularly distributed, covering an area greater than 5 km². Dome and lava flow structures are present with the light gray andesite - phenoandesite rock. These outcrops can be correlated with the Pircas volcanic unit (Miocene, to the west, and could be further related to other porphyry bodies of different composition, situated both in Chita Creek and in Divisadero Hill. The extension of the area, lithological uniformity, the low alteration and a K/Ar radiometric age were considered, in order to propose these subvolcanic and volcanic bodies as a new lithostratigraphic unit, Upper Miocene in age, denominated "Cerro Bola Andesite".

  2. Comparison of Molecular Iodine Spectral Properties at 514.7 and 532 nm Wavelengths

    Directory of Open Access Journals (Sweden)

    Hrabina J.

    2014-08-01

    Full Text Available We present results of investigation and comparison of spectral properties of molecular iodine transitions in the spectral region of 514.7 nm that are suitable for laser frequency stabilization and metrology of length. Eight Doppler-broadened transitions that were not studied in detail before were investigated with the help of frequency doubled Yb-doped fiber laser, and three of the most promising lines were studied in detail with prospect of using them in frequency stabilization of new laser standards. The spectral properties of hyperfine components (linewidths, signal-to-noise ratio were compared with transitions that are well known and traditionally used for stabilization of frequency doubled Nd:YAG laser at the 532 nm region with the same molecular iodine absorption. The external frequency doubling arrangement with waveguide crystal and the Yb-doped fiber laser is also briefly described together with the observed effect of laser aging.

  3. 980-nm Q-switched photonic crystal fiber laser by MoS2 saturable absorber

    Science.gov (United States)

    Li, Pingxue; Liang, Boxing; Su, Meng; Zhang, Yuefei; Zhao, Yan; Zhang, Mengmeng; Ma, Chunmei; Su, Ning

    2016-05-01

    We demonstrate a 980-nm Q-switch Yb-doped photonic crystal fiber laser by a multilayer molybdenum sulfide polymer composite as the broadband saturable absorber which is prepared by the chemical vapor deposition method. We achieve passively Q-switching operations at 978 nm with the pulse width of 2.7 and 0.63 μs, corresponding to the repetition rate of 212 and 221 kHz, respectively. The maximum output power is 127 mW. It is the first time that MoS2 Q-switched Yb-doped photonic crystal fiber laser at 980 nm is demonstrated. The experimental results show that few-layer MoS2 is a promising broadband saturable absorber material.

  4. Effect of ytterbium inclusion in hafnium oxide on the structural and electrical properties of the high-k gate dielectric

    Institute of Scientific and Technical Information of China (English)

    陈帅; 刘正堂; 冯丽萍; 车兴森; 赵小如

    2014-01-01

    The undoped and Yb-doped HfO2 thin films were deposited on p-type single crystal Si(100) substrates using RF magnetron sputtering method. The structure and electrical properties were investigated as a function of doping concentrations. The results showed that the presence of Yb could stabilize HfO2 in cubic phase. The dielectric constant was enhanced after in-troducing Yb3+ ions into the HfO2 host. Compared with undoped HfO2 thin film, the Yb-doped HfO2 thin film exhibited a low leakage current. The silicate reaction between rare earth ions and SiO2 layers was used to eliminate interfacial silica and form a stable interface.

  5. Effect of Structural Stress on the Laser Quality of Highly Doped Yb:KY(WO4)2/KY(WO4)2 and Yb:KLu(WO4)2/KLu(WO4)2 Epitaxial Structures

    Energy Technology Data Exchange (ETDEWEB)

    Carvajal, J.; Raghothamachar, B; Silvestre, O; Chen, H; Pujol, M; Petrov, V; Dudley, M; Aguilo, M; Diaz, F

    2009-01-01

    In this communication we demonstrate how the difference in laser performance of two highly doped (20 at %) epitaxial layers of Yb-doped KY(WO4)2 (KYW) grown on a KYW substrate and Yb-doped KLu(WO4)2 (KLuW) grown on a KLuW substrate, respectively, is related to the presence of structural stress in the epilayers, investigated by synchrotron white beam X-ray topography. From the results obtained, it is clear that the samples that show a larger amount of structural stress, Yb:KYW/KYW epitaxies, lead to lower efficiency in laser operation, giving a direct correlation between the existence and magnitude of such structural stress and the loss in efficiency of laser performance in such epitaxial layers which, from a spectroscopical point of view, are otherwise equivalent.

  6. Generation of 14  W at 589  nm by frequency doubling of high-power CW linearly polarized Raman fiber laser radiation in MgO:sPPLT crystal.

    Science.gov (United States)

    Surin, A A; Borisenko, T E; Larin, S V

    2016-06-01

    We introduce an efficient, single-mode, linearly polarized continuous wave (CW) Raman fiber laser (RFL), operating at 1178 nm, with 65 W maximum output power and a narrow linewidth of 0.1 nm. Single-pass second-harmonic generation was demonstrated using a 20 mm long MgO-doped stoichiometric periodically polled lithium tantalate (MgO:sPPLT) crystal pumped by RFL radiation. Output power of 14 W at 589 nm with 22% conversion efficiency was achieved. The possibility of further power scaling is considered, as no crystal degradation was observed at these power levels. PMID:27244435

  7. 52 W kHz-linewidth low-noise linearly-polarized all-fiber single-frequency MOPA laser

    Science.gov (United States)

    Yang, Changsheng; Xu, Shanhui; Chen, Dan; Zhang, Yuanfei; Zhao, Qilai; Li, Can; Zhou, Kaijun; Feng, Zhouming; Gan, Jiulin; Yang, Zhongmin

    2016-05-01

    An all-fiber Yb-doped kHz-linewidth low-noise linearly polarized single-frequency master-oscillator power-amplifier (MOPA) laser with a stable CW output power of >52 W is demonstrated. By suppressing the intensity noise of the DBR phosphate fiber oscillator, the linewidth of MOPA laser is not noticeably broadened, and an ultra-narrow linewidth of 63 dB are achieved.

  8. BLUE COOPERATIVE UP-CONVERSION LUMINESCENCE OF Yb3+ IONS IN OXYFLUORIDE GLASS EXCITED BY 960 nm LASER

    Institute of Scientific and Technical Information of China (English)

    CHEN XIAO-BO; SONG ZENG-FU; N. SAWANOBORI

    2001-01-01

    Investigates the up-conversion luminescence of Yb-doped oxyfluoride glass excited by a 960nm-diode laser. A new up-conversion cooperative radiation luminescence is found, which is rather strong and positioned at 476.1 nm. It comes from the coupled states of two-Yb3+-ions cluster. It is significant because it is an effective and convenient method of producing blue light.

  9. Theoretical analysis of thermal effects in fiber laser from the moment when pump is turned on to steady-state

    Institute of Scientific and Technical Information of China (English)

    Zilun Chen; Jing Hou; Zongfu Jiang

    2007-01-01

    A theoretical analysis of the pump-induced temperature change and associated thermal phase shift occurring in a fiber laser is presented. The temperature rise and thermal phase shift from the moment when pump is turned on to steady-state in fiber lasers, such as Yb-doped fiber laser, are numerical calculated.With the same parameters, the numerical solution is in good agreement with the finite-element (ANSYS software) simulation.

  10. Millijoule pulse energy picosecond fiber chirped-pulse amplification system

    Institute of Scientific and Technical Information of China (English)

    Zhi Yang; Xiaohong Hu; Yishan Wang; Wei Zhang; Wei Zhao

    2011-01-01

    @@ The efficient generation of a 1.17-mJ laser pul8e with 360 ps duration using an ytterbium (Yb)-doped fiber amplifier chain seeded by a homemade mode-locked fiber laser is demonstrated experimentally.A specially designed figure-of-eight fiber laser acts as the seed source of a chirped-pulse amplification (CPA) system and generates mode-locked pulse8 with hundreds of picosecond widths.Two kinds of large-mode-area (LMA) double-clad Yb-doped fibers are employed to construct the pre-amplifier and main amplifier, All of the adopted instruments help avoid severe nonlinearity in fibers to raise sub-nanosecond pulse energy with acceptable signal-to-noise ratio (SNR).The output spectrum of this fiber-based CPA system shows that amplified spontaneous emission (ASE) is suppressed to better than 30 dB, and the onset of stimulated Raman scattering is excluded.%The efficient generation of a 1.17-mJ laser pulse with 360 ps duration using an ytterbium (Yb)-doped fiber amplifier chain seeded by a homemade mode-locked fiber laser is demonstrated experimentally. A specially designed figure-of-eight fiber laser acts as the seed source of a chirped-pulse amplification (CPA) system and generates mode-locked pulses with hundreds of picosecond widths. Two kinds of large-mode-area (LMA) double-clad Yb-doped fibers are employed to construct the pre-amplifier and main amplifier. All of the adopted instruments help avoid severe nonlinearity in fibers to raise sub-nanosecond pulse energy with acceptable signal-to-noise ratio (SNR). The output spectrum of this fiber-based CPA system shows that amplified spontaneous emission (ASE) is suppressed to better than 30 dB, and the onset of stimulated Raman scattering is excluded.

  11. Power-scalable internal frequency doubling scheme for continuous-wave fiber lasers

    OpenAIRE

    Cieslak, Rafal; Clarkson, W.Andrew

    2011-01-01

    We describe a simple power-scalable concept for efficient second harmonic generation in a cladding-pumped continuous-wave fiber laser. Our approach makes use of an internal resonant enhancement cavity to increase the intracavity power and second harmonic conversion efficiency without the need for active cavity length control and stabilization. This technique has been applied to a cladding-pumped Yb-doped fiber laser yielding 15 W of linearly-polarized continuous-wave green output (at 540 nm) ...

  12. Continuous-wave all-fiber MOPA with SBS phase conjugate mirror

    OpenAIRE

    Kovalev, V.I.; Harrison, R. G.; Sahu, J.K.; Nilsson, J.; Lebedev, P. N.

    2004-01-01

    A CW Nd:YAG master oscillator - fibre power amplifier (MOPFA) with fiber based SBS phase conjugate mirror is reported. A two-pass amplifier configuration is employed to compensate beam distortions in the multi-mode diode pumped Yb-doped fiber amplifier in conjunction with a fibre phase conjugator. The compensation of distortions is observed with ~30% of the total reflected power being of diffraction limited quality. Possibilities for improving the beam quality and power scaling in this system...

  13. Imaging of Bloch oscillations in erbium-doped curved waveguide arrays.

    Science.gov (United States)

    Chiodo, N; Della Valle, G; Osellame, R; Longhi, S; Cerullo, G; Ramponi, R; Laporta, P; Morgner, U

    2006-06-01

    We report a direct observation of Bloch-like dynamics of light in curved waveguide arrays manufactured in Er:Yb-doped phosphate glass by femtosecond laser writing. The green upconversion fluorescence emitted by excited erbium ions is exploited to image the flow of the guided pump light at approximately 980 nm along the array. Direct and clear evidence of periodic light breathing for single-waveguide excitation, closely related to Bloch oscillations, is reported.

  14. 7+1 to 1 pump/signal combiner for air-clad fiber with 15 m MFD PM single-mode signal feed-through

    DEFF Research Database (Denmark)

    Noordegraaf, Danny; Nielsen, Martin D.; Skovgaard, Peter M. W.;

    2010-01-01

    A 7+1 to 1 pump/signal combiner with single-mode (SM) polarization maintaining (PM) 15 µm mode-field-diameter (MFD) signal feed-through is demonstrated. The combiner is designed for pulse amplification in an active Yb-doped airclad fiber operated in backward pumped configuration. Signal coupling...... through the device is realized by a microstructured taper element allowing single-mode guidance and constant MFD at a taper ratio of 3.4....

  15. High-power continuous-wave frequency-doubling in KTiOAsO4.

    Science.gov (United States)

    Zeil, Peter; Zukauskas, Andrius; Tjörnhammar, Staffan; Canalias, Carlota; Pasiskevicius, Valdas; Laurell, Fredrik

    2013-12-16

    High-power continuous-wave generation at 533 nm is demonstrated in bulk periodically poled KTiOAsO(4) (KTA) by single-pass frequency doubling of a VBG-locked Yb-doped fiber laser. Absorption characteristic and second harmonic generation (SHG) performance of different KTA samples are studied and compared. The best performing sample catered for 25%-efficient SHG of 13.6 W green light with high spatial beam quality M(2) <1.2. PMID:24514622

  16. Erbium–ytterbium fibre laser emitting more than 13W of power in 1.55 m region

    Indian Academy of Sciences (India)

    Srikanth Gurram; Antony Kuruvilla; Rajpal Singh; Blacius Ekka; B N Upadhyay; K S Bindra; S M Oak

    2014-01-01

    We report the work on erbium:ytterbium-doped double clad fibre laser (EYDFL), that is pumped at 976 nm. The maximum output power generated is 13.6Win 1550 nm region with a slope efficiency of about 21%. To the best of our knowledge, this is the highest power reported from an EYDFL, that uses commercially available off-the-shelf large mode area Er:Yb-doped double-clad fibre.

  17. Tunable femtosecond Cherenkov fiber laser

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Svane, Ask Sebastian; Lægsgaard, Jesper;

    2014-01-01

    We demonstrate electrically-tunable femtosecond Cherenkov fiber laser output at the visible range. Using an all-fiber, self-starting femtosecond Yb-doped fiber laser as the pump source and nonlinear photonic crystal fiber link as the wave-conversion medium, ultrafast, milliwatt-level, tunable...... and spectral isolated Cherenkov radiation at visible wavelengths are reported. Such a femtosecond Cherenkov laser source is promising for practical biophotonics applications....

  18. Improved thermal stability and narrowed line width of photoluminescence from InGaN nanorod by ytterbium doping

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jingzhou; Wright, Jason; Kaya, S.; Jadwisienczak, W.M. [School of Electrical Engineering and Computer Science, Ohio University, Stocker Center, Athens OH 45701 (United States); Dasari, Kiran; Palai, Ratnakar [Department of Physics, University of Puerto Rico, San Juan, PR 00936 (United States); Cooper, Kevin; Thota, Venkata R.; Ingram, David C.; Stinaff, Eric A. [Department of Physics and Astronomy, Ohio University, Athens, OH 45701 (United States)

    2015-03-18

    Nanorod of in situ Yb-doped InGaN and undoped InGaN have been grown on (0001) sapphire substrates by plasma assisted molecular beam epitaxy (MBE). Selected regions on Yb-doped InGaN sample show single dominant near band edge emission (NBE) in green, yellow or orange color due to the variation of In content. Temperature dependent PL peak energy of InGaN nanorod shows the characteristic S -shaped behavior indicating the presents of strong exciton localization energy in undoped InGaN nanorod. The exciton localization energy reduced significantly after incorporating Yb into InGaN, giving rise to damping of the S-shape profile amplitude and narrowing of the PL line width from ∝20 meV to ∝12 meV at 11 K. It is proposed that the improved PL thermal stability and the PL line width in Yb-doped InGaN nanorod is affected by the Yb gettering effect. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Multi-kW cw fiber oscillator pumped by wavelength stabilized fiber coupled diode lasers

    Science.gov (United States)

    Becker, Frank; Neumann, Benjamin; Winkelmann, Lutz; Belke, Steffen; Ruppik, Stefan; Hefter, Ulrich; Köhler, Bernd; Wolf, Paul; Biesenbach, Jens

    2013-02-01

    High power Yb doped fiber laser sources are beside CO2- and disk lasers one of the working horses of industrial laser applications. Due to their inherently given robustness, scalability and high efficiency, fiber laser sources are best suited to fulfill the requirements of modern industrial laser applications in terms of power and beam quality. Pumping Yb doped single-mode fiber lasers at 976nm is very efficient. Thus, high power levels can be realized avoiding limiting nonlinear effects like SRS. However the absorption band of Yb doped glass around 976nm is very narrow. Therefore, one has to consider the wavelength shift of the diode lasers used for pumping. The output spectrum of passively cooled diode lasers is mainly defined by the applied current and by the heat sink temperature. Furthermore the overall emission line width of a high power pump source is dominated by the large number of needed diode laser emitters, each producing an individual spectrum. Even though it is possible to operate multi-kW cw single-mode fiber lasers with free running diode laser pumps, wavelength stabilizing techniques for diode lasers (e.g. volume holographic gratings, VHG) can be utilized in future fiber laser sources to increase the output power level while keeping the energy consumption constant. To clarify the benefits of wavelength stabilized diode lasers with integrated VHG for wavelength locking the performance of a dual side pumped fiber oscillator is discussed in this article. For comparison, different pumping configurations consisting of stabilized and free-running diode lasers are presented.

  20. Rare-earth-ion-doped ultra-narrow-linewidth lasers on a silicon chip and applications to intra-laser-cavity optical sensing

    Science.gov (United States)

    Bernhardi, E. H.; de Ridder, R. M.; Wörhoff, K.; Pollnau, M.

    2013-03-01

    We report on diode-pumped distributed-feedback (DFB) and distributed-Bragg-reflector (DBR) channel waveguide lasers in Er-doped and Yb-doped Al2O3 on standard thermally oxidized silicon substrates. Uniform surface-relief Bragg gratings were patterned by laser-interference lithography and etched into the SiO2 top cladding. The maximum grating reflectivity exceeded 99%. Monolithic DFB and DBR cavities with Q-factors of up to 1.35×106 were realized. The Erdoped DFB laser delivered 3 mW of output power with a slope efficiency of 41% versus absorbed pump power. Singlelongitudinal- mode operation at a wavelength of 1545.2 nm was achieved with an emission line width of 1.70 0.58 kHz, corresponding to a laser Q-factor of 1.14×1011. Yb-doped DFB and DBR lasers were demonstrated at wavelengths near 1020 nm with output powers of 55 mW and a slope efficiency of 67% versus launched pump power. An Yb-doped dualwavelength laser was achieved based on the optical resonances induced by two local phase shifts in the DFB structure. A stable microwave signal at ~15 GHz with a -3-dB width of 9 kHz and a long-term frequency stability of +/- 2.5 MHz was created via the heterodyne photo-detection of the two laser wavelengths. By measuring changes in the microwave beat signal as the intra-cavity evanescent laser field interacts with micro-particles on the waveguide surface, we achieved real-time detection and accurate size measurement of single micro-particles with diameters ranging between 1 μm and 20 μm, which represents the typical size of many fungal and bacterial pathogens. A limit of detection of ~500 nm was deduced.

  1. Reduction of Photoluminescence Quenching by Deuteration of Ytterbium-Doped Amorphous Carbon-Based Photonic Materials

    OpenAIRE

    Hui-Lin Hsu; Keith R. Leong; I-Ju Teng; Michael Halamicek; Jenh-Yih Juang; Sheng-Rui Jian; Li Qian; Nazir P. Kherani

    2014-01-01

    In situ Yb-doped amorphous carbon thin films were grown on Si substrates at low temperatures (<200 °C) by a simple one-step RF-PEMOCVD system as a potential photonic material for direct integration with Si CMOS back end-of-line processing. Room temperature photoluminescence around 1 µm was observed via direct incorporation of optically active Yb3+ ions from the selected Yb(fod)3 metal-organic compound. The partially fluorinated Yb(fod)3 compound assists the suppression of photoluminescence...

  2. Raman-scattering-assistant broadband noise-like pulse generation in all-normal-dispersion fiber lasers.

    Science.gov (United States)

    Li, Daojing; Shen, Deyuan; Li, Lei; Chen, Hao; Tang, Dingyuan; Zhao, Luming

    2015-10-01

    We report on the observation of both stable dissipative solitons and noise-like pulses with the presence of strong Raman scattering in a relatively short all-normal-dispersion Yb-doped fiber laser. We show that Raman scattering can be filtered out by intracavity filter. Furthermore, by appropriate intracavity polarization control, the Raman effect can be utilized to generate broadband noise-like pulses (NLPs) with bandwidth up to 61.4 nm. To the best of our knowledge, this is the broadest NLP achieved in all-normal-dispersion fiber lasers. PMID:26480103

  3. All-fiber, narrow linewidth and linearly polarized fiber laser in a single-mode-multimode-single-mode cavity.

    Science.gov (United States)

    Jiang, Man; Xu, Haiyang; Zhou, Pu; Zhao, Guomin; Gu, Xijia

    2016-08-01

    We report the design of an all-fiber, linearly polarized Yb-doped fiber laser at 1064 nm with a narrow linewidth and high output power required by the master oscillator of the amplifier for high-power spectral beam combining. The laser has achieved linearly polarized output with a polarization extinction ratio of 23 dB, a narrow linewidth of ≤52  pm, and an output power of 32.7 W. Such performance was obtained by the cavity design that incorporated a wavelength-shifted PM fiber Bragg grating pair and single-mode-multimode-single-mode structure. PMID:27505397

  4. Superconducting Dy1-x(Gd,Yb)xBa2Cu3O7-δ thin films made by Chemical Solution Deposition

    DEFF Research Database (Denmark)

    Opata, Yuri Aparecido; Wulff, Anders Christian; Hansen, Jørn Otto Bindslev;

    2016-01-01

    that doping with Yb significantly increased the self-field Jc value from 3.8 MA/cm2 to 6.0 MA/cm2 for the pureand 10 % Yb doped sample, respectively. In contrast, samples doped with Gd were characterized by the lowest self-field Jc values. Investigation of pinning force mechanisms revealed that the samples......-lattice constants were observed to decrease for all samples doped with Gd or Yb. Measurements of the onset critical transition temperature (Tonsetc ) were found to decrease with increasing Yb content, while only minor changes were observed for samples with Gd. Critical current density (Jc) analysis demonstrated...

  5. Enhanced 1.0 μm emission and simultaneously suppressed upconversion emission in Yb:PbF2 laser crystal codoped with NaF

    Science.gov (United States)

    Zhang, P. X.; Yin, J. G.; Hang, Y.; Yin, J. P.

    2013-04-01

    Na-codoped and only Yb-doped Yb:PbF2 crystals were successfully grown using the vertical Bridgman method. The influence of the ions codoped with Na+ on the distribution coefficients has been studied. Enhanced ˜1.0 μm emission and simultaneously suppressed upconversion emission was observed for Yb:PbF2 crystals codoped with 2 mol% NaF. A time-resolved spectroscopy study showed that the ions codoped with Na+ lengthen the fluorescence lifetime by 6%. Absorption spectra were also studied and showed that the ions codoped with Na+ can effectively suppress the formation of Yb2+ ions.

  6. LLE Review 119 (April-June 2009)

    Energy Technology Data Exchange (ETDEWEB)

    Edgell, D.H., editor

    2009-10-22

    This issue has the following articles: (1) Shock-Ignition Experiments on OMEGA at NIF-Relevant Intensities; (2) Laser-Driven Magnetic-Flux Compression in High-Energy-Density Plasmas; (3) Lorentz Mapping of Magnetic Fields in Hot, Dense Plasmas; (4) Characterization and Optimization of Yb-Doped Photonic-Crystal Fiber Rod Amplifiers Using Spatially Resolved Spectral Interferometry; (5) Optical Differentiation and Multimillijoule {approx}150-ps Pulse Generation in a Regenerative Amplifier with a Temperature-Tuned Intracavity Volume Bragg Grating; (6) Slow Crack Growth During Radiatiave Cooling of LHG8 and BK7 Plates; and (7) Finite Element Simulation of Metal-Semiconductor-Metal Photoconductor.

  7. Electro-optical Bunch Length Monitor for FLUTE: Layout and Simulations

    OpenAIRE

    Borysenko, A.; Hertle, E.; Schuh, M.; Schwarz, M.; Wesolowski, P.; Steffen, Bernd; Hiller, N.; Judin, V.; Kehrer, B.; Marsching, S.; Müller, A. -S.; Nasse, M. J.; Rossmanith, R.; Ruprecht, R.

    2014-01-01

    A new compact linear accelerator FLUTE is currently under construction at Karlsruhe Institute of Technology (KIT) in collaboration with DESY and PSI. It aims at obtaining femtosecond electron bunches (~1fs - 300 fs) with a wide charge range (1 pC - 3 nC) and requires a precise bunch length diagnostic system. Here we present the layout of a bunch length monitor based on the electro-optic technique of spectral decoding using an Yb-doped fiber laser system (central wavelength 1030 nm) and a GaP ...

  8. Fiber-comb-stabilized light source at 556 nm for magneto-optical trapping of ytterbium

    OpenAIRE

    Yasuda, Masami; Kohno, Takuya; Inaba, Hajime; Nakajima, Yoshiaki; Hosaka, Kazumoto; Onae, Atsushi; Hong, Feng-Lei

    2010-01-01

    A frequency-stabilized light source emitting at 556 nm is realized by frequency-doubling a 1112-nm laser, which is phase-locked to a fiber-based optical frequency comb. The 1112-nm laser is either an ytterbium (Yb)-doped distributed feedback fiber laser or a master-slave laser system that uses an external cavity diode laser as a master laser. We have achieved the continuous frequency stabilization of the light source over a five-day period. With the light source, we have completed the second-...

  9. All-fiber femtosecond Cherenkov radiation source.

    Science.gov (United States)

    Liu, Xiaomin; Lægsgaard, Jesper; Møller, Uffe; Tu, Haohua; Boppart, Stephen A; Turchinovich, Dmitry

    2012-07-01

    An all-fiber femtosecond source of spectrally isolated Cherenkov radiation is reported, to the best of our knowledge, for the first time. Using a monolithic, self-starting femtosecond Yb-doped fiber laser as the pump source and the combination of photonic crystal fibers as the wave-conversion medium, we demonstrate milliwatt-level, stable, and tunable Cherenkov radiation at visible wavelengths 580-630 nm, with pulse duration of sub-160-fs, and the 3 dB spectral bandwidth not exceeding 36 nm. Such an all-fiber Cherenkov radiation source is promising for practical applications in biophotonics such as bioimaging and microscopy. PMID:22743523

  10. All-fiber femtosecond Cherenkov radiation source

    OpenAIRE

    Liu, Xiaomin; Lægsgaard, Jesper; Møller, Uffe; Tu, Haohua; Boppart, Stephen A.; Turchinovich, Dmitry

    2012-01-01

    An all-fiber femtosecond source of spectrally isolated Cherenkov radiation is reported, to the best of our knowledge, for the first time. Using a monolithic, self-starting femtosecond Yb-doped fiber laser as the pump source and the combination of photonic crystal fibers as the wave-conversion medium, we demonstrate milliwatt-level, stable, and tunable Cherenkov radiation at visible wavelengths 580–630 nm, with pulse duration of sub-160-fs, and the 3 dB spectral bandwidth not exceeding 36 nm. ...

  11. Enhanced Visible Light Generation from 1 μm Femtosecond Pulses within High-Δ Photonic Crystal Fibers

    International Nuclear Information System (INIS)

    We demonstrate the blue light generated in high-Δ photonic crystal fibers (PCFs). A femtosecond Yb-doped fiber laser, operating at 1039nm, is used to pump a GeO2-doped PCF in the largely anomalous group velocity dispersion (GVD) region. The emitted radiation covers 418.6–544.6nm with 5dB flatness. The calculated result indicates that the cross phase module (XPM) effect induced by higher-mode soliton makes a contribution to the blue component generation. (fundamental areas of phenomenology(including applications))

  12. Raman-scattering-assistant broadband noise-like pulse generation in all-normal-dispersion fiber lasers

    CERN Document Server

    Li, Daojing; Li, Lei; Chen, Hao; Tang, Dingyuan; Zhao, Luming

    2015-01-01

    We report on the observation of both stable dissipative solitons and noise-like pulses with the presence of strong Raman scattering in a relatively short all-normal-dispersion Yb-doped fiber laser. We show that Raman scattering can be filtered out by intracavity filter. Furthermore, by appropriate intracavity polarization control, the Raman effect can be utilized to generate broadband noise-like pulses (NLPs) with bandwidth up to 61.4 nm. To the best of our knowledge, this is the broadest NLP achieved in all-normal-dispersion fiber lasers

  13. Biological oxygen sensing via two-photon absorption by an Ir(III) complex using a femtosecond fiber laser

    Science.gov (United States)

    Moritomo, Hiroki; Fujii, Akinari; Suzuki, Yasutaka; Yoshihara, Toshitada; Tobita, Seiji; Kawamata, Jun

    2016-09-01

    Near-infrared two-photon absorption of the phosphorescent Ir(III) complex (2,4-pentanedionato-κO 2,κO 4)bis[2-(6-phenanthridinyl-κN)benzo[b]thien-3-yl-κC]iridium (BTPHSA) was characterized. It exhibited a 800-1200 nm two-photon absorption band, and thus could be electronically excited by 1030-nm femtosecond Ti:sapphire and Yb-doped fiber lasers. By using BTPHSA, oxygen concentrations in human embryonic kidney 293 (HEK293) cells were imaged. These results demonstrate two-photon oxygen sensing of live tissues via easily operable excitation sources.

  14. LD-pumped solid-state lasers with improved frequency, spatial, and polarization characteristics for precise spectroscopic applications

    Science.gov (United States)

    Drakov, A. S.; Kostik, O. E.; Mashko, V. V.; Teplyashin, L. L.; Bogdanovich, M. V.; Enzhyieuski, A. I.; Pozhidaev, A. V.; Ryabtsev, A. G.; Ryabtsev, G. I.; Shchemelev, M. A.

    2007-06-01

    New methods for precise control of main parameters of LD-pumped solid-state lasers assigned for spectroscopic applications have been developed. Tunable lasing in wide range has been achieved. Active elements on the base of crystals (Nd 3+:YAG, Nd 3+:YVO 4) and glasses (Er,Yb doped boro-silico-phosphate glass) were used. The active crystals with uniform and non-uniform distribution of the activator ions were studied. Output beams with high quality and polarization degree have been realized.

  15. Highly Efficient Self-Starting Femtosecond Cr:Forsterite Laser

    Institute of Scientific and Technical Information of China (English)

    ZHOU Bin-Sin; ZHANG Yong-Dong; ZHONG Xin; WEI Zhi-Yi

    2008-01-01

    We report a highly efficient and high power self-starting femtosecond Cr:forsterite laser pumped by a 1064-nm Yb doped fibre laser. Five chirped mirrors are used to compensate for the intra-cavity group-delay dispersion,and the mode-locking is initiated by a semiconductor saturable absorber mirror (SESAM). Under pump power of 7.9 W, stable femtosecond laser pulses with average power of 760mW are obtained, yielding a pump power slope efficiency of 12.3%. The measured pulse duration and spectral bandwidth (FWHM) are 46 fs and 45 nm;the repetition rate is 82 MHz.

  16. Metastable Magnesium fluorescence spectroscopy using a frequency-stabilized 517 nm laser

    DEFF Research Database (Denmark)

    He, Ming; Jensen, Brian B; Therkildsen, Kasper T;

    2009-01-01

    We present a laser operating at 517 nm for our Magnesium laser-cooling and atomic clock project. A two-stage Yb-doped fiber amplifier (YDFA) system generates more than 1.5 W of 1034 nm light when seeded with a 15 mW diode laser. Using a periodically poled lithium niobate (PPLN) waveguide, we...... obtained more than 40 mW of 517 nm output power by single pass frequency doubling. In addition, fluorescence spectroscopy of metastable magnesium atoms could be used to stabilize the 517 nm laser to an absolute frequency within 1 MHz....

  17. Self-similar propagation and amplification of parabolic pulses in optical fibers.

    Science.gov (United States)

    Fermann, M E; Kruglov, V I; Thomsen, B C; Dudley, J M; Harvey, J D

    2000-06-26

    Ultrashort pulse propagation in high gain optical fiber amplifiers with normal dispersion is studied by self-similarity analysis of the nonlinear Schrödinger equation with gain. An exact asymptotic solution is found, corresponding to a linearly chirped parabolic pulse which propagates self-similarly subject to simple scaling rules. The solution has been confirmed by numerical simulations and experiments studying propagation in a Yb-doped fiber amplifier. Additional experiments show that the pulses remain parabolic after propagation through standard single mode fiber with normal dispersion.

  18. Ultrahigh-resolution optical coherence tomography at 1.3 μm central wavelength by using a supercontinuum source pumped by noise-like pulses

    Science.gov (United States)

    You, Yi-Jing; Wang, Chengming; Lin, Yi-Lun; Zaytsev, Alexey; Xue, Ping; Pan, Ci-Ling

    2016-02-01

    We report on the ultrahigh-resolution optical coherence tomography (OCT) with a novel high-power supercontinuum (SC) light source generated by noise-like pulses from an Yb-doped fiber laser. The SC spectrum is flat with a bandwidth of 420 nm centered around ~1.3 μm. The light source is successfully employed in a time-domain OCT (TD-OCT), achieving an axial resolution of 2.3 μm. High resolution fiber-based spectral-domain OCT (SD-OCT) imaging of bio-tissue was also demonstrated.

  19. Raman-scattering-assistant broadband noise-like pulse generation in all-normal-dispersion fiber lasers

    Science.gov (United States)

    Li, Daojing; Shen, Deyuan; Li, Lei; Chen, Hao; Tang, Dingyuan; Zhao, Luming

    2015-10-01

    We report on the observation of both stable dissipative solitons and noise-like pulses with the presence of strong Raman scattering in a relatively short all-normal-dispersion Yb-doped fiber laser. We show that Raman scattering can be filtered out by intracavity filter. Furthermore, by appropriate intracavity polarization control, the Raman effect can be utilized to generate broadband noise-like pulses (NLPs) with bandwidth up to 61.4 nm. To the best of our knowledge, this is the broadest NLP achieved in all-normal-dispersion fiber lasers

  20. Generation of double-scale femto/pico-second optical lumps in mode-locked fiber lasers.

    Science.gov (United States)

    Kobtsev, Sergey; Kukarin, Sergey; Smirnov, Sergey; Turitsyn, Sergey; Latkin, Anton

    2009-11-01

    We observed generation of stable picoseconds pulse train and double-scale optical lumps with picosecond envelope and femtosecond noise-like oscillations in the same Yb-doped fiber laser with all-positive-dispersion cavity mode-locked due to the effect of non-linear polarization evolution. In the noise-like pulse generation regime the auto-correlation function has a non-usual double (femto- and picosecond) scale shape. We discuss mechanisms of laser switching between two operation regimes and demonstrate a good qualitative agreement between experimental results and numerical modeling based on modified nonlinear Schrödinger equations. PMID:19997301

  1. Raman-scattering-assistant broadband noise-like pulse generation in all-normal-dispersion fiber lasers

    OpenAIRE

    Li, Daojing; Shen, Deyuan; Li, Lei; Chen, Hao; Tang, Dingyuan; Zhao, Luming

    2015-01-01

    We report on the observation of both stable dissipative solitons and noise-like pulses with the presence of strong Raman scattering in a relatively short all-normal-dispersion Yb-doped fiber laser. We show that Raman scattering can be filtered out by intracavity filter. Furthermore, by appropriate intracavity polarization control, the Raman effect can be utilized to generate broadband noise-like pulses (NLPs) with bandwidth up to 61.4 nm. To the best of our knowledge, this is the broadest NLP...

  2. Multi-pulse operation of a dissipative soliton fibre laser based on nonlinear polarisation rotation

    Science.gov (United States)

    Yu, H. L.; Wang, X. L.; Zhou, P.; Chen, J. B.

    2016-03-01

    We report an experimental observation of multiple dissipative soliton (DS) operation states in an all-normal-dispersion passively mode-locked Yb-doped fibre laser, including DS bound and oscillating states. In the bound state, multiple DSs up to 11 can coexist in the cavity. In the oscillating state, the DSs' movements are not purely random and three typical states are generalised and illustrated. A single-pulse mode-locked state is established at a high pump power by carefully adjusting the polarisation controllers. The broad spectrum indicates that it may be noise-like pulses, which can serve as a pump to generate a supercontinuum.

  3. Optimized all-fiber supercontinuum source at 1.3 μm generated in a stepwise dispersion-decreasing-fiber arrangement

    OpenAIRE

    Abrardi, Laura; Martín López, Sonia; Carrasco-Sanz, Ana; Corredera, Pedro; Hernanz, María Luisa; González Herráez, Miguel

    2007-01-01

    In this paper, the generation of a continuous-wave (CW)-pumped supercontinuum (SC) source at 1.3 μm is described. The device makes use of a tunable Yb-doped fiber laser, a cascade of Fiber Bragg Grating mirrors, and a concatenation of standard silica fibers with stepwise decreasing dispersion. It is shown that the dispersion-decreasing-fiber set enhances the width of the generated SC, since it favors the fission of the CW input into high-order solitons. The generated SC spans from 1280 to 151...

  4. RGB generation by four-wave mixing in small-core holey fibers

    OpenAIRE

    Horak, P.; Dupriez, P.; Poletti, F.; Petrovich, M.N.; Jeong, Y.; Nilsson, J.; Richardson, D J; Payne, D. N.

    2007-01-01

    We report the generation of white light comprising red, green, and blue spectral bands from a frequency-doubled fiber laser by an efficient four-wave mixing process in submicron-sized cores of microstructured holey fibers. A master-oscillator power amplifier (MOPA) source based on Yb-doped fiber is employed to generate 80 ps pulses at 1060 nm wavelength with 32 MHz repetition rate, which are then frequency-doubled in an LBO crystal to generate up to 2 W average power of green light. The green...

  5. Internally-frequency-doubled Yb fiber laser with 15 W CW green output

    OpenAIRE

    Cieslak, Rafal; Clarkson, William Andrew

    2011-01-01

    In this paper we present a high power continuous-wave (CW) green source using a novel approach for frequency doubling of high power CW fiber lasers based on an internal resonant enhancement cavity integrated within the fiber laser resonator. The experimental configuration (shown in Fig. 1) comprised a double-clad fiber with an Yb-doped core in a simple standing-wave resonator. Feedback for lasing was provided by a diffraction grating at one end of the fiber, and by an external cavity containi...

  6. Multi-mJ bursts of green light obtained by frequency doubling the output of a fiber based MOPA

    Science.gov (United States)

    Rowen, Eitan E.; Shalev, Nir; Tal, Eran; Lasri, Kobi; Inbar, Eran

    2016-03-01

    We demonstrate a fiber laser that generates bursts of 70-300 pulses at a frequency of 2-8 MHz with over 4 mJ of energy per burst at a wavelength of 532 nm. The output of an Yb-doped fiber amplifier chain is doubled in a single pass through an LBO crystal with efficiency of above 65%. A seed-diode generates the pulse train, which is amplified to a peak power that allows efficient SHG. Such a solution may have many industrial and other applications, where fiber-based solutions have many advantages, but suffer a disadvantage of relatively low pulse energy.

  7. SBS-managed high-peak-power nanosecond-pulse fiber-based master oscillator power amplifier.

    Science.gov (United States)

    Di Teodoro, F; Morais, J; McComb, T S; Hemmat, M K; Cheung, E C; Weber, M; Moyer, R

    2013-07-01

    We report on a compactly packaged Yb-doped fiber-based laser architecture featuring an actively pulse controlled, single-longitudinal-mode seeder and multistage amplifier chain terminated by a "folded" rod-type photonic crystal fiber. In this laser source, stimulated Brillouin scattering (SBS) is the power-limiting factor, but is managed by phase modulating the seeder with a pseudo-random noise signal. Pulse energy/peak power of ~2 mJ/1.5 MW at 10 kHz repetition rate are thus obtained within ~1.55 ns pulses of peak spectral brightness >20 kW cm(-2) sr(-1) Hz(-1). PMID:23811864

  8. Tandem-pumped 1120-nm actively Q-switched fiber laser

    Institute of Scientific and Technical Information of China (English)

    王建华; 胡金萌; 张世强; 陈露璐; 房勇; 冯衍

    2015-01-01

    We report on a tandem-pumped actively Q-switched fiber laser system emitting at 1120 nm. Parasitic oscillation is challenging in Yb-doped Q-switched 1120-nm fiber laser, which is suppressed by pumping with a fiber laser at 1018 nm. At least 4 times improvement in output peak power is demonstrated in a single laser setup with 1018-nm fiber laser pumping instead of 976-nm laser diode pumping. This is, to the best of our knowledge, the first demonstration of a tandem-pumped Q-switched fiber laser.

  9. Observation of soliton explosions in a passively mode-locked fiber laser

    OpenAIRE

    Runge, Antoine F. J.; Broderick, Neil G.R.; Erkintalo, Miro

    2014-01-01

    Soliton explosions are among the most exotic dissipative phenomena studied in mode-locked lasers. In this regime, a dissipative soliton circulating in the laser cavity experiences an abrupt structural collapse, but within a few roundtrips returns to its original quasi-stable state. In this work we report on the first observation of such events in a fiber laser. Specifically, we identify clear explosion signatures in measurements of shot-to-shot spectra of an Yb-doped mode-locked fiber laser t...

  10. LLE Review 119 (April-June 2009)

    International Nuclear Information System (INIS)

    This issue has the following articles: (1) Shock-Ignition Experiments on OMEGA at NIF-Relevant Intensities; (2) Laser-Driven Magnetic-Flux Compression in High-Energy-Density Plasmas; (3) Lorentz Mapping of Magnetic Fields in Hot, Dense Plasmas; (4) Characterization and Optimization of Yb-Doped Photonic-Crystal Fiber Rod Amplifiers Using Spatially Resolved Spectral Interferometry; (5) Optical Differentiation and Multimillijoule ∼150-ps Pulse Generation in a Regenerative Amplifier with a Temperature-Tuned Intracavity Volume Bragg Grating; (6) Slow Crack Growth During Radiatiave Cooling of LHG8 and BK7 Plates; and (7) Finite Element Simulation of Metal-Semiconductor-Metal Photoconductor.

  11. The spectroscopic properties of Yb3+ doped α-BBO crystal

    Science.gov (United States)

    Yu, Pingsheng; Su, Liangbi; Wu, Feng; Xu, Jun

    2012-05-01

    2.0 mol% (relative to Ba2+) Yb3+ doped α-BaB2O4 (α-BBO) crystal was obtained by the Czochralski method. The doped crystal structure was determined by means of an X-ray diffraction analysis. The absorption, near-infrared (NIR) luminescence spectra and fluorescence decay curve of Yb3+ doped α-BBO crystal were investigated. NIR emission under 940 nm and 980 nm LDs (laser diodes) excitation was observed in the Yb doped α-BBO crystal.

  12. Monolithic Yb-fiber femtosecond laser with intracavity all-solid PBG fiber and ex-cavity HC-PCF

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Liu, Xiaomin; Lægsgaard, Jesper

    2010-01-01

    (PM) photonic bandgap fiber (PBG) is used in the cavity of the master oscillator for dispersion compensation and stabilization of modelocking. The final compression of an chirped-pulse-amplified laser signal is performed in a hollow PM PCF, yielding final fiber-delivered pulse energy of around 7 n......We demonstrate an all-fiber femtosecond master oscillator / power amplifier operating at the central wavelength of 1033 nm, based on Yb-doped fiber as gain medium, and two different kinds of photonic crystal fibers for dispersion control and stabilization. An all-solid (AS) polarization maintaining...

  13. Influence of mode competition on beam quality of fiber amplifier

    International Nuclear Information System (INIS)

    Theoretical and experimental studies of the influence of the mode competition on the output beam quality of fiber amplifiers are presented. Rate equations and modal decomposition method are used in the theoretical model. In the experiment, the output beam-quality factor of a fiber amplifier, which is based on a Yb-doped double-clad large mode area fiber as a function of the seed beam quality and the pump power of the amplifier, is measured. The experimental results are consistent with the theoretical analysis. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  14. Synthesis–property relationship in thermoelectric Sr 1− x Yb x TiO 3− δ ceramics

    KAUST Repository

    Bhattacharya, S

    2014-08-22

    The electronic transport properties of a series of Sr1-xYbxTiO3-delta (x = 0.05, 0.1) ceramics are investigated as a function of solid-state reaction (SSR) parameters, specifically calcination steps. It was found that the electrical conductivity (sigma) increases almost by a factor of 6, through the optimization of SSR parameters. The enhancement in the electrical conductivity leads to an enhancement in the thermoelectric power factor by a factor of 3. In addition, the lattice thermal conductivity (k(L)) of the Sr1-xYbxTiO3-delta ceramics is suppressed with increasing Yb-doping, supposedly due to heavier atomic mass of Yb substituted at the Sr site and a smaller ionic radii of Yb+3 with respect to Sr+2 ions. However, our model calculations indicate that strain-field effect, which occurs due to the difference in ionic radii, is the more prominent phonon scattering mechanism in the Yb-doped SrTiO3. This work is an extension of our previous study on the underlying phonon scattering mechanisms in the Y-doped SrTiO3, which would provide new insight into thermal transport in doped SrTiO3 and could be used as a guideline for more effective material synthesis.

  15. Visible photoluminescence and room temperature ferromagnetism in high In-content InGaN:Yb nanorods grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Dasari, K.; Palai, R., E-mail: r.palai@upr.edu [Department of Physics, University of Puerto Rico, San Juan, Puerto Rico 00936 (United States); Wang, J.; Jadwisienczak, W. M. [School of Electrical Engineering and Computer Science, Ohio University, Athens, Ohio 45701-2979 (United States); Guinel, M. J.-F. [Department of Physics, University of Puerto Rico, San Juan, Puerto Rico 00936 (United States); Department of Chemistry, University of Puerto Rico, San Juan, Puerto Rico 00936 (United States); Huhtinen, H. [Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, Turku FI-20014 (Finland); Mundle, R.; Pradhan, A. K. [Department of Engineering, Norfolk State University, 700 Park Avenue, Norfolk, Virginia 23504 (United States)

    2015-09-28

    We report the growth of high indium content InGaN:Yb nanorods grown on c-plane sapphire (0001) substrates using plasma assisted molecular beam epitaxy. The in situ reflection high energy electron diffraction patterns recorded during and after the growth revealed crystalline nature of the nanorods. The nanorods were examined using electron microscopy and atomic force microscopy. The photoluminescence studies of the nanorods showed the visible emissions. The In composition was calculated from x-ray diffraction, x-ray photoelectron spectroscopy, and the photoluminescence spectroscopy. The In-concentration was obtained from photoluminescence using modified Vegard's law and found to be around 37% for InGaN and 38% for Yb (5 ± 1%)-doped InGaN with a bowing parameter b = 1.01 eV. The Yb-doped InGaN showed significant enhancement in photoluminescence properties compared to the undoped InGaN. The Yb-doped InGaN nanorods demonstrated the shifting of the photoluminescence band at room temperature, reducing luminescence amplitude temperature dependent fluctuation, and significant narrowing of excitonic emission band as compared to the undoped InGaN. The magnetic properties measured by superconducting quantum interference devices reveals room temperature ferromagnetism, which can be explained by the double exchange mechanism and magnetostriction.

  16. Flow sensor using a hollow whispering gallery mode microlaser

    Science.gov (United States)

    Ward, Jonathan M.; Yang, Yong; Chormaic, Síle N.

    2016-03-01

    Flow sensing using the concept of a hot whispering gallery microlaser is presented. Silica microcapillaries or microbubbles, coated with a layer of erbium:ytterbium (Er:Yb) doped phosphate laser glass, result in a hollow, microbottle-shaped laser geometry. The Er:Yb doped glass outer layer is pumped at 980 nm via a tapered optical fiber and whispering gallery mode (WGM) lasing is recorded at 1535 nm. When gas passes through the capillary, the WGMs shift toward shorter wavelengths due to the cooling effect of the fluid flow. In this way, thermal tuning of the lasing modes over 70 GHz can be achieved. The output end of the capillary is connected to a mass flow sensor and the WGM shift rate as a function of flow rate and pump laser power is measured, with the results fitted using hot wire anemometry theory. Flow sensing can also be realized when the cavity is passively probed at 780 nm, with the estimated Q-factor of the WGMs being in excess of 105.

  17. High power linearly polarized Raman fiber laser at 1120 nm

    Institute of Scientific and Technical Information of China (English)

    Jianhua Wang; Lei Zhang; Jun Zhou; Lei Si; Jinbao Chen; Yan Feng

    2012-01-01

    An all-fiber linearly polarized Raman fiber laser at 1 120 nm is demonstrated.With a 1 070-nm linearly polarized Yb-doped fiber laser as pump source,an output of up to 7.7 W at 1 120 nm is obtained with an optical efficiency of 55%.The polarization extinction ratio of the linearly polarized Raman fiber is higher than 18 dB.A numerical simulation model is developed to determine the Raman coefficient of the gain fiber and to evaluate the laser performance.The spectral isolation between the Raman fiber laser and the pump fiber laser is determined to be necessary for further improvements of performance.%An all-fiber linearly polarized Raman fiber laser at 1120 nm is demonstrated. With a 1070-nm linearly polarized Yb-doped fiber laser as pump source, an output of up to 7.7 W at 1120 nm is obtained with an optical efficiency of 55%. The polarization extinction ratio of the linearly polarized Raman fiber is higher than 18 dB. A numerical simulation model is developed to determine the Raman coefficient of the gain fiber and to evaluate the laser performance. The spectral isolation between the Raman fiber laser and the pump fiber laser is determined to be necessary for further improvements of performance.

  18. Components for monolithic fiber chirped pulse amplification laser systems

    Science.gov (United States)

    Swan, Michael Craig

    The first portion of this work develops techniques for generating femtosecond-pulses from conventional fabry-perot laser diodes using nonlinear-spectral-broadening techniques in Yb-doped positive dispersion fiber ampliers. The approach employed an injection-locked fabry-perot laser diode followed by two stages of nonlinear-spectral-broadening to generate sub-200fs pulses. This thesis demonstrated that a 60ps gain-switched fabry-perot laser-diode can be injection-locked to generate a single-longitudinal-mode pulse and compressed by nonlinear spectral broadening to 4ps. Two problems have been identified that must be resolved before moving forward with this approach. First, gain-switched pulses from a standard diode-laser have a number of characteristics not well suited for producing clean self-phase-modulation-broadened pulses, such as an asymmetric temporal shape, which has a long pulse tail. Second, though parabolic pulse formation occurs for any arbitrary temporal input pulse profile, deviation from the optimum parabolic input results in extensively spectrally modulated self-phase-modulation-broadened pulses. In conclusion, the approach of generating self-phase-modulation-broadened pulses from pulsed laser diodes has to be modified from the initial approach explored in this thesis. The first Yb-doped chirally-coupled-core ber based systems are demonstrated and characterized in the second portion of this work. Robust single-mode performance independent of excitation or any other external mode management techniques have been demonstrated in Yb-doped chirally-coupled-core fibers. Gain and power efficiency characteristics are not compromised in any way in this novel fiber structure up to the 87W maximum power achieved. Both the small signal gain at 1064nm of 30.3dB, and the wavelength dependence of the small signal gain were comparable to currently deployed large-mode-area-fiber technology. The efficiencies of the laser and amplifier were measured to be 75% and 54

  19. Influence of Zn Ions Codoping on Luminescence Properties of PbWO4:RE (RE=La, Yb, Y)

    Institute of Scientific and Technical Information of China (English)

    XU Yan-Ling; WANG Rui; WANG Bin-Ju; LIU Wei-Hai; WANG Jia; WANG Miao; YANG Tong-Yong

    2008-01-01

    Zn and RE (RE=La, Yb, Y) ions co-doped PbWO4 (PWO) single crystal grown by the Czochralski technique are characterized by x-ray diffraction (XRD), optical transmission spectra, and photoluminescence (PL). The doping of Zn ions shows distinct effects on the properties of PWO:RE crystals. At low concentration of Zn ions (200ppm), the luminescence intensity is quite weak for (Zn,La)-doped PWO, but is substantially strong for (Zn, Yb)-doped PWO. The blue luminescence intensity is significantly enhanced with the increasing Zn ions doping for PWO:Y. The trivalent ions codoping can increase the ratio of the blue luminescence contributing to the fast components of light yield. Yb ions can enhance efficiency of luminescence in PWO:Yb:Zn because they may act as a luminous sensitization agent which can be involved in the efficient energy transfer and storage of the radiative process.

  20. 110  W all-fiber picosecond master oscillator power amplifier based on large-core-diameter ytterbium-doped fiber.

    Science.gov (United States)

    Yu, Zhenhua; Shi, Wei; Dong, Xinzheng; Li, Jinhui; Zhao, Yizhu; Liu, Huixian

    2016-05-20

    We demonstrate an all-fiber picosecond fiber laser in a master oscillator power amplifier configuration. The seed source is a soliton-type passively mode-locked Yb-doped fiber laser by a semiconductor saturable absorber mirror and chirped fiber Bragg grating. The pulse width of the seed laser is 4.5 ps with a repetition rate of 15 MHz. A highly doped active fiber with a large core diameter (50 μm) is employed to boost the average power of the seed pulses to 117 W with 11 ps pulse width and 709 kW peak power. The corresponding output beam quality factor at maximum output power is 3.7. The all-fiber construction of the whole laser system enables compact size and robust operation. PMID:27411140

  1. Yb hybrid laser system of DAW RF gun for SuperKEKB

    International Nuclear Information System (INIS)

    SuperKEKB is a planned upgrade to the KEKB accelerator with higher luminosity. Corresponding to the reduction of dynamic aperture and beam life, the photocathode DAW-type RF gun for high-current, low-emittance beams will be employed in the injector linac. The electron beams with a charge of 5 nC and a normalized emittance of 10 μm are expected to be generated in the RF gun by using the laser source at A-1 unit. Introducing the Ytterbium (Yb) hybrid laser system that includes Yb-doped fiber and Yb:YAG solid system, generates mJ pulses with a center wavelength of 258 nm and a pulse width of 30 ps. 1.0 nC beam generation from the RF gun was achieved. (author)

  2. Spectrally tailored supercontinuum generation from single-mode-fiber amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Qiang; Guo, Zhengru; Zhang, Qingshan [Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System (Ministry of Education), School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093 (China); Liu, Yang; Li, Wenxue [State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 Zhongshan North Road, Shanghai 200062 (China); Zeng, Heping, E-mail: hpzeng@phy.ecnu.edu.cn [Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System (Ministry of Education), School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093 (China); State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 Zhongshan North Road, Shanghai 200062 (China)

    2014-05-19

    Spectral filtering of an all-normal-dispersion Yb-doped fiber laser was demonstrated effective for broadband supercontinuum generation in the picosecond time region. The picosecond pump pulses were tailored in spectrum with 1 nm band-pass filter installed between two single-mode fiber amplifiers. By tuning the spectral filter around 1028 nm, four-wave mixing was initiated in a photonic crystal fiber spliced with single-mode fiber, as manifested by the simultaneous generation of Stokes wave at 1076 nm and anti-Stokes wave at 984 nm. Four-wave mixing took place in cascade with the influence of stimulated Raman scattering and eventually extended the output spectrum more than 900 nm of 10 dB bandwidth. This technique allows smooth octave supercontinuum generation by using simple single-mode fiber amplifiers rather than complicated multistage large-mode-area fiber amplifiers.

  3. Depolarization effect in rare-earth doped Y{sub 2}O{sub 3} films in blue and UV spectral range

    Energy Technology Data Exchange (ETDEWEB)

    Gasimov, Naghi; Mammadov, Eldar; Babayev, Sardar; Mamedova, Irada; Mamedov, Nazim [Department of Ellipsometry, Institute of Physics, Azerbaijan National Academy of Sciences, H. Javid ave. 33, Baku-1143 (Azerbaijan); Joudrier, Anne L.; Andriamiadamanana, Christian; Naghavi, Negar; Guillemoles, Jean F. [Institute for Research and Development of Photovoltaic Energy, 6 Quai Watier, 78401 Chatou, Paris (France)

    2015-06-15

    The 200 to 300 nm thick, Er and Er,Yb doped Y{sub 2}O{sub 3} films deposited onto silicon substrate by spin coating have been studied by spectroscopic ellipsometry over the 192-1680 nm spectral range at room temperature. All samples have been found to be strongly depolarizing in the blue and UV part of the spectrum. Complimentary examination of the sample surfaces, using confocal photoluminescence microscopy has disclosed the non-uniform distribution of the rare-earth dopants. The depolarization effects have then been modeled and found to be best reproduced by taking the thickness non-uniformity as the main source of depolarization. The optical constants of the studied films have been determined after four-step modeling with sequential decrease of the mean square error. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Developments of new laser crystals doped with Yb ions

    International Nuclear Information System (INIS)

    In the development of laser crystal suitable for the ultra high peak power CPA (Chirped Pulse Amplification) laser system with a compact size, fluoride YLF laser crystals doped with Yb3+ rare earth ion have been grown by a vertical Bridgman method. To prevent opaque crystal growth, one of growth materials, YF3 and PbF2 as a scavenger were mixed and heated twice in the vacuum furnace to get rid of YOF. We also adjusted the temperature gradient at the crystal growth surface and a mixing rate of the initial materials of LiF and YF3. As a result, Yb doped YLF crystal was successfully grown with the optimum temperature gradient of 30 - 40degC/cm, and the rate of 60:40 for LiF:YF3 in mol-%. (author)

  5. Optimal design of a high-power picosecond laser system using a dual-stage ytterbium-doped fibre amplifier

    International Nuclear Information System (INIS)

    An average power as high as 60 W with 73 W of pumping was achieved for an ytterbium-doped fibre-based dual-stage amplifier (MOFA) system seeded by a diode-pumped solid-state (DPSS) laser. The corresponding optical conversion efficiency is 80%. The laser system generates a steady pulse train with a pulse width of 11 ps at a repetition rate of 250 MHz or a peak power of 21.8 kW. Moreover, the output beam quality M2 ≈ 1.6. The length and pumping power for the Yb-doped fibres were optimized to suppress stimulated Raman scattering (SRS) and amplified spontaneous emission (ASE) while maintaining desirable output characteristics. (paper)

  6. High power burst-mode operated sub-nanosecond fiber laser based on 20/125 μm highly doped Yb fiber

    Science.gov (United States)

    Wei, Kaihua; Wu, Pinghui; Wen, Ruhua; Song, Jiangxin; Guo, Yan; Lai, Xiaomin

    2016-02-01

    A master oscillator power amplification (MOPA) structured high power sub-nanosecond fiber laser with pulse bunch output is experimentally demonstrated. The seed was a figure-of-eight structured mode-locked fiber laser with a pulse duration of 700 ps and a repetition rate of 2.67 MHz. The seed pulse via two cascaded fiber couplers was multiplied to a pulse bunch, which was composed of 6 sub-pulses. The multiplied pulses were pre-amplified to an average power of 1.5 W through a cladding-pumping fiber amplifier. The pre-amplified laser was further amplified using a 20/125 μm large mode area (LMA) Yb-doped fiber. The laser emitted from the power-amplifier had an average power of 36 W, and a slope efficiency of 72%.

  7. Efficient single-mode operation of a cladding-pumped ytterbium-doped helical-core fiber laser.

    Science.gov (United States)

    Wang, P; Cooper, L J; Sahu, J K; Clarkson, W A

    2006-01-15

    A novel approach to achieving robust single-spatial-mode operation of cladding-pumped fiber lasers with multimode cores is reported. The approach is based on the use of a fiber geometry in which the core has a helical trajectory within the inner cladding to suppress laser oscillation on higher-order modes. In a preliminary proof-of-principle study, efficient single-mode operation of a cladding-pumped ytterbium-doped helical-core fiber laser with a 30 microm diameter core and a numerical aperture of 0.087 has been demonstrated. The laser yielded 60.4 W of output at 1043 nm in a beam with M2 diode stack at 976 nm. The slope efficiency at pump powers well above threshold was approximately 84%, which compares favorably with the slope efficiencies achievable with conventional straight-core Yb-doped double-clad fiber lasers.

  8. High power L-band mode-locked fiber laser based on topological insulator saturable absorber.

    Science.gov (United States)

    Meng, Yichang; Semaan, Georges; Salhi, Mohamed; Niang, Alioune; Guesmi, Khmaies; Luo, Zhi-Chao; Sanchez, Francois

    2015-09-01

    We demonstrate a passive mode-locked Er:Yb doped double-clad fiber laser using a microfiber-based topological insulator (Bi(2)Se(3)) saturable absorber (TISA). By optimizing the cavity loss and output coupling ratio, the mode-locked fiber laser can operate in L-band with high average output power. With the highest pump power of 5 W, 91st harmonic mode locking of soliton bunches with average output power of 308 mW was obtained. This is the first report that the TISA based erbium-doped fiber laser operating above 1.6 μm and is also the highest output power yet reported in TISA based passive mode-locked fiber laser. PMID:26368409

  9. Pump-limited, 203 W, single-frequency monolithic fiber amplifier based on laser gain competition.

    Science.gov (United States)

    Zeringue, Clint; Vergien, Christopher; Dajani, Iyad

    2011-03-01

    We present high power results of a Yb-doped fiber amplifier seeded with a combination of broad and single-frequency laser signals. This two-tone concept was used in conjunction with externally applied or intrinsically formed thermal gradients to demonstrate combined stimulated Brillouin scattering suppression in a copumped monolithic, polarization-maintaining (PM) fiber. Depending on the input parameters and the thermal gradient, the output power of the single-frequency signal ranged from 80 to 203 W with slope efficiencies from 70% to 80%. The 203 W amplifier was pump limited and is, to the best of our knowledge, the highest reported in the literature for monolithic, PM single-frequency fiber amplifiers. PMID:21368926

  10. Design and analysis of spectral beam combining system for fiber lasers based on a concave grating

    Institute of Scientific and Technical Information of China (English)

    WU Zhuo-liang; ZHAO Shang-hong; CHU Xing-chun; ZHANG Xi; ZHAN Sheng-bao; MA Li-hua

    2012-01-01

    Anovel fiber laser spectral beam combining scheme based on a concave grating is presented.The principle of the presented system is analyzed,and a concave grating with blazed structure for spectral beam combining is designed.The combining potential of the system is analyzed,and the results show that 39 Yb-doped fiber laser can be spectrally beam combined via the designed system.By using scalar diffraction theory,the combining effect of the system is analyzed.The results show that the diffraction efficiency of the designed concave grating is higher than 72% over the whole gain bandwidth,and the combining efficiency is 73.4%.With output power of 1 kW for individual fiber laser,combined power of 28.6 kW can be achieved.

  11. 6-GHz, Kerr-lens mode-locked Yb:Lu2O3 ceramic laser for comb-resolved broadband spectroscopy.

    Science.gov (United States)

    Endo, Mamoru; Ozawa, Akira; Kobayashi, Yohei

    2013-11-01

    A laser diode (LD)-pumped, 6-GHz repetition rate, ytterbium (Yb)-doped Lu2O3 ceramic Kerr-lens mode-locked laser is described. A bow-tie ring cavity enabled the generation of femtosecond pulses centered at a wavelength of 1076 nm with an average power of 10 mW. The pulse duration after an amplifier was 161 fs whereas the transform-limited pulse duration directly from the oscillator was 148 fs. The repetition frequency was sufficiently high for each longitudinal mode to be spectrally resolved by a commercially available optical spectrum analyzer. The developed laser was successfully applied to the absorption spectroscopy of metastable helium4 and demonstrated the suitability of the system as a source for comb-resolved broadband spectroscopy. PMID:24177130

  12. Point defect stability in gamma irradiated aluminoborosilicate glasses: Influence of Yb{sup 3+} doping ions

    Energy Technology Data Exchange (ETDEWEB)

    Ollier, N., E-mail: nadege.ollier@polytechnique.edu [CEA, IRAMIS, Laboratoire des Solides Irradies, Ecole Polytechnique, CNRS, 91128 Palaiseau (France); Pukhkaya, V. [CEA, IRAMIS, Laboratoire des Solides Irradies, Ecole Polytechnique, CNRS, 91128 Palaiseau (France)

    2012-04-15

    Yb-doped aluminoborosilicate were irradiated with gamma rays at 10{sup 4}, 10{sup 5}, 10{sup 6} and 10{sup 7} Gy. The thermal stability as well as the recovery at room temperature of paramagnetic point defects such as Boron Oxygen Hole Center (BOHC), peroxy radicals and E Prime center were studied. At first, doping with Yb induced a saturation of the E Prime defect production and more importantly, the E Prime center recovering temperature was decreased by 50 Degree-Sign C. E Prime and BOHC defects both showed a limited stability at room temperature. By doping with Yb the glasses, the fading time of defects and in particular the BOHC defect recovery was modified. The BOHC defect showed moreover a larger sensitivity to photobleaching compared to the E Prime centers.

  13. A 23.75-GHz frequency comb with two low-finesse filtering cavities in series for high resolution spectroscopy

    Institute of Scientific and Technical Information of China (English)

    侯磊; 韩海年; 王薇; 张龙; 庞利辉; 李德华; 魏志义

    2015-01-01

    A laser frequency comb with several tens GHz level is demonstrated, based on an Yb-doped femtosecond fiber laser and two low-finesse Fabry–P´erot cavities (FPCs) in series. The original 250-MHz mode-line-spacing of the source comb is filtered to 4.75 GHz and 23.75 GHz, respectively. According to the multi-beam interferences theory of FPC, the side-mode suppression rate of FPC schemes is in good agreement with our own theoretical results from 27 dB of a single FPC to 43 dB of paired FPCs. To maintain long-term stable operation and determine the absolute frequency mode number in the 23.75-GHz comb, the Pound–Drever–Hall (PDH) locking technology is utilized. Such stable tens GHz frequency combs have important applications in calibrating astronomical spectrographs with high resolution.

  14. Observation of soliton explosions in a passively mode-locked fiber laser

    CERN Document Server

    Runge, Antoine F J; Erkintalo, Miro

    2014-01-01

    Soliton explosions are among the most exotic dissipative phenomena studied in mode-locked lasers. In this regime, a dissipative soliton circulating in the laser cavity experiences an abrupt structural collapse, but within a few roundtrips returns to its original quasi-stable state. In this work we report on the first observation of such events in a fiber laser. Specifically, we identify clear explosion signatures in measurements of shot-to-shot spectra of an Yb-doped mode-locked fiber laser that is operating in a transition regime between stable and noise-like emission. The comparatively long, all-normal-dispersion cavity used in our experiments also permits direct time-domain measurements, and we show that the explosions manifest themselves as abrupt temporal shifts in the output pulse train. Our experimental results are in good agreement with realistic numerical simulations based on an iterative cavity map.

  15. Generating 2 micron continuous-wave ytterbium-doped fiber laser-based optical parametric effect

    Science.gov (United States)

    Paul, M. C.; Latiff, A. A.; Hisyam, M. B.; Rusdi, M. F. M.; Harun, S. W.

    2016-10-01

    We report an efficient method for generating a 2 micron laser based on an optical parametric oscillator (OPO). It uses a long piece of a newly developed double-clad ytterbium-doped fiber (YDF), which is obtained by doping multi-elements of ZrO2, CeO2 and CaO in a phospho-alumina-silica glass as a gain medium. The efficient 2 micron laser generation is successful due to the presence of partially crystalline Yb-doped ZrO2 nano-particles that serve as a nonlinear material in a linear cavity configuration and high watt-level pump power. Stable self-wavelength double lasing at 2122 nm with an efficiency of 7.15% is successfully recorded. At a maximum pump power of 4.1 W, the output power is about 201 mW.

  16. Fifty-ps Raman fiber laser with hybrid active-passive mode locking.

    Science.gov (United States)

    Kuznetsov, A G; Kharenko, D S; Podivilov, E V; Babin, S A

    2016-07-25

    Actively mode locked Raman lasing in a ring PM-fiber cavity pumped by a linearly polarized Yb-doped fiber laser is studied. At co-propagating pumping, a stochastic pulse with duration defined by the AOM switching time (~15 ns) is generated with the round-trip period. At counter-propagating pumping, one or several sub-ns pulses (within the AOM switching envelope) are formed. It has been found that the formation of such stable multi-pulse structure is defined by the single-pulse energy limit (~20 nJ) set by the second-order Raman generation. Adding a NPE-based saturable absorber in the actively mode locked cavity, results in sufficient shortening of the generated pulses both in single- and multi-pulse regimes (down to 50 ps). A model is developed adequately describing the regimes. PMID:27464081

  17. Compression of chirp pulses from a femtosecond fiber based amplifier

    Science.gov (United States)

    Ito, Rumi; Takiuchi, Ken-ichi; Tei, Kazuyoku; Yamaguchi, Shigeru; Enokidani, Jyun; Sumida, Shin

    2015-03-01

    We demonstrate a single mode fiber based master oscillator power amplifier (MOPA) with a single polarization and a fully monolithic design. We have built a passive mode-locked polarization maintaining Yb doped fiber as the master oscillator contains a semiconductor saturable absorber mirror and a chirped fiber Bragg grating for the dispersion management. The net intracavity dispersion was managed to be slightly anomalous. The oscillator generates the 150 fs (sech2) pulses at the center wavelength of 1065 nm, and the repetition rate of 42 MHz. The oscillator output was amplified to 1.4 W from 80 mW in the single stage fiber amplifier which results in pulse shape distortion. The pulse shaping with a band pass filter and a compressor was applied to the amplified pulses. The shaping pulses have the pulse width of 90 fs and the pulse energy of 16 nJ.

  18. Hybrid master oscillator power amplifier system providing 10 mJ, 32 W, and 50 MW pulses for optical parametric chirped-pulse amplification pumping

    International Nuclear Information System (INIS)

    We present a high-energy, high-average-power picosecond laser system based on a hybrid chain in a master oscillator power amplifier configuration. The chain is seeded by a Ti:sapphire oscillator, followed by a Yb doped fiber preamplifier, a Nd:YAG-based regenerate amplifier, and a Nd:YVO4-based single-pass amplifier. The final diode-pumped, solid-state amplifier is detailed and produces pulses with more than 10 mJ energy at 32 W average power with 207 ps duration, corresponding to 50 MW peak power. The picosecond pulse output is seeded and optically synchronized with the sub-5-fs oscillator for optical parametric chirped-pulse amplification pumping. (authors)

  19. Experimental study on the all-fiberized continuous-wave ytterbium-doped laser operating near 980 nm.

    Science.gov (United States)

    Wang, Ruixing; Liu, Ying; Cao, Jianqiu; Guo, Shaofeng; Si, Lei; Chen, Jinbao

    2013-08-20

    All-fiberized continuous-wave Yb-doped fiber lasers operating near 980 nm are fabricated, and 1.73 W, 980 nm lasing is obtained. Moreover, the output properties of the 980 nm fiber laser are studied by experiment. It is demonstrated, for the first time to the best of our knowledge, that the output power curve versus the active fiber length experiences double-peak values, which are caused by the red shift of the lasing wavelength induced by the longitudinal-mode competition. It is also demonstrated that the pump threshold increases exponentially with the active fiber length. The relationship between the pump threshold and the optimum active fiber length is examined. PMID:24084992

  20. Nonlinear absorption of SWNT film and its effects to the operation state of pulsed fiber laser.

    Science.gov (United States)

    Li, Xiaohui; Wang, Yonggang; Wang, Yishan; Zhao, Wei; Yu, Xuechao; Sun, Zhipei; Cheng, Xueping; Yu, Xia; Zhang, Ying; Wang, Qi Jie

    2014-07-14

    We study a single-wall carbon nanotube (SWNT) Polyvinyl alcohol (PVA) composite as a saturable absorber (SA) for pulse generation in Yb-doped fiber lasers. The saturable absorption and optical limiting (OL) characteristics of the SWNT device are investigated. By combing these two nonlinear effects, we find out for the first time, to the best of our knowledge, that mode-locking can be obtained in the dissipative soliton regime at low pumping followed by Q-switching at high pumping, which is quite different from conventional pulse dynamic evolutions. The Q-switched state operating at higher pump powers is due to the OL effect. The inverted operating fiber laser can be applied in various potential applications such as versatile material processing, optical communication and radar system etc.

  1. Generation of 30-fs pulses from a diode-pumped graphene mode-locked Yb:CaYAlO4 laser

    CERN Document Server

    Ma, Jie; Ning, Kaijie; Xu, Xiaodong; Xie, Guoqiang; Qian, Liejia; Loh, Kian Ping; Tang, Dingyuan

    2015-01-01

    Stable 30 fs pulses centered at 1068 nm (less than 10 optical cycles) are demonstrated in a diode pumped Yb:CaYAlO4 laser by using high-quality chemical vapor deposited monolayer graphene as the saturable absorber. The mode locked 8.43 optical-cycle pulses have a spectral bandwidth of ~ 50 nm and a pulse repetition frequency of ~ 113.5 MHz. To our knowledge, this is the shortest pulse ever reported for graphene mode-locked lasers and mode-locked Yb-doped bulk lasers. Our experimental results demonstrate that graphene mode locking is a very promising practical technique to generate few-cycle optical pulses directly from a laser oscillator.

  2. The Improved Power of the Central Lobe in the Beam Combination and High Power Output

    Institute of Scientific and Technical Information of China (English)

    LIU Hou-Kang; WEI Yun-Rong; DONG Jing-Xing; LOU Qi-Hong; XUE Yu-Hao; LI Zhen; HE Bing; ZHOU Jun; DING Ya-Qian; JIAO Meng-Li; LIU Chi; QI Yun-Feng

    2012-01-01

    In order to increase the power fraction of the central lobe in the coherent beam combination of lasers in an array,the effects of the distance factor of near-field distribution on far-field interference patterns are calculated and demonstrated experimentally.An improved beam array of interwoven distribution is demonstrated to enable the power in the central lobe to reach 41%.An optimized mirror array is carefully designed to obtain a high duty ratio,which is up to 53.3% at a high power level.By using these optimized methods and designs,the passive phase locking of eight Yb-doped fiber amplifiers with ring cavities are obtained,and a pleasing interference pattern with 87% visibility is observed.The maximum coherent output power of the system is up to 1066 W.%In order to increase the power fraction of the central lobe in the coherent beam combination of lasers in an array, the effects of the distance factor of near-field distribution on far-field interference patterns are calculated and demonstrated experimentally. An improved beam array of interwoven distribution is demonstrated to enable the power in the central lobe to reach 41%. An optimized mirror array is carefully designed to obtain a high duty ratio, which is up to 53.3% at a high power level. By using these optimized methods and designs, the passive phase locking of eight Yb-doped fiber amplifiers with ring cavities are obtained, and a pleasing interference pattern with 87% visibility is observed. The maximum coherent output power of the system is up to 1066 W.

  3. Therapeutic effect of intravesical administration of paclitaxel solubilized with poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) in an orthotopic bladder cancer model

    International Nuclear Information System (INIS)

    To evaluate the effects of intravesical administration of paclitaxel (PTX-30W), which was prepared by solubilization with a water-soluble amphiphilic polymer composed of PMB30W, a copolymer of 2-methacryloyloxyethyl phosphorylcholine and n-butyl methacrylate, in an orthotopic bladder cancer model. The cytotoxicities of PMB30W were examined in MBT-2 cell cultures and the results were compared with those of the conventional paclitaxel solubilizer Cremophor. In an orthotopic MBT-2 bladder cancer model, the effect of intravesical administration of PTX-30W was compared with that of paclitaxel solubilized with Cremophor (PTX-CrEL). The paclitaxel concentration in bladder tumors after the intravesical treatment was also evaluated using liquid chromatography tandem mass spectrometry (LC-MS/MS) system. In vitro, Cremophor exhibited dose-dependent cytotoxicity towards MBT-2 cells, whereas no cytotoxicity was observed with PMB30W. In the orthotopic bladder cancer model, intravesical administration of PTX-30W resulted in a significant reduction of bladder wet weight compared with that of PTX-CrEL. The paclitaxel concentration in bladder tumors after the intravesical treatment was significantly higher in PTX-30W treated mice than in PTX-CrEL treated mice. Intravesically administered PTX-30W can elicit stronger antitumor effects on bladder tumors than conventional paclitaxel formulated in Cremophor, presumably because of its better penetration into tumor cells. PTX-30W might be a promising antitumor agent for intravesical treatment of non-muscle invasive bladder cancer

  4. Effect of sintering temperature on the morphology and mechanical properties of PTFE membranes as a base substrate for proton exchange membrane

    Directory of Open Access Journals (Sweden)

    Nor Aida Zubir

    2002-11-01

    Full Text Available This paper reports the development of PTFE membranes as the base substrates for producing proton exchange membrane by using radiation-grafting technique. An aqueous dispersion of PTFE, which includes sodium benzoate, is cast in order to form suitable membranes. The casting was done by usinga pneumatically controlled flat sheet membrane-casting machine. The membrane is then sintered to fuse the polymer particles and cooled. After cooling process, the salt crystals are leached from the membrane by dissolution in hot bath to leave a microporous structure, which is suitable for such uses as a filtration membrane or as a base substrate for radiation grafted membrane in PEMFC. The effects of sintering temperature on the membrane morphology and tensile strength were investigated at 350oC and 385oC by using scanning electron microscopy (SEM and EX 20, respectively. The pore size and total void space are significantly smaller at higher sintering temperature employed with an average pore diameter of 11.78 nm. The tensile strength and tensile strain of sintered PTFE membrane at 385oC are approximately 19.02 + 1.46 MPa and 351.04 + 23.13 %, respectively. These results were indicated at 385oC, which represents significant improvements in tensile strength and tensile strain, which are nearly twice those at 350oC.

  5. Analysis and evaluation of the power amplifier device

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y. K.; Ryu, J. W. [Kongju National University, Gongju (Korea, Republic of)

    2011-11-15

    We developed a master oscillator power amplifier (MOPA) type fiber amplifier for the separation of the Ca-48 isotope by using a fiber laser. The ytterbium (Yb)-doped end-capped rod-type photonic crystal fiber (PCF) was used as a gain medium of MOPA amplifier. The PCFs used in our experiments were a 56-cm and an 81-cm rod-type end-capped Yb-doped double-clad PM fibers 'DC-285/100-PM-Yb-Rod', with a 100-{mu}m core (NA 0.02) and a 285-{mu}m cladding (NA 0.6) fabricated by NKT Photonics. The mode field diameter (MFD) of the rod-type PCF was 75-{mu}m, and an absorption efficiency of 30 dB/m at 976 nm and a low NA 0.02 helped to sustain the excellent lasing beam quality. We obtained an output power of 112 W at a pump power of 380 W with a repetition rate of 150 kHz. The measured pulse width was 13 ns at 150 kHz, 1056 nm. The laser beam quality shows a single mode amplification characteristics with a beam quality factor values of M2 are 2 -3. The PCF launching efficiency reached a maximum value of 86.7% with an average efficiencies of above 80%. At a pump power of 250 W and seed power input of 4 W, the CW PCF amplifier was found to generate average output powers of 138 W, 110 W, and 82 W at 1056-nm, 1070-nm, and 1089-nm wavelengths, respectively. The amplified PCF output beam had a line width of 70 MHz full width at half maximum (FWHM). These PCF amplified beams had good beam qualities with M2values of less than 1.8 at all three wavelengths. The gain saturation seed input power in the 81-cm PCF was found to be {approx}6 W at 1056 nm. The temperature of the PCF core reached over 230 .deg. C at the pumping section of the PCF. The temperatures of the end-cap heads on both the pumping and the output end-cap sides were 81.4 .deg. C and 35.7 .deg. C, respectively. The PCF amplifier maintained good polarization mode characteristics with an average DOP of over 87%. The slight decrease in the DOP oat output powers over 170 W output power may have been caused by a

  6. Intense cooperative upconversion emission in Yb/Er: TeO{sub 2}–Li{sub 2}O–WO{sub 3} oxyfluoride glass ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Ansari, Ghizal F.; Mahajan, S.K., E-mail: sachin_k_mahajan@rediffmail.com

    2014-12-15

    Novel oxyfluoride glass ceramics based on Yb{sup 3+}-doped TeO{sub 2}–Li{sub 2}O–WO{sub 3}–ErF{sub 3} (TWLE) were prepared using the two-stage heat-treatment method. The structural characterisation of these materials with X-ray diffraction indicated that crystalline phases of LiYbErF{sub 4} nanocrystals grew in the glass ceramics. Upon excitation with a 980 nm laser diode the Yb{sup 3+} doped (2 mol%) TWLE glass-ceramic produced intense blue emission at 487 nm, weak green emission at 525 nm and 550 nm, and red emission at 650 nm at room temperature. The mechanism of the blue emission, which is attributed to cooperative upconversion from pairs of excited Yb{sup 3+} ions to ground-state Er{sup 3+} ions, and the weak red and green emissions, which are attributed to energy transfer from Yb{sup 3+} to Er{sup 3+} ions, were investigated. The results of a pump-power dependence measurement suggested that the blue cooperative emission is a two-photon process. A rate equation was used to describe the cooperative energy-transfer process among the donor and acceptor ions. The observed results were compared to the behavior of another glass materials that exhibits blue cooperative emission, revealing the considerable advantage of TWLE:2Yb glass ceramics for optical devices. - Highlights: • The transparent glass-ceamics based on Yb doped TeO{sub 2}–Li{sub 2}O–WO{sub 3}–ErF{sub 3} (TWLE) have been prepared. • XRD confirm crystalline phase of LiYbErF{sub 4} nanocrystals are grown in glass ceramics. • Under 980 nm LD excitation of TWLE:2Yb produced intense blue emission due to cooperative upconversion process exists. • Pump power excitation confirms cooperative upconvesion is two-photon process. • The quadratic dependence of pump intensity determined by mean of the rate equations. • Comparative studies of blue cooperative for TWLE:2Yb with other Yb doped materials described.

  7. Tunable pulse width and multi-megawatt peak-power pulses from a nonlinearly compressed monolithic fiber MOPA system

    Science.gov (United States)

    Yamashita, Ryutarou; Maeda, Kazuo; Watanabe, Goro; Tei, Kazuyoku; Yamaguchi, Shigeru; Enokidani, Jun; Sumida, Shin

    2016-03-01

    We report on tunable pulse width and high peak power pulse generation from a nonlinearly compressed monolithic fiber MOPA system. The master seed source employs a Mach-Zehnder intensity modulator (MZIM). This seed source has operational flexibility with respect to pulse width, 90 ps to 2 ns and repetition rate, 200 kHz to 2 MHz. The seed pulses are amplified by a monolithic three-stage amplifier system based on polarization maintain Yb-doped fibers. The maximum output power was 32 W at the shortest pulse condition, the pulse width of 90 ps and the repetition rate of 750 kHz. A spectral width after amplification was broadened to 0.73 nm at RMS width. Both of ASE and SRS are not observed in the spectrum. After amplification, we also demonstrated pulse compression with a small piece of chirped volume Bragg-grating (CVBG) which has the dispersion rate of 81 ps/nm. As a result of pulse compression, the shortest pulse width was reduced from 90 ps to 3.5 ps, which brought an increase of the peak power up to 3.2 MW. The compressed pulses are clean with little structure in their wings. We can expand the operation range of the monolithic fiber MOPA system in pulse width, 3.5 ps to 2 ns.

  8. (6+1) x1 fiber combiner based on thermally expanded core technique for high power amplifiers

    Science.gov (United States)

    Zhao, Ke; Chen, Zilun; Zhou, Xuanfeng; Wang, Zefeng; Jiang, Houman

    2015-07-01

    A high-efficiency pump-signal combiner for high power fiber amplifiers based on thermally expanded core (TEC) technique is reported in this paper. TEC technique is used to fabricate mode-field adapter which allows optimization of signal fibers in a monolithic (6+1) ×1 fiber combiner. The combiner is fabricated by connecting a tapered fiber bundle (TFB) to a passive 25/250 (NA=0.06/0.46) double-clad fiber (DCF). By this method, the coupling efficiency of SMF-28 signal fiber at 1064nm improves from 54% to 92.7%. The average pump coupling efficiencies of six 105/125 (NA=0.15) fibers are measured to be 96.7% at 976nm. Furthermore, the average signal transmission efficiency is around 93.3%. The fabricated fiber combiner is spliced to an Yb-doped DCF for use as an all-fiber amplifier. The slope efficiency is measured to be 71.6%.

  9. On the role of Yb as an impurity in the excitation of Er 3+ emission in silicon-rich silicon oxide

    Science.gov (United States)

    Kozanecki, A.; Kuritsyn, D.; Jantsch, W.

    2006-05-01

    The aim of this work is to check if Yb 3+ ions can be used as sensitizers for the 4I 13/2- 4I 15/2 emission of Er 3+ ions at 1.54 μm in silicon-rich silicon oxide (SRSO). To answer this question, photoluminescence excitation (PLE) experiments were performed on the Er 3+ emission in a wide range of excitation wavelengths. The PLE spectra in the 420-650 nm range were excited using an optical parametric oscillator. In Er + Yb implanted silica we found an absorption band related to Yb at wavelengths shorter than 530 nm. Radiation defects were excluded as absorbing species in this range of wavelengths. In SRSO PLE by Yb is entirely suppressed by absorption due to silicon nanoclusters. As a result we conclude that Yb doping of SRSO:Er does not improve the PL efficiency of Er 3+ in comparison with SRSO:Er. We interpret a sensitization mechanism by Yb in the UV-green range in terms of the Yb 2+ → Yb 3+ recharging process, in which an Yb ion becomes excited into its 2+ state, leaving a hole, hVB, localized near Yb 2+. Recombination with a hole leaves Yb 3+ in its 2F 5/2 excited state from which energy is very efficiently transferred to Er 3+ ions.

  10. Optimization of noncollinear optical parametric amplification

    Science.gov (United States)

    Schimpf, D. N.; Rothardt, J.; Limpert, J.; Tünnermann, A.

    2007-02-01

    Noncollinearly phase-matched optical parametric amplifiers (NOPAs) - pumped with the green light of a frequency doubled Yb-doped fiber-amplifier system 1, 2 - permit convenient generation of ultrashort pulses in the visible (VIS) and near infrared (NIR) 3. The broad bandwidth of the parametric gain via the noncollinear pump configuration allows amplification of few-cycle optical pulses when seeded with a spectrally flat, re-compressible signal. The short pulses tunable over a wide region in the visible permit transcend of frontiers in physics and lifescience. For instance, the resulting high temporal resolution is of significance for many spectroscopic techniques. Furthermore, the high magnitudes of the peak-powers of the produced pulses allow research in high-field physics. To understand the demands of noncollinear optical parametric amplification using a fiber pump source, it is important to investigate this configuration in detail 4. An analysis provides not only insight into the parametric process but also determines an optimal choice of experimental parameters for the objective. Here, the intention is to design a configuration which yields the shortest possible temporal pulse. As a consequence of this analysis, the experimental setup could be optimized. A number of aspects of optical parametric amplifier performance have been treated analytically and computationally 5, but these do not fully cover the situation under consideration here.

  11. Ultra-compact Watt-level flat supercontinuum source pumped by noise-like pulse from an all-fiber oscillator.

    Science.gov (United States)

    Chen, He; Zhou, Xuanfeng; Chen, Sheng-Ping; Jiang, Zong-Fu; Hou, Jing

    2015-12-28

    We demonstrate Watt-level flat visible supercontinuum (SC) generation in photonic crystal fibers, which is directly pumped by broadband noise-like pulses from an Yb-doped all-fiber oscillator. The novel SC generator is featured with elegant all-fiber-integrated architecture, high spectral flatness and high efficiency. Wide optical spectrum spanning from 500 nm to 2300 nm with 1.02 W optical power is obtained under the pump of 1.4 W noise-like pulse. The flatness of the spectrum in the range of 700 nm~1600 nm is less than 5 dB (including the pump residue). The exceptional simplicity, economical efficiency and the comparable performances make the noise-like pulse oscillator a competitive candidate to the widely used cascade amplified coherent pulse as the pump source of broadband SC. To the best of our knowledge, this is the first demonstration of SC generation which is directly pumped by an all-fiber noise-like pulse oscillator. PMID:26831958

  12. High-Nonlinearity Dispersion-Shifted Lead-Silicate Holey Fibers for Efficient 1-µm Pumped Supercontinuum Generation

    Science.gov (United States)

    Leong, J. Y. Y.; Petropoulos, P.; Price, J. H. V.; Ebendorff-Heidepriem, Heike; Asimakis, S.; Moore, R. C.; Frampton, K. E.; Finazzi, V.; Feng, X.; Monro, T. M.; Richardson, D. J.

    2006-01-01

    This paper reports on the recent progress in the design and fabrication of high-nonlinearity lead-silicate holey fibers (HFs). First, the fabrication of a fiber designed to offer close to the maximum possible nonlinearity per unit length in this glass type is described. A value of gamma = 1860 W-1 · km-1 at a wavelength of 1.55 µm is achieved, which is believed to be a record for any fiber at this wavelength. Second, the design and fabrication of a fiber with a slightly reduced nonlinearity but with dispersion-shifted characteristics tailored to enhance broadband supercontinuum (SC) generation when pumped at a wavelength of 1.06 µm-a wavelength readily generated using Yb-doped fiber lasers-are described. SC generation spanning more than 1000 nm is observed for modest pulse energies of sim 100 pJ using a short length of this fiber. Finally, the results of numerical simulations of the SC process in the proposed fibers are presented, which are in good agreement with the experimental observations and highlight the importance of accurate control of the zero-dispersion wavelength (ZDW) when optimizing such fibers for SC performance.

  13. Synthesis and down-conversion luminescence properties of Er3+/Yb3+ co-doped AlF3-PbF2-CaF2 powders

    Science.gov (United States)

    Liu, Fangchao; Han, Qun; Liu, Tiegen; Chen, Yaofei; Du, Yang; Yao, Yunzhi

    2015-08-01

    Er3+/Yb3+ co-doped oxy-fluoride powders with varying Er/Yb concentration were prepared by a melt quenching method at various sintering temperature. The effect of the Er/Yb doped concentration and sintering temperature were analyzed by using optical absorption and emission techniques. The Judd-Ofelt theory has been used to evaluate the three intensity parameters (Ωλ, where λ = 2, 4 and 6) and calculate the oscillator strengths (fc). Ultraviolet-to-visible emissions were observed under the excitation of a 325 nm CW laser. It was found that the down-conversion fluorescence intensity changes with the sintering temperature and Er/Yb content ratio, the results were explained with the level transitions in Er3+/Yb3+ co-doped systems. The intensity ratios (intensity of 437 nm as reference) of the luminescence spectra that the samples sintered at various temperature are relevant to Ω6 parameter which indicates the vibration amplitude of the Er-O distance. The sintering temperature also has an influence on the intensity ratios via affecting the thermalization of the excited 4I15/2 level.

  14. Structure and distortion of lead fluoride nanocrystals in rare earth doped oxyfluoride glass ceramics.

    Science.gov (United States)

    Ge, Jin; Zhao, Lijuan; Guo, Hui; Lan, Zijian; Chang, Lifen; Li, Yiming; Yu, Hua

    2013-10-28

    A series of rare earth (RE) doped oxyfluoride glasses with the composition of (45-x) SiO2-5Al2O3-40PbF2-10CdF2-xRe2O3 (x = 1, 5, 10, 15) (mol%) were prepared by a traditional melt-quenching method. Glass ceramics (GCs) were obtained after thermal treatment and characterized by X-ray diffraction (XRD) to investigate the nanocrystal structure and distortion. Both the dopant type and the doping level play an important role in the distortion of the PbF2-RE lattice. It is found that a cubic Pb3REF9 phase forms in low doping GCs, a tetragonal PbREF5 phase forms in middle doping GCs and cubic PbRE3F11 forms in high doping GCs. Accordingly, the site symmetry of RE(3+) dopants in β-PbF2 nanocrystal undergoes a transition of Oh···D4h···Oh with the increase of doping level. The change in the ligands coordinating the RE(3+) ions was further illustrated by the optical changes in Yb-doped GCs. This paper provides insights on the nanocrystal structure of RE at the atomic level and tries to make a complete description of the nanocrystal structure and distortion in these glass-ceramic materials, which will benefit the optimization of optical properties. PMID:24019159

  15. SESAM-modelocked Yb:CaF2 thin-disk-laser generating 285 fs pulses with 1.78 μJ of pulse energy

    Science.gov (United States)

    Dannecker, Benjamin; Abdou Ahmed, Marwan; Graf, Thomas

    2016-05-01

    We report on a SESAM-modelocked Yb:CaF2 thin-disk oscillator designed to generate more than 1 μJ of pulse energy at a moderate pulse repetition rate. The goal of our experiment was to explore the potential of Yb:CaF2 in a thin-disk laser (TDL) architecture for high power at pulse durations shorter than 300 fs as compared to other Yb-doped crystals exhibiting broad gain bandwidth. At a repetition rate of 10 MHz the laser produced an average output power of up to 17.8 W (1.78 μJ of pulse energy) with a beam quality factor M 2 below 1.2. The pulse duration was measured to be 285 fs, which results in a peak power of 5.5 MW. To the best of our knowledge, this is the highest pulse energy and peak power demonstrated to date with sub-300 fs pulses generated by SESAM-modelocked oscillators, leading to the conclusion that Yb:CaF2 is a very promising crystal for TDL technology.

  16. Fiber-optic thermometer application of thermal radiation from rare-earth end-doped SiO2 fiber

    International Nuclear Information System (INIS)

    Visible light thermal radiation from SiO2 glass doped with Y, La, Ce, Pr, Nd, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu were studied for the fiber-optic thermometer application based on the temperature dependence of thermal radiation. Thermal radiations according to Planck's law of radiation are observed from the SiO2 fibers doped with Y, La, Ce, Pr, Eu, Tb, and Lu at the temperature above 1100 K. Thermal radiations due to f-f transitions of rare-earth ions are observed from the SiO2 fibers doped with Nd, Dy, Ho, Er, Tm, and Yb at the temperature above 900 K. Peak intensities of thermal radiations from rare-earth doped SiO2 fibers increase sensitively with temperature. Thermal activation energies of thermal radiations by f-f transitions seen in Nd, Dy, Ho, Er, Tm, and Yb doped SiO2 fibers are smaller than those from SiO2 fibers doped with Y, La, Ce, Pr, Eu, Tb, and Lu. Thermal radiation due to highly efficient f-f transitions in Nd, Dy, Ho, Er, Tm, and Yb ions emits more easily than usual thermal radiation process. Thermal radiations from rare-earth doped SiO2 are potentially applicable for the fiber-optic thermometry above 900 K

  17. Fiber laser pumped burst-mode operated picosecond mid-infrared laser

    Institute of Scientific and Technical Information of China (English)

    魏凯华; 姜培培; 吴波; 陈滔; 沈永行

    2015-01-01

    We demonstrate a compact periodically poled MgO-doped lithium niobate (MgO:PPLN)-based optical parametric oscillator (OPO) quasi-synchronously pumped by a fiber laser system with burst-mode operation. The pump source is a peak-power-selectable pulse-multiplied picosecond Yb fiber laser. The chirped pulses from a figure of eight-cavity mode-locked fiber laser seed are narrowed to a duration of less than 50 ps using an FBG refl ector and a circulator. The narrowed pulses are directed to pass through a pulse multiplier and to form pulse bunches, each of which is composed of 13 sub-pulses. The obtained pulse bunches are amplified by two-stage fiber pre-amplifiers:one-stage is core-pumped and the other is cladding-pumped. A fiberized acousto–optic modulator is inserted to control the pulse repetition rate (PRR) of the pulse bunches before they are power-amplified in the final amplifier stage with a large mode area (LMA) PM Yb-doped fiber. The maximum average powers from the final amplifier are 85 W, 60 W, and 45 W respectively, corresponding to the PRR of 2.72 MHz, 1.36 MHz, and 0.68 MHz. The amplified pulses are directed to pump an MgO:PPLN-based optical parametric oscillator (OPO). A maximum peak power at 3.45 µm is obtained approximately to be 8.4 kW. Detailed performance characteristics are presented.

  18. Broadband Continuous-Wave Multi-Harmonic Optical Comb Based on a Frequency Division-by-Three Optical Parametric Oscillator

    Directory of Open Access Journals (Sweden)

    Yen-Yin Lin

    2014-11-01

    Full Text Available We report a multi-watt broadband continuous-wave multi-harmonic optical comb based on a frequency division-by-three singly-resonant optical parametric oscillator. This cw optical comb is frequency-stabilized with the help of a beat signal derived from the signal and frequency-doubled idler waves. The measured frequency fluctuation in one standard deviation is ~437 kHz. This is comparable to the linewidth of the pump laser which is a master-oscillator seeded Yb:doped fiber amplifier at ~1064 nm. The measured powers of the fundamental wave and the harmonic waves up to the 6th harmonic wave are 1.64 W, 0.77 W, 3.9 W, 0.78 W, 0.17 W, and 0.11 W, respectively. The total spectral width covered by this multi-harmonic comb is ~470 THz. When properly phased, this multi-harmonic optical comb can be expected to produce by Fourier synthesis a light source consisting of periodic optical field waveforms that have an envelope full-width at half-maximum of 1.59 fs in each period.

  19. Understanding the High Ionic Conductivity in Nanostructured Ytterbium Stabilized Zirconia Thin Films

    Directory of Open Access Journals (Sweden)

    A. Benítez-Rico

    2015-01-01

    Full Text Available Recently, high ionic conduction has been reported in nanostructured materials. This increase in conductivity can be important in technological applications, including micro-Solid Oxide Fuel Cells, so the understanding of this phenomenon is essential. In this work, XRD, Raman spectroscopy, SEM, EDS maps, and UV-Visible spectroscopy measurements are used to have an insight into the relationship between structural and electrical properties in nanostructured ytterbium stabilized zirconia (YbSZ thin films prepared by ultrasonic spray pyrolysis. Raman measurements allowed the identification of a mixture of tetragonal and cubic phases at 4% of Yb doping, which cannot be detected by XRD, while the compositional maps suggest that Yb can be located preferentially in the grain boundaries. Changes in the activation energy values in bulk and grain boundaries are related to the small grain sizes (≤10 nm. UV measurements support the ionic nature of the charge transport. These results indicate that the high conductivity is a consequence of different physical parameters in the films such as stress in the materials, different crystalline phases, impurities diffusion to the grain boundaries, and the presence or absence of electronic conduction. A model that explains the increase of conductivity in nanostructured materials must include all these aspects.

  20. Glass-on-Glass Fabrication of Bottle-Shaped Tunable Microlasers and their Applications.

    Science.gov (United States)

    Ward, Jonathan M; Yang, Yong; Nic Chormaic, Síle

    2016-01-01

    We describe a novel method for making microbottle-shaped lasers by using a CO2 laser to melt Er:Yb glass onto silica microcapillaries or fibres. This is realised by the fact that the two glasses have different melting points. The CO2 laser power is controlled to flow the doped glass around the silica cylinder. In the case of a capillary, the resulting geometry is a hollow, microbottle-shaped resonator. This is a simple method for fabricating a number of glass whispering gallery mode (WGM) lasers with a wide range of sizes on a single, micron-scale structure. The Er:Yb doped glass outer layer is pumped at 980 nm via a tapered optical fibre and WGM lasing is recorded around 1535 nm. This structure facilitates a new way to thermo-optically tune the microlaser modes by passing gas through the capillary. The cooling effect of the gas flow shifts the WGMs towards shorter wavelengths and thermal tuning of the lasing modes over 70 GHz is achieved. Results are fitted using the theory of hot wire anemometry, allowing the flow rate to be calibrated with a flow sensitivity as high as 72 GHz/sccm. Strain tuning of the microlaser modes by up to 60 GHz is also demonstrated. PMID:27121151

  1. Laser Design for Next Generation Compton Scattering Source at LLNL

    Science.gov (United States)

    Shverdin, Miro; Albert, Felicie; Anderson, Scott; Bayramian, Andy; Betts, Shawn; Cross, Rick; Ebbers, Chris; Gibson, David; Marsh, Roark; Messerly, Michael; Hartemann, Fred; Scarpetti, Ray; Siders, Craig; Barty, Chris

    2010-11-01

    We describe laser systems designed for the next generation Mono-Energetic Gamma-Ray (MEGa-ray) Compton scattering light source at LLNL. An 80 fs Yb:doped fiber oscillator seeds a photogun drive laser (PDL) and a high energy interaction system laser (ILS). Utilizing chirped pulse amplification (CPA) in fiber, the PDL will generate 80 μJ, spatially and temporally shaped pulses at 263 nm at 120 Hz precisely synchronized to the linac RF. The PDL system employs large mode photonic bandgap fibers and large area multi-layer dielectric gratings to generate over 1mJ per pulse with high recompression fidelity prior to frequency quadrupling. The high energy, 120 W ILS utilizes (CPA) in Nd:YAG to amplify a sub-nanometer bandwidth 20 μJ pulses from a fiber system to 1 J. A novel pulse stretcher provides a dispersion of over 7000 ps/nm to expand a several picosecond wide seed pulse to 6 ns. After amplification, the pulse is recompressed to 10 ps with a hyper-dispersive pulse compressor. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  2. Power scaling analysis of fiber lasers and amplifiers based on non-silica materials

    Science.gov (United States)

    Dawson, Jay W.; Messerly, Michael J.; Heebner, John E.; Pax, Paul H.; Sridharan, Arun K.; Bullington, Amber L.; Beach, Raymond J.; Siders, Craig W.; Barty, C. P. J.; Dubinskii, Mark

    2010-04-01

    A developed formalism1 for analyzing the power scaling of diffraction limited fiber lasers and amplifiers is applied to a wider range of materials. Limits considered include thermal rupture, thermal lensing, melting of the core, stimulated Raman scattering, stimulated Brillouin scattering, optical damage, bend induced limits on core diameter and limits to coupling of pump diode light into the fiber. For conventional fiber lasers based upon silica, the single aperture, diffraction limited power limit was found to be 36.6kW. This is a hard upper limit that results from an interaction of the stimulated Raman scattering with thermal lensing. This result is dependent only upon physical constants of the material and is independent of the core diameter or fiber length. Other materials will have different results both in terms of ultimate power out and which of the many limits is the determining factor in the results. Materials considered include silica doped with Tm and Er, YAG and YAG based ceramics and Yb doped phosphate glass. Pros and cons of the various materials and their current state of development will be assessed. In particular the impact of excess background loss on laser efficiency is discussed.

  3. Fiber-comb-stabilized light source at 556 nm for magneto-optical trapping of ytterbium

    CERN Document Server

    Yasuda, Masami; Inaba, Hajime; Nakajima, Yoshiaki; Hosaka, Kazumoto; Onae, Atsushi; Hong, Feng-Lei

    2010-01-01

    A frequency-stabilized light source emitting at 556 nm is realized by frequency-doubling a 1112-nm laser, which is phase-locked to a fiber-based optical frequency comb. The 1112-nm laser is either an ytterbium (Yb)-doped distributed feedback fiber laser or a master-slave laser system that uses an external cavity diode laser as a master laser. We have achieved the continuous frequency stabilization of the light source over a five-day period. With the light source, we have completed the second-stage magneto-optical trapping (MOT) of Yb atoms using the 1S0 - 3P1 intercombination transition. The temperature of the ultracold atoms in the MOT was 40 uK when measured using the time-of-flight method, and this is sufficient for loading the atoms into an optical lattice. The fiber-based frequency comb is shown to be a useful tool for controlling the laser frequency in cold-atom experiments.

  4. Kilowatt high-efficiency narrow-linewidth monolithic fiber amplifier operating at 1034 nm

    Science.gov (United States)

    Naderi, Nader A.; Flores, Angel; Anderson, Brian M.; Rowland, Ken; Dajani, Iyad

    2016-03-01

    Power scaling investigation of a narrow-linewidth, Ytterbium-doped all-fiber amplifier operating at 1034 nm is presented. Nonlinear stimulated Brillouin scattering (SBS) effects were suppressed through the utilization of an external phase modulation technique. Here, the power amplifier was seeded with a spectrally broadened master oscillator and the results were compared using both pseudo-random bit sequence (PRBS) and white noise source (WNS) phase modulation formats. By utilizing an optical band pass filter as well as optimizing the length of fiber used in the pre-amplifier stages, we were able to appreciably suppress unwanted amplified spontaneous emission (ASE). Notably, through PRBS phase modulation, greater than two-fold enhancement in threshold power was achieved when compared to the WNS modulated case. Consequently, by further optimizing both the power amplifier length and PRBS pattern at a clock rate of 3.5 GHz, we demonstrated 1 kilowatt of power with a slope efficiency of 81% and an overall ASE content of less than 1%. Beam quality measurements at 1 kilowatt provided near diffraction-limited operation (M2 knowledge, the power scaling results achieved in this work represent the highest power reported for a spectrally narrow all-fiber amplifier operating at < 1040 nm in Yb-doped silica-based fiber.

  5. Study of ytterbium doping effects on structural, mechanical and opto-thermal properties of sprayed ZnO thin films using the Boubaker Polynomials Expansion Scheme (BPES)

    Energy Technology Data Exchange (ETDEWEB)

    Amlouk, A. [Unite de physique des dispositifs a semi-conducteurs, Faculte des sciences de Tunis, Universite de Tunis El Manar, 2092 Tunis (Tunisia); Boubaker, K., E-mail: mmbb11112000@yahoo.f [Unite de physique des dispositifs a semi-conducteurs, Faculte des sciences de Tunis, Universite de Tunis El Manar, 2092 Tunis (Tunisia); Amlouk, M. [Unite de physique des dispositifs a semi-conducteurs, Faculte des sciences de Tunis, Universite de Tunis El Manar, 2092 Tunis (Tunisia); Bouhafs, M. [Unite de Recherche MA2I, Ecole Nationale d' Ingenieurs de Tunis, B.P. 37 Le Belvedere, 1002 Tunis (Tunisia)

    2009-10-19

    In this work, ZnO thin films have been grown on glass substrates by using a solution of propanol (C{sub 3}H{sub 8}O), water (H{sub 2}O) and zinc acetate (Z{sub n}(CH{sub 3}CO{sub 2}){sub 2}) in acidified medium (pH 5). The obtained films were n doped with ytterbium (Yb) at the rates of 100, 200 and 300 ppm. The structural features of the doped films were investigated using XRD, atomic force microscopy and scanning electronic microscopy techniques. XRD analysis shows a strong (0 0 2) X-ray diffraction line for increasing Yb-doping amounts. This c-axis preferential orientation of ZnO crystallites is naturally required to use this oxide as transparent conductor in optoelectronic applications. Atomic force microscopy (AFM) analysis shows an enhancement in the surface roughness of the doped ZnO:Yb thin films. Optical measurements were performed in 300-1800 nm domain via transmittance T(lambda) and reflectance R(lambda) spectra. Conjoint optical and thermal properties were deduced from the optical measurements in reference to the Amlouk-Boubaker opto-thermal expansivity psi{sub AB}. Optically relevant ytterbium doping effects have been discussed. Finally, mechanical measurements have been carried out using Vickers standard disposal. The results confirmed the structural and functional changes that several recent studies attributed to ytterbium doping.

  6. Gigahertz Self-referenceable Frequency Comb from a Semiconductor Disk Laser

    CERN Document Server

    Zaugg, Christian A; Mangold, Mario; Mayer, Aline S; Link, Sandro M; Emaury, Florian; Golling, Matthias; Gini, Emilio; Saraceno, Clara J; Tilma, Bauke W; Keller, Ursula

    2014-01-01

    We present a 1.75-GHz self-referenceable frequency comb from a vertical external-cavity surface-emitting laser (VECSEL) passively modelocked with a semiconductor saturable absorber mirror (SESAM). The VECSEL delivers 231-fs pulses with an average power of 100 mW and is optimized for stable and reliable operation. The optical spectrum was centered around 1038 nm and nearly transform-limited with a full width half maximum (FWHM) bandwidth of 5.5 nm. The pulses were first amplified to an average power of 5.5 W using a backward-pumped Yb-doped double-clad large mode area (LMA) fiber and then compressed to 85 fs with 2.2 W of average power with a passive LMA fiber and transmission gratings. Subsequently, we launched the pulses into a highly nonlinear photonic crystal fiber (PCF) and generated a coherent octave-spanning supercontinuum (SC). We then detected the carrier-envelope offset (CEO) frequency (fCEO) beat note using a standard f-to-2f-interferometer. The fCEO exhibits a signal-to-noise ratio of 17 dB in a 10...

  7. SBS mitigation with 'two-tone' amplification: a theoretical model

    Science.gov (United States)

    Bronder, T. J.; Shay, T. M.; Dajani, I.; Gavrielides, A.; Robin, C. A.; Lu, C. A.

    2008-02-01

    A new technique for mitigating stimulated Brillouin scattering (SBS) effects in narrow-linewidth Yb-doped fiber amplifiers is demonstrated with a model that reduces to solving an 8×8 system of coupled nonlinear equations with the gain, SBS, and four-wave mixing (FMW) incorporated into the model. This technique uses two seed signals, or 'two-tones', with each tone reaching its SBS threshold almost independently and thus increasing the overall threshold for SBS in the fiber amplifier. The wavelength separation of these signals is also selected to avoid FWM, which in this case possesses the next lowest nonlinear effects threshold. This model predicts an output power increase of 86% (at SBS threshold with no signs of FWM) for a 'two-tone' amplifier with seed signals at 1064nm and 1068nm, compared to a conventional fiber amplifier with a single 1064nm seed. The model is also used to simulate an SBS-suppressing fiber amplifier to test the regime where FWM is the limiting factor. In this case, an optimum wavelength separation of 3nm to 10nm prevents FWM from reaching threshold. The optimum ratio of the input power for the two seed signals in 'two-tone' amplification is also tested. Future experimental verification of this 'two-tone' technique is discussed.

  8. Single-mode operation of a coiled multimode fiber amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey P. Koplow; Dahv A. V. Kliner; Lew Goldberg

    2000-01-19

    The authors report a new approach to obtain single-transverse-mode operation of a multimode fiber amplifier, in which the gain fiber is coiled to induce significant bend loss for all but the lowest-order mode. They have demonstrated this method by constructing a coiled amplifier using Yb-doped, double-clad fiber with a core diameter of 25 {micro}m and NA of {minus}0.1 (V {approx} 7.4). When operated as an ASE source, the output beam had an M{sup 2} value of 1.09 {+-} 0.09; when seeded at 1,064 nm, the slope efficiency was similar to that of an uncoiled amplifier. This technique does not require exotic fiber designs or increase system complexity and is inexpensive to implement. It will allow scaling of pulsed fiber lasers and amplifiers to significantly higher pulse energies and peak powers and cw fiber sources to higher average powers while maintaining excellent beam quality.

  9. Multi-mJ, kHz, ps deep-ultraviolet source.

    Science.gov (United States)

    Chang, Chun-Lin; Krogen, Peter; Liang, Houkun; Stein, Gregory J; Moses, Jeffrey; Lai, Chien-Jen; Siqueira, Jonathas P; Zapata, Luis E; Kärtner, Franz X; Hong, Kyung-Han

    2015-02-15

    We demonstrate a 0.56-GW, 1-kHz, 4.2-ps, 2.74-mJ deep-ultraviolet (DUV) laser at ∼257.7  nm with a beam propagation factor (M2) of ∼2.54 from a frequency-quadrupled cryogenic multi-stage Yb-doped chirped-pulse amplifier. The frequency quadrupling is achieved using LiB3O5 and β-BaB2O4 crystals for near-infrared (NIR)-to-green and green-to-DUV conversion, respectively. An overall NIR-to-DUV efficiency of ∼10% has been achieved, which is currently limited by the thermal-induced phase mismatching and the DUV-induced degradation of transmittance. To the best of our knowledge, this is the highest peak-power picosecond DUV source from a diode-pumped solid-state laser operating at kHz repetition rates. PMID:25680176

  10. Growth, structural and spectroscopic properties of Yb{sup 3+}-doped Li{sub 0.75}Gd{sub 0.75}Ba{sub 0.5}(MoO{sub 4}){sub 2} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Cortes, A. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, c/ Sor Juana Ines de la Cruz, 3, Cantoblanco, 28049 Madrid (Spain); Cascales, C. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, c/ Sor Juana Ines de la Cruz, 3, Cantoblanco, 28049 Madrid (Spain)], E-mail: ccascales@icmm.csic.es; Zaldo, C. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, c/ Sor Juana Ines de la Cruz, 3, Cantoblanco, 28049 Madrid (Spain)], E-mail: cezaldo@icmm.csic.es

    2008-01-15

    Yb-doped Li{sub 0.75}Gd{sub 0.75}Ba{sub 0.5}(MoO{sub 4}){sub 2} crystals were grown in air by the Top Seeded Solution Growth slow cooling method in a Li{sub 2}Mo{sub 2}O{sub 7} flux. The single crystal X-ray diffraction analysis indicates the symmetry of monoclinic space group C2/c (No. 15), with lattice parameters a = 5.2355(3) A, b = 12.7396(8) A, c = 19.1626(11) A, {beta} = 91.170(1) deg., V = 1277.84(13) A{sup 3}, and Z = 8, with one 8f site shared (0.725:0.06:0.215) by Gd{sup 3+}, Yb{sup 3+} and Li{sup +} ions, respectively. The optical absorption and photoluminescence properties are described consistently with the anisotropic character of the monoclinic phase. The relative energies of the Yb{sup 3+} Stark levels have been determined, and in order to make a preliminary evaluation of its laser properties, values of the 300 K absorption and emission cross-sections have been derived.

  11. Ultra-compact Watt-level flat supercontinuum source pumped by noise-like pulse from an all-fiber oscillator.

    Science.gov (United States)

    Chen, He; Zhou, Xuanfeng; Chen, Sheng-Ping; Jiang, Zong-Fu; Hou, Jing

    2015-12-28

    We demonstrate Watt-level flat visible supercontinuum (SC) generation in photonic crystal fibers, which is directly pumped by broadband noise-like pulses from an Yb-doped all-fiber oscillator. The novel SC generator is featured with elegant all-fiber-integrated architecture, high spectral flatness and high efficiency. Wide optical spectrum spanning from 500 nm to 2300 nm with 1.02 W optical power is obtained under the pump of 1.4 W noise-like pulse. The flatness of the spectrum in the range of 700 nm~1600 nm is less than 5 dB (including the pump residue). The exceptional simplicity, economical efficiency and the comparable performances make the noise-like pulse oscillator a competitive candidate to the widely used cascade amplified coherent pulse as the pump source of broadband SC. To the best of our knowledge, this is the first demonstration of SC generation which is directly pumped by an all-fiber noise-like pulse oscillator.

  12. High pulse energy femtosecond large-mode-area photonic crystal fiber laser

    Institute of Scientific and Technical Information of China (English)

    SONG YouJian; HU MingLie; ZHANG Chi; CHAI Lu; WANG ChingYue

    2008-01-01

    A high pulse energy femtosecond fiber laser based on a large-mode-area photonic crystal fiber is demonstrated. A segment of Yb-doped single-polarization large-mode-area photonic crystal fiber with extremely low nonlinearity is explored as gain media of this fiber laser, resulting in intrinsically environmentally stability. The fiber laser is based on a linear cavity with dispersion compensation free configuration, and the stable mode-locking is obtained by a semiconductor saturable absorber mirror (SESAM). The fiber laser directly generates 2.5 W of average power at a repetition rate of 51.4 MHz,corresponding to a single pulse energy of 50 nJ. The output pulse duration is 4.2 ps, which is dechirped to 410 fs after extracavity dispersion compensation. The nonlinear absorption of SESAM determines the pulse shaping at low output power, while the mode-locking mechanism is under the balance between spectrum broadening from self-phase-modulation and gain filtering at the high output power.

  13. Fiber-optic thermometer application of thermal radiation from rare-earth end-doped SiO{sub 2} fiber

    Energy Technology Data Exchange (ETDEWEB)

    Katsumata, Toru, E-mail: katsumat@toyo.jp; Morita, Kentaro; Komuro, Shuji; Aizawa, Hiroaki [Faculty of Science and Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan)

    2014-08-15

    Visible light thermal radiation from SiO{sub 2} glass doped with Y, La, Ce, Pr, Nd, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu were studied for the fiber-optic thermometer application based on the temperature dependence of thermal radiation. Thermal radiations according to Planck's law of radiation are observed from the SiO{sub 2} fibers doped with Y, La, Ce, Pr, Eu, Tb, and Lu at the temperature above 1100 K. Thermal radiations due to f-f transitions of rare-earth ions are observed from the SiO{sub 2} fibers doped with Nd, Dy, Ho, Er, Tm, and Yb at the temperature above 900 K. Peak intensities of thermal radiations from rare-earth doped SiO{sub 2} fibers increase sensitively with temperature. Thermal activation energies of thermal radiations by f-f transitions seen in Nd, Dy, Ho, Er, Tm, and Yb doped SiO{sub 2} fibers are smaller than those from SiO{sub 2} fibers doped with Y, La, Ce, Pr, Eu, Tb, and Lu. Thermal radiation due to highly efficient f-f transitions in Nd, Dy, Ho, Er, Tm, and Yb ions emits more easily than usual thermal radiation process. Thermal radiations from rare-earth doped SiO{sub 2} are potentially applicable for the fiber-optic thermometry above 900 K.

  14. New insights on P-related paramagnetic point defects in irradiated phosphate glasses: Impact of glass network type and irradiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Pukhkaya, V.; Ollier, N., E-mail: nadege.ollier@polytechnique.edu [Laboratoire des Solides Irradiés, UMR 7642 CEA-CNRS-Ecole Polytechnique, Palaiseau (France); Trompier, F. [Institut de Radioprotection et de Sûreté Nucléaire DRPH/SDE/LDRI, Fontenay-aux-roses (France)

    2014-09-28

    P-related paramagnetic point defects were studied in irradiated Yb-doped phosphate glasses by electron paramagnetic resonance spectroscopy (X and Q-bands). A strong impact of the glass network type on the defect nature is shown. In all glasses, r-POHC defects formation is in strong correlation with Q{sup 2} tetrahedra amount supporting the structure of r-POHC. Ultra-phosphate glasses contain the larger defect type: Peroxy radicals, P{sub 1}, P{sub 2}, and P{sub 4} defects whose formation is linked to Q{sup 3} tetrahedra presence. In meta-phosphate and poly-phosphate glasses, peroxy radicals appear with r-POHC thermal recovery. In meta-phosphate glasses, a combination of P{sub 1} and P{sub 3} defects was evidenced for the first time, whereas in poly-phosphate glasses, only P{sub 3} defects were identified. Dose effect as well as defect recovery were analyzed.

  15. High repetition rate femtosecond laser forming sub-10 µm diameter interconnection vias

    Science.gov (United States)

    Tan, B; Panchatsharam, S; Venkatakrishnan, K

    2009-03-01

    Laser ablative microvia formation has been widely accepted as an effective manufacturing method for interconnect via formation. Current conventional nanosecond laser microvia formation has reached its limit in terms of minimum via diameter and machining quality. Femtosecond laser has been investigated intensively for its superior machining quality and capability of producing much smaller features. However, the traditional femtosecond laser has very low power and is thus unable to meet the throughput requirement. In this paper we report ablative microvia formation using femtosecond lasers at megahertz repetition rates. Laser ablation was demonstrated for the first time for sub-10 µm interconnection via drilling at a throughput of 10 000 vias per second. A systematic study of the influence of a high repetition rate in femtosecond laser micromachining of silicon was carried out. The experiments were performed using an Yb-doped fibre amplified/oscillator laser with 1030 nm wavelength in an air environment. The effects of a high repetition rate on microvia formation were observed at ~300 fs for silicon substrates. Laser parameters along with threshold energy, via diameter, ablation depth, ablation rate and via quality were studied in detail to accentuate the need of femtosecond lasers for forming sub-10 µm diameter microvias. The experimental results show that femtosecond laser pulses with high repetition rates show unequivocally the advantages of short-pulse laser ablation for high-precision applications in micrometre-scale dimensions.

  16. High repetition rate femtosecond laser forming sub-10 μm diameter interconnection vias

    International Nuclear Information System (INIS)

    Laser ablative microvia formation has been widely accepted as an effective manufacturing method for interconnect via formation. Current conventional nanosecond laser microvia formation has reached its limit in terms of minimum via diameter and machining quality. Femtosecond laser has been investigated intensively for its superior machining quality and capability of producing much smaller features. However, the traditional femtosecond laser has very low power and is thus unable to meet the throughput requirement. In this paper we report ablative microvia formation using femtosecond lasers at megahertz repetition rates. Laser ablation was demonstrated for the first time for sub-10 μm interconnection via drilling at a throughput of 10 000 vias per second. A systematic study of the influence of a high repetition rate in femtosecond laser micromachining of silicon was carried out. The experiments were performed using an Yb-doped fibre amplified/oscillator laser with 1030 nm wavelength in an air environment. The effects of a high repetition rate on microvia formation were observed at ∼300 fs for silicon substrates. Laser parameters along with threshold energy, via diameter, ablation depth, ablation rate and via quality were studied in detail to accentuate the need of femtosecond lasers for forming sub-10 μm diameter microvias. The experimental results show that femtosecond laser pulses with high repetition rates show unequivocally the advantages of short-pulse laser ablation for high-precision applications in micrometre-scale dimensions.

  17. Glass-on-Glass Fabrication of Bottle-Shaped Tunable Microlasers and their Applications

    Science.gov (United States)

    Ward, Jonathan M.; Yang, Yong; Nic Chormaic, Síle

    2016-04-01

    We describe a novel method for making microbottle-shaped lasers by using a CO2 laser to melt Er:Yb glass onto silica microcapillaries or fibres. This is realised by the fact that the two glasses have different melting points. The CO2 laser power is controlled to flow the doped glass around the silica cylinder. In the case of a capillary, the resulting geometry is a hollow, microbottle-shaped resonator. This is a simple method for fabricating a number of glass whispering gallery mode (WGM) lasers with a wide range of sizes on a single, micron-scale structure. The Er:Yb doped glass outer layer is pumped at 980 nm via a tapered optical fibre and WGM lasing is recorded around 1535 nm. This structure facilitates a new way to thermo-optically tune the microlaser modes by passing gas through the capillary. The cooling effect of the gas flow shifts the WGMs towards shorter wavelengths and thermal tuning of the lasing modes over 70 GHz is achieved. Results are fitted using the theory of hot wire anemometry, allowing the flow rate to be calibrated with a flow sensitivity as high as 72 GHz/sccm. Strain tuning of the microlaser modes by up to 60 GHz is also demonstrated.

  18. High efficiency fourth-harmonic generation from nanosecond fiber master oscillator power amplifier

    Science.gov (United States)

    Mu, Xiaodong; Steinvurzel, Paul; Rose, Todd S.; Lotshaw, William T.; Beck, Steven M.; Clemmons, James H.

    2016-03-01

    We demonstrate high power, deep ultraviolet (DUV) conversion to 266 nm through frequency quadrupling of a nanosecond pulse width 1064 nm fiber master oscillator power amplifier (MOPA). The MOPA system uses an Yb-doped double-clad polarization-maintaining large mode area tapered fiber as the final gain stage to generate 0.5-mJ, 10 W, 1.7- ns single mode pulses at a repetition rate of 20 kHz with measured spectral bandwidth of 10.6 GHz (40 pm), and beam qualities of Mx 2=1.07 and My 2=1.03, respectively. Using LBO and BBO crystals for the second-harmonic generation (SHG) and fourth-harmonic generation (FHG), we have achieved 375 μJ (7.5 W) and 92.5 μJ (1.85 W) at wavelengths of 532 nm and 266 nm, respectively. To the best of our knowledge these are the highest narrowband infrared, green and UV pulse energies obtained to date from a fully spliced fiber amplifier. We also demonstrate high efficiency SHG and FHG with walk-off compensated (WOC) crystal pairs and tightly focused pump beam. An SHG efficiency of 75%, FHG efficiency of 47%, and an overall efficiency of 35% from 1064 nm to 266 nm are obtained.

  19. A frequency-locked and frequency-doubled, hybrid Q-switched Yb:KYW laser at 515 nm with a widely adjustable repetition rate

    Science.gov (United States)

    Tjörnhammar, S.; Zukauskas, A.; Canalias, C.; Pasiskevicius, V.; Laurell, F.

    2015-09-01

    We demonstrate a compact wavelength-stabilized, frequency-doubled Yb-doped double-tungstate laser with widely tunable repetition rate, spanning from 35 Hz to 3 kHz obtained by hybrid Q-switching. The Q-switching unit consisted of a combination of a passive Cr:YAG crystal and an opto-mechanical active intensity modulator. The fundamental wavelength was locked at 1029 nm with a volume Bragg grating, and the pulse length and energy were 42 ns and 250 µJ, respectively. As the laser was stabilized with the VBG and the opto-mechanical modulator, the frequency instability was reduced six times from free running down to 0.29 %. Frequency doubling was done extra-cavity in PPKTP, and a repetition rate-independent conversion efficiency of 63 % was obtained. The controllable repetition rate together with stable temporal and spatial characteristics makes this laser a suitable candidate in many biology-related experiments, as a pump source for in vivo excitation of fluorophores, e.g., pumping of "living lasers" and matrix-assisted laser desorption/ionization mass spectroscopy.

  20. The role of Nb in intensity increase of Er ion upconversion luminescence in zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Smits, K., E-mail: smits@cfi.lu.lv; Sarakovskis, A.; Grigorjeva, L.; Millers, D. [Institute of Solid State Physics, University of Latvia, 8 Kengaraga Str., Riga LV1063 (Latvia); Grabis, J. [Institute of Inorganic Chemistry, Riga Technical University, Salaspils-1 LV2169 (Latvia)

    2014-06-07

    It is found that Nb co-doping increases the luminescence and upconversion luminescence intensity in rare earth doped zirconia. Er and Yb-doped nanocrystalline samples with or without Nb co-doping were prepared by sol-gel method and thermally annealed to check for the impact of phase transition on luminescence properties. Phase composition and grain sizes were examined by X-ray diffraction; the morphology was checked by scanning- and high-resolution transmission electron microscopes. Both steady-state and time-resolved luminescence were studied. Comparison of samples with different oxygen vacancy concentrations and different Nb concentrations confirmed the known assumption that oxygen vacancies are the main agents for tetragonal or cubic phase stabilization. The oxygen vacancies quench the upconversion luminescence; however, they also prevent agglomeration of rare-earth ions and/or displacement of rare-earth ions to grain surfaces. It is found that co-doping with Nb ions significantly (>20 times) increases upconversion luminescence intensity. Hence, ZrO{sub 2}:Er:Yb:Nb nanocrystals may show promise for upconversion applications.

  1. Power scaling analysis of fiber lasers and amplifiers based on non-silica materials

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, J W; Messerly, M J; Heebner, J E; Pax, P H; Sridharan, A K; Bullington, A L; Beach, R J; Siders, C W; Barty, C P; Dubinskii, M

    2010-03-30

    A developed formalism for analyzing the power scaling of diffraction limited fiber lasers and amplifiers is applied to a wider range of materials. Limits considered include thermal rupture, thermal lensing, melting of the core, stimulated Raman scattering, stimulated Brillouin scattering, optical damage, bend induced limits on core diameter and limits to coupling of pump diode light into the fiber. For conventional fiber lasers based upon silica, the single aperture, diffraction limited power limit was found to be 36.6kW. This is a hard upper limit that results from an interaction of the stimulated Raman scattering with thermal lensing. This result is dependent only upon physical constants of the material and is independent of the core diameter or fiber length. Other materials will have different results both in terms of ultimate power out and which of the many limits is the determining factor in the results. Materials considered include silica doped with Tm and Er, YAG and YAG based ceramics and Yb doped phosphate glass. Pros and cons of the various materials and their current state of development will be assessed. In particular the impact of excess background loss on laser efficiency is discussed.

  2. Glass-on-Glass Fabrication of Bottle-Shaped Tunable Micro-Lasers and Their Applications

    CERN Document Server

    Ward, Jonathan M; Chormaic, Sile Nic

    2016-01-01

    We describe a novel method for making microbottle-shaped lasers by using a CO$_2$ laser to melt Er:Yb glass onto silica microcapillaries or fibres. This is realised by the fact that the two glasses have different melting points. The CO$_2$ laser power is controlled to flow the doped glass around the silica cylinder. In the case of a capillary, the resulting geometry is a hollow, microbottle-shaped resonator. This is a simple method for fabricating a number of glass WGM lasers with a wide range of sizes on a single, micron-scale structure. The Er:Yb doped glass outer layer is pumped at 980 nm via a tapered optical fibre and whispering gallery mode (WGM) lasing is recorded around 1535 nm. This structure facilitates a new way to thermo-optically tune the microlaser modes by passing gas through the capillary. The cooling effect of the gas flow shifts the WGMs towards shorter wavelengths, thus thermal tuning of the lasing modes over 70 GHz is achieved. Results are fitted using the theory of hot wire anemometry, al...

  3. Multi-mJ, kHz picosecond deep UV source based on a frequency-quadrupled cryogenic Yb:YAG laser

    Science.gov (United States)

    Hong, Kyung-Han; Chang, Chun-Lin; Krogen, Peter; Liang, Houkun; Stein, Gregory J.; Moses, Jeffrey; Lai, Chien-Jen; Kärtner, Franz X.

    2015-05-01

    We report on the development of a 2.74-mJ, ~4.2 ps, ~258 nm deep-ultraviolet (DUV) source at 1 kHz based on frequency quadrupling of ~32 mJ, 8.4 ps, ~1030 nm near-infrared (NIR) laser pulses with an excellent beam profile, generated from a diode-pumped, ultrafast hybrid Yb-doped chirped-pulse amplification laser system. We have used a two-stage second harmonic generation scheme at LBO (NIR-to-green) and BBO crystals (green-to-DUV), respectively, to achieve the fourth-harmonic generation (FHG). The NIR-to-DUV conversion efficiency of ~10% in the FHG is obtained. The peak power of the produced DUV laser pulses is as high as 0.56 GW. The beam profiles at near-field and far-field are found to be excellent and the M2 value is measured as ~2.6. We also present the systematic parameter study on the optimization of DUV generation. To our best knowledge, this is the most energetic DUV generation from a diodepumped solid-state laser at kHz repetition rates.

  4. Bidirectional pumped high power Raman fiber laser.

    Science.gov (United States)

    Xiao, Q; Yan, P; Li, D; Sun, J; Wang, X; Huang, Y; Gong, M

    2016-03-21

    This paper presents a 3.89 kW 1123 nm Raman all-fiber laser with an overall optical-to-optical efficiency of 70.9%. The system consists of a single-wavelength (1070nm) seed and one-stage bidirectional 976 nm non-wavelength-stabilized laser diodes (LDs) pumped Yb-doped fiber amplifier. The unique part of this system is the application of non-wavelength-stabilized LDs in high power bidirectional pumping configuration fiber amplifier via refractive index valley fiber combiners. This approach not only increases the pump power, but also shortens the length of fiber by avoiding the usage of multi-stage amplifier. Through both theoretical research and experiment, the bidirectional pumping configuration presented in this paper proves to be able to convert 976 nm pump laser to 1070 nm laser via Yb3+ transfer, which is then converted into 1123 nm Raman laser via the first-order Raman effect without the appearance of any higher-order Raman laser. PMID:27136862

  5. Robust upward dispersion of the neutron spin resonance in the heavy fermion superconductor Ce1-xYbxCoIn5

    Science.gov (United States)

    Song, Yu; van Dyke, John; Lum, I. K.; White, B. D.; Jang, Sooyoung; Yazici, Duygu; Shu, L.; Schneidewind, A.; Čermák, Petr; Qiu, Y.; Maple, M. B.; Morr, Dirk K.; Dai, Pengcheng

    2016-09-01

    The neutron spin resonance is a collective magnetic excitation that appears in the unconventional copper oxide, iron pnictide and heavy fermion superconductors. Although the resonance is commonly associated with a spin-exciton due to the d(s+/-)-wave symmetry of the superconducting order parameter, it has also been proposed to be a magnon-like excitation appearing in the superconducting state. Here we use inelastic neutron scattering to demonstrate that the resonance in the heavy fermion superconductor Ce1-xYbxCoIn5 with x=0, 0.05 and 0.3 has a ring-like upward dispersion that is robust against Yb-doping. By comparing our experimental data with a random phase approximation calculation using the electronic structure and the momentum dependence of the -wave superconducting gap determined from scanning tunnelling microscopy (STM) for CeCoIn5, we conclude that the robust upward-dispersing resonance mode in Ce1-xYbxCoIn5 is inconsistent with the downward dispersion predicted within the spin-exciton scenario.

  6. Water-window soft x-ray high-harmonic generation up to the nitrogen K-edge driven by a kHz, 2.1 μm OPCPA source

    Science.gov (United States)

    Stein, Gregory J.; Keathley, Phillip D.; Krogen, Peter; Liang, Houkun; Siqueira, Jonathas P.; Chang, Chun-Lin; Lai, Chien-Jen; Hong, Kyung-Han; Laurent, Guillaume M.; Kärtner, Franz X.

    2016-08-01

    We report the generation of coherent water-window soft x-ray harmonics in a neon-filled semi-infinite gas cell driven by a femtosecond multi-mJ mid-infrared optical parametric chirped-pulse amplification (OPCPA) system at a 1 kHz repetition rate. The cutoff energy was extended to ∼450 eV with a 2.1 μm driver wavelength and a photon flux of ∼ 1.5× {10}6 photons/s/1% bandwidth was obtained at 350 eV. A comparable photon flux of ∼ 1.0× {10}6 photons/s/1% bandwidth was observed at the nitrogen K-edge of 410 eV. This is the first demonstration of water-window harmonic generation up to the nitrogen K-edge from a kHz OPCPA system. Finally, this system is suitable for time-resolved soft x-ray near-edge absorption spectroscopy. Further scaling of the driving pulse's energy and repetition rate is feasible due to the availability of high-power picosecond Yb-doped pump laser technologies, thereby enabling ultrafast, tabletop water-window x-ray imaging.

  7. Evaluation of inclusion level of wheat distillers dried grains with solubles with and without protease or β-mannanase on performance and water intake of turkey hens.

    Science.gov (United States)

    Opoku, E Y; Classen, H L; Scott, T A

    2015-07-01

    It is becoming a common practice to use higher levels of wheat distillers dried grains with solubles (wDDGS) in poultry diets. The objective of this study was to determine the effects of level of inclusion of wDDGS with or without enzyme (E-, i.e., wDDGSE-) supplementation on performance and water consumption of turkey hens (0 to 72 d). Two diets (0 or 30% wDDGS) were formulated to meet the nutrient requirements of Hybrid Converter turkeys. Diets (0 or 30% wDDGS; starter, grower, and finisher) were then blended to obtain a different level of inclusion (15%) of wDDGS. The 30% wDDGS diet was divided into 3 fractions and 2 fractions supplemented with either protease (P+, i.e., wDDGSP+; 0.126 g/kg) or β-mannanase (M+, i.e., wDDGSM+; 0.05 g/kg). All 5 diets were fed ad libitum as mash. The 700 0-d turkey hens were randomly allocated into groups of 35 birds per replicate with 4 replicate floor pens per treatment, in a completely randomized design. Water consumption per pen was recorded beginning at 7 d. There was no effect of dietary treatment on feed intake. BW of turkey hens (52 d; grower) was significantly higher for 30% wDDGSP+ as compared to 0% wDDGSE- or 15% wDDGSE- diets; but was not different from 30% wDDGSE- or 30% wDDGSM+ diets. FCR (P < 0.01; 28 to 52 d), and total FCR (P < 0.05; 0 to 72 d) was significantly improved for birds fed 15 or 30% wDDGS regardless of enzyme treatment compared to 0% wDDGSE-. Water intake (WI, in mL per bird per day) tended to be higher (P = 0.08) between 7 and 28 d for 30% wDDGSP+ diets compared to other treatments. Similarly, WI of birds fed 30% wDDGSP+ was higher (P < 0.05; 28 to 52 and 52 to 72 d) and total WI (P = 0.07; 7 to 72 d) tended to be higher than other treatments. This study is the first to report the impact of wDDGS on WI. As high as 30% wDDGS can be substituted in turkey hen diets. No effect of P+ or M+ at the inclusion level tested was found on performance. PMID:25971948

  8. A novel fiber laser development for photoacoustic microscopy

    Science.gov (United States)

    Yavas, Seydi; Aytac-Kipergil, Esra; Arabul, Mustafa U.; Erkol, Hakan; Akcaalan, Onder; Eldeniz, Y. Burak; Ilday, F. Omer; Unlu, Mehmet B.

    2013-03-01

    Photoacoustic microscopy, as an imaging modality, has shown promising results in imaging angiogenesis and cutaneous malignancies like melanoma, revealing systemic diseases including diabetes, hypertension, tracing drug efficiency and assessment of therapy, monitoring healing processes such as wound cicatrization, brain imaging and mapping. Clinically, photoacoustic microscopy is emerging as a capable diagnostic tool. Parameters of lasers used in photoacoustic microscopy, particularly, pulse duration, energy, pulse repetition frequency, and pulse-to-pulse stability affect signal amplitude and quality, data acquisition speed and indirectly, spatial resolution. Lasers used in photoacoustic microscopy are typically Q-switched lasers, low-power laser diodes, and recently, fiber lasers. Significantly, the key parameters cannot be adjusted independently of each other, whereas microvasculature and cellular imaging, e.g., have different requirements. Here, we report an integrated fiber laser system producing nanosecond pulses, covering the spectrum from 600 nm to 1100 nm, developed specifically for photoacoustic excitation. The system comprises of Yb-doped fiber oscillator and amplifier, an acousto-optic modulator and a photonic-crystal fiber to generate supercontinuum. Complete control over the pulse train, including generation of non-uniform pulse trains, is achieved via the AOM through custom-developed field-programmable gate-array electronics. The system is unique in that all the important parameters are adjustable: pulse duration in the range of 1-3 ns, pulse energy up to 10 μJ, repetition rate from 50 kHz to 3 MHz. Different photocoustic imaging probes can be excited with the ultrabroad spectrum. The entire system is fiber-integrated; guided-beam-propagation rendersit misalignment free and largely immune to mechanical perturbations. The laser is robust, low-cost and built using readily available components.

  9. Reduction of Photoluminescence Quenching by Deuteration of Ytterbium-Doped Amorphous Carbon-Based Photonic Materials

    Directory of Open Access Journals (Sweden)

    Hui-Lin Hsu

    2014-08-01

    Full Text Available In situ Yb-doped amorphous carbon thin films were grown on Si substrates at low temperatures (<200 °C by a simple one-step RF-PEMOCVD system as a potential photonic material for direct integration with Si CMOS back end-of-line processing. Room temperature photoluminescence around 1 µm was observed via direct incorporation of optically active Yb3+ ions from the selected Yb(fod3 metal-organic compound. The partially fluorinated Yb(fod3 compound assists the suppression of photoluminescence quenching by substitution of C–H with C–F bonds. A four-fold enhancement of Yb photoluminescence was demonstrated via deuteration of the a-C host. The substrate temperature greatly influences the relative deposition rate of the plasma dissociated metal-organic species, and hence the concentration of the various elements. Yb and F incorporation are promoted at lower substrate temperatures, and suppressed at higher substrate temperatures. O concentration is slightly elevated at higher substrate temperatures. Photoluminescence was limited by the concentration of Yb within the film, the concentration of Yb ions in the +3 state, and the relative amount of quenching due to the various de-excitation pathways associated with the vibrational modes of the host a-C network. The observed wide full-width-at-half-maximum photoluminescence signal is a result of the variety of local bonding environments due to the a-C matrix, and the bonding of the Yb3+ ions to O and/or F ions as observed in the X-ray photoelectron spectroscopy analyses.

  10. 11-W CW 100-μm fiber-coupled 971-nm Al-free active region pump source

    Science.gov (United States)

    Larat, Christian; Auzanneau, Sophie-Charlotte; Calligaro, Michel; Parillaud, Olivier; Krakowski, Michel; Boulant, Benoit; Laugustin, Arnaud; Fillardet, Thierry

    2004-05-01

    Laser diodes at 980 nm have important applications in medicine (surgery, dentistry) and Telecoms for WDM, high bit rate networks (Er or Er/Yb doped fibre amplifiers). These applications need a high coupling efficiency of the source into a fibre. High brightness mini-bars with an emissive length of 2.7 mm have been recently developed. These devices consist of an array of aluminium free active region index guided tapered laser diodes with standard AR/HR coatings. We have improved the performances as a result of a new epitaxial layer and a new mini-bar design. We measure an optical output power of 25W at 40A under CW operation at 15°C. At 25°C and 33A, we obtain 20W CW and the far field along the slow axis has a Gaussian shape, with a low FWHM value of 3.5°. Along the fast axis, the far-field also has a Gaussian shape and a FWHM of 31,5°. To couple this tapered diode laser mini-bar into a 100μm diameter fibre (0.26 numerical aperture), we use a patented collective beam shaping technique for optical coupling. We obtain a coupled power of 11.2W under CW operation at 971 nm, 21°C with an emitted power from the mini-bar of 21.7W, resulting in a coupling efficiency of 52%. The conductively cooled mini-bar, all the optics and the optical fibre connector are assembled into a 82x62x23mm package. To our knowledge this is the highest reported power coupled into 100μm optical fibre from a single laser diode chip using a collective coupling scheme without any array of micro-optics.

  11. Intensity noise reduction of a high-power nonlinear femtosecond fiber amplifier based on spectral-breathing self-similar parabolic pulse evolution

    Science.gov (United States)

    Wang, Sijia; Liu, Bowen; Song, Youjian; Hu, Minglie

    2016-04-01

    We report on a simple passive scheme to reduce the intensity noise of high-power nonlinear fiber amplifiers by use of the spectral-breathing parabolic evolution of the pulse amplification with an optimized negative initial chirp. In this way, the influences of amplified spontaneous emission (ASE) on the amplifier intensity noise can be efficiently suppressed, owing to the lower overall pulse chirp, shorter spectral broadening distance, as well as the asymptotic attractive nature of self-similar pulse amplification. Systematic characterizations of the relative intensity noise (RIN) of a free-running nonlinear Yb-doped fiber amplifier are performed over a series of initial pulse parameters. Experiments show that the measured amplifier RIN increases respect to the decreased input pulse energy, due to the increased amount of ASE noise. For pulse amplification with a proper negative initial chirp, the increase of RIN is found to be smaller than with a positive initial chirp, confirming the ASE noise tolerance of the proposed spectral-breathing parabolic amplification scheme. At the maximum output average power of 27W (25-dB amplification gain), the incorporation of an optimum negative initial chirp (-0.84 chirp parameter) leads to a considerable amplifier root-mean-square (rms) RIN reduction of ~20.5% (integrated from 10 Hz to 10 MHz Fourier frequency). The minimum amplifier rms RIN of 0.025% (integrated from 1 kHz to 5 MHz Fourier frequency) is obtained along with the transform-limited compressed pulse duration of 55fs. To our knowledge, the demonstrated intensity noise performance is the lowest RIN level measured from highpower free-running femtosecond fiber amplifiers.

  12. Lattice mismatch and crystal growth of monoclinic KY{sub 1-x}Yb{sub x}(WO{sub 4}){sub 2}/KY (WO{sub 4}){sub 2} layers by liquid phase epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Silvestre, O; Aznar, A; Sole, R; Pujol, M C; Diaz, F; Aguilo, M [Fisica i Cristallografia de Materials (FiCMA), Universitat Rovira i Virgili (URV), Campus Sescelades c/Marcel-Ii Domingo, s/n, E-43007-Tarragona (Spain)], E-mail: magdalena.aguilo@urv.cat

    2008-06-04

    Monoclinic layers of KY{sub 1-x}Yb{sub x}(WO{sub 4}){sub 2} with a thickness of up to 330 {mu}m were grown on KY (WO{sub 4}){sub 2} substrates by liquid phase epitaxy (LPE) using K{sub 2}W{sub 2}O{sub 7} solvent. The layers grown from solutions of up to 7.5 at.% substitution of Y by Yb generally had flat surfaces on {l_brace}010{r_brace} and {l_brace}110{r_brace} crystal faces with no macroscopic defects at the layer/substrate interface. Already at 10 at.% of Yb substituting Y, some defects at the interface tend to appear and increase for higher concentrations. The layers grown on {l_brace}310{r_brace} and {l_brace}111{r_brace} faces show more growth instabilities even at low Yb concentrations. The thermal evolutions of the lattice mismatches between the epilayer and the substrate for {l_brace}110{r_brace}, {l_brace}110{r_brace}, {l_brace}310{r_brace} and {l_brace}111{r_brace} faces were calculated to range from 0.55% at 1273 K to -0.31% at 298 K. The optical spectroscopic studies carried out with these samples agree well with Yb-doped KYW bulk crystals, the measured absorption and calculated (by the reciprocity method) emission cross-sections at 981 nm with E II N{sub m} being {sigma}{sub abs} = 12.5 x 10{sup -20} cm{sup 2} and {sigma}{sub em} = 15.8 x 10{sup -20} cm{sup 2}, respectively.

  13. Fiber laser pumped burst-mode operated picosecond mid-infrared laser

    Science.gov (United States)

    Wei, Kai-Hua; Jiang, Pei-Pei; Wu, Bo; Chen, Tao; Shen, Yong-Hang

    2015-02-01

    We demonstrate a compact periodically poled MgO-doped lithium niobate (MgO:PPLN)-based optical parametric oscillator (OPO) quasi-synchronously pumped by a fiber laser system with burst-mode operation. The pump source is a peak-power-selectable pulse-multiplied picosecond Yb fiber laser. The chirped pulses from a figure of eight-cavity mode-locked fiber laser seed are narrowed to a duration of less than 50 ps using an FBG reflector and a circulator. The narrowed pulses are directed to pass through a pulse multiplier and to form pulse bunches, each of which is composed of 13 sub-pulses. The obtained pulse bunches are amplified by two-stage fiber pre-amplifiers: one-stage is core-pumped and the other is cladding-pumped. A fiberized acousto-optic modulator is inserted to control the pulse repetition rate (PRR) of the pulse bunches before they are power-amplified in the final amplifier stage with a large mode area (LMA) PM Yb-doped fiber. The maximum average powers from the final amplifier are 85 W, 60 W, and 45 W, respectively, corresponding to the PRR of 2.72 MHz, 1.36 MHz, and 0.68 MHz. The amplified pulses are directed to pump an MgO:PPLN-based optical parametric oscillator (OPO). A maximum peak power at 3.45 μm is obtained approximately to be 8.4 kW. Detailed performance characteristics are presented. Project supported by the National Natural Science Foundation of China (Grant No. 61078015) and the National Basic Research Program of China (Grant No. 2011CB311803).

  14. Wavelength locking of single emitters and multi-emitter modules: simulation and experiments

    Science.gov (United States)

    Yanson, Dan; Rappaport, Noam; Peleg, Ophir; Berk, Yuri; Dahan, Nir; Klumel, Genady; Baskin, Ilya; Levy, Moshe

    2016-03-01

    Wavelength-stabilized high-brightness single emitters are commonly used in fiber-coupled laser diode modules for pumping Yb-doped lasers at 976 nm, and Nd-doped ones at 808 nm. We investigate the spectral behavior of single emitters under wavelength-selective feedback from a volume Bragg (or hologram) grating (VBG) in a multi-emitter module. By integrating a full VBG model as a multi-layer thin film structure with commercial raytracing software, we simulated wavelength locking conditions as a function of beam divergence and angular alignment tolerances. Good correlation between the simulated VBG feedback strength and experimentally measured locking ranges, in both VBG misalignment angle and laser temperature, is demonstrated. The challenges of assembling multi-emitter modules based on beam-stacked optical architectures are specifically addressed, where the wavelength locking conditions must be achieved simultaneously with high fiber coupling efficiency for each emitter in the module. It is shown that angular misorientation between fast and slow-axis collimating optics can have a dramatic effect on the spectral and power performance of the module. We report the development of our NEON-S wavelength-stabilized fiber laser pump module, which uses a VBG to provide wavelength-selective optical feedback in the collimated portion of the beam. Powered by our purpose-developed high-brightness single emitters, the module delivers 47 W output at 11 A from an 0.15 NA fiber and a 0.3 nm linewidth at 976 nm. Preliminary wavelength-locking results at 808 nm are also presented.

  15. Sub-300-femtosecond operation from a MIXSEL.

    Science.gov (United States)

    Mangold, Mario; Golling, Matthias; Gini, Emilio; Tilma, Bauke W; Keller, Ursula

    2015-08-24

    Peak power scaling of semiconductor disk lasers is important for many applications, but their complex pulse formation mechanism requires a rigorous pulse characterization to confirm stable fundamental modelocking. Here we fully confirm sub-300-fs operation of Modelocked Integrated eXternal-cavity Surface Emitting Lasers (MIXSELs) with record high peak power at gigahertz pulse repetition rates. A strain-compensated InGaAs quantum well gain section enables an emission wavelength in the range of Yb-doped amplifiers at ≈1030 nm. We demonstrate the shortest pulses from a MIXSEL with a duration of 253 fs with 240 W of peak power, the highest peak power generated from any MIXSEL to date. This peak power performance is comparable to conventional SESAM-modelocked VECSELs for the first time. At a 10-GHz pulse repetition rate we still obtained 279-fs pulses with 310 mW of average output power, which is currently the highest output power of any femtosecond MIXSEL. Continuous tuning of the pulse repetition rate has been demonstrated with sub-400-fs pulse durations and >225 mW of average output power between 2.9 and 3.4 GHz. The strain-compensated MIXSEL chip allowed for more detailed parameter studies with regards to different heat sink temperatures, pump power, and epitaxial homogeneity of the MIXSEL chip for the first time. We discuss in detail, how the critical temperature balance between quantum well gain and quantum well absorber, the partially saturated absorber and a limited epitaxial growth quality influence the overall device efficiency. PMID:26368179

  16. Cost of electricity difference for direct and indirect drive targets for inertial fusion energy using a diode pumped solid state laser driver

    International Nuclear Information System (INIS)

    A detailed systems analysis code has been used to compare the projected cost of electricity (COE) for inertial fusion energy for direct drive (DD) and indirect drive (ID) target scenarios, based on a diode pumped solid state laser driver with Yb:S-FAP (Yb doped Sr5(PO4)3F) gain media. Previously published target gain curves which resulted in a target gain at the optimal DD operating point that is 30% higher than that for the ID scenario have been used. This gain advantage for DD is offset by a requirement for improved beam smoothing, which was obtained via smoothing by spectral dispersion (SSD) with a 1 THz bandwidth at 349 nm. Such a large SSD bandwidth has a number of effects on laser performance, including greater risk of optics damage from non-linear effects, lowered harmonic conversion efficiency, altered extraction parameters and higher front-end costs. The non-linear effects, which contribute to optical component damage by amplification of intensity non-uniformities, were parameterized through a constraint on the maximum allowable B integral (i.e. the total average phase retardation due to the non-linear indices of all materials traversed by the beam). If we constrain B to be no larger than 1.8 rad, which is the presently accepted safe value based on observations in single shot glass laser facilities, the COEs for DD and ID are predicted to be the same within the uncertainties. If technology permits the B limit to be raised, the optimized COE for DD is predicted to decrease relative to that for ID. (author)

  17. Effect of rare earth substitution in cobalt ferrite bulk materials

    Energy Technology Data Exchange (ETDEWEB)

    Bulai, G., E-mail: georgiana.bulai@uaic.ro [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bd. Carol I, nr. 11, 700506 Iasi (Romania); Diamandescu, L. [National Institute of Material Physics, P.O. Box MG-7, 07125 Bucharest (Romania); Dumitru, I.; Gurlui, S. [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bd. Carol I, nr. 11, 700506 Iasi (Romania); Feder, M. [National Institute of Material Physics, P.O. Box MG-7, 07125 Bucharest (Romania); Caltun, O.F. [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bd. Carol I, nr. 11, 700506 Iasi (Romania)

    2015-09-15

    The study was focused on the influence of small amounts of rare earth (RE=La, Ce, Sm, Gd, Dy, Ho, Er, Yb) addition on the microstructure, phase content and magnetic properties of cobalt ferrite bulk materials. The X-Ray diffraction measurements confirmed the formation of the spinel structure but also the presence of secondary phases of RE oxides or orthoferrite in small percentages (up to 3%). Density measurements obtained by Archimedes method revealed a ~1 g cm{sup −3} decrease for the RE doped cobalt ferrite samples compared with stoichiometric one. Both the Mössbauer and Fourier Transform Infrared Spectrocopy analysis results confirmed the formation of the spinel phase. The saturation magnetization and coercive field values of the doped samples obtained by Vibrating Sample Magnetometry were close to those of the pure cobalt ferrite. For magnetostrictive property studies the samples were analyzed using the strain gauge method. Higher maximum magnetostriction coefficients were found for the Ho, Ce, Sm and Yb doped cobalt ferrite bulk materials as related to the stoichiometric CoFe{sub 2}O{sub 4} sample. Moreover, improved strain derivative was observed for these samples but at higher magnetic fields due to the low increase of the coercive field values for doped samples. - Highlights: • Substitution by a large number of rare earth elements was investigated. • First reported results on magnetostriction measurements of RE doped cobalt ferrite. • The doped samples presented an increased porosity and a decreased grain size. • Increased magnetostrctive response was observed for several doped samples.

  18. Preparation and electrochemical properties of SrCe0.4Zr0.4Yb0.2O2.9 electrolyte

    Indian Academy of Sciences (India)

    Juan Li; Ruisong Guo; Hong Jiang

    2012-11-01

    The perovskite Yb-doped strontium cerate–zirconate material, SrCe0.4Zr0.4Yb0.2O2.9, was prepared by solid-state reaction and the structure was characterized by X-ray diffraction. The calcination process of the powder was investigated by thermogravimetric/differential thermal analysis (TG–DTA). The high temperature conductivities were measured by d.c. four-probe technique in the temperature range from 500 to 950°C in wet hydrogen and effect of temperature on conductivity was investigated. The conductivity increased with the elevation of temperature from 500 to 950°C. The highest conductivity of 4.4 × 10-2 S.cm-1 was observed for SrCe0.4Zr0.4Yb0.2O2.9 at 950°C. The current–voltage (–) and current–power (–) characteristics of the single cell (H2, Pt/SrCe0.4Zr0.4Yb0.2O2.9/Pt, O2) at temperature range from 600 to 850°C were tested. With the temperature increasing from 600 to 850°C, the open circuit voltage (OCV) decreased from 1.164 to 1.073 V and the ionic transfer number decreased from 0.996 to 0.946. At 850°C, the maximum power density of 25.2 mW.cm-2 was observed.

  19. Layered Yb:YAG ceramics produced by two different methods: processing, characterization and comparison

    Science.gov (United States)

    Hostaša, Jan; Esposito, Laura; Biasini, Valentina; Piancastelli, Andreana; Vannini, Matteo; Toci, Guido

    2016-03-01

    The use of Yb:YAG ceramic gain media in solid state lasers has been of growing interest for high repetition rate and high power lasers. Probably the most important advantage of ceramic production technology in comparison with that of single crystals is the flexibility of shaping methods that allow the production of near-net-shape components with a welldefined internal structure. In the case of Yb:YAG with dopant distribution designed accordingly to the pumping and cooling geometry the efficiency of the laser device can be enhanced by mitigating thermal lensing effects. The presented work reports on Yb:YAG transparent ceramics composed of layers with different Yb doping produced by two different shaping methods: dry pressing of spray-dried powders and tape casting, all sintered under high vacuum. The selected geometry of materials was based on numerical simulations. Microstructure of the produced materials was characterized by SEM and EDX with a particular attention to the dopant content across the layers. The optical quality of produced ceramics was characterized and discussed in connection with the microstructure and laser emission results. Output power of nearly 7 W and slope efficiency 58.1 % were obtained in QCW regime from bilayered 0-10 %Yb:YAG. In the case of multilayered materials higher scattering losses were observed. The comparison between the two processing methods highlighted that the tape-cast materials provided higher optical uniformity and the diffusion zone between the single layers with different dopant content was about 150 nm compared to about 250 nm in samples produced by pressing of powders.

  20. Optical properties of Yb ions in GaN epilayer

    Science.gov (United States)

    Jadwisienczak, W. M.; Lozykowski, H. J.

    2003-07-01

    In recent years, an important effort in semiconductor materials research has been devoted to III-nitrides semiconductors doped with rare earth ions due to the high potential of these materials in light-emitting device applications. Ytterbium (Yb 3+) is one of a few lanthanide ions which have not been investigated as an optically active center in these materials yet. In this paper we report the observation of luminescence from GaN films grown on sapphire (0 0 0 1) substrate by metal organic chemical vapor deposition and doped by implantation with Yb 3+ ions. The high resolution photo- and cathodoluminescence spectra of GaN:Yb 3+ were studied at different excitation conditions in temperatures ranging from 8 to 330 K and revealed weak thermal quenching. The luminescence emission lines are assigned to transitions between the spin-orbit levels 2F 5/2 → 2F 7/2 of Yb 3+ (4f 13). The analysis of the Yb luminescence spectra allowed us to suggest the energy level diagram of the crystal-field-split 4f 13 levels for the Yb ion center. The most probable lattice location of Yb in GaN is the substitutional Ga site. Furthermore, the luminescence kinetics of internal transitions of Yb 3+ incorporated in GaN was investigated by means of decay and time-resolved luminescence measurements. It was found that the ytterbium decay is non-exponential with dominant exponential term of ˜100 μs with little dependence on the ambient temperature. The results indicate that Yb-doped GaN epilayer may be suitable as a material for near infrared optoelectronic devices.

  1. Genetic algorithm based optimization of pulse profile for MOPA based high power fiber lasers

    Science.gov (United States)

    Zhang, Jiawei; Tang, Ming; Shi, Jun; Fu, Songnian; Li, Lihua; Liu, Ying; Cheng, Xueping; Liu, Jian; Shum, Ping

    2015-03-01

    Although the Master Oscillator Power-Amplifier (MOPA) based fiber laser has received much attention for laser marking process due to its large tunabilty of pulse duration (from 10ns to 1ms), repetition rate (100Hz to 500kHz), high peak power and extraordinary heat dissipating capability, the output pulse deformation due to the saturation effect of fiber amplifier is detrimental for many applications. We proposed and demonstrated that, by utilizing Genetic algorithm (GA) based optimization technique, the input pulse profile from the master oscillator (current-driven laser diode) could be conveniently optimized to achieve targeted output pulse shape according to real parameters' constraints. In this work, an Yb-doped high power fiber amplifier is considered and a 200ns square shaped pulse profile is the optimization target. Since the input pulse with longer leading edge and shorter trailing edge can compensate the saturation effect, linear, quadratic and cubic polynomial functions are used to describe the input pulse with limited number of unknowns(cost and hardware limitations, the cubic input pulse with 4 coefficients is found to be the best as the output amplified pulse can achieve excellent flatness within the square shape. Considering the bandwidth constraint of practical electronics, we examined high-frequency component cut-off effect of input pulses and found that the optimized cubic input pulses with 300MHz bandwidth is still quite acceptable to satisfy the requirement for the amplified output pulse and it is feasible to establish such a pulse generator in real applications.

  2. Compact fixed wavelength femtosecond oscillators as an add-on for tunable Ti:sapphire lasers extend the range of applications towards multimodal imaging and optogenetics

    Science.gov (United States)

    Hakulinen, T.; Klein, J.

    2016-03-01

    Two-photon (2P) microscopy based on tunable Ti:sapphire lasers has become a widespread tool for 3D imaging with sub-cellular resolution in living tissues. In recent years multi-photon microscopy with simpler fixed-wavelength femtosecond oscillators using Yb-doped tungstenates as gain material has raised increasing interest in life-sciences, because these lasers offer one order of magnitude more average power than Ti:sapphire lasers in the wavelength range around 1040 nm: Two-photon (2P) excitation of mainly red or yellow fluorescent dyes and proteins (e.g. YFP, mFruit series) simultaneously has been proven with a single IR laser wavelength. A new approach is to extend the usability of existing tunable Titanium sapphire lasers by adding a fixed IR wavelength with an Yb femtosecond oscillator. By that means a multitude of applications for multimodal imaging and optogenetics can be supported. Furthermore fs Yb-lasers are available with a repetition rate of typically 10 MHz and an average power of typically 5 W resulting in pulse energy of typically 500 nJ, which is comparably high for fs-oscillators. This makes them an ideal tool for two-photon spinning disk laser scanning microscopy and holographic patterning for simultaneous photoactivation of large cell populations. With this work we demonstrate that economical, small-footprint Yb fixed-wavelength lasers can present an interesting add-on to tunable lasers that are commonly used in multiphoton microscopy. The Yb fs-lasers hereby offer higher power for imaging of red fluorescent dyes and proteins, are ideally enhancing existing Ti:sapphire lasers with more power in the IR, and are supporting pulse energy and power hungry applications such as spinning disk microscopy and holographic patterning.

  3. Shear and Rapeseed Oil Addition Affect the Crystal Polymorphic Behavior of Milk Fat

    DEFF Research Database (Denmark)

    Kaufmann, Niels; Kirkensgaard, Jacob Judas Kain; Andersen, Ulf;

    2013-01-01

    The effect of shear on the crystallization kinetics of anhydrous milk fat (AMF) and blends with 20 and 30 % w/w added rapeseed oil (RO) was studied. Pulse 1H NMR was used to follow the a to b0 polymorphic transition. The NMR method was confirmed and supported by SAXS/WAXS experiments. Samples were...

  4. Measurement of Thermal Lens Focal Length and Its Effect on Laser Output Characteristics in LD End-pumped Nd∶YVO4 Lasers

    Institute of Scientific and Technical Information of China (English)

    WAN Chunming(万春明); WANG Hui(王慧)

    2002-01-01

    According to the resonator transform circle theory, the focal length of thermal lens of laser media in laser diode end-pumped solid-state lasers is analyzed and measured with a simple method. A 30W 808nm LD pumped YVO4 laser is developed and characterized.

  5. Tensile properties of cellulose fiber reinforced hydroxypropylcellulose films

    NARCIS (Netherlands)

    Borges, J.P.; Godinho, M.H.; Martins, A.F.; Stamatialis, D.F.; De Pinho, M.N.; Belgacem, M.N.

    2004-01-01

    The tensile properties of cross-linked and uncross-linked composite films (thickness 20-35 m) prepared from Hydroxypropylcellulose (HPC) with incorporation of microcrystalline cellulose fibers (Avicel) were studied. The concentration of fibers in the composites ranged from 0 to 30 w/w% and cross-lin

  6. Influence of water availability on the enzymatic hydrolysis of proteins

    NARCIS (Netherlands)

    Butré, C.I.; Wierenga, P.A.; Gruppen, H.

    2014-01-01

    The overall rate of enzymatic protein hydrolysis decreases with increasing protein concentration (0.1–30% (w/v)) at constant enzyme/substrate ratio. To understand the role of water, the amount of available water was expressed as the ratio between free and bound water and experimentally determined fr

  7. Light weight digital array SAR

    NARCIS (Netherlands)

    Otten, M.; Maas, N.; Bolt, R.; Anitori, L.

    2010-01-01

    A light weight SAR has been designed, suitable for short range tactical UAVs, consisting of a fully digital receive array, and a very compact active transmit antenna. The weight of the complete RF front is expected to be below 3 kg, with a power consumption below 30 W. This X-band system can provide

  8. 76 FR 47566 - Nationwide Categorical Waivers Under Section 1605 (Buy American) of the American Recovery and...

    Science.gov (United States)

    2011-08-05

    ... for: (1) 2-10 horsepower, self contained, sensorless, variable speed pumps; (2) bi-directional bicycle... electric drive submersible pump motors (motors only, not pumps themselves); and (8) flush-to-handrail LED... contained, sensorless, variable speed pumps; (2) bi-directional bicycle counters; (3) 28W, 30W, and 60W...

  9. CORN GLUTEN MEAL AS A THERMOPLASTIC RESIN: EFFECT OF PLASTICIZERS AND WATER CONTENT

    Science.gov (United States)

    Corn gluten meal (CGM) was studied to investigate the effect plasticizers and water have on its melt processing, and how this melting affects its mechanical properties. CGM containing varying amounts of water were mixed with 30%(w/w) plasticizers; (glycerol, triethylene glycol (TEG), dibutyl tartra...

  10. Effects of Ionic Strength on the Enzymatic Hydrolysis of Diluted and Concentrated Whey Protein Isolate

    NARCIS (Netherlands)

    Butré, C.I.; Wierenga, P.A.; Gruppen, H.

    2012-01-01

    To identify the parameters that affect enzymatic hydrolysis at high substrate concentrations, whey protein isolate (1–30% w/v) was hydrolyzed by Alcalase and Neutrase at constant enzyme-to-substrate ratio. No changes were observed in the solubility and the aggregation state of the proteins. With inc

  11. Insights into Hemoglobin Assembly through in Vivo Mutagenesis of α-Hemoglobin Stabilizing Protein*

    Science.gov (United States)

    Khandros, Eugene; Mollan, Todd L.; Yu, Xiang; Wang, Xiaomei; Yao, Yu; D'Souza, Janine; Gell, David A.; Olson, John S.; Weiss, Mitchell J.

    2012-01-01

    α-Hemoglobin stabilizing protein (AHSP) is believed to facilitate adult Hemoglobin A assembly and protect against toxic free α-globin subunits. Recombinant AHSP binds multiple forms of free α-globin to stabilize their structures and inhibit precipitation. However, AHSP also stimulates autooxidation of αO2 subunit and its rapid conversion to a partially unfolded bishistidyl hemichrome structure. To investigate these biochemical properties, we altered the evolutionarily conserved AHSP proline 30 in recombinantly expressed proteins and introduced identical mutations into the endogenous murine Ahsp gene. In vitro, the P30W AHSP variant bound oxygenated α chains with 30-fold increased affinity. Both P30W and P30A mutant proteins also caused decreased rates of αO2 autooxidation as compared with wild-type AHSP. Despite these abnormalities, mice harboring P30A or P30W Ahsp mutations exhibited no detectable defects in erythropoiesis at steady state or during induced stresses. Further biochemical studies revealed that the AHSP P30A and P30W substitutions had minimal effects on AHSP interactions with ferric α subunits. Together, our findings indicate that the ability of AHSP to stabilize nascent α chain folding intermediates prior to hemin reduction and incorporation into adult Hemoglobin A is physiologically more important than AHSP interactions with ferrous αO2 subunits. PMID:22287545

  12. Insights into hemoglobin assembly through in vivo mutagenesis of α-hemoglobin stabilizing protein.

    Science.gov (United States)

    Khandros, Eugene; Mollan, Todd L; Yu, Xiang; Wang, Xiaomei; Yao, Yu; D'Souza, Janine; Gell, David A; Olson, John S; Weiss, Mitchell J

    2012-03-30

    α-Hemoglobin stabilizing protein (AHSP) is believed to facilitate adult Hemoglobin A assembly and protect against toxic free α-globin subunits. Recombinant AHSP binds multiple forms of free α-globin to stabilize their structures and inhibit precipitation. However, AHSP also stimulates autooxidation of αO(2) subunit and its rapid conversion to a partially unfolded bishistidyl hemichrome structure. To investigate these biochemical properties, we altered the evolutionarily conserved AHSP proline 30 in recombinantly expressed proteins and introduced identical mutations into the endogenous murine Ahsp gene. In vitro, the P30W AHSP variant bound oxygenated α chains with 30-fold increased affinity. Both P30W and P30A mutant proteins also caused decreased rates of αO(2) autooxidation as compared with wild-type AHSP. Despite these abnormalities, mice harboring P30A or P30W Ahsp mutations exhibited no detectable defects in erythropoiesis at steady state or during induced stresses. Further biochemical studies revealed that the AHSP P30A and P30W substitutions had minimal effects on AHSP interactions with ferric α subunits. Together, our findings indicate that the ability of AHSP to stabilize nascent α chain folding intermediates prior to hemin reduction and incorporation into adult Hemoglobin A is physiologically more important than AHSP interactions with ferrous αO(2) subunits.

  13. Wound healing activity of ethanolic extract of Shorea robusta Gaertn. f. resin.

    Science.gov (United States)

    Wani, T A; Chandrashekara, H H; Kumar, D; Prasad, R; Gopal, A; Sardar, K K; Tandan, S K; Kumar, D

    2012-04-01

    The ethanolic extract of S. robusta resin (10 and 30 % w/w applied locally in excised and incised wounds) produced a dose-dependent acceleration in wound contraction and increased hydroxyproline content and tensile strength of wounds in rats. The results demonstrate wound healing activity of ethanolic extract of S. robusta resin.

  14. Monitoring lipase-catalyzed interesterification for bulky fats modification with FT-IR/NIR spectroscopy

    DEFF Research Database (Denmark)

    Chang, Tinghong; Lai, Xuxin; Zhang, Hong;

    2005-01-01

    This work demonstrates the application of FT-IR and FT-NIR spectroscopy to monitor the enzymatic interesterification process for bulky fat modification. The reaction was conducted between palm stearin and coconut oil (70/30, w/w) with the catalysis of Lipozyme TL IM at 70°C in a batch reactor...

  15. A power-efficient audio amplifier combining switching and linear techniques

    NARCIS (Netherlands)

    Zee, van der Ronan A.R.; Tuijl, van Ed (A.J.M.)

    1999-01-01

    Integrated class-D audio amplifiers are very power efficient but require an external LC reconstruction filter, which prevents further integration. Also due to this filter, large feedback factors are hard to realize, so that the load influences the distortion and transfer characteristics. The 30 W am

  16. Biological responses to current UV-B radiation in Arctic regions

    DEFF Research Database (Denmark)

    Albert, Kristian; N. Mikkelsen, Teis; Ro-Poulsen, Helge

    Depletion of the ozone layer and the consequent increase in solar ultraviolet-B radiation (UV-B) may impact living conditions for arctic plants significantly. In order to evaluate how the prevailing UV-B fluxes affect the heath ecosystem at Zackenberg (74°30'N, 20°30'W) and other high...

  17. Recrystallization of amylopectin in concentrated starch gels

    NARCIS (Netherlands)

    Keetels, CJAM; Oostergetel, GT; vanVliet, T

    1996-01-01

    The relation between the recrystallization of amylopectin and the increase in stiffness of starch gels during storage was studied by various techniques. From transmission electron microscopy it was concluded that the size of the crystalline domains in retrograded 30% w/w potato starch gels was about

  18. 77 FR 30891 - Special Local Regulations and Safety Zones; Recurring Events in Northern New England

    Science.gov (United States)

    2012-05-24

    ... 07'38'' N, 068 31'30'' W. 44 12'54'' N, 068 33'46'' W. Lake Champlain Dragon Boat Festival.... Event.... SEPTEMBER Pirates Festival Lobster Boat Races.... Event Type: Power Boat Race. Sponsor: Eastport Pirates... and spectators from the hazards associated with powerboat races, regattas, boat parades, rowing...

  19. 78 FR 35135 - Special Local Regulations and Safety Zones; Recurring Events in Northern New England

    Science.gov (United States)

    2013-06-12

    ...'' W. 44 07'38'' N, 068 31'30'' W. 44 12'54'' N, 068 33'46'' W. Lake Champlain Dragon Boat Festival..., 073 21'36'' W. Yarmouth Clam Festival Paddle Race..... Event Type: Rowing and Paddling Boat Race... Pirates Festival Lobster Boat Races.... Event Type: Power Boat Race. Sponsor: Eastport Pirates...

  20. 77 FR 2629 - Special Local Regulations; Recurring Marine Events in the Fifth Coast Guard District

    Science.gov (United States)

    2012-01-19

    ... 076 03'46'' W. 6 May--3rd Friday, Dragon Boat Races at Dragon Boat Festival, The waters of the Upper... on the east by a line drawn along longitude 076 36'30'' W. 14 June--3rd, 4th or Baltimore Dragon Boat Baltimore Dragon Boat The waters of the last Saturday or Challenge. Club. Patapsco River, Sunday....

  1. The effects of extrusion of wheat distillers dried grains with solubles with or without an enzyme cocktail on performance of turkey hen poults.

    Science.gov (United States)

    Opoku, E Y; Classen, H L; Scott, T A

    2015-02-01

    Two experiments were conducted to determine if extrusion (EX) or enzymes (E) could overcome the restrictions (e.g., high fiber) of feeding wheat distillers dried grain with solubles (wDDGS) and improve its nutritional value for feeding turkeys. Two starter diets with either 0 or 30% wDDGS were formulated to meet or exceed the nutrient requirements of the Hybrid Converter female turkeys. The 30% wDDGS diet was substituted with either non-extruded (EX-) or extruded (EX+) wDDGS to produce three basal diets [0% wDDGS (EX-) or 30% wDDGS (EX-/EX+)]. Diets were blended to obtain 15% wDDGS. In the respective treatments, only wDDGS was extruded (temperature; 118°C, retention; 15 sec, total moisture; 25% and pressure 33 bar). The respective experimental diets were supplemented with/without an enzyme cocktail (E; 0.5 g/kg). Test diets were fed from 7-21 d in a completely randomized design. In Experiment 1, a total of 210 turkey hen poults were fed diets containing 0, 15, or 30% wDDGS (EX-) with or without enzyme (E+/E-). Body weight (BW) and feed intake (FI) were significantly higher for 0% wDDGSE-. Nitrogen retention (NR) and apparent metabolizable energy (AME) for the 30% wDDGSE- was significantly higher than other treatments at 21 d. The results indicated significant main effects of E and an interaction between wDDGS level and E. In Experiment 2, 280 turkey hen poults were fed 8 diets [15/30% wDDGS (E+/E-), (EX-/EX+)]. The level of wDDGS had a significant effect on BW, FI and gain:feed; 15% inclusion was superior to 30%. There were significant 2- and 3-way interactions for AME and NR at 21 d due to differences in enzyme response with 15 or 30% wDDGS inclusion and/or extrusion of wDDGS. As high as 15% wDDGS can be incorporated in turkey hen diets. There were no beneficial effects of EX or E on poult performance. PMID:25595482

  2. Towards a greater understanding of hydrothermally grown garnets and sesquioxide crystals for laser applications

    Science.gov (United States)

    Moore, Cheryl Ann

    The hydrothermal method of crystal growth offers many benefits over traditional melt-based techniques such as lower temperature requirements relieving detrimental high temperature effects such as stress fracturing and a closed-environment, which limits impurities. The continued study of this type of growth including hydrothermal epitaxy is crucial in our world of constant miniaturization. Presented in this thesis is the hydrothermal growth of crystals of LuAG and Lu2O3 doped with a variety of dopants. Their room-temperature and cryogenic absorption spectra are also presented. Much like Nature uses heat, pressure, water and a nutrient-rich feedstock we have used this hydrothermal technique to produce synthetic crystals of grossular, Ca3Al2(SiO4)3, a naturally occurring garnet as well as other aluminosilicates related to grossular, including a new type of vesuvianite. Other garnets important to the laser industry have also been grown using the hydrothermal technique, such as yttrium aluminum garnet (YAG), lutetium aluminum garnet (LuAG) and the related sesquioxide Lu2O3, (lutetia). The growth and characteristics of Yb-doped lutetia and LuAG, Nd-doped lutetia, and Dy-doped lutetia and YAG are presented herein. These laser crystals have been analyzed by high-resolution absorption spectroscopy at room temperature as well as 250K, 200K, 150K and 80K and absorption coefficients are presented. A coprecipitation technique common in the ceramics field has been adapted for use creating precursors for hydrothermal crystal growth, including phase-pure polycrystalline anorthite and phase-pure gehlenite. Coprecipitation has also been utilized to gain greater control of dopants to create pre-doped feedstocks used for the growth of laser crystal. The versatility of the hydrothermal growth method is also highlighted in a novel epitaxial technique, core growth, which coats the internal surfaces of a seed crystal as well as external surfaces. This can result in multifunctional

  3. Bulk damage and absorption in fused silica due to high-power laser applications

    Science.gov (United States)

    Nürnberg, F.; Kühn, B.; Langner, A.; Altwein, M.; Schötz, G.; Takke, R.; Thomas, S.; Vydra, J.

    2015-11-01

    Laser fusion projects are heading for IR optics with high broadband transmission, high shock and temperature resistance, long laser durability, and best purity. For this application, fused silica is an excellent choice. The energy density threshold on IR laser optics is mainly influenced by the purity and homogeneity of the fused silica. The absorption behavior regarding the hydroxyl content was studied for various synthetic fused silica grades. The main absorption influenced by OH vibrational excitation leads to different IR attenuations for OH-rich and low-OH fused silica. Industrial laser systems aim for the maximum energy extraction possible. Heraeus Quarzglas developed an Yb-doped fused silica fiber to support this growing market. But the performance of laser welding and cutting systems is fundamentally limited by beam quality and stability of focus. Since absorption in the optical components of optical systems has a detrimental effect on the laser focus shift, the beam energy loss and the resulting heating has to be minimized both in the bulk materials and at the coated surfaces. In collaboration with a laser research institute, an optical finisher and end users, photo thermal absorption measurements on coated samples of different fused silica grades were performed to investigate the influence of basic material properties on the absorption level. High purity, synthetic fused silica is as well the material of choice for optical components designed for DUV applications (wavelength range 160 nm - 260 nm). For higher light intensities, e.g. provided by Excimer lasers, UV photons may generate defect centers that effect the optical properties during usage, resulting in an aging of the optical components (UV radiation damage). Powerful Excimer lasers require optical materials that can withstand photon energy close to the band gap and the high intensity of the short pulse length. The UV transmission loss is restricted to the DUV wavelength range below 300 nm and

  4. Exp erimental studies of multiple pulses in a passively ytterbium-dop ed fib er laser based on graphene-oxide saturable absorb er%氧化石墨烯被动锁模掺镱光纤激光器多脉冲现象的实验研究

    Institute of Scientific and Technical Information of China (English)

    黄诗盛; 王勇刚; 李会权; 林荣勇; 闫培光

    2014-01-01

    The different multiple pulse phenomena are experimentally studied in a passively mode-locked ytterbium-doped fiber laser based on graphene-oxide saturable absorber (GOSA) with net normal dispersion cavity. At the same pump power with different polarization orientations, we observe the multiple pulse phenomena, including harmonic mode-locking of rectangular pulses, dissipative solitons, quasi-harmonic mode-locking, periodical peak modulation, multipulse bunches, multipulse cluster, and chaotic multipulse. The inserted 2 nm narrow bandwidth filter is important for limiting the gain bandwidth and shaping pulses. Adjusting the polarization controller is equivalent to changing the gain in the laser cavity, which is the main reason for the formation of different multiple pulses states. This is the first time that different multiple pulses states have been observed in an-normal-dispersion Yb-doped fiber laser with graphene-oxide saturable absorber. These results could extend the understanding of multiple pulse dynamics in GOSA mode-locked fiber lasers.%利用氧化石墨烯作为可饱和吸收体,在被动锁模全正常色散掺镱光纤激光器中研究了多脉冲的现象。在同一抽运功率不同偏振态下,实验获得了矩形脉冲谐波锁模、耗散孤子谐波锁模、准谐波锁模,脉冲峰值周期性调制,脉冲簇、脉冲束、混沌多重脉冲的多脉冲现象。插入激光腔内的2 nm窄带滤波器具有限制增益带宽、对脉冲塑形、诱导多脉冲产生的作用。调节偏振控制器相当于改变腔内增益,是实现不同类型多脉冲现象的主要原因。本实验研究有利于加深对多脉冲动力学行为在正常色散区域氧化石墨烯锁模掺镱光纤激光器中的理解。

  5. Coupling dynamics for a photonic crystal fib er femtosecond laser nonlinear amplification system%光子晶体光纤飞秒激光非线性放大系统的耦合动力学过程研究∗

    Institute of Scientific and Technical Information of China (English)

    石俊凯; 柴路; 赵晓薇; 李江; 刘博文; 胡明列; 栗岩锋; 王清月

    2015-01-01

    构建了掺镱大模场面积单偏振光子晶体光纤飞秒激光非线性放大系统.讨论了腔内净色散量和抽运功率对振荡级输出参数的影响和振荡级参数对放大级输出参数的影响.在本实验条件下,当腔内净色散量取较大负色散时,振荡级直接输出的脉冲更宽,且携带更少的啁啾.当振荡级抽运4.53 W时,选择最接近变换极限的脉冲作为种子脉冲,放大级在60 W抽运时输出压缩后无基底的短脉冲,宽度为45.7 fs,平均功率28 W.振荡级抽运功率增加到5.08 W,放大级抽运70 W时,获得最高输出功率34.5 W,对应脉宽53.5 fs.%A femtosecond laser single-stage nonlinear amplification system composed of Yb-doped large-mode-area single-polarization photonic crystal fibers is demonstrated. Effects of net cavity dispersion and pump power on oscillator output parameters and the evolution dynamics of the amplified pulse after compression are discussed for different seed pulse parameters. Under the experimental conditions in this paper, the longer and less chirped pulses are obtained with a larger negative net intracavity dispersion in the oscillator. When a nearly-transform-limited pulse is chosen as seed pulse nder the condition of oscillator pump power of 4.53 W, the shortest nearly-pedestal-free amplified pulse is achieved under the amplifier pump power of 60 W after the dispersion is compensated by a grating pair, in which the pulse duration is 45.7 fs with an average power of 28 W at a repetition frequency of 42 MHz. When the oscillator pump power is increased to 5.08 W and most nearly-transform-limited pulses under the pump condition are selected as the seed pulses, the maximum average power of 34.5 W with a duration of 53.5 fs is obtained at an amplifier pump power of 70 W.

  6. Diode-pumped solid-state laser driver experiments for inertial fusion energy applications

    International Nuclear Information System (INIS)

    Although solid-state lasers have been the primary means by which the physics of inertial confinement fusion (ICF) have been investigated, it was previously thought that solid-state laser technology could not offer adequate efficiencies for an inertial fusion energy (IFE) power plant. Orth and co-workers have recently designed a conceptual IFE power plant, however, with a high efficiency diode-pumped solid-state laser (DPSSL) driver that utilized several recent innovations in laser technology. It was concluded that DPSSLs could offer adequate performance for IFE with reasonable assumptions. This system was based on a novel diode pumped Yb-doped Sr5(PO4)3F (Yb:S-FAP) amplifier. Because this is a relatively new gain medium, a project was established to experimentally validate the diode-pumping and extraction dynamics of this system at the smallest reasonable scale. This paper reports on the initial experimental results of this study. We found the pumping dynamics and extraction cross-sections of Yb:S-FAP crystals to be similar to those previously inferred by purely spectroscopic techniques. The saturation fluence for pumping was measured to be 2.2 J/cm2 using three different methods based on either the spatial, temporal, or energy transmission properties of a Yb:S-FAP rod. The small signal gain implies an emission cross section of 6.0x10-20 cm2. Up to 1.7 J/cm3 of stored energy density was achieved in a 6x6x44 mm3 Yb:S-FAP amplifier rod. In a free running configuration diode-pumped slope efficiencies up to 43% were observed with output energies up to ∼0.5 J per 1 ms pulse from a 3x3x30 mm3 rod. When the rod was mounted in a copper block for cooling, 13 W of average power was produced with power supply limited operation at 70 Hz with 500 μs pulses

  7. Laser system for cooling of relativistic C{sup 3+}-ion beams in storage rings; Lasersystem zur Kuehlung relativistischer C{sup 3+}-Ionenstrahlen in Speicherringen

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Tobias

    2015-02-15

    Cold ion beams are essential for many precision experiments at storage rings. While spectroscopic experiments gain from the high energy resolution, collision experiments benefit from the increased luminosity. Furthermore, sympathetic cooling of exotic species is conceivable with the aid of cold ion beams. Besides the long established electron cooling, alternative cooling methods are gaining in importance, especially for high energy particles. In the past, experiments to cool ions with lasers were performed. Because of the matching wavelength and output power, frequency doubled Argon-ion lasers at 257 nm were used during these experiments. Due to the strongly limited scanning potential of these systems, it was not possible to cool the full inertia spread of the ion beams. A new laser system was developed in this thesis because of the lack of commercial alternatives. After the characterization of the system, it was tested during a beamtime at the Experimentierspeicherring (ESR) at the Gesellschaft fuer Schwerionenforschung (GSI). The completely solid state based system delivers up to 180 mW of output power at 257 nm and is modehop free tunable up to 16 GHz in 10 ms at this wavelength. By using efficient diode lasers, the new system consumes considerably less power than comparable Argon-ion lasers. The fundamental wavelength of 1028 nm is amplified up to 16 W with an Yb-doped fiber amplifier. Subsequently, the target wavelength of 257 nm is realized in two consecutive build-up cavities. Another diode laser, stabilized to a wavelength meter, serves as a frequency reference. This new laser system first came to operation during beamtime in August 2012, when relativistic C{sup 3+} ions with β=0.47 were cooled successfully. For the first time it was possible to access the whole inertia spread of a bunched ion beam without electron precooling. In contrast to prior experiments, only the laser frequency was scanned and not the bunching frequency of the ion beam. The results

  8. Efficient sub-Doppler transverse laser cooling of an indium atomic beam

    International Nuclear Information System (INIS)

    Laser cooled atomic gases and atomic beams are widely studied samples in experimental research in atomic and optical physics. For the application of ultra cold gases as model systems for e.g. quantum many particle systems, the atomic species is not very important. Thus this field is dominated by alkaline, earthalkaline elements which are easily accessible with conventional laser sources and have convenient closed cooling transition. On the other hand, laser cooled atoms may also be interesting for technological applications, for instance for the creation of novel materials by atomic nanofabrication (ANF). There it will be important to use technologically relevant materials. As an example, using group III atoms of the periodical table in ANF may open a route to generate fully 3D structured composite materials. The minimal requirement in such an ANF experiment is the collimation of an atomic beam which is accessible by one dimensional laser cooling. In this dissertation, I describe transverse laser cooling of an Indium atomic beam. For efficient laser cooling on a cycling transition, I have built a tunable, continuous-wave coherent ultraviolet source at 326 nm based on frequency tripling. For this purpose, two independent high power Yb-doped fiber amplifiers for the generation of the fundamental radiation at λω = 977 nm have been constructed. I have observed sub-Doppler transverse laser cooling of an Indium atomic beam on a cycling transition of In by introducing a polarization gradient in the linear-perpendicular-linear configuration. The transverse velocity spread of a laser-cooled In atomic beam at full width at half maximum was achieved to be 13.5±3.8 cm/s yielding a full divergence of only 0.48 ± 0.13 mrad. In addition, nonlinear spectroscopy of a 3-level, Λ-type level system driven by a pump and a probe beam has been investigated in order to understand the absorption line shapes used as a frequency reference in a previous two-color spectroscopy experiment

  9. Efficient sub-Doppler transverse laser cooling of an indium atomic beam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae-Ihn

    2009-07-23

    Laser cooled atomic gases and atomic beams are widely studied samples in experimental research in atomic and optical physics. For the application of ultra cold gases as model systems for e.g. quantum many particle systems, the atomic species is not very important. Thus this field is dominated by alkaline, earthalkaline elements which are easily accessible with conventional laser sources and have convenient closed cooling transition. On the other hand, laser cooled atoms may also be interesting for technological applications, for instance for the creation of novel materials by atomic nanofabrication (ANF). There it will be important to use technologically relevant materials. As an example, using group III atoms of the periodical table in ANF may open a route to generate fully 3D structured composite materials. The minimal requirement in such an ANF experiment is the collimation of an atomic beam which is accessible by one dimensional laser cooling. In this dissertation, I describe transverse laser cooling of an Indium atomic beam. For efficient laser cooling on a cycling transition, I have built a tunable, continuous-wave coherent ultraviolet source at 326 nm based on frequency tripling. For this purpose, two independent high power Yb-doped fiber amplifiers for the generation of the fundamental radiation at {lambda}{sub {omega}} = 977 nm have been constructed. I have observed sub-Doppler transverse laser cooling of an Indium atomic beam on a cycling transition of In by introducing a polarization gradient in the linear-perpendicular-linear configuration. The transverse velocity spread of a laser-cooled In atomic beam at full width at half maximum was achieved to be 13.5{+-}3.8 cm/s yielding a full divergence of only 0.48 {+-} 0.13 mrad. In addition, nonlinear spectroscopy of a 3-level, {lambda}-type level system driven by a pump and a probe beam has been investigated in order to understand the absorption line shapes used as a frequency reference in a previous two

  10. 迷迭香(Rosmarinus officinalis)提取残渣栽培糙皮侧耳%Use of Rosemary (Rosmarinus officinalis) Processing Waste for Pleurotus ostreatus Cultivation

    Institute of Scientific and Technical Information of China (English)

    Andrej GREGORI; Bojan PAHOR; Franc POHLEVEN

    2008-01-01

    食品工业中用迷迭香提取抗氧化物质后的残渣(rosemary processing waste RPW)拌入粉碎的玉米粒可以用作栽培糙皮侧耳的培养料.提取抗氧化剂后的迷迭香残渣RPW-1中所含提取残留的丙酮对栽培有害,RPW-1直接栽培糙皮侧耳所获子实体产量比用RPW-2(废料充分通气,去除残存的丙酮)平均低49%.试验中获得最高生物效率(67%)的培养料配比为RPW-2中加入30%(w/w)粉碎的玉米粒(crushed corn seeds CCS)和2%CaCO3.增加培养料中的麸皮(wheat bran WB)比例(降低C/N比)可加快菌丝生长速度,但通常导致子实体产量降低.试验中菌丝生长最快(23 d生长9.9 cm)的培养料配比为RPW-2中添加30%(w/w) CCS 和30% (w/w) WB,/N比为24.%Rosemary processing waste (RPW) generated after extraction of antioxidant components for the food industry, in combination with crushed corn seeds, represented a suitable growth substrate for the cultivation of Pleurotus ostreatus . On average, fruit body yields were 49% lower on substrate mixtures containing RPW1, containing residual acetone from the antioxidant extraction process, compared to substrates incorporating RPW2 which had been allowed to stand in wellaerated conditions in order to remove residual solvent. The highest Biological Efficiency value (67%) were recorded with a substrate mixture containing 30% (w/w) crushed corn seeds (CCS) mixed with RPW2 and 2% CaCO3. Increasing proportions of wheat bran (WB) in the mixtures decreased the C/N ratio, had a positive effect on mycelial growth rates, but generally resulted in lower fruit body yields. The highest vegetative growth rate (9.9 cm in 23 days) was recorded on substrate mixtures with a C/N ratio of 24 and containing RPW2 supplemented with 30% (w/w) CCS and 30% (w/w) WB.

  11. Study of low power deposition of ITO for top emission OLED with facing target and RF sputtering systems

    Energy Technology Data Exchange (ETDEWEB)

    Dangtip, S; Osotchan, T [Department of Physics and NANOTEC centre of excellence at Mahidol University, Faculty of Science, Mahidol University, Bangkok, 10400 (Thailand); Hoshi, Y; Kasahara, Y; Onai, Y; Sawada, Y; Uchida, T [Tokyo Polytechnic University, 1583 Iiyama, Atsugi, Kanagawa, 243-0297 (Japan)], E-mail: tesdt@mahidol.ac.th

    2008-03-15

    Deposition of ITO as top transparent electrode was studied using two deposition systems with and without direct contact to working plasma; namely with conventional RF-magnetron planar (RSS) and pulsed-DC facing target sputtering systems (FTS). Test devices were made on glass substrates and consisted of (from bottom up) ITO/4 Organic Layers/ITO. Depositions were performed at low deposition powers; 30 and 60 watts, to reduce damages by energetic sputtered particles to underlying organic layers. Test devices from both sputtering systems were found to function well. Leakage current density at -5 V reverse bias were relatively constant from 0.3 and 0.4 mA/cm{sup 2} at 30 W and 60 W in FTS, while the values were found to increase from 0.001 to 0.2 mA/cm{sup 2} at 30 W and 60 W in RSS.

  12. Effect of peppermint and citronella essential oils on properties of fish skin gelatin edible films

    Science.gov (United States)

    Yanwong, S.; Threepopnatkul, P.

    2015-07-01

    Fish skin gelatin films incorporated with peppermint and citronella essential oils at difference concentrations (10, 20 and 30% w/w) were prepared by solution casting. Addition of peppermint oil contributed to a significant decrease of tensile strength and Young's modulus, while the percent elongation at break showed an obvious increase except at 30% w/w. On the other hand, addition of citronella oils promoted a great increase of tensile strength and young's modulus, but an intense decrease of the percent elongation at break. At the predetermined content, the film incorporated with citronella oils outperformed the one with peppermint oils in term of water vapor transmission and solubility in water. Thermal properties of gelatin films with citronella oils exhibited an enhancement in heat stability, while the one with peppermint oils showed slight decrease in heat stability. The additions with both of essential oils exhibited excellent antibacterial properties against both Staphylococcus aureus and Escherichia coli.

  13. Addition of Purified Tannin Sources and Polyethylene Glycol Treatment on Methane Emission and Rumen Fermentation in Vitro

    OpenAIRE

    A. Jayanegara; H. P. S. Makkar; Becker, K

    2015-01-01

    The objectives of this experiment were (1) to observe the effects of purified tannins and polyethy-lene glycol (PEG) on in vitro rumen fermentation and methanogenesis, and (2) to assess the accuracy of volatile fatty acid (VFA) profiles in predicting methane emission. Hydrolysable and condensed tannins were extracted and purified from chestnut, sumach, mimosa and quebracho. Hay and concentrate mixture (70:30 w/w, 380 mg) was incubated in Hohenheim glass syringe containing 10 mL rumen liquor +...

  14. How to build your own green laser

    Science.gov (United States)

    Daily, Jared; McLaughlin, Bonnie; Durfee, Dallin; Bergeson, Scott

    2003-05-01

    We describe a frequency-doubled diode-pumped solid-state laser at 532 nm. Our Z-cavity design uses a 30W fiber-coupled 808 nm pump laser, a Nd:YVO4 laser crystal, and an intracavity LBO doubling crystal. The laser produces more than 2W at 532 nm at a cost of around 3k$/W. Improvements in the design and comparison to other designs in the literature are discussed.

  15. Characteristics of a Teflon rod antenna for millimeter and submillimeter wave irradiation on living bodies

    OpenAIRE

    TATSUKAWA, Toshiaki; Doi, Akitaka; TERANAKA, Masato; Takashima, Hitoshi; Goda, Fuminori; Idehara, Toshitaka; Ogawa, Isamu; KANEMAKI, Tomohiro; NISHIZAWA, Seiji; NAMBA, Tunetoyo

    2003-01-01

    The development of a millimeter and submillimeter wave catheter for irradiation on living bodies using a Teflon rod dielectric antenna is described. The power sources of electromagnetic wave are an Impatt oscillator (90 GHz, 0.3 W) and gyrotron (302 GHz, 30 W). Irradiation tests using various Teflon rod dielectric antennas were performed on beef livers. Irradiation results were considered by microwave theory and ray optics.

  16. High-energy passively Q-switched laser operation of Yb:Ca3La2(BO3)4 disordered crystal.

    Science.gov (United States)

    Wang, Lisha; Han, Wenjuan; Pan, Zhongben; Xu, Honghao; Chen, Xiaowen; Liu, Junhai; Yu, Haohai; Zhang, Huaijin

    2016-05-01

    Efficient high-energy passively Q-switched laser operation was demonstrated with Yb:Ca3La2(BO3)4 disordered crystal, producing an average output power of 3.0 W at 1018.7 nm, at a pulse repetition frequency of 5.0 kHz; the resulting pulse energy, duration, and peak power were 600 μJ, 5.3 ns, and 113.2 kW, respectively. PMID:27140354

  17. Стимуляция репаративной регенерации несрастающихся переломов и ложных суставов костей конечностей путем чрескожной лазерной остеоперфорации

    OpenAIRE

    ШУМИЛИН И.И.; Привалов, В. А.

    2006-01-01

    Method of using transcutaneous laser os-teoperforations as well as nearest and remote results of treatment of 51 patients with nonunion fractures and false bone joints have been described in the paper. High-energetic infrared diode laser with the power 30 W and wave length 970 nm was used for osteoperforations. Energy supply to the damaged bone was performed by means of monofiber quartz light pipe with 400 mcm diameter. The results obtained demonstrate low invasiveness and stimulating effect ...

  18. Inhibition of nitric oxide synthesis by systemic N(G)-monomethyl-L-arginine administration in humans

    DEFF Research Database (Denmark)

    Frandsen, U; Bangsbo, J; Langberg, Henning;

    2000-01-01

    We examined whether the formation or the release of the vasodilators adenosine, prostacyclin (PGI(2)) and potassium (K(+)) increase in skeletal muscle interstitium in response to nitric oxide synthase (NOS) inhibition. Five subjects performed one-legged knee extensor exercise at 30 W without (con......-keto-prostaglandin F1alpha concentration in controls was 1.17+/-0.20 ng/ml at rest and increased (p0.05) in L-NAME. The interstitial K(+) concentration in controls increased (p...

  19. Adulticidal activity against Stegomyia aegypti (Diptera: Culicidae) of three Piper spp. Atividade de três Piper spp. contra adultos de Stegomyia aegypti (Diptera: Culicidae)

    OpenAIRE

    Wej Choochote; Udom Chaithong; Kittichai Kamsuk; Eumporn Rattanachanpichai; Atchariya Jitpakdi; Pongsri Tippawangkosol; Dana Chaiyasit; Daruna Champakaew; Benjawan Tuetun; Benjawan Pitasawat

    2006-01-01

    Three Piper species, Piper longum, P. ribesoides and P. sarmentosum, were selected for investigation of adulticidal potential against Stegomyia aegypti, a main vector of dengue and dengue haemorrhagic fever. Successive extraction by maceration with 95% ethanol showed percentage yields of ethanolic extracts, which derived from P. longum, P. ribesoides and P. sarmentosum, of 8.89, 3.21 and 5.30% (w/w), respectively. All Piper extracts illustrated an impressive adulticidal activity when tested a...

  20. Adulticidal activity against Stegomyia aegypti (Diptera: Culicidae) of three Piper spp.

    OpenAIRE

    Choochote Wej; Chaithong Udom; Kamsuk Kittichai; Rattanachanpichai Eumporn; Jitpakdi Atchariya; Tippawangkosol Pongsri; Chaiyasit Dana; Champakaew Daruna; Tuetun Benjawan; Pitasawat Benjawan

    2006-01-01

    Three Piper species, Piper longum, P. ribesoides and P. sarmentosum, were selected for investigation of adulticidal potential against Stegomyia aegypti, a main vector of dengue and dengue haemorrhagic fever. Successive extraction by maceration with 95% ethanol showed percentage yields of ethanolic extracts, which derived from P. longum, P. ribesoides and P. sarmentosum, of 8.89, 3.21 and 5.30% (w/w), respectively. All Piper extracts illustrated an impressive adulticidal activity when tested a...

  1. Topical Delivery of Flurbiprofen from Pluronic Lecithin Organogel

    OpenAIRE

    Pandey M; Belgamwar V; Surana S

    2009-01-01

    The purpose of this research is to formulate and evaluate the suitability of pluronic lecithin organogels containing flurbiprofen for topical application. Four formulations were developed using flurbiprofen, lecithin, Pluronic F127, isopropyl palmitate, water, sorbic acid and potassium sorbate were coded as FL1, FL2, FL3 and FL4. All the formulations carried 30% w/w of lecithin phase and 70% w/w of Pluronic phase. The formulated organogels were evaluated for appearance and feel ...

  2. Effect of Ultrasound on the Compaction of Ibuprofen/Isomalt Systems

    OpenAIRE

    Fini, Adamo; Cavallari, Cristina; Ospitali, Francesca

    2009-01-01

    Six mixtures, containing 10, 20 and 30% w/w ibuprofen and isomalt, were compacted by a traditional or ultrasound-assisted machine and analysed by means of thermal (DSC and TGA) and micro-spectrometry (Raman and FT-IR) techniques. Ultrasound discharge causes melting of ibuprofen powder, transforming into a paste that could not assume the shape of a tablet; when in mixture with isomalt, thermal events, occurring during ultrasound compaction, change the appearance of the particles formed by mill...

  3. Comparison of Ankle Proprioception Between Pregnant and Non Pregnant Women

    OpenAIRE

    Preetha R; John Solomon M

    2011-01-01

    Pregnant women report falls especially during their third trimester. Physiological changes along with ligament laxity can affect the joint proprioception in this population. This study was conducted to compare the ankle proprioception between pregnant and non pregnant women. Thirty pregnant and 30 non pregnant women were included in the study and the position of ankles were recorded by a digital camera placed 60 cms away from the feet of the subject. UTHSCSA Image tool software version 3.0. w...

  4. A power-efficient audio amplifier combining switching and linear techniques

    OpenAIRE

    Zee, van der, KG Kristoffer; Tuijl, van, B.A.J.

    1999-01-01

    Integrated Class D audio amplifiers are very power efficient, but require an external filter which prevents further integration. Also due to this filter, large feedback factors are hard to realise, so that the load influences the distortion- and transfer characteristics. The amplifier presented in this paper consists of a switching part that contains a much simpler filter, and a linear part that ensures a low distortion and flat frequency response. A 30W version was realised. The switching pa...

  5. Role of plant growth promoting rhizobacteria on antioxidant enzyme activities and tropane alkaloid production of Hyoscyamus niger under water deficit stress

    OpenAIRE

    GHORBANPOUR, Mansour; HATAMI, Mehrnaz; Kazem KHAVAZI

    2013-01-01

    This study examined the effects of inoculation with 2 rhizobacteria strains, Pseudomonas putida (PP) and Pseudomonas fluorescens (PF), on growth parameters, chlorophyll, proline, leaf relative water content (RWC), antioxidant enzyme activities (including superoxide dismutase (SOD), peroxidase (POX), and catalase (CAT)), tropane alkaloids (such as hyoscyamine (HYO) and scopolamine (SCO)), and production of Hyoscyamus niger under 3 water deficit stress (WDS) levels, i.e. 30% (W1), 60% (W2), and...

  6. FORMULATION AND IN VITRO EVALUATION OF ARAUCARIA BIDWILLI GUM-BASED SUSTAIN RELEASE MATRIX TABLETS OF DICLOFENAE SODIUM

    Directory of Open Access Journals (Sweden)

    J. ASHOK KUMAR, M.RAJESH, S.MYTHIESH KUMAR,T. GIRIRAJ KULKARNI, V.GOPAL

    2013-10-01

    Full Text Available A gel forming Polysaccharide gum obtained form the bark of Araucaria bidwilli was employed as a matrix sustained release tablet formulation of Diclofenac sodium (a non steroidal anti inflammatory agent. The effect of Araucaria bidwilli gum (Natural and Synthetic polymer Hydroxypropyl methyl cellulose (HPMC K4 M on the release of Diclofenac sodium was studied. The FT-IR spectroscopic studies of drug, gum and mixture indicated no chemical interaction. Six formulations were prepared by wet granulation method containing Araucaria bidwilli gum powder concentration 10% 20% & 30% w\\w and 10% 20% &30% w\\w of HPMC K4 M with sufficient volume of granulating agent Polyvinyl pyrrolene (PVP K 30, Avicel pH101 as diluents, Magnesium stearate and Aerosil is used lubricant and glidant respectively.This study was carried out to find out the difference between synthetic and natural gum and whether synthetic gum can be replaced by natural gums. Physical and technological studies of granules and tablets were compliance with Pharmacopoial standards.The drug release increased with Araucaria bidwilli gum when compared to synthetics polymer concentration .The value of release exponent were found to be almost straight line and regression coefficient value between 0.938 and 0.998.This implies that the release mechanism is diffusion. Formulation F3 ( contained 30% w\\w Araucaria bidwilli gum met the desired requirements for a sustained release dosage form.

  7. 4f and 5d energy levels of the divalent and trivalent lanthanide ions in M{sub 2}Si{sub 5}N{sub 8} (M=Ca, Sr, Ba)

    Energy Technology Data Exchange (ETDEWEB)

    Kate, O.M. ten, E-mail: o.m.tenkate@tudelft.nl [Luminescent Materials Research Group, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands); Energy Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5600MB Eindhoven (Netherlands); Zhang, Z. [Energy Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5600MB Eindhoven (Netherlands); Dorenbos, P. [Luminescent Materials Research Group, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands); Hintzen, H.T. [Energy Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5600MB Eindhoven (Netherlands); Kolk, E. van der [Luminescent Materials Research Group, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands)

    2013-01-15

    Optical data of Sm, Tb and Yb doped Ca{sub 2}Si{sub 5}N{sub 8} and Sr{sub 2}Si{sub 5}N{sub 8} phosphors that have been prepared by solid-state synthesis, are presented. Together with luminescence data from literature on Ce{sup 3+} and Eu{sup 2+} doping in the M{sub 2}Si{sub 5}N{sub 8} (M=Ca, Sr, Ba) hosts, energy level schemes were constructed showing the energy of the 4f and 5d levels of all divalent and trivalent lanthanide ions relative to the valence and conduction band. The schemes were of great help in interpreting the optical data of the lanthanide doped phosphors and allow commenting on the valence stability of the ions, as well as the stability against thermal quenching of the Eu{sup 2+}d-f emission. Tb{sup 3+} substitutes on both a high energy and a low energy site in Ca{sub 2}Si{sub 5}N{sub 8}, due to which excitation at 4.77 eV led to emission from both the {sup 5}D{sub 3} and {sup 5}D{sub 4} levels, while excitation at 4.34 eV gave rise to mainly {sup 5}D{sub 4} emission. Doping with Sm resulted in typical Sm{sup 3+}f-f line absorption, as well as an absorption band around 4.1 eV in Ca{sub 2}Si{sub 5}N{sub 8} and 3.6 eV in Sr{sub 2}Si{sub 5}N{sub 8} that could be identified as the Sm{sup 3+} charge transfer band. Yb on the other hand was incorporated in both the divalent and the trivalent state in Ca{sub 2}Si{sub 5}N{sub 8}. - Graphical abstract: Energy level schemes showing the 4f ground states of the trivalent ( Black-Down-Pointing-Small-Triangle ) and divalent ( Black-Up-Pointing-Small-Triangle ) lanthanide ions and lowest energy 5d states of the trivalent ({nabla}) and divalent ({Delta}) ions with respect to the valence and conduction bands of Ca{sub 2}Si{sub 5}N{sub 8} (left) and Sr{sub 2}Si{sub 5}N{sub 8} (right). Highlights: Black-Right-Pointing-Pointer Construction of energy level schemes of all lanthanides within the M{sub 2}Si{sub 5}N{sub 8} hosts. Black-Right-Pointing-Pointer Construction was done by analyzing existing as well as new

  8. 全光纤结构超短脉冲超连续谱的产生及其特性研究%All- fiber ultra- short super- continuum generation and characters

    Institute of Scientific and Technical Information of China (English)

    于峰; 孙畅; 高静; 匡鸿深; 张晶; 高鹏坤; 葛廷武; 王智勇

    2014-01-01

    Super﹣continuum (SC) is widely used in coherent photography technology, optical spectroscopy analysis, interferometry, etc because of its flat and broad spectrum, high spatial coherence and high power. Super﹣continuum generation could be realized on theory by ultra﹣short pulse laser getting through the high nonlinear medium, accompany with self﹣phase modulation (SPM), stimulated Raman scattering (SRS), four﹣wave mixing (FWM). With the development of fiber technology, Yb- doped ultra﹣short pulse fiber laser, which has high peak power, high optic﹣to﹣optic efficiency, compact structure and small volume was elected as the pump source, and high nonlinear photonic crystal fiber (PCF) as the nonlinear medium for SC. In this paper, a self﹣made amplified mode﹣locked pulse was coupled into a 10m PCF, with 1 040 nm zero dispersion point, to generate 8.13W super﹣continuum by fusing method, during which the key parameters like discharge time, discharge interval, splice loss are seriously optimized to keep the fusing quality well.%超连续光谱以其光谱范围宽、平坦度好、空间相干度高和可实现的较高功率,被广泛应用于相干成像技术、光谱分析、干涉测量等诸多领域。理论上超连续光谱可由超短脉冲通过高非线性介质来实现,期间伴随着自相位调制(SPM)、受激拉曼散射(SRS)、四波混频效应(FWM)。随着光纤技术的发展,利用峰值功率高、光光转换效率高、体积小、结构紧凑的掺Yb超短脉冲光纤激光器作为泵浦源,高非线性的光子晶体光纤作为非线性介质来产生超连续光谱。采用主振荡功率放大结构(MOPA),自行搭建了全光纤锁模脉冲放大器,并通过熔接的方式将其耦合进入长为10 m、零色散点为1040 nm的光子晶体光纤,在对熔接过程中放电时间、放电间隔、熔接损耗等参数进行优化后,获得了8.14 W的超连续光谱。

  9. Facile synthesis of water-soluble carbon nano-onions under alkaline conditions

    OpenAIRE

    Ahmed, Gaber Hashem Gaber; Laíño, Rosana Badía; Calzón, Josefa Angela García; García, Marta Elena Díaz

    2016-01-01

    Carbonization of tomatoes at 240 °C using 30% (w/v) NaOH as catalyst produced carbon onions (C-onions), while solely carbon dots (C-dots) were obtained at the same temperature in the absence of the catalyst. Other natural materials, such as carrots and tree leaves (acer saccharum), under the same temperature and alkaline conditions did not produce carbon onions. XRD, FTIR, HRTEM, UV–vis spectroscopy, and photoluminescence analyses were performed to characterize the as-synthesized carbon nanom...

  10. THE INVESTIGATION OF THE PRODUCT OF GUAIACOL ENZYMATIC OXIDATION IN WATER – DMSO BINARY SOLVENTS

    OpenAIRE

    Сергей Александрович Покрышкин; Константин Григорьевич Боголицын

    2014-01-01

    The investigation on the reaction of enzymatic oxidation of guaiacol as lignin model compound with hydrogen peroxide in the presence of horseradish peroxidase  in water – DMSO binary solvents was done. Using the method of gas chromatography – mass spectrometry the five dimeric products of guaiacol oxidative coupling are identified. The possibility of the using of peroxidase in the mixtures of water with DMSO in the range of solvent compositions up to 30% (w/w) DMSO is shown. For the solvent c...

  11. Low cryogen inventory, forced flow Ne cooling system with room temperature compression stage and heat recuperation

    CERN Document Server

    Shornikov, A; Wolf, A

    2014-01-01

    We present design and commissioning results of a forced flow cooling system utilizing neon at 30 K. The cryogen is pumped through the system by a room-temperature compression stage. To decouple the cold zone from the compression stage a recuperating counterflow tube-in-tube heat exchanger is used. Commissioning demonstrated successful condensation of neon and transfer of up to 30 W cooling power to the load at 30 K using only 30 g of the cryogen circulating in the system at pressures below 170 kPa.

  12. Laser cutting technology using water jet waveguide

    International Nuclear Information System (INIS)

    Laser with water jet is examined to cut in-vessel structure. However, it is necessary to increase the break-up length of water jet to cut a thick plate. Therefore, the effects of the water jet parameter (water pressure, assist gas, laser power) on break-up length were investigated. It was found from observation results of water jet that the longest break-up length is about 135mm under condition of water pressure 40 MPa, laser power 30W and helium assist gas 1L/min. (author)

  13. Effect of Ultrasonic Treatment on the Extracting Activity of Kid Rennet

    Institute of Scientific and Technical Information of China (English)

    ZHANG Fu-xin; LI Lin-qiang

    2005-01-01

    Using 2-3 weeks kid abomasums as materials, the ultrasound intensity, extracting time, NaC1 concentration and pH value in extracting solution and ratio of abomasums to extracting solution were studied by ultrasonic method. The results showed that the main factor affecting kid rennet activity during extraction was ultrasound intensity, and then NaC1concentration, extracting time and ratio of abomasums to extracting solution in order. Kid rennet activity reached peak with ultrasound intensity 30 W cm-2, extraction time 40 min, NaC1 concentration 8%, pH value 3.0, ratio of abomasums to extracting solution 1:15.

  14. Photonic crystal fibers for supercontinuum generation pumped by a gain-switched CW fiber laser

    DEFF Research Database (Denmark)

    Larsen, Casper; Noordegraaf, Danny; Hansen, Kim P.;

    2012-01-01

    Supercontinuum generation in photonics crystal fibers (PCFs) pumped by CW lasers yields high spectral power density and average power. However, such systems require very high pump power and long nonlinear fibers. By on/off modulating the pump diodes of the fiber laser, the relaxation oscillations...... of the laser can be exploited to enhance the broadening process. The physics behind the supercontinuum generation is investigated by sweeping the fiber length, the zero dispersion wavelength, and the fiber nonlinearity. We show that by applying gain-switching a high average output power of up to 30 W...

  15. Nano-Welding of Multi-Walled Carbon Nanotubes on Silicon and Silica Surface by Laser Irradiation

    OpenAIRE

    Yanping Yuan; Jimin Chen

    2016-01-01

    In this study, a continuous fiber laser (1064 nm wavelength, 30 W/cm2) is used to irradiate multi-walled carbon nanotubes (MWCNTs) on different substrate surfaces. Effects of substrates on nano-welding of MWCNTs are investigated by scanning electron microscope (SEM). For MWCNTs on silica, after 3 s irradiation, nanoscale welding with good quality can be achieved due to breaking C–C bonds and formation of new graphene layers. While welding junctions can be formed until 10 s for the MWCNTs on s...

  16. Elastic Electroproduction of $\\rho$ Mesons at HERA

    OpenAIRE

    Adloff, C.; Andreev, V.; Andrieu, B.; Arkadov, V.; Astvatsatourov, A.; Ayyaz, I.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bassler, U.; Bate, P.; Beglarian, A.; Behnke, O.

    2000-01-01

    The elastic electroproduction of rho mesons is studied at HERA with the H1 detector for a photon virtuality in the range 1 Q^2 60 GeV^2 and for a hadronic centre of mass energy in the range 30 W 140 GeV. The shape of the pipi mass distribution in the rho resonance region is measured as a function of Q^2. The full set of rho spin density matrix elements is determined, and evidence is found for a helicity flip amplitude at the level of 8 +- 3 % of the non-flip amplitudes. Measurements are prese...

  17. Primeiro registro de Myriastra purpurea (Ridley, 1884 para a costa brasileira (Porifera, Demospongiae

    Directory of Open Access Journals (Sweden)

    Beatriz Mothes de Moraes

    1984-01-01

    Full Text Available The first record of occurrence of Myriastra purpurea (Ridley, 1884 for the South Atlantic Ocean at shallow areas of the Brazilian coast (State of Rio de Janeiro, Sepetiba Bay: 23º04'53"/44º00'34"W and State of Santa Catarina, Porto Belo: 27º09'12"S/48º29'30"W widely enlarges the distribution of the species, known only from the Indo-Pacific region. Detailed descriptions and ilustrations of the specimens are offered. A table of micrometric measurements and camera lucida drawings of spicules is also offered.

  18. Distribution and relative abundance of large whales in a former whaling ground off eastern South America

    OpenAIRE

    Artur Andriolo; Jesuina M. da Rocha; Zerbini, Alexandre N.; Paulo C. Simões-Lopes; Moreno, Ignacio B.; Alineide Lucena; Daniel Danilewicz; Manuela Bassoi

    2010-01-01

    Ship-based sighting surveys for cetaceans were conducted in the former whaling ground off the northeastern coast of Brazil. The cruises took place in winter and spring of 1998-2001 with the objectives of investigating current distribution and abundance of cetaceans, particularly large whale species taken during whaling. In 1998 the survey were conducted between the parallels 5°30'W and 9°S and the 200 m isobath and the meridian 033°W. A total of about 3,100 nm were surveyed between 1998 and 2...

  19. A high-solids steam injection process for the manufacture of powdered infant milk formula

    OpenAIRE

    Murphy, Eoin; Tobin, John; Roos, Yrjo; Fenelon, Mark

    2013-01-01

    Introduction of more energy efficient processing practices, such as increasing the initial solids content from which powder is manufactured, is of interest to the infant formula industry. This study evaluated the use of an inline rotor-stator mixer followed by direct steam injection to disperse and heat-treat (110 °C, 3 s) high-solids (60% w/w) formulations, for the production of powdered infant milk formula. As a control, 30% w/w infant milk formulations were subjected to a typical process, ...

  20. RHEOLOGICAL PROPERTIES AND THE ENERGETIC VALUE OF WHEAT FLOUR SUBSTITUTED BY DIFFERENT SHARES OF WHITE AND BROWN RICE FLOUR

    OpenAIRE

    Nada Nikolić; Jelena Dodić; Mirjana Mitrović; Miodrag Lazić

    2011-01-01

    In order to produce dough with a lower gluten content, more enriched with rice components and satisfactory rheological properties, the rheological properties, energetic value and cake baking properties of wheat and white or brown rice flour in shares from 3 to 30% (w/w) were investigated in this paper. The water absorption in wheat-rice flour mixtures was lower and decreased to 53.5% and 54.0% along with the increase of the white and the brown rice flour share, respectively, than in wheat fl...

  1. Effect of Microwave Heating on Potato and Tapioca Starches in Water Suspension

    OpenAIRE

    Nurul Nadiah binti Ismail; Uthumporn Utra @ Sapina Abdullah; Syahariza Zainul Abidin

    2015-01-01

    The effects of microwave heating on properties of starch were studied on potato and tapioca starches in water suspension at different temperature (50°C and 60°C). Potato and tapioca starches were adjusted to 30% (w/v) and heat-moisture treated in a microwave oven and conventional heating.Conventional heating was carried out by direct heating the moisture heated sample at 50oC and 60oC while the microwave heating was carried out by microwave oven and the temperature was controlled approximatel...

  2. Effect of Microwave Heating on Potato and Tapioca Starches in Water Suspension

    OpenAIRE

    Nurul Nadiah Ismail; U. Uthumporn; Z. A. Syahariza

    2016-01-01

    Abstract— The effects of microwave heating on properties of starch were studied on potato and tapioca starches in water suspension at different temperature (50°C and 60°C). Potato and tapioca starches were adjusted to 30% (w/v) and heat-moisture treated in a microwave oven and conventional heating.Conventional heating was carried out by direct heating the moisture heated sample at 50ºC and 60ºC while the microwave heating was carried out by microwave oven and the temperature was controlled ap...

  3. Atmospheric Boundary Layer Height Evolution with Lidar in Buenos Aires from 2008 to 2011

    Science.gov (United States)

    Pawelko, Ezequiel Eduardo; Salvador, Jacobo Omar; Ristori, Pablo Roberto; Pallotta, Juan Vicente; Otero, Lidia Ana; Quel, Eduardo Jaime

    2016-06-01

    The analysis of the atmospheric boundary layer top height evolution is obtained from 2008 to 2011 in Buenos Aires using the multiwavelength lidar located at CEILAP (CITEDEF-CONICET) (34°33' S; 58°30' W; 17 m asl). Algorithms recognition based on covariance wavelet transform are applied to obtain seasonal statistics. This method is being evaluated for use in the Lidar Network in Argentina and it is being deployed in Patagonia region currently. The technique operates in real time in both low and high aerosol loads and with almost no human supervision.

  4. Dielectric study of the glass transition of PET/PEN blends

    OpenAIRE

    Sellares, J.; Diego, J A; Canadas, J. C.; Mudarra, M.; Belana, J.; Colomer, P.; Roman, F.; Y. Calventus

    2012-01-01

    An analysis of the glass transition of four materials with similar chemical structures is performed: PET, PEN and two PET/PEN blends (90/10 and 70/30 w/w). During the melt processing of the blends transesterification reactions yield block and random PET/PEN copolymers that act as compatibilizers. The blends obtained in this way have been characterized by 1H-NMR and DSC. A degree of randomness of 0.38 and 0.26 has been found for the 90/10 and 70/30 copolymers. It is shown by DSC that this copo...

  5. 用连铸薄带生产无取向电工钢板的方法

    Institute of Scientific and Technical Information of China (English)

    卢凤喜

    2007-01-01

    @@ 1 发明要点及步骤 钢水成分:w(Si)1.0%~3.5%,w(Al)0.5%,w(Cr)0.1%~3.0%,w(Mn)0.1%~1.0%,w(S)0.01%,w(Se)0.01%,w(N)0.005%,w(C)0.01%,此外还含有其它元素残留量,如w(Ti)、w(Nb)和(或)w(V),数量不超过0.005%.

  6. EFFECT OF CHICKPEA AND PEA FLOUR ADDITION ON THE QUALITATIVE AND SENSORY PARAMETERS OF BAKERY PRODUCTS

    Directory of Open Access Journals (Sweden)

    Veronika Kuchtová

    2012-04-01

    Full Text Available The purpose of this study was to determine chemical composition and functional properties of legume flours (chickpea, pea and fine wheat flour. The effect of chickpea and pea flour incorporation at different levels (10, 20, 30 % w/w on the qualitative parameters and sensory characteristics of bakery product was also investigated. It can be concluded, that incorporation of leguminous flours led to changes of the investigated qualitative and sensory parameters, especially in samples with higher amount of leguminous flour (20 and 30 %. Results showed, that a proper alternative to standard bakery products  are products with 10 % portion of leguminous flour.doi:10.5219/185

  7. Cruise report: regional assessment of ecosystem condition and stressor impacts along the northwestern Gulf of Mexico Shelf. NOAA Ship 'Nancy Foster' NF-11-07-RACOW (August 8-16, 2011)

    OpenAIRE

    Cooksey, Cynthia; Hyland, Jeff; Fulton, Mike

    2011-01-01

    This cruise report is a summary of a field survey conducted along a portion of the U.S. continental shelf in northwestern Gulf of Mexico (GOM), at navigable depths along the coastline seaward to the shelf break (~100m) from about 89°30' W to 95°28' W longitude, August 8 – 16, 2011 on NOAA Ship Nancy Foster Cruise NF-11-07-RACOW. Synoptic sampling of multiple ecological indicators was conducted at each of 34 stations throughout these waters using a random probabilistic sampling design. The ori...

  8. EVALUACIÓN DE LA CAPACIDAD PROBIÓTICA “IN VITRO” DE UNA CEPA NATIVA DE Saccharomyces cerevisiae

    OpenAIRE

    Ángela Ortiz; Joanna Reuto; Erika Fajardo; Sandra Sarmiento; Andrea Aguirre; Gustavo Arbeláez; David Gómez; Balkys Quevedo-Hidalgo

    2008-01-01

    The in vitro probiotic capacity of a native strain of Saccharomyces cerevisiae (A) was evaluated and comparedwith a commercial strain (B) used as a probiotic. The effect of the concentration of sugarcane molasses (10, 20and 30% (w/v)) on the biomass production was investigated and kinetic parameters were determined. The bestmolasses concentration was 20% (w/v) and differences in biomass production on molasses medium betweenstrain A (28 g/L) and control strain B (3 g/L) were observed. In vitro...

  9. INVESTIGATION OF ULTRASOUND WAVES ON PRETREATMENT OF OSMOTIC DEHYDRATION OF CARROT SLICES

    OpenAIRE

    Tahmasebi, Soheila; Mirzaee, Somaye; Kaviyani, Mehdi; Tabrizi, Mahsa; Shariati, Mohammad

    2014-01-01

    In this study, carrot slices were put in glucose osmotic 50% at 1, 2 and 3 hr. Ultrasound waves, frequency 40 kH power 30 w/l, passed through container of osmotic solution and carrot slices. The results revealed that significant increasing of dry matter of sample by using ultrasound waves.pre osmotic time had a significant on dry material by increasing from 1to 3 hr.sample treated by ultrasound waves lost water faster and their final dry solid was significantly more than control (without ultr...

  10. Experimental Investigation of the Heat Transfer in a Room using Night-Time Coling by Mixing Ventilation

    DEFF Research Database (Denmark)

    Jensen, Rasmus Lund; Nørgaard, Jesper; Daniels, Ole;

    2011-01-01

    of full-scale measurements. The efficiency of night-time ventilation depends on the outdoor temperature and the heat transfer between the room air and the building constructions. In a full-scale test room the heat transfer was investigated during 12 hour of discharging by night-time ventilation. Three...... areas and the convective heat transfer coefficient ranged between 5 and 30 W/m2. The ratio of convective to total heat flow from the ceiling depends on the air change rate, ranging from approximately 40% at the low air change rates to approximately 70% at the high air change rate. Even though radiation...

  11. Neuromuscular blockade of slow twitch muscle fibres elevates muscle oxygen uptake and energy turnover during submaximal exercise in humans

    DEFF Research Database (Denmark)

    Krustrup, Peter; Secher, Niels; Relu, Mihai U.;

    2008-01-01

    was slower (P muscle homogenate CP was lowered (P muscle lactate production was similar in CUR and CON (37.8 +/- 4.1 versus 35.2 +/- 6.2 mmol). Estimated total muscle ATP turnover was 19......We tested the hypothesis that a greater activation of fast-twitch (FT) fibres during dynamic exercise leads to a higher muscle oxygen uptake (VO2 ) and energy turnover as well as a slower muscle on-kinetics. Subjects performed one-legged knee-extensor exercise for 10 min at an intensity of 30 W...... fibres, respectively. From 127 s of exercise, muscle VO2 was higher (P muscle VO2 response...

  12. High power amplification of a tailored-pulse fiber laser

    Science.gov (United States)

    Saby, Julien; Sangla, Damien; Caplette, Stéphane; Boula-Picard, Reynald; Drolet, Mathieu; Reid, Benoit; Salin, François

    2013-02-01

    We demonstrate the amplification of a 1064nm pulse-programmable fiber laser with Large Pitch Rod-Type Fibers of various Mode field diameters from 50 to 70 μm. We have developed a high power fiber amplifier at 1064nm delivering up to 100W/1mJ at 15ns pulses and 30W/300μJ at 2ns with linearly polarized and diffraction limited output beam (M²LBO crystals leading to 50W at 532nm and 25W at 355nm with a diffraction limited output. Similar experiments performed at 1032nm are also reported.

  13. High power, continuous-wave, single frequency fiber amplifier at 1091 nm and frequency doubling to 545.5 nm

    OpenAIRE

    Stappel, M.; Steinborn, R.; Kolbe, D.; Walz, J

    2012-01-01

    We present a high power single-frequency ytterbium fiber amplifier system with an output power of 30 W at 1091 nm. The amplifier system consists of two stages, a preamplifier stage in which amplified spontaneous emission is efficiently suppressed (>40 dB) and a high power amplifier with an efficiency of 52 %. Two different approaches of frequency doubling are compared. We achieve 8.6 W at 545.5 nm by single-pass frequency doubling in a MgO-doped periodically poled stoichiometric LiTaO3 and up...

  14. Spin Density Matrix Elements in exclusive production of ω mesons at Hermes

    Science.gov (United States)

    Marianski, B.; Terkulov, A.

    2014-03-01

    Spin density matrix elements have been determined for exclusive ω meson production on hydrogen and deuterium targets, in the kinematic region of 1.0 < Q2 < 10.0 GeV2, 3.0 < W < 6.3 GeV and -t' < 0.2 GeV2. The data, from which SDMEs are determined, were accumulated with the HERMES forward spectrometer during the running period of 1996 to 2007 using the 27.6 GeV electron or positron beam of HERA. A sizable contribution of unnatural parity exchange amplitudes is found for exclusive ω meson production.

  15. Drilling and cutting of thin metal plates in water with radiation of a repetitively pulsed Nd : YAG laser

    Science.gov (United States)

    Glova, A. F.; Lysikov, A. Yu

    2011-10-01

    The conditions of drilling and cutting of 0.15-mm-thick titanium and stainless steel plates in water with the radiation of a repetitively pulsed Nd : YAG laser having the mean power up to 30 W are studied experimentally in the absence of water and gas jets. Dependences of the maximal cutting speed in water on the radiation power are obtained, the cutting efficiency is determined, and the comparison with the conditions of drilling and cutting of plates in air is carried out.

  16. Drilling and cutting of thin metal plates in water with radiation of a repetitively pulsed Nd : YAG laser

    International Nuclear Information System (INIS)

    The conditions of drilling and cutting of 0.15-mm-thick titanium and stainless steel plates in water with the radiation of a repetitively pulsed Nd : YAG laser having the mean power up to 30 W are studied experimentally in the absence of water and gas jets. Dependences of the maximal cutting speed in water on the radiation power are obtained, the cutting efficiency is determined, and the comparison with the conditions of drilling and cutting of plates in air is carried out.

  17. Performance of the Oxford miniature Stirling cycle refrigerator

    Science.gov (United States)

    Bradshaw, T. W.; Delderfield, J.; Werrett, S. T.; Davey, G.

    The 'Oxford Cryocooler' miniature Stirling cycle cooler, a 5-kg mass split-cycle refrigerator developed for use aboard spacecraft, had as its design performance goal the production of 0.5 W of cooling power at 80 K for 30 W of electrical input power. The goal has actually been exceeded, prompting the present discussion of the compressor power budget and displacer losses. Attention is given to graphs of the cold-end temperature vs. compressor input power and cooling power. The cooler is to be used on the Improved Stratospheric and Mesospheric Sounder experiment of the Upper Atmosphere Research Satellite.

  18. Spin Density Matrix Elements in exclusive production of ω mesons at Hermes

    Directory of Open Access Journals (Sweden)

    Marianski B.

    2014-03-01

    Full Text Available Spin density matrix elements have been determined for exclusive ω meson production on hydrogen and deuterium targets, in the kinematic region of 1.0 < Q2 < 10.0 GeV2, 3.0 < W < 6.3 GeV and –t' < 0.2 GeV2. The data, from which SDMEs are determined, were accumulated with the HERMES forward spectrometer during the running period of 1996 to 2007 using the 27.6 GeV electron or positron beam of HERA. A sizable contribution of unnatural parity exchange amplitudes is found for exclusive ω meson production.

  19. Laser treatment of carbon fibre reinforced thermoplastic matrix for adhesive bonding

    Science.gov (United States)

    Genna, S.; Leone, C.; Ucciardello, N.; Giuliani, M.

    2016-05-01

    In the present study, laser surface treatment of CFRP made of PPS thermoplastic matrix by means of a 30 W Q-Switched Yb:YAG fiber laser, is investigated with the aim to improve adhesive bonding. The process parameters pulse power, scanning speed, hatch distance and scanning strategy, were varied to the aim to study the influence of the process condition on the first top resin layer removal and fibre damage. The operating window was experimentally determined. The effectiveness of laser treatment was verified by single lap shear test.

  20. 电纺丝技术制备组织工程食管仿生支架%Preparation of tissue-engineered esophageal scaffolds using electrospinning technology

    Institute of Scientific and Technical Information of China (English)

    於学婵; 沈秋霞; 卢珍珍; 张陈; 邓玲; 胡品; 竺亚斌

    2014-01-01

    BACKGROUND:We have found that oriented fibers can guide the alignment of smooth muscle cells in our previous experiments. Thus, we designed the experiment to prepare wel aligned polymeric fibers using electrospinning technology, aiming at guiding the growth of esophageal smooth muscle cells to maintain cellmorphology and biological function. OBJECTIVE:Using electrospinning technology, to fabricate isotropic and directed nano-fibrous scaffolds made of polycaprolacton, gelatin and silk fibroin. METHODS:Polycaprolacton/silk fibroin fibers at a ratio of 4:1 were prepared with proper parameters, including solution concentration, voltage and injection speed, under the self-made spinning system. The polycaprolacton/gelatin sheets with mass ratio of 2:1, 1:1 and 1:2, respectively, were also fabricated under suitable process parameters. Using the rol er col ector instead of the metal plate, polycaprolacton/gelatin nano-fibrous scaffold with good alignment of fibers was manufactured. RESULTS AND CONCLUSION:The isotropic polycaprolacton/silk fibroin scaffold with fiber diameter of (535.9±126.7) nm was prepared under conditions of solution concentration (0.08 g/mL), injection speed (1.6 mL/h) and voltage (22.5 kV), and these fibers were uniform with no beads. The isotropic polycaprolacton/gelatin scaffold with fiber diameter of (257.9±117.8) nm was prepared under conditions of solution concentration (0.10 g/mL), injection speed (0.8 mL/h) and voltage (22.5 kV). Using the rol er col ector instead of the previous metal plate, polycaprolacton/gelatin (w:w, 1:2) nano-fibrous scaffold with good alignment of fibers was manufactured. The process parameters were 3 000 r/min of rol ing speed, 0.8 mL/h of injection speed and 15 kV of voltage.%背景:前期实验中曾发现纤维的取向可以引导平滑肌细胞的取向生长,因此,设想通过制备取向排列的电纺丝纤维支架,以引导食管平滑肌细胞的有序生长,从而有利于维持肌细胞的形貌及生物功能。目的:以可降解聚己内酯、明胶、丝素蛋白为基材,采用自制的电纺丝系统制备无规和有序的纳米级多孔纤维。方法:将聚己内酯与丝素蛋白以4∶1质量比混合,通过调整溶液浓度、电压、喷射速度等参数,采用自制的电纺丝系统制备聚己内酯/丝素蛋白电纺丝纤维。将聚己内酯与明胶分别以2∶1、1∶1、1∶2质量比混合,在金属平板接收器下,通过调整溶液浓度、电压、喷射速度等参数,采用自制的电纺丝系统制备聚己内酯/明胶无规电纺丝纤维;同时改用滚轴接收装置,通过调整滚轴转数、电压、喷射速度等参数,制备聚己内酯/明胶有序电纺丝纤维。结果与结论:在溶液质量浓度为0.08 g/mL、纺丝液流速1.6 mL/h和电压22.5 kV的条件下,制得了均匀、无串珠、纤维直径为(535.9±126.7) nm的聚己内酯/丝素蛋白多孔纳米纤维膜。在溶液质量浓度为0.10 g/mL、纺丝液流速0.8 mL/h和电压22.5 kV的条件下,制得了无明显串珠、纤维直径为(257.9±117.8) nm的聚己内酯/明胶多孔纳米纤维膜;并且在1∶2质量比时更易成纤维,纤维尺寸更均匀。在滚轴转速3000 r/min。溶液流速0.8 mL/h。电压15 kV的条件下,制得的聚己内酯/明胶有序电纺丝纤维排序更理想,纤维也更均匀。

  1. MR evaluation of pulmonary vein diameter reduction after radiofrequency catheter ablation of atrial fibrillation

    International Nuclear Information System (INIS)

    Fifty consecutive patients aged 52±12 years suffering from drug refractory atrial fibrillation (AF) underwent baseline and post-ablation MR angiography (MRA) at a mean follow-up of 4±3.5 months. Pulmonary vein (PV) disconnection was performed with a maximum energy delivery of 30 W. MRA allowed a two-plane measurement of each PV ostium. After ablation, no significant stenosis was observed, and only 1/194 (0.5%) and 3/194 (2%) PVs had a diameter reduction of 31-40% in the coronal and axial planes, respectively. There was a significant overall post-procedural PV narrowing of 4.9% in the coronal plane and 6.5% in the axial plane (P=ns between both planes). MRA is an efficient technique that can be used in pre- and postoperative evaluation of AF patients. Using a maximal power delivery limited to 30 W, no significant PV stenosis was observed at mid-term follow-up. Late PV anatomical assessment is needed to confirm these results on long-term follow-up. (orig.)

  2. MR evaluation of pulmonary vein diameter reduction after radiofrequency catheter ablation of atrial fibrillation

    Energy Technology Data Exchange (ETDEWEB)

    Anselme, Frederic; Savoure, Arnaud; Mabru, Mikael; Cribier, Alain [Rouen University Hospital, Department of Cardiology, Rouen (France); Gahide, Gerald [Rouen University Hospital, Department of Radiology and Laboratoire QuantIF, Rouen (France); Gerbaud, Edouard [Rouen University Hospital, Department of Cardiology, Rouen (France); Rouen University Hospital, Department of Radiology and Laboratoire QuantIF, Rouen (France); Dacher, Jean-Nicolas [Rouen University Hospital, Department of Radiology and Laboratoire QuantIF, Rouen (France); University Hospital, Department of Radiology, Rouen, Cedex (France)

    2006-11-15

    Fifty consecutive patients aged 52{+-}12 years suffering from drug refractory atrial fibrillation (AF) underwent baseline and post-ablation MR angiography (MRA) at a mean follow-up of 4{+-}3.5 months. Pulmonary vein (PV) disconnection was performed with a maximum energy delivery of 30 W. MRA allowed a two-plane measurement of each PV ostium. After ablation, no significant stenosis was observed, and only 1/194 (0.5%) and 3/194 (2%) PVs had a diameter reduction of 31-40% in the coronal and axial planes, respectively. There was a significant overall post-procedural PV narrowing of 4.9% in the coronal plane and 6.5% in the axial plane (P=ns between both planes). MRA is an efficient technique that can be used in pre- and postoperative evaluation of AF patients. Using a maximal power delivery limited to 30 W, no significant PV stenosis was observed at mid-term follow-up. Late PV anatomical assessment is needed to confirm these results on long-term follow-up. (orig.)

  3. Hydrophobicity, thermal and micro-structural properties of whey protein concentrate-pullulan-beeswax films.

    Science.gov (United States)

    Jafari, Seid Mahdi; Khanzadi, Mehrdad; Mirzaei, Habibollah; Dehnad, Danial; Chegini, Faramarz Khodaian; Maghsoudlou, Yayha

    2015-09-01

    In this research, effects of beeswax (BW) on functional properties of whey protein concentrates (WPC):pullulan (PUL) films were investigated. For this purpose, 0, 10, 20 and 30w/w(glycerol)% BW rates and 30:70, 50:50 and 70:30w/w% WPC:PUL ratios were applied. Films containing 70% WPC:30% PUL (WPC70) and 30% BW (BW30) justified the highest contact angle (92.4°) among all films; SEM micrographs indicated that BW could come toward the surface of films during drying stage and resulted in a higher hydrophobic behavior of bilayer films compared with blend films. WPC70 supplied the lowest T(g) values (36-48 °C) among different proportions of WPC-PUL; the highest melting points were just assured in the absence of BW regardless of combination ratio for WPI:PUL. BW30 films deserved lower roughness rates than BW20 (and even BW10) films, indicating more advantageous microstructure and higher hydrogen connections in BW30 films and justifying similar melting points attained for BW30 films to BW20 or 10 ones. Overall, application of WPC70 and BW30 was recommended to obtain optimum combination of final properties for WPC-PUL-BW bilayer films as SEM exhibited flexible and elastic structures of such films.

  4. Active noise reduction with counter-sound silencers. Final report; Aktive Laermminderung durch Gegenschall. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, A.; Siegel, L. [Wendt SIT GmbH, Ludwigshafen (Germany); Sinambari, G.R. [Fachhochschule Rheinland-Pfalz, Bingen (Germany). Fachbereich Umweltschutz]|[IBS Ingenieurbuero fuer Schall- und Schwingungstechnik GmbH, Ludwigshafen (Germany); Kunz, F. [IBS Ingenieurbuero fuer Schall- und Schwingungstechnik GmbH, Ludwigshafen (Germany); Thorn, U. [Fachhochschule Rheinland-Pfalz, Bingen (Germany). Fachbereich Umweltschutz

    2000-01-01

    In the context of a pilot project, 'ANC ventilation sound absorbers', a conventional sound absorber was successfully replaced by an active silencer, which resulted in a more than 80% by volume reduction of the passive absorption material required. The pressure loss is in the same range as with the conventional system, i.e. about 25 Pa. Widening of the cross-section, as in the conventional system, is not required. The electronic control system consumes about 30 W in the compensation state, i. e. it is not significant. [German] Im Rahmen des Pilotprojektes 'ANC-Lueftungsschalldaempfer' konnte im Zuluftstrang einer Lueftungsanlage an der FH Bingen eine konventioneller Kulissenschalldaempfer durch einen Aktiv-Schalldaempfer erfolgreich substituiert werden. Gegenueber dem substituierten Kulissenschalldaempfer konnte das passive Absorptionsmaterial im ANC-Lueftungsschalldaempfer um ueber 80 Vol% reduziert werden. Der verursachte Druckverlust liegt mit ca. 25 Pa in der Groessenordnung des Druckverlustes des Kulissenschalldaempfers. Dieser erreicht diesen guenstigen Druckverlust aber nur deshalb, weil der Querschnitt im Bereich des Kulissenschalldaempfers entsprechend aufgeweitet wurde, worauf beim ANC-Lueftungsschalldaempfer verzichtet werden konnte. Die elektrische Betriebsleistung der Regelelektronik im Kompensationsfall wurde mit ca. 30W ermittelt und faellt damit nicht nennenswert ins Gewicht. (orig.)

  5. Effects of W Contents in Co Matrix of the Thermal Sprayed WC-Co on the Corrosion Behavior in Molten Zinc

    International Nuclear Information System (INIS)

    This study sought to investigate the reaction of Co-binder containing tungsten with molten zinc. Four kinds of Co-W alloys (pure, 10%W, 20%W, 30%W) were prepared using the powder metallurgy method. The specimens were immersion-tested in molten pure zinc baths at 460 .deg. C. To evaluate the corrosion property in molten zinc, the weight loss of the specimen was measured after the immersion tests at different immersion times (10∼300 min.). Co-10%W alloys, compared with pure cobalt, showed no effect of tungsten addition on the reaction rate in molten zinc. The relationship between the weight loss and the square root of immersion period represents a straight line in both pure cobalt and Co-10%W alloy. The Co-Zn reaction layer in Co-10%W alloy consists of γ 2, γ 1, γ and β 1 phases. The rate of weight loss significantly increases and the weight loss behavior is not well accord with the linear relationship as the tungsten content in the Co-W alloy increases. The β 1 layer was not formed on the Co-20%W alloy and neither was a stable Co-Zn intermetallic compound layer found on the Co-30%W alloy. The main cause of increase in reaction rate with increasing tungsten content is related with the instability of the Co-Zn reaction phases as seen on micro-structural analysis

  6. Effects of W Contents in Co Matrix of the Thermal Sprayed WC-Co on the Corrosion Behavior in Molten Zinc

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Byeong Geun; Hwang, Sun Young [New Metals Research Department, RIST, Pohang (Korea, Republic of); Kim, Kyoo Young [POSTECH, Pohang (Korea, Republic of); Lee, Kee Ahn [Andong National University, Andong (Korea, Republic of)

    2007-08-15

    This study sought to investigate the reaction of Co-binder containing tungsten with molten zinc. Four kinds of Co-W alloys (pure, 10%W, 20%W, 30%W) were prepared using the powder metallurgy method. The specimens were immersion-tested in molten pure zinc baths at 460 .deg. C. To evaluate the corrosion property in molten zinc, the weight loss of the specimen was measured after the immersion tests at different immersion times (10{approx}300 min.). Co-10%W alloys, compared with pure cobalt, showed no effect of tungsten addition on the reaction rate in molten zinc. The relationship between the weight loss and the square root of immersion period represents a straight line in both pure cobalt and Co-10%W alloy. The Co-Zn reaction layer in Co-10%W alloy consists of {gamma} 2, {gamma} 1, {gamma} and {beta} 1 phases. The rate of weight loss significantly increases and the weight loss behavior is not well accord with the linear relationship as the tungsten content in the Co-W alloy increases. The {beta} 1 layer was not formed on the Co-20%W alloy and neither was a stable Co-Zn intermetallic compound layer found on the Co-30%W alloy. The main cause of increase in reaction rate with increasing tungsten content is related with the instability of the Co-Zn reaction phases as seen on micro-structural analysis

  7. Solar photo-Fenton optimisation in treating carbofuran-contaminated water

    Directory of Open Access Journals (Sweden)

    Manuel Alejandro Hernández-Shek

    2012-04-01

    Full Text Available Box-Benkhen design response-surface methodology was developed to optimise photo-Fenton degradation of carbofuran (C12H15NO3 by using a compound parabolic collector pilot plant. The four variables considered in Box-Benkhen design model included carbofuran degradation percentage, initial carbofuran concentration, hydrogen peroxide [H2O2] concentration and iron [Fe2+] concentration. Degradation was monitored by using total organic carbon concentration and high-performance liquid chromatography. A 93.2 mg l-1 carbofuran concentration was completely degraded in t30W = 15 min with 17.1 mg l-1 Fe2+ and 121.6 mg l-1 H2O2. Photo-Fenton degradation led to 76.7% mineralisation. Biodegradability during optimisation was evaluated by using the BOD5/COD ratio; this value increased from 0.04 at the beginning of the process to 0.52 in t30W = 20 min, thereby showing the effectiveness of using biological treatments.

  8. Effects of emulsifier addition on the crystallization and melting behavior of palm olein and coconut oil.

    Science.gov (United States)

    Maruyama, Jessica Mayumi; Soares, Fabiana Andreia Schafer De Martini; D'Agostinho, Natalia Roque; Gonçalves, Maria Inês Almeida; Gioielli, Luiz Antonio; da Silva, Roberta Claro

    2014-03-12

    Two commercial emulsifiers (EM1 and EM2), containing predominantly monoacylglycerols (MAGs), were added in proportiond of 1.0 and 3.0% (w/w) to coconut oil and palm olein. EM1 consisted of approximately 90% MAGs, whereas EM2 consisted of approximately 50% MAGs. The crystallization behavior of these systems was evaluated by differential scanning calorimetry (DSC) and microscopy under polarized light. On the basis of DSC results, it was clear that the addition of EM2 accelerated the crystallization of coconut oil and delayed the crystallization of palm olein. In both oils EM2 addition led to the formation of smaller spherulites, and these effects improved the possibilities for using these fats as ingredients. In coconut oil the spherulites were maintained even at higher temperatures (20 °C). The addition of EM1 to coconut oil changed the crystallization pattern. In palm olein, the addition of 3.0% (w/w) of this emulsifier altered the pattern of crystallization of this fat.

  9. γ-Fe{sub 2}O{sub 3} by sol–gel with large nanoparticles size for magnetic hyperthermia application

    Energy Technology Data Exchange (ETDEWEB)

    Lemine, O.M., E-mail: leminej@yahoo.com [Physics Department, College of Sciences, Al Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh (Saudi Arabia); Omri, K. [Laboratory of Physics of Materials and Nanomaterials Applied at Environment (LaPhyMNE), Faculty of Sciences in Gabes, Gabes (Tunisia); Iglesias, M.; Velasco, V. [Instituto de Magnetismo Aplicado, UCM-ADIF-CSIC (Spain); Crespo, P.; Presa, P. de la [Instituto de Magnetismo Aplicado, UCM-ADIF-CSIC (Spain); Dpto. Física de Materiales, Universidad Complutense de Madrid (Spain); El Mir, L. [Physics Department, College of Sciences, Al Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh (Saudi Arabia); Laboratory of Physics of Materials and Nanomaterials Applied at Environment (LaPhyMNE), Faculty of Sciences in Gabes, Gabes (Tunisia); Bouzid, Houcine [Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Laboratoire des Matériaux Ferroélectriques, Faculté des Sciences de Sfax, Route Soukra Km 3 5, B.P. 802, F-3018 Sfax (Tunisia); Yousif, A. [Department of Physics, College of Science, Sultan Qaboos University, P.O. Box 36, Code 123, Al Khoud (Oman); Al-Hajry, Ali [Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia)

    2014-09-01

    Highlights: • Iron oxides nanoparticles with different sizes are successfully synthesized using sol–gel method. • The obtained nanoparticles are mainly composed of maghemite phase (γ-Fe{sub 2}O{sub 3}). • A non-negligible coercive field suggests that the particles are ferromagnetic. • A mean heating efficiency of 30 W/g is obtained for the smallest particles at 110 kHz and 190 Oe. - Abstract: Iron oxides nanoparticles with different sizes are successfully synthesized using sol–gel method. X-ray diffraction (XRD) and Mössbauer spectroscopy show that the obtained nanoparticles are mainly composed of maghemite phase (γ-Fe{sub 2}O{sub 3}). XRD and transmission electron microscopy (TEM) results suggest that the nanoparticles have sizes ranging from 14 to 30 nm, which are indeed confirmed by large magnetic saturation and high blocking temperature. At room temperature, the observation of a non-negligible coercive field suggests that the particles are ferro/ferrimagnetic. The specific absorption rate (SAR) under an alternating magnetic field is investigated as a function of size, frequency and amplitude of the applied magnetic field. A mean heating efficiency of 30 W/g is obtained for the smallest particles at 110 kHz and 190 Oe, whereas further increase of particle size does not improve significantly the heating efficiency.

  10. Application of Polyethylene Glycol to Promote Cellular Biocompatibility of Polyhydroxybutyrate Films

    Directory of Open Access Journals (Sweden)

    Rodman T. H. Chan

    2011-01-01

    Full Text Available Polyhydroxybutyrate (PHB is a biomaterial with potential for applications in biomedical and tissue engineering; however, its brittle nature and high crystallinity limit its potential. Blending PHB with a variety of PEGs produced natural-synthetic composite films composed of FDA-approved polymers with significant reductions in crystallinity, from 70.1% for PHB films to 41.5% for its composite with a 30% (w/w loading of PEG2000. Blending also enabled manipulation of the material properties, increasing film flexibility with an extension to break of 2.49±1.01% for PHB films and 8.32±1.06% for films containing 30% (w/w PEG106. Significant changes in the film surface properties, as measured by porosity, contact angles, and water uptake, were also determined as a consequence of the blending process, and these supported greater adhesion and proliferation of neural-associated olfactory ensheathing cells (OECs. A growth rate of 7.2×105 cells per day for PHB films with 30% (w/w PEG2000 loading compared to 2.5×105 for PHB films was observed. Furthermore, while cytotoxicity of the films as measured by lactate dehydrogenase release was unaffected, biocompatibility, as measured by mitochondrial activity, was found to increase. It is anticipated that fine control of PEG composition in PHB-based composite biomaterials can be utilised to support their applications in medicinal and tissue engineering applications.

  11. Ultrasound stimulated release of mimosa medicine from cellulose hydrogel matrix.

    Science.gov (United States)

    Jiang, Huixin; Tovar-Carrillo, Karla; Kobayashi, Takaomi

    2016-09-01

    Ultrasound (US) drug release system using cellulose based hydrogel films was developed as triggered to mimosa. Here, the mimosa, a fascinating drug to cure injured skin, was employed as the loading drug in cellulose hydrogel films prepared with phase inversion method. The mimosa hydrogels were fabricated from dimethylacetamide (DMAc)/LiCl solution in the presence of mimosa, when the solution was exposed to ethanol vapor. The US triggered release of the mimosa from the hydrogel matrix was carried out under following conditions of US powers (0-30W) and frequencies (23, 43 and 96kHz) for different mimosa hydrogel matrix from 0.5wt% to 2wt% cellulose solution. To release the drug by US trigger from the matrix, the better medicine release was observed in the matrix prepared from the 0.5wt% cellulose solution when the 43kHz US was exposed to the aqueous solution with the hydrogel matrix. The release efficiency increased with the increase of the US power from 5 to 30W at 43kHz. Viscoelasticity of the hydrogel matrix showed that the hydrogel became somewhat rigid after the US exposure. FT-IR analysis of the mimosa hydrogel matrixes showed that during the US exposure, hydrogen bonds in the structure of mimosa-water and mimosa-cellulose were broken. This suggested that the enhancement of the mimosa release was caused by the US exposure. PMID:27150786

  12. Enhancement of hydrophobicity and tensile strength of muga silk fiber by radiofrequency Ar plasma discharge

    International Nuclear Information System (INIS)

    The hydrophobicity and tensile strength of muga silk fiber are investigated using radiofrequency (RF) Ar plasma treatment at various RF powers (10-30 W) and treatment times (5-20 min). The Ar plasma is characterized using self-compensated Langmuir and emissive probe. The ion energy is observed to play an important role in determining the tensile strength and hydrophobicity of the plasma treated fibers. The chemical compositions of the fibers are observed to be affected by the increase in RF power rather than treatment time. XPS study reveals that the ions that are impinging on the substrates are mainly responsible for the cleavage of peptide bond and side chain of amino acid groups at the surface of the fibers. The observed properties (tensile strength and hydrophobicity) of the treated fibers are found to be dependent on their variation in atomic concentration and functional composition at the surfaces. All the treated muga fibers exhibit almost similar thermal behavior as compared to the virgin one. At RF power of 10 W and treatment time range of 5-20 min, the treated fibers exhibit properties similar to that of the virgin one. Higher RF power (30 W) and the increase in treatment time deteriorate the properties of the fibers due to incorporation of more surface roughness caused by sufficiently high energetic ion bombardment. The properties of the plasma treated fibers are attempted to correlate with the XPS analysis and their surface morphologies.

  13. Influence of Extraction Methods on the Yield of Steviol Glycosides and Antioxidants in Stevia rebaudiana Extracts.

    Science.gov (United States)

    Periche, Angela; Castelló, Maria Luisa; Heredia, Ana; Escriche, Isabel

    2015-06-01

    This study evaluated the application of ultrasound techniques and microwave energy, compared to conventional extraction methods (high temperatures at atmospheric pressure), for the solid-liquid extraction of steviol glycosides (sweeteners) and antioxidants (total phenols, flavonoids and antioxidant capacity) from dehydrated Stevia leaves. Different temperatures (from 50 to 100 °C), times (from 1 to 40 min) and microwave powers (1.98 and 3.30 W/g extract) were used. There was a great difference in the resulting yields according to the treatments applied. Steviol glycosides and antioxidants were negatively correlated; therefore, there is no single treatment suitable for obtaining the highest yield in both groups of compounds simultaneously. The greatest yield of steviol glycosides was obtained with microwave energy (3.30 W/g extract, 2 min), whereas, the conventional method (90 °C, 1 min) was the most suitable for antioxidant extraction. Consequently, the best process depends on the subsequent use (sweetener or antioxidant) of the aqueous extract of Stevia leaves.

  14. Effects of wheat distillers dried grains with solubles with or without protease and β-mannanase on the performance of turkey hen poults.

    Science.gov (United States)

    Opoku, E Y; Classen, H L; Scott, T A

    2015-02-01

    Expansion in bioethanol production has resulted in distillers dried grains with solubles (DDGS) being readily available as a major protein source in the poultry industry. Two experiments were conducted to investigate effects of wheat DDGS (wDDGS) and enzyme on nutrient digestibility and performance of turkey hen poults (7 to 21 d). Two starter diets (0 or 30% wDDGS) were formulated to meet or exceed the nutrient requirements for Hybrid Converter female turkeys. These diets were then mixed in different proportions to obtain 2 additional wDDGS inclusion levels (10 and 20%). In Experiment 1, 0 and 30% wDDGS diets were each subdivided into 3 portions and supplemented with no enzyme (E-), protease (P+; 0.125 g/kg) or β-mannanase (M+; 0.5 g/kg). A total of 144, 7-day-old poults were randomly distributed in groups of 4 in 6 replicate cages per treatment. There were no significant main effects or interactions on feed intake from 7 to 21 d. However, a positive (PWheat DDGS is a valuable energy source and as high as 30% can be incorporated in turkey hen poults (7 to 21 d) diets. PMID:26353159

  15. Influence of Extraction Methods on the Yield of Steviol Glycosides and Antioxidants in Stevia rebaudiana Extracts.

    Science.gov (United States)

    Periche, Angela; Castelló, Maria Luisa; Heredia, Ana; Escriche, Isabel

    2015-06-01

    This study evaluated the application of ultrasound techniques and microwave energy, compared to conventional extraction methods (high temperatures at atmospheric pressure), for the solid-liquid extraction of steviol glycosides (sweeteners) and antioxidants (total phenols, flavonoids and antioxidant capacity) from dehydrated Stevia leaves. Different temperatures (from 50 to 100 °C), times (from 1 to 40 min) and microwave powers (1.98 and 3.30 W/g extract) were used. There was a great difference in the resulting yields according to the treatments applied. Steviol glycosides and antioxidants were negatively correlated; therefore, there is no single treatment suitable for obtaining the highest yield in both groups of compounds simultaneously. The greatest yield of steviol glycosides was obtained with microwave energy (3.30 W/g extract, 2 min), whereas, the conventional method (90 °C, 1 min) was the most suitable for antioxidant extraction. Consequently, the best process depends on the subsequent use (sweetener or antioxidant) of the aqueous extract of Stevia leaves. PMID:25726419

  16. In vitro simulation of transurethral microwave thermal distribution in canine prostate%离体犬前列腺经尿道微波热场的计算机模拟研究

    Institute of Scientific and Technical Information of China (English)

    王颖; 张炽敏; 李嘉; 张中林; 李岭; 苏俊; 王玲

    2008-01-01

    目的 研究前列腺微波热场的分布规律,探讨计算机模拟经尿道前列腺微波辐射热场的可行性.方法 根据前列腺的大小选择微波治疗的最佳时间/功率组合(30 W/180 s),用计算机模拟该时间/功率组合下的微波热场分布情况.对54个离体犬前列腺进行324(54×6)个点次的实际测温,验证计算机模拟热场的准确性.结果 30 W/180 s条件下计算机模拟的温升曲线与实际测温曲线有较好的一致性(占96.29%),两者的时点平面热场分布的规律相符.结论 用计算机模拟离体犬前列腺热场分布可靠准确,这一方法可用于微波治疗前列腺增生时热场的预测和精确调控.

  17. Safety and anti-hyperglycemic efficacy of various tea types in mice.

    Science.gov (United States)

    Han, Manman; Zhao, Guangshan; Wang, Yijun; Wang, Dongxu; Sun, Feng; Ning, Jingming; Wan, Xiachun; Zhang, Jinsong

    2016-01-01

    Tea, a beverage consumed worldwide, has proven anti-hyperglycemic effects in animal models. Better efficacies of tea beverages are frequently associated with high-dose levels, whose safety attracts considerable attention. Based on the inherent nature of tea catechin oxidation, fresh tea leaves are manufactured into diverse tea types by modulating the oxidation degree of catechins. The present study aimed to assess various tea types for their safety properties and anti-hyperglycemic effects. Mice were allowed free access to tea infusion (1:30, w/v) for one week, and the rare smoked tea caused salient adverse reactions, including hepatic and gastrointestinal toxicities; meanwhile, the widely-consumed green and black teas, unlike the rare yellow tea, suppressed growth in fast-growing healthy mice. When mice were fed a high-fat diet and allowed free access to tea infusion (1:30, w/v) for 25 days, only yellow tea significantly reduced blood glucose. Therefore, various teas showed different safety profiles as well as anti-hyperglycemic efficacy strengths. To achieve an effective and safe anti-hyperglycemic outcome, yellow tea, which effectively suppressed high-fat diet-induced early elevation of hepatic thioredoxin-interacting protein, is an optimal choice. PMID:27531374

  18. High-power intrinsically safe-power supply; Leistungsstarke eigensichere Energieversorgungskonzepte

    Energy Technology Data Exchange (ETDEWEB)

    Gerlach, U.; Uehlken, T.; Johannsmeyer, U. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    2003-07-01

    This article describes an innovative intrinsically safe power supply concept. Compared to intrinsically safe DC-supplies generally used in industrial applications - a significant increase in available effective power of up to 30 W is feasible without ignition hazard. Depending on the electrical parameters of the load to be supplied, the source can be designed modular and is surprisingly simple. Hence the field of applications for intrinsic safety can be extended to areas where explosion protection could be realized up to now only by other - mostly more expensive - types of protection. (orig.) [German] Der Beitrag beschreibt das Konzept einer neuartigen leistungsstarken eigensicheren Energieversorgung. Durch die Verwendung von nichtzuendfaehigen elektrischen Wechselgroessen zur Energieuebertragung lassen sich im Vergleich zur in der industriellen Praxis ueblichen DC-Versorgung erstaunlich hohe Wirkleistungen von bis zu 30 W zur Verfuegung stellen. Die Quelle ist in Abhaengigkeit von den elektrotechnischen Randbedingungen der zu versorgenden Last modular aufbaubar und verbluefft durch eine einfache und ueberschaubare Ausfuehrung. Damit laesst sich der Anwendungsbereich der 'Eigensicherheit' auch auf Bereiche ausdehnen, in denen der Explosionsschutz bisher nur durch andere - meist teurere -Zuendschutzarten gewaehrleistet werden konnte. (orig.)

  19. Laser-induced thermotherapy (LITT) - evaluation of a miniaturised applicator and implementation in a 1.0-T high-field open MRI applying a porcine liver model

    Energy Technology Data Exchange (ETDEWEB)

    Streitparth, Florian; Knobloch, Gesine; Rump, J.; Wonneberger, Uta; Hamm, Bernd; Teichgraeber, Ulf [Charite, Humboldt-Universitaet zu Berlin, Department of Radiology, Berlin (Germany); Balmert, Dirk [Somatex Medical Technologies GmbH, Teltow (Germany); Chopra, Sascha [Charite, Humboldt-University, Department of General, Visceral, and Transplantation Surgery, Berlin (Germany); Philipp, Carsten [Elisabeth Klinik, Department of Laser Medicine, Berlin (Germany)

    2010-11-15

    To evaluate the feasibility and safety of a novel LITT applicator for thermal ablation of liver malignancies in 1.0-T high-field open MRI. A miniaturised 6-F double-tubed protective catheter with a closed cooling circuit was used with a flexible laser fibre, connected to a 1,064-nm Nd:YAG laser and evaluated in non-perfused porcine livers (18-30 W for 10-20 min, 2-W and 2-min increments; n = 210/applicator) in reference to an established 9-F system. As a proof of concept, MR-guided LITT was performed in two healthy domestic pigs in high-field open MRI. Ex-vivo, the coagulation volumes induced by the 6-F system with maximum applicable power of 24 W for 20 min (33.0 {+-} 4.4 cm{sup 3}) did not differ significantly from those set with the 9-F system at 30 W for 20 min (35.8 {+-} 4.9 cm{sup 3}) (p = 0.73). A flow-rate of 15 ml/min of the cooling saline solution was sufficient. MR navigation and thermometry were feasible. The miniaturised 6-F applicator can create comparable coagulation sizes to those of the 9-F system. Applicator guidance and online-thermometry in high-field open MRI are feasible. (orig.)

  20. Monitoring lipase-catalyzed butterfat interesterification with rapesee oil by Fourier transform near-infrared spectroscopy

    DEFF Research Database (Denmark)

    Zhang, Hong; Mu, Huiling; Xu, Xuebing

    2006-01-01

    This work demonstrates the application of FT-NIR spectroscopy to monitor the enzymatic interesterification process for butterfat modification. The reactions were catalyzed by Lipozyme TL IM at 70 C for the blend of butterfat/rapeseed oil (70/30, w/w) in a packed-bed reactor. The blend and intere......This work demonstrates the application of FT-NIR spectroscopy to monitor the enzymatic interesterification process for butterfat modification. The reactions were catalyzed by Lipozyme TL IM at 70 C for the blend of butterfat/rapeseed oil (70/30, w/w) in a packed-bed reactor. The blend...... and interesterified fat samples were measured in liquid form at 70 C by transmission mode based FT-NIR at spectra region of 12000-4000 cm-1. Calibrations of FT-NIR for conversion degrees (evaluated by triglyceride profile, which represented by triglyceride peak ratio), and solid fat contents (SFC) of interesterified...

  1. Evaluation and characterization of 30 solar home systems (SHS) Ovonic-Unisolar; Caracterizacion y evaluacion de 30 sistemas FV domiciliarios ovonic-unisolar

    Energy Technology Data Exchange (ETDEWEB)

    Flores, J. Roberto; Agredano, Jaime; Munguia, Gonzalo; Lagunas, Javier; Huacuz, Jorge [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico); Brennan, Steve [Troy, MI (United States)

    2000-07-01

    In this work the first results of the evaluation and characterization of 30 solar home systems (SHS) Ovonic-Unisolar (16 of 30 W and 14 of 60 W of capacity) are presented. The components of the SHS are: One or two PV modules, a charge controller, a nickel metal-hybride (NiMH) battery with a nominal capacity of 85 Ah rated at 3 hours, two or four 8 W lamps, and a CD/CD converter for connecting a radio or a TV W/B a maximum power of 20W. Of all systems evaluated, 29 were installed in three communities of the Oaxaca State, and the other 2 are installed at the Instituto de Investigaciones Electricas (IIE) the laboratory as prototype systems. Before the systems installation at the rural communities, all of them were tested in laboratory. Eight systems installed in the field are being monitoring with data acquisition systems. The main motivation of this projects is to know the behavior of the NiMH battery in the SHS. [Spanish] En este trabajo se presentan los primeros resultados de la caracterizacion y evaluacion de 30 sistemas fotovoltaicos (FV) domiciliarios Ovonic-Unisolar (16 con capacidad de 30 W y 14 con capacidad de 60 W). Los sistemas estan integrados por uno o dos modulos FV de 30 W (dependiendo de la capacidad del sistema), un controlador de carga con termo-interuptor, una bateria del tipo niquel hidruros metalicos (NiHM) con capacidad de 85 Ah a una razon de descarga de 3 horas, 2 o 4 lamparas compactas de alta eficiencia de 8 W y un convertidor CD/CD que permite a los usuarios utilizar una radiograbadora y/o una television B/N con potencia no mayor a 20 W. De estos 30 sistemas FV, 28 se instalaron en 3 comunidades rurales del Estado de Oaxaca y los dos sistemas restantes se tienen instalados en el laboratorio FV del Instituto de Investigaciones Electricas (IIE) como sistemas testigos. Previo a la instalacion en campo, todos los sistemas fueron evaluados en el laboratorio para garantizar su operacion en las comunidades rurales. De los 28 sistemas instalados en

  2. 不同组分的钒酸盐混晶Ybt:YxGd1-t-xVO4光谱与激光性质的比较研究%Comparative study on the spectroscopic and laser properties of mixed vanadates Ybt:YxGd1-t-x VO4 with different compositions

    Institute of Scientific and Technical Information of China (English)

    刘均海; 韩文娟; 张怀金; 王继扬; Xavier Mateos; Valentin Petrov

    2011-01-01

    研究了三种掺Yb钒酸盐混晶Yb0.005:Y0.298Gd0.697VO4,Yb0.007:Y0.407Gd0.586VO4和Yb0.009:Y0.575Gd0.416VO4的室温偏振吸收谱和发射谱.结果表明,最强的吸收和发射相应于π偏振,位于波长985 nm;随组分不同,最大吸收截面σabs=4.8-8.5 × 10-20cm2,吸收带宽9.5-9.9 nm;最大受激发射截面σem=5.8-10.3×10-20cm2.利用高亮度半导体激光器纵向抽运实现了室温下的连续波激光运转.研究发现,不同混晶的激光振荡行为存在很大差异:在谐振腔输出耦合透过率T=2%条件下,Yb0.005:Y0.298Gd0.697VO4和Yb0.009:Y0 575 Gd0 416VO4的激光振荡随抽运功率降低而出现σ,π偏振态的共存和转变;而Yb0.007:Y0.407Gd0.586VO4的激光振荡则保持π偏振态不变.在T=5%情形,Yb0.009:Y0.575Gd0.416VO4的激光振荡为单纯的σ偏振;而Yb0 005:Y0.298 Gd0.697 VO4所产生的激光振荡随抽运功率下降仍出现类似的偏振态变化行为.%The room-temperature polarized absorption and emission spectra of Yb doped mixed vanadates Yb0. 005: Y0.298 Gd0.697 VO4, Yb0.007: Y0.407 Gd0. 586 VO4, and Yb0.009: Y0. 575 Gd0.416 VO4 have been studied. The results show that the strongest absorption and emission, occurring at wavelength of 985 nm, correspond to the r polarization, depending on the composition the maximum absorption cross section ranges from 4. 8 to 8.5 x 10-20 cm2' with bandwidths of 9.5-9.9 nm,whereas the maximum stimulated emission cross section varies in the range of 5.8-10. 3 × 10 -20 cm2. Continuous-wave laser operation has been realized at room temperature with the mixed crystals through longitudinal pumping with a diode laser. It was found that the laser oscillation behavior differs significantly from one mixed crystal to another:in the case of T = 2% (T is the output coupling of the resonator), the coexistence and switching of of, π polarization states occur on reducing the pump power in the laser oscillation of Yb0. 005 :Y0.298 Gd0.697 VO4 and Yb0.009 :Y0.575 Gd0

  3. Study on iron oxide nanoparticles coated with glucose-derived polymers for biomedical applications

    Science.gov (United States)

    Herea, D. D.; Chiriac, H.; Lupu, N.; Grigoras, M.; Stoian, G.; Stoica, B. A.; Petreus, T.

    2015-10-01

    This study reports an approach for a facile one-step synthesis of magnetic nanoparticles (MNPs) coated with glucose-derived polymers (GDP) through a mechanochemical hydrothermal process for biomedical applications. Polymer-coated magnetic nanoparticles (Fe2O3/Fe3O4), with sizes below 10 nm, exhibited superparamagnetic behavior, with a specific magnetization saturation value of about 40 emu/g, and a maximum specific absorption rate (SAR) of 30 W/g in AC magnetic fields. Depending on the intensity of the applied AC magnetic field, a temperature of 42 °C can be achieved in 4-17 min. The surface polymerized layer affords functional hydroxyl groups for binding to biomolecules containing carboxyl, thiol, or amino groups, thereby making the coated nanoparticles feasible for bio-conjugation. In vitro cytotoxicity evaluation pointed out that a relatively high concentration of polymer-coated magnetic nanoparticles (GDP-MNPs) did not induce severe cell alteration, suggesting a good biocompatibility.

  4. Facile synthesis of water-soluble carbon nano-onions under alkaline conditions

    Science.gov (United States)

    Ahmed, Gaber Hashem Gaber; Laíño, Rosana Badía; Calzón, Josefa Angela García

    2016-01-01

    Summary Carbonization of tomatoes at 240 °C using 30% (w/v) NaOH as catalyst produced carbon onions (C-onions), while solely carbon dots (C-dots) were obtained at the same temperature in the absence of the catalyst. Other natural materials, such as carrots and tree leaves (acer saccharum), under the same temperature and alkaline conditions did not produce carbon onions. XRD, FTIR, HRTEM, UV–vis spectroscopy, and photoluminescence analyses were performed to characterize the as-synthesized carbon nanomaterials. Preliminary tests demonstrate a capability of the versatile materials for chemical sensing of metal ions. The high content of lycopene in tomatoes may explain the formation of C-onions in alkaline media and a possible formation mechanism for such structures was outlined. PMID:27335764

  5. Thermo-mechanical behaviors of thermoplastic starch derived from sugar palm tree (Arenga pinnata).

    Science.gov (United States)

    Sahari, J; Sapuan, S M; Zainudin, E S; Maleque, M A

    2013-02-15

    In recent years, increasing environmental concerns focused greater attention on the development of biodegradable materials. A thermoplastic starch derived from bioresources, sugar palm tree was successfully developed in the presence of biodegradable glycerol as a plasticizer. Sugar palm starch (SPS) was added with 15-40 w/w% of glycerol to prepare workable bioplastics and coded as SPS/G15, SPS/G20, SPS/G30 and SPS/G40. The samples were characterized for thermal properties, mechanical properties and moisture absorption on exposure to humidity were evaluated. Morphological studies through scanning electron microscopy (SEM) were used to explain the observed mechanical properties. Generally, the addition of glycerol decrease the transition temperature of plasticized SPS. The mechanical properties of plasticized SPS increase with the increasing of glycerol but up to 30 w/w%. Meanwhile, the water absorption of plasticized SPS decrease with increasing of glycerol. PMID:23399210

  6. Over 0.5 MW green laser from sub-nanosecond giant pulsed microchip laser

    Science.gov (United States)

    Zheng, Lihe; Taira, Takunori

    2016-03-01

    A sub-nanosecond green laser with laser head sized 35 × 35 × 35 mm3 was developed from a giant pulsed microchip laser for laser processing on organic superconducting transistor with a flexible substrate. A composite monolithic Y3Al5O12 (YAG) /Nd:YAG/Cr4+:YAG/YAG crystal was designed for generating giant pulsed 1064 nm laser. A fibercoupled 30 W laser diode centered at 808 nm was used with pump pulse duration of 245 μs. The 532 nm green laser was obtained from a LiB3O5 (LBO) crystal with output energy of 150 μJ and pulse duration of 268 ps. The sub-nanosecond green laser is interesting for 2-D ablation patterns.

  7. Paclitaxel loaded biodegradable poly (sebacic acid-co-ricinoleic acid cylindrical implants for local delivery-in vitro characterization

    Directory of Open Access Journals (Sweden)

    Jagadeesh G Hiremath

    2013-01-01

    Full Text Available The aim of the present research work was to develop the biodegradable polymeric implant for the delivery of antineoplastic drug, paclitaxel (PTX using poly (sebacic-co-recinoleic acid 70:30 w/w. PTX loaded implants were prepared by indigenously developed melt molding technique. Implants were characterized in terms of physico-chemical evaluations, drug content, drug stability and intactness, thermal analysis, drug physical state and crystallinity, surface morphology, hydrolytic degradation, drug release and its kinetics. Prepared implants were yellow and cylindrical in shape with smooth surfaces. Drug in the implants was found to be stable, intact and uniformly dispersed as amorphous state within the polymer matrix. In vitro release, kinetic studies showed zero order and Korsmeyer-Peppas model release being exhibited. Drug release from the polymeric implants was occurred could be as results of diffusion.

  8. Measurement of Deeply Virtual Compton Scattering at HERA

    CERN Document Server

    Andreev, V; Aplin, S; Asmone, A; Babaev, A; Backovic, S; Bähr, J; Baghdasaryan, A; Baranov, P; Barrelet, E; Bartel, Wulfrin; Baudrand, S; Baumgartner, S; Becker, J; Beckingham, M; Behnke, O; Behrendt, O; Belousov, A; Berger, C; Berger, N; Bizot, J C; Boenig, M O; Boudry, V; Bracinik, J; Brandt, G; Brisson, V; Brown, D P; Bruncko, Dusan; Büsser, F W; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Caron, S; Cassol-Brunner, F; Cerny, K; Chekelian, V; Contreras, J G; Coughlan, J A; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; Delcourt, B; Demirchyan, R; de Roeck, A; Desch, Klaus; De Wolf, E A; Diaconu, C; Dodonov, V; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Ellerbrock, M; Elsen, E; Erdmann, W; Essenov, S; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Ferencei, J; Finke, L; Fleischer, M; Fleischmann, P; Fleming, Y H; Flucke, G; Fomenko, A; Foresti, I; Formánek, J; Franke, G; Frising, G; Frisson, T; Gabathuler, Erwin; Garutti, E; Gayler, J; Gerhards, R; Gerlich, C; Ghazaryan, S; Ginzburgskaya, S; Glazov, A; Glushkov, I; Görlich, L; Göttlich, M; Gogitidze, N; Gorbounov, S; Goyon, C; Grab, C; Greenshaw, T; Gregori, M; Grindhammer, G; Gwilliam, C; Haidt, D; Hajduk, L; Haller, J; Hansson, M; Heinzelmann, G; Henderson, R C W; Henschel, H; Henshaw, O; Herrera-Corral, G; Herynek, I; Heuer, R D; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R P; Hovhannisyan, A; Ibbotson, M; Ismail, M; Jacquet, M; Janauschek, L; Janssen, X; Jemanov, V; Jönsson, L B; Johnson, D P; Jung, H; Kapichine, M; Karlsson, M; Katzy, J; Keller, N; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Klimkovich, T; Kluge, T; Knies, G; Knutsson, A; Korbel, V; Kostka, P; Koutouev, R; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Krüger, K; Kuckens, J; Landon, M P J; Lange, W; Lastoviicka, T; Laycock, P; Lebedev, A; Leiner, B; Lendermann, V; Levonian, S; Lindfeld, L; Lipka, K; List, B; Lobodzinska, E; Loktionova, N; López-Fernandez, R; Lubimov, V; Lucaci-Timoce, A I; Lüders, H; Lüke, D; Lux, T; Lytkin, L; Makankine, A; Malden, N; Malinovskii, E I; Mangano, S; Marage, P; Marshall, R; Martisikova, M; Martyn, H U; Maxfield, S J; Meer, D; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, J; Mikocki, S; Milcewicz-Mika, I; Milstead, D; Mohamed, A; Moreau, F; Morozov, A; Morris, J V; Mozer, M U; Müller, K; Murn, P; Nankov, K; Naroska, Beate; Naumann, J; Naumann, T; Newman, P R; Niebuhr, C B; Nikiforov, A; Nikitin, D K; Nowak, G; Nozicka, M; Oganezov, R; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Pascaud, C; Patel, G D; Peez, M; Pérez, E; Perez-Astudillo, D; Perieanu, A; Petrukhin, A; Pitzl, D; Placakyte, R; Pöschl, R; Portheault, B; Povh, B; Prideaux, P; Raicevic, N; Reimer, P; Rimmer, A; Risler, C; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rurikova, Z; Rusakov, S V; Salvaire, F; Sankey, D P C; Sauvan, E; Schatzel, S; Scheins, J; Schilling, F P; Schmidt, S; Schmitt, S; Schmitz, C; Schoeffel, L; Schöning, A; Schröder, V; Schultz-Coulon, H C; Schwanenberger, C; Sedlak, K; Sefkow, F; Shevyakov, I; Shtarkov, L N; Sirois, Y; Sloan, T; Smirnov, P; Soloviev, Yu; South, D; Spaskov, V; Specka, A; Stella, B; Stiewe, J; Strauch, I; Straumann, U; Tchoulakov, V; Thompson, G; Thompson, P D; Tomasz, F; Traynor, D; Truöl, P; Tsakov, I; Tsipolitis, G; Tsurin, I; Turnau, J; Tzamariudaki, E; Urban, M; Usik, A; Utkin, D; Valkár, S; Valkárová, A; Vallée, C; Van Mechelen, P; Van Remortel, N; Vargas-Trevino, A; Vazdik, Ya A; Veelken, C; Vest, A; Vinokurova, S; Volchinski, V; Vujicic, B; Wacker, K; Wagner, J; Weber, G; Weber, R; Wegener, D; Werner, C; Werner, N; Wessels, M; Wessling, B; Wigmore, C; Winter, G G; Wissing, C; Wolf, R; Wünsch, E; Xella, S M; Yan, W; Yeganov, V; Zaicek, J; Zaleisak, J; Zhang, Z; Zhelezov, A; Zhokin, A; Zimmermann, J; Zohrabyan, H G; Zomer, F

    2005-01-01

    A measurement is presented of elastic deeply virtual Compton scattering \\gamma* p \\to \\gamma p made using e^+ p collision data corresponding to a luminosity of 46.5 pb^{-1}, taken with the H1 detector at HERA. The cross section is measured as a function of the photon virtuality, Q^2, the invariant mass of the \\gamma* p system, W, and for the first time, differentially in the squared momentum transfer at the proton vertex, t, in the kinematic range 2 < Q^2 < 80 GeV^2, 30 < W < 140 GeV and |t| < 1 GeV^2. QCD based calculations at next-to-leading order using generalized parton distributions can describe the data, as can colour dipole model predictions.

  9. Optimization of methane conversion to liquid fuels over W-Cu/ZSM-5 catalysts by response surface methodology

    Institute of Scientific and Technical Information of China (English)

    Didi Dwi Anggoro; Istadi

    2008-01-01

    The conversion of methane to liquid fuels is still in the development process. The modified HZSM-5 by loading with Tungsten (W) enhanced its heat resistant performance, and the high reaction temperature (800 ℃) did not lead to the loss of W component by sublimation. The loading of ZSM-5 with Tungsten and Copper (Cu) resulted in an increment in the methane conversion, CO2, and C5+ selectivities. The high methane conversion and C5+ selectivity, and low H2O selectivity are obtained by using W/3.OCu/ZSM-5. The optimization of methane conversion over 3.0 W/3.0Cu/ZSM-5 under different temperature and oxygen concentration using response surface methodology (RSM) are studied. The optimum point for methane conversion is 19% when temperature is 753 ℃, and oxygen concentration is 12%. The highest C5+ selectivity is 27% when temperature is 751 ℃, and oxygen concentration is 11%.

  10. Physical properties of pre-crystallized mixtures of cocoa butter and cupuassu fat

    Energy Technology Data Exchange (ETDEWEB)

    Quast, L.B.; Luccas, V.; Kieckbusch, T.G.

    2011-07-01

    The physical characteristics of pre-crystallized binary mixtures of cocoa butter (Bahia + Indonesian blend) and 5, 10, 15, 20, 25 and 30% (w/w) cupuassu fat were determined. recrystallization was carried out using a lab-scale agitated jacket vessel reactor (700 mL). Samples were submitted to differential scanning calorimetry and X-Ray diffraction. The solid fat content and rupture force were also quantified. The snap values of the crystallized mixture decreased with an increase in the amount of alternative fat. A similar trend was observed with respect to the melting point values. The cocoa butter and cupuassu fat X-ray diffraction patterns confirmed the predominant formation of the a-circumflex polimorph. The addition of up to 30% cupuassu fat did not significantly affect the values of the physical properties when compared to pure cocoa butter (Author).

  11. Impact of tool wear on joint strength in friction stir spot welding of DP 980 steel

    Energy Technology Data Exchange (ETDEWEB)

    Miles, Michael; Ridges, Chris; Hovanski, Yuri; Peterson, Jeremy; Santella, M. L.; Steel, Russel

    2011-09-14

    Friction stir spot welding has been shown to be a viable method of joining ultra high strength steel (UHSS), both in terms of joint strength and process cycle time. However, the cost of tooling must be reasonable in order for this method to be adopted as an industrial process. Recently a new tool alloy has been developed, using a blend of PCBN and tungsten rhenium (W-Re) in order to improve the toughness of the tool. Wear testing results are presented for two of these alloys: one with a composition of 60% PCBN and 40% W-Re, and one with 70% PCBN and 30% W-Re. The sheet material used for all wear testing was 1.4 mm DP 980. Lap shear testing was used to show the relationship between tool wear and joint strength. The Q70 tool provided the best combination of wear resistance and joint strength.

  12. A Primary Study of the Variations of Vertical Radiation with the Beijing 325-m Meteorological Tower

    Institute of Scientific and Technical Information of China (English)

    WANG Yuesi; HU Bo; LIU Guangren

    2005-01-01

    The Beijing 325-m Meteorological Tower (325MT) is used to observe the vertical variation of solar radiation. Results of the experiments indicate that the automatic radiation monitoring system, including a sun tracker and data collection system, works well and all the specifications meet WMO observation standards. The measurement data show that there is a significant radiation decrease from 320 m to the surface, where the difference is only about 30 W m-2 on light air-pollution days, while the maximum reaches about 110 W m-2 when heavy pollution appears near the ground. The global UV radiation decreases on heavy air-pollution days and under poor visibility conditions, and the difference between 300 m and 8 m is larger than on clear days.

  13. Highly nonlinear dispersion-flattened photonic crystal fibers for supercontinuum generation in a telecommunication window

    Science.gov (United States)

    Saitoh, Kunimasa; Koshiba, Masanori

    2004-05-01

    We propose a new structure of highly nonlinear dispersion-flattened (HNDF) photonic crystal fiber (PCF) with nonlinear coefficient as large as 30 W-1km-1 at 1.55 µm designed by varying the diameters of the air-hole rings along the fiber radius. This innovative HNDF-PCF has a unique effective-index profile that can offer not only a large nonlinear coefficient but also flat dispersion slope and low leakage losses. It is shown through numerical results that the novel microstructured optical fiber with small normal group-velocity dispersion and nearly zero dispersion slope offers the possibility of efficient supercontinuum generation in the telecommunication window using a few ps pulses.

  14. Preservation of corn silage sugars with sulfur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.D.; Peart, R.M.; Eckhoff, S.R.; Okos, M.R.

    1985-01-01

    The preservation of corn silage with sulfur dioxide (SO/sub 2/) was studied using SO/sub 2/ dosage levels between 0.0% and 3.0% (w/w), and storage temperatures between 2/sup 0/C and 32/sup 0/C, SO/sub 2/ dosages of 0.3% and above were sufficient to prevent microbial growth in silage during storage in culture tubes for 3 to 6 months at temperatures from 2/sup 0/C and 22/sup 0/C. A dosage of 0.6% was required to preserve silage over 8 months in larger bags at room temperatures. Dry matter losses during ensilement were due to conversion and losses of water soluble sugars in the silage.

  15. Generation of Terahertz Surface Plasmon Polaritons Using Nondiffractive Bessel Beams with Orbital Angular Momentum.

    Science.gov (United States)

    Knyazev, B A; Choporova, Yu Yu; Mitkov, M S; Pavelyev, V S; Volodkin, B O

    2015-10-16

    Bessel vortex beams with topological charges of l=±1 and l=±2 were produced in the terahertz spectral range from a free electron laser Gaussian beam (λ=141  μm) transformed using silicon binary diffractive optical elements. The spatial characteristics of the beams were obtained using a microbolometer array. A radius to path length ratio of 1:100 was achieved for nondiffractive beams with the average power of 30 W. Surface plasmon polaritons (SPPs) on gold-zinc-sulphide-air interfaces were generated due to diffraction of vortex beams on a sample edge. A new effect, a dependence of the efficiency of SPP generation on the direction of the azimuthal component of incident-radiation Poynting vector, was revealed. PMID:26550877

  16. Isolation and fusion of protoplasts from the phytopathogenic fungus Sclerotium rolfsii (Sacc.

    Directory of Open Access Journals (Sweden)

    Sikandar Hayat

    2010-03-01

    Full Text Available Sclerotium rolfsii (Sacc. is a serious plant pathogenic fungus and lacks perfect (basidial stage in production. Protoplast fusion technology was employed to reconstruct fusants from this fungus. Two strains designated as A and R were used. Maximum protoplast yields of 3.8x10(5 /g mycelia and 2.8x10(5 /g mycelia were formed in strains A and R respectively. Osmotic stabilizer sucrose 1M gave maximum yield. Lysing enzyme at the rate of 15mg/ml was found best for yield. Fusion of protoplasts from strains A and R was carried out in fusion media containing PEG 4000 30% (w/v with 0.2mM CaCl2. Four fusants F1, F2, F3 and F4 were recovered. Morphological, physiological and pathogenic characters of fusants were compared with parent strains on carrots, beans and tomato.

  17. SF6气体的回收

    Institute of Scientific and Technical Information of China (English)

    张晓娜

    2012-01-01

      由于SF6断路器具有技术性能好、使用寿命长、维护工作量小的优点,在电力系统得到广泛使用,但随着使用年限的增加,部分SF6断路器进入了A级检修周期,如何进行SF6气体回收及处理成为一道难题.本文通过对LH-6.5Y30W A·Z型SF6气体回收装置的使用简单介绍如何回收SF6气体.

  18. The effectiveness of a high output/short duration radiofrequency current application technique in segmental pulmonary vein isolation for atrial fibrillation

    DEFF Research Database (Denmark)

    Nilsson, Brian; Chen, Xu; Pehrson, Steen;

    2006-01-01

    AIMS: Segmental pulmonary vein (PV) isolation by radiofrequency (RF) catheter ablation has become a curative therapy for atrial fibrillation (AF). However, the long procedure time limits the wide application of this procedure. The aim of the current study was to compare a novel ablation technique...... with a high power output and short application time vs. a conventional technique using a low power output and long application time. METHODS AND RESULTS: The study included 90 consecutive patients (age 53+/-10 years; 66 men). Segmental PV isolation was performed by irrigated RF catheter ablation in...... both groups. In the conventional group (Group 1, 45 patients), the power output was limited to 30 W with a target temperature of 50 degrees C and an RF preset duration of 120 s. In the novel group (Group 2, 45 patients), the maximum power output was preset to 45 W, with a target temperature of 55...

  19. Structural and thermal properties of nanocrystalline CuO synthesized by reactive magnetron sputtering

    International Nuclear Information System (INIS)

    Recent research has shown immense application of metal oxides like CuO, MgO, CaO, Al2O3, etc. in different areas which includes chemical warfare agents, medical drugs, magnetic storage media and solar energy transformation. Among the metal oxides, CuO nanoparticles are of special interest because of their excellent gas sensing and catalytic properties. In this paper we report structural and thermal properties of CuO synthesized by reactive magnetron DC sputtering. The synthesized nanoparticles were characterized by X-ray diffractometer. The XRD result reveals that as DC power increased from 30W to 80W, size of the CuO nanoparticles increased. The same results have been verified through TEM analysis. Thermal properties of these particles were studied using thermogravimetry

  20. Liquid Hydrogen Target for the COMPASS experiment

    CERN Document Server

    Bremer, J; Duday-Chanat, L; Geyer, R; Mallot, G K; Pirotte, O; Vullierme, B

    2014-01-01

    A liquid hydrogen target has been developed for the COMPASS experiment at CERN. The target has a diameter of 40 mm and a length of 2.5 meter, creating an active volume of about 3 liter of liquid hydrogen. The cylindrical part of the target wall is formed by a Kapton® foil strip, wound and glued to a thickness of 0.125 mm. The Kapton® foil is used to minimize the energy loss of the particles, scattered or created within the target volume, crossing the target boundary. The two end-caps enclosing the target volume have been fabricated from Mylar®. The system is cooled with a 30 W at 20 K cryocooler, delivering the cooling capacity for the cool-down as well as for the continuous operation of the system.

  1. Purification, crystallization and preliminary crystallographic analysis of Streptococcus pyogenes laminin-binding protein Lbp

    Energy Technology Data Exchange (ETDEWEB)

    Linke, Christian, E-mail: clin180@ec.auckland.ac.nz [School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland (New Zealand); Caradoc-Davies, Tom T. [School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland (New Zealand); Australian Synchrotron, Clayton, Victoria 3168 (Australia); Proft, Thomas [School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland (New Zealand); Baker, Edward N. [School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland (New Zealand)

    2008-02-01

    The S. pyogenes laminin-binding protein Lbp, which is essential for adhesion to human laminin, has been expressed, purified and crystallized. The laminin-binding protein Lbp (Spy2007) from Streptococcus pyogenes (a group A streptococcus) mediates adhesion to the human basal lamina glycoprotein laminin. Accordingly, Lbp is essential in in vitro models of cell adhesion and invasion. However, the molecular and structural basis of laminin binding by bacteria remains unknown. Therefore, the lbp gene has been cloned for recombinant expression in Escherichia coli. Lbp has been purified and crystallized from 30%(w/v) PEG 1500 by the sitting-drop vapour-diffusion method. The crystals belonged to the monoclinic space group P2{sub 1}, with unit-cell parameters a = 42.62, b = 92.16, c = 70.61 Å, β = 106.27°, and diffracted to 2.5 Å resolution.

  2. Thermal effects in the Input Optics of the Enhanced Laser Interferometer Gravitational-Wave Observatory interferometers.

    Science.gov (United States)

    Dooley, Katherine L; Arain, Muzammil A; Feldbaum, David; Frolov, Valery V; Heintze, Matthew; Hoak, Daniel; Khazanov, Efim A; Lucianetti, Antonio; Martin, Rodica M; Mueller, Guido; Palashov, Oleg; Quetschke, Volker; Reitze, David H; Savage, R L; Tanner, D B; Williams, Luke F; Wu, Wan

    2012-03-01

    We present the design and performance of the LIGO Input Optics subsystem as implemented for the sixth science run of the LIGO interferometers. The Initial LIGO Input Optics experienced thermal side effects when operating with 7 W input power. We designed, built, and implemented improved versions of the Input Optics for Enhanced LIGO, an incremental upgrade to the Initial LIGO interferometers, designed to run with 30 W input power. At four times the power of Initial LIGO, the Enhanced LIGO Input Optics demonstrated improved performance including better optical isolation, less thermal drift, minimal thermal lensing, and higher optical efficiency. The success of the Input Optics design fosters confidence for its ability to perform well in Advanced LIGO.

  3. Optimization of Fluorine Plasma Treatment for Interface Improvement on HfO2/In0.53Ga0.47As MOSFETs

    Directory of Open Access Journals (Sweden)

    Yen-Ting Chen

    2012-03-01

    Full Text Available This paper reports significant improvements in the electrical performance of In0.53Ga0.47As metal-oxide-semiconductor field-effect transistors (MOSFET by a post-gate CF4/O2 plasma treatment. The optimum condition of CF4/O2 plasma treatment has been systematically studied and found to be 30 W for 3–5 min. Approximately 5× reduction in interface trap density from 2.8 × 1012 to 4.9 × 1011 cm−2eV−1 has been demonstrated with fluorine (F incorporation. Subthreshold swing has been improved from 127 to 109 mV/dec. Effective channel mobility has been enhanced from 826 to 1,144 cm2/Vs.

  4. Advances in high-power 9XXnm laser diodes for pumping fiber lasers

    Science.gov (United States)

    Skidmore, Jay; Peters, Matthew; Rossin, Victor; Guo, James; Xiao, Yan; Cheng, Jane; Shieh, Allen; Srinivasan, Raman; Singh, Jaspreet; Wei, Cailin; Duesterberg, Richard; Morehead, James J.; Zucker, Erik

    2016-03-01

    A multi-mode 9XXnm-wavelength laser diode was developed to optimize the divergence angle and reliable ex-facet power. Lasers diodes were assembled into a multi-emitter pump package that is fiber coupled via spatial and polarization multiplexing. The pump package has a 135μm diameter output fiber that leverages the same optical train and mechanical design qualified previously. Up to ~ 270W CW power at 22A is achieved at a case temperature ~ 30ºC. Power conversion efficiency is 60% (peak) that drops to 53% at 22A with little thermal roll over. Greater than 90% of the light is collected at < 0.12NA at 16A drive current that produces 3.0W/(mm-mr)2 radiance from the output fiber.

  5. Effect of amaranth flour (Amaranthus mantegazzianus) on the technological and sensory quality of bread wheat pasta.

    Science.gov (United States)

    Martinez, Cristina S; Ribotta, Pablo D; Añón, María Cristina; León, Alberto E

    2014-03-01

    The technological and sensory quality of pasta made from bread wheat flour substituted with wholemeal amaranth flour (Amaranthus mantegazzianus) at four levels, 15, 30, 40 and 50% w/w was investigated. The quality of the resulted pasta was compared to that of control pasta made from bread wheat flour. The flours were analyzed for chemical composition and pasting properties. Cooking behavior, color, raw and cooked pasta texture, scanning electron microscopy and sensory evaluation were determined on samples. The pasta obtained from amaranth flour showed some detriment of the technological and sensory quality. So, a maximum substitution level of 30% w/w was defined. This is an equilibrium point between an acceptable pasta quality and the improved nutritional and functional properties from the incorporation of amaranth flour.

  6. Obtaining of ceramics biphasic dense and porous

    International Nuclear Information System (INIS)

    Among the bioceramic hydroxyapatite (HAP) and beta-tricalcium phosphate (beta-TCP) are materials commonly used in biomedical field. Their combined properties result in a material with absorbable and at the same time with bioactive surface. Called biphasic ceramics such materials respond more quickly when exposed to physiological environment. In this work, powders of HAP/beta-TCP were obtained by chemical precipitation. After obtaining the post-phase was added at a ratio of 0, 15% and 30w% aqueous solutions of corn starch in order to obtain porous bodies. After mixing the resulting solutions were dried, resigned in tablet form and sintered at 1300 deg C. The initial powder was characterized by X-ray diffraction with Rietveld refinement to quantify the phases present. Bodies-of-evidence has been characterized by calculating the bulk density, X-ray diffraction (XRD), scanning electron microscopy and diametral compression. (author)

  7. A 24 keV liquid-metal-jet x-ray source for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, D. H.; Takman, P. A. C.; Lundstroem, U.; Burvall, A.; Hertz, H. M. [Biomedical and X-Ray Physics, Department of Applied Physics, Royal Institute of Technology/Albanova, SE-10691 Stockholm (Sweden)

    2011-12-15

    We present a high-brightness 24-keV electron-impact microfocus x-ray source based on continuous operation of a heated liquid-indium/gallium-jet anode. The 30-70 W electron beam is magnetically focused onto the jet, producing a circular 7-13 {mu}m full width half maximum x-ray spot. The measured spectral brightness at the 24.2 keV In K{sub {alpha}} line is 3 x 10{sup 9} photons/(s x mm{sup 2}x mrad{sup 2}x 0.1% BW) at 30 W electron-beam power. The high photon energy compared to existing liquid-metal-jet sources increases the penetration depth and allows imaging of thicker samples. The applicability of the source in the biomedical field is demonstrated by high-resolution imaging of a mammography phantom and a phase-contrast angiography phantom.

  8. Mapping of a Hydrological Ice Sheet Drainage Basin on the West Greenland Ice Sheet Margin from ERS-1/2 SAR Interferometry, Ice-Radar Measurement, and Modelling

    DEFF Research Database (Denmark)

    Ahlstrøm, Andreas P.; Bøggild, C.E.; Stenseng, L.;

    2002-01-01

    importance of the potential of the ice overburden pressure compared to the bedrock topography. The meltwater run-off for the basin delineations was modelled with an energy-balance model calibrated with observed ice-sheet ablation and compared to a 25 year time series of measured basin run-off. The standard......The hydrological ice-sheet basin draining into the Tasersiaq lake, West Greenland (66°13'N, 50°30'W), was delineated, First using standard digital elevation models (DEMs) for ice-sheet surface and bedrock, and subsequently using a new high-resolution dataset, with a surface DEM derived from repeat......-track interferometric synthetic aperture radar (SAR) and a bedrock topography derived from an airborne 60 MHz ice-penetrating radar. The extent of the delineation was calculated from a water-pressure potential as a function of the ice-sheet surface and bedrock elevations and a hydraulic factor κ describing the relative...

  9. A diet rich in green and yellow vegetables inhibits atherosclerosis in mice.

    Science.gov (United States)

    Adams, Michael R; Golden, Deborah L; Chen, Haiying; Register, Thomas C; Gugger, Eric T

    2006-07-01

    Although dietary patterns characterized by a high intake of fruits and vegetables are associated with reduced risk of coronary heart disease, the mechanisms involved are uncertain. We determined the effects of a diet rich in green and yellow vegetables on the development of atherosclerosis, the underlying cause of coronary heart disease, in a mouse model of atherosclerosis, the LDL receptor -/-, apolipoprotein B transgenic mouse. The mice were randomized into 2 diet groups: 1) a vegetable-free control diet (n = 53) and 2) the same diet with 30% (w:w) replaced by an equal-parts mixture of freeze-dried peas, green beans, broccoli, corn, and carrots (n = 54). Mice were fed these diets for 16 wk. Aortic atherosclerosis, as estimated by cholesteryl ester content, was reduced 38% (P yellow vegetables inhibits the development of atherosclerosis and may therefore lead to a reduction in the risk of coronary heart disease. PMID:16772454

  10. An overview of the development of lead/acid traction batteries for electric vehicles in India

    Science.gov (United States)

    Sivaramaiah, G.; Subramanian, V. R.

    Electric vehicles (EVs) made an entry into the Indian scene quite recently in the area of passenger transportation, milk floats and other similar applications. The industrial EV market, with various models of fork-lift trucks and platform trucks already in wide use all over India, is a better understood application of EV batteries. The lead/acid traction batteries available in India are not of high-energy density. The best available indigenous lead/acid traction battery has an energy density ( C/5 rate) of 30 W h kg -1 as against 39 W h kg -1 available abroad. This paper reviews the developmental efforts relating to lead/acid traction batteries for electric vehicle applications in India, such as prototype road vehicles, commercial vehicles, rail cars, and locomotives. Due to the need for environmental protection and recognition of exhaustible, finite supplies of petroleum fuel, the Indian government is presently taking active interest in EV projects.

  11. Measurements of local temperature distributions in rod bundles with sodium flow

    International Nuclear Information System (INIS)

    In an electrically heated 19-rod bundle (P/D = 1.30, W/R = 1.40) with sodium flow the three-dimensional temperature fields in the rod clads were measured. The main characteristics of the test section are three adjacent heater rods in the duct wall zone instrumented on four measuring planes and rotatable by 3600 under full power conditions; furthermore spacer grids which are axially movable, and a system allowing to bow one heater rod over the last third of its heated length. The results of measurements of the azimuthal temperature variations of the rotatable rods are presented for different operating conditions (80 2), different spacer grid positions relative to the measuring planes and different bowing positions of one rod. For better understanding of the experimental results cross sections of the 19-rod bundle were prepared. It became evident, that a well-known bundle geometry is very important for the interpretation of the experimental results. (orig.)

  12. Hemostatic efficacy evaluation of radiation crosslinked carboxymethyl kappa-carrageenan and chitosan with varying degrees of substitution

    Science.gov (United States)

    Tranquilan-Aranilla, Charito; Barba, Bin Jeremiah D.; Vista, Jeanina Richelle M.; Abad, Lucille V.

    2016-07-01

    Carboxymethyl derivatives of kappa-carrageenan and chitosan, with varying degrees of substitution, were synthesized by multi-step reaction technique and evaluated for hemostatic efficacy through in vitro assays. FTIR analysis confirmed the presence of carboxymethyl group while 1H NMR spectroscopy indicated degrees of substitution ranging from 1.15-1.58 and 0.45-0.51 for carboxymethyl-κ-carrageenan and carboxymethylchitosan, respectively. Derivatives formed into paste consistency (30% w/v) were successfully crosslinked by gamma irradiation at 30 kGy. The data obtained from whole blood clotting and platelet adhesion assays showed a significant increase in hemostatic capability of κ-carrageenan and chitosan as a consequence of carboxymethylation and crosslinking modifications. In addition, the level of efficacy was comparable to that of a chitosan-based commercial product. These results suggest the potential of κ-carrageenan and chitosan derivatives for development into hemostatic agents.

  13. Modeling and measurements of nocturnal drainage flows along the Front Range of the Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Leone, J.M. Jr.; Gudiksen, P.H.

    1993-05-01

    In support of the DOE ASCOT program Lawrence Livermore National Laboratory has analyzed the wind, temperature, and net radiation measurements acquired by the network of sensors situated within and outside the Coal Creek Canyon drainage area during 1991. It is shown that strong cooling rates, between 50--80 W/m{sup 2}, generate will defined drainage flows with a maximum speed of approximately 6 m/s. A cooling rate of 15--30 W/m{sup 2}, produces a significantly weaker drainage flow and further reduction of the cooling rate results in the failure of any significant drainage flows to form. In an attempt to further understand these flows researchers conducted numerical simulations of two representative flows.

  14. Universal lab on a smartphone: a research of TiOPc thin film as a light dependence electrode

    Science.gov (United States)

    Lin, PoHan; Hsu, Y. H.; Lee, C. K.

    2014-02-01

    In this paper, we study the photoconductivity of a polymer-based TiOPc (Titanium Oxide Phthalocyanine) thin-film for the development of a multi-opto-piezoelectric-valve-array. Using a polymer-based TiOPc thin film to serve as the electrode and a structural layer of a piezoelectric polymer, P(VDF-TrFE) poly[(vinylidenefluoride-co-trifluoroethylene], an optical control valve-array could be developed for manipulating multiple microdroplets for the application of digital microfluidic. In this ongoing project, the dependency of the light intensity, thickness, and composition of spin-coated polymer-based TiOPc thin-film was studied. The experimental finding suggested that a 14 to 55 times resistivity change could be achieved by controlling the film thickness to be between 0.9 μm and 1.5 μm with TiOPc concentration of 20% and 30% w/w compositions.

  15. CTD data from the N.E. Atlantic 31 deg N - 46 deg N, July 1982 Discovery cruise 130

    International Nuclear Information System (INIS)

    This report presents lists and graphs of CTD (conductivity, temperature and depth) data obtained aboard RRS Discovery during July 1982. A series of 14 stations were occupied between approximate 31 deg N 24 deg W and 46 deg N 14 deg W in support of sound ranging trials. A further 20 stations were occupied in the vicinity of Discovery Gap, a channel for deep flow between the Madeira and Iberian basins near 37 deg 30' N 15 deg 30' W. All CTD data were reconciled with reversing thermometer measurements, and salinity and oxygen samples. Root mean square differences for pressure, temperature, salinity and oxygen were 7db, .012 deg C, .007 PSU and 0.3 ml/l in the depth interval 0 to 2,000 db and 6 db, .005 deg C, .003 PSU and .16 ml/l for depths 2,000 to 5,600 db. (author)

  16. Obtaining of ceramics biphasic dense and porous; Obtencao de ceramicas bifasicas densas e porosas

    Energy Technology Data Exchange (ETDEWEB)

    Pallone, E.M.J.A.; Rigo, E.C.S., E-mail: eliria@usp.b [Universidade de Sao Paulo (FZEA/USP), Pirassununga, SP (Brazil). Dept. de Ciencias Basicas; Silva, K.L. [Universidade Estadual de Campinas (FEM/UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica; Rezende, M.E. [Universidade Sao Francisco, Itatiba, SP (Brazil); Fraga, A.F. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Marques, R.F.C. [Universidade Federal de Alfenas (UNIFAL), Pocos de Caldas, MG (Brazil)

    2010-07-01

    Among the bioceramic hydroxyapatite (HAP) and beta-tricalcium phosphate (beta-TCP) are materials commonly used in biomedical field. Their combined properties result in a material with absorbable and at the same time with bioactive surface. Called biphasic ceramics such materials respond more quickly when exposed to physiological environment. In this work, powders of HAP/beta-TCP were obtained by chemical precipitation. After obtaining the post-phase was added at a ratio of 0, 15% and 30w% aqueous solutions of corn starch in order to obtain porous bodies. After mixing the resulting solutions were dried, resigned in tablet form and sintered at 1300 deg C. The initial powder was characterized by X-ray diffraction with Rietveld refinement to quantify the phases present. Bodies-of-evidence has been characterized by calculating the bulk density, X-ray diffraction (XRD), scanning electron microscopy and diametral compression. (author)

  17. High power, continuous-wave, single frequency fiber amplifier at 1091 nm and frequency doubling to 545.5 nm

    CERN Document Server

    Stappel, M; Kolbe, D; Walz, J

    2012-01-01

    We present a high power single-frequency ytterbium fiber amplifier system with an output power of 30 W at 1091 nm. The amplifier system consists of two stages, a preamplifier stage in which amplified spontaneous emission is efficiently suppressed (>40 dB) and a high power amplifier with an efficiency of 52 %. Two different approaches of frequency doubling are compared. We achieve 8.6 W at 545.5 nm by single-pass frequency doubling in a MgO-doped periodically poled stoichiometric LiTaO3 and up to 19.3 W at 545.5 nm by frequency doubling with a lithium-triborate (LBO) crystal in an external enhancement cavity.

  18. All-solid-state continuous-wave frequency doubling Nd:LuVO4/LBO laser with 9.6 W output power at 458 nm

    Science.gov (United States)

    Li, B.; Zhao, L.; Zhang, Y. B.; Zheng, Q.; Zhao, Y.; Yao, Y.

    2013-02-01

    An efficient and compact red laser at 458 nm is generated by intracavity frequency doubling of a continuous wave (CW) laser operation of a diode pumped Nd:LuVO4 laser at 916 nm under the condition of suppression the higher gain transition near 1064 nm. With 30 W diode pump power and a frequency doubling crystal LBO, as high as 9.6 W of CW output power at 458 nm is achieved, corresponding to an optical-to-optical conversion efficiency of 32.0% and the output power stability in 8 hours is better than 2.35%. To the best of our knowledge, this it the highest conversion efficiency of watt-level laser at 458 nm generated by intracavity frequency doubling of a diode pumped Nd:LuVO4 laser at 916 nm.

  19. High-power efficient diode-pumped Nd:YVO4/LiB3O5 457 nm blue laser with 4.6 W of output power.

    Science.gov (United States)

    Xue, Q H; Zheng, Q; Bu, Y K; Jia, F Q; Qian, L S

    2006-04-15

    Continuous-wave 457 blue laser emission at powers as high as 4.6 W is achieved by using a fiber-coupled laser diode array with a power of 30 W to pump 0.1 at. % low-doped bulk Nd:YVO4 crystal, with intracavity frequency doubling in a 15 mm long type I critical phase-matched LiB3O5 (LBO) crystal in a compact three-fold cavity with a length of less than 100 mm. The optical-optical conversion efficiency is greater than 15.3%, and the stability of the output power is better than 3% for an hour. PMID:16625906

  20. Laser resonant-ionization mass spectrometry of actinides

    International Nuclear Information System (INIS)

    Laser resonant-ionization mass spectrometry has been used to determine small amounts of actinides. The high sensitivity and selectivity of this method has been achieved by three-step photoionization of actinide atoms followed by time-of-flight measurement. The laser system for photoionization consists of a pulsed copper vapour laser of 30 W average power at a pulse repetition rate of 6.5 kHz which is coupled to three dye lasers. The time-of-flight spectrometer has a mass resolution of about 2500. Resonance signals with count rates of several kilohertz were obtained with actinide samples of 1010-1012 atoms yielding a detection limit of 108 atoms in the sample. With some improvements a detection sensitivity of about 106 atoms of plutonium, americium and curium should be reached. (orig.)

  1. Laser resonance ionization mass spectrometry as a sensitive analytical method for actinides and technetium

    International Nuclear Information System (INIS)

    Laser resonance ionization mass spectrometry has been investigated as a method for the determination of trace amounts of actinides and technetium. A high sensitivity and selectivity have been achieved by three-step photoionization of the elements in the atomic state followed by time-of-flight measurement for mass analysis. The system for photoionization consists of three dye lasers which are pumped simultaneously by a copper vapour laser of 30 W average power at a pulse repetition rate of 6.5 KHz. The time-of-flight spectrometer has a mass resolution better than 2500. By ionization via autoionization states and by saturation in each excitation step a detection limit of less than 108 atoms of actinides or of technetium in the sample can be reached. (author)

  2. 1.1.5. Synthesis and characterization of silver(I complexes with ligands having anti-inflammatory properties

    Directory of Open Access Journals (Sweden)

    M. I. Azócar*, H. Muñoz, P. Levin, N. Dinamarca, G. Gómez, A. Ibañez, M.T. Garland and M. A. Paez

    2014-04-01

    Full Text Available Five water soluble silver(I  complex with Ibuprofen (AgIbu, Naproxen (AgNap,  Mefenamic acid (AgMef, acetyl salicylic acid(AgAsp and salicylic acid (AgSal were synthesized and characterized by elemental analysis, FT-IR, 1H and 13C NMR. Data suggest coordination of the ligand to Ag(I through the oxygen atom of the carboxylic group. AgAsp was obtained as a mixture of AgAsp and Ag(I-2-hydroxybenzoate (AgSal due to decomposition by thermal and hydrolysis of acetylsalicylic acid into salicylic acid. AgSal structure was confirmed by FT-IR, NMR and X-ray diffraction. Synthesized compounds were tested toward UV-radiation (258 nm, 30 W and compared with AgCl in order to characterize their light sensibility.

  3. Parametric Study on the Dynamic Heat Storage Capacity of Building Elements

    DEFF Research Database (Denmark)

    Artmann, Nikolai; Manz, H.; Heiselberg, Per

    2007-01-01

    of onedimensional heat conduction in a slab with convective boundary condition was applied to quantify the dynamic heat storage capacity of a particular building element. The impact of different parameters, such as slab thickness, material properties and the heat transfer coefficient was investigated, as well...... as their interrelation. The potential of increasing thermal mass by using phase change materials (PCM) was estimated assuming increased thermal capacity. The results show a significant impact of the heat transfer coefficient on heat storage capacity, especially for thick, thermally heavy elements. The storage capacity...... of a 100 mm thick concrete slab was found to increase with increasing heat transfer coefficients as high as 30 W/m2K. In contrast the heat storage capacity of a thin gypsum plaster board was found to be constant when the heat transfer coefficient exceeded 3 W/m2K. Additionally, the optimal thickness...

  4. Refractive index matching to develop transparent polyaphrons: Characterization of immobilized proteins.

    Science.gov (United States)

    Ward, Keeran; Stuckey, David C

    2016-06-01

    Refractive index matching was used to create optically transparent polyaphrons to enable proteins adsorbed to the aphron surface to be characterized. Due to the significant light scattering created by polyaphrons, refractive index matching allowed for representative circular dichroism (CD) spectra and acceptable structural characterization. The method utilized n-hexane as the solvent phase, a mixture of glycerol and phosphate buffer (30% [w/v]) as the aqueous phase, and the non-ionic surfactants, Laureth-4 and Kolliphor P-188. Deconvolution of CD spectra revealed that the immobilized protein adapted its native conformation, showing that the adsorbed protein interacted only with the bound water layer ("soapy shell") of the aphron. Isothermal calorimetry further demonstrated that non-ionic surfactant interactions were virtually non-existent, even at the high concentrations used (5% [w/v]), proving that non-ionic surfactants can preserve protein conformation. PMID:26952359

  5. Transparent Conducting ITO Films Reactively Sputtered on Polyethylene Terephtalate Substrates Without Heat Treatment

    Science.gov (United States)

    Kim, Hyun Hoo; Lee, Moo Young; Kim, Kwang Tae; Yoon, Sahng Hyun

    Indium tin oxide (ITO) films have been deposited on PET and glass substrates by DC reactive magnetron sputtering without post-deposition thermal treatment. High quality films have been deposited by optimizing the sputtering parameters. The influence of the working gas pressure, DC power, and oxygen partial pressure has been investigated. The lowest resistivity of ITO films deposited on PET substrates was 6×10-4Ωcm. It has been obtained at a working pressure of 3 mTorr and DC power of 30 W. The sheet resistance and optical transmittance of these films were 22 Ω/square and 84%, respectively. The best values of figures of merit for the electrical and optical chardcteristics such as T/Rsh and T10/Rsh are approximately 38.1 and 7.95 (×10-3 Ω-1), respectively.

  6. Enhanced performance of a wide-aperture copper vapour laser with hydrogen additive in neon buffer gas

    Indian Academy of Sciences (India)

    Bijendra Singh; V V Subramaniam; S R Daultabad; Ashim Chakraboty

    2010-11-01

    A wide-aperture copper vapour laser was demonstrated at ∼ 10 kHz rep-rate with hydrogen additive in its buffer gas. Maximum power in excess of ∼ 50 W (at 10 kHz) was achieved by adding 1.96% hydrogen to the neon buffer gas at 20 mbar total gas pressure. This increase in output power was about 70% as compared to ∼ 30 W achieved with pure neon at 5.5 kHz rep-rate. The 70% enhancement achieved was significantly higher than the maximum reported value of 50% so far in the literature. The enhancement was much higher (about 150%) as compared to its 20 W power at 10 kHz rep-rate using pure neon as the standard CVL operation.

  7. 一例起搏器植入术后使用高频电刀的护理

    Institute of Scientific and Technical Information of China (English)

    李雅文

    2012-01-01

    1病例简介患者,男,59岁,曾因窦性心动过缓和间歇房室阻滞于2010年9月植入Adapta ADD01起搏器,程控显示各项参数正常,已开启MVP模式,同年12月发现右腮腺肿物住院.行右侧腮腺浅叶肿物切除术.使用高频电刀,型号Force E2,Valley Lab,USA;电源电压交流220 V,输出功率30 W,频率450 KHz.采用"点射"方式行电切或电凝操作,每次持续时间<20 s.

  8. Bronchography in dogs. Comparative study with two barium sulphate solutions

    International Nuclear Information System (INIS)

    Two solutions of barium sulphate, 60 and 30% w/v, were compared with the ''overflow'' Bronchographic method. Two groups of eight healthy adult does of both sexes, weighing 7 to 18 kg were used for the study. The dogs were anaesthetised with thiopentone sodium 2% (20 mg/kg iv). After intubation, each dog received contrast medium by a catheter connected to a syringe, in a 9 mi dose. Two series of two x-rays plates were taken in left lateral recumbent, 3 and 6 min after administering the contrast medium and in ventrodorsal projection, 30 sec. later. The x-ray plates obtained were analysed and compared intra and inter group considering the advance speed of the contrast medium, the radiographic density and outlines. Adverse reactions were controlled

  9. EFFECT OF THE ADDITION OF COMMON BEAN FLOUR ON THE COOKING QUALITY AND ANTIOXIDANT CHARACTERISTICS OF SPAGHETTI

    Directory of Open Access Journals (Sweden)

    José Alberto

    2012-10-01

    Full Text Available Pasta is a nutritionally unbalanced food, due to its low fat and fiber and low value of its protein. It is considered an adequate vehicle for food supplementation with minerals, proteins and other healthy components such as bioactive compounds present in common beans. The effect of composite pasta (wheat – common bean; 30 % w/w on the cooking quality (optimal cooking time, cooking loss, weight loss, firmness, color, total phenolic content, antioxidant capacity by DPPH and ORAC assays and phenolic acid profile was investigated. According to the quality parameters, pasta added with bean flour was less hard with respect to the pasta made from durum wheat. The total phenolic content and antioxidant capacity by DPPH and ORAC assays were higher in the pasta with common bean flour than in the pasta control. Also, more phenolic acids were identified in cooked pasta containing common bean flour as analyzed by HPLC.

  10. Experimental investigation on CFRP milling by low power Q-switched Yb:YAG laser source

    Science.gov (United States)

    Genna, S.; Tagliaferri, F.; Papa, I.; Leone, C.; Palumbo, B.

    2016-05-01

    In the present study, laser milling of CFRP plate by means of a 30W Q-Switched Yb:YAG fiber laser is investigated through statistical analysis. Milling tests were performed at the nominal power changing the pulse power; the scanning speed, the hatch distance and the released energy. Design of Experiments (DoE) and ANalysis Of VAriance (ANOVA) were applied with the aim to improve the process performances in term of material removal rate and heat affected zone extension. The results show that, the adopted laser is an effective solution for the CFRP milling. Moreover, adopting an accurate approach to the problem, process variability and material damages can be easily reduced.

  11. A composição dos bandos mistos de aves na Mata Atlântica da Serra de Paranapiacaba, no sudeste brasileiro Mixed flocks of birds in Atlantic Rain Forest in Serra de Paranapiacaba, southeastern Brazil

    OpenAIRE

    C. G. MACHADO

    1999-01-01

    Bandos mistos de aves são agrupamentos de duas ou mais espécies cuja formação e coesão se devem a interações comportamentais entre seus integrantes. Este estudo investigou a composição dos bandos mistos na Mata Atlântica do Parque Estadual Intervales, no alto da Serra de Paranapiacaba, SP, Brasil (24º12' a 24º25'S; 48º03' a 48º30'W). Foram feitas visitas mensais de abril de l990 a março de l991. A cada bando contatado registrava-se o número de indivíduos, composição e distribuição específica ...

  12. Formulation and Characterization of Fast Disintegrating Tablet of Aceclofenac by using Sublimation Method

    Directory of Open Access Journals (Sweden)

    Kalpesh Gaur

    2011-01-01

    Full Text Available In the present work, fast disintegrating tablets of Aceclofenac were prepared by subliming method with a view to enhance patient compliance. In this paper, two super-disintegrants, viz., crospovidone and sodium starch glycolate were used in different ratio (2-8 % w/w with camphor (30 % w/w as subliming agent. The prepared batches of tablets were evaluated for thickness, weigh variation, hardness, friability, drug content uniformity, wetting time, water absorption ratio, in-vitro disintegration time and in-vitro drug release. Based on disintegration time (approximately 21 second, three formulations were tested for the in-vitro drug release pattern (in pH 7.4 phosphate buffer. Among the three promising formulations, the formulation prepared by using 8% w/w of crospovidone and emerged as the overall best formulation based on the in-vitro drug release characteristics.

  13. Impact of BaB2O4 growth method on frequency conversion to the deep ultra-violet

    Science.gov (United States)

    Deyra, L.; Maillard, A.; Maillard, R.; Sangla, D.; Salin, F.; Balembois, F.; Kokh, A. E.; Georges, P.

    2015-12-01

    In this article, we report how the growth method used for barium beta-borate β-BaB2O4 (BBO) impacts its high power second harmonic generation properties in the deep-UV. We compared a BBO crystal grown by flux (Top Seeded Solution Growth or TSSG) and a BBO crystal grown by the Czochralski (CZ) method. We first characterized their transparency properties, then we measured their single-pass second harmonic conversion efficiencies with both a low average power and a high average power nanosecond pulsed lasers. We show that both crystals have comparable linear absorption and conversion efficiencies at low power, whereas in a high power experiment, the CZ-grown BBO yields higher conversion efficiency than the TSSG grown BBO. With a 30 W, 150 kHz, 8 ns green laser, the use of a CZ BBO led at best to a 40% increase in available average output power at 257 nm.

  14. Biodrying for mechanical-biological treatment of wastes: a review of process science and engineering.

    Science.gov (United States)

    Velis, C A; Longhurst, P J; Drew, G H; Smith, R; Pollard, S J T

    2009-06-01

    Biodrying is a variation of aerobic decomposition, used within mechanical-biological treatment (MBT) plants to dry and partially stabilise residual municipal waste. Biodrying MBT plants can produce a high quality solid recovered fuel (SRF), high in biomass content. Here, process objectives, operating principles, reactor designs, parameters for process monitoring and control, and their effect on biodried output quality are critically examined. Within the biodrying reactors, waste is dried by air convection, the necessary heat provided by exothermic decomposition of the readily decomposable waste fraction. Biodrying is distinct from composting in attempting to dry and preserve most of biomass content of the waste matrix, rather than fully stabilise it. Commercial process cycles are completed within 7-15 days, with mostly H(2)O((g)) and CO(2) loses of ca. 25-30% w/w, leading to moisture contents of MBT process operators, regulators and end-users of SRF. PMID:19216072

  15. EFFECT OF SOME PLANT EXTRACT AGAINST SEED BORNE INFECTION OF COLLECTOTRICHUM DESTRUCTIVUM ON VIGNA UNIGUCULATA L.

    Directory of Open Access Journals (Sweden)

    Umesh P. Mogle1 and

    2012-06-01

    Full Text Available The cowpea, Vigna unguiculata L. Walp is an ancient food crop, suffering from many fungal diseases. Collectotrichum destructivum is a harmful seed borne pathogen causing disease to the cowpea plant. Control of seed borne infection would be a possible means of reducing losses due to this disease, attempts were made, fungal species isolated from cowpea seeds were used as inocula. The effects of leaf extracts of Argemone mexicana L., Semecarpus anacardium L., Cassia fistula L., Tephrosia purpurea (L. Pers., were evaluated for the control of Collectotrichum destructivum on seeds of cowpea. The seeds were soaked in sterile distilled water extract (10, 20 and 30%, w/v of the leaves for 5, 10 and 15 h. All these plant extracts had significant inhibitory growth effect on the fungal pathogen. Argemone mexicana extract was more effective followed by Semecarpus anacardium, Cassia fistula and Tephrosia purpurea plant extracts and compared favorably with benomyl in the control of the pathogen.

  16. Effect of sulfonation and diethanolamine addition on the mechanical and physicochemical properties of SEPS copolymer

    Science.gov (United States)

    Patiño, D.; Correa, E.; Acevedo-Morantes, M.

    2016-02-01

    Modification techniques have been developed to achieve changes in the processing of polymers, and modification of their mechanical, thermal and morphological properties, as well as their hydrophobicity and conductivity. Sulfonation improves ion conductivity, antistatic behaviour, hydrophilicity and solubility of the polymers. These characteristics are related to the presence of sulfonic groups in the polymer matrix. This research project focuses on the evaluation of mechanical, physical and chemical properties of membranes that are based on a sulfonated Styrene-Ethylene-Propylene-Styrene (SEPS) copolymer. The membranes were functionalized with diethanolamine at 5, 15 and 30% w/w, to separate carbon dioxide. FTIR and XRD analyses were used to characterize the membranes. The sulfonated-loaded membrane with 15% of diethanolamine showed the best results in each characterization.

  17. High-power picoseconds 355 nm laser by third harmonic generation based on CsB3O5 crystal

    Science.gov (United States)

    Guo, L.; Wang, G. L.; Zhang, H. B.; Cui, D. F.; Wu, Y. C.; Lu, L.; Zhang, J. Y.; Huang, J. Y.; Xu, Z. Y.

    2007-07-01

    We report on the high average power third harmonic generation (THG) of a mode-locked picosecond laser in a CsB3O5 (CBO) crystal. The picosecond laser beam at 1064 nm is produced by a home-made 30 W master oscillator power-amplifier (MOPA) Nd:YVO4 laser system. The maximum THG output at 355 nm is up to 5.4 W. We also investigate the phase matching angle at different temperatures. During high power operation, the temperature of the CBO crystal is set at a high temperature of more than 100 °C. The THG system has shown a fine long-term stability for more than two months of operation.

  18. Stereolithography of three-dimensional bioactive poly(ethylene glycol) constructs with encapsulated cells.

    Science.gov (United States)

    Arcaute, Karina; Mann, Brenda K; Wicker, Ryan B

    2006-09-01

    Stereolithography (SL) was used to fabricate complex 3-D poly(ethylene glycol) (PEG) hydrogels. Photopolymerization experiments were performed to characterize the solutions for use in SL, where the crosslinked depth (or hydrogel thickness) was measured at different laser energies and photoinitiator (PI) concentrations for two concentrations of PEG-dimethacrylate in solution (20% and 30% (w/v)). Hydrogel thickness was a strong function of PEG concentration, PI type and concentration, and energy dosage, and these results were utilized to successfully fabricate complex hydrogel structures using SL, including structures with internal channels of various orientations and multi-material structures. Additionally, human dermal fibroblasts were encapsulated in bioactive PEG photocrosslinked in SL. Cell viability was at least 87% at 2 and 24 h following fabrication. The results presented here indicate that the use of SL and photocrosslinkable biomaterials, such as photocrosslinkable PEG, appears feasible for fabricating complex bioactive scaffolds with living cells for a variety of important tissue engineering applications.

  19. Prediction of the performance of a solar water detoxification system under Malaysian climatic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Jubran, B.A.; Ismail, A.F.; Pervez, T. [International Islamic University Malaysia, Dept. of Mechanical Engineering, Kuala Lumpur (Malaysia)

    2000-07-01

    This paper reports a prediction study for computing the ultra violet (UV) light received by two types of solar collector systems used in solar detoxification systems under Malaysian climatic conditions. Furthermore, the average daily yield outputs of two types of solar detoxification are predicted. The predicted results indicate that the average daily UV light insolation throughout the year in Malaysia is almost constant with values of 40 and 30 W/m{sup 2} for flat plate and compound parabolic concentrator (CPC) collectors, respectively. The average daily yield outputs of the solar detoxification systems investigated are 1000 l/m{sup 2} for the flat plate collector and 600 l/m{sup 2} for the CPC collector with unit costs per 1000 gallons of 36 US dollars and 42 US dollars for flat plate and CPC collectors, respectively. (Author)

  20. Effect of three interventional bronchoscopic methods on tracheal stenosis and the formation of granulation tissues in dogs

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jie; WANG Ting; WANG Juan; PEI Ying-hua; XU Min; WANG Yu-ling; ZHANG Xia; WANG Chen

    2010-01-01

    Background Therapeutic approaches for tracheal stenosis caused by the formation of exuberant granulation tissues usually include electrocautery, mechanical dilation, laser therapy, argon plasma coagulation (APC), cryotherapy and stent placement. However, restenosis after stent insertion remains a significant limitation. We examined the efficacy of three different approaches, including induction of mechanical lesions, APC performed with different powers or durations and cryotherapy, to identify the method that limited the formation of granulation tissue. Methods Twelve specially bred research mongrel dogs were divided into three groups. In group 1 (four dogs) mild (procedure 1; two dogs) or moderate (procedure 2; two dogs) damage was induced mechanically. Group 2 (six dogs) received APC at different powers or durations (procedure 3:30 W, 1 amis; procedure 4:30 W, 2 cm/s; procedure 5:25 W, 3 cm/s). Group 3 (two dogs) received cryotherapy (procedure 6: two freeze-thaw cycles of 30 seconds). Uncovered self-expandable metallic stents were inserted in all dogs to maintain a continuous stimulus to the trachea mucosa. Dogs were monitored for 4 weeks and the relationship between granulation tissue proliferation and method used was analyzed. Results In group 1, granulation tissue growth increased with more severe mechanical damage. The growth of granulation tissue in group 2 was more pronounced than in group 1, and both dogs in procedure 3 died because of severe stenosis. In this group, the formation of granulation tissue decreased with decreasing power and duration. In group 3, no obvious granulation tissue was found at week 4. Conclusions Lesions and stimuli from a foreign body (the stent) are two important factors that lead to overgrowth of granulation tissue. Thermal lesions, such as APC, seem to induce greater granulation tissue growth and cartilage damage compared with mechanical and cryotherapy lesions. Cryotherapy in combination with mechanical dilation may be a safe

  1. Real-time UV imaging of drug diffusion and release from Pluronic F127 hydrogels.

    Science.gov (United States)

    Ye, Fengbin; Yaghmur, Anan; Jensen, Henrik; Larsen, Susan W; Larsen, Claus; Østergaard, Jesper

    2011-07-17

    The objective of this study was to introduce and evaluate UV imaging technology for real-time characterization of drug diffusion in and release from hydrogels. Piroxicam and human serum albumin diffusion in Pluronic F127 hydrogel was monitored by measuring the absorbance of light passing through the diffusion cell at 26°C, thus providing real-time concentration maps (7×3 mm imaging area) within the gel as a function of time. Apparent diffusion coefficients were obtained on the basis of Fick's second law. Piroxicam and human serum albumin diffusivities in 20% (w/w) F127 gel were 8 and 24 times lower than those determined in the phosphate buffer (pH 7.4). The effect of increasing polymer concentration (20%, 25% and 30% (w/w)) on piroxicam diffusion was further investigated. The decreasing diffusion rate with increasing F127 concentration agreed well with small-angle X-ray scattering (SAXS) measurements. UV imaging was also successfully applied to monitor piroxicam release from 30% (w/w) F127 gel into a stirred aqueous buffer solution, providing simultaneous information on gel dissolution rate, change in thickness of gel-aqueous boundary layer as well as the release of piroxicam into bulk aqueous phase. The current study indicates that UV imaging has great potential for measuring drug diffusion in and release from gel matrices. Compared to the currently used conventional techniques, this technology has several advantages including high information content, non-intrusive measurements without the need for labeling, flexibility with respect to experimental design and simplicity of operation. PMID:21550399

  2. Inorganic ion exchangers based on manganese and potassium for recovery and removal of pollutant metals of aqueous effluents; Trocadores ionicos inorganicos a base de manganes e potassio para recuperacao e remocao de metais poluentes de efluentes aquosos

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Jacinete Lima dos

    2001-07-01

    This work presents a study on the synthesis, characterization and ion exchange properties of inorganic ion exchangers based on manganese and potassium. The ion exchangers were synthesized by calcination of the mixture of manganese(II) oxalate and potassium oxalate and were characterized by granulometer distribution analysis, X-ray powder diffraction, infrared spectroscopy and scanning electron microscopic. From the data obtained in characterization it was observed that exist two distinguished groups of these materials. The first group belong to ion exchangers with up to 30% w/w potassium and the second group formed by the ion exchangers with more than 30% w / w of content of potassium in their compositions. The studies of adsorption of these materials showed that the adsorption of Cd{sup 2+} is a function of the following parameters as pH, concentration of Cd{sup 2+}, time of contact between the ion exchangers the concentration of the Cd{sup 2+} solution and the interference of other ions like Ni{sup 2+}. The great pH of adsorption for these materials occur in pH 9, the study of the influence of the cadmium concentration in the adsorption showed that for a group of exchangers the adsorption decreases with the increase of cadmium concentration and for the other group the adsorption increases with the increase of cadmium concentration. The kinetics of adsorption occur in a contact time between the ion exchangers and the Cd{sup 2+} solutions relatively short, at about 15 minutes is necessary to establish the equilibrium. The presence of Ni{sup 2+} as interfering ion decreases the adsorption of cadmium of 99,7% to 65%. These inorganic ion exchangers showed be good exchangers for Cd{sup 2+}. (author)

  3. High drug load, stable, manufacturable and bioavailable fenofibrate formulations in mesoporous silica: a comparison of spray drying versus solvent impregnation methods.

    Science.gov (United States)

    Hong, Shiqi; Shen, Shoucang; Tan, David Cheng Thiam; Ng, Wai Kiong; Liu, Xueming; Chia, Leonard S O; Irwan, Anastasia W; Tan, Reginald; Nowak, Steven A; Marsh, Kennan; Gokhale, Rajeev

    2016-01-01

    Encapsulation of drugs in mesoporous silica using co-spray drying process has been recently explored as potential industrial method. However, the impact of spray drying on manufacturability, physiochemical stability and bioavailability in relation to conventional drug load processes are yet to be fully investigated. Using a 2(3) factorial design, this study aims to investigate the effect of drug-loading process (co-spray drying and solvent impregnation), mesoporous silica pore size (SBA-15, 6.5 nm and MCM-41, 2.5 nm) and percentage drug load (30% w/w and 50% w/w) on material properties, crystallinity, physicochemical stability, release profiles and bioavailability of fenofibrate (FEN) loaded into mesoporous silica. From the scanning electronic microscopy (SEM) images, powder X-ray diffraction and Differential scanning calorimetry measurements, it is indicated that the co-spray drying process was able to load up to 50% (w/w) FEN in amorphous form onto the mesoporous silica as compared to the 30% (w/w) for solvent impregnation. The in vitro dissolution rate of the co-spray dried formulations was also significantly (p = 0.044) better than solvent impregnated formulations at the same drug loading. Six-month accelerated stability test at 40 °C/75 RH in open dish indicated excellent physical and chemical stability of formulations prepared by both methods. The amorphous state of FEN and the enhanced dissolution profiles were well preserved, and very low levels of degradation were detected after storage. The dog data for the three selected co-spray-dried formulations revealed multiple fold increment in FEN bioavailability compared to the reference crystalline FEN. These results validate the viability of co-spray-dried mesoporous silica formulations with high amorphous drug load as potential drug delivery systems for poorly water soluble drugs. PMID:24853963

  4. Optimal design of a hybridization scheme with a fuel cell using genetic optimization

    Science.gov (United States)

    Rodriguez, Marco A.

    Fuel cell is one of the most dependable "green power" technologies, readily available for immediate application. It enables direct conversion of hydrogen and other gases into electric energy without any pollution of the environment. However, the efficient power generation is strictly stationary process that cannot operate under dynamic environment. Consequently, fuel cell becomes practical only within a specially designed hybridization scheme, capable of power storage and power management functions. The resultant technology could be utilized to its full potential only when both the fuel cell element and the entire hybridization scheme are optimally designed. The design optimization in engineering is among the most complex computational tasks due to its multidimensionality, nonlinearity, discontinuity and presence of constraints in the underlying optimization problem. this research aims at the optimal utilization of the fuel cell technology through the use of genetic optimization, and advance computing. This study implements genetic optimization in the definition of optimum hybridization rules for a PEM fuel cell/supercapacitor power system. PEM fuel cells exhibit high energy density but they are not intended for pulsating power draw applications. They work better in steady state operation and thus, are often hybridized. In a hybrid system, the fuel cell provides power during steady state operation while capacitors or batteries augment the power of the fuel cell during power surges. Capacitors and batteries can also be recharged when the motor is acting as a generator. Making analogies to driving cycles, three hybrid system operating modes are investigated: 'Flat' mode, 'Uphill' mode, and 'Downhill' mode. In the process of discovering the switching rules for these three modes, we also generate a model of a 30W PEM fuel cell. This study also proposes the optimum design of a 30W PEM fuel cell. The PEM fuel cell model and hybridization's switching rules are postulated

  5. High drug load, stable, manufacturable and bioavailable fenofibrate formulations in mesoporous silica: a comparison of spray drying versus solvent impregnation methods.

    Science.gov (United States)

    Hong, Shiqi; Shen, Shoucang; Tan, David Cheng Thiam; Ng, Wai Kiong; Liu, Xueming; Chia, Leonard S O; Irwan, Anastasia W; Tan, Reginald; Nowak, Steven A; Marsh, Kennan; Gokhale, Rajeev

    2016-01-01

    Encapsulation of drugs in mesoporous silica using co-spray drying process has been recently explored as potential industrial method. However, the impact of spray drying on manufacturability, physiochemical stability and bioavailability in relation to conventional drug load processes are yet to be fully investigated. Using a 2(3) factorial design, this study aims to investigate the effect of drug-loading process (co-spray drying and solvent impregnation), mesoporous silica pore size (SBA-15, 6.5 nm and MCM-41, 2.5 nm) and percentage drug load (30% w/w and 50% w/w) on material properties, crystallinity, physicochemical stability, release profiles and bioavailability of fenofibrate (FEN) loaded into mesoporous silica. From the scanning electronic microscopy (SEM) images, powder X-ray diffraction and Differential scanning calorimetry measurements, it is indicated that the co-spray drying process was able to load up to 50% (w/w) FEN in amorphous form onto the mesoporous silica as compared to the 30% (w/w) for solvent impregnation. The in vitro dissolution rate of the co-spray dried formulations was also significantly (p = 0.044) better than solvent impregnated formulations at the same drug loading. Six-month accelerated stability test at 40 °C/75 RH in open dish indicated excellent physical and chemical stability of formulations prepared by both methods. The amorphous state of FEN and the enhanced dissolution profiles were well preserved, and very low levels of degradation were detected after storage. The dog data for the three selected co-spray-dried formulations revealed multiple fold increment in FEN bioavailability compared to the reference crystalline FEN. These results validate the viability of co-spray-dried mesoporous silica formulations with high amorphous drug load as potential drug delivery systems for poorly water soluble drugs.

  6. Content of bioactive compounds and antioxidant capacity of pumpkin puree enriched with japanese quince, cornelian cherry, strawberry and apples

    Directory of Open Access Journals (Sweden)

    Agnieszka Nawirska-Olszańska

    2011-03-01

    Full Text Available   Background. When evaluated in terms of taste, smell or active ingredients, pumpkin in itself is not very attractive as a raw material. Hence, it is recommended to blend pumpkin with other fruits, which are aromatic, have a defined taste, and contain a large quantity of active ingredients and organic acids to improve its palatibility. Material and methods. The pumpkin chosen for the experiments was of the variety Karowita, of species Cucurbita maxima. Ten different of compositions were prepared for the purpose of the study: 10, 20 and 30% (w/w of Japanese quince and cornelian cherry each, or 20 and 30% (w/w of strawberry and apple each. The puree was then analysed for dry matter, extract, viscosity, colour, vitamin C, total polyphenols, carotenoids and DPPH. Results. The highest content of vitamin C, which was in direct proportion to the quantity of the supplement added (17.88 to 23.43 mg·100 g-1, was detected in the quince-enriched puree. The lowest vitamin C content was determined in apple-enriched samples (1.36 to 1.6 mg·100 g-1. A similar pattern was observed with total polyphenols: the highest values were measured in quince-enriched puree, and the lowest in the puree supplemented with apple. Conclusion. Taking into account antioxidant properties of the samples, quince-enriched pumpkin puree was found to be the most attractive, and apple-enriched pumpkin puree the least attractive one. The results suggest a wide range of application for pumpkin puree enriched with various additives.  

  7. (Th-U)O2 MOX fuel fabrication and dry recycling of the sintered rejects

    International Nuclear Information System (INIS)

    Thorium is an important nuclear material. Due to its abundance in large quantity in India our preceptors have envisaged three stage nuclear power programme. Thoria based fuel is planned to be used in the third stage of nuclear power programme. (Th-LEU)O2 mixed oxide (MOX) is the proposed fuel for AHWR- LEU-300 in which UO2 content varies from 13 to 30 w%. Fabrication of ThO2-NU fuel of similar composition varying from 13% to 30 % UO2 has been carried out in kg scale at Radiometallurgy Division. Conventional Powder Metallurgical processes like mixing; cold compaction and sintering were employed for fabrication of ThO2-UO2 fuel pellets. Density up to 93-94% TD was achieved in the sintered pellets. XRD result on sintered pellet showed single phase formation. Fuel fabrication process is always associated with generation of green/sintered rejects. Recycling of the sintered reject is important to judiciously utilize the feed material and avoid the accumulation of the waste. As thorium dioxide is a stable compound, recycling of process rejects of thoria based fuels either by dry or wet route is difficult unlike UO2 based fuels. The stable oxidation state of thorium oxide limits oxidative-reductive processing of sinter rejects. Dissolution of thoria fuels in nitric acid is also difficult. The presence of UO2 (13w% to 30w %) in the ThO2-UO2 fuel pellets makes it amenable to oxidative-reductive processing by modifying the fabrication parameters. A process for recycling of the sintered reject has been successfully worked out. This paper discusses the fabrication aspects of Th-NU MOX fuel and dry recycling of process rejects. (author)

  8. CO2 and Nd:YAP laser interaction with lithium disilicate and Zirconia dental ceramics: A preliminary study

    Science.gov (United States)

    Rocca, Jean-Paul; Fornaini, Carlo; Brulat-Bouchard, Nathalie; Bassel Seif, Samy; Darque-Ceretti, Evelyne

    2014-04-01

    Lithium disilicate and Zirconia ceramics offer a high level of accuracy when used in prosthetic dentistry. Their bonding using different resins is highly dependent on micro-mechanical interlocking and adhesive chemical bonding. Investigation of the performances of high strength ceramics when their surface is modified for chemical and mechanical bonding is then required. The aim of this study is to investigate the possibility of using laser for surface treatment of different high strength CAD/CAM ceramics and thus to improve their mechanical and chemical properties. Thirty two CAD/CAM ceramic discs were divided into two different groups: lithium disilicate ceramics (IPS e.max CAD®, Ivoclar, Vivadent, Italy) and Zirconia ceramics (IPS e.max ZirCAD®, Ivoclar, Vivadent, Italy). The Laser surface treatment was performed by Carbon Dioxide laser (Dream Pulse Laser®, Daeshin Enterprise Corp., Korea) at 20 W, 25 W and 30 W CW and by Neodymium Yttrium Aluminum Perovskite laser (Nd:YAP Lokki®, Lobel Medical, France) at 10 W and 30 Hz. Physical modifications of the irradiated ceramic discs were observed by scanning electron microscopy (SEM) and chemically analyzed by Energy-Dispersive Spectroscopy (EDS). Surface wettability was tested using the water drop test and the crystalline structure was investigated using X-ray diffraction (XRD). The macroscopic observation showed a shinier structure in all the groups, while at the SEM observation only CO2 25 W and 30 W treated groups showed cracks and fissures. In the conditions of this study, CO2 laser and Nd:YAP laser with the parameters used create chemical and physical surface modifications of the ceramics, indicating the possibility of an improvement in adhesion of the tested ceramics.

  9. Inorganic ion exchangers based on manganese and potassium for recovery and removal of pollutant metals of aqueous effluents

    International Nuclear Information System (INIS)

    This work presents a study on the synthesis, characterization and ion exchange properties of inorganic ion exchangers based on manganese and potassium. The ion exchangers were synthesized by calcination of the mixture of manganese(II) oxalate and potassium oxalate and were characterized by granulometer distribution analysis, X-ray powder diffraction, infrared spectroscopy and scanning electron microscopic. From the data obtained in characterization it was observed that exist two distinguished groups of these materials. The first group belong to ion exchangers with up to 30% w/w potassium and the second group formed by the ion exchangers with more than 30% w / w of content of potassium in their compositions. The studies of adsorption of these materials showed that the adsorption of Cd2+ is a function of the following parameters as pH, concentration of Cd2+, time of contact between the ion exchangers the concentration of the Cd2+ solution and the interference of other ions like Ni2+. The great pH of adsorption for these materials occur in pH 9, the study of the influence of the cadmium concentration in the adsorption showed that for a group of exchangers the adsorption decreases with the increase of cadmium concentration and for the other group the adsorption increases with the increase of cadmium concentration. The kinetics of adsorption occur in a contact time between the ion exchangers and the Cd2+ solutions relatively short, at about 15 minutes is necessary to establish the equilibrium. The presence of Ni2+ as interfering ion decreases the adsorption of cadmium of 99,7% to 65%. These inorganic ion exchangers showed be good exchangers for Cd2+. (author)

  10. Novos registros de Eunotia Ehrenberg (Eunotiaceae-Bacillariophyta para o Estado do Rio Grande do Sul e Brasil New reports of Eunotia Ehrenberg (Eunotiaceae-Bacillariophyta for Rio Grande do Sul State and Brazil

    Directory of Open Access Journals (Sweden)

    Aline Brugalli Bicca

    2009-06-01

    Full Text Available O trabalho tem como objetivo apresentar as características morfológicas, e/ou estruturais e métricas de 12 espécies de Eunotia (E. batavica A. Berg, E. deficiens Metz., Lange-Bert & García-Rodr., E. genuflexa Nörpel-Sch., E. hepaticola Lang-Bert. & Wydrz., E. herzogii Krasske, E. mucophila (Lange-Bert., Nörpel-Sch. & Alles Lange-Bert., E. pileus Ehr., E. pirla Carter & Flower, E. schwabei Krasske, E. subarcuatoides Alles, Nörpel-Sch. & Lange-Bert., E. transfuga Metz. & Lange-Bert. e E. yanomami Metz. & Lange-Bert. encontradas nas áreas da Lagoa do Casamento e dos Butiazais de Tapes, entre as coordenadas 30º10'-30º40'S e 50º30'-51º30'W, na Planície Costeira do Rio Grande do Sul. São incluídos comentários sobre a distribuição e os ambientes onde os táxons foram encontrados.This paper presents the morphological and/or structural and mensurable characteristics of 12 Eunotia species (E. batavica A. Berg, E. deficiens Metz., Lange-Bert. & García-Rodr., E. genuflexa Nörpel-Sch., E. hepaticola Lang-Bert. & Wydrz., E. herzogii Krasske, E. mucophila (Lange-Bert., Nörpel-Sch. & Alles Lange-Bert., E. pileus Ehr., E. pirla Carter & Flower, E. schwabei Krasske, E. subarcuatoides Alles, Nörpel-Sch. & Lange-Bert., E. transfuga Metz. & Lange-Bert. and E. yanomami Metz. & Lange-Bert. found in the Lagoa do Casamento and Butiazais de Tapes areas, between 30º10'-30º40'S and 50º30'-51º30'W, on the Rio Grande do Sul State Coastal Plain. Comments on distribution and habitats where the taxons are found are included.

  11. Accelerating protein release from microparticles for regenerative medicine applications

    International Nuclear Information System (INIS)

    There is a need to control the spatio-temporal release kinetics of growth factors in order to mitigate current usage of high doses. A novel delivery system, capable of providing both structural support and controlled release kinetics, has been developed from PLGA microparticles. The inclusion of a hydrophilic PLGA–PEG–PLGA triblock copolymer altered release kinetics such that they were decoupled from polymer degradation. A quasi zero order release profile over four weeks was produced using 10% w/w PLGA–PEG–PLGA with 50:50 PLGA whereas complete and sustained release was achieved over ten days using 30% w/w PLGA–PEG–PLGA with 85:15 PLGA and over four days using 30% w/w PLGA–PEG–PLGA with 50:50 PLGA. These three formulations are promising candidates for delivery of growth factors such as BMP-2, PDGF and VEGF. Release profiles were also modified by mixing microparticles of two different formulations providing another route, not previously reported, for controlling release kinetics. This system provides customisable, localised and controlled delivery with adjustable release profiles, which will improve the efficacy and safety of recombinant growth factor delivery. Highlights: ► A new delivery system providing controlled release kinetics has been developed. ► Inclusion of hydrophilic PLGA–PEG–PLGA decoupled release kinetics from degradation. ► Using 10% triblock copolymer produced quasi zero order release over four weeks. ► Mixing microparticle formulations provided another route for controlling release. ► This system provides customisable, localised and controlled delivery of growth factors

  12. Hydroxyapatite scaffolds infiltrated with thermally crosslinked polycaprolactone fumarate and polycaprolactone itaconate.

    Science.gov (United States)

    Sharifi, Shahriar; Shafieyan, Yousef; Mirzadeh, Hamid; Bagheri-Khoulenjani, Shadab; Rabiee, Sayed Mahmood; Imani, Mohammad; Atai, Mohammad; Shokrgozar, Mohammad Ali; Hatampoor, Ali

    2011-08-01

    In this work, two unsaturated derivatives of polycaprolactone (PCL), polycaprolactone fumarate (PCLF), and polycaprolactone itaconate (PCLI), have been synthesized and used as an infiltrating polymer to improve the mechanical properties of brittle hydroxyapatite (HA) scaffolds. PCLF and PCLI were first synthesized through polyesterification of the low molecular weight PCL diols with fumaryl chloride and itaconyl chloride respectively, and then characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, and differential scanning calorimetry analysis. HA scaffolds were sintered using a foam replication technique, with porosity of about 60%. Polymer-HA composites were obtained by infiltrating the HA scaffolds with PCLF and PCLI solution (12.5 and 30 w/v in dichloromethane) followed by thermal crosslinking. The polymer infiltrated HA scaffolds were characterized by scanning electron microscopy, porosimetry, and gravimetrical analysis. The polyesterification reaction of PCL diols with fumarate chloride was more efficient than itaconyl chloride and dependent upon the molecular weight of the initial PCL precursor; the resultant PCLF demonstrated a degree of substitution of 1.2, 4.2, and 2.7 times higher than PCLIs. Polymer infiltration improved the compressive strength of the HA scaffolds, and based upon the type of macromer (PCLF or PCLI) and also their concentration in infiltrating solution (12.5 or 30 w/v %) compressive strength increased about 14-328%. In all studied samples, the reinforcement effect of PCLF infiltration was higher than PCLI. The macromers and their corresponding infiltrated HA scaffolds did not show any significant cytotoxicity toward human primary osteogenic sarcoma cell (G92 cell lines), in vitro. PMID:21626657

  13. Accelerating protein release from microparticles for regenerative medicine applications

    Energy Technology Data Exchange (ETDEWEB)

    White, Lisa J., E-mail: lisa.white@nottingham.ac.uk; Kirby, Giles T.S.; Cox, Helen C.; Qodratnama, Roozbeh; Qutachi, Omar; Rose, Felicity R.A.J.; Shakesheff, Kevin M.

    2013-07-01

    There is a need to control the spatio-temporal release kinetics of growth factors in order to mitigate current usage of high doses. A novel delivery system, capable of providing both structural support and controlled release kinetics, has been developed from PLGA microparticles. The inclusion of a hydrophilic PLGA–PEG–PLGA triblock copolymer altered release kinetics such that they were decoupled from polymer degradation. A quasi zero order release profile over four weeks was produced using 10% w/w PLGA–PEG–PLGA with 50:50 PLGA whereas complete and sustained release was achieved over ten days using 30% w/w PLGA–PEG–PLGA with 85:15 PLGA and over four days using 30% w/w PLGA–PEG–PLGA with 50:50 PLGA. These three formulations are promising candidates for delivery of growth factors such as BMP-2, PDGF and VEGF. Release profiles were also modified by mixing microparticles of two different formulations providing another route, not previously reported, for controlling release kinetics. This system provides customisable, localised and controlled delivery with adjustable release profiles, which will improve the efficacy and safety of recombinant growth factor delivery. Highlights: ► A new delivery system providing controlled release kinetics has been developed. ► Inclusion of hydrophilic PLGA–PEG–PLGA decoupled release kinetics from degradation. ► Using 10% triblock copolymer produced quasi zero order release over four weeks. ► Mixing microparticle formulations provided another route for controlling release. ► This system provides customisable, localised and controlled delivery of growth factors.

  14. Geothermal characteristics of the molasse basin (pilot study - thermal conductivity); Geothermische Eigenschaften des Molassebeckens (Pilotstudie - Waermeleitfaehigkeit)

    Energy Technology Data Exchange (ETDEWEB)

    Leu, W.; Greber, E. [Geoform, Geologische Beratungen und Studien AG, Winterthur (Switzerland); Hopkirk, R.J. [Polydynamics Engineering, Maennedorf (Switzerland); Keller, B. [Mengis und Lorenz AG, Luzern (Switzerland); Rybach, L. [ETH Hoenggerberg, Zuerich (Switzerland). Inst. fuer Geophysik und Radiometrie

    1997-12-01

    Detailed knowledge of the geothermal properties (thermal conductivity and specific heat capacity) of the undergorund becomes more and more important with increasing exploitation of geothermal resources by deep vertical borehole heat exchangers or by seasonal storage installations. For this pilot study all existing thermal conductivity data of the Swiss Molasse were compiled and supplemented with new laboratory measurements on core and cutting samples from deep wells (2.5 to 3.0 W/mK). In a second step top-to-bottom thermal conductivity profiles were calculated from geophysical well logs. These profiles show a clear dependence on lithology and variations in thermal conductivity of up to 1 W/mK over 50-200 m thick intervals. In clay-rich lithofacies thermal conductivity is only slightly dependent on the sedimentary architecture, whereas, in sandy facies obvious distinctions are possible. The modelling of a theoretical 750 m long vertical borehole heat exchanger shows that the potential quality of extractable heat increases or decreases by up to 20% by varying the thermal conductivity with only {+-}0.5 W/mK. (orig.) [Deutsch] Fuer die Nutzung geothermischer Ressourcen mit tiefen Erdwaermesonden und saisonalen Speicheranlagen werden detaillierte Kenntnisse der geothermischen Eigenschaften (Waermeleitfaehigkeit und Waemekapazitaet) des Untergrundes zunehmend wichtig. Im Rahmen dieser Pilotstudie wurden saemtliche verfuegbaren Waermeleitfaehigkeits-Daten von Schweizer Molassegesteinen kompiliert und mit Neumessungen an Kern- und Cuttingsmaterial von Tiefbohrungen ergaenzt (2.5 bis 3.0 W/mK). In einem zweiten Schritt wurden Waermeleitfaehigkeits-Profile mit geophysikalischen Bohr-Logs berechnet. Diese Profile zeigen eine deutliche Abhaengigkeit von der Lithologie mit einer Variation der Waermeleitfaehigkeit von bis zu 1 W/mK ueber 50-200 m maechtige Intervalle. In den tonigen Lithologien kann nur eine schwache Abhaengigkeit der Waermeleitfaehigkeit von der sedimentaeren Architektur beobachtet werden, wogegen in den sandigeren Intervallen eine deutliche Unterscheidung moeglich ist. Die Modellierung einer fiktiven 750 m tiefen Erdwaermesonde zeigt, dass der moegliche Waermeentzug bereits bei Variationen der Waermeleitfaehigkeit von {+-}5 W/mK um bis zu 20% ab- oder zunehmen kann. (orig.)

  15. Comportamento agronômico de bananeira 'Prata-anã' em função do tipo de muda Agromic performance of 'Prata-anã' banana regarding to plant propagation method

    Directory of Open Access Journals (Sweden)

    Luiz Antonio Junqueira Teixeira

    2011-03-01

    Full Text Available Foi realizado um experimento de campo com bananeira 'Prata-anã', visando a avaliar o comportamento agronômico de plantas estabelecidas a partir de três tipos de mudas: convencional, micropropagadas em meio sólido e em meio líquido. A área experimental foi instalada no município de Cristais Paulista-SP (20º23'S; 47º30'W, cujo clima é caracterizado por verão chuvoso e inverno seco. Avaliaram-se o crescimento e a fenologia por meio de medidas periódicas de comprimento e diâmetro do pseudocaule das plantas até a emissão da inflorescência. A incidência de doenças (CMV e mal-do-panamá foi estimada visualmente em função da apresentação de sintomas característicos pelas plantas. As plantas originadas de mudas micropropagadas apresentaram crescimento e desenvolvimento iniciais mais vigorosos, maior precocidade e cachos mais leves do que aquelas estabelecidas com mudas convencionais. Não foram observadas diferenças significativas em relação à incidência de doenças e ao tamanho dos frutos produzidos, em função dos tipos de mudas.A field experiment with 'Prata-anã' banana was conducted to evaluate the agronomic performance of tissue culture-propagated plants in solid or liquid culture medium and conventionally propagated plants. The experiment was installed in Cristais Paulista (20º23'S; 47º30'W, Planalto Region of State of Sao Paulo (Brazil. This region is characterized by a summer rainy season and dry winter. Plant growth and phenology were assessed through periodic measurements of length and stem diameter of the plants until flowering. The incidence of diseases (CMV and Panama disease was estimated visually according to the presentation of symptoms by plants. The tissue culture-propagated-plants in solid or liquid medium showed initial growth and development more vigorous, precocious flowering and lighter bunches than those from conventionally propagated plants. There were no significant differences in the incidence of

  16. Microbial population dynamics in an anaerobic CSTR treating a chemical synthesis-based pharmaceutical wastewater.

    Science.gov (United States)

    Oz, Nilgun Ayman; Ince, Orhan; Ince, Bahar Kasapgil; Akarsubasi, Alper Tunga; Eyice, Ozge

    2003-01-01

    Effects of a chemical synthesis based pharmaceutical wastewater on performance of an anaerobic completely stirred tank reactor (CSTR), activity of acetoclastic methanogens and microbial composition were evaluated under various influent compositions. Initially, the CSTR was fed with glucose up to an organic loading rate (OLR) of 6 kg COD/m3 x d corresponding to an F/M ratio of 0.43 with a hydraulic retention time (HRT) of 2.5 days. A COD removal efficiency of 92% and a methane yield of 0.32 m3 CH4/kg COD(removed) were achieved whilst specific methanogenic activity (SMA) was found to be 336mL CH4/gTVS x d. After the CSTR was fed with pre-aerated wastewater diluted by glucose in different dilution ratios of 10% (w/v), 30% (w/v), 70% (w/v), and 100% (w/v) pre-aerated wastewater, gradual decreases in COD removal efficiency to 71%, methane yield to 0.28 m3CH4/kg COD(removed) and SMA to 166 mL CH4/gTVS d occurred whilst volatile fatty acid concentration reached to 1474 mg/L. After the raw wastewater diluted with the pre-aerated wastewater was fed into the CSTR in increasing ratios of 10% (w/v), 30% (w/v), and 60% (w/v), there was a proportional deterioration in performance in terms of COD removal efficiency, methane yield and acetoclastic methanogenic activity. Epifluorescence microscopy of the seed sludge revealed that Methanococcus-like species, short, and medium rods were found to be equally dominant. The short and medium rod species remained equally dominant groups in the CSTR throughout the feeding regime whilst Methanococcus-like species and long rods were found to be in insignificant numbers at the end of the study. Changes in archael diversity were determined using molecular analyses such as polymerase chain reaction (PCR), and denaturent gradient gel electrophoresis (DGGE). Results showed that overall archeal diversity did not change much whereas changes in composition of eubacterial population occurred.

  17. Utilização de habitats reprodutivos e micro-habitats de vocalização em uma taxocenose de anuros (Amphibia da Mata Atlântica do sudeste do Brasil

    Directory of Open Access Journals (Sweden)

    Jaime Bertoluci

    2002-11-01

    Full Text Available Foi estudada a utilização de sítios reprodutivos e de vocalização em uma taxocenose de anuros do Parque Estadual Intervales, uma reserva de Mata Atlântica localizada no sudeste do Brasil (24°12' - 24°25' S, 48°03' - 48°30' W. Os trabalhos de campo foram desenvolvidos entre abril de 1990 e março de 1991. Na área de estudo, foram registradas 47 espécies pertencentes a quatro famílias: Bufonidae (4, Hylidae (24, Leptodactylidae (18 e Microhylidae (1. Foram obtidos dados sobre a distribuição dos hábitats reprodutivos e dos micro-habitats de vocalização para 26 espécies por meio do monitoramento mensal de seis corpos d'água ao longo de um ciclo anual. O número de espécies que utilizaram um determinado hábitat variou de 7 a 22. As espécies foram classificadas como generalistas ou especialistas. A maioria das espécies mostrou preferência por determinados sítios de vocalização. Para algumas espécies, a especificidade por sítios de vocalização pareceu depender da densidade de machos emitindo canto nupcial e não da composição de espécies das agregações reprodutivas.Breeding and calling site utilization were studied for an anuran community of the Parque Estadual Intervales, an Atlantic Rainforest reserve located in Southeastern Brazil (24°12'-24°25'S, 48°03'-48°30'W. Field work was carried out between April 1990 and March 1991. Forty-seven species from four families were recorded in the study site: Bufonidae (4, Hylidae (24, Leptodactylidae (18, and Microhylidae (1. We were able to obtain data on breeding habitat and microhabitat distribution for 26 species by monitoring six breeding sites year-round on a monthly basis. The number of species in the sites varied from 7 to 22. Species were classified as habitat generalists and specialists based on breeding site utilization. Most species showed preferences for certain calling sites. For some species calling site specificity seemed to depend on the density of the

  18. 采用不同方式的地埋管换热器热响应测试——以中新天津生态城公屋展示中心项目为例%Thermal response test on underground pipe heat exchanger by different ways——taking public housing project exhibition center in Sino-Singapore Tianjin Eco-city as an example

    Institute of Scientific and Technical Information of China (English)

    刘九龙; 陈效文; 姚木生; 唐永香; 袁小飞; 李麟

    2012-01-01

    We use two thermal response test methods (constant heat flux method and temperature method) for ground source heat pump ground heat exchanger pipe test, to test the ground soil thermal parameters. On the basis of over viewing two thermal properties tester principles, characteristics, test methods and data processing methods, we analyzed and compared thermal parameters between two measurings and calculated precisely soil thermal parameters of the construction site. The thermal parameters are basically the same, while hot or cold testing conditions are not very different from the parameters obtained. In the 20℃~30 ℃ emission heat working conditions, heat exchanger for the 120 m double U-type, emission heat quantum is at 25 ~60 W/m. In the 8℃ absorbing hot working conditions, absorbing hot quantum is about 30 W/m. Thermal conductivity is about 1. 5 W/m · ℃ . Thermal diffu-sivity is about 0. 46 × 10 -6m3/s.%利用两种热响应测试方式(恒热流法和恒温法)进行地埋管地源热泵换热试验,测试该地的土壤热物性参数.在概述了两种浅层岩土体热物性原位测试仪的原理、特点、测试方法及数据处理方法的基础上,分析比较了两种方法测量的参数,准确地计算出施工现场土壤的热物性参数.两种测试仪测量的热物性参数基本一致,同时热工况或冷工况试验所取得的参数差别不大.在20℃~ 30℃排热工况条件下,换热器为120 m双U类型时,排热量在25~ 60 W/m,在8℃取热工况条件下,取热量约30 W/m.热导率约1.5 W/m·℃,热扩散率约为0.46×10-6 m3/s.

  19. Adulticidal activity against Stegomyia aegypti (Diptera: Culicidae of three Piper spp. Atividade de três Piper spp. contra adultos de Stegomyia aegypti (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Wej Choochote

    2006-02-01

    Full Text Available Three Piper species, Piper longum, P. ribesoides and P. sarmentosum, were selected for investigation of adulticidal potential against Stegomyia aegypti, a main vector of dengue and dengue haemorrhagic fever. Successive extraction by maceration with 95% ethanol showed percentage yields of ethanolic extracts, which derived from P. longum, P. ribesoides and P. sarmentosum, of 8.89, 3.21 and 5.30% (w/w, respectively. All Piper extracts illustrated an impressive adulticidal activity when tested against female mosquitoes by topical application. The susceptibility of St. aegypti females to ethanol-extracted Piper was dose dependent and varied among the plant species. The highest adulticidal effect was established from P. sarmentosum, followed by P. ribesoides and P. longum, with LD50 values of 0.14, 0.15 and 0.26 µg/female, respectively. The potential of these Piper species, as possible mosquitocides, established convincing activity for further researches to develop natural substances for combat against adult mosquitoes.Três espécies de Piper, Piper longum, P. ribesoides e P. sarmentosum, foram selecionadas para investigação da potencialidade contra Stegomyia aegypti adultos, principal vetor de dengue e febre do dengue hemorrágico. Sucessivas extrações por maceração com etanol a 95% mostraram uma porcentagem de extratos etanólicos, derivados de P. longum, P. ribesoides e P. sarmentosum, de 8,89, 3,21 e 5,30% (w/w, respectivamente. Todos os extratos de Piper mostraram atividade adulticida expressiva quando testados contra fêmeas de mosquitos através de aplicação tópica. A suscetibilidade das fêmeas do St. aegypt ao extrato de Piper etanólico foi dose dependente e variou entre as espécies de plantas. O mais elevado efeito adulticida foi demonstrado a partir do P. sarmentosum, seguido pelo P. ribesoides e P. longum, valores LD50 de 0,14, 0,15 e 0,26 µg/fêmea, respectivamente. O potencial destas espécies de Piper, como poss

  20. AN INVESTIGATION OF THERMAL CHARACTERISTICS OF A SINTERED-WICK HEAT PIPE WITH DOUBLE HEAT SOURCES

    Directory of Open Access Journals (Sweden)

    Nattawut Tharawadee

    2013-01-01

    Full Text Available Heat pipes have been used extensively in the electronic industry for decades especially in laptop computers. For cost-effectiveness, a single heat pipe is designed to simultaneously transfer heat from both the Central Processing Unit (CPU and the Graphics Processing Unit (GPU inside the main board to the heat sink. This causes the efficiency of the heat pipe to change without any theoretical prediction. In this research, thermal performance of a sintered-wick heat pipe with double heat sources has been experimentally and numerically investigated by utilizing the Finite Element Method (FEM. The focus being the effect that the distance between the two heat sources and also the power input pattern (heat source#1 (HT1: heat source#2(HT2 has on temperature and thermal resistance of the heat pipe. The first heat source (HT1 was located at one end and the heat sink was located at another end of the heat pipe, while another heat source (HT2 was placed between HT1 and a heat sink. The ratios of heat input power were controlled at 10W:10W, 20W:10W and 30W:10W. Two copper blocks (15 mm×15 mm were used as heat sources for the evaporator section (Le1, Le2 to electrically supply heat to the bottom half of the heat pipe. A mathematical model using the Finite Element Method (FEM was established to calculate temperature and thermal resistance. The speed of the cooling fan was adjusted to maintain constant operating temperature at the adiabatic section throughout the tests. The operating temperature was controlled at 60 ± 3°C. It was noted that, when distance between the heat sources was increased from 0 mm to 75 mm, thermal resistance slightly decreased from 0.589-0.53°C/W respectively. Heat source 2, therefore, should be placed as close as possible to the condenser section. Both heat sources should have a distance between them of at least 12 mm, which minimizes heat accumulation. When the power input of HT1 was increased from 10 W to 30W (HT2 was

  1. Emergía de tres sistemas agroforestales en el sur del municipio de Lempira, Honduras Emergy of tree agroforestry systems in southern Lempira, Honduras

    Directory of Open Access Journals (Sweden)

    óscar I. Ferreira C.

    2010-07-01

    Full Text Available Se evaluaron el uso de recursos y la sostenibilidad de tres sistemas agroforestales (bosque secundario- BS, tala y quema-TQ y sistema conservacionista Quesungual-SAQ. Se utilizaron datos de 15 parcelas de 200 m² ubicadas entre 14° 05' N y 88° 30' W y transformicidades reportadas en otros estudios. Los mayores valores de emergía se presentaron en la variable Lluvia (1.35E15 sej/ha por año y las mayores diferencias de emergía entre sistemas se observaron en suelo erosionado, especialmente en TQ, BS y SAQ tuvieron mayor Razón de Carga Ambiental que TQ (0.63, 0.14 y 0.02, respectivamente. El sistema TQ presenta el valor más alto del índice de Huella Ecológica seguido por SAQ y BS. El índice de Sostenibilidad de Emergía del sistema TQ fue 34.8, el de SAQ = 135.6 y el de BS = 4123.8, con mayores valores de sostenibilidad en el SAQ y el BS, lo cual indica que son sistemas que favorecen el uso de recursos renovables y locales.Resource use and sustainability of three agroforestry systems (Secondary Woods - BS; Fell and Burn - TQ; and Quesungal Conservation mode - SAQ were evaluated by analyzing data from fifteen 200 m² plots (14° 05' N; 88° 30' W, making use of transformity values reported in other related studies. The highest emergy values were observed for the variable rain (1.35E15 sej/ha per year; and the largest emergy differences were found in eroded soils, especially those of TQ. BS and SAQ exhibited a greater Environmental Load Ratio than TQ (0.63, 0.14 and 0.02, respectively. TQ showed the largest Ecological Footprint Index value, followed by SAQ and BS. Emergy Sustainability Index for TQ was 34.8, whereas SAQ and BS reached respective values of 135.6 and 4,123.8. The latter two data, as compared to the former, reveal how these systems (SAQ and BS favor the use of local renewable resources.

  2. Zoneamento agroecológico para a região de Ribeirão Preto utilizando um sistema de informações geográficas Agroecologic zoning for the Ribeirão Preto Region using a geographic information system

    Directory of Open Access Journals (Sweden)

    Lucieta G. Martorano

    1999-07-01

    Full Text Available Objetivando contribuir com a metodologia de identificação de potencialidades de uso das terras, este trabalho apresenta uma proposta de zoneamento agroecológico da quadrícula de Ribeirão Preto, SP, localizada entre as coordenadas de 21o00'S a 21o30'S e 47o30'W a 48o00'W, com base em características de solo, relevo e clima, utilizando-se de um Sistema de Informações Geográficas. Para caracterizar o regime térmico-hídrico da área utilizou-se os dados de temperatura do ar e de chuva, de 22 localidades, referentes ao período de 1967 a 1996. De acordo com os critérios adotados, quanto a capacidade de uso das terras, o zoneamento identificou seis unidades de utilização da área: agricultura (I; agricultura (II; agricultura (III; pecuária; agrossilvicultura e preservação. As principais conclusões referentes à área de estudo foram: o regime térmico-hídrico é praticamente homogêneo, a vocação dominante é para agricultura (I representando aproximadamente 191.118 hectares, correspondentes a 66,3% da área e cerca de 82,5% das terras possuem vocação para agropecuária e 10,4% devem ser preservadas ou utilizadas seguindo técnicas conservacionistas.In order to contribute with the methodology of identification of land use potentialities, this paper presents a proposal of agroecologic zoning of the quadrangle (21o00'S at 21o30'S and 47o30'W to 48o00'W, of the county of Ribeirão Preto, SP, Brazil, based on soil, relief and climate characteristics, in a GIS environment. Data of air temperature and rainfall of 22 locations from 1967 to 1996 were used to characterize the thermo-hydric regime of the area. Criteria were adopted according to the capacity of land use. The zoning identified six units of land use: agriculture (I; agriculture (II; agriculture (III; cattle; agroforest systems and preservation. It was concluded that the quadrangle has: a relative climatic uniformity; the dominant zone is the agriculture (I; about 82.5% of

  3. Endovenous radiofrequency ablation using stent-type electrode for varicose veins: an experimental study in goats

    Energy Technology Data Exchange (ETDEWEB)

    Won, Je Hwan; Han, Jae Ho; Oh, Chang Kwon [Ajou University Hospital, Suwon (Korea, Republic of); Kwak, Young Lan [Yonsei University College of Medicine, Seoul (Korea, Republic of); Park, Sung Il [Ulsan University GangNeung Asan Hospital, Gangeung (Korea, Republic of)

    2004-10-15

    The purpose of this study was to investigate the feasibility and the optimal conditions of radiofrequency (RF) ablation by using the stent-type electrode upon the saphenous vein of goats for the endovenous treatment of varicose veins. A self-expandable nitinol stent electrode (6 mm diameter, 2 cm length, cell size; 1.3 x 2 mm) was designed to expose the distal 1 cm segment to allow for contact with the venous wall. The proximal part of the electrode was connected to the RF generator by insulated copper wires located within the stent electrode introducer. Initially, to optimize the power setting, ablation of 6 saphenous veins in 3 goats was performed with power settings of 10, 20 and 30 W. Pull back rate of the electrode was 2 and 4 cm/min for each power level, respectively. The goats were sacrificed 4-6 weeks later and histologic examinations of the saphenous veins were done. For the second part of the experiment, RF ablation of 4 saphenous veins from 2 goats was done by applying the optimal power, based upon the first examination; these procedure was performed with variable pull back rates. Again, the goats were sacrificed 1-6 weeks later and histologic examinations were done. Endovenous ablation of the goat saphenous veins at 20 W caused complete obliteration without complication. There was incomplete occlusion at 10 W, and there were vessel perforation, extravasation, and adjacent tissue injury at 30 W. In second part of the study, the complete circumferential obliteration of the vein was demonstrated at a pull back rate of 1 cm/min and 3 cm/min with the power of 20 W. The stent-type electrode may be useful in endovenous RF ablation for treatment of varicose veins. For stents with a diameter of 6 mm, the optional combination of 20 W of power with a pull back rate of 1-3 cm/min produced the most favorable results. Further study and clinical investigations are warranted.

  4. Photodynamic therapy for basal cell skin cancer ENT-organs

    Directory of Open Access Journals (Sweden)

    V. N. Volgin

    2014-01-01

    Full Text Available Results of photodynamic therapy in 96 patients with primary and recurrent basal cell skin cancer of ENT-organs are represented. For photodynamic therapy the Russian-made photosensitizer Photoditazine at dose of 0.6–1.4 mg/kg was used. Parameters were selected taking into account type and extent of tumor and were as follows: output power – 0.1–3.0 W, power density – 0.1–1.3 W/cm2, light dose – 100–400 J/cm2. The studies showed high efficacy of treatment for primary and recurrent basal cell skin cancer of nose, ear and external auditory canal – from 87.5 to 94.7% of complete regression. Examples of efficacy of the method are represented in the article. High efficacy and good cosmetic effects allowed to make a conclusion about perspectivity of photodynamic therapy for recurrent basal cell skin cancer of ENT-organs. 

  5. Alternating magnetic field energy absorption in the dispersion of iron oxide nanoparticles in a viscous medium

    Science.gov (United States)

    Smolkova, Ilona S.; Kazantseva, Natalia E.; Babayan, Vladimir; Smolka, Petr; Parmar, Harshida; Vilcakova, Jarmila; Schneeweiss, Oldrich; Pizurova, Nadezda

    2015-01-01

    Magnetic iron oxide nanoparticles were obtained by a coprecipitation method in a controlled growth process leading to the formation of uniform highly crystalline nanoparticles with average size of 13 nm, which corresponds to the superparamagnetic state. Nanoparticles obtained are a mixture of single-phase nanoparticles of magnetite and maghemite as well as nanoparticles of non-stoichiometric magnetite. The subsequent annealing of nanoparticles at 300 °C in air during 6 h leads to the full transformation to maghemite. It results in reduced value of the saturation magnetization (from 56 emu g-1 to 48 emu g-1) but does not affect the heating ability of nanoparticles. A 2-7 wt% dispersion of as-prepared and annealed nanoparticles in glycerol provides high heating rate in alternating magnetic fields allowed for application in magnetic hyperthermia; however the value of specific loss power does not exceed 30 W g-1. This feature of heat output is explained by the combined effect of magnetic interparticle interactions and the properties of the carrier medium. Nanoparticles coalesce during the synthesis and form aggregates showing ferromagnetic-like behavior with magnetization hysteresis, distinct sextets on Mössbauer spectrum, blocking temperature well about room temperature, which accounts for the higher energy barrier for magnetization reversal. At the same time, low specific heat capacity of glycerol intensifies heat transfer in the magnetic dispersion. However, high viscosity of glycerol limits the specific loss power value, since predominantly the Neel relaxation accounts for the absorption of AC magnetic field energy.

  6. Preozonation of primary-treated municipal wastewater for reuse in biofuel feedstock generation

    Energy Technology Data Exchange (ETDEWEB)

    Mondala, Andro H.; Hernandez, Rafael; French, W. Todd; Estévez, L. Antonio; Meckes, Mark; Trillo, Marlene; Hall, Jacqueline

    2010-11-09

    The results of a laboratory scale investigation on ozone pretreatment of primary-treated municipal wastewater for potential reuse in fermentation processes for the production of biofuels and bio-based feedstock chemicals were presented. Semi-batch preozonation with 3.0% (w/w) ozone at 1 L min -1 resulted into a considerable inactivation of the indigenous heterotrophic bacteria in the wastewater with less than 0.0002% comprising the ozone-resistant fraction of the microbial population. The disinfection process was modeled using first-order inactivation kinetics with a rate constant of 4.39 10 -3 s -1. Chemical oxygen demand (COD) levels were reduced by 30% in 1-h experiments. COD depletion was also modeled using a pseudo-first-order kinetics at a rate constant of 9.50 10 -5 s -1. Biological oxygen demand (BOD 5) values were reduced by 60% up to 20 min of ozonation followed by a plateau and some slight increases attributed to partial oxidation of recalcitrant materials. Ozone also had no substantial effect on the concentration of ammonium and phosphate ions, which are essential for microbial growth and metabolism. Preliminary tests indicated that oleaginous microorganisms could be cultivated in the ozonated wastewater, resulting in relatively higher cell densities than in raw wastewater and comparable results with autoclave-sterilized wastewater. This process could potentially produce significant quantities of oil for biofuel production from municipal wastewater streams.

  7. Effect of Medicago sativa L. and compost on organic and inorganic pollutant removal from a mixed contaminated soil and risk assessment using ecotoxicological tests.

    Science.gov (United States)

    Marchand, Charlotte; Hogland, William; Kaczala, Fabio; Jani, Yahya; Marchand, Lilian; Augustsson, Anna; Hijri, Mohamed

    2016-11-01

    Several Gentle Remediation Options (GRO), e.g., plant-based options (phytoremediation), singly and combined with soil amendments, can be simultaneously efficient for degrading organic pollutants and either stabilizing or extracting trace elements (TEs). Here, a 5-month greenhouse trial was performed to test the efficiency of Medicago sativa L., singly and combined with a compost addition (30% w/w), to treat soils contaminated by petroleum hydrocarbons (PHC), Co and Pb collected at an auto scrap yard. After 5 months, total soil Pb significantly decreased in the compost-amended soil planted with M. sativa, but not total soil Co. Compost incorporation into the soil promoted PHC degradation, M. sativa growth and survival, and shoot Pb concentrations [3.8 mg kg(-1) dry weight (DW)]. Residual risk assessment after the phytoremediation trial showed a positive effect of compost amendment on plant growth and earthworm development. The O2 uptake by soil microorganisms was lower in the compost-amended soil, suggesting a decrease in microbial activity. This study underlined the benefits of the phytoremediation option based on M. sativa cultivation and compost amendment for remediating PHC- and Pb-contaminated soils. PMID:27216854

  8. Natural bioactive compounds from winery by-products as health promoters: a review.

    Science.gov (United States)

    Teixeira, Ana; Baenas, Nieves; Dominguez-Perles, Raul; Barros, Ana; Rosa, Eduardo; Moreno, Diego A; Garcia-Viguera, Cristina

    2014-01-01

    The relevance of food composition for human health has increased consumers' interest in the consumption of fruits and vegetables, as well as foods enriched in bioactive compounds and nutraceuticals. This fact has led to a growing attention of suppliers on reuse of agro-industrial wastes rich in healthy plant ingredients. On this matter, grape has been pointed out as a rich source of bioactive compounds. Currently, up to 210 million tons of grapes (Vitis vinifera L.) are produced annually, being the 15% of the produced grapes addressed to the wine-making industry. This socio-economic activity generates a large amount of solid waste (up to 30%, w/w of the material used). Winery wastes include biodegradable solids namely stems, skins, and seeds. Bioactive compounds from winery by-products have disclosed interesting health promoting activities both in vitro and in vivo. This is a comprehensive review on the phytochemicals present in winery by-products, extraction techniques, industrial uses, and biological activities demonstrated by their bioactive compounds concerning potential for human health. PMID:25192288

  9. Phospholipon 90H (P90H)-based PEGylated microscopic lipospheres delivery system for gentamicin:an antibiotic evaluation

    Institute of Scientific and Technical Information of China (English)

    Mumuni Audu Momoh; Charles Okechukwu Esimone

    2012-01-01

    Objective: To formulate gentamicin liposphere by solvent-melting method using lipids and polyethylene glycol 4 000 (PEG-4 000) for oral administration. Methods: Gentamicin lipospheres were prepared by melt-emulsification using 30% w/w Phospholipon® 90H in Beeswax as the lipid matrix containing PEG-4 000. These lipospheres were characterized by evaluating on encapsulation efficiency, loading capacity, change in pH and the release profile. Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Salmonella paratyphii and Staphylococcus aureus using the agar diffusion method. Results:Photomicrographs revealed spherical particles within a micrometer range with minimal growth after 1 month. The release of gentamicin in vitro varied widely with the PEG-4 000 contents. Moreover, significant (P>0.05) amount of gentamicin was released in vivo from the formulation. The encapsulation and loading capacity were all high, indicating the ability of the lipids to take up the drug. The antimicrobial activities were very high especially against Pseudomonas compare to other test organisms. This strongly suggested that the formulation retain its bioactive characteristics. Conclusions: This study strongly suggest that the issue of gentamicin stability and poor absorption in oral formulation could be adequately addressed by tactical engineering of lipid drug delivery systems such as lipospheres.

  10. Measurement of Deeply Virtual Compton Scattering and its t-dependence at HERA

    CERN Document Server

    Aaron, F D; Alexa, C; Andreev, V; Antunovic, B; Aplin, S; Asmone, A; Astvatsatourov, A; Backovic, S; Baghdasaryan, A; Baranov, P; Barrelet, E; Bartel, Wulfrin; Baudrand, S; Beckingham, M; Begzsuren, K; Behnke, O; Behrendt, O; Belousov, A; Berger, N; Bizot, J C; Boenig, M O; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Bruncko, D; Büsser, F W; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cozzika, G; Cvach, J; Dainton, J B; Daum, K; Deák, M; De Boer, Y; Delcourt, B; Del Degan, M; Delvax, J; de Roeck, A; De Wolf, E A; Diaconu, C; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Eliseev, A; Elsen, E; Essenov, S; Falkiewicz, A; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Finke, L; Fleischer, M; Fomenko, A; Franke, G; Frisson, T; Gabathuler, E; Gayler, J; Ghazaryan, S; Glazov, A; Glushkov, I; Görlich, L; Goettlich, M; Gogitidze, N; Gorbounov, S; Gouzevitch, M; Grab, C; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Hansson, M; Heinzelmann, G; Helebrant, C; Henderson, R C W; Henschel, H; Herrera-Corral, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hovhannisyan, A; Hreus, T; Jacquet, M; Janssen, M E; Janssen, X; Jemanov, V; Jönsson, L B; Johnson, D P; Jung, A W; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Klimkovich, T; Kluge, T; Knutsson, A; Kogler, R; Korbel, V; Kostka, P; Krämer, M; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Krüger, K; Kutak, K; Landon, M P J; Lange, W; Lastoviicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Li, G; Lindfeld, L; Lipka, K; Liptaj, A; List, B; List, J; Loktionova, N; López-Fernandez, R; Lubimov, V; Lucaci-Timoce, A I; Lytkin, L; Makankine, A; Malinovskii, E I; Marage, P; Marti, L; Martyn, H U; Maxfield, S J; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Mohamed, A; Moreau, F; Morozov, A; Morris, J V; Mozer, M U; Mudrinic, M; Müller, K; Murn, P; Nankov, K; Naroska, B; Naumann, T; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nowak, K; Nozicka, M; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, T; Pascaud, C; Patel, G D; Peng, H; Pérez, E; Perez-Astudillo, D; Perieanu, A; Petrukhin, A; Picuric, I; Piec, S; Pitzl, D; Placakyte, R; Polifka, R; Povh, B; Preda, T; Prideaux, P; Radescu, V; Rahmat, A J; Raicevic, N; Raspiareza, A; Ravdandorj, T; Reimer, P; Risler, C; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rurikova, Z; Rusakov, S; Salek, D; Salvaire, F; Sankey, D P C; Sauter, M; Sauvan, E; Schmidt, S; Schmitt, S; Schmitz, C; Schoeffel, L; Schöning, A; Schultz-Coulon, H C; Sefkow, F; Shaw-West, R N; Shevyakov, I; Shtarkov, L N; Sloan, T; Smiljanic, I; Smirnov, P; Soloviev, Yu; South, D; Spaskov, V; Specka, A; Staykova, Z; Steder, M; Stella, B; Stiewe, J; Straumann, U; Sunar, D; Sykora, T; Tchoulakov, V; Thompson, G; Thompson, P D; Toll, T; Tomasz, F; Tran, T H; Traynor, D; Trinh, T N; Truöl, P; Tsakov, I; Tseepeldorj, B; Tsurin, I; Turnau, J; Tzamariudaki, E; Urban, K; Valkárová, A; Vallée, C; Van Mechelen, P; Vargas, A; Trevino; Vazdik, Ya; Vinokurova, S; Volchinski, V; Weber, G; Weber, R; Wegener, D; Werner, C; Wessels, M; Wissing, C; Wolf, R; Wünsch, E; Yeganov, V; Zácek, J; Zaleisak, J; Zhang, Z; Zhelezov, A; Zhokin, A; Zhu, Y C; Zimmermann, T; Zohrabyan, H; Zomer, F

    2008-01-01

    A measurement of elastic deeply virtual Compton scattering gamma* p -> gamma p using e-p collision data recorded with the H1 detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 145 pb^-1. The cross section is measured as a function of the virtuality Q^2 of the exchanged photon and the centre-of-mass energy W of the gamma*p system in the kinematic domain 6.5 < Q^2 < 80 GeV^2, 30 < W < 140 GeV and |t| < 1 GeV^2, where t denotes the squared momentum transfer at the proton vertex. The cross section is determined differentially in t for different Q^2 and W values and exponential t-slope parameters are derived. The measurements are compared to a NLO QCD calculation based on generalised parton distributions. In the context of the dipole approach, the geometric scaling property of the DVCS cross section is studied for different values of t.

  11. The Effect of Seasonal Variation and Angle of Inclination on the Performances of Photovoltaic Panels in South Eastern Nigeria

    Directory of Open Access Journals (Sweden)

    N.V. Ogueke

    2013-01-01

    Full Text Available The effects of seasonal variation and angle of inclination on the performances of photovoltaic panels in south eastern Nigeria are presented. Three photovoltaic panels, each with a rated capacity of 60 W, were used for the study in each of the locations considered. Three installation positions considered are: horizontal, an angle equal to the local latitude of location and an angle 5º greater than the local latitude of location. Power output from these panels was measured at fixed time interval from dawn to dusk for 12 months. Results obtained show an average performance of 25-30 W representing about 42-50% of the panels rated capacity. Furthermore, the horizontally installed panels, on the average, presented better performance than the others angles. Thus utilization of photovoltaic panels for power generation in the region considered should be limited to lighting applications and applications within the same power requirement range. Also for overall best performance, they should be installed in a horizontal position.

  12. Application of Capmul MCM and caprylic acid for the development of danazol-loaded SEDDS.

    Science.gov (United States)

    Li, Suhua; Madan, Parshotam; Lin, Senshang

    2014-07-25

    Abstract The feasibility of using Capmul MCM and caprylic acid (medium-chain triglyceride pre-digestion products) as the lipid phase was investigated for the development of self-emulsifying drug delivery system (SEDDS) as a carrier system to enhance solubilization of poorly water-soluble danazol. The composition of SEDDS was first evaluated by phase diagrams of lipid/surfactant/water systems. Thereafter, danazol-loaded SEDDS was formulated and subjected to dispersion/precipitation study in distilled water, HCl buffer, phosphate buffer, or biorelevant aqueous media. The mechanism of danazol dispersion was investigated by comparing the solubilization capacity of blank SEDDS dispersed in various aqueous media with respective dispersion/precipitation profiles obtained. Phase diagrams showed that at least 30% (w/w) Cremophor RH40, as the surfactant, was needed to properly emulsify Capmul MCM:caprylic acid (1:1), as the lipid phase. Different extent of danazol precipitation was observed upon the dispersion of danazol-loaded SEDDS in different aqueous media. Danazol precipitation was dominated by the solubilization capacity of danazol, which was influenced by the ratio of Capmul MCM:CA and Cremophor RH40, pH of aqueous media, gastrointestinal composition, and blank SEDDS concentration. PMID:25059382

  13. Copper(II) complexes with highly water-soluble L- and D-proline-thiosemicarbazone conjugates as potential inhibitors of Topoisomerase IIα.

    Science.gov (United States)

    Bacher, Felix; Enyedy, Éva A; Nagy, Nóra V; Rockenbauer, Antal; Bognár, Gabriella M; Trondl, Robert; Novak, Maria S; Klapproth, Erik; Kiss, Tamás; Arion, Vladimir B

    2013-08-01

    Two proline-thiosemicarbazone bioconjugates with excellent aqueous solubility, namely, 3-methyl-(S)-pyrrolidine-2-carboxylate-2-formylpyridine thiosemicarbazone [L-Pro-FTSC or (S)-H2L] and 3-methyl-(R)-pyrrolidine-2-carboxylate-2-formylpyridine thiosemicarbazone [D-Pro-FTSC or (R)-H2L], have been synthesized and characterized by elemental analysis, one- and two-dimensional (1)H and (13)C NMR spectroscopy, and electrospray ionization mass spectrometry. The complexation behavior of L-Pro-FTSC with copper(II) in an aqueous solution and in a 30% (w/w) dimethyl sulfoxide/water mixture has been studied via pH potentiometry, UV-vis spectrophotometry, electron paramagnetic resonance, (1)H NMR spectroscopy, and spectrofluorimetry. By the reaction of copper(II) acetate with (S)-H2L and (R)-H2L in water, the complexes [Cu(S,R)-L] and [Cu(R,S)-L] have been synthesized and comprehensively characterized. An X-ray diffraction study of [Cu(S,R)-L] showed the formation of a square-pyramidal complex, with the bioconjugate acting as a pentadentate ligand. Both copper(II) complexes displayed antiproliferative activity in CH1 ovarian carcinoma cells and inhibited Topoisomerase IIα activity in a DNA plasmid relaxation assay. PMID:23829568

  14. 龙须菜体表附生细菌的几种分离方法比较%Comparison with Several Methods to Isolate Epiphytic Bacteria from Gracilaria lemaneiformis (Rhodophyta)

    Institute of Scientific and Technical Information of China (English)

    徐永健; 乐观宗; 张友平

    2007-01-01

    采用超声波粉碎法、涡旋振荡法、超声波清洗法、研磨匀浆法等4种不同的方法处理龙须菜,分离其体表的附生细菌,并对分离细菌的数量、种类、形态结构、细胞壁特性等进行了观察和分析.通过对不同方法和相同方法的不同处理所得结果比较显示,超声波清洗法和研磨匀浆法对分离细菌的数量和种类效果都较差;超声波粉碎法和涡旋振荡法效果较好,尤以超声波粉碎法的30W30s处理效果最好,该方法分离到本项目4个方法13个处理获得的16个菌株中的12个菌株,龙须菜的细菌数1.75×106cells/g.

  15. Enhancement of monacolin K production via intergeneric protoplast fusion between Aspergillus terreus and Monascus anka

    Institute of Scientific and Technical Information of China (English)

    Chen Zhi; Lin Wen; Yu Ping; Song Yuan

    2007-01-01

    Intergenric protoplast fusion between Aspergillus terreus CA99 and Monascus anka M-3, the high and low producers of monacolin K respectively, was performed for enhancement of monacolin K production. The 24-hour-old mycelia of A. terreus CA99 and M. anka M-3 were treated with 0.5 % lywallzyme, 0.3 % snailase and 0.3 % cellulase at 34 ℃ for 5 h and at 30 ℃ for 3.5 h, and their protoplasts formation reached 1.76 × 107/mL and 1.68 × 107/mL respectively. Parental protoplasts were irradiated with a 30 W UVlight away from 30 cm for 3 min and then mixed. The mixture was incubated with 30% PEG 6000 for 15 min. The reviving fusants were isolated on the regeneration plates. Of the 363 fusants isolated, over 100 showed enhanced monacolin K production compared with the parental strain M. anka M-3. Ten of them produced monacolin K about 1.6-fold of that M. anka M-3 does and the monacolin K titer of two fusants (F49 and F104) increased by about 1-fold. The monacolin K yields of F49 and F104 were 460 μg/mL and 457 μg/mL respectively. In optimized fermentation medium, the monacolin K titer of F49 reached 1216 μg/mL.

  16. An integrated method incorporating sulfur-oxidizing bacteria and electrokinetics to enhance removal of copper from contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Maini, G.; Sharman, A.K.; Sunderland, G.; Knowles, C.J.; Jackman, S.A.

    2000-03-15

    The combination of bioleaching and electrokinetics for the remediation of metal contaminated land has been investigated. In bioleaching, bacteria convert reduced sulfur compounds to sulfuric acid, acidifying soil and mobilizing metal ions. In electrokinetics, DC current acidifies soil, and mobilized metals are transported to the cathode by electromigration. When bioleaching was applied to silt soil artificially contaminated with seven metals and amended with sulfur, bacterial activity was partially inhibited and limited acidification occurred. Electrokinetic treatment of silt soil contaminated solely with 1000 mg/kg copper nitrate showed 89% removal of copper from the soil within 15 days. To combine bioleaching and electrokinetics sequentially, preliminary partial acidification was performed by amending copper-contaminated soil with sulfur (to 5% w/w) and incubating at constant moisture (30% w/w) and temperature (20 C) for 90 days. Indigenous sulfur oxidizing bacteria partially acidified the soil from pH 8.1 to 5.4. This soil was then treated by electrokinetics yielding 86% copper removal in 16 days. In the combined process, electrokinetics stimulated sulfur oxidation, by removing inhibitory factors, yielding a 5.1-fold increase in soil sulfate concentration. Preacidification by sulfur-oxidizing bacteria increased the cost-effectiveness of the electrokinetic treatment by reducing the power requirement by 66%.

  17. Isolation and characterization of soluble sulfated polysaccharide from the red seaweed Glucaric cornea

    International Nuclear Information System (INIS)

    The composition, structure and rheological properties of soluble sulphated polysaccharide Glucaric cornea from Brazilian red seaweeds were investigated. The main components of polysaccharide were 3,6-anhydrogalactose (24.7%) and galactose (64.6%). In addition, minor components as 6-O-methyl-galactose (8.5%), glucose (1.5%), xylose (0.7%) and sulfated groups (4.8%) were detected. Comparison between sulphates content determined by Ft-IR spectroscopy and micro elemental analysis was made. Data from 13C NMR and FT-IR provided evidence of sulphation in C-4 and C-6 of galactose. No gelation with 1.5, 2.0 and 3.0 % (w/v) aqueous solution was observed, even cooled up to 4 deg C. GPC indicated two majors polysaccharide fractions of Mpk 7.4 x 104 and 1.8 x 104 g/mol and a minor fraction of Mpk 2.1 x 106 g/mol. (author)

  18. Stability of β-carotene in protein-stabilized oil-in-water delivery systems.

    Science.gov (United States)

    Cornacchia, Leonardo; Roos, Yrjo H

    2011-07-13

    Inclusion of liposoluble bioactive compounds in fortified foods represents a complex challenge due to the labile nature of such compounds and the instability of oil-in-water emulsion-based delivery systems. In the present study, dispersions prepared with 10% (w/w) sunflower oil (SO) or hydrogenated palm kernel oil (HPKO) containing 0.05% (w/w) β-carotene were stabilized by various concentrations of whey protein isolate (WPI) or sodium caseinate (NaCas) (0.1 to 2.0% w/w) in 30% (w/w) sucrose aqueous solutions. Physicochemical characterization of emulsions was done considering the particle size, the particle surface protein coverage, and the physical state of continuous and dispersed phases. Physical stability of the systems and their protection properties on β-carotene were compared. The lipid carrier type and interfacial structure were investigated as the two key factors which regulate the stability of labile lipophilic bioactive molecules in food model systems. Our results showed high β-carotene stability when O/W systems were stable (protein concentration ≥0.8% w/w.) A (partially) solid lipid carrier (HPKO) enhanced protection compared to the liquid carrier (SO) as the bioactive molecules were entrapped in isolated domains within the solid lattice and kept apart from reactive species in the surroundings. NaCas provided a better barrier than WPI due to the different amino acid composition and interface structure which significantly reduced β-carotene degradation rate.

  19. Selective removal of dental composite with a diode-pumped Er:YAG laser

    Science.gov (United States)

    Fried, William A.; Chan, Kenneth H.; Darling, Cynthia L.; Fried, Daniel

    2016-02-01

    Selective removal of dental composite with high precision is best accomplished using lasers operating at high pulse repetition rates focused to a small spot size. Conventional flash-lamp pumped Er:YAG lasers are poorly suited for this purpose, but new diode-pumped Er:YAG lasers have become available operating at high pulse repetition rates. The purpose of this study was to compare the ablation rates and selectivity of enamel and composite for a 30 W diode-pumped Er:YAG laser operating with a pulse duration of 30-50-μs and evaluate it's suitability for the selective removal of composite from tooth surfaces. The depth of ablation and changes in surface morphology were assessed using digital microscopy. The fluence range of 30-50 J/cm2 appeared optimal for the removal of composite, and damage to sound enamel was limited to less than 100-μm after the removal of composite as thick as 700-800-μm. Future studies will focus on the use of methods of feedback to further increase selectivity.

  20. Recrystallization characteristics of high hydrostatic pressure gelatinized normal and waxy corn starch.

    Science.gov (United States)

    Li, Wenhao; Tian, Xiaoling; Wang, Peng; Saleh, Ahmed S M; Luo, Qingui; Zheng, Jianmei; Ouyang, Shaohui; Zhang, Guoquan

    2016-02-01

    High hydrostatic pressure (HHP) can lead to starch gelatinization at room temperature, while the retrogradation mechanism of HHP gelatinized starch is not well known. HHP gelatinized normal and waxy corn starches were stored at room temperature for 192 h in order to investigate the retrogradation characteristics. The scanning electron microscopy (SEM), polarised light microscopy and differential scanning calorimetric (DSC) analysis showed that the pressurization of normal and waxy corn starch suspensions with concentration of 30% (w/v) at 600 MPa for 15 min resulted in a complete gelatinization. In addition, the pressure-gelatinized normal and waxy corn starch gels were stored and subjected to X-ray diffraction (XRD) analysis, resistant starch content determination, swelling power and pasting behavior. The retrograded normal maize and waxy maize starch showed a substantial loss of A-type crystallinity. Both pressure-gelatinized normal and waxy corn starches showed an increase in resistant starch content and relative crystallinity degree with the increase of storage time. In addition, restricted starch swelling power and lower pasting viscosities were observed for these two retrograded starches. The amylose molecule within starch granules has been regarded as the main factor to affect the structural and physicochemical properties during the retrogradation process of HHP-gelatinized starch granules.

  1. Resistant Starch Contents of Native and Heat-Moisture Treated Jackfruit Seed Starch

    Directory of Open Access Journals (Sweden)

    Ornanong S. Kittipongpatana

    2015-01-01

    Full Text Available Native jackfruit seed starch (JFS contains 30% w/w type II resistant starch (RS2 and can potentially be developed as a new commercial source of RS for food and pharmaceutical application. Heat-moisture treatment (HMT was explored as a mean to increase RS content of native JFS. The effect of the conditions was tested at varied moisture contents (MC, temperatures, and times. Moisture levels of 20–25%, together with temperatures 80–110°C, generally resulted in increases of RS amount. The highest amount of RS (52.2% was achieved under treatment conditions of 25% MC and 80°C, for 16 h (JF-25-80-16. FT-IR peak ratio at 1047/1022 cm−1 suggested increases in ordered structure in several HMT-JFS samples with increased RS. SEM showed no significant change in the granule appearance, except at high moisture/temperature treatment. XRD revealed no significant change in peaks intensities, suggesting the crystallinity within the granule was mostly retained. DSC showed increases in Tg and, in most cases, ΔT, as the MC was increased in the samples. Slight but significant decreases in ΔH were observed in samples with low RS, indicating that a combination of high moisture and temperature might cause partial gelatinization. HMT-JFS with higher RS exhibited less swelling, while the solubility remained mostly unchanged.

  2. Resistant starch contents of native and heat-moisture treated jackfruit seed starch.

    Science.gov (United States)

    Kittipongpatana, Ornanong S; Kittipongpatana, Nisit

    2015-01-01

    Native jackfruit seed starch (JFS) contains 30% w/w type II resistant starch (RS2) and can potentially be developed as a new commercial source of RS for food and pharmaceutical application. Heat-moisture treatment (HMT) was explored as a mean to increase RS content of native JFS. The effect of the conditions was tested at varied moisture contents (MC), temperatures, and times. Moisture levels of 20-25%, together with temperatures 80-110°C, generally resulted in increases of RS amount. The highest amount of RS (52.2%) was achieved under treatment conditions of 25% MC and 80°C, for 16 h (JF-25-80-16). FT-IR peak ratio at 1047/1022 cm(-1) suggested increases in ordered structure in several HMT-JFS samples with increased RS. SEM showed no significant change in the granule appearance, except at high moisture/temperature treatment. XRD revealed no significant change in peaks intensities, suggesting the crystallinity within the granule was mostly retained. DSC showed increases in T g and, in most cases, ΔT, as the MC was increased in the samples. Slight but significant decreases in ΔH were observed in samples with low RS, indicating that a combination of high moisture and temperature might cause partial gelatinization. HMT-JFS with higher RS exhibited less swelling, while the solubility remained mostly unchanged.

  3. High-surface-quality nanocrystalline InN layers deposited on GaN templates by RF sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Valdueza-Felip, Sirona; Naranjo, Fernando B.; Gonzalez-Herraez, Miguel [Grupo de Ingenieria Fotonica, Departamento de Electronica, Escuela Politecnica Superior, Universidad de Alcala, Campus Universitario, 28871 Alcala de Henares, Madrid (Spain); Lahourcade, Lise; Monroy, Eva [Equipe mixte CEA-CNRS-UJF, Nanophysique et Semiconducteurs, INAC/SP2M/PSC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Fernandez, Susana [Departamento de Energias Renovables, Energia Solar Fotovoltaica, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense 22, 28040 Madrid (Spain)

    2011-01-15

    We report a detailed study of the effect of deposition parameters on optical, structural, and morphological properties of InN films grown by reactive radio-frequency (RF) sputtering on GaN-on-sapphire templates in a pure nitrogen atmosphere. Deposition parameters under study are substrate temperature, RF power, and sputtering pressure. Wurtzite crystallographic structure with c-axis preferred growth orientation is confirmed by X-ray diffraction measurements. For the optimized deposition conditions, namely at a substrate temperature of 450 C and RF power of 30 W, InN films present a root-mean-square surface roughness as low as {proportional_to}0.4 nm, comparable to the underlying substrate. The apparent optical bandgap is estimated at 720 nm (1.7 eV) in all cases. However, the InN absorption band tail is strongly influenced by the sputtering pressure due to a change in the species of the plasma. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Optimization of the Dilute Acid Hydrolyzator for Cellulose-to-Bioethanol Saccharification

    Directory of Open Access Journals (Sweden)

    Theocharis Tsoutsos

    2011-10-01

    Full Text Available The production of fermentable sugar solutions for bioethanol production is optimized. The process of acid hydrolysis using dilute H2SO4 was selected. Suitable lignocellulosics which are abundant in the Mediterranean (corn stover, hardwood and wheat straw were investigated, and therefore their exploitation could be economically feasible. The process was studied in the two most common hydrolyzators (batch and continuous stirred by developing a specific simulator for different raw materials. The simulation was applied in a wide range of temperatures (100–240 °C and acid concentrations (0.5–3.0% w/w, in order to optimize the productivity of fermentable pentosans and hexosans. It was confirmed that the production of sugar-rich solutions required a two-stage process; in the first stage the degradation of sugars takes place, since pentoses are formulated under milder conditions than hexoses; in the second stage of simulation, a variety of samples with high sugar concentration and low degradation products are tested. The xylose productivity ranges between 85–95% under the most optimal conditions compared to the theoretical values, while large variations in glucose were frequent (10–55% in comparison with the theoretical values. The best theoretical results were achieved for wheat straw hydrolysis in a batch reactor.

  5. Simultaneous saccharification and high titer lactic acid fermentation of corn stover using a newly isolated lactic acid bacterium Pediococcus acidilactici DQ2.

    Science.gov (United States)

    Zhao, Kai; Qiao, Qingan; Chu, Deqiang; Gu, Hanqi; Dao, Thai Ha; Zhang, Jian; Bao, Jie

    2013-05-01

    A lactic acid bacterium with high tolerance of temperature and lignocellulose derived inhibitor was isolated and characterized as Pediococcus acidilactici DQ2. The strain used in the simultaneous saccharification and fermentation (SSF) for high titer lactic acid production at the high solids loading of corn stover. Corn stover was pretreated using the dry sulphuric acid pretreatment, followed by a biological detoxification to remove the inhibitors produced in the pretreatment. The bioreactor with a novel helical impeller was used to the SSF operation of the pretreated and biodetoxified corn stover. The results show that a typical SSF operation at 48 °C, pH 5.5, and near 30% (w/w) solids loading in both 5 and 50 L bioreactors was demonstrated. The lactic acid titer, yield, and productivity reached 101.9 g/L, 77.2%, and 1.06 g/L/h, respectively. The result provided a practical process option for cellulosic lactic acid production using virgin agriculture lignocellulose residues.

  6. Optimization of alkaline and dilute acid pretreatment of agave bagasse by response surface methodology

    Directory of Open Access Journals (Sweden)

    Abimael I. Ávila-Lara

    2015-09-01

    Full Text Available Utilization of lignocellulosic materials for the production of value-added chemicals or biofuels generally requires a pretreatment process to overcome the recalcitrance of the plant biomass for further enzymatic hydrolysis and fermentation stages. Two of the most employed pretreatment processes are the ones that used dilute acid (DA and alkaline (AL catalyst providing specific effects on the physicochemical structure of the biomass such as high xylan and lignin removal for DA and AL, respectively. Another important effect that need to be studied is the use of a high solids pretreatment (≥15% since offers many advantaged over lower solids loadings, including increased sugar and ethanol concentrations (in combination with a high solids saccharification which will be reflected in lower capital costs, however this data is currently limited. In this study, several variables such as catalyst loading, retention time and solids loading, were studied using Response Surface Methodology (RSM based on a factorial Central Composite Design (CCD of DA and AL pretreatment on agave bagasse using a range of solids from 3 to 30% (w/w to obtain optimal process conditions for each pretreatment. Subsequently enzymatic hydrolysis was performed using Novozymes Cellic CTec2 and HTec2 presented as total reducing sugar (TRS yield. Pretreated biomass

  7. Ablation of human carious dentin with a nanosecond pulsed laser at a wavelength of 5.85 μm: relationship between hardness and ablation depth

    Science.gov (United States)

    Ishii, Katsunori; Kita, Tetsuya; Yoshikawa, Kazushi; Yasuo, Kenzo; Yamamoto, Kazuyo; Awazu, Kunio

    2014-02-01

    Less invasive treatment and preservation of teeth, referred to as minimal intervention, are strong requirements in dentistry. In our previous study, the fundamental ablation properties of human dentin at wavelengths around 5.8 μm were investigated, and the results indicated that the wavelength of 5.85 μm was optimal for selective removal of carious dentin with less damage to normal dentin. The purpose of this study was to investigate the relationship between the ablation depth and hardness of human dentin including carious lesion. A nanosecond pulsed laser produced by difference-frequency generation was used for irradiations to human carious dentin. It was observed that correlation between ablation depth and Vickers hardness after 2 s laser irradiation at the wavelength of 5.85 μm and the average power density of 30 W/cm2. On the other hand, ablations did not depend on Vickers hardness at the wavelength of 6.00 μm. A nanosecond pulsed laser with the wavelength at 5.85 μm is useful for selective ablation of human carious dentin in accordance with the hardness.

  8. RHEOLOGICAL PROPERTIES AND THE ENERGETIC VALUE OF WHEAT FLOUR SUBSTITUTED BY DIFFERENT SHARES OF WHITE AND BROWN RICE FLOUR

    Directory of Open Access Journals (Sweden)

    Nada Nikolić

    2011-09-01

    Full Text Available In order to produce dough with a lower gluten content, more enriched with rice components and satisfactory rheological properties, the rheological properties, energetic value and cake baking properties of wheat and white or brown rice flour in shares from 3 to 30% (w/w were investigated in this paper. The water absorption in wheat-rice flour mixtures was lower and decreased to 53.5% and 54.0% along with the increase of the white and the brown rice flour share, respectively, than in wheat flour, where it was 58.8%. In the dough made from rice flour, a gluten network had thinner filaments, about 2 and 1 μm in width for white and brown rice flour, respectively, compared to those in the dough from wheat flour only, where it was about 7 μm. The dough from rice flour had almost twice higher gelatinization maximum than the gelatinization maximum of the wheat flour only. The energetic values of the dough from rice flour were smaller than the energetic value of the wheat flour, for only 1.32%. Based on Cluster analysis, the white or brown rice flour share of 20% was pointed out.

  9. Merging micro-meteorology and Landsat imagery to monitor daily evapotranspiration at a regional scale

    Directory of Open Access Journals (Sweden)

    J. M. Sánchez

    2008-01-01

    Full Text Available The objective of this work is to show the operational applicability of a recently proposed model (Sánchez et al., 2008 together with satellite images to monitor surface energy fluxes at a regional scale. In particular, we will focus on the retrieval of daily evapotranspiration because of the particular significance of this flux in the generation of precipitation or in agricultural water resource management. A detailed methodology to apply the Simplified Two- Source Energy Balance method to Landsat imagery is presented. The different surface cropland features are characterized from the CORINE Land Cover maps, and the required meteorological variables are obtained by interpolating the data of a network of agro-meteorological stations distributed within the region of interest. Finally, we show the application of the methodology to three different Landsat images covering the whole Basilicata region (Southern Italy. Maps of the different fluxes including the daily evapotranspiration are performed. Results are compared with some ground measurements, and an analysis is made taking the land use classification as a basis. An accuracy close to 30 W m-2 is obtained.

  10. Power peakings in mixed TRIGA cores

    Energy Technology Data Exchange (ETDEWEB)

    Snoj, Luka [Reactor Physics Division, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)], E-mail: luka.snoj@ijs.si; Ravnik, Matjaz [Reactor Physics Division, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)

    2008-09-15

    Modern Monte-Carlo codes (e.g. MCNP) allow calculation of the power density distribution in 3D geometry assuming detailed geometry without unit-cell homogenization. The power density distribution (and its maximum value-the peaking) can be calculated 'point-wise' with the resolution of approximately 1 mm. Results of the detailed power density distribution calculated by MCNP are presented for 250 kW TRIGA Mark II reactor, assuming various realistic and hypothetical core-loading patterns with focus on the mixed cores. Combinations of 8.5 w/o, 12 w/o, 20 w/o and 30 w/o low-enriched (20%) fresh TRIGA fuel rods are systematically treated in the mixed cores. The power peaking factor value and position strongly depends on the core configuration. Power peakings are usually found in fuel rods with higher uranium content especially if they are inserted near the core centre. The results are conservative and can be applied in planning realistic mixed core-loading patterns.

  11. Power Peaking Factors in Mixed TRIGA cores

    Energy Technology Data Exchange (ETDEWEB)

    Snoj, Luka; Ravnik, Matjaz [' Jozef Stefan' Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)

    2008-10-29

    Modern Monte-Carlo codes (e.g. MCNP) allow calculation of the power density distribution in 3-D geometry assuming detailed geometry without unit-cell homogenization. The power density distribution (and its maximum value - the peaking) can be calculated 'point-wise' with the resolution of approximately 1 mm. Results of the detailed power density distribution calculated by MCNP are presented for 250 kW TRIGA Mark II reactor, assuming various realistic and hypothetical core loading patterns with focus on the mixed cores. Combinations of 8.5 w/o, 12 w/o, 20 w/o and 30 w/o low enriched (20 %) fresh TRIGA fuel rods are systematically treated in the mixed cores. The power peaking factor value and position strongly depends on the core configuration. Power peaking are usually found in fuel rods with higher uranium content especially if they are inserted near the core centre. The results are conservative and can be applied in planning realistic mixed core loading patterns. (authors)

  12. Preparation and characterization of regenerated fiber from the aqueous solution of Bombyx mori cocoon silk fibroin

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Zhenghua [Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Department of Application Engineering, ZheJiang Vocational College of Economic and Trade, HangZhou, ZheJiang 310018 (China); Imada, Takuzo [Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Asakura, Tetsuo, E-mail: asakura@cc.tuat.ac.jp [Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)

    2009-10-15

    The regenerated silk fibers with high strength and high biodegradability were prepared from the aqueous solution of Bombyx mori silk fibroin from cocoons with wet spinning method. Although the tensile strength of the regenerated silk fibroin fiber, 210 MPa is still half of the strength of native silk fiber, the diameter of the fiber is about 100 {mu}m which is suitable for monofilament of suture together with high biodegradability. The high concentration (30%, w/v) of the aqueous solution of the silk fibroin which corresponds to the high concentration in the middle silkgland of silkworm was obtained. This was performed by adjusting the pH of the aqueous solution to 10.4 which corresponds to pK{sub a} value of the OH group of Tyr residues in the silk fibroin. The mixed solvent, methanol/acetic acid (7:3 in volume ratio) was used as coagulant solvent for preparing the regenerated fiber. The structural change of silk fibroin fiber by stretching was monitored with both {sup 13}C solid state NMR and X-ray diffraction methods, indicating that the high strength of the fiber is related with the long-range orientation of the silk fibroin chain with {beta}-sheet structure.

  13. How can aerosols affect the Asian summer monsoon? Assessment during three consecutive pre-monsoon seasons from CALIPSO satellite data

    Directory of Open Access Journals (Sweden)

    J. Kuhlmann

    2010-02-01

    Full Text Available The impact of aerosols above and around the Tibetan Plateau on the Asian Summer Monsoon during pre-monsoon seasons March-April-May 2007, 2008, and 2009 is investigated by means of remote sensing and radiative transfer modelling. Four source regions are found to be responsible for the high aerosol loading around the Tibetan Plateau: the Taklamakan Desert, the Ganges Plains, the Indus Plains, and the Arabian Sea. CALIPSO lidar satellite data, providing vertically resolved images of aerosols, shows aerosol concentrations to be highest in the lower 5 km of the atmosphere with only little amounts reaching the Tibetan Plateau altitude. Using a radiative transfer model we find that aerosol plumes reduce shortwave radiation throughout the Monsoon region in the seasonal average by between 20 and 30 W/m2. Peak shortwave heating in the lower troposphere reaches 0.2 K/day. In higher layers this shortwave heating is partly balanced by longwave cooling. Although high-albedo surfaces, such as deserts or the Tibetan Plateau, increase the shortwave heating by around 10%, the overall effect is strongest close to the aerosol sources. A strong elevated heating which could influence large-scale monsoonal circulations as suggested by previous studies is not found.

  14. How can aerosols affect the Asian summer monsoon? Assessment during three consecutive pre-monsoon seasons from CALIPSO satellite data

    Directory of Open Access Journals (Sweden)

    J. Kuhlmann

    2010-05-01

    Full Text Available The impact of aerosols above and around the Tibetan Plateau on the Asian Summer Monsoon during pre-monsoon seasons March-April-May 2007, 2008, and 2009 is investigated by means of remote sensing and radiative transfer modelling. Four source regions are found to be responsible for the high aerosol loading around the Tibetan Plateau: the Taklamakan Desert, the Ganges Plains, the Indus Plains, and the Arabian Sea. CALIPSO lidar satellite data, providing vertically resolved images of aerosols, shows aerosol concentrations to be highest in the lower 5 km of the atmosphere with only little amounts reaching the Tibetan Plateau altitude. Using a radiative transfer model we find that aerosol plumes reduce shortwave radiation throughout the Monsoon region in the seasonal average by between 20 and 30 W/m2. Peak shortwave heating in the lower troposphere reaches 0.2 K/day. In higher layers this shortwave heating is partly balanced by longwave cooling. Although high-albedo surfaces, such as deserts or the Tibetan Plateau, increase the shortwave heating by around 10%, the overall effect is strongest close to the aerosol sources. A strong elevated heating which could influence large-scale monsoonal circulations as suggested by previous studies is not found.

  15. 1.06-μm Nd:YAG laser coagulation tonsillectomy: an animal study

    Science.gov (United States)

    Wang, Zhi; Pankratov, Michail M.; Volk, Mark S.; Perrault, Donald F., Jr.; Shapshay, Stanley M.

    1995-05-01

    Tonsillectomy is one of the most frequently performed surgeries which is not free from post- operative morbidity. We have developed a non contact photocoagulation technique using 1.06 micrometers Nd:YAG laser and tested its safety and efficacy in an animal model. Eight animals were divided into the laser coagulation group (6 animals) and the laser excision group (2 animals). Tonsils of the laser coagulation animals were irradiated with 8 - 10 W of laser power for 5 - 6 min in a slow painting-like motion over the surface of a tonsil until slight blanching of mucosa was noticed. Tonsils of the laser excision group were resected with 25 - 30 W of 1.06 micrometers Nd:YAG laser power through a contact fiber. The animals were examined endoscopically at 1.5 hrs and at 2, 5, 12, 30, and 42 days post treatment. Atrophic process was followed until total disappearance of tonsillar tissue was observed. The animals were sacrificed at various time intervals and the tonsillar specimens were collected for gross and histological examination. The thermal damage to mucosa and adjacent tissues was minimal which we attribute to a low laser power and cooling from preoperative injection of saline into subcapsular space. The potential advantages of this technique include intact mucosa with no intra- or post-operative bleeding, less pain, and avoidance of general anesthesia. These advantages may enable this surgery to become an in-the-office procedure.

  16. Spin density matrix elements in exclusive {rho}{sup 0} electroproduction on {sup 1}H and {sup 2}H targets at 27.5 GeV beam energy

    Energy Technology Data Exchange (ETDEWEB)

    Airapetian, A.; Deconinck, W.; Gliske, S.; Lorenzon, W. [University of Michigan, Randall Laboratory of Physics, Ann Arbor, MI (United States); Akopov, N.; Akopov, Z.; Avakian, R.; Avetissian, A.; Elbakian, G.; Gharibyan, V.; Marukyan, H.; Taroian, S. [Yerevan Physics Institute, Yerevan (Armenia); Andrus, A.; Lamb, R.; Linden-Levy, L.A.; Makins, N.C.R.; Rubin, J. [University of Illinois, Department of Physics, Urbana, IL (United States); Aschenauer, E.C.; Boettcher, H.; Fabbri, R.; Gabbert, D.; Gregor, I.M.; Guler, H.; Hristova, I.; Kopytin, M.; Liebing, P.; Negodaev, M.; Nowak, W.D.; Stewart, J. [DESY, Zeuthen (Germany); Augustyniak, W.; Marianski, B.; Trzcinski, A.; Zupranski, P. [Andrzej Soltan Institute for Nuclear Studies, Warsaw (Poland); Avetissian, E.; Bianchi, N.; Capitani, G.P.; De Sanctis, E.; Di Nezza, P.; Fantoni, A.; Funel, A.; Hadjidakis, C.; Hasch, D.; Muccifora, V.; Reolon, A.R.; Riedl, C. [Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, Frascati (Italy); Belostotski, S.; Izotov, A.; Jgoun, A.; Kravchenko, P.; Manaenkov, S.I.; Naryshkin, Y.; Veretennikov, D.; Vikhrov, V. [Petersburg Nuclear Physics Institute, Gatchina, Leningrad Region (Russian Federation); Blok, H.P.; Hesselink, W.H.A. [National Institute for Subatomic Physics (Nikhef), Amsterdam (Netherlands); Vrije Universiteit, Department of Physics, Amsterdam (Netherlands); Bonomo, C.; Capiluppi, M.; Ciullo, G.; Contalbrigo, M.; Dalpiaz, P.F.; Giordano, F.; Grebeniouk, O.; Lenisa, P.; Pappalardo, L.L.; Stancari, M.; Statera, M. [Universita di Ferrara, Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara (Italy); Dipartimento di Fisica, Ferrara (Italy); Borissov, A. [DESY, Zeuthen (Germany); Univ. of Glasgow, Dept. of Physics and Astronomy, Glasgow (United Kingdom); Bryzgalov, V.; Gapienko, G.; Gapienko, V.; Ivanilov, A.; Korotkov, V.; Salomatin, Y.; Tchuiko, B. [Inst. for High Energy Physics, Protvino, Moscow Region (Russian Federation)] (and others)

    2009-08-15

    Spin Density Matrix Elements (SDMEs) describing the angular distribution of exclusive {rho}{sup 0} electroproduction and decay are determined in the HERMES experiment with 27.6 GeV beam energy and unpolarized hydrogen and deuterium targets. Eight (fifteen) SDMEs that are related (unrelated) to the longitudinal polarization of the beam are extracted in the kinematic region 1

  17. Biological treatment of textile dyes by agar-agar immobilized consortium in a packed bed reactor.

    Science.gov (United States)

    Patel, Yogesh; Gupte, Akshaya

    2015-03-01

    The decolorization of Acid Maroon V was investigated using bacterial consortium EDPA containing Enterobacter dissolvens AGYP1 and Pseudomonas aeruginosa AGYP2 immobilized in different entrapment matrices. The consortium displayed 96% removal of dye (100 mg/l) within 6 h when immobilized in agar-agar. Under optimum concentrations of agar-agar (3.0% w/v) and cell biomass (0.9 g% w/v), the consortium displayed decolorization for 18 successive batches of Acid Maroon V and also decolorized 14 other different textile dyes. A packed bed reactor under batch mode showed 89% decolorization of dye after 56 repetitive cycles. Under continuous flow mode, maximum color removal was achieved with bed length of 36 cm, hydraulic retention time of 2.66 h, and dye concentration of 100 mg/l. Additionally, the reactor decolorized relatively higher concentrations (100-2000 mg/l) of dye. The synthetic dye wastewater containing five textile dyes was decolorized 92% with 62% COD reduction using an immobilized consortium.

  18. Effect of pH on the functional properties of Arthrospira (Spirulina) platensis protein isolate.

    Science.gov (United States)

    Benelhadj, Sonda; Gharsallaoui, Adem; Degraeve, Pascal; Attia, Hamadi; Ghorbel, Dorra

    2016-03-01

    In the present study, a protein isolate extracted from Arthrospira platensis by isoelectric precipitation was evaluated for its functional properties. The maximum nitrogen solubility was 59.6±0.7% (w/w) at pH 10. The A. platensis protein isolate (API) showed relatively high oil (252.7±0.3g oil/100g API) and water (428.8±15.4g of water/100g of API at pH 10) absorption capacities. The protein zeta potential, the emulsifying capacity, the emulsion ageing stability, the emulsion microstructure and the emulsion opacity as well as the foaming capacity and the foam stability were shown to be greatly affected by pH. Especially, emulsifying and foaming capacities were positively correlated to the protein solubility. Moreover, the API was able to form films when sorbitol (30% (w/w)) was used as plasticizer and to form gels when the API concentration exceeded 12% (w/w). PMID:26471653

  19. In vitro phonophoresis: effect of ultrasound intensity and mode at high frequency on NSAIDs transport across cellulose and rabbit skin membranes.

    Science.gov (United States)

    Meshali, M M; Abdel-Aleem, H M; Sakr, F M; Nazzal, S; El-Malah, Y

    2008-01-01

    The objective of this study was to evaluate the effect of intensity, mode, and duration of ultrasound application on the transport of three nonsteroidal anti-inflammatory drugs (NSAIDs) across cellulose membrane and rabbit-skin. Ibuprofen, piroxicam and diclofenac sodium were used as the model drugs. Studies were performed in vitro using a modified Franz diffusion assembly adapted to a therapeutic ultrasound transducer. Ultrasound had a significant and positive effect on the transport of the model NSAIDs across cellulose and rabbit skin membranes. Increasing ultrasound intensity from 0.5 to 3.0 W/cm2 led to a proportional increase in drug transport. Continuous ultrasound mode was more effective in enhancing drug transport than the pulsed mode. Diclofenac sodium had the least flux and permeability coefficient. This was attributed to its comparatively lower pKa value that renders the drug more ionizable in the buffer solution, consequently reducing its selective penetration through the membranes. This study demonstrated the therapeutic potential of ultrasound in transdermal delivery of NSAIDs and the synergistic effect of temperature and ultrasound operational parameters on drug transport. PMID:18271303

  20. Vanadium(IV/V) complexes of Triapine and related thiosemicarbazones: Synthesis, solution equilibrium and bioactivity.

    Science.gov (United States)

    Kowol, Christian R; Nagy, Nóra V; Jakusch, Tamás; Roller, Alexander; Heffeter, Petra; Keppler, Bernhard K; Enyedy, Éva A

    2015-11-01

    The stoichiometry and thermodynamic stability of vanadium(IV/V) complexes of Triapine and two related α(N)-heterocyclic thiosemicarbazones (TSCs) with potential antitumor activity have been determined by pH-potentiometry, EPR and (51)V NMR spectroscopy in 30% (w/w) dimethyl sulfoxide/water solvent mixtures. In all cases, mono-ligand complexes in different protonation states were identified. Dimethylation of the terminal amino group resulted in the formation of vanadium(IV/V) complexes with considerably higher stability. Three of the most stable complexes were also synthesized in solid state and comprehensively characterized. The biological evaluation of the synthesized vanadium complexes in comparison to the metal-free ligands in different human cancer cell lines revealed only minimal influence of the metal ion. Thus, in addition the coordination ability of salicylaldehyde thiosemicarbazone (STSC) to vanadium(IV/V) ions was investigated. The exchange of the pyridine nitrogen of the α(N)-heterocyclic TSCs to a phenolate oxygen in STSC significantly increased the stability of the complexes in solution. Finally, this also resulted in increased cytotoxicity activity of a vanadium(V) complex of STSC compared to the metal-free ligand. PMID:26349014

  1. Wear testing of friction stir spot welding tools for joining of DP 980 Steel

    Energy Technology Data Exchange (ETDEWEB)

    Ridges, Chris; Miles, Michael; Hovanski, Yuri; Peterson, Jeremy; Steel, Russell

    2011-06-06

    Friction stir spot welding has been shown to be a viable method of joining ultra high strength steel (UHSS), both in terms of joint strength and process cycle time. However, the cost of tooling must be reasonable in order for this method to be adopted as an industrial process. Several tooling materials have been evaluated in prior studies, including silicon nitride and polycrystalline cubic boron nitride (PCBN). Recently a new tool alloy has been developed, where a blend of PCBN and tungsten rhenium (W-Re) was used in order to improve the toughness of the tool. Wear testing results are presented for two of these alloys: one with a composition of 60% PCBN and 40% W-Re (designated as Q60), and one with 70% PCBN and 30% W-Re (designated at Q70). The sheet material used for all wear testing was DP 980. Tool profiles were measured periodically during the testing process in order to show the progression of wear as a function of the number of spots produced. Lap shear testing was done each time a tool profile was taken in order to show the relationship between tool wear and joint strength. For the welding parameters chosen for this study the Q70 tool provided the best combination of wear resistance and joint strength.

  2. Isolation and characterization of soluble sulfated polysaccharide from the red seaweed Glucaric cornea; Isolamento e caracterizacao do polissacarideo sulfatado soluvel extraido da alga vermelha Gracilaria cornea

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Marcia R.S.; Freitas, Ana L.P. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Bioquimica e Biologia Molecular]. E-mail: rubiamelo@yahoo.com; Feitosa, Judith P.A.; Paula, Regina C.M. de [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica]. E-mail: judith@dqoi.ufc.br

    2001-07-01

    The composition, structure and rheological properties of soluble sulphated polysaccharide Glucaric cornea from Brazilian red seaweeds were investigated. The main components of polysaccharide were 3,6-anhydrogalactose (24.7%) and galactose (64.6%). In addition, minor components as 6-O-methyl-galactose (8.5%), glucose (1.5%), xylose (0.7%) and sulfated groups (4.8%) were detected. Comparison between sulphates content determined by Ft-IR spectroscopy and micro elemental analysis was made. Data from {sup 13}C NMR and FT-IR provided evidence of sulphation in C-4 and C-6 of galactose. No gelation with 1.5, 2.0 and 3.0 % (w/v) aqueous solution was observed, even cooled up to 4 deg C. GPC indicated two majors polysaccharide fractions of M{sub pk} 7.4 x 10{sup 4} and 1.8 x 10{sup 4} g/mol and a minor fraction of M{sub pk} 2.1 x 10{sup 6} g/mol. (author)

  3. Screening and characterization of a high taxol producing fungus by protoplast mutagenesis

    Institute of Scientific and Technical Information of China (English)

    Zhao Kai; Sun Qingshen; Zhang Yanjun; Ping Wenxiang; Jin Tao; Zhou Dongpo

    2009-01-01

    The preparation, regeneration and mutagenesis of the taxol-producing fungus UV40-19 protoplasts were discussed in the experiment. Totally 42 strains displayed hygromycin resistance. Six strains were found to be positive mutants when screened on plate containing 90μg/mL hygromycin. One hereditarily stable strain UN05-6 was obtained, which raised the taxol yield from (376.38±8.41)μg/L to (493.12±11.36)μg/L. The optimal conditions for the preparation, regeneration and mutagenesis of the taxol producing fungus UV40-19 were as follows: 1)enzymolysis in a solution containing 3% lywallzyme, 4% snailase, 1% lysozyme and 3% cellulose at 30℃ water bath, pH5.5~6.0 for 5h; 2) The prepared protoplasts were regenerated by using bilayer plate culturing method; 3)To mutagenize the fungus UV40-19, the protoplast suspension was treated with 0.8mg/mL NTG for 15min, followed by UV irradiation (30W, 30cm distance)for 40s under magnetic stirring. The purified products of the fungus UN05-6 fermented extracts have significant inhibitive effects on SMMC-7721 cell.

  4. STUDY OF LACTOSE INTOLERANCE IN CHILDREN BELOW 24 M ONTHS

    Directory of Open Access Journals (Sweden)

    Shabd Singh

    2013-05-01

    Full Text Available ABSTRACT: OBJECTIVE: To study the incidence of transient lactose intole rance in children below 24 months and to determine the need of discon tinuation of breast feeding and necessity of lactose free formula. MATERIAL AND METHODS: Randomly selected 100 children below 24 months of age, who were admitted in department of p ediatrics, S.S. Medical College and Associated G.M. Hospital Rewa, 70 of them were grou ped as cases with diarrhea, abdominal distention, vomiting, perianal excoriation and 30 w ere age and sex matched control. After collection of stool, pH, reducing substances in sto ol was determined and osazone test was performed to identify the types of reducing substan ces. RESULT: Out of 70 cases with diarrhoea, 22 (31.4% were found to have evidence o f lactose intolerance. Besides loose motion, in lactose intolerance positive cases, most common presenting symptoms were abdominal distention, perianal excoriation and vomiting. Inci dence of lactose intolerance was less in children who were on exclusive breast feeding till 6 months. In lactose intolerance positive as well as negative group duration of diarrhea after a dmission was same inspite of continuation of breast feeding. CONCLUSION: - Presence of abdominal distention, frothy character of stool, and perianal excoriation are suggestive of lactose into lerance. Lactose free formula and withdrawal of breast milk are not necessary in children with a cute diarrhea and persistent diarrhea having transient lactose intolerance.

  5. Compounding slow-release capsules: a comprehensive review and an Excel spreadsheet for faster calculations of excipients.

    Science.gov (United States)

    Zur, Eyal

    2013-01-01

    Compounding pharmacists throughout the world are compounding a special type of capsule called "slow-release." This type of capsule is a compounding pharmacy application of the commercial hydrophilic matrix tablets. It is a relatively simple system that allows formulating a robust, reliable, and consistent drug system based on 30% w/w to 40% w/w of specific types of hydroxypropyl methylcellulose. The main purpose of these capsules is to attenuate the drug release when there is a clinical need and no commercial medication exists. Five in vitro trials verified and proved this kind of preparation can be compounded by specialized pharmacists achieving substantial attenuation of drug release that resembles the pharmacokinetic profiles of commercial slow-release medications. An in-depth explanation of the mechanism of action of the slow-release capsules is provided. Since the pharmaceutical calculations needed to compound this preparation are time consuming, a suggestion of a faster way to perform these calculations by using a special Excel spreadsheet is provided. The article demonstrates a special table with a comparison between the specifications, results, and conclusions of the five in vitro trials that evaluated the pharmacokinetic rates of compounded slow-release capsules. The regulatory aspect of compounding slow-release capsules is also discussed.

  6. Catalytic decomposition of methane to COx-free hydrogen and carbon nanotubes over Co–W/MgO catalysts

    Directory of Open Access Journals (Sweden)

    Ahmed E. Awadallah

    2015-09-01

    Full Text Available Bimetallic catalysts containing a series of Co/W at 40/10, 30/20, 20/30 and 10/40 wt% supported on MgO with a total metal content of 50 wt% were prepared and used for the catalytic decomposition of methane to COx-free hydrogen and multi-walled carbon nanotubes (MWCNTs. The solid fresh and exhausted catalysts were characterized structurally and chemically through XRD, TPR, BET, TGA, TEM and Raman spectroscopy. The 40%Co–10%W/MgO catalyst exhibited the highest activity for the production of both hydrogen and MWCNTs. The formation of a large amount of non-interacted Co3O4 species is considered as the main reason for the catalyst superiority in its activity. On the contrary, catalysts formulations of 20%Co–30%W and 10%Co–40%W demonstrated the formation of a large amount of hardly reducible CoWO4 and MgWO4 particles causing lower activity of these catalysts toward methane decomposition as evidenced through the XRD and TPR results.

  7. Gain-switched CW fiber laser for improved supercontinuum generation in a PCF

    DEFF Research Database (Denmark)

    Larsen, Casper; Noordegraaf, Danny; Skovgaard, P.M.W.;

    2011-01-01

    We demonstrate supercontinuum generation in a PCF pumped by a gain-switched high-power continuous wave (CW) fiber laser. The pulses generated by gain-switching have a peak power of more than 700 W, a duration around 200 ns, and a repetition rate of 200 kHz giving a high average power of almost 30 W....... By coupling such a pulse train into a commercial nonlinear photonic crystal fiber, a supercontinuum is generated with a spectrum spanning from 500 to 2250 nm, a total output power of 12 W, and an infrared flatness of 6 dB over a bandwidth of more than 1000 nm with a power density above 5 dBm/nm (3 m......W/nm). This is considerably broader than when operating the same system under CW conditions. The presented approach is attractive due to the high power, power scalability, and reduced system complexity compared to picosecond-pumped supercontinuum sources. © 2011 Optical Society of America....

  8. Cesium-137 inventories in Alaskan Tundra, lake and marine sediments: An indicator of recent organic material transport?

    International Nuclear Information System (INIS)

    Tundra sampling was accomplished in 1989--1990 at Imnavait Creek, Alaska (68 degree 37' N, 149 degree 17' W). Inventories of 137Cs (102--162 mBq/cm2) are close to expectations, based upon measured atmospheric deposition for this latitude. Accumulated inventories of 137Cs in tundra decrease by up to 50% along a transect to Prudhoe Bay (70 degree 13' N, 148 degree 30' W). Atmospheric deposition of 137Cs decreased with latitude in the Arctic, but declines in deposition would have been relatively small over this distance (200 km). This suggests a recent loss of 137Cs and possibly associated organic matter from tundra over the northern portions of the transect between Imnavait Creek and Prudhoe Bay. Sediments from Toolik Lake (68 degree 38' N, 149 degree 38' W) showed widely varying 137Cs inventories, from a low of 22 mBq/cm2 away from the lake inlet, to a high between 140 to >200 mBq/cm2 near the main stream inflow. This was indicative of recent accumulation of cesium and possibly organic material associated with it in arctic lakes, although additional sampling is needed

  9. Effect of squalane on mebendazole-loaded Compritol® nanoparticles.

    Science.gov (United States)

    Graves, Richard A; Ledet, Grace A; Nation, Cedric A; Pramar, Yashoda V; Bostanian, Levon A; Mandal, Tarun K

    2015-01-01

    The objective of this study is to develop nanostructured lipid formulations of Compritol for the delivery of mebendazole. The formulations were prepared with Compritol 888 ATO, squalane, and Pluronic F68. Nine batches with different amounts of modifier, squalane, and drug were prepared. The formulations were characterized by evaluating particle size, morphology, and zeta potential. The thermal properties of the formulations were analyzed by differential scanning calorimetry (DSC). The encapsulation efficiency of each formulation and the drug release rates from each formulation were quantified by UPLC. The particles were spherical and had median particle sizes between 300 and 600 nm (50th percentile). A linear relationship was observed between Compritol/squalane composition and the melting point of the mixture. The DSC scans of the formulations revealed some recrystallization of the drug from the formulations, and the amount of recrystallization correlated with the amount of squalane in the formulation. Approximately, 70% efficiency of encapsulation was observed in the formulations with 30% (w/w) squalane, and these formulations also had faster dissolution rates compared to the other formulations. Overall, the formulations with 30% squalane are the preferred formulation for future testing.

  10. Effect of squalane on mebendazole loaded Compritol® nanoparticles

    Science.gov (United States)

    Graves, Richard A.; Ledet, Grace A.; Nation, Cedric A.; Pramar, Yashoda V.; Bostanian, Levon A.; Mandal, Tarun K.

    2015-01-01

    The objective of this study is to develop nanostructured lipid formulations (NLF) of Compritol for the delivery of mebendazole. The formulations were prepared with Compritol 888 ATO, squalane, and Pluronic F68. Nine batches with different amounts of modifier, squalane, and drug were prepared. The formulations were characterized by evaluating particle size, morphology, and zeta potential. The thermal properties of the formulations were analyzed by differential scanning calorimetry (DSC). The encapsulation efficiency of each formulation and the drug release rates from each formulation were quantified by UPLC. The particles were spherical and had median particle sizes between 300 and 600 nm (50th percentile). A linear relationship was observed between Compritol/squalane composition and the melting point of the mixture. The DSC scans of the formulations revealed some recrystallization of the drug from the formulations, and the amount of recrystallization correlated with the amount of squalane in the formulation. Approximately 70% efficiency of encapsulation was observed in the formulations with 30% (w/w) squalane, and these formulations also had faster dissolution rates compared to the other formulations. Overall, the formulations with 30% squalane are the preferred formulation for future testing. PMID:26062393

  11. Bacterial cellulose membrane as flexible substrate for organic light emitting devices

    Energy Technology Data Exchange (ETDEWEB)

    Legnani, C.; Vilani, C. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); Calil, V.L. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); LOEM-Molecular Optoelectronic Laboratory-Physics Department-PUC-Rio, Rio de Janeiro, RJ (Brazil); Barud, H.S. [Institute of Chemistry, Sao Paulo State University-UNESP, CP 355 Araraquara, SP (Brazil); Quirino, W.G. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); Achete, C.A. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); COPPE-Programa de Engenharia Metalurgica e de Materiais, UFRJ, Rio de Janeiro, RJ (Brazil); Ribeiro, S.J.L. [Institute of Chemistry, Sao Paulo State University-UNESP, CP 355 Araraquara, SP (Brazil); Cremona, M. [CeDO-Organic Device Center, Dimat-Dimat, Inmetro, Duque de Caxias, RJ (Brazil); LOEM-Molecular Optoelectronic Laboratory-Physics Department-PUC-Rio, Rio de Janeiro, RJ (Brazil)], E-mail: cremona@fis.puc-rio.br

    2008-12-01

    Bacterial cellulose (BC) membranes produced by gram-negative, acetic acid bacteria (Gluconacetobacter xylinus), were used as flexible substrates for the fabrication of Organic Light Emitting Diodes (OLED). In order to achieve the necessary conductive properties indium tin oxide (ITO) thin films were deposited onto the membrane at room temperature using radio frequency (r.f.) magnetron sputtering with an r.f. power of 30 W, at pressure of 8 mPa in Ar atmosphere without any subsequent thermal treatment. Visible light transmittance of about 40% was observed. Resistivity, mobility and carrier concentration of deposited ITO films were 4.90 x 10{sup -4} Ohm cm, 8.08 cm{sup 2}/V-s and - 1.5 x 10{sup 21} cm{sup -3}, respectively, comparable with commercial ITO substrates. In order to demonstrate the feasibility of devices based on BC membranes three OLEDs with different substrates were produced: a reference one with commercial ITO on glass, a second one with a SiO{sub 2} thin film interlayer between the BC membrane and the ITO layer and a third one just with ITO deposited directly on the BC membrane. The observed OLED luminance ratio was: 1; 0.5; 0.25 respectively, with 2400 cd/m{sup 2} as the value for the reference OLED. These preliminary results show clearly that the functionalized biopolymer, biodegradable, biocompatible bacterial cellulose membranes can be successfully used as substrate in flexible organic optoelectronic devices.

  12. Nano-Welding of Multi-Walled Carbon Nanotubes on Silicon and Silica Surface by Laser Irradiation

    Directory of Open Access Journals (Sweden)

    Yanping Yuan

    2016-02-01

    Full Text Available In this study, a continuous fiber laser (1064 nm wavelength, 30 W/cm2 is used to irradiate multi-walled carbon nanotubes (MWCNTs on different substrate surfaces. Effects of substrates on nano-welding of MWCNTs are investigated by scanning electron microscope (SEM. For MWCNTs on silica, after 3 s irradiation, nanoscale welding with good quality can be achieved due to breaking C–C bonds and formation of new graphene layers. While welding junctions can be formed until 10 s for the MWCNTs on silicon, the difference of irradiation time to achieve welding is attributed to the difference of thermal conductivity for silica and silicon. As the irradiation time is prolonged up to 12.5 s, most of the MWCNTs are welded to a silicon substrate, which leads to their frameworks of tube walls on the silicon surface. This is because the accumulation of absorbed energy makes the temperature rise. Then chemical reactions among silicon, carbon and nitrogen occur. New chemical bonds of Si–N and Si–C achieve the welding between the MWCNTs and silicon. Vibration modes of Si3N4 appear at peaks of 363 cm−1 and 663 cm−1. There are vibration modes of SiC at peaks of 618 cm−1, 779 cm−1 and 973 cm−1. The experimental observation proves chemical reactions and the formation of Si3N4 and SiC by laser irradiation.

  13. Exclusive J/{psi} production in deep inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Voss, K.C.

    2004-10-15

    The exclusive electroproduction of J/{psi} mesons, ep{yields}ep J/{psi}, is studied with the ZEUS detector at HERA for virtualities of the exchanged photon in the range 2 < Q{sup 2} < 100 GeV{sup 2}, using an integrated luminosity of 83 pb{sup -1}. The photon-proton centre-of-mass energy is in the range 30 < W < 220 GeV and the squared four-momentum transfer at the proton vertex vertical stroke t vertical stroke <1 GeV{sup 2}. The cross-sections and the decay angular distributions are presented as functions of Q{sup 2}, W and t. The effective parameters of the Pomeron trajectory are determined. The spin-density matrix elements, calculated from the decay angular distributions, are used to test the hypothesis of s-channel helicity conservation. The ratio of the longitudinal and transverse cross-sections {sigma}{sub L}/{sigma}{sub T} is measured as a function Q{sup 2}, W and t. The results are compared to QCD inspired models. (orig.)

  14. Mechanism of Expansion of Mortars with Limestone Filler due to External Sulfate Attack

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The mechanism of expansion of mortars and pastes with limestone filler due to external sulfate attack was studied.Mortars and pastes made at water to solid ratios of 0.45, 0.5, 0.6 from Portland Cement (OPC) with 0%, 20% or 30% (w/w) limestone filler (LF) were cured in a 95±1% RH moist room at 20±1 ℃ for 14 or 28 days. They subsequently were immersed in 5% Na2SO4(0.35 M) solution at ambient temperature (1~35 ℃). The expansion of the specimens was measured every month, and selected samples were examined by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results indicate that mortars with 20% LF show larger expansion than that of OPC mortars at up to 9 months of exposure,and the amount of gypsum in both mortars and pastes with LF is much more than that in mortars and pastes without LF. Therefore, it is reasonable to conclude that the formation of massive gypsum leads to the lager expansion of the mortars and pastes containing 20% LF. These behaviors may be explained by the changes in hydration products due to the addition of LF.

  15. Palynology of cushion bogs of the Cordillera Pelada, Province of Valdivia, Chile

    Science.gov (United States)

    Heusser, Calvin J.

    1982-01-01

    Fossil pollen identified in the earliest sediments of three cushion bogs in the Cordillera Pelada (40°10'S, 73°30'W) dated 10,425 14C yr B.P. includes the subantarctic species Dacrydium fonckii, Tetroncium magellanicum, Astelia pumila, Gaimardia australis, Donatia fascicularis, and Drosera uniflora. All grow today in the Cordillera Pelada and range poleward to the southernmost Province of Magallanes; one species, Drapetes muscosa, included with the pollen of these plants in the earliest record, is no longer a constituent of the flora but is limited only to subantarctic Chile. Available evidence indicates that plants survived the last glaciation north of the glacial border with the course of postglacial migration southward following the wastage of the glacier complex. Holocene climatic and vegetational changes in the Cordillera Pelada are interpreted in the context of regional reconstructions which show maximum warmth about 9000 yr ago with a pronounced dry period lasting from 9000 to 6500 yr B.P. Maximum precipitation was later reached around 4000 yr ago but has decreased overall since then. The regional decline of the endemic gymnosperm Fitzroya cupressoides, which today is extensively destroyed in the Cordillera Pelada, follows this decrease in precipitation. These climatic data suggest a net south ward shift in the zone of westerly winds that bring rainfall to the region over the past 4000 yr.

  16. Bioinspired Nanoparticulate Medical Glues for Minimally Invasive Tissue Repair.

    Science.gov (United States)

    Lee, Yuhan; Xu, Chenjie; Sebastin, Monisha; Lee, Albert; Holwell, Nathan; Xu, Calvin; Miranda Nieves, David; Mu, Luye; Langer, Robert S; Lin, Charles; Karp, Jeffrey M

    2015-11-18

    Delivery of tissue glues through small-bore needles or trocars is critical for sealing holes, affixing medical devices, or attaching tissues together during minimally invasive surgeries. Inspired by the granule-packaged glue delivery system of sandcastle worms, a nanoparticulate formulation of a viscous hydrophobic light-activated adhesive based on poly(glycerol sebacate)-acrylate is developed. Negatively charged alginate is used to stabilize the nanoparticulate surface to significantly reduce its viscosity and to maximize injectability through small-bore needles. The nanoparticulate glues can be concentrated to ≈30 w/v% dispersions in water that remain localized following injection. With the trigger of a positively charged polymer (e.g., protamine), the nanoparticulate glues can quickly assemble into a viscous glue that exhibits rheological, mechanical, and adhesive properties resembling the native poly(glycerol sebacate)-acrylate based glues. This platform should be useful to enable the delivery of viscous glues to augment or replace sutures and staples during minimally invasive procedures.

  17. Soil Physical Constraints on Intrinsic Biodegradation of Petroleum Vapors in a Layered Subsurface.

    Science.gov (United States)

    Kristensen, Andreas H; Henriksen, Kaj; Mortensen, Lars; Scow, Kate M; Moldrup, Per

    2010-02-01

    Naturally occurring biodegradation of petroleum hydrocarbons in the vadose zone depends on the physical soil environment influencing field-scale gas exchange and pore-scale microbial metabolism. In this study, we evaluated the effect of soil physical heterogeneity on biodegradation of petroleum vapors in a 16-m-deep, layered vadose zone. Soil slurry experiments (soil/water ratio 10:30 w/w, 25°C) on benzene biodegradation under aerobic and well-mixed conditions indicated that the biodegradation potential in different textured soil samples was related to soil type rather than depth, in the order: sandy loam > fine sand > limestone. Similarly, O(2) consumption rates during in situ respiration tests performed at the site were higher in the sandy loam than in the fine sand, although the difference was less significant than in the slurries. Laboratory and field data generally agreed well and suggested a significant potential for aerobic biodegradation, even with nutrient-poor and deep subsurface conditions. In slurries of the sandy loam, the biodegradation potential declined with increasing in situ water saturation (i.e., decreasing air-filled porosity in the field). This showed a relation between antecedent undisturbed field conditions and the slurry biodegradation potential, and suggested airfilled porosity to be a key factor for the intrinsic biodegradation potential in the field. PMID:21617737

  18. Formulation and optimization of ethosomes for transdermal delivery of ropinirole hydrochloride.

    Science.gov (United States)

    Mishra, Ashish D; Patel, C N; Shah, Dinesh R

    2013-10-01

    The present study focuses on the formulation of ethosomal gel of ropinirole hydrochloride (ropinirole HCl), an anti-Parkinsonian drug, for delivery as a carrier for transdermal application. The ethosomes were prepared using different concentrations of phospholipids (2-5 % w/v), ethanol (20-50 % w/v), ropinirole HCl (5 % w/v) and water. They were optimized using 3(2) full factorial designs to study the effect of independent variables, concentrations of ethanol and lecithin on dependent variables, entrapment efficiency and in-vitro drug release at 24 hrs. The drug release profile exhibited Higuchi's and zero order kinetics. From the regression analysis, it was observed that independent variables had significant effect on response variables. Formulations were optimized using contour plot and response surface plot. The optimized formulation was found to be RS10 containing 30 % w/v ethanol and 4% w/v lecithin. The optimized formulation was evaluated for assay, particle characteristics, zeta potential, skin retention and stability. Ethosomal gel was prepared by incorporation of optimized ethosomal suspension into gel base. The ethosomal gel was characterized for physical appearance, pH, content uniformity, rheological behaviour, skin-retention, in-vitro and in-vivo drug release and stability. From the results it can fairly be concluded that ethosomes are capable of delivering ropinirole hydrochloride into systemic circulation by transdermal route. The amounts thus delivered are also equitable to those delivered orally and are delivered at a rate slow enough to achieve longer blood levels. PMID:23410071

  19. Surface nanomodification of cotton fiber for flame retardant application.

    Science.gov (United States)

    Paosawatyanyong, Boonchoat; Jermsutjarit, Piyarat; Bhanthumnavin, Worawan

    2012-01-01

    This paper presents efficient surface modification methodology to increase fire resistance properties of cotton by radio frequency (RF) plasma-induced graft copolymerization of vinyl phosphate ester as nanometer residue structure onto cotton surface. Methacryloyloxyethyl diphenyl phosphate (MEDP) monomer was synthesized and grafted onto the surface of cotton fabric by argon RF plasma at ambient temperature. Under optimum RF power (30 W), amounts of MEDP and N,N methylenebisacrylamide cross linking agent were varied to obtain optimum graft copolymerization conditions. Untreated and treated cotton were characterized by attenuated total reflectance infrared (ATR-IR) spectroscopy to investigate their functional group characteristics. This showed a strong covalent attachment between the surface of cotton and flame retardant material as the carbonyl functionality of the MEDP was clearly observed in the spectra. Scanning electron microscopic (SEM) analysis also showed grafted material as nanometer residue on cotton surface. Thermogravimetric analysis (TGA) revealed that the decomposition of phosphorus compound which occurs at lower temperature than the cotton itself resulted in the formation of char which covers cotton surface. This protects the fabric surface from further burning, therefore, higher amounts of remaining materials were observed as char in all cases. Furthermore, limiting oxygen index (LOI) had increased from 19 in untreated to 28 in grafted cotton. Detailed analysis on structural and thermal properties as well as surface grafting efficiency are presented. PMID:22524051

  20. Enhanced Coagulation Efficiency of Moringa Oleifera Seeds Through Selective Oil Extraction

    Directory of Open Access Journals (Sweden)

    Suleyman A. Muyibi

    2012-10-01

    Full Text Available In this laboratory based study, varying quantities of oil, corresponding to 20 % w/w, 25 % w/w and 30 % w/w kernel weight extracted from Moringa oleifera seeds ( S1, S2, S3 respectively  were applied in the coagulation of model turbid water (kaolin suspension and turbid river water samples from River Batang Kali and River Selangor in Malaysia to determine the percentage oil removed which gave the best coagulation efficiency. For model turbid water (kaolin suspension coagulation of low turbidity of 35 NTU, medium turbidity of 100 NTU and high turbidity of 300 NTU, sample S2  gave the best turbidity removal corresponding to 91.7%, 95.5% and 99% respectively. Application of sample S2 to River Batang Kali with low initial turbidity of 32 NTU and high initial turbidity of 502 NTU gave a highest turbidity removal of 69% and 99% respectively. Application to River Selangor with medium initial turbidity- of 87 NTU and high initial turbidity of 466 NTU gave a highest residual turbidity' of 94% and 98.9%,  respectively.Key words: Moringa oleifera seed, selective oil extraction, coagulation, model turbid water (kaolin suspension, river water, turbidity removal.

  1. Non-chromatographic speciation of chromium at sub-ppb levels using cloud point extraction in the presence of unmodified silver nanoparticles.

    Science.gov (United States)

    López-García, Ignacio; Vicente-Martínez, Yesica; Hernández-Córdoba, Manuel

    2015-01-01

    The cloud point extraction (CPE) of silver nanoparticles (AgNPs) by Triton X-114 allows chromium (III) ions to be transferred to the surfactant-rich phase, where they can be measured by electrothermal atomic absorption spectrometry. Using 20 mL sample and 50 μL Triton X-114 (30% w/v), the enrichment factor was 1150, and calibration graphs were obtained in the 5-100 ng L(-1) chromium range in the presence of 5 µg L(-1) AgNPs. Speciation of trivalent and hexavalent chromium was achieved by carrying out two CPE experiments, one of them in the presence of ethylenediaminetetraacetate. While in the first experiment, in absence of the complexing agent, the concentration of total chromium was obtained, the analytical signal measured in the presence of this chemical allowed the chromium (VI) concentration to be measured, being that of chromium (III) calculated by difference. The reliability of the procedure was verified by using three standard reference materials before applying to water, beer and wine samples.

  2. Contact force assessment in catheter ablation of atrial fibrillatio

    Directory of Open Access Journals (Sweden)

    Josef Kautzner; Petr Peichl

    2014-04-01

    Full Text Available The efficacy of catheter ablation of atrial fibrillation (AF remains limited. Increase of success would require more durable lesions without increased risk of steam pop and cardiac perforation. Recently, novel technologies have been developed to estimate real-time catheter-tissue contact force (CF. This paper reviews three available tools for assessment of CF and data on experimental or clinical experience. Experimental data with open-irrigated catheter showed that lesion size was greater with applications of lower power (like 30 W and greater CF (e.g. 30 to 40 g than vice versa. Impedance drop in the first 5 seconds was significantly correlated to catheter CF. Perforation was achieved more rapidly with the ablation catheter in a sheath despite the same CF because the sheath prevents catheter buckling. Clinical experience confirmed poor relationship between CF and either unipolar amplitude, bipolar amplitude, or impedance. Within the left atrium, the most common high CF site was found at the anterior/rightward LA roof, directly beneath the ascending aorta (confirmed by merging the CT image and map. Importantly, several studies showed that the use of CF leads to shorter procedure with less fluoroscopy time and less RF applications. CF assessment was also found to be associated with higher proportion of durable lesions. Finally, pilot studies showed that CF measurement could be associated with better clinical efficacy AF ablation.

  3. Preparation of hydroxypropyl corn and amaranth starch hydrolyzate and its evaluation as wall material in microencapsulation.

    Science.gov (United States)

    Kshirsagar, Amol C; Singhal, Rekha S

    2008-06-01

    Hydroxypropylation of starches lends it useful physicochemical and functional properties that are industrially important. The literature on hydroxypropylation using organic solvents for obtaining higher molar substitution (MS) is scantily available. The present work reports on hydroxypropylation of corn and a waxy amaranth starch to different MS with propylene oxide in an alkaline-organic medium (isopropanol). The synthesis was followed in terms of MS. The parameters optimized were starch:isopropanol ratio (w/w), reaction temperature, reaction time and the quantity of alkali required in the process. A maximal MS of 0.180 and 0.162 were obtained for hydroxypropyl corn starch (HPSC) and hydroxypropyl amaranth starch (HPSA), respectively. Enzymatic hydrolysis of the HPSC and HPSA of the above MS was carried out on a 30% (w/v) solution at a pH of 6.5 and 95°C for varying time periods using 0.1% (w/w based on starch) bacterial α-amylase, termamyl. The hydrolysis was terminated by adjusting the pH to 3.5 using 0.1N HCl. The hydrolyzates were characterized in terms of dextrose equivalent and viscosity. The hydrolyzate obtained after 3h of hydrolysis was spray dried and compared to gum arabic with respect to encapsulation of model flavourings, orange oil and lemon oil. PMID:26065758

  4. Characterisation of spray dried soy sauce powders made by adding crystalline carbohydrates to drying carrier.

    Science.gov (United States)

    Wang, Wei; Zhou, Weibiao

    2015-02-01

    This study aimed to reduce stickiness and caking of spray dried soy sauce powders by introducing a new crystalline structure into powder particles. To perform this task, soy sauce powders were formulated by using mixtures of cellulose and maltodextrin or mixtures of waxy starch and maltodextrin as drying carriers, with a fixed carrier addition rate of 30% (w/v) in the feed solution. The microstructure, crystallinity, solubility as well as stickiness and caking strength of all the different powders were analysed and compared. Incorporating crystalline carbohydrates in the drying carrier could significantly reduce the stickiness and caking strength of the powders when the ratio of crystalline carbohydrates to maltodextrin was above 1:5 and 1:2, respectively. X-ray Diffraction (XRD) results showed that adding cellulose or waxy starch could induce the crystallinity of powders. Differential Scanning Calorimetry (DSC) results demonstrated that the native starch added to the soy sauce powders did not fully gelatinize during spray drying. PMID:25172729

  5. Gastroprotective Effect of Freeze Dried Stripped Snakehead Fish (Channa striata Bloch.) Aqueous Extract against Aspirin Induced Ulcerogenesis in Pylorus Ligated Rats.

    Science.gov (United States)

    Ali Khan, Mohammed Safwan; Mat Jais, Abdul Manan; Hussain, Javeed; Siddiqua, Faiza; Gopala Reddy, A; Shivakumar, P; Madhuri, D

    2014-01-01

    Channa striata (Bloch.) is a fresh water fish belonging to the family Channidae. The stripped snakehead fish possesses wide range of medicinal properties. In view of traditional use of C. striata for wound healing, the present study was undertaken to investigate the beneficial effects of orally administered freeze dried aqueous extract of Channa striata (AECS) in experimentally induced gastric ulcers in Wistar rats. Aspirin induced ulcerogenesis in pyloric ligation model was used for the assessment of antiulcer activity and Ranitidine (50 mg/kg) was employed as the standard drug. The various gastric parameters like volume of gastric juice, pH, free and total acidities, ulcer index, and levels of antioxidant enzymes like catalase, superoxide dismutase, and lipid peroxidation marker malondialdehyde were determined. AECS at concentrations of 40% and 50% w/v significantly decreased the volume of gastric juice and increased the levels of catalase while considerable decrease in free and total acidities and increase in superoxide dismutase were observed with the treatment of standard drug and AECS (50% w/v). All the test doses of AECS markedly decreased ulcer index and malondialdehyde compared to the standard drug whereas AECS 30% w/v did not alter volume of gastric juice, pH, free and total acidities, catalase, and superoxide dismutase. From these findings, it can be concluded that AECS is devoid of acid neutralizing effects at lower doses and possesses antisecretory and antiulcer activities and this could be related to its antioxidant mechanism.

  6. Processing of post-consumer HDPE reinforced with wood flour: Effect of functionaliation methodology

    Science.gov (United States)

    Catto, A. L.; Montagna, L. S.; Rossini, K.; Santana, R. M. C.

    2014-05-01

    A way very interesting used in the reuse of waste cellulose derivatives such as wood flour is its incorporation into thermoplastics matrix. As the olefinic polymers have no interaction with cellulose derivatives, some chemical treatments have been used in the modification of vegetable fibers, to increase the interfacial adhesion between the cellulosic reinforcement and the polymeric matrix. In this sense, the objective of this study was to evaluate the influence of the methodology of the incorporation of compatibilizer agent (CA) in polyolefin matrix and evaluate the mechanical and morphological properties of composites. HDPE, wood flour from Eucalyptus grandis species (EU) and graftized polyethylene with maleic anhydride (CA) were used in composites, being extruded and after injection molding. The mixtures were processed in a single screw extruder (L/D: 22), with the temperature profile from 170° to 190°C. In a first step, the materials were processed together in the extruder, and after the samples were injected a temperature of 185°C and pressure of 600 bar. In a second step, the HDPE with the compatibilizer agent were first processed in the extruder in order to functionalize the polyolefin, and added after the wood flour (EU) sieved (30% w/w). Results showed that composites with CA had a higher mechanical performance compared to nocompatibilized. Also showed that composites compatibilized previously in the extruder with CA had better performance in comparison to other where the polymer matrix was not previously compatibilized.

  7. Design and Operating Performance of Cryocooled Helium Thermosiphon Loops for HTS Transformers

    Science.gov (United States)

    Schwenterly, S. W.; Cole, M. J.; Demko, J. A.; Pleva, Edward F.; Hazelton, D. W.

    2004-06-01

    Since the large coils in a cryocooled HTS utility transformer can be located more than a meter away from the cryocooler cold heads, conductive cooling would require very large, heavy thermal links to keep temperature differentials small. Under a U.S. Department of Energy (USDOE) Superconductivity Partnership with Industry (SPI) agreement with Waukesha Electric Systems (WES), SuperPower Inc. (SP), Energy East (EE), and Oak Ridge National Laboratory (ORNL), we have developed a closed-loop helium system that couples the coils to the cold heads using natural convection cooling. The loop operates on a single-phase thermosiphon principle at temperatures and pressures from 20 to 45 K and 10 to 20 bars, and needs no external compressor to maintain helium gas circulation. Design procedures for the heat exchangers on both the cold heads and coils and for the interconnecting piping will be summarized. A 30-W cooling loop was successfully operated on a 1-MVA prototype transformer. A 350-W system for a 5/10-MVA prototype transformer has been built and tested with a dummy load over a wide range of heat loads corresponding to the range from normal transformer operation to two times (2×) overload. Later, this system successfully cooled down the 4.5-ton cold mass of the transformer to temperatures below 30 K. Design details of the hardware and performance of the assembled systems will be summarized.

  8. High capacity 30 K remote helium cooling loop

    Science.gov (United States)

    Trollier, T.; Tanchon, J.; Icart, Y.; Ravex, A.

    2014-01-01

    Absolut System has built several 50 K remote helium cooling loops used as high capacity and very low vibration cooling source into large wavelength IR detectors electro-optical characterization test benches. MgB2 based superconducting electro-technical equipment's under development require also distributed high cooling power in the 20-30 K temperature range. Absolut System has designed, manufactured and tested a high capacity 30 K remote helium cooling loop. The equipment consists of a CRYOMECH AL325 type cooler, a CP830 type compressor package used as room temperature circulator and an intermediate LN2 bath cooling used between two recuperator heat exchangers (300 K-77 K and 77 K-20 K). A cooling capacity of 30 W @ 20 K or 80 W @ 30 K has been demonstrated on the application heat exchanger, with a 4-meter remote distance ensured by a specifically designed gas circulation flexible line. The design and the performance will be reported in this paper.

  9. The Estimation Surface Latent Heat Flux Over the Ocean and its Relationship to Marine Atmospheric Boundary Layer (MABL) Structure

    Science.gov (United States)

    Palm, Stephen P.; Schwemmer, Geary K.; Vandemark, Doug; Evans, Keith; Miller, David O.

    1999-01-01

    A new technique combining active and passive remote sensing instruments for the estimation of surface latent heat flux over the ocean is presented. This synergistic method utilizes aerosol lidar backscatter data, multi-channel infrared radiometer data and microwave scatterometer data acquired onboard the NASA P-3B research aircraft during an extended field campaign over the Atlantic ocean in support of the Lidar In-space Technology Experiment (LITE) in September of 1994. The 10 meter wind speed derived from the scatterometers and the lidar-radiometer inferred near-surface moisture are used to obtain an estimate of the surface flux of moisture via bulk aerodynamic formulae. The results are compared with the Special Sensor Microwave Imager (SSM/I) daily average latent heat flux and show reasonable agreement. However, the SSM/I values are biased high by about 30 W/sq m. In addition, the MABL height, entrainment zone thickness and integrated lidar backscatter intensity are computed from the lidar data and compared with the magnitude of the surface fluxes. The results show that the surface latent heat flux is most strongly correlated with entrainment zone top, bottom and the integrated MABL lidar backscatter, with corresponding correlation coefficients of 0.62, 0.67 and 0.61, respectively.

  10. Injection molding as a one-step process for the direct production of pharmaceutical dosage forms from primary powders.

    Science.gov (United States)

    Eggenreich, K; Windhab, S; Schrank, S; Treffer, D; Juster, H; Steinbichler, G; Laske, S; Koscher, G; Roblegg, E; Khinast, J G

    2016-05-30

    The objective of the present study was to develop a one-step process for the production of tablets directly from primary powder by means of injection molding (IM), to create solid-dispersion based tablets. Fenofibrate was used as the model API, a polyvinyl caprolactame-polyvinyl acetate-polyethylene glycol graft co-polymer served as a matrix system. Formulations were injection-molded into tablets using state-of-the-art IM equipment. The resulting tablets were physico-chemically characterized and the drug release kinetics and mechanism were determined. Comparison tablets were produced, either directly from powder or from pre-processed pellets prepared via hot melt extrusion (HME). The content of the model drug in the formulations was 10% (w/w), 20% (w/w) and 30% (w/w), respectively. After 120min, both powder-based and pellet-based injection-molded tablets exhibited a drug release of 60% independent of the processing route. Content uniformity analysis demonstrated that the model drug was homogeneously distributed. Moreover, analysis of single dose uniformity also revealed geometric drug homogeneity between tablets of one shot. PMID:27012981

  11. Studies in atomic-fluorescence spectroscopy-V The fluorescence characteristics and determination of antimony.

    Science.gov (United States)

    Dagnall, R M; Thompson, K C; West, T S

    1967-10-01

    Atomic-fluorescence of antimony may be generated in an air-propane flame by nebulizing aqueous solutions of antimony salts whilst irradiating the flame by means of a microwave-excited electrode-less discharge tube operating at 30 W. The strongest fluorescence is exhibited by the (4)S(11 2 ) --> (4)P(1 3 ) 2311 A resonance line and weaker signals are observed at the 2068 and 2176 A resonance lines and at four intercombination lines, at 2598, 2671, 2770 and 2878 A. A process of thermally assisted direct-line fluorescence is postulated to account for the otherwise inexplicable intensity of the 2598 A line emission. Atomic-fluorescence spectroscopy at 2176 A permits the determination of antimony in the range 0.1-120 ppm with a detection limit of 0.05 ppm. With the same equipment and source, the range of measurement for atomic-absorption was 6-120 ppm and the detection limit was 1 ppm. No interferences were observed from 100-fold molar amounts of Cd, Co, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, NH(4), Pb and Zn or from arsenate, chloride, nitrate, phosphate and sulphate. PMID:18960212

  12. Purification of serratiopeptidase from Serratia marcescens NRRL B 23112 using ultrasound assisted three phase partitioning.

    Science.gov (United States)

    Pakhale, Swapnil V; Bhagwat, Sunil S

    2016-07-01

    The ultrasound assisted three phase partitioning (UATPP) is a novel bioseparation method for separation and purification of biomolecules. In the present work, UATPP was investigated for the first time for purification of serratiopeptidase from Serratia marcescens NRRL B 23112. Effect of various process parameters such as ammonium sulphate saturation, t-butanol to crude extract ratio, pH, ultrasonic frequency, ultrasonic intensity, duty cycle and irradiation time were evaluated and optimized. The optimized conditions were found to be as follows: ammonium sulphate saturation 30% (w/v), pH 7.0, t-butanol to crude ratio 1:1 (v/v), ultrasound frequency 25 kHz, ultrasound intensity 0.05 W/cm(2), duty cycle 20% and irradiation time 5 min. The maximum purity and recovery obtained from UATPP was 9.4-fold and 96% respectively as compared to the three phase partitioning (TPP) (4.2-fo ld and 83%). Also the process time for UATPP was significantly reduced to 5 min from 1h as compared to TPP. The results indicate that, UATPP is an efficient technique for the purification of serratiopeptidase with maximum purity, recovery and reduced processing time. PMID:26964980

  13. [UV-induced DNA mutation of peach aphid].

    Science.gov (United States)

    Du, Erxia; Guo, Jianwen; Zhao, Huiyan

    2006-07-01

    By using PCR technique and microsatellite marks, this paper studied the DNA polymorphism of peach aphid (Myzus persicae) under UV-radiation. The fragments of three primers were amplified, and the gene diversity and the rate of loci polymorphisms of their genomic DNA, which could reflect the damage degree of DNA after UV-radiation, were measured. The results revealed that after treated with different radiation intensity (15, 30, 45 W) and duration (2, 4, 6 h) , the UV-induced DNA mutations were genetic and could be delivered to F2 generation. The mutations depended on the interaction of radiation intensity and duration. Variance analysis on the gene diversity and the rate of loci polymorphisms showed that there existed a significant difference between UV-treated and control groups, except the rate of loci polymorphisms under 2 h radiation. The average value of the control was higher than that of 2 h radiation treatment. According to the cluster analysis of the genetic distance, the aphids were divided into three groups, i. e., control group, 2 h (15, 30 W) treatment group, and the other, which was consistent with the result of variance analysis.

  14. Fermentative Polyhydroxybutyrate Production from a Novel Feedstock Derived from Bakery Waste

    Directory of Open Access Journals (Sweden)

    Daniel Pleissner

    2014-01-01

    Full Text Available In this study, Halomonas boliviensis was cultivated on bakery waste hydrolysate and seawater in batch and fed-batch cultures for polyhydroxybutyrate (PHB production. Results demonstrated that bakery waste hydrolysate and seawater could be efficiently utilized by Halomonas boliviensis while PHB contents between 10 and 30% (w/w were obtained. Furthermore, three methods for bakery waste hydrolysis were investigated for feedstock preparation. These include: (1 use of crude enzyme extracts from Aspergillus awamori, (2 Aspergillus awamori solid mashes, and (3 commercial glucoamylase. In the first method, the resultant free amino nitrogen (FAN concentration in hydrolysates was 150 and 250 mg L−1 after 20 hours at enzyme-to-solid ratios of 6.9 and 13.1 U g−1, respectively. In both cases, the final glucose concentration was around 130–150 g L−1. In the second method, the resultant FAN and glucose concentrations were 250 mg L−1 and 150 g L−1, respectively. In the third method, highest glucose and lowest FAN concentrations of 170–200 g L−1 and 100 mg L−1, respectively, were obtained in hydrolysates after only 5 hours. The present work has generated promising information contributing to the sustainable production of bioplastic using bakery waste hydrolysate.

  15. High-performance oscillators employing adaptive optics comprised of discrete elements

    Science.gov (United States)

    Jackel, Steven M.; Moshe, Inon; Lavi, Raphael

    1999-05-01

    Flashlamp pumped oscillators utilizing Nd:Cr:GSGG or Nd:YAG rods were stabilized against varying levels of thermal focusing by use of a Variable Radius Mirror (VRM). In its simplest form, the VRM consisted of a lens followed by a concave mirror. Separation of the two elements controlled the radius of curvature of the reflected phase front. Addition of a concave-convex variable-separation cylindrical lens pair, allowed astigmatism to be corrected. These distributed optical elements together with a computer controlled servo system formed an adaptive optic capable of correcting the varying thermal focusing and astigmatism encountered in a Nd:YAG confocal unstable resonator (0 - 30 W) and in Nd:Cr:GSGG stable (hemispherical or concave- convex) resonators so that high beam quality could be maintained over the entire operating range. By utilizing resonators designed to eliminate birefringence losses, high efficiency could also be maintained. The ability to eliminate thermally induced losses in GSGG allows operating power to be increased into the range where thermal fracture is a factor. We present some results on the effect of surface finish (fine grind, grooves, chemical etch strengthening) on fracture limit and high gain operation.

  16. Feasibility of computed tomography based thermometry during interstitial laser heating in bovine liver

    International Nuclear Information System (INIS)

    To assess the feasibility of computed tomography (CT) based thermometry during interstitial laser heating in the bovine liver. Four freshly exercised cylindrical blocks of bovine tissue were heated using a continuous laser of Nd:YAG (wavelength: 1064 nm, active length: 30 mm, power: 10-30 W). All tissues were imaged at least once before and 7 times during laser heating using CT and temperatures were simultaneously measured with 5 calibrated thermal sensors. The dependency of the average CT numbers as a function of temperature was analysed with regression analysis and a CT thermal sensitivity was derived. During laser heating, the growing hypodense area was observed around the laser source and that area showed an increase as a function of time. The formation of hypodense area was caused by declining in CT numbers at increasing temperatures. The regression analysis showed an inverse linear dependency between temperature and average CT number with -0.65 ± 0.048 HU/ C (R2 = 0.75) for the range of 18-85 C in bovine liver. The non-invasive CT based thermometry during interstitial laser heating is feasible in the bovine liver. CT based thermometry could be further developed and may be of potential use during clinical LITT of the liver. (orig.)

  17. Recrystallization characteristics of high hydrostatic pressure gelatinized normal and waxy corn starch.

    Science.gov (United States)

    Li, Wenhao; Tian, Xiaoling; Wang, Peng; Saleh, Ahmed S M; Luo, Qingui; Zheng, Jianmei; Ouyang, Shaohui; Zhang, Guoquan

    2016-02-01

    High hydrostatic pressure (HHP) can lead to starch gelatinization at room temperature, while the retrogradation mechanism of HHP gelatinized starch is not well known. HHP gelatinized normal and waxy corn starches were stored at room temperature for 192 h in order to investigate the retrogradation characteristics. The scanning electron microscopy (SEM), polarised light microscopy and differential scanning calorimetric (DSC) analysis showed that the pressurization of normal and waxy corn starch suspensions with concentration of 30% (w/v) at 600 MPa for 15 min resulted in a complete gelatinization. In addition, the pressure-gelatinized normal and waxy corn starch gels were stored and subjected to X-ray diffraction (XRD) analysis, resistant starch content determination, swelling power and pasting behavior. The retrograded normal maize and waxy maize starch showed a substantial loss of A-type crystallinity. Both pressure-gelatinized normal and waxy corn starches showed an increase in resistant starch content and relative crystallinity degree with the increase of storage time. In addition, restricted starch swelling power and lower pasting viscosities were observed for these two retrograded starches. The amylose molecule within starch granules has been regarded as the main factor to affect the structural and physicochemical properties during the retrogradation process of HHP-gelatinized starch granules. PMID:26642841

  18. Measurement of the cross-section ratio sigma_{psi(2S)}/sigma_{J/psi(1S)} in deep inelastic exclusive ep scattering at HERA

    CERN Document Server

    Abramowicz, H; Adamczyk, L; Adamus, M; Antonelli, S; Aushev, V; Aushev, Y; Behnke, O; Behrens, U; Bertolin, A; Bloch, I; Boos, E G; Borras, K; Brock, I; Brook, N H; Brugnera, R; Bruni, A; Bussey, P J; Caldwell, A; Capua, M; Catterall, C D; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cooper-Sarkar, A M; Corradi, M; Corriveau, F; Dementiev, R K; Devenish, R C E; Dolinska, G; Dusini, S; Figiel, J; Foster, B; Gach, G; Gallo, E; Garfagnini, A; Geiser, A; Gizhko, A; Gladilin, L K; Golubkov, Yu A; Grebenyuk, J; Gregor, I; Grzelak, G; Gueta, O; Guzik, M; Hain, W; Hochman, D; Hori, R; Ibrahim, Z A; Iga, Y; Ishitsuka, M; Iudin, A; Januschek, F; Jomhari, N Z; Kadenko, I; Kananov, S; Karshon, U; Kaur, M; Kaur, P; Kisielewska, D; Klanner, R; Klein, U; Kondrashova, N; Kononenko, O; Korol, Ie; Korzhavina, I A; Kotański, A; Kötz, U; Kovalchuk, N; Kowalski, H; Krupa, B; Kuprash, O; Kuze, M; Levchenko, B B; Levy, A; Libov, V; Limentani, S; Lisovyi, M; Lobodzinska, E; Löhr, B; Lohrmann, E; Longhin, A; Lontkovskyi, D; Lukina, O Yu; Makarenko, I; Malka, J; Mergelmeyer, S; Idris, F Mohamad; Nasir, N Mohammad; Myronenko, V; Nagano, K; Nobe, T; Notz, D; Nowak, R J; Onishchuk, Yu; Paul, E; Perlański, W; Pokrovskiy, N S; Przybycień, M; Roloff, P; Rubinsky, I; Ruspa, M; Saxon, D H; Schioppa, M; Schmidke, W B; Schneekloth, U; Schörner-Sadenius, T; Shcheglova, L M; Shevchenko, R; Shkola, O; Shyrma, Yu; Singh, I; Skillicorn, I O; Słomiński, W; Solano, A; Stanco, L; Stefaniuk, N; Stern, A; Stopa, P; Sztuk-Dambietz, J; Szuba, D; Szuba, J; Tassi, E; Tokushuku, K; Tomaszewska, J; Trofymov, A; Tsurugai, T; Turcato, M; Turkot, O; Tymieniecka, T; Verbytskyi, A; Viazlo, O; Walczak, R; Abdullah, W A T Wan; Wichmann, K; Wing, M; Wolf, G; Yamada, S; Yamazaki, Y; Zakharchuk, N; Żarnecki, A F; Zawiejski, L; Zenaiev, O; Zhautykov, B O; Zhmak, N; Zotkin, D S

    2016-01-01

    The exclusive deep inelastic electroproduction of $\\psi(2S)$ and $J/\\psi(1S)$ at an $ep$ centre-of-mass energy of 317 GeV has been studied with the ZEUS detector at HERA in the kinematic range $2 < Q^2 < 80$ GeV$^2$, $30 < W < 210$ GeV and $|t| < 1$ GeV$^2$, where $Q^2$ is the photon virtuality, $W$ is the photon-proton centre-of-mass energy and $t$ is the squared four-momentum transfer at the proton vertex. The data for $2 < Q^2 < 5$ GeV$^2$ were taken in the HERA I running period and correspond to an integrated luminosity of 114 pb$^{-1}$. The data for $5 < Q^2 < 80$ GeV$^2$ are from both HERA I and HERA II periods and correspond to an integrated luminosity of 468 pb$^{-1}$. The decay modes analysed were $\\mu^+\\mu^-$ and $J/\\psi(1S) \\pi^+\\pi^-$ for the $\\psi(2S)$ and $\\mu^+\\mu^-$ for the $J/\\psi(1S)$. The cross-section ratio $\\sigma_{\\psi(2S)}/\\sigma_{J/\\psi(1S)}$ has been measured as a function of $Q^2, W$ and $t$. The results are compared to predictions of QCD-inspired models of...

  19. Measurement of the cross-section ratio sigma_{psi(2S)}/sigma_{J/psi(1S)} in deep inelastic exclusive ep scattering at HERA

    CERN Document Server

    Abramowicz, H; Adamczyk, L; Adamus, M; Antonelli, S; Aushev, V; Aushev, Y; Behnke, O; Behrens, U; Bertolin, A; Bloch, I; Boos, E G; Borras, K; Brock, I; Brook, N H; Brugnera, R; Bruni, A; Bussey, P J; Caldwell, A; Capua, M; Catterall, C D; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cooper-Sarkar, A M; Corradi, M; Corriveau, F; Dementiev, R K; Devenish, R C E; Dolinska, G; Dusini, S; Figiel, J; Foster, B; Gach, G; Gallo, E; Garfagnini, A; Geiser, A; Gizhko, A; Gladilin, L K; Golubkov, Yu A; Grebenyuk, J; Gregor, I; Grzelak, G; Gueta, O; Guzik, M; Hain, W; Hochman, D; Hori, R; Ibrahim, Z A; Iga, Y; Ishitsuka, M; Iudin, A; Januschek, F; Jomhari, N Z; Kadenko, I; Kananov, S; Karshon, U; Kaur, M; Kaur, P; Kisielewska, D; Klanner, R; Klein, U; Kondrashova, N; Kononenko, O; Korol, Ie; Korzhavina, I A; Kotański, A; Kötz, U; Kovalchuk, N; Kowalski, H; Krupa, B; Kuprash, O; Kuze, M; Levchenko, B B; Levy, A; Libov, V; Limentani, S; Lisovyi, M; Lobodzinska, E; Löhr, B; Lohrmann, E; Longhin, A; Lontkovskyi, D; Lukina, O Yu; Makarenko, I; Malka, J; Mergelmeyer, S; Idris, F Mohamad; Nasir, N Mohammad; Myronenko, V; Nagano, K; Nobe, T; Notz, D; Nowak, R J; Onishchuk, Yu; Paul, E; Perlański, W; Pokrovskiy, N S; Przybycień, M; Roloff, P; Rubinsky, I; Ruspa, M; Saxon, D H; Schioppa, M; Schmidke, W B; Schneekloth, U; Schörner-Sadenius, T; Shcheglova, L M; Shevchenko, R; Shkola, O; Shyrma, Yu; Singh, I; Skillicorn, I O; Słomiński, W; Solano, A; Stanco, L; Stefaniuk, N; Stern, A; Stopa, P; Sztuk-Dambietz, J; Szuba, D; Szuba, J; Tassi, E; Tokushuku, K; Tomaszewska, J; Trofymov, A; Tsurugai, T; Turcato, M; Turkot, O; Tymieniecka, T; Verbytskyi, A; Viazlo, O; Walczak, R; Abdullah, W A T Wan; Wichmann, K; Wing, M; Wolf, G; Yamada, S; Yamazaki, Y; Zakharchuk, N; Żarnecki, A F; Zawiejski, L; Zenaiev, O; Zhautykov, B O; Zhmak, N; Zotkin, D S

    2016-01-01

    The exclusive deep inelastic electroproduction of $\\psi(2S)$ and $J/\\psi(1S)$ at an $ep$ centre-of-mass energy of 317 GeV has been studied with the ZEUS detector at HERA in the kinematic range $2 < Q^2 < 80$ GeV$^2$, $30 < W < 210$ GeV and $|t| < 1$ GeV$^2$, where $Q^2$ is the photon virtuality, $W$ is the photon-proton centre-of-mass energy and $t$ is the squared four-momentum transfer at the proton vertex. The data for $2 < Q^2 < 5$ GeV$^2$ were taken in the HERA I running period and correspond to an integrated luminosity of 114 pb$^{-1}$. The data for $5 < Q^2 < 80$ GeV$^2$ are from both HERA I and HERA II periods and correspond to an integrated luminosity of 468 pb$^{-1}$. The decay modes analysed were $\\mu^+\\mu^-$ and $J/\\psi(1S) \\,\\pi^+\\pi^-$ for the $\\psi(2S)$ and $\\mu^+\\mu^-$ for the $J/\\psi(1S)$. The cross-section ratio $\\sigma_{\\psi(2S)}/\\sigma_{J/\\psi(1S)}$ has been measured as a function of $Q^2, W$ and $t$. The results are compared to predictions of QCD-inspired models ...

  20. A plasma polymerization technique to overcome cerebrospinal fluid shunt infections

    Energy Technology Data Exchange (ETDEWEB)

    Coekeliler, D [Plasma Aided Bioengineering and Biotechnology Research Laboratory, Engineering Faculty, Hacettepe University, 06532, Ankara (Turkey); Caner, H [Department of Neurosurgery, School of Medicine, Baskent University, 06610, Ankara (Turkey); Zemek, J [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 53, Prague, Czech Republic (Czech Republic); Choukourov, A [Department of Macromolecular Physics, Charles University, V Holesovickach 2, 18000 Prague (Czech Republic); Biederman, H [Department of Macromolecular Physics, Charles University, V Holesovickach 2, 18000 Prague (Czech Republic); Mutlu, M [Plasma Aided Bioengineering and Biotechnology Research Laboratory, Engineering Faculty, Hacettepe University, 06532, Ankara (Turkey)

    2007-03-01

    Prosthetic devices, mainly shunts, are frequently used for temporary or permanent drainage of cerebrospinal fluid. The pathogenesis of shunt infection is a very important problem in modern medicine and generally this is characterized by staphylococcal adhesion to the cerebrospinal fluid shunt surfaces. In this paper, the prevention of the attachment of test microorganism Staphylococcus epidermidis on the cerebrospinal fluid shunt surfaces by 2-hydroxyethylmethacrylate (HEMA) precursor modification in the plasma polymerization system, is reported. Different plasma polymerization conditions (RF discharge power 10-20-30 W, exposure time 5-10-15 min) were employed during the surface modification. The surface chemistry and topology of unmodified and modified shunts was characterized by x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Also, static contact angle measurements were performed to state the change of surface hydrophilicity. All samples were tested in vitro with Staphylococcus epidermidis. A plasma-polymerized HEMA film (PP HEMA) was found to be an alternative simple method to decrease the microorganism attachment and create bacterial anti-fouling surfaces. The attachment of the model microorganism Staphylococcus epidermidis on the shunt surface modified by PP HEMA at 20 W and 15 min was reduced 62.3% if compared to the unmodified control surface of the shunt.