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Sample records for sub-5 fs laser

  1. All-solid-state cavity-dumped sub-5-fs laser

    NARCIS (Netherlands)

    Baltuska, A.; Wei, Z; Pshenichnikov, M.S; Wiersma, D. A.; Szipocs, R.

    We discuss in detail a compact all-solid-state laser delivering sub-5-fs, 2-MW pulses at repetition rates up to 1 MHz. The shortest pulse generated thus far measures only 4.6 fs. The laser system employed is based on a cavity-dumped Ti:sapphire oscillator whose output is chirped in a single-mode

  2. Ultrafast spectroscopy of coherent phonon in carbon nanotubes using sub-5-fs visible pulses

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Takayoshi [Advanced Ultrafast Laser Research Center, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585 (Japan); JST, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 Japan (Japan); Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871, Japan kobayashi@ils.uec.ac.jp (Japan)

    2016-02-01

    In the last two decades, nano materials are attracting many scientists’ interest for both basic and application viewpoints. In order to understand the properties of nano systems it is needed to understand the dynamic properties which control the specific properties of the systems. All the primary processes in nano systems are taking place in femtosecond regime. Our group has been able to stably generate visible to near-infrared sub-5-fs laser pulses using a noncollinear optical parametric amplifier (NOPA) by the combination of various novel techniques including non-collinear optical parametric amplifier, pulse compression by a prism pair and grating pair. We apply the sub-5-fs pulses to study real-time coherent phonon in a one-dimensional system of carbon nanotubes. We determine exciton-phonon coupling mechanisms by observing the breathing mode in semiconducting carbon nanotubes and show the effect of electronic transition affected by the vibrational mode.

  3. 40-fs hydrogen Raman laser

    Energy Technology Data Exchange (ETDEWEB)

    Didenko, N V; Konyashchenko, A V; Kostryukov, P V; Losev, L L; Pazyuk, V S [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Tenyakov, S Yu [Avesta Ltd., Troitsk, Moscow (Russian Federation); Molchanov, V Ya; Chizhikov, S I; Yushkov, K B [National University of Science and Technology ' MISIS' , Acoustooptical Research Center, Moscow (Russian Federation)

    2015-12-31

    40-fs first Stokes pulses at a wavelength of 1.2 μm were generated in a hydrogen SRS-converter pumped by orthogonally polarised double chirped pulses of a Ti : sapphire laser. To obtain a Stokes pulse close to a transform-limited one, a programmed acousto-optic dispersive delay line was placed between the master oscillator and regenerative amplifier. The energy efficiency of Stokes radiation conversion reached 22%. (lasers)

  4. Fs-laser processing of polydimethylsiloxane

    Energy Technology Data Exchange (ETDEWEB)

    Atanasov, Petar A., E-mail: paatanas@ie.bas.bg; Nedyalkov, Nikolay N. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Shose, Sofia 1784 (Bulgaria); Valova, Eugenia I.; Georgieva, Zhenya S.; Armyanov, Stefan A.; Kolev, Konstantin N. [Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 11, Sofia 1113 (Bulgaria); Amoruso, Salvatore; Wang, Xuan; Bruzzese, Ricardo [CNR-SPIN, Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Sawczak, Miroslaw; Śliwiński, Gerard [Photophysics Department, The Szewalski Institute, Polish Academy of Sciences, 14 Fiszera St, 80-231 Gdańsk (Poland)

    2014-07-14

    We present an experimental analysis on surface structuring of polydimethylsiloxane films with UV (263 nm) femtosecond laser pulses, in air. Laser processed areas are analyzed by optical microscopy, SEM, and μ-Raman spectroscopy. The laser-treated sample shows the formation of a randomly nanostructured surface morphology. μ-Raman spectra, carried out at both 514 and 785 nm excitation wavelengths, prior and after laser treatment allow evidencing the changes in the sample structure. The influence of the laser fluence on the surface morphology is studied. Finally, successful electro-less metallization of the laser-processed sample is achieved, even after several months from the laser-treatment contrary to previous observation with nanosecond pulses. Our findings address the effectiveness of fs-laser treatment and chemical metallization of polydimethylsiloxane films with perspective technological interest in micro-fabrication devices for MEMS and nano-electromechanical systems.

  5. Nonlinear light propagation in fs laser-written waveguide arrays

    Directory of Open Access Journals (Sweden)

    Szameit A.

    2013-11-01

    Full Text Available We report on recent achievements in the field of nonlinear light propagation in fs laser-written waveguide lattices. Particular emphasis is thereby given on discrete solitons in such systems.

  6. Fs level laser-to-RF synchronization at REGAE

    Science.gov (United States)

    Titberidze, M.; Felber, M.; Lamb, T.; Loch, R.; Sydlo, C.; Schlarb, H.

    2017-07-01

    The Relativistic Electron Gun for Atomic Exploration (REGAE) is a unique linear accelerator capable of producing ultrashort (∼ 10 fs) electron bunches for studying fast processes in matter by means of ultrafast electron diffraction (UED) experiments. Additionally, REGAE is suitable for upcoming external injection experiments for laser wakefield acceleration (LWFA). In order to carry out both mentioned experiments, it is crucial to achieve fs level stability in terms of laser-to-RF synchronization. In this paper we present an advanced laser- to-RF synchronization scheme based on integrated Mach-Zehnder Modulator (MZM). The setup demonstrated the Titanium Sapphire photoinjector laser synchronization with 11 fs (rms) precision in the bandwidth up to 100 kHz. Long term timing drift measurements showed unprecedented peak-to-peak stability of 31 fs (7 fs rms) over 43 hours of measurement time. In addition, AM-PM coefficient of the MZM based laser-to-RF synchronization setup has been evaluated and showed a factor of 10 improved performance compared to conventional direct conversion based laser synchronization setup.

  7. Fs-laser processing of medical grade polydimethylsiloxane (PDMS)

    Energy Technology Data Exchange (ETDEWEB)

    Atanasov, P.A., E-mail: paatanas@ie.bas.bg [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsaridradsko shose Blvd., Sofia 1784 (Bulgaria); Stankova, N.E.; Nedyalkov, N.N. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsaridradsko shose Blvd., Sofia 1784 (Bulgaria); Fukata, N. [International Centre for Materials for NanoArchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1Namiki, Tsukuba 305-0044 (Japan); Hirsch, D.; Rauschenbach, B. [Leibniz Institute of Surface Modification (IOM), Permoserstrasse 15, D-04318 Leipzig (Germany); Amoruso, S.; Wang, X. [Dipartimento di Fisica Università degli Studi di Napoli Federico II and CNR-SPIN, Complesso Universitario di Monte S.Angelo, Via Cintia, I-80126 Napoli (Italy); Kolev, K.N.; Valova, E.I.; Georgieva, J.S.; Armyanov, St.A. [Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 11, Sofia 1113 (Bulgaria)

    2016-06-30

    Highlights: • Fs-laser (263, 527 and 1055 nm) processing of PDMS-elastomer is studied. • High quality trenches are produced on the PDMS surface. • The trenches are analyzed by Laser Microscope and by μ-Raman spectrometry. • Selective Ni metallization of the trenches is accomplished via electro-less plating. • The metalized trenches are studied by SEM. - Abstract: Medical grade polydimethylsiloxane (PDMS) elastomer is a biomaterial widely used in medicine and high-tech devices, e.g. MEMS and NEMS. In this work, we report an experimental investigation on femtosecond laser processing of PDMS-elastomer with near infrared (NIR), visible (VIS) and ultraviolet (UV) pulses. High definition trenches are produced by varying processing parameters as laser wavelength, pulse duration, fluence, scanning speed and overlap of the subsequent pulses. The sample surface morphology and chemical composition are investigated by Laser Microscopy, SEM and Raman spectroscopy, addressing the effects of the various processing parameters through comparison with the native materials characteristics. For all the laser pulse wavelengths used, the produced tracks are successfully metalized with Ni via electro-less plating method. We observe a negligible influence of the time interval elapsed between laser treatment and metallization process. Our experimental findings suggest promising perspectives of femtosecond laser pulses in micro- and nano-fabrication of hi-tech PDMS devices.

  8. Plasmonic enhanced fs-laser optoporation of human melanoma cells

    Science.gov (United States)

    Baumgart, J.; Humbert, L.; St.-Louis Lalonde, B.; Lebrun, J.-J.; Meunier, M.

    2011-03-01

    In this paper, we present the results of in vitro gene transfer by plasmonic enhanced optoporation of human melanoma cells. The fs-laser based optoporation is a gentle and efficient method for transfection. An optimum perforation rate with efficient dye or DNA uptake and high viability of the cells (~90%) was found for different types of nanostructures, spherical and rod shaped. The technique offers a very high selectivity and the low damage induced to the cell leads to a high transfection efficiency. The cell selectivity of this technique on the one hand is realized by using bioconjugated nanostructures, that couple selectively to a special cell type, and on the other hand, the spatial selectivity is due to the fact that only irradiated cells are perforated. In many biological applications a virus free and efficient transfection method is needed, especially in terms of its use in vivo. In cancer cells, the aggressiveness of the cells is shown in the migration and invasion velocity. The laser based and nanostructure enhanced transfection of cells offers the possibility to directly compare the treated and untreated cells. The treatment for migration and invasion assays can be performed by laser-scraping and laser transfection, resulting in a fully non-contact and therefore sterile method where the shape and the size of the scrape is well defined and reproducible. The laser based scrape test therefore offers less uncertainty due to scrape variations, high transfection efficiency, as well as direct comparison of treated and control cells in the same dish.

  9. Spectral broadening of 25 fs laser pulses via self-phase modulation in a neon filled hollow core fibre

    Energy Technology Data Exchange (ETDEWEB)

    Weichert, Stefan

    2017-05-15

    The goal of this work was the realisation of a setup for spectral broadening and subsequent compression of 25 fs laser pulses provided by a commercial Ti:Sapphire based CPA laser system by means of the hollow core fibre chirped mirror compressor technique. For the spectral broadening a vessel containing the hollow waveguide filled with a noble gas serving as the nonlinear medium was set up and an alignment procedure was developed. Neon was chosen as the nonlinear medium for the self-phase modulation of the pulses. With this setup spectral broadening, sufficient for supporting sub 5 fs pulses, was observed. The spectra at different input energies and neon gas pressures were measured and the stability of these and their respective Fourier transform-limited pulses determined in order to find an operating point. For the compression of the self-phase modulated pulses a chirped mirror compressor was designed and set up, but not tested yet. The layout of a single-shot intensity autocorrelator capable of estimating the pulse duration of sub 10 fs pulses was given.

  10. Transient Newton rings in dielectrics upon fs laser ablation

    CERN Document Server

    Garcia-Lechuga, Mario; Hernandez-Rueda, Javier; Solis, Javier

    2014-01-01

    We report the appearance of transient Newton rings in dielectrics (sapphire and lead-oxide glass) during ablation with single fs laser pulses. Employing femtosecond microscopy with 800 nm excitation and 400 nm illumination, we observe a characteristic ring pattern that dynamically changes for increasing delay times between pump and probe pulse. Such transient Newton rings have been previously observed in metals and semiconductors at fluences above the ablation threshold and were related to optical interference of the probe beam reflected at the front surface of the ablating layer and at the interface of the non-ablating substrate. Yet, it had been generally assumed that this phenomenon cannot be (and has not been) observed in dielectrics due to the different ablation mechanism and optical properties of dielectrics. The fact that we are able to observe them has important consequences for the comprehension of the ablation mechanisms in dielectrics and provides a new method for investigating these mechanisms in ...

  11. Coatings synthesised by the pulsed laser ablation of a B{sub 4}C/W{sub 2}B{sub 5} ceramic composite

    Energy Technology Data Exchange (ETDEWEB)

    Tadadjeu Sokeng, I., E-mail: ifriky@tlabs.ac.za [Department of Electrical, Electronics and Computer Engineering, French South African Institute of Technology/Cape Peninsula University of Technology, Bellville campus, PO Box 1906, Bellville, 7530 (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Ngom, B.D. [Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Laboratoire de Photonique et de Nanofrabrication, Groupes de physique du Solide et Sciences des Matriaux (GPSSM), Facult des sciences et Techniques Universit Cheikh Anta Diop de Dakar (UCAD), B.P. 25114 Dakar, Fann Dakar (Senegal); Msimanga, M. [iThemba LABS Gauten, Private Bag 11, WITS 2050 Johannesburg (South Africa); Nuru, Z.Y.; Kotsedi, L.; Maaza, M. [Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Van Zyl, R.R. [Department of Electrical, Electronics and Computer Engineering, French South African Institute of Technology/Cape Peninsula University of Technology, Bellville campus, PO Box 1906, Bellville, 7530 (South Africa)

    2015-10-30

    A pellet of B{sub 4}C/W{sub 2}B{sub 5} ceramic composite was characterised and subjected to pulsed laser ablation for the deposition of coatings on corning glass substrates. We reports an attempt to produce coatings from B{sub 4}C/W{sub 2}B{sub 5} by pulsed laser deposition (PLD). The thermal, electric and mechanical properties of B{sub 4}C/W{sub 2}B{sub 5} suggest that coatings synthesised from this composite can be used for space applications. The samples were characterised using X-ray Diffraction, Atomic Force Microscopy and Heavy Ion Elastic Recoil Detection Analysis. The characterisation of the samples deposited on soda lime corning glass showed that the laser energy used in this PLD was enough to obtain non amorphous coatings formed by some alteration of the tungsten carbide crystal lattice at room temperature, and that there was no stoichiometry transfer as would be expected from PLD. The coating also showed space applicable features worth investigating. - Highlights: • B{sub 4}C/W{sub 2}B{sub 5} ceramic composite was ablated for deposition on corning glass subtrates. • Non-amorphous coating was obtained at room temperature. • There was no stoichiometry transfer as would be expected from Pulsed Laser Deposition.

  12. Background gas collisional effects on expanding fs and ns laser ablation plumes

    Science.gov (United States)

    Harilal, S. S.; Farid, N.; Freeman, J. R.; Diwakar, P. K.; LaHaye, N. L.; Hassanein, A.

    2014-10-01

    The collisional effects of a background gas on expanding ultrafast and short pulse laser ablation plumes were investigated by varying background pressure from vacuum to atmospheric pressure levels. For producing Cu ablation plumes, either 40 fs, 800 nm pulses from a Ti: Sapphire laser or 6 ns, 1,064 nm pulses from a Nd:YAG laser were used. The role of background pressure on plume hydrodynamics, spectral emission features, absolute line intensities, signal to background ratios and ablation craters was studied. Though the signal intensities were found to be maximum near to atmospheric pressure levels, the optimum signal to background ratios are observed ~20-50 Torr for both ns and fs laser ablation plumes. The differences in laser-target and laser-plasma couplings between ns and fs lasers were found to be more engraved in the crater morphologies and plasma hydrodynamic expansion features.

  13. Application of V{sub 2}O{sub 5} thin films deposited by laser ablation in micron batteries of solid state; Aplicacion de peliculas delgadas de V{sub 2}O{sub 5} depositadas por ablacion laser en micro-baterias de estado solido

    Energy Technology Data Exchange (ETDEWEB)

    Escobar A, L.; Camps, E.; Haro P, E.; Camacho L, M.A.; Julien, C. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2001-07-01

    The obtained results from synthesizing V{sub 2}O{sub 5} thin films by laser ablation are presented. Depending on the deposit conditions V{sub 2}O{sub 5} thin films have been grown as amorphous as a crystalline ones with preferential orientation. The results of the electrochemical characterization of one of the synthesized layers are presented when being manufactured joint with it a micron battery. (Author)

  14. Black phosphorus mode-locked sub-100 fs bulk laser based on heterostructured Yb composite crystal

    Science.gov (United States)

    Lou, Fei; Zhang, Baitao; Sun, Shijia; Hu, Chen; Lin, Zhoubin; Jiang, Jieyu; Zhang, Shuaiyi; Wang, Xia; Teng, Bing; He, Jingliang

    2018-01-01

    A physically combined heterostructured (PCH) Yb:KGW/Yb:SYB crystal is used to demonstrate a black phosphorus (BP) mode-locked sub-100 fs bulk laser. Near-transform-limited 75 fs pulses are yielded at 1054.6 nm with an output power of 1.03 W, corresponding to an optical-to-optical efficiency of 10%. This is the first implementation of the PCH concept into a mode-locked Yb-crystal laser to the best of our knowledge. The results not only illustrate the potential of the PCH Yb-crystal as an ideal candidate for realizing ultrafast lasers, but also indicate that BP mode-locking is a very promising approach for generating sub-100 fs pulses from a laser oscillator.

  15. Structure and optical property changes of Nb{sub 2}O{sub 5} particles by Q-switched laser pulses in water

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Jing-Yi; Wu, Chao-Hsien; Zheng, Yuyuan; Shen, Pouyan [National Sun Yat-sen University, Department of Materials and Optoelectronic Science, Kaohsiung (China); Chen, Shuei-Yuan [I-Shou University, Department of Mechanical and Automation Engineering, Kaohsiung (China)

    2014-06-15

    Monoclinic H-type Nb{sub 2}O{sub 5} powders subjected to Q-switched laser pulses in water were characterized by X-ray/electron diffraction and optical spectroscopy to have a significant optical property change with accompanied transformation into orthorhombic T-, pseudohexagonal TT-type and an amorphous phase. The T-Nb{sub 2}O{sub 5} nanoparticles were (100), (010), (001) and (anti 201) faceted and commonly in oriented intergrowth with TT-type or amorphized domains retaining the polymerized block units of the relic H-type. Such multiple-phase nanoparticles were hydrogenated and densified to modify Raman and FTIR bands and to show visible absorptions corresponding to a broad minimum band gap of 2.3-2.8 eV for potential opto-catalytic and electrochromic applications. (orig.)

  16. Sapphire capillaries for laser-driven wakefield acceleration in plasma. Fs-laser micromachining and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Schwinkendorf, Jan-Patrick

    2012-08-15

    Plasma wakefields are a promising approach for the acceleration of electrons with ultrahigh (10 to 100 GV/m) electric fields. Nowadays, high-intensity laser pulses are routinely utilized to excite these large-amplitude plasma waves. However, several detrimental effects such as laser diffraction, electron-wake dephasing and laser depletion may terminate the acceleration process. Two of these phenomena can be mitigated or avoided by the application of capillary waveguides, e.g. fabricated out of sapphire for longevity. Capillaries may compensate for laser diffraction like a fiber and allow for the creation of tapered gas-density profiles working against the dephasing between the accelerating wave and the particles. Additionally, they offer the possibility of controlled particle injection. This thesis is reporting on the set up of a laser for fs-micromachining of capillaries of almost arbitrary shapes and a test stand for density-profile characterization. These devices will permit the creation of tailored gas-density profiles for controlled electron injection and acceleration inside plasma.

  17. Mode-locked sub 200 fs laser pulses from an Er-Yb-Ce ZBLAN waveguide laser

    Science.gov (United States)

    Lancaster, David G.; Khurmi, Champak; Bourbeau-Hebert, Nicolas; Genest, Jerome; Chen, George; Zhang, Wenqi; Afshar, Shahraam; Monro, Tanya M.

    2017-02-01

    Passively mode-locked sub 200 fs pulses are generated from Er-Yb co-doped ZBLAN waveguide laser using a semiconductor saturable absorber mirror repetition rates of up to 533 MHz. At 156 MHz and 1556 nm central wavelength, the chip laser operates with a broad 25 nm bandwidth. The waveguides were written in the Er-Yb co-doped ZBLAN glass by using ultrafast laser inscription.

  18. Transport mean free path in K{sub 5}Bi{sub 1-x}Nd{sub x}(MoO{sub 4}){sub 4} laser crystal powders

    Energy Technology Data Exchange (ETDEWEB)

    Illarramendi, M A [Departamento de FIsica Aplicada I, Escuela Tecnica Superior de IngenierIa, Universidad del PaIs Vasco, Alda. Urquijo s/n, 48013 Bilbao (Spain); Aramburu, I [Departamento de FIsica Aplicada I, Escuela Tecnica Superior de IngenierIa, Universidad del PaIs Vasco, Alda. Urquijo s/n, 48013 Bilbao (Spain); Fernandez, J [Departamento de FIsica Aplicada I, Escuela Tecnica Superior de IngenierIa, Universidad del PaIs Vasco, Alda. Urquijo s/n, 48013 Bilbao (Spain); Balda, R [Departamento de FIsica Aplicada I, Escuela Tecnica Superior de IngenierIa, Universidad del PaIs Vasco, Alda. Urquijo s/n, 48013 Bilbao (Spain); Al-Saleh, M [Departamento de FIsica Aplicada I, Escuela Tecnica Superior de IngenierIa, Universidad del PaIs Vasco, Alda. Urquijo s/n, 48013 Bilbao (Spain)

    2007-01-24

    In this work, we calculate in two different ways the transport mean free paths in K{sub 5}Bi{sub 1-x}Nd{sub x}(MoO{sub 4}){sub 4} (x = 0.05, 0.2, 1) laser crystal powders by using the diffuse spectral reflectance and transmittance of the powders and the absorption coefficient of the crystal materials. The theoretical calculations have been made by assuming a diffusive propagation of light in these materials. Similar results have been obtained from both methods.

  19. Fs-laser ablation of teeth is temperature limited and provides information about the ablated components.

    Science.gov (United States)

    de Menezes, Rebeca Ferraz; Harvey, Catherine Malinda; de Martínez Gerbi, Marleny Elizabeth Márquez; Smith, Zachary J; Smith, Dan; Ivaldi, Juan C; Phillips, Alton; Chan, James W; Wachsmann-Hogiu, Sebastian

    2017-10-01

    The goal of this work is to investigate the thermal effects of femtosecond laser (fs-laser) ablation for the removal of carious dental tissue. Additional studies identify different tooth tissues through femtosecond laser induced breakdown spectroscopy (fsLIBS) for the development of a feedback loop that could be utilized during ablation in a clinical setting. Scanning Election Microscope (SEM) images reveal that minimal morphological damages are incurred at repetition rates below the carbonization threshold of each tooth tissue. Thermal studies measure the temperature distribution and temperature decay during laser ablation and after laser cessation, and demonstrate that repetition rates at or below 10kHz with a laser fluence of 40 J/cm(2) would inflict minimal thermal damage on the surrounding nerve tissues and provide acceptable clinical removal rates. Spectral analysis of the different tooth tissues is also conducted and differences between the visible wavelength fsLIBS spectra are evident, though more robust classification studies are needed for clinical translation. These results have initiated a set of precautionary recommendations that would enable the clinician to utilize femtosecond laser ablation for the removal of carious lesions while ensuring that the solidity and utility of the tooth remain intact. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. New class of compact diode pumped sub 10 fs lasers for biomedical applications

    DEFF Research Database (Denmark)

    Le, T.; Mueller, A.; Sumpf, B.

    2016-01-01

    Diode-pumping Ti: sapphire lasers promises a new approach to low-cost femtosecond light sources. Thus in recent years much effort has been taken just to overcome the quite low power and low beam qualities of available green diodes to obtain output powers of several hundred milliwatts from a fs-la...

  1. Passively mode-locked glass waveguide laser with 14-fs timing jitter.

    Science.gov (United States)

    Schlager, John B; Callicoatt, Berton E; Mirin, Richard P; Sanford, Norman A; Jones, David J; Ye, Jun

    2003-12-01

    Ultralow jitter pulse trains are produced from a passively mode-locked, erbium/ytterbium co-doped, planar waveguide laser by use of high-bandwidth feedback control acting on the physical cavity length and optical pump power. Synchronization of a 750-MHz, fundamentally mode-locked laser to an external clock signal yields an ultralow, root-mean-square relative timing jitter of 14.4 fs integrated from 10 Hz to the Nyquist frequency of 375 MHz.

  2. Structural and mechanical modifications induced on Cu{sub 47.5}Zr{sub 47.5}Al{sub 5} metallic glass by surface laser treatments

    Energy Technology Data Exchange (ETDEWEB)

    Fornell, J., E-mail: jordina.fornell@uab.cat [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain); Pellicer, E. [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain); Garcia-Lecina, E., E-mail: egarcia@cidetec.es [Surfaces Division, IK4-CIDETEC, Parque Tecnológico de San Sebastián, 20009 Donostia (Spain); Nieto, D. [Surfaces Division, IK4-CIDETEC, Parque Tecnológico de San Sebastián, 20009 Donostia (Spain); Suriñach, S.; Baró, M.D. [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain); Sort, J. [Institució Catalana de Recerca i Estudis Avançats and Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain)

    2014-01-30

    We have investigated the effects of surface laser treatment (SLT) on the structure, mechanical properties and wettability of Cu{sub 47.5}Zr{sub 47.5}Al{sub 5} metallic glass alloy. SLT has been carried out at three different intensities with the aim of inducing variable surface damage and tuneable changes in the resulting properties. X-ray diffraction characterization and scanning electron microscopy observations reveal that the alloy laser treated at 28.5 A remains amorphous while the alloy treated at 29 A becomes partially crystalline (CuZr B2 phase). When the alloy is treated at 30 A, it is mainly composed of copper and zirconium oxides. Nanoindentation tests, carried out on-top of the as-cast and laser-treated surfaces, reveal that SLT at 28.5 A causes an increase in hardness, which can be attributed to annihilation of free volume (i.e. structural relaxation). Conversely, hardness values of the alloy laser-treated at 29 A are almost the same as those of the as-cast alloy. This could be ascribed to the counterbalance effect between the softer nature of the CuZr B2 phase and the harder nature of the remaining relaxed amorphous phase. Larger hardness values are observed for the alloy laser treated at 30 A as a result of oxide phase formation.

  3. High-power widely tunable sub-20 fs Gaussian laser pulses for ultrafast nonlinear spectroscopy.

    Science.gov (United States)

    Metzger, Bernd; Steinmann, Andy; Giessen, Harald

    2011-11-21

    We demonstrate the generation of widely tunable sub-20 fs Gaussian-shaped laser pulses using a grating-based 4-f pulse shaper and a liquid crystal spatial light modulator. Our pump source is an Yb:KGW solitary mode-locked oscillator at 44 MHz repetition rate which is coupled into a large mode area microstructured fiber to generate a broad spectrum from below 900 nm to above 1150 nm. These pulses are precompressed by a prism sequence and subsequently sent into the pulse shaper. We use the multiphoton intrapulse interference phase scan (MIIPS) for phase shaping and iterative amplitude optimization to achieve Gaussian-like tunable sub-20 fs pulses with output powers of up to 142 mW as well as nontunable pulses with 310 mW output power as short as 11.5 fs. © 2011 Optical Society of America

  4. Proton-induced nanorod melting in a coating obtained from the pulsed laser ablation of W{sub 2}B{sub 5}/B{sub 4}C

    Energy Technology Data Exchange (ETDEWEB)

    Tadadjeu Sokeng, I., E-mail: ifriky@tlabs.ac.za [Department of Electrical, Electronics and Computer Engineering, French South African Institute of Technology/Cape Peninsula University of Technology, Bellville Campus, PO Box 1906, Bellville 7530 (South Africa); Electron Microscopy Unit, University of the Western Cape, Private bag x17, Bellville 7535 (South Africa); Ngom, B.D. [Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Laboratoire de Photonique et de Nanofrabrication, Groupes de physique du Solide et Sciences des Matriaux (GPSSM), Facult des sciences et Techniques, Universit Cheikh Anta Diop de Dakar (UCAD), B.P. 25114 Dakar-Fann, Dakar (Senegal); Cummings, F. [Electron Microscopy Unit, University of the Western Cape, Private bag x17, Bellville 7535 (South Africa); Kotsedi, L. [Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Msimanga, M. [iThemba LABS Gauten, Private Bag 11, WITS 2050, Johannesburg (South Africa); Maaza, M. [Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); and others

    2015-02-01

    Highlights: • Coatings from ablated B{sub 4}C/W{sub 2}B{sub 5} were irradiated with 900 keV protons. • Nanorod clusters were observed to melt and disperse. • Uniformly shaped nanorods were observed to grow. • Lateral diffusion of energy and lateral dispersion of matter were observed. - Abstract: Coatings obtained from pulsed laser ablated W{sub 2}B{sub 5}/B{sub 4}C were irradiated with 900keV protons at fluences ranging from about 1×10{sup 15}protons/cm{sup 2} to about 4×10{sup 15}protons/cm{sup 2}. Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) were used to study the resulting structural effects. Clusters of nanorods were observed to disperse and reduce in number with increase in proton fluence. The atomic percentage of constituent elements were observed to vary with proton fluence, both within the nanorods and the film floor. Our results show that the structural effect of proton irradiation on the coating is lateral dispersion of matter.

  5. Note: 15-fs, 15-μJ green pulses from two-stage temporal compressor of ytterbium laser pulses.

    Science.gov (United States)

    Konyashchenko, A V; Kostryukov, P V; Losev, L L; Tenyakov, S Yu

    2012-10-01

    15-fs, 15-μJ light pulses at the central wavelength of 515 nm were generated by two-stage nonlinear compression of 300-fs, 150-μJ ytterbium laser pulses. The compression was based on the pulse spectrum broadening by self-phase modulation in gas filled capillary and second harmonic generation in crystal.

  6. Time resolved EUV pump-probe microscopy of fs-LASER induced nanostructure formation

    Science.gov (United States)

    Freiberger, R.; Hauck, J.; Reininghaus, M.; Wortmann, D.; Juschkin, L.

    2011-05-01

    We report on our efforts in design and construction of a compact Extreme Ultraviolet (EUV)-pump-probe microscope. The goal is the observation of formation of nanostructures, induced by a femtosecond (fs)-laser pulse. The unique interaction processes of fs-laser radiation with matter open up new markets in laser material processing and, therefore, are actively investigated in the last decade. The resulting "sub 100 nm"-structures offer vast potential benefits in photonics, biotechnology, tribological surface design, plasmonic applications and production of nanoparticles. Focused fs-laser radiation causes a local modification resulting in nanostructures of high precision and reproducibility. However the formation dynamics is not well understood. Research in this field requires high temporal and spatial resolution. A combination of fs-laser and EUV-microscope provides a tool for "in situ"-observation of the formation dynamics. As exemplary structures to be investigated, we use nanojets on thin gold films and periodic surface structures (ripples) on dielectrics. In the future, the EUV-pump-probe microscope can become a versatile tool to observe physical or biological processes. Microscopy using EUV-light is capable of detecting structures on a scale down to several tens of nanometers. For detailed investigations a compact EUV-microscope has been realized utilizing OVI Balmer-alpha radiation at 17.3 nm coming from a discharge produced oxygen plasma. As optical elements a grazing incidence elliptical collector and a zone plate with a width of outermost zone of 50 nm and a spectral filter to avoid chromatic aberrations are used. The detector is a fast gated microchannel plate with a pore size of 2 microns contacted by a low impedance transmission line. The expected spatial resolution of the setup is better than 100 nm and the time resolution is better than 1 ns. The newly developed EUV-microscope is a powerful tool for a wide field of investigations that need high time

  7. Yb{sup 3+}:Sr{sub 5}(VO{sub 4}){sub 3}F: Crystal growth, spectroscopic characterization and laser development; Yb{sup 3+}:Sr{sub 5}(VO{sub 4}){sub 3}F: Crescimento, caracterizacao espectroscopica e desenvolvimento do laser

    Energy Technology Data Exchange (ETDEWEB)

    Bustamante, Andrea Nora Pino

    1999-07-01

    Crystal growth, spectroscopic characterization and laser development of Yb{sup 3+}:SVAP [Sr{sub 5}(VO{sub 4}){sub 3}F] was performed to demonstrate for the first time, operation of tunable laser emission centered at 1120 nm. Initially, SVAP crystals were grown with high dopant concentrations, up to 6.0 mol % of Yb{sub 2} O{sub 3} in the melt, in order to investigate the material for potential laser operation at a new laser wavelength. Additional research was performed to alleviate highly doped SVAP crystals of defects previously observed. Basic spectroscopic characterization including absorption and luminescent properties were measured to better understand the behavior of Yb{sup 3+} ions in SVAP. Based upon these studies, discussion of the 1120 nm laser transition is presented as it arises from a ground state vibrational level. Investigations of the charge compensation process and the optical parameters as a function of dopant concentration are also presented. The laser development of Yb{sup 3+}:SVAP included continuous and pulsed modes of operation of the 1044 nm and 1120 nm transitions. Initial laser action of the 1044 nm transition was achieved using a Yi: Saphire laser pump source in order to compare with previously results. Further development of a diode-pumped Yb{sup 3+}:SVAP laser system demonstrated continuously tunable laser operation from 1103 nm for the first time. The laser investigations also proved that this high gain media does provide continuous wave laser action at 1044 nm and 1120 simultaneously without significant gain depletion. (author)

  8. Plasmonic angular tunability of gold nanoparticles generated by fs laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Pace, M.L.; Guarnaccio, A.; Ranù, F. [CNR, ISM UOS Tito Scalo, Zona Industriale, Tito Scalo (PZ) 85050 (Italy); Trucchi, D. [CNR, ISM UOS Montelibretti, Via Salaria km 29.300, Monterotondo Scalo, (RM) 00015 (Italy); Orlando, S., E-mail: stefano.orlando@ism.cnr.it [CNR, ISM UOS Tito Scalo, Zona Industriale, Tito Scalo (PZ) 85050 (Italy); Mollica, D.; Parisi, G.P. [CNR, ISM UOS Tito Scalo, Zona Industriale, Tito Scalo (PZ) 85050 (Italy); Medici, L.; Lettino, A. [CNR, IMAA, Area della Ricerca di Potenza -Zona Industriale, Tito Scalo, (PZ) 85050 (Italy); De Bonis, A.; Teghil, R. [Dipart. di Scienze,Università della Basilicata, Viale dell’Ateneo Lucano 10, Potenza, 85100 (Italy); Santagata, A. [CNR, ISM UOS Tito Scalo, Zona Industriale, Tito Scalo (PZ) 85050 (Italy)

    2016-06-30

    Highlights: • fs pulsed laser ablation as a technique to produce nanoparticles. • Nanoparticle distribution as an evidence for plasmonic tunable resonances. • Correlation between angular distribution of deposited nanoparticles and specific plasmonic resonances. - Abstract: With the aim to study the influence of deposition parameters on the plasmonic properties of gold (Au) nanoparticles (NPs) deposited by ultra-short ablation, we have focused our attention in evaluating how their size distribution can be varied. In this work, the role played by the NPs’ angular distribution, agglomeration and growth is related to the resulting optical properties. UV–vis-NIR absorption spectra together with Scanning Electron Microscopy, Transmission Electron Microscopy and X-ray microdiffraction observations are presented in order to show how the angular distribution of fs laser ablation and deposition of Au NPs provides different plasmonic properties which can be beneficial for several aims, from optoelectronic to biosensor applications.

  9. 70-fs mode-locked erbium-doped fiber laser with topological insulator.

    Science.gov (United States)

    Liu, Wenjun; Pang, Lihui; Han, Hainian; Tian, Wenlong; Chen, Hao; Lei, Ming; Yan, Peiguang; Wei, Zhiyi

    2016-01-27

    Femtosecond optical pulses have applications in optical communication, astronomical frequency combs, and laser spectroscopy. Here, a hybrid mode-locked erbium-doped fiber (EDF) laser with topological insulator (TI) is proposed, for the first time to our best knowledge. The pulsed laser deposition (PLD) method is employed to fabricate the fiber-taper TI saturable absorber (TISA). By virtue of the fiber-taper TISA, the hybrid EDF laser is passively mode-locked using the nonlinear polarization evolution (NPE), and emits 70 fs pulses at 1542 nm, whose 3 dB spectral width is 63 nm with a repetition rate and transfer efficiency of 95.4 MHz and 14.12%, respectively. Our experiments indicate that the proposed hybrid mode-locked EDF lasers have better performance to achieve shorter pulses with higher power and lower mode-locking threshold in the future.

  10. 17-fs pulses from a self-mode-locked Ti:sapphire laser.

    Science.gov (United States)

    Huang, C P; Asaki, M T; Backus, S; Murnane, M M; Kapteyn, H C; Nathel, H

    1992-09-15

    We have generated sub-17-fs-duration pulses directly from a self-mode-locked Ti:sapphire laser. These pulses are near transform limited, with a wavelength centered at 817 nm, a pulse repetition rate of 80 MHz, and an average power of 500 mW. By minimizing the amount of material inside the laser cavity and choosing the correct glass for the intracavity prism pair, third-order dispersion in the laser can be significantly reduced compared with that in previous designs. Extracavity compensation for group-velocity dispersion in the output coupler and autocorrelator optics is necessary to measure this pulse width. To our knowledge this laser generates pulses substantially shorter than any other laser to date.

  11. Refractive index-modified structures in glass written by 266nm fs laser pulses.

    Science.gov (United States)

    Saliminia, Ali; Bérubé, Jean-Philippe; Vallée, Réal

    2012-12-03

    We demonstrate the inscription of embedded waveguides, anti-waveguides and Bragg gratings by use of intense femtosecond (fs) UV laser pulses at 266nm in pure fused silica, and for the first time, in bulk fused quartz and ZBLAN glasses. The magnitude of induced index changes, depends, besides pulse energy and translation speed, largely on writing depth and varies from ~10(-4) for smooth modifications to ~10(-3) for damaged structures. The obtained results are promising as they present the feasibility of fabrication of short (lasers operating at short wavelengths.

  12. Diode-pumped Kerr-lens mode-locked Yb: GSO laser generating 72 fs pulses

    Science.gov (United States)

    Tian, Wenlong; Wang, Zhaohua; Zhu, Jiangfeng; Zheng, Lihe; Xu, Xiaodong; Xu, Jun; Wei, Zhiyi

    2016-05-01

    The generation of 72 fs hyperbolic secant pulses centered at 1050 nm with 17.8 nm bandwidth from a diode pumped Kerr-lens mode-locked Yb: GSO laser is demonstrated. With the help of a semiconductor saturable absorber mirror, stable mode-locking with an average output power of 85 mW at a repetition rate of 113 MHz is realized. To the best of our knowledge, this is the first demonstration of Kerr-lens mode-locking in Yb: GSO laser.

  13. Diode-pumped Kerr-lens mode-locked Yb:LYSO laser with 61fs pulse duration.

    Science.gov (United States)

    Tian, Wenlong; Wang, Zhaohua; Wei, Long; Peng, Yingnan; Zhang, Jinwei; Zhu, Zheng; Zhu, Jiangfeng; Han, Hainian; Jia, Yulei; Zheng, Lihe; Xu, Jun; Wei, Zhiyi

    2014-08-11

    A stable diode pumped Kerr-lens mode-locked (KLM) Yb:LuYSiO5 (Yb:LYSO) laser of generating 61 fs pulses at a central wavelength of 1055.4 nm is experimentally demonstrated. This is, to the best of our knowledge, the first demonstration of femtosecond KLM operation in Yb:LYSO laser, and it is believed that 61 fs is the shortest pulse duration ever produced from an Yb-doped orthosilicate laser. The average output power of the mode-locked laser is 40 mW and the repetition rate is 113 MHz.

  14. Interaction Mechanisms of Cavitation Bubbles Induced by Spatially and Temporally Separated fs-Laser Pulses

    Science.gov (United States)

    Tinne, Nadine; Kaune, Brigitte; Krüger, Alexander; Ripken, Tammo

    2014-01-01

    The emerging use of femtosecond lasers with high repetition rates in the MHz regime together with limited scan speed implies possible mutual optical and dynamical interaction effects of the individual cutting spots. In order to get more insight into the dynamics a time-resolved photographic analysis of the interaction of cavitation bubbles is presented. Particularly, we investigated the influence of fs-laser pulses and their resulting bubble dynamics with various spatial as well as temporal separations. Different time courses of characteristic interaction effects between the cavitation bubbles were observed depending on pulse energy and spatio-temporal pulse separation. These ranged from merely no interaction to the phenomena of strong water jet formation. Afterwards, the mechanisms are discussed regarding their impact on the medical application of effective tissue cutting lateral to the laser beam direction with best possible axial precision: the mechanical forces of photodisruption as well as the occurring water jet should have low axial extend and a preferably lateral priority. Furthermore, the overall efficiency of energy conversion into controlled mechanical impact should be maximized compared to the transmitted pulse energy and unwanted long range mechanical side effects, e.g. shock waves, axial jet components. In conclusion, these experimental results are of great importance for the prospective optimization of the ophthalmic surgical process with high-repetition rate fs-lasers. PMID:25502697

  15. Interaction mechanisms of cavitation bubbles induced by spatially and temporally separated fs-laser pulses.

    Directory of Open Access Journals (Sweden)

    Nadine Tinne

    Full Text Available The emerging use of femtosecond lasers with high repetition rates in the MHz regime together with limited scan speed implies possible mutual optical and dynamical interaction effects of the individual cutting spots. In order to get more insight into the dynamics a time-resolved photographic analysis of the interaction of cavitation bubbles is presented. Particularly, we investigated the influence of fs-laser pulses and their resulting bubble dynamics with various spatial as well as temporal separations. Different time courses of characteristic interaction effects between the cavitation bubbles were observed depending on pulse energy and spatio-temporal pulse separation. These ranged from merely no interaction to the phenomena of strong water jet formation. Afterwards, the mechanisms are discussed regarding their impact on the medical application of effective tissue cutting lateral to the laser beam direction with best possible axial precision: the mechanical forces of photodisruption as well as the occurring water jet should have low axial extend and a preferably lateral priority. Furthermore, the overall efficiency of energy conversion into controlled mechanical impact should be maximized compared to the transmitted pulse energy and unwanted long range mechanical side effects, e.g. shock waves, axial jet components. In conclusion, these experimental results are of great importance for the prospective optimization of the ophthalmic surgical process with high-repetition rate fs-lasers.

  16. Polarisation-dependent generation of fs-laser induced periodic surface structures

    Science.gov (United States)

    Gräf, Stephan; Müller, Frank A.

    2015-03-01

    The formation of laser induced periodic surface structures (LIPPS) was investigated on polished stainless steel surfaces under irradiation with fs-laser pulses characterised by a pulse duration τ = 300 fs, a laser wavelength λ = 1025 nm, a repetition frequency frep = 250 Hz and a laser fluence F = 1 J/cm2. For this purpose line scans with a scanning velocity v = 0.5 mm/s were performed in air environment at normal incidence utilising a well-defined temporal control of the electrical field vector. The generated surface structures were characterised by optical microscopy, by scanning electron microscopy and by atomic force microscopy in combination with Fourier transformation. The results reveal the formation of a homogenous and highly periodic surface pattern of ripples with a period Λexp ≈ 925 nm aligned perpendicular to the incident electric field vector for static linear polarisation states. Utilising a motor-driven rotation device it was demonstrated that a continuously rotating electric field vector allows to transfer the originally well-ordered periodic ripples into tailored disordered surface structures that could be of particular interest for e.g. absorbing surfaces, plasmonic enhanced optoelectronic devices and biomedical applications.

  17. Interaction mechanisms of cavitation bubbles induced by spatially and temporally separated fs-laser pulses.

    Science.gov (United States)

    Tinne, Nadine; Kaune, Brigitte; Krüger, Alexander; Ripken, Tammo

    2014-01-01

    The emerging use of femtosecond lasers with high repetition rates in the MHz regime together with limited scan speed implies possible mutual optical and dynamical interaction effects of the individual cutting spots. In order to get more insight into the dynamics a time-resolved photographic analysis of the interaction of cavitation bubbles is presented. Particularly, we investigated the influence of fs-laser pulses and their resulting bubble dynamics with various spatial as well as temporal separations. Different time courses of characteristic interaction effects between the cavitation bubbles were observed depending on pulse energy and spatio-temporal pulse separation. These ranged from merely no interaction to the phenomena of strong water jet formation. Afterwards, the mechanisms are discussed regarding their impact on the medical application of effective tissue cutting lateral to the laser beam direction with best possible axial precision: the mechanical forces of photodisruption as well as the occurring water jet should have low axial extend and a preferably lateral priority. Furthermore, the overall efficiency of energy conversion into controlled mechanical impact should be maximized compared to the transmitted pulse energy and unwanted long range mechanical side effects, e.g. shock waves, axial jet components. In conclusion, these experimental results are of great importance for the prospective optimization of the ophthalmic surgical process with high-repetition rate fs-lasers.

  18. 152 fs nanotube-mode-locked thulium-doped all-fiber laser

    Science.gov (United States)

    Wang, Jinzhang; Liang, Xiaoyan; Hu, Guohua; Zheng, Zhijian; Lin, Shenghua; Ouyang, Deqin; Wu, Xu; Yan, Peiguang; Ruan, Shuangchen; Sun, Zhipei; Hasan, Tawfique

    2016-01-01

    Ultrafast fiber lasers with broad bandwidth and short pulse duration have a variety of applications, such as ultrafast time-resolved spectroscopy and supercontinuum generation. We report a simple and compact all-fiber thulium-doped femtosecond laser mode-locked by carbon nanotubes. The oscillator operates in slightly normal cavity dispersion at 0.055 ps2, and delivers 152 fs pulses with 52.8 nm bandwidth and 0.19 nJ pulse energy. This is the shortest pulse duration and the widest spectral width demonstrated from Tm-doped all-fiber lasers based on 1 or 2 dimensional nanomaterials, underscoring their growing potential as versatile saturable absorber materials. PMID:27374764

  19. Time-resolved microscopy of fs-laser-induced heat flows in glasses

    Science.gov (United States)

    Bonse, Jörn; Seuthe, Thomas; Grehn, Moritz; Eberstein, Markus; Rosenfeld, Arkadi; Mermillod-Blondin, Alexandre

    2018-01-01

    Time-resolved phase-contrast microscopy is employed to visualize spatio-temporal thermal transients induced by tight focusing of a single Ti:sapphire fs-laser pulse into a solid dielectric sample. This method relies on the coupling of the refractive index change and the sample temperature through the thermo-optic coefficient d n/d T. The thermal transients are studied on a timescale ranging from 10 ns up to 0.1 ms after laser excitation. Beyond providing direct insights into the laser-matter interaction, analyzing the results obtained also enables quantifying the local thermal diffusivity of the sample on a micrometer scale. Studies conducted in different solid dielectrics, namely amorphous fused silica (a-SiO2), a commercial borosilicate glass (BO33, Schott), and a custom alkaline earth silicate glass (NaSi66), illustrate the applicability of this approach to the investigation of various glassy materials.

  20. Production of high energy electrons by irradiation of fs-pulse laser on copper film

    Energy Technology Data Exchange (ETDEWEB)

    Oishi, Yuji; Nayuki, Takuya; Fujii, Takashi; Nemoto, Koshichi [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan); Kayoiji, Tsutomu [Tokyo Inst. of Technology, Interdisciplinary Graduate School of Science and Engineering, Yokohama, Kanagawa (Japan); Okano, Yasuaki; Hironaka, Yoichiro; Nakamura, Kazutaka G.; Kondo, Ken-ichi [Tokyo Inst. of Technology, Materials and Structures Laboratory, Yokohama, Kanagawa (Japan)

    2002-07-01

    Fast electrons with energy corresponding to the ponderomotive potential were produced by laser irradiation of 43-fs, 2.7 X 10{sup 18} W/cm{sup 2} on a 30 {mu}m thick copper target. The energy spectra of the electrons were directly measured using a magnetic spectrometer with an imaging plate. The typical temperature was 350 keV for irradiation at 15deg incidence angle. The energy spectra of high-energy photons, which were expected to be produced from the electrons, were also calculated. (author)

  1. Studies on perovskite film ablation and scribing with ns-, ps- and fs-laser pulses

    Science.gov (United States)

    Bayer, Lukas; Ye, Xinyuan; Lorenz, Pierre; Zimmer, Klaus

    2017-10-01

    Hybrid organic-inorganic perovskites attract much attention due to their exceptional optoelectronic properties, in particular for photovoltaic (PV) applications. The accurate, high-speed and reliable patterning of the PV films is required for perovskite solar modules fabrication. Laser scribing provides these characteristics needed for industrial fabrication processes. In this work, the laser ablation and scribing of perovskite layers (CH3NH3PbI3: MAPbI3) with different laser sources (ns-, ps-, fs-laser pulses with wavelengths of 248 nm to 2.5 µm) were systematically investigated. The perovskite material was irradiated from both the film side and the substrate (rear side) side to study and compare the particular processes. The patterning results of the perovskite film can be classified into (1) regular laser ablation, (2) thin-film delamination lift-off process, and (3) lift-off with thermal modifications. A particular process, the localised lift-off of single grains from the perovskite film, has been observed and is discussed in relation to the thin-film lift-off process. Ablation and ablation-related mechanisms provide good conditions for laser scribing of the perovskite layer required for module interconnection via P2.

  2. fs- and ns-laser processing of polydimethylsiloxane (PDMS) elastomer: Comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Stankova, N.E., E-mail: nestankova@yahoo.com [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Shose, Sofia 1784 (Bulgaria); Atanasov, P.A.; Nedyalkov, N.N.; Stoyanchov, T.R. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Shose, Sofia 1784 (Bulgaria); Kolev, K.N.; Valova, E.I.; Georgieva, J.S.; Armyanov, St.A. [Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 11, Sofia 1113 (Bulgaria); Amoruso, S.; Wang, X.; Bruzzese, R. [CNR-SPIN, Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Grochowska, K.; Śliwiński, G. [Photophysics Department, The Szewalski Institute, Polish Academy of Sciences, 14 Fiszera St., 80-231 Gdańsk (Poland); Baert, K.; Hubin, A. [Vrije Universiteit Brussels, Faculty of Engineering, Research group, SURF “Electrochemical and Surface Engineering” (Belgium); Delplancke, M.P.; Dille, J. [Université Libre de Bruxelles, Materials Engineering, Characterization, Synthesis and Recycling (Service 4MAT), Faculté des Sciences Appliquées, 1050 Brussels (Belgium)

    2015-05-01

    Highlights: • fs- and ns-laser (266 and 532 nm) processing of PDMS-elastomer, in air, is studied. • High definition tracks (on the PDMS-elastomer surface) for electrodes are produced. • Selective Pt or Ni metallization of the tracks is produced via electroless plating. • Irradiated and metallized tracks are characterized by μ-Raman spectrometry and SEM. • DC resistance of Pt and Ni tracks is always between 0.5 and 15 Ω/mm. - Abstract: Medical grade polydimethylsiloxane (PDMS) elastomer is a widely used biomaterial as encapsulation and/or as substrate insulator carrier for long term neural implants because of its remarkable properties. Femtosecond (λ = 263 and 527 nm) and nanosecond (266 and 532 nm) laser processing of PDMS-elastomer surface, in air, is investigated. The influence of different processing parameters, including laser wavelength, pulse duration, fluence, scanning speed and overlapping of the subsequent pulses, on the surface activation and the surface morphology are studied. High definition tracks and electrodes are produced. Remarkable alterations of the chemical composition and structural morphology of the ablated traces are observed in comparison with the native material. Raman spectra illustrate well-defined dependence of the chemical composition on the laser fluence, pulse duration, number of pulses and wavelength. An extra peak about ∼512–518 cm{sup −1}, assigned to crystalline silicon, is observed after ns- or visible fs-laser processing of the surface. In all cases, the intensities of Si−O−Si symmetric stretching at 488 cm{sup −1}, Si−CH{sub 3} symmetric rocking at 685 cm{sup −1}, Si−C symmetric stretching at 709 cm{sup −1}, CH{sub 3} asymmetric rocking + Si−C asymmetric stretching at 787 cm{sup −1}, and CH{sub 3} symmetric rocking at 859 cm{sup −1}, modes strongly decrease. The laser processed areas are also analyzed by SEM and optical microscopy. Selective Pt or Ni metallization of the laser processed

  3. More 3D PIC simulations on the smlwfa of 35fs class lasers

    Science.gov (United States)

    Mori, W. B.; Tsung, F. S.; Ren, C.; Adam, J. C.; Silva, L. O.; Fonseca, R. A.

    2002-11-01

    In the self-modulated laser wakefield regime a laser pulse several to many 2 π c/ ωp long breaks up via Raman scattering type instabilities producing large wakes. In some cases these wakes can trap background electrons generating a beam of accelerated electrons with a large energ spread. PIC simuations have shown that this process is highly sensitive to the laser intenisty, pulse length, and plasma density [K-C.Tzeng et al.PRL 76, 3332 (1996), K-C.Tzeng et al, PRL 79, 5258 (1997)]. There have been several recent experiments, e.g., V.Malka et al., Phys.Plasmas 8, 2605 (2001), in which 35fs laser pulses have been used. In this case the pulses are at most only a few 2 π c/ ωp even at the highest densities. We report here on our continuing PIC study using the code OSIRIS for parameters relevant to these experiments. We have found that the number of electrons and the maximum electron energy both decrease as the plasma density is raised, which is in agreement with the experimental results. We will also discuss the acceleration mechanism, the angular spread and the effects of raising the laser power. Work supported by DOE and NSF

  4. Analysis of optical side-effects of fs-laser therapy in human presbyopic lens simulated with modified contact lenses.

    Science.gov (United States)

    Peter, Monika; Kammel, Robert; Ackermann, Roland; Schramm, Stefan; Seifert, Bernd-Ulrich; Frey, Katharina; Blum, Marcus; Nolte, Stefan; Kunert, Kathleen S

    2012-12-01

    In a single-blinded study, optical side-effects of a potential femtosecond (fs)-laser therapy in presbyopic human lenses were tested. Simulation of this therapy was carried out by applying fs-laser patterns into standard contact lenses (CL). In the first part of the study, the influence of the numerical aperture on optical side-effects was investigated by comparing a typical fs-LASIK configuration to a fs-presbyopia treatment (n = 11). The second part focused on a possible improvement of visual performance by comparing a regular grid pattern to a randomly chosen spacing of the laser spots (n = 16). Visual acuity was measured with ETDRS charts, contrast sensitivity with F.A.C.T. charts and mesopic vision with Mesotest II. Forward scattered light was measured with the C-Quant (both instruments: Oculus Optikgeräte GmbH, Germany). A questionnaire detected subjective quality of vision. Differences between laser-treated and untreated CL and among the modifications were analyzed. The laser-treated and standard CL indicated no significant difference in visual acuity, contrast sensitivity and mesopic vision without glare. While wearing modified lenses with a regular grid, quality of vision decreased significantly by means of mesopic vision with glare and subjective straylight. These modifications also caused an impairment of subjective quality of vision. In contrast, there was no significant difference between the random pattern and standard CL. The increase of optical side-effects was reproducibly dependent on the geometry of the laser-structure. A randomized grid induced the least limitation. The study results are useful for planning possible laser-patterns in fs-laser therapy of the presbyopic lens.

  5. Coulomb explosion of H{sub 2} induced by a sub-10 fs intense laser pulse; Explosion coulombienne de H{sub 2} induite par une impulsion laser intense sub-10 fs

    Energy Technology Data Exchange (ETDEWEB)

    Saugout, S

    2006-12-15

    This work presents an experimental and theoretical study of the interaction of H2 with an intense sub-10 fs-laser pulse. The ejection of the two electrons of the molecule by the laser pulse leads to the fragmentation of the physical sys em in two protons. This process is called Coulomb Explosion. The electronic and nuclear dynamics can be analyzed by measuring the kinetic energy spectra as a function of different laser parameters. This dynamics is also analyzed through a non-perturbative, double active electron theoretical model, based on the resolution of the time dependent Schroedinger equation. In this model, the internuclear distance is treated as a quantum variable. The experimental and theoretical results enlight the translation of the kinetic energy spectra towards a higher energy when the pulse duration decreases. Experimentally, laser pulses from 40 to 10 fs were used and down to 1 fs using theoretical simulations. This study shows that, for laser pulses shorter than 4 fs, the carrier envelope phase becomes a crucial parameter. Furthermore, the molecular dynamics of H2 in intense laser field is sensitive to the peak intensity of the pulse. The experimental and theoretical results show that, as the intensity increases, the kinetic energy spectra are centered around a higher energy. In addition, the presence of two double ionization regimes is theoretically demonstrated for a pulse duration of 4 fs. The H{sub 2} molecule is also sensitive to the temporal shape of the laser pulse. This sensitivity allows for the detection of pre- or post-pulses by measuring the experimental kinetic energy spectra. Finally, the different double ionization processes are studied. The results show that the electron rescattering influences the femtosecond nuclear dynamics. (author)

  6. Generation of sub-100-fs pulses from a CW mode-locked chromium-doped forsterite laser

    Science.gov (United States)

    Seas, A.; Petricevic, V.; Alfano, R. R.

    1992-01-01

    Generation of femtosecond pulses from a continuous-wave mode-locked chromium-doped forsterite laser is reported. The forsterite laser was actively mode locked by using an acoustooptic modulator operating at 78 MHz with two Brewster high-dispersion glass prisms for intracavity chirp compensation. Transform-limited sub-100-fs pulses were routinely generated in the TEM(00) mode with 85 mW of continuous power (with 1 percent output coupler), tunable over 1230-1280 nm. The shortest pulses measured had a 60-fs pulse width.

  7. Low-loss flake-graphene saturable absorber mirror for laser mode-locking at sub-200-fs pulse duration

    CERN Document Server

    Cunning, B V; Kielpinski, D

    2011-01-01

    Saturable absorbers are a key component for mode-locking femtosecond lasers. Polymer films containing graphene flakes have recently been used in transmission as laser mode-lockers, but suffer from high nonsaturable loss, limiting their application in low-gain lasers. Here we present a saturable absorber mirror based on a film of pure graphene flakes. The device is used to mode lock an erbium-doped fiber laser, generating pulses with state-of-the-art, sub-200-fs duration. The laser characteristic indicate that the film exhibits low nonsaturable loss (13% per pass) and large absorption modulation depth (45% of low-power absorption).

  8. Femtosecond (FS) laser vision correction procedure for moderate to high myopia: a prospective study of ReLEx(®) flex and comparison with a retrospective study of FS-laser in situ keratomileusis

    DEFF Research Database (Denmark)

    Vestergaard, Anders; Ivarsen, Anders; Asp, Sven

    2013-01-01

    Purpose:  To present our initial clinical experience with ReLEx(®) flex (ReLEx) for moderate to high myopia. We compare efficacy, safety and corneal higher-order aberrations after ReLEx with femtosecond laser in situ keratomileusis (FS-LASIK). Methods:  Prospective study of ReLEx compared...

  9. Sub-100 fs single-walled carbon nanotube saturable absorber mode-locked Yb-laser operation near 1 microm.

    Science.gov (United States)

    Schmidt, Andreas; Rivier, Simon; Cho, Won Bae; Yim, Jong Hyuk; Choi, Sun Young; Lee, Soonil; Rotermund, Fabian; Rytz, Daniel; Steinmeyer, Günter; Petrov, Valentin; Griebner, Uwe

    2009-10-26

    Transmission- and reflection-type single-walled carbon nanotube saturable absorbers (SWCNT-SAs) were designed and fabricated for passive mode-locking of bulk lasers in the 1 microm spectral range. Mode-locked laser operation based on a diffusion-bonded Yb:KYW/KYW crystal was demonstrated, and pulses as short as 83 fs and 140 fs were achieved applying reflection-type and transmission-type SWCNT-SA, respectively. The nonlinear parameters of the absorbers were measured to be in close vicinity to those of a semiconductor saturable absorber mirror for the same wavelength range. Mode-locking performance with SWCNT-SAs and the SESAM was compared utilizing the same cavity, with the SESAM resulting in only slightly shorter pulses of 66 fs duration. The nearly identical performance indicates that well-optimized SWCNT-SAs can substitute SESAMs even in the 1 microm region.

  10. Evidence of the semiconductor-metal transition in V{sub 2}O{sub 5} thin films by the pulsed laser photoacoustic method

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Pacheco, A.; Acosta-Najarro, D. R.; Cruz-Manjarrez, H.; Rodriguez-Fernandez, L.; Pineda-Santamaria, J. C; Aguilar-Franco, M. [Instituto de Fisica-Universidad Nacional Autonoma de Mexico, Mexico DF (Mexico); Castaneda-Guzman, R. [Laboratorio de Fotofisica y Peliculas Delgadas, CCADET-UNAM, Mexico DF (Mexico)

    2013-05-14

    In this work, the pulsed photoacoustic technique was used to investigate the semiconductor-metal transition of thin vanadium pentoxide films (V{sub 2}O{sub 5}) under increasing temperature. The V{sub 2}O{sub 5} thin films were simultaneously deposited by RF magnetron sputtering at room temperature, on corning glass and SnO{sub 2}:F/glass substrates, in order to compare the photoacoustic response. The elemental and structural analysis of the V{sub 2}O{sub 5} films was performed by Rutherford backscattering spectroscopy and X-ray diffraction. The optical transmission and band gap were determined using UV-Vis spectroscopy. The electrical properties were measured using four-point probe measurements with the Van der Pauw geometry.

  11. Extreme ultraviolet emission from dense plasmas generated with sub-10-fs laser pulses

    CERN Document Server

    Osterholz, J; Cerchez, M; Fischer, T; Hemmers, D; Hidding, B; Pipahl, A; Pretzler, G; Rose, S J; Willi, O

    2008-01-01

    The extreme ultraviolet (XUV) emission from dense plasmas generated with sub-10-fs laser pulses with varying peak intensities up to 3*10^16 W/cm^2 is investigated for different target materials. K shell spectra are obtained from low Z targets (carbon and boron nitride). In the spectra a series limit for the hydrogen and helium like resonance lines is observed indicating that the plasma is at high density and pressure ionization has removed the higher levels. In addition, L shell spectra from titanium targets were obtained. Basic features of the K and L shell spectra are reproduced with computer simulations. The calculations include hydrodynamic simulation of the plasma expansion and collisional radiative calculations of the XUV emission.

  12. Multiple explosion pathways of the deuterated benzene trication in 9-fs intense laser fields.

    Science.gov (United States)

    Matsuda, Akitaka; Fushitani, Mizuho; Thomas, Richard D; Zhaunerchyk, Vitali; Hishikawa, Akiyoshi

    2009-03-19

    The fragmentation of deuterated benzene (C6D6) in ultrashort intense laser fields (9 fs, 1 x 10(15) W/cm2) is studied by the ion-coincidence momentum imaging technique. Five two-body and eight three-body Coulomb explosion pathways from the trication (C6D6(3+)), associated with the deprotonation and ring-opening reactions, are identified. It is found from the fragment momentum correlation that all the observed three-body explosion processes proceed sequentially via the two-body Coulomb explosion forming molecular dications, C(m)D(n)(2+), with (m,n) = (6,5), (5,5), (5,4), (4,4), (4,3), and (3,3), which further dissociate into pairs of monocations. The branching ratio of the fragmentation pathways estimated from the number of the observed coincidence events indicates that the fragmentation is nonstatistical.

  13. Bidirectional operation of 100 fs bound solitons in an ultra-compact mode-locked fiber laser.

    Science.gov (United States)

    Li, Lei; Ruan, Qiujun; Yang, Runhua; Zhao, Luming; Luo, Zhengqian

    2016-09-05

    We report on the experimental observation of bidirectional 100-fs bound solitons from a nanotube-mode-locked dispersion-managed Er-fiber laser with an ultra-simple linear cavity. Two mode-locked pulse trains in opposite directions are delivered simultaneously from the linear cavity. Under the pump power of <74 mW, both the bidirectional outputs of the laser work at the single-soliton state with pulse duration of 173 fs and 182 fs, respectively. Once the pump power is more than 74 mW, both the bidirectional outputs evolve into the two-soliton bound states with soliton separation of 1.53 ps. Interestingly, the bidirectional operations can show the different bound states, i.e. the forward bound solitons with phase difference of + π/2, and the backward ones with phase difference of -π/2. This is, to the best of our knowledge, the first demonstration of such compact bidirectional soliton fiber laser with the sub-200 fs pulses.

  14. FS laser processing of bio-polymer thin films for studying cell-to-substrate specific response

    Energy Technology Data Exchange (ETDEWEB)

    Daskalova, A., E-mail: a_daskalova@code.bg [Institute of Electronics, Bulgarian Academy of Sciences, 72, Tsarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria); Nathala, Chandra S.R. [Institute of General Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10/134, A-1040 Wien (Austria); Spectra-Physics Vienna, Fernkorngasse 10, 1100 Wien (Austria); Kavatzikidou, P.; Ranella, A. [Institute for Electronic Structure and Lasers-FORTH, P.O. Box 1385, Vassilika Vouton, 711 10 Heraklion, Crete (Greece); Szoszkiewicz, R. [Faculty of Materials Science and Engineering, Warsaw University of Technology, 141 Woloska Str., 02-507 Warsaw, Poland (Poland); Husinsky, W. [Institute of General Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10/134, A-1040 Wien (Austria); Fotakis, C. [Institute for Electronic Structure and Lasers-FORTH, P.O. Box 1385, Vassilika Vouton, 711 10 Heraklion, Crete (Greece)

    2016-09-30

    Highlights: • Systematic research in the field of fs laser interaction with biopolymers for application in tissue engineering. • Utilizing a new biopolymer blend of collagen/elastin material for studying the interaction process in the fs domain. • Obtaining of improved, circularly shaped, interconnected nanopores, with high reproducibility from collagen/elastin layer. • Observation of randomly arranged pattern outside modification zone due to formation of an impact wave over biofilm surface. • NIH/3T3 cell-interface interaction reveal a preferable cell migration on fs laser-modified surface array. - Abstract: The use of ultra-short pulses for nanoengineering of biomaterials opens up possibilities for biological, medical and tissue engineering applications. Structuring the surface of a biomaterial into arrays with micro- and nanoscale features and architectures, defines new roadmaps to innovative engineering of materials. Thin films of novel collagen/elastin composite and gelatin were irradiated by Ti:sapphire fs laser in air at central wavelength 800 nm, with pulse durations in the range of 30 fs. The size and shape as well as morphological forms occurring in the resulted areas of interaction were analyzed as a function of irradiation fluence and number of pulses by atomic force microscopy (AFM). The fs interaction regime allows generation of well defined micro porous surface arrays. In this study we examined a novel composite consisting of collagen and elastin in order to create a biodegradable matrix to serve as a biomimetic surface for cell attachment. Confocal microscopy images of modified zones reveal formation of surface fringe patterns with orientation direction alongside the area of interaction. Outside the crater rim a wave-like topography pattern is observed. Structured, on a nanometer scale, surface array is employed for cell-culture experiments for testing cell’s responses to substrate morphology. Mice fibroblasts migration was monitored

  15. Pulse shape measurements using single shot-frequency resolved optical gating for high energy (80 J) short pulse (600 fs) laser.

    Science.gov (United States)

    Palaniyappan, S; Shah, R C; Johnson, R; Shimada, T; Gautier, D C; Letzring, S; Jung, D; Hörlein, R; Offermann, D T; Fernández, J C; Hegelich, B M

    2010-10-01

    Relevant to laser based electron/ion accelerations, a single shot second harmonic generation frequency resolved optical gating (FROG) system has been developed to characterize laser pulses (80 J, ∼600 fs) incident on and transmitted through nanofoil targets, employing relay imaging, spatial filter, and partially coated glass substrates to reduce spatial nonuniformity and B-integral. The device can be completely aligned without using a pulsed laser source. Variations of incident pulse shape were measured from durations of 613 fs (nearly symmetric shape) to 571 fs (asymmetric shape with pre- or postpulse). The FROG measurements are consistent with independent spectral and autocorrelation measurements.

  16. Small-angle Thomson scattering of ultrafast laser pulses for bright, sub-100-fs x-ray radiation

    Directory of Open Access Journals (Sweden)

    Yuelin Li

    2002-04-01

    Full Text Available We propose a scheme for bright sub-100-fs x-ray radiation generation using small-angle Thomson scattering. Coupling high-brightness electron bunches with high-power ultrafast laser pulses, radiation with photon energies between 8 and 40 keV can be generated with pulse duration comparable to that of the incoming laser pulse and with peak spectral brightness close to that of the third-generation synchrotron light sources of ∼10^{20} photons s^{-1} mm^{-2} mrad^{-2} per 10^{-3} bandwidth. A preliminary dynamic calculation is performed to understand the property of this novel scattering scheme with relativistic laser intensities.

  17. High harmonics generation at the interaction of an intense fs laser pulse with an overdense plasma layer

    Science.gov (United States)

    Mihailescu, A.; Stancalie, V.; Pais, V.

    2014-04-01

    Harmonics generated with fs laser pulses are not only among the most intense sources in the wavelength range of a few tens of nanometers but also a far better source than X-ray lasers from the coherence point of view. It is anticipated, that in the near future, the harmonics issued from femtosecond laser-produced plasmas will represent a coherent source much brighter than all other XUV sources apart from the XFEL. These particular aspects, correlated with the fact that high order harmonics produced by reflection of an ultrashort and intense laser pulse on an overdense plasma layer impose virtually no restrictions on the intensity of the laser employed, lead the way to a series of potential applications in plasma diagnostics and nonlinear optics. This work presents a theoretical study on the high harmonics generation mechanism occurring at the reflection of a femtosecond Ti-Sapphire terawatt laser pulse (λ0 = 0.8 μm and pulse durations around 100-150 fs) on an overdense steep Al plasma layer. Insights on how different laser parameters influence this generation mechanism and its efficiency are provided.

  18. Frequency-doubled DBR-tapered diode laser for direct pumping of Ti:sapphire lasers generating sub-20 fs pulses.

    Science.gov (United States)

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika; Le, Tuan; Stingl, Andreas; Hasler, Karl-Heinz; Sumpf, Bernd; Erbert, Götz; Andersen, Peter E; Petersen, Paul Michael

    2011-06-20

    For the first time a single-pass frequency doubled DBR-tapered diode laser suitable for pumping Ti:sapphire lasers generating ultrashort pulses is demonstrated. The maximum output powers achieved when pumping the Ti:sapphire laser are 110 mW (CW) and 82 mW (mode-locked) respectively at 1.2 W of pump power. This corresponds to a reduction in optical conversion efficiencies to 75% of the values achieved with a commercial diode pumped solid-state laser. However, the superior electro-optical efficiency of the diode laser improves the overall efficiency of the Ti:sapphire laser by a factor > 2. The optical spectrum emitted by the Ti:sapphire laser when pumped with our diode laser shows a spectral width of 112 nm (FWHM). Based on autocorrelation measurements, pulse widths of less than 20 fs can therefore be expected.

  19. The influence of laser pulse duration and energy on ICP-MS signal intensity, elemental fractionation, and particle size distribution in NIR fs-LA-ICP-MS.

    Science.gov (United States)

    Diwakar, Prasoon K; Harilal, Sivanandan S; LaHaye, Nicole L; Hassanein, Ahmed; Kulkarni, Pramod

    Laser parameters, typically wavelength, pulse width, irradiance, repetition rate, and pulse energy, are critical parameters which influence the laser ablation process and thereby influence the LA-ICP-MS signal. In recent times, femtosecond laser ablation has gained popularity owing to the reduction in fractionation related issues and improved analytical performance which can provide matrix-independent sampling. The advantage offered by fs-LA is due to shorter pulse duration of the laser as compared to the phonon relaxation time and heat diffusion time. Hence the thermal effects are minimized in fs-LA. Recently, fs-LA-ICP-MS demonstrated improved analytical performance as compared to ns-LA-ICP-MS, but detailed mechanisms and processes are still not clearly understood. Improvement of fs-LA-ICP-MS over ns-LA-ICP-MS elucidates the importance of laser pulse duration and related effects on the ablation process. In this study, we have investigated the influence of laser pulse width (40 fs to 0.3 ns) and energy on LA-ICP-MS signal intensity and repeatability using a brass sample. Experiments were performed in single spot ablation mode as well as rastering ablation mode to monitor the Cu/Zn ratio. The recorded ICP-MS signal was correlated with total particle counts generated during laser ablation as well as particle size distribution. Our results show the importance of pulse width effects in the fs regime that becomes more pronounced when moving from femtosecond to picosecond and nanosecond regimes.

  20. 260 fs and 1 nJ pulse generation from a compact, mode-locked Tm-doped fiber laser.

    Science.gov (United States)

    Sobon, Grzegorz; Sotor, Jaroslaw; Pasternak, Iwona; Krajewska, Aleksandra; Strupinski, Wlodek; Abramski, Krzysztof M

    2015-11-30

    We report on generation of 260 fs-short pulses with energy of 1.1 nJ from a fully fiberized, monolithic Tm-doped fiber laser system. The design comprises a simple, graphene-based ultrafast oscillator and an integrated all-fiber chirped pulse amplifier (CPA). The system generates 110 mW of average power at 100.25 MHz repetition rate and central wavelength of 1968 nm. This is, to our knowledge, the highest pulse energy generated from a fully fiberized sub-300 fs Tm-doped laser, without the necessity of using grating-based dispersion compensation. Such compact, robust and cost-effective system might serve as a seed source for nonlinear frequency conversion or mid-infrared supercontinuum generation.

  1. Comparison of DLK incidence after laser in situ keratomileusis associated with two femtosecond lasers: Femto LDV and IntraLase FS60

    Directory of Open Access Journals (Sweden)

    Tomita M

    2013-07-01

    Full Text Available Minoru Tomita,1–3 Yuko Sotoyama,1 Satoshi Yukawa,1 Tadayuki Nakamura1 1Shinagawa LASIK Center, Chiyoda-ku, Tokyo, Japan; 2Department of Ophthalmology, Wenzhou Medical College, Wenzhou, People’s Republic of China; 3Eye Can Cataract Surgery Center, Manila, Philippines Purpose: To compare the incidence of diffuse lamellar keratitis (DLK after laser in situ keratomileusis (LASIK with flap creation using the Femto LDV and IntraLase™ FS60 femtosecond lasers. Methods: A total of 818 consecutive myopic eyes had LASIK performed using either Femto LDV or IntraLase FS60 for flap creation. The same excimer laser, the Allegretto Wave® Eye-Q Laser, was used for correcting refractive errors for all patients. In the preoperative examination, uncorrected distance visual acuity, corrected distance visual acuity, and manifest refraction spherical equivalent were measured. At the postop examination, the same examinations were performed along with a slit-lamp biomicroscopic examination, and patients with DLK were classified into stages. For the statistical analysis of the DLK occurrence rate and the visual and refractive outcomes, the Mann-Whitney’s U-test was used. Results: In the Femto LDV group with 514 eyes, 42 (8.17% had DLK. In the IntraLase FS60 group with 304 eyes, 114 (37.5% had DLK. There was a statistically significant difference in the DLK incidence rate between these groups (P < 0.0001. Both groups had excellent visual and refractive outcomes. Although low levels of DLK were observed for both groups, they did not affect visual acuity. Conclusion: While there were significantly fewer incidences of low level DLK when using Femto LDV, neither femtosecond laser induced high levels of DLK, and any postoperative DLK cleared up within 1 week. Therefore, both lasers provide excellent results, with no clinical differences, and both excel at flap creation for LASIK. Keywords: LASIK, Ziemer, Femto LDV, DLK, IntraLase FS60, femtosecond laser

  2. Observation of fs-laser spallative ablation using soft X-ray laser probe

    Science.gov (United States)

    Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro; Minami, Yasuo; Eyama, Takashi; Kakimoto, Naoya; Izutsu, Rui; Baba, Motoyoshi; Kawachi, Tetsuya; Suemoto, Tohru

    2017-03-01

    The initial stages of femtosecond laser ablation of gold were observed by single-shot soft X-ray laser interferometer and reflectometer. The ablation front surface and the spallation shell dome structure were observed from the results of the soft X-ray interferogram, reflective image, and shadowgraph. The formation and evolution of soft X-ray Newton's rings (NRs) were found by reflective imaging at the early stages of the ablation dynamics. The soft X-ray NRs are caused by the interference between the bulk ablated surface and nanometer-scale thin spallation layer. The spallation layer was kept at the late timing of the ablation dynamics, and the height of that reached over 100 μm. The temporal evolution of the bulk ablated surface was observed in the ablation dynamics. From these results, we have succeeded in obtaining the temporal evolution of the ablation front exfoliated from the gold surface.

  3. Interaction dynamics of fs-laser induced cavitation bubbles and their impact on the laser-tissue-interaction of modern ophthalmic laser systems

    Science.gov (United States)

    Tinne, N.; Ripken, T.; Lubatschowski, H.; Heisterkamp, A.

    2011-07-01

    A today well-known laser based treatment in ophthalmology is the LASIK procedure which nowadays includes cutting of the corneal tissue with ultra-short laser pulses. Instead of disposing a microkeratome for cutting a corneal flap, a focused ultra-short laser pulse is scanned below the surface of biological tissue causing the effect of an optical breakdown and hence obtaining a dissection. Inside the tissue, the energy of the laser pulses is absorbed by non-linear processes; as a result a cavitation bubble expands and ruptures the tissue. Hence, positioning of several optical breakdowns side by side generates an incision. Due to a reduction of the amount of laser energy, with a moderate duration of treatment at the same time, the current development of ultra-short pulse laser systems points to higher repetition rates in the range of even Megahertz instead of tens or hundreds of Kilohertz. In turn, this results in a pulse overlap and therefor a probable occurrence of interaction between different optical breakdowns and respectively cavitation bubbles of adjacent optical breakdowns. While the interaction of one single laser pulse with biological tissue is analyzed reasonably well experimentally and theoretically, the interaction of several spatial and temporal following pulses is scarcely determined yet. Thus, the aim of this study is to analyse the dynamic and interaction of two cavitation bubbles by using high speed photography. The applied laser pulse energy, the energy ratio and the spot distance between different cavitation bubbles were varied. Depending on a change of these parameters different kinds of interactions such as a flattening and deformation of bubble shape or jet formation are observed. The effects will be discussed regarding the medical ophthalmic application of fs-lasers. Based on these results a further research seems to be inevitable to comprehend and optimize the cutting effect of ultra-short pulse laser systems with high (> 500 kHz) repetition

  4. Optical properties of Nd{sup 3+} and Er{sup 3+} ions in fluoro-phosphate glasses: Effects of P{sub 2}O{sub 5} concentration and laser applications

    Energy Technology Data Exchange (ETDEWEB)

    Florez, A., E-mail: aflorez@uis.edu.c [Universidad Industrial de Santander, Escuela de Fisica, Laboratorio de Materiales Fotonicos, A. A. 678, Bucaramanga (Colombia); Ulloa, E.M.; Cabanzo, R. [Universidad Industrial de Santander, Escuela de Fisica, Laboratorio de Materiales Fotonicos, A. A. 678, Bucaramanga (Colombia)

    2009-12-04

    Materials based on fluoride glasses have been recognized as potential hosts for trivalent rare earth ions for different applications, such as fiber lasers. A broad range of stability, an appropriate refractive index and the optimization of the optical and mechanical properties are important characteristics that need to be improved in these new materials. In this work, we made a systematic study of the effect of substituting BaF{sub 2} for P{sub 2}O{sub 5} in the matrix: 35InF{sub 3}-20ZnF{sub 2}-(16 - x)BaF{sub 2}-xP{sub 2}O{sub 5}-20SrF{sub 2}-6GaF{sub 3}-2NaF-1.0REF{sub 3}, where RE = Nd{sup 3+}, Er{sup 3+}, with x = 4.0; 8.0; 12.0 and 16.0 molar concentration. In order to evaluate the material's thermal evolution, we obtained differential scanning calorimeter (DSC) measurements, noting the variations in the stability range. Measurements of the refractive index, absorption and luminescence at room temperature in the spectral range from 300 to 3200 nm were also obtained. An increase in refractive index with increasing P{sub 2}O{sub 5} concentrations was observed. The behavior of phonons in the samples was observed through of the absorption intensity and the narrowing of the bands in the visible part of the spectrum; the width of the bands in the infrared region did not change. From the areas of the absorption bands, we calculated the oscillator strengths for the all of the samples, and using the Judd-Ofelt intensity model, we calculated the characteristic spectroscopic parameters. Furthermore, we analyzed the intensity parameter in Nd{sup 3+} and Er{sup 3+} doped glasses to determine the material's suitability for laser applications.

  5. Scanning electron microscopy and ablation rates of hard dental tissue using 350-fs and 1-ns laser pulses

    Science.gov (United States)

    Neev, Joseph; Huynh, Daniel S.; Dan, Claudiu C.; White, Joel M.; Da Silva, Luiz B.; Feit, Michael D.; Matthews, Dennis L.; Perry, Michael D.; Rubenchik, Alexander M.; Stuart, Brent C.

    1996-04-01

    Lasers are currently limited in their ability to remove hard tissue. Furthermore, many laser systems, such as the long pulse infrared lasers used to ablate bone or hard dental tissue, also generate unacceptable heat levels and cause collateral tissue damage. Ultrashort pulse lasers, however, are highly efficient, quiet, and relatively free of charge. With recent developments now allowing operation at high pulse repetition rates, ultrashort pulse systems can yield significant material volume removal which can potentially match or even exceed conventional technology while still maintaining the minimal collateral damage characteristics. In this paper, the interaction characteristics of two pulse regimes with enamel and dentin: 350 fs pulse ablation of hard dental tissues is compared to the interaction with one nanosecond pulses. Ablation rates were characterized and surface morphology, and structure were evaluated using a scanning electron microscope.

  6. Confocal comparison of corneal reinnervation after small incision lenticule extraction (SMILE and femtosecond laser in situ keratomileusis (FS-LASIK.

    Directory of Open Access Journals (Sweden)

    Meiyan Li

    Full Text Available PURPOSE: To evaluate corneal reinnervation, and the corresponding corneal sensitivity and keratocyte density after small incision lenticule extraction (SMILE and femtosecond laser in situ keratomileusis (FS-LASIK. METHODS: In this prospective, non-randomized observational study, 18 patients (32 eyes received SMILE surgery, and 22 patients (42 eyes received FS-LASIK surgery to correct myopia. The corneal subbasal nerve density and microscopic morphological changes in corneal architecture were evaluated by confocal microscopy prior to surgery and at 1 week, 1 month, 3 months, and 6 months after surgery. A correlation analysis was performed between subbasal corneal nerve density and the corresponding keratocyte density and corneal sensitivity. RESULTS: The decrease in subbasal nerve density was less severe in SMILE-treated eyes than in FS-LASIK-treated eyes at 1 week (P = 0.0147, 1 month (P = 0.0243, and 3 months (P = 0.0498, but no difference was detected at the 6-month visit (P = 0.5277. The subbasal nerve density correlated positively with central corneal sensitivity in both groups (r = 0.416, P<0.0001, and r = 0.2567, P = 0.0038 for SMILE group and FS-LASIK group, respectively. The SMILE-treated eyes have a lower risk of developing peripheral empty space with epithelial cells filling in (P = 0.0005. CONCLUSIONS: The decrease in subbasal nerve fiber density was less severe in the SMILE group than the FS-LASIK group in the first 3 months following the surgeries. The subbasal nerve density was correlated with central corneal sensitivity.

  7. Generation of 70-fs pulses at 286 μm from a mid-infrared fiber laser

    Science.gov (United States)

    Woodward, R. I.; Hudson, D. D.; Fuerbach, A.; Jackson, S. D.

    2017-12-01

    We propose and demonstrate a simple route to few-optical-cycle pulse generation from a mid-infrared fiber laser through nonlinear compression of pulses from a holmium-doped fiber oscillator using a short length of chalcogenide fiber and a grating pair. Pulses from the oscillator with 265-fs duration at 2.86 {\\mu}m are spectrally broadened through self-phase modulation in step-index As2S3 fiber to 141-nm bandwidth and then re-compressed to 70 fs (7.3 optical cycles). These are the shortest pulses from a mid-infrared fiber system to date, and we note that our system is compact, robust, and uses only commercially available components. The scalability of this approach is also discussed, supported by numerical modeling.

  8. Laser impulse coupling measurements at 400 fs and 80 ps using the LULI facility at 1057 nm wavelength

    Science.gov (United States)

    Phipps, C. R.; Boustie, M.; Chevalier, J.-M.; Baton, S.; Brambrink, E.; Berthe, L.; Schneider, M.; Videau, L.; Boyer, S. A. E.; Scharring, S.

    2017-11-01

    At the École Polytechnique « LULI » facility, we have measured the impulse coupling coefficient Cm (target momentum per joule of incident laser light) with several target materials in vacuum, at 1057 nm and 400 fs and 80 ps pulse duration. A total of 64 laser shots were completed in a two-week experimental campaign, divided between the two pulse durations and among the materials. Our main purpose was to resolve wide discrepancies among reported values for Cm in the 100 ps region, where many applications exist. A secondary purpose was to compare Cm at 400 fs and 80 ps pulse duration. The 80 ps pulse was obtained by partial compression. Materials were Al, Ta, W, Au, and POM (polyoxymethylene, trade name Delrin). One application of these results is to pulsed laser ablation propulsion in space, including space debris re-entry, where narrow ranges in Cm and specific impulse Isp spell the difference between dramatic and uneconomical performance. We had difficulty measuring mass loss from single shots. Imparted momentum in single laser shots was determined using pendulum deflection and photonic Doppler velocimetry. Cm was smaller at the 400 fs pulse duration than at 80 ps. To our surprise, Cm for Al at 80 ps was at most 30 N/MW with 30 kJ/m2 incident fluence. On the other extreme, polyoxymethylene (POM, trade name Delrin) demonstrated 770 N/MW under these conditions. Together, these results offer the possibility of designing a Cm value suited to an application, by mixing the materials appropriately.

  9. Frequency-doubled DBR-tapered diode laser for direct pumping of Ti:sapphire lasers generating sub-20 fs pulses

    DEFF Research Database (Denmark)

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika

    2011-01-01

    For the first time a single-pass frequency doubled DBR-tapered diode laser suitable for pumping Ti:sapphire lasers generating ultrashort pulses is demonstrated. The maximum output powers achieved when pumping the Ti:sapphire laser are 110 mW (CW) and 82 mW (mode-locked) respectively at 1.2 W of p....... The optical spectrum emitted by the Ti:sapphire laser when pumped with our diode laser shows a spectral width of 112 nm (FWHM). Based on autocorrelation measurements, pulse widths of less than 20 fs can therefore be expected.......For the first time a single-pass frequency doubled DBR-tapered diode laser suitable for pumping Ti:sapphire lasers generating ultrashort pulses is demonstrated. The maximum output powers achieved when pumping the Ti:sapphire laser are 110 mW (CW) and 82 mW (mode-locked) respectively at 1.2 W...... of pump power. This corresponds to a reduction in optical conversion efficiencies to 75% of the values achieved with a commercial diode pumped solid-state laser. However, the superior electro-optical efficiency of the diode laser improves the overall efficiency of the Ti:sapphire laser by a factor > 2...

  10. 59 fs mode-locked Yb:KGW oscillator pumped by a single-mode laser diode

    Science.gov (United States)

    Kowalczyk, M.; Sotor, J.; Abramski, K. M.

    2016-03-01

    In this letter we present a passively mode-locked Yb:KGW oscillator pumped by a low power single-mode laser diode. Contrary to high power operation, single-mode pumping enabled us to suppress parasitic thermal effects, while keeping the setup compact and its alignment straightforward. Undisturbed mode-locking (ML) stability was achieved without active cooling of the gain medium and the laser was entirely self-starting. Pulses 59 fs in duration were obtained in a semiconductor saturable absorber mirror (SESAM)-assisted Kerr-lens mode-locked regime. The corresponding spectrum was 20.2 nm broad at a central wavelength of 1036 nm approaching the performance limit of the crystal. To the best of our knowledge, these are the shortest pulses generated from a Yb:KGW laser.

  11. 10-fs-level synchronization of photocathode laser with RF-oscillator for ultrafast electron and X-ray sources

    Science.gov (United States)

    Yang, Heewon; Han, Byungheon; Shin, Junho; Hou, Dong; Chung, Hayun; Baek, In Hyung; Jeong, Young Uk; Kim, Jungwon

    2017-01-01

    Ultrafast electron-based coherent radiation sources, such as free-electron lasers (FELs), ultrafast electron diffraction (UED) and Thomson-scattering sources, are becoming more important sources in today’s ultrafast science. Photocathode laser is an indispensable common subsystem in these sources that generates ultrafast electron pulses. To fully exploit the potentials of these sources, especially for pump-probe experiments, it is important to achieve high-precision synchronization between the photocathode laser and radio-frequency (RF) sources that manipulate electron pulses. So far, most of precision laser-RF synchronization has been achieved by using specially designed low-noise Er-fibre lasers at telecommunication wavelength. Here we show a modular method that achieves long-term (>1 day) stable 10-fs-level synchronization between a commercial 79.33-MHz Ti:sapphire laser oscillator and an S-band (2.856-GHz) RF oscillator. This is an important first step toward a photocathode laser-based femtosecond RF timing and synchronization system that is suitable for various small- to mid-scale ultrafast X-ray and electron sources.

  12. Structure and properties of silver doped SnSe{sub 2} and Ge{sub 2}Sb{sub 2}Te{sub 5} thin films prepared by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Popescu, M.; Sava, F.; Lorinczi, A.; Tomescu, A.; Simion, C.; Matei, E. [National Institute R and D of Materials Physics, Atomistilor str. 105 bis, P. O. Box MG. 7, 77125 Bucharest-Magurele-Ilfov (Romania); Velea, A. [National Institute R and D of Materials Physics, Atomistilor str. 105 bis, P. O. Box MG. 7, 77125 Bucharest-Magurele-Ilfov (Romania); Faculty of Physics, University of Bucharest, P.O. Box MG. 5, 77125 Bucharest-Magurele-Ilfov (Romania); Socol, G.; Mihailescu, I.N. [National Institute of Lasers, Plasma and Radiation Physics, P. O. Box MG. 6, 77125 Bucharest-Magurele-Ilfov (Romania); Andonie, A.; Stamatin, I. [Faculty of Physics, University of Bucharest, P.O. Box MG. 5, 77125 Bucharest-Magurele-Ilfov (Romania)

    2010-03-15

    Amorphous thin films of SnSe{sub 2} and Ge{sub 2}Sb{sub 2}Te{sub 5} doped by different amount of silver (0.1, 0.2, 0.5 and 1 Ag atoms per formula unit) have been prepared by pulsed laser deposition (PLD) starting from solid polycrystalline targets. The films were investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The good gas sensing properties for CO, as well as the sensitivity for CH{sub 4} and NO of the Ag doped SnSe{sub 2} films have been demonstrated in the composition SnSe{sub 2}Ag{sub 0.2}. The structural effect of silver introduced in Ge{sub 2}Sb{sub 2}Te{sub 5} matrix has been investigated. The freshly deposited thin films doped by various amount of Ag develop three phases: an amorphous one, and two crystalline phases consisting of a major fcc cubic phase of AgSbTe{sub 2} and a minor cubic phase of composition Ag{sub 2}Te. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  13. Near monochromatic 20 Me V proton acceleration using fs laser irradiating Au foils in target normal sheath acceleration regime

    Energy Technology Data Exchange (ETDEWEB)

    Torrisi, L., E-mail: Lorenzo.Torrisi@unime.it; Ceccio, G.; Cannavò, A. [Department of Physics Sciences-MIFT, Messina University, V.le F.S. d' Alcontres 31, 98166 S. Agata, Messina (Italy); Cutroneo, M. [Nuclear Physics Institute, ASCR, 250 68 Rez (Czech Republic); Batani, D.; Boutoux, G.; Jakubowska, K.; Ducret, J. E. [CELIA, Université de Bordeaux 1, UMR5107–CNRS - CEA, Talence (France)

    2016-04-15

    A 200 mJ laser pulse energy, 39 fs-pulse duration, 10 μm focal spot, p-polarized radiation has been employed to irradiate thin Au foils to produce proton acceleration in the forward direction. Gold foils were employed to produce high density relativistic electrons emission in the forward direction to generate a high electric field driving the ion acceleration. Measurements were performed by changing the focal position in respect of the target surface. Proton acceleration was monitored using fast SiC detectors in time-of-flight configuration. A high proton energy, up to about 20 Me V, with a narrow energy distribution, was obtained in particular conditions depending on the laser parameters, the irradiation conditions, and a target optimization.

  14. Near monochromatic 20 Me V proton acceleration using fs laser irradiating Au foils in target normal sheath acceleration regime

    Science.gov (United States)

    Torrisi, L.; Cutroneo, M.; Ceccio, G.; Cannavò, A.; Batani, D.; Boutoux, G.; Jakubowska, K.; Ducret, J. E.

    2016-04-01

    A 200 mJ laser pulse energy, 39 fs-pulse duration, 10 μm focal spot, p-polarized radiation has been employed to irradiate thin Au foils to produce proton acceleration in the forward direction. Gold foils were employed to produce high density relativistic electrons emission in the forward direction to generate a high electric field driving the ion acceleration. Measurements were performed by changing the focal position in respect of the target surface. Proton acceleration was monitored using fast SiC detectors in time-of-flight configuration. A high proton energy, up to about 20 Me V, with a narrow energy distribution, was obtained in particular conditions depending on the laser parameters, the irradiation conditions, and a target optimization.

  15. LS&T and CMS FY 2004 Feasibility Proposal 04-FS-006 - Ceramic Laser Materials Interim Report - June 8, 2004

    Energy Technology Data Exchange (ETDEWEB)

    Soules, T; Clapsaddle, B; Schaffers, K; Landingham, R

    2005-02-03

    The purpose of this memo is to give an update on our work on ceramic laser materials--feasibility proposal 04-FS-006. Transparent ceramic materials have several major advantages over single crystals in laser applications including, ease and robustness of manufacturing, large apertures, design flexibility, fracture toughness, high activator concentrations, uniformity of composition, no residual stress, and others discussed in the proposal. After a decade of working on making transparent YAG:Nd in 1995 Japanese workers demonstrated samples for the first time that performed as well in lasers as their single crystal counterparts. Since then several laser materials have been made and evaluated. For these reasons, developing ceramic laser materials is the most exciting and futuristic materials topic in today's major solid-state laser conferences. The highlights and executive summary of our work to date are: (1) Ordered a slab of transparent YAG:Nd from Konoshima Chemical Co. for evaluation in the SSHCL. Konoshima is the only company in the world currently making ceramic laser materials for sale. Our slab, the largest one made to date, will arrive within a week and will be evaluated in the SSHCL. (2) Met with the inventor of the Konoshima laser ceramic, Dr. Takagimi Yanagitani, and discussed synthesis and performance of these materials in an all day session at LLNL on May 17. (3) Made our first LLNL in-house nano-sized yttrium aluminum garnet by the CMS sol-gel process. (4) Successfully sintering several samples of nano-particle YAG to near translucency. In this report we will discuss each of the above items and include where relevant pictures or tables or references. In addition to reporting interim results this memo will serve as a reference and a place to put relevant data from subsequent samples throughout the study.

  16. [Scanning electron microscopic investigations of cutting edge quality in lamellar keratotomy using the Wavelight femtosecond laser (FS-200) : What influence do spot distance and an additional tunnel have?

    Science.gov (United States)

    Hammer, T; Höche, T; Heichel, J

    2018-01-01

    Femtosecond lasers (fs-lasers) are established cutting instruments for the creation of LASIK flaps. Previous studies often showed even rougher surfaces after application of fs-laser systems compared to lamellar keratotomy with mechanical microkeratomes. When cutting the cornea with fs-lasers, an intrastromal gas development occurs, which has a potentially negative influence on the cutting quality if the gas cannot be dissipated; therefore, manufacturers have chosen the way of gas assimilation in so-called pockets. The investigated system creates a tunnel which opens under the conjunctiva. The aim of this study was to investigate the effects of a tunnel as well as the influence of different spot distances on the quality of cut surfaces and edges. In this experimental study on freshly enucleated porcine eyes (n = 15), the following cuts were carried out with the FS-200 (Wavelight, Erlangen, Germany): 1. standard setting (spot and line separation 8 µm), 2. with tunnel for gas drainage, 3. without gas-conducting tunnel, 4. with increased spot spacing (spot and line separation 9 μm instead of 8 μm) and 5. with reduced spot spacing (spot and line separation 7 μm instead of 8 μm). Subsequently, scanning electron microscopy (FEI Quanta 650, Hillsboro, OR) of the cut edges and surfaces as well as the gas drain tunnel were performed. The evaluation was based on an established score. The current fs-laser system (200 Hz) is able to create smooth cutting surfaces and sharp edges. The changed density of laser pulses compared to the standard settings with a reduced or increased distance between the pulses, did not achieve any further improvement in the surface quality. The gas-conducting tunnel could be detected by scanning electron microscope. In the case of cutting without a tunnel, roughened surfaces and irregularities on the cutting edges were found. When the FS-200 fs-laser is used, LASIK cuts with very smooth cut surfaces and sharp cutting

  17. Laser-induced periodic surface structures on fused silica upon cross-polarized two-color double-fs-pulse irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Höhm, S., E-mail: hoehm@mbi-berlin.de.de [Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Straße 2A, D-12489 Berlin (Germany); Herzlieb, M.; Rosenfeld, A. [Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Straße 2A, D-12489 Berlin (Germany); Krüger, J. [BAM Bundesanstalt für Materialforschung und–prüfung, Unter den Eichen 87, D-12205 Berlin (Germany); Bonse, J., E-mail: joern.bonse@bam.de [BAM Bundesanstalt für Materialforschung und–prüfung, Unter den Eichen 87, D-12205 Berlin (Germany)

    2015-05-01

    Graphical abstract: - Highlights: • LIPSS formation on fused silica is studied upon cross-polarized two-color (400 and 800 nm) double-fs-pulse irradiation. • LIPSS orientation follows the polarization of the first pulse. • LIPSS periods are determined by the wavelength of the first pulse. • LIPSS area is increased for temporally overlapping pulses due to nonlinear absorption. - Abstract: The dynamics of the formation of laser-induced periodic surface structures (LIPSS) on fused silica upon irradiation with linearly polarized fs-laser pulses (50 fs pulse duration) is studied by cross-polarized two-color double-fs-pulse experiments. In order to analyze the relevance of temporally distributed energy deposition in the early stage of LIPSS formation, a Mach-Zehnder interferometer was used for generating multiple double-pulse sequences at two different wavelengths (400 and 800 nm). The inter-pulse delay between the individual cross-polarized pulses of each sequence was systematically varied in the sub-ps range and the resulting LIPSS morphologies were characterized by scanning electron microscopy. It is found that the polarization of the first laser pulse arriving to the surface determines the orientation and the periodicity of the LIPSS. These two-color experiments further confirm the importance of the ultrafast energy deposition to the silica surface for LIPSS formation, particularly by the first laser pulse of each sequence. The second laser pulse subsequently reinforces the previously seeded spatial LIPSS characteristics (period, orientation)

  18. Efficient chirped-pulse amplification of sub-20 fs laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Shinichi; Yamakawa, Koichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    We have developed a model for ultrabroadband and ultrashort pulse amplification including the effects of a pulse shaper for regenerative pulse shaping, gain narrowing and gain saturation in the amplifiers. Thin solid etalons are used to control both gain narrowing and gain saturation during amplification. This model has been used to design an optimized Ti:sapphire amplifier system for producing efficiently pulses of < 20-fs duration with approaching peak and average powers of 100 TW and 20 W. (author)

  19. Sub-100  fs Tm:MgWO4 laser at 2017  nm mode locked by a graphene saturable absorber.

    Science.gov (United States)

    Wang, Yicheng; Chen, Weidong; Mero, Mark; Zhang, Lizhen; Lin, Haifeng; Lin, Zhoubin; Zhang, Ge; Rotermund, Fabian; Cho, Young Jun; Loiko, Pavel; Mateos, Xavier; Griebner, Uwe; Petrov, Valentin

    2017-08-15

    We present the first sub-100 fs bulk solid-state laser in the 2-μm spectral range employing the monoclinic Tm3+-dopedMgWO4 crystal as an active medium. By applying a graphene-based saturable absorber and chirped mirrors for dispersion management, stable self-starting mode-locked operation at 2017 nm was achieved. Nearly Fourier-limited pulses as short as 86 fs featuring a bandwidth of 53 nm were generated at a repetition rate of 76 MHz. A pulse energy of 1.1 nJ was achieved at 87 MHz for a pulse duration of 96 fs. The mode-locked Tm3+:MgWO4 laser exhibits excellent stability with a fundamental beat note extinction ratio of 80 dBc above noise level.

  20. Fs-pulsed laser deposition of PbTe and PbTe/Ag thermoelectric thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bellucci, A. [CNR-ISM, Monterotondo Stazione, Rome (Italy); Universita di Roma Sapienza, Dipartimento di Fisica, Rome (Italy); Cappelli, E.; Trucchi, D.M. [CNR-ISM, Monterotondo Stazione, Rome (Italy); Orlando, S. [CNR-ISM, U.O.S. Tito Scalo Zona Industriale, Tito Scalo, PZ (Italy); Medici, L. [CNR-IMAA, Tito Scalo, PZ (Italy); Mezzi, A.; Kaciulis, S. [CNR -ISMN, Monterotondo Stazione, Rome (Italy); Polini, R. [Universita di Roma Tor Vergata, Dip. Scienze Tecnologie Chimiche, Rome (Italy)

    2014-10-15

    For the first time, thermoelectric thin films were fabricated by femtosecond pulsed laser deposition (fs-PLD) that represents a challenging technological solution for this application since it provides a correct film stoichiometry compared to the starting target, capability of native nanostructuring and a high deposition rate. In particular, this paper shows a preliminary work on PbTe and PbTe/Ag thin films deposited at different substrate temperatures by fs-PLD from a microcrystalline PbTe target. Structural, morphological and compositional characterizations of the deposited films were performed to demonstrate the formation of films composed by crystalline nanograins (about 35 nm size) and characterized by a correct stoichiometry. A remarkable deposition rate of 1.5 nm/s was evaluated. The electrical conductivity and the Seebeck coefficient (thermopower) were measured as a function of operating temperature to derive the thermoelectric power factor that was found to be less than a factor 2 with respect to the bulk materials. Finally, a discussion about the influence of compositional and structural properties of the deposited films on the related thermoelectric performances was presented. (orig.)

  1. A 158 fs 5.3 nJ fiber-laser system at 1 mu m using photonic bandgap fibers for dispersion control and pulse compression

    DEFF Research Database (Denmark)

    Nielsen, C.K.; Jespersen, Kim Giessmann; Keiding, S.R.

    2006-01-01

    We demonstrate a 158 fs 5.3 nJ mode-locked laser system based on a fiber oscillator, fiber amplifier and fiber compressor. Dispersion compensation in the fiber oscillator was obtained with a solid-core photonic bandgap (SC-PBG) fiber spliced to standard fibers, and external compression is obtained...

  2. Laser-induced damage of Ta{sub 2}O{sub 5}/SiO{sub 2} narrow-band interference filters under different 1064 nm Nd:YAG laser modes

    Energy Technology Data Exchange (ETDEWEB)

    Gao Weidong [R and D Center for Optical Thin Flim Coatings, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, No. 390, Qinghe Road, Jiading, P.O. Box 800-211, Shanghai 201800 (China)]. E-mail: wdgao@mail.siom.ac.cn; Zhan Meiqiong [R and D Center for Optical Thin Flim Coatings, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, No. 390, Qinghe Road, Jiading, P.O. Box 800-211, Shanghai 201800 (China); Fan Shuhai [R and D Center for Optical Thin Flim Coatings, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, No. 390, Qinghe Road, Jiading, P.O. Box 800-211, Shanghai 201800 (China); Shao Janda [R and D Center for Optical Thin Flim Coatings, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, No. 390, Qinghe Road, Jiading, P.O. Box 800-211, Shanghai 201800 (China); Fan Zhengxiu [R and D Center for Optical Thin Flim Coatings, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, No. 390, Qinghe Road, Jiading, P.O. Box 800-211, Shanghai 201800 (China)

    2005-08-31

    The laser-induced damage (LID) behavior of narrow-band interference filters was investigated with a Nd:YAG laser at 1064 nm under single-pulse mode and free-running mode. The absorption measurement of such coatings was performed with surface thermal lensing (STL) technique. The damage morphologies under the two different laser modes were also studied in detail. It was found that all the filters exhibited a pass-band-center-dependent absorption and laser-induced damage threshold (LIDT) behavior, but the damage morphologies were diverse. The explanation was given with the analysis of the electric field distribution and the operational behavior of the irradiation laser.

  3. Fabrication of Super Hydrophobic Surfaces by fs Laser Pulses : How to Produce Self-Cleaning Surfaces

    NARCIS (Netherlands)

    Groenendijk, M.N.W.

    2008-01-01

    The chair of Applied Laser Technology of the University of Twente, The Netherlands, is performing research into applications of ultrashort pulsed lasers for micromachining. In a recent project, PhD student Max Groenendijk developed a method for the production of super water repellant surfaces by

  4. InAs/GaSb Type-II superlattice photodiode array inter-pixel region blue-shift by femtosecond (fs) laser anneal

    Science.gov (United States)

    Das, Sona; Das, Utpal

    2017-09-01

    A post-growth blue-shift in the band gap of an undoped InAs/GaSb Type-II superlattice (5.5 μm cutoff wavelength), as a result of 775 nm, 150 fs laser annealing, is presented. A band gap blue-shift of ∼72 meV in the {{{p}}}+- and p-layer etched inter-pixel region, laser annealed superlattice is achieved. Using an inter-diffusion model, the dominant group-III and group-V diffusion coefficients are found to be 1.33× {10}-21 {{{m}}}2 {{{s}}}-1 and 4.8× {10}-22 {{{m}}}2 {{{s}}}-1 respectively. Confirmation of the unaltered condition of the superlattice in a Ti/Au masked pixel area establishes this blue-shifted superlattice band gap to be the reason behind the improved inter-pixel isolation resulting from the fs laser annealing technique.

  5. Surface modification of polymethylmethacrylate irradiated with 60 fs single laser pulses

    Czech Academy of Sciences Publication Activity Database

    Klinger, D.; Sobierajski, R.; Nietubyc, R.; Krzywinski, J.; Pelka, J.; Juha, Libor; Jurek, M.; Zymierska, D.; Guizard, S.; Merdji, H.

    2009-01-01

    Roč. 78, Suppl. 10 (2009), S71-S74 ISSN 0969-806X R&D Projects: GA AV ČR KAN300100702; GA MŠk LC510; GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR IAA400100701 Institutional research plan: CEZ:AV0Z10100523 Keywords : polymethylmethacrylate (PMMA) * IR laser ablation * femtosecond laser pulse Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.149, year: 2009

  6. Scattering effects of glass-embedded microstructures by roughness controlled fs-laser micromachining

    Science.gov (United States)

    Lo Turco, Sara; Di Donato, Andrea; Criante, Luigino

    2017-06-01

    We report a full roughness analysis carried out upon the internal walls of fs-fabricated micro-structures embedded in fused silica glass. In addition to the standard mapping methods based on RMS evaluation, we performed a spectral analysis to compare different types of surface morphology. In detail, introducing the correlation length L c as a key parameter to describe the profile periodicity, we highlight that the bottom- top- and side-wall of a square micro-channel show a different surface order and differently affect the light scattering. This is further validated by fast Fourier transform calculations and supported by beam transmission holograms. Here we suggest that proper beam shaping could ensure uniform energy distribution and low scattering effects.

  7. All-optical characterization of fs-laser induced refractive index changes in bulk and at the surface of zinc phosphate glasses

    Science.gov (United States)

    Hernandez-Rueda, J.; Semenov, V.; Troy, N.; Smith, C. E.; Brow, R. K.; Krol, D. M.

    2015-03-01

    The permanent refractive index change induced by ultrashort laser pulses in zinc phosphate glasses has been investigated both at the surface and in bulk. At the sample surface, irradiations have been performed by using loosely focused single fs-laser pulses at different energies. Optical microscopy images of the irradiations illustrate an interferometric pattern in form of concentric Newton rings due to the laser induced multilayer system (unmodified glass, thin laser-modified layer, air). This experimental reflectivity modulation along with simulations based on Abeles theory for multilayer optical systems allows retrieving laser-induced refractive index changes on the order of Δns= -10-3. In bulk, fs-laser written waveguides have been generated by translating the sample with respect to a tightly focused laser beam. The so-produced waveguides have been characterized by studying the optical near field of the TEM00 guided mode at 660 nm and using white light microscopy. The optical changes linked to the inscribed waveguides have been characterized by measuring the far field output profiles yielding values of approximately Δnb= +3·10-4. The laser-modified optical properties in bulk and at the surface will be linked to the glass structural changes as well as discussed in terms of the role of the incubation effects for multi-pulse processing.

  8. Angle-resolved coherent wave mixing using a 4  fs ultra-broad bandwidth laser.

    Science.gov (United States)

    Mercer, I P; Witting, T; Driver, T; Cogdell, R J; Marangos, J P; Tisch, J W G

    2017-02-15

    We demonstrate angle-resolved coherent (ARC) wave mixing using 4 fs light pulses derived from a laser source that spans 550-1000 nm. We believe this to be the shortest pulse duration used to date in coherent multi-dimensional spectroscopy. The marriage of this ultra-broad band, few-cycle coherent source with the ARC technique will permit new investigations of the interplay between energy transfers and quantum superposition states spanning 8200  cm-1. We applied this configuration to measurements on the photosynthetic low light (LL) complex from Rhodopseudomonas palustris in solution at ambient temperature. We observe bi-exponential population dynamics for energy transfer across 5500  cm-1 (0.65 eV), which we attribute to energy transfer from the Qx transition of bacteriochlorophylls to the B850 pigment of the complex. We believe for the first time, to the best of our knowledge, we demonstrate that ARC maps can be recorded using a single laser pulse.

  9. Controlling plasma distributions as driving forces for ion migration during fs laser writing

    CERN Document Server

    Fernandez, Toney Teddy; Hoyo, Jesus; Sotillo, Belen; Fernandez, Paloma; Solis, Javier

    2014-01-01

    The properties of structures written inside dielectrics with high repetition rate femtosecond lasers are known to depend strongly on the complex interplay of a large number of writing parameters. Recently, ion migration within the laser-excited volume has been identified as a powerful mechanism for changing the local element distribution and producing efficient optical waveguides. In this work it is shown that the transient plasma distribution induced during laser irradiation is a reliable monitor for predicting the final refractive index distribution of the waveguide caused by ion migration. By performing in-situ plasma emission microscopy during the writing process inside a La-phosphate glass it is found that the long axis of the plasma distribution determines the axis of ion migration, being responsible for the local refractive index increase. This observation is also valid when strong positive or negative spherical aberration is induced, greatly deforming the focal volume and inverting the index profile. ...

  10. TruMicro Series 2000 sub-400 fs class industrial fiber lasers: adjustment of laser parameters to process requirements

    Science.gov (United States)

    Kanal, Florian; Kahmann, Max; Tan, Chuong; Diekamp, Holger; Jansen, Florian; Scelle, Raphael; Budnicki, Aleksander; Sutter, Dirk

    2017-02-01

    The matchless properties of ultrashort laser pulses, such as the enabling of cold processing and non-linear absorption, pave the way to numerous novel applications. Ultrafast lasers arrived in the last decade at a level of reliability suitable for the industrial environment.1 Within the next years many industrial manufacturing processes in several markets will be replaced by laser-based processes due to their well-known benefits: These are non-contact wear-free processing, higher process accuracy or an increase of processing speed and often improved economic efficiency compared to conventional processes. Furthermore, new processes will arise with novel sources, addressing previously unsolved challenges. One technical requirement for these exciting new applications will be to optimize the large number of available parameters to the requirements of the application. In this work we present an ultrafast laser system distinguished by its capability to combine high flexibility and real time process-inherent adjustments of the parameters with industry-ready reliability. This industry-ready reliability is ensured by a long experience in designing and building ultrashort-pulse lasers in combination with rigorous optimization of the mechanical construction, optical components and the entire laser head for continuous performance. By introducing a new generation of mechanical design in the last few years, TRUMPF enabled its ultrashort-laser platforms to fulfill the very demanding requirements for passively coupling high-energy single-mode radiation into a hollow-core transport fiber. The laser architecture presented here is based on the all fiber MOPA (master oscillator power amplifier) CPA (chirped pulse amplification) technology. The pulses are generated in a high repetition rate mode-locked fiber oscillator also enabling flexible pulse bursts (groups of multiple pulses) with 20 ns intra-burst pulse separation. An external acousto-optic modulator (XAOM) enables linearization

  11. Third-order optical nonlinearities in bulk and fs-laser inscribed waveguides in strengthened alkali aluminosilcate glass

    Science.gov (United States)

    Almeida, Gustavo F. B.; Almeida, Juliana M. P.; Martins, Renato J.; De Boni, Leonardo; Arnold, Craig B.; Mendonca, Cleber R.

    2018-01-01

    The development of advanced photonics devices requires materials with large optical nonlinearities, fast response times and high optical transparency, while at the same time allowing for the micro/nano-processing needed for integrated photonics. In this context, glasses have been receiving considerable attention given their relevant optical properties which can be specifically tailored by compositional control. Corning Gorilla® Glass (strengthened alkali aluminosilicate glass) is well-known for its use as a protective screen in mobile devices, and has attracted interest as a potential candidate for optical devices. Therefore, it is crucial not only to expand the knowledge on the fabrication of waveguides in Gorilla Glass under different regimes, but also to determine its nonlinear optical response, both using fs-laser pulses. Thus, this paper reports, for the first time, characterization of the third-order optical nonlinearities of Gorilla Glass, as well as linear and nonlinear characterization of waveguide written with femtosecond pulses under the low repetition rate regime (1 kHz).

  12. Label-free SHG imaging and spectral FLIM of corneas using a sub-15 fs laser microscope

    Science.gov (United States)

    Batista, Ana; Breunig, Hans Georg; Uchugonova, Aisada; Seitz, Berthold; Morgado, António Miguel; König, Karsten

    2014-02-01

    Alterations to the corneal cell metabolism or to the structural organization of collagen fibrils occur in several corneal and systemic pathologies. In this work we resort to multiphoton microscopy corneal imaging to achieve a characterization of the corneal state. Using fluorescence lifetime imaging microscopy (FLIM) the assessment of the metabolic state of corneal cells is possible, whereas second harmonic generation (SHG) imaging can be used to assess corneal structural alterations. A sub-15 fs near-infrared laser source with a broad excitation spectrum was used for SHG imaging and FLIM. The broad spectrum allows simultaneous excitation of both metabolic co-factors. The signals were collected by a photomultiplier tubes (PMT) detector with 16 simultaneous recording channels, which allowed the separation of fluorophores autofluorescence based on their emission wavelengths. We were able to successfully image ex-vivo human and porcine cornea at multiple depths. Simultaneous NADH and flavin autofluorescence, SHG of collagen fibrils, and stroma autofluorescence imaging was performed which may in future allow an improved characterization of the metabolic and structural alterations of the corneal tissue due to pathophysiological conditions. This would be an important step towards a better understanding of corneal dystrophies and systemic metabolic disorders.

  13. All-fiber high-power monolithic femtosecond laser at 1.59 µm with 63-fs pulse width

    Science.gov (United States)

    Hekmat, M. J.; Omoomi, M.; Gholami, A.; Yazdabadi, A. Bagheri; Abdollahi, M.; Hamidnejad, E.; Ebrahimi, A.; Normohamadi, H.

    2018-01-01

    In this research, by adopting an alternative novel approach to ultra-short giant pulse generation which basically originated from difficulties with traditional employed methods, an optimized Er/Yb co-doped double-clad fiber amplifier is applied to boost output average power of single-mode output pulses to a high level of 2-W at 1.59-µm central wavelength. Output pulses of approximately 63-fs pulse width at 52-MHz repetition rate are obtained in an all-fiber monolithic laser configuration. The idea of employing parabolic pulse amplification for stretching output pulses together with high-power pulse amplification using Er/Yb co-doped active fibers for compressing and boosting output average power plays crucial role in obtaining desired results. The proposed configuration enjoys massive advantages over previously reported literature which make it well-suited for high-power precision applications such as medical surgery. Detailed dynamics of pulse stretching and compressing in active fibers with different GVD parameters are numerically and experimentally investigated.

  14. Regenerative amplification of femtosecond pulses: Design and construction of a sub-100fs, {mu}J laser system

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, A.B. [Universitaet Karlsruhe (Germany). Institut fuer Angewandte Physik]|[Lawrence Berkeley National Lab., CA (United States)

    1996-10-01

    Femtosecond lasers are a powerful tool for a wealth of applications in physics, chemistry and biology. In most cases, however, their use is fundamentally restricted to a rather narrow spectral range. This thesis deals with the construction and characterization of a femtosecond light source for spectroscopic applications which overcomes that restriction. It is demonstrated how the output of a continuously pumped Ti:sapphire femtosecond oscillator is amplified to the {mu}J level, while the pulse duration remains below 100fs. A combination of continuous pumping, acousto-optic switching and Ti:Al{sub 2}O{sub 3} as a gain medium allows amplification at high repetition rates. By focusing the high energy pulses into a sapphire crystal, a broad-band continuum can be generated, extended in wavelengths over several hundred nanometers. To accomplish amplification of three orders of magnitude while maintaining the pulse length, a regenerative multipass amplifier system was built. The thesis describes theoretical design, realization and characterization of the system. Theoretical calculations and preliminary measurements were carried out and allow a critical evaluation of the final performance.

  15. Regenerative Amplification of Femtosecond Pulses: Design andConstruction of a sub-100fs, muon J Laser System

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, Andreas B. [Univ. of California, Berkeley, CA (United States)

    1996-10-01

    Femtosecond lasers are a powerful tool for a wealth of applications in physics, chemistry and biology. In most cases, however, their use is fundamentally restricted to a rather narrow spectral range. This thesis deals with the construction and characterization of a femtosecond light source for spectroscopic applications which overcomes that restriction. It is demonstrated how the output of a continuously pumped Ti:sapphire femtosecond oscillator is amplified to the μJ level,while the pulse duration remains below 100 fs. A combination of continuous pumping, acousto-optic switching and Ti:Al2O3 as a gain medium allows amplification at high repetition rates. By focusing the high energy pulses into a sapphire crystal, a broad-band continuum can be generated, extended in wavelengths over several hundred nanometers. To accomplish amplification of three orders of magnitude while maintaining the pulse length, a regenerative multipass amplifier system was built. The thesis describes theoretical design, realization and characterization of the system. Theoretical calculations and preliminary measurements were carried out and allow a critical evaluation of the final performance.

  16. Few-cycle, broadband, mid-infrared optical parametric oscillator pumped by a 20-fs Ti:sapphire laser

    Science.gov (United States)

    Chaitanya Kumar, Suddapalli; Esteban-Martin, Adolfo; Ideguchi, Takuro; Yan, Ming; Holzner, Simon; Hänsch, Theodor W; Picqué, Nathalie; Ebrahim-Zadeh, Majid

    2014-01-01

    A few-cycle, broadband, singly-resonant optical parametric oscillator (OPO) for the mid-infrared based on MgO-doped periodically-poled LiNbO3 (MgO:PPLN), synchronously pumped by a 20-fs Ti:sapphire laser is reported. By using crystal interaction lengths as short as 250 µm, and careful dispersion management of input pump pulses and the OPO resonator, near-transform-limited, few-cycle idler pulses tunable across the mid-infrared have been generated, with as few as 3.7 optical cycles at 2682 nm. The OPO can be continuously tuned over 2179-3732 nm (4589-2680 cm-1) by cavity delay tuning, providing up to 33 mW of output power at 3723 nm. The idler spectra exhibit stable broadband profiles with bandwidths spanning over 422 nm (FWHM) recorded at 3732 nm. The effect of crystal length on spectral bandwidth and pulse duration is investigated at a fixed wavelength, confirming near-transform-limited idler pulses for all grating interaction lengths. By locking the repetition frequency of the pump laser to a radio-frequency reference, and without active stabilization of the OPO cavity length, an idler power stability better than 1.6% rms over >2.75 hours is obtained when operating at maximum output power, in excellent spatial beam quality with TEM00 mode profile. Photograph shows a multigrating MgO:PPLN crystal used as a nonlinear gain medium in the few-cycle femtosecond mid-IR OPO. The visible light is the result of non-phase-matched sum-frequency mixing between the interacting beams. PMID:25793016

  17. 760  fs diode-pumped mode-locked laser with Yb:LuAG crystal at 1032  nm.

    Science.gov (United States)

    Su, Xian-Cui; Wang, Yi-Ran; He, Jing-Liang; Zhao, Ru-Wei; Zhang, Pei-Xiong; Hang, Yin; Hou, Jia; Zhang, Bai-Tao; Zhao, Shuang

    2015-08-10

    In this study, we experimentally demonstrate the generation of 760 fs pulse duration from a diode-pumped Yb:LuAG mode-locked laser at 1032 nm. At the repetition rate of 58.6 MHz, the maximum average power of 1.07 W was obtained, corresponding to the peak power of 24 kW. To our knowledge, these results represent the shortest pulse duration and highest peak power ever obtained for a 1032 nm mode-locked laser with Yb:LuAG crystal.

  18. Matching sub-fs electron bunches for laser-driven plasma acceleration at SINBAD

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, J., E-mail: jun.zhu@desy.de [Deutsches Elektronen-Synchrotron, DESY, Hamburg (Germany); Universität Hamburg, Hamburg (Germany); Assmann, R.W.; Dorda, U.; Marchetti, B. [Deutsches Elektronen-Synchrotron, DESY, Hamburg (Germany)

    2016-09-01

    We present theoretical and numerical studies of matching sub-femtosecond space-charge-dominated electron bunch into the Laser-plasma Wake Field Accelerator (LWFA) foreseen at the SINBAD facility. The longitudinal space-charge (SC) effect induced growths of the energy spread and longitudinal phase-space chirp are major issues in the matching section, which will result in bunch elongation, emittance growth and spot size dilution. In addition, the transverse SC effect would lead to a mismatch of the beam optics if it were not compensated for. Start-to-end simulations and preliminary optimizations were carried out in order to understand the achievable beam parameters at the entrance of the plasma accelerator.

  19. Uncorrected and Corrected Distance Visual Acuity, Predictability, Efficacy, and Safety after Femtosecond Laser in Situ Keratomileusis (FS-LASIK) and Refractive Lenticule extraction (ReLEx) for Moderate and High Myopia

    DEFF Research Database (Denmark)

    Vestergaard, Anders; Justesen, Birgitte Larsen; Melsen, Charlotte

    Title: Uncorrected and Corrected Distance Visual Acuity, Predictability, Efficacy, and Safety after Femtosecond Laser in Situ Keratomileusis (FS-LASIK) and Refractive Lenticule extraction (ReLEx) for Moderate and High Myopia. Vestergaard A., Justesen B., Melsen C., Lyhne N., Department of Ophthal......Title: Uncorrected and Corrected Distance Visual Acuity, Predictability, Efficacy, and Safety after Femtosecond Laser in Situ Keratomileusis (FS-LASIK) and Refractive Lenticule extraction (ReLEx) for Moderate and High Myopia. Vestergaard A., Justesen B., Melsen C., Lyhne N., Department...... months after surgery. Conclusions: Both FS-LASIK and ReLEx are efficient in treating myopia and myopic astigmatism. ReLEx is a promising new all-in-one femtosecond laser refractive procedure with results, concerning predictability and efficacy, that seemed comparable to or better than FS-LASIK after 3...

  20. Fabrication and evaluation of In sub 0 sub . sub 5 sub 2 Al sub 0 sub . sub 4 sub 8 As/In sub 0 sub . sub 5 sub 3 Ga sub 0 sub . sub 4 sub 7 As/InP quantum cascade lasers

    CERN Document Server

    Farmer, C D

    2000-01-01

    far-field measurements on the mesa-etched QC lasers confirmed the lasing of higher order modes and more importantly, dramatic changes in the far-field distributions with current. Measurement of the threshold current density gave the waveguide losses approx 30 cm sup - sup 1 which was subsequently traced to an excessive doping level in the substrate. Novel design and fabrication of QC lasers was demonstrated with the planar selective wet oxidation (PSWOX) QC laser. Despite the high waveguide losses arising from the substrate, the PSWOX QCLs still performed very well. Optically they were far superior to our mesa-etched QC lasers, possessing an output beam with a very low divergence and whose far-field profile was stable with increasing drive current. The lasers' ability to dissipate heat also appeared to be enhanced over its counterparts, as demonstrated by its high characteristic temperature T sub 0 (approx 142 K). However, this particular structure was let down by the very poor electrical confinement which le...

  1. Laser assisted removal of synthetic painting-conservation materials using UV radiation of ns and fs pulse duration: Morphological studies on model samples

    Energy Technology Data Exchange (ETDEWEB)

    Pouli, P., E-mail: ppouli@iesl.forth.gr [Institute of Electronic Structure and Laser, Foundation for Research and Technology Hellas (IESL-FORTH), P.O. Box 1385, Heraklion, 71110 Crete (Greece); Nevin, A. [Institute of Electronic Structure and Laser, Foundation for Research and Technology Hellas (IESL-FORTH), P.O. Box 1385, Heraklion, 71110 Crete (Greece); Courtauld Institute of Art, University of London, Somerset House, Strand, WC2R 0RN, London (United Kingdom); Andreotti, A.; Colombini, P. [Dipartimento di Chimica e Chimica Industriale, Universita di Pisa, via Risorgimento 35, 56126 Pisa (Italy); Georgiou, S. [Institute of Electronic Structure and Laser, Foundation for Research and Technology Hellas (IESL-FORTH), P.O. Box 1385, Heraklion, 71110 Crete (Greece); Fotakis, C. [Institute of Electronic Structure and Laser, Foundation for Research and Technology Hellas (IESL-FORTH), P.O. Box 1385, Heraklion, 71110 Crete (Greece); Department of Physics, University of Crete, P.O. Box 2208, Heraklion, 71003 (Greece)

    2009-02-15

    In an effort to establish the optimal parameters for the cleaning of complex layers of polymers (mainly based on acrylics, vinyls, epoxys known as Elvacite, Laropal, Paraloid B72, among others) applied during past conservation treatments on the surface of wall paintings, laser cleaning tests were performed with particular emphasis on the plausible morphological modifications induced in the remaining polymeric material. Pulse duration effects were studied using laser systems of different pulse durations (ns and fs) at 248 nm. Prior to tests on real fragments from the Monumental Cemetery in Pisa (Italy) which were coated with different polymers, attention was focused on the study of model samples consisting of analogous polymer films cast on quartz disks. Ultraviolet irradiation is strongly absorbed by the studied materials both in ns and fs irradiation regimes. However, it is demonstrated that ultrashort laser pulses result in reduced morphological alterations in comparison to ns irradiation. In addition, the dependence of the observed alterations on the chemical composition of the consolidation materials in both regimes was examined. Most importantly, it was shown that in this specific conservation problem, an optimum cleaning process may rely not only on the minimization of laser-induced morphological changes but also on the exploitation of the conditions that favour the disruption of the adhesion between the synthetic material and the painting.

  2. Generation of 70-fs pulses at 2.86  μm from a mid-infrared fiber laser.

    Science.gov (United States)

    Woodward, R I; Hudson, D D; Fuerbach, A; Jackson, S D

    2017-12-01

    We propose and demonstrate a simple route to few-optical-cycle pulse generation from a mid-infrared fiber laser through nonlinear compression of pulses from a holmium-doped fiber oscillator using a short length of chalcogenide fiber and a grating pair. Pulses from the oscillator with 265-fs duration at 2.86 μm are spectrally broadened through self-phase modulation in step-index As 2 S 3 fiber to 141-nm bandwidth and then re-compressed to 70 fs (7.3 optical cycles). These are the shortest pulses from a mid-infrared fiber system to date, and we note that our system is compact, robust, and uses only commercially available components. The scalability of this approach is also discussed, supported by numerical modeling.

  3. Detection of carbon monoxide (CO) in sooting hydrocarbon flames using femtosecond two-photon laser-induced fluorescence (fs-TPLIF)

    Science.gov (United States)

    Wang, Yejun; Kulatilaka, Waruna D.

    2018-01-01

    Ultrashort-pulse, femtosecond (fs)-duration, two-photon laser-induced fluorescence (fs-TPLIF) measurements of carbon monoxide (CO) are reported in rich, sooting hydrocarbon flames. CO-TPLIF detection using conventional nanosecond or picosecond lasers are often plagued by photochemical interferences, specifically under fuel-rich flames conditions. In the current study, we investigate the commonly used CO two-photon excitation scheme of the B1Σ+ ← X1Σ+ electronic transition, using approximately 100-fs-duration excitation pulses. Fluorescence emission was observed in the Ångström band originating from directly populated B1Σ+ upper state, as well as, in the third positive band from collisionally populated b3Σ+ upper state. The current work was focused on the Ångström band emission. Interference from nascent C2 emissions originating from hot soot particles in the flame could be reduced to a negligible level using a narrower detection gate width. In contrast, avoiding interferences from laser-generated C2 Swan-band emissions required specific narrowband spectral filtering in sooting flame conditions. The observed less than quadratic laser pulse energy dependence of the TPLIF signal suggests the presence of strong three-photon ionization and stimulated emission processes. In a range of CH4/air and C2H4/air premixed flames investigated, the measured CO fluorescence signals agree well with the calculated equilibrium CO number densities. Reduced-interference CO-TPLIF imaging in premixed C2H4/O2/N2 jet flames is also reported.

  4. Single particle deformation and analysis of the same silica coated gold nanorods before and after fs-laser pulse excitation

    NARCIS (Netherlands)

    Albrecht, W.|info:eu-repo/dai/nl/369492242; Deng, Tian-Song; Goris, Bart; van Huis, M.A.|info:eu-repo/dai/nl/304097586; Bals, Sarah; van Blaaderen, Alfons|info:eu-repo/dai/nl/092946488

    2016-01-01

    We performed single particle deformation experiments on silicacoated gold nanorods under femtosecond (fs) illumination. Changes in the particle shape were analyzed by electron microscopy and associated changes in the plasmon resonance by electron energy loss spectroscopy. Silica-coated rods were

  5. Ultra-compact (palm-top size) low-cost maintenance-free (>3000 h) diode-pumped femtosecond (160 fs) solid state laser source for multiphoton microscopy

    Science.gov (United States)

    Yamazoe, S.; Katou, M.; Kasamatsu, T.

    2009-02-01

    We propose and demonstrate a novel practical femtosecond laser source, which is to our knowledge, the smallest size and potentially low cost. The innovation is the simple linear cavity design utilizing soliton mode-locking induced by precise group velocity dispersion control. Average output power of 680 mW and pulse width of 162 fs were obtained at around 1045 nm from a diode-pumped Yb3+:KY(WO4)2 laser. The pulse repetition rate was 2.8 GHz, leading to a pulse peak power of 1.5 kW, which is sufficient for biomedical imaging. The laser module including the laser diode pump system has a footprint of 8×4 cm2. Under automatic current control condition, stable operation of 3000-hour was observed with an average power fluctuation of less than +/-10 %. Furthermore, under automatic power control condition, stable operation of 2000-hour was observed with an average power fluctuation of less than +/-1 %. Using this laser module, we successfully obtained clear two-photon fluorescence images of muntjac skin fibroblast cells stained with a combination of fluorescent stains (Alexa Fluor 488 phalloidin and Alexa Flour 555 goat anti-mouse lgG).

  6. 175 fs-long pulses from a high-power single-mode Er-doped fiber laser at 1550 nm

    Science.gov (United States)

    Elahi, Parviz; Kalaycıoğlu, Hamit; Li, Huihui; Akçaalan, Önder; Ilday, F. Ömer

    2017-11-01

    Development of Er-doped ultrafast lasers have lagged behind the corresponding developments in Yb- and Tm-doped lasers, in particular, fiber lasers. Various applications benefit from operation at a central wavelength of 1.5 μm and its second harmonic, including emerging applications such as 3D processing of silicon and 3D printing based on two-photon polymerization. We report a simple, robust fiber master oscillator power amplifier operating at 1.55 μm, implementing chirp pulse amplification using single-mode fibers for diffraction-limited beam quality. The laser generates 80 nJ pulses at a repetition rate of 43 MHz, corresponding to an average power of 3.5 W, which can be compressed down to 175 fs. The generation of short pulses was achieved using a design which is guided by numerical simulations of pulse propagation and amplification and manages to overturn gain narrowing with self-phase modulation, without invoking excessive Raman scattering processes. The seed source for the two-stage amplifier is a dispersion-managed passively mode-locked oscillator, which generates a ∼40 nm-wide spectrum and 1.7-ps linearly chirped pulses.

  7. Small Incision Lenticule Extraction (SMILE versus Femtosecond Laser-Assisted In Situ Keratomileusis (FS-LASIK for Myopia: A Systematic Review and Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Zeren Shen

    Full Text Available The goal of this study was to compare small incision lenticule extraction (SMILE with femtosecond laser-assisted in situ keratomileusis (FS-LASIK for treating myopia.The CENTRAL, EMBASE, PubMed databases and a Chinese database (SinoMed were searched in May of 2016. Twelve studies with 1,076 eyes, which included three randomized controlled trials (RCTs and nine cohorts, met our inclusion criteria. The overall quality of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE working group framework. Data were extracted and analysed at three to six months postoperatively. Primary outcome measures included a loss of one or more lines of best spectacle corrected visual acuity (BSCVA, uncorrected visual acuity (UCVA of 20/20 or better, mean logMAR UCVA, postoperative mean spherical equivalent (SE and postoperative refraction within ±1.0 D of the target refraction. Secondary outcome measures included ocular surface disease index (OSDI, tear breakup time (TBUT and Schirmer's 1 test (S1T as dry eye parameters, along with corneal sensitivity.The overall quality of evidence was considered to be low to very low. Pooled results revealed no significant differences between the two groups with regard to a loss of one or more lines in the BSCVA (OR 1.71; 95% CI: 0.81, 3.63; P = 0.16, UCVA of 20/20 or better (OR 0.71; 95% CI: 0.44, 1.15; P = 0.16, logMAR UCVA (MD 0.00; 95% CI: -0.03, 0.04; P = 0.87, postoperative refractive SE (MD -0.00; 95% CI: -0.05, 0.05; P = 0.97 or postoperative refraction within ±1.0 D of the target refraction (OR 0.78; 95% CI: 0.22, 2.77; P = 0.70 within six months postoperatively. The pooled analysis also indicated that the FS-LASIK group suffered more severely from dry eye symptoms (OSDI; MD -6.68; 95% CI: -11.76, -2.00; P = 0.006 and lower corneal sensitivity (MD 12.40; 95% CI: 10.23, 14.56; P < 0.00001 at six months postoperatively.In conclusion, both FS-LASIK and SMILE are safe

  8. Evaluation of the cone-shaped pickup performance for low charge sub-10 fs arrival-time measurements at free electron laser facilities

    Directory of Open Access Journals (Sweden)

    Aleksandar Angelovski

    2015-01-01

    Full Text Available An evaluation of the cone-shaped pickup performance as a part of the high bandwidth bunch arrival-time monitors (BAMs for a low charge sub-10 fs arrival-time measurements is presented. Three sets of pickups are installed at the free electron laser FLASH at Deutsches Elektronen-Synchrotron, the quasi-cw SRF accelerator ELBE at the Helmholtz-Zentrum Dresden-Rossendorf and the SwissFEL injector test facility at Paul Scherrer Institute. Measurements and simulations are in good agreement and the pickups fulfill the design specifications. Utilizing the high bandwidth BAM with the cone-shaped pickups, an improvement of the signal slope by a factor of 10 is demonstrated at ELBE compared to the BAM with a low bandwidth.

  9. Protons and electrons generated from a 5-{mu}m thick copper tape target irradiated by s-, circularly-, and p-polarized 55-fs laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z. [Advanced Photon Research Center, Japan Atomic Energy Agency, Umeimidai 8-1, Kizu, Kyoto 619-0215 (Japan); National Institute of Radiological Sciences, Anagawa 4-9-1, Inage, Chiba 263-8555 (Japan)], E-mail: lizhong@sinap.ac.cn; Daido, H. [Advanced Photon Research Center, Japan Atomic Energy Agency, Umeimidai 8-1, Kizu, Kyoto 619-0215 (Japan); Fukumi, A. [Advanced Photon Research Center, Japan Atomic Energy Agency, Umeimidai 8-1, Kizu, Kyoto 619-0215 (Japan); National Institute of Radiological Sciences, Anagawa 4-9-1, Inage, Chiba 263-8555 (Japan); Bulanov, S.V.; Sagisaka, A.; Ogura, K.; Yogo, A.; Nishiuchi, M.; Orimo, S.; Mori, M. [Advanced Photon Research Center, Japan Atomic Energy Agency, Umeimidai 8-1, Kizu, Kyoto 619-0215 (Japan); Oishi, Y.; Nayuki, T.; Fujii, T.; Nemoto, K. [Central Research Institute of Electric Power Industry, Nagasaka 2-6-1, Yokosuka, Kanagawa 240-0196 (Japan); Nakamura, S.; Noda, A. [Institute of Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Choi, I.W.; Sung, J.H.; Ko, D.-K.; Lee, J. [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)

    2007-10-01

    The angular distribution and energy spectra of energetic protons emitted from a 5-{mu}m thick copper tape target irradiated by p-, circularly-, and s-polarized 55-fs laser pulses with intensity of 8-9x10{sup 18} W/cm{sup 2} are measured. The protons are found in the rear target normal direction while the hot electrons are found in the laser propagation direction. The maximum energy of protons is equal to 1.34 MeV for p-polarized irradiation. The energy spectrum of protons depends strongly on the total amount of electrons but it does not so strongly depend on the electron angular distribution under our experiment conditions. Two-dimensional particle in cell simulations also show the maximal proton acceleration for the p-polarized pulse, less efficient acceleration for the circular polarization, and lower acceleration efficiency in the case of the s-polarization, which is related to the electron acceleration efficiency at the front side of the target.

  10. Analysis of the structure, configuration, and sizing of Cu and Cu oxide nanoparticles generated by fs laser ablation of solid target in liquids

    Energy Technology Data Exchange (ETDEWEB)

    Santillan, J. M. J. [Centro de Investigaciones Opticas (CIOp), (CONICET La Plata - CIC) (Argentina); Videla, F. A.; Schinca, D. C.; Scaffardi, L. B. [Centro de Investigaciones Opticas (CIOp), (CONICET La Plata - CIC) (Argentina); Departamento de Ciencias Basicas, Facultad de Ingenieria, UNLP (Argentina); Fernandez van Raap, M. B. [Departamento de Fisica-IFLP, Universidad Nacional de La Plata-CONICET, L. B. Scaffardi: CIOp CC3 (1897) Gonnet, La Plata (Argentina)

    2013-04-07

    We report on the analysis of structure, configuration, and sizing of Cu and Cu oxide nanoparticles (Nps) produced by femtosecond (fs) laser ablation of solid copper target in liquids. Laser pulse energy ranged between 500 {mu}J and 50 {mu}J. Water and acetone were used to produce the colloidal suspensions. The study was performed through optical extinction spectroscopy using Mie theory to fit the full experimental spectra, considering free and bound electrons size dependent contributions to the metal dielectric function. Raman spectroscopy and AFM technique were also used to characterize the sample. Considering the possible oxidation of copper during the fabrication process, two species (Cu and Cu{sub 2}O) arranged in two structures (bare core or core-shell) and in two configuration types (Cu-Cu{sub 2}O or Cu{sub 2}O-Cu) were considered for the fitting depending on the laser pulse energy and the surrounding media. For water at high energy, it can be observed that a Cu-Cu{sub 2}O configuration fits the experimental spectra of the colloidal suspension, while for decreasing energy and below a certain threshold, a Cu{sub 2}O-Cu configuration needs to be included for the optimum fit. Both species coexist for energies below 170 {mu}J for water. On the other hand, for acetone at high energy, optimum fit of the full spectrum suggests the presence a bimodal Cu-Cu{sub 2}O core-shell Nps distribution while for decreasing energy and below a 70 {mu}J threshold energy value, Cu{sub 2}O-Cu core-shell Nps must be included, together with the former configuration, for the fit of the full spectrum. We discuss possible reasons for the changes in the structural configuration of the core-shell Nps.

  11. Fs-laser microstructuring of laser-printed LiMn2O4 electrodes for manufacturing of 3D microbatteries

    Science.gov (United States)

    Pröll, J.; Kim, H.; Mangang, M.; Seifert, H. J.; Piqué, A.; Pfleging, W.

    2014-03-01

    Lithium manganese oxide composite cathodes are realized by laser-printing. The printed cathode is a composite and consists of active powder, binder and conductive agents. Laser-printed cathodes are first calendered and then laser structured using femtosecond-laser radiation in order to form three-dimensional (3D) micro-grids in the cathode material. Three-dimensional micro-grids in calendered/laser structured cathodes exhibit improved discharge capacity retention at a 1 C discharging rate. Calendered but unstructured cathodes indicate the poorest cycling behavior at 1 C discharge. The improved capacity retention and the reduced degradation of calendered/structured cathodes can be attributed to both the increased electrical contact through calendering as well as shortened Li-ion pathways due to laser-induced 3D microgrids.

  12. Real-time observation of round-trip resolved spectral dynamics in a stabilized fs fiber laser.

    Science.gov (United States)

    Li, Bowen; Yu, Ying; Wei, Xiaoming; Xu, Yiqing; Tsia, Kevin K; Wong, Kenneth K Y

    2017-04-17

    Fiber-stretcher based phase-lock loop (PLL) is a mature technique in fiber mode-locked lasers for repetition-rate stabilization. However, undesired side effects may be induced if not properly handled, which is easily overlooked owing to the lack of single-shot spectral analyzers. Thanks to the ultrafast spectral analyzing capability of optical time-stretch, an intriguing spectral dynamics is observed in a repetition-rate-stabilized nonlinear polarization rotation (NPR) mode-locked laser. Under the dynamic state, the optical spectra of pulses undergo dramatic evolution in every round trip while the pulse energy is relatively constant. Indicated by estimated cross-spectral densities, such spectral dynamics results in noticeable degradation in optical spectral coherence. The physical origin of the round-trip evolved spectral dynamics is attributed to the local birefringence induced by the fiber stretcher. Therefore, the results are helpful for a proper use of fiber-stretcher based PLL in fiber lasers, particularly when a good spectral coherence is desired. Furthermore, our study has also provided a potentially useful optical source for applications where fast spectral modulation is desired.

  13. Generation of spin waves by a train of fs-laser pulses: a novel approach for tuning magnon wavelength.

    Science.gov (United States)

    Savochkin, I V; Jäckl, M; Belotelov, V I; Akimov, I A; Kozhaev, M A; Sylgacheva, D A; Chernov, A I; Shaposhnikov, A N; Prokopov, A R; Berzhansky, V N; Yakovlev, D R; Zvezdin, A K; Bayer, M

    2017-07-18

    Currently spin waves are considered for computation and data processing as an alternative to charge currents. Generation of spin waves by ultrashort laser pulses provides several important advances with respect to conventional approaches using microwaves. In particular, focused laser spot works as a point source for spin waves and allows for directional control of spin waves and switching between their different types. For further progress in this direction it is important to manipulate with the spectrum of the optically generated spin waves. Here we tackle this problem by launching spin waves by a sequence of femtosecond laser pulses with pulse interval much shorter than the relaxation time of the magnetization oscillations. This leads to the cumulative phenomenon and allows us to generate magnons in a specific narrow range of wavenumbers. The wavelength of spin waves can be tuned from 15 μm to hundreds of microns by sweeping the external magnetic field by only 10 Oe or by slight variation of the pulse repetition rate. Our findings expand the capabilities of the optical spin pump-probe technique and provide a new method for the spin wave generation and control.

  14. Multiple ionization of Ne and Ar by intense 25 fs laser pulses: few-electron dynamics studied with ion momentum spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zrost, K [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Rudenko, A [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Ergler, Th [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Feuerstein, B [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Jesus, V L B de [Centro Federal de Educacao Tecnologica de Quimica de Nilopolis/RJ, Rua Lucio Tavares 1045, Centro-Nilopolis 26530-060, Rio de Janeiro (Brazil); Schroeter, C D [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Moshammer, R [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Ullrich, J [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

    2006-07-14

    Momentum distributions of Ne{sup 2-5+} and Ar{sup 2-7+} ions created by 795 nm, 25 fs laser pulses at intensities of up to 20 PW cm{sup -2} have been measured using a 'reaction microscope'. The experimental results indicate that below 2.0 PW cm{sup -2} the production of Ne{sup 3-4+} ions is dominated by n-fold electron impact ionization (e, ne) collisions of the recolliding electron with its parent ion. Multiple ionization of Ar is found to be dominated by mechanisms involving a combination of recollision-induced and field-induced steps as well as intermediate excitations in the whole range of intensities where non-sequential ionization occurs. Whereas a clear double peak structure characteristic for electron recollision was observed in the momentum distributions of up to Ne{sup 5+}, no signatures of non-sequential ionization were found in the spectra of Ar ions with the charge state higher than 4.

  15. An exhaustive study of laser damage in ion beam sputtered pure and mixture oxide thin films at 1030 nm with 500 fs pulse durations

    Science.gov (United States)

    Gallais, Laurent; Mangote, Benoit; Commandré, Mireille; Mende, Mathias; Jensen, Lars; Ehlers, Henrik; Jupé, Marco; Ristau, Detlev; Melninkaitis, Andrius; Sirutkaitis, Valdas; Kičas, Simonas; Tolenis, Tomas; Drazdys, Ramutis

    2012-11-01

    We report on the laser damage resistance of thin films prepared by Ion Beam Sputtering. The samples are fused silica substrates coated with single layer films of pure oxides (SiO2, Nb2O5, ZrO2, HfO2, Ta2O5, Al2O3, Sc2O3) and oxide mixtures with various ratios (Nb2O5/SiO2, ZrO2/SiO2, HfO2/SiO2, Ta2O5/SiO2, Al2O3/SiO2 and Sc2O3/SiO2). For this study the LIDT of more than 60 different samples have measured at 1030nm with pulse durations of 500fs with single pulse irradiation. The results are expressed and compared in terms of LIDT as a function of the measured band gap energy and refractive index. For simple oxide materials a linear evolution of the LIDT with bandgap is observed, with the exception of Sc2O3 material where a very high damage threshold is observed, compared to other high index materials. In the case of mixtures, a more complex behavior is evidenced.

  16. Femtosecond laser spectroscopy

    CERN Document Server

    Hannaford, Peter

    2005-01-01

    As concepts and methodologies have evolved over the past two decades, the realm of ultrafast science has become vast and exciting and has impacted many areas of chemistry, biology and physics, and other fields such as materials science, electrical engineering, and optical communication. The field has recently exploded with the announcement of a series of remarkable new developments and advances. This volume surveys this recent growth in eleven chapters written by leading international researchers in the field. It includes sections on femtosecond optical frequency combs, soft x-ray femtosecond laser sources, and attosecond laser sources. In addition, the contributors address real-time spectroscopy of molecular vibrations with sub-5-fs pulses and multidimensional femtosecond coherent spectroscopies for studying molecular and electron dynamics. Novel methods for measuring and characterizing ultrashort laser pulses and ultrashort pulses of light are also described. The topics covered are revolutionizing the field...

  17. 140-fs duration and 60-W peak power blue-violet optical pulses generated by a dispersion-compensated GaInN mode-locked semiconductor laser diode using a nonlinear pulse compressor.

    Science.gov (United States)

    Kono, Shunsuke; Watanabe, Hideki; Koda, Rintaro; Fuutagawa, Noriyuki; Narui, Hironobu

    2015-12-14

    Blue-violet optical pulses of 140-fs duration and 60-W peak power were obtained from a dispersion-compensated GaInN mode-locked semiconductor laser diode using a nonlinear pulse compression technique. Wavelength-dependent group velocity dispersion expressed by third-order phase dispersion was applied to the optical pulses using a pulse compressor with a spatial light modulator. The obtained optical pulses had the shortest duration ever obtained for a mode-locked semiconductor laser diode using edge-emitting type devices.

  18. Spectroscopy and tunable mid-infrared lasing of a novel gain medium: Cr sup 2 sup + doped Cd sub 0 sub . sub 8 sub 5 Mn sub 0 sub . sub 1 sub 5 Te

    CERN Document Server

    Seo, J T; Trivedi, S B; Kutcher, S W; Chen, R J; Wang, C C; Zong, H; Boyd, P R; Tardiff, W

    1999-01-01

    A novel mid-infrared transition-metal laser has been developed based on chromium (II)-doped Cd sub 0 sub . sub 8 sub 5 Mn sub 0 sub . sub 1 sub 5 Te. The characteristic spectroscopy features of Cr sup 2 sup + : Cd sub 0 sub . sub 8 sub 5 Mn sub 0 sub . sub 1 sub 5 Te are large absorption and emission cross sections (approx 10 sup - sup 1 sup 8 cm sup 2), a predicted absence of excited state absorption (ESA), and a broad emission band extending from 2.1 approx 3.5 mu m. The broad emission band makes Cr sup 2 sup + : Cd sub 0 sub . sub 8 sub 5 Mn sub 0 sub . sub 1 sub 5 Te very attractive for the development of a widely tunable mid-infrared laser. In initial studies, a laser tunability from 2.3 to 2.75 mu m has been demonstrated with a full width at half maximum of 2.3 nm. A larger tuning range seems possible with the appropriate optics. The highest slope efficiency achieved for a pulsed (2 Hz) free-running laser was 44.2%.

  19. A KK-monopole giant graviton in AdS{sub 5} x Y{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, Bert [Departamento de Fisica Teorica y del Cosmos and Centro Andaluz de Fisica de Particulas Elementales, Universidad de Granada, 18071 Granada (Spain); Lozano, Yolanda [Departamento de Fisica, Universidad de Oviedo, Avda. Calvo Sotelo 18, 33007 Oviedo (Spain); Rodriguez-Gomez, Diego [Department of Physics, Princeton University, Princeton, NJ 08540 (United States)

    2007-06-15

    We construct a new giant graviton solution in AdS{sub 5} x Y{sub 5}, with Y{sub 5} a quasi-regular Sasaki-Einstein manifold, consisting on a Kaluza-Klein monopole wrapped around the Y{sub 5} and with its Taub-NUT direction in AdS{sub 5}. We find that this configuration has minimal energy when put in the centre of AdS{sub 5}, where it behaves as a massless particle. When we take Y{sub 5} to be S{sup 5}, we provide a microscopical description in terms of multiple gravitational waves expanding into the fuzzy S{sup 5} defined as an S{sup 1} bundle over the fuzzy CP{sup 2}. Finally we provide a possible field theory dual interpretation of the construction.

  20. Antiferromagnetic CsCrF{sub 5} and canted antiferromagnetism in RbCrF{sub 5} and KCrF{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Jagličić, Zvonko, E-mail: zvonko.jaglicic@imfm.si [University of Ljubljana, Faculty of Civil and Geodetic Engineering, and Institute of Mathematics, Physics and Mechanics, Jadranska 19, 1000 Ljubljana (Slovenia); Mazej, Zoran, E-mail: zoran.mazej@ijs.si [Department of Inorganic Chemistry and Technology, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia)

    2017-07-15

    Highlights: • Cr(IV) ions are antiferromagnetically coupled within chains in ACrF{sub 5} (A = Cs, Rb, K). • Small structural difference causes huge difference in magnetic properties below 10 K. • Canted antiferromagnetism has been observed in RbCrF{sub 5} and KCrF{sub 5} at low temperature. - Abstract: In ACrF{sub 5} (A = Cs, Rb, K), Cr(IV) ions are coordinated by six fluoride ligands where the resulting CrF{sub 6} octahedra share cis vertexes to form infinite chains of ([Cr{sup IV}F{sub 5}]{sup −}){sub n}. The geometry of the latter in Cs compound differs from that in K and Rb compounds. The results of investigations of the magnetic behaviour of these compounds have shown that an antiferromagnetic superexchange interaction is present within the chains with J{sub Cs} = −10.2 cm{sup −1}, J{sub Rb} = −13.3 cm{sup −1}, and J{sub K} = −13.1 cm{sup −1}. Additional ferromagnetic-like long-range ordering has been observed in KCrF{sub 5} and RbCrF{sub 5} below 6 K which can be explained, in a correlation with their crystal structures, as canted antiferromagnetism.

  1. SeaWiFS

    Data.gov (United States)

    Washington University St Louis — SEAWiFS_US is a high resolution (1km) satellite dataset derived from the eight wavelength SEAWiFS sensor. The dataset also includes the aerosol reflectance over the...

  2. Anomalous strain relief and physical properties of La sub 0 sub . sub 5 Ca sub 0 sub . sub 5 MnO sub 3 films

    CERN Document Server

    Choi, C; Kim, D H; Lim, K D; Noh, T W; Jung, C U; Oh, S J; Lee, K B

    2000-01-01

    La sub 0 sub . sub 5 Ca sub 0 sub . sub 5 MnO sub 3 films were grown using pulsed laser deposition. Several factors, such as variation of substrates, interface effects, and annealing effects, influencing the properties of the grown films were investigated. As-grown films on LaAlO sub 3 substrates showed anomalous strain relief; they had strained and partly relaxed layers, both of which had tetragonal structures. On SrTiO sub 3 substrates, only coherently strained layers were observed. Such a difference of growth behaviors cannot be explained solely in terms of lattice mismatch since only partly relaxed layers appeared on LaAlO sub 3 and relaxed layers were obtained after annealing. The transport and the magnetic properties of the annealed films were quite different from those of the as-grown films.

  3. Design and construction of a periodic magnetic structure of SmCo{sub 5} magnets

    Energy Technology Data Exchange (ETDEWEB)

    Migliano, A.C.C.; Stopa, C.R.S. [Centro Tecnico Aerospacial, Sao Paulo (Brazil); Cardoso, J.R. [Escola Politecnica-USP, Sao Paulo (Brazil); Zgainski, F.X.; Coulomb, J.L. [ENSIEG, Saint Martin d`Heres (France). Lab. d`Electrotechnique de Grenoble

    1997-03-01

    A SmCo{sub 5} permanent magnet periodic structure was developed to generate a sinusoidal space-varying magnetic field. This device was designed to be utilized in the wiggler of a infra-red Free-Electron Laser (IR-FEL). To design the structure, finite-element computer codes that calculate magnetic fields in two and three dimensions were utilized. The results obtained from the computer simulations and the mechanical design of the built structure are presented.

  4. A new approach to theoretical investigations of high harmonics generation by means of fs laser interaction with overdense plasma layers. Combining particle-in-cell simulations with machine learning.

    Science.gov (United States)

    Mihailescu, A.

    2016-12-01

    Within the past decade, various experimental and theoretical investigations have been performed in the field of high-order harmonics generation (HHG) by means of femtosecond (fs) laser pulses interacting with laser produced plasmas. Numerous potential future applications thus arise. Beyond achieving higher conversion efficiency for higher harmonic orders and hence harmonic power and brilliance, there are more ambitious scientific goals such as attaining shorter harmonic wavelengths or reducing harmonic pulse durations towards the attosecond and even the zeptosecond range. High order harmonics are also an attractive diagnostic tool for the laser-plasma interaction process itself. Particle-in-Cell (PIC) simulations are known to be one of the most important numerical instruments employed in plasma physics and in laser-plasma interaction investigations. The novelty brought by this paper consists in combining the PIC method with several machine learning approaches. For predictive modelling purposes, a universal functional approximator is used, namely a multi-layer perceptron (MLP), in conjunction with a self-organizing map (SOM). The training sets have been retrieved from the PIC simulations and also from the available literature in the field. The results demonstrate the potential utility of machine learning in predicting optimal interaction scenarios for gaining higher order harmonics or harmonics with particular features such as a particular wavelength range, a particular harmonic pulse duration or a certain intensity. Furthermore, the author will show how machine learning can be used for estimations of electronic temperatures, proving that it can be a reliable tool for obtaining better insights into the fs laser interaction physics.

  5. Magnetoelastic behaviour of Gd sub 5 Ge sub 4

    CERN Document Server

    Magen, C; Algarabel, P A; Marquina, C; Ibarra, M R

    2003-01-01

    A complete investigation of the complex magnetic behaviour of Gd sub 5 Ge sub 4 by means of linear thermal expansion and magnetostriction measurements (5-300 K, 0-120 kOe) has been carried out. Our results support the suggested existence in this system of a coupled crystallographic-magnetic transition from a Gd sub 5 Ge sub 4 -type Pnma (antiferromagnetic) to a Gd sub 5 Si sub 4 -type Pnma (ferromagnetic) state. Strong magnetoelastic effects are observed at the field-induced first-order magnetic-martensitic transformation. A revised magnetic and crystallographic H- T phase diagram is proposed.

  6. Electronic structure and magnetism of YCo sub 5 , YNi sub 5 and YCo sub 3 Ni sub 2

    CERN Document Server

    Kitagawa, I; Yamada, H; Aoki, M

    1997-01-01

    Dependences of the magnetic moment on the lattice constant for binary and pseudo-binary compounds YCo sub 5 , YNi sub 5 and Y(Co sub 0 sub . sub 6 Ni sub 0 sub . sub 4) sub 5 with a hexagonal CaCu sub 5 -type structure are studied by an ab initio calculation on a self-consistent linear muffin-tin orbital method within the atomic sphere approximation. It is found that Co moments in YCo sub 5 decrease abruptly at a critical lattice constant smaller than the observed one. On the other hand, Ni moments in YNi sub 5 are shown to appear at a lattice constant a little larger than the observed one. Similar calculations are carried out for the ordered compound YCo sub 3 Ni sub 2 , where Co and Ni atoms occupy the 3g and 2c sites, respectively. It is shown that Co and Ni atoms in this compound lose their moments at a lattice constant slightly smaller than the observed one. It is also found that the Co atom on the 3g site in YCo sub 5 and YCo sub 3 Ni sub 2 has two magnetic states, a high-moment state and a low-moment o...

  7. The Gd anisotropy in GdCo sub 5

    Energy Technology Data Exchange (ETDEWEB)

    Radwanski, R.J.; Franse, J.J.M.; Quang, P.H.; Kayzel, F.E. (Van der Waals-Zeeman Lab., Univ. van Amsterdam (Netherlands))

    1992-02-01

    High-field magnetization curves of single-crystalline GdCo{sub 5} have been measured at 4.2 K up to 35 T in order to clarify the presence of an extra Gd contribution to the magnetocrystalline anisotropy. The 3d-4f exchange interactions and the Co sublattice anisotropy have been evaluated in GdCo{sub 5} and Gd{sub 2}Fe{sub 17}. No significant Gd contribution to the anisotropy has been revealed. (orig.).

  8. Evaluation of Biomechanical Changes in Myopia Patients with Unsatisfactory Corneas After Femto Second-Laser In Situ Keratomileusis (FS-LASIK) Concurrent with Accelerated Corneal Collagen Cross-Linking Using Corvis-ST: Two-Year Follow-Up Results.

    Science.gov (United States)

    Xu, Weiwei; Tao, Ye; Wang, Liqiang; Huang, Yifei

    2017-07-27

    BACKGROUND Some myopia patients with unsatisfactory corneas consider corneal refractive surgery for different reasons. Accelerated corneal collagen crosslinking (ACXL) is an effective method to enhance the resistance of the cornea. The present investigation was designed to evaluate the changes of biomechanical properties in patients with myopia and thin corneas after femtosecond-laser in situ keratomileusis (FS-LASIK) concurrent with ACXL. MATERIAL AND METHODS A prospective study was designed. A total of 22 eyes of 11 myopia astigmatism patients with unsatisfactory corneas were enrolled. The patients were assigned to femtosecond-laser in situ keratomileusis concurrent with accelerated corneal collagen crosslinking (FS-LASIK-ACXL). The follow-up duration was 24 months. Manifest refraction, uncorrected (UDVA), and corrected distance visual acuity (CDVA), ultra-high-speed camera (Corvis-ST), corneal topography, anterior segment OCT (AS-OCT), Pentacam, and endothelial cell density (ECD) were examined before and after the operation. The corneal biomechanical and refractive data was analyzed using SAS9.3. Data were analyzed through normal distribution test and variance of analysis. The difference was considered as statistically significant when pcorneas, and it does not increase the risk of iatrogenic keratectasia.

  9. Hydrides of CeNi/sub 5/, MmNi/sub 5/, Ca/sub 0/ /sub 2/(Ce/sub 0/ /sub 65/Mm/sub 0/ /sub 35/)/sub 0/ /sub 8/Ni/sub 5/, Ca/sub 0/ /sub 2/Ce/sub 0/ /sub 8/Ni/sub 5/, Ca/sub 0/ /sub 2/Mm/sub 0/ /sub 8/Ni/sub 5/, and mixed CeNi/sub 5//MmNi/sub 5/

    Energy Technology Data Exchange (ETDEWEB)

    Lakner, J.F.; Chow, T.S.

    1982-09-01

    Six intermetallic alloys (CeNi/sub 5/, MmNi/sub 5/, Ca/sub 0/ /sub 2/(Ce/sub 0/ /sub 65/Mm/sub 0/ /sub 35/)/sub 0/ /sub 8/Ni/sub 5/, Ca/sub 0/ /sub 2/Ce/sub 0/ /sub 8/Ni/sub 5/, Ca/sub 0/ /sub 2/Mm/sub 0/ /sub 8/Ni/sub 5/, and a mixed alloy, CeNi/sub 5//MmNi/sub 5/) were investigated with respect to their suitability to provide high hydrogen capacity and their potential for use in providing substantial hydrogen pressure at both low and high temperatures. A second phase of our investigation dealt with ball-milling and hydriding and dehydriding cycles to produce fine particles for use in hydride powder transfer studies. A summary of several Van't Hoff plots is also included for hydride-forming alloys.

  10. Intraband relaxation time in wurtzite InGaN quantum-well lasers and comparison with experiment

    CERN Document Server

    Park, S H

    1999-01-01

    The intraband relaxation time for wurtzite (WZ) 3.5-nm In sub 0 sub . sub 1 sub 5 Ga sub 0 sub . sub 8 sub 5 N/In sub 0 sub . sub 0 sub 2 Ga sub 0 sub . sub 9 sub 8 N quantum well (QW) lasers is investigated theoretically. The results are also compared with those obtained from fitting the experimental data with a non-Markovian gain model with many-body effects. An intraband relaxation time of 25 fs is obtained from the comparison with experiment, which is in reasonably good agreement with the calculated value of 20 fs at the subband edge. These values are significantly shorter than those (40 - 100 sf) reported for zinc-blende crystals, such as InP and GaAs. This is because the hole effective masses of GaN are larger than those of GaAs and InP.

  11. Electronic band structure of PuCoGa sub 5

    CERN Document Server

    Szajek, A

    2003-01-01

    The electronic band structure is presented for PuCoGa sub 5 , the recently discovered superconductor with T sub C approx 18 K. The band structure is calculated by the tight-binding linear muffin-tin orbital method in the atomic sphere approximation. (letter to the editor)

  12. Heat capacity of GdNi sub 5

    Energy Technology Data Exchange (ETDEWEB)

    Szewczyk, A. (Inst. of Physics, Polish Academy of Sciences, Warsaw (Poland)); Radwanski, R.J.; Franse, J.J.M.; Nakotte, H. (Natuurkundig Lab., Univ. van Amsterdam (Netherlands))

    1992-02-01

    The heat capacity of GdNi{sub 5} was measured from 1.3 to 48 K in a fixed magnetic field (up to 5 T). The electronic, phonon, and magnetic contributions were separated. Temperature dependences of magnetic specific heat and entropy were calculated in the molecular field approximation. They are in good agreement with the experimental results. (orig.).

  13. Structure and physical properties of Cr{sub 5}B{sub 3}-type Ta{sub 5}Si{sub 3} and Ta{sub 5}Ge{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Fang; Forbes, Scott [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada); Ramachandran, Krishna Kumar [Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2 (Canada); Mozharivskyj, Yurij, E-mail: mozhar@mcmaster.ca [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada)

    2015-11-25

    The Cr{sub 5}B{sub 3}-type Ta{sub 5}Si{sub 3} phase was prepared by arc-melting, while the Cr{sub 5}B{sub 3}-type Ta{sub 5}Ge{sub 3} one was synthesized through sintering at 1000 °C. X-ray single crystal diffraction was employed to elucidate their structure. According to the magnetization measurements, both Ta{sub 5}Si{sub 3} and Ta{sub 5}Ge{sub 3} are Pauli paramagnets, with Ta{sub 5}Ge{sub 3} showing a Curie-Weiss-like paramagnetic behavior at low temperatures likely due to presence of paramagnetic impurity. Both Ta{sub 5}Si{sub 3} and Ta{sub 5}Ge{sub 3} display a very low electrical resistivity from 2 to 300 K. The resistivity is constant below 20 K, but displays a positive temperature coefficient above 20 K. Electronic structure calculations with the TB-LMTO-ASA method support the metallic character of the two phases and suggest that the bonding is optimized in both phases. - Highlights: • Synthesis of Cr{sub 5}B{sub 3}-type Ta{sub 5}Si{sub 3} and Ta{sub 5}Ge{sub 3} phases with high purity by arc-melting and sintering, respectively. • Magnetization data and electrical resistivity of the Cr{sub 5}B{sub 3}-type Ta{sub 5}Si{sub 3} and Ta{sub 5}Ge{sub 3} phases. • Crystal and electronic structure analysis for Ta{sub 5}Si{sub 3} and Ta{sub 5}Ge{sub 3} phase by X-ray diffraction and TB-LMTO-ASA calculations.

  14. Specific heat of PrNi{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Kim-Ngan, N.H. [Center for Solid State Physics, Sw Filip 5, 31-150, Krakow (Poland)]|[Van der Waals-Zeeman Laboratorium, Universiteit van Amsterdam, Valckenierstraat 65, 1018 XE, Amsterdam (Netherlands); Radwanski, R.J. [Center for Solid State Physics, Sw Filip 5, 31-150, Krakow (Poland)]|[Inst. Physics and Informatics, Pedagogical University, 30-084, Krakow (Poland); Kayzel, F.E. [Van der Waals-Zeeman Laboratorium, Universiteit van Amsterdam, Valckenierstraat 65, 1018 XE, Amsterdam (Netherlands); Franse, J.J.M. [Van der Waals-Zeeman Laboratorium, Universiteit van Amsterdam, Valckenierstraat 65, 1018 XE, Amsterdam (Netherlands)

    1995-02-09

    Specific-heat measurements have been performed on single-crystalline PrNi{sub 5} from 1.3 to 250 K, in order to evaluate the contribution of the Pr subsystem. PrNi{sub 5} does not order magnetically down to the lowest temperatures as crystalline-electric-field (CEF) interactions, producing the non-magnetic singlet ground state {Gamma}{sub 4}, dominate the exchange interactions. Analysis of the specific heat unambiguously establishes the position of the two lowest excited levels at 33.7 K ({Gamma}{sub 1}) and 45.7 K ({Gamma}{sub 6}) which levels cannot be observed in inelastic-neutron-scattering experiments. A set of CEF parameters of the Pr{sup 3+} ion in the f{sup 2} configuration has been evaluated that gives the best account for all known experimental results of this compound. ((orig.)).

  15. Hard X-ray MCD in GdNi/sub 5/ and TbNi/sub 5/ single crystals

    CERN Document Server

    Galera, R M

    1999-01-01

    XMCD experiments have been performed at the R L/sub 2,3/ and Ni K- edges on magnetically saturated single crystals of GdNi/sub 5/ and Tb Ni/sub 5/ ferromagnetic compounds. The spectra present huge and well structured dichroic $9 signals at both the R L/sub 2,3/ and the Ni K- edges. Structures from the quadrupolar (2p to 4f) transitions are clearly observed at the R L/sub 2,3/-edges. Though Ni is not magnetic, large intensities, up to 0.4, are measured at the $9 Ni K- edge. The Ni K-edge XMCD shows a three-peak structure which intensities dependent on the rare earth. (7 refs).

  16. PULSAR: A High-Repetition-Rate, High-Power, CE Phase-Locked Laser for the J.R. Macdonald Laboratory at Kansas State University

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Itzhak, Itzik [Kansas State Univ., Manhattan, KS (United States). Physics Dept. J.R. Macdonald Lab.; Carnes, Kevin D. [Kansas State Univ., Manhattan, KS (United States). Physics Dept. J.R. Macdonald Lab.; Cocke, C. Lew [Kansas State Univ., Manhattan, KS (United States). Physics Dept. J.R. Macdonald Lab.; Fehrenbach, Charles W. [Kansas State Univ., Manhattan, KS (United States). Physics Dept. J.R. Macdonald Lab.; Kumarappan, Vinod [Kansas State Univ., Manhattan, KS (United States). Physics Dept. J.R. Macdonald Lab.; Rudenko, Artem [Kansas State Univ., Manhattan, KS (United States). Physics Dept. J.R. Macdonald Lab.; Trallero, Carlos [Kansas State Univ., Manhattan, KS (United States). Physics Dept. J.R. Macdonald Lab.

    2014-05-09

    This instrumentation grant funded the development and installation of a state-of-the-art laser system to be used for the DOE funded research at the J.R. Macdonald Laboratory at Kansas State University. Specifically, we purchased a laser based on the KMLABs Red-Dragon design, which has a high repetition rate of 10-20 kHz crucial for multi-parameter coincidence measurements conducted in our lab. This laser system is carrier-envelope phase (CEP) locked and provides pulses as short as 21 fs directly from the amplifier (see details below). In addition, we have developed a pulse compression setup that provides sub 5 fs pulses and a CEP tagging capability that allows for long measurements of CEP dependent processes.

  17. Testing relativity again, laser, laser, laser, laser

    NARCIS (Netherlands)

    Einstein, A.

    2015-01-01

    laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser,

  18. FS65 Disposition Option Report

    Energy Technology Data Exchange (ETDEWEB)

    Wenz, Tracy R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-25

    This report outlines the options for dispositioning the MOX fuel stored in FS65 containers at LANL. Additional discussion regarding the support equipment for loading and unloading the FS65 transport containers is included at the end of the report.

  19. Investigation of possible fs-LASIK induced retinal damage

    Science.gov (United States)

    Schumacher, S.; Sander, M.; Stolte, A.; Doepke, C.; Baumgaertner, W.; Lubatschowski, H.

    2006-02-01

    Rapid development of new laser technologies enabled the application of ultra short lasers in refractive surgery. Focused ultra short laser pulses in near-infrared spectral range can generate a laser induced breakdown (LIB) in the cornea, which will disrupt the tissue. Cutting depth and position can be established by varying the laser focus. The fs-LASIK technique allows both flap and lenticule to be formed by using fs-pulses without the presence of any mechanical impact. During the cutting process not all of the pulse energy is deposited into the cornea; approximately half of the remaining energy propagates through the eye and reaches the retina. Though defocused, the transmitted energy can still induce damage to the retina due to absorption by the retinal pigment epithelium and the transfer of thermal energy to surrounding tissue. The fs-LASIK process was simulated with two laser systems; one continous-wave and one in the fs-regime. For the simulation the exposure time and focusing numerical aperature which defines the retinal spot size were varied. The Damage thresholds of the laser beam exposed eyes were determined in terms of ophthalmoscopic and histopathologic observations.

  20. Parafermionic theory with the symmetry Z{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Dotsenko, Vladimir S. E-mail: dotsenko@lpthe.jussieu.fr; Jacobsen, Jesper Lykke E-mail: jacobsen@ipno.in2p3.fr; Santachiara, Raoul E-mail: santachiara@lpthe.jussieu.fr

    2003-04-28

    A parafermionic conformal theory with the symmetry Z{sub 5} is constructed, based on the second solution of Fateev-Zamolodchikov for the corresponding parafermionic chiral algebra. The primary operators of the theory, which are the singlet, doublet 1, doublet 2, and disorder operators, are found to be accommodated by the weight lattice of the classical Lie algebra B{sub 2}. The finite Kac tables for unitary theories are defined and the formula for the conformal dimensions of primary operators is given.

  1. First Principles Investigation of the Mechanical, Thermodynamic and Electronic Properties of FeSn{sub 5} and CoSn{sub 5} Intermetallic Phases under Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wenming; Liu, Jing; Wang, Hong [China Building Materials Academy, Beijing (China); Zhang, Zhenwei [Linyi Academy of Technology Cooperation and Application, Linyi (China); Zhang, Liang [NeoTrident Technology Ltd., Shanghai (China); Bu, Yuxiang [Shandong University, Jinan (China)

    2017-02-15

    For guidance for developing Fe/Co-Sn-based anode materials for lithium-ion batteries, the mechanical, thermodynamic and electronic properties of FeSn{sub 5} and CoSn{sub 5} intermetallic phases under pressures ranging from 0 to 30 GPa have been investigated systematically using first-principles total-energy calculations within the framework of the generalized gradient approximation. The pressure was found to have significant effects on the mechanical, thermodynamic and electronic properties of these compounds. In the selected pressure range, CoSn{sub 5} has a more negative formation enthalpy than FeSn{sub 5}. Based on the calculated elastic constants, the bulk modulus, shear modulus, and Young's modulus were determined via the Viogt-Reuss-Hill averaging scheme. The variations of specific heats at constant volume for FeSn{sub 5} and CoSn{sub 5} in a wide pressure (0 - 30 GPa) and temperature (0 - 1000 K) range are also predicted from phonon density of states calculation. The calculated results suggested that both FeSn{sub 5} and CoSn{sub 5} are mechanically stable at pressure from 0 to 30 GPa. FeSn{sub 5} is dynamically stable at pressure up to, 30 GPa, at least, however, CoSn{sub 5} is dynamically stable no higher than 15 GPa.

  2. Unified model of plasma formation, bubble generation and shock wave emission in water for fs to ns laser pulses (Conference Presentation)

    Science.gov (United States)

    Liang, Xiao-Xuan; Freidank, Sebastian; Linz, Norbert; Paltauf, Günther; Zhang, Zhenxi; Vogel, Alfred

    2017-03-01

    We developed modeling tools for optical breakdown events in water that span various phases reaching from breakdown initiation via solvated electron generation, through laser induced-plasma formation and temperature evolution in the focal spot to the later phases of cavitation bubble dynamics and shock wave emission and applied them to a large parameter space of pulse durations, wavelengths, and pulse energies. The rate equation model considers the interplay of linear absorption, photoionization, avalanche ionization and recombination, traces thermalization and temperature evolution during the laser pulse, and portrays the role of thermal ionization that becomes relevant for T > 3000 K. Modeling of free-electron generation includes recent insights on breakdown initiation in water via multiphoton excitation of valence band electrons into a solvated state at Eini = 6.6 eV followed by up-conversion into the conduction band level that is located at 9.5 eV. The ability of tracing the temperature evolution enabled us to link the model of laser-induced plasma formation with a hydrodynamic model of plasma-induced pressure evolution and phase transitions that, in turn, traces bubble generation and dynamics as well as shock wave emission. This way, the amount of nonlinear energy deposition in transparent dielectrics and the resulting material modifications can be assessed as a function of incident laser energy. The unified model of plasma formation and bubble dynamics yields an excellent agreement with experimental results over the entire range of investigated pulse durations (femtosecond to nanosecond), wavelengths (UV to IR) and pulse energies.

  3. Photovoltaic effect in Bi{sub 2}TeO{sub 5} photorefractive crystal

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Ivan de, E-mail: ivan@ft.unicamp.brg; Capovilla, Danilo Augusto [GOMNI-Faculdade de Tecnologia/UNICAMP, Limeira (Brazil); Carvalho, Jesiel F.; Montenegro, Renata; Fabris, Zanine V. [Instituto de Física/Universidade Federal de Goiás, Goiânia (Brazil); Frejlich, Jaime [Instituto de Física “Gleb Wataghin”/UNICAMP, Campinas (Brazil)

    2015-10-12

    We report on the presence of a strong photovoltaic effect on nominally undoped photorefractive Bi{sub 2}TeO{sub 5} crystals and estimated their Glass photovoltaic constant and photovoltaic field for λ = 532 nm illumination. We directly measured the photovoltaic-based photocurrent in this material under λ = 532 nm wavelength laser light illumination and compared its behavior with that of a well known photovoltaic Fe-doped Lithium Niobate crystal. We also show the photovoltaic current to strongly depend on the polarization direction of light. Holographic diffraction efficiency oscillation during recording and the behavior of fringe-locked running holograms in self-stabilized experiments are also demonstrated here as additional indirect proofs of the photovoltaic nature of this material.

  4. A SrBPO sub 5 Eu sup 2 sup + storage phosphor for neutron imaging

    CERN Document Server

    Sakasai, K; Toh, K; Takahashi, H; Nakazawa, M; Kondo, Y

    2002-01-01

    The phosphor material SrBPO sub 5 :Eu sup 2 sup + has been investigated for two-dimensional imaging for a pulsed-neutron source. We found that this phosphor itself shows photostimulated luminescence by illumination with 635-nm laser light after neutron irradiation without adding any neutron-sensitive materials such as Gd. The neutron sensitivity was proportional to E sup - sup 0 sup . sup 5 , where E is the neutron energy. The neutron sensitivity was also increased by using enriched boron instead of natural boron. The S subgamma/S sub n ratio of this phosphor using enriched boron was better than that of a commercially available imaging plate, where S subgamma and S sub n are the gamma and neutron sensitivities, respectively. (orig.)

  5. Rapid Solidification of AB{sub 5} Hydrogen Storage Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gulbrandsen-Dahl, Sverre

    2002-01-01

    This doctoral thesis is concerned with rapid solidification of AB{sub 5} materials suitable for electrochemical hydrogen storage. The primary objective of the work has been to characterise the microstructure and crystal structure of the produced AB{sub 5} materials as a function of the process parameters, e.g. the cooling rate during rapid solidification, the determination of which has been paid special attention to. The thesis is divided into 6 parts, of which Part I is a literature review, starting with a short presentation of energy storage alternatives. Then a general review of metal hydrides and their utilisation as energy carriers is presented. This part also includes more detailed descriptions of the crystal structure, the chemical composition and the hydrogen storage properties of AB{sub 5} materials. Furthermore, a description of the chill-block melt spinning process and the gas atomisation process is given. In Part II of the thesis a digital photo calorimetric technique has been developed and applied for obtaining in situ temperature measurements during chill-block melt spinning of a Mm(NiCoMnA1){sub 5} hydride forming alloy (Mm = Mischmetal of rare earths). Compared with conventional colour transmission temperature measurements, this technique offers a special advantage in terms of a high temperature resolutional and positional accuracy, which under the prevailing experimental conditions were found to be {+-}29 K and {+-} 0.1 mm, respectively. Moreover, it is shown that the cooling rate in solid state is approximately 2.5 times higher than that observed during solidification, indicating that the solid ribbon stayed in intimate contact with the wheel surface down to very low metal temperatures before the bond was broken. During this contact period the cooling regime shifted from near ideal in the melt puddle to near Newtonian towards the end, when the heat transfer from the solid ribbon to the wheel became the rate controlling step. In Part III of the

  6. Kinetic generation of cis-C[sub 5]H[sub 5](CO)[sub 2]ReH[sub 2] from the reaction of C[sub 5]H[sub 5](CO)[sub 2]Re([mu]-H)Pt(H)(PPh[sub 3])[sub 2] with diphenylacetylene

    Energy Technology Data Exchange (ETDEWEB)

    Casey, C.P.; Tanke, R.S.; Hazin, P.N.; Kemnitz, C.R.; McMahon, R.J. (Univ. of Wisconsin, Madison (United States))

    1992-12-23

    Protonation of K[C[sub 5]H[sub 5](CO)[sub 2]ReH] with CF[sub 3]CO[sub 2]H at [minus]78[degrees]C produced a 65:35 mixture of cis-C[sub 5]H[sub 5](CO)[sub 2]ReH[sub 2] (cis-1) and trans-C[sub 5]H[sub 5](CO)[sub 2]ReH[sub 2] (trans-1). At 24[degrees]C, this mixture equilibrated to a 2:98 cis-1:trans-1 mixture. Reaction of C[sub 5]H[sub 5](CO)[sub 2]Re([mu]-H)Pt(H)(PPh[sub 3])[sub 2] (3-Ph) with diphenylacetylene at [minus]9[degrees]C initially produced an 84:16 cis-1:trans-1 mixture. Photolysis of trans-1 in a methylcyclohexane glass at 10 K gave a 40:60 cis-1:trans-1 photostationary state. cis-C[sub 5]H[sub 5](CO)[sub 2]ReHD (cis-1-HD) has an unusual intermediate magnitude of J[sub HD] = 6.5 Hz, which suggested the possibility that cis-1 might be in equilibrium with C[sub 5]H[sub 5](CO)[sub 2]Re([eta][sup 2]-HD) (cis-1-[eta][sup 2]-HD). Howevr, it was not possible to detect measurable amounts of C[sub 5]H[sub 5](CO)[sub 2]Re([eta][sup 2]-H[sub 2]) (cis-1-[eta][sup 2]-H[sub 2]) by IR spectroscopy. 30 refs., 1 fig., 2 tabs.

  7. Nonlinear side effects of fs pulses inside corneal tissue during photodisruption

    Science.gov (United States)

    Heisterkamp, A.; Ripken, T.; Mamom, T.; Drommer, W.; Welling, H.; Ertmer, W.; Lubatschowski, H.

    In order to evaluate the potential for refractive surgery, fs laser pulses of 150-fs pulse duration were used to process corneal tissue of dead and living animal eyes. By focusing the laser radiation down to spot sizes of several microns, very precise cuts could be achieved inside the treated cornea, accompanied with minimum collateral damage to the tissue by thermal or mechanical effects. During histo-pathological analysis by light and transmission electron microscopy considerable side effects of fs photodisruption were found. Due to the high intensities at the focal region several nonlinear effects occurred. Self-focusing, photodissociation, UV-light production were observed, leading to streak formation inside the cornea.

  8. Electrical resistivity of CeTIn{sub 5} (T=Rh, Ir) under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Muramatsu, Takaki; Kobayashi, Tatsuo C.; Shimizu, Katsuya; Amaya, Kiichi; Aoki, Dai; Haga, Yoshinori; Onuki, Yoshichika

    2003-05-15

    We have studied the superconducting properties of CeTIn{sub 5} (T=Rh, Ir) under high pressures by means of electrical resistivity measurements and determined the pressure-temperature phase diagrams for the superconducting transition. For both systems, the superconductivity exists in a wide pressure range, 1.5{<=}P{<=}6.5 GPa for CeRhIn{sub 5} and 0{<=}P{<=}5.2 GPa for CeIrIn{sub 5}.

  9. Magnetic anisotropy and high-field magnetization process of CeCo[sub 5

    Energy Technology Data Exchange (ETDEWEB)

    Bartashevich, M.I. (Tokyo Univ. (Japan). Inst. for Solid State Physics (ISSP)); Goto, T. (Tokyo Univ. (Japan). Inst. for Solid State Physics (ISSP)); Radwanski, R.J. (Centre for Solid State Physics, Krakow (Poland)); Korolyov, A.V. (Inst. of Metal Physics, Ekaterinburg (Russian Federation))

    1994-03-01

    The magnetization process of single-crystalline CeCo[sub 5] has been measured at various temperatures from 4.2 to 300 K in high magnetic fields up to 40 T. The uniaxial magnetocrystalline anisotropy constant K[sub 1] is found to be about 35% higher than that of YCo[sub 5]. The magnetization anisotropy reaches p = 0.12 at 4.2 K, which is also higher than that of YCo[sub 5]. Both the anisotropies decrease with increasing temperature. These experimental results indicate that Ce in CeCo[sub 5] is in a mixed-valence state. (orig.)

  10. Ultrafast optical spectroscopy of quasi one dimensional Ta{sub 2}NiSe{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Mor, Selene; Herzog, Marc; Monney, Claude; Staehler, Julia; Wolf, Martin [Fritz-Haber-Institut der MPG, Dept. of Phys. Chem., Berlin (Germany)

    2015-07-01

    Ta2NiSe5 is a layered compound in which atomic chains are aligned in the layers, forming a quasi one dimensional crystal structure. At 328 K, the system shows a structural change, which is accompanied by an electronic phase transition from a semiconductor to an excitonic insulator, with an estimated energy gap of about few hundreds millielectronvolts. Our aim is to unveil the microscopic mechanisms underlying the phase transition in Ta{sub 2}NiSe{sub 5}. The system is excited with a femtosecond Ti:sapphire fundamental laser pulse and the mid-infrared (MIR) transient optical response is monitored by ultrafast optical spectroscopy. We observe a fast rise of transient reflectivity, which decays exponentially. This incoherent response is superimposed by a coherent phonon oscillation. A preliminary study with white light (WL) probe beam shows that low repetition rate is mandatory to study the response of the photoexcited system. The analysis unveils the presence of two phonons at 3 and 4 THz, that dominate at high (HT) and low (LT) temperature, respectively. We study the time evolution of the two phonons in the LT phase. We reveal a finite lifetime for the LT phase phonon, whose amplitude decays within few picoseconds, while the HT phase phonon amplitude remains almost constant. The picture is supported by temperature-dependent Raman spectroscopy.

  11. Rapid determination of wastewater BOD{sub 5} using a spectrophotometric technique; Una metodologia spettrofotometrica per la determinazione rapida del BOD{sub 5} dei liquami

    Energy Technology Data Exchange (ETDEWEB)

    De Rosa, S. [Montalto Uffugo Univ. della Calabria, Montalto Uffugo, Cosenza (Italy). Dipt di Difesa del Suolo

    2000-10-01

    Biochemical oxygen demand (BOD{sub 5}) is one of the most widely used measurement of the biodegradable content of wastewater. This parameter is adopted both in the present environmental legislation to control water pollution and in the design of the units of wastewater treatment plants. The conventional BOD{sub 5} test takes 5 days as it involves the direct measure of oxygen consumption by microorganisms in this period of time. Some innovative techniques have been developed in order to reduce this long response time, but their substrate specific results joined with complex operational requirements limit their utilization to particular cases (Riedel et al. 1990; Brookman 1996; Reynolds, 1997). In the present work the results of experimental tests, performed in order to evaluate the possibility of determining BOD{sub 5} by a more rapid analytical technique, are presented. By means of a relatively cheap and simple spectrophotometric technique using Fluorescein Diacetate it is possible to obtain BOD{sub 5} values in few hours and with a precision comparable to the conventional methods. [Italian] Il BOD{sub 5} e' uno dei parametri piu' frequentemente utilizzati per caratterizzare il carico inquinante di un refluo organico. La sua determinazione e' generalmente ottenuta come misura diretta della quantita' di ossigeno sottratto in 5 giorni dai batteri all'ambiente circostante. Alcune tecniche analitiche alternative a quelle convenzionali sono state proposte per ridurre i tempi necessari alla determinazione del BOD{sub 5}, ma la loro risposta specifica per determinati substrati e la relativa complessita' di applicazione ne hanno limitato l'impiego a casi particolari (Riedel et al. 1990; Brookman 1996; Reynolds, 1997). Nell'ambito del presente lavoro vengon descritti i risultati di una serie di sperimentazioni condotte per verificare la possibilita' di ridurre i tempi necessari alla determinazione del BOD{sub 5} di campioni di

  12. Epitaxial growth and dielectric properties of Bi sub 2 VO sub 5 sub . sub 5 thin films on TiN/Si substrates with SrTiO sub 3 buffer layers

    CERN Document Server

    Lee, H Y; Choi, B C; Jeong, J H; Joseph, M; Tabata, H; Kawai, T

    2000-01-01

    Bi sub 2 VO sub 5 sub . sub 5 (BVO) thin films were epitaxially grown on SrTiO sub 3 /TiN/Si substrates by using pulsed laser ablation. A TiN thin film was prepared at 700 .deg. C as a bottom electrode. The TiN film exhibited a high alpha axis orientation and a very smooth morphology. Before the preparation of the BVO thin film, a crystallized SrTiO sub 3 thin film was deposited as a buffer layer on TiN/Si. The BVO thin film grown at a substrate temperature at 700 .deg. C and an oxygen pressure of 50 mTorr was found to be epitaxial along the c-axis. Also, BVO films were observed to have flat surfaces and the step-flow modes. The dielectric constant of the BVO film on STO/TiN/Si was constant at about 8 approx 4 in the applied frequency range between 10 sup 2 and 10 sup 6 Hz.

  13. Magnetic properties and magnetic entropy change of LaFe sub 1 sub 1 sub . sub 5 Si sub 1 sub . sub 5 H sub y interstitial compounds

    CERN Document Server

    Chen Yuan Fu; Shen Bao Gen; Hu Feng Xia; Sun Ji Rong; Wang Guang Jun; Cheng Zhao Hua

    2003-01-01

    LaFe sub 1 sub 1 sub . sub 5 Si sub 1 sub . sub 5 H sub y interstitial compounds have been prepared by hydrogen absorption and subsequent desorption. The Curie temperatures are easily tunable for a wide temperature range from approx 195 to approx 340 K by hydrogen content. The maximal magnetic entropy changes, under a magnetic field change of 0-5 T, are as large as 16.8- 20.5 J kg sup - sup 1 K sup - sup 1 , exceeding that of Gd (|DELTA S| approx 9.8 J kg sup - sup 1 K sup - sup 1 at T sub C = 293 K) by 70-110% in the vicinity of room temperature. The large magnetic entropy change of all hydrides may be attributed to the first-order itinerant-electron metamagnetic transition confirmed by the Arrott plots. Large |DELTA S|, convenient adjustment of T sub C and small thermal and magnetic hystereses, make LaFe sub 1 sub 1 sub . sub 5 Si sub 1 sub . sub 5 H sub y interstitial hydrides promising candidates for magnetic refrigerants in the corresponding temperature range. (letter to the editor)

  14. Renormalization group flows for the second Z{sub 5} parafermionic field theory

    Energy Technology Data Exchange (ETDEWEB)

    Dotsenko, Vladimir S. [Laboratoire de Physique Theorique et Hautes Energies, Unite Mixte de Recherche UMR 7589. Universite Pierre et Marie Curie, Paris VI (France) and CNRS, Universite Denis Diderot, Paris VII, Boite 126, Tour 25, 5eme etage, 4 place Jussieu, F-75252 Paris Cedex 05 (France)]. E-mail: dotsenko@lpthe.jussieu.fr; Estienne, Benoit [Laboratoire de Physique Theorique et Hautes Energies, Unite Mixte de Recherche UMR 7589. Universite Pierre et Marie Curie, Paris VI (France) and CNRS, Universite Denis Diderot, Paris VII, Boite 126, Tour 25, 5eme etage, 4 place Jussieu, F-75252 Paris Cedex 05 (France)]. E-mail: estienne@lpthe.jussieu.fr

    2006-12-28

    Using the renormalization group approach, the Coulomb gas and the coset techniques, the effect of slightly relevant perturbations is studied for the second parafermionic field theory with the symmetry Z{sub 5}. New fixed points are found and classified.

  15. The magnetic properties of the Ln sub 2 BaCuO sub 5

    Energy Technology Data Exchange (ETDEWEB)

    Salinas-Sanchez, A.; Saez-Puche, R.; Alario-Franco, M.A. (Universidad Complutense de Madrid (ES). Facultad de Ciencias Quimicas)

    1991-01-01

    The temperature dependence of the magnetic susceptibility for the different Ln{sub 2}BaCuO{sub 5} oxides (green phases) where Ln is Gd, Dy and Ho which after appears as impurities in the synthesis of high temperature superconductors, reveals the existence of antiferromagnetic ordering for both Cu and Ln sublattices. In the case of the isostructural Lu{sub 2}BaCuO{sub 5} the Cu{sup 2+} ions are ordered at about the same temperature found for Y{sub 2}BaCuO{sub 5}. The specific magnetic behavior of Nd{sub 2}BaCuO{sub 5} can be explained by considering its different structure-type.

  16. Automatic feature selection using FS-NEAT

    NARCIS (Netherlands)

    Ethembabaoglu, A.; Whiteson, S.

    2008-01-01

    This article describes a series of experiments used to analyze the FS-NEAT method on a double pole-balancing domain. The FS-NEAT method is compared with regular NEAT to discern its strengths and weaknesses. Both FS-NEAT and regular NEAT find a policy, implemented in a neural network, to solve the

  17. Electrochemical characterization of melt spun AB{sub 5} alloys for metal hydride batteries

    Energy Technology Data Exchange (ETDEWEB)

    Brateng, Randi

    2003-05-01

    This thesis is part of a larger research project where two metal hydride forming AB{sub 5} type alloys have been investigated. A slightly non-stoichiometric alloy with mischmetal on A-site and nickel, cobalt, manganese and aluminium on B-site has been characterized. The composition of this material, which will be referred to as Mm(NiCoMnA1){sub 5.15}, is close to the normal battery composition. The other alloy characterized is LaNi{sub 5} based, where nickel is partly substituted with tin. This material will later be referred to as La(NiSn){sub 5}. These materials were produced by melt spinning to vary the cooling rate during solidification. The main purpose of the study has been to characterize the electrochemical properties related to battery performance. The production as well as the metallurgical and structural characterization of the materials were performed in another part of the project. For Mm(NiCoMnA1){sub 5.15} the unit cell volume was dependent on the cooling rate before heat treatment, while the unit cell volume was almost independent of the cooling rate for La(NiSn){sub 5}. For both alloy compositions, the electrochemical properties seemed to change with varying cooling rate. The desorption equilibrium potential, the discharge capacity when discharging at a low current and the deterioration rate were found to be reduced with decreasing unit cell volume and increased with increasing unit cell volume, before heat treatment of Mm(NiCoMnA1){sub 5.15}. The self discharge rate was observed to be inversely proportional to the unit cell volume for this material. For not heat treated La(NiSn){sub 5}, produced at different cooling rates, the desorption equilibrium potential decreased when the self discharge rate and the discharge capacity increased after cycling for 300 cycles. The deterioration rate decreased when the desorption equilibrium potential was reduced for La(NiSn){sub 5}. The electrochemical parameters both before and after heat treatment of La(NiSn){sub

  18. The complex structure of liquid Cu{sub 6}Sn{sub 5} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Qin Jingyu; Gu Tingkun; Bian Xiufang [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Southern Campus, Jinan 250061 (China); Liu Hui [Shandong High Performance Computing Center, Shandong University, Southern Campus, Jinan 250061 (China)

    2009-04-15

    By applying ab initio molecular dynamics simulation to liquid Cu{sub 6}Sn{sub 5} alloy, the hetero-coordination tendency is discovered by Bathia-Thornton partial correlation functions and a chemical short-range parameter. However the local structural environment of Sn in l-Cu{sub 6}Sn{sub 5} alloy resembles that of liquid Sn by Voronoi analysis. A new feature, i.e. a subpeak in between the first and second peaks, is discovered by the present method which implies that topologically disordered {beta}-Sn-type structural units may exist in l-Cu{sub 6}Sn{sub 5} alloy. The local density states of electrons show that both Cu-Sn and Sn-Sn bonding exist in l-Cu{sub 6}Sn{sub 5} alloy. This work suggests that chemical short-range order between unlike atoms and self-coordination between Sn atoms coexists in l-Cu{sub 6}Sn{sub 5} alloy.

  19. Hydrothermal crystal growth, piezoelectricity, and triboluminescence of KNaNbOF{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kelvin B. [Department of Chemistry, Northwestern University, Evanston, IL 60208 (United States); Edwards, Bryce W. [Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611 (United States); Frazer, Laszlo; Lenferink, Erik J.; Stanev, Teodor K.; Stern, Nathaniel P. [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Nino, Juan C. [Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611 (United States); Poeppelmeier, Kenneth R., E-mail: krp@northwestern.edu [Department of Chemistry, Northwestern University, Evanston, IL 60208 (United States)

    2016-04-15

    Single crystals of the noncentrosymmetric KNaNbOF{sub 5} polymorph were grown for piezoelectric and triboluminescent measurements. Piezoelectric measurements yielded a d{sub 33} value of ±6.3 pCN{sup −1} and an effective electromechanical coupling coefficient of up to 0.1565 in the frequency range 1960–2080 kHz. Crystals of KNaNbOF{sub 5} were found to exhibit a strong triboluminscence effect visible to the naked eye as blue sparks when crystals are crushed. This triboluminescence effect is uncommon in that it is likely independent from both the piezoelectric effect and atmospheric electrical discharge. Instead, triboluminescence may originate from crystal defects or be related to an electroluminescence effect. - Graphical abstract: An optical emission visible to the naked eye as blue sparks is observed when KNaNbOF{sub 5} single crystals are fractured. - Highlights: • Single crystals of KNaNbOF{sub 5} were grown under hydrothermal conditions. • Piezoelectric and triboluminescent properties were characterized. • Piezoelectric measurements yielded a d{sub 33} value of ±pCN{sup −1}. • KNaNbOF{sub 5} exhibits strong triboluminscence visible to the naked eye as blue sparks.

  20. Relaxation phenomena in second-order nonlinearity of thermally and optically poled Nb{sub 2}O{sub 5}-TeO{sub 2} glasses

    Energy Technology Data Exchange (ETDEWEB)

    Yonesaki, Yoshinori; Hirao, Kazuyuki [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Yoshidahonmachi, Sakyo-ku, Kyoto (Japan); Tanaka, Katsuhisa [Department of Chemistry and Materials Technology, Faculty of Engineering and Design, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto (Japan)]. E-mail: katsu@ipc.kit.ac.jp; Narazaki, Aiko [National Institute of Advanced Industrial Science and Technology, Central 5, Higashi, Tsukuba, Ibaraki (Japan); Si, Jinhai [Photon Craft Project, ICORP, JST, Keihanna-plaza, Super-laboratory 2-6, Hikaridai, Seika-cho, Kyoto (Japan)

    2002-08-21

    We report on relaxation of second-harmonic intensity for optically poled 15Nb{sub 2}O{sub 5}x85TeO{sub 2} bulk glass as well as thermally/electrically poled 15Nb{sub 2}O{sub 5}x85TeO{sub 2} bulk glass doped with Na{sup +}. The second-order nonlinearity induced by the thermal poling is rather stable. The decay of second-harmonic intensity is barely observed at 50 deg. C at least 5 h after ceasing of thermal poling. The activation energy for relaxation of second-harmonic intensity obtained from temperature dependence of relaxation time is 77 kJ mol{sup -1}, which is somewhat larger than the activation energy for 20WO{sub 3}x80TeO{sub 2} glass doped with Na{sup +} reported previously by the present authors. For optical poling of the 15Nb{sub 2}O{sub 5}x85TeO{sub 2} bulk glass, fundamental and second-harmonic waves from a nanosecond pulsed Nd : YAG laser were utilized to induce second-order nonlinearity in the 15Nb{sub 2}O{sub 5}x85TeO{sub 2} glass. The magnitude of second-order nonlinearity is saturated after optical poling for about 400 s. The decay of second-harmonic intensity is very rapid compared with the case of thermal poling. We speculate that some charged defects formed by laser irradiation are responsible for the second-order nonlinearity induced by optical poling. (author)

  1. Ultrafast Gigantic Photo-Response in Charge-Ordered Organic Salt (EDO-TTF)2PF6 on 10-fs time scales

    Science.gov (United States)

    Itatani, J.; Rini, M.; Cavalleri, A.; Onda, K.; Ishikawa, T.; Ogihara, S.; Koshihara, S.; Shao, X. F.; Nakano, Y.; Yamochi, H.; Saito, G.; Schoenlein, R. W.

    The initial dynamics of photo-induced phase transition in charge-ordered organic salt (EDO-TTF)2PF6 was investigated using 10-fs near-infrared laser pulses. We observed sub-20-fs gigantic photo-responses (|∆R/R|>100%) due to intra-molecular vibration and a clear signature of a structural bottleneck (~50 fs) for the first time.

  2. Supersymmetric AdS{sub 5} solutions of type IIB supergravity without D3 branes

    Energy Technology Data Exchange (ETDEWEB)

    Couzens, Christopher [Department of Mathematics, King’s College London,The Strand, London, WC2R 2LS (United Kingdom)

    2017-01-10

    We analyse the most general bosonic supersymmetric solutions of type IIB supergravity whose metrics are warped products of five-dimensional anti-de Sitter space (AdS{sub 5}) with a five-dimensional Riemannian manifold M{sub 5}, where the five-form flux vanishes, while all remaining fluxes are allowed to be non-vanishing consistent with SO(4,2) symmetry. This completes the program of classifying all supersymmetric solutions of ten and eleven-dimensional supergravity with an AdS{sub 5} factor. We investigate the supersymmetry conditions in some special cases, and demonstrate how these are satisfied by a solution originally found in https://www.doi.org/10.1007/JHEP02(2015)040, utilising the method of non-Abelian T-duality.

  3. Structural, atomic Hirschfeld surface, magnetic and magnetocaloric properties of SmNi{sub 5} compound

    Energy Technology Data Exchange (ETDEWEB)

    Nouri, K., E-mail: nouri@icmpe.cnrs.fr [C.M.T.R, I.C.M.P.E, CNRS, Université Paris Est Créteil, UMR 7182, 2-8 rue Henri Dunant, F-94320 Thiais (France); Laboratoire des Sciences des Matériaux et de l' Environnement, Faculté des Sciences de Sfax- Université de Sfax, BP 1171, Sfax, 3018 (Tunisia); Jemmali, M. [Laboratoire des Sciences des Matériaux et de l' Environnement, Faculté des Sciences de Sfax- Université de Sfax, BP 1171, Sfax, 3018 (Tunisia); Chemistry Departement, College of Science and Arts at Ar-Rass, Qassim University, P.O. Box53 (Saudi Arabia); Walha, S. [Laboratoire des Sciences des Matériaux et de l' Environnement, Faculté des Sciences de Sfax- Université de Sfax, BP 1171, Sfax, 3018 (Tunisia); Zehani, K. [C.M.T.R, I.C.M.P.E, CNRS, Université Paris Est Créteil, UMR 7182, 2-8 rue Henri Dunant, F-94320 Thiais (France); Ben Salah, A. [Laboratoire des Sciences des Matériaux et de l' Environnement, Faculté des Sciences de Sfax- Université de Sfax, BP 1171, Sfax, 3018 (Tunisia); Bessais, L. [C.M.T.R, I.C.M.P.E, CNRS, Université Paris Est Créteil, UMR 7182, 2-8 rue Henri Dunant, F-94320 Thiais (France)

    2016-07-05

    The SmNi{sub 5} intermetallic compound has been investigated by arc-melting. Powder X-ray diffraction analysis and Rietveld refinement revealed that the sample crystallized in the hexagonal CaCu{sub 5}-type structure P6/mmm space group with the following lattice parameters: a = 4.9203 (1) Å, c = 3.9662 (1) Å. These lattice parameters for the compound are in good agreement with previous theoretical result and experimental data. The EDX analysis has been performed to confirm the composition of this compound. The chemical bonding in SmNi{sub 5} was analyzed using atomic Hirshfeld surfaces, and this analysis supports the presence of the structural elements and the coordination of Sm (1a), Ni (2c) and Ni (3 g). This study indicates the different types of interatomic interactions between the Sm and Ni atoms and the weak interactions between Sm–Sm atoms were also observed along the c axis. The magnetic properties and magnetocaloric effect (MCE) have been established by the magnetization and isothermal magnetization of different temperature measurements. The magnetization curve as a function of temperature shows a magnetic transition from ferromagnetic to paramagnetic state at the Curie temperature T{sub C} = 29 K. We have studied the MCE phenomena in the vicinity of magnetic phase transitions in terms of magnetic entropy change. The temperature dependence of the magnetization, the magnetic entropy changeΔS{sub M}, as well as the relative cooling power around the second-order magnetic transition and the Arrott plots for the alloys are reported. - Highlights: • The SmNi{sub 5} intermetallic compound has been investigated by arc-melting. • The chemical bonding in SmNi{sub 5} was analyzed using atomic Hirshfeld surfaces. • The second order magnetocaloric material SmNi{sub 5} is investigated.

  4. Lithium insertion in V{sub 2}O{sub 5}, M{sub x}V{sub 2}O{sub 5} (M = Fe, Cr, Al, La) mixed oxides; Insertion du lithium dans les oxydes mixtes de V{sub 2}O{sub 5}, M{sub x}V{sub 2}O{sub 5} (M = Fe, Cr, Al, La)

    Energy Technology Data Exchange (ETDEWEB)

    Gregoire, G.; Pecquenard, B.; Baffier, N. [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France). Laboratoire de Chimie Appliquee de l`Etat Solide; Soudan, P.; Farcy, J.; Pereira-Ramos, J.P. [Centre National de la Recherche Scientifique (CNRS), 94 - Ivry-sur-Seine (France). Laboratoire d`Electrochimie Catalyse et Synthese Organique

    1996-12-31

    V{sub 2}O{sub 5} based compounds are interesting low potential materials for rechargeable cathodes of lithium electrochemical generators. However, the ionic conductivity and the reversibility of electrochemical cycling of V{sub 2}O{sub 5} are limited by the possibilities of lithium insertion. This work shows that the doping of vanadium pentoxide by a M{sup 3+} trivalent transition element (M Fe, Al, Cr or La) allows to intercalate a more important amount of lithium and to improve the behaviour of the material during cycling. These materials of M{sub 0.11}V{sub 2}O{sub 5.16} formula are obtained by sol-gel synthesis. the electrochemical study of the Fe compound has shown that it is a mixed oxide with a behaviour similar to V{sub 2}O{sub 5}. The maximum capacity is of about 2 F/mole in the case of Fe, Al and Cr compounds and of about 1.7 F/mole in the case of La. The structural evolution of the Fe compound has been followed during the chemical insertion of Li and the same succession of phases ({alpha}, {epsilon}, {delta} and {gamma}) is observed as in Li{sub x}V{sub 2}O{sub 5} compounds but with a delay. The occurrence of the {gamma} phase, in particular, which is involved in recharging problems is delayed thanks to the (Fe-O){sub n} chains perpendicular to the (V{sub 2}O{sub 5}){sub n} layers. Abstract only. (J.S.) 3 refs.

  5. Preparation, structure and photoluminescence of nanoscaled-Nd: Lu{sub 3}Al{sub 5}O{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Ding Lihua [Anhui Provincial Key Lab of Optical Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Zhang, Qingli, E-mail: zql@aiofm.ac.cn [Anhui Provincial Key Lab of Optical Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Luo Jianqiao; Liu Wenpeng [Anhui Provincial Key Lab of Optical Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Zhou Wenlong [Anhui Provincial Key Lab of Optical Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Yin Shaotang [Anhui Provincial Key Lab of Optical Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China)

    2011-10-20

    Highlights: > Nd:Lu{sub 3}Al{sub 5}O{sub 12} (Nd:LuAG) nano-crystalline was synthesized by co-precipitation method, its polycrystalline phase can be formed above 900 deg. C and its structure was refined by Rietveld method. > From the point of structure, studies on the difference of crystal field interaction between Nd:LuAG and Nd:YAG were carried out. > Compared with Nd:YAG, Nd:LuAG has broader absorption FWHM at 808 nm, longer fluorescence lifetime and larger emission cross section. - Abstract: Nd:Lu{sub 3}Al{sub 5}O{sub 12} (Nd:LuAG) nano-crystalline was synthesized by co-precipitation method. Its phase transformation, structure, absorption and photoluminescence properties were studied. The Nd:LuAG polycrystalline phase is formed above 900 deg. C and its particle sizes are in the range of 18-36 nm. The structure of Nd:LuAG was refined by Rietveld method. The lattice parameters and the distortion of Lu{sup 3+}-O{sup 2-} polyhedron in Nd:LuAG are larger than that of in pure LuAG. Because the distortion of Lu{sup 3+}-O{sup 2-} polyhedron is larger than that of Y{sup 3+}-O{sup 2-} polyhedron in YAG and the distance of Lu{sup 3+}-O{sup 2-} is smaller than that of Y{sup 3+}-O{sup 2-} in YAG, Nd{sup 3+} in LuAG experiences a stronger crystal field effect, which is proved by the crystal field strength and the chemical environment parameter. The absorption spectrum shows that Nd:LuAG has a broad absorption band at 808 nm with FWHM above 6 nm, which is favorable for improving laser efficiency. The fluorescence lifetime from {sup 4}F{sub 3/2} {yields} {sup 4}I{sub 11/2} transition is 320 {mu}s and longer than that of Nd:YAG. The longer lifetime is propitious to energy storage. The emission cross section at 1064 nm is 2.89 x 10{sup -19} cm{sup 2}, taking into account the Boltzmann distribution of the excited state. The emission cross section in Nd:LuAG is also larger than that of Nd:YAG, which is useful for laser operation. All results indicate that Nd:LuAG is a promising

  6. Use of the Femtosecond Lasers in Ophthalmology

    Science.gov (United States)

    Roszkowska, Anna M.; Urso, Mario; Signorino, Alberto; Aragona, Pasquale

    2018-01-01

    Femtosecond laser (FSL) is an infrared laser with a wavelength of 1053 nm. FS laser works producing photodisruption or photoionization of the optically transparent tissue such as cornea. Currently FS lasers have a wide range of applications in ophthalmic surgery. They are used above all in corneal surgery in refractive procedures and keratoplasty, and recently in cataract surgery. The use of the FSL in corneal refractive surgery includes LASIK flap creation, astigmatic keratotomy, Femtosecond Lenticule Extraction (FLEx), Small Incision Lenticule Extraction (SMILE) and channels creation for implantation of the intrastromal corneal rings. As to the corneal grafting, the FS lasers are used in laser-assisted anterior and posterior lamellar keratoplasty and customized trephination in the penetrating keratoplasty. FS Laser Assisted Cataract Surgery (FLACS) includes capsulorrhexis and nuclear fragmentation that enhance safety and efficacy of the procedure.

  7. Fs = μs Fn

    Directory of Open Access Journals (Sweden)

    Bruno Ministro

    2016-09-01

    Full Text Available http://dx.doi.org/10.5007/1807-9288.2016v12n1p195 Fs = μs Fn é uma releitura a três vozes dos Homeóstatos de José-Alberto Marques. Partindo do desmembramento e recomposição digital do material sonoro, testam-se, com base nas possibilidades oferecidas pelo cruzamento entre a plasticidade vocal e as ferramentas digitais de manipulação, as potencialidades combinatórias que uma obra desta natureza encerra.

  8. Magnetic properties and inhomogeneous phase transition in (Fe sub x Co sub 0 sub . sub 5 sub - sub x)Pt sub 0 sub . sub 5 films

    CERN Document Server

    Jang, P W; Na, J G; Lee, S R

    1999-01-01

    (Fe sub x Co sub 0 sub . sub 5 sub - sub x)Pt sub 0 sub . sub 5 ternary thin films were deposited on glass substrates by using a dc sputtering method at room temperature and were subsequently annealed at 700 .deg. C in a high vacuum. A high degree of the (111) preferred orientation could be obtained in all the as-deposited films and was not destroyed, even though post annealing. The CoPt and the FePt binary alloys were completely mixed and had a L1 sub o -type ordered structure, as confirmed by single (222) peaks and by the linear variation of the lattice constant a sub o. The ordered structure of the FePt alloy was thought to have formed from the disordered structure by an inhomogeneous process, which was confirmed by the asymmetric peak shapes. The lattice parameter a sub o varied linearly with the Fe content while the coercivity showed a minimum value at the equiatomic composition of the Fe and the Co atoms.

  9. Thermoelectric power measurements in Fe doped La sub 0 sub . sub 6 sub 5 Ca sub 0 sub . sub 3 sub 5 MnO sub 3

    CERN Document Server

    Aslam, A; Zubair, M; Akhtar, M J; Nadeem, M

    2002-01-01

    We report measurements of the thermoelectric power (TEP) on the La sub 0 sub . sub 6 sub 5 Ca sub 0 sub . sub 3 sub 5 Mn sub 1 sub - sub x Fe sub x O sub 3 system for 0.00 <= x <= 0.07. The ferromagnetic and metallic transition temperatures are lowered and the TEP shows an increasingly positive trend with the addition of Fe. We also observe a clear magnetic contribution that manifests itself as a peak in the TEP close to the critical temperature. The activation energies determined from the TEP are seen to be insensitive to the Fe content. The data are interpreted firstly as showing a decrease in the density of active holes, i.e. holes that can participate in the hopping process, with increasing Fe content. Secondly the data suggest the role of magnetic scattering due to the clusters formed by the antiferromagnetically coupled Fe. Abrupt changes in the variation of the TEP are observed at the concentration region x approx 0.04 consistent with the hole density variation and with previously reported transp...

  10. Crystal structure, ionic conductivity and dielectric relaxation studies in the (C{sub 5}H{sub 10}N){sub 2}BiBr{sub 5} compound

    Energy Technology Data Exchange (ETDEWEB)

    Masmoudi, W., E-mail: masmoudiwafa1@yahoo.fr [Unite de Recherche de Chimie Industrielle et Materiaux, ENIS, BP 1173, Sfax (Tunisia); Kamoun, S.; Ayedi, H.F. [Unite de Recherche de Chimie Industrielle et Materiaux, ENIS, BP 1173, Sfax (Tunisia); Guidara, K. [Laboratoire de l' Etat Solide, Faculte des Sciences de Sfax 3018, Sfax (Tunisia)

    2012-07-01

    The synthesis and crystal structure of the bis (3-dimethylammonium-1-propyne) pentabromobismuthate(III) salt are given in the present paper. After an X-ray investigation, it has been shown that the title compound crystallizes at 298 K in a centrosymmetric monoclinic system, in the space group C{sub 2}/c with the following lattice parameters a=12.9034(3) A, b=19.4505(6) A, c=8.5188(2) A, {beta}=102.449(2). Not only were the impedance spectroscopy measurements of (C{sub 5}H{sub 10}N){sub 2}BiBr{sub 5} carried out from 209 Hz to 5 MHz over the temperature range of 318 K-373 K, but also its ac conductivity evaluated. Besides, the dielectric relaxation was examined using the modulus formalism. Actually, the near values of activation energies obtained from the impedance and modulus spectra confirms that the transport is of an ion hopping mechanism, dominated by the motion of the H{sup +} ions in the structure of the investigated material.

  11. Lattice dynamics, phase transitions and spin relaxation in [Fe(C{sub 5}H{sub 5}){sub 2}] PF{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Herber, R. H.; Felner, I.; Nowik, I., E-mail: nowik@vms.huji.ac.il [The Hebrew University, Racah Institute of Physics (Israel)

    2016-12-15

    The organometallic compound ferrocenium hexafluorophosphate, [Fe(C{sub 5}H{sub 5}){sub 2}] PF{sub 6}, has been studied by Mössbauer spectroscopy in the past, mainly to determine the crystal structure at high temperatures. Here we present studies at 95 K to 305 K and analyze the spectra in terms of spin relaxation theory which yields accurately the hyperfine interaction parameters and the spin-spin and spin-lattice relaxation rates in this paramagnetic compound. The spectral area under the resonance curve yields the recoil free fraction and thus the mean square of the vibration amplitude . One observes a large discontinuity in the slope of versus T at 210 K, indicative of a phase transition. The analysis of the spectra proves that the quadrupole interaction is small but certainly negative, ½e{sup 2}qQ = -0.12(2) mm/s, and causes the asymmetry observed in the spectra. The detailed analysis yields also, for the first time, the fluctuating effective magnetic hyperfine field, H {sub eff} = 180(50) kOe.

  12. Automatic feature selection using FS-NEAT

    OpenAIRE

    Ethembabaoglu, A.; Whiteson, S.

    2008-01-01

    This article describes a series of experiments used to analyze the FS-NEAT method on a double pole-balancing domain. The FS-NEAT method is compared with regular NEAT to discern its strengths and weaknesses. Both FS-NEAT and regular NEAT find a policy, implemented in a neural network, to solve the pole-balancing task by use of genetic algorithms. FS-NEAT, contrary to regular NEAT, uses a different starting population. Whereas regular NEAT networks start out with links between all the inputs an...

  13. The effect of preparation method on Pt/Nb{sub 2} O{sub 5} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Eleuterio, A.; Passos, F.B. [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Engenharia Quimica]. E-mail: fbpassos at telecom.uff.br; Aranda, D.A.G.; Schmal, M. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica. Dept, de Engenharia Quimica]. E-mail: donato@h2o.eq.ufrj.br; schmal@peq.coppe.ufrj.br; Santos, J.F.

    1998-06-01

    The use of the ion exchange method and the addition of lithium to Pt/NB{sub 2}O{sub 5} catalysts were investigated in this work, using techniques of temperature-programmed reduction, H{sub 2} and CO chemisorption, UV - Vis diffuse reflectance spectroscopy and the conversion of n-heptane as a catalytic test. The superficial precursor present after the calcination step is platinum oxide, as previously observed for Pt/Nb{sub 2} O{sub 5} catalysts prepared by the incipient wetness method. For some of the samples, auto reduction was observed during the calcination step, with the formation of low dispersion metallic platinum. The Pt/Nb{sub 5}O{sub 5} catalysts prepared by ion exchange showed a high yield of olefins, as compared to aromatics, in the conversion of n-heptane. However, a high yield of hydrogenolysis products was also observed. For some of the lithium-containing samples, there was a suppression of dehydrogenation and aromatization reactions, with an increase in central C-C bond hydrogenolysis. (author)

  14. Femtosecond and nanosecond pulsed laser deposition of silicon and germanium

    Energy Technology Data Exchange (ETDEWEB)

    Reenaas, Turid Worren [Department of Physics, Norwegian University of Science and Technology, 7491 Trondheim (Norway); Lee, Yen Sian [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Chowdhury, Fatema Rezwana; Gupta, Manisha; Tsui, Ying Yin [Department of Electrical and Computer Engineering, University of Alberta (Canada); Tou, Teck Yong [Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Selangor (Malaysia); Yap, Seong Ling [Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Kok, Soon Yie [Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Selangor (Malaysia); Yap, Seong Shan, E-mail: seongshan@gmail.com [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-11-01

    Highlights: • Ge and Si were deposited by fs and ns laser at room temperature and at vacuum. • Ion of 10{sup 4} ms{sup −1} and 30–200 eV was obtained for ns ablation for Ge and Si. • Highly energetic ions of 10{sup 5} ms{sup −1} with 2–7 KeV were produced in fs laser ablation. • Nanocrystalline Si and Ge were deposited by using fs laser. • Nanoparticles < 10 nm haven been obtained by fs laser. - Abstract: 150 fs Ti:Sapphire laser pulsed laser deposition of Si and Ge were compared to a nanosecond KrF laser (25 ns). The ablation thresholds for ns lasers were about 2.5 J cm{sup −2} for Si and 2.1 J cm{sup −2} for Ge. The values were about 5–10 times lower when fs laser were used. The power densities were 10{sup 8}–10{sup 9} W cm{sup −2} for ns but 10{sup 12} W cm{sup −2} for fs. By using an ion probe, the ions emission at different fluence were measured where the emitting ions achieving the velocity in the range of 7–40 km s{sup −1} and kinetic energy in the range of 30–200 eV for ns laser. The ion produced by fs laser was measured to be highly energetic, 90–200 km s{sup −1}, 2–10 KeV. Two ion peaks were detected above specific laser fluence for both ns and fs laser ablation. Under fs laser ablation, the films were dominated by nano-sized crystalline particles, drastically different from nanosecond pulsed laser deposition where amorphous films were obtained. The ions characteristics and effects of pulse length on the properties of the deposited films were discussed.

  15. D-instanton in AdS sub 5 and instanton in SYM sub 4

    CERN Document Server

    Chu, C S; Wu, Y Y

    1999-01-01

    Following the observation of Banks and Green that the D-instantons in AdS sub 5 correspond to the instantons in four-dimensional supersymmetric Yang-Mills theory, we study in more detail this correspondence for individual instantons. The supergravity solution for a D-instanton in AdS sub 5 is found using the ansatz used previously for D-instantons in flat space. We check that the actions and supersymmetries match between the D-instanton solution and the Yang-Mills instanton. Generalizing this result, we propose that any supergravity solution satisfying the ansatz corresponds to a (anti-) self-dual Yang-Mills configuration. Using this ansatz a family of identities for correlation functions in the supersymmetric Yang-Mills theory are derived.

  16. Next Generation Driver for Attosecond and Laser-plasma Physics.

    Science.gov (United States)

    Rivas, D E; Borot, A; Cardenas, D E; Marcus, G; Gu, X; Herrmann, D; Xu, J; Tan, J; Kormin, D; Ma, G; Dallari, W; Tsakiris, G D; Földes, I B; Chou, S-W; Weidman, M; Bergues, B; Wittmann, T; Schröder, H; Tzallas, P; Charalambidis, D; Razskazovskaya, O; Pervak, V; Krausz, F; Veisz, L

    2017-07-12

    The observation and manipulation of electron dynamics in matter call for attosecond light pulses, routinely available from high-order harmonic generation driven by few-femtosecond lasers. However, the energy limitation of these lasers supports only weak sources and correspondingly linear attosecond studies. Here we report on an optical parametric synthesizer designed for nonlinear attosecond optics and relativistic laser-plasma physics. This synthesizer uniquely combines ultra-relativistic focused intensities of about 1020 W/cm2 with a pulse duration of sub-two carrier-wave cycles. The coherent combination of two sequentially amplified and complementary spectral ranges yields sub-5-fs pulses with multi-TW peak power. The application of this source allows the generation of a broad spectral continuum at 100-eV photon energy in gases as well as high-order harmonics in relativistic plasmas. Unprecedented spatio-temporal confinement of light now permits the investigation of electric-field-driven electron phenomena in the relativistic regime and ultimately the rise of next-generation intense isolated attosecond sources.

  17. Composition and cycle life of multicomponent AB{sub 5} hydride electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Adzic, G.D.; Johnson, J.R.; Reilly, J.J.; McBreen, J.; Mukerjee, S. [Brookhaven National Lab., Upton, NY (United States); Kumar, M.P.S.; Zhang, W.; Srinivasan, S. [Texas A and M Univ., College Station, TX (United States). Center for Electrochemical Systems and Hydrogen Research

    1994-11-01

    Multicomponent AB{sub 5} hydrides are attractive replacements for the cadmium electrode in nickel -- cadmium batteries. The archetype compound of the AB{sub 5} alloy class is LaNi{sub 5}, but in a typical battery electrode mischmetal is substituted for La and Ni is substituted in part by variety of metals. While the effects of Ni substitution have been widely studied, relatively little effort has focused on the effect of La substitution. This paper deals with the effect on cycle life due to the increasing presence of Ce in the alloy series La{sub 1-x}Ce{sub x}Ni{sub 3.55}Co{sub .75}Mn{sub .4}Al{sub .3}. Alloys were characterized by the determination of pressure-composition relationships, molar volume of H and electrode cycle life. The effects due to lattice expansion are taken into account. It was concluded that the rate of loss of electrochemical capacity per charge/discharge cycle was significantly decreased due to the presence of Ce.

  18. Crystal field splitting in CePt{sub 5}. Magnetic analysis and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zinner, Martin; Praetorius, Christian; Fauth, Kai [Universitaet Wuerzburg, Experimentelle Physik II, 97074 Wuerzburg (Germany); Halbig, Benedikt; Bass, Utz; Geurts, Jean [Universitaet Wuerzburg, Experimentelle Physik III, 97074 Wuerzburg (Germany)

    2015-07-01

    The crystal electric field (CF) is an essential factor determining the paramagnetic response of rare earth ions in solids. In Ce intermetallics, Kondo screening can additionally modify the magnetic behavior and it may then prove difficult to disentangle the two. In the hexagonal surface intermetallic CePt{sub 5}, grown on Pt(111), we find two distinct sets of CF parameters which both account rather well for the anisotropic magnetic susceptibility and its temperature dependence. Different strengths of Kondo screening have to be assumed in the two cases in order to obtain quantitative agreement with experimental results. Discriminating between the two solutions requires an independent determination of the CF splitting. We shall report on our attempts to obtain this information from electronic Raman scattering. Raman signal is indeed even obtained from CePt{sub 5} specimens with a thickness of just two unit cells. We shall discuss the identification of electronic Raman losses by comparison with LaPt{sub 5} as well as the dependence of the Raman features on temperature and thickness of the intermetallic film.

  19. Thin-film growth of the heavy-fermion superconductor CeCoIn{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Soroka, O.; Huth, M. [Physikalisches Inst., J.W. Goethe-Univ. Frankfurt (Germany)

    2007-07-01

    Thin films of CeCoIn{sub 5} were deposited on different substrates by using molecular beam epitaxy and found superconductive with transition temperatures about 2 K. Their transport properties are comparable with those of the bulk material and the resistivity shows typical heavy fermion behaviour. The growth characteristics were studied by means of X-ray diffraction and scanning tunneling microscopy and revealed (001)-oriented growth with pronounced island formation. Based on the chemical composition of the films obtained using energy dispersive X-ray analysis a ternary phase formation diagram was deduced. The heavy fermion compound CeCoIn{sub 5} is a member of a recently discovered layered heavy fermion family with general formula CeMIn{sub 5} (M=Co,Ir,Rh). These compounds exhibit many ground states that have been observed in f-electron systems, including paramagnetism, antiferromagnetism, exotic ambient-pressure and pressure induced superconductivity. There exists a relationship to the high-T{sub c} superconductors as well. The layered quasi-2D crystal structure of these materials and that of the high-T{sub c} cuprates share common features with regard to their spin-dependent electronic excitation spectrum. The most direct technique to investigate the spectrum of these excitations is tunneling spectroscopy which benefits strongly from well-defined surface as presented by epitaxial thin films. (orig.)

  20. Optical absorption and photoluminescence spectra of the ordered defect compound CuIn sub 3 Te sub 5

    CERN Document Server

    Rincon, C; Marin, G; Delgado, J M; Petroff, P M

    2003-01-01

    The optical properties of the ordered defect compound CuIn sub 3 Te sub 5 which crystallizes in a chalcopyrite-related structure have been studied by absorption and photoluminescence (PL) techniques. Optical absorption measurements show that the band gap energy E sub G varies from 1.078 to 1.040 eV between 10 and 300 K. It is found that the variation of E sub G with temperature is mainly due to the contribution of optical phonons with a characteristic energy of about 16 meV. The PL measurements, carried out between 4 and 100 K with laser excitation intensities in the range from 1 to 400 mW, reveal that the main PL band is due to a donor-acceptor recombination between donor and acceptor defect levels that have activation energies of 60 and 30 meV, respectively. These donor and acceptor states are tentatively assigned as originating from indium atoms on copper sites and copper vacancies, respectively.

  1. Development of a high power femtosecond laser

    CSIR Research Space (South Africa)

    Neethling, PH

    2010-10-01

    Full Text Available The Laser Research Institute and the CSIR National Laser Centre are developing a high power femtosecond laser system in a joint project with a phased approach. The laser system consists of an fs oscillator and a regenerative amplifier. An OPCPA...

  2. Sub-50 fs pulses around 2070 nm from a synchronously-pumped, degenerate OPO.

    Science.gov (United States)

    Rudy, Charles W; Marandi, Alireza; Ingold, Kirk A; Wolf, Stephen J; Vodopyanov, Konstantin L; Byer, Robert L; Yang, Lihmei; Wan, Peng; Liu, Jian

    2012-12-03

    We report generation of 48 fs pulses at a center wavelength of 2070 nm using a degenerate optical parametric oscillator (OPO) synchronously-pumped with a commercially available 36-MHz, femtosecond, mode-locked, Yb-doped fiber laser. The spectral bandwidth of the output is ~137 nm, corresponding to a theoretical, transform-limited pulse width of 33 fs. The threshold of the OPO is less than 10 mW of average pump power. By tuning the cavity length, the output spectrum covers a spectral width of more than 400 nm, limited only by the bandwidth of the cavity mirrors.

  3. Lasers.

    Science.gov (United States)

    Passeron, T

    2012-12-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  4. [Lasers].

    Science.gov (United States)

    Passeron, T

    2012-11-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  5. Evidence that cytochrome b{sub 5} acts as a redox donor in CYP17A1 mediated androgen synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Duggal, Ruchia [Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL (United States); Liu, Yilin [Department of Chemistry, Marquette University, Milwaukee, WI (United States); Gregory, Michael C.; Denisov, Ilia G. [Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL (United States); Kincaid, James R. [Department of Chemistry, Marquette University, Milwaukee, WI (United States); Sligar, Stephen G., E-mail: s-sligar@illinois.edu [Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL (United States); Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL (United States)

    2016-08-19

    Cytochrome P450 17A1 (CYP17A1) is an important drug target for castration resistant prostate cancer. It is a bi-functional enzyme, catalyzing production of glucocorticoid precursors by hydroxylation of pregnene-nucleus, and androgen biosynthesis by a second C−C lyase step, at the expense of glucocorticoid production. Cytochrome b{sub 5} (cyt b{sub 5}) is known to be a key regulator of the androgen synthesis reaction in vivo, by a mechanism that is not well understood. Two hypotheses have been proposed for the mechanism by which cyt b{sub 5} increases androgen biosynthesis. Cyt b{sub 5} could act as an allosteric effector, binding to CYP17A1 and either changing its selective substrate affinity or altering the conformation of the P450 to increase the catalytic rate or decrease unproductive uncoupling channels. Alternatively, cyt b{sub 5} could act as a redox donor for supply of the second electron in the P450 cycle, reducing the oxyferrous complex to form the reactive peroxo-intermediate. To understand the mechanism of lyase enhancement by cyt b{sub 5}, we generated a redox-inactive form of cyt b{sub 5}, in which the heme is replaced with a Manganese-protoporphyrin IX (Mn-b{sub 5}), and investigated enhancement of androgen producing lyase reaction by CYP17A1. Given the critical significance of a stable membrane anchor for all of the proteins involved and the need for controlled stoichiometric ratios, we employed the Nanodisc system for this study. The redox inactive form was observed to have no effect on the lyase reaction, while reactions with the normal heme-iron containing cyt b{sub 5} were enhanced ∼5 fold as compared to reactions in the absence of cyt b{sub 5}. We also performed resonance Raman measurements on ferric CYP17A1 bound to Mn-b{sub 5}. Upon addition of Mn-b{sub 5} to Nanodisc reconstituted CYP17A1, we observed clear evidence for the formation of a b{sub 5}-CYP17A1 complex, as noted by changes in the porphyrin modes and alteration in the proximal

  6. First-principles insights on electron transport in V{sub 2}O{sub 5} nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Anurag [Advanced Materials Research Group, Computational Nanoscience and Technology Laboratory, Atal Bihari Vajpayee-Indian Institute of Information Technology and Management, Gwalior, Madhya Pradesh 474015 (India); Chandiramouli, R., E-mail: rcmoulii@gmail.com [School of Electrical and Electronics Engineering, Shanmugha Arts Science Technology and Research Academy (SASTRA) University, Tirumalaisamudram, Thanjavur, Tamil Nadu 613 401 (India)

    2015-11-15

    Graphical abstract: - Highlights: • Band structure and electron transport in V{sub 2}O{sub 5} nanostructure are investigated using density functional theory. • V{sub 2}O{sub 5} nanostructure exhibits semiconducting behavior. • The electron density is observed to be more in oxygen sites than in vanadium sites. • The electron transport in V{sub 2}O{sub 5} molecular device can be tuned with the applied bias voltage. - Abstract: The present report is on the electron transport properties of V{sub 2}O{sub 5} nanostructures, investigated using density functional theory. As the band structure of V{sub 2}O{sub 5} exhibits semiconducting nature, the V{sub 2}O{sub 5} nanostructures are designed as molecular device and the transport properties are studied. The density of electrons is found to be more in the oxygen sites than in vanadium sites. The device density of states shows that the density of electrons in the energy intervals depends on the applied bias voltage. The transmission spectrum gives the insight on the transport property of V{sub 2}O{sub 5} molecular device. The bias voltage drives the electrons across V{sub 2}O{sub 5} scattering region, where the transmission along V{sub 2}O{sub 5} molecular device mainly depends on the bias voltage. The findings of the present work give insights to fine-tune the transport property of V{sub 2}O{sub 5} molecular device upon varying the bias voltage.

  7. Lifshitz transitions in RCo{sub 5} (R=Y,La) and in Osmium

    Energy Technology Data Exchange (ETDEWEB)

    Koudela, D.

    2007-02-20

    The aim of this thesis was to find Lifshitz transitions, which are topological changes of the Fermi surface. The materials under consideration had been YCo{sub 5} and LaCo{sub 5} and Osmium. In all cases the question arose, if the corresponding van Hove singularities are large enough to cause detectable anomalies in the elastic properties. To shift the van Hove singularities through the Fermi energy we used hydrostatic pressure, which is mimicked in the computations by decreasing the volume of the unit cell, where the ratio of the unit cell dimensions c/a is adjusted such that E{sub total}(V)=min{sub (c/a)}E{sub total}(V,c/a). In the case of YCo{sub 5} our calculations yield a first order Lifshitz transition. Here, an extraordinarily large peak in the spin-up part of the DOS, which is caused by a nearly dispersionless band in the hexagonal plane, crosses the Fermi level under a pressure of about 21 GPa. Thus, the spin-up 3d states become partly depopulated, which results in a drop of the total magnetic moment of 35%. Further, the transition results in a volume collapse of 1:4%. Though the volume collapse is isomorphic, it exhibits the following anisotropy: while the lattice constant in the hexagonal plane is almost smoothly contracting with increasing pressure, the lattice constant in c-direction collapses at the transition-pressure. Analogous calculations have been performed for the similar compound LaCo{sub 5}. Here as well we predict a first order Lifshitz transition, taking place at a pressure of about 23 GPa. Again we find a volume collapse under pres- sure together with a decrease of the magnetic moment. The relative volume change amounts to 1:3%. Like in YCo{sub 5}, the unit cell dimensions in the hexagonal plane are decreasing almost smoothly with pressure but in c-direction a jump occurs at the transition-pressure. Also the mechanism of the transition is the same than in YCo{sub 5}. For Osmium we find, that LDA reproduces the ground state volume very well

  8. Carbon monoxide hydrogenation on Co-Rh/Nb{sub 2}O{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Frydman, A.; Castner, D.G.; Campbell, C.T.; Schmal, M. [Universidade Federal, Rio de Janeiro (Brazil)

    1999-07-01

    Carbon monoxide hydrogenation activities and product distributions were investigated on a series of seven Co-Rh/Nb{sub 2}O{sub 5} catalysts: two monometallics Co and Rh supported on Nb{sub 2}O{sub 5} and five bimetallics Co-Rh supported on Nb{sub 2}O{sub 5} with similar Co (similar to 1.9 wt%) and variable Rh loadings (0.3-2.3 wt%). Catalytic performances at atmospheric pressure and 493 K were evaluated after low temperature reduction (LTR, 533-573 K) and after high temperature reduction (HTR, 773 K). Temperature-programmed reduction characterization revealed that the reduction temperature of the dominant Co phase on calcined catalysts, Co{sub 3}O{sub 4} strongly decreased as the Rh/Co bulk atomic ratio increased, while the reduction temperature on the Rh{sub 2}O{sub 3} phase (363 to 419 K) was not strongly influenced by the presence of Co{sub 3}O{sub 4}. It was observed that the activity decay effect caused by metal-support interaction was remarkably inhibited on the bimetallics with respect to the monometallics by comparing reaction rates after LTR and after HTR. The addition of Rh to the Co monometallic catalyst significantly altered the product distribution. An unusual promotion of the selectivity to long chain hydrocarbons was observed. Alcohol selectivity was enhanced up to 3.5 and 5.4% for ethanol and propanol, respectively, on the bimetallic catalyst with lower Rh concentration. The total CO hydrogenation reaction rate and the selectivity for methane were approximately constant as the Rh concentration on the bimetallics increased, suggesting that the metal surface area did not vary considerably on these catalysts.

  9. The kinematical AdS{sub 5}×S{sup 5} Neumann coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Bajnok, Zoltan [MTA Lendület Holographic QFT Group, Wigner Research Centre,P.O.B. 49, Budapest 114, H-1525 (Hungary); Janik, Romuald A. [Institute of Physics, Jagiellonian University,ul. Łojasiewicza 11, Kraków, 30-348 (Poland)

    2016-02-22

    For the case of two particles a solution of the string field theory vertex axioms can be factorized into a standard form factor and a kinematical piece which includes the dependence on the size of the third string. In this paper we construct an exact solution of the kinematical axioms for AdS{sub 5}×S{sup 5} which includes all order wrapping corrections w.r.t. the size of the third string. This solution is expressed in terms of elliptic Gamma functions and ordinary elliptic functions. The solution is valid at any coupling and we analyze its weak coupling, pp-wave and large L limit.

  10. Carbon monoxide hydrogenation on Co--Rh/Nb{sub 2}O{sub 5} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Frydman, A.; Castner, D.G.; Campbell, C.T.; Schmal, M.

    1999-11-15

    Carbon monoxide hydrogenation activities and product distributions were investigated here for the first time on a series of seven Co-Rh/Nb{sub 2}O{sub 5} catalysts: two monometallics Co and Rh supported on Nb{sub 2}O{sub 5} and five bimetallics CO-RH supported on NB{sub 2}O{sub 5} with similar Co ({approximately}1.9 wt%) and variable Rh loadings (0.3--2.3 wt%). Catalytic performances at atmospheric pressure and 493 K were evaluated after low temperature reduction (LTR, 533--573 K) and after high temperature reduction (HTR, 773 K). Temperature-programmed reduction characterization revealed that the reduction temperature of the dominant Co phase on calcined catalysts, Co{sub 3}O{sub 4}, strongly decreased as the Rh/Co bulk atomic ratio increased, while the reduction temperature of the RH{sub 2}O{sub 3} phase (363 to 419 K) was not strongly influenced by the presence of Co{sub 3}O{sub 4}. It was observed that the activity decay effect caused by metal-support interaction was remarkably inhibited on the bimetallics with respect to the monometallics by comparing reaction rate after LTR and after HTR. The addition of Rh to the Co monometallic catalyst significantly altered the product distribution. An unusual promotion of the selectivity to long chain hydrocarbons were observed. This promotion was more intense after HTR on the bimetallic catalysts, reaching {approximately}56% in the diesel fraction on the bimetallic catalyst with higher Rh concentration. Alcohol selectivity was enhanced up to 3.5 and 5.4% for ethanol and propanol, respectively, on the bimetallic catalyst with lower Rh concentration. The total CO hydrogenation reaction rate and the selectivity for methane were approximately constant as the Rh concentration on the bimetallics increased, suggesting that the metal surface area did not vary considerably on these catalysts. This agrees with hydrogen adsorption measurements on the bimetallic catalysts and with the XPS surface structural characterization of the

  11. USAARL NUH-60FS Acoustic Characterization

    Science.gov (United States)

    2016-11-01

    Aeromedical Research Laboratory 2Laulima Government Solutions, LLC 3Oak Ridge Institute for Science and Education United States Army Aeromedical Research...74.8 98.8 The NUH-60FS has been upgraded since the previous characterization, and these upgrades may have affected the ambient noise levels. The... ambient noise levels of the NUH-60FS while operating can be controlled via either software or hardware adjustments. The new data collected looked at the

  12. Ternary gallides RE{sub 4}Rh{sub 9}Ga{sub 5}, RE{sub 5}Rh{sub 12}Ga{sub 7} and RE{sub 7}Rh{sub 18}Ga{sub 11} (RE=Y, La-Nd, Sm, Gd, Tb). Intergrowth structures with MgCu{sub 2} and CaCu{sub 5} related slabs

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, Stefan; Rodewald, Ute C.; Poettgen, Rainer [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie; Janka, Oliver [Univ. Oldenburg (Germany). Inst. fuer Chemie

    2017-07-01

    Fourteen ternary gallides RE{sub 4}Rh{sub 9}Ga{sub 5}, RE{sub 5}Rh{sub 12}Ga{sub 7} and RE{sub 7}Rh{sub 18}Ga{sub 11} (RE=Y, La-Nd, Sm, Gd, Tb) were synthesized from the elements by arc-melting, followed by different annealing sequences either in muffle or induction furnaces. The samples were characterized through Guinier powder patterns and the crystal structures of Ce{sub 4}Rh{sub 9}Ga{sub 5}, Ce{sub 5}Rh{sub 12}Ga{sub 7}, Ce{sub 7}Rh{sub 18}Ga{sub 11}, Nd{sub 5}Rh{sub 10.44(4)}Ga{sub 8.56(4)}, Nd{sub 4}Rh{sub 9}Ga{sub 5} and Gd{sub 4}Rh{sub 9}Ga{sub 5} were refined from single crystal X-ray diffractometer data. The new gallides are the n=2, 3 and 5 members of the RE{sub 2+n} Rh{sub 3+3n} Ga{sub 1+2n} structure series in the Parthe intergrowth concept. The slabs of these intergrowth structures derive from the cubic Laves phase MgCu{sub 2} (Mg{sub 2}Ni{sub 3}Si as ternary variant) and CaCu{sub 5} (CeCo{sub 3}B{sub 2} as ternary variant). Only the Nd{sub 5}Rh{sub 10.44(4)}Ga{sub 8.56(4)} crystal shows Rh/Ga mixing within the Laves type slabs. Magnetic susceptibility measurements reveal Pauli paramagnetism for Y{sub 4}Rh{sub 9}Ga{sub 5} and Curie-Weiss paramagnetism for Gd{sub 4}Rh{sub 9}Ga{sub 5} and Tb{sub 4}Rh{sub 9}Ga{sub 5}. Low-temperature data show ferromagnetic ordering at T{sub C}=78.1 (Gd{sub 4}Rh{sub 9}Ga{sub 5}) and 55.8 K (Tb{sub 4}Rh{sub 9}Ga{sub 5}).

  13. Enhancement of soft X-ray emission from fs laser plasma by using mixture of molecule and atomic gases as cluster jet targets and its application for nanostructure imaging

    Energy Technology Data Exchange (ETDEWEB)

    Pikuz, T A; Faenov, A Ya; Fukuda, Y; Kando, M; Kotaki, H; Daito, I; Homma, T; Kawase, K; Kameshima, T; Kawachi, T; Bolton, P; Daido, H; Kimura, T; Tajima, T; Kato, Y; Bulanov, S V [Kansai Photon Science Institute (KPSI), Japan Atomic Energy Agency (JAEA), Kizugawa-city, Kyoto 619-0215 (Japan); Skobelev, I Yu; Gasilov, S V [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow (Russian Federation); Boldarev, A S; Gasilov, V A, E-mail: faenov.anatoly@jaea.go.j [Institute for Mathematical Modelling, Russian Academy of Sciences, Moscow (Russian Federation)

    2009-04-01

    Submicron scale clusters, produced by mixture of molecular (CO{sub 2}) and atomic (He) gases expanding from the specifically designed super-sonic nozzle, have been irradiated by femtosecond laser pulses in order to build up a bright debris-free soft X-ray source. Spectroscopy measurements showed that X-ray flux in the strongest oxygen spectral lines (He{sub b}eta at 665.7 eV and L{sub ya}lpha at 653.7 eV) produced by the plasma from gas mixture clusters is 2-8 times larger than in the case of using pure CO{sub 2} or N{sub 2}O clusters as targets and reaches values about 2.8x10{sup 10} ph/(sr centre dot pulse). Lines intensity and spatial dimension were measured from two observation point - along and perpendicular to the laser beam propagation directions. Images of 100 nm thick Mo foils in a wide field of view (cm{sup 2} scale) with high spatial resolution (700 nm) were obtained using LiF crystals as soft X-ray imaging detectors. Agreement between calculated and measured intensity of the image fragment which illustrates overlapping of Mo foil layers confirms accuracy of the plasma parameters measurements.

  14. First principle study of the electronic structure, Fermi surface, electronic charge density and optical properties of ThCu{sub 5}In and ThCu{sub 5}Sn single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Reshak, A.H. [Institute of complex systems, FFPW, CENAKVA-University of South Bohemia in CB, Nove Hrady 37333 (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Azam, Sikander, E-mail: sikander.physicst@gmail.com [Institute of complex systems, FFPW, CENAKVA-University of South Bohemia in CB, Nove Hrady 37333 (Czech Republic)

    2014-02-15

    The electronic structure, Fermi surface, electronic charge density and optical properties of ThCu{sub 5}In and ThCu{sub 5}Sn single crystals are studied. The calculations are based on the full potential-linearized augmented plane wave (FPLAPW) method. The exchange and correlation potential is treated by the local density approximation (LDA) and generalized-gradient approximation (GGA), in addition the Engel–Vosko (EV-GGA) formalism was also applied. The DFT calculations show that these compounds have metallic origin. The contribution of different bands was analyzed from total and partial density of states curves. The values of the density of states at Fermi energy (N(E{sub F})) for ThCu{sub 5}In (ThCu{sub 5}Sn) is 1.75 (1.63) states/eV unit cell. The bare electronic specific heat coefficient (γ) is found to be equal to 0.30 and 0.28 mJ/mol-K{sup 2} for ThCu{sub 5}In and ThCu{sub 5}Sn, respectively. The Fermi surface of ThCu{sub 5}In/ThCu{sub 5}Sn is composed of three/four bands crossing along the R–Γ direction. The bonding features are analyzed by using the electronic charge density contour in the (101) crystallographic plane and it shows the covalent character of Cu–Cu and Sn/In–Cu bonds. The optical properties were also calculated and analyzed. - Highlights: • The DFT-FPLAPW method used for calculating the properties of ThCu{sub 5}In and ThCu{sub 5}Sn compounds. • This study shows that the nature of the two compounds is metallic. • Crystallographic plane and it shows the covalent character of Cu–Cu and Sn/In–Cu bonds. • The optical properties were also calculated and analyzed. • The Fermi surface of ThCu{sub 5}In/ThCu{sub 5}Sn is composed of three/four bands crossing along the R–Γ direction.

  15. Magnetostructural transition in Fe{sub 5}SiB{sub 2} observed with neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Cedervall, Johan, E-mail: johan.cedervall@kemi.uu.se [Department of Chemistry - Ångström Laboratory, Uppsala University, Box 538, 751 21 Uppsala (Sweden); Kontos, Sofia [Department of Engineering Sciences, Uppsala University, Box 534, 751 21 Uppsala (Sweden); Hansen, Thomas C. [Institut Laue-Langevin, B.P. 156, 38042 Grenoble Cedex 9 (France); Balmes, Olivier; Martinez-Casado, Francisco Javier; Matej, Zdenek [MAX IV Laboratory, Lund University, Box 118, 221 00 Lund (Sweden); Beran, Premysl [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 25068 Rez (Czech Republic); Svedlindh, Peter; Gunnarsson, Klas [Department of Engineering Sciences, Uppsala University, Box 534, 751 21 Uppsala (Sweden); Sahlberg, Martin [Department of Chemistry - Ångström Laboratory, Uppsala University, Box 538, 751 21 Uppsala (Sweden)

    2016-03-15

    The crystal and magnetic structure of Fe{sub 5}SiB{sub 2} has been studied by a combination of X-ray and neutron diffraction. Also, the magnetocrystalline anisotropy energy constant has been estimated from magnetisation measurements. High quality samples have been prepared using high temperature synthesis and subsequent heat treatment protocols. The crystal structure is tetragonal within the space group I4/mcm and the compound behaves ferromagnetically with a Curie temperature of 760 K. At 172 K a spin reorientation occurs in the compound and the magnetic moments go from aligning along the c-axis (high T) down to the ab-plane (low T). The magnetocrystalline anisotropy energy constant has been estimated to 0.3 MJ/m{sup 3} at 300 K. - Highlights: • The crystal and magnetic structure of Fe{sub 5}SiB{sub 2} has been studied by diffraction. • At 172 K a spin reorientation occurs in the compound. • The magnetic moments are aligned along the c-axis at high T. • The magnetic moments are aligned in the ab-plane at low T. • The magnetocrystalline anisotropy energy constant has been estimated to 0.3 MJ/m{sup 3}.

  16. Phenomenology on a slice of AdS sub 5 xM supdelta spacetime

    CERN Document Server

    Davoudiasl, H; Hewett, J L

    2003-01-01

    We study the phenomenology resulting from backgrounds of the form AdS sub 5 xM supdelta, where M supdelta denotes a generic manifold of dimension subdelta>= 1, and AdS sub 5 is the slice of 5-dimensional anti-de Sitter space which generates the hierarchy in the Randall-Sundrum (RS) model. The delta additional dimensions may be required when the RS model is embedded into a more fundamental theory. We analyze two classes of delta-dimensional manifolds: flat and curved geometries. In the first case, the additional flat dimensions may accommodate localized fermions which in turn could resolve issues, such as proton decay and flavor, that were not addressed in the original RS proposal. In the latter case, the positive curvature of an S supdelta manifold with delta>1 can geometrically provide the 5-dimensional warping of the RS model. We demonstrate the key features of these two classes of models by presenting the background solutions, the spectra of the Kaluza-Klein (KK) gravitons, and their 4-dimensional coupling...

  17. Sub-5 nm nanostructures fabricated by atomic layer deposition using a carbon nanotube template

    Science.gov (United States)

    Woo, Ju Yeon; Han, Hyo; Kim, Ji Weon; Lee, Seung-Mo; Ha, Jeong Sook; Shim, Joon Hyung; Han, Chang-Soo

    2016-07-01

    The fabrication of nanostructures having diameters of sub-5 nm is very a important issue for bottom-up nanofabrication of nanoscale devices. In this work, we report a highly controllable method to create sub-5 nm nano-trenches and nanowires by combining area-selective atomic layer deposition (ALD) with single-walled carbon nanotubes (SWNTs) as templates. Alumina nano-trenches having a depth of 2.6 ∼ 3.0 nm and SiO2 nano-trenches having a depth of 1.9 ∼ 2.2 nm fully guided by the SWNTs have been formed on SiO2/Si substrate. Through infilling ZnO material by ALD in alumina nano-trenches, well-defined ZnO nanowires having a thickness of 3.1 ∼ 3.3 nm have been fabricated. In order to improve the electrical properties of ZnO nanowires, as-fabricated ZnO nanowires by ALD were annealed at 350 °C in air for 60 min. As a result, we successfully demonstrated that as-synthesized ZnO nanowire using a specific template can be made for various high-density resistive components in the nanoelectronics industry.

  18. Magnetic measurements on Tb{sub 5}Ge{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Haase, Ariane [Hochfeld-Magnetlabor Dresden, Forschungszentrum Dresden-Rossendorf, 01314 Dresden (Germany); Institut fuer Festkoerperphysik, TU Dresden, 01069 Dresden (Germany); Doerr, Mathias [Institut fuer Festkoerperphysik, TU Dresden, 01069 Dresden (Germany); Bartkowiak, Marek; Skourski, Yurii; Uhlarz, Marc [Hochfeld-Magnetlabor Dresden, Forschungszentrum Dresden-Rossendorf, 01314 Dresden (Germany); Daou, Ramzy [Hochfeld-Magnetlabor Dresden, Forschungszentrum Dresden-Rossendorf, 01314 Dresden (Germany); Max-Planck-Institut fuer Chemische Physik Fester Stoffe, 01187 Dresden (Germany); Rotter, Martin [University of Oxford, Department of Physics, Oxford (United Kingdom)

    2010-07-01

    Tb{sub 5}Ge{sub 3} is a weak antiferromagnet, which orders at 83 K. It crystallizes in Mn{sub 5}Si{sub 3}-type hexagonal structure with two different positions for the Tb{sup 3+} ions. The hexagonal ab-plane is the easy plane of magnetization. Magnetization and magnetostriction measurements have been done on a single crystal in static fields up to 30 T and in pulsed fields up to 50 T. In addition to the antiferromagnetic phase, three more phases were found in fields in the ab-plane at low temperatures. Surprisingly, the measurements along the b-axis do not resemble the a-axis properties which indicates an anisotropy in the hexagonal plane. Initial model calculations reveal the anisotropy of the magnetic exchange, which is dominant over the crystal electric field effect, as cause. The hard c-axis shows only one phase transition at 5 T followed by a nearly linear magnetization and magnetostriction slope which is attributed to a steady-going rotation of the moment.

  19. Insights on the origin of the Tb{sub 5}Ge{sub 4} magnetocaloric effect

    Energy Technology Data Exchange (ETDEWEB)

    Belo, J.H.; Barbosa, M.B. [IFIMUP and IN-Institue of Nanoscience and Nanotechnology, Departamento de Física da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre. 687, 4169-007 Porto (Portugal); Pires, A.L. [CFNUL - Centro de Física Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto, 2, 1649-003 Lisboa (Portugal); Costa, R.M.; Teixeira, J.G.V.; Silva, J. [IFIMUP and IN-Institue of Nanoscience and Nanotechnology, Departamento de Física da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre. 687, 4169-007 Porto (Portugal); Algarabel, P.A. [Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza and Consejo Superior de Investigaciones Cientificas, 50009 Zaragoza (Spain); Departamente de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza (Spain); Magen, C. [Instituto de Nanociencia de Aragón-ARAID, Universidad de Zaragoza, 50009 Zaragoza (Spain); Departamente de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza (Spain); Instituto de Nanociencia de Aragon, Universidad de Zaragoza, 50009 Zaragoza (Spain); Morellon, L. [Departamente de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza (Spain); Instituto de Nanociencia de Aragon, Universidad de Zaragoza, 50009 Zaragoza (Spain); Amaral, J.S. [IFIMUP and IN-Institue of Nanoscience and Nanotechnology, Departamento de Física da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre. 687, 4169-007 Porto (Portugal); CICECO, Universidade de Aveiro, 3810-193 Aveiro (Portugal); and others

    2017-05-15

    In this report the magnetic, atomic structures and spin-lattice coupling have been thoroughly studied through high magnetic field magnetometry, Synchrotron X-ray diffraction under applied magnetic field and magnetostriction measurements in the Tb{sub 5}Ge{sub 4} compounds. A field induced phase transition from an antiferromagnetic towards a ferromagnetic ordering was confirmed but with absence of structural transformation. This absence has been confirmed experimentally through synchrotron x-ray diffraction under applied field (up to 30 T). Moreover, this absence was explained via a thermodynamic free energy model: first principles calculations determined a large energy gap (ΔE=0.65 eV) between the two possible structures, O(I) and O(II). From magnetic and structural properties, a H-T phase diagram has been proposed for Tb{sub 5}Ge{sub 4}. Finally it was observed a large magnetostriction (up to 600 ppm) induced by ∆H=7 T.

  20. Crystallisation kinetics and optical properties of Ge sub 2 Sb sub 2 Te sub 5

    CERN Document Server

    Ruitenberg, G

    2001-01-01

    systems. E sub p , DELTA and GAMMA were determined before and after crystallisation of amorphous Ge sub 2 Sb sub 2 Te sub 5 films. From the numerical values of these parameters, it was concluded that the change in the reflectivity upon crystallisation is primarily due to the change in DELTA. The change in the co-ordination of nearest neighbours upon crystallisation was investigated. The topological co-ordination was found to be very similar in both phases. The change in the optical properties is thought to be due to the change in chemical order of the nearest neighbours. This thesis reports on the work carried out by the on the crystallisation kinetics and optical properties of thin amorphous Ge sub 2 Sb sub 2 Te sub 5 films. This study is prompted by the application of these films in optical phase change recording media. The work is partly theoretical and partly experimental in nature. Starting from the general nucleation and growth theory, it was shown that the Johnson-MehI-Avrami-Kolmogorov (JMAK) equation...

  1. High-field magnetization studies of NdNi{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Kim-Ngan, N.-T.H. [Center for Solid State Phys., Krakow (Poland)]|[Pedagogical Univ., Krakow (Poland). Inst. of Physics and Informatics; Radwanski, R.J. [Center for Solid State Phys., Krakow (Poland)]|[Pedagogical Univ., Krakow (Poland). Inst. of Physics and Informatics; Kayzel, F.E. [Amsterdam Univ. (Netherlands). Van der Waals-Zeeman Inst.; Franse, J.J.M. [Amsterdam Univ. (Netherlands). Van der Waals-Zeeman Inst.

    1996-05-01

    Magnetization studies on single-crystalline NdNi{sub 5} in external fields up to 35 T are reported. NdNi{sub 5} is a ferromagnet with a T{sub C} of 7.2 K and the easy magnetic direction is along the a direction. The spontaneous magnetic moment is 2.1{mu}{sub B}/f.u. Along the c-axis, the magnetization amounts to 1.65{mu}{sub B}/f.u. at 35 T. The magnetization process is analyzed within the crystalline electric field approach in combination with exchange interactions, taking into account the contribution of the Ni sublattice. The studies confirm that the charge-formed ground state of the f{sup 3} (Nd{sup 3+}) subsystem is the state {Gamma}{sub 8} with a dominant vertical stroke {+-}5/2 right angle contribution. The full magnetization curves, up to 300 T, have been calculated. The magnetization curve along the c-axis proceeds to saturation with a metamagnetic-like transition at 150 T. (orig.).

  2. Dynamic SIMS utilizing SF{sub 5}{sup +} polyatomic primary ion beams for drug delivery applications

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, Christine M.; Roberson, Sonya; Gillen, Greg

    2004-06-15

    The behavior of various biodegradable polymer films (e.g. polylactic acid, polyglycolic acid and polycaprolactone) as well as some model drugs (theophylline and 4-acetamidophenol) under dynamic SF{sub 5}{sup +} primary ion bombardment is explored. A series of polylactic acid films containing varying concentrations of 4-acetamidophenol are also analyzed under similar conditions. The resultant molecular depth profiles obtained from these polymer films doped with drug show very little degradation in molecular signal as a function of SF{sub 5}{sup +} primary ion dose, and it was found that the molecular ion signals of both polymer and drug remained constant for ion doses up to {approx}5x10{sup 15} ions/cm{sup 2}. In addition, the polymer film/Si interface was well defined which may imply that sputter-induced topography formation was not a significant limitation. These results suggest that the structure of the biodegradable polymers studied here which all have the common main chain structural unit, R-CO-O-R, allows for a greater ability to depth profile due to ease of bond cleavage. Most importantly, however, these results indicate that in these particular polymer systems, the distribution of the drug as a function of depth can be monitored.

  3. Synthesis and photoluminescence property of La doped Pb{sub 5}(VO{sub 4}){sub 3}OH rod bunches

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jing; Zhuo, Fengping; Fu, Ya; Wang, Yue; Yuan, Jinhai, E-mail: materialscqust@126.com; Feng, Jian

    2017-05-10

    The pure Pb{sub 5}(VO{sub 4}){sub 3}OH and La doped Pb{sub 5}(VO{sub 4}){sub 3}OH rod bunches have been synthesized by a simple Composite-Hydroxide-Mediated (CHM) method. The characterization of the doped samples with XRD, EDS and XPS indicated that La{sup 3+} ions were incorporated into the Pb{sub 5}(VO{sub 4}){sub 3}OH lattices. The crystallite size of Pb{sub 5}(VO{sub 4}){sub 3}OH:La{sup 3+} rod bunches was smaller than that of pure Pb{sub 5}(VO{sub 4}){sub 3}OH rod bunches. The possible formation mechanism of rod bunches has been discussed. The photoluminescence property of the Pb{sub 5}(VO{sub 4}){sub 3}OH:La{sup 3+} crystals was investigated at room temperature. The crystals exhibited a strong blue luminescence under UV light (353 nm) excitation at room-temperature. The mechanism of excellent luminescence of Pb{sub 5}(VO{sub 4}){sub 3}OH:La{sup 3+} has been deeply discussed. - Highlights: • Pb{sub 5}(VO{sub 4}){sub 3}OH:La{sup 3+} rod bunches have been synthesized by the CHM method. • The possible formation mechanism of rod bunches has been discussed. • The La{sup 3+} doping in the Pb{sub 5}(VO{sub 4}){sub 3}OH rod bunches can improve the blue luminescence property at room temperature remarkably.

  4. Hybrid fs/ps CARS for Sooting and Particle-laden Flames [PowerPoint

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmeister, Kathryn N. Gabet; Guildenbecher, Daniel Robert; Kearney, Sean P.

    2016-01-01

    We report the application of ultrafast rotational coherent anti-Stokes Raman scattering (CARS) for temperature and relative oxygen concentration measurements in the plume emanating from a burning aluminized ammonium perchlorate propellant strand. Combustion of these metal-based propellants is a particularly hostile environment for laserbased diagnostics, with intense background luminosity, scattering and beam obstruction from hot metal particles that can be as large as several hundred microns in diameter. CARS spectra that were previously obtained using nanosecond pulsed lasers in an aluminumparticle- seeded flame are examined and are determined to be severely impacted by nonresonant background, presumably as a result of the plasma formed by particulateenhanced laser-induced breakdown. Introduction of fs/ps laser pulses enables CARS detection at reduced pulse energies, decreasing the likelihood of breakdown, while simultaneously providing time-gated elimination of any nonresonant background interference. Temperature probability densities and temperature/oxygen correlations were constructed from ensembles of several thousand single-laser-shot measurements from the fs/ps rotational CARS measurement volume positioned within 3 mm or less of the burning propellant surface. Preliminary results in canonical flames are presented using a hybrid fs/ps vibrational CARS system to demonstrate our progress towards acquiring vibrational CARS measurements for more accurate temperatures in the very high temperature propellant burns.

  5. Hybrid fs/ps CARS for Sooting and Particle-laden Flames

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmeister, Kathryn N. Gabet; Guildenbecher, Daniel Robert; Kearney, Sean P.

    2015-12-01

    We report the application of ultrafast rotational coherent anti-Stokes Raman scattering (CARS) for temperature and relative oxygen concentration measurements in the plume emanating from a burning aluminized ammonium perchlorate propellant strand. Combustion of these metal-based propellants is a particularly hostile environment for laserbased diagnostics, with intense background luminosity, scattering and beam obstruction from hot metal particles that can be as large as several hundred microns in diameter. CARS spectra that were previously obtained using nanosecond pulsed lasers in an aluminumparticle- seeded flame are examined and are determined to be severely impacted by nonresonant background, presumably as a result of the plasma formed by particulateenhanced laser-induced breakdown. Introduction of fs/ps laser pulses enables CARS detection at reduced pulse energies, decreasing the likelihood of breakdown, while simultaneously providing time-gated elimination of any nonresonant background interference. Temperature probability densities and temperature/oxygen correlations were constructed from ensembles of several thousand single-laser-shot measurements from the fs/ps rotational CARS measurement volume positioned within 3 mm or less of the burning propellant surface. Preliminary results in canonical flames are presented using a hybrid fs/ps vibrational CARS system to demonstrate our progress towards acquiring vibrational CARS measurements for more accurate temperatures in the very high temperature propellant burns.

  6. Reactivity of ionic oxides through water molecules adsorption process; MgO-V sub 2 O sub 5 behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Goni-Elizalde, S. (Consejo Superior de Investigaciones Cientificas, Madrid (Spain). Instituto de Ciencias de la Construccion Eduardo Torroja); Garcia-Clavel, M.E. (Consejo Superior de Investigaciones Cientificas, Madrid (Spain). Instituto de Edafologia)

    1991-03-01

    Crystalline V{sub 2}O{sub 5} reactivity is strongly dependent on both particle size and relative humidity surrounding the sample. To study the increase of reactivity of crystalline V{sub 2}O{sub 5} (grain size<0.05 mm), a mixture of MgO-V{sub 2}O{sub 5} (1:1) has been kept in a watervapour saturated atmosphere for different periods of time. X-ray diffraction is employed to follow the structural evolution of the mixture, the adsorption process of water molecules has been studied by infrared spectroscopy as well as by thermogravimetry. (author). 11 refs.; 5 figs.; 1 tab.

  7. Negative thermal expansion behavior in single crystal and ceramic of Nb{sub 2}O{sub 5}-based compositions.

    Energy Technology Data Exchange (ETDEWEB)

    Choosuwan, H.; Guo, R.; Bhalla, A. S.; Balachandran, U.; Energy Technology; Pennsylvania State Univ.

    2002-04-15

    The thermal expansion coefficients of a single crystal and ceramic of Nb{sub 2}O{sub 5} are measured in the temperature range of -200-500 C by the dilatometer technique. Both single crystals and ceramics of Nb{sub 2}O{sub 5} and Nb{sub 2}O{sub 5}(1-x):xTiO{sub 2} show negative thermal expansion in this temperature range. Some contribution to the result could be due to the presence of the Magneli phases. The main phase transition temperature, which also matches with the dielectric anomaly, occurs at {approx}150 C.

  8. Characterization of Cu{sub 6}Sn{sub 5} intermetallic powders produced by water atomization and powder heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Tongsri, Ruangdaj, E-mail: ruangdt@mtec.or.th [Powder Metallurgy Research and Development Unit (PM-RDU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand); Yotkaew, Thanyaporn, E-mail: thanyy@mtec.or.th [Powder Metallurgy Research and Development Unit (PM-RDU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand); Krataitong, Rungtip, E-mail: rungtipk@mtec.or.th [Powder Metallurgy Research and Development Unit (PM-RDU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand); Wila, Pongsak, E-mail: pongsakw@mtec.or.th [Powder Metallurgy Research and Development Unit (PM-RDU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand); Sir-on, Autcharaporn, E-mail: autchars@mtec.or.th [Materials Characterization Research Unit (MCRU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand); Muthitamongkol, Pennapa, E-mail: pennapm@mtec.or.th [Materials Characterization Research Unit (MCRU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand); Tosangthum, Nattaya, E-mail: nattayt@mtec.or.th [Powder Metallurgy Research and Development Unit (PM-RDU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand)

    2013-12-15

    Since the Cu{sub 6}Sn{sub 5} intermetallic shows its importance in industrial applications, the Cu{sub 6}Sn{sub 5} intermetallic-containing powders, produced by a powder processing route with a high production rate, were characterized. The route consisted of water atomization of an alloy melt (Cu–61 wt.% Sn) and subsequent heat treatment of the water-atomized powders. Characterization of the water-atomized powders and their heated forms was conducted by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Fine water-atomized powder microstructures consisted of primary hexagonal η-Cu{sub 6.25}Sn{sub 5} dendrites coexisting with interdendritic η-Cu{sub 6.25}Sn{sub 5} + β-Sn eutectic. Solidification of fine melt droplets was governed by surface nucleation and growth of the primary hexagonal η-Cu{sub 6.25}Sn{sub 5} dendrites followed by η-Cu{sub 6.25}Sn{sub 5} + β-Sn eutectic solidification of the remnant liquid. In coarse melt droplets, nucleation and growth of primary ε-Cu{sub 3}Sn dendrites were followed by peritectic reaction (ε-Cu{sub 3}Sn + liquid → η-Cu{sub 6.25}Sn{sub 5}) or direct crystallization of η-Cu{sub 6.25}Sn{sub 5} phase from the undercooled melt. Finally, the η-Cu{sub 6.25}Sn{sub 5} + β-Sn eutectic solidification of the remnant liquid occurred. Heating of the water-atomized powders at different temperatures resulted in microstructural homogenization. The water-atomized powders with mixed phases were transformed to powders with single monoclinic ή-Cu{sub 6}Sn{sub 5} phase. - Highlights: • The Cu{sub 6}Sn{sub 5} intermetallic powder production route was proposed. • Single phase Cu{sub 6}Sn{sub 5} powders could be by water atomization and heating. • Water-atomized Cu–Sn powders contained mixed Cu–Sn phases. • Solidification and heat treatment of water-atomized Cu–Sn powders are explained.

  9. High-power 100-fs SESAM-modelocked VESCEL (Conference Presentation)

    Science.gov (United States)

    Waldburger, Dominik; Link, Sandro M.; Alfieri, Cesare G. E.; Golling, Matthias; Keller, Ursula

    2017-03-01

    Ultrafast vertical external-cavity surface-emitting lasers (VECSELs) are versatile laser sources and feature high-power operation. To date the best modelocking results have been achieved with a semiconductor saturable absorber mirror (SESAM). Ultrafast optically pumped semiconductor disk lasers (SDLs) are compact, cost-efficient and provide excellent beam quality at gigahertz pulse repetition rates for applications such as for example multi-photon imaging, ultrafast communication and in particular self-referenced gigahertz frequency combs. The highest peak power obtained with an ultrafast VECSEL is 4.35 kW in 400-fs pulses and the shortest pulses until now are 107 fs at 3 mW average output power. Here we present a SESAM-modelocked VECSEL with pulses as short as 96 fs and 100 mW average output power. These are to the best of our knowledge the shortest pulses achieved by a fundamentally modelocked SDL and result in a very high peak power of 0.56 kW at a pulse repetition rate of 1.63 GHz. The short pulse duration was achieved by introducing a small amount of positive group delay dispersion with a single path through an external 2-mm thick ZnSe window plate that compensated the initially negatively chirped 107-fs output pulses. Currently the power is limited by the transition from fundamental modelocking to multi-pulse operation, which reduces the pulse peak power and introduces additional noise. Therefore, we present a study of the multi-pulse behavior of the high-power 100-fs SDL resulting from the complex modelocking mechanism. This study also provides an insight into special issues of pulse characterization that may suggest stable fundamental modelocking even if this is not the case.

  10. Comparing the dynamic and thermodynamic behaviors of Al{sub 86}Ni{sub 9}-La{sub 5}/(La{sub 0.5}Ce{sub 0.5}){sub 5} amorphous alloys

    Energy Technology Data Exchange (ETDEWEB)

    Li, G.H. [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Wang, W.M. [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)], E-mail: weiminw@sdu.edu.cn; Bian, X.F.; Zhang, J.T.; Li, R.; Wang, L. [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)

    2009-06-10

    The dynamic viscosities and thermodynamic dilatometric behaviors of Al{sub 86}Ni{sub 9}La{sub 5} and Al{sub 86}Ni{sub 9}(La{sub 0.5}Ce{sub 0.5}){sub 5} amorphous alloys were investigated using viscometer, differential scanning calorimetry (DSC) and conventional dilatometer. Comparing with Al{sub 86}Ni{sub 9}La{sub 5} alloy, Al{sub 86}Ni{sub 9}(La{sub 0.5}Ce{sub 0.5}){sub 5} alloy exhibits a larger viscosity and a larger average thermal expansion coefficient in the linear expansion zone ({alpha}{sub exp}). The viscosity and thermal expansion data suggest that the partial substitution La by Ce decreases the quantity of free volume in Al-Ni-La system by improving the continuous degree of atomic size, which leads to the improvement of glass forming ability.

  11. Proton glass behaviour in a solid solution of gamma-irradiated deuterated betaine phosphate sub 0 sub . sub 1 sub 5 betaine phosphite sub 0 sub . sub 8 sub 5

    CERN Document Server

    Banys, J; Klimm, C; Voelkel, G; Kloepperpieper, A

    1997-01-01

    Measurements of the dielectric permittivity are reported for a deuterated solid solution of gamma-irradiated antiferroelectric (betainephosphate) sub 0 sub . sub 1 sub 5 ferroelectric (betainephosphite) sub 0 sub . sub 8 sub 5 at frequencies 20 H sub Z sub 5 DBPI sub 0 sub . sub 8 sub 5 revealed the characteristics of a transition into a dipolar glass state. The activation energy was found to be E sub b = 311.6 K (0.027 eV). The Kutnjak model showed a non-typical glass behaviour with an estimated glass temperature of 55.4 K. (author). Letter-to-the-editor

  12. Mechanism for the exchange processes observed in the compounds [M({eta}-C{sub 5}H{sub 5}){sub 2}({eta}-RCH=CH{sub 2})H] (M = Nb, Ta)

    Energy Technology Data Exchange (ETDEWEB)

    Green, M.L.H.; Wong, Luet-Lok [Inorganic Chemistry Lab., Oxford (United Kingdom); Sella, A. [Univ. College, London (United Kingdom)

    1992-07-01

    The fluxional processes in the compounds exo-[M({eta}-C{sub 5}H{sub 5}){sub 2}({eta}CH{sub 3}CH=CH{sub 2})H] (M = Nb, Ta) have been investigated by magnetization and spin-saturation transfer and two-dimensional exchange NMR techniques. Rate constants for three separate processes have been determined. A mechanism involving agostic {eta}{sup 2}-alkyl ligands is proposed. 62 refs., 11 figs., 2 tabs.

  13. Influence of structural disorder on the optical and transport properties of Co sub 0 sub . sub 5 sub 0 Ti sub 0 sub . sub 5 sub 0 alloy films

    CERN Document Server

    Kim, K W; Rhee, J Y; Kudryavtsev, Y V; Ri, H C

    2000-01-01

    Co sub 0 sub . sub 5 sub 0 Ti sub 0 sub . sub 5 sub 0 alloy films with a total thickness of about 100 nm were prepared by flash evaporation of the crushed alloy powders onto heated (730 K for the ordered state) and LN sub 2 -cooled (150 K for the disordered state) substrates. Structural analysis of the films was performed by suing transmission electron microscopy. The optical conductivity (OC) of the samples was measured at room temperature in a spectral range of 265 -2500 nm (4.7 - 0.5 eV). The resistivity measurements were carried out by using the four-probe technique in a temperature range of 4.2 - 300 K. The experimental OC spectra for the Co sub 0 sub . sub 5 sub 0 Ti sub 0 sub . sub 5 sub 0 alloys show the most significant change in the infrared region upon the order-disorder transformation. The structural disorder in the Co sub 0 sub . sub 5 sub 0 Ti sub 0 sub . sub 5 sub 0 alloy film leads to a change in the sign of the temperature coefficient of the resistivity from positive to negative. The observed...

  14. 1 μJ, sub-500 fs chirped pulse amplification in a Tm-doped fiber system.

    Science.gov (United States)

    Sims, R Andrew; Kadwani, Pankaj; Shah, Alex Sincore Lawrence; Richardson, Martin

    2013-01-15

    We demonstrate a Tm-doped fiber laser system producing ~300 fs pulses with 1 μJ energy, corresponding to peak powers greater than 3 MW. Pulses of 150 fs with 30 nm spectral bandwidth and 3 nJ pulse energy are generated in a Raman-soliton self-frequency shift amplifier, then stretched to ~160 ps using a chirped Bragg grating. The 60 MHz oscillator repetition rate is reduced to 100 kHz using an electro-optic modulator. After a single-mode fiber preamplifier and a large-mode-area fiber power amplifier, pulses were compressed using a folded Treacy grating setup to below 500 fs with up to 1 μJ pulse energy. To the best of our knowledge, this is the highest energy yet demonstrated as well as the first demonstration of peak powers exceeding 1 MW from a Tm:fiber laser system.

  15. High capacity, microporous Cu{sub 6}Sn{sub 5}-Sn anodes for Li-Ion batteries.

    Energy Technology Data Exchange (ETDEWEB)

    Trahey, L.; Vaughey, J. T.; Kung, H. H.; Thackeray, M. M. (Chemical Sciences and Engineering Division); ( PSC-USR); (Northwestern Univ.)

    2009-03-16

    Three-dimensional, microporous Cu{sub 6}Sn{sub 5}-Sn architectures were created by electrodeposition of copper and tin onto sintered copper foam substrates and evaluated as anodes for lithium-ion batteries. The electrodes were characterized before and after cycling by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectrometry. Before cycling, the electrochemically deposited films consisted of a combination of crystalline Cu{sub 6}Sn{sub 5} and Sn, whereas after cycling, the films appeared amorphous to X-rays. When evaluated in coin cells against metallic lithium, the composite Cu{sub 6}Sn{sub 5}-Sn electrodes delivered a reversible capacity of 670 mAh/g, which is significantly greater than the capacity achieved previously from powdered (ballmilled) and thin-film (sputtered) Cu{sub 6}Sn{sub 5} electrodes, typically 200-350 mAh/g.

  16. Magnetic characterization of Pr{sub 2}BaCuO{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Saez Puche, R [Departamento de Quimica Inorganica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, 28040 Madrid (Spain); Climent-Pascual, E [Departamento de Quimica Inorganica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, 28040 Madrid (Spain); Paz, J Romero de [Departamento de Quimica Inorganica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, 28040 Madrid (Spain); Fernandez-Diaz, M T [Institut Laue-Langevin, BP 156X, F-38042 Grenoble Cedex (France); Cascales, C [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28094-Madrid (Spain)

    2008-01-30

    The magnetic behaviour of Pr{sub 2}BaCuO{sub 5} oxide has been studied by means of magnetic susceptibility, magnetization, specific heat and neutron powder diffraction at low temperatures. This oxide behaves as an antiferromagnetic with a Neel temperature of 13.7 K and the magnetic structure can be described on the basis of a wavevector k = [0,0,0]. The Cu{sup 2+} magnetic moments are aligned along the c-axis of the crystal structure, while the Pr{sup 3+} magnetic moments lie in the ab-plane with a small component along the c-axis. The experimental values of the ordered moments at 2 K are 0.9(3) and 0.8(3) {mu}{sub B} for copper and praseodymium ions, respectively. The obtained set of crystal field parameters reproduces the paramagnetic susceptibility measurements and justifies the low experimental ordered moment of the Pr{sup 3+} ion.

  17. High-field magnetization and specific heat of TmNi{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Kayzel, F.E. [Amsterdam Univ. (Netherlands). Van der Waals-Zeeman Inst.; Franse, J.J.M. [Amsterdam Univ. (Netherlands). Van der Waals-Zeeman Inst.; Colpa, J.H.P. [Amsterdam Univ. (Netherlands). Van der Waals-Zeeman Inst.; Kim-Ngan, N.-H. [Centre for Solid State Physics, Krakow (Poland); Tai, L.T. [Amsterdam Univ. (Netherlands). Van der Waals-Zeeman Inst.; Radwanski, R.J. [Centre for Solid State Physics, Krakow (Poland); Gignoux, D. [Centre National de la Recherche Scientifique (CNRS), 38 -Grenoble (France). Lab. Louis Neel

    1996-05-01

    High-field magnetization on two single-crystalline samples from different batches of TmNi{sub 5} has been measured along the crystallographic a, b and c directions up to 38 T at 1.5 K. A small high-field susceptibility {chi}{sub HF}=6.3.10{sup -3} {mu}{sub B}/T f.u. was observed along the easy c-axis. The magnetization measured alon g both a- and b-axis shows hysteresis and a magnetic transition between 5 and 15 T. Specific heat has been measured from 1.5 to 160 K. A {lambda}-type peak found at about 3.7 K originates from the magnetic system. (orig.).

  18. Thermodynamic signatures for the existence of Dirac electrons in ZrTe<sub>5

    Energy Technology Data Exchange (ETDEWEB)

    Nair, Nityan L. [Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Dumitrescu, Philipp T. [Univ. of Texas, Austin, TX (United States). Dept. of Physics; Channa, Sanyum [Univ. of California, Berkeley, CA (United States). Dept. of Physics; Griffin, Sinead M. [Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Foundry; Neaton, Jeffrey B. [Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Foundry; Univ. of California, Berkeley, CA (United States). Kavli Energy NanoScience Inst.; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Potter, Andrew C. [Univ. of Texas, Austin, TX (United States). Dept. of Physics; Analytis, James G. [Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division

    2017-09-12

    We combine transport, magnetization, and torque magnetometry measurements to investigate the electronic structure of ZrTe<sub>5 and its evolution with temperature. At fields beyond the quantum limit, we observe a magnetization reversal from paramagnetic to diamagnetic response, which is characteristic of a Dirac semi-metal. We also observe a strong non-linearity in the magnetization that suggests the presence of additional low-lying carriers from other low-energy bands. Finally, we observe a striking sensitivity of the magnetic reversal to temperature that is not readily explained by simple band-structure models, but may be connected to a temperature dependent Lifshitz transition proposed to exist in this material.

  19. A 1D coordination polymer of UF{sub 5} with HCN as a ligand

    Energy Technology Data Exchange (ETDEWEB)

    Scheibe, Benjamin; Rudel, Stefan S.; Buchner, Magnus R.; Kraus, Florian [Fachbereich Chemie, Philipps-Universitaet Marburg (Germany); Karttunen, Antti J. [Department of Chemistry, Aalto University (Finland)

    2017-01-05

    β-Uranium(V) fluoride was reacted with liquid anhydrous hydrogen cyanide to obtain a 1D coordination polymer with the composition {sup 1}{sub ∞}[UF{sub 5}(HCN){sub 2}], {sup 1}{sub ∞}[UF{sub 4/1}F{sub 2/2}-(HCN){sub 2/1}], revealed by single-crystal X-ray structure determination. The reaction system was furthermore studied by means of vibrational and NMR spectroscopy, as well as by quantum chemical calculations. The compound presents the first described polymeric HCN Lewis adduct and the first HCN adduct of a uranium fluoride. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Resurgence of the dressing phase for AdS{sub 5}×S{sup 5}

    Energy Technology Data Exchange (ETDEWEB)

    Arutyunov, Gleb [Institut für Theoretische Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Zentrum für Mathematische Physik, Universität Hamburg, Bundesstrasse 55, 20146 Hamburg (Germany); Dorigoni, Daniele [Centre for Particle Theory & Department of Mathematical Sciences, Durham University, Lower Mountjoy Stockton Road, Durham DH1 3LE (United Kingdom); Savin, Sergei [Institut für Theoretische Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Zentrum für Mathematische Physik, Universität Hamburg, Bundesstrasse 55, 20146 Hamburg (Germany)

    2017-01-13

    We discuss the resummation of the strong coupling asymptotic expansion of the dressing phase of the AdS{sub 5}×S{sup 5} superstring. The dressing phase proposed by Beisert, Eden and Staudacher can be recovered from a modified Borel-Ecalle resummation of this asymptotic expansion only by completing it with new, non-perturbative and exponentially suppressed terms that can be organized into different sectors labelled by an instanton-like number. We compute the contribution to the dressing phase coming from the sum over all the instanton sectors and show that it satisfies the homogeneous crossing symmetry equation. We comment on the semiclassical origin of the non-perturbative terms from the world-sheet theory point of view even though their precise explanation remains still quite mysterious.

  1. Thermal and galvanomagnetic properties of monocrystals CuInGa{sub 2}Te{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Abilov, Ch. I., E-mail: cabilov@yahoo.com; Hasanova, M. Sh., E-mail: mhsh28@mail.ru; Huseynova, N. T. [Azerbaijan Technical University, Baku (Azerbaijan); Zeynalov, S. A. [Azerbaijan Institute of Teachers, Baku (Azerbaijan)

    2016-03-25

    By the methods of the physic-chemical analysis, determination of density and by measurement of micro hardness the character of chemical interaction in the In{sub 2}Te{sub 3}-Cu{sub 2}Ga{sub 4}Te{sub 7} system has been investigated and its faze diagram has been plotted. It is established that the system is quasibinary, of eutectic type. In the system the chemical combination of CuGa{sub 2}InTe{sub 5} composition melting congruently at 855°C is generated. There have been revealed solid solutions boundary of which based on In{sub 2}Te{sub 3} reach 5mol% at room temperatures. Temperature dependences of electric conductivity, the coefficient of thermo-emf, general heat conductivity, the Hall mobility of charge carriers.The mechanisms of electron-phonon diffusion in crystals of its compound have been revealed.

  2. Ferroelectric properties of neodymium-doped Sr{sub 2}Bi{sub 4}Ti{sub 5}O{sub 18} thin film prepared by solgel route

    Energy Technology Data Exchange (ETDEWEB)

    Cui, L. [Suqian College, fundamental department, Suqian 223800 (China); Hu, Y.J. [Hubei University of Automotive Industries Technology, Shiyan 442011 (China)], E-mail: eric8222@126.com

    2009-01-15

    Sr{sub 2}Bi{sub 4}Ti{sub 5}O{sub 18} (SBTi) and Nd-modified SBTi (SBNT) thin films were deposited on Pt/Ti/SiO{sub 2}/Si (1 0 0) substrates using a sol-gel method. Structure, morphology and electric properties were investigated systematically. These films were randomly oriented and composed of rod-like grains. The remanent polarization (2P{sub r}) and coercive field (E{sub c}) of SBNT films were 30 {mu}C/cm{sup 2} and 55 kV/cm, respectively. This value of 2P{sub r} was much higher than the reported value of SBTi prepared by pulsed-laser deposition. More importantly, the SBNT films showed high fatigue resistance against continuous switching up to 3x10{sup 9} cycles and excellent charge-retaining ability up to 3x10{sup 4} s.

  3. Transfer hydrogenation of olefin from alcohol using a hydrogen-absorbing alloy (CaNi{sub 5}) catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Imamura, H.; Tanaka, T.; Sakata, Y.; Tsuchiya, S. [Yamaguchi Univ., Ube (Japan). Faculty of Engineering

    1999-12-20

    Gas-phase reactions between 2-butene and 2-propanol on a hydrogen-absorbing alloy CaNi{sub 5} have been studied in the temperature range of 393 to 473 K. CaNi{sub 5} showed interesting characteristics as an active catalyst for the transfer hydrogenation of butene from propanol as a hydrogen donor. 2-Propanol was effectively dehydrogenated to yield acetone, in which the dissociated hydrogen was completely absorbed by CaNi{sub 5} to form the metal hydride. When the alloy was hydrided to some extent, butene was effectively hydrogenated by the absorbed hydrogen in the metal hydride to produce butane. The overall reaction was expressed as catalytic transfer hydrogenation through the formation of metal hydride intermediates (CaNi{sub 5}H{sub n}). Catalytic transfer hydrogenation on CaNi{sub 5} occurred at 423 K via hydriding of CaNi{sub 5} by 2-propanol dehydrogenation with subsequent dehydriding for the hydrogenation of 2-butene, rather than the direct reaction between 2-butene and 2-propanol on the alloy. (orig.)

  4. Hydrothermal synthesis of HoMn{sub 2}O{sub 5} nanorods and their size-dependent magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Yichao; Wu, Songping, E-mail: chwsp@scut.edu.cn; Xu, Rui

    2017-03-01

    The HoMn{sub 2}O{sub 5} nanorods were synthesized by a surfactant-assisted hydrothermal process. The length of nanorods is readily controllable with basically constant diameter. HoMn{sub 2}O{sub 5} nanorods show recognizable divagation at T{sub N}(Ho) of 13 K between FC and ZFC curve due to the contribution of the magnetic ordering of holmium. Size-dependent magnetic properties (i.e. a critical length for magnetization) of HoMn{sub 2}O{sub 5} nanorods can be ascribed to the competition between surface strain and uncompensated spin at the surface. - Highlights: • HoMn{sub 2}O{sub 5} nanorods were synthesized by a surfactant-assisted hydrothermal route. • HoMn{sub 2}O{sub 5} nanorods show recognizable divagation at T{sub N}(Ho) of 13 K between FC and ZFC. • Size-dependent magnetic properties of HoMn{sub 2}O{sub 5} nanorods can be observed.

  5. Optimizing white light luminescence in Dy{sup 3+}-doped Lu{sub 3}Ga{sub 5}O{sub 12} nano-garnets

    Energy Technology Data Exchange (ETDEWEB)

    Haritha, P.; Linganna, K.; Venkatramu, V., E-mail: vvramuphd@gmail.com [Department of Physics, Yogi Vemana University, Kadapa - 516 003 (India); Martín, I. R.; Monteseguro, V.; Rodríguez-Mendoza, U. R. [Department of Physics, and MALTA Consolider Team, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain); Instituto Universitario de Materiales y Nanotecnología, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain); Babu, P. [Department of Physics, Government Degree College, Satyavedu - 517 588 (India); León-Luis, S. F. [Department of Physics, and MALTA Consolider Team, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain); Jayasankar, C. K. [Department of Physics, Sri Venkateswara University, Tirupati - 517 502 (India); Lavín, V. [Department of Physics, and MALTA Consolider Team, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain); Instituto Universitario de Estudios Avanzados en Atómica, Molecular y Fotónica, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain)

    2014-11-07

    Trivalent dysprosium-doped Lu{sub 3}Ga{sub 5}O{sub 12} nano-garnets have been prepared by sol-gel method and characterized by X-ray powder diffraction, high-resolution transmission electron microscopy, dynamic light scattering, and laser excited spectroscopy. Under a cw 457 nm laser excitation, the white luminescence properties of Lu{sub 3}Ga{sub 5}O{sub 12} nano-garnets have been studied as a function of the optically active Dy{sup 3+} ion concentration and at low temperature. Decay curves for the {sup 4}F{sub 9/2} level of Dy{sup 3+} ion exhibit non-exponential nature for all the Dy{sup 3+} concentrations, which have been well-fitted to a generalized energy transfer model for a quadrupole-quadrupole interaction between Dy{sup 3+} ions without diffusion. From these data, a simple rate-equations model can be applied to predict that intense white luminescence could be obtained from 1.8 mol% Dy{sup 3+} ions-doped nano-garnets, which is in good agreement with experimental results. Chromaticity color coordinates and correlated color temperatures have been determined as a function of temperature and are found to be within the white light region for all Dy{sup 3+} concentrations. These results indicate that 2.0 mol% Dy{sup 3+} ions doped nano-garnet could be useful for white light emitting device applications.

  6. Nanosecond in situ transmission electron microscope studies of the reversible Ge{sub 2}Sb{sub 2}Te{sub 5} crystalline <==> amorphous phase transformation

    Energy Technology Data Exchange (ETDEWEB)

    Santala, M. K.; Reed, B. W.; LaGrange, T.; Campbell, G. H.; Browning, N. D. [Condensed Matter and Materials Division, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Topuria, T. [IBM Research Division, Almaden Research Center, San Jose, California 95120 (United States); Raoux, S. [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Meister, S. [Intel Corporation, Hillsboro, Oregon 97124 (United States); Cui, Y. [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2012-01-15

    Chalcogenide-based phase-change materials have wide use in optical recording media and are growing in importance for use in non-volatile electronic memory. For both applications, rapid switching between the amorphous and crystalline phases is necessary, and understanding the changes during rapidly driven phase transitions is of scientific and technological significance. Laser-induced crystallization and amorphization occur rapidly and changes in atomic structure, microstructure, and temperature are difficult to observe experimentally and determine computationally. We have used nanosecond-scale time-resolved diffraction with intense electron pulses to study Ge{sub 2}Sb{sub 2}Te{sub 5} during laser crystallization. Using a unique and unconventional specimen geometry, cycling between the amorphous and crystalline phases was achieved, enabling in situ transmission electron microscope (TEM) study of both microstructural and crystallographic changes caused by repeated switching. Finite element analysis was used to simulate interactions of the laser with the nano-structured specimens and to model the rapidly changing specimen temperature. Such time-resolved experimental methods combined with simulation of experimentally inaccessible physical characteristics will be fundamental to advancing the understanding of rapidly driven phase transformations.

  7. Femtosecond Laser Effects on Osseous Tissues

    Science.gov (United States)

    Girard, B.; Yu, D.; Armstrong, M. R.; Wilson, B. C.; Clokie, C. M. L.; Miller, R. J. D.

    We have investigated the effects of femtosecond (fs) laser irradiation on bone samples in in vitro and on ex vivo living bone samples. Ablation threshold, material removed per pulse and plasma shielding were examined using in vitro samples. Ablation threshold was found to be 0.9J/cm2 at 775nm and 0.3J/cm2 at 367nm using 200fs pulses. Material removal was found to vary non-linearly with pulse energy. Using in vivo samples we have demonstrated intact enzymatic activity on the surface of cells immediately adjacent to cells removed by fs laser irradiation suggesting no thermal damage.

  8. [Understanding the advantages and disadvantages of femtosecond laser comprehensive applications in ophthalmology].

    Science.gov (United States)

    Xie, Li-xin; Gao, Hua

    2013-04-01

    The femtosecond (FS) laser is a novel laser technology, and is approved clinical application by FDA in 2000. FS laser initially mainly used in corneal refractive surgery to replace the mechanical microkeratome. Since the accuracy and controllability of the FS laser is very high, it shows superiority in the field of corneal refractive surgery. And with the development of the relative hard and software, FS laser is began to used in other fields of ophthalmology, such as corneal transplants, cataract surgery, as well as assisted diagnosis et al., although still have some limitations, the preliminary clinical results have been shown a very good prospects in the ophthalmology fields. Therefore, we reviewed the alternative applications, challenges and limitations, research direction in the future of FS laser, so that provide a reference and revelations for the peers.

  9. Femtosecond laser materials processing

    Energy Technology Data Exchange (ETDEWEB)

    Stuart, B. C., LLNL

    1998-06-02

    Femtosecond lasers enable materials processing of most any material with extremely high precision and negligible shock or thermal loading to the surrounding area Applications ranging from drilling teeth to cutting explosives to making high-aspect ratio cuts in metals with no heat-affected zone are made possible by this technology For material removal at reasonable rates, we developed a fully computer-controlled 15-Watt average power, 100-fs laser machining system.

  10. Laser modification of silica, simulating pulse shape and length

    Energy Technology Data Exchange (ETDEWEB)

    Corrales, L. Rene [Departments of Materials Science and Engineering, and Chemistry, University of Arizona, Tucson, Arizona 85721 (United States)], E-mail: lrcorral@email.arizona.edu; Moore, Emily [Departments of Materials Science and Engineering, and Chemistry, University of Arizona, Tucson, Arizona 85721 (United States)

    2009-09-15

    Computer simulations of instantaneous thermal heating due to a laser pulse is modeled as a pulse occurring over 1 or 100 fs, during which time the atoms within a cylinder are given excess kinetic energy to mimic the effect of adding energy locally to a system by a laser. The response of the material under conditions in which a similar amount of energy is dumped within 1 fs versus over a 100 fs pulse with two distinct shapes, square and Gaussian-like, is explored. Key physics disclosed is that with a pulse width of 100 fs, as the energy is being added it begins to dissipate away from region where it is added. With a 1 fs (instantaneous) pulse there is greater initial ballistic behavior than when it is dumped over a 100 fs period. In the latter, there are localized hot spots displaying ballistic behavior.

  11. The Three Fs of Classroom Management

    Science.gov (United States)

    Daniels, Mark L.

    2009-01-01

    This article describes a cohesive theory of classroom management, developed by the author. This "three Fs" theory, predicated upon extant empiricism and scholarship vis-a-vis classroom management, was devised and implemented over several semesters within a field-based course at the University of Texas at Austin for preservice mathematics majors…

  12. Polarized luminescence of Y sub 3 Al sub 5 O sub 1 sub 2 -Tb and Y sub 3 Al sub 5 O sub 1 sub 2 -Ho garnets controllable by magnetic field

    CERN Document Server

    Valiev, U V; Sokolov, B Y

    2002-01-01

    One studied spectra of circularly polarized luminescence of Y sub 3 Al sub 5 O sub 1 sub 2 -Tb and Y sub 3 Al sub 5 O sub 1 sub 2 -Ho garnets within sup 5 D sub 4 -> sup 7 F sub 5 -transition wave length range in Tb sup 3 sup + and within sup 5 S sub 2 -> sup 5 I sub 8 -transition wave length range in Ho sup 3 sup + ion. One detected substantial difference in intensity of orthogonal circularly polarized garnets. The obtained results enable to conclude that strong effect of magnetic field on intensity of oscillator of 4f -> 4f-transitions is general phenomenon in rare-earth system with energy spectrum quasi-doublet structure. Contribution of mixing in external magnetic field of Tb sup 3 sup + and Ho sup 3 sup + ion electron states may play essential role in magnetooptics of such systems

  13. Development of a high-performance nanostructured V(sub2)O(sub5)/SnO(sub2)catalyst for efficient benzene hydroxylation

    CSIR Research Space (South Africa)

    Makgwane, PR

    2015-02-01

    Full Text Available Nanostructured vanadium-tin oxide (V(sub2)O(sub5)/SnO(sub2)) catalysts with V(sub2)O(sub5) loading in a range of 5–20 wt% have been synthesized. The V(sub2)O(sub5)/SnO(sub2) nanostructures exhibited effective catalytic performance...

  14. Femtosecond laser in refractive and cataract surgeries

    Directory of Open Access Journals (Sweden)

    Han-Han Liu

    2015-04-01

    Full Text Available In the past few years, 9 unique laser platforms have been brought to the market. As femtosecond (FS laser-assisted ophthalmic surgery potentially improves patient safety and visual outcomes, this new technology indeed provides ophthalmologists a reliable new option. But this new technology also poses a range of new clinical and financial challenges for surgeons. We provide an overview of the evolution of FS laser technology for use in refractive and cataract surgeries. This review describes the available laser platforms and mainly focuses on discussing the development of ophthalmic surgery technologies.

  15. Molecular dynamics-based refinement and validation for sub-5 Å cryo-electron microscopy maps

    Science.gov (United States)

    Singharoy, Abhishek; Teo, Ivan; McGreevy, Ryan; Stone, John E; Zhao, Jianhua; Schulten, Klaus

    2016-01-01

    Two structure determination methods, based on the molecular dynamics flexible fitting (MDFF) paradigm, are presented that resolve sub-5 Å cryo-electron microscopy (EM) maps with either single structures or ensembles of such structures. The methods, denoted cascade MDFF and resolution exchange MDFF, sequentially re-refine a search model against a series of maps of progressively higher resolutions, which ends with the original experimental resolution. Application of sequential re-refinement enables MDFF to achieve a radius of convergence of ~25 Å demonstrated with the accurate modeling of β-galactosidase and TRPV1 proteins at 3.2 Å and 3.4 Å resolution, respectively. The MDFF refinements uniquely offer map-model validation and B-factor determination criteria based on the inherent dynamics of the macromolecules studied, captured by means of local root mean square fluctuations. The MDFF tools described are available to researchers through an easy-to-use and cost-effective cloud computing resource on Amazon Web Services. DOI: http://dx.doi.org/10.7554/eLife.16105.001 PMID:27383269

  16. Single gap s-wave superconductivity in Nb{sub 2}PdS{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Shruti [School of Physical Sciences, JNU, New Delhi (India); Goyal, R.; Awana, V.P.S. [CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Patnaik, S., E-mail: spatnaik@mail.jnu.ac.in [School of Physical Sciences, JNU, New Delhi (India)

    2016-05-15

    Highlights: • In this paper, we report on pairing symmetry and superconducting gap in recently discovered superconductor Nb2PdS5. • This is a remarkable superconductor with highest ever reported Hc2/Tc ratio of ∼3. • In some theoretical studies, such effects have been ascribed to multiband effects and possible p-wave superconductivity. • However our penetration depth data is well ascribed to a single gap nodeless S-wave superconductivity. - Abstract: Superconducting order parameter and its symmetry are important parameters towards deciphering the pairing mechanism in newly discovered superconducting systems. We report a study on penetration depth measurement on Nb{sub 2}PdS{sub 5} that has recently been reported with extremely high upper critical field with possible triplet pairing mechanism. Our data show that at low temperatures the change in penetration depth Δλ is best fitted with BCS s-wave model for single gap with zero-temperature value of the superconducting energy gap Δ{sub 0} = 1.05 meV, corresponding to the ratio 2Δ{sub 0}/k{sub B}T{sub c} = 3.9 ± 0.18. The superfluid density in the entire temperature range is well described by single gap with gap ratio 2Δ{sub 0}/k{sub B}T{sub c} = 4.1 ± 0.13 for λ(0) = 225 nm.

  17. Supersymmetric AdS{sub 5} solutions of massive IIA supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Apruzzi, Fabio [Institut für Theoretische Physik, Leibniz Universität Hannover,Appelstraße 2, 30167 Hannover (Germany); Fazzi, Marco [Physique Théorique et Mathématique, Université Libre de Bruxelles,Campus Plaine C.P. 231, B-1050 Bruxelles (Belgium); International Solvay Institutes,Bruxelles (Belgium); Passias, Achilleas; Tomasiello, Alessandro [Dipartimento di Fisica, Università di Milano-Bicocca,Piazza della Scienza 3, I-20126 Milano (Italy); INFN, sezione di Milano-Bicocca,Milano (Italy)

    2015-06-29

    Motivated by a recently found class of AdS{sub 7} solutions, we classify AdS{sub 5} solutions in massive IIA, finding infinitely many new analytical examples. We reduce the general problem to a set of PDEs, determining the local internal metric, which is a fibration over a surface. Under a certain simplifying assumption, we are then able to analytically solve the PDEs and give a complete list of all solutions. Among these, one class is new and regular. These spaces can be related to the AdS{sub 7} solutions via a simple universal map for the metric, dilaton and fluxes. The natural interpretation of this map is that the dual CFT{sub 6} and CFT{sub 4} are related by twisted compactification on a Riemann surface Σ{sub g}. The ratio of their free energy coefficients is proportional to the Euler characteristic of Σ{sub g}. As a byproduct, we also find the analytic expression for the AdS{sub 7} solutions, which were previously known only numerically. We determine the free energy for simple examples: it is a simple cubic function of the flux integers.

  18. High field magnetization and specific heat of ErNi{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Kayzel, F.E.; Franse, J.J.M. [Univ. van Amsterdam (Netherlands). Van der Waals-Zeeman Lab.; Radwanski, R.J. [Centre for Solid State Physics, Krakow (Poland)

    1994-03-01

    High field magnetization studies of single crystalline ErNi{sub 5} in fields up to 38T at 1.5K along the main crystallographic directions have been performed. Along the easy direction, the hexagonal axis, the spontaneous magnetization, M{sub s}, amounts to 8.62{mu}{sub B}/f.u. The high-field susceptibility is very small and equal to 41 {times} 10{sup {minus}4}{mu}{sub B}/Tf.u. There exists a distinct difference between the curves along the a- and b-axis. The a-axis curve monotonously increases with field up to 38T. The b-axis curve coincides with the a-axis curve up to 12T but starts to deviate from it above this field, resulting in a value for the magnetization at 38T which is almost the full moment value. The specific beat of a newly-grown single-crystalline sample has been measured in zero field and in applied fields along the c-axis (B = 0.3, 1, 2, 5T). The zero-field measurements coincide with previously reported results The specific heat shows a rapid decrease of the ferrimagnetic order with applied field. Already in 1T, the sharp lambda-type of peak at the magnetic transition is decreased by two third and becomes a broad bump that coincides with the la measurement above 30K. Higher fields further suppress the transition.

  19. Sub-5 nm, globally aligned graphene nanoribbons on Ge(001)

    Energy Technology Data Exchange (ETDEWEB)

    Kiraly, Brian; Mannix, Andrew J. [Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Building 440, Argonne, Illinois 60439 (United States); Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208 (United States); Jacobberger, Robert M.; Arnold, Michael S. [Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Fisher, Brandon L.; Guisinger, Nathan P., E-mail: nguisinger@anl.gov, E-mail: m-hersam@northwestern.edu [Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Building 440, Argonne, Illinois 60439 (United States); Hersam, Mark C., E-mail: nguisinger@anl.gov, E-mail: m-hersam@northwestern.edu [Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208 (United States); Department of Chemistry, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208 (United States)

    2016-05-23

    Graphene nanoribbons (GNRs) hold great promise for future electronics because of their edge and width dependent electronic bandgaps and exceptional transport properties. While significant progress toward GNR devices has been made, the field has been limited by difficulties achieving narrow widths, global alignment, and atomically pristine GNR edges on technologically relevant substrates. A recent advance has challenged these limits by using Ge(001) substrates to direct the bottom-up growth of GNRs with nearly pristine armchair edges and widths near ∼10 nm via atmospheric pressure chemical vapor deposition. In this work, the growth of GNRs on Ge(001) is extended to ultra-high vacuum conditions, resulting in the realization of GNRs with widths narrower than 5 nm. Armchair graphene nanoribbons oriented along Ge 〈110〉 surface directions are achieved with excellent width control and relatively large bandgaps. The bandgap magnitude and electronic uniformity of these sub-5 nm GNRs are well-suited for emerging nanoelectronic applications.

  20. Non-adiabatic Landau-Zener transitions in low-spin molecular magnet V sub 1 sub 5

    CERN Document Server

    Chiorescu, I; Müller, A; Bögge, H; Barbara, B

    2000-01-01

    The V sub 1 sub 5 polyoxovanadate molecule is made of 15 spins ((1)/(2)) with antiferromagnetic couplings. It belongs to the class of molecules with very large Hilbert space dimension (2 sup 1 sup 5 in V sub 1 sub 5 , 10 sup 8 in Mn sub 1 sub 2 -AC). It is a low spin/large molecule with spin S=((1)/(2)). Contrary to large spins/large molecules of the Mn sub 1 sub 2 -AC type, V sub 1 sub 5 has no energy barrier against spin rotation. Magnetization measurements have been performed and despite the absence of a barrier, magnetic hysteresis is observed over a timescale of several seconds. This new phenomenon characterized by a 'butterfly' hysteresis loop is due to the effect of the environment on the quantum rotation of the entangled 15 spins of the molecule, in which the phonon density of states is not at its equilibrium (phonon bottleneck).

  1. Thickness-dependent electroforming behavior of ultra-thin Ta{sub 2}O{sub 5} resistance switching layer

    Energy Technology Data Exchange (ETDEWEB)

    Park, Tae Hyung; Song, Seul Ji; Kim, Hae Jin; Hwang, Cheol Seong [Department of Materials Science and Engineering and Inter-university Semiconductor Research Center, Seoul National University, 151-744, Seoul (Korea, Republic of); Kim, Soo Gil; Chung, Suock; Kim, Beom Yong; Lee, Kee Jeung [SK Hynix Inc., 2091 Gyeongchung-daero, Bubal-eub, Icheon-si, 467-734, Gyeonggi-do (Korea, Republic of); Kim, Kyung Min [Hewlett-Packard Laboratories, Hewlett-Packard Company, Palo Alto, California, 94304 (United States); Choi, Byung Joon [Department of Materials Science and Engineering, Seoul National University of Science and Technology, Seoul, 139-743 (Korea, Republic of)

    2015-06-15

    Electroforming behaviours of Ta{sub 2}O{sub 5} resistance switching memory cell with a diameter of 28 nm and different thickness (0.5-2.0 nm) of Ta{sub 2}O{sub 5} layer have been examined. The devices showed a constant forming electric field of 0.54 V/nm regardless of Ta{sub 2}O{sub 5} thickness. The electroforming with negative bias to top TiN electrode was ascribed to electric field- driven migration of oxygen vacancies, originally residing near the bottom interface, toward the top electrode interface and formation of conducting filaments. The estimated electroforming energy (0.094-0.14 eV) was favourably compared with the hopping energy of electrons from the V{sub O} site to a nearby Ta site. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Fabrication of ultrathin films of Ta{sub 2}O{sub 5} by a sol–gel method

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, M.J., E-mail: m.wolf@fz-juelich.de [Inorganic Membranes, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Roitsch, S.; Mayer, J. [Ernst-Ruska-Centre for Microscopy and Spectroscopy with Electrons, Research Centre Jülich, 52425 Jülich (Germany); Nijmeijer, A.; Bouwmeester, H.J.M. [Inorganic Membranes, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

    2013-01-01

    Tantalum oxide (Ta{sub 2}O{sub 5}) is widely known for its high chemical, thermal and hydrothermal stability. In this study, a sol–gel method has been developed to produce homogenous, i.e., defect and pin-hole free, ultrathin films of Ta{sub 2}O{sub 5}. These were coated onto a porous substrate by means of dip-coating, and subsequently fired at 400 °C. Despite their small thickness of only 30–40 nm, the films showed very low gas permeation. - Highlights: ► Sol–gel derived defect free thin films of Ta{sub 2}O{sub 5} ► Amorphous ► Very low permeation for gases ► Only 30–40 nm ultrathin films ► Chemically, thermally and hydrothermally stable.

  3. Synthesis and characterization of polycrystalline brownmillerite cobalt doped Ca{sub 2}Fe{sub 2}O{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Dhankhar, Suchita; Baskar, K.; Singh, Shubra, E-mail: shubra6@gmail.com [Crystal Growth Centre, Anna University, Chennai-600 025 (India); Bhalerao, Gopal [UGC-DAE CSR Kalpakkam node, Kalpakkam-603104 (India)

    2016-05-23

    Brownmillerite compounds with general formula A{sub 2}BB’O{sub 5} (BB’ = Mn, Al, Fe, Co) have attracted attention in wide range of applications such as in solid oxide fuel cell, oxygen separation membrane and photocatalysis. Brownmillerite compounds have unique structure with alternate layers of BO{sub 6} octahedral layers and BO{sub 4} tetrahedral layers. Presence of dopants like Co in place of Fe increases oxygen vacancies. In the present work we have synthesized polycrystalline Ca{sub 2}Fe{sub 2}O{sub 5} and Ca{sub 2}Fe{sub 1-x}Co{sub x}O{sub 5} (x = 0.01, 0.03) by citrate combustion route. The as prepared samples were characterized by XRD using PANalytical X’Pert System, DRS (Diffuse reflectance spectroscopy) and SEM (Scanning electron microscopy).

  4. The Cardy limit of the topologically twisted index and black strings in AdS{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, Seyed Morteza; Nedelin, Anton; Zaffaroni, Alberto [Dipartimento di Fisica, Università di Milano-Bicocca,I-20126 Milano (Italy); INFN, Sezione di Milano-Bicocca,I-20126 Milano (Italy)

    2017-04-04

    We evaluate the topologically twisted index of a general four-dimensional N=1 gauge theory in the “high-temperature' limit. The index is the partition function for N=1 theories on S{sup 2}×T{sup 2}, with a partial topological twist along S{sup 2}, in the presence of background magnetic fluxes and fugacities for the global symmetries. We show that the logarithm of the index is proportional to the conformal anomaly coefficient of the two-dimensional N=(0,2) SCFTs obtained from the compactification on S{sup 2}. We also present a universal formula for extracting the index from the four-dimensional conformal anomaly coefficient and its derivatives. We give examples based on theories whose holographic duals are black strings in type IIB backgrounds AdS{sub 5}×SE{sub 5}, where SE{sub 5} are five-dimensional Sasaki-Einstein spaces.

  5. Correlating Lithium Hydroxyl Accumulation with Capacity Retention in V 2 O <sub>5 Aerogel Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Wangoh, Linda W.; Huang, Yiqing; Jezorek, Ryan L.; Kehoe, Aoife B.; Watson, Graeme W.; Omenya, Fredrick; Quackenbush, Nicholas F.; Chernova, Natasha A.; Whittingham, M. Stanley; Piper, Louis F. J.

    2016-05-11

    V2O<sub>5 aerogels are capable of reversibly intercalating more than 5 Li+/V2O<sub>5 but suffer from lifetime issues due to their poor capacity retention upon cycling. We employed a range of material characterization and electrochemical techniques along with atomic pair distribution function, X-ray photoelectron spectroscopy, and density functional theory to determine the origin of the capacity fading in V2O<sub>5 aerogel cathodes. In addition to the expected vanadium redox due to intercalation, we observed LiOH species that formed upon discharge and were only partially removed after charging, resulting in an accumulation of electrochemically inactive LiOH over each cycle. Our results indicate that the tightly bound water that is necessary for maintaining the aerogel structure is also inherently responsible for the capacity fade.

  6. Investigating the effect of V{sub 2}O{sub 5} addition on sodium barium borosilicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Halder, Rumu, E-mail: rumuhalder24feb@gmail.com; Sengupta, Pranesh; Dey, G. K. [Materials Science Division, Bhabha Atomic Research Centre, Mumbai-700 085 (India); Sudarsan, V. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai-700 085 (India); Kaushik, C. P. [Waste Management Division, Bhabha Atomic Research Centre, Mumbai-700 085 (India)

    2016-05-23

    V{sub 2}O{sub 5} doped sodium barium borosilicate glasses were characterized by photoluminescence spectroscopy and electron probe microanalyzer (EPMA). The glass remains homogeneous for lower concentration of V{sub 2}O{sub 5} but a phase separation is observed when V{sub 2}O{sub 5} doping is increased beyond 5 mol%. Detailed microanalysis reveals that the phase separated glass consists of a phase containing V, Ba and Si and a separate Si rich phase within the glass matrix. The luminescence study demonstrated that at low concentration the vanadium mainly interacts with the structural units of B/Si while at higher concentrations, V-O-V/ V-O{sup −} Na{sup +}/Ba{sup 2+} linkages are formed.

  7. Self-consistent modeling of thermal and elastic properties of unconventional superconductor PuCoGa{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Filanovich, A.N., E-mail: a.n.filanovich@urfu.ru; Povzner, A.A., E-mail: a.a.povzner@urfu.ru

    2016-06-15

    A self-consistent thermodynamic model of PuCoGa{sub 5} is developed, which for the first time takes into account the anharmonicity of both acoustic phonons, described within a Debye model, and optical phonons, considered in an Einstein approximation. Within the framework of this model, we have calculated the temperature dependencies of lattice contributions to heat capacity, bulk modulus, volumetric coefficient of thermal expansion, Debye and Einstein temperatures and their Grüneisen parameters. The electronic heat capacity of PuCoGa{sub 5} is obtained, which demonstrates an unusual temperature dependence with two maxima. In addition, it is shown that an abnormal low temperature behavior of the bulk modulus of PuCoGa{sub 5} is not caused by the effects of lattice anharmonicity and is most likely due to the valence fluctuations, which is in agreement with previous studies.

  8. Nb{sub 2}O{sub 5} hollow nanospheres as anode material for enhanced performance in lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Sasidharan, Manickam [Department of Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan); Gunawardhana, Nanda [Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan); Yoshio, Masaki, E-mail: yoshio@cc.saga-u.ac.jp [Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan); Nakashima, Kenichi, E-mail: nakashik@cc.saga-u.ac.jp [Department of Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan)

    2012-09-15

    Graphical abstract: Nb{sub 2}O{sub 5} hollow nanosphere constructed electrode delivers high capacity of 172 mAh g{sup −1} after 250 cycles and maintains structural integrity and excellent cycling stability. Highlights: ► Nb{sub 2}O{sub 5} hollow nanospheres synthesis was synthesized by soft-template. ► Nb{sub 2}O{sub 5} hollow nanospheres were investigated as anode material in Li-ion battery. ► Nanostructured electrode delivers high capacity of 172 mAh g{sup −1} after 250 cycles. ► The electrode maintains the structural integrity and excellent cycling stability. ► Nanosized shell domain facilitates fast lithium intercalation/deintercalation. -- Abstract: Nb{sub 2}O{sub 5} hollow nanospheres of average diameter ca. ∼29 nm and hollow cavity size ca. 17 nm were synthesized using polymeric micelles with core–shell–corona architecture under mild conditions. The hollow particles were thoroughly characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermal (TG/DTA) and nitrogen adsorption analyses. Thus obtained Nb{sub 2}O{sub 5} hollow nanospheres were investigated as anode materials for lithium ion rechargeable batteries for the first time. The nanostructured electrode delivers high capacity of 172 mAh g{sup −1} after 250 cycles of charge/discharge at a rate of 0.5 C. More importantly, the hollow particles based electrodes maintains the structural integrity and excellent cycling stability even after exposing to high current density 6.25 A g{sup −1}. The enhanced electrochemical behavior is ascribed to hollow cavity coupled with nanosized Nb{sub 2}O{sub 5} shell domain that facilitates fast lithium intercalation/deintercalation kinetics.

  9. Stability and isomerization reactions of phenyl cation C{sub 6}H{sub 5}{sup +} isomers

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Dandan [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun 130012 (China); Yang, Xue [College of Science, Jilin Institute of Chemical Technology, Jilin 132022 (China); Zhang, Xiaomei; Shan, Shimin [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun 130012 (China); Xu, Haifeng, E-mail: xuhf@jlu.edu.cn [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun 130012 (China); Yan, Bing, E-mail: yanbing@jlu.edu.cn [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun 130012 (China)

    2016-03-01

    Highlights: • A total of 60 isomers of C{sub 6}H{sub 5}{sup +} cations were obtained at density functional theory. • The stability and isomerization reactions of C{sub 6}H{sub 5}{sup +} isomers were performed. • The structures, frequencies, thermodynamic properties of isomers were summarized. • Ring to ring or chain isomerization pathways were investigated using IRC method. • Result shows reactions contain hydrogen transfer, bond broken and reconstruction. - Abstract: As a key polyatomic molecular cation that plays a pivotal role in growth of the polycyclic aromatic hydrocarbons, phenyl cation C{sub 6}H{sub 5}{sup +} exhibits various isomers and isomerization reactions. Investigation on the structure and stability of the isomers as well as the isomerization is important for better understanding the chemical reactions involving C{sub 6}H{sub 5}{sup +} cations. In this work, we have performed a theoretical study on the stability and isomerization reactions of C{sub 6}H{sub 5}{sup +} isomers at density functional theory B3LYP/6-311G (d, p) level. We have obtained a total of 60 isomers of C{sub 6}H{sub 5}{sup +} cations, most of which are reported for the first time. The geometries, vibrational frequencies, thermodynamic properties and stability of 28 out of 60 isomers have been summarized in detail. Different ring-to-ring and ring-to-chain isomerization pathways, which are connected via 28 transition states, have been investigated using the intrinsic reaction coordinate method. The results show that the isomerization reactions occur via hydrogen migration followed by bond-breaking and reconstruction.

  10. Open-closed superstring amplitudes using vertex operators in AdS{sub 5}×S{sup 5}

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo, Thales; Berkovits, Nathan [ICTP South American Institute for Fundamental Research,Instituto de Física Teórica, UNESP - University Estadual Paulista,Rua Dr. Bento T. Ferraz 271, 01140-070, São Paulo, SP (Brazil)

    2015-02-17

    Using the pure spinor formalism, a particular superstring scattering amplitude involving one closed string and N open string vertex operators in AdS{sub 5}×S{sup 5} is studied. It is shown that the tree-level amplitude containing one supergravity state and N super-Yang-Mills states located on D3-branes near the AdS{sub 5} boundary can be expressed as a d=4N=4 harmonic superspace integral in terms of the supergravity and super-Yang-Mills superfields.

  11. Combine selective hydrogenation and distillation to upgrade C[sub 4] and C[sub 5] streams

    Energy Technology Data Exchange (ETDEWEB)

    Barchas, R.; Samarth, R. (ABB Lummus Crest Inc., Houston, TX (United States)); Gildert, G. (Chemical Research and Licensing, Houston, TX (United States))

    Selective hydrogenation of C[sub 4] and C[sub 5] diolefins is attracting wide interest from refiners and petrochemical producers for a variety of reasons. When treating refinery and petrochemical C[sub 4] streams, selective hydrogenation increases normal butenes available for alkylation or isomerization to isobutylene, reduces acid consumption in alkylation units, and greatly improves the quality of HF alkylate. It is also a preferred processing step in the production of comonomer grade butene-1. When treating refinery C[sub 5] streams, selective hydrogenation is a required pretreatment step for TAME production and alkylation, improving product quality in both, and reducing acid consumption in the latter.

  12. Measurements of record-low residual jitter in 40-GHz monolithic mode-locked lasers

    DEFF Research Database (Denmark)

    Larsson, David; Yvind, Kresten; Hvam, Jørn Märcher

    2005-01-01

    We have performed residual phase-noise measurements on 40-GHz mode-locked lasers. The intrinsic jitter of lasers with 1, 2 and 3 QWs is compared and a minimum of 39 fs is found forthe 1-QW device.......We have performed residual phase-noise measurements on 40-GHz mode-locked lasers. The intrinsic jitter of lasers with 1, 2 and 3 QWs is compared and a minimum of 39 fs is found forthe 1-QW device....

  13. Measurement of record-low residual jitter in 40-GHz monolithic mode-locked lasers

    DEFF Research Database (Denmark)

    Larsson, David; Yvind, Kresten; Hvam, Jørn Märcher

    2005-01-01

    We have performed residual phase-noise measurements on 40-GHz mode-locked lasers. The intrinsic jitter of lasers with 1, 2 and 3 QWs is compared and a minimum of 39 fs is found for the 1-QW device.......We have performed residual phase-noise measurements on 40-GHz mode-locked lasers. The intrinsic jitter of lasers with 1, 2 and 3 QWs is compared and a minimum of 39 fs is found for the 1-QW device....

  14. Highly stable sub-5 nm Sn₆O₄(OH)₄ nanocrystals with ultrahigh activity as advanced photocatalytic materials for photodegradation of methyl orange.

    Science.gov (United States)

    Xiao, J; Wu, Q L; Liu, P; Liang, Y; Li, H B; Wu, M M; Yang, G W

    2014-04-04

    Among numerous active photocatalytic materials, Sn-based oxide nanomaterials are promising photocatalytic materials in environmental protection measures such as water remediation due to their excellent physicochemical property. Research on photocatalytic nanomaterials for photodegradation of methyl orange (MO) so far has focused on TiO₂-based nanostructures; e.g., TiO₂-P25 is recognized to be the best commercial photocatalyst to date, rather than Sn-based oxide nanomaterials, in spite of their impressive acid- and alkali-resistant properties and high stability. Here, we demonstrate very high photocatalytic activity of highly stable sub-5 nm hydromarchite (Sn₆O₄(OH)₄) nanocrystals synthesized by a simple and environmentally friendly laser-based technique. These Sn₆O₄(OH)₄ nanocrystals exhibit ultrahigh photocatalytic performance for photodegradation of MO and their degradation efficiency is far superior to that of TiO₂-P25. The detailed investigations demonstrated that the great photocatalytic activity results from the ultrafine size and unique surface activity induced by the laser-based technique. Mass production of reactive species of hydroxyl radicals was detected in the experiments due to the appropriate bandgap of Sn₆O₄(OH)₄ nanocrystals. These findings actually open a door to applications of Sn-based oxide nanomaterials as advanced photocatalytic materials.

  15. Polycrystalline ZrTe{sub 5} Parameterized as a Narrow Band Gap Semiconductor for Thermoelectric Performance.

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Samuel A.; Witting, Ian; Aydemir, Umut; Peng, Lintao; Rettie, Alex; Gorai, Prashun; Chung, Duck Young; Kanatzidis, Mercouri G.; Grayson, Matthew A.; Stevanovic, Vladan; Toberer, Eric S.; Snyder, G. Jeffery

    2018-01-24

    The transition-metal pentatellurides HfTe5 and ZrTe5 have been studied for their exotic transport properties with much debate over the transport mechanism, band gap, and cause of the resistivity behavior, including a large low-temperature resistivity peak. Single crystals grown by the chemical-vapor-transport method have shown an n-p transition of the Seebeck coefficient at the same temperature as a peak in the resistivity. We show that behavior similar to that of single crystals can be observed in iodine-doped polycrystalline samples but that undoped polycrystalline samples exhibit drastically different properties: they are p type over the entire temperature range. Additionally, the thermal conductivity for polycrystalline samples is much lower, 1.5 Wm-1 K-1, than previously reported for single crystals. It is found that the polycrystalline ZrTe<sub>5 system can be modeled as a simple semiconductor with conduction and valence bands both contributing to transport, separated by a band gap of 20 meV. This model demonstrates to first order that a simple two-band model can explain the transition from n- to p-type behavior and the cause of the anomalous resistivity peak. Combined with the experimental data, the two-band model shows that carrier concentration variation is responsible for differences in behavior between samples. Using the twoband model, the thermoelectric performance at different doping levels is predicted, finding zT =0.2 and 0.1 for p and n type, respectively, at 300 K, and zT= 0.23 and 0.32 for p and n type at 600 K. Given the reasonably high zT that is comparable in magnitude for both n and p type, a thermoelectric device with a single compound used for both legs is feasible.

  16. Hopping transport in an insulating quasicrystal bar of Al sub 7 sub 0 Pd sub 2 sub 2 sub . sub 5 Re sub 7 sub . sub 5 near the metal-insulator transition

    CERN Document Server

    Rosenbaum, R; Su, T I

    2003-01-01

    We have observed that the conductivity sigma(T) for the Al sub 7 sub 0 Pd sub 2 sub 2 sub . sub 5 Re sub 7 sub . sub 5 quasicrystal, with a resistivity ratio r = R(4.2 K)/R(300 K) = 13.2, obeys the variable-range hopping law, sigma(T) sigma sub 0 /exp [(T sub 0 /T)] supmu, in the temperature range between 64 mK and 1.6 K. The hopping exponent mu is extracted to be 0.23, close to the Mott exponent of 1/4, and T sub 0 is 3.5 K. This insulating behaviour is consistent with the prediction of a previously determined scaling law that bulk Al sub 7 sub 0 Pd sub 2 sub 2 sub . sub 5 Re sub 7 sub . sub 5 samples having r >= 12.8 will be insulating. Large positive magnetoresistances (MRs) were observed in this sample. The percentage change in the MR = DELTA R(B, T)/R(0, T), as high as 185% at T 0.11 K and B = 17 T, is the largest value ever reported in Al-Pd-Re QCs, to our knowledge. The difficulties using existing MR theories to explain the MR data for this insulating sample near the metal-insulator transition are disc...

  17. The effects of annealing temperature on the magnetic properties of Fe sub 7 sub 5 sub . sub 5 Zr sub 8 sub . sub 3 N sub 1 sub 6 sub . sub 2 /SiO sub 2 multilayer thin films

    CERN Document Server

    Kim, T S; Kim, C O; Chung, H S; Hwang, Y

    1999-01-01

    [Fe sub 7 sub 5 sub . sub 5 Zr sub 8 sub . sub 3 N sub 1 sub 6 sub . sub 2 (800 A)/SiO sub 2 (250 A)] sub 1 sub 0 multilayer thin films were fabricated by using an rf magnetron reactive sputtering method. The saturation magnetic flux density and the coercive force were measured as functions of the annealing temperature. The effective permeability at high frequencies and the thermal stability were also examined. The magnetic properties of the [Fe sub 7 sub 5 sub . sub 5 Zr sub 8 sub . sub 3 N sub 1 sub 6 sub . sub 2 (800 A)/SiO sub 2 (250 A)] sub 1 sub 0 multilayer thin films showed a saturation flux density of 1.08 T, a coercive force of 0.41 Oe, and an effective permeability of about 4000 at 1 MHz. The observed good magnetic softness is attributed to the prohibition of the growth of alpha-Fe grains due to the precipitation of nanocrystalline ZrN particles. The sizes of the alpha-Fe grains and the nanocrystalline ZrN particles were 40 approx 50 A and 10 approx 15 A, respectively. The effective permeability of...

  18. Valence band electronic structure of Nb{sub 2}Pd{sub 1.2}Se{sub 5} and Nb{sub 2}Pd{sub 0.95}S{sub 5} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Lohani, H. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400085 (India); Mishra, P. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Goyal, R.; Awana, V.P.S. [National Physical Laboratory(CSIR), Dr. K. S. Krishnan Road, New Delhi 110012 (India); Sekhar, B.R., E-mail: sekhar@iopb.res.in [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400085 (India)

    2017-03-15

    We present a comparative study of our valence band photoemission results on Nb{sub 2}Pd{sub 1.2}Se{sub 5} and Nb{sub 2}Pd{sub 0.95}S{sub 5} superconductors which are supported by our DFT based electronic structure calculations. We observe that the VB spectra of both the compounds are qualitatively similar, except for some slight differences in the binding energy positions of all the features. This could be due to the unequal electronegativities of Se and S atom. The calculated density of states (DOS) reveals that the VB features are mainly composed of Pd-Se/S hybridized states. The nature of DOS originating from the distinctly coordinated Pd atoms is different. Further, various Pd-4d and Nb-4d states crossing the Fermi level (E{sub f}) signifies the multiband character of these compounds. In addition, we find a temperature dependent pseudogap in Nb{sub 2}Pd{sub 0.95}S{sub 5} which is absent in Nb{sub 2}Pd{sub 1.2}Se{sub 5}.

  19. Anisotropy of superconducting transformation in magnetic fields in Nd sub 1 sub . sub 8 sub 5 Ce sub 0 sub . sub 1 sub 5 CuO sub 4 monocrystal

    CERN Document Server

    Panova, G K; Chernoplekov, N A; Emelchenko, G A; Malyuk, A N; Lin, S T

    2002-01-01

    The anisotropy of the superconducting properties of the Nd sub 1 sub . sub 8 sub 5 Ce sub 0 sub . sub 1 sub 5 CuO sub 4 monocrystal is studied by resistance within the temperature range of 2-30 K in the 0, 1, 2, 4, 6 Tl magnetic fields in the a-b plane. The T sub c (H) and H sub c sub 2 (T) strong anisotropy was observed by the magnetic field different orientation in the a-b plane. The zero direction in the gap of the order parameter is determined. The analysis of the experimental data shows, that such a result may be related to the change in the symmetry in the copper atoms surrounding, leading to its reduction from the tetragonal to orthorhombic one in the low-temperature area. The comparison with the La sub 1 sub . sub 8 sub 5 Sr sub 0 sub . sub 1 sub 5 CuO sub 4 gives all grounds to suppose, that the superconductivity mechanism in the electron- and hole-doped superconductor is similar and the observed difference is connected with the structure peculiarities

  20. Synthesis of Mo{sub 5}SiB{sub 2} based nanocomposites by mechanical alloying and subsequent heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi, A.R. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111, Isfahan (Iran, Islamic Republic of); Shamanian, M., E-mail: shamanian@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111, Isfahan (Iran, Islamic Republic of)

    2011-04-15

    Research highlights: {yields} {alpha}-Mo-Mo{sub 5}SiB{sub 2} nanocomposite was produced after 20 h milling of Mo-Si-B powders. {yields} Heat treatment of 5 h MAed powders led to the formation of boride phases. {yields} Heat treatment of 10 h MAed powders led to the formation of Mo{sub 5}SiB{sub 2} phase. {yields} By increasing heat treatment time, quantity of Mo{sub 5}SiB{sub 2} phase increased. {yields} 5 h heat treatment of 20 h MAed powders led to the formation of Mo{sub 5}SiB{sub 2}-based composite. - Abstract: In this study, systematic investigations were conducted on the synthesis of Mo{sub 5}SiB{sub 2}-based alloy by mechanical alloying and subsequent heat treatment. In this regard, Mo-12.5 mol% Si-25 mol% B powder mixture was milled for different times. Then, the mechanically alloyed powders were heat treated at 1373 K for 1 h. The phase transitions and microstructural evolutions of powder particles during mechanical alloying and heat treatment were studied by X-ray diffractometry and scanning electron microscopy. The results showed that the phase evolutions during mechanical alloying and subsequent heat treatment are strongly dependent on milling time. After 10 h of milling, a Mo solid solution was formed, but, no intermetallic phases were detected at this stage. However, an {alpha}-Mo-Mo{sub 5}SiB{sub 2} nanocomposite was formed after 20 h of milling. After heat treatment of 5 h mechanically alloyed powders, small amounts of MoB and Mo{sub 2}B were detected and {alpha}-Mo-MoB-Mo{sub 2}B composite was produced. On the other hand, heat treatment of 10 h and 20 h mechanically alloyed powders led to the formation of an {alpha}-Mo-Mo{sub 5}SiB{sub 2}-MoSi{sub 2}-Mo{sub 3}Si composite. At this point, there is a critical milling time (10 h) for the formation of Mo{sub 5}SiB{sub 2} phase after heat treatment wherein below that time, boride phase and after that time, Mo{sub 5}SiB{sub 2} phase are formed. In the case of 20 h mechanically alloyed powders, by

  1. Replacement of unobservable coupling DoFs in substructure decoupling

    Science.gov (United States)

    D'Ambrogio, Walter; Fregolent, Annalisa

    2017-10-01

    In this paper, suitable criteria are sought for an optimal replacement of unobservable coupling DoFs when performing substructure decoupling, that is the identification of a dynamic model of a substructure embedded in a known structure. The need arises since coupling DoFs are often difficult to observe, either because they cannot be easily accessed or because they include rotational DoFs. The substitution must be carried out both to preserve the information that would be lost when some coupling DoFs are not taken into account, and to avoid or minimize ill-conditioning problems. As shown in previous papers, coupling DoFs can be effectively replaced by internal DoFs for the sake of substructure decoupling. Furthermore, criteria for an appropriate selection of the internal DoFs used to replace unobservable coupling DoFs are sketched, which involve either the Frequency Response Function (FRF) or the transmissibility between internal and coupling DoFs. Here, previously introduced FRF and transmissibility criteria are combined with the condition number of the interface flexibility matrix to develop a procedure to optimally replace some coupling DoFs with a subset of internal DoFs. The procedure is tested using both simulated and experimental data of a tree structure (known structure), made by a cantilever beam with two offset short arms, coupled to another beam (structure to be identified).

  2. Femtosecond fiber laser additive manufacturing of tungsten

    Science.gov (United States)

    Bai, Shuang; Liu, Jian; Yang, Pei; Zhai, Meiyu; Huang, Huan; Yang, Lih-Mei

    2016-04-01

    Additive manufacturing (AM) is promising to produce complex shaped components, including metals and alloys, to meet requirements from different industries such as aerospace, defense and biomedicines. Current laser AM uses CW lasers and very few publications have been reported for using pulsed lasers (esp. ultrafast lasers). In this paper, additive manufacturing of Tungsten materials is investigated by using femtosecond (fs) fiber lasers. Various processing conditions are studied, which leads to desired characteristics in terms of morphology, porosity, hardness, microstructural and mechanical properties of the processed components. Fully dense Tungsten part with refined grain and increased hardness was obtained and compared with parts made with different pulse widths and CW laser. The results are evidenced that the fs laser based AM provides more dimensions to modify mechanical properties with controlled heating, rapid melting and cooling rates compared with a CW or long pulsed laser. This can greatly benefit to the make of complicated structures and materials that could not be achieved before.

  3. Ultrashort laser pulse–matter interaction: Implications for high ...

    Indian Academy of Sciences (India)

    2014-01-05

    Jan 5, 2014 ... writing; pump–probe technique; high-energy materials. PACS Nos 82.53.Uv; 42.62. ... hazardous materials is essential for several civilian (e.g. airport screening) and defense. (e.g. detection of land ... ies, (b) ps and fs ablation studies of plasmonic metals, (c) fs laser direct writing (LDW) studies in polymers ...

  4. FS5 sun exposure survivability analysis

    Directory of Open Access Journals (Sweden)

    Ming-Ying Hsu

    2017-01-01

    Full Text Available During the Acquisition and Safe Hold (ASH mode, FORMOAT-5 (FS5 satellite attitude is not fully controlled. Direct sun exposure on the Remote Sensing Instrument (RSI satellite telescope sensor may occur. The sun exposure effect on RSI sensor performance is investigated to evaluate the instrument’s survivability in orbit. Both satellite spin speed and sun exposure duration are considered as the key parameters in this study. A simple radiometry technique is used to calculate the total sun radiance exposure to examine the RSI sensor integrity. Total sun irradiance on the sensor is computed by considering the spectral variation effect through the RSI’s five-band filter. Experiments that directly expose the sensor to the sun on the ground were performed with no obvious performance degradation found. Based on both the analysis and experiment results, it is concluded that the FS5 RSI sensor can survive direct sun exposure during the ASH mode.

  5. Manila on CephFS at CERN

    CERN Document Server

    Wiebalck, Arne

    2017-01-01

    In response to the user demand for a light-weight provisioning of distributed file system shares, the OpenStack and Ceph teams at CERN have recently added Manila/CephFS to their service catalogues. While leveraging the operational experience with a 190'000 core OpenStack deployment and a 12 PB Ceph cluster for such a self-service kiosque suggested itself, the service design and setup phases were followed by a number of functionality and stress tests to ensure the individual components are ready for production use. The final service design and the results obtained during the pre-production phase, for instance when scaling to a large number of Manila and CephFS clients or the integration with Magnum/Kubernetes, will be presented alongside the initial use cases and our first experiences running these new services in production.

  6. High-repetition-rate regenerative thin-disk amplifier with 116 microJ pulse energy and 250 fs pulse duration.

    Science.gov (United States)

    Larionov, Mikhail; Butze, Frank; Nickel, Detlef; Giesen, Adolf

    2007-03-01

    A thin-disk regenerative amplifier based on Yb-doped potassium yttrium tungstate is operated at 40 kHz with an output pulse energy of 116 microJ and a pulse duration of 250 fs. Dispersive stretching of the pulse during amplification instead of an external stretcher is used to avoid high peak intensities. The small amount of the laser active material in the amplifier inherent for the thin-disk laser design and a large beam radius in the Pockels cell reduce nonlinear effects further. Consequently the output pulses can be compressed to 250 fs using a pair of diffraction gratings.

  7. Dual Functions of Carbon in Li(sub4)Ti(sub5)O(sub12)/C Microspheres

    CSIR Research Space (South Africa)

    Wen, L

    2015-01-01

    Full Text Available conductivity becomes a major drawback, as it is unfavorable to higher rate capability. In addition to the low electronic conductivity, severe gassing during charge/discharge cycles is a critical but often-overlooked problem of Li(sub4)Ti(sub5)O(sub12...

  8. Photobleaching phenomenon in Ge{sub 15}In{sub 5}Se{sub 80} thin films

    Energy Technology Data Exchange (ETDEWEB)

    El-Nahass, M.M. [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt); Ali, M.H. [Physics Department, Faculty of Science, Ain Shams University, Cairo (Egypt); Zedan, I.T., E-mail: islamzedan@hotmail.com [Basic Sciences Department, High Institute of Engineering and Techology, El-Arish, North Sinai (Egypt)

    2014-07-01

    This work is to explain the effect of illumination on optical properties of amorphous Ge{sub 15}In{sub 5}Se{sub 80} films in the spectral range of 200–2500 nm. The spectral distribution of transmittance (T) for the as deposited and illuminated Ge{sub 15}In{sub 5}Se{sub 80} films at different illumination times indicates a blue shift transmittance edge with exposure time (photobleaching effect). The dispersion data of the refractive index are analyzed using the concept of single oscillator model. Smakula's equation is used to calculate the concentration of color centers appear in the absorption curves. The increasing of energy gap with exposure time confirmed photoinduced bleaching in Ge{sub 15}In{sub 5}Se{sub 80} films. The effect of illumination on the non-linear optical susceptibility (χ{sup (3)}) and non-linear refractive index (n{sub 2}) is calculated using empirical relations. - Highlights: • The effect of illumination on optical properties of amorphous Ge{sub 15}In{sub 5}Se{sub 80} films. • The blue shift of transmittance edge with exposure time (photobleaching effect). • Dispersion data of the refractive index is analyzed using the concept of single oscillator model. • Energy gap increases with exposure time.

  9. Lattice energies and polarizabilities of lanthanide gallium garnets (Ln{sub 3}Ga{sub 5}O{sub 12})

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, Dimitar, E-mail: petrov_d_n@abv.bg [Department of Physical Chemistry, University of Plovdiv “Paisii Hilendarski”, 24, Tsar Asen Str., 4000 Plovdiv (Bulgaria)

    2013-04-10

    Highlights: ► The lattice energies Δ{sub L}H{sup θ} of Ln{sub 3}Ga{sub 5}O{sub 12} are determined by the Born–Haber cycle. ► The Born–Haber cycle yields the lowest values among three applied methods. ► Molar polarizations P{sub m} of Ln{sub 3}Ga{sub 5}O{sub 12} have been calculated by the Debye equation. ► The derivative (∂Δ{sub L}H{sup θ}/∂P{sub m}) corresponds to the shear moduli of these crystals. - Abstract: Lattice energies Δ{sub L}H{sup θ} of lanthanide gallium garnets Ln{sub 3}Ga{sub 5}O{sub 12} (Ln = Nd–Lu) have been determined from the Born–Haber thermochemical cycle and compared with those previously obtained by atomistic simulations in the Born model or calculated by an empirical equation. The Born–Haber cycle yields the lowest values among the three methods. Molar polarizations P{sub m} of Ln{sub 3}Ga{sub 5}O{sub 12} have been calculated by the Debye equation. It has been found that the partial derivative (∂Δ{sub L}H{sup θ}/∂P{sub m}) corresponds by magnitude to the shear moduli of these crystals.

  10. Properties of Ta{sub 2}O{sub 5} thin films prepared by ion-assisted deposition

    Energy Technology Data Exchange (ETDEWEB)

    Farhan, Mansour S. [College of Engineering, Wasit University (Iraq); Zalnezhad, E., E-mail: erfan_zalnezhad@yahoo.com [Center of Advanced Manufacturing and Material Processing, Department of Engineering Design and Manufacture, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Bushroa, A.R. [Center of Advanced Manufacturing and Material Processing, Department of Engineering Design and Manufacture, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2013-10-15

    Graphical abstract: - Highlights: • Investigating the effect of ion-beam parameters on optical properties. • Exploring the effect of ion-beam parameters on structural properties. • Studying XRD patterns of Ta{sub 2}O{sub 5} films deposited at different ion energies. - Abstract: Tantalum penta-oxide (Ta{sub 2}O{sub 5}) thin films were deposited onto highly polished and clean, fused silica glass substrates via ion beam-assisted deposition at room temperature using a high-vacuum coater equipped with an electron beam gun. The effects of ion beam parameters, oxygen flow rate, and deposition rate on the optical and structural properties as well as the stress of Ta{sub 2}O{sub 5} films were studied. It has been revealed that Ta{sub 2}O{sub 5} thin films deposited at 300 eV ion beam energy, 60 μA/cm{sup 2} ion current density, 20 sccm oxygen flow rate and 0.6 nm/s deposition rate demonstrated excellent optical, structural and compressive stress.

  11. Effect of Th-substitution in a new dense-Kondo compound UCu{sub 5}Al

    Energy Technology Data Exchange (ETDEWEB)

    Troc, R.; Andruszkiewicz, R. [Polska Akademia Nauk, Wroclaw (Poland). Inst. Niskich Temperatur i Badan Strukturalnych; Pietri, R.; Andraka, B. [Department of Physics, University of Florida, Gainesville (United States)

    1998-03-01

    We have investigated magnetic, electrical, and thermodynamic properties of a new system U{sub 1-x}Th{sub x}Cu{sub 5}Al. We have found that these alloys are antiferromagnetically ordered Kondo systems and exhibit moderate heavy fermion behaviour at low temperatures. (orig.) 1 refs.

  12. Description of the capacity degradation mechanism in LaNi{sub 5}-based alloy electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Spodaryk, Mariana, E-mail: poshtamary@ukr.net [Institute for Problems of Materials Science, NAS of Ukraine, 3, Krzhyzhanovsky Str., 03680 Kyiv-142 (Ukraine); Shcherbakova, Larisa; Sameljuk, Anatoly [Institute for Problems of Materials Science, NAS of Ukraine, 3, Krzhyzhanovsky Str., 03680 Kyiv-142 (Ukraine); Wichser, Adrian; Zakaznova-Herzog, Valentina; Holzer, Marco; Braem, Beat [EMPA Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Khyzhun, Oleg [Institute for Problems of Materials Science, NAS of Ukraine, 3, Krzhyzhanovsky Str., 03680 Kyiv-142 (Ukraine); Mauron, Philippe; Remhof, Arndt [EMPA Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Solonin, Yurii [Institute for Problems of Materials Science, NAS of Ukraine, 3, Krzhyzhanovsky Str., 03680 Kyiv-142 (Ukraine); Züttel, Andreas [EMPA Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Ecole polytechnique fédérale de Lausanne (EPFL), Institut des sciences et ingénierie chimiques, CH-1015 Lausanne (Switzerland)

    2015-02-05

    Highlights: • Morphology of gas atomised powders depends on the alloy composition. • Co substituted alloy electrodes exhibit slow activation and slow degradation. • The corrosion mechanism depends on the alloy composition and solubility of metals. - Abstract: The mechanism of the capacity degradation of LaNi{sub 5}-based alloy electrodes was investigated with a special focus on the influence of the alloy and surface composition, as well as the unique structure obtained by gas atomisation. The electrochemical properties, especially the cycle life curve (i.e. the capacity as a function of the cycle number of LaNi{sub 4.5}Al{sub 0.5}, LaNi{sub 2.5}Co{sub 2.4}Al{sub 0.1}, (La + Mm)Ni{sub 3.5}Co{sub 0.7}Al{sub 0.35}Mn{sub 0.4}Zr{sub 0.05}, and MmNi{sub 4.3}Al{sub 0.2}Mn{sub 0.5} alloy electrodes), was analysed and modelled. The capacity degradation upon cycling is determined by the chemical state of the alloy elements and the solubility of their oxides. The cycle life curves for the alloy electrodes without Co exhibited a rapid activation (3–4 cycles to reach maximum capacity), as well as rapid degradation (130–180 cycles for 50% maximum discharge capacity). LaNi{sub 2.5}Co{sub 2.4}Al{sub 0.1} and (La + Mm)Ni{sub 3.5}Co{sub 0.7}Al{sub 0.35}Mn{sub 0.4}Zr{sub 0.05} alloy electrodes activated after 7–10 cycles and showed very stable discharge behaviour (more than 400 cycles). The Co-containing alloy electrodes primarily lose the cycle stability because of mechanical decrepitation, whereas the alloys without Co suffer from selective dissolution of the unstable elements in the potential window, which was shown by our model of alloy degradation and confirmed by means of SEM, WDX, and ICP-OES data.

  13. Studies on Y{sub 2}SiO{sub 5}:Ce phosphors prepared by gel combustion using new fuels

    Energy Technology Data Exchange (ETDEWEB)

    Muresan, L.E., E-mail: laura_muresan2003@yahoo.com [“Raluca Ripan” Institute for Research in Chemistry, Babeş Bolyai University, Fântânele 30, 400294 Cluj-Napoca (Romania); Oprea, B.F.; Cadis, A.I.; Perhaita, I. [“Raluca Ripan” Institute for Research in Chemistry, Babeş Bolyai University, Fântânele 30, 400294 Cluj-Napoca (Romania); Ponta, O. [Faculty of Physics, Babeş Bolyai University, 400084 Cluj-Napoca (Romania)

    2014-12-05

    Highlights: • Y{sub 2}SiO{sub 5}:Ce was prepared by combustion using aspartic or glutamic acid as fuels. • Combustion process occurs differently depending on the fuels amount. • Single phase X2-Y{sub 2}SiO{sub 5} phosphors were obtained in fuel rich conditions. • PL measurements indicate that aspartic acid is a better fuel than glutamic. • Optimal preparative conditions were established for synthesis of Y{sub 2}SiO{sub 5}:Ce. - Abstract: Cerium activated yttrium silicate (Y{sub 2}SiO{sub 5}:Ce) phosphors were prepared by combustion, using yttrium–cerium nitrate as oxidizer, aspartic or glutamic acid as fuel and TEOS as source of silicon. In this study, aspartic and glutamic acid are used for the first time for the synthesis of Y{sub 2}SiO{sub 5}:Ce phosphors. The fuels molar amount was varied from 0.5 mol to 1.5 mol in order to reveal the thermal behavior of intermediary products (gels and ashes) same as the structural and luminescent characteristics of final products (phosphors). According to thermal analysis correlated with FTIR and XPS investigations, the combustion process occurs differently depending on the fuel amount; unreacted nitrate compounds have been identified in fuel lean conditions and carbonate based compounds along with organic residue in rich fuel conditions. The conversion to well crystallized silicates was revealed by changes of FTIR vibration bands and confirmed by XRD measurements. Based on luminescent spectra, aspartic acid is a better fuel than glutamic acid. A positive effect on the luminescence have been observed for samples fired in air due to complete remove of organic residue. The best luminescence was obtained for combustions with 0.75 mol aspartic acid and 1.25 mol glutamic respectively, fired at 1400 °C for 4 h in air atmosphere.

  14. Root colonization and growth promotion of sunflower (Helianthus annuus L.) by phosphate solubilizing Enterobacter sp. Fs-11.

    Science.gov (United States)

    Shahid, Muhammad; Hameed, Sohail; Imran, Asma; Ali, Saira; van Elsas, Jan Dirk

    2012-08-01

    An Enterobacter sp. Fs-11 was isolated from sunflower rhizosphere, identified on the basis of 16S rRNA gene sequence analysis (GeneBank accession no. GQ179978) and studied for its root colonization and growth promotion ability in sunflower. Morphologically, it was rod shaped Gram-negative, motile bacterium, producing 4.5 μg mL(-1) indole acetic acid in tryptophan-supplemented medium. It utilized 27 out of 95 substrates in BIOLOG GN2 micro plate system. It was able to convert insoluble tri-calcium phosphate to soluble phosphorus up to 43.5 μg mL(-1) with decrease in pH of the medium up to 4.5 after 10 days incubation at 28 ± 2 °C in the Pikovskaya's broth. High performance liquid chromatography of cell free supernatant showed that Fs-11 produced malic acid and gluconic acid (2.43 and 16.64 μg mL(-1), respectively) in Pikovskaya's broth. Analysis of 900 bp fragment of pyrroloquinoline quinine pqqE gene sequence showed 98 % homology with that of E. cloacae pqqE gene. Confocal laser scanning microscope revealed strong colonization of fluorescently labeled Fs-11 with sunflower roots. Sunflower inoculation with Fs-11 and its rifampicin resistant derivative in sterile sand and natural soil showed that Fs-11 colonized sunflower roots up to 30 days after transplanting in both sterile sand as well as natural soil. Moreover, Fs-11 inoculation resulted in increased plant height, fresh weight, dry weight and total phosphorus contents as compared to un-inoculated plants. The data showed that Enterobacter sp. Fs-11 is an efficient phosphate solubilizing and plant growth promoting rhizobacterium and has great potential to be used as bio-inoculant for sunflower under phosphorus deficient conditions.

  15. FS4, FS4-p, and FSP: a 4-month crossover study of 3 fine structure sound-coding strategies.

    Science.gov (United States)

    Riss, Dominik; Hamzavi, Jafar-Sasan; Blineder, Michaela; Honeder, Clemens; Ehrenreich, Isabella; Kaider, Alexandra; Baumgartner, Wolf-Dieter; Gstoettner, Wolfgang; Arnoldner, Christoph

    2014-01-01

    The aim of the present study was to compare two novel fine structure strategies "FS4" and "FS4-p" with the established fine structure processing (FSP) strategy. FS4 provides fine structure information on the apical four-electrode channels. With FS4-p, these electrodes may be stimulated in a parallel manner. The authors evaluated speech perception, sound quality, and subjective preference. A longitudinal crossover study was done on postlingually deafened adults (N = 33) who were using FSP as their default strategy. Each participant was fitted with FS4, FS4-p, and FSP, for 4 months in a randomized and blinded order. After each run, an Adaptive Sentence test in noise (Oldenburger Sentence Test [OLSA]) and a Monosyllable test in quiet (Freiburger Monosyllables) were performed, and subjective sound quality was determined with a Visual Analogue Scale. At the end of the study the preferred strategy was noted. Scores of the OLSA did not reveal any significant differences among the three strategies, but the Freiburger test showed a statistically significant effect (p = 0.03) with slightly worse scores for FS4 (49.7%) compared with FSP (54.3%). Performance of FS4-p (51.8%) was comparable with the other strategies. Both audiometric tests depicted a high variability among subjects. The number of best-performing strategies for each participant individually was as follows: (a) for the OLSA: FSP, N = 10.5; FS4, N = 10.5; and FS4-p, N = 12; and (b) for the Freiburger test: FSP, N = 14; FS4, N = 9; and FS4-p, N = 10. A moderate agreement was found in the best-performing strategies of the Speech tests within the participants. For sound quality, speech in quiet, classical, and pop music were assessed. No significant effects of strategy were found for speech in quiet and classical music, but auditory impression of pop music was rated as more natural in FSP compared with FS4 (p = 0.04). It is interesting that at the end of the study, a majority of the participants favored the new

  16. Formation of organic layer on femtosecond laser-induced periodic surface structures

    Science.gov (United States)

    Yasumaru, Naoki; Sentoku, Eisuke; Kiuchi, Junsuke

    2017-05-01

    Two types of laser-induced periodic surface structures (LIPSS) formed on titanium by femtosecond (fs) laser pulses (λ = 800 nm, τ = 180 fs, ν = 1 kHz) in air were investigated experimentally. At a laser fluence F above the ablation threshold, LIPSS with a minimum mean spacing of D organic thin film similar to a cellulose derivative that cannot be easily formed by conventional chemical synthesis. The results of these surface analyses indicate that these two types of LIPSS are formed through different mechanisms. This fs-laser processing technique may become a new technology for the artificial synthesis of cellulose derivatives.

  17. Power Laser Ablation Symposia

    CERN Document Server

    Phipps, Claude

    2007-01-01

    Laser ablation describes the interaction of intense optical fields with matter, in which atoms are selectively driven off by thermal or nonthermal mechanisms. The field of laser ablation physics is advancing so rapidly that its principal results are seen only in specialized journals and conferences. This is the first book that combines the most recent results in this rapidly advancing field with authoritative treatment of laser ablation and its applications, including the physics of high-power laser-matter interaction. Many practical applications exist, ranging from inertial confinement fusion to propulsion of aerostats for pollution monitoring to laser ignition of hypersonic engines to laser cleaning nanoscale contaminants in high-volume computer hard drive manufacture to direct observation of the electronic or dissociative states in atoms and molecules, to studying the properties of materials during 200kbar shocks developed in 200fs. Selecting topics which are representative of such a broad field is difficu...

  18. Structural characterization of K sub 3 Li sub 2 Nb sub 5 O sub 1 sub 5 single crystals by combining high-resolution X-ray diffractometry and topography

    CERN Document Server

    Kaigawa, K; Honda, A; Imaeda, M; Sakai, H; Tsurumi, T

    2002-01-01

    High-resolution multiple-crystal multiple-reflection X-ray diffractometry is used for the structural characterization of nonlinear optical single crystals of K sub 3 Li sub 2 Nb sub 5 O sub 1 sub 5 (KLN) grown by the micro-pulling-down (mu-PD) method. The combination of high-resolution X-ray diffractometry and topography shows that the lattice parameters along the c-axis (c-parameters) decrease towards the seed crystals, because of the decrease in the K content and increase in the Nb content. However, the KLN single crystals exhibit multi domain structures in which discontinuous changes in the c-parameters are periodically observed along the growth direction, despite the compositional change being continuous. Large mosaic structures due to discontinuous tilt in the lattice planes are also observed at the boundaries between the domains.

  19. Nearly constant magnetic entropy change involving two closely spaced transitions in the compound LaFe sub 1 sub 1 sub . sub 3 sub 7 sub 5 Al sub 1 sub . sub 6 sub 2 sub 5

    CERN Document Server

    Hu, F X; Wang, G J; Wang, J; Sun, J R; Zhang, X X; Cheng, Z H; Shen, B G

    2003-01-01

    A large change in the magnetic entropy, |DELTA S|, was observed in the Fe-based NaZn sub 1 sub 3 -type compound LaFe sub 1 sub 1 sub . sub 3 sub 7 sub 5 Al sub 1 sub . sub 6 sub 2 sub 5 , which was nearly temperature independent over a wide temperature range (an about 70 K span from approx 140 to 210 K). This behaviour of the magnetic entropy change is associated with two closely spaced magnetic transitions. X-ray diffraction investigation at different temperatures indicates that the crystal structure remains cubic, of NaZn sub 1 sub 3 type, when the magnetic state changes with temperature, but the cell parameter changes dramatically at the first-order transition point.

  20. Observation of three different ferromagnetic phases with predictable T sub c s in La sub 2 MnCo sub 0 sub . sub 5 Ni sub 0 sub . sub 5 O sub 6

    CERN Document Server

    Joly, V L J; Joy, P A

    2003-01-01

    The perovskite-type oxide La sub 2 MnCo sub 0 sub . sub 5 Ni sub 0 sub . sub 5 O sub 6 has been found to form in three different ferromagnetic phases with different transition temperatures, when a low-temperature synthesized sample is annealed at different temperatures. The interesting magnetic behaviour of the compound is due to the combination of different spin states of Mn, Co and Ni in the different phases of the compound. The magnetic transition temperatures of the three phases of the compound can be predicted from the T sub c s of La sub 2 MnCoO sub 6 and La sub 2 MnNiO sub 6. (letter to the editor)

  1. Monolithic Hybrid and Passive Mode-Locked 40GHz Quantum Dot Laser Diodes

    DEFF Research Database (Denmark)

    Thompson, M. G.; Larsson, David; Rae, A. R.

    2006-01-01

    For the first time hybrid and passive mode-locking jitter performance is investigated in 40GHz quantum-dot mode-locked lasers. Record low passive mode-locking jitter of 219fs is presented, along with promising hybrid mode-locking results of 124fs.......For the first time hybrid and passive mode-locking jitter performance is investigated in 40GHz quantum-dot mode-locked lasers. Record low passive mode-locking jitter of 219fs is presented, along with promising hybrid mode-locking results of 124fs....

  2. Effect of the reaction time on the microstructure and porous texture of carbon materials obtained by chlorination of Ti(C{sub 5}H{sub 5})Cl{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Araujo-Pérez, D.J. [Centro de Investigación en Micro y Nanotecnología, Universidad Veracruzana, 94294, Boca del Río, Veracruz (Mexico); González-García, P., E-mail: pedro.gonzalez@cidesi.edu.mx [CONACYT Research Fellow – Centro de Ingeniería y Desarrollo Industrial, 76130, Querétaro, Querétaro (Mexico); Poisot, M. [Instituto de Química Aplicada, Universidad del Papaloapan, 68301, San Juan Bautista Tuxtepec, Oaxaca (Mexico); García-González, L. [Centro de Investigación en Micro y Nanotecnología, Universidad Veracruzana, 94294, Boca del Río, Veracruz (Mexico)

    2015-09-15

    Carbon materials have been obtained by the chlorination reaction of Ti(C{sub 5}H{sub 5})Cl{sub 2} at 900 °C, varying the reaction time at 30, 60, 90 and 120 min. The average microstructure, studied by X ray powder diffraction, suggest that these materials consist mainly of disordered carbon with low graphitization degree (from 13.5 to 16.5%). These results are in agreement with the Raman data since the D band (at ≈ 1350 cm{sup −1}) indicates that disordered carbon networks have appeared. The calculated in-plane correlation length increases from 4.04 to 4.70 nm as the chlorination time increases from 30 to 120 min. The textural analyses reveal adsorption isotherms type 1 with hysteresis H4, microporous areas as high as 855 m{sup 2}/g and pore volume of 0.55 cm{sup 3}/g. Additionally, an important contribution of mesoporosity, around 3.6 nm, was also detected. - Highlights: • Micro-mesoporous carbon materials were obtained by chlorination of Ti(C{sub 5}H{sub 5}){sub 2}Cl{sub 2} at 900 °C. • The effect of chlorination exposure time on the microstructure and textural properties was studied. • Microstructural analysis by XRD and Raman showed that carbon samples are mainly disordered. • N{sub 2} adsorption/desorption isotherms showed isotherms type 1 with hysteresis H4. • Micropore size increases at longer chlorination time; in contrast, pore volume decreases.

  3. Study on the thermoluminescent properties of K{sub 2}YF{sub 5} and K{sub 2}GdF{sub 5} crystals doped with optically active trivalent ions for gamma and neutrons dosimetry; Estudo das propriedades termoluminescentes de cristais de K{sub 2}YF{sub 5} e K{sub 2}GdF{sub 5} dopados com ions trivalentes opticamente ativos para dosimetria gama e de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Edna Carla da

    2008-07-01

    In this work, the thermoluminescent (TL) properties of both double potassium yttrium fluoride (K{sub 2}YF{sub 5}) and double potassium gadolinium fluoride (K{sub 2}GdF{sub 5}) crystals doped with optically active rare earth ions were investigated from the point of view of gamma and neutron dosimetry. Crystalline platelets with thickness of about 1 mm, synthesized under hydrothermal conditions, were irradiated in order to study TL sensitivity, as well as dose and energy response, reproducibility and fading, in terms of Ce{sup 3+}, Tb{sup 3+}, Dy{sup 3+}, e Pr{sup 3+} concentrations. The K{sub 2}YF{sub 5} crystals doped with 1.0 at por cent Dy{sup 3+} have been found to have an excellent linear TL response to X and gamma photons, in the range of 0.01 to 10 mGy. The TL output is comparable to that of CaS0{sub 4}:Mn dosemeters. The main peak at 130 deg C has been found to have a TL response for 41.1 keV X-ray energy 32 times higher than that for 662 keV gamma rays. This fact points out that the K{sub 2}Y{sub 0.99}Dy{sub 0.01}F{sub 5} crystals have great potential for X-rays diagnostic and/or industrial radiography. On the other hand, the K{sub 2}GdF{sub 5} crystals doped with 5.0 at por cent Dy{sup 3+} have been found to have the better TL response for gamma and fast neutron radiation, among the dopants studied. For gamma fields the TL response was linear for doses ranging from 0.1 to 200 mGy. The TL peak around 200 deg C can be deconvoluted into four individual peaks, all of them with linear behavior. For fast neutron radiation produced by an {sup 241}Am{sub B}e source, the TL responses for doses ranging from 0.6 to 12 mSv were also linear and comparable to that of commercial TLD-600, irradiated at same conditions. The TL emission due to neutrons was in the high temperature range, above 200 deg C. These results points out that K{sub 2}Gd{sub 0.95}Dy{sub 0.05}F{sub 5} crystals are good candidates for use in neutron dosimetry applications. (author)

  4. Vibration assisted femtosecond laser machining on metal

    Science.gov (United States)

    Park, Jung-Kyu; Yoon, Ji-Wook; Cho, Sung-Hak

    2012-06-01

    We demonstrate a novel approach to improve laser machining quality on metals by vibrating the optical objective lens with a frequency (of 500 Hz) and various displacements (0-16.5 μm) during a femtosecond laser machining process. The laser used in this experiment is an amplified Ti:sapphire fs laser system that generates 100 fs pulses having an energy of 3.5 mJ/pulse with a 5 kHz repetition rate at a central wavelength of 790 nm. It is found that both the wall surface finish of the machined structures and the aspect ratio obtained using the frequency vibration assisted laser machining are improved, compared to those derived via laser machining without vibration assistance. This is the first report of low frequency vibration of an optical objective lens in the femtosecond laser machining process being exploited to obtain significantly improved surface roughness of machined side walls and increased aspect ratios.

  5. Synthesis and characterization of Nb{sub 2}O{sub 5} by a colloidal route; Sintese e caracterizacao de Nb{sub 2}O{sub 5} por rota coloidal

    Energy Technology Data Exchange (ETDEWEB)

    Falk, G.S.; Borlaf, M.; Oliveira, A.P. Novaes de; Rodrigues Neto, J.B.; Hotza, D., E-mail: gilbertofalk@outlook.com [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Moreno, R. [Instituto de Ceramica y Vidrio, Consejo Superior de Investigaciones Cientificas, Madri (Spain)

    2014-07-01

    The niobium pentoxide (Nb{sub 2}O{sub 5}) is known to be a polymorphic ceramic semiconductor and display features, which makes it a potential candidate in the field of photocatalysis. In this paper, we evaluate a colloidal route for the synthesis of Nb{sub 2}O{sub 5}. The properties of the suspension and the powder obtained were determined by analysis of particle size, zeta potential, thermogravimetric and differential thermal analysis (TG-DTA) and X-ray diffraction (XRD). The results indicated that the particle size was 0.3 μm and at pHs between 8 and 9, stable suspensions were obtained. Through the XRD results it was observed that the synthesized powder is amorphous and that at 300°C/1h niobic acid (HNbO{sub 3}) crystallizes, which after calcination at 450, 650, 850 and 1050 deg C/1h, turns into Nb{sub 2}O{sub 5} with different crystalline structures. (author)

  6. Growth and characteristics of (TbBi){sub 3}(FeAlGa){sub 5}O{sub 12} and (EuBi){sub 3}(FeAlGa){sub 5}O{sub 12} garnet single crystal thick films

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, S.G.; Kim, G.Y.; Kim, Y.T.; Kim, M.J.; Im, Y.M.; Yoon, D.H

    2003-12-15

    The single crystalline thick films of (TbBi){sub 3}(FeAlGa){sub 5}O{sub 12} (TbIG) and (EuBi){sub 3}(FeAlGa){sub 5}O{sub 12} (EuIG) garnet single crystal thick films were grown on (GdCa){sub 3}(GaMgZr){sub 5}O{sub 12} (SGGG) substrate by liquid phase epitaxy (LPE). The lattice constant and lattice mismatch of TbIG were 12.507 A and 118.8 arcsec and those of EuIG were 12.489 A and 75.6 arcsec (SGGG=12.496 A), respectively. The magnetic-domain could be observed in the EuIG film after the removal of the magnetic field. The Bi-substitution level of the TbIG films was increased as compared to the EuIG films. Also saturation magnetization of TbIG and EuIG films get 150 and 950 Oe, respectively.

  7. Growth and characterization of V{sub 2}O{sub 5} nanorods deposited by spray pyrolysis at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Abd-Alghafour, N. M., E-mail: na2013bil@gmail.com; Ahmed, Naser M., E-mail: nas-tiji@yahoo.com; Hassan, Zai. [Iraqi Ministry of Education, Anbar-Iraq (Iraq); Mohammad, Sabah M. [Nano-Optoelectronics Research and Technology Laboratory School of Physics, university sains Malaysia, 11800 Penang (Malaysia); Bououdina, M. [Nanotechnology Centre, University of Bahrain, PO Box 32038, Kingdom of Bahrain Department of Physics, College of Science, University of Bahrain, PO Box 32038, Kingdom of Bahrain, Iraqi Ministry of Education (Bahrain)

    2016-07-06

    Vanadium pentoxide (V{sub 2}O{sub 5}) nanorods were deposited by spray pyrolysis on preheated glass substrates at low temperatures. The influence of substrate temperature on the crystallization of V{sub 2}O{sub 5} has been investigated. X-ray diffraction analysis (XRD) revealed that the films deposited at T{sub sub} = 300°C were orthorhombic structures with preferential along (001) direction. Formation of nanorods from substrate surface which led to the formation of films with small-sized and rod-shaped nanostructure is observed by field scanning electron microscopy. Optical transmittance in the visible range increases to reach a maximum value of about 80% for a substrate temperature of 350°C. PL spectra reveal one main broad peak centered around 540 nm with high intensity.

  8. Nonlinear transport in quasi-one-dimensional Nb{sub 2}PdS{sub 5} nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Ning, Wei; Yu, Hongyan; Wang, Ning; Han, Yuyan; Yang, Jiyong; Du, Haifeng; Zhang, Changjin [High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, Anhui (China); Liu, Yequn [Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Yang, Kun [National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306-4005 (United States); Tian, Mingliang, E-mail: tianml@hmfl.ac.cn; Zhang, Yuheng [High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, Anhui (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093 (China)

    2014-10-27

    Nb{sub 2}PdS{sub 5} is a newly discovered quasi-one-dimensional (quasi-1D) superconductor with a high upper critical field along the chain direction. Here, we report the size-dependent electronic properties of Nb{sub 2}PdS{sub 5} nanowires obtained by ultrasonically cleaving the bulk crystals. The nanowires exhibit a superconductor to insulator transition as the cross-sectional area decreases. Moreover, for the thinner nanowires with insulating state, the transport properties exhibit a power-law dependence on both temperature and bias voltage at an intermediate temperature (<30 K), followed by a conduction saturation below 10 K. We found that such an apparent power-law behavior can be described by the extended variable range hopping theory developed recently for the multichannel quasi-1D systems, where the localization of electrons is expected to be dominant instead of the Luttinger liquid nature.

  9. Preemiad said Rein Raud, fs, Mart Kivastik

    Index Scriptorium Estoniae

    2005-01-01

    Eesti Kultuurkapitali 2004. aasta kirjanduse aastapreemia laureaadid on: Rein Raud ("Hector ja Bernard"), fs (luulekogu "2004"), Mart Kivastik (näidend "Külmetava kunstniku portree"), Jaan Rannap ("Nelja nimega koer"), Toomas Haug ("Troojamäe tõotus"), Harald Rajamets (tõlkeluule kogumik "Pegasos ja peegel"), Antoine Chalvin ("Kalevipoja" tõlge prantsuse keelde"), Ilmar Talve ("Eesti kultuurilugu"), Lauri Sommer (artikkel Uku Masingu käsikirja "Saadik Magellani pilvest" vaimne, ajalis-ruumiline ja elulooline taust), Boris Tuch ("Gorjatshaja desjatka estonskihh pisatelei")

  10. Ultrashort laser pulse driven inverse free electron laser accelerator experiment

    Directory of Open Access Journals (Sweden)

    J. T. Moody

    2016-02-01

    Full Text Available In this paper we discuss the ultrashort pulse high gradient inverse free electron laser accelerator experiment carried out at the Lawrence Livermore National Laboratory which demonstrated gradients exceeding 200  MV/m using a 4 TW 100 fs long 800 nm Ti:Sa laser pulse. Due to the short laser and electron pulse lengths, synchronization was determined to be one of the main challenges in this experiment. This made necessary the implementation of a single-shot, nondestructive, electro-optic sampling based diagnostics to enable time-stamping of each laser accelerator shot with <100  fs accuracy. The results of this experiment are expected to pave the way towards the development of future GeV-class IFEL accelerators.

  11. Ground state of Er sup 3+ ions in ErNi sub 5 as studied by high field magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Radwanski, R.J.; Franse, J.J.M.; Kayzel, F.E.; Marquina, C. (Van der Waals-Zeeman Lab., Univ. Amsterdam (Netherlands)); Gignoux, D. (Lab. Louis Neel, CNRS, 38 - Grenoble (France)); Szewczyk, A. (Inst. of Physics of Polish Academy of Sciences, Warszaw (Poland))

    1992-03-01

    By magnetization studies of single crystalline ErNi{sub 5} in magnetic fields up to 35 T, the crystal field and exchange interactions have been evaluated. The ground state of the Er{sup 3+} ion is found to be a {Gamma}{sub 9} doublet with a dominant vertical stroke{+-}15/2> contribution. The derived parameters describe the inelastic neutron scattering and specific heat results available in the literature very well. (orig.).

  12. On semiclassical analysis of pure spinor superstring in an AdS{sub 5} x S{sup 5} background

    Energy Technology Data Exchange (ETDEWEB)

    Aisaka, Yuri [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Sao Paulo State Univ. (Brazil). Inst. de Fisica Teorica; Ibiapina Bevilaqua, L. [Univ. Federal do Rio Grande do Norte, Natal (Brazil). Esola de Ciencias e Tecnologia; Vallilo, Brenno C. [Santiago Univ. (Chile). Dept. de Ciencias Fisicas

    2012-06-15

    Relation between semiclassical analyses of Green-Schwarz and pure spinor formalisms in an AdS{sub 5} x S{sup 5} background is clarified. It is shown that the two formalisms have identical semiclassical partition functions for a simple family of classical solutions. It is also shown that, when the classical string is furthermore rigid, this in turn implies that the two formalisms predict the same one-loop corrections to spacetime energies.

  13. Nature of unusual spontaneous and field-induced phase transitions in multiferroics RMn{sub 2}O{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Pyatakov, A.P. [Physics Department, M.V. Lomonosov MSU, Leninskie gori, Moscow 119992 (Russian Federation); A. M. Prokhorov General Physics Institute, 38, Vavilova street, Moscow 119991 (Russian Federation)], E-mail: pyatakov@phys.msu.ru; Kadomtseva, A.M.; Vorob' ev, G.P.; Popov, Yu.F.; Krotov, S.S. [Physics Department, M.V. Lomonosov MSU, Leninskie gori, Moscow 119992 (Russian Federation); Zvezdin, A.K. [A. M. Prokhorov General Physics Institute, 38, Vavilova street, Moscow 119991 (Russian Federation); Fondazione ISI, 10133 Torino (Italy); Lukina, M.M. [Physics Department, M.V. Lomonosov MSU, Leninskie gori, Moscow 119992 (Russian Federation)

    2009-04-15

    Complex magnetic, magnetoelectric and magnetoelastic studies of spontaneous and field-induced phase transitions in TmMn{sub 2}O{sub 5} were carried out. In the vicinity of spontaneous phase transition temperatures (35 and 25 K) the magnetoelectric and magnetoelastic dependences demonstrated the jumps of polarization and magnetostriction induced by the field {approx}150 kOe. These anomalies can be attributed to the influence of magnetic field on the conditions of incommensurate-commensurate phase transition at 35 K and the reverse one at 25 K. In b-axis dependences the magnetic field-induced spin-reorientation phase transition was also observed below 20 K. Finally the magnetoelectric anomaly associated with metamagnetic transition is observed below the temperature of rare-earth subsystem ordering at relatively small critical fields of 5 kOe. This variety of spontaneous and induced phase transitions in RMn{sub 2}O{sub 5} stems from the interplay of three magnetic subsystems: Mn{sup 3+}, Mn{sup 4+}, R{sup 3+}. The comparison with YMn{sub 2}O{sub 5} highlights the role of rare earth in low-temperature region (metamagnetic and spin-reorientation phase transitions), while the phase transition at higher temperatures between incommensurate and commensurate phases should be ascribed to the different temperature dependences of Mn{sup 3+} and Mn{sup 4+} ions. The strong correlation of magnetoelastic and magnetoelectric properties observed in the whole class of RMn{sub 2}O{sub 5} highlights their multiferroic nature.

  14. fs - kes ta on ja kust ta tuleb : [luuletused] / [Mesikepp, Indrek] fs

    Index Scriptorium Estoniae

    fs, pseud., 1971-

    2004-01-01

    Sisu: fs - kes ta on ja kust ta tuleb ; "töötasin arhiivis..." ; mustad puud mustas vees ; "on päev. on kylm. on öö..." ; "tead ju kyll..." ; "päiksest paistes päevad..." ; "mida sa teed kui on öö..."

  15. Luminescent properties of Ce{sup 3+}ions in Ca {sub 2}B {sub 5}O {sub 9}Cl

    Energy Technology Data Exchange (ETDEWEB)

    Dotsenko, V.P.; Berezovskaya, I.V.; Efryushina, N.P.; Shabanov, E.V. [A.V. Bogatsky Physico-Chemical Institute, Ukrainian Academy of Sciences, Lustdorfskaya doroga 86, 65080 Odessa (Ukraine); Voloshinovskii, A.S. [Lviv Franko State University, Kirilo i Mefodii 8, 79005 Lviv (Ukraine)

    2006-04-15

    The luminescent properties of Ce{sup 3+} ions in Ca{sub 2}B{sub 5}O{sub 9}Cl have been studied upon excitation in the 3.5-25 eV region. The energies of all 5d crystal field levels of Ce{sup 3+} ions in double doped Ca{sub 2}B{sub 5}O{sub 9}Cl:Ce{sup 3+}, Na{sup +} have been determined. In addition to the 4f {yields} 5d excitation bands, the excitation spectrum of the Ce{sup 3+} emission shows a band with a maximum at 7.7 eV, which is attributed to the absorption of the borate groups. The influence of the structural features of Ca{sub 2}B{sub 5}O{sub 9}Cl on the luminescent behavior of Ce{sup 3+} is discussed. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Thermodynamics and kinetics of decomposition of Al{sub 2}TiO{sub 5}-base ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Buscaglia, V.; Leoni, M. [CNR, Genoa (Italy). ICFAM; Nanni, P. [Facolta di Ingegneria, Univ. di Genova (Italy)

    1997-12-31

    The decomposition of Mg{sub x}Al{sub 2(1-x)}Ti{sub (1+x)}O{sub 5} solid solutions with x = 0 (Al{sub 2}TiO{sub 5}), 0.1 and 0.2 was studied at 1100 C. The kinetics follows the Avrami equation with a time exponent of 1.6 for x = 0 and 3/3.5 for x = 0.1 and 0.2. Decomposition of materials with x > 0 is considerably delayed in comparison to pure Al{sub 2}TiO{sub 5}: the time of half-transformation into parent oxides is increased by an order of magnitude. The microstructure of partially decomposed materials show the presence of nodules with a core composed of Al{sub 2}O{sub 3} (and MgAl{sub 2}O{sub 4} when x > 0) elongated crystal, surrounded by an irregular TiO{sub 2} shell. The nodules grow retaining their structure as decomposition proceeds. The decomposition kinetics is probably controlled by the nucleation of the reaction product at a limited number of ``easy to nucleate`` sites owing to the small chemical driving force available. (orig.) 11 refs.

  17. Crystal structure of the oxygen conducting compound Nd{sub 5}Mo{sub 3}O{sub 16}

    Energy Technology Data Exchange (ETDEWEB)

    Alekseeva, O.A.; Sorokina, N.I.; Bolotina, N.B.; Artemov, V.V. [Russian Academy of Sciences, Moscow (Russian Federation). Shubnikov Institute of Crystallography; Gagor, A.B.; Pietraszko, A.P. [Polish Academy of Sciences, Wroclaw (Poland). W. Trzebiatowski Institute of Low Temperature and Structure Research; Kharitonova, E.P.; Voronkova, V.I. [Moscow State Univ., Moscow (Russian Federation)

    2012-07-01

    Structure of the Nd{sub 5}Mo{sub 3}O{sub 16} single crystal grown in the Nd{sub 2}O{sub 3}-MoO{sub 3} system was studied using the X-rays diffraction technique at 293 K and 110 K temperatures. The unit-cell values were always cubic relating to that of CaF{sub 2} fluorite as a {approx} 2a{sub f} (a{sub f} = 5.5 Aa). The structure was solved within the Pn anti 3n symmetry group. It was found that the Nd{sub 5}Mo{sub 3}O{sub 16} compound has a fluorite-like structure with all atoms disordered. An indirect confirmation for the violation of translational periodicity in the distribution of Mo and Nd atoms was obtained. The possible oxygen diffusion paths were analyzed using the one-particle potentials of the oxygen atoms. The ionic conductivity of Nd{sub 5}Mo{sub 3}O{sub 16} compound is associated with the disordering of the oxygen atoms in several positions, and their deficiency in comparison with the initial fluorite. (orig.)

  18. Crystal growth, structure, magnetic properties and theoretical exchange interaction calculations of Cu{sub 2}MnBO{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Sofronova, S. [L.V. Kirensky Institute of Physics, Siberian Branch of Russian Academy of Science, 660036 Krasnoyarsk (Russian Federation); Moshkina, E. [L.V. Kirensky Institute of Physics, Siberian Branch of Russian Academy of Science, 660036 Krasnoyarsk (Russian Federation); M V Reshetnev Siberian State Aerospace University, 660014 Krasnoyarsk (Russian Federation); Nazarenko, I. [L.V. Kirensky Institute of Physics, Siberian Branch of Russian Academy of Science, 660036 Krasnoyarsk (Russian Federation); Seryotkin, Yu. [V.S. Sobolev Institute of Geology and Mineralogy, SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation); Nepijko, S.A. [Institute of Physics, University of Mainz, 55099 Mainz (Germany); Ksenofontov, V. [Institute of Inorganic and Analytical Chemistry, University of Mainz, 55099 Mainz (Germany); Medjanik, K. [Lund University, MAX IV Laboratory, 22100 Lund (Sweden); Veligzhanin, A. [National Research Centre “Kurchatov Institute”, 123182 Moscow (Russian Federation); Bezmaternykh, L. [L.V. Kirensky Institute of Physics, Siberian Branch of Russian Academy of Science, 660036 Krasnoyarsk (Russian Federation)

    2016-12-15

    Single crystals of ludwigite Cu{sub 2}MnBO{sub 5} were synthesized by flux growth technique. The detailed structural and magnetic characterizations of the synthesized samples have been carried out. The cations composition of the studied crystal was determined using X-ray diffraction and EXAFS technique, the resulting composition differ from the content of the initial Mn{sub 2}O{sub 3}–CuO components of the flux. Magnetic susceptibility measurements and the calculations of the exchange integrals in frameworks of indirect coupling model revealed that monoclinic distortions strongly affect exchange interactions and appearance of magnetic ordering phase at the temperature T=93 K. The hypothesis of the existence of several magnetic subsystems was supposed. - Highlights: • Single crystals of ludwigite Cu{sub 2}MnBO{sub 5} were synthesized. • Structural characterization was carried out by the X-ray diffraction and EXAFS technique. • Cations composition was determined by X-ray diffraction and EXAFS technique. • Cu{sub 2}MnBO{sub 5} magnetic behavior was analyzed in frameworks of indirect coupling model.

  19. Effect of nickel seed layer on growth of α-V{sub 2}O{sub 5} nanostructured thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Rabindar Kumar; Kant, Chandra; Kumar, Prabhat; Singh, Megha, E-mail: meghasingh-08@yahoo.com; Reddy, G. B. [Thin film Laboratory, Department of Physics, Indian Institute of Technology Delhi-110016 (India)

    2015-08-28

    In this communication, we reported the role of Ni seed layer on the growth of vanadium pentoxide (α-V{sub 2}O{sub 5}) nanostructured thin films (NSTs) using plasma assisted sublimation process (PASP). Two different substrates, simple glass substrate and the Ni coated glass substrate (Ni thickness ∼ 100 nm) are employing in the present work. The influence of seed layer on structural, morphological, and vibrational properties have been studied systematically. The structural analysis divulged that both films deposited on simple glass as well as on Ni coated glass shown purely orthorhombic phase, no other phases are detected. The morphological studies of V{sub 2}O{sub 5} film deposited on both substrates are carried out by SEM, revealed that features of V{sub 2}O{sub 5} NSTs is completely modified in presence of Ni seed layer and the film possessing the excellent growth of nanorods (NRs) on Ni coated glass rather than simple glass. The HRTEM analysis of NRs is performed at very high magnification, shows very fine fringe pattern, which confirmed the single crystalline nature of nanorods. The vibrational study of NRs is performed using micro-Raman spectroscopy, which strongly support the XRD observations.

  20. High-power 200 fs Kerr-lens mode-locked Yb:YAG thin-disk oscillator.

    Science.gov (United States)

    Pronin, O; Brons, J; Grasse, C; Pervak, V; Boehm, G; Amann, M-C; Kalashnikov, V L; Apolonski, A; Krausz, F

    2011-12-15

    We demonstrate a power-scalable Kerr-lens mode-locked Yb:YAG thin-disk oscillator. It delivers 200 fs pulses at an average power of 17 W and a repetition rate of 40 MHz. At an increased (180 W) pump power level, the laser produces 270 fs 1.1 μJ pulses at an average power of 45 W (optical-to-optical efficiency of 25%). Semiconductor-saturable-absorber-mirror-assisted Kerr-lens mode locking (KLM) and pure KLM with a hard aperture show similar performance. To our knowledge, these are the shortest pulses achieved from a mode-locked Yb:YAG disk oscillator and this is the first demonstration of a Kerr-lens mode-locked thin-disk laser.

  1. Pressure Monitoring Using Hybrid fs/ps Rotational CARS

    Science.gov (United States)

    Kearney, Sean P.; Danehy, Paul M.

    2015-01-01

    We investigate the feasibility of gas-phase pressure measurements at kHz-rates using fs/ps rotational CARS. Femtosecond pump and Stokes pulses impulsively prepare a rotational Raman coherence, which is then probed by a high-energy 6-ps pulse introduced at a time delay from the Raman preparation. Rotational CARS spectra were recorded in N2 contained in a room-temperature gas cell for pressures from 0.1 to 3 atm and probe delays ranging from 10-330 ps. Using published self-broadened collisional linewidth data for N2, both the spectrally integrated coherence decay rate and the spectrally resolved decay were investigated as means for detecting pressure. Shot-averaged and single-laser-shot spectra were interrogated for pressure and the accuracy and precision as a function of probe delay and cell pressure are discussed. Single-shot measurement accuracies were within 0.1 to 6.5% when compared to a transducer values, while the precision was generally between 1% and 6% of measured pressure for probe delays of 200 ps or more, and better than 2% as the delay approached 300 ps. A byproduct of the pressure measurement is an independent but simultaneous measurement of the gas temperature.

  2. Femtosecond laser refractive surgery: small-incision lenticule extraction vs. femtosecond laser-assisted LASIK.

    Science.gov (United States)

    Lee, Jimmy K; Chuck, Roy S; Park, Choul Yong

    2015-07-01

    Small-incision lenticule extraction (SMILE) is a novel technique devised to correct refractive errors. SMILE circumvents excimer laser photoablation of cornea, as the stromal lenticule cut by femtosecond laser is removed manually. Smaller incisions and preservation of anterior corneal biomechanical strength have been suggested as some of the advantages of SMILE over femtosecond laser-assisted LASIK (FS-LASIK). In this review, we compared previous published results of SMILE and FS-LASIK. The advantage, efficacy and safety of SMILE are compared with FS-LASIK. SMILE achieved similar efficacy, predictability and safety as FS-LASIK. Greater preservations of corneal biomechanical strength and corneal nerves were observed in SMILE when compared with LASIK or PRK. Additionally, the incidence of postoperative dry eye syndrome was found to be less problematic in SMILE than in FS-LASIK. SMILE is a promising new surgery for refractive error correction. Prospective and retrospective studies of SMILE have shown that results of SMILE are similar to FS-LASIK. With advances in femtosecond laser technology, SMILE may gain greater acceptance in the future.

  3. Nielsen: Aladdin-Suite, FS89. Maskarade-Overture / Robert Layton

    Index Scriptorium Estoniae

    Layton, Robert

    1996-01-01

    Uuest heliplaadist "Nielsen: Aladdin-Suite, FS89. Maskarade-Overture, Prelude, Act 2. The Cockerels' Dance. Rhapsody Overture: An imaginary journey to the Faroe Islands, FS123. Helios Overture, FS32. Saga-Drom, FS46. Pan and Syrinx, FS87. Gothenburg Symphony Orchestra, Neeme Järvi" DG 447 757-2GH (72 minutes: DDD)

  4. 700 MW peak power of a 380 fs regenerative amplifier with Tm:YAP.

    Science.gov (United States)

    Wienke, Andreas; Wandt, Dieter; Morgner, Uwe; Neumann, Jörg; Kracht, Dietmar

    2015-06-29

    We report on a high power ultrashort pulse regenerative amplifier system, entirely based on thulium-doped laser materials operating around 1.94 μm. At a repetition rate of 1 kHz the Tm:YAP regenerative amplifier emits pulse energies > 700 μJ, only limited by the damage threshold of the Tm:YAP crystal. The pulses can be compressed to 380 fs at an efficiency of 50 %. Purging of the regenerative amplifier cavity with nitrogen is necessary due to atmospheric absorptions causing long ps pedestals in the autocorrelation.

  5. Effect of the milling time on thermal stability of mechanically alloyed Mg{sub 5}0 Ni{sub 5}0 amorphous alloy; Efecto del tiempo de molienda sobre la estabilidad termica del amorfo Mg{sub 5}0 Ni:50 producido mediante aleado mecanico

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, D.; Ordonez, S.; Serafini, D.; Rojas, P.; Aguilar, C.; Santander, M.; Navea, L.

    2009-07-01

    In order to study the relationship between the milling time used in the production of Mg{sub 5}0Ni{sub 5}0 amorphous alloy and its thermal stability, seven amorphous alloys were produced by milling for 20, 25, 30, 35, 40, 50 and 60 h each sample. The obtained powders were morphological and structurally characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The thermal stability of amorphous alloys was study by differential scanning calorimetry (DSC). Based on the obtained results, it can be concluded that the increase in the added energy when milling for longer time causes the homogenization of the microstructure with an increase in amorphous phase, which dissolves a large amount of nickel in its structure. Therefore, the simultaneous crystallization of the Mg{sub 2}Ni and MgNi{sub 2} intermetallic compounds at 345 degree centigrade can be explained. (Author) 19 refs.

  6. Microstructures of the oxides on the activated AB{sub 2} and AB{sub 5} metal hydride alloys surface

    Energy Technology Data Exchange (ETDEWEB)

    Young, K., E-mail: kwo.young@BASF.com [BASF/Battery Materials-Ovonic, 2983 Waterview Drive, Rochester Hills, MI 48309 (United States); Chao, B. [BASF/Battery Materials-Ovonic, 2983 Waterview Drive, Rochester Hills, MI 48309 (United States); Liu, Y. [Electron Microscopy Facility, 145 Linus Pauling Science Center, 2900 SW Campus Way, Oregon State University, Corvallis, OR 97331 (United States); Nei, J. [BASF/Battery Materials-Ovonic, 2983 Waterview Drive, Rochester Hills, MI 48309 (United States)

    2014-09-01

    Highlights: • Morphologies of surface hydroxide of AB{sub 2}, AB{sub 5}, and A{sub 2}B{sub 7} alloys were compared. • Nd promotes the formation of thick rod instead of fine needles. • Both AB{sub 2} and AB{sub 5} show similar buffer oxide + surface oxide structure. • The surface oxide layers in AB{sub 2} are thicker than those from AB{sub 5}. • AB{sub 2} surface is covered by oxide with less solubility in KOH. - Abstract: The surface oxides of the activated metal hydride alloys used as the negative electrode for nickel–metal hydride battery were studied by both scanning and transmission electron microscope techniques. In transition metal based AB{sub 2} metal hydride alloys, the surface of the powder is covered with oxides as a product of oxidation from the electrolyte and protected by zirconium oxide and vanadium-rich BCC-structured secondary phase. In the rare-earth based AB{sub 5} and A{sub 2}B{sub 7} metal hydride alloys, the surface is decorated with nano-structured needles and larger-scaled rods of hydroxides from the precipitation of rare earth ions after the oxidation by the electrolyte. Further TEM studies show the existence of a buffer oxide layer sandwiched between the inclusion-embedded surface oxide and alloy bulk in both AB{sub 2} and AB{sub 5} alloys. In both cases, the inclusions are found to be metallic nanocrystals mainly composed of Ni and Co as determined by electron energy loss spectroscopy, selective area electron diffraction, transmission electron atomic image, and X-ray energy dispersive spectroscopy. The Co-to-Ni ratio in the inclusion is larger than that in the bulk due to the less corrosive nature of Co. The additions of Co and Al in the AB{sub 2} are found to reduce number of activation cycles needed to generate a surface oxide with proper catalytic capability.

  7. Hydrosilation of the manganese acetyl (CO){sub 5}MnC(O)CH{sub 3} with monohydrosilanes

    Energy Technology Data Exchange (ETDEWEB)

    Gregg, B.T.; Cutler, A.R. [Rensselaer Polytechnic Inst., Troy, NY (United States)

    1996-10-23

    Treatment of the manganese acetyl (CO){sub 5}MnC(O)CH{sub 3} (1) with 1-2 equiv of a monohydrosilane furnished mixtures of {alpha}-siloxyethyl (CO){sub 5}MnCH(OSiR{sub 3})CH{sub 3} (2) and {alpha}-siloxyvinyl (CO){sub 5}MnC(OSiR{sub 3})=CH{sub 2} (3) complexes. Relative yields of 2 and 3 varied from 80% and 6% for HSiMe{sub 2}Ph to 28% and 59% for HSiEt{sub 3}. Mechanistic studies on the HSiMe{sub 2}Ph and HSiEt{sub 3} hydrosilation of 1 are noteworthy for (1) the absence of (R{sub 3}SiO)CH=CH{sub 2} and CH{sub 3}CH{sub 2}OSiR{sub 3} byproducts, (2) the presence of 3 but not (CO){sub 5}MnSiR{sub 3}, (3) inhibition by CO, phosphine, or acetonitrile, but neither air nor light, (4) competitive hydrosilation of other substrates (e.g., acetone or Cp(CO){sub 2}FeC(O)R) for which 1 is a precatalyst, (5) degradation of 2 by excess HSiR{sub 3}, giving Mn{sub 2}(CO){sub 10} and (R{sub 3}Si){sub 2}O as the final products, (6) the fact that this degradation results in autocatalysis by generating the transient active catalyst (CO){sub 4}MnSiR{sub 3} (15), and (7) the fact that the hydrosilation induction period can be removed by independently generating the putative 15. These observations are consistent with an autocatalytic hydrosilation mechanism in which silane degradation of product 2 (or of other manganese complexes) generates the active catalyst 15, which binds 1 and rearranges to the unsaturated bimetallic {mu}-siloxyethylidene (CO){sub 5}MnC(CH{sub 3})(OSiMe{sub 2}Ph)Mn(CO){sub 4} as the key catalysis intermediate: silane addition affords 2 whereas {beta}-deinsertion produces 3. 54 refs., 4 figs., 2 tabs.

  8. Ultrafast lasers in ophthalmology

    Science.gov (United States)

    Lubatschowski, Holger

    Ultrafast laser pulses have become a promising tool for microsurgery of the eye. Due to the low energy threshold, side effects are limited to the micrometer range This precision enables the use of ultrashort laser pulses in a broad field of medical applications. Especially, the interaction process based on nonlinear absorption offers the opportunity to process transparent tissue not only on top of a surface but three dimensionally inside the bulk. This mechanism is used in refractive eye surgery, where fs pulses create flaps into the corneal tissue to remodel the curvature of the eye and to improve visual acuity. Moreover, fs pulses could be used to influence the biomechanics of the crystalline lens of the eye and improve accommodation on eyes who suffer from presbyopia.

  9. Autocorrelation measurement of 6-fs pulses based on the two-photon-induced photocurrent in a GaAsP photodiode

    NARCIS (Netherlands)

    Ranka, J.K.; Gaeta, A.L.; Baltuska, A.; Pshenichnikov, M.S.; Wiersma, D.A.

    1997-01-01

    We experimentally characterize the two-photon response of a GaAsP photodiode by use of a femtosecond Ti:sapphire laser tuned below the diode bandgap. The photodiode is shown to be highly suitable for real-time second-order autocorrelation measurements of pulses as short as 6 fs in duration and with

  10. The influence of ns- and fs-LA plume local conditions on the performance of a combined LIBS/LA-ICP-MS sensor

    Energy Technology Data Exchange (ETDEWEB)

    LaHaye, Nicole L.; Phillips, Mark C.; Duffin, Andrew M.; Eiden, Gregory C.; Harilal, Sivanandan S.

    2016-01-01

    Both laser-induced breakdown spectroscopy (LIBS) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) are well-established analytical techniques with their own unique advantages and disadvantages. The combination of the two analytical methods is a very promising way to overcome the challenges faced by each method individually. We made a comprehensive comparison of local plasma conditions between nanosecond (ns) and femtosecond (fs) laser ablation (LA) sources in a combined LIBS and LA-ICP-MS system. The optical emission spectra and ICP-MS signal were recorded simultaneously for both ns- and fs-LA and figures of merit of the system were analyzed. Characterization of the plasma was conducted by evaluating temperature and density of the plume under various irradiation conditions using optical emission spectroscopy, and correlations to ns- and fs-LIBS and LA-ICP-MS signal were made. The present study is very useful for providing conditions for a multimodal system as well as giving insight into how laser ablation plume parameters are related to LA-ICP-MS and LIBS results for both ns- and fs-LA.

  11. Detailed experimental results for laser acceleration staging

    Directory of Open Access Journals (Sweden)

    W. D. Kimura

    2001-10-01

    Full Text Available Detailed experimental results of staging two laser-driven, relativistic electron accelerators are presented. During the experiment called STELLA (staged electron laser acceleration, an inverse free-electron laser (IFEL is used to modulate the electron energy, thereby, causing ∼3 fs microbunches to form separated by the laser wavelength at 10.6 μm (equivalent to a 35 fs period. A second IFEL accelerates the electrons depending upon the phase of the microbunches entering the second IFEL with respect to the laser beam driving the second IFEL. The data presented includes electron energy spectra as a function of the phase delay and laser power driving the first IFEL. Also shown is a comparison with the computer model, which includes space charge and misalignment effects.

  12. Study of a Li/polymer electrolyte/V{sub 2}O{sub 5} battery; Etude d`un accumulateur Li/POE/V{sub 2}O{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Tassin, N.; Bronoel, G.; Fauvarque, J.F.; Millot, A. [Laboratoire SORAPEC, 94 - Fontenay-sous-Bois (France)

    1996-12-31

    The use of POE solid polymer electrolytes in negative lithium electrode batteries allows to reach energy density values close to 150 Wh/kg. The functioning of Li/POE/V{sub 2}O{sub 5} elements has been studied on small capacity elementary cells (about 26 mAh) and the results obtained were confirmed using coiled elements of 1.4 to 1.8 Ah capacity. This work has been carried out for Bollore Technologies (BT) and Electricite de France (EdF) companies. (J.S.)

  13. EST Table: FS906357 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS906357 E_FL_fufe_07P06_F_0 10/09/28 89 %/170 aa gb|EFA11544.1| kurtz [Tribolium c...l|GB13683-PA 10/09/10 89 %/170 aa gi|270015096|gb|EFA11544.1| kurtz [Tribolium castaneum] FS911973 fufe ...

  14. EST Table: FS932328 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS932328 E_FL_fwgP_33O12_F_0 10/09/28 72 %/148 aa ref|NP_001166687.1| cuticular pro...mology 10/08/29 n.h 10/09/10 low homology 10/09/10 low homology 10/09/10 low homology FS934632 fwgP ...

  15. EST Table: FS832832 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS832832 E_FL_fmgV_41G24_R_0 11/12/09 GO hit GO:0003824(catalytic activity)|GO:0004...a gnl|Amel|GB18896-PA 10/09/10 39 %/281 aa gi|91091528|ref|XP_970224.1| PREDICTED: similar to beta-glucosidase [Tribolium castaneum] FS832832 fmgV ...

  16. EST Table: FS932732 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS932732 E_FL_fwgP_35B10_F_0 10/09/28 99 %/200 aa ref|NP_001091823.1| poly A bindin...75975.1| PREDICTED: similar to poly A binding protein isoform 4 [Tribolium castaneum] FS932483 fwgP ...

  17. EST Table: FS898131 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS898131 E_FL_ftes_29L01_R_0 10/09/28 43 %/185 aa ref|XP_002736928.1| PREDICTED: sorting and assembly machin...341|ref|XP_966817.2| PREDICTED: similar to sorting and assembly machinery component 50 homolog [Tribolium castaneum] FS871738 ftes ...

  18. EST Table: FS917025 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS917025 E_FL_fufe_40B06_F_0 11/12/09 GO hit GO:0016020(membrane) 10/09/28 94 %/274.../09/10 82 %/271 aa gi|91082327|ref|XP_974606.1| PREDICTED: similar to prohibitin protein WPH [Tribolium castaneum] FS917025 fufe ...

  19. EST Table: FS922014 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS922014 E_FL_fwgP_03G10_F_0 11/12/09 n.h 10/09/28 43 %/123 aa ref|XP_001650999.1| ...A 10/09/10 41 %/128 aa gi|91089477|ref|XP_969208.1| PREDICTED: similar to AGAP011858-PA [Tribolium castaneum] FS922014 fwgP ...

  20. EST Table: FS767215 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS767215 E_FL_fcaL_45F03_F_0 10/09/28 44 %/190 aa ref|XP_975194.1| PREDICTED: similar to something...ref|XP_975194.1| PREDICTED: similar to something about silencing protein 10 [Tribolium castaneum] FS937283 fcaL ...

  1. EST Table: FS913032 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS913032 E_FL_fufe_28A02_F_0 10/09/28 44 %/216 aa ref|XP_975194.1| PREDICTED: similar to something...A 10/09/10 44 %/216 aa gi|91081571|ref|XP_975194.1| PREDICTED: similar to something about silencing protein 10 [Tribolium castaneum] FS937283 fufe ...

  2. EST Table: FS920530 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS920530 E_FL_fufe_50K23_F_0 11/12/09 GO hit GO:0047800(cysteamine dioxygenase acti...090992|ref|XP_974899.1| PREDICTED: similar to 2-aminoethanethiol (cysteamine) dioxygenase [Tribolium castaneum] FS920530 fufe ...

  3. EST Table: FS845801 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS845801 E_FL_fner_24L14_F_0 10/09/28 43 %/155 aa ref|XP_971046.2| PREDICTED: similar to antolefin... %/116 aa gnl|Amel|GB16043-PA 10/09/10 43 %/155 aa gi|189240340|ref|XP_971046.2| PREDICTED: similar to antolefinin [Tribolium castaneum] FS921551 fner ...

  4. EST Table: FS848732 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS848732 E_FL_fner_33A19_F_0 10/09/28 39 %/198 aa ref|XP_971046.2| PREDICTED: similar to antolefin... %/152 aa gnl|Amel|GB16043-PA 10/09/10 39 %/198 aa gi|189240340|ref|XP_971046.2| PREDICTED: similar to antolefinin [Tribolium castaneum] FS921551 fner ...

  5. EST Table: FS918193 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS918193 E_FL_fufe_43J18_F_0 10/09/28 39 %/198 aa ref|XP_971046.2| PREDICTED: similar to antolefin... %/152 aa gnl|Amel|GB16043-PA 10/09/10 39 %/198 aa gi|189240340|ref|XP_971046.2| PREDICTED: similar to antolefinin [Tribolium castaneum] FS921551 fufe ...

  6. EST Table: FS905568 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS905568 E_FL_fufe_05H13_F_0 10/09/28 40 %/188 aa ref|XP_971046.2| PREDICTED: similar to antolefin... %/142 aa gnl|Amel|GB16043-PA 10/09/10 40 %/188 aa gi|189240340|ref|XP_971046.2| PREDICTED: similar to antolefinin [Tribolium castaneum] FS921551 fufe ...

  7. EST Table: FS867121 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS867121 E_FL_fner_33A19_R_0 10/09/28 39 %/198 aa ref|XP_971046.2| PREDICTED: similar to antolefin... %/152 aa gnl|Amel|GB16043-PA 10/09/10 39 %/198 aa gi|189240340|ref|XP_971046.2| PREDICTED: similar to antolefinin [Tribolium castaneum] FS752084 fner ...

  8. EST Table: FS882512 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS882512 E_FL_ftes_24I11_F_0 10/09/28 46 %/122 aa ref|XP_968918.2| PREDICTED: similar to william...189241014|ref|XP_968918.2| PREDICTED: similar to williams-beuren syndrome critical region protein [Tribolium castaneum] FS920403 ftes ...

  9. EST Table: FS905741 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS905741 E_FL_fufe_06A07_F_0 10/09/28 31 %/238 aa ref|XP_968918.2| PREDICTED: similar to william...189241014|ref|XP_968918.2| PREDICTED: similar to williams-beuren syndrome critical region protein [Tribolium castaneum] FS920403 fufe ...

  10. EST Table: FS920155 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS920155 E_FL_fufe_49I16_F_0 11/12/09 GO hit GO:0004175(endopeptidase activity)|GO:...|Amel|GB10411-PA 10/09/10 87 %/232 aa gi|189237685|ref|XP_969117.2| PREDICTED: similar to proteasome beta-subunit [Tribolium castaneum] FS920155 fufe ...

  11. EST Table: FS912016 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS912016 E_FL_fufe_25A02_F_0 11/12/09 GO hit GO:0016787(hydrolase activity) 10/09/2...5 %/292 aa gi|91078974|ref|XP_974434.1| PREDICTED: similar to CG8889 CG8889-PA [Tribolium castaneum] FS912016 fufe ...

  12. EST Table: FS843095 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS843095 E_FL_fner_17B02_F_0 10/09/28 84 %/185 aa ref|XP_972038.2| PREDICTED: similar to liquid facets...26|ref|XP_972038.2| PREDICTED: similar to liquid facets [Tribolium castaneum] FS840960 fner ...

  13. EST Table: FS784619 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS784619 E_FL_fcaL_48C03_R_0 10/09/28 64 %/109 aa ref|XP_970998.1| PREDICTED: similar to Evolution...187|ref|XP_970998.1| PREDICTED: similar to Evolutionarily conserved signaling intermediate in Toll pathway, mitochondrial [Tribolium castaneum] FS874188 fcaL ...

  14. EST Table: FS877412 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS877412 E_FL_ftes_09L06_F_0 10/09/28 63 %/108 aa ref|XP_970998.1| PREDICTED: similar to Evolution...94187|ref|XP_970998.1| PREDICTED: similar to Evolutionarily conserved signaling intermediate in Toll pathway, mitochondrial [Tribolium castaneum] FS756091 ftes ...

  15. EST Table: FS773307 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS773307 E_FL_fcaL_01B18_R_0 10/09/28 51 %/210 aa ref|XP_970998.1| PREDICTED: similar to Evolution...187|ref|XP_970998.1| PREDICTED: similar to Evolutionarily conserved signaling intermediate in Toll pathway, mitochondrial [Tribolium castaneum] FS874188 fcaL ...

  16. EST Table: FS855034 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS855034 E_FL_fner_50N16_F_0 10/09/28 56 %/216 aa ref|XP_391845.2| PREDICTED: similar to tout...44.1| PREDICTED: similar to tout-velu CG10117-PA [Tribolium castaneum] FS931854 fner ...

  17. EST Table: FS911854 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS911854 E_FL_fufe_24H22_F_0 10/09/28 57 %/294 aa ref|XP_391845.2| PREDICTED: similar to tout...44.1| PREDICTED: similar to tout-velu CG10117-PA [Tribolium castaneum] FS931854 fufe ...

  18. EST Table: FS938466 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS938466 E_FL_fwgP_52B08_F_0 10/09/28 57 %/272 aa ref|XP_391845.2| PREDICTED: similar to tout...44.1| PREDICTED: similar to tout-velu CG10117-PA [Tribolium castaneum] FS931854 fwgP ...

  19. EST Table: FS917270 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS917270 E_FL_fufe_40N17_F_0 10/09/28 58 %/313 aa ref|XP_391845.2| PREDICTED: similar to tout...44.1| PREDICTED: similar to tout-velu CG10117-PA [Tribolium castaneum] FS931854 fufe ...

  20. EST Table: FS923093 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS923093 E_FL_fwgP_06I17_F_0 10/09/28 56 %/267 aa ref|XP_391845.2| PREDICTED: similar to tout...44.1| PREDICTED: similar to tout-velu CG10117-PA [Tribolium castaneum] FS931854 fwgP ...

  1. EST Table: FS807950 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS807950 E_FL_fmgV_24P14_F_0 10/09/28 54 %/237 aa ref|XP_391845.2| PREDICTED: similar to tout...44.1| PREDICTED: similar to tout-velu CG10117-PA [Tribolium castaneum] FS931854 fmgV ...

  2. EST Table: FS806566 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS806566 E_FL_fmgV_21B09_F_0 10/09/28 55 %/236 aa ref|XP_391845.2| PREDICTED: similar to tout...44.1| PREDICTED: similar to tout-velu CG10117-PA [Tribolium castaneum] FS931854 fmgV ...

  3. EST Table: FS905383 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS905383 E_FL_fufe_04O05_F_0 10/09/28 54 %/244 aa ref|XP_391845.2| PREDICTED: similar to tout...44.1| PREDICTED: similar to tout-velu CG10117-PA [Tribolium castaneum] FS931854 fufe ...

  4. EST Table: FS764450 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS764450 E_FL_fcaL_36N15_F_0 10/09/28 42 %/214 aa ref|XP_001945612.1| PREDICTED: similar to glucocerebro...608.1| PREDICTED: similar to putative lysosomal glucocerebrosidase [Tribolium castaneum] FS759318 fcaL ...

  5. EST Table: FS919981 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS919981 E_FL_fufe_49A03_F_0 11/12/09 n.h 10/09/28 41 %/110 aa gb|EFA11746.1| hypot...41 %/110 aa gi|270015298|gb|EFA11746.1| hypothetical protein TcasGA2_TC004236 [Tribolium castaneum] FS919981 fufe ...

  6. EST Table: FS844425 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS844425 E_FL_fner_20L21_F_0 10/09/28 67 %/134 aa ref|XP_974541.1| PREDICTED: similar to Media...74541.1| PREDICTED: similar to Mediator complex subunit 11 CG6884-PA [Tribolium castaneum] FS919479 fner ...

  7. EST Table: FS937741 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS937741 E_FL_fwgP_49P08_F_0 10/09/28 67 %/132 aa ref|XP_974541.1| PREDICTED: similar to Media...74541.1| PREDICTED: similar to Mediator complex subunit 11 CG6884-PA [Tribolium castaneum] FS919479 fwgP ...

  8. EST Table: FS836036 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS836036 E_FL_fmgV_50E03_R_0 11/12/09 GO hit GO:0005515(protein binding)|GO:0008745...CTED: similar to Tm-peptidoglycan recogntition protein-SA [Tribolium castaneum] FS836036 fmgV ...

  9. EST Table: FS836368 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS836368 E_FL_fmgV_51D01_R_0 10/09/28 90 %/196 aa dbj|BAG41976.1| alkaline phosphat... 47 %/164 aa gi|270012502|gb|EFA08950.1| hypothetical protein TcasGA2_TC006657 [Tribolium castaneum] FS823697 fmgV ...

  10. EST Table: FS930966 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS930966 E_FL_fwgP_29M10_F_0 10/09/28 44 %/215 aa ref|XP_969763.1| PREDICTED: similar to meteor...a gi|91078226|ref|XP_969763.1| PREDICTED: similar to meteorin [Tribolium castaneum] FS767139 fwgP ...

  11. EST Table: FS767139 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS767139 E_FL_fcaL_45B09_F_0 11/12/09 n.h 10/09/28 43 %/171 aa ref|XP_969763.1| PREDICTED: similar to meteor...10 43 %/171 aa gi|91078226|ref|XP_969763.1| PREDICTED: similar to meteorin [Tribolium castaneum] FS767139 fcaL ...

  12. EST Table: FS849851 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS849851 E_FL_fner_36C21_F_0 10/09/28 44 %/171 aa ref|XP_969763.1| PREDICTED: similar to meteor...a gi|91078226|ref|XP_969763.1| PREDICTED: similar to meteorin [Tribolium castaneum] FS767139 fner ...

  13. EST Table: FS845415 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS845415 E_FL_fner_23J15_F_0 10/09/28 42 %/122 aa ref|XP_969763.1| PREDICTED: similar to meteor...a gi|91078226|ref|XP_969763.1| PREDICTED: similar to meteorin [Tribolium castaneum] FS767139 fner ...

  14. EST Table: FS855797 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS855797 E_FL_fner_52P17_F_0 10/09/28 43 %/137 aa ref|XP_969763.1| PREDICTED: similar to meteor...a gi|91078226|ref|XP_969763.1| PREDICTED: similar to meteorin [Tribolium castaneum] FS767139 fner ...

  15. EST Table: FS850158 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS850158 E_FL_fner_37A23_F_0 10/09/28 43 %/137 aa ref|XP_969763.1| PREDICTED: similar to meteor...a gi|91078226|ref|XP_969763.1| PREDICTED: similar to meteorin [Tribolium castaneum] FS767139 fner ...

  16. EST Table: FS854689 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS854689 E_FL_fner_49N22_F_0 10/09/28 67 %/202 aa ref|XP_395977.1| PREDICTED: similar to mRNA dec..._968428.1| PREDICTED: similar to Decapping protein 2 CG6169-PA [Tribolium castaneum] FS769359 fner ...

  17. EST Table: FS772264 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS772264 E_FL_fcaL_24O15_F_0 10/09/28 69 %/158 aa ref|XP_395977.1| PREDICTED: similar to mRNA dec..._968428.1| PREDICTED: similar to Decapping protein 2 CG6169-PA [Tribolium castaneum] FS769359 fcaL ...

  18. EST Table: FS758250 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS758250 E_FL_fcaL_07L19_F_0 10/09/28 69 %/226 aa ref|XP_395977.1| PREDICTED: similar to mRNA dec..._968428.1| PREDICTED: similar to Decapping protein 2 CG6169-PA [Tribolium castaneum] FS769359 fcaL ...

  19. Lead nitroprusside: A new precursor for the synthesis of the multiferroic Pb{sub 2}Fe{sub 2}O{sub 5,} an anion-deficient perovskite

    Energy Technology Data Exchange (ETDEWEB)

    Gil, Diego M. [Instituto de Química Inorgánica, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471, 4000 San Miguel de Tucumán (Argentina); Nieva, Gladys [Centro Atómico Bariloche, Instituto Balseiro, Comisión Nacional de Energía Atómica, Universidad Nacional de Cuyo, 8400 San Carlos de Bariloche (Argentina); Franco, Diego G. [Centro Atómico Bariloche, Instituto Balseiro, Comisión Nacional de Energía Atómica, Universidad Nacional de Cuyo, 8400 San Carlos de Bariloche (Argentina); Instituto de Investigaciones en Fisicoquímica de Córdoba (INFIQC – CONICET), Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba (Argentina); Gómez, María Inés [Instituto de Química Inorgánica, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471, 4000 San Miguel de Tucumán (Argentina); and others

    2013-08-15

    In order to investigate the formation of multiferroic oxide Pb{sub 2}Fe{sub 2}O{sub 5}, the thermal decomposition of Pb[Fe(CN){sub 5}NO] has been studied. The complex precursor and the thermal decomposition products were characterized by IR and Raman spectroscopy, thermal analysis, powder X-ray diffraction (PXRD), scanning electron microscopy and magnetic measurements. The crystal structure of Pb[Fe(CN){sub 5}NO] was refined by Rietveld analysis. It crystallizes in the orthorhombic system, space group Pnma. The thermal decomposition in air produces highly pure Pb{sub 2}Fe{sub 2}O{sub 5} as final product. This oxide is an anion deficient perovskite with an incommensurate superstructure. The magnetic measurements confirm that Pb{sub 2}Fe{sub 2}O{sub 5} shows a weak ferromagnetic signal probably due to disorder in the perfect antiferromagnetic structure or spin canting. The estimated ordering temperature from the fit of a phenomenological model was 520 K. The SEM images reveal that the thermal decomposition of Pb[Fe(CN){sub 5}NO] produces Pb{sub 2}Fe{sub 2}O{sub 5} with small particle size. - Highlights: • Pb[Fe(CN){sub 5}NO] was synthesized and characterized. • Pb[Fe(CN){sub 5}NO] belongs to orthorhombic crystal system, space group Pnma. • Pb{sub 2}Fe{sub 2}O{sub 5} was obtained by thermal decomposition of Pb[Fe(CN){sub 5}NO]. • Pb{sub 2}Fe{sub 2}O{sub 5} is a weak ferromagnet due to spin canting. • Ordering temperature of Pb{sub 2}Fe{sub 2}O{sub 5} from the fit of a phenomenological model was 520 K. - Graphical abstract: Field cooling (FC) and zero field cooling (ZFC) magnetization curves at H = 10 and 1000 Oe for Pb{sub 2}Fe{sub 2}O{sub 5} obtained at 750 °C. Remnant magnetization after applying H = 1 T, FC procedure at 0.8 Oe. The fitted expression (see text) yield an ordering temperature T{sub o} = 520 K. Display Omitted.

  20. An investigation on 800 nm femtosecond laser ablation of K9 glass in air and vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Shi-zhen, E-mail: xusz@uestc.edu.cn [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Yao, Cai-zhen [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Dou, Hong-qiang [Department of Material Science and Engineering, Sichuan Engineering Technical College, Deyang 618000 (China); Liao, Wei, E-mail: liaowei@caep.cn [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Li, Xiao-yang; Ding, Ren-jie [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Zhang, Li-juan; Liu, Hao; Yuan, Xiao-dong [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Zu, Xiao-tao [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2017-06-01

    Highlights: • The fs laser ablation of borosilicate glass (K9) were investigated under 35 and 500 fs pulses. • At high fluence regime, the ablation rate at 35 fs in air increased to a plateau, and 500 fs in air and vacuum decreased. • The mechanisms of multiple-photon ionization and impact ionization were included. • The ablation morphologies of smooth zone and laser-induced periodic surface structures were presented and illustrated. • The ablation mechanisms of non-thermal and thermal ablation were included. - Abstract: Ablation rates of K9 glass were studied as a function of femtosecond laser fluences. The central wavelength was 800 nm, and pulse durations of 35 fs and 500 fs in air and vacuum were employed. Ablation thresholds of 0.42 J/cm{sup 2} and 2.1 J/cm{sup 2} were obtained at 35 fs and 500 fs, respectively, which were independent with the ambient conditions and depend on the incident pulse numbers due to incubation effects. The ablation rate of 35 fs pulse laser increased with the increasing of laser fluence in vacuum, while in air condition, it slowly increased to a plateau at high fluence. The ablation rate of 500 fs pulse laser showed an increase at low fluence and a slow drop of ablation rate was observed at high fluence in air and vacuum, which may due to the strong defocusing effects associated with the non-equilibrium ionization of air, and/or the shielding effects of conduction band electrons (CBEs) produced by multi-photon ionization and impact ionization in K9 glass surface. The typical ablation morphologies, e.g. smooth zone and laser-induced periodic surface structures (LIPSS) were also presented and illustrated.

  1. Central corneal sensitivity after small incision lenticule extraction versus femtosecond laser-assisted LASIK for myopia: a meta-analysis of comparative studies

    National Research Council Canada - National Science Library

    He, Miao; Huang, Wenyong; Zhong, Xingwu

    2015-01-01

    ...) versus femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for myopia. Eligible studies were identified by systematically searching PubMed, the Cochrane Library, Embase and the Chinese Biomedicine Database...

  2. Transverse mode-locking in microcavity lasers

    Science.gov (United States)

    Gordon, R.; Heberle, A. P.; Cleaver, J. R. A.

    2002-12-01

    We experimentally demonstrate mode-locking between the transverse modes of a laser. A vertical-cavity surface-emitting laser with evenly-spaced transverse modes is shown to emit a train of 2.1±0.1 ps pulses with an 11 ps repetition rate and a timing jitter of 235±30 fs. Transverse mode-locking in microcavity lasers has potential to improve the compactness, stability, integrability, repetition rate tunability, and efficiency of ultrafast optical communication sources.

  3. MarFS-Requirements-Design-Configuration-Admin

    Energy Technology Data Exchange (ETDEWEB)

    Kettering, Brett Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Grider, Gary Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-08

    This document will be organized into sections that are defined by the requirements for a file system that presents a near-POSIX (Portable Operating System Interface) interface to the user, but whose data is stored in whatever form is most efficient for the type of data being stored. After defining the requirement the design for meeting the requirement will be explained. Finally there will be sections on configuring and administering this file system. More and more, data dominates the computing world. There is a “sea” of data out there in many different formats that needs to be managed and used. “Mar” means “sea” in Spanish. Thus, this product is dubbed MarFS, a file system for a sea of data.

  4. Rationalizing long-lived photo-excited carriers in photocatalyst (La{sub 5}Ti{sub 2}CuS{sub 5}O{sub 7}) in terms of one-dimensional carrier transport

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Yohichi; Singh, Rupashree Balia; Matsuzaki, Hiroyuki [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Furube, Akihiro [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Institute of Technology and Science, Tokushima University, 2-1, Minamijosanjima-cho, Tokushima 770-8506 (Japan); Ma, Guijun; Hisatomi, Takashi; Domen, Kazunari [Department of Chemical System Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem), 2-11-9 Iwamotocho, Chiyoda-ku, Tokyo 101-0032 (Japan); Seki, Kazuhiko, E-mail: k-seki@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan)

    2016-09-12

    The semiconductor La{sub 5}Ti{sub 2}CuS{sub 5}O{sub 7} (LTC) is a potential photocatalyst capable of operating under visible light irradiation and behaves both as a photocathode and anode when embedded onto metal layers. Time-resolved diffuse reflectance (TRDR) measurements were carried out on LTC powder and LTC deposited on Au as the back contact using the particle-transfer method. Results of TRDR measurements of powdered LTC indicated the existence of long-lived photo-excited carriers, and suggested the existence of a mechanism for preventing carrier loss in LTC. Prior research has reported that LTC has a rod-shaped crystal structure and that electrons and holes are transported through different, spatially separated channels. Based on this, we introduced a one-dimensional carrier transport model. By analyzing TRDR data, we extracted material parameters such as the diffusion coefficient of LTC. Theoretical results indicated that a micron-sized LTC particle would be preferable if carriers trapped at the top-surface do contribute to photocatalytic gas generation.

  5. Transport properties of Ru-doped La sub 1 sub . sub 8 sub 5 Sr sub 0 sub . sub 1 sub 5 CuO sub 4 and the effect of carrier concentration compensation

    CERN Document Server

    Xiong, Y M; Luo, X G; Zhang, H T; Wang, C H; Li, S Y; Chen, X H

    2003-01-01

    This paper is a study of the structure and transport properties of Ru-doped La sub 1 sub . sub 8 sub 5 Sr sub 0 sub . sub 1 sub 5 CuO sub 4. It is found that Ru substitution for Cu has two effects. (1) Ru doping introduces disorder into the system, which causes a metal-insulator transition with high localization. (2) There is a hole-filling effect due to the valence of the Ru ion being higher than that of the Cu ion. Increase of the strontium content could compensate for the imbalance of valence caused by doping with the high-valence Ru ion. A universal curve for T sub c versus the number of holes per Cu site is observed for the La sub 2 sub - sub y Sr sub y Cu sub 1 sub - sub x Ru sub x O sub 4 system, indicating that a rigid-band model holds and T sub c correlates with features in the density of states, such as a Van Hove singularity.

  6. Studies of the structural and electrical properties of lithium ferrite (LiFe{sub 5}O{sub 8})

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, R S T M; Sombra, A S B [Department of Physics, Federal University of Ceara Campus do Pici, Postal Code 6030, 60455-760, Fortaleza, CE (Brazil); Macedo, A A M; Mazzetto, S E [Technology Products Laboratory (LPT), Northeast Network on Biotechnology (RENORBIO), Federal University of Ceara, Postal Code 6021, 60455-900, Fortaleza, CE (Brazil); Costa, M M, E-mail: www.locem@ufc.b [Telecommunications and Materials Science and Engineering Laboratory (LOCEM), Department of Physics, Federal University of Ceara Campus do Pici, Postal Code 6030, 60455-760, Fortaleza, CE (Brazil)

    2010-11-15

    A lithium ferrite with the general formula LiFe{sub 5}O{sub 8} was prepared by a new variation of the ceramic method, in which high-energy mechanical milling and calcinations of Li{sub 2}CO{sub 3} and Fe{sub 2}O{sub 3} were used. In this paper, we present a study of the structural and electrical properties of this ceramic phase. We also investigate the effects of the use of galactomannan as a new binding option as compared with a traditional binding material like glycerol.

  7. Finite-size giant magnons on η-deformed AdS{sub 5}×S{sup 5}

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Changrim, E-mail: ahn@ewha.ac.kr; Bozhilov, Plamen, E-mail: bozhilov@inrne.bas.bg

    2014-10-07

    We consider strings moving in the R{sub t}×S{sub η}{sup 3} subspace of the η-deformed AdS{sub 5}×S{sup 5} and obtain a class of solutions depending on several parameters. They are characterized by the string energy and two angular momenta. Finite-size dyonic giant magnon belongs to this class of solutions. Further on, we restrict ourselves to the case of giant magnon with one nonzero angular momentum, and obtain the leading finite-size correction to the dispersion relation.

  8. Spectrum and quantum symmetries of the AdS{sub 5} x S{sup 5} superstring

    Energy Technology Data Exchange (ETDEWEB)

    Heinze, Martin

    2014-12-18

    The initial AdS/CFT duality pair, the duality between N=4 SYM and the AdS{sub 5} x S{sup 5} superstring, appears to enjoy quantum integrability in the planar limit, which allowed to devise powerful methods ostensibly solving the spectral problem. However, quantization of the AdS{sub 5} x S{sup 5} superstring from first principles is still an open question and especially the spectrum of short string states has previously been derived only at leading order in large 't Hooft coupling. In this thesis we investigate possible routes to quantize short string states perturbatively beyond the leading order, where equally our aim is to gain better appreciation of the quantum symmetries at play. A prominent role is played by the lowest excited string states, dual to the Konishi supermultiplet, and we start by reviewing critically an asserted derivation of the Konishi anomalous dimension in the setup of pure spinor string theory. Next, we constrain ourselves to bosonic AdS{sub 5} x S{sup 5} String in static gauge, where we construct a so-called single-mode string solution, a generalization of the pulsating string allowing for unconstrained zero-modes. This solution shows classical integrability and invariance under the isometries SO(2,4) x SO(6) at the quantum level. Arguing heuristically about the effects of supersymmetry, we indeed recover the first non-trivial quantum correction to the Konishi anomalous dimension. We continue by implementing static gauge for the full AdS{sub 5} x S{sup 5} superstring and find elegant expressions for the Lagrangian density and the supercharges. We then constrain our interest to the superparticle and, using two different methods, find canonical coordinates at quadratic order in fermions. We conclude by exploring another quantization scheme: As the single-mode string is nothing but the SO(2,4) x SO(6) orbit of the pulsating string, we apply orbit method quantization to the particle and spinning string solutions in bosonic AdS{sub 3} x S

  9. Mechanochemically synthesized sub-5 nm sized CuS quantum dots with high visible-light-driven photocatalytic activity

    Science.gov (United States)

    Li, Shun; Ge, Zhen-Hua; Zhang, Bo-Ping; Yao, Yao; Wang, Huan-Chun; Yang, Jing; Li, Yan; Gao, Chao; Lin, Yuan-Hua

    2016-10-01

    We report a simple mechanochemical ball milling method for synthesizing monodisperse CuS quantum dots (QDs) with sizes as small as sub-5 nm. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV-vis spectroscopy. The CuS QDs exhibited excellent visible-light-driven photocatalytic activity and stability for degradation of Rodanmine B aqueous solution as Fenton-like reagents. Our study opens the opportunity to low-cost and facile synthesis of QDs in large scale for future industrial applications.

  10. Effect of Th substitution on ferrimagnetic transition in the heavy-electron compound UCu{sub 5}Sn

    Energy Technology Data Exchange (ETDEWEB)

    Troc, Robert E-mail: troc@int.pan.wroc.pl; Tran, Vinh Hung; Andraka, Bohdan; Pietri, Robert; Cichorek, Tomasz

    2001-05-01

    It was found that the ferrimagnetic properties of the solid solutions (U{sub 1-x} Th{sub x})Cu{sub 5}Sn are detected almost up to x congruent with 0.8. Non-Fermi liquid-like behavior with unusual log T dependences of C/T has been observed for all the alloys studied, i.e. not only in nonmagnetic but also in magnetically ordered states. A possible interpretation of these data based on the recent development of unconventional Kondo models is given.

  11. The relationship between discharge capacity of LaNi{sub 5} type hydrogen storage alloys and formation enthalpy

    Energy Technology Data Exchange (ETDEWEB)

    Ma Xiaobo; Wei Xuedong; Dong Hui [State Key Laboratory of Mechanical Behavior of Materials, School of Material Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Liu Yongning, E-mail: ynliu@mail.xjtu.edu.c [State Key Laboratory of Mechanical Behavior of Materials, School of Material Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2010-02-04

    The formation enthalpy of LaNi{sub 5} type hydrogen storage alloys has been calculated using a semi-empirical formula that takes into account the electronegativities, the atomic size, and the electron concentration of each constituent element in the alloys. Through our calculations, it was found that the formation enthalpy of the alloys is directly related to the discharge capacities of the alloys. When the absolute value of formation enthalpy decreases, the discharge capacity increases. The result provides a valuable reference for alloy design.

  12. Integrable λ-deformations: squashing coset CFTs and AdS{sub 5}×S{sup 5}

    Energy Technology Data Exchange (ETDEWEB)

    Demulder, Saskia [Theoretische Natuurkunde, Vrije Universiteit Brussel andThe International Solvay Institutes,Pleinlaan 2, B-1050, Brussels (Belgium); Sfetsos, Konstantinos [Department of Nuclear and Particle Physics, Faculty of Physics, University of Athens,Athens 15784 (Greece); Thompson, Daniel C. [Theoretische Natuurkunde, Vrije Universiteit Brussel andThe International Solvay Institutes,Pleinlaan 2, B-1050, Brussels (Belgium)

    2015-07-06

    We examine integrable λ-deformations of SO(n+1)/SO(n) coset CFTs and their analytic continuations. We provide an interpretation of the deformation as a squashing of the corresponding coset σ-model’s target space. We realise the λ-deformation for n=5 case as a solution to supergravity supported by non-vanishing five-form and dilaton. This interpolates between the coset CFT SO(4,2)/SO(4,1)×SO(6)/SO(5) constructed as a gauged WZW model and the non-Abelian T-dual of the AdS{sub 5}×S{sup 5} spacetime.

  13. Application of ultrashort laser pulses for intrastromal refractive surgery.

    Science.gov (United States)

    Lubatschowski, H; Maatz, G; Heisterkamp, A; Hetzel, U; Drommer, W; Welling, H; Ertmer, W

    2000-01-01

    Recently, laser systems have become available which generate ultrashort laser pulses with a duration of 100-200 femtoseconds (fs). By generating micro-plasmas inside the corneal stroma with fs pulses, it is possible to achieve a cutting effect inside the tissue while leaving the anterior layers intact. The energy threshold to generate a micro-plasma with fs pulses is some orders of magnitude lower than it is for picosecond or nanosecond pulses. This results in a strong reduction of the thermal and mechanical damage of the surrounding tissue. With a titanium:sapphire fs laser system, the cutting effect on corneal tissue from freshly enucleated porcine eye globes was investigated with different pulse energies. The irradiated samples were examined by light and electron microscopy. The laser-induced pressure transients and the laser-induced bubble formation were analysed with a broadband acoustic transducer and by flash photography. With fs laser pulses, the extent of thermal and mechanical damage of the adjacent tissue is in the order of 1 microm or below and therefore comparable with the tissue alterations after ArF excimer laser ablation. Using pulse energies of approximately 1-2 microJ and a spot diameter of 5-10 microm, intrastromal cuts can be performed very precisely in order to prepare corneal flaps and lenticules. Femtosecond photodisruption has the potential to become an attractive tool for intrastromal refractive surgery.

  14. Factors Influencing Intraocular Pressure Changes after Laser In Situ Keratomileusis with Flaps Created by Femtosecond Laser or Mechanical Microkeratome.

    Directory of Open Access Journals (Sweden)

    Meng-Yin Lin

    Full Text Available The aim of this study is to describe factors that influence the measured intraocular pressure (IOP change and to develop a predictive model after myopic laser in situ keratomileusis (LASIK with a femtosecond (FS laser or a microkeratome (MK. We retrospectively reviewed preoperative, intraoperative, and 12-month postoperative medical records in 2485 eyes of 1309 patients who underwent LASIK with an FS laser or an MK for myopia and myopic astigmatism. Data were extracted, such as preoperative age, sex, IOP, manifest spherical equivalent (MSE, central corneal keratometry (CCK, central corneal thickness (CCT, and intended flap thickness and postoperative IOP (postIOP at 1, 6 and 12 months. Linear mixed model (LMM and multivariate linear regression (MLR method were used for data analysis. In both models, the preoperative CCT and ablation depth had significant effects on predicting IOP changes in the FS and MK groups. The intended flap thickness was a significant predictor only in the FS laser group (P < .0001 in both models. In the FS group, LMM and MLR could respectively explain 47.00% and 18.91% of the variation of postoperative IOP underestimation (R2 = 0.47 and R(2 = 0.1891. In the MK group, LMM and MLR could explain 37.79% and 19.13% of the variation of IOP underestimation (R(2 = 0.3779 and 0.1913 respectively. The best-fit model for prediction of IOP changes was the LMM in LASIK with an FS laser.

  15. A determination of the oxygen non-stoichiometry of the oxygen storage material YBaMn{sub 2}O{sub 5+δ}

    Energy Technology Data Exchange (ETDEWEB)

    Jeamjumnunja, Kannika; Gong, Wenquan; Makarenko, Tatyana; Jacobson, Allan J., E-mail: ajjacob@uh.edu

    2015-10-15

    The A-site ordered double-perovskite oxide, YBaMn{sub 2}O{sub 5+δ}, has been of recent interest for possible application as an oxygen storage material. In the present study, the oxygen non-stoichiometry of YBaMn{sub 2}O{sub 5+δ} has been determined as a function of pO{sub 2} at 650, 700 and 750 °C by Coulometric titration at near-equilibrium conditions. The results confirm that this perovskite oxide has three distinct phases on oxidation/reduction with δ≈0, 0.5 and 1. The stabilities of the YBaMn{sub 2}O{sub 5+δ} phases span a wide range of oxygen partial pressures (∼10{sup −20}≤pO{sub 2}(atm)≤∼1 ) depending on temperature. The phases interconvert at higher pO{sub 2} values at higher temperatures. The partial molar free energies (Δμ{sub O}) corresponding to the oxidation of YBaMn{sub 2}O{sub 5} to YBaMn{sub 2}O{sub 5.5} and of YBaMn{sub 2}O{sub 5.5} to YBaMn{sub 2}O{sub ∼6} were determined. The value of Δμ{sub O} in both oxidation steps becomes less negative with increasing temperature. At some T and pO{sub 2} conditions, YBaMn{sub 2}O{sub 5+δ} is unstable with respect to decomposition to BaMnO{sub 3−δ} and YMnO{sub 3}. This instability is anticipated from the previous studies of the synthesis of YBaMn{sub 2}O{sub 5+δ} but is more apparent in the present experiments which are necessarily slow in order to achieve equilibrium with respect to the oxygen content. - Highlights: • Determination of the oxygen non-stoichiometry of YBaMn{sub 2}O{sub 5+δ} as a function of pO{sub 2} and T. • Establishments of pO{sub 2} ranges of stability of O{sub 5} and O{sub 5.5} at 650 °C, 700 °C and 750 °C. • Discovery of the kinetic instability of YBaMn{sub 2}O{sub 5+δ} with respect to decomposition to BaMnO{sub 3}−{sub x} and YMnO{sub 3}. • Evaluation of the thermodynamics of the oxidation of YBaMnO{sub 5}.

  16. Improvement of the specific capacitance of V{sub 2}O{sub 5} nanobelts as supercapacitor electrode by tungsten doping

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jiqi [School of Chemistry, Dalian University of Technology, Dalian 116024 (China); Zhang, Yifu, E-mail: yfzhang@dlut.edu.cn [School of Chemistry, Dalian University of Technology, Dalian 116024 (China); Jing, Xuyang [College of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029 (China); Wang, Qiushi; Hu, Tao [School of Chemistry, Dalian University of Technology, Dalian 116024 (China); Xing, Na [College of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029 (China); Meng, Changgong [School of Chemistry, Dalian University of Technology, Dalian 116024 (China)

    2017-01-15

    Tungsten doped vanadium pentoxide (W-doped V{sub 2}O{sub 5}) nanobelts were successfully synthesized by a facile hydrothermal route and combination of calcination. The results revealed that W atoms were successfully doped into the crystal lattice of V{sub 2}O{sub 5} matrix, indicating that the homogeneous solid-solutions of W-doped V{sub 2}O{sub 5} nanobelts were obtained. The electrochemical properties of W-doped V{sub 2}O{sub 5} nanobelts as supercapacitor electrode were investigated by cyclic voltammetry (CV) and galvanostatic charge discharge (GCD) methods. W-doped V{sub 2}O{sub 5} nanobelts exhibit the excellent capacity and good rate capability. Their specific capacitance are 407, 381, 350, 328, 295 and 273 F g{sup −1} at the current density of 0.5, 1, 2, 5, 10 and 20 A g{sup −1}, respectively. W-doped V{sub 2}O{sub 5} nanobelts also show excellent energy densities of 246, 217, 212, 199, 178 and 165 W h kg{sup −1} at a power densities of 0.99, 1.98, 3.96, 9.90, 19.80 and 39.60 kW kg{sup −1}. The specific capacitance of W-doped V{sub 2}O{sub 5} nanobelts is much higher than the previous values of V{sub 2}O{sub 5} materials, achieving the aim of improving the specific capacitance of V{sub 2}O{sub 5} nanobelts. - Graphical abstract: The specific capacitance of V{sub 2}O{sub 5} nanobelts can be greatly improved by W doping. - Highlights: • Homogeneous solid-solutions of W-doped V{sub 2}O{sub 5} were prepared. • W-doped V{sub 2}O{sub 5} nanobelts exhibit excellent electrochemical property. • High specific capacitance of 407 F g{sup −1} at 0.5 A g{sup −1} was achieved. • Specific capacitance of V{sub 2}O{sub 5} nanobelts was improved by doping method.

  17. Reduction of the Influence of Laser Beam Directional Dithering in a Laser Triangulation Displacement Probe.

    Science.gov (United States)

    Yang, Hongwei; Tao, Wei; Zhang, Zhengqi; Zhao, Siwei; Yin, Xiaoqia; Zhao, Hui

    2017-05-15

    Directional dithering of a laser beam potentially limits the detection accuracy of a laser triangulation displacement probe. A theoretical analysis indicates that the measurement accuracy will linearly decrease as the laser dithering angle increases. To suppress laser dithering, a scheme for reduction of the influence of laser beam directional dithering in a laser triangulation displacement probe, which consists of a collimated red laser, a laser beam pointing control setup, a receiver lens, and a charge-coupled device, is proposed in this paper. The laser beam pointing control setup is inserted into the source laser beam and the measured object and can separate the source laser beam into two symmetrical laser beams. Hence, at the angle at which the source laser beam dithers, the positional averages of the two laser spots are equal and opposite. Moreover, a virtual linear function method is used to maintain a stable average of the positions of the two spots on the imaging side. Experimental results indicate that with laser beam pointing control, the estimated standard deviation of the fitting error decreases from 0.3531 mm to 0.0100 mm , the repeatability accuracy can be lowered from ±7 mm to ±5 μ m , and the nonlinear error can be reduced from ±6 % FS (full scale) to ±0.16 % FS.

  18. Experimental demonstration of 55-fs spin canting in photoexcited iron nanoarrays

    Science.gov (United States)

    Ren, Yuhang; Lai, Wei; Cevher, Zehra; Gong, Yu; Zhang, G. P.

    2017-02-01

    As magnetic storage density approaches 1TB/in2, a grand challenge is looming as how to read/write such a huge amount of data within a reasonable time. The ultrafast optical manipulation of magnetization offers a solution, but little is known about the intrinsic speed limit of quantum spin switching. Here, we report that low-energy 50-fs laser pulses can induce spin canting in Fe nanoparticles within 55 fs, breaking the previous record by at least one order of magnitude. Both linearly and circularly polarized light can be used to tilt spins. In our model, the incident laser field first excites the orbital angular momentum, and through spin-orbit coupling, the spin cants out-of-plane and results in a distinctive diamond hysteresis loop. The spin canting time decreases with spin angular momentum. This spin canting is not limited to Fe nanoparticles and is also observed in Fe/Pt and Fe3O4 nanoparticles. Our results demonstrate the potential of magnetic nanostructures as a viable magnetic medium for high density and fast-switching magnetic storage devices.

  19. Nano crystalline Bi{sub 2}(VO{sub 5}) phases in lithium bismuth borate glasses containing mixed vanadium-nickel oxides

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Arti, E-mail: artidabhur@gmail.com; Khasa, S.; Dahiya, M. S. [Department of Physics, Deenbandhu Chhotu Ram University of Science and Technology, Murthal, India-131039 (India); Agarwal, A. [Department of Applied Physics, G. J. University of Science and Technology, Hisar, India-125001 (India)

    2016-05-23

    Glass composition 7V{sub 2}O{sub 5}·23Li{sub 2}O·20Bi{sub 2}O{sub 3}·50B{sub 2}O{sub 3} and x(2NiO·V{sub 2}O{sub 5})·(30-x)Li{sub 2}O·20Bi{sub 2}O{sub 3}·50B{sub 2}O{sub 3}, x=0, 2, 5, 7 and 10, were produced by conventional melt quenching technique. The quenched amorphous glass samples were annealed at temperatures 400°C and 500°C for 6 hours. The Bi{sub 2}(VO{sub 5}) crystallite were grown in all prepared glass matrix. Tn vanadium lithium bismuth borate glass (annealed), the some phrase of V{sub 2}O{sub 5}-crystal were observed along with the nano crystalline Bi{sub 2}(VO{sub 5}) phase. The sharp peaks in FTTR spectra of all annealed compositions were also compatible with the XRD diffraction peaks of the system under investigation. Average crystalline size (D) of the Bi{sub 2}(VO{sub 5}) nano-crystallite was ~30 nm for samples annealed at 400°C and ~42 nm for samples annealed at 500°C. Lattice parameter and the lattice strain for all the samples was also calculated corresponding to the (113) plane of Bi{sub 2}(VO{sub 5}) crystallite.

  20. Influence of the SmCo{sub 5} hard magnetic phase on the magnetoresistive properties of Cu-Fe ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Larde, R [Groupe de Physique des Materiaux UMR CNRS 6634, Universite de Rouen, Avenue de l' universite BP 12, 76801 St Etienne du Rouvray cedex (France); Le Breton, J M [Groupe de Physique des Materiaux UMR CNRS 6634, Universite de Rouen, Avenue de l' universite BP 12, 76801 St Etienne du Rouvray cedex (France); Richomme, F [Groupe de Physique des Materiaux UMR CNRS 6634, Universite de Rouen, Avenue de l' universite BP 12, 76801 St Etienne du Rouvray cedex (France); Teillet, J [Groupe de Physique des Materiaux UMR CNRS 6634, Universite de Rouen, Avenue de l' universite BP 12, 76801 St Etienne du Rouvray cedex (France); Hauet, A [Groupe de Physique des Materiaux UMR CNRS 6634, Universite de Rouen, Avenue de l' universite BP 12, 76801 St Etienne du Rouvray cedex (France); Maignan, A [Laboratoire CRISMAT-UMR 6508, ISMRA, 6 boulevard du Marechal Juin, F-14050 CAEN cedex (France); Crisan, O [National Institute for Materials Physics, PO Box MG-7, 76900 Bucharest (Romania)

    2004-10-20

    The SmCo{sub 5} hard magnetic phase was added to magnetoresistive granular Cu-Fe alloys in order to investigate the influence of the presence of a hard magnetic phase on the magnetoresistive properties of a granular alloy that contains a soft magnetic phase. Cu{sub 80}(Sm{sub 0.17}Co{sub 0.83}){sub x}Fe{sub 20-x} ribbons, with x = 20,15,10,5, obtained by melt spinning, were investigated. The ribbons are composed of magnetic Fe, SmCo{sub 5}, and Co precipitates embedded in a Cu matrix. In the as-quenched state, the magnetic interactions between magnetic precipitates lead to the formation of magnetic coherent regions and the magnetoresistance effect is only observed at high field (>1 T). After annealing, the strength of interactions decreases and a magnetoresistance effect is observed at low field (<1 T). The largest magnetoresistance effect (16%) is observed at 5 K for the Cu{sub 80}(Sm{sub 0.17}Co{sub 0.83}){sub 10}Fe{sub 10} alloy annealed at 450 deg. C.

  1. Magnetic and electronic studies of Cu{sub 80}Fe{sub 5}Ni{sub 15} granular ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Omari, N., E-mail: nabila_omari@yahoo.fr [LPTA, Université Hassan II—Casablanca, Faculté des Sciences, B.P. 5366 Maârif (Morocco); Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble cedex 9 (France); Lassri, H. [LPMMAT, Université Hassan II—Casablanca, Faculté des Sciences, B.P. 5366 Maârif (Morocco); Fnidiki, A. [Groupe de Physique des Matériaux, UMR CNRS 6634, Faculté des Sciences de Rouen, Site Universitaire du Madrillet, Avenue de l' Université, BP 12, 76801 Saint-Etienne du Rouvray Cedex (France); Abid, M. [LPTA, Université Hassan II—Casablanca, Faculté des Sciences, B.P. 5366 Maârif (Morocco); Hlil, E.K. [Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble cedex 9 (France)

    2013-10-15

    Magnetic and electronic properties of granular Cu{sub 80}Fe{sub 5}Ni{sub 15} ribbons are investigated by magnetization measurements and first principle calculations. Magnetization variation versus temperature is found to obey the Bloch law, allowing us to calculate the spin wave stiffness constant D and the exchange constant A from the experimental results. The magnetic experimental results have been interpreted within the framework of random magnetic anisotropy (RMA) model. The results have shown the possibility to extend the application of RMA to the granular ribbons. Some fundamental parameters have been extracted from the approach to saturation magnetization. In addition, self-consistent ab initio calculations, based on Korringa–Kohn–Rostocker (KKR), are performed to investigate both electronic and magnetic properties. These calculations include spin polarized potential within the framework of the Coherent Potential Approximation (CPA). - Highlights: • We have studied the magnetization of the granular Cu{sub 80}Fe{sub 5}Ni{sub 15} ribbons with the spin wave theory. • The magnetic results have been interpreted within the framework of RMA model. • We find that the local anisotropy is about 5×10{sup 5} erg/cm{sup 3} at 5 K. • ab initio calculations are performed to investigate both electronic and magnetic properties.

  2. A precursor state to unconventional superconductivity in the heavy fermion superconductor CeIrIn{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Nair, Sunil; Wirth, S.; Nicklas, M.; Steglich, F. [Max-Planck-Institute for Chemical Physics of Solids, Noethnitzer Str. 40, Dresden 01187 (Germany); Sarrao, J.L.; Thompson, J.D. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Fisk, Z. [University of California, Irvine, California 92697 (United States)

    2008-07-01

    The CeMIn{sub 5} (where M: Co, Rh or Ir) family of heavy fermion systems is currently in vogue; not only for the host of novel properties they exhibit in its normal and superconducting states, but also for the rather striking resemblance many of these properties have with the cuprate high temperature superconductors. Here, we present sensitive measurements of the Hall effect and magnetoresistance in CeIrIn{sub 5}, in the temperature range 0.05 K {<=}T {<=} 2.5 K and magnetic fields up to 15 T. The magnetoresistance is used to demarcate the presence of a low temperature Kondo coherent state. Furthermore, by means of Kohler's scaling plots, the crossover from a Landau-Fermi liquid to a non-Fermi liquid regime is inferred. The functional form of the Hall resistivity is observed to be in concurrence with that expected for a compensated metal. The most striking observation pertains to the presence of a precursor state to superconductivity characterized by a change in the Hall scattering rate, in similarity to the pseudogap state in the cuprates. Moreover, the critical fields of the precursor state and the superconducting one can be scaled on to each other, implying that they could arise from the same underlying physical mechanism.

  3. Rapid catalyst-free flame synthesis of α-Nb{sub 2}O{sub 5} micro/nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Merchan-Merchan, Wilson; Farmahini Farahani, Moien, E-mail: wmerchan-merchan@ou.edu

    2013-07-15

    We report the ultra-rapid synthesis of Nb oxide nano/micron sized rods using a flame method; the single-step process is achieved in less than a few minutes. The synthesis is performed using 1-mm diameter Nb probes (metal source) inserted in the oxygen-rich part of an counter-flow methane/acetylene oxy-flame. The niobium oxide structures can grow nearly instantaneously in a white layer of material surrounding the surface of the Nb probe. The Nb oxide layer is composed of individual and coalesced micro/nanorods that are rapidly formed on the surface of the Nb wire. The grown crystals forming the metal oxide layer grow through a basal growth mechanism due to the constant flow of oxygen and oxygen radicals from the flame onto the surface of the niobium probe. The morphology of the grown Nb oxide structures strongly depends on the flame position (temperature and chemical species). X-Ray Diffraction analysis reveals that the micro/nanorods forming the layer are composed of monoclinic α-Nb{sub 2}O{sub 5}. - Graphical abstract: Display Omitted - Highlights: • Niobium oxide crystals were grown on the surface of Nb probes using the flame method. • We report the flame as an ultra-rapid process for the growth of Nb oxide structures. • In the flame method the growth of Nb{sub 2}O{sub 5} structures is achieved in only a few minutes.

  4. Crystal and electronic structure of Y{sub 5}Al{sub 3}C{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Kotyrba, Martin R.; Nesper, Reinhard [Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zurich (Switzerland); Cuervo-Reyes, Eduardo [Reliability Science and Technology, EMPA Duebendorf, Ueberlandstrasse 129, 8600 Duebendorf (Switzerland)

    2015-07-15

    The novel ternary aluminum carbide Y{sub 5}Al{sub 3}C{sub 4} was synthesized using lithium metal as flux at high temperature (1523 K). Single-crystal structure determination of the title compound revealed a new structure type with the Wyckoff-sequence jhg2da. Y{sub 5}Al{sub 3}C{sub 4} crystallizes in the tetragonal space group P4/mbm (no. 127) with Z = 2 and lattice parameters a = 10.8442(11) and c = 3.5234(4) Aa. The compound has metallic appearance and shows remarkable structural features at the border between intermetallics and Zintl phases. The electronic band structure and the electron localization function (ELF) were calculated, both of which support the view of the infinite {sup 1}{sub ∞}[C-(Al-C)-]{sup 6-} chain as a Zintl-type anion containing aluminum and carbon. Surface cuts of the ELF also disclose intermetallic features such as yttrium-assisted Al-Al (or multicenter) bonds in the aluminum substructure. Possible views of the charge partitioning are discussed. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Effect of composition and particle morphology on the electrochemical properties of LaNi{sub 5}-based alloy electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Spodaryk, Mariana, E-mail: poshtamary@ukr.net [Institute for Problems of Materials Science, NAS of Ukraine, 3 Krzhyzhanovsky Str., 03680 Kyiv-142 (Ukraine); Shcherbakova, Larisa; Sameljuk, Anatoly [Institute for Problems of Materials Science, NAS of Ukraine, 3 Krzhyzhanovsky Str., 03680 Kyiv-142 (Ukraine); Zakaznova-Herzog, Valentina; Braem, Beat; Holzer, Marco; Mauron, Philippe; Remhof, Arndt [Division ‘Hydrogen and Energy’, EMPA Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Solonin, Yurii [Institute for Problems of Materials Science, NAS of Ukraine, 3 Krzhyzhanovsky Str., 03680 Kyiv-142 (Ukraine); Züttel, Andreas [Division ‘Hydrogen and Energy’, EMPA Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf (Switzerland)

    2014-09-01

    Highlights: • Characteristics of Al and Co in substituted gas-atomised alloy electrodes is shown. • Surface composition determines the kinetics and stability of the electrodes. • Corrosion of the Al leads to faster kinetics as compared to the Co-containing alloys. - Abstract: Al and Co substituted LaNi{sub 5}-based intermetallic compounds were investigated as negative electrode materials in alkaline KOH-electrolyte. The structure, morphology and electrochemical properties of gas-atomised and cast LaNi{sub 4.5}Al{sub 0.5} and LaNi{sub 2.5}Co{sub 2.4}Al{sub 0.1} alloys were investigated and the effect of the substitutions and the production method on the surface and bulk composition is compared to cast LaNi{sub 5} as a reference. While the rapid solidification of the gas-atomised alloys affects the site energy distribution for hydrogen on the interstitial sites, the activation and degradation mechanism of the electrodes cycle life is dominated by the elemental composition of the alloy and especially the surface. Therefore, the alloys with the larger Al content activate within a few cycles and also degrade faster as compared to the alloys with a high Co content. Furthermore, the dissolution of Al leads to a highly active surface with a lower reaction resistance, which leads to an order of magnitude increased high rate dischargeability.

  6. High-pressure studies on a new superconducting clathrate: Ba sub 6 Ge sub 2 sub 5

    CERN Document Server

    Yuan, H Q; Carrillo-Cabrera, W; Paschen, S; Sparn, G; Baenitz, M; Grin, Y; Steglich, F

    2002-01-01

    The effect of pressure on the low-temperature states of the newly discovered clathrate Ba sub 6 Ge sub 2 sub 5 is investigated by means of measurements of the electrical resistivity. At ambient pressure, Ba sub 6 Ge sub 2 sub 5 undergoes a two-step structural phase transition between 230 and 180 K from metallic behaviour to a high-resistivity state characterized by a mean free path of about 3 A. Interestingly, a Bardeen-Cooper-Schrieffer-like (BCS-like) superconducting transition occurs at T sub C approx 0.24 K from the resulting 'bad metal'. With increasing pressure, the structural phase transition is depressed but T sub C increases drastically. T sub C reaches a maximum value of 3.85 K at the critical pressure p sub C approx 2.8 GPa, where the structural distortion is completely suppressed and the system exhibits metallic behaviour. Higher pressures lead to a slight decrease of T sub C.

  7. 3D Orientational Control in Self-Assembled Thin Films with Sub-5 nm Features by Light.

    Science.gov (United States)

    Nickmans, Koen; Bögels, Gerardus M; Sánchez-Somolinos, Carlos; Murphy, Jeffrey N; Leclère, Philippe; Voets, Ilja K; Schenning, Albertus P H J

    2017-09-01

    While self-assembled molecular building blocks could lead to many next-generation functional organic nanomaterials, control over the thin-film morphologies to yield monolithic sub-5 nm patterns with 3D orientational control at macroscopic length scales remains a grand challenge. A series of photoresponsive hybrid oligo(dimethylsiloxane) liquid crystals that form periodic cylindrical nanostructures with periodicities between 3.8 and 5.1 nm is studied. The liquid crystals can be aligned in-plane by exposure to actinic linearly polarized light and out-of-plane by exposure to actinic unpolarized light. The photoalignment is most efficient when performed just under the clearing point of the liquid crystal, at which the cylindrical nanostructures are reoriented within minutes. These results allow the generation of highly ordered sub-5 nm patterns in thin films at macroscopic length scales, with control over the orientation in a noncontact fashion. © 2017 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Palladium mixed-metal surface-modified AB<sub>5-type intermetallides enhance hydrogen sorption kinetics

    Directory of Open Access Journals (Sweden)

    Roman V. Denys

    2010-09-01

    Full Text Available Surface engineering approaches were adopted in the preparation of advanced hydrogen sorption materials, based on ‘low-temperature’, AB<sub>5-type intermetallides. The approaches investigated included micro-encapsulation with palladium and mixed-metal mantles using electroless plating. The influence of micro-encapsulation on the surface morphology and kinetics of hydrogen charging were investigated. It was found that palladium-nickel (Pd-Ni co-deposition by electroless plating significantly improved the kinetics of hydrogen charging of the AB<sub>5-type intermetallides at low hydrogen pressure and temperature, after long-term pre-exposure to air. The improvement in the kinetics of hydrogen charging was credited to a synergistic effect between the palladium and nickel atoms in the catalytic mantle and the formation of an ‘interfacial bridge’ for hydrogen diffusion by the nickel atoms in the deposited layer. The developed surface-modified materials may find application in highly selective hydrogen extraction, purification, and storage from impure hydrogen feeds.

  9. Study of structural and optical properties of ZnAlQ{sub 5} (zinc aluminum quinolate) organic phosphor for OLED applications

    Energy Technology Data Exchange (ETDEWEB)

    Nagpure, I. M., E-mail: indrajitnagpure@gmail.com; Painuly, Deepshikha [Physics, Department of Sciences and Humanities, National Institute of Technology,Uttarakhand-246174 (India); Rabanal, Maria Eugenia [Department of Materials Science and Engineering and Chemical Engineering,University Carlos III of Madrid, Avd. Universidad 30, 28911 Leganes, Madrid (Spain)

    2016-05-06

    The various composition of ZnAlQ{sub 5} such as Zn{sub 1.5}A{sub 10.5}Q{sub 5}, Zn{sub 1}Al{sub 1}Q{sub 5}, Zn{sub 0.5}Al{sub 1.5}Q{sub 5} organic phosphors were prepared via simple cost effective co-precipitation method. The FTIR, SEM, photoluminescence analysis of the prepared phosphors were reported. ZnQ{sub 2} and AlQ{sub 3} were also prepared by similar method and their properties were compared with different composition of ZnAlQ{sub 5}. The structural elucidation in the form of stretching frequencies of chemical bonds of the prepared phosphor was carried out using Fourier Transform Infrared Spectroscopy (FTIR). The stretching frequency analysis confirms the formation of prepared phosphor materials. The SEM analysis shows the surface morphological behavior of prepared phosphor materials. Greenish photoluminescence were observed at 505 to 510 nm for the different composition of ZnAlQ{sub 5},in which Zn{sub 1.5}Al{sub 0.5}Q{sub 5} shows maximum luminescence intensity at 505 nm. PL emission of ZnQ{sub 2} was observed at 515 nm, while for AlQ{sub 3} at 520 nm. The blue shift of 10 nm was observed in Zn{sub 1.5}A{sub 10.5}Q{sub 5} due to modification of energy level due to presence of Zn{sup 2+} and Al{sup 3+}. The enhancement in PL intensity was observed in Zn{sub 1.5}A{sub 10.5}Q{sub 5} compared to the other composition due to transfer of energy between Zn{sup 2+} and quinolate complex. Optical properties of the prepared materials were evaluated for possible applications in organic light emitting devices (OLED).

  10. Direct pumping of ultrashort Ti:sapphire lasers by a frequency doubled diode laser

    DEFF Research Database (Denmark)

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika

    2011-01-01

    A simple and robust diode laser system emitting 1.28 W of green light suitable for pumping an ultrafast Ti:sapphire laser is presented. To classify our results, the diode laser is compared to a standard, commercially available diode pumped solid-state (DPSS) laser system pumping the same oscillator....... When using our diode laser system, the optical conversion efficiencies from green to near-infrared light reduces to 75 % of the values achieved with the commercial pump laser. Despite this reduction the overall efficiency of the Ti: sapphire laser is still increased by a factor > 2 due to the superior...... electro-optical efficiency of the diode laser. Autocorrelation measurements show that pulse widths of less than 20 fs can be expected with an average power of 52 mW when using our laser. These results indicate the high potential of direct diode laser pumped Ti: sapphire lasers to be used in applications...

  11. Second harmonic generation of spectrally broadened femtosecond ytterbium laser radiation in a gas-filled capillary

    Energy Technology Data Exchange (ETDEWEB)

    Didenko, N V; Konyashchenko, Aleksandr V; Kostryukov, P V; Losev, Leonid L; Tenyakov, S Yu

    2011-09-30

    A 300-fs radiation pulse of an ytterbium laser with a wavelength of 1030 nm and energy of 150 {mu}J were converted to a 15-fs pulse with a wavelength of 515 nm by broadening the emission spectrum in a capillary filled with xenon and by generating the second harmonic in a KDP crystal. The energy efficiency of the conversion was 30 %.

  12. Preliminary results of femtosecond laser-assisted descemet stripping endothelial keratoplasty

    NARCIS (Netherlands)

    Cheng, Yanny Y. Y.; Hendrikse, Fred; Pels, Elisabeth; Wijdh, Robert-Jan; van Cleynenbreugel, Hugo; Eggink, Cathariena A.; van Rij, Gabriel; Rijneveld, Wilhelmina J.; Nuijts, Rudy M. M. A.

    2008-01-01

    Objective: To evaluate the preliminary visual results of femtosecond laser-assisted descemet stripping endothelial keratoplasty (FS-DSEK). keratoplasty (FS-DSEK). Methods: We prospectively analyzed results of 20 consecutive patients with Fuchs endothelial dystrophy or aphakic/pseudophakic bullous

  13. Femtosecond laser-matter interaction theory, experiments and applications

    CERN Document Server

    Gamaly, Eugene G

    2011-01-01

    Basics of Ultra-Short Laser-Solid InteractionsSubtle Atomic Motion Preceding a Phase Transition: Birth, Life and Death of PhononsUltra-Fast Disordering by fs-Lasers: Superheating Prior to Entropy CatastropheAblation of SolidsUltra-Short Laser-Matter Interaction Confined Inside a Bulk of Transparent SolidApplications of Ultra-Short Laser-Matter InteractionsConclusion Remarks.

  14. Angular emission of ions and mass deposition from femtosecond and nanosecond laser-produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Verhoff, B.; Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2012-06-15

    We investigated the angular distribution of ions and atoms emanating from femto- and nanosecond laser-produced metal plasmas under similar laser fluence conditions. For producing plasmas, aluminum targets are ablated in vacuum employing pulses from a Ti:Sapphire ultrafast laser (40 fs, 800 nm) and an Nd:YAG laser (6 ns, 1064 nm). The angular distribution of ion emission as well as the kinetic energy distribution is characterized by a Faraday cup, while a quartz microbalance is used for evaluating deposited mass. The ion and deposited mass features showed that fs laser ablated plasmas produced higher kinetic energy and more mass per pulse than ns plumes over all angles. The ion flux and kinetic energy studies show fs laser plasmas produce narrower angular distribution while ns laser plasmas provide narrower energy distribution.

  15. Angular emission of ions and mass deposition from femtosecond and nanosecond laser-produced plasmas

    Science.gov (United States)

    Verhoff, B.; Harilal, S. S.; Hassanein, A.

    2012-06-01

    We investigated the angular distribution of ions and atoms emanating from femto- and nanosecond laser-produced metal plasmas under similar laser fluence conditions. For producing plasmas, aluminum targets are ablated in vacuum employing pulses from a Ti:Sapphire ultrafast laser (40 fs, 800 nm) and an Nd:YAG laser (6 ns, 1064 nm). The angular distribution of ion emission as well as the kinetic energy distribution is characterized by a Faraday cup, while a quartz microbalance is used for evaluating deposited mass. The ion and deposited mass features showed that fs laser ablated plasmas produced higher kinetic energy and more mass per pulse than ns plumes over all angles. The ion flux and kinetic energy studies show fs laser plasmas produce narrower angular distribution while ns laser plasmas provide narrower energy distribution.

  16. Laser photoionization of triacetone triperoxide (TATP) by femtosecond and nanosecond laser pulses

    Science.gov (United States)

    Mullen, Christopher; Huestis, David; Coggiola, Michael; Oser, Harald

    2006-05-01

    Laser ionization time-of-flight mass spectrometry has been applied to the study of triacetone triperoxide (TATP), an improvised explosive. Wavelength dependent mass spectra in two time regimes were acquired using nanosecond (5 ns) and femtosecond (130 fs) laser pulses. We find the major difference between the two time regimes to be the detection of the parent molecular ion when femtosecond laser pulses are employed.

  17. A determination of the oxygen non-stoichiometry of the oxygen storage materials LnBaMn{sub 2}O{sub 5+δ} (Ln=Gd, Pr)

    Energy Technology Data Exchange (ETDEWEB)

    Jeamjumnunja, Kannika; Gong, Wenquan; Makarenko, Tatyana; Jacobson, Allan J., E-mail: ajjacob@uh.edu

    2016-07-15

    The A-site ordered double-perovskite oxides, LnBaMn{sub 2}O{sub 5+δ} (Ln=Gd, Pr), were synthesized and investigated to understand the effect of A site cation substitution on the oxygen storage properties of these materials. The present results are compared with our previous data for YBaMn{sub 2}O{sub 5+δ}. The results clearly reveal that changing the Ln cation strongly influences the oxidation/reduction behavior of LnBaMn{sub 2}O{sub 5+δ}. Based on thermogravimetric analysis data, oxygen uptake begins at lower temperatures in both air and oxygen in compounds with Ln{sup 3+} ions larger than Y{sup 3+}. These oxides exhibit almost complete and reversible oxygen uptake/release between fully-reduced LnBaMn{sub 2}O{sub 5} and fully-oxidized LnBaMn{sub 2}O{sub 6} during changes of the oxygen partial pressure between air and 1.99% H{sub 2}/Ar. In addition, the oxygen non-stoichiometries of GdBaMn{sub 2}O{sub 5+δ} and PrBaMn{sub 2}O{sub 5+δ} were determined as a function of pO{sub 2} at 600, 650, 700 and 750 °C by Coulometric titration at near-equilibrium conditions. The results confirm that these materials have two distinct phases on oxidation/reduction with δ≈0, 0.5 and a third phase with a range of composition with an oxygen content (5+δ) approaching ~6. The stabilities of the LnBaMn{sub 2}O{sub 5+δ} phases extend over a wide range of oxygen partial pressures (∼10{sup −25}≤pO{sub 2} (atm)≤∼1) depending on temperature. Isothermal experiments show that the larger the Ln{sup 3+} cation the lower pO{sub 2} for phase conversion. At some temperatures and pO{sub 2} conditions, the LnBaMn{sub 2}O{sub 5+δ} compounds are unstable with respect to decomposition to BaMnO{sub 3−δ} and LnMnO{sub 3}. This instability is more apparent in Coulometric titration experiments than in thermogravimetric analysis. The Coulometric titration experiments are necessarily slow in order to achieve equilibrium oxygen compositions. - Graphical abstract: Structure of Ln

  18. EST Table: FS884343 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available 48 %/152 aa gnl|Amel|GB11154-PA 10/09/10 52 %/153 aa gi|91079562|ref|XP_966370.1| PREDICTED: similar to iodotyrosine dehalogenase 1, partial [Tribolium castaneum] FS793821 ftes ...

  19. SeaWiFS_L3b_SNSP_LAND

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  20. SeaWiFS_L3b_MO_CDOM

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  1. SeaWiFS_L3b_YR_LAND

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  2. SeaWiFS_L3b_SNSU_CDOM

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  3. SeaWiFS_L3b_SCSU_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  4. SeaWiFS_L3b_SCAU_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  5. SeaWiFS_L3b_CU_POC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  6. SeaWiFS_L3b_SNSU_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  7. SeaWiFS_L3b_MO_PAR

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  8. SeaWiFS_L3b_SCSP_CDOM

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  9. SeaWiFS_L3b_SNSU_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  10. SeaWiFS_L3b_WC_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  11. SeaWiFS_L3b_DAY_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  12. SeaWiFS_L3b_SCAU_LAND

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  13. SeaWiFS_L3b_WC_POC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  14. SeaWiFS_L3b_SNWI_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  15. SeaWiFS_L3b_YR_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  16. SeaWiFS_L3b_SNSP_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  17. SeaWiFS_L3b_MC_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  18. SeaWiFS_L3b_CU_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  19. SeaWiFS_L3b_WC_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  20. SeaWiFS_L3b_DAY_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  1. SeaWiFS_L3b_SNWI_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  2. EST Table: FS890234 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available ar to sorting and assembly machinery component 50 homolog [Tribolium castaneum] 10/09/12 low homology 10/08/...lar to sorting and assembly machinery component 50 homolog [Tribolium castaneum] FS904485 ftes ...

  3. SeaWiFS_L3b_SNAU_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  4. SeaWiFS_L3b_MC_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  5. SeaWiFS_L3b_DAY_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  6. SeaWiFS_L3b_SNAU_CDOM

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  7. EST Table: FS748350 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available PREDICTED: similar to fetal alzheimer antigen, falz [Nasonia vitripennis] 10/09/08 37 %/193 aa FBpp0290563|E...811424.1| PREDICTED: similar to fetal alzheimer antigen, falz [Tribolium castaneum] FS748350 caL- ...

  8. SeaWiFS_L3b_SCWI_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  9. SeaWiFS_L3b_SCSU_PAR

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  10. SeaWiFS_L3b_MO_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  11. SeaWiFS_L3b_MC_PAR

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  12. SeaWiFS_L3b_SCWI_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  13. SeaWiFS_L3b_SNSU_PAR

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  14. SeaWiFS_L3b_SNSP_POC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  15. SeaWiFS_L3b_YR_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  16. SeaWiFS_L3b_SCSP_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  17. SeaWiFS_L3m_GSM

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  18. SeaWiFS_L3b_GSM

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  19. SeaWiFS_L3b_SNSP_PAR

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  20. SeaWiFS_L3b_SCSP_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  1. EST Table: FS796464 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available ar to putative lysosomal glucocerebrosidase [Tribolium castaneum] 10/09/09 32 %/334 aa FBpp0237202|DvirGJ227...milar to putative lysosomal glucocerebrosidase [Tribolium castaneum] FS796494 ffbm ...

  2. EST Table: FS759318 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available 25 aa ref|XP_975608.1| PREDICTED: similar to putative lysosomal glucocerebrosidas...%/225 aa gi|91087345|ref|XP_975608.1| PREDICTED: similar to putative lysosomal glucocerebrosidase [Tribolium castaneum] FS759318 fcaL ...

  3. SeaWiFS_L3b_SNAU_POC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  4. SeaWiFS_L3b_SNSP_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  5. SeaWiFS_L3b_CU_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  6. SeaWiFS_L3b_SNWI_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  7. EST Table: FS745067 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available DICTED: similar to Protein SDA1 homolog (Mystery protein 45A) [Tribolium castaneum] gb|EFA00563.1| hypotheti...imilar to Protein SDA1 homolog (Mystery protein 45A) [Tribolium castaneum] FS745067 bmmt ...

  8. EST Table: FS731272 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available DICTED: similar to Protein SDA1 homolog (Mystery protein 45A) [Tribolium castaneum] gb|EFA00563.1| hypotheti...imilar to Protein SDA1 homolog (Mystery protein 45A) [Tribolium castaneum] FS731272 bmmt ...

  9. Li{sub 5}Cr{sub 9}Ti{sub 4}O{sub 24}: A new anode material for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chunfu, E-mail: linchunfu@hainu.edu.cn [Key Laboratory of Ministry of Education for Advanced Materials in Tropical Island Resources, College of Materials and Chemical Engineering, Hainan University, Haikou 570228, Hainan (China); Deng, Shengjue; Shen, Hong; Wang, Guizhen; Li, Yanfang; Yu, Lei; Lin, Shiwei; Li, Jianbao [Key Laboratory of Ministry of Education for Advanced Materials in Tropical Island Resources, College of Materials and Chemical Engineering, Hainan University, Haikou 570228, Hainan (China); Lu, Li, E-mail: luli@nus.edu.sg [Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576 (Singapore)

    2015-11-25

    Li{sub 4}Ti{sub 5}O{sub 12} suffers from its small theoretical capacity and low conductivity, limiting its practical applications in lithium-ion batteries. Although its conductivity has been improved, its theoretical capacity has not been increased so far. Here, for the first time, the capacity of Li{sub 4}Ti{sub 5}O{sub 12} is increased by combining Ti{sup 3+}/Ti{sup 4+} and Cr{sup 2+}/Cr{sup 3+} redox couples. Spinel Li{sub 5}Cr{sub 9}Ti{sub 4}O{sub 24} with a larger theoretical capacity of 323 mAh g{sup −1} is designed and fabricated through a facile solid-state reaction method. The as-fabricated Li{sub 5}Cr{sub 9}Ti{sub 4}O{sub 24} delivers a large initial discharge capacity of 311 mAh g{sup −1} between 3 and 0.001 V (vs. Li/Li{sup +}) at a current density of 62.5 mA g{sup −1}, which is larger than that of Li{sub 4}Ti{sub 5}O{sub 12}. Furthermore, it exhibits good (electronic and ionic) conductivity and a high rate performance. - Highlights: • Capacity of Li{sub 4}Ti{sub 5}O{sub 12} is increased by combining Ti{sup 3+}/Ti{sup 4+} and Cr{sup 2+}/Cr{sup 3+} couples. • Spinel Li{sub 5}Cr{sub 9}Ti{sub 4}O{sub 24} with a larger theoretical capacity of 323 mAh g{sup −1} is prepared. • Discharge and charge capacities of Li{sub 5}Cr{sub 9}Ti{sub 4}O{sub 24} are larger than those of Li{sub 4}Ti{sub 5}O{sub 12}. • Li{sub 5}Cr{sub 9}Ti{sub 4}O{sub 24} shows a large electronic conductivity and Li{sup +} diffusion coefficient. • Li{sub 5}Cr{sub 9}Ti{sub 4}O{sub 24} further exhibits an ultra-high rate performance and good cyclability.

  10. Comparative shock wave analysis during corneal ablation with an excimer laser, picosecond laser, and femtosecond laser

    Science.gov (United States)

    Krueger, Ronald R.; Juhasz, Tibor

    1995-05-01

    With the event of topographic steep central islands following excimer laser surgery and the potential damage to the corneal endothelium, shock waves are playing an increasingly important role in laser refractive surgery. With this in mind, we performed a comparative shock wave analysis in corneal tissue using an excimer laser, picosecond laser, and femtosecond laser. We used a Lambda Physik excimer laser at 308 nm wavelength, a Nd:YLF picosecond laser at 1053 nm wavelength and a synchronously pumped linear cavity femtosecond laser at 630 nm wavelength. The pulse widths of the corresponding lasers were 8 ns, 18 ps, 150 fs, respectively. The energy density of irradiation was 2.5 to 8 times the threshold level being 2 J/cm2 (excimer laser), 86 J/cm2 (picosecond laser) and 10.3 J/cm2 (femtosecond laser). Shock wave dynamics were analyzed using time-resolved photography on a nanosecond time scale using the picosecond laser in corneal tissue, water and air. Shock wave dynamics using the femtosecond laser were studied in water only while the excimer laser induced shock wave during corneal ablation was studied in air only. We found the dynamics of shock waves to be similar in water and corneal tissue indicating that water is a good model to investigate shock wave effects in the cornea. The magnitude of the shock wave velocity and pressure decays over time to that of a sound wave. The distance over which it decays is 3 mm in air with the excimer laser and 600 - 700 micrometers in air with the picosecond laser. In water, the picosecond laser shock wave decays over a distance of 150 micrometers compared to the femtosecond laser shock wave which decays over a distance of 30 micrometers . Overall the excimer laser shock wave propagates 5 times further than that of the picosecond laser and the picosecond laser shock wave propagates 5 times further than that of the femtosecond laser. In this preliminary comparison, the time and distance for shock wave decay appears to be directly

  11. High oxidation state monopentamethylcyclopentadienyl tungsten methyl complexes including the first d/sup 0/ complex containing a highly distorted methylene ligand, W(eta/sup 5/-C/sub 5/Me/sub 5/)(CH/sub 3/)/sub 3/(CH/sub 2/)

    Energy Technology Data Exchange (ETDEWEB)

    Liu, A.H.; Murray, R.C.; Dewan, J.C.; Santarsiero, B.D.; Schrock, R.R.

    1987-07-08

    Mono-eta/sup 5/-C/sub 5/H/sub 5/ complexes are among the most common in organometallic chemistry. After pentamethylcyclopentadiene became readily available, many mono-eta/sup 5/-C/sub 5/Me/sub 5/ analogues were prepared and their chemistry compared with that of known eta/sup 5/-C/sub 5/H/sub 5/ complexes. Soon mono-eta/sup 5/-C/sub 5/Me/sub 5/ (Cp*) complexes were discovered that had no eta/sup 5/-C/sub 5/H/sub 5/ analogues, e.g., TaCp*(olefin)Cl/sub 2/ and IrCp*H/sub 2/(SiMe/sub 3/)/sub 2/. Such a circumstance appears to be more common when the metal is in a relatively high oxidation state. One of the likely reasons the Cp* ligand apparently stabilizes high oxidation states is its now well-documented ability to donate electron density to the metal. Another important reason is that decomposition pathways involving eta/sup 5/-C/sub 5/H/sub 5/ ring protons are blocked. Relatively recently the authors discovered that (W(eta/sup 5/-C/sub 5/Me/sub 4/-t-Bu)Cl/sub 4/)/sub 2/ was a product of the reaction between the tungstacyclobutadiene complex W(C(t-Bu)C(Me)C(Me))Cl/sub 3/ and 2-butyne. They soon developed a practical route to the eta/sup 5/-C/sub 5/Me/sub 5/ analog and found that WCp*Me/sub 4/ could be prepared readily. They were interested in WCp*Me/sub 4/ first as a means of preparing hydride complexes such as (WCp*H/sub 3/)/sub 4/ and (WCp*H/sub 4/)/sub 2/, but then they became interested in exploring its chemistry per se. In this paper they report the first collection of results concerning the chemistry of WCp*Me/sub 4/ and related methyl complexes.

  12. Intermetallic M--Sn.sub.5 (M=Fe, Cu, Co, Ni) compound and a method of synthesis thereof

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiao-Liang; Han, Weiqiang

    2017-09-05

    Novel intermetallic materials are provided that are composed of tin and one or more additional metal(s) having a formula M.sub.(1-x)-Sn.sub.5, where -0.1.ltoreq.x.ltoreq.0.5, with 0.01.ltoreq.x.ltoreq.0.4 being more preferred and the second metallic element (M) is selected from iron (Fe), copper (Cu), cobalt (Co), nickel (Ni), and a combination of two or more of those metals. Due to low concentration of the second metallic element, the intermetallic compound affords an enhanced capacity applicable for electrochemical cells and may serve as an intermediate phase between Sn and MSn.sub.2. A method of synthesizing these intermetallic materials is also disclosed.

  13. Mechanochemically synthesized sub-5 nm sized CuS quantum dots with high visible-light-driven photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shun; Ge, Zhen-Hua [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Bo-Ping, E-mail: bpzhang@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Yao, Yao [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Huan-Chun [School of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); Yang, Jing; Li, Yan; Gao, Chao [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Lin, Yuan-Hua [School of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China)

    2016-10-30

    Highlights: • CuS quantum dots (<5 nm) were synthesized by mechanochemical ball milling. • Defects was observed in the CuS quantum dots. • They show good visible light photocatalytic activity as Fenton-like reagents. - Abstract: We report a simple mechanochemical ball milling method for synthesizing monodisperse CuS quantum dots (QDs) with sizes as small as sub-5 nm. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV–vis spectroscopy. The CuS QDs exhibited excellent visible-light-driven photocatalytic activity and stability for degradation of Rodanmine B aqueous solution as Fenton-like reagents. Our study opens the opportunity to low-cost and facile synthesis of QDs in large scale for future industrial applications.

  14. A closer look at two AdS{sub 4} branes in an AdS{sub 5} bulk

    Energy Technology Data Exchange (ETDEWEB)

    Thambyahpillai, Shiyamala [Harvard University, Department of Pysics, Cambridge, Massachusetts (United States)]. E-mail: thamby@physics.harvard.edu

    2005-02-01

    We investigate a scenario with two AdS{sub 4} branes in an AdS{sub 5} bulk. In this scenario there are two gravitons and we investigate the role played by each of them for different positions of the second brane. We show that both gravitons play a significant role only when the turn-around point in the warp factor is approximately equidistant from both branes. We find that the ultralight mode becomes heavy as the second brane approaches the turn-around point, and the physics begins to resemble that of the RS model. Thus we demonstrate the crucial role played by the turn-around in the warp factor in enabling the presence of both gravitons. (author)

  15. Performance of copper-doped V{sub 2}O{sub 5} xerogel in coin cell assembly

    Energy Technology Data Exchange (ETDEWEB)

    Coustier, F.; Jarero, G.; Passerini, S.; Smyrl, W.H. [Minnesota Univ., Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science

    1999-10-01

    Copper-doped, vanadium pentoxide xerogel is prepared through a simple sol-gel procedure, followed by heterogeneous doping and freeze-drying. Composite cathodes were formed by spray-coating a mixture of the Cu-doped material, carbon, and binder onto aluminum foils. The composite cathodes were studied in 2016 coin cells with lithium anodes and supported liquid electrolyte. The electrochemical performance of the doped material is excellent. Up to 2.2 mol of lithium per mol of doped V{sub 2}O{sub 5} can be reversibly intercalated. The composite cathodes also showed very high intercalation rate performance and an excellent cyclability with no capacity fading over a few hundred cycles (>450). (orig.)

  16. The effects of heat treatment on optical, structural, electrochromic and bonding properties of Nb{sub 2}O{sub 5} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Coşkun, Özlem Duyar, E-mail: duyar@hacettepe.edu.tr [Hacettepe University, Department of Physics Engineering, Thin Film Preparation and Characterization Laboratory, Ankara (Turkey); Demirel, Selen, E-mail: nymph24@gmail.com [Hacettepe University, Department of Physics Engineering, Thin Film Preparation and Characterization Laboratory, Ankara (Turkey); Hacettepe University, Nanotechnology and Nanomedicine Department, Ankara (Turkey); Atak, Gamze, E-mail: gbaser@hacettepe.edu.tr [Hacettepe University, Department of Physics Engineering, Thin Film Preparation and Characterization Laboratory, Ankara (Turkey)

    2015-11-05

    Nb{sub 2}O{sub 5} thin films were deposited onto heated glass substrates by RF magnetron sputtering using a Nb{sub 2}O{sub 5} target. The films were annealed in air at temperatures between 400 and 700 °C for 6 h. Effects of the crystalline structure on optical, structural, electrochromic and bonding properties of the Nb{sub 2}O{sub 5} thin films were investigated by X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, optical spectrophotometry and electrochemical measurements. The film refractive index varied between 2.09 and 2.22 at the wavelength of 550 nm depending on the annealing temperature. The decrease of the optical band gap revealed for the films with increasing annealing temperature is attributed to oxygen-ion vacancies in the film structure. The orthorhombic structure of Nb{sub 2}O{sub 5} films resulted in good electrochromic properties with high colouration efficiencies of 19.56 cm{sup 2}/C and 53.24 cm{sup 2}/C at 550 nm and 1000 nm, respectively. The optical, structural and electrochromic properties of the different crystalline polymorphic forms of the Nb{sub 2}O{sub 5} films make them attractive for optical applications. - Highlights: • Stoichiometric Nb{sub 2}O{sub 5} films prepared using RF magnetron sputtering technique. • The different crystalline forms of Nb{sub 2}O{sub 5} thin films obtained by annealing. • The optical, structural and electrochromic properties of the films were investigated. • The optical band gap decreased with increasing annealing temperature. • The orthorhombic T-Nb{sub 2}O{sub 5} films exhibited a higher colouration efficiency.

  17. Fast response of sprayed vanadium pentoxide (V{sub 2}O{sub 5}) nanorods towards nitrogen dioxide (NO{sub 2}) gas detection

    Energy Technology Data Exchange (ETDEWEB)

    Mane, A.A. [Thin Film Nanomaterials Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004 (India); General Science and Humanities Department, Sant Gajanan Maharaj College of Engineering, Mahagaon, 416 503 (India); Suryawanshi, M.P. [Optoelectronics Convergence Research Center, Department of Materials Science and Engineering, Chonnam National University, 300, Yongbong-Dong, Buk-Gu, Gwangju 500-757 (Korea, Republic of); Kim, J.H., E-mail: jinhyeok@chonnam.ac.kr [Optoelectronics Convergence Research Center, Department of Materials Science and Engineering, Chonnam National University, 300, Yongbong-Dong, Buk-Gu, Gwangju 500-757 (Korea, Republic of); Moholkar, A.V., E-mail: avmoholkar@gmail.com [Thin Film Nanomaterials Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004 (India)

    2017-05-01

    Highlights: • Effect of solution concentration on physicochemical properties of sprayed V{sub 2}O{sub 5} nanorods is studied. • Good response and short response-recovery times of V{sub 2}O{sub 5} nanorods towards NO{sub 2} gas show it is potential material for fabrication of NO{sub 2} sensor. • The chemisorption mechanism of NO{sub 2} gas on the V{sub 2}O{sub 5} nanorods is discussed. - Abstract: The V{sub 2}O{sub 5} nanorods have been successfully spray deposited at optimized substrate temperature of 400 °C onto the glass substrates using vanadium trichloride (VCl{sub 3}) solution of different concentrations. The effect of solution concentration on the physicochemical and NO{sub 2} gas sensing properties of sprayed V{sub 2}O{sub 5} nanorods is studied at different operating temperatures and gas concentrations. The XRD study reveals the formation of V{sub 2}O{sub 5} having an orthorhombic symmetry. The FE-SEM micrographs show the nanorods-like morphology of V{sub 2}O{sub 5}. The AFM micrographs exhibit a well covered granular surface topography. For direct allowed transition, the band gap energy values are found to be decreased from 2.45 eV to 2.42 eV. The nanorods deposited with 30 mM solution concentration shows the maximum response of 24.2% for 100 ppm NO{sub 2} gas concentration at an operating temperature of 200 °C with response and recovery times of 13 s and 140 s, respectively. Finally, the chemisorption mechanism of NO{sub 2} gas on the V{sub 2}O{sub 5} nanorods is discussed.

  18. Thermal properties of (Dy{sub x}Gd{sub 1-x}){sub 3}Ga{sub 5}O{sub 12} garnet single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Numazawa, T.; Kimura, H.; Maeda, H. [Tsukuba Magnet Labs., Tsukuba (Japan)] [and others

    1997-06-01

    The solid solution (Dy{sub x}Gd{sub 1-x}){sub 3}Ga{sub 5}O{sub 12} garnet is proposed as a high heat capacity material below 2 K for regenerator. A short range order interaction resulting from the magnetic frustration in Gd{sub 3}Ga{sub 5}O{sub 12} gives a considerably high heat capacity below 2 K. At a magnetic field B = {approximately}1 T, Gd{sub 3}Ga{sub 5}O{sub 12} has a sharp anomaly in its specific heat at {approximately}0.37 K related to an antiferromagnetic transition, keeping the large heat capacity. By substituting Gd ion by Dy ion, an anisotropy will be produced in (Dy{sub x}Gd{sub 1-x}){sub 3}Ga{sub 5}O{sub 12} and it enhances the antiferromagnetic long range order interactions. The specific heat measurement for (Dy{sub 0.5}Gd{sub 0.5}){sub 3}Ga{sub 5}O{sub 12} at B = 0 T showed that heat capacity of (Dy{sub 0.5}Gd{sub 0.5}){sub 3}Ga{sub 5}O{sub 12} is comparable largely to that of Gd{sub 3}Ga{sub 5}O{sub 12} and a transition temperature may be found below 0.6 K. From the thermal conductivity measurement, a strong correlation with magnetic field has been found. The reduction in the thermal conductivity caused by the magnetic field is the largest in Dy{sub 3}Ga{sub 5}O{sub 12} and it decreases by increasing the concentration of Gd ion.

  19. Magneto caloric effect in (Dy{sub x}Gd{sub 1-x}){sub 3}Ga{sub 5}O{sub 12} for adiabatic demagnetization refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Numazawa, Takenori; Kamiya, Koji; Okano, Takahiro; Matsumoto, Koichi

    2003-05-01

    Gadolinium and dysprosium gallium garnet single crystals (Dy{sub x}Gd{sub 1-x}){sub 3}Ga{sub 5}O{sub 12} (x=0,0.5 and 1) have been investigated for adiabatic demagnetization refrigeration used as magnetic materials between 0.5 and 5 K. Specific heat measurement of (Dy{sub 0.5}Gd{sub 0.5}){sub 3}Ga{sub 5}O{sub 12} showed a large and broad peak similar to that of Gd{sub 3}Ga{sub 5}O{sub 12} and it suggests that the geometrical frustration in Gd{sub 3}Ga{sub 5}O{sub 12} still remains in (Dy{sub 0.5}Gd{sub 0.5}){sub 3}Ga{sub 5}O{sub 12}. Magneto caloric effect of (Dy{sub 0.5}Gd{sub 0.5}){sub 3}Ga{sub 5}O{sub 12} was about four times larger than that of Gd{sub 3}Ga{sub 5}O{sub 12} for the magnetic field of 1 T between 0.5 and 5 K. Therefore, the magnetic entropy change of Gd{sub 3}Ga{sub 5}O{sub 12} by the external magnetic fields could be enhanced by substituting Dy{sup 3+} ion for Gd{sup 3+} ion for the magnetic fields of <2 T between 0.5 and 5 K.

  20. Effect of strip temperature on the formation of an Fe{sub 2}Al{sub 5} inhibition layer during hot-dip galvanizing

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Monojit [R and D Division, Tata Steel Ltd., Jamshedpur 831001 (India)], E-mail: monoron@yahoo.com; Singh, Shiv Brat [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur 721302 (India)

    2009-04-15

    The theory of nucleation has been employed to derive expressions for the formation of an Fe{sub 2}Al{sub 5} layer during commercial strip galvanizing. This is then used to show the effect of the strip entry temperature on the nucleation of the Fe{sub 2}Al{sub 5} layer. An attempt was also made to verify this effect through controlled experiments in a hot-dip galvanizing simulator and electron microscopic characterization of a few samples.

  1. EST Table: FS748249 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS748249 E_ET_caL-_13N07_F_0 10/09/28 80 %/156 aa ref|XP_001847239.1| arsenical pump-driving...: Full=Arsenite-stimulated ATPase; AltName: Full=Arsenical pump-driving ATPase homolog gb|EDS45868.1| arsenical pump-driving...5|ref|XP_974589.1| PREDICTED: similar to arsenical pump-driving atpase [Tribolium castaneum] FS918630 caL- ...

  2. EST Table: FS908977 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS908977 E_FL_fufe_15N16_F_0 10/09/28 76 %/277 aa ref|XP_001847239.1| arsenical pump-driving...: Full=Arsenite-stimulated ATPase; AltName: Full=Arsenical pump-driving ATPase homolog gb|EDS45868.1| arsenical pump-driving...5|ref|XP_974589.1| PREDICTED: similar to arsenical pump-driving atpase [Tribolium castaneum] FS918630 fufe ...

  3. EST Table: FS853077 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS853077 E_FL_fner_45F16_F_0 10/09/28 78 %/203 aa ref|XP_001847239.1| arsenical pump-driving...: Full=Arsenite-stimulated ATPase; AltName: Full=Arsenical pump-driving ATPase homolog gb|EDS45868.1| arsenical pump-driving...5|ref|XP_974589.1| PREDICTED: similar to arsenical pump-driving atpase [Tribolium castaneum] FS918630 fner ...

  4. EST Table: FS849688 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS849688 E_FL_fner_35L09_F_0 10/09/28 77 %/212 aa ref|XP_001847239.1| arsenical pump-driving...: Full=Arsenite-stimulated ATPase; AltName: Full=Arsenical pump-driving ATPase homolog gb|EDS45868.1| arsenical pump-driving...5|ref|XP_974589.1| PREDICTED: similar to arsenical pump-driving atpase [Tribolium castaneum] FS918630 fner ...

  5. EST Table: FS811717 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS811717 E_FL_fmgV_35J01_F_0 10/09/28 low homology 10/09/09 low homology 10/08/29 4...148#prot ein_id:AAC04462.2 10/09/10 low homology 10/09/10 low homology 10/09/10 low homology FS931748 fmgV ...

  6. EST Table: FS803120 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS803120 E_FL_fmgV_11I07_F_0 10/09/28 74 %/111 aa ref|NP_001034501.1| extradenticle... [Tribolium castaneum] emb|CAD57734.1| extradenticle [Tribolium castaneum] 10/09/09 68 %/113 aa FBpp0123364|...XD_ANOGA 10/09/10 low homology 10/09/10 74 %/111 aa gi|38490515|emb|CAD57734.1| extradenticle [Tribolium castaneum] FS924788 fmgV ...

  7. EST Table: FS898442 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS898442 E_FL_ftes_30N10_R_0 10/09/28 92 %/225 aa ref|NP_001037622.1| timeless [Bom...byx mori] gb|ABD52733.1| timeless [Bombyx mori] 10/09/12 n.h 10/08/29 n.h 10/09/10 low homology 10/09/10 n.h 10/09/10 low homology FS751324 ftes ...

  8. EST Table: FS745261 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS745261 E_FL_bmmt_30M21_R_0 10/09/28 45 %/135 aa gb|ACN52067.1| insect intestinal mucin 3 [Mamestra configu...rata] 10/09/08 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS740161 bmmt ...

  9. EST Table: FS741790 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS741790 E_FL_bmmt_21A21_R_0 10/09/28 48 %/172 aa gb|ACN52067.1| insect intestinal mucin 3 [Mamestra configu...rata] 10/09/07 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS740161 bmmt ...

  10. EST Table: FS742806 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS742806 E_FL_bmmt_23P01_R_0 10/09/28 45 %/155 aa gb|ACN52067.1| insect intestinal mucin 3 [Mamestra configu...rata] 10/09/07 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS740161 bmmt ...

  11. EST Table: FS743730 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS743730 E_FL_bmmt_26H21_R_0 10/09/28 49 %/178 aa gb|ACN52067.1| insect intestinal mucin 3 [Mamestra configu...rata] 10/09/07 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS740161 bmmt ...

  12. EST Table: FS731466 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS731466 E_FL_bmmt_30M21_F_0 10/09/28 46 %/205 aa gb|ACN52067.1| insect intestinal mucin 3 [Mamestra configu...rata] 10/09/03 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS733323 bmmt ...

  13. EST Table: FS728748 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS728748 E_FL_bmmt_14B19_F_0 10/09/28 46 %/205 aa gb|ACN52067.1| insect intestinal mucin 3 [Mamestra configu...rata] 10/09/03 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS733323 bmmt ...

  14. EST Table: FS729582 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS729582 E_FL_bmmt_16H01_F_0 10/09/28 53 %/140 aa gb|ACN52067.1| insect intestinal mucin 3 [Mamestra configu...rata] 10/09/03 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS733323 bmmt ...

  15. EST Table: FS742801 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS742801 E_FL_bmmt_23O20_R_0 10/09/28 46 %/154 aa gb|ACN52067.1| insect intestinal mucin 3 [Mamestra configu...rata] 10/09/07 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS740161 bmmt ...

  16. EST Table: FS912760 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS912760 E_FL_fufe_27D02_F_0 11/12/09 n.h 10/09/28 56 %/251 aa ref|XP_001810438.1| ...l|Amel|GB19927-PA 10/09/10 56 %/251 aa gi|189242283|ref|XP_001810438.1| PREDICTED: similar to wd-repeat protein [Tribolium castaneum] FS912760 fufe ...

  17. EST Table: FS732324 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS732324 E_FL_bmmt_26D13_F_0 10/09/28 90 %/116 aa ref|XP_624457.1| PREDICTED: simil...8 10/09/10 90 %/116 aa gnl|Amel|GB16091-PA 10/09/10 86 %/116 aa gi|91088209|ref|XP_973275.1| PREDICTED: similar to suppressor of Ty 4 homolog 1 [Tribolium castaneum] FS916022 bmmt ...

  18. EST Table: FS763232 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS763232 E_FL_fcaL_33A16_F_0 10/09/28 41 %/216 aa ref|XP_001662018.1| receptor for ...otein|3L:33704151:33705233:1|gene:AGAP011814 10/09/10 n.h 10/09/10 33 %/223 aa gi|91084551|ref|XP_9732...98.1| PREDICTED: similar to receptor for activated C kinase, putative [Tribolium castaneum] FS911322 fcaL ...

  19. EST Table: FS902630 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS902630 E_FL_ftes_48D08_R_0 10/09/28 50 %/212 aa ref|XP_002432616.1| sorting and assembly machine...ry sam50 protein, putative [Pediculus humanus corporis] gb|EEB19878.1| sorting and assembly machine...REDICTED: similar to sorting and assembly machinery component 50 homolog [Tribolium castaneum] FS871738 ftes ...

  20. EST Table: FS858803 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS858803 E_FL_fner_08I05_R_0 10/09/28 95 %/113 aa ref|NP_001040212.1| sericotropin ...[Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/11 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fner ...

  1. EST Table: FS788843 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS788843 E_FL_fcaL_25O13_R_0 10/09/28 97 %/110 aa ref|NP_001040212.1| sericotropin ...[Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/09 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fcaL ...

  2. EST Table: FS779909 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS779909 E_FL_fcaL_32F20_R_0 10/09/28 96 %/113 aa ref|NP_001040212.1| sericotropin ...[Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/08 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fcaL ...

  3. EST Table: FS752443 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS752443 E_ET_caL-_09E02_R_0 10/09/28 98 %/111 aa ref|NP_001040212.1| sericotropin ...[Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/08 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 caL- ...

  4. EST Table: FS868425 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS868425 E_FL_fner_36N10_R_0 10/09/28 99 %/108 aa ref|NP_001040212.1| sericotropin ...[Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/11 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fner ...

  5. EST Table: FS863460 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS863460 E_FL_fner_22G20_R_0 10/09/28 100 %/105 aa ref|NP_001040212.1| sericotropin... [Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/11 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fner ...

  6. EST Table: FS761289 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS761289 E_FL_fcaL_17A17_F_0 10/09/28 92 %/113 aa ref|NP_001040212.1| sericotropin ...[Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/08 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS767530 fcaL ...

  7. EST Table: FS788550 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS788550 E_FL_fcaL_24P12_R_0 10/09/28 100 %/105 aa ref|NP_001040212.1| sericotropin... [Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/09 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fcaL ...

  8. EST Table: FS863591 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS863591 E_FL_fner_22N02_R_0 10/09/28 100 %/106 aa ref|NP_001040212.1| sericotropin... [Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/11 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fner ...

  9. EST Table: FS864691 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS864691 E_FL_fner_26A21_R_0 10/09/28 100 %/105 aa ref|NP_001040212.1| sericotropin... [Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/11 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fner ...

  10. EST Table: FS746333 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS746333 E_ET_caL-_05E14_F_0 10/09/28 100 %/112 aa ref|NP_001040212.1| sericotropin... [Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/08 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS767530 caL- ...

  11. EST Table: FS773654 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS773654 E_FL_fcaL_02C22_R_0 10/09/28 99 %/109 aa ref|NP_001040212.1| sericotropin ...[Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/08 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fcaL ...

  12. EST Table: FS863508 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS863508 E_FL_fner_22J03_R_0 10/09/28 100 %/105 aa ref|NP_001040212.1| sericotropin... [Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/11 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fner ...

  13. EST Table: FS861579 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS861579 E_FL_fner_16H12_R_0 10/09/28 100 %/111 aa ref|NP_001040212.1| sericotropin... [Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/11 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fner ...

  14. EST Table: FS856213 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS856213 E_FL_fner_01C08_R_0 10/09/28 91 %/117 aa ref|NP_001040212.1| sericotropin ...[Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/11 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS781882 fner ...

  15. EST Table: FS854903 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS854903 E_FL_fner_50H19_F_0 10/09/28 100 %/107 aa ref|NP_001040212.1| sericotropin... [Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/11 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS767530 fner ...

  16. EST Table: FS858637 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS858637 E_FL_fner_08A13_R_0 10/09/28 100 %/109 aa ref|NP_001040212.1| sericotropin... [Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/11 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fner ...

  17. EST Table: FS839906 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS839906 E_FL_fner_08A13_F_0 10/09/28 100 %/109 aa ref|NP_001040212.1| sericotropin... [Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/10 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS767530 fner ...

  18. EST Table: FS858076 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS858076 E_FL_fner_06G22_R_0 10/09/28 100 %/109 aa ref|NP_001040212.1| sericotropin... [Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/11 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fner ...

  19. EST Table: FS861022 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS861022 E_FL_fner_14O08_R_0 10/09/28 100 %/109 aa ref|NP_001040212.1| sericotropin... [Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/11 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fner ...

  20. EST Table: FS873205 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available FS873205 E_FL_fner_50H19_R_0 10/09/28 100 %/107 aa ref|NP_001040212.1| sericotropin... [Bombyx mori] gb|ABD36253.1| sericotropin [Bombyx mori] 10/09/11 n.h 10/08/29 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h FS784478 fner ...