WorldWideScience

Sample records for dye laser rods

  1. Tunable Microfluidic Dye Laser

    DEFF Research Database (Denmark)

    Olsen, Brian Bilenberg; Helbo, Bjarne; Kutter, Jörg Peter

    2003-01-01

    We present a tunable microfluidic dye laser fabricated in SU-8. The tunability is enabled by integrating a microfluidic diffusion mixer with an existing microfluidic dye laser design by Helbo et al. By controlling the relative flows in the mixer between a dye solution and a solvent......, the concentration of dye in the laser cavity can be adjusted, allowing the wavelength to be tuned. Wavelength tuning controlled by the dye concentration was demonstrated with macroscopic dye lasers already in 1971, but this principle only becomes practically applicable by the use of microfluidic mixing...

  2. Diode-pumped dye laser

    Science.gov (United States)

    Burdukova, O. A.; Gorbunkov, M. V.; Petukhov, V. A.; Semenov, M. A.

    2016-10-01

    This letter reports diode pumping for dye lasers. We offer a pulsed dye laser with an astigmatism-compensated three-mirror cavity and side pumping by blue laser diodes with 200 ns pulse duration. Eight dyes were tested. Four dyes provided a slope efficiency of more than 10% and the highest slope efficiency (18%) was obtained for laser dye Coumarin 540A in benzyl alcohol.

  3. Levitated droplet dye laser

    DEFF Research Database (Denmark)

    Azzouz, H.; Alkafadiji, L.; Balslev, Søren

    2006-01-01

    a high quality optical resonator. Our 750 nL lasing droplets consist of Rhodamine 6G dissolved in ethylene glycol, at a concentration of 0.02 M. The droplets are optically pumped at 532 nm light from a pulsed, frequency doubled Nd:YAG laser, and the dye laser emission is analyzed by a fixed grating...

  4. Microfluidic Dye Lasers

    DEFF Research Database (Denmark)

    Kristensen, Anders; Balslev, Søren; Gersborg-Hansen, Morten

    2006-01-01

    A technology for miniaturized, polymer based lasers, suitable for integration with planar waveguides and microfluidic networks is presented. The microfluidic dye laser device consists of a microfluidic channel with an embedded optical resonator. The devices are fabricated in a thin polymer film...

  5. Laser dye technology

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, P R

    1999-09-01

    The author has worked with laser dyes for a number of years. A first interest was in the Navy blue-green program where a flashlamp pumped dye laser was used as an underwater communication and detection device. It made use of the optical window of sea-water--blue for deep ocean, green for coastal water. A major activity however has been with the Atomic Vapor Laser Isotope Separation Program (AVLIS) at the Lawrence Livermore National Laboratory. The aim here has been enriching isotopes for the nuclear fuel cycle. The tunability of the dye laser is utilized to selectively excite one isotope in uranium vapor, and this isotope is collected electrostatically as shown in Figure 1. The interests in the AVLIS program have been in the near ultra-violet, violet, red and deep-red.

  6. Dye laser principles with applications

    CERN Document Server

    Duarte, Frank J; Liao, Peter F; Kelley, Paul

    1990-01-01

    A tutorial introduction to the field of dye lasers, Dye Laser Principles also serves as an up-to-date overview for those using dye lasers as research and industrial tools. A number of the issues discussed in this book are pertinent not only to dye lasers but also to lasers in general. Most of the chapters in the book contain problem sets that expand on the material covered in the chapter.Key Features* Dye lasers are among the most versatile and successful laser sources currently available in use Offering both pulsed and continuous-wave operation and tunable from the near ultraviole

  7. Azaquinolone dye lasers

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, P.R.; Atkins, R.L.; Henry, R.A.; Fletcher, A.N.

    1978-07-25

    The invention provides a dye laser comprising a lasing solution of a 7-substituted azaquinolone-2 in which the aza nitrogen occupies at least one of the 5, 6 and 8 ring positions. The 7-substituent is hydroxy, alkoxy, amino or substituted amino. Substituents may be attached to other ring positions. The present lasing compounds are aza analogs of corresponding quinolone compounds and, hence, are named ''azaquinolone'' compounds. The dye lasers lase in the blue to near ultraviolet region.

  8. Solid-state-laser-rod holder

    Science.gov (United States)

    Gettemy, D.J.; Barnes, N.P.; Griggs, J.E.

    1981-08-11

    The disclosure relates to a solid state laser rod holder comprising Invar, copper tubing, and epoxy joints. Materials and coefficients of expansion of the components of the holder combine with the rod to produce a joint which will give before the rod itself will. The rod may be lased at about 70 to 80/sup 0/K and returned from such a temperature to room temperature repeatedly without its or the holder's destruction.

  9. FY 1980 Report on Dye Laser Materials

    Science.gov (United States)

    1981-02-01

    by block number) Dye Lasers Laser Dyes Tunable Lasers Photodegradation Rhodamine Dyes 20. ABSTRACT (Continue n resld* it necesiry and Identify by block...limited usefulness as a portable military device because of the photodegradation of the dye solution. Although there have been state-of-the-art reviews...on laser dyes , 1𔃼 the photodegradation of laser dyes ,3 and dye lasers, 4- 6 only authors from, or funded by, military organizations have given strict

  10. Dye laser chain for laser isotope separation

    Science.gov (United States)

    Doizi, Denis; Jaraudias, Jean; Pochon, E.; Salvetat, G.

    1993-05-01

    Uranium enrichment by laser isotope separation uses a three step operation which requires four visible wavelengths to boost an individual U235 isotope from a low lying atomic energy level to an autoionizing state. The visible wavelengths are delivered by dye lasers pumped by copper vapor lasers (CVL). In this particular talk, a single dye chain consisting of a master oscillator and amplifier stages will be described and some of its performance given.

  11. Triplet losses in dye lasers

    Energy Technology Data Exchange (ETDEWEB)

    Baczynski, A.; Kossakowski, A.; Marszalek, T. (Uniwersytet Mikolaja Kopernika, Torun (Poland). Instytut Fizyki)

    1977-01-01

    The expression for losses due to triplet states in dye laser considered as a six-level system is given. It is shown that triplet losses depend on pumping parameters and photon number. Depending on molecular and cavity parameters two differe types of behavior of dye lasers are expected. Physical conditions are discussed in which triplet losses as well as photon number undergo a jump at the threshold.

  12. Flashlamp-pumped Ti:Sapphire laser with different rods grown by Czochralski and Verneuil methods

    Science.gov (United States)

    Boquillon, J. P.; Said, J.

    1992-04-01

    The design and the development of a flashlamp-pumped Ti:Sapphire laser is described. Design criteria are discussed and performance improvements using different types of fluorescent UV converters or filters, such as organic dyes or doped glass are presented. We have tested different laser rods at various Ti-concentrations obtained by Verneuil or Czochralski growth techniques. The maximum laser output energy of 540 mJ with a differential efficiency up to 1% was achieved by using only a pyrex filter surrounding the laser rod.

  13. Diffusion dynamics in microfluidic dye lasers

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Morten; Balslev, Søren; Mortensen, Niels Asger

    2007-01-01

    We have investigated the bleaching dynamics that occur in opto-fluidic dye lasers, where the liquid laser dye in a channel is locally bleached due to optical pumping. Our studies suggest that for micro-fluidic devices, the dye bleaching may be compensated through diffusion of dye molecules alone....... By relying on diffusion rather than convection to generate the necessary dye replenishment, our observation potentially allows for a significant simplification of opto-fluidic dye laser device layouts, omitting the need for cumbersome and costly external fluidic handling or on-chip micro-fluidic pumping...

  14. Tunable Optofluidic Third Order DFB Dye Laser

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Morten; Kristensen, Anders

    2007-01-01

    We present a low-threshold polymer-based nanofluidic dye laser. By employing a third order DFB laser resonator, we demonstrate a threshold fluence of ~7 muJ/mm2 and a tunability of 45 nm using a single laser dye......We present a low-threshold polymer-based nanofluidic dye laser. By employing a third order DFB laser resonator, we demonstrate a threshold fluence of ~7 muJ/mm2 and a tunability of 45 nm using a single laser dye...

  15. Laser dye toxicity, hazards, and recommended controls

    Energy Technology Data Exchange (ETDEWEB)

    Mosovsky, J.A.

    1983-05-06

    Laser dyes are complex fluorescent organic compounds which, when in solution with organic solvents, form a lasing medium. The wavelength of a dye laser's output beam can vary with different dyes, concentrations, and solvents, giving it a tunable feature capable of emitting ultraviolet, visible, or infrared radiation. Toxicity information on the approximately 100 commercially available laser dyes is very scarce. Limited animal experimentation has been performed with only a few dyes. This paper summarizes what is known about laser dye toxicity, and offers recommendations for controlling dye hazards. The laser dyes investigated have been categorized according to their central chemical structures. These include the xanthenes (rhodamines and fluoresceins), polymethines (cyanines and carbocyanines), coumarins, and stilbenes. A few other miscellaneous dyes that do not fall into one of these categories have also been investigated. Prepared laser dye solutions usually contain very small quantities of dye--typical dye concentrations are 10/sup -2/ to 10/sup -5/ molar. For this reason, the solvent in which the dye is dissolved plays an important role when defining potential hazards. Practically all the solvents used are flammable and toxic by inhalation and skin absorption, and therefore must be controlled properly.

  16. Zeolite-dye micro lasers

    CERN Document Server

    Vietze, U; Laeri, F; Ihlein, G; Schüth, F; Limburg, B; Abraham, M

    1998-01-01

    We present a new class of micro lasers based on nanoporous molecular sieve host-guest systems. Organic dye guest molecules of 1-Ethyl-4-(4-(p-Dimethylaminophenyl)-1,3-butadienyl)-pyridinium Perchlorat were inserted into the 0.73-nm-wide channel pores of a zeolite AlPO$_4$-5 host. The zeolitic micro crystal compounds where hydrothermally synthesized according to a particular host-guest chemical process. The dye molecules are found not only to be aligned along the host channel axis, but to be oriented as well. Single mode laser emission at 687 nm was obtained from a whispering gallery mode oscillating in a 8-$\\mu$m-diameter monolithic micro resonator, in which the field is confined by total internal reflection at the natural hexagonal boundaries inside the zeolitic microcrystals.

  17. Solvent-free fluidic organic dye lasers.

    Science.gov (United States)

    Choi, Eun Young; Mager, Loic; Cham, Tran Thi; Dorkenoo, Kokou D; Fort, Alain; Wu, Jeong Weon; Barsella, Alberto; Ribierre, Jean-Charles

    2013-05-06

    We report on the demonstration of liquid organic dye lasers based on 9-(2-ethylhexyl)carbazole (EHCz), so-called liquid carbazole, doped with green- and red-emitting laser dyes. Both waveguide and Fabry-Perot type microcavity fluidic organic dye lasers were prepared by capillary action under solvent-free conditions. Cascade Förster-type energy transfer processes from liquid carbazole to laser dyes were employed to achieve color-variable amplified spontaneous emission and lasing. Overall, this study provides the first step towards the development of solvent-free fluidic organic semiconducting lasers and demonstrates a new kind of optoelectronic applications for liquid organic semiconductors.

  18. 1983 Annual Report on Laser Dyes.

    Science.gov (United States)

    1984-04-01

    absorption at the lasing wavelength due to the accumula- tion of reaction products from the photodegradation of a laser dye is analyzed thioretically...Laser Dyes O by A. N. Fletcher Research DopetMrnt APRIL 1984 NAVAL WEAPONS CENTER CHINA LAKE, CALIFORNIA 93555 Appoved for ftc qesege dt"" ba n ftsd...work presented in seven open literature publications on laser dyes . This work originated within the Chemistry Division and was performed and/or

  19. Polymer dye lasers

    DEFF Research Database (Denmark)

    Balslev, Søren

    2006-01-01

    , elektronstrålelithografi og Röntgenstrålelithografi. Andre polymerer er også blevet formgivet via ”nanoimprint” lithografi for at skabe laserresonatorer. En række lasere, både baseret på et flydende forstærkningsmedium og et faststof forstærkningsrmedium er blevet udviklet. Laserne giver både lys i flere ”modes” og i een......Formålet med dette Ph.D. arbejde har været at udvikle miniaturiserede polymer farvestoflasere, egnet til at blive integreret i mikrochips som også indeholder andre polymerstrukturer – som for eksempel kan findes i ”Laboratorie-på-en-chip” kredsløb. Lasernes funktion skal være at levere lys til...... meget følsomme sensorformål, og at undgå at skulle opliniere eksterne lyskilder til sensorer på polymerchips. En enkelt type gennemsigtig ”resist” (SU-8) er blevet brugt til at udvikle en række laserresonatorer i polymer. ”Resisten” er blevet formgivet via en række lithografiske teknikker: UV lithografi...

  20. Two-photon pumped cavity lasing in novel dye doped bulk matrix rods

    Science.gov (United States)

    He, Guang S.; Zhao, Chan F.; Bhawalkar, Jayant D.; Prasad, Paras N.

    1995-12-01

    Trans-4-[p-(N-ethyl-N-hydroxyethylamino)styryl]-N-methylpyridi that possesses a much greater two-photon absorption cross section and much stronger upconversion fluorescence emission than common organic dyes (such as rhodamine), when excited with near infrared laser radiation. Utilizing ASPT doped bulk polymer rods, two-photon pumped frequency upconverted cavity lasing has been accomplished using a Q-switched Nd:YAG laser as the pump source. The wavelength and pulse duration were ˜600 nm and 3-6 ns, respectively, for the cavity lasing; whereas the corresponding values for pump pulses were 1.06 μm and ˜10 ns, respectively. For a 7 mm long sample rod with a dopant concentration d0=8×10-3 M/L, the conversion efficiency from the absorbed pump energy to the cavity lasing output was ˜3.5% at a pump energy level of 1.3 mJ. The lasing lifetime, in terms of pulse numbers, was more than 4×104 pulses at 2 Hz repetition rate and room temperature.

  1. Laser dye stability. Pt. 3. Bicyclic dyes in ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, A.N. (Naval Weapons Center, China Lake, Calif. (USA). Research Dept.)

    1977-11-01

    A commercial coaxial xenon flashlamp has been used to evaluate the stability of a variety of coumarin and quinolone laser dyes. The lasing characteristics of over 30 dyes have been quantitatively evaluated as a function of the total excitation energy to which recirculating dye solution has been exposed. Degradation constants were determined an an evaluation was made of the effects of functional group variation upon the stability of the dyes. Comparison with the data of other workers revealed that exclusion of excitation energy below 220 nm does not change the stability of 4-methyl coumarins, but can increase the stability of other coumarins as much as 50 fold.

  2. Tunability of optofluidic distributed feedback dye lasers

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Morten; Kristensen, Anders

    2007-01-01

    We investigate the tunability of optofluidic distributed feedback (DFB) dye lasers. The lasers rely on light-confinement in a nano-structured polymer film where an array of nanofluidic channels constitutes a third order Bragg grating DFB laser resonator with a central phase-shift. The lasers...... are operated by filling the DFB laser resonator with a dye solution by capillary action and optical pumping with a frequency doubled Nd: YAG laser. The low reflection order of the DFB laser resonator yields low out-of-plane scattering losses as well as a large free spectral range (FSR), and low threshold...

  3. Dye lasers. Citations from the NTIS data base

    Science.gov (United States)

    Cavagnaro, D. M.

    1980-08-01

    Studies on dye laser theory, design, components, optical systems, and frequency range are presented in approximately 96 citations. Abstracts on lasing dyes, pumping, tuning, excitation, molecular structure, and modulation are included. Studies on dye laser use in spectroscopy are covered.

  4. Nanoimprinted polymer photonic crystal dye lasers

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Smith, Cameron; Buss, Thomas

    2010-01-01

    Optically pumped polymer photonic crystal band-edge dye lasers are presented. The photonic crystal is a rectangular lattice providing laser feedback as well as an optical resonance for the pump light. The lasers are defined in a thin film of photodefinable Ormocore hybrid polymer, doped...... with the laser dye Pyrromethene 597. A compact frequency doubled Nd:YAG laser (352 nm, 5 ns pulses) is used to pump the lasers from above the chip. The laser devices are 450 nm thick slab waveguides with a rectangular lattice of 100 nm deep air holes imprinted into the surface. The 2-dimensional rectangular...... lattice is described by two orthogonal unit vectors of length a and b, defining the P and X directions. The frequency of the laser can be tuned via the lattice constant a (187 nm - 215 nm) while pump light is resonantly coupled into the laser from an angle () depending on the lattice constant b (355 nm...

  5. Liquid crystal tunable photonic crystal dye laser

    DEFF Research Database (Denmark)

    Buss, Thomas; Christiansen, Mads Brøkner; Smith, Cameron

    2010-01-01

    We present a dye-doped liquid crystal laser using a photonic crystal cavity. An applied electric field to the liquid crystal provides wavelength tunability. The photonic crystal enhances resonant interaction with the gain medium....

  6. On-chip tunable optofluidic dye laser

    Science.gov (United States)

    Cai, Zengyan; Shen, Zhenhua; Liu, Haigang; Yue, Huan; Zou, Yun; Chen, Xianfeng

    2016-11-01

    We demonstrate a chip-scale tunable optofluidic dye laser with Au-coated fibers as microcavity. The chip is fabricated by soft lithography. When the active region is pumped, a relatively low threshold of 6.7 μJ/mm2 is realized with multimode emission due to good confinement of the cavity mirrors, long active region, as well as total reflectivity. It is easy to tune the lasing emission wavelength by changing the solvent of laser dye. In addition, the various intensity ratios of multicolor lasing can be achieved by controlling flow rates of two fluid streams carried with different dye molecules. Furthermore, the convenience in fabrication and directional lasing emission outcoupled by the fiber make the tunable optofluidic dye laser a promising underlying coherent light source in the integrated optofluidic systems.

  7. Bleaching and diffusion dynamics in optofluidic dye lasers

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Morten; Balslev, Søren; Mortensen, Asger

    2007-01-01

    The authors have investigated the bleaching dynamics that occur in optofluidic dye lasers where the liquid laser dye in a microfluidic channel is locally bleached due to optical pumping. They find that for microfluidic devices, the dye bleaching may be compensated through diffusion of dye molecules...... pumping devices. ©2007 American Institute of Physics....

  8. Optofluidic third order distributed feedback dye laser

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Morten; Kristensen, Anders

    2006-01-01

    This letter describes the design and operation of a polymer-based third order distributed feedback (DFB) microfluidic dye laser. The device relies on light confinement in a nanostructured polymer film where an array of nanofluidic channels is filled by capillary action with a liquid dye solution...... which has a refractive index lower than that of the polymer. In combination with a third order DFB grating, formed by the array of nanofluidic channels, this yields a low threshold for lasing. The laser is straightforward to integrate on lab-on-a-chip microsystems where coherent, tunable light...

  9. Cladding For Transversely-Pumped Laser Rod

    Science.gov (United States)

    Byer, Robert L.; Fan, Tso Yee

    1989-01-01

    Combination of suitable dimensioning and cladding of neodymium:yttrium aluminum garnet of similar solid-state laser provides for more efficient utilization of transversely-incident pump light from diode lasers. New design overcomes some of limitations of longitudinal- and older transverse-pumping concepts and promotes operation at higher output powers in TEM00 mode.

  10. Micro-Cavity Fluidic Dye Laser

    DEFF Research Database (Denmark)

    Helbo, Bjarne; Kristensen, Anders; Menon, Aric Kumaran

    2003-01-01

    We have successfully designed, fabricated and characterized a micro-cavity fluidic dye laser with metallic mirrors, which can be integrated with polymer based lab-on-a-chip microsystems without further processing steps. A simple rate-equation model is used to predict the average pumping power...

  11. Optofluidic dye laser in a foil

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Christiansen, Mads Brøkner; Mappes, Timo;

    2010-01-01

    First order distributed feedback optofluidic dye lasers embedded in a 350 mu m thick TOPAS (R) foil are demonstrated. They are designed in order to give high output pulse energies. Microfluidic channels and first order distributed feedback gratings are fabricated in parallel by thermal nanoimprin...

  12. Diode-pumped tunable laser with dual Cri:LiSAF rods

    Institute of Scientific and Technical Information of China (English)

    Xie Guo-Qiang; Wang Tao; Zhu He-Yuan; Qian Lie-Jia

    2006-01-01

    We propose and demonstrate a simple approach to lower the thermal quenching effect and improve the output power of Cr:LiSAF lasers, which is accomplished by employing two laser rods. The resonator contains two laser rods and is designed by using two "X" folding cavities in cascade. A tunable laser output of ~ 180 mW has been achieved with the pump of single-striped laser diodes. Compared with lasers using single gain rod, the laser with dual rods shows less severe thermal effect and increases the output by more than two times.

  13. Dye-enhanced laser tissue welding.

    Science.gov (United States)

    Chuck, R S; Oz, M C; Delohery, T M; Johnson, J P; Bass, L S; Nowygrod, R; Treat, M R

    1989-01-01

    For vascular anastomosis, use of topical photosensitizing dye enhances selective delivery of laser energy to target tissue, thus reducing the amount of collateral thermal injury and threshold power required for welding. For fluorescein isothiocyanate (FITC)--stained rabbit aorta in vitro, the threshold for tissue blanching was 15 seconds of 100 mW exposure of cw argon ion laser compared with 15 seconds at 300 mW for unstained tissue. The threshold power density needed for argon laser welding of abdominal aortotomies in rabbits in vivo was 3.8 W/cm2 with FITC and 7.6 W/cm2 without the dye. However, bursting pressures for the two groups (164 mm Hg with FITC, 147 mm Hg without FITC) were not significantly different. Histology revealed decreased collateral thermal damage in FITC-enhanced welds. Use of photosensitizing dyes for tissue welding is feasible and may allow arterial welding with lower power laser systems and cause less thermal trauma by lowering threshold power levels.

  14. Novel Tunable Dye Laser for Lidar Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A tunable dye laser for Lidar detection will be fabricated based on the innovative dye-doped Holographic Polymer Dispersed Liquid Crystals (HPDLC) technology. The...

  15. Solid state microcavity dye lasers fabricated by nanoimprint lithography

    DEFF Research Database (Denmark)

    Nilsson, Daniel; Nielsen, Theodor; Kristensen, Anders

    2004-01-01

    We present a solid state polymer microcavity dye laser, fabricated by thermal nanoimprint lithography (NIL) in a dye-doped thermoplast. The thermoplast poly-methylmethacrylate (PMMA) is used due to its high transparency in the visible range and its robustness to laser radiation. The laser dye...... propagating TE–TM modes. The laser cavity has the lateral shape of a trapezoid, supporting lasing modes by reflection on the vertical cavity walls. The solid polymer dye lasers emit laterally through one of the vertical cavity walls, when pumped optically through the top surface by means of a frequency...

  16. Tunable lasers for waste management photochemistry applications. [Dye lasers, excimer lasers, IR lasers

    Energy Technology Data Exchange (ETDEWEB)

    Finch, F.T. (comp.)

    1978-09-01

    A review of lasers with potential photochemical applications in waste management indicates that dye lasers, as a class, can provide tunable laser output through the visible and near-uv regions of the spectrum of most interest to photochemistry. Many variables can affect the performance of a specific dye laser, and the interactions of these variables, at the current state of the art, are complex. The recent literature on dye-laser characteristics has been reviewed and summarized, with emphasis on those parameters that most likely will affect the scaling of dye lasers in photochemical applications. Current costs are reviewed and correlated with output power. A new class of efficient uv lasers that appear to be scalable in both energy output and pulse rate, based on rare-gas halide excimers and similar molecules, is certain to find major applications in photochemistry. Because the most important developments are too recent to be adequately described in the literature or are the likely outcome of current experiments, the basic physics underlying the class of excimer lasers is described. Specific cost data are unavailable, but these new gas lasers should reflect costs similar to those of existing gas lasers, in particular, the pulsed CO/sub 2/ lasers. To complete the survey of tunable-laser characteristics, the technical characteristics of the various classes of lasers in the ir are summarized. Important developments in ir laser technology are being accelerated by isotope-separation research, but, initially at least, this portion of the spectrum is least likely to receive emphasis in waste-management-oriented photochemistry.

  17. Laser sclerostomy by pulsed-dye laser and goniolens

    Energy Technology Data Exchange (ETDEWEB)

    Latina, M.A.; Dobrogowski, M.; March, W.F.; Birngruber, R. (Massachusetts General Hospital, Boston (USA))

    1990-12-01

    We describe an ab-interno laser sclerostomy procedure using the method termed dye-enhanced ablation with a slit-lamp delivery system and special goniolens such that only the laser light beam penetrates the anterior chamber. The procedure uses a microsecond-pulsed-dye laser emitting at 666 nm and iontophoresis of methylene blue dye (absorption of 668 nm) into the sclera at the limbus to enhance the absorption of the laser light. We compared the number of pulses needed to perforate excised human sclera at pulse durations of 1.5, 20, and 300 microseconds. Pulse durations of 1.5 and 20 microseconds required 20 pulses or fewer to perforate excised human sclera with pulse energies of 75 to 100 mJ. The ab-interno laser sclerostomy procedure was performed in 54 eyes of Dutch-belted rabbits with pulse durations of 1.5 or 20 microseconds and a 100- or 200-microns incident spot diameter delivered using a CGF goniolens. Full-thickness fistulas were successfully created at both pulse durations in approximately 80% of eyes treated. A range of three to 25 pulses was required to perforate sclera with slightly fewer pulses and lower pulse energies at 1.5 microseconds compared with 20 microseconds. There were no significant complications from the procedure. This technique could permit filtration surgery to be performed on an outpatient basis.

  18. Dye Photodestruction in a Solid-State Dye Laser with a Polymeric Gain Medium

    Science.gov (United States)

    Popov, Sergei

    1998-09-01

    The process of dye photodestruction in a solid-state dye laser is studied, and implemented is a polymeric gain medium doped with a strongly concentrated dye. The behavior of the conversion efficiency in the polymeric gain medium pumped with different laser-pulse repetition rates and the process of dye photobleaching are analyzed. The contribution of the heating of the host material into the dye molecules deactivation is discussed. The negative effect of high dye concentration on the dye stability under a high pump repetition rate is reported and analyzed for the first time to my knowledge. A comparison of the present results with recently published data demonstrates the major role of photodestruction, rather than direct thermodestruction, in the dye stability of the solid-state gain medium. The role of additives with low molecular weights in the polymeric matrix, for increasing the stability of the gain material, is discussed.

  19. Bimanes and Related Heterocycles as Laser Dyes

    Science.gov (United States)

    1991-01-10

    514 ones) as laser dyes. Kosower introduced a system nm. Presumably helicity, that was demonstrated by of trivial nomenclature for the bimanes based...Variation in substitution patterns in syn-bimanes tion (S-S) and triplet-triplet (T-T) spectral regions, has remained limited. In the Kosower scheme for...1. R. Politzer, [22] E. M. Kosower , D. Faust, M. Ben-Shoshan, 1. Gold- C. M. Lau, J. AppI. Phys., 62, 1987, 36; (c) T. G. Pavlo- berg, 1. Org. Chem

  20. Continuous-wave organic dye lasers and methods

    Science.gov (United States)

    Shapira, Ofer; Chua, Song-Liang; Zhen, Bo; Lee, Jeongwon; Soljacic, Marin

    2014-09-16

    An organic dye laser produces a continuous-wave (cw) output without any moving parts (e.g., without using flowing dye streams or spinning discs of solid-state dye media to prevent photobleaching) and with a pump beam that is stationary with respect to the organic dye medium. The laser's resonant cavity, organic dye medium, and pump beam are configured to excite a lasing transition over a time scale longer than the associated decay lifetimes in the organic dye medium without photobleaching the organic dye medium. Because the organic dye medium does not photobleach when operating in this manner, it may be pumped continuously so as to emit a cw output beam. In some examples, operation in this manner lowers the lasing threshold (e.g., to only a few Watts per square centimeter), thereby facilitating electrical pumping for cw operation.

  1. Enhancement of polymer dye lasers by multifunctional photonic crystal lattice

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Xiao, Sanshui; Mortensen, Asger

    2009-01-01

    The light output of dye doped hybrid polymer band-edge lasers is increased more than 100 times by using a rectangular lattice photonic crystal, which provides both feedback and couples more pump light into the laser.......The light output of dye doped hybrid polymer band-edge lasers is increased more than 100 times by using a rectangular lattice photonic crystal, which provides both feedback and couples more pump light into the laser....

  2. Dye laser as a six-level system

    Energy Technology Data Exchange (ETDEWEB)

    Baczynski, A.; Kossakowski, A.; Marszalek, T.

    1977-01-01

    Stationary solutions of kinetic equations of dye lasers based on a six-level model of dye molecule were analyzed. Such a model is the simplest one to account for the participation of triplet states in generating a laser. The course of triplet losses versus pumping parameter can undergo a jump at threshold which leads to the jump of photon number in the cavity. The improvement of the laser performance of dye lasers by means of an additional triplet-triplet pumping is proposed.

  3. Laser dye stability. Pt. 4. Photodegradation relationships for bicyclic dyes in alcohol solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, A.N. (Naval Weapons Center, China Lake, Calif. (USA). Research Dept.)

    1978-05-01

    Changes in the absorption of a dye laser solution are examined after excitation with a xenon flashlamp. It is found that the rate of bleaching as a function of the total input energy of coumarin or quinolone dyes in ethanol increases in direct proportion to the dye concentration. This relationship suggests that the dye reacts with a photoproduct of the solvent rather than being directly decomposed by the xenon flash. We have measured the conversion of the dye to form products, P, absorbing at the lasing wavelength. Results correspond to the dye reacting with a precursor of P to form either insoluble products or ones not absorbing at the lasing wavelength. Thus larger total amounts of bleached dye do not proportionately increase P, and hence do not proportionately inhibit lasing. Furthermore, we find that P increases with the total input energy fairly independent of the rate of bleaching for a given bicyclic dye in an alcohol solution.

  4. Two dye combinations suitable for two-color/two-dye laser-induced fluorescence thermography for ethanol

    Science.gov (United States)

    Fenner, Andreas; Stephan, Peter

    2017-06-01

    This paper presents two dye combinations suitable for two-color/two-dye laser-induced fluorescence thermography for ethanol. Besides the temperature dependency of the fluorescence, the influences of laser fluence, dye concentration, pressure, dissolved air, and photobleaching are also discussed. The experimental data are compared with models and data available in literature. Based on this, parameter ranges for two-color/two-dye laser-induced fluorescence thermography applications can be determined.

  5. STRONGLY COLORED NOISE IN THE DYE LASER FAR ABOVE THRESHOLD

    Institute of Scientific and Technical Information of China (English)

    朱士群

    1991-01-01

    The intensity fluctuations of a single mode ,dye laser is investigated when the laser is operated far above threshold.The analytic result of the laser intensity correlation function is obtained when both the additive white and strongly multiplicative colored noise are included in the laser model .The analyses show clearly the dependence of the intensity fluctuations on the strength and time scale of the pump noise.

  6. Millijoule Pulse Energy Second Harmonic Generation With Single-Stage Photonic Bandgap Rod Fiber Laser

    DEFF Research Database (Denmark)

    Laurila, Marko; Saby, Julien; Alkeskjold, Thomas Tanggaard

    2011-01-01

    In this paper, we demonstrate, for the first time, a single-stage Q-switched single-mode (SM) ytterbium-doped rod fiber laser delivering record breaking pulse energies at visible and UV light. We use a photonic bandgap rod fiber with a mode field diameter of 59μm based on a new distributed...

  7. Multilayer Slab Waveguide Distributed Feedback Dye Laser Sensors

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Smith, Cameron; Leung, M.

    2013-01-01

    Organic dye-based distributed feedback (DFB) lasers are widely tunable laser light sources in the visible wavelength range and exhibit low-cost, simple fabrication, low threshold and single-mode emission [1]. Precise emission wavelength modeling is essential for understanding and optimization of ...

  8. Investigation of the dye concentration influence on the lasing wavelength and threshold for a micro-fluidic dye laser

    DEFF Research Database (Denmark)

    Helbo, Bjarne; Kragh, Søren; Kjeldsen, B.G.;

    2003-01-01

    We investigate a micro-fluidic dye laser, which can be integrated with polymer-based lab-on-a-chip microsystems without further processing steps. A simple rate-equation model is used to predict the lasing threshold. The laser device is characterised using the laser dye Rhodamine 6G dissolved in e...

  9. Laser-induced fluorescence and optical reflection spectra of Japanese natural dyes on silk

    OpenAIRE

    Miyoshi, Tadaki; Matsuda, Yasunori

    1987-01-01

    Fluorescence spectra under nitrogen-laser excitation were measured for silk cloth dyed with Japanese natural dyes. An identification of the dyes on silk was carried out using a laser-induced fluorescence (LIF) technique since dyed cloth has a characteristic fluorescence spectra. Moreover, it is possible to identify dyes on faded cloth and on cloth prepared by a combination dyeing using two kinds of dyes. The LIF technique can identify dyes on cloth which is difficult to identify using the ref...

  10. A Coupled Cavity Micro Fluidic Dye Ring Laser

    CERN Document Server

    Gersborg-Hansen, M; Mortensen, N A; Kristensen, A

    2004-01-01

    We present a laterally emitting, coupled cavity micro fluidic dye ring laser, suitable for integration into lab-on-a-chip micro systems. The micro-fluidic laser has been successfully designed, fabricated, characterized and modelled. The resonator is formed by a micro-fluidic channel bounded by two isosceles triangle mirrors. The micro-fluidic laser structure is defined using photo lithography in 10 microns thick SU-8 polymer on a glass substrate. The micro fluidic channel is sealed by a glass lid, using PMMA adhesive bonding. The laser is characterized using the laser dye Rhodamine 6G dissolved in ethanol or ethylene glycol as the active gain medium, which is pumped through the micro-fluidic channel and laser resonator. The dye laser is optically pumped normal to the chip plane at 532 nm by a pulsed, frequency doubled Nd:YAG laser and lasing is observed with a threshold pump pulse energy flux of around 55 micro-Joule/square-milimeter. The lasing is multi-mode, and the laser has switchable output coupling into...

  11. High repetition rate femtosecond dye amplifier using a laser diode pumped neodymium:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Zysset, B.; LaGasse, M.J.; Fujimoto, J.G.; Kafka, J.D.

    1989-02-06

    A high repetition rate femtosecond dye amplifier is demonstrated using a laser diode pumped Q-switched Nd:YAG laser. Amplification of wavelength tunable 300 fs pulses from a synchronously mode-locked rhodamine dye laser is achieved with a saturated gain of 70 and a small gain of 200 at a repetition rate of 800 Hz. Maximum pulse energies of 40 nJ are obtained, and pulse compression to as short as 30 fs is demonstrated.

  12. High repetition rate femtosecond dye amplifier using a laser diode pumped neodymium:YAG laser

    Science.gov (United States)

    Zysset, B.; LaGasse, M. J.; Fujimoto, J. G.; Kafka, J. D.

    1989-02-01

    A high repetition rate femtosecond dye amplifier is demonstrated using a laser diode pumped Q-switched Nd:YAG laser. Amplification of wavelength tunable 300 fs pulses from a synchronously mode-locked rhodamine dye laser is achieved with a saturated gain of 70 and a small gain of 200 at a repetition rate of 800 Hz. Maximum pulse energies of 40 nJ are obtained, and pulse compression to as short as 30 fs is demonstrated.

  13. Mode coupling in organic dye lasers

    Energy Technology Data Exchange (ETDEWEB)

    Hirth, A.

    1973-10-25

    Saturable dye triggering is discussed together with relaxation time and pulse duration. The influence of stimulated emission is detailed. Experimental results of mode coupling with cyanines and xanthines, flash excited and not, are reported.

  14. Technical Development of the Small Fission Gas Measurement in Fuel Rods using the Laser Puncturing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Heemoon; Baik, Seungje; Jin, Younggwan; Jung, Yanghong; Yoo, Boungok; Ahn, Sangbok; Yang, Yongsik; Lee, Byoungoon

    2013-12-15

    Information of fuel cladding tube and expected gas amount were obtained from fuel development department to design chamber volume and specification of laser device. Laser puncturing tests for several tubes were performed to setup power and capability. Laser puncturing tests for several tubes were performed to setup power and capability. Vacuum system with chamber was established. Additionally, QMS(Quadruple Mass Spectrometer in high vacuum state) was installed in vacuum system. The system was installed in hotcell following the preliminary test for the puncturing, pressure measuring and gas content analysis. After system test was installed in hotcell following the preliminary test for the puncturing, pressure measuring and gas content analysis. After system test was completed, SFR fuel rods were punctured to measure total gas amount and each gas content(He, Xe, Kr). The system for laser puncturing and measurement of small fission gas amout in fuel rod was designed with considering hotcell facility and fuel rod condition for first year. Chamber size, laser capability were well operated and the system showed reasonable results. In second year, QMS(Quadruple Mass Spectrometer) was installed in the system for quantitative analysis of gas contents. Thus, Laser puncturing, amount of gas measurement and gas analysis were carried out in one time. The system was activated for SFR fuel rods after installation and preliminary test. 9 SFR fuel rods were tested and produced total gas amounts and gas analysis data(He, Xe, Kr)

  15. Physics and technology of tunable pulsed single longitudinal mode dye laser

    Indian Academy of Sciences (India)

    G Sridhar; V S Rawat; Nitin Kawade; Sunita Singh; L M Gantayet

    2010-11-01

    Design and technology demonstration of compact, narrow bandwidth, high repetition rate, tunable SLM dye lasers in two different configurations, namely Littrow and grazing incidence grating (GIG), were carried out in our lab at BARC, India. The single longitudinal mode (SLM) dye laser generates single-mode laser beams of ∼ 400 MHz (GIG configuration) and ∼ 600 MHz (Littrow configuration) bandwidth. Detailed performance studies of the Littrow and GIG dye laser resonators showed that GIG dye laser results in narrower linewidth and broad mode hop free wavelength scanning over 70 GHz. In this paper we present experimental studies carried out on the high repetition rate SLM dye laser system.

  16. Laser dyes excited by high PRR Nd:YAG laser second-harmonic radiation

    Science.gov (United States)

    Soldatov, A. N.; Donin, V. I.; Jakovin, D. V.; Reimer, I. V.

    2008-01-01

    The lasing characteristics of red-emitting dyes in ethanol excited by Nd:YAG laser second-harmonic radiation are examined. The Nd:YAG laser was pumped by a diode matrix. The pump pulse repetition rates (PRRs) were 2.5 - 10 kHz and the pulse duration was 60 - 300 ns. The following dyes were evaluated: oxazine 17, DCM, DCM sp, and pyridine 1. The conversion efficiency for oxazine was 25 % without wavelength selection and 15 % with wavelength selection over the tuning range from 630 to 700 nm. The Nd:YAG and dye laser designs used are described elsewhere [1,2].

  17. PM567-Doped solid dye lasers based on PMMA

    Institute of Scientific and Technical Information of China (English)

    Li Xiao-Hui; Fan Rong-Wei; Xia Yuan-Qin; Liu Wei; Chen De-Ying

    2007-01-01

    Polymers are a kind of attractive hosts for laser dyes due to their high transparency in both pumping and lasing ranges and superior optical homogeneity. In this paper solid dye samples based on polymethyl methacrylate (PMMA)doped with different concentrations of 1, 3, 5, 7, 8 -pentamethyl-2, 6-diethylpyrromethene-BF2 (PM567) are prepaed.The absorption, fluorescence and lasing spectra of the samples are obtained. Wide absorption and fluorescence bands are obtained and a red shift of the maxima of the lasing emission spectra is observed. With the second-harmonic generation of Q-switched Nd:YAG laser (532 nm, ~20 ns) pumping the samples longitudinally, the slope efficiencies of the samples are obtained. There is an optimal dye concentration for the highest slope efficiency when the pumping energy is lower than some typical value (~250 m J), and the highest slope efficiency 35.6% is obtained in the sample with a dye concentration of 2 × 10-4 mol/L. Pumping the samples at a rate of 10Hz with a pulse energy as high as 200 mJ (the fluence is 0.2J/cm2), the output energy drops to one-half of its initial value after approximate 15500 pulses and the normalized photostability is 5.17GJ/mol. A kind of solid dye laser which could have some applications is built.

  18. Low-cost Engineering of Laser Rods and Slabs with Liquid Phase Epitaxy

    Science.gov (United States)

    2011-09-01

    the rod taken with a digital camera and electronic flash . .............................8 Figure 12. Projection image of the LPE rod taken with...light from the flash lamp. Parasitic whispering gallery modes (WGM) at the laser wavelength arose due to total internal reflection (1). For the last...was measured by collecting some of the diffuse reflection from a 2-mm-thick sheet of sintered teflon (18) placed in the cavity, with a hole to pass

  19. Dye-sensitized solar cells using laser processing techniques

    Science.gov (United States)

    Kim, Heungsoo; Pique, Alberto; Kushto, Gary P.; Auyeung, Raymond C. Y.; Lee, S. H.; Arnold, Craig B.; Kafafi, Zakia H.

    2004-07-01

    Laser processing techniques, such as laser direct-write (LDW) and laser sintering, have been used to deposit mesoporous nanocrystalline TiO2 (nc-TiO2) films for use in dye-sensitized solar cells. LDW enables the fabrication of conformal structures containing metals, ceramics, polymers and composites on rigid and flexible substrates without the use of masks or additional patterning techniques. The transferred material maintains a porous, high surface area structure that is ideally suited for dye-sensitized solar cells. In this experiment, a pulsed UV laser (355nm) is used to forward transfer a paste of commercial TiO2 nanopowder (P25) onto transparent conducting electrodes on flexible polyethyleneterephthalate (PET) and rigid glass substrates. For the cells based on flexible PET substrates, the transferred TiO2 layers were sintered using an in-situ laser to improve electron paths without damaging PET substrates. In this paper, we demonstrate the use of laser processing techniques to produce nc-TiO2 films (~10 μm thickness) on glass for use in dye-sensitized solar cells (Voc = 690 mV, Jsc = 8.7 mA/cm2, ff = 0.67, η = 4.0 % at 100 mW/cm2). This work was supported by the Office of Naval Research.

  20. In liquid laser treated graphene oxide for dye removal

    Energy Technology Data Exchange (ETDEWEB)

    Russo, Paola, E-mail: rsspla1@gmail.com [Dipartimento di Scienze Chimiche, Universita’ degli Studi di Catania, Viale Andrea Doria 6, Catania 95125 (Italy); Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave., West Waterloo, Ontario N2L 3G1 (Canada); D’Urso, Luisa [Dipartimento di Scienze Chimiche, Universita’ degli Studi di Catania, Viale Andrea Doria 6, Catania 95125 (Italy); Hu, Anming [Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN 57996-2210 (United States); Zhou, Norman [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave., West Waterloo, Ontario N2L 3G1 (Canada); Compagnini, Giuseppe [Dipartimento di Scienze Chimiche, Universita’ degli Studi di Catania, Viale Andrea Doria 6, Catania 95125 (Italy)

    2015-09-01

    Highlights: • Graphene oxide and reduced graphene oxide were tested as adsorbents for dye removal from water. • Reduced graphene oxide was obtained after laser irradiation of a colloidal suspension of graphene oxide. • Methylene blue was chosen as the dye to test graphene oxide and reduced graphene oxide. - Abstract: The presence of dyes, pharmaceuticals and many other pollutants in wastewaters is critical due to severe effects on the human beings and on the environment. Here, solutions of graphene oxide (GO) and reduced graphene oxide (rGO) were tested as adsorbents for the removal of methylene blue (MB), a cationic dye, from aqueous media. The reduced forms of graphene oxide were obtained after laser irradiation of colloidal suspensions of graphene oxide, obtained by the Hummers and Offeman's method. We observed that both graphene oxide and its reduced forms are excellent adsorbents towards methylene blue. In particular, rGO showed a higher adsorption capacity than GO, suggesting that a strict control of laser irradiation time permits to obtain rGO with different degrees of reduction and therefore the residual oxygenated functional groups may influence the adsorption behaviour more or less. Characterization of the samples by atomic force microscopy (AFM) showed that produced rGO sheets via laser irradiation exhibited a discontinuous surface where some holes could be detected contributing to an enhancement of the rGO surface area that is a higher adsorption capacity.

  1. Polymer photonic crystal dye lasers as optofluidic cell sensors

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Lopacinska, Joanna M.; Jakobsen, Mogens Havsteen;

    2009-01-01

    Dye doped hybrid polymer lasers are implemented as label free evanescent field biosensors for detection of cells. It is demonstrated that although the coverage is irregular and the cells extend over several lattice constants, the emission wavelength depends linearly on the fraction of the surface...... covered by the HeLa cells used as model system. Design parameters relating to photonic crystal sensing of large objects are identified and discussed. The lasers are chemically modified to bind cells and molecules with flexible UV activated linker molecules.......Dye doped hybrid polymer lasers are implemented as label free evanescent field biosensors for detection of cells. It is demonstrated that although the coverage is irregular and the cells extend over several lattice constants, the emission wavelength depends linearly on the fraction of the surface...

  2. Self-healing organic-dye-based random lasers

    CERN Document Server

    Anderson, Benjamin R; Eilers, Hergen

    2015-01-01

    One of the primary difficulties in the implementation of organic-dye-based random lasers is the tendency of organic dyes to irreversibly photodecay. In this letter we report the observation of "reversible" photodegradation in a Rhodamine 6G and ZrO$_2$ nanoparticle doped polyurethane random laser. We find that during degradation the emission broadens, redshifts, and decreases in intensity. After degradation the system is observed to self-heal leading to the emission returning to its pristine intensity, giving a recovery efficiency of 100%. While the peak intensity fully recovers, the process is not strictly "reversible" as the emission after recovery is still found to be broadened and redshifted. The combination of the peak emission fully recovering and the broadening of the emission leads to a remarkable result: the random laser cycled through degradation and recovery has a greater integrated emission intensity than the pristine system.

  3. Single mode dye-doped polymer photonic crystal lasers

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Buss, Thomas; Smith, Cameron

    2010-01-01

    Dye-doped polymer photonic crystal (PhC) lasers fabricated by combined nanoimprint and photolithography are studied for their reproducibility and stability characteristics. We introduce a phase shift in the PhC lattice that substantially improves the yield of single wavelength emission. Single mode...... emission and reproducibility of laser characteristics are important if the lasers are to be mass produced in, e. g., optofluidic sensor chips. The fabrication yield is above 85% with highly reproducible wavelengths (within 0.5%), and the temperature dependence on the wavelength is found to be -0.045 or -0...

  4. TEM00 mode Nd:YAG solar laser by side-pumping a grooved rod

    Science.gov (United States)

    Vistas, Cláudia R.; Liang, Dawei; Almeida, Joana; Guillot, Emmanuel

    2016-05-01

    A simple TEM00 mode solar laser system with a grooved Nd:YAG rod pumped through a heliostat-parabolic mirror system is reported here. The radiation coupling capacity of a fused silica tube lens was combined with the multipass pumping ability of a 2 V-shaped cavity to provide efficient side-pumping along a 4.0 mm diameter grooved Nd:YAG single-crystal rod. TEM00 mode solar laser power of 3.4 W was measured by adopting an asymmetric large-mode laser resonant cavity. Record TEM00 mode solar laser collection efficiency of 3.4 W/m2and slope efficiency of 1.9% was achieved, which corresponds to 1.8 and 2.4 times more than the previous TEM00 mode Nd:YAG solar laser using the PROMES-CNRS heliostat-parabolic mirror system, respectively.

  5. Solid-state polymeric dye lasers

    CERN Document Server

    Singh, S; Sridhar, G; Muthuswamy, V; Raja, K

    2003-01-01

    This paper presents a review of the organic solid-state polymer materials, which have become established as a new laser media. The photostability of these materials is discussed. Different types of solid-state lasers built around these materials are also reviewed.

  6. Study of the Optical and Physical Roles of a Dielectric Laser Dye Solvent Which Affects on the Dye Laser Operation

    Directory of Open Access Journals (Sweden)

    Riyad A.M. Ghazy

    2005-01-01

    Full Text Available It is well known that when the pump laser beam incidence on the laser dye liquid it will be absorbed. This absorption tends to heat the laser active medium, which is the laser dye solution. In view of this the correlated property of that active medium well change tends to shift the operated frequency and wavelength. Therefore, one of most interested dielectric, nonpolar, laser dye solvent was selected for this investigation, which is Benzene. A laser interferometer known as Mach Zhender Interferometer (MZI is constructed and used to measure the refractive index of the investigated solvent by counting the interfering fringes as a function of the angle of incidence of the incident laser beam. The temperature of that solvent is raised within the range 293-373 K by using a constructed heating system. The thermal behavior of the refractive index of Benzene is studied to estimate the thermo-optical coefficient of the refractive index, which is important to know the state convergence or divergence of the pump laser beam within the laser dye medium. Also, the dielectric constant of the dye solution is an important parameter for the laser operation. Therefore the dielectric constant and its thermal behavior of Benzene are calculated through the Maxwell’s relation to determine the thermal coefficient of the dielectric constant. The value of the number density which is equal the specific polarizability of the investigated solvent is estimated by using the obtained values of the refractive index and its variation with the temperature is studied too. Because the dependence of the mean polarizability of the dielectric constant through the Clausius-Mossotti relation the values of both mean polarizability and its thermal behavior are studied. In addition, since the molecular polarizability depends on the mean polarizability the value of it is determined. By using the values of mean polarizability the molecule radius is determined and using the Clausius

  7. Highly active ZnO rod-like nanomaterials: Synthesis, characterization and photocatalytic activity for dye removal

    Science.gov (United States)

    Hafez, Hoda S.

    2012-04-01

    Highly active ZnO rod-like nanostructures with pointed-shape ends have been synthesized via a simple hydrothermal method using acetic acid as an organic capping agent. The X-ray diffraction (XRD) pattern of the prepared sample reveals that the ZnO rod-like nanostructures are of pure hexagonal wurtzite structure. Morphology of the nanorods has been investigated by transmission electron microscope (TEM), which showed the formation of pointed nanorods of 30-50 nm in diameter and 400-650 nm in length. Optical properties have been investigated by UV-vis diffuse reflectance and photoluminescence spectroscopy. UV-vis absorption spectrum indicated that the ZnO nanorods have higher visible light harvesting as compared to the other morphologies in the literature. Intense room temperature green-red photoluminescence peaks at 486 nm and 564 nm has been observed for the prepared ZnO. This gives a good evidence of the presence of ionized oxygen vacancies which are favorable for photocatalytic reactions. The BET surface area and the average (BJH) adsorption pore size were 269.86 m2/g and 2.86 nm, respectively. The photocatalytic activity of the prepared sample was tested on the degradability of an industrial textile dye, Reactive Yellow 15 (Yellow GR), under sunlight irradiation. A 85.7% dye removal was achieved by applications of these rod-like nanostructures as a photocatalyst. The reusability of the synthesized ZnO nanomaterial has been investigated under the same experimental conditions for three time to evaluate the photoactivity of the photocatalyst.

  8. Photo-physical Characterisation of Novel Organic Dye-doped Solid-state Laser Materials

    Institute of Scientific and Technical Information of China (English)

    A.Penzkofer; A.Tyagi; T.Susdorf; D.del; Agua; O.García; R.Sastre; A.Costela; I.García-Moreno

    2007-01-01

    1 Results The development of tuneable solid-state organic dye lasers is a subject of considerable interest and research activity.Compared to conventional liquid dye lasers they have the advantage of being free of solvent handling,having small size,and being easy to operate.For high-performance solid-state dye lasers highly photo-stable dyes with low quantum yield of triplet formation and low triplet-triplet absorption cross-section in the lasing wavelength region are required.For solid state dye lasers ...

  9. High power CW diode-side-pumped Nd:YAG rod laser

    Institute of Scientific and Technical Information of China (English)

    Hailin Wang(王海林); Weiling Huang(黄维玲); Zhuoyou Zhou(周卓尤); Hongbing Cao(曹红兵)

    2003-01-01

    We report on the characterization of a diode-side-pumped Nd:YAG rod laser operating at high CW output power. A four-fold pump configuration is designed and the pump light is directly coupled into the Nd:YAG rod without the help of any cylindrical lenses. The distribution of pump light in the Nd:YAG rod has been calculated by using ray tracing program. The thermal lens effect of the Nd:YAG rod has been experimentally measured. A maximum output power of 800 W at 1064 nm in multimode operation is obtained for a pump power of 2400 W with 33% optical-optical efficiency. At the same time, the maximum beam parameter product of 25 mm.mrad is achieved.

  10. Temporal dynamics of high repetition rate pulsed single longitudinal mode dye laser

    Indian Academy of Sciences (India)

    G Sridhar; V S Rawar; S Singh; L M Gantayet

    2013-08-01

    Theoretical and experimental studies of temporal dynamics of grazing incidence grating (GIG) cavity, single-mode dye laser pumped by high repetition rate copper vapour laser (CVL) are presented. Spectral chirp of the dye laser as they evolve in the cavity due to transient phase dynamics of the amplifier gain medium is studied. Effect of grating efficiency, focal spot size, pump power and other cavity parameters on the temporal behaviour of narrow band dye laser such as build-up time, pulse shape and pulse width is studied using the four level dye laser rate equation and photon evolution equation. These results are compared with experimental observations of GIG single-mode dye laser cavity. The effect of pulse stretching of CVL pump pulse on the temporal dynamics of the dye laser is studied.

  11. High-definition color image in dye thermal transfer printing by laser heating

    Science.gov (United States)

    Kitamura, Takashi

    1999-12-01

    In laser thermal transfer printing using dye sublimation type medium, a high definition and continuous tone image can be obtained easily because the laser beam is focused to small spot and heat energy can be controlled by the pulse width modulation of laser light. The donor ink sheet is composed of the laser absorbing layer and sublimation dye layer. The tone reproduction was depend on the mixture ratio of dye to binder and thickness of ink layer. The four color ink sheets such as cyan, magenta, yellow and black were prepared for color printing image which have a high resolution and good continuous tone reproduction using sublimation dye transfer printing by laser heating.

  12. Spectral selectivity in optical fiber capillary dye lasers.

    Science.gov (United States)

    Mobini, Esmaeil; Abaie, Behnam; Peysokhan, Mostafa; Mafi, Arash

    2017-05-01

    We explore the spectral properties of a capillary dye laser in the highly multimode regime. Our experiments indicate that the spectral behavior of the laser does not conform to a simple Fabry-Perot (FP) analysis; rather, it is strongly dictated by a Vernier resonant mechanism involving multiple modes, which propagate with different group velocities. The laser operates over a very broad spectral range and the Vernier effect gives rise to a free spectral range, which is orders of magnitude larger than that expected from a simple FP mechanism. The theoretical calculations presented confirm the experimental results. Propagating modes of the capillary fiber are calculated using the finite-element method and it is shown that the optical path lengths resulting from simultaneous beatings of these modes are in close agreement with the optical path lengths directly extracted from the Fourier transform of the experimentally measured laser emission spectra.

  13. Decoloration of Azo Dye Sunset Yellow by a Coaxial Insulated-Rod-to-Cylinder Underwater Streamer Discharge System

    Institute of Scientific and Technical Information of China (English)

    温小琼; 王明; 丁振峰; 刘贵师

    2012-01-01

    A coaxial insulated-rod-to-cylinder underwater streamer discharge system capable of injecting plasma into a large volume of water was developed and employed to decolorize azo dye sunset yellow. The rod type anode was covered by an insulator tube with a wall thickness of 0.4 mm. A series of slits with a width of 20 μm to 80 μm and a length of about 4 mm were cut onto the wall of the insulator tube. Depending on the solution conductivity, a cylindrical discharge region with a length of 60 mm and a wall thickness of 5 mm to 11 mm forms in the reactor. The influence of the solution conductivity, pH and pulse frequency on the decoloration of sunset yellow was investigated. The results show that the solution conductivity has little effect, while the solution pH and the pulse frequency have significant influence on the decoloration rate of sunset yellow. The decoloration rate of sunset yellow is increased with the increase in pulse frequency. A lower pH in solution promotes the decoloration of sunset yellow while a higher pH inhibits it.

  14. A simple fabrication for sulfur doped graphitic carbon nitride porous rods with excellent photocatalytic activity degrading RhB dye

    Science.gov (United States)

    Fan, Qianjing; Liu, Jianjun; Yu, Yingchun; Zuo, Shengli; Li, Baoshan

    2017-01-01

    Constructing special nanostructures with large surface areas and tuning the band gap by element doping are efficient strategies to enhance the photocatalytic activity of semiconductor materials. Here we combined both strategies in one material to form sulfur-doped graphitic carbon nitride porous rods (S-pg-C3N4) in one pot by simply pyrolysis of the melamine-trithiocyanuric acid complex with different temperatures. The samples were characterized by XRD, FT-IR, and elemental analysis; nitrogen adsorption isotherms, SEM and TEM images; and UV-vis DRS and photoluminescence spectra. Characterizations showed that S-pg-C3N4 possessed porous rod structure with a larger surface area (20-52 m2/g) than that of bulk g-C3N4, and the surface area of the S-pg-C3N4 samples increased with the increase of heating temperature. Meanwhile, the trace sulfur remained in the framework of g-C3N4 formed sulfur doped g-C3N4, and the visible light absorption edge of the S-pg-C3N4 was extended, corresponding to a narrowed band gap. As a result, the S-pg-C3N4 samples exhibited an enhanced physical adsorption and photocatalytic activity in the degradation of Rhodamine B dye under visible light.

  15. Photophysical and laser characteristics of pyrromethene 567 dye: Experimental and theoretical studies

    Indian Academy of Sciences (India)

    K K Jagtap; D K Maity; A K Ray; K Dasgupta; S K Ghosh

    2010-11-01

    Narrow-band laser performance of alcohol solutions of pyrromethene 567 (PM567) and rhodamine 6G (RH6G) dye was investigated using a home-made GIG- configured dye laser, excited by the second-harmonic radiation (at 532 nm) of a pulsed Nd:YAG laser. Higher laser efficiency was observed with PM567 dye (∼ 23% peak) in comparison to the commonly used RH6G dye (16.5%), in spite of much lower fluorescence quantum efficiency of the PM567 (0.83) vis-à-vis RH6G (0.98) dye solutions in ethanol. First principle-based electronic structure calculations were performed on PM567 dye in the ground (0) and excited states (1) using density functional theory to elucidate the structure and photophysical properties of the dye.

  16. Spectroscopy and laser performance of new BF{sub 2} complex dyes in solution

    Energy Technology Data Exchange (ETDEWEB)

    Allik, T.H. [Science Applications International Corp., McLean, VA (United States); Hermes, R.E. [Agilase Inc., White Rock, NM (United States); Sathyamoorthi, G.; Boyer, J.H. [Univ. of New Orleans, LA (United States). Dept. of Chemistry

    1994-12-31

    Four new BF{sub 2}-complex laser dyes have been synthesized and spectroscopic and laser studies have been performed. The 8-cyano-pyrromethene-BF{sub 2} complexes showed the best performance with red emission and slope efficiencies as high as 48% when pumped with a frequency doubled ND:YAG laser. Additionally, three previously known pyrromethene-BF{sub 2} complex dyes obtained from a commercial source were tested. These dyes showed a relative efficiency of greater than 80%, with one (PM-580) displaying a slope efficiency of 89%. This efficiency is the highest reported for any dye laser.

  17. Measurement of the figure of merit of indigenously developed Nd-doped phosphate laser glass rods for use in high power lasers

    Indian Academy of Sciences (India)

    A P Kulkarni; S Jain; M P Kamath; A S Joshi; P A Naik; P D Gupta; K Annapurna; A K Mandal; B Karmakar; R Sen

    2014-01-01

    High energy, high power (HEHP) Nd:glass laser systems are used for inertial confinement fusion and equation of state (EOS) studies of materials at high temperature and pressure. A program has been undertaken for the indigenous development of Nd-doped phosphate laser glass rods and discs for HEHP lasers. In this paper, we report the characterization of the Nd-doped phosphate laser glass rods produced under this program and compare the indigenously developed laser glass to LHG-8 laser glass of M/s Hoya, Japan. We experimentally measured the values of the stimulated emission cross-section () and coefficient of intensity-dependent refractive index (2) and hence the figure of merit = /2 of the indigenous phosphate laser glass rods. This value of figure of merit is found comparable to the reported value of identically doped Nd:glass rods.

  18. Measurement of flow fluctuations in single longitudinal mode pulsed dye laser

    Indian Academy of Sciences (India)

    V S Rawat; N Kawade; G Sridhar; Sunita Singh; L M Gantayet

    2014-02-01

    A simple technique had been demonstrated for measuring flow-induced fluctuations in the single longitudinal mode (SLM) pulsed dye laser. Two prominent frequency components of 10.74 Hz and 48.83 Hz were present in the output of the Nd:YAG-pumped SLM dye laser. The flow-induced frequency component of 48.83 Hz was present due to the revolution per minute of the motor attached to the magnetically coupled gear pump. The time average bandwidth of 180 MHz has been obtained for this SLM dye laser. The effect of pump pulse energy on the bandwidth of the SLM dye laser was studied. The bandwidth of the SLM dye laser was increased to 285 MHz from 180 MHz, when the pump pulse energy was increased to 0.75 mJ from 0.15 mJ for a constant dye flow velocity of 0.5 m/s.

  19. Laser transformation hardening on rod-shaped carbon steel byGaussian beam

    Institute of Scientific and Technical Information of China (English)

    Jong-Do KIM; Myeong-Hoon LEE; Su-Jin LEE; Woon-Ju KANG

    2009-01-01

    Laser transformation hardening(LTH) is one of the laser surface modification processes. The surface hardening of rod-shaped carbon steel (SM45C) was performed by lathe-based laser composite processor with Gaussian-beam optical head. The LTH characteristics by dominant processes, longitudinal and depth directional hardness distributions and behaviors of phase transformation in hardened zones were examined. Especially, two concepts of circumferential speed and theoretical overlap rate were applied. When laser power increased or circumferential speed decreased, the surface hardening depth gradually increases due to the increased heat input. Moreover, the longitudinal hardness distribution particularly shows periodicity of repetitive increase and decrease, which results from tempering effect by overlap. Finally, the feasibility of laser transformation hardening is verified by using the beam with Gaussian intensity distribution.

  20. A Moiré Cavity Plasmonic Dye Laser

    Science.gov (United States)

    Karademir, Ertugrul; Balci, Sinan; Kocabas, Coskun; Aydinli, Atilla

    2015-03-01

    From its first conception to its first demonstration, plasmonic lasers have been an intriguing topic of research. In this work, Moiré gratings which manifest a cavity state in the SPP dispersion curve. We used a reverse Kretschmann setup to decouple the amplified light component of SPPs. We employed a Moiré cavity with 250 +256 nm periodicity together with a Styryl 7 laser dye dissolved in ethylene glycol in 5 mM concentration and obtained a lasing at 718 nm. Pumping threshold was 1.5 mJ/cm2 with FWHM of 2.8 nm. Furthermore, periodicities of 242 +248 nm and 260 +266 nm resulted in proportional shift of the lasing peak. We did not observe any lasing action on samples with Au and Ti coatings, although solely Au coated samples showed plasmonic modes in the spectrum. Resulting lasing peak is highly TM polarized. Reflection map measurements confirm that lasing mode is supported with the cavity state of the metallic Moiré cavity and simulations support reflection map measurements. Thus, we demonstrated, to our knowledge, the first plasmonic dye laser on a Moiré cavity. TUBITAK 110T790, 110T589, 112T091.

  1. Temporal output profile of gain-coupled distributed feedback dye laser

    Science.gov (United States)

    Pasandideh, K.; Souri, S.; Gohari Kamel, N.; Sadighi-Bonabi, R.

    2017-08-01

    The lasing mechanism and temporal output profile of distributed feedback dye lasers is investigated, using a model based on induced polarization in the dye solution, where a more accurate behavior of the laser output is predicted. It is found that the temporal output profile of the laser is mostly determined by the concentration of dye solution and the lifetime of the upper laser level of dye molecules. To a large extent, the results of this work agree with experimental studies, even at high-level pump intensities where the self Q-switched model fails to be applied. Especially, the experimentally observed irregular intensity profile of laser output is explained. It is also shown that, when pumping dye solution by narrower pulses, the single-pulse output mode can be realized in the wider range of pump intensities and the pulsewidth stability of laser can be improved.

  2. Dual-rod Yb: YAG laser for high-power and high-brightness applications

    Energy Technology Data Exchange (ETDEWEB)

    Honea, E C; Beach, R; Mitchell, S C; Skidmore, J A; Emanuel, M A; Sutton, S B; Payne, S A; Avizonis, P V; Monroe, R S; Harris, D G

    2000-03-13

    The authors describe a diode-pumped Yb:YAG laser producing 1,080 W cw with 27.5% optical-optical efficiency and 532 W Q-switched with M{sup 2} = 2.2 and 17% optical-optical efficiency. The laser uses two composite Yb:YAG rods separated by a 90 degree quartz rotator for bifocusing compensation. A microlensed diode array end-pumps each rod using a hollow lens duct for pump delivery. By changing resonator parameters, they can adjust the fundamental mode size and the output beam quality. Using a flattened gaussian intensity profile to calculate the mode fill efficiency and clipping losses, the authors compare experimental data to modeled output power vs beam quality.

  3. Kiton red S dye: Photophysical, photostability, photothermal and narrow-band laser performances using different solvents

    Indian Academy of Sciences (India)

    Krishna K Jagtap; Alok K Ray; S K Pardeshi; K Dasgupta

    2010-11-01

    Many aspects of photophysical, photostability and laser properties of kiton red S dye remain unresolved, particularly for pumping with 578 nm radiation of CVL and 532 nm output of Nd:YAG lasers, and these are studied using different alcohol- and water-based binary solvents. Our results show that methanol is better suited for low and high-repetition-rate KRS dye lasers because of its superior laser efficiency, photostability as well as photothermal properties.

  4. Development of Mechanical Sealing and Laser Welding Technology to Instrument Thermocouple for Nuclear Fuel Test Rod

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Chang-Young; Ahn, Sung-Ho; Hong, Jin-Tae; Kim, Ka-Hye; Huh, Sung-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Zircaloy-4 of the nuclear fuel test rod, AISI 316L of the mechanical sealing parts, and the MI (mineral insulated) cable at a thermocouple instrumentation are hetero-metals, and are difficult to weld to dissimilar materials. Therefore, a mechanical sealing method to instrument the thermocouple should be conducted using two kinds of sealing process as follows: One is a mechanical sealing process using Swagelok, which is composed of sealing components that consists of an end-cap, a seal tube, a compression ring and a Swagelok nut. The other is a laser welding process used to join a seal tube, and an MI cable, which are made of the same material. The mechanical sealing process should be sealed up with the mechanical contact compressed by the strength forced between a seal tube and an end-cap, and the laser welding process should be conducted to have no defects on the sealing area between a seal tube and an MI cable. Therefore, the mechanical sealing and laser welding techniques need to be developed to accurately measure the centerline temperature of the nuclear fuel test rod in an experimental reactor. The mechanical sealing and laser welding tests were conducted to develop the thermocouple instrumentation techniques for the nuclear fuel test rod. The optimum torque value of a Swagelok nut to seal the mechanical sealing part between the end-cap and seal tube was established through various torque tests using a torque wrench. The optimum laser welding conditions to seal the welding part between a seal tube and an MI cable were obtained through various welding tests using a laser welding system.

  5. Analytical model of transient thermal effect on convectional cooled end-pumped laser rod

    Indian Academy of Sciences (India)

    Khalid S Shibib; Mohammad A Munshid; Kadim A Hubiter

    2013-10-01

    The transient analytical solutions of temperature distribution, stress, strain and optical path difference in convectional cooled end-pumped laser rod are derived. The results are compared with other works and good agreements are found. The effects of increasing the edge cooling and face cooling are studied. It is found that an increase in the edge cooling has significant effect on reducing the maximum temperature that can be reached in the laser rod but it has no effect on the value of optical path difference. It is also found that increasing this type of cooling significantly reduces the time required to reach the thermal equilibrium with a slight increase in the max. tensile hoop stress that can be reached as the cooling increases. On the other hand, increase in face cooling reduces the response time, optical path difference and the maximum temperature that can be reached in the laser rod but a significant increase in the max. tensile hoop stress is observed. A matching between the advantages of these two type of cooling may be useful for a designer.

  6. Measurement and compensation of frequency chirping in pulsed dye laser amplifiers

    NARCIS (Netherlands)

    Reinhard, I.; Gabrysch, M.; Von Weikersthal, B. Fischer; Jungmann, K.; Zu Putlitz, G.

    1996-01-01

    Rapid changes of the refractive index in the active medium of a pulsed, excimer laser pumped dye laser amplifier were investigated with an optical heterodyne technique. Time-dependent shifts in the phase of optical light waves could be observed which for Coumarin 102, 153 and 307 dyes at wavelengths

  7. Development of the plastic solid-dye cell for tunable solid-state dye lasers and study on its optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Do Kyeong; Lee, Jong Min; Cha, Byung Heon; Jung, E. C.; Kim, Hyun Su; Lim, Gwon

    2001-01-01

    we have fabricated solid-state dyes with PMMA and sol-gel materials. We developed single longitudianl mode solid-state dye laser with the linewidth of less than 500MHz. We have constructed a self-seeded laser and observed the increase of the output power because of self-seeding effect. We investigated the operating characteristics of the dualwave laser oscillator and DFDL with solid-state dyes. And we have constructed the 3-color solid-state dye laser oscillator and amplifier system and observed 3-color operation. We also improved the laser oscliiator with disk-type solid-state dye cell which can be translated and rotated with the help of the two stepping motors. With the help of computer control, we could constantly changed the illuminated area of the dye cell and, therefore, were able to achieve long time operation and to use almost the entire region of the solid-state dye cell.

  8. Circularly polarized laser emission induced in isotropic and achiral dye systems

    Science.gov (United States)

    Cerdán, Luis; García-Moreno, Sara; Costela, Angel; García-Moreno, Inmaculada; de La Moya, Santiago

    2016-06-01

    The production of efficient, tunable, and switchable circularly polarized laser emission would have far reaching implications in optical communications or biophotonics. In this work, it is demonstrated the direct generation of circularly polarized (CP) laser emission in achiral and isotropic dye laser systems without the use of extracavity polarizing elements, and without resorting to chiral dyes, chiral liquid crystal matrices, or interferometric methods. The origin of this ellipticity arises from the dynamic birefringence induced by the strong and polarized laser pumping and the subsequent orientation anisotropy of the excited molecular dipoles. A complete polarimetric characterization of the polarization state of conventional dye laser oscillators as a function of different experimental parameters is performed and it is shown that the generated light always possesses a certain level of circularity that changes in a distinctive way with pump energy and polarization. These results demonstrate that it is possible to generate and modulate CP laser light from efficient and photostable conventional laser dyes.

  9. Polymer photonic crystal dye lasers as label free evanescent cell sensors

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Lopacinska, Joanna M.; Jakobsen, Mogens Havsteen

    2009-01-01

    . The lasers are fabricated by combined nanoimprint and photolithography (CNP) in Ormocore hybrid polymer doped with the laser dye Pyrromethene 597. The lasers emit in the chip plane at a wavelength around 595 nm when pumped with 5 ns pulses from a compact frequency doubled Nd:YAG laser. We investigate...

  10. High-repetition-rate femtosecond dye amplifier using a laser-diode-pumped neodymium:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Zysset, B.; LaGasse, M.J.; Fujimoto, J.G.; Kafka, J.D.

    1989-02-06

    A high-repetition-rate femotosecond dye amplifier is demonstrated using a laser-diode-pumped Q-switched Nd:YAG laser. Amplification of wavelength-tunable 300-fs pulses from a synchronously mode-locked rhodamine dye laser is achieved with a saturated gain of 70 and a small gain of 200 at a repetition rate of 800 Hz. Maximum pulse energies of 40 nJ are obtained, and pulse compression to as short as 30 fs is demonstrated.

  11. Taming fluorescence yield of dye insensitive to temperature by non-covalent complex with the host CB[7] for aqueous dye lasers

    Indian Academy of Sciences (India)

    Monika Gupta; Krishna K Jagtap; V Sudarsan; Alok K Ray

    2014-02-01

    Quantum yield of fluorescence (QYF) of widely used Rhodamine (RhB) dye in ethanol and water was observed to decrease rapidly with increase in temperature of the dye solutions, which was correlated to enhanced torsional motion of its flexible diethylamino groups. This is harmful for its use in high-average power dye lasers, pumped by copper vapour laser (CVL) or diodepumped solid-state green laser (DPSSGL), in which bulk temperature of the dye solution was found to increase due to the heat generated by circulation pumps and non-radiative decay processes of excited dye molecules. The QYF of RhB dye in water was found to be not sensitive to temperature in the practical operating region 16–25°C of dye laser by adopting supramolecular route to form an inclusion complex of RhB with the container molecule cucurbit[7]uril (CB[7]).

  12. A linewidth-narrowed and frequency-stabilized dye laser for application in laser cooling of molecules.

    Science.gov (United States)

    Dai, D P; Xia, Y; Yin, Y N; Yang, X X; Fang, Y F; Li, X J; Yin, J P

    2014-11-17

    We demonstrate a robust and versatile solution for locking the continuous-wave dye laser for applications in laser cooling of molecules which need linewidth-narrowed and frequency-stabilized lasers. The dye laser is first stabilized with respect to a reference cavity by Pound-Drever-Hall (PDH) technique which results in a single frequency with the linewidth 200 kHz and short-term stabilization, by stabilizing the length of the reference cavity to a stabilized helium-neon laser we simultaneously transfer the ± 2 MHz absolute frequency stability of the helium-neon laser to the dye laser with long-term stabilization. This allows the dye laser to be frequency chirped with the maximum 60 GHz scan range while its frequency remains locked. It also offers the advantages of locking at arbitrary dye laser frequencies, having a larger locking capture range and frequency scanning range to be implemented via software. This laser has been developed for the purpose of laser cooling a molecular magnesium fluoride beam.

  13. High frame rate multi-resonance imaging refractometry with distributed feedback dye laser sensor

    OpenAIRE

    2015-01-01

    High frame rate and highly sensitive imaging of refractive index changes on a surface is very promising for studying the dynamics of dissolution, mixing and biological processes without the need for labeling. Here, a highly sensitive distributed feedback (DFB) dye laser sensor for high frame rate imaging refractometry without moving parts is presented. DFB dye lasers are low-cost and highly sensitive refractive index sensors. The unique multi-wavelength DFB laser structure presented here comp...

  14. Assembly of Acircular SnO2 Rod Using Optical Tweezers and Laser Curing of Metal Nanoparticles

    Science.gov (United States)

    Nam, Chanhyuk; Hong, Daehie; Chung, Jaeik; Chung, Jaewon; Hwang, Insung; Lee, Jongheun; Ko, Seunghwan; Grigoropoulos, Costas P.

    2010-05-01

    Acicular tin dioxide (SnO2) rods (1-2 µm in diameter, 5-20 µm long) were assembled and fused on the patterned gold electrode by an optical tweezer. In addition, the electrical contact between the assembled SnO2 rod and the gold electrode was improved by laser curing of gold nanoparticles and the subsequent sintering in the oven. Here, the nanoparticles covered the entire area of the assembled SnO2 rod by evaporating a droplet of nanoparticle solution dripped on the assembled SnO2 rod. Subsequently, nanoparticles near the contact area between the rod and electrode were locally cured by direct heating with a focused infrared laser beam, which induced desorption of the surface monolayer. Therefore, the cured gold nanoparticles could be sintered after the non-laser irradiated nanoparticles were cleaned by the initial solvent application. Without sintering of the nanoparticles, the resistance of the assembled SnO2 rod was measured over several MΩ. After the nanoparticle sintering it could be reduced to a few hundred kΩ, which was in agreement with the resistance of the assembled SnO2 rod.

  15. Technology and engineering aspects of high power pulsed single longitudinal mode dye lasers

    Science.gov (United States)

    Rawat, V. S.; Mukherjee, Jaya; Gantayet, L. M.

    2015-09-01

    Tunable single mode pulsed dye lasers are capable of generating optical radiations in the visible range having very small bandwidths (transform limited), high average power (a few kW) at a high pulse repetition rate (a few tens of kHz), small beam divergence and relatively higher efficiencies. These dye lasers are generally utilized laser dyes dissolved in solvents such as water, heavy water, ethanol, methanol, etc. to provide a rapidly flowing gain medium. The dye laser is a versatile tool, which can lase either in the continuous wave (CW) or in the pulsed mode with pulse duration as small as a few tens of femtoseconds. In this review, we have examined the several cavity designs, various types of gain mediums and numerous types of dye cell geometries for obtaining the single longitudinal mode pulsed dye laser. Different types of cavity configuration, such as very short cavity, short cavity with frequency selective element and relatively longer cavity with multiple frequency selective elements were reviewed. These single mode lasers have been pumped by all kinds of pumping sources such as flash lamps, Excimer, Nitrogen, Ruby, Nd:YAG, Copper Bromide and Copper Vapor Lasers. The single mode dye lasers are either pumped transversely or longitudinally to the resonator axis. The pulse repletion rate of these pump lasers were ranging from a few Hz to a few tens of kHz. Physics technology and engineering aspects of tuning mechanism, mode hop free scanning and dye cell designs are also presented in this review. Tuning of a single mode dye laser with a resolution of a few MHz per step is a technologically challenging task, which is discussed here.

  16. Rate equation simulation of temporal characteristics of a pulsed dye laser oscillator

    Indian Academy of Sciences (India)

    S Kundu; K Dasgupta; S Sasikumar; J Singh; A K Ray; S Sinha

    2010-11-01

    A time-dependent, two-dimensional (in space) rate equation model of a transversely-pumped pulsed dye laser oscillator, which incorporates transverse pump intensity variation in the presence of intracavity dye laser radiation, is proposed to under-stand and predict its temporal behaviour. The model yields output pulses which agree well with experimental results using rhodamine 6G and kiton red dyes. The shape, amplitude and temporal position of the simulated pulse within the pump pulse vary dramatically across the tuning range of each dye depending on the relative gain and loss values.

  17. Spectroscopic properties and amplified spontaneous emission of fluorescein laser dye in ionic liquids as green media

    Science.gov (United States)

    AL-Aqmar, Dalal M.; Abdelkader, H. I.; Abou Kana, Maram T. H.

    2015-09-01

    The use of ionic liquids (ILs) as milieu materials for laser dyes is a promising field and quite competitive with volatile organic solvents and solid state-dye laser systems. This paper investigates some photo-physical parameters of fluorescein dye incorporated into ionic liquids; 1-Butyl-3-methylimidazolium chloride (BMIM Cl), 1-Butyl-3-methylimidazolium tetrachloroaluminate (BMIM AlCl4) and 1-Butyl-3-methylimidazolium tetrafluoroborate (BMIM BF4) as promising host matrix in addition to ethanol as reference. These parameters are: absorption and emission cross-sections, fluorescence lifetime and quantum yield, in addition to the transition dipole moment, the attenuation length and oscillator strength were also investigated. Lasing characteristics such as amplified spontaneous emission (ASE), the gain, and the photostability of fluorescein laser dye dissolved in different host materials were assessed. The composition and properties of the matrix of ILs were found that it has great interest in optimizing the laser performance and photostability of the investigated laser dye. Under transverse pumping of fluorescein dye by blue laser diode (450 nm) of (400 mW), the initial ASE for dye dissolved in BMIM AlCl4 and ethanol were decreased to 39% and 36% respectively as time progressed 132 min. Relatively high efficiency and high fluorescence quantum yield (11.8% and 0.82% respectively) were obtained with good photostability in case of fluorescein in BMIM BF4 that was decreased to ∼56% of the initial ASE after continuously pumping with 400 mW for 132 min.

  18. Superradiant dye solution laser with two-photon picosecond optical pumping

    Energy Technology Data Exchange (ETDEWEB)

    Prokhorenko, V.I.; Tikhonov, E.A.; Shpak, M.T.

    1981-01-01

    A superradiant (superfluorescent) dye solution laser with two-photon picosecond pumping was constructed for the first time. A preliminary study was made of the principal characteristics of the output radiation of this laser which performed up-conversion of the frequency of the pump radiation. The physical mechanisms governing the operation of lasers of this type were analyzed.

  19. Pulsed dye laser treatment for facial flat warts.

    Science.gov (United States)

    Grillo, E; Boixeda, P; Ballester, A; Miguel-Morrondo, A; Truchuelo, T; Jaén, P

    2014-01-01

    The facial flat wart is not only a contagious viral disease, but also a cause of a distressing cosmetic problem. Although there are many therapeutic options, including salicylic acid, imiquimod, cryotherapy, retinoids, intralesional immunotherapy, and topical 5-aminolevulinic acid photodynamic therapy among others, no monotherapy has been proved to achieve complete remission in every case. Treatment with pulsed dye laser (PDL) seems to be a promising therapeutic option. To assess the efficacy and safety of PDL in a series of patients with viral flat warts on the face, in this prospective study, 32 patients were treated with PDL at 595-nm wavelength, a laser energy density of 9 or 14 J/cm(2) with a spot size of 7 or 5 mm, respectively, with air cooling and a pulse duration of 0.5 millisecond. A complete response was noted in 14 patients (44%), and an excellent response was observed in 18 patients (56%) with 1-year follow-up, with only four recurrences. No significant side effects were reported except intense transitory purpuric response. We consider that PDL is a good option of treatment for flat warts on the face due to its good clinical results, fast response, and low incidence of side effects. © 2013 Wiley Periodicals, Inc.

  20. Infantile hemangioma: pulsed dye laser versus surgical therapy

    Science.gov (United States)

    Remlova, E.; Dostalova, T.; Michalusova, I.; Vranova, J.; Jelinkova, H.; Hubacek, M.

    2014-05-01

    Hemangioma is a mesenchymal benign tumor formed by blood vessels. Anomalies affect up to 10% of children and they are more common in females than in males. The aim of our study was to compare the treatment efficacy, namely the curative effect and adverse events, such as loss of pigment and appearance of scarring, between classical surgery techniques and laser techniques. For that reason a group of 223 patients with hemangioma was retrospectively reviewed. For treatment, a pulsed dye laser (PDL) (Rhodamine G, wavelength 595 nm, pulsewidth between 0.45 and 40 ms, spot diameter 7 mm, energy density 9-11 J cm-2) was used and the results were compared with a control group treated with classical surgical therapy under general anesthesia. The curative effects, mainly number of sessions, appearance of scars, loss of pigment, and relapses were evaluated as a marker of successful treatment. From the results it was evident that the therapeutic effects of both systems are similar. The PDL was successful in all cases. The surgery patients had four relapses. Classical surgery is directly connected with the presence of scars, but the system is safe for larger hemangiomas. It was confirmed that the PDL had the optimal curative effect without scars for small lesions (approximately 10 mm). Surgical treatment under general anesthesia is better for large hemangiomas; the disadvantage is the presence of scars.

  1. Developing a narrow-line laser spectrometer based on a tunable continuous-wave dye laser

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chun; Lv, Shasha; Bi, Jin [Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Liu, Fang [College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093 (China); Li, Liufeng; Chen, Lisheng [Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan 430071, China and Laboratory of Atomic Frequency Standards, Chinese Academy of Sciences, Wuhan 430071 (China)

    2014-08-15

    We present the development of a dye-laser-based spectrometer operating at 550–600 nm. The spectrometer will be used to detect an ultra-narrow clock transition ({sup 1}S{sub 0}-{sup 3}P{sub 0}) in an Ytterbium optical lattice clock and perform high-resolution spectroscopy of iodine molecules trapped in the sub-nanometer channels of zeolite crystal (AlPO{sub 4}-11). Two-stage Pound-Drever-Hall frequency stabilization is implemented on the tunable continuous-wave dye laser to obtain a reliable operation and provide stable laser radiations with two different spectral linewidths. In the first-stage frequency locking, a compact home-built intracavity electro-optic modulator is adopted for suppressing fast frequency noise. With an acquisition time of 0.1 s the 670-kHz linewidth of the free-running dye laser is reduced to 2 kHz when locked to a pre-stabilization optical cavity with a finesse of 1170. When the pre-stabilized laser is locked to a high-finesse optical cavity, a linewidth of 1.4 Hz (2 s) is observed and the frequency stability is 3.7 × 10{sup −15} (3 s). We also measure and analyze the individual noise contributions such as those from residual amplitude modulation and electronic noise. The ongoing upgrades include improving long-term frequency stability at time scales from 10 to 100 s and implementing continuous frequency scan across 10 GHz with radio-frequency precision.

  2. Measuring the Dispersion Curve of a PMMA-Fibre Optic Cable Using a Dye Laser

    Science.gov (United States)

    Zorba, Serkan; Farah, Constantine; Pant, Ravi

    2010-01-01

    An advanced undergraduate laboratory experiment is outlined which uses a dye laser to map out the chromatic dispersion curve of a polymethyl methacrylate (PMMA) optical fibre. Seven different wavelengths across the visible spectrum are employed using five different dyes. The light pulse is split into two pulses, one to a nearby photodetector and…

  3. Measuring the Dispersion Curve of a PMMA-Fibre Optic Cable Using a Dye Laser

    Science.gov (United States)

    Zorba, Serkan; Farah, Constantine; Pant, Ravi

    2010-01-01

    An advanced undergraduate laboratory experiment is outlined which uses a dye laser to map out the chromatic dispersion curve of a polymethyl methacrylate (PMMA) optical fibre. Seven different wavelengths across the visible spectrum are employed using five different dyes. The light pulse is split into two pulses, one to a nearby photodetector and…

  4. Micrometric rods grown by nanosecond pulsed laser deposition of boron carbide

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Quintas, Ignacio; Oujja, Mohamed; Sanz, Mikel; Benitez-Cañete, Antonio [Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Chater, Richard J. [Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Cañamares, Maria Vega [Instituto de Estructura de la Materia, CSIC, Serrano 119, 28006 Madrid (Spain); Marco, José F. [Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Castillejo, Marta, E-mail: marta.castllejo@iqfr.csic.es [Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain)

    2015-02-15

    Highlights: • Micrometric rods obtained by ns pulsed laser deposition of boron carbide at 1064 and 266 nm. • At 1064 nm microrods display crystalline polyhedral shape with sharp edges and flat sides. • Microrods consist of a mixture of boron, boron oxide, boron carbide and aliphatic hydrocarbons. - Abstract: Micrometric size rods have been fabricated via pulsed laser deposition in vacuum from boron carbide targets using nanosecond pulses of 1064 and 266 nm and room temperature Si (1 0 0) substrates. Morphological, structural and chemical characterization of the microrods was made by applying scanning electron microscopy, focussed ion beam microscopy coupled to secondary ion mass spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy and micro-Raman spectroscopy. Ablation at 1064 nm favours the formation of microrods with high aspect ratio, sharp edges and pyramidal tips, typically 10 μm long with a cross section of around 2 μm × 2 μm. Differently, at 266 nm the microrods are of smaller size and present a more globular aspect. The analyses of the microrods provide information about their crystalline nature and composition, based on a mixture which includes boron, boron oxide and boron carbide, and allows discussion of the wavelength dependent growth mechanisms involved.

  5. Comparison of the treatment of vascular lesions with the copper-vapor laser and flashlamp-pumped dye laser

    Science.gov (United States)

    Flock, Stephen T.; Waner, Milton; McGrew, Ben; Colvin, G. B.; Montague, Donna

    1992-08-01

    Vascular lesions such as port-wine stains and telangiectases are sometimes treated with carbon-dioxide lasers, argon lasers or argon-pumped dye lasers; however these lasers are non- specific in their thermal effect on tissues and as a result often cause significant scarring. Recently, evidence has accumulated that the flashlamp-pumped dye (585 nm) and copper- vapor (578 nm) lasers, which produce pulsed light that is efficiently absorbed by hemoglobin, are more selective in coagulating abnormal vascular tissue and as a result give a superior clinical result. It is not yet clear what the most important physical and biological mechanisms are during the light-tissue interaction mediated by these two lasers. The post-treatment sequence of events is different for tissue irradiated by each laser; most significantly, the flashlamp-pumped dye laser causes significant transient purpura, whereas the copper vapor laser causes blanching and eschar formation. The clinical outcome, that is regression of the lesion, is equally successful with either laser although some evidence has accumulated showing that the flashlamp-pumped dye laser is best suited to the treatment of small vessel disease while the copper-vapor laser is better for the treatment of large vessel disease. In this paper, we will discuss our observations of the treatment of vascular lesions on humans with the copper-vapor and flashlamp-pumped dye lasers using empirically derived efficacious treatment parameters. Mathematical models of light and heat propagation and in vivo experiments involving mice ears and rat skin flaps will be used to elucidate what we feel are the important underlying mechanisms of this vascular lesion laser therapy.

  6. Performance study of highly efficient 520 W average power long pulse ceramic Nd:YAG rod laser

    Science.gov (United States)

    Choubey, Ambar; Vishwakarma, S. C.; Ali, Sabir; Jain, R. K.; Upadhyaya, B. N.; Oak, S. M.

    2013-10-01

    We report the performance study of a 2% atomic doped ceramic Nd:YAG rod for long pulse laser operation in the millisecond regime with pulse duration in the range of 0.5-20 ms. A maximum average output power of 520 W with 180 J maximum pulse energy has been achieved with a slope efficiency of 5.4% using a dual rod configuration, which is the highest for typical lamp pumped ceramic Nd:YAG lasers. The laser output characteristics of the ceramic Nd:YAG rod were revealed to be nearly equivalent or superior to those of high-quality single crystal Nd:YAG rod. The laser pump chamber and resonator were designed and optimized to achieve a high efficiency and good beam quality with a beam parameter product of 16 mm mrad (M2˜47). The laser output beam was efficiently coupled through a 400 μm core diameter optical fiber with 90% overall transmission efficiency. This ceramic Nd:YAG laser will be useful for various material processing applications in industry.

  7. Multimode laser emission from dye-doped hollow polymer optical fibre

    Indian Academy of Sciences (India)

    C L Linslal; Jaison Peter; S Mathew; M Kailasnath

    2014-02-01

    Well-resolved multimode laser emission was observed for the first time from a freestanding microring cavity based on Rhodamine B dye-doped hollow polymer optical fibre by transverse pumping. Fibres with different diameters such as 180, 460, 640 and 800 m were fabricated from a dye-doped hollow polymer preform. A blueshift in the mode structure was observed with decrease in fibre diameter leading to wide range tunability of the laser emission.

  8. 80-W cw TEM{sub 00} IR beam generation by use of a laser-diode-side-pumped Nd:YAG rod laser

    Energy Technology Data Exchange (ETDEWEB)

    Konno, Susumu; Fujikawa, Shuichi; Yasui, Koji [Mitsubishi Electric Corp. Amagasaki, Hyogo (Japan). Advanced Technology R and D Center

    1998-03-01

    We have demonstrated high-efficient and high-power operation of a diode-side-pumped Nd:YAG rod laser. The laser has a simple and scalable configuration consisting of a diffusive pumping reflector and an advanced cavity configuration for polarization-dependent bifocusing compensation. (author)

  9. Pulsed laser interference patterning of polyimide grating for dye-doped polymer laser

    Science.gov (United States)

    Kok, Soon Yie; Tou, Teck Yong; Yap, Seong Ling; Yap, Seong Shan

    2016-07-01

    Direct laser interference patterning of polyimide (PI) films was performed by using a pulsed 355-nm laser. At laser fluence of 0.4 J/cm2, gratings with spatial periods of 3.8 μm to 344 nm were created. The highest aspect ratio of the grating structure (0.8) was obtained for the 344-nm grating. An all-polymer dye laser was then fabricated by spin-coating a layer of disodium fluorescein (DF)-doped polyvinyl alcohol (PVA) film on bare and patterned PI substrate. Green laser emission was obtained when transversely pumped by a 355-nm laser. The lasing threshold reduced by ˜10 times for the sample with 344-nm grating while the laser intensity was ˜18 times higher. The enhancements are ascribed to the 344-nm grating structures, which act as an efficient distributed feedback resonator and distributed Bragg reflector grating for DF-doped PVA emitting at ˜563 nm, on top of being a passive light-trapping structures.

  10. Influence of absorbed pump profile on the temperature distribution within a diode side-pumped laser rod

    Indian Academy of Sciences (India)

    M H MOGHTADER DINDARLU; H TEHRANI M KAVOS; H SAGHAFIFAR; A MALEKI; GH SOLOOKINEJAD; M JABBARI

    2017-02-01

    In this paper, an analytical model for temperature distribution of the side-pumped laser rod is extracted. This model can be used for side-pumped laser rods whose absorbed pump profile is a Gaussian profile. Then, it is validated by numerical results which exhibit a good agreement with the analytical results. Afterwards, by considering a general expression for super-Gaussian and top-hat profiles, and solving the heat equation, the influence of profile width and super-Gaussian exponent of the profile on temperature distribution are investigated.Consequently, the profile width turns out to have a greater influence on the temperature compared to the type of the profile.

  11. Influence of absorbed pump profile on the temperature distribution within a diode side-pumped laser rod

    Science.gov (United States)

    Moghtader Dindarlu, M. H.; Tehrani, M. Kavosh; Saghafifar, H.; Maleki, A.; Solookinejad, Gh; Jabbari, M.

    2017-02-01

    In this paper, an analytical model for temperature distribution of the side-pumped laser rod is extracted. This model can be used for side-pumped laser rods whose absorbed pump profile is a Gaussian profile. Then, it is validated by numerical results which exhibit a good agreement with the analytical results. Afterwards, by considering a general expression for super-Gaussian and top-hat profiles, and solving the heat equation, the influence of profile width and super-Gaussian exponent of the profile on temperature distribution are investigated. Consequently, the profile width turns out to have a greater influence on the temperature compared to the type of the profile.

  12. Analysis of Thermal Effects in Laser Rod Pumped by Repetitively Pulsed Laser Diode Array

    Institute of Scientific and Technical Information of China (English)

    DAI Qin; LI Xin-zhong; WU Ri-na; WANG Xi-jun

    2007-01-01

    Based on some assumptions, the numerical model of thermal distribution in solid state laser crystal pumped by pulsed laser diode is set up due to the pumped intensity distribution. Taking into account the property of YAG materials that varies with temperature, the transient temperature distribution of the laser crystal is calculated using finite element method on condition that K is a constant and a function of temperature. Then, the influence of the pumping parameters on the thermal effect in laser crystal is also discussed. This study is helpful to optimize the design of the diode side pumped solid state lasers.

  13. Intracavity absorber effects in a CW dye laser. Progress report, June 1, 1978-May 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Brink, G.O.

    1979-02-01

    The technique of dye laser intercavity absorption is being studied as a possible method of detecting small densities of atoms and molecules in combustion systems. Two types of phenomena are observed. Absorption signals, which, although of complex line shape, result in a decrease in laser intensity at the absorption wavelength are observed over a wide range of absorber densities. At values of the pump laser power above a certain threshold an enhancement effect is observed in which the dye laser spectrally condenses at the absorber wavelength. The enhancement effect allows the detection of very low densities of sodium with good signal to noise ratio. The data obtained to date are discussed.

  14. Micro-Fluidic Dye Ring Laser - Experimental Tuning of the Wavelength and Numerical Simulation of the Cavity Modes

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Morten; Balslev, Søren; Mortensen, Niels Asger

    2006-01-01

    We demonstrate wavelength tuning of a micro-fluidic dye ring laser. Wavelength tunability is obtained by controlling the liquid dye concentration. The device performance is modelled by FEM simulations supporting a ray-tracing view.......We demonstrate wavelength tuning of a micro-fluidic dye ring laser. Wavelength tunability is obtained by controlling the liquid dye concentration. The device performance is modelled by FEM simulations supporting a ray-tracing view....

  15. Direct laser interference patterning of polystyrene films doped with azo dyes, using 355 nm laser light

    Energy Technology Data Exchange (ETDEWEB)

    Broglia, M.F. [Universidad Nacional de Río Cuarto, Departamento de Química, Ruta 36 km 601, Río Cuarto, Córdoba 5800 (Argentina); Saarland University, Department of Materials Science, Campus, D-66123 Saarbrücken (Germany); Suarez, S.; Soldera, F.; Mücklich, F. [Saarland University, Department of Materials Science, Campus, D-66123 Saarbrücken (Germany); Barbero, C.A.; Bellingeri, R.; Alustiza, F. [Universidad Nacional de Río Cuarto, Departamento de Química, Ruta 36 km 601, Río Cuarto, Córdoba 5800 (Argentina); Acevedo, D., E-mail: dacevedo@exa.unrc.edu.ar [Universidad Nacional de Río Cuarto, Departamento de Química, Ruta 36 km 601, Río Cuarto, Córdoba 5800 (Argentina)

    2014-05-01

    Highlights: • We describe the first use of Direct Laser Interference Patterning on PS at 355 nm. . • The structured areas of regular lines are produced in several square millimeters. • The method, Direct Laser Interference Patterning (DLIP) uses a single laser pulse. • DLIP is applied at room temperature and atmospheric pressure. • DLIP is easier to use than other lithographic techniques. • The topography contrasts with the usual Polystyrene ablation at lower wavelengths. - Abstract: The generation of line-like periodic patterns by direct laser interference patterning (DLIP) of polystyrene films (PS) at a wavelength of 355 nm has been investigated. No structuration is achieved in plain PS due to the weak absorption of the polymer at 355 nm. On the other hand, patterning is achieved on films doped (PSd) with an azo dye (2-anisidine → 2-anisidine) which is incorporated in the polymer solution used for film preparation. Periodic micro-structures are generated. DLIP on PSd results in the swelling of the surface at low fluences, while at high laser intensities it causes the ablation of the regions at the interference maxima positions. The results contrast with the usual process of DLIP on PS (at shorter wavelengths, like 266 nm) where only ablation is detected. The results suggest that decomposition of the azo dye is the driving force of the patterning which therefore differ from the patterning obtained when plain PS is irradiated with laser light able to be absorbed by the aromatic ring in PS (e.g. 266 nm). The biocompatibility of these materials and adhesion of cells was tested, the data from in vitro assays shows that fibroblast cells are attached and proliferate extensively on the PSd films.

  16. Molecular origins of optoelectronic properties in coumarin dyes: toward designer solar cell and laser applications.

    Science.gov (United States)

    Liu, Xiaogang; Cole, Jacqueline M; Waddell, Paul G; Lin, Tze-Chia; Radia, Jignesh; Zeidler, Anita

    2012-01-12

    Coumarin derivatives are used in a wide range of applications, such as dye-sensitized solar cells (DSCs) and dye lasers, and have therefore attracted considerable research interest. In order to understand the molecular origins of their optoelectronic properties, molecular structures for 29 coumarin laser dyes are statistically analyzed. To this end, data for 25 compounds were taken from the Cambridge Structural Database and compared with data for four new crystal structures of coumarin laser dyes [Coumarin 487 (C(19)H(23)NO(2)), Coumarin 498 (C(16)H(17)NO(4)S), Coumarin 510 (C(20)H(18)N(2)O(2)), and Coumarin 525 (C(22)H(18)N(2)O(3))], which are reported herein. The competing contributions of different resonance states to the bond lengths of the 4- and 7-substituted coumarin laser dyes are computed based on the harmonic oscillator stabilization energy model. Consequently, a positive correlation between the contribution of the para-quinoidal resonance state and the UV-vis peak absorption wavelength of these coumarins is revealed. Furthermore, the perturbations of optoelectronic properties, owing to chemical substituents in these coumarin laser dyes, are analyzed: it is found that their UV-vis peak absorption and lasing wavelengths experience a red shift, as the electron-donating strength of the 7-position substituent increases and/or the electron-withdrawing strength of the 3- or 4-position substituent rises; this conclusion is corroborated by quantum-chemical calculations. It is also revealed that the closer the relevant substituents align with the direction of the intramolecular charge transfer (ICT), the larger the spectral shifts and the higher the molar extinction coefficients of coumarin laser dyes. These findings are important for understanding the ICT mechanism in coumarins. Meanwhile, all structure-property correlations revealed herein will enable knowledge-based molecular design of coumarins for dye lasers and DSC applications.

  17. Random Laser Emission at Dual Wavelengths in a Donor-Acceptor Dye Mixture Solution

    CERN Document Server

    Kedia, Sunita

    2016-01-01

    The work was aimed to generate random laser emissions simultaneously at two wavelengths in a weakly scattering system containing mixture of binary dyes, rhodamine-B (Rh-B) and oxazine-170 (O-170) dispersed with ZnO nano-particles served as scattering centres. Random lasing performances for individual Rh-B dye were extensively studied for varying small signal gain/scatterer density and found lasing threshold significantly depend upon number density of dispersed nano-particles. In spite of inefficient pumping, we demonstrated possibility of random lasing in O-170 dye solution on account of resonance energy transfer from Rh-B dye served as donor. At optimum concentrations of fluorophores and scatterer in dye mixture solution, incoherent random lasing was effectively attained simultaneously at two wavelengths centered 90 nm apart. Dual-emission intensities, lasing thresholds and rate of amplifications were found to be equivalent for both donor and acceptor in dye mixture solution.

  18. Direct laser interference patterning of polystyrene films doped with azo dyes, using 355 nm laser light

    Science.gov (United States)

    Broglia, M. F.; Suarez, S.; Soldera, F.; Mücklich, F.; Barbero, C. A.; Bellingeri, R.; Alustiza, F.; Acevedo, D.

    2014-05-01

    The generation of line-like periodic patterns by direct laser interference patterning (DLIP) of polystyrene films (PS) at a wavelength of 355 nm has been investigated. No structuration is achieved in plain PS due to the weak absorption of the polymer at 355 nm. On the other hand, patterning is achieved on films doped (PSd) with an azo dye (2-anisidine → 2-anisidine) which is incorporated in the polymer solution used for film preparation. Periodic micro-structures are generated. DLIP on PSd results in the swelling of the surface at low fluences, while at high laser intensities it causes the ablation of the regions at the interference maxima positions. The results contrast with the usual process of DLIP on PS (at shorter wavelengths, like 266 nm) where only ablation is detected. The results suggest that decomposition of the azo dye is the driving force of the patterning which therefore differ from the patterning obtained when plain PS is irradiated with laser light able to be absorbed by the aromatic ring in PS (e.g. 266 nm). The biocompatibility of these materials and adhesion of cells was tested, the data from in vitro assays shows that fibroblast cells are attached and proliferate extensively on the PSd films.

  19. Q-switching and efficient harmonic generation from a single-mode LMA photonic bandgap rod fiber laser

    DEFF Research Database (Denmark)

    Laurila, Marko; Saby, Julien; Alkeskjold, Thomas T.;

    2011-01-01

    with a Mode-Field-Diameter (MFD) of 59 mu m. We further demonstrate high pulse energy Second-Harmonic-Generation (SHG) and Third Harmonic Generation (THG) using a simple Q-switched single-stage rod fiber laser cavity architecture reaching pulse energies up to 1mJ at 515nm and 0.5mJ at 343nm. (C) 2011 Optical......We demonstrate a Single-Mode (SM) Large-Mode-Area (LMA) ytterbium-doped PCF rod fiber laser with stable and close to diffraction limited beam quality with 110W output power. Distributed-Mode-Filtering (DMF) elements integrated in the cladding of the rod fiber provide a robust spatial mode...

  20. Q-switching and efficient harmonic generation from a single-mode LMA photonic bandgap rod fiber laser.

    Science.gov (United States)

    Laurila, Marko; Saby, Julien; Alkeskjold, Thomas T; Scolari, Lara; Cocquelin, Benjamin; Salin, Francois; Broeng, Jes; Lægsgaard, Jesper

    2011-05-23

    We demonstrate a Single-Mode (SM) Large-Mode-Area (LMA) ytterbium-doped PCF rod fiber laser with stable and close to diffraction limited beam quality with 110W output power. Distributed-Mode-Filtering (DMF) elements integrated in the cladding of the rod fiber provide a robust spatial mode with a Mode-Field-Diameter (MFD) of 59μm. We further demonstrate high pulse energy Second-Harmonic-Generation (SHG) and Third Harmonic Generation (THG) using a simple Q-switched single-stage rod fiber laser cavity architecture reaching pulse energies up to 1mJ at 515nm and 0.5mJ at 343nm.

  1. Deposition of organic dyes for dye-sensitized solar cell by using matrix-assisted pulsed laser evaporation

    Directory of Open Access Journals (Sweden)

    Chih-Ping Yen

    2016-08-01

    Full Text Available The deposition of various distinct organic dyes, including ruthenium complex N3, melanin nanoparticle (MNP, and porphyrin-based donor-π-acceptor dye YD2-o-C8, by using matrix-assisted pulsed laser evaporation (MAPLE for application to dye-sensitized solar cell (DSSC is investigated systematically. It is found that the two covalently-bonded organic molecules, i.e., MNP and YD2-o-C8, can be transferred from the frozen target to the substrate with maintained molecular integrity. In contrast, N3 disintegrates in the process, presumably due to the lower bonding strength of metal complex compared to covalent bond. With the method, DSSC using YD2-o-C8 is fabricated, and an energy conversion efficiency of 1.47% is attained. The issue of the low penetration depth of dyes deposited by MAPLE and the possible resolution to it are studied. This work demonstrates that MAPLE could be an alternative way for deposition of organic dyes for DSSC.

  2. Deposition of organic dyes for dye-sensitized solar cell by using matrix-assisted pulsed laser evaporation

    Science.gov (United States)

    Yen, Chih-Ping; Yu, Pin-Feng; Wang, Jyhpyng; Lin, Jiunn-Yuan; Chen, Yen-Mu; Chen, Szu-yuan

    2016-08-01

    The deposition of various distinct organic dyes, including ruthenium complex N3, melanin nanoparticle (MNP), and porphyrin-based donor-π-acceptor dye YD2-o-C8, by using matrix-assisted pulsed laser evaporation (MAPLE) for application to dye-sensitized solar cell (DSSC) is investigated systematically. It is found that the two covalently-bonded organic molecules, i.e., MNP and YD2-o-C8, can be transferred from the frozen target to the substrate with maintained molecular integrity. In contrast, N3 disintegrates in the process, presumably due to the lower bonding strength of metal complex compared to covalent bond. With the method, DSSC using YD2-o-C8 is fabricated, and an energy conversion efficiency of 1.47% is attained. The issue of the low penetration depth of dyes deposited by MAPLE and the possible resolution to it are studied. This work demonstrates that MAPLE could be an alternative way for deposition of organic dyes for DSSC.

  3. Deposition of organic dyes for dye-sensitized solar cell by using matrix-assisted pulsed laser evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Yen, Chih-Ping [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Yu, Pin-Feng [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Department of Physics, National Chung Cheng University, Chiayi 621, Taiwan (China); Wang, Jyhpyng [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Department of Physics, National Central University, Taoyuan 320, Taiwan (China); Lin, Jiunn-Yuan [Department of Physics, National Chung Cheng University, Chiayi 621, Taiwan (China); Chen, Yen-Mu [SuperbIN Co., Ltd., Taipei 114, Taiwan (China); Chen, Szu-yuan, E-mail: sychen@ltl.iams.sinica.edu.tw [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Department of Physics, National Central University, Taoyuan 320, Taiwan (China)

    2016-08-15

    The deposition of various distinct organic dyes, including ruthenium complex N3, melanin nanoparticle (MNP), and porphyrin-based donor-π-acceptor dye YD2-o-C8, by using matrix-assisted pulsed laser evaporation (MAPLE) for application to dye-sensitized solar cell (DSSC) is investigated systematically. It is found that the two covalently-bonded organic molecules, i.e., MNP and YD2-o-C8, can be transferred from the frozen target to the substrate with maintained molecular integrity. In contrast, N3 disintegrates in the process, presumably due to the lower bonding strength of metal complex compared to covalent bond. With the method, DSSC using YD2-o-C8 is fabricated, and an energy conversion efficiency of 1.47% is attained. The issue of the low penetration depth of dyes deposited by MAPLE and the possible resolution to it are studied. This work demonstrates that MAPLE could be an alternative way for deposition of organic dyes for DSSC.

  4. Low threshold and high efficiency solar-pumped laser with Fresnel lens and a grooved Nd:YAG rod

    Science.gov (United States)

    Guan, Zhe; Zhao, Changming; Yang, Suhui; Wang, Yu; Ke, Jieyao; Gao, Fengbin; Zhang, Haiyang

    2016-11-01

    Sunlight is considered as a new efficient source for direct optical-pumped solid state lasers. High-efficiency solar pumped lasers with low threshold power would be more promising than semiconductor lasers with large solar panel in space laser communication. Here we report a significant advance in solar-pumped laser threshold by pumping Nd:YAG rod with a grooved sidewall. Two-solar pumped laser setups are devised. In both cases, a Fresnel lens is used as the primary sunlight concentrator. Gold-plated conical cavity with a liquid light-guide lens is used as the secondary concentrator to further increase the solar energy concentration. In the first setup, solar pumping a 6mm diameter Nd:YAG rod, maximum laser power of 31.0W/m2 cw at 1064nm is produced, which is higher than the reported record, and the slope efficiency is 4.98% with the threshold power on the surface of Fresnel lens is 200 W. In the second setup, a 5 mm diameter laser rod output power is 29.8W/m2 with a slope efficiency of 4.3%. The threshold power of 102W is obtained, which is 49% lower than the former. Meanwhile, the theoretical calculating of the threshold power and slope efficiency of the solar-pumped laser has been established based on the rate-equation of a four-level system. The results of the finite element analysis by simulation software are verified in experiment. The optimization of the conical cavity by TraceProsoftware and the optimization of the laser resonator by LASCADare useful for the design of a miniaturization solar- pumped laser.

  5. Single-frequency operation of diode-pumped Nd YAG high-power lasers in rod and slab geometry

    CERN Document Server

    Knoke, S

    1998-01-01

    transverse and longitudinal mode is reduced by aberrations of the thermal lens, investigations in the compensation of the thermooptical effects by the laser crystal geometry and the resonator configuration were performed. In addition to the conventional cylindrical rod geometry slab laser crystals with a square cross-section and an internal zig-zag-pass were investigated. Based on the results, the output power of Nd:YAG lasers both in rod and slab geometry could be scaled to more than 20W in single-frequency operation for the first time. A maximum output power of up to 45W was demonstrated with a Nd:YAG rod laser system. Finally principal power limitations of these laser systems could be determined. Laser radiation of high coherence and with diffraction limited beam quality opens up many opportunities for applications in optic metrology, fundamental physics and nonlinear frequency conversion. Light sources with high single-frequency output powers are employed in large Michelson-type interferometers with armle...

  6. Optimized Distributed Feedback Dye Laser Sensor for Real-Time Monitoring of Small Molecule Diffusion

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Smith, Cameron; Dufva, Martin

    2014-01-01

    Nanoimprinted distributed feedback dye laser sensors featuring multilayer slab waveguides are presented. A simple yet precise analytical model is used to optimize the lasers in order to give highest sensitivity and it is found that the thickness of a high index TiO2 top layer is the most importan...

  7. QUANTITATIVE DETECTION OF ENVIRONMENTALLY IMPORTANT DYES USING DIODE LASER/FIBER-OPTIC RAMAN

    Science.gov (United States)

    A compact diode laser/fiber-optic Raman spectrometer is used for quantitative detection of environmentally important dyes. This system is based on diode laser excitation at 782 mm, fiber optic probe technology, an imaging spectrometer, and state-of-the-art scientific CCD camera. ...

  8. Micro-fabricated solid state dye lasers based on a photo-definable polymer

    DEFF Research Database (Denmark)

    Nilsson, Daniel; Balslev, Søren; Gregersen, Misha Marie

    2005-01-01

    We present a solid polymer dye laser based on a single-mode planar waveguide. The all-polymer device is self-contained in the photodefinable polymer SU-8 and may therefore easily be placed on any substrate and be integrated with polymer-based systems. We use as the active medium for the laser...

  9. Anionic and Zwitterionic Photophysical Effects in Some Pyridinium Oxazole Laser Dyes

    OpenAIRE

    Kubin, R. F.; Henry, R. A.; Pietrak, M. E.; Bliss, D. E.; Hall, J. H.

    1990-01-01

    Kauffman and Bentley [Laser Chem. 8, 49-59 (1988)] have reported increased laser output by changing the anion of certain pyridinium oxazole dyes from the tosylate to the mesylate salt. Likewise, zwitterion variants of these dyes are also reported to have a significantly improved laser output. We find anion changes to be modest and, with one exception, all zwitterions tested were no better or not as good as the tosylate salt with respect to lasing output. However, both the mesylate salt and th...

  10. Pulsed dye laser treatment of pigmented lesions: a randomized clinical pilot study comparison of 607- and 595-nm wavelength lasers.

    Science.gov (United States)

    Chern, Peggy L; Domankevitz, Yacov; Ross, E Victor

    2010-12-01

    The 595-nm pulsed dye laser has been used for the treatment of benign epidermal pigmented lesions (EPLs), but there is a risk of inducing undesirable purpura with treatment. To compare a 607-nm laser with a commercially-available 595-nm laser for the treatment of EPLs. Monte-Carlo simulations were performed to characterize laser interaction with skin. Ten patients with EPLs were treated with a 607-nm study prototype laser and the 595-nm pulsed dye laser twice at 2- to 4-week intervals on the left or right side on a randomized basis. Study endpoints included clearance rate of lesions, side effects immediately after treatment and at final follow-up, and patient discomfort/pain. Monte-Carlo simulations show that the 607-nm is absorbed more specifically by melanin than the 595-nm wavelength. Both lasers were effective in treatment of EPLs. The average degree of improvement overall was 41.2% with the 607-nm laser and 40% with the 595-nm laser. Patients reported less discomfort/pain during treatment with the 607-nm laser. Our findings suggest that the 607-nm laser is safe and at least as effective as the 595-nm laser in treatment of EPLs. There was less patient discomfort/pain during treatment using the 607-nm laser. Copyright © 2010 Wiley-Liss, Inc.

  11. Influence of ZnO nanoparticles on Coumarin-503 and Coumarin-540 dye mixture for energy transfer distributed feedback dye lasers

    Science.gov (United States)

    Vijayaraghavan, G. V.; Basheer Ahamed, M.

    2016-07-01

    Using organic dyes Coumarin-503 (C503) and Coumarin-540 (C540) as donor and acceptor dyes, respectively, and Nd-YAG as pumping source (355 nm), an energy transfer-distributed feedback dye laser (ETDFDL) was constructed and its characteristics studied. Theoretical studies such as critical transfer radius (Ro), critical concentration (Co), and half quenching concentration (C1/2) were carried out using the absorption and fluorescence spectra of donor and acceptor dyes. On varying the input pump energy to the nanoparticle-incorporated ETDFDL and keeping the acceptor and donor dye concentrations constant, the lasing output obtained was found to be higher than that without the use of nanoparticles. This enhancement was due to the size, shape, and coupling between nanoparticles with the dye mixture. Tunability in the range of 435-553 nm was obtained for both donor (C503) and acceptor (C540) DFDL as a function of the angle of interfering beams of the pump laser.

  12. Synchronous pumping of picosecond dye laser using high efficiency second harmonic generation from optical fibres

    Science.gov (United States)

    Lawandy, N. M.; Bernardin, J. P.; Macdonald, R. L.; Demouchy, G.

    1991-01-01

    The stable operation of a mode-locked dye laser synchronously pumped by the second harmonic of an Nd:YAG laser produced in an Nd codoped germanosilicate optical fiber is reported. The optical fiber preparation technique, which results in a second harmonic conversion efficiency of 2 percent, is described. This optical fiber SHG conversion efficiency is the highest reported to date using a continuous-wave mode-locked laser.

  13. Picosecond to femtosecond pulses from high power self mode-locked ytterbium rod-type fiber laser

    OpenAIRE

    Deslandes, Pierre; Perrin, Mathias; Saby, Julien; Sangla, Damien; Salin, François; Freysz, Eric

    2013-01-01

    International audience; We have designed an ytterbium rod-type fiber laser oscillator with tunable pulse duration. This system that delivers more than 10 W of average power is self mode-locked. It yields femtosecond to picosecond laser pulses at a repetition rate of 74 MHz. The pulse duration is adjusted by changing the spectral width of a band pass filter that is inserted in the laser cavity. Using volume Bragg gratings of 0.9 nm and 0.07 nm spectrum bandwidth, this oscillator delivers nearl...

  14. Spectral and generating properties of active laser media based on dye-doped elastomers

    Science.gov (United States)

    Bezrodnyi, Vladimir; Derevyanko, N.; Ishchenko, Alexander A.; Slobodin, Valeriy V.; Karabanova, Ludmila V.

    2002-12-01

    The advantages of a polyurethane matrix over other polymers, which are widely used as active media for dye lasers, are analzyed. This matrix exhibits the photostability, service life, radiation resistance, conversion efficiency, and homogeneity of the dye distribution that surpass these properties for active media based on polyurethane acrylate, which has close physical and operation properties. These advantages result not only from the milder polymerization conditions but also from a lower probability of the formation of ion pairs and dye aggregates. A substantial suppression of these processes in polyurethane is explained by its greater polarity and solvation ability compared to polyurathane acrylate.

  15. Tunable lasers in isotope separation: a colorful view of a dye chemist

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, P.R.

    1977-07-01

    Some of the problems to be encountered in the possible large scale use of dye lasers in an isotope separation plant are discussed.The effect of laser dye deterioration on performance is examined algebraically in terms of disappearance of dye molecules and the appearance of a new, single chemical product having absorption in the fluorescence band for a single pass through a transversely pumped amplifier. Loss of output, defined as ''quantum yield of laser deterioration'', Q/sub L/, is related to the true quantum yield of molecular destruction of the dye Q/sub M/, and other known parameters. 6-Diethylamino 3-keto fluoran, an example of an oxygen tricyclic merocyanine, is described. It was first reported in the pre-1900 German literature under the name of Chromogen Red B and it is an ineffective lasing dye on account of low fluorescence quantum yield. The techniques for measurement and the excited state absorption cross-sections are reported for the dyes rhodamine 6G fluoroborate in alcohol, rhodamine B basic solution in trifluoroethanol and kiton red S in trifluoroethanol.

  16. Laser induced photocatalytic degradation of hazardous dye (Safranin-O) using self synthesized nanocrystalline WO3.

    Science.gov (United States)

    Hayat, K; Gondal, M A; Khaled, M M; Yamani, Z H; Ahmed, S

    2011-02-28

    The photocatalytic degradation of Safranin-O (known as Basic Red 2) in water using locally synthesized nanocrystalline WO(3) as a photocatalyst was investigated under UV laser irradiation. The photo-oxidation removal of the dye was monitored by UV-vis spectrophotometer. The blank experiments for either laser irradiated only Safranin-O solution or the suspension containing WO(3) and Safranin-O in the dark showed that both laser illumination and the photocatalyst were essential for the removal of Safranin-O. The effect of experimental parameters including laser energy, catalyst loading, solution pH and the initial dye concentration on photocatalytic degradation of Basic Red 2 were also investigated. Results indicate that the rate of reaction is strongly influenced by the adsorption of an azo dye into the surface of the photocatalyst materials and suggests an optimum catalyst loading and dye concentration for the degradation reaction. It was investigated that the adsorption of the dye decreases at higher alkaline pH because both catalyst and substrate are negatively charged, developing repulsive forces between them. Kinetic data obtained reveals that the rate of the reaction obeys the first-order kinetics.

  17. Long-pulsed dye laser vs. intense pulsed light for the treatment of facial telangiectasias: a randomized controlled trial

    DEFF Research Database (Denmark)

    Nymann, Peter; Hedelund, Lene; Haedersdal, M

    2010-01-01

    This study aims to compare the efficacy and adverse effects of long-pulsed dye laser (LPDL) and intense pulsed light (IPL) in the treatment of facial telangiectasias.......This study aims to compare the efficacy and adverse effects of long-pulsed dye laser (LPDL) and intense pulsed light (IPL) in the treatment of facial telangiectasias....

  18. Refractometric monitoring of dissolution and fluid flow with distributed feedback dye laser sensor

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Sørensen, Kristian Tølbøl; Gade, Carsten

    2015-01-01

    Monitoring the dissolution of solid material in liquids and monitoring of fluid flow is of significant interest for applications in chemistry, food production, medicine, and especially in the fields of microfluidics and lab on a chip. Here, real-time refractometric monitoring of dissolution...... and fast fluid flow with DFB dye laser sensors with an optical imaging spectroscopy setup is presented. The dye laser sensors provide both low detection limits and high spatial resolution. It is demonstrated how the materials NaCl, sucrose, and bovine serum albumin show characteristic dissolution patterns...

  19. High frame rate multi-resonance imaging refractometry with distributed feedback dye laser sensor

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Dufva, Martin; Kristensen, Anders

    2015-01-01

    imaging refractometry without moving parts is presented. DFB dye lasers are low-cost and highly sensitive refractive index sensors. The unique multi-wavelength DFB laser structure presented here comprises several areas with different grating periods. Imaging in two dimensions of space is enabled...... by analyzing laser light from all areas in parallel with an imaging spectrometer. With this multi-resonance imaging refractometry method, the spatial position in one direction is identified from the horizontal, i.e., spectral position of the multiple laser lines which is obtained from the spectrometer charged...

  20. Method of targeted delivery of laser beam to isolated retinal rods by fiber optics.

    Science.gov (United States)

    Sim, Nigel; Bessarab, Dmitri; Jones, C Michael; Krivitsky, Leonid

    2011-11-01

    A method of controllable light delivery to retinal rod cells using an optical fiber is described. Photo-induced current of the living rod cells was measured with the suction electrode technique. The approach was tested with measurements relating the spatial distribution of the light intensity to photo-induced current. In addition, the ion current responses of rod cells to polarized light at two different orientation geometries of the cells were studied.

  1. Method of targeted delivery of laser beam to isolated retinal rods by fiber optics

    CERN Document Server

    Sim, Nigel; Jones, C Michael; Krivitsky, Leonid

    2013-01-01

    A method of controllable light delivery to retinal rod cells using an optical fiber is described. Photo-induced current of the living rod cells was measured with the suction electrode technique. The approach was tested with measurements relating the spatial distribution of the light intensity to photo-induced current. In addition, the ion current responses of rod cells to polarized light at two different orientation geometries of the cells were studied.

  2. The effect of pulsewidth of pumping pulse on the stability of distributed feedback dye laser

    Science.gov (United States)

    Pasandideh, K.; Rahbari, M.; Sadighi Bonabi, R.

    2017-04-01

    The generation of a single and stable picosecond pulse by distributed feedback dye laser is investigated in this work. The numerical result for the rate equation system that includes the thermal effects in the lasing medium is provided. By applying this model to Rhodamine 6G, it is found that considerable improvement in the stability of the laser can be achieved by pumping the system with narrower laser pulses. The simulation shows that if the dye solution is pumped by sub-200 ps pulse, the laser can be operated in single-pulse output mode with acceptable stability in pulsewidth over a long range of pumping intensity. This result is confirmed by a more complicated model composed of non-averaged Maxwell and rate equations. Even though the thermal effects do not play a significant role in equivalent cavity lifetime, they result in considerable wavelength shift toward the shorter wavelengths.

  3. Hair dryer use to optimize pulsed dye laser treatment in rosacea patients.

    Science.gov (United States)

    Kashlan, Lana; Graber, Emmy M; Arndt, Kenneth A

    2012-06-01

    Rosacea is a common chronic inflammatory condition characterized by erythema, telangiectasias, papules, and pustules. While there are many effective treatment options for the papulopustular type, laser therapy remains the most effective modality to treat erythematotelangiectatic rosacea. Erythema and flushing associated with rosacea remains an uncomfortable and socially embarrassing problem for patients. Unfortunately, patients often do not have significant erythema or flushing when they present for laser treatment. With this in mind, we propose a novel technique aimed at enhancing the response of rosacea patients being treated for erythema with pulsed dye laser. Specifically, we present a split-face example of our clinical observation that pre-treatment with forced heated air prior to pulsed-dye laser leads to a greater response in rosacea patients with erythema and flushing.

  4. A Polymer Film Dye Laser with Spatially Modulated Emission Controlled by Transversely Distributed Pumping

    Directory of Open Access Journals (Sweden)

    Zurab V. Wardosanidze

    2016-01-01

    Full Text Available Spatial modulation of laser emission controlled by the structure of excitation light field was demonstrated. A dye doped polymer film as an active medium was sandwiched between two laser mirrors forming a laser cell. The pumping was performed by an interference pattern formed with two mutually coherent beams of the second harmonic of a Q-switched Nd:YAG laser (532 nm and located in the plane of the laser cell. The laser emission was observed normally on the plane of the cell. The cross section of the obtained laser emission was modulated in intensity with an interval between maximums depending on the period of the pumping interference pattern. Thus, the emitted light field qualitatively looks like diffraction from an elementary dynamic hologram, that is, a holographic diffraction grating.

  5. High-speed off-axis holographic cinematography with a copper-vapor-pumped dye laser.

    Science.gov (United States)

    Lauterborn, W; Judt, A; Schmitz, E

    1993-01-01

    A series of coherent light pulses is generated by pumping a dye laser with the pulsed output of a copper-vapor laser at rates of as much as 20 kHz. Holograms are recorded at this pulse rate on a rotating holographic plate. This technique of high-speed holographic cinematography is demonstrated by viewing the bubble filaments that appear in water under the action of a sound field of high intensity.

  6. DNA-based dye lasers: progress in this half a decade

    Science.gov (United States)

    Kawabe, Yutaka

    2016-09-01

    After the invention of DNA-surfactant films and the proposal of dye doping into them by Ogata, many applications were demonstrated. Among them tunable thin film laser is one of the most attractive functional devices. Development and progress in DNA based lasers after the first observation of amplified spontaneous emission (ASE) by us has been reviewed in a former paper published in 2011.1 In this proceeding, progresses in the subsequent half a decade are described.

  7. Pulse propagation near zero group-velocity dispersion in a femtosecond dye laser.

    Science.gov (United States)

    Salin, F; Grangier, P; Georges, P; Brun, A

    1990-12-01

    The propagation of femtosecond pulses in a colliding-pulse mode-locked dye laser near zero group-velocity dispersion is studied. The pulse spectrum is shown to exhibit a double-peak structure. This structure and its dependence on the intracavity dispersion can be explained by nonlinear pulse propagation near zero dispersion. A value for the third-order dispersion of the laser cavity is deduced and is found to be predominant for pulses shorter than 50 fsec.

  8. High order operation of distributed feedback dye-doped sol-gel silica laser

    Institute of Scientific and Technical Information of China (English)

    Xiaolei Zhu(朱小磊); Dennis Lo(罗荫权)

    2003-01-01

    High order Bragg scattering (M = 2 and M = 3) operations of the distributed feedback dye dopedsol-gel silica lasers are achieved using the second harmonic output of a Nd:YAG laser as the pump. Laserlinewidth of less than 0.06 nm and conversion efficiency of 0.7% for M = 3 and 11% for M = 2 aremeasured. Wavelength tuning of about 15 nm around the emission center has been realized by varyingthe intersection angle.

  9. Morphological alterations on Citrobacter freundii bacteria induced by erythrosine dye and laser light.

    Science.gov (United States)

    Silva, Josmary R; Cardoso, Gleidson; Maciel, Rafael R G; de Souza, Nara C

    2015-01-01

    The effect of the laser irradiation (532 nm) on films prepared from Citrobacter freundii mixed with erythrosine dye was investigated by using atomic force microscopy. It was observed that morphological changes of bacterial surfaces after irradiations, which were attributed to cellular damage of the outer membranes, are a result of a photodynamic effect. The results suggested that the combination of erythrosine and laser light at 532 nm could be a candidate to a photodynamic therapy against C. freundii.

  10. Switchable random laser from dye-doped polymer dispersed liquid crystal waveguides

    NARCIS (Netherlands)

    Xiao, Shumin; Song, Qinghai; Wang, Feng; Liu, Liying; Liu, Jianhua; Xu, Lei

    2007-01-01

    A dye-doped polymer-dispersed liquid crystal (PDLC) film has been fabricated for random lasing action. In this PDLC film, the sizes of most liquid crystal (LC) droplets ranged from 200 to 500 nm. When the sample is optically pumped, ultrahigh Q (>10 000) lasing modes and a collimated laser beam can

  11. Independent tunability of the double-mode-locked cw dye laser.

    LENUS (Irish Health Repository)

    Bourkoff, E

    1979-06-01

    We report a new configuration that enables the double-mode-locked cw dye laser to be independently tunable. In addition, the output coupling at each of the two wavelengths can be independently specified. A series of oscillographs shows some interesting features unique to double mode locking and also shows the effects of varying the two cavity lengths with respect to each other.

  12. The efficacy of pulsed dye laser treatment for inflammatory skin diseases: A systematic review

    NARCIS (Netherlands)

    Erceg, A.; Jong, E.M.G.J. de; Kerkhof, P.C.M. van de; Seyger, M.M.B.

    2013-01-01

    BACKGROUND: The position of the pulsed dye laser (PDL) in the treatment of inflammatory skin diseases is still unclear. Evidence-based recommendations are lacking. OBJECTIVES: We sought to systematically review all available literature concerning PDL treatment for inflammatory skin diseases and to p

  13. Quantum beats in forward scattering: subnanosecond studies with a mode-locked dye laser.

    Science.gov (United States)

    Harde, H; Burggraf, H; Mlynek, J; Lange, W

    1981-06-01

    Time-resolved polarization spectroscopy of transient coherent superpositions of atomic substates is extended to the picosecond time scale by using a synchronously pumped mode-locked dye laser. As a first demonstration, hyperfine beats in the sodium D(1) and D(2), lines were resolved. The ground-state splitting could be determined with an accuracy of better than 10(-3).

  14. Quantum beats in forward scattering - Subnanosecond studies with a mode-locked dye laser

    Science.gov (United States)

    Harde, H.; Burggraf, H.; Mlynek, J.; Lange, W.

    1981-06-01

    Time-resolved polarization spectroscopy of transient coherent superpositions of atomic substates is extended to the picosecond time scale by using a synchronously pumped mode-locked dye laser. As a first demonstration, hyperfine beats in the sodium D1 and D2 lines were resolved. The ground-state splitting could be determined with an accuracy of better than 0.001.

  15. Diffusion driven optofluidic dye lasers encapsulated into polymer chips

    DEFF Research Database (Denmark)

    Wienhold, Tobias; Breithaupt, Felix; Vannahme, Christoph

    2012-01-01

    that these first order distributed feedback lasers can be operated for more than 90 min at a pulse repetition rate of 2 Hz without fluidic pumping. Ultra-high output pulse energies of more than 10 μJ and laser thresholds of 2 μJ are achieved for resonator lengths of 3 mm. By introducing comparatively large on...... of micro- and nanoscale structures into 100 μm foils simultaneously defines photonic resonators, liquid-core waveguides, and fluidic reservoirs. Subsequently, the fluidic structures are sealed with another 220 μm foil by thermal bonding. Tunability of laser output wavelengths over a spectral range of 24 nm...... on a single chip is accomplished by varying the laser grating period in steps of 2 nm. Low-cost manufacturing suitable for mass production, wide laser tunability, ultra-high output pulse energies, and long operation times without external fluidic pumping make these on-chip lasers suitable for a wide range...

  16. Detection of carcinogenic chromium in synthetic hair dyes using laser induced breakdown spectroscopy.

    Science.gov (United States)

    Gondal, M A; Maganda, Y W; Dastageer, M A; Al Adel, F F; Naqvi, A A; Qahtan, T F

    2014-03-10

    A laser induced breakdown spectroscopic (LIBS) system, consisting of a pulsed 266 nm laser radiation, in conjunction with a high-resolution spectrograph, a gated intensified charge coupled device camera, and a built-in delay generator were used to develop a sensitive detector to quantify the concentration of toxic substances such as chromium in synthetic hair dyes available on the local market. The strong atomic transition line of chromium (Cr I) at 427.5 nm wavelength was used as a fingerprint wavelength to calibrate the detection system and also to quantify the levels of chromium in the hair dye samples. The limit of detection achieved by our LIBS detection system for chromium was 1.2 ppm, which enabled us to detect chromium concentration in the range of 5-11 ppm in the commercial hair dyes available on the local market. The concentrations of chromium in the hair dyes measured using our system were validated using a standard analytical technique such as inductively coupled plasma mass spectrometry (ICPMS), and acceptable agreement (nearly 8%) was found between the results obtained by the two methods (LIBS and ICPMS). This study is highly significant for human health, specifically for people using synthetic hair dyes for changing the color of their hair.

  17. Spectroscopy and laser characterization of synthesized supramolecular host cucurbit[7]uril using aqueous Rhodamine B dye

    Indian Academy of Sciences (India)

    Deepak R Boraste; Monika Gupta; Ganapati Shankarling; Alok K Ray; Sandip K Nayak

    2014-02-01

    Recent demonstration in augmenting the efficiency of aqueous Rhodamine dye lasers using cucurbit[7]uril (CB[7]), a deaggregating and photostabilizing host, has drawn interest in the synthesis and characterization of spectroscopic grade CB[7] in larger quantities. Synthesis of cucurbituril group of macrocycles always leads to the formation of various homologues of CB[n]s (n=5–7) with CB[7] as the minor product. The literature procedure has been optimized to get pure CB[7] in 12–14% yield by fractional crystallization and the purity was checked by NMR, MS and spectrophotometric titration. Laser performances of the synthesized and commercial CB[7] sample as an additive were evaluated using Nd-YAG (532 nm) pumped Rhodamine B aqueous dye lasers and comparable results were obtained.

  18. Optical Features of Spherical Gold Nanoparticle-Doped Solid-State Dye Laser Medium

    Science.gov (United States)

    Hoa, D. Q.; Lien, N. T. H.; Duong, V. T. T.; Duong, V.; An, N. T. M.

    2016-05-01

    The development of a new laser medium based on gold nanoparticle/dye-doped polymethylmethacrylate (PMMA) has been investigated. In particular, gold nanoparticles with small (16 nm diameter) spherical shape strongly influenced the absorption and fluorescence emission spectra of [2-[2-[4-(dimethylamino)phenyl]ethenyl]-6-methyl-4 H-pyran-4-ylidene]-propanedinitrile (DCM) laser dye. Fluorescence quenching and enhancement of DCM emission were observed for various concentrations of gold nanoparticles (GNPs). Fluorescence intensity enhancement was recorded for the sample containing 1.5 × 1010 par/mL GNPs and doped with 3 × 10-5 mol/L DCM. Thermal photodegradation was significantly decreased by using low pump energy for laser emission.

  19. Direct analysis of textile fabrics and dyes using infrared matrix-assisted laser desorption electrospray ionization mass spectrometry.

    Science.gov (United States)

    Cochran, Kristin H; Barry, Jeremy A; Muddiman, David C; Hinks, David

    2013-01-15

    The forensic analysis of textile fibers uses a variety of techniques from microscopy to spectroscopy. One such technique that is often used to identify the dye(s) within the fiber is mass spectrometry (MS). In the traditional MS method, the dye must be extracted from the fabric and the dye components are separated by chromatography prior to mass spectrometric analysis. Direct analysis of the dye from the fabric allows the omission of the lengthy sample preparation involved in extraction, thereby significantly reducing the overall analysis time. Herein, a direct analysis of dyed textile fabric was performed using the infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) source for MS. In MALDESI, an IR laser with wavelength tuned to 2.94 μm is used to desorb the dye from the fabric sample with the aid of water as the matrix. The desorbed dye molecules are then postionized by electrospray ionization (ESI). A variety of dye classes were analyzed from various fabrics with little to no sample preparation allowing for the identification of the dye mass and in some cases the fiber polymer. Those dyes that were not detected using MALDESI were also not observed by direct infusion ESI of the dye standard.

  20. Polymer photonic crystal dye lasers as optofluidic cell sensors

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Lopacinska, Joanna M.; Jakobsen, Mogens Havsteen

    2009-01-01

    Hybrid polymer photonic crystal band-edge lasers are chemically activated to covalently bind bio-molecules or for HeLa cell attachment using an anthraquinone (AQ) UV activated photolinker. The lasers change emission wavelength linearly with inhomogeneous cell coverage....

  1. Solid State Dye Lasers Based on Coumarin 440 and Pyrromethene 567 Codoped Polymethyl Methacrylate

    Institute of Scientific and Technical Information of China (English)

    FAN Rong-Wei; LI Xiao-Hui; XIA Yuan-Qin; JIANG Yu-Gang; HE Wei-Ming; CHEN De-Ying

    2008-01-01

    Laser dye coumarin 440(C440) is codoped with pyrromethene 567 (PM567) into polymethyl methacrylate (PMMA ).The effects of C440 concentration on the performance of the solid state dye medium,including spectra property,slope efficiency and photostability,are studied.When C440 is codoped with PM567 at the same concentration 1 × 10-4 mol/L,the highest efficiency and photostability can be obtained.Compared with the medium based on pure PM567 doped PMMA,about 50% increase in slope efficiency and at least five-fold enhancement in the photostabifity are observed.

  2. Fast photocatalytic degradation of methylene blue dye using a low-power diode laser

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xianhua, E-mail: lxh@tju.edu.cn [School of Environmental Science and Engineering, Tianjin University, No. 92, Weijin Road, Nankai District, Tianjin 300072 (China); Yang, Yulou; Shi, Xiaoxuan [School of Environmental Science and Engineering, Tianjin University, No. 92, Weijin Road, Nankai District, Tianjin 300072 (China); Li, Kexun, E-mail: likx@nankai.edu.cn [School of Environmental Science and Engineering, Nankai University, Tianjin 300074 (China)

    2015-02-11

    Highlights: • Photocatalytic oxidation of methylene blue was studied under laser light irradiation. • Fast removal of methylene blue from aqueous solution was achieved. • The photocatalyst Ag/AgCl is efficient and stable under 443 nm laser light irritation. • Diode laser is a good light source for photocatalytic degradation of dyes. - Abstract: This study focused on the application of diode lasers as alternative light sources for the fast photocatalytic degradation of methylene blue. The photocatalytic decomposition of methylene blue in aqueous solution under 443 nm laser light irradiation was found to be technically feasible using Ag/AgCl nanoparticles as photocatalysts. The effects of various experimental parameters, such as irradiation time, light source, catalyst loading, initial dye concentration, pH, and laser energy on decolorization and degradation were investigated. The mineralization of methylene blue was confirmed by chemical oxygen demand analysis. The results demonstrate that the laser-induced photocatalytic process can effectively degrade methylene blue under the optimum conditions (pH 9.63, 4 mg/L MB concentration, and 1.4 g/L Ag/AgCl nanoparticles)

  3. Picosecond to femtosecond pulses from high power self mode-locked ytterbium rod-type fiber laser.

    Science.gov (United States)

    Deslandes, Pierre; Perrin, Mathias; Saby, Julien; Sangla, Damien; Salin, François; Freysz, Eric

    2013-05-06

    We have designed an ytterbium rod-type fiber laser oscillator with tunable pulse duration. This system that delivers more than 10 W of average power is self mode-locked. It yields femtosecond to picosecond laser pulses at a repetition rate of 74 MHz. The pulse duration is adjusted by changing the spectral width of a band pass filter that is inserted in the laser cavity. Using volume Bragg gratings of 0.9 nm and 0.07 nm spectrum bandwidth, this oscillator delivers nearly Fourier limited 2.8 ps and 18.5 ps pulses, respectively. With a 4 nm interference filter, one obtains picosecond pulses that have been externally dechirped down to 130 fs.

  4. Emission wavelength of multilayer distributed feedback dye lasers

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Smith, Cameron L. C.; Brøkner Christiansen, Mads;

    2012-01-01

    Precise emission wavelength modeling is essential for understanding and optimization of distributed feedback (DFB) lasers. An analytical approach for determining the emission wavelength based on setting the propagation constant of the Bragg condition and solving for the resulting slab waveguide...

  5. Improvements in laser flare removal for particle image velocimetry using fluorescent dye-doped particles

    Science.gov (United States)

    Petrosky, B. J.; Lowe, K. T.; Danehy, P. M.; Wohl, C. J.; Tiemsin, P. I.

    2015-11-01

    Laser flare, or scattering of laser light from a surface, can often be a major issue in particle image velocimetry (PIV) involving solid boundaries in the flow or a gas-liquid interface. The use of fluorescent light from dye-doped particles has been demonstrated in water applications, but reproducing the technique in an airflow is more difficult due to particle size constraints and safety concerns. The following work presents fluorescent Kiton Red 620 (KR620)-doped polystyrene latex microspheres as a solution to this issue. The particles are small and narrowly distributed, with a mean diameter of 0.87 μ \\text{m} and diameter distribution standard deviation of 0.30 μ \\text{m} . Furthermore, the KR620 dye exhibits much lower toxicity than other common fluorescent dyes, and would be safe to use in large flow facilities. The fluorescent signal from the particles is measured on average to be 320  ±  10 times weaker than the Mie scattering signal from the particles. This reduction in signal is counterbalanced by greatly enhanced contrast via optical rejection of the incident laser wavelength. Fluorescent PIV with these particles is shown to eliminate laser flare near surfaces, allowing for velocity measurements as close as 100 μ \\text{m} to the surface. In one case, fluorescent PIV led to velocity vector validation rates more than 20 times that of the Mie scattering results in the boundary layer region of an angled surface.

  6. High Efficiency Pulse Acetone Liquid Raman Laser Using DCM Fluorescent Dye as the Enhancement Medium

    Institute of Scientific and Technical Information of China (English)

    CHENG Andrew Yuk-Sun; YANG Jing-Guo; CHAN Mau-Hing

    2006-01-01

    Pumped by a frequency-doubled Nd:YAG laser, 10-Hz repetition rate, 320-mJ pump energy, and 5.1-ns pulse width, a liquid Raman laser using acetone as the Raman shifting medium has been established. The residual pump laser pulse and the generated Stokes pulse are directed to a DCM dye cell for energy enhancement of the Stokes pulse. The Raman laser system is capable to produce a laser pulse at wavelength 630 nm, with single pulse energy of 120 mJ, peak power of 70 MW and an average power of 1200 mW. The energy conversion efficiency is 37.5%, or equivalently a quantum efficiency of 44.5%.

  7. Nanoimprinted distributed feedback dye laser sensors for high frame rate refractometric imaging of dissolution and fluid flow

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Sørensen, Kristian Tølbøl; Gade, Carsten;

    2015-01-01

    High frame rate refractometric dissolution and fluid flow monitoring in one and two dimensions of space with distributed feedback dye laser sensors is presented. The sensors provide both low detection limits and high spatial resolution. © 2015 OSA.......High frame rate refractometric dissolution and fluid flow monitoring in one and two dimensions of space with distributed feedback dye laser sensors is presented. The sensors provide both low detection limits and high spatial resolution. © 2015 OSA....

  8. Long-pulsed dye laser versus long-pulsed dye laser-assisted photodynamic therapy for acne vulgaris: A randomized controlled trial

    DEFF Research Database (Denmark)

    Haedersdal, M.; Togsverd, K.; Wiegell, S.R.;

    2008-01-01

    Background: Long-pulsed dye laser (LPDL)-assisted photodynamic therapy has been suggested to be superior to laser alone for acne vulgaris but no evidence is available. Objective: To evaluate the efficacy and safety of LPDL alone versus LPDL in photodynamic therapy with methylaminolevulinic acid...... (MAL-LPDL) for acne vulgaris. Methods: Fifteen patients received a series of 3 full-face LPDL treatments and half-face prelaser MAL treatments; the latter being randomly assigned to the left or right side. Results: Inflammatory lesions were reduced more on MAL-LPDL-treated than on LPDL-treated sides...... to draw conclusions about the efficacy of the LPDL, only about the efficacy of MAL-LPDL compared with LPDL alone. Conclusions: MAL-LPDL is slightly superior to LPDL for the treatment of inflammatory acne Udgivelsesdato: 2008/3...

  9. Pyyromethene-BF2 Complexes as Laser Dyes

    Science.gov (United States)

    1990-05-24

    15 PAGE COUNT Interim Technical FROM6/01/89 TO5/31/9 21 May 1990 23 16. SUPPLEMENTARY NOTATION Submitted to Heteroatom Chemistry 17 COSATICODES 18...SUBJECT TERMS Continue on reverse of necessary ana identify oy blocK number) FIELD GROUP SUB-GROUP Laser action in pyrromethene-BF2 complexes, synthesis ...pyrromethene-BF2 complexes under flashlamp excitation showed broadband laser activity in the region . 530 - 580 nm. In methanol PMPDS-BF2 was six times more

  10. Refractometric monitoring of dissolution and fluid flow with distributed feedback dye laser sensor

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Sørensen, Kristian Tølbøl; Gade, Carsten;

    2015-01-01

    and fast fluid flow with DFB dye laser sensors with an optical imaging spectroscopy setup is presented. The dye laser sensors provide both low detection limits and high spatial resolution. It is demonstrated how the materials NaCl, sucrose, and bovine serum albumin show characteristic dissolution patterns......Monitoring the dissolution of solid material in liquids and monitoring of fluid flow is of significant interest for applications in chemistry, food production, medicine, and especially in the fields of microfluidics and lab on a chip. Here, real-time refractometric monitoring of dissolution....... The unique feature of the presented method is a high frame rate of up to 20 Hz, which is proven to enable the monitoring of fast flow of a sucrose solution jet into pure water. (C) 2015 Optical Society of America...

  11. Refractometric monitoring of dissolution and fluid flow with distributed feedback dye laser sensor.

    Science.gov (United States)

    Vannahme, Christoph; Sørensen, Kristian Tølbøl; Gade, Carsten; Dufva, Martin; Kristensen, Anders

    2015-03-09

    Monitoring the dissolution of solid material in liquids and monitoring of fluid flow is of significant interest for applications in chemistry, food production, medicine, and especially in the fields of microfluidics and lab on a chip. Here, real-time refractometric monitoring of dissolution and fast fluid flow with DFB dye laser sensors with an optical imaging spectroscopy setup is presented. The dye laser sensors provide both low detection limits and high spatial resolution. It is demonstrated how the materials NaCl, sucrose, and bovine serum albumin show characteristic dissolution patterns. The unique feature of the presented method is a high frame rate of up to 20 Hz, which is proven to enable the monitoring of fast flow of a sucrose solution jet into pure water.

  12. Single-mode solid-state polymer dye laser fabricated with standard I-line UV lithography

    DEFF Research Database (Denmark)

    Balslev, Søren; Mironov, Andrej; Nilsson, Daniel

    2005-01-01

    We present single-mode solid-state polymer dye lasers fabricated with standard UV lithography. The lasers use a high-order Bragg grating and rely on index-tuning of a photosensitive polymer for waveguiding. The gain medium is Rhodamine 6G.......We present single-mode solid-state polymer dye lasers fabricated with standard UV lithography. The lasers use a high-order Bragg grating and rely on index-tuning of a photosensitive polymer for waveguiding. The gain medium is Rhodamine 6G....

  13. Enhanced transduction of photonic crystal dye lasers for gas sensing via swelling polymer film

    DEFF Research Database (Denmark)

    Smith, Cameron; Lind, Johan Ulrik; Christiansen, Mads Brøkner;

    2011-01-01

    We present the enhanced transduction of a photonic crystal dye laser for gas sensing via deposition of an additional swelling polymer film. Device operation involves swelling of the polymer film during exposure to specific gases, leading to a change in total effective refractive index. Experimental...... in its application to other intracavity-based detection schemes to enable gas sensing. © 2011 Optical Society of America....

  14. Nonreciprocal phase shifts in a femtosecond dye laser.

    Science.gov (United States)

    Salin, F; Grangier, P; Georges, P; Saux, G L; Brun, A

    1990-08-15

    Beating is observed when the two output beams from a colliding-pulse mode-locked laser are recombined outside the cavity. This beating is attributed to nonlinear dephasing in the saturable absorber. An explanation in terms of the soliton period variation is given. The experimental results show good agreement with the predictions of the nonlinear Schrödinger equation.

  15. Transparent media characterization using sub-pico second dye laser

    CERN Document Server

    Lamy, F

    1982-01-01

    A new passively mode locked laser source developed at the Center for Laser Studies yielded pulses shorter than 0.14 ps, at a rate of 250 MHz or 0.3 ps pulses at a rate of 500 MHz. The laser and its modes of operation are described. With this source and a second order cross correlation technique similar to the autocorrelation used to determine the pulse duration, time domain reflectometry measurements can be made with a resolution of 40 mu m. Three dimensional images can be made by time resolving the backscattered radiation of a beam scanned through a medium. The depth resolution of 0.1 mu m can be carried over to the other two dimensions by computer reconstruction. The new technique should have important applications in medicine and biology. Because of the short duration of the laser pulses, high peak intensities can be used without damage to the tissues. Therefore, light measurements can be conducted through a larger depth than with continuous radiation.

  16. Laser-induced incandescence of suspended particles as a source of excitation of dye luminescence

    CERN Document Server

    Zelensky, S

    2003-01-01

    The interaction of pulsed YAG-Nd sup 3 sup + laser radiation with submicron light-absorbing particles suspended in an aqueous solution of Rhodamine 6G is investigated experimentally. The experiments demonstrate that the laser-induced incandescence of suspended particles excites the luminescence of the dissolved dye molecules. The mechanism of the luminescence excitation consists in the reabsorption of the thermal radiation within the volume of the sample cell. On the ground of this mechanism of excitation, a method of measurement of the luminescence quantum yield is proposed and realized. The method requires the knowledge of the geometrical parameters of the cell and does not require the use of reference samples.

  17. Reconfigurable Solid-state Dye-doped Polymer Ring Resonator Lasers

    Science.gov (United States)

    Chandrahalim, Hengky; Fan, Xudong

    2015-01-01

    This paper presents wavelength configurable on-chip solid-state ring lasers fabricated by a single-mask standard lithography. The single- and coupled-ring resonator hosts were fabricated on a fused-silica wafer and filled with 3,3′-Diethyloxacarbocyanine iodide (CY3), Rhodamine 6G (R6G), and 3,3′-Diethylthiadicarbocyanine iodide (CY5)-doped polymer as the reconfigurable gain media. The recorded lasing threshold was ~220 nJ/mm2 per pulse for the single-ring resonator laser with R6G, marking the lowest threshold shown by solid-state dye-doped polymer lasers fabricated with a standard lithography process on a chip. A single-mode lasing from a coupled-ring resonator system with the lasing threshold of ~360 nJ/mm2 per pulse was also demonstrated through the Vernier effect. The renewability of the dye-doped polymer was examined by removing and redepositing the dye-doped polymer on the same resonator hosts for multiple cycles. We recorded consistent emissions from the devices for all trials, suggesting the feasibility of employing this technology for numerous photonic and biochemical sensing applications that entail for sustainable, reconfigurable, and low lasing threshold coherent light sources on a chip. PMID:26674508

  18. Pulsed Dye Laser Therapy in the Treatment of Warts: A Review of the Literature.

    Science.gov (United States)

    Veitch, David; Kravvas, Georgios; Al-Niaimi, Firas

    2017-04-01

    Warts or verrucae vulgaris are common cutaneous infections with currently no definitive curative treatments available. To determine the efficacy of pulsed dye laser (PDL) in the treatment of warts. A literature search was performed using the PubMed and MEDLINE databases. A search using {(Wart[s], verruca or condylomata)} AND [(Pulsed dye laser)] was used. Forty-four articles were identified as relevant to this review. Simple warts were very responsive to PDL, being treated successfully in over 95% of patients. Facial and anogenital warts also demonstrated excellent outcomes. Recalcitrant warts, displayed significant variability in their response, ranging between 50% and 100% across all articles. The response rates seen in peripheral warts (involving the hands and feet) were also very variable, ranging between 48% and 95%. Recurrence rates at 4 months of follow-up were documented as 0% to 15%. Complications have been described as very few and rare, the main ones being topical discomfort and erythema. Pulsed dye laser is a safe and effective modality in the treatment of warts that can be applied to most body parts. Cost and availability remain a limitation to the use of PDL; however, this modality can be used when other more traditional and accessible treatments have failed.

  19. Diagnosis of NMOS DRAM functional performance as affected by a picosecond dye laser

    Science.gov (United States)

    Kim, Q.; Schwartz, H. R.; Edmonds, L. D.; Zoutendyk, J. A.

    1992-01-01

    A picosec pulsed dye laser beam was at selected wavelengths successfully used to simulate heavy-ion single-event effects (SEEs) in negative channel NMOS DRAMs. A DRAM was used to develop the test technique because bit-mapping capability and previous heavy-ion upset data were available. The present analysis is the first to establish such a correlation between laser and heavy-ion data for devices, such as the NMOS DRAM, where charge collection is dominated by long-range diffusion, which is controlled by carrier density at remote distances from a depletion region. In the latter case, penetration depth is an important parameter and is included in the present analysis. A single-pulse picosecond dye laser beam (1.5 microns diameter) focused onto a single cell component can upset a single memory cell; clusters of memory cell upsets (multiple errors) were observed when the laser energy was increased above the threshold energy. The multiple errors were analyzed as a function of the bias voltage and total energy of a single pulse. A diffusion model to distinguish the multiple upsets from the laser-induced charge agreed well with previously reported heavy ion data.

  20. Combined pulsed dye and CO2 lasers in the treatment of angiolymphoid hyperplasia with eosinophilia.

    Science.gov (United States)

    Sagi, Lior; Halachmi, Shlomit; Levi, Assi; Amitai, Dan Ben; Enk, Claes D; Lapidoth, Moshe

    2016-08-01

    Angiolymphoid hyperplasia with eosinophilia (ALHE) is an uncommon dermatosis of unknown etiology that manifests as characteristic red nodules and papules with a predilection for the scalp and periauricular region. Treatment is required for both esthetic and functional reasons, as lesions may ulcerate and bleed. Many treatment approaches have been reported, including excision, systemic medical approaches, topical or intralesional therapies, and non-invasive modalities including cryotherapy, electrosurgery, and laser. Treatments have exhibited variable efficacy, and the recurrence rate is 100 %. We report the combination of pulsed dye laser and CO2 laser in the treatment of ALHE in 14 patients. All patients exhibited clinical response after a mean of 2.4 ± 0.4 treatment sessions. The clinical efficacy of the combined treatment, together with its well-tolerated nature, render the use of pulsed dye laser in combination with CO2 laser, a viable treatment for debulking ALHE lesions. Ongoing maintenance treatments are needed to due to the high degree of relapse.

  1. Fast photocatalytic degradation of methylene blue dye using a low-power diode laser.

    Science.gov (United States)

    Liu, Xianhua; Yang, Yulou; Shi, Xiaoxuan; Li, Kexun

    2015-01-01

    This study focused on the application of diode lasers as alternative light sources for the fast photocatalytic degradation of methylene blue. The photocatalytic decomposition of methylene blue in aqueous solution under 443 nm laser light irradiation was found to be technically feasible using Ag/AgCl nanoparticles as photocatalysts. The effects of various experimental parameters, such as irradiation time, light source, catalyst loading, initial dye concentration, pH, and laser energy on decolorization and degradation were investigated. The mineralization of methylene blue was confirmed by chemical oxygen demand analysis. The results demonstrate that the laser-induced photocatalytic process can effectively degrade methylene blue under the optimum conditions (pH 9.63, 4 mg/L MB concentration, and 1.4 g/L Ag/AgCl nanoparticles). Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Photodissociation Dye Laser Studies and High Pressure Discharge Conditioning Studies

    Science.gov (United States)

    1976-11-01

    population in the lower laser level and that cryogenic operation will not be required. A simple rate-equation model (see Section II-D) of the photo... model shows that the steady-state population (Ds,) of excited singlet dimers is related to the population density of ground state dimers (Dg )• (DS...Tobe Deutchman disc capacitors connected In series. This energy Is then transferred by an EGG HY 3202 thyratron switch to a low Inductance transmission

  3. Selective photothermal interaction using near-infrared laser and laser-absorbing dye in gel phantom and chicken breast tissue

    Science.gov (United States)

    Cowan, Thomas M.; Liu, Guangyu; Simmons, Sarah; Real, Jeremy; Lucroy, Michael D.; Bartels, Kenneth E.; Nordquist, Robert E.; Chen, Wei R.

    2002-06-01

    Photothermal interaction of an 805-nm diode laser with an absorptive dye, indocyanine green (ICG), has been shown to be an efficacious therapy for metastatic breast tumors in a rat model when combined with immunoadjuvant. When ICG solution was injected into the target tissue, selective tissue destruction can be achieved. To study the selective photothermal interaction, temperature change in irradiated tissue was achieved. To study the selective photothermal interaction, temperature change in irradiated tissue was studied using chicken breast tissue and phantom composed of gelatin and intralipid. ICG solution was mixed with gel phantom to simulate dye-enhanced target tissue. The target gel was then embedded in chicken breast tissue. The temperature change of irradiated chicken and gel phantom was measured by needle temperature probes at different tissue depths and radii from the center of the laser beam to construct a two-dimensional array of temperature change in a cylindrical coordinate system. It was shown that it is possible to selectively raise the temperature of deep target tissue while not substantially heating nontargeted tissue. A Nd:YAG laser was also used to irradiate the tissue-gel system and the photothermal results were compared with that using the 805-nm laser.

  4. Photophysical characterization of pyrromethene 597 laser dye in cross-linked silicon-containing organic copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, A.; Agua, D. del [Institut II - Experimentelle und Angewandte Physik, Universitaet Regensburg, Universitaetsstrasse 31, 93053 Regensburg (Germany); Penzkofer, A. [Institut II - Experimentelle und Angewandte Physik, Universitaet Regensburg, Universitaetsstrasse 31, 93053 Regensburg (Germany)], E-mail: alfons.penzkofer@physik.uni-regensburg.de; Garcia, O.; Sastre, R. [Instituto de Ciencia y Tecnologia de Polimeros, CSIC, Juan de la Cierva 3, 28006 Madrid (Spain); Costela, A.; Garcia-Moreno, I. [Instituto de Quimica Fisica ' Rocasolano' , CSIC, Serrano 119, 28006 Madrid (Spain)

    2007-12-06

    Samples of the dipyrromethene-BF{sub 2} dye PM597 incorporated in copolymers of 3-trimethoxysilylpropyl 2-methylprop-2-enoate (TMSPMA, number of polymerizable CC double bonds: {kappa} = 1) with 2-(2-methylprop-2-enoyloxy)ethyl 2-methylprop-2-enoate (EGDMA, {kappa} = 2), [2-(hydroxymethyl)-3-prop-2-(prop-2-enoyloxymethyl)propyl] prop-2-enoate (PETA, {kappa} = 3), and [3-prop-2-enoyloxy-2,2-bis(prop-2-2-enoyloxymethyl)propyl]prop-2-enoate (PETRA, {kappa} = 4) are characterized. The fluorescence quantum distributions, fluorescence quantum yields, degrees of fluorescence polarization, and fluorescence lifetimes are measured. The radiative lifetimes are calculated from fluorescence lifetime and quantum yield. Absorption coefficient spectra are determined from transmission measurements. Absolute absorption cross-section spectra and dye concentrations are obtained by calibration to the radiative lifetimes and to saturable absorptions. Excited-state absorption cross-sections at 527 nm are determined by saturable absorption measurements. The photo-degradation is studied under cw laser excitation conditions and quantum yields of photo-degradation are extracted. The excited-state absorption cross-sections were found to be rather small, and the photo-stability turned out to be high (up to 3 million excitation cycles before degradation) making this class of dipyrromethene dye-doped polymers attractive active laser media. Structural and thermo-mechanical properties of the materials have been determined by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetry, densitometry, and refractometry. They improve with increasing inter-crossing (copolymerization of TMSPMA with PETA and PETRA). The laser properties of the PM597 doped copolymers were evaluated by transverse pumping with 6 ns laser pulses at 532 nm. The best laser materials resulted to be the 7:3 and 9:1 TMSPMA-monomer copolymers.

  5. Combined pulsed dye laser and fiberoptic Nd-YAG laser for the treatment of hypertrophic port wine stain.

    Science.gov (United States)

    Radmanesh, Mohammed; Radmanesh, Ramin

    2017-10-01

    The hypertrophic Port Wine Stain (PWS) is only partially and superficially treated with the Pulsed dye laser (PDL) because of its limited depth of penetration. We used combined PDL and fiberoptic 1444-nm Nd-YAG laser to treat a case with hypertrophic PWS. After tumescent anesthesia, few holes were made by a 16-gauge needle on different sides of the lesion. The fiberoptic tip of 1444-nm Nd-YAG laser was inserted within the holes and was pushed forward while triggering. In a fan pattern and by a back and forth movement, the subcutaneous and deep dermal areas were coagulated. The skin and outer mucosal surfaces were then treated by PDL. The fiberoptic system used was Accusculpt 1444-nm Nd-YAG laser (Lutronic lasers, South Korea), and the PDL used was 585 nm Nlite system (Chromogenex UK). The parameters used for PDL were fluence = 9 Joules/cm(2) and the spot size was 5 mm. The parameters used for fiberoptic 1444-nm Nd-YAG laser were: Pulse rate = 30 Hz, pulse energy = 300 mJ, power = 6 W, and the total energy = 4000 J for the whole face and mucosa. Little sign of regression and moderate purpura were detected immediately after combined fiberoptic Nd-YAG and PDL therapy. The lesion gradually regressed within 4 months with satisfactory color and volume change. Combined fiberoptic Nd-YAG laser and PDL can be used for the treatment of deeper and superficial layers of hypertrophic PWS.

  6. Nd:YAG (2 omega) pumped dye laser using self-filtering unstable resonator

    CERN Document Server

    Rahimian, K; Hariri, H

    2002-01-01

    A self-filtering unstable resonator with a magnification of M=-3 in a Nd:YAG (2 omega) dye laser has been studied. The dye solution is Rhodamine 6 G in alcohol with the concentration of 5*10 sub - 3 Mol/lit. The spatial intensity distribution of the resonator has been compared has been compared with that of a plane-parallel resonator of equal length. The output energy in both configurations are comparable (20 mu J ,and 26 mu J ,respectively). A significant difference between these two resonators is the laser beam divergence, where beam divergences of 0.77 mrad for the self-filtering unstable resonator and 1.6 mrad for the plane-parallel resonator have been measured. The brightness corresponding to these two resonators are 1.5* 10 sub 1 1 and 2.2* 10 sub 1 0W.cm sub - 2.Sr sub - 1, and the pulse widths are 7 and 17 ns, respectively. These figures show clearly that laser resonator based on the self-filtering unstable resonator design an increase the laser brightness a factor of 10, with a beam divergence of a f...

  7. Effect Of Free Radical Quenchers On Dye-Mediated Laser Light Induced Photosensitization Of Leukemic Cells

    Science.gov (United States)

    Gulliya, Kirpal S.; Matthews, James L.; Fay, Joseph W.; Dowben, Robert M.

    1988-02-01

    The effect of free radical quenchers (ascorbate, catalase, and mannitol) on merocyanine 540 (MC540) mediated, laser light induced photolysis of human acute promyelocytic leukemia cell line (HL-60) was investigated. Results show that in the presence of human albumin (0.25%), dye-mediated (2014/m1), laser light induced photolysis of leukemic cells resulted in a 99.9999% cell kill. Seventy percent of the normal bone marrow cells survived the treatment. The addition of free radical quenchers prior to laser irradiation procedure increases the HL-60 cell survival. Increases of 5.5% and 4.4%, respectively, were observed in the presence of catalase and ascorbate or mannitol. In the presence of a mixture of catalase and mannitol or catalase and ascorbate, this increase in viability was not observed. However, the viability of normal bone marrow cells under these conditions also decreased from 70% to 63%. These findings may be useful in ex-vivo bone marrow purging.

  8. An Axisymmetric Numerical Model for Simulating Kinetically-Limited Growth of a Cylindrical Rod in 3D Laser-induced Chemical Vapor Deposition

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Laser-induced chemical vapor deposition (LCVD) is an important process for freeform microfabrication of high aspect ratio prototypes. The system consists of a laser beam focused onto a movable substrate in a vacuum chamber.Heat from the laser at or near the focal spot of the beam causes gas in the chamber to react. As a result, solidphase reaction products are deposited on the substrate to form the microstructure. In this paper, we develop a numerical model for simulating growth of an axisymmetric cylindrical rod by pre-specifying the surface temperatures required for growing the rod and then by solving for the laser power that satisfies the pre-specified temperatures.The solution using least squares is obtained by minimizing the sum of square deviations between the pre-specified surface temperatures and the calculated temperatures from the heat equation with a given laser power as a heat source. Model predictions of the laser power over growth time helped in optimizing the growth process. Rods grown based on the predicted laser power from the numerical model were very close to being cylindrical in shape. Ways to further improve the model are being investigated.

  9. Micellar Electrokinetic Chromatography with Laser-Induced Fluorescence Detection for Separation of Red and Yellow Historical Dyes

    Directory of Open Access Journals (Sweden)

    Shokoufeh Ahmadi

    2013-03-01

    Full Text Available In this study, the separation parameters in micellar electrokinetic chromatography (MEKC-laser-induced fluorescence (LIF were optimized for the separation of red and yellow historical dyes in 20 mM borate buffer with 20 mM sodium dodecyl sulfate (SDS. Separation conditions were optimized by changing pH, organic modifier (methanol and acetonitrile concentrations and applied voltage. The mixtures of dyes used in this study included four anthraquinone dyes (alizarin, purpurin, emodin and carmine and six flavonoid dyes (luteolin, apigenin, kaempferol, quercetin, morin and myricetin. For this work, dyes were introduced electro-kinetically (10 kV for 5 s into a 50 cm capillary (10 µm id and separated using a running potential of 18, 20, 22 and 25 kV. Absolute limits of detection for most of these dyes was less than 1 pg. For dyes such as alizarin, improved detection limits were achieved at pH = 9.24; however dyes such as purpurin had significantly improved detection limits at pH = 8.0. The successful extraction and identification of a number of dyes in plants and textiles samples is also described.

  10. Application of highly sensitive fluorescent dyes (CyDye DIGE Fluor saturation dyes) to laser microdissection and two-dimensional difference gel electrophoresis (2D-DIGE) for cancer proteomics.

    Science.gov (United States)

    Kondo, Tadashi; Hirohashi, Setsuo

    2006-01-01

    Proteome data combined with histopathological information provides important, novel clues for understanding cancer biology and reveals candidates for tumor markers and therapeutic targets. We have established an application of a highly sensitive fluorescent dye (CyDye DIGE Fluor saturation dye), developed for two-dimensional difference gel electrophoresis (2D-DIGE), to the labeling of proteins extracted from laser microdissected tissues. The use of the dye dramatically decreases the protein amount and, in turn, the number of cells required for 2D-DIGE; the cells obtained from a 1 mm2 area of an 8-12 microm thick tissue section generate up to 5,000 protein spots in a large-format 2D gel. This protocol allows the execution of large-scale proteomics in a more efficient, accurate and reproducible way. The protocol can be used to examine a single sample in 5 d or to examine hundreds of samples in large-scale proteomics.

  11. Enhancement of p-polarized output power in long pulse single rod Nd:YAG laser using a tilted 90° quartz rotator

    Science.gov (United States)

    Choubey, Ambar; Mondal, Shyamal; Singh, Ravindra; Upadhyaya, B. N.; Datta, P. K.; Oak, S. M.

    2014-11-01

    We report a study on the enhancement of linearly p-polarized output power in long pulse (2-20 ms) multimode operation of single rod Nd:YAG laser. Laser resonator was designed using a simple optical scheme with a tilted 90° quartz rotator and a re-entering feedback mirror placed at appropriate location. A p-polarized average output power of 215 W has been achieved with a slope efficiency of 4.5%, which is on higher side for a typical long pulse single rod Nd:YAG laser system. It has been verified experimentally that the depolarization losses can be reduced significantly from a value of ~34% to ~9%. Further, this scheme has resulted in a significant enhancement (more than 80%) of p-polarized output power as compared to placing a polarizer in the resonator. This long pulse p-polarized laser will be useful in various material processing applications and nonlinear frequency conversions.

  12. High-intensity coherent vacuum ultraviolet source using unfocussed commercial dye lasers.

    Science.gov (United States)

    Albert, Daniel R; Proctor, David L; Davis, H Floyd

    2013-06-01

    Using two or three commercial pulsed nanosecond dye lasers pumped by a single 30 Hz Nd:YAG laser, generation of 0.10 mJ pulses at 125 nm (6 × 10(13) photons∕pulse) has been demonstrated by resonance enhanced four-wave mixing of collimated (unfocussed) laser beams in mercury (Hg) vapor. Phase matching at various vacuum ultraviolet (VUV) wavelengths is achieved by tuning one laser in the vicinity of the 6 (1)S0 → 6 (3)P1 resonance near 253.1 nm. A number of different mixing schemes are characterized. Our observations using broadband lasers (~0.15 cm(-1) bandwidths) are compared to previous calculations pertaining to four-wave mixing of low intensity narrowband laser beams. Prospects for further increases in pulse energies are discussed. We find that VUV tuning curves and intensities are in good agreement with theoretical predictions. The utility of the VUV light source is demonstrated by "soft universal" single-photon VUV ionization in crossed molecular beam studies and for generation of light at 130.2 nm for oxygen atom Rydberg time-of-flight experiments.

  13. A Fast and in-Situ Measuring Method Using Laser Triangulation Sensors for the Parameters of the Connecting Rod.

    Science.gov (United States)

    Li, Xing-Qiang; Wang, Zhong; Fu, Lu-Hua

    2016-10-12

    The connecting rod is a critical part inside the marine engine. The inspection of its important parameters is directly related to the assembly and quality of the marine engine. A coordinate measuring machine (CMM) is a conventional choice to measure the parameters of a connecting rod. However, CMM requires significant resources in time and cost, which leads researchers into in-situ measurement. This article presents a fast and in-situ measuring method by using a laser-based measuring head. Two measuring strategies are adopted in the inspection process. For positional measurements (such as the hole-center distance), whose accuracy requirement is generally low, the coordinate system of the numerical control (NC) machine is combined with the measuring head to acquire the positional parameters. For dimensional measurements (such as inner diameters), whose accuracy requirement is rather high, the NC machine is used just as transportation. Note that the measuring head has the ability to perform the dimension inspection independently. The accuracy of the measuring head is high enough to meet the dimensional accuracy requirements. Experiments are performed to validate the proposed method. The measuring error of the inner diameters is from 5 μm to 7 μm. The measuring error of hole-center distance is within 15 μm. The measurement of all these parameters can be done within 1 min.

  14. Unconventional High-Performance Laser Protection System Based on Dichroic Dye-Doped Cholesteric Liquid Crystals

    Science.gov (United States)

    Zhang, Wanshu; Zhang, Lanying; Liang, Xiao; Le Zhou; Xiao, Jiumei; Yu, Li; Li, Fasheng; Cao, Hui; Li, Kexuan; Yang, Zhou; Yang, Huai

    2017-01-01

    High-performance and cost-effective laser protection system is of crucial importance for the rapid advance of lasers in military and civilian fields leading to severe damages of human eyes and sensitive optical devices. However, it is crucially hindered by the angle-dependent protective effect and the complex preparation process. Here we demonstrate that angle-independence, good processibility, wavelength tunability, high optical density and good visibility can be effectuated simultaneously, by embedding dichroic anthraquinone dyes in a cholesteric liquid crystal matrix. More significantly, unconventional two-dimensional parabolic protection behavior is reported for the first time that in stark contrast to the existing protection systems, the overall parabolic protection behavior enables protective effect to increase with incident angles, hence providing omnibearing high-performance protection. The protective effect is controllable by dye concentration, LC cell thickness and CLC reflection efficiency, and the system can be made flexible enabling applications in flexible and even wearable protection devices. This research creates a promising avenue for the high-performance and cost-effective laser protection, and may foster the development of optical applications such as solar concentrators, car explosion-proof membrane, smart windows and polarizers. PMID:28230153

  15. Use of reflectance spectrophotometry to predict the response of port wine stains to pulsed dye laser.

    Science.gov (United States)

    Halachmi, Shlomit; Azaria, Ron; Inbar, Roy; Ad-El, Dean; Lapidoth, Moshe

    2014-01-01

    Reflectance spectroscopy can be used to quantitate subtle differences in color. We applied a portable reflectance spectrometer to determine its utility in the evaluation of pulsed dye laser treatment of port wine stains (PWS) and in prediction of clinical outcome, in a prospective study. Forty-eight patients with PWS underwent one to nine pulsed dye laser treatments. Patient age and skin color as well as PWS surface area, anatomic location, and color were recorded. Pretreatment spectrophotometric measurements were performed. The subjective clinical results of treatment and the quantitative spectrophotometry results were evaluated by two independent teams, and the findings were correlated. The impact of the clinical characteristics on the response to treatment was assessed as well. Patients with excellent to good clinical results of laser treatments had pretreatment spectrophotometric measurements which differed by more than 10%, whereas patients with fair to poor results had spectrophotometric measurements with a difference of of less than 10%. The correlation between the spectrophotometric results and the clinical outcome was 73% (p Spectrophotometry has a higher correlation with clinical outcome and a better predictive value than other nonmeasurable, nonquantitative, dependent variables.

  16. Recording sub-picosecond pulses in emission from neodymium dye lasers

    Energy Technology Data Exchange (ETDEWEB)

    Brekhov, O.M.; Lebedev, V.B.; Luzanov, V.B.; Maranichenko, N.I.; Prokhorenko, V.I.; Stepanov, B.M.; Tikhonov, E.A.

    1981-01-01

    Using the ''Agent-04M'' experimental optico -electronic camera, the sub-picosecond fluctuation structure at the output of a neodymium laser is recorded. The laser consists of a master oscillator whose non-dispersive resonator uses a tray containing 3274-M dye for passive mode locking, a system for isolating a single 8 to 25 picosecond pulse from the pulse train, and a five-stage amplifier with an output power of 1 gigawatt. The minimum duration of the substructure pulses, detected by the camera wtih a contrast of greater than or equal to 40%, does not exceed .3 picoseconds. The total width of the emission spectrum at the output of this amplifier is 9 nanometers, which in the hypothesis on the Gaussian shape of the pulses corresponds to their minimum duration of 2 picoseconds. The emission from the power amplifier is used to pump a superfluorescence 6zh rhodamine dye laser. Here the pulse duration is measured using both a camera and an autocorrelation method.

  17. Analysis of thermal distribution in two end pumping Nd:YAG laser rod using bacterial foraging optimization algorithm

    Indian Academy of Sciences (India)

    Mohammed A Minshed

    2013-03-01

    There is a strong need for the optimized management of the thermal problem in Nd:YAG laser rod and for a powerful, fast, and accurate modelling tool capable of treating the heat source distribution very close to what it actually is. In this paper, a new optimization algorithm called bacterial foraging optimization algorithm (BFOA) is proposed for simulation of the radial heat distribution. A BFOA discloses a simulation method which delivers the exact temperature distribution in a circularly cylindrical structure with a circularly symmetrical, longitudinally, and transversally non-uniform heat source distribution and circularly symmetrical cooling means. The output power is obtained and compared with previously published experimental measurements for different pump power and a good agreement has been found.

  18. [Combination of pulsed dye laser and propranolol in the treatment of ulcerated infantile haemangioma].

    Science.gov (United States)

    Rodríguez-Ruiz, M; Tellado, M G; del Pozo Losada, J

    2016-02-01

    Ulceration is the most common complication of infantile haemangioma, with 15.8% of them usually appearing in the proliferative phase. They can be managed in several ways. We present our experience in the treatment of ulcerated haemangioma with the combination of pulsed dye laser and propranolol. A retrospective observational study was conducted on patients with ulcerated infantile haemangioma treated with pulsed dye laser in association with propranolol. The study included 7 patients, 3 cases in labial area and 4 cases in the nappy area. A review was also performed on a historical cohort of 5 children with ulcerated haemangiomas with the same features, but treated only with propranolol, topical agents and occlusive dressings. The median size of the ulcer was 1.0 cm, and there was a mean time of onset pre-treatment of 2 weeks. Pain and bleeding was present in all patients. After 2 weeks of combined propranolol and laser treatment, all lesions were healed. The pain disappeared after the first laser session. Patients with ulcerative haemangioma in the labial area obtained a better response than patients with haemangioma in the nappy area. The cohort of patients treated with propranolol required a mean healing time of 5.2 weeks, with the addition of an occlusive dressing with ointment. We believe that our results suggest that combined treatment, laser and propranolol, has synergistic effects that accelerate the healing of ulcerated haemangioma, as observed in our patients. Further studies with larger numbers of patients are needed to confirm this fact. Copyright © 2015 Asociación Española de Pediatría. Published by Elsevier España, S.L.U. All rights reserved.

  19. Photonic integration in k-space: Enhancing the performance of photonic crystal dye lasers

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Kristensen, Anders; Xiao, Sanshui

    2008-01-01

    We demonstrate how two optical functionalities can be implemented in a single photonic crystal structure by carefully engineering dispersion in several different bands at several different wavelengths. We use the concept for optically pumped dye doped hybrid polymer band edge lasers and show how...... a rectangular photonic crystal lattice imprinted into the surface can provide both feedback for in-plane band edge lasing and couple pump light into the device plane, thus increasing the emitted intensity and lowering the lasing threshold by more than an order of magnitude....

  20. Absorption spectroscopy measurements in optically dense explosive fireballs using a modeless broadband dye laser.

    Science.gov (United States)

    Glumac, Nick

    2009-09-01

    A modeless broadband dye laser is applied to probe inside optically dense fireballs generated by high explosives using single-shot, high resolution absorption spectroscopy. Despite attenuation of the main beam by 98%, high signal-to-noise ratio absorption spectra of Al, Ti, and AlO are readily obtained at resolutions of 0.007 nm, and luminosity from the fireball is strongly rejected. Detection limits for atomic species are less than 200 ppb. The method offers good time resolution of chemistry within the fireball, and scaling laws suggest that this technique should be valid in explosives tests at least up to the gram scale.

  1. A review of the quality of life following pulsed dye laser treatment for erythemotelangiectatic rosacea.

    Science.gov (United States)

    Bonsall, Alexandra; Rajpara, Sanjaykumar

    2016-01-01

    Rosacea is a chronic condition, affecting up to 10% of the population. It has a negative impact on patients' quality of life (QOL), leading to loss of self-confidence, emotional distress and withdrawal from normal societal interactions. Erythemotelangiectatic (ET) rosacea is a frequent reason for consultation and difficult to treat, as vascular signs such as flushing, erythema and telangiectasia often persist despite medical therapy. Several studies have demonstrated objective improvements in vascular signs following pulsed dye laser (PDL) treatment, but very few have investigated improvement in QOL. We reviewed the current literature to find evidence for the effect of PDL on QOL in ET rosacea.

  2. Pulsed dye laser versus long pulsed Nd:YAG laser in the treatment of angiokeratoma of Fordyce: A randomized, comparative, observer-blinded study.

    Science.gov (United States)

    Ibrahim, S M

    2016-01-01

    Angiokeratoma of Fordyce is typically asymptomatic, blue-to-red papules with a scaly surface located on the scrotum, shaft of penis or labia majora. They can be treated with some locally destructive treatment modalities such as excision, electrocoagulation, cryotherapy and laser. To compare the effects of the pulsed dye laser versus long pulsed Nd:YAG laser in the treatment of angiokeratoma of Fordyce. Twenty tow patients with angiokeratoma of Fordyce were included in this study. All participants received three sessions of pulsed dye laser on the selected side or part of lesional area and long pulsed Nd:YAG laser on the other side or part of lesional area. Two dermatologists independently evaluated the photographs of the baseline and two-month follow-up after last session using a grade system in which treatment response was categorized into six grades. Both PDL and long pulsed Nd:YAG laser revealed statistically significant improvements in angiokeratoma of fordyce. Comparatively, there was a statistical difference between them (overall mean improvement with PDL, 61.8%, versus Nd:YAG, 77.63%; p laser are effective and safe in the treatment of angiokeratoma of Fordyce with better response in Nd:YAG laser than pulsed dye laser.

  3. Photophysical Parameters, Excitation Energy Transfer, and Photoreactivity of 1,4-Bis(5-phenyl-2-oxazolylbenzene (POPOP Laser Dye

    Directory of Open Access Journals (Sweden)

    Samy A. El-Daly

    2012-01-01

    Full Text Available The effect of solvents on the absorption and emission spectra of 1,4-bis(5-phenyl-2-oxazolylbenzene (POPOP laser dye has been studied in various solvents at 298 K. A bathochromic shift was observed in absorption and fluorescence spectra upon increase of solvent polarity, which indicates that this transition is π-∗. The ground and excited state dipole moments were calculated as 2.23 and 6.34 Debye, respectively. The dye solution in MeOH, n-heptane, and methyl isobutyl ketone gives laser emission in the blue region upon excitation by a 337.1 nm nitrogen pulse; the gain coefficient and emission cross section as well as normalized photostability have been determined. Excitation energy transfer from POPOP to rhodamine B and fluorescine was studied to improve the laser emission from these dyes. Such an energy transfer dye laser system (ETDL obeys a long range columbic energy transfer mechanism with a critical transfer distance, R0, of 25 and 33 Å and kq equal to 10.4×1012 and 26.2×1012M−1s−1 for the POPOP/RB and POPOP/fluorescine pair, respectively. The POPOP dye is highly photostable in polar protic and polar aprotic solvents, while it displays photodecomposition in chloromethane solvent via formation of a contact ion pair. The photochemical quantum yield and rate of photodecomposition depend on the electron affinity of solvent.

  4. Raman spectroscopy of organic dyes adsorbed on pulsed laser deposited silver thin films

    Energy Technology Data Exchange (ETDEWEB)

    Fazio, E.; Neri, F. [Dipartimento di Fisica della Materia e Ingegneria Elettronica, Universitá di Messina, V.le F. Stagno d’Alcontres 31, I-98166, Messina, Italy. (Italy); Valenti, A. [Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Universitá di Messina, V.le F. Stagno d’Alcontres 31, I-98166, Messina, Italy. (Italy); Ossi, P.M., E-mail: paolo.ossi@polimi.it [Dipartimento di Energia, Politecnico di Milano, via Ponzio 34-3, 20133 Milano, Italy. (Italy); Trusso, S.; Ponterio, R.C. [CNR-Istituto per i Processi Chimico-Fisici Sede di Messina, V.le F. Stagno d’Alcontres 37, I-98158 Messina, Italy. (Italy)

    2013-08-01

    The results of a surface-enhanced Raman scattering (SERS) study performed on representative organic and inorganic dyes adsorbed on silver nanostructured thin films are presented and discussed. Silver thin films were deposited on glass slides by focusing the beam from a KrF excimer laser (wavelength 248 nm, pulse duration 25 ns) on a silver target and performing the deposition in a controlled Ar atmosphere. Clear Raman spectra were acquired for dyes such as carmine lake, garanza lake and brazilwood overcoming their fluorescence and weak Raman scattering drawbacks. UV–visible absorption spectroscopy measurements were not able to discriminate among the different chromophores usually referred as carmine lake (carminic, kermesic and laccaic acid), as brazilwood (brazilin and brazilein) and as garanza lake (alizarin and purpurin). SERS measurements showed that the analyzed samples are composed of a mixture of different chromophores: brazilin and brazilein in brazilwood, kermesic and carminic acid in carmine lake, alizarin and purpurin in garanza lake. Detection at concentration level as low as 10{sup −7} M in aqueous solutions was achieved. Higher Raman intensities were observed using the excitation line of 632.8 nm wavelength with respect to the 785 nm, probably due to a pre-resonant effect with the molecular electronic transitions of the dyes.

  5. Sentinel Lymph Node Detection Using Laser-Assisted Indocyanine Green Dye Lymphangiography in Patients with Melanoma

    Directory of Open Access Journals (Sweden)

    Vikalp Jain

    2013-01-01

    Full Text Available Introduction. Sentinel lymph node (SLN biopsy is a vital component of staging and management of multiple cancers. The current gold standard utilizes technetium 99 (tech99 and a blue dye to detect regional nodes. While the success rate is typically over 90%, these two methods can be inconclusive or inconvenient for both patient and surgeon. We evaluated a new technique using laser-assisted ICG dye lymphangiography to identify SLN. Methods. In this retrospective analysis, we identified patients with melanoma who were candidates for SLN biopsy. In addition to tech99 and methylene blue, patients received a dermal injection of indocyanine green (ICG. The infrared signal was detected with the SPY machine (Novadaq, and nodes positive by any method were excised. Results. A total of 15 patients were evaluated, with 40 SLNs removed. Four patients were found to have nodal metastases on final pathology. 100% of these 4 nodes were identified by ICG, while only 75% (3/4 were positive for tech99 and/or methylene blue. Furthermore, none of the nodes missed by ICG (4/40 had malignant cells. Conclusion. ICG dye lymphangiography is a reasonable alternative for locating SLNs in patients with melanoma. Prospective studies are needed to better ascertain the full functionality of this technique.

  6. 5 LASER SPOT HEAT TRANSFER ACCOMPANIED BY PARABOLIC TEMPERATURE DISTRIBUTION INSIDE THE ROD

    Directory of Open Access Journals (Sweden)

    Doroshenko Ekaterina Sergeevna

    2013-01-01

    Full Text Available The co-authors have solved the problem of an unsteady temperature field inside a structural beam, if one of its ends is exposed to heating. The problem was solved using a traditional Fourier method. The solution derived by the co-authors was verified by the comparison of the final temperature field and the input data. MathCAD-14 software was employed to make calculations and to generate figures. Application of analytical methods, like Fourier series formalism, in combination with computing aids makes it possible to study both qualitative and quantitative constituents of the process of heat redistribution inside structural units in case of exposure to contingency actions. There will be no uniform temperature reduction in the course of intensive cooling of rod ends after the thermal exposure. If the value of the temperature conductivity coefficient is equal to .01, in 12 hours the residual heating may reach 20 % of the initial heating temperature.

  7. Triphenylamine based benzimidazole and benzothiazole: Synthesis and applications in fluorescent chemosensors and laser dyes

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yang [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Li, Bin, E-mail: libinteacher@163.com [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Zhang, Liming; Guan, Yunlong [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China)

    2014-01-15

    Triphenylamine based fluorescent dyes TPA-benzimidazole and TPA-benzothiazole have been designed and synthesized. The TPA-benzimidazole chemosensor was tested for a number of metal ions and found to exhibit binding affinity for Fe{sup 3+} and Hg{sup 2+} in acetonitrile, and the fluorescence quenching was achieved through a PET process. The appearance of an isosbestic point in absorption titrations and Job's plot analysis supported 1:1 stoichiometries for Fe{sup 3+} and Hg{sup 2+} ions. Laser experiments showed that under transversal pumping with a Q-switched Nd:YAG (355 nm) laser in toluene, TPA-benzothiazole exhibits efficient and stable amplified spontaneous emissions (ASE) at 436 nm. -- Highlights: • Triphenylamine based fluorescent dyes TPA-benzimidazole and TPA-benzothiazole have been designed and synthesized. • The TPA-benzimidazole exhibits binding affinity for Fe{sup 3+} and Hg{sup 2+} in acetonitrile and the fluorescence quenching was achieved through a PET process. • Under transversal pumping at 355 nm in toluene, TPA-benzothiazole exhibits efficient and stable amplified spontaneous emissions (ASE) in 436 nm.

  8. Rod-like microglia are restricted to eyes with laser-induced ocular hypertension but absent from the microglial changes in the contralateral untreated eye.

    Science.gov (United States)

    de Hoz, Rosa; Gallego, Beatriz I; Ramírez, Ana I; Rojas, Blanca; Salazar, Juan J; Valiente-Soriano, Francisco J; Avilés-Trigueros, Marcelino; Villegas-Perez, Maria P; Vidal-Sanz, Manuel; Triviño, Alberto; Ramírez, José M

    2013-01-01

    In the mouse model of unilateral laser-induced ocular hypertension (OHT) the microglia in both the treated and the normotensive untreated contralateral eye have morphological signs of activation and up-regulation of MHC-II expression in comparison with naïve. In the brain, rod-like microglia align to less-injured neurons in an effort to limit damage. We investigate whether: i) microglial activation is secondary to laser injury or to a higher IOP and; ii) the presence of rod-like microglia is related to OHT. Three groups of mice were used: age-matched control (naïve, n=15); and two lasered: limbal (OHT, n=15); and non-draining portion of the sclera (scleral, n=3). In the lasered animals, treated eyes as well as contralateral eyes were analysed. Retinal whole-mounts were immunostained with antibodies against, Iba-1, NF-200, MHC-II, CD86, CD68 and Ym1. In the scleral group (normal ocular pressure) no microglial signs of activation were found. Similarly to naïve eyes, OHT-eyes and their contralateral eyes had ramified microglia in the nerve-fibre layer related to the blood vessel. However, only eyes with OHT had rod-like microglia that aligned end-to-end, coupling to form trains of multiple cells running parallel to axons in the retinal surface. Rod-like microglia were CD68+ and were related to retinal ganglion cells (RGCs) showing signs of degeneration (NF-200+RGCs). Although MHC-II expression was up-regulated in the microglia of the NFL both in OHT-eyes and their contralateral eyes, no expression of CD86 and Ym1 was detected in ramified or in rod-like microglia. After 15 days of unilateral lasering of the limbal and the non-draining portion of the sclera, activated microglia was restricted to OHT-eyes and their contralateral eyes. However, rod-like microglia were restricted to eyes with OHT and degenerated NF-200+RGCs and were absent from their contralateral eyes. Thus, rod-like microglia seem be related to the neurodegeneration associated with HTO.

  9. Rod-like microglia are restricted to eyes with laser-induced ocular hypertension but absent from the microglial changes in the contralateral untreated eye.

    Directory of Open Access Journals (Sweden)

    Rosa de Hoz

    Full Text Available In the mouse model of unilateral laser-induced ocular hypertension (OHT the microglia in both the treated and the normotensive untreated contralateral eye have morphological signs of activation and up-regulation of MHC-II expression in comparison with naïve. In the brain, rod-like microglia align to less-injured neurons in an effort to limit damage. We investigate whether: i microglial activation is secondary to laser injury or to a higher IOP and; ii the presence of rod-like microglia is related to OHT. Three groups of mice were used: age-matched control (naïve, n=15; and two lasered: limbal (OHT, n=15; and non-draining portion of the sclera (scleral, n=3. In the lasered animals, treated eyes as well as contralateral eyes were analysed. Retinal whole-mounts were immunostained with antibodies against, Iba-1, NF-200, MHC-II, CD86, CD68 and Ym1. In the scleral group (normal ocular pressure no microglial signs of activation were found. Similarly to naïve eyes, OHT-eyes and their contralateral eyes had ramified microglia in the nerve-fibre layer related to the blood vessel. However, only eyes with OHT had rod-like microglia that aligned end-to-end, coupling to form trains of multiple cells running parallel to axons in the retinal surface. Rod-like microglia were CD68+ and were related to retinal ganglion cells (RGCs showing signs of degeneration (NF-200+RGCs. Although MHC-II expression was up-regulated in the microglia of the NFL both in OHT-eyes and their contralateral eyes, no expression of CD86 and Ym1 was detected in ramified or in rod-like microglia. After 15 days of unilateral lasering of the limbal and the non-draining portion of the sclera, activated microglia was restricted to OHT-eyes and their contralateral eyes. However, rod-like microglia were restricted to eyes with OHT and degenerated NF-200+RGCs and were absent from their contralateral eyes. Thus, rod-like microglia seem be related to the neurodegeneration associated with HTO.

  10. Enhancing the Performance of Distributed Feedback Dye Lasers and Plasmonic V-grooves for Lab-on-a-chip Systems

    DEFF Research Database (Denmark)

    Smith, Cameron

    of the laser emission wavelength. We provide a framework for designing optimized DFB laser sensors comprising a thin TiO2 guiding layer. Regarding the second, plasmonic V-grooves offer a means to control the trade-off between e-field confinement and propagation length by varying the V-shape profile, opening......The ability to perform laboratory operations in compact systems is not only advantageous for the development of diagnostics tools and their production, but also provides unique opportunities to explore the natural world on the micro- and nanoscale. To this end, we focus on two optical schemes: 1......) polymer-based distributed feedback (DFB) dye lasers, and 2) plasmonic V-grooves. Regarding the first, DFB dye lasers are well suited to serve as compact, minimal analyte volume and highly sensitive refractive index sensors, where changes occurring in an analyte result in readily measurable shifts...

  11. Generation of intense 10-ps, 193-nm pulses using simple distributed feedback dye lasers and an ArF(*) amplifier.

    Science.gov (United States)

    Hatten, D L; Cui, Y; Iii, W T; Mikes, T; Goldhar, J

    1992-11-20

    A pair of holographic distributed feedback dye lasers is used to generate 10-ps pulses at two selected wavelengths that are mixed in a BBO crystal to produce a pulse ~ 10 ps in duration at 193 nm. This seed pulse is subsequently amplified in an ArF(*) excimer laser to an energy of 10-15 mJ with <40 microJ in amplified spontaneous emission. The pulses are nearly transform limited and diffraction limited.

  12. Microfabrication of Tungsten, Molybdenum and Tungsten Carbide Rods by Laser-Assisted CVD

    OpenAIRE

    Björklund, Kajsa

    2001-01-01

    Thin films of refractory metals and carbides have been studied extensively over many years because of their wide range of application. The two major techniques used are Chemical Vapour Deposition (CVD) and Physical Vapour Deposition (PVD). These can result in the deposition of two-dimensional blanket or patterned thin films. Laser-assisted Chemical Vapour Deposition (LCVD) can provide a maskless alternative for localised deposition in two and three dimensions. This thesis describes LCVD of mi...

  13. The influence of phase transformation hardening on continuous laser processing of notches for fracture splitting of a C70S6 connecting rod

    Science.gov (United States)

    Kou, S. Q.; Gao, Y.; Shi, Z.

    2017-01-01

    The dynamic process of local material microstructure and hardness of continuous laser grooving for fracture splitting of a C70S6 connecting rod was studied. According to the phase transformation characteristics of C70S6 steel during laser processing, the coupling calculation between the transient temperature field and phase transformation process of continuous laser grooving was carried out, and then the phase transformation process and phase compositions in the heat affected zone (HAZ) was obtained. The research results showed that the HAZ was composed of martensite and pearlite as well as residual austenite after continuous laser grooving, and the generation of the martensite in the HAZ is beneficial to the subsequent splitting process; meanwhile, the hardening effect of continuous laser grooving is remarkable on the HAZ, and the requirement for the cutting tool and technique used at the subsequent machining process for the fine boring of the big end hole should be higher.

  14. Detection of early interproximal caries in vitro using laser fluorescence, dye-enhanced laser fluorescence and direct visual examination.

    Science.gov (United States)

    Eggertsson, H; Analoui, M; van der Veen, M; González-Cabezas, C; Eckert, G; Stookey, G

    1999-01-01

    This in vitro study evaluated the use of laser fluorescence (LF) for the detection of early interproximal carious lesions and whether the detection could be enhanced using a fluorescent dye (DELF). Direct visual examination (DV) was used for comparison. Eighty extracted teeth were used, arranged in 20 blocks, each block having 2 premolars and 2 molars, lined up in a simulated sextant situation. After cleaning with a microabrasion kit, a subcontact window on half of the surfaces (60) was exposed to Carbopol white-spot solution for 5 days. The teeth were remounted in stone and examined by three independent examiners. For LF and DELF an argon laser was used (mixed wavelength of 488 and 514 nm) viewed through glasses (excluding wavelength DELF a sodium fluorescein dye (0. 075%) was applied before examination. A clinical examination light was used for DV. The approximal surfaces were scored for lesion presence or absence. To verify lesion presence, the subcontact area was cut perpendicularly to the surface, stained with rhodamine B, and images were taken using a confocal microscope. The images were analyzed using a histogram program for lesion depth and image area. Lesions were present in 62 out of 120 approximal surfaces, with an average depth of 60 microm (range 17-190 microm). Sensitivity ranges for LF, DELF and DV were 56-74, 61-79 and 58-74%, and specificity ranges 67-78, 86-98 and 83-97%, respectively. With this model DELF compared favorably with DV and LF in sensitivity, but specificity was better for DELF and DV than for LF.

  15. Compound Cellular Imaging of Laser Scanning Confocal Microscopy by Using Gold Nanoparticles and Dyes

    Directory of Open Access Journals (Sweden)

    Jiunn-Woei Liaw

    2008-04-01

    Full Text Available Combining the scattered light of gold nanoparticles (GNPs and the fluorescence of dye molecules, a compound cellular imaging of laser scanning confocal microscopy (LSCM is obtained. The human breast cancer cell line (MDA-MB-435S, BCRC 60429 is used for experiment. These cells are incubated with a glucose medium containing GNPs for 26 hours, and then are stained by Prodium Iodide (PI for their nuclei. By using a single laser to illuminate these cells and adjusting the ranges of two bandpass filters for the detection, the scattered light from the GNPs and the fluorescence of PI can be induced simultaneously, but be detected separately without crosstalk. Furthermore, a compound cellular image can be obtained by merging the two images of the expressions of GNP and PI together. From the TEM images of these cells, it is observed that GNPs are aggregated in the vesicles of the cytoplasm due to the cell’s endocytosis. The aggregation of GNPs makes the surface plasmon resonance band of GNPs broadened, so that strong scattered light from GNPs can be generated by the illumination of different-wavelength lasers (458, 488, 514, 561, and 633 nm.

  16. Dye-enhanced laser fluorescence detection of caries lesions around brackets.

    Science.gov (United States)

    Alencar, Cássio José Fornazari; Braga, Mariana Minatel; de Oliveira, Elisabeth; Nicolau, José; Mendes, Fausto Medeiros

    2009-11-01

    The aim was to evaluate the performance of DIAGNOdent [laser fluorescence(LF) and LFpen] devices enhanced by fluorescent dye in detecting mineral loss around brackets and comparing the inhibitory effect of bonding material on artificial demineralization, and to verify whether LF methods show the same trends of mineral loss. Brackets were bonded to premolar halves with Fuji Ortho LC, Transbond XT, and Ortho Glass LC cements (n = 15). The teeth were soaked in demineralizing solution (pH = 4.8) for 16 days. Mineral loss was calculated by atomic emission spectrometry, and lesions were measured with LF devices with dye [tetrakis N-methylpyridyl porphyrin (TMPyP)]. Groups were compared with regard to LF readings and mineral loss, and performance of caries detection was calculated. Higher mineral loss and LF-TMPyP values occurred in the resin group. LFpen-TMPyP readings were significantly higher in the demineralized groups. Correlation was observed between mineral loss and LF measurements. LF methods are capable of identifying lower demineralization around brackets bonded with resin-modified glass ionomer cements.

  17. Photoactive Nanomaterials Inspired by Nature: LTL Zeolite Doped with Laser Dyes as Artificial Light Harvesting Systems

    Directory of Open Access Journals (Sweden)

    Leire Gartzia-Rivero

    2017-05-01

    Full Text Available The herein reported work describes the development of hierarchically-organized fluorescent nanomaterials inspired by plant antenna systems. These hybrid materials are based on nanostructured zeolitic materials (LTL zeolite doped with laser dyes, which implies a synergism between organic and inorganic moieties. The non-interconnected channeled structure and pore dimensions (7.1 Å of the inorganic host are ideal to order and align the allocated fluorophores inside, inferring also high thermal and chemical stability. These artificial antennae harvest a broad range of chromatic radiation and convert it into predominant red-edge or alternatively white-light emission, just choosing the right dye combination and concentration ratio to modulate the efficiency of the ongoing energy transfer hops. A further degree of organization can be achieved by functionalizing the channel entrances of LTL zeolite with specific tailor-made (stopcock molecules via a covalent linkage. These molecules plug the channels to avoid the leakage of the guest molecules absorbed inside, as well as connect the inner space of the zeolite with the outside thanks to energy transfer processes, making the coupling of the material with external devices easier.

  18. Pulsed dye laser versus Nd:YAG laser in the treatment of plantar warts: a comparative study.

    Science.gov (United States)

    El-Mohamady, Abd El-Shakor; Mearag, Ibrahim; El-Khalawany, Mohamed; Elshahed, Ahmed; Shokeir, Hisham; Mahmoud, Anas

    2014-05-01

    Plantar warts are common viral infection that are usually challenging in treatment. Conventional treatment methods are usually invasive, have low efficacy, and need long recovery periods. In this study, we compared pulsed dye laser (PDL) and neodymium yttrium aluminum garnet (Nd:YAG) lasers in the treatment of recalcitrant plantar warts. The study included 46 patients with multiple plantar warts. In each patient, lesions were divided into two groups: one treated with Nd:YAG (spot size, 7 mm; energy, 100 J/cm(2); and pulse duration, 20 ms) and the other with PDL (spot size, 7 mm; energy, 8 J/cm(2); and pulse duration, 0.5 ms). Laser sessions were applied every 2 weeks with maximum of six sessions. The study included 63% males and 37% females with a mean age of 29.6 ± 7.34 years. The cure rate was 73.9% with PDL with no significant difference (p = 0.87) from Nd:YAG (78.3%). The number of sessions required was more in PDL (mean, 5.05 ± 0.2) compared with Nd:YAG (mean, 4.65 ± 0.5) but without significant difference. Complications were significantly higher with Nd:YAG (43.5%) compared with PDL (8.7%). Hematoma was the most common complication recorded by Nd:YAG (28.3 %), and it was significantly higher (p = 0.002) than PDL (2.2%). Relapse was recorded in 8.7% with Nd:YAG compared with 13% in PDL with no significant difference (p = 0.74). Our results suggested that PDL and Nd:YAG lasers are effective in the treatment of resistant plantar warts. PDL is safer and less painful but needs more sessions, while Nd:YAG is more painful and shows more complications.

  19. Laser Ultrasonic System for Surface Crack Visualization in Dissimilar Welds of Control Rod Drive Mechanism Assembly of Nuclear Power Plant

    Directory of Open Access Journals (Sweden)

    Yun-Shil Choi

    2014-01-01

    Full Text Available In this paper, we propose a J-groove dissimilar weld crack visualization system based on ultrasonic propagation imaging (UPI technology. A full-scale control rod drive mechanism (CRDM assembly specimen was fabricated to verify the proposed system. An ultrasonic sensor was contacted at one point of the inner surface of the reactor vessel head part of the CRDM assembly. Q-switched laser beams were scanned to generate ultrasonic waves around the weld bead. The localization and sizing of the crack were possible by ultrasonic wave propagation imaging. Furthermore, ultrasonic spectral imaging unveiled frequency components of damage-induced waves, while wavelet-transformed ultrasonic propagation imaging enhanced damage visibility by generating a wave propagation video focused on the frequency component of the damage-induced waves. Dual-directional anomalous wave propagation imaging with adjacent wave subtraction was also developed to enhance the crack visibility regardless of crack orientation and wave propagation direction. In conclusion, the full-scale specimen test demonstrated that the multiple damage visualization tools are very effective in the visualization of J-groove dissimilar weld cracks.

  20. Spectroscopic studies of biologically active coumarin laser dye: Evaluation of dipole moments by solvatochromic shift method

    Science.gov (United States)

    Koppal, V. V.; Muddapur, G. V.; Patil, N. R.; Melavanki, R. M.

    2016-05-01

    In this paper we attempted to record absorption and emission spectra of 2-acetyl-3H-benzo[f]chromen-3-one [2AHBC] laser dye in different solvents of varying polarities to investigate its solvatochromic behavior. The two electronic states dipole moments of 2AHBC are calculated using solvatochromic spectral shifts which are correlated with dielectric constant (ɛ) refractive index (n) of various solvents. A systematic approach is made to estimate ground and excited state dipole moments on the basis of different solvent correlation methods like Bilot-Kawski equations, Lippert-Mataga, Bakhsheiv, Kawaski-Chamma-Viallet and Reichardt methods. Dipole moments in the excited state was found to be higher than the ground state by confirming π→π* transition.

  1. The effect on the ultrastructure of dental enamel of excimer-dye, argon-ion and CO2 lasers.

    Science.gov (United States)

    Palamara, J; Phakey, P P; Orams, H J; Rachinger, W A

    1992-12-01

    This study aimed to investigate the ultrastructural changes that occur in dental enamel irradiated with pulsed excimer-dye, continuous-wave (CW) argon-ion and CW CO2 lasers. The pulsed excimer-dye laser produced deep craters, rough damaged surfaces with underlying porosity and amorphous vitrified material. The vitrification of the enamel indicated that the temperature in these areas must have been at least in the range 1280 to 1600 degrees C. The CW argon-ion laser irradiation produced a changed non-cratered surface with inter-crystalline porosity and a mixture of small and some large irregularly packed recrystallized enamel crystals. The CW CO2 laser produced shallow craters, surface crazing and lifting off the removal of the surface layer to expose the underlying roughened enamel. The ultrastructure revealed inter- and intra-crystalline porosity, a mixture of small but variable size irregularly packed recrystallized enamel crystals and also well packed large crystals which indicated further grain growth. The porosity in lased enamel was overall very similar to that seen in enamel heated in an electric furnace to a temperature of 600 degrees C. The presence of recrystallized enamel crystals indicated a temperature rise of approximately 1000 degrees C and the grain growth indicated that a temperature > or = 1000 degrees C existed for some time after the laser irradiation. In general the excimer-dye laser produced most surface destruction because of its higher power density and shorter interaction time and the argon-ion laser produced least damage. These results indicated that the lasers used in this study require much more refinement before they can find therapeutic application to dental enamel, and this may well be the case for other lasers being investigated for clinical dental practise.

  2. Time domain measuring system of molecular fluorescence with real-time monitor and control of pulsed dye laser

    Science.gov (United States)

    Taira, Y.; Suzuki, T.; Kato, H.; Konishi, N.; Kasuya, T.

    1982-04-01

    A computer controlled system is presented for a high-precision, time-domain measurement of molecular fluorescence induced by a pulsed dye laser field. In this system three intelligent functions are assembled by the system controller: they are an automatic wavelength control of pulsed dye laser to 0.45 GHz resolution, a digital wavelength meter of 10-7 precision, and a high-speed waveform digitizer with 10 ps inherent resolution. Then the system achieves a unique capability such as to record real-time data of fluorescence decay in the nanosecond regime under an on-line monitor and control of the laser wavelength to milliangstrom precision. The basic constitution and practical performance of the system are described with particular emphasis on its high precision and multi-task capability.

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

    Institute of Scientific and Technical Information of China (English)

    吕国; 滕浩; 王立娜; 王睿; 王军利; 魏志义

    2015-01-01

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

  4. Superradiant properties of 4,4'-bis(1¤H¤-phenanthro[9,10-¤d¤]imidazol-2-yl)biphenyl and how a laser dye with exceptional stability can be obtained in only one synthetic step

    DEFF Research Database (Denmark)

    Krebs, Frederik C; Lindvold, Lars René; Jørgensen, M.

    2001-01-01

    The extremely facile synthesis of a very stable laser dye with superradiant properties is reported. The laser action of the dye is demonstrated through a transverse pumping scheme with the advantage that no elaborate laser resonator is required due to the very high gain of the laser medium. The e...

  5. Laser-induced removal of a dye C.I. Acid Red 87 using n-type WO3 semiconductor catalyst.

    Science.gov (United States)

    Qamar, M; Gondal, M A; Hayat, K; Yamani, Z H; Al-Hooshani, K

    2009-10-30

    Water contamination by organic substances such as dyes is of great concern worldwide due to their utilization in many industrial processes and environmental concerns. To cater the needs for waste water treatment polluted with organic dyes, laser-induced photocatalytic process was investigated for removal of a dye derivative namely Acid Red 87 using n-type WO3 semiconductor catalyst. The degradation was investigated in aqueous suspensions of tungsten oxide under different experimental conditions using laser instead of conventional UV lamp as an irradiation source. The degradation process was monitored by measuring the change in dye concentration as a function of laser irradiation time by employing UV spectroscopic analysis. The degradation of dye was studied by varying different parameters such as laser energy, reaction pH, substrate concentration, catalyst concentration, and in the presence of electron acceptors such as hydrogen peroxide (H2O2), and potassium bromate (KBrO3). The degradation rates were found to be strongly dependent on all the above-mentioned parameters. Our experimental results revealed that the dye degradation process was very fast (within few minutes) under laser irradiation as compared to conventional setups using broad spectral lamps (hours or days) and this laser-induced photocatalytic degradation method could be an effective means to eliminate the pollutants present in liquid phase. The experience gained through this study could be beneficial for treatment of waste water contaminated with organic dyes and other organic pollutants.

  6. A comparison of crud phases appearing on some Swedish BWR fuel rods using Laser Raman Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hermansson, H.P. [Studsvik Nuclear AB, Nykoeping (Sweden)]|[Lulea Univ. of Technology (Sweden)

    2002-07-01

    Previous investigations showed that laser Raman spectroscopy (LRS) can be used as a phase specific analytical tool for radioactive fuel crud samples and also for details in the underlying layer of zirconium dioxide. It is relatively easy to record Raman spectra that discriminate between chemical phases for all crud oxides of interest. The method has therefore been recommended for crud investigations within the Swedish program. At ideal conditions the resolution is about 1 {mu}m, permitting detailed position determination of crud phases in the sample. Therefore LRS is a very good complement to X-ray diffraction (XRD). The methods for sample preparation and handling of radioactive crud samples for LRS turn out to be relatively simple. A detailed LRS study on fuel crud samples from Barsebaeck 2, Forsmark 2, Forsmark 3 and Ringhals 1 was performed in this work. All of those Swedish BWRs were operated at different conditions at the time of sampling. The chemistry regimes covered NWC, HWC and other variable conditions. Also different types of fuel, exposure times and sampling positions were selected. (authors)

  7. Solar Lentigines: Evaluating Pulsed Dye Laser (PDL) as an Effective Treatment Option

    Science.gov (United States)

    Ghaninejhadi, Hayedeh; Ehsani, Amirhooshang; Edrisi, Ladan; Gholamali, Fatemeh; Akbari, Zahra; Noormohammadpour, Pedram

    2013-01-01

    Introduction: Solar lentigines are among commonest cosmetic problems. There are many topical therapies suggested to treat these lesions including cryotherapy, chemical peeling with tri chloro acetic acid (TCA) and laser therapy with q-switched lasers as well as long pulsed lasers. Considering possible treatment side effects (PIH, scar) with cryotherapy and peeling in Iranian patients (darker skin types) it seems necessary to try to find alternative measures. The aim of the present study was to evaluate effect of long pulsed dye laser (LPDL) on lentigines via an objective method (computerized dermoscopy). Methods: Patients with pathologically confirmed lentigines were selected if they agreed to participate in the study,were not treated before, hadn’t history of psoriasis, vitiligo, scar formation and were not pregnant. Letigines were dermoscopied before and after treatment with PDL (V-beam, 595nm, Candela Corp. Wayland, USA) using fluence of 10 joules,without DCD (dynamic cooling device) via extra compress lens provided with laser system.The resulting figures were compared by two academic unrelated dermatologists as well as by computerized analysis. Post laser side effects were treated with topical antibiotics and mild topical steroids. Patients were followed for six months after the end of the study to determine the rate of recurrence via dermoscopy of sites of previous lesions and also delayed side effects. Results: A total of 21 patients with the same number of lesions, were included in the study.Mean age of patients was 54.2 years (±23.3) ranging from 39 to 71 years. Included patient swere 18 females and three males. From 21 treated lesions, 11 were located on the hands and 10 on the face. Comparing before and after photographs taken through dermoscopy system,revealed that approximately 57% of patients had more than 75% improvement. Mean pigment analysis score (calculated by computerized dermoscope software) was respectively 8 and 2 before and after PDL

  8. Treatment of port-wine stains with flash lamp pumped pulsed dye laser on Indian skin: A six year study

    Directory of Open Access Journals (Sweden)

    Chandroth Ponnambath Thajudheen

    2014-01-01

    Full Text Available Context: Port-wine stain (PWS is one of the commonly encountered congenital cutaneous vascular lesions, with an equal sex distribution. Pulsed dye lasers (PDL have revolutionized the treatment of both congential and acquired cutaneous vascular lesions. The pulsed dye lasers owing to its superior efficacy and safety profile have become the gold standard for the management of port-wine stains. Aims: To evaluate the efficacy and side effects of pulsed dye laser for the management of Port-wine stain on Indian skin. Materials and Methods: Seventy five patients of Fitzpatrick skin types IV&V with PWS underwent multiple treatments with PDL (V beam-Candela over a period of six years at monthly intervals. Laser parameters were wavelength 595nm, spot sizes 7-10mm, fluence 6-12 j/cm2, pulse duration 0.45-10ms, along with cryogen cooling. Serial photographs were taken before and after every session. Clinical improvement scores of comparable photographs using a quartile grading (o=80% were judged independently by two dermatologists after the series of treatment. Minimum number of treatments was 6 and maximum 17.They were followed up at six monthly intervals to observe re darkening of PWS. Results: No patient showed total clearance.Grade3 improvement was observed in 70 % of children and 50% of adults after 8-10 sessions. Children showed better and faster response than adults. Thirty percent of patients developed post inflammatory hyper pigmentation which resolved over a period of six to eight weeks. Two patients had superficial scarring due to stacking of pulses. None of the patients showed re darkening of PWS till now. Conclusion: Pulsed dye laser is an effective and safe treatment for port-wine stain in Indian skin.

  9. Single longitudinal mode oscillations in the converging-straight-diverging dye cell pumped by a 9 kHz copper vapor laser

    Science.gov (United States)

    Rawat, V. S.; Kawade, Nitin; Manohar, K. G.

    2017-01-01

    To minimize the thermal and flow induced effect on the single mode dye laser at higher pulse repetition rate several dye cell flow geometries have been studied using computational fluid dynamics (CFD) model. The evolution of velocity profiles along the straight section of a converging - straight - diverging dye cell has been studied and the boundary layer thickness at different locations in the straight section of the flow channel has been captured using the CFD model. It has been observed that the boundary layer thickness reduces with increasing flow velocity in the dye cell. The boundary layer thickness is minimum at the throat of the dye cell i.e., from where the straight section commence and the velocity profile is almost flat. This dye cell provides nearly two times lesser pressure drop for higher flow velocities in comparison to the straight rectangular dye cell. These dye cells have been used for generating single mode oscillation in the short cavity grazing incidence grating (GIG) cavity. We had experimentally observed that the wavelength fluctuations around the mean value is nearly 7 times less for the converging-straight-diverging dye cell at a relatively higher flow velocities of nearly 12 m/s. For rectangular straight dye cell it is very difficult to obtain a single mode laser at this higher flow velocity.

  10. Solution-processable, photo-stable, low-threshold, and broadly tunable thin film organic lasers based on novel high-performing laser dyes

    Science.gov (United States)

    Díaz-García, María. A.; Morales-Vidal, Marta; Ramírez, Manuel G.; Villalvilla, José M.; Boj, Pedro G.; Quintana, José A.; Retolaza, A.; Merino, S.

    2015-09-01

    Thin film organic lasers (TFOLs) represent a new generation of inexpensive, mechanically flexible devices with demonstrated applicability in numerous applications in the fields of spectroscopy, optical communications and sensing requiring an organic, efficient, stable, wavelength-tunable and solution-processable laser material. A distributed feedback (DFB) laser is a particularly attractive TFOL because it shows single mode emission, low pump energy, easy integration with other devices, mechanical flexibility and potentially low production cost. Here, amplified spontaneous emission (ASE) and DFB laser applications of novel high performing perylene dyes and p-phenylenevinylene (PV) oligomers, both dispersed in thermoplastic polymers, used as passive matrixes, are reported. Second-order DFB lasers based on these materials show single mode emission, wavelength tunability across the visible spectrum, operational lifetimes of >105 pump pulses, larger than previously reported PV oligomers or polymers, and thresholds close to pumping requirements with light-emitting diodes.

  11. Fractional Carbon Dioxide, Long Pulse Nd:YAG and Pulsed Dye Laser in the Management of Keloids.

    Science.gov (United States)

    Annabathula, Ashwini; Sekar, C Shanmuga; Srinivas, C R

    2017-01-01

    Keloids are abnormal wound responses characterised by excessive deposition of collagen and glycoprotein. They are both aesthetically and symptomatically distressing for most of the patients. There are reports of keloid management with pulsed dye laser (PDL), fractional carbon dioxide (CO2) laser and neodymium-doped yttrium aluminium garnet (Nd:YAG) laser individually and also in combination of CO2 with PDL and CO2 with Nd:YAG. Here, we discuss a combination of all the 3 lasers as a therapy for keloids. This study aims to assess the efficacy of fractional CO2 laser, long pulse Nd:YAG laser and PDL in the management of keloids. Fifteen patients with keloids were treated by fractional CO2 laser, followed by PDL and long pulse Nd:YAG laser at monthly intervals. Four patients discontinued the study and were lost for follow-up. Photographs were taken at the beginning of the treatment and at the end of five sessions. Clinical improvement was analysed based on a visual analogue scale graded by three blinded observers after assessing the clinical photographs for the improvement in size, colour and aesthetic impression. Of the 11 patients, one patient had excellent improvement, one patient had good improvement, four patients had moderate improvement, two patients had mild improvement and three had no improvement. Lasers may have a synergistic effect when combined with other modalities of treatment but cannot be used as monotherapy in the treatment of keloids.

  12. Study of nonlinear refraction of organic dye by Z-scan technique using He-Ne laser

    Science.gov (United States)

    Medhekar, S.; Kumar, R.; Mukherjee, S.; Choubey, R. K.

    2013-02-01

    Laser induced third-order nonlinear optical responses of Brilliant Green solution has been investigated by utilizing single beam Z-scan technique with a continuous-wave He-Ne laser radiation at 632.8 nm. It was observed that the material exhibits self-defocusing type optical nonlinearity. The measurements of nonlinear refraction were carried out at different dye concentrations and found that the increase in solution concentration leads to the linear increase of the nonlinear refractive index. The experimental results confirm great potential of the Brilliant Green for the application in nonlinear optical devices.

  13. Study of nonlinear refraction of organic dye by Z-scan technique using He-Ne laser

    Energy Technology Data Exchange (ETDEWEB)

    Medhekar, S.; Kumar, R.; Mukherjee, S.; Choubey, R. K. [Dept. of Applied Physics, Birla Institute of Technology, Mesra, Ranchi - 835215, Jharkhand (India)

    2013-02-05

    Laser induced third-order nonlinear optical responses of Brilliant Green solution has been investigated by utilizing single beam Z-scan technique with a continuous-wave He-Ne laser radiation at 632.8 nm. It was observed that the material exhibits self-defocusing type optical nonlinearity. The measurements of nonlinear refraction were carried out at different dye concentrations and found that the increase in solution concentration leads to the linear increase of the nonlinear refractive index. The experimental results confirm great potential of the Brilliant Green for the application in nonlinear optical devices.

  14. Photodegradation and self-healing in a Rhodamine 6G dye and Y$_2$O$_3$ nanoparticle-doped polyurethane random laser

    CERN Document Server

    Anderson, Benjamin R; Eilers, Hergen

    2015-01-01

    One of the fundamental difficulties in implementing organic dyes in random lasers is irreversible photodegradation of the dye molecules, leading to loss of performance and the need to replace the dye. We report the observation of self-healing after photodegradation in a Rhodamine 6G dye and nanoparticle doped polyurethane random laser. During irradiation we observe two distinct temporal regions in which the random lasing (RL) emission first increases in intensity and redshifts, followed by further redshifting, spectral broadening, and decay in the emission intensity. After irradiation the emission intensity is found to recover back to its peak value, while still being broadened and redshifted, which leads to the result of an enhancement of the spectrally integrated intensity. We also perform IR-VIS absorbance measurements and find that the results suggest that during irradiation some of the dye molecules form dimers and trimers and that the polymer host is irreversibly damaged by photooxidation and Norrish ty...

  15. Shape induced (spherical, sheets and rods) optical and magnetic properties of CdS nanostructures with enhanced photocatalytic activity for photodegradation of methylene blue dye under ultra-violet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Bilal; Kumar, Sachin; Kumar, Sumeet; Ojha, Animesh K., E-mail: animesh@mnnit.ac.in

    2016-09-15

    CdS nanostructures of different shapes such as, nanoparticles (NPs), nanosheets (NS) and nanorods (NRs) have been synthesized by one step chemical solvothermal method. The synthesized samples were characterized by X-ray diffractometer (XRD), transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy, UV–visible (UV-VIS) spectroscopy, Raman spectroscopy (RS) and vibrating sample magnetometer (VSM) techniques. The effect of shape on optical and magnetic properties of CdS nanostructures was studied. The optical band gap and emission spectra are found to be shape dependent. CdS NRs were found to have high saturation (Ms) magnetization than that of CdS NPs and NS. The role of shape on photocatalytic performance of CdS NPs, NS and NRs was investigated by monitoring the photodegradation of methylene blue (MB) dye under the UV irradiation of wavelength 365 nm. The lower recombination rate of electron-hole pairs and larger surface area as reactive facets for adsorption of MB dye molecules in CdS NS are mainly lead to the better photocatalytic performance of CdS NS compared to NPs and NRs. - Highlights: • Synthesis of CdS nanostructures with different shapes (spherical, rod and sheet) by easy and low cost solvothermal method. • Shape induced optical and magnetic properties of CdS nanostructures have been investigated. • The shapes of nanostructures play an important role for photocatalytic performance of CdS nanostructures.

  16. Phase behavior of colloidal silica rods

    NARCIS (Netherlands)

    Kuijk, A.; Byelov, D.; Petukhov, A.V.; van Blaaderen, A.; Imhof, A.

    2012-01-01

    Recently, a novel colloidal hard-rod-like model system was developed which consists of silica rods [Kuijk et al., JACS, 2011, 133, 2346]. Here, we present a study of the phase behavior of these rods, for aspect ratios ranging from 3.7 to 8.0. By combining real-space confocal laser scanning microscop

  17. Evaluation of laser desorption mass spectrometry and UV accelerated aging of dyes on paper as tools for the evaluation of a questioned document.

    Science.gov (United States)

    Grim, Donzna M; Siegel, Jay; Allison, John

    2002-11-01

    Laser desorption mass spectrometry (LDMS) may be used for the detection and identification of dyes found in inks. Naturally-aged and artificially-aged blue and black ballpoint pen inks containing the cationic dye methyl violet were analyzed on paper. The average molecular weight of the dye sample was calculated from LD mass spectral data and plotted versus time. The resulting aging curves demonstrate that, as dye degradation increases, the average molecular weight of the dye decreases. Typical variables involved in ink aging, such as the type of paper and ink formulation, were investigated. Results show that these variables influence the rate of dye degradation. Furthermore, UV accelerated aging has been developed and tested as an alternative to thermal approaches.

  18. Adsorption of Cationic Laser Dye onto Polymer/Surfactant Complex Film

    Institute of Scientific and Technical Information of China (English)

    Pabitra Kumar Paul; Syed Arshad Hussain; Debajyoti Bhattacharjee; Mrinal Pal

    2011-01-01

    Fabrication of complex molecular films of organic materials is one of the most important issues in modern nanoscience and nanotechnology. Soft materials with flexible properties have been given much attention and can be obtained through bottom up processing from functional molecules, where self-assembly based on supramolecular chemistry and designed assembly have become crucial processes and technologies. In this work, we report the successful incorporation of cationic laser dye rhodamine 6G abbreviated as R6G into the pre-assembled polyelectrolyte/surfactant complex film onto quartz substrate by electrostatic adsorption technique. Poly(allylamine hydrochloride) (PAH) was used as polycation and sodium dodecyl sulphate (SDS) was used as anionic surfactant. UV-Vis absorption spectroscopic characterization reveals the formation of only H-type aggregates of R6G in their aqueous solution and both H- and J-type aggregates in PAH/SDS/R6G complex layer-by-layber films as well as the adsorption kinetics of R6G onto the complex films. The ratio of the absorbance intensity of two aggregated bands in PAH/SDS/R6G complex films is merely independent of the concentration range of the SDS solution used to fabricate PAH/SDS complex self-assembled films. Atomic force microscopy reveals the formation of R6G aggregates in PAH/SDS/R6G complex films.

  19. Treatment of Basal Cell Carcinomas with Pulsed Dye Laser: A Case Series

    Directory of Open Access Journals (Sweden)

    Norman Minars

    2012-01-01

    Full Text Available Background. Basal cell carcinoma (BCC is the most prevalent skin cancer. Because of its highly vascular characteristic, it is amendable to treatment with pulse dye laser (PDL. The goal of this study is to determine the safety and efficacy of PDL therapy for mostly facial BCCs. Materials and Methods. Sixteen men and thirteen women (29 total with 39 biopsy-proven BCCs were treated with 1–4 PDL (595 nm therapies at 2–4-week intervals. The treatment parameters included pulse energy of 15 J/cm 2, pulse length of 3 millisecond, with no dynamic cooling, and 7 mm spot size. The age of the patients was 30–90 years (mean 73 years. Response rates were evaluated by the clinical assessments with mean followup of 11 months. Results. Twenty-four patients with thirty-two tumors reached at least three months followup: 24/32 (75% tumors with complete resolution (mean 3 treatment sessions; 5/32 (16% tumors recurred; 3/32 (9% tumors with incomplete responses after four treatments. Minimal side effects and discomfort were experienced by the patients with PDL therapy. Conclusion. PDL is a safe, tolerable, and moderately effective method of treating various BCCs. The ideal niche and standardized settings for PDL treatment of BCCs are yet to be determined.

  20. Initial clinical experience with a new pulsed dye laser device in angioplasty of limb ischemia and shunt fistula obstructions

    Energy Technology Data Exchange (ETDEWEB)

    Zwaan, M.; Weiss, H.D.; Kagel, H.; Gmelin, E.; Rinast, E. (Medical University of Luebeck (Germany). Department of Radiology); Goethlin, J.H. (Sahlgrenska Sjukhuset, Goeteborg (Sweden)); Kummer, D. (Medical University of Luebeck (Germany). Department of Angiology and Geriatry); Scheu, M. (Medical Laser Center Luebeck (Germany))

    Selective plaque ablation with laser radiation at 405-530 nm in vitro has been reported. The possibilities are investigated of a new pulsed dye laser device for in vivo recanalization of arteries in ischemic lower limbs and stenoses/occlusions of arterio-venous hemo-dialysis shunt fistulae. A specially designed 9F or 7F multifiber catheter was used for treatment of 10 patients with lower limb artery obliterations and 11 patients with malfunctioning hemodialysis access fistulae (HAF). The recanalization technical success was 5/5 in the iliac arteries (IA), 4/5 in the superficial femoral arteries (SFA), and 11/11 in the HAF. Early re-occlusions occurred in one SFA and IA, respectively, caused by very bad run-off. There was one clinically insignificant SFA perforation. Additional balloon angioplasty was considered necessary in 10/16 lesions. Mean ankle-arm index increased from 0.68 to 0.97. With two exceptions all HAF patients were re-integrated in the dialysis program. Pulsed dye laser angioplasty promises to be an effective and fast method for plaque ablation debulking. The first clinical experience confirms previous in vitro results. In particular laser recanalization may become the method of choice for treatment of rigid HAF obstructions and it seems to be superior to vascular surgery or balloon angioplasty alone. (author). 15 refs.; 2 figs.

  1. Ultraviolet laser ablation of fluorine-doped tin oxide thin films for dye-sensitized back-contact solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Huan [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei, 430074 (China); Fu, Dongchuan [ARC Centre of Excellence for Electromaterials Science, Department of Materials Engineering and School of Chemistry, Monash University, Clayton Victoria, 3800 (Australia); Jiang, Ming [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei, 430074 (China); Duan, Jun, E-mail: duans@hust.edu.cn [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei, 430074 (China); Zhang, Fei; Zeng, Xiaoyan [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei, 430074 (China); Bach, Udo [ARC Centre of Excellence for Electromaterials Science, Department of Materials Engineering and School of Chemistry, Monash University, Clayton Victoria, 3800 (Australia)

    2013-03-01

    In this study, laser ablation of a fluorine-doped tin oxide (FTO) thin film on a glass substrate was conducted using a 355 nm Nd:YVO{sub 4} ultraviolet (UV) laser to obtain a 4 × 4 mm microstructure. The microstructure contains a symmetric set of interdigitated FTO finger electrodes of a monolithic back-contact dye-sensitized solar cell (BC-DSC) on a common substrate. The effects of UV laser ablation parameters (such as laser fluence, repetition frequency, and scanning speed) on the size precision and quality of the microstructure were investigated using a 4 × 4 orthogonal design and an assistant experimental design. The incident photon-to-electron conversion efficiency and the current–voltage characteristics of the BC-DSC base of the interdigitated FTO finger electrodes were also determined. The experimental results show that an FTO film microstructure with high precision and good quality can be produced on a glass substrate via laser ablation with high scanning speed, high repetition frequency, and appropriate laser fluence. - Highlights: ► The ablation width and depth generally depend on the laser fluence. ► The scanning speed and the repetition frequency must match each other. ► Slight ablation of the glass substrate can completely remove F-doped tin oxide.

  2. Optimization of lasing in an inverted-opal titania photonic crystal cavity as an organic solid-state dye-doped laser.

    Science.gov (United States)

    Zhang, Dingke; Chen, Shijian; Jiang, Maohua; Ye, Lijuan

    2014-11-10

    Lasing performance of a dye-doped laser by encapsulating orange fluorescent dye 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) with different concentrations in a highly ordered three-dimensional (3D) inverted-opal titania (TiO2) photonic crystal (PC) microcavity was studied. The lasing threshold and laser quality were improved by optimizing the concentration of the laser dye DCM. When the concentration of DCM is optimized to 10-4  mol/l, the photoluminescence (PL) efficiency of DCM is sufficient to achieve lasing emission and meanwhile no fluorescence quantum quenching occurs. Therefore, the emission spectrum was greatly narrowed and the threshold was significantly improved, which reached 0.8  mJ pulse-1 cm-2. Our findings are promising results toward the realization of fabricating a highly efficient low-threshold organic laser.

  3. Far-Field Patterns from Dye-Doped Planar-Aligned Nematic Liquid Crystals Under nanosecond Laser Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lukishova, S.G.; Lepeshkin, N.; Boyd, R.W.; Marshall, K.L.

    2006-08-18

    High-definition patterns were observed under 10-Hz-pulse-repetition-rate, nanosecond laser irradiation of azodye-doped planar-nematic liquid crystal layers at incident intensities I ~ 5-10 MW/cm^2 in a single beam configuration and without any feedback involved. An incident polarization parallel to the nematic director was used. Under periodic pulsed laser irradiation, far-field beam patterns at the output of a dye-doped liquid crystal layer changed kaleidoscopically from rings and stripes to multiple hexagons. This pattern-formation regime had a buildup time of several seconds to minutes. We explain the observed effect by diffraction of the laser beam on light-induced micrometer-size inhomogeneities inside the liquid crystal layer with absorption and refraction properties different from the surrounding area. Possible mechanisms of the formation of the inhomogeneities are discussed.

  4. Replica symmetry breaking in specially designed TiO$_{2}$ nanoparticles-based dye-colloidal random laser

    CERN Document Server

    Pincheira, Pablo I R; Carreño, Sandra J M; Fewo, Serge I; Moura, André L; Raposo, Ernesto P; Gomes, Anderson S L; de Araújo, Cid B

    2015-01-01

    Replica symmetry breaking (RSB) is a concept inherent to the theory of spin glasses and complex systems, which describes how identical systems prepared under identical initial conditions can reach different states. RSB was predicted and demonstrated, for the first time in any physical system, using random lasers (RLs) operating in the coherent feedback regime. However, attempts to show RSB in RLs operating in the incoherent feedback regime based on colloidal solution of dye and scatterer particles failed. In the present letter, by using specially designed nanoparticles scatterers which prevents photodegradation of the dye, we present clear evidence of RSB in a RL operating in the incoherent feedback regime based on ethanol solution of Rhodamine 6G and amorphous TiO$_{2}$ nanoparticles.

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    This paper presents the effect of a low refractive index ring in the Yb-doped rod-type photonic crystal fibre core on the guided mode propagation and analyzed through a spatial and spectral amplifier model. The ring provides a higher differential overlap between the fundamental mode (FM...

  6. Doppler-limited dye laser excitation spectroscopy of the DSO radical

    Science.gov (United States)

    Ohashi, Nobukimi; Kakimoto, Masao; Saito, Shuji; Hirota, Eizi

    1980-11-01

    The Ã2A'(003) ← X˜2A″(000) vibronic transition (16 370 to 16 425 cm -1) of the DSO radical in studied by Doppler-limited dye laser excitation spectroscopy. DSO is produced in a flow system by reacting the products of a microwave discharge in O 2 with D 2S. About 637 observed lines are assigned to 987 transitions of the 19 subbands: K' a ← K″ a = 6 ← 5, 5 ← 4, 4 ← 3, 3 ← 2, 2 ← 1, 1 ← 0, 0 ← 1, 1 ← 2, 2 ← 3, 3 ← 4, 0 ← 0, 1 ← 1, 2 ← 2, 3 ← 3, 4 ← 4, 3 ← 1, 2 ← 0, 0 ← 2, and 1 ← 3. They are analyzed to determine rotational constants, centrifugal distortion constants, and spin-rotation constants for both the ground and the excited electronic states. The band origin obtained is 16 413.874 (2.5σ = 0.002) cm -1. The rotational constants determined are combined with the previous result on HSO (M. Kakimoto et al., J. Mol. Spectrosc.80, 334-350 (1980)) to calculate the structural parameters for this radical in both the states: r( SO) = 1.494(5) Å, r( SH) = 1.389(5) Å, and ∠HSO = 106.6(5)° for the X˜2A″ state, and r( SO) = 1.661(10) Å, r( SH) = 1.342(8) Å, and ∠HSO = 95.7(21)° for the Ã2A'(003) state, where values in parentheses denote 2.5σ.

  7. Pulsed dye laser and intralesional bleomycin for the treatment of recalcitrant cutaneous warts.

    Science.gov (United States)

    Dobson, Joelle S; Harland, Christopher C

    2014-02-01

    Viral warts are a common ailment. Clinicians often combine multiple treatments to boost efficacy. One such novel combination is pulsed dye laser with bleomycin intralesionally (PDL + BI), described for the successful treatment of single hand warts. To evaluate PDL + BI for the treatment of poor prognosis hand and foot warts. This 4-year retrospective case series examined the efficacy of PDL + BI used consecutively on patients whose warts were treated with this modality alone. PDL 595 nm was used in stacking mode to achieve hemorrhagic blistering prior to intralesional bleomycin (1 mg/ml normal saline). Twenty cases (65% male, age 13-62, mean age 42) were identified. Two (10%) were immunocompromised. Twenty five percent of warts affected hands, 55% feet, 20% both. Thirty five percent were solitary >1 cm(2) , 40% were multiple or mosaic verucae. The mean duration was 5.1 years (0.5-15). Seventy five percent received local anesthetic. Mean number of treatments was two. Post-operative pain varied from none to severe, sometimes causing difficulty in walking. Blistering and crusting disappeared after 17 days (range 7-42). Outcome had a mean follow-up of 24 months (3-53) with 60% complete response, 15% partial, 25% no response. Mean satisfaction level was 7 (range 0-10, 10 highest). Outcome was better with local anesthetic (complete response 75%) as it permitted more aggressive treatment. Patients that had both anesthetic and repeat treatment sessions experienced 92% complete response. PDL + BI offers a novel method for treatment of recalcitrant warts, but local anesthetic and repeat treatments are recommended. © 2013 Wiley Periodicals, Inc.

  8. Experience With Esthetic Reconstruction of Complex Facial Soft Tissue Trauma; Application of the Pulsed Dye Laser

    Directory of Open Access Journals (Sweden)

    Ebrahimi

    2014-08-01

    Full Text Available Background Facial soft tissue injury can be one of the most challenging cases presenting to the plastic surgeon. The life quality and self-esteem of the patients with facial injury may be compromised temporarily or permanently. Immediate reconstruction of most defects leads to better restoration of form and function as well as early rehabilitation. Objectives The aim of this study was to present our experience in management of facial soft tissue injuries from different causes. Patients and Methods We prospectively studied patients treated by plastic surgeons from 2010 to 2012 suffering from different types of blunt or sharp (penetrating facial soft tissue injuries to the different areas of the face. All soft tissue injuries were treated primarily. Photography from all patients before, during, and after surgical reconstruction was performed and the results were collected. We used early pulsed dye laser (PDL post-operatively. Results In our study, 63 patients including 18 (28.5% women and 45 (71.5% men aged 8-70 years (mean 47 years underwent facial reconstruction due to soft tissue trauma in different parts of the face. Sharp wounds were seen in 15 (23% patients and blunt trauma lacerations were seen in 52 (77% patients. Overall, 65% of facial injuries were repaired primary and the remainder were reconstructed with local flaps or skin graft from adjacent tissues. Postoperative PDL therapy done two weeks following surgery for all scars yielded good results in our cases. Conclusions Analysis of the injury including location, size, and depth of penetration as well as presence of associated injuries can aid in the formulation of a proper surgical plan. We recommend PDL in the early post operation period (two weeks after suture removal for better aesthetic results.

  9. Synthesis and characterization of gold graphene composite with dyes as model substrates for decolorization: a surfactant free laser ablation approach.

    Science.gov (United States)

    Sai Siddhardha, R S; Lakshman Kumar, V; Kaniyoor, Adarsh; Sai Muthukumar, V; Ramaprabhu, S; Podila, Ramakrishna; Rao, A M; Ramamurthy, Sai Sathish

    2014-12-10

    A facile surfactant free laser ablation mediated synthesis (LAMS) of gold-graphene composite is reported here. The material was characterized using transmission electron microscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, powdered X-ray diffraction, Raman spectroscopy, Zeta potential measurements and UV-Visible spectroscopic techniques. The as-synthesized gold-graphene composite was effectively utilized as catalyst for decolorization of 4 important textile and laser dyes. The integration of gold nanoparticles (AuNPs) with high surface area graphene has enhanced the catalytic activity of AuNPs. This enhanced activity is attributed to the synergistic interplay of pristine gold's electronic relay and π-π stacking of graphene with the dyes. This is evident when the Rhodamine B (RB) reduction rate of the composite is nearly twice faster than that of commercial citrate capped AuNPs of similar size. In case of Methylene blue (MB) the rate of reduction is 17,000 times faster than uncatalyzed reaction. This synthetic method opens door to laser ablation based fabrication of metal catalysts on graphene for improved performance without the aid of linkers and surfactants.

  10. Low-pulse energy Q-switched Nd:YAG laser treatment for hair-dye-induced Riehl's melanosis.

    Science.gov (United States)

    On, Hye Rang; Hong, Won Jin; Roh, Mi Ryung

    2015-06-01

    Riehl's melanosis, a form of dermatitis characterized by reticulate pigmentation, typically presents as a gray-brown to black hyperpigmentation on the face and neck. Among the various etiologic factors suggested, photoallergic reaction and pigmented contact dermatitis resulting from exposure to drugs, coal tar dyes, optical whitener, or other ingredients found in cosmetics are believed to be the major contributing factors in this disease. The histopathological features of Riehl's melanosis mainly consist of pigmentary incontinence along with infiltration of numerous dermal melanophages and lymphohistiocytes.1,2 Additionally, notable clinical improvements in the treatment of this condition have been reported for intense pulsed light (IPL) therapy, in comparison to long-term topical application of bleaching agents.2 Here, we report the cases of two Asian patients treated with a low-pulse energy 1,064-nm Q-switched (QS) Nd:YAG laser for hair dye-induced Riehl's melanosis on the face and neck. In conclusion, we observed that Riehl's melanosis on the face and neck was effectively and safely treated with a low-pulse energy 1,064-nm QS Nd:YAG laser. We suggest that this method can be used in Asian patients with Riehl's melanosis at risk of postinflammatory hyperpigmentation from excessive light or laser energy delivery.

  11. Thermomechanical and Photophysical Properties of Crystal-Violet-Dye/H2O Based Dissolutions via the Pulsed Laser Photoacoustic Technique

    Directory of Open Access Journals (Sweden)

    Vicente Torres-Zúñiga

    2014-01-01

    Full Text Available Different thermoelastic parameters, for example, the acoustic attenuation and the speed of sound, are fundamental for instrumental calibration and quantitative characterization of organic-based dissolutions. In this work, these parameters as functions of the concentration of an organic dye (crystal-violet: CV in distillated water (H2O based dissolutions are investigated. The speed of sound was measured by the pulsed-laser photoacoustic technique (PLPA, which consists in the generation of acoustic-waves by the optical absorption of pulsed light in a given material (in this case a liquid sample. The thermally generated sound-waves traveling through a fluid are detected with two piezoelectric sensors separated by a known distance. An appropriate processing of the photoacoustic signals allows an adequate data analysis of the generated waves within the system, providing an accurate determination of the speed of sound as function of the dye-concentration. The acoustic attenuation was calculated based on the distance of the two PZT-microphones to an acoustic-source point and performing linear-fitting of the experimental data (RMS-amplitudes as function of the dye-concentration. An important advantage of the PLPA-method is that it can be implemented with poor or null optical transmitting materials permitting the characterization of the mechanical and concentration/aggregate properties of dissolved organic compounds.

  12. Morphoelastic rods

    CERN Document Server

    Tiero, Alessandro

    2014-01-01

    We propose a mechanical theory describing elastic rods which, like plant organs, can grow and can change their intrinsic curvature and torsion. The equations ruling accretion and remodeling are obtained by combining balance laws involving non-standard forces with constitutive prescriptions filtered by a dissipation principle that takes into account both standard and non-standard working.

  13. Laser doppler and radar interferometer for contactless measurements on unaccessible tie-rods on monumental buildings: Santa Maria della Consolazione Temple in Todi

    Science.gov (United States)

    Gioffré, M.; Cavalagli, N.; Pepi, C.; Trequattrini, M.

    2017-01-01

    Non-contact measurements can be effectively used in civil engineering to assess the variation of structural performance with time. In the last decades this approach has received considerable interests from researchers working in the field of structural health monitoring (SHM). Indeed, non-contact measurements are very attractive because it is possible to perform non intrusive and non destructive investigations even being at a significant distance from the targets. Within this context, contactless measurements of the tie-rod vibrations in the Santa Maria della Consolazione Temple in Todi (Italy) are presented in this paper. In particular, laser vibrometer and radar interferometer measurements are used to estimate natural frequencies and mode shapes. This information is crucial to obtain the tensile axial force in the tie-rods, which can be used as an indicator of structural integrity or possible failure. Furthermore, a novel approach is proposed where drones (Unmanned Aerial Vehicles) can be successfully used to improve the effectiveness and the accuracy of the experimental activities.

  14. Enhancement of photoconversion efficiency in dye-sensitized solar cells exploiting pulsed laser deposited niobium pentoxide blocking layers

    Energy Technology Data Exchange (ETDEWEB)

    Sacco, Adriano, E-mail: adriano.sacco@iit.it [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Di Bella, Maurizio Salvatore [Department of Energy, Information Engineering and Mathematical Models (DEIM), Thin Films Laboratory, Università di Palermo, Viale delle Scienze, Building 9, 90128 Palermo (Italy); Gerosa, Matteo [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Applied Science and Technology Department (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Chiodoni, Angelica; Bianco, Stefano [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Mosca, Mauro; Macaluso, Roberto; Calì, Claudio [Department of Energy, Information Engineering and Mathematical Models (DEIM), Thin Films Laboratory, Università di Palermo, Viale delle Scienze, Building 9, 90128 Palermo (Italy); Pirri, Candido Fabrizio [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Applied Science and Technology Department (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2015-01-01

    Among all the photovoltaic technologies developed so far, dye-sensitized solar cells are considered as a promising alternative to the expensive and environmentally unfriendly crystalline silicon-based solar cells. One of the possible strategies employed to increase their photovoltaic efficiency is to reduce the charge recombination at the cell conductive substrate through the use of a compact blocking layer. In this paper, we report on the fabrication and characterization of dye-sensitized solar cells employing niobium pentoxide (Nb{sub 2}O{sub 5}) thin film blocking layer deposited through the pulsed laser deposition technique on conductive substrates. The careful selection of the optimal film thickness led to a 30% enhancement of the photoconversion efficiency with respect to reference cells fabricated without blocking layer. Open circuit voltage decay and electrochemical impedance spectroscopy techniques proved that the effective suppression of the charge recombination occurring at the substrate/electrolyte interface represents the main reason for the improvement of the photovoltaic efficiency. - Highlights: • Niobium pentoxide thin films were fabricated through pulsed laser deposition. • The deposited films were employed as recombination blocking layer in DSCs. • The selection of the optimal film thickness led to the enhancement of the efficiency.

  15. Analytical model of transient temperature and thermal stress in continuous wave double-end-pumped laser rod: Thermal stress minimization study

    Indian Academy of Sciences (India)

    Khalid S Shibib; Mayada M Tahir; Haqi I Qatta

    2012-08-01

    A time-dependent analytical thermal model of the temperature and the corresponding induced thermal stresses in continuous wave double-end-pumped laser rod are derived from the first principle using the integral transform method. The aim of the paper is to study the effect of increasing the pumping powers while the laser crystals are still in the safe zone (i.e. far away from failure stress) and to suitably choose a crystal that achieves this task. The result of this work is compared with a well-verified finite element solution and a good agreement has been found. Some conclusions are obtained: Tm:YAP crystal, which has high thermal conductivity, low expansion coefficient, low absorption coefficient, low thermal factor and low product of /(1−), is the best choice to reduce induced stress although it is responded and brought to thermal equilibrium faster than the other types of crystal usually used in the end-pumped solid-state laser.

  16. Stress analysis and optimization of Nd:YAG pulsed laser processing of notches for fracture splitting of a C70S6 connecting rod

    Energy Technology Data Exchange (ETDEWEB)

    Kou, Shuqing; Gao, Yan; Zhao, Yong; Lin, Baojun [Jilin University, Changchun (China)

    2017-05-15

    The pulsed laser pre-processing of a notch as the fracture initiation source for the splitting process is the key mechanism of an advanced fracture splitting technology for C70S6 connecting rods. This study investigated the stress field of Nd:YAG pulsed laser grooving, which affects the rapid fracture initiation at the notch root and the controlled crack extension in the critical fracture splitting quality, to improve manufacturing quality. Thermal elastic-plastic incremental theory was applied to build the finite element analysis model of the stress field of pulsed laser grooving for fracture splitting based on the Rotary-Gauss body heat source. The corresponding numerical simulation of the stress field was conducted. The changes and distributions of the stress during pulsed laser grooving were examined, the influence rule of the primary technological parameters on the residual stress was analyzed, and the analysis results were validated by the corresponding cutting experiment. Results showed that the residual stress distribution was concentrated in the Heat-affected zone (HAZ) near the fracture splitting notch, which would cause micro-cracks in the HAZ. The stress state of the notch root in the fracture initiation direction was tensile stress, which was beneficial to the fracture initiation and the crack rapid extension in the subsequent fracture splitting process. However, the uneven distribution of the stress could lead to fracture splitting defects, and thus the residual stress should be lowered to a reasonable range. Decreasing the laser pulse power, increasing the processing speed, and lowering the pulse width can lower the residual stress. Along with the actual production, the reasonable main technological parameters were obtained.

  17. Time-dependent analytical thermal model to investigate thermally induced stresses in quasi-CW-pumped laser rods

    CSIR Research Space (South Africa)

    Bernhardi, EH

    2008-01-01

    Full Text Available One of the main problems that limit the power scaling of diode-end-pumped solid-state lasers is the generation of heat inside the laser gain medium which can ultimately cause fracture. In this paper a time-dependent analytical thermal model...

  18. Outcomes of childhood hemangiomas treated with the pulsed-dye laser with dynamic cooling: a retrospective chart analysis.

    Science.gov (United States)

    Rizzo, Carina; Brightman, Lori; Chapas, Anne M; Hale, Elizabeth K; Cantatore-Francis, Julie L; Bernstein, Leonard J; Geronemus, Roy G

    2009-12-01

    Laser treatment of childhood hemangiomas remains controversial. Previous studies have used outdated technology, resulting in a potential overrepresentation of adverse outcomes. To evaluate outcomes of hemangiomas treated with the most current laser technology. A retrospective chart analysis of 90 patients with a median age of 3.0 months and a total of 105 hemangiomas were enrolled over a 2.5-year period. All were treated with the 595-nm long-pulse pulsed-dye laser (LP-PDL) with dynamic epidermal cooling at 2- to 8-week intervals depending on the stage of growth. Exclusion criteria were previous laser, surgical, or corticosteroid treatment. Three reviewers assessed outcomes. Near-complete or complete clearance in color were achieved for 85 (81%) and in thickness for 67 (64%) hemangiomas. There was no scarring or atrophy. Ulceration occurred in one case and resolved during treatment. Hyperpigmentation and hypopigmentation occurred in 4% and 14% of hemangiomas, respectively. Early treatment of childhood hemangiomas with the 595-nm LP-PDL with dynamic cooling may reduce the proliferative phase and result in excellent rates of clearing and few adverse events.

  19. Structural and spectroscopic characterization of Ce0.4Zr0.6O2 crystalline rods grown by the Laser Floating Zone method

    Directory of Open Access Journals (Sweden)

    Várez, A.

    2008-06-01

    Full Text Available A structural and spectroscopic characterization of crystalline rods of Ce0.4Zr0.6O2 grown by the laser floating zone (LFZ method is presented. A precursor rod of Ce0.4Zr0.6O2 composition was sintered at 1500 ºC in air atmosphere and then processed by the LFZ technique with a CO2 laser. The processed material was characterized by XRD, SEM and Raman spectroscopy. In the as-grown, dark-color processed rod, the Raman spectrum evolves radially from a t’-like one, corresponding to Ce0.37Zr0.63O2 composition, at the edge of the rod, to a very broad and weak, cubic-like one, at the center. The degree of cerium reduction and oxygen non-stoichiometry were determined through measurements of the electronic Raman spectrum of Ce3+. A strong Ce3+ signal was found at the core of the rod, indicating strong reduction, whereas no Ce3+ signal was detected at the edge. To restore oxygen and Ce4+ content a section of the fiber was reoxidized at 620 ºC for 24 h. A very homogeneous spectrum was found in the reoxidized sample, that was assigned to a t’-phase of composition Ce0.42Zr0.58O2.Presentamos una caracterización estructural y espectroscópica de fibras cristalinas de Ce0.4Zr0.6O2 crecidas mediante fusión zonal asistida por láser (LFZ. Una barra del material precursor, de composición Ce0.4Zr0.6O2, fue sinterizada a 1500 ºC en atmósfera de aire y después procesada por LFZ con un láser de CO2. El material procesado fue caracterizado por difracción de rayos X, microscopía electrónica de barrido y espectroscopía Raman. En la fibra recién procesada, de color gris oscuro, el espectro Raman varía radialmente desde un espectro de tipo t’, correspondiente a una composición Ce0.37Zr0.63O2, en el borde de la fibra, hasta un espectro muy ensanchado y débil, de aspecto cúbico, en el centro. El grado de reducción del cerio y la no estequiometría del oxígeno se determinaron a través de las medidas del Raman electrónico del Ce3+. La señal de Ce3

  20. CONTROL ROD

    Science.gov (United States)

    Zinn, W.H.; Ross, H.V.

    1958-11-18

    A control rod is described for a nuclear reactor. In certaln reactor designs it becomes desirable to use a control rod having great width but relatively llttle thickness. This patent is addressed to such a need. The neutron absorbing material is inserted in a triangular tube, leaving volds between the circular insert and the corners of the triangular tube. The material is positioned within the tube by the use of dummy spacers to achleve the desired absorption pattern, then the ends of the tubes are sealed with suitable plugs. The tubes may be welded or soldered together to form two flat surfaces of any desired width, and covered with sheetmetal to protect the tubes from damage. This design provides a control member that will not distort under the action of outside forces or be ruptured by gases generated within the jacketed control member.

  1. Lasing behavior in a liquid spherical dye laser containing highly scattering nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, H.; Nishiya, M.; Tanosaki, S. [Department of Electrical and Electronic Engineering, Faculty of Engineering, Iwate University, 4-3-5 Ueda, Morioka 020 (Japan); Inaba, H. [Department of Electronics, Tohoku Institute of Technology, 35-1 Yagiyama, Kasumi-Cho, Taikaku-Ku, Sendai 982 (Japan)

    1996-02-01

    With the addition of scattering nanoparticles to dye-doped spherical droplets, lasing has been observed with well-defined thresholds in input{endash}output data. One-order or more magnitude enhancement of peak intensity from droplet emission has been obtained with certain (optimum) additive scattering particles compared with nonadditive scattering particles (neat dye-doped droplets). Characteristics of input{endash}output intensities, emission spectra (with wavelength shifts), and spectral linewidths are reported experimentally, depending on additive quantities of scattering nanoparticles. {copyright} {ital 1996 Optical Society of America.}

  2. The shape effect of Au particles on random laser action in disordered media of Rh6G dye doped with PMMA polymer

    Science.gov (United States)

    Yin, Jiajia; Feng, Guoying; Zhou, Shouhuan; Zhang, Hong; Wang, Shutong; Zhang, Hua

    2016-10-01

    Random laser actions in a disordered media based on polymethyl methacrylate (PMMA) polymer doped with Rh6G dye and Au nanoparticles have been demonstrated. It was observed that the shape of Au nanoparticles can tune the spectral central position of the random laser action. It was also seen that the shape of Au nanoparticles strongly affects the pump threshold. Comparing nanosphere- and nanorod-based systems, the nanorod-based one exhibited a lower threshold.

  3. Contribution to the development of the dye laser emitting in the near infrared: application to the investigation of the laser characteristics of a series of cyanines. [Thesis

    Energy Technology Data Exchange (ETDEWEB)

    Hirth, A.

    1974-08-07

    Laser emission achieved by means of fluorescent substances is reviewed. Qualitative results were obtained with a diagram of the molecule energy level, and quantitative results were obtained with the aid of formulas for the gain and critical inversion as a function of both the spectroscopic and kinetic parameters of the molecule. For flash light devices, the development of rapid discharge circuits and coaxial flash tube light sources allowed a certain number of arrangements to be designed. Laser emission of a series of tricarbocyanine molecules could be obtained via direct excitation by means of flash tube light sources. The emission wavelengths were compared with the emitted luminous efficiency. The influence of the physico-chemical parameters on the emission characteristics is detailed. Methods applied to dye lasers for the visible area were extended to those for the near infrared. Results were obtained either by tuning the emission wavelength or by generation of ultra-short infrared light pulses by mode locking in a cavity applied to three lasers emitting at 800, 870, and 950 nm.

  4. Fluorescence, Decay Time, and Structural Change of Laser Dye Cresyl Violet in Solution due to Microwave Irradiation at GSM 900/1800 Mobile Phone Frequencies

    Directory of Open Access Journals (Sweden)

    Fuat Bayrakceken

    2012-01-01

    Full Text Available Microwave irradiation at GSM 900/1800 MHz mobile phone frequencies affects the electronic structure of cresyl violet in solution. These changes are important because laser-dye cresyl violet strongly bonds to DNA- and RNA-rich cell compounds in nerve tissues. The irradiation effects on the electronic structure of cresyl violet and its fluorescence data were all obtained experimentally at room temperature. For most laser dyes, this is not a trivial task because laser dye molecules possess a relatively complex structure. They usually consist of an extended system of conjugated double or aromatic π-bonds with attached auxochromic (electron donating groups shifting the absorption band further towards longer wavelength. Because of the intrinsically high degree of conjugation, the vibrational modes of the molecular units couple strongly with each other. We found that the fluorescence quantum yield was increased from to due to intramolecular energy hopping of cresyl violet in solution which is exposed to microwave irradiation at mobile phone frequencies, and the photonic product cannot be used as a laser dye anymore.

  5. Intense pulsed light vs. long-pulsed dye laser treatment of telangiectasia after radiotherapy for breast cancer: a randomized split-lesion trial of two different treatments

    DEFF Research Database (Denmark)

    Nymann, P.; Hedelund, L.; Hædersdal, Merete

    2009-01-01

    Background Chronic radiodermatitis is a common sequela of treatment for breast cancer and potentially a psychologically distressing factor for the affected women. Objectives To evaluate the efficacy and adverse effects of treatments with a long-pulsed dye laser (LPDL) vs. intense pulsed light (IPL...

  6. Effects of lower fluence pulsed dye laser irradiation on production of collagen and the mRNA expression of collagen relative gene in cultured fibroblasts in vitro

    Institute of Scientific and Technical Information of China (English)

    YU Hai-yan; CHEN Da-fang; WANG Qi; CHENG Hao

    2006-01-01

    Background Lower fluence of 585-nm flashlamp-pumped pulsed dye laser has been successfully used as a nonablative technique in the treatment of wrinkles. The objective of this study was to evaluate the effect of the pulsed dye laser (585 nm) on the production of collagen and the mRNA expression of collagen related gene in fibroblasts in vitro.Methods Cultured fibroblasts were treated with a 585-nm flashlamp-pumped pulsed dye laser ( fluence 3 J/cm2,4 J/cm2, spot size 7 mm, pulse duration 450 μs). The production of collagen and the mRNA expression of transforming growth factor (TGF)-β1, SMAD2, SMAD3, SMAD4, SMAD7 and type I procollagen α1, α2 in fibroblasts were investigated by colorimetry or real time polymerase chain reaction.Results The production of collagen was significantly up-regulated after treatment with a 585-nm flashlamp-pumped pulsed dye laser with a fluence of 3 J/cm2 (P <0.001). The mRNA expression of TGF- β1,SMAD2, SMAD3, SMAD4, SMAD7 and procollagen I was significantly up-regulated after treatment with a 585-nm flashlamp-pumped pulsed dye laser with a fluence of 3 J/cm2 (P <0.001). No significant difference of mRNA expression of SMAD2, SMAD3, SMAD4, SMAD7 and type I procollagen was found between controls and fibroblasts treated with pulsed dye laser with a fluence of 4 J/cm2 (P >0.05).Conclusions Lower fluence (3 J/cm2) pulsed dye laser increased the collagen production in fibroblasts by up-regulating TGF-β1, SMAD2, SMAD3, SMAD4, SMAD7 and type I procollagen mRNA expression. These may be the reason it can be effectively used in the treatment of wrinkles.

  7. Passive adoptive transfer of antitumor immunity induced by laser-dye-immunoadjuvant treatment in a rat metastatic breast cancer model

    Science.gov (United States)

    Chen, Wei R.; Liu, Hong; Singhal, Anil K.; Nordquist, Robert E.

    2000-06-01

    The ideal cancer treatment modalities should not only cause tumor regression and eradication but also induce a systemic anti-tumor immunity. This is essential for control of metastatic tumors and for long-term tumor resistance. Laser immunotherapy using a laser, a laser-absorbing dye and an immunoadjuvant has induced such a long-term immunity in treatment of a mammary metastatic tumor. The successfully treated rats established total resistance to multiple subsequent tumor challenges. For further mechanistic studies of the antitumor immunity induced by this novel treatment modality, passive adoptive transfer was performed using splenocytes as immune cells. The spleen cells harvested from successfully treated tumor-bearing rats provided 100% immunity in the naive recipients. The passively protected first cohort rats were immune to tumor challenge with an increased tumor dose; their splenocytes also prevented the establishment of tumor in the second cohort of naive recipient rats. This immunity transfer was accomplished without the usually required T-cell suppression in recipients.

  8. Efficient and high-power green beam generation by frequency doubling of acousto-optic Q-switched diode-side pumped Nd:YAG rod laser in a coupled cavity

    Indian Academy of Sciences (India)

    S K Sharma; A J Singh; P K Mukhopadhyay; S M Oak

    2010-11-01

    A 52-W green laser at 532 nm by extra-cavity second-harmonic generation in a coupled-cavity configuration is demonstrated. The fundamental laser is a diode-side-pumped acousto-optic (AO) Q-switched Nd:YAG rod laser producing 84 W of average power at 1064 nm at 8 kHz repetition rate. Type-II phase-matched polished KTP crystal is used as the nonlinear crystal for second-harmonic generation. The individual green pulse width is 50 ns and the fundamental to second harmonic conversion efficiency is 61.8%.

  9. Ability of laser fluorescence device associated with fluorescent dyes in detecting and quantifying early smooth surface caries lesions

    Science.gov (United States)

    Mendes, Fausto M.; de Oliveira, Elisabeth; de Faria, Dalva L. A.; Nicolau, José

    2006-03-01

    A laser fluorescence (LF) device is a portable tool, but it does not measure minor mineral changes. Our in vitro study aim is to propose the association of an LF with two fluorescent dyes and to evaluate the performance in detecting and quantifying early demineralization. Artificial caries lesions are created in 40 primary canine teeth using a demineralizing solution (pH=4.8) for 12, 24, 48, and 96 h. LF measurements are performed with DIAGNOdent after demineralization in these samples and in 20 sound primary teeth. Measurements with LF with 0.2-mM tetrakis(N-methylpyridyl)porphyrin (LF TMPyP) and with 4-mM protoporphyrin IX (LF PPIX) are made. The amount of calcium loss is determined by atomic emission spectrometry. A correlation between LF and LF with dyes and mineral loss and receiver operating characteristics analysis are performed, as well as comparisons of sensitivity, specificity, and accuracy values. Significant correlation is obtained with LF TMPyP and mineral loss of lesions demineralized for 24, 48, and 96 h. Better performance is achieved with LF TMPyP for all parameters than with LF alone. LF PPIX does not present good results. In conclusion, LF TMPyP provides good performance in detecting and quantifying very early enamel caries lesions.

  10. Optical properties and chemical behavior of Laser-dye Coumarin-500 and the influence of atmospheric corona discharges.

    Science.gov (United States)

    Keskin, S Sinan; Aslan, Necdet; Bayrakçeken, Fuat

    2009-03-01

    Structure elucidation of Coumarin-500 Laser-dye in cyclohexane at room temperature has been studied by UV-Vis, Raman, and FTIR spectroscopic techniques. Optical properties and chemical behavior under the influence of atmospheric positive electric pulsed corona discharges were also examined. The effects of UV-Vis irradiation changed some optical parameters, such as decrease in optical density on the absorption spectrum and formation of photoproducts, due to the chromaticity removal. No significant optical changes were observed in the light absorption upon UV-irradiation but large changes in absorption spectrum were observed after positive electric corona discharge treatments, FTIR and Raman spectra in non-polar solvent are recorded and interpreted.

  11. Ultraviolet absorption spectroscopy in optically dense fireballs using broadband second-harmonic generation of a pulsed modeless dye laser.

    Science.gov (United States)

    Soo, Michael; Glumac, Nick

    2014-01-01

    Broadband frequency doubling of a modeless dye laser pulse is used to enable single-shot absorption spectroscopy in the ultraviolet for optically dense, energetic-materials fireball applications. Band widths of approximately 1-3 nm are generated in the 226 and 268 nm regions using a doubling crystal. Strong focusing of the fundamental beam onto the crystal is found to be sufficient to achieve 1-5% conversion efficiency with a pulse intensity sufficient to saturate the array detector even after 75% attenuation through the fireball. The technique is demonstrated with nitric oxide (NO) absorption in a gas cell and is then used to perform the first detection and temperature fitting of aluminum monofluoride (AlF) and magnesium monofluoride (MgF) in a fireball environment.

  12. Inertial deposition effects: a study of aerosol mechanics in the trachea using laser Doppler velocimetry and fluorescent dye.

    Science.gov (United States)

    Corcoran, T E; Chigier, Norman

    2002-12-01

    This study characterizes the axial velocity and axial turbulence intensity patterns noted in the tracheal portion of a cadaver-based throat model at two different steady flow rates (18.1 and 41.1 LPM.) This characterization was performed using Phase Doppler Interferometry (Laser Doppler Velocimetry). Deposition, as assessed qualitatively using fluorescent dye, is related to the position of the laryngeal jet within the trachea. The position of the jet is dependent on the downstream conditions of the model. It is proposed therefore that lung/airway conditions may have important effects on aerosol deposition within the throat. There is no correspondence noted between regions of high axial turbulence intensity and deposition.

  13. Clinical feasibility of various optical instruments for quantitative evaluation of pulsed-dye laser treatment of port wine stain skin

    Science.gov (United States)

    Kim, Chang-Seok; Jung, Byungjo; Choi, Bernard; Verkruysse, Wim; Zhang, Rong; Nelson, John S.

    2005-04-01

    For quantitative prediction and evaluation of pulsed dye laser therapy of port wine stain (PWS) skin, the CIE L*a*b* color difference, ΔE*, has been utilized to characterize numerically the color differences between normal untreated and treated PWS skin. Three optical instruments (Minolta chromameter CR-200, a cross-polarized diffuse reflectance imaging system, and visual reflectance spectrometers) are compared to investigate their clinical feasibility for quantitative color assessment. Compared to the chromameter as a standard measurement instrument, other instruments also provide valuable measurements of skin color for the relative quantification of PWS treatment outcome. The fiber-optic visual reflectance spectrometer is preferable for continuous measurement of a small area of skin. The cross-polarized imaging system is useful as a simple non-contact measurement technique to provide spatially resolved color difference images.

  14. Direct Analysis of Textile Fabrics and Dyes Using IR Matrix-Assisted Laser Desorption Electrospray Ionization (MALDESI) Mass Spectrometry

    OpenAIRE

    Cochran, Kristin H.; Barry, Jeremy A.; Muddiman, David C.; Hinks, David

    2012-01-01

    The forensic analysis of textile fibers uses a variety of techniques from microscopy to spectroscopy. One such technique that is often used to identify the dye(s) within the fiber is mass spectrometry (MS). In the traditional MS method, the dye must be extracted from the fabric and the dye components are separated by chromatography prior to mass spectrometric analysis. Direct analysis of the dye from the fabric allows the omission of the lengthy sample preparation involved in extraction, ther...

  15. Comparison of 532 nm Potassium Titanyl Phosphate Laser and 595 nm Pulsed Dye Laser in the Treatment of Erythematous Surgical Scars: A Randomized, Controlled, Open-Label Study.

    Science.gov (United States)

    Keaney, Terrence C; Tanzi, Elizabeth; Alster, Tina

    2016-01-01

    The pulsed dye laser (PDL) has long been used for treatment of erythematous and hypertrophic scars. Its effectiveness has been attributed in large part to its vascular-specificity. The vascular-specific potassium titanyl phosphate (KTP) laser has also been reported to be clinically effective for scars, but has not been compared to the PDL. To compare the safety and clinical efficacy of a 532-nm KTP laser versus a 595-nm PDL in improving the appearance of erythematous surgical scars. Twenty patients with matched bilateral erythematous surgical scars or a single linear erythematous scar measuring longer than 5 cm were enrolled in the study. Single scars were divided into equal halves with each half randomized to receive 3 successive treatments at 6-week intervals with either a 532-nm KTP laser (Excel V; Brisbane, CA) or a 595-nm PDL (Cynergy; Cynosure Inc., Chelmsford, MA) at equivalent laser parameters. Bilateral matched scars were similarly randomized to receive three 532-nm KTP or 595-nm PDL treatments. Clinical efficacy was evaluated 12 weeks after the third (final) laser treatment by independent, blinded photographic scar assessments. Secondary evaluations included final investigator and subject treatment/satisfaction assessments, Vancouver scar scale (VSS) scores, subject scar symptoms, intraoperative pain scores, and incidence of side effects. Clinical improvement of erythematous surgical scars was observed with both 532-nm KTP and 595-nm PDL systems. No statistically significant differences between the 2 treatment arms were noted in the independent, blinded photographic scar assessments, investigator and subject treatment/satisfaction assessments, subject scar symptoms, and intraoperative pain scores. The KTP arm produced statistically significant improvement for the vascularity component of the VSS only. Side effects were limited to mild treatment discomfort and minimal transient post-treatment erythema and purpura. No vesiculation, infection, scarring or

  16. Two-rod high power pulsed Nd:YAG laser cutting system%一种双棒串接大功率固体激光切割系统

    Institute of Scientific and Technical Information of China (English)

    何琼; 杨晟; 范有雄; 王英

    2012-01-01

    A high power pulsed solid state laser cutting system.It is constituted by series-wound dual rods of 1000W lasers,CNC table,auto focus system and optic delivery system.And this system can fulfill multifarious metal cutting applications.Such as Carbon steel,S.steel,Al.,Brass in thickness of 1~8mm.Compare to single rod of 500W lasers and series-wound dual rods of 500W lasers,series-wound dual rods of 1000W lasers has advantages of faster cutting speed and cutting deeper.%介绍了一种以大功率脉冲固体激光器做为光源的激光切割系统,该系统主要由双棒串接1000W激光器、大幅面数控工作台、z轴随动系统、导光聚焦系统构成,该系统可满足1mm至8mm内的碳钢、不锈钢、铝、铜等金属材料的切割要求,可广泛应用于钣金切割行业。同时对比分析了单棒500W激光器、双棒串接500W激光器,双棒串接1000W激光器三种固体激光切割系统的特点,证明双棒串接1000W激光器具有更大的切割厚度和切割速度。

  17. Effectiveness of combined pulsed dye and Q-switched ruby laser treatment for large to giant congenital melanocytic naevi.

    Science.gov (United States)

    Funayama, E; Sasaki, S; Furukawa, H; Hayashi, T; Yamao, T; Takahashi, K; Yamamoto, Y; Oyama, A

    2012-11-01

    There is no consensus on the most appropriate treatment for patients with large to giant congenital melanocytic naevi (CMN) because of the risk of melanoma development. Surgical excision followed by skin grafting or expanded skin coverage may cause unfavourable scarring. There is a balance to be achieved between minimizing the disfiguring appearance and the risk of malignant change. The pulsed dye laser (PDL) is commonly used for vascular lesions and is highly absorbed by melanin and haemoglobin. Its pulse duration is longer than that of Q-switched ruby lasers (QsRL), which can have nonspecific photothermolytic effects on surrounding nonpigmented naevus cells. To investigate the effectiveness of combined treatment with the PDL and QsRL for large to giant CMN. Six patients with large to giant CMN were enrolled in this study. Treatment consisted of one pass of PDL treatment followed by one pass of QsRL treatment. Multiple rounds of treatment were applied to all patients. All patients responded to this combined regimen, and the lesional colour was effectively reduced. The mean number of rounds of laser treatment required to achieve skin lightening was 7·7. No patients suffered severe hypertrophic scarring. No cases of recurrence or malignant transformation were observed. The histological results from the patient who underwent the most laser therapy in this study showed a remarkable reduction in the number of melanocytic naevus cells after treatment. This technique may enable the removal of most of the pigmented lesion and melanocytic naevus cells with minimal scarring. © 2012 The Authors. BJD © 2012 British Association of Dermatologists.

  18. Properties of two-photon pumped cavity lasing in novel dye doped solid matrices

    Energy Technology Data Exchange (ETDEWEB)

    He, G.S.; Bhawalkar, J.D.; Zhao, C.; Prasad, P.N. [State Univ. of New York, Buffalo, NY (United States). Dept. of Chemistry

    1996-05-01

    Two-photon pumped frequency upconversion cavity lasing at {approximately}600 nm is accomplished in three types of dye-doped solid rods pumped with {approximately}10 ns and 1.06-{micro}m IR laser pulses. The dopant is a new dye, trans-4-[p-(N-ethyl-N-(hydroxyethyl)amino)styryl]-N-methylpyridinium tetraphenylborate, abbreviated as ASPT, which possesses a greater two-photon absorption cross section and stronger upconversion fluorescence emission than common commercial dyes (such as rhodamine). Three different materials were chosen as solid matrices: poly(2-hydroxyethyl methacrylate), VYCOR porous glass, and sol-gel glass. Using a Q-switched Nd:YAG pulse laser as the pump source, strong cavity lasing could be achieved in these three ASPT doped solid rods as well as in ASPT solution in a liquid cell. The spectral, temporal, and spatial characteristics of the cavity lasing output have been systematically investigated. The measured output-input characteristics, lasing lifetime, and damage threshold for the three different rods are presented.

  19. Near-infrared dye loaded polymeric nanoparticles for cancer imaging and therapy and cellular response after laser-induced heating

    Directory of Open Access Journals (Sweden)

    Tingjun Lei

    2014-03-01

    Full Text Available Background: In the past decade, researchers have focused on developing new biomaterials for cancer therapy that combine imaging and therapeutic agents. In our study, we use a new biocompatible and biodegradable polymer, termed poly(glycerol malate co-dodecanedioate (PGMD, for the synthesis of nanoparticles (NPs and loading of near-infrared (NIR dyes. IR820 was chosen for the purpose of imaging and hyperthermia (HT. HT is currently used in clinical trials for cancer therapy in combination with radiotherapy and chemotherapy. One of the potential problems of HT is that it can up-regulate hypoxia-inducible factor-1 (HIF-1 expression and enhance vascular endothelial growth factor (VEGF secretion.Results: We explored cellular response after rapid, short-term and low thermal dose laser-IR820-PGMD NPs (laser/NPs induced-heating, and compared it to slow, long-term and high thermal dose heating by a cell incubator. The expression levels of the reactive oxygen species (ROS, HIF-1 and VEGF following the two different modes of heating. The cytotoxicity of NPs after laser/NP HT resulted in higher cell killing compared to incubator HT. The ROS level was highly elevated under incubator HT, but remained at the baseline level under the laser/NP HT. Our results show that elevated ROS expression inside the cells could result in the promotion of HIF-1 expression after incubator induced-HT. The VEGF secretion was also significantly enhanced compared to laser/NP HT, possibly due to the promotion of HIF-1. In vitro cell imaging and in vivo healthy mice imaging showed that IR820-PGMD NPs can be used for optical imaging.Conclusion: IR820-PGMD NPs were developed and used for both imaging and therapy purposes. Rapid and short-term laser/NP HT, with a low thermal dose, does not up-regulate HIF-1 and VEGF expression, whereas slow and long term incubator HT, with a high thermal dose, enhances the expression of both transcription factors.

  20. Efficacy and safety of long-pulse pulsed dye laser delivered with compression versus cryotherapy for treatment of solar lentigines

    Directory of Open Access Journals (Sweden)

    Hassan Seirafi

    2011-01-01

    Full Text Available Background: Although cryotherapy is still the first-line therapy for solar lentigines, because of the side effects such as post-inflammatory hyperpigmentation (PIH, especially in patients with darker skin types, pigment-specific lasers should be considered as a therapy for initial treatment. Aim: The aim of this study is to evaluate the efficacy and safety of cryotherapy compared with 595-nm pulsed dye laser (PDL with cutaneous compression in the treatment of solar lentigines. Materials and Methods: Twenty-two patients (skin type II−IV with facial or hand lentigines participated in this study. Lesions of one side of the face or each hand were randomly assigned and treated with either cryotherapy or PDL. Treatments were performed with radiant exposures of 10 J/cm 2 , 7-mm spot size and 1.5 ms pulse duration with no epidermal cooling. Photographs were taken before treatment and 1-month later. The response rate and side effects were compared. Results: PDL was more likely to produce substantial lightening of the solar lentigines than cryotherapy, especially in skin type III and IV (n = 8, n = 9; P 0.05. PIH was seen only in cryotherapy group. PDL group had only minimal erythema. No purpura was observed. Conclusion: PDL with compression is superior to cryotherapy in the treatment of solar lentigines in darker skin types.

  1. Multimode distributed feedback laser emission in a dye-doped optically pumped polymer thin-film

    Science.gov (United States)

    Sobel, F.; Gindre, D.; Nunzi, J.-M.; Denis, C.; Dumarcher, V.; Fiorini-Debuisschert, C.; Kretsch, K. P.; Rocha, L.

    2004-11-01

    We report on particular features of thin film distributed feedback (DFB) lasers. Devices are optically pumped using a Lloyd-mirror interferometer. For a given DFB grating period, the number of lasing modes is film thickness dependent. Spectral content of the devices is analysed using planar waveguide theory. An excellent agreement between the theoretical transverse electric mode structure and the laser emission spectrum is found.

  2. Broadband optical absorption enhancement of N719 dye in ethanol by gold-silver alloy nanoparticles fabricated under laser ablation technique

    Science.gov (United States)

    Al-Azawi, Mohammed A.; Bidin, Noriah; Abbas, Khaldoon N.; Bououdina, Mohamed; Azzez, Shrook A.

    2016-04-01

    The formation of gold-silver alloy nanoparticles (Au-Ag alloy NPs) by a two-step process with a pulsed Nd:YAG laser without any additives is presented. Mixtures of Au and Ag colloidal suspensions were separately obtained by 1064-nm laser ablation of metallic targets immersed in ethanol. Subsequently, the as-mixed colloidal suspensions were reirradiated by laser-induced heating at the second-harmonic generation (532 nm) for different irradiation periods of time. The absorption spectra and morphology of the colloidal alloys were studied as a function of exposure time to laser irradiation. Transmission electron microscopy revealed the formation of monodispersed spherical nanoparticles with a homogeneous size distribution in all the synthesized samples. UV-vis and photoluminescence spectroscopy measurements were also employed to characterize the changes in the light absorption and emission of N719 dye solution with different concentrations of Au-Ag colloidal alloys, respectively. The localized surface plasmon resonance (LSPR) of Au-Ag alloy NPs enhanced the absorption and fluorescence peak of the dye solution. The mixture of dye molecules with a higher concentration of alloy NPs exhibited an additional coupling of dipole moments with the LSPR, thereby contributing to the improvement of the optical properties of the mixture.

  3. Synthesis and analysis of nickel dithiolene dyes in a nematic liquid crystal host. 1998 summer research program for high school juniors at the University of Rochester`s Laboratory for Laser Energetics: Student research reports

    Energy Technology Data Exchange (ETDEWEB)

    Lippa, I. [Byron-Bergen High School, NY (United States)

    1999-03-01

    The Liquid Crystal Point Diffraction Interferometer (LCPDI) can be employed to evaluate the Omega Laser system for optimum firing capabilities. This device utilizes a nickel dithiolene infrared absorbing liquid crystal dye dissolved in a liquid crystal host medium (Merck E7). Three nickel dithiolene dyes were characterized for both their solubility in the E7 host and their infrared spectral absorption.

  4. Development of excellent long-wavelength BODIPY laser dyes with a strategy that combines extending π-conjugation and tuning ICT effect.

    Science.gov (United States)

    Zhang, Dakui; Martín, Virginia; García-Moreno, Inmaculada; Costela, Angel; Pérez-Ojeda, M Eugenia; Xiao, Yi

    2011-07-28

    By comparison and combination of two strategies, extending π-conjugation and tuning Intramolecular Charge Transfer (ICT) effect, new long-wavelength BODIPY dyes have been efficiently synthesized. The new chromophores exhibit good optical properties: high fluorescence quantum yields, exceptionally large molar extinction coefficients, narrow red-emission bands, and relatively large Stokes shifts etc., in polar or apolar solvents. Besides, the new dyes, under transversal pumping at 532 nm, exhibit highly efficient and stable laser emission tunable from the green to NIR spectral region (570-725 nm). Moreover, one of these new BODIPY derivatives shows cell membrane permeability and bright intracellular red fluorescence. These advantageous characteristics assure the potential of these dyes for biophotonic applications.

  5. Effect of quencher and temperature on fluorescence intensity of laser dyes: DETC and C504T

    Science.gov (United States)

    Jana, Basavaraja; Inamdar, S. R.; Kumar, H. M. Suresh

    2017-01-01

    Fluorescence quenching of 7- Diethylamino-3-thenoylcoumarin (DETC) and 2,3,6,7-tetrahydro-1,1,7,7-tetramethyl11-oxo-1H,5H,11H- [1]benzopyrano[6,7,8-ij]quinolizine-10-carboxylic acid, ethyl ester (C504T) by aniline(AN), dimethylaniline (DMA) and diethylaniline (DEA) was investigated in toluene by steady state and transient methods. The quenching parameters like frequency of encounter (kd), probability of quenching per encounter (p), quenching rate parameters (kq) and activation energy of quenching (Ea) were determined experimentally. The kq values determined by steady state and time-resolved methods for the both dyes were found to be same, indicating the dynamic nature of interaction. Magnitudes of p and Ea suggested that the quenching reaction is predominantly controlled by material diffusion. The quenching mechanism is rationalized in terms of electron transfer (ET) from donors (aromatic amines) to the acceptors (coumarin derivatives) confirmed by correlating kq with free energy changes (ΔG°). Further, an effect of temperature on fluorescence intensity was carried out in toluene and methanol solvents. Fluorescence intensity of both the dyes decreases with increase in temperature. Temperature quenching in case of C504T is due to intersystem crossing S1 → T2, whereas for DETC, quenching is due to intersystem crossing S1 → T2 and ICT → TICT transition.

  6. Facile synthesis of silicon carbide-titanium dioxide semiconducting nanocomposite using pulsed laser ablation technique and its performance in photovoltaic dye sensitized solar cell and photocatalytic water purification

    Energy Technology Data Exchange (ETDEWEB)

    Gondal, M.A., E-mail: magondal@kfupm.edu.sa [Laser Research Group, Physics Department & Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Ilyas, A.M. [Laser Research Group, Physics Department & Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Baig, Umair [Laser Research Group, Physics Department & Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Center of Excellence for Scientific Research Collaboration with MIT, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2016-08-15

    Highlights: • SiC–TiO{sub 2} semiconducting nanocomposites synthesized by nanosecond PLAL technique. • Synthesized nanocomposites were morphologically and optically characterized. • Nanocomposites were applied for the photocatalytic degradation of toxic organic dye. • Photovoltaic performance was investigated in dye sensitized solar cell. - Abstract: Separation of photo-generated charge carriers (electron and holes) is a major approach to improve the photovoltaic and photocatalytic performance of metal oxide semiconductors. For harsh environment like high temperature applications, ceramic like silicon carbide is very prominent. In this work, 10%, 20% and 40% by weight of pre-oxidized silicon carbide was coupled with titanium dioxide (TiO{sub 2}) to form nanocomposite semiconductor via elegant pulsed laser ablation in liquid technique using second harmonic 532 nm wavelength of neodymium-doped yttrium aluminium garnet (Nd-YAG) laser. In addition, the effect of silicon carbide concentration on the performance of silicon carbide-titanium dioxide nanocomposite as photo-anode in dye sensitized solar cell and as photocatalyst in photodegradation of methyl orange dye in water was also studied. The result obtained shows that photo-conversion efficiency of the dye sensitized solar cell was improved from 0.6% to 1.65% and the percentage of methyl orange dye removed was enhanced from 22% to 77% at 24 min under ultraviolet–visible solar spectrum in the nanocomposite with 10% weight of silicon carbide. This remarkable performance enhancement could be due to the improvement in electron transfer phenomenon by the presence of silicon carbide on titanium dioxide.

  7. Facile synthesis of silicon carbide-titanium dioxide semiconducting nanocomposite using pulsed laser ablation technique and its performance in photovoltaic dye sensitized solar cell and photocatalytic water purification

    Science.gov (United States)

    Gondal, M. A.; Ilyas, A. M.; Baig, Umair

    2016-08-01

    Separation of photo-generated charge carriers (electron and holes) is a major approach to improve the photovoltaic and photocatalytic performance of metal oxide semiconductors. For harsh environment like high temperature applications, ceramic like silicon carbide is very prominent. In this work, 10%, 20% and 40% by weight of pre-oxidized silicon carbide was coupled with titanium dioxide (TiO2) to form nanocomposite semiconductor via elegant pulsed laser ablation in liquid technique using second harmonic 532 nm wavelength of neodymium-doped yttrium aluminium garnet (Nd-YAG) laser. In addition, the effect of silicon carbide concentration on the performance of silicon carbide-titanium dioxide nanocomposite as photo-anode in dye sensitized solar cell and as photocatalyst in photodegradation of methyl orange dye in water was also studied. The result obtained shows that photo-conversion efficiency of the dye sensitized solar cell was improved from 0.6% to 1.65% and the percentage of methyl orange dye removed was enhanced from 22% to 77% at 24 min under ultraviolet-visible solar spectrum in the nanocomposite with 10% weight of silicon carbide. This remarkable performance enhancement could be due to the improvement in electron transfer phenomenon by the presence of silicon carbide on titanium dioxide.

  8. Estimation of ground and excited state dipole moment of laser dyes C504T and C521T using solvatochromic shifts of absorption and fluorescence spectra.

    Science.gov (United States)

    Basavaraja, Jana; Kumar, H M Suresh; Inamdar, S R; Wari, M N

    2016-02-05

    The absorption and fluorescence spectra of laser dyes: coumarin 504T (C504T) and coumarin 521T (C521T) have been recorded at room temperature in a series of non-polar and polar solvents. The spectra of these dyes showed bathochromic shift with increasing in solvent polarity indicating the involvement of π→π⁎ transition. Kamlet-Taft and Catalan solvent parameters were used to analyze the effect of solvents on C504T and C521T molecules. The study reveals that both general solute-solvent interactions and specific interactions are operative in these two systems. The ground state dipole moment was estimated using Guggenheim's method and also by quantum mechanical calculations. The solvatochromic data were used to determine the excited state dipole moment (μ(e)). It is observed that dipole moment value of excited state (μ(e)) is higher than that of the ground state in both the laser dyes indicating that these dyes are more polar in nature in the excited state than in the ground state.

  9. Investigations on the growth, optical, thermal, dielectric, and laser damage threshold properties of crystal violet dye-doped potassium acid phthalate single crystal

    Science.gov (United States)

    Rao, G. Babu; Rajesh, P.; Ramasamy, P.

    2016-03-01

    Influence of crystal violet dye with different concentration on potassium acid phthalate single crystal grown by conventional method has been studied. No change has been observed in the structure, whereas changes have been observed in the external morphology of the crystal when the dyes are incorporated in the crystal lattice. Thermogravimetric and differential thermal analyses show the onset decomposition temperatures to be at 302, 285, 284, and 285 °C for pure, 0.1, 0.3, and 0.5 mol% crystal violet-doped potassium acid phthalate crystals, respectively. The dielectric measurement was carried out on the grown crystals as a function of frequency at various temperatures. In addition, strong luminescent emission bands at 638, 648, and 640 nm were observed in which the relative intensity was found to be reversed as a result of doping concentration. The laser damage threshold value significantly increased for dye-doped crystal in comparison with pure crystal which may make it suitable for the solid-state dye laser applications.

  10. Nanoimprinted distributed feedback dye laser sensor for real-time imaging of small molecule diffusion

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Dufva, Martin; Kristensen, Anders

    2014-01-01

    Label-free imaging is a promising tool for the study of biological processes such as cell adhesion and small molecule signaling processes. In order to image in two dimensions of space current solutions require motorized stages which results in low imaging frame rates. Here, a highly sensitive...... of different grating periods which result in distinct laser emission wavelengths. Imaging in two dimensions of space is enabled by focusing an image of the laser surface with a cylindrical lens onto the entrance slit of an imaging spectrometer. Imaging is demonstrated by monitoring of diffusing small sucrose...

  11. Organic Solid-State Tri-Wavelength Lasing from Holographic Polymer-Dispersed Liquid Crystal and a Distributed Feedback Laser with a Doped Laser Dye and a Semiconducting Polymer Film.

    Science.gov (United States)

    Liu, Minghuan; Liu, Yonggang; Peng, Zenghui; Wang, Shaoxin; Wang, Qidong; Mu, Quanquan; Cao, Zhaoliang; Xuan, Li

    2017-05-07

    Organic solid-state tri-wavelength lasing was demonstrated from dye-doped holographic polymer-dispersed liquid crystal (HPDLC) distributed feedback (DFB) laser with semiconducting polymer poly[-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene-vinylene] (MEH-PPV) and laser dye [4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran] (DCM) by a one-step holography technique, which centered at 605.5 nm, 611.9 nm, and 671.1 nm. The temperature-dependence tuning range for the tri-wavelength dye-doped HPDLC DFB laser was as high as 8 nm. The lasing emission from the 9th order HPDLC DFB laser with MEH-PPV as active medium was also investigated, which showed excellent s-polarization characterization. The diffraction order is 9th and 8th for the dual-wavelength lasing with DCM as the active medium. The results of this work provide a method for constructing the compact and cost-effective all solid-state smart laser systems, which may find application in scientific and applied research where multi-wavelength radiation is required.

  12. Pulsed dye laser does not seem as effective as red light in Basal cell carcinoma mal-pdt: a small pilot study.

    Science.gov (United States)

    Fernández-Guarino, M; Harto, A; Jaén, P

    2012-01-01

    Multiple light sources can be used for photodynamic therapy (PDT) with good results, but there are few comparative studies. This study compares the efficacy of treatment of basal cell carcinoma with PDT and two light sources, the non-coherent red light and pulsed dye laser 595 nm. In this small pilot study red light is more effective, but many more studies are needed to draw definitive conclusions.

  13. Pulsed Dye Laser Does Not Seem as Effective as Red Light in Basal Cell Carcinoma Mal-Pdt: A Small Pilot Study

    OpenAIRE

    Fernández-Guarino, M.; Harto, A.; Jaén, P.

    2012-01-01

    Multiple light sources can be used for photodynamic therapy (PDT) with good results, but there are few comparative studies. This study compares the efficacy of treatment of basal cell carcinoma with PDT and two light sources, the non-coherent red light and pulsed dye laser 595 nm. In this small pilot study red light is more effective, but many more studies are needed to draw definitive conclusions.

  14. Pulsed Dye Laser Does Not Seem as Effective as Red Light in Basal Cell Carcinoma Mal-Pdt: A Small Pilot Study

    Directory of Open Access Journals (Sweden)

    M. Fernández-Guarino

    2012-01-01

    Full Text Available Multiple light sources can be used for photodynamic therapy (PDT with good results, but there are few comparative studies. This study compares the efficacy of treatment of basal cell carcinoma with PDT and two light sources, the non-coherent red light and pulsed dye laser 595 nm. In this small pilot study red light is more effective, but many more studies are needed to draw definitive conclusions.

  15. Rapid preparation of rodent testicular cell suspensions and spermatogenic stages purification by flow cytometry using a novel blue-laser-excitable vital dye

    Directory of Open Access Journals (Sweden)

    Rosana Rodríguez-Casuriaga

    2014-01-01

    Inclusion of a non-cytotoxic, DNA-specific, 488 nm-excitable vital fluorochrome (Vybrant DyeCycle Green [VDG], Invitrogen instead of Hoechst 33342 (requires UV laser, which can damage nucleic acids or propidium iodide (usually related to dead/damaged cells. As far as we know, this is the first report on the use of this fluorochrome for the discrimination and purification of meiotic prophase I substages.

  16. Telangiectasis in CREST syndrome and systemic sclerosis: correlation of clinical and pathological features with response to pulsed dye laser treatment.

    Science.gov (United States)

    Halachmi, Shlomit; Gabari, Osama; Cohen, Sarit; Koren, Romelia; Amitai, Dan Ben; Lapidoth, Moshe

    2014-01-01

    Telangiectasia are cardinal features of systemic sclerosis (SS) and calcinosis, Raynaud's syndrome, esophageal motility, sclerodactyly, telangiectasias (CREST) syndrome. The etiology of telangiectasia in these syndromes is unknown, but vascular dysfunction has been proposed. However, the telangiectasia of CREST have anecdotally been considered relatively resistant to pulse dye laser (PDL), the treatment of choice for classic telangiectasia. The study was designed to test whether SS/CREST telangiectasia require more treatments than sporadic telangiectasia and to identify clinical and histological features that could explain such an effect. Nineteen skin biopsies from patients with SS or CREST and 10 control biopsies were examined and compared for features that may predict a differential response to PDL. Sixteen cases of SS or CREST treated with PDL between 1997 and 2007 were evaluated and response to treatment was compared with 20 patients with sporadic telangiectasis. Relative to normal skin, CREST/scleroderma telangiectasia exhibited thickened vessels in 17 out of 19 sections and thickened collagen fibers in the reticular or deep dermis in all sections. The number of treatments required to clear SS/CREST telangiectasia was approximately twofold higher. SS/CREST telangiectasia are more resistant to PDL but can be effectively cleared with more treatments.

  17. Safety and Efficacy Evaluation of Pulsed Dye Laser Treatment, CO2 Ablative Fractional Resurfacing, and Combined Treatment for Surgical Scar Clearance.

    Science.gov (United States)

    Cohen, Joel L; Geronemus, Roy

    2016-11-01

    Surgical scars are an unwanted sequela following surgical procedures. Several different treatment modalities and approaches are currently being employed to improve the cosmesis of surgical scars with each having varying degrees of success. The objective of this study was to assess the ef cacy and safety pulsed dye laser treatment, CO2 ablative fractional resurfacing, and a combined treatment with these two modalities for the cosmetic improvement of surgical scarring that occurred following the surgical removal of skin cancer from different anatomic areas. Twenty-five patients with surgical scarring most frequently on the face following recent surgical excision of skin cancer with Mohs surgery were included in this multicenter, prospective clinical study. Patients were randomized into 4 treatment arms, namely, pulsed dye laser alone, CO2 laser alone, a combined treatment with these two modalities, and CO2 ablative fractional resurfacing on the same day of surgery to half of the scar, followed by a combined treatment with the two modalities to that half of the scar. Patients in each study arm received a total of 3-4 treatments, while those patients in Arm 4 underwent an additional treatment with CO2 laser immediately after surgery. Patients were followed up at 1 and 3 months after the final treatment session. No adverse events were seen. Significant improvements in the appearance of scars were achieved in all study arms, as as- sessed by the Vancouver Scar Scale and Global Evaluation Response scales, with the best clinical outcomes seen in those scars that underwent a combination treatment. All patients reported very high satisfaction from treatment. Both pulsed dye laser treatment and CO2 ablative fractional resurfacing, when used as a monotherapy, are safe and effective in the treatment and improvement of recent surgical scarring. When both of these modalities are used in combination, however, they appear to potentially have a synergistic effect and an accelerated

  18. Understanding and controlling laser-matter interactions: From solvated dye molecules to polyatomic molecules in gas phase

    Science.gov (United States)

    Konar, Arkaprabha

    The goal of my research is to obtain a better understanding of the various processes that occur during and following laser-matter interactions from both the physical and chemical point of view. In particular I focused my research on understanding two very important aspects of laser-matter interaction; 1) Intense laser-matter interactions for polyatomic molecules in the gas phase in order to determine to what extent processes like excitation, ionization and fragmentation can be controlled by modifying the phase and amplitude of the laser field according to the timescales for electronic, vibrational and rotational energy transfer. 2) Developing pulse shaping based single beam methods aimed at studying solvated molecules in order to elucidate processes like inhomogeneous broadening, solvatochromic shift and to determine the electronic coherence lifetimes of solvated molecules. The effect of the chirped femtosecond pulses on fluorescence and stimulated emission from solvated dye molecules was studied and it was observed that the overall effect depends quadratically on pulse energy, even where excitation probabilities range from 0.02 to 5%, in the so-called "linear excitation regime". The shape of the chirp dependence is found to be independent of the energy of the pulse. It was found that the chirp dependence reveals dynamics related to solvent rearrangement following excitation and also depends on electronic relaxation of the chromophore. Furthermore, the chirped pulses were found to be extremely sensitive to solvent environment and that the complementary phases having the opposite sign provide information about the electronic coherence lifetimes. Similar to chirped pulses, the effects of a phase step on the excitation spectrum and the corresponding changes to the stimulated emission spectrum were also studied and it was found that the coherent feature on the spectrum is sensitive to the dephasing time of the system. Therefore a single phase scanning method can

  19. Pulsed laser deposited porous nano-carpets of indium tin oxide and their use as charge collectors in core-shell structures for dye sensitized solar cells.

    Science.gov (United States)

    Garvey, Timothy R; Farnum, Byron H; Lopez, Rene

    2015-02-14

    Porous In2O3:Sn (ITO) films resembling from brush carpets to open moss-like discrete nanostructures were grown by pulsed laser deposition under low to high background gas pressures, respectively. The charge transport properties of these mesoporous substrates were probed by pulsed laser photo-current and -voltage transient measurements in N719 dye sensitized devices. Although the cyclic voltammetry and dye adsorption measurements suggest a lower proportion of electro-active dye molecules for films deposited at the high-end background gas pressures, the transient measurements indicate similar electron transport rates within the films. Solar cell operation was achieved by the deposition of a conformal TiO2 shell layer by atomic layer deposition (ALD). Much of the device improvement was shown to be due to the TiO2 shell blocking the recombination of photoelectrons with the electrolyte as recombination lifetimes increased drastically from a few seconds in uncoated ITO to over 50 minutes in the ITO with a TiO2 shell layer. Additionally, an order of magnitude increase in the electron transport rate in ITO/TiO2 (core/shell) films was observed, giving the core-shell structure a superior ratio of recombination/transport times.

  20. Comparison of TiO₂ and ZnO solar cells sensitized with an indoline dye: time-resolved laser spectroscopy studies of partial charge separation processes.

    Science.gov (United States)

    Sobuś, Jan; Burdziński, Gotard; Karolczak, Jerzy; Idígoras, Jesús; Anta, Juan A; Ziółek, Marcin

    2014-03-11

    Time-resolved laser spectroscopy techniques in the time range from femtoseconds to seconds were applied to investigate the charge separation processes in complete dye-sensitized solar cells (DSC) made with iodide/iodine liquid electrolyte and indoline dye D149 interacting with TiO2 or ZnO nanoparticles. The aim of the studies was to explain the differences in the photocurrents of the cells (3-4 times higher for TiO2 than for ZnO ones). Electrochemical impedance spectroscopy and nanosecond flash photolysis studies revealed that the better performance of TiO2 samples is not due to the charge collection and dye regeneration processes. Femtosecond transient absorption results indicated that after first 100 ps the number of photoinduced electrons in the semiconductor is 3 times higher for TiO2 than for ZnO solar cells. Picosecond emission studies showed that the lifetime of the D149 excited state is about 3 times longer for ZnO than for TiO2 samples. Therefore, the results indicate that lower performance of ZnO solar cells is likely due to slower electron injection. The studies show how to correlate the laser spectroscopy methodology with global parameters of the solar cells and should help in better understanding of the behavior of alternative materials for porous electrodes for DSC and related devices.

  1. HF-based clad etching of fibre Bragg grating and its utilization in concentration sensing of laser dye in dye–ethanol solution

    Indian Academy of Sciences (India)

    J Kumar; R Mahakud; O Prakash; S K Dixit

    2014-02-01

    This paper presents a fiber Bragg grating (FBG) based sensor to study the concentration of laser dye in dye–ethanol solution. The FBG used in this experiment is indigenously developed using 255 nm UV radiations from copper vapour laser. The cladding of the FBG was partially removed using HF-based etching to make FBG sensitive to changes in the surrounding refractive index. The experimental results on the shift of the Bragg peak wavelength with HF etching and different dye concentration in ethanol are presented. The Bragg wavelength shifted from 1534.670 nm to 1534.225 nm in 30 min and from this point to 1533.97 in the next 2 min. The clad-etched Bragg peak shifted almost linearly from 1534.056 nm to 1534.162 nm as surrounding dye concentration in ethanol changes from 0 mM to 1.5 mM. It was observed that sensitivity depends on the concentration of the solution and found to be 70 pm/mM.

  2. Medium performance effect on the high output energy from a xenon lamp-pumped pyrromethene-567 solid-state dye laser

    Institute of Scientific and Technical Information of China (English)

    Wang Lei; Chen De-Ying; Fan Rong-Wei; He Wei-Ming

    2012-01-01

    In order to obtain a high output energy from a xenon lamp-pumped solid-state dye laser,homogeneities of laser mediums and flatnesses of medium faces with different processing treatments are discussed in the paper.The mediums without aging treatment,which are prepared by using a prepolymer process and have diamond-machined end faces to produce the required optical finish,give a highest laser output of 281.9 mJ with 0.215% slope efficiency at 2.0×10-4 mol/L.The best medium lifetime is 21 shots to 50% of original output equating 74.6 kJ/liter.

  3. Re-evaluation of all-plastic organic dye laser with DFB structure fabricated using photoresists

    Science.gov (United States)

    Tsutsumi, Naoto; Nagi, Saori; Kinashi, Kenji; Sakai, Wataru

    2016-10-01

    Organic solid-state lasers (OSSLs) with distributed feedback structures can detect nanoscale materials and therefore offer an attractive sensing platform for biological and medical applications. Here we investigate the lasing characteristics, i.e., the threshold and slope efficiency, as a function of the grating depth in OSSL devices with distributed feedback (DFB) structure fabricated using photoresists. Two types of photoresists were used for the DFB structures: a negative photoresist, SU-8 2002, and a positive photoresist, ma-P 1275. The DFB structure was fabricated using a Lloyd-mirror configuration. The active layer was a rhodamine 6G-doped cellulose acetate waveguide. The threshold for the first order mode (m  = 1) was lower than that for the second and third order modes (m = 2, and 3). A low threshold of 27 μJ cm-2 pulse-1 (58 nJ) was obtained using SU-8 2002, with m = 1. The slope efficiency was evaluated as a function of grating depth for each mode and increased as the grating depth increased.

  4. Tie rod insertion test

    CERN Multimedia

    B. LEVESY

    2002-01-01

    The superconducting coil is inserted in the outer vaccum tank and supported by a set of tie rods. These tie rods are made of titanium alloy. This test reproduce the final insertion of the tie rods inside the outer vacuum tank.

  5. Comparison of fractional, nonablative, 1550-nm laser and 595-nm pulsed dye laser for the treatment of facial erythema resulting from acne: a split-face, evaluator-blinded, randomized pilot study.

    Science.gov (United States)

    Park, Kui Young; Ko, Eun Jung; Seo, Seong Jun; Hong, Chang Kwun

    2014-06-01

    Postinflammatory erythema is commonly seen in patients with inflammatory acne. There are no reliable treatment guidelines for acne erythema. We compared the effect and safety of a nonablative, 1550-nm fractional laser and a 595-nm pulsed dye laser (PDL) for the treatment of acne erythema. Twelve Korean patients with acne erythema were enrolled. Sides of the face were randomized to receive treatment with a fractional laser or a PDL for a total of three treatments at 4-week intervals. The assessment of effectiveness was mean change in mexameter scores, investigator's and patients' clinical assessments. Statistically significant improvements in baseline acne erythema were observed through an improved erythema index on both treated sides. But, the improvements from each laser treatment were not significantly different. Mean scores of investigator assessments were 3.42 ± 0.67 in fractional laser-treated sites and 3.33 ± 0.65 in PDL-treated sites. Patients assessed their improvement as good or excellent in 91.7% of fractional laser-treated sites and 75% of PDL-treated sites. Both lasers are effective and safe modalities for the treatment of acne erythema; however, these data suggest better clinical efficacy with the use of a 1550-nm, erbium-glass fractional laser.

  6. Superficial hemangioma is better treated by topical 5-aminolevulinic followed by 595-nm pulsed dye laser therapy rather than 595-nm laser therapy alone.

    Science.gov (United States)

    Zeng, Ming; Shen, Songke; Chen, Wei; Yang, Chunjun; Liu, ShengXiu

    2017-08-16

    The aim of this study was to compare the efficacy and adverse effects of a 595-nm pulsed dye laser therapy alone (PDL alone) with a 5-aminolevulinic (5-ALA) local application followed by a 595-nm PDL (5-ALA PDL) in the treatment of superficial hemangioma (SH). A prospectively randomized study in 181 patients with SH was carried out over a period of 24 months. One hundred and ninety-three patients were seen. One hundred and eighty-one patients with SH were enrolled, of which 165 completed final follow-up. One hundred and nineteen patients received PDL alone and 46 received 5-ALA PDL. The patients were assessed clinically and the patient's parents were given a satisfaction questionnaire. Baseline patient data (gender, lesion size, lesion site, treatment times, cure rate, and adverse reactions) were recorded and the results of the treatment of the two groups were analyzed and compared. Complete clearing of the lesion (recovery grade 4) was achieved in 44/119 (37.0%) of the PDL alone group and 31/46 (67.4%) of the 5-ALA PDL group (X (2) = 10.30, p < 0.001). Atrophic scars, hyper- and hypopigmentation occurred in both groups (X (2) = 3.32, p = 0.564). The patients' parents' satisfaction was greater in the 5-ALA PDL group. The clinical outcome of 5-ALA PDL was superior to that of PDL alone in the treatment of SH and only minor adverse events occurred in each group.

  7. Single mode solid state distributed feedback dye laser fabricated by grey scale electron beam lithography on dye doped SU-8 resist

    DEFF Research Database (Denmark)

    Balslev, Søren; Rasmussen, Torben; Shi, Peixiong

    2005-01-01

    are optically pumped at 532 nm, and exhibit low lasing threshold from 530 nJ/mm2 and single mode output at selectable wavelengths from 580 to 630 nm, determined by the grating pitch. The lasers are well suited for integration into polymer based lab-on-chip circuits for interference based sensing....

  8. Long-pulsed dye laser versus intense pulsed light for photodamaged skin: A randomized split-face trial with blinded response evaluation

    DEFF Research Database (Denmark)

    Jorgensen, G.F.; Hedelund, L.; Haedersdal, M.

    2008-01-01

    Objective: In a randomized controlled split-face trial to evaluate efficacy and adverse effects from rejuvenation with long-pulsed dye laser (LPDL) versus intense pulsed light (IPL). Materials and Methods: Twenty female volunteers with Fitzpatrick skin types I-III, classes I-II rhytids, and symme......Objective: In a randomized controlled split-face trial to evaluate efficacy and adverse effects from rejuvenation with long-pulsed dye laser (LPDL) versus intense pulsed light (IPL). Materials and Methods: Twenty female volunteers with Fitzpatrick skin types I-III, classes I-II rhytids...... assigned to left and right sides. Primary end-points were telangiectasias, irregular pigmentation and preferred treatment. Secondary end-points were skin texture, rhytids, pain, and adverse effects. Efficacy was evaluated by patient self-assessments and by blinded clinical on-site and photographic.......031, 3, 6 months). Irregular pigmentation and skin texture improved from both treatments with no significant side-to-side differences. No reduction was seen of rhytides on LPDL- or IPL-treated sides. Treatment-related pain scores were significantly higher after IPL (medians 7-8) than LPDL (4...

  9. Determination of Metals Present in Textile Dyes Using Laser-Induced Breakdown Spectroscopy and Cross-Validation Using Inductively Coupled Plasma/Atomic Emission Spectroscopy

    Directory of Open Access Journals (Sweden)

    K. Rehan

    2017-01-01

    Full Text Available Laser-induced breakdown spectroscopy (LIBS was used for the quantitative analysis of elements present in textile dyes at ambient pressure via the fundamental mode (1064 nm of a Nd:YAG pulsed laser. Three samples were collected for this purpose. Spectra of textile dyes were acquired using an HR spectrometer (LIBS2000+, Ocean Optics, Inc. having an optical resolution of 0.06 nm in the spectral range of 200 to 720 nm. Toxic metals like Cr, Cu, Fe, Ni, and Zn along with other elements like Al, Mg, Ca, and Na were revealed to exist in the samples. The %-age concentrations of the detected elements were measured by means of standard calibration curve method, intensities of every emission from every species, and calibration-free (CF LIBS approach. Only Sample 3 was found to contain heavy metals like Cr, Cu, and Ni above the prescribed limit. The results using LIBS were found to be in good agreement when compared to outcomes of inductively coupled plasma/atomic emission spectroscopy (ICP/AES.

  10. 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,

  11. Telescopic drilling rod

    Energy Technology Data Exchange (ETDEWEB)

    Kagan, I.L.; Berezov, S.I.; Gavrilov, G.A.; Goykhman, Ya.A.; Makushkin, D.O.; Rachev, M.P.; Voynich, L.K.

    1981-09-07

    The telescopic drilling rod includes an inner section of the rod, in whose center cable has been passed and is attached a bearing assembly connecting it to the winch, outer section of rod along which there is pipeline connecting the working cavity formed by the inner section of rod and the housing, installed on the lower end of the outer section of rod, with cavity formed by framework of the guide swivel and end piece and connected to the hydraulic system of the machine by pipeline, as well as clamping elements. In order to drill wells to a depth greater than the length of the outer sectrion of the rod, the latter jointly with the inner section of rod is lowered into the extreme lower position until swivel rests on the feed mechanism. With further slipping of cable and the absence of pressure in the hydraulic system, clamping elements do not have an effect on the inner section of rod. It has the opportunity to freely move along the outer section of rod downwards to the face. When pressure is supplied on pipeline into cavity and further through pipeline into working cavity, the inner section of rod is clamped with feed of the outer section in the process of drilling, both sections move jointly. Because of the link between working cavity of sleeve installed on the lower end of the outer section of rod, and the hydraulic system of the machine through the swivel cavity, it is possible to fix the drilling rod in any mutual axial position of the section.

  12. Relation between skin surface temperature and minimal blanching during argon, Nd-YAG 532, and CW dye 585 laser therapy of port-wine stains.

    Science.gov (United States)

    Mordon, S; Beacco, C; Rotteleur, G; Brunetaud, J M

    1993-01-01

    Laser photocoagulation has proven to be valuable in the treatment of port-wine stains. In this application, the minimal blanching technique is used as an indicator of suitable dosage since it has been demonstrated that the immediate appearance a white mark is required to achieve permanent blanching a few months later. The objective of the investigations undertaken in this study was to correlate the temperature attained at the surface of port-wine stains with immediate blanching, upon irradiation with different laser fluences. A comparative study was performed using an argon laser (all lines), a 532 nm Nd:YAG and a 585 nm argon pumped dye laser. Surface temperature was studied using an infrared camera. Temperature was measured on 10 different port-wine stains using different fluences. Whitening threshold fluence was related to surface temperature. It appeared that whitening threshold fluence corresponded to a surface temperature of 53 degrees C (+/- 3 degrees C). The whitening threshold fluence was dependent on port-wine stains and wavelength. However, whitening threshold fluence remained lower for 532 nm and 585 nm and it correlated to the absorption curve of hemoglobin.

  13. Rapid sintering of MoS2 counter electrode using near-infrared pulsed laser for use in highly efficient dye-sensitized solar cells

    Science.gov (United States)

    Jeong, Hansol; Kim, Jae-Yup; Koo, Bonkee; Son, Hae Jung; Kim, Dongwhan; Ko, Min Jae

    2016-10-01

    Molybdenum disulfide (MoS2) is a promising material for use as a low-cost electrocatalytic counter electrode (CE) in photoelectrochemical dye-sensitized solar cells (DSSCs). However, currently, the MoS2 CEs are generally prepared with a high temperature sintering for the synthesis and crystallization of MoS2. Here, we report a simple and rapid method for the preparation of highly efficient MoS2 CEs. The MoS2 films were synthesized at 70 °C, followed by sintering with a near-infrared (IR) pulsed laser for 1 min. Compared to the conventional heat-sintered MoS2 CE, the laser-sintered CE showed enhanced crystallinity and improved interconnection between the MoS2 particles, resulting in superior electrocatalytic activity towards the I-/I3- redox couple. When used in a DSSC, the laser-sintered MoS2 CE exhibited a higher conversion efficiency (η = 7.19%) compared to that of the heat-sintered CE (η = 5.96%). Furthermore, the laser-sintered CE had a comparable conversion efficiency compared to that of the conventional Pt CE (η = 7.42%).

  14. Photodissociation Dye Laser

    Science.gov (United States)

    1976-04-01

    Field Bedford, MA 01730 Attn: Mr. Alfred E, Anderson (XRT) Capt. James C. jalbert (XRJ) Technical Library Air Force Rocket Propulsion Lab...Corp. Chirley Highway at Edsall Rd. Alexandria, VA 22314 Attn: Mr. Robert Naismith AVCO Fiverett Res. Lab. ,,38’i Rrverp Beach Farlo^ay

  15. High Power Dye Lasers

    Science.gov (United States)

    1975-09-30

    art capabilities for developmental models of hydrogen thyratrons and solid state thyristors. Table II-l is a list of switches that have been... thyratron Table II-l Switch Ignitron GE, GL - 37207 Hydrogen Thyratron High Power Switches Peak Cur. (kA) RMS Cm. (A) 300 120 Max. Rep Rate...for 2 usec Pulse Cli„) 8 1. EG&G HY-5 2. EW. GHT9 3. EG&G Develop- mental model Thyristors 5 7.5 15 125 335 350 300 1000 300 RCA

  16. Photodissociation Dye Laser

    Science.gov (United States)

    1975-04-01

    synthesis routes and experimental technique usec ip the preparation o£ these compounds are given In Appendix I. It sltouid be pointed out that these...Candidates In the following pages, we have diagrammed, and outlined the reported synthesis routes from commercially available starting materials which we...solution of spiro-(fluorene-9.3,- indazole ) (10.0 g, 37.3 mmole, 10), in 80 ml. of decalin was slowly heated to reflux (186 ) employing a magnetic

  17. [Tattooing dyes].

    Science.gov (United States)

    Lehmann, G; Pierchalla, P

    1988-01-01

    Nine different tattoo dyes were analysed by various tests. Mixtures of organic dyes and inorganic filler were found; the inorganic filler consisted mainly of titanium dioxide (TiO2). Heavy metals, e.g. mercury, cadmium, or chrome as the common components of the traditional tattoo dyes, are capable of evoking unwanted skin reactions, but were not detected. Tattoo dyes are not officially controlled, and thus it is not known which substances-in addition to those identified by us-are presently used to produce ornamental tattoos. However, our results suggest that classic dyes have been superceded by newer, mainly synthetic dyes.

  18. Photon-Echo Relaxation Measurements with Two Dye-Lasers. Application to Pentacene-h14 and -d14 in p-Terphenyl-h14 Crystals at 1.5 K

    NARCIS (Netherlands)

    Morsink, Jos B.W.; Aartsma, Thijs J.; Wiersma, Douwe A.

    1977-01-01

    Electronically controlled photon-echo relaxation measurements, using two nitrogen pumped dye-lasers, are reported for mixed crystals of pentacene-h14 and -d14 in p-terphenyl-h14 at 1.5 K. In dilute mixed crystals (ca. 10-8 M) the photon-echo lifetime is found to be exclusively determined by the fluo

  19. A highly efficient and compact long pulse Nd:YAG rod laser with 540 J of pulse energy for welding application.

    Science.gov (United States)

    Choubey, Ambar; Vishwakarma, S C; Misra, Pushkar; Jain, R K; Agrawal, D K; Arya, R; Upadhyaya, B N; Oak, S M

    2013-07-01

    We have developed an efficient and high average power flash lamp pumped long pulse Nd:YAG laser capable of generating 1 kW of average output power with maximum 540 J of single pulse energy and 20 kW of peak power. The laser pulse duration can be varied from 1 to 40 ms and repetition rate from 1 to 100 Hz. A compact and robust laser pump chamber and resonator was designed to achieve this high average and peak power. It was found that this laser system provides highest single pulse energy as compared to other long pulsed Nd:YAG laser systems of similar rating. A slope efficiency of 5.4% has been achieved, which is on higher side for typical lamp pumped solid-state lasers. This system will be highly useful in laser welding of materials such as aluminium and titanium. We have achieved 4 mm deep penetration welding of these metals under optimized conditions of output power, pulse energy, and pulse duration. The laser resonator was optimized to provide stable operation from single shot to 100 Hz of repetition rate. The beam quality factor was measured to be M(2) ~ 91 and pulse-to-pulse stability of ±3% for the multimode operation. The laser beam was efficiently coupled through an optical fiber of 600 μm core diameter and 0.22 numerical aperture with power transmission of 90%.

  20. A highly efficient and compact long pulse Nd:YAG rod laser with 540 J of pulse energy for welding application

    Science.gov (United States)

    Choubey, Ambar; Vishwakarma, S. C.; Misra, Pushkar; Jain, R. K.; Agrawal, D. K.; Arya, R.; Upadhyaya, B. N.; Oak, S. M.

    2013-07-01

    We have developed an efficient and high average power flash lamp pumped long pulse Nd:YAG laser capable of generating 1 kW of average output power with maximum 540 J of single pulse energy and 20 kW of peak power. The laser pulse duration can be varied from 1 to 40 ms and repetition rate from 1 to 100 Hz. A compact and robust laser pump chamber and resonator was designed to achieve this high average and peak power. It was found that this laser system provides highest single pulse energy as compared to other long pulsed Nd:YAG laser systems of similar rating. A slope efficiency of 5.4% has been achieved, which is on higher side for typical lamp pumped solid-state lasers. This system will be highly useful in laser welding of materials such as aluminium and titanium. We have achieved 4 mm deep penetration welding of these metals under optimized conditions of output power, pulse energy, and pulse duration. The laser resonator was optimized to provide stable operation from single shot to 100 Hz of repetition rate. The beam quality factor was measured to be M2 ˜ 91 and pulse-to-pulse stability of ±3% for the multimode operation. The laser beam was efficiently coupled through an optical fiber of 600 μm core diameter and 0.22 numerical aperture with power transmission of 90%.

  1. Dye Painting!

    Science.gov (United States)

    Johnston, Ann

    This resource provides practical instructions for applying color and design directly to fabric. Basic information about the dye painting process is given. The guide addresses the technical aspects of fabric dye and color use and offers suggestions for fabric manipulation and dye application in order to achieve various design effects. This…

  2. Dye Painting!

    Science.gov (United States)

    Johnston, Ann

    This resource provides practical instructions for applying color and design directly to fabric. Basic information about the dye painting process is given. The guide addresses the technical aspects of fabric dye and color use and offers suggestions for fabric manipulation and dye application in order to achieve various design effects. This…

  3. Pulsed Dye Laser Treatment in Infantile Hemangioma%婴幼儿血管瘤的脉冲染料激光治疗

    Institute of Scientific and Technical Information of China (English)

    吕东泽(综述); 马刚; 林晓曦(审校)

    2014-01-01

    [Summary] Infantile hemangioma (IH) is the most common benign tumor of infancy. Although it is self-limiting, its cosmetic problems and complications still has been the psychological concerns of the patients and parents. Pulsed dye laser (PDL) is the criterion standard for treating vascular lesions. It is controversial in treating IH, despite the 20 years' application. In this article, the current knowledge of the PDL treatment of IH was reviewed comprehensively and the new implications and directions for management of IH in the future were provided.%婴幼儿血管瘤(Infantile hemangioma,IH)是最常见的婴幼儿良性肿瘤,虽为自限性疾病,但其外观及并发症影响患儿的身心发育,成为家长的心理负担。脉冲染料激光(Pulse dye laser,PDL)是用于血管性病灶的规范化激光,用于治疗浅表婴幼儿血管瘤已有20余年,但仍存在争议。本文综合阐述PDL治疗IH的研究进展,为IH的治疗提供方向。

  4. Nd:YAG and pulsed dye laser therapy in infantile haemangiomas: a retrospective analysis of 271 treated haemangiomas in 149 children.

    Science.gov (United States)

    Hartmann, F; Lockmann, A; Grönemeyer, L-L; Haenssle, H A; Zutt, M; von Fintel, H; Kühnle, I; Schön, M P; Thoms, K-M

    2017-08-01

    Infantile haemangiomas (IH) are common benign tumours in infancy. Most IH resolve spontaneously, but some require treatment due to ulceration, functional impairment or cosmetic disfiguration. While systemic propranolol is effective in many cases, laser therapy may be a safe topical alternative. To assess the efficacy of combined Nd:YAG/pulsed dye laser (PDL) or PDL alone for therapy of IH. A total of 271 IH in 149 infants were treated with combined Nd:YAG/PDL or PDL alone. Based on photographs before and 4-6 weeks after the last treatment, the results were evaluated independently by three physicians. Remissions were categorized as 0-25% (I), 26-50% (II), 51-75% (III) and 76-100% (IV). In total, 472 laser treatments were performed. In 137 of 149 infants (91.9%) laser therapy was performed during a short sevoflurane mask anaesthesia, while 12 of 149 infants (8.1%) received topical anaesthetic gel. Combined Nd:YAG/PDL was applied in 187 of 271 IH (69.0%), while PDL alone in 84 of 271 IH (31.0%). On average, 1.74 treatments per IH were necessary (Nd:YAG/PDL: 1.95, PDL: 1.26). Moderate or strong (III/IV) improvement was observed in 92.4% of all IH treated. No serious adverse effects were observed. Combined Nd:YAG/PDL therapy is an effective and well-tolerated local treatment option for IH of any classification, in any phase of development and at any age. With regard to the systemic use of propranolol, combined Nd:YAG/PDL therapy seems a safe and promising alternative in many cases. © 2016 European Academy of Dermatology and Venereology.

  5. Improvement of light harvesting and device performance of dye-sensitized solar cells using rod-like nanocrystal TiO{sub 2} overlay coating on TiO{sub 2} nanoparticle working electrode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xueyang; Fang, Jian [Institute for Frontier Materials, Deakin University, VIC 3220 (Australia); Gao, Mei [CSIRO Materials Science and Engineering, Melbourne, VIC 3169 (Australia); Wang, Hongxia [Institute for Frontier Materials, Deakin University, VIC 3220 (Australia); Yang, Weidong [CSIRO Materials Science and Engineering, Melbourne, VIC 3169 (Australia); Lin, Tong, E-mail: tong.lin@deakin.edu.au [Institute for Frontier Materials, Deakin University, VIC 3220 (Australia)

    2015-02-01

    Novel TiO{sub 2} single crystalline nanorods were synthesized by electrospinning and hydrothermal treatment. The role of the TiO{sub 2} nanorods on TiO{sub 2} nanoparticle electrode in improvement of light harvesting and photovoltaic properties of dye-sensitized solar cells (DSSCs) was examined. Although the TiO{sub 2} nanorods had lower dye loading than TiO{sub 2} nanoparticle, they showed higher light utilization behaviour. Electron transfer in TiO{sub 2} nanorods received less resistance than that in TiO{sub 2} nanoparticle aggregation. By just applying a thin layer of TiO{sub 2} nanorods on TiO{sub 2} nanoparticle working electrode, the DSSC device light harvesting ability and energy conversion efficiency were improved significantly. The thickness of the nanorod layer in the working electrode played an important role in determining the photovoltaic property of DSSCs. An energy conversion efficiency as high as 6.6% was found on a DSSC device with the working electrode consisting of a 12 μm think TiO{sub 2} nanoparticle layer covered with 3 μm thick TiO{sub 2} nanorods. The results obtained from this study may benefit further design of highly efficient DSSCs. - Highlights: • Single crystalline TiO{sub 2} nanorods were prepared for DSSC application. • TiO{sub 2} nanorods show effective light scattering performance. • TiO{sub 2} nanorods have higher electron transfer efficiency than TiO{sub 2} nanoparticles. • TiO{sub 2} nanorods on TiO{sub 2} nanoparticle electrode improve DSSC efficiency.

  6. Loading effect of Ag/AgO on the photocatalytic performance of ZnO rods

    Science.gov (United States)

    Samsuddin, Aida Fitri; Aziz, Siti Nor Qurratu Aini Abd; Pung, Swee-Yong

    2017-01-01

    The photocatalytic performance of ZnO rods in degradation of Rhodamine B dye under UV light was improved by 7.3% via deposition of Ag/AgO using 1.0 × 10-3 g mL-1 of silver nitrate solution. However, its photodegradation efficiency decreased with the increase in silver nitrate concentration which was used to prepare the Ag/AgO-ZnO rods. This result suggests that the loading of Ag/AgO on the surface of ZnO rods affected the photocatalytic performance differently. The scavenger study indicates that the main reactive species responsible for the degradation of Rhodamine B dye by Ag-/AgO-deposited ZnO rods were holes, followed by superoxide anion free radicals, hydroxyl free radicals and electrons. Based on these findings, a refined photodegradation mechanism of Rhodamine B by Ag/AgO-ZnO rods is proposed.

  7. Single Rod Vibration in Axial Flow

    Science.gov (United States)

    Weichselbaum, Noah; Wang, Shengfu; Bardet, Philippe

    2013-11-01

    Fluid structure interaction of a single rod in axial flow is a coupled dynamical system present in many application including nuclear reactors, steam generators, and towed antenna arrays. Fluid-structure response can be quantified thanks to detailed experimental data where both structure and fluid responses are recorded. Such datum deepen understanding of the physics inherent to the system and provide high-dimensionality quantitative measurements to validate coupled structural and CFD codes with various level of complexity. In this work, single rods fixed on both ends in a concentric pipe, are subjected to an axial flow with Reynolds number based on hydraulic diameter of Re =4000. Rods of varying material stiffness and diameter are utilized in the experiment resulting in a range of dimensionless U between 0.5 and 1, where U = (ρA/EI)1/2uL. Experimental measurements of the velocity field around the rod are taken with PIV from time-resolved Nd:YLF laser and a high speed CMOS camera. Three-dimensional and temporal vibration and deflection of the rod is recorded with shadowgraphy utilizing two sets of pulsed high power LED and dedicated CMOS camera. Through integration of these two diagnostics, it is possible to reconstruct the full FSI domain providing unique validation data.

  8. Prospective Comparison of Dual Wavelength Long-Pulsed 755-nm Alexandrite/1,064-nm Neodymium:Yttrium-Aluminum-Garnet Laser versus 585-nm Pulsed Dye Laser Treatment for Rosacea

    Science.gov (United States)

    Seo, Hyun-Min; Kim, Jung-In; Kim, Han-Saem; Choi, Young-Jun

    2016-01-01

    Background Rosacea treatments including oral/topical medications and laser therapy are numerous but unsatisfactory. Objective To compare the effectiveness of the dual wavelength long-pulsed 755-nm alexandrite/1,064-nm neodymium: yttrium-aluminum-garnet laser (LPAN) with that of 585-nm pulsed dye laser (PDL) for rosacea. Methods This was a randomized, single-blinded, comparative study. Full face received four consecutive monthly treatments with LPAN or PDL, followed-up for 6 months after the last treatment. Erythema index was measured by spectrophotometer, and digital photographs were evaluated by consultant dermatologists for physician's global assessment. Subjective satisfaction surveys and adverse effects were recorded. Results Forty-nine subjects with rosacea enrolled and 12 dropped out. There were no significant differences between LPAN and PDL in the mean reduction of the erythema index (p=0.812; 3.6% vs. 2.8%), improvement of physician's global assessment (p=1.000; 88.9% vs. 89.5%), and subject-rated treatment satisfaction (p=0.842; 77.8% vs. 84.2%). PDL showed more adverse effects including vesicles than LPAN (p=0.046; 26.3% vs. 0.0%). No other serious or permanent adverse events were observed in both treatments. Conclusion Both LPAN and PDL may be effective and safe treatments for rosacea. PMID:27746641

  9. Laser resonance ionization scheme development for tellurium and germanium at the dual Ti:Sa–Dye ISOLDE RILIS

    Energy Technology Data Exchange (ETDEWEB)

    Day Goodacre, T., E-mail: thomas.day.goodacre@cern.ch [CERN, CH-1211 Geneva 23 (Switzerland); School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom); Fedorov, D. [Petersburg Nuclear Physics Institute, 188350 Gatchina (Russian Federation); Fedosseev, V.N.; Forster, L.; Marsh, B.A. [CERN, CH-1211 Geneva 23 (Switzerland); Rossel, R.E. [CERN, CH-1211 Geneva 23 (Switzerland); Institut für Physik, Johannes Gutenberg Universität, D-55099 Mainz (Germany); Faculty of Design, Computer Science and Media, Hochschule RheinMain, Wiesbaden (Germany); Rothe, S.; Veinhard, M. [CERN, CH-1211 Geneva 23 (Switzerland)

    2016-09-11

    The resonance ionization laser ion source (RILIS) is the principal ion source of the ISOLDE radioactive beam facility based at CERN. Using the method of in-source laser resonance ionization spectroscopy, a transition to a new autoionizing state of tellurium was discovered and applied as part of a three-step, three-resonance, photo-ionization scheme. In a second study, a three-step, two-resonance, photo-ionization scheme for germanium was developed and the ionization efficiency was measured at ISOLDE. This work increases the range of ISOLDE RILIS ionized beams to 31 elements. Details of the spectroscopy studies are described and the new ionization schemes are summarized.

  10. Laser resonance ionization scheme development for tellurium and germanium at the dual Ti:Sa–Dye ISOLDE RILIS

    CERN Document Server

    Day Goodacre, T.; Fedosseev, V.N.; Forster, L.; Marsh, B.A.; Rossel, R.E.; Rothe, S.; Veinhard, M.

    2016-01-01

    The resonance ionization laser ion source (RILIS) is the principal ion source of the ISOLDE radioactive beam facility based at CERN. Using the method of in-source laser resonance ionization spectroscopy, a transition to a new autoionizing state of tellurium was discovered and applied as part of a three-step, three-resonance, photo-ionization scheme. In a second study, a three-step, two-resonance, photo-ionization scheme for germanium was developed and the ionization efficiency was measured at ISOLDE. This work increases the range of ISOLDE RILIS ionized beams to 31 elements. Details of the spectroscopy studies are described and the new ionization schemes are summarized.

  11. Laser resonance ionization scheme development for tellurium and germanium at the dual Ti:Sa-Dye ISOLDE RILIS

    Science.gov (United States)

    Day Goodacre, T.; Fedorov, D.; Fedosseev, V. N.; Forster, L.; Marsh, B. A.; Rossel, R. E.; Rothe, S.; Veinhard, M.

    2016-09-01

    The resonance ionization laser ion source (RILIS) is the principal ion source of the ISOLDE radioactive beam facility based at CERN. Using the method of in-source laser resonance ionization spectroscopy, a transition to a new autoionizing state of tellurium was discovered and applied as part of a three-step, three-resonance, photo-ionization scheme. In a second study, a three-step, two-resonance, photo-ionization scheme for germanium was developed and the ionization efficiency was measured at ISOLDE. This work increases the range of ISOLDE RILIS ionized beams to 31 elements. Details of the spectroscopy studies are described and the new ionization schemes are summarized.

  12. Acne vulgaris in the context of complex medical co-morbities: the management of severe acne vulgaris in a female with retinitis pigmentosa - utilizing pulse dye laser in conjunction with medical therapy.

    Science.gov (United States)

    Shariff, Ayesha; Keck, Laura; Zlotoff, Barrett

    2014-03-17

    Acne vulgaris is a pervasive inflammatory disorder of the skin, with multiple etiologies and treatment options. Although first-line therapies exist, it is often the case that a patient will present with an underlying disorder that prohibits the use of most currently accepted treatment modalities. We present a patient with severe acne vulgaris and a history of retinitis pigmentosa who was treated with 595 nanometer pulsed dye laser therapy, in conjunction with therapeutic alternatives to first-line acne medications. Our patient exhibited a significant and sustained improvement with the combined use of 595 nanometer pulsed dye laser, Yaz (drospirenone-ethinyl estradiol), dapsone, topical metronidazole, sodium-sulfacetamide wash, and topical azelaic acid. The positive results in this case, suggest that this combined treatment modality may serve as an example of a safe and effective treatment alternative in the management of acne vulgaris complicated by medical co-morbidities that contraindicate the use of most first-line treatment options.

  13. Thermal birefringence-compensated linear intracavity frequency doubled Nd:YAG rod laser with 73 ns pulse duration and 160Wgreen output power

    Indian Academy of Sciences (India)

    S K Sharma; A J Singh; P K Gupta; P Hedaoo; P K Mukhopadhyay; K Ranganathan; K S Bindra; S M Oak

    2014-02-01

    In a thermally birefringence-compensated linear cavity configuration, ∼160 W of average green power by intracavity frequency doubling of AO Q-switched Nd:YAG/LBO-based laser is demonstrated. The corresponding optical to optical conversion efficiency is estimated to be ∼12.7%. The pulse repetition rate is 20 kHz with the individual pulse duration of 73 ns. The beam quality parameter is measured to be 18.

  14. Near-infrared laser photothermal therapy and photodynamic inactivation of cells by using gold nanoparticles and dyes

    Science.gov (United States)

    Akchurin, George G.; Akchurin, Garif G.; Bogatyrev, Vladimir A.; Maksimova, Irina L.; Seliverstov, George A.; Terentyuk, George S.; Khlebtsov, Boris N.; Khlebtsov, Nikolai G.; Tuchin, Valery V.

    2007-09-01

    Light-induced inactivation of dynamic response of somatic frog nerve on electrical pulsed excitation was study ex vivo. The light-sensitive Indocianin Green has been used on photodynamic induced inactivation of the processes generation nerve pulses. Inactivation of consequence action potential of somatic frog nerve using excitation of electrical pulsed was achieved by irradiation with diode laser light in a IR spectral region (λ=810 nm, P~1W/cm2) in the case of Indocianin green. It was discovered that Indocianine green decrease of the amplitude compound action potential of the ensemble neurons. Experiments show effective destruction of cancer cells of ear, mouth and skin by local injection of plasmon resonant gold nanoshells and semiconductor laser (810 nm) irradiation. For destruction such tumors pulse duration was not less than 1microsecond and pulse separation 10 at average power density 1-3 W/sm2 and energy density 100-200 J/sm2

  15. Efficacy of treating children with anterior commissure and true vocal fold respiratory papilloma with the 585-nm pulsed-dye laser.

    Science.gov (United States)

    Hartnick, Christopher J; Boseley, Mark E; Franco, Ramon A; Cunningham, Michael J; Pransky, Seth

    2007-02-01

    To report preliminary results regarding the safety and efficacy of the 585-nm pulsed-dye laser (PDL) for the treatment of juvenile-onset recurrent respiratory papillomatosis (JORRP) in the pediatric population. Prospective longitudinal cohort study. Two pediatric otolaryngology referral centers. Twenty-three pediatric patients ranging in age from 6 months to 17 years. The 585-nm PDL was used for at least 1 treatment on each of these patients to treat JORRP of the true vocal folds or anterior commissure. Complications from the use of the 585-nm PDL in the treatment of JORRP. There was no evidence of anterior commissure webbing or true vocal fold scarring in this group of 23 patients followed up for 3 months to 1 year. The 585-nm PDL seems to be a safe instrument for treatment of JORRP. There is the potential that improved voice outcomes may be apparent when compared with traditional therapies because the vocal fold epithelium seems to be unharmed when treated with this method. Furthermore, the lack of epithelial damage incurred by the 585-nm PDL should enable more aggressive surgical excision of anterior commissure disease. Further prospective longitudinal studies examining voice outcomes are needed.

  16. Morphoelastic rods. Part I: A single growing elastic rod

    KAUST Repository

    Moulton, D.E.

    2013-02-01

    A theory for the dynamics and statics of growing elastic rods is presented. First, a single growing rod is considered and the formalism of three-dimensional multiplicative decomposition of morphoelasticity is used to describe the bulk growth of Kirchhoff elastic rods. Possible constitutive laws for growth are discussed and analysed. Second, a rod constrained or glued to a rigid substrate is considered, with the mismatch between the attachment site and the growing rod inducing stress. This stress can eventually lead to instability, bifurcation, and buckling. © 2012 Elsevier Ltd. All rights reserved.

  17. Learning with Rods: One Account.

    Science.gov (United States)

    Cherry, Donald Esha

    This paper discusses one English as a Second Language (ESL) teacher's attempts to use cuisenaire rods as a language learning tool. Cuisenaire rods (sometimes called algebricks) vary in size from 1 x 1 x 10 centimeter sticks to 1 x 1 x 1 centimeter cubes, with each of the 10 sizes a different color. Although such rods have been used to teach…

  18. Comparing the effects of conventional method, pulse dye laser and erbium laser for the treatment of hypertrophic scars in Iranian patients

    Directory of Open Access Journals (Sweden)

    Mahmod Omranifard

    2007-12-01

    Full Text Available BACKGROUND: Hypertrophic scar is an elevated scar with ugly appearance that isn’t acceptable even in reconstructive surgery. Unfortunately, there is no standard and effective treatment for it. Conventional treatments such as corticosteroid injection and garment usage have limited effectiveness. In recent year, laser is suggested for reduction of the volume and height of these scars. But in different studies, different results from very effective to ineffective were reported for this type of treatment.
    METHODS: This study was a single blind randomized clinical trial that was done on three groups. In each group, 40 patients with hypertrophic scar were included. In group one PDL, group 2 Erbium laser and in group 3 corticosteroid were used. Scar improvement was assessed by the amount of decrease in Vancouver burn scar (VBS score; the higher the decrease, the better the improvement.
    RESULTS: Although the mean VBS score significantly decreased in all three groups after treatment, the decrease in mean VBS score in group 3 was significantly lower than the decrease in mean VBS scores of groups 1 and 2 (P values were 0.037 and 0.041, respectively.
    CONCLUSIONS: Some types of laser such as PDL and erbium can improve elevation and vascularity of hypertrophic scar. These types of treatment can use in hypertrophic scar management when vascularity and elevation of scar are unfavorable.
    KEY WORDS: PDL, hypertrophic scar, erbium laser, conventional treatment.

  19. Comparing the effects of conventional method, pulse dye laser and erbium laser for the treatment of hypertrophic scars in Iranian patients

    OpenAIRE

    Mahmod Omranifard; Mehdi Rasti

    2007-01-01

    BACKGROUND: Hypertrophic scar is an elevated scar with ugly appearance that isn’t acceptable even in reconstructive surgery. Unfortunately, there is no standard and effective treatment for it. Conventional treatments such as corticosteroid injection and garment usage have limited effectiveness. In recent year, laser is suggested for reduction of the volume and height of these scars. But in different studies, different results from very effective to ineff...

  20. Ultra-broad range organic solid-state laser from a dye-doped holographic grating quasi-waveguide configuration

    Science.gov (United States)

    Liu, Minghuan; Liu, Yonggang; Peng, Zenghui; Mu, Quanquan; Cao, Zhaoliang; Lu, Xinghai; Ma, Ji; Xuan, Li

    2017-08-01

    This paper reports the ultra-broad 149.1 nm lasing emission from 573.2 to 722.3 nm using a simple [4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran] (DCM)-doped holographic polymer-dispersed liquid crystal (HPDLC) grating quasi-waveguide configuration by varying the grating period. The lasing emission beams show s-polarization property. The quasi-waveguide structure, which contained the cover glass, the DCM-doped HPDLC grating, the semiconducting polymer film poly[-methoxy-5-(2‧-ethyl-hexyloxy)-1,4-phenylene-vinylene] (MEH-PPV), and the substrate were confirmed to decrease lasing threshold and broaden lasing wavelength. The operational lifetime of the device is 240 000 pulses, which corresponds to an overall laser duration of more than 6 h at a repetition rate of 10 Hz. In addition, the dual-wavelength lasing range from the 8th and 9th order is over 40 nm. The electrical tunability of the dual-wavelength lasing emission is over 1 nm. The experimental results facilitated the decreased lasing threshold and broadened lasing wavelength range of organic solid-state lasers.

  1. Safety rod latch inspection

    Energy Technology Data Exchange (ETDEWEB)

    Leader, D.R.

    1992-02-01

    During an attempt to raise control rods from the 100 K reactor in December, one rod could not be withdrawn. Subsequent investigation revealed that a small button'' in the latch mechanism had broken off of the lock plunger'' and was wedged in a position that prevented rod withdrawal. Concern that this failure may have resulted from corrosion or some other metallurgical problem resulted in a request that SRL examine six typical latch mechanisms from the 100 L reactor by use of radiography and metallography. During the examination of the L-Area latches, a failed latch mechanism from the 100 K reactor was added to the investigation. Fourteen latches that had a history of problems were removed from K-Area and sent to SRL for inclusion in this study the week after the original seven assemblies were examined, bringing the total of latch assemblies discussed in this report to twenty one. Results of the examination of the K-Area latch that initiated this study is not included in this report.

  2. Safety rod latch inspection

    Energy Technology Data Exchange (ETDEWEB)

    Leader, D.R.

    1992-02-01

    During an attempt to raise control rods from the 100 K reactor in December, one rod could not be withdrawn. Subsequent investigation revealed that a small ``button`` in the latch mechanism had broken off of the ``lock plunger`` and was wedged in a position that prevented rod withdrawal. Concern that this failure may have resulted from corrosion or some other metallurgical problem resulted in a request that SRL examine six typical latch mechanisms from the 100 L reactor by use of radiography and metallography. During the examination of the L-Area latches, a failed latch mechanism from the 100 K reactor was added to the investigation. Fourteen latches that had a history of problems were removed from K-Area and sent to SRL for inclusion in this study the week after the original seven assemblies were examined, bringing the total of latch assemblies discussed in this report to twenty one. Results of the examination of the K-Area latch that initiated this study is not included in this report.

  3. INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Limitation of high-power optical radiation by organic molecules: I. Substituted pyranes and cyanine dyes

    Science.gov (United States)

    Kopylova, T. N.; Svetlichnyi, Valerii A.; Mayer, G. V.; Reznichenko, A. V.; Podgaetskii, Vitalii M.; Ponomareva, O. V.; Samsonova, L. G.; Filinov, D. N.; Pomogaev, V. A.; Tel'minov, E. N.; Lapin, I. N.; Svetlichnaya, N. N.; Sinchenko, E. I.

    2003-11-01

    Photophysical processes proceeding in polyatomic organic molecules (pyran derivatives and cyanines) excited by high-power laser radiation at 532 nm are studied. Some properties of their changes depending on the structure, solvent, and excitation conditions are determined. The effect of limitation of high-power exciting radiation by the organic molecules is found. The maximum limitation (Kmax = 15.0 at the initial transmission equal to 70%) was observed for the cyanine derivative and is comparable to this effect for fullerenes C60, which are widely used as radiation limiters.

  4. Spectral characteristics and nonlinear studies of crystal violet dye

    Science.gov (United States)

    Sukumaran, V. Sindhu; Ramalingam, A.

    2006-03-01

    Solid-state dye-doped polymer is an attractive alternative to the conventional liquid dye solution. In this paper, the spectral characteristics and the nonlinear optical properties of the dye crystal violet are studied. The spectral characteristics of crystal violet dye doped poly(methylmethacrylate) modified with additive n-butyl acetate (nBA) are studied by recording its absorption and fluorescence spectra and the results are compared with the corresponding liquid mixture. The nonlinear refractive index of the dye in nBA and dye doped polymer film were measured using z-scan technique, by exciting with He-Ne laser. The results obtained are intercompared. Both the samples of dye crystal violet show a negative nonlinear refractive index. The origin of optical nonlinearity in the dye may be attributed due to laser-heating induced nonlinear effect.

  5. Primary Photoprocesses in Dyes and Other Complex Molecules.

    Science.gov (United States)

    1978-10-31

    photobiology are given . -~~~~~ 3.2 Reports and Manuscripts in Preparation TR— l3. A Study of the Photodegradation of the Blue—Green Laser Dye , AC3F , A...the contract a preliminary study of the photodegradation of the laser dye , AC3F [Blue—Green Dye Laser Development , Annual Report F4—75 , NELC F233 b...I AD—A0b2 568 WASHINGTON STATE UNIV PULLMAN DEPT OF CHEMISTRY FFG 713 ‘c — F, PRIMARY PHOTOPROCESSES IN DYES AND OTHER COMPLEX MOLECULES. (U) OCT 78

  6. Identification of a novel laser dye substrate of mammalian cytochromes P450: application in rapid kinetic analysis, inhibitor screening, and directed evolution.

    Science.gov (United States)

    Kumar, Santosh

    2007-08-01

    The author sought to develop a high-throughput activity screening assay to carry out rapid kinetic analysis, inhibitor screening, and directed evolution of cytochrome P450 2C enzymes. Initially, of the 9 fluorescent substrates and 10 P450 2C enzymes tested, several P450 2C enzymes showed > 1 nmol/min/nmol P450 activity in cumene hydroperoxide (CuOOH)-supported reaction with a laser dye, 7-dimethylamino-4-trifluoromethylcoumarin (C152). A high-throughput steady-state kinetic analysis of the human P450 2C8, 2C9, and 2C19 showed 1) k(cat) = 3 to 6 min(-1), 2) K(m, CuOOH) = 100 to 200 microM, and 3) S(50, C152) = 10 to 20 microM in the CuOOH system. In addition, P450 2C9 and 2C19 showed a very high k(ca)t (27 and 38 min(-1), respectively) in the nicotinamide adenine dinucleotide phosphate (NADPH)-supported reaction. Subsequently, when mammalian P450s from the other subfamilies were tested, P450 2B1dH, 2B4dH, 2B5dH, 3A4, and 3A5 exhibited a significant activity in both CuOOH and NADPH systems. Furthermore, a high-throughput activity screening assay using whole-cell suspensions of the human P450 2C8, 2C9, and 2C19 was optimized. Overall, the data suggested that C152 can be used as a model substrate for mammalian P450s in CuOOH-supported reaction to perform rapid kinetic analysis, inhibitor screening, and directed evolution.

  7. Treatment of port wine stains with pulsed dye laser: a retrospective study of 848 cases in Shandong Province, People’s Republic of China

    Directory of Open Access Journals (Sweden)

    Shi W

    2014-12-01

    Full Text Available Wenhao Shi,1–3 Jinliang Wang,4,5 Yan Lin,4,5 Jianhui Geng,4,5 Haixia Wang,4,5 Yueqin Gong,4,5 Huaxu Liu,1,4,5 Furen Zhang1–4 1Shandong Provincial Institute of Dermatology and Venereology, Shandong Academy of Medical Sciences, 2Shandong Provincial Key Lab for Dermatovenereology, 3School of Medicine and Life Sciences, University of Jinan-Shandong Academy of Medical Sciences, 4Shandong Provincial Hospital for Skin Diseases, Shandong University, 5Shandong Provincial Medical Center for Dermatovenereology, Jinan, Shandong, People’s Republic of China Background: Currently, 595 nm pulsed dye laser (PDL therapy is offered as one of the effective treatments of port wine stains (PWSs. However, the efficacy of PDL differs in different populations.Objective: The purpose of the study was to investigate the efficacy, and related factors, of 595 nm PDL in the treatment of PWSs in Chinese patients with skin type III to IV. Methods: A total of 848 cases that were treated with PDL were enrolled and analyzed in this study. An independent dermatologist evaluated these lesions according to the before and after photographs.Results: The response rate (RR of all the 848 PWS patients was 69.9%, within which the cure rate was 6.3%. The patients aged ≤1 year had the highest RR (93.9%, whereas those treated after age 50 reacted the worst (RR =25%. We analyzed the anatomical distribution of the lesion and found that the temporal region had the highest lesion clearance (RR =75.3%, while the extremities had the lowest clearance (RR =44.5%. Compared with the patients whose lesion size was larger than 80 cm2, the patients with small lesion size, of 0–20 cm2, had better clinical effect (RR =73.8% vs 53.2%. The reactions of the patients with hyperplastic lesion were worse than those with red patches (RR =36.4% vs 71.7%. As well, increasing treatment numbers could achieve higher clearance rates (P=0.005.Conclusion: The PDL had a relatively high RR but a low clearance

  8. Force-extension curves for broken-rod macromolecules: Dramatic effects of different probing methods for two and three rods

    Energy Technology Data Exchange (ETDEWEB)

    Alexeev, A. V.; Maltseva, D. V.; Ivanov, V. A., E-mail: ivanov@polly.phys.msu.ru [Faculty of Physics, Moscow State University, 119991 Moscow (Russian Federation); Klushin, L. I., E-mail: leo@aub.edu.lb [Department of Physics, American University of Beirut, P.O. Box 11-0236, Beirut 1107 2020 (Lebanon); Skvortsov, A. M., E-mail: astarling@yandex.ru [Chemical-Pharmaceutical Academy, Prof. Popova 14, 197022 St. Petersburg (Russian Federation)

    2015-04-28

    We study force-extension curves of a single semiflexible chain consisting of several rigid rods connected by flexible spacers. The atomic force microscopy and laser optical or magnetic tweezers apparatus stretching these rod-coil macromolecules are discussed. In addition, the stretching by external isotropic force is analyzed. The main attention is focused on computer simulation and analytical results. We demonstrate that the force-extension curves for rod-coil chains composed of two or three rods of equal length differ not only quantitatively but also qualitatively in different probe methods. These curves have an anomalous shape for a chain of two rods. End-to-end distributions of rod-coil chains are calculated by Monte Carlo method and compared with analytical equations. The influence of the spacer’s length on the force-extension curves in different probe methods is analyzed. The results can be useful for interpreting experiments on the stretching of rod-coil block-copolymers.

  9. 脉冲染料激光治疗鲜红斑痣的临床疗效分析%Analysis of therapeutic effect of pulse dye laser in the treatment of port wine stains

    Institute of Scientific and Technical Information of China (English)

    谭志建; 童晓荣; 刘凌; 万兴祥

    2001-01-01

    利用脉冲染料激光器治疗了l617例鲜红斑痣患者,并从年龄的大小、皮损类型、面积大小、发生的部位及副作用进行了分组观察研究。其年龄小、淡红型皮损,面积小、发生于颈部、面部偏侧者疗效显著。1617例中仅有l例下唇发生 轻度增生性瘢痕。由此认为脉冲染料激光是目前治疗鲜红斑痣安全有效的方法。%One thousand six hundred and seventeen patients with port winestains were treated with the pulsed dye laser in the Laser Center. The patients were analysed according to the ages of patients type, size and location of the lesions, and side effects of the treatment. It was found that the therapeutic effect was better in patients with younger age, the lesions with light red color, small size and located on the neck and one side of the face. Mild hypertrophic scar occurred in one patient among 1617 patients treated. The conclusion is that the pulsed dye laser is a safe and effective method for the treatment of port wine stains.

  10. Growth control of ZnO nano-rod with various seeds and photovoltaic application

    Science.gov (United States)

    Seo, Hyunwoong; Wang, Yuting; Uchida, Giichiro; Kamataki, Kunihiro; Itagaki, Naho; Koga, Kazunori; Shiratani, Masaharu

    2013-06-01

    ZnO has attracted much interesting as one of unique materials. Especially, it is suitable for the easy fabrication of nano-structures such as rod, wire and tube as well as particles. ZnO nano-rod is one of good sensitized electrodes because it has good electron transfer and is easily fabricated. In the chemical bath deposition process, seed layer plays an important role in the growth of nano-rod. This work investigated and analyzed the effect of seed layer on the growth of ZnO nano-rod. Fabricated nano-rods were applied to dye-sensitized solar cell. For better performance, ZnO was surface-modified by TiO2. Surface-modified ZnO had improved electron transfer and wider surface area. Consequently, the current and fill factor were much improved and overall performance was also enhanced with them.

  11. Cone rod dystrophies

    Directory of Open Access Journals (Sweden)

    Hamel Christian P

    2007-02-01

    Full Text Available Abstract Cone rod dystrophies (CRDs (prevalence 1/40,000 are inherited retinal dystrophies that belong to the group of pigmentary retinopathies. CRDs are characterized by retinal pigment deposits visible on fundus examination, predominantly localized to the macular region. In contrast to typical retinitis pigmentosa (RP, also called the rod cone dystrophies (RCDs resulting from the primary loss in rod photoreceptors and later followed by the secondary loss in cone photoreceptors, CRDs reflect the opposite sequence of events. CRD is characterized by primary cone involvement, or, sometimes, by concomitant loss of both cones and rods that explains the predominant symptoms of CRDs: decreased visual acuity, color vision defects, photoaversion and decreased sensitivity in the central visual field, later followed by progressive loss in peripheral vision and night blindness. The clinical course of CRDs is generally more severe and rapid than that of RCDs, leading to earlier legal blindness and disability. At end stage, however, CRDs do not differ from RCDs. CRDs are most frequently non syndromic, but they may also be part of several syndromes, such as Bardet Biedl syndrome and Spinocerebellar Ataxia Type 7 (SCA7. Non syndromic CRDs are genetically heterogeneous (ten cloned genes and three loci have been identified so far. The four major causative genes involved in the pathogenesis of CRDs are ABCA4 (which causes Stargardt disease and also 30 to 60% of autosomal recessive CRDs, CRX and GUCY2D (which are responsible for many reported cases of autosomal dominant CRDs, and RPGR (which causes about 2/3 of X-linked RP and also an undetermined percentage of X-linked CRDs. It is likely that highly deleterious mutations in genes that otherwise cause RP or macular dystrophy may also lead to CRDs. The diagnosis of CRDs is based on clinical history, fundus examination and electroretinogram. Molecular diagnosis can be made for some genes, genetic counseling is

  12. Optical limiting effect in a two-photon absorption dye doped solid matrix

    Science.gov (United States)

    He, Guang S.; Bhawalkar, Jayant D.; Zhao, Chan F.; Prasad, Paras N.

    1995-10-01

    We recently reported a new lasing dye, trans-4-[p-(N-ethyl-N-hydroxylethylamino)styryl]-N-methylpyridinium tetraphenylborate (ASPT), which has also been shown to possess a strong two-photon absorption (TPA) and subsequent frequency upconversion fluorescence behavior when excited with near infrared laser radiation. Based on the TPA mechanism, a highly efficient optical limiting performance has been demonstrated in a 2 cm long ASPT-doped epoxy rod pumped with 1.06 μm Q-switched laser pulses at 50-250 MW/cm2 intensity levels. The measured nonlinear absorption coefficient reached 6 cm/GW for the tested sample of dopant concentration d0=4×10-3 M/L. The molecular TPA cross section of ASPT in the epoxy matrix is estimated as σ2=2.5×10-18 cm4/GW or σ2'=4.7×10-46 cm4/photon/s, respectively. Two-photon pumped cavity lasing is also observed in an ASPT-doped polymer rod.

  13. Active Brownian rods

    Science.gov (United States)

    Peruani, Fernando

    2016-11-01

    Bacteria, chemically-driven rods, and motility assays are examples of active (i.e. self-propelled) Brownian rods (ABR). The physics of ABR, despite their ubiquity in experimental systems, remains still poorly understood. Here, we review the large-scale properties of collections of ABR moving in a dissipative medium. We address the problem by presenting three different models, of decreasing complexity, which we refer to as model I, II, and III, respectively. Comparing model I, II, and III, we disentangle the role of activity and interactions. In particular, we learn that in two dimensions by ignoring steric or volume exclusion effects, large-scale nematic order seems to be possible, while steric interactions prevent the formation of orientational order at large scales. The macroscopic behavior of ABR results from the interplay between active stresses and local alignment. ABR exhibit, depending on where we locate ourselves in parameter space, a zoology of macroscopic patterns that ranges from polar and nematic bands to dynamic aggregates.

  14. Control of Rod-Rod Interactions in Poly(3-alkylthiophenes)

    Science.gov (United States)

    Ho, Victor; Boudouris, Bryan W.; Segalman, Rachel A.

    2010-03-01

    Poly(3-hexylthiophene) is a commonly used semiconducting polymer because of its relatively high charge transport ability, low band gap, and solution processiblity. Strong intermolecular interactions lead to the formation of nanofibers during crystallization, which prevents long-range microstructural ordering. We show rod-rod interactions, parameterized by the Maier-Saupe parameter, can be controlled by rational polythiophene side chain design. Effects of side chain passivation are evidenced by a depressed melting temperature and the presence of a liquid crystalline region. Additionally, the Maier-Saupe parameters are estimated for poly(3-dodecylthiophene) and poly(3-ethylhexylthiophene); the relative magnitudes of each are related to the interchain spacings obtained by x-ray diffraction experiments. The systematic tuning of the rod-rod interactions in polythiophenes allows for manipulation of the ratio of Maier-Saupe to the Flory-Huggins parameter, a crucial value in obtaining long-range order in rod-coil block copolymer morphologies.

  15. Waterless Textile Dyeing

    OpenAIRE

    Odabaşoğlu, Hakkı Yasin; AVİNÇ, Osman Ozan; Arzu YAVAŞ

    2013-01-01

    Supercritical carbon dioxide (scCO), having liquid-like densities, hereby provides hydrophobic dyes an advantage on dissolving. Their gas-like low viscosities and diffusion properties can lead to shorter dyeing durations compared to conventional water dyeing process. Supercritical carbon dioxide dyeing, a novel dyeing process, is an anhydrous dyeing and this process involves the use of less energy and chemicals than conventional water dyeing processes resulting in a potential of up to 50% low...

  16. Femtosecond laser enhanced current in a thermionic diode with barium vapor

    Science.gov (United States)

    Makdisi, Y.; Kokaj, J.; Afrousheh, K.; Mathew, J.; Nair, R.; Pichler, G.

    2014-11-01

    We studied the signal from a thermionic diode when a femtosecond laser beam was spatially overlapped by an excimer pumped dye laser beam. The nanosecond dye laser was scanned from 435 to 438 nm in order to excite the autoionizing levels of barium by two photon absorption. The broadband ultrashort laser light was centered at 427 nm, which is also above the first ionization limit of barium. The bias voltage between the cell body and the tungsten rod (set at either 9 or 0 V) was used to collect electrons after the barium ions had been created by multiphoton (auto) ionization. The overall background of the thermionic signal was appreciably elevated due to the two photon ionization by the broadband femtosecond laser. We measured the thermionic signal with and without femtosecond laser overlap, and with a biasless and biased thermionic diode. The effect of the femtosecond laser was appreciable enhancement of the background ionization continuum. This was especially visible in the presence of noble gases at pressure of 50 mbar. Argon produced the largest and helium produced the smallest enhancement in the background continuum. In addition, we observed a few broad spectral features of a presumably collision induced nature.

  17. Cuisenaire Rods Go to College.

    Science.gov (United States)

    Chinn, Phyllis; And Others

    1992-01-01

    Presents examples of questions and answers arising from a hands-on and exploratory approach to discrete mathematics using cuisenaire rods. Combinatorial questions about trains formed of cuisenaire rods provide the setting for discovering numerical patterns by experimentation and organizing the results using induction and successive differences.…

  18. Lasers '92; Proceedings of the International Conference on Lasers and Applications, 15th, Houston, TX, Dec. 7-10, 1992

    Science.gov (United States)

    Wang, Charles P. (Editor)

    1993-01-01

    Papers from the conference are presented, and the topics covered include the following: x-ray lasers, excimer lasers, chemical lasers, high power lasers, blue-green lasers, dye lasers, solid state lasers, semiconductor lasers, gas and discharge lasers, carbon dioxide lasers, ultrafast phenomena, nonlinear optics, quantum optics, dynamic gratings and wave mixing, laser radar, lasers in medicine, optical filters and laser communication, optical techniques and instruments, laser material interaction, and industrial and manufacturing applications.

  19. Eulerian formulation of elastic rods

    Science.gov (United States)

    Huynen, Alexandre; Detournay, Emmanuel; Denoël, Vincent

    2016-06-01

    In numerous biological, medical and engineering applications, elastic rods are constrained to deform inside or around tube-like surfaces. To solve efficiently this class of problems, the equations governing the deflection of elastic rods are reformulated within the Eulerian framework of this generic tubular constraint defined as a perfectly stiff normal ringed surface. This reformulation hinges on describing the rod-deformed configuration by means of its relative position with respect to a reference curve, defined as the axis or spine curve of the constraint, and on restating the rod local equilibrium in terms of the curvilinear coordinate parametrizing this curve. Associated with a segmentation strategy, which partitions the global problem into a sequence of rod segments either in continuous contact with the constraint or free of contact (except for their extremities), this re-parametrization not only trivializes the detection of new contacts but also transforms these free boundary problems into classic two-points boundary-value problems and suppresses the isoperimetric constraints resulting from the imposition of the rod position at the extremities of each rod segment.

  20. Status of rod consolidation, 1988

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, W.J.

    1989-01-01

    It is estimated that the spent fuel storage pools at some domestic light-water reactors will run out of space before 2003, the year that the US Department of Energy currently predicts it will have a repository available. Of the methods being studied to alleviate the problem, rod consolidation is one of the leading candidates for achieving more efficient use of existing space in spent fuel storage pools. Rod consolidation involves mechanically removing all the fuel rods from the fuel assembly hardware (i.e., the structural components) and placing the fuel rods in a close-packed array in a canister without space grids. A typical goal of rod consolidation systems is to insert the fuel rods from two fuel assemblies into a canister that has the same exterior dimensions as one standard fuel assembly (i.e., to achieve a consolidation or compaction ratio of 2:1) and to compact the nonfuel-bearing structural components from those two fuel assemblies by a factor of 10 to 20. This report provides an overview of the current status of rod consolidation in the United States and a small amount of information on related activities in other countries. 85 refs., 36 figs., 5 tabs.

  1. Hair dye poisoning

    Science.gov (United States)

    Hair tint poisoning ... Different types of hair dye contain different harmful ingredients. The harmful ingredients in permanent dyes are: Naphthylamine Other aromatic amino compounds Phenylenediamines Toluene ...

  2. Topological mixing with ghost rods

    Science.gov (United States)

    Gouillart, Emmanuelle; Thiffeault, Jean-Luc; Finn, Matthew D.

    2006-03-01

    Topological chaos relies on the periodic motion of obstacles in a two-dimensional flow in order to form nontrivial braids. This motion generates exponential stretching of material lines, and hence efficient mixing. Boyland, Aref, and Stremler [J. Fluid Mech. 403, 277 (2000)] have studied a specific periodic motion of rods that exhibits topological chaos in a viscous fluid. We show that it is possible to extend their work to cases where the motion of the stirring rods is topologically trivial by considering the dynamics of special periodic points that we call “ghost rods”, because they play a similar role to stirring rods. The ghost rods framework provides a new technique for quantifying chaos and gives insight into the mechanisms that produce chaos and mixing. Numerical simulations for Stokes flow support our results.

  3. Nuclear Fuel Test Rod Fabrication for Data Acquisition Test

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Chang-Young; Hong, Jin-Tae; Kim, Ka-Hye; Huh, Sung-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    A nuclear fuel test rod must be fabricated with precise welding and assembly technologies, and confirmed for their soundness. Recently, we have developed various kinds of processing systems such as an orbital TIG welding system, a fiber laser welding system, an automated drilling system and a helium leak analyzer, which are able to fabricate the nuclear fuel test rods and rigs, and keep inspection systems to confirm the soundness of the nuclear fuel test rods and rids. The orbital TIG welding system can be used with two kinds of welding methods. One can perform the round welding for end-caps of a nuclear fuel test rod by an orbital head mounted in a low-pressure chamber. The other can do spot welding for a pin-hole of a nuclear fuel test rod in a high-pressure chamber to fill up helium gas of high pressure. The fiber laser welding system can weld cylindrical and 3 axis samples such as parts of a nuclear fuel test rod and instrumentation sensors which is moved by an index chuck and a 3 axis (X, Y, Z) servo stage controlled by the CNC program. To measure the real-time temperature change at the center of the nuclear fuel during the irradiation test, a thermocouple should be instrumented at that position. Therefore, a hole needs to be made at the center of fuel pellet to instrument the thermocouple. An automated drilling system can drill a fine hole into a fuel pellet without changing tools or breaking the work-piece. The helium leak analyzer (ASM-380 model of DEIXEN Co.) can check the leak of the nuclear fuel test rod filled with helium gas. This paper describes not only the assembly and fabrication methods used by the process systems, but also the results of the data acquisition test for the nuclear fuel test rod. A nuclear fuel test rod for the data acquisition test was fabricated using the welding and assembling echnologies acquired from previous tests.

  4. Electrochemical Studies of 1,4-Bis[2-(2-pyridyl)-vinyl] Benzene and 1,4-Bis[2-(4-pyridyl) vinyl] Benzene Laser Dyes via Cyclic Voltammetry, Convolutive Voltammetry and Digital Simulation Methods

    Institute of Scientific and Technical Information of China (English)

    EL-DALY, Samy A; EL-HALLAG,Ibrahirn S; EBEED, Ezeiny M; GHONEIM, Mohamed M

    2009-01-01

    Electrochemical properties of two diolefinic laser dyes namely 1,4-bis[2-(2-pyddyl)-vinyl] benzene (2PVB) and 1,4-bis[2-(4-pyridyl) vinyl] benzene (4PVB) have been investigated using cyclic voltammetry and convolutive voltammetry combined with digital simulation at a platinum electrode in 0.1 mol/L tetrabutyl ammonium perchlo-rate (TBAP) in the two different solvents acetonitrile (CH3CN) and dimethylformamide (DMF). The species were reduced via consumption of two sequential electrons to form radical anion and dianion. In switching the potential to positive direction, the two compounds were oxidized by loss of one electron, which was followed by a fast isomeri-sation process. The electrode reaction pathway and the electrochemical parameters of the investigated compounds were determined using cyclic voltammetry. The extracted electrochemical parameters were verified and confirmed via digital simulation and convolutive voltammetry methods.

  5. Polymer laser bio-sensors

    DEFF Research Database (Denmark)

    Kristensen, Anders; Vannahme, Christoph; Hermannsson, Pétur Gordon

    2014-01-01

    Organic dye based distributed feed-back lasers, featuring narrow linewidth and thus high quality spectral resolution, are used as highly sensitive refractive index sensors. The design, fabrication and application of the laser intra-cavity sensors are discussed....

  6. A novel method for the synthesis of coumarin laser dyes derived from 3-(1H-benzoimidazol-2-yl coumarin-2-one under microwave irradiation

    Directory of Open Access Journals (Sweden)

    Ghasem Bakhtiari

    2014-12-01

    Full Text Available We want to achieve the synthesis of 3-(1H-benzoimidazol-2-yl-7-(diethylamino coumarin-2-one (1, 3-(1H-benzoimidazol-2-yl-7-(dimethylamino coumarin-2-one (2, 3-(1H-benzoimidazol-2-yl coumarin-2-one (3 that are important dyes in industries (Soko owska et al., 2001. Methods for the synthesis of some of these compounds have been the title in some pervious patents, but enough information about separation and purification of them was not clearly indicated. We carried out several methods for the synthesis of the mentioned compound and purification with different yields. Now, we can synthesise these dyes under microwave irradiation in solid phase and solvent free methods with 80% yield, which is a high and remarkable percentage.

  7. The Third ATLAS ROD Workshop

    CERN Multimedia

    Poggioli, L.

    A new-style Workshop After two successful ATLAS ROD Workshops dedicated to the ROD hardware and held at the Geneva University in 1998 and in 2000, a new style Workshop took place at LAPP in Annecy on November 14-15, 2002. This time the Workshop was fully dedicated to the ROD-TDAQ integration and software in view of the near future integration activities of the final RODs for the detector assembly and commissioning. More precisely, the aim of this workshop was to get from the sub-detectors the parameters needed for T-DAQ, as well as status and plans from ROD builders. On the other hand, what was decided and assumed had to be stated (like EB decisions and URDs), and also support plans. The Workshop gathered about 70 participants from all ATLAS sub-detectors and the T-DAQ community. The quite dense agenda allowed nevertheless for many lively discussions, and for a dinner in the old town of Annecy. The Sessions The Workshop was organized in five main sessions: Assumptions and recommendations Sub-de...

  8. Polymer laser bio-sensors

    DEFF Research Database (Denmark)

    Kristensen, Anders; Vannahme, Christoph; Hermannsson, Pétur Gordon

    2014-01-01

    Organic dye based distributed feed-back lasers, featuring narrow linewidth and thus high quality spectral resolution, are used as highly sensitive refractive index sensors. The design, fabrication and application of the laser intra-cavity sensors are discussed.......Organic dye based distributed feed-back lasers, featuring narrow linewidth and thus high quality spectral resolution, are used as highly sensitive refractive index sensors. The design, fabrication and application of the laser intra-cavity sensors are discussed....

  9. Topological Optimization of Rod Mixers

    Science.gov (United States)

    Finn, Matthew D.; Thiffeault, Jean-Luc

    2006-11-01

    Stirring of fluid with moving rods is necessary in many practical applications to achieve homogeneity. These rods are topological obstacles that force stretching of fluid elements. The resulting stretching and folding is commonly observed as filaments and striations, and is a precursor to mixing. In a space-time diagram, the trajectories of the rods form a braid [1], and the properties of this braid impose a minimal complexity in the flow. We discuss how optimal mixing protocols can be obtained by a judicious choice of braid, and how these protocols can be implemented using simple gearing [2].[12pt] [1] P. L. Boyland, H. Aref, and M. A. Stremler, JFM 403, 277 (2000).[8pt] [2] J.-L. Thiffeault and M. D. Finn, http://arxiv.org/nlin/0603003

  10. Advanced gray rod control assembly

    Energy Technology Data Exchange (ETDEWEB)

    Drudy, Keith J; Carlson, William R; Conner, Michael E; Goldenfield, Mark; Hone, Michael J; Long, Jr., Carroll J; Parkinson, Jerod; Pomirleanu, Radu O

    2013-09-17

    An advanced gray rod control assembly (GRCA) for a nuclear reactor. The GRCA provides controlled insertion of gray rod assemblies into the reactor, thereby controlling the rate of power produced by the reactor and providing reactivity control at full power. Each gray rod assembly includes an elongated tubular member, a primary neutron-absorber disposed within the tubular member said neutron-absorber comprising an absorber material, preferably tungsten, having a 2200 m/s neutron absorption microscopic capture cross-section of from 10 to 30 barns. An internal support tube can be positioned between the primary absorber and the tubular member as a secondary absorber to enhance neutron absorption, absorber depletion, assembly weight, and assembly heat transfer characteristics.

  11. 普萘洛尔联合脉冲染料激光治疗婴幼儿血管瘤的护理体会%The nursing experience of propranolol combined with pulsed dye laser to treat infantile hemangioma

    Institute of Scientific and Technical Information of China (English)

    刘东平; 刘小加; 王晶; 罗明灿

    2016-01-01

    Objective This paper summarizes the nursing experience of propranolol combined with pulsed dye laser in the treatment of 75 cases of infantile hemangioma. Methods This stuty included the children with oral propranolol delivery methods, medication missionary. Preparation of pre-operative nursing care by Pulse Dye Laser treatment. In order to increase the safety of treatment, we used"parcels"and language exchange to reduce children with tampering and fear, assisted the doctor for laser treatment, used cold therapy and smear MEBO for wound immediately after treatment. The patients were given follow-up nursing care after discharge, medication guide and drug adverse reaction of observation,wound care and observation, reservation referral treatment time,let the children do not interrupt the care due to discharge. Results Application of propranolol combined pulsed dye laser treatment of infantile hemangioma clinical effect is remarkable. High quality of nursing and to carry out the continuity of care in the whole treatment process seamlessly. To guarantee children comprehensive nursing instruction, recover at an early date. Conclusion The treatment of infantile hemangioma is a long-term process, drug care, laser treatment, wound care and continuity of care for the whole treatment process to play a cooperative role in the treatment process.%目的:总结普萘洛尔联合脉冲染料激光治疗婴幼儿血管瘤75例的护理体会。方法:主要包括患儿口服普萘洛尔药物的给药方法,用药宣教;脉冲染料激光治疗术前护理准备工作,治疗时采用“包裹法”和语言交流,增加治疗安全性,协助医生进行激光治疗,治疗后即刻给予创面冷疗和涂抹美宝湿润烧伤膏;患儿出院后给予后续性护理,进行用药指导和药物不良反应的观察、创面护理及观察、预约复诊治疗时间。结果:应用普萘洛尔联合脉冲染料激光治疗婴幼儿血管瘤临床效果显著,

  12. Tunable laser applications

    CERN Document Server

    Duarte, FJ

    2008-01-01

    Introduction F. J. Duarte Spectroscopic Applications of Tunable Optical Parametric Oscillators B. J. Orr, R. T. White, and Y. He Solid-State Dye Lasers Costela, I. García-Moreno, and R. Sastre Tunable Lasers Based on Dye-Doped Polymer Gain Media Incorporating Homogeneous Distributions of Functional Nanoparticles F. J. Duarte and R. O. James Broadly Tunable External-Cavity Semiconductor Lasers F. J. Duarte Tunable Fiber Lasers T. M. Shay and F. J. Duarte Fiber Laser Overview and Medical Applications

  13. Laser Ion Source Project at IGISOL

    Energy Technology Data Exchange (ETDEWEB)

    Nieminen, A. [University of Manchester, Department of Physics and Astronomy (United Kingdom); Moore, I. D., E-mail: iain.moore@php.jyu.fi [University of Jyvaeskylae, Department of Physics (Finland); Billowes, J.; Campbell, P.; Flanagan, K. T. [University of Manchester, Department of Physics and Astronomy (United Kingdom); Geppert, Ch. [University of Mainz, Institut fuer Physik (Germany); Huikari, J.; Jokinen, A. [University of Jyvaeskylae, Department of Physics (Finland); Kessler, T. [University of Mainz, Institut fuer Physik (Germany); Marsh, B. [University of Manchester, Department of Physics and Astronomy (United Kingdom); Penttilae, H.; Rinta-Antila, S. [University of Jyvaeskylae, Department of Physics (Finland); Tordoff, B. [University of Manchester, Department of Physics and Astronomy (United Kingdom); Wendt, K. D. A. [University of Mainz, Institut fuer Physik (Germany); Aystoe, J. [University of Jyvaeskylae, Department of Physics (Finland)

    2005-04-15

    The application of laser ionisation is being developed for the IGISOL mass separator facility in Jyvaeskylae, Finland. The conceived laser ion source will have two independent pulsed laser systems based on all solid-state lasers and dye lasers for maximal coverage of ionisation schemes throughout the periodic table. A laser ion source trap, LIST, method will be pursued for optimal selectivity.

  14. The laser in urology

    Science.gov (United States)

    Hofstetter, Alfons G.

    2002-10-01

    Laser is an acronym for a physical principle and means: Light Amplification by stimulated Emission of Radiation. This principle offers a lot of tissue/light effects caused by the parameters: power density/time and the special qualities of the laser light. Nowadays for diagnosis and therapy following lasers are used in urology: Krypton- and Dye-lasers as well as the Neodymium-YAG- (nd:YAG-), Holmium-YAG (Ho:YAG-), Diode-, Argon- and the CO2-lasers.

  15. Nonlinear photonic diode behavior in energy-graded core-shell quantum well semiconductor rod.

    Science.gov (United States)

    Ko, Suk-Min; Gong, Su-Hyun; Cho, Yong-Hoon

    2014-09-10

    Future technologies require faster data transfer and processing with lower loss. A photonic diode could be an attractive alternative to the present Si-based electronic diode for rapid optical signal processing and communication. Here, we report highly asymmetric photonic diode behavior with low scattering loss, from tapered core-shell quantum well semiconductor rods that were fabricated to have a large gradient in their bandgap energy along their growth direction. Local laser illumination of the core-shell quantum well rods yielded a huge contrast in light output intensities from opposite ends of the rod.

  16. Measurement for titanium density distribution on Ti:sapphire rods for high intensity pump source

    Energy Technology Data Exchange (ETDEWEB)

    Usami, Tsutomu; Nishimura, Akihiko; Sugiyama, Akira [Japan Atomic Energy Research Inst., Kizu, Kyoto (Japan). Kansai Research Establishment

    2001-10-01

    A Ti:sapphire rod of 190 mm length made by Czochralski (CZ) technique was used in the flashlamp pumped high intensity laser for Yb:glass chirped pulse amplification. In the absorption spectroscopy of the rod immersed in an index matching liquid of methylene iodide, heterogeneous Ti{sup 3+} density distribution was measured along the direction of length. It has been first clarified that the Ti:sapphire rod grown by the CZ technique has 20% difference of the Ti{sup 3+} density at the both ends. (author)

  17. Orthopaedic metal devices coated with a novel antiseptic dye for the prevention of bacterial infections.

    Science.gov (United States)

    Bahna, Paul; Dvorak, Tanya; Hanna, Hend; Yasko, Alan W; Hachem, Ray; Raad, Issam

    2007-05-01

    Gendine is a novel antiseptic dye with broad-spectrum antimicrobial activity that may be used to coat plastics and metal devices. Our objective was to determine the efficacy of gendine-coated orthopaedic metal devices in preventing methicillin-resistant Staphylococcus aureus (MRSA) colonisation. Stainless steel and titanium Schanz rods were coated with gendine. The zone of inhibition (ZoI) around the rods with and without gamma-irradiation was determined by a modified Kirby-Bauer method. A previously published bioprosthetic biofilm colonisation model, modified Kuhn's method, was used to determine the adherence of MRSA to coated and uncoated rods, with and without irradiation, after insertion into bovine bone and after 3 months shelf life followed by 2 weeks of immersion in serum. The gendine-coated Schanz metal rods showed a net ZoI of 16 mm against MRSA before and after irradiation. Gendine-coated rods showed no biofilm formation (0 colony-forming units (CFU)), which was a significant reduction (P5000 CFU). Coated rods exposed to high-dose gamma-irradiation and coated rods drilled into bone also showed significant efficacy (P<0.001) in preventing biofilm adherence. After 2 weeks, gendine-coated rods maintained significant durability (P<0.01), resulting in 90% reduction in MRSA biofilm adherence compared with uncoated control rods. Results indicate that gendine-coated metal rods are highly efficacious in the prevention of MRSA biofilm.

  18. Control rods in LMFBRs: a physics assessment

    Energy Technology Data Exchange (ETDEWEB)

    McFarlane, H.F.; Collins, P.J.

    1982-08-01

    This physics assessment is based on roughly 300 control rod worth measurements in ZPPR from 1972 to 1981. All ZPPR assemblies simulated mixed-oxide LMFBRs, representing sizes of 350, 700, and 900 MWe. Control rod worth measurements included single rods, various combinations of rods, and Ta and Eu rods. Additional measurements studied variations in B/sub 4/C enrichment, rod interaction effects, variations in rod geometry, neutron streaming in sodium-filled channels, and axial worth profiles. Analyses were done with design-equivalent methods, using ENDF/B Version IV data. Some computations for the sensitivities to approximations in the methods have been included. Comparisons of these analyses with the experiments have allowed the status of control rod physics in the US to be clearly defined.

  19. Dyeing Properties of Basofil Fiber

    Institute of Scientific and Technical Information of China (English)

    JIANG Hong; DAI Jin-jin

    2002-01-01

    The structures and properties of Basofil fiber were studied using X- rays small angle diffraction analysis,differential- scanuing calorimeter and scanning electron microscopy. Disperse dyes, acid dyes and reactive dyes had been tried for dyeing Basefil fiber. It was shown disperse dyes were superior to other ones. The two series of high temperature dyes and low temperature dyes were compared for their suitability for Basofil fiber, and their dyeing behaviors were determined.

  20. Multicapillary electrophoresis of unlabeled DNA fragments with high-sensitive laser-induced fluorescence detection by counter-current migration of intercalation dye.

    Science.gov (United States)

    Benesova-Minarikova, Lucie; Fantova, Lucie; Minarik, Marek

    2005-11-01

    Analysis of PCR fragments for applications, such as screening of nucleotide polymorphisms, detection of somatic mutations, or quantification of reverse-transcription PCR products, becomes central in clinical research as well as preventive testing, diagnostic screening, and pharmacogenomic genotyping. A variety of CE techniques, utilizing great potential of multicapillary-array sequencers, is now commonly applied in prevention, diagnosis, and treatment of a wide range of genetic diseases (cancer, cardiovascular, and neurodegenerative diseases, etc.). Costs of fluorescently labeled primers is often a major factor in large-scale projects requiring mutation analysis in hundreds or thousands of samples. In the present paper we introduce a simple approach of detecting unlabeled DNA fragments through intercalation without a need for adding intercalator to the separation polymer matrix. The dye is only added to the anode reservoir, and mixing with the separated DNA fragments takes place upon its migration opposite to the direction of the CE separation. Using two common intercalating dyes (ethidium bromide and SYBR Green II) we present this method as a tool for routine PCR detection and quantification.

  1. Benzidine Dyes Action Plan

    Science.gov (United States)

    This Action Plan addresses the use of benzidine-based dyes and benzidine congener-based dyes, both metalized and non-metalized, in products that would result in consumer exposure, such as for use to color textiles.

  2. Stress Analysis of Single Spacer Grid Support considering Fuel Rod

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Y. G.; Jung, D. H.; Kim, J. H. [Chungnam National University, Daejeon (Korea, Republic of); Park, J. K.; Jeon, K. L. [Korea Nuclear Fuel, Daejeon (Korea, Republic of)

    2010-10-15

    Pressurized water reactor (PWR) nuclear fuel assembly is mainly composed of a top-end piece, a bottom-end piece, lots of fuel rods, and several spacer grids. Among them, the main function of spacer grid is protecting fuel rods from Fluid Induced Vibration (FIV). The cross section of spacer grid assembled by laser welding in upper and lower point. When the fuel rod inserted in spacer gird, spring and dimple and around of welded area got a stresses. The main hypothesis of this analysis is the boundary area of HAZ and base metal can get a lot of damage than other area by FIV. So, design factors of spacer grid mainly considered to preventing the fatigue failure in HAZ and spring and dimple of spacer grid. From previous researching, the environment in reactor verified. Pressure and temperature of light water observed 15MPa and 320 .deg. C, and vibration of the fuel rod observed within 0 {approx} 50Hz. In this study, mechanical properties of zirconium alloy that extracted from the test and the spacer grid model which used in the PWR were applied in stress analyzing. General-purpose finite element analysis program was used ANSYS Workbench 12.0.1 version. 3-D CAD program CATIA was used to create spacer grid model

  3. Tunable Diode Laser Absorption Spectroscopy Verification Analysis for Use in the Combustion Optimization and Analysis Laser Laboratory

    Science.gov (United States)

    2009-03-01

    5 Figure 4: Coherent Verdi -5 Nd:YAG laser........................................................................ 6 Figure 5: Cheetah Series...broadband dye laser also assembled by ISSI, the Verdi 5 Nd:YVO4 laser produced by Coherent, and 5 the DFB diode Laser produced by Cheetah...narrowband dye laser with frequency doubler 6 Figure 4: Coherent Verdi -5 Nd:YAG laser Figure 5: Cheetah Series DFB diode laser 1.4

  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. 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.

  6. 21 CFR 876.4270 - Colostomy rod.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Colostomy rod. 876.4270 Section 876.4270 Food and... GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4270 Colostomy rod. (a) Identification. A colostomy rod is a device used during the loop colostomy procedure. A loop of colon is surgically brought out...

  7. Solitary waves on nonlinear elastic rods. II

    DEFF Research Database (Denmark)

    Sørensen, Mads Peter; Christiansen, Peter Leth; Lomdahl, P. S.

    1987-01-01

    In continuation of an earlier study of propagation of solitary waves on nonlinear elastic rods, numerical investigations of blowup, reflection, and fission at continuous and discontinuous variation of the cross section for the rod and reflection at the end of the rod are presented. The results...

  8. Hydraulic Actuator for Ganged Control Rods

    Science.gov (United States)

    Thompson, D. C.; Robey, R. M.

    1986-01-01

    Hydraulic actuator moves several nuclear-reactor control rods in unison. Electromagnetic pump pushes liquid lithium against ends of control rods, forcing them out of or into nuclear reactor. Color arrows show lithium flow for reactor startup and operation. Flow reversed for shutdown. Conceived for use aboard spacecraft, actuator principle applied to terrestrial hydraulic machinery involving motion of ganged rods.

  9. Hexagonal microlasers based on organic dyes in nanoporous crystals

    CERN Document Server

    Braun, I; Laeri, F; Nöckel, J U; Schulz-Ekloff, G; Schueth, F; Vietze, U; Weiss, O; Woehrle, D; Braun, Ingo; Ihlein, Guido; Laeri, Franco; Noeckel, Jens U.; Schulz-Ekloff, Guenter; Schueth, Ferdi; Vietze, Uwe; Weiss, Ozlem; Woehrle, Dieter

    2000-01-01

    Molecular sieves, such as nanoporous AlPO_4-5, can host a wide variety of laser active dyes. We embedded pyridine 2 molecules as a representative of a commercially available dye which fits into the channel pores of the host matrix. Many efficient dye molecules, such as rhodamines, do not fit into the pores. But the amount of encapsulated dyes can be increased by modifying the structure of the dyes such that they match the host templates. The resulting microlasers have properties that depend on size and shape of the microresonators, and we discuss a model for microscopic hexagonal ring resonators. In terms of pump needed to reach lasing threshold molecular sieve microlasers are comparable to VCSELs. For dyes which fit into the pores we observed a partial regeneration of photo-induced damage.

  10. Laser-Activated Shape Memory Polymer Microactuator for Thrombus Removal Following Ischemic Stroke: Preliminary In Vitro Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Small, W; Metzger, M F; Wilson, T S; Maitland, D J

    2004-09-23

    Due to the narrow (3-hour) treatment window for effective use of the thrombolytic drug recombinant tissue-type plasminogen activator (rt-PA), there is a need to develop alternative treatments for ischemic stroke. We are developing an intravascular device for mechanical thrombus removal using shape memory polymer (SMP). We propose to deliver the SMP microactuator in its secondary straight rod form (length = 4 cm, diameter = 350 {micro}m) through a catheter distal to the vascular occlusion. The microactuator, which is mounted on the end of an optical fiber, is then transformed into its primary corkscrew shape by laser heating (diode laser, {lambda} = 800 nm) above its soft phase glass transition temperature (T{sub gs} = 55 C). Once deployed, the microactuator is retracted and the captured thrombus is removed to restore blood flow. The SMP is doped with indocyanine green (ICG) dye to increase absorption of the laser light. Successful deployment of the microactuator depends on the optical properties of the ICG-doped SMP and the optical coupling efficiency of the interface between the optical fiber and the SMP. Spectrophotometry, thermal imaging, and computer simulation aided the initial design effort and continue to be useful tools for optimization of the dye concentration and laser power. Thermomechanical testing was performed to characterize the elastic modulus of the SMP. We have demonstrated laser-activation of the SMP microactuator in air at room temperature, suggesting this concept is a promising therapeutic alternative to rt-PA.

  11. Matrix-assisted laser desorption/ionization mass spectrometric analysis of poly(3,4-ethylenedioxythiophene) in solid-state dye-sensitized solar cells: comparison of in situ photoelectrochemical polymerization in aqueous micellar and organic media.

    Science.gov (United States)

    Zhang, Jinbao; Ellis, Hanna; Yang, Lei; Johansson, Erik M J; Boschloo, Gerrit; Vlachopoulos, Nick; Hagfeldt, Anders; Bergquist, Jonas; Shevchenko, Denys

    2015-04-07

    Solid-state dye-sensitized solar cells (sDSCs) are devoid of such issues as electrolyte evaporation or leakage and electrode corrosion, which are typical for traditional liquid electrolyte-based DSCs. Poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most popular and efficient p-type conducting polymers that are used in sDSCs as a solid-state hole-transporting material. The most convenient way to deposit this insoluble polymer into the dye-sensitized mesoporous working electrode is in situ photoelectrochemical polymerization. Apparently, the structure and the physicochemical properties of the generated conducting polymer, which determine the photovoltaic performance of the corresponding solar cell, can be significantly affected by the preparation conditions. Therefore, a simple and fast analytical method that can reveal information on polymer chain length, possible chemical modifications, and impurities is strongly required for the rapid development of efficient solar energy-converting devices. In this contribution, we applied matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) for the analysis of PEDOT directly on sDSCs. It was found that the PEDOT generated in aqueous micellar medium possesses relatively shorter polymeric chains than the PEDOT deposited from an organic medium. Furthermore, the micellar electrolyte promotes a transformation of one of the thiophene terminal units to thiophenone. The introduction of a carbonyl group into the PEDOT molecule impedes the growth of the polymer chain and reduces the conductivity of the final polymer film. Both the simplicity of sample preparation (only application of the organic matrix onto the solar cell is needed) and the rapidity of analysis hold the promise of making MALDI MS an essential tool for the physicochemical characterization of conducting polymer-based sDSCs.

  12. Synthesis and Absorption Characteristics of Two Infrared Cyanine Dyes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Two infrared dyes, 1,3,3,1', 3', 3'-hexamethylindotricarbocyanine iodide (A) and 1,3,3,1',3',3'-hexamethyl-11-chloro-10,12-propylenetricarbocyanine iodide (B), were synthesized and characterized by melting point, elemental analysis, IR, and 1H-NMR. Their electron absorption spectra, laser absorption characteristics and solubility were investigated. The results showed that A and B have maximum absorption peaks at around 748 nm and 774 nm, respectivey, which match well with the wavelength output of the near infrared laser diode. The dyes were found to have photoinduced fading during irradiation with the infrared laser, especially in the presence of oxygen. However, this procession can be greatly slowed by using a layer of poly(vinyl alcohol) to barricade the dyes from oxygen. The experiments also showed that the dyes were thermally stable but decayed under strong sunlight. Furthermore, they are easily dissolved in some common solvents.

  13. Dyeing of Polypropylene Fibers with Vat Dyes

    Institute of Scientific and Technical Information of China (English)

    LIU Hang; ETTERS J. Nolan; LEONAS Karen K

    2006-01-01

    Polypropylene fibers have been extensively used in a variety of products, including carpets and upholstery, due to their non-absorbency, good weather resistance, good resistance to microorganisms and so on. Because of their hydrophobic and highly crystalline nature, those well-established conventional dyeing processes are difficult to apply to unmodified polypropylene. Colors of polypropylene fibers are primarily obtained by mass coloration which has the disadvantages of limited number of colors available and difficulties in inventory control due to the rapidly changing color needs of the market. In this paper, the use of vat dyes to dye polypropylene fabrics is investigated. Seventeen vat dyes were screened and factors influencing uptake of dyes by polypropylene fabrics were studied.

  14. Sampling system for pulsed signals. Study of the radioactive lifetimes of excited 3{sup 2}P1/2 and 3{sup 2}P3/2 states of Na, excited by a tunable dye laser; Sistema de muestreo para senales pulsadas. Estudio de vidas medias de niveles 3{sup 2} P1/2 y 3{sup 2}P3/2 excitados por un laser de colorantes pulsado

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, P.; Campos, J.

    1979-07-01

    A system for sampling and averaging repetitive signals in the order of nanoseconds is discussed. The system uses as storage memory a multichannel analyzer operating in multi scaling mode. This instrument is employed for the measurement of atomic level lifetimes using a dye laser to excite the atoms and is applied to the study of lifetimes of the 3{sup 2}P1/2 and 3{sup 2}P3/2 states of sodium. (Author) 32 refs.

  15. Vbeam脉冲染料激光治疗皮肤葡萄酒色斑的疗效分析%Therapeutic effect of Vbeam pulsed dye laser in the treatment of port wine stains

    Institute of Scientific and Technical Information of China (English)

    王美水; 黄循镭; 黄祖根; 庄福连; 王彪; 熊舒原; 郑厚兵

    2008-01-01

    Objective To evaluate the clinical therapeutic effects of Vbeam 595 nm pulsed dye laser in114 cases of port wine stains.Methods 114 patients with port wine stains were treated with Vbeam 595 nm pulsed dye laser with 3~10 ms pulse width and 7mm spot size.The energy fluence used varied from 10 to 15 J/cm2.Dynamic cooling device(DCD)was used to protect epiderm,with DCD spray 30~40 ms and DCD delay 10~30 ms.The interval of therapy was 4~8 weeks.The results were graded on basis of cleaning and fading as follows:grade Ⅰ(>75%),gradeⅡ(50%to 74%),grade Ⅲ(25%to 49%),and grade Ⅳ(<25%).Results 114 patients completed the therapy.The number of treatments ranged from 1 to 10(mean 5.9).The results evaluated as grades Ⅰ,Ⅱ,Ⅲ and Ⅳ were 74 patients(64.9%),29 patients(25.4%),9 patients(7.9%)and 2 patients(1.8%),respectively.The therapeutic effect was analysed according to number of treatments.the ages of patients,site and color of the lesions.It was found that the therapeutic effect was prominent in patients of younger age,with pink lesions located on the neck and face.No recurrence and scar happened after 6 months to 2 years follow-up.Conclnsions Vbeam 595nm pulsed dye laser is a safe and effective method for the treatent of port wine stains,with less complications.%目的 评价595 nm Vbeam脉冲染料激光治疗皮肤葡萄酒色斑(Pint wine stains,PWS)的临床疗效.方法 共114例PWS患者接受595 nm Vbeam脉冲染料激光治疗,脉宽3~10 ms,光斑直径7mm,能量密度10-15 J/cm2,动态冷却喷射30~40 ms,间隔10~30 ms,治疗间隔4~8周.根据皮损消退,将疗效分为4级:Ⅰ级为>75%,Ⅱ级为50%~74%,Ⅲ级为25%~49%,Ⅳ级为<25%.结果 114例经过1~10次治疗(平均5.9次),取得很好临床效果,其中Ⅰ级74例(64.9%),Ⅱ级29例(25.4%),Ⅲ级9例(7.9%),Ⅳ级2例(1.8%).并分析治疗次数、年龄大小、发生部位、颜色特点和疗效的关系,年龄小、发生于颈面部位、粉红

  16. Physical and chemical investigations on natural dyes

    Science.gov (United States)

    Acquaviva, S.; D'Anna, E.; de Giorgi, M. L.; Della Patria, A.; Baraldi, P.

    2010-09-01

    Natural dyes have been used extensively in the past for many purposes, such us to colour fibers and to produce inks, watercolours and paints, but their use declined rapidly after the discovery of synthetic colours. Nowadays we witness a renewed interest, as natural dyes are neither toxic nor polluting. In this work, physical and chemical properties of four selected dyes, namely red (Madder), yellow (Weld and Turmeric) and blue (Woad) colours, produced by means of traditional techniques at the Museo dei Colori Naturali (Lamoli, Italy), have been investigated. The chromatic properties have been studied through the reflectance spectroscopy, a non-invasive technique for the characterisation of chromaticity. Reflection spectra both from powders and egg-yolk tempera models have been acquired to provide the typical features of the dyes in the UV-vis spectral range. Moreover, to assess the feasibility of laser cleaning procedures, tempera layers were investigated after irradiation with an excimer laser. Micro Raman spectroscopy, Scanning Electron Microscopy and Energy Dispersive X-Ray analyses have complemented the survey, returning compositional and morphological information as well. Efforts have been made to give scientific feedback to the production processes and to support the research activity in the restoration of the artworks where these dyes were employed.

  17. ELECTROMAGNETIC APPARATUS FOR MOVING A ROD

    Science.gov (United States)

    Young, J.N.

    1958-04-22

    An electromagnetic apparatus for moving a rod-like member in small steps in either direction is described. The invention has particular application in the reactor field where the reactor control rods must be moved only a small distance and where the use of mechanical couplings is impractical due to the high- pressure seals required. A neutron-absorbing rod is mounted in a housing with gripping uaits that engage the rod, and coils for magnetizing the gripping units to make them grip, shift, and release the rod are located outside the housing.

  18. Exploiting rod technology. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1990-06-01

    ROD development was proceeding apace until recent budgetary decisions caused funding support for ROD development to be drastically reduced. The funding which was originally provided by DARPA and the Balanced Technology Initiative (BTI) Office has been cut back to zero from $800K. To determine the aeroballistic coefficients of a candidate dart, ARDEC is currently supporting development out of its own 6.2 funds at about $100K. ARDEC has made slow progress toward achieving this end because of failures in the original dart during testing. It appears that the next dart design to be tested will diverge from the original concept visualized by DARPA and Science and Technology Associates (STA). STA, the design engineer, takes exception to these changes on the basis of inappropriate test conditions and insufficient testing. At this time, the full resolution of this issue will be difficult because of the current management structure, which separates the developer (ARDEC) from the designer (STA).

  19. Measuring stable isotopes of hydrogen and oxygen in ice by means of laser spectrometry : The Bolling transition in the Dye-3 (south Greenland) ice core

    NARCIS (Netherlands)

    Trigt, R. van; Meijer, H.A.J.; Sveinbjornsdottir, A.E.; Johnsen, S.J.; Kerstel, E.R.Th.

    2002-01-01

    We report on the first application of a new technique in ice-core research, based on direct absorption infrared laser spectrometry (LS), for measuring H-2 O-17 and O-18 isotope ratios. The data are used to calculate the deuterium excess d (defined as delta(2)H - 8delta(18)O) for a section of the

  20. Hair dye contact allergy

    DEFF Research Database (Denmark)

    Søsted, Heidi; Rastogi, Suresh Chandra; Andersen, Klaus Ejner

    2004-01-01

    Colouring of hair can cause severe allergic contact dermatitis. The most frequently reported hair dye allergens are p-phenylenediamine (PPD) and toluene-2,5-diamine, which are included in, respectively, the patch test standard series and the hairdressers series. The aim of the present study...... was to identify dye precursors and couplers in hair dyeing products causing clinical hair dye dermatitis and to compare the data with the contents of these compounds in a randomly selected set of similar products. The patient material comprised 9 cases of characteristic clinical allergic hair dye reaction, where...... exposure history and patch testing had identified a specific hair dye product as the cause of the reaction. The 9 products used by the patients were subjected to chemical analysis. 8 hair dye products contained toluene-2,5-diamine (0.18 to 0.98%). PPD (0.27%) was found in 1 product, and m-aminophenol (0...

  1. Ultrasonic dyeing of cellulose nanofibers.

    Science.gov (United States)

    Khatri, Muzamil; Ahmed, Farooq; Jatoi, Abdul Wahab; Mahar, Rasool Bux; Khatri, Zeeshan; Kim, Ick Soo

    2016-07-01

    Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing.

  2. Spectral and nonlinear studies of night blue dye

    Science.gov (United States)

    Sindhu Sukumaran, V.; Ramalingam, A.

    2006-12-01

    Solid-state dye-doped polymer is an attractive alternative to the conventional liquid dye solution. In this Letter the spectral characteristics and the nonlinear optical properties of the dye night blue are studied. The spectral characteristics of night blue dye doped poly(methylmethacrylate) modified with additive n-butyl acetate (nBA) are studied by recording its absorption and fluorescence spectra and the results are compared with the corresponding liquid mixture. The nonlinear refractive index of the dye in nBA and dye doped polymer film were measured using z-scan technique [S.-B., Mansoor, A.A. Said, T.-H. Wei, D.J. Hagan, E.W. Van Stryland, IEEE J. Quantum Electron. 26 (1990) 760], by exciting with He Ne laser. The results obtained are intercompared. Both the samples of dye night blue show a negative nonlinear refractive index. The origin of optical nonlinearity in the dye may be attributed due to laser-heating induced nonlinear effect.

  3. Lasers in medicine.

    Science.gov (United States)

    Viherkoski, E

    1990-01-01

    Since its discovery, the laser has been intensively investigated and used in medicine, first in ophthalmology then in ear, nose and throat surgery, gynaecology, neurosurgery etc. Development spans from the ruby and argon lasers in outpatient eye surgery to the carbon dioxide and Nd:YAG lasers in the operating theatres and further on to the PDT-dye lasers, excimer and solid state angioplasty lasers or flash lamp pumped "gallstone cracker" lasers. The CO2-Nd: YAG laser combination will be described as the state-of-art surgical laser. This simultaneous, coaxial and coherent combination laser offers a new possibility to cut and coagulate effectively at the same time. Operating times are shortened and bleeding volumes minimised. The CO2-Nd: YAG laser represents a new type of interaction between laser and tissue, laser enhanced tissue absorption, which will be described.

  4. Full 3D translational and rotational optical control of multiple rod-shaped bacteria.

    Science.gov (United States)

    Hörner, Florian; Woerdemann, Mike; Müller, Stephanie; Maier, Berenike; Denz, Cornelia

    2010-07-01

    The class of rod-shaped bacteria is an important example of non-spherical objects where defined alignment is desired for the observation of intracellular processes or studies of the flagella. However, all available methods for orientational control of rod-shaped bacteria are either limited with respect to the accessible rotational axes or feasible angles or restricted to one single bacterium. In this paper we demonstrate a scheme to orientate rod-shaped bacteria with holographic optical tweezers (HOT) in any direction. While these bacteria have a strong preference to align along the direction of the incident laser beam, our scheme provides for the first time full rotational control of multiple bacteria with respect to any arbitrary axis. In combination with the translational control HOT inherently provide, this enables full control of all three translational and the two important rotational degrees of freedom of multiple rod-shaped bacteria and allows one to arrange them in any desired configuration.

  5. Development of Welding and Instrumentation Technology for Nuclear Fuel Test Rod

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Chang Young; Ahn, Sung Ho; Heo, Sung Ho; Hong, Jin Tae; Kim, Ka Hye [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    It is necessary to develop various types of welding, instrumentation and helium gas filling techniques that can conduct TIG spot welding exactly at a pin-hole of the end-cap on the nuclear fuel rod to fill up helium gas. The welding process is one of the most important among the instrumentation processes of the nuclear fuel test rod. To manufacture the nuclear fuel test rod, a precision welding system needs to be fabricated to develop various welding technologies of the fuel test rod jointing the various sensors and end-caps on a fuel cladding tube, which is charged with fuel pellets and component parts. We therefore designed and fabricated an orbital TIG welding system and a laser welding system. This paper describes not only some experiment results from weld tests for the parts of a nuclear fuel test rod, but also the contents for the instrumentation process of the dummy fuel test rod installed with the C-type T. C. A dummy nuclear fuel test rod was successfully fabricated with the welding and instrumentation technologies acquired with various tests. In the test results, the round welding has shown a good weldability at both the orbital TIG welding system and the fiber laser welding system. The spot welding to fill up helium gas has shown a good welding performance at a welding current of 30A, welding time of 0.4 sec and gap of 1 mm in a helium gas atmosphere. The soundness of the nuclear fuel test rod sealed by a mechanical sealing method was confirmed by helium leak tests and microstructural analyses.

  6. Dermatological laser treatment. Dermatologisk laserbehandling

    Energy Technology Data Exchange (ETDEWEB)

    Moerk, N.J.; Austad, J. (Rikshospitalet, Oslo (Norway)); Helland, S. (Haukeland Sykehus, Bergen (Norway)); Thune, P. (Ullevaal Sykehus, Oslo (Norway)); Volden, G. (University and Regional Hospital, Trondheim (Norway)); Falk, E. (University and Regional Hospital, Tromsoe (Norway))

    1991-10-01

    The article reviews the different lasers used in dermatology. Special emphasis is placed on the treatment of naevus flammeus (''portwine stain'') where lasers are the treatment of choice. Argon laser and pulsed dye laser are the main lasers used in vascular skin diseases, and the article focuses on these two types. Copper-vapour laser, neodymium-YAG laser and CO{sub 2} laser are also presented. Information is provided about the availability of laser technology in the different health regions in Norway. 5 refs., 2 figs.

  7. High temperature control rod assembly

    Energy Technology Data Exchange (ETDEWEB)

    Vollman, Russell E. (Solana Beach, CA)

    1991-01-01

    A high temperature nuclear control rod assembly comprises a plurality of substantially cylindrical segments flexibly joined together in succession by ball joints. The segments are made of a high temperature graphite or carbon-carbon composite. The segment includes a hollow cylindrical sleeve which has an opening for receiving neutron-absorbing material in the form of pellets or compacted rings. The sleeve has a threaded sleeve bore and outer threaded surface. A cylindrical support post has a threaded shaft at one end which is threadably engaged with the sleeve bore to rigidly couple the support post to the sleeve. The other end of the post is formed with a ball portion. A hollow cylindrical collar has an inner threaded surface engageable with the outer threaded surface of the sleeve to rigidly couple the collar to the sleeve. the collar also has a socket portion which cooperates with the ball portion to flexibly connect segments together to form a ball and socket-type joint. In another embodiment, the segment comprises a support member which has a threaded shaft portion and a ball surface portion. The threaded shaft portion is engageable with an inner threaded surface of a ring for rigidly coupling the support member to the ring. The ring in turn has an outer surface at one end which is threadably engageably with a hollow cylindrical sleeve. The other end of the sleeve is formed with a socket portion for engagement with a ball portion of the support member. In yet another embodiment, a secondary rod is slidably inserted in a hollow channel through the center of the segment to provide additional strength. A method for controlling a nuclear reactor utilizing the control rod assembly is also included.

  8. Structural characteristics and biocompatibility of a new Nano-Ta-Ti alloy rod fabricated by laser melting technique%激光熔覆技术制备的纳米钽-钛合金棒结构特征及生物相容性

    Institute of Scientific and Technical Information of China (English)

    邹琳; 江建明; 杨勇; 陈长军; 瞿东滨

    2014-01-01

    目的:运用激光熔覆技术制备新型纳米钽-钛合金棒并研究其结构特征及生物相容性,为临床选用内固定提供依据。方法以纳米级钽粉(Ta,Tantalum)为原料,利用激光熔覆技术制备两侧具有对称纳米钽涂层的新型钛合金棒。SEM观察微观界面结构、测量孔隙直径并分析金相成分。采用MTT细胞毒性试验和ALP活性检测评价新型纳米钽-钛合金对MC3T3-E1细胞增殖和分化性能的影响。结果扫描电镜下观察到试样的Ta涂层表面呈粗糙多孔结构,钽粉颗粒间致密熔融,孔隙直径平均在200~300μm之间,加工过程前后成分一致;成分分析结果显示熔覆过程并未产生新的元素。两组材料皆可明显促进MC3T3-E1细胞增值,但新型纳米钽-钛合金性能更为优异,同时能够促进成骨细胞的骨化,差异具有统计学意义。结论激光熔覆技术可成功实现钽与医用钛合金的冶金结合,并使其拥有良好的表面结构和生物相容性。%Objective To evaluate the structural characteristics and biocompatibility of a novel nano-Ta-Ti alloy rod for its potential application in internal fixation. Methods Ta coating of a Ti alloy rod with nano-Ta (tantalum) powder was performed using laser melting with symmetrical grooves repleted with nano-Ta powder along the whole length. The microstructure of the cross section of Ta-Ti alloy rod, pore diameter and components of the coating were analyzed using scanning electron microscopy. The influence of this nano-Ta-Ti alloy on proliferation and differentiation of MC3T3-E1 cells was evaluated by MTT cytotoxicity test and ALP activity test. Results Under scanning electron microscope, the Ta-coating surface presented with a gross porous (200-300μm) structure with dense fusion between Ta particles, and no new element was produced after laser melting. Biocompatibility evaluation showed that Ti alloys with and without Ta coating both promoted

  9. Topological Mixing with Ghost Rods

    OpenAIRE

    2005-01-01

    Topological chaos relies on the periodic motion of obstacles in a two-dimensional flow in order to form nontrivial braids. This motion generates exponential stretching of material lines, and hence efficient mixing. Boyland et al. [P. L. Boyland, H. Aref, and M. A. Stremler, J. Fluid Mech. 403, 277 (2000)] have studied a specific periodic motion of rods that exhibits topological chaos in a viscous fluid. We show that it is possible to extend their work to cases where the motion of the stirring...

  10. Resonance Raman and UV-visible spectroscopy of black dyes on textiles.

    Science.gov (United States)

    Abbott, Laurence C; Batchelor, Stephen N; Smith, John R Lindsay; Moore, John N

    2010-10-10

    Resonance Raman and UV-visible diffuse reflectance spectra were recorded from samples of cotton, viscose, polyester, nylon, and acrylic textile swatches dyed black with one of seven single dyes, a mixture of two dyes, or one of seven mixtures of three dyes. The samples generally gave characteristic Raman spectra of the dyes, demonstrating that the technique is applicable for the forensic analysis of dyed black textiles. Survey studies of the widely used dye Reactive Black 5 show that essentially the same Raman spectrum is obtained on bulk sampling from the dye in solution, on viscose, on cotton at different uptakes, and on microscope sampling from the dye in cotton threads and single fibres. The effects of laser irradiation on the Raman bands and emission backgrounds from textile samples with and without dye are also reported. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  11. Laser Detection Of Latent Fingerprints: Tris(2,2'-Bipyridyl)Ruthenium(II) Chloride Hexahydrate As A Staining Dye For Time-Resolved Imaging

    Science.gov (United States)

    Menzel, E. R.

    1988-04-01

    The compound tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate is suitable for laser detection of latent fingerprints on difficult surfaces such as wood and masking tape, as well as surfaces such as polyethylene, metal, etc. The fingerprint treatment can Involve either dusting with powder blended with this compound or by solution staining. The compound displays a strong d-n phosphorescence with a lifetime of about 10-6 and is thus very well suited for time-resolved imaging to suppress background fluorescence.

  12. Reactor control rod timing system. [LMFBR

    Science.gov (United States)

    Wu, P.T.K.

    1980-03-18

    A fluid driven jet-edge whistle timing system is described for control rods of a nuclear reactor for producing real-time detection of the timing of each control rod in its scram operation. An important parameter in reactor safety, particularly for liquid metal fast breeder reactors (LMFBR), is the time deviation between the time the control rod is released and the time the rod actually reaches the down position. The whistle has a nearly pure tone signal with center frequency (above 100 kHz) far above the frequency band in which the energy of the background noise is concentrated. Each control rod can be fitted with a whistle with a different frequency so that there is no ambiguity in differentiating the signal from each control rod.

  13. The optimisation of the Multi-Atmospheric Ar:Xe Laser

    NARCIS (Netherlands)

    Gielkens, S.W.A.

    1998-01-01

    In 1960 the first successful demonstration of laser operation was achieved by Maiman in ruby [1], which is an example of a solid-state laser. Since then numerous other types of lasers have been constructed, like gas lasers, semiconductor lasers, dye lasers, chemical lasers and free-electron lasers

  14. Dyes as teratogens.

    Science.gov (United States)

    Sandor, S

    1992-01-01

    The main fats and problems of the role of dyes in prenatal pathology are reviewed. The first section deals with the practical aspects related to teratological screening of industrial dyes (including also the results obtained in this laboratory). In the second section, various aspects of azo-dye teratogenesis are largely discussed, including also the experimental contributions of this laboratory. Concluding remarks are made with respect to the importance and to the perspectives of this field of research.

  15. Thin-Film Evaporative Cooling for Side-Pumped Laser

    Science.gov (United States)

    Stewart, Brian K. (Inventor)

    2010-01-01

    A system and method are provided for cooling a crystal rod of a side-pumped laser. A transparent housing receives the crystal rod therethrough so that an annular gap is defined between the housing and the radial surface of the crystal rod. A fluid coolant is injected into the annular gap such the annular gap is partially filled with the fluid coolant while the radial surface of the crystal rod is wetted as a thin film all along the axial length thereof.

  16. Clinical experience of pulsed dye laser in the treatment of facial photoaging skin%脉冲染料激光治疗面部光老化皮肤的临床体会

    Institute of Scientific and Technical Information of China (English)

    袁金宝

    2014-01-01

    目的:研究并分析脉冲染料激光治疗面部光老化皮肤的临床效果。方法选择我院2013年1月到2013年8月收治的48例面部光老化皮肤患者作为研究对象,采用美国Cynosune公司的脉宽脉冲染料激光机进行治疗,具体的参数根据患者皮肤类型与年龄进行调整,根据患者治疗前后的毛细血管扩张度、皱纹多少、皮肤角化以及色素沉着情况评价治疗效果,并统计患者满意度。结果治疗效果显示,痊愈、显效、有效、无效例数分别为16、24、6、2,治疗有效率为83.3%。I型、II型与III型治疗有效率分别为100%、78.3%、25%,无患者出现瘢痕与色素沉着的不良反应,患者满意度为100%。结论脉冲燃料激光治疗法对于面部光老化皮肤患者可以起到良好的治疗效果,不良反应发生率低,该种治疗措施是值得在临床中进行推广和使用的。%Objective To study the clinical effect and analysis of pulsed dye laser in the treatment of facial photoaging skin. Methods 48 cases in our hospital from 2013 January to 2013 facial skin photoaging patients admitted in August as the research object, using the pulse width America Cynosune were treated with pulsed dye laser machine, specific parameters were adjusted according to patients with skin type and age, according to the capillary expansion before and after treatment in patients with tension, wrinkles, skin hyperkeratosis and how much pigmentation to evaluate the effect of treatment, patients’ satisfaction and statistics. Results the therapeutic effect of display, heal, effect, valid, invalid cases were 16, 24, 6, 2, the effective rate of treatment was 83.3%. II type and III type of I, the treatment efficiency were 100%, 78.3%, 25%, no adverse reactions in patients with scar and pigmentation, patient satisfaction was 100%. Conclusion for the patients with facial photoaging skin can play a good therapeutic effect of pulsed fuel laser therapy

  17. Automatic safety rod for reactors. [LMFBR

    Science.gov (United States)

    Germer, J.H.

    1982-03-23

    An automatic safety rod for a nuclear reactor containing neutron absorbing material and designed to be inserted into a reactor core after a loss-of-flow. Actuation is based upon either a sudden decrease in core pressure drop or the pressure drop decreases below a predetermined minimum value. The automatic control rod includes a pressure regulating device whereby a controlled decrease in operating pressure due to reduced coolant flow does not cause the rod to drop into the core.

  18. Laser emission of dye-doped liquid crystal evices under applying voltage%电场作用下染料掺杂液晶器件的激光辐射

    Institute of Scientific and Technical Information of China (English)

    岱钦; 乌日娜; 杨健; 徐送宁; 全薇

    2011-01-01

    通过在向列相液晶TEB30A中掺杂激光染料DCM和手性剂CB15制作了平面排列态液晶器件.采用Nd:YAG倍频532 nm波段激光作为泵浦光源,测量分析了平行于液晶器件表面方向的受激辐射光谱.当泵浦光较弱时,观察到了染料DCM较宽的荧光辐射谱;随着泵浦光的逐渐增强,辐射谱带逐渐变窄,辐射峰中心波长约为610 nm,最小半峰全宽(FWHM)为11 nm.观察了在器件玻璃基板上施加交流电场后激光辐射的变化情况,结果显示,当外加电压<9 V时,辐射强度随着电压的增大逐渐减弱;当外加电压>9 V,辐射强度迅速衰减,谱线变宽,显示了较好的电场控制特性.文章认为这种现象主要是由于电场作用下液晶分子取向发生变化所致.%A planar texture device was prepared by doping a laser dye (DCM) and a chiral compound (CB15) into a nematic liquid crystal TEB30A. By using a second harmonic Q-switched Nd: YAG pulsed laser (λ=532 nm) as pumping source, the emission spectrum of the device surface in the horizontal direction was measured and analyzed. It shows that a wide emission spectrum can be observed when the pump light is weak. With the increase of pump light, the stimulated emission spectrum is narrowed,and its center wavelength with a least Full Width of Half Maximum (FWHM)about 11 nm is at 610 nm. Moreover,by applying a AC voltage along the perpendicular direction to the surface of the device,the laser emission was also observed. When the applying voltage is less than 9 V,the lasing intensity is weakened with the increase of the voltage. When the applying voltage is greater than 9 V,the emission intensity is decreased sharply. These results can be attributed to the liquid crystal alignment changed on the applying electric field.

  19. WATERLESS DYEING [REVIEW

    Directory of Open Access Journals (Sweden)

    DEVRENT Nalan

    2015-05-01

    Full Text Available The textile industry is believed to be one of the biggest consumers of water. Water consumption and exhaustion in dyeing textile materials in conventional methods is an important environmental problem. The cost of waste water treatment will cause a prominent problem in the future as it does today. Increasing consideration of ecologic consequences of industrial processes as well as legislation enforcing the avoidance of environmental problems have caused a reorientation of thinking and promoted projects for replacement of conventional technologies. One of these new technologies is dyeing in supercritical fluids. Dyeing with supercritical carbon dioxide is a favourable concept considering the value of water as a natural resource and the cost of waste water treatment. This dyeing method offers many advantages over conventional aqueous dyeing: During this dyeing process no water is used, therefore there is no waste water problem, no other chemicals are required; the carbon dioxide can be recycled; the dystuff which is not adsorbed on the substrate can be collected and reused; The necessary energy consumption in this process is relatively lower than is needed to heat water in conventional methods of dyeing. Due to unnecessary of drying process, it helps to save both energy and time; and dyeing cycle is shorter compared with traditional methods. In addition carbon dioxide is non-toxic and non-flammable. Supercritical fluid, supercritical dyeing, disperse dyestuffs, solid-fluid equilibrium

  20. Acoustic loading effects on oscillating rod bundles

    Energy Technology Data Exchange (ETDEWEB)

    Lin, W.H.

    1980-01-01

    An analytical study of the interaction between an infinite acoustic medium and a cluster of circular rods is described. The acoustic field due to oscillating rods and the acoustic loading on the rods are first solved in a closed form. The acoustic loading is then used as a forcing function for rod responses, and the acousto-elastic couplings are solved simultaneously. Numerical examples are presented for several cases to illustrate the effects of various system parameters on the acoustic reaction force coefficients. The effect of the acoustic loading on the coupled eigenfrequencies are discussed.

  1. PVA with nopal dye as holographic recording material

    Science.gov (United States)

    Toxqui-López, S.; Olivares-Pérez, A.; Fuentes-Tapia, I.; Pinto-Iguanero, B.

    2011-09-01

    Cactus nopal dye is introduced into a polyvinyl alcohol matrix achieving a like brown appearance thick film, such that they can be used as a recording medium. This dye material provides excellent property as photosensitizer, i.e., easy handling, low cost and can be used in real time holographic recording applications. The experimental results show the diffraction efficiencies obtained by recording grating patterns induced by a He-Cd laser (442nm). For the samples, a thick film of polyvinyl alcohol and dye from cactus nopal was deposited by the gravity technique on a glass substrate. This mixture dries to form a photosensitive emulsion.

  2. [The use of lasers in dermatology].

    Science.gov (United States)

    Lecocq, C; Pirard, D; del Marmol, V; Berlingin, E

    2013-01-01

    Albert Einstein is undoubtedly the father of lasers. But it is not until 1964 that the first dermatological lasers were introduced. The Nd-YAG laser, the CO2 laser were developed by Kumar Patel. In a 40 year period lasers not only were diversified but have also become safer and miniaturized. This article hopes to strengthen general practionners' and specialist's knowledge of the different categories of available lasers. The most frequently used ones are ablative lasers (CO2-Erbium), vascular lasers (Nd-YAG, KTP, pulsed dye laser) and the pigment lasers (Q-Switched Nd-YAG, Alexandrite). A description of these lasers and their indications in dermatology will be discussed.

  3. Anaerobic azo dye reduction

    NARCIS (Netherlands)

    Zee, van der F.P.

    2002-01-01

    Azo dyes, aromatic moieties linked together by azo (-N=N-) chromophores, represent the largest class of dyes used in textile-processing and other industries. The release of these compounds into the environment is undesirable, not only because of their colour, but also because many azo

  4. Anaerobic azo dye reduction

    NARCIS (Netherlands)

    Zee, van der F.P.

    2002-01-01

    Azo dyes, aromatic moieties linked together by azo (-N=N-) chromophores, represent the largest class of dyes used in textile-processing and other industries. The release of these compounds into the environment is undesirable, not only because of their colour, but also b

  5. Hydrodynamic behavior of a bare rod bundle. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Bartzis, J.G.; Todreas, N.E.

    1977-06-01

    The temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers.

  6. Viscoelasticity of suspensions of long, rigid rods

    NARCIS (Netherlands)

    Dhont, Jan K.G.; Briels, W.J.

    2003-01-01

    A microscopic theory for the viscoelastic behaviour of suspensions of rigid rods with excluded volume interactions is presented, which is valid in the asymptotic limit of very long and thin rods. Stresses arising from translational and rotational Brownian motion and direct interactions are calculate

  7. Study of the rod style SFRFQ structure

    CERN Document Server

    Yan Xue Qing; Chen J

    2002-01-01

    There is a problem about upper limit of energy in the RFQ structure, although it is a wonderful low-energy-suited high current accelerating structure. After proposing an improved rod style SFRFQ structure without reversed field, the author studies its energy gain and transverse motion. The rod style SFRFQ structure is roughly compared with diaphragm SFRFQ structure

  8. Measurement of radical-species concentrations and polycyclic aromatic hydrocarbons in flames by fluorescence and absorption using a tunable dye laser. Progress report, March 1, 1980-February 28, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Lucht, R.P.; Sweeney, D.W.; Laurendeau, N.M.

    1981-03-01

    A theoretical and experimental investigation of OH saturated fluorescence is described. The goal of the research is to develop a saturated fluorescence technique which will yield accurate molecular number densities over a wide range of flame pressure, temperature, and composition. Experimentally, OH is excited by a ten nanosecond pulse from a Nd:YAG-pumped dye laser tuned to an isolated rotational transition in the (0,0) band of the A/sup 2/..sigma../sup +/-X/sup 2/ pi electronic system. The resulting fluorescence signal is resolved both spectrally and temporally. Total OH number densities are calculated by collecting fluorescence from the directly excited upper rotational level, and using the balanced cross-rate model to analyze the experimental data. Fluorescence measurements of OH number density agree to within a factor of three with the results of independent OH absorption measurements. Significantly, the ratio of the fluorescence signal to the number density measured by absorption is nearly the same in 30, 100 and 250 torr H/sub 2//O/sub 2//N/sub 2/ flat flames, demonstrating the insensitivity of the saturated fluorescence signal to the quenching environment of the radical. Collisional transfer in excited OH is studied by recording the time development of OH fluorescence spectrum. The experimental spectra are compared with the results of time-dependent computer modeling. By varying rotational transfer rates until the calculated and experimental spectra agree, rotational transfer cross sections can be calculated. The signal processing system was thoroughly checked by comparing the photomultiplier output to that of a fast photodiode, and by comparing single pulse Rayleigh scattering and fluorescence traces with sampling oscilloscope traces.

  9. Nrl is required for rod photoreceptor development.

    Science.gov (United States)

    Mears, A J; Kondo, M; Swain, P K; Takada, Y; Bush, R A; Saunders, T L; Sieving, P A; Swaroop, A

    2001-12-01

    The protein neural retina leucine zipper (Nrl) is a basic motif-leucine zipper transcription factor that is preferentially expressed in rod photoreceptors. It acts synergistically with Crx to regulate rhodopsin transcription. Missense mutations in human NRL have been associated with autosomal dominant retinitis pigmentosa. Here we report that deletion of Nrl in mice results in the complete loss of rod function and super-normal cone function, mediated by S cones. The photoreceptors in the Nrl-/- retina have cone-like nuclear morphology and short, sparse outer segments with abnormal disks. Analysis of retinal gene expression confirms the apparent functional transformation of rods into S cones in the Nrl-/- retina. On the basis of these findings, we postulate that Nrl acts as a 'molecular switch' during rod-cell development by directly modulating rod-specific genes while simultaneously inhibiting the S-cone pathway through the activation of Nr2e3.

  10. Treatment of nail psoriasis with Pulse Dye Laser plus calcipotriol betametasona gel vs. Nd:YAG plus calcipotriol betamethasone gel: An intrapatient left-to-right controlled study.

    Science.gov (United States)

    Arango-Duque, L C; Roncero-Riesco, M; Usero Bárcena, T; Palacios Álvarez, I; Fernández López, E

    2017-03-01

    Treatment of nail psoriasis remains a challenging and often disappointing situation. To compare the efficacy, adverse reactions and tolerability of treatment of nail psoriasis with PDL vs. Nd:YAG, in association with betametasona calcipotriol gel. An open, prospective intrapatient left-to-right study was designed. The right hand of each patient received treatment with PDL and the left hand with Nd:YAG. Betamethasone calcipotriol gel was applied once a day during the first week after each laser session. A total of four sessions were administered. The clinical efficacy was evaluated according to the NAPSI score. All patients showed improvement in nail bed and nail matrix psoriasis. The global NAPSI mean declined in 15.46 (p<0.000). There was neither statistical difference between the reduction in nail bed and matrix NAPSI nor in the treatment with PDL vs. Nd:YAG. The administration of Nd:YAG was more painful. No serious adverse effects were documented. No random assignment and the small number of patients. PDL and Nd:YAG have proven to be an effective treatment for nail psoriasis with no serious adverse effect. No statistically significant difference was found between the two treatments. Copyright © 2016. Publicado por Elsevier España, S.L.U.

  11. Phase behavior and structure formation of hairy-rod supramolecules

    NARCIS (Netherlands)

    Subbotin, A; Stepanyan, R; Knaapila, M; Ikkala, O; ten Brinke, G

    2003-01-01

    Phase behavior and microstructure formation of rod and coil molecules, which can associate to form hairy-rod polymeric supramolecules, are addressed theoretically. Association induces considerable compatibility enhancement between the rod and coil molecules and various microscopically ordered struct

  12. HCN1 Channels Enhance Rod System Responsivity in the Retina under Conditions of Light Exposure.

    Directory of Open Access Journals (Sweden)

    Vithiyanjali Sothilingam

    Full Text Available Vision originates in rods and cones at the outer retina. Already at these early stages, diverse processing schemes shape and enhance image information to permit perception over a wide range of lighting conditions. In this work, we address the role of hyperpolarization-activated and cyclic nucleotide-gated channels 1 (HCN1 in rod photoreceptors for the enhancement of rod system responsivity under conditions of light exposure.To isolate HCN1 channel actions in rod system responses, we generated double mutant mice by crossbreeding Hcn1-/- mice with Cnga3-/- mice in which cones are non-functional. Retinal function in the resulting Hcn1-/- Cnga3-/- animals was followed by means of electroretinography (ERG up to the age of four month. Retinal imaging via scanning laser ophthalmoscopy (SLO and optical coherence tomography (OCT was also performed to exclude potential morphological alterations.This study on Hcn1-/- Cnga3-/- mutant mice complements our previous work on HCN1 channel function in the retina. We show here in a functional rod-only setting that rod responses following bright light exposure terminate without the counteraction of HCN channels much later than normal. The resulting sustained signal elevation does saturate the retinal network due to an intensity-dependent reduction in the dynamic range. In addition, the lack of rapid adaptational feedback modulation of rod photoreceptor output via HCN1 in this double mutant limits the ability to follow repetitive (flicker stimuli, particularly under mesopic conditions.This work corroborates the hypothesis that, in the absence of HCN1-mediated feedback, the amplitude of rod signals remains at high levels for a prolonged period of time, leading to saturation of the retinal pathways. Our results demonstrate the importance of HCN1 channels for regular vision.

  13. Determining Compatibilities of Reactive Dyes in Pad Dyeing

    Institute of Scientific and Technical Information of China (English)

    屠天民

    2001-01-01

    Compatibilities of reactive dyes were conventionally shown by exhausting curves. But the change of proportion of dyes in padding dyebath was difficult for pad dyeing to be described by these curves. In this paper, a kind of simulation of pad dyeing process was used to determine dyestuff compatibility in pad dyeing for ramie and linen fabrics. Seven reactive dyes were divided into three groups and tested., The group with Cibacron Yellow C - 2R, Red C - R, and Blue C - R showed very good compatibility both for ramie and linen,and the other two groups of dyes gave out correspondingly low compatibilities in the pad dyeing tests. The results of the method for determining the compatibility of dyes displayed good consistency with the actul pad dyeing process.

  14. Eulerian Formulation of Spatially Constrained Elastic Rods

    Science.gov (United States)

    Huynen, Alexandre

    Slender elastic rods are ubiquitous in nature and technology. For a vast majority of applications, the rod deflection is restricted by an external constraint and a significant part of the elastic body is in contact with a stiff constraining surface. The research work presented in this doctoral dissertation formulates a computational model for the solution of elastic rods constrained inside or around frictionless tube-like surfaces. The segmentation strategy adopted to cope with this complex class of problems consists in sequencing the global problem into, comparatively simpler, elementary problems either in continuous contact with the constraint or contact-free between their extremities. Within the conventional Lagrangian formulation of elastic rods, this approach is however associated with two major drawbacks. First, the boundary conditions specifying the locations of the rod centerline at both extremities of each elementary problem lead to the establishment of isoperimetric constraints, i.e., integral constraints on the unknown length of the rod. Second, the assessment of the unilateral contact condition requires, in principle, the comparison of two curves parametrized by distinct curvilinear coordinates, viz. the rod centerline and the constraint axis. Both conspire to burden the computations associated with the method. To streamline the solution along the elementary problems and rationalize the assessment of the unilateral contact condition, the rod governing equations are reformulated within the Eulerian framework of the constraint. The methodical exploration of both types of elementary problems leads to specific formulations of the rod governing equations that stress the profound connection between the mechanics of the rod and the geometry of the constraint surface. The proposed Eulerian reformulation, which restates the rod local equilibrium in terms of the curvilinear coordinate associated with the constraint axis, describes the rod deformed configuration

  15. Lasers in Ophthalmology

    Institute of Scientific and Technical Information of China (English)

    1992-01-01

    In recent years,lasers have entered every fieldof medicine and especially so in ophthalmol-ogy.The scientific basis of lasers in ophthal-mology is based on three mechanisms:1.Photothermal effectLasers:argon,krypton,dye and diodeA thermal effect is generated when laserenergy is absorbed by pigment leading to in-creased vibration and therefore heat content.A

  16. Unsymmetrical Heptamethine Dyes for NIR Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Thomas Geiger

    2014-01-01

    Full Text Available Seven unsymmetrical heptamethine dyes with carboxylic acid functionality were synthesized and characterized. These near-infrared dyes exhibit outstanding photophysical properties depending on their heterocyclic moieties and molecular structure. As proof of principle, the dyes were used as photosensitizers in dye-sensitized solar cells. Using the most promising dye, an overall conversion efficiency of 1.22% and an almost colorless solar cell were achieved.

  17. Dyeing of Polyester with Disperse Dyes: Part 2. Synthesis and Dyeing Characteristics of Some Azo Disperse Dyes for Polyester Fabrics

    Directory of Open Access Journals (Sweden)

    Alya M. Al-Etaibi

    2016-06-01

    Full Text Available The goal of this study was to utilize carrier for accelerating the rate of dyeing not only to enhance dyeing of polyester fabrics dyed with disperse dyes 3a,b, but also to save energy. Both the color strength expressed as dye uptake and the fastness properties of the dyed fabrics were evaluated.

  18. Fong's: Saving Water in Dyeing

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ In an effort to save the precious water resource and reduce the environmental impact, Fong's Industries Group along with its member companies, namely "Fong's National", "THEN", "Goller" and "Fong's Water Technology" provide an ecological dyeing solution to reduce the water consumption drastically through their innovative technologies covering the processes from yarn dyeing to piece dyeing and recycling of discharge after dyeing and finishing.

  19. Morphoelastic rods Part II: Growing birods

    Science.gov (United States)

    Lessinnes, Thomas; Moulton, Derek E.; Goriely, Alain

    2017-03-01

    The general problem of determining the shape and response of two attached growing elastic Kirchhoff rods is considered. A description of the kinematics of the individual interacting rods is introduced. Each rod has a given intrinsic shape and constitutive laws, and a map associating points on the two rods is defined. The resulting filamentary structure, a growing birod, can be seen as a new filamentary structure. This kinematic description is used to derive the general equilibrium equations for the shape of the rods under loads, or equivalently, for the new birod. It is shown that, in general, the birod is not simply a Kirchhoff rod but rather, due to the internal constraints, new effects can appear. The two-dimensional restriction is then considered explicitly and the limit for small deformation is shown to be equivalent to the classic Timsohenko bi-metallic strip problem. A number of examples and applications are presented. In particular, the problem of two attached rods with intrinsic helical shape and uniform growth is computed in detail and a host of new interesting solutions and bifurcations are observed.

  20. Granular materials interacting with thin flexible rods

    Science.gov (United States)

    Neto, Alfredo Gay; Campello, Eduardo M. B.

    2017-04-01

    In this work, we develop a computational model for the simulation of problems wherein granular materials interact with thin flexible rods. We treat granular materials as a collection of spherical particles following a discrete element method (DEM) approach, while flexible rods are described by a large deformation finite element (FEM) rod formulation. Grain-to-grain, grain-to-rod, and rod-to-rod contacts are fully permitted and resolved. A simple and efficient strategy is proposed for coupling the motion of the two types (discrete and continuum) of materials within an iterative time-stepping solution scheme. Implementation details are shown and discussed. Validity and applicability of the model are assessed by means of a few numerical examples. We believe that robust, efficiently coupled DEM-FEM schemes can be a useful tool to the simulation of problems wherein granular materials interact with thin flexible rods, such as (but not limited to) bombardment of grains on beam structures, flow of granular materials over surfaces covered by threads of hair in many biological processes, flow of grains through filters and strainers in various industrial segregation processes, and many others.

  1. Magnetically controlled growing rods for scoliosis surgery.

    Science.gov (United States)

    Metkar, Umesh; Kurra, Swamy; Quinzi, David; Albanese, Stephen; Lavelle, William F

    2017-02-01

    Early onset scoliosis can be both a disfiguring as well as a life threatening condition. When more conservative treatments fail, pediatric spinal surgeons are forced to consider operative interventions. Traditionally, these interventions have involved the insertion of a variety of implants into the patient with a limited number of anchor points controlling the spine. In the past, these pediatric patients have had multiple surgeries for elective lengthening of these devices to facilitate their growth while attempting to control the scoliosis. These patients often experience a physical and emotional toll from their multiple repeated surgeries. Growing spine techniques have also had a noted high complication rate due to implant dislodgement and infections. Recently, the development of non-invasively, self-lengthening growing rods has occurred. These devices have the potential to allow for the devices to be lengthened magnetically in a conscious patient in the surgeon's office. Areas covered: This review summarized previously published articles in the English literature using a key word search in PubMed for: 'magnetically controlled growing rods', 'Magec rods', 'magnetic growing rods' and 'growing rods'. Expert commentary: Magnetically controlled growing rods have an advantage over growing rods in lengthening the growing spine in the absence of repetitive surgeries.

  2. Control Rod Malfunction at the NRAD Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Thomas L. Maddock

    2010-05-01

    The neutron Radiography Reactor (NRAD) is a training, research, and isotope (TRIGA) reactor located at the INL. The reactor is normally shut down by the insertion of three control rods that drop into the core when power is removed from electromagnets. During a routine shutdown, indicator lights on the console showed that one of the control rods was not inserted. It was initially thought that the indicator lights were in error because of a limit switch that was out of adjustment. Through further testing, it was determined that the control rod did not drop when the scram switch was initially pressed. The control rod anomaly led to a six month shutdown of the reactor and an in depth investigation of the reactor protective system. The investigation looked into: scram switch operation, console modifications, and control rod drive mechanisms. A number of latent issues were discovered and corrected during the investigation. The cause of the control rod malfunction was found to be a buildup of corrosion in the control rod drive mechanism. The investigation resulted in modifications to equipment, changes to both operation and maintenance procedures, and additional training. No reoccurrences of the problem have been observed since corrective actions were implemented.

  3. Estimation of irradiated control rod worth

    Energy Technology Data Exchange (ETDEWEB)

    Varvayanni, M., E-mail: melina@ipta.demokritos.g [NCSR ' DEMOKRITOS' , PO Box 60228, 15310 Aghia Paraskevi (Greece); Catsaros, N. [NCSR ' DEMOKRITOS' , PO Box 60228, 15310 Aghia Paraskevi (Greece); Antonopoulos-Domis, M. [School of Electrical and Computer Engineering, Aristotle University of Thessaloniki, Thessaloniki (Greece)

    2009-11-15

    When depleted control rods are planned to be used in new core configurations, their worth has to be accurately predicted in order to deduce key design and safety parameters such as the available shutdown margin. In this work a methodology is suggested for the derivation of the distributed absorbing capacity of a depleted rod, useful in the case that the level of detail that is known about the irradiation history of the control rod does not allow an accurate calculation of the absorber's burnup. The suggested methodology is based on measurements of the rod's worth carried out in the former core configuration and on corresponding calculations based on the original (before first irradiation) absorber concentration. The methodology is formulated for the general case of the multi-group theory; it is successfully tested for the one-group approximation, for a depleted control rod of the Greek Research Reactor, containing five neutron absorbers. The computations reproduce satisfactorily the irradiated rod worth measurements, practically eliminating the discrepancy of the total rod worth, compared to the computations based on the nominal absorber densities.

  4. Granular materials interacting with thin flexible rods

    Science.gov (United States)

    Neto, Alfredo Gay; Campello, Eduardo M. B.

    2016-01-01

    In this work, we develop a computational model for the simulation of problems wherein granular materials interact with thin flexible rods. We treat granular materials as a collection of spherical particles following a discrete element method (DEM) approach, while flexible rods are described by a large deformation finite element (FEM) rod formulation. Grain-to-grain, grain-to-rod, and rod-to-rod contacts are fully permitted and resolved. A simple and efficient strategy is proposed for coupling the motion of the two types (discrete and continuum) of materials within an iterative time-stepping solution scheme. Implementation details are shown and discussed. Validity and applicability of the model are assessed by means of a few numerical examples. We believe that robust, efficiently coupled DEM-FEM schemes can be a useful tool to the simulation of problems wherein granular materials interact with thin flexible rods, such as (but not limited to) bombardment of grains on beam structures, flow of granular materials over surfaces covered by threads of hair in many biological processes, flow of grains through filters and strainers in various industrial segregation processes, and many others.

  5. Recent Advances in the Study of Bipolar/Rod-Shaped Microglia and their Roles in Neurodegeneration.

    Science.gov (United States)

    Au, Ngan Pan Bennett; Ma, Chi Him Eddie

    2017-01-01

    Microglia are the resident immune cells of the central nervous system (CNS) and they contribute to primary inflammatory responses following CNS injuries. The morphology of microglia is closely associated with their functional activities. Most previous research efforts have attempted to delineate the role of ramified and amoeboid microglia in the pathogenesis of neurodegenerative diseases. In addition to ramified and amoeboid microglia, bipolar/rod-shaped microglia were first described by Franz Nissl in 1899 and their presence in the brain was closely associated with the pathology of infectious diseases and sleeping disorders. However, studies relating to bipolar/rod-shaped microglia are very limited, largely due to the lack of appropriate in vitro and in vivo experimental models. Recent studies have reported the formation of bipolar/rod-shaped microglia trains in in vivo models of CNS injury, including diffuse brain injury, focal transient ischemia, optic nerve transection and laser-induced ocular hypertension (OHT). These bipolar/rod-shaped microglia formed end-to-end alignments in close proximity to the adjacent injured axons, but they showed no interactions with blood vessels or other types of glial cell. Recent studies have also reported on a highly reproducible in vitro culture model system to enrich bipolar/rod-shaped microglia that acts as a powerful tool with which to characterize this form of microglia. The molecular aspects of bipolar/rod-shaped microglia are of great interest in the field of CNS repair. This review article focuses on studies relating to the morphology and transformation of microglia into the bipolar/rod-shaped form, along with the differential gene expression and spatial distribution of bipolar/rod-shaped microglia in normal and pathological CNSs. The spatial arrangement of bipolar/rod-shaped microglia is crucial in the reorganization and remodeling of neuronal and synaptic circuitry following CNS injuries. Finally, we discuss the

  6. Clean Photothermal Heating and Controlled Release from Near-Infrared Dye Doped Nanoparticles without Oxygen Photosensitization.

    Science.gov (United States)

    Guha, Samit; Shaw, Scott K; Spence, Graeme T; Roland, Felicia M; Smith, Bradley D

    2015-07-21

    The photothermal heating and release properties of biocompatible organic nanoparticles, doped with a near-infrared croconaine (Croc) dye, were compared with analogous nanoparticles doped with the common near-infrared dyes ICG and IR780. Separate formulations of lipid-polymer hybrid nanoparticles and liposomes, each containing Croc dye, absorbed strongly at 808 nm and generated clean laser-induced heating (no production of (1)O2 and no photobleaching of the dye). In contrast, laser-induced heating of nanoparticles containing ICG or IR780 produced reactive (1)O2, leading to bleaching of the dye and also decomposition of coencapsulated payload such as the drug doxorubicin. Croc dye was especially useful as a photothermal agent for laser-controlled release of chemically sensitive payload from nanoparticles. Solution state experiments demonstrated repetitive fractional release of water-soluble fluorescent dye from the interior of thermosensitive liposomes. Additional experiments used a focused laser beam to control leakage from immobilized liposomes with very high spatial and temporal precision. The results indicate that fractional photothermal leakage from nanoparticles doped with Croc dye is a promising method for a range of controlled release applications.

  7. Tipping time of a quantum rod

    Energy Technology Data Exchange (ETDEWEB)

    Parrikar, Onkar [Birla Institute of Technology and Science-Pilani, Goa campus, Zuarinagar, Goa 4032726 (India)], E-mail: onkarsp@gmail.com

    2010-03-15

    The behaviour of a quantum rod, pivoted at its lower end on an impenetrable floor and restricted to moving in the vertical plane under the gravitational potential, is studied analytically under the approximation that the rod is initially localized to a 'small-enough' neighbourhood around the point of classical unstable equilibrium. It is shown that the rod evolves out of this neighbourhood. The time required for this to happen, i.e. the tipping time, is calculated using the semi-classical path integral. It is shown that equilibrium is recovered in the classical limit, and that our calculations are consistent with the uncertainty principle.

  8. High temperature control rod assembly

    Energy Technology Data Exchange (ETDEWEB)

    Vollman, R.E.

    1991-12-24

    This patent describes a control rod assembly for use in nuclear reactor control. It comprises segments, each the segment being made of a graphite composite material, each the segment having a chamber for containing neutron-absorbing material, wherein the chamber compromises a hollow cylindrical sleeve having a first end formed with an opening for receiving the neutron-absorbing material, and having a second end formed with a sleeve bore and an outer sleeve surface; a cylindrical weight-bearing support post positioned substantially centrally of the sleeve, the support post having a first end formed as a ball surface portion and a second end formed as a ball surface portion and a second end formed as a shaft, the shaft being engageable with the sleeve bore for rigidly coupling the support post axially within the hollow sleeve, a hollow cylindrical collar having a socket lip portion correspondingly shaped to receive the ball surface portion of an adjacent support post, and having an inner surface for engaging the outer sleeve surface on the second end of the sleeve to rigidly couple the collar to the sleeve.

  9. Extraction of dye

    African Journals Online (AJOL)

    ... Uganda is a home of thousands of largely unknown and undocumented plants. ... Dyes of natural origins are great for color appreciation as any variation in the ... Asteraceae characterized by bitter leaves, traditionally used for treating fever.

  10. Electrospun dye-doped fiber networks: lasing emission from randomly distributed cavities

    DEFF Research Database (Denmark)

    Krammer, Sarah; Vannahme, Christoph; Smith, Cameron

    2015-01-01

    Dye-doped polymer fiber networks fabricated with electrospinning exhibit comb-like laser emission. We identify randomly distributed ring resonators being responsible for lasing emission by making use of spatially resolved spectroscopy. Numerical simulations confirm this result quantitatively....

  11. Compact Dielectric-Rod White-Light Delay Lines

    Science.gov (United States)

    Maleki, Lute; Matsko, Andrey; Savchenkov, Anatoliy; Strekalov, Dmitry

    2008-01-01

    Optical delay lines of a proposed type would be made from rods of such dielectric materials as calcium fluoride, fused silica, or sapphire. These would offer advantages over prior optical delay lines, as summarized below. Optical delay lines are key components of opto-electronic microwave oscillators, narrow-band opto-electronic microwave filters, evanescent-field optical biochemical detectors, and some Fourier-Transform spectrum analyzers. Heretofore, optical delay lines used in such applications have been of two types: resonators and coiled long optical fibers, both of which have disadvantages: Resonators are compact, but excitation must be provided by narrow-band lasers. Wide-band (including noisy) laser light cannot be coupled efficiently to narrow-band resonators. When light is coupled into a narrowband resonator from a source of reasonably high power, a significant amount of optical energy circulates within the resonator, causing nonlinear loss and significant noise. Typically, a coil-type optical delay line is made of fused-silica fiber, which exhibits fundamental loss. To overcome the limit imposed by the optical loss in fused silica, it would be necessary to use fibers having crystalline cores. Although space is saved by winding fibers into coils, fiber-coil delay lines are still inconveniently bulky. The proposed compact dielectric-rod delay lines would exploit the special class of non-diffracting light beams that are denoted Bessel beams because their amplitudes are proportional to Bessel functions of the radii from their central axes. High-order Bessel beams can have large values of angular momentum. They can be generated with the help of whispering-gallery-mode optical resonators, as described, for example, in "Simplified Generation of High-Angular-Momentum Light Beams" (NPO-42965) NASA Tech Briefs, Vol. 31, No. 3 (March 2007), page 8a. In a delay line according to the proposal, the dielectric rod would be dimensioned to function as a multimode

  12. Synthesis of Cone-Shaped Colloids from Rod-Like Silica Colloids with a Gradient in the Etching Rate.

    Science.gov (United States)

    Hagemans, Fabian; van der Wee, Ernest B; van Blaaderen, Alfons; Imhof, Arnout

    2016-04-26

    We present the synthesis of monodisperse cone-shaped silica colloids and their fluorescent labeling. Rod-like silica colloids prepared by ammonia-catalyzed hydrolysis and condensation of tetraethyl orthosilicate in water droplets containing polyvinylpyrrolidone cross-linked by citrate ions in pentanol were found to transform into cone-shaped particles upon mild etching by NaOH in water. The diameter and length of the resulting particles were determined by those of the initial rod-like silica colloids. The mechanism responsible for the cone-shape involves silica etching taking place with a varying rate along the length of the particle. Our experiments thus also lead to new insights into the variation of the local particle structure and composition. These are found to vary gradually along the length of the rod, as a result of the way the rod grows out of a water droplet that keeps itself attached to the flat end of the bullet-shaped particles. Subtle differences in composition and structure could also be resolved by high-resolution stimulated emission depletion confocal microscopy on fluorescently labeled particles. The incorporation of a fluorescent dye chemically attached to an amine-based silane coupling agent resulted in a distribution of fluorophores mainly on the outside of the rod-shaped particles. In contrast, incorporation of the silane coupling agent alone resulted in a homogeneous distribution. Additionally, we show that etching rods, where a silane coupling agent alone was incorporated and subsequently coupled to a fluorescent dye, resulted in fluorescent silica cones, the orientation of which can be discerned using super-resolution confocal microscopy.

  13. Impact of AD995 alumina rods

    Energy Technology Data Exchange (ETDEWEB)

    Chhabildas, L.C.; Furnish, M.D.; Reinhart, W.D. [Sandia National Labs., Albuquerque, NM (United States); Grady, D.E. [Applied Research Associates, Inc., Albuquerque, NM (United States)

    1997-10-01

    Gas guns and velocity interferometric techniques have been used to determine the loading behavior of an AD995 alumina rod 19 mm in diameter by 75 mm and 150 mm long, respectively. Graded-density materials were used to impact both bare and sleeved alumina rods while the velocity interferometer was used to monitor the axial-velocity of the free end of the rods. Results of these experiments demonstrate that (1) a time-dependent stress pulse generated during impact allows an efficient transition from the initial uniaxial strain loading to a uniaxial stress state as the stress pulse propagates through the rod, and (2) the intermediate loading rates obtained in this configuration lie between split Hopkinson bar and shock-loading techniques.

  14. Computer simulation of rod-sphere mixtures

    CERN Document Server

    Antypov, D

    2003-01-01

    Results are presented from a series of simulations undertaken to investigate the effect of adding small spherical particles to a fluid of rods which would otherwise represent a liquid crystalline (LC) substance. Firstly, a bulk mixture of Hard Gaussian Overlap particles with an aspect ratio of 3:1 and hard spheres with diameters equal to the breadth of the rods is simulated at various sphere concentrations. Both mixing-demixing and isotropic-nematic transition are studied using Monte Carlo techniques. Secondly, the effect of adding Lennard-Jones particles to an LC system modelled using the well established Gay-Berne potential is investigated. These rod-sphere mixtures are simulated using both the original set of interaction parameters and a modified version of the rod-sphere potential proposed in this work. The subject of interest is the internal structure of the binary mixture and its dependence on density, temperature, concentration and various parameters characterising the intermolecular interactions. Both...

  15. Bouncing Balls and Hot Rod Races.

    Science.gov (United States)

    Tibbs, Peggy; Sherrill, Donna

    This paper presents the Bouncing Ball Experiment which models quadratic and exponential functions, and the Hot Rod Races activity that explores velocity and acceleration. Activities include directions for the use of TI-82 and TI-83 calculators. (YDS)

  16. Dye Application, Manufacture of Dye Intermediates and Dyes

    Science.gov (United States)

    Freeman, H. S.; Mock, G. N.

    It is difficult if not impossible to determine when mankind first systematically applied color to a textile substrate. The first colored fabrics were probably nonwoven felts painted in imitation of animal skins. The first dyeings were probably actually little more than stains from the juice of berries. Ancient Greek writers described painted fabrics worn by the tribes of Asia Minor. But just where did the ancient craft have its origins? Was there one original birthplace or were there a number of simultaneous beginnings around the world?

  17. Clinical comparison between photodynamic therapy and pulsed dye laser for the treatment of port wine stains%光动力疗法与脉冲染料激光治疗鲜红斑痣的临床比较

    Institute of Scientific and Technical Information of China (English)

    吴秋菊; 周展超; 林彤; 戎惠珍; 贾高蓉

    2016-01-01

    Objective To compare the clinical efficacy and adverse effects of photodynamic therapy (PDT) versus pulsed dye laser(PDL)for the treatment of port wine stains(PWS). Methods Forty⁃five patients with PWS were enrolled in this study. The PWS lesions in each patient were randomly divided into PDT and PDL areas. Hematoporphyrin monomethyl ether of 5 mg/kg was injected intravenously into the PDT area protected from light, followed by 20⁃minute irradiation with a 532⁃nm, solid⁃state, continuous⁃wave laser(power density:80-100 mw/cm2;spot diameter: 7 cm)10 minutes later. The PDL area was treated with a single session of 595⁃nm pulsed dye laser radiation(spot diameter:7 mm;pulse width:10 ms;energy density:10-12 J/cm2). The interval between PDT and PDL treatment was no shorter than two months. Follow up visits were scheduled on day 4 and week 8 after each treatment. Adverse reactions were recorded, and photographs were taken before and 8 weeks after the treatment for evaluation of lesion regression. Results In the case of PDT area, 10 cases(22.22%)were nearly cured, 22(48.89%)achieved marked improvement, 9(20.00%)improvement, 4(8.89%)no improvement. As far as the PDL area is concerned, 6 cases(13.33%)were nearly cured, 16(35.56%)achieved marked improvement, 18(40.00%)improvement, and 5 (11.11%)no improvement. The response rate was significantly higher in the PDT area than in the PDL area(Z=2.48, P0.05). Conclusion For the treatment of PWS, both PDT and PDL are effective and safe, and single⁃session PDT appears to be superior to single⁃session PDL.%目的:探讨光动力疗法(PDT)和脉冲染料激光(PDL)治疗鲜红斑痣的疗效差异,并比较两种疗法不良反应发生情况。方法将45例鲜红斑痣患者的自身皮损随机分成PDT治疗区和PDL治疗区。PDT区治疗区在避强光条件下静脉输注5 mg/kg血卟啉注射液,10 min后开始532 nm连续波激光照射,照射20 min后结束,照射功率密度80~100 mW/cm2

  18. Double-clad nuclear fuel safety rod

    Science.gov (United States)

    McCarthy, William H.; Atcheson, Donald B.; Vaidyanathan, Swaminathan

    1984-01-01

    A device for shutting down a nuclear reactor during an undercooling or overpower event, whether or not the reactor's scram system operates properly. This is accomplished by double-clad fuel safety rods positioned at various locations throughout the reactor core, wherein melting of a secondary internal cladding of the rod allows the fuel column therein to shift from the reactor core to place the reactor in a subcritical condition.

  19. Microelectrophoresis of Silica Rods Using Confocal Microscopy.

    Science.gov (United States)

    Bakker, Henriëtte E; Besseling, Thijs H; Wijnhoven, Judith E G J; Helfferich, Peter H; van Blaaderen, Alfons; Imhof, Arnout

    2017-01-31

    The electrophoretic mobility and the zeta potential (ζ) of fluorescently labeled colloidal silica rods, with an aspect ratio of 3.8 and 6.1, were determined with microelectrophoresis measurements using confocal microscopy. In the case where the colloidal particles all move at the same speed parallel to the direction of the electric field, we record a xyz-stack over the whole depth of the capillary. This method is faster and more robust compared to taking xyt-series at different depths inside the capillary to obtain the parabolic flow profile, as was done in previous work from our group. In some cases, rodlike particles do not move all at the same speed in the electric field, but exhibit a velocity that depends on the angle between the long axis of the rod and the electric field. We measured the orientation-dependent velocity of individual silica rods during electrophoresis as a function of κa, where κ(-1) is the double layer thickness and a is the radius of the rod associated with the diameter. Thus, we determined the anisotropic electrophoretic mobility of the silica rods with different sized double layers. The size of the double layer was tuned by suspending silica rods in different solvents at different electrolyte concentrations. We compared these results with theoretical predictions. We show that even at already relatively high κa when the Smoluchowski limiting law is assumed to be valid (κa > 10), an orientation dependent velocity was measured. Furthermore, we observed that at decreasing values of κa the anisotropy in the electrophoretic mobility of the rods increases. However, in low polar solvents with κa < 1, this trend was reversed: the anisotropy in the electrophoretic mobility of the rods decreased. We argue that this decrease is due to end effects, which was already predicted theoretically. When end effects are not taken into account, this will lead to strong underestimation of the experimentally determined zeta potential.

  20. High Power Performance of Rod Fiber Amplifiers

    DEFF Research Database (Denmark)

    Johansen, Mette Marie; Michieletto, Mattia; Kristensen, Torben

    2015-01-01

    An improved version of the DMF rod fiber is tested in a high power setup delivering 360W of stable signal power. Multiple testing degrades the fiber and transverse modal instability threshold from >360W to ~290W.......An improved version of the DMF rod fiber is tested in a high power setup delivering 360W of stable signal power. Multiple testing degrades the fiber and transverse modal instability threshold from >360W to ~290W....

  1. IMPACT CONICAL ROD ON HARD LIMITER

    Directory of Open Access Journals (Sweden)

    Ulitin G.

    2014-12-01

    Full Text Available The problem is considered of longitudinal impact conical rod in article. A recommendation on the use of the approximate method of calculation is based on an analysis of the influence of design parameters on the value of the main oscillation frequency. There was obtained an equation of the displacement and stress of the rod. Engineering dependence has been proposed to determine the maximum force in the impact section.

  2. Self-diagnosing braided composite rod

    OpenAIRE

    Fangueiro, Raúl; Zdraveva, E.; Pereira, Cristiana Gonilho; Ferreira, A; Lanceros-Méndez, S.

    2010-01-01

    This paper presents the development of a braided reinforced composite rod (BCR) able to both reinforce and monitor the stress state of concrete structures. Carbon fibers have been used as sensing and reinforcing materials along with glass fiber. Various composites rods have been produced using an author patented technique based on a modified conventional braiding machine. The materials investigated were prepared with different carbon fiber content as follows: BCR2 (77% glass/23...

  3. Measurements of control rod efficiency in RBMK critical assembly upon dropping of the rods

    Energy Technology Data Exchange (ETDEWEB)

    Zhitarev, V. E., E-mail: vejitarev@nnrd.kiae.su; Kachanov, V. M.; Sergevnin, A. Yu.; Lebedev, G. V., E-mail: lgv2004@mail.ru [National Research Center Kurchatov Institute (Russian Federation)

    2014-12-15

    The efficiency of control rods in the RBMK critical assembly was measured in the case where one manual-control rod (MCR) is dropped from a steady critical state, and several other MCRs were additionally dropped after 44 s. The measured number of neutrons in the assembly during and after dropping of the rods was used to calculate the efficiency values of the rods by solution of the system of point kinetics equations. A series of methods of the initial data treatment for determination of the desired values of reactivity without the calculated corrections were used.

  4. Measurements of control rod efficiency in RBMK critical assembly upon dropping of the rods

    Science.gov (United States)

    Zhitarev, V. E.; Kachanov, V. M.; Sergevnin, A. Yu.; Lebedev, G. V.

    2014-12-01

    The efficiency of control rods in the RBMK critical assembly was measured in the case where one manual-control rod (MCR) is dropped from a steady critical state, and several other MCRs were additionally dropped after 44 s. The measured number of neutrons in the assembly during and after dropping of the rods was used to calculate the efficiency values of the rods by solution of the system of point kinetics equations. A series of methods of the initial data treatment for determination of the desired values of reactivity without the calculated corrections were used.

  5. High-throughput rod-induced electrospinning

    Science.gov (United States)

    Wu, Dezhi; Xiao, Zhiming; Teh, Kwok Siong; Han, Zhibin; Luo, Guoxi; Shi, Chuan; Sun, Daoheng; Zhao, Jinbao; Lin, Liwei

    2016-09-01

    A high throughput electrospinning process, directly from flat polymer solution surfaces induced by a moving insulating rod, has been proposed and demonstrated. Different rods made of either phenolic resin or paper with a diameter of 1-3 cm and a resistance of about 100-500 MΩ, has been successfully utilized in the process. The rod is placed approximately 10 mm above the flat polymer solution surface with a moving speed of 0.005-0.4 m s-1 this causes the solution to generate multiple liquid jets under an applied voltage of 15-60 kV for the tip-less electrospinning process. The local electric field induced by the rod can boost electrohydrodynamic instability in order to generate Taylor cones and liquid jets. Experimentally, it is found that a large rod diameter and a small solution-to-rod distance can enhance the local electrical field to reduce the magnitude of the applied voltage. In the prototype setup with poly (ethylene oxide) polymer solution, an area of 5 cm  ×  10 cm and under an applied voltage of 60 kV, the maximum throughput of nanofibers is recorded to be approximately144 g m-2 h-1.

  6. Rigid rod anchored to infinite membrane.

    Science.gov (United States)

    Guo, Kunkun; Qiu, Feng; Zhang, Hongdong; Yang, Yuliang

    2005-08-15

    We investigate the shape deformation of an infinite membrane anchored by a rigid rod. The density profile of the rod is calculated by the self-consistent-field theory and the shape of the membrane is predicted by the Helfrich membrane elasticity theory [W. Helfrich, Z. Naturforsch. 28c, 693 (1973)]. It is found that the membrane bends away from the rigid rod when the interaction between the rod and the membrane is repulsive or weakly attractive (adsorption). However, the pulled height of the membrane at first increases and then decreases with the increase of the adsorption strength. Compared to a Gaussian chain with the same length, the rigid rod covers much larger area of the membrane, whereas exerts less local entropic pressure on the membrane. An evident gap is found between the membrane and the rigid rod because the membrane's curvature has to be continuous. These behaviors are compared with that of the flexible-polymer-anchored membranes studied by previous Monte Carlo simulations and theoretical analysis. It is straightforward to extend this method to more complicated and real biological systems, such as infinite membrane/multiple chains, protein inclusion, or systems with phase separation.

  7. Long-Rod Moving-Plate Interaction

    Science.gov (United States)

    Partom, Y.

    2002-07-01

    Understanding the mechanics of interaction of a long rod projectile with a forward moving plate at an angle is essential to understanding long rod interaction with an explosive reactive armor cassette. To investigate the mechanics of such an interaction we use AUTODIN2D/EULER in plane geometry, although the problem is 3D. We assume that this is a satisfactory approximation, as we're only interested in the main features, and are not comparing fine details to experimental results. From the simulations we learn that the interaction never reaches steady state. Initially each material splits into two streams, and the interaction plane is perpendicular to the rod. But with time the interaction plane rotates slowly, until it becomes parallel to the rod, which is then able to continue moving forward without interruption. During this process interacting rod material of length DeltaL is diverted at an angle and becomes ineffective for penetrating the main target. We made many such runs to determine the dependence of DeltaL on the parameters of the problem. This dependence makes it possible to predict DeltaL for a variety of rod-plate situations.

  8. Topological optimisation of rod-stirring devices

    CERN Document Server

    Finn, Matthew D

    2011-01-01

    There are many industrial situations where rods are used to stir a fluid, or where rods repeatedly stretch a material such as bread dough or taffy. The goal in these applications is to stretch either material lines (in a fluid) or the material itself (for dough or taffy) as rapidly as possible. The growth rate of material lines is conveniently given by the topological entropy of the rod motion. We discuss the problem of optimising such rod devices from a topological viewpoint. We express rod motions in terms of generators of the braid group, and assign a cost based on the minimum number of generators needed to write the braid. We show that for one cost function -- the topological entropy per generator -- the optimal growth rate is the logarithm of the golden ratio. For a more realistic cost function,involving the topological entropy per operation where rods are allowed to move together, the optimal growth rate is the logarithm of the silver ratio, $1+\\sqrt{2}$. We show how to construct devices that realise th...

  9. International symposium on fuel rod simulators: development and application

    Energy Technology Data Exchange (ETDEWEB)

    McCulloch, R.W. (comp.)

    1981-05-01

    Separate abstracts are included for each of the papers presented concerning fuel rod simulator operation and performance; simulator design and evaluation; clad heated fuel rod simulators and fuel rod simulators for cladding investigations; fuel rod simulator components and inspection; and simulator analytical modeling. Ten papers have previously been input to the Energy Data Base.

  10. Lasing in self-assembled microcavities of CdSe/CdS core/shell colloidal quantum rods

    Science.gov (United States)

    Zavelani-Rossi, Margherita; Lupo, Maria Grazia; Krahne, Roman; Manna, Liberato; Lanzani, Guglielmo

    2010-06-01

    Colloidal semiconductor quantum rods have demonstrated many advantageous properties as light emitters such as high quantum yield, tunable emission wavelength, and polarized emission. This makes them an interesting optical gain material for laser applications. We report room-temperature gain lifetimes in core/shell CdSe/CdS quantum rods exceeding 300 ps, and show that the long gain lifetimes result from the significant reduction of Auger recombination in our quantum rods, even though the electrons are delocalized over the rod volume. We also fabricate devices by deposition of small droplets of quantum rod solution onto flat substrates. The evaporation dynamics of the droplets are governed by the coffee stain effect which leads to the formation of well defined micron-size stripes. These stripes consist of densely packed, laterally aligned quantum rods and provide optical feedback originating from the abrupt changes of refractive index at the stripe borders. We exploit the optical gain and the coffee stain mediated self-assembly and show that we can fabricate novel microlasers solely by deposition of droplets of quantum rod solutions on flat substrates.

  11. Laser therapy in plastic surgery: decolorization in port wine stains

    Science.gov (United States)

    Peszynski-Drews, Cezary; Wolf, Leszek

    1996-03-01

    For the first time laserotherapy is described as a method of port wine stain decolorization in plastic surgery. The authors present their 20-year experience in the treatment of port wine stains with the argon laser and dye laser.

  12. Local Fuel Rod Crud Prediction Tool Applications

    Energy Technology Data Exchange (ETDEWEB)

    Krammen, Michael A.; Karoutas, Zeses E.; Wang, Guoqiang; Young, Michael Y

    2009-06-15

    A code system with attendant methods has been developed for modeling local fuel rod crud. This tool is used to perform the Crud Induced Localized Corrosion (CILC) risk assessment recommended by the EPRI crud and corrosion guidelines, which were developed in response to the INPO zero fuel failures by 2010 initiatives. The methodology is in production use. This paper will describe the range of problems the methodology has already been applied to and the especial pertinence to low duty fuel applications. The methodology begins with Computational Fluid Dynamics (CFD) computations over a fuel assembly grid span. The CFD results provide detailed relative variations in local heat transfer coefficient over the grid span. These very local relative variations are used to determine very local thermal hydraulic conditions over the entire axial length of every fuel rod in a reactor core over the life of the rod in reactor. The expansion using the local relative variations is currently accomplished with the HIDUTYDRV code. The very local thermal hydraulic conditions are combined with reactor coolant crud concentrations derived from EPRI BOA analysis as input to models for predicting very local fuel rod crud deposition. The reactor coolant crud concentrations are determined over each reactor cycle by reactor system wide crud mass balance calculations. The reactor coolant crud concentrations are used to calculate local crud thickness using mass transfer models which are a function of the local thermal conditions. The advanced crud deposition models also include models for calculating local crud dryout. Local crud deposition and crud dryout are strongly dependent on very local boiling or steaming, which are predicted through the translation of the CFD results. The local crud thickness and degree of local crud dryout are key factors in determining the margin or risk for local fuel rod cladding crud induced fuel failure. The development and first application of these methods was in

  13. Regulatory perspective on incomplete control rod insertions

    Energy Technology Data Exchange (ETDEWEB)

    Chatterton, M.

    1997-01-01

    The incomplete control rod insertions experienced at South Texas Unit 1 and Wolf Creek are of safety concern to the NRC staff because they represent potential precursors to loss of shutdown margin. Even before it was determined if these events were caused by the control rods or by the fuel there was an apparent correlation of the problem with high burnup fuel. It was determined that there was also a correlation between high burnup and high drag forces as well as with rod drop time histories and lack of rod recoil. The NRC staff initial actions were aimed at getting a perspective on the magnitude of the problem as far as the number of plants and the amount of fuel that could be involved, as well as the safety significance in terms of shutdown margin. As tests have been performed and data has been analyzed the focus has shifted more toward understanding the problem and the ways to eliminate it. At this time the staff`s understanding of the phenomena is that it was a combination of factors including burnup, power history and temperature. The problem appears to be very sensitive to these factors, the interaction of which is not clearly understood. The model developed by Westinghouse provides a possible explanation but there is not sufficient data to establish confidence levels and sensitivity studies involving the key parameters have not been done. While several fixes to the problem have been discussed, no definitive fixes have been proposed. Without complete understanding of the phenomena, or fixes that clearly eliminate the problem the safety concern remains. The safety significance depends on the amount of shutdown margin lost due to incomplete insertion of the control rods. Were the control rods to stick high in the core, the reactor could not be shutdown by the control rods and other means such as emergency boration would be required.

  14. Twenty-watt average output power, picosecond thin-rod Yb:YAG regenerative chirped pulse amplifier with 200 mJ pulse energy

    OpenAIRE

    MATSUBARA, Shinichi; TANAKA, Motoharu; TAKAMA, Masaki; KAWATO, Sakae; Kobayashi, Takao

    2008-01-01

    A high-average power, laser-diode-pumped, picosecond-pulse regenerative chirpedpulse amplifier was developed by using the thin-rod Yb:YAG laser architecture. An averageoutput power of 20 W was achieved at a repetition rate of 100 kHz with an output pulse width of 2ps.

  15. Croatian Traditional Herbal Dyes For Textile Dyeing

    OpenAIRE

    Sutrlović, Ana

    2011-01-01

    Textiles, namely protein fibers, in continental part of central Europe have been traditionally dyed by natural dyes. In the process textile materials were pre or after treated by metal salts – mordants (usually: KAl(SO4)2•12H2O, SnCl2•2H2O, FeSO4•7H2O, CuSO4•5H2O). Most represented active substances in herbal extracts are flavonoid derivatives, which by complexing with metal ions constitute colored complexes. Depending on herb species and mordant applied, a wide palette of colors is available...

  16. Hair cosmetics: dyes.

    Science.gov (United States)

    Guerra-Tapia, A; Gonzalez-Guerra, E

    2014-11-01

    Hair plays a significant role in body image, and its appearance can be changed relatively easily without resort to surgical procedures. Cosmetics and techniques have therefore been used to change hair appearance since time immemorial. The cosmetics industry has developed efficient products that can be used on healthy hair or act on concomitant diseases of the hair and scalp. Dyes embellish the hair by bleaching or coloring it briefly, for temporary periods of longer duration, or permanently, depending on the composition of a dye (oxidative or nonoxidative) and its degree of penetration of the hair shaft. The dermatologist's knowledge of dyes, their use, and their possible side effects (contact eczema, cancer, increased porosity, brittleness) can extend to an understanding of cosmetic resources that also treat hair and scalp conditions. Copyright © 2013 Elsevier España, S.L.U. and AEDV. All rights reserved.

  17. Hair Dye and Hair Relaxers

    Science.gov (United States)

    ... For Consumers Consumer Information by Audience For Women Hair Dye and Hair Relaxers Share Tweet Linkedin Pin it More sharing ... products. If you have a bad reaction to hair dyes and relaxers, you should: Stop using the ...

  18. Low-threshold conical microcavity dye lasers

    DEFF Research Database (Denmark)

    Grossmann, Tobias; Schleede, Simone; Hauser, Mario

    2010-01-01

    We report on lasing in rhodamine 6G-doped, conical polymeric microcavities with high quality factors fabricated on a silicon substrate. Threshold pump energies as low as 3 nJ are achieved by free-space excitation in the quasistationary pumping regime with lasing wavelengths around 600 nm. Finite...

  19. Dyes with high affinity for polylactide

    Institute of Scientific and Technical Information of China (English)

    Liang He; Shu Fen Zhang; Bing Tao Tang; Li Li Wang; Jin Zong Yang

    2007-01-01

    Attempts were made to develop dyes with high affinity for polylactide as an alternative to the existent commercial disperse dyes.The dyes synthesized according to the affinity concept of dye to polylactide exhibited excellent dyeing properties on polylactide compared with the commercial disperse dyes.

  20. Bent Telescopic Rods in Patients With Osteogenesis Imperfecta.

    Science.gov (United States)

    Lee, R Jay; Paloski, Michael D; Sponseller, Paul D; Leet, Arabella I

    2016-09-01

    Telescopic rods require alignment of 2 rods to enable lengthening. A telescopic rod converts functionally into a solid rod if either rod bends, preventing proper engagement. Our goal was to characterize implant bending as a mode of failure of telescopic rods used in the treatment of osteogenesis imperfecta in children. We conducted a retrospective review of our osteogenesis imperfecta database for patients treated with intramedullary telescopic rods at our institution from 1992 through 2010 and identified 12 patients with bent rods. The 6 boys and 6 girls had an average age at the time of initial surgery of 3.1 years (range, 1.8 to 8.3 y) and a total of 51 telescoping rods. Clinic notes, operative reports, and radiographs were reviewed. The rods were analyzed for amount of lengthening, characteristics of bending, presence of cut out, or disengagement from an anchor point. Bends in the rods were characterized by their location on the implant component. The bent and straight rods were compared. Data were analyzed with the Mann-Whitney test (statistical significance set at P≤0.05). Of the 51 telescoping rods, 17 constructs (33%) bent. The average interval between surgery and rod bending was 4.0 years (range, 0.9 to 8.2 y). Before bending, 11 of 17 telescoping rods had routine follow-up radiographs for review. In 10 of the rods, bending was present when early signs of rod failure were first detected. Rod bending did not seem to be related to rod size. There was no area on the rod itself that seemed more susceptible to bending. Rod bending can be an early sign of impending rod failure. When rod bending is first noted, it may predispose the rod to other subsequent failures such as loss of proximal and distal fixation and cut out. Rod bending should be viewed as an indicator for closer monitoring of the patient and discussions regarding future need for rod exchange. Level III-retrospective review.

  1. Hair care and dyeing.

    Science.gov (United States)

    Draelos, Zoe Diana

    2015-01-01

    Alopecia can be effectively camouflaged or worsened through the use of hair care techniques and dyeing. Proper hair care, involving hair styling and the use of mild shampoos and body-building conditioners, can amplify thinning scalp hair; however, chemical processing, including hair dyeing, permanent waving, and hair straightening, can encourage further hair loss through breakage. Many patients suffering from alopecia attempt to improve their hair through extensive manipulation, which only increases problems. Frequent haircuts to minimize split ends, accompanied by gentle handling of the fragile fibers, is best. This chapter offers the dermatologist insight into hair care recommendations for the alopecia patient.

  2. Dye solar cell research

    CSIR Research Space (South Africa)

    Cummings, F

    2009-11-01

    Full Text Available stream_source_info Cummings_2009.pdf.txt stream_content_type text/plain stream_size 3362 Content-Encoding UTF-8 stream_name Cummings_2009.pdf.txt Content-Type text/plain; charset=UTF-8 DYE SOLAR CELL RESEARCH Franscious... Cummings Energy and Processes Materials Science and Manufacturing Council for Scientific and Industrial Research P.O. Box 395 Pretoria 0001, South Africa 27 November 2009 CONTENT head2rightBackground head2rightCSIR Dye Solar Cell Research head2...

  3. Axial Vibration Confinement in Nonhomogenous Rods

    Directory of Open Access Journals (Sweden)

    S. Choura

    2005-01-01

    Full Text Available A design methodology for the vibration confinement of axial vibrations in nonhomogenous rods is proposed. This is achieved by a proper selection of a set of spatially dependent functions characterizing the rod material and geometric properties. Conditions for selecting such properties are established by constructing positive Lyapunov functions whose derivative with respect to the space variable is negative. It is shown that varying the shape of the rod alone is sufficient to confine the vibratory motion. In such a case, the vibration confinement requires that the eigenfunctions be exponentially decaying functions of space, where the notion of spatial domain stability is introduced as a concept dual to that of the time domain stability. It is also shown that vibration confinement can be produced if the rod density and/or stiffness are varied with respect to the space variable while the cross-section area is kept constant. Several case studies, supporting the developed conditions imposed on the spatially dependent functions for vibration confinement in vibrating rods, are discussed. Because variation in the geometric and material properties might decrease the critical buckling loads, we also discuss the buckling problem.

  4. Wetting of a partially immersed compliant rod

    Science.gov (United States)

    Hui, Chung-Yuen; Jagota, Anand

    2016-11-01

    The force on a solid rod partially immersed in a liquid is commonly used to determine the liquid-vapor surface tension by equating the measured force required to remove the rod from the liquid to the vertical component of the liquid-vapor surface tension. Here, we study how this process is affected when the rod is compliant. For equilibrium, we enforce force and configurational energy balance, including contributions from elastic energy. We show that, in general, the contact angle does not equal that given by Young's equation. If surface stresses are tensile, the strain in the immersed part of the rod is found to be compressive and to depend only on the solid-liquid surface stress. The strain in the dry part of the rod can be either tensile or compressive, depending on a combination of parameters that we identify. We also provide results for compliant plates partially immersed in a liquid under plane strain and plane stress. Our results can be used to extract solid surface stresses from such experiments.

  5. Dielectric rod feed for compact range reflector

    CERN Document Server

    Balabukha, Nikolay P; Shapkina, Natalia E

    2014-01-01

    A dielectric rod feed with a special radiation pattern of a tabletop form used for the compact range reflector is developed and analyzed. Application of this feed increases the size of the compact range quiet zone generated by the reflector. The feed consists of the dielectric rod made of polystyren, the rod is inserted into the circular waveguide with a corrugated flange. The waveguide is excited by the H11-mode. The rod is covered by the textolite biconical bushing and has a fluoroplastic insert in the vicinity of the bushing. Mathematical modeling was used to obtain the parameters of the feed for the optimal tabletop form of the radiation pattern. The problem of the electromagnetic radiation was solved for metal-dielectric bodies of rotation by method of integral equations with further solving of the problem of the synthesis for feed parameters. The dielectric rod feed was fabricated for the X-frequency range. Feed amplitude and phase patterns were measured in the frequency range 8.2-12.5 GHz. Presented re...

  6. Textile dye decolorization using cyanobacteria.

    Science.gov (United States)

    Parikh, Amit; Madamwar, Datta

    2005-03-01

    Cyanobacterial cultures isolated from sites polluted by industrial textile effluents were screened for their ability to decolorize cyclic azo dyes. Gloeocapsa pleurocapsoides and Phormidium ceylanicum decolorized Acid Red 97 and FF Sky Blue dyes by more than 80% after 26 days. Chroococcus minutus was the only culture which decolorized Amido Black 10B (55%). Chlorophyll a synthesis in all cultures was strongly inhibited by the dyes. Visible spectroscopy and TLC confirmed that color removal was due to degradation of the dyes.

  7. Compact and highly efficient laser pump cavity

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Jim J. (Dublin, CA); Bass, Isaac L. (Castro Valley, CA); Zapata, Luis E. (Livermore, CA)

    1999-01-01

    A new, compact, side-pumped laser pump cavity design which uses non-conventional optics for injection of laser-diode light into a laser pump chamber includes a plurality of elongated light concentration channels. In one embodiment, the light concentration channels are compound parabolic concentrators (CPC) which have very small exit apertures so that light will not escape from the pumping chamber and will be multiply reflected through the laser rod. This new design effectively traps the pump radiation inside the pump chamber that encloses the laser rod. It enables more uniform laser pumping and highly effective recycle of pump radiation, leading to significantly improved laser performance. This new design also effectively widens the acceptable radiation wavelength of the diodes, resulting in a more reliable laser performance with lower cost.

  8. Luminescent molecular rods - transition-metal alkynyl complexes.

    Science.gov (United States)

    Yam, Vivian Wing-Wah; Wong, Keith Man-Chung

    2005-01-01

    A number of transition-metal complexes have been reported to exhibit rich luminescence, usually originating from phosphorescence. Such luminescence properties of the triplet excited state with a large Stoke's shift, long lifetime, high luminescence quantum yield as well as lower excitation energy, are envisaged to serve as an ideal candidate in the area of potential applications for chemosensors, dye-sensitized solar cells, flat panel displays, optics, new materials and biological sciences. Organic alkynes (poly-ynes), with extended or conjugatedπ-systems and rigid structure with linear geometry, have become a significant research area due to their novel electronic and physical properties and their potential applications in nanotechnology. Owing to the presence of unsaturated sp-hybridized carbon atoms, the alkynyl unit can serve as a versatile building block in the construction of alkynyl transition-metal complexes, not only throughσ-bonding but also viaπ-bonding interactions. By incorporation of linear alkynyl groups into luminescent transition-metal complexes, the alkynyl moiety with goodσ-donor,π-donor andπ-acceptor abilities is envisaged to tune or perturb the emission behaviors, including emission energy (color), intensity and lifetime by its role as an auxiliary ligand as well as to govern the emission origin from its direct involvement. This review summarizes recent efforts on the synthesis of luminescent rod-like alkynyl complexes with different classes of transition metals and details the effects of the introduction of alkynyl groups on the luminescence properties of the complexes.

  9. Rod consolidation at the West Valley Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, W.J.

    1986-12-01

    A rod consolidation demonstration with irradiated pressurized water reactor fuel was recently conducted by personnel from Nuclear Assurance Corporation and West Valley Nuclear Services Company at the West Valley Demonstration Project in West Valley, New York. The rod consolidation demonstration involved pulling all of the fuel rods from six fuel Assemblies. In general, the rod pulling proceeded smoothly. The highest compaction ratio attained was 1:8:1. Among the total of 1074 fuel rods were some known degraded rods (they had collapsed cladding, a result of in-reactor fuel densification), but no rods were broken or dropped during the demonstration. One aim was to gather information on the effect of rod consolidation operations on the integrity of the fuel rods during subsequent handling and storage. Another goal was to collect information on the condition and handling of intact, damaged, and failed fuel that has been in storage for an extended period. 9 refs., 8 figs., 1 tab.

  10. Magnetic switch for reactor control rod. [LMFBR

    Science.gov (United States)

    Germer, J.H.

    1982-09-30

    A magnetic reed switch assembly is described for activating an electromagnetic grapple utilized to hold a control rod in position above a reactor core. In normal operation the magnetic field of a permanent magnet is short-circuited by a magnetic shunt, diverting the magnetic field away from the reed switch. The magnetic shunt is made of a material having a Curie-point at the desired release temperature. Above that temperature the material loses its ferromagnetic properties, and the magnetic path is diverted to the reed switch which closes and short-circuits the control circuit for the control rod electro-magnetic grapple which allows the control rod to drop into the reactor core for controlling the reactivity of the core.

  11. REUSE OF DECOLORIZED DYEING EFFLUENTS IN REPEATED DYEINGS

    Directory of Open Access Journals (Sweden)

    ÖNER Erhan

    2016-05-01

    Full Text Available In this experimental work, the effluents of the reactive and disperse dyeings were reused in the next dyeing after the decolourization by ozone gas. Accordingly, the polyester woven samples were dyed with C.I. Disperse Yellow 160, C.I. Disperse Red 77 and C.I. Disperse Blue 79:1, and the cotton woven samples were dyed with C.I. Reactive Yellow 176, C.I. Reactive Red 239 and C.I. Reactive Blue 221. The effluents of the dyeings with these dyes and also with their mixtures were decolorized by ozone gas. The colours of the samples dyed with the decolorized effluents were compared with the original dyeings (standards and the colour differences were calculated. Under the experimental conditions of this investigation, the many of the dyeing effluents were decolorized successfully, except the effluent of C.I. Disperse Red 77. In the case that this red disperse dye present in the dyebath, the decolorized effluent had a slight reddish colour. The colour differences between the original dyeing (standard and the samples dyed with the decolorized effluent are mostly below the tolerance (DE<1 or slightly above the tolerance. The solid colours and uniform dyeings were achieved in the dyeings. The method seems promising in decreasing the amount of water used in textile dyeings.

  12. OPTIMIZATION OF DYEING PARAMETERS TO DYE COTTON WITH CARROT EXTRACTION

    Directory of Open Access Journals (Sweden)

    MIRALLES Verónica

    2017-05-01

    Full Text Available Natural dyes derived from flora and fauna are believed to be safe because of non-toxic, non-carcinogenic and biodegradable nature. Furthermore, natural dyes do not cause pollution and waste water problems. Natural dyes as well as synthetic dyes need the optimum parameters to get a good dyeing. On some occasions, It is necessary the use of mordants to increase the affinity between cellulose fiber and natural dye, but there are other conditions to optimize in the dyeing process, like time, temperature, auxiliary porducts, etc. In addition, the optimum conditions are different depends on the type of dye and the fiber nature. The aim of this work is the use of carrot extract to dye cotton fabric by exhaustion at diverse dyeing conditions. Diffferent dyeing processes were carried out to study the effect of pH condition and the temperature, using 7, 6 and 4 pH values and 95 ºC and 130ºC for an hour. As a result some images of dyed samples are shown. Moreover, to evaluate the colour of each sample CIELAB parameters are analysed obtained by reflexion spectrophotometre. The results showed that the temperature used has an important influence on the colour of the dyed sample.

  13. Third-order nonlinear optical properties of organic azo dyes by using strength of nonlinearity parameter and Z-scan technique

    Science.gov (United States)

    Motiei, H.; Jafari, A.; Naderali, R.

    2017-02-01

    In this paper, two chemically synthesized organic azo dyes, 2-(2,5-Dichloro-phenyazo)-5,5-dimethyl-cyclohexane-1,3-dione (azo dye (i)) and 5,5-Dimethyl-2-tolylazo-cyclohexane-1,3-dione (azo dye (ii)), have been studied from optical Kerr nonlinearity point of view. These materials were characterized by Ultraviolet-visible spectroscopy. Experiments were performed using a continous wave diode-pumped laser at 532 nm wavelength in three intensities of the laser beam. Nonlinear absorption (β), refractive index (n2) and third-order susceptibility (χ (3)) of dyes, were calculated. Nonlinear absorption coefficient of dyes have been calculated from two methods; 1) using theoretical fits and experimental data in the Z-scan technique, 2) using the strength of nonlinearity curves. The values of β obtained from both of the methods were approximately the same. The results demonstrated that azo dye (ii) displays better nonlinearity and has a lower two-photon absorption threshold than azo dye (i). Calculated parameter related to strength of nonlinearity for azo dye (ii) was higher than azo dye (i), It may be due to presence of methyl in azo dye (ii) instead of chlorine in azo dye (i). Furthermore, The measured values of third order susceptibility of azo dyes were from the order of 10-9 esu . These azo dyes can be suitable candidate for optical switching devices.

  14. Alzheimer's Dye Test?

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    Massachusetts Institute of Technology (MIT) scientists have developed a new dye that could offer noninvasive early diagnosis of Alzheimer's disease, a discovery that could aid in monitoring the progression of the disease and in studying the efficacy of new treatments to stop it. The work is published in Angewandte Chemie. Today, doctors can only…

  15. Alzheimer's Dye Test?

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    Massachusetts Institute of Technology (MIT) scientists have developed a new dye that could offer noninvasive early diagnosis of Alzheimer's disease, a discovery that could aid in monitoring the progression of the disease and in studying the efficacy of new treatments to stop it. The work is published in Angewandte Chemie. Today, doctors can only…

  16. Microwave-Assisted Synthesis of Titania Nanocubes, Nanospheres and Nanorods for Photocatalytic Dye Degradation

    Directory of Open Access Journals (Sweden)

    Suprabha T

    2008-01-01

    Full Text Available Abstract TiO2nanostructures with fascinating morphologies like cubes, spheres, and rods were synthesized by a simple microwave irradiation technique. Tuning of different morphologies was achieved by changing the pH and the nature of the medium or the precipitating agent. As-synthesized titania nanostructures were characterized by X-ray diffraction (XRD, UV–visible spectroscopy, infrared spectroscopy (IR, BET surface area, photoluminescence (PL, scanning electron microscopy (SEM and transmission electron microscopy (TEM, and atomic force microscopy (AFM techniques. Photocatalytic dye degradation studies were conducted using methylene blue under ultraviolet light irradiation. Dye degradation ability for nanocubes was found to be superior to the spheres and the rods and can be attributed to the observed high surface area of nanocubes. As-synthesized titania nanostructures have shown higher photocatalytic activity than the commercial photocatalyst Degussa P25 TiO2.

  17. HIGH STRENGTH CONTROL RODS FOR NEUTRONIC REACTORS

    Science.gov (United States)

    Lustman, B.; Losco, E.F.; Cohen, I.

    1961-07-11

    Nuclear reactor control rods comprised of highly compressed and sintered finely divided metal alloy panticles and fine metal oxide panticles substantially uniformly distributed theretbrough are described. The metal alloy consists essentially of silver, indium, cadmium, tin, and aluminum, the amount of each being present in centain percentages by weight. The oxide particles are metal oxides of the metal alloy composition, the amount of oxygen being present in certain percentages by weight and all the oxygen present being substantially in the form of metal oxide. This control rod is characterized by its high strength and resistance to creep at elevated temperatures.

  18. Sensitivity study of control rod depletion coefficients

    OpenAIRE

    Blomberg, Joel

    2015-01-01

    This report investigates the sensitivity of the control rod depletion coefficients, Sg, to different input parameters and how this affects the accumulated 10B depletion, β. Currently the coefficients are generated with PHOENIX4, but the geometries can be more accurately simulated in McScram. McScram is used to calculate Control Rod Worth, which in turn is used to calculate Nuclear End Of Life, and Sg cannot be generated in the current version of McScram. Therefore, it is also analyzed whether...

  19. Synthesis of azo pyridone dyes

    OpenAIRE

    Mijin Dušan Ž.; Ušćumlić Gordana S.; Valentić Nataša V.; Marinković Aleksandar D.

    2011-01-01

    Over 50% of all colorants which are used nowdays are azo dyes and pigments, and among them arylazo pyridone dyes (and pigments) have became of interest in last several decades due to the high molar extinction coefficient, and the medium to high light and wet fastness properties. They find application generally as disperse dyes. The importance of disperse dyes increased in the 1970s and 1980s due to the use of polyester and nylon as the main synthetic fibers. Also, disperse dyes were use...

  20. TEXTILE DYEING AND FINISHING JOURNAL

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Abstract: Optim is dyed with Lanasol CE series dyes by micro-suspension technology, and the dyeing result is compared with that by traditional process. The optimal micro-suspension dyeing process is determined as follows: formic acid 1.5% (owl), micro-suspension promoter WR1.0% (owf), micro-suspension promoter TS 0.5 % (owl), dyestuff 5% (owf). The results show that micro-suspension dyeing increases the dye uptake percentage and colour fixation rate significantly; improves the handle and bulkiness without damaging the colour fastness of the dyed fabric.