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  • 1
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    German Medical Science GMS Publishing House; Düsseldorf
    In:  83. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie; 20120516-20120520; Mainz; DOC12hnod034 /20120404/
    Publication Date: 2012-04-05
    Keywords: ddc: 610
    Language: German
    Type: conferenceObject
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  • 2
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary Several sensitive detection techniques, such as excitation spectroscopy or resonant two-photon ionization spectroscopy are applied to laser spectroscopy with sub-Doppler resolution in collimated molecular beams. Due to internal cooling during the adiabatic expansion in supersonic beams rotational temperatures below 10 K can be reached which results in a drastic simplification of otherwise complex molecular spectra. Different schemes of optical-optical double resonance spectroscopy with two cw or pulsed narrow band lasers are discussed which allow the unambiguous assignment of perturbed molecular spectra. The techniques are illustrated by their application to NO2, SO2, Cs2 and to the study of Rydberg states of Li2.
    Notes: Zusammenfassung Empfindliche Nachweismethoden der Laserspektroskopie, wie z. B. die Anregungsspektroskopie oder die resonante Zweiphotonen-Ionisation werden angewandt auf die Doppler-freie Untersuchung kleiner Moleküle, wie NO2 und SO2 in kollimierten Überschallstrahlen. Durch die drastische Abkühlung bei der adiabatischen Expansion können Rotationstemperaturen unter 10 K erreicht werden, was die Liniendichte in den Spektren stark reduziert und damit die Analyse der Spektren wesentlich vereinfacht. Verschiedene Techniken der optischen-optischen Doppelresonanz-Spektroskopie mit zwei kontinuierlichen oder gepulsten Lasern werden illustriert am Beispiel der Untersuchung von Rydberg-Zuständen von Li2 und des langreichweitigen Potentials von Cs2. Der Vorteil dieser Techniken für die Analyse komplexer Molekülspektren wird diskutiert.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1435-604X
    Keywords: Keywords: Laser-induced ignition of endotracheal tubes; Laser safety; Laser surgery; Upper aerodigestive tract; Vaporisation cooling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract. Laser-induced ignition of endotracheal tubes is a serious problem in CO2 laser surgery of the upper aerodigestive tract. A new tube built of composite materials with a foam at its surface is protected by vaporisation of water from the wet foam. This tube and a flexible metallic tube of stainless steel were tested experimentally against the radiation of various lasers such as CO2, holmium/YAG, Nd/YAG, Nd/YAG frequency doubled in KD*P, argon and excimer. At laser power densities of 103 W/cm2, the shaft of the metallic tube was damaged within seconds whereas the compound tube was stable for more than 2 min; the damage threshold of the new tube was found to be at 3.2×106 W/cm2. While the compound tube was found to be sufficiently laser resistant, the metallic tube was found to exhibit functional damage, in particular the PVC inflation conduits inside of the tube were destroyed.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1435-604X
    Keywords: Keywords: Anisotropic heat conduction; Laser induced heating of endotracheal tubes; Laser safety; Laser surgery; Vaporisation cooling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract. An infrared camera was used to measure the temperature rise which takes place in endotracheal tubes exposed to a 20 W CO2 laser beam. It was seen that a metallic tube was heated up within 1 s to temperatures of 200–300°C which was very destructive to the PVC conduits inside the tube. A compound tube, on the other hand, reached temperatures of only 60°C at its inner surface after an exposure of 20 s. The experimental results can be explained by a physical model which uses the heat conduction and the heat capacities of both tubes. Whereas heat conduction in the metal tube is isotropic, heat conduction in the compound tube is anisotropic with a high conductivity along the outer surface and a low conductivity to the inside. This anisotropy and the cooling mechanism in the compound tube due to vaporising water are the reason for the high laser resistance of the tube.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1434-6079
    Keywords: 33.80 ; 35.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Photofragment spectroscopy of N 2 + has been studied in the wavelength range 343–404 nm using an excimer-pumped dye laser with a spectral resolution of 0.2 cm−1. The observed bands are assigned to transitions from thev″=23−26 levels of theX 2Σ g + state to highlying rovibrational levels (v′≈46–48) of theB 2Σ u + state, forming quasibound (predissociating) states above the dissociation limit N+(3 P)+N(4 S 0). Measurement of the photofragment kinetic energies allows to establish an absolute energy scale for the transitions with respect to the dissociation limit. Molecular constants for the lower and upper states of the observed transitions are determined. The measurements allow the first direct determination of the N 2 + dissociation energyD 0 0 (N 2 + ). Some high-resolution (0.04 cm−1) measurements show the fine-structure splitting and lifetime broadening of the excitation lines.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1434-6079
    Keywords: 33.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The direct photodissociation process SO++hv→S++O has been studied using the technique of ion photofragment spectroscopy. The kinetic energy distribution of the S+ photofragments has been measured for selected wavelengths in the range λ=308–514.5 nm. Transitions from the metastablea 4∏ state to the dissociative 14∑+ state as well as from theX 2∏ ground state to a higher-lying2∏ state have been observed. From the vibrationally resolved kinetic energy spectra, the potential curve of the repulsive 14∑+ state has been determined for the range of internuclear distancesR=3.0–4.5a 0. In addition, the analysis gives the vibrational population of the SO+ (a 4∏) ions after dissociative electron-impact ionization of SO2 in the low-pressure monoplasmatron ion source.
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  • 7
    ISSN: 1434-6079
    Keywords: 33.80.Gj
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The accuracy for the direct measurement of the dissociation energy of the N 2 + B2Σ u +-state was significantly improved by using frequency doubled laser light, which enables the authors to excite from lowerv″-levels and additionally to calibrate the fundamental laser wavelength with an iodine cell. The obtained value is:D 8(N 2 + )=70248±6 cm−1.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1434-6079
    Keywords: 33.20 ; 35.20 ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Rotationally cold Na3-molecules are formed during the adiabatic expansion of an argon beam, seeded with 5% sodium vapor. With a single mode tunable dyelaser crossing the molecular beam perpendicularly within the ion source of a mass spectrometer the Na3-molecules are excited into levels of the2 A 2-state which are then ionized by acw argon-laser. Rotational lines of the electronic2 A 2 ←X 2 B 2 transition and their hyperfine structure could be resolved using an OODR-technique. A preliminary analysis of the measured spectra is discussed and a comparison of the experimental results with ab initio calculations is presented.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Chemical Physics Letters 114 (1985), S. 125-132 
    ISSN: 0009-2614
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Chemical Physics Letters 166 (1990), S. 551-559 
    ISSN: 0009-2614
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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