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  • 1
    Electronic Resource
    Electronic Resource
    Investigation of Defects in the Edge Region of Multicrystalline Solar Silicon Ingots (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 108-109 (Dec. 2005), p. 531-538 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: The structural and electrical properties of as grown multicrystalline (mc) solar silicon have been characterized with special emphasis on the ingot's edge regions. For this purpose a vertical cross section of an mc-Si Bridgman ingot was investigated by Fourier transform infrared spectroscopy (FTIR), laser scattering tomography (LST), lateral photovoltage scanning (LPS), infrared microscopy and microwave detected photoconductivity decay (&PCD). Images of the distribution of dislocations, grain boundaries, precipitates, impurities (O, N, C) and the minority charge carrier lifetime were obtained, partly differentiating the defects by their electrical activity. In particular the LPS method displays dopant striations indicating the shape of the phase boundary. Deviations of the phase boundary from a slightly convex shape in the middle of the ingot to a concave one in the vicinity of the side walls could be observed. The existence of an horizontal temperature gradient deduced from this shape is the reason for convection in the melt. The influence on the concentration profiles of interstitial oxygen and the correlation with the minority charge carrier lifetime are discussed
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/22/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.108-109.531.pdf
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  • 2
    Electronic Resource
    Electronic Resource
    Determination of the density of IRMPD-generated radicals by transmission and lif measurements
    Amsterdam : Elsevier
    Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy Section 46 (1990), S. 475-477 
    Details
    ISSN: 0584-8539
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0584-8539(90)80155-R
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  • 3
    Electronic Resource
    Electronic Resource
    Infrared laser-induced post-pulse dissociation of CF2HCl and CF2Cl2 under high pressure and fluence conditions (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 105 (1996), S. 9478-9485 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The unimolecular decomposition of the halogenated methanes CF2HCl (one main channel) and CF2Cl2 (two main channels) in the focused beam of a pulsed CO2 laser under high pressure and fluence conditions (p=100 Pa–2 kPa; Φ=5–200 J/cm2) was studied by a special laser-induced fluorescence (LIF) technique, permitting spatially resolved fragment concentration measurements in the focal region. Considerable amounts of CF2 product were formed after the end of the laser pulse. In the one-channel-dissociation case of CF2HCl LIF measurements of the CF2 yield distribution Y(z,r) can be related to the spatial distribution of the average absorbed energy in the parent molecules. Only part of the absorbed energy is consumed by multiphoton dissociation, while most reactant molecules remain highly vibrationally excited in the focus volume far into the double cone. Using the long-lived CF2 also as a probe for measuring the rotational, translational, and vibrational temperatures, the redistribution of the internal energy in the molecules and fragments involved is monitored. The post-pulse production of CF2 is shown to be caused by the energy pooling v–v transfer mechanism, while contributions of pyrolytic and gas dynamic processes are of little importance. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.472781
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  • 4
    Electronic Resource
    Electronic Resource
    Selective Estrogen Receptor Modulators: Tissue Actions and Potential for CNS Protection (2002)
    Oxford, UK : Blackwell Publishing Ltd
    CNS drug reviews 8 (2002), S. 0 
    Details
    ISSN: 1527-3458
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Significant physiologic changes occur during menopause. Evidence exists to suggest that estrogen may be neuroprotective under specific conditions. However, there are limitations in the neuroprotection afforded by standard hormone therapy. Accordingly, alternative agents with selected estrogenic effects may hold even greater promise rather than conventional hormone replacement therapy for the prevention and treatment of CNS injury. Recently, a variety of selective estrogen receptor modulators (SERMs) have been developed to retain the favorable and minimize the adverse side effects of estrogens. This review focuses on the CNS and known neuroprotective effects of two specific SERMs, raloxifene and arzoxifene. Recent studies hint that raloxifene and arzoxifene are neuroprotective and may preserve some elements of cognitive function. However, the mechanism of action is not well described and it is unclear if the beneficial effects of SERMs rely on activation of estrogen receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1527-3458.2002.tb00230.x
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  • 5
    Electronic Resource
    Electronic Resource
    LIF probing with high spatial resolution in the process zone of a photolysis laser (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 129-134 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A laser-induced fluorescence (LIF) method for spatially resolved fragment detection and characterization in the radiation field of a photolysis laser is described. Measurements of the radiation field of a focused beam showed up highly inhomogeneous irradiation conditions, resulting in a strong local dependence of the laser-induced processes. The spatial resolution of the method is based on stepping-motor-controlled motion of the focusing lens of the photolysis laser versus the probe laser focused to a diameter (1/e2) of 58 μm. This diameter corresponds to the spatial inhomogeneities of the quantities studied in this article. However, the monitored volume (5.3×10−6 cm3) also represents a compromise between acceptable S/N ratio and spectral resolution. The advantages and limits of this spatially resolved fluorescence (SRF) technique are discussed. Owing to its simplicity it can be readily implemented in existing laser photolysis equipment with conventional LIF detection. This method is currently being applied to the study of IR laser chemical reactions. A few examples illustrate the range of applicability of the method by providing information on the fluence dependence of product formation, on mass transport kinetics of molecular species in the context of heterogeneous laser processing, and on the internal energy distribution of the dissociation products. They show the much higher information content of SRF measurements as compared with conventional LIF measurements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1144784
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  • 6
    Electronic Resource
    Electronic Resource
    Laser-induced fluorescence spectroscopy of SiF produced by IR multiple-photon dissociation of SiF"4
    Amsterdam : Elsevier
    Journal of Molecular Structure 218 (1990), S. 225-230 
    Details
    ISSN: 0022-2860
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0022-2860(90)80271-K
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of Nitrogen Doping on the Formation of Planar Defects in 4H-SiC (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 483-485 (May 2005), p. 39-42 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Planar defects have been found in nitrogen doped 2" 4H-SiC crystals grown on off-axis seeds. The doping level was 1×1019cm-3, which is below the critical one for the thermally activated cubic stacking fault formation in the 4H matrix. Planar defects in the doped region are nucleated on the whole seed surface outside the growth facet. They are coexisting 15R and 6H lamellas of unitcell height as revealed by means of luminescence and high resolution transmission electron microscopy. These inclusions are preferably formed at the rim of the growth facet, where polytype change occurs after switching off the nitrogen flow during growth
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/10/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.483-485.39.pdf
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  • 8
    Electronic Resource
    Electronic Resource
    Transportvorgänge und Oberflächenreaktionen bei der Verbrennung graphitischen Kohlenstoffs (1956)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 28 (1956), S. 181-189 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Rohre aus spektralreinem graphitischen Kohlenstoff wurden mit Luft und N2/O2-Gemischen anderer Zusammensetzung laminar durchströmt und die Abbrandgeschwindigkeit als Funktion von Gasdruck, Temperatur und Strömungsgeschwindigkeit gemessen. Dabei wurde festgestellt  -  wie bereits früher vermutet  - , daß die für den Umsatz maßgebenden Gesetzmäßigkeiten mit steigender Temperatur zweimal wechseln. In jedem der drei Temperaturbereiche bestimmt ein jeweils anderer Teilvorgang die gesamte Umsatzgeschwindigkeit. Bei relativ niedrigen Temperaturen (500-600° C), bei denen die gesamte innere Oberfläche des porösen Festkörpers durch die Umsetzung ausgenutzt wird, ist dies die heterogene chemische Reaktion. Mit steigender Temperatur (um 750° C) wird dieses Gebiet abgelöst durch den Bereich vorherrschender Porendiffusion. Hier zieht sich die an der Reaktion teilnehmende Zone des inneren Porengefüges immer mehr zur äußeren Oberfläche hin zurück, und die Temperaturabhängigkeit der Umsatzgeschwindigkeit entspricht nur noch dem halben Wert der Aktivierungsenergie der chemischen Reaktion. Bei hohen Temperaturen (oberhalb 1200° C) schließlich gewinnt die Diffusion durch die an der äußeren Feststoffoberfläche anliegende hydrodynamische Gasgrenzschicht entscheidenden Einfluß auf den Umsatz, der dann praktisch unabhängig von der Temperatur wird.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330280309
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  • 9
    Electronic Resource
    Electronic Resource
    Zur Kinetik der Methylchlorid-Bildung, aus Methanol und Chlorwasserstoff an Aluminiumoxid (1970)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 42 (1970), S. 1215-1219 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Die Kinetik der Umsetzung von Chlorwasserstoff mit Methanol in der Gasphase an Aluminiumoxid als Katalysator sowie die Katalysator-Alterung wurden untersucht, um Unterlagen zur Bemessung von Reaktoren zu gewinnen. Die Reaktion ist von 1. Ordnung in bezug auf Chlorwasserstoff und nahezu unabhängig vom Methanol-Partialdruck. Die differentielle Reaktionskonstante ist der spez. Oberfläche des Katalysators proportional, unabhängig von dessen Kristallmodifikation, wobei sich eine Reaktionshemmung durch Porendiffusion bemerkbar macht, die nach der Theorie von Thiele erfaßt wird. Die Katalysator-Alterung ist im wesentlichen auf Kohlenstoff-Abscheidung zurückzuführen, die Restaktivität nimmt exponentiell mit der Zeit ab.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330421908
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