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  • 1
    Electronic Resource
    Electronic Resource
    Particle concentration measurements by phase-doppler anemometry in complex dispersed two-phase flows (1995)
    Springer
    Experiments in fluids 18 (1995), S. 187-198 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Particle concentration or mass flux measurements by phase-Doppler anemometry are based on counting the number of particles crossing the probe volume. In complex particulate flows this requires the knowledge of the particle size-dependent cross-section of the measurement volume perpendicular to the instantaneous particle velocity for each sample. A new method is presented which allows to estimate the instantaneous particle velocity using a one-component PDA-system with the aid of the integral value under the envelope of the Doppler signal. The envelope is reliably determined by a recently developed analogue burst detection electronic circuit using narrow band-pass filters and a synchro detector. The particle size-dependent measurement volume is obtained by the mean log-arithmic amplitude method introduced by Qiu and Sommerfeld (1992). The special signal processing requirements for realizing this method were implemented in a novel signal processor which additionally involves a burst detection based on an online estimation of the signal-to-noise ratio (SNR) and hence the data aquisition is only triggered for signals above a pre-set SNR level. The estimation of the signal frequency and phase is based on the calculation of the cross-spectral density using a hardware FFT (Fast Fourier Transform) chip. In order to demonstrate the accuracy of the novel method for particle concentration and mass flux determination, measurements were performed in a liquid spray and a particle laden swirling flow. Especially in the swirling flow, the particles exhibit random trajectories through the measurement volume and the powerfulness of the present method is demonstrated especially for this complex flow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230264
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  • 2
    Electronic Resource
    Electronic Resource
    Optimal Generation of Cutter Path in the Form of Polar Coordinate for NC Machining of Noncircular Contours (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 339 (May 2007), p. 59-65 
    Details
    ISSN: 1013-9826
    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: This paper proposes an optimal interpolation approach to generate cutter paths in theform of polar coordinate for machining noncircular contours. The cutter path obtained with theapproach consists of a series of Archimedes’ spiral segments and the number of segments is thefewest under the condition that the interpolation error completely satisfies the specified limit value.It can be also evidenced that the profile error of the machined contour due to the cutter path isperfectly controlled within the specified interpolation accuracy limit. The result of applying theapproach to the contour machining of a disc cam sufficiently illustrates the effectiveness of theproposed approach
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/53/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.339.59.pdf
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  • 3
    Electronic Resource
    Electronic Resource
    The fluid theory of steady-state magnetically confined electron clouds sustained by ionization and emission (1992)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 14 (1992), S. 369-378 
    Details
    ISSN: 0392-6737
    Keywords: Nonneutral plasmas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The fluid theory is applied to study the axisymmetrical steady-state magnetically confined electron clouds sustained by ionization or emission. These electron clouds can be obtained by means of low-pressure Penning discharge, thermoelectronic emission, ion beam ionization, etc. In the electron clouds the property of motion of electrons can be described by the fluid equations: the continuity equation, the momentum equation, the energy equation, the heat transfer equation and the electrostatic field equation. These equations are used to discuss the equilibrium between supplement and escape of electrons in the clouds and the distributions of the physical quantities of some long electron clouds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02456772
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  • 4
    Electronic Resource
    Electronic Resource
    A New Extracorporeal Perfusion System: Prolongation of Liver Organ Vitality beyond 24 Hours (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 723 (1994), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1994.tb36786.x
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  • 5
    Electronic Resource
    Electronic Resource
    Theory of homogeneous nucleation: A chemical kinetic view (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 84 (1986), S. 416-423 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In classical theory of homogeneous nucleation the flux is derived initially as a function of rate constants for the condensation and vaporization reactions of clusters in the kinetic path. The evaluation of the vaporization rate for clusters of different size is provided by the Thomson–Gibbs relation. In view of discrepancies still existing between measurements and theoretical predictions and the continuing reservations on applying TG relation to microscopic size clusters a different approach is proposed in the present work. A simple function with two undetermined parameters has been used in place of the TR relation to relate the activation energy of the vaporization reaction to cluster size. The parameters are iterated to assume optimum values in numerical computation so experimental data may be correlated. Calculations show this approach closely predicts and correlates available data for water, benzene, and ethanol. The nucleation formulism is redeveloped with an emphasis on the chemical kinetic view. Surface tension of the liquid and free energy of droplet formation are not used in its derivation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450154
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  • 6
    Electronic Resource
    Electronic Resource
    Pharmacological characterization of α2-adrenoceptor-mediated responses in pig nasal mucosa (2003)
    Oxford, UK : Blackwell Science Ltd
    Autonomic & autacoid pharmacology 23 (2003), S. 0 
    Details
    ISSN: 1474-8673
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Chemistry and Pharmacology , Medicine
    Notes: 1 Pig nasal mucosal strips were incubated with α-adrenoceptor antagonists followed by α2-adrenoceptor agonist concentration–response curves. 2 Contractions elicited by the α2-adrenoceptor agonists BHT-920 (pD2 = 6.16 ± 0.07), UK 14,304 (pD2 = 6.89 ± 0.13) and PGE-6201204 (pD2 = 7.12 ± 0.21) were blocked by the α2-adrenoceptor antagonist yohimbine (0.1 μm). In contrast, the α1-adrenoceptor antagonist prazosin (0.03 μm) had no effect on the BHT-920-, UK 14,304- and PGE-6201204-induced contractions, but blocked the contractile response to the α1-adrenoceptor agonist phenylephrine (pD2 = 5.38 ± 0.04) and the mixed α1- and α2-adrenoceptor agonist oxymetazoline (pD2 = 6.30 ± 0.22). 3 The α2-adrenoceptor antagonist yohimbine (0.01–0.1 μm, pA2 = 8.04), α2B/C-adrenoceptor antagonist ARC 239 (10 μm, pKb = 6.33 ± 0.21), α2A/C-adrenoceptor antagonist WB 4101 (0.3 μm, pKb = 8.01 ± 0.24), α2A-adrenoceptor antagonists BRL44408 (0.1 μm, pKb = 6.82 ± 0.34) and RX 821002 (0.1 μm, pKb = 8.31 ± 0.35), α2C-adrenoceptor antagonists spiroxatrine (1 μm, pKb = 7.32 ± 0.32), rauwolscine (0.1 μm, pKb = 8.16 ± 0.14) and HV 723 (0.3 μm, pKb = 7.68 ± 0.14) inhibited BHT-920-induced contractions in pig nasal mucosa. 4 The present antagonist potencies showed correlations with binding affinity estimates (pKi) obtained for these antagonists at the human recombinant α2A- and α2C-adrenoceptors (r = 0.78 and 0.83, respectively) and with binding affinity estimates (pKd) obtained in pig native α2A- and α2C-monoreceptor assays (r = 0.85 and 0.78, respectively). No correlation was observed for the α2B-subtype. 5 In conclusion, contractile responses to phenylephrine, BHT-920, UK 14,304, PGE-6201204 and oxymetazoline indicate that α1- and α2-adrenoceptors are present and mediate vasoconstriction in pig nasal mucosa. Furthermore, correlation analysis comparing antagonist potency in pig nasal mucosa with affinities for human recombinant α2-adrenoceptors and native pig α2-adrenoceptors suggest that α2A- and α2C-adrenoceptor subtypes constrict pig nasal mucosa vasculature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1474-8673.2003.00298.x
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  • 7
    Electronic Resource
    Electronic Resource
    The 50 MeV H− linear accelerator for HERA:LINAC3 collaboration (1991)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 62 (1991), S. 867-873 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The components of the first 50 MeV accelerator in the chain of injectors to the 820 GeV HERA proton ring are described including the high energy transport line. An H− beam originates in the cesium loaded magnetron source, is preaccelerated by a radio frequency quadrupole to 750 keV, raised to 50 MeV energy in three rf resonators, and is analyzed in the transport line. The H− ions are converted to protons by stripping, when the beam is injected over several turns into the synchrotron DESY3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142023
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  • 8
    Electronic Resource
    Electronic Resource
    Laser coloration and bleaching of amorphous WO3 thin film (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 1082-1087 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Laser-induced chromism of amorphous WO3 thin films prepared by pulsed laser deposition (PLD) has been investigated. The original films could be colored from light brown to purple by a single pulse of KrF excimer laser irradiation at 248 nm and subsequently bleached to brown by a single pulse of Nd–yttrium–aluminum–garnet laser at 1.06 μm in air. Spectroscopic investigations were applied to the films at three different states: original, colored, and bleached. The measurements by ellipsometry spectroscopy showed an increase in the refractive index (n) and decrease in extinction coefficient (k) in the luminous range of films from the colored state to the bleached state. Scanning tunneling microscopy and Raman spectroscopy showed slight crystallization in the films after coloration, with both the grain dimension and the surface roughness around tens of nanometers. The films were very stable to maintain the same color after long-time exposure in air, or in oxygen. X-ray photoelectron spectroscopy was used to study the chromism mechanisms. While some W5+ states were introduced in the original films by PLD, W4+ states were produced when the films were colored by the KrF excimer laser, along with the decrease of W5+ states and the increase of W6+ states. In contrast, laser bleaching was accompanied with increasing W4+ states in the films. Therefore, it is believed that the purple color is due to the polaron transition between the W4+ and W5+ states. Photochemical activation and photothermal oxidation are ascribed to the coloring and the bleaching processes, respectively. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373780
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  • 9
    Electronic Resource
    Electronic Resource
    Electrochromic writing and erasing on tungsten oxide films in air by scanning tunneling microscopy (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 440-443 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The scanning tunneling microscope (STM) was used for both spot coloring and bleaching on α-WO3−x thin films. By wetting the STM tip with 1 M KOH solutions or de-ionized water before the tip approached, and keeping the humidity higher than 40%, the electrochemical reaction occurred at the tip–surface gap while the electrochromic reactions took place at the film surface. With a constant negative sample bias and grounded tip, a brown color circle or a light blue disk was formed on the surface with an enlarged diameter. The circle and disk formations were attributed to the production of alkali and hydrogen tungsten bronzes. By applying a positive sample bias with a grounded tip, the color of the hydrogen tungsten bronze could be bleached. The cathodic reduction of W6+ forms a color center at the W5+ site, while the anodic reaction removes an electron from the color center W5+ state. Raman spectroscopy indicated that for the colored state, the frequency for the W–O bond stretching mode increased, while for the W(Double Bond)O bonds it decreased. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1424053
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  • 10
    Electronic Resource
    Electronic Resource
    Investigation of Li-doped ferroelectric and piezoelectric ZnO films by electric force microscopy and Raman spectroscopy (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 79 (2001), S. 812-814 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have grown Li-doped ZnO films on silicon (100) using the rf planar magnetron sputtering method. The surface charges induced piezoelectrically by defect and by polarization can be observed by electric force microscopy. The Li-doped ZnO films have been proven to be ferroelectric. The Raman spectra of ZnO and Li-doped ZnO films have been measured. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1391225
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