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  • 1
    Electronic Resource
    Electronic Resource
    Surface-enhanced Raman scattering from p-nitrobenzoic acid (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 1150-1155 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The surface-enhanced Raman scattering (SERS) from thin films formed by p-nitrobenzoic acid (PNBA) adsorbed onto silver island films has been investigated. SERS spectra obtained using low laser powers were very similar to the normal Raman spectra of the sodium salt of PNBA and were characterized by strong bands near 1600 and 1355 cm−1 and by weaker bands near 1395, 1115, and 875 cm−1. The band near 1395 cm−1 was assigned to the symmetric stretching mode of carboxylate groups, indicating that PNBA was adsorbed as a metal salt. When PNBA films were irradiated at high laser powers, a rapid reaction occurred. The bands near 1355 and 1115 cm−1 gradually decreased in intensity and a strong band near 1460 cm−1 and a strong doublet near 1150 cm−1 gradually appeared. The band near 1460 cm−1 and the doublet near 1150 cm−1 were attributed to azodibenzoate formed by the reductive coupling of PNBA molecules at the silver surface during laser irradiation. When adsorbed PNBA films were irradiated at low laser powers, the reaction still occurred but at a much lower rate. Reduction of PNBA was probably thermally induced but a photochemical mechanism may also be possible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451311
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  • 2
    Electronic Resource
    Electronic Resource
    Temperature measurements behind shock waves using a rapid scanning IR-diode laser (1987)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 30 (1987), S. 1294-1298 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Temperature measurements behind shock waves are possible by applying optical methods. In the case of a thermally relaxing system it is generally difficult to measure the translational and vibrational temperatures separately and in a direct way. In the present case, a rapid scanning infrared-diode laser has been used to study the relaxation behavior of a shock heated CO/Ar mixture. The vibrational temperature can be measured by rapid scanning over two or three adjacent rotational lines from different vibrational transitions of CO. In addition it is possible to determine the translational temperature of the gas mixture from the thermal broadening of a single highly resolved rotational absorption line. The experimentally determined vibrational and translational temperature are in reasonable agreement with the computed values based on shock speed measurements and vibrational relaxation data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.866244
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  • 3
    Electronic Resource
    Electronic Resource
    A capacitance displacement sensor with elastic diaphragm (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 2051-2053 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have developed a capacitance displacement sensor based on the elastic deformation of a 150 μm thick diaphragm made up of Cu0.98Be0.02. Displacements up to 50 μm can be detected. The resolution is about 0.1 nm. The time dependence of the dilatation of a relaxor-ferroelectric (Sr0.61Ba0.39)Nb2O6 single crystal after removing an electric field is investigated using this sensor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143165
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  • 4
    Electronic Resource
    Electronic Resource
    Determination of biokinetic parameters for ingestion of radionuclides of zirconium in animals using stable tracers (2000)
    Springer
    Radiation and environmental biophysics 39 (2000), S. 53-58 
    Details
    ISSN: 1432-2099
    Keywords: Key words Biokinetics ; Internal dose ; Intestinal absorption ; Stable tracers ; Zirconium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract  Exposure to the radioactive isotope 95Zr, as in nuclear accidents, and to stable zirconium, due to its use in industry, has increased the interest in the biokinetics of this element. Information has been derived mainly from tests performed on animals by means of radioactive tracers. Due to the fact that extrapolation from animals to humans is always open to question, there is an increasing need of a methodology which allows data to be obtained directly from humans. The use of stable tracers, being ethically justifiable, is a powerful tool for providing this information. As two tracers of the same element must be utilized in order to evaluate gut absorption, an analytical technique which is capable of distinguishing and measuring simultaneously different isotopes of zirconium in biological samples is required. Preliminary tests on laboratory animals were performed in order to assess the feasibility of the double tracer technique combined with proton activation analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00007687
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  • 5
    Electronic Resource
    Electronic Resource
    A shock tube study on the thermal decomposition of CS2 based on S(3P) and S(1D) concentration measurements (1994)
    Springer
    Shock waves 4 (1994), S. 95-99 
    Details
    ISSN: 1432-2153
    Keywords: ARAS ; Chemical shock tube ; Thermal decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics , Technology
    Notes: Abstract The thermal decomposition of CS2 highly diluted in Ar was studied behind reflected shock waves by monitoring time-dependent absorption profiles of S(3P) and S(1D) using atomic resonance absorption spectroscopy (ARAS). The rate coefficient of the reaction: (R1) $$\begin{gathered} CS_2 + M\mathop \to \limits^{k_1 } CS + S + M, \hfill \\ k_1 = 5.1 \times 10^{14} \exp \left( {\frac{{ - 38150K}}{T}} \right)cm^3 mol^{ - 1} s^{ - 1} \hfill \\ \end{gathered} $$ . was determined in experiments with initial concentrations of CS2 between 5 and 50 ppm at post-shock conditions of 2300 K≤T≤3360 K and total densities between 2.2×1018 cm−3 and 3.9×1018 cm−3. In experiments with higher initial concentrations of 100 ppm CS2 in Ar, the S(3P) concentrations were found to reach quasi-stationary values. From the steady state assumption a value for the rate coefficient of the most probable S consuming reaction: (R2) $$\begin{gathered} CS_2 + S\mathop \rightleftharpoons \limits^{k_2 } CS + S_2 , \hfill \\ k_2 \approx 1.2 \times 10^{13} cm^3 mol^{ - 1} s^{ - 1} \hfill \\ \end{gathered} $$ . was estimated at temperatures between 2100 K and 2340 K.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01418572
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  • 6
    Electronic Resource
    Electronic Resource
    Numerical modelling of detonation structure in two–phase flows (1996)
    Springer
    Shock waves 6 (1996), S. 17-20 
    Details
    ISSN: 1432-2153
    Keywords: Key words:Detonation, Heterogeneous flows, Particle oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics , Technology
    Notes: Abstract. A one-dimensional physical model and a numerical method for the simulation of heterogeneous detonation were proposed based on an Eulerian approach for heterogeneous flows. The combination of modern shock-capturing schemes in combination with a dynamically moving, adaptive grid ensure the properresolution of both reaction zones and flow discontinuities. Numerical examples illustrate the effect of the heat release due to heterogeneous combustion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001930050015
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  • 7
    Electronic Resource
    Electronic Resource
    Measurement of O( $^1$ D) formation during thermal decomposition of CO $_2$ behind shock waves (1996)
    Springer
    Shock waves 6 (1996), S. 79-83 
    Details
    ISSN: 1432-2153
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics , Technology
    Notes: Abstract. Atomic Resonance Absorption Spectroscopy (ARAS) was applied to measure the time dependent concentration of electronically excited O( $^1$ D)-atoms during the thermal decomposition of CO $_2$ behind reflected shock waves. The experiments were performed in the temperature range 4102 K $ \le $ T $ \le $ 6375 K at pressures 0.2 to 1.9 bar with initial gas mixtures of 100 to 1000 ppm CO $_2$ diluted in Ar. The measured O( $^1$ D)-formation rate at early reaction times divided by the initial reactant concentrations was found to obey the Arrhenius law: \beo &&\frac{d[{\rm O(^1D)}]/dt}{{\rm [CO_2]_0 \, [Ar]}} \Biggr|_{t \approx 0} \\ &&\quad = 1.23 \times 10^{14} \exp \left( -74810 {\rm K}/T \right){\rm cm^{3} mol^{-1} s^{-1}} \eeo The assumption of a fast thermalisation between the O( $^3$ P) and O( $^1$ D) states is in agreement with previous measurements of the O( $^3$ P) formation during the thermal decomposition of CO $_2$ , see Burmeister and Roth (1990).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001930050023
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  • 8
    Electronic Resource
    Electronic Resource
    IR-diode laser measurements on the decomposition of NO behind shock waves (1992)
    Springer
    Experiments in fluids 13 (1992), S. 299-304 
    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 The decomposition of NO diluted in Ar was measured in the temperature range 2,500 K ⩽ T ⩽ 3,500 K at pressures between 0.5 and 1.9 bar using the shock tube method. The gas mixtures containing 10 to 25% NO in Ar were shock heated and the time-dependent NO concentrations were monitored by using a tunable IR-diode laser. The measured NO concentration profiles in the post-shock reaction zone were interpreted by means of computer simulations. With a reaction mechanism developed by Thielen and Roth (1984) nearly complete agreement between calculated and measured NO concentration profiles was obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209501
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  • 9
    Electronic Resource
    Electronic Resource
    First observations on break-up of particle agglomerates in shock waves (1987)
    Springer
    Experiments in fluids 5 (1987), S. 86-94 
    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 The destruction of solid agglomerates suspended in argon by means of shock waves (1 〈M s 〈 5) has been studied experimentally using a conventional shock tube apparatus. The change in particle size was measured by time-dependent in situ laser light scattering of the particle ensemble in the shock wave. The test facilities used are given in details, and the principle of the Mie-theory, necessary for complete understanding of the data reduction, is described. In this paper data reduction and first analysis employing two independent trial solutions involving the Mie-theory for polydisperse, spherical particle-ensembles are presented. Three types of agglomerates suspended in argon with a mean initial size of about 1 gm were exposed to the shock wave and different size reduction behaviours were observed. The deagglomeration effect depends largely on the wave intensity and on the physico-chemical structure of the particle aggregates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00776178
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  • 10
    Electronic Resource
    Electronic Resource
    Stoßwellen in Gas-Partikel-Gemischen mit Massenaustausch zwischen den Phasen (1985)
    Springer
    Heat and mass transfer 19 (1985), S. 101-111 
    Details
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Die Nichtgleichgewichts-Austauschprozesse, die in einem Gas-Partikel-Gemisch hinter einer Stoßwelle ablaufen, werden in dieser Arbeit untersucht. Sie werden sowohl mit den Erhaltungsgleichungen für zwei interaktive Kontinua als auch mit den vereinfachten Gleichungen für Einzelpartikel in einem Gaskontinuum beschrieben. Der besondere Akzent liegt auf den Transportvorgängen sehr kleiner Partikel, die im Übergangsbereich zwischen Kontinuumsbedingungen und freier Molekülströmung stattfinden. Sie werden durch einfache Knudsenzahlansätze berücksichtigt. Beispiele zeigen die Geschwindigkeits-, Temperatur- und Partikelgrößenrelaxation hinter Stoß-wellen in Argon mit DOP-Tröpfchen und mit festen NaCl-Salzpartikeln.
    Notes: Abstract The nonequilibrium transfer processes, which take place in a gas-particle mixture behind shock waves, are investigated in this study. They will be described both by the conservation equations of two interactiv continua and by the simplified equations of a single particle in a gas continuum. The special accent is on exchange processes of very small particles, which take place in the transition regime between continuum and free molecular conditions. They are taken into account by simple Knudsen number corrections. Examples show the velocity, the temperature and the particle size relaxation behind shock waves in argon containing DOP droplets or solid NaCl particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01682553
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