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  • 1
    Digitale Medien
    Digitale Medien
    Theoretical and experimental studies of CO2 laser evaporation of clouds (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 4601-4616 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A study of the effects of laser radiation on cloud drops and of the possibility of producing a clear optical channel in a cloud is presented. In order to produce a model that is appropriate to a realistic cloud with a distribution of drop sizes it is first necessary to study what happens to a single water drop subjected to laser radiation of different intensities. Various heating regimes are mapped out as a function of laser flux and fluence at the 10.6 μm wavelength. It is found that typical cloud drops can superheat until they become unstable and explode from the center. For a long laser pulse the boundary for this to occur is found to be 50(5/r)2 kW/cm2, where r is the drop radius in microns. Using these results a model that is spatially one-dimensional through the cloud is constructed for a distribution of drop sizes. Laser beam intensity as the light penetrates a cloud is calculated from Mie scattering and absorption cross sections for a beam diameter that is small in the sense that light scattered once is assumed lost. The internal temperature distribution of the drops is calculated and a phenomenological drop explosion model is given for drops that reach the unstable 305 °C spinodal temperature at their center. Energy and water mass content are conserved as the cloud background is modified in an average sense by drop evaporation or recondensation. Recondensation is treated in the diffusion regime according to the Kohler model, with vapor pressure over a drop modified by surface tension and dissolved nonwater content. Comparison with experimental data for a laboratory produced cloud is given and good agreement, particularly with respect to the predicted onset of drop explosion, is found. Results are also presented for hypothetical cloud conditions and laser intensities. The possibility of clearing a thin cloud with low fluence to the 3.8 μm is considered, as well as the passive evaporation of melted ice crystal clouds.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.349097
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  • 2
    Digitale Medien
    Digitale Medien
    The measurement of quality of life in young children (2000)
    Oxford, UK : Blackwell Science Ltd
    Child 26 (2000), S. 0 
    Details
    ISSN: 1365-2214
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin , Psychologie
    Notizen: The purpose of this paper is to argue for a measure of quality of life (QoL) for children aged between 4 and 8 years, describe the obstacles in developing such a measure, and provide evidence that it is possible to elicit directly information from children. Finally we summarize and critique measures that are currently available for this purpose.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-2214.2000.00154.x
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  • 3
    Digitale Medien
    Digitale Medien
    Collisional transport treatment of surface plasma structures (1989)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 1 (1989), S. 1911-1925 
    Details
    ISSN: 1089-7666
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Calculations are shown of the structure of plasmas in equilibrium with solid surfaces that reemit incident plasma ions as relatively cold neutral gas. A numerical transport model that includes a Fokker–Planck treatment of ion–ion collisions obtains the distribution function for ions in a phase space of one spatial coordinate and two velocities. This is done self-consistently with an electrostatic potential, a Maxwell–Boltzmann description of electrons, and electron impact ionization of the reemited neutrals. Solutions are obtained from a higher temperature kinetic regime where Coulomb collisions are nearly negligible to a lower temperature regime where plasma behavior is approximately fluidlike. A result of these calculations is the resolution of an ambiguity posed by previous kinetic regime calculations that omitted ion–ion collisions and obtained a family of solutions for each set of physical parameters [Phys. Rev. Lett. 49, 650 (1982); Phys. Fluids B 1, 448 (1989)]. The physically correct solution for semi-infinite surface plasmas is shown to be the member of each family that maximizes the ion thermal conduction to the surface and the magnitude of a maximum in the electrostatic potential that is found in these and the previous calculations. Further results are in agreement at lower temperatures with solutions obtained from a fluid model and the identification of the correct boundary condition on normal flow velocity to be used in fluid models.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.858923
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  • 4
    Digitale Medien
    Digitale Medien
    Self-consistent growth rate of the Rayleigh–Taylor instability in an ablatively accelerating plasma (1985)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 28 (1985), S. 3676-3682 
    Details
    ISSN: 1089-7666
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The linear stability of an ablating plasma is investigated as an eigenvalue problem by assuming the plasma to be at the stationary state. For various structures of the ablating plasma, the growth rate is found to be expressed well in the form γ=α(kg)1/2 −βkVa, where α=0.9, β(approximately-equal-to)3–4, and Va is the flow velocity across the ablation front, and is found to agree well with recent two-dimensional simulations in a classical transport regime. Short-wavelength lasers inducing enhanced mass ablation are suggested to be advantageous to stable implosion because of the ablative stabilization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.865099
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  • 5
    Digitale Medien
    Digitale Medien
    Fluid model treatment of surface plasma structures (1992)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 4 (1992), S. 784-795 
    Details
    ISSN: 1089-7666
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A fluid model is presented for the purpose of calculating numerically the structures of surface plasmas with neutrals returning from the surface, in collision-dominated parameter regimes. Limiting corrections to thermal conduction and viscous pressure are obtained through comparisons with previous Fokker–Planck transport calculations. The model includes removal by pumping, as well as by ionization, of some of the returning neutrals, and solutions are obtained for different relative strengths of pumping. Increasing velocities of plasma flow toward the surface and increasing plasma temperatures near the surface are seen with increased pumping. In the asymptotic region, far from the surface, agreement is found between these families of numerical model solutions and two classes of analytic solutions. Applications to other fundamental and applied problems are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.860233
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  • 6
    Digitale Medien
    Digitale Medien
    Surface plasma structures in the kinetic regime (1989)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 1 (1989), S. 448-467 
    Details
    ISSN: 1089-7666
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A numerical study is done of a plasma in contact with a solid surface that reemits some fraction of the incident plasma as neutral gas. The calculation uses a steady-state, kinetic treatment of the transport equations in one space dimension and one or two velocity dimensions to determine self-consistently the distribution functions of the interacting species and the electrostatic potential. The dominant phenomena are the ionization of the neutral gas and the acceleration of the resulting ions away from a potential maximum that is predicted to form in the ionization region. Other effects involved are a Debye sheath structure between the solid surface and the potential maximum, and collisional trapping and untrapping of electrons in the well represented by the potential maximum. Results are presented from a nondimensional model with a monatomic returning neutral species, and for diatomic molecular deuterium returning from the surface. For each set of physical parameters chosen, a one parameter family of solutions is obtained. A hypothesis is presented for the choice from this family of solutions that would be found experimentally.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.859160
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  • 7
    Digitale Medien
    Digitale Medien
    Submicroanalysis by Radiochromatography. (1964)
    s.l. : American Chemical Society
    Analytical chemistry 36 (1964), S. 2350-2350 
    Details
    ISSN: 1520-6882
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ac60218a001
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  • 8
    Digitale Medien
    Digitale Medien
    Sonic Energy in Granular Solid Fluidization (1955)
    s.l. : American Chemical Society
    Industrial & engineering chemistry 47 (1955), S. 1170-1175 
    Details
    ISSN: 1520-5045
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ie50546a023
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  • 9
    Digitale Medien
    Digitale Medien
    Mite Pests of Honey Bees (1982)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Entomology 27 (1982), S. 229-252 
    Details
    ISSN: 0066-4170
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.en.27.010182.001305
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  • 10
    Digitale Medien
    Digitale Medien
    Stationary flow model of ablatively imploded spherical shells (1990)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 2 (1990), S. 353-370 
    Details
    ISSN: 1089-7666
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The stationary flow model of spherical ablation is extended to shells, solutions with a density discontinuity at the critical surface, and charged-particle-beam-driven ablation. Parameter studies of the shell solutions show the relationship between shell aspect ratio, relative ablative mass removal or burnthrough, laser power, and shell material type. The discontinuous solutions are shown to occur when the critical surface and sonic surface coalesce. The relationship of these discontinuous solutions to particular physical situations is shown to be ambiguous in a way that must be resolved by microscopic transport calculations. Charged-particle-driven ablative implosion processes are shown to resemble laser-driven ablation. However, qualitatively different ablation processes occur in different regimes of the power and particle range of the incident beam. Procedures are described by which stationary solutions can be used to predict and interpret the results of experiments and numerical simulations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.859324
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