Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 61.70.Tm  (1)
  • Laboratory simulations  (1)
  • 1
    ISSN: 1432-0630
    Keywords: 44.90.+c ; 61.16.Di ; 61.70.Tm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Rutherford backscattering (RBS), ion channeling and surface studies were done to investigate diffusion of ion implanted Sb in Si. Clean and polished Si was implanted by 190KeV Sb+ ions to a dose of 2.3×1015cm−2. Laser annealing was carried out by a single 10 J/cm2 laser pulse from a Nd: glass (7 ns FWHM) laser. Concentration profiles of Sb as a function of depth and dopant substitutionalities were measured by helium-ion backscattering and channeling. The laser shot resulted in melting of the central portion of the spot. A honey comb type surface morphology was found by SEM analysis. Dektak surface profiles showed a crater of 600 nm depth. One-dimensional heating calculations show that dopant diffusion depths, after consideration of simultaneous evaporation, can be ∼400 nm, whereas experiments indicate larger depths (∼1 μm). Calculated crater depth is roughly twice the experimental value. Measured depths are much larger than calculated by heat diffusion and indicate that regrowth and distribution of Sb has been modified by convection in the melt. We estimate good substitutionality up to 4 J/cm2 and discuss energy density dependence for such high-energy density laser pulses.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of volcanology 57 (1995), S. 229-239 
    ISSN: 1432-0819
    Keywords: Key words Lava dome ; Lava flow mechanisms ; Laboratory simulations ; Mt St Helens ; Soufrière of ; St Vincent ; Venus volcanism ; Pancake domes ; Planetary volcanism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  To better understand the factors controlling the shapes of lava domes, laboratory simulations, measurements from active and prehistoric flows and dimensional analysis were used to explore how effusion history and cooling rate affect the final geometry of a dome. Fifty experiments were conducted in which a fixed volume of polyethylene glycol wax was injected into a tank of cold sucrose solution, either as one continuous event or as a series of shorter pulses separated by repose periods. When the wax cooling rates exceeded a critical minimum value, the dome aspect ratios (height/diameter) increased steadily with erupted volume over the course of a single experiment and the rate at which height increased with volume depended linearly on the time-averaged effusion rate. Thus the average effusion rate could be estimated from observations of how the dome shape changed with time. Our experimental results and dimensional analyses were compared with several groups of natural lava flows: the recently emplaced Mount St Helens and Soufrière domes, which had been carefully monitored while active; three sets of prehistoric rhyolite domes that varied in eruptive style and shape; and two sets of Holocene domes with similar shapes, but different compositions. Geometric measurements suggest that dome morphology can be directly correlated with effusion rate for domes of similar composition from the same locality, and that shape alone can be related to a dimensionless number comparing effusion rate and cooling rate. Extrapolation to the venusian 'pancake domes' suggests that they formed from relatively viscous lavas extruded either episodically or at average effusion rates low enough to allow solidified surface crust to exert a dominating influence on the final morphology.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...