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  • 34.70  (3)
  • 32.80B  (1)
  • Angiography  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Registered image subtraction for CT-, MR- and coronary angiography (1997)
    Springer
    European radiology 7 (1997), S. 82-89 
    Details
    ISSN: 1432-1084
    Keywords: Key words: Image registration ; Image subtraction ; DSA ; Image processing ; Angiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Conventional post-processing of digital subtraction angiography (DSA) by 3D spiral CT, 3D MRI and 2D DSA is often hampered by extended artefacts due to patient movements during examination. In this paper an image registration procedure prior to the digital subtraction is introduced allowing an enhanced visualization of the contrast agent. The object displacement is detected by analysis of image deformations in small local regions. The motion pattern is used to compute a new synthetic mask of maximum congruence with the contrast medium image. This new mask image is then used in the subsequent subtraction. The algorithm works fully automatically and does not need any interactive placement of landmarks. Results obtained from subtraction of uncorrected and corrected sequences were compared with each other. The registration procedure provided good results in the suppression of subtraction artefacts and in the enhancement of vascular structures. Results are presented from subtraction of 2D and 3D data from CTA, MR mammography and coronary angiography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003300050115
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Polarisation effects in electron transfer reactions with laser excited Na(3P) at medium energies (1994)
    Springer
    The European physical journal 30 (1994), S. 211-215 
    Details
    ISSN: 1434-6079
    Keywords: 34.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report new experimental data for the investigation of the role of electronic orbital alignment and orientation in charge transfer processes, in the medium energy range where the collision velocityv c and the velocity of the active electronv e are of the same order of magnitude. The results obtained for the H 2 + -Na(3p) and He+-Na(3p) collisions are discussed in comparison with the experimental and theoretical findings obtained for the H+-Na(3p) system. Recent time-of-flight measurements for charge transfer in Li+-Na(3s and 3p) collisions are also presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426075
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Collision spectroscopy with aligned and oriented atoms (1991)
    Springer
    The European physical journal 18 (1991), S. 231-234 
    Details
    ISSN: 1434-6079
    Keywords: 34.00 ; 34.70 ; 32.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Neutralisation processes in 0.15–1.5 keV collisions of H− with Na atoms in the 3s ground state or in the excited 3p state have been investigated by means of time-of-flight analysis of the neutral H atoms produced. The H− - Na(3p) system, investigated here for the first time, is particularly interesting since the entrance channel is embedded in the [H - Na(3s)] +e − continuum, enabling Penning detachment to occur. The measured relative neutralisation cross section ratios σ(3p)/σ(3s) decrease from 3 to 1.6 with increasing energy. Based on earlier published results for σ(3s), σ(3p) total cross sections exceeding 100 Å2 are estimated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01437076
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Alignment and orientation effects in resonant charge exchange from laser excited Na*(3p) (1987)
    Springer
    The European physical journal 5 (1987), S. 101-111 
    Details
    ISSN: 1434-6079
    Keywords: 32.80B ; 34.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A collisional alignment and orientation study with planar symmetry is described, determining the complete density matrix for resonant charge transfer from laser excited atoms. Results are reported for the Na++Na*(3p) system over the collision energy rangeE c.m.=50−100 eV. We communicate the optimal alignment angle γ and linear polarisationP l + of the charge cloud as well as its relative height ρ00 and the angular momentumL ⊥ + transferred in the collision as a function of the scattering angle. For preparation of the sodium 3p orbital in the scattering plane (positive reflection symmetry) we observe that at small reduced scattering angles (〈20 eV°) the preparation of apσ at large internuclear distances contributes most to the scattering intensity whereas at larger reduced scattering angles (〉60 eV°) apπ+ preparation is more important. In contrast, preparation of thepπ− orbital (perpendicular to the scattering plane) is large at small and vanishes at larger scattering angles. We conclude that orbital following cannot be assumed in this resonant charge transfer process. The angular momentum transfer is observed to be small, indicating only little coherence in the process, but shows nevertheless an interesting behaviour as a function of scattering angle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01436884
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    Paper (German National Licenses)
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