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  • 1985-1989  (3)
  • 1
    ISSN: 1434-601X
    Keywords: 29.20 ; 41.80.D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The first results are presented of electron cooling experiments in the Low-Energy Antiproton Ring (LEAR) at CERN, performed with a proton beam of about 50 and 21 MeV. The number of stored protons ranged from 107 to 3 × 109. Cooling times of the order 1 s and proton drag rates of up to 0.7 MeV/s were obtained. The capture of cooling electrons by protons producing hydrogen atoms was used to derive an effective electron temperature (0.25 eV). From the angular profile of the neutral hydrogen beam an upper limit of 3π mm.mrad could be deduced for the horizontal equilibrium proton-beam emittance. The lowest equilibrium momentum spread was 2 × 105 (FWHM), as derived from the analysis of the longitudinal Schottky signal. This Schottky signal exhibited an unusual behaviour with beam intensity and under certain conditions showed a doublepeak structure which was associated with collective beam noise. For very cold beams transverse instabilities were observed, which resulted in a rapid spill-off of protons and a stabilization at lower intensities. The threshold of these instabilities was raised by heating the proton or the electron beam. The cooling of a bunched proton beam was investigated. The reduction of the proton momentum spread led to bunch lengths of about 2 m, containing 3 × 108 protons.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-2630
    Keywords: digital subtraction angiography ; orbital and ocular circulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In serial experiments on cats, intravenous digital subtraction angiography (DSA) was utilized to observe orbital and ocular circulation. Images of the orbital arterial system as well as normal ocular vasculature were obtained, utilizing dosage of contrast material acceptable for human study. Images obtained after intraarterial DSA had no advantage over those obtained with intravenous DSA. After retrobulbar injection of 3 ml of saline, intravenous DSA demonstrated straightening of the external ophthalmic arteries showing the potential of this method for identifying orbital vascular pathology.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Water, air & soil pollution 34 (1987), S. 325-338 
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A study was undertaken to examine whether ‘acid pulses’ from snowmelt created permanent changes in a pond's chemistry. Water samples were collected from clearwater acidic Cone Pond in the White Mountain National Forest, New Hampshire. The pond, inlet, and outlet were intensively sampled throughout winter and early spring 1983–84. Thaws brought more H+ into upper waters of the pond, but most was gone within a week. In contrast, SO4 2− and Al showed dilution with increased streamflow into the pond, and NO3 − was only detected in ice, slush, and surface waters. Bottom waters were anoxic throughout the winter and had pH 6.0 compared to 4.7 for most of the water column. Alkalinity at the bottom rose from 0 in November 1983 to 190 μeq L−1 in April 1984. Between November and April the pond gained Al but lost SO4 2− and H+. Most of the Al gain came after ice-out when loading through the inlet increased, but during the final snowmelt a temporary increase in Al concentration was also seen throughout the water column.
    Type of Medium: Electronic Resource
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