| 1. |
- Levin, J.C., et al.
(författare)
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Production of very cold, highly charged ions by synchrotron radiation: Comparisons of the “scalpel” and “hammer” methods
- 1987
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 262:1, s. 106-109
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of kinetic energies of highy charged argon ions produced by inner-shell photoionization and by ion-beam impact have been made using time-of-flight techniques. High-charge-state recoil ions produced by beams of ∼ 0.5-1 MeV/u Cl5+ are found to have energies one to two orders of magnitude higher than ions of the same charge produced by vacancy cascades following inner-shell photoionization by synchrotron radiation. The results may have application to the development of a very cold ion source useful for angle-resolved atomic collision studies.
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| 2. |
- Short, R. T., et al.
(författare)
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Production of very-low-energy highly charged ions by synchrotron radiation
- 1986
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Ingår i: Physical Review Letters. - 1079-7114. ; 56:24, s. 2614-2617
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Tidskriftsartikel (refereegranskat)abstract
- Very-low-energy highly charged ions have been produced by use of white and monochromatic x rays from a wiggler line at the Stanford Synchrotron Radiation Laboratory to generate vacancy cascades following inner-shell photoionization. Recoil-ion energies have been determined and are shown to correspond essentially to room temperatures, even for high charge states. Promising applications to study of the interaction of stellar radiation with cold matter, to high-brightness ionsource development, to precision spectroscopy, and to angle-resolved chemical-physics reactive-scattering studies are discussed.
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| 3. |
- Plos, Kaety, 1944, et al.
(författare)
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Distribution of the P-associated-pilus (pap) region among Escherichia coli from natural sources: evidence for horizontal gene transfer.
- 1989
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Ingår i: Infection and immunity. - 0019-9567. ; 57:5, s. 1604-11
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Tidskriftsartikel (refereegranskat)abstract
- Variation in chromosomal DNA in Escherichia coli was studied with probes specific for the P-associated-pilus (pap) region. The presence of DNA homologous to pap was determined by dot blots. Variation in the number of copies of pap and in the organization of internal and flanking sequences was determined by Southern blot hybridization. The 229 strains studied were also classified by O:K:H serotyping and multilocus enzyme electrophoresis. There was considerable heterogeneity in the presence of pap and distribution of pap-homologous DNA in these E. coli strains from natural sources. In general, there was less variation in pap among strains of the same specific O:K:H serotype and enzyme electrophoretic type than among random isolates. There were, however, E. coli strains identified as members of the same clone by O:K:H serotyping and enzyme electrophoresis that were pap positive and pap negative or had different Southern blot patterns for the pap probes (pap type). There were also isolates of the same pap type that differed in two of three O:K:H serotype antigens and the majority of enzymes that determined their enzyme electrophoretic type. These latter two observations were interpreted as evidence for the horizontal (infectious) transfer of the pap-homologous sequences among clones of E. coli.
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