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| 2. |
- CRISTANCHO, F, et al.
(författare)
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MULTIPLE SUPERDEFORMED BANDS IN SR-81
- 1995
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Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 357:3, s. 281-286
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Tidskriftsartikel (refereegranskat)abstract
- Four superdeformed bands extending over five to twelve transitions have been identified in Sr-81 from a study With the Gammasphere array and the Microball charged-particle array, One of the bands shows an upbend in the dynamic moment of inertia at a rotational frequency of 1.2 MeV and all bands exhibit a nearly constant moment of inertia below that frequency.
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| 3. |
- JIN, HQ, et al.
(författare)
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IDENTIFICATION AND QUADRUPOLE-MOMENT MEASUREMENT OF A SUPERDEFORMED BAND IN ZR-84
- 1995
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 75:8, s. 1471-1474
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Zr-84 were studied using the early implementation phase of the Gammasphere array and the ''Microball'' charged-particle detector system. A cascade of nine gamma rays with a dynamic moment of inertia which is characteristic of superdeformed rotational bands in the A = 80 region has been identified and assigned to Zr-84. The measured transition quadrupole moment of the band corresponds to a prolate quadrupole deformation of beta(2) = 0.53 and confirms the superdeformed nature of this band. This is the first direct experimental confirmation of the existence of the predicted superdeformed shell gap at N similar or equal to 44 particle number.
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| 4. |
- LAFOSSE, DR, et al.
(författare)
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CHARACTERIZATION OF THE FIRST SUPERDEFORMED BAND IN THE A-APPROXIMATE-TO-80 REGION
- 1995
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Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 354:1-2, s. 34-40
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Tidskriftsartikel (refereegranskat)abstract
- The recently discovered superdeformed band in one of the strontium isotopes has been identified as belonging to Sr-83 from a study with the Gammasphere array and the Microball charged-particle detector system. From its decay pattern, a spin of (81 +/- 2)/2 ($) over bar h is deduced for the highest level of this band. Evidence for very fast transition rates and agreement of the characteristics of this band with the theoretical predictions establish the yrast superdeformed nature of this band in Sr-83.
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| 5. |
- LAFOSSE, DR, et al.
(författare)
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EVIDENCE FOR HYPERDEFORMATION IN GD-147
- 1995
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 74:26, s. 5186-5189
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Laihonen, Sari J., et al.
(författare)
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Crystal structure and morphology of melt-crystallized poly(propylene-stat-ethylene) fractions.
- 1997
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Ingår i: Polymer. - 0032-3861 .- 1873-2291. ; 38:2, s. 371-377
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Tidskriftsartikel (refereegranskat)abstract
- Crystallinity, crystal structure and lamellar thickness in melt-crystallized samples of poly(propylene-stat-ethylene) fractions with 2.7–11.0 mol% ethylene comonomer and of approximately constant tacticity were assessed by wide- and small-angle X-ray scattering, differential scanning calorimetry and infra-red spectroscopy. Most of the samples were crystallized under isothermal conditions at 373 K. In comparison with an isotactic homopolymer of polypropylene, the copolymers showed lower crystallinity, melting enthalpy and average length of 3/1 helices, a slightly larger unit cell, a longer long period and an invariant lamellar thickness. The X-ray crystallinity of the copolymers remained approximately constant with increasing ethylene content, whereas the γ-crystallinity increased and the heat of fusion decreased moderately. It is suggested that the ethylene units are partially included in the crystals, and that this causes the invariance in crystallinity and crystal thickness. The observed gradual decrease in average 3/1 helix length with increasing ethylene content as assessed by infra-red spectroscopy is in accordance with this suggestion.
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| 7. |
- Laihonen, Sari J., et al.
(författare)
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Crystallization kinetics and morphology of poly(propylene-stat-ethylene) fractions.
- 1997
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Ingår i: Polymer. - 0032-3861 .- 1873-2291. ; 38:2, s. 361-369
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Tidskriftsartikel (refereegranskat)abstract
- The crystallization and melting behaviour and the morphology of fractions of poly(propylene-stat-ethylene) with 2.7–11.0 mol% ethylene were studied by differential scanning calorimetry, wide-angle X-ray scattering, polarized light microscopy and transmission electron microscopy, after etching with permanganic acid. The inclusion of ethylene co-repeating units in isotactic polypropylene (0–11.0 mol% ethylene) caused approximately linear decreases in kinetic and equilibrium melting temperatures and in the glass transition temperature with increasing ethylene content. X-ray scattering showed that the content of the γ form increased with increasing ethylene content, increasing crystallization temperature and decreasing cooling rate from the molten state. It was shown for one of the copolymers (8.7 mol% ethylene) that during heating approximately 50% of the γ form was converted to the α form before the final melting of the sample. The rest of the γ crystals melted without transformation to the α form. The multimodality of the crystal melting above the crystallization temperature in the polymers with a more uniform crystal structure was caused by recrystallization during heating, whereas polymers with appreciable contents of both α and γ forms exhibited multimodal melting at all the heating rates adopted. The size of the low temperature melting peak as assessed at a heating rate of 40 K min−1 was approximately proportional to the initial content of the γ form. By comparison with the spherulitic structure of homopolymers, that of the copolymers was coarser with internal and peripheral pockets of molten material during spherulite growth. The crystal lamellae exhibited more curvature in the copolymer samples than in the homopolymer.
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