| 1. |
- Fynbo, H. O. U., et al.
(författare)
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News on C-12 from beta-decay studies
- 2004
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 738, s. 59-65
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Konferensbidrag (refereegranskat)abstract
- We discuss the importance of the spectroscopic properties of the resonances of C-12 just above the 3alpha-threshold, and review the existing experimental information of this region with emphasis on 0(+) and 2(+) states. A new experimental approach for studying the beta-decays of B-12 and N-12 is presented based on techniques developed in the context of Radioactive beam (rare isotope) physics. Finally preliminary results from an ongoing analysis of two recent experiments are given.
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| 2. |
- Borge, M. J. G., et al.
(författare)
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Beta-delayed multiparticle emission studies at ISOL-type facilities
- 2004
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 746, s. 243-243
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Konferensbidrag (refereegranskat)abstract
- We report here on the recent beta-decay studies made at ISOL-type Facilities to determine the multiparticle breakup mechanism of excited states in light nuclei by studying them in full kinematics. In particular the results obtained for the A = 9 isobars and the breakup of the 12.7 MeV state in C-12 of unnatural parity are discussed. The breakup of the latter has been debated since more than a decade. Mirror beta transitions in the A = 9 chain are compared and a large asymmetry factor is deduced for the transitions to high excitation energy in Be-9 (11.8 MeV) and B-9 (12.2 MeV) fed in the beta-decay of Li-9 and C-9 respectively. It is shown that the asymmetry is not due to experimental problems or differences in the mechanisms of breakup or in the spin of the states. As no asymmetry is found in the gs to gs transition it must be due to the particular structure of these excited states. The controversy on the breakup mechanism of the 12.7 MeV state is resolved.
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| 3. |
- Lumpkin, A. H., et al.
(författare)
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Evidence for microbunching "sidebands" in a saturated free-electron laser using coherent optical transition radiation
- 2002
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Ingår i: Physical Review Letters. - 1079-7114. ; 88:23, s. 4-4
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Tidskriftsartikel (refereegranskat)abstract
- We report the first measurements of z -dependent coherent optical transition radiation (COTR) due to electron-beam microbunching at high gains (>10(4) ) including saturation of a self-amplified spontaneous emission free-electron laser (FEL). In these experiments the fundamental wavelength was near 530 nm, and the COTR spectra exhibit the transition from simple spectra to complex spectra (5% spectral width) after saturation. The COTR intensity growth and angular distribution data are reported as well as the evidence for transverse spectral dependencies and an "effective" core of the beam being involved in microbunching.
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| 4. |
- Zhang, Shi-Li, et al.
(författare)
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Abnormal anti-Stokes Raman scattering of carbon nanotubes
- 2002
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 66:3
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Tidskriftsartikel (refereegranskat)abstract
- Abnormal anti-Stokes Raman scattering (AASR) was unambiguously observed in carbon nanotubes (CNT's). In contrast to traditional Raman scattering theory, the absolute value of the Raman frequency of the anti-Stokes peak is not the same as that of the corresponding Stokes peak. It was demonstrated that AASR scattering originates from the unique nanoscale cylindrical structure of CNT's that can be considered naturally as a graphite structure with an intrinsic defect from its rolling. The double-resonance Raman scattering theory was applied to interpret the scattering mechanism of the AASR phenomenon successfully and quantitatively.
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| 7. |
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| 8. |
- Wang, X., et al.
(författare)
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Involvement of the MKK6-p38? cascade in ?-radiation-induced cell cycle arrest
- 2000
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Ingår i: Molecular and Cellular Biology. - 0270-7306 .- 1098-5549. ; 20:13, s. 4543-4552
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Tidskriftsartikel (refereegranskat)abstract
- The p38 group of kinases belongs to the mitogen-activated protein (MAP) kinase superfamily with structural and functional characteristics distinguishable from those of the ERK, JNK (SAPK), and BMK (ERK5) kinases. Although there is a high degree of similarity among members of the p38 group in terms of structure and activation, each member appears to have a unique function. Here we show that activation of p38-? (also known as ERK6 or SAPK3), but not the other p38 isoforms, is required for ?-irradiation- induced G2 arrest. Activation of the MKK6-p38? cascade is sufficient to induce G2 arrest in cells, and expression of dominant negative alleles of MKK6 or p38? allows cells to escape the DNA damage-induce G2 delay. Activation of p38? is dependent on ATM and leads to activation of Cds1 (also known as Chk2). These data suggest a model in which activation of ATM by ? irradiation leads to the activation of MKK6, p38?, and Cds1 and that activation of both MKK6 and p38? is essential for the proper regulation of the G2 checkpoint in mammalian cells.
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| 9. |
- Zhou, J., et al.
(författare)
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Self-excited piezoelectric microcantilever for gas detection
- 2003
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Ingår i: Microelectronic Engineering. - 0167-9317 .- 1873-5568. ; 69:1, s. 37-46
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Tidskriftsartikel (refereegranskat)abstract
- Design, fabrication and results from theoretical and experimental studies on the self-excited piezoelectric microcantilever are presented in this paper. Theoretical studies have been carried out to design the microcantilever and have been extended to harmonic analysis using the finite element technique. Silicon microfabrication has been successfully completed to create microcantilever devices. Experimental studies have been performed to obtain the resonance frequencies. Applied as a mass-sensitive sensor, the microcantilever has a sensitivity of - 0.0024%/ppm and a minimum mass loading of 3.5 x 10(-9) g with the help of a zeolite sensitive layer to freon.
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