| 1. |
- Abazov, V. M., et al.
(författare)
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The upgraded DO detector
- 2006
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 565:2, s. 463-537
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Tidskriftsartikel (refereegranskat)abstract
- The DO experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid -argon calorimeters and central muon detector, remaining from Run 1, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to DO.
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| 2. |
- Shur, Vladimir, et al.
(författare)
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Nanoscale Domain Effects in Ferroelectrics. Formation and Evolution of Self-Assembled Structures in LiNbO3and LiTaO3
- 2007
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Ingår i: Ferroelectrics (Print). - : Informa UK Limited. - 0015-0193 .- 1563-5112. ; 354, s. 145-157
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Tidskriftsartikel (refereegranskat)abstract
- We discuss the most interesting nanoscale domain effects resulting in formation andevolution of self-assembled domain structures in various representatives of LiNbO3 andLiTaO3 family. Several exotic domain kinetic scenarios for complete suppression of theclassical wall motion have been revealed. It has been shown that the modification of thesurface layer allows to obtain: (1) the wall motion controlled by merging with nanoscaledomains generated in front of the moving wall and (2) the discrete switching by enlarge-ment of the web-like self-assembled ensemble of isolated domains. The formation ofnanoscale quasi-periodic and self-similar structures during cooling after pulse heatingwithout any application of external electric field was studied. It has been shown thatall experimental results can be explained, if the retardation of the bulk screening of thedepolarization field is taken into account.
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| 3. |
- Shur, Vladimir, et al.
(författare)
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Self-Organization in LiNbO3 and LiTaO3 : formation of Micro- and Nano-Scale Domain Patterns
- 2004
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Ingår i: Ferroelectrics (Print). - : Informa UK Limited. - 0015-0193 .- 1563-5112. ; 304, s. 111-116
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Tidskriftsartikel (refereegranskat)abstract
- We review the study of self-organized formation of several types of quasi-regular micro- and nano-scale domain patterns in single crystalline LiNbO3 and LiTaO3 samples with artificial surface dielectric layers. The domain images revealed by chemical etching have been visualized using optical, scanning electron and scanning probe microscopy (SPM) in contact atomic force mode. SPM piezoresponse imaging mode allows us to investigate the domain structure under the sample surface. We classify the obtained quasi-regular domain structures and discuss the mechanism of their formation and self-maintained growth.
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| 4. |
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| 5. |
- Gladnishki, KA, et al.
(författare)
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Angular Momentum Population in the Projectile Fragmentation of 238U at 750 MeV/nucleon
- 2004
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 69:2
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Tidskriftsartikel (refereegranskat)abstract
- A systematic study of the population probabilities of nanosecond and microsecond isomers produced following the projectile fragmentation of U-238 at 750 MeV/nucleon has been undertaken at the SIS/FRS facility at GSI. Approximately 15 isomeric states in neutron-deficient nuclei around A similar to 190 were identified and the corresponding. isomeric ratios determined. The results are compared with a model based on the statistical abrasion-ablation description of relativistic fragmentation and simple assumptions concerning gamma cascades in the final nucleus (sharp cutoff). This model represents an upper limit for the population of isomeric states in relativistic projectile fragmentation. When the decay properties of the states above the isomer are taken into account, as opposed to the sharp cutoff approximation, a good agreement between the experimental and calculated angular momentum population is obtained.
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| 6. |
- Gladnishki, KA, et al.
(författare)
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Isomer spectroscopy in the neutron-deficient lead region following projectile fragmentation
- 2003
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Ingår i: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 34:4, s. 2395-2398
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Tidskriftsartikel (refereegranskat)abstract
- Projectile fragmentation of a 750 MeV/nucleon U-238 beam was used to populate neutron-deficient nuclei around A similar to190. Isomeric states in Hg, Tl, Pb, Bi, and Po isotopes were identified and their lifetimes determined, with the ultimate aim of measuring their isomeric ratios to provide information on the spin population in such reactions.
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| 7. |
- Lobov, A., et al.
(författare)
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Field induced evolution of regular and random 2D domain structures and shape of isolated domains in LiNbO3 and LiTaO3
- 2006
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Ingår i: Ferroelectrics (Print). - : Informa UK Limited. - 0015-0193 .- 1563-5112. ; 341:1, s. 109-116
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Tidskriftsartikel (refereegranskat)abstract
- The shapes of isolated domains produced by application of the uniform external electric field in different experimental conditions were investigated experimentally in single crystalline lithium niobate LiNbO3 and lithium tantalate LiTaO3. The study of the domain kinetics by computer simulation and experimentally by polarization reversal of the model structure using two-dimensional regular electrode pattern confirms applicability of the kinetic approach to explanation of the experimentally observed evolution of the domain shape and geometry of the domain structure. It has been shown that the fast domain walls strictly oriented along X directions appear after domain merging.
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| 8. |
- Matveev, V. V., et al.
(författare)
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Investigation of Melts of Polybutylcarbosilane Dendrimers by 1H NMR Spectroscopy
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Melts of polybutylcarbosilane (PBC) dendrimers from third (G3) up to sixth (G6) generations are investigated by 1H NMR spectroscopy in a wide temperature range up to 493 K. At room temperature, NMR spectra of G3-G5 dendrimers exhibit resolved, solution-like spectra ("liquid" phase). In contrast, the spectrum of the G6 dendrimer is characterized by a single unresolved broad line at whole temperature range, which supports the presence of an anomalous phase state of G6 at temperatures higher than glass transition temperature. For the first time, an unexpected transition of G5 dendrimer from a molecular liquid state to an anomalous state/phase upon temperature increase has been detected using NMR data. Specifically, an additional wide background line appears in the G5 spectrum above 473 K, and this line corresponds to a G5 state characterized by restricted molecular mobility, i.e., a state similar to the "anomalous" phase of G6 melt. The fraction of the G5 dendrimers in "anomalous" phase at 493 K is approximately 40%. Analysis of the spectral shapes suggests that changes in the G5 dendrimers are reversible with temperature.
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| 9. |
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| 10. |
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| 11. |
- Shur, Vladimir, et al.
(författare)
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Modification of the Domain Kinetics in Congruent Lithium Niobate by Proton Exchanged Surface Layers
- 2006
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Konferensbidrag (refereegranskat)abstract
- We have studied the domain kinetics in congruent lithium niobate (CLN) single crystals with different types of the proton exchanged surface layers. The influence of the artificial dielectric layers and the surface gradient of the spontaneous polarization on the domain structure geometry, the shape of the individual domains, and the switching parameters were demonstrated. It was shown that after several cycles of polarization reversal the domain kinetics changes drastically. As a result the domain geometry is defined by spatial distribution of the residual domains existing in the area of domain merging during the previous switching. The role of residual domains increases with the cycle number.
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| 12. |
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