| 1. |
- Anttu, Nicklas, et al.
(författare)
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Light scattering and plasmon resonances in a metal film with sub-wavelength nano-holes
- 2008
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6596 .- 1742-6588. ; 100, s. 052037-052037
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Konferensbidrag (refereegranskat)abstract
- We report on a theoretical study of optical extinction in a metal film of 15-230 nm in thickness patterned periodically with sub-wavelength nano-holes of 140 nm in diameter. The gold plate was on a thick SiO2 wafer and the nano-holes as well as the top side of the metal plate were filled with water or solvent. Light was sent in toward the plate from the SiO2 side. The simulations were performed by solving the Maxwell equations using the scattering matrix method. It was seen that the extinction can, depending on the periodicity of the hole array, show one or several peaks in the visible wavelength range. The positions of the peaks were redshifted when the thickness of the gold plate was decreased. It was found that the peak positions for a thick plate can be identified from a simple surface plasmon dispersion relation.
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| 2. |
- Constantinian, K. Y., et al.
(författare)
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Electron transport and microwave dynamics of hybrid Nb/Au/CaSrCuO/YBaCuO planar Josephson junctions
- 2009
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 234:4, s. Art. no. 042004-
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Konferensbidrag (refereegranskat)abstract
- We report on measurements of dc electron transport and microwave dynamics of thin film hybrid Josephson junctions with an oxide antiferromagnetic interlayer. The base superconducting electrode YBaCuO and the antiferromagnetic (AF) interlayer CaSrCuO (with thickness d 20 - 70 nm) were grown by laser ablation on NdGaO3 substrates. I-V curves were well fitted to RSJ model and had no excess current, ICRN products were of order 0.2 mV at T=4.2 K. We did not observe any noticeable reduction of I CRN with increasing d. Such "tunnellike" behaviour also resulted in appearance of singularities on I-V curve when magnetic field was applied. Oscillating with microwave power integer and half-integer Shapiro steps were registered along with sub-harmonic detector response. Moreover, for some of junctions a "devil" staircase structure was observed on I-V curves and giant noise-like signals were measured in 1-2 GHz band at the certain levels of microwave power. Observed features, noise performance and the impact of the second harmonic in current-phase relation on junction dynamics are discussed taking into account data for structures without AF interlayer.
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| 3. |
- Flechl, Martin, et al.
(författare)
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Grid interoperability : joining grid information systems
- 2007
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 119:6, s. 062030-
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Tidskriftsartikel (refereegranskat)abstract
- A grid is defined as being 'coordinated resource sharing and problem solving in dynamic, multi-institutional virtual organizations'. Over recent years a number of grid projects, many of which have a strong regional presence, have emerged to help coordinate institutions and enable grids. Today, we face a situation where a number of grid projects exist, most of which are using slightly different middleware. Grid interoperation is trying to bridge these differences and enable Virtual Organizations to access resources at the institutions independent of their grid project affiliation. Grid interoperation is usually a bilateral activity between two grid infrastructures. Recently within the Open Grid Forum, the Grid Interoperability Now (GIN) Community Group is trying to build upon these bilateral activities. The GIN group is a focal point where all the infrastructures can come together to share ideas and experiences on grid interoperation. It is hoped that each bilateral activity will bring us one step closer to the overall goal of a uniform grid landscape. A fundamental aspect of a grid is the information system, which is used to find available grid services. As different grids use different information systems, interoperation between these systems is crucial for grid interoperability. This paper describes the work carried out to overcome these differences between a number of grid projects and the experiences gained. It focuses on the different techniques used and highlights the important areas for future standardization.
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| 4. |
- Fynbo, H. O. U., et al.
(författare)
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The β-decay approach for studying 12C
- 2008
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 111:1
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Tidskriftsartikel (refereegranskat)abstract
- The β-decays of the mirror nuclei 12B and 12N both populate states in 12C and they are therefore a precious source of information about this nucleus. Due to the selection rules of β-decay only 0+, 1+ and 2+ states are populated. This allows a very clean study of unbound states just above the 3α-threshold with those spin and parities. This probe has been applied in two experiments using two complementary experimental techniques: in the first the three α-particles emitted after β-decay are measured in coincidence in separate detectors using the ISOL method, while in the second method 12B and 12N are implanted in a detector and the summed energy of the three α-particles is measured directly. Preliminary results from the two approaches are presented. © 2008 IOP Publishing Ltd.
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| 5. |
- Halvarsson, Mats, 1965, et al.
(författare)
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Thin foil analysis in the SEM
- 2008
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 126, s. 4-
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Tidskriftsartikel (refereegranskat)abstract
- This paper explores the possibilities for imaging and chemical analysis of thin foil specimens in the SEM. Bright field and dark field imaging provide high resolution imaging with crystallographic information within the grains. In multiphase materials with varying electron transmission the dark field images generally provide a more even contrast in all phases. It is possible to obtain high-quality quantitative EDX data with high spatial resolution.
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| 6. |
- Kawabata, Shiro, et al.
(författare)
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Theory of two-dimensional macroscopic quantum tunneling in a Josephson junction coupled with an LC circuit
- 2009
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 150:5, s. 052105-
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Konferensbidrag (refereegranskat)abstract
- We investigate classical thermal activation (TA) and macroscopic quantum tunneling (MQT) for a Josephson junction coupled with an LC circuit theoretically. The TA and MQT escape rate are calculated analytically by taking into account the two-dimensional nature of the classical and quantum phase dynamics. We find that the MQT escape rate is largely suppressed by the coupling to the LC circuit. On the other hand, this coupling gives rise to slight reduction of the TA escape rate. These results are relevant for the interpretation of a recent experiment on the MQT and TA phenomena in grain boundary YBCO Josephson junctions.
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| 7. |
- Lenz, Annika, et al.
(författare)
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Quantum-chemical investigations of phenol and larger aromatic molecules at the TiO2 anatase (101) surface
- 2008
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 117, s. 012020-(8 pp)
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Tidskriftsartikel (refereegranskat)abstract
- Adsorption of aromatic molecules at the (101) surface of titanium dioxide anatase is studied by quantum-chemical B3LYP computations, where both cluster and periodic calculations were performed and compared. For phenol different adsorption modes at a TiO2 cluster were mapped out and the energetically most favourable conformation was used for investigation of the electronic structure, for periodic calculations, and as a mould for the adsorption modes of phenylmethanol, phenylethanol, naphthalen-2-ol, phenanthren-2-ol, pyren-2-ol and perylen-2-ol. The alcohols form a H-bond to a surface O and a O(molecule)-Ti bond. For the larger aromatic molecules their increasingly higher HOMO levels decrease the effective bad gap of the system. Inclusion of spacer groups as in phenylmethanol and phenylethanol results in higher adsorption energies and larger band gaps. The LUMOs for the adsorbates help visualize the electronic coupling to the surface. Comparison of the cluster with the periodic model indicates that the former describes the electronic coupling in a similar manner as the latter, although the former lacks in the description of the anatase substrate.
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| 8. |
- Madurga, M., et al.
(författare)
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Study of β-delayed charged particle emission of 11Li: Evidence of new decay channels
- 2008
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 111:1
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Tidskriftsartikel (refereegranskat)abstract
- The break-up of the 18.2 MeV state in 11Be was studied in a 11Li β-decay experiment. We report here on the study of the dominating breakup channels involving na6He or 3n2α in the final state, with special emphasis dedicated in this contribution to the three-particle channel. The two emitted charged particles were detected in coincidence using a highly segmented experimental set-up. The observed experimental energy-vs-energy scatter plot indicates a sequential breakup where nuclei of mass 4, alpha particles, and mass 7, 7He, are involved. A Monte-Carlo simulation of the sequential channel, 11Be* → α + 7He → nα6He was performed and compared to the experimental data and to a simulation of the direct break-up of the 18.2 MeV state nα6He by phase space energy distribution. The energy-versus-energy plot are explained by the sequential simulation but not by the phase space simulation.
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| 9. |
- Skjolding, Lars Henrik, et al.
(författare)
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Characterisation of nano-interdigitated electrodes
- 2008
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6596 .- 1742-6588. ; 100, s. 052045-052045
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Konferensbidrag (refereegranskat)abstract
- Interdigitated electrodes made up of two individually addressable interdigitated comb-like electrode structures have frequently been suggested as ultra sensitive electrochemical biosensors. Since the signal enhancement effects due to cycling of the reduced and oxidized species are strongly dependent on the inter electrode distances, since the nature of the enhancement is due to overlying diffusion layers, inter digitated electrodes with an electrode separation of less the non emicrometer a redesired for maximum signal amplification. Fabrication of submicron structures can only be made by advanced lithography techniques. By use of electron be amlithography we have fabricated arrays of interdigitated electrodes with an electrode separation distance of 200nm and an electrode finger width of likewise 200nm. The entire electrode structure is 100 micrometre times 100 micrometre, and the active electrode area is dictated by the opening in the passivation layer, that is defined by UV lithography. Here we report measurements of redox cycling of ferrocyanide by coupled cyclic voltammograms, where the potential atone of the working electrodes are varied and either an oxidising or reducing potential is applied to the complimentary interdigitated electrode. The measurements show fast conversion and high collection efficiency round 87% as expected for nano-interdigitated electrodes.
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| 10. |
- Larson, Åsa, et al.
(författare)
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Ion-pair formation in electron recombination with molecular ions
- 2007
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 88, s. 012065-1-012065-8, s. 012065-
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Tidskriftsartikel (refereegranskat)abstract
- By studying ion-pair formation in electron recombination with molecular ions,fundamental knowledge on the molecular dynamics can be obtained. In order to study thesetypes of reactions, both the electron recombination as well as the dynamics all the way to theasymptotic limits must be well described. We have used the wave packet technique to studyion-pair formation in electron recombination with HeH+, HD+, H3+ and HF+. We here discusswhat will determine the general shape of the ion-pair cross section, the threshold effects, possibleinterference effects as well as the ratio of the cross sections of ion-pair formation to dissociativerecombination.
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