| 1. |
- Friedlein, Rainer, et al.
(författare)
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Electronic structure of highly ordered films of self-assembled graphitic nanocolumns
- 2003
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 68:19, s. 195414-
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Tidskriftsartikel (refereegranskat)abstract
- Highly ordered, several nanometers thick films of alkylated large planar, polycyclic aromatic hydrocarbon (PAH) molecules have been grown on semi-metallic molybdenum disulfide substrates. The films are characterized by a two-dimensional lateral arrangement of columns standing at the surface on a macroscopic scale. The self-assembly of such insulated columns of face-to-face disks with surface-induced vertical alignment has been achieved directly from solution processing. Angle-resolved photoelectron spectra revealed a highly anisotropic quasi-one-dimensional electronic structure with an extended π-electronic wave function. An intermolecular dispersion of the highest occupied band of at least 0.15 eV along the stacking direction has been measured. A partial breakdown of the concept of quasimomentum due to the finite size of the nano-objects perpendicular to the stacks is observed.
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| 2. |
- Osikowicz, Wojciech, et al.
(författare)
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A joint theoretical and experimental study on the electronic properties of phenyl-capped 3,4-ethylenedioxythiophene oligomers
- 2003
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 119:19, s. 10415-10420
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of a series of phenyl-capped EDOT oligomers was studied using ultraviolet photoelectron spectroscopy, in combination with quantum-chemical methods. The bulk IP of the neutral PEDOT polymer was estimated to be 4.2 eV. The frontier band structue was predicted from the evolution of the spectral features in the studied series of oligomers.
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| 3. |
- Ayres-de-Campos, D, et al.
(författare)
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Can the reproducibility of fetal heart rate baseline estimation be improved?
- 2004
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Ingår i: European Journal of Obstetrics, Gynecology, and Reproductive Biology. - 0301-2115. ; 112:1, s. 49-54
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate the reproducibility of fetal heart rate (FHR) baseline estimation according to an objective and detailed definition presented in this article, by comparison with the FIGO guidelines' definition. Study design: Three hundred consecutively acquired FHR tracings, 150 from antepartum high-risk pregnancies and 150 from unselected intrapartum cases, were presented to nine experienced clinicians included in three different groups, for an estimation of the FHR baseline. The first group consisted of clinicians using the proposed definition, without previous training in its use. The second group consisted of clinicians using the proposed definition, where a previous training session was promoted. The third group consisted of clinicians using the FIGO guidelines' definition. Agreement in baseline estimation was evaluated using the kappa statistic, the proportions of agreement and the intra-class correlation coefficient. Results: Using the baseline definition proposed in this article, agreement was significantly higher in the group with prior training in its use. This group also showed a trend towards a higher agreement than the one using the FIGO guidelines. Conclusion: The FHR baseline definition proposed in this article provides an extremely reproducible estimation when associated with prior training in its use.
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| 4. |
- Crispin, Annica, et al.
(författare)
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Influence of dopant on the electronic structure of spiro-oligophenyl-based disordered organic semiconductors
- 2002
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 116:18, s. 8159-8167
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Tidskriftsartikel (refereegranskat)abstract
- The influence of the dopant on the electronic structure of spiro-oligophenyl-based disordered organic semiconductors was studied by means of photoelectron spectroscopy. With lithium atoms as dopants, two charges were stored on the same spiro branch in the form of bipolarons, for spiro-quarterphenyl and spiro-sexiphenyl. For doping with the sodium atoms, the size of the counter ions made it less energetically desirable to store two charges onto a single branch, and the charged species were polarons independent of the level of doping which was confirmed by optical absorption data.
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| 5. |
- de Jong, Michel P, et al.
(författare)
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The electronic structure of n- and p-doped phenyl-capped 3,4-ethylenedioxythiophene trimer
- 2003
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 118:14, s. 6495-6502
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Tidskriftsartikel (refereegranskat)abstract
- A study was conducted on the effects of chemical doping on the chemical and electronic structure of condensed molecular solid films of the ethylenedioxythiophene (EDOT) trimer using ultraviolet photoelectron spectroscopy (UPS) and x-ray photoelectron spectroscopy (XPS). Phenyl-capped EDOT oligomers were potential candidates for molecular electronics applications and serve as model molecules for PEDOT. By combining UPS, XPS, and NEXAFS, a clear picture of the doping induced changes in the electronic structure of phenyl-capped EDOT-trimer was obtained.
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| 6. |
- Llopart Cudié, Xavier, et al.
(författare)
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Medipix2, a 64k pixel readout chip with 55 μm square elements working in single photon counting mode
- 2002
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 49, s. 2279-2283
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Tidskriftsartikel (refereegranskat)abstract
- The Medipix2 chip is a pixel detector readout chip consisting of 256×256 identical elements, each working in single photon counting mode for positive or negative input charge signals. Each pixel cell contains around 500 transistors and occupies a total surface area of 55 μm×55 μm. A 20 μm width octagonal opening connects the detector and the preamplifier input via bump-bonding. The preamplifier feedback provides compensation for detector leakage current on a pixel by pixel basis. Two identical pulse height discriminators are used to create a pulse if the preamplifier output falls within a defined energy window. These digital pulses are then counted with a 13-bit pseudo-random counter. The counter logic, based in a shift register, also behaves as the input/output register for the pixel. Each cell also has an 8-bit configuration register which allows masking, test-enabling and 3-bit individual threshold adjust for each discriminator. The chip can be configured in serial mode and read out either serially or in parallel. The chip is designed and manufactured in a 6-metal 0.25 μm CMOS technology. Preliminary measurements show very good agreement with simulations.
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| 7. |
- Thibert-Plante, Xavier, 1980-, et al.
(författare)
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A simple spectral algorithm for solving large-scale Poisson equation in 2D
- 2003
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Ingår i: Computer Physics Communications. - : Elsevier. - 0010-4655 .- 1879-2944. ; 154:2, s. 89-97
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Tidskriftsartikel (refereegranskat)abstract
- We show that it is possible with easy-to-program algorithms to reach spatial resolutions of the order of 108 grid points for computing the electric potential on 2D periodic lattices, such as the Si(111)7×7 surface. We have used a spectral Fourier technique and parallelized FFTs with OPEN_MP on SGI machines. This method can be easily extended to 3D.
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