| 1. |
- Nilson, Katharina, et al.
(författare)
-
Rubidium Doped Metal-Free Phthalocyanine Monolayer Structures on Au(111)
- 2010
-
Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:28, s. 12166-12172
-
Tidskriftsartikel (refereegranskat)abstract
- Scanning tunneling microscopy (STM) studies of monolayer of metal-free phthalocyanine (H2Pc) adsorbed on Au(111) have shown ordered arrangement of the molecules on the surface. Evaporation of H2Pc onto the Au(111) surface and post annealing of the sample to 670 K results in a densely packed structure of the molecules. The monolayer is characterized by molecules adsorbed with the molecular plane parallel to the substrate surface in a square adsorption unit cell. Furthermore, the high resolution images revealed the orientation of individual molecules. The H2Pc/Au(111) system has also been doped by rubidum and compared to the undoped layers. The Rb affects the molecular adsorption geometry, and a hexagonal unit cell is found for the coadsorption of H2Pc and Rb. Upon doping, highly ordered Rb-induced protrusions are observed at the benzene site of adsorbed molecules.
|
|
| 2. |
- Dodig-Crnkovic, Gordana, 1955
(författare)
-
On the Foundations of Computing. Computing as the Fourth Great Domain of Science
- 2023
-
Ingår i: Global Philosophy. - 2948-152X .- 2948-1538. ; 33:16
-
Tidskriftsartikel (refereegranskat)abstract
- This review essay analyzes the book by Giuseppe Primiero, On the foundations of computing. Oxford: Oxford University Press (ISBN 978-0-19-883564-6/hbk; 978-0-19-883565-3/pbk). xix, 296 p. (2020). It gives a critical view from the perspective of physical computing as a foundation of computing and argues that the neglected pillar of material computation (Stepney) should be brought centerstage and computing recognized as the fourth great domain of science (Denning).
|
|
| 3. |
- Castleton, Christopher, 1969-, et al.
(författare)
-
Managing the supercell approximation for charged defects in semiconductors : Finite-size scaling, charge correction factors, the band-gap problem, and the ab initio dielectric constant
- 2006
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 73:035215, s. 11-
-
Tidskriftsartikel (refereegranskat)abstract
- The errors arising in ab initio density functional theory studies of semiconductor point defects using the supercell approximation are analyzed. It is demonstrated that (a) the leading finite size errors are inverse linear and inverse cubic in the supercell size and (b) finite size scaling over a series of supercells gives reliable isolated charged defect formation energies to around +-0.05 eV. The scaled results are used to test three correction methods. The Makov-Payne method is insufficient, but combined with the scaling parameters yields an ab initio dielectric constant of 11.6+-4.1 for InP. Gamma point corrections for defect level dispersion are completely incorrect, even for shallow levels, but realigning the total potential in real-space between defect and bulk cells actually corrects the electrostatic defect-defect interaction errors as well. Isolated defect energies to +-0.1 eV are then obtained using a 64 atom supercell, though this does not improve for larger cells. Finally, finite size scaling of known dopant levels shows how to treat the band gap problem: in < or = 200 atom supercells with no corrections, continuing to consider levels into the theoretical conductin band (extended gap) comes closest to experiment. However, for larger cells or when supercell approximation errors are removed, a scissors scheme stretching the theoretical band gap onto the experimental one is in fact correct.
|
|
| 4. |
- Gustafsson, Peter, et al.
(författare)
-
The problem-solving process in physics as observed when engineering students at university level work in groups
- 2015
-
Ingår i: European Journal of Engineering Education. - : Informa UK Limited. - 0304-3797 .- 1469-5898. ; 40:4, s. 380-399
-
Tidskriftsartikel (refereegranskat)abstract
- The problem-solving process is investigated for five groups of students when solving context-rich problems in an introductory physics course included in an engineering programme. Through transcripts of their conversation, the paths in the problem-solving process have been traced and related to a general problem-solving model. All groups exhibit backward moves to earlier stages in the problem-solving process. These earlier stages are revisited by the groups for identifying sub-problems, setting parameter values or even restating the goal. We interpret this action as coming from the fact that the students have not yet developed a knowledge base and a problem-solving scheme. Connected to the backward moves in the process are opportunities for the group members to build such a knowledge base from contributions and experiences from all group members. Problem contents that induce such moves are identified and can thus be considered by science teachers when constructing problems for group work.
|
|
| 5. |
- Lu, Zhansheng, et al.
(författare)
-
Cu-doped ceria : Oxygen vacancy formation made easy
- 2011
-
Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 510:1-3, s. 60-66
-
Tidskriftsartikel (refereegranskat)abstract
- DFT + U calculations of Cu-doped bulk ceria are presented. The first oxygen vacancy in Cu-doped ceria forms almost spontaneously and the second vacancy is also easily created. Whether zero, one or two oxygen vacancies, the Cu dopant is in the form Cu(+ II), and prefers to be 4-coordinated in a close to planar structure. Charge compensation, structural relaxation and available Cu-O states all play roles in lowering the O vacancy formation energies, but to different degrees when the first and second oxygen vacancies are formed. The Cu-doped ceria(1 1 1) surface system behaves in a similar fashion.
|
|
| 6. |
- Weyns, Danny, et al.
(författare)
-
A Research Agenda for Smarter Cyber-Physical Systems
- 2021
-
Ingår i: Journal of Integrated Design & Process Science. - Amsterdam, Netherlands : IOS Press BV. - 1092-0617 .- 1875-8959. ; 25:2, s. 27-47
-
Tidskriftsartikel (refereegranskat)abstract
- With the advancing digitisation of society and industry we observe a progressing blending of computational, physical, and social processes. The trustworthiness and sustainability of these systems will be vital for our society. However, engineering modern computing systems is complex as they have to: i) operate in uncertain and continuously changing environments, ii) deal with huge amounts of data, and iii) require seamless interaction with human operators. To that end, we argue that both systems and the way we engineer them must become smarter. With smarter we mean that systems and engineering processes adapt and evolve themselves through a perpetual process that continuously improves their capabilities and utility to deal with the uncertainties and amounts of data they face. We highlight key engineering areas: cyber-physical systems, self-adaptation, data-driven technologies, and visual analytics, and outline key challenges in each of them. From this, we propose a research agenda for the years to come.
|
|
| 7. |
- Tuvblad, Catherine, 1968-, et al.
(författare)
-
Physical and verbal aggressive behavior and COMT genotype : Sensitivity to the environment
- 2016
-
Ingår i: American Journal of Medical Genetics Part B. - Hoboken, USA : John Wiley & Sons. - 1552-4841 .- 1552-485X. ; 171:5, s. 708-718
-
Tidskriftsartikel (refereegranskat)abstract
- Catechol-O-methyltransferase (COMT) genotype has been implicated as a vulnerability factor for several psychiatric diseases as well as aggressive behavior, either directly, or in interaction with an adverse environment. The present study aimed at investigating the susceptibility properties of COMT genotype to adverse and favorable environment in relation to physical and verbal aggressive behavior. The COMT Val158Met polymorphism was genotyped in a Swedish population-based cohort including 1,783 individuals, ages 20-24 years (47% males). A significant three-way interaction was found, after correction for multiple testing, between COMT genotype, exposure to violence, and parent-child relationship in association with physical but not verbal aggressive behavior. Homozygous for the Val allele reported lower levels of physical aggressive behavior when they were exposed to violence and at the same time experienced a positive parent-child relationship compared to Met carriers. Thus, susceptibility properties of COMT genotype were observed in relation to physical aggressive behavior supporting the hypothesis that COMT genotypes are modifying the sensitivity to environment that confers either risk or protection for aggressive behavior. As these are novel findings, they warrant further investigation and replication in independent samples.
|
|
| 8. |
- Nilson, Katharina, et al.
(författare)
-
STM and XPS characterization of Zinc Phthalocyanine on InSb(001)
- 2008
-
Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 602:2, s. 452-459
-
Tidskriftsartikel (refereegranskat)abstract
- Zinc phthalocyanine (ZnPc) adsorbed on the InSb(0 0 1)-c(8 x 2) surface has been studied by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). Coverages from sub-monolayer to monolayer (ML) have been investigated. The molecules form ordered structures on the reconstructed rows of the surface with the molecular plane parallel to the surface. A change in the electronic structure between the sub-ML and higher coverages has been observed. Moreover, in order to study the influence of annealing on the electronic and geometric structures, the samples have been heated to elevated temperatures (about 640 K). In addition, multi-layer ZnPc films have been characterized by XPS measurements.
|
|
| 9. |
- Dirnfeld, Ruth, et al.
(författare)
-
Railway Digital Twins and Artificial Intelligence : Challenges and Design Guidelines
- 2022
-
Ingår i: Dependable Computing – EDCC 2022 Workshops. - Cham : Springer Science and Business Media Deutschland GmbH. - 9783031162442 - 9783031162459 ; , s. 102-113
-
Konferensbidrag (refereegranskat)abstract
- In the last years, there has been a growing interest in the emerging concept of Digital Twins (DTs) among software engineers and researchers. DTs represent a promising paradigm to enhance the predictability, safety, and reliability of cyber-physical systems. They can play a key role in different domains, as it is also witnessed by several ongoing standardisation activities. However, several challenging issues have to be faced in order to effectively adopt DTs, in particular when dealing with critical systems. This work provides a review of the scientific literature on DTs in the railway sector, with a special focus on their relationship with Artificial Intelligence. Challenges and opportunities for the usage of DTs in railways have been identified, with interoperability being the most discussed challenge. One difficulty is to transmit operational data in real-time from edge systems to the cloud in order to achieve timely decision making. We also provide some guidelines to support the design of DTs with a focus on machine learning for railway maintenance.
|
|
| 10. |
- Berner, Simon, et al.
(författare)
-
Activity boost of a biomimetic oxidation catalyst by immobilization onto a gold surface
- 2006
-
Ingår i: Journal of Catalysis. - : Elsevier BV. - 0021-9517 .- 1090-2694. ; 244:1, s. 86-91
-
Tidskriftsartikel (refereegranskat)abstract
- Thiol-functionalized cobalt porphyrins were used as a model system for investigating catalytic activity in homogeneous and heterogeneous oxidation catalysis. Self-assemble monolayers of thiol-functionalized cobalt porphyrins were prepared on a gold surface and served as heterogenous catalysts. These immoblilized molecules prevented the strong inactivation observed for their homogeneous congener. As a result, the turnover number per molecule in heterogeneous catalysis was at least 100 times higher than that of the corresponding homogeneous catalyst. It is atypical for a heterogenized catalyst to outperform its homogeneous congener. The properties of the molecular layers were characterized on the molecular level by means of X-ray photoelectorn spectroscopy (XPS) and scanning tunneling microscopy (STM). The results demonstrate that the performance of these biomimetic catalysts can be dramatically improved if the catalyst arangement can be controlled on the molecular level.
|
|
