| 1. |
- Besharat, Zahra
(författare)
-
Adsorption of molecular thin films on metal and metal oxide surfaces
- 2016
-
Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- Metal and metal oxides are widely used in industry, and to optimize their performance their surfaces are commonly functionalized by the formation of thin films. Self-assembled monolayers (SAMs) are deposited on metals or metal oxides either from solution or by gas deposition. Thiols with polar terminal groups are utilized for creating the responsive surfaces which can interact electrostatically with other adsorbates. Surface charge effects wetting and adhesion, and many other surface properties. Polar terminal groups in thiols could be used to modify these factors. Mixed SAMs can provide more flexible surfaces, and could change the resulting surface properties under the influence of factors such as pH, temperature, and photo-illumination. Therefore, in order to control these phenomena by mixed polar-terminated thiols, it is necessary to understand the composition and conformation of the mixed SAMs and their response to these factors. In this work, mixtures of thiols with carboxylic and amino terminal groups were studied. Carboxylic and amino terminal groups of thiol interact with each other via hydrogen bonding in solution and form a complex. Complexes adsorb to the surface in non-conventional orientations. Unmixed SAMs from each type, either carboxylic terminated thiols or amino terminated thiols are in standing up orientation while SAMs from complexes are in an axially in-plane orientation. Selenol is an alternative to replace thiols for particular applications such as contact with biological matter which has a better compatibility with selenol than sulfur. However, the Se-C bond is weaker than the S-C bond which limits the application of selenol. Understanding the selenol adsorption mechanism on gold surfaces could shed some light on Se-C cleavage and so is investigated in this work. Se-C cleavage happens in the low coverage areas on the step since atoms at steps have lower coordination making them more reactive than atoms on the terraces. Another area where the self-assembly of molecules is of importance is for dye sensitized solar cells, which are based on the adsorption of the dye onto metal oxides surfaces such as TiO2.The interface between the SAM of dye and the substrate is an important factor to consider when designing dyes and surfaces in dye sensitized solar cells (DSSCs). The quality of the self-assembled monolayers of the dye on the TiO2 surface has a critical influence on the efficiency of the DSSCs. Creation of just a monolayer of dye on the surface could lead to an efficient current of photo-excited electrons to the TiO2 and degeneration of the dye by redox. This work, T-PAC dye showed island growth with some ad-layer that is not in contact with the surface, whereas the MP13 dye adsorption is laminar growth. Cuprite (Cu2O) is the initial and most common corrosion product for copper under atmospheric conditions. Copper could be a good replacement for noble metal as catalysts for methanol dehydrogenation. Knowledge about the structure of Cu2O(100) and Cu2O(111) surfaces could be used to obtain a deeper understanding of methanol dehydrogenation mechanisms with respect to adsorption sites on the surfaces. In this work, a detailed study was done of Cu2O(100) surface which revealed the possible surface structures as the result of different preparation conditions. Studies of the structure of Cu2O(100) and Cu2O(111) surfaces show that Cu2O(100) has a comparatively stable surface and reduces surface reactivity. As a consequence, dehydrogenation of methanol is more efficient on the Cu2O(111) surface. The hydrogen produced from methanol dehydrogenation is stored in oxygen adatom sites on both surfaces.
|
|
| 2. |
|
|
| 3. |
- Arnadottir, Anna, et al.
(författare)
-
Universums mörka hemlighet
- 2018
-
Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- Here we follow the exciting exploration of dark matter, from the Big Bang to its anticipated discovery at the Large Hadron Collider. The first hints of dark matter were wound by Fritz Zwicky, the scientist who coined the term. We get to see the astral choreography witnessed by Vera Rubin in the Andromeda galaxy and then plummet deep underground to see the most sensitive dark matter detector on Earth, housed in a former gold mine.From there, we journey across space and time to the Large Hadron Collider at CERN, speeding alongside particles before they collide in visually stunning explosions of light and sound, while learning how scientists around the world are collaborating to track down the constituents of dark matter.
|
|
| 4. |
-
Exhibition: Space Waves and a Tale : Hannes Alfvén (1908–1995). Nobel Prize laureate in physics 1970.
- 2022
-
Konstnärligt arbeteabstract
- The exhibition Space Waves and a Tale presented parts of Alfvén's extensive research, his community engagement and last but not least, his fictional story The tale of the great computing machine from 1966. In 1970 KTH professor Hannes Alfvén (1908 – 1995) was awarded the Nobel Prize in physics for his discoveries and applications in plasma physics. The exhibition Space Waves and a Tale presented parts of Alfvén's extensive research, his community engagement and his fictional story The tale of the great computing machine from 1966.Alfvén's research allow us to explore all corners of the universe – from the auroras on earth to the auroras on other planets, from solar wind to stellar wind, from plasma phenomena in the laboratory to astrophysical plasma phenomena in ours and other galaxies.The tale of the great computing machine is a satirical tale that tells the story of a future society controlled by computers and is also the source of inspiration for an opera with the same name.As part of the exhibition Space Waves and a Tale visitors were invited to share their visions of how future technology will shape our lives and societies. Two students from the KTH School of Architecture have contributed to the exhibition by designing and building a flexible and sustainable exhibition module. Students from BOOMERANG REXUS participated with objects related to aerospace research.Space Waves and a Tale was produced by the project group for KTH 200 years anniversary celebration together with KTH Library, The Opera: The Tale of the Great Computing Machine, the Division of Space and Plasma Physics and the KTH School of Architecture.In connection with the exhibithion there was a book discussion, popular science lecture and a class visit.
|
|
| 5. |
- Panda, Pritam Kumar, PhD Student, 1991-
(författare)
-
GENOME2QUNOME : Interfacing Molecules with Nanomaterials
- 2023
-
Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- The advent of technological furtherance in the biomedical sector and the renaissance of interdisciplinary science enable us to comprehend human lifestyle, and diseases at molecular and nanoscale levels. Lacking a shared theoretical foundation and terminological lexicon between various scientific domains might impede efforts to incorporate biological principles into nanoscience. In retrospect, it's possible to draw some instructive learnings from the fact that the development of contemporary nanoscience and biology was the consequence of the convergence of fields that had previously been kept separate. In this Ph.D. thesis, I have given the catchy moniker “GENOME2QUNOME” (an acronym for "Genetic organization of multicellular organisms and their enzymatic reaction 2 Quantum nanostructured materials for energy scavenging applications"), encompassing a combinatorial approach using computational methodologies in biophysics and nano/materials science. Structure-property correlations, a unifying paradigm based on understanding how nanomaterials behave and what qualities they exhibit at the molecular and nanoscale levels, are now widely acknowledged and are critical in the incorporation of bioinspired materials into nanoscience. Therefore, a unified framework have been elucidated in this thesis for the study of nanoscale materials ranging from 0D to 3D that may be useful in combining various strategies that characterize this interdisciplinary approach. This thesis is also a part of broader interdisciplinary research strategy aimed at depicting electronic transport in the nanoscale regime, elucidating interface mechanisms for contact electrification, and understanding the complex architectures of nanomaterials. The central hypothesis of this thesis is concentrated on the behavioral transition from the nanoscale regime to macromolecules, which is fascinating in real world scenario but theoretically challenging to bring it in reality or practice. To bridge this gap, I have made an attempt by integrating a wide range of computational methods, ranging from density functional theory (DFT) for systems with few atoms to classical dynamics dealing with billions of atoms.
|
|
| 6. |
- Coetzee, Riaan Stuart, 1987-, et al.
(författare)
-
Gamma irradiation-induced absorption in single-domain and periodically-poled KTiOPO4 and Rb:KTiOPO4
- 2017
-
Ingår i: Optical Materials Express. - 2159-3930. ; 7:11, s. 4138-4146
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the effect of gamma radiation on flux grown KTiOPO4 and Rb:KTiOPO4 samples, as well as their periodically poled variants. Specifically, we study the altered transmission due to color-center formation via gamma irradiation. We measured the transmission of our samples for varying radiation doses and demonstrate effective temperature annealing of gamma radiation induced color centers. We measured a maximum transmission difference of 2% in our samples, which was easily corrected with temperature annealing. No long term and permanent changes were found to be induced in our samples.
|
|
| 7. |
- Arnadottir, Anna, et al.
(författare)
-
Människor på Månen : Månar och mindre himlakroppar
- 2019
-
Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- As we look up at night we see that our Earth has one moon orbiting it, the one we call the Moon. We have explored our moon with orbiters, rovers and astronauts, mapping it and studying its history.Other planets also have moons in orbit around them and these may look quite different from the Earth's moon. Some are small and look like asteroids, others are so icy they would become comets if they plunged on an elliptical orbit towards the inner solar system. This full dome planetarium production; "Man on the Moon" is a part of a series titled "Moons Beyond Counting". In this installment we look closer at NASA's Apollo missions and some more recent missions to the Moon.
|
|
| 8. |
- Kaewmaraya, Thanayut, 1984-
(författare)
-
First-Principles Studies of Materials Properties : Pressure-Induced Phase Transitions & Functional Materials
- 2015
-
Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents the first-principles studies of materials properties within the framework of the density functional theory (DFT). The thesis constitutes three main parts, i. e., pressure-induced phase transitions in solids, data-storage and clean-energy materials.The first part focuses on the predictions of crystal structures and the determinations of electronic properties of Xe-H2, FeB4 and Co3O4. Pressurizing Xe-H2 compound yields the formation of H-rich Xe(H2)8, which can exhibit a metallic feature at comparatively lower pressure than pure hydrogen. Hard superconducting FeB4 gets transformed into a novel transparent phase under pressure owing to the enhanced overlap of atomic cores. Spinel Co3O4 undergoes the phase transition from a cubic to a monoclinic because of the charge transfer between cations via the increased 3d-3d interactions.The second part involves the study of structural and electronic properties of phase-change memory materials (PCMs), i. e., Ge2Sb2Te5 (GST) and Ga-doped In2O3. Van der Waals (vdW) interaction must be considered to obtain accurate crystal structure of layered GST. For Ga-doped In2O3 (GIO), the local structure of amorphous GIO is found to resemble that of amorphous In2O3, except the vicinity of doping atoms. The electronic property of a-GIO is metallic, which considerably differs from the semiconducting feature of the crystalline GIO. This emphasizes the contrast in the conductivity of the crystalline and amorphous upon phase switching of GIO.The third part associates with the search for clean-energy materials, viz., hydrogen production, hydrogen storage and green Mg-ion batteries. For hydrogen production, the role of intrinsic point defects to water adsorption on ZnO(10-10) surface is investigated. The findings show that the Zn and O defect-sites are energetically not favorable for the water adsorption and dissociation. For the purpose of storing hydrogen in a solid phase, silicene, doped by alkaline and alkaline earth metals, is investigated. We find that Li-doped and Na-doped silicene can attain the superior storage capacity. For cathode material of Mg-ion batteries, Mg2Mo6S8, the diffusivity of Mg ions occurs through an available channel in the bulk with the onset temperature of 200 K.
|
|
| 9. |
- Kudryavtsev, Daniil, et al.
(författare)
-
Raman high-pressure study of butane isomers up to 40 GPa
- 2018
-
Ingår i: AIP Advances. - : American Institute of Physics (AIP). - 2158-3226. ; 8:11
-
Tidskriftsartikel (refereegranskat)abstract
- Raman spectroscopy studies on n and i-butane were performed at pressures of up to 40 GPa at ambient temperatures using the DAC technique. Normal butane undergoes two phase transitions at 1.9(5) GPa and 2.9(5) GPa and isobutane at 2.7(5) GPa and 3.5(5) GPa. These phase transitions were identified based on observations of the splitting Raman modes and the appearance or disappearance of particular Raman peaks. Our results demonstrate the complex, high-pressure behavior of butane isomers.
|
|
| 10. |
|
|
