1. Advantages and disadvantages of experiments with ultrashort two-color pulsesMatija Stupar, 2020, doktorska disertacija Opis: Advances in the development of lasers have led to a new class of radiation sources generating coherent, tunable, ultrashort light pulses in the spectral region ranging from infrared to soft X-rays. This includes high-order harmonics generation in gas (HHG), on which relies the CITIUS facility at University of Nova Gorica (Slovenia), and free-electron lasers (FELs), such as the facility FERMI at Elettra-Sincrotrone Trieste (Italy). The distinctive structure of HHG and FEL radiation paved the way to time-resolved experiments, which are performed to investigate events occurring on a short, or very short, temporal scale, from picoseconds to femtoseconds.
This work focuses on the advantages and disadvantages of some experimental techniques based on using these novel light sources to investigate the microscopic and/or ultrafast dynamics of matter samples, which have been previously driven out of equilibrium.
Advantages rely on the implementation of various applications based on two-color schemes and, more specifically, include the possibility of acquiring two-dimensional frequency maps, measuring electrons’ effective masses, or investigating electronic properties decoupled from the influence of the lattice. Particular focus will be put on experimental methods relying on photoelectric effect and photoelectron spectroscopy. In all experiments, we took advantage of one or more specific properties of HHG and FEL sources, such as controllable chirp, to study laser dressed states in helium, variable polarization, to study electronic properties of iron-based pnictides and ultrashort pulses (< 10 fs) to study the purely electronic dynamics in transition metal dichalcogenides.
On the other hand, the study of the interface between a molecule and a topological insulator revealed some intrinsic limitations and physical drawbacks of the technique, such as spurious effects originating from the high power pulses, like multiphoton absorption and the space charge effect, or the reduction of experimental resolution when pushing for shorter and shorter pulse durations. Some disadvantages are also connected to the current state-of-the-art in the field of ultrashort laser systems, where a trade-off needs to be found between repetition rate and laser power.
Finally, state-of-the-art experiments based on the ability to generate ultrashort pulses carrying orbital angular momentum in visible, near-infrared as well as extreme UV range will be presented. The use of these pulses opens the door to the investigation of new physical phenomena, such as probing magnetic vortices using extreme ultraviolet light from a free-electron laser or imprinting the spatial distribution of an ultrashort infrared pulse carrying orbital angular momentum onto a photoelectron wave packet.
Najdeno v: ključnih besedah
Povzetek najdenega: ...from infrared to soft X-rays. This includes high- order harmonics generation in gas (HHG), on which...
Ključne besede: ultrafast lasers, two-color experiments, photoemission, high-order harmonic generation, free-electron lasers, hot-electrons dynamics, surface science, pump-probe photoemission, ultraviolet photoemission, orbital angular momentum
Objavljeno: 02.12.2020; Ogledov: 2727; Prenosov: 100
 Polno besedilo (19,78 MB) |
2. Chemical and structural investigation of the cobalt phthalocyanineMatija Stupar, 2015, magistrsko delo Opis: In the last two decades, studies on organic molecules mimicking substances of fundamental importance in nature, like chlorophyll or hemoglobin, have attracted researchers’ attention. These molecules are building blocks for a family of materials also referred to as “organic semiconductors”. Such compounds can be implemented in numerous applications, ranging from data-storage to light harvesting. Some of their fundamental advantages include low cost, light weight, relatively easy engineering and mechanical flexibility, compatible with bending plastic substrates.
In this thesis work we investigated the chemical, structural and electronic properties of cobalt phthalocyanines (CoPc). These molecules have promising applications in the field of magnetic data storage and spintronics in general, due to the ferromagnetic properties of the cobalt atom. Several techniques like photoemission core-level spectroscopy and valence band spectroscopy, together with X-ray absorption, have been used in order to determine the CoPc properties in gaseous phase, i.e. in the absence of interaction with the surrounding environment.
Another set of experiments was devoted to the commissioning of the CITIUS time-resolved photoemission setup, that will be used in future studies of CoPc molecules on surfaces.
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Povzetek najdenega: ...with X-ray absorption, have been used in order to determine the CoPc properties in gaseous...
Ključne besede: Cobalt phthalocyanine (CoPc), photoemission spectroscopy (PES), X-ray absorption spectroscopy (XAS), synchrotron radiation, laser, high order harmonic generation (HHG), time resolved spectroscopy
Objavljeno: 29.09.2015; Ogledov: 7808; Prenosov: 272
Polno besedilo (2,96 MB) |
3. Packing patterns of silica nanoparticles on surfaces of armored polystyrene latex particlesSara Fortuna, Catheline A. L. Colard, Stefan A. F. Bon, Alessandro Troisi, 2009, izvirni znanstveni članek Opis: Fascinating packing patterns of identical spherical and discotic objects on curved surfaces occur readily in nature and science. Examples include C60 fullerenes,(1, 2)13-atom cuboctahedral metal clusters,(3) and S-layer proteins on outer cell membranes.(4) Numerous situations with surface-arranged objects of variable size also exist, such as the lenses on insect eyes, biomineralized shells on coccolithophorids,(5) and solid-stabilized emulsion droplets(6) and bubbles.(7) The influence of size variations on these packing patterns, however, is studied sparsely. Here we investigate the packing of nanosized silica particles on the surface of polystyrene latex particles fabricated by Pickering miniemulsion polymerization of submicrometer-sized armored monomer droplets. We are able to rationalize the experimental morphology and the nearest-neighbor distribution with the help of Monte Carlo simulations. We show that broadening of the nanoparticle size distribution has pronounced effects on the self-assembled equilibrium packing structures, with original 12-point dislocations or grain-boundary scars gradually fading out.
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Povzetek najdenega: ...packing patterns, silica, simulation, Monte Carlo, order, disorder, transition, armored particles, nanoparticles, Pickering emulsion...
Ključne besede: packing patterns, silica, simulation, Monte Carlo, order, disorder, transition, armored particles, nanoparticles, Pickering emulsion
Objavljeno: 10.10.2016; Ogledov: 3989; Prenosov: 0
Polno besedilo (3,85 MB) |
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5. The parameters that set word order in Slovenian Sign LanguageMatic Pavlič, 2015, objavljeni povzetek znanstvenega prispevka na konferenci Opis: The field of word order (WO) research in oral languages was opened with Greenberg (1963), who discovered that possible WOs are not evenly distributed in his sample of 30 languages. Linguists have ever since struggled to find out how do prevalent WOs emerge in the human brain (for the overview see Kemmerer 2012), how they are derived (for the overview see Dryer and Haspelmath 2013) and acquired (for the overview see Franck et al. 2013). According to Generative Grammar, basic WO is an output of the Head parameter (Chomsky 1981) and the Binarity principle (Kayne 1984). It reflects most transparently in the pragmatically unmarked surface order of subject, object and verb. The research on WO in sign languages (for the overview see Leeson and Saeed 2012) focused on exceptions, that may be triggered by modality specific factors: spacial verb-argument agreement, semantic
reversibility and iconicity. In this paper I provide the first description of Slovenian Sign Language (SZJ) arguing that its basic WO is SVO. I examine overt agreement and semantic reversibility and conclude, that these phenomena do not affect WO in SZJ. In the second part, I discuss non-basic SZJ WO that appears in role-shifting and classffer constructions due to the presence of verb-incorporated object classffers. All examples are from SZJ, elicited from L1 SZJ signers by Picture Description Task (see Volterra et al. 1984).
Najdeno v: ključnih besedah
Ključne besede: Word order, Slovenian Sign Language, classifier predicate
Objavljeno: 07.11.2017; Ogledov: 3954; Prenosov: 0
Polno besedilo (452,39 KB) |
6. Classifier predicate as a small clause in Slovenian Sign LanguageMatic Pavlič, 2017, objavljeni povzetek znanstvenega prispevka na konferenci Opis: In Slovenian Sign Language (SZJ), classifier predicate cannot be negated and thus it does not qualify as the head of a verb phrase. Such a conclusion does not rule out the possibility that SZJ classifier predicate projects a reduced clausal structure. I analyze these SZJ classifier predicates as non-verbal predicates that form a small-clause structure assuming that classifier small clause is selected by an overt (HAVE) or a covert verbal head. This proposal explains the complexity of classifier predicates. Being a non-verbal projection, classifier predicate fails to move with a verbal V-to-T movement and stays in situ. For SVO languages such as SZJ, this analysis correctly predicts the change from the basic SVO to the non-basic SOV for transitive classifier predicates and from the basic SVOdOi to the non-basic SOdVOi for ditransitive classifier predicates.
Najdeno v: ključnih besedah
Ključne besede: Slovenian Sign Language, classifier predicate, small clause, word order
Objavljeno: 10.11.2017; Ogledov: 3751; Prenosov: 0
Polno besedilo (69,48 KB) |
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9. Omidi, Saber; Davvaz, Bijan Convex ordered Γ-semi hypergroups associated to strongly regular relations. Matematika (Johor) 33 (2017), no. 2, 227–240.Irina Cristea, 2018, recenzija, prikaz knjige, kritika Najdeno v: ključnih besedah
Povzetek najdenega: ...convex order, strongly regular relations, Gamma-semihypergroups...
Ključne besede: convex order, strongly regular relations, Gamma-semihypergroups
Objavljeno: 30.10.2018; Ogledov: 2547; Prenosov: 0
Polno besedilo (91,84 KB) |
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