Search results for "transition"
showing 10 items of 3988 documents
Strongly Coupled Coherent Phonons in Single-Layer MoS 2
2019
We present a transient absorption setup combining broadband detection over the visible-UV range with high temporal resolution ($\sim$20fs) which is ideally suited to trigger and detect vibrational coherences in different classes of materials. We generate and detect coherent phonons (CPs) in single layer (1L) MoS$_2$, as a representative semiconducting 1L-transition metal dichalcogenide (TMD), where the confined dynamical interaction between excitons and phonons is unexplored. The coherent oscillatory motion of the out-of-plane $A'_{1}$ phonons, triggered by the ultrashort laser pulses, dynamically modulates the excitonic resonances on a timescale of few tens fs. We observe an enhancement by…
Profiles of reading and fluency and spelling skills : stability and change across the early school years
2023
In this longitudinal study, we examined what kind of profiles of reading fluency and spelling skills could be identified among pupils (N = 467) and how stable these profiles were during the first three years of school. We also investigated how monolingual (Swedish) and simultaneously bilingual (Finnish-Swedish) pupils and gender were distributed within the profiles. Three profiles of reading fluency and spelling skills were found among the pupils through latent profile analysis: low, average, and high performing. Latent transition analysis confirmed stable and identical profiles throughout the first school years. The distributions of monolingual and bilingual pupils and gender were equal in…
Progression of Diiminopyridines: From Single Application to Catalytic Versatility
2015
Diiminopyridyl metal complexes, first characterized several decades ago, found practical application in 1998 when they were used as precatalysts in coordinative ethylene polymerization. This discovery contributed to the so-called postmetallocene revolution and triggered the large-scale experimental and theoretical research aimed at understanding diversified diiminopyridine chemistry. The results of this quest, some of which were intriguing and difficult to anticipate, are discussed and summarized in the current Review.
Potential-assisted deposition of mixed alkanethiol self-assembled monolayers
2010
Abstract Preparation of self-assembled monolayers (SAMs) usually involves passive incubation. The recently developed potential-assisted deposition is indeed more selective as well as 100-fold faster than passive adsorption, thereby enhancing the reproducibility of the monolayer deposition. This article aims to identify the electrodeposition conditions necessary to prepare mixed alkanethiol SAMs on gold surface. Parameters such as concentrations in solution, electrode polarization and deposition time were examined for two chain lengths, C 3 (mercaptopropionic acid, MPA) and C 18 (octadecanethiol, ODT). The kinetics and composition of the SAMs were systematically characterized by reductive st…
SUSTAINABILITY AND ENVIRONMENTAL TRANSITION: PRINCIPLES AND DESIGN GUIDELINES
2021
In these times of constant precariousness and insecurity, debates on the need for environmental sustainability are on the increase. There is a need to regenerate urban areas both by transforming the existing heritage while respecting historical memory, and by proposing "renewed" neighbourhoods with smartness, according to the use of renewable energy sources, eco-building, intelligent mobility, with a view to ecological transition. Immediate responses are needed to resource depletion on the one hand and the need to protect the quality of natural and environmental capital on the other. To achieve these goals, cities are called upon to play the role of drivers of sustainable development. By en…
GREEN REVOLUTION AND BUILT HERITAGE: CONCEPTS AND PERSPECTIVES OF ENVIRONMENTAL REGENERATION
2021
Urban and environmental regeneration is now a priority on a planetary level, and the climate neutrality objectives set by Brussels inevitably require a new green and sustainable design of cities and a total revision of human behaviour in relation to nature. Environmental regeneration requires an inclusive practice of architecture capable of metabolising the adaptations and contradictions of the built environment. With this in mind, and with no claim to being exhaustive, we will examine some of the "enabling" conditions and "indispensable" reasons for leading a process of environmental regeneration of the built heritage, analysing the critical points relating to public responsibilities, the …
Stability and transitions in school-aged children's physical education need satisfaction profiles : A latent transition analysis
2022
This study examined stability and transitions of school-aged children's self-determination theory-based need satisfaction profiles in physical education (PE) over three years. Participants were 1121 (girls 573, boys 548) Finnish school children. The self-report data were assessed using identical procedures from 2017 to 2020. Three latent need satisfaction profiles were identified: Low, Mid, and High need satisfactions. Transitions mainly occurred between grade 5 and 6 in elementary school, after which the profile memberships remained relatively stable. The profile memberships were not school- or PE group dependent over time. These results indicate that school-based actions to achieve a posi…
Farming on the margins : Just transition and the resilience of peripheral farms
2022
Sustainability transition demands fundamental changes taking place at the farm system level. At the same time, many farms are operating on the verge of financial profitability, especially in geographically disadvantaged peripheral regions with a limited range of production opportunities. These observations raise concerns about the transition's justice aspects. Using the concept of resilience, we analysed farmers’ capacities for transformation in a peripheral context in Finland. The results from our farmer survey (n = 577) indicated that the regime exerts a strong cost-price squeeze on farmers, escaping of which is difficult also for farmers deliberately seeking new pathways beyond it. Due t…
Transitions through the dynamics of adaptive cycles : Evolution of the Finnish agrifood system
2023
CONTEXT The escalating sustainability problems of the current agrifood regime call for a radical, systemic transformation. Such a transformation implies a move into a new stability domain, defined by a new set of systemic attractors. These transformations can be conceptualised as regime shifts. OBJECTIVE In this study, we explored the history of the Finnish agrifood system in order to learn from the past transformations of the system and to inform the current attempts to steer its development in a more sustainable direction. METHODS We conducted a qualitative analysis on literature discussing the history of the Finnish agrifood system by utilising the concept of the adaptive cycle, which ca…
Some remarks on Landau's (macroscopic) phase transition theory
2012
This paper explain the existence of a particular formal model (drew from Theoretical Astrophysics) whose thermodynamical phenomenology shows a possible second order phase transition (according to Landau’s Thermodynamical Theory) that seems does not verify the (Birman-Goldrich-Jaric) ”chain subduction criterion” and the (Ascher’s) ”maximality criterion” of Landau’s Phenomenological Theory. Therefore, it follows that Landau’s Phenomenological Theory is more restrictive than the Landau’s Thermodynamical Theory.