167 research outputs found
Conjugated Polymers for Energy Production:Finding Suitable Candidates for Low Cost Solar Cells
From 3,3,4,4-Tetraethoxybut-1-yne to furan derivatives
The starting material for this project was the highly functionalized compound 3,3,4,4- tetraethoxybut-1-yne (TEB) and it can be prepared from ethyl vinyl ether by a 4-steps synthesis. The third and the fourth step in TEB synthesis were sensitive to reaction conditions, so it was developed a strategy to try to optimize the third step and obtain TEB with higher yields. An approach, which tries to optimize also the fourth step, will be developed in further works.
Several γ-hydroxy-α,β-unsaturated acetylenic ketones can be prepared from 3,3,4,4- tetraethoxybut-1-yne. TEB and γ-hydroxy-α,β-unsaturated acetylenic ketones have been previously synthesized in good yields using various reaction routes.
In this work will be shown the synthesis of 1,1-diethoxy-5-hydroxyhex-3-yn-2-one, 1,1-diethoxy-5-hydroxyundec-3-yn-2-one and 1,1-diethoxy-5-hydroxydodec-3-yn-2-one, which will react with ethyl acetoacetate to give, respectively, ethyl 4-(3,3-diethoxy-2-oxopropyl)-2,5-dimethylfuran-3-carboxylate, ethyl 4-(3,3-diethoxy-2-oxopropyl)-5-hexyl-2-methylfuran-3-carboxylate and ethyl 4-(3,3-diethoxy-2-oxopropyl)- 5-heptyl-2-methylfuran-3-carboxylate furan derivatives.
This thesis project was carried out during the year 2011, at the Department of Chemistry of the University of Bergen
Covariant Lyapunov vectors
The recent years have witnessed a growing interest for covariant Lyapunov
vectors (CLVs) which span local intrinsic directions in the phase space of
chaotic systems. Here we review the basic results of ergodic theory, with a
specific reference to the implications of Oseledets' theorem for the properties
of the CLVs. We then present a detailed description of a "dynamical" algorithm
to compute the CLVs and show that it generically converges exponentially in
time. We also discuss its numerical performance and compare it with other
algorithms presented in literature. We finally illustrate how CLVs can be used
to quantify deviations from hyperbolicity with reference to a dissipative
system (a chain of H\'enon maps) and a Hamiltonian model (a Fermi-Pasta-Ulam
chain)
Intertangled stochastic motifs in networks of excitatory-inhibitory units
We have benefited from discussions with A. Politi. The authors acknowledge financial support from H2020- MSCA-ITN-2015 project COSMOS 642563.Peer reviewedPostprin
New quantum simulations with ultracold Ytterbium gases
In recent years, the unprecedented experimental control of the laws of quantum mechanics has led to the so-called quantum technology revolution, a terminology adopted to refer to the applications in which quantum properties play a prominent role. Also the fundamental physics has benefited from these advancements with the development of quantum simulators, controlled quantum platforms engineered in such a way to emulate the physics of complex systems difficult to investigate with classical approaches. The present work deals with the simulation of some fundamental properties of quantum-Hall systems by means of degenerate fermionic Ytterbium atoms confined in artificial periodic potentials. Extreme regimes, inaccessible to real solid-state system, have been explored, paving the way to the observation of exotic phases of matter
Differential neural dynamics underling pragmatic and semantic affordance processing in macaque ventral premotor cortex
Premotor neurons play a fundamental role in transforming physical properties of observed objects, such as size and shape, into motor plans for grasping them, hence contributing to "pragmatic" affordance processing. Premotor neurons can also contribute to "semantic" affordance processing, as they can discharge differently even to pragmatically identical objects depending on their behavioural relevance for the observer (i.e. edible or inedible objects). Here, we compared the response of monkey ventral premotor area F5 neurons tested during pragmatic (PT) or semantic (ST) visuomotor tasks. Object presentation responses in ST showed shorter latency and lower object selectivity than in PT. Furthermore, we found a difference between a transient representation of semantic affordances and a sustained representation of pragmatic affordances at both the single neuron and population level. Indeed, responses in ST returned to baseline within 0.5 s whereas in PT they showed the typical sustained visual-to-motor activity during Go trials. In contrast, during No-go trials, the time course of pragmatic and semantic information processing was similar. These findings suggest that premotor cortex generates different dynamics depending on pragmatic and semantic information provided by the context in which the to-be-grasped object is presented
Desynchronization and pattern formation in a noisy feed-forward oscillator network
The authors acknowledge financial support from H2020-MSCA-ITN-2015 project COSMOS 642563. We thank Arkady Pikovsky for useful comments.Peer reviewedPostprin
Noise-driven neuromorphic tuned amplifier
Acknowledgments The authors acknowledge financial support from H2020-MSCA-ITN-2015 project COSMOS 642563.Peer reviewedPublisher PD
Reconstruction scheme for excitatory and inhibitory dynamics with quenched disorder: application to zebrafish imaging
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