Polytechnic University of Milan

About: Polytechnic University of Milan is a education organization based out in Milan, Italy. It is known for research contribution in the topics: Finite element method & Population. The organization has 18231 authors who have published 58416 publications receiving 1229711 citations. The organization is also known as: PoliMi & L-NESS.

Interaction of Water with the Model Ionic Liquid [bmim][BF4]: Molecular Dynamics Simulations and Comparison with NMR Data

Abstract: We report on molecular dynamics simulations of the ionic liquid [bmim][BF4] and its mixtures with water, from zero up to 0.5 mol fraction of water. All of the simulations are carried out with two published force fields. The results are compared with each other and with published as well as new NMR data on the same mixtures, whenever possible. We perform extensive analyses of structural quantities, such as pair correlation functions, nearest-neighbor analysis and size distribution of the water clusters formed at higher concentrations. We show that the water clusters are formed almost exclusively by linear chains of hydrogen-bonded molecules. There is a nanoscale structuring of the mixtures but no macroscopic phase separation among the components, in agreement with experiment. Roughly, we identify two solvation regimes. At low water content, the ions are selectively coordinated by individual water molecules, but their ionic network is largely unperturbed. At high water content, the ionic network is somewhat...

A halogen-bonding-based heteroditopic receptor for alkali metal halides.

Abstract: A new heteroditopic receptor for alkali metal halides has been designed and synthesized. It is comprised of a well-established motif for cation binding and a motif for halogen-bonding-based anion recognition processes. The single-crystal X-ray structure of the complex between the heteroditopic receptor and sodium iodide is reported. Thanks to the cooperativity of metal coordination and the strong I-···I halogen bonding, the ion pair is fully separated. The boosting effect of the binding of the anion through halogen bonding on the coordination of the cation by the receptor has been proved also in solution by NMR experiments. The selectivity of the new heterotopic receptor toward different alkali metal halides has been tested by ESI mass experiments.

Distinct Charge Orders in the Planes and Chains of Ortho-III-Ordered YBa 2 Cu 3 O 6+δ Superconductors Identified by Resonant Elastic X-ray Scattering

Abstract: Recently, charge density wave (CDW) order in the ${\mathrm{CuO}}_{2}$ planes of underdoped ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{6+\ensuremath{\delta}}$ was detected using resonant soft x-ray scattering. An important question remains: is the chain layer responsible for this charge ordering? Here, we explore the energy and polarization dependence of the resonant scattering intensity in a detwinned sample of ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{6.75}$ with ortho-III oxygen ordering in the chain layer. We show that the ortho-III CDW order in the chains is distinct from the CDW order in the planes. The ortho-III structure gives rise to a commensurate superlattice reflection at $Q=[0.33\text{ }0\text{ }L]$ whose energy and polarization dependence agrees with expectations for oxygen ordering and a spatial modulation of the Cu valence in the chains. Incommensurate peaks at [0.30 0 $L$] and [0 0.30 $L$] from the CDW order in the planes are shown to be distinct in $Q$ as well as their temperature, energy, and polarization dependence, and are thus unrelated to the structure of the chain layer. Moreover, the energy dependence of the CDW order in the planes is shown to result from a spatial modulation of energies of the Cu $2p$ to $3{d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ transition, similar to stripe-ordered 214 cuprates.

An EMG-controlled exoskeleton for hand rehabilitation

Abstract: The principal goal of this work is the development, testing and experimentation of a device for the hand rehabilitation. The system we designed is intended for people who have partially lost the ability to control correctly the hand musculature, for example after a stroke or a spinal cord injure. Based on EMG signals the system can "understand" the subject volition to move the hand and thanks to its actuators can help the fingers movement in order to perform the task. In this paper we describe the device and discuss the first results conducted on a healthy volunteer.