71 research outputs found
Reversible phase transformation and doubly-charged anions at the surface of simple cubic RbC60
The simple cubic phase of a RbC60 thin film has been studied using
photoelectron spectroscopy. The simple cubic-to-dimer transition is found to be
reversible at the film surface. A sharp Fermi edge is observed and a lower
limit of 0.5 eV is found for the surface Hubbard U, pointing to a
strongly-correlated metallic character of thin-film simple cubic RbC60. A
molecular charge state is identified in the valence band and core level
photoemission spectra which arises from C602- anions and contributes to the
spectral intensity at the Fermi level.Comment: 13 pages, 3 figure
Electronic Structure Shift of Deep Nanoscale Silicon by SiO- vs. SiN-Embedding as Alternative to Impurity Doping
Conventional impurity doping of deep nanoscale silicon (dns-Si) used in ultra
large scale integration (ULSI) faces serious challenges below the 14 nm
technology node. We report on a new fundamental effect in theory and
experiment, namely the electronic structure of dns-Si experiencing energy
offsets of ca. 1 eV as a function of SiO- vs. SiN-embedding with a
few monolayers (MLs). An interface charge transfer (ICT) from dns-Si specific
to the anion type of the dielectric is at the core of this effect and arguably
nested in quantum-chemical properties of oxygen (O) and nitrogen (N) vs. Si. We
investigate the size up to which this energy offset defines the electronic
structure of dns-Si by density functional theory (DFT), considering interface
orientation, embedding layer thickness, and approximants featuring two Si
nanocrystals (NCs); one embedded in SiO and the other in SiN.
Working with synchrotron ultraviolet photoelectron spectroscopy (UPS), we use
SiO- vs. SiN-embedded Si nanowells (NWells) to obtain their energy
of the top valence band states. These results confirm our theoretical findings
and gauge an analytic model for projecting maximum dns-Si sizes for NCs,
nanowires (NWires) and NWells where the energy offset reaches full scale,
yielding to a clear preference for electrons or holes as majority carriers in
dns-Si. Our findings can replace impurity doping for n/p-type dns-Si as used in
ultra-low power electronics and ULSI, eliminating dopant-related issues such as
inelastic carrier scattering, thermal ionization, clustering, out-diffusion and
defect generation. As far as majority carrier preference is concerned, the
elimination of those issues effectively shifts the lower size limit of Si-based
ULSI devices to the crystalization limit of Si of ca. 1.5 nm and enables them
to work also under cryogenic conditions.Comment: 14 pages, 17 Figures with a total 44 graph
Lower Limb Rehabilitation in Juvenile Idiopathic Arthritis using Serious Games
Patients undergoing physical rehabilitation therapy must perform series of
exercises regularly over a long period of time to improve, or at least not to
worsen, their condition. Rehabilitation can easily become boring because of the
tedious repetition of simple exercises, which can also cause mild pain and
discomfort. As a consequence, patients often fail to follow their
rehabilitation schedule with the required regularity, thus endangering their
recovery. In the last decade, video games have become largely popular and the
availability of advanced input controllers has made them a viable approach to
make physical rehabilitation more entertaining while increasing patients
motivation. In this paper, we present a framework integrating serious games for
the lower-limb rehabilitation of children suffering from Juvenile Idiopathic
Arthritis (JIA). The framework comprises games that implement parts of the
therapeutic protocol followed by the young patients and provides modules to
tune, control, record, and analyze the therapeutic sessions. We present the
result of a preliminary validation we performed with patients at the clinic
under therapists supervision. The feedback we received has been overall very
positive both from patients, who enjoyed performing their usual therapy using
video games, and therapists, who liked how the games could keep the children
engaged and motivated while performing the usual therapeutic routine
Characterization of high-quality MgB2(0001) epitaxial films on Mg(0001)
High-grade MgB2(0001) films were grown on Mg(0001) by means of
ultra-high-vacuum molecular beam epitaxy. Low energy electron diffraction and
x-ray diffraction data indicate that thick films are formed by epitaxially
oriented grains with MgB2 bulk structure. The quality of the films allowed
angle-resolved photoemission and polarization dependent x-ray absorption
measurements. For the first time, we report the band mapping along the Gamma-A
direction and the estimation of the electron-phonon coupling constant l ~ 0.55
for the surface state electrons.Comment: 15 text pages, 6 figures Submitted for publicatio
Serious Games for Wrist Rehabilitation in Juvenile Idiopathic Arthritis
Rehabilitation is a painful and tiring process involving series of exercises
that patients must repeat over a long period. Unfortunately, patients often
grow bored, frustrated, and lose motivation making rehabilitation less
effective. In the recent years video games have been widely used to implement
rehabilitation protocols so as to make the process more entertaining, engaging
and to keep patients motivated. In this paper, we present an integrated
framework we developed for the wrist rehabilitation of patients affected by
Juvenile Idiopathic Arthritis (JIA) following a therapeutic protocol at the
Clinica Pediatrica G. e D. De Marchi. The framework comprises four video games
and a set modules that let the therapists tune and control the exercises the
games implemented, record all the patients actions, replay and analyze the
sessions. We present the result of a preliminary validation we performed with
four poliarticular JIA patients at the clinic under the supervision of the
therapists. Overall, we received good feedback both from the young patients,
who enjoyed performing known rehabilitation exercises using video games, and
therapists who were satisfied with the framework and its potentials for
engaging and motivating the patients
Synthesis and spectroscopic characterization of alkali-metal intercalated ZrSe2
We report on the synthesis and spectroscopic characterization of alkali metal intercalated ZrSe2
single crystals. ZrSe2 is produced by chemical vapour transport and then Li intercalated. Intercalation
is performed from the liquid phase (via butyllithium) and from the vapour phase. Raman
spectroscopy of intercalated ZrSe2 reveals phonon energy shifts of the Raman active A1g and
Eg phonon modes, the disappearance of two-phonon modes and new low wavenumber Raman
modes. Angle-resolved photoemission spectroscopy is used to perform a mapping of the Fermi
surface revealing an electron concentration of 4.7 × 1014 cm−2. We also perform vapour phase
intercalation of K and Cs into ZrSe2 and observe similar changes in the Raman modes as for the
Li case
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