335 research outputs found
Effects of Force Level and Hand Dominance on Bilateral Transfer of a Fine Motor Skill
Our research is about bilateral transfer, a concept in motor learning where skills
learned by one limb are "transferred", allowing the opposite limb to benefit from what
was learned by the first limb. Previous research into bilateral transfer has raised
questions about whether specific aspects of motor coordination are or are not
transferred. We wanted to see whether learning to control pinch force by the thumb
and index finger is transferable, and if it is, whether the learning transfers equally
from either hand. We also want to look into the effects of different force levels on
the degree of transfer. We designed a task using a program that takes force levels
as inputs and has the participant trace shapes on a screen. By having participants
perform with one hand, then practice with the other, and finally perform again with
the initial hand, we can measure transfer as the difference in performance before
and after practice with the other hand.Kinesiology and Health Educatio
Reduced dimensionality multiphysics model for efficient VCSEL optimization
The ICT scene is dominated by short-range intra-datacenter interconnects and networking, requiring high speed and stable operations at high temperatures. GaAs/AlGaAs vertical-cavity surface-emitting lasers (VCSELs) emitting at 850–980 nm have arisen as the main actors in this framework. Starting from our in-house 3D fully comprehensive VCSEL solver VENUS, in this work we present the possibility of downscaling the dimensionality of the simulation, ending up with a multiphysics 1D solver (D1ANA), which is shown to be capable of reproducing the experimental data very well. D1ANA is then extensively applied to optimize high-temperature operation, by modifying cavity detuning and distributed Bragg’s reflector lengths
Disorder-Induced Degradation of Vertical Carrier Transport in Strain-Balanced Antimony-Based Superlattices
We investigate carrier transport in gallium-free strained-balanced InAs/InAsSb type-II superlattices in the presence of positional and compositional disorder. We use a rigorous nonequilibrium Green’s function model based on fully nonlocal scattering self-energies computed in the self-consistent Born approximation and a multiband description of the electronic structure. Layer-thickness fluctuations, nonuniform antimony composition, and segregation throughout the superlattice stack lead to as-grown disordered structures that are quite different from the abrupt interface ideal superlattices. We find that regardless of its nature and cause, disorder significantly affects vertical-carrier-transport properties, by impeding the coherent propagation of carriers in the minibands. In particular, the minority-carrier hole mobility is fundamentally limited by the nonideal properties of the superlattice, namely the layer-thickness fluctuation and the nonuniform antimony distribution. Furthermore, upon reducing the temperature, holes become fully localized and transport occurs by hopping, which explains published measured detector data that demonstrates the quantum efficiency, exhibiting a very strong temperature dependence that degrades as the temperature is reduced. As a result, photodetectors that employ holes as minority carriers will be limited in performance, especially for long-wavelength infrared applications at low temperature. However, we find that minority-carrier electron mobility is largely unaffected by disorder, indicating the p-type absorbing layer as the preferred option
Analysis and Design of Plasmonic-Organic Hybrid Electro-Optic Modulators Based on Directional Couplers
We present a detailed simulation study on plasmonic-organic hybrid electro-optic modulators based on coupled symmetric or asymmetric plasmonic slots. An electro-optic polymer is exploited as an active material, and the device is compatible with a silicon photonics platform. The proposed device operates at 1550 nm wavelength, typical of data center or long-haul telecommunication systems. The device performance in terms of area, plasmonic losses, optical bandwidth, intrinsic modulation bandwidth and energy dissipation are comparable to already proposed Mach-Zehnder solutions, but with potentially better extinction ratio, coupling losses due to photonic-plasmonic transitions, and flexibility in exploiting, without any performance penalty, asymmetric slots to shift the ON and OFF states bias. Finally, the bias dependence of the modulation chirp is investigated, comparing through and cross-coupling configurations
The association between air pollution and the incidence of idiopathic pulmonary fibrosis in Northern Italy
Acute exacerbations and worsening of idiopathic pulmonary fibrosis (IPF) have been associated with exposure to ozone (O3), nitrogen dioxide (NO2) and particulate matter, but chronic exposure to air pollution might also affect the incidence of IPF. We investigated the association between chronic exposure to NO2, O3 and particulate matter with an aerodynamic diameter <10 \u3bcm (PM10) and IPF incidence in Northern Italy between 2005 and 2010. Daily predictions of PM10 concentrations were obtained from spatiotemporal models, and NO2 and O3 hourly concentrations from fixed monitoring stations. We identified areas with homogenous exposure to each pollutant. We built negative binomial models to assess the association between area-specific IPF incidence rate, estimated through administrative databases, and average overall and seasonal PM10, NO2, and 8-hour maximum O3 concentrations. Using unadjusted models, an increment of 10 \u3bcg\ub7m-3 in NO2 concentration was associated with an increase between 7.93% (95% CI 0.36-16.08%) and 8.41% (95% CI -0.23-17.80%) in IPF incidence rate, depending on the season. After adjustment for potential confounders, estimated effects were similar in magnitude, but with larger confidence intervals. Although confirmatory studies are needed, our results trace a potential association between exposure to traffic pollution and the development of IPF
Plasmonic nanorods for enhanced absorption in mid-wavelength infrared detectors
The absorption properties of HgCdTe-based infrared detectors can be greatly increased in the mid-infrared band, by incorporating nanostructured plasmonic arrays on the illuminated detector face. The array periodicity, combined with the excitation of surface plasmon-polariton stationary modes, enhances the absorption efficiency by a substantial amount, allowing to reduce in turn the HgCdTe absorption thickness
Challenges in multiphysics modeling of dual-band HgCdTe infrared detectors
We present three-dimensional simulations of HgCdTe-based focal plane arrays (FPAs) with two-color and dual-band sequential infrared pixels having realistic truncated-pyramid shape taking into account the presence of compositionally-graded transition layers. Simulations emphasize the importance of a full-wave approach to the electromagnetic problem, and the evaluations of the optical and diffusive contribution to inter-pixel crosstalk indicate the effectiveness of deep trenches to prevent diffusive crosstalk in both wavebands
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