This paper presents design considerations for an integrated wireless power transfer (WPT) and power line communication (PLC) system (e.g. WPT-PLC). The main goal is to enable wireless charging of mobile electronic products, along with high data rate communication over the shared wireless inductive resonant channel. Starting from a couple of resonant coils, characterized by the S-parameters matrix, the design of an impedance matching network and decoupling filters is carried out to better decouple power and data signals. A pulse-driven class-E power amplifier (PA) and a rectifier are first conceived based on the measured S-parameters and load-pull characterizations. Second, a sine-driven class-E power link, operating at 6.78 MHz, is proposed to reduce the total harmonic distortion of the integrated WPT-PLC system. These design steps aim to ensure high-power efficiency and low harmonic distortion of the class-E PA in order to mildly affect the channel capacity of the PLC. The harmonic interferences of the pulse-driven and sine-driven class-E power links are compared and discussed, together with the electromagnetic compatibility levels, the channel capacity, and the noise disturbances of the PLC channel in order to guarantee an optimized power and data transfer in the integrated WPT-PLC system.

In the economics literature, there are two dominant approaches for solving models with optimal experimentation (also called active learning). The first approach is based on the value function and the second on an approximation method. In principle the value function approach is the preferred method. However, it suffers from the curse of dimensionality and is only applicable to small problems with a limited number of policy variables. The approximation method allows for a computationally larger class of models, but may produce results that deviate from the optimal solution. Our simulations indicate that when the effects of learning are limited, the differences may be small. However, when there is sufficient scope for learning, the value function solution seems more aggressive in the use of the policy variable.

OBJECTIVES/SPECIFIC AIMS: Middle ear volume (MEV) is a clinically relevant parameter in the treatment of many common conditions including otitis media, tinnitus, and conductive hearing loss. A growing number of studies have shifted from using tympanometry to 3-dimensional volume reconstruction (3DVR) to calculate MEV; however, MEV values between these methodologies have never before been directly compared. Here, our objective is to characterize agreement between MEV measurement methods across disease states and middle ear sizes. METHODS/STUDY POPULATION: Middle ears were identified from 36 patients ranging 18–89 years of age who underwent tympanometry testing during preoperative workup for tympanic membrane (TM) perforation, up to 1 month prior to a standard-of-care temporal bone computed tomography (CT) between October 15, 2005 and October 15, 2015. MEV values calculated by both tympanometry and 3DVR were analyzed for agreement using Bland and Altman plots. A correction factor was calculated where ear canal volumes were available for contralateral middle ears without TM perforation (n=12), and was applied to a second Bland and Altman plot in the corresponding patient subgroup. MEV agreement was characterized across MEV quartiles (1=smallest; 4=largest) and across increasing states of middle ear disease using Kruskal-Wallis and Wilcoxon testing with Bonferonni correction. RESULTS/ANTICIPATED RESULTS: A Bland Altman plot demonstrated significant disagreement of MEV differences as compared to a priori clinical thresholds. Absolute MEV difference was significantly greater in the average MEV fourth to first quartile (p=0.0024), fourth to second quartile (p=0.0024), third to first quartile (p=0.0048), and third to second quartile (p=0.048). Absolute MEV difference was not significantly different across varying states of middle ear disease (p=0.44). DISCUSSION/SIGNIFICANCE OF IMPACT: Statistically evident and clinically significant disagreement was demonstrated across tympanometric and 3DVR MEV estimates. This lack of agreement was most pronounced at higher average MEV and was persistent yet not appreciably different across varying severities of middle ear disease. These findings may limit the generalizability of studies of the middle ear that differ in MEV estimation methodology, particularly in pathophysiological states where MEV is increased.

We discuss the expected polarization of the Galactic foregrounds at the SPOrt experiment frequencies 22-90 GHz. We also consider the problem of foreground separation and perform an analysis to estimate their impact on the detection of a cosmological signal.

The goal of the Sky Polarisation Observatory (SPOrt) Program is the measurement of the sky linearly polarised emission in the 22-90 GHz frequency range from the International Space Station (2003-2004). The instrument configuration together with most relevant ground support activities are presented. In particular, the development of hardware solutions for high sensitive polarimetric measurements has been addressed by the SPOrt team to match the experiment requirements.

Amorphous silicon-based phototransistors are studied as an alternative solution to replace pixel-level amplifiers simplifying large-area imaging systems. We report electrical characterization by means of current-voltage and capacitance measurements. The measured capacitance increases with decreasing frequency of the probe signal and values largely exceeding the geometrical one at low frequencies have been achieved both in the dark and under illumination. In particular, values in excess of 200 μF/cm2 are measured under 220 μW/cm2 illumination at 600 nm at 100 mHz. The capacitance dependence on frequency is interpreted in terms of trapping and release kinetics processes in the base and of the gain of the device.

In this work we investigate the density of states at amorphous-crystalline silicon interface that play the key role in the heterostructure solar cell application. In particular we analyzed the defect density arising from plasma treatment of the crystalline surface. This process is useful to clean the crystalline surface, but greatly influenced the electrical properties of the device. We used low temperature (20K-300K) capacitance measurement performed in a wide range of frequency of signal probe (1Hz-10kHz). Differences in the capacitance profile between samples with various plasma dry treatments indicate different defect density profile at interface. With the aid of a finite difference model of the capacitance as a function of temperature and frequency we extract information from the measurements about the defect energy distribution at interface. As a result, the density and the nature of defects at interface will be correlated to the technological parameters as: wafer cleaning procedure, hydrogen plasma treatment, type and concentration of dopants at interface.

In this work we study the possibility to use amorphous silicon nitride, grown by plasma, as an alternative way to realize buffer layer in a-Si:H/c-Si heterostructure. We experimented several growing condition for silicon nitride depending on deposition parameters, obtaining samples highly transparent and with optical gap varying in the range 2.4 – 5.2 eV. We found evidence that the gap of the material is principally due to the NH3/N2 ratio. The very low absorption obtainable on this material was successfully utilized to increase the short circuit current density of the device respect to the standard cell with intrinsic amorphous silicon buffer, particularly in the low wavelength region as confirmed by quantum yield measurements. We optimized the thickness of the SiNx buffer layer respect to the photovoltaic parameters of the solar cell. A 0.5 nm thick SiNx ensures good photogeneration in blue region of the visible spectrum and does not appreciably degrade the transport mechanism of the heterojunction.

In this paper we present an innovative diode based on the heterojunction between amorphous silicon and porous silicon grown on crystalline silicon. The device architecture gives several advantages. Deposition of amorphous silicon on porous material realises high performance junction at temperature less than 250°C and it passives the porous layer against the natural oxidation due to ageing in the environment. Porous technology allows to obtain a controlled textured silicon surface independently from crystalline silicon orientation just to give the opportunity to reduce surface reflectivity and the blue shift of the absorption spectra in solar cell application. Solar cells were characterised by I-V dark/light and quantum yield measurements. Under standard AM 1.5 light we obtained photovoltaic conversion efficiency greater than 10%. Change in photoluminescence in different gas environments showed for gas sensor applications give rise encouraging results. In dark condition we found the typical diode behaviour.

In this work we demonstrate that radiation up to 2 μm induces photocurrent in a single junction amorphous silicon structure at room temperature. The absorber layer is a microcompensated film deposited using very low concentrations of dopant species. Device operation is based on optical excitation of thermal generated carriers from trap states toward valence and conduction band in the high electric field region of the structure. Transient and frequency response under different bias voltages and illuminations conditions are presented. The possibility to use the infrared sensor in low bit rate communication systems has been demostrated by including our detector in a front-end system and measuring its frequency responce.

Quantum efficiency measurement have been reproduced with a numerical model, able to take into account sub-band gap absorption into single films. Model results indicate the presence of a large valence band tail and a high number of dangling bonds and shallow defects ascribed to the presence of dopant atoms.

The development of a hybrid heterojunction fabricated by growing ultrathin amorphous silicon by Plasma Enhanced Chemical Vapor Deposition using temperatures below 250°C offers the potential of obtaining high efficiency solar cells deposited on glassy substrates. The surface preparation represents one of the most critical steps. The first aim of etching is to remove the native oxide layer from the surface of the crystalline wafer, before amorphous layer deposition. The possibility of obtaining this goal with a dry procedure that reduces the exposure of the sample to the environment is not trivial.

We performed several dry etching processes but the best results were obtained using an etching process involving CF4/O2 gases. We have found evidence that plasma etching acts by removing the native oxide and the damaged surface of textured silicon and by leaving an active layer on silicon surface suitable for the emitter deposition. SEM analysis has confirmed that it is possible to find plasma process conditions where no appreciable damage and changes in surface morphology are induced. Detailed investigation was performed to find compatibility and optimization of amorphous layer deposition both on flat and textured cast silicon by changing the plasma process parameters. By using this process we achieved on cast silicon for solar applications photovoltaic conversion efficiencies of 12.9% on 51 cm2 and 9.2% on 45 cm2 active areas for amorphous crystalline heterostructure devices realized on monocrystalline and polycrystalline silicon respectively. We also investigated the compatibility of the process with industrial production of large area devices.

In this work we study the effects of material properties on the reading process of color detectors by using a two dimensional simulator for the transient regime. In particular, starting from the potential and charge distribution in the device, we describe effects of the density of defects on the self-bias process. Results show the possibility to engineer materials in order to optimize response speed of the device.

Difference in the absorption coefficient profile of the amorphous and crystalline silicon is the key idea for the realization of a new visible/infrared tunable photodetector (VIP). The device consists on a n-doped a-Si:H/intrinsic a-Si:H/p-doped a-SiC:H multilayer grown by PECVD on a p-type crystalline silicon wafer doped by a phosphourus diffusion. A grid-shaped aluminum front contact with transparent conductive oxide coating is used as window for the incident light. Tunable sensitivity in the visible and near infrared spectral range can be achieved under different values of the external voltage, with excellent spectral separation between the two quantum efficiencies peaks at 480 nm and 800 nm.

A simple analytical model taking into account the absorption profile, diffusion and drift lengths, and layer thicknesses reproduces fairly well the experimental results.

We investigated a-Si:H compensated materials deposited over a wide range of gas dopant concentrations, from 0.125 ppm up to 103 ppm.

We achieved compensation for different ratio in the gas phase of diborane and phosphine, depending on their concentration. As a relevant result, we found that at constant boron concentration compensation occurs by using two different values of phosphine flow. This behavior can be described by a change of formation mechanism involving active dopants, defects and boron-phosphorus complex, that occurs in a different way depending on the dopant concentrations.

The two compensation regimes are evidenced also by a different behavior under light soaking. Furthermore we found that photocurrent evolution under illumination is determined by two concurrent mechanisms: activation of dopant species and increase of defect density.

In this paper we focus our attention on compensated materials with μ-doping concentration in order to obtain a stable intrinsic layer with initial high photoconductivity suitable for p-i-n solar cells. Films were grown from a mixture of undiluted silane, hydrogen diluted phosphine and hydrogen diluted diborane. Values of dark conductivity around 10-11 Ω-1cm-1 and photosensitivity ratio under AM 1.5 of 6 orders of magnitude have been obtained for phosphine/diborane ratio around 102. The difference between the two dopant concentrations is in agreement with the difference in doping efficiency of the two gases found in the characterization of single μ-doped films.

We compared the degradation behavior of compensated and intrinsic materials with the same initial dark and light conductivity. After about 20 h the photoconductivity of the compensated and the intrinsic material decreased of 33% and 70%, respectively. The space of investigable deposition parameters has been limited by the stress induced by the simultaneous presence of phosphine and diborane which leads to a macroscopic, periodic and regular damage of the film.