Search results for "Length"
showing 10 items of 2188 documents
Polarization Insensitive Wavelength Conversion in a Low-Birefringence SiGe Waveguide
2016
We report the first demonstration of a single-pass dual-orthogonal-pump four-wave mixing-based wavelength conversion scheme in a silicon-based waveguide. The silicon germanium waveguide used was designed to exhibit strong TE/TM mode similarity across a broad wavelength range as well as a large nonlinear coefficient. A polarization-dependent loss of just 0.42 dB was measured, and the conversion of 40-Gb/s differential phase-shift keying signals was demonstrated with 1.5-dB power penalty at a bit error ratio of $10^{-9}$ .
Low-cost high-haze films based on ZnO nanorods for light scattering in thin c-Si solar cells
2015
Light scattering from ZnO nanorods (NR) is investigated, modeled, and applied to a solar cell. ZnO NR (120-1300 nm long, 280-60 nm large), grown by low-cost chemical bath deposition at 90 degrees C, exhibit diffused-to-total transmitted light as high as 70% and 30% in the 400 and 1000 nm wavelength range, respectively. Data and scattering simulation show that ZnO NR length plays a crucial role in light diffusion effect. A transparent ZnO NR film grown on glass and placed on top of a 1 mu m thick c-Si solar cell is shown to enhance the light-current conversion efficiency for wavelengths longer than 600 nm. (C) 2015 AIP Publishing LLC.
Towards an analytical framework for tailoring supercontinuum generation.
2016
A fully analytical toolbox for supercontinuum generation relying on scenarios without pulse splitting is presented. Furthermore, starting from the new insights provided by this formalism about the physical nature of direct and cascaded dispersive wave emission, a unified description of this radiation in both normal and anomalous dispersion regimes is derived. Previously unidentified physics of broadband spectra reported in earlier works is successfully explained on this basis. Finally, a foundry-compatible few-millimeters-long silicon waveguide allowing octave-spanning supercontinuum generation pumped at telecom wavelengths in the normal dispersion regime is designed, hence showcasing the p…
Optical retarder system with programmable spectral retardance.
2014
An optical system that works as a retarder waveplate with programmable spectral retardance is proposed. The system is based on a pixelated liquid crystal on silicon (LCoS) spatial light modulator (SLM). The input light beam is spectrally dispersed and different spectral components are projected onto different pixels of the LCoS-SLM. A different retardance is then addressed for each pixel, adapted to the incoming wavelength. Light reflected from the SLM is then recombined by the same setup. In this way a programmable polarization spectrum can be encoded. We illustrate the broadband characterization that is required for proper use of the system. Then several examples are shown, including spec…
Plasmonic Focusing Reduces Ensemble Linewidth of Silver-Coated Gold Nanorods
2008
Silver coating gold nanorods reduces the ensemble plasmon line width by changing the relation connecting particle shape and plasmon resonance wavelength. This change, we term "plasmonic focusing", leads to less variation of resonance wavelengths for the same particle size distribution. We also find smaller single particle linewidth comparing resonances at the same wavelength but show that this does not contribute to the ensemble linewidth narrowing.
Epidemiology of intensive care unit-acquired sepsis in Italy: Results of the SPIN-UTI network
2018
Background. Sepsis is the major cause of mortality from any infectious disease worldwide. Sepsis may be the result of a healthcare associated infection (HAI): the most frequent adverse events during care delivery especially in Intensive Care Units (ICUs). The main aim of the present study was to describe the epidemiology of ICU-acquired sepsis and related outcomes among patients enrolled in the framework of the Italian Nosocomial Infections Surveillance in ICUs - SPIN-UTI project. Study design. Prospective multicenter study. Methods. The SPIN-UTI network adopted the European protocols for patient-based HAI surveillance. Results. During the five editions of the SPIN-UTI project, from 2008 to…
Predicting soil loss on moderate slopes using an empirical model for sediment concentration
2011
Summary The objective of this investigation was to estimate event soil loss per unit area from bare plots in central and southern Italy using an empirical model for sediment concentration. The analysis was developed using data collected on bare plots differing in length (11–44 m) and slope (10–26%) at three Italian stations (Masse, Umbria; Caratozzolo, Calabria; Sparacia, Sicily). At first, an analysis was carried out, using the experimental data collected at Sparacia, to establish a relationship between sediment concentration and hydrological variables, such as runoff, rainfall amount and single storm erosion index. Then, an empirical model to estimate plot soil loss as a function of rainf…
Modelling sediment delivery processes by a stream tube approach
1999
Abstract The sediment delivery processes due to the travel along a hydraulic path having an uniform slope and to the concave shape of the path are modelled. In particular, using a power equation for modelling the slope profile and RUSLE with two different expressions of the topographic factors, a criterion to define the erosion active slope length, i.e. the slope length in which no deposition processes occur, is initially proposed. Then, the RUSLE equation is adapted to concave profiles by a correction factor of the topographic factors depending on slope curvature. Finally, the deduced relationships (equations (19) and (27)) for correcting the topographic factors for a concave slope are exp…
A new expression of the slope length factor to apply USLE-MM at Sparacia experimental area (Southern Italy)
2013
Abstract Predicting soil loss due to water erosion by empirical models is useful to assess the severity of the phenomenon in an area of interest and to predict the effect of alternative soil erosion control practices. The USLE scheme cannot be used at the Sparacia experimental area (Sicily, South Italy) to predict event soil loss per unit plot area, Ae, because experimental data suggest that, generally, Ae does not increase with plot length, λ. The USLE-MM scheme uses the runoff coefficient, QR, as an additional independent variable in order to develop an empirical model allowing prediction of storm soil loss values that do not necessarily increase with λ. According to this model, Ae is exp…
Advances in designing drip irrigation laterals
2018
It is known that using paired laterals, in which two distribution pipes extend in opposite directions from a common manifold, contribute to increasing water use efficiency (WUE). Recently, an analytical procedure to optimally design paired drip laterals on uniform slopes was proposed. More recently, this design procedure was simplified by deriving simple explicit relationships, as a function of 16 calibration constants, with relative errors that were less than 2%. In this paper, further simple design relationships are derived that require only 3 calibration constants, thus more readily obtainable results are produced and the influence of the flow rate and diameter exponents of resistance eq…