Surface doping in T6/ PDI-8CN2 Heterostructures investigated by transport and photoemission measurements

In this paper, we discuss the surface doping in sexithiophene (T6) organic field-effect transistors by PDI-8CN2. We show that an accumulation heterojunction is formed at the interface between the organic semiconductors and that the consequent band bending in T6 caused by PDI-8CN2 deposition can be addressed as the cause of the surface doping in T6 transistors. Several evidences of this phenomenon have been furnished both by electrical transport and photoemission measurements, namely the increase in the conductivity, the shift of the threshold voltage and the shift of the T6 HOMO peak towards higher binding energies.Comment: 5 pages, 5 figure

Prospects for detecting Gamma-Ray Bursts with the Cherenkov Telescope Array

The Large Area Telescope (LAT) on the Fermi gamma-ray satellite telescope observes Gamma-Ray Bursts (GRBs) at energies above 100 MeV. Thanks to a new detection algorithm and a new event reconstruction, it is expected to publish a catalogue with more than 100 GRBs. This work aims at revising the prospects for GRB alerts with the Cherenkov Telescope Array (CTA) based on the new LAT results. We start by considering the simulation of the observations with the full CTA of two extremely bright events, the long GRB 130427A and the short GRB 090510; then we investigate how these GRBs would be observed by different subsamples of the array pointing to different directions, adopting the \u201ccoupled divergent\u201d mode

Single-Crystal Organic Charge-Transfer Interfaces probed using Schottky-Gated Heterostructures

Organic semiconductors based on small conjugated molecules generally behave as insulators when undoped, but the hetero-interfaces of two such materials can show electrical conductivity as large as in a metal. Although charge transfer is commonly invoked to explain the phenomenon, the details of the process and the nature of the interfacial charge carriers remain largely unexplored. Here we use Schottky-gated heterostructures to probe the conducting layer at the interface between rubrene and PDIF-CN2 single crystals. Gate-modulated conductivity measurements demonstrate that interfacial transport is due to electrons, whose mobility exhibits band-like behavior from room temperature to ~ 150 K, and remains as high as ~ 1 cm2V-1s-1 at 30 K for the best devices. The electron density decreases linearly with decreasing temperature, an observation that can be explained quantitatively based on the heterostructure band diagram. These results elucidate the electronic structure of rubrene-PDIF-CN2 interfaces and show the potential of Schottky-gated organic heterostructures for the investigation of transport in molecular semiconductors.Comment: 37 pages, 9 Figures (including supplementary information

Fixture-abutment connection surface and micro-gap measurements by 3D micro-tomographic technique analysis

X-ray micro-tomography (micro-CT) is a miniaturized form of conventional computed axial tomography (CAT) able to investigate small radio-opaque objects at a-few-microns high resolution, in a non-destructive, non-invasive, and tri-dimensional way. Compared to traditional optical and electron microscopy techniques, which provide two-dimensional images, this innovative investigation technology enables a sample tri-dimensional analysis without cutting, coating or exposing the object to any particular chemical treatment. X-ray micro-tomography matches ideal 3D microscopy features: the possibility of investigating an object in natural conditions and without any preparation or alteration; non-invasive, non-destructive, and sufficiently magnified 3D reconstruction; reliable measurement of numeric data of the internal structure (morphology, structure and ultra-structure). Hence, this technique has multi-fold applications in a wide range of fields, not only in medical and odontostomatologic areas, but also in biomedical engineering, materials science, biology, electronics, geology, archaeology, oil industry, and semi-conductors industry. This study shows possible applications of micro-CT in dental implantology to analyze 3D micro-features of dental implant to abutment interface. Indeed, implant-abutment misfit is known to increase mechanical stress on connection structures and surrounding bone tissue. This condition may cause not only screw preload loss or screw fracture, but also biological issues in peri-implant tissues

Vestibulo-Ocular Reflex Modification after Virtual Environment Exposure

Immersion in an illusory world is possible by means of virtual reality (VR), where environmental perception is modi bff c1c ed by artificial sensorial stimulation. The application of VR for the assessment and rehabilitation of pathologies affecting the vestibular system, in terms of both diagnosis and care, could represent an interesting new line of research. Our perception of reality is in fact based on static and dynamic spatial information perceived by our senses. During head movements in a virtual environment the images on the display and the labyrinthine information relative to the head angular accelerations differ and therefore a visuo-vestibular conflict is present. It is known that mismatches between visual and labyrinthine information may modify the vestibulo-oculomotor reflex (VOR) gain. We studied the post-immersion modifications in 20 healthy subjects (mean age 25 years) exposed to a virtual environment for 20 min by wearing a head-mounted display. VOR gain and phase were measured by means of harmonic sinusoidal stimulation in the dark before, at the end of and 30 min after VR exposure. A VOR gain reduction was observed in all subjects at the end of VR exposure which disappeared after 30 min. Our data show that exposure to a virtual environment can induce a temporary modi bff c1c cation of the VOR gain. This bff c1c nding can be employed to enable an artificial, instrumental modification of the VOR gain and therefore opens up new perspectives in the assessment and rehabilitation of vestibular diseases

Evaluation of municipal waste incineration impact on environmental noise

The EU Directive 2002/49/EC or Environmental Noise Directive (END) aims to define a common approach intended to avoid, prevent or reduce the harmful effects, including annoyance, due to exposure to environmental noise. Under this Directive, member states are obliged to produce the noise maps of the major roads, railways airports, large agglomerations and industrial activity sites. The first maps had to be produced for the main agglomerations by July 2007 and the first action plans should be activated no lather than July 2008. In this work we consider the industrial noise produced by municipal waste incineration; the study was developed to provide data of the sound power level along the facades buildings and contours of this site that can be used to produce strategic noise maps. To characterize the impact of the waste incineration plant, measurements of the noise emissions were performed in situ. The distribution of sound power and sound input levels have been calculated by SoundPLAN\uae computer model. The results of this work can provide a re-applicable method for the production of noise levels due to industrial noise sources. The results are suitable to be included in noise maps for agglomerations, in line with the END expectatio

Assessment of Trends and Uncertainties in the Atmospheric Boundary Layer Height Estimated Using Radiosounding Observations over Europe

Trends in atmospheric boundary layer height may represent an indication of climate changes. The related modified interaction between the surface and free atmosphere affects both thermodynamics variables and dilution of chemical constituents. Boundary layer is also a major player in various feedback mechanisms of interest for climate models. This paper investigates trends in the nocturnal and convective boundary layer height at mid-latitudes in Europe using radiosounding profiles from the Integrated Global Radiosounding Archive (IGRA). Atmospheric data from the European Centre for Medium-Range Weather Forecasts (ECMWF) ReAnalysis v5 (ERA5) and from the GCOS Reference Upper-Air Network (GRUAN) Lindenberg station are used as intercomparison datasets for the study of structural and parametric uncertainties in the trend analysis. Trends are calculated after the removal of the lag-1 autocorrelation term for each time series. The study confirms the large differences reported in literature between the boundary layer height estimates obtained with the two different algorithms used for IGRA and ERA5 data: ERA5 shows a density distribution with median values of 350 m and 1150 m for the night and the daytime data, respectively, while the corresponding IGRA median values are of 1150 m and 1750 m. An overall good agreement between the estimated trends is found for nighttime data, while daytime ERA5 boundary layer height estimates over Europe are characterized by a lower spatial homogeneity than IGRA. Parametric uncertainties due to missing data in both the time and space domain are also investigated: the former is not exceeding 1.5 m, while the latter are within 10 m during night and 17 m during the day. Recommendations on dataset filtering based on time series completeness are provided. Finally, the comparison between the Lindenberg data as processed at high-resolution by GRUAN and as provided to IGRA at a lower resolution, shows the significant impact of using high-resolution data in the determination of the boundary layer height, with differences from about 200 m to 450 m for both night and day, as well as a large deviation in the estimated trend