471 research outputs found

    Microwave Irradiation Effects on Random Telegraph Signal in a MOSFET

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    We report on the change of the characteristic times of the random telegraph signal (RTS) in a MOSFET operated under microwave irradiation up to 40 GHz as the microwave field power is raised. The effect is explained by considering the time dependency of the transition probabilities due to a harmonic voltage generated by the microwave field that couples with the wires connecting the MOSFET. From the dc current excited into the MOSFET by the microwave field we determine the corresponding equivalent drain voltage. The RTS experimental data are in agreement with the prediction obtained with the model, making use of the voltage data measured with the independent dc microwave induced current. We conclude that when operating a MOSFET under microwave irradiation, as in single spin resonance detection, one has to pay attention into the effects related to microwave irradiation dependent RTS changes.Comment: 3 pages, 4 figure

    Measuring the Temperature of a Mesoscopic Quantum Electron System by means of Single Electron Statistics

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    We measure the temperature of a mesoscopic system consisting of an ultra-dilute two dimensional electron gas at the Si/SiO2Si/SiO_2 interface in a metal-oxide-semiconductor field effect transistor (MOSFET) quantum dot by means of the capture and emission of an electron in a point defect close to the interface. Contrarily to previous reports, we show that the capture and emission by point defects in Si n-MOSFETs can be temperature dependent down to 800 mK. As the finite quantum grand canonical ensemble model applies, the time domain charge fluctuation in the defect is used to determine the temperature of the few electron gas in the channel.Comment: 4 Figures (color

    Time Dependent Inelastic Emission and Capture of Localized Electrons in Si n-MOSFETs Under Microwave Irradiation

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    Microwave irradiation causes voltage fluctuations in solid state nanodevices. Such an effect is relevant in atomic electronics and nanostructures for quantum information processing, where charge or spin states are controlled by microwave fields and electrically detected. Here the variation of the characteristic times of the multiphonon capture and emission of a single electron by an interface defect in submicron MOSFETs is calculated and measured as a function of the microwave power, whose frequency of the voltage modulation is assumed to be large if compared to the inverse of the characteristic times. The variation of the characteristic times under microwave irradiation is quantitatively predicted from the microwave frequency dependent stationary current generated by the voltage fluctuations itself. The expected values agree with the experimental measurements. The coupling between the microwave field and either one or two terminals of the device is discussed. Some consequences on nanoscale device technology are drawn.Comment: 8 Figure

    EEG correlates of social interaction at distance

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    This study investigated EEG correlates of social interaction at distance between twenty-five pairs of participants who were not connected by any traditional channels of communication. Each session involved the application of 128 stimulations separated by intervals of random duration ranging from 4 to 6 seconds. One of the pair received a one-second stimulation from a light signal produced by an arrangement of red LEDs, and a simultaneous 500 Hz sinusoidal audio signal of the same length. The other member of the pair sat in an isolated sound-proof room, such that any sensory interaction between the pair was impossible. An analysis of the Event-Related Potentials associated with sensory stimulation using traditional averaging methods showed a distinct peak at approximately 300 ms, but only in the EEG activity of subjects who were directly stimulated. However, when a new algorithm was applied to the EEG activity based on the correlation between signals from all active electrodes, a weak but robust response was also detected in the EEG activity of the passive member of the pair, particularly within 9 – 10 Hz in the Alpha range. Using the Bootstrap method and the Monte Carlo emulation, this signal was found to be statistically significant

    Higher-Order Permanent Scatterers Analysis

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    The permanent scatterers (PS) technique is a multi-interferogram algorithm for DInSAR analyses developed in the late nineties to overcome the difficulties related to the conventional approach, namely, phase decorrelation and atmospheric effects. The successful application of this technology to many geophysical studies is now pushing toward further improvements and optimizations. A possible strategy to increase the number of radar targets that can be exploited for surface deformation monitoring is the adoption of parametric super-resolution algorithms that can cope with multiple scattering centres within the same resolution cell. In fact, since a PS is usually modelled as a single pointwise scatterer dominating the background clutter, radar targets having cross-range dimension exceeding a few meters can be lost (at least in C-band datasets), due to geometrical decorrelation phenomena induced in the high normal baseline interferograms of the dataset. In this paper, the mathematical framework related to higher-order SAR interferometry is presented as well as preliminary results obtained on simulated and real data. It is shown how the PS density can be increased at the price of a higher computational load

    Two-wavelength thermo-optical determination of Organic, Elemental and Brown Carbon.

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    Introduction Thermo-optical analysis (TOA) is widely adopted for the quantitative determination of Carbonaceous Aerosol in aerosol samples collected on quartz fibre filters. Nevertheless, the quantification of Elemental and Organic Carbon (EC and OC) presents several issues, as the well-known artefacts induced by the formation of pyrolytic carbon (Pyr-C) during the analysis. Furthermore, it is usually neglected the uncertainty due to the possible presence of Brown Carbon (BrC) i.e. the optically active fraction of OC produced by biomass burning and with thermic characteristics intermediate between OC and EC. Methods In (Massab\uf2 et al., 2019), a modified Sunset EC/OC Analyzer was introduced. Briefly, the unit was upgraded making possible the alternative use of a laser diode at \u3bb = 635 nm and at \u3bb = 405 nm. In this way, the optical transmittance through the sample can be monitored at both the wavelengths. Both BrC and Pyr-C absorbance increases at shorter wavelength, so the new set-up has a better sensitivity to these species. First results Massab\uf2 et al., 2019) suggested that the 2-lambda TOA could reduce the discrepancy usually observed between EC/OC quantification by the NIOSH and EUSAAR protocols (Cavalli et al., 2010). Adopting the methodology described in (Massab\uf2 et al., 2016), i.e. the coupled use of the Multi-Wavelength Absorbance Analyzer (MWAA) and of the Sunset EC/OC Analyzer, we therefore performed a new experiment based on a set of samples collected in a rural site. Half of the samples were analysed with the EUSAAR_2 and NIOSH protocols at both the wavelengths looking for OC, EC and BrC concentration values. The other sub-set was instead used to compare the TOA results on untreated and water-washed samples, again using both the laser diodes at \u3bb = 635 nm and \u3bb = 405 nm. The water-wash step removes the water-soluble compounds, which are expected to be the main responsible of the Pyr-C formation in TOA (Piazzalunga P. et al., 2011). Finally, all the samples were also analysed to quantify the Levoglucosan (1,6-Anhydro-betaglucopyranose) content. This step, performed by High Performance Anion Exchange Chromatography coupled with Pulsed Amperometric Detection(HPLC-PAD, more details in Piazzalunga A. et al., 2010), provided the quantification of this biomass burning tracer regardless of BrC thermo-optical properties. The BrC Mass Absorption Cross-section (MAC) at \u3bb = 405 nm and \u3bb = 635 nm was finally determined. Conclusions The data reduction of the described experiment is still in progress: the results will be presented and discussed at the Conference. This work has been partially financed by the National Institute of Nuclear Physics (INFN) in the frame of the TRACCIA experiments. Cavalli, F., Putaud, J. P., Viana, M., Yttri, K. E., & Gemberg, J. (2010). Toward a standardized thermal-optical protocol for measuring atmospheric Organic and Elemental Carbon: the EUSAAR protocol. Atmos. Meas. Tech., 3, 79-89. Massab\uf2, D., Altomari, A., Vernocchi, V., & Prati, P. (2019). Two-wavelength thermo-optical determination of Light Absorbing Carbon in atmospheric aerosols. Atmos. Meas. Tech. Discuss. Massab\uf2, D., Caponi, L., Bove, M. C., & Prati, P. (2016). Brown carbon and thermal-optical analysis: a correction based on optical multiwavelength apportionment of atmospheric aerosols. Atmos. Environ., 125, 119-125. Piazzalunga, A., Fermo, P., Bernardoni, V., Vecchi, R., Valli, G., & De Gregorio M. A. (2010). A simplified method for levoglucosan quantification in wintertime atmospheric particulate matter by high performance anion-exchange chromatography coupled with pulsed amperometric detection. Int. J. Environ. An. Ch., 90, 934-947. Piazzalunga, P., Bernardoni, V., Fermo, P., Valli, G., & Vecchi, R. (2011). On the effect of watersoluble compounds removal on EC quantification by TOT analysis in urban aerosol samples. Atmos. Chem. Phys., 11, 10193-10203

    A Pilot Study of Distant `Mind-Matter' Interaction with Digital Photography

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    This pilot study explored the possibility of (a) mentally producing, at a geographical distance, predefined images on digital sensors within modern professional-grade photographic equipment, and with (b) sufficient resolution to be objectively verified via a Structural Similarity Index by specialized software for pattern recognition. Three participants, expert in distant ‘mind-matter interaction’ techniques, completed a total of 49 trials. In 6 out of 49 trials (12.2%), the Structural Similarity Index of the ‘target’ image, chosen by the participant for the distant mental influence trial on the camera’s sensor, was greater than that obtained when the target was different. These preliminary results suggest the possibility of using modern cameras to study the putative effects of distant ‘mind-matter’ interactions
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