29 research outputs found

    Report of the ultraviolet and visible sensors panel

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    In order to meet the science objectives of the Astrotech 21 mission set the Ultraviolet (UV) and Visible Sensors Panel made a number of recommendations. In the UV wavelength range of 0.01 to 0.3 micro-m the focus is on the need for large format high quantum efficiency, radiation hard 'solar-blind' detectors. Options recommended for support include Si and non-Si charge coupled devices (CCDs) as well as photocathodes with improved microchannel plate readouts. For the 0.3 to 0.9 micro-m range, it was felt that Si CCDs offer the best option for high quantum efficiencies at these wavelengths. In the 0.9 to 2.5 micro-m the panel recommended support for the investigation of monolithic arrays. Finally, the panel noted that the implementation of very large arrays will require new data transmission, data recording, and data handling technologies

    Impulsivity and approach tendencies towards cigarette stimuli: Implications for cigarette smoking and cessation behaviors among youth

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    Impulsivity is associated with smoking, difficulties quitting smoking, and approach tendencies toward cigarette stimuli among adolescents. We examined the effects of impulsivity on (a) the association between approach tendencies and adolescents’ smoking status and (b) the effectiveness of Cognitive Bias Modification (CBM), a smoking cessation intervention focused on changing approach tendencies, among adolescent smokers. We conducted a secondary analysis of evidence from 2 previous published studies: Study 1: a cross-sectional study comparing impulsivity and approach tendencies between adolescent smokers (n = 67) and nonsmokers (n = 58); Study 2: a treatment study that randomized 60 adolescent smokers to receive either CBM or sham training. Impulsivity was measured using the Barratt Impulsiveness Scale (BIS) and the Experiential Discounting Task (EDT). We found higher impulsivity, as determined by the BIS but not the EDT, increased adolescents’ odds of being smokers. We observed that the interaction between EDT and approach tendencies also significantly predicted smoking status, however post hoc comparisons were not significant. Adolescents with higher BIS scores receiving CBM had increased odds of being abstinent at the end of treatment, but we found no association between EDT and treatment outcome. Our findings suggest that approach-bias modification (a form of CBM) may be more effective in impulsive adolescent smokers. Differences in findings for BIS and EDT highlight the complexity of the construct of impulsivity. Future studies with larger samples are needed to further disentangle the effects of different aspects of impulsivity on smoking behaviors and cessation outcomes among youth

    Flexible Wire‐Shaped Perovskite Photodetector via Joule Heating for Improved Crystallization and Performance

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    Organolead triiodide perovskite (CH3NH3PbI3) is used extensively as the absorber material for both solar cells and photodetectors; however, the reported photodetectors are all planar and flexible planar devices. To the best of knowledge the first flexible wire-shaped perovskite photodetector is reported. The performance of the wire-shaped perovskite photodetector on carbon nanotube yarn (CNY) critically depends on the surface geometry and annealing conditions. The use of joule heating method for uniform control of temperature on CNY surface results in smooth perovskite crystalline films, which are used to produce self-powering photodetectors with strong responsivity (10.2 A W−1), detectivity (1.76 × 1011 J), and Ilight/Idark (45). This development displays the role of joule heating in the annealing process and demonstrates a cheap, repeatable method for the fabrication of self-powered perovskite photodetectors

    Design of a CMOS Image Sensor

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