Nuclear Shadowing in a Parton Recombination Model

Deep inelastic structure functions $F_2^A(x)$ are investigated in a $Q^2$ rescaling model with parton recombination effects. We find that the model can explain experimentally measured $F_2^A(x)$ structure functions reasonably well in the wide Bjorken$-x$ range ($0.005<x<0.8$). In the very small $x$ region ($x<0.02$), recombination results are very sensitive to input sea-quark and gluon distributions.Comment: preprint MKPH-T-93-04, IU/NTC 92-20, 25 pages, TEX file (without Figs. 1-14)., (address after April 1: Saga U., Japan

Investigating the effect of N‐doping on carbon quantum dots structure, optical properties and metal ion screening

Carbon quantum dots (CQDs) derived from biomass, a suggested green approach for nanomaterial synthesis, often possess poor optical properties and have low photoluminescence quantum yield (PLQY). This study employed an environmentally friendly, cost-effective, continuous hydrothermal flow synthesis (CHFS) process to synthesise efficient nitrogen-doped carbon quantum dots (N-CQDs) from biomass precursors (glucose in the presence of ammonia). The concentrations of ammonia, as nitrogen dopant precursor, were varied to optimise the optical properties of CQDs. Optimised N-CQDs showed significant enhancement in fluorescence emission properties with a PLQY of 9.6% compared to pure glucose derived-CQDs (g-CQDs) without nitrogen doping which have PLQY of less than 1%. With stability over a pH range of pH 2 to pH 11, the N-CQDs showed excellent sensitivity as a nano-sensor for the highly toxic highly-pollutant chromium (VI), where efficient photoluminescence (PL) quenching was observed. The optimised nitrogen-doping process demonstrated effective and efficient tuning of the overall electronic structure of the N-CQDs resulting in enhanced optical properties and performance as a nano-sensor

Solar-t : Terahertz Photometers To Observe Solar Flare Emission On Stratospheric Balloon Flights

A new solar flare spectral component has been found with intensities increasing for larger sub-THz frequencies, spectrally separated from the well known microwaves component, bringing challenging constraints for interpretation. Higher THz frequencies observations are needed to understand the nature of the mechanisms occurring in flares. A twofrequency THz photometer system was developed to observe outside the terrestrial atmosphere on stratospheric balloons or satellites, or at exceptionally transparent ground stations. 76 mm diameter telescopes were designed to observe the whole solar disk detecting small relative changes in input temperature caused by flares at localized positions at 3 and 7 THz. Golay cell detectors are preceded by low-pass filters to suppress visible and near IR radiation, band-pass filters, and choppers. It can detect temperature variations smaller than 1 K with time resolution of a fraction of a second, corresponding to small burst intensities. The telescopes are being assembled in a thermal controlled box to which a data conditioning and acquisition unit is coupled. While all observations are stored on board, a telemetry system will forward solar activity compact data to the ground station. The experiment is planned to fly on board of long-duration stratospheric balloon flights some time in 2013-2015. One will be coupled to the GRIPS gamma-ray experiment in cooperation with University of California, Berkeley, USA. One engineering flight will be flown in the USA, and a 2 weeks flight is planned over Antarctica in southern hemisphere summer. Another long duration stratospheric balloon flight over Russia (one week) is planned in cooperation with the Lebedev Physics Institute, Moscow, in northern hemisphere summer. © 2012 SPIE.8442The Society of Photo-Optical Instrumentation Engineers (SPIE)Erickson, E.F., SOFIA: The next generation airborne observatory (1985) Space Sci. Rev., 84, pp. 91-100Poglitsch, A., The photodetector array camera and spectrometer (PACS) on the Herschel space observatory (2010) Astron. Astrophys., 518 (L2), pp. 1-12Degiacomi, C.G., Kneubühl, F.K., Huguenin, D., Far-infrared solar imaging from a balloon-borne platform (1985) Astrophys. J., 298, pp. 918-933Lawrence, J.S., Infrared and submillimeter atmospheric characteristics of high Antarctic plateau sites (2004) Publ. Astron Soc. Pacific, 116, pp. 482-492Marcon, R., Terahertz photometer to observe solar flares in continuum (2012) J. Infrared, Millimeter and Terahertz Waves, 33, pp. 192-205Marcon, R., Kaufmann, P., (2011) Método Para Maximizar Ganho Na Detecção Simultânea de Radiação de Fontes Pequenas em Campo Extenso de Visão, , Brazil Patent Application, Universidade Estadual de Campinas and Instituto Presbiteriano Mackenzie, March 30Phillips, T.G., (1988) Techniques of Submillimeter Astronomy, in Millimetre and Submillimetre Astronomy, pp. 1-25. , (Ed. by R.D. Wolstencroft and W.B. Burton), Lectures at Summer School, Stirling, Scotland, June 21-27, 1987 (Kluwer Academic Publishers, Dordrecht, NL)http://www.tydexoptics.com/pdf/Golay_cell.pdfShih, A.Y., The gamma-ray imager/polarimeter for solar flares (GRIPS) (2008) American Geophysical Union, , Fall Meeting, abstract SM11B-1602Texereau, J., (1984) How to Make A Telescope, pp. 139-175. , 2th English Edition (Wilmann-Bell Inc. Richmond, VA)Bortolucci, E.C., THz band-pass resonant metal mesh filters for a space solar photometry experiment (2012) VII SEMINATEC 2012 Workshop, , FEI, São Bernardo do Campo, SP, Brazil, 12-13 April(2012), http://www.tydexoptics.com/pdf/THz_Low_Pass_Filter.pdf(2012), http://www.eopc.com/choppers.html(2012), http://www.tydexoptics.com/new_products1/digital_golaycellhttp://www.satrunner.com/en/iridium-9602-sbd-modem.htmlhttp://www.wcclp.com/SBD.as