5,476 research outputs found

    Solar cell radiation handbook

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    The handbook to predict the degradation of solar cell electrical performance in any given space radiation environment is presented. Solar cell theory, cell manufacturing and how they are modeled mathematically are described. The interaction of energetic charged particles radiation with solar cells is discussed and the concept of 1 MeV equivalent electron fluence is introduced. The space radiation environment is described and methods of calculating equivalent fluences for the space environment are developed. A computer program was written to perform the equivalent fluence calculations and a FORTRAN listing of the program is included. Data detailing the degradation of solar cell electrical parameters as a function of 1 MeV electron fluence are presented

    Manipulating ionization path in a Stark map: Stringent schemes for the selective field ionization in highly excited Rb Rydberg atoms

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    We have developed a quite stringent method in selectivity to ionize the low angular- momentum (\ell) states which lie below and above the adjacent manifold in highly excited Rb Rydberg atoms. The method fully exploits the pulsed field-ionization characteristics of the manifold states in high slew-rate regime: Specifically the low \ell state below (above) the adjacent manifold is firstly transferred to the lowest (highest) state in the manifold via the adiabatic transition at the first avoided crossing in low slew-rate regime, and then the atoms are driven to a high electric field for ionization in high slew-rate regime. These extreme states of the manifold are ionized at quite different fields due to the tunneling process, resulting in thus the stringent selectivity. Two manipulation schemes to realize this method actually are demonstrated here experimentally.Comment: 10 pages, 4 figure

    Systematic observation of tunneling field-ionization in highly excited Rb Rydberg atoms

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    Pulsed field ionization of high-nn (90 n\leq n \leq 150) manifold states in Rb Rydberg atoms has been investigated in high slew-rate regime. Two peaks in the field ionization spectra were systematically observed for the investigated nn region, where the field values at the lower peak do not almost depend on the excitation energy in the manifold, while those at the higher peak increase with increasing excitation energy. The fraction of the higher peak component to the total ionization signals increases with increasing nn, exceeding 80% at nn = 147. Characteristic behavior of the peak component and the comparison with theoretical predictions indicate that the higher peak component is due to the tunneling process. The obtained results show for the first time that the tunneling process plays increasingly the dominant role at such highly excited nonhydrogenic Rydberg atoms.Comment: 8 pages, 5 figure

    Poor development of transmitting tissue in tetraploid grape pistils causing inhibition of pollen tube growth

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    Anatomical investigations were carried out to study the cause of poor berry set in tetraploid grape cultivars, Using 6 diploid and 6 tetraploid grape cultivars, the development of the transmitting tissue (TT) and pollen tube growth in their pistils were examined. The rates of berry set and seed number per berry were also investigated. TT was found to be cylindrical in the style and elliptic-conical in the ovaries. In the middle part of the ovary, the TT had developed along the inner surface of each septum projecting from both sides of the ovary wall. In the middle style, the TT diameter of tetraploid cultivars was larger than in diploid cultivars, However, TT development in the septum was markedly poorer in most of the tetraploid cultivars examined except for cv, Fujiminori where a sufficient number of seeded berries developed on the clusters. Most pollen tubes penetrating into the ovary tissue were inhibited to grow further in tetraploid cultivars except for cv, Fujiminori, These findings suggest that the poor set of normally seeded berries in most tetraploid grapes may be due to poor development of TT in the septum, which severely inhibits pollen tube penetration into the micropyle.
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