RESUMO
The Eu³âº, Bi³âº ions co-doped Y2O3 phosphor has been synthesized by the conventional solid-state reaction method, and its photoluminescence (PL) spectra are investigated for application in white light emitting diode (LED). The Eu³âº, Bi³âº ions co-doped Y2O3 phosphor showed a characteristic emissions with greenish blue and red color upon the near-UV light in the range of 310-360 nm, originating from ³P1 --> ¹S0 transition of Bi³âº and 5D0 --> 7F(J) transition of Eu³âº, respectively. As 613-nm emission of Eu³âº ions is monitored, excitation spectrum consists of two broad peaks near 230 nm and 330 nm, ascribed to the Eu³âº-O²- charge transfer band (CTB) and the transition from the ground state to the excited states of Bi³âº ions, respectively. It implies that the energy transfer from Bi³âº ions to E³âº ions occur and the phosphor's color may be controlled by adjusting the concentrations of Eu³âº ions and Bi³âºons in Y202O3The availability of this strategy is demonstrated in this work, and white light can be realized with superior chromaticity coordinates of (x = 0.337, y = 0.328) and a CCT of 5284 K for Y202O3% Eu3+³âº0.1% Bi3+³âºThus, it will be a promising candidate for the ultraviolet excitation white light emitting diode (LED).
RESUMO
Leaf sheath color plays an important role as a marker for rice genetic improvement. A recombinant inbred line (RIL) population consisting of 220 individuals was developed from a cross between an Oryza sativa subsp. indica variety, IRBB60, and an Oryza sativa subsp. japonica variety, 9407. Within the RIL population, a line, RI51, was found to have purple leaf sheath (PSH). To map the gene governing PSH, RI51 was crossed with 9407 green leaf sheath (GSH) to develop an F2 segregating population. The distribution of F2 plants with PSH and GSH fitted a segregation ratio of 3:1, indicating that the PSH was controlled by a major dominant gene. The gene locus for PSH, tentatively designated as PSH1(t), was identified by surveying two bulks made of the respective 40 individuals with PSH and GSH with SSR markers covering the entire rice genome. The survey indicated that the PSH1(t) region was located on chromosome 1. Further confirmation was made using a large random sample of 360 individuals from the same F2 population and the PSH1(t) locus was then mapped on chromosome 1 between SSR markers RM3475 and RM7202 with genetic distances of 2.0 and 1.1 cM, respectively. For fine mapping of PSH1(t), a large F(2:3) segregating population with 3300 individuals from the seven heterozygous F2 plants in the RM3475-RM7202 region was constructed. Analysis of recombinants in the PSH1(t) region anchored the gene locus to an interval of 23.5 kb flanked by the left marker L03 and the right marker L05. Sequence analysis of this fragment predicted six open reading frames encoding a putative trans-sialidase, a putative Plastidic ATP/ADP-transporter, and four unknown proteins. The detailed genetic and physical maps of the PSH1(t) locus will be very useful in molecular cloning of the PSH1(t) gene.
