Search

A series of barium pyrophosphate Ba2P2O7 (BPO) phosphors doped with Ce3+ or Tb3+ ions is synthesized via a co-precipitation method under reducing atmosphere. The phase structures, photoluminescence (PL) properties, and thermal stabilities of the samples are characterized by using powder x-ray diffraction (PXRD) and PL spectra. The emission colors of samples can be tuned from blue (0.1544, 0.0310) to green (0.2302, 0.4229) by changing the doping concentrations of Tb3+ under ultraviolet excitation. The energy transfer mechanism between Ce3+ and Tb3+ in the BPO is dipole–dipole interaction with a critical distance of 25.86 Ĺ and an energy transfer efficiency of about 85%, which are determined through the PL spectrum and the decay curve. Moreover, the Ce3+/Tb3+ co-doped sample has good thermal stability for temperature quenching, and the emission intensity at 423 K is maintained at 95% measured at 298 K. The above results show that the BPO:Ce3+, Tb3+ can serve as a promising candidate of green emitting phosphor for solid-state lighting. [ABSTRACT FROM AUTHOR]

Uniform orange-to-red spherical phosphors of Sr2 P2 O7: Ce3+, Mn2+ have been synthesized by the co-precipitation method and characterized by X-ray powder diffraction, scanning electron microscopy, and photoluminescence spectroscopy. The results indicate that the morphology, size, and photoluminescence properties of Sr2 P2 O7: Ce3+, Mn2+ phosphors can be effectively controlled by the reaction and the sintering temperatures. Energy transfer from Ce3+ to Mn2+ in Sr2 P2 O7 phosphor was observed from photoluminescence spectra of Sr2 P2 O7: Ce3+, Sr2 P2 O7: Mn2+, and Sr2 P2 O7: Ce3+, Mn2+. Moreover, based on a self-assembly process, a possible formation mechanism for the spherical phosphors is proposed. The uniform phosphor spheres obtained in this work exhibit great potential for high-resolution display devices such as light emitting diodes. [ABSTRACT FROM AUTHOR]

In the present paper, broad bean rust, fusarium rhizome rot, broad bean zonate spot, yellow leaf curl virus and normal leaves were studied using Fourier transform infrared spectroscopy combined with chemometrics. The results show that the spectra of samples were similar, only with minor differences in absorption intensity of several peaks. Second derivative analyses show that the significant difference of all samples was in the range of 1200-700 cm(-1). The data in the range of 1 200-700 cm(-1) were selected to evaluate correlation coefficients, hierarchical cluster analysis (HCA) and principal component analysis (PCA). Results showed that the correlation coefficients are larger than 0.928 not only between the healthy leaves, but also between the same diseased leaves. The values between healthy and diseased leaves, and among diseased leaves, are all declined. HCA and PCA yielded about 73.3% and 82.2% accuracy, respectively. This study demonstrated that FTIR techniques might be used to detect crop diseases.

In the present paper, the contents of 8 elements in brown rice of 789 accessions core collection for rice landrace from 16 prefectures of five rice regions in Yunnan province were determined by ICP-AES technique. The method proves to be simple, rapid, highly sensitive and accurate, and can be used to determine many elements at the same time. Its recovery ratio obtained by standard addition method ranged from 97.1% to 110.2%, and its RSD was from 0.7% to 4.4%. The analytical results showed that the elemental concentrations (mg x kg(-1) ) in brown rice are in turn of P(3 834.83 +/- 486.49) > K(2 567.72 +/- 336.74) > Mg (2 567.72 +/- 336.74) > Ca (153.67 +/- 55.90) > Zn( 33.35 +/- 13.65) > Fe(32.08 +/- 25.51) > Cu (14.22 +/- 11.85) > Mn(13.58 +/- 3.22). The highest P content is in brown rice from the northwest Yunnan with the rich nonferrous metals and most abundance of biodiversity in the world, the highest Ca, Mg, Fe and Zn concentrations are in brown rice from the middle Yunnan with early cambrian fauna and phosphorite enrichment, and the highest Cu and Mn contents are in brown rice from the southwest Yunnan with the prominent crop diversity. The distributing zones with the highest P and K, middle Ca, Mg and Mn and lowest Fe and Zn in Yunnan are the enrichment zone of minal resources and largest biodiversity. As far as we know, this is the first report that the zonal characterstics of mineral elemental concentractions in brown rice are associated with a lot of factors, such as biodiversity center, enrichment zone of minal resources, origin of life, mountain ranges and rivers and so on, and further it was deduced that the asymmetry of distribution for mineral elements and its reciprocity of mountain ranges and rivers are the key of origin of life. The above results provided reliable data and theory bases for the malnourished Fe and Zn and Ca for 4 billion people in the world, origin of life, the genetic breeding and production of functional rice.

In the present paper, the contents of 18 mineral elements in milled and brown rice of 55 accessions elite cultivars as well as corresponding soils were determined by ICP-AES technique. The method proves to be simple, rapid, highly sensitive and accurate, and can be used to determine many elements at the same time, its recovery ratio obtained by standard addition method ranged between 93.1% and 110.2%, and its RSD was from 0.8% to 5.1%. The analytical results showed that 18 mineral elements (S, Mo, Ba, Ni, Fe, Cr, Na, Al, Cu, P, Sn, Zn, B, Mn, Mg, Ca, Sr and K) are the important active compositions of functional rice, and their mean contents in milled rice are in the order of P>K>S>Mg>Ca>Zn>Na>Al>Mn>Fe>Cu>B >Mo>Ni>Sn>Cr>Ba>Sr, in brown rice in the order of P>K>Mg>S>Ca>Zn>Mn>Al>Na>Fe>Cu>B>Mo>Sn> Ni>Cr>Ba>Sr, but in soil in the order of Fe>Al>Ca>K>Mg>P>S>Mn>B>Na>Ba>Zn>Cr>Cu>Ni>Sn>Mo> Sr; 16 mineral elements in milled and brown rice (except for S and P) are clearly lower than that in soils. The correlation of 8 microelements (Mo, Ni, Cr, Sr, Mn, Zn, Cu and Na) in milled and brown rice is closer than that of 6 macroelements (P, K, Mg, Ca, S and Al). There are rich Fe, Al and Ca in Yunnan soils, but 4 elements (P, K, Mg and S) are in high priority in milled and brown rice; The milled rice used for the staple is easier to place a premium on chronics than brown rice. The above results provided reliable data and theory bases for genetic breeding and production of functional rice, and for further solving the chronics and the malnourished problems with insufficient Fe, Zn and Ca for 4 billion people in the world.

In the present paper, the contents of 17 mineral elements (S, Mo, Ni, Fe, Cr, Na, Al, Cu, P, Sn, Zn, B, Mn, Mg, Ca, Sr and K) in brown rice of 264 plant lines in near-isogenic lines (NILs) population and parents for Japonica rice were determined by ICP-AES technique. The method proved to be simple, rapid, highly sensitive and accurate, and can be used to determine many elements at the same time. Its recovery ratio obtained by standard addition method ranged between 92.3% and 110.27%, and its RSD was lower than 6%. The analytical results showed that NILs for various mineral elements based on the BC5F5 population consisting of 261 lines were developed from a cross between NIL (BC4F5) and Towada. To our knowledge, this is the first report on that near-isogenic lines NIL(BC4F5) with the important value for high mineral elements associated with cold tolerance at booting stage have been bred. The results of the determination show that the brown rice is rich in eleven elements such as P, K, Mg, S, Ca, Zn, Mn, Na, Fe, Cu and Al necessary to human health. There is smaller variation of 5 macroelements (11.15%-16.45%) but larger variation of 12 microelements (16.57%-94.96%) in brown rice from populations. There is significant correlation among 95 from 136 pairs in 17 elements, moreover, especially the correlation (0.531**-0.921**) among 15 pairs of six micro-elements (Mo, Ni, Al, Sn, Cr and Sr) associated with the active components of functional rice is relatively higher than that of 10 pairs (0.175**-0.867**) of 5 macroelements (P, K, Ca, Mg and S), revealing the importance of microelements to catalysing and synthesizing the active components of functional rice. The above results provided reliable data and theory bases for gene location and cloning of controlling elements contents in brown rice, and further revealed the molecular and physiological mechanism of the relation between mineral elements in brown rice and cold tolerance at booting stage in japonica rice from Yunnan Province of China.