Влияние отжига в газообразном цинке на люминесценцию в видимом и среднем ИК диапазонах ZnSe : Fe-=SUP=-2+-=/SUP=-

The study results of the effect of annealing in a zinc vapor atmosphere on the defect and impurity composition of iron diffusion-doped ZnSe:Te plates on the characteristics of cathodoluminescence (CL) in the IR range are described. The formation of precipitates at the boundaries of twin faults was found. It is shown that in structures with a surface iron concentration of more than 1 at%, a significant increase in the CL intensity in the IR range is observed as a result of annealing in a zinc vapor atmosphere. A partial recovery of interband luminescence in regions with a high iron concentration as a result of annealing was found.

Исследование влияния легирования железом на люминесценцию монокристаллов селенида цинка

The effect of doping with iron (thermal diffusion from a surface) on the luminescence of zinc-selenide single crystals in the wavelength range 0.44–0.72 μm and on the spatial distribution of luminescence centers are studied. By means of two-photon confocal microscopy, planar and volume maps of edge (exciton) and impurity–defect luminescence in the above-indicated spectral range are obtained for both doped and undoped crystals. It is shown that crystal regions containing a high iron concentration exhibit low-intensity luminescence in this range. It is found that, in the process of diffusion, several types of impurity–defect centers distributed in a complex way within the crystal bulk are formed. The nature of these centers is discussed.

Genetic parameters and combined selection for phosphorus, phytate, iron, and zinc in Mesoamerican common bean lines

ABSTRACT The development of common bean cultivars that contain satisfactory minerals and phytate concentrations for the different nutritional requirements of consumers is a new strategy of breeding programs. This work aimed to obtain estimates of genetic parameters for the concentrations of phosphorus, phytate, iron, and zinc in a recombinant inbred line (RIL) population of Mesoamerican common bean, to study the correlations between these traits, and to select common bean lines for the biofortification program and for diets that require the decrease in the intake of these minerals. The RIL were obtained from the cross between BRS Esteio and SCS 205 Riqueza. Genetic variability and transgressive segregation were detected for all traits evaluated. Heritability estimates for the concentrations of phosphorus, phytate, iron, and zinc ranged from intermediate (h2: 30.31%) to high (h2: 98.68%) magnitude, and quantitative inheritance was observed. The phosphorus concentration showed an intermediate correlation estimate with iron (r = 0.4157) and zinc (r = 0.5693) concentrations. Cultivar BRS Expedito and line L 56-17 have a low phytate concentration (≤ 1.29%) and a high iron concentration (≥ 95 mg kg-1 of dry matter - DM), and will be selected by the common bean biofortification program. Lines L 59-17, L 31-17, and L 26-17 and cultivars IPR Siriri and BRS Valente have a high phytate concentration (≥ 2.57%) and a low zinc concentration (≤ 26 mg kg-1 DM) and will be selected for diets that aim at using the beneficial properties of phytate and reducing the zinc intake.

Seasonal variation and speciation of dissolved iron in an artificial surface water body

The aquatic chemistry of iron is an important issue since iron is a micronutrient for the growth of phytoplankton. Its concentration in surface waters involves many environmental aspects, from the quality of a particular water to the control of atmospheric carbon dioxide. Dissolved iron can exist in water as ferrous and ferric iron, and the equilibrium between these two forms, as well as the precipitation and solubilization of iron, depends on many natural and anthropic factors. We studied the variation for an year of Fe(II) and total iron concentration into Poarta Alba - Midia Navodari Canal, an artificial surface water which connects Danube River with Black Sea. The results indicate a high iron concentration in surface water and a seasonal variation of iron concentration and speciation, which can be correlated with the oxidable matter content.

Genetic control of iron concentration in Mesoamerican and Andean common bean seeds

The objective of this work was to evaluate the main differences in the genetic control of the iron concentration in Mesoamerican and Andean common bean seeds, in early generations, and to select recombinants with a high iron concentration in the seeds. F1, F1 reciprocal, F2, F2 reciprocal, and backcross (BC11 and BC12) generations were produced by crosses between Mesoamerican (CNFP 10104 x CHC 01-175) and Andean (Cal 96 x Hooter) inbred lines. The expression of significant maternal effect was observed for the Mesoamerican gene pool. Iron concentration was higher in the seed coat of Mesoamerican common bean seeds (54.61 to 67.92%) and in the embryo of Andean common bean seeds (69.40 to 73.44%). High broad-sense heritability was obtained for iron concentration in Mesoamerican and Andean common bean seeds. Gains with the selection of higher magnitude, from 20.39 to 24.58%, are expected in Mesoamerican common bean seeds. Iron concentration in common bean seeds showed a continuous distribution in F2, which is characteristic of quantitative inheritance in Mesoamerican and Andean common bean seeds. Recombinants with high iron concentration in seeds can be selected in both Mesoamerican and Andean common bean hybrids.