In the recent years, extensive research work is being carried out and reported on improving the performance of catalysts for both anode and cathode of polymer electrolyte membrane fuel cell (PEMFC). The single cell performance of carbon supported Pt–WO3 electrocatalysts with various compositions (as weight percentage Pt–W 2:8, 4:6, 6:4, 2:8) as anode material was investigated in polymer electrolyte membrane fuel cell and compared to that of 10% Pt/C on the same carbon support and 10% Pt/C (commercial) electrocatalyst. The physical and morphological characterization of the optimized Pt–WO3, 10% Pt/C, 10% Pt/C (commercial) electrocatalysts were further investigated by X-ray diffraction (XRD), cyclic voltammetry, and scanning electron microscopy (SEM) with EDX, transmission electron microscopy (TEM) techniques. The performance of Pt–WO3/C (with a weight percentage of Pt–W 6:4) as anode material was better than those of other compositions of Pt–WO3/C catalyst, 10% Pt/C and 10% Pt/C (commercial). The amount of Pt was also reduced from 1.76 mg cm−2 to 1.046 mg cm−2 which exhibited higher performance in single cell tests.

Saprotrophic fungi represent an important resource for a number of fungivorous and omnivorous soil animals,but little is known about the patterns of isotopic fractionation by soil fungi.We grew five common species of saprotrophic microfungi in laboratory cultures on simple artificial substrate based on carbohydrates derived either from C3orC4 plants.Fungal cultures were kept at15,20 or 25 C. Isotopic composition of carbon(13C/12C) and nitrogen(15N/14N) in bulk fungal tissue was determined after 11,21and32days.The fractionation of carbon and nitrogen stable isotopes was species-specific, but generally did not differ in C3-andC4-based growth media.The Zygomycete Mucor plumbeus did not differ in d13C from the carbon source used,though Ascomycetes(Alternaria alternata, Cladosporium cladosporioides, Trichoderma harzianum and Ulocladium botrytis) were depleted in heavy carbon relative to the carbon source by 0.5–0.9%. Three species were significantly depleted in 15N relative to the sodium nitrate that was used as a single source of nitrogen.In all species, d15N but not d13C tended to increase with the age of fungal colonies.The effect of temperature on d15N was weak and in consistent in different species.In contrast,all fungi except T. harzianum accumulated more 13C at25 1C than at 15 1C. The overall variation in the isotopic signatures of saprotrophic fungi growing in identical conditions reached 8%0 for d15N and 2.5%0 for d13C due to species-specific differences in the isotopic fractionation and the age of individual fungal colonies.This variation should be incorporated into the interpretation of the isotopic composition of fungivorous soil animals.
doi:10.1016/j.pedobi.2009.11.001

Показано, что процесс образования, роста и коалесценции преципитатов во время охлаждения кристалла после выращивания является определяющим этапом в формировании ростовой дефектной структуры бездислокационных монокристаллов кремния. Предложена кинетическая модель распада твердых растворов примесей, с помощью которой возможно моделирование процессов преципитации во время охлаждения кристалла кремния после выращивания в температурном диапазоне 1682 ... 1403 К. // It is shown that the process of formation, growth and coalescence of precipitates at crystal cooling after growth is a controlling factor of the growth defect structure formation at dislocation-free silicon single crystal. A kinetic model of decomposition of impurity solid solutions which gives an opportunity to simulate the precipitation during the silicon crystal cooling after the growth for the temperature range 1682 ... 1403 K.