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Phenolic resin pyrolytic carbons were obtained by catalytic pyrolysis of phenolic resin at 500 °C, 600 °C, 700 °C, and 800 °C for 3 h in an argon atmosphere using copper nitrate as a catalyst precursor. The effects of copper salts on the pyrolysis process of phenolic resin as well as the structural evolution and oxidation resistance of phenolic resin pyrolytic carbons were studied. The results showed that copper oxide (CuO) generated from the thermal decomposition of copper nitrate was reduced to copper (Cu) by the gas generated from the thermal decomposition of the phenolic resin. Carbon nanofibers with tapered structures were synthesized by Cu catalysis of pyrolysis gas at 500–800 °C. The catalytic pyrolysis of phenolic resin with Cu increased the graphitization degree and reduced the pore volume of the phenolic resin pyrolytic carbons. The combined action improved the oxidation resistance of phenolic resin pyrolytic carbons. [ABSTRACT FROM AUTHOR]

Eu3+ ion doped cubic Na5Lu9F32 single crystals with high quality were synthesized by a modified Bridgman method by using a high 70–90 °C/cm temperature gradient for cross solid-liquid interface. The optical spectroscopic investigations of the obtained single crystal were reported for the absorption, excitation and emission. The experimental results show that a strong red emission at 609 nm attributing to the 5D0→7F2 transition of Eu3+ doped Na5Lu9F32 single crystals can be obtained under the excitation of 394 nm light and reach the maximum when the Eu3+ doping concentration is 4mol% in present research. The local covalent is enhanced and symmetry is reduced with the increase of Eu3+ concentrations inferring from the strength parameters Ω2 and Ω4 calculated by their measured emission spectra. The CIE chromaticity coordinates of the 4mol% Eu3+ doped Na5Lu9F32 single crystals are calculated as (x=0.626, y=0.3736), which are close to the NTSC standard values for red (x=0.67, y=0.33). The experimental results reveal that the single crystal can be used as potential red phosphors under near ultraviolet (NUV) light excitation. [ABSTRACT FROM AUTHOR]