The TiO_(2) ceramics doped with nano CuO were fabricated by the conventional solid-state reaction method.The crystal structure,microstructure,microwave dielectric properties and lattice vibrations of TiO_(2) ceramics ...The TiO_(2) ceramics doped with nano CuO were fabricated by the conventional solid-state reaction method.The crystal structure,microstructure,microwave dielectric properties and lattice vibrations of TiO_(2) ceramics doped with nano CuO have been investi-gated.Nano CuO with higher sintering capability worked as flux former and effectively improved the sintering process of TiO_(2) ceramics.The microwave dielectric properties of TiO_(2) doped with nano CuO were much better than that doped with micron CuO at the same doping content.Raman spectra showed that the full width at half maximum of E_(g) mode of TiO_(2) doped with micron CuO was larger than nano CuO doped ones,which indicated a poor crystalline and a short phonon lifetime.TiO_(2) doped with 1wt.% nano CuO,sintered at 950℃ for 2h had compact and homogeneous microstructure and possessed the following dielectric properties:ε_(r)=106,Q×f=24808,τf=371ppm/℃.展开更多
The 96 h acute toxic effects of nano-CuO (N-CuO), micro-CuO (M-CuO) and 2+ on Chlorella sp. were investigated in this paper. The results showed that toxicities decreased in an order of Cu2+>N-CuO>M-CuO. The 96 h...The 96 h acute toxic effects of nano-CuO (N-CuO), micro-CuO (M-CuO) and 2+ on Chlorella sp. were investigated in this paper. The results showed that toxicities decreased in an order of Cu2+>N-CuO>M-CuO. The 96 h EC50 of Cu2+ on Chlorella sp. was 1.06 mg /L, and of N-CuO it was 74.61 mg /L, while no pronounced toxicity was observed when the concentration of M-CuO was lower than 160 mg/L. Further experiments were carried out in order to study the toxicity mechanism of nano-CuO on Chlorella sp.. The results of Cu2+ release from N-CuO showed less than 0.2 mg/L Cu2+ were released, so the release of Cu2+ was not responsible for the toxicity. Further experiments showed N-CuO inhibited formation of Chlorophyll A. Content of Chlorophyll A in the control group was 4.75 mg/108 cells, while it declined to 2.89 mg/108 cells for 160 mg/L N-CuO after 96 h, which indicated that N-CuO could inhibit photosynthesis of Chlorella sp.. Moreover, N-CuO condensed with algal cells. It affected the activity of SOD and POD, indicating that N-CuO could cause oxidant stress to Chlorella sp.. These may be the toxicity mechanism.展开更多
Nano-scale copper oxide with various morphologies is synthesized via the thermal oxide method and growth in a 5 wt% NaCl solution of spray fog environment. The nano-scale copper oxide is grown on copper metal sheets v...Nano-scale copper oxide with various morphologies is synthesized via the thermal oxide method and growth in a 5 wt% NaCl solution of spray fog environment. The nano-scale copper oxide is grown on copper metal sheets via the thermal oxide method at 650℃ for 60 minutes. Nano-scale copper oxide grains and nanowires are induced on copper metal sheets then placed in 5 wt% NaCl solution of salt spray fog environment. Significant changes in particle size and mor-phology are observed with increasing salt spray fog treatement time. The morphology of nano-scale copper oxide varies from nanograins to nanowires, Ctahedron, and icositetrahedron. The morphologies and structures of the obtained nano-scale copper oxide are investigated by scanning electron microscopy and energy-dispersive spectroscopy. Possible growth mechanisms are discussed.展开更多
Nano-CuO was prepared by heating nano-Cu2(OH)2CO3 precursors in different calcination temperatures. The precursor was synthesized from water-alcohol mixed solution of Cu(Ac)2 using mixed solution of NaOH and Na2CO3 as...Nano-CuO was prepared by heating nano-Cu2(OH)2CO3 precursors in different calcination temperatures. The precursor was synthesized from water-alcohol mixed solution of Cu(Ac)2 using mixed solution of NaOH and Na2CO3 as precipitants. XRD, FT-IR, TEM, TG-DTA and surface area measurement techniques were used to investigate the properties of the CuO powder. The results show that the spherical, well dispersed nano-CuO powder with the average size of 15 nm and higher catalytic activity for H2O2 decomposition was obtained at 300 ℃. With the increasing of calcination temperature, crystal of CuO grows up, agglomeration of the powder becomes heavier and catalytic activity decreases. FT-IR patterns revealed that the vibration fine structure of Cu-O bond in nano-CuO powder disappears and main absorption is red-shifted with the average size of nano-CuO reducing.展开更多
基金The authors acknowledge the financial support of the Science and Technology projects of Guangdong Province(2011A091103002).
文摘The TiO_(2) ceramics doped with nano CuO were fabricated by the conventional solid-state reaction method.The crystal structure,microstructure,microwave dielectric properties and lattice vibrations of TiO_(2) ceramics doped with nano CuO have been investi-gated.Nano CuO with higher sintering capability worked as flux former and effectively improved the sintering process of TiO_(2) ceramics.The microwave dielectric properties of TiO_(2) doped with nano CuO were much better than that doped with micron CuO at the same doping content.Raman spectra showed that the full width at half maximum of E_(g) mode of TiO_(2) doped with micron CuO was larger than nano CuO doped ones,which indicated a poor crystalline and a short phonon lifetime.TiO_(2) doped with 1wt.% nano CuO,sintered at 950℃ for 2h had compact and homogeneous microstructure and possessed the following dielectric properties:ε_(r)=106,Q×f=24808,τf=371ppm/℃.
文摘The 96 h acute toxic effects of nano-CuO (N-CuO), micro-CuO (M-CuO) and 2+ on Chlorella sp. were investigated in this paper. The results showed that toxicities decreased in an order of Cu2+>N-CuO>M-CuO. The 96 h EC50 of Cu2+ on Chlorella sp. was 1.06 mg /L, and of N-CuO it was 74.61 mg /L, while no pronounced toxicity was observed when the concentration of M-CuO was lower than 160 mg/L. Further experiments were carried out in order to study the toxicity mechanism of nano-CuO on Chlorella sp.. The results of Cu2+ release from N-CuO showed less than 0.2 mg/L Cu2+ were released, so the release of Cu2+ was not responsible for the toxicity. Further experiments showed N-CuO inhibited formation of Chlorophyll A. Content of Chlorophyll A in the control group was 4.75 mg/108 cells, while it declined to 2.89 mg/108 cells for 160 mg/L N-CuO after 96 h, which indicated that N-CuO could inhibit photosynthesis of Chlorella sp.. Moreover, N-CuO condensed with algal cells. It affected the activity of SOD and POD, indicating that N-CuO could cause oxidant stress to Chlorella sp.. These may be the toxicity mechanism.
文摘Nano-scale copper oxide with various morphologies is synthesized via the thermal oxide method and growth in a 5 wt% NaCl solution of spray fog environment. The nano-scale copper oxide is grown on copper metal sheets via the thermal oxide method at 650℃ for 60 minutes. Nano-scale copper oxide grains and nanowires are induced on copper metal sheets then placed in 5 wt% NaCl solution of salt spray fog environment. Significant changes in particle size and mor-phology are observed with increasing salt spray fog treatement time. The morphology of nano-scale copper oxide varies from nanograins to nanowires, Ctahedron, and icositetrahedron. The morphologies and structures of the obtained nano-scale copper oxide are investigated by scanning electron microscopy and energy-dispersive spectroscopy. Possible growth mechanisms are discussed.
文摘Nano-CuO was prepared by heating nano-Cu2(OH)2CO3 precursors in different calcination temperatures. The precursor was synthesized from water-alcohol mixed solution of Cu(Ac)2 using mixed solution of NaOH and Na2CO3 as precipitants. XRD, FT-IR, TEM, TG-DTA and surface area measurement techniques were used to investigate the properties of the CuO powder. The results show that the spherical, well dispersed nano-CuO powder with the average size of 15 nm and higher catalytic activity for H2O2 decomposition was obtained at 300 ℃. With the increasing of calcination temperature, crystal of CuO grows up, agglomeration of the powder becomes heavier and catalytic activity decreases. FT-IR patterns revealed that the vibration fine structure of Cu-O bond in nano-CuO powder disappears and main absorption is red-shifted with the average size of nano-CuO reducing.
