A new method of using nanometer TiO 2 as solid phase extractant coupled with ICP AES was proposed for speciation of rare earth elements. The adsorption behavior of rare earth complexes on nanometer TiO 2 was inves...A new method of using nanometer TiO 2 as solid phase extractant coupled with ICP AES was proposed for speciation of rare earth elements. The adsorption behavior of rare earth complexes on nanometer TiO 2 was investigated. Effect of pH value, contact time, elution solution and interfering ions on the recovery of the rare earth complexes were studied. A quantitative recovery (>90%) was found in the pH range of 4～9.0 for Eu citric, 4.5～9.0 for Eu oxine and Eu HIBA, and 6.5～9.0 for Eu 3+ . Eu EDTA can not be adsorbed in the pH range studied. There is large difference in the adsorption behavior on nanometer TiO 2 between rare earth element and its complexes. The possibility of application of nanometer TiO 2 on the speciation of rare earth element was explored.展开更多
Two kinds of TiO_2 nanometer thin films were prepared on stainless steel bythe reverse micellar and sol-gel methods, respectively. The calcined TiO_ 2 thin films werecharacterized by X-ray diffraction (XRD), atomic fo...Two kinds of TiO_2 nanometer thin films were prepared on stainless steel bythe reverse micellar and sol-gel methods, respectively. The calcined TiO_ 2 thin films werecharacterized by X-ray diffraction (XRD), atomic force microscopy (AFM), BET surface area and X-rayphotoelectron spectroscopy (XPS). Photocatalytic activity was evaluated by photocatalyticdecoloration of methyl orange aqueous solution. The results showed that the TiO_2 thin filmsprepared by reverse micellar method (designated as RM-TiO_2 films) showed higher photocatalyticactivity than those by sol-gel method (designated as SG-TiO_2 films). This is attributed to the factthat the former is composed of smaller monodispersed spherical particles with a size of about 15 nmand possesses higher surface areas.展开更多
The tribological properties of the semi-metallic friction materials with nano-SiC were studied by the contrast experiments. The experimental result indicates that when the nano-SiC powder substitutes the general SiC p...The tribological properties of the semi-metallic friction materials with nano-SiC were studied by the contrast experiments. The experimental result indicates that when the nano-SiC powder substitutes the general SiC powder, the friction coefficient is not obviously improved.On the contrary, the wear rate increases a little. The friction surfaces and the mixed powder were examined by a scanning electron microscope and the experimental data were analysed. The main reason, which leads to the high wear, is found.展开更多
Polyethylene terephthalate (PET) has been modified by Ag, Ti, Cu and Si ion implantation with a dose ranging from 1×1016 to 2×1017 ions/cm2 using a metal vapor vacuum arc (MEVVA) source. The electrical prope...Polyethylene terephthalate (PET) has been modified by Ag, Ti, Cu and Si ion implantation with a dose ranging from 1×1016 to 2×1017 ions/cm2 using a metal vapor vacuum arc (MEVVA) source. The electrical properties of PET have been improved by metal ion implantation. The resistivity of implanted PET decreased obviously with an increase in ion dose. The results show that the conductive behavior of a metal ion implanted sample is different from Si-implantation samples. In order to understant the mechanism of electrical conduction, the structures of implanted layer were observed in detail by XRD and TEM. The nano carbon particles were dispersed in implanted PET. The nano metallic particles were built up in metallic ion implanted layers with dose range from 1 × 1016 to 1 × 1017 ions/cm2. The nanometer metal net structure was formed in implanted layer when a dose of 2 × 1017ions/cm2 is reached. Anomalous fractal growths were observed. These surface structure changes revealed conducting mechanism evolution. It is believed that the change would result in an improvement of the conductive properties. The conducting mechanism will be changed with increasing metal ion dose.展开更多
The preparation and micwave-absorbing behavior of nanosize PSZFe magnetic particles were studied.Nanosize PSZFe magnetic particles were prepared as following:nanosize Fe particles generated by themal decomposition of ...The preparation and micwave-absorbing behavior of nanosize PSZFe magnetic particles were studied.Nanosize PSZFe magnetic particles were prepared as following:nanosize Fe particles generated by themal decomposition of Fe(CO)-5 in organic solvents were encapsulated with synthesized polysilazane(PSZ) precursor and then irradiated under ultraviolet light.PSZFe particles were characterized by using transmission election microscope(TEM),X-Ray powder diffraction(XRD) and vibrating sample magntometer(VSM),and their microwave-adsorbing properties were measured by means of a vector network analyzer.The influence of the polysilazation layer on corrosion and magnetization of PSZFe particles and the relationship between polysilazation layer and micwave-absorbing behavior of PSZFe particles were investigated.Results showed that the average diameter of PSZFe particles was 30 nm,the structure of iron in PSZFe magnetic particles was α-Fe.The formation of a PSZ layer on nanosize Fe particles enchanced the corrosion resistance of PSZFe.In addition,PSZFe particles coated with 3 wt% PSZ demonstrated high corrosion resistance and fine microwave-absorbing ability as well.The reflection loss was less than -10 dB in the range of 9^8～16 GHz,and a reflection loss value of -20 dB was detected at 13 GHz.展开更多
文摘A new method of using nanometer TiO 2 as solid phase extractant coupled with ICP AES was proposed for speciation of rare earth elements. The adsorption behavior of rare earth complexes on nanometer TiO 2 was investigated. Effect of pH value, contact time, elution solution and interfering ions on the recovery of the rare earth complexes were studied. A quantitative recovery (>90%) was found in the pH range of 4～9.0 for Eu citric, 4.5～9.0 for Eu oxine and Eu HIBA, and 6.5～9.0 for Eu 3+ . Eu EDTA can not be adsorbed in the pH range studied. There is large difference in the adsorption behavior on nanometer TiO 2 between rare earth element and its complexes. The possibility of application of nanometer TiO 2 on the speciation of rare earth element was explored.
基金This project is financially supported by the National Natural Science Foundation of China (No.s 50272049, 50072016) The Excellent Young Teachers Program of MOE, China (No. (2002)350)
文摘Two kinds of TiO_2 nanometer thin films were prepared on stainless steel bythe reverse micellar and sol-gel methods, respectively. The calcined TiO_ 2 thin films werecharacterized by X-ray diffraction (XRD), atomic force microscopy (AFM), BET surface area and X-rayphotoelectron spectroscopy (XPS). Photocatalytic activity was evaluated by photocatalyticdecoloration of methyl orange aqueous solution. The results showed that the TiO_2 thin filmsprepared by reverse micellar method (designated as RM-TiO_2 films) showed higher photocatalyticactivity than those by sol-gel method (designated as SG-TiO_2 films). This is attributed to the factthat the former is composed of smaller monodispersed spherical particles with a size of about 15 nmand possesses higher surface areas.
基金FundedbytheOpenFoundationofStateKeyLaboratoryofTribologyofTsinghuaUniversity (No .SKLT0 2 1)andtheNatureScienceFoundationofSouthChinaUniversityofTechnology (No.E5 2 94 0 )
文摘The tribological properties of the semi-metallic friction materials with nano-SiC were studied by the contrast experiments. The experimental result indicates that when the nano-SiC powder substitutes the general SiC powder, the friction coefficient is not obviously improved.On the contrary, the wear rate increases a little. The friction surfaces and the mixed powder were examined by a scanning electron microscope and the experimental data were analysed. The main reason, which leads to the high wear, is found.
基金This work was supportd by the National Natural Science Foundation of China (Grant No. 59671051) 863 Project of National High Science and Technology of China.
文摘Polyethylene terephthalate (PET) has been modified by Ag, Ti, Cu and Si ion implantation with a dose ranging from 1×1016 to 2×1017 ions/cm2 using a metal vapor vacuum arc (MEVVA) source. The electrical properties of PET have been improved by metal ion implantation. The resistivity of implanted PET decreased obviously with an increase in ion dose. The results show that the conductive behavior of a metal ion implanted sample is different from Si-implantation samples. In order to understant the mechanism of electrical conduction, the structures of implanted layer were observed in detail by XRD and TEM. The nano carbon particles were dispersed in implanted PET. The nano metallic particles were built up in metallic ion implanted layers with dose range from 1 × 1016 to 1 × 1017 ions/cm2. The nanometer metal net structure was formed in implanted layer when a dose of 2 × 1017ions/cm2 is reached. Anomalous fractal growths were observed. These surface structure changes revealed conducting mechanism evolution. It is believed that the change would result in an improvement of the conductive properties. The conducting mechanism will be changed with increasing metal ion dose.
文摘The preparation and micwave-absorbing behavior of nanosize PSZFe magnetic particles were studied.Nanosize PSZFe magnetic particles were prepared as following:nanosize Fe particles generated by themal decomposition of Fe(CO)-5 in organic solvents were encapsulated with synthesized polysilazane(PSZ) precursor and then irradiated under ultraviolet light.PSZFe particles were characterized by using transmission election microscope(TEM),X-Ray powder diffraction(XRD) and vibrating sample magntometer(VSM),and their microwave-adsorbing properties were measured by means of a vector network analyzer.The influence of the polysilazation layer on corrosion and magnetization of PSZFe particles and the relationship between polysilazation layer and micwave-absorbing behavior of PSZFe particles were investigated.Results showed that the average diameter of PSZFe particles was 30 nm,the structure of iron in PSZFe magnetic particles was α-Fe.The formation of a PSZ layer on nanosize Fe particles enchanced the corrosion resistance of PSZFe.In addition,PSZFe particles coated with 3 wt% PSZ demonstrated high corrosion resistance and fine microwave-absorbing ability as well.The reflection loss was less than -10 dB in the range of 9^8～16 GHz,and a reflection loss value of -20 dB was detected at 13 GHz.
