Carbon fibers （CFs） were surface treated with air-oxidation, rare earths （RE） after air-oxidation, and rare earths, respectively. Erichsen test was conducted to study the interfacial adhesion of PTFE composites fi...Carbon fibers （CFs） were surface treated with air-oxidation, rare earths （RE） after air-oxidation, and rare earths, respectively. Erichsen test was conducted to study the interfacial adhesion of PTFE composites filled with carbon fibers treated with different treatment methods. Tribological properties of the PTFE composites, sliding against GCr15 steel under water-lubricated condition, were investigated on a reciprocating ball-on-disk UMT-2MT tribometer. The worn surfaces of the composites were examined using scanning electron microscopy. Experimental results reveal that RE treatment is superior to air oxidation in promoting tribological properties of CF reinforced PTFE （CF/PTFE） composite. The friction and wear properties of PTFE composite filled with RE treated CF are the best of the PTFE composites. RE treatment is more effective than air oxidation to improve the tribological properties of CF/PTFE composite owing to the effective improvement of interfacial adhesion between carbon fibers and PTFE matrix.展开更多
At present,rare earth application in wastewater treatment has become more and more widely,according to the fact that the Ce(IV) has the strong oxidation ability under acid condition,we have studied the application of ...At present,rare earth application in wastewater treatment has become more and more widely,according to the fact that the Ce(IV) has the strong oxidation ability under acid condition,we have studied the application of Ce(IV) in industrial wastewater treatment originally.Results showed that oxidation-reduction reaction occurred between Ce(IV) and the organic compounds or other reducing substances in industrial wastewater,thereby the colority and CODcr reduced effectively.Ce(IV) formed [Ce(OH)x·nH2O](4-x)+ after hydrolyzation and Ce(III) obtained after Ce(IV) reduction formed [Ce(OH)x·nH2O](3-x)+ after hydrolyzation,these hydrate had big specific surface area,could adsorb the suspension substances and removed toxic or harmful ions in industrial wastewater.After treatment by Ce(IV),the analytical results of industrial wastewater are as follows:The CODcr became 58 mg/L from 1646 mg/L,the total COD removal efficiency was more than 95.0%.Turbidity reduced to no more than 10NTU from 87NTU.The chroma became 6 degree from 26 degree,suspension substances content decreased to no more than 2 mg/L from 36 mg/L,and total arsenic and fluorion became 【0.05 mg/L and 【0.10 mg/L from 0.60 and 15.3 mg/L.Total cadmium reduced to 0.01 mg/L from the 0.58 mg/L.These all indicated that Ce(IV) was one kind of latent good water treatment chemical.展开更多
Magnesium and rare earth mixed oxides（Mg3 REOx（RE=La, Y. Ce）） were prepared and characterized by Xray diffraction（XRD）, N_2 adsorption-desorption, infrared spectra and microcalorimetry of CO_2. The results revea...Magnesium and rare earth mixed oxides（Mg3 REOx（RE=La, Y. Ce）） were prepared and characterized by Xray diffraction（XRD）, N_2 adsorption-desorption, infrared spectra and microcalorimetry of CO_2. The results reveal that the Mg_3 CeO_x catalyst is present in the form of Mg-Ce-O solid solution,while the Mg3 LaOx and Mg_3 YO_x catalysts are probably rare earth oxides dispersed on MgO surface. As a result, among the calcined Mg_3 REO_x catalysts, the Mg_3 CeO_x catalyst presents the highest rate constant for acetone aldolization, which is well correlated to its more homogeneous distribution of basic sites. In contrary, the Mg_3 YO_x catalyst exhibit the lowest catalytic activity for acetone aldolization. Upon hydration pre-treatment, the basic properties on the surface of the Mg_3 REO_x catalysts were changed markedly. The Mg_3 YO_x catalyst after hydration treatment shows the highest amount of basic sites on catalyst surface, and then exhibits the highest activity among the hydrated Mg_3 REO_x catalysts. These results make it possible to fine-tune basic sites for acetone aldolization.展开更多
基金financially supported by the National Key Basic Research Program of China(No.2014CB643403)the National Science Fund for Distinguished Young Scholars(No.51225401)
基金Project supported bythe National Natural Science Foundation of China (50275093)
文摘Carbon fibers （CFs） were surface treated with air-oxidation, rare earths （RE） after air-oxidation, and rare earths, respectively. Erichsen test was conducted to study the interfacial adhesion of PTFE composites filled with carbon fibers treated with different treatment methods. Tribological properties of the PTFE composites, sliding against GCr15 steel under water-lubricated condition, were investigated on a reciprocating ball-on-disk UMT-2MT tribometer. The worn surfaces of the composites were examined using scanning electron microscopy. Experimental results reveal that RE treatment is superior to air oxidation in promoting tribological properties of CF reinforced PTFE （CF/PTFE） composite. The friction and wear properties of PTFE composite filled with RE treated CF are the best of the PTFE composites. RE treatment is more effective than air oxidation to improve the tribological properties of CF/PTFE composite owing to the effective improvement of interfacial adhesion between carbon fibers and PTFE matrix.
文摘At present,rare earth application in wastewater treatment has become more and more widely,according to the fact that the Ce(IV) has the strong oxidation ability under acid condition,we have studied the application of Ce(IV) in industrial wastewater treatment originally.Results showed that oxidation-reduction reaction occurred between Ce(IV) and the organic compounds or other reducing substances in industrial wastewater,thereby the colority and CODcr reduced effectively.Ce(IV) formed [Ce(OH)x·nH2O](4-x)+ after hydrolyzation and Ce(III) obtained after Ce(IV) reduction formed [Ce(OH)x·nH2O](3-x)+ after hydrolyzation,these hydrate had big specific surface area,could adsorb the suspension substances and removed toxic or harmful ions in industrial wastewater.After treatment by Ce(IV),the analytical results of industrial wastewater are as follows:The CODcr became 58 mg/L from 1646 mg/L,the total COD removal efficiency was more than 95.0%.Turbidity reduced to no more than 10NTU from 87NTU.The chroma became 6 degree from 26 degree,suspension substances content decreased to no more than 2 mg/L from 36 mg/L,and total arsenic and fluorion became 【0.05 mg/L and 【0.10 mg/L from 0.60 and 15.3 mg/L.Total cadmium reduced to 0.01 mg/L from the 0.58 mg/L.These all indicated that Ce(IV) was one kind of latent good water treatment chemical.
基金Project supported by National Basic Research Program of China(2010CB732300)111 Project(B08021)China Scholarship Council for the Joint-Training Scholarship Program with Institut de Recherches sur la Catalyse et l'Environnement de Lyon(IRCELYON)and Universite Claude Bernard Lyon 1(UCBL1)
文摘Magnesium and rare earth mixed oxides（Mg3 REOx（RE=La, Y. Ce）） were prepared and characterized by Xray diffraction（XRD）, N_2 adsorption-desorption, infrared spectra and microcalorimetry of CO_2. The results reveal that the Mg_3 CeO_x catalyst is present in the form of Mg-Ce-O solid solution,while the Mg3 LaOx and Mg_3 YO_x catalysts are probably rare earth oxides dispersed on MgO surface. As a result, among the calcined Mg_3 REO_x catalysts, the Mg_3 CeO_x catalyst presents the highest rate constant for acetone aldolization, which is well correlated to its more homogeneous distribution of basic sites. In contrary, the Mg_3 YO_x catalyst exhibit the lowest catalytic activity for acetone aldolization. Upon hydration pre-treatment, the basic properties on the surface of the Mg_3 REO_x catalysts were changed markedly. The Mg_3 YO_x catalyst after hydration treatment shows the highest amount of basic sites on catalyst surface, and then exhibits the highest activity among the hydrated Mg_3 REO_x catalysts. These results make it possible to fine-tune basic sites for acetone aldolization.
