The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microsc...The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Dynamic Contact Angle Analysis (DCAA). The results of characterization indicated that the oxygen and nitrogen contents in carbon fiber surface were significantly increased by electrochemical treatment, and amide groups was introduced onto it, which was related with the electrolyte. The AFM photographs illustrated that the roughness of the fiber surface was also increased. The wettibality of the fibers was improved after treatment because the surface energy especially the polar part of it was increased.展开更多
Water exploits an essential part in all the durable development, the exploitation of this natural resource, its management and its position, its mineralization, its underground course and the mode o fits resurgence. T...Water exploits an essential part in all the durable development, the exploitation of this natural resource, its management and its position, its mineralization, its underground course and the mode o fits resurgence. The area of Gafsa is known by its very important hydrous potential which is geographically in the zone of transition between central Tunisia and the Saharan platform, these two great fields are separated by the fault of Gafsa which plays an important part in the structuring of the basins of the area, the hydrous resources of Gafsa make subsoil water the principal source of supply water, in the absence of an important network of surface. The zones of studies present requirements out of water which do not cease growing with the progress of the industrial activities and the concentration of the agricultural activities： The objective of this work is to analyze the water of the various zones of the area of Gafsa and to treat it to make it possible most drinkable. The analyzes like measurement of pH, measurement of electric conductivity and measurement of dry residue were made in the laboratory of the chemical group of Mdhila in Tunisia and in laboratory of Ion exchanger Materials of Vitry in France, the processes of treatment as opposite osmosis are also programmed in this same laboratory. The results are very encouraging to start the study and the design of a station of potabilisation of water in the area of Gafsa.展开更多
The effect of different binders on light hydrocarbon aromatization performance of the HZSM-5 catalyst was investigated. Physicochemical properties of the catalysts, such as the specific surface area, pore volume and a...The effect of different binders on light hydrocarbon aromatization performance of the HZSM-5 catalyst was investigated. Physicochemical properties of the catalysts, such as the specific surface area, pore volume and acidity, etc., were characterized to correlate with their aromatization performance data. The results showed that the pore structure of Al2O3 could significantly affect the catalyst performance. As the accessible pore diameter of the catalyst increased from 8.0 nm to 9.0 nm, the light aromatics yield increased by 2.7 percentage points, while the operating time of the catalyst nearly doubled. In addition, catalysts prepared with SiO2 and aluminum phosphate was more active and stable than that prepared with Al2O3, of which the light aromatics yield enhanced 6---8 percentage points and the rtm length, or seivice eife run length nearly doubled.展开更多
Effects of silylation on surface properties and catalytic performance of Zn-IM5 for butane aromatization were studied in this paper. Collidine-IR and NH3-TPD analyses revealed that the silylation treatment not only de...Effects of silylation on surface properties and catalytic performance of Zn-IM5 for butane aromatization were studied in this paper. Collidine-IR and NH3-TPD analyses revealed that the silylation treatment not only decreased the quantity of both strong and weak acid sites but also led to a slightly reduced intensity of weak acidity. Silylation of the catalyst promoted the selectivity of BTX by narrowing the channel and cutting the acidity. The effect of temperature of silylation and amount of Si loading were evaluated. The best condition has specified a temperature of 50 ℃ and a SiO_2 loading of 4.0%.展开更多
Pd-only three-way catalyst （TWC）, Pd supported on washcoating （the mixture of alumina and Ce-Zr solid solution）/cordierite, was prepared and its catalytic performance and the operation window （2-value） at 450 ℃...Pd-only three-way catalyst （TWC）, Pd supported on washcoating （the mixture of alumina and Ce-Zr solid solution）/cordierite, was prepared and its catalytic performance and the operation window （2-value） at 450 ℃ were evaluated with the simulated automotive exhaust feed gas. Surfactants such as Tween-80 and Span-20 were added in the process of preparing the catalyst in order to improve the thermal stability and catalytic performance of Pd-only TWC. The fresh and aged catalysts at 1000 ℃ for 4 h were characterized by low-temperature N2 adsorption, XRD, XPS, and H2-TPR techniques. The results show that the presence of surfactants in the synthesis slurry could influence the physicochemical properties of the final Pd-only TWC. The FTS catalyst prepared with the mixed surfactant of Tween-80 and Span-20 exhibited excellent three-way catalytic performance. After being aged at 1000℃ for 4 h, the catalytic performances of Pd-only TWCs slightly decreased, but the FTS catalyst still demonstrated higher catalytic performance and better thermal stability compared with the Pd-only catalysts prepared with single surfactant or without any surfactant. And the FTS catalyst has a wider 2 value （operation window） than other catalysts, even after being aged at 1000℃.展开更多
Installation of impervious surface in urban area prevents the exchange of material and energy between soil and other environmental counterparts,thereby resulting in negative effects on soil function and urban environm...Installation of impervious surface in urban area prevents the exchange of material and energy between soil and other environmental counterparts,thereby resulting in negative effects on soil function and urban environment.Soil samples were collected at 0-20cm depth in Nanjing City,China,in which seven sites were selected for urban open soils,and fourteen sites with similar parent material were selected for the impervious-covered soils,to examine the effect of impervious surface on soil properties and microbial activities,and to determine the most important soil properties associated with soil organic carbon(SOC)transformation in the urban soils covered by impervious surfaces.Soil organic carbon and water-soluble organic carbon(WSOC)concentrations,potential carbon(C)and nitrogen(N)mineralization rates,basal respiration,and physicochemical properties with respect to C transformation were measured.Installation of impervious surface severely affected soil physicochemical properties and microbial activities,e.g.,it significantly decreased total N contents,potential C mineralization and basal respiration rate(P<0.01),while increased pH,clay and Olsen-P concentrations.Soil organic carbon in the sealed soils at 0-20 cm was 2.35 kg m^(-2),which was significantly lower than the value of 4.52 kg m^(-2)in the open soils(P<0.05).Canonical correlation analysis showed WSOC played a major role in determining SOC transformation in the impervious-covered soil,and it was highly correlated with total N content and potential C mineralization rate.These findings demonstrate that installation of impervious surface in urban area,which will result in decreases of SOC and total N concentrations and soil microbial activities,has certain negative consequences for soil fertility and long-term storage of SOC.展开更多
Two-dimensional(2 D) transition metal phosphides(TMPs) are predicted with many novel properties and various applications. As a member of TMPs family, molybdenum phosphide(MoP) exhibits many exotic physicochemical prop...Two-dimensional(2 D) transition metal phosphides(TMPs) are predicted with many novel properties and various applications. As a member of TMPs family, molybdenum phosphide(MoP) exhibits many exotic physicochemical properties. However, the synthesis of high-quality2 D MoP single crystals is not reported due to the lack of reliable fabrication method, which limits the exploration of 2 D MoP. Here, we report the growth of high-quality ultrathin MoP single crystals with thickness down to 10 nm on liquid metals via chemical vapor deposition(CVD). The smooth surface of liquid Ga is regarded as a suitable growth substrate for producing 2 D MoP single crystals. The Mo source diffuses toward the Ga surface due to the high surface energy to react with phosphorus source, thus to fabricate ultrathin MoP single crystals. Then, we study the second harmonic generation(SHG) of 2 D MoP for the first time due to its intrinsic noncentrosymmetric structure. Our study provides an new approach to synthesize and explore other 2 D TMPs for future applications.展开更多
基金Sponsored by the Scientific Research Foundation of Harbin Institute of Technology(Grant No. HIT. 2003.57)
文摘The surface properties of PAN-based carbon fibers electrochemically treated in aqueous ammonium bicarbonate before and after treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Dynamic Contact Angle Analysis (DCAA). The results of characterization indicated that the oxygen and nitrogen contents in carbon fiber surface were significantly increased by electrochemical treatment, and amide groups was introduced onto it, which was related with the electrolyte. The AFM photographs illustrated that the roughness of the fiber surface was also increased. The wettibality of the fibers was improved after treatment because the surface energy especially the polar part of it was increased.
文摘Water exploits an essential part in all the durable development, the exploitation of this natural resource, its management and its position, its mineralization, its underground course and the mode o fits resurgence. The area of Gafsa is known by its very important hydrous potential which is geographically in the zone of transition between central Tunisia and the Saharan platform, these two great fields are separated by the fault of Gafsa which plays an important part in the structuring of the basins of the area, the hydrous resources of Gafsa make subsoil water the principal source of supply water, in the absence of an important network of surface. The zones of studies present requirements out of water which do not cease growing with the progress of the industrial activities and the concentration of the agricultural activities： The objective of this work is to analyze the water of the various zones of the area of Gafsa and to treat it to make it possible most drinkable. The analyzes like measurement of pH, measurement of electric conductivity and measurement of dry residue were made in the laboratory of the chemical group of Mdhila in Tunisia and in laboratory of Ion exchanger Materials of Vitry in France, the processes of treatment as opposite osmosis are also programmed in this same laboratory. The results are very encouraging to start the study and the design of a station of potabilisation of water in the area of Gafsa.
文摘The effect of different binders on light hydrocarbon aromatization performance of the HZSM-5 catalyst was investigated. Physicochemical properties of the catalysts, such as the specific surface area, pore volume and acidity, etc., were characterized to correlate with their aromatization performance data. The results showed that the pore structure of Al2O3 could significantly affect the catalyst performance. As the accessible pore diameter of the catalyst increased from 8.0 nm to 9.0 nm, the light aromatics yield increased by 2.7 percentage points, while the operating time of the catalyst nearly doubled. In addition, catalysts prepared with SiO2 and aluminum phosphate was more active and stable than that prepared with Al2O3, of which the light aromatics yield enhanced 6---8 percentage points and the rtm length, or seivice eife run length nearly doubled.
基金financially supported by the Opening Project of the State Key Laboratory of Catalytic Material and Reaction Engineering of Sinopec Research Institute of Petroleum Processing. (No. 33600000-14-ZC0607-0010)
文摘Effects of silylation on surface properties and catalytic performance of Zn-IM5 for butane aromatization were studied in this paper. Collidine-IR and NH3-TPD analyses revealed that the silylation treatment not only decreased the quantity of both strong and weak acid sites but also led to a slightly reduced intensity of weak acidity. Silylation of the catalyst promoted the selectivity of BTX by narrowing the channel and cutting the acidity. The effect of temperature of silylation and amount of Si loading were evaluated. The best condition has specified a temperature of 50 ℃ and a SiO_2 loading of 4.0%.
基金financially supported by the National Basic Research Program of China(2010CB732300)the National Natural Science Foundation of China(21273150)the National High Technology Research and Development Program of China(2011AA03A406)
文摘Pd-only three-way catalyst （TWC）, Pd supported on washcoating （the mixture of alumina and Ce-Zr solid solution）/cordierite, was prepared and its catalytic performance and the operation window （2-value） at 450 ℃ were evaluated with the simulated automotive exhaust feed gas. Surfactants such as Tween-80 and Span-20 were added in the process of preparing the catalyst in order to improve the thermal stability and catalytic performance of Pd-only TWC. The fresh and aged catalysts at 1000 ℃ for 4 h were characterized by low-temperature N2 adsorption, XRD, XPS, and H2-TPR techniques. The results show that the presence of surfactants in the synthesis slurry could influence the physicochemical properties of the final Pd-only TWC. The FTS catalyst prepared with the mixed surfactant of Tween-80 and Span-20 exhibited excellent three-way catalytic performance. After being aged at 1000℃ for 4 h, the catalytic performances of Pd-only TWCs slightly decreased, but the FTS catalyst still demonstrated higher catalytic performance and better thermal stability compared with the Pd-only catalysts prepared with single surfactant or without any surfactant. And the FTS catalyst has a wider 2 value （operation window） than other catalysts, even after being aged at 1000℃.
基金Surpported by the National Natural Science Foundation of China(No.41001047)
文摘Installation of impervious surface in urban area prevents the exchange of material and energy between soil and other environmental counterparts,thereby resulting in negative effects on soil function and urban environment.Soil samples were collected at 0-20cm depth in Nanjing City,China,in which seven sites were selected for urban open soils,and fourteen sites with similar parent material were selected for the impervious-covered soils,to examine the effect of impervious surface on soil properties and microbial activities,and to determine the most important soil properties associated with soil organic carbon(SOC)transformation in the urban soils covered by impervious surfaces.Soil organic carbon and water-soluble organic carbon(WSOC)concentrations,potential carbon(C)and nitrogen(N)mineralization rates,basal respiration,and physicochemical properties with respect to C transformation were measured.Installation of impervious surface severely affected soil physicochemical properties and microbial activities,e.g.,it significantly decreased total N contents,potential C mineralization and basal respiration rate(P<0.01),while increased pH,clay and Olsen-P concentrations.Soil organic carbon in the sealed soils at 0-20 cm was 2.35 kg m^(-2),which was significantly lower than the value of 4.52 kg m^(-2)in the open soils(P<0.05).Canonical correlation analysis showed WSOC played a major role in determining SOC transformation in the impervious-covered soil,and it was highly correlated with total N content and potential C mineralization rate.These findings demonstrate that installation of impervious surface in urban area,which will result in decreases of SOC and total N concentrations and soil microbial activities,has certain negative consequences for soil fertility and long-term storage of SOC.
基金supported by the National Natural Science Foundation of China (21673161 and 21905210)the Sino-German Center for Research Promotion (GZ 1400)。
文摘Two-dimensional(2 D) transition metal phosphides(TMPs) are predicted with many novel properties and various applications. As a member of TMPs family, molybdenum phosphide(MoP) exhibits many exotic physicochemical properties. However, the synthesis of high-quality2 D MoP single crystals is not reported due to the lack of reliable fabrication method, which limits the exploration of 2 D MoP. Here, we report the growth of high-quality ultrathin MoP single crystals with thickness down to 10 nm on liquid metals via chemical vapor deposition(CVD). The smooth surface of liquid Ga is regarded as a suitable growth substrate for producing 2 D MoP single crystals. The Mo source diffuses toward the Ga surface due to the high surface energy to react with phosphorus source, thus to fabricate ultrathin MoP single crystals. Then, we study the second harmonic generation(SHG) of 2 D MoP for the first time due to its intrinsic noncentrosymmetric structure. Our study provides an new approach to synthesize and explore other 2 D TMPs for future applications.
