Scanning electron microscopy and X-ray energy dispersive spectrum analysis show that the clusters of intermetallic AlFeSi particle are distributed on or near the aluminum foil stock surfaces heterogeneously. 3D finite...Scanning electron microscopy and X-ray energy dispersive spectrum analysis show that the clusters of intermetallic AlFeSi particle are distributed on or near the aluminum foil stock surfaces heterogeneously. 3D finite element modeling shows that these clusters of hard particles induce the fracture of the nano-scale lubricant oil film at first and further lead to severe deformation in the nearby aluminum foil substrate along the rolling direction. Consequently, the optical property in this region differs from that in the surroundings, resulting in surface defects.展开更多
Kerosene-alumina nanofluid flow and heat transfer in the presence of magnetic field are studied. The basic partial differential equations are reduced to ordinary differential equations which are solved semi analytical...Kerosene-alumina nanofluid flow and heat transfer in the presence of magnetic field are studied. The basic partial differential equations are reduced to ordinary differential equations which are solved semi analytically using differential transformation method. Velocity and temperature profiles as well as the skin friction coefficient and the Nusselt number are determined analytically. The influence of pertinent parameters such as magnetic parameter, nanofluid volume fraction, viscosity parameter and Eckert number on the flow and heat transfer characteristics is discussed. Results indicate that skin friction coefficient decreases with increase of magnetic parameter, nanofluid volume fraction and viscosity parameter. Nusselt number increases with increase of magnetic parameter and nanofluid volume fraction while it decreases with increase of Eckert number and viscosity parameter.展开更多
The differences of grain-refining effect between Sc and Ti additions in aluminum,which cannot be substantially explained by traditional theories,were carefully studied.The empirical electron theory(EET) of solids and ...The differences of grain-refining effect between Sc and Ti additions in aluminum,which cannot be substantially explained by traditional theories,were carefully studied.The empirical electron theory(EET) of solids and molecules was employed to calculate the valence electron structures(VES) of Al3Ti and Al3Sc.The conclusions can be drawn that,in the two alloys Al-Ti and Al-Sc,the different valence electron structures of Al3Ti and Al3Sc and the consequent differences of growth habit of the two particles,and the different interfacial electron density between particles and matrix fundamentally lead to the differences of grain-refining effect between Sc and Ti additions on aluminum and make Sr the better grain-refiner of aluminum.展开更多
Due to the biological risks of using the conventional lubricants,the vegetable oils have been considered nowadays.Besides,to improve the tribological properties of the vegetable oils in various applications like metal...Due to the biological risks of using the conventional lubricants,the vegetable oils have been considered nowadays.Besides,to improve the tribological properties of the vegetable oils in various applications like metal forming processes,nanoparticles have been used as additives.This research evaluated the lubrication performance of the Al2O3 and TiO2 nanoparticles dispersed in rapeseed oil during the parallel tubular channel angular pressing (PTCAP) process.The experimental PTCAP tests have been fulfilled under three lubrication conditions and the comparison between the PTCAP processed tubes has been performed in terms of the maximum forming force,surface roughness,and microhardness.The experimental results indicate that adding the mentioned nanoparticles has caused at least a 50% reduction in the maximum deformation load.Moreover,a remarkable decrement in the surface roughness of the formed tubes has been obtained.展开更多
Highly effective production of hydrogen from bio-oil was achieved by using a low-temperature electrochemical catalytic reforming approach over the conventional Ni-based reforming catalyst (NiO-Al2O3), where an AC el...Highly effective production of hydrogen from bio-oil was achieved by using a low-temperature electrochemical catalytic reforming approach over the conventional Ni-based reforming catalyst (NiO-Al2O3), where an AC electronic current passed through the catalyst bed. The promoting effects of current on the bio-oil reforming were studied. It was found that the performance of the bio-oil reforming was remarkably enhanced by the current which passed through the catalyst. The effects of currents on the microcosmic properties of the catalyst, including the Brunauer-Emmett-Teller (BET) surface area, pore diameter, pore volume, the size of the crystallites and the reduction level of NiO into Ni, were carefully characterized by BET, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscope. The desorption of the thermal electrons from the electrified catalyst was directly observed by the TOF (time of flight) measurements. The mechanism of the electrochemical catalytic reforming of bio-oil is discussed based on the above investigation.展开更多
A well core-shell composite of Y@meso-Al with a mesoporous alumina shell and a Y zeolite core was synthesized. The mesoporous alumina shell has a wormhole-like structure with large mesopores. The prepared catalytic cr...A well core-shell composite of Y@meso-Al with a mesoporous alumina shell and a Y zeolite core was synthesized. The mesoporous alumina shell has a wormhole-like structure with large mesopores. The prepared catalytic cracking catalyst using this composite has exhibited excellent catalytic performance for heavy oil cracking thanks to its favorable physicochemical properties, such as high surface area, large pore volume and outstanding acid sites accessibility for large molecules provided by the composite. In comparison with the reference catalyst using pure Y zeolite, the oil conversion achieved by the above-mentioned catalyst increased by 2.73 percentage points, while the heavy oil yield and coke yield decreased by 2.23 percentage points and 1.28 percentage points, respectively, with the light oil yield increasing by 2.27 percentage points.展开更多
The removal of acid compounds (naphthenates) from acidic oil with ionic liquids was systematically investigated. [BMIM]Br-AlCl3 was used to investigate the effect on deacidification of oil. Experimental results show...The removal of acid compounds (naphthenates) from acidic oil with ionic liquids was systematically investigated. [BMIM]Br-AlCl3 was used to investigate the effect on deacidification of oil. Experimental results showed that at a temperature of 323K with a molar ratio of AlCl3 to [BM1M]Br-AlCl3 of 0.2, and a mass ratio of IL to white oil of 4%, the deacidification rate could reach 75.9%. And a reaction time of 4 h was sufficient to achieve the goal. The study on reproducibility of catalytic performance of [BMIM]Br-AlCl3 showed the possibility of using the ionic liquid in the continuous catalytic reaction.展开更多
The properties and blending recipe of petroleum cokes used to make high quality carbon anodes for aluminium electrolysis were studied. Three kinds of green cokes were selected for bench scale study to illustrate the e...The properties and blending recipe of petroleum cokes used to make high quality carbon anodes for aluminium electrolysis were studied. Three kinds of green cokes were selected for bench scale study to illustrate the effects of cokes properties and its blending recipe on anode performances. The results show that impurities derived mainly fi'om cokes remarkably affect the CO2 reactivity and air reactivity of carbon anodes. Ca, Na and V can increase CO2 reactivity of calcined cokes but S has the contrary effect, and the cokes of high V level generally present high air reactivity. The anodes with good quality can be made by properly selecting and scientifically blending of cokes, some poor quality cokes can also be used to produce high quality anodes with a reasonable blending recipe. Na contaminated anodes have high CO2 reactivity and air reactivity, so the recycled anode butts should be well cleaned to reduce Na content before being introduced into anode production, which is especially important to the low S cokes.展开更多
In this paper,an ab initio,local density functional(LDF)method was used to explore the relationship between the molecular properties of additives and the lubricating performance of aluminum rolling oil.The structural ...In this paper,an ab initio,local density functional(LDF)method was used to explore the relationship between the molecular properties of additives and the lubricating performance of aluminum rolling oil.The structural properties of butyl stearate,dodecanol,docosanol,and methyl dodecanoate were studied according to the density functional theory.The calculated data showed that the atoms in or around the functional groups might be likely the reacting sites.Because of the different functional groups and structure of ester and alcohol,two types of complex additives,dodecanol and butyl stearate,methyl dodecanoate and butyl stearate,respectively,were chosen for studying their tribological properties and performing aluminum cold rolling experiments.The test results agreed with the calculated results very well.The complex ester,viz.methyl dodecanoate and butyl stearate,had the best lubricating performance with a friction coefficient of 0.084 1 and a permissive-rolling thickness of 0.040 mm as compared with that of dodecanol-butyl stearate-base oil formulation.展开更多
Static and dynamic contact angles of stock oil and its solutions with additives(fatty acid, fatty alcohol, fatty methyl ester usually used in rolling aluminum) were measured on aluminum surface (Alloy 1145) by ses...Static and dynamic contact angles of stock oil and its solutions with additives(fatty acid, fatty alcohol, fatty methyl ester usually used in rolling aluminum) were measured on aluminum surface (Alloy 1145) by sessile drop technique on an OCA35 dynamic contact angle tester. The effect of additive on the drop spreading was investigated as well. It is shown that the drop spreads very quickly in the first 500 ms after the lubricant contacts with the aluminum surface, and then does slowly later. The dynamic contact angle decreases exponentially with time. In contrast to the stock oil, although addition of polarity additive of long chain alkyl into stock oil is able to decrease the surface tension of solutions, it weakens the wetting dynamic, which results fi'om the adsorption at the expanding solid/liquid interface. Among the same long chain polarity organic compounds used, dynamic wetting decreases in the order of fatty acid, fatty alcohol and fatty ester. The blend of fatty alcohol and fatty methyl ester can improve the oil wetting dynamics and promote the lubricant spreading.展开更多
The dry modification of aluminum hydroxide powders with phosphoric acid and the effects of modification of technological conditions on thermal stability, morphology and oil absorption of aluminum hydroxide powders wer...The dry modification of aluminum hydroxide powders with phosphoric acid and the effects of modification of technological conditions on thermal stability, morphology and oil absorption of aluminum hydroxide powders were investigated. The results show that the increase of mass ratio of phosphoric acid to aluminum hydroxide, the decrease of mass concentration of phosphoric acid and prolongation of mixing time are favorable to the improvement of thermal stability of aluminum hydroxide; when the mass ratio of phosphoric acid to aluminum hydroxide is 5:100, the mass concentration of phosphoric acid is 200 g/L and the mixing time is 10 min, the initial temperature of loss of crystal water in aluminum hydroxide rises from about 192.10 to 208.66 ℃, but the dry modification results in the appearance of agglomeration and macro-aggregate in the modified powders, and the oil absorption of modified powders becomes higher than that of original aluminum hydroxide.展开更多
Observation of fatigue crack initiation and propagation during fatigue test in ALSn20Cu bearing has been presented. Journal center orbit, oil film pressure and stress distribution in alloy layer have been calculated a...Observation of fatigue crack initiation and propagation during fatigue test in ALSn20Cu bearing has been presented. Journal center orbit, oil film pressure and stress distribution in alloy layer have been calculated and are taken as the basis for theoretically simulating the bearing fatigue process. It is found that the calculated results are in good accordance with the experimental results, which provides a feasible way for investigation of fatigue crack propagation process in the bearing.展开更多
The conventional collector for diaspore mineral is oleic acid (OLA), which is highly insoluble and must be used in high dosage in bauxite flotation. Firstly flotation experiments with every reagent (sodium oleate, ...The conventional collector for diaspore mineral is oleic acid (OLA), which is highly insoluble and must be used in high dosage in bauxite flotation. Firstly flotation experiments with every reagent (sodium oleate, tween-20)were carried out and it was shown that sodium oleate was an effective diaspore collector, whereas nonionic surfactant tween-20 showed little collectivity. Then experiments were carried out with sodium oleate as the main collector with the addition of tween-20 to study the influences of potentiator on diaspore flotation. It could be seen from the experiments that potentiator had a marked influence on the recovery of diaspore, which was raised by more than 12 % and that addition sequence also affected the flotation behavior. It gave the best results with the reagents mixed thoroughly before added and the best ratio of collector oleic acid and potentiator tween-20 slLood at 10: 1. From the calculation of the ingredients in the sodium oleate solution, at the pH 9, sodium oleate acted with surface of the mineral with the acid-soap polymer [ HOL ~ OL- ]. Zeta potential test showed that the potentiator promoted the absorption of collector on the mineral surface, which lowered zeta potential. As could be seen from surface tension experiments, the addition of potentiator tween-20 lowered the CMC ( critical micelle concentration) value of oleic acid solution, which was equivalent to raise the power of the agents. By the adsorptive capability tests, with the addition of tween-20, the adsorption of oleic acid on diaspore got more.展开更多
In order to evaluate the role of vanadium in the hydrogenation (HYD) reaction, a series of alumina supported vanadium catalysts were prepared and characterized by SEM, XRD, Raman spectrometry, 51V NMR, XPS, as well as...In order to evaluate the role of vanadium in the hydrogenation (HYD) reaction, a series of alumina supported vanadium catalysts were prepared and characterized by SEM, XRD, Raman spectrometry, 51V NMR, XPS, as well as TPR analyses. The catalytic performance of vanadium in HYD of model molecules (naphthalene) and real feedstock (Kuwait atmospheric residue) was studied after sulfidation of the catalysts. It can be concluded that the HYD capabilities of V/Al2O3 catalysts are lower than that of conventional NiMo/Al2O3 catalyst (RefNiMo). The V/Al2O3 catalysts can only facilitate hydrogenation of the first ring of naphthalene, but have little effect on the further hydrogenation of tetralin. Owing to the different forms of metals and sulfur compounds in residue, the weak HYD activity of V/Al2O3 catalysts is able to facilitate the HDM reaction of the residue, albeit with a slight effect on HDS activity.展开更多
Oiltea camellia (Camellia oleifera Abel.), an aluminium (Al) hyperaccumulator, grows well on acid soils in tropical or subtropical areas. In this study, the growth of oiltea camellia in response to Al application ...Oiltea camellia (Camellia oleifera Abel.), an aluminium (Al) hyperaccumulator, grows well on acid soils in tropical or subtropical areas. In this study, the growth of oiltea camellia in response to Al application and the characteristics of Al uptake and accumulation were investigated using laboratory and field experiments. The growth of oiltea camellia seedlings in the nutrient solution tended to be stimulated by addition of Al. Results of the field experiment showed that oiltea camellia accumulated 11 000 mg kg-1 Al in leaves within 10 months, and the average rate of Al accumulation in new leaves was about 1100 mg kg-1 month-1; however, the monthly rate varied and was highest in spring and autumn. The results of the laboratory experiment on Al uptake by oiltea camellia seedlings in CaC12 solutions with various forms of Al showed that large amounts of Al supplied as Al3+ and Al complexes Al-malate (1:1) and Al-F (1:1) were infiuxed into oiltea camellia roots, whereas Al supplied as Al-citrate (1:1), Al-F (1:6), Al-oxalate (1:3), and Al-oxalate (1:1) complexes exhibited low affinity to oiltea camellia roots. The kinetics of Al3+ cumulative uptake in excised roots and intact plants showed a biphasic pattern, with an initial rapid phase followed by a slow phase. The Al cumulative uptake was unaffected by low temperature, which indicated that Al uptake in oiltea camellia was a passive process. The efficient influx of Al into the roots and the high transport rate in specific seasons were presumed to account for the plentiful Al accumulation in leaves of oiltea camellia.展开更多
基金Project(51074117)supported by the National Natural Science Foundation of ChinaProject(2009CDA044)supported by the Foundation for Distinguished Young Scientists of Hubei Province,ChinaProjects(201104493,20100471161)supported by the China Postdoctoral Science Foundation
文摘Scanning electron microscopy and X-ray energy dispersive spectrum analysis show that the clusters of intermetallic AlFeSi particle are distributed on or near the aluminum foil stock surfaces heterogeneously. 3D finite element modeling shows that these clusters of hard particles induce the fracture of the nano-scale lubricant oil film at first and further lead to severe deformation in the nearby aluminum foil substrate along the rolling direction. Consequently, the optical property in this region differs from that in the surroundings, resulting in surface defects.
文摘Kerosene-alumina nanofluid flow and heat transfer in the presence of magnetic field are studied. The basic partial differential equations are reduced to ordinary differential equations which are solved semi analytically using differential transformation method. Velocity and temperature profiles as well as the skin friction coefficient and the Nusselt number are determined analytically. The influence of pertinent parameters such as magnetic parameter, nanofluid volume fraction, viscosity parameter and Eckert number on the flow and heat transfer characteristics is discussed. Results indicate that skin friction coefficient decreases with increase of magnetic parameter, nanofluid volume fraction and viscosity parameter. Nusselt number increases with increase of magnetic parameter and nanofluid volume fraction while it decreases with increase of Eckert number and viscosity parameter.
基金Project(20050003042) supported by Research Fund for the Doctoral Program of Higher Education of China
文摘The differences of grain-refining effect between Sc and Ti additions in aluminum,which cannot be substantially explained by traditional theories,were carefully studied.The empirical electron theory(EET) of solids and molecules was employed to calculate the valence electron structures(VES) of Al3Ti and Al3Sc.The conclusions can be drawn that,in the two alloys Al-Ti and Al-Sc,the different valence electron structures of Al3Ti and Al3Sc and the consequent differences of growth habit of the two particles,and the different interfacial electron density between particles and matrix fundamentally lead to the differences of grain-refining effect between Sc and Ti additions on aluminum and make Sr the better grain-refiner of aluminum.
文摘Due to the biological risks of using the conventional lubricants,the vegetable oils have been considered nowadays.Besides,to improve the tribological properties of the vegetable oils in various applications like metal forming processes,nanoparticles have been used as additives.This research evaluated the lubrication performance of the Al2O3 and TiO2 nanoparticles dispersed in rapeseed oil during the parallel tubular channel angular pressing (PTCAP) process.The experimental PTCAP tests have been fulfilled under three lubrication conditions and the comparison between the PTCAP processed tubes has been performed in terms of the maximum forming force,surface roughness,and microhardness.The experimental results indicate that adding the mentioned nanoparticles has caused at least a 50% reduction in the maximum deformation load.Moreover,a remarkable decrement in the surface roughness of the formed tubes has been obtained.
基金ACKNOWLEDGMENTS This work was supported by the National Basic Research Program of China (No.2007CB210206), the National High Tech Research and Development Program (No.2006AA05Z118), the General Program of the National Natural Science Foundation of China (No.50772107), and the Green Agriculture Scientific Research Demonstration Program (No.2007-15).
文摘Highly effective production of hydrogen from bio-oil was achieved by using a low-temperature electrochemical catalytic reforming approach over the conventional Ni-based reforming catalyst (NiO-Al2O3), where an AC electronic current passed through the catalyst bed. The promoting effects of current on the bio-oil reforming were studied. It was found that the performance of the bio-oil reforming was remarkably enhanced by the current which passed through the catalyst. The effects of currents on the microcosmic properties of the catalyst, including the Brunauer-Emmett-Teller (BET) surface area, pore diameter, pore volume, the size of the crystallites and the reduction level of NiO into Ni, were carefully characterized by BET, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscope. The desorption of the thermal electrons from the electrified catalyst was directly observed by the TOF (time of flight) measurements. The mechanism of the electrochemical catalytic reforming of bio-oil is discussed based on the above investigation.
基金financially supported by the Department of Science and Technology Management of Petro China (No. 2011B-2404-0102)
文摘A well core-shell composite of Y@meso-Al with a mesoporous alumina shell and a Y zeolite core was synthesized. The mesoporous alumina shell has a wormhole-like structure with large mesopores. The prepared catalytic cracking catalyst using this composite has exhibited excellent catalytic performance for heavy oil cracking thanks to its favorable physicochemical properties, such as high surface area, large pore volume and outstanding acid sites accessibility for large molecules provided by the composite. In comparison with the reference catalyst using pure Y zeolite, the oil conversion achieved by the above-mentioned catalyst increased by 2.73 percentage points, while the heavy oil yield and coke yield decreased by 2.23 percentage points and 1.28 percentage points, respectively, with the light oil yield increasing by 2.27 percentage points.
文摘The removal of acid compounds (naphthenates) from acidic oil with ionic liquids was systematically investigated. [BMIM]Br-AlCl3 was used to investigate the effect on deacidification of oil. Experimental results showed that at a temperature of 323K with a molar ratio of AlCl3 to [BM1M]Br-AlCl3 of 0.2, and a mass ratio of IL to white oil of 4%, the deacidification rate could reach 75.9%. And a reaction time of 4 h was sufficient to achieve the goal. The study on reproducibility of catalytic performance of [BMIM]Br-AlCl3 showed the possibility of using the ionic liquid in the continuous catalytic reaction.
文摘The properties and blending recipe of petroleum cokes used to make high quality carbon anodes for aluminium electrolysis were studied. Three kinds of green cokes were selected for bench scale study to illustrate the effects of cokes properties and its blending recipe on anode performances. The results show that impurities derived mainly fi'om cokes remarkably affect the CO2 reactivity and air reactivity of carbon anodes. Ca, Na and V can increase CO2 reactivity of calcined cokes but S has the contrary effect, and the cokes of high V level generally present high air reactivity. The anodes with good quality can be made by properly selecting and scientifically blending of cokes, some poor quality cokes can also be used to produce high quality anodes with a reasonable blending recipe. Na contaminated anodes have high CO2 reactivity and air reactivity, so the recycled anode butts should be well cleaned to reduce Na content before being introduced into anode production, which is especially important to the low S cokes.
基金the financial support of this study provided by the National Natural Science Foundation of China(No.51274037)the Cooperation Program between USTB and SINOPEC(No.112116)
文摘In this paper,an ab initio,local density functional(LDF)method was used to explore the relationship between the molecular properties of additives and the lubricating performance of aluminum rolling oil.The structural properties of butyl stearate,dodecanol,docosanol,and methyl dodecanoate were studied according to the density functional theory.The calculated data showed that the atoms in or around the functional groups might be likely the reacting sites.Because of the different functional groups and structure of ester and alcohol,two types of complex additives,dodecanol and butyl stearate,methyl dodecanoate and butyl stearate,respectively,were chosen for studying their tribological properties and performing aluminum cold rolling experiments.The test results agreed with the calculated results very well.The complex ester,viz.methyl dodecanoate and butyl stearate,had the best lubricating performance with a friction coefficient of 0.084 1 and a permissive-rolling thickness of 0.040 mm as compared with that of dodecanol-butyl stearate-base oil formulation.
基金Project (01C26224300195) supported by the National Innovation Fund for Technology Based Firms
文摘Static and dynamic contact angles of stock oil and its solutions with additives(fatty acid, fatty alcohol, fatty methyl ester usually used in rolling aluminum) were measured on aluminum surface (Alloy 1145) by sessile drop technique on an OCA35 dynamic contact angle tester. The effect of additive on the drop spreading was investigated as well. It is shown that the drop spreads very quickly in the first 500 ms after the lubricant contacts with the aluminum surface, and then does slowly later. The dynamic contact angle decreases exponentially with time. In contrast to the stock oil, although addition of polarity additive of long chain alkyl into stock oil is able to decrease the surface tension of solutions, it weakens the wetting dynamic, which results fi'om the adsorption at the expanding solid/liquid interface. Among the same long chain polarity organic compounds used, dynamic wetting decreases in the order of fatty acid, fatty alcohol and fatty ester. The blend of fatty alcohol and fatty methyl ester can improve the oil wetting dynamics and promote the lubricant spreading.
基金Project(06SK2011) supported by the Science and Technology Program of Hunan Province, China
文摘The dry modification of aluminum hydroxide powders with phosphoric acid and the effects of modification of technological conditions on thermal stability, morphology and oil absorption of aluminum hydroxide powders were investigated. The results show that the increase of mass ratio of phosphoric acid to aluminum hydroxide, the decrease of mass concentration of phosphoric acid and prolongation of mixing time are favorable to the improvement of thermal stability of aluminum hydroxide; when the mass ratio of phosphoric acid to aluminum hydroxide is 5:100, the mass concentration of phosphoric acid is 200 g/L and the mixing time is 10 min, the initial temperature of loss of crystal water in aluminum hydroxide rises from about 192.10 to 208.66 ℃, but the dry modification results in the appearance of agglomeration and macro-aggregate in the modified powders, and the oil absorption of modified powders becomes higher than that of original aluminum hydroxide.
基金This paper is financially supported by Trans Century Training Programme Foundation for the Talents by the State Education Commission,PR China.
文摘Observation of fatigue crack initiation and propagation during fatigue test in ALSn20Cu bearing has been presented. Journal center orbit, oil film pressure and stress distribution in alloy layer have been calculated and are taken as the basis for theoretically simulating the bearing fatigue process. It is found that the calculated results are in good accordance with the experimental results, which provides a feasible way for investigation of fatigue crack propagation process in the bearing.
基金National Key Fundamental Research and Development Program(No.2005cbc237601)
文摘The conventional collector for diaspore mineral is oleic acid (OLA), which is highly insoluble and must be used in high dosage in bauxite flotation. Firstly flotation experiments with every reagent (sodium oleate, tween-20)were carried out and it was shown that sodium oleate was an effective diaspore collector, whereas nonionic surfactant tween-20 showed little collectivity. Then experiments were carried out with sodium oleate as the main collector with the addition of tween-20 to study the influences of potentiator on diaspore flotation. It could be seen from the experiments that potentiator had a marked influence on the recovery of diaspore, which was raised by more than 12 % and that addition sequence also affected the flotation behavior. It gave the best results with the reagents mixed thoroughly before added and the best ratio of collector oleic acid and potentiator tween-20 slLood at 10: 1. From the calculation of the ingredients in the sodium oleate solution, at the pH 9, sodium oleate acted with surface of the mineral with the acid-soap polymer [ HOL ~ OL- ]. Zeta potential test showed that the potentiator promoted the absorption of collector on the mineral surface, which lowered zeta potential. As could be seen from surface tension experiments, the addition of potentiator tween-20 lowered the CMC ( critical micelle concentration) value of oleic acid solution, which was equivalent to raise the power of the agents. By the adsorptive capability tests, with the addition of tween-20, the adsorption of oleic acid on diaspore got more.
基金supported by the National Basic Research Program of China(973 Program No.2012CB224802)
文摘In order to evaluate the role of vanadium in the hydrogenation (HYD) reaction, a series of alumina supported vanadium catalysts were prepared and characterized by SEM, XRD, Raman spectrometry, 51V NMR, XPS, as well as TPR analyses. The catalytic performance of vanadium in HYD of model molecules (naphthalene) and real feedstock (Kuwait atmospheric residue) was studied after sulfidation of the catalysts. It can be concluded that the HYD capabilities of V/Al2O3 catalysts are lower than that of conventional NiMo/Al2O3 catalyst (RefNiMo). The V/Al2O3 catalysts can only facilitate hydrogenation of the first ring of naphthalene, but have little effect on the further hydrogenation of tetralin. Owing to the different forms of metals and sulfur compounds in residue, the weak HYD activity of V/Al2O3 catalysts is able to facilitate the HDM reaction of the residue, albeit with a slight effect on HDS activity.
基金Supported by the National Natural Science Foundation of China (Nos.40901139, 41025005, and 30821140538)the Knowledge Innovation Program of the Chinese Academy of Sciences (No.ISSASIP0708)
文摘Oiltea camellia (Camellia oleifera Abel.), an aluminium (Al) hyperaccumulator, grows well on acid soils in tropical or subtropical areas. In this study, the growth of oiltea camellia in response to Al application and the characteristics of Al uptake and accumulation were investigated using laboratory and field experiments. The growth of oiltea camellia seedlings in the nutrient solution tended to be stimulated by addition of Al. Results of the field experiment showed that oiltea camellia accumulated 11 000 mg kg-1 Al in leaves within 10 months, and the average rate of Al accumulation in new leaves was about 1100 mg kg-1 month-1; however, the monthly rate varied and was highest in spring and autumn. The results of the laboratory experiment on Al uptake by oiltea camellia seedlings in CaC12 solutions with various forms of Al showed that large amounts of Al supplied as Al3+ and Al complexes Al-malate (1:1) and Al-F (1:1) were infiuxed into oiltea camellia roots, whereas Al supplied as Al-citrate (1:1), Al-F (1:6), Al-oxalate (1:3), and Al-oxalate (1:1) complexes exhibited low affinity to oiltea camellia roots. The kinetics of Al3+ cumulative uptake in excised roots and intact plants showed a biphasic pattern, with an initial rapid phase followed by a slow phase. The Al cumulative uptake was unaffected by low temperature, which indicated that Al uptake in oiltea camellia was a passive process. The efficient influx of Al into the roots and the high transport rate in specific seasons were presumed to account for the plentiful Al accumulation in leaves of oiltea camellia.