V-Ti-Fe master alloys were prepared by metaUothermic reduction method, and the influences of the mass ratio of V205 to TiO2, Al and Al-Mg alloy addition amounts on the metal recovery rates and alloy compositions were ...V-Ti-Fe master alloys were prepared by metaUothermic reduction method, and the influences of the mass ratio of V205 to TiO2, Al and Al-Mg alloy addition amounts on the metal recovery rates and alloy compositions were investigated. The results show that appropriate technological parameters are： the mass ratio of V205 to TiO2 is 0.5：1, Al addition represents 95% of the theoretical value, and the Al-Mg alloy addition amount is one third that of the Al addition. The results from energy spectrum analysis show that V and Fe distribute uniformly in the prepared alloy, while the segregation for Ti, i.e. Ti-rich phase is detected. A spray refming process was carried out to reduce the impurity contents of Al and O in the prepared alloys. The Al content drops from 4.27% to 1.86%, and the O content drops from 2.10% to 0.91% after the refining process.展开更多
A required finite element method（FEM） model applicable for narrow gap CMT and CMT＋P MIX welding was established based on the interactions between arc,base metal and filler metal.A novel method of simplifying wire f...A required finite element method（FEM） model applicable for narrow gap CMT and CMT＋P MIX welding was established based on the interactions between arc,base metal and filler metal.A novel method of simplifying wire feeding pulses and heat input pulses was supposed under the conduction of equivalent input.The method together with composed double-ellipse heat sources was included in the model.The model was employed in the investigation of thermal cycling and the identification of the softened zone of AA7A52 base plates.Low-frequency behavior emerged in the form of low-cooling rate sects,which were not expected under experimental conditions.The softened zone including the quenched zone and averaging zone of the base plate was much wider internal the base plate than that close to the surfaces.The reliability of the predictions in thermal cycling was supported by infrared imaging test results of the thermal cycle process.展开更多
The distribution and characteristics of nonmetallic micro-inclusions of GCr15 bearing steel were explored through metallographic area method in virtue of tracer method and electronic microscope.The results show that t...The distribution and characteristics of nonmetallic micro-inclusions of GCr15 bearing steel were explored through metallographic area method in virtue of tracer method and electronic microscope.The results show that the micro-inclusions,of which the average value is 0.032%,are mainly the compounds formed via the adsorption/aggregation of multielement deoxidized compounds and secondarily deoxidized products on tundish liquid level.The micro-inclusions of diameters from 0 to 5 μm are 92.5% in total,which basically determines the characteristics of inclusions distribution in casting slab.The inclusions of diameters more than 10 μm only account for less than 1% in total,which have little influence on steel quality.The relationship between equilibrium compositions of the first deoxidation products and molten steel compositions was also calculated based on thermodynamic theory.展开更多
The corrosive electrochemistry of jamesonite was studied by cyclic voltammetry. Every peak in voltammograms was identified through thermodynamic calculation. The results show an irreversible electrode process by the s...The corrosive electrochemistry of jamesonite was studied by cyclic voltammetry. Every peak in voltammograms was identified through thermodynamic calculation. The results show an irreversible electrode process by the strong adsorption of oxidation elemental sulfur on jamesonite. A deficient-metal and sulfur-rich compound is formed under the potential of 80 mV at pH 6.86. The passive action by elemental sulfur occurs from 80 to 470 mV and S2O2-3, SO2-4 are produced at potential over 470 mV. The anodic peak producing SO2-4 is inhibited due to the deposition of PbSO4 at higher potential in Na2SO4 solution. The corrosive action of jamesonite becomes strong and the redox characterization similar to PbS, FeS and Sb2S3 appears at pH 9.18.展开更多
The hydrothermal reaction of Na2MoO4 . 2H(2)O, V2O5 and en in water gave rise to a graphite-shaped vanadate [H3O](2)V3O8 1, which is doped with molybdenum. Compound 1 crystallizes in tetragonal system, space group P4b...The hydrothermal reaction of Na2MoO4 . 2H(2)O, V2O5 and en in water gave rise to a graphite-shaped vanadate [H3O](2)V3O8 1, which is doped with molybdenum. Compound 1 crystallizes in tetragonal system, space group P4bm, H6O10V2.9Mo0.1, M-r = 323.37, a = 8.904(1), c = 5.573(1)Angstrom, V = 441.8(1)Angstrom (3), Z = 2, D-c = 2.431 g.cm(-3), mu = 3.137 mm(-1), F(000) = 314, the final R = 0.0477, wR = 0.0993 for 260 observed reflections. Its two-dimensional framework is built up by corner-shared ((VO4)-O-V) tetrahedra and ((VO5)-O-IV) square pyramids with all of the terminal oxygen atoms toward the same orientation and further connected inta three-dimensional framework through hydrogen bonding between the protoned water molecules.展开更多
In order to speed up the production and save more energy in hot stamping process,the induction heating technology as a new effective heating method is considerable.Finite element(FE)-simulation and a series of experim...In order to speed up the production and save more energy in hot stamping process,the induction heating technology as a new effective heating method is considerable.Finite element(FE)-simulation and a series of experiments are carried out to research the temperature homogenization of induction heating with the face inductor.It is found the edge effect has a notable influence on the temperature distribution.Results concerning the mechanical properties of the stamped part as well as surface characteristics will be presented and discussed.展开更多
Less-expensive but efficient electrocatalysts are essential to accelerate the commercialization of fuel cells.Herein,ultrathin PdPb nanowires(PdPb NWs)with a diameter of around 3.5 nm were prepared by using a one-step...Less-expensive but efficient electrocatalysts are essential to accelerate the commercialization of fuel cells.Herein,ultrathin PdPb nanowires(PdPb NWs)with a diameter of around 3.5 nm were prepared by using a one-step hydrothermal method.The introduction of Pb in Pd-based bimetallic nanostructures produced high differences in the morphology from Pd nanoparticles(NPs)to various PdPb NWs.All the as-prepared PdPb NWs exhibited better electrocatalytic activity and durability than Pd NPs due to the synergistic effect.Especially,Pd65Pb35 possessed the highest current density of about 3460 mA mgPd^−1 for the ethanol electrooxidation which was around 6.3 times higher than commercial Pd/C.The high-performance of Pd65Pb35 is attributed to the defect-rich and stable nanowire structure with optimized surface atomic arrangement,as evidenced by high resolution transmission electron microscopy measurements and long-time treatment in an acidic media.The differences in the morphologies and electrocatalytic activities of PdPb NWs with varied Pb contents have also been discussed and analyzed.展开更多
基金Project (2006AA068128) supported by the High-tech Research and Development Program of China
文摘V-Ti-Fe master alloys were prepared by metaUothermic reduction method, and the influences of the mass ratio of V205 to TiO2, Al and Al-Mg alloy addition amounts on the metal recovery rates and alloy compositions were investigated. The results show that appropriate technological parameters are： the mass ratio of V205 to TiO2 is 0.5：1, Al addition represents 95% of the theoretical value, and the Al-Mg alloy addition amount is one third that of the Al addition. The results from energy spectrum analysis show that V and Fe distribute uniformly in the prepared alloy, while the segregation for Ti, i.e. Ti-rich phase is detected. A spray refming process was carried out to reduce the impurity contents of Al and O in the prepared alloys. The Al content drops from 4.27% to 1.86%, and the O content drops from 2.10% to 0.91% after the refining process.
基金Project (9140C850205120C8501) supported by the Major Program of National Key Laboratory of Remanufacturing and the Army Foundation Project of China
文摘A required finite element method（FEM） model applicable for narrow gap CMT and CMT＋P MIX welding was established based on the interactions between arc,base metal and filler metal.A novel method of simplifying wire feeding pulses and heat input pulses was supposed under the conduction of equivalent input.The method together with composed double-ellipse heat sources was included in the model.The model was employed in the investigation of thermal cycling and the identification of the softened zone of AA7A52 base plates.Low-frequency behavior emerged in the form of low-cooling rate sects,which were not expected under experimental conditions.The softened zone including the quenched zone and averaging zone of the base plate was much wider internal the base plate than that close to the surfaces.The reliability of the predictions in thermal cycling was supported by infrared imaging test results of the thermal cycle process.
基金Supported by Natural Science Foundation of Hebei Province (No.502265)
文摘The distribution and characteristics of nonmetallic micro-inclusions of GCr15 bearing steel were explored through metallographic area method in virtue of tracer method and electronic microscope.The results show that the micro-inclusions,of which the average value is 0.032%,are mainly the compounds formed via the adsorption/aggregation of multielement deoxidized compounds and secondarily deoxidized products on tundish liquid level.The micro-inclusions of diameters from 0 to 5 μm are 92.5% in total,which basically determines the characteristics of inclusions distribution in casting slab.The inclusions of diameters more than 10 μm only account for less than 1% in total,which have little influence on steel quality.The relationship between equilibrium compositions of the first deoxidation products and molten steel compositions was also calculated based on thermodynamic theory.
文摘The corrosive electrochemistry of jamesonite was studied by cyclic voltammetry. Every peak in voltammograms was identified through thermodynamic calculation. The results show an irreversible electrode process by the strong adsorption of oxidation elemental sulfur on jamesonite. A deficient-metal and sulfur-rich compound is formed under the potential of 80 mV at pH 6.86. The passive action by elemental sulfur occurs from 80 to 470 mV and S2O2-3, SO2-4 are produced at potential over 470 mV. The anodic peak producing SO2-4 is inhibited due to the deposition of PbSO4 at higher potential in Na2SO4 solution. The corrosive action of jamesonite becomes strong and the redox characterization similar to PbS, FeS and Sb2S3 appears at pH 9.18.
基金the State Education Ministry the State Personal Ministry+1 种基金 National Natural Science Foundation of China (20073048) the NSF of Fujian and the Chinese Academy of Sciences.
文摘The hydrothermal reaction of Na2MoO4 . 2H(2)O, V2O5 and en in water gave rise to a graphite-shaped vanadate [H3O](2)V3O8 1, which is doped with molybdenum. Compound 1 crystallizes in tetragonal system, space group P4bm, H6O10V2.9Mo0.1, M-r = 323.37, a = 8.904(1), c = 5.573(1)Angstrom, V = 441.8(1)Angstrom (3), Z = 2, D-c = 2.431 g.cm(-3), mu = 3.137 mm(-1), F(000) = 314, the final R = 0.0477, wR = 0.0993 for 260 observed reflections. Its two-dimensional framework is built up by corner-shared ((VO4)-O-V) tetrahedra and ((VO5)-O-IV) square pyramids with all of the terminal oxygen atoms toward the same orientation and further connected inta three-dimensional framework through hydrogen bonding between the protoned water molecules.
基金National Natural Science Foundation of China （No. 51275185, No. 51405171） Graduate Innovation and Entrepreneurship Fund of Huazhong University of Science and Technology （No. 0109070112） Fundamental Research Funds for the Central Universities （No. 0118110621）
文摘In order to speed up the production and save more energy in hot stamping process,the induction heating technology as a new effective heating method is considerable.Finite element(FE)-simulation and a series of experiments are carried out to research the temperature homogenization of induction heating with the face inductor.It is found the edge effect has a notable influence on the temperature distribution.Results concerning the mechanical properties of the stamped part as well as surface characteristics will be presented and discussed.
基金This work was financially supported by the National Natural Science Foundation of China(21773133)Taishan Scholars Advantageous and Distinctive Discipline Program for supporting the research team of energy storage materials of Shandong Province,China.
文摘Less-expensive but efficient electrocatalysts are essential to accelerate the commercialization of fuel cells.Herein,ultrathin PdPb nanowires(PdPb NWs)with a diameter of around 3.5 nm were prepared by using a one-step hydrothermal method.The introduction of Pb in Pd-based bimetallic nanostructures produced high differences in the morphology from Pd nanoparticles(NPs)to various PdPb NWs.All the as-prepared PdPb NWs exhibited better electrocatalytic activity and durability than Pd NPs due to the synergistic effect.Especially,Pd65Pb35 possessed the highest current density of about 3460 mA mgPd^−1 for the ethanol electrooxidation which was around 6.3 times higher than commercial Pd/C.The high-performance of Pd65Pb35 is attributed to the defect-rich and stable nanowire structure with optimized surface atomic arrangement,as evidenced by high resolution transmission electron microscopy measurements and long-time treatment in an acidic media.The differences in the morphologies and electrocatalytic activities of PdPb NWs with varied Pb contents have also been discussed and analyzed.
