The iso-activity of[Ce]of samples reached in multiple-hole-graphite crucibles by controlling the oxygen potential through the reaction 2[Ce]+3CO=Ce_(2)O_(3)+3C.Combining conjugate gradient method of solving ill-condit...The iso-activity of[Ce]of samples reached in multiple-hole-graphite crucibles by controlling the oxygen potential through the reaction 2[Ce]+3CO=Ce_(2)O_(3)+3C.Combining conjugate gradient method of solving ill-conditioned equations,the activity interaction coeffients between Ce and Al.Si,Ti and Fe alloying elements were determined.The equilibrium constant of the reaction 2[Ce]+3[O]=Ce_(2)O_(3)and the standard free energy of formation of Ce203 in liquid Cu were obtained at 1.200 C.展开更多
The effects of Ce and Ti additions on the microstructures and mechanical properties of an Al-Cu-Mg-Ag alloy have been studied, It has been shown that either Ce or Ti can decrease the as-cast grain size of the Al-Cu-Mg...The effects of Ce and Ti additions on the microstructures and mechanical properties of an Al-Cu-Mg-Ag alloy have been studied, It has been shown that either Ce or Ti can decrease the as-cast grain size of the Al-Cu-Mg-Ag alloy, increase the nucleation ratio for Ω phase as heterogeneous nucleation centers, inhibit the growth of Ω phase during aging, and thus increase the volume fraction and decrease the spacing of Ω phase. These microstructures increase the yield strength and tensile strength. However, if both Ce and Ti are added to the alloy, they form （Ce,Ti）-contained compounds and increase the grain size during casting, but have no effects on the nucleation and the growth of Ω phase during aging. The alloy containing both Ce and Ti has a relatively lower Vicks hardness and strength compared to the alloy containing either Ce or Ti.展开更多
The equilibrium product in Fe-Cu-Ce,Fe-P-Ce or Fe-Ti-Ce solution have ben Mentified to be Ce_2O_2S,but not the intermetallic compounds of Ce against Cu,P or Ti.The equilibrium eonstant of Ce_2O_2S=2[Ce]+2[O]+[S] and t...The equilibrium product in Fe-Cu-Ce,Fe-P-Ce or Fe-Ti-Ce solution have ben Mentified to be Ce_2O_2S,but not the intermetallic compounds of Ce against Cu,P or Ti.The equilibrium eonstant of Ce_2O_2S=2[Ce]+2[O]+[S] and the interaction coefficients between solutes in Fe-base solution have been determined as follows: K_(Ce_2O_2S)=2.57×10^(-5) e_(Ce)^(Cu)=-0.49;e_(Ce)~P=1.77;e_(Ce)^(Ti)=-3.62 e_(Cu)^(Ce)=-0.22;e_P^(Ce)=0.39;e_(Ti)^(Ce)=-1.23 ε_(Ce)^(Cu)=-128.0;ε_(Ce)~P=-224.1;ε_(Ce)^(Ti)=-710.0 Ce decreases the activities of Cu and Ti in Fe-base solution and increases their solubifities,as well as increases the activity of P and decreases its solubility.展开更多
A series of copper-doped Ti-Ce-O_x complex oxide catalysts were synthesized by sol-gel method and evaluated for selective catalytic reduction of NO by NH_3 at low temperature. The promotional effect of copper doping o...A series of copper-doped Ti-Ce-O_x complex oxide catalysts were synthesized by sol-gel method and evaluated for selective catalytic reduction of NO by NH_3 at low temperature. The promotional effect of copper doping on their structure, acidity and catalytic activity were investigated by means of Brumauer-Emmett-Teller（BET）, temperature-programmed reduction（H_2-TPR）, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, temperature programmed desorption（NH_3-TPD） and pyridine adsorption infrared spectrum（Py-IR） technologies. Results showed that the copper additives could improve the low temperature catalytic performance for selective catalytic reduction of Ti-Ce-O_x catalyst and the NO conversion efficiency of Ti-Cu-Ce-O_x catalyst reached above 90% at 150-250 oC（Ti/Cu=4）. The introduction of copper could enhance the redox property of the Ti-Ce-O_x complex oxide catalyst, refine the particle size caused by lattice distortion and oxygen vacancy defect and enhance the acid amount of the Lewis acid site. Moreover, Ti-Cu-Ce-O_x complex oxide catalyst also had good anti-sulfur ability and anti-water influence, when injecting 300 ppm SO_2 and 10 vol.%H_2O, the NO conversion efficiency of Ti-Cu-Ce-O_x catalyst reached 80%.展开更多
文摘The iso-activity of[Ce]of samples reached in multiple-hole-graphite crucibles by controlling the oxygen potential through the reaction 2[Ce]+3CO=Ce_(2)O_(3)+3C.Combining conjugate gradient method of solving ill-conditioned equations,the activity interaction coeffients between Ce and Al.Si,Ti and Fe alloying elements were determined.The equilibrium constant of the reaction 2[Ce]+3[O]=Ce_(2)O_(3)and the standard free energy of formation of Ce203 in liquid Cu were obtained at 1.200 C.
基金This study was financially supported by the State Key Fundamental Research Project on Al, China (No. 2005CB623704).
文摘The effects of Ce and Ti additions on the microstructures and mechanical properties of an Al-Cu-Mg-Ag alloy have been studied, It has been shown that either Ce or Ti can decrease the as-cast grain size of the Al-Cu-Mg-Ag alloy, increase the nucleation ratio for Ω phase as heterogeneous nucleation centers, inhibit the growth of Ω phase during aging, and thus increase the volume fraction and decrease the spacing of Ω phase. These microstructures increase the yield strength and tensile strength. However, if both Ce and Ti are added to the alloy, they form （Ce,Ti）-contained compounds and increase the grain size during casting, but have no effects on the nucleation and the growth of Ω phase during aging. The alloy containing both Ce and Ti has a relatively lower Vicks hardness and strength compared to the alloy containing either Ce or Ti.
文摘The equilibrium product in Fe-Cu-Ce,Fe-P-Ce or Fe-Ti-Ce solution have ben Mentified to be Ce_2O_2S,but not the intermetallic compounds of Ce against Cu,P or Ti.The equilibrium eonstant of Ce_2O_2S=2[Ce]+2[O]+[S] and the interaction coefficients between solutes in Fe-base solution have been determined as follows: K_(Ce_2O_2S)=2.57×10^(-5) e_(Ce)^(Cu)=-0.49;e_(Ce)~P=1.77;e_(Ce)^(Ti)=-3.62 e_(Cu)^(Ce)=-0.22;e_P^(Ce)=0.39;e_(Ti)^(Ce)=-1.23 ε_(Ce)^(Cu)=-128.0;ε_(Ce)~P=-224.1;ε_(Ce)^(Ti)=-710.0 Ce decreases the activities of Cu and Ti in Fe-base solution and increases their solubifities,as well as increases the activity of P and decreases its solubility.
基金supported by the National Natural Science Foundation of China(51272105)the National Key Technology R&D Program of China(2012BAE01B03)+1 种基金the Research Subject of Environmental Protection Department of Jiangsu Province of China(2013006)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘A series of copper-doped Ti-Ce-O_x complex oxide catalysts were synthesized by sol-gel method and evaluated for selective catalytic reduction of NO by NH_3 at low temperature. The promotional effect of copper doping on their structure, acidity and catalytic activity were investigated by means of Brumauer-Emmett-Teller（BET）, temperature-programmed reduction（H_2-TPR）, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, temperature programmed desorption（NH_3-TPD） and pyridine adsorption infrared spectrum（Py-IR） technologies. Results showed that the copper additives could improve the low temperature catalytic performance for selective catalytic reduction of Ti-Ce-O_x catalyst and the NO conversion efficiency of Ti-Cu-Ce-O_x catalyst reached above 90% at 150-250 oC（Ti/Cu=4）. The introduction of copper could enhance the redox property of the Ti-Ce-O_x complex oxide catalyst, refine the particle size caused by lattice distortion and oxygen vacancy defect and enhance the acid amount of the Lewis acid site. Moreover, Ti-Cu-Ce-O_x complex oxide catalyst also had good anti-sulfur ability and anti-water influence, when injecting 300 ppm SO_2 and 10 vol.%H_2O, the NO conversion efficiency of Ti-Cu-Ce-O_x catalyst reached 80%.
