Faraday isolators can prevent the front-end system from disturbance and damage caused by a back-reflected beam,so they are important elements in laser systems.As magneto-optical materials are the most important compon...Faraday isolators can prevent the front-end system from disturbance and damage caused by a back-reflected beam,so they are important elements in laser systems.As magneto-optical materials are the most important component in Faraday isolators,the studies on magneto-optical materials have attracted much attention these years.Tb_(3)Al_(5)O_(12)(TAG)ceramics are considered to be one of the most promising magneto-optical materials for visible to near-infrared wavelength band application because of their outstanding comprehensive magneto-optical performance.However,the optical quality of TAG ceramics needs further optimization to meet the application requirements.In this work,high optical quality(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)(x=0,0.05,0.1,0.2,and 0.3)magneto-optical ceramics were fabricated successfully by solid-state reaction sintering combined with hot isostatic pressing(HIP)post-treatment.All the ceramics obtained showed a single garnet phase for different values of x in the range studied.The addition of Y_(2)O_(3) was found to suppress the secondary phase and improve optical quality significantly.The ceramic samples obtained had clear grain boundaries and possessed the in-line transmittance values of 82.9%at 1064 nm and 82.2%at 633 nm,respectively.The Verdet constants of(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)ceramics with x=0,0.05,0.1,0.2,and 0.3 were−188.1,−175.4,−168.5,−143.0,and−119.9 rad/(T·m),respectively.The thermal conductivity of TAG ceramics was found to be 5.23 W/(m·K)at 25℃,and when 20%Y was substituted in place of Tb,the thermal conductivity decreased by only 9.4%.展开更多
Based on monolayer dispersion theory,Co_(3)O_(4)/ZSM-5 catalysts with different loadings have been prepared for selective catalytic reduction of nitrogen oxides by ammonia.Co_(3)O_(4)can spontaneously disperse on HZSM...Based on monolayer dispersion theory,Co_(3)O_(4)/ZSM-5 catalysts with different loadings have been prepared for selective catalytic reduction of nitrogen oxides by ammonia.Co_(3)O_(4)can spontaneously disperse on HZSM-5 support with a monolayer dispersion threshold of 0.061 mmol 100 m^(-2),equaling to a weight percentage around 4.5%.It has been revealed that the quantities of surface active oxygen(O_(2)^(-))and acid sites are crucial for the reaction,which can adsorb and activate NO_(x)and NH_(3)reactants effectively.Below the monolayer dispersion threshold,Co_(3)O_(4)is finely dispersed as sub-monolayers or monolayers and in an amorphous state,which is favorable to generate the two kinds of active sites,hence promoting the performance of ammonia selective catalytic reduction of nitrogen oxide.However,the formation of crystalline Co_(3)O_(4)above the capacity is harmful to the reaction performance.4%Co_(3)O_(4)/ZSM-5,the catalyst close to the monolayer dispersion capacity,possesses the most abundant active O_(2)^(-)species and acidic sites,thereby demonstrating the best reaction performance in all the samples.It is proposed the optimal Co_(3)O_(4)/ZSM-5 catalyst can be prepared by loading the capacity amount of Co_(3)O_(4)onto HZSM-5 support.展开更多
基金the National Key R&D Program of China(Nos.2021YFE0104800 and 2023YFB3812000)the General Project of Shanghai Natural Science Foundation(No.22ZR1471500)+2 种基金the International Partnership Program of Chinese Academy of Sciences(No.121631KYSB20200039)the International Cooperation Project of Shanghai Science and Technology Commission(No.20520750200)and National Center for Research and Development(Contract No.WPC2/1/SCAPOL/2021).Partial work was also financially supported by the Hengdian Group.
文摘Faraday isolators can prevent the front-end system from disturbance and damage caused by a back-reflected beam,so they are important elements in laser systems.As magneto-optical materials are the most important component in Faraday isolators,the studies on magneto-optical materials have attracted much attention these years.Tb_(3)Al_(5)O_(12)(TAG)ceramics are considered to be one of the most promising magneto-optical materials for visible to near-infrared wavelength band application because of their outstanding comprehensive magneto-optical performance.However,the optical quality of TAG ceramics needs further optimization to meet the application requirements.In this work,high optical quality(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)(x=0,0.05,0.1,0.2,and 0.3)magneto-optical ceramics were fabricated successfully by solid-state reaction sintering combined with hot isostatic pressing(HIP)post-treatment.All the ceramics obtained showed a single garnet phase for different values of x in the range studied.The addition of Y_(2)O_(3) was found to suppress the secondary phase and improve optical quality significantly.The ceramic samples obtained had clear grain boundaries and possessed the in-line transmittance values of 82.9%at 1064 nm and 82.2%at 633 nm,respectively.The Verdet constants of(Tb_(1−x)Y_(x))_(3)Al_(5)O_(12)ceramics with x=0,0.05,0.1,0.2,and 0.3 were−188.1,−175.4,−168.5,−143.0,and−119.9 rad/(T·m),respectively.The thermal conductivity of TAG ceramics was found to be 5.23 W/(m·K)at 25℃,and when 20%Y was substituted in place of Tb,the thermal conductivity decreased by only 9.4%.
基金the financial supporting by the National Natural Science Foundation of China(Grant Nos.21962009,22172071,22102069,22062013)the Natural Science Foundation of Jiangxi Province(Grant Nos.20202BAB203006,20181ACB20005)the Key Laboratory Foundation of Jiangxi Province for Environment and Energy Catalysis(Grant No.20181BCD40004).
文摘Based on monolayer dispersion theory,Co_(3)O_(4)/ZSM-5 catalysts with different loadings have been prepared for selective catalytic reduction of nitrogen oxides by ammonia.Co_(3)O_(4)can spontaneously disperse on HZSM-5 support with a monolayer dispersion threshold of 0.061 mmol 100 m^(-2),equaling to a weight percentage around 4.5%.It has been revealed that the quantities of surface active oxygen(O_(2)^(-))and acid sites are crucial for the reaction,which can adsorb and activate NO_(x)and NH_(3)reactants effectively.Below the monolayer dispersion threshold,Co_(3)O_(4)is finely dispersed as sub-monolayers or monolayers and in an amorphous state,which is favorable to generate the two kinds of active sites,hence promoting the performance of ammonia selective catalytic reduction of nitrogen oxide.However,the formation of crystalline Co_(3)O_(4)above the capacity is harmful to the reaction performance.4%Co_(3)O_(4)/ZSM-5,the catalyst close to the monolayer dispersion capacity,possesses the most abundant active O_(2)^(-)species and acidic sites,thereby demonstrating the best reaction performance in all the samples.It is proposed the optimal Co_(3)O_(4)/ZSM-5 catalyst can be prepared by loading the capacity amount of Co_(3)O_(4)onto HZSM-5 support.
