The Er3+doped double perovskite Ba_(2)CaWO_(6) crystal is a promising ratiometric thermometer based on the fluorescence intensity ratio(FIR) of transitions from ^(2)H_(11/2) and ^(4)S_(3/2) to the lowered ^(4)I_(15/2)...The Er3+doped double perovskite Ba_(2)CaWO_(6) crystal is a promising ratiometric thermometer based on the fluorescence intensity ratio(FIR) of transitions from ^(2)H_(11/2) and ^(4)S_(3/2) to the lowered ^(4)I_(15/2) level.However,the Ca^(2+) vacancy defect caused by the charge difference between rare-earth ions and the substituted alkaline-earth ions gives rise to the non-radiative probability and limits the thermal sensitivity.Here,the up-conversion luminescence and thermometric performance of Er^(3+),Yb^(3+) dopedBa_(2)CaWO_(6) are tuned by tri-doping with alkaline ions.The Ca^(2+) vacancy defect can be eliminated by the introduction of Na^(+),which occupies the Ca^(2+) site when it is doped into Ba_(2)CaWO_(6) with Er^(3+) and Yb^(3+).On the contrary,the doping of Cs^(+) into Ba_(2)CaWO_(6) with Er^(3+) and Yb^(3+) enhances the defect concentration because it occupies the site of Ba^(2+).Thus,the tri-doping of Na^(+) reduces the non-radiative probability and enhances the quantum efficiency of Er^(3+),leading to the improvement of the thermometric sensitivity of Ba_(2)CaWO_(6).As a result,we get an excellent thermometric Ba_(2)CaWO_(6):8%Yb^(3+),3.5%Er^(3+),6%Na^(+) powder with a luminescence lifetime of 515 μs and maximum thermal sensitivity(S_(r)) of 1.45%/K,which is more than three times higher than that of the BCWO:Er^(3+) powder.展开更多
AIM:To observe the long-term clinical efficacy of intravitreal injections of conbercept,a novel vascular growth factor inhibitor,for the treatment of pathological myopia choroidal neovascularization(PM-CNV).METHODS:A ...AIM:To observe the long-term clinical efficacy of intravitreal injections of conbercept,a novel vascular growth factor inhibitor,for the treatment of pathological myopia choroidal neovascularization(PM-CNV).METHODS:A total of 67 eyes(from 67 patients;mean age,54.90±12.7y)with PM-CNV were retrospectively researched.Based on the different schemes used for the administration of the drug,the patients were divided into two groups:group A(n=35;average age,53.31±13.6y;average diopter,9.25±1.72 D),which received only one injection of pro re nata(PRN;1+PRN regimen),and group B(n=32;average age,56.49±11.8y;average diopter,9.63±2.24 D),which received one injection per month for 3mo(3+PRN regimen).Best-corrected visual acuity(BCVA)analysis,intraocular pressure(IOP)examination,slit-lamp microscopy,fundus examination and optical coherence tomography were per formed at each follow-up.The recurrence and treatment times of CNV were recorded.The patients were followed up for at least 12mo.RESULTS:The BCVA was increased in 29 eyes(82.9%)in group A and 30 eyes(93.75%)in group B;no increase or decrease was observed in 6(17.1%)and 2(6.25%)eyes in groups A and B,respectively.The BCVA(log MAR)values before treatment(0.67±0.48 and 0.71±0.56)were significantly higher than those 12mo after treatment(0.31±0.26 and 0.33±0.17)in groups A and B,respectively(P<0.05).The mean central macular thickness(CMT)values had significantly decreased from 346.49±65.99 and 360.10±82.31μm at baseline to 257.29±40.47 and 251.97±48.26μm in groups A and B,respectively,after 12mo of treatment.A total of 21 eyes in group A needed reinjection(60%;average number of injections,2.51±0.98);the corresponding values in group B were 6 eyes(18.75%;average number of injections,3.74±1.22).There were no adverse ocular and systemic complications during the treatment and follow-up.CONCLUSION:Intravitreal injection of conbercept with 1+PRN or 3+PRN improve the visual acuity,reduce macular edema and reduce the level of CMT in patients with PM-CNV.The 3+PRN regimen demonstrates a lower recurrence rate of CNV than the 1+PRN regimen,but requires more treatment.However,both treatment regimens demonstrate long-term safety and efficacy for the treatment of PM-CNV.展开更多
Chalcogenide glasses （ChGs） are a promising candidate for applications in nonlinear photonic devices. In this paper, we review the research progress of the third-order optical nonlinearity （TONL） of ChGs from the ...Chalcogenide glasses （ChGs） are a promising candidate for applications in nonlinear photonic devices. In this paper, we review the research progress of the third-order optical nonlinearity （TONL） of ChGs from the following three aspects： chemical composition, excitation condition, and post processing. The deficiencies in previous studies and further research of the TONL property of ChGs are also discussed.展开更多
An efficient photocatalytic CO_(2) reduction has been reported in ZIF-67-derived-Co nanoparticles(NPs)encapsulated in nitrogen-doped carbon layers(N-C/Co).This work demonstrates that the pyrolysis temperature is cruci...An efficient photocatalytic CO_(2) reduction has been reported in ZIF-67-derived-Co nanoparticles(NPs)encapsulated in nitrogen-doped carbon layers(N-C/Co).This work demonstrates that the pyrolysis temperature is crucial in tuning the grain size and components of metallic Co^(0) of N-C/Co composite catalysts,which optimizes their photocatalytic activities.Syntheses were conducted at 600,700,and 800℃ giving the N-C/Co-600,N-C/Co-700,and N-C/Co-800 samples,respectively.N-C layers can well wrap the Co NPs obtained at a low pyrolysis temperature(600℃)owing to their smaller grains than those of other samples.A high metallic Co^(0) content in the N-C/Co-600 sample can be attributed to the effective inhibition of surface oxidation.By contrast,the surface CoOx oxides in the N-C/Co-700 and N-C/Co-800 samples cover inside Co cores,inhibiting charge separation and transfer.As a result,the N-C/Co-600 sample yields the best photocatalytic activity.The carbon monoxide and hydrogen generation rates are as high as 1.62×10^(4) and 2.01×10^(4)μmol g^(−1)h^(−1),respectively.Additionally,the Co NPs make composite catalysts magnetic,enabling rapid and facile recovery of catalysts with the assistance of an external magnetic field.This work is expected to provide an instructive guideline for designing metal-organic framework-derived carbon/metal composite catalysts.展开更多
For the proportional directional valve controlled by two proportional solenoids, the normal control method(NCM) energizes only one solenoid at a time. The performance of the valve is greatly influenced by the nonlinea...For the proportional directional valve controlled by two proportional solenoids, the normal control method(NCM) energizes only one solenoid at a time. The performance of the valve is greatly influenced by the nonlinearity of the proportional solenoid, such as dead zone and low force gain with a small current, and this effect cannot be eliminated by a simple dead-zone current compensation. To avoid this disadvantage, we propose the differential control method(DCM). By employing DCM, the controller outputs differential signals to simultaneously energize both solenoids of the proportional valve, and the operating point is found by analyzing the force output of the two solenoids to make a minimum variation of the current force gain. The comparisons of the valve response characteristics are made between NCM and DCM by nonlinear dynamic simulation and experiments. Simulation and experimental results show that by using DCM, the frequency response of the valve is greatly enhanced, especially when the input is small, which means that the dynamic characteristics of the proportional valve are improved.展开更多
基金Project supported by the National Natural Science Foundation of China (51972061,22109025,22171045,52072076)。
文摘The Er3+doped double perovskite Ba_(2)CaWO_(6) crystal is a promising ratiometric thermometer based on the fluorescence intensity ratio(FIR) of transitions from ^(2)H_(11/2) and ^(4)S_(3/2) to the lowered ^(4)I_(15/2) level.However,the Ca^(2+) vacancy defect caused by the charge difference between rare-earth ions and the substituted alkaline-earth ions gives rise to the non-radiative probability and limits the thermal sensitivity.Here,the up-conversion luminescence and thermometric performance of Er^(3+),Yb^(3+) dopedBa_(2)CaWO_(6) are tuned by tri-doping with alkaline ions.The Ca^(2+) vacancy defect can be eliminated by the introduction of Na^(+),which occupies the Ca^(2+) site when it is doped into Ba_(2)CaWO_(6) with Er^(3+) and Yb^(3+).On the contrary,the doping of Cs^(+) into Ba_(2)CaWO_(6) with Er^(3+) and Yb^(3+) enhances the defect concentration because it occupies the site of Ba^(2+).Thus,the tri-doping of Na^(+) reduces the non-radiative probability and enhances the quantum efficiency of Er^(3+),leading to the improvement of the thermometric sensitivity of Ba_(2)CaWO_(6).As a result,we get an excellent thermometric Ba_(2)CaWO_(6):8%Yb^(3+),3.5%Er^(3+),6%Na^(+) powder with a luminescence lifetime of 515 μs and maximum thermal sensitivity(S_(r)) of 1.45%/K,which is more than three times higher than that of the BCWO:Er^(3+) powder.
文摘AIM:To observe the long-term clinical efficacy of intravitreal injections of conbercept,a novel vascular growth factor inhibitor,for the treatment of pathological myopia choroidal neovascularization(PM-CNV).METHODS:A total of 67 eyes(from 67 patients;mean age,54.90±12.7y)with PM-CNV were retrospectively researched.Based on the different schemes used for the administration of the drug,the patients were divided into two groups:group A(n=35;average age,53.31±13.6y;average diopter,9.25±1.72 D),which received only one injection of pro re nata(PRN;1+PRN regimen),and group B(n=32;average age,56.49±11.8y;average diopter,9.63±2.24 D),which received one injection per month for 3mo(3+PRN regimen).Best-corrected visual acuity(BCVA)analysis,intraocular pressure(IOP)examination,slit-lamp microscopy,fundus examination and optical coherence tomography were per formed at each follow-up.The recurrence and treatment times of CNV were recorded.The patients were followed up for at least 12mo.RESULTS:The BCVA was increased in 29 eyes(82.9%)in group A and 30 eyes(93.75%)in group B;no increase or decrease was observed in 6(17.1%)and 2(6.25%)eyes in groups A and B,respectively.The BCVA(log MAR)values before treatment(0.67±0.48 and 0.71±0.56)were significantly higher than those 12mo after treatment(0.31±0.26 and 0.33±0.17)in groups A and B,respectively(P<0.05).The mean central macular thickness(CMT)values had significantly decreased from 346.49±65.99 and 360.10±82.31μm at baseline to 257.29±40.47 and 251.97±48.26μm in groups A and B,respectively,after 12mo of treatment.A total of 21 eyes in group A needed reinjection(60%;average number of injections,2.51±0.98);the corresponding values in group B were 6 eyes(18.75%;average number of injections,3.74±1.22).There were no adverse ocular and systemic complications during the treatment and follow-up.CONCLUSION:Intravitreal injection of conbercept with 1+PRN or 3+PRN improve the visual acuity,reduce macular edema and reduce the level of CMT in patients with PM-CNV.The 3+PRN regimen demonstrates a lower recurrence rate of CNV than the 1+PRN regimen,but requires more treatment.However,both treatment regimens demonstrate long-term safety and efficacy for the treatment of PM-CNV.
基金Project supported by the National Natural Science Foundation of China(Grant No.61675106)the National Key Research and Development Program of China(Grant No.2016YFB0303803)the K C Wong Magna Fund in Ningbo University
文摘Chalcogenide glasses （ChGs） are a promising candidate for applications in nonlinear photonic devices. In this paper, we review the research progress of the third-order optical nonlinearity （TONL） of ChGs from the following three aspects： chemical composition, excitation condition, and post processing. The deficiencies in previous studies and further research of the TONL property of ChGs are also discussed.
基金financially supported by the National Key Research and Development Program of China(2020YFA0710303)the National Natural Science Foundation of China(51972061,U1905215 and 52072076)。
文摘An efficient photocatalytic CO_(2) reduction has been reported in ZIF-67-derived-Co nanoparticles(NPs)encapsulated in nitrogen-doped carbon layers(N-C/Co).This work demonstrates that the pyrolysis temperature is crucial in tuning the grain size and components of metallic Co^(0) of N-C/Co composite catalysts,which optimizes their photocatalytic activities.Syntheses were conducted at 600,700,and 800℃ giving the N-C/Co-600,N-C/Co-700,and N-C/Co-800 samples,respectively.N-C layers can well wrap the Co NPs obtained at a low pyrolysis temperature(600℃)owing to their smaller grains than those of other samples.A high metallic Co^(0) content in the N-C/Co-600 sample can be attributed to the effective inhibition of surface oxidation.By contrast,the surface CoOx oxides in the N-C/Co-700 and N-C/Co-800 samples cover inside Co cores,inhibiting charge separation and transfer.As a result,the N-C/Co-600 sample yields the best photocatalytic activity.The carbon monoxide and hydrogen generation rates are as high as 1.62×10^(4) and 2.01×10^(4)μmol g^(−1)h^(−1),respectively.Additionally,the Co NPs make composite catalysts magnetic,enabling rapid and facile recovery of catalysts with the assistance of an external magnetic field.This work is expected to provide an instructive guideline for designing metal-organic framework-derived carbon/metal composite catalysts.
基金Project supported by the National Natural Science Foundation of China(No.51221004)the Program for Zhejiang Leading Team of S&T Innovation(No.2010R50036)
文摘For the proportional directional valve controlled by two proportional solenoids, the normal control method(NCM) energizes only one solenoid at a time. The performance of the valve is greatly influenced by the nonlinearity of the proportional solenoid, such as dead zone and low force gain with a small current, and this effect cannot be eliminated by a simple dead-zone current compensation. To avoid this disadvantage, we propose the differential control method(DCM). By employing DCM, the controller outputs differential signals to simultaneously energize both solenoids of the proportional valve, and the operating point is found by analyzing the force output of the two solenoids to make a minimum variation of the current force gain. The comparisons of the valve response characteristics are made between NCM and DCM by nonlinear dynamic simulation and experiments. Simulation and experimental results show that by using DCM, the frequency response of the valve is greatly enhanced, especially when the input is small, which means that the dynamic characteristics of the proportional valve are improved.
