UV-Vis spectroscopy was used to directly determine the concentration of Eu（ Ⅱ） during electroreduction of Eu （ Ⅲ ） in hydrochloric acid medium. Electroreduction was carried out in a flow type electrolyzer with g...UV-Vis spectroscopy was used to directly determine the concentration of Eu（ Ⅱ） during electroreduction of Eu （ Ⅲ ） in hydrochloric acid medium. Electroreduction was carried out in a flow type electrolyzer with glassy carbon cathode at the constant potential of - 800 mV vs. Ag/AgCl. The effects of oxygen and concentration of hydrochloric acid on the system were investigated. For 0.01 mol· L^-1 hydrochloric acid, calibration curves for Eu （Ⅱ） absorption bands at 248 and 320 nm were constructed. Molar absorption coefficients were estimated to be 2016 and 648 L· mol^-1·cm^-1, respectively. The absorbance strongly decreased with decrease in pH of the solution, whereas concentration of chloride had only a negligible effect.展开更多
Nanocrystals and powders of KMgF3 doped with Eu^2＋ were synthesized by the microemulsion method and the selvothermal process, respectively. The emission and excitation spectra of KMgF3： Eu^2＋ phosphors were measure...Nanocrystals and powders of KMgF3 doped with Eu^2＋ were synthesized by the microemulsion method and the selvothermal process, respectively. The emission and excitation spectra of KMgF3： Eu^2＋ phosphors were measured and compared with those of the samples synthesized through a solid state reaction, Bridgman-Stockbarger method, and mild hydrothermal technique. The KMgF3： Eu^2＋ samples synthesized by means of the microemulsion method and the solvothermal process show only a sharp emission peak located at 360 nm in the emission spectra, which arises from the f→f（ ^6P7/2→^8S7/2 ） transition of Eu^2＋ The broad emission bands appear at 420 nm, which arises from Eu^2＋←O^2- cannot be observed（ in the mild hydrothermal and single crystal samples, the emission peak at 420 nm besides the emission of Eu^2＋ at 360 nm is observed）. In the excitation spectrum of the KMgF3 ： Eu^2＋ samples synthesized by the microemulsion method and the solvothermal process, the excitation peaks show an intensive blue shift. The blue shift can be attributed to the lower oxygenic content in the KMgF3 ： Eu^2＋ samples synthesized by the microemulsion method and the selvothermal process.展开更多
The mononuclear cryptate [Eu(H 3L F)(NO 3)(H 2O)](NO 3) 2 and the heterodinuclear cryptate [EuZnL F(DMF)](ClO 4) 2 were synthesized and characterized. The triplet state energy of the cryptand (H 3L F) was ...The mononuclear cryptate [Eu(H 3L F)(NO 3)(H 2O)](NO 3) 2 and the heterodinuclear cryptate [EuZnL F(DMF)](ClO 4) 2 were synthesized and characterized. The triplet state energy of the cryptand (H 3L F) was studied by phosphorescence spectrum. The fluorescent properties of Eu(Ⅲ) cryptates in MeOH solution show that the cryptand (H 3L F) can sensitize the Eu(Ⅲ) ion to luminescence and the introduction of the Zn(Ⅱ) ion into the mononuclear Eu(Ⅲ) cryptate resulted in blue shift of three ligand centered bands, increase of molar absorption coefficient and increase of the luminescence intensity of Eu(Ⅲ).展开更多
The study of rare earth complexes with crown ether arouses people’s great interest. The previous research work was focused on the complexes with single crown ether. Because of the coordinated actions with metal ions ...The study of rare earth complexes with crown ether arouses people’s great interest. The previous research work was focused on the complexes with single crown ether. Because of the coordinated actions with metal ions of the two crown ether cycle activities, the bis (crown ether)has better coordination and selectivity than the single crown ether ligands.展开更多
There has recently been a great deal of interest in time-resolved fluoroimmunoassay（TRFIA）. Not only the content of proteins, but also the content of haptens canbe detected by TRFIA, e.g. progesterone, digoxin, estr...There has recently been a great deal of interest in time-resolved fluoroimmunoassay（TRFIA）. Not only the content of proteins, but also the content of haptens canbe detected by TRFIA, e.g. progesterone, digoxin, estrone-3-glucuronide, 17α-hydroxyprogesterone, prostaglandin F<sub>2α</sub>, etc. We describe here a solid-phase, competitiveTRFIA for angiotensin Ⅱ（AⅡ）. AⅡ is an eight-peptide. It plays an important role展开更多
基金supported by the National Natural Science Foundation of China(20972015)the Natural Science Foundation of Beijing(Grant2082016)a joint project of Beijing Municipal Education Commission(China)
基金Project supported by Japan Society for the Promotion of Science （JSPS）
文摘UV-Vis spectroscopy was used to directly determine the concentration of Eu（ Ⅱ） during electroreduction of Eu （ Ⅲ ） in hydrochloric acid medium. Electroreduction was carried out in a flow type electrolyzer with glassy carbon cathode at the constant potential of - 800 mV vs. Ag/AgCl. The effects of oxygen and concentration of hydrochloric acid on the system were investigated. For 0.01 mol· L^-1 hydrochloric acid, calibration curves for Eu （Ⅱ） absorption bands at 248 and 320 nm were constructed. Molar absorption coefficients were estimated to be 2016 and 648 L· mol^-1·cm^-1, respectively. The absorbance strongly decreased with decrease in pH of the solution, whereas concentration of chloride had only a negligible effect.
基金Supported by the National Natural Science Foundation of China(No. 90201032) and the Postdoctoral Fund of Dalian Nationali-ties University(No. 20056110)
文摘Nanocrystals and powders of KMgF3 doped with Eu^2＋ were synthesized by the microemulsion method and the selvothermal process, respectively. The emission and excitation spectra of KMgF3： Eu^2＋ phosphors were measured and compared with those of the samples synthesized through a solid state reaction, Bridgman-Stockbarger method, and mild hydrothermal technique. The KMgF3： Eu^2＋ samples synthesized by means of the microemulsion method and the solvothermal process show only a sharp emission peak located at 360 nm in the emission spectra, which arises from the f→f（ ^6P7/2→^8S7/2 ） transition of Eu^2＋ The broad emission bands appear at 420 nm, which arises from Eu^2＋←O^2- cannot be observed（ in the mild hydrothermal and single crystal samples, the emission peak at 420 nm besides the emission of Eu^2＋ at 360 nm is observed）. In the excitation spectrum of the KMgF3 ： Eu^2＋ samples synthesized by the microemulsion method and the solvothermal process, the excitation peaks show an intensive blue shift. The blue shift can be attributed to the lower oxygenic content in the KMgF3 ： Eu^2＋ samples synthesized by the microemulsion method and the selvothermal process.
文摘The mononuclear cryptate [Eu(H 3L F)(NO 3)(H 2O)](NO 3) 2 and the heterodinuclear cryptate [EuZnL F(DMF)](ClO 4) 2 were synthesized and characterized. The triplet state energy of the cryptand (H 3L F) was studied by phosphorescence spectrum. The fluorescent properties of Eu(Ⅲ) cryptates in MeOH solution show that the cryptand (H 3L F) can sensitize the Eu(Ⅲ) ion to luminescence and the introduction of the Zn(Ⅱ) ion into the mononuclear Eu(Ⅲ) cryptate resulted in blue shift of three ligand centered bands, increase of molar absorption coefficient and increase of the luminescence intensity of Eu(Ⅲ).
基金Project supported by the National Natural Science Foundation of China
文摘The study of rare earth complexes with crown ether arouses people’s great interest. The previous research work was focused on the complexes with single crown ether. Because of the coordinated actions with metal ions of the two crown ether cycle activities, the bis (crown ether)has better coordination and selectivity than the single crown ether ligands.
文摘There has recently been a great deal of interest in time-resolved fluoroimmunoassay（TRFIA）. Not only the content of proteins, but also the content of haptens canbe detected by TRFIA, e.g. progesterone, digoxin, estrone-3-glucuronide, 17α-hydroxyprogesterone, prostaglandin F<sub>2α</sub>, etc. We describe here a solid-phase, competitiveTRFIA for angiotensin Ⅱ（AⅡ）. AⅡ is an eight-peptide. It plays an important role
