Gd_2O_3∶Er nanoparticles were prepared by a simple sol-gel method. The structure properties of Gd_2O_3∶Er were studied by X-ray diffraction, transmission electron microscopy, Raman spectroscopy and Fourier transform...Gd_2O_3∶Er nanoparticles were prepared by a simple sol-gel method. The structure properties of Gd_2O_3∶Er were studied by X-ray diffraction, transmission electron microscopy, Raman spectroscopy and Fourier transform infrared spectroscopy. The visible up-converted luminescence spectra of Er^(3+) were investigated under excitation to (()~4I_(9/2)) level by 785 nm laser. Laser power, Er^(3+) ion concentration and temperature dependences of the upconverted emissions were investigated to understand the upconversion mechanisms. Excited state absorption and energy transfer process are discussed as the possible mechanisms for the upconversion.展开更多
Multifunctional luminescent materials are attracting attention nowadays.In this work,monoclinic Gd_(2)O_(3):Er^(3+)nanoparticles,which possess up-conversion luminescence and down-conversion luminescence properties,wer...Multifunctional luminescent materials are attracting attention nowadays.In this work,monoclinic Gd_(2)O_(3):Er^(3+)nanoparticles,which possess up-conversion luminescence and down-conversion luminescence properties,were successfully synthesized by laser ablation in liquid(LAL)technique.Up-conversion luminescence and down-conversion luminescence of monoclinic Gd_(2)O_(3):Er^(3+)nanoparticles were got under the excitation of 980 nm and 379 nm,respectively.In addition,tunable luminescence was got.Furthermore,the cytotoxicity of the nanoparticles is low and the fluorescence of the nanoparticles in cell is also strong enough.The results indicate that the Gd_(2)O_(3):Er^(3+)nanoparticles synthesized by LAL technique are promising candidates for bio-imaging or other fields that require controllable fluorescence.展开更多
Y_(1-x)Ho_xBa_2Cu_3O_(7-δ)(0<x<1) sinsle crystal thin films oriented with the caxis perpendicular to the sur-face were grown by DC magnetron sputtering technique. Target was pieced together with half of YBa_2Cu...Y_(1-x)Ho_xBa_2Cu_3O_(7-δ)(0<x<1) sinsle crystal thin films oriented with the caxis perpendicular to the sur-face were grown by DC magnetron sputtering technique. Target was pieced together with half of YBa_2Cu_3O_(7-δ)(YBCO) and half of HoBa_2Cu_3O_(7-δ)(HBCO) superconducting materials. As the distance between HBCO targetmaterial and substrate is varied , the Ho content in material is changed respectively. When the content of Ho is0. 7 (atom ratio) , the T_c>83K.展开更多
In an effort to improve the performance of superconductors in the field and high temperatures it is important to study the superconducting mechanism. For this reason, the cation substitution can be conducted. One of t...In an effort to improve the performance of superconductors in the field and high temperatures it is important to study the superconducting mechanism. For this reason, the cation substitution can be conducted. One of the high Tc superconductors Gd1Ba2Cu3O7−δ phase with Sr substitution has been synthesized, i.e. Gd1(Ba2−xSrx)Cu3O7−δ compound. The sample was synthesized by using a solid-state reaction method with a wet mixing, sintered for 12 hours at temperature 900°C. The synthesis results are characterized by using XRD. The results of Match-3 software analysis showed high (higher 85%) Gd1Ba2Cu3O7−δ phase was formed. The Sr substitution causes changes to the structure, i.e. the lattice parameters a, b and c, where the orthorhombicity tends to decrease with increasing Sr content. Refinement results show that based on the oxygen occupancy, the total oxygen content tends to increase.展开更多
The electron momentum distribution of 3σ_u orbital of carbon dioxide has been measured at high momentum resolution. Through comparation between experimental and theoretical results, the calculation by DFT-B3LYP metho...The electron momentum distribution of 3σ_u orbital of carbon dioxide has been measured at high momentum resolution. Through comparation between experimental and theoretical results, the calculation by DFT-B3LYP method using 6- 311 + +G basis set is more agreement with the experirnental data than other calculations.展开更多
采用传统的高温固相法制备一种新型的红色荧光粉Ba_(6)Gd_(2)Ti_(4)O_(17):Sm^(3+),并通过X射线衍射(X-ray diffraction,XRD)、扫描电子显微镜(scanning electron microscope,SEM)、荧光(photoluminescence,PL)光谱及色坐标表征系列样...采用传统的高温固相法制备一种新型的红色荧光粉Ba_(6)Gd_(2)Ti_(4)O_(17):Sm^(3+),并通过X射线衍射(X-ray diffraction,XRD)、扫描电子显微镜(scanning electron microscope,SEM)、荧光(photoluminescence,PL)光谱及色坐标表征系列样品的物相、形貌和发光性能.PL光谱表明该荧光粉可以被近紫外光有效激发,在407 nm近紫外光激发下,发射光谱由四个发射峰组成,最强发射峰位于616 nm处,归结为Sm^(3+)的^(4)G_(5/2)→^(6)H_(7/2)跃迁.随着Sm^(3+)掺杂量的增加,荧光粉的发光强度先增大后减小,最佳掺杂比例(物质的量分数)为3%.系列掺杂比例荧光粉的色坐标基本不变,均位于红光区.研究结果表明,该荧光粉是一种具有应用前景的新型白光发光二极管(light-emitting diode,LED)用红色荧光粉.展开更多
Environmental sediments mainly consisting of CaO–MgO–Al_(2)O_(3)–SiO_(2)(CMAS)corrosion are a serious threat to thermal barrier coatings(TBCs),in which Fe element is usually ignored.Gd_(2)Zr_(2)O_(7)TBCs are famous...Environmental sediments mainly consisting of CaO–MgO–Al_(2)O_(3)–SiO_(2)(CMAS)corrosion are a serious threat to thermal barrier coatings(TBCs),in which Fe element is usually ignored.Gd_(2)Zr_(2)O_(7)TBCs are famous for their excellent CMAS resistance.In this study,the characteristics of Fe-containing environmental sediments(CMAS-Fe)and their corrosiveness to Gd_(2)Zr_(2)O_(7)coatings were investigated.Four types of CMAS-Fe glass with different Fe contents were fabricated.Their melting points were measured to be 1322–1344℃,and the high-temperature viscosity showed a decreasing trend with increasing Fe contents.The corrosion behavior of four types of CMAS-Fe to Gd_(2)Zr_(2)O_(7)coatings at 1350℃was investigated.At the initial corrosion stage(0.1 h),anorthite was precipitated in CMAS-Fe with a high Ca:Si ratio,while Fe-garnet was formed in the melt with the highest Fe content.Prolonging the corrosion time resulted in the formation of a reaction layer,which exhibited an interpenetrating network composed of Gd-oxyapatite,ZrO_(2),and residual CMAS-Fe.Some spinel was precipitated within the reaction layer.After 1 h or even longer time,the reaction layers tended to be stable and compact,which had comparable hardness and fracture toughness to those of Gd_(2)Zr_(2)O_(7)coatings.Under the cyclic CMAS-Fe attack,the residual CMAS-Fe in the interpenetrating network provided a pathway for the redeposited CMAS-Fe infiltration,resulting in the continuous growth of the reaction layer.As a result,the Gd_(2)Zr_(2)O_(7)coatings had a large consumption in the thickness,degrading the coating performance.Therefore,the Gd_(2)Zr_(2)O_(7)coatings exhibit unsatisfactory corrosion resistance to CMAS-Fe attack.展开更多
Electron-trapping materials,due to their exceptional ability of energy storage and controllable photon release under external stimulation,have attracted considerable attention in the field of optical information stora...Electron-trapping materials,due to their exceptional ability of energy storage and controllable photon release under external stimulation,have attracted considerable attention in the field of optical information storage(OIS).In this work,Gd_(3)Al_(3)Ga_(2)O_(12):Ce^(3+), Yb^(3+)fluorescent ceramics,were developed using air and vacuum sintering technology.By co-doping Ce^(3+)and Yb^(3+),the trap density was significantly increased by 7.5 times compared to samples containing only Ce^(3+).Vacuum annealing further enhanced trap density by 1.6 times compared to samples sintered solely in air,while generating deep traps(1.44 eV),making Gd_(3)Al_(3)Ga_(2)O_(12):Ce^(3+), Yb^(3+) an excellent OIS medium.This work is expected to facilitate the development of OIS materials.展开更多
文摘Gd_2O_3∶Er nanoparticles were prepared by a simple sol-gel method. The structure properties of Gd_2O_3∶Er were studied by X-ray diffraction, transmission electron microscopy, Raman spectroscopy and Fourier transform infrared spectroscopy. The visible up-converted luminescence spectra of Er^(3+) were investigated under excitation to (()~4I_(9/2)) level by 785 nm laser. Laser power, Er^(3+) ion concentration and temperature dependences of the upconverted emissions were investigated to understand the upconversion mechanisms. Excited state absorption and energy transfer process are discussed as the possible mechanisms for the upconversion.
文摘Multifunctional luminescent materials are attracting attention nowadays.In this work,monoclinic Gd_(2)O_(3):Er^(3+)nanoparticles,which possess up-conversion luminescence and down-conversion luminescence properties,were successfully synthesized by laser ablation in liquid(LAL)technique.Up-conversion luminescence and down-conversion luminescence of monoclinic Gd_(2)O_(3):Er^(3+)nanoparticles were got under the excitation of 980 nm and 379 nm,respectively.In addition,tunable luminescence was got.Furthermore,the cytotoxicity of the nanoparticles is low and the fluorescence of the nanoparticles in cell is also strong enough.The results indicate that the Gd_(2)O_(3):Er^(3+)nanoparticles synthesized by LAL technique are promising candidates for bio-imaging or other fields that require controllable fluorescence.
文摘Y_(1-x)Ho_xBa_2Cu_3O_(7-δ)(0<x<1) sinsle crystal thin films oriented with the caxis perpendicular to the sur-face were grown by DC magnetron sputtering technique. Target was pieced together with half of YBa_2Cu_3O_(7-δ)(YBCO) and half of HoBa_2Cu_3O_(7-δ)(HBCO) superconducting materials. As the distance between HBCO targetmaterial and substrate is varied , the Ho content in material is changed respectively. When the content of Ho is0. 7 (atom ratio) , the T_c>83K.
基金This report is part of the fundamental research report with contract No.486 127/UN14.2/PNL.01.03.00/2016.
文摘In an effort to improve the performance of superconductors in the field and high temperatures it is important to study the superconducting mechanism. For this reason, the cation substitution can be conducted. One of the high Tc superconductors Gd1Ba2Cu3O7−δ phase with Sr substitution has been synthesized, i.e. Gd1(Ba2−xSrx)Cu3O7−δ compound. The sample was synthesized by using a solid-state reaction method with a wet mixing, sintered for 12 hours at temperature 900°C. The synthesis results are characterized by using XRD. The results of Match-3 software analysis showed high (higher 85%) Gd1Ba2Cu3O7−δ phase was formed. The Sr substitution causes changes to the structure, i.e. the lattice parameters a, b and c, where the orthorhombicity tends to decrease with increasing Sr content. Refinement results show that based on the oxygen occupancy, the total oxygen content tends to increase.
文摘The electron momentum distribution of 3σ_u orbital of carbon dioxide has been measured at high momentum resolution. Through comparation between experimental and theoretical results, the calculation by DFT-B3LYP method using 6- 311 + +G basis set is more agreement with the experirnental data than other calculations.
基金the National Natural Science Foundation of China(Grant No.52272070)National Science and Technology Major Project(Grant No.J2022-VI-0009-0040).
文摘Environmental sediments mainly consisting of CaO–MgO–Al_(2)O_(3)–SiO_(2)(CMAS)corrosion are a serious threat to thermal barrier coatings(TBCs),in which Fe element is usually ignored.Gd_(2)Zr_(2)O_(7)TBCs are famous for their excellent CMAS resistance.In this study,the characteristics of Fe-containing environmental sediments(CMAS-Fe)and their corrosiveness to Gd_(2)Zr_(2)O_(7)coatings were investigated.Four types of CMAS-Fe glass with different Fe contents were fabricated.Their melting points were measured to be 1322–1344℃,and the high-temperature viscosity showed a decreasing trend with increasing Fe contents.The corrosion behavior of four types of CMAS-Fe to Gd_(2)Zr_(2)O_(7)coatings at 1350℃was investigated.At the initial corrosion stage(0.1 h),anorthite was precipitated in CMAS-Fe with a high Ca:Si ratio,while Fe-garnet was formed in the melt with the highest Fe content.Prolonging the corrosion time resulted in the formation of a reaction layer,which exhibited an interpenetrating network composed of Gd-oxyapatite,ZrO_(2),and residual CMAS-Fe.Some spinel was precipitated within the reaction layer.After 1 h or even longer time,the reaction layers tended to be stable and compact,which had comparable hardness and fracture toughness to those of Gd_(2)Zr_(2)O_(7)coatings.Under the cyclic CMAS-Fe attack,the residual CMAS-Fe in the interpenetrating network provided a pathway for the redeposited CMAS-Fe infiltration,resulting in the continuous growth of the reaction layer.As a result,the Gd_(2)Zr_(2)O_(7)coatings had a large consumption in the thickness,degrading the coating performance.Therefore,the Gd_(2)Zr_(2)O_(7)coatings exhibit unsatisfactory corrosion resistance to CMAS-Fe attack.
基金supported by the National Key R&D Program of China(Nos.2021YFB2802000 and 2022YFA1204300)the Shanghai Municipal Science and Technology Commission Innovation Action Plan(No.18DZ1100400)+4 种基金the National Natural Science Foundation of China(Nos.52221001,62090035,62175061,and U19A2090)the Key Program of Science and Technology Department of Hunan Province(Nos.2019XK2001 and 2020XK2001)the Key Research and Development Plan of Hunan Province(No.2023GK2012)the Open Project of Key Laboratory of Nanodevices and Applications,Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences(No.22ZS01)the Natural Science Foundation of Hunan Province(No.2022JJ30167).
文摘Electron-trapping materials,due to their exceptional ability of energy storage and controllable photon release under external stimulation,have attracted considerable attention in the field of optical information storage(OIS).In this work,Gd_(3)Al_(3)Ga_(2)O_(12):Ce^(3+), Yb^(3+)fluorescent ceramics,were developed using air and vacuum sintering technology.By co-doping Ce^(3+)and Yb^(3+),the trap density was significantly increased by 7.5 times compared to samples containing only Ce^(3+).Vacuum annealing further enhanced trap density by 1.6 times compared to samples sintered solely in air,while generating deep traps(1.44 eV),making Gd_(3)Al_(3)Ga_(2)O_(12):Ce^(3+), Yb^(3+) an excellent OIS medium.This work is expected to facilitate the development of OIS materials.
