The dominant wavelength range of edge impurity emissions moves from the visible range to the vacuum ultraviolet(VUV)range,as heating power increasing in the Experimental Advanced Superconducting Tokamak(EAST).The meas...The dominant wavelength range of edge impurity emissions moves from the visible range to the vacuum ultraviolet(VUV)range,as heating power increasing in the Experimental Advanced Superconducting Tokamak(EAST).The measurement provided by the existing visible spectroscopies in EAST is not sufficient for impurity transport studies for high-parameters plasmas.Therefore,in this study,a VUV spectroscopy is newly developed to measure edge impurity emissions in EAST.One Seya-Namioka VUV spectrometer(McPherson 234/302)is used in the system,equipped with a concave-corrected holographic grating with groove density of 600 grooves mm-1.Impurity line emissions can be observed in the wavelength range ofλ=50-700 nm,covering VUV,near ultraviolet and visible ranges.The observed vertical range is Z=-350-350 mm.The minimum sampling time can be set to 5 ms under full vertical binning(FVB)mode.VUV spectroscopy has been used to measure the edge impurity emission for the 2019 EAST experimental campaign.Impurity spectra are identified for several impurity species,i.e.,lithium(Li),carbon(C),oxygen(O),and iron(Fe).Several candidates for tungsten(W)lines are also measured but their clear identification is very difficult due to a strong overlap with Fe lines.Time evolutions of impurity carbon emissions of CⅡat 134.5 nm and CⅢat 97.7 nm are analyzed to prove the system capability of time-resolved measurement.The measurements of the VUV spectroscopy are very helpful for edge impurity transport study in the high-parameters plasma in EAST.展开更多
Traditional donor-acceptor type organic luminescent materials usually suffer from unfavorable spectral broadening and fluorescence quenching problems arising from strong inter/intra-chromophore interactions in aggrega...Traditional donor-acceptor type organic luminescent materials usually suffer from unfavorable spectral broadening and fluorescence quenching problems arising from strong inter/intra-chromophore interactions in aggregation state.Here,two ultraviolet carbazole-pyrimidine isomers(named o-DCz-Pm and m-DCz-Pm)with novel aggregation-induced narrowband phenomenon are constructed and systematic investigated by experiments and theoretical simulations.Benefitting from strengthened steric hindrance and multiple noncovalent interactions,the nonradiative decay,vibrational motion,and structural relaxation of singlet state can be effectively suppressed in aggregation state.Consequently,the electroluminescence peak of 397 nm,full width at half maximum of 21 nm and external quantum efficiency of 3.4%are achieved simultaneously in nondoped o-DCz-Pm-based device.This work paves an avenue toward the development of high-performance narrowband nondoped ultraviolet materials and organic light-emitting diodes.展开更多
The twisted aromatics, functional dibenzo[d,f][1,3]dioxepine derivatives were synthesized in high yields from reactions of 5,5＇-dibromo-2,2＇-biphenol with corresponding ketal or ketone compounds under acid catalysis...The twisted aromatics, functional dibenzo[d,f][1,3]dioxepine derivatives were synthesized in high yields from reactions of 5,5＇-dibromo-2,2＇-biphenol with corresponding ketal or ketone compounds under acid catalysis. The structures of these compounds were characterized by ^1H NMR, elemental analysis, UV-Vis absorption spectrum and X-ray diffraction analysis. The conformation of O--C--O bridged biphenyl derivatives with varied substitute groups on 6,6＇-position was studied by X-ray crystallography and force-field simulation. The result of calculations by UNIVERSAL 1.02 force field in Cerius2 package（4.6） indicates that dibenzo[d,f][1,3]dioxepine derivatives show twisted conformations and the twisted angle between the phenyl rings is about 40°, which is accordant with the result from crystal structure determination, though the obtained angles in the crystal of dibenzo[d,f][1,3]dioxepine derivatives with the varied substitute groups on 6,6＇-position are shown to be slightly shifted to 40° owing to intermolecular interactions in crystal stacking. DSC studies exhibit that the substitute groups on 6,6＇-position can induce a large variation of endothermic peaks ranging from 80 to 135 ℃. The conjugated polymers based on dibenzo[d,f][1,3]dioxepine derivatives, which have ultraviolet emitting with a quantum efficiency of 10%, were obtained by Yamamoto coupling.展开更多
A rare-earth free upconversion luminescent material, 10BaF2：NaF, Na3AIF6, is synthesized by a hydrothermal method. The study of fluorescent spectrum indicates that it can convert visible light （550 nm-610 nm） into ...A rare-earth free upconversion luminescent material, 10BaF2：NaF, Na3AIF6, is synthesized by a hydrothermal method. The study of fluorescent spectrum indicates that it can convert visible light （550 nm-610 nm） into ultraviolet light （290 nm 350 nm）, and two emission peaks at 304 nm and 324 nm are observed under the excitation of 583 nm at room temperature. Subsequently, 10BaF2：NaF, Na3AIF6/TiO2 composite photocatalyst is prepared and its catalytic activity is evaluated by the photocatalytic reduction of CO2 under visible light irradiation （λ〉 515 nm）. The results show that 10BaF2：NaF, Na3AIF6/TiO2 is a more effective photocatalyst for CO2 reduction than pure TiO2, their corresponding methanol yields are 179 and 0 μmol/g-cat under the same conditions. Additionally, the mechanism of photocatalytic reduction of CO2 on 10BaF2：NaF, Na3AIF6/TiO2 is proposed.展开更多
Due to narrowband emission and high quantum efficiencies,polycyclic aromatic heterocycles with multi-resonance thermally activated delayed fluorescence(MR-TADF)properties have recently gained considerable attention in...Due to narrowband emission and high quantum efficiencies,polycyclic aromatic heterocycles with multi-resonance thermally activated delayed fluorescence(MR-TADF)properties have recently gained considerable attention in the organic optoelectronic field.Albeit their great promise in the full visible region covering from blue to red,MR-TADF emitters with ultraviolet emission have been rarely reported.Through locking the two ortho-positions of a triphenylamine core by sulfone groups,a simple polycyclic aromatic heterocycle,BTPT,was facilely constructed,exhibiting 368 nm ultraviolet emission with a narrow full width at half maximum(FWHM)of 33 nm.Its neat film exhibited distinct TADF property with a main emission peak at 388 nm.Noteworthily,the enantiomeric crystals of BTPT not only demonstrated significant circularly polarized luminescence(CPL)with large luminescence dissymmetry factor in the 10^(-3) order but also displayed obvious room temperature phosphorescence(RTP).The relationship between this innovative helical unit and unique photophysical properties,including ultraviolet MR-TADF,CPL,and RTP,was reasonably revealed.展开更多
The big blue bump in active galactic nuclei (AGNs) was considered as the thermal radiation from a thin accretion disk. However, the explanation has been challenged by several observational tests in recent years. Tryin...The big blue bump in active galactic nuclei (AGNs) was considered as the thermal radiation from a thin accretion disk. However, the explanation has been challenged by several observational tests in recent years. Trying to overcome the shortage, Barvainis proposed free-free emission mechanism, and successfully fitted the spectrum of AGNs.展开更多
通过以PdCl_2-EDTA为催化剂的Suzuki偶联反应,成功合成具有不同取代基及对称性的对-三联苯化合物,利用核磁共振氢谱(~1 H NMR)和红外光谱(IR)对目标化合物的结构进行表征,利用熔点仪、差示扫描量热仪(DSC)、热重分析仪(TGA)、紫外光谱(...通过以PdCl_2-EDTA为催化剂的Suzuki偶联反应,成功合成具有不同取代基及对称性的对-三联苯化合物,利用核磁共振氢谱(~1 H NMR)和红外光谱(IR)对目标化合物的结构进行表征,利用熔点仪、差示扫描量热仪(DSC)、热重分析仪(TGA)、紫外光谱(UV)和荧光光谱(PL)对目标化合物的光谱性能进行研究.结果表明,对-三联苯化合物具有良好的热稳定性.在对-三联苯上引入—OMe、—COOMe和—CHO基团后,会使对-三联苯的最大吸收峰波长和最大发射峰波长向长波方向移动,对-三联苯化合物结构的对称性对紫外吸收峰有影响,对荧光发射峰无影响.展开更多
基金the National Magnetic Confinement Fusion Science Program of China(Nos.2017YFE0301300 and 2018YFE0301100)National Natural Science Foundation of China(Nos.11805231,11705151)+4 种基金ASIPP Science and Research Grant(No.DSJJ-17-03)Key Program of Research and Development of Hefei Science Center(No.2017HSC-KPRD002)Anhui Provincial Natural Sci-ence Foundation(Nos.1808085QA14 and 1908085J01)Instrument Developing Project of the Chinese Academy of Sciences(No.YJKYYQ20180013)Collaborative Innovation Program of Hefei Science Center,CAS(No.2019HSC-CIP005).
文摘The dominant wavelength range of edge impurity emissions moves from the visible range to the vacuum ultraviolet(VUV)range,as heating power increasing in the Experimental Advanced Superconducting Tokamak(EAST).The measurement provided by the existing visible spectroscopies in EAST is not sufficient for impurity transport studies for high-parameters plasmas.Therefore,in this study,a VUV spectroscopy is newly developed to measure edge impurity emissions in EAST.One Seya-Namioka VUV spectrometer(McPherson 234/302)is used in the system,equipped with a concave-corrected holographic grating with groove density of 600 grooves mm-1.Impurity line emissions can be observed in the wavelength range ofλ=50-700 nm,covering VUV,near ultraviolet and visible ranges.The observed vertical range is Z=-350-350 mm.The minimum sampling time can be set to 5 ms under full vertical binning(FVB)mode.VUV spectroscopy has been used to measure the edge impurity emission for the 2019 EAST experimental campaign.Impurity spectra are identified for several impurity species,i.e.,lithium(Li),carbon(C),oxygen(O),and iron(Fe).Several candidates for tungsten(W)lines are also measured but their clear identification is very difficult due to a strong overlap with Fe lines.Time evolutions of impurity carbon emissions of CⅡat 134.5 nm and CⅢat 97.7 nm are analyzed to prove the system capability of time-resolved measurement.The measurements of the VUV spectroscopy are very helpful for edge impurity transport study in the high-parameters plasma in EAST.
基金National Natural Science Foundation of China,Grant/Award Numbers:52002804,52103220,52103017,22022501Shandong Provincial Natural Science Foundation,Grant/Award Numbers:ZR2023QE078,ZR2022ZD37,ZR2019ZD50Natural Science Foundation of Qingdao Municipality,Grant/Award Number:23-2-1-75-zyyd-jch。
文摘Traditional donor-acceptor type organic luminescent materials usually suffer from unfavorable spectral broadening and fluorescence quenching problems arising from strong inter/intra-chromophore interactions in aggregation state.Here,two ultraviolet carbazole-pyrimidine isomers(named o-DCz-Pm and m-DCz-Pm)with novel aggregation-induced narrowband phenomenon are constructed and systematic investigated by experiments and theoretical simulations.Benefitting from strengthened steric hindrance and multiple noncovalent interactions,the nonradiative decay,vibrational motion,and structural relaxation of singlet state can be effectively suppressed in aggregation state.Consequently,the electroluminescence peak of 397 nm,full width at half maximum of 21 nm and external quantum efficiency of 3.4%are achieved simultaneously in nondoped o-DCz-Pm-based device.This work paves an avenue toward the development of high-performance narrowband nondoped ultraviolet materials and organic light-emitting diodes.
基金Supported by the National Natural Science Foundation of China(Nos.20125421 and 90101026)the Ministry of Science and Technology of China(No.2002CB6134003)
文摘The twisted aromatics, functional dibenzo[d,f][1,3]dioxepine derivatives were synthesized in high yields from reactions of 5,5＇-dibromo-2,2＇-biphenol with corresponding ketal or ketone compounds under acid catalysis. The structures of these compounds were characterized by ^1H NMR, elemental analysis, UV-Vis absorption spectrum and X-ray diffraction analysis. The conformation of O--C--O bridged biphenyl derivatives with varied substitute groups on 6,6＇-position was studied by X-ray crystallography and force-field simulation. The result of calculations by UNIVERSAL 1.02 force field in Cerius2 package（4.6） indicates that dibenzo[d,f][1,3]dioxepine derivatives show twisted conformations and the twisted angle between the phenyl rings is about 40°, which is accordant with the result from crystal structure determination, though the obtained angles in the crystal of dibenzo[d,f][1,3]dioxepine derivatives with the varied substitute groups on 6,6＇-position are shown to be slightly shifted to 40° owing to intermolecular interactions in crystal stacking. DSC studies exhibit that the substitute groups on 6,6＇-position can induce a large variation of endothermic peaks ranging from 80 to 135 ℃. The conjugated polymers based on dibenzo[d,f][1,3]dioxepine derivatives, which have ultraviolet emitting with a quantum efficiency of 10%, were obtained by Yamamoto coupling.
基金supported by the National Natural Science Foundation of China (Grant No. 20876125)the Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20096101110013)the Northwest University Graduate Interdisciplinary Funds, China (Grant Nos. 09YJC24 and 09YJC27)
文摘A rare-earth free upconversion luminescent material, 10BaF2：NaF, Na3AIF6, is synthesized by a hydrothermal method. The study of fluorescent spectrum indicates that it can convert visible light （550 nm-610 nm） into ultraviolet light （290 nm 350 nm）, and two emission peaks at 304 nm and 324 nm are observed under the excitation of 583 nm at room temperature. Subsequently, 10BaF2：NaF, Na3AIF6/TiO2 composite photocatalyst is prepared and its catalytic activity is evaluated by the photocatalytic reduction of CO2 under visible light irradiation （λ〉 515 nm）. The results show that 10BaF2：NaF, Na3AIF6/TiO2 is a more effective photocatalyst for CO2 reduction than pure TiO2, their corresponding methanol yields are 179 and 0 μmol/g-cat under the same conditions. Additionally, the mechanism of photocatalytic reduction of CO2 on 10BaF2：NaF, Na3AIF6/TiO2 is proposed.
基金supported by the National Natural Science Foundation of China(52022071,52130308,91833304)the Fundamental Research Funds for the Central Universities(2042021kf1060)Shenzhen Science and Technology Program(ZDSYS20210623091813040,JCYJ20190808151209557)。
文摘Due to narrowband emission and high quantum efficiencies,polycyclic aromatic heterocycles with multi-resonance thermally activated delayed fluorescence(MR-TADF)properties have recently gained considerable attention in the organic optoelectronic field.Albeit their great promise in the full visible region covering from blue to red,MR-TADF emitters with ultraviolet emission have been rarely reported.Through locking the two ortho-positions of a triphenylamine core by sulfone groups,a simple polycyclic aromatic heterocycle,BTPT,was facilely constructed,exhibiting 368 nm ultraviolet emission with a narrow full width at half maximum(FWHM)of 33 nm.Its neat film exhibited distinct TADF property with a main emission peak at 388 nm.Noteworthily,the enantiomeric crystals of BTPT not only demonstrated significant circularly polarized luminescence(CPL)with large luminescence dissymmetry factor in the 10^(-3) order but also displayed obvious room temperature phosphorescence(RTP).The relationship between this innovative helical unit and unique photophysical properties,including ultraviolet MR-TADF,CPL,and RTP,was reasonably revealed.
基金Project supported by the National Natural Science Foundation of China
文摘The big blue bump in active galactic nuclei (AGNs) was considered as the thermal radiation from a thin accretion disk. However, the explanation has been challenged by several observational tests in recent years. Trying to overcome the shortage, Barvainis proposed free-free emission mechanism, and successfully fitted the spectrum of AGNs.
文摘通过以PdCl_2-EDTA为催化剂的Suzuki偶联反应,成功合成具有不同取代基及对称性的对-三联苯化合物,利用核磁共振氢谱(~1 H NMR)和红外光谱(IR)对目标化合物的结构进行表征,利用熔点仪、差示扫描量热仪(DSC)、热重分析仪(TGA)、紫外光谱(UV)和荧光光谱(PL)对目标化合物的光谱性能进行研究.结果表明,对-三联苯化合物具有良好的热稳定性.在对-三联苯上引入—OMe、—COOMe和—CHO基团后,会使对-三联苯的最大吸收峰波长和最大发射峰波长向长波方向移动,对-三联苯化合物结构的对称性对紫外吸收峰有影响,对荧光发射峰无影响.
