Near-monodisperse NaYF4：Yb/Er nanoparticles（NPs） with controlled size, phases（α,β） and shapes（sphere, and hexagonal plate） were synthesized by adjusting the NaF to RE（RE = Y, Yb, Er） ratios, the reaction te...Near-monodisperse NaYF4：Yb/Er nanoparticles（NPs） with controlled size, phases（α,β） and shapes（sphere, and hexagonal plate） were synthesized by adjusting the NaF to RE（RE = Y, Yb, Er） ratios, the reaction temperature and time in the hot surfactant solutions（oleic acid, 1-octadecene） from the improved one-pot thermal decomposition metal trifluoroacetate, and the precursors were prepared via hydrothermal route. The growth kinetics of β-NaYF4 NPs includes several stages： nucleation, growth of aNaYF4, Ostwald ripening, size shrinkage and growth. The results prove that the temperatures are preferred to the phase transformation compared with the NaF content when other experimental conditions are unchanged. Our work will further facilitate the comprehension of the nucleation and growth mechanisms of the NPs, and provide guidance for their controlled synthesis.展开更多
We investigate the influences of the-applied-field phases and amplitudes on the coherent population trapping behavior in superconducting quantum circuits. Based on the interactions of the microwave fields with a singl...We investigate the influences of the-applied-field phases and amplitudes on the coherent population trapping behavior in superconducting quantum circuits. Based on the interactions of the microwave fields with a single A-type three-level fluxonium qubit, the coherent population trapping could be obtainable and it is very sensitive to the relative phase and amplitudes of the applied fields. When the relative phase is tuned to 0 or π, the maximal atomic coherence is present and coherent population trapping occurs. While for the choice of π/2, the atomic coherence becomes weak. Meanwhile, for the fixed relative phase π/2, the value of coherence would decrease with the increase of Rabi frequency of the external field coupled with two lower levels. The responsible physical mechanism is quantum interference induced by the control fields, which is indicated in the dressed-state representation. The microwave coherent phenomenon is present in our scheme, which will have potential applications in optical communication and nonlinear optics in solid-state devices.展开更多
Constrained by the characteristics of neutral sec- tions (NS) and traditional vacuum circuit breakers, previous phase-controlled strategies have a long power supply dead time, it is difficult to realize a continuous p...Constrained by the characteristics of neutral sec- tions (NS) and traditional vacuum circuit breakers, previous phase-controlled strategies have a long power supply dead time, it is difficult to realize a continuous power supply to the auxiliary power system. The dead time can be reduced by using the ground automatic convert method, hybrid phase-controlled technologies can in theory completely eliminate inrush currents. In this paper, a new system based on hybrid phase-controlled switches is described and termed ground-switching passing neutral section system (GPNSS). The principle for restraining inrush currents is analyzed and strategies are carried out with the dead time limited to 5 ms. The characteristics of the vacuum circuit breaker are illustrated and the closing time window of the transformer is quantified. Through the use of mechanical switches and power electronics, the auxiliary power system may be continuously pow- ered. The prototype system is implemented and experimentally tested in the laboratory.展开更多
Large-scale production of unconventional phase-controlled telluride catalysts in a simple and fast manner still poses a great challenge.Herein,we develop a superfast tellurizing synthesis method that can quickly prepa...Large-scale production of unconventional phase-controlled telluride catalysts in a simple and fast manner still poses a great challenge.Herein,we develop a superfast tellurizing synthesis method that can quickly prepare unconventional phase-controlled palladium telluride nanoparticles(Pd-Te NPs)on carbon nanotubes(CNTs)(i.e.,PdTe/CNT,Pd_(20)Te_(7)/CNT)in 60 s.By merely tuning the mass of the tellurium precursors under the same conditions,fine(about 5.5 nm)and high-yield(about 90%)hexagonal structured PdTe/CNT and rhombohedral structured Pd_(20)Te_(7)/CNT can be precisely synthesized.The hexagonal structured PdTe/CNT exhibits excellent performance for glycerol oxidation reaction(GOR)and ethylene glycol oxidation reaction(EGOR).Specifically,the highest current density for GOR is 2.72 A mgPd^(-1),which is 1.9-fold higher than that of rhombohedral structured Pd_(20)Te_(7)/CNT,and 2.8-fold higher than that of Pd/CNT.It also outperforms most catalysts reported in GOR.Meanwhile,the specific activity for EGOR is 3.65 A mgPd^(-1),which is 2.1 and 3.9 times higher than those of rhombohedral structured Pd_(20)Te_(7)/CNT and Pd/CNT.We hope that this work can provide guidance for the preparation of crystalline phase-controlled telluride catalysts via new tellurization and inspire the application of crystalline phasecontrolled materials.展开更多
We report a novel stimulated Raman scattering(SRS)microscopy technique featuring phase-controlled light focusing and aberration corrections for rapid,deep tissue 3D chemical imaging with subcellular resolution.To acco...We report a novel stimulated Raman scattering(SRS)microscopy technique featuring phase-controlled light focusing and aberration corrections for rapid,deep tissue 3D chemical imaging with subcellular resolution.To accomplish phasecontrolled SRS(PC-SRS),we utilize a single spatial light modulator to electronically tune the axial positioning of both the shortened-length Bessel pump and the focused Gaussian Stokes beams,enabling z-scanning-free optical sectioning in the sample.By incorporating Zernike polynomials into the phase patterns,we simultaneously correct the system aberrations at two separate wavelengths(~240 nm difference),achieving a~3-fold enhancement in signal-to-noise ratio over the uncorrected imaging system.PC-SRS provides>2-fold improvement in imaging depth in various samples(e.g.,polystyrene bead phantoms,porcine brain tissue)as well as achieves SRS 3D imaging speed of~13 Hz per volume for real-time monitoring of Brownian motion of polymer beads in water,superior to conventional point-scanning SRS 3D imaging.We further utilize PC-SRS to observe the metabolic activities of the entire tumor liver in living zebrafish in cellsilent region,unraveling the upregulated metabolism in liver tumor compared to normal liver.This work shows that PCSRS provides unprecedented insights into morpho-chemistry,metabolic and dynamic functioning of live cells and tissue in real-time at the subcellular level.展开更多
基金Project supported by the National Natural Science Foundation of China(2126016)the Science and Technology Innovation Guidance Project,Inner Mongolia,China(000-21090179)+2 种基金the Talents Project Inner Mongolia(CYYC:5026)the Opened Fund of the State Key Laboratory on integrated Optoelectronics(China IOSKL2013KF08)the Graduate Student Scientific Research Foundation of Inner Mongolia(S20161013505)
文摘Near-monodisperse NaYF4：Yb/Er nanoparticles（NPs） with controlled size, phases（α,β） and shapes（sphere, and hexagonal plate） were synthesized by adjusting the NaF to RE（RE = Y, Yb, Er） ratios, the reaction temperature and time in the hot surfactant solutions（oleic acid, 1-octadecene） from the improved one-pot thermal decomposition metal trifluoroacetate, and the precursors were prepared via hydrothermal route. The growth kinetics of β-NaYF4 NPs includes several stages： nucleation, growth of aNaYF4, Ostwald ripening, size shrinkage and growth. The results prove that the temperatures are preferred to the phase transformation compared with the NaF content when other experimental conditions are unchanged. Our work will further facilitate the comprehension of the nucleation and growth mechanisms of the NPs, and provide guidance for their controlled synthesis.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11165008 and 11365009)the Foundation of Young Scientist of Jiangxi Province,China(Grant No.20142BCB23011)the Scientific Research Foundation of Jiangxi Provincial Department of Education(Grant No.GJJ13348)
文摘We investigate the influences of the-applied-field phases and amplitudes on the coherent population trapping behavior in superconducting quantum circuits. Based on the interactions of the microwave fields with a single A-type three-level fluxonium qubit, the coherent population trapping could be obtainable and it is very sensitive to the relative phase and amplitudes of the applied fields. When the relative phase is tuned to 0 or π, the maximal atomic coherence is present and coherent population trapping occurs. While for the choice of π/2, the atomic coherence becomes weak. Meanwhile, for the fixed relative phase π/2, the value of coherence would decrease with the increase of Rabi frequency of the external field coupled with two lower levels. The responsible physical mechanism is quantum interference induced by the control fields, which is indicated in the dressed-state representation. The microwave coherent phenomenon is present in our scheme, which will have potential applications in optical communication and nonlinear optics in solid-state devices.
文摘Constrained by the characteristics of neutral sec- tions (NS) and traditional vacuum circuit breakers, previous phase-controlled strategies have a long power supply dead time, it is difficult to realize a continuous power supply to the auxiliary power system. The dead time can be reduced by using the ground automatic convert method, hybrid phase-controlled technologies can in theory completely eliminate inrush currents. In this paper, a new system based on hybrid phase-controlled switches is described and termed ground-switching passing neutral section system (GPNSS). The principle for restraining inrush currents is analyzed and strategies are carried out with the dead time limited to 5 ms. The characteristics of the vacuum circuit breaker are illustrated and the closing time window of the transformer is quantified. Through the use of mechanical switches and power electronics, the auxiliary power system may be continuously pow- ered. The prototype system is implemented and experimentally tested in the laboratory.
基金supported by the National Natural Science Foundation of China(51772162,22001143,and 52072197)the Youth Innovation and Technology Foundation of Shandong Higher Education Institutions,China(2019KJC004)+4 种基金the Outstanding Youth Foundation of Shandong Province,China(ZR2019JQ14)Taishan Scholar Young Talent Program(tsqn201909114 and tsqn201909123)the Natural Science Foundation of Shandong Province(ZR2020YQ34)the Major Scientific and Technological Innovation Project(2019JZZY020405)the Major Basic Research Program of Natural Science Foundation of Shandong Province(ZR2020ZD09)。
文摘Large-scale production of unconventional phase-controlled telluride catalysts in a simple and fast manner still poses a great challenge.Herein,we develop a superfast tellurizing synthesis method that can quickly prepare unconventional phase-controlled palladium telluride nanoparticles(Pd-Te NPs)on carbon nanotubes(CNTs)(i.e.,PdTe/CNT,Pd_(20)Te_(7)/CNT)in 60 s.By merely tuning the mass of the tellurium precursors under the same conditions,fine(about 5.5 nm)and high-yield(about 90%)hexagonal structured PdTe/CNT and rhombohedral structured Pd_(20)Te_(7)/CNT can be precisely synthesized.The hexagonal structured PdTe/CNT exhibits excellent performance for glycerol oxidation reaction(GOR)and ethylene glycol oxidation reaction(EGOR).Specifically,the highest current density for GOR is 2.72 A mgPd^(-1),which is 1.9-fold higher than that of rhombohedral structured Pd_(20)Te_(7)/CNT,and 2.8-fold higher than that of Pd/CNT.It also outperforms most catalysts reported in GOR.Meanwhile,the specific activity for EGOR is 3.65 A mgPd^(-1),which is 2.1 and 3.9 times higher than those of rhombohedral structured Pd_(20)Te_(7)/CNT and Pd/CNT.We hope that this work can provide guidance for the preparation of crystalline phase-controlled telluride catalysts via new tellurization and inspire the application of crystalline phasecontrolled materials.
基金supported by the Academic Research Fund(AcRF)from the Ministry of Education(MOE)(Tier 2(A-8000117-01-00)Tier 1(R397-000-334-114,R397-000-371-114,and R397-000-378-114)2024 Tsinghua-NUS Joint Research Initiative Fund,and the National Medical Research Council(NMRC)(A-0009502-01-00,and A-8001143-00-00),Singapore.
文摘We report a novel stimulated Raman scattering(SRS)microscopy technique featuring phase-controlled light focusing and aberration corrections for rapid,deep tissue 3D chemical imaging with subcellular resolution.To accomplish phasecontrolled SRS(PC-SRS),we utilize a single spatial light modulator to electronically tune the axial positioning of both the shortened-length Bessel pump and the focused Gaussian Stokes beams,enabling z-scanning-free optical sectioning in the sample.By incorporating Zernike polynomials into the phase patterns,we simultaneously correct the system aberrations at two separate wavelengths(~240 nm difference),achieving a~3-fold enhancement in signal-to-noise ratio over the uncorrected imaging system.PC-SRS provides>2-fold improvement in imaging depth in various samples(e.g.,polystyrene bead phantoms,porcine brain tissue)as well as achieves SRS 3D imaging speed of~13 Hz per volume for real-time monitoring of Brownian motion of polymer beads in water,superior to conventional point-scanning SRS 3D imaging.We further utilize PC-SRS to observe the metabolic activities of the entire tumor liver in living zebrafish in cellsilent region,unraveling the upregulated metabolism in liver tumor compared to normal liver.This work shows that PCSRS provides unprecedented insights into morpho-chemistry,metabolic and dynamic functioning of live cells and tissue in real-time at the subcellular level.
