An accurate and reasonable technique combining direct absorption spectroscopy and laser-induced fluorescence（LIF）methods is developed to quantitatively measure the concentrations of hydroxyl in CH;/air flat laminar ...An accurate and reasonable technique combining direct absorption spectroscopy and laser-induced fluorescence（LIF）methods is developed to quantitatively measure the concentrations of hydroxyl in CH;/air flat laminar flame. In our approach, particular attention is paid to the linear laser-induced fluorescence and absorption processes, and experimental details as well. Through measuring the temperature, LIF signal distribution and integrated absorption, spatially absolute OH concentrations profiles are successfully resolved. These experimental results are then compared with the numerical simulation. It is proved that the good quality of the results implies that this method is suitable for calibrating the OH-PLIF measurement in a practical combustor.展开更多
A combined detection system involving simultaneous LIF and contacfless-conductometric measurements at the same place of the microfluidic chip was described. The LIF measurement was designed according to the confocal p...A combined detection system involving simultaneous LIF and contacfless-conductometric measurements at the same place of the microfluidic chip was described. The LIF measurement was designed according to the confocal principle and a moveable contactless-conduetivity detector was used in C^4D. Both measurements were mutually independent and advantageous in analyses of mixtures. Various experimental parameters affecting the response were examined and optimized. The performances were demonstrated by simultaneous detection of Rhodamine B. And the results showed that the combined detection system could be used sensitively and reliably.展开更多
Magnesium monofluoride(MgF)is proposed as an ideal candidate radical for direct laser cooling.Here,the rotationally resolved laser spectra of MgF for the A^(2)Π-X^(2)∑^(+) electronic transition system were recorded ...Magnesium monofluoride(MgF)is proposed as an ideal candidate radical for direct laser cooling.Here,the rotationally resolved laser spectra of MgF for the A^(2)Π-X^(2)∑^(+) electronic transition system were recorded by using laser induced fluorescence technique.The MgF radicals were produced by discharging SF_(6)/Ar gas mixtures between the tips of two magnesium needles in a supersonic jet expansion.We recorded a total of 19 vibrational bands belonging to three sequences of Δv=0,±1 in the region of 348-370 nm.Accurate spectroscopic constants for both X^(2)∑^(+) and A^(2)Π states are determined from rotational analysis of the experimental spectra.Spectroscopic parameters,including the Franck-Condon factors(FCFs),are determined from the experimental results and the Rydberg-Klein-Rees(RKR)calculations.Significant discrepancies between the experimentally measured and RKR-calculated FCFs are found,indicating that the FCFs are nearly independent of the spin-orbit coupling in the A^(2)Π state.Potential energy curves(PECs)and FCFs determined here provide necessary data for the theoretical simulation of the laser-cooling scheme of MgF.展开更多
N-Conjugated antigen was synthesized and polyclonal antibody with high specificity was obtained from immunizing animals. With this polyclonal antibody, a rapid and efficient CEIA-LIF method was developed to determine ...N-Conjugated antigen was synthesized and polyclonal antibody with high specificity was obtained from immunizing animals. With this polyclonal antibody, a rapid and efficient CEIA-LIF method was developed to determine the free morphine in urine of abusers. The detection limit was calculated to be 40 ng/mL. Simulated urine samples were analyzed with good recoveries, which showed the feasibility of its application in specific morphine determination in urine of morphine abusers.展开更多
Dy：Lu2O3 was grown by the float-zone （Fz） method. According to the absorption spectrum, the Judd-Ofelt （JO） parameters Ω2, Ω4, and Ω6 were calculated to be 4.86 × 10-20 cm2, 2.02 × 10-20 cm2, and 1.7...Dy：Lu2O3 was grown by the float-zone （Fz） method. According to the absorption spectrum, the Judd-Ofelt （JO） parameters Ω2, Ω4, and Ω6 were calculated to be 4.86 × 10-20 cm2, 2.02 × 10-20 cm2, and 1.76 ×10-20 cm2, respectively. The emission cross-section at 574 nm corresponding to the 4F9/2 →6H13/2 transition was calculated to be 0.53 ×10 20 cm2. The yellow （4F9/2 →6H13/2 transition） to blue （4F9/2 →6H15/2 transition） intensity ratio ranges up to 12.9. The fluorescence lifetime of the 4F9/2 energy level was measured to be 112.1 μs. These results reveal that Dy：Lu2O3 is a promising material for use in yellow lasers.展开更多
The crystal growth,x-ray diffraction pattern,absorption spectrum,emission spectrum,and fluorescence lifetime of a Tb：Lu2O3 single crystal were studied.Excited at 483 nm,the peak absorption cross-section was calculate...The crystal growth,x-ray diffraction pattern,absorption spectrum,emission spectrum,and fluorescence lifetime of a Tb：Lu2O3 single crystal were studied.Excited at 483 nm,the peak absorption cross-section was calculated to be 3.5×10（-22）cm2,and the full width at half maximum was found to be 2.85 nm.The Judd-Ofelt（J-O）intensity parameters 2,4,and 6 were computed to be 3.79×10（-20）cm2,1.30×10（-20）cm2,and 1.08×10（-20）cm2,with a spectroscopic quality factor 4/6 being 1.20.The emission cross-sections of green emission around 543 nm and yellow emission around 584 nm were calculated to be 9.43×10（-22）cm2 and 1.32×10（-22）cm2,respectively.The fluorescence lifetimeτexp of -5D4 was fitted to be 1.13 ms.The data suggest that the Tb：Lu2O3 crystal could be a potential candidate for green and yellow laser operation.展开更多
We show that it is possible to use a single sideband to induce two-photon transparency in a three-level cascade medium. The medium simultaneously absorbs two photons as a one-step process when the middle level is far ...We show that it is possible to use a single sideband to induce two-photon transparency in a three-level cascade medium. The medium simultaneously absorbs two photons as a one-step process when the middle level is far off one-photon resonance. A resonant sideband coupling on the upper transition and the two-photon one-step process drive the medium into a trapped state, and the dominant component is the ground state. Thus almost all population is trapped in the ground state and the two-photon absorption is dramatically suppressed. We present a numerical calculation for arbitrary values of the atomic and field parameters and also provide an analytic description for the required conditions.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11272338)the Science and Technology on Scramjet Key Laboratory Funding,China(Grant No.STSKFKT 2013004)the China Scholarship Council
文摘An accurate and reasonable technique combining direct absorption spectroscopy and laser-induced fluorescence（LIF）methods is developed to quantitatively measure the concentrations of hydroxyl in CH;/air flat laminar flame. In our approach, particular attention is paid to the linear laser-induced fluorescence and absorption processes, and experimental details as well. Through measuring the temperature, LIF signal distribution and integrated absorption, spatially absolute OH concentrations profiles are successfully resolved. These experimental results are then compared with the numerical simulation. It is proved that the good quality of the results implies that this method is suitable for calibrating the OH-PLIF measurement in a practical combustor.
文摘A combined detection system involving simultaneous LIF and contacfless-conductometric measurements at the same place of the microfluidic chip was described. The LIF measurement was designed according to the confocal principle and a moveable contactless-conduetivity detector was used in C^4D. Both measurements were mutually independent and advantageous in analyses of mixtures. Various experimental parameters affecting the response were examined and optimized. The performances were demonstrated by simultaneous detection of Rhodamine B. And the results showed that the combined detection system could be used sensitively and reliably.
基金supports from the National Natural Science Foundation of China(No.21773221 and No.21827804)the National Key R&D Program of China(No.2017YFA0303502)the Fundamental Research Funds for the Central Universities of China(No.WK2340000078)。
文摘Magnesium monofluoride(MgF)is proposed as an ideal candidate radical for direct laser cooling.Here,the rotationally resolved laser spectra of MgF for the A^(2)Π-X^(2)∑^(+) electronic transition system were recorded by using laser induced fluorescence technique.The MgF radicals were produced by discharging SF_(6)/Ar gas mixtures between the tips of two magnesium needles in a supersonic jet expansion.We recorded a total of 19 vibrational bands belonging to three sequences of Δv=0,±1 in the region of 348-370 nm.Accurate spectroscopic constants for both X^(2)∑^(+) and A^(2)Π states are determined from rotational analysis of the experimental spectra.Spectroscopic parameters,including the Franck-Condon factors(FCFs),are determined from the experimental results and the Rydberg-Klein-Rees(RKR)calculations.Significant discrepancies between the experimentally measured and RKR-calculated FCFs are found,indicating that the FCFs are nearly independent of the spin-orbit coupling in the A^(2)Π state.Potential energy curves(PECs)and FCFs determined here provide necessary data for the theoretical simulation of the laser-cooling scheme of MgF.
文摘N-Conjugated antigen was synthesized and polyclonal antibody with high specificity was obtained from immunizing animals. With this polyclonal antibody, a rapid and efficient CEIA-LIF method was developed to determine the free morphine in urine of abusers. The detection limit was calculated to be 40 ng/mL. Simulated urine samples were analyzed with good recoveries, which showed the feasibility of its application in specific morphine determination in urine of morphine abusers.
基金Project supported by the Fund of Key Laboratory of Optoelectronic Materials Chemistry and Physics,Chinese Academy of Sciences(Grant No.2008DP173016)the National Key Research and Development Program of China(Grant No.2016YFB1102202)the National Key Research and Development Program of China(Grant No.2016YFB0701002)
文摘Dy：Lu2O3 was grown by the float-zone （Fz） method. According to the absorption spectrum, the Judd-Ofelt （JO） parameters Ω2, Ω4, and Ω6 were calculated to be 4.86 × 10-20 cm2, 2.02 × 10-20 cm2, and 1.76 ×10-20 cm2, respectively. The emission cross-section at 574 nm corresponding to the 4F9/2 →6H13/2 transition was calculated to be 0.53 ×10 20 cm2. The yellow （4F9/2 →6H13/2 transition） to blue （4F9/2 →6H15/2 transition） intensity ratio ranges up to 12.9. The fluorescence lifetime of the 4F9/2 energy level was measured to be 112.1 μs. These results reveal that Dy：Lu2O3 is a promising material for use in yellow lasers.
基金Project supported by the National Natural Science Foundation of China(Grant No.61621001)the National Key Research and Development Program of China(Grant Nos.2016YFB1102202 and 2016YFB0701002)+1 种基金the Fundamental Research Funds for the Central Universities,Chinathe help of MOE Key Laboratory of Advanced Micro-Structured Materials and School of Physical Science and Technology,Guangxi University
文摘The crystal growth,x-ray diffraction pattern,absorption spectrum,emission spectrum,and fluorescence lifetime of a Tb：Lu2O3 single crystal were studied.Excited at 483 nm,the peak absorption cross-section was calculated to be 3.5×10（-22）cm2,and the full width at half maximum was found to be 2.85 nm.The Judd-Ofelt（J-O）intensity parameters 2,4,and 6 were computed to be 3.79×10（-20）cm2,1.30×10（-20）cm2,and 1.08×10（-20）cm2,with a spectroscopic quality factor 4/6 being 1.20.The emission cross-sections of green emission around 543 nm and yellow emission around 584 nm were calculated to be 9.43×10（-22）cm2 and 1.32×10（-22）cm2,respectively.The fluorescence lifetimeτexp of -5D4 was fitted to be 1.13 ms.The data suggest that the Tb：Lu2O3 crystal could be a potential candidate for green and yellow laser operation.
基金Supported by National Natural Science Foundation of China under Grant Nos 60378008 and 10574052.
文摘We show that it is possible to use a single sideband to induce two-photon transparency in a three-level cascade medium. The medium simultaneously absorbs two photons as a one-step process when the middle level is far off one-photon resonance. A resonant sideband coupling on the upper transition and the two-photon one-step process drive the medium into a trapped state, and the dominant component is the ground state. Thus almost all population is trapped in the ground state and the two-photon absorption is dramatically suppressed. We present a numerical calculation for arbitrary values of the atomic and field parameters and also provide an analytic description for the required conditions.
