Steady-state absorption and fluorescence spectra, and time-resolved fluorescence spectra of coumarin 343 （C343） were measured in different solvents. The effect of the solvent on the spectral properties and dipole mo...Steady-state absorption and fluorescence spectra, and time-resolved fluorescence spectra of coumarin 343 （C343） were measured in different solvents. The effect of the solvent on the spectral properties and dipole moment of the lowest excited state of C343 were investigated. It was found that the absorption and fluorescence spectra red-shifted slightly and strongly with increasing solvent polarity, respectively, because the charge distribution of the excited state leaded to the increasing difference between the absorption and fluorescence spectra with increasing solvent polarity. The dipole moment of the lowest excited state of C343 was determined from solvatochromic measurements and the quantum chemical calculation, and the results obtained from these two methods were fully consistent. Investigations of the time-resolved fluorescence of C343 in different solvents indicated that the fluorescence lifetimes increased nearly linearly with 4.45 ns in water. This can be ascribed between C343 and hydrogen donating increasing solvent polarity from 3.09 ns in toluene to to the intermolecular hydrogen bonding interactions solvents展开更多
The properties of n-Ge epilayer deposited on Si substrate with in-situ doping technology in a cold-wall ultrahigh vacuum chemical vapor deposition（UHVCVD） system are investigated.The growth temperature of 500℃ is o...The properties of n-Ge epilayer deposited on Si substrate with in-situ doping technology in a cold-wall ultrahigh vacuum chemical vapor deposition（UHVCVD） system are investigated.The growth temperature of 500℃ is optimal for the n-Ge growth in our equipment with a phosphorus concentration of 1018cm-3.In the n-Ge epilayer,the depth profile of phosphorus concentration is box-shaped and the tensile strain of 0.12% confirmed by x-ray diffraction measurement is introduced which results in the red shift of the photoluminescence.The enhancements of photoluminescence intensity with the increase of the doping concentration are observed,which is consistent with the modeling of the spontaneous emission spectrum for direct transition of Ge.The results are of significance for guiding the growth of n-Ge epilayer with in-situ doping technology.展开更多
The molecular structural and Raman spectroscopic characteristics of fl-carotene and lycopene are investigated by density functional calculations. The effects of molecular structure and solvent environment on the Raman...The molecular structural and Raman spectroscopic characteristics of fl-carotene and lycopene are investigated by density functional calculations. The effects of molecular structure and solvent environment on the Raman spectra are analyzed by comparing the calculated and measured results. It is found that the B3LYP/6-31G（d） method can predict the reasonable result for β-carotene, but the vl Raman activities of lycopene overflow at all the used theo- retical methods because of the longer conjugation length in β-carotene impedes the delocalization of ~r-electrons The calculated results indicate that the rotation of β-rings shortens the effective conjugation length, and results in higher frequency and lower activity of the vl mode in /q-carotene than lycopene. The measured vl bands of β-carotene and lycopene shift respectively to higher and lower frequencies in solution compared with that in crystals since the crystal packing forces can lead to different conformational variations in the carotenoids molecules. The polarized continuum model theoretical analysis suggests that solvent has slight （significant） effects on the Raman frequencies （intensities） of both carotenoids.展开更多
The exact solution of time-evolution operator is obtained by applying the gauge transformation of algebra dynamics.Such an operator describes the time-evolution of the quantum state for two inductance coupled mesoscop...The exact solution of time-evolution operator is obtained by applying the gauge transformation of algebra dynamics.Such an operator describes the time-evolution of the quantum state for two inductance coupled mesoscopic LC circuits.The zero-state responses of the charge and current to the input voltage signal are calculated.The results show that the system of inductance coupled mesoscopic LC circuits is linear and time-invariant.The zero-state responses of the charge and current are consistent with those of the corresponding macroscopic circuit.展开更多
Based on the relativistic hydrodynamic model of EM wave-spin plasmas interaction,the spin effects on the relativistic strong EM modes in magnetized plasma are investigated.The dispersion relations of the EM wave propa...Based on the relativistic hydrodynamic model of EM wave-spin plasmas interaction,the spin effects on the relativistic strong EM modes in magnetized plasma are investigated.The dispersion relations of the EM wave propagating parallel and perpendicular to the external magnetic field are obtained.Results show that the strong EM wave modes are affected by the time component of four-spin as well as the increase of electron effective mass.Especially in the case of EM wave propagating parallel to the external magnetic field,the time component of fourspin amplifies the influence of spin effects on the low-frequency modes obviously.展开更多
文摘Steady-state absorption and fluorescence spectra, and time-resolved fluorescence spectra of coumarin 343 （C343） were measured in different solvents. The effect of the solvent on the spectral properties and dipole moment of the lowest excited state of C343 were investigated. It was found that the absorption and fluorescence spectra red-shifted slightly and strongly with increasing solvent polarity, respectively, because the charge distribution of the excited state leaded to the increasing difference between the absorption and fluorescence spectra with increasing solvent polarity. The dipole moment of the lowest excited state of C343 was determined from solvatochromic measurements and the quantum chemical calculation, and the results obtained from these two methods were fully consistent. Investigations of the time-resolved fluorescence of C343 in different solvents indicated that the fluorescence lifetimes increased nearly linearly with 4.45 ns in water. This can be ascribed between C343 and hydrogen donating increasing solvent polarity from 3.09 ns in toluene to to the intermolecular hydrogen bonding interactions solvents
基金Project supported by the National Basic Research Program of China(Grant No.2013CB632103)the National Key Technology Support Program of China(Grant No.2015BAF24B01)+4 种基金the Natural Science Foundation of Fujian Province of China(Grant No.2016J05147)the Key Sci-Tech Research and Development Platform of Fujian Province,China(Grant No.2014H2002)the Provincial University Foundation of Fujian Province,China(Grant No.JK2013030)the Educational Youth Key Foundation of Fujian Province,China(Grant No.JA13210)the Scientific Research Fund of Fujian University of Technology,China(Grant No.GY-Z14073)
文摘The properties of n-Ge epilayer deposited on Si substrate with in-situ doping technology in a cold-wall ultrahigh vacuum chemical vapor deposition（UHVCVD） system are investigated.The growth temperature of 500℃ is optimal for the n-Ge growth in our equipment with a phosphorus concentration of 1018cm-3.In the n-Ge epilayer,the depth profile of phosphorus concentration is box-shaped and the tensile strain of 0.12% confirmed by x-ray diffraction measurement is introduced which results in the red shift of the photoluminescence.The enhancements of photoluminescence intensity with the increase of the doping concentration are observed,which is consistent with the modeling of the spontaneous emission spectrum for direct transition of Ge.The results are of significance for guiding the growth of n-Ge epilayer with in-situ doping technology.
基金This work was supported by the National Natural Science Foundation of China （Nos. 21003033, 11004076, 10774034 and 21173063）, the China Post- doctoral Science Foundation （No. 20100481006）, the Guangxi Natural Science Foundation （No. 2012GXNSFBA053012）, and the Research Foundation of Education Bureau of Guangxi （No. 200103YB 140）.
文摘The molecular structural and Raman spectroscopic characteristics of fl-carotene and lycopene are investigated by density functional calculations. The effects of molecular structure and solvent environment on the Raman spectra are analyzed by comparing the calculated and measured results. It is found that the B3LYP/6-31G（d） method can predict the reasonable result for β-carotene, but the vl Raman activities of lycopene overflow at all the used theo- retical methods because of the longer conjugation length in β-carotene impedes the delocalization of ~r-electrons The calculated results indicate that the rotation of β-rings shortens the effective conjugation length, and results in higher frequency and lower activity of the vl mode in /q-carotene than lycopene. The measured vl bands of β-carotene and lycopene shift respectively to higher and lower frequencies in solution compared with that in crystals since the crystal packing forces can lead to different conformational variations in the carotenoids molecules. The polarized continuum model theoretical analysis suggests that solvent has slight （significant） effects on the Raman frequencies （intensities） of both carotenoids.
基金supported by the Natural Science Foundation and the Scientific Research Foundation of the Education Department of Fujian Province,China(Nos.2008J0036,A0220001 and JA09160)
文摘The exact solution of time-evolution operator is obtained by applying the gauge transformation of algebra dynamics.Such an operator describes the time-evolution of the quantum state for two inductance coupled mesoscopic LC circuits.The zero-state responses of the charge and current to the input voltage signal are calculated.The results show that the system of inductance coupled mesoscopic LC circuits is linear and time-invariant.The zero-state responses of the charge and current are consistent with those of the corresponding macroscopic circuit.
基金supported by the National Natural Science Foundation of China under Grant No.12065011the PhD Starting Fund program of TongRen University under Grant No.trxyDH2223
文摘Based on the relativistic hydrodynamic model of EM wave-spin plasmas interaction,the spin effects on the relativistic strong EM modes in magnetized plasma are investigated.The dispersion relations of the EM wave propagating parallel and perpendicular to the external magnetic field are obtained.Results show that the strong EM wave modes are affected by the time component of four-spin as well as the increase of electron effective mass.Especially in the case of EM wave propagating parallel to the external magnetic field,the time component of fourspin amplifies the influence of spin effects on the low-frequency modes obviously.
