In the medical field, there are growing interests in applied research such as in vivo fluorescence monitoring because of excellent body transmission characteristic of the near-infrared light. However, optical noise by...In the medical field, there are growing interests in applied research such as in vivo fluorescence monitoring because of excellent body transmission characteristic of the near-infrared light. However, optical noise by excitation light and illumination equipment for medical applications such as interior light, surgical light decrease efficiency of the fluorescent signal when observers such as surgeons confirm fluorescence signals in medical field. To solve these problems in medical field, we have analyzed external noise factors by effect on image realization, quantification of optical noise generation by external factors, and have suggested methods of minimize the optical noise in this paper. In case of fluorescence imaging in the operating room, it has been confirmed that fluorescent excitation light, interior light and surgical light are factors to generate optical noise. To acquire near-infrared fluorescence images and to compare fluorescence contrast under conditions of darkroom, interior light and surgical light, light emitting diodes (LEDs) sources that have peak wavelength at 740, 760 and 780 nm respectively were used as excitation light sources. In addition, short-pass filter which has transmission edge at 775 nm has been applied to minimize the optical noise in each external noise factor. By comparing contrast of each image before and after use of the short-pass filter, we confirmed that optical noise reduced 49%, 56% and 66% in external noise factors respectively.展开更多
In this work, the photoluminescence（PL） of NaScP2O7：Eu^2＋ and NaScP2O7：Eu^2＋,Mn^2＋ was investigated. Phase purity was checked using X-ray powder diffractometry（XRD）. PL excitation and emission spectra were re...In this work, the photoluminescence（PL） of NaScP2O7：Eu^2＋ and NaScP2O7：Eu^2＋,Mn^2＋ was investigated. Phase purity was checked using X-ray powder diffractometry（XRD）. PL excitation and emission spectra were recorded to elucidate the PL properties of NaScP2O7：Eu^2＋ and NaScP2O7：Eu^2＋,Mn^2＋. Furthermore, fluorescence lifetime measurements were performed. PL and lifetime measurements were carried out from 10 to 525 K. Moreover, the Eu^2＋ site occupation was discussed. It turned out that the incorporated Eu^2＋ ions substituted for Na＋ site and occupied two different sites. Temperature dependent PL measurements indicated the emission intensity decreased with increasing temperature due to temperature quenching in NaScP2O7：Eu^2＋. Fluorescence lifetimes of Eu^2＋ in NaScP2O7：Eu^2＋ almost did not change with a decay constant τ=~0.53 μs in the temperature range of 10–280 K, and then shortened due to temperature quenching. The luminescent lifetime reached ~0.05 μs at T=525 K. Finally, it was found that energy transfer occurred from Eu^2＋ to Mn^2＋ in co-doped NaScP2O7：Eu^2＋,Mn^2＋.展开更多
Free surface vortex control is vital in a pump sump system because the air absorbed by free surface vortex induc- es noise, vibration, and cavitation corrosion on the pumping system. In this study, the change of free ...Free surface vortex control is vital in a pump sump system because the air absorbed by free surface vortex induc- es noise, vibration, and cavitation corrosion on the pumping system. In this study, the change of free surface vor- tex and air absorption in a pump intake has been investigated by the Volume of Fraction （VOF） method with steady multiphase flow model in order to represent the behavior of the free surface vortex exactly. The homoge- neous free surface model is used to apply interactions of air and water. The results show that air intake by the free surface vortex motion can be visualized using the iso-surface of air volume fraction. The vortices make an air column from the free surface to the pump intake. Also, it was found that the flee surface vortex can be controlled by installing curtain walls.展开更多
文摘In the medical field, there are growing interests in applied research such as in vivo fluorescence monitoring because of excellent body transmission characteristic of the near-infrared light. However, optical noise by excitation light and illumination equipment for medical applications such as interior light, surgical light decrease efficiency of the fluorescent signal when observers such as surgeons confirm fluorescence signals in medical field. To solve these problems in medical field, we have analyzed external noise factors by effect on image realization, quantification of optical noise generation by external factors, and have suggested methods of minimize the optical noise in this paper. In case of fluorescence imaging in the operating room, it has been confirmed that fluorescent excitation light, interior light and surgical light are factors to generate optical noise. To acquire near-infrared fluorescence images and to compare fluorescence contrast under conditions of darkroom, interior light and surgical light, light emitting diodes (LEDs) sources that have peak wavelength at 740, 760 and 780 nm respectively were used as excitation light sources. In addition, short-pass filter which has transmission edge at 775 nm has been applied to minimize the optical noise in each external noise factor. By comparing contrast of each image before and after use of the short-pass filter, we confirmed that optical noise reduced 49%, 56% and 66% in external noise factors respectively.
基金Project supported by the Science and Technology Program of Hunan Province(2010FJ3092)
文摘In this work, the photoluminescence（PL） of NaScP2O7：Eu^2＋ and NaScP2O7：Eu^2＋,Mn^2＋ was investigated. Phase purity was checked using X-ray powder diffractometry（XRD）. PL excitation and emission spectra were recorded to elucidate the PL properties of NaScP2O7：Eu^2＋ and NaScP2O7：Eu^2＋,Mn^2＋. Furthermore, fluorescence lifetime measurements were performed. PL and lifetime measurements were carried out from 10 to 525 K. Moreover, the Eu^2＋ site occupation was discussed. It turned out that the incorporated Eu^2＋ ions substituted for Na＋ site and occupied two different sites. Temperature dependent PL measurements indicated the emission intensity decreased with increasing temperature due to temperature quenching in NaScP2O7：Eu^2＋. Fluorescence lifetimes of Eu^2＋ in NaScP2O7：Eu^2＋ almost did not change with a decay constant τ=~0.53 μs in the temperature range of 10–280 K, and then shortened due to temperature quenching. The luminescent lifetime reached ~0.05 μs at T=525 K. Finally, it was found that energy transfer occurred from Eu^2＋ to Mn^2＋ in co-doped NaScP2O7：Eu^2＋,Mn^2＋.
基金supported by"BK21 Plus project"and"Human Resources Program in Energy Technology"(KETEP)granted financial resource from the Ministry of Trade,Industry&Energy,Republic of Korea.(No.20164010200940)
文摘Free surface vortex control is vital in a pump sump system because the air absorbed by free surface vortex induc- es noise, vibration, and cavitation corrosion on the pumping system. In this study, the change of free surface vor- tex and air absorption in a pump intake has been investigated by the Volume of Fraction （VOF） method with steady multiphase flow model in order to represent the behavior of the free surface vortex exactly. The homoge- neous free surface model is used to apply interactions of air and water. The results show that air intake by the free surface vortex motion can be visualized using the iso-surface of air volume fraction. The vortices make an air column from the free surface to the pump intake. Also, it was found that the flee surface vortex can be controlled by installing curtain walls.
