为了动态控制用于植物生长的人工光源，该文提出一种以光子数作为评价标准，使红蓝光比例连续可调的LED植物生长光源的配光方法。综合考虑红、蓝2种波段光源及其他光谱的作用，该文采用白光LED与红光LED 组合配比，以正向电流下 LED 的...为了动态控制用于植物生长的人工光源，该文提出一种以光子数作为评价标准，使红蓝光比例连续可调的LED植物生长光源的配光方法。综合考虑红、蓝2种波段光源及其他光谱的作用，该文采用白光LED与红光LED 组合配比，以正向电流下 LED 的光谱密度数据作为计算基础，提出配光设计算法，实现红蓝成分有效光子数维持一定的要求下，红光与蓝光光子数比在指定区间（4：1～9：1之间）连续可调，从而满足植物不同生长状态对光质成分的需要。展开更多
Diamond reinforced copper （Cu/diamond） composites were prepared by a pressure infilla＇ation technique. The composites show a super high conductivity of 713 W.m-1.K-1 in combination with an extremely low coefficient...Diamond reinforced copper （Cu/diamond） composites were prepared by a pressure infilla＇ation technique. The composites show a super high conductivity of 713 W.m-1.K-1 in combination with an extremely low coefficient of thermal expansion （CTE） of 7.72 × 10-6 K-1 （25-100℃）, which are achieved by modifying the copper matrix with adding 0.3 wt.% of boron to get a good thermal contact between the matrix and the diamond particles. By adopting a series of postmachining techniques the composites were made into near-net-shape parts, and an electroless silver coating was also successfully plated on the composites. Finally, their potential applications in the thermal management of fight emitting diodes （LED） were illustrated via prototype examples.展开更多
Phosphor SrGa2 S4 ：Eu^2＋ was synthesized with a high temperature solid state reaction. Its absorption spectrum, photolumineseence spectra, and fluorescence lifetime were studied in details. The excitation spectrum e...Phosphor SrGa2 S4 ：Eu^2＋ was synthesized with a high temperature solid state reaction. Its absorption spectrum, photolumineseence spectra, and fluorescence lifetime were studied in details. The excitation spectrum extended from UV to visible light region, and matched the emission of GaN chip. （Sr1- xEUx）Ga2S4 emits strong green light and the concentration quenching did not occur; while the thermal quenching was evident. The emission peak shifted to long wavelength with inereasing Eu^2＋ concentration because of the changing of the crystal field strength. The lifetime of Eu^2＋ ion was in the order of microsecond, which was reasonable for d→f transition. The electroluminescence spectrum of as-fabricated PC-LED at IF=20 mA was measured and most of the blue light of blue-LED chip at 460 nm was absorbed by the phosphor and simultaneously down-converted into an intensive green light at 540 nm. The color coordinate was （0.32, 0.63）. SrGa2S4：Eu^2＋ was a promising phosphor for GaN-based green LEDs.展开更多
文摘为了动态控制用于植物生长的人工光源，该文提出一种以光子数作为评价标准，使红蓝光比例连续可调的LED植物生长光源的配光方法。综合考虑红、蓝2种波段光源及其他光谱的作用，该文采用白光LED与红光LED 组合配比，以正向电流下 LED 的光谱密度数据作为计算基础，提出配光设计算法，实现红蓝成分有效光子数维持一定的要求下，红光与蓝光光子数比在指定区间（4：1～9：1之间）连续可调，从而满足植物不同生长状态对光质成分的需要。
基金supported by the National Natural Science Foundation of China (No. 50971020)the National High-Tech Research and Development Program of China (No. 2008AA03Z505)
文摘Diamond reinforced copper （Cu/diamond） composites were prepared by a pressure infilla＇ation technique. The composites show a super high conductivity of 713 W.m-1.K-1 in combination with an extremely low coefficient of thermal expansion （CTE） of 7.72 × 10-6 K-1 （25-100℃）, which are achieved by modifying the copper matrix with adding 0.3 wt.% of boron to get a good thermal contact between the matrix and the diamond particles. By adopting a series of postmachining techniques the composites were made into near-net-shape parts, and an electroless silver coating was also successfully plated on the composites. Finally, their potential applications in the thermal management of fight emitting diodes （LED） were illustrated via prototype examples.
基金Project supported by the National Natural Science Foundation of China (20171046)
文摘Phosphor SrGa2 S4 ：Eu^2＋ was synthesized with a high temperature solid state reaction. Its absorption spectrum, photolumineseence spectra, and fluorescence lifetime were studied in details. The excitation spectrum extended from UV to visible light region, and matched the emission of GaN chip. （Sr1- xEUx）Ga2S4 emits strong green light and the concentration quenching did not occur; while the thermal quenching was evident. The emission peak shifted to long wavelength with inereasing Eu^2＋ concentration because of the changing of the crystal field strength. The lifetime of Eu^2＋ ion was in the order of microsecond, which was reasonable for d→f transition. The electroluminescence spectrum of as-fabricated PC-LED at IF=20 mA was measured and most of the blue light of blue-LED chip at 460 nm was absorbed by the phosphor and simultaneously down-converted into an intensive green light at 540 nm. The color coordinate was （0.32, 0.63）. SrGa2S4：Eu^2＋ was a promising phosphor for GaN-based green LEDs.
