Near IR reflective functional material was made via hollow ballotini enwrapped by TiO2 according to IR reflective principles. Metatitanic acid covers on the surface of hollow ballotini through electrostatic attraction...Near IR reflective functional material was made via hollow ballotini enwrapped by TiO2 according to IR reflective principles. Metatitanic acid covers on the surface of hollow ballotini through electrostatic attraction as pH is less than 2.5. The results of SEM and XRD spectrum show that TiO2 enwraps hollow ballotini well and the crystal form is anatase. When TiO2 covering thickness is below 0.5 μm, reflectance swells along with the increase of thickness, whereas above 0.5 μm it keeps stable. Coatings made from mixing enwrapped I-IB with styrene-acrylic latex were coated on aluminum foil, and reflectances were mensurated. It is found that reflectance keeps stable when the coating can wrap the base and reflectances of the coating in visible range and in near IR range are 86% and 81%, resoectively.展开更多
A multiple-scattering chtster method is employed to calculate the oxygen K-edge near-edge X-ray absorption fine structure of N20/Ir（110） and its monolayer. Two peaks and one weak resonance appear in both cases. The ...A multiple-scattering chtster method is employed to calculate the oxygen K-edge near-edge X-ray absorption fine structure of N20/Ir（110） and its monolayer. Two peaks and one weak resonance appear in both cases. The self- consistent field DV-Xa calculations of the peaks and resonance show that the physical origin of the pre-edge peak x is different from those of the main peak 1 and the other weak resonance al. This setup is intrinsic to the N20 monolayer, owing to the interaction between the neighbouring molecular chains in the monolayer and partly to the adsorbed atomic oxygen, according to both the theoretical and experimental data.展开更多
Near-IR femtosecond lasers have been proposed to produce high-field terahertz radiation in the air via the laser-plasma interaction, but the physical mechanism still needs to be further explored. In this work, we theo...Near-IR femtosecond lasers have been proposed to produce high-field terahertz radiation in the air via the laser-plasma interaction, but the physical mechanism still needs to be further explored. In this work, we theoretically investigate the effect of the two-color laser wavelength on the terahertz generation in the air based on a transient photocurrent model.We show that the long wavelength laser excitation can greatly enhance the terahertz amplitude for a given total laser intensity. Furthermore, we utilize a local current model to illustrate the enhancement mechanism. Our analysis shows that the terahertz amplitude is determined by the superposition of contributions from individual ionization events, and for the long wavelength laser excitation, the electron production concentrates in a few ionization events and acquires the larger drift velocities, which results in the stronger terahertz radiation generation. These results will be very helpful for understanding the terahertz generation process and optimizing the terahertz output.展开更多
2MASS(Two Micron All Sky Survey)以相当高的内部一致性和精确度在近红外波段对整个天空进行了巡天观测,并通过数据处理把原始数据转变为对天文学有用的图像、星等和位置的列表。较详细介绍了2MASS的科学意义、巡天成果、数据特征以及...2MASS(Two Micron All Sky Survey)以相当高的内部一致性和精确度在近红外波段对整个天空进行了巡天观测,并通过数据处理把原始数据转变为对天文学有用的图像、星等和位置的列表。较详细介绍了2MASS的科学意义、巡天成果、数据特征以及利用2MASS观测数据所开展的部分工作。展开更多
文摘Near IR reflective functional material was made via hollow ballotini enwrapped by TiO2 according to IR reflective principles. Metatitanic acid covers on the surface of hollow ballotini through electrostatic attraction as pH is less than 2.5. The results of SEM and XRD spectrum show that TiO2 enwraps hollow ballotini well and the crystal form is anatase. When TiO2 covering thickness is below 0.5 μm, reflectance swells along with the increase of thickness, whereas above 0.5 μm it keeps stable. Coatings made from mixing enwrapped I-IB with styrene-acrylic latex were coated on aluminum foil, and reflectances were mensurated. It is found that reflectance keeps stable when the coating can wrap the base and reflectances of the coating in visible range and in near IR range are 86% and 81%, resoectively.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10904134 and 10802083)
文摘A multiple-scattering chtster method is employed to calculate the oxygen K-edge near-edge X-ray absorption fine structure of N20/Ir（110） and its monolayer. Two peaks and one weak resonance appear in both cases. The self- consistent field DV-Xa calculations of the peaks and resonance show that the physical origin of the pre-edge peak x is different from those of the main peak 1 and the other weak resonance al. This setup is intrinsic to the N20 monolayer, owing to the interaction between the neighbouring molecular chains in the monolayer and partly to the adsorbed atomic oxygen, according to both the theoretical and experimental data.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51132004,11604205,and 11474096)Science and Technology Commission of Shanghai Municipality,China(Grant No.14JC1401500)+1 种基金Shanghai Municipal Education Commission,China(Grant No.ZZGCD15066)Foundation of Fujian Educational Committee,China(Grant No.JAT160412)
文摘Near-IR femtosecond lasers have been proposed to produce high-field terahertz radiation in the air via the laser-plasma interaction, but the physical mechanism still needs to be further explored. In this work, we theoretically investigate the effect of the two-color laser wavelength on the terahertz generation in the air based on a transient photocurrent model.We show that the long wavelength laser excitation can greatly enhance the terahertz amplitude for a given total laser intensity. Furthermore, we utilize a local current model to illustrate the enhancement mechanism. Our analysis shows that the terahertz amplitude is determined by the superposition of contributions from individual ionization events, and for the long wavelength laser excitation, the electron production concentrates in a few ionization events and acquires the larger drift velocities, which results in the stronger terahertz radiation generation. These results will be very helpful for understanding the terahertz generation process and optimizing the terahertz output.
