Application of millimeter-sized polymer cylindrical lens array concentrators in solar cells

A unique method is proposed to encapsulate solar cells and improve their power conversion efficiency by using a millimeter-sized cylindrical lens array concentrator. Millimeter-sized epoxy resin polymer(ERP) cylindrical lens array concentrators are fabricated by the soft imprint technique based on polydimethylsiloxane stamps. The photovoltaic measurements show that millimeter-sized ERP cylindrical lens array concentrators can considerably improve the power conversion efficiency of silicon solar cells. The validity of the proposed method is proved by the coupled optical and electrical simulations. The designed solar cell devices with the advantages of high-efficiency and convenient cleaning are very useful in practical applications.     

锌含量对Zn/HZSM-5催化剂性能的影响

 研究了不同锌含量的Zn／HZSM－5分子筛的表面酸性及其对正己\r\n烷芳构化反应的催化活性、选择性和稳定性．结果表明,锌组元的引入\r\n减少了HZSM－5表面的B酸,增加了L酸,总酸量增大;正己烷转化率随\r\n锌含量的增加先降低后升高;芳烃产率和芳构化选择性则随锌含量的增\r\n加先增大后趋于平缓;反应过程中催化剂的积炭速度、孔体积和比表面\r\n积下降速度都随着锌含量的增加而加快;锌含量大于1％时,Zn／HZSM\r\n－5的催化稳定性不如HZSM－5,且随着锌含量的增加失活速度加快．优\r\n选的锌含量为1．0％～2．9％．此外,讨论了Zn／HZSM－5的催化性能\r\n与其表面性质的关系．     

李color代数的T~*-扩张

介绍了李color代数的T*-扩张的定义,并证明李color代数的很多性质,如幂零性、可解性和可分解性,都可以提升到它的T*-扩张上.还证明在特征不等于2的代数闭域上,有限维幂零二次李color代数A等距同构于一个幂零李color代数B的T*-扩张,并且B的幂零长度不超过A的一半.此外,用上同调的方法研究了李color代数的T*-扩张的等价类.     

Measurement of the third order nonlinear optical coefficients of GaP and chirp parameter of laser pulse

The spectral resolved femtosecond pump-probe experiment is applied to measure the third order nonlinear refractive index coefficient, two-photon absorption coefficient of GaP crystal, and the chirp parameter of the input laser pulses. The results show that nonlinear refractive index coefficient is 2× 10-18 m2/W, twophoton absorption coefficient is 2× 10-11 m/W at wavelength of 783.5 nm, and the chirp parameter of laser pulse is l× 1025 s-2. Furthermore, the mechanism of nonlinear refraction due to two-photon absorption in GaP crystal and experimental results are discussed.     

Measurement of the third order nonlinear optical coefficients of GaP and chirp parameter of laser pulse

The spectral resolved femtosecond pump-probe experiment is applied to measure the third order nonlinear refractive index coefficient, two-photon absorption coefficient of GaP crystal, and the chirp parameter of the input laser pulses. The results show that nonlinear refractive index coefficient is 2 × 10 -18 m2/W, two-photon absorption coefficient is 2×10-11 m/W at wavelength of 783.5 nm, and the chirp parameter of laser pulse is 1×1025 s-2. Furthermore, the mechanism of nonlinear refraction due to two-photon absorption in GaP crystal and experimental results are discussed.     

挥发性有机物的非接触SERS检测

挥发性有机物在自然环境中普遍存在,对人体健康造成显著影响,为此亟待发展高灵敏度的快速识别和检测技术。本文通过制备和优化表面增强拉曼散射(surface-enhanced Raman scattering,SERS)基底,实现了强吸附和弱吸附型挥发性有机物的检测。首先利用化学方法合成了粒径约为30nm的均匀准球形金纳米粒子,该粒子具有SERS效应以及良好的化学稳定性,以该纳米粒子为单元,通过气液两相界面自组装技术制备增强性能好、SERS信号均匀的金纳米粒子单层膜(Au MLF),并以此为SERS基底对挥发性有机物苯硫酚进行了检测。为了实现弱吸附挥发物质的检测,对Au MLF表面进行了修饰,构建了聚二甲基硅氧烷(PDMS)-Au MLF复合基底,实现了苯及二甲苯等弱吸附型挥发性有机物的检测。     

较高阶非线性抽运-探测过程中的空间效应

在飞秒抽运一探测光谱技术中,空间分辨的探测光信号反映了在不同空间位置的材料的非线性效应。当抽运光强度增大时,探测光信号中会出现明显的高阶特别是五阶非线性效应。利用劈裂算子方法直接解决了一维非线性传播方程的问题。在数值模拟中,研究了在不同抽运强度和位置下的抽运一探测过程中的五阶非线性效应。在足够高的抽运场下,探测信号出现清晰的振荡,显示了三阶和五阶非线性效应之间的干涉。当空间位置离抽运场中心足够远时,五阶比三阶非线性效应的衰减快得多,对其物理机制和趋势进行了定性的讨论。