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841.
A wave-coupling theory of linear electro-optic (EO) effect for ultrashort laser pulses has been developed. As one of its applications,
the linear EO effect of ultrashort Gaussian pulses propagating in LiNbO3 crystal is demonstrated, with the intensity lower than the damage threshold. It is found that the EO effect is sensitive
to both the azimuth angle and the polar angle of wave vector of light. And the larger the applied electric field, the shorter
the crystal used for optimization of EO coupling is. The numerical results show that, with the duration of input pulse changing
from 150 fs to 5 fs, the durations of output pulses are broadened due to the group-velocity dispersion, as well as the first-
and second-order refractive dispersion. In addition, when input pulse duration is larger than 20 fs, in contrast with zero
chirp, the output durations can be slightly compressed if a positive chirp input pulse is used. The validities of slowly varying
amplitude approximation and continuous wave approximation are also discussed. The influence of self-phase modulation and cross-phase
modulation on the EO effect is also discussed briefly. 相似文献
842.
Composite fibrous membranes based on poly(acrylonitrile)(PAN)-poly(vinyl chloride)(PVC) have been prepared by electrospinning. The fibrous membranes are made up of fibers of 850- to 1,300-nm diameters. These fibers are stacked in layers to produce a fully interconnected pore structure. Polymer electrolytes were prepared by immersing the fibrous membranes in 1 M LiClO4-PC solution for 60 min. The condition of pure PAN polymer electrolytes is jelly, which has poor mechanical performance and cannot be used. But when PVC with a good mechanical stiffener was added to PAN, the condition of composite PAN?CPVC polymer electrolytes becomes free-standing. In addition, the optimum electrochemical properties have been observed for the polymer electrolyte based on PAN?CPVC (8:2, w/w) to show ionic conductivity of 1.05?×?10?3 S cm?1 at 25 °C, anodic stability up to 4.9 V versus Li/Li+, and a good compatibility with lithium metal resulting in low interfacial resistance. The promising results showed that fibrous PEs based on PAN?CPVC (8:2, w/w) have good mechanical stability and electrochemical properties. This shows a great potential application in polymer lithium-ion batteries. 相似文献
843.
Peng Zhou Hongliang Ma Yingying Du Yongmei Han Bo Lu Minjian Zhong 《Applied Physics A: Materials Science & Processing》2011,102(2):295-299
Crystalline TiO2 was induced three dimensionally inside Bi-free glass sample by an 800 nm, 250-kHz femtosecond laser irradiation. Micro-Raman
spectra analysis indicated that the laser-induced crystals in the focal point of the laser beam were monophase TiO2 rutile. Continuous crystalline lines were written through moving the focal point of the laser beam inside the glass. The
results demonstrate that this technique is a convenient method to engrave three-dimensional patterns of crystals for fabricating
integrated optical devices in transparent materials. 相似文献
844.
845.
运用时域有限差分方法,研究了光栅减反层结构对太阳能电池光电转换效率及储能效果的影响.具体从光栅形状、高度以及光栅表面金属薄膜厚度出发.结果表明经光栅减反层优化表面结构的太阳能电池的光电转换效率显著增大,储能效果大大得到提升.尤其是三角形光栅太阳能电池.随着镀层厚度的增加,储能效果增加,但当薄膜厚度过厚时,储能效果反而降低. 相似文献
846.
高分辨连续光源石墨炉原子吸收光谱法测定面制食品中的铝 总被引:3,自引:0,他引:3
使用微波消解-高分辨连续光源石墨炉原子吸收光谱法测定四种面制食品(挂面、饺子皮、油条和梳打饼干)中铝的含量.样品置于密闭聚四氟乙烯消解罐中经HNO3和H2O2混合溶液完全消解.对微波消解条件、灰化温度和原子化温度进行了优化.确定最佳实验条件为:消解液HNO3和H2O2体积比7∶1,微波功率1 000 W,190℃消解4... 相似文献
847.
采用了熔盐法新工艺制备了纯相与掺钒的MnNb2O6粉晶,利用X射线衍射仪(XRD),扫描电子显微镜(SEM),能谱分析(EDX),透射电子显微镜(TEM)、高分辨透射电镜(HRTEM)和电子衍射(SAED)分析了其物相、形貌及微结构.结果表明合成产物为正交晶系钶铁矿型MnNb2O6;在不同的熔盐中合成出了棒状、片状与长方体形貌的纯相产物.讨论了温度与掺杂对结构与形貌的影响,HRTEM与SAED分析表明了产物的各向异性生
关键词:
熔盐法
结构与形貌
掺杂
反铁磁性 相似文献
848.
通过构造适当的关联函数,计算B→π跃迁形状因子fB+π(q2),fBπ(q2)和标量形状因子f0(q2),从而就能研究轻子质量对B0→π-+ν(l=e,μ,τ)衰变过程的影响.首次分别计算B0→π-e+νe,B0→π-μ+νμ,B0→π-τ+ντ衰变过程的分支比,并发现轻子质量me,mμ可以忽略,但重轻子质量mτ不能忽略,它对分支比计算有一定的贡献.把计算结果与最近的实验数据进行比较,发现理论结果与实验数据基本符合. 相似文献
849.
850.
We report on the existence of surface dark screening solitons at the interface between a dielectric medium (air) and a self-defocusing nonlinear material, taking advantage of photorefractive diffusion and drift nonlinearities. It is very interesting that a surface dark soliton is just like half of a dark soliton in bulk, but not a whole dark soliton propagating along surface. The excitation, propagation, and stability of this type of soliton are studied by using the beam-propagation method. Another interesting thing is that this type of dark soliton can be excited by a planar light beam without a necessary dark notch. 相似文献