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A novel kind of octagonal dual-concentric-core photonic crystal fiber (PCF) is calculated with the finite element method (FEM) and proposed for broadband compensation. In order to realize highly negative dispersion, the hole diameter of the second ring is reduced relative to conventional PCFs. Numerical simulation results show that when the diameters of large holes and small holes are 0.77 pm and 0.5 #m, respectively, and the pitch of the adjacent rings is 1.1 μm, the negative dispersion can achieve about 840 ps.nm^-1.km^-1 at 1 550 nm and the dispersion slope can match with single mode fiber (SMF-28) perfectly. This PCF can compensate the positive dispersion and also its slope of about 50 times its length of SMF-28 fiber, which is suitable for C-band optical fiber telecommunication as a dispersion compensation fiber. 相似文献
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以异佛尔酮二异氰酸酯(IPDI)、聚醚二醇(N-210)、二羟甲基丙酸(DMPA)、一缩二乙二醇(DEG)、三羟甲基丙烷(TMP)及纳米氧化锡锑(ATO)浆料为主要原料,制备了稳定的纳米ATO改性水性聚氨酯(APU)乳液。 粒径测试及透射电子显微镜(TEM)观察显示,纳米ATO在水性聚氨酯中分散较好,乳液粒径均小于100 nm; FTIR分析表明,纳米ATO粒子与水性聚氨酯(WPU)间可能存在化学键; 热重分析(TGA)测试显示,随纳米ATO添加量的增加,胶膜最大热分解温度逐渐提高,最大提高了约20 ℃;紫外-可见-近红外吸收及保温性能测试表明,随着纳米ATO添加量的提高,胶膜在800~2500 nm的透过率逐渐降低,但涂层在可见光区透过率均超过70%,热阻率由1.34×10-2 m2·℃/W提高至3.17×10-2 m2·℃/W。 相似文献
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给出脉冲激光作用块状靶材的烧蚀模型.根据能量平衡原理,导出烧蚀面的位置随时间的变化关系.利用绝热近似、温度连续性条件和能量平衡原理来获得烧蚀面与固液相界面边界条件.结合热传导方程,利用精确解与积分近似法相结合的方案,给出固液两相的温度分布与时间和位置的变化关系,以及固液相界面的位置随时间的变化规律,并与已有的理论和实验结果进行比较.最后以铝靶为例计算模拟了激光烧蚀的全过程计算.
关键词:
脉冲激光
等离子体
固液相界面
烧蚀面 相似文献
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Effect of Pulse Width and Fluence of Femtosecond Laser on Electron--Phonon Relaxation Time 总被引:1,自引:0,他引:1 下载免费PDF全文
The electron phonon relaxation time as functions of pulse width and fluence of femtosecond laser is studied based on the two-temperature model. The two-temperature model is solved using a finite difference method for copper target. The temperature distribution of the electron and the lattice along with space and time for a certain laser fluence is presented. The time-dependence of lattice and electron temperature of the surface for different pulse width and different laser fluence are also performed, respectively. Moreover, the variation of heat-affected zone per pulse with laser Auence is obtained. The satisfactory agreement between our numerical results and experimental data indicates that the electron-phonon relaxation time is reasonably accurate with the influences of pulse width and Auence of femtosecond laser. 相似文献
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证得:在Banach空间中,相对紧集上的恒等算子可由一列有限秩连续拟线性投影算子一致逼近.由此得到:线性算子为紧线性算子必须且仅须它可由一列有限秩连续齐性算子一致逼近. 相似文献
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Characteristics of Plasma Shock Waves Generated in the Pulsed Laser Ablation Process 总被引:2,自引:0,他引:2 下载免费PDF全文
We modify the Sedov theory to describe plasma shock waves generated in a pulsed laser ablating process,We also study the propagation characteristics of plasma shock during the preparation process of functional thin films deposited by a pulsed laser,In particular,we discuss in detail the temporal behaviour of energy causing the difference of the propagation characteristics between the plasma shock wave and the ideal shock wave in the point explosion model.Under the same experimental conditions,the theoretical results calculated with our modified Sedov theory are in good agreement with the existing experimental data. 相似文献
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从Haun的PZT热力学理论出发,给出了PZT四方相区介电常数εr与晶格畸变c/a关 系的基本方程,并深入地根据相关实验资料和物理图像的合理推论,建立了关于晶格畸变c/ a与介电常数εr相互依赖的基本关系式.然后,根据该基本关系式仔细地研究了PZT四 方相区晶格畸变c/a对介电常数εr影响的物理图像.与相关实验资料比较表明,基本 关系式得到的介电常数εr随晶格畸变c/a的变化规律,与相关实验结果相比较,两者 吻合得
关键词:
晶格畸变
r')" href="#">介电常数εr
四方相
PZT 相似文献