基于脉冲复制的单脉冲激光对比度测量

为测量超短单脉冲激光的时间波形以及对比度信息,基于三阶强度相关原理,结合光脉冲复制技术,提出了基于脉冲复制的测量方法。对测量原理进行了详尽的理论分析。利用分步傅里叶和龙格库塔数值计算方法对测量方案做了模拟验证。基于脉冲复制的测量法能同时进行多窗口测量。通过拼接测量时间窗口,可以有效解决测量分辨率与测量时间窗口不能兼顾的问题,同时实现大时间窗口和高分辨率测量。通过将主脉冲与预脉冲分离到不同的测量窗口,避免了梯度衰减片的使用,且具有高对比度测量能力。     

Generation of new longitudinal modes in an amplifying dye solution

A novel phenomenon is reported for the first time that the generation of the newlongitudinal modes in amplifying multi-longitudinal mode laser in a dye amplifier.The newmodes are located on the violet side within the gain band of the amplifing medium.The phe-nomenon is explained by the theory of third-order nonlinear polarization in the case of four-wave resonances.The intensity of the new modes created are comparable with or even higherthan that of the original modes.The effect can be expected to serve as a new method for ex-tention of spectral tuning ranges of laser.     

一组Dawson型多金属氧酸盐和相应的有机-无机杂多化合物的超快非线性光学响应(英文)

通过时间分辨率为115fs的超快光克尔方法测量了多金属氧酸盐K₈[P₂Mo₄W₁₃M（H₂O）O₆₁]（M=Mn,Co,Ni,Cu,Zn）和相应的有机-无机杂多化合物(C₁₉H₂₅N₂)₇K₃[P₂Mo₄W₁₃MO₆₂]在830 nm处的三阶非线性光学性质.多金属氧酸盐阴离子和相应的杂多化合物都表现出很大的三阶非线性,其中M=Cu的取代物的非线性系数要比其他小一个数量级.通过比较有机-无机杂多化合物和生成前者的反应物的γ值,发现杂多化合物中的电荷转移效应极大的增强了三阶非线性光学性能.     

Cu2ZnSnS4纳米晶的制备及其三阶非线性光学性能的研究

以乙酰丙酮铜、醋酸锌、二氯亚锡、油胺和硫粉为前驱体,采用one-pot法合成出了单分散的Cu2ZnSnS4(CZTS)纳米晶.所得样品采用X射线粉末衍射仪(XRD),能量色散谱仪(EDS),透射电子显微镜(TEM),高分辨透射电子显微镜(HRTEM),光电子能谱仪(XPS),紫外-可见光谱仪(UV-vis)和Z-扫描(Z-scan)技术对其结构组成、形貌、性能等进行了表征.结果表明:所获得的产物为四方相结构的六边形CZTS纳米颗粒,直径约为10 nm.计算出尺寸大小为10 nm,13 nm的纳米晶的三阶非线性光学折射率γ(-1.08×10-15,-9.08×10-17 m2·W-1),三阶非线性光学吸收系数β(6.5×10-9,3.69×10-11 m·W-1)以及三阶非线性光学极化率χ(3)(1.49×10-9,4.35×10-10 esu).并探讨了CZTS纳米晶可能的形成机理,及引起三阶光学非线性发生变化的原因。     

On the determination of approximate periodic solutions of some non-linear ODE

We propose a numerical-symbolic method for the approximation of periodic solutions of a type of non-linear ODE. The efficiency of our method is contrasted with the harmonic balance method and with another one which combines the differential transformation method with Padé approximants on a non trivial example: the relativistic oscillator. It is shown that our method is computationally more reliable.     

带导数项的半正Right Focal边值问题单调正解的存在性

研究下列半正Right F0cal边值问题单调正解的存在性其中λ>0是一个参数,n≥3,1相似文献   

EXISTENCE OF SOLUTIONS TO A THIRD-ORDER THREE-POINT BOUNDARY VALUE PROBLEM

In this paper,we study the existence of solutions to a third-order three-point boundary value problem.By imposing certain restrictions on the nonlinear term,we prove the existence of at least one solution to the boundary value problem by the method of lower and upper solutions.We are interested in the construction of lower and upper solutions.     

常微分方程在数学建模中的应用

通过若干实例,运用高等数学中的微分方程方法建立数学模型,提高学生学习高等数学的兴趣并逐步了解数学建模的方法和思想;提高课堂讲课效果、实践素质教育改革.     

Solving (2+1)-dimensional sine-Poisson equation by a modified variable separated ordinary differential equation method

By introducing a more general auxiliary ordinary differential equation (ODE), a modified variable separated ordinary differential equation method is presented for solving the (2+1)-dimensional sine-Poisson equation. As a result, many explicit and exact solutions of the (2+1)-dimensional sine-Poisson equation are derived in a simple manner by this technique.     

固体声弹性理论、实验技术及应用研究进展

固体的声弹性对于固体的应力状态超声无损测量具有极其重要的作用.康奈尔大学的鲍亦兴教授曾经总结了1984年以前的固体声弹性理论、实验技术及工程应用方面的研究成果.系统总结了最近20多年来固体声弹性的基本理论、实验技术及其在材料科学、岩土工程等领域应力状态超声无损检测应用方面的研究进展.