Anti-Stokes Frequency Shift and Evolution in Polarization-Maintaining Photonic Crystal Fiber with Two-Zero Dispersion Wavelengths

Using the tunable pump pulses with about lOO fs pulse duration and 1064 nm central wavelength; the polarization-, wavelength- and power-dependent anti-Stokes lines are generated and modulated simultaneously in a polarization-maintaining photonie crystal fiber （PM-PCF） with two zero-dispersion wavelengths. By accurately controlling the polarization directions, the wavelength and the power of the pump pulse in the fiber anomalous region close to the second zero-dispersion wavelength of the PM-PCF, the output anti-Stokes pulse spectra can be tuned between 563 nm and 603 nm, which is in good agreement with the theoretical simulation. The color conversion of the mode image from yellow to orange is also observed with the different polarization pump pulses. These results can be attributed to the combined interaction between the fiber birefringence （including linear- and nonlinear- birefringence） and dispersion, and are attributed to phase-matching parametric four-wave mixing.     

微尺度驻停气泡柔性气-液界面抗流体剪切能力

在微流控系统中,稳定、可控的柔性气-液界面可实现声流体颗粒富集、微纳操作、快速气-液反应等各种实际物理和生化应用.微流道内气-液界面的抗流体剪切能力对于增强微尺度下气-液界面的可控性具有十分重要的意义.为此,文章研究了具有高稳定性、高可控性、可阵列化的微尺度驻停气泡现象.利用嵌入局部裂隙的微流道以及与之平行的气体流道,可对驻停气泡的生成和形态进行有效调节,并利用其可控的气-液界面实现多种功能化应用.在此基础上,文章进一步研究柔性可控气-液界面的抗流体剪切能力,对形态变化中的气-液界面受力进行分析,利用仿真和实验手段研究不同状态下气-液界面的形状特征,研究不同的液体驱动压力、裂隙尺寸以及裂隙形状对气-液界面抗剪切能力的影响,并将界面的曲率半径作为气泡驻留与否的判定依据.文章对驻停气泡柔性气-液界面抗流体剪切能力的研究有助于优化其控制方法,增强其控制稳定性并拓展其潜在应用场合.      

微观相场法模拟Ni75Al5.3V19.7中L12和D022结构反位缺陷的演化

运用微观相场法研究Ni75Al5.3V19.7合金沉淀过程中L12结构和D022结构反位缺陷发现:在沉淀初期,L12结构反位缺陷AlNi,Vni,NiA1,D022结构反位缺陷Vni,AlNi,Ni,AlV的浓度均从初始高度反位状态随沉淀过程的进行逐渐减小并趋于一平衡值;沉淀中后期,L12结构和D022结构长大,反位缺陷浓度始终保持平衡,平衡时L12结构的α格点反位缺陷AlNi,Vni,D022结构的α格点反位缺陷VNI,AlNI的浓度均在10-2数量级,Ll2结构和D022结构的β格点的反位缺陷NiA1,NiV,的浓度在10-1数量级,NiAl,NiV反位缺陷分别是这两种结构的主要反位缺陷类型;第三组元在有序相中有择优占位倾向,V原子优先占据L12:结构的β格点,Al原子优先占据D022结构的α格点.     

用于干涉光谱测量的分波阵面干涉仪及其光程扫描方式

本文主要研究能用于干涉光谱测量的分波阵面干涉仪的原理,建立理论模型,并采用标量电场复振幅计算干涉仪的远场干涉光强分布,其结果很接近光栅.文章讨论了波长、周期常量、周期数与衍射角的关系,并讨论了干涉图的探测.理论计算的结果由相应的实验结果加以证实.另外文章对光程扫描方式进行了比较和讨论.     

基于室温液态金属热虹吸效应的自驱动热量传递方法的数值模拟

利用芯片热量驱动的液态金属散热技术是一种高效灵巧的热管理方法,在许多应用场合具有独特价值.本文采用数值手段对基于室温液态金属热虹吸效应的自驱动热量传递方法进行了研究,探明了冷端的壁温、环路方向、环路管径的大小对此种方法流动、传热性能的影响,为该技术的实际应用提供了数据支持。     

M-矩阵Sylvester方程的一类Smith-like迭代法（英文）

本文研究了M-矩阵Sylvester方程的数值解法,这类矩阵方程广泛出现在科学计算和工程应用的许多领域.利用M-矩阵的性质和Smith方法的思想,提出了一类Smith-like迭代法以求解M-矩阵Sylvester方程,并给出了新方法的收敛性分析.数值实验表明,新方法是可行的,而且在一定条件下也是较为有效的.     

时间平移对称性与能量守恒

从对称性原理出发，证明了能量守恒定律，并对时间平移对称性与能量守恒作了简单的几何表述。     

Compression of Intense Laser Pulse through Filamentation in an Argon-Filled Cell

We demonstrate a pulse compression technique through filamentation in an argon-filled cell. By using a pair of chirped mirrors for dispersion compensation, we have successfully compressed the 53 fs pulse to 15 fs with good spatial qualities and good pulse stability. The total transmitted efficiency is more than 75%. The influence of the experiment parameters to the compressed pulses is also studied experhnentally.     

考虑冷热刀刀头温度响应对制定肿瘤治疗计划的影响

本文对冷热联合治疗肿瘤过程中在体生物组织的温度响应进行了深入的数值研究。组织被当作非理想材料,在一定的温度范围内冷冻和融化,并且考虑了未冻结组织和未损伤组织区域的血液灌注及代谢产热的影响。对比考虑和不考虑冷热刀刀头温度响应两种情形的计算结果表明,拟定治疗计划中若不考虑刀头温度响应,则有可能会造成冷热剂量的不足,从而无法彻底杀灭肿瘤。     

Interaction of Shock Waves in Cement Mortar Plate Investigated by the Digital Speckle Correlation Method

Interaction of shock waves in cement mortar plate is studied by digital speckle correlation method and digital high-speed photography technique. When the plates were destroyed by two detonators exploding at the same time, variation of shock wave field is obtained. Experimental results show that the interaction of shock waves will result in a nonlinear huge increase of local normal strain, leading to large deformation and serious destruction. However, the occurrence of this strongly nonlinear phenomenon sensitively depends on the interval between detonators, and it will only appear when the interval is smaller than the diameter of the region where shock waves exist.