光场电离下玻璃微毛细管的X射线谱

利用软X射线大面积透射光栅谱仪,对超短强激光脉冲辐照下玻璃微毛细管靶的软X射线发射特性进行了研究。测得了不同的激光能量下、不同长度（3mm、6mm、9mm)的微毛细管的软X射线发射谱,并观察到随着微毛细管长度的增加,X射线发射强度增强。     

彩色组合编码条纹光栅轮廓术

研究了一种新的编码光栅投影三维轮廓术。其中投影光栅利用彩色空间红、绿、蓝三基色相互独立的特性,用彩色条纹对光栅进行编码,以白色条纹为起始位,后接红、绿、蓝（R、G、B）三种颜色的条纺组成一组。改变红、绿、蓝的排列顺序可使各组有不同的编码。根据排列组合原理,红、绿、蓝三色可有6种不同的排列方式。经过编码处理的光栅在保证测量精度不变的前提下,加大了高度测量的范围。由于每条纹只采用0和255两个状态,因此具有较强的抗干扰能力。测量的精度主要取决于图像的分辨率。     

Modelling of guided-wave Bragg gratings and grating sensors using the collocation method

We have used the collocation method to model the characteristics of guided-wave Bragg gratings. The collocation method being a total field method, takes into account all modes, guided as well as radiation. We have first studied the effect of the grating structural parameters such as the grating profile and the duty cycle of periodic variation and have shown that these can have significant effect on the Bragg wavelength and the reflection spectrum. We have then obtained the response characteristics of gratings for their use in strain, temperature and pressure sensing. Our results compare very well with available experimental results. Comparisons with the coupled mode theory have also been included.     

Automatic phase-locked control of grating tiling

The development of phased-array grating compressor is a crucial issue for the high-energy, ultra-short pulse petawatt-class lasers. Several systems have adopted the tiling-grating approach to meet the size requirements for the compression gratings. Grating tiling need to be precisely phased to ensure a transform-limited focal spot when focusing the high-energy laser pulses onto the target. Monochromatic grating automatic phasing and performance maintaining are experimentally achieved with a far-field CCD camera technique based on a two-tiling system.     

EFPI-FBG hybrid sensor for simultaneous measurement of high temperature and large strain

We report an extrinsic Fabry–Perot interferometer-fiber Bragg grating(EFPI-FBG) hybrid sensor in this letter. The interferometric cavity of the proposed hybrid sensor is composed of a glass capillary tube, a section of single-mode fiber, and a section of single-mode metal fiber with one FBG. The FBG processed by high-temperature annealing is used to measure temperature, whereas the fiber EFPI is adopted for strain measurement. One of the two aligned fibers is free along the axial direction, which is different from the traditional structure that both the fibers are fixed to glass capillary tube. Experimental results show that the sensor can measure high temperature and large strain simultaneously. The measuring range of temperature and strain for the hybrid sensor is up to 500 °C and 10,000 με, respectively. Effective temperature compensation of the hybrid sensor is realized, too.     

The distributed dynamic combined-stresses measurement of ship thruster inner-skin using fiber Bragg grating sensor rosette array

The use of a fiber Bragg grating (FBG) sensor array for the measurement of dynamic combined stress of ship thruster inner-skin is presented. The triaxial stress is detected using improved three-element rectangular rosette consisting of FBG sensors. Phase lag effect among triaxial stress sensor is considered and eliminated by employing multi-channel demodulation and improving the layout of sensor rosette array and connection layout. The tests are carried on to measure the distributed combined-stress change of ship thruster duct when ship thruster work at different rotate speed and pitch of angle. The test result are analyzed which show that measured stress are acceptable and in accord with predicted result.     

声光效应实验中叠加光栅产生的双衍射现象探究

声光效应实验光路中叠加光栅,产生双衍射现象,用光强分布测定仪测出产生的衍射图样中光强值,并用Origin7.5统计软件画出衍射3D图样,形象直观展示了两种情况下衍射光强的分布情况及变化情况。反应了基础实验在改变原实验条件下,能演示新实验现象,拓宽了基础实验原来的功能,更大程度地发挥了实验器材的最大作用。     

光纤Bragg光栅应变桩在公路边坡中的监测研究

为实现对公路边坡的稳定性安全监测,需要检测边坡的应变变化。元绿公路K77+120~K77+215段为一坡度30°、高度差达65m的边坡,由于土质松散而形成一滑坡地带,在其自然坡面前端挖掘5个30m深钻孔,把光纤Bragg光栅应变传感器分别埋入5个钻孔之中,浇灌水泥使之固定,形成5个应变桩,实现对桩体的应变监测,从而反应边坡的应变变化情况。经过两个月的监测,1孔洞到5孔洞最大应变变化依次为400με、80με、130με、-60με、46με,且依次出现在6m、16m、14m、16m、30m深度的位置。表明此边坡在6m深度及15m深度地层结构比较松散。     

Application of dynamic speckle method using in sedimentation process of silver chloride

The generation process of silver chloride was studied using dynamic speckle methods including speckle size measurement and speckle contrast measurement. The quantity and size changes of the sedimentation particles in the illuminating region were investigated and analyzed.     

应用微相关技术研究裂端弹塑性变形

测量裂端附近区域的弹塑性变形，对于研究材料的损伤或微裂纹的产生，获得材料早期的损伤信息，为预防宏观裂纹的产生及扩展具有十分重要的意义。本文用A3钢材料制作边缘带裂纹的显微拉伸试件，试件表面进行了金相处理。试件是用由计算机控制的显微拉伸台进行加载试验。在加载过程中，利用环境扫描电镜对裂端附近的显微结构进行原位观察以及扫描记录。应用数字散斑相关技术对扫描电子显微镜记录的显微结构图进行分析处理，求出裂端附近的弹塑性变形。借助扫描电子显微镜，不仅可以定性观察应力集中区微裂纹的萌生及扩展过程，还可以结合数字散斑相关技术，对微区内的弹塑性变形进行测试，是研究微区域内材料变形的一个有效手段。