大面源红外定标器热适配结构优化设计与验证

针对红外定标器在定标试验过程中因异质材料线膨胀系数不匹配导致结构热失配,造成低温状态下螺栓松动、降温速率慢、温度均匀性差,高温状态下玻璃钢隔热垫压溃等问题,开展大面源、宽温区、多材料体系红外定标器热适配结构优化设计与验证。从法向预紧力调控和面内翘曲变形控制两方面,筛选关键材料,调整装配参数,优化结构参数。采用仿真与试验相结合的手段,探究高低温状态下异质多层结构螺栓预紧力变化规律,验证红外定标器结构安全性和稳定性。最后通过升降温试验验证红外定标器关键技术指标。研究结果表明,选用聚四氟乙烯作为隔热材料,配合不锈钢螺栓,施加初始拧紧力矩介于10～18 N·m之间,调整安装孔孔径为25 mm以上,可有效控制预紧力变化,减小面内翘曲变形。全系统仿真结果表明在高低温状态下,连接安全有效的螺栓比例均达到了90%以上。热适配结构设计与优化可显著提高红外定标器降温速率,改善辐射面低温状态温度均匀性,结构安全性与稳定性满足设计要求。热适配结构优化设计方法可作为同类产品的参考。     

基于纳米Au胶表面增强拉曼光谱对水中链霉素残留量的快速检测

为实现快速检测水中硫酸链霉素(STR)的残留,探 索建立一种STR水溶液的表面增强拉曼光谱(SERS,surface enhanced Raman spectroscopy)检测方法。应用电磁炉加热以柠檬酸三钠还原氯金酸(HAucl ₄)制成的Au胶纳米颗 粒作为表面增强基底,先后分析了Au胶纳米颗粒的吸收光谱、STR水溶液的SERS以及拉曼峰 归属; 然后确定了最佳的光谱仪功率、Au胶纳米颗粒的加入量和吸附时间;最后以1031cm－1处拉曼峰作为特征峰 建立STR水溶液的标定曲线,并对标定曲线的准确度和精确度进行验证。实验结果表 明,当水中STR质量浓度范围为2.0~20.0 mg/L时,1031 cm－1处的拉曼峰强度与STR水溶液的质量浓度有良好的线性关系, 线性方程为Y=293.31X+435.42, 决定系数R²为0.933 。真实值与预测值之间的R²为0.964,均方 根误 差(RMSEP)为1.3043mg/L,回收率为92.1~133.0%,相 对标准偏差(RSD,n=5)为0.88~2.41%。     

All-optical clock recovery of NRZ data at 40 Gbit/s using Fabry-Perot filter and two-section gain-coupled DFB laser

All-optical clock recovery from 40 Gbit/s non-return-to-zero (NRZ) data has been experimentally demonstrated by using a fibre-pigtailed Fabry-Perot filter and a self-pulsing two-section gain-coupled distributed feedback laser. The recovered clock has a measured root-mean-square (RMS) timing jitter of 1.2 ps. Error-free performance has been achieved in back-to-back bit error ratio (BER) tests using the optically recovered clock.     

Securing and Self recovery of Virtual Machines in cloud with an Autonomic Approach using Snapshots

Mobile Networks and Applications - The advent of cloud computing has been so enormous that, cloud has been seen as the most enduring technology of today’s technology scenario. It is known to...     

Demonstration of an optical-label switching router with multicast and contention resolution at mixed data rates

This letter experimentally demonstrates a scalable optical-label switching router architecture that supports a limited multicast function. A semiconductor-optical-amplifier-based Mach-Zehnder interferometer wavelength converter performs multiwavelength conversion for multicast at 10 Gb/s by cross-phase modulation. With a 2.5-Gb/s unicast channel, the experiment also demonstrates contention resolution in the wavelength domain at mixed data rates.     

A contrast and comparison of near-sea surface airtemperature/humidity from GMS and SSM/I data with an improved algorithm

With data sets gained from Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSM/I) microwave channels, Geostationary Meteorological Satellite (GMS-5) infrared channels, and ship-measured data, the statistical algorithms to estimate sea surface temperature and near-sea surface air humidity around Taiwan and the South China Sea areas are developed. Then a new, improved method to estimate near-sea surface air temperature based on the algorithm proposed by Konda et al. (1996) is established in this study. The results estimated with SSM/I data show that the root mean square error (RMSE) of SST, near-sea surface air humidity and air temperature over the oceans around Taiwan and the South China Sea are 1.2 K,1.43 g/kg, and 1.6 K, respectively. The results with GMS data are 1.7 K,1.71 g/kg and 1.7 K, respectively. The results also show that the improvements in the algorithm of Konda et al. simplify the computation scheme, improve the accuracy, and match the regional ocean-atmosphere properties in retrieving near-sea surface air temperature. The estimate produced using SSM/I and GMS data also show good consistency between them, both in temporal and spatial variations. Basically, the accuracy of this result implies strong potential for application of satellite data to relative studies and operational work in the ocean-atmosphere interaction