Stable single longitudinal mode fiber ring laser based on polarization maintaining erbium doped fiber

A stable single longitudinal mode (SLM) fiber ring laser that incorporates polarization maintaining erbium doped fiber (PM EDF) acting as gain medium and saturable absorber is proposed and demonstrated. Both theoretical deviation and experimental result prove that optical intensity is time invariant when the laser operates in single longitudinal mode, the SLM operation can be approximately verified by optical intensity analysis, which is practical to analyze longitudinal mode in the application of engineering. The linewidth of the fiber ring laser is measured by the delayed self-heterodyne interferometery, and an acousto-optic frequency shifter is employed to shift the lasing frequency and eliminate zero frequency interfere. The SLM operation is verified by the scanning Fabry–Perot interferometer, whereas the lasing frequency drift slowly during a period of 2 h, PM EDF is proved to be effective on suppressing mode hopping and selecting longitudinal mode.     

陶瓷非物质文化遗产保护传承中瓷都高校之作用浅析

在产业化大生产以及现代社会追求速食经济的双重影响之下,融合传统手工制瓷工序和传统陶瓷文化的作品已难得一见,对陶瓷非物质文化遗产的保护传承已经迫在眉睫。经过多年教育改革和发展的景德镇地区高校对于保护和传承陶瓷非物质文化遗产具有重要意义,理应有所作为。     

Generation of a mid-infrared broadband polarized supercontinuum in As₂Se₃ photonic crystal fibers

A simplified structure of birefringent chalcogenide As 2 Se 3 photonic crystal fiber(PCF) is designed.Properties of birefringence,polarization extinction ratio,chromatic dispersion,nonlinear coefficient,and transmission are studied by using the multipole method,the finite-difference beam propagation method,and the adaptive split-step Fourier method.Considering that the zero dispersion wavelength of our proposed fiber is about 4 μm,we have analysed the mechanism of spectral broadening in PCFs with different pitches in detail,with femtosecond pulses at a wavelength of 4 μm as the pump pulses.Especially,mid-infrared broadband polarized supercontinuums are obtained in a 3-cm PCF with an optimal pitch of 2 μm.Their spectral width at 20 dB reaches up to 12 μm.In the birefringent PCF,we find that the supercontinuum generation changes with the pump alignment angle.Research results show that no coupling between eigenpolarization modes are observed at the maximum average power(i.e.,37 mW),which indicates that the polarization state is well maintained.     

管道升压回路的压力控制研究

随着油田开采深度的加深，开采环境不断恶化，这就对于陆上试验系统提出了新的要求，必须考虑其高温高压的工作环境，而如何实现这一环境也一直是各研究机构不断研究的课题。该文从如何对容器进行加压、保压以及稳压方法进行了分析研究，通过试验证明该系统可以达到预先所设想的要求，对加压系统的研究具有很强的借鉴意义。     

某型飞机团修理厂战时维修保障能力分析

以某一次战斗为例，以从团修理厂维修保障工作开始至结束为假设，根据战场实际需要的维修保障能力指数随着时间的变化和团修理厂实际能够提供的维修保障能力指数供需之间的关系，分析某型飞机团修理厂战时维修保障能力的规律。在基本参数定义和条件假设的基础上．建立了团修理厂战时维修保障能力模型，从而提出了两种可以提高团修理厂战时维修保障能力的方法。     

基于DWarf的语义压缩数据方体计算研究

提出了一个可以减少磁盘访问次数的快速Dwarf计算算法Q-Dwarf,避免了在构建Dwarf过程中,计算汇总单元时不必要关闭结点的频繁I/O磁盘访问,节省了时间.并在此结构上构建查询算法以及增量维护算法.实验证明了一系列算法的效率和有效性,尤其适合数据仓库中的高维数据集.     

基于Lyot型光纤消偏器的理论研究

从理论上严格地分析了Ｌｙｏｔ型光纤消偏器的特性，推导出其偏振度与相应变量之间的函数关系．详细地讨论了影响消偏器的偏振残余度的各因素，为实际制作Ｌｙｏｔ型光纤消偏器的工作提供了理论指导。     

浅谈居住区绿地规划与养护管理

从居住区绿地规划的重要性出发，针对居住区公共绿地、宅旁绿地、道路绿地，水景绿化等提出了一些建设性、操作性强的规划设计方案，并对居住区绿地的养护管理提出了合理的建议。     

偏光干涉对光纤陀螺性能的影响

从光纤陀螺光学系统缺陷角度,研究了由于光纤陀螺保偏光纤融接误差及光学器件的不完善引起的偏光干涉效应,理论分析并实验研究了偏光干涉效应对传输光谱的影响及其对光纤陀螺性能的影响。研究表明,在当前的技术条件下,偏光干涉效应对光纤陀螺的标度因数影响可以忽略,偏光干涉不影响一般意义下的光源相干长度,但是却导致光源相干特性的变化,反应在相干图上出现了多个干涉衬比度峰值,这会降低宽谱光源的短相干长度特性给光纤陀螺带来的好处,由此也说明不能仅由相干长度这一个参量描述光源的相干特性。     

关于高炉寿命问题的思考

文章对高炉寿命的问题进行了探讨，指出要保障高炉长寿必须选用适宜的耐火材料及优良的冷却设备，严把施工质量关，加强生产操作和管理，完善对高炉的监测环节。