Generation of 131 fs mode-locked pulses from 2.8μm Er:ZBLAN fiber laser

We demonstrated a femtosecond mode-locked Er:Zr F4-Ba F2-La F3-Al F3-Na F(Er:ZBLAN)fiber laser at 2.8μm based on the nonlinear polarization rotation technique.The laser generated an average output power of 317 m W with a repetition rate of 107 MHz and pulse duration as short as 131 fs.To the best of our knowledge,this is the shortest pulse generated directly from a mid-infrared mode-locked Er:ZBLAN fiber laser to date.Numerical simulation and experimental results confirm that reducing the gain fiber length is an effective way to shorten the mode-locked pulse duration in the Er:ZBLAN fiber laser.The work takes an important step towards sub-100-fs mid-infrared pulse generation from mode-locked Er:ZBLAN fiber lasers.     

Study on the Sensitization of Ce3+ to Nd3+ in YAIO3

This paper presents the absorption spectra, excited spectra and fluorescence spectra of Nd: YAP, Ce: YAP and Nd, Ce: YAP. It is believed that there is an energy transfer from Ce³⁺ to Nd³⁺ and it is possible to improve the laser efficiency of Nd: YAP sensitized by Ce³⁺.     

A KIND OF FLUORESCENCE PROBE TO STUDY THE KINETICS OF POLYMERIZATION PROCESS

Fluorescence properties of 1-pheny1-3-(4'-nitrophenyl) pyrazoline (PNP) were studied inbulk polymerization process of methylmethacrylate (MMA). The fluorescence intensity of PNPwas enhanced and the emission maximum was blue shifted with the polymerization progress. Inthe period of auto-acceleration of the polymerization the enhancement of fluorescence intensityand blue shift of peak wavelength in spectra could be observed evidently. This means that thesolvatochromic properties of PNP are influenced not only by the solvent polarity but also by theviscosity of the medium (especially by the phase transitiott). In solid state PNP emits from thecharge transfer excited state without solvent relaxation. The transient emission spectra and theresults from Bakhshiev model of solvent relaxation coincide with that from the polymerizationexperiment.     

In situ scanning FTIR microscopy and IR imaging of Pt electrode surface towards CO adsorption

In situ scanning FTIR microscopy was built up for the first time in the present work, which consists of an FTIR apparatus, an IR microscope, an X-Y mapping stage, and the specially designed electrochemical IR cell and computer software. It has been demonstrated that this new space-resolvd in situ IR technique can be used to study vibration properties of micro-area, and to perform IR imaging of electrode surface. The chemical image obtained using this technique fur CO adsorption on Pt electrode illustrated, at a space-resolution of 10~(-2) cm, the inhomogeneity and the distribution of reactivity of micro-area of electrode surface.     

反应气中的湿度对Au/Co_3O_4室温催化氧化甲醛的影响

采用共沉淀法制备了Au/Co_3O_4催化剂,通过TG-DSC、XRD、BET、XPS等技术对其进行了表征,并考察了其室温下催化氧化甲醛的性能.结果表明,Au的负载降低了Co3O4催化氧化甲醛的反应温度,在25℃具有60%的催化去除效率(RH 0%,GHSV 80 000 h-1)和100%的CO2选择性;室内环境湿度水平的水汽能显著提高其催化活性,在25℃达到了95%以上的甲醛去除效率(RH 50%,GHSV 80 000 h~(-1))和100%的CO_2选择性,活性持续2 0 h以上未见降低.XPS结果表明,Au在Co_3O_4表面主要以金属单质形式存在,其引入提高了催化剂表面的Oads/Olatt比.原位红外(In situ DRIFTS)分析结果表明,甲酸盐和二氧亚甲基(DOM)是催化反应过程中的主要中间物种,水汽的引入有利于促进甲酸盐的生成、中间产物的氧化分解以及产物的脱附.     

(*)-serial Incidence代数(英文)

设K是一个代数闭域,A是域K上一个有限维代数.我们利用箭图方法给出了(*)-serial incidence代数的分类.     

投资连结型寿险的初始准备金和定价

利用VaR思想并根据保险人风险收益,在初始准备金收益率固定或随机的情况下,讨论了具有养老金性质的投资连结保单的初始准备金和定价,并进行了模拟计算.     

High efficiency top-emitting white organic light-emitting devices with a (metal/organic)2 cathode

White top-emitting organic light-emitting devices (TEOLEDs) were fabricated on a glass substrate with metal/organic multilayer of (Ag/Alq₃)₂ (Alq₃ is tris-(8-hydroxyquinoline) aluminum) as cathode. White TEOLEDs with high efficiency were obtained due to the microcavity effects. And the (Ag/Alq₃)₂ cathode, which adjusted the optical characteristics of the devices, played an important role. In addition, Alq₃–Ag–Alq₃ multilayer could work as a buffer layer, which would simplify the process of encapsulation for devices. We also calculated the electroluminescence spectrum of devices encapsulated with Al₂O₃ (150 nm) and Al₂O₃(75 nm)/ZrO₂(75 nm). And the results indicated that the CIE coordinates is almost the same between with and without encapsulating.     

近自然彩色图像融合算法及其实时处理系统的发展

在军事和生产领域,特别是在极其恶劣的可视条件下,图像融合技术越来越强调融合效果显示的"近自然"感觉,以及人类视觉感知的要求。从彩色图像融合算法的发展概况出发,着重介绍了两种具有代表性的基于视觉特性的近自然彩色图像融合方法,并特别阐述了课题组近期开展的相关算法研究成果。总结了国内外实时彩色图像融合系统的发展现状,概括了课题组已具备的硬件实验基础,综合分析了实时彩色图像融合技术的若干关键技术,如多源图像特征分析、实时图像配准、融合图像后处理等。针对实时图像融合技术的应用状况,提出图像融合系统未来的发展趋势。     

便携式条形码阅读器的设计

本设计为一种便携式条形码阅读译码器（简称阅读器），它采用ＩＮＴＥＬ８０３１ＣＰＵ微处理器为主芯片，辅以其它大规模集成电路芯片，构成一智能化系统，阅读及识别采用Ｃｏｄｅ３９码编制的条形码，并能完成条形码信息的存储、数目统计及与微机进行串行通信功能。