基于激光瞬态特性的气体浓度光纤传感器

报道了一种基于掺铒光纤激光器瞬态特性的新型气体浓度传感器.用光纤环全反镜和光纤Bragg光栅(FBG)构成F-P线形腔，通过调节光栅的反射波长，使激光激射波长落在C₂H₂的一个较强的吸收峰1531.56 nm.激光激射延迟时间与激光器谐振腔损耗密切相关，气体浓度的改变将引起谐振腔损耗的改变，通过测量激光激射延迟时间可以获得气体的浓度.该装置分辨率及灵敏度由抽运光脉冲的高功率电平和低功率电平决定，传感器的动态测量范围由抽运光高功率电平决定.当高功率和低功率电平分别为25 mW和5.9 mW时,该传感器的灵敏度和分辨率分别为100 ppm/μs和20 ppm.     

疏水性咪唑类混合离子液体的物理化学性质

本文选取疏水性和疏水性离子液体混合物作为研究对象, 将疏水性离子液体1-甲基-3-n-丁基咪唑三氟甲基磺酰胺盐[BMImN(CF3SO2)2]与BMImPF6以不同的比例进行混合, 对混合离子液体及其相应单组分离子液体进行了相关物理化学性质的测试和对比, 讨论由于混合导致的物理化学效应.     

飞秒脉冲初始脉宽和啁啾对其自相似演化及压缩的影响

采用自相似抛物脉冲放大器对飞秒脉冲直接进行放大,并以低非线性系数的光子带隙光纤作为脉冲压缩器对放大的脉冲进行压缩.通过分步傅里叶方法研究了飞秒脉冲的初始宽度和啁啾对其自相似演化和压缩的影响.研究结果表明脉冲宽度越宽,脉冲自相似演化程度越差,演化脉冲的压缩质量也越差,压缩脉冲宽度较大,且有基座;脉冲的初始啁啾会严重阻碍其自相似演化,并最终影响脉冲的压缩质量;啁啾越大,脉冲的自相似演化结果越差,脉冲的压缩质量也越差;正的啁啾对脉冲的自相似演化的影响比负啁啾的要大.     

Photon pair generation in lithium niobate waveguide periodically poled by femtosecond laser

Reliable generation of single photons is of key importance for fundamental physical experiments and quantum protocols.The periodically poled lithium niobate [LN) waveguide has shown promise for an integrated quantum source due to its large spectral tunability and high efficiency, benefiting from the quasi-phase-matching. Here we demonstrate photon-pair sources based on an LN waveguide periodically poled by a tightly focused femtosecond laser beam. The pair coincidence rate reaches ～8000 counts p...     

Two-Photon Interference Constructed by Two Hong–Ou–Mandel Effects in One Mach-Zehnder Interferometer

We present a two-photon interference experiment in a modified Mach-Zehnder(MZ) interferometer in which two Hong–Ou–Mandel effects occur in tandem and construct superposed two-photon states. The signal photons pass both the arms of the MZ interferometer while the idler photons pass one arm only. Interestingly, the probability of the idler photons emerging from any output port still shows a sine oscillation with the two-photon phase difference and it can be characterized only by the indistinguishability of the two-photon amplitudes. We also observe a two-photon interference pattern with a period being equal to the wavelength of the parametric photons instead of the two-photon photonic de Broglie wavelength due to the presence of two-photon phase difference, in particular, with complementary probabilities of finding the two-photon pairs in two output ports. The abundant observations can facilitate a more comprehensive understanding of the two-photon interference.     

基于演化博弈的垃圾分类管理策略研究

国内外研究经验表明，垃圾分类是缓解环境问题的重要举措。但是现行的垃圾分类激励机制存在居民负担重、推广阻力大等问题。本文提出将垃圾分类所得绿色积分与碳交易机制相结合的新型激励机制，并应用演化博弈理论建立了政府、企业与居民之间的三方非合作博弈模型，最终通过数值模拟量化分析关键参数对三方主体决策的影响。结果表明：(1)最终的演化均衡结果是：政府选择本文设计的垃圾分类积分机制、企业选择激进生产、居民选择执行垃圾分类；(2)通过数值模拟得出：(1)在积分机制下，政府可以通过增加10%以内的宣传监管投入或40%以内的企业补贴来推进演化过程；(2)居民的积分收益减少在30%以内、时间与体力支出增加在15%以内，仍应执行垃圾分类；(3)企业的额外产值收益减少在10%以内、积分价格增加在75%以内，仍会采取激进生产。因此，本文提出的积分机制相较于现行机制更具优势，有望为我国生活垃圾分类机制建设与循环经济发展提供决策支持。     

线型缩聚反应的计算机模拟

缩聚反应是一类重要的高分子合成方法。其中最简单的反应为线型缩聚体系,它可分为两类,分别是含有两个可缩合的官能团的单体或单体对进行的相互缩合的体系。Flory在上世纪四十年代采用统计方法对该缩聚体系做过系统的理论研究,并在官能团等活性的假定下提出了著名的Flory分布函数,由此揭示了反应体系中数均聚合度xn、重均聚合度xw、不同聚合度分子的分布情况与反应程度p的关系。本文利用计算机模拟的方法,同样在官能团等活性的假定下模拟了线性缩聚反应的全反应过程,所得到的结果与用统计方法所得到的结果完全一致。本方法是对整个真实反应过程的直观模拟,对研究相似的以逐步聚合反应机理进行的反应具有普适性,并具有可拓展到模拟更真实的粘性聚合体系以及研究反应动力学的潜力。     

Effects of 5 Meson on Thermal Protoneutron Star Matter

In the framework of the relativistic mean field theory, the effects of the 6 meson on protoneutron star matter with hyperons at finite temperature are investigated. In thermal protoneutron star matter, the 6 field potential increases with density first and then decreases. Fixing the density, the increase of the temperature suppresses the 6 field potential. With the inclusion of the 6 meson, the threshold densities for hyperons become lower and the abundance of trapped neutrinos decreases. The most important effect of the 6 meson is to increase the abundance of hyperons in the inner core range of protoneutron stars. With the rise of the temperature, the density range where the 6 meson plays an important role is narrowed and the effects of the 6 meson are suppressed. Moreover, the protoneutron star mass and radius are nearly not affected by the 6 meson.     

φ-强伪压缩映象隐迭代过程的收敛性分析

在任意Banach空间讨论了有限个φ-强伪压缩映射族隐迭代过程的收敛性问题.利用φ的性质和迭代过程本身的特性,得到了隐迭代过程收敛于公共不动点的若干结果.这些结果补充和推广了过去的研究成果.因此它丰富和发展了隐迭代法的理论.     

Characteristics of Solid State Cathodoluminescence of PPV

Based on our previous discovery [Chem.Phys.Lett.325(2000)420] of the solid-state cathodoluminescence from organic luminescent materials in inorganic/organic heterojunction,we study characteristics of this new kind of electric-field-induced luminesecence by means of examining its oscillogram.We prepared three devices with differect structures in which PPV was used as luminescent layer,and SiO2 was used as accelerating layer.The experimental results might be understood only by means of the existence of solid-state cathodoluminescence.This new kind of luminescence makes it possible to produce new type of flat panel display.