343 nm飞秒激光制备微孔阵列以增强聚氨酯合成革透湿性

为了提高聚氨酯(PU)合成革透湿性,分别使用343 nm飞秒激光和作为对比的1030 nm飞秒激光及1064 nm纳秒激光制备微孔阵列。采用扫描电镜(SEM)和3D激光扫描显微镜对比研究了微孔形貌。结果表明,343 nm飞秒激光可以制备出效果最佳的微孔。此外,分析了3种激光与PU涂层的作用机理,揭示了343 nm飞秒激光合成革微钻孔过程仅表现为光化学烧蚀,光化学和光热烧蚀同时发生于1030 nm飞秒激光钻孔过程,而1064 nm纳秒激光只显示了光热烧蚀。激光合成革表面钻孔后,测量其透湿性和抗张力。结果显示: 微孔密度越大,皮革透湿性(WVP)越大而抗张力越低,脉冲重叠的增加会导致WVP的增加和抗张力的下降;同时,随着脉冲重叠从91.7%降到50%,微孔直径从45 μm降低到30 μm,而微孔锥度从0.7°增加到12.1°;当脉冲重叠率为91.7%,微孔密度为2550/cm²时,最大的WVP增长率为306%。     

A mini-review on econophysics:Comparative study of Chinese and western financial markets

We present a review of our recent research in econophysics, and focus on the comparative study of Chinese and western financial markets. By virtue of concepts and methods in statistical physics, we investigate the time correlations and spatial structure of financial markets based on empirical high-frequency data. We discover that the Chinese stock market shares common basic properties with the western stock markets, such as the fat-tail probability distribution of price returns, the long-range auto-correlation of volatilities, and the persistence probability of volatilities, while it exhibits very different higher-order time correlations of price returns and volatilities, spatial correlations of individual stock prices, and large-fluctuation dynamic behaviors. Furthermore, multi-agent-based models are developed to simulate the microscopic interaction and dynamic evolution of the stock markets.     

基于线阵探测器的单圈绝对轴角编码器

为了解决轴角编码器尺寸与角度分辨率之间的矛盾,同时提高编码器的响应频率,提出了一种基于线阵探测器的单圈绝对式光电轴角编码器.该编码器使用了一种新型单圈绝对式编码盘,整个码盘只有一个码道,粗码被直接刻在这个单圈的码道上,码盘图像经光学放大后被线阵探测器接收.利用FPGA控制电路将数据传送至计算机,并对数据进行译码处理,分别利用图像处理技术读取粗码和利用像素细分技术获得细码,两者相结合得到角度信息.通过该技术设计一个码盘直径为40 mm的绝对式轴角编码器,其分辨率为15位.     

Influence of the retardation of the multiplexing element in a dual channel Q-switched laser

We present an experimental and numerical analysis, how deviations of the multiplexer-retardation influence the output power of a time-multiplexed dual channel laser. The laser has two different channels, each one with its own gain medium. The channels are time-multiplexed by a single crystal photo-elastic modulator. It enables to double the repetition rate and output power of the laser. However, as multiplexing is based on polarization-switching, the retardation of the modulator should be kept within certain limits. By experimental measurement and theoretical analysis, we determine the operational window within which the retardation should be kept to avoid additional losses into the resonator. The analysis was done for two configurations of the laser setup, namely with and without a quarter-wave plate.     

GC-FTIR和GC-MS联用在环状硫代碳酸酯混合物中的应用

采用GC-FTIR和GC-MS建立环状硫代碳酸酯和环状碳酸酯的分析方法.选用HP-5毛细管色谱柱(30m×320μm×0.25μm),分流比50∶1,进样量1μL,进样口起始温度120C,保持5min,升温速率15℃/min,进样口终止温度270℃.质谱采用EI源,选取Scan模式,扫描范围为50到550m/Z.结果表明GC-FTIR可鉴定出3种环状硫代碳酸酯,而GC-MS可同时鉴定出4种环状硫代碳酸酯.     

Toroidal,compression, and vortical dipole strengths in 144-154Sm: Skyrme-RPA exploration of the deformation effect

All transfer reactions and radiative capture nuclear-astrophysical reactions at low energies measured so far are analysed using a reaction theory that contains overlap functions between the wave functions of the target and residual nuclei. These overlaps are assumed to have an asymptotic form determined by the separation energy of the transferred (or radiative captured) cluster and such an assumption is incorporated into all reaction codes. We point out that although this asymptotic form is dominant for the majority of the transfer reactions and the nuclear-astrophysical radiative capture reactions, for some cases the overlap function has anomalous asymptotic behavior. This behavior originates from virtual decays of the complex nucleus into intermediate channels and, mathematically, is generated by contributions from the singularities of the triangle Feynman diagram and the generalised triangle diagram containing a loop. In the present work, these contributions are investigated in detail and expressions are derived for the strengths of the anomalous terms taking spin variables and the Coulomb effects into account. We present specific examples of nuclear vertices with anomalous asymptotics and discuss their application for peripheral nuclear processes.     

近红外光谱相关系数法用于快速检测药品的质量

对近红外光谱相关系数法检测药品质量变化的效果进行了研究,并考察了相关系数方法对同一品种药品来自不同厂家生产的样品的区分能力进行了计算,还研究了在不同仪器上、由不同人员测定光谱时相关系数方法的识别能力。本文还对计算相关系数时的光谱预处理方法和谱段等参数进行了探讨,提供了建议性的参数条件,为近红外光谱相关系数方法用于药品质量快速分析提供参考。     

Photoinduced charge injection in the metal/organic interface studied by transient photovoltage measurements with bias

Transient photovoltage of ITO/organic/Al cells is studied under different bias polarities and voltages.It is found that for an ITO/NPB/Al cell,light incidence on the Al side induces more bias-dependent transient photovoltage variation when the photovoltage is positive than when it is negative.However,for an ITO/C60 /Al cell,the variation characteristics of transient photovoltage is reversed.These results support the previously proposed mechanism that Al could inject charges into the organic layer upon photon excitation,indicating that the absorption of electrode can also contribute to photovoltaic effect.     

光纤化学传感技术研究近况

光纤化学传感器作为传感器的一个重要分支,结合了化学和光学的相关技术,将化学制膜、光纤技术以及化学分析中的分光光度法、拉曼光谱、荧光光谱、折射率检测等方法相融合,以其微型化,抗电磁干扰,传输信息量大,拥有自身参比等特点不断向前发展。简要综述了光纤化学传感技术研究近况和未来的发展趋势。重点对光纤pH化学传感器、光纤离子化学传感器和光纤气体化学传感器进行了介绍。简要分析了常见的敏感膜制备方法如化学键合法和溶胶凝胶(sol-gel)等方法。新型光纤——微结构光纤的出现为光纤化学传感器开辟了新的发展方向。由于其具有大的内表面积,结构设计灵活多样,光纤内部提供感应场所等特点,快速度成为光纤化学传感器的重要发展方向和研究热点。对微结构光纤衍生而来的新型光纤化学传感器进行了详细评述, 最后对光纤化学传感器的未来进行展望。