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81.
Fluorescence spectroscopic properties of the complex formation between six new C-pivot16-crown-5 ethers bearing fluorescence side arms and metal ions are studied. Six new C-pivot 16-crown-5 ethers that carry fluorescence side arms were synthesized. The research also included the examination of different fluorescent behavior of the new lariat ethers in the presence of silver and sodium ions (Ag+ and Na+) in methanol. Because of the good fit of the cavity size of these 16-crown-5 ethers with the Ag+ and Na+ ions, remarkable change in fluorescent spectra were observed. The results showed that the new lariat crown ethers exhibited enhanced selectivity towards sodium ion, but silver ion show quenching abilities towards the ligands. Cooperative participations of the C-pivot side arm oxygen with the ring oxygen molecules in complexation was also confirmed by the single crystal X-ray crystallography of the complex, (C27H30O7)·NaClO4. The freezing of crown ring conformation and the diminishment of the chance of sidearm oscillation that occurred upon complexation with sodium ion are the main causes of fluorescent enhancement. The quenching caused by the addition of silver ion was found to explainable by the photo-induced electron transfer that results in the reduction of silver ions. 相似文献
82.
C. Teichmann S.A. Buehler 《Journal of Quantitative Spectroscopy & Radiative Transfer》2006,101(1):179-190
This paper presents a simple conceptual model to explain that even spherical scatterers lead to a polarization difference signal for microwave limb radiances. The conceptual model relates the polarization difference measured by a limb-looking sensor situated inside a cloud with the anisotropy of the radiation. In the simulations, it was assumed that the cloud consists of spherical ice particles with a radius of which were situated between 10.6 and 12.3 km altitude. The frequencies 318 and 500 GHz were considered.The results of the conceptual model were compared to the results of the fully polarized scattering model ARTS-1-1. The comparison showed a good qualitative agreement. The polarization difference decreases inside the cloud with increasing height and changes sign. This behavior can be related to a different amount of radiation coming from the atmosphere above and below the cloud, compared to the amount of radiation coming from the sides. The sign of polarization difference of the scattered radiation is opposite for these two radiation sources. 相似文献
83.
84.
双水相体系中镧与钛的分离及光谱性能 总被引:7,自引:0,他引:7
在聚乙二醇-硫酸铵-铬天青S双水相体系中,用铬天青S作萃取剂,研究了La(Ⅲ),Ti(Ⅳ),Zr(Ⅳ)的液-液萃取行为,在pH5.5时,实现了体系中La(Ⅲ)与Ti(Ⅳ)的分离,通过加入表面活性剂测定光谱方法,研究了高聚物相中La(Ⅲ)的存在形态。 相似文献
85.
Sahar Al Akoum-Ebrik Mohamed Ansar Rahima Mouhoub Claude Vaccher Marie-Pierre Vaccher Nathalie Flouquet 《光谱学快报》2013,46(5):925-944
The enantiomeric composition and absolute configuration of 4-Amino-3-(benzo[b]furan-2-yl)-Butanoic Acids and of 4-Amino-3-(thien-2-yl)-Butanoic Acids 1 may be accurately determined by 1H and 13C nuclear magnetic resonance analysis of the corresponding derivatives 3 prepared by reaction with chiral reagents. Correlation with HPLC is signaled. 相似文献
86.
微波消解-氢化物发生-原子荧光法测定海蜇中的痕量砷和硒 总被引:12,自引:2,他引:12
建立了氢化物发生-原子荧光光谱法(HG-AFS)测定新鲜和腌制海蜇中痕量砷、硒的分析方法。采用冷冻干燥和微波消解相结合的方法处理样品,设定了最佳的样品处理条件和仪器测定条件,解决了消解液中过剩酸对测定的干扰问题,并对共存元素干扰情况进行了研究。利用加标回收试验,对分析方法进行了验证。实验结果表明,该方法具有简便、快速、灵敏、准确等特点,适合于含水量较高的生物样品的测定。 相似文献
87.
The gauging of free differential algebras (FDA's) produces gauge field theories containing antisymmetric tensors. The FDA's extend the Cartan-Maurer equations of ordinary Lie algebras by incorporating p-form potentials (p>1). We study here the algebra of FDA transformations. To every p-form in the FDA, we associate an extended Lie derivative l generating a corresponding gauge transformation. The field theory based on the FDA is invariant under these new transformations. This gives geometrical meaning to the antisymmetric tensors. The algebra of Lie derivatives is shown to close and provides the dual formulation of FDA's. 相似文献
88.
单模光纤陀螺正交锁相检测方法的研究 总被引:3,自引:0,他引:3
研究了用于干涉型单模光纤陀螺系统的正交锁相检测方法,采用双参考信号,使输出的信号与噪声分离,不仅提高了光学系统信号的信噪比,同时可以引入移相反馈控制,大大减小了系统的漂移,系统的零点漂移已达到0.2deg/h。 相似文献
89.
S变换是一种集合了窗口傅里叶变换和小波变换优点的时频分析技术,目前一维S变换已成功应用于结构光投影的条纹相位解调中。由于二维S变换可以对图像在两个方向上进行时频分析,具有更优于一维S变换的分析和处理能力。为了完善S变换的条纹相位解调理论,将二维S变换方法引入到基于结构光投影的三维光学测量中,研究了二维S变换在条纹相位解调中的原理及应用,给出了详尽的理论分析,并同一维S变换结果进行了比较。模拟和实验都表明,在条纹图解相中,二维S变换比一维S变换提取的相位精度更高,即使在存在较严重噪声污染的情况下也表现出良好的可靠性,体现出二维S变换提取相位的优势。 相似文献
90.