直接荧光法和流动注射荧光法测定微量氨的研究

在碱性介质中 ,基于氨与邻苯二甲醛及 2 巯基乙醇反应生成强荧光性吲哚取代衍生物的体系建立测定水溶液中微量氨的直接荧光法和流动注射荧光法。曲通X 10 0 (TritonX 10 0 )对该体系具有良好的增稳作用。在λex=4 15nm ,λem=4 86nm下 ,用直接荧光法测定NH3含量在 0 2～ 1 0 μg·mL- 1 范围内 ,工作曲线的回归方程为ΔI =2 2 2 86 785 71cNH3(μg·mL- 1 ) (I即为Intensity) ,r=0 9995 ;NH3含量在 0 0 2～ 0 10 μg·mL- 1 范围内 ,工作曲线的回归方程为ΔI=- 2 7 4 2 9 2 371 4cNH3(μg·mL- 1 ) ,r=0 996 5。用流动注射法测定的工作曲线的回归方程为ΔI=1188cNH3(μg·mL- 1 ) ,r=0 9998,线性范围为 0～ 0 7μg·mL- 1 ,并对反应机理进行初步探讨。     

Facile controlled synthesis of micro/nanostructure MCrO4 (M = Ba, Pb) by using Gemini surfactant C12-PEG-C12 as a soft template

Gemini surfactants, double sodium α-sulfonic polyethylene glycol laurate (abbreviated C₁₂-PEG-C₁₂), were prepared and applied as soft templates in the controlled synthesis of BaCrO₄ and PbCrO₄ micro/nanocrystals. The template effects were investigated by adjusting the length of the spacer, using PEG400 and PEG4000, of the Gemini surfactant. The results indicated that the size and morphology of BaCrO₄ and PbCrO₄ micro/nanocrystals varied with the change in spacer length of C₁₂-PEG-C₁₂, suggesting that the different lengths of the polyethylene glycol group spacers in the Gemini surfactants played a key role in determining the size and shape of the MCrO₄ micro/nanoparticles. The dynamic process of the formation of the novel morphology BaCrO₄ crystals showed that the morphology grew from a round-bar polyhedron, to regular polyhedron, to approximate octahedron to a uniform pistachio nut shape. The growth mechanism of the BaCrO₄ micro/nanocrystals was explained that C₁₂-PEG-C₁₂ had a greater interfacial adsorption and would effectively control the shape evolution during the crystal growth, while PbCrO₄ could be explained that the Gemini surfactants can undergo liquid-crystalline phase transitions with long channels providing a soft template effect and derived the nanorods formation. Room temperature fluorescence spectra were studied and these showed that the pistachio-shaped BaCrO₄ microcrystals and PbCrO₄ nanorods possess photoactive luminescence properties with emission peaks at 470 and 549 nm, respectively.     

Scheme for the implementation of 1→3 optimal phase-covariant quantum cloning in ion-trap systems

This paper proposes a scheme for the implementation of 1→ 3 optimal phase-covariant quantum cloning with trapped ions. In the present protocol, the required time for the whole procedure is short due to the resonant interaction, which is important in view of decoherence. Furthermore, the scheme is feasible based on current technologies.     

频闪及Matlab技术验证机械能守恒实验装置

利用摄像头频闪技术及Matlab软件组装了一个利用单摆验证机械能守恒的实验装置,主要解决学生在缺乏打点计时器的情况下,利用简便设备进行探究的难题,并将验证推广到二维.利用数据采集量大的优点,解决了传统实验只能验证机械能相等而不能验证机械能守恒的问题.     

Diffraction grating single-shot correlation system for measurement of picosecond laser pulses

We study and experimentally demonstrate a sensitive single-shot correlation system in which only a diffraction grating is used to produce a transverse time delay (TTD) in the reference pulse.The mechanism of the TTD introduced by the grating and the formation of the relative time delay (RTD) in the noncollinear correlation system are analyzed in detail.By using our system,we successfully measured the temporal duration of picosecond laser pulses,and a time resolution of ～0.047 ps is obtained at 1047 nm.The impact of the grating dispersion and the second harmonic beam walk-off effect on the measurement are considered.     

分光计测定光栅常数

针对分光计测定光栅常数实验中入射光线偏离光栅法线的情形,提出了计算光栅常数的一个近似表达式。在不增加额外测量的前提下,使实验结果更接近于实际值。     

分辨率对大气中痕量污染气体的DOAS测量性能影响研究

在差分吸收光谱(DOAS)测量过程中,光谱分辨率的选择直接决定了污染气体浓度的测量准确度.主要研究了光谱分辨率对污染气体被榆测到的特征吸收结构形状的影响,以及差分吸收截面随分辨率的变化趋势,从而确定了光谱分辨率对污染气体最低可检测浓度的影响,通过研究分辨率与光强的关系,确定了分辨率与信噪比(S/N)的函数关系式,得出了DOAS测量NO2,O3,和SO2的最佳信噪比范围,对多种污染物标准气体进行了同时监测,计算出标准气体在不同光谱分辨率下的测量误差,确定了对NO2,O3和SO2监测的最适用的分辨率范围.在此分辨率范围既能够实现对痕量气体的准确定性定量测量,又能达到测量所需要的高灵敏度,强选择性和适用的时间分辨率.通过在北京丰台区的实际监测得到了与点式仪器测量结果很好的一致性.     

Fluorescent Triphenyl Substituted Maleimide Derivatives: Synthesis,Spectroscopy and Quantum Chemical Calculations

In this paper we describe a semi-empirical quantum method for predicting the wavelength of maximum fluorescence excitation and emission for several known and new maleimide derivatives. All new maleimides, containing a N-Benzyl attachment, were successfully synthesised via a tandem Suzuki reaction with aryl boronic acids containing either an electron donating, electron withdrawing functional groups. Absorption and emission spectra calculated using the semi-empirical AM1 method with excited state ZINDO calculations proved more reliable than either Hartree-Fock Configuration interaction or time dependent density functional methods. Calculated absorption and emission wavelengths were compared with 26 experimental spectra from known or newly synthesised maleimides and found to have provide reasonable predictions, with an average deviation of less the 6% for absorption maxima and less than 4% for emission peaks. The described method provides a strong benchmark for the accuracy that can be expected from theoretical predictions of fluorescence spectra.     

Micro-FTIR study on structure of macerals from Jurassic coals in Northwestern China

Jurassic coal in Northwest China is rich in resources and it is a necessary premise to reveal the chemical structure characteristics of the coal macerals in this region before the coal is put into reasonable and efficient use. Micro-FTIR technique was used to investigate the chemical composition and structures of vitrinite semifusinite and fusinite from Jurassic coal in Northwestern China. The results show that vitrinite and semifusinite have more aliphatic hydrogen, but fusinite has more aromatic hydrogen and C=O structure. The aliphatic hydrogen in semifusinite is higher than that in fusinite and it is this structure characteristic of semifusinite that led to the richer inertinite but higher reactivity of the Northwestern China coal. Not only vitrinite but also semifusinite and fusinite with weaker reducibility have less aliphatic hydrogen and more C=O structures than those with stronger reducibility. The different intensity of oxidation in the process of coalification is one of the causes that led to different type of reducibility.     

Investigation of the influence of extra noises in seed beams on continuous-variable entanglement generation

The influence of the extra classical noises in seed beams on the entanglement between the signal and the idler modes of the output fields generated by a non-degenerate optical parametric amplifier operating at deamplification is investigated theoretically and experimentally.With the increase of the extra classical noises in the seed beams,the correlation degree of the output entangled optical fields,which is scaled by the quantum noise limit,decreases rapidly.The experimental results are in good agreement with the theoretical calculations.