分光光度法测定饮料食品中痕量有机锗和无机锗的研究

本文研究了在溴化十六烷基三甲基铵（ＣＴＭＡＢ）抗坏血酸（Ｖｃ）存在下，苯基荧光酮（Ｐｆ）光度法测定痕量锗的最佳实验条件及配合物的组成，从而建立了测定痕是锗的新方法，其方法的灵敏度ε＝１．０３４×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１锗含量在０－１６．８μｇ／２５ｍＬ范围内符合比耳定律，稳定性好，操作简便，快速。应用本法测定了矿泉水，茉莉花茶，大蒜中有机锗和无机锗的含量，回收率在９１．６％－１０３．５     

原子吸收光谱法测定有机锗（Ge─132）中的锗及其杂质

火焰原子吸收法测定有机锗（Ｇｅ．１３２）①中的锗，线性浓度范围为０－１．２５ｍｇ／ｍＬ，方法精度为１．２％，相对标准偏差＜２％，平均回收率为９９．５％。杂质Ｐｂ和Ａｓ用塞曼石墨炉原子吸收测定，Ｐｂ用（ＮＨ_４）_２ＨＰＯ_４＋Ｍｇ作改进剂，Ａｓ用Ｐｄ作改进剂，特征质量分别为８．２ｐｇ和８ｐｇ，相对标准偏差分别为２．１％和２．２％，并讨论了有关机理问题。     

原子吸收光谱法测定有机锗（Ge—132）中的锗及其杂质

火焰原子吸收法测定有机锗（Ｇｅ－１３２）中的锗，线性浓度范围为０－１．２５ｍｇ／ｍＬ，方法精度为１．２％，相对标准偏差〉２％，平均回收率为９９．５％，杂质Ｐｂ和Ａｓ用塞曼石墨炉原子吸收测定，Ｐｂ用（ＮＨ４）２ＨＰＯ４＋Ｍｇ作改进剂，Ａｓ用Ｐｄ作改进剂，特征质量分别为８．２ｐｇ和８ｐｇ，相对标准偏差分别为２．１％和２．２％，并讨论了有关机理问题。     

食品中无机锗与锗—132的分别测定

采用氢化物发生－原子荧光光谱法（ＨＧ－ＡＦＳ），分别测定了保健饮品中的无机锗和β－羧乙基锗倍半氧化物（即锗－１３２），同时对于天然食品中无机锗和锗－１３２分别测定的条件也进行了初步的探讨。     

新试剂N-壬基-N′-(氨基对苯磺酸钠)硫脲(NPT)与钯(Ⅱ)显色反应的研究和应用

研究新合成的水溶性光度试剂Ｎ－壬基－Ｎ′－（氨基对苯磺酸钠）硫脲（ＮＰＴ）与钯（Ⅱ）的显色反应，结果表明，在ｐＨ５．８～６．６的ＨＡｃ－ＮａＡｃ缓冲体系中，Ｐｄ２＋与ＮＰＴ形成１４的黄色水溶性配合后物，ＣＴＭＡＢ对反应有明显的增敏作用，配合物的最大吸收波长位于２９７．６ｎｍ，表观摩尔吸光系数ε２９７．６＝１．２７×１０５Ｌｍｏｌ－１ｃｍ－１，钯含量在２～１１．２μｇ／２５ｍＬ范围内服从比尔定律，５０种离子不干扰测定，其灵敏度和选择性是目前测钯（Ⅱ）的最好的试剂之一。该法用于阳极泥和催化剂中钯的测定，均获满意结果。     

石墨炉原子吸收法测定麦芽粉中的锗和硒

本文叙述了平台石墨炉原子吸收法测定麦芽粉中的锗和硒，采用Ｐｄ＋Ｎｉ和Ｐｄ基体改进剂，使锗和硒的灰化温度分别提高到１４００和１２００℃，有效地消除了基体干扰。方法特征量为３１ｐｇ（Ｇｅ）和２３ｐｇ（Ｓｅ），检出限为２８ｐｇＧｅ和６２ｐｇＳｅ（３σ）。对含２２￣１１０μｇ／ｇＧｅ和１８￣３５μｇ／ｇＳｅ的样品测定，相对标准偏差为Ｇｅ３．７￣５．６％（ｎ＝９），Ｓｅ４．３￣６．５％（ｎ＝９），回收率在９     

正丁醇萃取石墨炉原子吸收法测定微量锗

建立了萃取－石墨炉原子吸收法测定中草药、植物样品及水系沉积物中微量锗的方法。锗与钼酸铵在０．３ｍｏｌ／Ｌ的硝酸介质中，可以生成稳定的锗钼杂多酸盐，并能被正丁醇萃取，有机相直接进样测定。本方法采用钼酸铵浸渍处理石墨管，直接测定了枸杞、蕨麻等植物样品及水系沉积物中的微量锗。方法的检出限为６．０×１０（－１２）ｇ，对于３０ｎｇ／ｍＬ锗的测定相对标准偏差为５．０％     

石墨炉原子吸收法测定玉米中镉

本文研究了石墨炉原子吸收法测定玉米中镉的方法。用聚四氟乙烯高压消化弹溶解样品，用金属钯做基体改进剂和李沃夫平台石墨管提高方法的灵敏度。用本法测定镉的检出限为０．１２ｐｐｂ，相对标准偏差为２．６６％（ｎ＝１１），方法的回收率为９７％－１０５％之间。     

火焰原子吸收光谱测定微量锗的研究

本文研究了空气－乙炔火焰原子吸收分光光度法测定饮料及灵芝酒中微量金属元素锗。该法线性范围宽（５０－３００μｇ／ｍｌ），选择性强，并有良好的精密度和准确度。样品加标回收率为９７．９－１０３．４％，变异系数１．４％。本方法适用于保健滋补饮品中锗的分析。     

新试剂N-已基-N′-(氨基对苯磺酸钠)硫脲(HXPT)的合成及其测定微量钯的研究

合成了新试剂Ｎ－已基－Ｎ′－（对苯磺酸钠）硫脲（ＨＸＰＴ）并确定了其结构。研究了它与钯（Ⅱ）反应的条件试验,结果表明,在ｐＨ ５．４～５．８ 的ＨＡｃ－ＮａＡｃ介质中,有溴化十六烷基三甲胺（ＣＴＭＡＢ）的存在,试剂与钯（Ⅱ）形成稳定的黄色配合物,最大吸收波长为２９６．８ ｎｍ ,表观摩尔吸光系数为２．２１×１０５ Ｌ·ｍ ｏｌ－ １ ·ｃｍ － １,钯浓度在１～７ μｇ·２５ ｍ Ｌ－ １ 范围内,符合比尔定律。方法简便、快速、选择性好,用于催化剂、矿样中微量钯的测定,结果满意。     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Characterization of PolyA and PolyC mismatches by Raman spectroscopy

A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.     

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.     

Multi-pulse operation of a Kerr-lens mode-locked femtosecond laser

Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.     

Propagation of Helmholtz-Gauss beams in weak turbulent atmosphere

Based on the Rytov approximation of light propagation in weak turbulent atmosphere,the closed-form expressions of field and average irradiance of each one of the four fundamental families of Helmholtz-Gauss (HzG)beams:cosine-Gauss beams,stationary Mathieu-Gauss beams,stationary parabolic-Gauss beams,and Bessel-Gauss beams,which are propagating in weak turbulent atmosphere,are obtained.The results show that the field and average irradiance can be written as the product of four factors:complex amplitude depending on the z-coordinate only,a Ganssian beam.a factor of complex phase perturbation induced by atmospheric turbulence,and a complex scaled version of the transverse shape of the non-diffracting beam.The effect of weak atmospheric turbulence on irradiance distribution of the HzG beam can be ignored.     

An effective method for reducing speckle noise in digital holography

An effective method for reducing the speckle noise in digital holography is proposed in this paper.Different from the methods based on classical filtering technique,it utilizes the multiple holograms which are generated by rotating the illuminating light continuously.The intensity images reconstructed by a series of holograms generated by rotating the illuminating light possess different speckle patterns.Hence by properly averaging the reconstructed intensity fields,the speckle noises can be reduced greatly.Experimental results show that the proposed method is simple and effective to reduce speckle noise in digital holography.     

Influence of purity of HfO2 on reflectance of ultraviolet multilayer

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry(SIMS) equipment respectively.It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films.In addition,the difference of Zr content in the two kinds of HfO2 single laver films was much laxger than that of the other impurities such as Ti and Fe.which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2.With these two kinds of HfO2 and the same kind of SiO2.we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm.Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively,which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.     

Speech enhancement by array crosstalk resistant ANC and spectrum subtraction

Microphone array-based speech enhancement has great importance for speech communications and speech recognition. To reduce the aperture of the microphone array and to increase the effect of the speech enhancement will greatly broaden the application areas of the microphone array. An array crosstalk resistant adaptive noise cancellation method is therefore presented. And then an improved spectral subtraction algorithm is further cascaded to obtain better enhancement results. Theoretic analysis and experiments indicate that the proposed scheme needs only a very small microphone array while it simultaneously achieves a higher SNR improvement. Besides, the proposed scheme can be used in many noisy environments and is easy for real-time implementation.