荧光法直接测定环境水中痕量苯酚

研究了荧光分光光度通过控制酸度直接测定环境水中苯酚的新方法。在pH＝1时，直接测定苯酚的含量，波长为λex／λem＝270／297nm，检出限为4．0g/mL，线性范围为0－3．2μg/mL。回收率为99％－101％。     

铋磷钼蓝分光光度法测定金属硅中磷

本文建立了测定金属硅中磷的方法，检出限为0．0020％，回收率为92％－104％。     

一阶导数分光光度法测定汽油中共轭二烯烃

本文应用共轭双烯在酸性介质中，可以使磷钼酸铵还原成磷钼蓝的反应，建立了测定汽油中共轭双烯烃含量的一阶导数分光光度法。该方法的相对标准偏差≤4．1％，加标回收率为96．2％－105．0％，与气相色谱法进行对照实验，两方法测定结果相吻合。     

ICP—AES法测定复合肥中磷,钾,锌,锰和硼

用ＩＣＰ－ＡＥＳ法同时测定了复合肥中磷，钾锌锰和硼，确定了仪器的工作参数，对分析线的选择，背景扣除。酸度影响和共存元素间的干扰等进行了研究。方法的回收率为９５％－１０４％，相对标准偏差为２．６６％－５．５４％。     

微波消解、流动注射-氢化物发生原子荧光光谱法测定三七中硒含量

用微波消解、流动注射－氢化物发生原子荧光光谱法测定三七中硒，通过实验选择最优化的测定条件，方法的检出限为0．30μg.L^-1，相对标准偏差为1．2％，线性范围为0－100μg.L^-1，相关系数为0．9999，回收率为96．7％－100．7％。     

萃取-磷钼蓝比色法测定镍铬丝中磷

在0．7—1．0mol/L的硝酸介质中^[3]，采用萃取-磷钼蓝比色法测定镍铬丝中的磷，络合物的最大吸收峰位于680nm，测定范围为0．001％-0．05％，相对标准偏差为＜3．8％。     

ICP-AES测定饮用水源中的Cu、Mn、Pb、Cd、Zn

用ICP－AES法同时测定饮用水源中的Cu、Mn、Pb、Cd、Zn等重金属元素，具有基体效应小、测量范围宽等优点。检出限为0．2－4．0μg/L，回收率为91．5％－103．9％，相对标准偏差为0．29％－1．5％，测定密码样与实际样品，结果令人满意。     

火焰原子吸收光谱法测定固体废弃物磷石膏中微量铜和铅

利用浓硝酸和浓盐酸消解磷石膏固体样品，选择了这两种酸的最佳用最，建立一种磷石膏样品处理方法。研究了应用火焰原子吸收光谱法直接吸取含盐量高的样品溶液，测定其中CU和pb的可行性。一份样品进行7次测定，结果表明，CU和Pb的RSD分别为2．6％和2．0％，加标回收率分别为92.88％一105．04％和91．20％－103．60％。     

共价氢化物与汞离子反应的研究：Ⅳ.痕量砷高灵敏度的分析方法

本文提出了一个氢化物发生－冷原子荧光法间接测定痕量砷的新方法。考察各种实验条件，并将此法用于水及饮料中痕量砷的分析，结果令人满意，对水中痕量砷检出限为０．５μｇ／Ｌ，回收率９４．７－１０３％。     

环丙沙星在胶束体系中的荧光特性研究及应用

研究了环丙沙星在胶束体系中的荧光性质，发现十二烷基硫基酸对环丙沙星有较强的增敏作用。据此建立了胶束增敏荧光光谱法测定痕量环丙沙星的新方法，经样品测定，其线性范围为0．033－0．60μg.mL^-1，检出限为0．033μg.mL^-1，回收率为94．0％－98．1％相对标准偏差为1．5％－2．8％。     

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.