阻抑高碘酸钠氧化依莱铬红B褪色光度法测定痕量Sn(Ⅱ)

在加热和 NH3 - NH4Cl(p H=9.2 5 )缓冲溶液介质中 ,痕量 Sn( )能抑制高碘酸钠氧化依莱铬红 B褪色反应 ,据此建立了测定痕量 Sn( )的动力学光度分析新方法。该方法在锡的浓度为 0 .5— 9.0μg/ 2 5 m L范围内有良好的线性关系 ,方法的检出限为 2 .33× 10 -9g/ m L Sn( )。该方法用于测定天然水中痕量锡( ) ,取得满意结果     

抑制CTMAB催化结晶紫褪色光度法测定痕量铝(Ⅲ)

基于碱性介质中 ,铝 (Ⅲ )对溴化十六烷基三甲铵 (CTMAB)催化结晶紫的褪色反应有明显的抑制作用 ,建立了一种抑制 -催化褪色光度法测定痕量铝 (Ⅲ )的新方法。此法在 0 .0 2— 1.8μg/L的范围内 CAl(Ⅲ )与 ΔA值呈线性关系 ,线性回归方程为 :ΔA=0 .0 0 2 93+ 0 .2 179CAl( Ⅲ ) (μg/L) ,r=0 .9990 ,检出限为 1.4×10 -9g/m L。该法用于水样中 Al(Ⅲ )的测定 ,结果令人满意。     

阻抑高碘酸钠氧化铬天青B褪色光度法测定痕量钛

基于加热和 NH3- NH4 Cl(p H=10 .2 0 )缓冲溶液存在下 ,痕量钛 ( )能阻抑高碘酸钠氧化铬天青 B的褪色反应 ,建立了阻抑高碘酸钠氧化铬天青 B褪色光度法测定痕量钛 ( )的新方法。该方法的线性范围为 0— 4 0 .0 ng/ m L Ti( ) ,检出限为 5 .85× 10 - 1 0 g/ m L ,用于鲍鱼壳中痕量钛的测定 ,结果令人满意     

催化碘酸钾氧化VB4R-DBS离子缔合物褪色光度法测定痕量亚硝酸根

基于加热和 p H=7.5 0的条件下 ,NO-2 催化碘酸钾氧化维多利亚蓝 4 R(VB4 R) -十二烷基苯磺酸钠(DBS)离子缔合物的褪色反应 ,建立了一种测定痕量亚硝酸根的新催化光度法。 NO-2 浓度在 1.0—10 .0 μg/ L范围内服从比耳定律 ,检出限为 1.0× 10 -11g/ m L。该法用于测定水样中的 NO-2 的含量 ,结果令人满意     

中性红褪色光度法测定蒙药铜灰体系中产生的过氧化氢含量

在 p H=3.5的乙酸 -乙酸钠缓冲溶液中 ,用中性红褪色光度法测定了蒙药铜灰体系中产生的过氧化氢的含量。过氧化氢在 0— 5 0μg/ 2 5 m L范围内与 lg(A0 / A)值呈线性关系 ,线性回归方程为 lg(A0 / A) =2 .5× 10 -3+1.0 5× 10 -2 C双氧水 (μg/ 2 5 m L) ,r=0 .9999     

高碘酸钾催化光度法测定痕量铑

在磷酸和热水浴中 ,Rh( )催化高碘酸钾氧化二甲基黄褪色 ,由此建立了测定铑的新催化光度法。本方法的线性范围为 0— 4 .0 μg/ 2 5 m L,检出限为 4 .71× 10 -10 g/ m L。对 2 .0 μg/ 2 5 m L Rh( )测定的相对标准偏差为 1.4 3% (n=11) ,催化反应的表观活化能为 12 5 .8k J/ mol。此法已用于某些催化剂和冶金产品中痕量铑的测定 ,结果令人满意。     

催化动力学光度法测定禽蛋中的痕量硒(Ⅳ)

在酸性介质中及三乙醇胺存在下 ,以硒 ( )对硫化钠氧化亚甲基蓝褪色反应具有很强的催化作用为依据 ,优化了该催化反应的动力学条件 ,建立了利用动力学光度法测定硒 ( )的新方法。在 0— 5 0μg/ 5 0 m L范围内 ,硒的含量与褪色反应 ( A0 - A)呈很好的线性关系 ,检出限为 3.74× 10 -7g/ L。该方法具有良好的选择性和准确度 ,用于禽蛋中痕量硒 ( )的测定 ,结果令人满意     

催化过硫酸钾氧化银-邻二氮菲-荧光黄离子缔合物褪色光度法测定痕量铋(Ⅲ)

基于 p H=5.50弱酸性介质中 ,铋 ( )催化 K2 S2 O8氧化 [Ag(phen) 2 ]+ · [FIn]-离子缔合物的褪色反应 ,建立了一种催化褪色光度法测定痕量铋 ( )的新方法。该方法线性范围为 0 .0 4— 0 .4 mg/ L,检出限为 6 .0× 10 -11g/ m L。用于发样及水样中 Bi( )的测定 ,获得了令人满意的结果 ,并对反应的机理进行了探讨。     

酸性品红褪色光度法测定痕量铁(Ⅲ)

基于Fe(Ⅲ)可使酸性品红氧化褪色,建立了一种褪色光度法测定铁的新方法,该方法线性范围为0-8.25μg/mL,检出限为3.72×10-4μg/mL.用于水样中Fe(Ⅲ)含量的测定,回收率在90%-100%.     

催化动力学光度法测定铝合金中痕量钛

本文研究了在硝酸介质中 ,痕量 Ti( )催化过氧化氢氧化甲基橙褪色的指示反应。优选出催化褪色反应的最佳条件 ,建立了测定痕量钛的新方法。方法的检出限为 4 .8× 10 -11g/ m L,测定范围为 0—0 .88μg/ 2 5m L,用于测定铝合金中的痕量 Ti( ) ,获得了满意的结果     

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.