聚丙烯酸钠增敏抑制高碘酸钠氧化夜蓝褪色光度法测定痕量锡

建立了聚丙烯酸钠增敏抑制高碘酸钠氧化夜蓝褪色光度法测定痕量锡的新方法。该方法基于聚丙烯酸钠增敏锡 ( )抑制高碘酸钠氧化夜蓝褪色反应 ,在最佳条件下 ,锡 ( )的含量在 0 .2 0— 2 .0 μg/L范围内与 ΔA值呈线性关系 ,其校准曲线的回归方程 ΔA=0 .0 0 788+ 0 .10 9CSn( ) (μg/L) ,r=0 .9992 ,检出限(L D) =1.1× 10 -11g/m L。本方法用于测定人发样品和水样中的锡含量 ,其相应的回收率为 10 0 .3%和10 0 .0 %。相对标准偏差为 3.4 %和 3.2 %。     

2′,7′-二氯荧光素荧光光谱法测定饲料中微量总砷

在 p H=7.5缓冲溶液中 ,I2 与 2′,7′-二氯荧光素反应 ,引起荧光猝灭 ,加入 As3 与 I2 反应 ,体系荧光增强 ,基此建立了荧光光谱法间接测定微量As3 的新方法。荧光发射波长为 λem=5 2 0 nm。砷含量在 1 0— 1 0 0 .0 μg/L范围内呈现良好的线性关系 ,回归方程为 ΔIF=0 .4 92 0 0 .70 0 5 C(C:μg/L) ,相关系数 r=0 .9980 ;检出限为 1 .0 μg/L。本法用于饲料样品中微量总砷的测定 ,获得满意的结果。     

流动注射在线共沉淀HG-AFS测定地质样品中痕量锡

建立了流动注射在线共沉淀HG AFS测定痕量锡的分析方法。方法基于锡在碱性介质中与氢氧化镁共沉淀 ,沉淀收集在锥形沉淀腔中 ,用HCl溶洗沉淀和NaBH4反应 ,产生的氢化物被载气引入原子化器中进行测定。测定锡的相对标准偏差为 5 15 % ( 3 0ng·mL-1,n =10 ) ,检出限为 0 2 1ng·g-1,检出限较直接进样降低了 12倍。对国家标准参考物中锡的测定结果与标准值相符。     

高效液相色谱法测定杀虫剂灭幼脲三号的含量

本文采用 Hypersil- ODS2 ( 4 .6mm× 2 50 mm,5μm)柱 ,乙腈 -水 - N,N-二甲基甲酰胺 ( 60∶ 4 0∶ 0 .1)为流动相 ,测定波长为 2 54nm,建立了测定灭幼脲三号的高效液相色谱法。该法线性范围为 2 .0— 80μg/m L,回归方程为 A=52 .4 1C+0 .1936,相关系数 r=0 .9987,精密度为 3.5% ( n=11,C=4 0μg/m L) ,检出限为 0 .0 5μg/m L。平均回收率在 96%— 10 4 %之间 ,已用于 2 5%水剂样品的测定 ,结果令人满意。     

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     

反相高效液相色谱法测定1-(4-硝基苯)-3-(5-溴-2-吡啶)-三氮烯

ZORBAX Eclipse XDB- C8(4.6× 1 5 0 mm,5 μm)色谱柱 ,乙腈流动相 ,流速 0 .6 0 m L/min,检测波长4 2 0 nm,反相高效液相色谱法测定 1 - (4-硝基苯 ) - 3- (5 -溴 - 2 -吡啶 ) -三氮烯。该法的线性范围为 1—1 0 .0 μg/m L,线性回归方程为 A=5 .91 5 4 .4 37C,相关系数 0 .9989,相对标准偏差为 0 .8973%(C=7.2 0 μg/m L,n=5 ) ,检出限为 0 .0 2 872 μg/m L,平均回收率在 93.2 %— 1 0 2 .2 %之间。     

动力学分光光度法测定食品中微量碘

在硫代硫酸钠存在下的硫酸介质中 ,碘对溴酸钾氧化间胺黄褪色具有抑制作用 ,建立了测定微量碘的新方法。测定线性范围为 0 .0 2— 0 .4 mg/ L ,检出限为 1 .5× 1 0 -8g/ m L。用于食品中微量碘的测定 ,结果令人满意     

高效液相色谱法测定金盏菊中叶黄素

KNAUER Eurospher- 1 0 0 C1 8(3.9mm× 30 0 mm,4 .6 μm)色谱柱 ,以乙腈 -甲醇 -乙酸乙酯混合液为流动相 ,流速 1 .0 m L/ min;检测波长 4 6 0 nm;柱温 2 5℃ ,高效液相色谱法测定金盏菊中叶黄素含量。校准曲线法定量 ,检出限为 3.0 mg/ m L。叶黄素含量在 8— 6 4mg/ L之间线性关系良好 ,r=0 .9999,RSD=1 .4 % ,回收率在 97%— 1 0 1 %之间。本法适合叶黄素产品中叶黄素含量的测定     

催化动力学光度法测定乙醛催化剂中的微量钯

基于 p H 5 .5 0的乙酸 -乙酸钠介质中 Pd( )催化次磷酸钠还原结晶紫的褪色反应 ,建立了测定微量钯的催化动力学光度法 ,研究了最佳反应条件和动力学参数。方法的检出限为 4 .7× 1 0 -9g Pd( ) /m L,线性范围为 0— 0 .8μg/2 5 m L,表观摩尔吸光系数为 7.6× 1 0 5L· mol-1· cm-1,用于测定乙醛催化剂中的微量钯 ,取得满意结果     

碘蓝分光光度法测定微量铬（Ⅳ）

基于在酸性介质中 ,重铬酸钾与碘化钾、淀粉的显色反应 ,建立了碘蓝分光光度法测定微量铬 ( )的方法。铬 ( )浓度在 0— 0 .6μg/ m L范围内有良好的线性关系 ,方法的相对标准偏差为 1.3% ,表观摩尔吸光系数为 5 .6 3× 10 4 L· mol- 1 · cm- 1 ,检出限为 2 .0× 10 - 3μg/ m L     

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.