钯－抗坏血酸基体改进剂平台石墨炉原子吸收光谱法测定贻贝标样中的砷

本实验建立了钯－抗坏血酸基体改进剂平台石墨炉原子吸收光谱法测定贻贝中砷的方法。研究了基体改进剂氯化钯、抗坏血酸用量对测定的影响，比较了氯化钯－抗坏血酸、氯化钯、硝酸镍三种基体改进剂及平台石墨管、普通石墨管在测定贻贝中砷的灵敏度。方法的相对标准偏差为３．２％，回收率在９７．８％—１０７．４％之间，检出限为１２．０ｎｇ／ｍＬ。     

铝－氟－DSPCF分光光度法测定地下水中铝

本文研究了铝－氟－１，５－二（２－羟基－５－磺基苯基）－３－氰基甲（ＤＳＰＣＦ）的显色反应。在硼酸－硼砂介质中，显色反应灵敏，最大吸收波长为６１０ｎｍ，配合物的表现摩尔吸光系数５．０×１０４，铝含量在０－１５μｇ／２５ｍＬ符合比尔定律。该法用于地下水中微量铝的测定获得了满意结果。     

泡沫塑料吸附—石墨炉原子吸收光谱法测定地质物料中痕量铊

本文研制定了一种泡沫塑料吸附－石墨炉原子吸收光谱法测定地质物料中痕量铊的分析，在所先定的实验条件下，方法检出限为０．０５μｇ／ｇ、样准曲线范围为１０－３００ｎｇ／ｍＬ，Ｔｌ含量水平为０．７１μｇ／ｇ时的测定精度为６．０％，方法回收率９９．０％－１００．０％。经标样及大量样品分析验证，分析方法准确可靠。     

高温合金中磷的测定－磷锑钼杂多酸－结晶紫－PVA光度法

本文报告在少量硫酸介质存在下，以酒石酸锑钾、钼酸铵与磷酸根形成磷锑钼杂多酸，再以结晶紫为显色剂，用聚乙烯醇水溶液为增敏稳定剂，研究了磷锑钼杂多酸－结晶紫－ＰＶＡ体系在水溶液中直接光度法测定高温合金中的磷含量，实验表明，磷与酒石酸锑钾、钼酸铵、结晶紫在聚乙烯醇存在下，形成稳定的蓝色络合物，在波长６８０ｎｍ处吸收大干扰小。磷含量在０．００２－０．０２ｍｇ／５０ｍＬ符合比尔定律。试样中含锡干扰测定，此方法具有操作简便快速。     

黄嘌呤氧化酶－乙醛－吖啶酯化学发光分析新体系

乙醛在黄嘌呤氧化酶催化作用下，被空气氧化生成乙酸和过氧化氢，酶反应生成的过氧化氢氧化新吖啶酯试剂［１０－甲基－９－（对甲酰苯基）吖啶羧酸酯氟磺酸盐］产生化学发光，化学发光强度与己醛浓度在一定范围内成线性关系．由此建立了一种化学发光分析新体系，用于测定乙醇含量．线性范围２．０×１０－７～１．２×１０－３ｍｏｌ／Ｌ，测定５．０×１０－７ｍｏｌ／Ｌ乙醛，相对标准偏差为６．８％，检测限为１．２×１０－７ｍｏｌ／Ｌ，测定环境水样中乙醇含量，取得满意结果，回收率为９５～１０６％．     

蒙药“草布－25”中微量锗的测定

本文采用分光光度法，以丁基罗丹明Ｂ与锗钼杂多酸形成缔合型的三元配合物测定对肺癌有一定疗效的蒙药“草布－２５”中锗的含量，锗含量在０－７．５μｇ／２５ｍＬ范围内服从比耳定律，回收率在９７％－１０４％。     

钯—抗坏血酸基体改进剂平台石墨炉原子吸收光谱法测定贻贝标样中的砷

本实验建立了钯－抗坏血酸基体改进剂平台石墨炉原子吸收光谱法测定贻贝中砷的方法。研究了基体改进剂氯化钯、抗坏血酸用量对测定的影响，比较了氯化钯－抗坏血酸、氯化钯、硝酸镍三种基体改进剂及平台石墨管、普通石墨管在测定贻贝中砷的灵敏度。方法的相对标准偏差为３．２％，回收率在９７．８％－１０７．４％之间，检出限为１２．０ｎｇ／ｍＬ。     

正三辛胺萃取－5－Br－PADAP－OP显色体系光度法测定铜

采用５－Ｂｒ－ＰＡＤＡＰ－ＯＰ显色体系测定铜，考查了测定条件。以正三辛胺萃取分离干扰高子，考查了萃取分离条中。人工合成样品回收率１００．８％，铝合金标样测定误差＜－２．２％，人发分析结果的相对标准偏差＜４．０％。     

超声雾化空气－氩ICP－AES的检出限

医用超声雾化器改装后作为ＩＣＰ－ＡＥＳ的进样装置。在高频功率３．８×０．８０ｋＷ，载气流量０．８０Ｌ·ｍｉｎ（－１），观察高度１．０ｃｍ的折衷条件下，测定了２７种元素的检出限，１５种稀土元素中Ｄｙ、Ｅｕ、Ｈｏ、Ｙ和Ｙｂ的检出限低于１μｇ·Ｌ（－１）。     

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％     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

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.     

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.     

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.     

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.     

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.