断续流动-氢化物发生原子荧光光谱法测定硫磺中的微量砷

采用断续流动-无色散氢化物发生原子荧光光谱法测定硫磺样品中的微量砷含量。采用一系列单一变量优化了酸度、还原剂浓度、共存元素以及载流流速对氢化物发生的影响,本方法快速简单、灵敏度高、检出限低。检测线性范围为1．0—100μg/L,检出限为为0．519μg／L,回收率为91．4％-99．2％。     

双道原子荧光光谱法同时测定土壤中的砷和汞

建立了同时测定土壤中砷和汞的原子荧光光谱法。样品的相对标准偏差 As为 3.94 % ,Hg为 5 .0 0 % ,回收率在 90 %— 93%之间 ,对砷、汞的检出限分别为 0 .18μg/L和 0 .0 5 7μg/L。本法操作简便、快速、灵敏度高。     

流动注射氢化物发生-原子吸收光谱法测定钢铁中的砷、锑

研究了流动注射氢化物发生-原子吸收光谱法测定钢铁中砷、锑试验方法,即仪器工作条件、还原剂的选择、酸度、硼氢化钾浓度、共存离子的影响等条件试验。本方法测定的线性范围：砷：0.05-100μg·L^-1,回归方程为：CAs=0.047A-0.003,相关系数r=0.9996,检出限L（D（As））=0.03μg·L^-1,RSD（As）=1.12%;锑：0.05-100μg·L^-1,回归方程为：D（Sb）=0.0094A-0.0003,相关系数r=0.9996,检出限L（D（sb））=0.03μg·L^-1,RSD（Sb）=1.06%。该方法灵敏度高,测定结果准确可靠、操作方便快速,能满足钢铁中测定砷、锑的要求。     

原子荧光光谱法同时测定化妆品中砷和汞

研究了原子荧光光度法同时测定化妆品中的砷和汞，并试验了硼氢化钠浓度、共存离子的影响，优化了仪器条件。方法回收率分别在：As88．7％-101．0％、Hg97．0％-107．2％之间，砷和汞的检出限分别为0．026μg／L和0．020μg／L；线性范围为As0．5—100μg／L、Hg0.5—70μg／L；RSD(n=6)As1．4％、Hg2．5％。方法具有操作简便、快速、灵敏度高等优点，可用于化妆品中As、Hg的测定。     

微波高压消解双道原子荧光法测定蔬菜总砷和汞

用微波高压消解技术处理样品,用原子荧光光谱仪测定蔬菜中总砷汞,具有快速、方法简便、结果准确可靠的优点.方法的回收率为:砷90.1%-106.9%,汞91.0%-104.0%;检出限为:砷0.10μg/L,汞0.008μg/L.     

双道原子荧光光谱法同时测定农产品中的砷和硒

研究了AFS-930型双道原子荧光光度计同时测定农产品中砷和硒的方法.该法快速,简便,准确,砷回收率为91.9%-99.6%,硒回收率为93.5%-103.8%,相对标准偏差(RSD)砷小于2%,硒小于1%,检出限分别为0.035μg/L和0.038μg/L.     

ICP-AES测定地表水中总砷

用ICP—AES测定地表水中总砷，检出限为：2．97μg/L，回收率在95％-105％之间，相对标准偏差为1.13％-2．24％，结果令人满意。     

氢化物-原子荧光光谱法测定金属饰品中的砷和汞

采用氢化物-原子荧光光谱法测定金属饰品中砷和汞.用体积比为3:1的浓硝酸和浓盐酸微波消解样品.结果表明:砷和汞方法的检出限分别为0.079μg/L和0.037μg/L;砷、汞RSD分别为1.89%和4.82%;砷的加标回收率为99.6%,汞的加标回收率为96.0%.该方法快速简便,能满足饰品的日用检验要求.     

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。     

微波消解-氢化物原子荧光光谱法测定油菜籽中的砷和汞

用用微波消解法处理富含油脂的油菜籽样品,氢化物原子荧光光谱法（HG-AFS）测定其中的砷和汞。砷在1—16μg/L范围内,有良好的相关性,相关系数r=0.9992;汞在0.1—1.6μg/L范围内,有良好的相关性,相关系数r=0.9994;砷和汞检出限分别为3.0μg/kg和1.6μg/kg;砷和汞测定的相对标准偏差RSD分别为9.8%、10%。用标准物质桃叶（GBW08501）验证方法准确性,结果令人满意。     

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.     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

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.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.