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。     

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.     

微波消解-氢化物发生原子荧光法测定重油中的砷和汞

采用微波消解处理样品,以硫脲为预还原剂硼氢化钾为还原剂,氢化物发生原子荧光法测定重油中的砷和汞。采用微波消解方法进行样品处理,其结果表明,方法具有高效快速、试剂消耗量少、节能、环保等优点。考察了预还原剂硫脲和抗坏血酸对测定结果的影响。考察了酸度、还原剂浓度、基体效应、光电倍增管负高压、原子化器高度、灯电流和载气流量的影响,优化操作条件。测定砷和汞的线性范围分别为2~12μg/L和0.2~1.2μg/L,线性回归方程为If=a*c+b(c:μg/L),相关系数分别为0.9998和0.9981,砷和汞的检出限分别为0.009μg/L和0.007μg/L,对7个样品进行回收实验,砷、汞的回收率分别为90%~109%、92%~105%准确度较高;11次测定的标准偏差小于5%,精密度较好。本方法用于重油中砷和汞分析,可满足科研和生产需要。     

氢化物发生-原子荧光光谱法测定淡水鱼中砷和汞

应用AFS820双道原子荧光光度计同时测定鱼肉、鱼骨中的砷和汞含量,样品采用湿消解法和干灰化法。结果表明,砷和汞在鱼骨中富集量高于鱼肉。该方法对砷、汞的检出限均小于0.06μg/L,RSD（n=5）：砷〈4.8%、汞〈6.2%,回收率分别为90%—118%和92%—115%。     

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。     

微波消解-氢化物发生原子荧光光谱法测定土壤中砷和硒

采用王水(1 1)作消解剂,以微波消解的方法处理土壤样品,氢化物发生-原子荧光光谱法测定土壤中砷、硒,设定了最佳的样品处理条件和仪器测定条件.利用加标回收试验,对分析方法进行了验证.砷、硒的检出限分别为0.94μg/L和0.15μg/L,测定土壤中砷、硒的回收率分别为90%-105%、89%-104%,RSD分别为2.2%-4.0%、1.9%-3.1%.     

原子荧光光谱法测定环境水中砷、硒和汞

原子荧光光谱法测定环境水中砷、硒和汞,试验了标准系列的配制方法;硼氢化钾浓度、盐酸酸度对测定的影响;优化了仪器条件。砷、硒和汞检出限分别为0.51μg/L、0.53μg/L、0.065μg/L,相对标准偏差(n=11)分别为1.51%、2.36%、1.63%,加标回收率分别为90.0%-105.0%、92.0%-97%、90.0%-97.5%。     

基体溶液改进-原子荧光法测定食品中的汞

探讨改进基体溶液双道原子荧光光谱法测定食品样品中的汞。样品消解后用6mol/L盐酸、硫脲+抗坏血酸(50g/L)作为基体溶液进行仪器测定。本方法检出限0.051μg/g,最低检出质量浓度0.10μg/L,相对标准偏差为7.45%、6.76%,回收率为88.6%—113.2%。方法具稳定性好、灵敏度高、检出限低等优点。     

同一种前处理方法测定烟草中砷、铅和镉

采用同一种前处理方法即硝酸和高氯酸消解处理烟草样品后,氢化物发生-原子荧光光谱法测定烟叶中砷、铅;原子吸收光谱法测定烟叶中镉。样品溶液介质为10%的盐酸,对7个样品平行3次重复实验,其相对标准偏差为砷:0.81%—4.96%、铅:2.82%—5.83%、镉:0.96%—4.60%,砷、铅、镉的检测线性范围分别为:0.0—120.0、0.0—60.Oμg·L^-1和0.0—800.0μg·L^-1,加标回收率:砷在94.5%—96.9%之间、铅在92.7%—101.6%之间、镉在102.2%—110.9%之间。     

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.     

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.     

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.     

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.     

Research on beamforming method for dual-line array with space mismatch between the two line arrays

The performance of port/starboard discrimination of dual-line array will be seriously degraded when the space between the two line arrays of the dual-line array is mismatched. The directivity function of the delay-sum and delay-subtract beamforming is deduced and the port/starboard discrimination of the delay-sum and delay-subtract beamforming is also studied both under the ideal status and the status under which the space between the two line arrays of the dual-line array is mismatched. Analysis results show the delay-subtract beamforming has better performance of port/starboard discrimination. At last, the sea trial results demonstrate the theoretical results.     

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.     

Retrieval of ultraviolet skylight radiances and O3 slant column densities from balloon-borne limb spectrometer

With a novel light-weight and absolutely calibrated ultraviolet （UV） spectrometer, UV skylight radiances and O3 slant column densities are measured by balloon-borne limb measurements in Xinjiang area, China. UV skylight radiances measured at the height of 31 km are compared with the results from Modtran in the wavelength range from 290 to 420 nm. O3 slant column densities are derived from radiance spectra in the Huggins bands （320 - 335 nm） using differential optical absorption spectroscopy method. And the parameter exhibits a good correlation with the same value simulated by radiative transfer model （Tracy）. The O3 profile simultaneously measured by an O3 sonde is used as input in Tracy calculations. The O3 sonde is launched on the same balloon.