离子交换富集-ICP-OES测定沉积物中痕量钼

建立了以717型强碱性阴离子树脂富集-电感耦合等离子体-发射光谱法测定沉积物样品中痕量钼的分析方法,优化了各项仪器条件、化学条件及操作参数。并考察了共存离子的干扰。本法测定钼的检出限为0.09μg/L,回收率在98.2%—105.9%之间,方法应用于沉积物样品中微量钼的测定,获得满意的结果。     

富氧空气-乙炔火焰原子吸收光谱法测定矿泉水中痕量钡

本文研究了用富氧空气 乙炔火焰原子吸收光谱法测定钡 ,比较了乙炔流量、氧气流量及氧炔比的影响 ,当混合空气中含氧量为 5 2 % ,氧炔比为 0 72时对钡有较高的灵敏度。在此火焰中 ,不同浓度的各种酸及大多数金属离子对钡的测定干扰较少 ,当溶液中引入 10 0 0mg·L- 1 K时 ,具有最大的增感及消除干扰的效应。方法的检出限为 0 0 34mg·L- 1 ,灵敏度为 0 16mg·L- 1 / 1% ,相对标准偏差为 2 5 %。     

富氧空气-乙炔火焰原子吸收光谱法测定地质样品中痕量铍

研究了用富氧空气-乙炔火焰原子吸收光谱法测定铍的分析方法。当空气流量为6.0 L·min-1,氧气流量为4.2 L·min-1,乙炔流量为7.4 L·min-1时铍有较高的吸光度。在2.5%的8-羟基喹啉介质中,能较好地消除基体干扰且有一定的增感作用。方法的检测限为0.006 μg·mL-1,测定精密度RSD为4.69％,测定地质标准物质中铍的结果与鉴定值吻合。     

钼-锑-抗分光光度法测定水中黄磷的方法

对钼-锑-抗分光光度法测定水中黄磷进行了研究,结果表明,采用甲苯配制黄磷贮备液能使黄磷很好的溶解,再用环己烷稀释配制标准使用溶液,但甲苯在标准使用溶液中所占比例应≤10％.样品分析时比色管在沸水浴中振荡加热直到无色清亮时取出,加入显色剂定容后避免剧烈振荡,显色时间为60min.Fe3＋浓度较高时会干扰测定可通过加入抗坏血酸来消除,As3＋的浓度＜0.05mg/L时不会干扰测定.样品的预处理采用萃取比为25∶1,以350r/min的速度萃取4min,萃取一次即可.优化实验条件后方法的检出限为0.0004mg/L.     

高分辨连续光源原子吸收光谱法测定植物中的硫

硫元素在富燃的乙炔/空气火焰可形成CS双原子分子,在某些特定的波长下,这些CS分子吸收谱线具有原子吸收的轮廓和一定的吸收强度。文章主要研究利用高分辨连续光源原子吸收光谱法,通过测定硫元素在富燃-乙炔/空气火焰条件下形成的CS双原子分子的吸光度值,从而测定植物样品中的硫元素含量。实验对乙炔-空气比例和燃烧器高度等仪器条件进行了优化;实验研究了五种有机溶剂对CS分子吸收产生的影响情况、其他共存元素的光谱干扰和化学干扰以及不同的消解酸种类对测定结果的影响。在优化的条件下,硫在CS 257.961 nm的检出限为14 mg·L-1。通过对植物标准物质中硫含量的测定比对和精密度实验证明, 利用连续光源原子吸收光谱法,在富燃-乙炔/空气焰条件下以CS分子测定植物样品中的硫元素是一种简单、快速、有效的方法。     

水溶液中Cr^3＋的火焰原子吸收光谱法测试条件的优化

为优化火焰原子吸收光谱法测定水溶液中的Cr^3＋的测试条件,分别采用单因素简单比较法、正交实验设计极差分析及正交实验回归方法考察了光谱通带n,空心阴极灯电流I,燃烧器高度h以及乙炔/空气流量比P对于仪器灵敏度的影响。结果表明单因素简单比较法获得的实验条件最优。乙炔/空气流量比P对火焰原子吸收仪器灵敏度影响最大、其次是光谱通带n,燃烧器高度h和灯电流I的影响很小。测定水溶液中的Cr^3＋时仪器灵敏度最佳的实验条件为：乙炔/空气流量比P=0.4;光谱通带n=0.2nm;灯电流I=5mA;燃烧器高度h=5cm。     

火焰原子吸收光谱法测定锑精矿中铅

本文介绍了火焰原子吸收光谱法测定锑精矿中铅。研究了样品制备方法及共存在元素的干扰，用王水－氢溴酸溶解样品，加入酒石酸抑制锑的水解，试液用空气－乙炔火焰原子吸收光谱法测定。相对标准偏差小于１％，此法优点是干扰少、准确度高、快速和简便等。用本法测定锑精矿中铅，获得满意的结果。     

火焰原子吸收光谱法测定锡基焊料中锑

用盐酸 -过氧化氢溶解样品 ,加入酒石酸抑制锑的水解 ,空气 -乙炔火焰原子吸收光谱法测定锡基焊料中锑。并研究了样品制备方法及其共存元素的干扰。本法简便、快速 ,准确度及精密度均令人满意     

在空气-乙炔焰中络合剂对镱的增感效应

本文在空气-乙炔焰中,借加入有机络合剂以提高能形成难离解氧化物的稀土的灵敏度。以镱为例,研究了含键合原子氧或氧、氮的络合剂对镱的增感效应和镱原子在火焰中的分布。Yb灵敏度达0.17μg/ml/1%吸收,选择性显著提高。本法用于合成样品中镱的测定,结果满意。     

超声浸提-No Gas-电感耦合等离子体质谱法测定工作场所空气中铊及其化合物

铊（Thallium,Tl）是一种有毒的金属元素,主要用于半导体、电子设备、农药和灭鼠剂的生产,会对职业人群的身体健康造成潜在的威胁,工作场所空气中铊及其化合物浓度的测定对保证职业人群的健康具有重要意义。虽然工作场所空气中痕量铊的毒性高于其他有毒金属元素,但对其研究却很少。目前工作场所空气中铊及其化合物浓度检测方法主要是原子吸收光谱法（AAS）,但该方法有不足之处。建立了超声浸提-No Gas-电感耦合等离子体质谱（ICP-MS）测定工作场所空气中铊及其化合物（以205Tl计）的新方法。在采样点,按照GBZ 159-2004方法用0.8 μm孔径的微孔滤膜对工作场所空气进行短时间采样。检测过程中,考察了不同超声浸提条件对测定结果的影响,并对质谱干扰及消除进行了分析。最终优化的实验条件为3%硝酸在室温条件下对采集的滤膜样品进行超声浸提10 min,采用No Gas模式对工作场所空气中铊及其化合物（以205Tl计）进行ICP-MS分析。在该实验条件下得出铊及其化合物在0.087～80 ng·mL-1浓度范围内呈现良好的线性关系（Y=0.009 2X-0.001 8,R=0.999 9）;检出限为0.026 ng·mL-1,当采样体积为75 L时,最低检出浓度为0.001 7 μg·m-3,最低定量浓度为0.005 7 μg·m-3。用质控样品（滤膜中铊质量控制样品ZK147和ZK148）验证了本方法的精密度和准确度,结果显示测定值与参考值之间无显著性差异,相对标准偏差（RSD）为0.77%和0.86%。用加标法（3倍于滤膜中铊含量的常见干扰元素）对建立的新方法进行干扰分析,回收率在97.2%～106.7%之间,表明本法抗干扰能力较强。用本法与国标方法《工作场所空气有毒物质测定 第25部分：铊及其化合物》（GBZ/T 300.25-2017）溶剂洗脱-石墨炉原子吸收光谱法相比较,10个实际样品的测定结果基本一致。相对于现行国标方法,该方法具有操作简单、检出限低、线性范围宽和准确度高的优点,能够满足实际工作场所空气中铊及其化合物的准确、快速、痕量及高通量测定需求。该方法有望成为工作场所空气中铊及其化合物测定的新方法,可更高效地为特定职业人群健康监护提供参考和依据。     

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.     

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.     

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.     

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.