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％     

石墨炉原子吸收法测定麦芽粉中的锗和硒

本文叙述了平台石墨炉原子吸收法测定麦芽粉中的锗和硒，采用Ｐｄ＋Ｎｉ和Ｐｄ基体改进剂，使锗和硒的灰化温度分别提高到１４００和１２００℃，有效地消除了基体干扰。方法特征量为３１ｐｇ（Ｇｅ）和２３ｐｇ（Ｓｅ），检出限为２８ｐｇＧｅ和６２ｐｇＳｅ（３σ）。对含２２￣１１０μｇ／ｇＧｅ和１８￣３５μｇ／ｇＳｅ的样品测定，相对标准偏差为Ｇｅ３．７￣５．６％（ｎ＝９），Ｓｅ４．３￣６．５％（ｎ＝９），回收率在９     

石墨炉原子吸收法测定饮料和中成药中锗

本文研究了石墨炉原子吸收（ＧＦＡＡＳ）直接测定某些饮料和中成药中的锗。选用钯和酒石酸为改进剂与纯钯比较，灰化温度提高至１６００℃未见锗的损失，灵敏度提高了３７％。具有较强的抗干扰的能力。本法特征质量ｍｏ值为３２ｐｇ，实际样品测定检出限为０．２４μｇ／Ｌ（３σ计），相对标准偏差为２．６％，回收率８９％－１１０％。     

平台石墨炉原子吸收法测定高温镍基合金中痕量碲

用镍作基体改进剂，碲的灵敏度提高的约２倍，灰化温度提高４００℃，抗干扰能力明显增强，不需要分离样品基体，采用平台石墨炉即可同温镍基金中痕量磅。方法检出限为０．０４１μｇ／ｇ，样品中碲含量为０．５μｇ／ｇ时，相对标准偏差为３－６％，回收率在９０－９９％之间，方法简单快速。     

火焰原子吸收光谱测定微量锗的研究

本文研究了空气－乙炔火焰原子吸收分光光度法测定饮料及灵芝酒中微量金属元素锗。该法线性范围宽（５０－３００μｇ／ｍｌ），选择性强，并有良好的精密度和准确度。样品加标回收率为９７．９－１０３．４％，变异系数１．４％。本方法适用于保健滋补饮品中锗的分析。     

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。     

原子吸收光谱法测定有机锗（Ge—132）中的锗及其杂质

火焰原子吸收法测定有机锗（Ｇｅ－１３２）中的锗，线性浓度范围为０－１．２５ｍｇ／ｍＬ，方法精度为１．２％，相对标准偏差〉２％，平均回收率为９９．５％，杂质Ｐｂ和Ａｓ用塞曼石墨炉原子吸收测定，Ｐｂ用（ＮＨ４）２ＨＰＯ４＋Ｍｇ作改进剂，Ａｓ用Ｐｄ作改进剂，特征质量分别为８．２ｐｇ和８ｐｇ，相对标准偏差分别为２．１％和２．２％，并讨论了有关机理问题。     

微波消解石墨炉原子吸收光谱法测定蒙山全蝎中的痕量锗

建立了石墨炉原子吸收光谱法测定蒙山全蝎中痕量元素锗的方法.通过程序控温、控压的分步微波消解方式消解样品,优化石墨炉升温程序,采用Ni(NO3)2为基体改进剂,以氘灯扣除背景,在265.2nm波长下测定蒙山全蝎中痕量元素锗.在选定分析条件下,锗的检出限为0.30μg/L,RSD的范围为1.2%-3.1%,回收率为88.9...     

平台石墨炉原子吸收法测定茶叶中的微量镉

本文提出了平台石墨炉原子吸收法测定镉的方法，以０．２ｍｇ／ｍＬ，ＰｄＣｌ２＋０．２ｍｇ／ｍＬＭｇ（ＮＯ３）２的混合液作基体改进剂，能有效的消除生物样品的基体效应，方法简单，精密度好，利用标准曲线即可测定茶叶样品中镉。     

原子吸收光谱法测定有机锗（Ge─132）中的锗及其杂质

火焰原子吸收法测定有机锗（Ｇｅ．１３２）①中的锗，线性浓度范围为０－１．２５ｍｇ／ｍＬ，方法精度为１．２％，相对标准偏差＜２％，平均回收率为９９．５％。杂质Ｐｂ和Ａｓ用塞曼石墨炉原子吸收测定，Ｐｂ用（ＮＨ_４）_２ＨＰＯ_４＋Ｍｇ作改进剂，Ａｓ用Ｐｄ作改进剂，特征质量分别为８．２ｐｇ和８ｐｇ，相对标准偏差分别为２．１％和２．２％，并讨论了有关机理问题。     

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.