钇基体改进剂石墨炉原子吸收法测定微量锗

本文利用硝酸钇做基体改进剂，石墨炉子原子吸收法测定植物样品及土壤样品中的微量锗，本方法采用涂钼热解石墨管，有效地避免了测定过程中锗的损失，方法的检出限为５．９×１０＾－１２ｇ，对于３０μｇ／Ｌ，锗的相对标准偏差为４．０％。     

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％。     

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。     

草酸铵作稳定剂石墨原子吸收法直接测量土壤悬浮液中微量镉

本研究了石墨炉原子吸收法直接测量土壤浮液中微量镉。比较子不同基体改进剂及背景吸收对测量的影响。并以草酸铵为稳定剂对悬液的稳定性进行了研究，结果表明在碱性条件下，使用０．００７ｍｏｌ·Ｌ＾－１的草酸铵作稳定剂时，土壤悬浮液比较稳定。应用固体悬浮液进样方法，直接测定了土壤样品中的微量镉。     

流动注射在线萃取－火焰原子吸收光谱法测定明胶中的微量Fe和Cu

本文采用氧化水解制样及流动注射在线萃取火焰原子吸收光谱法，测定明胶中微量Ｆｅ和Ｃｕ，解决了水解法制样测定结果偏低和不能直接测定低含量样品的问题。本方法测定Ｆｅ和Ｃｕ的灵敏度分别提高了１４．５倍和１７．６倍，分析速度达３６次／ｈ，Ｆｅ和Ｃｕ的回收率分别在９０．８－１１０．５％和８７．５～１０７．０％之间，测定精密度分别为４．５３％和４．２６％。     

固体进样石墨炉原子吸收光谱测定研究（Ⅱ）：镉的测定

采用自制的石墨炉微量固体进样装置，结合Ｌ＇ｖｏｖ平台、基体改进以及预热时通入空气等技术，直接测定了部分植物、粮食、土壤与沉积物中的痕量镉。初步解决了上述试样测定中的基体干扰、背景扣除疑难问题。标样测定取得了满意的结果。变异系数６．２～１１．０％；回收率９３～１０５％。     

萘相萃取双波长分光光度法测定微量铜的研究

本文用蔡作萃取剂，以５－Ｂｒ－ＰＡＤＡＰ为显色剂，采用双波长分光光度法测定微量铜的研究。研究表明，选择５４０－３８３ｎｍ，为测定波长时，络合物最大吸收峰为５４０ｎｍ，表观摩尔吸光系数为１．２６×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，铜量在０－５．０μｇ／７ｍＬ范围内符合比耳定律，方法应用于食品，水样品铜的测定，结果满意。     

草酸铵作稳定剂石墨炉原子吸收法直接测量土壤悬浮液中微量镉

本文研究了石墨炉原子吸收法直接测量土壤悬浮液中微量镉。比较了不同基体改进剂及背景吸收对测量的影响。并以草酸铵为稳定剂对悬浮液的稳定性进行了研究,结果表明在碱性条件下,使用０．００７ ｍ ｏｌ·Ｌ－ １ 的草酸铵作稳定剂时, 土壤悬浮液比较稳定。应用固体悬浮液进样方法, 直接测定了土壤样品中的微量镉     

等离子体发射光谱法测定单晶硅中微量锗

本文阐述了用等离子体发射光谱法测定单晶硅中微量锗的方法。试验了三种样品制备方法，结果表明，样品溶解于硝酸加氢氟酸中，除云硅后直接测定锗的方法最好，其检出限是0.0237μg/mL，合成样品的回收率为99.9%－100.2%，相对标准偏差小于3.6%。     

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.