荧光法直接测定环境水中痕量苯酚

研究了荧光分光光度通过控制酸度直接测定环境水中苯酚的新方法。在pH＝1时，直接测定苯酚的含量，波长为λex／λem＝270／297nm，检出限为4．0g/mL，线性范围为0－3．2μg/mL。回收率为99％－101％。     

铋磷钼蓝分光光度法测定金属硅中磷

本文建立了测定金属硅中磷的方法，检出限为0．0020％，回收率为92％－104％。     

一阶导数分光光度法测定汽油中共轭二烯烃

本文应用共轭双烯在酸性介质中，可以使磷钼酸铵还原成磷钼蓝的反应，建立了测定汽油中共轭双烯烃含量的一阶导数分光光度法。该方法的相对标准偏差≤4．1％，加标回收率为96．2％－105．0％，与气相色谱法进行对照实验，两方法测定结果相吻合。     

ICP—AES法测定复合肥中磷,钾,锌,锰和硼

用ＩＣＰ－ＡＥＳ法同时测定了复合肥中磷，钾锌锰和硼，确定了仪器的工作参数，对分析线的选择，背景扣除。酸度影响和共存元素间的干扰等进行了研究。方法的回收率为９５％－１０４％，相对标准偏差为２．６６％－５．５４％。     

微波消解、流动注射-氢化物发生原子荧光光谱法测定三七中硒含量

用微波消解、流动注射－氢化物发生原子荧光光谱法测定三七中硒，通过实验选择最优化的测定条件，方法的检出限为0．30μg.L^-1，相对标准偏差为1．2％，线性范围为0－100μg.L^-1，相关系数为0．9999，回收率为96．7％－100．7％。     

萃取-磷钼蓝比色法测定镍铬丝中磷

在0．7—1．0mol/L的硝酸介质中^[3]，采用萃取-磷钼蓝比色法测定镍铬丝中的磷，络合物的最大吸收峰位于680nm，测定范围为0．001％-0．05％，相对标准偏差为＜3．8％。     

ICP-AES测定饮用水源中的Cu、Mn、Pb、Cd、Zn

用ICP－AES法同时测定饮用水源中的Cu、Mn、Pb、Cd、Zn等重金属元素，具有基体效应小、测量范围宽等优点。检出限为0．2－4．0μg/L，回收率为91．5％－103．9％，相对标准偏差为0．29％－1．5％，测定密码样与实际样品，结果令人满意。     

火焰原子吸收光谱法测定固体废弃物磷石膏中微量铜和铅

利用浓硝酸和浓盐酸消解磷石膏固体样品，选择了这两种酸的最佳用最，建立一种磷石膏样品处理方法。研究了应用火焰原子吸收光谱法直接吸取含盐量高的样品溶液，测定其中CU和pb的可行性。一份样品进行7次测定，结果表明，CU和Pb的RSD分别为2．6％和2．0％，加标回收率分别为92.88％一105．04％和91．20％－103．60％。     

ICP－AES法同时测定磷铁中的主含量元素和杂质

本文研究用ＩＣＰ－ＡＥＳ法同时测定磷铁的主含量元素Ｐ和杂质元素Ｓｉ、Ｍｎ、Ｔｉ、Ｖ、Ｃｒ的方法。采用碱熔酸化分解试样，选Ｂ为测Ｐ的内标元素，回收率为９６％－１０２％，最大相对标准偏差为８．６０％，大多数结果的相对标准偏差小于５％。     

火焰原子吸收光谱法测定铜镍矿浮选产品中铜、镍、镁

研究了用火焰原子吸收光谱法在同一溶液体系中直接快速测定金川铜镍矿浮选产品中铜、镍、镁含量新的新方法。考察了产品中高含量的SiO2对测定镁的干扰情况，并提出了排除这项干扰简便方法，根据各元素的标准溶液系列的测定数据，推算出了铜、镍、镁3元素的线性回归方程及线性相关系数，特征浓度铜为0．40mg.L^-1/1%，镍为0．48mg.L^-1／1％，Mg为0．018mg.L^-1／1％；线性浓度范围铜，镍均为0－10mg.L^-1，镁为0．2－1．2mg.L^-1。相对标准偏差铜为2．5％(n=6)，镍为2．3％（n＝6），镁为2．8％（n=6），加标回收率铜为96．5％－102．5％，镍为98．8％－103．5％，镁为98．2％－102．5％，这种方法操作简便，快速，实用，具有较好的精密度和准确度，实际产品分析结果与外检单位及金川公司测定的结果吻合。     

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.