催化光度法测定饲料中的痕量锰

在 p H为 9.6 0的条件下 ,锰 ( )催化双氧水氧化酸性铬蓝 K反应 ,建立了测定痕量锰的新催化光度法。线性范围为 0— 15 0 ng/2 5 m L,检出限为 0 .989ng/m L。方法的回收率在 97.0 %— 10 5 .5 %范围内。用于饲料的测定 ,结果令人满意。     

催化动力学光度法测定粮食中微量锰

在醋酸和醋酸钠介质中微量锰对高碘酸钾氧化亚甲蓝褪色反应具有明显的催化作用。据此建立了一种新的催化动力学测定微量锰的方法。方法线性范围为0.2-8.0μg·L^-1,检出限为0.082μg·L^-1。对4.0μg·L^-1锰（Ⅱ）测定的相对标准偏差为1.8%（n=5）。应用于大米等3种粮食中微量锰的测定,平均收率均大于96%。结果令人满意。     

二安替比林对碘苯基甲烷光度法测定烟草样品中锰的研究及应用

研究了新试剂二安替比林对碘苯基甲烷 ( DAp IM)与锰的显色反应 ,在碱性介质中 ,空气氧化 Mn( )为 Mn( )后 ,在磷酸介质中 ,Mn( )氧化 DAp IM生成橙色产物 ,采用分光光度法测定 ,λmax=480 nm,ε=1 .1 8× 1 0 5L· mol- 1· cm- 1。锰含量在 0— 8μg/2 5 m L内符合比耳定律。本法用于烟草样品中锰的测定 ,结果令人满意。     

计算导数分光光度法的研究——Ⅱ.铜、锌、锰的同时测定

本文以5-Br-PADAP-OP为显色体系,用计算导数分光光度法同时测定了铜、锌、锰三组分;比较了不同计算方法,测量波长点的数目及测量波长点在同阶或异阶导数光谱中选取时对计算结果的影响。本方法用于铸铝标样中铜、锌、锰的同时测定,获得较满意的分析结果。     

催化动力学光度法测定痕量锰的研究

基于pH=5.0的醋酸－醋酸钠缓冲体系中，以氨三乙酸为活化剂时，锰（Ⅱ）对溴酸钾氧化2－（5－溴－2－吡啶偶氮）－5－二乙氨基酚的褪色反应具有显著的催化作用，建立了测定痕量锰（Ⅱ）的新型动力学光度法，检出限为8.7×10^-13g/mL，测定范围为0－10nm/25mL。用于人发及天然水中痕量锰（Ⅱ）的测定，结果满意。     

五磷酸铈、锰晶体的发光

本文用蒸发溶液法生长了一系列CeP5O14:Mn晶体,测定了它们的组成和结构.测定了晶体的吸收光谱,激发光谱和发射光谱,观察到Ce3+→Mn2+之间的能量转移和在此体系中锰离子在545nm附近和665nm附近两个波段同时进行发射,并随着锰含量的增加,665nm的荧光强度下降而545nm的强度增加.     

双波长双指示剂催化分光光度法测定水和茶叶中的痕量锰

研究在pH 5.6的HAc-NaAc缓冲溶液中,氨三乙酸活化痕量锰离子催化高碘酸钾氧化灿烂绿和萘酚绿B的指示反应,通过测定460nm和630nm下催化体系与非催化体系吸光度值的变化,建立了双波长双指示剂催化分光光度法测定痕量锰的新方法。在最佳实验条件下,测定痕量锰离子的线性范围为0.010—0.60μg/25mL。检出限为1.2×10-10g/mL。此法用于水和茶叶中痕量锰的测定,结果满意。     

石墨炉原子吸收光谱法测定人血清中微量锰

采用石墨炉原子吸收光谱法测定人血清中微量锰 ,回收率为 10 5 .0 % ,检出限为 7.7× 10 -10 g/ m L,相对标准偏差为 6 .5 16 %。本方法简单、快速和准确 ,已用于血中微量锰的测定 ,结果令人满意。     

锰(Ⅱ)-高碘酸钾-孔雀绿测定水中痕量锰

在 p H为 4 .0的 HAc- Na Ac缓冲溶液中 ,Mn( )对 KIO4 氧化孔雀绿具有催化作用 ,据此理论 ,本文以氨三乙酸为活化剂 ,氟化钠为掩蔽剂 ,用抗坏血酸中止反应 ,建立了一种间接测定锰的动力学光度法 ,其检出限和测定范围分别为 3.8× 10 -11g/ m L和 0 .5 ng/ m L— 2μg/ m L。该法已用于水中微量元素锰的测定 ,结果令人满意。     

CTMAB增敏催化动力学光度法测定痕量锰

研究了以NTA为活化剂,CTMAB增敏, Mn(Ⅱ)催化KIO₄-氧化7-(2-硝基-4-甲基苯偶氮)-8-羟基喹啉-5-磺酸 (简称7P8Q5S)的反应,建立了催化光度法测定痕量锰的新方法,以509 nm为测定波长,Mn(Ⅱ)在0～3.2×10-9 g·mL-1的范围内成线性关系, 检出限为3.8×10-11 g·mL-1,考察了20多种共存离子的影响,用于测定大米、绿豆、小米和土壤中的锰。     

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.