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。     

电感耦合等离子体-质谱（ICP-MS）测定矿泉水中7种微量元素

电感耦合等离子体-质谱（ICP-MS）同时快速测定矿泉水中微量的锂、锶、铅、砷、铜、镉、锰,具有快速、简便、灵敏度高等优点,精密度为1.1%—5.7%（RSD,n=5）,回收率为90%—110%。     

石墨炉原子吸收光谱法测定血清中锰

采用硝酸铵为锰的基体改进剂 ,使用自吸背景校正法 ,测定血清中的痕量锰 ,该法的线性范围为0 .1— 4 0μg/ L;检出限为 1.5 3× 10 -11g;回收率达 96.8%— 10 2 .5 %。     

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。     

ICP-AES同时测定食用菌中钙、镁、铁、锰、铜和锌

微波消化、ICP- AES法同时测定食用菌中的钙、镁、铁、锰、铜和锌。 6种元素的加标回收率为90 .5 %— 10 3% ,RSD为 0 .6 4%— 3.6 % (n=10 )。操作方便 ,分析速度快 ,结果准确     

气相色谱法测定荞头中甲胺磷农药残留量

采用微量化学方法和固相萃取技术 ,建立了气相色谱法简单、快速、准确地测定荞头中甲胺磷农药残留量的方法。探讨了净化方法和色谱分离条件 ,方法的检出限为 0 .0 2 mg/kg,回收率为 87.4 %— 10 9% ,相对标准偏差为 0 .5 %— 2 .5 %之间     

电感耦合等离子体-原子发射光谱法测定银中22种微量元素

应用电感耦合等离子体-原子发射光谱法测定银中铝、金、钡、铋、钙、钴、铬、铜、铁、锂、镁、锰、钼、镍、铅、钯、铂、锡、钛、钒、钇及锌22种微量杂质元素。试液浓度为10mg/mL时,测定范围为10—320μg/g,回收率在94.9%—107%之间,相对标准偏差在3.3%—8.7%之间(n=6)。     

原子荧光光谱法测定膨润土中微量砷

建立了一种原子荧光光谱测定膨润土中微量砷的方法。研究了原子荧光光谱法测定膨润土中微量砷的前处理和干扰。样品相对标准偏差为 4 .1% ,回收率在 93.8%— 96 .5 %之间。该方法简便、快捷 ,分析结果令人满意     

Al(OH)3共沉淀-原子吸收光谱法测定固体盐样中的微量锰

以氢氧化铝共沉淀测定固体盐样中的微量锰,用火焰原子吸收光谱法测定.对试剂的加入量、酸度等进行了实验.选择最佳的共沉淀条件.加标回收率为98.03%-102.3%.对样品进行6次测定的相对标准偏差为:2.05%-3.20%.方法已用于固体盐样的分析,结果满意.     

激光诱导击穿光谱结合多元非线性方法定量分析土壤中锰

锰元素是植物所需的微量元素之一。采用激光诱导击穿光谱(laser-induced breakdown spectroscopy,LIBS)技术对土壤中锰元素进行定量分析。以46个土壤样品为研究对象,获取土壤激光诱导击穿光谱数据,选取锰元素403.1 nm的特征谱线为分析线。根据谱线强度与元素浓度建立定标曲线,相关系数仅为0.78,定标结果说明,由于土壤样品成分的复杂性,锰元素浓度受土壤基体效应影响严重,应根据锰元素在土壤中的存在形式,选取相关元素,建立多元非线性回归定量分析方法,消除基体效应,从而提高LIBS测量的准确性。在多元非线性回归方法中分别考虑碳和铁元素对锰元素浓度的影响。与定标曲线相比,在考虑碳和铁元素对锰元素影响时,LIBS预测浓度与参考浓度的相关系数为0.97,相对误差为3.2%～10.3%,测量的准确度得到提高。实验结果表明,将多元非线性回归方法和激光诱导击穿光谱技术结合可以对土壤中微量锰元素进行定量分析。     

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.     

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.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.