木瓜中多糖和微量元素含量分析

苯酚 -硫酸光度法和原子吸收分光光度法分别测定了木瓜中多糖和微量元素的含量。多糖测定的相关系数为 0 .994 3,平均含糖量为 1 0 .4 9%;微量元素测定回收率为 97.1 %— 1 0 5 .9%,RSD为 2 .4 7%—7.6 0 %。本方法简单可靠 ,适用于木瓜及其制品的常规检测。     

化妆品中铅、镉含量的测定

原子吸收光谱法测定了化妆品中的铅和镉 ,铅和镉分别在 0 .5 0— 10 .0 0 μg·m L-1和 0 .2 0— 8.0 0 μg·m L-1范围内有良好的线性关系 ,相关系数分别为 r=0 .9989和 r=0 .9997;标准偏差分别为 RSD≤1.6 7%和 RSD≤ 4 .71% ;标准加入法测定铅和镉的回收率分别为 93.5 %— 10 6 .0 %和 94 .0 %— 10 5 .5 %。方法简单 ,结果准确。     

亚叶酸钙与对硝基酚荷移反应的研究

本文主要研究了在水溶液中亚叶酸钙与对硝基酚发生荷移反应生成稳定的 1∶ 1络合物 ,络合物的最大吸收波长为 4 0 2 .2 nm,表观摩尔吸光系数为 ε=5 .2 5 5× 10 2 L· mol-1· cm-1,线性范围为 5 0—12 0 0 μg/ m L。回收率为 99.5 8%— 10 2 .6 0 % ,相对标准偏差为 1.4 3%。方法简单、快速、准确度高 ,可用于亚叶酸钙制剂含量的测定。     

火焰原子吸收光谱法测定粤东第一温泉中钾、钠、钙、锰和锌

用火焰原子吸收光谱法测定粤东第一温泉源头水中的钾、钠、钙、锰和锌。测定结果为 :钾 2 .5 5 4mg/ L、钠 2 4 2 .0 mg/ L、钙 74 .4 0 mg/ L、锰 1 .0 78mg/ L、锌 0 .96 0 0 mg/ L,RSD1 .2 1 %— 2 .5 6 %,回收率 98.3%— 1 0 1 .1 %。     

抗坏血酸基体改进剂-石墨炉原子吸收法测定尾矿砂中铂

本文以抗坏血酸 (Vc)为基体改进剂 ,建立了石墨炉原子吸收法直接测定尾矿砂中微量铂的方法 ,并对不同基体改进剂的作用机理作了初步探讨。此方法的特征质量为 1 .3× 1 0 -10 g;检出限为 1 .9× 1 0 -12 g;线性范围为 2— 5 0 0 ng· m L-1;样品的加标回收率为 1 0 0 .7%— 1 0 4 .0 %。     

分光光度法测定发酵液中果糖的含量

针对微生物转化发酵液体系的特征 ,用分光光度法测定其中果糖的含量。校准曲线回归方程为 y=2 6 .2 3x 0 .0 0 7,相关系数为 0 .9991 ;1 0倍量葡萄糖和 1 0倍量甘露醇的存在对果糖测定基本无干扰 ;发酵液中果糖测定的加标回收率为 99.1 %— 99.8%。     

分光光度法测定镧汞齐中的镧

以偶氮胂 为显色剂 ,氯乙酸 -氢氧化钠为缓冲溶液 ,用分光光度法直接测定镧汞齐中镧含量。最佳的显色酸度为 p H2 .8— 3.0 ,最佳测定波长为 6 6 0 nm。镧含量在 0— 75 μg/ 2 5 m L范围内吸光度符合比耳定律 ,线性回归方程为 A=- 0 .0 2 4 8+0 .0 132 C,相关系数 r=0 .9992 ,配合物的摩尔吸光系数 ε为 4 .2 8×10 4L· mol-1· cm-1,回收率为 97.3%— 10 3.6 %。本法显色稳定性好 ,灵敏度高 ,操作简便 ,快速     

磷钼杂多酸-结晶紫分光光度法测定高纯氯化铯中微量磷

以 4 -叔丁基 - 2 (α-甲苄基 )苯酚 (t- BAMBP)萃取分离基体铯 ,磷钼杂多酸与结晶紫染料生成离子缔合物 ,在聚乙烯醇存在下 ,在水溶液中显色。在波长 5 45 nm处 ,其摩尔吸光系数可达 2 .0 1× 10 5L· mol-1·cm-1。方法的回收率为 97%— 10 1% ,相对标准偏差为 0 .8%— 2 .7%。     

硫化银体系共振散射光谱研究及分析应用

Triton X- 1 0 0存在下 ,在碱性介质中 ,Ag 与 S2 -形成 Ag2 S微粒 ,Ag 与 S2 -反应体系的共振光散射(RLS)明显增强 ,建立了水中痕量银的测定方法。Ag 浓度在 0 .0 1 1— 6 .0 0 μg/ m L范围内具有良好的线性关系 (r=0 .9992 )。方法检出限 3.5 6 ng/ m L;相对标准偏差 0 .5 3%— 1 .97%;样品加标回收率 92 .82 %—1 0 6 .0 0 %。方法简便 ,测定体系抗干扰的效果好 ,灵敏度高。     

反相高效液相色谱法同时测定动物组织中苯并咪唑类兽药残留量

本文建立了高灵敏度的苯并咪唑的测定方法 ,通过对实验条件的优化 ,采用反相高效液相色谱法同时测定动物组织中的苯亚砜苯咪唑 (oxfendazole)、噻苯咪唑酯 (cambendazole)、丙苯咪唑 (albendazole)及苯硫达唑 (fenbendazole) 4种苯并咪唑类兽药残留量。测定方法的相关系数 r>0 .9999,检出限为0 .0 1mg/ kg,线性范围为 0 .0 5— 10 .0 mg/ L ,精密度为 2 .1%— 7.3% ,回收率为 74 .8%— 90 .2 %     

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.