PAN浊点萃取-火焰原子吸收光谱法测定水样中的痕量钴

提出了浊点萃取-火焰原子吸收光谱法测定痕量钴的新方法。探讨了溶液pH,试剂浓度等实验条件对浊点萃取及测定灵敏度的影响。在最佳条件下,富集50mL样品溶液,用火焰原子吸收光谱法测定,钴的检出限为0.22μg/L,钴的富集倍率为68倍。方法用于自来水、井水及海水中痕量钴的测定。     

浊点萃取-石墨炉原子吸收光谱法测定环境水样中痕量镉的研究

提出了1-(2-噻唑偶氮)-2-萘酚(TAN)浊点萃取石墨炉原子吸收光谱法测定痕量镉的新方法。详细探讨了溶液pH,试剂浓度等实验条件对浊点萃取及测定灵敏度的影响。在最佳条件下,富集10mL样品溶液,用石墨炉原子吸收光谱法测定,镉的检出限为0.037μg/L,镉的富集倍率为20倍。该方法用于环境水样中痕量镉的测定,获得满意结果。     

浊点萃取-火焰原子吸收光谱法测定微量锌

研究了浊点萃取-火焰原子吸收光谱法测定微量锌的新方法.实际样品采用微波消解,利用非离子表面活性剂TritionX-100、络合剂5-Br-PADAP浊点萃取试样中微量锌(Ⅱ).探讨了溶液pH、试剂浓度等实验条件对浊点萃取及测定灵敏度的影响.在最佳条件下,富集10.0mL的Zn2 溶液,用火焰原子吸收光谱法测定,锌的检出限为4.4ng/mL(3o),富集倍数为10倍,RSD为1.21[C=0.20(μg/mL,n=5)],线性范围为0.15-1.00μg/mL.该方法用于中药及黄豆试样中锌含量的测定,结果令人满意.     

浊点萃取-火焰原子吸收光谱法测定痕量铅的研究

研究了浊点萃取-火焰原子吸收光谱法测定痕量铅的新方法.利用表面活性剂聚乙二醇辛基苯基醚(Triton X-100)和配合剂1-苯基-3-甲基-4-苯甲酰吡喹啉酮-5(PMBP)对试样中的Pb(Ⅱ)进行浊点萃取.并详细探讨了溶液pH值、试剂浓度等实验条件对浊点萃取及测定灵敏度的影响.在最佳条件下,铅的富集倍数为20,检出...     

浊点萃取-分光光度法测定彩笔中的灿烂绿

建立了浊点萃取-分光光度法测定灿烂绿的方法.以非离子型表面活性剂Triton X-114为萃取剂,富集、分离灿烂绿,采用分光光度法进行检测.研究了缓冲溶液用量、表面活性剂用量、平衡温度和平衡时间对浊点萃取的影响,得到最佳实验条件：5％的Triton X-114溶液2.5mL、pH3.8的盐酸-柠檬酸钠缓冲溶液2.0mL、平衡温度和时间分别为50℃和15min.在优化的实验条件下,灿烂绿被萃取到Triton X-114相与水相分离.该方法用于彩笔中灿烂绿的测定,结果满意.     

浊点萃取-火焰原子吸收光谱法测定微量铜

本文研究了浊点萃取 -火焰原子吸收光谱法测定微量铜。利用表面活性剂浊点特性实现胶束相分离 /富集微量待测离子。探讨了影响浊点萃取的因素。该方法用于自来水、河水及标准土壤中痕量铜的测定 ,具有低毒、高效、安全、简便等特点。     

双硫腙浊点萃取-石墨炉原子吸收光谱法测定环境水样中痕量铅的研究

基于表面活性剂的浊点现象,建立了以双硫腙为螯合剂、Triton X-114为表面活性剂的浊点萃取-石墨炉原子吸收光谱法测定痕量铅的新方法。研究了溶液pH值、试剂浓度、平衡温度和加热时间等实验条件对浊点萃取及测定灵敏度的影响。以4 000 r·min-1离心15 min使分相, 分相后的溶液在冰水浴中冷却至接近0 ℃,然后反转离心管弃去水相,用0.1 mol·L-1 HNO₃-甲醇溶液定容至0.5 mL, 溶液以磷酸二氢铵及硝酸镁为基体改进剂由石墨炉原子吸收分光光度法进行测定。在pH 8.0和0.05% Triton X-114及20 μmol·L-1双硫腙存在下, 富集10 mL样品溶液,铅的检出限为0.089 μg·L-1,富集倍率为19.1,所得工作曲线回归方程为A=0.0261c(μg·L-1)+0.010 6,线性范围0.1～30 μg·L-1,相关系数r为0.998。方法用于环境水样中测定痕量铅的测定,获得满意结果。     

浊点萃取-石墨炉原子吸收光谱法测定药物胶囊中的痕量铬（Ⅵ）

采用硝基苯胲铵盐（铜铁试剂）、吡咯烷基二硫代甲酸铵（APDC）为络合剂,Triton X-114为表面活性剂的浊点萃取体系分别富集药物胶囊中的痕量Cr（Ⅲ）和总铬,富集后的Cr（Ⅲ）和总铬用石墨炉原子吸收光谱法进行测定.讨论了溶液pH值、表面活性剂浓度、络合剂浓度、平衡温度、平衡时间等对浊点萃取效率的影响.在优化的实验条件下,铬（Ⅵ）的检出限为0.031μg/L,相对标准偏差为1.2％（C=2.0μg/L,n=6）,加标回收率为98.4％-102.1％.应用该法测定药物胶囊中的痕量Cr（Ⅵ）,结果令人满意.     

浊点萃取-GFAAS测定水中铬的形态

在Triton X-114溶液中,当加热至其浊点温度时,溶液分为两相,Cr(Ⅵ)-DDTC络合物进入非离子表面活性剂相,从而实现与Cr(Ⅲ)的分离,利用石墨炉原子吸收光谱法测定了水中不同形态的铬.方法详细探讨了溶液pH、试剂浓度等实验条件对浊点萃取及测定灵敏度的影响.在最优实验条件下,Cr(Ⅵ)的检出限为0.081μg/L;相对标准偏差为2.57%(C=1.0μg/L,n=6).本方法具有简便、安全、低毒、高效等优点.     

Mn-CCA-CPC浊点萃取火焰原子吸收法测定水环境中锰

使用浊点萃取的方法分离富集水环境中痕量的锰离子,创新性地使用钙羧酸(CCA)与阳离子表面活性剂氯代十六烷基吡啶(CPC)为络合剂与锰离子形成更稳定的三元络合物,以TritonX-114为萃取剂浊点萃取分离富集水环境中的痕量锰,同时采用火焰原子吸收法进行测定,建立了测定水环境中痕量锰的新方法。对影响浊点萃取的主要因素如pH、TritonX-114的用量、CCA用量、CPC用量、NaCl用量、共存离子影响、加热温度、加热时间、离心时间、冰浴时间进行了优化。在优化的实验条件下,Mn2+-CCA-CPC体系分离富集锰有很好地效果,能够很好的克服基体干扰,浊点萃取体系在锰含量0.3～1.5 mg·L-1时呈现良好的线性关系。方法的灵敏度为1.939 mg·L-1,精密度为0.39%,检出限为(3σ)0.27 μg·L-1。测定自来水与井水中的锰含量的结果为33.5和64.5 μg·L-1,同时做加标回收实验,回收率在99.1%～101.5%之间。符合国际标准,因此该方法能够成功应用到水环境中的锰含量的测定,结果令人满意。     

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.     

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.     

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.     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

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.     

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.     

Characterization of PolyA and PolyC mismatches by Raman spectroscopy

A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.