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。     

同一种前处理方法测定烟草中砷、铅和镉

采用同一种前处理方法即硝酸和高氯酸消解处理烟草样品后,氢化物发生-原子荧光光谱法测定烟叶中砷、铅;原子吸收光谱法测定烟叶中镉。样品溶液介质为10%的盐酸,对7个样品平行3次重复实验,其相对标准偏差为砷:0.81%—4.96%、铅:2.82%—5.83%、镉:0.96%—4.60%,砷、铅、镉的检测线性范围分别为:0.0—120.0、0.0—60.Oμg·L^-1和0.0—800.0μg·L^-1,加标回收率:砷在94.5%—96.9%之间、铅在92.7%—101.6%之间、镉在102.2%—110.9%之间。     

硫酸铜中12种微量元素的ICP-AES同时测定

用 ICP- AES法测定硫酸铜中的铅、镉、铝等 12种微量元素 ,钇作内标校正大量铜基体的干扰。加标回收率 93.5 %— 10 5 % ;相对标准偏差 0 .4 1%— 3.6 1%。方法简便、快速、准确 ,检出限可满足日常分析的需要     

卫生纸中铅、镉含量的测定

用原子吸收光谱法对卫生纸中污染元素铅、镉进行了测定。铅在 0 0 0～ 10 0 0 μg·mL- 1 (r =0 9989) ;镉在 0 0 0～ 4 0 0 μg·mL- 1 (r=0 9997)范围内均具有良好的线性关系。本文法的RSD≤ 3 0 8% ,回收率在 94 8%～ 10 4 5 %。方法快速简便 ,结果准确。可用于卫生纸中铅、镉含量的监测     

原子吸收法测定三七中的铜、镉和锂

干法灰化、硝酸浸取盐分 ,原子吸收法同时测定三七中的铜、镉、锂。优化了仪器工作条件 ,对盐酸、高氯酸、硫酸、共存元素干扰进行了试验。该法对铜、镉、锂的检出限分别为 0 .0 0 2 3μg/ m L、0 .0 0 2 6μg/ m L和0 .0 0 2 0 μg/ m L;测定精密度分别为 2 .5 0 %、10 .0 8%和 9.0 2 % ;回收率分别在 96 %— 10 3%、92 %— 10 8%和 96 %— 10 4 %之间。     

固相萃取富集-火焰原子吸收分光光度法测定水中的镉

强阴离子交换固相萃取柱萃取富集 ,火焰原子吸收分光光度法测定环境水样中镉 ,方法相对标准偏差在 2 .5 %— 3.5 %之间 ,加标回收率在 97%— 1 0 4 %之间 ,结果令人满意     

极谱分析法连续测定痕量铅和镉

研究了 Pb2 + 和 Cd2 + 与 KCl-酒石酸钠 -三乙醇胺 -明胶体系的二次导数极谱波。在 p H=4 .5的 HAc-Na Ac介质中 ,Pb2 + 和 Cd2 + 分别于 - 0 .4 6 V和 - 0 .6 4V电位处产生一良好的极谱波。峰电流与 Pb2 + 和Cd2 + 的浓度分别在 1× 10 -5— 3× 10 -1g· L-1和 5× 10 -5— 6× 10 -3 g· L-1范围内呈线性关系。 Pb2 + 和Cd2 +的检出限分别为 1× 10 -7g·L-1和 5× 10 -7g·L-1。本法准确、简便、快速、选择性高。已直接用于饮料中铅和镉的连续测定 ,同时也对酒及面粉样品进行了测定 ,回收率分别为 99.9%— 10 0 .1%和 97.0 %—10 4 .8%。     

微波消解-石墨炉原子吸收法测定中药中铅、镉含量的研究

研究了各因素对样品消解效果的影响 ,优化了石墨炉原子吸收条件 ,建立了一种快速、有效的中药中铅、镉含量的检测方法 ,方法对铅、镉的检出限分别为 0 .14 5 ng/ m L、0 .0 119ng/ m L和线性范围分别为 0—2 0 ng/ m L、0— 2 ng/ m L。样品测定回收率为 96 .7%— 10 3.6 % ,结果满意。     

进口复合肥中重金属铅、镉、铬的测定

本文报道了复合肥中铅、镉、铬的检测方法。采用微波消解为前处理手段 ,石墨炉原子吸收法测定铅、镉、铬 ,并对基体改进剂及用量等一些条件进行了优化选择。复合肥中铅、镉、铬的检出限分别为 6 .9×10 - 1 1 g、4 .5× 10 - 1 2 g、4 .6× 10 - 1 1 g;回收率为 94 %— 10 8%。     

微波消解-石墨炉原子吸收光谱法测定蔬菜中铅和镉

铅、镉是自然界分布很广的两种有害元素。本文利用微波消解-石墨炉原子吸收光谱法测定蔬菜中的铅、镉。方法简便、快捷,铅的回收率在94.5%—101.5%之间,镉的回收率在92.0%—97.5%之间。     

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.     

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.     

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.     

Multi-pulse operation of a Kerr-lens mode-locked femtosecond laser

Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.     

Propagation of Helmholtz-Gauss beams in weak turbulent atmosphere

Based on the Rytov approximation of light propagation in weak turbulent atmosphere,the closed-form expressions of field and average irradiance of each one of the four fundamental families of Helmholtz-Gauss (HzG)beams:cosine-Gauss beams,stationary Mathieu-Gauss beams,stationary parabolic-Gauss beams,and Bessel-Gauss beams,which are propagating in weak turbulent atmosphere,are obtained.The results show that the field and average irradiance can be written as the product of four factors:complex amplitude depending on the z-coordinate only,a Ganssian beam.a factor of complex phase perturbation induced by atmospheric turbulence,and a complex scaled version of the transverse shape of the non-diffracting beam.The effect of weak atmospheric turbulence on irradiance distribution of the HzG beam can be ignored.     

An effective method for reducing speckle noise in digital holography

An effective method for reducing the speckle noise in digital holography is proposed in this paper.Different from the methods based on classical filtering technique,it utilizes the multiple holograms which are generated by rotating the illuminating light continuously.The intensity images reconstructed by a series of holograms generated by rotating the illuminating light possess different speckle patterns.Hence by properly averaging the reconstructed intensity fields,the speckle noises can be reduced greatly.Experimental results show that the proposed method is simple and effective to reduce speckle noise in digital holography.     

Influence of purity of HfO2 on reflectance of ultraviolet multilayer

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry(SIMS) equipment respectively.It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films.In addition,the difference of Zr content in the two kinds of HfO2 single laver films was much laxger than that of the other impurities such as Ti and Fe.which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2.With these two kinds of HfO2 and the same kind of SiO2.we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm.Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively,which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.     

Speech enhancement by array crosstalk resistant ANC and spectrum subtraction

Microphone array-based speech enhancement has great importance for speech communications and speech recognition. To reduce the aperture of the microphone array and to increase the effect of the speech enhancement will greatly broaden the application areas of the microphone array. An array crosstalk resistant adaptive noise cancellation method is therefore presented. And then an improved spectral subtraction algorithm is further cascaded to obtain better enhancement results. Theoretic analysis and experiments indicate that the proposed scheme needs only a very small microphone array while it simultaneously achieves a higher SNR improvement. Besides, the proposed scheme can be used in many noisy environments and is easy for real-time implementation.