消化-石油醚提取氢化物-原子荧光光谱法测定食用油中砷

采用消化 -石油醚提取方法处理食用调味油样品 ,以氢化物 -原子荧光光谱法测定砷 ,研究了样品的处理方法、线性关系及检出限 ,建立了快速测定食用调味油中砷含量的原子荧光光谱法。相对标准偏差小于1.79% ,加标回收率 96 .7%— 10 3.8%。     

氢化物发生-原子荧光光谱法测定进口未焙烧黄铁矿中总砷含量的不确定度评定

以氢化物发生-原子荧光光谱法测定进口未焙烧黄铁矿中总砷含量为例,建立了数学模型,对测试过程中的各个分量进行分步计算和合成,计算出扩展不确定度为0.007％,评定结果表明校准曲线是氢化物发生-原子荧光光谱法测定进口未焙烧黄铁矿中总砷含量不确定度的主要影响因素.     

氢化物发生-原子荧光法测定饮料中砷含量的不确定度评定

本文以氢化物发生-原子荧光光谱法测定饮料中砷含量为实例,建立了数学模型,对测试过程中不确定度的各个分量进行了分步计算及合成,计算出扩展不确定度为0.0011mg/L.结果表明校准曲线是氢化物原子荧光法测定饮料中砷含量不确定度的主要影响因素.     

氢化物发生-原子荧光光谱法测定7种中草药中不同形态的水溶性砷

微波提取样品后,使用树脂分离不同形态的砷,以盐酸为测定介质,硫脲-抗坏血酸为预还原剂,硼氢化钾为还原剂,用氢化物发生-原子荧光法测定7种驱虫类中草药中的不同形态砷含量。砷含量在10—100ng/mL浓度范围内线性关系好,回收率在91.4%—106.4%之间。本方法简便、快速、灵敏、准确,可用于中草药中砷的形态测定。     

正丁醇萃取-稀盐酸溶解原子荧光光谱法间接测定中草药中钼

建立了正丁醇萃取稀盐酸溶解原子荧光光谱法间接测定中草药中钼的方法。基于As(Ⅴ)和钼酸铵在浓度为0.3 mol·L-1硫酸介质中能形成砷钼杂多酸,且该杂多酸可以被有机试剂萃取,萃取后蒸干有机试剂,残渣用稀盐酸加以溶解,原子荧光光谱法间接测定钼的含量。在优化的实验条件下,钼的含量在0～15 μg·L-1范围内呈良好的线性关系。方法的检出限是0.44 μg·L-1, 相对标准偏差1.1%。据此对中草药样品进行分析,平均加标回收率介于95.6%～101.3%之间。     

原子荧光光谱法测定土壤中的砷

应用原子荧光光谱法测定砷的含量。以深层生土、地表熟土为样品,采用顺序注射氢化物发生-原子荧光光谱法进行测定。在最佳实验条件下,方法的线性范围在2—60μg/L以内,相关系数r=0.9993,检出限为0.16μg/L,测定标准溶液的RSD为1.6%(n=11),样品加标回收率为96.5%—103.5%,方法简单、快速,可测定土壤中的砷。     

氢化物发生-原子荧光光谱法测定铜阳极泥中的砷

用氢化物发生-原子荧光光谱法测定铜阳极泥中的砷量,研究了仪器测量条件、氢化物发生条件、共存元素等因素对测定结果的影响.选择了最佳测定条件,砷的测定范围为0.50%-5.00%,加标回收率在98.3%-108.0%之间,相对标准偏差小于4%,能满足测定的要求.     

氢化物原子荧光光谱法监测砷中毒患者血液中的砷

对砷中毒患者血液中砷的监测对其临床排砷治疗有重大的指导意义.采用硝酸-高氯酸混酸消解样品,抗坏血酸-硫脲做还原剂,氢化物原子荧光光谱法测定砷中毒患者血液中的砷.运用这种方法能够快速、准确检测出砷含量,从而能够及时监测砷中毒患者血液中的砷,对临床具有重大意义.     

氢化物发生-原子荧光光谱法测定海水中As(Ⅲ)和As(Ⅴ)

提出了一种断续流动注射氢化物发生—原子荧光光谱法测定海水中砷的方法。优化了流动注射氢化物反应发生条件为：5.0％盐酸-0.1 mol·L-1柠檬酸为载流和样品介质,2％ KBH₄-0.5％ KOH还原剂,用氩气将产生的砷化氢带入氢氩焰中原子化,原子荧光光谱法检测。有机砷在此实验条件下不形成干扰,As(Ⅴ)须经预还原后测定。分析了青岛栈桥海滨浴场等海域采集的实际海水样品,实验结果表明海水样品中有机砷含量低,在大批量样品测定时,测定海水中As(Ⅲ)和As(Ⅴ)的量可以近似反映近海海域中砷污染情况。     

微波消解-氢化物发生-原子荧光光谱法测定三氧化二锑中砷

以微波消解分解样品,减少了样品前处理的时间,避免了挥发组分的损失。氢化物发生原子荧光光谱法测定三氧化二锑中砷含量,系统地研究了微波消解、氢化物发生的最佳条件。在此条件下测定砷,得出该方法的检出限为0.35μg/L,相对标准偏差小于5%,加标回收率为91.2%—100.3%。     

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.