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流动注射-蒸气发生原子吸收光谱法测定生物样品中的汞 总被引:1,自引:1,他引:0
在选择了生物样品最佳消化方法、汞蒸气生成及检测最佳条件等的基础上 ,将流动注射 (FI)与蒸汽发生原子吸收光谱法 (VG- AAS)有机地结合起来 ,建立了生物样品中汞含量的测定方法。该法简便、快速、灵敏度高 ,测定的相对标准偏差 (n=6 )为 2 .8%— 3.3% ,试样加标回收率为 97.2 %— 10 1.4 % ,检出限为 0 .0 5μg· L- 1 ,特征浓度为 0 .5 5μg· L- 1 / 1% ,用于生物样品中汞的测定 ,结果令人满意 相似文献
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针对污泥中复杂基质的特点,进行了三种样品湿法消解体系、还原剂、载流等实验条件的研究,确定了HNO3-HClO4湿法消解体系、5%硝酸载流和0.1%硼氢化钠还原剂、以及标准和样品中5%硝酸+0.05%重铬酸钾混合溶液的酸度介质等,用以测试污泥中痕量Hg的实验条件。该方法快速、准确,易操作,检出限为0.06 μg·L-1,连续11次测定4.0 μg·L-1Hg标准溶液相对标准偏差为2.0%,实验建立的氢化物原子荧光(HG-AFS)测定污泥中痕量Hg的测试方法具有较好的应用前景。 相似文献
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原子吸收法测定有机化合物中的磷和硫 总被引:4,自引:1,他引:3
共振线处于远紫外区的磷和硫元素,不能用一般的原子吸收法直接进行测定。我们在Christian和Feldman及El-Shaarawy提出的间接测定正磷酸根、硫酸根的原子吸收法的基础上进行了改进,结合采用W.Schniger氧瓶燃烧方法破坏有机试样,使有机磷和硫化合物分别转化成磷酸根和硫酸根。对若干有机磷和硫测定与容量法结果相符。磷和硫分析绝对误差为±0.3%。当磷和硫共存时不宜直接使用本法。 相似文献
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根据方法CJ/T 221-2005,建立了火焰原子吸收光谱法测定污泥中镍不确定度数学模型,分析了测试过程中不确定度的来源,并对各不确定度分量进行量化,城市污泥中镍的测定结果为37.72士2.08mg/kg,K=2,即测定结果置信水平95%. 相似文献
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氢化物发生-原子荧光光谱法间接测定中草药中的稀土元素 总被引:1,自引:0,他引:1
稀土元素的化学性质十分相似,能与偶氮胂Ⅲ结合生成稳定的配位化合物,该配位化合物在二苯胍的作用下易被萃取到正丁醇中,再利用减压蒸馏法将有机相蒸干后用稀HCl溶解,加高锰酸钾溶液释放出配位化合物中的As后,用原子荧光光谱法测定As从而间接测定稀土元素。本法以硫酸铈为标准溶液对实验的萃取条件、KMnO4用量、蒸馏温度、偶氮胂Ⅲ用量、干扰离子等条件进行了优化,并采用国家标准物质对方法的精密度和准确度进行验证,测定结果与标准值能很好吻合。在最优条件下,方法检出限为0.44 μg·mL-1,线性范围为0.2~25 μg·mL-1。采用低温灰化,HNO3-H2O2消化法处理中草药样品,测定结果满意,相对标准偏差为1.3%~2.5%,加标回收率为94.4%~106.0%。该法该法简便快速,仪器设备简单,准确度高。将稀土元素富集到有机相,使待测元素与基体分离;将有机相蒸干后酸溶解试样,水相进样能避免有机溶剂对泵管的影响。 相似文献
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采用X射线荧光光谱(XRF)方法测定六种粮食:稻谷(大米)、小麦(面粉)、黄豆、小米、高粱和玉米中生命有机碳含量和化学元素组成,建立一种新方法测定它们的蛋白质含量.粮食中生命有机碳平均含量约为44%.黄豆中的蛋白质含量最高(42.74%),小米蛋白质含量28.56%,麦子蛋白质含量27.57%,玉米蛋白质含量24.99... 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Xin Kang 《中国光学快报(英文版)》2008,6(2)
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. 相似文献
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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. 相似文献
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References: 《声学学报:英文版》2008,27(1):85-96
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. 相似文献