电感耦合离子等离子体-原子发射光谱法测定银中22种微量元素

应用电感耦合等离子体-原子发射光谱法测定银中铝、金、钡、铋、钴、铬、铜、铁、锂、镁、锰、钼、铅、钯、铂、锡、钛、钒、钇及锌22种微量元素.试液浓度为10mg/mL时,测定范围为10-320μg/g,回收率在64.9%-107%之间,相对标准偏差在3.3%-8.7%之间(n=6).     

标准加入法测定锆铀合金中微量铪

应用标准加入ICP-AES测定锆铀合金中微量铪.当试样中锆的浓度为8mg/mL时,铪的测定范围是50-400μg/g,回收率为101%-106%,相对标准偏差(RSD,n=6)为3.7%-5.8%.     

微波消解-氢化物原子荧光光谱法测定食品中的微量元素硒

采用HNO3-HClO4作为消解剂,在微波消解炉中消解样品,原子荧光光谱法测定食品中的微量元素硒.在最佳测定条件下测定元素硒的线性回归方程为:IF=95.4853C 9.2045,线性范围为0.5-10.0μg/L,相关系数r=0.9997.回收率2.0μg/L为95.65%-103.04%,6.0μg/L为95.61%-102.42%;相对标准偏差2.0μg/L为2.18%-3.55%,6.0μg/L为2.22%-3.98%.食品样品采用微波消解后,可用氢化物原子荧光光谱法测定其中的微量元素硒.     

超声提取-气相色谱法测定底质中的邻苯二甲酸酯

样品经风干、研磨、过筛,用10 mL二氯甲烷/丙酮(1 1,V/V)超声提取二次,每次10 rain;过滤后,提取液经氦吹浓缩再用正己烷进行溶剂置换,以乙醚/正己烷(1 4,V/V)为洗脱液用氧化铝柱净化;净化后的提取液用带电子捕获检测器的气相色谱仪检测4种邻苯二甲酸酯(DMP、DEP、DBP和DEHP.在优化的条件下,4种PAEs的检出限均在0.62-1.21(g/kg之间;相对标准偏差在0.05%-9.65%之间;回收率在88%-101%之间.并用此方法对实际样品进行了测定.     

电感耦合等离子体-原子发射光谱法测定不锈钢材料中钴、铜、钒

应用电感耦合等离子体-原子发射光谱法(ICP-AES)对测定不锈钢材料中钴、铜、钒三种元素进行了试验研究.取样量为2.0 mg/mL时,测定范围在125-2000 μg/g之间,相对标准偏差(RSD,n=6)在1.8%-6.7%之间.     

顺序注射氢化物发生-原子荧光光谱法测定海带中无机砷和总砷

研究了样品消解方式及载流酸度、硼氢化钾浓度、载气流量等因素对测定结果的影响.校准曲线在1.0-10μg/L的范围内线性良好,相关系数为0.9998.检出限为0.041μg/L,相对标准偏差为1.73%(n=11),加标回收率为90%-110%.     

溴酸钾-猩红3B体系中催化光度法测定痕量亚硝酸根

基于稀磷酸介质中亚硝酸根催化溴酸钾氧化猩红3B的褪色反应,建立测定痕量亚硝酸根的新方法.方法检出限为1.36×10-3μg/mL,线性范围为0.012-0.080μg/mL,回收率为98.8%-101.0%.方法已用于水中亚硝酸根的测定,结果令人满意.     

微波消解-电感耦合等离子体-质谱测定蔬菜中的铅和镉

用微波消解-电感耦合等离子体-质谱测定蔬菜中的Pb和Cd,方法简便、快速.Pb和Cd检出限分别为0.14μg/L和0.13μg/L,相对标准偏差(RSD,n=5)＜4.69%,标准加入法回收率Pb为96.0%-104.0%,Cd为95.0%-110.0%.方法经国家一级植物标准物质验证,结果与推荐值相符.     

微波消解-氢化物发生原子荧光光谱法测定土壤中砷和硒

采用王水(1 1)作消解剂,以微波消解的方法处理土壤样品,氢化物发生-原子荧光光谱法测定土壤中砷、硒,设定了最佳的样品处理条件和仪器测定条件.利用加标回收试验,对分析方法进行了验证.砷、硒的检出限分别为0.94μg/L和0.15μg/L,测定土壤中砷、硒的回收率分别为90%-105%、89%-104%,RSD分别为2.2%-4.0%、1.9%-3.1%.     

微波消解-火焰原子吸收光谱法测定蒙药乌兰-3中铁和锌

以微波消解系统处理传统蒙药乌兰-3,火焰原子吸收光谱法在选定的仪器工作条件下测定了其中的Fe和Zn.测定Fe和Zn的特征浓度分别为0.18和0.051μg/mL/1%;回收率分别为98.5%-101.3%和98.0%-102.5%;RSD分别为0.40%和1.60%;方法简便、结果令人满意.     

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.