用水解分离-原子吸收光谱法对锰作形态分析

研究了痕量锰形态分析的水解分离-原子吸收光谱法。依据不同价态锰水解酸度的不同,使以各种形态存在的锰彼此分离以对其进行AAS测定。用NaOH溶液调试样的pH到10,此时以MnO-₄形式存在的高价锰不产生水解沉淀,而低价Mn(Ⅱ)和中价Mn(Ⅳ)产生水解沉淀,对清液中的Mn(Ⅶ)进行AAS测定;然后用pH为5的硫酸溶液溶解沉淀,此条件下Mn(Ⅱ)的沉淀溶解, 从而使Mn(Ⅱ)和Mn(Ⅳ)彼此分离,对清液中的Mn(Ⅱ)进行AAS测定;最后,用pH为1的硫酸溶液溶解Mn(Ⅳ),并沉淀进行AAS测定。从上述测定,可分别求得Mn(Ⅱ), Mn(Ⅳ)和Mn(Ⅶ)含量。该方法的加标回收率分别在93.3%～99.5%,96.7%～103%和98.2%～104%之间,相对标准偏差分别为2.7%,3.2%和3.1%,检出限为0.10 mg·L-1,该法简单,快速,准确。     

铬渣中铬,镍,锌,锰和铁的X射线荧光法测定

本文首次研究了用X射线荧光光谱法测定铬渣中Cr、Zn、Ni、Mn和Fe元素的模拟标样,样品直接压片不经化学处理。用稀释样品校正试样的基体效应。用人工模拟标样所建立的元素浓度与X射线强度间的线性函数关系令人满意,所试元素的线性相关系数均在0.99以上,测定结果与化学法基本一致。Cr的检测下限为0.036%;Fe为0.039%;Ni为35.33μg/g;Mn为498.18μg/g;Zn为55.61μg/g。各元素的相对标准偏差均低于2.48%。并首次用非线性方法研究了铬渣样品稀释比中Cr、Ni、Zn、Mn、Fe与X射线强度的线性关系。     

火焰原子吸收光谱法测定废水中的重金属离子

采用火焰原子吸收光谱法测定了废水中的重金属离子,测定结果为:Cu,2.89mg/L;Mn,1.08mg/L;Pb,0.98mg/L;Zn,0.96mg/L;Fe,0.95mg/L;Cr,0.10mg/L;Cd,0.08mg/L。相对标准偏差分别为:2.3%,1.9%,2.0%,1.8%,1.5%,2.3%,1.4%。     

迷迭香中微量元素与黄酮类化合物的含量分析

以甲醇为溶剂用索氏提取法提取迷迭香中总黄酮,用比色法测定了其含量;并采用电感耦合等离子体-原子发射光谱仪(ICP-AES)测定了该植物中9种微量元素的含量.结果表明:迷迭香中黄酮类化合物的含量为1.61mg/g,加样回收率为98.98%-100.06%,RSD为0.419%(n=6),该法操作简便,重现性好,适合于黄酮类化合物含量的测定;迷迭香中Fe、K、Mg、Mn、Zn含量丰富.     

电感耦合等离子体-原子发射光谱法测定新锆合金(锆-锡-铁-铬-铌)中10种微量杂质元素

IPC-AES测定了新锆合金中10种微量杂质元素Al、Co、Cu、Mg、Mn、Mo、Ni、Pb、Ti和V.试液浓度为10mg/mL时,测定范围在20-1060μg/g之间,回收率在94%-108%之间,相对标准偏差(RSD,n=6)为4.3%-7.4%之间.     

FAAS和HG-AFS研究野生葛根中微量元素的溶出特性

采用HNO₃-HCIO₄消解体系,应用火焰原子吸收光谱法（FAAS）和氢化物发生-原子荧光光谱法（HG-AFS）测定了洞口县野生葛根中Zn、Fe、Cu、Mn等15种微量元素的含量,方法对试样中各元素测定的相对标准偏差（RSD）为1.07%—4.29%,加标回收率为90.00%—104.00%,方法快速、准确、灵敏度高,适用于葛根中微量元素含量的测定。同时考察了微波提取、超声提取和传统煎煮法对野生葛根中15种微量元素的溶出情况。结果表明:野生葛根溶出液中含量较多元素的顺序为:Zn>Cu>Mn>Se>Fe,其余元素的含量均很少;野生葛根中Zn、Cu、Mn和Se的水溶性强,其溶出率比Fe高很多。     

ICP-AES测定基体沉淀分离后的硫酸铜中10种微量元素

研究了应用硫氰酸铵与铜离子加热生成硫氰酸亚铜沉淀而分离出铜基体,用ICP-AES同时测定硫酸铜样品中As、Cd、Co、Cr、Fe、Mg、Mn、Ni、Pb、Zn的方法.该方法检出限为0.001-0.11μg/mL,加标回收率为88.6%-100.9%,RSD小于2%.本方法快速简便,应用于硫酸铜的测定,结果令人满意.     

黑龙江膜荚黄芪多糖及微量元素Fe、Zn、Cu和Mn的测定

采用水提醇沉法制备黄芪多糖提取物,苯酚-硫酸分光光度法测定多糖的含量,在0.00-0.14mg/mL线性范围内具有良好的线性关系,回收率在94.81%-103.50%.测定黄芪多糖含量为4.3%.采用校准曲线法,用空气-乙炔火焰原子吸收光谱法测定样品中Fe、Zn、Cu和Mn的含量,膜荚黄芪中微量元素含量较高.     

原子吸收光谱法测定冬凌草中的矿物元素

用原子吸收光谱法测定冬凌草中影响人体健康的8种矿物元素Cu、Zn、Fe、Mn、Ca、Mg、Se和Pb的含量。样品经硝酸-高氯酸消解后,采用偏振塞曼效应扣除背景吸收,用火焰原子吸收光谱法检测积分吸收测定冬凌草中Cu、Zn、Fe、Mn、Ca和Mg的含量,用石墨炉程序升温原子吸收光谱法检测峰值吸收测定Se和Pb含量。测定结果显示:该方法的精密度RSD为1.22%—5.64%;加标回收率为95.0%—110.5%;8种矿物元素的检出限(P=95%,α=0.5)分别为Cu0.034、Zn0.0028、Fe0.031、Mn0.110、Ca0.367、Mg0.132mg·mL-1,Pb1.40μg.L-1和Se1.86μg.L-1。该方法简便快速、灵敏、准确,适用于中药冬凌草中矿物元素含量的测定。     

长白山区野生、种植贝母和白术中微量元素的ICP-MS对比分析

用ICP-MS对长白山区野生、种植的贝母和白术中草药中Cu,Fe,Zn,Mg,Mn,Sr,Cr,Co,Se,Pb和Cd等多种微量元素进行了分析测定。比较了灰化法和微波消解法处理样品对测定结果的影响,研究表明,用HNO₃-H₂O₂作消化液微波消解处理样品,精密度和回收率较好;在选定的实验条件下,各元素间互不干扰,可在同一样品液中进行多种元素的分别测定;贝母和白术含有丰富的Cu,Fe,Zn,Mg和Mn,野生的贝母和白术中Fe含量较种植的高;重金属元素Pb、Cd含量野生较种植的低;野生贝母和白术中都含有Co,而种植的贝母和白术中都未检出Co, RSD≤4.85%（n=7）,加标回收率为 96.8%～103.4%。     

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.