AB5型储氢合金及混合稀土的ICP—AES分析

对于制备镍氢电池负极材料的AB5型储氢合金，制备储氢合金的原材料混合稀土主体元素和杂质元素的分析方法进行了较为详尽的研究。利用仪器的功能软件初步选出各分析元素的多条谱线，通过综合考察各干扰元素对分析元素波长的干扰系数，确定出各元素的最佳分析波长，部分受干扰的元素用干扰系数校正法进行了校正。本法应用于实际产品分析，分析精密度为0．12％1．32％，回收率在94％－106％之间。     

富稀土元素合金中镧,铈,镨,钕,钐测定方法的研究

本文用美国Jarrell-Ash 9000型多道光量计,采用无基体匹配法对富稀土元素合金中镧、铈、镨、钕、钐进行了测定分析。对稀土元素较复杂的光谱干扰运用元素间干扰系数和自身干扰系数校正法进行校正。对其非光谱干扰采取加入内参比进行补偿。通过人工合成样分析和实际富稀土元素合金样品加标准回收实验,表明干扰系数内参比法是一种有前途的无基体匹配的定量分析法。     

ICP-AES中光谱干扰校正的计算方法

本文提出了ICP-AES中多元素共存且相互干扰时,对光谱干扰进行计算的校正方法。以三元系统为例,用下列联立方程式表达各元素间的相互影响, 其中X,Y,Z表示各元素实际含量,X′,Y′,Z′表示对应的实验值,A_b,A_c,B_a…等为干扰系数(A_b表示A对B的干扰系数,余类推)。利用高斯消去法求解,可得其中D=1+A_bB_cC_a+A_cB_aC_b-B_cC_b-A_bB_a-A_cC_a(3)将实验数据代入(2)及(3)式,可求出各元素的含量。一般情况下,干扰系数小于0.1,故若忽略其高次项,则得下式: 选取Ce(418.660nm),Pr(414.311nm),Nd(386.337nm)光谱线为分析线,对他们的五种不同配比的混合物进行实验及计算,用以校验上述公式。所得结果是可靠的。含量为1—5%时,相对误差在4%以内,含量10%—30%时,相对误差在2%以内,含量为～80%时,相对误差在1%以内。当分析物浓度在1%以上时,用(4)式计算的结果与用(2)式所得者基本一致。     

电感耦合等离子体-原子发射光谱法测定红景天中锌、铁、锰和钛

用电感耦合等离子体-原子发射光谱法测定红景天中锌、铁、锰和钛等元素。使用与分析样品基体相接近的标准样品和控制一致的测定条件,克服了物理干扰和基体效应的影响,选择波长为233.0,273.9,257.6,334.9nm4条谱线分别作为测定锌、铁、锰和钛的分析线,测得4种元素的检出限(3s)为0.004—0.05μg/mL。本法测定红景天中4种金属元素的含量,相对标准偏差(n=7)在2.2%—4.2%之间,加标回收率在96.4%—115.2%之间。     

ICP-AES同时测定镍锰钴硅铁铌硼合金中钴、铌、铁和硼

用全谱直读ICP-AES分析技术,对试样溶解方法、元素分析谱线、共存元素干扰、背景校正、仪器分析参数等进行了研究,综合确定了最佳实验条件。将镍锰钴硅铁铌硼合金试样用硝酸、氢氟酸溶解,ICP-AES直接测定钴、铌、铁、硼。测定范围为：Co0.5%—12%、Fe0.1%—3%、Nb0.1%—5%、B0.05%—1.0%。加标回收率为96.6%—103.7%,相对标准偏差为0.37%—4.56%。方法简便、快速、准确。     

聚氨酯人造革中Pb和Cd的ICP-AES测定

ICP- AES法测定聚氨脂人造革中 Pb、Cd两元素 ,研究了干扰情况 ,确定了各元素的检出限 ,方法回收率在 97%— 110 %之间 ,RSD均小于 5 .0 % ,该法用于样品测定 ,结果令人满意     

ICP-AES测定钛基复合材料中镍、钕和铁的研究

采用ICP－AES法对钛基复合材料中的合金元素镍、钕、铁的测定进行了研究，着重进行了基体元素及待测元素镍、钕、铁之间干扰试验及各元素在测定浓度范围内的线性相关性试验，进行了酸度试验，测定了钛基复合材料中3种元素的含量，得到了较好的精密度和准确度。方法简便、可靠，获得满意的分析结果。     

金属掺杂钨基合金阴极的二次电子发射系数研究

实验中制备了W-Re,W-Sc,W-Zr,W-Y合金阴极,其中Re,Sc,Zr,Y元素所占合金阴极材料的质量分数都为5%。二次电子发射系数测试结果显示,Re掺杂合金阴极对提高纯钨阴极二次电子发射能力显著,掺杂5%Re的W-Re合金阴极材料具有最大二次电子发射系数,其值为1.8,相比于纯钨阴极,能够提高80%。鉴于Re对提高纯钨阴极二次电子发射能力显著,对Re掺杂质量分数分别为20%,10%,6%,5%,4%,3%W-Re合金阴极材料二次电子发射系数进行了研究,发现随着Re在W-Re合金阴极材料中含量的降低,其二次电子发射系数在不断增大,仅当Re含量下降至5%左右时,合金阴极具有最大二次电子发射系数,继续下降至4%,合金阴极二次电子发射系数不但没有升高,相反下降至1.41,当下降至3%时,合金阴极二次电子发射系数值迅速降低为1.1。     

开放式微波消化-ICP-MS法快速测定食品中多种微量元素

开放式微波消解系统消化食品样品 ,以 45Sc、89Y、1 1 5In、2 0 9Bi作内标元素抑制分析信号的动态漂移 ,加入 1 %异丙醇消除 C元素对 As、Se等元素的干扰 ,建立食品中多种元素同时测定的ICP- MS方法。对 4类食品 (奶粉、鹅肝酱、水果片、燕麦片 )中的 1 2种元素 (Al、Cr、Ni、Ge、As、Se、Ag、Cd、Sn、Sb、Pb、Hg)进行了直接测定 ,绝大部分回收率在 85 %— 1 1 0 %之间 ;线性相关系数均大于 0 .999;精密度 (RSD)值 <1 0 %。对国家标准物质 (SRM)进行了分析 ,测得值与标准参考值相吻合。该法灵敏度、精密度和准确度都能满足有关标准的要求 ,具有多元素同时分析、样品前处理简单、干扰少、测定快速准确 ,省事省力等优点。     

离子交换-电感耦合等离子体质谱法测定锆锡合金中痕量杂质元素

锆锡合金具有优异的核性能,被广泛应用于核工业领域,其中的杂质元素含量通常控制在很低水平。电感耦合等离子体质谱(ICP-MS)是一种可进行多元素同时分析的无机质谱技术,已普遍应用于冶金分析领域。ICP-MS具有图谱简单、灵敏度高等优点,但也不可避免地存在质谱干扰问题,需要用其他辅助手段予以解决。ICP-MS测定锆锡合金中Cd含量时其所有同位素均被Zr和Sn的多原子离子或同质异位素干扰,需要进行基体分离。建立了ICP-MS测定锆锡合金中Cd, Al, B, Mg等11种痕量杂质元素含量的方法,其中Cd, Mg等6种元素经微型阳离子交换柱分离富集后测定,同时采用干扰校正方程校正了~(113)In对~(113)Cd的潜在干扰;其他杂质元素离子不经分离直接采用内标法测定。在稀氢氟酸介质中, Cd~(2+)等杂质离子被吸附在阳离子交换柱上,而Zr则形成络阴离子不被吸附,杂质元素与基体元素Zr分离并获得富集。杂质离子以盐酸洗脱后用ICP-MS检测,消除了测定Cd时Zr基体对其产生的干扰。主要研究了Cd元素与Zr基体的分离条件,包括上柱酸度、淋洗酸度、洗脱酸度、进样浓度和流速,同时考察了其他杂质元素在经优化实验获得的分离条件下的行为。结果表明, Mg, Mn, Co, Cu, Pb 5种元素具有与Cd类似的分离富集行为,可以同时进行测定。最终获得的分离条件为:流速2 mL·min~(-1),泵入2 mL浓度为50 mg·mL~(-1)的样品(上柱酸度为0.5%氢氟酸),用0.5%氢氟酸淋洗9 min,用10%盐酸洗脱4.5 min后测定。方法的分离周期约为15 min,各元素的检出限介于0.005 8～0.21μg·g~(-1)之间,回收率在85%～110%之间, RSD值小于5%。采用本方法测定了Zr-zirlo核级锆锡合金样品中11种杂质元素的含量,结果的精密度和准确度均满足相应产品标准的要求。     

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.