排序方式: 共有39条查询结果,搜索用时 15 毫秒
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Partially coherent non-paraxial vectorial Hermite-Gaussian beams and their far-field properities 总被引:1,自引:0,他引:1
Aihua Kuang 《Optik》2010,121(19):1799-1801
The far-field theory of partially coherent vectorial non-paraxial beams is expanded and their analytical propagation expressions of the Wigner distribution function matrices and the cross-spectral-density matrices in free space are derived using the far-field approximation. Some interesting cases, in particular the vectorial non-paraxial partially coherent Hermite-Gaussian (HG) beams, are discussed and treated as special cases of our general expressions. It is shown that the fσ and f parameters play an important role in determining vector and non-paraxiality of partially coherent HG beams. When two parameters are small enough, scalar and paraxial vectorial approximation is allowed; otherwise, non-paraxial vectorial approximation is applied. But the decided parameters additionally affect their far-field divergence angles. 相似文献
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石墨炉AAS中气体直接进样技术的研究——氢化物法测定As、Sb、Bi、Sn、Ge和Pb 总被引:1,自引:0,他引:1
本文提出将气体样品经石墨炉的载气入口由载气直接引入石墨炉的技术,实现了石墨炉原子吸收光谱中气体样品的直接进样测定,并成功地应用于氢化物气体的分析,测定了砷、锑、铋、锡、锗和铅,其灵敏度为2.0×10~(-9)g~8.1×10~(-10)g;检出限为2.1×10~(-9)g~6.0×10~(-11)g;线性范围上限为30μg/1~400μg/1;精密度(R.S.D)为0.76%~2.4%。 相似文献
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Analytical methods for inorganic arsenic in water: a review 总被引:2,自引:0,他引:2
Inorganic arsenic, a term which encompasses both As (III) and As (V) species, constitutes the highest toxicological risk associated with arsenic in water in contrast to the organic arsenic species. Different determination methods of inorganic arsenic have been developed over 40 years providing timely and efficient risk assessments of inorganic arsenic contamination world wide. The current report gives an overview of more than 100 papers, regarding existing methods for analysis of As (III) and As (V) in water, including various spectroscopic, ICP and electrochemical techniques. Recent field portable analytical applications are also reviewed. 相似文献
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Mariana A. Vieira Patricia Grinberg Cláudio R.R. Bobeda Mariela N.M. Reyes Reinaldo C. Campos 《Spectrochimica Acta Part B: Atomic Spectroscopy》2009
In recent years, knowledge of the different chemical forms of the elements has gained increasing importance. There has been significant progress in methods that hyphenate chromatographic separations with atomic spectrometry. These hyphenated methods can provide the most complete information on the species distribution and even structure. However, they can be lengthy, relatively costly and difficult to bring to the routine. On the other hand, it is important to remember that chromatographic techniques represent only a minor part of the separation procedures available and, in certain cases, the application of basic chemistry to sample treatments can give quantitative information about specific chemical forms. In this sense, non-chromatographic procedures can provide methods that offer sufficient information on the elemental speciation for a series of situations. Moreover, these non-chromatographic strategies can be less time consuming, more cost effective and available, and present competitive limits of detection. Thus, non-chromatographic speciation analysis continues to be a promising research area and has been applied to the development of several methodologies that facilitate this type of analytical approach. In view of their importance, the present work overviews and discusses different non-chromatographic methods as alternatives for the speciation analysis of clinical, environmental and food samples using atomic spectrometry for detection. 相似文献
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氢化物发生—原子荧光法测定磷矿石中的砷和汞 总被引:13,自引:2,他引:11
研究了氢化物发生原子荧光法测定出口磷矿石中的砷和汞。试验了硼氢化钾浓度,共存离子的影响;优化了仪器条件。方法的回收率为94%-102%,砷和汞的检出限分别为0.5ng/mL和0.05ng/mL。方法具有操作简便、快速、灵敏度高等优点,可用于出口磷矿石中微量As、Hg的测定。 相似文献
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"自动回流消化仪"消化-AFS法测定油中的砷 总被引:2,自引:0,他引:2
本文报道了“自动回流消化仪”消化,原子荧光光度法测定的油中的砷。“自动回流消化仪”消化油既防止了砷元素的损失,又能使油容易消化,同时在试剂用量、劳动强度、消化速度等方面都有较好的效果。原子荧光光度法,采用新的仪器和原理,提出了方法的灵敏度。该法回收率为91.8%-104.7%,相对标准偏差0.51%,与传统湿法消化法比较无显著性差异(t0.05)。 相似文献
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The concept of partially coherent nonparaxial Hermite-Gaussian (HG) beams is proposed. By using the generalized Rayleigh-Sommerfeld diffraction integral, the closed-form propagation equations of partially coherent nonparaxial HG beams in free space are derived. The on-axis intensity, far-field and paraxial expressions, and specifically, the free-space propagation equations of partially coherent nonparaxial Gaussian Schell-model beams are given, and treated as special cases of our results. It is found that the f and fσ parameters play a crucial role in determining the nonparaxiality of partially coherent TEMmn-mode HG beams. Only if the f and fσ parameters are small enough, the paraxial approximation is applicable. 相似文献