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221.
Gold in ores was determined by flame atomic absorption spectrometry following on-line preconcentration by sorbent extraction in a flow-injection system. The medium polarity adsorption resin Amberlite XAD-8 packed in a 220-μl micro-column was used to collect gold(III) from hydrochloric acid sample solutions for 40 s at 7.6 ml/min. Ethanol was used to elute the adsorbed analytes into the nebulizer. Optimization studies were made on sample loading rate, elution rate and sample acidity. Some possible interferences on the determination are discussed. A 35-fold enrichment was achieved at a sampling frequency of 60 h?1 and with an RSD of 1.4%. The detection limit (3σ) and 2 μg l?1. Results for gold in ore samples showed good agreement with those obtained using activated carbon adsorption preconcentration. The recoveries were 97–108%. 相似文献
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本文借助文[1]除去零空间的技巧,利用L—S度数理论讨论了一类浙近线性波方程。在对非线性项不做单调性假设的前提下,给出了一个新的多解定理。 相似文献
226.
In this paper, the transformations of generating systems of Euclidean space are examined in connection with the Drazin inverse of their Gram matrices and the notion of biorthogonal systems is generalized. The results obtained in this paper can be considered as the extension of some recent results concerning Moore-Penrose biorthogonal systems and reflexiveg-inverse systems in Euclidean spaces. 相似文献
227.
采用改进分析型嵌入原子法计算了Pt(110)表面自吸附原子的能量和法向力.当Pt吸附原子位于Pt(110)表面第一层原子的二重对称洞位上0.11nm时最稳定.Pt吸附原子的最佳迁移路径是由一个二重对称洞位沿密排方向迁移到最近邻的另一个二重对称洞位.在吸附原子远离表面的过程中,将依次经过排斥、过渡和吸引等三个区域.在排斥区和过渡区,由于吸附原子与表面原子间强的相互作用势,吸附原子的能量和法向力的形貌图均为(110)面原子排列的复形,与对势理论和嵌入原子法得到的结果一致.在吸引区,由于多体相互作用及晶体中原子
关键词:
金属表面
自吸附
能量
力 相似文献
228.
Qingfeng Zhang Shanjia Xu 《International Journal of Infrared and Millimeter Waves》2006,27(11):1539-1552
A novel uniplanar 2-D composite right/left-handed transmission line (CRLH-TL) structure is proposed based on a general transmission
line theory and the way to increase the relative operating bandwidth in the left-handed (LH) region and lower the LH operating
frequency is illustrated. In addition, a new method to extract parameters and calculate the Bloch impedance of the structure
is presented. Numerical results of the dispersion as well as the extracted parameters are given, which are calculated based
on full-wave simulation. The present 2-D uniplanar CRLH-TL structure is applicable to 2-D left-handed materials in lower and
wider LH frequency range.
Supported by the National Natural Science Foundation of China (No. 60371010) (No. 60471037) (No. 63531020) 相似文献
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P. Xu Shining Zhu 《量子光学学报》2006,12(B08):85-85
An intense comb-shaped Raman spectra were obtained from a two-dimensional nonlinear x(2) photonic crystal - a hexagonally poled LiTaO3 crystal with lattice parameter 9 micros. The lowest Raman shift was down to 2 cm^-1 and the order of anti-stokes and stokes signals both achieved 11. The novel Raman spectra were mediated first by intense phonon-polariton fields, which were driven through the quasi-phase-matched coupling between the incident dual-beam both from an optical parametric oscillation laser, and further amplified greatly also by such quasi-phasematched nonlinear optical process. The dependence of the Raman spectra character on the wavelength and intensity of incident beams were studied in detail, which accordingly revealed information of the inelastic scattering and the elementary excitation in the nonlinear medium. These results on the other hand suggest technological importance for developing a novel Raman laser with the multi-wavelength output and a tunable frequency interval and for possible applications in quantum optics. 相似文献