IR STUDIES ON MECHANISM OF DIRECT OXIDATION OF METHANE TO SYNTHESIS GAS OVER A Ni/Al2O3 CATALYS

The mechanism of the CH4/O2 to syngas reaction has been investigated by FT-IR over a 2.9%(wt)Ni/Al2O3. IR spectra of adsorption of CH4 indicate that chemisorbed O atoms can react selectively with active carbon species (arising from CH4 decomposition) to give CO. IR spectra of adsorption of CH4/O2(2:1 mole ratio) mixture show that CO2 and H2O are the detectable products with no CO, revealing that the reforming of remaining CH4 would not take place. We propose that CO and H2 are primary products in this reaction.     

Rapid and preparative separation of traditional Chinese medicine Evodia rutaecarpa employing elution-extrusion and back-extrusion counter-current chromatography: Comparative study

Traditional Chinese medicines (TCMs) have attracted much attention in recent years. Elution-extrusion and/or back-extrusion counter-current chromatography (EECCC/BECCC) both take full advantage of the liquid nature of the stationary phase. They effectively extend the solute hydrophobicity window that can be studied and rendered the CCC technique particularly suitable for rapid analysis of complex samples. In this paper, a popular traditional Chinese medicine, Evodia rutaecarpa, was used as the target complex mixture for extrusion CCC separations. With a carefully selected biphasic liquid system (n-hexane/ethyl acetate/methanol/water, 3/2/3/2, v/v) and optimized conditions (V_CM = V_C, mobile phase flow rate: 3 mL/min in descending mode, sample loading: 100 mg), five fractions could be obtained in only 100 min on a 140-mL capacity CCC instrument using both elution- and back-extrusion methods. Each fraction was analyzed and identified compared with the data of major standards using LC/MS. Moreover, the performance of both extrusion protocols was systematically compared and summarized. EECCC could be operated continuously and was found extremely suitable for high-throughput separation; however, post-column addition of a clarifying reagent is recommended to smooth the UV-signal during the extrusion process. Considering BECCC, the practical operation is very simple by just switching a 4-port valve to change the flow direction. The change of flowing direction should be done after a sufficient amount of mobile phase has flushed the column in the classical mode so that solutes with small and medium distribution constants have been eluted. Otherwise, a significant portion of the solutes will stay in the mobile phase inside the column, mix together and produce a broad peak showing in the mobile phase eluting after the stationary phase extrusion. Compared with classical CCC or other preparative separation tools, extrusion CCC approaches exhibit distinguished superiority in the modernization process of traditional Chinese medicines.     

ICP—OES同时测定三元复合肥中六种微量元素

用微波消解／电感耦合等离子体发射光谱法（ICP—OES）同时测定了三元复合肥中的铜、铁、锌、镍、锰、钼6种微量元素。结果表明,该法具有简便、快速、结果可靠、检出限低、良好的精密度、精确度、高回收率以及能够同时测量多种元素的优点;通过对比实验测量得到了有效态微量元素的浓度和微量元素的总量,结果显示大部分微量元素是以有效态形式存在于复合肥中。因此,该法可以作测量复合肥类产品中的微量元素的一种参考使用方法。     

Application of ionic liquids based microwave-assisted extraction of three alkaloids N-nornuciferine, O-nornuciferine, and nuciferine from lotus leaf

The application of ionic liquids based microwave-assisted extraction (ILMAE) was successfully developed for extracting three alkaloids N-nornuciferine, O-nornuciferine, and nuciferine from lotus leaf. Seven kinds of 1-alkyl-3-methylimidazolium with different cations and anions were investigated in this work and 1.0 M 1-hexyl-3-methylimidazolium bromide ([C₆MIM]Br) solution was selected as solvent. In addition, the microwave parameters including irradiation power, extraction time and solid-liquid ratio were optimized. Compared with the regular MAE and conventional heat-reflux extraction (HRE), the proposed approach exhibited higher efficiency (0.9-43.7% enhanced) and shorter extraction time (from 2 h to 2 min), which indicated ILMAE was an efficient, rapid and simple sample preparation technique. Moreover, the proposed method was validated by the linearity, reproducibility, and recovery experiments. Good linearity was observed with the regression coefficients (r²) between 0.9998 and 0.9999. The recoveries of all methods were in the range of 94.6% and 105.5% with RSD lower than 6.6%, which indicated that the proposed method was credible.     

Local and parallel finite element method for solving the biharmonic eigenvalue problem of plate vibration

In this paper, we establish a new local and parallel finite element discrete scheme based on the shifted‐inverse power method for solving the biharmonic eigenvalue problem of plate vibration. We prove the local error estimation of finite element solution for the biharmonic equation/eigenvalue problem and prove the error estimation of approximate solution obtained by the local and parallel scheme. When the diameters of three grids satisfy H⁴ = ?(w²) = ?(h), the approximate solutions obtained by our schemes can achieve the asymptotically optimal accuracy. The numerical experiments show that the computational schemes proposed in this paper are effective to solve the biharmonic eigenvalue problem of plate vibration.     

基于正三角形平面模板的摄像机标定与重建

提出一种采用正三角形平面模板标定摄像机内参数并进行重建的方法。模板包含一个正三角形和其重心至3个顶点的连线。用摄像机拍摄3幅以上不同位姿的模板图像,并提取每幅图像上角点的亚像素级坐标,然后计算消失点并拟合消失线,再由两组正交直线的消失点求得圆环点的图像坐标,最后线性求解出摄像机内参数。给出了两种弱化条件的模板,并介绍了恢复欧氏尺寸和摄像机部分外参数的方法。该方法降低了对标定模板的要求,模拟实验和真实实验的结果证明了其具有较高的标定精度。