Zhao L.-C.,Hebei Geological Laboratory |
Hu Y.-Q.,Hebei Geological Laboratory |
Wang J.-G.,Hebei Geological Laboratory |
Cheng W.-C.,Hebei Geological Laboratory |
And 2 more authors.
Yejin Fenxi/Metallurgical Analysis | Year: 2015
Indium in lead-zinc smelting dust existed in the form of indium sulfide, indium oxide and indium sulfate. The samples were separated with proper reagents. Then, the content of indium in indium sulfide, indium oxide and indium sulfate was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Compared to the classical extraction-atomic absorption spectrometry (AAS), polarography and colorimetric method, the proposed method was rapider and more accurate. The selective solvent for each phase, the dosage of solvent, the dissolution condition of sample, the analytical line of elements, the parameters of instrumental operation, the matrix effect, the influence and elimination of interference were discussed. In addition, the treatment and determination conditions of samples were optimized. The interference was effectively eliminated by matrix matching and off-peak background deduction. The determination results were verified using the certified reference materials prepared by high-purity reagents. The found results of indium in each component were consistent with the added values. The linear range of method was 0.0-100 mg/L. The detection limit of indium was 0.072 mg/L. The phase analysis of indium in several lead-zinc smelting dust samples was conducted. The content of indium in the form of indium oxide, indium sulfide, indium sulfate and other phases was equivalent to the total indium content. The relative standard deviations (RSDs) of total indium, indium oxide, indium sulfide and indium sulfate were between 0.96% and 7.1%. The recoveries were between 88% and 113%. The found results of actual samples were consistent with those obtained by extraction-AAS method. The proposed method was practical, rapid and applicable for the phase analysis of indium in large amounts of samples. ©, 2015, Central Iron and Steel Research Institute. All right reserved. Source
Zhang H.,Hebei University |
Han J.,Hebei University |
Tian F.,Hebei University |
Chen Q.,Hebei University |
And 4 more authors.
Research on Chemical Intermediates | Year: 2015
Abstract An efficient method was established for the green synthesis of 4-methoxybenzophenone using benzoic acid as acylating agent catalyzed by tungstophosphoric acid (HPW) supported on MCM-41 (HPW/MCM-41). The conversion of benzoic acid reached 97.2 % and the selectivity for 4-methoxybenzophenone was 87.4 % under the optimum conditions over a 50 wt.% HPW/MCM-41 catalyst. HPW is proven to be well deposited on MCM-41, which leads to dealumination of MCM-41 and then offers more active centers, as demonstrated by inductively coupled plasma analysis and NH3 temperature-programmed desorption, accounting for the high catalytic activity of HPW/MCM-41. © 2014 Springer Science+Business Media Dordrecht. Source
Wang B.,Hebei University |
Tian X.,Hebei University |
Wang Q.,Hebei Geological Laboratory |
Wang Q.,Hebei University |
And 5 more authors.
Medical Physics | Year: 2015
Purpose: Accurate detection of pulmonary nodules remains a technical challenge in computer-aided diagnosis systems because some nodules may adhere to the blood vessels or the lung wall, which have low contrast compared to the surrounding tissues. In this paper, the analysis of typical shape features of candidate nodules based on a shape constraint Chan-Vese (CV) model combined with calculation of the number of blood branches adhered to nodule candidates is proposed to reduce false positive (FP) nodules from candidate nodules. Methods: The proposed scheme consists of three major stages: (1) Segmentation of lung parenchyma from computed tomography images. (2) Extraction of candidate nodules. (3) Reduction of FP nodules. A gray level enhancement combined with a spherical shape enhancement filter is introduced to extract the candidate nodules and their sphere-like contour regions. FPs are removed by analysis of the typical shape features of nodule candidates based on the CV model using spherical constraint and by investigating the number of blood branches adhered to the candidate nodules. The constrained shapes of CV model are automatically achieved from the extracted candidate nodules. Results: The detection performance was evaluated on 127 nodules of 103 cases including three types of challenging nodules, which are juxta-pleural nodules, juxta-vascular nodules, and ground glass opacity nodules. The free-receiver operating characteristic (FROC) curve shows that the proposed method is able to detect 88% of all the nodules in the data set with 4 FPs per case. Conclusions: Evaluation shows that the authors method is feasible and effective for detection of three types of nodules in this study. © 2015 American Association of Physicists in Medicine. Source
Bai G.,Hebei University |
Wang Y.,Hebei University |
Li F.,Hebei University |
Zhao Z.,Hebei University |
And 3 more authors.
Catalysis Letters | Year: 2013
Copper-based catalysts, supported on γ-Al2O3, La2O3, and γ-Al2O3-La 2O3, respectively, were prepared by co-precipitation and tested in the continuous dehydrogenation of 2-butanol to methyl ethyl ketone. The catalytic performance of the catalysts was found to be markedly dependent on acid-base properties of the support. Three copper species were found in the calcined samples: Cu2+, [Cu-O-Cu] n cluster, and bulky CuO oxides. Cu0 was shown to be the active species of the reduced copper-based catalysts. The synergistic effect between γ-Al 2O3 and La2O3 when used as a support for well dispersed Cu0 gave the system with the best activity and stability; whereas, loss of the active Cu0 during the reaction was believed to be the main reason for Cu-La2O3 deactivation. Moreover, a possible reaction mechanism was proposed based on GC-MS results. Graphical Abstract: [Figure not available: see fulltext.] © 2012 Springer Science+Business Media New York. Source