Do Fluoride Chemicals Co.

Jiaozuo, China

Do Fluoride Chemicals Co.

Jiaozuo, China
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Braune R.,Do Fluoride Chemicals Co. | Zapfel G.,Johannes Kepler University
Computers and Operations Research | Year: 2016

Machine-based decomposition of total weighted tardiness job shops is known to be considerably more complicated than in the makespan case, mainly due to the structure of the underlying graph model and thus the arising one-machine subproblems. In fact, the effectiveness of a shifting bottleneck approach crucially depends on the employed subproblem solver. Although a sophisticated exact algorithm exists, problem instances involving more than 30 jobs are still challenging. In this paper, new heuristic approaches to subproblems of this kind are devised which rely on advanced problem-specific concepts like local optimality and dominance principles. The proposed subproblem solvers are combined with an iterated local search method for re-optimizing already scheduled machines. Computational experiments show that the final enhanced shifting bottleneck algorithms are not only applicable to job shops involving up to 100 jobs and 20 machines, but also able to improve existing results for benchmark instances. © 2015 Elsevier Ltd. All rights reserved.

Brown R.,Alcoa | Fischer J.-C.,R and D Carbon Ltd. | Xue X.,Do Fluoride Chemicals Co. | Wu L.,Do Fluoride Chemicals Co. | And 4 more authors.
TMS Light Metals | Year: 2015

Standard work aims to ensure that reliable analysis methods are available. ISO standards are commercially important and are recognised and used by suppliers and customers around the world. Reliable analysis enables the suppliers to describe their materials using common standards for well-established material properties, and the standards are a support for smelters when evaluating and comparing sources of materials. ISO Technical Committee 226 maintains 110 standards on sampling and analysis covering smelter grade alumina, smelter grade fluorides, pitch, petroleum coke and solid carbon bodies including anodes and cathodes. The main work is done through dedicated work groups, one for each of the material groups. The need for modernisation of the standards is continuous as instruments improve and raw materials change. The paper will describe the committee, the work groups, current projects and ISO work in general. The paper is co-authored by Convenors and technical experts from the work groups. Aims of this paper are; to interest potential technical experts to participate in committee projects, and to encourage metal producing companies to support the important work that their participating staff makes within the committee.

Meng J.,Zhengzhou University | Cao Y.,Zhengzhou University | Zheng G.,Hong Kong Polytechnic University | Li J.,Do Fluoride Chemicals Co. | And 3 more authors.
Materials Research Bulletin | Year: 2014

Aluminum substituted MCM-48 (Al-MCM-48) mesoporous molecular sieves was synthesized at mild temperature without using hydrothermal process. It was used for the first time to assemble the supported H3PW12O 40 (HPW) mesoporous materials with various HPW loadings. The mesoporous materials were characterized by various techniques and their catalytic activities in the green synthesis of benzoic acid were evaluated under organic solvent-free conditions. The characterizations showed that these mesoporous materials retained the cubic phase of MCM-48 and their textural parameters decreased with increasing loading of HPW. The catalytic results suggested that the supported material was an efficient catalyst for the oxidation of benzyl alcohol and benzaldehyde with 30% H2O 2. Furthermore, the sample with 35 wt% loading of 12-tungstophosphoric acid was found to show the highest activity for the oxidation of benzaldehyde under the reaction conditions. © 2014 Elsevier Ltd. All rights reserved.

Meng J.-K.,Zhengzhou University | Zhao Q.-Q.,Zhengzhou University | Ye W.-H.,Do Fluoride Chemicals Co. | Zheng G.-P.,Hong Kong Polytechnic University | And 5 more authors.
Materials Chemistry and Physics | Year: 2016

Three-dimensional (3D) α-Fe2O3 nanoparticle anchored graphene aerogel (Fe2O3@GA) composites were assembled by a hydrothermal method using Fe(OH)3 colloids and graphene oxides as starting materials. It was found that the Fe2O3 nanoparticles were uniformly embedded into the 3D networks of graphene aerogels and the resulting composites contained meso- and macro-scale pores. Remarkably, the composites possessed much higher surface area (SBET = 212.5 m2 g-1) and larger pore volume (Vp = 0.2073 cm3 g-1) than those of pure Fe2O3 (SBET = 19.8 m2 g-1, Vp = 0.1770 cm3 g-1). The Fe2O3@GA composites used as electrode materials for lithium ion batteries were demonstrated to exhibit high reversible capacity at large current densities and excellent cycling stabilities. © 2016 Elsevier B.V.

Wen S.,Yangzhou University | Zhu X.,Yangzhou University | Wu X.,Do Fluoride Chemicals Co. | Qin X.,Yangzhou University
Analytical Methods | Year: 2014

A novel procedure is presented for the speciation of Cr(iii)/Cr(vi) involving directly suspended single droplet microextraction combined with electrothermal atomic absorption spectrometry. In this method, Cr(iii) can be extracted with 1-decanol at pH 6.0 due to the formation of a hydrophobic complex, Cr(iii)-8-hydroxyquinoline (8-HQ), whereas Cr(vi) remains in the aqueous solution. The Cr(vi) concentration was calculated by subtracting the concentration of Cr(iii) from the total chromium concentration after reducing Cr(vi) to Cr(iii) by addition of hydroxylamine hydrochloride. Different factors affecting the extraction of Cr(iii), such as pH, 8-HQ concentration, stirring rate, extraction temperature and time, and interfering ions, were schematically evaluated. Under the selected conditions, the limit of detection for Cr(iii) was 0.03 ng mL-1 with a relative standard deviation of 4.7% (C = 1.0 ng mL-1, n = 5). The calibration curve was highly linear for the Cr(iii) concentration range of 0.10-2.0 ng mL-1. The proposed method was validated against certified reference materials of environmental water (GSBZ50027-94, GBW(E)080642), and successfully applied in the speciation of chromium in well and tap water samples. © The Royal Society of Chemistry 2014.

Wu M.,Zhengzhou University | Zhao Q.-Q.,Zhengzhou University | Li J.,Do Fluoride Chemicals Co. | Wu H.-Y.,Zhengzhou University | And 4 more authors.
Journal of Experimental Nanoscience | Year: 2016

Aluminum-substituted MCM-41 (Al-MCM-41) were hydrothermally synthesised and used as supports to fabricate the mesostructured H3PW12O40 (HPW) solid acid catalysts via an impregnation method. The influences of various HPW loadings on the structures of the catalysts were verified by X-ray diffraction (XRD), nitrogen physisorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible (UV–Vis) spectroscopy and Fourier-transform infrared spectroscopy (FT-IR) measurements and their acidities were evaluated by infrared of pyridine adsorption (Py-IR) and temperature-programmed desorption of ammonia (NH3-TPD) measurements. The optimisation of the reaction conditions for levulinic acid esterification with n-hexanol such as the reaction temperature and time, the reactant molar ratio, and the catalyst dosages was performed to maximise the conversion of levulinic acid. The effects of various HPW loadings on the conversion of levulinic acid were investigated under the optimised and harsh reaction conditions. The reusability of the catalysts was also investigated. The results showed that these catalysts retained the hexagonal mesoporous structure of Al-MCM-41 and the Keggin characteristic of HPW, although their textural parameters decreased with increasing loading of HPW. In particular, the catalysts were found to be efficient in the esterification of levulinic acid with n-hexanol, resulting in hexyl levulinate which could replace the petroleum-derived chemical feedstocks. © 2016 Informa UK Limited, trading as Taylor & Francis Group

Chen Z.,Zhengzhou University | Li S.,Do Fluoride Chemicals Co. | Xue F.,Zhengzhou University | Sun G.,Zhengzhou University | And 3 more authors.
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2010

Using the excellent transport properties of supercritical carbon dioxide, tetraethyl orthosilicate (TEOS) could be easily carried into the template of the cross-linked polystyrene (PS) microspheres. Through the sol-gel procedure, the TEOS penetrated into the PS microspheres was transferred into silica. After sintering these composite particles, hollow silica microspheres were obtained. Through the above method, the hollow titanium dioxide microspheres also could be synthesized. The formation mechanism of the hollow particles was discussed and the morphology of the hollow microspheres was characterized by transmission electron microscopy (TEM) and scanning electronic microscope (SEM). © 2009 Elsevier B.V. All rights reserved.

Meng J.,Zhengzhou University | Suo Y.,Zhengzhou University | Li J.,Do Fluoride Chemicals Co. | Zheng G.,Hong Kong Polytechnic University | And 4 more authors.
Materials Letters | Year: 2015

Three-dimensional nitrogen-doped graphene aerogel (N-GA) is facilely synthesized via a hydrothermal method combined with freeze drying. When it is used as an anode for lithium-ion battery, N-GA possesses larger surface area (SBET=379.1 m2 g-1), higher reversible capacity (535.3 mAh g-1 in the 100th cycle) and more stable cycling performance compared with those of pristine GA, which could result from the structural defects caused by the nitrogen doping. © 2015 Elsevier B.V. All rights reserved.

Suo Y.,Zhengzhou University | Zhao Q.-Q.,Zhengzhou University | Meng J.-K.,Zhengzhou University | Li J.,Do Fluoride Chemicals Co. | And 5 more authors.
Materials Letters | Year: 2016

A novel facile strategy was developed to prepare the Fe3O4@graphene aerogel (Fe3O4@GA) composites. Fe3O4 nanoparticles were uniformly dispersed into the 3D network of graphene aerogel and the resultant hybrid composites contained meso- and macro-scale pores with high specific surface area (276.9 m2 g-1) and large pore volume (0.3230 cm3 g-1). The electrochemical performance revealed that the Fe3O4@GA anode exhibited high reversible capacity (~941.5 mAh g-1 at a current density of 100 mA g-1), stable cycling performance, and excellent rate capability. © 2016 Elsevier B.V.

Wu M.,Zhengzhou University | Zhao Q.-Q.,Zhengzhou University | Li J.,Do Fluoride Chemicals Co. | Su X.-L.,Zhengzhou University | And 4 more authors.
Journal of Porous Materials | Year: 2016

MCM-41 was synthesized with a non-hydrothermal procedure and then used to assemble a series of supported H3PW12O40 (HPW) mesoporous catalysts. The optimization of the reaction conditions for LA esterification with ethanol, such as the reaction temperature, reaction time, the reactant molar ratio and the catalyst dosages was performed to maximize the conversion of LA over 25 wt% HPW/MCM-41 catalysts. The catalytic performance of the resultant HPW/MCM-41 catalysts was investigated. The results show that these catalysts retain the hexagonal phase of MCM-41 and the Keggin characteristic of HPW. Although their textural parameters decrease with increasing HPW loading, these catalysts still exhibit much higher specific surface area and pore volume (SBET ≥ 446 m2 g−1, VP ≥ 0.345 cm3 g−1) than that of HPW (SBET = 5 m2 g−1, VP = 0.010 cm3 g−1). LA conversion increases with increasing HPW loading and the value may reach up to 83.7 % over 45 wt% HPW/MCM-41 under the present conditions. The resultant ethyl levulinate is promising in reducing the consumption of petroleum-derived fossil fuels. © 2016 Springer Science+Business Media New York

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