Search

Your search keyword '"Chen, Qing‐Yun"' showing total 125 results
Start Over Author "Chen, Qing‐Yun" Search Limiters Full Text
125 results on '"Chen, Qing‐Yun"'

5. Ab initio density functional theory study of uranium solubility in Gd2Zr2O7 pyrochlore

Author

Chen, Qing-yun, Shih, Kai-min, Meng, Chuan-min, Liao, Chang-zhong, Wang, Lie-lin, Xie, Hua, Lv, Hui-yi, Wu, Tao, Ji, Shi-yin, and Huang, Yu-zhu

Subjects
Condensed Matter - Materials Science, Physics - Computational Physics
Abstract

In this study, an ab initio calculation is performed to investigate the uranium solubility in different sites of Gd2Zr2O7 pyrochlore. The Gd2Zr2O7 maintains its pyrochlore structure at low uranium dopant levels, and the lattice constants of Gd2(Zr2-yUy)O7 and (Gd2-yUy)Zr2O7 are generally expressed as being linearly related to the uranium content y. Uranium is found to be a preferable substitute for the B-site gadolinium atoms in cation-disordered Gd2Zr2O7 (where gadolinium and zirconium atoms are swapped) over the A-site gadolinium atoms in ordered Gd2Zr2O7 due to the lower total energy of (Gd2-yZry)(Zr2-yUy)O7. The theoretical findings present a reasonable explanation of recent experiment results.

Published
2015

8. Progress of Diamond-like Carbon Films

Author

CHEN Qing-yun, SHI Kai-min, SU Min-hua, LYU Hui-yi, LUO Yu, and ZENG Chen

Subjects
diamond-like carbon, deposition mechanism, adhesion, tribological property, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

Diamond-like carbon(DLC) films had many unique and outstanding properties such as high thermal conductivity, high hardness, excellent chemical inertness, low friction coefficients and wear coefficients. The properties and combinations were very promising for heat sink, micro-electromechanical devices, radiation hardening, biomedical devices, automotive industry and other technical applications, more research and a lot of attention were attracted in recent years. The research progress of diamond-like films and the nucleation mechanism of film were summarized, and application prospect of DLC films were demonstrated. The aim of this paper is to provide insights on the research trend of DLC films and the industry applications.

Published
2017
Full Text
View/download PDF

9. Regioselective Syntheses of 2- and 4-Formylpyrido[2,1-b]benzoxazoles

Author

Li, Ke-Lai, Du, Zong-Bo, Guo, Can-Cheng, and Chen, Qing-Yun

Abstract

o-Acetaminophenols (2) reacted with Vilsmeier reagent under Meth-Cohn conditions to yield 2-formylpyrido[2,1-b]benzoxazoles (5) unexpectedly besides the known compounds 2-(benzoxazol-2′-yl)-3-dimethylaminoacroleins (4). Refluxing 4in acetic anhydride gave 4-formylpyrido[2,1-b]benzoxazoles (6), an isomer of 5. Both 5aand 6awere structurally characterized by X-ray crystallography. A mechanism for the formation of 5involving sequential chlorination, dimerization, intramolecular elimination of HCl to form the oxazole ring, formylation twice, and regioselective intramolecular nucleophilic cyclization to construct the pyridone ring is proposed.

Published
2024
Full Text
View/download PDF

16. Metal Recovery and Electricity Generation from Wastewater Treatment: The State of the Art.

Author

Chen, Qing-Yun, Lu, Ruo-Chen, Zhu, Yu-Cheng, and Wang, Yun-Hai

Subjects
WASTEWATER treatment, ELECTRIC power production, MICROBIAL fuel cells, WASTE recycling, FUEL cells
Abstract

The recovery of metal resources from wastewater is very important for both resource recovery and wastewater treatment. Compared with traditional metal-polluted wastewater treatment technologies, advanced wastewater treatment technologies with the functions of both recovering metals and generating electricity have been developed rapidly in recent years. These advanced technologies include microbial fuel cells, photo fuel cells, coupled redox fuel cells, etc. In this paper, these advanced technologies are elaborated from their principles to their applications in wastewater treatment for metals recovery and electricity generation. The recent progress of these technologies was also reviewed. The effects of different metal ions, cell configurations, and various operating parameters on their performance were also discussed. Although these technologies are promising, the challenges and the efforts needed to overcome them are also highlighted. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

19. Tumor Fibroblast–Derived FGF2 Regulates Expression of SPRY1 in Esophageal Tumor–Infiltrating T Cells and Plays a Role in T-cell Exhaustion

Author

Chen, Qing-yun, primary, Li, Yi-ni, additional, Wang, Xin-yue, additional, Zhang, Xu, additional, Hu, Yi, additional, Li, Lei, additional, Suo, Da-qin, additional, Ni, Ke, additional, Li, Zhuo, additional, Zhan, Jia-rong, additional, Zeng, Ting-ting, additional, Zhu, Ying-hui, additional, Li, Yan, additional, Ma, Li-jia, additional, and Guan, Xin-Yuan, additional

Published
2020
Full Text
View/download PDF

21. The activation of carbon-chlorine bonds in per- and polyfluoroalkyl chlorides: DMSO-induced hydroperfluoroalkylation of alkenes and alkynes with sodium dithionite

Author

Long, Zheng-Yu and Chen, Qing-Yun

Subjects
Chemical reactions -- Research, Chlorides -- Research, Dimethyl sulfoxide -- Usage, Solution (Chemistry) -- Case studies, Biological sciences, Chemistry
Abstract

A study presents a new, practical hydroperfluoroalkylation technique of alkenes and alkynes with perfluroalkyl chlorides in the presence of sodium dithionite. Furthermore, perfluoroalkanesulfinates and sulfonyl chlorides can be prepared directly from available perfluoroalkyl chlorides. The solvent dimethyl sulfoxide plays a unique role in these reactions. Experimental methodology, findings and conclusions are discussed.

Published
1999

22. A new and improved synthesis of trans-1,2-diiodoalkenes and their stereospecific and highly regioselective trifluoromethylation

Author

Duan, Jianxin, Dolbier, William, Jr., and Chen, Qing-Yun

Subjects
Olefins -- Research, Stereochemistry -- Research, Methylation -- Research, Organic compounds -- Synthesis, Biological sciences, Chemistry
Abstract

A study was conducted to analyze a novel synthesis of trans-1,2-diiodoalkenes and their stereospecific and highly regioselective trifluoromethylation. The iodination of alkynes were carried out by adding a mixture of acetonitrile, alkyne and CuI in a flask. Results indicated the possibility of replacing the iodo substituent at the terminal position during the substitution of diiodoalkene by an aryl or carboethoxy group.

Published
1998

23. Pentafluorophenylation of aromatics with pentafluoronphenyl perfluoro- and polyfluoroalkanesulfonates. A photoinduced electron-transfer cation diradical coupling process

Author

Chen, Qing-Yun and Li, Zhan-Ting

Subjects
Aromatic compounds, Electron transport -- Research, Radicals (Chemistry) -- Research, Biological sciences, Chemistry
Abstract

Phenylation of aromatic compounds are discussed in terms of regioisomer yield. Pentafluorophenyl perfluoro- and poly-fluoroalkanesulfonates were irradiated in aromatic compounds including benzene, toluene, m- or p-xylene, isopropylbenzene and mesitylene. It is suggested that the mechanism involves an initial photoinduced electron transfer process followed by a proton transfer to produce a radical pair. However, this depends on the aromatic compound used.

Published
1993

33. Anodic Materials for Electrocatalytic Ozone Generation

Author

Wang, Yun-Hai and Chen, Qing-Yun

Subjects
Article Subject
Abstract

Ozone has wide applications in various fields. Electrocatalytic ozone generation technology as an alternative method to produce ozone is attractive. Anodic materials have significant effect on the ozone generation efficiency. The research progress on anodic materials for electrocatalytic ozone generation including the cell configuration and mechanism is addressed in this review. The lead dioxide and nickel-antimony-doped tin dioxide anode materials are introduced in detail, including their structure, property, and preparation. Advantages and disadvantages of different anode materials are also discussed.

Published
2013
Full Text
View/download PDF

34. Anodic Materials with High Energy Efficiency for Electrochemical Oxidation of Toxic Organics in Waste Water

Author

Chen Qing-Yun, Li Guo, Li Xiang-Lin, and Wang Yun-Hai

Subjects
High energy, Materials science, Wastewater, Waste management, Reagent, Oxidizing agent, System configuration, Electrochemistry, Environmentally friendly, Anode
Abstract

With the development of human society, discharge of toxic organics in industrial waste water increased sharply. It is difficult to treat these types of waste water efficiently by traditional bio-process to meet the more critical discharge standard. Advanced oxidation processes (AOPs) attracted more and more attention as efficient methods to remove the toxic organics from waste water. Compared with other AOPs, electrochemical oxidation process was considered as an effective and environmental friendly process due to its simplicity in operation, robustness in system configuration, strong oxidizing ability, reliable performance for a wide variety of toxic organics and chemical reagents free.

Published
2012

35. Phenol degradation on novel nickel-antimony doped tin dioxide electrode

Author

Wang Yun-Hai, Zhang Yuan-Jun, Chen Qing-Yun, and Shi Dong-Dong

Subjects
Antimony, Environmental Engineering, Materials science, Ozone, Inorganic chemistry, chemistry.chemical_element, Electrochemistry, Waste Disposal, Fluid, law.invention, Water Purification, chemistry.chemical_compound, Phenols, law, Nickel, Electrodes, Water Science and Technology, Titanium, Electrolysis, Tin dioxide, Tin Compounds, Sulfuric acid, Anode, chemistry, Microscopy, Electron, Scanning, Water Pollutants, Chemical
Abstract

Nickel and antimony doped tin dioxide is a novel anodic material for its good performance of electrochemical ozone generation and direct electro-catalytic oxidation. Electro-catalytic oxidation of phenol on this novel nickel-antimony doped tin dioxide electrode is presented here. The morphology and composition of the electrode are characterized. The effects of applied current densities on phenol degradation rate, energy consumption and coulomb efficiency are discussed. In 0.1 M sulfuric acid, after 4 h electrolysis with current density of 25 mA cm−1, 90% phenol is removed. And with current density of 20 mA cm−1, the highest energy efficiency of 6.85 g kWh−1 and the highest coulomb efficiency of 6.87 μg C−1 are obtained. The effect of current densities on TOC removal is also discussed.

Published
2010

49. The structures and properties of Ge nanocrystals before and after Neutron transmutation doping

Author

Chen Qing-Yun, Lu Tie-Cheng, Meng Chuan-Min, Hu You-Wen, and Xu Ming

Subjects
Crystallography, Materials science, Condensed matter physics, Nanocrystal, Doping, General Physics and Astronomy, Density functional theory, Neutron transmutation doping, Luminescence, Neutron irradiation
Abstract

The effects of vacant, O defects and As doping on the structures and properties of Ge nanocrystals (Ge-ncs) are investigated by using first-principles calculation based on the density functional theory (DFT). The calculation results indicate that the O defects induced by thermal annealing cannot compensate for the defects caused by neutron irradiation in Ge nanocrystals, while the introduction of As produced by neutron transmutation doping (NTD) will do the jop. We also show that the strong attraction between O and Ge atoms inhibits the formation of vacant defects in Ge nanocrystals, and further improve the luminescent property of Ge-SiO2 system. This suggests that it is necessary to perform thermal annealing for Ge-ncs structures before NTD. Our calculations well support our previous experimental results.

Published
2010

Catalog

Books, media, physical & digital resources
See catalog results