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Autonomous interfacial creation of nanostructured lead oxide
Kwon, Youngkook,Lee, Hyejin,Lee, Jaeyoung Royal Society of Chemistry 2011 Nanoscale Vol.3 No.12
<P>We first established a process for the autonomous creation of PbO nanostructures consisting of a simple three-step procedure for both the formation of Pb nanoparticles and their oxidation. Oxygen contacting aqueous media results in an autonomous conversion from electrodeposited Pb particles to PbO nanostructures; i) flower-like PbO structures are placed at the interface of water and oxygen, ii) the growth/burst of PbO nanowires in various directions is observed in the middle of water media, and iii) ultra-thin PbO nano-platelets are dominantly placed onto the substrate. A new mechanistic origin was also proposed based on experimental observations and further suggests that major requirements are essential for the autonomous creation of PbO nanostructures.</P> <P>Graphic Abstract</P><P>Interfacial creation of PbO nanostructures: Oxygen contacting aqueous media results in an autonomous conversion from electrodeposited Pb particles to PbO nanostructures. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1nr10603a'> </P>
권기양(Kwon, Kiyang),권영국(Kwon, Youngkook),정연창(Jung, Yeonchang) 새한영어영문학회 2012 새한영어영문학 Vol.54 No.4
The goal of this paper is to investigate some aspects of the use of the English adjective beautiful synchronically and diachronically through COCA and COHA. The main findings of the study are as follows. (i) beautiful is most used in FICTION of 5 genres. (ii) According to COHA, the frequency of beautiful increases rapidly in the 1820s, and reaches its highest point in the 1840s and 1850s, and then decreases continuously until 1980s. (iii) COCA shows that beautiful, as expected, combines more strongly with female nouns than other nouns. (iv) The paper examined Korean college students’ familiarity with ‘beautiful+human/kin noun’ expressions. There was a big difference in nouns such as boy, baby, child, son between COCA and the Korean college students’ responses. This result shows that Korean learners of English need to study English with focus on chunks rather than individual words.
Electrocatalytic Recycling of CO<sub>2</sub>and Small Organic Molecules
Lee, Jaeyoung,Kwon, Youngkook,Machunda, Revocatus L.,Lee, Hye Jin Wiley (John WileySons) 2009 Chemistry - An Asian Journal Vol.4 No.10
<P>As global warming directly affects the ecosystems and humankind in the 21st century, attention and efforts are continuously being made to reduce the emission of greenhouse gases, especially carbon dioxide (CO2). In addition, there have been numerous efforts to electrochemically convert CO2 gas to small organic molecules (SOMs) and vice versa. Herein, we highlight recent advances made in the electrocatalytic recycling of CO2 and SOMs including (i) the overall trend of research activities made in this area, (ii) the relations between reduction conditions and products in the aqueous phase, (iii) the challenges in the use of gas diffusion electrodes for the continuous gas phase CO2 reduction, as well as (iv) the development of state of the art hybrid techniques for industrial applications. Perspectives geared to fully exploit the potential of zero-gap cells for CO2 reduction in the gaseous phase and the high applicability on a large scale are also presented. We envision that the hybrid system for CO2 reduction supported by sustainable solar, wind, and geothermal energies and waste heat will provide a long term reduction of greenhouse gas emissions and will allow for continued use of the abundant fossil fuels by industries and/or power plants but with zero emissions.</P>
Singh, Meenesh R.,Kwon, Youngkook,Lum, Yanwei,Ager, Joel W.,Bell, Alexis T. American Chemical Society 2016 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.138 No.39
<P>Electrolyte cation size is known to influence the electrochemical reduction of CO2 over metals; however, a satisfactory explanation for this phenomenon has not been developed. We report here that these effects can be attributed to a previously unrecognized consequence of cation hydrolysis occurring in the vicinity of the cathode. With increasing cation size, the pKa for cation hydrolysis decreases and is sufficiently low for hydrated K+, Rb+, and Cs+ to serve as buffering agents. Buffering lowers the pH near the cathode, leading to an increase in the local concentration of dissolved CO2. The consequences of these changes are an increase in cathode activity, a decrease in Faradaic efficiencies for H-2 and CH4, and an increase in Faradaic efficiencies for CO, C2H4, and C2H5OH, in full agreement with experimental observations for CO2 reduction over Ag and Cu.</P>