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Son, Jungwoo,Cho, Seunggi,Lee, Chongmok,Lee, Youngmi,Shim, Jun Ho American Chemical Society 2014 Langmuir Vol.30 No.12
<P>This paper reports the facile synthesis and characterization of spongelike nanoporous Pd (snPd) and Pd/Au (snPd/Au) prepared by a tailored galvanic replacement reaction (GRR). Initially, a large amount of Co particles as sacrificial templates was electrodeposited onto the glassy carbon surface using a cyclic voltammetric method. This is the key step to the subsequent fabrication of the snPd/Au (or snPd) architectures by a surface replacement reaction. Using Co films as sacrificial templates, snPd/Au catalysts were prepared through a two-step GRR technique. In the first step, the Pd metal precursor (at different concentrations), K<SUB>2</SUB>PdCl<SUB>4</SUB>, reacted spontaneously to the formed Co frames through the GRR, resulting in a snPd series. snPd/Au was then prepared via the second GRR between snPd (prepared with 27.5 mM Pd precursor) and Au precursor (10 mM HAuCl<SUB>4</SUB>). The morphology and surface area of the prepared snPd series and snPd/Au were characterized using spectroscopic and electrochemical methods. Rotating disk electrode (RDE) experiments for oxygen reduction in 0.1 M NaOH showed that the snPd/Au has higher catalytic activity than snPd and the commercial Pd-20/C and Pt-20/C catalysts. Rotating ring-disk electrode (RRDE) experiments reconfirmed that four electrons were involved in the electrocatalytic reduction of oxygen at the snPd/Au. Furthermore, RDE voltammetry for the H<SUB>2</SUB>O<SUB>2</SUB> oxidation/reduction was used to monitor the catalytic activity of snPd/Au. The amperometric <I>i</I>–<I>t</I> curves of the snPd/Au catalyst for a H<SUB>2</SUB>O<SUB>2</SUB> electrochemical reaction revealed the possibility of applications as a H<SUB>2</SUB>O<SUB>2</SUB> oxidation/reduction sensor with high sensitivity (0.98 mA mM<SUP>–1</SUP> cm<SUP>–2</SUP> (<I>r</I> = 0.9997) for H<SUB>2</SUB>O<SUB>2</SUB> oxidation and −0.95 mA mM<SUP>–1</SUP> cm<SUP>–2</SUP> (<I>r</I> = 0.9997) for H<SUB>2</SUB>O<SUB>2</SUB> reduction), low detection limit (1.0 μM), and a rapid response (<∼1.5 s).</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2014/langd5.2014.30.issue-12/la4047947/production/images/medium/la-2013-047947_0011.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la4047947'>ACS Electronic Supporting Info</A></P>
An Establishment of Super Wi-Fi Environment in Ships Based on UHF System of TMS
( Jungwoo Kim ),( Jooyoung Son ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.5
Ships built today are larger in scale and feature more complex structures. The ever-evolving systems used on board a ship require vast amounts of data processing. In the future, with the advent of smart ships, unmanned ships and other next-generation ships, the volumes of data to be processed will continue to increase. Yet, to date, ship data has been processed using wired networks. Placed at fixed locations, the nodes on wired networks often fail to process data from mobile devices. Despite many attempts made to use Wi-Fi on ships just as on land to create wireless networks, Wi-Fi has hardly been available due to the complex metal structures of ships. Therefore, Wi-Fi on ships has been patchy as the ship-wide total Wi-Fi coverage has not properly implemented. A new ship-wide wireless network environment is part of the technology conducive to the shipbuilding industry. The wireless network environment should not only serve the purpose of communication but also be able to manage and control multiple features in real-time: fault diagnostics, tracking, accident prevention and safety management. To better understand the characteristics of wireless frequencies for ships, this paper tests the widely used TETRA, UHF and Wi-Fi and sheds light on the features, advantages and disadvantages of each technology in ship settings. The proposed deployment of a Super Wi-Fi network leveraging the legacy UHF system of TMS generates a ship-wide wireless network environment. The experimental findings corroborate the feasibility of the proposed ship-wide Super Wi-Fi network environment.