Single crystalline zinc structures synthesized spontaneously in solution

Cho, Seungho,Lee, Kun-Hong Royal Society of Chemistry 2010 Journal of materials chemistry Vol.20 No.33

<P>We report a method for the synthesis of Zn structures with a variety of morphologies through a spontaneous solution phase reaction without application of an electropotential under ambient conditions. We also describe, in detail, the influence of several experimental conditions on the morphology and microstructure of the Zn structures. The morphology of the Zn structures transitioned from hexagonal disks to dendritic forms as the reaction temperature was increased due to an increase in the driving force for Zn structure formation (over a temperature range from room temperature, 22 °C, to 95 °C). The size of the Zn structures was controlled by adjusting the concentration of zinc acetate dihydrate added to the reaction solution. When the concentration of zinc salt was reduced, smaller Zn structures were synthesized. Control experiments revealed that the aluminium layer, ammonia additions, and ammonia concentration were key factors for the formation of Zn metal structures. A zinc ion complex, Zn(NH<SUB>3</SUB>)<SUB>4</SUB><SUP>2+</SUP>, played a critical role in the formation of the Zn structures. Zn nanowires were synthesized in the presence of a 1.5 μm thick Al layer substrate. Based on these observations, we propose possible formation mechanisms for the spontaneous assembly of the various Zn structures.</P> <P>Graphic Abstract</P><P>Single crystalline zinc structures with a variety of morphologies were synthesized through a spontaneous solution phase reaction. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0jm00969e'> </P>

An exceptionally facile method to produce layered double hydroxides on a conducting substrate and their application for solar water splitting without an external bias

Cho, Seungho,Jang, Ji-Wook,Park, Yoon Bin,Kim, Jae Young,Magesh, Ganesan,Kim, Jin Hyun,Seol, Minsu,Yong, Kijung,Lee, Kun-Hong,Lee, Jae Sung The Royal Society of Chemistry 2014 ENERGY AND ENVIRONMENTAL SCIENCE Vol.7 No.7

<P>An exceptionally facile process is presented for <I>in situ</I> formation of zinc chromium layered double hydroxide (ZnCr:LDH) nanosheets on a conducting substrate. Thus, ZnCr:LDH nanosheets were synthesized from a metallic Zn film/fluorine-doped tin oxide (FTO) glass by simply dipping into a Cr nitrate solution for only one minute at room temperature. Then, ZnCr:LDHs were converted into zinc chromium mixed metal oxide (ZnCr:MMO) nanoparticles by calcination. Under visible light irradiation (<I>λ</I> > 420 nm), the <I>in situ</I> synthesized ZnCr:MMO photoanode exhibited a stable and an order-of-magnitude higher activity for photoelectrochemical water splitting than that of a ZnCr:MMO film fabricated <I>ex situ</I> by electrophoretic deposition of already-synthesized ZnCr:MMO powders. More significant was that it generated anodic photocurrents even without an externally applied bias potential, which is an unprecedented result for an oxide photoanode-driven PEC system working under visible light.</P> <P>Graphic Abstract</P><P>A photoanode derived from layered double hydroxide is applied for bias-free solar water splitting. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3ee43965h'> </P>

The Difference between News Coverage and News Release of Political Parties During A Political Crisis

SeungHo Cho(조승호) 한국콘텐츠학회 2018 한국콘텐츠학회논문지 Vol.18 No.11

본 연구의 목적은 정치적 위기 상황에서 위기대응에 대한 언론보도와 정당의 차이를 조사하는 것이다. 과거 정치적 사례를 통해 정치적 상황, 정치적 집단의 위기대응, 언론보도를 살펴보았다. 본 연구가 살펴본 사례는 16대 대통령 선거운동에서 불법 선거자금 모금과 관련해서 두 정당(새천년민주당 vs. 한나라당)의 대응이다. 두 정당은 그들의 이미지 회복을 위한 위기대응 전략을 활용하였다. 본 연구는 위기대응메시지와 언론보도 메시지의 차이를 내용분석을 통해서 살펴보았다. 그 결과 특정 정당의 위기대응 메시지와 뉴스미디어는 차이를 보이지 않았으나, 다른 정당의 경우는 차이가 나타났다. 이러한 뉴스보도와 정당의 메시지 일치 여부는 공중의 위기평가에 중요한 영향을 미친다. 본 연구는 위기커뮤니케이션에서 조직의 위기대응 메시지와 뉴스미디어의 보도 차이의 중요성을 다뤘다는 점에서 의의를 갖는다. The purpose of this study is to explore a difference in crisis between media and parties. This research examined political crisis situation, crisis response, and media coverage using a case. Two main political parties in Korean faced the illegal fund raising case during the 16th presidential election. They used types of crisis response strategies for restoring or maintaining their reputation. This study found that a party’s crisis response was consistent with news media, but another party’s message was significantly different from news media. Such match or mismatch between a party and news media will influence on public evaluation toward a crisis response. This study has meaningful contribution in that the difference between an organizational crisis response message and news media coverage is significant.

Three-Dimensional Type II ZnO/ZnSe Heterostructures and Their Visible Light Photocatalytic Activities

Cho, Seungho,Jang, Ji-Wook,Kim, Jungwon,Lee, Jae Sung,Choi, Wonyong,Lee, Kun-Hong American Chemical Society 2011 Langmuir Vol.27 No.16

<P>We report a method for synthesizing three distinct type II 3D ZnO/ZnSe heterostructures through simple solution-based surface modification reactions in which polycrystalline ZnSe nanoparticles formed on the surfaces of single-crystalline ZnO building blocks of 3D superstructures. The experimental results suggested a possible formation mechanism for these heterostructures. The formation of the ZnO/ZnSe heterostructures was assumed to result from a dissolution–recrystallization mechanism. The optical properties of the 3D ZnO/ZnSe heterostructures were probed by UV–vis diffuse reflectance spectroscopy. The 3D ZnO/ZnSe heterostructures exhibited absorption in the visible spectral region. The visible photocatalytic activities of 3D ZnO/ZnSe heterostructures were much higher than those of the 3D pure ZnO structures. The activities of the 3D ZnO/ZnSe heterostructures varied according to the structures under visible light. The morphologies and exposed crystal faces of pure ZnO building blocks prior to surface modification had a significant effect on the visible light photocatalytic processes of ZnO/ZnSe heterostructures after surface modification.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2011/langd5.2011.27.issue-16/la201755w/production/images/medium/la-2011-01755w_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la201755w'>ACS Electronic Supporting Info</A></P>

Quantum dot-layered double hydroxide composites for near-infrared emitting codes

Cho, Seungho,Hong, Seong Cheol,Kim, Sungjee The Royal Society of Chemistry 2014 Journal of Materials Chemistry C Vol.2 No.3

Linux-based Real Time Monitoring System of Mobile Robots

SeungHo Cho,I. O. Lee,JangMyung Lee 제어로봇시스템학회 2006 제어로봇시스템학회 국제학술대회 논문집 Vol.2006 No.10

Self-Assembled Gold Nanoparticle–Mixed Metal Oxide Nanocomposites for Self-Sensitized Dye Degradation under Visible Light Irradiation

Cho, Seungho,Jang, Ji-Wook,Hwang, Sekyu,Lee, Jae Sung,Kim, Sungjee American Chemical Society 2012 Langmuir Vol.28 No.50

<P>Gold nanoparticle (Au NP)–mixed metal oxide (MMO) nanocomposite photocatalysts for efficient self-sensitized dye degradations under visible light were prepared by an electrostatically driven self-assembly. Dihydrolipoic acid (DHLA)-capped Au NPs (building block I) were synthesized through a room temperature reaction. Their hydrodynamic size was determined as being around 4.9 nm by dynamic light scattering measurements. MMO nanoplates with lateral dimensions of 100–250 nm (building block II) were prepared by a calcination of zinc aluminum layered double hydroxides at 750 °C for 2 h in air. In a pH 7.0 aqueous solution, the DHLA-capped Au NPs had a negative zeta potential (−22 ± 3 mV); on the other hand, the MMO nanoplates had a positive zeta potential (15 ± 2 mV). Electrostatic self-assembly was achieved by stirring an aqueous solution (pH 7.0) containing DHLA-capped Au NPs and MMO nanoplates at room temperature for 1 h. The self-assembled and sequentially calcined nanocomposites exhibited the superior self-sensitized dye degradation efficiency under visible light to that of ZnO, TiO<SUB>2</SUB> (P25), or pure MMO nanoplates. The enhanced degradation efficiency could be attributed to strong coupling interactions of ZnO and ZnAl<SUB>2</SUB>O<SUB>4</SUB> phases of the MMO and the role of Au as an electron sink and mediator for formations of reactive oxidation species and as a light concentrator.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2012/langd5.2012.28.issue-50/la304303h/production/images/medium/la-2012-04303h_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la304303h'>ACS Electronic Supporting Info</A></P>

The Interaction between Personality Characteristics and Mood States in Media Contents Selection

Cho, Seungho,Hur, Junsoo The Korea Contents Association 2018 International Journal of Contents Vol.14 No.4

This study was conducted to explore the relationship between personality characteristics and mood in the selection of media content. Using meta-analysis, this study analyzed past studies regarding media content selection in television program. The results of this research showed that the preference of a given media content would depend on the viewer's mood, personality characteristics and the interaction between personality characteristics and mood states. The secondary data of television programs supported the association.

Large-Scale Fabrication of Sub-20-nm-Diameter ZnO Nanorod Arrays at Room Temperature and Their Photocatalytic Activity

Cho, Seungho,Kim, Semi,Jang, Ji-Wook,Jung, Seung-Ho,Oh, Eugene,Lee, Bo Ram,Lee, Kun-Hong American Chemical Society 2009 The Journal of Physical Chemistry Part C Vol.113 No.24

Strongly enhanced dielectric and energy storage properties in lead-free perovskite titanate thin films by alloying

Cho, Seungho,Yun, Chao,Kim, Yoon Seo,Wang, Han,Jian, Jie,Zhang, Wenrui,Huang, Jijie,Wang, Xuejing,Wang, Haiyan,MacManus-Driscoll, Judith L. Elsevier 2018 Nano energy Vol.45 No.-

<P><B>Abstract</B></P> <P>Lead-free perovskite oxide thin films prepared by alloying of titanates and materials with lower melting points are shown to have enhanced ferroelectric and dielectric properties. BaTiO<SUB>3</SUB> (or SrTiO<SUB>3</SUB>) with 25% addition of BiFeO<SUB>3</SUB> has much improved crystalline perfection because of the lower melting point of the BiFeO<SUB>3</SUB> giving enhanced growth kinetics. The maximum dielectric peak temperature of BaTiO<SUB>3</SUB> is increased by ~ 200°C and leakage currents are reduced by up to a factor of ~ 100. The loss tangent reduces up to 300°C, with a factor of > 14 reduction at room temperature. The dielectric breakdown strength is higher by a factor of ~ 3 (> 2200kVcm<SUP>−1</SUP>) and from room temperature up to 500°C the dielectric constant is > 1000. Also, a low variation of dielectric constant of ~ 9% from room temperature to 330°C is obtained, compared to ~ 110% for BaTiO<SUB>3</SUB>. The maximum polarization (<I>P</I> <SUB>max</SUB>) is double that of BaTiO<SUB>3</SUB>, at 125.3μCcm<SUP>−2</SUP>. The film has high energy storage densities of > 52Jcm<SUP>−3</SUP> at 2050kVcm<SUP>−1</SUP>, matching Pb-based ferroelectric films. The strongly improved performance is important for applications in energy storage and in high temperature (up to 300°C) capacitors as well as wider application in other electronic and energy technologies.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High crystallinity is achieved by mixing titanate with a lower melting point material. </LI> <LI> The film with enhanced crystallinity has strongly enhanced dielectric properties. </LI> <LI> The film has high energy storage densities of > 52Jcm<SUP>−3</SUP>, matching Pb-based films. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>