Thermally stable current-collecting silver grid coated with ceramic-capping layer for low-temperature solid oxide fuel cells

Hong, Soonwook,Lim, Yonghyun,Prinz, Fritz B.,Kim, Young-Beom Elsevier 2018 CERAMICS INTERNATIONAL Vol.44 No.18

<P><B>Abstract</B></P> <P>In an effort to decrease the operating temperature of solid oxide fuel cells (SOFCs), nano-porous thin Pt layers have been used as a cathode material with catalytic activity. Because of porous and thin characteristic of the Pt cathode, however, a large cathode area results in a significant performance deterioration because of the increased sheet resistance of the Pt cathode. In this study, we developed a Ag-patterned grid as a current-collecting layer and a samaria-doped ceria (SDC) oxide-capping layer on the porous Pt cathode to decrease sheet resistance and enhance electrochemical performance. Enhanced electron transportation and thermo-stable behavior of fabricated fuel cells indicated three-fold enhanced peak power density and more than two-fold thermomechanical stability, as per scanning electron microscopy (SEM) and electrochemical analysis results.</P>

Grain-Controlled Gadolinia-Doped Ceria (GDC) Functional Layer for Interface Reaction Enhanced Low-Temperature Solid Oxide Fuel Cells

Hong, Soonwook,Yang, Hwichul,Lim, Yonghyun,Prinz, Fritz B.,Kim, Young-Beom American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.44

<P>In this Research Article, gadolinia-doped ceria (GDC), which is a highly catalyzed oxide ionic conductor, was explored to further improve oxygen surface reaction rates using a grain-controlled layer (GCL) concept. Typically, GDC materials have been used as a cathode functional layer by coating the GDC between the electrode and electrolyte to accelerate the oxygen reduction reaction (ORR). To further improve the oxygen surface kinetics of the GDC cathodic layer, we modified the grain boundary density and crystallinity developed in the GDC layer by adjusting RF power conditions during the sputtering process. This approach revealed that engineered nanograins of GDC thin films directly affected ORR kinetics by catalyzing the oxygen surface reaction rate, significantly enhancing the fuel cell performance. Using this innovative concept, the fuel cells fabricated with a GDC GCL demonstrated a peak power density of 240 mW/cm<SUP>2</SUP> at 450 °C.</P> [FIG OMISSION]</BR>

A homogeneous grain-controlled ScSZ functional layer for high performance low-temperature solid oxide fuel cells

Hong, Soonwook,Son, Jonghyun,Lim, Yonghyun,Yang, Hwichul,Prinz, Fritz B.,Kim, Young-Beom The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.34

<P>Scandia-stabilized zirconia (ScSZ) is employed as a cathodic functional layer onto yttria-stabilized zirconia based fuel cell systems for low-temperature solid oxide fuel cells. In order to overcome the relatively poor material properties in terms of surface reaction rate, the grain structure and the degree of crystallinity of ScSZ thin films were modified by controlling the RF power during the thin-film fabrication process <I>via</I> sputtering. The concept of grain-controlled layers (GCLs) was applied at the cathode-electrolyte interface to enhance the surface reaction rate by catalyzing the oxygen reduction reaction. By adopting this novel concept, the thin-film fuel cell fabricated with ScSZ GCLs could achieve a peak power density of 479 mW cm<SUP>−2</SUP> at 450 °C.</P>

Rapid surface kinetics enhancement via flash light sintering for low-temperature solid oxide fuel cells

Hong, Soonwook,Lim, Yonghyun,Lee, Hojae,Chung, Wanho,Hwang, Hyunjun,Kim, Haksung,Kim, Young-Beom Elsevier 2019 JOURNAL OF ALLOYS AND COMPOUNDS Vol.778 No.-

<P><B>Abstract</B></P> <P>“Samaria-doped ceria (SDC), with exceptional electrochemical catalyzing characteristics, is a promising material for the operating temperature of solid oxide fuel cells (SOFC). Despite its extraordinary electrochemical reactivity, its chemical unstable behavior in terms of reduction phenomenon has made its application to SOFC electrolyte challenging. In regard to the defect chemistry, however, this instability can enhance the oxygen incorporation rate at the surface of the electrolyte. Here, we report a rapid surface treating method for SDC thin films via flash light sintering, which revealed an outstanding crystallinity development with nano-grains and increment of mobile dopant cation-induced oxygen vacancies within few milliseconds. We demonstrated that the flash light sintering-induced rapid development of crystallinity and reduction of ceria increases oxygen reducing surface kinetics, leading to an improvement in the oxygen incorporation rate of the cathodic reaction in SOFCs. The performance of SOFC sintered by flash light indicated more than two-folds enhancement comparing the pristine cell.”</P> <P><B>Highlights</B></P> <P> <UL> <LI> Successful rapid flash light sintering for samaria-doped ceria thin films. </LI> <LI> Enhanced crystallinity and surface oxygen vacancy concentration of thin films. </LI> <LI> Application of samaria-doped ceria interlayer to increase surface oxygen kinetics. </LI> <LI> Two-folds enhanced performance of low-temperature SOFC. </LI> </UL> </P>

양형기준의 제정과 한계

홍순욱(Soonwook Hong) 한국법학원 2013 저스티스 Vol.- No.139

이론적ㆍ제도적으로 통제되지 않는 권한으로 보았던 전통적 법관양형권을 가장 효과적으로 통제하는 방법으로 미국연방, 영국, 한국 등은 양형기준을 제정하였다. 각국 양형기준의 형태는 다양하다. 미국연방은 계량적ㆍ수치적 양형인자 평가방법을 채택한 단일한 양형기준표을 도입하였고, 미국연방대법원의 U.S. v. Booker 판결에 따라 그 양형기준의 기속력은 권고적 효력으로 변경되었다. 영국은 서술형 양형인자 평가방법을 채택한 개별적 양형기준표를 두었고, Criminal Justice Act 2003하에서는 기속력이 없다가 Coroners and Justice Act 2009의 시행에 따라 기속력이 부여되었다. 한국은 상대적인 계량적ㆍ수치적 양형인자 평가방법을 채택한 개별적 양형기준표를 마련하였고, 그 양형기준에 기속력을 부여하지 않았다. 양형기준은 법정형보다 축소된 형량범위를 규범의 형태로 제시하고 그 새로운 형량범위에 도달하기 위한 양형인자 평가방법을 규범적으로 미리 정한 것으로, 양형인자 평가방법의 규범화는 그 평가방법의 계량화ㆍ수치화 정도가 높을수록 두드러진다. 전통적 법관양형권의 일부 영역을 규범화한 양형기준은 법률 하위의 규범에 의해 전통적 법관양형권을 재분배하는 헌법적 기능을 하므로, 그 헌법적 정당성은 권력분립의 원칙과 법률 하위의 규범제정에 관한 헌법조항을 검토해야 한다. 한국헌법질서 하에서, 사법부 이외의 기관에 속한 양형위원회가 양형기준을 제정하는 것은 그 기속력의 강약에 관계없이 사법부의 자율성, 온전성을 침해하여 헌법위반에 해당할 가능성이 높다. 계량적ㆍ수치적 양형인자 평가방법을 도입하는 것이 적절한지에 관하여 많은 논의가 있으나 그 헌법적합성은 권력분립의 원칙에 따라 판단해야 하며, 계량적ㆍ수치적 양형인자 평가방법을 담은 양형기준에 기속력이 강하다면 그 양형기준은 법관양형권의 핵심영역을 침해한다. 양형은 경직되고 기계적이거나 과학적인 과정이 될 수 없으며, 양형기준은 양형의 균등성, 양형의 투명성과 개별 사건 양형의 적정성을 모두 담보할 수 있도록 제정되어야 한다. The United States, the United Kingdom and South Korea adopted sentencing guidelines in order to restrict traditionally acknowledged judicial discretion in sentencing. Although the forms of sentencing guidelines in each country are different, they all have application method, new range of the sentences, guidance of estimating sentencing factor. Sentencing guideline is not only procedural but also substantive, and results in reallocation of sentencing power and legislative restriction on judicial discretion in sentencing. Therefore, sentencing guideline is to be under Constitutional Principles such as division of powers, due process of law, etc. In conclusion, under Korean Constitution, sentencing guideline enacted by the non-judicial institution can be unconstitutional. To be specific, mandatory(presumptive) sentencing guideline with rigid formula in estimating factor violates the essential part of judicial discretion in sentencing. Secondly, mandatory-narrative or advisory-numerical sentencing guideline is less unconstitutional. Lastly, advisory-narrative sentencing guideline is constitutional. Sentencing is a complex and difficult exercise which can never be done through a rigid, mechanistic or scientific process. Sentencing guideline should not only guarantee consistency of sentencing, but also help judges decide the appropriate sentence for an individual criminal offence.

임직원 평균근속연수와 기업가치의 관계

홍순욱(Soonwook Hong) 한국관리회계학회 2016 관리회계연구 Vol.16 No.2

본 연구는 기업의 임직원 평균근속연수가 기업가치에 미치는 영향을 분석하는데 목적이 있다. 일반적으로 임직원의 근속연수가 길어질수록 숙련도가 쌓여 생산성은 높아지고, 임금은 상승한다고 알려져 있다. 국내 기업은 연공성이 강한 임금구조로 미국 등 다른 선진국에 비해 근속연수가 길어질수록 임금상승률이 훨씬 크다. 이러한 임금 상승에 비례해서 임직원의 생산성이 높아진다면 기업의 가치도 상승할 것이다. 하지만 여러 조사 자료에서 국내 기업의 임금 상승률은 생산성 상승률을 초과한다고 보고하고 있다. 본 논문의 표본은 2005년부터 2014년까지 유가증권시장에 상장된 5,428개(기업․연도)의 비금융업 기업을 대상으로 한다. 기업가치의 대용치로 Tobin’s Q, MTB, 종업원 1인당 부가가치, 종업원 1인당 당기순이익을 사용하였다. 분석결과 기업의 임직원 평균근속연수와 기업가치는 음(-)의 관계가 있는 것으로 보인다. 임직원 평균근속연수는 기업연령 및 산업과 밀접한 관련이 있어, 기업연령과 산업에 따른 효과를 배제하고자 다양한 추가 분석을 실시하였으며 추가 분석 결과도 본 분석의 결과와 다르지 않았다. 본 연구의 시사점은 첫째, 임직원 평균근속연수와 기업가치의 관련성을 검증했다는 것이다. 임직원 평균근속연수는 최근 사회적 이슈로 대두되고 있는 인력 구조조정과 일정 부분 관련이 있을 것으로 추측된다. 둘째, 그동안 기업의 경영자와 관련한 연구는 많이 수행되었으나 임직원 전체를 대상으로 한 연구는 거의 없다는 점에서도 공헌점이 있다. 더불어 Ohlson(1995)이 던져준 과제인 기업가치에 영향을 미치는 비 회계정보 중 하나로 임직원 평균근속연수의 가치 관련성 발견도 공헌하는 바가 있다 하겠다. The purpose of this study is to examine the effect of the average length of service on firm value. It is generally known that employees with longer years of service show higher productivity and their wages increase accordingly. The wage growth rate in Korea is a lot higher than other developed countries such as the United States, since the Korean companies give strong credit for long and meritorious service. Firm value should be increasing if employees perform better as the wages gets higher. However, several research data show that the wage growth rate exceeds the productivity increasing rate in Korea. This research analyzes 5,428 non-financial listed companies from year 2005 to 2014 to test the relationship between the average length of service of employees and firm value. As a proxy of firm value Tobin’s Q, MTB(Market To Book), VAPC(Value Added Per Capita), NIPC(Net Income Per Capita) were used. The result shows the negative relationship between the average length of service and firm value and it appears to support the firms’ decision. Moreover, since the average length of service is closely linked to firm age, various analyses were conducted additionally to exclude that effect and they indicate the similar outcome. The contribution of this research is that it verifies the relationship between the average length of service and firm value. The average length of service is assumed to be somewhat related to the redundancy for restructuring which is the rising social issue. There were little prior studies that investigated the total employees of firms while there were a lot of studies that investigated the CEO of firms. Ohlson(1995) has threw a question of what the non-accounting information that influences firm value is. This research also has its implication that it found the value relevance of the average length of service as one of the answers.

Autonomic dysfunction in multiple sclerosis and neuromyelitis optica spectrum disorder

Soonwook Kwon,Ju-Hong Min 대한임상신경생리학회 2023 Annals of Clinical Neurophysiology Vol.25 No.1

Autonomic dysfunction occurs frequently in multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). Patients with either condition may present with autonomic symptoms such as bladder, sexual, cardiovascular, thermoregulatory, and gastrointestinal dysfunction, and fatigue, but autonomic symptoms that affect quality of life are underrecognized in clinical practice. The immunopathogenesis of MS has been considered to be associated with autonomic dysfunction. Applying appropriate treatment strategies for autonomic dysfunction is important to improve the quality of life of patients. Here we review autonomic dysfunction and how this is managed in patients with MS and NMOSD.

Automatic classification of otoscopic images using deep learning

Soonwook Kwon,Muhammed Azam Khan,Jaegul Choo,Sukjin Hong 대한체질인류학회 2019 대한체질인류학회 학술대회 연제 초록 Vol.62 No.-

Analysis of dural sac thickness in the human cervical spine

Kwon, Soonwook,Suh, Seung-Woo,Kim, Dasom,Rhyu, Im Joo,Yu, Hyunung,Han, Seung Woo,Hong, Jae-Young Springer-Verlag 2018 Anatomical science international Vol.93 No.2

<P>The thickness of the dura mater in the human cervical spine can vary between individuals and by vertebral level; these differences can result in various clinical outcomes. The purpose was to measure and analyze cervical dura mater thickness. Microscopic measurements were made of tissue from human cadavers. The subjects were nine human cadavers with no previous history of spinal deformity or surgery. Fourteen segments of both anterior and posterior dura mater from the C1 to C7 cervical vertebrae were obtained. Dura mater thickness was measured using an infrared laser-based confocal microscope. Statistical analyses were performed to examine the relationships of cervical dura mater thickness with vertebral level, age, and sex. The overall average cervical dura mater thickness was 379.3 x 10(-3) mm. Statistically significant differences in thickness were found between the anterior and posterior segments (P < 0.0001). Moreover, the thickness at each vertebral level was significantly different from the thicknesses at the other levels (P < 0.05). The posterior dura mater thickness was highest at C1 and lowest at C5/6. Posterior dura mater thickness was significantly different at the axial, sub-axial, and lower cervical levels, whereas anterior dura mater thickness was relatively constant among levels. A significant correlation was found between thickness and age (P < 0.05); however, the average dura mater thickness was not significantly different between males and females. This study shows anatomical differences in cervical dura mater thickness with respect to vertebral level and age. These results provide anatomical information that will inform basic research and clinical approaches.</P>

High-performance reverse electrowetting energy harvesting using atomic-layer-deposited dielectric film

Yang, Hwichul,Hong, Soonwook,Koo, Bongjun,Lee, Dohaeng,Kim, Young-Beom Elsevier 2017 Nano energy Vol.31 No.-

<P><B>Abstract</B></P> <P>Reverse electrowetting-on-dielectric (REWOD), which is a novel technology for energy harvesting, was demonstrated by depositing Al<SUB>2</SUB>O<SUB>3</SUB> via atomic layer deposition (ALD). Specifically, thin layers of Al<SUB>2</SUB>O<SUB>3</SUB> about 100nm-thick were successfully formed by ALD to obtain dense films with high capacitances. REWOD with the ALD Al<SUB>2</SUB>O<SUB>3</SUB> thin films exhibited high performances under low-voltage and low-excitation-frequency conditions. The maximum power density was 11mW/cm<SUP>2</SUP> with a DC bias of 24V and an external excitation frequency of 2Hz. Moreover, ALD and sputtered thin films were compared by investigating their capacitances and leakage current densities. Due to the differences between the film densities and growth methods, the ALD thin films exhibited higher capacitances and lower leakage current densities. It was also determined that the leakage current affects the REWOD energy harvesting performance. By analyzing these features, it was confirmed that ALD thin films are suitable for REWOD energy harvesting.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Highly dense ultra-thin dielectric layer was fabricated for capacitive applications. </LI> <LI> High-performance of REWOD energy harvesting was demonstrated. </LI> <LI> Superior dielectric properties were obtained using a common oxide material. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>High performance reverse electrowetting on dielectric device utilizing superior dielectric layer fabricated by atomic layer deposition.</P> <P>[DISPLAY OMISSION]</P>