Optical Properties and Field Emission of ZnO Nanorods Grown on p-Type Porous Si

Park, Taehee,Park, Eunkyung,Ahn, Juwon,Lee, Jungwoo,Lee, Jongtaek,Lee, Sang-Hwa,Kim, Jae-Yong,Yi, Whikun Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.6

N-type ZnO nanorods were grown on p-type porous silicon using a chemical bath deposition (CBD) method (p-n diode). The structure and geometry of the device were examined by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) while the optoelectronic properties were investigated by UV/Vis absorption spectrometry as well as photoluminescence and electroluminescence measurements. The field emission (FE) properties of the device were also measured and its turn-on field and current at 6 $V/{\mu}m$ were determined. In principle, the growth of ZnO nanorods on porous siicon for optoelectronic applications is possible.

A Study on the Prevention of Secondary Accidents Based on the Analysis of High-Speed Train Accidents

Eunkyung Park J-INSTITUTE 2022 International Journal of Human & Disaster Vol.7 No.2

Purpose: Railroads are public transportation used by a large number of unspecified passengers, and the vehicle itself is large and very fast, so there is a lower probability of general accidents than road traffic, but once it occurs, it leads to a major accident, causing great human and property damage. In particular, high-speed railways run-ning at 300km/h are obliged to realize the value of absolute safety, but in 2021, the number of high-speed railway accidents increased from 1 to 4 compared to the previous year, causing the reliability of railways to drop sharply. In order to prevent high-speed railway accidents through this, two aspects, primary accident prevention and secondary accident minimization, should be considered at the same time. Method: The study applied Heinrich's Law(Heinrich's Law), the principle of industrial safety, called the law of 1:29:300, in which dozens of minor accidents and hundreds of signs must appear before a major accident. In particular, it analyzed cases of high-speed railway accidents, which are major accidents among domestic railway accidents, and large-scale derailment accidents by overseas high-speed railway operators. One major accident is caused by hundreds of signs and repetitive and unconscious behaviors that cause the accident. Preemptive pre-ventive measures are needed to prevent further major accidents from occurring on high-speed railways. Results: The causes of derailment accidents among high-speed train accidents in Korea were railroad workers' insensitivity to railway safety, lack of business cooperation between workers in different occupations, and lack of KORAIL safety management system. Overseas high-speed train accidents were derailment accidents in Ger-many, China, and France, which were also caused by railroad workers' ignorance and lack of safety management systems. In order for railway safety to become an absolute value, the need for train wireless protection was emphasized not only to preemptively prevent primary accidents but also to minimize secondary accidents. Conclusion: In this paper, train wireless protection devices were considered to prevent secondary accidents among railway safety fields. The train wireless protection devices warns other train engineers nearby to take emergency measures within a 2-4km radius when the engineer of the train presses the switch of the train pro-tection device in the event of an emergency such as an accident during train operation. Railway accidents must continue to innovate the safety system for interfaces between sub-systems, so if train wireless protection devices are technically upgraded and systematic response algorithms are developed and applied to railway sites, it will be possible to block the "1" major accidents referred to in Heinrich's Law. In the future, empirical research on the contents of the study more requires experimental application considering the railway operation organization and operating environment.

Application of nanofiltration pretreatment to remove divalent ions for economical seawater reverse osmosis desalination

Park, Minho,Park, Jongkwan,Lee, Eunkyung,Khim, Jeehyeong,Cho, Jaeweon Informa UK (Taylor Francis) 2016 Desalination and Water Treatment Vol.57 No.44

<P>To minimize scale formation potential in the applications of reverse osmosis (RO) membranes as a pretreatment unit, relatively loose nanofiltration (NF) membrane systems coupled with ultrafiltration (UF) were used to remove divalent ions from seawater. However, the UF did not reject any ions because of pore size. The rejection of divalent ions by NF was in order of sulfate (>95%), magnesium (>60%), and calcium (>30%) in every rejection experiment based on water recovery rate (40, 50, 60, 70, and 80%). In the UF/NF/RO hybrid pilot system, most of the divalent (>99%) and the monovalent (>97%) ions were effectively rejected with slightly increased divalent ion rejection compared to the UF/RO system. Seawater temperature influenced rejection of ions with regards to either the diffusion- or convection-dominant transport of ions through the membrane pores. Electric power consumption was also compared between the UF/NF/RO process and the UF/RO process. For different salinity conditions (28,000 and 45,000mg/L of total dissolved solids), the lowest energy consumption by NF/RO was 3.3 and 6kWh/m(3) with recovery of 80% for NF and 40% for RO, respectively.</P>

Factors Affecting the Choice of Communication Strategies in Interaction of EFL College Learners

Park, Eunkyung,Uhm, Chul Joo 한국중앙영어영문학회 2014 영어영문학연구 Vol.56 No.2

Effective communication strategies (CSs) has been shown to enhance L2 learners’ proficiency by a number of researchers. This study investigated Korean college EFL learners’ interactions to see what factors encourage the learners to use effective communication strategies in interpersonal communications. For this, the interpersonal interactions of six pairs, two high-high proficiency pairs (H-H), two high-low proficiency pairs (H-L), and two low-low proficiency pairs (L-L), were recorded twice and analyzed for the amount of token and CSs and choice of CSs. Interviews, observations, and personal backgrounds were also collected for this qualitative study. The results showed that interactional moves have more powerful influence on the use and choice of CSs rather than learners’ proficiency. The learner’s role in the interaction, the proficiency gap with the interlocutor, and collaborative relation appeared as strong factors that affect the amount of output and choice of effective strategies.

An experimental study on the production of the double accusative ditransitives in Korean

Park, Sanghee,Yi, Eunkyung 미래영어영문학회 2021 영어영문학 Vol.26 No.4

The purpose of this study is to revisit the production of the Korean ditransitive constructions reported in Park & Yi (2021). The phenomenon is puzzling particularly because the double accusative ditransitive construction tends to be judged highly unacceptable and rarely observed in natural language corpora, while speakers produced a non-trivial number of them in an experimental setting. This study attempts to replicate the results of their production experiment on a different pool of participants and with a much larger sample size (N=96). Based on this new dataset, we conduct quantitative and qualitative analysis of speakers’ free continuations after two types of prompts, i.e., including either dative- or accusative-marked animate argument as a potential recipient. We examine the validity of the previous results and also discuss a variety of continuations provided by participants and their implications for Korean sentence production.

Hypoxia Inducible Factor-1α Directly Regulates Nuclear Clusterin Transcription by Interacting with Hypoxia Response Elements in the Clusterin Promoter

Park, Jeongsook,Park, So Yun,Shin, Eunkyung,Lee, Sun Hee,Kim, Yoon Sook,Lee, Dong Hoon,Roh, Gu Seob,Kim, Hyun Joon,Kang, Sang Soo,Cho, Gyeong Jae,Jeong, Bo-Young,Kim, Hwajin,Choi, Wan Sung Korean Society for Molecular and Cellular Biology 2014 Molecules and cells Vol.37 No.2

Differential transcription of the clusterin (CLU) gene yields two CLU isoforms, a nuclear form (nCLU) and a secretory form (sCLU), which play crucial roles in prostate tumorigenesis. Pro-apoptotic nCLU and anti-apoptotic sCLU have opposite effects and are differentially expressed in normal and cancer cells; however, their regulatory mechanisms at the transcriptional level are not yet known. Here, we examined the transcriptional regulation of nCLU in response to hypoxia. We identified three putative hypoxia response elements (HREs) in the human CLU promoter between positions -806 and +51 bp. Using a luciferase reporter, electrophoretic gel mobility shift, and chromatin immunoprecipitation assays, we further showed that hypoxia-inducible factor-$1{\alpha}$ (HIF-$1{\alpha}$) bound directly to these sites and activated transcription. Exposure to the hypoxia-mimetic compound $CoCl_2$, incubation under 1% $O_2$ conditions, or overexpression of HIF-$1{\alpha}$ enhanced nCLU expression and induced apoptosis in human prostate cancer PC3M cells. However, LNCaP prostate cancer cells were resistant to hypoxia-induced cell death. Methylation-specific PCR analysis revealed that the CLU promoter in PC3M cells was not methylated; in contrast, the CLU promoter in LNCap cells was methylated. Co-treatment of LNCaP cells with $CoCl_2$ and a demethylating agent promoted apoptotic cell death through the induction of nCLU. We conclude that nCLU expression is regulated by direct binding of HIF-$1{\alpha}$ to HRE sites and is epigenetically controlled by methylation of its promoter region.

중년 성인의 사회심리적 스트레스와 신체활동 유형과의 연관성: 지역사회 기반의 코호트 연구

Park DooYong,Park Jae-Young,Kim EunKyung,Kim YeonSoo 대한스포츠의학회 2023 대한스포츠의학회지 Vol.41 No.3

Purpose: The purpose of this study was to identify the associations between type of moderate-vigorous physical activities (MVPA) and psychological stress in South Korean, based on the Korean Genome and Epidemiology Study. The subjects of this study were 2,891 Korean men and women aged 40 to 69, who completed health examination from 2011 to 2012. M ethods: The type of MVPA was measured by using self-reported physical activity questionnaire. A high psychological stress was determined by scoring Psychological Well-being Index Short Form (≥27). Logistic regression analysis, adjusting other confounding factors, was conducted to identify the association of type of MVPA level with psychological stress (p<0.05). Results: Participants who leisure-related MVPA of ≥150 min/week was less likely have to high psychological stress than <150 min/week (odds ratio [OR], 0.72; 95% confidence interval [CI], 0.57–0.92). From the analysis of gender, leisure-related (OR, 0.50; 95% CI, 0.35–0.72) and work-related (OR, 0.63; 95% CI, 0.41–0.97) MVPA of ≥150 min/week were associated with low psychological stress in men, but women was not significantly associated. From the analysis of age, leisure-related MVPA of ≥150 min/week were associated with low psychological stress in middle age group (OR, 0.70; 95% CI, 0.53–0.92), but elderly group was not significantly associated. Differences in psychological stress OR according to type of MVPA time were observed about classification of occupations. Conclusion: High level of leisure related physical activity were independently associated with reducing risk for psychological stress. Also, encouraged MVPA by gender, age, classification of occupations could help to improve psychological stress levels in middle-aged or older adults.

Increased Brainstem Serotonergic Transporter Availability in Adult Migraineurs: an [¹⁸F]FP-CIT PET Imaging Pilot Study

Park, Eunkyung,Hwang, Yu Mi,Chu, Min Kyung,Jung, Ki-Young The Korea Society of Nuclear Medicine 2016 핵의학 분자영상 Vol.50 No.1

Purpose Recent studies have proposed central serotonergic dysfunction as a major pathophysiology of migraine. We investigated serotonin transporter (SERT) availability in migraineurs using F-18-N-(3-fluoropropyl)-$2{\beta}$-carbomethoxy-$3{\beta}$-(4-iodophenyl) nortropane ($[^{18}F]FP-CIT$) positron emission tomography (PET). Methods Brain $[^{18}F]FP-CIT$ PET images were obtained in eight women with migraine during headache free phase and 12 healthy adult women, 120 min after injection of 185 MBq. Non-displaceable binding potential ($BP_{ND}$) of $[^{18}F]FP-CIT$, which is an estimate of SERT availability, was calculated at the brainstem and compared with clinical parameters. Results $BP_{ND}$ at the brainstem was significantly higher in adult migraineurs (n=6, $1.15{\pm}0.17$) than healthy subjects ($0.95{\pm}0.14$) (p=0.04). Healthy subjects demonstrated negative correlation between brainstem $BP_{ND}$ and age (r=-0.64, p=0.02), whereas this age-related decline pattern was not found in the migraineurs. Severity of migraine attack was significantly correlated with brainstem $BP_{ND}$ (r=0.66, p=0.02), when age and duration of illness were corrected. Conclusions Increased SERT availability in the brainstem of adult migraineurs indicates low serotonin neurotransmission during headache-free phase. Patients who experience more painful headaches have lower serotonin neurotransmission. $[^{18}F]FP-CIT$ PET is a useful in vivo imaging technique for evaluating brainstem SERT availability in migraineurs.

ON THE PERIPHERY OF GORYEO BUDDHIST PAINTING: PRELIMINARY STUDY OF THE SILK WEAVE, WIDTH OF THE SILK AND ENSHRINEMENT OF WORKS

( Park Eunkyung ) 국립중앙박물관 2010 Journal of Korean Art and Archaeology (JKAA) Vol.4 No.0

Matters of style and iconography, patrons and donors are key issues in the study of Goryeo Buddhist painting. But in this paper I would like to talk about some of the issues on the peripheries, examining three aspects in particular that have always interested me: the weave of the silk used for the paintings, the width of the woven silk, and the enshrinement of the finished work. First, it has been confirmed that all of the 160-odd Goryeo Buddhist paintings known to be extant were painted on silk. In almost all cases, the silk fabric is woven in plain weave, with a space after every two warp threads.1 Compared to ordinary plain weave, which has evenly spaced warp threads, this rib weave enables greater expression of depth and texture when colors are applied on the front or the back of the silk. Second, most Goryeo Buddhist paintings are painted on a single width of silk. This gives rise to several questions, such as “What does this imply in terms of the width of the silk, and what impact did it have on the composition of the painting?” Collating the figures on silk widths revealed that they varied in size from around 40cm wide to extra large widths up to 250cm wide. According to the widths the paintings could be divided into five groups, A-D and E for special cases. Analysis of these groups indicated that the iconography and composition of Goryeo Buddhist paintings were influenced by the size of the woven silk, and that pointed to the possibility that the court office called Aekjeongguk ( ) was involved in the production of the larger works falling under groups C, D, and E. Last, it is impossible not to be curious about the system of enshrinement of Goryeo Buddhist paintings. As is well known, relics were enshrined with the sculptures of Buddhas and Bodhisattvas. In this light, did a similar system of enshrining votive offerings exist for paintings? It is believed that Buddhist paintings were generally commissioned by the royal family or members of the ruling class to hang in private shrines, but do we have any concrete knowledge of where the paintings were really enshrined? Taking the example of the painting of Amitabha preserved at Shōbōji in Kyoto, which first suggested the idea that votive offerings were made with paintings, the issue of the enshrining of votive offerings and the way they would have been enshrined was examined. In addition, examination of documents from the 13th and 14th centuries revealed that Goryeo Buddhist paintings were enshrined in various places such as Buddhist halls on palace grounds, royal shrines, shrines big and small near the homes or ancestral graveyards of powerful families and officials of the ruling class, built to pray for the repose of the dead or pray for blessings, temple halls, and private shrines in the homes of officials. Special cases include Mangwondang ( ), a Goryeo royal residence in Yuan. The places of enshrinement were studied in connection with the size of paintings.

Study on Policy Study of Gyeonggi Provincial Office of Education: A Case Study of Development and Application of School Physical Education Curriculum Based on Lesson Contents Selection Right of Students

( Eunkyung Park ),( Taekoo Lee ) 한국체육학회 2016 국제스포츠과학 학술대회 Vol.2016 No.1

Purpose: This study has the objective (1) to develop the school Physical Education (PE) curriculum based on lesson contents selection right of students, and (2) examine the responses of students and teachers. Researchers related with intrinsic motivation theory assert lesson strategies based on selection of students in school learning enhance education participation motive and responsibility of students. Method: Participants were 897 students (male:433, female:464) and 43 teachers (male:8, female: 35) in the middle school. Data were collected using open-ended questionnaire and in-depth interviews with students and teachers. Qualitative data were analyzed using inductive content analysis. Result: The results of this study were (1) the school PE curriculum based on lesson contents selection right of students was developed. It consisted of PE lessons and school sports clubs activity containing basketball, dance, soccer, badminton, table tennis, PAPS and convergence instruction based on the results of student survey and consultation with teachers in the beginning of 1^st semester. PE teachers arranged for it and met their class during a year. And sports instructors were hired and the investment of a great deal of equipment and budget was supported to act up to it. And (2) students responded that the school PE curriculum was: (a) joyful and pleasant, (b) effective of improvement of physical fitness and motor skills (c) promoting social relationship positively (d) was good for situations of lesson, and teachers responded that was: (a) giving them satisfaction (b) reducing their workload (c) influencing school climate and the operation of the school curriculum affirmatively. Conclusion: Firstly, the school PE curriculum based on lesson contents selection right of students enhance education participation motive and responsibility of students. So, students were satisfied with it and enjoyed. Secondly, the problem of decline in quality of school sports clubs activity on operation researchers have pointed out got solved. At the same time teachers’ satisfaction of it combined PE lesson with sports club activity improved. Thirdly, a great deal of equipment and budget went into it to carry out it. So the investment of equipment and budget is the necessary condition to carry out it based on lesson contents selection right of students successfully.