Superconducting MgB2 Wire Drawing Considering Anisotropic Hardening Behavior and Hydrostatic Effect

Young‑Seok Oh,Ho Won Lee,Kook‑Chae Chung,Duck‑Young Hwang,Seong‑Hoon Kang,Jeong Whan Yoon 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

Numerical modeling was conducted to investigate the deformation behavior of powder mixture during multi-pass drawingprocesses for multi-filamentary MgB2wire. A modified Drucker-Prager Cap (DPC) model with an elliptical cap surface usingthe new material characterization method was developed to capture the anisotropic hardening behavior and hydrostatic effectof the powder mixture. A number of uniaxial die compaction, cold isostatic pressing, diametrical compression, and uniaxialcompression tests were conducted using different powder densities to characterize the modified DPC model. A commercialfinite element software ABAQUS with a user subroutine was used to simulate the drawing of the MgB2wire. The densityand area fraction of the powder mixture during the wire-drawing process were verified with experimental results. The differencein packing density at the inner and outer filaments of the MgB2wire was successfully captured by simulation. Inaddition, the effect of the initial packing density on the superconducting properties of MgB2wire was numerically studied. It is shown that the increase in the superconducting area, which results from a high initial packing density, should be moreeffective compared to the increase in the grain connectivity in enhancing the critical current properties for the MgB2wirewhen the final packing density is saturated after a number of drawing processes.

Species and habitat-dependent accumulation and biomagnification of brominated flame retardants and PBDE metabolites

Choo, Gyojin,Lee, In-Seok,Oh, Jeong-Eun Elsevier 2019 Journal of hazardous materials Vol.371 No.-

<P><B>Abstract</B></P> <P>The occurrence, species- and habitat-dependent distribution of brominated flame retardants (BFRs) and PBDE metabolites comprising 27 polybrominated diphenyl ethers (PBDEs), 3 hexabromocyclododecanes (HBCDs), tetrabromobisphenol A (TBBPA), 17 methoxylated (MeO-) BDEs, and 8 hydroxylated (OH-) BDEs were determined in marine environments (sediment and seawater) and 20 biota species in food web in the southern part of Korea. The concentration of HBCDs was statistically higher in both pelagic (5.73–60.1 ng/g lipid weight [lw]) and demersal fish (2.45–31.3 ng/g lw), whereas a higher level of OH-BDEs was observed in benthic invertebrates (2.48–40.7 ng/g lw), suggesting different composition of BFRs and PBDE metabolites between species. The concentrations of TBBPA and MeO-BDEs were significantly higher in pelagic fish (1.31–11.3, 6.15–61.5 ng/g lw) than in demersal fish (not detected [N.D.]–4.45, 0.956–8.52 ng/g lw) and benthic invertebrates (N.D.–8.11, 0.182–4.65 ng/g lw), reflecting a dependence on habitat. Additionally, analogue distribution of PBDEs in pelagic fish was similar to that in seawater, whereas the distribution in demersal fish and benthic invertebrates was similar to the distribution in sediment. The bioconcentration factor (BCF) and trophic magnification factor (TMF) of α-HBCD, some of PBDEs, and 6-MeO-BDE47 were up to 5000 and 1, respectively, suggesting strong bioaccumulation and biomagnification.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Different distributions of BFRs and PBDE metabolites were observed according to the species and habitat of biota. </LI> <LI> The level of HBCDs was higher in pelagic and demersal fish, whereas OH-BDE level was higher in benthic invertebrates. </LI> <LI> The concentrations of MeO-BDEs and TBBPA in pelagic fish were higher than those in demersal fish and benthic invertebrates. </LI> <LI> α-HBCD, some congeners of PBDEs (BDE49, 71, 100), and 6-MeO-BDE47 were strongly biomagnified and bioaccumulated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

PBDEs and their structural analogues in marine environments: Fate and expected formation mechanisms compared with diverse environments

Choo, Gyojin,Kim, Da-Hye,Kim, Un-Jung,Lee, In-Seok,Oh, Jeong-Eun Elsevier 2018 Journal of hazardous materials Vol.343 No.-

<P><B>Abstract</B></P> <P>The concentrations and relative distributions of 27 polybrominated diphenyl ethers (PBDEs) and 17 methoxylated (MeO-) and 8 hydroxylated (OH-) BDEs were determined in marine environments including sediments, bivalves, and seawater along the southern coast of South Korea to understand their fates and possible formation mechanisms. The relative and substituent distributions of the PBDEs and their structural analogues varied according to the characteristics of the media. PBDEs were dominant in marine sediments and seawater, whereas MeO-BDEs made the highest contributions in bivalves. Similar patterns were previously identified in inland environments in Korea, except in river water where OH-BDEs were dominant. The natural formation of structural analogues might be the main mechanism in marine, as <I>ortho</I>-substituted naturally occurring MeO- and OH-BDEs were dominant in all media and seemed to be more produced than in inland environments. In addition, the higher concentrations of meta-substituted MeO-BDEs nearshore than offshore was observed. This is the first study comparing marine (near- and offshore) and inland to understand the differences in their fate and possible formation mechanisms in each environmental conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The distributions of PBDEs and their structural analogues were compared between marine (near- and offshore) and inland. </LI> <LI> PBDEs dominated in abiotic media, whereas MeO-BDEs were dominant in biota. </LI> <LI> Natural formation might be the main mechanism for PBDE structural analogues in marine and was highly occurred than in inland. </LI> <LI> The higher contributions of meta-MeO-BDEs were observed in inland and nearshore than offshore. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

서울 지역 여자대학교 집단에서 월경전기 증후군 및 월경전 불쾌기분장애의 유병율

정범석,이철,이지현,서민경,한오수,김창윤 大韓神經精神醫學會 2001 신경정신의학 Vol.40 No.4

연구목적 : 가임기 여성의 75%가 하나 이상의 월경전기 증상을 경험하며, 일상생활에 지장을 주는 경우도 3∼8%에 이르지만 한국 여성을 대상으로 한 월경전기 증후군(Premenstrual syndrome : PMS)및 월경전 불쾌기분장애((Premenstrual dysphoric disorder : PMDD)에 대한 역학 조사는 부족한 실정이다. 따라서 본 자들은 한국에서의 유병율, 증상의 양태 및 삶에 미치는 정도 등의 역학 조사를 통해 월경전 불쾌기분장애에 대한 올바른 정보를 제공하고 관련 임상 연구의 기초자료로 활용하고자 본 연구르 시행하였다. 방 법 : 6개의 서울 소재 4년제 여자대학교에서 무작위 군집표본 추출로 선택된 4개 학교의1∼3학년 학생 중 무작위 군집표본추출을 통해 선택된 1419명을 대상으로 하였다. DSM-IV진단기준을 근거로 저자들이 제작한 6점 척도의 설문지가 사용되었으며, 난포기에 비해 황체기에 75%이상 악화된 경우 증상이 있다고 판정할 경우의 월경전 불쾌기분장애의 유병율을 조사하였다. 월경전 불쾌기분장애 집단과 증상은 있으나 진단기준에 부합되지 않는 월경전기 증후군 집단으로 나누어 증상 양태, 식습관 변화, 생활에 미치는 영향 정도 등을 비교하였다. 결 과 : 부적절한 자료 198명(13.9%), 주요 신체 혹은 정신질환을 앓은 경우 등 선정 배제 기준에 속하는 경우 348명(24.5%)을 제외한 873명이 최종 분석되었다. 873명 중 월경전 불쾌기분장애의 유병율은 5.0%이었으며, 월경전기 증후군의 유병율은 83.3%이었다. 가장 흔한 증상은 월경전기 증후군 집단의 경우 신체증상(54.6%)이었고, 월경전 불쾌기분장애 집단의 경우 '지속적으로 짜증난다'(95.5%)이었다. 월경전 불쾌기분장애 집단의 88.6%에서 증상 때문에 한 달에 1∼2회 이상 일이나 공부에 지장이 초래되었다. 결 론 : 한국 여자대학생 집단이 경험하는 월경전 불쾌기분장애의 유병율과 증상 양상은 외국과 비슷하다. 아울러 월경전 불쾌기분장애 집단은 월경전기 증후군 집단에 비해 기분 증상이 더 흔하고 심하는 점에서 월경전 불쾌기분장애는 월경전기 증후권과 구별되는 하나의 질환 상태임을 시사한다. Objects : More than 75% of women have been reported to experience premenstrual symptoms and three to eight percent of them suffer from premenstrual dysphoric disorder(PMDD). But little is known about prevalence of premenstrual syndrome(PMS) and PMDD and PMS in Korean women who sttended universities at the time of survey. Methods : One thousand four hundred and nineteen subjects were randomly selected with cluster sampling methods among four women's university in Seoul. We measured the severity of premenstrual symptoms using six-point rating scale developed by the authors on the basis of the research criteria for PMDD in DSM-IV. Premenstrual worsening of symptoms was defined as increase in symptom scores of more than 75% from follicular to luteal phase score. And also, we compared characteristic symptoms, eating behaviors, and functional impairments between PMS and PMDD. Results : After excluding inadequate data according to our exclusion criteria, 873 of 1419 subjects(61.5%) were included in the estimation of the prevalence of PMS and PMDD. Each prevalence rate of PMS and PMDD was found to be 83.3% and 5.0% on the basis of 75% change method respectively. The most frequent symptom was physical symptoms such as headache or breast tenderness(56.4%) in PMS and 'felt irritable'(9.5%) in PMDD. Of the 44 subjects with PMDD, 39(88.6%) reported to have experienced the impairment in work or school at least once per month because of premenstrual symptoms. Conclusions : Our results indicate that prevalence and symptoms of PMDD in Korean university women are similar to those in western culture. The finding that mood symptoms were more frequent and severe in PMDD than in PMS implies that the former may be a disordered condition to be distinguished from the latter physiologic one.

Estrogen이 가토의 이개변형에 미치는 영향

오경,김정희,김정태,김석권 大韓成形外科學會 1999 Archives of Plastic Surgery Vol.26 No.1

Congenital auricular deformities such as lop ear, cup ear, prominent ear, and Stahl's ear can be corrected nonsurgically in the early neonatal period(first week after birth) obtaining satisfactory results. Auricular cartilage consists of chondrocytes and intercellular materials that are mainly assembled from collagen, elastin, and a proteoglycan aggergate. Cartilageelasticity is dependent upon the concentration of the proteoglycan aggregate. Hyaluronic acid, which is a constituent of proteoglycan aggregate and is increased by estrogens, has an important play on disconnecting the proteoglycan aggregate. So the increased estrogen results in the lack of elasticity. The circulating levels of free estradiol are higher during the first 72 hours after birth and decreases thereafter, so the ear is soft and easily malleable in this early neonatal period. In this study, we have applied aluminium splint(90 degree-angulated, 180 degree-angulated, and rolled) on rabbit ear. All of the rabbit was divided into 3 groups containing 3 types of deformities. In group 1, estrogen was applied to the deformed ear with regional injection to the perichondrium of auricular cartilage. In group 2. estrogen was applied topically with ointment. In group 3, as control group, saline was injected to the perichondrium. Four weeks later, in group 2, the shape of the deformed rabbit ear was maintained, and did not return to its original shape even after splint removal. From these results, we concluded that estrogen ointment could be tried as adjunctive therapeutic modalities to the nonsurgical treatment of the congenital auricular deformities.

면접조사를 통한 초등학생의 영양교육 실태 및 실천도 조사

오유진,이영미,김정현,안홍석,김정원,박혜련,서정숙,김경원,권오란,박혜경,이은주,성현이 대한지역사회영양학회 2008 대한지역사회영양학회지 Vol.13 No.4

This study investigated the experience and practice of elementary school students on nutrition education. The data were collected from 217 male and female students attending 5-6th grade elementary schools in Seoul and Kyunggi-Do from March to June 2007, interviewing face to face by a nutrition teacher and 3 interns of a nutrition teacher. The results were as follows: 86.5% of the subjects learned about ‘Table etiquette’, ‘Reasons for eating fruits and vegetables’ (78.7%), ‘Food waste and environment’ (72.3%), ‘Healthy snacks’ (55.7%), ‘Food sanitation’ (52.3%), ‘Food culture of foreign countries’ (48.1%). Nutrition education experience was significantly different by gender. A total of 43.5% boys responded that they never learned about ‘basic food preperation’ (p < 0.01). They had learned ‘Nutrients for body’ and ‘Food waste and environment’ in school, ‘Healthy weight loss’, ‘Food culture of foreign countries’, ‘Food circulation’ on television, Most content (‘Table etiquette’, ‘Simple cooking’, ‘Food sanitati n’, ‘Eating behaviors for health’, ‘Reasons for eating fruits and vegetables’, ‘Healthy snacks’) was learned from parents. The practice after nutrition education was higher in ‘Table etiquette’ (2.14), ‘Eating fruits and vegetables’ (2.07) than others compared with education experience. The most reason of non-practice on nutrition information was ‘Troublesome’. In ‘Nutrients for body’, a boy answered ‘Difficult for practice’ 20.0%, a girl answered ‘Difficult to understand’ 32.6%, showing a significant difference between the gender groups (p < 0.001). They remembered the ‘Nutrients for body’ (49.6%), ‘Food sanitation’ (44.5%) because of ‘important content’,‘Basic food preparation’ (40.6%), ‘Food culture of foreign countries’ (36.3%) because of ‘interesting content’, ‘Healthy weight loss’ (52.0%), ‘Eating behavior for health’ (44.5%) and ‘Healthy snacks’ (33.7%) because of ‘need for my health’.

체육적 앎의 자원 : 운동수행

오정석,김달우 師範大學 體育硏究所 1994 서울大學校 體育硏究所論集 Vol.15 No.1

The objective of this study is to illuminate the value of performance as the source of knowledge in physical Education. In the pursuit of the above research objective the following things were considered; A) The current direction being pursued in physical education was examined. B) An attempt was made to clarify ‘physically derived knowledge’, under the premise that it should be centered as the unique domain of physical education. C) While re-interpreting the concept of physical education based of the premise of ‘physically derived knowledge’ the essential value of physical education was examined. D) The ideal course of development of physical education in relation to the mode of physically derived knowledge and the human originality and realization inherent in this were examined. Ultimately, through a re-eveluation of the current state of physical education we have attempted to illuminate the estrangement of physical education from it's core concern, that is, the value derived from movement by the human being. Futhermore, an attempt was made to identify that aspect of physical education which is unique only to physical education, that is, knowledge derived from human movement or from the physical demension of human existence.

동일한 혈관 내에 발생한 이식형 약제 주입기 카테터의 위치이상

오대석,김영재,김명훈,조광래,임세훈,이정한,이근무,정순호,신치만 仁濟大學校 白病院 2010 仁濟醫學 Vol.31 No.-

저자들은 56세 여성 환자의 왼쪽 쇄골 하 정맥에 시행한 이식형 약제주입기 카테터의 삽입 후 발생한 비정상 위치에 대한 증례를 보고하고자 한다. 카테터의 끝은 환자의 늘 어진 가슴, 체위, 신체의 움직임, 카테터의 유동성 등의 영향으로 천자된 정맥 내에서 견인되고 뒤쪽으로 이동하였다. 환자는 어떠한 증상도 호소하지 않았지만 비정상 위치의 카테터는 심각한 합병증을 유발할 수 있기 때문에 제거되었다. 따라서 시술자는 약제주입기 삽입 전에 환자의 신체 상태와 단순 흉부 촬영상을 확인하고 카테터의 비정상 위치가 발생할 수 있는 위험 징후를 알아차려야 하겠다.

국가종합전자조달시스템의 이용확산과 조달행정 발전방안

오정석,이낙영 충남대학교 기초과학연구소 2003 忠南科學硏究誌 Vol.30 No.1

The Government e-Procurement System(GePS) is a comprehensive system to be established for public procurement administration usage, which permits the administration to be more effective in its work. GePS enables all public organizations to conduct the procurement process electronically, and thus makes the procurement administration much more effective and transparent. A single window containing all procurement information allows enterprises a great of convenience in their commerce activities. Additionally, the development of an electronic network means that all information related to the procurement business may be jointly used. This joint usage of information and easy document exchange between public organization and private companies reduces remarkably the amount of paperwork and documentation needed for a contract. The purpose of this paper is to find a way of expanding the usage of GePS by analyzing statistics prepared in early in its operations. The plans of political development for the Procurement administration as the operator of GePS in the time of government digitalization are presented in this paper.

CITIS 지원 문서관리 시스템 설계에 대한 연구

정석찬,조장혁,김상균,류병우,오원식,김정훈,최익성 한국경영과학회 1998 한국경영과학회 학술대회논문집 Vol.- No.1

본 연구에서는 일반 기업간에 전자상거래를 지원하기 위한 CITIS(Contractor Integrated Technical Information Service)를 지원하는 문서관리 시스템을 개발하기 위하여, MIL-STD-974의 요구사항과 일반적으로 상용화되어 있는 문서관리 시스템의 기능적 요구 사항을 검토하였다. 이것을 바탕으로 기업간 기술정보 교환의 근간이 될 수 있는 CITIS를 지원하는 문서관리 시스템의 기능을 도출하였다. 조달자인 정부와 공급자인 기업간의 계약에 의한 기술정보 서비스로서의 CITIS 요구사항을 기본으로 하되, 이를 CALS 환경에서 기술정보 서비스에 적용할 수 있도록 개발 요구 사항을 재정립하였다. 일반적인 문서관리 시스템의 기능은 현재 시장에서 상용화되어 있는 PDM 제품의 기능을 분석하여 참조하였다. 한편 CITIS 지원을 위한 부품 구조 관리 기능과 연계를 위하여 문서와 부품 간의 관계가 고려되었으며, 작업흐름관리와의 연동을 위해서는 전자 결재판 개념의 패킷 객체가 고안되었다. 소프트웨어 설계 방법론으로는 객체지향형 소프트웨어 개발 방법론을 채택하여 CITIS 구현을 위한 객체 모델, 동적 모델, 기능 모델을 작성하였다. 소프트웨어 개발 언어는 인터넷 웹 브라우저를 근간으로 활용될 수 있도록 Java를 이용하며, 다른 응용분야와의 손쉬운 통합을 위하여 CORBA 개념을 도입하였다.