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>

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.

육총용류의 면역증진 효과 비교 연구

오정석,함인혜,김형민,최호영 대한본초학회 2005 大韓本草學會誌 Vol.20 No.1

Objectives : This study was to investigate the anti-immobility effect of Cistanche deserticolae Herba (CD) and Cistanche salsae Herba (CS) Methods : Forced swimming test (FST) and changes of blood biochemical parameters related to fatigue, glucose (Glc), blood urea nitrogen (BUN), latic dehydrogenase (LDH) aspartate aminotransferase (AST), alanine aminotransferase (ALT) and total protein (TP) were investigated. Results : CD and CS were orally administered to mice for 7 days. After 7 days, the immobility time was significantly decreased in the CD-treated group and CS-treated group in comparison with the control group. The contents of serum AST were significantly decreased and contents of Glc and LDH were decreased in CD-administration group . However, it had no effect on the elevation of TP level, whereas, the contents of GIc were increased and the contents of ALT, BUN and LDH in the blood serum were decreased in the CS (0.01 g/kg/day)-fed group. Conclusions : These results suggest that Cistanche herba, CD and CS may have immune-enhancing effect.

Hand & rotary root canal instrument의 근관내 삭제 형태에 관한 전자현미경적 비교

오태석,박정원 大韓齒科保存學會 1998 Restorative Dentistry & Endodontics Vol.23 No.1

In the case of CAD/CAM ceramic inlay restorations, if isthmus width is widened too much, it may cause fracture of remaining tooth structure or loss of bonding at the luting interface because of excessive displacement of buccal of lingual cusps under occlusal loads. So to clarify the criterior of widening isthmus width, this study was designed to test the tensile bond strength and bond failure mode between dentin and ceramic cemented with luting composite resin cements. Cylindrical ceramic blocks(Vita Cerec Mark Ⅱ, d=4mn) were bonded to buccal dentin of 40 freshly extracted third molars with 4 luting composite resin cements(group1:Scotchbond Resin Cement/Scotchbond Multi-Purpose, group2:Duolink Resin Cement/All-Bond 2, group3:Bistite Resin Cement/Ceramics Primer, and group4:Superbond C&B). Tensile bond test was dond under universal testing machind using bonding and muasuring alignment blocks(￠ilo & Um, 1992). After immersion of fractured samples into 1% methylene blue for 24 fours, failure mode was analysed under stereomicroscope and SEM. Results:The tensile bond strength of goup 1, 2 & 4 was 13.97±2.90 MPa, 16.49±3.90 MPa and 16.17±4.32 MPa. respectively. There was no statistical differences(p>0.05). But, group 3 showed significantly lower bond strengnth(5.98±1.17 MPa, p<0.05). In almost all samples, adhesive fractures between dentin and resin ccments were observed. But, in group 1, 2 & 4 as bond strength increased, cohesive fracture within resincement was observed simultaneously. And, in group 3, as bond strength decreased, cohesive fracture between hybrid layer and composite resin cement was also observed. Cohesive fracture within dentin and porcelain adhesive fracture were not observed. In conclusion, although adhesive cements were used in CAD/CAM fabricated ceramic inlay restorations, the conservative priciples of cavity preparation must be obligated.

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 앎과 체육교육의 방향

오정석 師範大學 體育硏究所 1995 서울大學校 體育硏究所論集 Vol.16 No.2

The objective of this study is to illuminate the value of physically derived knowledge in physical Education and the orientation of physical Education. In the pursuit of the above research objective the following things were examined. A) An attempt was made to clarify physically derived knowledge; under the premise that it should be centered as the unique domain of physical education was examined. B) While re-interpreting the concept of physical education based of the premise of physically derived knowledge, the essential value of physical education was examined. C) The ideal course of development of physical education in relation to the mode of physically derived knowledge and the human originality and reallegation inherent in this were examined. Ultimately, through a re-evaluation 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 education of human existence.

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.