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>

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.

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.

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.

Terfenadine과 Ketoconazole 병용투여에 의해 유발된 Torsade de Pointes1예

오석규,국향,임수빈,정진원,박양규,박옥규 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.3

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.

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.

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.