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.

통풍형 방음벽 개발 및 적용에 관한 연구

윤제원(Je-Won Yoon),김영찬(Young-Chan Kim),김금모(Keum-Mo Kim),장강석(Kang-Seok Jang),구본성(Bon-Sung Ku),엄주용(Joo-Yong Eom) 한국소음진동공학회 2011 한국소음진동공학회 학술대회논문집 Vol.2011 No.10

The purpose of this study is to develop an air-passing soundproofing panel with more improved structure to reduce the CO2 emission and installation cost. To reduce the emission of CO2 ; it is suggested to choose low CO2 emission material relative to the aluminum and to reduce the materials by developing a specially designed air-passing soundproofing panel structure. First of all, we performed the flow analysis to predict the wind pressure according to the open angle of the air-passing soundproofing panel and the noise level analysis at the receiver point. To verify the simulation, a prototype of the soundproofing panel was made. The flow test in the wind tunnel and load test were performed. The economic evaluation for the installation of the air-passing soundproofing panel was performed and specifications of the installation was prepared. As the results of this research, it was verified that the wind load was reduced about 40% to that of the conventional one at 25m/s wind speed in the wind tunnel test. By applying the 4m span soundproofing wall with air-passing soundproofing panel and under the cost of 250 thousand won/m2 instead of the conventional 2m span panel, the installation cost will always be lowered than the conventional one in the combination of (60:40~50:50) conventional to air-passing soundproofing panel from the economic evaluation. The 20% reduction of CO2 was found by changing the 50% of aluminum soundproof panel to air-passing soundproofing panel.

제주물을 이용한 기능성 및 혼합음료의 개발방향 설정에 관한 연구

고성보(Ko, Seong-Bo),현창석(Hyun, Chang-Seok),강경원(Kang, Kyung-Won) 한국산학기술학회 2011 한국산학기술학회논문지 Vol.12 No.5

세계적으로 건강기능식품의 주변 환경은 매우 빠르게 변하고 있다. 2012년 세계기능성 음료시장은 269억달 러 규모, 아태지역 시장은 136억달러 규모가 될 것으로 전망하고 있다. 국내 먹는 샘물 시장은 2008년 4,400억원 규 모를 형성하고 있고, 제주삼다수의 매출액은 891억원이다. 그러나 “제주삼다수”라는 브랜드는 한계성을 지니고 있다. 이에 대한 방안으로 제주물의 품질 우수성을 알리는 포괄적인 광고가 필요하며, 제주 물을 이용한 기능성 음료 및 혼 합음료 개발의 성공 가능성을 높이기 위해서 제주워터(Jeju Water)라는 글로벌 통합브랜드 개발이 필요하다. 기능성 및 혼합음료 제품개발시 제주지역의 농산물의 기능성을 적극 활용해 물산업과 제주의 1차산업을 연계해 농산물의 과 잉생산 처리와 고부가가치화를 촉진시킬 필요가 있다. The environment of the health food in the world has been changed very rapidly. The world market volume of functional drinks in 2012 will be estimated at $ 26.9 billion, and Asia-Pacific market is expected to be $ 13.6 billion. The domestic market volume of bottled water in 2008 was 440 billion won, and "Jeju Samdasu" sales was 89.1 billion won. But the brand of "Jeju Samdasu" has the limits. As a solution, the comprehensive advertising of the excellence quality of Jeju water is required. To increase the likelihood of success in development of functional and mixed drinks by the water is necessary to develop a global integrated brand. In developing the functional and mixed drinks by the water, we apply the functionality of the Jeju agricultural products actively, and connect Jeju Water industry with Jeju agricultural industry, which promote the overproduction control and the high value- added agricultural products.

Sequential Changes in Aberrant Crypt Foci and Lectin Expression in the Early and Late Stages of DMH-Induced Colon Carcinogenesis in Rats

Won, Hye Sung,Maeng, Lee So,Chae, Hiun Suk,Kim, Hyung Keun,Cho, Young Suk,Kang, Jin-Hyoung,Jang, Hong Seok,Ryu, Mi-Ryeong The Korean Society of Gastroenterology; the Korean 2012 Gut and Liver Vol.6 No.2

<P><B>Background/Aims</B></P><P>The purpose of this study was to investigate the malignant potential of aberrant crypt foci (ACF) by measuring the multiplicity of crypts and lectin expression in the early and late stages of 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis.</P><P><B>Methods</B></P><P>Six-week-old Wistar rats were injected subcutaneously with DMH for 27 weeks. We classified ACF according to the number of crypts per ACF as a few crypts (≤3 crypts, FC ACF) or numerous crypts (≥4 crypts, NC ACF). Immunohistochemistry was used to evaluate lectin expression.</P><P><B>Results</B></P><P>In the early stage, FC ACF (590/1,902, 31.0%) occurred more frequently than NC ACF (35/449, 7.8%); whereas in the late stage, NC ACF (176/449, 39.2%) occurred more frequently than FC ACF (324/1,902, 17.0%). The number of ACF peaked at 15 to 20 weeks. The ratio of NC/FC ACF increased gradually during carcinogenesis. The expression of both UEA1 and PNA was higher in NC ACF than FC ACF. Lectin expression increased in the late stage compared with the early stage.</P><P><B>Conclusions</B></P><P>The expression of lectin was higher in NC ACF and ACF in the late stage. Therefore, ACF with higher multiplicities in the late stage may have more malignant potential in DMH-induced colon carcinogenesis.</P>

Vacuum-controlled wafer-level packaging for micromechanical devices

Kang, Seok Jin,Moon, Young Soon,Son, Won Ho,Choi, Sie Young IOP Publishing 2014 Japanese journal of applied physics Vol.53 No.6

Drying-mediated Assembly of DNA Strands into Large Area Patterned Arrays

Seok Hee KANG,Young Woo KWON,Suck Won HONG 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

Magnetic Resonant Wireless Power Transfer with Rearranged Configurations

Seok Hyon Kang,Chang Won Jung 한국전자파학회JEES 2017 Journal of Electromagnetic Engineering and Science Vol.17 No.2

We investigate the indirect-fed magnetic resonant wireless power transfer (MR-WPT) system for wireless charging for mobile devices by rearranging the loops and coils. Conventional MR-WPT is difficult to apply to consumer electronic products because of the arrangement of the resonators. In addition, there are restrictions for charging using a wireless technology, which depend on the circumstances of the usage scenarios. For practical applications, we analyzed the transfer efficiency of the MR-WPT system with various combinations and positions of resonators. Three rearranged configurations (Out-Out, Out-In, In-In) have been considered and experimentally investigated using hollow pipe loops and wire copper coils. There were four types of loops and two types of coils; each one had a different diameter and thickness. The results of the measurements show that the trends of the transfer efficiencies for the three configurations were similar. A transfer efficiency of 82.5% was achieved at a 35-cm distance between the 60-cm diameter transmitter (Tx) and receiver (Rx) coils.

The Influence of Organizational Justice on Employees' Motivation to Participate in Training: A Quality System Perspective on Human Resource Practices

Kang, Dae-Seok,Kim, Youn-Sung,Lee, Dong-Won The Korean Society for Quality Management 2006 The Asian Journal on Quality Vol.7 No.1

This study sought to examine the effect of three (distributive, procedural, and interactional) justice perceptions in predicting employees' motivation to participate in training activities. On the basis of theoretical linkages between the constructs, full mediation and partial mediation models by perceived benefits of training were developed. The models were tested using SEM (Structural Equation Modeling) on responses from 302 employees of three wireless operators in the Republic of Korea. The results showed the partial-mediation model is a dominant model. It also confirmed that interactional justice directly influence motivation to participate in training, whereas procedural justice influence the variable through perceived benefits of training. Furthermore, limitations and implications of the current study and directions for future work are discussed.

Effect of dyslipidemia on vascular smooth muscle cell proliferation in a porcine coronary restenosis model

Kang Jin Jeong,Philyong Kang,Hwal-Yong Lee,Hee Chang Son,Sung Hyun Park,Won Seok Choi,Bon Sang Koo,Chang-Yeop Jeon,Seug Ho Baek,You Jung An,Hyun Kuk Kim,Sung Soo Kim,Jun Kyu Park,In Ho Bae,Dae Sung Pa 충북대학교 동물의학연구소 2019 Journal of Biomedical and Translational Research Vol.20 No.4

Best estimate calculation and uncertainty quantification of sodium-cooled fast reactor using MARS-LMR code

Kang, Seok-Ju,Jeong, Hae-Yong,Bae, Sung-Won,Choi, Chi-Woong,Ha, Kwi-Seok,Suh, Jae-Seung Elsevier 2018 Annals of nuclear energy Vol.115 No.-

<P><B>Abstract</B></P> <P>The safety analysis of nuclear power plants has been performed using conservative approach based on conservative assumptions and boundary conditions to evaluate the safety margin of plant operation. However, this conservative approach could lead to unrealistic behavior predictions and eventually distort some phenomena in reactor systems. Therefore, the nuclear field moved towards an alternative best-estimate approach with uncertainty quantification in order to improve the phenomena prediction and to decrease the excessive conservatism in safety margins. In this study, the best estimate methodology is applied to improve the accuracy and reliability in safety analysis of an SFR. The applied best estimate methodology is based on the CSAU. This methodology is composed of three unique steps for evaluation of code capability, assessment and range of parameters, and sensitivity and uncertainty analysis. The primary purpose of this study is to evaluate the appropriateness of sensitivity parameters and its ranges, which have been determined through intensive experts’ panel discussion, by use of the data obtained from the EBR-II Unprotected Loss of Flow (ULOF) experiment. The MARS-LMR thermal–hydraulic code and the parallel computing platform integrated for uncertainty and sensitivity analysis (PAPIRUS) become the basic calculation tools in the study. Confirmation of data coverage is performed through the evaluation of coolant temperature in the instrumented subassemblies XX09. The appropriateness of parameters and its ranges are evaluated for three different cases: original parameters and ranges suggested in the MIRT, ±10% increased parameter ranges, and 200% increased axial reactivity feedback coefficient only. The case with the original parameters and ranges does not result in a valid data coverage, which means inadequate modeling accuracy for the ULOF scenario. The other two cases give complete coverage of EBR-II temperature data measured at the core top, which suggest the need of further refinement of reactivity models. The relative importance of the parameters is confirmed through the sensitivity analysis with respect to the Figures of Merit (FoM). The selected dominant parameters are the sodium density reactivity, above core load pad strain coefficient, core radial expansion reactivity coefficient and fuel axial expansion reactivity coefficient. The pump coastdown curve and the core inlet form loss are also found to be significant parameters during the transient.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A best-estimate approach based on the CSAU is applied to the ULOF analysis of a pool-type SFR. </LI> <LI> The MARS-LMR code and the PAPIRUS tool are used to perform the uncertainty and sensitivity analyses. </LI> <LI> The sensitivity parameters and its ranges are determined through intensive experts’ panel discussion. </LI> <LI> The data coverage of code models is validated with the coolant temperature measured in EBR-II test. </LI> <LI> The relative importance of parameters is evaluated with the sensitivity study for the FoMs. </LI> </UL> </P>