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.

Gilbert 증후군에서 열량 제한 시험과 Phenobarbital 자극 시험의 의의(14예)

이헌영,채경훈,정재훈,강윤세,김연수,문희석,박기오,이엄석,김선문,김석현,성재규,이병석,이강욱 충남대학교 의학연구소 2003 충남의대잡지 Vol.30 No.2

Gilbert 증후군은 인구의 7%에서까지 나타날 수 있는 매우 흔한 증후군으로서 비진행성인 양성의 만성적 경과를 치하며, 간질환의 증상과 징후가 없는 경한 비포합형 고빌리루빈혈증이 특징인 일종의 체질적인 증상으로서 혈장 빌리루빈 농도에 대한 사춘기의 영향 때문에 10대와 20대에 자주 진단이 된다. 따라서 임상적인 중요성은 미약하지만 높은 빈도가 예상되는 점에 그 중요성이 부여되어야 할 것이다. 따라서 적정한 임상적 진단법으로 기왕에 소개된 열량제한 시험과 phenobarbital 유도 시험을 시행하고 이들의 진단적 가치를 알아보기 위하여 본 연구를 시행하였다. 1990년 7월부터 1999년 4월까지 충남대학교병원에 내원하여 HBsAg, IgG anti-HBc 및 anti-HCV가 음성이고, 간 초음파 스캔에서 이상이 없으며, 혈청 AST, ALT 및 AP가 정상인 비음주자에서 경한 비포합형 고빌리루빈혈증이 있는 14예의 환자들을 대상으로 ^(99m)Tc-DISID 스캔을 시행하였으며, 기저 치 총빌리루빈 및 포합형 빌리루빈 치를 측정한 다음에 하루에 400Kcal로 48시간동안 제한한 열량 제한 시험을 시행하였고, phenobarbital을 하루 60mg씩 5일간 투여한 후에도 각각 총빌리루빈과 포합형 빌리루빈 치를 검사하여 비포합형을 구하였다. 대상 환자들은 모두 14예로서 남자가 11예(78.6%)였고 여자가 3예(21.4%)여서 3.7:1로 남자에서 많았으며, 20대가 6예(42.9%), 30대가 역시 6예(42.9%) 및 40대가 2예(14.2%)로서 2,30대가 대부분(85.8%)이었다. 열량 제한 시험 후의 총빌리루빈 치, 비포합형 및 포합형 빌리루빈 치들은 평균 각각 5.5±2.7, 4.2±2.3 및 1.3±10mg/dL 로서, 시험 전 치들인 3.0±0.8, 2.2±0.8 및 0.7±0.4mg/dL 보다 유의하게(p=0.001, p=0.001, p=0.023) 상승하였다. 포합형 빌리루빈 치도 유의하게 상승하였으나 비포합형의 상승보다는 훨씬 낮아서 주로 비포합형이 증가하였다. phenobarbital 투여 중 설사가 발생하여 중단한 1예를 제외한 13예에서 열량 제한 시험 후에 상승하였던 총, 비포합형 및 포합형 빌리루빈 치가 phenobarbital 유도 시험후에는 2.0±1.1, 1.5±0.8 및 0.5±0.4mg/dL로서 열량 제한 시험 결과보다 유의하게 낮아졌고(p=0.00, p=0.000, p=0.001), 열량 제한 시험 전의 기초치들인 3.0±0.8, 2.2±0.8 및 0.7±0.4mg.dL 보다도 더욱 낮아졌으며 유의한 차이(p=0.001, p=0.02, p=0.005)를 나타내었다. 14예에서 시행한 ^(99m)-Tc DISIDA 스캔에서 9예(64.3%)가 정상이었고, 5예(35.7%)에서는 심장 및 신장으로의 간외 섭취가 3예였고, 60분까지 소장 배출이 없는 배설 지연 예와 담낭 수축 불량 예가 각각 1예 씩 발견되었다. Phenobarbital 투여시험에서 민감도가 열량제한시험에 비해 더 높았다(92.3%와 50.0%). Gilbert 증후군에서 1일 400 Kcal로 48시간의 열량제한 시험과 1일 60mg의 phenobarbital을 5일간 투여하는 유도 시험은 편리하고 유용한 임상적인 진단법으로 이용할 수 있다고 생각된다. 그러나 열량 제한 시험에서는 증가 기준의 통일이 필요하다고 유추되며 phenobarbital 유도 시험이 민감도가 더 높은 것으로 생각된다. Gilbert's syndrome is very frequent and benign chronic process characterized by mild, intermittent, unconjugated hyperbilirubinemia without any symptom and sign of liver disease. Previously intoduced caloric restriction test and phenobarbital stimulation test as two appropriate clinical tests had been examined and their diagnostic values were reevaluated. Fourteen patients with mild, persistent, unconjugated hyperbilirubinemia were included. Subsequently caloric restriction has been applicated by 400 Kcal/day for 48 hours and phenobarbital has been prescribed by 60 mg/day for 5 days. Therafter serum levels of total and direct bilirubin were measured. Most of the patients were third and fourth decade(85.8%) and male predominant. Each basal serum levels of total, indirect and direct bilirubin were 3.0±0.8, 2.2±0.8 and 0.7±0.4 mg/dL. After caloric restriction test, each levels were increased significantly to 5.5±2.7, 4.2±2.3 and 1.3±1.0 mg/dL(p=0.001, p=0.001, p=0.023). After phenobarbital stimulation test for 13 patients had been practiced, increased levels of each bilirubin after caloric restriction test were decreased significantly to 2.0±1.0, 1.5±0.8 and 0.5±0.4 mg/dL(p=0.000, p=0.000, p=0.001) and these levels were significantly lower than basal levels(p=0.001, p=0.02, p=0.005). The sensitivities of caloric restriction test were 85.7%, 50.0%, and 71.4%, 35.7%(1.0, 1.5 mg increase of total bilirubin and 1.0, 1.5 mg/dL increase of indirect bilirubin). The sensitivities of phenobarbital stimulation test were 93.2% and 92.3% at criteria of 1.5 mg/dL increase of total bilirubin and indirect bilirubin. On the diagnosis of Gilbert syndrome, caloric restriction test and phenobarbital stimulation test are convenient and useful diagnostic tools in clinical face. And also phenobarbital stimulation test has higher sensitivity than caloric restriction test. Furthermore, standardization of bilirubin increment would be necessary in caloric restriction test.

간세포암과 감별이 어려웠던 악성중피종 치험 1예

김선문,허원석,채경훈,강윤세,정재훈,김연수,박기오,문희석,이엄석,김석현,성재규,이병석,이헌영,신경숙,조준식,송인상,강대영 충남대학교 의학연구소 2003 충남의대잡지 Vol.30 No.2

Malignant peritoneal mesothelioma is a rare neoplasm that arises from the mesothelium of a serosal cavity and is a rapidly fatal disease with a median survival of 4 to 12 months for untreated cases. Recently, we experienced a case with malignant peritoneal mesothelioma who was suspected hepatocelluar carcioma by abdominal CT scan and was confirmed by biopsy including immunohistochemical stain(calretinin) after surgery. We performed tumor excisions and wedge resection of the liver(segment Ⅷ)and inserted Tencoff catheter in abdominal cavity at 25th day of post-operation. We treated with intraperitoneal paclitaxel(25mg/m^(2)/day for 5 days) six courses monthly. She was well tolerable and is still living without any evidence of recurrence for 14th month of post-operation.

지하매설 상수도배관의 누수지점 탐지를 위한 탄성파 검출연구

이영섭,윤동진,정중채,이승석 한국비파괴검사학회 2003 학술대회 논문집 Vol.- No.1

Leaks in underground pipelines can cause social, environmental and economical problems. One of a good contermeasures of leaks is to find and repair of leak points of pipes. Leak noise is a good source to identify thc location of leak points of pipelines. Although there have been several methods to detect thc leak location with leak noise, such as listening rods, hydrophones or ground microphones, they were not so efficient tools. In this paper, two accelermeters are used to detect leak locations which could provide an easier and effcient method. The filtering, signal processing and algorithm is described for the detection of leak location. A 120m-long pipeline system for experiment is installed and the results with the system show that the algorithm with the two accelerometers gives very accurate pinpointing of leaks. Theoretical analysis of sound wave propagation speed in underground pipes is also described.

일부 도시지역 주민들의 비만도와 관상동맥질환 위험인자와의 관련성

이영선,윤석화,조영채 충남대학교 의과대학 의학연구소 2002 충남의대잡지 Vol.29 No.2

The present study was intended to reveal the relationships between the severity of obesity and various risk factors for coronary heart disease. The studs subjects were 1.838 urban inhabitants (male: 962. female: 876) who went through a general health check-up during the period between January through December. 2001. The degree of obesity was estimated by BMI and its relation to coronary heart disease risk factors were investigated. With respect to the severity of obesity. the mean systolic and diastolic blood pressure. TC. LDL-C. TG and AI increased significantly. but HDL-C showed a reversed pattern. with a higher severity. On the other hand. no difference was found in FBS. The severity of obesity was directly correlated with SBP. DBP. TC. LDL-C. TG and AI. Multivariate logistic regression analysis showed that the risk factors relevant to the severity of obesity were sex. DBP and TG. The odds ratio was 2.3 times higher in women than in men. and DBP and TG were 3.8 and 1.8 times higher in the obesity group than in the normal weight group. respectively. In conclusion. blood pressure. TC. LDL-C. TG. and AI significantly increase. and HDL-C decreases in proportion to the severity of obesity. The maintenance of desirable body weight should be a target for intervention with the idea of coronary heart disease prevention.

고압전류 감전자에게서 나타난 말초신경병증 증례보고

손준석,김영욱,채창호,민경범,이철호 대한산업의학회 2006 대한직업환경의학회지 Vol.18 No.4

Background: With increasing industrial development, opportunities are growing to contact electricity in the workplace or home. Therefore, the risk of electrical accident has been increased gradually. In general, electrical injuries involve the extremities and result in amputation or severe disability of limbs. Delayed spinal cord injury and peripheral neuropathies following electrical accidents are extremely rare. Case report: A 32-year-old man with 10 years working experience at a CRT-monitor manufacturer with repetitive exposures to high voltage current visited our hosipital. He complained of left leg weakness and atrophy, and intermittent pain. The symptoms were progressive. Other symptoms occurred such as nocturia, hesitancy, and weak urinary stream. We examined the patient and conducted EMG, L-spine MRI, neurometer test, isokinetic strength test, and physical examination. The results showed neural injuries due to anterior horn lesions or compression of the left femoral nerve pathway, with a consequent diagnosis of neurogenic bladder.

고혈압 관리를 위한 의사지원결정시스템의 데이터 마이닝 접근

강석민,조승연,채영문,김태수,호승희 대한간질학회 2003 대한간질학회지 Vol.9 No.2

好氣性 固定床 生物膜 反應槽의 메디아로 폐칫솔의 利用可能性 檢討에 관한 基礎硏究 : 처리효율을 중심으로

임채영,김정권,성낙창,신남철,김형석,전기일 동아대학교 환경문제연구소 1997 硏究報告 Vol.20 No.1

This study was conducted to evaluate the possibility to apply the waste toothbrush to aerobic fixed biofilm reactor for media. The media used for this research was waste toothbrush (WTB) and Pall-Ring. The feed used for this research was synthetic wastewater which was made at the laboratory. The COD, NH₄^(+)- N and PO₄^(-3)-P removal efficiency variations with the organic loading rate was examined at this research. The conclusions drawn from these experiments are listed below : 1. When the influent COD concentration was respectively 300mg/ℓ, 600mg/ℓ, the COD removal efficiency was decreased with the increase of the organic loading rate and the COD removal efficiency for Pall-Ring was higher than the COD removal efficiency was 0.4~1.9%. 2. When the influent NH₄^(+)-N concentration was respectively 13mg/ℓ (COD 300mg/ℓ), 25mg/ℓ (COD 600mg/ℓ ), the NH₄^(+)-N removal efficiency for Pall-Ring was slightly higher than the NH₄^(+)-N removal efficiency for Wastetooth brush. The difference of NH₄^(+)-N removal efficiency was about 0.5~1.5%. 3. When the influent PO₄^(-3)-P concentration was respectively 7mg/ℓ (COD 300mg/ℓ), 14mg/ℓ (COD 600mg/ℓ ), the PO₄^(-3)-P removal efficiency for Pall-Ring was higher than the PO₄^(-3)-P removal efficiency for Wastetooth brush. The difference of PO₄^(-3)-P removal efficiency was about 1.1~2%. 4. COD, NH₄^(+)-N and PO₄^(-3)-P removal efficiencies show very small difference between Pall-Ring and Wastetooth brush as media. So it was showed that wastetooth brush can be used as media very successfully.

관동맥풍선시술중 혈전동반 병변에 대한 구조치료(Rescue Utilization)로서의 Abciximab(ReoPro^(�)의 효과

두영철,채경수,최종형,허필석,송관욱,홍경순,박대균,한규록,오동진,유규형,임종윤,고영박,이광학,이영 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.12

성인의 동계 스포츠참여가 여가만족에 미치는 영향

성영호,채원석,정철규 龍仁大學校 體育科學硏究所 2002 體育科學硏究論叢 Vol.12 No.1

Today, leisure activities have been a critical factor to lead to satisfactory life in our society from a personal and social perspective. The study for, up to now, to describe the correlation between leisure activities and leisure satisfaction has begun since 1970s. In the early stage of the study, main concern went to the relation of leisure activities, not to the leisure satisfaction, because of the difficulty of conception and measure. The main purpose of this paper to describe the influence of participation in the ski activities on the leisure activities on the basis of pre-performed studies that a positive participation in sports activities has improved the quality of life. To this end, this paper has explaine the relation between the frequency of participation in ski activities and leisure satisfaction as well as the relation between the period of participation and leisure satisfaction. In order to this purpose, this study targeting for 155 of university students and club involvers residing in Seoul and Kunggi province and have participated in winter sports more than a year employed the systemetric random sampling method. The method to collect data from questionnaire designed for this study is based on the sports activities-related questionnaire of the Korea Sport Science Institute(KSSI) and the measure for leisure satisfaction developed by Beard and Ragheb(1980), and translated and employed by Lee, Jong Kil. Through this method, the reliability and relevance of this study have been verified. According to the reliability of the study, The reliability(a) has shown. 726-842, which is very high. For data analysis, the frequency analysis and the multivariate analysis were employed. The reault of the study based on data analysis are as follows; First, it has been revealed that the higher the frequenty of participation in ski activities, the higher(educational, social, phychological, and physiological, and environmental) leisure satisfaction. Second, The results indicates that the longer the period of participation in ski activities, the higher(educational, social, phychological, and physiological) leisure satisfaction. Also the environmental leisure satisfaction has no relation with the period of participation from a satistical viewpoint. Based upon the analysis of the results and within limitation of this study, it was concluded that the participation in the ski activities enhances leisure satisfaction