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.

In Vitro에서 골 형성과 흡수에 대한 Endothelin-1의 영향

사석진,안도환 고신대학교 의과대학 2010 고신대학교 의과대학 학술지 Vol.25 No.2

Background: Balanced regulation of the receptor activator of nuclear factor-kB (RANK) ligand (RANKL) and osteoprotegerin (OPG) by osteoblasts is important for osteoclastogenesis. Sex hormones, glucocorticoids, and prostaglandin E2 (PGE2) are known to modulate osteoblast proliferation and osteoclast formation. Endothelin (ET)-1 is a mitogen as well as a strong vasoconstrictor.It stimulates proliferation of osteoblasts, but its effects on differentiation are controversial. In addition, little is known about ET-1 regulation of osteoclast formation. Thus, the present study was undertaken to investigate whether ET-1 canregulate the expression of RANKL and OPG genes in osteoblasts and affect RANKL-induced osteoclastogenesis. Methods: Osteoblasts were derived from neonatal calvariae and monocytic preosteoclasts from the bone marrow of adult mice, respectively. Cells were cultured in a-minimum essential medium containing 10 nM ET-1. The gene expressions of RANKL and OPG in osteoblasts and RANK in preosteoclasts were measured by real-time RT-PCR. Mineralization by osteoblasts was determined by Alizarin-red staining. Osteoclastogenesis was examined using tartrate-resistant acid phosphatase (TRAP) staining and resorption pit assay. Results: Osteoblasts expressed both ETA and ETB receptors (ETAR and ETBR). ET-1 (10 nM) increased osteoblast proliferation 1.6-fold compared with the control after 3 days in culture and stimulated differentiation, which was indicated by increased formation of mineralized matrix. Proliferation and differentiation of osteoblasts was blocked by 1 uM BQ123, an ETAR antagonist. ET-1 suppressed RANKL gene expression by 50% but did not affect OPG gene expression, and thus reduced the ratio of RANKL to OPG mRNA. PGE2 production by osteoblasts was increased by ET-1. In preosteoclast cultures, ET-1 had little effect on RANK mRNA expression and suppressed RANKL-induced osteoclastogenesis by decreasing the number of TRAP-positive osteoclasts and the resorbed areas. Conclusions: These findings demonstrate that ET-1 can increase bone formation by stimulating proliferation and differentiation of osteoblasts and decrease bone resorption by suppressing RANKL-induced osteoclastogenesis as well as suppressing RANKL mRNA expression In vitro에서 골 형성과 흡수에 대한 endothelin-1의 영향 배경: 조골세포에서 생성되는 receptor activator of nuclear factor-kB ligand (RANKL)과 osteoprotegerin (OPG) 사이의 균형은 파골세포 형성에 매우 중요하다. Enodothelin-1(ET-1)은 강력한 혈관수축제일뿐만 아니라 다양한 세포에서 세포 증식을 촉진시키는 물질이다. 그러나 ET-1의 조골세포의 분화에 대한 영향은 상반될 뿐만 아니라 ET-1이 조골세포의 RANKL과 OPG의 생성을 변화시켜 간접적으로 파골세포 형성에 영향을 주는지 혹은 파골세포의 분화에 직접적으로 영향을 주는지에 대해서는 연구된 바 없다. 따라서 본 연구에서는 ET-1에 의한 조골세포의 분화와 RANKL 및 OPG 유전자 발현이 파골세포 형성에 미치는 영향을 조사하였다. 재료와 방법: 조골세포는 생쥐의 두개골로부터 그리고 파골전구세포는 골수로부터 각각 분리하였다. 이들 세포들을 10 nM ET-1이 포함된 α-MEM 배지에서 배양하였다. 유전자의 발현은 real-time RT-PCR을 통해 정량적으로 측정하였다. 조골세포의 분화는 alizarin-red 염색으로, 파골세포의 형성과 활성은 tartrate-resistant acid phosphatase 염색과 골 흡수와(resorption pit)의 크기로 평가하였다. 결과: ET-1은 조골세포의 증식과 분화를 촉진시켰으며, 이는 ETA 수용체를 통해 이루어졌다. 조골세포에서 ET-1은 PGE2 생성을 크게 증가시켰을 뿐만 아니라 RANKL 유전자 발현을 대조군에 비해 50% 감소시켰다. 그러나 OPG 유전자의 발현에 영향을 주지 않았다. 파골 전구세포에서 ET-1은 RANK 유전자의 발현에 영향을 주지 않았지만 RANKL에 의해 유도된 파골세포 형성과 활성은 억제시켰다. 결론: ET-1은 조골세포의 증식과 분화를 촉진시키고 RANKL mRNA 발현을 감소시켜 파골세포 형성을 간접적으로 억제한다. 또한 RANKL에 의해 유도되는 파골세포 형성과 활성을 직접적으로 억제한다. 이러한 결과로 미루어 ET-1은 골형성은 촉진하고 골흡수는 억제할 것으로 사료된다.

세팍타크로 경기의 공격기술과 공격포지션에 따른 성공률 분석

김석주,김세환 江原大學校附設體育科學硏究所 2003 江原大學校附設體育科學硏究所論文集 Vol.- No.26

The purpose of this study is to expand the base of population for Sepaktakraw, through enhancing an interest in the event of Sepaktakraw, to seek for a scientific and systematic training method, by particularly finding out which attack-skill type and attack position are more important among competitions, and to obtain the reference data helpful to coaching a player such as the enhancement of sports performance and the operation of competitions. Aiming to achieve this goal of a study, targeting players who did take part in the competitions of Sepaktakraw by event for men and women nationwide, 1) it did analyze the attempt rate and success rate for male and female players depending on an attack-skill type, 2) it did survey and analyze the attempt frequency, attempt rate, success frequency and success rate depending on the attack position (a left striker, a right striker), thus it did obtain the conclusions as follows. First, as a result of analyzing the attempt rate and success rate depending on a type of attack skills, in terms of a type of attack skills, it was shown to be highest in the attempt rate and success rate of scissors spike, as for both men and women, and it was shown to be the highest in the attempt rate and success rate of rolling spike as to high-school division by event for men. Second. as a result of analyzing the attempt rate and success rate depending on attack positions, in terms of attack positions, it was shown to be highest in the attempt rate and success rate of right-striker attack, as for both men and women, and in relation to right-striker attack. the high-school department was shown to be higher in the attempt rate and success rate than the university division and the general division, in any event for men.

한국 연안 퇴적물에서 ^137Cs, ^90Sr 및 Pu 동위원소의 분포

최석원,진현국,김철수,노정환,김창규,노병환 대한방사선 방어학회 2002 방사선방어학회지 Vol.27 No.2

한국 주변 연안 15개 정점의 퇴적물(0∼20 cm)에서 ^137Cs, ^90Sr, ^239+240Pu 의 농도와 농도비를 조사했다. ^137Cs, ^90Sr, ^238Pu 및^239+240Pu의 평균 방사능 농도는 각각 2.24±0.79 Bq·kg^-1-dry, 0.20±0.04 Bq·kg^-1-dry, 0.009±0.005 Bq·kg^-1-dry 및 0.27±0.17 Bq·kg^-1-dry이다. ^137Cs/^90Sr, ^239+240Pu/^137Cs 및 ^238Pu/229+240Pu의 평균 농도 비와 ^239Pu/240의 평균 원자 비는 각각 11.2±2.9, 0.123±0.053, 0.033±0.01 및 0.218±0.036이다. 퇴적물에서 핵종의 농도 범위와 핵종간의 농도 비는 그 동안 주변국가의 퇴적물에서 조사한 값과 비슷하였다. 퇴적물에서 ^137Cs과 ^239+240Pu의 상관계수는 0.80이다. ^137Cs과 SOM, ^239+240Pu과 점토 함량과의 상관계수는 각각 0.69, 0.67 이다. The concentrations and activity ratios of ^137Cs, ^90Sr, ^238Pu and ^239+240Pu in sediment(0∼20 cm) at 15 coastal stations of Korea were determined. The mean concentrations of ^137Cs, ^90Sr, ^238Pu and ^239+240Pu are 2.24±0.79 Bq·kg^-1-dry, 0.20±0.04 Bq·kg^-1-dry, 0.009±0.005 Bq·kg^-1-dry and 0.27±0.17 Bq·kg^-1-dry, respectively. The mean activity ratios of ^137Cs/^90Sr, ^239+240Pu/^137Cs and ^238Pu/^229+240Pu and atomic ratio of ^240Pu/^239Pu are 11.2±2.9, 0.123±0.053 and 0.033±0.017 and 0.218±0.036, respectively. The concentrations and activity ratios in sediment samples are similar to those reported from neighbouring country in the northern hemisphere. The correlation coefficient of ^137Cs and ^239+240Pu is 0.80. The correlation coefficient of ^137Cs and soil organic matter(SOM), and ^239+240Pu and clay content are 0.69 and 0.67, respectively.

응급실 자의퇴원환자의 요인분석

김승환,김옥준,장석준,정구영,김승호 대한응급의학회 1993 대한응급의학회지 Vol.4 No.2

Discharge against medical advice(AMA) in the emergency department is a frustrating, painful event to both patients and emergency physicians and emergency physicians. A retrospective chart review of 347 consecutive AMA patient from our emergency department from December 1992 to May 1993. Among them, 185 patients were interviewed with our researcher about primary cause of AMA through telephone contact. The results were as follows : 1. Total 9,705 patients visited our emergency department during 6-months period and there was 347 AMA patients(3.6%) 2. The main reasons for 185 AMA were ; 1) patients' or family's own problem in 114 cases(61.6%) 2) changes in patient condition(terminal case, improvement) in 56 cases(30.3%). 3) dissatisfaction to medical services in 15 cases(8.1%) 3. During same period, there was 117 cases of drug intoxication mainly due to suicidal attempt and 18 AMA was noted. Among 18 AMA cases, 16 patients discharged against medical advice due to patients' own problem(mainly due to economical problem) but none of them revisited OPD or emergency department. 4. Eight of 40 AMA patients with symptom improvement were managed in OPD, emergency department or other hospital but none of them admitted. In conclusion, we noticed that the main cause of AMA is non-medical problem in Korea and there should be continuous effert to improve our medical insurance system, emergency medical services system. Only through the judicious use of AMA, it can be used as a tool of determining patient satisfaction and quality improvement in emergency medical field.

답손(Dapsone)중독환자의 예후와 특성 분석

장석준,정성필,김승환,구홍두,심호식 대한응급의학회 1995 대한응급의학회지 Vol.6 No.1

We reviewed 26 dapsone intoxication patients who had visited Severance Hospital Emergency Care Center from January 1991 to January 1995 : 13 of them ingested intentionally, but the other ingested accidentally. Among the admitted patients the highest and lowtheest initial value of methemoglobin level is 59.6% & 10.1%. The frequency of symptoms at presentation was following 16 patients complained cyanosis of lip area, 10 patients complained dyspnea, 4 patients complained mental change, 4 patients complained vomiting, 2 patients complained nausea. The inital level of methemoglobin was less than 50% except in one patient. In the view points of total doses of methylene blue used, less than 100mg was used in 9 patients(34.6%) but in one case, amount of 6400mg was loaded. There were 5 patients(19.2%) in September & 4 patients (15.4%) in January. In respect of result, there were 13 discharged cases (50%) for symptom improvement, and 5 mortality cases(19.2%). The transferred cases from Gangwondo account 19 patients(73.1%). All of them is not directly emergency care center visiting patients but transferred patients from remotely located hospitals. Dapsone intoxication results in severe tissue hypoxic symptoms from malfunction of normal hemoglobin thus only with appropriate available doses of methylene blue & activated charcoal, good outcomes will be expected. If aggressive therapy such as hemodialysis is introduced in treatment of severe dapsone intoxication, the outcomes may be slightly improved better than in other supportive care cases.

기관내 삽관이 어려웠던 폐동맥 sling을 동반한 기관협착 환아1예

염석란,신중호,신종환,이근,류일,현성열,진욱,김재광 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

Pulmonary arterial sling, a rare developmental vascular anomaly forms a sling around the distal trachea and the proximal right main bronchus, where it sometimes makes tracheo-bronchial stenosis. Tracheo-bronchial stenosis from pulmonary arterial sling may produce non-specific symptoms of stridor, noisy breathing, dyspnea, recurrent upper respiratory tract infection, chronic cough, and dysphagia. The diagnosis of this anomaly begins with a high index of suspicion because of the lack of pathognomonic finding on usual evaluation. In this case, initial difficult intubation makes us evaluate further. Other cases reported the diagnosis is established by imaging studies, usually MRI and angiography. But, when our case was evaluated, we used cervico-thoracic enhanced computered tomography and tracheal fluoroscopy. Up to now, tracheobronchial stenosis from vascular anomaly is a rare and challenging disorder with a poor prognosis. However, early exact diagnosis would make us perform the accurate surgical treatment and reduce the mortality and morbidity.

만성 불안정 무지 중수지절의 치료 : 단무지 신전근 또는 장 수장근을 이용한 측부인대의 재건 Reconstruction of the collateral ligaments using the extensor pollicis brevis or palmaris longus

이승구,송석환,윤화주 최신의학사 1990 最新醫學 Vol.33 No.9

무한증을 동반한 선천성 동통 무감각증 : 1예 보고 Report of A Case

김진영,송석환,조성일,공준택 최신의학사 1991 最新醫學 Vol.34 No.1

수부의 외상성 중수지 관절 탈구의 치료

이승구,송석환,이주엽,문창윤,오재찬 대한골절학회 2003 대한골절학회지 Vol.16 No.2

목적 : 수부의 중수지 관절 탈구의 관혈적 정복이 필요했던 예에서는 정복을 방해하는 구조물에 대해 분석하고 도수 정복이 가능했던 예에서는 성별 및 탈구 형태에 따른 특성에 대해 알아보고자 하였다. 대상 및 방법 : 총 27예의 수부 중수지 관절 탁구 환자 (무지 11예, 이지 14예, 소지 2예)를 대상으로 연구하였다. 탈구된 중수지 관절의 정복을 방해하는 해부학적 구조는 수술시에 확인을 하였으며, 도수 정복이 가능하였던 예들에서도 연령과 손상된 구조물, 그리고 최종적인 임상 결과를 평균 7개월간 추시 관찰하였다. 결과 : 무지 중수지 관절의 탈구 11예 중 파열된 전방 관절낭, 수장판과 단무지 굴건의 파열을 동반한 복합 탈구가 8예 있어 관혈 정복을 시행하였으며, 2예에서만 도수 정복이 가능하였다. 관절염이 있던 1예는 관절 유합술을 시행하였다. 다른 수지의 중수지 관절의 탈구는 Kaplan의 개념에 따라 탈구를 수술 정복하였고 파열된 수장판을 복원하였으며, 1예에서 수술시 표재 중수 횡인대만의 절개와 이완으로 정복할 수 있었다. 소지 중수지 관절 탈구의 2예에서 파열된 요측 측부인대가 수술시 관찰되었고 이를 복원하여 수지의 불안정성을 예방하였다. 이들의 최종 결과는 특별한 운동 제한이나 불안정성 없이 좋은 결과를 보였다. 결론 : 적절한 국소 마취하에 도수 정복을 1~2회 시행할 수 있지만 단순 정복이 가능한 탈구가 부적절한 견인으로 정복이 불가능한 복합 탈구로 진행할 수 있다. 그리고 복합 탈구는 대부분 관혈적 정복이 필요하기 때문에, 정복 방해 구조물에 대한 충분한 이해와 적절한 조치가 필요하다. Purpose : To analyse the obstacles to prevent the reduction for dislocation of the metacarpophalangeal (MP) joints of the hand and evaluate the relationship between the sex and dislocation type in closed reduction case. Materials and Methods : Total 27 cases of MP joint dislocation of the hand (11 cases of thumb, and 14 index and 2 little finger) were reviewed retrospectively. The anatomical structures to prevent the reduction were confirmed at operation and the cases which were reduced immediately were also analysed for their ages and differences of damaged structures, and finally their complications or outcome were reviewed for average 7 months after reduction. Results : In 11 cases of thumb MP joint dislocations, the complex dorsal dislocations in which the protruded metacarpal neck was caught by buttonhole of torn anterior joint capsule, volar plate and FPB were reduced by open method in 8 cases, and closed reduction was done in 2 cases but one old case required arthrodesis. In other finger MP joint dislocations, the Kaplan's concept to prevent the reduction was confirmed. But reduction of torn volar plate and incision of transverse metacarpal ligament were sufficient to reduce the dislocation with gentle longitudinal traction during the operation. In two cases of little finger MP joint dislocation, the ruptured radial collateral ligaments were noted after open reduction and it must the repaired to prevent the finger instability later. Their overall end results were good without any significant restriction of MP joints motions and finger instabilities. Conclusion : One or two times of closed reduction with proper local anesthesia could be tried, but simple reducible dislocation can be converted to complex irreducible ones by the inappropriate traction method, and so proper reduction technique by closed or even in open way is important with the knowledge of anatomical obstacles to prevent the reduction of the metacarpophalangeal joints.