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.

마우스에 있어서 免疫反應에 미치는 마늘의 效果

黃永植,金正勳,安榮根 圓光大學校 1989 論文集 Vol.23 No.2

마늘이 아직도 世界倒處에서 많은 疾病의 治療 및 豫防의 目的으로 이용되고, 飮食의 향신료로서 마늘의 利用과 世界的 分布는 그의 人氣를 한층 더하여 주고 있다. 또한 健康專門分野에 從事하거나 硏究하는 사람들의 새로운 關心은 無毒내지 低毒性의 廣範圍 治療能을 갖는 物質이나 藥을 마늘로부터 探索하고저 하는데 집중되고 있다. 어떤 硏究報告는 많은 病原性眞菌과 細菌에 대하여 마늘推出物이 增殖沮止 또는 殺菌作用이 있다고 記述하였고, 最近의 動物實驗을 通한 硏究報告는 마늘의 高脂血症, 血液凝固, 動脈硬化症 및 低血壓 등에 대하여 有意性있는 保護作用이 있음을 밝힌 바 있다. 本 硏究의 結果 마늘이나 allicin은 體液性免疫에는 큰 影響이 없었으나 細胞性免疫은 顯著히 抑制하였고, 白血球數와 大食細胞의 活性에는 別로 影響이 없었으나 NK-cell의 活性은 그 量에 따라 增加시킴이 밝혀졌다. 이것이 抗癌作用의 動機가 된다고 思料된다. The immunomodulating and antitumor effect of raw garlic, boiled garlic and allicin were studied in mice. ICR male were divided into 10 groups and were fed on experimental diets for 4 weeks. Mice were evaluated for changes in immune status as measured by the antibody titer(HA) and hypersensitivity to sheep red blood cells(SRBC), organ weight, peripheral circulation white blood cell number, macrphage activity, and natural killer cell activity. Antitumor activity was measured by the inhibition rate of growth of Sarcoma 180. Increase of body weight was retarded, but liver weight was increased by raw garlic diets. However, spleen weight was increased by 2% boiled garlic diet and 0.002% allicin diet. Raw garlic and allicin diets suppressed the weight of thymus. Raw garlic and boiled garlic diets reduced Arthus reaction, and allicin diets reduced the delayed type hypersensitivity. HA titer and peripheral circulating white blood cell number were not affected by all experimental diets. Macrophage activities were increased by 1% raw garlic diet and 0.003% allicin diet administration. Growth rates of Sarcoma 180 were inhibited by all experimental diets administration. Especially, boiled garlic diets and allicin diets inhibited the growth of tumor. Natural killer(NK) cell activities were increased by 3% boiled garlic diet and 0.002% allicin diet administration. The data show that raw galic, boiled garlic and allicin treatment altered humoral and cell-mediated immunity. Increased NK cell activity may account for the increased resistance to challenge with tumor cells.

두가지 혈류 유발방법에 의한 새로운 심폐소생술(이중 혈류 유발 심폐소생술)장치의 개발

황성오,김현,조준휘,오범진,임종천,최경훈,윤정한,이승환,김영식,이강현,이윤선 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Background: There have been many efforts to augment blood flow during cardiopulmonary resuscitation. These efforts have focused on maximizing the effect of cardiac pump or thoracic pump alone. However, considering that the heart is the biggest blood reservoir and increase of intrathoracic pressure can generate blood flow, simultaneous exploitation of both mechanisms may have synergistic effect. We hypothesized that simultaneous chest constriction in addition to sternal compression by standard CPR may have additive hemodynamic effects by preventing deformation of the chest and increase of intrathoracic pressure. Methods and results: we built a new mechanical device to perform compression and thoracic constriction simultaneously. The device consists of two main elements. Piston in the center is to depress the sternum. Strap is to constrict the thorax circumferentially. Strap is attached to both sides of the piston. When the piston is pushed down, it depresses the sternum and pulls on the thoracic strap. To determine strap width to produce optimal hemodynamic effect, we measured hemodynamic parameters with variable widths of strap in two dogs after induction of ventricular fibrillation. Result of the experiment showed that 10cm wide strap was determined to be most effective. We also determined optimal depth of compression to produce maximal hemodynamic effect with animal experiments using two dogs. Animal experiments showed that the highest aortic pressure could be generated when the stemum was depressed to 5 cm. Cardiopulmonary resusciation using a new device could generate higher systolic aortic pressure, coronary perfusion pressure and end-tidal carbon dioxide tension in comparison with standard cardiopulmonary resuscitation in a pilot animal study using two dogs. Conclusion: New cardiopulmonary resuscitation method using a mechanical device designed by us could perform sternal compression and simultaneous thoracic constriction, and generate better hemodynamic effects than standard cardiopulmonary resuscitation in pilot animal experiments.

Ethyoene Oxide 폭로 근로자의 말초 임파구 자매염색분체 교환에 관한 연구

황천현,박종태,장성훈,김대성,이원진,김청식,김영환 大韓産業醫學會 1998 대한직업환경의학회지 Vol.10 No.4

Operators of hospital sterilizers who use ethylene oxide(EtO) were studied to determine the exposure of EtO level and the frequency of sister chromatid exchanges(SCEs) from June 12 to July 20, 1997. To evaluate SCEs in the peripheral blood cells, we selected 22 workers at the central supply room of 4 university hospitals and 22 unexposed workers at the same hospitals according to match sex, age, and smoking habit and also did questionnaires. The mean air concentrations(8-hr TWA) of EtO at 4 university hospitals were less than 1 ppm. The SCE frequencies in exposed workers to EtO and controls were normally distributed. The SCE frequencies in exposed workers to EtO and controls were 6.42±0.63, 5.86±0.69, respectively and their differences were statistically significant(p=0.0093). But there were no statistically significant differences in smoking, alcohol intake, coffee drinking. Especially smokers who exposed to EtO were increased SCE statistically significant than the exposed group who did not smoke.

색상 측정 기기를 이용한 복합레진 적층 수복과 단일 수복의 색상 비교 분석

송영상,김자현,이빈나,장지현,장훈상,황윤찬,오원만,황인남 大韓齒科保存學會 2012 Restorative Dentistry & Endodontics Vol.37 No.2

Objectives: This study analyzed the difference in color caused by different thickness in enamel layer of composite resins when applied with single and layering placement technique, and evaluated if the results agreed with the shade guide from the manufacturers to verify reliability of the color matching process of the manufacturers. Materials and Methods: For single composite resin samples, 6 mm diameter and 4 mm thickness cylindrical samples were fabricated using Ceram-X mono (DENTSPLY DeTrey) and CIE L*a*b* values were measured with spectrophotometer. Same process was done for layering compositie resin samples, making 3 dentinal shade samples, 4 mm thickness, for each shade using Ceram-X duo (DENTSPLY DeTrey) and enamel shade resins were layered in 2 mm thickness and CIE L*a*b* values were measured. These samples were ground to 0.2 mm thickness each time, and CIE L*a*b* values were measured to 1 mm thickness of enamel shade resin. Results: Color difference (△E*) between single and layering composite resin was 1.37 minimum and 10.53 maximum when layering thicknesses were between 1 mm and 2 mm and 6 out of 10 same shade groups suggested by manufacturer showed remarkable color difference at anythickness (△E* > 3.3). Conclusion: When using Ceram-X mono and duo for composite resin restoration, following the manufacturer's instructions for chossing the shade is not appropriate, and more accurate information for Ceram-X duo is needed on the variation and expression of the shades depending on the thickness of the enamel. (Restor Dent Endod 2012;37(2):84-89)

한국인 성인 남성 폐쇄성수면무호흡 환자의 측모 두부 방사선계측학적 비교

황상희,박인숙,남기영,김종배,조용원,서영성,안병훈,박신구,박효상 대한치과교정학회 2008 대한치과교정학회지 Vol.38 No.3

본 연구는 비만도에 따른 한국인 남성 폐쇄성수면무호흡 환자의 측모 두부 방사선계측학적 특성을 파악하기 위하여 시행되었다. 이를 위하여 계명대학교 의과대학 동산의료원 수면클리닉에 수면장애를 주소로 내원하여 수면다원검사 후 치과에서 측모 두부방사선계측사진 촬영을 한 87명의 성인 환자들을 체질량지수(BMI)와 수면무호흡지수(AHI)에 따라 비비만 단순코골이군(Non-obese, simple snorers), 비만 단순코골이군(Obese, simple snorers), 비비만 수면 무호흡군(Non-obese, OSA patients), 비만 수면무호흡군(Obese, OSA patients)의 4군으로 나누어 비교하였다. 그결과, 4군 중 비만 수면무호흡군의 수면무호흡지수가 가장 컸으며, 비만 수면무호흡군보다 비비만 수면무호흡군의 하악각이 더 크고 혀 길이는 더 작았다. 또한, 비비만 수면무호흡군보다 비만수면무호흡군의 설골이 더 전하방에 위치하였고, 수면무호흡지수에 영향을 미치는 기여 인자는 비만 수면무호흡군에서는 혀 길이, 비비만 수면무호흡군에서는 설골의 후방위치였다. 이처럼 비만 수면무호흡 환자와 비비만 수면무호흡 환자의 측모 두부방사선계측학적 특성과 기여 인자가 다르게 나타나므로, 치료방법도 따라서 다르게 선택해야 할 것이다. 비만 수면무호흡 환자들에게는 먼저 체중감량이 권고되어야 할 것이고, 비비만 수면무호흡 환자들은 폐쇄부위에 따라 구강 내 장치나 Nasal CPAP (continuous positive airway pressure), UPPP (uvulopalatopharyngoplasty) 등이 추천될 수 있을 것이다. Objective: The purpose of this study was to compare the cephalometric measurements of obese and non-obese Korean male patients with obstructive sleep apnea syndrome (OSA). Methods: Eighty-seven adults who had visited the Sleep Disorder Clinic Center in Keimyung University, Daegu, Korea were examined and evaluated with polysomnography (PSG) and lateral cephalogram. They were divided into 4 groups (non-obese simple snorers, obese simple snorers, non-obese OSA patients, obese OSA patients) according to AHI (Apnea-Hypopnea Index) and BMI (Body Mass Index). Results: The obese OSA group had the highest AHI among the 4 groups. The non-obese OSA group had a significantly steeper mandibular angle and shorter tongue length than the obese OSA group. The hyoid bone of the obese OSA group was positioned anterior and inferior as compared with the non-obese OSA group. Multiple regression analysis showed that tongue length in the obese OSA group and retroposition of hyoid bone in the non-obese OSA group were significant determinants for the severity of AHI. Conclusions: From a cephalometric point of view, the obese and non-obese pateints with OSA may be characterized by different pathogeneses. Therefore, they have to be managed by individualized treatment. For the obese OSA patients, weight control must be advised as a first choice and for the non-obese OSA patients, oral appliance, nasal CPAP, UPPP and others could be chosen according to the obstructive sites.

e-Learning에서의 효율적인 온라인학습 전략 탐색

소훈,황영성 釜山大學校 附設 體育科學硏究所 2007 體育科學硏究所 論文集 Vol.23 No.2

본 연구는 e-Learning의 등장으로 많은 변화를 요구받고 있는 교육 현장의 당사자인 교수자와 학습자 측면에서 성공적이고 효율적인 온라인 학습전략의 기본적인 틀을 제시하는 것으로 다음과 같은 전략적인 시사점을 도출하고 있다. 첫째, 학습자의 만족과 지속적인 학습을 위한 체계적인 콘텐츠의 개발이 우선되어야 할 것이다. 둘째, 교수자와 학습자 간의 활발한 커뮤니케이션을 지원하는 솔루션이 확보되어야 한다. 셋째, 교수자와 학습자의 상호작용을 통한 친밀한 관계형성이 필수조건이다. 넷째, 다양한 매체 전달 양식 중, 학생들이 선호하는 매체의 표현방법의 설정이다. 따라서 다양한 매체 중 학습자 특성에 맞는 매체 유형을 선택하여 제공한다면 학습자의 선호도와 만족도를 이끌어 낼 수 있는 방법이 될 것이다.

인공 치아우식 발생 모델에서 디지털 방사선 공제술을 이용한 인접면 치아우식증의 진단

박정훈,최용석,황의환,이기자,최삼진,박영호,김경숙,진현석,홍경원,오범석,박헌국 대한구강악안면방사선학회 2009 Imaging Science in Dentistry Vol.39 No.1

Purpose : The purpose of the experiment was to evaluating the diagnostic ability of dental caries detection using digital subtraction in the artificial caries activity model. Materials and Methods : Digital radiographies of five teeth with 8 proximal surfaces were obtained by CCD sensor (Kodak RVG 6100 using a size #2). The digital radiographic images and subtraction images from artificial proximal caries were examined and interpreted. In this study, we proposed novel caries detection method which could diagnose the dental proximal caries from single digital radiographic image. Results : In artificial caries activity model, the range of lesional depth was 572-1,374 μm and the range of lesional area was 36.95-138.52mm². The lesional depth and the area were significantly increased with demineralization time (p<0.001). Furthermore, the proximal caries detection using digital subtraction radiography showed high detection rate compared to the proximal caries examination using simple digital radiograph. Conclusion : The results demonstrated that the digital subtraction radiography from single radiographic image of artificial caries was highly efficient in the detection of dental caries compared to the data from simple digital radiograph.

모 중장비 제조 사업장의 유해작업요인 평가에 관한 연구

장성훈,이원진,서창호,김종규,이영신,황천현,서동윤 건국대학교 의과학연구소 1996 건국의과학학술지 Vol.6 No.-

We evaluated the types and the amount of hazards in a heavy equipment factory and a plant factory to improve workers' health and to determine the priority in occupational health programs. We first inspected the working processes to find hazardous agents, measured them in each process environment, and compare the results with their TLVs(Threshold Level Value). This study was carried out from December 26, 1995 to January 30, 1996. The results are as follows: 1. In two factories, we identified the following hazardous agents: noise, dust, heavy metal fume, organic solvents, illumination, gases and ultraviolet light. 2. In the heavy equipment factory, some agents were over their TLVs in the following departments. 1) Preparation Department: dust, Pb, Mn, Fe₂O₃, NO₂ 2) Manufacture Department: noise, dust, Pb, Mn, Fe₂O₃, NO₂ 3) Assembly Department: noise 4) Technique Department: NO₂ 3. In the plant factory, some agents were over their TLVs in the following departments: 1) 1 Bay: illumination, Pb, Mn, Fe₂O₃ 2) 2 Bay: dust, illumination, Cu 3) 3 Bay: illumination 4) 4 Bay: noise, dust, Pb, Mn, Fe₂O₃, NO₂ 5) 5 Bay: noise, dust, Pb, Mn, Fe₂O₃, NO₂ 6) 6 Bay: Pb, Mn, NO₂ We concluded that the hazardous agents such as heavy metal fume, noise and noxious gas were required to be controlled at first.

우울장애 환자에서 자살 시도와 트립토판 수산화 효소(Tryptophan Hydroxylase) A218C 유전자 다형성과의 관련성

심세훈,황보영,권영준,정희연,이분희,김용구 대한신경정신의학회 2008 신경정신의학 Vol.47 No.2

Objectives : Several lines of evidence suggest the serotonergic dysfunction involved in the biological susceptibility of suicide. Tryptophan hydroxylase (TPH), the rate-limiting enzyme in the biosynthesis of serotonin, Plays a vital role in serotonin metabolism. In a case-control study, we investigated whether the TPH gene was a susceptible factor for suicidal behavior in depressive patients. Methods : The subjects were 218 depressed patients who attempted suicide and visited emergency rooms in multi-medical centers. One hundred thirty hospitalized non-suicidal depressed patients and the 161 normal controls were matched with the suicidal group. Individuals in all 3 groups were evaluated independently by a Structured Clinical Interview for the purpose of establishing a DSM-IV criteria diagnosis (SCID). The severity of depressive symptoms was evaluated using Hamilton depression rating scale (HDRS). Results : There was no significant difference in genotype distributions and allele frequencies of TPH intron 7 A218C polymorphisms among 3 groups. Furthermore, no significant difference in genotype counts and allele frequencies of the polymorphisms was found among lethal suicidal depressed patients, non-suicidal depressed patients and the normal controls. Conclusion : This study suggests that the A218C polymorphism of the TPH gene is unlikely to have a major effect on the susceptibility of suicidal behaviors in depressive patients.