Microstructure and Tensile Properties in Low Pressure Cast Al-Si Alloy through Cooling Rate Control

Suh, Jun-Young,Park, Sung Jin,Lee, Hee-Kwon,Chang, Si Young Materials Research Society of Korea 2020 한국재료학회지 Vol.30 No.2

In this study, three kinds of metal chills such as SS400, AC4CH and brass, with different thicknesses of 40 ~ 80 mm, were applied for low pressure casting of Al-Si alloy to control cooling rate. The microstructural characteristics with increasing cooling rate were represented using factors including D₁, D₂, size of primary α phases and shape factor and size of eutectic Si. The tensile properties were investigated and additionally analyzed based on the microstructural characteristics. As the cooling rate increased, D₁, D₂, and sizes of primary α phases and eutectic Si apparently decreased and the shape factor of eutectic Si increased to over 0.8. The ultimate tensile strength (UTS) and yield strength (YS) increased with decreasing D₁, D₂, and size of primary α phases, while elongation increased with decreasing size of eutectic Si and concurrently increasing shape factor of eutectic Si. This indicated that the primary α phases and eutectic Si in Al-Si alloy were refined with increasing cooling rate, resulting in improvement of UTS and YS without sacrificing elongation. After the tensile test, preferential deformation of primary α phases was observed in the Al-Si alloy produced at higher cooling rates of more than 0.1 K/s.

고령자 급성 췌장염의 임상적 고찰

이진헌,강진경,박인서,송건훈,정재복,백용한,송시영,서정훈 대한소화기학회 1998 대한소화기학회지 Vol.32 No.3

Background/Aims: Inflammatory diseasas of the pancreas are not uncommon. The advanced age is one of the significant factors in assessing the severity of acute pancreatitis. It has been shown that the biliary tract disease is a more frequent cause of acute pancreatitis in the elderly than in the young. With the increased life span, the elderly are comprising a large proportion of the population. As a result, physicians are more often being faced with acute pancreatitis in the elderly. The purpose af this study was to evaluate clinical features of acute panereatitis in the elderly. Methods: A total of 188 patients with acute pancreatitis were reviewed. We investigated the differences of clinical characteristics between the elderly patients aged over 60 and the young patients aged under 60. Results: The sex distribution showed male preponderance in the young patients (M:F=2.4:1), but was nearly equal in the elderly patients (M:F=1.1:1). The most common cause of acute pancreatitis in the elderly was biliary tract disease (52.5%), while alcohol abuse was the most common cause in the young patients (38.8%), Local complications of acute pancreatitis, such as psuedocyst, necrosis, abscesses were not differently shown between the elderly (16.9%) and the young (20.2%) patients. Systemic complications including acute puhnonary failure occurred more frequently in the elderly patients than the young patients. The mortality rate of the elderly patients (5.1%) was not significantly different from that of the young patients (3.1%). Conclusions: To detect correctable underlying bihary tract diseases the elderly patients with acute pancreatitis should be completely investigated using endoscopic retrograde cholangiopancreatography (ERCP). In addition, the patient should be closely monitored for the development of the systemic complications during the disease process.

고령자 급성 췌장염의 임상적 고찰

백용한,서정훈,송건훈,이진헌,송시영,정재복,강진경,박인서,이수진 大韓消化器病學會 1998 大韓消化器病學會誌 Vol.32 No.3

내시경적 조임근절개술후에 발생한 췌십이지장 가성동맥류 1예

박수영,김윤정,박진한,전현수,박시형,이영진,이은지,김지현 仁濟大學校 白病院 2010 仁濟醫學 Vol.31 No.-

We reported a case of pancreatic pseudoaneurysm, involving pancreaticoduodenal artery, developed after endoscopic retrograde cholangiopancreatography(ERCP) with endoscopic sphinterotomy. A 54 year old woman was transferred to our hospital due to sustained hematochezia and hypovolemia. A week before admission, she underwent ERCP with endoscopic sphinterotomy for acute cholangitis in local clinics. She developed abdominal pain and hematochezia at 12 hours after the procedures. A post procedure contrast enhanced computed tomography of abdomen demonstrated a pseudoaneurysm in inferior portion of pancreatic head. This was not present on the pre procedure contrast enhanced computed tomography of abdomen and was thought to arise from the pancreaticoduodenal artery as a complication of the pre sphincterotomy. She was brought to our emergency room in a state of hypovolemia. A upper endoscopy showed active bleeding from ampula of vater. An celiac angiography demonstrated pancreatic pseudoaneurysm involving inferior pancreaticoduodenal artery and selective coil embolization of was performed.

지능형 자동차 주변 감시 시스템 설계 방안

장시웅(Si-woong Jang),박영식(Young-sik Park),성현용(Hyun-yong Sung),곽길봉(Gil-bong Kwak),김선남(Seon-nam Kim),김경진(Kyeoung-jin Kim) 한국정보기술학회 2009 Proceedings of KIIT Conference Vol.2009 No.-

본 연구는 차량 주변을 지능적으로 감시하는 자동차 주변 감시시스템에 관한 것으로, 자동차의 주행 및 주차 시 속도의 변화나 운전자의 요청에 의해 자동차 주변 지역에 관한 시야를 상황에 따라 달리하여 모니터링 함으로써 운전자가 안전한 주행 및 주차를 수행할 수 있게 하기 위한 것이다. 그러한 목적을 달성하기 위하여 본 연구에서는 차량의 주변부를 감시하기 위하여 차량의 외곽에 설치된 카메라의 각도가 지면으로부터 차량의 상부를 향하는 방향으로 변경될 수 있도록 제어하는 제어부, 카메라의 영상을 입력받아 차량주변의 영상을 생성하는 영상처리모듈, 영상처리모듈에서 생성된 영상을 출력하는 디스플레이를 포함하는 것을 특징으로 하는 지능형 자동차 주변 감시시스템을 제안한다. This study is on a vehicle surroundings monitoring system, which enables a driver to travel and park safely by monitoring vehicle surroundings, depending on the speed of vehicle and driver's control when traveling and parking. To achieve the aforementioned purpose, we propose an intelligent vehicle surroundings monitoring system, which consists of a control part, an image processing module and display module. Hence, the control module controls angle of camera to turn upward from the bottom to monitor vehicle surroundings. The image processing module merges the received images from cameras with the original vehicle image to display the vehicle’s surroundings in real time as if looking down from the sky.

複合 韓藥劑 淸籬滋坎湯의 抗癌效果 및 作用機轉 糾明

Cho, Kyung-Sam,Kim, Si-Young,Park, Jai-Kyung,Choi, Seung-Hoon,Chung, Se-Young,Yoon, Hwi-Joong 경희대학교 동서의학연구소 1999 INTERNATIONAL SYMPOSIUM ON EAST-WEST MEDICINE Vol.1999 No.1

Kyung Sam Cho¹Si Young Kim¹, Jai Kyung Park²,Seung Hoon Choi³,Se Young Chung⁴, Hwi Joong Yoon¹¹College of Medicine, ²East-West Medical Research Institute, ³College of Oriental Medicine, ⁴College of Pharmacology, Kyung Hee University,Seoul, Korea. The Anti-cancer Effect of Oriental Medicine Chung-Ri-Ja-Gam-Tang in the Mouse with Metastatic Lung Cancer. Proceedings of International Symposium on East-West Medicine, Seoul. 231-243, 1999.-The oriental medicine Chung-Ri-Ja-Gam-Tang is an herbal medicine which has been used for pulmonary diseases and known as having immune stimulatory effects. It has been known effective in lung cancer. So we studied the effects and the mechanisms of this herbal medicine it the mouse with metastatic lung cancer. The metastatic lung cancer of the mouse was produced with melnoma cell line(B16BL/6).5×10□/mouse tumor cells were injected intravenously to the CDF1 mouse via tail vein. The mice were divided 4 groups. The first group was treated with 50mg/kg extract of Chung-Ri-Ja-Gam-Tang per oral for 10 days after cancer cell injection, second group treated with saline after cancer cell injection, the third group with medicine without cancer cell, and the last group with saline only. After 10 days treatments some of the mice were scarificed and the lung and spleen was removed. The survival duration, weight change, the number of metastatic cancer nodule of the lung, the NK cell activity, the capacity of cytokines(INF-γ,INF-α,IL-2) production and the proliferation activities of mouse lymphocytes were measured. The surival times of the group 1 mice were longer and the weight loss was less than the group 2 significantly. The number of the metastatic nodule of the lung were decresed in the group 1 than the group 2. The production of INF-γ,was increase in group 2 than group 3 and 4, IL-2 production was increased in group 1 than group 2,3,4 significantly. There was no difference in TNF- α production and proliferation activity of lymphocyte in each group. The NK cell activity was significantly increased in group 1 than group 2,3,4. We conclude that the Chung-Ri-Ja-Gam-Tang has the effect of increasing the NK cell activity of the CDF1 mouse with metastatic lung cancer(B16BL/6). And it is suggested that the increased production of the IL-2 is the mechanisms of enhanced NK cell activity.

E. coli 과량발현을 통한 B형 간염 바이러스 preS1 유도체의 안정한 동위원소 N의 치환

박병관,김세하,한규훈,김선영,홍요정,이시형,한동설,김순종,박진구 木浦大學校基礎科學硏究所 1997 基礎科學硏究誌 Vol.15 No.-

We have used molecular biology technique to label the side chains and backbone of HBV preS1(1-56) with stable isotope (??) during E. coli over-expression and purified the protein to near homogeneity. The expression level of ?? labelled preS1(1-56) seems to be ∼15% of the total protein. to characterize the secondary structure of the labelled protein, circular dichroism was used. In different buffer conditions including pH 3.3 and pH 7.4 the protein seems to be devoid of any stable secondary structure probably suggesting that the N-terminal portion (preS1(1-56)) of HBV preS1 might be unstructured before binding to its target cells.

법랑질 형성 부전증에 관한 증례 보고

박종하,김재곤,백병주,허선,이영수 大韓小兒齒科學會 1998 大韓小兒齒科學會誌 Vol.25 No.3

본병원 소아치과에 내원한 유치와 영구치 모두에 법량질 형성 부전증을 가지고 있는 환자에 대해 교합면의 마모를 방지하여 교합고경을 유지하기 위해 유구치부 stainless steel crown 및 맹출 중인 제 1대구치에 sealant, 전치아에 걸쳐서 주기적인 불소도포를 이용해 치료하여 양호한 결과를 얻었다. Amelogenesis imperfcta is a group of hereditary defects of enamel unassociated with any other generalized defects. The prevalence of this condition has been estimated to range from l in 14.000 to l in 16.000. depending on the population sudied. It may be differentiated into three general types: hypoplastic, hypocalcified. and hypomaturation. depending on the clinical presentation of defects and the likely stage of enamel formation that is primarily affected. The dentin and root are usually normal. but the enamel may lack the normal prismatic structure, being laminated throughout its thickness or at the periphery, with the result that these teeth are more resistant to decay. This case is that of an six-year-old girl brought to the pediatric dentistry department by her parents for esthetic reasons and also because of slight dental sensitivity. Clinical and radiographic examinations confirmed amelogenesis imperfecta. The author has treated with the crowning of the primary molars, using prefomed NICr crowns and periodic and periodic fluoride application on whole dentition.

Most Probable Number 방법을 이용하여 측정한 중랑천 河床土壤의 혐기성 세균의 수와 수질과의 상관 관계

박두현,김병홍,임시근,최영효 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.3

중랑천의 하상 토양의 혐기성 호흡세균의 분포를 MPN법으로 조사하였다. 철이온환원세균을 조사하기 위해 배양액 중의 Fe(Ⅱ)을 확인하는 변형된 oxalate-ferrozine 법을 개발하였으며, 황산염환원세균(SRB)과 메탄생산세균을 각각 FeS 침전과 head space의 CH_4를 검출하는 방법을 채택하여 중랑천 지천과 본천의 혐기성 미생물 분포를 조사한 결과 오염 정도가 상대적으로 높은 본천에서 철이온환원세균이 10^7~10^8 cells/g 정도로 조사되었으며 지천의 경우 10^7 cells/g이었다. 우이천 상류를 제외한 모든 조사 지점에서 SRB와 methanogen 이 10^3 cells/g이었다. 이 결과는 분류 하수관의 설치로 유기물의 유입이 낮아진 조건에서도 하상의 침전층에서 유래하는 유기물을 이용하여 철이온환원세균이 생장할 수 있으며, SRB와 methanogen의 생장은 철이온환원세균에 의해 방해를 받는다는 것을 나타낸다. Sediments collected from the Jungnang-cheon and its tributaries were used to enumerate anaerobic bacteria by most probable number (MPN) methods. A simple method was developed to detect ferrous ion in the culture fluid in order to count the number of iron ion reducers, and sulfate-reducing bacteria (SRB) and methanogens were detected by the presence of FeS precipitate in the culture or methane in the head space, respectively. The numbers of iron reducer was in the range of 10^7~10^8/g in the sediment of the stream containing higher organic content than the tributaries. The sediments of tributaries were analyzed to contain iron reducers less than 10^7 cells/g. With one exception the numbers of SRB and methanogens were less than 10^3 cells/g in the sediment. From these results it is concluded that organics in the sediment support the growth of iron reducers, which out-compete SRB and methanogens.

유전의 우성과 열성에 대한 중-고등학생과 교사의 오개념 분석

박시호,권영식,이길재 韓國敎員大學校 敎育硏究院 2009 敎員敎育 Vol.25 No.3

본 연구는 제7차 교육과정이 적용되고 있는 중학교 3학년,고등학교 3학년 그리고 교사를 대상으로 우성과 열성,불완전 우성,완전 우성,공우성에 대한 개념에서 나타나는 오개념을 알아보고자 하였다. 중학교 3학년 264명,고등학교 자연계열 3학년 학생 103명,생물 교사 53명의 응답을 분석하였다. 이 연구의 결과에 따르면,특히,학생과 교사 모두 우성은 '열성을 억제하고 표현되는 형질이다.' 열성에 대해 학생들은 '부모로부터 유전자를 전달받지 못하여 나타난다.’라는 오개념 비율이 높게 나타났다. 둘째,중학생의 24.4%, 고등학생의 19.4%가 '교배 결과 많이 출현하는 형질이 우성이다.’라는 오개념을 가지고 있었다. 셋째,중학생의 48.1%. 고등학생의 36.9%가 '열성은 생활에 불리하거나 우성이 우수한 형질이다.’라는 오개념을 가지고 있었다. 넷째,완전 우성,불완전 우성,공우성에 대해 교사와 학생 모두 높은 비율의 오개념을 가지고 있었다. 이 연구를 통해 교사는 교육을 실행하는 동안 '우성이 열성을 지배한다’ '억제한다’ '누른다’ 등의 표현은 사용하지 않는 것이 타당할 것으로 생각된다. 또한 개체 수준의 전달 유전과 분자 수준의 형질 발현과정을 통합하는 수업전략이 필요함을 알 수 있었다. The purpose of this study was to analyze the misconceptions of definition of dominance and recessive traits, law of dominance, incomplete dominance and codominance which middle and high school students and teachers have. For this purpose, we analyzed a questionnaire of 103 natural science students in the third grade and 264 middle school students in the third grade and 53 biology teachers. According to the results of analyzing the questionnaires, most of the students and teachers had various misconceptions on the concepts of dominance. Expecially, They had the misconception that 'dominance is controls completely recessive and then it is expressed' and the students about recessive characteristic shows because of gene isn't handed down from parents to progeny. Second, 24.4% of middle school students and 19.4% of high school students had the misconceptions many expressed trait is dominance. Third, 48.1% of middle school students and 36.9% of high school students had the misconceptions the recessive characteristic have a disadvantage in life or the dominance is predominance characteristics. Fourth, most of the students and teachers had very high misconceptions on complete dominance, incomplete dominance and codominance. According to this study, such expressions as 'dominant characteristics governs, controls, or suppresses recessive characteristics,' don't have to use in lessons of gene. Lessons for middle and high school students need to integrate transmission heredity at the object level and the process of characteristics expression at the molecular level.