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.

直交異方性 鋼床板의 設計 自動化에 關한 硏究

朴祥鎭,朴英錫,鄭時潤,鄭泰周 명지대학교 공학기술연구소 1992 공학기술연구소 논문집 Vol.7 No.-

Generally, an orthotropic steel plate deck bridge is called an "orthotropic bridge". The orthotropic bridge deck consists of thin steel plate stiffened longitudinal ribs at right angles to the floor beams. As the rigidities of the ribs and floor beams are generally of unequal magnitude, elastic behaviour is different in each of these two main directions. Because ribs and floor beams are orthogonal and because their elastic properties are different, the system became known as orthogonal-anisotropic, or, briefly, orthotropic. Mathematically, this elastic property is described by Hook's law. Further, we assume that it is homogeneous. Of all the methods considered in deck analysis, the most practical is that of Pelican and Esslinger. In this method, the deck system is a continuous orthotropic plate, rigidly supported by its main girders and elastically supported by the floor beam. The design of steel plate decks with open or closed ribs is made in two computation steps. In the first step, it is assumed that the floor beams are infinitely rigid. In the second step, the effects of the floor beam elasticity are considered. M"uller-Breslau Theory and 3 moment-equation are used to analyze the behaviour of the continuous beam on elastic and rigid supports. Many procedure are programmed in order to accomplish the economic design and accuracy.

노안수술후 각막형태검사 변화

박근성,고길환,김용선,이재림,민병무,최시환 충남대학교 의학연구소 2001 충남의대잡지 Vol.28 No.2

We prospectively analyzed the corneal topography of 26 eyes in 26 patients who had undergone scleral expansion for correcting presbyopia. We examined 26 eyes of 26 patients which were devided into 2 groups (mean age: 51 years, range 40-60 years) according to type of scleral expansion band, with computerized corneal topographic analysis system. Preoperatively and 5 times postoperatively (1day, 1week, 2weeks, 1month, 2months), quantitative descriptors of corneal topograpgy such as Sim K (simulated keratometry value), SRI(surface regularity index), and SAI(surface asymmetry index) were measured at each visit. The mean follow-up period was 43 days. Sim K of the operative eyes ranged from 0 to 2.5 (mean, 0.93) before operation, and mean 2.24 at postoperative 1 day in group Ⅰ. In group Ⅱ, Sim K was mean 2.20 at postoperative 1 day and decreased thereafter. SRI was from 0.54 to 1.39 and SAI was from 0.09 to 0.45 before operation. After operation, mean SAI was maximum at postoperative 2 week and mean SRI was maximum at postoperative 1 day and decreased thereafter. After two months, it became minimum. This study demonstrates that quantitative topographic change after scleral expansion for correcting presbyopia were great during first 1 week after surgery but this change diminished thereafter. Further long studies are in progress to evaluate the long term effects of this procedure.