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내접형 기어펌프용 로터의 소음저감을 위한 치형 최적설계
배준호(Jun Ho Bae),배원병(Won Byong Bae),주웅탁(Ung Tak Joo),김철(Chul Kim) 대한기계학회 2014 大韓機械學會論文集A Vol.38 No.3
내접형 기어펌프의 경우 내구성과 소형화의 장점을 가지고 있으나, 유량증대 및 소음저감의 성능 개선이 요구되고 있다. 본 논문에서는 외부로브 형상이 다양한 곡선 조합(타원 1-인볼루트-타원 2)인 경우에 대하여 기구학적 치형 형상 관계식을 유도하고, 창성된 치형에 대해 소음에 관계된 성능인자(압력각, 유량맥동과 미끄럼률)를 예측하여 소음정도를 수치적으로 비교하였다. 또한 이론 해석을 통해 구한 치형형상과 성능인자 예측 알고리즘을 통하여 설계변수와 성능인자간의 영향도를 분석하였고, 분석 결과를 바탕으로 일정한 유량성능을 유지하면서 소음이 저감된 치형의 최적설계를 수행하였다. 해석결과를 바탕으로 제시된 치형의 최적설계에 대한 시제품 제작 및 소음 시험을 통해 설계의 타당성을 검증하였다. An internal gear pump is required to improve the flow rate and noise. Furthermore, such pumps are durable and small in size. In this study, equations of the rotor shape with multiple profiles (ellipse 1-involute-ellipse 2) were derived, and relevant performance parameters (pressure angle, irregularity, and specific sliding) of the internal gear pump to noise were predicted and compared. Rotor profiles and performance parameters were obtained by a prediction algorithm for theoretical analysis, and the effects between the design parameters and the performance parameters were analyzed. Based on the analysis results of the effects, an optimal design of the rotor profile was proposed, and a noise test of the prototype was performed to evaluate the reliability of the design.
아르곤 플라스마 응고소작술 (argon plasma coagulation)로 치료한 위전정부 혈관확장증 (gastric antral vascular ectasia) 1예
배용목,정을조,허정,김광하,주형준,강대환,조몽,양웅석,이창훈 대한내과학회 2002 대한내과학회지 Vol.63 No.1
Gastric antral vascular ectasia (GAVE) is a rare but important cause of chronic gastrointestinal bleeding. Endoscopically, it has characteristic thickened red vascular folds radiating from the pylorus to the antrum. Diagnosis is made primarily by endoscopy. Histologic examination of the endoscopic mucosal biopsies may confirm the endoscopic diagnosis. Many treatment modalities of the gastric antral vascular ectasia exist. One of them, the argon plasma coagulation (APC) is an excellent therapeutic tool. Inactive argon gas is converted to ionized form by means of electrical energy. Ionized argon plasma conducts high frequency electrical energy to tissues and leads coagulation necrosis of tissues. We experienced a case of gastric antral vascular ectasia presenting melena for about one month in a 72-year-old man treated endoscopically in four sessions with argon plasma coagulation.
Ki Ung Kang(강기웅),Jun Young Oh(오준영),Yun Ha Lee(이윤한),Hye Sun Lee(이혜선),Seo Yeon Jin(진서연),Sun Sik Bae(배순식) 한국생명과학회 2018 생명과학회지 Vol.28 No.12
죽상동맥경화는 대동맥의 만성염증에 의해 주로 발병되는 폐쇄동맥질환이다. 혈관평활근세포의 증식 및 이동은 죽상동맥경화 발병의 주된 병리적 반응이다. 본 연구에서는 죽상동맥경화 발병기전을 유도하는 표적 염증반응물질의 탐색 및 이들에 의한 신호전달 기전을 연구하였다. 혈관평활근세포의 증식 및 이동은 prostaglandin F2α (PGF2α)에 의해 의미 있게 증가하였으나 tumor necrosis factor α (TNFα)에 의해서는 증가하지 않았다. Prostacyclin I₂ (PGI₂)는 혈관평활근세포의 증식은 촉진시켰으나 이동은 오히려 억제하였다. prostaglandin D₂ (PGD2) 및 prostaglandin E₂ (PGE₂)는 혈관평활근세포의 증식을 촉진시켰으나 이동에는 영향을 미치지 않았다. PGF2α는 용량 의존적으로 혈관평활근세포의 증식 및 이동을 촉진시켰고 EC50는 약 0.1 μM로 관찰되었다. 혈관평활근세포에서 phospholipase C-β3 (PLC-β3) 아형의 발현은 매우 높았으나 PLC-β1, PLC-β2, 및 PLC-β4의 발현은 관찰되지 않았다. U73122 처리를 통해 PLC의 활성을 억제하면 PGF2α에 의한 혈관평활근세포의 이동이 억제되었다. 또한 PLC-β3의 발현을 억제하면 PGF2α에 의한 혈관평활근세포의 증식 및 이동이 억제되었다. 이러한 결과들을 바탕으로 PGF2α 는 혈관평활근세포의 증식 및 이동에 중요한 역할을 수행하고, 여기에는 PLC-β3가 필수적인 역할을 담당하고 있음을 제안한다. Atherosclerosis is an obstructive vessel disease mainly caused by chronic arterial inflammation to which the proliferation and migration of vascular smooth muscle cells (VSMCs) is the main pathological response. In the present study, the primary responsible inflammatory cytokine and its signaling pathway was investigated. The proliferation and migration of VSMCs was significantly enhanced by the prostaglandin F2α (PGF2α), while neither was affected by tumor necrosis factor α. Prostacyclin I₂ was seen to enhance the proliferation of VSMCs while simultaneously suppressing their migration. Both prostaglandin D₂ and prostaglandin E₂ significantly enhanced the migration of VSMCs, however, proliferation was not affected by either of them. The proliferation and migration of VSMCs stimulated by PGF2α progressed in a dose-dependent manner; the EC50 value of both proliferation and migration was 0.1 μM. VSMCs highly expressed the phospholipase isoform C-β3 (PLC-β3) while others such as PLC-β1, PLC-β2, and PLC-β4 were not expressed. Inhibition of the PLCs by U73122 completely blocked the PGF2α-induced migration of VSMCs, and, in addition, silencing PLC-β3 significantly diminished the PGF2α-induced proliferation and migration of VSMCs. Given these results, we suggest that PGF2α plays a crucial role in the proliferation and migration of VSMCs, and activation of PLC-β3 could be involved in their PGF2α-dependent migration.
Jeon, Ung Bae,Chung, Jin Wook,Jae, Hwan Jun,Kim, Hyo-Cheol,Kim, Sang Joon,Ha, Jongwon,Park, Jae Hyung American Roentgen Ray Society, etc.] 2010 American Journal of Roentgenology Vol.195 No.3
<P>OBJECTIVE: The purpose of this study was to use CT venography to evaluate long-term patency and changes in the iliac veins after stent placement for acute iliofemoral vein thrombosis due to May-Thurner syndrome. MATERIALS AND METHODS: From December 1999 to July 2007, 30 patients (22 women, eight men; age range, 30-78 years; mean, 56.7 years) with acute iliofemoral vein thrombosis due to May-Thurner syndrome diagnosed with CT venography were treated with catheter-directed thrombolysis and stent placement. The patients underwent follow-up CT venography at variable intervals according to clinician discretion. The primary objective was to determine the primary patency of the stented segment. The secondary objective was to investigate the potential role of CT venography by analyzing the morphologic features and interval changes in stented iliac veins. Cumulative primary and secondary stent patency rates were calculated by Kaplan-Meier estimation. RESULTS: Four stent occlusions and one stent collapse were found at the first follow-up CT venographic examination within 1 year (mean duration, 129.3 days) after treatment. One stent occlusion and one stent collapse were managed successfully. The primary and secondary patency rates were 83.3% and 90% 1 and 5 years after treatment. The morphologic features of the common iliac vein did not affect stent patency or expanded stent diameter. During sequential CT venographic follow-up, no new in-stent stenosis or occlusion was found. CONCLUSION: Iliac stents placed for May-Thurner syndrome with acute thrombosis had excellent long-term patency. Restenosis or occlusion occurred early, and initial luminal patency was well maintained during long-term follow-up.</P>
콘크리트 궤도용 레일체결장치의 종방향 마찰거동에 대한 통계적 특성
배현웅(Bae, Hyun-Ung),박상준(Park, Sang-Jun),윤경민(Yun, Kyung-Min),박범호(Park, Beom-Ho),임남형(Lim, Nam-Hyoung) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.11
장대레일 궤도가 철도교량 상에 위치하는 경우, 교량과 궤도의 상호작용에 의해 레일에 발생하는 축력분포가 복잡해 지며 부가축력이 발생하여 토노반상 장대레일에 비해 큰 축력이 레일에 발생된다. 이로 인해 교량상에 부설되는 궤도는 교량 과의 상호작용 영향을 최소화하여 궤도와 주행열차의 안전성을 추가로 확보하여야 한다. 국내 철도설계지침 및 편람 KR C-08080(궤도-교량 종방향 상호작용 해석)에서는 상호작용의 주요 변수인 레일체결장치의 종방향 저항(마찰거동) 물성치가 유럽기준을 적용하여 특정 수치로 규정되어 있으나, 국내 철도에 적용하기 위해서는 실제 사용되는 체결장치의 성능 특성을 반영한 검토가 필요하다. 본 논문에서는 국내 교량상 콘크리트 궤도에 적용되는 레일체결장치의 마찰거동 실험을 수행하였 으며, 이로부터 체결장치의 물성치에 대한 통계적 특성을 분석하였다. In the case of CWR (Continuous welded rail) located on the railway bridge, the CWR has additional axial force due to interaction of bridge and track. Therefore, the CWR tracks located on the bridge have to secure the safety of running train and CWR track through mitigating influence for interaction of bridge and track. The railway design guide in Korea (KR C-08080) provides a certain value for property of longitudinal friction behavior of rail fastening system that is major parameter of interaction behavior by applying European codes. However, in order to apply to domestic railway, it is necessary to review property characteristics of the rail fastening system in actual use. In this paper, the experiment for longitudinal friction behavior of rail fastener applied to concrete track on the railway bridge in Korea was carried out, and statistical characteristic for property of the rail fastener was analyzed from the result of the experiment.
Jeon, Ung Bae,Lee, Jun Woo,Choo, Ki Seok,Kim, Chang Won,Kim, Suk,Lee, Tae Hong,Jeong, Yeon Joo,Kang, Dae Hwan WJG Press 2009 WORLD JOURNAL OF GASTROENTEROLOGY Vol.15 No.46
<P>To evaluate the utility of assessing iodized oil uptake with cone-beam computed tomography (CT) in transarterial chemoembolization (TACE) for small hepatocellular carcinoma (HCC).</P>