선천성 사엽성 반월형 판막 −1예 보고−

서민범,서홍주 대한흉부외과학회 2009 Journal of Chest Surgery (J Chest Surg) Vol.42 No.3

A 17-year-old male patient was referred with symptoms of dyspnea. Multi-detector computerized tomography (MDCT) and echocardiography evaluation revealed quadricuspid aortic and pulmonary valves, an atrial septal defect (ASD), and pulmonary stenosis. We closed the ASD using a bovine patch and performed a commissurotomy of the pulmonary valve. Quadricuspid semilunar valves are very rare congenital abnormalities that are reported to occur nine times more frequently in the pulmonic valve than in the aortic valve. According to the Hurwitz and Roberts classification, the aortic valve was type A, and the pulmonic valve was type B. The aortic valve had normal function, but the pulmonic valve was stenotic and had abnormal function. 호흡곤란을 주소로 내원한 17세 환자가 대동맥 및 폐동맥 사엽성 판막을 보이며 심방중격결손과 폐동맥 판막 협착증이 발견되어 소심막을 이용한 심방중격결손 봉합 및 폐동맥 판막 교련절개술을 시행하였다. 대동맥 판막과 폐동맥 판막이 모두 사엽성 판막을 보이는 경우는 매우 드문 선천성 기형으로 폐동맥 사엽성 판막이 대동맥 사엽성 판막보다 9배정도 많다. 본 증례는 Hurwitz and Roberts 분류법상 대동맥판막은 A형, 폐동맥판막은 B형이었으며 대동맥 판막기능은 정상적이었고 폐동맥 판막 협착증을 보였다.

Study on the Diagnosis of Abnormal Prosthetic Valve

이혁수,Lee, Hyuk-Soo The Korea Institute of Convergence Signal Processi 2013 융합신호처리학회 논문지 (JISPS) Vol.14 No.1

The two major problems related to the blood flow in replaced prosthetic heart valve are thrombus formation and hemolysis. Reliability of prosthetic valve is very important because its failure means the death of patient. There are many factors affecting the valvular failures and their representatives are mechanical failure and thrombosis, so early noninvasive detection is essentially required. The purpose of this study is to detect the various thromboses formation by using acoustic signal acquisition and its spectral analysis on the frequency domain. We made the thrombosis models using Polydimethylsiloxane (PDMS) and they are thrombosis model on the disc, around the sewing ring and fibrous tissue growth across the orifice of valve. Using microphone and amplifier, we measured the acoustic signal from the prosthetic valve, which is attached to the pulsatile mock circulation system. A/D converter sampled the acoustic signal and the spectral analysis is the main algorithm for obtaining spectrum. Then the spectrum of normal and 5 different kinds of abnormal valve were obtained. Each spectrum waveform shows a primary and secondary peak. The secondary peak changes according to the thrombus model. To quantitatively distinguish the frequency peak of the normal valve from that of the thrombosed valves, analysis using a neural network was employed. Acoustic measurement has been used as a noninvasive diagnostic tool and is thought to be a good method for detecting possible mechanical failure or thrombus.

흡ㆍ배기 밸브의 밀착이상이 엔진연소특성에 미치는 영향

손성만(Sung Man Son),박경석(Kyoung Suk Park) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.3

The unbalance of the power output, noise, and vibration is happened by the disproportionate pressure variation in the cylinder. For this reason, decrease of the pressure in the cylinder and increase of the residual gas effect on the engine performance. If the abnormal combustion is continued, the crack would be occurred in the engine block. And it could be broken down. For the normal combustion of the SI engine, it is important to supply the balanced mixture by each operating condition. In this study, it was tested the combustion characteristics in the cylinder according to the abnormal adjusting of intake & exhaust valve. This test is willing to set a basic data's analysis for developing an automotive diagnosis system by analyzing the pressure in the cylinder, the output signal of MAP sensor, the exhaust gas, etc.

비정상 물공급 시나리오를 고려한 상수도관망 최적 밸브위치 결정

이승엽,정동휘 한국수자원학회 2019 한국수자원학회논문집 Vol.52 No.10

Valve in water distribution network (WDN), that controls the flow in pipes, is used to isolate a segment (a part of WDN) under abnormal water supply conditions (e.g., pipe breakage, water quality failure event). The segment isolation degrades pressure and water serviceability in neighboring area during the water service outage of the segment. Recent hydraulic and water quality failure events reported encouraging WDN valve installation based on various abnormal water supply scenarios. This study introduces a scenario-based optimal valve installation approach to optimize the number of valves, the amount of undelivered water, and a shortest water supply path indicator (i.e., Hydraulic Geodesic Index). The proposed approach is demonstrated in the valve installation of Pescara network, and the optimal valve sets are obtained under multiple scenarios and compared to the existing valve set. Pressure-driven analysis (PDA) scheme is used for a network hydraulic simulation. The optimal valve set derived from the proposed method has 19 fewer valves than the existing valve set in the network and the amount of undelivered water was also lower for the optimal valve set. Reducing the reservoir head requires a greater number of valves to achieve the similar functionality of the WDN with the optimal valve set of the original reservoir head. This study also compared the results of demand-driven analysis (DDA) and the PDA and confirmed that the latter is required for optimal valve installation. 상수도 관망 밸브는 평상시 관로의 유향을 변경하는 역할을 하지만, 관로 파손, 수질 문제 등 사고 발생 시 해당 구역을 격리하는데에도 이용된다. 밸브 조작에 의한 구역 단수는 주변 지역의 압력 및 물 공급 성능 저하를 유발한다. 최근 안정적인 상수도 관망 물 공급을 위협하는 사고가 다양하고 빈번하게 발생하고 있으며, 이에 따라 다양한 시나리오를 고려하여 밸브 위치 결정을 하는 것이 필요하다고 할 수 있다. 따라서 본 연구에서는 밸브의 개수, 구역 격리 시 물 부족량, 수리학적 거리 인자(Hydraulic Geodesic Index, HGI)를 통합한 목적함수를 개발하고, 다양한 물 부족 시나리오에 기반한 밸브 최적 위치 결정 방법론을 제안한다. 제안한 방법론은 페스카라 관망에 적용되었으며, 시나리오별로 도출된 최적 밸브 설계안의 차이점을 분석하였다. 최적 밸브 위치 탐색 과정 중 수행된 관망 수리해석은 압력 기반(Pressure Driven Analysis, PDA)으로 수행하였다. 개발된 방법론으로 도출한 최적 밸브 설계안은 기존 설계안 대비 밸브 개수가 최대 19개나 적었고, 세그먼트 격리 시 물 공급 부족량 또한 상대적으로 작았다. 수원 수두가 낮은 시나리오를 고려할수록 더 많은 밸브가 설치되었는데, 밸브 추가 설치에 따른 비용증가는 다양한 시나리오에서 물 공급 성능 향상으로 이어짐을 확인하였다. 또한, 세그먼트 격리 상황 모의를 압력 및 유량 기반 해석으로 수행한 결과를 비교하여, 밸브 최적 위치 설계 수행 시 압력 기반 해석이 필요함을 확인하였다.

박용 중속 디젤 엔진 밸브트레인의 이상 소음 원인 규명

김원현(Won Hyun Kim),김훈석(Hoon Suk Kim),이수목(Soo Mok Lee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

An abnormal noise was detected in the valve train of newly developed medium speed diesel engine during the shop test. The valve train system and cam profiles were designed based on the kinetic and kinematic analyses. And the vibration characteristics of camshaft were also considered. Nevertheless, the impulse noise was generated and it was confirmed that this is due to the crashing of intake valve in closing timing at the initial test. To investigate the root causes, the dynamic behaviors of valve train system and the torsional vibration of camshaft were measured. From these experiments and the additional analysis, it was concluded that the one of the cause of crashing is coincidence of intake valve closing timing and the fuel cam timing. The other one is the maximum acceleration of intake cam which close to maximum operating speed of valve train. In this work, the intake cam profile was modified to reduce the maximum valve acceleration and then the abnormal noise was disappeared.

HIPPS Valve 구동 시스템 운전 전산 모사

배징도(JingDo BAE),최주형(JooHyung CHOI),김정환(JeongHwan KIM),김도형(DoHyung KIM),오세준(SeJoon OH) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11

HIPPS(High Integrity Pressure Protection System) is installed in front of major equipment of plant system including offshore plant such as separator to prevent failure and accident caused by abnormal pressure. This is a pressure control safety system that replaced ESDV(Emergency Shutdown Valve) and EVV(Emergency Venting Valve) and guarantees high stability. If abnormal pressure is detected on the sensors installed in front of the major equipment, the system should close the valve within the minimum required time. In this study, the operation of driving part for HIPPS is visualized by simulating to improve understanding for the behavior of HIPPS when abnormal pressure is detected.

이상 고수온에 반응하는 이매패류 참굴(Crassostrea gigas)의 패각운동을 활용한 생물모니터링시스템 연구

문수연,오석진,김대현,윤양호 해양환경안전학회 2017 海洋環境安全學會誌 Vol.23 No.1

이상 고수온을 감지하기 위한 생물모니터링 시스템(BMS) 연구를 위해, 4단계의 수온(5, 10, 20와 30℃)에서 참굴 패각운동을 측정하였다. 모든 참굴은 실험시작 전에 3일 동안 절식을 통하여, 먹이섭이 및 배출에 따른 패각운동의 요인을 제거하였다. 5℃ 실험구에서는 패각운동이 관찰되지 않았지만, 수온의 증가와 함께 패각운동은 증가하였다(10℃ : 6.31±2.18 times/hr, 20℃ : 22.0±10.0 times/hr). 30℃에서는 5℃와 같이 패각운동이 전혀 보이지 않았던 실험구와 20℃와 유사한 패각운동이 실험구가 나타났다. 이는 30℃ 이상에서도 20℃와 같은 신진대사를 보이는 개체군이 있었으나, 대부분이 신진대사의 활력의 감소에 기인하여 폐각상태가 지속되는 것으로 나타났다. 따라서 참굴 양식장에 고수온 감지를 위한 참굴 패각운동 BMS를 설치한다면, 경계단계는 빠른 패각운동(약 30.0회/hr 이상)일 때, 심각단계는 수시간 이상 폐각상태일 때, 조기경보(early warning)를 내릴 수 있을 것이다. 따라서 참굴 패각운동을 활용한 BMS는 이상고수온의 조기경보에 대하여 효과적으로 활용이 가능할 것으로 판단된다. This study contains research on a bio-monitoring system (BMS) capable of detecting abnormal high water temperatures, the shell valve movements (SVMs) of Pacific oysters (Crassostrea gigas), which were measured at four different temperature (5, 10, 20 and 30℃) under laboratory conditions. All the Pacific oysters were kept under fasting conditions for 3 days to prevent the influence of food and excretions before the onset of the experiments. SVMs did not detect at 5℃. However, SVMs increased with an increase in temperature (at 10℃ : 6.31±2.18 times/hr and at 20℃ : 22.0±10.0 times/hr). At 30℃, SVMs were divided into two groups: those with no SVMs as at 5℃ and those with SVMs similar to conditions at 20℃ (23.9±9.35 times/hr). This indicates oyster shells maintain a closed condition due to a decrease in metabolism at 30℃, although some Pacific oysters had active SVMs due to an increase in metabolism. If a BMS using the SVM status of Pacific oysters was installed to monitor abnormal high water around oyster farms, early warning levels and serious alerts might be made available more rapidly for SVMs of more than ca. 30 times/hr and closing conditions in a matter of hours, respectively. Therefore, a BMS using the SVMs of Pacific oysters might be an effective early warning system for abnormal high water temperatures.

비후성 심근증의 임상적 관찰

배호상,곽동훈,박의현 慶北大學校 醫科大學 1998 慶北醫大雜誌 Vol.39 No.2

CT Findings of Quadricuspid Pulmonary Valve with Pulmonary Artery Aneurysm

이규정,용환석,이재욱,강은영 대한영상의학회 2018 대한영상의학회지 Vol.79 No.2

Quadricuspid pulmonary valve (QPV) with pulmonary artery aneurysm is an uncommon condition. QPV is typically clinically silent, so it is often diagnosed after death. However, recent advancements in imaging modalities, such as computed tomography (CT), have allowed more frequent incidental diagnosis of QPV in living adults. We report a case of QPV with pulmonary artery aneurysm in an asymptomatic adult; the condition was detected by CT aortography but was not discernible in echocardiography. Following the case presentation, we review the prior related literature.

디젤발전기 엔진 상태 진단 기술의 발전소 적용 연구

최광희(Kwang-Hee Choi),이상국(Sang-Guk Lee) 한국동력기계공학회 2013 동력시스템공학회지 Vol.17 No.4