• 한국포장학회지
• /
• 제20권2호
• /
• pp.35-39
• /
• 2014

최근 커피시장의 고속 성장과 더불어 커피 포장용 가스배출 밸브(Degassing valve)의 수요도 급격히 증가하고 있다. 가스배출 밸브 주요 제조사(Big maker)로 Goglio사(이탈리아), Bosch사(독일) 및 Wipf사(스위스)가 있는데, 이들이 전세계 가스배출 밸브 포장재 소비량의 80%이상을 공급하고 있다. 국내시장 역시 대부분 수입에 의존하고 있어 수입 대체와 국내 포장산업 활성화를 위해 기술적 차별화와 동시에 선진기업 수준의 품질 성능을 갖춘 가스배출 밸브의 개발이 필요하였다. 따라서, 본 연구에서는 링타입 고무막을 적용하여 중앙 개폐형 가스배출 밸브(SP 밸브)를 개발하였으며, 실험을 통해 열림압력 820~1200 Pa, 닫힘압력 10~50 Pa, 가스 유동율 1.2~1.6 L/min로 Goglio 밸브와 대등한 수준의 품질 성능을 확인할 수 있었다. 또한, 식품용 기구 및 용기 포장 공전에 따른 밸브의 식품용기 품질 적합성을 확인하였으며, 향후 커피 포장용 밸브의 국내외 시장 점유율 확대와 함께 국내 발효식품 포장에 적용함으로써 한식 세계화에 기여할 것으로 기대된다.

• Journal of Chest Surgery
• /
• 제16권4호
• /
• pp.498-505
• /
• 1983

It has been over 20 years since successful operations of Cardiac valves at the Department of Thoracic and Cardiovascular surgery, college of medicine, Yonsei University. About six hundreds of patients with severely symptomatic valvular heart disease have had valve operations with complete loss or sharp decrease in their cardiac symptoms since 1956. As the number of cardiac patient increases, reoperation on valves assumes greater importance. To define the group of patients undergoing reoperations on valves and the factors influencing their survival, we have reviewed our experiences of the reoperation on valves at the Yonsei University, Severance Hospital. This is a report of 29 cases which was undergone secondary or more surgery for valvular heart disease from 1966 to 1983. The primary operations includes 159 cases of open heart surgery from 1966 to 1975 and 476 cases from 1976 to march, 1983. The secondary operations are classified into groups of secondary valvuloplasty or valvotomy [8 cases], prosthetic valve replacement following valvuloplasty or valvotomy [14 cases] and prosthetic valve rereplacement [2 case] for such as calcification, degeneration and perforation of the cusps and paravalvular leakage, of the bioprosthetic valves. The leading indication for reoperation of mitral valve was restenosis or stenoinsufficiency, The indications of aortic valve replacement was active bacterial endocarditis, medically uncontrollable prosthetic endocarditis or paravalvular leakage. Overall death rate of the reoperation was 17.4% [5 death among the 29 patients] and the leading causes of death were myocardial failure, arrhythmia, cerebral embolism, acute renal failure due to low output syndrome. And it was followed by sepsis associated with active prosthetic endocarditis. The death rate of reoperation was 4.3% in the elective cases except urgent cases and the death rate of overall cardiac valve except reoperation cases was 4.1% in the last two years. Although the general mortality of reoperation was high, both mortality rates were comparable except emergency cases due to urgent preoperative patient’s condition.

• 한국수자원학회논문집
• /
• 제38권7호
• /
• pp.585-593
• /
• 2005

최근의 상수관망의 안전도 확보, 부가적 용수공급로 확보, 그리고 관(管)내 배수를 위한 부분적인 상수관망의 격리문제가 대두 되면서 이를 위한 밸브역할의 중요성이 인식되고 있다. 기본적인 상수관망에서의 밸브역할은 물의 흐름과 압력조절 그리고 관 파괴와 오염물 확산시 부분적 관의 격리라고 할 수 있다. 이중 본 논문에서는 관의 격리 기능을 중심으로 밸브를 해석한다. 관의 파괴로 인한 부분적인 상수관망의 격리시에 일반적으로 그 관만이 아닌 주변의 다른 관들도 함께 격리가 될 수 있으며 이것은 격리하고자하는 관에 설치된 밸브배치에 따라 달라진다. 본 논문에서는 밸브의 배치에 따라 함께 격리되는 관들을 하나의 단위로 보며 이것을 "Segment"라 부른다. Segment에 따라 실제 격리되는 관의 범위가 주어지며 이것에 따라 전체 상수관망을 나눈 후 각 밸브의 중요도와 상수관망의 효율성 평가에 이용한다. 효율성 평가를 위해 7개의 효율성 지수를 제안하며 실제 상수관망에 적용하여 사용성을 검증한다.

• 설비공학논문집
• /
• 제19권3호
• /
• pp.269-274
• /
• 2007

A 3-way valve has been applied to a distributor in a hot-water heating system and the performance of the system was evaluated in view of the variations of pressure drop and flow rate. The 3-way valve has been designed to bypass overplus hot-water when a control valve is closed. Note that the flow goes through heating pipeline in normal operation. In the present study, the measured pressure drops in each part of the flow paths show that the contribution to the total pressure drop is in the order of the supply header with control valves, piping system of each room and return header of the distributor, even though the amount of it is different according to the flow paths. As a result of performance test by sequential closing of the control valves, the variations of pressure drop and flow rate in the distributor with 3-way valves is much lower than those with previous 2-way valves, which prevent noises induced by pressure fluctuations.

• 한국자기학회지
• /
• 제18권6호
• /
• pp.227-231
• /
• 2008

Zr 함량에 따르는 CoFeZr의 합금박막의 구조 및 자기적 특성, 그리고 비정질 CoFeZr을 사용한 스핀밸브의 자기저항 및 열적 안정성에 관하여 연구하였다. Zr 조성이 증가함에 따라 CoFeZr 합금 박막의 포화자기장 및 보자력은 감소하며 완전히 비정질이 형성되었을때 보자력은 최소 값을 보였다. Zr의 함량이 약 18 at% 이상일 때 완전한 비정질이 형성되었다. 비정질 CoFeZr을 스핀밸브에 적용하였을 때 기존의 CoFe을 사용한 스핀밸브보다 자기저항비와 교환결합력은 약간 감소하는 경향을 확인 하였다. 이는 비정질 자성체의 상대적으로 높은 저항값에 기인하였다. 그러나 ${\Delta}{\rho}$, 즉 스핀의존산란은 향상되었다.

• Nuclear Engineering and Technology
• /
• 제52권10호
• /
• pp.2173-2182
• /
• 2020

Control valves are widely used to regulate fluid flux in nuclear power plants, and there are more than 1500 control valves in the primary circuit of one nuclear power plant. With their help, the flux can be regulated to a specific level of water or steam to guarantee the energy efficiency and safety of the nuclear power plant. The flux characteristics of the control valve mainly depend on the valve core shape. In order to analyze the effects of valve core shapes on flux characteristics of control valves, this paper focuses on the valve core shapes. To begin with, numerical models of different valve core shapes are established, and results are compared with the ideal flux characteristics curve for the purpose of validation. Meanwhile, the flow fields corresponding to different valve core shapes are investigated. Moreover, relationships between the valve core opening and the outlet flux under different valve core shapes are carried out. The flux characteristics curve and equation are proposed to predict the outlet flux under different valve core openings. This work can benefit the further research of the flux control and the optimization of the valve core for control valves in nuclear power plants.

• 상하수도학회지
• /
• 제36권5호
• /
• pp.261-273
• /
• 2022

In this study, we collect water control valves that have had accidents due to existing cracks, etc. are collected, and propose investigation items for strengthening the valve structural safety evaluation through a series of analyzes from valve specifications to physicochemical properties are proposed. The results of this study are as follows. First, there was a large variation in the thickness of the body or flange of the valves to be investigated, which is considered to be very important factor, because it may affect the safety of the valve body against internal pressure and the flange connected with the bolt nut. Second, 60% of the valves under investigation had many voids in the valve body and flange, etc. and the decrease in thickness due to corrosion was relatively large on the inner surface in contact with water rather than the outer surface. It is judged that the investigation of depth included voids is very important factor. Third, all valves to be investigated are made of gray cast iron foam, and therefore it is judged that there is no major problem in chemical composition. It is judged that the chemical composition should be investigated. Fourth, as a physical investigation item, the analysis of metal morphology structure seems to be a very important factor for nodular cast iron from rather than a gray cast iron foam water valve with a flake structure. As it was found to be 46.7~68.8% of the standard recommended by KS, it could have a direct effect on damage such as cracks, and therefore it is judged that the evaluation of tensile strength is very important in evaluating the safety of the valve.

• Journal of Chest Surgery
• /
• 제31권12호
• /
• pp.1183-1194
• /
• 1998

배경: 인제 대학교 의과대학 부산 백병원 흉부외과학 교실에서는 1985년 9월부터 1997년 9월까지 총 2,000례의 개심술을 시행하였다. 대상 및 방법: 전체 2,000례의 개심술 중 선천성 심질환이 1532례, 후천성 심질환이 468례였다. 연령별 분포는 선천성 심질환에서는 생후 9일에서 68세 까지였고, 후천성 심질환에서는 11세부터 66세 까지였다. 결과: 선천성 심질환군은 심실중격 결손증(VSD)이 940례, 심방중격 결손증(ASD)이 324례, 팔로 4징증(TOF)이 112례, 폐동맥 협착(PS)이 46례, 심내막상 결손(ECD)이 38례, 발살바동 파열(Valsalva sinus rupture)이 15례, 완전 대혈관 전위증(TGA) 과 양대혈관 우심실 기시증(DORV) 각각 4례 등으로 구성되었다. 선천성 심질환군에서는 근치적 수술후 3.1%의 사망률을 보였다. 후천성 심질환군 468례 중 심장 판막질환이 381례, 허혈성 심질환이 48례, 심장종양이 12례, Annuloaortic ectasia가 8례, 박리성 대동맥류가 16례 등이었다. 381례의 판막질환 중 단일 판막 치환술이 226례(대동맥 판막 치환술 36례, 승모판막 치환술 188례, 삼첨판막 치환술 2례), 이중 판막 치환술이 71례(대동맥 판막 치환술 과 승모판막 치환술), 승모판막 치환술과 삼첨판막 성형술을 동시에 시행한 경우가 54례, 이중 판막치환술과 삼첨판막 성형술을 동시에 시행한 경우가 18례 등이었다. 사용된 인공판막은 총 466개 였다. 승모판막 치환술에 사용된 인공판막은 St. Jude Medical 판막이 123개, Carpentier-Edwrads 판막이 90개, CarboMedics 판막이 65개, Sorin 판막이 42개, 기타 판막이 16개였다. 대동맥 판막 치환술에 사용된 인공 판막은 St. Jude Medical 판막이 68개, CarboMedics 판막이 36개, Carpentier-Edwards 판막이 14개, 기타 판막이 9개 였다. 관상동맥 우회술(CABG)은 48례에서 시행되었다. 혈관 이식편의 수는 단일 혈관 이식이 14례, 이중 혈관 이식이 21례, 삼중 혈관 이식이 10례, 사중 혈관 이식이 3례였다. 결론: 술후 재원 기간내 사망률은 비청색증 선천성 심질환에서 2.0%, 청색증 선천성 심질환에서 15.5%, 후천성 심질환에서 5.1%였다. 전체 사망률은 2,000례 중 72명이 사망하여 3.6%였다

• KIEE International Transactions on Electrophysics and Applications
• /
• 제4C권4호
• /
• pp.155-159
• /
• 2004

This work reports the theoretical and experimental investigations of capillary bust valves to regulate liquid flow in microchannels. The theoretical analysis uses the Young-Laplace equation and geometrical considerations to predict the pressure at the edge of the valve opening. Numerical simulations are employed to calculate the meniscus shape evolution while the interface is pinned at the valve edge. Microchannels and valves are fabricated using soft lithography. A wafer-rotating system, which can adjust the driving pressure by rotational speed, induces a liquid flow. Experimentally measured valve-bursting pressure agrees with theoretical predictions.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.3056-3061
• /
• 2007

The technology of AC solenoid valves is now considered as a core technology in the fields of the production line of semi-conductor chips and the micro fluid chips for medical applications. And AC solenoid valves, which operate by compressed air, are characterized by high speed response, great repeatability and that the pressure on the cross sectional area of poppet is kept constant regardless of the fluctuation of the pressure exerted on the ports. In this study, AC solenoid valves that posses the high-speed responsibility and the high rate of flow have designed and analyzed through the law of equivalent magnetic circuit and Finite Element Method (FEM) respectively. In case of poppet, Flow field characteristic was analyzed by the variation of poppet and it was able to display flow field by changing the location of the poppet. Also, we verified possibility of the design through the static and dynamic pressure and the 3D distribution curve of the force by working the front poppet.