• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 1999년도 제1회 학술대회논문집(KIASC 1st conference 99)
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• pp.153-156
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• 1999

In this paper, the inertance tube is modeled by the distributed impedance model. This model is verified by the analytical solutions for the long tube without the reservoir. In this model the distributed impedace effect of the inertance tube is included and mass flow rate and pressure distributions are calculated along the inertance tube for various inertance tube lengths. Mass flow rate at the inlet of the inertance tube is also calculated by this model and compared to the lumped impedance method. Mass flow rate by the distributed model shows quite different behaviors from the lumped model when the operating frequency is high and the length of the tube becomes large.

• 한국재료학회지
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• 제16권2호
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• pp.111-115
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• 2006

High-finned tubes have good thermal conductivity and have better cooling efficiency than plain tubes or low-fined tubes due to bigger air contact area. During high-fined tubes are manufactured by roll forming, the main technique is illustrated to optimizing primary material(copper pipe), optimized die matrix designing technique for roll forming, control manufacturing speed to develop productivity etc. In this study, a roll forming system was developed in oder to produce high-finned tube. Also a multi-step roll forming die was designed & built to produce high-finned tube that has over 10 mm fin height. And then, roll forming test using copper pipe was performed to produce high-finned tube. Roll forming process for producing highfinned tube was optimized by analyzing and adjusting misrostructure, hardness, and surface roughness of roll formed high-fined tube.

• 소성∙가공
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• 제9권6호
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• pp.631-637
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• 2000

The tube hydroforming technology is new key production technologies, which contribute to a light-weight cu. Because the tubes are used for hydroforming instead of the sheet materials formability test for tube is required to measure the formability of materials for hydroforming. In this Paper, a kind of formability test for tube, which can well represent the characteristics of tube hydroforming processes, is developed. Developed formability test method can consider not oかy the influence of material Properties but also contact with die and material. Some investigation was carried out to verify the effectiveness of developed formability test.

• 연구논문집
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• 통권24호
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• pp.27-39
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• 1994

lower vibration than in any other small refrigerators. The experimental results of three types of pulse tube refrigerators are presented in this paper. The objectives of this study are to develop the design technology of the double inlet pulse tube refrigerator and acquire its application method. As a preliminary experiment, the refrigeration performances of the basic, orifice and double inlet pulse tube refrigerator were investigated. The lowest temperature obtained in this experiment was 34.4K. The refrigeration capacity at the optimum operating condition of the double inlet pulse tube refrigerator was 23W at 80K.

• 대한지역사회영양학회지
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• 제3권3호
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• pp.430-439
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• 1998

This study was performed to investigate the nutritional status of neurosurgical tube-fed patients. The objective of this study was to improve the nutrition management of tube-fed patients. The current practices of tube feeding and enteral nutrition formula as for 95 patients in the hospital were examined by reviewing patients charts, and interviewing patients, nurses and their family members. The results are summarized as follows ; 57.9% of patients that received the formula showed a decrease in mental status. Among the subjects, 55.7% had nervous system diseases due to old age. Most of the tube-fed patients were hospitalized in the emergency room and while hospitalized, the status of their respiratory organ was abnormal. The method of tube-feeding was by Bolus injection and the type of the tube was a 16Fr size silicone tube. The amount of the injection per day while tube-feeding was on average 1424kcal for men and 1322kcal for women and the calories per day ranged from 1000-1500kcal(50.5%). The injection volume averaged 332.7ml and 45% of patients received more than 300ml per injection. The tube feeding intake rate was 127.9ml/min with 50% of subjects in the range of 50-100ml/min and 10% at 20ml/min. The longer the hospitalization, the older age, coma status, and the higher tube feeding rate, the more decreased were the biochemical parameters.

• 한국농공학회논문집
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• 제55권6호
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• pp.155-165
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• 2013

Recently, geotextile tube method can be widely applied to the river, costal and marine in the construction field, such as embankment, groin, breakwater, dyke structures and so on, in advanced countries of the world. And that has been constructed at the temporary road for incheon, ilsan-bridge construction and coast erosion protection in republic of korea. Geotextile tube is a tube shaped geotextile product and hydraulic pumping filled with dredged soils. In this paper, the numerical analysis was performed to investigate the behavior of geotextile tube with various properties of material character, shape condition, construction pressure and so on. Also, the field test was conducted in order to identify the construction ability of Samangum waterproof embankment using geotextile tube. According to the applied of field test, geotextile tube was 65 m long and 4.0 m diameter. Also, the permeability coefficient and ultimate tensile strength of geotextile tube is $1.6{\times}10^{-1}$ cm/sec and 205.26 kN/m, respectively. As a result of filed test, when filled, geotextile tube does not attain the same as its unfilled theoretical diameter, but may reach approximately of 55 percent of the theoretical diameter. At the time, geotextile tubes were 12.56 m in circumference and filled to a height of about 2.2 m. This paper presents case study on field application and behavior analysis of the saemangum waterproof embankment donggin 1 division construction using geotextile tube.

• Journal of Advanced Marine Engineering and Technology
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• 제36권5호
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• pp.618-626
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• 2012

Suppression of abnormal flow phenomena in the Francis hydro turbine is very important to improve the turbine performance. Especially, as cavitation and cavitation surge makes serious problems when the turbine is operated in the range of partial flow rate, optimum method of suppressing the abnormal flow characteristics is required necessarily. Moreover, as swirl flow in the draft tube of the Francis turbine decreases pressure at the inlet of the draft tube, suppression of the swirl flow can be an useful method of suppressing the occurrence of cavitation. In order to clarifying the possibility of suppressing the swirl flow by J-Groove in the draft tube, a series of CFD analysis has been conducted in the range of partial load, designed condition and excessive flow rate of a Francis turbine. A kind of J-Groove is designed and applied to the draft tube of the Francis hydro turbine model. The pressure contours, circumferential velocity vectors and vortex core regions in the draft tube are compared by the conditions with or without J-Groove. In addition, a group of data about the velocity in the draft is presented to show the influence of J-Groove.

• 대한기계학회논문집B
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• 제37권2호
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• pp.111-117
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• 2013

탄성튜브가 연결된 펌핑 챔버를 이용한 무밸브 펌프를 가상경계방법을 이용하여 수치적으로 연구하였다. 탄성 튜브와 펌핑 챔버 사이의 상호작용으로 인하여 무밸브 펌프 내의 유동이 생성되었으며, 탄성튜브의 스트레칭 계수, 벤딩 계수, 종횡비가 무밸브 펌프의 전체 유량에 미치는 영향을 살펴보았다. 펌프의 메커니즘을 이해하고자, 시간에 따른 탄성 튜브의 움직임과 그에 따른 유동 속도의 변화를 자세히 살펴보았으며, 탄성 튜브의 직경 크기와 펌프의 평균 유량 사이의 관계를 분석하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.373-378
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• 2003

It is important that overheat protection of super heated tube in boiler operation and maintenance. The overheat of super heat tube can make damage and rupture of tube material, which causes accidental shutdown of boiler. The super heated tube overheat is almost due to the lack of uniformity of gas temperature distribution. There are two ways to protect overheat of super heated tube. The one is to control hot gas operation pattern which is temperature or flow distribution. the other is to control super heated steam flow distribution. The former is difficult than the later, because of control device design. In this paper steam flow control method which uses orifices is proposed to protect overheat of super heat tube.

• 한국응급구조학회지
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• 제23권3호
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• pp.111-121
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• 2019

Purpose: Difficult organs or locations or inadequate tube intubations can cause complications. There are some cases in which the tube location changes or the tube is removed due to processing inside the organ while installing the stylet or rapid stylet removal. Thus, this study aimed to evaluate and develop an integrated intubation tube with stylet (IITS) for easier intubation of organs in emergency cases and reduce complications caused by the stylet. Methods: This study used a "Laerdal Airway Management Trainer". For stylet intubation, procedure No. 14 of the national practical test protocol was followed, but the removal step was omitted. In this study, each emergency case was intubated with an IITS, in which the stylet was not inserted or removed separately even though it has the function of an organ intubation stylet. Results: The existing classic ET intubation method had a success rate of 100% and had an average intubation time of 21.75 seconds, The developed IITS method was also successful in all cases and had an average intubation time of 15.78 seconds. Conclusion: Application of an IITS is expected to reduce intubation time and decrease inappropriate depth and intubation failure due to stylet removal, therefore improving the efficiency of airway maintenance.