• Journal of Advanced Marine Engineering and Technology
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• 제15권5호
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• pp.47-54
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• 1991

The lip seals widely used nowadays in stern tube sealing system of ships have radial sealing contact with shafts or liners, on the other hand the face seals of stern tube sealing system have axial sealing contact with seat. Because of axial sealing contact, the face seals have a large number of merits such as durability of life, simplicity of structure, easy fitting and replacement, etc. In this paper, for the purpose of development of face seals, the fundamental properties of axial sealing contact were analyzed and a trial face seal was designed and manufactured using N.B.R. rubber and Thordon which is widely used for bearing materials. The seal proper of trial face seal was made from N.B.R. rubber and the face insert was made from Thordon, thermosetting resins which are three dimensional, cross linked condensation polylmers. The performance test of trial face seal was carried out on the test bench which was specially designed and manufactured. The results were satisfactory enough to be used in practical stern tube sealing system.

• Journal of Chest Surgery
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• 제48권5호
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• pp.378-379
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• 2015

Mediastinitis is a life-threatening disease, and effective drainage is needed to treat mediastinitis with abscess formation. We recommend an alternative drainage method using chest tube binding with a Silastic Penrose drainage tube. The use of a Silastic Penrose drainage tube may help to manage mediastinitis with abscess formation. This method facilitates effective draining and prevents tissue adhesion.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.488-493
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• 2003

This paper presents new skill in tube-mill processing getting the increase in production efficiency and quality in response to the recent request of high grade pipe. In this study, researchers developed the method to improve the precision of pipe and tool life in tube-mill processing. Optimum tool shape is devised by analyzing various simulation and mechanism in cutting process. In order to verify the confidence of the proposed machining technology, it is applied to the real processing machinery in the field.

• 한국환경과학회지
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• 제17권10호
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• pp.1081-1092
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• 2008

This study was conducted to provide scientific information for establishing efficient and systematic measures for nature conservation and management in Manjang-gul lava tube. The number of vascular plants was 204 taxa (82 families, 176 genera, 144 species, 1 subspecies, 26 varieties and 1 forma). Of those, pteridophyte were 5 families, 12 genera, 14 species and 1 variety and gymnosperm were 4 families, 6 genera, 5 species and 1 variety. Seventy three families, 149 genera, 157 species, 1 subspecies, 24 varieties and 1 forma in angiosperm composed of 62 families, 123 genera, 137 species, 1 subspecies, 17 varieties and 1 forma in dicotyledon and 11 families, 26 genera, 20 species and 7 varieties in monocotyledon. The number of naturalized plants was 9 families, 17 genera, 18 species and 3 varieties, totaling 21 taxa.

• 한국가시화정보학회지
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• 제4권2호
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• pp.69-75
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• 2006

The microbubbles were used in various fields, such as turbulent control, drag reduction, material science and life science. The X-ray PTV using X-ray micro-imaging technique was employed to mea-sure the size and velocity of micro-bubbles moving in an opaque tube simultaneously. Micro-bubbles of $10{\sim}60{\mu}m$ diameter moving upward in an opaque tube (${\phi}$=2.7mm) were tested. Due to the different refractive indices of water and air, phase contrast X-ray images clearly show the exact size and shape of over-lapped microbubbles. In all of the working fluids tested (deionized water, tap water, 0.01 and 0.10M NaCl solutions), the measured terminal velocity of the microbubbles rising through the solution was proportional to the square of the bubble diameter. The rising velocity was increased with increasing mole concentration. The microbubble can be useful as contrast agent or tracer in life science and biology. The X-ray PTV technique should be able to extract useful information on the behavior of various bio/microscale fluid flows that are not amenable to analysis using conventional methods.

• 농업생명과학연구
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• 제43권6호
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• pp.105-109
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• 2009

경산 묘목단지는 대단위 과수종묘를 생산하고 있어 경쟁력 강화를 위하여 무독묘 보증 생산이 요구되고 있다. 특히 생산규모가 큰 사과종묘에 대한 빠르고 정확한 바이러스 진단이 시급하다. 본 연구에서는 사과바이러스 진단을 위하여 다량의 시료를 동시 분쇄할 수 있는 bead beater를 이용하였으며 분쇄 bead는 저가의 산업용 glass bead (0.4 mm 직경)를 일회용으로 채택하였다. RNA추출을 위하여서는 guanidine thiocyanate 용액이 Trizol 용액보다 효과적인 것으로 나타났으며 silica membrane tube의 이용으로 RNA추출 간편성을 높일 수 있었다. 사과바이러스는 RT-PCR에 의하여 검증하였다.

• 농업생명과학연구
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• 제44권4호
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• pp.29-43
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• 2010

The numerical analysis by using CFX 11.0 commercial code was done for proper design of the heat exchanger. The present experimental studies were also conducted to investigate the effects of circulating solid particles on the characteristics of fluid flow, heat transfer and cleaning effect in the fluidized bed vertical shell and tube type heat exchanger with counterflow, at which a variety of solid particles such as glass ($3mm{\Phi}$), aluminum ($2{\sim}3mm{\Phi}$), steel ($2{\sim}2.5mm{\Phi}$), copper ($2.5mm{\Phi}$) and sand ($2{\sim}4mm{\Phi}$) were used in the fluidized bed with a smooth tube. Seven different solid particles have the same volume, and the effects of various parameters such as water flow rates, particle diameter, materials and geometry were investigated. The present experimental and numerical results showed that the flow velocity range for collision of particles to the tube wall was higher with heavier density solid particles, and the increase in heat transfer was in the order of sand, copper, steel, aluminum, and glass. This behavior might be attributed to the parameters such as surface roughness or particle heat capacity.

• 설비공학논문집
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• 제25권8호
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• pp.438-442
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• 2013

The alternative refrigerant R436B is applied, to assess the application feasibility for a commercial cooling water system. The characteristic stability was verified by Sealed glass tube test and Autoclave test. R436B is chemically stable with the compressor material. The Oil miscibility test shows the usual compressor oil mixed well with R436B. Through the life acceleration test, the cooling performance is maintained. Though slight changes in oil and capillary tube diameter were found, they were within the permitted range. R436B should be applied to commercial cooling water systems as a simple replacement for the usual refrigerant.

• 한국응용곤충학회지
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• 제43권4호
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• pp.275-279
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• 2004

망사시험관 및 유리시험관에서 톱다리개미허리노린재의 약충발육, 성충수명 및 산란수를 비교하였다. 약충기간은 유리시험관(20일)보다 망사시험관(약 21일)에서 약 1일 길었는데, 이러한 차이는 주로 5령충의 발육기간에 기인되었다. 우화율은 유리시험관($56\%$)보다 망사시험관($64\%$)에서 $8\%$높았다. 성충수명은 유리시험관보다 망사시험관에서 암컷이 약 4.1배, 수컷이 약 6배 길었다. 산란전기간은 유리시험관보다 망사시험관에서 약 1일 길었으며, 산란수는 유리시험관보다 망사시험관에서 약 3.5배 많았다. 산란지속기간은 망사 시험관에서 약 30일, 유리시험관에서 약 8일 이었다. 따라서 톱다리개미허리 노린재의 발육특성을 정확하게 구명하기 위해선 공기유통이 원활한 망사시험관을 사용하는 것이 적합할 것으로 판단되었다.

• Nuclear Engineering and Technology
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• 제30권3호
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• pp.262-272
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• 1998

The experiences and causes of pressure tube cracking accidents in the CANDU reactors and the development of the fuel channel at AECL(Atomic Energy Canada Limited) have been described. Most of the accidents were caused by Delayed Hydride Cracking(DHC). In the cases of the Pickering units 3&4 and the Bruce unit 2, excessive residual stresses induced by an improper rolled joint process played a role in DHC. In the Pickering unit 2, cracks formed by contact between the pressure and calandria tubes due to the movement of the garter spring were the direct cause of the failure. To extend the life of a fuel channel, several R&D programs examining each component of the fuel channel have been carried out in Canada. For a pressure tube, the main concern is focused on changing the fabrication processes, e.g., increasing cold working rate, conducting intermediate annealing and adding a third element like Fe, V, and Cr to the tube material. In addition to them, chromium plating on the end fitting and increasing wall thickness at both ends of the calandria tube are considered. There has also been much interest in the improvement of fuel channel performance in our country and several development programs are currently under way.