• 폴리머
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• 제35권6호
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• pp.513-519
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• 2011

침투 가능한 구형 모델 유체의 충돌 특성을 고찰하고자 분자 동력학 방법을 이용한 전산 모사를 수행하였다. 이로부터 다양한 범위의 입자 충전 분율 ${\phi}$ 및 척력적 에너지 ${\varepsilon}^*$ 조건에 대한 충돌 빈도수, 평균 자유 행로, 강체형 반사 충돌각 및 연체형 침투 충돌각의 분포도, 유효 충전 분율 등을 계산하였다. 낮은 척력적 에너지 조건에서는 연체형 충돌이 주된 특성이나, 반면 높은 척력적 에너지 조건에서는 강체형 충돌이 주된 요인이었다. 매우 흥미롭게도, 전체 충돌 빈도수에 대한 연체형 충돌비(또는, 강체형 충돌비)는 정준 앙상블의 몬테카를로 전산 모사에서 받아들임 확률(또는, 되돌림 확률)로 표시되는 볼쯔만 인자와 직접적으로 관계되었다. 이와 같은 거동 입자들의 동적 충돌 특성들은 ${\varepsilon}^*{\geqq}3.0$ 및 ${\phi}{\geqq}0.7$ 범위의 높은 척력적 에너지 및 높은 충전 분율 조건에서 제한적이었으며, 이는 침투성 구형 모델에서 나타나는 클러스터 형성 구조를 함축하고 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.613-618
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• 2001

For the evaluation of operability of MOV(Motor Operated Valve), the precision prediction of thrust/torque acting on the valve is important. In this paper, the analytical prediction method of thrust/torque was proposed. The design basis stem thrust calculation typically considers the followings: Packing thrust, Stem rejection load, design basis differential pressure load. In general, test results show that temperature, pressure, fluid type, and differential pressure, independently and combination, all have an effect on the friction factor. The prediction results of thrust/torque are well agrement with dynamic test results.

• Journal of Korean Vacuum Science & Technology
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• 제6권1호
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• pp.51-54
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• 2002

Polymer EL devices of glass/ITO/PI/MEH-PPV/Al structure were fabricated using spin coating and the Ionized Cluster Beam deposition technique. PMDA-ODA type thin polyimide films which can be used as a impurity blocking layer of EL device were deposited by ICB. According to our previous results, the packing densities of polyimide films were subject to change and depend on their deposition condition. By inserting a Pl layer with various thickness and packing density, I-V characteristics and life time of the devices were investigated to determine the role of a interlayer. The blocking of impurity diffusion from ITO to luminescent layer were confirmed by XPS.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.90-93
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• 2006

Buried pipeline is a indispensable factor of leading smoothly a society as a primary role. Recently, as a matter of convenience of construction and the economical purpose, the use of Precast Concrete products quickly increased. But there was various damage forms in a part of joint of Precast Concrete buried pipeline. The purpose of this study is to propose the new type of the flexible rubber packing material (EF) which could resist a permanent deformation of the ground or an earthquake and to investigate its safety together with effectiveness as conducting experiment and analysis.

• Journal of Advanced Marine Engineering and Technology
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• 제28권3호
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• pp.451-456
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• 2004

This present experimental study has dealt with the heat transfer characteristics of plastic particle slurry which flows in a circular tube. This type of slurry is suggested for heat transfer enhancement effect cause by random and vortex effect of plastic particle dispersed in water. As a result, the thermal boundary layer becomes thin so the heat transfer coefficient on the tube wall more increase compare to pure water flow. This experimental test section was composed with stainless pipe which has the length of 2000mm, inner pipe diameter of 14mm and outer pipe diameter of 60mm. The most effective and important parameter of this experiment is plastic packing factor(PPF). The focuses of these results are pressure drop and heat transfer coefficient. As results, the friction factor of plastic particle slurry becomes higher at laminar flow region than pure water because of buoyancy effect of plastic particle but the local heat transfer coefficient becomes higher.

• 한국가스학회지
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• 제12권3호
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• pp.64-67
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• 2008

초고압 공압용 패킹을 적용한 밸브를 개발하여 밸브의 수명 및 기밀도를 높이고자 하였다. 밸브핸들 부위를 통하여 잔압을 제거할 수 있는 구조를 구현하여, 별도의 드레인밸브가 필요 없는 효과적인 밸브를 개발하였으며 특성은 밸브 팩킹을 특수한 형태로 가공하고, 기둥에 드레인 홀을 구성하여, 밸브가 열리거나, 닫힌 상태에 관계없이 드레인이 가능하도록 하였다.

• 펄프종이기술
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• 제32권3호
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• pp.32-38
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• 2000

This study was carried out to determine the effect of the type of plastic pigment on the coat-ing structure and printability of coated paper. Three kinds of plastic pigments(solid-bead type binder type and hollow type) were used for hti purpose. IN this research it was observed that particle shape and structure of plastic pigment had influenced the rheology of coating color the state of packing and the properties of coated paper. Inorganic pigments used in this research were platelike kaolin clay and rhombic calcium carbonate. Three kinds of plastic pigments were blended with two inorganic pigments respec-tively. The combination of pigments were carried out(1) to determined the effect of particle structure of plastic pigment on the state of dispersion of coating color(2) to observe the effect of calendering temperature on the property of coated paper prepared with different plastic pigments. The data indicated that binder and hollow type plastic pigment gave the best results in improving the properties of coated paper such as paper gloss opacity and air pet-meability.

• 한국식품영양과학회지
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• 제37권2호
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• pp.231-238
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• 2008

본 연구에서는 1 및 $5^{\circ}C$의 냉수와 $13^{\circ}C$의 지하수를 이용하여 세척한 후 PP film bag과 PETE tray로 포장하여 4 및 $10^{\circ}C$에서 9일간 저장하며 품질을 비교하였다. $1^{\circ}C$ 냉각수로 세척하고 PETE tray로 포장한 경우 0.25%로 감모율이 가장 낮았고 이는 같은 냉수로 세척한 후 PP film bag로 포장한 0.39%보다 더 낮게 나타났다. 호흡속도는 $1^{\circ}C$ 냉수세척 처리하여 PETE tray로 포장하고 4 및 $10^{\circ}C$에서 저장한 9일 후 각각 45.71 및 53.15 mg $CO_2/kg/hr$로 PP film bag으로 포장한 경우보다 낮은 호흡률을 나타내었다. 표면색 변화에 있어서는 L 및 b값이 크게 변하지 않았고 비타민 C의 경우 초기 35 mg% 내외에서 저장 9일째에 $12{\sim}20\;mg%$로 감소하였으며, 1 및 $5^{\circ}C$의 세척수 온도별 유의적인 차이는 5 mg% 정도로 크지 않았다. 저장 9일째 $4^{\circ}C$에서 $1^{\circ}C$ 세척 처리하고 PETE tray로 포장하여 저장한 깻잎의 총균수는 $6.25{\times}10^4\;CFU/g$, 대장균군수는 $5.95{\times}10^2\;CFU/g$로 미생물수의 증식속도가 가장 느렸다. $1^{\circ}C$ 냉수로 세척하고 PETE tray로 포장하여 $4^{\circ}C$로 저장한 경우 깻잎 고유의 초록색과 향을 유지하고 있어 저온냉수 세척과 tray 포장이 세척 청경채의 선도 유지에 효과가 있는 것으로 나타났다.

• 한국식품저장유통학회지
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• 제15권1호
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• pp.1-8
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• 2008

본 연구예서는 1 및 $6^{\circ}C$의 냉수를 이용하여 세척한 후 PP film bag과 PETE tray로 포장하여 4및 $10^{\circ}C$에서 9일간 저장하며 품질을 비교하였다. $4^{\circ}C$에서 9일간 저장한 경우 1 및 $6^{\circ}C$에서 세척하고 PEIE tray로 포장한 청경채에서 감모가 거의 일어나지 않았다. $10^{\circ}C$ 저장고에서 9일째 저장한 경우 무처리하고 PP film bag으로 포장한 청경채의 감모율 0.37 %에 비하여 $1^{\circ}C$로 세척하고 PETE tray로 포장한 경우 감모율은 0.19 %로 낮게 나타났다. 호흡속도는 $1^{\circ}C$ 냉수 세척 처리하여 PETE tray로 포장하고 4및 $10^{\circ}C$에서 저장한 9일 후 각각 38.41 및 43.11mg $CO_2$/kg/hr로 PP film bag으로 포장한 청경채의 9일째 호흡속도 48.16및 59.47mg $CO_2$/kg/hr보다 낮게 나타났다. 저장 9일째 $1^{\circ}C$ 냉각수로 세척 처리하고 PETE tray로 포장하여 $4^{\circ}C$에 저장한 경우 무처리한 청경채의 총균수는 $1.0{\times}10^5$ CFU/g, 대장균군수는 $1.3{\times}10^1$ CFU/g였으며 6일째까지 대장균군수는 검출되지 않았다. PETE tray으로 포장된 경우보다 PP film bag로 포장된 경우 잎의 변색과 조직의 변화가 더욱 심하였으며 $1^{\circ}C$ 냉수로 세척하고 PETE tray로 포장하여 $4^{\circ}C$로 저장한 경우 청경채 고유의 초록색과 아삭한 조직감을 유지하고 있어 저온냉수 세척과 tray포장이 세척 청경채의 선도 유지에 효과가 있는 것으로 나타났다.

• 대한두개안면성형외과학회지
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• 제22권6호
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• pp.319-323
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• 2021

Background: Prophylactic antibiotics are used to prevent surgical wound infection; however, proper indications must be followed with careful consideration of the risks and benefits, especially in clean or clean-contaminated wounds. Nasal bone fractures are the most common type of facial bone fracture. The most common method for treating nasal bone fracture is closed reduction, which is performed inside the nasal cavity without an incision. The purpose of this study was to determine the need for antibiotic use in the closed reduction of nasal bone fractures. Methods: A retrospective study was conducted using data from the National Insurance Service Ilsan Hospital of the Republic of Korea between 2016 and 2018. The records of patients who underwent closed reduction of nasal bone fracture were reviewed and classified according to sex, age, comorbidities, perioperative antibiotic usage, postoperative complications, nasal packing, anesthesia type, surgeon's specialty, and operation time. Results: Among the 373 patients studied, the antibiotic prescription rate was 67.3%. Just 0.8% of patients were prescribed preoperative antibiotics only, 44.0% were prescribed postoperative antibiotics only, and 22.5% were prescribed both preoperative and postoperative antibiotics. There were no cases that satisfied the definition of "surgical site infection." Furthermore, 2.1% of infection-related complications (e.g., mucosal swelling, synechia, and anosmia) occurred only in the antibiotic usage group. The use of nasal packing, anesthesia type, and surgeon's specialty did not show any difference in infection-related complication rates. Conclusion: According to the study findings, the routine use of perioperative antibiotics is not recommended in uncomplicated nasal bone fracture surgery.