• 한국식품과학회지
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• 제23권4호
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• pp.420-427
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• 1991

배추의 염절임 및 가열처리 중의 조직구조 변화를 현미경적으로 관찰하고 펙틴질을 분별 정량하였으며 조직의 내부구조를 cytorrhysis로 측정하였다. 배추줄기 조직의 유세포의 세포막은 염절임시 수축 파괴되며 세포간 공간의 포집공기와 세포액은 세포수축과 함께 중엽을 파괴하면서 유출되었다. 배추조직의 펙틴은 주로고 메톡실 펙틴인 pA와 저 메톡실 펙틴인 pB로 구성 되었고 염절임 및 $60{\sim}70^{\circ}C$의 저온 가열시 상당량의 pA는 작용으로 pB로 전환되었고 $80^{\circ}C$ 이상으로 가열처리하면 열분해로 pB가 감소되었으며 열처리 중 조직의 firmness는 pB의 함량과 상관관계가 높았다(r=0.996). Cytorrhysis 실험결과 염절임 및 $60^{\circ}C$의 저온처리에서는 조직의 pore size가 더 작아졌고 $80^{\circ}C$ 이상의 고온 열처리에 의하여 조직의 pore size가 커졌는데 이는 저온에서 pB의 증가에 의해 조직이 더 치밀해지고 고온 열처리에서는 가열분해된 pB가 용출되면서 조직이 더 엉성해졌기 때문인 것으로 판단되었다.

• Journal of Welding and Joining
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• 제34권1호
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• pp.41-46
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• 2016

With the recent increase in size of ships and offshore structures, there are more demand for thicker plates. As the thickness increases, it is known that fatigue life of the structures decrease. To improve the fatigue life, post weld treatments techniques, such as toe grinding, TIG dressing and hammer peening, are typically employed. However, these techniques require additional construction time and production cost. Therefore, it is of crucial interest steels with longer fatigue crack growth life compared to conventional steels. This study investigates fatigue crack growth rate (FCGR) behaviours of conventional EH36 steel and Ferrite-Bainite dual phase EH36 steel (F-B steel). F-B steel is known to have improved fatigue performance associated with the existence of two different phases. Ferrite-Bainite dual phase microstructures are obtained by special thermo mechanical control process (TMCP). FCGR behaviours are investigated by a series of constant stress-controlled FCGR tests. Considering all test conditions (ambient, low temperature, high stress ratio), it is shown that FCGR of F-B steel is slower than that of conventional EH36 steel. From the tensile tests and impact tests, F-B steel exhibits higher values of strength and impact energy leading to slower FCGR.

• 생명과학회지
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• 제20권2호
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• pp.208-212
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• 2010

작물의 수량과 품질은 저온 및 고온 스트레스에 영향을 받는 것으로 알려져 있다. 본 연구에서는 배추에서의 스트레스 저항성과 연관된 분자마커를 개발하기 위하여 저온에서의 스트레스 저항성에 영향을 미치는 것으로 알려져 있는 alternative oxidase (AOX) 합성 유전자 관련 분자 마커를 개발하였다. 총 15개의 AOX 합성 유전자와 관련된 Brassica rapa ESTs를 arabidopsis AOX 합성 유전자 염기서열을 이용하여 찾을 수 있었다. 이를 이용하여 고온에서 상대적으로 약한 '지부'품종과 상대적으로 강한 '권심' 사이에서 DNA 염기서열을 조사하여 4개의 ESTs에서 insertion 또는 deletion을 찾았고 PCR로 확인 가능한 4개의 공동우성 마커를 개발하였다. 본 연구에서 개발된 분자마커는 배추 작물에서 환경스트레스 저항성과 유전적 연관성을 확인하는데 유용하게 사용될 수 있다고 기대된다.

• 한방안이비인후피부과학회지
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• 제23권3호
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• pp.1-10
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• 2010

Objective : Erysipelas is an acute inflammation caused by pyogenic bacteria. This mainly involves the upper part of dermis. It begins as erythematous patches with tenderness, followed by fever, headache, chills and fatigue etc. It may results in edema, obstruction of lymphatics and sepsis. So this experiment is carried out for test whether the Bojeasodok-um subtracted Scrophulariae Radix, Lasiosphaera seu Calvatia, Isatidis Radix added indigo Naturalis, Lithospermi Radix have an anti-inflammatory effect and have suppression effect on immunocyte in the state of inflammation which induced by Erysipelas. Method : Experimental animals made use of 4-5 week-age(weight 20-25g) ICR(male) mouse. In the breeding farm, the lighting time was controlled from 7:00 am till 7:00 pm, the temperature was controlled So we concluded that BS is prospected as an anti-inflammatory agent to cure inflammation induced bywithin 18-23$23^{\circ}C$ and water and food were not limited.The freezing lyophilization powder which were extracted from Bojesodok-Um divided low dose group(200mg/kg-BSL) and high dose group(500mg/kg-BSH) and after melting in water, it was orally administered to the mouse. Compared with inflammation induced group which were induced by triggering-inflammation reagent Carageenan and Zymosan and normal contrast group, we measured the edema decrement effect,macrophage and spleen cell activation. Result : 1. BS has suppress inflammatory reaction induced by Carageenan. 2. BS has suppress increasing activation of abdominal cavity macrophage in the Carageenan and Zymosan induced inflammation. 3. BS has suppress increasing activation of spleen cell in the Carageenan and Zymosan induced inflammation. Based on the above result, BS was improved its suppression effect to the inflammatory reaction through the suppression of spleen cell and macrophage activation. So we concluded that BS is prospected as an anti-inflammatory agent to cure inflammation induced by Erysipelas.

• 센서학회지
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• 제29권1호
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• pp.27-32
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• 2020

This study proposes a pixel-patterning method for organic light-emitting diodes (OLEDs) based on thermal transfer. An infrared lamp was introduced as a heat source, and glass type donor element, which absorbs infrared and generates heat and then transfers the organic layer to the substrate, was designed to selectively sublimate the organic material. A 200 nm-thick layer of molybdenum (Mo) was used as the lightto-heat conversion (LTHC) layer, and a 300 nm-thick layer of patterned silicon dioxide (SiO₂), featuring a low heat-transfer coefficient, was formed on top of the LTHC layer to selectively block heat transfer. To prevent the thermal oxidation and diffusion of the LTHC material, a 100 nm-thick layer of silicon nitride (SiN_x) was coated on the material. The fabricated donor glass exhibited appropriate temperature-increment property until 249 ℃, which is enough to evaporate the organic materials. The alpha-step thickness profiler and X-ray reflection (XRR) analysis revealed that the thickness of the transferred film decreased with increase in film density. In the patterning test, we achieved a 100 ㎛-long line and dot pattern with a high transfer accuracy and a mean deviation of ± 4.49 ㎛. By using the thermal-transfer process, we also fabricated a red phosphorescent device to confirm that the emissive layer was transferred well without the separation of the host and the dopant owing to a difference in their evaporation temperatures. Consequently, its efficiency suffered a minor decline owing to the oxidation of the material caused by the poor vacuum pressure of the process chamber; however, it exhibited an identical color property.

• 한국정밀공학회지
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• 제29권3호
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• pp.324-333
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• 2012

The conventional medium and large caliber gun, in general, utilize the hydro-pneumatic recoil mechanism to control the firing impulse and to return to the battery position. However, this kind of mechanism may cause the problems like the leakages and the property changes in oil and gas due to the temperature variations between low and high temperatures. Accordingly, the friction spring mechanism has recently been researched as an alternative system. The friction spring mechanism consists of a set of closed inner and outer rings with the concentric tapered contact surfaces assembled in the columnar form, and can only be used under the compression load. When the spring column is axially loaded, the tapered surfaces become overlapped, causing the outer rings to expand while the inner rings are being contracted in diameter allowing an axial displacement. Because of friction between tapered contact surfaces, much higher spring stiffness is obtained on the stroke at the increase in load than the stroke at the decrease. In this paper, the dynamic equations regarding the friction spring system and the design approach have been investigated. It is also tried for a dynamic model representing the recoil motion and the friction spring forces. And the model has been proved from firing test using a gun system with friction springs. All the results show that the recoil mechanism using friction springs can substitute for the classic hydro-pneumatic recoil system.

• 대한기계학회논문집
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• 제16권8호
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• pp.1575-1582
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• 1992

본 연구에서는 정상운전 중인 4사이클 6실린더 터보과급 디젤기관에 갑자기 큰 부하가 작용하였을 경우, 기관 및 과급기 관성 모멘트의 변화가 기관과 과급기의 실제 회전속도, 압축기 압력비, 실린더내 공기유량, 연소효율, 배기온도 등의 과도 응 답성능에 미치는 영향을 시뮬레이션해석과 실험을 통하여 규명하였다.

• 한국항행학회논문지
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• 제24권1호
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• pp.1-8
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• 2020

본 연구에서는 항공기에 장착하여 S/C대역의 신호를 장거리 표적으로 방사하기 위한 장치를 개발하였다. 장치는 요구된 실효 등방성 복사전력을 충족시키기 위해 대역별 송신기와 광대역 안테나로 RF 인터페이스를 구성하였다. 장치의 외형은 항공기 연료탱크와 동일한 포드(pod) 형상으로 설계했고, 측정된 장치의 중량은 119.8 kg, 무게중심은 1391.35 mm 그리고 관성 모멘트는 46.07 ± 0.05(I_yy) kg·㎡과 45.36 ± 0.09(I_zz) kg·㎡로 모두 항공기 장착을 위한 요구도를 충족함을 확인하였다. 비행 안전을 확인하기 위해 전자기 간섭 시험(RE102, CE102), 환경시험(고온/저온 운용, 고도), 체계 내 전자기 적합성 시험 그리고 인체 전자기 복사 위해도 시험을 수행하였으며, 모든 항목의 시험 결과가 요구사항을 충족함을 확인하였다. 장치는 요구되는 전기적/기계적으로 요구되는 사항을 모두 충족함으로써 항공기 장착이 가능함을 확인하였다.

• 한국분말재료학회지
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• 제24권6호
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• pp.450-456
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• 2017

Reaction-bonded silicon carbide (RBSC) is a SiC-based composite ceramic fabricated by the infiltration of molten silicon into a skeleton of SiC particles and carbon, in order to manufacture a ceramic body with full density. RBSC has been widely used and studied for many years in the SiC field, because of its relatively low processing temperature for fabrication, easy use in forming components with a near-net shape, and high density, compared with other sintering methods for SiC. A radiant tube is one of the most commonly employed ceramics components when using RBSC materials in industrial fields. In this study, the mechanical strengths of commercial RBSC tubes with different sizes are evaluated using 3-point flexural and C-ring tests. The size scaling law is applied to the obtained mechanical strength values for specimens with different sizes. The discrepancy between the flexural and C-ring strengths is also discussed.

• Journal of Welding and Joining
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• 제14권3호
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• pp.48-57
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• 1996

A study was made to examine the characteristics of base metal and stress relief cracking(SRC) of heat affected zone(HAZ) for HY-100 and Cu-bearing HSLA-100 steels. The Gleeble thermal/mechanical simulator was used to simulate the SRC/HAZ. The details of mechanical properties of base plate and SRC tested specimens were studied by impact test, optical microscopy and scanning electron microscopy. The specimens were aged at $650^{\circ}C$ for HSLA-100 steel and at $660^{\circ}C$ for HY-100 steel and thermal cycled from $1350^{\circ}C$ to $25^{\circ}C$ with a cooling time of $\Delta$t_${800^{circ}C/500^{circ}C}$=21sec. corresponds to the heat input of 30kJ/cm. The thermal cycled specimens were stressed to a predetermined level of 248~600MPa and then reheated to the stress relief temperatures of $570~620^{\circ}C$. The time to failure$(t_f)$ at a given stress level was used as a measure of SRC susceptibility. The strength, elongation and impact toughness of base plate were greater in HSLA-100 steel than in HY-100 steel. The time to failure was decreased with increasing temperature and/or stress. HSLA-100 steel was more susceptible to stress relief cracking than HY-100 steel under same conditions. It is thought to be resulted from the precipitation of $\varepsilon$-Cu phase by dynamic self diffusion of solute atoms. By the precipitation of $\varepsilon$-Cu phase, the differential strengthening of grain interior relative to grain boundary may be greater in the Cu-bearing HSLA-100 steel than in HY-100 steel. Therefore, greater strain concentration at grain boundary of HSLA-100 steel results in the increased SRC susceptibility. The activation energies for SRC of HSLA-100 steel are 103.9kcal/mal for 387MPa and 87.6kcal/mol for 437MPa and that of HY-100 steel is 129.2kcal/mol for 437MPa.