• 자원리싸이클링
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• 제22권4호
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• pp.46-54
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• 2013

국내에서 발생하는 폐플라스틱의 양은 폐비닐류를 포함하여 연간 500만톤에 이르며 이 가운데 재활용 선별장을 통하여 배출되는 폐비닐류의 양은 연간 100만톤 정도에 이르는 것으로 추정되고 있다. 재활용 선별장의 폐비닐류는 RPF(Refuse Plastic Fuel) 또는 재생원료로 전환되어 재활용이 이루어지고 있다. 본 연구에서는 재활용 선별장에서 발생하는 폐비닐을 열매체 가열공정에 의하여 용융처리하여 재생 폐비닐 원료로서 이용가능성을 인장강도를 통하여 분석하고 기존의 재생품과 비교함으로서 용융재생원료의 이용 가능성을 판단하였다. 상업용으로 사용하기 위해서는 폐비닐류를 이용한 재생원료의 인장강도는 100 $kgf/cm^2$ 정도가 적합함을 알 수 있었다.

• 한국생산제조학회지
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• 제7권1호
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• pp.75-81
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• 1998

We have studied internal quality including chemical compositions, microscopic structure and nonmetallic inclusion of test materials. We have analyzed tensile strength value, hardness value, impact value etc. In analyzing internal quality, all of the test materials showed typical ferrite+pearlite structure. But nonmetallic inclusion showed oxide and sulfide inclusions in medium carbon steels, and sulfide inclusion is S-free cutting steels. In ca+ S-free cutting steels, the calcium aluminate and sulfide complex inclusion had low-melting points as deformation of sulfide and oxide inclusion is existed. It was found that tensile strength and hardness give maximum value in medium carbon steels, where as minimum in Ca + -free cutting steels. But values of elongation, reduction of area impact are reverse. Fracture surface of impact specimen is ductile in free cutting steels but brittle in medium cabon steels.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2018년도 공동국제학술발표회
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• pp.193-193
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• 2018

현재 우리나라는 레저선박 및 중소형 선박, 연안소형어선에 대부분 사용되는 재질은 강도가 높고 내양품성이 우수한 FRP를 사용하고 있다. 하지만 FRP선박의 폐선 시 환경문제와 자원재활용, 선체중량에 연비 및 대기오염등에 의해 소형선박 중심으로 알루미늄선 전환이 이루어지고 있다. 본 연구에서는 알루미늄 선체가 적용된 멀티하우스보트에 알루미늄선 구조기준에 따른 슬래밍하중을 적용하여 구조 강도평가를 실시하였으며, 그 결과를 통해 각 부재별 민감도 평가를 수행하여 알루미늄 구조강도기준을 만족함과 동시에 중량 저감을 하여 실제 선박설계에 적용시키고자 한다.

• 태양에너지
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• 제18권1호
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• pp.81-89
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• 1998

In this paper an experimental was done to design combustion chambers which is required radiation strength of high temperature generator of absorption rigerator. Partiqularly, in combustion chamber radiative mediums were set and basic experiments were done according to its size by radiation strength and effects of heat transfer promotion. The results are as follows : 1) When radiative mediums were set in small combustion furnace burning nonframely radiative heat transfer was effected. 2) In case that area ratio($A/A_o$) of radiative medium is 0.82 or over, temperature fluctuation effects of furnace inside were not nearly. 3) In experimental boundary heat transfer effects were 1.8 times by setting up radiative medium. Specially, $q/{\Delta}T$ values of furnace inside were uniformed nearly by setting up radiative mediums.

• 식물조직배양학회지
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• 제21권3호
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• pp.173-176
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• 1994

작약절편을 접종하면 배지와 절편이 흑갈색으로 변하고 수 이로부터 배양이 죽기 시작하는데 배지성분 중에 이를 조장하는 물질이 있음을 발견하였다. 즉 변색의 주원인은 철분과 염화칼슘(Cacl$_2$)이었고, 절편을 괴사시키는데 가장 큰 영양을 미친 것은 NO$_3$었다. 이 결과를 토대로 피해가 비교적 적은 1/4 MS를 번식용 배지로 이용하여 식물체의 모든 부분을 배양하였을 때 조직으로부터 재생은 전혀 일어나지 않았다. 다만 줄기절편에서 이미 형성된 액아가 유식물체로 성장하기도 하였으나 건전한 것으로 계속 성장하지 못하였으며 이것을 다시 번식체로 이용할 때는 초기 배양의 절편에서 나타나는 현상과 같은 원인으로 인하여 생존하지 못하였다.

• Journal of Plant Biotechnology
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• 제37권4호
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• pp.505-510
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• 2010

This study was conducted to refine a micropropagation method of water hyacinth (Eichhornia crassipes) in vitro. When young shoots were cultured on media with various concentrations of BA or TDZ alone, LS medium containing $5.0\;mgl^{-1}$ BA was found favorable for shoot proliferation from young shoots with a mean of 4.2 shoots. Using BA together with IAA, more shoots were obtained on LS medium containing $5.0\;mgl^{-1}$ BA and $1.0\;mgl^{-1}$ IAA with a mean of 5.7 shoots. In liquid medium, number of shoots and fresh weight per explant increased significantly. The best shoot proliferation and increasing of fresh weight were achieved on LS liquid medium containing $5.0\;mgl^{-1}$ BA and $1.0\;mgl^{-1}$ IAA with 6.9 shoots and more than 4,000 mg fresh weight. Of the different concentrations of LS salt, double strength of LS medium provided the highest shoot proliferation with 7.3 shoots, and fresh weight with 5,539 mg per explant. Shoot proliferation on LS medium containing $50\;gl^{-1}$ sucrose had better results with 8.7 shoots and 5,979 mg per explant in fresh weight than other conditions. In conclusion, the optimal level for shoot proliferation and biomass increase of water hyacinth was attained with the application of the double strength of LS medium containing $5.0\;mgl^{-1}$ BA, $1.0\;mgl^{-1}$ IAA and $50\;gl^{-1}$ sucrose.

• Journal of Electrical Engineering and Technology
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• 제11권6호
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• pp.1783-1786
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• 2016

The paper investigates the insulation properties of the supercritical $CO_2$ ($SCCO_2$) fluid as an insulating medium for electrical apparatuses. The insulating material is crucial for electrical apparatuses and $SF_6$ gas has been widely used for high power electrical apparatuses. There have been many research efforts to develop substituents for $SF_6$ gas because of high global warming potential. We obtained above 350 kV/mm insulation strength with 12.0 MPa $SCCO_2$. The positive and negative IEC standard pulses are applied between two 10 mm diameter spherical electrodes. The insulation strength of $SCCO_2$ is at least 2.5 times higher than that of $CO_2$ gas at 6.0MPa. The insulation strength of $SCCO_2$ fluid is about 10 times higher than that of $SF_6$ at 0.5MPa which is the ordinary operating pressure of electrical switchgears. Using the result, we expect that the time for switching and dielectric recovery could be reduced using $SCCO_2$ fluid as an insulating medium.

• 한국생산제조학회지
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• 제6권1호
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• pp.45-50
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• 1997

It is not clearly known how surface defects or inclusions of a medium carbon steel affect a fatigue strength. In this study, we used SM35C specimens with spheroidized cementite structure to eliminate dependence of micro structure of fatigue crack. The investigation was carried out by behavior of crack closure at non-propagation crack and effect of the fatigue limit according to the artificial defects size. Experimental findings are obtained as follows : (1) Fatigue crack initiation point of medium carbon steel with spheroidized cementite structure is at the surface defects. (2) Non-propagating crack length of smooth specimen is equal to the critical size of defect. (3) Considering the opening and closure behavior of fatigue crack, the defect shape results in various crack opening displacement, while it does not affects the fatigue limit level of medium carbon steel with spheroidized cementite structure. (4) The critical length of the non-propagation crack of smooth specimen is the same as critical size of defect in transient area which determines threshold condition in steel with spheroidized cementite structure.

• 식물조직배양학회지
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• 제21권4호
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• pp.221-225
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• 1994

주요 약용작물로 사용하고 있는 천궁의 경정을 기내배양 하여 건전한 종경을 대량으로 증식하는데 적함한 배양조건을 구명하기 위하여 실험한 결과를 요약하면 7월에 채취한 재료를 1%의 NaOCI에 20분간 표면살균한 후, carbenicillin 500 mg/L, BA 1.0 mg/L 와 $GA_3$ 1.0 mg/L가 첨 가된 1/2 MS배지가 오염율 감소와 신초 재분화율을 높이는데 효과적이었고, 재분화한 신초의 기내증식은 BA 0.5 mg/L와 당 60 g/L가 함유된 1/2 MS가 양호하였으며 이들 유묘는 1/2 MS에 NAA 3.0 mg/L 단용배지에서 배양하였을때 발근하였다.

• 펄프종이기술
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• 제47권1호
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• pp.1-9
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• 2015

Wood fibers for medium density fiberboard (MDF) was used in the filler layer of the white duplex board for increasing thickness and bulk of the board. The MDF fibers were treated with ozone (3% based on dry weight of the fibers), and mixed together with OCC (old corrugated container) to form paper. Ozone-treated MDF fibers gave high bulk, high tensile strength, high internal bond and fast drainage to the furnish mixed with OCC. It was shown that there were possibilities to reduced basis weight of the filler layer without loss of thickness, stiffness, and tensile strength. Furthermore, it showed the possibility to develop a new kind of board product that has high stiffness as well as high strength properties with light basis weight by application of the ozone-treated MDF fibers.