• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.100-100
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• 2004

미국에서 발명된 초미세 발포기술은 기존의 발포공법과는 달리, 가스(CO2, N2)에 의해 재료에 생성된 기포(셀)의 크기가 loom이하인 작은 셀이 재료 내에 고르게 분포되도록 하여, 기존의 발포재료보다 나은 기계적 특성을 유지하도록 하였다. 그 결과, 제품의 재료비를 절감하기 위해 연구된 MCPs는 기존의 발포기술과는 달리 재료의 기계적 강도 저하를 극복하고 충격 강도와 인성의 향상을 가져왔다. 그리하여, 현재 국내의 자동차업체의 범 퍼 및 내장재로의 사용을_시작으로 산업의 다각적인 분야에 이용되고 있다.(중략)

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.75-76
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• 2014

Copper는 2차 전지 및 PCB 등 Electrical Device에 빠짐없이 들어가는 핵심 부품이다. 반도체 배선재료 또한 Aluminum에서 Copper로 대체되어 Electrical Conductivity 및 Electro-migration 문제를 해결할 수 있었다. 최근 배선의 미세화 및 전지용량 증가로 인해 보다 얇으면서, 동시에 높은 기계적 강도를 가지는 Copper Film의 필요성이 요구되고 있다.

• 기계와재료
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• v.22 no.2
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• pp.32-47
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• 2010

온실가스 배출 규제로 대표되는 환경문제가 시급한 경제 사회적 현안이 됨에 따라 자동차 차체경량화에 인한 연료소모 및 배기가스 감소를 통하여 각종 환경규제에 대응하고 환경친화형 산업으로 형성되는 새로운 시장을 선점하려는 노력이 전세계적으로 치열하게 경주되고 있다. 자동차 중량의 대부분을 점유하고 있는 철강소재의 경량화는 차체 경량화의 척도로 평가되어 왔으며, 미래형 자동차의 출현에 대응하기 위한 철강산업계의 노력도 치열하게 경주되고 있다. 고부가가치 강판의 최대 수요처인 자동차 산업의 동향과 이에 관련한 최근의 자동차용 강판의 연구개발 현황 및 차세대 고강도 강판의 연구개발 동향에 대해 소개한다.

• Korean Journal of Materials Research
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• v.4 no.1
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• pp.24-30
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• 1994

Effect of low temperature retrogression on RRA treatment were investigated in the thermomechanically treated 7075 Al alloy. The complete dissolution of GP zones did not occur during retrogression at $170^{\circ}C$ in T6 material. llrop in strength during initial stage of retrogression was due to the partial dissolution of GP zones. And the strength increased with the formation of $\mu '$ and decreased again with the growth of $\mu '$ and/or formation of $\mu '$ When RRA treatment was applied at the minimum or the secondary peak (maximum) in the hardness curve of retrogression treatment, SCC property was improved markedly without reduction of the strength in comparision with that of T6 materials. And the rhanges in the matrix were not sensitive with time during retrogression at low temperature of $170^{\circ}C$ that the strength and SCC properties were similar at both points in the hardness curve of retrogression treatment.

• Korean Journal of Medicinal Crop Science
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• v.10 no.2
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• pp.82-87
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• 2002

This study was conducted to investigate the influence of shading treatment on the photosynthetic rate, transpiration rate, stomatal conductance and its any correlations in Liriope platyphylla $W_{ANG}\;et\;T_{ANG}$. Followings were achieved as a conclusion. The net photosynthetic rate was increased as the PAR was increased and reached maximum at the $700-1000{\mu}mol/m^2/s$ of PAR in all of leaves, also this treatment caused a higher net photosynthetic rate in comparison with control. It shows the tendency of increasing stomatal conductance caused by the increment of PAR. The diurnal changes of photosynthesis, transpiration rate and stomatal conductance were increased as the PAR was increased in the morning, but they indicated a decreased tendency in broad day. The relationship between net photosynthetic rate and stomatal conductance is well fit by the first regression linear equation. However, the values obtained from the linear equation have the different, respectively, and have highly significance. From the above results, net photosynthetic rate of shading treatment is higher than control in the same stomatal conductance. Different first regression linear equation were obtained between the transpiration rate and stomatal conductance, photosynthesis and stomatal conductance in during the control and shading treatment, too.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.265-265
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• 2019

기후변화로 의한 기온의 상승은 가뭄, 홍수와 같은 재해를 일으킬 뿐만 아니라 깊은 호수나 저수지와 같은 수자원에도 용존 산소, 물질, 영양소 및 식물플랑크톤의 수직적 분포 등과 같은 다양한 부분에 영향을 미친다. 본 연구의 목적은 SWAT, HEC-ResSim 및 CE-QUAL-W2(이하 W2)모델을 사용하여 미래의 기후 변화에 따른 소양호의 수온, 성층강도 및 열적 안정성의 변화를 장기 예측하고 그 영향을 평가하는데 있다. W2 모델의 보정은 2005 년부터 2015 년까지의 실측 과거 데이터를 이용하여 보정하였고 기후변화 시나리오는 IPCC의 AR5 RCP 4.5 시나리오를 사용하였다. 기후자료는 GCM 모델인 HadGEM2-AO 결과를 상세화하여 모의기간의 자료를 생성하였다. SWAT모델을 이용하여 모의기간인 2016 년부터 2070 년까지 일단위로 저수지 유입을 예측했으며 HEC-ResSim모델을 이용하여 소양강댐 저수지 운영 조건에 따라 저수지 방류량 및 수위 변화를 모의하였다. 수온 해석을 위해 W2를 적용하여 저수지의 장기간의 수온 변화를 예측하였다. 결과적으로 대기 온도는 $0.0279^{\circ}C/year$(p < 0.05) 상승할 것으로 예측되었으며, 동일기간 상층(수면으로부터 5m 깊이)과 하층 (바닥으로부터 5m 높이) 수온은 각각 $0.0191^{\circ}C$/년(p < 0.05) 및 $0.008^{\circ}C$/년(p < 0.05) 상승할 것으로 예측되었다. 모의된 수온을 계절별로 분석했을 때 상층수온은 여름철 가장 큰 폭으로 상승하였으며 하층의 경우 겨울철에 가장 큰 폭으로 상승하였다. 계절별 상-하층 수온의 차는 여름이 가장 컸으며, 겨울에 온도차가 가장 작았다. 또한 미래 온도의 상승에 따라, 소양호의 성층 강도가 강해지는 경향을 보였으며 상층 및 하층의 온도차 $5^{\circ}C$를 기준으로 성층이 형성되는 기간은 큰 변동이 없었으나 소멸되는 시점이 점점 늦어지는 추세를 보여 성층 형성 기간이 길어지는 것으로 나타났다. 저수지 표면의 수온 상승은 식물플랑크톤의 계절 성장률에 영향을 미쳤는데, 특정 조건에서 규조류는 최적 성장 범위를 벗어나는 고온 조건에서 성장속도가 감소하였으나 녹조류와 남조류의 출현 시기가 빨라지며 장기화될 것으로 예측되었다.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.7
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• pp.511-523
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• 1989

This paper investigates physical properties, the electrical and mechanical characteristics of the epoxy resin with different curing methods and postcuring conditions at room temperature or cryogenic temperature (LN2). According to the results in this paper, first, it is found that the physical properties, electrical and mechanical characteristics of the epoxy resin are largely affected by the interior reaction temperature on the curing. Thus, in the fabrication of the sample, several excellent characteristics of the sample are obtained by controlling the interior reaction temperature of the epoxy resin. Second, the sample having optimal electrical and mechanical characteristics is obtained for the repetitive post-curing method at 100c in view point of the post-curing conditions of the epoxy resin. Third, it appears that tan and characteristics at LN2 temperature are about half of those at room temperature. Fourth, it appears that the dielectric strength of the epoxy resin at LN2 temperature is higher by about 0.6-1.0 MV/cm than that at room temperature. The heat-aging of the epoxy resin due to the micro-defect and excess fever-movement have been noticed to affect dielectric strength at LN2 temperature more significantly than at room temperature.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.2
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• pp.345-349
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• 2019

The National Aeronautics and Space Administration (NASA) has long been studying the essential elements of manned planetary exploration and has held several international challenges to encourage the research works related to it. One of them was the NASA Centennial Challenge Programs which started in 2015. Following the second in 2017, the third is currently going on in 2019. Participating "3D-Printed Habitat Challenge", one of the challenges in the second program, this research team designed and developed the 3D printer extruding module for the Lunar Simulant (Korea Hanyang Lunar Simulant-1; KOHLS-1) and the polymer. For optimizing the modul, a cylindrical specimen of ${\varnothing}150{\times}300mm^3$ volume and a specimen of $200{\times}100{\times}650mm^3$ volume were manufactured and their compressive and flexural strengths were tested. The findings can help automatize the space construction in the future.

• Journal of the Korea Concrete Institute
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• v.28 no.1
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• pp.95-104
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• 2016

Flexural strength of concrete ground slab reinforced with steel fiber is evaluated using the equivalent flexural strength ratio of steel fiber reinforced concrete based on the yield line theory. Recently, the European standard specifies that the tensile performance of the steel fiber reinforced concrete be evaluated directly from the residual flexural strength after the cracking of concrete. Thus, in the study, an experiment was carried out to evaluate the conventional equivalent flexural strength ratio and the residual flexural strength of the steel fiber reinforced concrete. Then the design flexural strength was investigated according to the location of a point load, based on the ratio of the radius of contact area of the load to the radius of relative stiffness. Design flexural capacity obtained from ACI 360R-10 was smaller than that from TR 34 (2003 & 2013). In addition, TR 34 (2013), which evaluates the design flexural capacity based on the residual flexural strength, showed slightly smaller value than TR 34 (2003).

• Journal of Korean Society of Forest Science
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• v.12 no.1
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• pp.23-29
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• 1971

In order to see a possible strengthening of much injection of synthetic resin into timber by way of electric osmosis, Authors examined the change of the bending strength of the sample timber piece after being injected. 1. Three kinds of sample tree species, Pinus rigida, Magnolia and Populus were used and the size of the sample timber pieces was $30mm{\times}30mm{\times}330mm$. 2. Each of the electric osmosis was made with 250V of D. C. voltage and $0.01A/cm^2$ of the current for 2 hours and the experimenter hardened the injected resin by putting the sample in an oven of $120^{\circ}{\pm}2^{\circ}C$ temperature for 24 hours. 3. The size of the test sample piece for bending strength measurement was $20mm{\times}20mm{\times}320mm$ and Amsler type universal timber test machine was used for the measurement. 4. The strength difference between treated and untreated samples was as follows. Pinus rigida high sig. Magnolia None Sig. Populus Sig.