• Journal of Applied Biological Chemistry
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• v.52 no.4
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• pp.195-199
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• 2009

To select antifungal surfactants, control efficacy of various nonionic and anionic surfactants on cucumber powdery mildew was evaluated under greenhouse conditions. Among 14 surfactants, pentaetylene glycol monododecyl ether ($C_{12}E_5$), mixture of heptaethylene glycol monodecyl ether and heptaethylene monododecyl ether, and heptaethylene glycol mono-9-octadecenyl ether effectively reduced the development of powdery mildew on cucumber plants. Among the surfactants, $C_{12}E_5$ gave the best control efficacy on the disease and did not show phytotoxic response in cucumber plants. Whereas, fenarimol at a recommended rate (31.3 mg/L) showed less control activity than the surfactant (1,000 mg/L). In addition, mixtures of the surfactant and DBEDC, a protective fungicide, showed high control efficacies against powdery mildews of cucumber and strawberry by additive effect in greenhouse tests.

• Resources Recycling
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• v.15 no.2 s.70
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• pp.32-36
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• 2006

Magnesium has been used as light and functional material, and its demand is increasing as a material for automobile engine and for mobile phone or notebook PC case. Fused salt electrolysis and thermal reduction are regarded as main methods for the extraction of magnesium, and choice for the method is firstly according to raw material. In this study, magnesium metal is obtained by an electrolysis of magnesium chloride. Two types of fused salt mixtures were used as electrolyte and electrolyzed at 7V with a graphite anode having the same depth, and their results were compared with each other. A mixed salt of $KCl/NaCl/MgCl_2$ was the more effective than $KCl/NaCl/CaCl_2/CaF_2/MgCl_2$ in current efficiency through the experiments at $760^{\circ}C$. Purity of the prepared magnesium metal was above 98%. Some basic data for scale-up of the magnesium electrolysis equipment, which would be necessary for a commercialization, could be obtained.

• Journal of Digital Convergence
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• v.16 no.10
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• pp.27-37
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• 2018

The purpose of this study is figure out secondary education undergraduates' communication patterns and perceptions of use in KAKAOTALK, one of the most frequently used Social Network Service(SNS). The mixed method research was conducted of survey about 86 students and in-depth interview 10 of them. The chief implication of research showed that it has been firstly functioning them to sustain public and private network and to be an universal tool of expression their opinion, idea, themselves, however, they still regard face-to-face communication important. Secondly, they think that KAKAOTALK is a part of their everyday lives and regarded a communication space to freely express themselves and to adjust and manage their image. Thirdly, they psychologically solved their loneliness and were encouraged, moreover, the contents of communication were different according to usd of public or private team chat room. It needs a follow-up study comparatively to analyze other generation's cognitive psychological values in SNS and to suggest digital culture literacy guideline.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.33-42
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• 2020

This study analyzed the bicycle traffic patterns and identified the influence factors for each traffic purpose using the household traffic conditions survey for Seoul. The results are summarized as follows. First, as a result of surveying the bicycle traffic ratios according to the administrative dongs, there was a difference of 14.2% by region. Second, various personal characteristic variables, such as age, gender, income, occupation, and housing type, affect the bicycle mode choice, and bicycle passage increases when using facilities in residential areas. Third, among the neighborhood environments, the bicycle traffic for commuting purposes appeared to increase more in the areas of higher land use mix and lower crime rates. In addition, the bicycle road density and the inclination of the area commonly affect bicycle travel for commuting, shopping, exercising, and leisure.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.2
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• pp.42-54
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• 2021

The Aft-deck is being applied to the latest unmanned aircraft for the purpose of shielding the gas turbine exhaust plume or spreading jets to increase the mixing rate with the ambient air, thereby reducing the temperature of exhaust gases. In this study, we would like to find out how the performance of the nozzle is affected by the design variables of the Aft-deck. The design variables of aft-deck are selected as length, expansion angle and upper deck shape. The correlation between thrust and plume shielding rate with the length variable is presented. And the correlation between the thrust and the jet diffusion range is presented according to the expansion angle. In addition, the thrust increase effect is confirmed by the removal of the upper deck and the characteristics of transverse velocity vector determined mixing performance with external flow.

• Journal of the Korea Concrete Institute
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• v.17 no.2 s.86
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• pp.263-271
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• 2005

HPFRCC(High Performance Fiber Reinforced Cementitious Composite) is a class of FRCCs(Fiber Reinforced Cementitious Composites) that exhibit multiple cracking. Multiple cracking leads to improvement in properties such as ductility, toughness, fracture energy, strain hardening, strain capacity, and deformation capacity under tension, compression, and bending. These improved properties of HPFRCCs have triggered unique and versatile structural applications, including damage reduction, damage tolerance, energy absorption, crack distribution, deformation compatibility, and delamination resistance. These mechanical properties of HPFRCCs become different from the kinds and shapes of used fiber, and it is known that the effective size of fiber in macro crack is different from that in micro crack. This paper reports an experimental findings on the mechanical properties of HPFRCCs reinforced with the micro fiber(PP50, PVA100 and PVA200) and macro fiber(PVA660, SF500). Uniaxial compressive tests and three point bending tests are carried out in order to compare with the mechanical properties of HPFRCCs reinforced with micro fibers or hybrid fibers such as compressive strength, ultimate bending stress, toughness, deformation capacity and crack pattern under bending, etc.,

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.3
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• pp.225-233
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• 2019

This study was conduct to investigate the effect of mixed seed sowing and flour blending on the uniformity of flour quality of Korean domestic wheat. Two wheat varieties (Keumkang and Baegjoong) were selected for sowing mixed seeds, and their growth characteristics and flour quality were analyzed. Quality of flour blending with the same varieties was also evaluated. The ratios for mixed seed sowing and flour blending were from 0 to 100% with a 10% increase of interval for each treatment. On increasing the portion of Baegjoong in mixed seed sowing, the heading time was a little delayed, however, yield increased. The results of the flour quality showed lower damaged starch content and sodium carbonate SRC (solvent retention capacity) value for Keumkang than for Baegjoong. Protein quantity by protein content and quality by SDSS (Sodium Dodecyle Sulfate-Sedimentation) volume, lactic acid SRC, and mixograph pattern of Keumkang were superior to those of Baegjoong. Compared with mixed seed sowing, overall quality characteristics of flours with different ratios showed predictable and proportional change by flour blending. This demonstrated the successful application of flour blending, compared with mixed seed sowing, for improving the uniformity of flour quality.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.204-204
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• 2016

다양한 형태의 대기압 저온 플라즈마 장치를 개발하고 특성을 연구하였다. 최근 대기압 저온 플라즈마를 의료 및 미용 분야에 적용하기 위한 연구가 활발하게 진행되고 있다. 본 연구에서는 대기압 플라즈마 장치의 생체 적용을 위해 전기적, 열적 피해가 없는 플라즈마 발생 장치를 개발하였다. 대기압 플라즈마 발생 장치는 크게 플라즈마 제트와 유전 격벽 방전(DBD) 플라즈마의 형태로 나눌 수 있다. 대기압 플라즈마 제트는 고압 전극의 역할을 하는 주사 바늘과 바늘을 감싸고 있는 유리관, 유리관의 외부에 위치하는 접지 전극의 구조로 되어 있다. 방전 기체는 방전이 용이한 불활성 가스가 주로 사용되지만, 필요에 따라 $N_2$나 Air같이 방전이 어려운 분자 및 혼합 기체도 사용 한다. 방전 기체에 따라 대기압 플라즈마 제트의 전극 구조를 다르게 적용하였으며, 각 구조에서의 플라즈마 방전 특성을 연구 하였다. 유전 격벽 방전 플라즈마 장치는 고압 전극과 접지 전극 사이에 유전체가 위치하는 구조이다. 방전 가스를 불어주지 않아도 대기중에서 방전이 가능하고, 구조가 간단하여 용도에 맞는 다양한 형태로 방전이 가능하다. 이러한 대기압 저온 플라즈마의 특성 연구를 바탕으로 전기적, 열적 피해가 없으며 사용자 편의성을 갖춘 다양한 형태의 대기압 플라즈마 장치를 개발 하였다. 본 연구를 통하여 대기압 저온 플라즈마 발생 장치의 개발과 활용 연구에 도움이 될 것으로 기대한다.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.125.1-125.1
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• 2015

산업 자동화기술이 발달함에 따라 다양한 용도의 부품개발과 산업 장비들의 부품에 대한 수요가 날로 증가하게 되어 산업이 발달하게 된 반면, 장비의 성능을 저하시키는 마모에 대한 문제점이 제기되고 있다. 이에 대한 해결책으로 내열성 및 내마모성을 가지는 박막코팅기술이 요구되고 있다. 특히, Alumina (Al2O3)와 Zirconia (ZrO2)는 내식성과 내열성, 내마모성의 우수한 특성을 지닌 재료이며, 이들을 기어, 베어링, 실린더 등 각종 기계의 부품에 코팅하여 내마모성을 가지게 한다. 본 실험에서는 Al2O3 : ZrO2 = 50 : 50 wt% 의 비율로 혼합한 target이 사용되었다. 그리고 Al2O3-ZrO2 target을 사용하여 RF-magnetron sputtering 방법으로 박막을 제작 하였다. sputter시에 power를 20 W에서 80 W까지 변화를 주었다. AFM, SEM, XRD를 통하여 알루미늄 기판위에 증착된 Al2O3-ZrO2 박막의 구조적 특성을 알아보았으며, 내마모성 테스트 장비를 통하여 박막의 마찰마모 특성에 대하여 조사하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.487-490
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• 2005

The thrust Control in Solid Propellant Rocket is incomparably limited than that in Liquid Propellant Rocket. Because it is fixed that section to relate a combustion, that is a natural result. The control of a thrust directions in a Solid Propellant Rocket is not efficient for the purpose of a Solid Propellant Rocket. But it is a problem to solve that a weight on board should increase through the maximization of the thrust in a Solid Propellant Rocket.