• 대한토목학회논문집
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• 제32권5A호
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• pp.299-305
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• 2012

본 연구는 수용성 폴리머의 일종인 폴리비닐아세테이트(Polyvinyl Acetate, 이하 PVAc)를 사용한 폴리머 시멘트 모르타르와 콘크리트의 특성에 관한 평가를 통하여 친환경 콘크리트 개발을 위한 기초자료를 획득하는 것이다. 이를 위해 PVAc를 혼입하지 않은 시멘트 모르타르 및 콘크리트와 결합재 대비 3%, 6%, 9%, 12%의 PVAc를 각각 혼입한 폴리머 시멘트 모르타르 및 콘크리트와의 비교분석을 통한 물리적 특성을 평가하였으며, 폴리머 혼입에 따라 늘어나는 공기량을 제어하기 위해 소포제를 첨가하여 PVAc 콘크리트의 특성을 평가하였다. 그 결과 PVAc가 혼입된 폴리머 시멘트 모르타르의 경우 압축강도는 낮아지나 휨강도와 건조수축의 성능이 향상되는 것으로 나타났으며, 콘크리트의 경우 혼입율이 6%일 때가 압축강도, 인장강도, 휨강도 및 탄성계수가 높아지는 것을 확인할 수 있었다.

• Tribology and Lubricants
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• 제38권2호
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• pp.41-52
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• 2022

Mineral electrical insulating oil, which is widely used in transformers, exhibits excellent cooling performance and transformer efficiency. However, given that it is composed of petroleum-based components, it is weak in terms of biodegradability. This causes environmental problems in case of leakage and a low flash point, which is a factor that would cause great damage in the event of a fire in a substation. In this context, the use of eco-friendly electric insulating oil composed of bio-based vegetable oil and synthetic ester, which has excellent biodegradability and flame retardancy performance, has recently been expanded to the field of electric power, and various research and development (R&D) studies are in progress. According to different research results, vegetable oil and synthetic ester manufacturing technology, thermal stability, oxidation stability, property change, and quality control, which are characteristics of eco-friendly electrical insulating oils, are major factors affecting the maintenance of insulating oil properties. In addition, power companies have established and operated quality control standards according to the use of eco-friendly electrical insulating oil as they expand the exploitatoin of renewable energy in electricity production. In particular, deterioration and oxidation characteristics were jointly identified in R&D as an important influencing factor according to the content of saturated and unsaturated fatty acids present in vegetable oils and synthetic esters in power transformer applications.

• 한국초지조사료학회지
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• 제44권1호
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• pp.50-57
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• 2024

Silage inoculants, crucial in modern silage production, comprise beneficial microorganisms, primarily lactic acid bacteria (LAB), strategically applied to forage material during ensiling. This study aimed to compare the effectiveness of various inoculants produced by different companies. Five treatments were evaluated, including a control group: T1 (Lactobacillus plantarum), T2 (Lactobacillus plantarum + Pediococcus pentosaceus), T3 (Lactobacillus plantarum + Pediococcus pentosaceus + Lactobacillus buchneri), T4 (Lactobacillus plantarum + Lactobacillus acidophilus + Lactobacillus bulgaricus), and T5 (Lactobacillus plantarum + Pediococcus pentosaceus + Enterococcus faecium). Italian ryegrass was harvested at the heading stage and treated with these silage inoculants. Samples were collected over a 60-day ensiling period. Co-inoculation with L. plantarum and P. pentosaceus (T2) resulted in significantly higher CP compared to the control group co-inoculation exhibited with resulted in Lactobacillus plantarum and Pediococcus pentosaceus in the T2 treatment exhibited higher CP content of 106.35 g/kg dry matter (DM). The T3 treatment, which included heterofermentative bacterial strains such as Lactobacillus buchneri, exhibited an increase in acetic acid concentration (11.15 g/kg DM). In the T4 treatment group, which utilized a mixed culture of Lactobacillus acidophilus and Lactobacillus bulgaricus, the NH₃-N/TN content was observed to be the lowest (20.52 g/kg DM). The T5 containing Enterococcus faecium had the highest RFV (123) after 60 days. Expanding upon these findings, the study underscores not only the beneficial effects of particular inoculant treatments on silage quality but also underscores the potential of customized inoculation strategies in maximizing nutrient retention and overall silage preservation.

• The Plant Pathology Journal
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• 제29권1호
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• pp.1-9
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• 2013

Plants are attacked by various phytopathogenic fungi. For many years, synthetic fungicides have been used to control plant diseases. Although synthetic fungicides are highly effective, their repeated use has led to problems such as environmental pollution, development of resistance, and residual toxicity. This has prompted intensive research on the development of biopesticides, including botanical fungicides. To date, relatively few botanical fungicides have been registered and commercialized. However, many scientists have reported isolation and characterization of a variety of antifungal plant derivatives. Here, we present a survey of a wide range of reported plant-derived antifungal metabolites.

• 열처리공학회지
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• 제36권1호
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• pp.40-46
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• 2023

Controlled nitriding is a technology that controls the nitriding potential based on the gas partial pressure received through an IOT-based sensor. Controlled nitriding is characterized by easy control of the phase of the nitride compound and excellent reproducibility of quality. In particular, it is possible to form a compound layer of excellent quality with fewer pores on the surface. However, despite these advantages, the application of controlled nitriding still needs to be improved in Korea. This paper explains the characteristics of controlled nitriding and describes the future direction and the problems of controlled nitriding in Korea.

• 한국구조물진단유지관리공학회 논문집
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• 제14권3호
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• pp.152-159
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• 2010

최근 친환경 재료와 구조물에 대한 관심이 증대되면서 친환경 재료인 황토에 대한 연구가 활발히 진행되고 있다. 황토는 건설 및 마감 재료로 사용된 전통적인 친환경 건설 재료 중의 하나이다. 황토는 높은 축열성, 습도 조절 능력, 자정력, 탈취 및 항균성능, 인체에 유익한 다량의 원적외선이 방사되는 점 등 건설 재료로서 많은 장점을 갖고 있다. 그러나, 황토는 낮은 강도특성과 건조수축 균열 특성 때문에 현대 건설에 사용되지 않고 있는 실정이다. 최근 연구자들의 연구결과에 따르면, 황토는 플라이 애쉬나 포졸란 같은 천연 포졸란 재료로 사용될 수 있다. 본 논문에서는 황토와 슬래그, 재생 PET 섬유가 혼입된 콘크리트의 역학적 성질과 구조적인 휨 거동 실험을 수행하였다. 실험 결과 황토콘크리트의 압축강도와 탄성계수는 기준 시멘트 콘크리트 시편보다 상대적으로 낮게 평가되었으며, 철근 콘크리트 보의 휨 거동은 거의 유사하게 나타났다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.65-65
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• 2015

In this talk, I will introduce two topics. The first topic is the polymer light emitting diodes (PLEDs) using graphene oxide quantum dots as emissive center. More specifically, the energy transfer mechanism as well as the origin of white electroluminescence in the PLED were investigated. The second topic is the facile synthesis of eco-friendly III-V colloidal quantum dots and their application to light emitting diodes. Polymer (organic) light emitting diodes (PLEDs) using quantum dots (QDs) as emissive materials have received much attention as promising components for next-generation displays. Despite their outstanding properties, toxic and hazardous nature of QDs is a serious impediment to their use in future eco-friendly opto-electronic device applications. Owing to the desires to develop new types of nanomaterial without health and environmental effects but with strong opto-electrical properties similar to QDs, graphene quantum dots (GQDs) have attracted great interest as promising luminophores. However, the origin of electroluminescence (EL) from GQDs incorporated PLEDs is unclear. Herein, we synthesized graphene oxide quantum dots (GOQDs) using a modified hydrothermal deoxidization method and characterized the PLED performance using GOQDs blended poly(N-vinyl carbazole) (PVK) as emissive layer. Simple device structure was used to reveal the origin of EL by excluding the contribution of and contamination from other layers. The energy transfer and interaction between the PVK host and GOQDs guest were investigated using steady-state PL, time-correlated single photon counting (TCSPC) and density functional theory (DFT) calculations. Experiments revealed that white EL emission from the PLED originated from the hybridized GOQD-PVK complex emission with the contributions from the individual GOQDs and PVK emissions. (Sci Rep., 5, 11032, 2015). New III-V colloidal quantum dots (CQDs) were synthesized using the hot-injection method and the QD-light emitting diodes (QLEDs) using these CQDs as emissive layer were demonstrated for the first time. The band gaps of the III-V CQDs were varied by varying the metal fraction and by particle size control. The X-ray absorption fine structure (XAFS) results show that the crystal states of the III-V CQDs consist of multi-phase states; multi-peak photoluminescence (PL) resulted from these multi-phase states. Inverted structured QLED shows green EL emission and a maximum luminance of ~45 cd/m2. This result shows that III-V CQDs can be a good substitute for conventional cadmium-containing CQDs in various opto-electronic applications, e.g., eco-friendly displays. (Un-published results).

• 식물병연구
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• 제23권4호
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• pp.334-347
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• 2017

Ralstonia solanacearum에 의한 고추 풋마름병은 고추의 생산량 감소에 영향을 미치는 주요 병해 중 하나이다. 그리고 병 저항성 작물을 재배하는 것은 고추의 풋마름병 방제에 가장 효과적인 방제 방법이다. 본 연구는 고추의 풋마름병 저항성을 효율적으로 검정하기 위한 방법을 개발하기 위하여 수행되었다. 풋마름병에 대한 저항성 및 감수성 6개 고추 품종을 선발하고, 다양한 조건에서 이들 품종의 풋마름병 발생을 조사하였다. 접종 방법에 따른 고추 품종들의 풋마름병 발생 정도를 실험한 결과, 상처없이 토양관주하는 방법과 접종원에 뿌리를 침지하는 방법보다 뿌리 절단 후 접종원을 관주하는 방법이 더 간단하고 효율적이었다. 풋마름병 저항성 계통인 'MC4'는 파종 후 21일부터 28일 재배한 고추 유묘에 $1{\times}10^8cfu/ml$ 농도의 세균 현탁액을 포트 당 20 ml 접종하였을 때 가장 높은 저항성을 나타냈다. 한편 감수성 품종들은 이들 조건에서 높은 감수성을 보였다. 이들 결과는 우리가 고추 품종의 풋마름병에 대한 효율적인 저항성 검정방법을 개발하였다는 것을 나타낸다. 그리고 선발한 발병조건을 사용하여 시판중인 140개 고추 품종의 풋마름병에 대한 저항성 정도를 평가하였다.

• 한국유기농업학회지
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• 제25권3호
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• pp.631-642
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• 2017

작물의 재배 과정 중에 발생하는 해충을 효과적으로 방제하기 위하여 친환경 유기농자재, 미생물 살충제, 화학 살충제와 같은 다양한 방제제가 사용되고 있다. 이들은 다양한 해충과 병을 방제하기 위해 동일한 포장에서 동시에 또는 순차적으로 이용된다. 이 방제제들은 서로 영향을 미쳐 방제 효과도 달라질 수 있다. 따라서 미생물 살충제와 동시에 또는 동일 포장에 처리될 수 있는 다른 농자재의 혼용가능 여부를 조사할 필요가 있다. 따라서 본 연구에서는 시설하우스에서 가루이류 방제를 위해 등록된 친환경 유기농자재의 전처리가 담배가루이 방제를 위해 개발된 Isaria javanica 균주의 포자 발아, 균사 성장 그리고 방제효율에 미치는 영향을 조사하였다. 그 결과, 담배가루이 방제용으로 국내에서 개발된 I. javanica 균주는 4종(A, 파라핀오일+계피오일; B, 대두유; C, 님추출물+참깨오일; D, 채종유)의 가루이류 방제용 친환경 살충제 중 A 살충제에 의해 포자 발아($8.9{\pm}1.3%{\sim}24.5{\pm}0.9%$) 및 균사 성장($0.81{\pm}0.01cm{\sim}0cm$)이 감소되었다. 담배가루이 방제에서 친환경 유기농자재와 I. javanica 사이의 처리 간격이 미치는 효과 조사를 위해, 친환경 유기농자재 4종을 I. javanica 균주 처리 0, 1, 4, 7일 전 처리하고 방제 효과를 조사하였다. 친환경 유기농자재 전처리는 4종 모두 I. javanica의 담배가루이 방제효과를 감소시켰다. 따라서 국내에 등록된 가루이류 방제용 친환경 유기농자재 4종과 개발된 곰팡이 살충제 I. javanica를 동시에 또는 순차적으로 이용할 경우, 상호영향을 고려하여 7일 이상의 간격을 두고 살포하는 것이 효과적으로 담배가루이를 방제 할 수 있을 것으로 사료된다.

• 한국자원식물학회지
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• 제19권6호
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• pp.721-726
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• 2006

Mosquitoes are carriers of malaria and encephalitis. This study performed for eco-friendly control of mosquitos by using genus Acorus. Several solvents were used for the extraction of genus Acorus; water, ethanol, and methanol. Grinded leaves and roots were also included. Acorus extracts killed mosquito larvae and the ethanol extract showed the best result. Autoclaved Acorus water needed long time to kill mosquito larvae. $LT_{50}$ of 1 % Acorus calamus decoction was 13.6 hrs and 1 % autoclaved Acorus water was 53.6 hrs. $LT_{50}$ of 0.05% Acorus calamus rhizome powder was 28.5 hrs. $LT_{50}$ of 0.5% Acorus calamus leaf powder was 10.8 hrs. $LT_{50}$ of 0.1 % Acorus calamus decoction was 63.4 hrs and 0.1 % Acorus calamus ethanol extracts was 48.6 hrs and 0.1% Acorus calamus methanol extracts was 53.9 hrs. $LT_{50}$ of 0.4% Acorus gramineus decoction was 45.5 hrs, 0.4% ethanol extracts was 10.9 hrs, 0.4% methanol extracts was 10.2 hrs. $LT_{50}$ of ethanol extracts was shorter than other extracts. Acorus calamus rhizome powder could be used for the eco-friendly control of the mosquito larvae.