• Korean Journal of Soil Science and Fertilizer
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• v.37 no.1
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• pp.41-45
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• 2004

A phosphate solubilizig bacterium, Pantoea agglomerans, was isolated from rhizosphere soils collected from Chungbuk area. A greenhouse experiment was conducted to study the effect of combined application of rock phosphate and P. agglomerans inoculation on plant growth and phosphate accumulation of rice (Oryza sativa L.). Apart from control that received no inputs, six treatments were planned as follows; 1) seed bacterization, 2) free cell inoculation and 3) bacteria immobilized beads inoculation, individually and in combination with 1 and 2.5 g of rock phosphate per pot. The results showed that plant growth and phosphate uptake were significantly enhanced as a result of bacterial inoculation. Bacterial inoculation in the form of immobilized beads and 1 g of rock phosphate was found to affect positively the rice plant growth and phosphorus accumulation than other treatments. The available phosphate concentration of the pot mixture also found improved as a result of P. agglomerans inoculation. A positive correlation was observed between the phosphate concentration in the pot mixture and phosphate accumulation in plant.

• Analytical Science and Technology
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• v.26 no.2
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• pp.142-153
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• 2013

A new, rapid, and simple analytical method was developed and validated using high performance liquid chromatograph-photodiode array detector (HPLC-PAD) for the determination of lepimectin residues in agricultural commodities. The lepimectin residues in samples were extracted with methanol, partitioned with dichloromethane, and then purified with glass column filled with subsequently to aminopropyl ($NH_2$) solid phase extraction (SPE) cartridge. The purified samples were detected using HPLC-PAD. Correlation coefficient ($R^2$) of both lepimectin $A_3$ and $A_4$ solutions were 0.9999. The method was validated using cucumber spiked with lepimectin at 0.02 and 0.2 mg/kg and pepper, mandarin, hulled rice, potato, soybean at 0.02 and 0.5 mg/kg. Average recoveries were 76.0~114.8% with relative standard deviation less than 10%, and limit of detection (LOD) and limit of quantification (LOQ) were 0.005 and 0.01 mg/kg, respectively. The result of recoveries and overall coefficient of variation of a laboratory results in Gwangju regional KFDA and Daejeon regional KFDA was followed with Codex guideline (CAC/GL 40). Therefore, developed method in this study is accurate, rapid, and appropriate for lepimectin determination and will be used to keep safety of lepimectin residues in agricultural products.

• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.157-162
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• 1988

In order to study of practical purpose of immobilized Mucor spp L42 milk clotting enzyme on activated succimylamino-propyl glass beads with glutaraldehyde in continuous curd coagulation, acidified milk(pH5.6, $8^{\circ}C$) was treated through reactor packed with immobilized beads, and warmed at $30^{\circ}C$ and allowed to coagulation for the determination of enzyme stability, deactivation of milk clotting ability by continuous reaction, the beads treatment conditions, and contact time of milk and beads in reactors. The results obtained were summarized as follow ; 1) After 3 month's storage, activity of immobilized Mucor spp L42 milk clotting enzyme in 0.2M phosphate buffer(pH 4.6) with 0.06% sodium azide was only 80% of initial activity. 2) Milk clotting activity of the beads was decreased by continuouse exposure on acidified skim milk. Nitrogen accumulation on the beads paralled loss of the activity in initial reaction stage. 3) After 6 hours continuous treatment of the beads at 60 sec/ml surface time, the milk-clotting activity of the beads was about 70% of initial activity. 4) Bead reactor and shaking bed reactor were more effective than column reactor on continuouse skim milk coagulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.662-669
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• 2017

Military rotary aircraft are heavily exposed to projectile environments due to their mission characteristics, and fires caused by fuel leaks after shooting are linked directly to the loss of human life. To improve the survivability of pilots and crews, the fuel tank in rotary aircraft must have gunfire resistance and anti-explosion characteristics. Gunfire resistance can be satisfied by applying a self-sealing cell to a fuel tank. Anti-explosion can be satisfied by reducing the oxygen concentration in an explosive area and suppressing the generation of combustible fuel vapor by minimizing the evaporation rate of the fuel by heat. A Korean utility helicopter applies anon-board inert gas generation system to meet the anti-explosion requirements for ballistic impact. The generator fills the fuel tank with an inert gas and reduces the oxygen concentration. This paper describes the overall development process of the OBIGGS developed in accordance with the localization process of weapon components. OBIGGS was developed/manufactured through domestic technology, and the performance was found to be equal to or better than that of the existing products through single performance tests and aircraft mounting tests.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.7
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• pp.418-425
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• 2015

Anaerobic Filters (AF) packed with porous ceramic floating media were operated at different operational conditions to identify the feasibility of the renewable bioenergy, methane production from swine wastewater and to verify the suitability of effluent from anaerobic filters for the subsequent biological nitrogen and phosphorus removal. Stepwise increase in organic loading rates (OLRs) or decrease in hydraulic retention times (HRTs) with influent TCOD concentration of 14,000 mg/L were utilized at mesophilic temperature. The maximum methane productivity of 1.74 volume of $CH_4$ per volume of reactor per day (v/v-d) was achieved at an hydraulic retention time (HRT) of 0.5 day (OLR 28 g TVS/L-d). Based on the biogas production, the highest total volatile solids (TVS) removal efficiency of 63% was obtained at an HRT of 3 days (OLR 4.67 g TVS/L-d), however based on the result from the effluent total chemical oxygen demand (TCOD) analysis, the highest TCOD removal efficiency of 75% was achieved. The effluent alkalinity concentration over the range of 2,050~2,980 mg/L as $CaCO_3$ at all operational conditions, could compensate the alkalinity destruction caused by nitrification. The effluent from the anaerobic filter operated under the HRT of 2 days showed the COD/TKN ratio of 15~35 and COD/TP ratio of 38~56. Therefore effluent C/N/P ratio is able to satisfy the optimum COD/TKN ratio of greater than 8.0 and COD/TP ratio of 33 for the subsequent biological nutrient removal.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.4
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• pp.57-65
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• 2003

Livestock farming is one of several industries that have faced criticism because of its impact on the water quality, soil contamination and air pollution. The livestock feces can cause some environmental problems. The best way to treat the feces is to recycle the manure as an organic fertilizer after fermentation or composting. This study was carried out to investigate the characteristics of composting of manure in several composting conditions. The variations of physicochemical characteristics of each compost piles containing different level of air volume were analyzed throughout the composting period. In this study, pigs manure compost piles mixed with saw dust were composted in 110L of laboratory scale plastic vessels and $1.5m^3$ of small cubic wooden composting vessels for 60days. The compost piles were ventilated continuously with air pump throughout the composting duration. The air volume ventilated into the piles was regulated by chock valve attached to the inlet pipe. The ventilation level was adjusted by 20, 50, 100, 150 and $200L/m^3/mim$, respectively. The highest temperature of the compost increased to $72^{\circ}C$ during composting period. After 20days from beginning of fermentation, concentrations of $H_2S$, $CH_3SH$, DMS and DMDS generated from compost piles were 29, 16, 6 and 5ppb in blow in state compost pile, conversely, in blow out state compost pile, the parameters were 32, 24, 15 and 14ppb, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.209-214
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• 2017

Most of the present potential transformers of train vehicles are of the oil-type filled with insulating oil and are susceptible to problems such as explosion due to the increase in the internal pressure during train operation and poor reliability near the end of their life cycle. As a solution to this problem, it is necessary to develop a molded dry-type potential transformer with excellent pressure-resistance performance using insulating resin. In order to localize the product, the Korea Railroad Research Institute has been developing a molded dry-type potential transformer. As part of this research, it is necessary to analyze the vibration characteristics of the developed product and to check the transformer performance in a vibration environment. In this study, a resonance test and simulated long-term life test of the developed product were conducted according to the KS R 9144 and IEC 61373 standards, respectively, which are vibration test methods for railway vehicle parts. Their natural frequencies were analyzed by comparing the results of the numerical modal analysis and resonance test, in order to confirm their adherence to the standards. Also, the performance test after the simulated long-term life test confirmed that the operation of the developed transformer was not problematic even in a long-time vibration environment.

• Korean Journal of Plant Resources
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• v.26 no.1
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• pp.75-83
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• 2013

The present study was examined seed germination and growth characteristics of Cynanchum wilfordii under the following conditions such as soaking temperature, concentrations of $GA_3$, trays and soil types, and shading conditions. In seed pre-treatment, germination rate was the highest at 93% when soaked in 100 ppm $GA_3$ at $20^{\circ}C$ and seedling growth was best in 50 plug cell tray. Physiological quality was best in the condition in which seeds were treated with 10 ppm $GA_3$ at $20^{\circ}C$. Taking into consideration the seedling growth, their physiological quality as well as economical aspects, seedlings with plant height (over 10 cm) and root length (over 10 cm) were grown vigorously 30-45 days after the seeds were sown in mid-April in TKS, TKS+perlite and TKS+rice hull of 128 or 200 plug cell tray.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.40-40
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• 2018

비고사리과(Lindsaeaceae) 버들일엽[Laxqgramme saliciblia (Makino) Makino]은 잎이 녹색의 단엽으로 버들처럼 보여 관상가치가 높아 조경소재로 이용되는 착생식물이다. 또한 식물구계학적 특정식물종 V급, 적색자료집 VU급, 국외반출 승인대상종에 수록된 식물로 생태학적 보전이 요구되며, 개체수도 적은 편으로 알려져 있다. 본 연구는 보전이 요구되는 버들일엽의 전엽체 증식 및 포자체 형성을 위한 기내 외 번식조건을 구명하고자 수행되었다. 서귀포시 상효동 일대에서 식물을 획득하였으며, 기내에서 포자를 발아시켜 획득한 전엽체를 8주 간격으로 계대배양하면서 실험재료를 확보하였다. 전엽체 증식에 적합한 배양배지를 선발하고자, 전엽체 300mg을 다진 후 배지종류와 농도를 달리한 배지(Knop, 1/4, 1/2 및 1MS)에 8주간 배양하였다. 배양실은 온도 $25{\pm}1.0^{\circ}C$, 광도 $30{\pm}1.0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$(16/8h)로 조절되었다. 연구의 결과, 1/2MS배지에서 전엽체의 생체중이 5.8g으로 가장 많이 증가하였으며, 형태형성의 발달도 주걱형의 전엽체로 정상적으로 발달하였다. 기외 포자체 형성에 적합한 토양조건을 확인하고자, 인공토양(원예상토, 피트모스, 펄라이트 및 마사토)의 비율을 달리하여 5종류의 혼합토양을 조성하였다. 준비된 토양을 사각분($7.5{\times}7.5{\times}7.5cm$)에 충진하고, 전엽체 1g을 10초간 분쇄한 다음 토양표면에 분주하여 16주간 재배하였다. 재배환경은 온도 $25{\pm}1.0^{\circ}C$, 광도 $43{\pm}2.0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$(16/8h) 및 습도 $72{\pm}2.0%$로 조절되었다. 연구의 결과, 원예상토가 많은 비율로 혼합된 처리에서 포자체의 형성이 확인되었다. 원예상토와 펄라이트를 2:1(v:v)로 혼용한 토양, 원예상토와 마사토를 2:1(v:v)로 혼용한 토양, 원예상토 단용한 토양에서 각 28.5, 23.0, 22.3개로 조사되었다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.59-59
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• 2018

갯까치수염은 앵초목 앵초과의 두해살이풀로 지상부가 고사하지 않고, 월동 후 봄까지 뚜렷한 윤기가 흐르는 잎을 가지며, 7~8월에 흰색 꽃이 피는 관상성이 뛰어난 우리나라의 자원식물이다. 이에 신 관상소재로서의 품목개발을 위해 관상 및 조경산업용 가치가 큰 갯까치수염의 지피용 작물로서의 재배효과를 확인하기 위하여 2017년 7월 31일부터 10월 9일까지 약10주간 실험하였다. 이식묘의 소질별 생육효과, 기비의 시비와 혼합상토의 조성 및 포트의 크기 등의 이식조건, 차광처리 및 추비시비 등 재배관리에 대한 효과를 조사하였다. 종자로 육묘한 이식묘의 소질로서는 200구 트레이에서 한 cell 당 2립씩 파종된 유묘가 지피용 갯까치수염의 재배에 적합하였다. 이식조건으로 코트비료의 기비는 하지 않고, 마사토:피트모스(3:1) 혼합 용토에 $300-200-200mg{\cdot}L^{-1}$(N-P-K)의 비료분을 첨가한 토양을 충진한 4인치 포트에 이식하는 것이 생육에 가장 효과적이었다. 재배관리에는 차광처리를 하지 않고 배치하는 것이 50 및 70% 차광처리보다 초장, 엽수, 엽면적, 생체중 및 건물중 등 생육에 효과적이었다. 또한, $500mg{\cdot}L^{-1}$ hyponex 추비처리를 한 것의 엽수가 36매로 다른 처리의 15~26매 보다 많았지만, 엽면적 및 생체중을 고려할 때 지피식물로서 10주간의 재배를 위해서는 추비하지 않는 것이 적합할 것으로 생각된다.