• 대한지리학회지
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• 제39권4호
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• pp.544-561
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• 2004

본 연구에서는 대관령 지역의 산림 및 농경지 소유역을 대상으로 주 1회의 유량 및 수질 조사를 실시하고 유량 및 수질 항목간의 상관관계를 분석하였다. 산림 소유역의 수질 변화는 적었던 반면 농경지 소유역에서는 화학비료 및 가축분 퇴비의 시용과 토양 유실로 인해 큰 폭의 수질 변화를 보였다. 용존산소량(DO)은 두 소유역에서 유량보다는 수온과 매우 뚜렷한 음의 상관관계를 나타냈다. 산림 소유역에서는 농경지 소유역에 비해 유량과 총질소(T-N) 및 $K^{+}$의 양의 상관관계가 뚜렷하게 나타났다. 반면, 농경지 소유역에서는 부유물질 총량(TSS), 총인(T-P) 및 화학적 산소요구량(COD)이 유량과 높은 상관성을 보였다. 대관령 지역에서는 도암호의 수질 오염, 특히 T-P의 증가가 심각하다는 점에 비추어 볼 때 수질 개선을 위해서는 농경지의 토양 유실 방지가 매우 중요하다. 특히 고랭지 채소 파종기에 해당하는 6월말에서 7월초에 이르는 기간의 토양 및 양분유실이 가장 심각한 것으로 나타나 이를 줄이기 위한 친환경농법 도입이 요구된다.

• 한국물환경학회지
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• 제31권6호
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• pp.715-722
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• 2015

Four major river basin in Korea has been managed with Total Maximum Daily Load(TMDL) System. Water quality indicators as targeted pollutants for TMDL were BOD and TP. In order to satisfy water quality criteria, government allocation using public treatment facilities and its action plan has been used. However, the role to improve water quality were recently faced to its limitation. It is time to require the role of non-government allocation in private discharge facilities to control good water quality. This study investigated three different scenarios in reduction demands of non-government allocations about industry and private sewages. The three different scenarios were discharge under 1) legal water quality standard, 2) water quality level in 2011 and 3) current water quality level with maximum value in group. The results showed that reduction potential in water discharge for TP indicator was 1,118kg/day, under second scenario with 20% of deduction. This results arrived at 42% of whole reduction potential costs and 0.012mg/L improvement in water quality. In conclusion, to intrigue voluntary participation in non-government allocation, various benefits such as tax reduction, tax exemption, and water quality trading should be provided.

• 동력기계공학회지
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• 제14권1호
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• pp.27-33
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• 2010

We investigate some operation characteristics and energy efficiency of the BLDC motor system driven by different two types power conversion method depends on same battery source for applying to electrical motor propulsion system of a small ship. Also, we suggest an estimation manner of operating performances such as total running distance and operating speed of ships from basic discharge voltage characteristics of batteries. Through some experiments, direct power conversion was better than indirect method on the view point of energy efficiency and the voltage discharge characteristics could be used as important design factor for estimating operating performances of small ships driven by electrical motors.

• 한국농공학회지
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• 제43권6호
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• pp.163-173
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• 2001

This study describes the characteristics of concentrations of pollutants such as total nitrogen(T-N), total phosphorous(T-P), and chemical oxygen demand(COD) at paddy areas during 2-year irrigation periods. The most common order in average concentrations of T-P and COD is podded water > irrigation(or drainage) water > percolated water. Most of pollutants concentrations in drainage water are lower than those in irrigation water after early July due to large uptake of pollutants by rice crop and denitrification. The exponential L (load)-Q(discharge) equations for classified irrigation periods are significant at 0.001 level for irrigation and drainage waters. For drainage water, the concentrations of T-N and COD slightly decrease with discharge, while the T-P concentrations slightly increase with discharge.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.171-174
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• 2005

Experimental measurements are reported and compared with the results of a two-dimensional fluid simulation for the investigation of the discharge characteristics regarding the change of the mixture ratio of Ne-Xe-He noble gases. The increase of Xe contents results in the increases of luminance and luminous efficiency while it also results in the increase of the breakdown voltage and the discharge time lag. The addition of He gas increases the brightness and the luminance efficiency. When Xe partial pressure is low, the luminance efficiency increases with the amount of He at the same total pressure. When Xe partial pressure is high, however, the luminance efficiency has a maximum value when the partial pressure of He is about 10% of the total pressure for a standard AC PDP cell with Xe fraction of $10{\sim}30%$.

• 도시과학
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• 제8권2호
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• pp.13-18
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• 2019

Using self-made coil dielectric barrier discharge reactor, the removal efficiency of ethyl acetate under simulated experimental parameters such as initial concentration of waste gas, total flow rate, relative humidity and voltage was investigated. The results show that the degradation rate of ethyl acetate increases with the increase of output voltage. When other conditions remain unchanged, the degradation rate decreases with the increase of initial concentration of ethyl acetate; with the increase of total flow rate, the degradation rate of ethyl acetate decreases; with the increase of relative humidity, the degradation rate first increases and then decreases, and when the relative humidity is 64%, the degradation efficiency is the highest.

• 열처리공학회지
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• 제25권2호
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• pp.80-84
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• 2012

An apparatus was constructed to nitrify small metallic sintered components by using a hollow-cathode discharge plasma method. A stainless steel basket, which contains a sintered part to be nitrified, is potentially grounded and serves as hollow-cathode electrode. Hollow-cathode plasma was produced by supplying the positive voltage to the anode. In this study sintered carbon iron and stainless steel were used as testing specimens. It was shown that an effective nitrifying took place by controlling the total pressure of nitrogen and hydrogen gas and applied voltage.

• 반도체디스플레이기술학회지
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• 제17권3호
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• pp.90-94
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• 2018

In this paper, we applied a three-level T-type inverter with the one more voltage level than two-level inverter. However, the three-level T-type inverter has a systematic problem with voltage unbalances. So neutral point control is essential. Therefore, the voltage unbalance problem of the three - phase inverter was confirmed to be controlled within 5V using the neutral point control algorithm in charge and discharge mode. In addition, total harmonic distortion was reduced in three phases (u phase, v phase, w phase) when neutral point control was performed in charging mode and also in three phases (u phase, v phase, w phase) in discharge mode. In this paper suggests a neutral point control algorithm to solve the voltage unbalance of a three-level T-type inverter, and shows the improvement of the performance of the proposed algorithm through experiment.

• 한국환경과학회지
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• 제32권3호
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• pp.197-204
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• 2023

This study aims to inactivate Artemia sp. (Zooplankton) in ballast water through the dielectric barrier discharge (DBD) plasma process. The DBD plasma process has the advantage of enabling direct electric discharge in water and utilizing chemically active species generated by the plasma reaction. The experimental conditions for plasma reaction are as follows; high voltage of 9-22 kV, plasma reaction time of 15-600 s, and air flow rate of 0.5-5.5 L/min. The results showed that the optimal experimental conditions for Artemia sp inactivation were 16 kV, 60 s, 2.5 L/min, respectively. The concentrations of total residual oxidants and ozone generated by plasma reaction increased with an increase of in voltage and reaction time, and the concentration of generated air did not increase above a certain amount.

• 한국환경과학회지
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• 제33권5호
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• pp.323-332
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• 2024

Circulating hydroponic cultivation has the advantage of reducing soil and water pollution problems caused by discharge of fertilizer components because the nutrient solution is reused. However, cyclic hydroponic cultivation has a low biological buffering capacity and can cause outbreaks of infectious root pathogens. Therefore, it is necessary to develop technologies or disinfection systems to control them. This study used dielectric barrier discharge plasma, which generates various persistent oxidants, to treat Fusarium oxysporum f. sp., a pathogen that causes wilt disease. Batch and intermittent continuous inactivation experiments were conducted, and the results showed that the total residual oxidant was persistent in intermittent plasma treatment at intervals of 2-3 days, and F. oxysporum was treated efficiently. Intermittent plasma treatment did not inhibit the growth of tomatoes.