• Asian-Australasian Journal of Animal Sciences
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• 제3권2호
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• pp.143-148
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• 1990

An experiment was conducted to compare the traditional weigh-suckle-weigh method and the $D_2O$ dilution technique to estimate milk consumption of suckling piglets. Milk consumption of 50 individual piglets was estimated on four consecutive days by the $D_2O$ dilution method and for approximately 8 hours on both the second and fourth day by the traditional WSW method. The average milk intake of piglets estimated by the $D_2O$ dilution method was 45.0 g/hr and there were no significant differences between the four measurement period. The traditional weigh-suckle-weigh method provided a significantly lower estimate of milk consumption (36.8 g/hr). However correction for weight losses associated with milk suckling and weighing would increase the weigh-suckle-weigh estimate to a level similar to that determined by the $D_2O$ dilution method.

• 한국수산과학회지
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• 제32권1호
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• pp.56-61
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• 1999

참메기, Silurus asotus를 대상으로 수온 ($15^{\circ}C,\;20^{\circ}C,\;25^{\circ}C$ 및 $30^{\circ}C$)과 광주기 (24L:0D, 12L:12D 및 0L:24D)에 따른 산소 소비량의 변화를 연속적인 컴퓨터 모니터링 시스템을 이용하여 조사하였다. 평균 무게 280g의 참메기의 산소 소비량은 수온의 증가에 따라 증가하였고, $15^{\circ}C$에서 $35.2\~96.4mg\;O_2/kg$ fish/hr, $20^{\circ}C$에서$78.6\~127.9mg\;O_2/kg$ fish/hr, $25^{\circ}C$에서$120.1\~231.7mg\;O_2/kg$ fish/hr, $30^{\circ}C$에서 $197.5\~352.3mg\;O_2/kg$ fish/hr으로 나타났다(p<0.05). 광주기에 따른 산소 소비량은 암기 조건에서 보다 명기 조건에서 산소소비량이 더 높게 나타났다. 또한, 24L:0D와 12L:12D와 비교하여 0L:24D에서 평균 산소 소비량이 낮게 나타났다(p<0.05). 산소 소비량의 최대값과 최소값의 차이는 수온이 상승함에 따라 증가하였고, 12L:12D에서 가장 큰 것으로 나타났고, 새벽녁과 저녁 무렵에 산소 소비량의 급격한 변화를 나타내었다. 특히, 12L:12D의 조건에 두었을 때 명기와 암기에 대한 뚜렷한 반응을 보였다.

• Journal of Electrochemical Science and Technology
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• 제12권2호
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• pp.266-271
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• 2021

A commercial PbO₂ electrode was adopted as the anode for the electrochemical degradation of the real textile effluent with the initial COD of 56.0 mg L^-1 and the stainless steel plate as the cathode. The effect of the initial pH, the electrolyte flow rate and the cell voltage on the COD, the current efficiency and the energy consumption were investigated without the addition of NaCl or Na₂SO₄. The experimental results illustrated that the PbO₂ electrode can reduce the COD of the textile effluent from 56.0 mg L^-1 to 26.0 mg L^-1 with the current efficiency of 86.1% and the energy consumption of 17.5 kWh kg^-1 (per kilogram of degraded COD) under the optimal operating conditions. Therefore PbO₂ electrode as the anode was promising to further electrochemically degrade the real textile effluent.

• Journal of Electrochemical Science and Technology
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• 제10권2호
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• pp.115-122
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• 2019

In order to improve the current efficiency and reduce the energy consumption in the electrosynthesis of ammonium persulfate, electrolytic properties of a perfluorosulfonic cation exchange membrane named PGN membrane and the $Al_2O_3$ ceramic membrane in the electrosynthesis of ammonium persulfate were studied and compared in a pilot electrolytic cell using a welded platinum titanium as the anode and a Pb-Sb alloy as the cathode. The effect of cell voltage, electrolyte flow rate and electrolysis time of the electrolytes on the current efficiency and the energy consumption were studied. The results indicated that the PGN membrane could improve current efficiency to 95.12% and reduce energy consumption to $1110kWh\;t^{-1}$ (energy consumption per ton of the ammonium persulfate generated) under the optimal operating conditions and the highest current efficiency of the $Al_2O_3$ ceramic membrane was 72.61% with its lowest energy consumption of $1779kWh\;t^{-1}$. Among 5 times of the electrolysis of the electrolytes, the lowest current efficiency of the PGN membrane was 85.25% with the highest energy consumption of $1244kWh\;t^{-1}$ while the lowest current efficiency of the $Al_2O_3$ ceramic membrane was 67.44% with the highest energy consumption of $1915kWh\;t^{-1}$, which suggested the PGN membrane could be used in the 5-stage electrolytic cell for the industrially continuous electrosynthesis of ammonium persulfate. Therefore the PGN membrane can be efficient to improve the current efficiency and reduce the energy consumption and can be applied in the industrial electrosynthesis of ammonium persulfate.

• 한국양식학회지
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• 제12권3호
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• pp.247-254
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• 1999

Changes of oxygen consumption of Nile tilapia in relation to different body sizes(average body weight 4 g, 40 g, 120 g and 400 g) and water temperatures ($20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$) were investigated by a continuous oxygen monitoring system. Mean oxygen consumption of 4 g, 40 g, 120 g and 400 g Nile tilapia at $20^{\circ}C$ were 318.8, 214.9, 84.1 and 69.4 mg $O_2$/kg fish/hr and that at $25^{\circ}C$ were 435.2, 345.9, 151.5 and 115.9 mg $O_2$/kg fish/hr, and that at $30^{\circ}C$ were 611.1, 538.4, 320.8, and 236.0 mg $O_2$/kg fish/hr, respectively. Oxygen consumption per unit body weight tended to decrease exponentially at all temperatures (P<0.05) as body weigth of the fish increased. Oxygen consumption of this fish at $25^{\circ}C$ was $1.61\pm0.18$ times higher than that at $20^{\circ}C$ and oxygen consumption at $30^{\circ}C$ was $1.53\pm0.27$ times higher than that at $25^{\circ}C$. Oxygen consumption per unit body weight linearly increased with the water temperature increased. Also, oxygen consumption of this fish during day time was higher than that during night time at 12L:12D day light condition. The differences between maximum and minimum daily oxygen consumption of this fish increased with the water temperature increased.

• 한국수산과학회지
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• 제32권2호
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• pp.144-148
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• 1999

상업적 규모의 순환여과식 탱크에서 사료 공급 횟수에 따른 산소 소비량의 변화를 조사하였다. 실험에 이용된 사육 장치는 순환여과식 시설내의 원형 콘크리트 탱크 (직경 270cm, 높이 80cm)를 이용하여 평균 체중 400g의 나일틸라피아 (Oreochromis niloticus)를 390kg 방양하여 실험에 이용하였다. 우선 3일간 사육 어류를 절식시킨 후 기초대사율을 측정하였고, 사료 공급 횟수를 1회, 2회, 5회 그리고 9회로 나누어 공급한 후 산소 소비량의 일간 변화를 측정하였다. 절식 상태에서 산소 소비량 (기초대사율)은 평균 $39.31{\pm}4.4mg\;O_2/kg$ fish/hr이였고 사료 공급횟수에 따른 1일 평균 산소 소비량은 1회, 2회, 5회 및 9회 공급시 각각 $79.9{\pm}21.5,\;81.3{\pm}14.8,\;84.2{\pm}9.9$ 및 $98.9{\pm}11.0mg\;O_2/kg$ fish/hr을 소비하는 것으로 나타나 사료 공급 횟수가 증가함에 따라 평균 산소 소비량은 증가하였으나, 유의적인 차이는 나타나지 않았다. 사료 공급후 최대 산소 소비량에 도달하는 시간은 사료 공급후 30$\~$50분으로 나타나 사료공급 횟수와는 유의적인 상관 관계가 없는 것으로 나타났다. 사료공급 횟수에 따른 산소 소비량의 최대치는 1회, 2회, 5회 및 9회 공급시에 각각 161.2, 123.4, 111.1 및 111.1 mg $O_2/kg$ fish/hr을 소비하는 것으로 나타나 하루에 1회 공급하였을 때 최대 산소 소비량이 가장 높은 것으로 나타났다.

• 대한기계학회논문집B
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• 제27권7호
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• pp.893-900
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• 2003

Numerical simulations of freely propagating flames burning stoichiometric C $H_4$/CHC1$_3$/ $O_2$/$N_2$ mixtures are performed at atmospheric pressure in order to understand the effect of the $O_2$ enrichment level and the CHC1$_3$/C $H_4$ molar ratio. A chemical kinetic mechanism is developed, which involves 69 gas-phase species and 379 forward and 364 backward reactions. The calculated flame speeds are compared with the experiments for the flames established at several CHC1$_3$/C $H_4$ molar ratio (R<1), the results of which is in excellent agreement. As a results of the increased $O_2$ enrichment level from 0.21 to 1, the flame speed and the temperature in the burned gas are increased. At high CHC1$_3$/C $H_4$ molar ratio two peak values appear on the $O_2$ consumption rate, which are affected by CC1$_2$＋ $O_2$$_{-}$>C1O+CC1O and H＋ $O_2$$_{-}$>O＋OH.＋OH.

• 한국패류학회지
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• 제24권3호
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• pp.261-267
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• 2008

수온 및 염분에 따른 굴의 일반적인 대사경향을 알아보기 위하여 수온과 개체크기에 따른 산소소비율과 암모니아 질소 배설률을 측정하였으며, O:N원자비를 산출하였다. 산소소비율과 암모니아 질소배설률은 개체의 크기가 작을수록 높았으며, 수온증가에 따라 증가하였다. O:N 원자비는 일반해수에서 8-40의 범위에 있었으며, 수온 $25^{\circ}C$에서 O:N 원자비는 8로 감소하였는데, 이는 산란기에 주요 대사기질로서 단백질을 이용하며, 단백질의 요구가 큰 것으로 추정된다. 이 결과는 굴양식장의 지속적인 관리 및 적정 수용력 산정을 위한 기초자료로 활용이 가능하다.

• 한국대기환경학회지
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• 제14권4호
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• pp.333-342
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• 1998

Plasma process has great possibilities to remove SOx, NOx simultaneously with high treatment efficiency and is expected to be suitable for small or middle plants. It was accomplished to evaluate SO2, NOx control possibility and achieve basic data to control pollutants by use of Surface Discharge Induced Plasma Chemical Process (SPCP) in this study. O3 generation characteristics by discharge of a plate was proportional to O2 concentration and power consumption and inversely proportional to temperature and humidity, In case of dry air, NOx was highly generated by N2 and O2 in air during the plasma discharge process but it was decreased considerably as H2O was added. SO2 removal efficiency was very high, and removal rate was 170,350 mEA at 30,50 watt respectively in flue gas which is usually contain HIO. NOx removal efficiency was about 57% at 40 watt power consumption with 7.5% humidity. It is estimated that H2O has an important role in reaction mechanism with pollutants according to plasma discharge.

• Environmental Engineering Research
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• 제24권3호
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• pp.389-396
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• 2019

The electrical energy consumption (EEC) in removal of NO by a $UV/H_2O_2$ oxidation process was introduced and related to removal efficiency of this gas. The absorption-reaction of NO was conducted in a bubble column reactor in the presence of $SO_2$. The variation in NO removal efficiency was investigated for various process parameters including NO and $SO_2$ inlet concentrations, initial concentration of $H_2O_2$ solution and gas flow rate. EEC values were obtained in these different conditions. The removal efficiency was increased from about 22% to 54.7% when $H_2O_2$ concentration increased from 0.1 to 1.5 M, while EEC decreased by about 70%. However, further increase in $H_2O_2$ concentration, from 1.5 to 2, had no significant effect on NO absorption and EEC. An increase in NO inlet concentration, from 200 to 500 ppm, decreased its removal efficiency by about 10%. However, EEC increased from $2.9{\times}10^{-2}$ to $3.9{\times}10^{-2}kWh/m^3$. Results also revealed that the presence of $SO_2$ had negative effect on NO removal percentage and EEC values. Some experiments were conducted to investigate the effect of $H_2O_2$ solution pH. The changing of pH of oxidation-absorption medium in the ranges between 3 to 10, had positive and negative effects on removal efficiency depending on pH value.