• 생명과학회지
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• 제10권5호
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• pp.504-510
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• 2000

This study was designed to investigate the effects of mulberry (Morus alba L.) leaf extract (MLE) on oxygen radicals and their scavenger enzymes in liver membranes of rats. Sprague-Dawley (SD) male rats (160$\pm$10 g) were fed basic diet (control group), and experimental diets (MLE-100 and MLE-300 groups) added 100 and 300 mg/kg BW/day for 6 weeks. Hydroxyl radical (.OH) levels resulted in a significant decreases (15.2% and 18.1%, 5.6% and 8.0%, respectively) in liver mitochondria and microsomes could be not obtained. These are no significant differences in superoxide radical ($O_2$) levels of liver cytosol in MLE-100 and MLE-300 groups compared with control group. Lipid peroxide (LPO) levels were slightly decreased about 13.6% and 6.1% in liver mitochondria and microsomes of MLE-300 group compared with control group. Oxidized protein (OP) levels were remarkably decreased about 16.9% and 27.2% in liver microsomes only of MLE-100 and MLE-300 group compared with control group. Mn-SOD activities in liver mitochondria were remarkably increased (18.2% and 28.7%, respectively) in MLE-100 and MLE-300 groups, and Cu,Zn-SOD activities in liver cytosol were also significantly increased (11.3% and 20.2%, respectively) in MLE-100 and MLE-300 groups compared with control group. Mn-SOD activities in liver mitochondria were remarkably increased (18.2% and 28.7%, respectively) in MLE-100 and MLE-300 groups, and Cu,Zn-SOD activities in liver cytosol were also significantly increased (11.3% and 20.2%, respectively) in MLE-100 and MLE-300 groups compared with control group, but significant difference between GSHPx activities in liver cytosol could be not obtained. These results suggest that anti-aging effect of mulberry leaf extract (MLE) may play a pivotal role in attenuating a various age-related changes.

• 전기학회논문지
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• 제67권11호
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• pp.1477-1485
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• 2018

There are two major issues for activated sludge process in sewage treatment plant. One is how to make sewage be more clean and the other is the energy saving in sewage treatment process. The major monitoring sewage qualities are chemical oxygen demand, phosphorus, nitrogen, suspended solid in effluent. These are transmitted to the national TMS(Telemetry Monitoring System) at every hour. If these exceed the environmental standard, the environmental charges imposed. So, these water qualities are to be controlled below the environmental standard in operation of sewage treatment plant. And recently, the energy saving is also important in process operation. Over 50% energy is consumed in blowers and motors for injection oxygen into aeration tank. So, with the water qualities to be controlled below the environmental standard, the energy saving also is to be accomplished for efficient plant management. Almost researches are aimed to control water quality without considering energy saving. AI techniques have been used for control water quality. AI modeling simulator provided the optimal control inputs(blower speed, waste sludge, return sludge) for control water quality. Blower speed is the main control input for activated sludge process. To make sewage be more clean, the excessive blower speed is supplied, but water quality is not better than the previous. In results, non necessary energy is consumed. In this paper we propose a new method that the energy saving also is to be accomplished with the water qualities to be controlled below the environmental standard for efficient plant management. Water qualities in only aeration tank are used the inputs of fuzzy models. Outputs of these models are chemical oxygen demand, phosphorus, nitrogen, suspended solid in effluent and have the environmental standards. In test, we found this method could save 10% energy than the previous methods.

• 한국수산과학회지
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• 제31권6호
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• pp.785-790
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• 1998

인체용 마취제인 염산리도카인을 사용하여 버들개, Rhynchocypris steindachneli의 운송실험을 실시하였다. 대조군. sham 대조군 및 염산리도카인 농도 2.5ppm군, 5ppm군, 10ppm군, 20ppm군을 대상으로 실험후 30분, 60분, 90분, 120분, 240분 및 360분에 용존산소, ventilation rate, ammonia성 질소 및 pH를 측정하였다. 실험후 시간 경과에 따라 고농도 염산리도카인군, sham 대조군, 대조군 순으로 용존산소량이 높았으며 ventilation rate도 용존산소량의 결과와 상응하였다. 염산리도카인군은 물질대사가 저하하였기에 물질대사물인 ammonia 배출이 대조군에 비해 낮았고, 염산리도카인군에서는 농도의존적으로 ammonia 농도가 낮아졌다. 실험후 시간경과에 따른 sham 대조군과 염산리도카인군의 pH 감소는 대조군의 pH 감소에 비해 그 감소 정도가 약하게 나타났다. 본 연구 결과 염산리도카인은 버들개의 운송실험시 진정제로 효과적이었다.

• 생명과학회지
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• 제10권4호
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• pp.354-361
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• 2000

The effect of mulberry (Morus alba L.) leaf extract(MLE) on oxidative stress and membrane fluidity in brain membranes of SD rats fed with 100 and 300 mg/kg BW/day were carried out for 6 weeks. Cholesterol accumulations resulted in a consistent decreases (4.6% and 5.6%, respectively) in brain mitochondria and microsomes of MLE-300 group compared with control group. Membrane fluidities were dose-dependently increased (2.2% and 5.1%, 5.0% and 15.2%) in brain mitochondria and microsomes of MLE-100 and MLE-300 groups compared with control group. Basal oxygen radicals(BORs) in brain mitochondria and microsomes were significantly inhibited (15.7% and 25.1%, 9.0% and 12.4%, respectively) by MLE-100 and MLE-300 groups compared with control group. Induced oxygen radicals(IORs) in brain mitochondria and microsomes were significantly inhibited (8.9% and 13.1%, 16.5% and 23.2%, respectively) by MLE-100 and MLE-300 groups compared with control group. Lipid peroxide (LPO) levels were significantly decreased (8.5% and 18.1%, 7.6% and 12.3%) in brain mitochondria and microsomes of MLE-100 and MLE-300 groups compared with control group. Oxidized protein (OP) levels were dose-dependently decreased (4.3% and 14.2%, 10.0% and 10.9%, respectively) in brain microsomes of MLE-100 and MLE-300 groups compared with control group. These results suggest that MLE may play an effective role in an attenuating an oxidative stress and increasing a membrane fluidity in brain membranes.

• KSBB Journal
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• 제23권4호
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• pp.317-322
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• 2008

본 연구를 통하여 자체 구동형 모터를 갖는 BOD 센서를 개발하였으며, 6,000초 이상 측정한 결과 안정적인 측정이 가능함을 확인하였다. 응답시간은 30초 이내, 재현성은 1 ppm 이내, 선형성은 99%의 우수한 성능을 갖는 BOD 센서를 개발하였다. 최대 산소소모속도 (Maximum Oxygen Uptake Rate, $OUR_{max}$)와 $BOD_5$ 상관관계는 $BOD_5$ (ppm)=-2,490+33,889 ($OUR_{max}$)로서, 95.6%의 우수한 선형성을 보였다. 자체구동형 BOD 센서를 이용하여 시료의 전처리부터 BOD의 측정까지 자동으로 제어 및 측정되는 시스템을 구성하였다. 본 연구를 통하여 최대 산소소모속도 ($OUR_{max}$)와 $BOD_5$ 상관관계를 구한 후 수분내에 $BOD_5$ 값을 예측할 수 있었다.

• KSBB Journal
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• 제16권5호
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• pp.516-522
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• 2001

균사형성 미생물에 의한 항생물질의 대량생산은 적절한 산소공급이 요구되며, 산소전달속도는 생산성에 영향을 미치는 속도제한단계이다. 그러므로 발효에 이용하기 위해 Streptomyces avermitilis 와 같은 균사형성 미생물 배양액에서의 산소전달계수를 측정하였다. 그러나 회분식 배양에서 (K$_{L}$A) 측정을 위한 적절한 용존산소 유지가 어려웠으며, 이를 극복하기 위해서 유가식 배양을 도입하였다. 배지의 단계적 공급으로 미생물 성장속도를 조절할 수 있었고, 낮은 교반속도에서도 적정용존산소의 유지가 가능하였으며, 결과적으로 (K$_{L}$A) 측정도 용이하였다. 7 g/L 이하의 낮은 균체량에서 350 rpm의 교반속도가 교반효율과 전단응력을 고려했을 때 가장 적절한 조건임을 알수 있었다. 그러나 균체가 증가할수록 배양액 점도가 증가하여 혼합이 효과적이지 못한 이유로 더 높은 교반속도가 필요하였다. 통기량의 증가에 의한 (K$_{L}$A) 증가율은 건조균제질량이 고 농도 일수록 미미하였다. 그러므로 높은 균체농도에서는 이차대사산물에 영향을 주지 않은 범위에서 교반속도를 증가하여 용존산소 농도를 조절하는 것이 통기속도의 조절보다 더 효율적 일 것으로 판단되었다.판단되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.306.2-306.2
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• 2016

Niobium oxide thin films were synthesized by reactive rf magnetron sputtering. The target was metallic niobium with 2 inch in diameter and the substrate was n-type Si wafer. To control the surface properties of the films, Nb oxide thin films were obtained at various mixing ratios of argon and oxygen gases. Nb oxide thin films were analyzed with alpha step, scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The result of alpha step showed that the thickness of Nb oxide thin films were decreased with increasing the oxygen gas ratios. SEM images showed that the granular morphology was formed at 0% of oxygen gas ratio and then disappeared at 20 and 75% of oxygen gas ratio. The amorphous Nb oxide was observed by XRD at all films. The oxidation state of Nb and O were studied with high resolution Ni 2p and O 1s XPS spectra. And the change in the chemical environment of Nb oxide thin films was investigated by XPS with Ar+ sputtering.

• 한국전기전자재료학회논문지
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• 제18권7호
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• pp.600-604
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• 2005

We studied that structural and optical properties of ZnO films depend on oxygen contents. ZnO films were deposited on Si (111) substrates at room temperature by rf sputtering system and the thickness of films was 100 nm. The ZnO films were annealed in thermal furnace for 2 h at 800 and $900^{\circ}C$ in $H_2O,\;N_2$, and air ambient gases to control oxygen contents. We used AES, PL, XRD, AFM. As our result, crystal quality and luminescence improved until O/Zn is 1. However, when O/Zn ratio Is larger than 1, the structural and optical properties were getting worse.

• 한국분무공학회지
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• 제19권4호
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• pp.211-215
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• 2014

The main purpose of this study is to provide basic information of droplet soot generation of decane fuel. To achieve this, this paper presents the experimental results on the decane droplet combustion conducted under various ambient pressure($P_{amb}$), and oxygen concentration($O_2$) conditions. At the same time, the experimental study was conducted in terms of soot volume fraction($f_v$) and its maximum value. Also, visualization of single fuel droplet was conducted by high resolution CCD camera and ambient pressure($P_{amb}$) and oxygen concentration($O_2$) was changed by control system. It was revealed that higher ambient pressure($P_{amb}$), and oxygen concentration($O_2$) enhanced the soot generation and improved the maximum soot volume fraction( $f_v$).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 추계학술대회 논문집
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• pp.101-105
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• 1994

A/F sensor with a sensing and a pumping element, which is made of YSZ(yttria stabilized zirconia) sheets, can be used for the combustion control of lean burn engine. A/F sensor can detect the oxygen partial pressure in more wide range than the other oxygen sensors, such as the limiting current type oxygen sensor and λ-sensor. However this sensor has the disadvantage that the characteristics has been degraded rapidly due to the physical or electrochemical reasons. The blackening phenomenon is known as one of the degradations caused by high voltage biased for oxygen pumping. In this paper, we have studied to analyze the blackening phenomenon by comparing two characteristics between before and after blackening in impedance spectroscopy, and discussed the blackening mechanism.