• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.273-275
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• 2004

Recently, many water treatment facilities are operated by automatic control or by remote control. These high technology control systems require more stable power supply than before Badly most automatic control systems adopted in water treatment facilities are non-linear load which generates electrical harmonics inevitably. This study is intended to measure and analyze the electrical harmonics occurred at the chemicals control device which is inverter application circuit. and to show the effect of the harmonics filter.

• 대한조선학회논문집
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• 제40권5호
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• pp.10-16
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• 2003

To investigate the jet effect on circulation control, a segment of model was prepared and inserted horizontally across the test section of the cavitation tunnel. The hydrodynamic forces acting on the model were measured under the 2 dimensional flow behavior. Circulation flow control requires higher flow rate of water jet than boundary layer control does. Jet injection is effective in increasing lift coefficient and the increments reach to 160% in a certain combination of parameters such as an angle of attack, jet flow rate and flap angle. The blown water jet not only reduces form drag but also thrust effect, which is sometimes greater than the form drag in specific conditions.

• 한국지열·수열에너지학회논문집
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• 제18권4호
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• pp.33-44
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• 2022

In this study, we analyze the existing heating and cooling operation method for an office-type complex building with a central heating and cooling system, and examine the effects of applying various EMS that can be applied according to the load size to save energy in the building. For this purpose, simulation analysis was performed. As a control method, reset control of chilled water, hot water, cooling water and supply air temperatures, optimal start/stop of heat source, and number of heat source control were applied according to the load size, and energy consumption was analyzed accordingly. In addition, when all of these control methods were applied, the overlapping energy saving effect was finally confirmed. As a result, it was possible to confirm the energy saving effect when EMS for reset control and heat source control were applied compared to the existing control method of the heating and cooling system, and the effect for the case of using all these control methods in combination was also confirmed.

• International journal of advanced smart convergence
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• 제4권1호
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• pp.104-113
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• 2015

This paper focuses on a temperature effects on a PV panel which has been installed in Thailand. The main objective is cleaning PV panels and reduce temperature of PV panel by water injects from waterway and experimental results of PV power what it is difference. This project is designed by PLC control system which water injects and control PV temperature, In addition, this project consists of hardware and software such as water pump, water injection and PLC control has been automatically and it can be control system manually. The automatic control system is working when PV temperature rises up over 45 degree Celsius after that the pumping machine would inject water to the surface of PV panels and it must be stop when the PV panel temperature comes down less than 45 degree Celsius. The result of actual experimental found that the control system has been done correctly under specify condition. The experimental has been shown electrical data before and after water injects on PV system found that the electrical power a bit increases and The energy has been taken from PV panel less than energy consumption equipment of control system which taken to operate the water injecting system.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.453-458
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• 2008

Pump of high lift use to development of a technological level according as a building grow big. Water-Hammer to increase by valve of fast to closing agreeably to pipe laying to accept electronic valve, because by a damage of piping-system and the devil knows injury of vibration. Water-Hammer take a low effect to various method for solve. A New type manufacture develop and testing of pipe line to same to axis use to accumulator for water-Hammer to low effect and liner control of pressure. Impact-pressure of absorption ability and confirmation to decrease of vibration level through to preexistence manufactures and comparative test. Water-hammer and pipe vibration make low of piping system.

• 한국물환경학회지
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• 제22권6호
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• pp.1060-1067
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• 2006

Water quality in the Daecheong reservoir has been deteriorated by algal bloom due to nutrient supply from the upstream of the Daecheong reservoir after heavy rainfall. Algal bloom is propagated from eutrophicated tributary into the main body of the reservoir according to the hydrological conditions. This study is aimed to estimate the water current and temperature effect by the simulation of dam spill flow control using water quality model, CE-QUAL-W2 in 2003. Water current was resulted in nutrient transport from upstream of main reservoir and nutrients were delivered up to downstream by fast water velocity. Algal blooms occurred in stagnate zone of reservoir downstream as the current of downstream was retarded according to dam outflow control. Consequently water balance in stagnate zone triggered a rise of water temperature in summer. It affected algal bloom in the embayment of the reservoir. The simulation result by outflow control scenarios showed that spill flow augmentation induced in water body instability of stagnate zone so that water temperature declined. It could be suggested that outflow control minimize algal bloom in the downstream in the flooding season as long as water elevation level is maintained properly.

• 한국환경보건학회지
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• 제35권5호
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• pp.417-425
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• 2009

The purpose of this study was to investigate the whitening effect of Angelicae dahuricae Radix water extract (ADWE) by its application on artificial tanning spots which were induced by 1,500 $mJ/cm^2$ of UVB radiation on the backs of brown guinea pigs weighing approximately 450~500 g. Thirty ${\mu}l$ of ADWE, at each application, were applied twice a day, 5 days a week, for 8 weeks to the guinea pigs. The artificial tanning spots were divided into 3 groups which were vehicle control group [propylene glycol: ethanol: water (5:3:2)], positive control group (2% hydroquinone) and experimental group (2% ADWE). The visible whitening effect and changes in melanin index were evaluated once a week. On completion of the experiment, the animals were sacrificed under anesthetization, and the artificial tanning spots were excised by biopsy punch and stained with Hematoxylin and Eosin (H&E) to observe histological change and also stained with Fontana-Masson's silver (F-M) and S-100 to observe melanin pigmentation and melanocytes. In the gross observation, the experimental group showed higher pigmentation than the positive control group but lower pigmentation than the vehicle control group. Histological observation confirmed that ADWE had a positive whitening effect by showing a lower distribution of melanin and melanocytes in the epidermis of experimental group than in the vehicle control group.

• 신재생에너지
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• 제4권2호
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• pp.31-38
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• 2008

Using a surplus head in presented water supply pipes, we have studied to improve the operating efficiency of small hydro generator, which was chosen for a test model with 00 hydro power plant. With regard to power control and countermeasure of water hammer impact, Finally we have represented the optimal control method through the synthetical analysis of existing system symptoms, operation efficiency, the effect of water hammer impact and system configuration.

• 한국식품조리과학회지
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• 제16권6호
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• pp.623-628
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• 2000

The antioxidative effect of mugwort extracts was measured by DPPH and LDL with four different solutions (70% acetone, ethanol, hot water, cold water). Mugwort extracts contained 3.2% of polyphenol, 380 RE/l00 g of vitamin A, 16.2 mg/100 g of vitamin C, and 5.1 ${\alpha}$-TE/100 g of vitamin E. DPPH revealed the effect in the order of 70% acetone, hot water, ethanol, and cold water. In particular, 70% acetone showed outstandingly stronger activity than the control group. Also, when 10 ${\mu}\ell$ was added, the effect was well noticed. But the antioxidative activity was hardly seen at 15 ${\mu}\ell$. LDL exhibited the same order of strength in proportion to mugwort＇s concentration. Against the control group, the activity of 70% acetone was 7 times, hot water and ethanol 6 times, and cold water 2 times. This result is attributable to the antioxidative increase of polyphenol and antioxidative vitamins.

• 상하수도학회지
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• 제9권3호
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• pp.78-87
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• 1995

A study on the fouling control by periodical ozone-scrubbing was conducted in a membrane filtration process for drinking water treatment. Hydrophilic hollow fiber polyethylene membrane with pore size of $0.1{\mu}m$ and its surface area of $0.42m^2$ was used. Dead-End filtration method was selected to obtain high efficiency of energy. Laboratory prepared synthetic raw water with kaolin was used and the membranes were scrubbed by ozone once in an hour and once in two hours. When the duration of ozone scrubbing was increased from 10 seconds to 20 seconds, the rate of membrane fouling was significantly decreased. Although the frequency of ozone-scrubbing was reduced from once in an hour to once in two hours. the effect of fouling control was unchanged. However, ozone-scrubbing was not effective after a membrane was fouled and washed with detergent for reuse. Among several possible working effects of ozone, bactericidal effect was confirmed to be the primary reason of fouling control.