• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.02a
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• pp.145-150
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• 2003

최근 육묘 시설의 양적 증가와 육묘 기술 수준의 향상에 힘입어 플러그 묘의 보급이 확대되고 있다. 더구나 육묘와 재배의 분업화가 진행되고, 고품질 묘의 안정된 수급에 대한 관심이 늘어나면서 육묘 산업에 대한 비중이 점차 증가하고 있다. 현재 국내에 설치되어 있는 온실, 터널 등의 모든 육묘 시설은 개방형 묘생산 시스템으로 자연광을 이용한 장점을 지니고 있으나, 여름철의 냉방과 겨울철의 난방에 소요되는 비용은 상당한 수준에 이르고 있다. 더구나 외부 기상조건과 밀접한 관계를 이루며 변화하는 특성을 가지고 있어 효율적인 환경제어를 위하여 차광과 보온 등의 시설이 필요하며(이 등, 1995), 관리노력이 적지 않게 요구되고 있다. (중략)

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2007.05a
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• pp.149-153
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• 2007

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.07a
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• pp.402-406
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• 2003

묘생산 시스템은 크게 개방형과 폐쇄형으로 구분된다. 개방형 묘생산 시스템은 시스템 내부와 외부의 공기ㆍ물ㆍ열 등의 교환이 가능한 시스템을 의미한다. 현재 실생묘, 삽목묘, 접목묘 등은 일사가 투과되는 온실 또는 묘포장에서 생산된다. 그러므로 온실 또는 묘포장을 이용한 묘생산 시스템은 개방형 묘생산 시스템에 해당한다. 개방형 묘생산 시스템에서는 외부기상의 변동에 따라 시스템 내의 기온, 상대습도, 광량, 기류속도, $CO_2$ 농도 등의 물리적 환경요인이 변화하므로 이들 환경 요인을 일정한 수준으로 제어하기가 쉽지 않다. 때문에 균일한 묘소질을 지닌 묘의 계획적 생산이 근본적으로 불가능하다. (중략)

• Proceedings of the Membrane Society of Korea Conference
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• 1994.04a
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• pp.38-38
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• 1994

일반적으로 다공성 비대칭막은 상분리법에 의하여 제조하는데, 분리막을 구성하는 고분자를 적절한 용매에 녹인 제막용액을 일정한 두께로 casting하고 이를 비용매에 담가서 binodal/spinodal decomposition이 일어나도록 하여 제조한다. 이 방법으로 제조된 다공성 분리막의 성능은 표면층에 존재하는 pore의 크기와 그 분포 및 porosity에 의해 결정된다. 표면층의 pore size와 분포를 조절하기 위하여 그간 고분자 용액내의 고분자 농도조절, 첨가제의 사용, 비용매의 조성을 바꾸는 등의 여러가지 방법에 대한 연구가 진행되어 왔다. Casting된 고분자 용액을 비용매에 침잠시켜 다공성막을 형성시킬 경우 막의 표면과 비용매 사이의 계면에서 용매와 비용매의 교환이 일어난다. 용매-비용매 교환이 일어나면 제막된 고분자 용액이 열역학적으로 불안정해져 상분리가 일어난다. 이 때 용매-비용매의 교환이 매우 빠른 속도로 일어나 pore-size의 분포를 조절하기가 매우 어렵다.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.2
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• pp.95-103
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• 2018

As a guideline for desulfurization and dehumidification pretreatment facility for optimizing utilization of biogas, the $H_2S$ concentration is set at 150 % which can be treated with iron salts, dehumidification is the optimum value for generator operation, and the relative humidity applied at the utilization of biogas in EU is set at 60 %. We have set up the generator facility guidelines to optimize utilization of biogas. The appropriate amount of biogas should be at least 90 % of the total gas generation, and the capacity of generator facility should be set at 20~30 %. In order to equalize the pressure of the incoming gas the generator, a gas equalization tank should be installed and the generator room average temperature should be kept at $45^{\circ}C$ or less. Since the gas is not produced at a certain methane concentration in the digester, the efficiency is lowered. Therefore, it is required to install an air fuel ratio control system according to the change in methane concentration. Therefore, it is necessary to compensate for the disadvantages of biogasification facilities of organic waste resources and optimize utilization of biogas and improve operation of facilities. This study was conducted to optimize biogas utilization of type of organic waste(containing sewage sludge and food waste, animal manure), investigate the facilities problem and propose design, operation guidelines such as pre-treatment facilities and generators.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.3
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• pp.191-200
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• 2016

The ventilation effect of a ventilation system, which is classified as the forced ventilation and natural ventilation, is predominantly dependent on the combination of air supply and discharge. Perhaps the simplest ventilation is merely supplying the air as it is. However, to improve the indoor working environment during the summer, an air supply that is cooled to some extent has been widely adopted. Recently, a cooling method utilizing the vaporization of water was introduced. In this study, the performance of an evaporation-type air supply unit that was produced by Japan K-company and was installed in a shoe-manufacturing plant in Busan was investigated. The purpose of the experiment was to measure how much the supplied air could be cooled. From this experimental study, we confirmed that the evaporation-type air supply system is efficient, capable of improving the working environment during the summer while minimizing the energy cost.

• Journal of Conservation Science
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• v.36 no.5
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• pp.368-382
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• 2020

It was confirmed that a white porcelain figurine in underglaze iron was damaged after exhibition. This study analyzes the current state of salt damage on the artifact and identifies the factors contributing to its deterioration by examining the material characteristics of the artifact and exhibition environment. The analysis will thus assist in preparing a conservation scheme for artifacts. The crystallized carbonate on the surface of the white porcelain figurine is a water-soluble alkali salt with high hygroscopicity and high solubility in water. This solubility increases as the temperature increases. The figurine was low-fired at approximately 1000℃. A lead glaze was applied, and thin cracks were formed on the glazed surface, indicating poor surface properties. Our analysis suggested that the showcase used in the exhibition likely created a moist environment resulting from condensation, as it was exposed to high temperature and relative humidity, particularly in comparison to the exhibition room where the temperature was regulated using an air conditioner. In addition, the artifacts in the showcase were exposed to sudden changes in temperature and relative humidity as the air conditioner was repeatedly turned on and off. Therefore, it can be deduced that the soluble salt remaining on the white porcelain figurine moved toward the surface of the relatively weak glaze as a result of the temperature, and the crystallized salt exacerbated surface damage as the moisture evaporated in a dry environment.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.409-414
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• 2010

The first drainage time in a day was controlled for precise irrigation management with low consumption of nutrient solution in tomato perlite bag culture system by measuring water level of drained water in drainage catchment part. This method automatically adjusted the irrigation time under any condition of light, temperature and humidity, resulting in stable water content in substrates. However, it was difficult to keep the time consistent as they were set. It drained with the deviation of 20 min in the treatment in which the first drainage time was set at 10:00 and 50 min in the treatment set at 10:30. The first drainage time was not constant, but the drain occurred stably before noon in the treatment of which irrigation frequency was longer than 30 min. The drainage ratio was better balanced in all the treatments using drainage level sensors than the treatment using time clock for irrigation control. High water and fertilizer efficiencies were obtained. Although the growth, total yield and sugar content were not significantly different between the treatments, fruit weight was higher in the treatments using drainage level sensors than that using timer.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.681-686
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• 2009

Cronobacter spp. (Enterobacter sakazakii) is known to be highly resistant to dry conditions than any other Enterobacteriaeae. In this study, one hundred and ten Korean Cronobacter isolates were characterized to find out their survival characteristics under conditions of desiccation and humidity. Thirty percentage strains of the isolates showed high resistance to desiccation exposed on the metal surface for eight hours by half survival of the initial number, whileas less than 10% strains showed dry sensitivity by less one log scale survival among seven log scales. Finally, more than 90% of the strains consisted of dry-resistant and dry-intermediate groups. The same tendencies were evident in a 15-day exposure. Dry-resistant and intermediate strain groups showed 3 log scale survival among 5 log initial numbers in the powdered infant formula for 30 days, which were more resistant than on the above metal surface exposed. So, almost the isolate strains showed high resistance to dry condition. Dry-resistant and intermediate groups exposed on the metal surface formed a biofilm at the beginning, and the dry-sensitive group showed biofilm formation mainly only after a 7-day exposure. However, without a time difference in formation of biofilm, the dry-resistant and sensitive isolates seemed to similar biofilm formation activity. Most of the isolates showed very low survival at 75% relative humidity in 48 hours; however, they showed high resistance by 60% survival at 40% relative humidity. The Cronobacter isolates showed high resistance to desiccation on the metal surface and in the powdered infant formula, but low survival at high relative humidity. Therefore, high humidity may be a control method for Cronobacter in food processing environments.

• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.114-119
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• 2012

We have conducted 4 experiments to develop the most environmental and effective use of the two-fluid fog system to prevent and exterminate whiteflies in tomato cultivation. In particular, these experiments used Vitamini tomatoes grown in stand-alone greenhouses at Buyeo Tomato Experiment Station as subjects. Each experiment utilized the fog system in a different way. The first experiment provided the control group, which was subject to the two-fluid fog system without additional humidity control. In the second experiment, the two-fluid fog system controlled the humidity level to be above 70%. The third and the fourth experiment utilized natural substances, which were 1.5 mg/L of Neem Oil and 2 mg/L of Oleic acid respectively, without additional humidity control. From the first experiment, we could observe that a simple use of the two-fluid fog system decreased the density of whiteflies in the greenhouses. This impact of the fog system on whiteflies was greater in the second experiment. By comparing the first and the second experiment, we concluded that whiteflies are more effectively prevented by maintaining a higher humidity level via the fog system's smaller water droplets that float in the air for longer time than the standard fog system in rather dry condition. In the third and the fourth experiments, the extermination level was 78% and 76.4% respectively, comparing only 53% in the first experiment without the humidity control. Therefore, using the natural substances in addition to the humidity control increases the extermination effectiveness. Considering the similar results from the 3rd and the 4th experiments, Oleic acid has a greater appeal for its lower price. Using the two-fluid fog system to both control the humidity on a daily basis and spray the substances for occasional extermination would reduce labor cost and increase production in an environmental way.