• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2003.05b
• /
• pp.399-400
• /
• 2003

싸이클론은 대기오염물질의 샘플링과 여러 산업공정에서 분진을 제어, 분리하는데 널리 사용되고 있다. 이는 싸이클론의 구조 및 형태가 간단하여, 제작과 운전이 쉽고 비용이 적게 들기 때문이다 하지만 작은 입자에 대한 분리효율이 낮기 때문에 싸이클론의 구조 및 형태를 변화시키거나 싸이클론내에 운전 조건을 변화시켜 높은 분리효율을 얻으려는 연구가 수행되어 왔다. 특히, 싸이클론내에 이중으로 원심력이 작용하게 한 double cyclone(Zhu et al., 2001)과 입자 하전 및 전기장 형성을 위해 고전압을 인가하는 전기싸이클론이(Lim et al., 2001) 최근에 연구가 되어지고 있다. (중략)

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.05b
• /
• pp.192-194
• /
• 2004

FFF에서 외부장은 시료의 종류에 따라 선택적으로 사용되며, 그 외부장의 종류에 따라 세부기술로 구분되어진다. 원심력(gravitational or centrifugal field)을 외부장으로 사용하는 침강장-흐름분획법(sedimentation FFF)은 지름이 0,05∼1um정도인 콜로이드 입자의 분리에 좋은 방법이다. 온도구배(thermal fradient)를 이용하는 열장-흐름분획법(thermal FFF)은 유기 고분자의 분리 및 고분자의 물성연구에 이용된다.(중략)

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.19 no.3
• /
• pp.10-15
• /
• 2011

The separation actuator for the small satellite should fix satellite appendages with high clamping force. After operation, it has to be separated from the satellite body without any damage on satellite system and release the appendages such as a solar panel and an antenna successfully. Therefore, we invent a non-explosive separation actuator for the small satellite which generates low shock and is resettable. In order to confirm performance of the proposed separation actuator, we carried out experiments for separation time, maximum preload for activation, and shock level.

• Korean Journal of Agricultural Science
• /
• v.16 no.1
• /
• pp.36-43
• /
• 1989

Out of 826 isolates of Streptomyces isolated from different soils, their distribution and antibiotic productivity were investigated. Distribution of the organism in the soil was affected by the soil conditions and plants. The highest isolation frequency was occurred from Quercus forest, Robinia forest and grass field, while soils from orchards and cultivating fields showed low density of Streptomyces. More than 49% of the isolates showed antibacterial activity against Bacillus subtilis, Erwinia carotovora subsp. carotovora and Xantomonas campestris pv. oryzae and about 40% of the isolates showed antiyeasty activity against Saccharomyces cerevisiae but only a few isolates showed antibiotic activity against E. coli and Pseudomonas solanacearum. Forty isolates of the Streptomyces showed strong antifungal activity against Pyricularia oryzae. Rate of isolation of Streptomyces was the highest on starch agar among the eight media tested. Antibiotic productivity of the isolates was the highest on potato sucrose agar medium among the 5 media tested.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.03b
• /
• pp.21-21
• /
• 2010

현재 시대에는 자원의 부족으로 인하여 원재료의 낮은 등급을 정제하는 것이 중요하다. 자기분리 기술이 산업 계 원재료들의 정제에 적용되는 것이 기대된다. 예를 들면 고순도의 유리나 절연체를 제작하기 위한 원재료에서 철산화물의 제거는 매우 중요하다. 자기를 띠는 입자들과 자기분리 필터 와이어 사이에 발생하는 끌어당기는 힘은 다른 자기분리와 비교 할 때 초전도 자기분리에서 훨씬 강하다. 초전도 마그네트를 이용하여 높은 자기장을 형성하기 때문에 일반 자기분리의 자성 입자 포획력을 능가한다. 본 연구에서는 습식 조건에서 산업계 원재료로부터 철계 산화물을 제거하기 위해서 초전도 자기문리를 사용하여 실험하였다. 실험에 사용된 시료는 유리원료로 사용되는 2종류로 시료A는 0.1 ~ 0.3 mm의 평균입도를 갖는 모래형상이며 시료B는 평균입도 0.03 ~ 0.1 mm의 고운모래 형태이다. 자기분리를 위해 상온에서 100 mm의 직경을 갖는 600 mm의 높이의 전도냉각형 Nb-Ti 초전도 마그네트를 사용하였으며 시료를 위에서 공급하고 아래로 배출되도록 수직형으로 설치하였다. 시료 500 g과 증류수 2 L를 혼합하여 교반시키고 6 T의 자기장 하에서 실험하였다. 자기분리 필터는 초전도 마그네트에서의 자기장의 분포를 해석하여 디자인하였다. 자기분리 필터의 자기적 특성을 알아보기 위해 진동시료형 자력계를 사용하였다. 산업계 원재료는 X선 형광분석기를 사용하여 성분을 분석하였다. 산업계 원재료를 이용하여 초전도 자기분리를 실시한 결과 철계 산화물은 시료A에서 43.5 %제거되었으며 시료B에서는 77.3%제거되었다.

• The Korean Journal of Mycology
• /
• v.18 no.2
• /
• pp.96-101
• /
• 1990

This study was conducted to select the promising antifungal microoganisms for biological control of wet bubble, Mycogone perniciosa. Ninty one isolates of fungi, 342 isolates of bacteria, and 556 actinomycetes were isolated from mushroom composts and soils, were subjected to primary screening test on agar medium base for their antimicrobial spectra. Among them, 12 bacteria and 71 actinomycetes were selected. Among the antibiotic producing microoganisms, 5 cultures were selected on the basis their antibiotic activities on casing soil with Benlate nontolerence M. perniciosa. Finally, AJ-117, AJ-136 and AK-139 were selected as microoganism with antifungal activity against two strains of M. perniciosa.

• Geotechnical Engineering
• /
• v.14 no.5
• /
• pp.111-128
• /
• 1998

An experimental study, which included four 305mm-diameter test shafts, one reference shaft with standard design and three test shafts with isolation tubes, is described. The soil was also soil heave and shrinkage that occur during suction changes at the field site. The test shafts were monitored for a period of about 18 months. Maximum ground movements exceeding 35mm were observed. Movements of only 1 to 2mm were observed in the test shafts with isolation tubes, while movements of 4 to 5mm were observed in the reference shaft. A simple computing model was developed to predict, based on suction changes, the maximum amount of ground heave. Relationship among suction. total stress, and volumetric strain was abtained in the laborstory. This relationship, used as inputs to the predictive model, enabled the computation of the maximum ground heave.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.28 no.4
• /
• pp.822-829
• /
• 1999

Antimicrobial activity of dandelion(Taraxacum platycarpum D.) was investigated. Methanol extract of dried dandelion was fractionated to hexane, chloroform, ethylacetate, butanol and aqueous fraction. Ethylacetate fraction among these fractions showed the highest inhibitory effect on the microorganisms such as B. subtilis, L. monocytogenes, S. aureus, E. coli and V. parahaemolyticus at $500\mu\textrm{g}/disc$. Ethylacetate fraction was further fractionated into 13 fractions by silica gel column and thin layer chromatography(TLC). The results showed that ethylacetate fractions No. 4, 5 and 6 had high antimicrobial activity. These were mixed again, re separated and five fractions were obtained. Among them, No. 2 fraction had the highest inhibitory effect on the microorganisms, which was then separated into six fractions. In the 3rd fractionation, No. 3 fraction was identified as benzoic acid by HPLC, $^{1}H-NMR$ and GC MS.

• Membrane Journal
• /
• v.30 no.2
• /
• pp.124-130
• /
• 2020

Climate change is getting worse in the 21st century. So, water shortages are expanding worldwide. Carbon dioxide generated from the use of fossil fuels is 80% of the total green house gas. Because it occupies, it has become a factor of global warming. Therefore, the importance of water treatment membrane, gas separation membrane, and secondary battery separation membrane is increasing, but it occupies technology in developed countries such as the United States, Japan, and Germany. Therefore, the advancement of membrane technology is urgently required. So, although the country supports a lot of research budgets, We will analyze the results using NTIS data. As a result of the analysis used, it is supported mainly for short-term tasks, and the research budget is small compared to other technical fields, so the basic material field technology is weak. Therefore, when we invest a lot of long-term tasks, with a lot of budget, and universities, membrane technology has been improved and competitiveness has been strengthened.

• Korean Journal of Organic Agriculture
• /
• v.7 no.2
• /
• pp.99-106
• /
• 1999

In order to acquire microbial agents that can be utilized for biological control of bitter rot(Glomerella cingulata), the major airborne disease to apple, the effective microorganisms were isolated, tested for antagonistic activity to the pathogen. Through the screening of more than 1,000 species of microorganisms collected in nature, 11 species of antagonists were selected. On of the 11 species, one species designated as CH141 demonstrated outstanding activity. The bacterial strain, CH1141 exerted antagonistic efficiency of 65% on Glomerella cingulata. The CH1141 was identified as a bacterial strain to Bacillus subtilis based on morphology, culture conditions, and physiobiochemical characteristics.