• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.949-954
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• 2012

This study is conducted to evaluate the effects of chelating agents for improving plant growth and reusing accumulated nutrients in soils of plastic film house. Two experiments were carried out at follows: i) The incubation test was conducted using soils treated with 0, 300 mM of EDTA and DTPA to examine the availability of nutrients. ii) For the pot test, chinese cabbages were cultivated in soils with 0, 0.1, 0.5, 1, and 5 mM of EDTA and DTPA to examine the impacts of plant growth response. The application of chelating agents increased ther availability of soil nutrients in the following order: DTPA > EDTA > control. Inorganic concentration of chinese cabbages in DTPA treatments consderably increased in nitrogen, phosphate, iron and aluminium contents than that of the other treatments. The optimal concentration of DTPA for vigorous plant growth as 0.5 mM. Thus, DTPA was more effective than other chelating agents for healty growth of cabbages and the availability of nutrients accumulated in plastic film house.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.943-948
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• 2012

This study was conducted to estimate the effect of nitrogen reduction by applying ryegrass and to determine the relationship between yield and nitrate concentration of soil solution for cucumber cultivation in plastic film house. Nitrogen levels with recovery of ryegrass ($42.3Mg\;ha^{-1}$) was 0, 50, 75, 100 % of 199 kg N $ha^{-1}$ as N recommendation by determining soil EC value. Yield and nitrate concentration in soil solution was investigated during cucumber cultivation. Yields of N treatments applied ryegrass showed 64.3, 70.9, 70.3, and $76.5Mg\;ha^{-1}$, respectively, it could reduce about 25-50% of nitrogen application compared to yield ($68Mg\;ha^{-1}$) of NPK plot applied 199 kg N $ha^{-1}$. Nitrate concentration in soil solution was average 26.0, 30.1, 41.4, $58.5mg\;L^{-1}$ during cucumber cultivation and was related between yield and average nitrate concentration of soil solution following as; $Y=49.3+0.63X+0.0034X^2$ ($R^2=0.778^{**}$). However, it needs to conduct extra-experiment due to high variation of nitrate concentration during cultivation periods.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.188-193
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• 2010

The aim of this study is to evaluate the effects of organic materials on soil organisms. Changes in the community structure, and population density of soil organisms (microbes, nematodes, and microarthropods) were studied in a Korean ginseng field. Phospholipid fatty acids analysis showed that the relative abundances of bacteria, fungi, and actinomycetes did not differ significantly. The aerobes/anaerobes ratio was the lowest in soils amended with leaf mold, indicating that the decomposition speed was slow. Further, the addition of leaf mold to the soil enhanced the saturated/monounsaturated fatty acid ratio and cyclopropyl fatty acid/precursor ratio, which indicated an increase in environmental stresses. Application of pig manure compost (PMC) had positive effects on the population density of nematodes, and negative effects on that of oribatid mites. The population densities of nematodes, and microarthropods remained relatively low in the plots that had been treated with leaf mold or pig manure compost. It is suggested that pre-planting soil management directed at enhancing the biological decomposition efficiency should be continued over a long period to increase the soil bioactivity in virgin soils.

• Tribology and Lubricants
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• v.12 no.1
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• pp.1-5
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• 1996

자성유체는 자연에서 추출한 것이 아니라 자화성(Magnetizability)과 유도성(Flowability)을 동시에 갖도록 합성한 특수액체이다. 자성유체는 1960년대 중반에 미국의 NASA에서 처음 개발된 이후로 윤활, 밀봉, 감쇄, 의료 등의 분야에서 응용연구가 많이 진행되었기 때문에 고도의 정밀도를 요하는 항공, 우주산업, 컴퓨터와 반도체 분야 등에서 실용화가 크게 진전되고 있다. 특수물질일 자성유체는 전기적으로 도체인 10nm 정도의 미세한 자기입자(Magnetic particles)에 코팅을 한 후, 이것을 물, 탄화수소, 플루오르카본, 에스터 등의 매개유체(Carrier Fluids)에 혼합시켜서 콜로이드 상태로 사용하게 된다. 자성유체는 미세한 자기입자들이 매개유체내에서 서로 충돌하면서 반발력을 발생시켜서 상호간에 늘 콜로이드 상태를 유지하고 있으며, 이 특수유체가 자기장의 영향을 받게 되면 점도가 증가하면서 특이한 성질을 갖게 된다. 상대 접촉 운동면에 경계마찰이나 혼합마찰을 하게 되면 윤활상태는 비교적 나쁘다. 이러한 마찰지역에 콜로이드상의 자성유체 윤활제를 공급하면 기존의 윤활제에 비하여 대단히 효과적으로 윤활을 할 수 있게 된다. 그러나 자성유체 윤활제가 마찰부위에 원활하게 공급하기 위해서는 미끄럼 마찰부에서 자기장을 잘 형성시킬 수 있는 도체이어야 하기 때문에 특별한 윤활 시스템 설계가 제시되어야 한다. 자성유체 윤활제는 합성으로 제조된 특수물질로 여러가지 장점을 갖고는 있으나 기존 윤활유와의 적합성, 마찰열, 밀봉압력 등의 조건에서 제한적으로 사용될 수 밖에 없으므로 항공, 우주 산업이나 석유 화학분야와 같이 특수 환경에서만 사용되고, 또한 기존의 광유계 윤활제에 비하여 대단히 고가하는 문제점을 갖고 있다. 그러나 윤활 마찰면의 다양화와 가혹한 사용조건은 자성유체 윤활제의 연구개발 필요성을 크게 증대시키고 있다.xed Effects Model)을 결정하고, 각각에 해당하는 통계모형을 구축하였다. 이 결과 (1) 업종 및 기업규모별로 그룹간에 유의한 특성이 발견되었으며, (2) R&D 및 광고투자는 기업의 시장성과를 설명하는 중요한 변수이나, (3) R&D 투자의 경우는 광고에 비해 불확실성이 존재하는 것으로 나타났고, (4) 수리모형에서 도출된 한계원리가 통계모형에서도 유효한 것으로 드러났다.등을 토대로 한 10대 산업을 육성하기 위하여 과학기술부는 기술수요조사를 바탕으로 49개 주요기술을 도출하여, 과학기술 일류 국가 실현, 국민소득 2만불 달성이라는 국가적 슬로건을 내걸고 “차세대 성장동력” 창출을 위한 범정부차원의 기획과 연구비의 집중투자를 추진하고 있다.달성하기 위해서는 종합류류 전산망의 시급한 구축과 함께 화물차의 적재율을 높이고 공차율을 낮출 수 있는 운송체계의 수립이 필요한 것으로 판단된다. 그라나 이러한 화물전용차선의 효과는 단기적인 치유책일 수밖에 없기 때문에 물류유통 시설의 확충을 위한 사회간접자본의 구축을 서둘러 시행하여야 할 것이다.으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한 시추공 내 물리검층과 정압주입시험에서도 확인된다.. It was resulted from increase of weight of single cocoon. "Manta"2.5ppm produced 22.2kg of cocoon. It is equal to 9% increase in index, as compared to that of control. In case

• Journal of fish pathology
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• v.28 no.3
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• pp.117-123
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• 2015

Economic loss by soft tunic syndrome of edible ascidian, Halocynthia roretzi has become a serious problem. Recently, it has discovered that the cause of this syndrome is infection by a protozoan parasite Azumiobodo hoyamushi. However, only a few studies have been conducted to control this parasitic disease. In a previous research, non-specific disinfectants have been found to be effective in controling the causative parasite. In an attempt to eradicate this causative parasite, organic acids were tested in this study to evaluate their in vitro and in vivo efficacy. In vitro tests showed that 8 different organic acids used in this study were moderately or highly effective with protozoan-killing effects ($EC_{50}=153{\sim}275{\mu}g/ml$). Despite weak in vivo penetration of organic acids into the tunic tissues, treatment with high concentration reduced the mortality of ascidian caused by infection the parasite, indicating that we might be able to develop a disinfection method using environmentally-friendly organic acids.

• Development and Reproduction
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• v.14 no.2
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• pp.123-129
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• 2010

Embryonic stem (ES) cells can self-renew maintaining the undifferentiated state. Self-renewal requires many factors such as OCT4, SOX2, and NANOG. It is previously known that OCT4 and SOX2 can bind to NANOG promoter and support Nanog gene expression in mouse ES cells by the detailed studies using the mouse Nanog promoter. Here, we constructed serial deletion mutant promoter-reporter constructs to investigate the human Nanog gene promoter in detail. The highest promoter activity was obtained in the 0.6 kb (-253/+365) promoter-reporter construct which includes the binding sites of OCT4 and SOX2. To further confirm contribution of OCT4 and SOX2 in Nanog gene expression, we introduced site- directed mutation(s) in the OCT4 and/or SOX2 binding sites of the human Nanog promoter 0.6 kb (-253/+365) and checked the influence of the mutation on the promoter activity using human EC cell line NCCIT. Mutation either in OCT4 binding site or SOX2 binding site significantly reduced the activity of Nanog promoter which directly confirmed that OCT4 and SOX2 binding is essential in human Nanog gene expression.

• Economic and Environmental Geology
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• v.45 no.1
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• pp.23-30
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• 2012

Major ions and nitrogen isotopic analyses were performed to determine the geochemical characters and to identify the source of nitrate of the shallow groundwater around agricultural field in the Youngdong area. The pH value of groundwater ranges from 60. to 8.2 (pH 7.2, mean). The average of EC, Eh and DO is 369 ${\mu}S/cm$ (70~729 ${\mu}S/cm$), 165.6 mV (29~383.2 mV), 4.3 mg/L (1.8~8.0 mg/L) respectively. The ion concentraion of groundwater was in the order of $Ca^{2+}$>$Na^{2+}$>$Mg^{2+}$>$K^{2+}$ and ${HCO_3}^-$>${NO_3}^-$>${SO_4}^{2-}$>$Cl^-$>$F^-$. Most of groundwater is Ca-$HCO_3$ type. The groundwater was affected by water-rock interaction in the shallow depth. Some groundwater is Ca-Cl or Na-$HCO_3$ (2.5%) type that was due to agricultural activities. The $NO_3$_N concetration of grondwater range from 10.2 mg/l to 26.9 mg/l, which show that this area is under nitrate pollution. ${\delta}^{15}N-NO_3$ value of the groundwater is the origins of are a combination of animal wastes and man-made fertilizers.

• Microbiology and Biotechnology Letters
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• v.33 no.4
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• pp.281-287
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• 2005

The endoinulinase gene (inu, 2.733 kb, EC 3.2.1.7) from Paenibacillus polymyxa was subcloned into an Escherichia coli-yeast shuttle vector with GALl promoter for the expression in Saccharomyces cerevisiae. The constructed plasmid, pYGENIU27 (8.6 kb) was introduced into S. cerevisiae SEY2102 cell and then the yeast transformant was selected on the synthetic defined media lacking uracil and on the inulin-containing media. The recombinant endoinulinase was predominantly localized in the periplasmic space of the yeast cell. The total activity of the endoinulinase reached 1.81 unit/ml by cultivation of yeast transformant on YPDG medium. The optimized conditions determined for the inulooligosaccharides (IOSs) production from inulin were as follows; pH, 8.0; reaction temperature, $45^{\circ}C$; inulin source, Jerusalem artichoke. Enzyme activity was stably maintained up to the pH of 10.0. Under the optimized condition and with endoinulinase of 36 unit/g-inulin, IOSs started to be produced after 10 min of enzymatic reaction. By the reaction with inulin, IOSs consisting of inulobiose (F2), inulotriose (F3), and inulotetraose (F4) were produced and F3 was the major product. Consequently, these data would be used as a fundamental parameters for the production of functional sweetener IOSs from inulin by recombinant yeast endoinulinase.

• Asian Journal of Atmospheric Environment
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• v.11 no.2
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• pp.96-106
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• 2017

In this study, measurements of size-segregated particulate matter (PM) emitted from the combustion of rice straw, pine needles, and sesame stem were conducted in a laboratory chamber. The collected samples were used to analyze amounts of organic and elemental carbon (OC and EC), water-soluble organic carbon (WSOC), humic-like substances (HULIS), and ionic species. The light absorption properties of size-resolved water extracts were measured using ultraviolet-visible spectroscopy. A solid-phase extraction method was first used to separate the size-resolved HULIS fraction, which was then quantified by a total organic carbon analyzer. The results show that regardless of particle cut sizes, the contributions of size-resolved HULIS ($=1.94{\times}HULIS-C$) to PM size fractions ($PM_{0.32}$, $PM_{0.55}$, $PM_{1.0}$, and $PM_{1.8}$) were similar, accounting for 25.2-27.6, 15.2-22.4 and 28.2-28.7% for rice straw, pine needle, and sesame stem smoke samples, respectively. The $PM_{1.8}$ fraction revealed WSOC/OC and HULIS-C/WSOC ratios of 0.51 and 0.60, 0.44 and 0.40, and 0.50 and 0.60 for the rice straw, pine needle, and sesame stem burning emissions, respectively. Strong absorption with decreasing wavelength was found by the water extracts from size-resolved biomass burning aerosols. The absorption ${\AA}ngstr{\ddot{o}}m $ exponent values of the size-resolved water extracts fitted between 300 and 400 nm wavelengths for particle sizes of $0.32-1.0{\mu}m$ were 6.6-7.7 for the rice straw burning samples, and 7.5-8.0 for the sesame stem burning samples. The average mass absorption efficiencies of size-resolved WSOC and HULIS-C at 365 nm were 1.09 (range: 0.89-1.61) and 1.82 (range: 1.33-2.06) $m^2/g{\cdot}C$ for rice straw smoke aerosols, and 1.13 (range: 0.85-1.52) and 1.83 (range: 1.44-2.05) $m^2/g{\cdot}C$ for sesame stem smoke aerosols, respectively. The light absorption of size-resolved water extracts measured at 365 nm showed strong correlations with WSOC and HULIS-C concentrations ($R^2=0.89-0.93$), indicating significant contribution of HULIS component from biomass burning emissions to the light absorption of ambient aerosols.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.931-944
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• 2013

With the expansion of EC and the development of culture industry, Web-site shopping of cultural products have become recognized as one of the major purchasing channels for customers, as well as one of the competitive distribution channels for film distributors or theater group. The research is to investigate the impact of information quality and user interface quality on information service satisfaction and online purchasing intention of cultural products. The results of this study are as follows: 1) Both information quality and interface quality have meaningful influence on information service satisfaction and purchase intention. 2) Information service satisfaction gives significant impact on online purchasing intention irrespective of the level of customer involvement. 3) Information quality has a meaningful influence on online purchasing intention in case of high level of customer involvement, while interface quality gives strong impact on online purchasing intention in case of low level of consumer involvement. In conclusion, there is a need to consider the level of customer involvement for building a successful marketing strategy of online purchase sites of cultural products.