• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.251-252
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• 2012

Recently, the growing interest in organic microelectronic devices including OLEDs has led to an increasing amount of research into their many potential applications in the area of flexible electronic devices based on plastic substrates. However, these organic devices require a gas barrier coating to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency OLEDs require an extremely low Water Vapor Transition Rate (WVTR) of $1{\times}10^{-6}g/m^2$/day. The Key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required ($1{\times}10^{-6}g/m^2$/day) is the suppression of defect sites and gas diffusion pathways between grain boundaries. In this study, we developed an $Al_2O_3$ nano-crystal structure single gas barrier layer using a Neutral Beam Assisted Sputtering (NBAS) process. The NBAS system is based on the conventional RF magnetron sputtering and neutral beam source. The neutral beam source consists of an electron cyclotron Resonance (ECR) plasma source and metal reflector. The Ar+ ions in the ECR plasma are accelerated in the plasma sheath between the plasma and reflector, which are then neutralized by Auger neutralization. The neutral beam energies were possible to estimate indirectly through previous experiments and binary collision model. The accelerating potential is the sum of the plasma potential and reflector bias. In previous experiments, while adjusting the reflector bias, changes in the plasma density and the plasma potential were not observed. The neutral beam energy is controlled by the metal reflector bias. The NBAS process can continuously change crystalline structures from an amorphous phase to nano-crystal phase of various grain sizes within a single inorganic thin film. These NBAS process effects can lead to the formation of a nano-crystal structure barrier layer which effectively limits gas diffusion through the pathways between grain boundaries. Our results verify the nano-crystal structure of the NBAS processed $Al_2O_3$ single gas barrier layer through dielectric constant measurement, break down field measurement, and TEM analysis. Finally, the WVTR of $Al_2O_3$ nano-crystal structure single gas barrier layer was measured to be under $5{\times}10^{-6}g/m^2$/day therefore we can confirm that NBAS processed $Al_2O_3$ nano-crystal structure single gas barrier layer is suitable for OLED application.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.3
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• pp.359-366
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• 1993

Molds are eucaryotic, multicellular, multinucleate, filamentous organisms that reproduce by forming asexual and sexual spores. The spores are readily spread through the air and because they are very light-weight and tend to behave like dust particles, they are easily disseminated on air currents. Molds therefore are ubiquitous organisms that are found everywhere, throughout the environment. The natural habitat of most molds is the soil where they grow on and break down decaying vegetable matter. Thus, where there is decaying organic matter in an area, there are often high numbers of mold spores in the atmosphere of the environment. Molds are common contaminants of plant materials, including grains and seeds, and therefore readily contaminate human foods and animal feeds. Molds can tolerate relatively harsh environments and adapt to more severe stresses than most microorganisms. They require less available moisture for growth than bacteria and yeasts and can grow on substrates containing concentrations of sugar or salt that bacteria can not tolerate. Most molds are highly aerobic, requiring oxygen for growth. Molds grow over a wide temperature range, but few can grow at extremely high temperatures. Molds have simple nutritional requirements, requiring primarily a source of carbon and simple organic nitrogen. Because of this, molds can grow on many foods and feed materials and cause spoilage and deterioration. Some molds ran produce toxic substances known as mycotoxins, which are toxic to humans and animals. Mold growth in foods can be controlled by manipulating factors such as atmosphere, moisture content, water activity, relative humidity and temperature. The presence of other microorganisms tends to restrict mold growth, especially if conditions are favorable for growth of bacteria or yeasts. Certain chemicals in the substrate may also inhibit mold growth. These may be naturally occurring or added for the purpose of preservation. Only a relatively few of the approximately 100,000 different species of fungi are involved in the deterioration of food and agricultural commodities and production of mycotoxins. Deteriorative and toxic mold species are found primarily in the genera Aspergillus, Penicillium, Fusarium, Alternaria, Trichothecium, Trichoderma, Rhizopus, Mucor and Cladosporium. While many molds can be observed as surface growth on foods, they also often occur as internal contaminants of nuts, seeds and grains. Mold deterioration of foods and agricultural commodities is a serious problem world-wide. However, molds also pose hazards to human and animal health in the form of mycotoxins, as infectious agents and as respiratory irritants and allergens. Thus, molds are involved in a number of human and animal diseases with serious implication for health.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.218-231
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• 1999

Pyramidal cells in the hippocampal CA area were recorded from and filled with neurobiotin in anesthetized rats. The extent of their dendrites and the electropharmacological properties of membrane as well as the effect before and after neurobiotin injection were examined. Pyramidal cells had a high resting membrane potential, a low input resistance, and a large amplitude action potential. A afterhyperpolarization was followed a single action potential. Most pyramidal cells did not display a spontaneous firing. Pyramidal cell displayed weak inward rectification and anodal break excitation in response to negative current injection into the cell. Membrane properties of recorded neurons before and after neurobiotin injection with consecutive current injection were compared. Some properties were significantly increased after labelling(P>0.05); the duration and amplitude of sustained AHP, input resistance, and the number of action potentials for simultaneous intra- and extracellular stimulations. Neurobiotin-filled neurons showed pyramidal morphology. Cells were generally bipolar dendrite processes ramifying in stratum lacunosum-moleculare, radiatum, and oriens.

• Research in Plant Disease
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• v.23 no.3
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• pp.249-255
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• 2017

The rice blast fungus is a representative model phytopathogenic fungus in which Gene-for-Gene interaction with host rice is applicable. After 1980, eight differential varieties have been constructed and classified to analyze the race of rice blast isolates in Korea. However, since there is limited information about the genetic background of rice blast resistance genes within the Korean differentials, scientific analysis on the emergence of new race or resistance break down was difficult. Recently, a differential system has been developed using monogenic resistance lines to understand the interactions of pathogen race and rice resistance genes. In this study, a total of 50 isolates were selected from four different races isolated in Korea, and they were inoculated into monogenic lines. As a result, the isolates in the same race classified by the Korean differential system reacted differently in single monogenic lines. This suggests that the isolates categorized as the same race group contains different avirulence genes and furthermore, it is presumed that the Korean differential system is difficult to provide useful information for breeding program. For this reason, introduction of differential system using monogenic resistance lines is required in addition to the current system.

• Journal of Korean Society of Transportation
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• v.28 no.6
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• pp.33-42
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• 2010

Recently, the reduction of greenhouse gases(GHG) for climate change is the most important international issue. In order to control efficiency GHG emission rate reduction, it is essential to establish GHG emission inventory preferentially. The emission of ships that are emitting its $CO_2$ in international waters is becoming chief among the issues which country is put under an obligation. In the IMO reports, shipping is estimate to emit 1,046million tonnes of $CO_2$, which corresponds to 3.3% of global emission during 2007. International shipping is estimated to have emitted 870 million tonnes, about 2.7% of global emission of $CO_2$ in 2007. In this study, the general information of GHG emission, based on fuel consumption statistic, Tier 1, and the emission inventory is calculated to break down in to domestic and international emission. The GHG emission from ships in Korea was total 31,646 Gg $CO_2$-eq in 2009, which is included fishing, Korea flag coastal ship, Korea flag ocean going ship and foreign flag ships. And domestic emission and international emission was 5,398Gg $CO_2$-eq, 7,630Gg $CO_2$-eq and foreign flag ship was 18,618Gg $CO_2$-eq respectively.

• Journal of KIISE:Information Networking
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• v.31 no.1
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• pp.81-90
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• 2004

A Mobile Ad Hoc Network (MANET) is a collection of wireless mobile nodes dynamically self-organizing in arbitrary and temporary network topologies without the use of any existing network infrastructure. The AODV (Ad Hoc On-Demand Distance Vector) Protocol is one of the typical reactive routing protocols, in that mobile nodes initiate routing activities only in the presence of data packets in need of a route. In this paper, we focus upon the local repair mechanism of AODV. When a link is broken, the upstream node of the broken link repairs the route to the destination by initiating a local route discovery process. The process involves the flooding of AODV control messages in every node within a radius of the length from the initiating node to the destination. In this paper, we propose an efficient local repair scheme for AODV called AFLRS (AODV-based Fast Local Repair Scheme). AFLRS utilizes the existing routing information in the intermediate nodes which have been on the active route to the destination before a link break occurs. AFLRS can reduce the flooding range of AODV control messages and the route recovery time because it can repair route through the intermediate nodes. For the performance evaluation of the proposed AFLRS, we have simulated the local repair mechanisms by using NS2 and AODV-UU. The performance results show that AFLRS can achieve faster route recovery than the local repair mechanism of AODV.

• Journal of Science and Technology Studies
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• v.18 no.2
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• pp.95-133
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• 2018

Since the beginning of the millennium, 'Maker Movement' has been active throughout the world. Today, there is a maker fair every year in major cities of the world including Seoul, and the number of attendees is increasing day by day, so it can be seen as a kind of maker 'phenomenon'. The positive implication of the maker's movement is that it attempts to break down the monopoly of manufacturing and to restore the rights and capabilities of citizens as makers. Today, highly developed industrial capitalism has a tendency to structurally paralyse citizens, to tie their hands and feet, and to degenerate into consuming entities only. Therefore, it can be said that the maker movement has structural tensions in the relationship of neoliberal manufacturing culture. This study is an attempt to actively interpret the maker movement in terms of "critical making". The maker movement can trace its origins to "counterculture" and "new communalism" that emerged in the United States in the 1960s and 1970s. On the other hand, there is criticism that the maker movement can fall into another technology utopianism and function as an area of consumer society, and mobilize it in the direction of activating consumerism. Although the maker's movement is amorphous due to its characteristics and it is currently in progress, it is difficult to make crude definition yet. However, as the citizens who have been defined only as consumers of science and technology, are newly emerging as producers of makers, there have been great changes in the topography of science and technology and civil society. So the scientific implication of the maker movement is great in that it shows the possibility of causing it.

• Journal of the Korean Geographical Society
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• v.40 no.6 s.111
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• pp.730-747
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• 2005

This study examines relationships between climatic factors and spatial-temporal patterns and recent changes of tropical night phenomenon(TN) occurring through nighttime stages in South Korea. Frequencies of daily TN at different times of night are extracted from long term(1973-2004) 6 hourly nighttime(9PM and 3AM) temperature and daily minimum temperature data at 61 weather stations. Temporally, the occurrences of TN are more pronounced in the evening(9PM) and during the Changma Break period(late July - early August). Spatially, the TNs in the evening frequently occur in the urbanized inland cities at low latitudes due to urban heat islands, whereas the TNs in the middle of night(3AM) or at dawn frequently appeared along the coastal areas within 30km from ocean due to the thermal inertia of ocean. By contrast, the evening(dawn) TN is not seen in the highlands whose elevation is greater than 800m(300m) along the Taebaek and Sobaek mountain ridges due to temperature lapse rates with height Correlation and multivariate regression analyses reveal that the impacts of human or physical climatic factors, such as latitude, elevation, proximity to ocean, and population density, are diverse on the frequencies of TN according to nighttime stages. Recent temporal changes of the late Changma period and intensified urbanization during the 1990s have increased the occurances of TN in urban areas. Therefore, strategies to mitigate the increasing urban TN should be prepared in the near future.

• Journal of Korean Society for Atmospheric Environment
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• v.7 no.1
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• pp.55-65
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• 1991

The study was performed to select a adaptable tree species under stressed field conditions where there are a industrial plants operating with a number of smoke stacks emitting pollutants, such as hydrogen fluoride and sulfur dioxide. As a result of the study, a tree species selected are due to construct a forest belt in a zones near industrial plants to reduce the concentrations of air pollutants. The concentrations of atmospheric hydrogen fluoride and sulfur dioxide were very higher at experimental sites near industrial plants (air-pollution sites) than at control site. The leaves of 7 tree species grown at air pollution sites contained more sulfur and, specially, fluorine than at those control site. Among the tested tree species, Ligustrum japonicum Thunb. and Euonymus japonica Thunb. grown at air pollution sites did not at all break out a foliar injury but appeared to be healthy, as well as those grown at control site. Acer pseudo-sieboldianum Kom., Pinus virginiana Mill., Larix leptolepis Gordon., Pinus koraiensis Sieb. et Zucc., Pinus strobus L., Picea abies Karst and Ligustrum obtusifolium Sieb. et Zucc., however, showed a severe fluoride-type foliar injury such as necrosis on tip or margin of leaves, etc. Fluorine found in leaves was proved to be correlated to sulfur found in leaves whereas index of foliar injury hadn't a good correlation to pollutants found in leaves. It appears that Euonymus japonica Thunb., Ligustrum japonica Thunb., Platanus acerifolia Willd, Chamaecyparis pisifera Endl., Populus tomentiglandulosa T. Lee and Sophora japonica L. grown at both experimental sites had a high value of percent survival whereas Pinus virginiana Mill., Pinus koraiensis Sib. et Zucc., Koelreuteria paniculata Laxm. and Alnus hirsuta Rupr. had an extremely low value of that. In comparison with control site, the percent tree height increments in Chamaecyparis pisifera Endl., Ligustrum japonicum Thunb., Quercus acutissima Carruth., Populus tomentiglandulosa T. Lee, Pinus thunbergii Parl and Euonymus japonica Thunb. and the percent upmost root diameters in Populus tomentiglandulosa T. Lee, Chamaecyparis pisifera Endl., Euonymus japonica Thunb., Ligustrum japonicum Thunb., Betula platyphylla var. japonica Hara and Pinus thunbergii Parl. cultivated at air polluted sites showed very high value above 90%, respectively. A significant negative correlation (r=-0.662) was recognized between the index of foliage injury and the percent collective character, which was the mean of tree characters such as percent survival, percent tree height increment and percent upmost root diameter increment which compared to those at air polluted site with those at control site. Based on the percent collective character Ligustrum japonicum Thunb., Euonymus japonica Thunb., Chamaecyparis pisifera Endl., Populus tomentiglandlosa T. Lee, Betula platyphyla var. japonica Hara and Platanus occidentalis L. have large value about 90%, respectively. Therefore, the results indicate that this tree species are adaptable species in air polluted regions. For better understanding of the adaptable tree species, furthur studies concerning the effects of various air pollutants on the tree growth are required.

• Korean Journal of Construction Engineering and Management
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• v.16 no.3
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• pp.152-164
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• 2015

Enhancing clarity and transparency of the pricing guide for technical services for public construction works enables the prediction and reimbursement of the service cost for project owners and bidders, while it would also yield benefits for engineers who carry out the construction tasks. In order to improve the global competitiveness of construction service industry, the government revised its pricing guide for techical services for construction works recently, moving away from its previous percentage-of-construction-cost method towards the Cost Plus a Fee Method. However, since the Cost Plus a Fee Method results in the rise of the service price by 153%~197%, there is the need for a review on the method and basis of the adjustment in order to avoid controversies regarding the application of the revised method. In this context, this paper analysed the 2014 revision of the pricing guide for technical services for public construction works through comparison with foreign cases including those of the US and the UK. The analysis yielded the conclusion that, while the shift towards Cost Plus a Fee Method which is widely used in advanced economies is a very meaningful change in large measure, certain aspects still remain problematic. Unlike in advanced economies, the detailed break-down shows the direct labor cost includes certain indirect expenses. Also, indirec expenses are admitted so comprehensively as to include overhead costs and technology royalties. These problems results in redundant estimation of certain expenses, and obstructs transparency in spending details. This paper proposes various improvement measures to address these issues.