• Journal of Advanced Marine Engineering and Technology
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• v.32 no.4
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• pp.542-549
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• 2008

The evaporation heat transfer coefficient and pressure drop of R-22 and R-407C in a horizontal copper tube were investigated experimentally. The main components of the refrigerant loop are a receiver, a compressor, a mass flow meter, a condenser and a double pipe type evaporator (test section). The test section consists of a smooth copper tube of 6.4 mm inner diameter. The refrigerant mass fluxes were varied from 100 to $300\;kg/m^2s$ and the saturation temperature of evaporator were $5^{\circ}C$. The evaporation heat transfer coefficients of R-22 and R-407C increase with the increase of mass flux and vapor quality. The evaporation heat transfer coefficients of R-22 is about $5.68{\times}46.6%$ higher than that of R-407C. The evaporation pressure drop of R-22 and R-407C increase with the increase of mass flux. The pressure drop of R-22 is similar to that of R-407C. In comparison with test results and existing correlations, correlations failed to predict the evaporation heat transfer coefficient of R-22 and R-407C. therefore, it is necessary to develope reliable and accurate predictions determining the evaporation heat transfer coefficient of R-22 and R-407C in a horizontal tube.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1197-1206
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• 2005

Vibrio vulnificus is an opportunistic pathogen that causes a septicemia and expresses numerous virulence factors, in which luxS and smcR are genes encoding for components responsible for quorum-sensing regulation. In the present study, null mutants were constructed with lesions in each or both of these two genes from the V. vulnificus Vv$\Delta$Z strain, which is a lacZ$^{-}$ and chloramphenicol/streptomycin-resistant derivative of the wild-type ATCC29307 strain, and their phenotypes related to virulence were compared with those of the parental cells. $LD_{50}$ and histopathological findings of luxS-, smcR-, or luxS- smcR- deficient mutant were not different from those of the parent strain, a lacZ-deficient streptomycin-resistant strain in mice. However, time of death in mice was delayed, and numbers of bacteria survived in bloodstream after intraperitoneal injection in mice were decreased by mutation, especially luxS and smcR double mutant (VvSR$\Delta$ZSR). These phenomena were supported by increased serum sensitivity and delayed bacterial proliferation in both murine blood and iron-restricted medium. These results suggest that the luxS and luxR homologous genes in V. vulnificus could playa role in bacterial survival in host by enhancing proliferation and adjusting to changed environment.

• Journal of Electrochemical Science and Technology
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• v.5 no.1
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• pp.1-18
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• 2014

Li-air cell is an exotic type of energy storage and conversion device considered to be half battery and half fuel cell. Its successful commercialization highly depends on the timely development of key components. Among these key components, the catalyst (i.e., the core portion of the air electrode) is of critical importance and of the upmost priority. Indeed, it is expected that these catalysts will have a direct and dramatic impact on the Li-air cell's performance by reducing overpotentials, as well as by enhancing the overall capacity and cycle life of Li-air cells. Unfortunately, the technological advancement related to catalysts is sluggish at present. Based on the insights gained from this review, this sluggishness is due to challenges in both the commercialization of the catalyst, and the fundamental studies pertaining to its development. Challenges in the commercialization of the catalyst can be summarized as 1) the identification of superior materials for Li-air cell catalysts, 2) the development of fundamental, material-based assessments for potential catalyst materials, 3) the achievement of a reduction in both cost and time concerning the design of the Li-air cell catalysts. As for the challenges concerning the fundamental studies of Li-air cell catalysts, they are 1) the development of experimental techniques for determining both the nano and micro structure of catalysts, 2) the attainment of both repeatable and verifiable experimental characteristics of catalyst degradation, 3) the development of the predictive capability pertaining to the performance of the catalyst using fundamental material properties. Therefore, under the current circumstances, it is going to be an extremely daunting task to develop appropriate catalysts for the commercialization of Li-air batteries; at least within the foreseeable future. Regardless, nano materials are expected to play a crucial role in this field.

• Korean Journal of Remote Sensing
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• v.21 no.3
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• pp.173-188
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• 2005

The present study aims to derive and compare narrow and broad bandwidths of ocean color sensor’s algorithms for the study of monitoring highly dynamic coastal oceanic environmental parameters using high-resolution imagery acquired from Multi-spectral Camera (MSC) on KOMPSAT-2. These algorithms are derived based on a large data set of remote sensing reflectances ($R_{rs}$) generated by using numerical model that relates $b_b/(a + b_b)$ to $R_{rs}$ as functions of inherent optical properties, such as absorption and backscattering coefficients of six water components including water, phytoplankton (chl), dissolved organic matter (DOM), suspended sediment (SS) concentration, heterotropic organism (he) and an unknown component, possibly represented by bubbles or other particulates unrelated to the first five components. The modeled $R_{rs}$ spectra appear to be consistent with in-situ spectra collected from Korean waters. As Kompsat-2 MSC has similar spectral characteristics with Landsat-5 Thematic Mapper (TM), the model generated $R_{rs}$ values at 2 ㎚ interval are converted to the equivalent remote sensing reflectances at MSC and TM bands. The empirical relationships between the spectral ratios of modeled $R_{rs}$ and chlorophyll concentrations are established in order to derive algorithms for both TM and MSC. Similarly, algorithms are obtained by relating a single band reflectance (band 2) to the suspended sediment concentrations. These algorithms derived by taking into account the narrow and broad spectral bandwidths are compared and assessed. Findings suggest that there was less difference between the broad and narrow band relationships, and the determination coefficient $(r^2)$ for log-transformed data [ N = 500] was interestingly found to be $(r^2)$ = 0.90 for both TM and MSC. Similarly, the determination coefficient for log-transformed data [ N = 500] was 0.93 and 0.92 for TM and MSC respectively. The algorithms presented here are expected to make significant contribution to the enhanced understanding of coastal oceanic environmental parameters using Multi-spectral Camera.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.307-312
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• 2004

Diversity of the bacterial communities and the relation between community structure and components of waste­water were analyzed by 16S rRNA-based molecular techniques. Clone libraries of the 16S rDNAs from the sludges were constructed by PCR and cloning. The 1,151 clones from a sludge sample of sewage treatment plant were clustered into 699 RFLP phylotypes and the 1,228 clones from the wastewater disposal plant of chemical industry were clustered into 300 RFLP phylotypes. Shannon-Weiner diversity indices of two sampling sites were 8.7 and 6.1, indicating that the bacterial community structure of sewage treatment plant was more diverse than that of wastewater disposal plant of chemical industry. Forty clones belonging to predominant RFLP types were selected and sequenced. Seventy percent (28 clones) of the sequenced clones were related to the uncultured bacteria in public databases. The ${\beta}-Proteobacteria$ dominated in the bacterial communities of investigated two sludge samples. 16S rDNA sequences of the sewage treatment plant were similar to those of other activated sludges, while the bacterial community in wastewater disposal plant of chemical industry rep­resented the strains identified from high-temperature, anaerobic, hydrocarbon-rich, and sulfur-rich environ­ments. This result suggested that bacterial communities depended upon the components of wastewater.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.401-410
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• 2020

This study is to conduct a 12-month f/u survey on changes of metabolic syndrome (MetS) components according to the resting heart rate (RHR) in patients with essential hypertension (HTN) without cardiovascular disease (CVD) complication. We used the KorHR (Korean Hypertension Registry) data and a total of 951 subjects were analyzed using the R statistical program. As a result of this study, it was found that the risk and changes of MetS components differs according to the RHR group with first and revisit hypertensive patients. Therefore, guidelines for customized RHR control for first and revisit hypertensive patients should be prepared. Also, it is necessary to prepare various interventions to control the RHR. Through this, it is intended to prevent the occurrence of CVD caused by HTN, which is a representative chronic disease, to improve the quality of life of patients and their families as well as to contribute to increasing the efficiency in the health care.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.174-176
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• 2008

HYOSUNG manufactured and tested 1kw class PEFC systems to generate electrical and thermal energy for each residential usage. In particular, HYOSUNG developed Power conditioning system that performs about 91% electrical conversion ratio specified in 1kW class PEFC systems. Prior to system integration, we tested each performances of components to derive control issues from it. In addition, we have been developing the adequate simulator to describe and predict system performance. In this paper, we verified HYOSUNG's 1kW class PEFC systems are valid for residential energy sureces by testing the characteristics of systems and performances of main component.

• Journal of Digital Convergence
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• v.7 no.4
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• pp.57-65
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• 2009

This study explored the current supply status on Contents Technology R&D(research and development) and friendly function Game Industry targeting to elderly consumers. The game contents including the functional components are categorized the sixth category of CT R&D's fundamental planning. The function game targeting to elderly focused on emotional and physical recovering to barrier, user friendliness, simplicity and certainty of game performance. The purpose of game participation are health, well-being, psychological wellness and communication. The functional game consisted of various version procedure by socio-demographic, the accessibility to game media and device.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.1
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• pp.41-44
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• 1993

This study was conducted to investigate the chemical components of culm that influencing the resistance to lodging and the in vitro digestibility in indica type rice plants. Indica type rice plants with three levels of lodging resistance were used; resistant type (RT), intermediate type (IT) and susceptible type (ST). For each type there were four varieties. Culm length was shorter in RT and longer in ST (98.1 cm vs. 151.8 cm). Silica content in the culm was highest in RT and lowest in ST (11.0% vs. 7.6%). There was no difference in the level of acid detergent lignin (ADL) between the 3 levels of lodging. For the 12 straw samples, in vitro organic matter digestibility (IVOMD) was negatively correlated with silica content (r = -0.664, p<0.05) but ADL had no significant effect (r = -0.454, p>0.05). Digestibility was more closely correlated with the sum of silica and ADL (r = -0.747, p<0.01) than silica alone. It was concluded that rice plants showed resistance to lodging when the culm was short and its structure was reinforced with larger quantities of silica. However these silicified straws were less digestible.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.1
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• pp.65-65
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• 1992

Recently many organizations have attempted to build hypermedia systems to expand their working areas to internet-based virtual work places. It is thus important to manage corporate hypermedia documents effectively. Metadata play a critical role for managing these documents. This paper identifies metadata roles and components to build its schema. Furthermore a meta-information system HyDoMiS(Hyperdocument Meta-information System) is proposed by the use of this metadata schema. HyDoMiS performs three functions metadata management search and reporting The metadata management function is concerned with workflow document and database. The system is more likely to help implement and maintsain hypermedia information system effectively.