• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.607-612
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• 2005

Check valves playa vital role in the operation and protection of nuclear power plants. Check valves failure in nuclear power plants often lead to a plant transient or trip. An overview of the failure history of check valves needs to identify key area where resources can be best applied to further improve their reliability, and provide cost effective means for failure reduction. The analysis of historical failure data gives information on the populations of various types of check valves, the systems they are installed in, failure modes, effects, methods of detection, and the mechanisms of the failures. The results presented are based on information derived from operating records, nuclear industry reports, manufacturer supplied information. A majority of check valve failures are caused by improper application. Failure modes are identified for swing and lift check valves. Failures involving improper seating and valve disc stuck comprised the largest percentage of failures.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.144-150
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• 2008

This research aims to develop parts for advanced fuel/oil filtering re-circulation applicable to this kind of regulation proof engines. These parts can playa role of converting traditional air emission type crankcase into recovery type crankcase so that the engine can deal with environmental regulations, which do not allow minimal amount of toxic gas discharge. For the experiment, test method and specially made testing equipment are prepared. The results showed that oil separation efficiency of the cone type CCV(Crank Case Ventilation) system was higher than one of cylinder type both in bench test and in engine.

• Journal of the Korea Furniture Society
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• v.17 no.3
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• pp.45-55
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• 2006

The change of consumers' lifestyles causes frequent study on beds along with growth of economy, improvement of education and increase of dwelling in new towns and nuclear family. Beds are frequently developed in recent years since consumers' lifestyles increasingly change caused by transformation of types of dwelling, influence of western lifestyle, and increase uses of a bed. Also, this transformation causes needs for research on bed designs. A Bed is an essential item in a life since people spend one third of a day in Also, in contemporary, the ages of consumers are varied from infants to seniors. The study examines the importance of beds which playa major role in households. Moreover, the purpose of this study of beds focused on surface materials, colors, and designs is suggesting bases for future developments.

• Toxicological Research
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• v.23 no.3
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• pp.189-196
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• 2007

Cytochrome P450 (P450) enzymes are the major catalysts involved in the biotransformation of various drugs, pollutants, carcinogens, and many endogenous compounds. Most of chemical carcinogens are not active by themselves but they require metabolic activation. P450 isozymes playa pivotal role in the metabolic activation. The activation of arylamines and heterocyclic arylamines (HAAs) involves critical N-hydroxylation, usually by P450. CYP1A2 plays an important role in these reactions. Broad exposure to many of these compounds might cause carcinogenicity in animals and humans. On the other hand, P450s can be also involved in the bioactivation of other chemicals including alcohols, aflatoxin B1, acetaminophen, and trichloroethylene, both in humans and in experimental animals. Understanding the P450 metabolic activation of many chemicals is necessary to develop rational strategies for prevention of their toxicities in human health. An important part is the issues of extrapolation between species in predicting risks and variation of P450 enzyme activities in humans.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2002.11a
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• pp.136-136
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• 2002

A rat (Rottus norvegicus) infected with C. hepatica was trapped incidentally. At necropsy, grossly yellowish-white nodules were scattered on the liver surface. Microscopically, granulomatous and fibrotic nodules containing eggs and/or adult worms of C. hepatica were detected in the liver. Septal fibrosis forming pseudolobules was observed as a diffuse change throughout the liver. In double staining with immunostaining of -SMA and toluidine blue, myofibroblasts and mast cells were generally observed within the fibrous septa with mast cells being along the myofibroblasts. In this case, we hypothesized that myofibroblast and mast cell might playa role in septal fibrosis of rat liver induced by C. hepatica infection.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.9 no.1
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• pp.1-7
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• 2005

The genomes of organism are being published in an enormous speed. The genomes has a lot of intronic regions, and repeats constitute a substantial part of that. Repeats playa crucial role in DNA finger-printing, and detecting certain genomic diseases, such as Huntington disease, which has a high number of CAG repeats. Also, they throw important clues about the evolutionary history. Repeats are in two types, Tandem Repeats and Interspersed Repeats. In this paper we address ourselves to the problem of detecting Primary Tandem Repeats, which are tandem repeats that are not contained in any tandem repeats. We show that our algorithm takes O(n log n) time, where n is the length of genome.

• Journal of Digital Convergence
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• v.5 no.2
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• pp.91-98
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• 2007

Destination marketing organizations (DMO) have been building up the cyber city in the WWW. Website for DMO is a core channel to promote regional attractions. This research suggests the issue of criteria for evaluating DMO's performance in the Internet. The method of evaluation focuses on the structure in perspective of linkage based on small world theory and direct network. Convention & Visitors & Bureau (CVB) in tourism and travel industry playa role to promote and held the international meeting and exhibitions. CVB's websites evaluated according to web link structure and performance.

• International Journal of Human Ecology
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• v.5 no.1
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• pp.35-43
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• 2004

The purposes of this study are to examine effects of household characteristics and risk tolerance attitude on risk tolerance behavior and to investigate the effect of risk tolerance attitude and behavior on financial satisfaction. For this study, data were collected during October of 2001 through a popular Web site for women in South Korea (www.azoomma.com). The participants in this study were 609 housewives, resulting in 607 with usable data. Multiple regression and path analysis were conducted using the SPSS for Windows. Findings suggest that the greater is risk tolerance attitude, the greater is risk tolerance behavior and those who exhibit more risk tolerance behavior tend to be more satisfied with their personal financial situation. It implies that risk tolerance behavior playa positive role in predicting financial satisfaction. The results have implication for family economists and educators in developing educational program and presenting strategic to increases financial well-being, and also for financial counselors and planners in suggesting portfolio advice to their client

• Speech Sciences
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• v.7 no.3
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• pp.87-98
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• 2000

Timing in speech is determined by many factors. In this paper, we introduce and discuss some factors that have generally been regarded as important in speech timing. They include stress, syllable structure, consonant insertion or deletion, tempo, lengthening at clause, phrase and word boundaries, preconsonantal vowel shortening, and compensation between segments or within phonological units (e.g., word, foot), compression due to the increase of syllables in word or foot level, etc. and each of them may playa crucial role in the structuring of speech timing in a language. But some of these timing factors must interact with each other rather than be independent and the effects of each factor on speech timing will vary from language to language. On the other hand, there could well be many other factors unknown so far. Finding out and investigating new timing factors and reinterpreting the already-known timing factors should enhance our understanding of timing structures in a given language or languages.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.237-241
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• 2004

We perform numerical experiments on supernova-driven turbulent flows in order to see whether or not supernovae playa major role in driving turbulence in the interstellar medium. In a $(200pc)^3$ computational box, we set up, as initial conditions, uniformly magnetized gas distributions with different pairs of hydrogen number densities and magnetic field strengths, which cover the observed values in the Galactic midplane. We then explode supernovae at randomly chosen positions at a Galactic explosion rate and follow up the evolution of the supernova-driven turbulent flows by integrating numerically the ideal MHD equations with cooling and heating terms. From the numerical experiments we find that the density-weighted velocity dispersions of the flows are in the range of 5-10 km $s^{-l}$, which are consistent with the observed velocity dispersions of cold and warm neutral media. Additionally, we find that strong compressible flows driven by supernova explosions quickly change into solenoidal flows.