• Corrosion Science and Technology
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• v.8 no.4
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• pp.133-138
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• 2009

For the corrosion protection of the natural gas transmission pipelines, two methods are used, cathodic protection and coating technique. In the case of cathodic protection, defects are embrittled by occurring hydrogen at the crack tip or material surface. It is however very important to evaluate whether cracks in the embrittled area can grow or not, especially in weld metal. In this work, on the basis of elastic plastic fracture mechanics, we performed the CTOD testing with various test conditions, such as testing rate and potential. The CTOD of the base metal and the weld metal showed a strong dependence of the test conditions. The CTOD decreased with decreasing testing rate and with increasing cathodic potential. The morphology of the fracture surface showed the quasi-cleavage at low testing rate and cathodic overprotection. The low CTOD was caused by hydrogen embrittlement at crack tip.

• ETRI Journal
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• v.32 no.1
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• pp.62-67
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• 2010

In this paper, an ultra-wideband internal antenna for use in mobile applications is proposed. The proposed antenna has symmetrical bi-arm structures printed on the top and bottom of the substrate, and it occupies a compact area of 10 mm ${\times}$ 10 mm ${\times}$ 1 mm. The designed antenna has an impedance bandwidth from 3 GHz to 12 GHz and near omnidirectional radiation patterns over the frequency band of interest. The group delay between two antennas fabricated using the proposed design is less than 0.8 ns, and the maximum gain variation is about 3.16 dB.

• Journal of Power System Engineering
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• v.21 no.4
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• pp.26-33
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• 2017

In this paper, we developed a control algorithm to maximize the cleaning performance and the cleaning efficiency of the underwater cleaning robot platform which has been developed for various cistern environment in the industrial field. Through these research and development, we have presented the operation and application of underwater cleaning robots that have been developed, and contributed to commercialization. Finally, this results were verified the effectiveness through actual field experiments.

• Mycobiology
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• v.37 no.4
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• pp.310-312
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• 2009

A total of 82 isolates of Colletotrichum species were obtained from anthracnose symptoms of highbush blueberry trees grown in the Gochang area of Korea during a disease survey in 2008. Out of the isolates, 75 were identified as Colletotrichum gloeosporioides and the others as C. acutatum based on their morphological and cultural characteristics. Twenty six of C. gloeosporioides isolates produced their teleomorph Glomerella cingulata in PDA culture. Three isolates of each C. gloeosporioides and C. acutatum caused anthracnose symptoms on the leaves by artificial inoculation, which were similar to what was observed in the orchards. Previously in Korea, only C. gloeosporioides has been reported as causing anthracnose in blueberries. This is the first report that C. acutatum causes anthracnose in the highbush blueberry in Korea.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.590-597
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• 1997

In this work, a new type of UV flame detection system was developed. In order to measure the performance of UV flame detector, various kinds of experiments was performed. The results show that the maximum response time of the UV flame detector is 0.2 seconds when the detection distance is one meter The advantages of this system include wide area, high speed response and high sensitivity. After testing the W flame detector in engine compartment it detected fire within 0.09 seconds and extinguished within 5 seconds. Hence, the UV flame detector can be applied in automatic fire suppression system for automobiles.

• The Korean Journal of Soil Zoology
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• v.2 no.1
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• pp.41-58
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• 1997

According to the related references, up to now the systematic studies on the ants from Mt. Moak have not been professionally surveyed yet. On order to classify the the ants from Mt. Moak, authors had collected the ants in this area from Octorber, 1993 to June, 1995. Examining all the collections, 44 species of 23 genera of 17 tribes under 3 subfamilies were identified.

• The Journal of the Acoustical Society of Korea
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• v.18 no.3E
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• pp.26-29
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• 1999

In this paper, we propose a new voice coding using only the features of the face image such as mouth height(H), width(W), rate(R=W/H), area(S), and ellipse's feature(P). It provides high security and is not affected by acoustic noise because we use only the features of face image for speech. In the proposed algorithm, the mean recognition rate for the vowels approximately rises between 70% and 96% after many tests.

• ETRI Journal
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• v.29 no.3
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• pp.393-395
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• 2007

Analytic modeling and computational simulation for the protection of DTV from cognitive radio interference are performed. Protection is achieved by using the protection ratio, which is derived through system modeling and its analysis. On the frequency coordination between digital TV and cognitive radio, an analysis in a co-channel environment, in a rural area in Korea, is performed.

• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1203-1206
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• 2003

Analysis of health-related microbes called probiotics was performed by capillary electrophoresis. A rapid and easy characterization for two important probiotics, Saccharomyces cerevisiae and Enterococcus feacalis, was obtained in the running buffer containing poly(ethylene oxide). Quantitation of probiotic (Saccharomyces cerevisiae) shows a good linearity between the peak area versus the concentration of microbe. From the comparison of electropherograms of antidiarrhea, it was found that capillary electrophoresis could be employed for the quality control and quality assurance for the production of a medicine containing the probiotics.

• Journal of Forest and Environmental Science
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• v.34 no.5
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• pp.382-387
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• 2018

Two newly recorded gnaphosid spiders, Haplodrassus pugnans (Simon 1880) and Zelotes longipes (Koch 1866), are taxonomically described and illustrated from Korea. Both species were collected in the mountainous area with a pitfall trap.