• Journal of the Korean Geosynthetics Society
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• v.6 no.2
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• pp.21-26
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• 2007

The tensile properties of geogrid are affected by such factors as temperature, specimen length, gauge length, testing speed and measuring equipment. The tensile strength of geogrids can be determined by ASTM 06637 and ISO 10319. The main differences between two testing methods are testing speed and specimen length. This paper presents the results of the wide-width tensile tests for three geogrids according to different specimen length and tension speed.

• Journal of the Korean Chemical Society
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• v.45 no.5
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• pp.454-460
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• 2001

The reaction of 3-methoxycarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline(7) with hydrazine hydrate gave 3-hydrazinocarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline(8). The reaction of compound 8 with alkyl (ethoxymethylene)cyanoacetates gave the [(quinoxalin-2-ylidene)ethanoyl]-1H-pyra-zoles(9). The reaction of compound 9b with N-alkylanilines provided the N-alkyl-(quinoxalin-2-ylidene)-N-phenylethanamides(10). Compounds 9 and 10 showed the tautomerism between the enamine and methylene imine forms in solution. The tautomer ratios were determined by the $^1H$ NMR.

• Journal of Astronomy and Space Sciences
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• v.3 no.1
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• pp.1-13
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• 1986

A long-term project(ten-year ; 1982-92) for the photoeletric observation in the UBV passbands of selected eclipsing binaries with P$\geq$10 days has initiated at Yonsei University Observatory using 40-cm and 61-cm reflectors. the instrumentatio used and the observation techniques and the reduction procedures applied to this investiagation are described. Out of 39 program stars, successful results have been obtained during our first two years for the 11 stars listed below, with the orbital period in days in the parenthesis, and the incomplete light curves of these stars are presented. SX Cas (36.57) AQ Cas (11.72) UU Cnc (96.71) RY Gem (9.30) V373 Cas (13.42) NY Cep (15.28) RX Cas (32.32) V396 Cas (15.28) ZZ Cnc (25.60) Zet Aur (982.2) Eps Aur (9885.) For the rest of the stars, the observations made in the first two years are not sufficient to attempt any meaning light curve construction ; some of the data are too fragmented and others show large scatter.

• Journal of Astronomy and Space Sciences
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• v.33 no.3
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• pp.237-246
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• 2016

We analyze the design and specifications of the Sun-and-Stars Time-Determining group of instruments (Ilseong-jeongsi-ui, 日星定時儀) made during the Joseon dynasty. According to the records of the Sejong Sillok (Veritable Records of King Sejong), Sun-and-Stars Time-Determining Instruments measure the solar time of day and the sidereal time of night through three rings and an alidade. One such instrument, the Simplified Time-Determining Instrument (So-jeongsi-ui, 小定時儀), is made without the essential component for alignment with the celestial north pole. Among this group of instruments, only two bronze Hundred-Interval-Ring Sundials (Baekgak-hwan-Ilgu, 百刻環日晷) currently exist. A comparison of the functions of these two relics with two Time-Determining Instruments suggests that the Hundred-Interval-Ring Sundial is a Simplified Sundial (So-ilyeong, 小日影), as recorded in the Sejong Sillok and the Seongjong Sillok (Veritable Records of King Seongjong). Furthermore, the Simplified Sundial is a model derived from the Simplified Time-Determining Instrument. During the King Sejong reign, the Sun-and-Stars Time-Determining Instruments were used in military camps of the kingdom's frontiers, in royal ancestral rituals, and in royal astronomical observatories.

• Journal of Astronomy and Space Sciences
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• v.29 no.4
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• pp.397-405
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• 2012

Astronomical Observations at Chungbuk National University Observatory (CBNUO) with an 1 m telescope have begun since April 2008, and Near-Earth Space Survey observations also have been started since November 2010, with a 0.6 m wide field telescope developed by Korea Astronomy and Space Science Institute. To improve observational efficiency, we developed a weather monitoring system enabling automatic monitoring for the weather conditions and checking the status of the observational circumstances, such as dome status. We hope this weather monitoring system can be helpful to more than 100 Korean domestic observatories, including public outreach facilities. In this paper, we present the statistic analysis of the weather conditions collected at CBNUO for 3 years (2009- 2011) and comparisons were made for clear nights between using only humidity data and both humidity and cloud data.

• Journal of Veterinary Clinics
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• v.3 no.1
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• pp.243-253
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• 1986

In recent years much attention has been paid to swine respiratory infection caused by Haemophilus(H.) Pleuropneumoniae with rapid expansion of pork industry in Korea. The organism may cause an acute respiratory infection with high morbidity and mortality, or it may also cause chronic persistent infection, resulting in loss of body weight. The present study was performed to observe the etiologic situation of H. Pleuropneumoniae infection by evaluating bacteriological, serological examinations with the lungs and sera collected from slaughtered pigs in Daegu city, respectively. In addition, antibiotic susceptibility test was carried out against the isolated strains of H. Pleuropneumoniae. The results obtained are summarized as follows : 1. Only 10 strains of H. Pleuropneumoniae were isolated from the 120 cases of swine lungs examined, and biological and biochemical characteristics of the isolates were identical with that of standard strains(serovar 1 to 6). 2. Out of 336 swine sera examined, 108(32.1%) were shown to be positive against H. Pleuropneumoniae by latex agglutination test. 3. Antibiotic susceptibility test revealed that 10 isolates of H. Pleuropneumoniae were sensitive to 16 kinds of antibiotic such as ampicillin, benzylpenicillin, piperacillin, cephalothin, cefazolin, cefamandol, cefoperagon, lactomoxycefa, tetracycline, minocycline, chloramphenicol, gentamicin, kanamycin, amikacin, colistin and nalidixic acid, whereas cloxacillin, erythromycin, kitasamycin, lincomycin, oleand-amycin, and bacitracin were resistent.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.10
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• pp.68-79
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• 1999

This paper describes an approach to collaborative design which focuses on the effects of individual activities on the overall design process. We utilize a new process modeling tool to define the process and then analyze and refine the process based on critical paths. This information is then shared over the Internet with all participants. The goal of this system is to detect critical errors at initial design stage and guide the designers to make better decisions based on the knowledge of the overall process. This system enables participating designers to publish his local process through an Internet bulletin board. Other members of the team can then provide feedback based on how the proposed process impacts their activities. The system provides a context-rich, persistent forum for collecting, preserving, and refining corporate expertise of the team. For example, designers can select any process from the bulletin board and use it as a template for his current project and then use it to maintain his own design history. This paper is based on the process modeling concepts of Design Roadamap and describe several key extensions in the area of CPM calculations and collaborative interfaces.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.6
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• pp.613-620
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• 2012

Rails are subjected to damage from rolling contact fatigue, which leads to defects such as cracks. Rolling contact fatigue damages on the surface of rail such as head check, squats are one of growing problems. Another form of rail surface damage, known as "Ballast imprint" has become apparent. This form of damage is associated with ballast particles becoming trapped between the wheel and the surface of rail. These defects are still one of the key reasons for rail maintenance and replacement. In this study, we have investigated whether the ballast imprint is an initiator of head check type cracks and effect of defect size using Finite element analysis. The FE analysis were used to investigate stresses and strains in subsurface of defects according to variation of defect size. Based on loading cycles obtained from FE analysis, fatigue analysis for each point was carried out.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.6
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• pp.621-625
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• 2012

Conventionally, to measure derailment coefficient of a railway wheel, strain gauges for lateral force measurement are attached to both side of the wheel. But narrow gap between railway wheel and traction motor makes it difficult to attache the strain gauges at the inner side of wheel. In this study, to overcome the hard accessibility to the strain gauge points by narrow gap, a new Wheatstone bridge connection method is presented by attaching all the strain gauges at the outer side of wheel with a new bridge connection. We evaluate the running safety of railway vehicles in accordance with railway safety regulations. The experimental results obtained shows higher sensitivity than conventional methods and the derailment coefficient measurement procedure becomes simpler.

• Water Engineering Research
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• v.6 no.2
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• pp.63-71
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• 2005

Nowadays Climate disasters are frequently happening due to occasional occurrences of EI Nino and La Nina events and among them, water shortage is one of the serious problems. To cope with this problem, climate model simulations can give very helpful information. To utilize the climate model for enhancing the water resources planning techniques, probabilistic measures of the effectiveness of global climate model (GCM) simulations of an indicator variable for discriminating high versus low regional observations of a target variable are proposed in this study. The objective of this study is to present the various analysis methods to find the suitable application methods of GCM information for Korean water resources planning. The basic formulation uses the significance probability of the Kolmogorov-Smirnov test for detecting differences between two variables. The various methods for adopting correct association, changing the window size, discrimination condition, and the use of temporally down scaled data were proposed to find out the suitable way for Korean water resources planning.