• The Journal of Engineering Geology
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• v.32 no.3
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• pp.351-361
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• 2022

Numerical analysis performed to predict the behavior of Ipseok-dae columnar joints in Mudeungsan National Park to understand their stability and movement. The numerical analysis technique, 3DEC, is based on the discrete element method that can analysis discontinuities. The analysis used data for material properties derived from laboratory tests, which found that average density was 2.68 kN/m³, average normal stiffness was 3.15 GPa/m, average shear stiffness was 1.00 GPa/m, average cohesion was 0.51 MPa, and the average friction angle was 33°. The Ipseok-dae columnar joints were modeled on the basis of the field survey data for 15 joints located between the observation platform and the hiking trail. The numerical analysis assessed the behavior of each columnar joint by interpreting the displacement of the edges of its upper and lower surfaces. The greatest maximum displacement was found in columnar joint No. 6, and the greatest minimum displacement was found in joint No. 11. Analyzing the movements of five discontinuities in joint No. 11 indicated that the maximum displacement occurred at the 2nd level. The other levels were ordered 5th, 4th, 1st, and 3rd in terms of subsequent greatest displacements. Considering the total displacement in the 15 studied joints, the Ipseok-dae columnar joints are judged to be stable. However, considering the cultural and historical value of Mudeungsan National Park, it is regarded that the currents slope stability should be maintained by monitoring the individual rock blocks of the joints.

• Journal of Korean Electronics
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• v.14 no.11
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• pp.116-120
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• 1994

• Journal of Korean Electronics
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• v.16 no.1
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• pp.87-92
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• 1996

• 정보화사회
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• s.25
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• pp.8-9
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• 1989

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.44 no.10
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• pp.48-52
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• 2015

• Magazine of the Korean Society of Hazard Mitigation
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• v.3 no.4 s.11
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• pp.39-40
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• 2003

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.350-355
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• 2011

This paper gives an overview and developing status of the on-board Automatic Train Control (ATC) System employed to control the Urban Maglev vehicle in Korea. In the construction of demonstration line for Urban Maglev Program, the Daewoo Engineering Company (DEC) has participated as a supplier of the whole ATC System since 2009. According to the contract with Korea Rail Network Authority, DEC is under progress for the development of the whole ATC system including Safety Integration Level (SIL) assessment from the ISA, which is followed by the international standards IEC62278, IEC62279, and EN50129. Once the Urban Maglev Program is completed successfully in 2013, the developed system will be the first localized whole ATC system which has SIL assessment and commercial operation experience in Korea.

• The Journal of the Korean dental association
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• v.25 no.6 s.217
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• pp.578-587
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• 1987

The purpose of this was to examine the distribution and the bond failure of the acidetched ceramometal retainer (Maryland Bridge). 126 subjects who treated by faculty and residents of Department of Prosthodontics, Seoul National University Hospital from Dec. 1982 to Dec. 1986 were selected for this study. From the foregoing study author obtained the following conclusions. 1. A total of 135 restorations were placed in the mouths of patients ranging in age from 11 to 70 years (Man 62, woman 64) 2. Most restorations were applied to replace anterior teeth. 3. It was found that of the total number of bridges constructed 59.3 percent were the three-unit type. 4. Replacing one tooth missing was the most frequent cases(74.1 percent). 5. Of the total number of cases, 10.4percent showed bond failure. 6. The bond failure, author suggest, be due to one or more of mis-fit of framework, occlusion, material in itself, faulty case selection and lack of technique.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.295-298
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• 1998

We have investigated ionic conductivity and electrochemical stability of the electrolytes containing organic solvent. Ion conductivities were measured between 10 and 80$^{\circ}C$, and electrochemical stabilities were determined by cyclic voltammetry on glassy carbon, platinum and aluminum electrodes. Ionic conductivity of electrolyte(EC:DEC=1:1) with IM LiPF$\_$6/ shows better than that of the other electrolytes having Li salts. The IM LiBF$_4$-PC electrolyte exhibits good electrochemical stability. IM LiPF$\_$6/ (EC:DEC=1:1) and IM LiPF$\_$6/ (EC:DMC=1:1) electrolytes are used for the high capacity of battery system.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.379-384
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• 2003

DangSan Bridge of Seoul Subway No 2 was rebuilt by safety reason. From Dec 1996 to Dec 1999 we were in charge of permanent way design of this rebuilt project. Especially we applied maintenance free system on the bridge by Cologne Egg alternative (ALT1) base plate and CWR (Continuous Welded Rail) by ZLR(Zero Longitudinal Restraint) for 125m (south approach section), 120m long(north approach section). This thesis generally introduce for CWR by ZLR which was first adapted CWR system in Korea.