• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.5
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• pp.224-226
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• 2005

In this paper, the secular changes of buried grounding electrodes was investigated; the electrodes are such facilities as grounding grid, grounding connector, grounding terminal and grounding rod etc.. The corrosiveness of removed substation grounding electrodes after commercial operation more than 50 years was measured and its conductivity deterioration trend was analyzed. The measuring results using three experimental methods were compared, finally the consideration for safe and economic grounding design were shown. As the result, it shows the maintenance necessity of grounding systems.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.676-681
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• 2000

This paper covers durability and field application of marine concrete which have been enhanced the resistance against deterioration in seawater. Fly ash concrete is applied to make the concrete with good durability. It is well known fly ash in concrete has a good performance preventing fro a sulphate attack and a steel corrosion. Several durability tests were performed to find characteristics of marine concrete which is proposed in this paper comparing with normal concrete. Field application was executed to compare results with laboratory test and to give a reliability to engineers. The project was supported by Ministry of Marine Affairs and Fisheries for two years.

• Journal of Chest Surgery
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• v.29 no.6
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• pp.655-659
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• 1996

Primary cardiac tumors are known to be rare. Of the benign primary tumors, rhabdomyoma predominates in neonates and infants. Tuberous sclerosis is found in hall of the patients with rhabdomyomas. Rhabdomyomas demonstrate benign pathological characteristics and may regress spontaneously that resection of the intracavitary obstructing portion of these tumors are recommended. We performed resection of intraatrial rhabdomyoma which had been obstructing mitral valve orifice and caused heart failure in a neonate. Postoperatively, fungal endocarditis developed and after 3 days, rapid growth and extension of the vegetation in the aorta obstructed the flow through the ascending aorta and resulted in hemodynamic deterioration.

• 한국문화재보존과학회:학술대회논문집
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• 2007.10a
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• pp.15-16
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• 2007

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.871-876
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• 1998

The SHOT PATCH System Remitar is a mortar shotcreting system which used fairly small machine and equipment, and is applied for shortcrete tunnel linings, in particular for small bore tunnels of aqueducts by the TBM(Tunnel Boring Machine) method, and for repairing tunnels suffering from spring water and deterioration. This study shows the characteristics of the new mortar shotcreting system, the SHOT PATCH System Remitar, which exhibits excellent shotcrete performance.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1998.11a
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• pp.108-111
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• 1998

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.167-168
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• 2022

본 논문에서는 접지계통에 사용되는 접속계수에 대한 열화특성 분석을 기술한다. 그 접지 시스템의 연결 방법은 IEC 표준에 명시되어 있습니다. 연결부의 열화 특성을 분석하기 위해 인자, 연결 인자를 소금물과 지하에 묻었을 때 열화 시험을 수행하였다. 테스트 연결 계수 C형 슬리브, 클램프 및 발열 용접이 있었습니다. 그 결과, 접속 인자의 대부분이 부식되었고, 전기적 요인이 발생하였다. 저항은 악화된 후에 감소했다. 분석 결과는 접지 시스템의 안전성을 확립하는 데 사용될 수 있다

• Journal of the Korean Graphic Arts Communication Society
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• v.30 no.1
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• pp.35-45
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• 2012

Polyacrylate dispersion(emulsion) as adhesive material was superior in quality such as preservation characteristics and reversibility. The tapes for repairing archival documents manufactured with four different types of formulation resulted in pH 7~8.8, soluble solid 50~52%, and viscosity 1,300~2,500 cps. Sample 4 of those was most excellent. Probably, sample 4 included inorganic materials such as MgO, silica gel, and zeolite. For selecting carrier of tape, tracing papers, were applied for manufacturing tapes and tested for adhesive strength and peel strength. Adhesive strength of tracing papers, was 3.1~3.8(N/10mm), 2.2~2.8(N/10mm), and 1.7-2.3(N/10mm), respectively. Peel strength was similar in all samples. To determine characteristic of conservation to the selected carriers, stability of deterioration was examined at conditions of $105^{\circ}C$ and $80^{\circ}C$ 65% for 7 days.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.6
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• pp.9-14
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• 2012

Currently a variety of efforts to conserve and restore the injured the Annal of the Joseon Dynasty are continued and many studies about the aging pathway of the beeswax-treated volume have being progressed. In this study, two chambers were set up to assess the influence of VOCs(Volatile Organic Compounds) generated in process of beeswax deterioration. One chamber was closed and the other was continuously ventilated in order to remove the VOCs. In results, the acid compounds of beeswax-treated Hanjis aged in closed chamber was more than that aged in ventilated chamber. The folding endurance of beeswax-treated Hanjis aged in closed chamber was lower than that aged in ventilated chamber. Accumulated acid compounds of beeswax-treated Hanji in closed chamber may cause accelerated aging and strength decrease. In conclusion, accumulated acid compounds can accelerate the aging of beeswax-treated Hanji and cause the severe deterioration of inside of beeswax-treated volume. Therefore, to preserve more safely beeswax-treated volumes of the Annals of the Joseon Dynasty, it is essential that VOCs emitted from beeswax-treated volume are ventilated.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.2
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• pp.322-329
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• 2009

Machinability of LAM(Laser Assisted Machining) has been studied for ceramics such as $Al_2O_3$, $Si_3_N4$ and $ZrO_2$ by $CO_2$ laser. It was possible to remove ceramics by PCBN tool because material became softening and deterioration by local laser beam irradiation. The advantage of LAM is the ability to produce larger material removal rates and tool life. But, for cutting of $Al_2O_3$ and $ZrO_2$, stage of laser power control was needed owing to thermal shock with high temperature of workpiece by laser power. And when $Si_3N_4$ was machined by LAM, $N_2$ gas spouted from surface of one cause of high temperature. Characteristics of LAM were analyzed using pyrometer, dynamometer, SEM and EDS to measure temperature of workpiece surface, cutting force, variation of machining surface and structure of lattice respectively. As the result of this study, it was found that machinability of LAM for ceramics in $CO_2$ laser and mechanism of LAM was different according to the kind of ceramics because of properties of materials.