• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.11a
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• pp.43-48
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• 2002

Since the basement building like the communication hole and etc. is built under the ground where it is pressed by the water, the leakage happens due to the dried-shrinking crack, the sinking crack, the creation of the work-joint of the building and etc. caused by the character of the material and construction way of the reinforced concrete building. Especially, a lot of repair for the leakage cannot help but being taken in temporary way without any noticeable countermeasure. Therefore, this kind of repair is socially criticized many times that this is defective construction even if this costs a lot. The fundamental reason of the above mentioned symptoms can be found in the creation of the work-joint caused by the character of the concrete building, the limitation of the physical performance of the existing water-proof and repair material, the limitation of the construction, the limitation of the physical sustaining performance of the concrete building, the limitation(heat-injury, deterioration) of the constancy of the durability caused by aging and etc. Therefore, in this study, we would like to present the better understanding on the water-proof seal relating to the application at the spot and its test evaluation related data since the necessity of the establishment of the quality control standard and the performance testing way on the relevant water-proof seal is rising a lot to regulate the water-proof technology and the leakage repair technology in accordance with the growth of the demand on the facility.

• Nuclear Engineering and Technology
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• v.26 no.1
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• pp.126-139
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• 1994

Best-estimate thermal-hydraulic codes, CATHARE2 V1.2 and RELAP5/MOD3, hate been assessed against the BETHSY 6.2 tc six-inch cold leg break loss-of-coolant accident (LOCA) test. Main objective is to analyze the overall capabilities of the two codes on physical phenomena of concern during the small break LOCA i.e. two-phase critical flow, depressurization, core water level de-pression, loop seal clearing, liquid holdup, etc. The calculation results show that the too codes predict well both in the occurrences and trends of major two-phase flow phenomena observed. Especially, the CATHARE2 calculations show better agreements with the experimental data. However, the two codes, in common, show some deviations in the predictions of loop seal clearing, collapsed core water level after the loop seal clearing, and accumulator injection behaviors. The discrepancies found from the comprision with the experimental data are larger in the RELAP5 results than in the CATHARE2. To analyze the deviations of the two code predictions in detail, several sensitivity calculations have been performed. In addition to the change of two-phase discharge coefficients for the break junction, fine nodalization and some corrections of the interphase drag term are made. For CATHARE2, the change of interphase drag force improves the mass distribution in the primary side. And the prediction of SG pressure is improved by the modification of boundary conditions. For RELAP5, any single input change doesn't improve the whole result and it is found that the interphase drag model has still large uncertainties.

• Restorative Dentistry and Endodontics
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• v.26 no.2
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• pp.141-152
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• 2001

Eliminating the infecting bacteria of the root canal system and preventing reinfection must be the main objectives of all endodontic works. None of commercially available root canal sealers have the properties of desirable tissue compatibility and strong antibacterial activity. The purpose of this study is to develope an ideal root canal sealer using commercially available polyphosphate (polyP), Calgon, which is known to be antibacterial and safe. For the study. resin type AH26, zinc oxide eugenol type Tubli Seal. Ca(OH)$_2$ type Apexit as base sealers for polyP (0~3%) and para formaldehyde containing N2 as a control base were selected. Specimens (3$\times$4mm) of the sealers were prepared in a 37$^{\circ}C$ incubator for 3 and 10 days and their antibacterial activity against streptococci and black pigmented anaerobic rods was observed using an agar diffusion method. The result were as follows: 1. Among 3 day old root canal sealers. N2 as a positive control showed the strongest antibacterial effect. followed by AH26. Tubli Seal and. Apexit which barely showed antibacterial activity against the test bacteria. In contrast. 10 day old AH26 showed a greater antibacterial activity than 10 day old N2. 2. All sealer specimens showed a greater antibacterial activity against black pigmented anaerobic rods than streptococci. Three day old ones appeared to be more antibacterial than 10 day old ones except for Apexit. 3. As compared to N2, 3 day old AH26 demonstrated a similar antibacterial activity against black pig mented anaerobic rods but to a lesser extent to streptococci. Ten day old AH26 showed a greater antibacterial activity against black pigmented anaerobic rods than 10 day old N2. 4. As compared to AH26. Tubli Seal generally revealed a lower antibacterial activity but it showed a greater antibacterial activity aginst S. gordonii Challis. 5. Enhancement of antibacterial activity by polyP was more clearly observed when it was added to Ca(OH)$^{\circ}C$ based root canal sealers. Tubli Seal and N2. 6. The addition of polyP enhanced the antibacterial activity of 3 day old AH26 against S. gordonii G9B (16%) and Challis (29%), and P. gingivalis 2561 (24%) only. Moreover, polyP failed to increase antibacterial activity of 10 day old AH26 against the test strains but P. gingivalis A7A1 28(13%). 7. The addition of polyP increased the antibacterial effect of 3 day old Tubli Seal on several test bacteria including s. mutans GS 5 (50%). s. gordonii G9B (47%) and Challis (122%). and all the test strains of P. gingivalis (13~35%) except for 9 14K 1. The addition of polyP to 10 day old Tubli Seal increased antibacterial activity of the root canal sealer against most test strains. 8. 3 day old Apexit failed to show antibacterial activity. if any very little against S. mutans GS 5 and Pr. intermedia ATCC 49046. However. polyP increased its antibacterial activity by 50 and 69%, respectively. Increase of antibacterial activity of 10 day old Apexit by polyP was more clearly observed than that of 3 day old one.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.571-571
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• 2001

The purpose of obturating the prepared root canal can be simply stated as to eliminate all avenues of leakage from the oral cavity or the periradicular tissues into the root canal system and to seal within the system any irritants that cannot be fully removed during canal cleaning and shaping procedures. The ability to achieve three-dimensional obturation of the root canal system is primarily dependent on the quality of the canal cleaning and shaping and the skill of the clinician.(omitted)

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1053-1059
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• 2012

Barcode labels are being widely used for identifying products since they are cheap and easy to use. As the barcode labels are massively produced by seal printing, some labels have defects such as poor printing quality or data mismatch between barcode and the text. Barcode read errors and business errors caused by defected barcodes result in delay in logistics and increased processing costs. In this paper, we propose an on-line barcode verification system that uses image processing technique to verify the quality of labels at the production stage. The proposed system captures label images through the vision camera and then checks the print quality and verifies the combination of barcodes and texts in a label. If any defected label is found, the proposed system gives alarm signals and marks the defected labels so that they are removed at early stage of the production.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.375-383
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• 2005

The present paper describes the first development of a LOX/kerosene type turbopump in Korea. The liquid rocket engine, that the turbopump can be applied to, has a 30-ton(metric) level of vacuum thrust and employs a gas generator cycle. The turbopump consists of two single-stage centrifugal pumps, that is, LOX and kerosene pumps, and one single-stage impulse turbine. Inter-propellant seal(IPS) is located between the LOX pump and the kerosene pump to avoid any interaction between the propellants. A series of component and TPU(Turbopump Unit) test has been completed in the level of simulant propellants and ready for hot firing tests.

• Fire Science and Engineering
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• v.18 no.4
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• pp.93-102
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• 2004

The function of fire barrier penetration sealing is highly important to confine a fire propagation a fire severity within a fire area where the fire started. Especially for the penetration seals at the nuclear power plants with the long-term operated history, it is needed to make it clear that the conformance to the sealing requirements has been proven to guarantee the fire-resistive performance of fire barrier penetration parts. If there are any parts of fire barrier penetration sealing which can not meet the required rating for the fire endurance performance, the relevant parts must be modified to meet regulatory requirements. At this paper, the engineering analysis methodology was established to approximate the fire endurance rating for the fire barrier penetration seals. With this study, the method of engineering analysis to decide fire endurance rating for the fire barrier penetration seals was established and this way can be utilized to check the performance of the fire rating for the penetration seal at the domestic nuclear power plants.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3404-3412
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• 1994

The present study was undertaken to investigate the dry wear process and wear mechanism of the alumina ceramics in the purity variation which are used for the mechanical seal, roll, liner and dies. The wear test was carried out under different experimental condition using the wear testing device and in which the annular surface rubbed on dry sliding condition various sliding speed, contact pressure and sliding distance. In case of alumina purity 95%, there was speed range which wear loss increased rapidly owing to enlargement of heat impact force and temperature rise of wear surface. According as the alumina purity increased, wear loss decreased but alumina purity 85% with much void and defect had the most wear loss than any other alumina purity. The friction coefficient of sliding initial stage of wear curves has a large value but according to increase of sliding distance, it decreased owing to drop of the shear strength of wear surfaces.

• Natural Product Sciences
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• v.6 no.3
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• pp.126-130
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• 2000

Tiliacora racemosa Colebr. belonging to the family Menispermaceae, is the biggest storehouse of diphenyl bisbenzylisoquinoline (DBBI) alkaloids. Exhaustive chemical processing of the root of T. racemosa by the application of modern separation techniques yielded a DBBI alkaloid which was identified as tiliacorine using sophisticated spectroscopic methods (UV, IR, $^1H-NMR$, MS). Haematological study with tiliacorine proved that there was no abnormal haematological results in comparison with the normal values. Chronic toxicity study with tiliacorine revealed that the alkaloid is devoid of any hepatotoxic and nephrotoxic action.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.2
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• pp.109-114
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• 2015

We realize a color reflective display without any color filter and sub-pixelation concept, by which the full or single color realization is basically impossible. In this study, we use a 3-electrode on the lower substrate with indium tin oxide (ITO) glass. The width of a rib is $30{\mu}m$, a cell size is $150{\mu}m{\times}150{\mu}m$, and the space of lower electrodes is $10{\mu}m$. To get the single color, we drive this panel by a identical algorithm based on the movement of charged particle in color fluid within a cell with hermetic seal. According to the driving method, the lifetime of panel is different.