• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.160-163
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• 2004

In domestic, various repair materials and method systems to keep up with these reinforced concrete deteriorated due to salt damage, carbonation, chemical decay et. developed and applied. However, on-site quality control of various repair materials and method systems isn't achieved desirably because it is depend completely on a men of experience' opinions above all else regardless of various on-site environments. In this background, mock up test with due regard to real on-site environments was performed to secure fundamental data for establishment of desirable on-site quality control. Mock up test using repair mortar analyzed from angles of construction methods, mechanical spraying pressures, W/M. Construction methods were designed manpower method and spraying method, spraying pressures were designed 32, 42, 52 psi, W/M were designed 14.4, 15.4, $16.4\%$. And compressive strength, Chloride ion diffusion coefficient, bond strength, SEM. of mock up test specimens were evaluated. In conclusion, we confirmed excellency of mechanical spraying pressures, fined extremely excellency of condition of spraying pressure 42 ps, W/M $14.4\%$ within this study. therefore the results of this study will be useful to provide fundamental data for establishment of desirable on-site quality control.

• 한국환경성돌연변이발암원학회지
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• 제9권1호
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• pp.13-22
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• 1989

The effect of novobiocin (NOV), and inhibitor of topoisomerase II, on ethyl methanesulfonate (EMS)-or bleomycin (BLM)-induced DNA repair synthesis was examined during the cell cycle of Chinese hamster ovary (CHO)-K1 cells. Three assays were employed in this study: cell survival, alkaline elution and unscheduled DNA synthesis. EMS was effective at killing CHO cells in G1 phase, wheras BLM preferentially killed cells in G2 and S phases. EMS induced the much more amount of DNA damage in G1 phase, while BLM induced in G2 phase than the other phases. The both of pre- and post-treatment with BOV inhibitied EMS- or BLM-induced DNA repair synthesis in G1 and G2 phases, and pretreatment with NOV inhibited more effectively than the post-treated group. These results suggested that CHO cells exhibited a differential sensitivity to cell lethality and DNA damage in relation to cell cycle according to used chemical agents, and that DNA topoisomerase II participated in an initial stage of DNA repair.

• 대한관절경학회지
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• 제2권2호
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• pp.181-184
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• 1998

저자들은 생체 분해성 Meniscus Arrow$^{(R)}$를 이용한 반월상 연골 봉합술후에 발생한 비세균성 활액막염을 최초로 경험하였다. 따라서 향후 Meniscus Arrow$^{(R)}$를 이용한 반월상 연골 봉합술 후에 활액막염이 발생할 수 있음을 고려하여야 하며, 이 경우에서 활액막 절제술로 좋은 결과를 얻을 수 있었기에 문헌과 함께 보고하는 바이다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.397-400
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• 2006

Most of the civil structures in Korea and abroad have many kinds of damages when they are facing over-loaded traffics, long-term serviceability, and severe environmental conditions. Repair, rehabilitation, and retrofit are important for maintaining the serviceability of structures. In recent year, VES-LMC has been widely used as repair material for bridge deck repair and rehabilitation, because the VES-LMC has a various benefits such as traffic opening after 3 hours of curing, higher durability and bond strength. In case of any structure repaired or rehabilitated with VES-LMC, those were influenced capacity of bond between the base layer of slab and VES-LMC as well as physical properties of each other materials. The capacity of bond depended on purity of interface, micro cracks, curing of VES-LMC and so like. A kind of popular concrete repair technique, High pressure water jetting equipment is extremely efficient at removing damaged concrete. Removing damaged or poor quality concrete from sensitive structures such as bridge, tunnels, multi-story car parking decks and runways, using the high pressure water jetting could remove damaged or poor quality concrete remaining healthy and sound concrete. Accordingly, the purpose of this study is that it was to evaluate effect of hydrodemolition on the bond strength of VES-LMC overlay compared with effects of other method such as breaker, untreated. Also, it was evaluated the effect of surface moisture.

• 한국건설순환자원학회논문집
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• 제4권3호
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• pp.322-329
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• 2016

본 연구에서는 콘크리트 구조물의 누수 균열 보수에 사용되는 재료에 대한 품질관리 방안으로 선행연구에 이어 후속 연구로 "온도 안정성 시험방법"을 제안하였다. 제안된 시험방법을 이용하여 5계열의 15 종류, 총 45개의 시험편을 대상으로 성능 평가한 결과 온도 안정성 시험에서는 저온($-20^{\circ}C$), 고온($60^{\circ}C$)의 다소 가혹 조건의 온도에서 얼었다 녹았다가 반복되면서 흘러내림, 체적변화, 색의 변화 등 다양한 재료 변화가 나타났고, 이에 대한 누수 여부 판별을 위하여 투수 시험한 결과 약 29%인 13개의 시료는 누수 되지 않았고, 약 71%인 32개 시료에서 누수되는 결과가 확인되었다. 이러한 결과는 현재 콘크리트 구조물의 유지보수에 사용되는 누수보수재료에 대한 온도 환경이 고려된 품질관리 기준 설정에 대한 필요성을 충분히 인식 할 수 있었으며, 콘크리트 구조물의 장기 내구성 확보를 위한 본 시험 방법인 "온도 안정성 시험방법"에 대한 표준적인 시험방법으로서의 활용 가능성을 확인하였다.

• 콘크리트학회논문집
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• 제24권4호
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• pp.361-368
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• 2012

보수 보강재는 강도, 안정성, 내구성, 모재와의 부착력 등 많은 특성이 필요하며, 최근 변형경화형 시멘트 복합체(strain-hardening cement-based composite, SHCC)가 기존의 재료를 대체할 수 있는 성능으로 많은 연구가 이루어지고 있다. 팽창형 SHCC는 팽창재를 이용하여 수축이 발생하는 SHCC의 단점을 보완하여 성능을 개선시킨 복합체로 이를 이용해 보강재의 성능을 만족시키면서 동시에 강도 증진 효과를 가져올 수 있을 것으로 예상된다. 따라서 이 연구에서는 SHCC 보강재의 강도, 팽창재 대체 여부 및 보강 두께를 변수로 하여 휨 성능을 평가하였으며, 실제 보강에 적용 시 기초 자료로 활용하고자 한다.

• 대한조선학회 특별논문집
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• 대한조선학회 2011년도 특별논문집
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• pp.12-16
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• 2011

During the shipbuilding construction, the repair works will be occurred by various reasons such as the natural disaster, mistakes of engineers or workers, defect of material, and so on. The one of the engineer's responsibilities is to design considering every possibility and to prevent the repair works due to the mistakes during construction stages, but actually it is very difficult and impossible to avoid every mistake. However, it is also the responsibility of engineers to find the best solution for the unavoidable mistakes which is to maintain the capacity of vessel and guarantee the safety for the repair works considering the construction schedules and economic cost. In this paper, it will be introduced the brief of repair works to the structural damage of the moon-pool structure in drillship which is built in our shipyard. For the verification of the structural strength, the fatigue analysis has been carried out based on the guide of Classification society. Furthermore, the modifications of structure design and welding procedure have been applied to avoid the stress concentration in the moon-pool structure.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.621-624
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• 2008

콘크리트 구조물에 적용되는 보수재료는 적용되는 환경요인에 따라 품질특성이 다르게 나타난다. 국내의 보수재료에 대한 내구성 평가는 다양한 환경요인에 따른 시험법의 미비로 내구성에 대한 품질성능이 확보되지 않은 실정이다. 본 연구에서는 국내에서 생산되는 보수재료에 대하여 적용환경에 따른 동결융해저항성능을 BS EN 13687에 준하여 시험하였고, 국내시험규격(KS F 4716)과 비교 분석하였다. 연구결과 건습반복과 염수침지동결융해 시험 후의 부착강도 값은 보수재료의 종류 및 시편의 크기에 따라 다소 큰 차이가 나타났다. 보다 양호한 보수재료의 품질관리를 위해서는 적용환경에 따른 다양한 동결융해저항시험방법에 대한 규격제정이 요구된다.

• 대한족부족관절학회지
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• 제5권1호
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• pp.5-12
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• 2001

Purpose: To find out the priority of which procedure has had a better outcome both clinically and radiographically between the two groups, one is treated by primary repair and the other by modified Brostr$\ddot{o}$m's procedure, by comparing the postoperative ankle joint stability and the patient's degree of satisfaction. Material and methods: 16 cases were taken into consideration whose number of severed ligaments were at least two or more of the lateral collateral ligaments of the ankle, and also were confirmed intraoperatively. Among them, 8 cases were treated with primary repair and the other 8 cases were treated with primary repair and the other 8 cases by modified Brostr$\ddot{o}$m's procedure. Results: There was no distinguishable difference for the patient's degree of satisfaction between the two procedures above mentioned. In 3 cases treated with primary repair, functional instability was observed. In case of postoperative ankle joint stability, 7 of 8 cases treated by modified Brostr$\ddot{o}$m's procedure has revealed increased joint stability. And 3 of 8 cases which were treated by primary repair have showed postoperative residual instability. Conclusion: Actually, the severed ligament can not maintain its normal strength though several months has elapsed, and possible residual instability could be remained. Therefore, it can be expected that modified Brostr$\ddot{o}$m's procedure also would be a .good method in obtaining suitable ankle joint stability as well as subtalar joint stability because of its reinforcement using extensor retinaculum.

• Tribology and Lubricants
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• 제38권3호
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• pp.93-100
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• 2022

Micro-light emitting diode (micro-LED) displays offer numerous advantages such as high brightness, fast response, and low power consumption. Hence, they are spotlighted as the next-generation display. However, defective LEDs may be created due to non-uniform contact loads or LED alignment errors. Therefore, a repair process involving the replacement of defective LEDs with favorable ones is necessitated. The general repair process involves the removal of defective micro-LEDs, interconnection material transfer, as well as new micro-LED transfer and bonding. However, micro-LEDs are difficult to repair since their size decreases to a few tens of micron in width and less than 10 ㎛ in thickness. The conventional nozzle-type dispenser for fluxes and the conventional vacuum chuck for LEDs are not applicable to the micro-LED repair process. In this study, transfer conditions are determined using a micro stamp for repairing micro-LEDs. Results show that the aging time should be set to within 60 min, based on measuring the aging time of the flux. Additionally, the micro-LEDs are subjected to a compression test, and the result shows that they should be transferred under 18.4 MPa. Finally, the I-V curves of micro-LEDs processed by the laser and hot plate reflows are measured to compare the electrical properties of the micro-LEDs based on the reflow methods. It was confirmed that the micro-LEDs processed by the laser reflow show similar electrical performance with that processed by the hot plate reflow. The results can provide guidance for the repair of micro-LEDs using micro stamps.