• Journal of Korean Society of Steel Construction
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• v.24 no.5
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• pp.571-582
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• 2012

Prestressed composite girders provide efficient composite action by applying prestress to the sub-encasing concrete. In this study, an enhanced prestressed composite girder with forms suspended from the steel girder is utilized. Long-term behavior of the prestressed composite girder is estimated using age-adjusted effective modulus method, which is verified experimentally using measurements obtained from an in-service bridge. Then, parametric study is carried out to investigate the influences caused by ambient temperature, humidity, prestressing and concrete casting date.

• Journal of the Korea Concrete Institute
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• v.11 no.6
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• pp.13-24
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• 1999

The external, unbonded prestressed concrete(PSC) members exhibit very different structural behavior from that of internal bonded PSC members because of eccentricity change and slip occurrence during loading process. The purpose of the present study is to propose the ultimate failure stresses of prestressing (PS) steels for those external unbonded PSC members. To this end, a comprehensive analysis has been made using the nonlinear finite element analysis program developed recently for external unbonded PSC members by authors. A series of major influencing variables have been included in the analysis. It was found that the span-depth ratio, neutral axis depth-effective depth ratio, load geometry, amount of ordinary steel, and prestressing steel ration have great influence for the ultimate failue stress of PS steel is preposed and is compared with experimental dat as well as existing formulas for internal unbonded members. The Comparison indicates that the proposed equation agrees relatively well with experimental data and that existing formulas including ACI and AASHTO equations show some discrepancies from experimental ones. The present study allows more realistic analysis and design of prestressed concrete structures with external unbonded tendons.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.151-154
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• 2005

A study was conducted to investigate safe testing on propulsion system, especially concentrated on effects of contaminants accumulation and transfer in LOX system. Several methods for system operation decreasing accidents caused by oxidizer leakage and contaminants accumulation was investigated. These methods can be applied to LOX system and other propellants system in liquid propellants propulsion system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.23-26
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• 2005

The method of decreasing the ecological risk for the LRE(Liquid Rocket Engine) test is developed, working on the cryogenic oxidizer and the high-boiling fuel(Kerosene). This Method is based on the study that contains a technical solution method and an accident occurrence range for decreasing of accident probability and damage. This paper contains schematic on the all risk circumstance bring to accident, block-diagram for an accident growth process in case of the propellant leakage, evaluation method of safety distance from test stand to residential area. It will be used to alternative method for the risk reduction of complex technical systems.

• Journal of Korean Orthopaedic Sports Medicine
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• v.7 no.1
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• pp.55-57
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• 2008

Isolated navicular fracture and dislocation of talonavicular joint is extremely rare. It is recommended closed or open reduction for displaced fracture. We reported one case of isolated tarsal navicular fracture and dislocation of the talonavicular joint, treated with open reduction and internal fixation using K-wires.

• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.157-166
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• 2003

IPPT(Integrated Propulsion Performance Test)s were carried out as a final stage of KSR-III(Korea Sounding Rocket-III) propulsion system development three kinds of engine with different injector faceplate were tested, therefore a engine with composite baffle was certified for a KSR-III launcher. Though a engine with STS baffle which was designed for verification of combustion instability suppression ability was not final design, due to the combustion tests with this engine, it can be described that baffle has capability to suppress combustion instability at ignition and at mainstage in the case of KSR-III combustor.

• Korean journal of food and cookery science
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• v.18 no.6
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• pp.684-691
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• 2002

The objectives of this study were to determine the consumption pattern and importance of Kimchi in our meals, and the preference of Kimchi. The 77.0% of the housewife respondents were preparing Kimchi at home. The reasons for not making Kimchi were ‘don't have time’(39.4%), ‘don't know how to make Kimchi’(18.2%) and ‘don't eat much’(18.2%). The amounts of daily Kimchi intake of the respondents were ‘less than 50g’(42.3%) or ‘50-100g’(29.8%). They are Kimchi because it was ‘delicious’(48.4%) or ‘habitual’(39.5%). The 70.0% of the respondents answered that Kimchi was important in each meal. The most respondents favored ‘moderate’ in the degree of fermentation(48.1%), hot taste(65.0%) and salty taste(72.4%). As the age of the respondents increased, they favored less sour, less hot and less salty taste. Baechu Kimchi(4.15), Chonggak Kimchi(3.89), Dongchimi(3.85), Kkaktugi(3.74), water Kimchi(3.67) were preferred by the respondents. The 73.97% of the respondents preferred Kimchi Jjigye. The 10- to 19-years old respondents preferred Kimchi Jjigye(52.8%), Kimchi pan cake(24.5%) and fried rice with Kimchi(17.0%).

• Journal of Korean Foot and Ankle Society
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• v.15 no.1
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• pp.18-21
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• 2011

Purpose: To evaluate the clinical and radiological results of internal fixation with tension band wiring for the fracture at the base of fifth metatarsal bone. Materials and Methods: From January 2008 to December 2009, 15 cases with displaced fracture at the base of fifth metatarsal were analyzed and average follow up period was 13.8 months. Lawrence classification was used to classify fracture type. We evaluated clinical results by American Orthopedic Foot Ankle Society (AOFAS) midfoot score and radiological results by union time. Complications was also checked. Results: According to classification, zone I fracture were 11 cases and zone II fracture were 4 cases. Bony union was achieved in all cases after 7 weeks. In the final follow-up, average AOFAS score was 94. There were no complications except hardware irritation. Conclusion: Satisfactory results were obtained after tension band wiring for the fifth Metatarsal base fracture in zone I fracture or comminuted zone II fracture for which it is not easy to be fixed with screw.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.389-392
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• 2004

It is clinically well known that pre-tension of wires increases the fracture stability in ring or hybrid external fixation. In some cases, additional half pin should be necessary to increase the stability when soft tissue impalement occurs during fixation. In this paper, the fracture stability of a hybrid external fixator system with different pre-tension effects and additional half-pins was analysed using FEM to investigate the effects of these pre-tension and half pin on the system stability quantitatively. 3-D finite element models of five different fixator frames were developed using by beam elements. In axial compression analysis, the fracture stiffness was increased maximally 62％ as the pre-tension increased. In torsion analysis, in the other hand, there is little variations in the fracture stiffness. Additional half pin increased the system stiffness about 200 ％. From the results, proper pre-tension and additional half pin would provide good methods to increase the fracture stability of the hybrid external fixator and provide more surgical options to minimize soft tissue damage at the fracture site.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.576-577
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• 2011

이상기후 변화에 따라 전력 수요량이 매년 증가하는 추세에 따른 전력 보유량이 줄어들고 있는 실정이다. 5차 전력수급 계획에 따르면 전력 소비량에 비해 전력공급 설비 증가량이 매우 부족한 실정이다. 이에 기존의 가공송전선인 ACSR에 전력송전 용량을 증가시킬 수 있는 방안으로 알루미늄 도체에 합금 원소를 첨가하여 특성을 향상시키나, 도체의 형상을 Round Type에서 Trapezoidal Type으로 변경함에 따라 도체의 점적률을 약 20~25% 향상시킴으로 전력송전 용량을 향상시킨 증용량 가공송전선 개발이 진행되고 있다. 또한 지지선을 고강도, 비자성 특성을 갖는 강선 및 고강도, 저 선팽창계수 특성을 갖는 복합재료를 사용함으로써 가공송전선의 이도 특성을 향상시킨 가공선 개발이 활발히 진행되고 있다.