• 한국조경학회지
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• 제24권1호
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• pp.1-14
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• 1996

The purpose of this study was an analysis of the elementary school child's attitude and dangerous factors of play apparatuses n elementary schools. The results were summarized as follows; 1. 53.0% of the reply child thought that play apparatuses were dangerous, and 41.0% of the total reply had experienced accidents by apparatuses, the child under 10 had experienced the accidents manytimes. 2. The types of injuries most frequently occurred are falls from play apparatuses, and part of the body most frequently injured parts of the body are arms and legs. 3. The danger of fall in play apparatuses that is over 3M amounted 19.6%, it asked safety of bottom materials. 4. Destructed play apparatuses reached up to 20.0%, and rusted or decomposed apparatuses reached to 28.4%. 5. The distance of each apparatus were very close ; it was within 0.3~1.5M, which was 24.9%, it was very dangerous factor. 6. The most frequent hazards of educational play apparatuses are ; - inappropriate size of apparatuses(height, gap, thick etc.)- inappropriate shape and finished state(bad welding and cutting, projection part etc.)- unsuitable use of bottom material in playground and safety color.- insufficient use zone.-inappropriate maintenance and inspection(endurance passage, erosin of iron-ware and wooden ware, projection of foundation concrete)

• 한국산학기술학회논문지
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• 제4권3호
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• pp.183-188
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• 2003

본 연구는 Connector Mold의 Termina (리브)에 가스 모임으로 인한 미성형 및 웰드라인이 생성되어 이를 방지하기 위해 과다한 사출압력, 금형온도 및 수지온도를 높이므로 Burr둥의 불량현상이 발생하게된다. 따라서 연구에서는 진공성형시스템을 응용한 Connector Mold를 개발하기 위하여 사출성형의 중요한 인자가 되는 용융수지온도, 금형온도, 냉각조건을 최적 조건에서 진공압을 체계적으로 제어함으로 각 캐비티의 깊은 글 부분의 미충전 부분을 진공화 하여 충전불량을 해소하면서, 싸이클 시간을 단축시킬 수 있는 진공시스템을 연구개발 성형가공에 적용함으로 우수한 제품과 생산성 향상의 효과를 얻을 수 있다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.608-612
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• 2009

30톤급 액체로켓엔진 연소기 개발 기술을 바탕으로 75톤급 기술검증용 연소기 시제품을 제작하였다. 시제품 제작에서 검증하고자 하였던 일부 기계가공 공정 및 접합 기술들은 75톤급 연소기에서도 동일하게 적용할 수 있음을 확인하였다. 새롭게 설계된 연소기 헤드부는 새로운 공정을 적용하여 제작하였다. 기술검증용 시제품을 통해 확립된 공정 및 기술들은 대형 액체로켓엔진 연소기 제작 기술의 신뢰성을 향상 시킬 것이다.

• 한국해양공학회지
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• 제19권6호통권67호
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• pp.64-71
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• 2005

The welding methods have been applied to the most structural products used in the automobile, ship construction, and construction. The structure steel must have sufficient strength of structure; However, the mechanical properties of the welded part changes when it is welded. Therefore, the stability or life of the structure may be affected by the changed mechanical properties. The mechanical properties of the welded part must be examined in order to ensure the safety of structure. In this research, the SS400 steel and the STS304 steel were used to estimate the mechanical properties of the HAZ by weld thermal cycle simulation. In this study, the materials were used to examine the weld thermal cycle simulation characteristic, under two conditions: the drawing with diameter of $\Phi$10 and the residual stress removal treatment. To examine the mechanical properties by the weld thermal cycle simulation, the tensile test was carried out in room temperature. The crosshead speed was lmm/min.

• 한국해양공학회지
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• 제26권3호
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• pp.1-5
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• 2012

A complex energy saving device has been developed for middle class vessels. The propulsive performance of the developed device is described through a model test. The pre-swirl stator, which recovers the rotational energy of the propeller slipstream, is a well-known energy saving device for large vessels. The pre-swirl stator for a large vessel is usually cast as a part of the stern frame and has a high cost. The manufacture of a cast stator for an existing vessel is almost impossible. The complex device that was developed can be fitted on astern frame by welding. The model tests show a 4-6% efficiency gain for middle class vessels with the developed appendages compared to those with bare hulls.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1399-1406
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• 2011

As a result of the examination analyzed loop type of Detecting the Broken Rail Monitoring System as a part of prevention of train derailment, installed in the Seoul Metro No. 2 subway line 98.51m section which is Samsung to Seolleung, we found that it is possible to detect crack location(Thermit welding: 48.18m) within the margin of error of ${\pm}1m$ accurately As analysis of the first day, third day, fifty day, and seventh day periodically, we found that Fresnel reflection happened where the crack location 48.18m. However other 3 branches show loss by bending of optical cable(spread reflection from the outside impact).

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2082-2089
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• 2011

This study is examination of application on site for performance and stability of real-time broken rail detection equipment development system about connection, welded part occurring data errors of broken rail monitoring system. As a result of analysis about data collected in Seoul Metro No.2 Subway from Mar. 2010 to Jan. 2011, we found it is possible to detect crack location(Thermit welding) within the margin of error of ${\pm}1m$ accurately as the first attenuation was -1.2dB and the second was -1.3dB.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 봄 학술발표회논문집
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• pp.187-194
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• 2000

Weight reduction for an automobile body is being sought for the fuel efficiency and the energy conservation. One way of the efforts is adopting Ultra Light Steel Auto Body (ULSAB) concept. The ULSAB concept can be used for the light weight of an automobile door with the tailor welded blank (TWB). A design process is defined for the TWB. The inner panel of door is designed by the TWB and optimization. The design starts from an existing component. At first, the hinge and inner reinforcements are removed. In the conceptual design stage, topology optimization is conducted to find the distribution of variable thicknesses. The number of parts and the welding lines are determined from the topology design. In the detailed design process, size optimization is carried out to find thickness while stiffness constraints are satisfied. The final parting lines are determined by shape optimization.

• 수산해양기술연구
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• 제36권2호
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• pp.132-138
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• 2000

The effect of fluid flow on corrosion and erosion-corrosion of metal is a well-recognized phenomenon in pipelines and machinery equipment, and so on. Not only are fluid hydrodynamics important, but also the corrosiveness of the process or production stream affects the corrosion system. Recent research demonstrates that it is possible to erosion-corrosion(E/C) phenomena in terms of hydrodynamics, electrochemical corrosion kinetics and film growth/removal phenomena. Stress corrosion cracking behavior under cavitation erosion-corrosion of mild steel(SS41) was investigated of base metal and weldment under loaded stress. Main result obtained are as follows : 1) The cavitation erosion sensitivity of base metal affected weight loss is more susceptive than heat affected zone, 2) The corrosion sensitivity affected weight loss of welding heat cycle is less susceptive on stress corrosion under cavitation erosion-corrosion than stress corrosion.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.85-89
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• 2004

The inner side between HP stationary blades in #1 turbine of Nuclear Power Plant A is damaged by the FAC(flow assisted corrosion) which is exposed to moisture. For many years the inner side is repaired by welding the damaged part, however, FAC continues to deteriorate the original material of the welded blade ring. In this study, we have two stages to verify the integrity of stationary blade ring in nuclear power plant A. In the stage I, replication of blade ring is performed to survey the microstructure of blade ring. In the stage II, the stress analysis of blade ring is performed to verify the structural safety of blade ring. Throughout the two stages analysis of blade ring, the stationary blade ring had remained undamaged.