• Archives of Plastic Surgery
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• 제36권5호
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• pp.642-648
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• 2009

Purpose: Hexadactyly without thumb is a rare congenital anomaly of the hand where six triphalangeal digits are symmetrically distributed without thumb. Contrary to mirror hands, triphalangeal six digits are symmetrically distributed on each side at the midline with well - differentiated carpal bones, extensor tendons, one ulnar and one radius. The authors developed a new surgical technique based on a three - dimensional concept to correct the hexadactyly and applied to 2 cases of hexadactyly with good functional and aesthetic results. Here we document the surgical technique and its result. Methods: A 16 month old male patient visited our clinic with chief complaints of bilateral hexadactyly deformity. On physical examination most radial first and second digits showed no opposition and adduction motion on both side hands. Radiography showed 6 triphalangeal digits with normal development of carpal, radial and ulnar bone. Right side abnormality was corrected by removal of most radial side extra - digit, rotation and migration of 2nd ray to thumb position and creation of 1st web by transposing a mid - palm based rectangular palmar flap as in Snow & Littler procedure which has been being applied for correction of 1st web syndactyly in cleft hand deformity. Seven months later, left side abnormality was also corrected with the same procedure. Results: Postoperative appearances of the both hands were satisfactory. Flexion, extension, opposition and grasping were possible with the pollicized 2nd ray. Pinching power was 3.0 kg 15 months after surgery and 2.5 kg 22 months after in right hand respectively. Conclusion: In correction of hexadactyly deformity, satisfactory aesthetic and relevant functional results can be expected with authors' newly developed technique: removal of most radial digit, rotation and migration of 2nd digit to thumb position as well as creation of the 1st web space by transposition of mid - palm based rectangular flap.

• Design & Manufacturing
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• 제15권1호
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• pp.8-13
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• 2021

Excavators are construction machines used for digging soil, transporting soil, dismantling buildings and clearing the ground at construction sites. There are various attachments attached to the arm end of the excavator and used for various operations. There are the most common types of buckets attached for excavation and other types of attachments used for foresting, road cleaning, snow removal, and waste disposal. When multiple types of work are done at the same time, several attachments must be replaced and a device called a quick coupler is used to reduce replacement time. Although a quick coupler reduces the replacement time of the Attachment, it is necessary to attach safety devices to prevent unintentional detachment of attached attachments during the operation. To prevent the attachment from leaving or falling regardless of the operator's intention, support is installed in the hook of the bucket pin and controlled through a separate hydraulic cylinder to ensure safety. When attaching an attachment, it shall be attached without any action. This study is intended to verify the design validity of safety devices to prevent falls of attachments occurring at construction sites.

• Corrosion Science and Technology
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• 제22권5호
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• pp.322-329
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• 2023

There are a variety of heat exchangers used in automobiles, such as shell and tube heat exchangers, double tube heat exchangers, and plate heat exchangers. Most of them are water-cooled to prevent engine overheating. There have been reports of corrosion damage to these heat exchangers due to continuous wetting caused by external temperature differences, road pollutants, and snow removal. In addition, galvanic corrosion, which occurs when two dissimilar materials come into contact, has been identified as a major cause. In this study, corrosion characteristics and galvanic corrosion behavior of Al alloy (AA3003, AA4045 and AA7072) used in automobile heat exchangers were analyzed. Effective clad materials for heat exchanger tubes and fins were also evaluated. It was found that AA7072 should be applied as the cladding material for fin AA3003 and that AA4045 was suitable as a cladding material for tube AA3003 because this clad materials application was the most effective clad design to delay the occurrence of pinhole in the tube. Main factors influencing galvanic corrosion dissolution were found to be galvanic corrosion potential difference and galvanic corrosion current density.

• 미술이론과 현장
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• 제13호
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• pp.7-33
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• 2012

The memory of the Korean War is about the time period when people lived toughly during evacuation, due to being exposed to the natural climate such as intense cold or heat without any protection, leaving their comfortable home and living in temporary built shelters which were barely enough to avoid the wind. 'Death is concealed and only the figures of evacuation for survival were expressed, just as how the government ordered. Since the experience of the battlefield is personal and fragmentary, that is broken into pieces, it does not have compatibility. As war is a distorted experience that cannot be placed in a big picture, it is not possible to take a view of the war's big picture. Having this individualized experience as a common collective memory is an issue and it is the will that people tries to pursue. The reason why the evacuees from north to south, and as well as from the south to further south were all able to be adopted as the theme of artworks due to the military action that emptied the occupied territories of the North Korean Army under the forced removal command. In such situations, the natural state of the 'snow' was like a symbol of the 1.4 Recession. The group of people who were thrown into the intense cold displaced the war damage of loosing their base livelihood, and symbolized the obedient citizens who faithfully follow their government's command. The figure of advocating anti-communism is projected as a figure of a refugee during cold winter-time and it contains ones past which he or she obeyed its own country's commands. Evacuation, especially the evacuation during the winter is a visual device that can confirm these kinds of country's command. The consequences were same for the artists as well. Therefore, the situation being communal could be found due to the individual experiences during war are ideological. The image of the refuge shown in the picture played the role of strengthening the consciousness of defecting to South Korea into the meaning of the 'Finding Freedom.' I would like to express that the reason of them leave their home during the harsh winter is in order to avoid the oppression of the Communist Party. The evacuation that people went through was not to 'Finding Freedom', but 'To Survive'. Later, this evacuation has been imprinted as a behavior of choosing free Republic of Korea, which was an ideological issue. Anti-communism was the rule of survival in South Korea society, and people have the tendency to remember what they want to remember. As it is not the people who possesses an incident, but the memory that possesses ones, people cover their memory with disguised plots in order to forget the violence and to live a different prologue. They share the incident of violence as a hurtful memory. The tragedy of the Korean War was the result of Ideology and being in between the powerful nations' rights, but the violence during the war has been depicted as a natural disaster, which was the evacuation in heavy snow.

• 한국산업보건학회지
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• 제20권2호
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• pp.88-93
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• 2010

To confirm and quantify asbestos fibers released from the asbestos-cement slate roofs due to weathering, three houses, selected based on the year of built - 60's, 70, and 80's, were investigated. All of them were located in the downtown of Seoul. Rain or snow-melt water was collected from the roof in a 3.5 liter plastic bottle. A known amount of collected water was filtered on the 37 mm membrane filter, ashed in a muffle furnace, and subsequently treated with HCl to remove organic material. The treated remaining was refiltered on a 25mm membrane filter for PLM and PCM analyses. The NIOSH 7400 method was utilized for PCM counting. In addition, SEM/EDX was used to confirm the asbestos types. The results of this study showed that chrysotile fibers were confirmed by PLM in all samples analyzed. A significant amount of asbestos fibers were found in the water samples. The ranges of asbestos fibers counted from the samples collected in the 60's, 70's, and 80's were; 10,406.3~55,575.6 f/L, 5,218.8~38,126.2 f/L, and 2,906.3~7,798.6 f/L, respectively. As anticipated, concentrations of asbestos fibers increased with time of installment of the roofing material. We conclude that weathering can be a significant factor on the release of asbestos fibers from the asbestos cement products. Since asbestos fibers released into environment can be a source of significant health hazard, countermeasures, such as replacement, removal, and encapsulation of weathered asbestos slate, should be initiated immediately.

• 한국산학기술학회논문지
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• 제17권4호
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• pp.264-272
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• 2016

본 연구에서는 국내 비도심 지역의 교통사고 저감을 위해 충청권을 대상으로 기존연구에서 수행된 관련 문헌 검토, 교통사고분석시스템 자료를 통한 요인분석 및 군집분석과 설문조사, 충청권 교통사고 특성을 분석하여 실정에 맞는 3가지 교통안전기술을 제안한 바에 이어, 실제 적용 가능한 교통안전시설물의 상세 설계 및 테스트베드 적용, 만족도 조사 및 기술개선에 초점을 맞추고 추가 연구를 수행하였다. 제안된 3가지 기술은 충청권 교통안전수준의 향상을 위한 교통안전시설물로서, 보행자 건널목 인식등, 교통약자 노견용 인식 등, 농기계 운행 안전 LED전광판이다. 각각의 기술은 기존 교통안전시설물의 비도심 지역에 적용시 발생가능한 빛 공해 및 제설작업 문제점을 보완하고, 태양광기반 자생기술로서 농촌지역의 교통안전에 기여할 것으로 판단된다.

• 한국항행학회논문지
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• 제27권1호
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• pp.63-70
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• 2023

본 연구는 선박 추진 축계의 무선 센서 시스템(WSS) 응용을 위한 용량성 무선 전력 전송(C-WPT) 시스템을 제시한다. 커플링 커패시터 양쪽의 단일 Q 팩터 및 회로에서 무효 전력제거를 위해 양면 LCLC 컨버터 및 변압기 토폴로지가샤프트에서 WSS용 회전식 C-WPT 시스템을 구동하도록 설계되었습니다. 170pF의 용량을 갖는 병렬 연결된 평행판 회전 커패시터가 설회전축의 C-WPT 시스템용으로 설계 및 구현된다. 실험 결과 C-WPT 시스템은 3mm 거리 및 1 MHz 작동 주파수에서 7.8 W 출력 전력으로 66.67 %의 전송 효율을 달성했다. 따라서 제작된 C-WPT 시스템은 회전축의 WSS에 전원을 공급할 수 있음을 증명하였다.

• 한국지형학회지
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• 제18권3호
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• pp.121-129
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• 2011

기후지형학 관점에서 몽골의 지형환경은 대륙성 한랭-건조 지형의 대표성을 지니고 있다. 본 연구는 이곳 스텝지역의 지형환경 특색을 파악하려는 것이다. 이곳에서의 지표과정은 매우 역동적이다. 기온교차가 심한 한랭 환경임과 동시에 제한된 양이지만 동계강설로 공급되는 수분은 이곳을 서릿발작용에 의한 기계적 풍화가 강하게 진전되는 지역으로 만들고 있다. 이렇게 생성된 풍화물들은 하계 폭우시의 지표수와 봄철 바람작용에 의해 침식·제거되고 있다. 몽골 스텝지역의 사면들은 토층발달이 미약한 박토상태인데도 모든 사면에서 평활하게 펼쳐져 있다. 이는 풍화와 풍화물 침식이 균형을 이루는 모습이다. 몽골의 지형환경은 서릿발작용에 의한 풍화, 지표수와 바람에 의한 침식, 이들 모두가 활발하면서도 서로 균형을 이룬다는 특색을 지니고 있다.

• 산업경영시스템학회지
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• 제46권spc호
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• pp.61-67
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• 2023

Special equipment used for snow removal is only used in the winter and must be moved into storage during non-winter seasons. However, when moving heavy equipment using a forklift within a limited space, safety accidents may occur due to deformation and damage due to the worker's limited visibility and excessive loading of heavy objects. In this study, the scissors boom of the developed heavy load transporter was conducted in two cases: link structural analysis and position-based structural analysis. In detail, the link structural analysis covers four cases of stress and safety factor according to material and thickness to optimize the specifications of the material selected during development, and the structural analysis according to position covers two cases before and after the lift, when maximum stress concentration is achieved. Safety was evaluated through finite element analysis. As a result of the study, when manufacturing a scissors boom type heavy load transporter that can withstand a load of 10 tons, the link showed safety at SS400 4.5mm or higher, and reinforcement is needed in the upper and lower structures, so it is judged to be useful in applying materials according to the load.

• 한국도로학회논문집
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• 제10권3호
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• pp.149-158
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• 2008

본 연구는 도로 상의 눈이나 얼음의 제거에 사용되는 융빙제와 부식방지제 및 저부식성 제설제 그리고 이들의 조합에 대한 성능 및 구조물에 미치는 영향에 대하여 분석하였다. 동결융해 후 무게손실률은 저부식성 제설제가 융빙제와 부식방지제 및 이들의 조합보다 적게 나타났고, 상대동탄성계수 감소는 물, 저부식성 제설제 및 NaCl+JF-1004를 제외하고 융빙제와 부식방지제 및 이들의 조합물들은 동결융해 150사이클 이후에 급격히 떨어지는 것으로 나타났다. 또한 동결융해 후 콘크리트는 물을 제외하고 상당히 심한 표면 손상을 나타냈다. 융빙 효과는 융빙제와 저부식성 제설제 및 부식방지제의 조합하여 사용할 때가 이들 개별적으로 사용될 때보다 우수한 것으로 나타났고, 저부식성 제설제 및 부식방지제의 단독 사용은 초기 융빙 성능 뿐 아니라 지속성도 현저히 낮아 현장 적용에는 문제가 있는 것으로 판단된다. 강재부식시험의 pH는 저부식성 제설제와 NaCl+JF-1004의 pH는 알칼리성을 띠는 반면에 이외의 나머지에서는 중성에서 산성으로 변화해 가고 있는 것으로 나타났고, 염화나트륨의 조합물이 다른 수용액보다 상당히 빠르게 무게감량이 나타나 강재 부식속도가 빠르게 진행되는 것으로 나타났다. 이상으로부터 도로상의 눈이나 얼음의 제거를 위하여 융빙제의 조합물을 사용 시 최대한 도로 포장 및 교량에 손상이 적게 미치는 조성물에 대한 신중한 선택하여 사용해야 할 것이다.