• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.572-577
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• 1997

This present paper describes a mathematical model of profile elliptical gears, and this model is based on the concepts of envelop theory and conjugate geometry between the blank and the straight-sided rack cutter. The geometric model of the rack cutter includes working regions generating involute curves andd fillets for trocoidal curves, and furthermore the addendum modified coeff,is considered for avoiding undercutting. The addendum modified coeff, is changed linearly along with pitch curves and must be the must be the same absolute value at both major semi-axis and minor semi-axis. If undercutting is at all pronounced, the undercut tooth not only are weakened in strength, but lose a small portion of the involute adjacent to the base circle, then this loss of involute may ncause a serios reduction in the length of contact. A very effective method of avoiding undercutting is to use the so-called profile shifted gearing. Non-undercutting conditon is examined with the change of eccentricity and addendum modefied coeff. in elliptical gears and then the minimum number of tooth is proposed not to gernerate undercutting phenomenon.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.6
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• pp.1070-1081
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• 1989

본 논문의 목적은 일반적인 곡면을 갖는 냉간단조 공정을 컴퓨터 시뮬레이션 을 통해 해석하고자 강소성 유한요소법의 프로그램을 개발하고, 이를 축대칭 및 평면 변형 단조성형에 적용하고자 한다. 축대칭 문제로는 산업적으로 이용이 많은 치차 블랭크(gear blank) 형태의 예제를 선택하였고 평면변형으 경우 정밀 단조품의 하나인 터어빈 블레이드(turbine blade)를 평면변형 문제로 보아 해석하였다. 한편 심한 변형을 하는 후방압출과 같은 문제의 수렴성을 향상시키고 공정을 계속적으로 해석하 기 위하여 격자 재구성기법을 도입함으로서 냉간단조 문제의 일반적인 해석을 하도록 한다.

• Journal of Power System Engineering
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• v.15 no.5
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• pp.67-71
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• 2011

Fine blanking is a specialized form of blanking where there is no fracture zone when shearing. This is achieved by compressing the whole part and then an upper and lower punch extract the blank. This allows the process to hold very tight tolerances, and perhaps eliminate secondary operations. In the present study, tensile test and numerical simulation has been performed to investigate distribution of deformation and stress of car seat recliner. The commercial ABAQUS/Explicit software was applied for analyzing the stress and strain of the recliner. In analysis, three lock gear has reached the maximum moment on rotational degree of 2.27. This is more than two times than maximum moment of same size recliner, and can be used safely. Therefore, these can use as criterion of actual structural design.

• Journal of the Korean Society of Costume
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• v.4
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• pp.39-59
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• 1981

This article briefly researched the Picture of Welcoming the Governor of Pyongan Province painted by Kim Hong-do, penname Danwon(1745-1818?). The Picture was composed of three parts and its historical and pictorial back-ground were reviewed firstly. And later the dress and its ornament appearing on the Picture were studied. In the historical viewpoint of dress and its ornament, the Picture shown all sorts of dress from lower class maids and servants to higher officials-dignatories and governor, and dealt with nearly all dresses. In order to support and to make better understand the dresses of that age, some Korean literary works of the same period depicting the dress and its ornament were also selected. This article dealt with the dress and its ornament. especially that of 18th century of the Yi Dynasty, and comparatively studied for our folk painting with literary works. Also the picture enabled to make this study was an important data of our old dress and its ornament. This painting was considered as one of our cultural treasures. Several conclusions drawn out from this study as followings: 1) In male and female dress of lower class people; male dress was consist of trouser and coat, and coat, and over the coat SOCHANGYI were used. Female dress was basically consist of skirt and these were white color of their favourite. Mainly simple color was used for clothing and its dress style were CHAKSOO-HYONG (narrow sleeve style) which convenient for a work. 2) Yangban's dress was consist of trouser, coat and over the coat, usually DOPO(over-coat) were used and some case JICKRYONGPO (a sort of over-coat) or CHANGYI were also used. These were GWANGSOO-HYONG (wide sleeve style) of inconvenient for a work. 3) In head-gear, there was no difference of the higher and the lower. They usually used HEUC-KRIP (black Korean hat). The OCKJUNGJA, GONJAKMI (peacock tail), HOSOO (tiger beard), and YOUNGJA (chin strip) were used according to officials ranks as head-gear's oraments. 4) Local petty officials used ordinary dress and CHUPRI (warn-dress) were also used by them, and military officials used war-dress of tight sleeve. 5) The belting of over-coat are different in color according to official grade. The higher grade wore red-wide belt, but generally black narrow belt for ordinary officials. 6) All KISAING girl wore SAMHYEOIJANG upper coat. And their head ornament were black KARIMA for grown KISAING. SAYANG hair for DONGKI or maiden KISAING and BINYEO (an ornamental rod of women's hair) were inserted into the hair of rear down part of head. The water carring maid wore BANHYEOIJANG upper coat and no KARIMA were on head and their coat were gloomy color. Above mentioned are several conclusions, and there migh be a false or erroneous explanations of 18th century dress and its ornament, however I considered they were data for blank period of quite unknown.