• 소성∙가공
• /
• 제9권6호
• /
• pp.574-581
• /
• 2000

A vertically-walled auto-body part is one of the most difficult stamping parts because of angle change, wall curl, and twisting of the blank after springback as well as fracture and wrinkle. In this study, computational simulations of the vertically-walled auto-body part are carried out focusing on angle change, wall curl, and twisting after springback. Binderwrap blank shape is used in forming analysis for precise initial contacts between punch and blank. An adaptive mesh method is used in springback analysis for precise calculation of bending moments. In springback analysis, the differences of 2 and 3 dimensional analysis are compared and the effects of blank holdig force and friction coefficient are evaluated. In order to verify the validity of simulation results, they are compared with measured ones. The predicted thickness distribution and formed shape are agreed well with those of the measurement. The Predicted springback amount is less than that of the measurement.

• 한국CDE학회논문집
• /
• 제10권6호
• /
• pp.421-431
• /
• 2005

This paper introduces a new approach for saving build time of hybrid rapid prototyping by decomposing a part into minimum number of layers. In the hybrid rapid prototyping, a part of a complicated shape is realized by adding layers of a simpler shape, each of which is obtained by machining a sheet of constant thickness from its top and bottom surfaces. Thus it is desired to decompose a given part into the minimum number of layers while guaranteeing each layer to be fabricated from the given sheets using a 3-axis milling machine. To satisfy these requirements, a concave edge-based algorithm is proposed to decompose a part into layers by considering the tool accessibility, the total number of layers, and the allowable sheet thickness.

• 복식
• /
• 제40권
• /
• pp.95-107
• /
• 1998

The purpose of this research paper is to offer basic data for cloth design which is intended to apply appropriate shape and catacity to cloth. Followings are the analyzed result of investigation which was conducted to figure out the character of middle aged from 35 to 59 years old-women body especially in lower half of their body. 177 women took part in this investigation. 1. As a result of analyzed characters for middle aged women body shape, taking a side view of body, there are great variance in thickness coefficient which indicates the size of body. 2. According to a comparison result of early middle aged women body shape with late middle aged women body shape, the value in height items get shorter otherwise the value in thickness items get longer getting older. It means late middle aged women are relatively fat. 3. For the analysis of women body especially in lower half, 8 factors were used. They are as followings. Factor 1. Side thickness of lower half. Factor 2. Width of lower half. Factor 3. Height of lower half Factor 4. Droop of underbelly Factor 5. Salient rate of buttocks. Factor 6. Length of buttocks. Factor 7. Salient rate of underbelly. Factor 8. Droop of buttocks 4. Lower half shapes of middle aged women were divided into three groups and the character of each group are as followings. 〈Group 1〉65.0% of women who took part in this investigation have this type of body shape. They have long value in height items and thickness items. 〈Group 2〉16.4% of women who take part in this investigation were belonged to this group. The value in height items were not so different from group 1 but the thickness value are shorter than group 1. Women of group 2 have slime body shape. 〈Group 3〉18.6% of women were belonged to group 3. They show the shortest value in height items otherwise the longest value in thickness items. Therefore they are the smallest and the fattest group in this investigation.

• 대한기계학회논문집A
• /
• 제35권6호
• /
• pp.591-598
• /
• 2011

현재 철도차량이 분기기 통과 시에 횡압의 변화가 최소화하는 설계가 요구되고 있다. 따라서 차량이 분기기를 통과하는 경우에 분기기에 작용하는 횡압 및 탈선계수를 예측하기 위하여 차량과 분기기간의 상호작용에 따른 동역학 해석을 수행하여야 한다. 본 연구에서는 분기기 단면 형상 변화가 차량의 주행안전성에 미치는 영향을 살펴보기 위해 포인트부, 크로싱부의 단면 형상 변화에 따른 주행안전성 해석을 수행하였다. F10/F12 분기기를 대상으로 포인트부 텅레일의 길이, 크로싱부 노즈레일의 높이를 변경시켜 주행안전성 해석을 수행하였다.

• 한국해안·해양공학회논문집
• /
• 제36권4호
• /
• pp.138-148
• /
• 2024

다중공진 파력발전체는 파랑의 공진현상을 복합적으로 이용하여 실해역의 평상파 내습시에도 파랑을 증폭시켜 효율적인 발전이 가능하다. 공진에 의해 파랑이 증폭될수록 다중공진 파력발전체의 발전 효율이 증가하며, 발전 효율이 최대가 될 수 있도록 공진부의 형상 최적화가 필요하다. 다중공진 파력 발전체는 항만 공진부와 수로 공진부에서 파랑을 증폭시키며, 본 연구에서는 수로 공진부의 길이, 위치 등 다양한 조건에서 CFD 수치실험을 수행하여 조건 별 상관성을 분석하고 수로 공진부의 최적 형상을 도출하였다.

• 한국패류학회지
• /
• 제27권3호
• /
• pp.273-282
• /
• 2011

The ultrastructural characteristics of germ cells during spermatogenesis and mature sperm morphology in male Pinctada martensii were investigated by transmission electron microscope observation. The morphologies of the sperm nucleus and the acrosome of this species are the oval shape and cone shape, respectively. Spermatozoa are approximately $47-50{\mu}m$ in length including a sperm nucleus (about $1.24{\mu}m$ in length), an acrosome (about $0.60{\mu}m$ in length), and tail flagellum (about $45-47{\mu}m$). The axoneme of the sperm tail shows a 9+2 structure. In P. martensii in Pteriidae, a special substructure showing a thick and wide triangular shape which is composed of electron-dense opaque material (occupied about 50% of all, the upper part of the acrosomal vesicle), appeared in the upper region (part) of the acrosomal vesicle, while the lower region (part) of the acrosomal vesicle is composed of electron-lucent material. Thus, this special structure, which exist in the upper part of the acrosomal vesicle in P. martensii, is somewhat different from those of other subacrosomal vesicle in other families in subacrosomal vesicles. Therefore, we assume that the existence of a special substructure showing a thick and wide triangular shape in the acrosomal vesicle of the spermatozoon can be used as a key characteristic for identification of P. martensii or other species in Pteriidae in subclass Pteriomorphia. The number of mitochondria in the midpiece of the sperm of this species are five (exceptionally sometimes four), as one of common characteristics appear the same number of mitochondria in the same families of superfamilyies. This species in Pteriidae does not contain the axial rod and satellite fibres which appear in the species in Ostreidae in subclass Pteriomorphia. These characteristics can be used for the taxonomic analysis of the family or superfamily levels as a systematic key or tools.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
• /
• pp.1078-1083
• /
• 1992

Extracting the process planning information from the CAD data is the key issue in integrated CAD/CAM system. In this paper, we develop algorithms for extracting the shape and setup configuration for NC machining of prismatic parts. In determining the workpart shape, the minimum-enclosing condept is applied so that the material waste is minimized. To minimize the number of setups, feature based algorithm is developed considrint the part shape, tool shape, and tool approach direction. The validity and effectiveness of the developed algorithms were tested by computer simulations.

• 청정기술
• /
• 제20권3호
• /
• pp.226-231
• /
• 2014

본 연구는 미세 몰드 기술을 이용하여 산세기 자극에 따라 모양이 변화하는 야누스 입자를 제조하는 방법에 관한 것이다. 야누스 입자는 산세기(pH) 응답형 단량체인 acrylic acid (AA)를 사용하여 친수성 부분을 제조하고, trimethylolpropane triacylate (TMPTA)를 사용하여 소수성 부분을 제조하였다. 제조된 야누스 입자는 산세기 변화에 따라서 친수성 부분의 팽윤이 유도되며 결과적으로 자극 응답성을 가짐을 증명 하였다. 자극 응답성 정도는 산세기의 범위 또는 AA의 조성을 다양화 함으로써 제어가 가능하다. 더 나아가 야누스 입자의 양쪽 부분이 반대 전하를 띄는 특성을 부여하기 위해 AA와 2-(dimethylamino)ethyl methacrylate (DAEMA)를 사용하여 양극성 야누스 입자를 제조하였다. 양극성 야누스 입자는 동일한 산세기 조건에서 서로 다른 팽윤율을 갖게 되며 비대칭적 형상을 띄게 된다. 결론적으로, 본 연구에서는 야누스 입자의 친수성 부분에 산세기 응답형 단량체를 사용함으로써, 산세기 자극에 의해 가역적으로 모양 변형이 가능한 야누스 입자를 제조하였다. 본 연구를 통해 제조된 자극 응답형 야누스 입자는 향후 바이오 센서나 검출 기구 등에 활용 될 것으로 기대한다.

• 복식문화연구
• /
• 제14권5호
• /
• pp.840-849
• /
• 2006

Breast volume has been approximately estimated under the assumption that the shape of breast is a corn. However, women's breast is more like a bulged bag in reality. In this paper, three methods of breast volume estimation were compared to find out the more accurate method. The shape of the breast is assumed as a hemisphere in the first estimation method and a corn in the second one. In the third method, arc along the cross sectional shape of breast was utilized in the calculation. Comparisons among the methods were made using the actual 3D volume measurement of thirty seven women's breast. As results, the third method was the best one for the normal breast type, especially for the lower part of the breast ($R^2=0.74$) which is the crucial design parameter of the brassiere. Assumption of the shape of breast as a corn was reasonably acceptable when the breast is sagged. It was expected that when women wore brassiere, the accuracy of the third method would increase more, since the shape of breast becomes more symmetrical.

• 패션비즈니스
• /
• 제11권5호
• /
• pp.124-135
• /
• 2007

To understand tendency of body shapes of Chinese women who reside in Beijing and Shanghai for improving the match of exported clothes to China, this categorizes the bodies by extracting the elements of the objects and understanding body promotion. To categorize the subject by not size factor but form factor, data were compared and analyzed mainly with index based on measurement of the body. This selected specimen as 1381 of Chinese women from 19 to 50 selected in random sampling in Shanghai and Beijing from 23th, June to 7th August in 2004. 1. Chinese women is generally separated in 7.09 parts and upper body including waist shapes round. 2. The elements indicating the women's physical properties are obesity, the size of upper part, front shape, side shape, shoulder and back shape, perpendicular size and lower part length, body shape. 3. The Chinese are categorized by three factors. Normal shape which is not both fat and skinny, records the highest in the ranking.