• 대한기계학회논문집A
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• 제28권1호
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• pp.55-62
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• 2004

Although the previous researches evaluated the fatigue behavior of glass fiber/epoxy laminates using the traditional fracture mechanism, their researches were not sufficient to do it: the damage zone of glass fiber/epoxy laminates was occurred at the delamination zone instead of the crack-metallic damages. Thus, previous researches were not applicable to the fatigue behavior of glass fiber/epoxy laminates. The major purpose of this study was to evaluate delamination behavior using the relationship between crack length and delamination width in hybrid composite material such as Al/GFRP laminate. The details of investigation were as follows : 1) Relationship between crack length and delamination width, 2) Relationship between delamination aspect ratio and delamination area rate, 3) Variation of delamination growth rate is attendant on delamination shape factors. The test results indicated that the delamination growth rate depends on delamination width delamination aspect ratio and delamination shape factors.

• 한국연초학회지
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• 제6권1호
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• pp.19-24
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• 1984

This study was carried out to find out the variations in Burley 21 variety of Surely tobacco. Jeonjul and nine other selected lines of Burley 21 were evaluated. Plant height and several other characteristics were significantly different among tested lines. Especially, Jangsu-1, the earliest flowered line, flowered 5 to 7 days earlier than other lines and had the smallest length width ratio of the largest leaf. Narrow-leaved type, whose length/width ratio of the largest leaf was above 2, 16, was significantly different in number of leaves and weight per unit leaf area from broad-leaved type whose length/width ratio of the largest leaf being below 1.97. Among tested lines, Jeonju (2) - 2 was the best in major agronomic characteristics, yield and physical properties.

• 한국작물학회지
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• 제52권2호
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• pp.123-128
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• 2007

Demand for high quality rice has always been a major factor in the international rice marketing. In the present study, doubled haploid (DH) population derived from anther culture of a Tongil/japonica hybrid was used for genetic analysis of rice grain quality. The average values of DH lines for grain weight, grain length and the ratio of grain length to width were near the mid-parent value. More than 40% DH lines showed transgressive segregation for grain weight, length, amylose and lipid content, but less than 10% DH lines observed on ratio of length to width and grain thickness were transgressive segregation. Correlation analysis between appearance qualities and physicochemical characters indicated that grain width and grain thickness both significantly and negatively correlated to protein and lipid content. A highly significant negative correlation between protein content and amylose content was observed.

• ALGAE
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• 제18권4호
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• pp.239-253
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• 2003

The morphotaxonomic characters of the genus Spirogyra were investigated to clarify their taxonomic category and the variation range among species on the basis of comparative morphological and numerical analyses by unialgal cultures and field samples collected from various freshwater habitats in Korea. 25 characters selected on morphological feature of the species were examined on 568 individuals for morphological comparisons and numerical analyses. Width, length and their length/width ratio of vegetative cell, shape of septum, chloroplast number, maximum width, width, length and their length/width ratio of female gametangium, length of male gametangium, size and shape of zygospore, and cell wall ornamentation of the spore showed a comparatively high vector in principal component analysis. In cluster analysis, 15 taxa analysed were divided into 8 major groups by the average taxonomic distance 1.0 level. Considering the morphology and numerical analysis, Spirogyra crassoidea could not be recognized as an independent species, therefore it was treated as a variety of S. ellipsospora. S. koreana (nom. invalidum), recognized as a new taxon, is under the investigation for its clear taxonomic category.

• 한국지진공학회논문집
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• 제19권2호
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• pp.75-83
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• 2015

The purpose of this study is to improve the previous damage evaluation model for RC members which is proposed by Igarashi[1] in 2010.The previous model was not confirmed by enough data of damage such as, residual crack length, width and area for exfoliation of concrete, etc. In addition, validation of the model is still insufficient. Therefore, experiment of a real-scale RC structure and experiment of RC columns using the high-strength concrete were conducted to gather the data of damage in RC members. The investigation has been conducted gathering the data not only additional experiments data but also existing data for modification of damage evaluation model. It has been investigated on changing damage in RC due to axial force ratio, shear reinforcement and shear span ratio. As a result, several problems were founded in the previous model, such as, hinge length($l_p$), spacing of flexural crack($S_{av,f}$), total width of flexural cracks regulated by maximum width of flexural crack($n_f$) and total width of shear cracks regulated by maximum width of shear crack($n_s$). New model is proposed and evaluated the damage properly.

• The Journal of Advanced Prosthodontics
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• 제4권1호
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• pp.13-17
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• 2012

PURPOSE. We aimed to identify a more esthetic width-to-length ratio by analyzing maxillary central incisor of Korean adult population. Information regarding tooth ratio in the Korean population may be useful to clinicians when restoring anterior teeth. MATERIALS AND METHODS. A total of 40 men and 40 women were included in this study. The NON-MEDIA group included 40 non-celebrities, who were healthy and 25 to 39 years old, with normal dentofacial appearance. The MEDIA group consisted of 40 celebrities selected only on the basis of their soft-tissue facial appearance. The facial photographs of 40 celebrities were collected from the Internet websites. The width and length of the maxillary central incisor were measured using Adobe $Photoshop^{(R)}$ 7.0, a software for analysis, measurement and edition of photographs. Data were analyzed statistically using the Independent t-test at 5% statistical significance level. RESULTS. The mean ratio for the MEDIA group was 0.77, whereas that of the NON-MEDIA group was 0.88. The difference between the two groups was statistically significant. No significant gender differences were found in the width-to-length ratio in MEDIA group. In NON-MEDIA group, however, there were significant differences between female and male. CONCLUSION. After analyzing maxillary anterior teeth of Korean adults, our results were in accordance with the general Western standards of esthetics. A dentist restoring the natural look and beauty of teeth will have to consider those standards.

• 한국육종학회지
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• 제40권2호
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• pp.143-152
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• 2008

1913년부터 2000년까지 국내에서 육성된 70품종에 대한 초형형질에 관련된 주경, 분지 및 엽형질의 특성을 파악하여 다수성 콩 품종개발의 기초자료로 이용코자 하였다. 1. 초형형질의 변이는 주경과 분지관련형질의 12개 형질 중에서 초형폭, 분지장 및 초형폭/장 비율이 컸으며, 엽관련 8개형질 중에서는 엽병각, 엽장폭비 및 엽건물중이 컸다. 2. 용도별로 초형폭/장 비율은 밥밑콩이 장류 및 두부용콩과 나물콩에 비하여 높았고 장류 및 두부용콩과 나물콩은 큰 차이가 없었다.총분지장/주경장 비율은 나물콩과 밥밑콩이 높았고 장류 및 두부용콩이 낮았다. 3. 주경과 분지형질은 초형폭/장 비율과 총분지장/ 주경장 비율에 의하여 각각 그룹으로 분류되어졌고, 협초폭형이며 주경의존형은 단원콩, 금강콩, 셀비 및 신팔달콩이었고, 협초폭형이며 분지의존형은 소명콩이었다. 광초폭형이면서 주경의존형은 강림, 금강대립 및 진율콩이었으며, 광초폭형이면서 분지의존형은 검정콩 2호이었다. 4. 용도별로 소엽장/폭 비율은 밥밑콩이 작았고 장류 및 두부용콩과 나물콩과는 큰차이가 없었으며, 복엽의 엽면적은 밥밑콩이 가장 컸고 나물콩이 가장 작았다. 엽병장은 나물콩이 작았으며 장류 및 두부용콩과 밥밑콩은 큰 차이가 없었고, 엽병각은 밥밑콩이 가장 컸고 나물콩이 가장 작았다. 5. 엽형태는 엽장폭비와 엽면적에 의하여 각각 4그룹으로 분류 되어졌고, 소엽장폭비가 큰 원엽이면서 엽면적이 큰 대형엽은 부석과 대황콩이었고, 엽장폭비가 극세엽이면서 엽면적이 작은 소형엽은 은하콩과 소호콩이었다. 6. 엽병의 특성은 엽병장과 엽병각에 의하여 각각 3그룹과 4그룹으로 분류 되어졌고, 엽병장이 짧고 엽병각이 작은 품종은 은하콩이었고, 엽병장이 짧고 엽병각이 큰 품종은 알찬콩, 무한콩 및 푸른콩이었으며, 엽병장이 길고 엽병각이 작은 품종은 신팔달콩 2호이었다. 7. 은하콩은 전 시험품종 중에서 엽장폭비가 가장 큰 극세엽이면서 엽면적이 가장 작은 소형엽이었고, 엽병장이 가장 짧으며 엽병각이 가장 작은 품종이었다.

• 한국산림과학회지
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• 제89권5호
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• pp.666-676
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• 2000

굴참나무 천연집단의 형태적 변이(엽형 특성)를 연구하기 위하여 위도, 경도, 해발고 및 지리적 특성을 고려하여 19개 집단을 선발하였다. 각 집단별로 30개체를 대상으로 개체목당 수관 1/3 하단부에서 60개의 엽을 고르게 채집하여 엽신장, 최대엽폭, 엽맥수 및 엽병장을 조사한 후 그 값을 이용하여 엽신장/최대엽폭, 엽신장/엽병장, 상1/3폭/최대엽폭, 상1/3폭/하1/3폭 및 엽병장/엽맥수에 대한 형상비를 계산하여 엽형 특성에 대한 변이를 조사한 결과는 다음과 같다. 1. 엽신장/최대엽폭, 엽신장/엽병장, 엽병장/엽맥수, 상1/3폭/최대엽목, 상1/3폭/하1/3폭, 엽병장 및 엽맥수에 대한 변이는 집단간 및 집단내의 개체간에 고도의 유의적인 차이를 보였다. 특히, 분산기여도는 집단간보다 집단내의 개체간에 큰 것으로 나타나, 굴참나무의 연구는 집단보다 개체에 의한 연구가 바람직할 것으로 보여진다. 2. 엽형특성에 대한 주성분 분석은 첫 두 주성분까지의 적재 가여율이 80.5%로 굴참나무 엽형특성 분류에 중요한 정보를 주는 요인이었다. 각 인자별 기여도에 있어서는 제1주성분에서 엽병장/엽맥수 및 엽병장, 제2주성분에서 상1/3폭/최대엽폭, 상1/3폭/하1/3폭 및 엽맥수 인자가 높은 기여도를 나타냈다. 3. 위도, 경도 및 해발고에 따른 엽형특성에 대한 지리적 변이는 위도에 있어 엽신장/최대엽폭 및 엽신장/엽병장에 대해서는 정의 상관을 나타내었으며, 나머지 특성(엽병장/엽맥수, 상1/3폭/최대엽목, 상1/3폭/하1/3폭, 엽병장 및 엽맥수)들에 대해서는 부의 상관을 나타내었다. 그러나 경도와 해발고는 위도와 반대의 경향을 나타내었다. 4. 군집분석(Complete linkage cluster)한 결과는 거리지수 1.6에서 2개의 그룹 즉, I그룹(Pop. 1, 4, 5 및 13)과 II그룹(Pop. 2, 3, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18 및 19)으로 나뉘었으며, 거리지수 1.3에서는 II그룹이 다시 Pop. 3, 7, 10, 14, 15 및 17의 군집(II-1)과 Pop. 2, 6, 8, 9, 11, 12, 16, 18, 19의 군집(II-2)으로 나뒤어 총 3그룹으로 분리되었다. 대체적으로 이것은 사면의 방향에 대하여 I그룹은 북동면에, II-1그룹은 남동면에, 그리고 II-2그룹은 남서면에 집단이 위치하고 있어 환경조건이나 입지조건의 차이에 의하여 일어난 자연도태의 결과로 집단간 차이를 보이는 것으로 사료된다.

• 한국전산유체공학회지
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• 제20권2호
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• pp.37-45
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• 2015

A parametric study on the shapes of bobsleigh bumpers has been performed to reduce the aerodynamic drag. Effects of geometric parameters, such as leading angle of leading bumper, the ratio of minimum width to maximum width of leading bumper, the ratio of leading bumper length to trailing bumper length, trailing angle of trailing bumper, and the ratio of bumper height to installation location of bumper from the bottom of bobsleigh, on the aerodynamic performance of the bobsleigh were estimated using 3-D Reynolds-averaged Navier-Stokes equations. The turbulence was analyzed using the shear stress turbulence model. Reynolds number based on the hydraulic diameter of the external flow channel was in the range of 150,000~1,000,000. Numerical results for drag coefficient were validated compared to experimental data. Ranges of the five geometric parameters were determined according to the rule of Federation Internationale de Bobsleigh et de Tobaganning. The aerodynamic performance of the bobsleigh sled was most sensitive to the leading angle of leading bumper and the ratio of minimum width to maximum width of leading bumper.

• 대한인간공학회지
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• 제16권2호
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• pp.61-71
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• 1997

In industrial designing of ready-to-wear shoes, one important factor to consider is that the population has diverse fooot shapes as well as foot length. The general shape of a foot could be represented by "foot ratio", i.e. the ratio of width to length. In this study, we measured several dey aspects of young Korean men's foot, and compared the results with their shoe sizes and general foot shapes. To this end, 172 male subjects were categorized according to their shoe size (small, medium, large) or foot ratio (wide, narrow, intermediate). The statistics of this survey indicated that the people with narrow foot shap have significantly greater foot length compared with the one having wide foot shape. Conversely, subjects having wide foot shape manifested significantly greater foot and ankle girth as well as significantly greater foot breadth. However, different foot shape groups showed no significant differences in heel width, heel ankle girth, instep height, and malleolus height. On the other hand, subjects wearing larger shoe size showed significantly larger foot measurements except instep and ankle heights, whereas subjects with shoe sizes 260 and below measured significantly more narrow heel and lateral metatarsal breadths. The deviation between foot length and dress shoe size(length) was greater in groups with wide foot shape and in groups wearing large shoe sizes. The results of this survey indicated that the subjects with wide foot shape apparently choose a size or two larger shoes for them as a compromise for a better breadth fit.eadth fit.