• 대한기계학회논문집
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• 제11권1호
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• pp.132-144
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• 1987

본 논문에서는 Isida의 이론해석 방법을 참고로 하여 유한한한 폭을 갖는 두 께가 변화하는 판재에서의 응력확대계수를 2차원 이론해석한 것이다.

• 한국작물학회지
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• 제47권1호
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• pp.36-41
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• 2002

Two rice varieties, 'Oochikara' with large grain and 'Hwayeongbyeo' and their progenies (F$_1$, F$_2$, B$_1$ and B$_2$) were tested to understand gene action of morphological traits of rice grain and their relationships. The evaluated traits were 1,000-grain weight, grain length, width, thickness, length-width ratio and chalkiness of brown rice. Correlation between grain weight and chalkiness was highly significant in the all progenies, and grain length were not associated with width and thickness in an F$_2$ population. Scaling test and jonit scaling test revealed that inheritance of grain traits were fitted to additive-dominance model without epistasis. Additive effects for the traits were much greater than the dominance effects.

• 한국수자원학회논문집
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• 제49권7호
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• pp.635-644
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• 2016

본 연구에서는 2차원 수치모형을 이용하여 개수로 분류부에서 분류수로 폭과 유량비 변화에 따른 흐름특성을 파악하였다. 2차류 영향을 고려한 분류부 수치모의시 흐름분포를 실험결과에 더 정확하고 안정하게 모의가능하다. 분류수로내 통수능을 감소시키는 흐름분리구역과 2차류의 상호 작용에 의한 흐름정체 효과는 분류유량비를 감소시킨다. 분류부 상류 유입유량과 유속이 감소할수록 수로폭 변화에 따른 분류유량비 변화가 더 크다. 동일 하류단 경계조건에서 분류수로 폭을 감소시킬 때, 본류 하류부 프루우드 수-분류유량비 관계식의 변화율은 -2.4843~-2.6675로 유사하게 나타난다. 동일 분류유량비 조건에서 분류수로 폭이 감소할수록 수축계수는 증가하고, 흐름분리구역의 폭은 감소한다. 분류수로 폭을 증가시킬 경우 분류부 상류 유입유량이 적을수록, 그리고 분류부 상류 유입량을 증가시킬 경우 분류수로 폭이 좁을수록 흐름분리구역 폭 감소율이 더 크다. 동일 상류 유입유량 조건에서 분류수로 폭이 감소할수록 분류유량비, 흐름분리구역의 길이와 폭은 감소한다.

• 대한토목학회논문집
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• 제30권3A호
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• pp.241-256
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• 2010

본 연구에서는 변장비 70에 가까운 도전적인 현수교 단면을 개발하는데 목적을 두고 있다. 이를 위하여 먼저 강박스 현수교의 제원을 수집 분석하였다. 그 결과를 보면 강박스 현수교에서 경간장과 형상변수(교폭, 형고, 변장비, 고폭비)는 상관관계가 낮았고 고유진동수와 형상변수의 상관관계도 낮은 것으로 나타났으며, 상관관계가 높은 경간장과 고유진동수 관계는 신뢰구간별 추정식을 제시하였다. 그리고 교폭, 진동수비, 질량, 질량관성모멘트, 수직 및 비틈 고유진동수 변화에 따른 플러터 풍속의 민감도 분석을 실시하였는데, 타 변수보다 비틈 고유진동수가 플러터 풍속에 미치는 영향이 가장 큰 것으로 나타났다. 주경간장 1111 m인 현수교의 내풍 단면을 개발하기 위하여 최소 단면폭과 형고를 제약조건으로 하여 총 30개의 단면에 대한 풍동실험을 실시하고, 이로부터 한계풍속 기준을 충분히 만족하는 단면을 찾았다. 그리고 다중모드 플러터 해석으로 개발한 단면의 내풍안정성을 검증하였다. 본 연구에서 제시한 세장 단면은 향후 장대 현수교 설계시 활용할 수 있을 것으로 판단된다.

• 한국농공학회지
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• 제14권2호
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• pp.2603-2609
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• 1972

농경지 조건이 트랙터 작업 능율에 어떻게 영향을 미치는가에 대해 연구한 결과 제1차 시험에서 다음과 같은 결과를 얻었다. (1) a당 경운 소요시간이 가장 큰 것이 $10{\times}30m$구로서 본 시험에서 길이가 가장 짧은 시험포이며 가장 작은 것이 $20{\times}120m$ 구로서 길이가 가장 긴 시험포이다. 따라서 나비와 길이의 비가 1:6인 경우에 가장 유리하였다. (2) 잔경부분을 최소한도로 감소시키려고는 했으나 제6구에 있어서는 7.52%에 달하여 가장 높은 비율을 나타내었고 제1구에서 3.44%로 나타나 가장 낮은 비율로 나타났다. 이로써 토지이용율을 장방형구획일수록 높음을 알 수 있었다. (3) 그러나 장방형이라 하더라도 나비가 좁을 때는 오히려 이용율이 낮았으며 적어도 나비는 20m 이상이어야 토지이용율은 노ㅠ음을 알 수 있었다. (4) Tractor를 이용해서 경운작업을 할 때에는 그 잔경부분에 대한 처리방법에 대해서 계획을 세우지 않으면 토지이용율면에서나 소요경운시가면서 큰 손실을 면지못함을 알 수 있었다.

• 한국치위생학회지
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• 제12권2호
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• pp.345-353
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• 2012

Objectives : The author has studied about correlation of gingival exposure upon smiling and oral facial status that reduce facial aesthetic. Methods : The subjects in this study are 91 female vulunteers who were in aged $21.4{\pm}1.89$ in Suwon. Objectives should be normal oral and facial status without the prosthodontic, orthodontic appliance or conqenital missing tooth, and agree to be examined the oral status and impression taking. 1.Measure the length of gingival exposure upon smiling. 2.Measure of the size on central incisor. 3.Measure of Facial. SPSS(SPSS 10.0 for windows, SPSS Inc, Chicago, USA) was utilized for calculating the correlation coefficient between gingival exposure upon smiling and facial status. Regression analysis was calculated in order to predict the R square for gingival exposure upon smiling. Results : 1.Correlation coefficient between the gingival exposure and length of maxillary central incisor was calculated as reversed correlation(r=-.302, p<0.01), and between the gingival exposure and the ratio of the length of central incisor/width of central incisor was revealed as reversed correlation(r=-.250, p<0.05) on smiling. 2.There was correlation between the gingival exposure and the facial height(r=.351, p<0.01), the lower facial height(r=.454, p<0.01) and the upper lip height(r=.274, p<0.01) upon smiling. 3.There was correlation between the gingival exposure and the ratio of the facial height/facial width(r=.358, p<0.05), the ratio of the upper facial height/facial width(r=.214, p<0.05), and the ratio of the lower facial height/facial height(r=.383, p<0.01) upon smiling. 4.The equation of the regression analysis for gingival exposure upon smiling could be estimated as gingival exposure upon smiling=-5.139+.279${\times}$lower facial height-.615${\times}$maxillary central incisal length-.05${\times}$nasolabial angle. Conclusions : Considering these results, it recommended that treatment planning should be designed in consideration of such factors as the length of maxillary central incisor, facial height, upper lip height and lower facial height, in order to promote the easthetic problems of face on smiling.

• Journal of the Korean Wood Science and Technology
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• 제23권4호
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• pp.46-53
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• 1995

The anatomy of Korean diffuse-porous woods, 36 families, 75 genera, 145 species, 215 specimens was described and analyzed. Sixteen wood anatomical characters, habit and phenology factors were determined by simple correlation and principal component analysis. Strong positive correlations were found between vessel element length and fiber length, ray width and ray height, simple pits of fiber wall and paratracheal parenchyma distribution. The results of principal component analysis (PCA) disclose the primitive characteristics and the direction of xylem evolution of Korean diffuse-porous woods. The xylem evolution scenario for Korean dicotyledonous woods is considered to be developed in the direction of decreasing trends of vessel frequency, vessel element length, and length/diameter(L/D) ratio of vessel element but increasing trends of vessel diameter, fiber length/vessel element length(F/V) ratio, libriform wood fibers, simple perforation, and homogeneous ray composition. Increase of vessel diameter and decrease of vessel frequency seem to be related to the improvement of conductive efficiency, and increase of the vessel element length and occurrence of scalariform perforation in vessel element may be related to enhanced of conductive safety. Also the libriform wood fibers and ray features appear to have relationship with mechanical support and nutrient metabolism, respectively.

• 한국산업보건학회지
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• 제3권2호
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• pp.204-212
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• 1993

This study was conducted to evaluate ventilation efficiency of 4-stage slot hood by variation of slot width, flow rate, hood size and baffle size. The slot velocity, control velocity and plenum velocity were related to slot width and the distance between source of contamination and hood. The results obtained from laboratory experiment for local exhaust ventilation systems were as follows ; 1. When slot widths were constant(equally changed) and the velocity was 6-10 m/s, the slot velocity from 1st slot to 4th slot gradually decreased. As the slot width-to-slot length ratio(WLR) decreased, the slot velocity of each stage increased. But if WLR value was less than 0.04, the slot velocity decreased. 2. When slot velocity exceeded 10 m/s with constant slot widths, the slot velocity of each stage was uniform. 3. When the slot velocity was uniform within 10 m/s and the first slot width was 14-20 mm, the slot width ratio between 1st slot and each of three other slots were 1, 1.25, 1.5 and 3.0, respectively. 4. The slot and plenum velocity were uniform when exhaust flow rate changed from 14 to $19m^3/min$ and there were no hood splitter vanes. 5. When the slot velocity at each stage was uniform, the control velocity at site 30 cm away from hood No.2 increased from 0.15-0.30 to 0.25-0.45 m/s and the control distance from 20 to 30 cm(about 1.5 times).

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.202-208
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• 2003

In this study, a time domain analysis is presented for investigation on the buffeting response of cable-stayed bridge during both erection and completion stages. The main span length and width of deck are 520 m and 15.1m, each. Since the ratio of span over width is 34.44, aerodynamic stability of the bridge during erection is expected to dominate the safety of the bridge in construction stage. Several conclusions regarding different construction stages and temporary wind cables are obtained.

• 복합신소재구조학회 논문집
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• 제6권3호
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• pp.26-31
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• 2015

The domestic and foreign specifications presented the effective width based on flange length to width ratio only. The existing paper on the effective width grasped of the effect of span, load type and cross-section properties, but localized steel bridges. Recently, The studies are going on in progress for the application of fiber reinforced composite material in construction field. Therefore, it is required to optimum design that have a good grasp the deformation characteristic of the displacements and stresses distribution and predict variation of the effective width for serviceability loading. This research addresses the effective width of all composite material box girder bridges using the finite element method. The characteristics of the effective width of composite structures may vary according to several causes, e.g., change of fibers, aspect, etc. Parametric studies were conducted to determine the effective width on the stress elastic analysis of all composite materials box bridges, with interesting observations. The various results through numerical analysis will present an important document for construct all composite material bridges.