• 한국철도학회논문집
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• 제7권1호
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• pp.49-54
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• 2004

Particularly derailing freight wagon, which are loaded with dangerous chemicals, has large damages on humans and environment. In this paper the dynamic characteristic of the laminated leaf spring under extreme situation, for example derailment, is examined. The leaf spring has a static hysteresis. Not only the friction value, but also the spring rate are influenced by this hysteresis characteristic. Because of the static hysteresis of the leaf spring the spring rate must be used in normal operation depending upon the loading and the kind of the excitation with the up to 10-fold value of the static spring rate. Some characteristics of the leaf spring can be treated like well-known viscous damping, but fer special situation (preload and/or excitation) particular calculation are necessary.

• 한국정밀공학회지
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• 제12권5호
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• pp.88-97
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• 1995

The leaf spring is used in the suspension of most buses and trucks due to its compactness, which reduces the shock-force and the vibration from the road, and increases passenger comfortability and carlife. Of the various kinds of leaf springs, the leaf spring without eyes can be found easily in the heavy duty truck, and has different characteristics to the leaf spring with eyes in the case of large free camber. Because of radius change, the leaf without eyes slips on the supports, which makes the deflection. The difference is due to this deflection. In this paper, we show the general method of characteristic analysis, for example, Pandan method, can be no more applicable to these springs. Thus considering the geometry deflection by slip, we have developed the equation of the characteristic of the leaf spring without eyes and prove the effectiveness of this equation by experiment. From the result, at large camber the slip deflection is large and as camber smaller, this is smaller. At the camber behind some value, the effect of slip no longer influence to the characteristic of leaf springs.

• 한국자동차공학회논문집
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• 제6권6호
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• pp.1-6
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• 1998

A leaf spring plays an important role in a passenger bus. Since characteristic of a leaf spring has a hysteresis behaviour, modeling technique for a leaf spring is an important issue for passenger bus analysis. In this paper, modeling technique for a leaf spring is presented. First, non-linear FEM model of a leaf spring is constructed then it is used to make an approximated model to be used in dynamic analysis. The modeling procedure is ex-plained in step by step approach. Then, this model is applied to dynamic analysis of a mini-bus with flexible body and non-linear dynamic force element. The results are compared with test data.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.69-70
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• 2008

• Journal of Plant Biology
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• 제17권2호
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• pp.99-105
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• 1974

Author has studied and reported on taxonomy of Korean sedges, using gross morphology, anatomy and epidermal patterns of the leaf blades(1969, 1971, 1973, 1974). This paper is the 6th report of epidermal patterns of leaf blade on sedges and includes 5 genera, Eriophorum, Fuirena, Kobresia, Rhynchospora and Scirpus. The author proposed to find epidermal patterns of leaf blades as an important taxonomic characteristic of sedges classification. The result of this study, the elements of leaf epidermis, subsidal cells, silica body, cell wall of long cell, prickles, and arrangement of the elements are considered to be significant characteristics for the identification and classification of sedge.

• 대한기계학회논문집
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• 제10권3호
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• pp.399-407
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• 1986

본 연구에서는 공기역학 탄성베어링의 설계에 필요한 기본이론에 대하여 고찰 하고 그의 신빙성을 그러한 베어링에 지지된 고속회전축의 진등측정을 통하여 검토하 고저 한다. 탄성베어링의 한 예로써 여러 개의 탄성박판이 겹쳐 저어널을 지지하는 겹판베어링(

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.620-623
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• 2000

The leaf spring is generally used effectively in load supporting because it has tension-diffused function in comparison with other springs. Nowadays the leaf spring is used widely in the suspensions of automobile and trains. The stiffness and the damping characteristics of the leaf spring being essential for the performance of vehicles, the exact evaluation is required. Various approximate formula are normally used for the leaf spring design. however, accuracy and trust are decreased because the contact and frictional characteristics between leaf plates are generally neglected. In this paper, nonlinear stiffness matrix of the leaf spring is solved by contact-element applying FEM for considering the contact and frictional characteristics between leaf plates. The results of proposed FE model are compared with test data.

• 한국자원식물학회지
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• 제18권3호
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• pp.367-373
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• 2005

본 연구의 목적은 쑥속 자원에 대한 생육인자간 상관성 구명과 생육인자 모형 개발을 위해 수행하였다. 생육인자의 특성에서 초장 초폭, 엽병장, 엽록소량은 더위지기, 엽장은 넓은잎외잎쑥, 엽폭은 쑥, 줄기직경은 뺑쑥, 엾두께는 더위지기, 쑥, 산쑥, 넓은 잎외잎쑥, 그늘쑥이 가장 높은 값을 나타냈다. 생육인자 간 상관분석 결과 사철쑥은 엽폭과 줄기직경, 산쑥은 초장과 초폭, 넓은잎외잎쑥은 초장과 엽폭, 나머지 종들은 엽장과 엽폭이 높은 상관성을 보였다. 생육인자 모형 분석 결과 사철쑥은 약 $79.4\%$, 쑥은 약 $91.7\%$, 산쑥은 약 $70.3\%$, 더위지기는 약 $49.0\%$, 넓은잎외잎쑥은 약 $72.5\%$, 그늘쑥은 약 $75.0\%$, 뺑쑥은 약 $60.4\%$, 덤불쑥은 약 $54.4\%$의 설명력을 나타내었다.

• 복식
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• 제45권
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• pp.161-178
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• 1999

In contemporary fashion metal have used which is as the material with a sufficient potentiality of expression which is displayed by an unique characteristic involved only in metal. In this paper metal expressed in contemporary fashion is researched. The first thing the formative characteristic of metal is researched under the consideration of type technique and color of metal used in contemporary fashion. Metals such as gold silver bronze aluminum thin lead and iron are usually used in fashion and those metals are used in various types such a thread fabric board leaf a and cable. Those types of metal as above are applied to the clothing by the techniques of weaving embroidering metal leaf printing or moulding which gives the formative characteristic to the clothing. In color metal has an effect on the colors of surroundings by its smooth and unique luster and its effect of reflection and produces the visual formative characteristic through the effects of contrast. The esthetic will of metal expressed in modern fashion is researched in this study under the facts studied as above. first metal expresses the future oriented esthetic Second metal has the characteristic of attracting the attention Third metal is used as valid techniques to express the artistic formation for clothing escaping from the idea that the clothing is only for wearing. Finally metal is used as an anti-cultural tool of fighting against the existing order or spirit.

• Nuclear Engineering and Technology
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• 제30권4호
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• pp.287-297
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• 1998

The elastic stiffness formula of leaf type holddown spring(HDS) assembly is verified by comparing the values of elastic stiffness with the characteristic test results of the HDS's specimens. The comparisons show that the derived elastic stiffness formula is useful in reliably estimating the elastic stiffness of leaf type HDS assembly. The elastic stiffness sensitivity of leaf type HDS assembly is analyzed using the formula and its gradient vectors obtained from the mid-point formula. As a result of sensitivity analysis, the elastic stiffness sensitivity with respect to each design variable is quantified and design variables of large sensitivity are identified. Among the design variables, leaf thickness is identified as the most sensitive design variable to the elastic stiffness of leaf type HDS assembly. In addition, the elastic stiffness sensitivity, with respect to design variable, is in power-law type correlation to the base thickness of the leaf.