• 생물환경조절학회지
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• 제17권1호
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• pp.60-65
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• 2008

돌나물의 노지 가을삽식을 위하여, 줄기의 삽수 부위(상부, 중부, 하부) 및 삽식 방법(점파, 조파 산파)에 따른 월동전후 생육특성을 조사하였다. 삽수부위에 따른 삽목후 40일째의 월동전 생육은 상부 삽수에서 초장, 근장, 줄기수, 지경수, 지상부 생체중 및 건물중 등에서 유의하게 높았으며, 월동후 개화전(May 10th) 생육은 개체당 줄기수, $m^2$당 지상부 생체중 및 건물중에서 하부 삽수보다 유의한 증가를 보였다. 삽식 방법에 따른 삽목후 40일째의 월동전 생육은 점파($10{\times}10cm$)가 조파나 산파보다 양호하였고, $m^2$당 지상부 생체중 및 건물중도 점파>산파>조파 순으로 높았다. 월동후 생육(May 10th)은 개체당 줄기수, $m^2$당 생체중 및 건물중에서 점파가 조파보다 유의하게 증가하였다. 돌나물의 가을 노지 삽식은 줄기 상부의 삽수를 이용하는 것이 월동 전후 생육 및 수량성에 유리하였으며, 삽식방법은 점파에서의 수량성이 가장 양호하였으나, 생력화를 위해서는 월동후 생체중에서 점파와 유의한 차이를 보이지 않은 혼파방법이 바람직할 것으로 기대되었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.268-271
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• 2007

A sandwich tube is a structured material that has two inner and outer circular tubes and light material between them. In this paper, a sandwich tube with a pyramidal truss core is introduced. Fabrication method and example made by brazing are shown. The behavior of the sandwich tube under lateral loading is predicted by analytical and numerical method. Comparative study between the sandwich and the monocoque tube is performed at a point of view such as strength and weight saving. As a result, proposed tube is appropriate for application to lightweight structural material

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권3호
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• pp.277-282
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• 2005

This paper describes a step-down AC voltage regulator using an AC chopper and auxiliary transformer, which is a series connected to the main input. The detail design of the AC regulator, logic and PWM pattern of the AC chopper is described and the three-phase AC regulator using two single­phase AC choppers with a three transformer configuration is proposed for three-phase application. The proposed three-phase system has the advantages of lower system cost due to reduced switch number and gate driver circuit as well as advantages of decreased size and weight because it uses a series compensated scheme. The proposed AC regulator has many benefits such as fast voltage control, high efficiency and simple control logic. Experimental results indicate that it can be used as a step-down AC voltage regulator for power saving purposes very efficiently.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.347-348
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• 2002

The numbers of synthetic greases have been developed with synthetic oils because of their excellent performance factors including thermal/oxidation stability, low-temperature fluidity and plastic compatibility. Long life under high-temperature condition and excellent low-temperature fluidity are required to serve as grease for bearings of engine room electrical component. As many plastics are used in place of metals for the purpose of weight saving, synthetic hydrocarbon grease is in use to avoid adverse effect on plastics. Other various special synthetic greases are also in use depending on specific requirements like conductivity and vacuum condition.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2644-2649
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• 2011

The purpose of this study is to propose the modular design of hybrid lightweight carbody structures made of sandwich composites and aluminum extrusion. The sandwich composites were used for secondary structures to minimize the weight of carbody, and the aluminum extrusions were applied to primary structures to improve the stiffness of carbody and manufacturability. Key requirements were defined for the modular design of hybrid carbody, and the applied parts of sandwich composites were determined through the topology optimization analysis. Consequently, feasibility of enhancing mass saving and maintainability in modular hybrid carbody design were presented, comparing with the carbody structures made of aluminum extrusion or sandwich composites only.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.469-474
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• 2002

Recently fiber sheets are used for strengthening the damaged concrete structures due to its many advantages such as its durability, non-corrosive nature, low weight, ease of application, cost saving, control of crack propagation, strength to thickness ratio, high tensile strength, serviceability and aesthetic. However, the lack of analytical procedures for predicting the nominal moment capacity by the fiber sheet reinforcement leads to difficulties in the effective process of decisions of the factors in the strengthening procedure. In this work, flexural strengthening effects by fiber sheets bonded on soffit and web of the member are theoretically studied for the reinforced concrete T beam. The analytical solutions are compared with experimental results of several references to verify the proposed approach.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 봄 학술발표회논문집
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• pp.35-42
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• 2000

Among the various models proposed for the description of semi-rigid connection behavior, Kinney's fixity facto. (=f) definition is adopted. If one follows this definition, f=1.0 signifies a completely fixed connection and f=0.0, the frictionless hinge. Kim's new slope-deflection equations based on the Kinney's fixity factors are the principal idea of this paper. Proposed finite element program also includes the effect of axial shortening of column, which is neglected in the stress analysis of frame leg conventional slope-deflection method. For the economic design, especially for the saving of beam weight in the high-rise office buildings or apartment houses, the proposed method can be applied.

• 동력기계공학회지
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• 제8권3호
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• pp.23-29
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• 2004

In this paper, a finite element formulation using dynamic-explicit time integration scheme is used for numerical analysis of Hydro-forming processes. The lumping scheme is employed for the diagonal mass matrix and dynamic explicit formulation. Hydro-forming process for auto-body panel forming is analyzed by using dynamic-explicit finite element method. Further, the simulated results of the Hydro-forming processes are shown and discussed. Its application is being increased especially in the automotive industrial area for the cost reduction, weight saving, and improvement of strength.

• 한국정밀공학회지
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• 제22권3호
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• pp.78-85
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• 2005

The static implicit finite element method is applied effectively to analyze total roof panel stamping processes, which include the forming stage. complicated and abnormal Large size roof panel was analyzed by using commercial program called AutoForm. Analysis results examining possibility and validity of the AutoForm software and the factor study are presented. Further, the simulated results for the total roof panel stamping processes are shown and discussed. Its application is being increased especially in the automotive industrial area for the cost reduction, weight saving, and improvement of strength.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 춘계학술대회 논문집
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• pp.54-58
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• 2001

In recent years, hydroforming technology has been one of the most important technology in automotive industry in the points of weight saving, cost reduction and qualify improvement. However, compared with traditional metal forming technology, hydroforming has much fewer information in experience and empirical knowledge. But we don't have my sufficient time and money to produce hydroforming products using real blank directly Therefore Simulation is essential in hydrofonrung technology development. In this paper, we simulate the side member as the tubular hydroforming technology. The manufacturing process of side member' consists of pre_bending, pre_forming, and hydroforming of a thin tube. Variables such as internal pressure, end feeding, and tool geometry are optimized to improve the forming safety. And we simulate side member according to several lubricant conditions. from those simulations, we find that strain distributions can be reduced well by internal pressure and end feeding control, and lubrication is the most important thing in hydroforming process.