• 동력기계공학회지
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• 제14권6호
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• pp.35-40
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• 2010

This article deals with the numerical analysis results of stiffness of diaphragm spring used in the clutch of a manual transmission. In order to investigate the relationship of the force and displacement in a diaphragm spring, we have established a numerical model of diaphragm spring using a well-known analytic model of Belleville spring and a cantilever beam model for the finger part of diaphragm spring. Using the stress and strain relations of Belleville spring and cantilever beam, we propose the analytic equation of motion of diaphragm spring for the use of a clutch automated actuator in an automated manual transmission. The proposed analytic model represents the typical dynamic characteristics of diaphragm spring along with the release bearing travel. And it is characterized in a closed-form equation, therefore it can be used for the further study of development of actuator and control law of clutch automating mechanism.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1060-1062
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• 1996

This paper presents a discrete adaptive observer for MIMO system of an IM model in DQ reference model. The IM model in the stationary frame is discretized and it is transformed into the canonical observer form. The unknown parameter is choosen as rotor speed. The adaptive law for parameter adjustment is obtained as a set of recursive equations which are derived by utilizing an exponentially weighted normalized least-square method. The proposed adaptive observer converges rapidly and is also shown to track time-varying plant parameter quickly. Its effectiveness has been demonstrated by computer simulation.

• 한국수자원학회논문집
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• 제30권5호
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• pp.495-501
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• 1997

펌프동력이 기지 값으로 주어져 있을 때, 유량이나 관경을 산정하는 경우 기존의 방법으로는 상당한 반복과정을 거쳐야 된다. 이에 유동훈과 강찬수(1996)는 균일조도 동력경사관인 경우 유량인 관경을 양해법으로 산정하는 식을 개발한 바 있다. 마찰계수 산정을 위한 지수함수식의 이용은 본 양해법 산정식의 개발을 가능하게 하였다. 유동훈(1995a)은 상용관이나 복합면을 가진 관의 마찰계수 산정을 위한 마찰계수 평균법을 제시한 바 있다. 그와 같은 접근방법으로 본고는 마찰계수 평균법을 상용관 마찰계수 산정식에 적용하여 동력경사 상용관의 유량이나 관경을 양해법으로 구할 수 있는 산정식을 개발하였다.

• 무역상무연구
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• 제13권
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• pp.131-149
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• 2000

In connection with international commercial arbitration the need to seek interim relief is generally recognized. Interim reliefs address the requirements of a party for immediate and temporary protection of rights or property pending a decision on the merits by the arbitral tribunal. The most common forms of interim relief are attachments and injunctions. If the arbitral tribunal has not yet been appointed, an application for interim relief must usually be addressed to the local courts at the place of commercial arbitration. If the arbitral tribunal has been appointed, the application for interim relief is first made to the arbitral tribunal. Interim relief by the arbitral tribunal is in the form of a direction to the parties. Since the arbitral tribunal has no enforcement power, it may be necessary to have a arbitral tribunal's direction confirmed by a local court which can enforce its order. The New York Convention does not provide for interim reliefs. The question is whether Article II(3) of the New York Convention that the court "shall, at the request of one of the parties, refer the parties to arbitration" denies jurisdiction to courts to grant interim reliefs in international commercial arbitration. Some cases have indicated that the U. S. court have no power to grant interim relief. Other cases have indicated that the U. S. courts do have the power to grant interim relief. It is unlikely that a U. S. court will order interim relief in relation to an commercial arbitration in a foreign country. Article 26 of the UNCITRAL Arbitration Rules provides with respect to interim measures of protection. Section 1 of Article 26 of UNCITRAL Arbitration Rules provides that the arbitral tribunal may take any interim measures it deems necessary in respect of the subject matter of the dispute, including measures for the conservation of the goods forming the subject matter in dispute. This article gives the arbitral tribunal the broadest authority, not limited to safeguarding property. Article 17 of the UNCITRAL Model Law on International Commercial Arbitration provides that the arbitral tribunal may order any party to take such interim measure of protection as the arbitral tribunal may consider necessary in respect of the subject matter of the dispute. It may be noted that the article does not deal with enforcement of such measures. The International Chamber of Commerce Rules of Conciliation and Arbitration do not expressly empower the arbitral tribunal to grant interim reliefs. However, Article 8.5 of the ICC Rules of Conciliation and Arbitration provides that the parties shall be at liberty to apply to any competent judicial authority for interim measures. In conclusion, the power of the arbitral tribunal to provide interim reliefs is generally recognized in the arbitration rules of arbitral institutions. However, the arbitral tribunal's authority is limited by its lack of enforcement mechanisms. It is generally recognized that the local courts have power to grant interim reliefs in aid of an commercial arbitration. However, local courts are reluctant to grant interim reliefs if that decision requires an adjudication of issues within the special competence of the arbitral tribunal.

• 소성∙가공
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• 제14권7호
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• pp.607-612
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• 2005

In this paper, warm deep drawing process with local heating and cooling technique was attempted to improve the formability of AZ31 magnesium alloy which is impossibly to form by conventional methods at room temperature by finite element method and experiment. For FE analysis, in first model with considering heat transfer, both die and blankholder were heated to 573K while the punch was kept at room temperature by cooling water. Also distribution of thickness and von Mises stress at room temperature and 498k for warm deep drawing were compared by FEM. Uniaxial tension tests at elevated temperature were done in order to obtain the temperature dependence of material constant under temperature of $293K\~573K$ and cross head velocity of $5\~500mm/min$. The phenomenological model for warm deep drawing process in this work was based on the hardening law and power law strain rate dependency. Deep drawing experiment were conducted at temperatures of room temperature, 373K, 423K, 473K, 498K, 523K, and 573K for the blank and deep drawing tools(holder and die) and at a punch speed of 10mm/min.

• 대한기계학회논문집A
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• 제24권5호
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• pp.1331-1342
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• 2000

In power generation systems a variety of structural components typically operate at high temperature and pressure. Therefore a life assessment methodology accounting for gradual creep fracture is increasingly needed for these components. The most critical defects in such structure are generally found in the form of semi-elliptical surface cracks in the welded tubular joints. Therefore the analysis of a semi-elliptical surface crack in a plate or a shell is an important problem in engineering fracture mechanics. On this background, via shell/line-spring finite element analyses of such surface cracks in the welded T and L joints under various loadings, we investigate J-integral along the crack front We first develop T and L joints auto mesh generation program providing ABAQUS input file composed of shell/line-spring finite elements. We then further develop a T and L joints life assessment program based on the experimental creep crack growth law and auto mesh generation program in a graphical user interface format Finally the remaining life of T and L joints for various analytical parameters are assessed using the developed life assessment program.

• 문화기술의 융합
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• 제6권1호
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• pp.327-334
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• 2020

조선 후기 3대 명필로 지칭될 만큼 독자적 서풍을 창안한 창암(蒼巖) 이삼만(李三晩)(1770~1845)은 '법고(法古)'를 중시하였는데, 한위대(漢魏代) 서예를 근본으로 하고, 동국진체(東國眞體)를 완성한 원교(圓嶠) 이광사(李匡師)를 마음의 스승으로 삼아 수련하였다. 만년에는 올바른 필법 전수를 위해 『창암서결(蒼巖書訣)』을 저술하여 보편적 서예의 기본원리와 자신의 서예관을 피력하였다. 창암(蒼巖)이 지향하는 서체는 해서(楷書) 근골(筋骨)의 확립을 통한 초서(草書)로 완결된다. 이를 위해 한위(漢魏)의 서체를 전범(典範)으로 제안하였는데, 온후간원(穩厚簡遠)한 한위근골(漢魏筋骨)은 무위자연적(無爲自然的) 무법(無法)의 경지를 보여준다. 이로 보아 창암(蒼巖) 서예론의 핵심이자 궁극적 지향점은 '자연(自然)'임을 알 수 있다. 이는 법의 극치에 이르러 다시 무법(無法)으로 돌아가는 것으로, 여기에서 음양(陰陽)이 생성되고 형(形)·세(勢)·기(氣)가 부드러움을 도모하면 기괴(奇怪)함이 생겨난다고 보았던 것이다. 한편, 고법(古法)에 얽매이지 않고 우졸(愚拙)한 자연천성(自然天成)을 발현하면 장법과 포치가 일운무적(逸韻無跡)한 득필천연(得筆天然)을 이룬다고 강조하였다. 우리는 이 연구에서 그의 서체가 자연을 예술로 승화하면서, 조선 고유의 서예미를 끊임없이 접목·시도하였음을 살펴볼 수 있다. 그리하여 근골이 풍부하고 생명력과 역동감이 넘치는 형세를 이룬 일운무적(逸韻無跡)을 체화(體化)하였고, 득필천연(得筆天然)한 극공(極工)의 심미경지를 이루어 독창적인 '행운유수체(行雲流水體)'로 구현하였고 마침내 호남지방에 동국진체(東國眞體)의 서풍과 서예정신을 더욱 창달시켰다.

• Steel and Composite Structures
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• 제20권1호
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• pp.205-225
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• 2016

In this study the finite element method is utilized to predict the deflection and vibration characteristics of rectangular plates made of saturated porous functionally graded materials (PFGM) within the framework of the third order shear deformation plate theory. Material properties of PFGM plate are supposed to vary continuously along the thickness direction according to the power-law form and the porous plate is assumed of the form where pores are saturated with fluid. Various edge conditions of the plate are analyzed. The governing equations of motion are derived through energy method, using calculus of variations while the finite element model is derived based on the constitutive equation of the porous material. According to the numerical results, it is revealed that the proposed modeling and finite element approach can provide accurate deflection and frequency results of the PFGM plates as compared to the previously published results in literature. The detailed mathematical derivations are presented and numerical investigations are performed while the emphasis is placed on investigating the effect of the several parameters such as porosity volume fraction, material distribution profile, mode number and boundary conditions on the natural frequencies and deflection of the PFGM plates in detail. It is explicitly shown that the deflection and vibration behaviour of porous FGM plates are significantly influenced by these effects. Numerical results are presented to serve as benchmarks for future analyses of FGM plates with porosity phases.

• Steel and Composite Structures
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• 제28권1호
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• pp.13-24
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• 2018

A size-dependent novel hyperbolic shear deformation theory of simply supported functionally graded beams is presented in the frame work of the non-local strain gradient theory, in which the stress accounts for only the nonlocal strain gradients stress field. The thickness stretching effect (${\varepsilon}_z{\neq}0$) is also considered here. Elastic coefficients and length scale parameter are assumed to vary in the thickness direction of functionally graded beams according to power-law form. The governing equations are derived using the Hamilton principle. The closed-form solutions for exact critical buckling loads of nonlocal strain gradient functionally graded beams are obtained using Navier's method. The derived results are compared with those of strain gradient theory.

• 한국식품과학회지
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• 제22권6호
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• pp.646-650
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• 1990

마늘의 장기저장 및 새로운 향신료 개발의 일환으로 마늘을 착즙한 후 농축시켜 저장 및 중간 향신 소재화 하고자 하였으며, 그 연구의 일환으로 마늘 착즙 및 그 농축액의 rheological properties에 대해 연구하였다. 마늘 착즙 및 농축액의 흐름거동은 고형물 농도$50^{\circ}Brix$까지는 power-law model에 대체로 잘 적용되었으나 $60^{\circ}Brix$ 이상의 농도에서는 항복응력을 고려한 Herschel-Bulkley model이 더 적절한 것으로 여겨졌으며, 의가소성 유체(pseudoplastic fluid)의 특성을 나타내었다. 고형물 농도 $32{\sim}60^{\circ}Brix$, 온도 $15{\sim}65^{\circ}C$의 범위에서 유동지수는 $0.6130{\sim}0.9937$로 온도가 상승할 수록 증가하였으며, 이 때 점조도지수는 $3.1886{\sim}0.0041Pa\;s^n$였다. 마늘 착즙의 겉보기점도는 전단속도의 증가에 따라 직선적으로 감소하였으며 유동에 따른 활성화에너지는 $11,216{\sim}23,195\;kJ/kg\;mol$이었다.