• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.439-442
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• 2003

This study presents a new computational model to analyze the grain deformation in a polycrystalline aggregate in a discrete manner and based directly in the underlying physical micro-mechanisms. As a result, specific characteristics have to be considered for the numerical analysis. The grains and grain boundary elements are introduced to model individual grains and grain boundary facets, respectively, to consider the size effects in the micro forming. The constitutive description of the grain elements accounts for the rigid-plastic and the grain boundary elements for elastic relationships. The capability of the proposed approach is demonstrated through application of grain element and grain boundary element in the micro forming.

• 기술사
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• 제19권2호
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• pp.34-42
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• 1986

These brief studies and reports of the use of exposed aggrigate precast concrete in practice are combined with a description of some notable co-ordination such as shop drawing, manufacturing and erection in the field construction. Above mentioned exposed aggrigate P. C. means architectural P. C. which was used to the VOTRAKON site in Riyadh, Saudi Arabia. Fabricated P. C. on the site without autoclaving and steam curing plant had been successfully carried out on this project-core building, conference room and others. The project designed by HOPE/VTN international INC. which is located in San Diego, California U.S.A. stands for vocational training and related support facilities contract. We had to submit shop drawings showing complete information for fabrication and installation of P. C. unit reinforcement. Also we should be indicated member dimension and cross section, location size and type of necessary for erection. We can delineate the following characteristic results. One of the most important things how to handle exposed aggrigate P.C. unit as specified was quality assurance and co-ordination for shop drawing, manufacturing and erection.

• 한국주거학회논문집
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• 제14권3호
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• pp.127-136
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• 2003

The purpose of this study is to establish concept about a plan direction of preschooler's library, and provide a design type of preschooler's library. As a result, the following findings were obtained: 1) For the preschooler's reading area, it should be segregated between schooler and preschooler. Because there is a difference between a library use action and a development characteristic, it needs to be segregated to avoid conflict using library for both of those groups. 2) The space composition of preschooler's library stands up, and of a tube considers a traffic line of a user according to the function and systematizes a child, and to cause an interest of preschoolers. 3) Furnitures and equipment of preschooler's library must arrange in consideration of human body size of a user in a tube.

• 대한기계학회논문집A
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• 제28권9호
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• pp.1255-1261
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• 2004

A variational approximation procedure is introduced to study the contact stresses between a representative asperity and a feature generally happening in superfinishing processes such as FAM. After a description of the model under consideration is presented, a system of governing equation for the model is derived fullowed by the assumptions made in order to make progress in model development. Final computation is made to evaluate contact stresses on an elastic asperity tip in small scale in size and a computer simulation is performed for detailed surface profile variations on a representative feature. Numerical results are presented along with a discussion of the conclusions that can be drawn from this analysis.

• 지질공학
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• 제8권2호
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• pp.189-203
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• 1998

상업용 Packer를 이용하여 시추공내에서 암반의 변형율 측정 할 수 있는 Dilatometer방법을 개발하였다. 직경 0.5인치, AX, BX, NX 및 HX크기의 시추 공에서 사용 할 수 있는Packer-dilatometer를 개발하여 현장에서 암반 변형율을 측정하였다. 본 방법은 Packer에 의하여 시추 공 벽에 압력을 가하여 이때 발생된 암반의 변형을 Packer에 주입된 주입수의 양으로 측정하는 방법이다. 본 논문에서는 이방법의 이론적 해석, 장비, 시험방법 및 순서, Calibration 정수 산정을 위한 장비 및 방법, Contact pressure의 측정 및 이를 이용한 현장조사 결과에 대한 연구 내용을 기술 하였다.

• Steel and Composite Structures
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• 제26권4호
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• pp.421-437
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• 2018

Free vibration analysis of a three-layered microbeam including an elastic micro-core and two piezo-magnetic face-sheets resting on Pasternak's foundation are studied in this paper. Strain gradient theory is used for size-dependent modeling of microbeam. In addition, three-unknown shear and normal deformations theory is employed for description of displacement field. Hamilton's principle is used for derivation of the governing equations of motion in electro-magneto-mechanical loads. Three micro-length-scale parameters based on strain gradient theory are employed for prediction of vibrational characteristics of structure in micro-scale. The results show that increase of three micro-length-scale parameters leads to significant increase of three natural frequencies especially for increase of second micro-length-scale parameter. This result is according to this fact that stiffness of a micro-scale structure is increased with increase of micro-length-scale parameters.

• International Journal of Automotive Technology
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• 제5권3호
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• pp.145-153
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• 2004

Potential fuel economy improvements and environmental legislation have renewed interest in Gasoline Direct Injection (GDI) engines. Computational models of fuel injection and mixing processes pre-ignition are being developed for engine optimisation. These highly transient thermofluid models require verification against temporally and spatially resolved data-sets. The authors have previously established the capability of PDA to provide suitable temporally and spatially resolved spray characteristics such as mean droplet size, velocity components and qualitative mass distribution. This paper utilises this data-set to assess the predictive capability of a numerical model for GDI spray prediction. After a brief description of the two-phase model and discretisation sensitivity, the influence of initial spray conditions is discussed. A minimum of 5 initial global spray characteristics are required to model the downstream spray characteristics adequately under isothermal, atmospheric conditions. Verification of predicted transient spray characteristics such as the hollow-cone, cone collapse, head vortex, stratification and penetration are discussed, and further improvements to modelling GDI sprays proposed.

• Interaction and multiscale mechanics
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• 제4권2호
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• pp.123-137
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• 2011

We review a series of crack problems arising in the general deformations of a linearly elastic solid (Mode-I, Mode-II and Mode-III crack) and, perhaps more significantly, when the contribution of surface effects are taken into account. The surface mechanics are incorporated using the continuum based surface/interface model of Gurtin and Murdoch. We show that the deformations of an elastic solid containing a single crack can be decoupled into in-plane (Mode-I and Mode-II crack) and anti-plane (Mode-III crack) parts, even when the surface mechanics is introduced. In particular, it is shown that, in contrast to classical fracture mechanics (where surface effects are neglected), the incorporation of surface elasticity leads to the more accurate description of a finite stress at the crack tip. In addition, the corresponding stress fields exhibit strong dependency on the size of crack.

• Journal of Chest Surgery
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• 제10권1호
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• pp.143-147
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• 1977

Atrial septal defect is the most common of the congenital heart disease in the adult. Since the first description of atrial septal defect by Rokitansky in 1857, this anomaly has been studied by many workers in past one century. In 1953, Lewis had first corrected the atrial septal defect under direct vision with deep hypothermia, and Gibbon [1954] had first done the atrial septal defect under direct vision with extracorporeal circulation. In our college [May 2’ 1977], we have first repaired the A.S.D. under direct vision with artificial heart-lung machine and, the defect was 4x5cm in size which was closed by Dacron patch. This patient was 12 year old girl who is well now. [postoperative 13 days]

• Animal Systematics, Evolution and Diversity
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• 제28권3호
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• pp.208-211
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• 2012

Caminus jejuensis n. sp was collected from depth of 20 m at Geomeunyeo, Seogwipo, Jejudo Island by a SCUBA diving from April 2004 to December 2008. This new species is similar to C. chinensis from China in the composition of spicules except for the spherasters and they differ in spicule size and growth form. This species has longer orthotriaenes and spherules, smaller sterrasters and oxyasters than those of C. chinensis. This species also has many spherasters in choanosome, but C. chinensis lacks. Morever, the new species is a massive shape with wrinkles, whereas C. chinensis is a club shape with smooth surface. Description and figures of the new species are provided.