• Journal of the Korean Society of Visualization
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• v.9 no.1
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• pp.17-19
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• 2011

The bubble oscillations play an important role in ultrasonic cleaning processes. In the ultrasonic cleaning of semiconductor wafers, the cleaning process often damages micro/nano scale patterns while removing contaminant particles. However, the understanding of how patterns in semiconductor wafers are damaged during ultrasonic cleaning is far from complete yet. Here, we report the observations of the motion of bubbles that induce solid wall damage under 26 kHz continuous ultrasonic waves. We classified the motions into the four types, i.e. volume motion, shape motion, splitting or jetting motion and chaotic motion. Our experimental results show that bubble oscillations get unstable and nonlinear as the ultrasonic amplitude increases, which may exert a large stress on a solid surface raising the possibility of damaging microstructures.

• Korean Institute of Interior Design Journal
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• no.22
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• pp.110-116
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• 2000

After the industrial revolution, interior of living space have shifted from the spacial structure of existing wall partitions to visually and spacially continuous open space. And these open space can be recognized mostly in the common space of housing architecture of living, dining, and kitchen space composition. In order to understand the characteristics of space and compositional method, the works of Le Corbusier, W. Grupius, and F.L. Wright in their living, dining, and kitchen space design have been analized from the collected materials to make evaluation for the similarities and significance of their space compositional factors. therefore, this study is to analize space composition and design factor of the modern housing space of Living, Dining, and kitchen space variation and character of open space design factor for the practical use as an index of designing contemporary living space.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.317-318
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• 2012

Although installations and usages of gang-form that has advantages of preventing fall disaster, the serious disasters from gang-form occur every year. This research focused on the continuous prevention of disasters in construction of outer wall of apartment working site through step by step safety management worker's checking table. The result is the worker's checking table for safety management in apartment gang-form works, through safety guidelines case studies, interviews with safety management experts and then extracting a check list.

• Journal of the Korea Furniture Society
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• v.22 no.2
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• pp.118-125
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• 2011

These days global warming is the most important problem and the most important factor is high emission of carbon dioxide. The 23% of carbon dioxide emission for building construction must be reduced. Thermal conductivity is the most basic factor that can decrease the energy consumption especially insulation. Therefore, an accurate and continuous thermal conductivity measurement can be a way to save energy. In this paper, there are methods about how to investigate thermal conductivity measurements and comparing two methods which are the Heat Flow Meter 436 and TCi.

• Journal of Plant Biology
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• v.32 no.1
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• pp.11-21
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• 1989

Anatomical and histochemical changes taking place in Piper nigrum berries during their ripening are described. The important observations on the pericarp are the development of sclereids in the exocarp, a continuous band of oil cells in mesocarp and the wall thickening of the endocarpic cells. The mature seed with a single layer of seed coat, representing the innermost tegment layer, encloses abundant perisperm. The endosperm and embryo are situated laterally at the terminal part of the seed. The perisperm is distinguished into an outer protein-rich zone and inner starch-filled zone. Starch and protein are also deposited in the mature pericarpic tissue. Lipid bodies are seem in the form of oil globules in oil cells.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.412-419
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• 2002

This paper presents a parametric study on the behavior of integral abutment PSC beam bridge. An integral abutment bridge is a simple span or multiple span continuous deck type bridge having the deck integral with the abutment wall. The rational structural model and design load combinations accounting for each construction stage are proposed. It can be used for defining the effect of earth pressure and temperature change in the design process including for determining maximum flexural responses. The bending moment at each response location due to the design load combination is investigated according to the change of flexural rigidity of piles and abutment height. The flexural responses of proposed model are computed for the cases of applying the Rankine passive earth pressure and the earth pressure based on the soil-structure interaction respectively, and the results are discussed.

• Corrosion Science and Technology
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• v.7 no.5
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• pp.288-295
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• 2008

The increase use of natural gas as an energy source has been continuous demand for ever-increasing strength in gas transmission pipeline materials in order to achieve safe and economic transportation of natural gas. In particular, linepipe material for sour gas service primarily needs to have crack resistant property. However, applications of sour linepipes are expanding toward deep water or cold region, which require higher toughness and/or heavier wall thickness as well as higher strength. To improve the crack resistance of linepipe steel in sour environment, low alloy steel are produced by controlled rolling subsequently followed by the accelerated cooling process. This paper summarizes the design concepts for controlling crack resistant property low alloy linepipe steels for sour gas service.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.271-276
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• 2001

Conventional clonoscope is semiflexible tube that should be manipulated by operator for inspection and treatment. Therefore, it sometimes causes pain for the patient and even perforation to the wall of colon if a surgeon is not well trained. For safe colonoscopy, self-propelling robots with inchworm locomotion are studied. But, inchworm locomotion has some problems in adaptiveness to the variation of colon diameter. In this paper, we propose novel locomotive mechanism which can move in the colon without any external assistance. It has several cams that have constant phase difference each other and located along the centerline of the mechanism. This mechanism could realize the robotic endoscope which has continuous and smooth thrust force.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.4
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• pp.109-121
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• 2004

A distributed nonlinear mathematical model for investigation of regenerative heat exchangers of both a continuous and periodic operation is described in the paper. The non-iterative numerical integration scheme for conjugate unsteady heat exchange problem of one dimensional flows and two dimensional matrix wall conductivity is developed. Case study of a regenerative heat exchanger with a rotary ceramic matrix is presented. The range of optimum rotation rates of the regenerator providing the greatest calorific efficiency is determined.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1438-1449
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• 1988

An analysis of radiative heat transfer has been conducted on axisymmetric finite cylindrical media. It is assumed that the temperature in the media is uniformly distributed and the boundaries are diffusely emitting and reflecting at a constant temperature. The scattering phase function is represented by the delta-Eddington approximation to account for highly forward scattering by particulates just as in the combustion system. Exact numerical solutions are obtained by Gaussian quadrature method and compared with P-1 and P-3 approximation solutions to verify their engineering application limit. The effects of optical thickness, scattering albedo, wall emissivity and aspect ratio are investigated. The results show that P-3 approximation is found to be in good agreement with the exact solution.