• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1990.10a
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• pp.45-46
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• 1990

In this study, we fabricated Plasma polymerized styrene thin films which used a new capacitive type apparatus. RE Power supply (13.56 MHz) was used and styrene monomer was adopted. After the preparation of thin films the molecular structure of Plasma polymerized styrene films was analyzed by some analyses as IR, FT-IR, Gas chromatography and so on.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.871-876
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• 2001

One-touch fittings are important components that can make a quick and tight connection between pneumatic pipe systems. In this study, the stress analyses with various working pressures on these one-touch fittings are carried out using finite element method. Material properties, to use the stress analyses, are measured by the universal tester and digital Vickers hardness tester. The stress analyses on the circular shell spring forced by various pressures(100, 150, 200, 250kpa) and on the main body due to the fluid-structural interaction are investigated. Results show that the stresses of one-touch fitting are concentrated to supported part of main body and the soundness of a circular shell spring with maximum pressure 250kpa was confirmed.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.160-164
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• 2020

Papenfussiella densa was described as Papenfussiella kuromo f. densa from Japan by Inagaki in 1958. P. densa has been recognized as an endemic and independent species based on the molecular analyses of type material without detailed morphological observations. In this study, Papenfussiella densa is reported as a new record from Dok-do, South Korea, based on morphological and molecular analyses. Papenfussiella densa is mainly characterized as having narrow, branched, slimy, and tomentose thalli with branchlets, partially hollow in the medulla of the middle part. The molecular analyses of the chloroplast rbcL-rbcS DNA sequence of the Papenfussiella densa sample from Korea revealed that it matched that of P. densa from Japan and was nested in the clade of Papenfussiella. There was only a 0.02% gene sequence divergence between the Korean and Japanese samples. We report P. densa as a new record from Korea and add this species to the list of Korean macroalgal flora.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.945-952
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• 1994

In this paper, a mathematical model for a belt driven system is proposed to analyse the vibtation characteristics of the driving units with belts and the free and forced vibration analyses are carried out. The mathematical model for model for the belt-driven system includes belts,pulleys, spindle and bearings. Using the Hamilton principle, the 4 nonlinear governing equations and the 12 nonlinear boundary conditions are derived. To linearize and discretize the nonlinear govering equations and boundary conditions, the perturbation method and Galerkin method are used. Also, the free vibration analyses for the various parameters of the belt driven system, which are belt tension, belt length, material property of belt, belt speed and pulley mass are made. The forced vibration analyses of the system are made and the dynamic responses for the main parmeters are analysed with the belt driven system.

• Journal of the Korea Institute of Building Construction
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• v.10 no.5
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• pp.137-143
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• 2010

This research is a comparative analysis of the surface gloss of concrete depending on the coating material added to the cast, and includes analyses of the surface gloss of specimens made of cement mortar, with and without the addition of superplasticizer. In terms of coating material, the 7th material, which is part of a liquid packaging material, was shown to have the highest gloss, and was followed by the 3rd material, which uses transparent film. As the level of gloss is shown to vary depending on the material used for the coating film, it can be interpreted that the surface gloss can differ depending on surface particles and chemical composition factors. To make a concrete surface smooth, it is more effective to use a coating material with impermeability and a highly dense surface.

• Journal of Mechanical Science and Technology
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• v.20 no.9
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• pp.1428-1435
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• 2006

A slightly curved crack with an eigenstrain is considered. Solutions for a slightly curved crack in a linear isotropic material under asymptotic loading as well as for a slightly curved crack in a linear isotropic material with a concentrated force are obtained from perturbation analyses, which are accurate to the first order of the parameter representing the non-straightness. Stress intensity factors for a slightly curved crack with an eigenstrain are obtained from the perturbation solutions by using a body force analogy. Particular attention is given to the crack path stability under mode I loading. A new parameter of crack path stability is proposed for a crack with an eigenstrain. The path stability of a crack with steady state growth in a transforming material and a ferroelectric material is examined.

• Journal of Ocean Engineering and Technology
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• v.29 no.1
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• pp.70-77
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• 2015

The purpose of this study was to provide fundamental data for an anchor collision simulation of an FCM (flexible concrete mattress). Numerical material models (elastic-perfectly plastic model, Drucker-Prager model, and RHT concrete model) were compared. ANSYS Explicit Dynamics was used for collision analyses. An FE model was used for the anchor, FCM, andreinforcement bars. The results showed that the behavior of the FCM was verydifferent that those ofthe material models. In particular, the effect of the pressure dependent strength was most noticeable among the properties of concrete.

• Structural Engineering and Mechanics
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• v.55 no.3
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• pp.583-603
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• 2015

There are so many applications of perforated pates with various penetration patterns. If they are penetrated regularly, it can be represented by solid plate with equivalent material properties, which has a benefit of finite element modelling and reducing computation time for the analysis. Because the equivalent material properties suggested already are not proper to be applicable for the dynamic analysis, it is necessary to extract the equivalent material properties for the dynamic analysis. Therefore, in this study, the equivalent modulus of elasticity are obtained for the perforated plate with a triangular penetration pattern by comparing the natural frequencies of the perforated plate with those of solid plate, which are represented with respect to the ligament efficacy. Using the equivalent material properties suggested, the modal analyses of the partially perforated rectangular plate with a triangular penetration pattern are performed and its applicability is shown by comparing natural frequencies of perforated and homogeneous solid plates from finite element method and analytical method.

• IE interfaces
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• v.18 no.4
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• pp.431-443
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• 2005

This paper describes a web-based system called DESIGNER for the analysis and design for automated material handling equipment(MHE) applications in manufacturing. DESIGNER models the processes for system integration, economic analysis, performance analysis, and automated storage/retrieval system(AS/RS) design. Based on the information specified by users, the various analysis modules are invoked to meet the needs of the material handling applications. The results of the analyses provide system users with useful data for material handling system design and decision on investment in automated MHE. Example problems are also presented to demonstrate the use of the system.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2634-2645
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• 1993

Dome structures of pressure vessels subjected to internal pressure are usually analyzed by linear elastic theory assuming small deformation. Geometric and material nonlinear behaviors appear in actual dome structures because of large deformation and loads exceeding yield strength. In this paper, linear and nonlinear analyses were performed for various hemispherical and torispherical domes to check the effects of geometric and material nonliearity on the stress and displacement by the finite element method. The effect of the geometric nonlinearity decreased the stress levels a lot for very thin general torispherical domes, which enables more realistic and effective design. The material nonlinear effects are negligible for hemispherical and optimum torispherical domes, and those are large for most of the general torispherical domes.