• 한국실내디자인학회논문집
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• 제25호
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• pp.262-271
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• 2000

Nowadays tiles are widely used as architectual material because of their external beauty, solidity with fire-resisting and water-resisting qualities, and convenience for construction, preservation and repairs. Owing to the improvement of living standard and makers scramble for tile markets, we regard tiles as art and culture. Tiles have been developed with technical improvement, based on mutual relation of material and design. The purpose of the third firing is to create high value added as we show artistic merit and decorative effect. For this reason, researches on new material and design have been carried out widely. I made researches whole process from design to printing by means of computer and experiment with color and vetroza of the third firing. I hope that tile makers will share the achievement of university researchers and this paper will be useful for those who are interested in tiles.

• 산업공학
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• 제18권4호
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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.

• 한국전기전자재료학회논문지
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• 제17권1호
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• pp.31-38
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• 2004

PMN-PT, a piezoelectric single crystal, has many useful applications such as sensors and actuators. In this paper, all the elastic, piezoelectric, and dielectric constants of the PMN-32％PT single crystals were measured by the resonance method. For the rhombohedral symmetry, a total of twelve independent material constants were measured such as six elastic compliance constants at constant electric field, two dielectric constants at constant stress, and four piezoelectric constants d. Seven sets of crystal samples of each different geometry were prepared for the measurement of length-thickness extensional, thickness extensional, radial, length extensional and thickness shear modes of vibration, respectively. In order to check the validity of the measurement, experimental impedance spectrum of the PMN-PT crystal was compared with numerical data spectrum calculated with the measured material constants. The good agreement between the two spectra confirmed validity of the results in this paper.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.476-479
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• 1997

A Knowledge of friction force in pneumatic cylinders makes it possible to improve cylinder description during simulation and to asses performance under changing operating conditions more accurately. Such knowledge is particularly useful, for example, when modeling continuous pneumatic positioning systems or predicting the operating conditions under which stick slip may occur, as well as in establishing preventive maintenance procedures for pneumatic cylinders. Friction force depends on a number of factors, including operating pressure, seal running speed on the cylinder barrel and rod, barrel material and surface roughness, seal dimensions and profile, seal material, lubrication conditions, cylinder distortion during assembly, and the operating temperature of cylinder components. This paper shows a system for measuring the friction force caused by a seal used in pneumatic cylinders. Results of experimental tests show that seal friction forces for grease lubricated service are clearly dependent on speed and pressure and are les sensitivity to other parameter. i.e., barrel material and roughness, seal material, and profile.

• Structural Engineering and Mechanics
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• 제16권2호
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• pp.115-126
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• 2003

A novel finite element model based on the incremental endochronic theory with the effect of temperature was developed in this study to explore the deformed behaviors of a flexible pavement material. Three mesh systems and two loading steps were used in the calculation process for a specimen of three-dimensional circular cylinder. Computational results in the case of an uni-axial compression test for temperatures at $20^{\circ}C$ and at $40^{\circ}C$ were compared with available experimental measurements to verify the ability of developing numerical scheme. The isotropic response and the deviatoric response due to the thermal effect were presented from deformations in different profiles and displacement plots for the entire specimen. The characteristics of changing asphalt concrete material under a specified loading condition might be seen clearly from the numerical results, and might provide an useful information in the field of road engineering.

• 한국정밀공학회지
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• 제25권11호
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• pp.95-99
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• 2008

Applications of composite materials in various engineering fields have been extended significantly. For being useful composite materials, we could modify the rigidity and strength characteristics of composite material according to structures and material direction. In this study, CFRP, which has been widely used in space leisure and general structural applications due to the weight, elasticity coefficient, high fatigue strength and lower thermal transformation ect, was selected. As the CFRP is an anisotropic material whose mechanical properties change with its stacking sequence or angle, special attention was given to the effects of the fiber orientation angle on the bending characteristics of CFRP fiat and CFEP square members. It's different on the each result of strength and rigidity of CFRP flat and CFRP square members.

• 동력기계공학회지
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• 제11권1호
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• pp.127-133
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• 2007

SG-365 steel is an important material and used for manufacturing a pressure vessel which the gas piping. In this investigation, the elastic plastic fracture toughness of this material is evaluated by the unloading compliance method according to the ASTM E813-97 and E1152-97 method on the smooth and side groove 1CT specimens. The effect of smooth and side groove is studied on the elastic plastic fracture toughness. The side grooved specimen is very useful in estimation of the $J_{IC}$. It is much easier than the smooth specimen to the onset of the ductile tearing by the R curve method. Besides, it improves the accuracy of toughness values, decreases a phenomenon of the tunneling and shear lip by the side groove.

• Journal of Mechanical Science and Technology
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• 제15권10호
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• pp.1417-1422
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• 2001

Since fracture surface presents clear evidence to describe the circumstances of material failure event, analysis of fracture surface should provide plenty of useful information for failure prevention. Thus if we extract proper information from the fracture surface, the safety evaluation, for plant component could be more accurate. In general, the chaotic morphology of fracture surface is determined by the degree of material degradation as well as by other factors such as type of load, geometry of specimen, notch condition, microstructure of material and environment. In this research, we developed a fractal analysis technology for the fracture surface of aged turbine rotor steel based on the slit-island technique using an image analyzer. Moreover the correlation between the fractal dimension and the aging time was studied.

• Korean Membrane Journal
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• 제1권1호
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• pp.50-58
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• 1999

Symmetric asymmetric and composite perfluoropolymer membranes made with HYFLON AD have been prepared and evaluated. Porous and non porous symmetric membranes have been prepared by solvent evaporation with various processing conditions. Non-contact atomic force microscopy (AFM) was used to investigate the membrane morphology in air. Analysis of the images gave quantitative imformation on the surface pore strcture in particular on the pore size distributin. Possible useful uses of porous membranes are envisaged in the field of gas-liquid separations such as membrane contactors (MSc) Molecular Dynamics(MD) simulations structure of HYFLON AD 60X copolymer supporting these results are also reported. Amorphous perfluoropolymer membranes appears to be ideal other than in MCs when separation processes have to be performed in hostile environments i.e. high temperatures and aggressive non-aqueous media such as chemicals and solvents. In these cases HYFLON AD mem-branes can exploit the outstanding resistance of perfluoropolymers.

• Structural Engineering and Mechanics
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• 제40권1호
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• pp.49-64
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• 2011

An analytical method is presented to investigate electromagnetothermoelastic behaviors of a hollow sphere composed of functionally graded piezoelectric material (FGPM), placed in a uniform magnetic field, subjected to electric, thermal and mechanical loads. For the case that material properties obey an identical power law in the radial direction of the FGPM hollow sphere, exact solutions for electric displacement, stresses, electric potential and perturbation of magnetic field vector in the FGPM hollow sphere are determined by using the infinitesimal theory of electromagnetothermoelasticity. Some useful discussion and numerical examples are presented to show the significant influence of material inhomogeneity. The aim of this research is to understand the effect of composition on electromagnetothermoelastic stresses and to design optimum FGPM hollow spheres.