• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.4
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• pp.106-112
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• 2004

In particle or short-fiber reinforced composites, cracking or debonding of the reinforcements cause a significant damage mode because the damaged reinforcements lose load carrying capacity. The average stress in the inhomogeneity represents its load carrying capacity, and the difference between the average stresses of the intact and broken inhomogeneities indicates the loss of load carrying capacity due to cracking damage. The composite in damage process contains intact and broken reinforcements in a matrix. An incremental constitutive relation of discontinuously-reinforced composites including the progressive cracking damage of the reinforcements have been developed based on the Eshelby's equivalent inclusion method and Mori-Tanaka's mean field concept. Influence of the cracking damage on the stress-strain response of the composites is demonstrated.

• Korean Journal of Pharmacognosy
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• v.20 no.4
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• pp.243-253
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• 1989

Anatomical and physico-chemical properties of some nutrient and tonic crude drugs have been estimated and compared. Resin duct and druse crystal were observed more in Acanthopanax Cortex than in Ginseng Radix. Bast fiber bundle and solitary crystals were abandantly present in Glycyrrhizae Radix. Mucilage crude drugs contained mucilage ducts and bundles of raphides as common components and their arrangements of vascular bundles were different. TLC analysis showed different patterns of saponin, flavonoid, ${\gamma}-aminobutyric$ acid and sitosterols.

• Journal of KSNVE
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• v.7 no.3
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• pp.449-455
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• 1997

A theoretical study is presented for the prediction of the scattering of obliquely incident plane acoustic wave by transversely isotropic cylindrical shells immersed in water. In dorder to illustrate the vailidity of the theory backscattering form functions are compared with the existing results for degenerated problems: the catterings by isotropic shell and transversely isotropic solid cylinder. The unidirectional fiber reinforced boron-aluminum composites are selected as a model of transversely isotropic materials having potential applications in practice. From the resonant scattering analysis of the partial backscattering form functions, the dispersion curves for fluid-borne Stoneley wave, guided wave along the shell, and the lowest three Lamb type waves can be found. The Lamb type dispersions are compared with those of the flat plate. The variation of anisotropy significantly affects the properties of circumferential waves. From these results, it can be possible to identify parametrically the material properties of anisotropic cylindrical targets.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.6
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• pp.583-592
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• 2010

Equations of motion of thin-walled composite H-type cross-section beams exposed to concentrated harmonic and non-harmonic time-dependent external excitations, incorporating a number of nonclassical effects of transverse shear, primary and secondary warping, and anisotropy of constituent materials are derived. The forced vibration response characteristics of a composite H-type cross-section beam exhibiting the circumferentially asymmetric stiffness(CAS) configuration are exploited in connection with the structural bending-torsion coupling resulting from directional properties of fiber reinforced composite materials.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.11
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• pp.1604-1611
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• 2003

The experimental investigation of a coal splitter used in the 500㎿(e) boilers of fossil power plant is carried out to validate the design criteria. To predict air flow and the amount of particles at the exit, velocity and the weight of particles are measured on test planes using the coal splitter model with two-dimensional phase doppler particle analyzer and the glass fiber filter. It is found that the position of guide plate influences significantly both flow rates of gas and particle at the exit. Gas flow rate was a linear function of the guide plate, whereas particle flow rate was a exponential function of it.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.684-688
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• 1998

Optimization of the collocated piezoceramic sensor/actuator placement is investigated numerically and verified experimentally for vibration control of laminated composite plates. The finite element method is used for the analysis of dynamic characteristics of the laminated composite plates with the piezoceramic sensor/actuator. The structural damping index(SDI) is defined from the modal damping. It is chosen as the objective function for optimization. Weights for each vibrational mode are taken into account in the SDI calculation. The gradient method is used for the optimization. Optimum location of the piezoceramic sensor/actuator is determined by maximizing tie SDI. Numerical simulation and experimental results show that the optimum location of the piezoceramic sensor/actuator is dependent upon the outer layer fiber orientations of the plate, and location and size of the piezoceramic sensor/actuator.

• Textile Coloration and Finishing
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• v.21 no.5
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• pp.21-26
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• 2009

In order to analyze numerically the hydrophobicity of the new dyes synthesized for unmodified pure polypropylene fibers, the octanol-water partition coefficient (logP), which is one of molecular descriptors representing hydrophobicity of organic compounds, was obtained by a semi-empirical method using Chem3D software. For the dyes of higher logP than around 5, the affinity of the dyes towards unmodified polypropylene fiber was substantial. In contrast to the new dyes for polypropylene, conventional disperse dyes have logP values lower than 5 and exhibited poor affinity.

• Journal of Engineering Education Research
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• v.15 no.5
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• pp.140-150
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• 2012

The purpose of this study was to compare and analysis researches related the promising career and job outlook and to provide the direction for job choice to engineering students. Literature review and expert council were used to achieve the objectives of study. The result of this study was analyzed that these jobs were promising, that is, environmental scientist and specialist, earth scientist and hydrologist(education and research related career), architecture and architectural engineer, civil engineer, landscape technician, land surveyor map production expert photo surveyor surveying technician(construction related career), material engineer (mechanics and material related career), mine and geology engineer(chemistry, fiber and environment related career), computer system design and analyst, system software engineer, application software engineer, web specialist, and computer support specialist (electrical and telecommunication related career) and food engineer(food related career). In addition, health silver specialist, bio biomedical engineer, renewable energy specialist etc. were promising by considering social and economic trend for demographic change like aging and green growth.

• Science of Emotion and Sensibility
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• v.5 no.3
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• pp.67-74
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• 2002

Testing device was newly designed and built to measure the dynamic contact angle. The measurement was made using microscope interfaced with computerized image analysis system while the dynamic condition being controled using Instron. As specimens for the experiment, two different types of fibers, i.e., hydrophilic and hydrophobic, were prepared. In case of hydrophilic fiber, the increase of twist level gave the increase of contact angle. However, in hydrophobic yarn the increase of twist level gave the decrease of contact angle. When saline was used as a telling liquid, the increase of the concentration gave the increase of contact angle. The results rationalized clearly on the basis of known concepts could be used in designing fabric structure for the improvement of comport performance.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.1
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• pp.75-80
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• 2008

A scrapped fiber-reinforced plastic(FRP) fishing vessel causes many environmental problems, because technology development for recycling FRP vessel has not been adequately addressed. FRP is a main material for constructing a small coastal fishing vessel that is an object of reduction policy. Therefore, the FRP wastes derived a scrapped fishing vessel are increasing. In this study, I investigated an effective disposal process for FRP through the analysis of the actual conditions of scrapped FRP fishing vessel. The treatment processes of scrapped FRP fishing vessel are carried out with oil-removing, dismantling, intermediated processing(crushing), and then reclaiming follows burning in the final processing in Korea. However, in Japan, several recycling methods have been developed, for example, the incineration including thermal recovery, the use of cement-reclamation, and the use of asphalt concrete aggregate, because the method of reclaiming after incinerating which is generally used in Korea produces a toxic by-product such as dioxin.