• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.693-698
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• 2008

For designing intensity modulation type optical microphone, the irradiance distribution which can be applied to inclined-cut geometrical configuration is suggested. The model is important in analysis of response characteristics f3r intensity modulation type optical microphone. To overcome low sensitivity problem in intensity modulation type optical microphone, inclined-cut optical fiber is considered here. Based on optical geometry, the inclined-cut optical fiber sensor is designed and fabricated. The experiments are carried out to evaluate sensor performance.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.2
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• pp.145-152
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• 1983

An adhesively bonded anisotropic structure containing a part-through crack subjected to in-plane mixed mode deformations is investigated. The problem is reduced to a pair of Fredholm integral equations of the second kind by mathematical analysis. By solving these equations numerically stress intensity factors k$_{1}$ and k$_{2}$ are presented. Two cases are considered with respect to fiber orientations. Case one is to fix the fiber orientations of sound plate bonded to cracked plate with various fiber orientations. The other is to vary fiber orientations for both plates. As boundary conditions, tension and shear loading respectively, are applied to bonded anisotropic plates to observe mixed mode deformations.

• International Journal of Safety
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• v.2 no.1
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• pp.23-27
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• 2003

Recently, continuous fiber reinforced ceramic composite(CFCC) has attracted attention to a number of engineers because of its significant benefit for several industrial area. This work was conducted to provide a basic characteristic of CFCC for tensile loading condition. The numerical analysis by general purpose finite element program was accomplished and compared with an experimental tensile test. The stress strain curves were expressed well by the numerical analysis and the first matrix cracking stress was in accordance with that of the experimental result. Moreover, fracture pattern was shown by kill command graphically.

• Computers and Concrete
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• v.17 no.1
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• pp.67-86
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• 2016

Strengthening as well as correcting unsightly deflections of reinforced concrete (RC) beam may be accomplished by retrofitting. An innovative way to do this retrofitting that is proposed in this study utilizes turnbuckle to apply external post-tensioning. This Turnbuckle External Post-Tensioning (T-EPT) was experimentally proven to improve the serviceability and load carrying capacity of reinforced concrete beams. The T-EPT system comprises a braced steel frame and a turnbuckle mechanism to provide the prestressing force. To further develop the T-EPT, this research aims to develop a numerical scheme to analyze the structural performance of reinforced concrete beams with this kind of retrofitting. The fiber method analysis was used as the numerical scheme. The fiber method is a simplified finite element method that is used in this study to predict the elastic and inelastic behavior of a reinforced concrete beam. With this, parametric study was conducted so that the effective setup of doing the T-EPT retrofitting may be determined. Different T-EPT configurations were investigated and their effectiveness evaluated. Overall, the T-EPT was effective in improving the serviceability condition and load carrying capacity of reinforced concrete beam.

• Macromolecular Research
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• v.15 no.6
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• pp.587-594
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• 2007

Well defined amphiphilic diblock copolymers of poly(styrene-b-vinylbenzylphosphonic acid) (PS-b-PVBPA) were prepared by controlled radical polymerization technique, two-step hydrolysis reactions using trime-thylsilyl bromide from the corresponding phosphonic ethyl ester. By indirect, backward pH titration of the block copolymer, a good titration curve of a dibasic acid was observed. The IEC values obtained from both backward pH titration and volumetric back titration were almost identical. Thermal gravimetric analysis (TGA) of the phosphonic acid containing block copolymer showed a high thermal stability up to $400^{\circ}C$.

• Fibers and Polymers
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• v.2 no.4
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• pp.212-220
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• 2001

A series of polymeric dyes wre synthesized by free radical addition polymerication of monomeric dyes. The 2-amino-5-mrecapto-1,3,4-thiadiazole was diazotized and coupled with various N-arlmaleimides to give monomeric dyes. All the polymeric dyes were characterized by elemental analysis, infrared spectroscopy, visible absorption spectroscopy, viscometry. and thermogravimetric analysis. Color and dyeing properties of the polymeric dyes were discussed by comparing them with those of the corresponding monomeric dyes. The dyeing performance of these dyes was assessed on nylon fiber. These dyes were found to give various color shades with good to very good depth and levelness on the fiber. The dyeing of the monomeric dyes showed moderate fastness to light and good to excellent fastness properties. The dyebath exhaustion and fixation on nylon fiber has been found to be good.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.95-100
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• 1999

A FEA(finite element analysis model) was proposed to study stress and strain distributions in thick composites with fiber waviness and initial curvature under flexural loading. Three types of model with initial curvature were considered in this study: flat, concave and concave models. In the analysis, both material and geometrical nonlinearities were incorporated. Four point flexural tests were conducted on the flat specimens to obtain the flexural behavior of thick composites experimentally. It was concluded that the predictions from the models were in good agreement with the experimental results. It was shown that the stress and strain distributions as well as nonlinear flexural behaviors of thick composites were significantly affected by the fiber waviness and initial curvature.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.6
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• pp.541-550
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• 1997

Anaerobic chytridiomycete fungi are now well recognized as one of the major components of rumen microflora. Since the discovery of anaerobic fungi, the knowledge upon their morphology and physiology has been accumulated. It is certain that they gave roles in ruminal fiber digestion, although their quantitative contribution to rumen digestion is still unclear. Their role in fiber digestion is complicated by the dietary factors and the interaction with other microorganisms. We aim at reviewing such information in this article. Considerable attention gas been paid to the polysaccharidase of these fungi. Analysis on the fungal genes encoding these enzymes has been performed in several laboratories. This article also covers the genetical analysis of fungal polysaccharidases.

• Journal of the Optical Society of Korea
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• v.9 no.2
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• pp.54-58
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• 2005

A novel mode analysis method and differential mode delay measurement technique for a multimode optical fiber based on optical frequency domain reflectometry has been proposed for the first time. We have used a conventional OFDR with a tunable external cavity laser and a Michelson interferometer. A few-mode optical multimode fiber was prepared to test our proposed measurement technique. The differential mode delay (DMD) of the sample fiber was measured to be 16.58 ps/m with a resolution of 1.5 ps/m. We have also compared the OFDR measurement results with those obtained using a traditional time-domain measurement method.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.10a
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• pp.171-177
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• 1995

Fracture mechanics does work for concrete, provided that one uses a proper, nonlinear form of fracture mechanics in which a finite nonlinear zone at fracture front is being considered. The fracture process zone is a region ahead of a traction-free crack, and the development of model of fracture process zone is most important to describe fracture phenomena in concrete. This paper is about fracture behavior of concrete cylinder under lateral pressure. Concrete cylinders were made of high strength normal connote, steel fiber reinforced concrete and steel fiber reinforced polymer-impregnated concrete and concrete and the fracture behavior such as cracking propagation and ultimate load are observed. The fracture process zone is modelled by a Dugdale-Barenblatt type model with linear tension-softening curve and are implemented to the boundary element technique for the fracture analyses of the cylinders. The experimental results are compared with analysis results and tension-softening curves for the steel fiber reinforced concrete and steel fiber reinforced polymer-impregnated concrete are obtained by back analyses.