• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.198-201
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• 2002

It has been well-blown that sandwich structures are efficient to resist bending loads by increasing the moment of inertia of the panel. However, the accurate theoretical prediction of failure load and its optimization of sandwich beams for strength under concentrated loads were so complicated. Moreover, the appropriate selection of the variables, such as face thickness, core density and core thickness of the sandwich beam with many theories has continuously researched to satisfy for the given strength to weight structural requirement. There will be interesting to investigate the effect of those variables with its optimization for the load resistance.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.397-402
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• 2003

Fracture resistance curves for concerned materials are required in order to perform elastic-plastic fracture mechanical analyses. Fracture resistance curve is built with J-integral values and crack extension values. The objective of this paper is to apply the load ratio method to the measurement of the crack length for the real scale pipe specimen. For these, the fracture test using the real scale pipe specimen and finite element analyses were performed. A 4-point bending jig was manufactured for the pipe test and the direct current potential drop method and the load ratio method was used to measure the crack extension and the length for the real scale pipe test. Finite element analyses about the compliance of the pipe specimen were executed for applying the load ratio method according to the crack length.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.709-713
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• 1996

The ceramic has such high qualities as light weight, abrasion resistance, heat resistance compared with metal, but since it is breakable, it can't be used as structural material and it is desirable to joining metal which is full of toughness, but, according as the ceramic/metal joint is executed at high temperature, the joint residual stress develops near the joint sides in the process of cooling the high temperature down to the suitable temperature due to difference of the thermal expansion coefficient between ceramic and metal, and the joint residualstress lowers the fracture strength. In this study, to ensure security and improvement of bending strength, 1 studies on see distribution shape of residual stress according to high thermal cycle, and the influnence of theraml cycle and distribution shape of residual stess on joint-strength.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.1
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• pp.16-21
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• 2004

In order to investigate the characteristics of diamond wheel grinding of ceramic materials, grinding resistance, surface roughness of ground surface and image of grinding wheel were acquired using experimental method. Through the experiments, this makes it possible to observe grinding wheel behavior by grinding resistance, surface roughness and cutting edge ratio. In case of $Al_2O_3$, cutting edge ratio is bigger than that of $ZrO_2$ and $Si_3N_4$. That's because $Al_2O_3$ has a characteristic of low fracture toughness and bending stress.

• Proceedings of the KWS Conference
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• 2005.11a
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• pp.171-173
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• 2005

Inconel 617 is a solid solution, nickel-chromium-cobalt-molybdenum alloy with an exceptional combination of high temperature strength and oxidation resistance. The combination of high strenth and oxidation resistance at temperatures over $1800^{\circ}F$ makes Inconel 617 an attractive material for such components as ducting, transition liners in both aircraft and gas turbine. In this study, the weldability and weldment characteristics of Inconel 617 are considered in GTAW associated with the two welding current and with back shielding gas using or not. After GTAW with 120A and 150A current, microstructures and hardness test, bending test, tensile test on room and elevated temperature for the determination of optical welding condition.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.319-323
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• 1999

This study is performed to evaluate the physical and mechanical properties and acid-resistance of oyster shell concrete. The result shows that the unit weights of concrete with oyster shell are decreased by 1∼2% than that of the normla cement concrete. The highest strength is achieved by 2.5% oyster shell filled oyster shell concrete, it is increased compressive strength by 4% , tensile strength by 6% and bending strength by7% than that of the normal cement concrete, respectively . The acid-resistanceis increased with increase of the content of oyster shell. It is 1.6 times of the normal cement concrete by 15% oyster shell filled oyster shell concrete. Accordingly, oyster shell concrete will improve the properties of concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.61-65
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• 2006

Urethane, epoxy, acrylic have common property to adhere on the concrete dried surface in the waterproofing materials at present. In the wet condition, however, the materials such as urethane, epoxy, acrylic need a long hardening time and it become a reason of water leakage as the materials breaking down. it is one of the problem to adhere to the substrate. Therefore, in this thesis, I focused to assure the structural safety and durability and quality for waterproofing and safe of construction cost by cut down the cost of labor and reduce the term of works as searching the application of field condition for hish adhesive spray type of degenerated and rubberized asphalt membrane material.

• The Korean Fashion and Textile Research Journal
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• v.12 no.4
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• pp.494-499
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• 2010

Knitted fabrics are very popular for their numerous advantages such as greater comfort, attractive garment appearance, better fit on the body, etc. In this study, we investigated the mechanical properties and abrasion property of warp knitted fabrics for footwear which treated with several softeners to improve abrasion resistance. The antistatic softener among the various softeners showed high improvement in abrasion resistance. Among the mechanical properties with treating conditions, WT (tensile energy), G (shear stiffness), B (bending rigidity) increased as treating timeincreased. But the other mechanical properties were little changed with treating concentration.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.308-313
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• 2002

In order to investigate the characteristics of grinding and diamond wheel grinding ceramic materials, grinding resistance, surface roughness of worked surface and image of grinding wheel were acquired using experimental method. Through the experiments, this makes it possible to observe grinding wheel behavior by grinding resistance, surface roughness and cutting edge ratio. In case of A1$_2$O$_3$, cutting edge ratio is begger than that of ZrO$_2$and Si$_3$N$_4$. That's because A1$_2$O$_3$has a characteristics of low fracture toughness and bending stress.

• Plant Resources
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• v.8 no.1
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• pp.32-35
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• 2005

This study was conducted to investigate the influence of $K_{2}O$ fertilizer application on growth, yield and lodging resistance of rice. Culm length and panicle length were lowest at the treatment of fertilizer level, $N-P_{2}O_{5}-K_{2}O=16-8-8$ plot but number of panicle, percentage of fruitful culm, $1{\ell}$ grain weights of paddy rice and brown rice, 1,000 grains weight of brown rice, brown rice ratio, yields of paddy rice and brown rice were highest at the treatment of fertilizer level, $N-P_{2}O_{5}-K_{2}O=16-8-8$ kg/10a plot. Bending moment, breaking strength and lodging index were lowest at the treatment of fertilizer level, $N-P_{2}O_{5}-K_{2}O=16-8-8$ kg/10a plot. Judging from the results reported above, an optimum fertilizer level of rice for lodging resistance is most likely be $N-P_{2}O_{5}-K_{2}O=16-8-8$ kg/10a treatment.