• Elastomers and Composites
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• v.5 no.2
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• pp.181-187
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• 1970

In vulcanizates of NR/SBR blending compounds, the physical properties decrease as the contents of SBR increase for the most part. but the abrasives showed reverse performance. However, since these conditions enough satisfy the requirements of tread, carcass and sidewall of tire, we found it was possible to take use of the quantity of SBR contained high on tire manufacturing.

• Tunnel and Underground Space
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• v.2 no.2
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• pp.190-198
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• 1992

This study is to summarize the contents for the investigation and design of the construction for oil storage. Since underground caverns are large scale, in their construction one should consider the mechanical stability of caverns and the economic view of construction. On the basis of them, cavern's section and layout were determined and water curtains were designed to maintain hydraulic equilibrium so that gases were sealed tightly. Also the supporting criterial for rock bolt and stotcrete were determined by means of the classification of rock masses and the results of finite element method. The criteria of grouting reinforcement were presented according to the results of injection test in the pilot holes of working face.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.567-572
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• 1999

Experimental study was conducted to investigate the flexural-shear behavior of hooked steel fiber reinforced high strength concrete (SFRHC) beams. Twenty beams with shear span-depth ratio of 1.45 were tested, of which variables were the contents of steel fiber with aspect ratio of 60, tension reinforcement ratio and concrete compressive of 60MPa and 80MPa. Test results has shown that shear failure of the beams were changed into flexural-shear failure or flexural failure according to increasing steel fiber content, that SFRHC with slump of 15cm over and fiber volume ratio of 1.5% was possible in practice, and that proper volume ratio of steel fiber was 1.5%.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.477-478
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• 2009

The objective of this study is to increase the insight of the mechanical behaviour of high-strength concrete prepared with fiber reinforcement after exposure to elevated temperatures. In particular, the result of the effects of contents of polypropylene fiber and level of preload on the residual compressive strength, load bearing and stress-strain curve of concrete are discussed

• Advanced Composite Materials
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• v.18 no.2
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• pp.167-185
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• 2009

Environmental problems caused by extensive use of polymeric materials arise mainly due to lack of landfill space and depletion of finite natural resources of fossil raw materials like petroleum or natural gas. The substitution of synthetic petroleum-based resins with natural biodegradable resins appears to be one appropriate measure to remedy the above-mentioned situation. This study presents the development of a composite that uses environmentally degradable starch-based resin as matrix and natural mineral basalt fibres as reinforcement, and investigates the fibre's and the composite's mechanical properties. The tensile strength of single basalt fibres was verified by means of single fibre tensile tests and statistically investigated by means of a Weibull analysis. Prepreg sheets were manufactured by means of a modified doctor blade system and hot power press. The sheets were used to manufacture specimens with fibre volume contents ranging from 33% to 61%. Specimens were tested for tensile strength, flexural strength and interlaminar shear strength. Composites manufactured during this study exhibited tensile and flexural strength of up to 517 MPa and 157 MPa, respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.718-723
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• 2000

Reinforced concrete is in general, known as high durability construction material under normal environments due to strong alkalinity of cement. It is, however, well known that moderate or minor cracks in reinforced concrete should be most serious causes to deteriorate the durability of RC structures. Futhermore, chloride contents penetrating through unexpected cracks in reinforced concrete bridges get to weaken corrosion resistance of reinforcement steel in concrete and then to accelerate the deterioration of concrete durability. The objective of this experimental research is 1) to evaluate the effect of various corrosion protection systems for reinforced concrete specimens with moderate or minor cracks which are exposed to cyclic wet and dry seawater, and then 2) to develop effective corrosion protection systems for reinforced concrete bridges under the exposure of various detrimental environments such as seawater, deicing and etc.

• Journal of Chest Surgery
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• v.22 no.6
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• pp.1088-1091
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• 1989

Foramen of Morgagni hernia is the least common type of all congenital diaphragmatic hernias. These foraminal hernias result from a congenital defect in the development or attachment of the diaphragm to the sternum and costal arch. They occur most commonly on the right side, possibly because of pericardial reinforcement of the left. In our case, occurred on the right side and the contents of the hernial sac were omental fat and a part of transverse colon. We performed transthoracic approach for reduction and repair of foraminal hernia with ligation and interrupted mattress sutures of the margin of the defected diaphragm to the posterior part of the sternum and costal cartilage. The postoperative course was uneventful except posttraumatic delirium and discharged at 21st postoperative day.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.837-840
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• 2002

An analysis method for rubber toughened PVC is suggested to evaluate critical dynamic strain energy release rates($G_c$) from the Charpy impact energy measurements. An instrumented Charpy impact tester was used to extract ancillary information concerning fracture parameters in addition to total fracture energies and maximum critical loads. The dynamic stress intensity factor $K_{Id}$ was computed for varying amounts of rubber contents from the obtained maximum critical loads and also toughening effects were investigated as well. The fracture surfaces produced under low velocity impact fur PVC/MBS composites were investigated by SEM. The results show that MBS rubber is very effective reinforcement material for toughening PVC.C.

• Journal of the Semiconductor & Display Technology
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• v.16 no.1
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• pp.52-58
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• 2017

Graphene oxide (GO)/carboxylated styrene-butadiene rubber (XSBR) nanocomposites with various contents of GO were prepared by a latex compounding method. It has been confirmed that the functional groups of GO and the hydrogen bonds between GO and XSBR are existed. It can be seen that the scorch time ($t_{s2}$), which is the measurement of incipient vulcanization of rubber, showed a delay after the addition of GO. Field emission scanning electron microscopy was employed to confirm the uniform dispersion of filler in the matrix. Indeed, with increasing fillers loading, the torque, tensile strength, thermal stability and crosslink density of obtained nanocomposites were improved. These results were correlated to the better dispersion of fillers through the rubber matrix.

• Proceedings of the Safety Management and Science Conference
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• 2004.05a
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• pp.219-231
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• 2004

The Charpy and Izod impact tests are the most prevalent techniques used to characterize the effects of high impulse loads on polymeric materials. An analysis method for rubber toughened PVC is suggested to evaluated critical dynamic strain energy release rates(G$_c$) from the Charpy impact tester was used to extract ancillary information concerning fracture parameters in additional to total fracture energies and maximum critical loads. The dynamic stress intensity factor KID was computed for varying amounts of rubber contents from the obtain maximum critical loads and also toughening effects were investigated as well. The fracture surfaces produced under low velocity impact for PVC/MBS composites were investigated by SEM. The results show that MBS rubber is very effective reinforcement material for toughening PVC.