• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.5
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• pp.193-198
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• 2015

In the study, electroless Ni-plating on flexible ethylene-propylene-diene-monomer (EPDM) rubber sheets for the application of an insert block for shielding electromagnetic interference of multi cable transit (MCT) systems was investigated. Ni crystallinity and adhesion have been found to vary with processing parameters such as pH and temperature of the plating bath. It was shown that Ni-films having the high crystallinity and optimum electric conductivity were obtained on EPDM rubber sheets under pH 7 and 8 at $60{\sim}70^{\circ}C$. The conductive Ni-plated EPDM rubber prepared at pH 7 at $70^{\circ}C$ showed the enhanced adhesion and electric conductivity, and the high electromagnetic interference shielding effect in the 400 MHz~1 GHz range.

• Journal of the Korean Geotechnical Society
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• v.24 no.6
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• pp.69-75
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• 2008

Shear tests were carried out on interface between two concrete eco-blocks which comprise segmental retaining wall. Three interface conditions were considered : 1) direct contact of two blocks, 2) placing rubber pad between two blocks, 3) placing rubber pad and shear key between two blocks. According to shear tests, shear load-shear displacement relationship which was obtained from direct contact of two blocks was similar to elastic-perfectly plastic behavior. Ductile behavior of shear load-shear displacement relationship was observed for the interface condition of placing rubber pad. Apparent minimum shear capacities and apparent friction angles for the interface conditions of direct contact of two blocks, placing rubber pad between two blocks, placing rubber pad and shear key were 1.7 kN/m, $27.6^{\circ}$ and 4.2 kN/m, $26.2^{\circ}$ and 20.9 kN/m, $26.0^{\circ}$ respectively.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.6
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• pp.622-628
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• 2013

Due to the development of compounding technology, there is a considerable increase in the number of high performance rubbers in the world. Accordingly, there are rapid growing requests about high performance tires such as UHP tire and Run-flat tire. However, it is extremely difficult to investigate the friction coefficient of tire tread rubbers. An alternative solution must be developed with the reliability of high-speed linear friction test machines. The use of friction test machines can be expected to improve rubber friction researches. In this paper, we propose a new kind of high-speed linear friction test machine. We have designed and manufactured various mechanisms for friction tests. The final goals are to design and manufacture friction test machines that can investigate friction coefficients efficiently and rapidly. The performance of the proposed high-speed linear friction test machine is evaluated experimentally; however additional study should be necessary for safer and more reliable experimentation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.305-306
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• 2006

In process for production of Rubber Scheme Product that have the most inferior Working Environment is Medicine mixture and Scheme processing. Applying automation and Environment Treatment technology to the hazardous chemical and mixture processing, Through developed 'Mixture Automatic Machine for hazardous chemical Interruption type that is occurred at mixing rubber medicines', we try to decline worker's intensity of labour, Also overcomes solution of work evasion phenomenon and manpower supply and demand's difficulty by forming agreeable working environment and through the automatic scheme and mixture processing by preventing that hazardous chemical had known as disease causes of various importance disease is exposed to worker during the work. and we plan to do so that production of high added value product may be available.

• Elastomers and Composites
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• v.51 no.4
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• pp.301-307
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• 2016

Additive manufacturing (AM), so called 3D Printing is a new manufacturing process and is getting attraction from many industries. There are several methods of 3D printing. Among them fused deposition modeling (FDM) type is most widely used by reason of cheap maintenance, easy operation and variety of polymeric materials. Articles manufactured by 3D printing have weak deposition strength compared with conventionally manufactured products. Deposition strength of FDM type 3D printed article is highly dependent of deposition temperature. Subsequently the nozzle temperature in the FDM type 3D printing is very important and it is controlled by heat source in the 3D printer. Nozzle is connected with heat block and barrel, and heat block contains heat source. Nozzle becomes hot through heat conduction from heat source. Nozzle temperature has been predicted for various thermal boundary conditions by computer simulation and compared with experimental measurement. Nozzle temperature highly depends upon thermal conductivities of heat block and nozzle. Simulation results are good agreement with experiment.

• Elastomers and Composites
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• v.27 no.3
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• pp.161-173
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• 1992

A series of polyurethane block copolymers based on hydroxyterminated poly(dimethyl siloxane), poly(propylene glycol) and poly(tetramethylene glycol) soft segments of molecular weights 1,809, 2,000 and 2,000, respectively, were synthesized. The hard segments consisted of 4,4'-diphenylmethane diisocyanate and 1,4-butanediol as the chain extender. Samples with different molar ratios were prepared. We tried to synthesize poly(dimethyl siloxane)-based polyurethane(PDMS-PU) containing a hard block as major fraction and a soft block as minor fraction for preparing toughened rigid systems. After a study of the pure PDMS-PU, poly(propylene glycol)-based polyurethane(PPG-PU) and poly(tetramethylene glycol)-based polyurethane(PTMG-PU), (mixed polyol)-based block copolymers and blends between PDMS-PU, PPG-PU and PTMG-PU were prepared, and characterized by means of differential scanning calorimetry, tensile testing and scanning electron microscopy. In (mixed polyol)-based PU and in lower hard segment content blends, macro-phase separation was shown, but blends with higher hard segment contents showed significant reduction in amounts of phase separation.

• Journal of the Korean Society of Safety
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• v.30 no.1
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• pp.66-71
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• 2015

Safety, resilience and comfort of pedestrian were assessed by the British Pendulum Test and SB/GB factor test at 8 kinds of sidewalk pavement. Sidewalk paving materials were normal concrete, porous concrete, concrete block, soil concrete, asphalt, rubber chip/resin mixture, wood chip/resin mixture and floor tile. In addition, a survey was conducted to investigate the perception of pedestrians on the sidewalk paving material. As a result, while the skid resistance value was measured in the most 60BPN above, the floor tile showed a low value of about 30BPN. The ratios of SB factor to GB factor of the elastic pavements(rubber/resin mixture and wood chip/resin mixture) appeared to be relatively large when compared with those of the conventional sidewalks. The survey showed that respondents perceived as more safe and comfortable elastic pavements compared to conventional pavements. Approximately 50% of respondents answered that hardened soil pavement was the most environmentally friendly.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.331-338
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• 2001

Seismic performances of the base isolated model of Five Story Stone Pagoda were studied through shaking table tests. Friction pendulum system (FPS), Pure-friction system with laminated rubber bearing (LRB) and Ball with rubber bearing were selected fur the comparison of performances. Performances of specially designed isolation systems were tested dynamically using shaking table. The test results of isolated model are compared with those of fixed base model. Compared with fixed base model, the isolated model showed that it could withstand much higer intensity of earthquake motion. The Effective Peak Ground Acceleration (EPGA) value of isolated model when the top component tipped over was above twice of that value in case of fixed base model. According to the additional test results, the lower value of coefficient of friction than that of common frictional base isolation systems is more effective to protect the piled multi-block system of Pagoda against moderate intesity of ground motion.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.953-957
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• 2005

Light Rail Transit(LRT) Systems with transport capacity between subway and bus(5,000-25,000 persons per hour) are being carried on over 100 lines around the world. In Korea, to solve the urban transportation problem, the introduction of LRT system has been proceeded positively. It is planned to develop the Korean standard LRT system in which safety, efficiency and cost effectiveness are emphasized. So we were able to make proto type of Rubber tired AGT system for LRT. This is capable of driverless operation using CBTC(Communication Based Train Control) of Moving Block System and is currently making an experiment for reliability in test-line. This study is focused on verifving the train tracking with CBTC in driverless and ATO mode through implementing the examination.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.264-269
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• 2005

Light Rail Transit(LRT) Systems with transport capacity between subway and bus(5,000-25,000 persons per hour) are being carried on over 100 lines around the world, In Korea, to solve the urban transportation problem, the introduction of LRT system has been proceeded positively. It is planned to develop the Korean standard LRT system in which safety, efficiency and cost effectiveness are emphasized. So we were able to make proto type of Rubber tired AGT system for LRT. This is capable of driverless operation using CBTC(Communication Based Train Control) of Moving Block System and is currently making an experiment for reliability in test-line. This study is focused on verifving the performance of CBTC system for driverless and ATO mode through implementing the examination.