• Journal of the Korean Society for Precision Engineering
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• v.23 no.2 s.179
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• pp.51-56
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• 2006

This paper shows the development of flexible force sensor using the fiber Bragg grating. This force sensor consists of a Bragg grating fiber and flexible silicone rubber (DC184, Dow corning co. Ltd). This sensor does not have special structure to maximize the deflection or elongation, but have good sensitivity and very flexible characteristics. In addition, this sensor has the immunity to the electro magnetic field and can be multiplexed easily, which is inherited from the characteristics of fiber Bragg grating sensor. In the future, this sensor can be utilized the tactile sensor system minimizing the sensor size and developing the fabrication method.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.180-185
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• 2004

This paper shows how can be controlled the rubber tired TRAM by electromagnetic field with a specific pattern as autonomous driving system. The system is composed with drive elements. steering elements. navigational devices. transmitter/receivers and sensor means for sensing the position relative to the magnetic markers. There are difficulties in sensing track conditions. curvatures. slops etc. forward compared to that of the control system optically. The sensing track conditions previously is important for running stability and riding comfort. This paper shows how can achieve track condition in advance by means of electromagnetic pattern originally.

• Macromolecular Research
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• v.10 no.6
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• pp.345-358
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• 2002

The electrical conductivity during vulcanization process was measured as a function of time for the system of TiC loaded styrene-butadiene rubber (SBR) composites. The phenomenon of negative and positive temperature coefficients of conductivity and its conduction mechanism were also studied for the SBR polymeric composites. The current-voltage characteristics of the polymeric composites were non-linear in high voltage and showed a switching effect. The effects of temperature on the thermal conductivity and effective dielectric constant were measured. The measured parameters were found to be dependent on TiC concentration. The electromagnetic wave shielding (EMS) of the SBR-TiC polymeric composite was also examined. The SBR filled with TiC could be expected to be promising novel smart polymeric composites for self-electrical heating, temperature sensor, time delay switching, and electro-magnetic wave shielding effectiveness.

• Polymer(Korea)
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• v.29 no.2
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• pp.156-160
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• 2005

$\alpha,\omega-Vinyl$ poly (dimethyl-methylphenyl) siloxane prepolymer (VPMPS ) was prepared by the equilibrium polymerization of octamethylcyclotetrasiloxane $(D_4)$, 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane $(D_3^{Me,Ph)$, and 1,1,3,3-tetramethyl-1,3-divinyldisiloxane (MVS). And also, of $\alpha,\omega-hydrogen$ poly(dimethyl-methyl)siloxane prepolymer (HPDMS) as end blocker was prepared from octamethylcyclotetrasiloxane $(D_4)$, 1,3,5-trimethylcyclotrisiloxane $(D_3^:Me,H})$, and 1,1,3,3-tetramethyldisiloxane (MS). Nickel ferrite nanoparticles having spinel magnetic material was prepared by the sol-gel method using PAA as a chelating agent. Poly(organosiloxane) rubber nanocomposite containing silica and nickel ferrite ultrafine powder modified with 1,3-divinyltetramethyldisilazane (VMS) was prepared by compounding VPMPS, HPDMS, and catalyst in high speed dissolver. The mechanical properties, heat dissipating away characteristics, and volume resistivities for POX-30 and POX-50 were measured.

• Polymer(Korea)
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• v.34 no.1
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• pp.69-73
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• 2010

Effects of reaction time and temperature on the isomerization and dehydrobromination reactions of brominated butyl rubber were investigated. The structural composition of brominated butyl rubber was determined by Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy($^1H$-NMR), Density functional theory (DFT) was used to study on the isomerization and dehydrobromination mechanisms of model compounds. The geometries for model compounds of 3-bromo-5,5,7,7-tetramethyl-2(2',2',4',4'-tetramethyl)pentyl-1-octylene (3BrOE), 1-bromo-5,5,7,7-tetramethyl-2(2',2',4',4'-tetramethyl)pentyl-2-octylene (1Br2OE) and 5,5,7,7-tetramethyl-2(2',2', 4',4'-tetramethyl)pentyl-1,3-octadiene (CD) had been optimized by using density functional theory at B3LYP/3-21G and B3LYP/6-31G levels. The predicted energy of 3BrOE lies higher than that of 1Br2OE which suggests that 1Br2OE configuration is more stable than the 3BrOE configuration. Compared with the energy barrier, the pathway of dehydrobromination is less competitive than that of isomerization. This is qualitatively consistent with the experimental results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.885-886
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• 2011

• Progress in Superconductivity and Cryogenics
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• v.19 no.2
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• pp.14-18
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• 2017

This study presents three dimensional (3-D) seeding technique which is a modification of interior seeding. 3-D seeding is beneficial for shortening the processing period and enhancing the magnetic properties of REBCO bulk superconductors fabricated by melt growth. Oxygen channels were provided by using divided powder compacts instead of by using a rubber insert. Microstructure observations revealed that the grains grown from the seeds impinged each other and formed low angle grain boundaries of (001)/(001). It has been shown that the 3-D seeding technique reduces the volume fraction of a-c growth sector and thereby maximizes the area of a-b growth sector which attribute to the high magnetic characteristics of single grain REBCO bulk superconductors.

• Journal of the Korean Ceramic Society
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• v.29 no.3
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• pp.177-182
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• 1992

The effect of heat-treatment temperature on the microwave absorbing properties was investigated in Ni0.8Zn0.2Fe2O4 specimens. The composite specimens were prepared by modling and curing the mixture of prereacted ferrite powder and silicone rubber. The measurement of complex permeability and permittivity was made by the reflection/transmission method. The most sensitive material constants with heat-treatment temperature is the imaginary (loss) component of permeability. The higher the heat-treatment temperature, the greater the magnetic loss. The composite specimens with high magnetic loss exhibited superior microwave absorbing properties. The quantitative estimation of microwave absorbing properties were made by plotting the observed material constants on the calculated solution map of impedance-matching.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.496-503
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• 2001

The suspension of the optical pickup actuator is damped by the presence of silicone rubber damper bond at its termination. In spite of the presence of it, the actuator still exhibits a strong mechanical resonance which affects its settling time and vibrational characteristics. This resonance can cause errors in reading information from the disk, particularly in high speed CD-ROM and DVD-ROM drives. Ferrofluids are stable colloidal suspensions of sub-micron sized magnetic particles in a carrier liquid. In the actuator design, ferrofluid is applied to the surface of the magnets until the quantity is sufficient to maintain intimate contact with the bobbin/carrier assembly. The fluid is retained in the magnetic field and its viscosity provides the desired mechanical damping to the moving assembly, improving the actuators settling time and vibrational characteristics. Access time is also improved, particularly on warped or eccentric discs.

• Journal of the Korean Magnetics Society
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• v.14 no.5
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• pp.174-179
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• 2004

Attenuation of conduction noise through microstrip line attached with the high lossy iron flakes-rubber composites has been investigated in GHz frequencies. Microstrip line was designed with characteristic impedance of 50 $\Omega$ and a length corresponding to the center frequency of 3 GHz. Iron flakes were fabricated by mechanical forging of spherical iron powders using an attrition mill. The fabricated microstrip line shows a ideal propagation characteristics of S$\sub$11/ < -60 dB and S$\sub$21/ = 0 dB. Attaching a noise absorbing sheet on the microstrip line, S$\sub$11/ increases to about -10 dB and S$\sub$21/ decreases to -20～-60 dB depending on the length of absorbing sheet. The calculated power loss is as high as 80% in the frequency range 2～8 GHz. It is suggested that the most critical material parameter is magnetic loss for the enhancement of noise attenuation.