• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1163-1166
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• 2004

Cinnamate group is well-known for the dimerization reaction by ultra-violet irradiation and cinnamate polymers are studied for photo-alignment materials. The cinnamate groups of flexible polymer are found to produce LC alignment parallel to polarization direction of ultra-violet light, which is contrary to the LC orientation on conventional cinnamate polymers. The un-reacted cinnamate groups in the flexible polymer are also found to participate in cycloadducts formation by additional thermal reaction that preserves the orientation of cycloadducts, leading to the enhancement of thermal stability of LC alignment.

• Applied Science and Convergence Technology
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• v.24 no.1
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• pp.1-8
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• 2015

Protein immobilization on a gold surface plays an important role in the usefulness of biosensors that utilize gold-coated surfaces such as surface plasmon resonance (SPR), quartz crystal microbalance (QCM), etc. For developing high performance biosensors, it is necessarily required that immobilized proteins must remain biologically active. Loss of protein activity and maintenance of its stability on transducer surfaces is directly associated with the choice of immobilization methods, affecting protein-protein interactions. During the past decade, a variety of strategies have been extensively developed for the effective immobilization of proteins in terms of the orientation, density, and stability of immobilized proteins on analytical devices operating on different principles. In this review, recent advances and novel strategies in protein immobilization technologies developed for biosensors are briefly discussed, thereby providing an useful information for the selection of appropriate immobilization approach.

• The Korean Journal of Ceramics
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• v.3 no.4
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• pp.257-262
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• 1997

Aluminum nitride(AIN) thin films were deposited on SiO$_2$/Si substrates by reactive sputtering for the application of SAW devices. The major deposition parameters such as pressure, nitrogen fraction, rf power, substrate distance were changed to find out the optimal condition for c-axis oriented thin films on an amorphous substrate. The effects of deposition parameters on the crystal structure, residual stress, and growth morphology of thin films were characterized by XRD, SEM, and TEM. The FWHM of (002) rocking curve of the films deposited at the proper condition was lower than 2.2$^{\circ}$(C=0.93$^{\circ}$). Cross-sectional TEM showed that self-aligned structure was developed just after slightly random growth at the initial stage. The frequency characteristics of test device fabricated from AIN thin films confirmed their piezoelectric property and applicability for SAW devices.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.890-893
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• 2006

Effects of the evaporation rate of MgO films using electron beam were investigated on the MgO properties and the discharge characteristics of the plasma display panel (PDP). The evaporation rate was changed from 3 ${\AA}/sec$ to 15 ${\AA}/sec$ at a substrate temperature of $300\;^{\circ}C$. MgO properties such as crystal orientation, surface roughness, contact angle, and film structure were inspected using XPS, AFM, drop shape analysis and SEM. We also studied the relation between MgO properties and PDP discharging characteristics. The minimum firing voltage and maximum efficacy were obtained at evaporation rate of 5 ${\AA}/sec$. In the MgO film deposited at 5 ${\AA}/sec$, (200) orientation was most intensive and surface roughness was minimum.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.420-422
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• 1995

PVDF (polyvinylidene fluoride) has at least from known crystalline structure ( ; they are referred to as the $\alpha$, $\beta$, $\gamma$ and $\alpha_p$ phase or forms II, I, III and $IV_p$). In this study, the manufactured PVDF thin films through vapor deposition method had for II ( ; the substrate temperature at 30$^{\circ}C$). The dielectric behavior of poly(vinylidene fluoride) is affected by orientation and crystal modification. The very high value of the dielectric constant for high temperature conditioned film is believed to be due to the orientation effect. The loss peak caused by molecular motion of the molecules in crystalline regions.

• Korean Journal of Materials Research
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• v.9 no.5
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• pp.473-477
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• 1999

Xerographic properties of double-layer photoconductor doped with 4-butyl-4'-methoxyazobenzene (BMAB) as charge-carrier transport material were investigated. BMAB can undergo reversible trans-cis isomerization by light with appropriate wavelength. In the results of measured surface voltage properties for photoconductor doped with BMAB, TNF: BMAB(4-wt%) sample with trans form showed the lowest dark decay, the lowest residual voltage, and the highest sensitivity among cis form. The trans isomer of BMAB has ordering orientation because the molecule possesses a rodlike shape, while the cis isomer has random orientation due to its bent shape. Therefore the molecular arrangement of trans form enhanced charge-carrier transport mobility.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.550-552
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• 2003

We prepared $Co_{77}Cr_{20}Ta_3$ Magnetic layer for perpendicular magnetic recording media with introduce Two-step methode and Amorphous Si Underlayer on slide glass substrate. The thickness of magnetic layer were 100nm, and Underlayer were varied from 5 to 100 nm. The multi layer Properties of crystal structure were examined with XRD. Prepared thin films showed improvement of dispersion angle of c-axis orientation ${\Delta}{\theta}_{50}$ caused by inserting Buffer-layer and amorphous Si underlayer.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1479-1481
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• 2002

AlN thin films were deposited on Si(100) and $SiO_2$/Si substrates using R.F. magnetron sputtering system. The effect of various deposition conditions on the crystal orientation of AlN films was investigated to obtain a highly (002)-oriented films. SAW filters were fabricated using AlN films with various thicknesses and their frequency response characterizations were measured. Experimental results showed that the (002)-orientation and surface roughness of AlN films played a crucial role of determining the frequency response of AlN SAW devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.5
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• pp.536-540
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• 2004

A novel nematic liquid crystal (LC) cell with splay structure exhibiting wide viewing angle, fast response time and high transmittance at the same time has been developed. With rubbed homeotropic alignment in parallel directions, the device shows bend alignment in the absence of vertical electric field. However, with applied high voltage in a pulse form, the LC shows a optically compensated splay (OCS) orientation such that the mid-director is parallel to a substrate and at both surfaces the LCs are aligned vertically in parallel direction. In the device, the birefringence of the cell becomes tunable with applying voltage, i.e., the amount of light passed through the cell can be controlled by controlling the orientation of the LC. Since the OCS cell has a self-compensation structure such that the LC has a mirror symmetry along the mid-director, the device shows a wide viewing angle with only a single domain and a fast response time.

• Journal of the Korean institute of surface engineering
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• v.46 no.2
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• pp.55-60
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• 2013

Superhard TiN coatings were fabricated by DC and ICP (inductively coupled plasma) assisted magnetron sputtering techniques. The effect of ICP power, ranging from 0 to 300 W, on coating microstructure, preferred orientation mechanical properties were systematically investigated with HR-XRD, SEM, AFM and nanoindentation. The results show that ICP power has a significant influence on coating microstructure and mechanical properties of TiN coatings. With the increasing of ICP power, coating microstructure evolves from the columnar structure of DC process to a highly dense one. Grain sizes of TiN coatings were decreased from 12.6 nm to 8.7 nm with increase of ICP power. The maximum nanohardness of 67.6 GPa was obtained for the coatings deposited at ICP power of 300 W. Preferred orientation in TiN coatings also vary with ICP power, exerting an effective influence on film nanohardness.